281 results on '"Donglin Liu"'
Search Results
102. Key algorithms study on global terrain visualization.
- Author
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Liqiang Zhang 0001, Chongjun Yang, Peng Dong, and Donglin Liu
- Published
- 2003
- Full Text
- View/download PDF
103. Planning and Evaluation of Electric Vehicle Charging Stations Considering the Service Range
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Rongjiang Yu, Zhenyu Gao, Zhonghua Chen, Donglin Liu, Caiqian Wang, Qian Hu, Yu Wu, and Yufei Wang
- Published
- 2021
104. A Web-based Technique to Generate and Visualize 3D Scenes from Global to Local Views.
- Author
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Liqiang Zhang 0001, Chongjun Yang, Donglin Liu, and Hongwen Lin
- Published
- 2003
- Full Text
- View/download PDF
105. Sequence retrieval from genomic databases.
- Author
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Gautam B. Singh and Donglin Liu
- Published
- 2001
- Full Text
- View/download PDF
106. Sales, Sales Management and Front-line Employee Issues: NOVEL SALE PREDICT MODEL USING SUPPORT VECTOR MACHINE: EVIDENCE FROM CHINA'S C2C PLATFORM.
- Author
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Jinzhe Yan, Jaekang Heo, Yening Zhou, Donglin Liu, and Soomin Lim
- Subjects
CONSUMERS' reviews ,SUPPORT vector machines ,CLASSIFICATION algorithms ,SALES management - Abstract
The article focuses on the development of a Support Vector Machine (SVM) model to predict sales using data from China's C2C platform. The study addresses the importance of consumer reviews in influencing purchasing decisions on C2C platforms, especially for products like mobile phones sold by companies like Xiaomi and Huawei.
- Published
- 2023
107. Comprehensive analysis of the long non‑coding RNA expression profile and functional roles in a contrast‑induced acute kidney injury rat model
- Author
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Zhigang Xiao, Weiwei Bao, Ping Tan, Mingfang Huang, Donglin Liu, and Zhiqing Wang
- Subjects
0301 basic medicine ,Cancer Research ,long non-coding RNA ,Oncogene ,Competing endogenous RNA ,RNA ,RNA sequencing ,Articles ,General Medicine ,Biology ,Fold change ,Long non-coding RNA ,Cell biology ,Pathogenesis ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,contrast-induced acute kidney injury ,Immunology and Microbiology (miscellaneous) ,030220 oncology & carcinogenesis ,microRNA ,co-expression analysis ,competing endogenous RNA ,Gene - Abstract
Long non-coding RNAs (lncRNAs) have been identified as a class of regulatory RNAs that participate in both physiological and pathological conditions, including acute kidney injury. However, the roles of lncRNA dysregulation in the pathogenesis of contrast-induced acute kidney injury (CI-AKI) are largely unknown. In the present study, the expression profiles of lncRNAs in kidney tissue were compared between rats with CI-AKI and controls using high-throughput RNA sequencing. In total, 910 differentially expressed (DE) lncRNAs (DElncRNAs), including 415 downregulated and 495 upregulated lncRNAs, were identified at 12 h after intra-arterial iodinated contrast medium injection (fold change ≥2; P
- Published
- 2021
108. Multiband User Equipment Prototype Hardware Design for 5G Communications in Sub-6-GHz Band
- Author
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Xin Quan, Xiangjie Xia, Kai Kang, Donglin Liu, Ying Liu, Chenxing Li, Wensheng Pan, Youxi Tang, and Qiang Xu
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Hardware architecture ,Radiation ,business.industry ,Computer science ,MIMO ,020206 networking & telecommunications ,02 engineering and technology ,Condensed Matter Physics ,Base station ,User equipment ,PHY ,0202 electrical engineering, electronic engineering, information engineering ,Baseband ,Electrical and Electronic Engineering ,Wideband ,business ,Field-programmable gate array ,Computer hardware - Abstract
Verification of physical (PHY) layer and medium access control (MAC) layer procedures of the fifth-generation (5G) specifications with real hardware prototypes is important in the commercialization of 5G mobile communication systems and is challenging as well. In this paper, we propose a flexible software-defined-radio (SDR)-based prototype hardware design for user equipment (UE), which can be used to implement novel 5G communication concepts. The proposed hardware architecture is featured by using a flexible baseband signal processing module and two independent programmable wideband radio frequency (RF) front ends that, respectively, cover the lower and higher frequencies of sub-6-GHz band. The flexibility of the baseband signal processing module is ensured by using four powerful field-programmable gate arrays (FPGAs) running the PHY entities and a powerful FPGA-based system-on-chip running the MAC entities. The flexibilities of the RF front ends lay in the facts that: 1) the design covers three sub-6-GHz frequency bands, that is, 2.5, 3.5, and 4.9 GHz; 2) it can support dual connectivity for the upcoming 5G networks; and 3) it enables carrier aggregation (CA) over up to three carriers to achieve 300-MHz bandwidth. Accordingly, this prototype is capable of verifying the complicated scheduling procedures, evaluating the sophisticated signal processing algorithms in both PHY and MAC layers, and supporting the 100-MHz 4T4R multiple-input multiple-output (MIMO) or 200-MHz 2T2R MIMO techniques. Experiments have been performed on 256-QAM modulated waveforms to assess transmission power, error vector magnitude, adjacent channel leakage ratio from the UE side, and peak data rates between a base station and the UE.
- Published
- 2019
109. Power Control and Inter-node Interference Cancellation in Full-Duplex Networks with Residual Self-Interference
- Author
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Donglin Liu and Fei Wu
- Subjects
Computer science ,Node (networking) ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,Duplex (telecommunications) ,020206 networking & telecommunications ,02 engineering and technology ,Transmitter power output ,Topology ,Interference (wave propagation) ,Computer Science Applications ,Base station ,Single antenna interference cancellation ,Telecommunications link ,Computer Science::Networking and Internet Architecture ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Electrical and Electronic Engineering ,Computer Science::Information Theory ,Power control - Abstract
We consider a three-node full-duplex (FD) network, where an FD capable base station serves double mobile nodes operating in half-duplex mode. The self-interference at the base station and the inter-node interference (INI) between the uplink and the downlink nodes in the network are both taken into account. We consider the power control and the base station assisted INI suppression for sum achievable rate maximization subject to the transmit power constraints at the base station and the nodes. By reformulating this non-convex problem and separating it into two independent sub-problems, we propose a search method to solve it. We evaluate the performance of the proposed method in a single-cell scenario. The proposed method significantly outperforms other recently developed methods.
- Published
- 2019
110. Post-traumatic stress disorder and its risk factors in bereaved Tibetan adolescents 3 years after the 2010 Yushu earthquake, a cross-sectional study in China
- Author
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Xiaolian Jiang, Yingqi Xiao, Kun Liu, and Donglin Liu
- Subjects
Male ,China ,Adolescent ,Cross-sectional study ,Poison control ,Tibet ,Suicide prevention ,Occupational safety and health ,Stress Disorders, Post-Traumatic ,03 medical and health sciences ,0302 clinical medicine ,Risk Factors ,Surveys and Questionnaires ,Adaptation, Psychological ,Injury prevention ,Earthquakes ,Humans ,Survivors ,Child ,030504 nursing ,Traumatic stress ,Human factors and ergonomics ,Checklist ,030227 psychiatry ,Cross-Sectional Studies ,Female ,Self Report ,Pshychiatric Mental Health ,0305 other medical science ,Psychology ,Bereavement ,Clinical psychology - Abstract
Objectives This study examined the incidence of symptomatological post-traumatic stress disorder (PTSD) in bereaved Tibetan adolescents 3 years after the 2010 Yushu earthquake, then to identify possible and relational risk factors of PTSD by a cross-sectional study. Methods A total of 867 bereaved Tibetan adolescents seriously impacted by the 2010 earthquake were investigated. Symptomatological PTSD was evaluated by the PTSD Checklist–Civilian Version. And coping styles were evaluated by the Coping Styles Scale. Exposure of trauma to the 2010 Yushu earthquake was evaluated by a checklist about earthquake containing sociodemographic variables. Results 3 years after the Yushu earthquake, 24.4% of the bereaved Tibetan adolescents had symptomatological PTSD. The results also indicated that coping styles and disaster-related experiences after the 2010 earthquake were connected with PTSD among survivors. When the 2010 earthquake struck, those having symptomatological PTSD were more probably to be buried/injured/amputated, and to witness burial/injury/death, and to have property damage. An individual who adopted positive coping skill was probably to have less symptomatological PTSD. Conclusions The results showed that the existence of PTSD in bereaved Tibetan adolescents in the Yushu earthquake was very prevailing after 3 years. Effective psychological rescue work should be carried out, especially targeting bereaved Tibetan adolescents with more severe PTSD.
- Published
- 2019
111. Multiple Access Channels With Full-Duplex Amplify-and-Forward Transmitter Cooperations
- Author
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Donglin Liu, Qingpeng Liang, and Chuan Huang
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General Computer Science ,Iterative method ,Computer science ,02 engineering and technology ,Data_CODINGANDINFORMATIONTHEORY ,Amplify-and-forward (AF) ,Residual ,symbols.namesake ,full duplex (FD) ,0202 electrical engineering, electronic engineering, information engineering ,parametric Dinkelbach algorithm ,sequential convex programming (SCP) ,General Materials Science ,Parametric statistics ,Computer Science::Information Theory ,Covariance matrix ,Transmitter ,General Engineering ,020206 networking & telecommunications ,multiple access channel (MAC) ,semidefinite relaxation (SDR) ,Additive white Gaussian noise ,Transmission (telecommunications) ,Single antenna interference cancellation ,symbols ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,Algorithm ,lcsh:TK1-9971 ,Decoding methods ,Communication channel - Abstract
In this paper, a full-duplex (FD) transmitter cooperative scheme is proposed to improve the achievable rate for multiple access channels (MACs). In the proposed scheme, by leveraging the FD amplify-and-forward (AF) protocol, two FD transmitters send their own signals and forward the received signals from their counterparts to the receiver, which adopts both the forward and backward decoding schemes to decode the source messages. First, the analyses of the equivalent channel model and the statistics of the accumulated additive white Gaussian noise and residual self-interference (ANRI) caused by imperfect self-interference cancellation are performed. Then, the achievable rate regions are obtained by utilizing both the forward and backward decoding schemes, and a two-stage iterative algorithm is proposed to characterize these regions: in each iteration, the covariance matrix of the ANRI is first updated; then, for the fixed covariance matrix of the ANRI, the transmission parameters of the two transmitters are calculated by a two-step iterative algorithm based on the parametric Dinkelbach algorithm, sequential convex programming (SCP), and semidefinite relaxation (SDR). The numerical results show that the proposed scheme outperforms the half-duplex cooperative scheme and conventional MAC scheme without cooperations when the channels between the two transmitters are in good condition.
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- 2019
112. Chromosome-scale Cerasus humilis genome assembly reveals gene family evolution and possible genomic basis of calcium accumulation in fruits
- Author
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Yang Zhao, Guangjun Fu, Jinyu Jiang, Yingchao Li, Xiaojuan Liu, Jian Li, Jingyu Sun, Qi Wang, Donglin Liu, Zhumei Luo, Shuxia Ding, Quanxin Bi, Changchun Shi, and Libing Wang
- Subjects
Horticulture - Published
- 2022
113. Alternate Interchange Signing Study for Indiana Highways
- Author
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Stanley Chen, Yaobin Chen, Renran Tian, Lingxi Li, Donglin Liu, Jue Zhou, and Dan Shen
- Subjects
Indiana interstate highway ,highway interchange signing - Abstract
The main objectives of this research were to (1) understand signing issues from the perspective of drivers and (2) develop recommendations for improving interchange signing in Indiana to aid driver understanding and increase the safety and efficiency of highway traffic operations. An online survey with specific questions was designed and distributed through email, social media, online newspapers, and a survey company with the goal of better understanding driver thinking when approaching decision-making areas on the interstate. The analysis of the survey results revealed the following. •Drivers usually do not know the interchange types as they approach an interchange on the freeway. •Drivers are most interested in which lanes they should be in when approaching an interchange, even in advance of typical signing locations. •Drivers do not like signs that require cognitive work since it will delay their driving decision by creating uncertainty. •Different drivers need different types of information from signs, such as cardinal direction, destination name, road name, and lane assignments. Therefore, a perfect sign for one driver may be confusing or information overload for another driver. •In some instances, a driver who is familiar with the area is confused by the signs because the sign information contradicts the driver’s knowledge.
- Published
- 2021
114. PACdb: PolyA Cleavage Site and 3'-UTR Database.
- Author
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J. Michael Brockman, Priyam Singh, Donglin Liu, Sean Quinlan, Jesse Salisbury, and Joel H. Graber
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- 2005
- Full Text
- View/download PDF
115. Three-Dimensional Numerical Simulation of Inductively Coupled Plasma Generator
- Author
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Bao Weimin, Xiaoping Li, Yue Niu, Yanming Liu, and Donglin Liu
- Subjects
Electromagnetic field ,Coupling (physics) ,Materials science ,Field (physics) ,Physics::Plasma Physics ,Turbulence ,Physics::Space Physics ,Mechanics ,Plasma ,Inductively coupled plasma ,Wind tunnel ,Magnetic field - Abstract
Taking the inductively coupled plasma wind tunnel that studies the blackout of reentry vehicle in the aerospace field as the research object, the discharge state of the plasma generator under large size, high power and high pressure is studied. Through the multi-field coupling of turbulent field, electromagnetic field and temperature field, a three-dimensional numerical simulation of the rotating inlet flow and heat transfer process of an inductively coupled plasma generator with a power of 1MW is carried out, and the distribution law of the magnetic field intensity, the temperature and velocity in the tube are obtained. At the same time, the physical mechanism of the formation of each distribution and the influence of rotating intake on the plasma discharge characteristics are analyzed. These provide basic theoretical data for the optimization design of the inductively coupled plasma wind tunnel and its industrial application.
- Published
- 2020
116. Population Pharmacokinetics of Caspofungin among Extracorporeal Membrane Oxygenation Patients during the Postoperative Period of Lung Transplantation
- Author
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Zhu Zhang, Donglin Liu, Qingyuan Zhan, Chen Wang, Wenqian Chen, Qianlin Wang, Pengmei Li, Min Li, Gang Cui, and Xianglin Zhang
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Male ,Critical Illness ,medicine.medical_treatment ,Population ,03 medical and health sciences ,chemistry.chemical_compound ,Extracorporeal Membrane Oxygenation ,0302 clinical medicine ,Pharmacokinetics ,Caspofungin ,lung transplantation ,polycyclic compounds ,medicine ,Extracorporeal membrane oxygenation ,Humans ,Lung transplantation ,Pharmacology (medical) ,Postoperative Period ,Renal replacement therapy ,skin and connective tissue diseases ,education ,Retrospective Studies ,Pharmacology ,Volume of distribution ,0303 health sciences ,education.field_of_study ,Lung ,030306 microbiology ,business.industry ,030208 emergency & critical care medicine ,biochemical phenomena, metabolism, and nutrition ,bacterial infections and mycoses ,surgical procedures, operative ,Infectious Diseases ,medicine.anatomical_structure ,chemistry ,Anesthesia ,business ,pharmacokinetics - Abstract
Little is known about the influence of extracorporeal membrane oxygenation (ECMO) on the pharmacokinetics (PK) of caspofungin. The aim of this study was to describe population PK of caspofungin in patients with and without ECMO during the postoperative period of lung transplantation (LTx) and to investigate covariates influencing caspofungin PK. We compared ECMO patients with non-ECMO patients, and patients before and after ECMO weaning as self-controls, to analyzed changes in caspofungin PK. Eight serial blood samples were collected from each patient for PK analysis., Little is known about the influence of extracorporeal membrane oxygenation (ECMO) on the pharmacokinetics (PK) of caspofungin. The aim of this study was to describe population PK of caspofungin in patients with and without ECMO during the postoperative period of lung transplantation (LTx) and to investigate covariates influencing caspofungin PK. We compared ECMO patients with non-ECMO patients, and patients before and after ECMO weaning as self-controls, to analyzed changes in caspofungin PK. Eight serial blood samples were collected from each patient for PK analysis. The population PK of caspofungin was described using nonlinear mixed-effects modeling. Twelve ECMO and 7 non-ECMO lung transplant recipients were enrolled in this study. None of the patients received renal replacement therapy during any part of the study period. The PK of caspofungin was best described by a two-compartment model. There were no significant differences in the PK parameters and concentrations of caspofungin among the ECMO, non-ECMO, and self-control group. In the final covariate model, we found that there was a significant association between the male gender and increased distribution volume, that a higher sequential organ failure assessment score was related to an increase in intercompartmental clearance, and that a longer operative time was related to an increase in clearance and the volume of distribution. ECMO did not have a significant impact on the PK of caspofungin in patients after LTx. Some factors were identified as statistically significant covariates related to the PK of caspofungin; however, their impact on clinical practice of caspofungin needs to be investigated further in more studies. (This study has been registered at ClinicalTrials.gov under identifier NCT03766282.)
- Published
- 2020
117. Simulation on Electrostrictive-force induced Cavitation Formation Process in Cyclohexane
- Author
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Qiang Liu, Donglin Liu, and Zhangdong Wang
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010302 applied physics ,Materials science ,Electrostriction ,Cyclohexane ,Multiphysics ,Electron ,Mechanics ,01 natural sciences ,010305 fluids & plasmas ,Physics::Fluid Dynamics ,chemistry.chemical_compound ,Acceleration ,chemistry ,Cavitation ,0103 physical sciences ,Compressibility ,Physics::Chemical Physics ,Voltage - Abstract
Streamer, known as the pre-breakdown process, has been widely studied in insulating liquids such as mineral oil. Due to the complexity of the composition of mineral oil, cyclohexane, a simple hydrocarbon-based liquid is often used in some fundamental studies. The mechanism during streamer initiation stage may differ under different voltage rising rates. Cavitation is likely to form under fast-rising voltage, which helps to trigger streamer initiation due to the acceleration of electrons inside the cavities. This paper simulates the electrostrictive force induced cavitation formation process in cyclohexane and its influencing factors. Cyclohexane is considered as compressible liquid. The threshold of cavitation formation in cyclohexane is estimated to be −6 MPa. Coupled Poisson equation and Navier-stoke equations are solved by finite element method in COMSOL Multiphysics for cavitation formation simulation. A needle-plane geometry is used and different voltage rising rates are modelled. Simulation results show that it is possible for electrostrictive force to lead to cavitation formation in the vicinity of needle tip in cyclohexane under fast rising voltage. The liquid is pushed towards the needle tip due to the electrostrictive force. Voltage application with slower rising rate leads to more liquids to move but requires higher voltage magnitude to form cavitation. The absolute value of the minimum magnitude of negative pressure in cyclohexane increases with the increase of voltage rising rate.
- Published
- 2020
118. Local Structural Investigation of (Ba,Ca)(Zr,Ti)O 3 and Ca(Zr,Ti)O 3 by X‐Ray Fluorescence Holography
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Yuta Yamamoto, Koji Kimura, Ahmed Gadelmawla, Keisuke Kawamura, Hina Sugimoto, Donglin Liu, Qiang Li, Qingfeng Yan, Neamul H. Khansur, Naohisa Happo, Ken‐ichi Kakimoto, Kyle G. Webber, and Kouichi Hayashi
- Subjects
Condensed Matter Physics ,Electronic, Optical and Magnetic Materials - Published
- 2022
119. Measurement on electron density of high-power and large-volume ICP-heated wind tunnel with HCN laser interferometer
- Author
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Weifeng Deng, Yanming Liu, Jia Zhang, Xiaoping Li, Donglin Liu, and Weimin Bao
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Physics::Plasma Physics ,Physics::Space Physics ,Condensed Matter Physics - Abstract
This paper explains the physical behavior of the electron density of high-power and large-volume plasma wind tunnel using a single channel hydrogen cyanide (HCN) laser interferometer. Based on the characteristics of inductively coupled plasma (ICP)-heated wind tunnel, the temperature and pressure distribution of the ICP-heated wind tunnel are obtained from numerical simulations, during which the influence of neutral particles is considered to calculate the accurate electron density. The typical electron density order of ICP-heated wind tunnel is [Formula: see text]. We discovered that there is a positive correlation between the electron density of argon plasma jet and mass flow rate, while that of air plasma jet decreases slightly. We also found that the peak of electron density appears when the argon is switched to air. Within the voltage range of 6–10 kV, the electron density of argon and air plasma increases slowly. However, when the voltage increases from 10 to 12 kV, the electron density of air plasma increases sharply with the mass flow rate of 15 g/s. Finally, the electron density of argon plasma is much higher than that of air plasma at the same mass flow rate and voltage.
- Published
- 2022
120. Ultrasmall Fe@Fe
- Author
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Donglin, Liu, Jiaojiao, Li, Chengbin, Wang, Lu, An, Jiaomin, Lin, Qiwei, Tian, and Shiping, Yang
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Diagnostic Imaging ,Caffeic Acids ,Solubility ,Neoplasms ,Acrylic Resins ,Human Umbilical Vein Endothelial Cells ,Contrast Media ,Humans ,Particle Size ,HCT116 Cells ,Magnetite Nanoparticles ,Magnetic Resonance Imaging ,Polyethylene Glycols - Abstract
Targeted T
- Published
- 2020
121. Modelling the Electrostrictive-force induced Cavitation Formation Process in Dielectric Liquids
- Author
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Boyan Liu, Donglin Liu, Zhongdong Wang, and Qiang Liu
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010302 applied physics ,Materials science ,Cyclohexane ,Electrostriction ,Multiphysics ,0211 other engineering and technologies ,Relative permittivity ,02 engineering and technology ,Dielectric ,01 natural sciences ,Threshold voltage ,Surface tension ,chemistry.chemical_compound ,chemistry ,Cavitation ,0103 physical sciences ,021108 energy ,Composite material - Abstract
Pre-breakdown phenomenon in dielectricliquids, also called streamer, has been widely investigated tounderstand the breakdown mechanism of dielectric liquids.The possibility of streamer initiation due to electrostrictiveforce induced cavitation formation under fast-rising voltagewaveform is studied in this paper. The finite element method(FEM) based modelling is conducted by coupling Poissonequation and Navier-stoke equations in COMSOLMultiphysics. The pressure threshold of cavitation formationin cyclohexane and rapeseed oil is estimated to be -6 MPa and -9.31 MPa, respectively, which are 3-5 times smaller than thatin deionized water (-30 MPa). This is mainly due to smallersurface tension coefficients of oils than deionized water. Adetailed description on the dynamics of cavitation formation indeionized water is first presented and then compared withthose in cyclohexane and rapeseed oil. Results showed that theelectrostrictive pressure increases with the increasing appliedvoltage, which pushes local liquid towards the needle tip at tensof m/s and leads to large negative pressure in the vicinity ofneedle tip. Cavitation appears in the area where local negativepressure reaches the threshold. The electrostrictive pressure indeionized water is around 100 and 60 times larger than that incyclohexane and rapeseed oil, respectively, under the sameconditions due to the larger relative permittivity of deionizedwater. Therefore, it is much harder to initiate cavitation incyclohexane and rapeseed oil than in deionized water. Inaddition, the voltage magnitude thresholds for cavitationformation are comparable between cyclohexane and rapeseedoil under different voltage rising rates.
- Published
- 2020
122. Magnetic-Photoacoustic Dual-Mode Probe for the Visualization of H
- Author
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Chenglin, Yan, Donglin, Liu, Lu, An, Yurui, Wang, Qiwei, Tian, Jiaomin, Lin, and Shiping, Yang
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Cell Survival ,Surface Properties ,Magnetic Phenomena ,Mice, Nude ,Neoplasms, Experimental ,HCT116 Cells ,Ferric Compounds ,Magnetic Resonance Imaging ,Cell Line ,Photoacoustic Techniques ,Mice ,Animals ,Humans ,Nanoparticles ,Hydrogen Sulfide ,Particle Size ,Colorectal Neoplasms ,Copper - Abstract
Techniques for the qualitative and quantitative detection of H
- Published
- 2020
123. Ultrathin circular polarimeter based on chiral plasmonic metasurface and monolayer MoSe
- Author
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Qiao, Jiang, Bowen, Du, Meiling, Jiang, Donglin, Liu, Zhixin, Liu, Bowen, Li, Zheng, Liu, Feng, Lin, Xing, Zhu, and Zheyu, Fang
- Abstract
Two-dimensional materials are ideal platforms for intriguing physics and optoelectronic applications because of their ultrathin thicknesses and excellent properties in optics and electronics. Further studies on enhancing the interaction between light and two-dimensional materials by combining metallic nanostructures have generated broad interests in recent years, such as enhanced photoluminescence, strong coupling and functional optoelectronics. In this work, an ultrathin circular polarimeter consisting of chiral plasmonic metasurface and monolayer semiconductor is proposed to detect light with different circular polarization within a compact device. A designed chiral plasmonic metasurface with sub-wavelength thickness is integrated with monolayer MoSe
- Published
- 2020
124. Synergetic Sensing Effect of Sodium Carboxymethyl Cellulose and Bismuth on Cadmium Detection by Differential Pulse Anodic Stripping Voltammetry
- Author
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Faxiang Wang, Jiaqian Wei, Wang Jianhui, Xin Luo, Donger Chen, Donglin Liu, Liu Dongmin, Shouen Huang, Ning Jingheng, and Yongle Liu
- Subjects
inorganic chemicals ,Materials science ,Stripping (chemistry) ,Metal ions in aqueous solution ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Article ,Analytical Chemistry ,Bismuth ,bismuth ,medicine ,Electrical and Electronic Engineering ,sodium carboxymethyl cellulose ,cadmium detection ,Instrumentation ,Detection limit ,Cadmium ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Carboxymethyl cellulose ,Electrochemical gas sensor ,differential pulse anodic stripping voltammetry ,Anodic stripping voltammetry ,chemistry ,0210 nano-technology ,Nuclear chemistry ,medicine.drug - Abstract
In the present work, a novel electrochemical sensor was developed for the detection of trace cadmium with high sensitivity and selectivity in an easy and eco-friendly way. Firstly, a glassy carbon electrode (GCE) was modified with nontoxic sodium carboxymethyl cellulose (CMC) by a simple drop-casting method, which was applied to detect cadmium by differential pulse anodic stripping voltammetry (DPASV) in a solution containing both target cadmium and eco-friendly bismuth ions, based on a quick electro-codeposition of these two metal ions on the surface of the modified electrode (CMC-GCE). Investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FT-IR), both CMC (with good film-forming ability) and bismuth (with well-defined stripping signal) were found to be well complexed with target cadmium, leading to vital signal amplification for cadmium detection at a sub-nanomolar level. Under the optimal conditions, the proposed sensor exhibited a good linear stripping signal response to cadmium (Ⅱ) ion, in a concentration range of 0.001 &mu, mol/L&ndash, 1 &mu, mol/L with a limit of detection of 0.75 nmol/L (S/N = 3). Meanwhile, the results demonstrate that this novel electrochemical sensor has excellent sensitivity and reproducibility, which can be used as a promising detection technique for testing natural samples such as tap water.
- Published
- 2019
- Full Text
- View/download PDF
125. Hamilton-connectivity of Interconnection Networks Modeled by a Product of Graphs
- Author
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Donglin Liu, Shaohui Wang, and Chunxiang Wang
- Subjects
Discrete mathematics ,Panconnectivity ,Interconnection ,General Computer Science ,Applied Mathematics ,Modeling and Simulation ,010102 general mathematics ,010103 numerical & computational mathematics ,0101 mathematics ,01 natural sciences ,Engineering (miscellaneous) ,Graph - Abstract
The product graph Gm *Gp of two given graphs Gm and Gp , defined by J.C. Bermond et al.[J Combin Theory, Series B 36(1984) 32-48] in the context of the so-called (Δ,D)-problem, is one interesting model in the design of large reliable networks. This work deals with sufficient conditions that guarantee these product graphs to be hamiltonian-connected. Moreover, we state product graphs for which provide panconnectivity of interconnection networks modeled by a product of graphs with faulty elements.
- Published
- 2018
126. Electric Field Simulation of Needle Tips with Different Shape Formations Using FEM Method
- Author
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Donglin Liu, Zhongdong Wang, and Qiang Liu
- Subjects
Laplace's equation ,Materials science ,Mason equation ,Electric field ,Electrode ,Geometry ,Dielectric ,Radius ,Finite element method ,Apex (geometry) - Abstract
Needle-plane (NP) electrode is the most widely-used geometry to study the characteristics of streamer in dielectric liquids. The arc angle, apex angle and the hyperbolic shape are identified as the key variables to describe a needle shape in the literature. Four different needle tip shape formations were adopted in this paper to study their effects on the needle tip electric field (NTEF). The calculation of NTEF was based on Laplace equation solved by finite element method (FEM). Mason equation was also used to calculate NTEF as a comparison. It was found that for a fixed NP electrode configuration with a needle tip radius (NTR) of 3 µm, the apex angle has an obvious effect. NTEF at a small apex angle of 10° is 4.6 times larger than NTEF at a large apex angle of 90°. Larger NTR leads to smaller variation of NTEF for different apex angles. Besides, NTEF of a hyperbolic needle tip is equal to that of a needle tip with a specific apex angle. This apex angle increases from around 30° to around 74° when NTR rises from 3 µm to 100 µm. Mason equation gives a good estimation of NTEF at small NTR in NP configuration when hyperbolic needle tip shape is taken. The difference of NTEF calculated by FEM and Mason equation for hyperbolic shape needles becomes larger with the increase of NTR.
- Published
- 2019
127. Clinical characteristics and diagnosis of a rare case of systemic AL amyloidosis: a descriptive study
- Author
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Pengguo Chen, Jin Qi, Jianfang Hu, Hui Liu, Donglin Liu, Zhaohan Wang, and Zhibin Gong
- Subjects
amyloidosis ,Pathology ,medicine.medical_specialty ,business.industry ,Pleural effusion ,Amyloidosis ,H&E stain ,030204 cardiovascular system & hematology ,medicine.disease ,Staining ,03 medical and health sciences ,hepatomegaly ,0302 clinical medicine ,Oncology ,Pathognomonic ,030220 oncology & carcinogenesis ,Eosinophilic ,AL amyloidosis ,Medicine ,business ,Research Paper ,Rare disease - Abstract
Systemic amyloidosis is a rare disease involving multiple organs. It is difficult to establish diagnosis as the symptoms is diverse and non-specific. And without specific therapy the prognosis is very poor. We analyzed detailed clinical and laboratorial data of a 53-year-old male patient. The characteristic features included refractory pleural effusion, extraordinary hepatomegaly and cardiac failure. The illness lasted 9 months and therapy period spanned 4 months. Fine needle biopsy of liver, lung, heart, pancreas and kidney was performed. Immunohistochemistry, immunofluorescence, Congo staining and hematoxylin and eosin staining were performed. All specimens were stained pink with haematoxylin and eosin staining. Amorphous deposits of eosinophilic material were visible within the Congo red dye stained liver tissue whereas under cross-polarized light pathognomonic apple-green birefringence of amyloid deposits was visible. At last systemic AL amyloidosis diagnosis was confirmed. The report showed an unusual AL amyloidosis case in detail which would be helpful for physician in clinical work.
- Published
- 2018
128. Semi-Blind SI Cancellation for In-Band Full-Duplex Wireless Communications
- Author
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Youxi Tang, Bo Zhao, Xumin Pu, Shihai Shao, Fei Wu, and Donglin Liu
- Subjects
Computer science ,business.industry ,Duplex (telecommunications) ,020302 automobile design & engineering ,020206 networking & telecommunications ,02 engineering and technology ,Interference (wave propagation) ,Computer Science Applications ,Power (physics) ,Reduction (complexity) ,0203 mechanical engineering ,Interference (communication) ,Channel state information ,Modeling and Simulation ,Frequency domain ,Phase noise ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Overhead (computing) ,Wireless ,Electrical and Electronic Engineering ,business ,Computer Science::Information Theory ,Coherence (physics) - Abstract
Blind known self-interference cancellation (BKSC) is particularly attractive in self-interference (SI) reduction for full-duplex (FD) systems, because it requires no interference channel state information (CSI) and the overhead of capturing the full CSI on SI can be saved. In this letter, a semi-blind SI cancellation method is proposed for FD systems under phase noise. By applying the idea of BKSC in the frequency domain, this method is designed to extract partial CSI of the SI for removing the interference that results from differential operations in BKSC schemes. The closed-form expression for the power of the residual SI is also derived in the presence of phase noise. As a low-complexity method that requires no specific pilot design or complex estimation algorithms, the proposed scheme can effectively suppress the SI signal in the presence of phase noise, which outperforms conventional least-square-based SI cancellation schemes.
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- 2018
129. Piezoelectric Property of a Tetragonal (Ba,Ca)(Zr,Ti)O3 Single Crystal and Its Fine-Domain Structure
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Jaeshik Shim, Qiang Li, Yue Sun, Qingfeng Yan, Wenhui He, Huajing Fang, and Donglin Liu
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010302 applied physics ,Phase boundary ,Flux method ,Piezoelectric coefficient ,Materials science ,Condensed matter physics ,Crystal growth ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Polarization (waves) ,01 natural sciences ,Piezoelectricity ,Condensed Matter::Materials Science ,Tetragonal crystal system ,0103 physical sciences ,General Materials Science ,0210 nano-technology ,Single crystal - Abstract
A tetragonal (Ba,Ca)(Zr,Ti)O3 (BCZT) single crystal was grown by a flux method, and the piezoelectric coefficient (d33) was characterized. The piezoelectric response was proved to be associated with polarization extension, which was successfully used to explain the variation in d33*. From the intrinsic aspect, the compositional effect on Landau free-energy profiles was discussed, showing an “extender” nature of the as-grown crystal and the increasing tendency of structural instability toward the morphotropic phase boundary. From the extrinsic aspect, the evolution of domain structure under various external fields (electric and temperature) was studied, revealing that the fine-domain structure of the as-grown BCZT single crystal was stable to E-field and temperature. The results manifest possibilities of further improving the piezoelectric property of the BCZT single crystal, which requires optimization of the crystal growth technique in future work.
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- 2018
130. Mitigation of the inter-node interference in multi-antenna full-duplex networks
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Wanzhi Ma, Fei Wu, and Donglin Liu
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Beamforming ,Engineering ,business.industry ,Node (networking) ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,05 social sciences ,Multi antenna ,050801 communication & media studies ,020206 networking & telecommunications ,Data_CODINGANDINFORMATIONTHEORY ,02 engineering and technology ,Interference (wave propagation) ,Expression (mathematics) ,Base station ,Matrix (mathematics) ,0508 media and communications ,Telecommunications link ,Computer Science::Networking and Internet Architecture ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Electrical and Electronic Engineering ,business ,Computer Science::Information Theory - Abstract
When multiple single-antenna half-duplex (HD) nodes communicate with a full-duplex (FD) base station equipped with multiple transmit and receive antennas, the uplink nodes would generate inter-node interference (INI) on the downlink nodes. We propose a base station assisted INI suppression scheme. The scheme is to design a proper amplify-and-forward matrix at the base station so that the sum achievable rate of the uplink and downlink is maximized. We derive the close-form expression of the amplify-and-forward matrix, which is the product of a parameter optimization and a zero-forcing beamforming (ZFBF) matrices. Finally, we investigate the performance of the proposed INI suppression scheme in a single cell.
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- 2018
131. Anisotropic temperature–electric field phase diagrams and domain structure evolution in rhombohedral Mn-doped PIN–PMN–PT single crystals
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Fangping Zhuo, Chao Xu, Qiang Li, Yiling Zhang, Qingfeng Yan, Yaming Zhou, Donglin Liu, and Xiangcheng Chu
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010302 applied physics ,Phase transition ,Polarized light microscopy ,Materials science ,Condensed matter physics ,02 engineering and technology ,General Chemistry ,Dielectric ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Polarization (waves) ,01 natural sciences ,Piezoelectricity ,Electric field ,0103 physical sciences ,General Materials Science ,0210 nano-technology ,Anisotropy ,Phase diagram - Abstract
Domain pattern evolution driven by temperature and electric (E) field in [100]-, [110]- and [111]-poled Mn-doped Pb(In1/2Nb1/2)–Pb(Mg1/3Nb2/3)O3–PbTiO3 (Mn:PIN–PMN–PT) single crystals has been observed in situ under a polarized light microscope. Furthermore, the anisotropic temperature–electric field phase diagrams are established based on microscopic domain observation and macroscopic dielectric and strain behavior. The temperature-induced phase transitions of [100]- and [111]-poled crystals both follow the sequence rhombohedral (R)–tetragonal (T)–cubic (C). However, [110]-poled crystals undergo an R–orthorhombic (O)–T–C process upon heating. The electric field-induced phase transitions originate from the noncollinearity of the direction of the electric field and the polarization vector, such as R–T with E||[100] direction, R–O and T–O with E||[110] direction and T–R with E||[111] direction. Moreover, the ultrahigh piezoelectric activity is closely related to the field-induced phase transitions, particularly the transformations with low threshold field. By the thermodynamic theory analysis, the phase boundaries contribute to the globally flattened free energy profile, resulting in an enhanced piezoelectric response. Our results are beneficial to further understanding the structure/properties relationship in Mn:PIN–PMN–PT single crystals for applications in high-temperature and high-power devices.
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- 2018
132. Modeling the electron density distribution of high-enthalpy plasma jets through chemical reaction method
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Yuan Wang, Xiaoping Li, Donglin Liu, Yanming Liu, Jiahao Xu, and Weimin Bao
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Condensed Matter Physics - Published
- 2021
133. Remodeling endogenous H2S microenvironment in colon cancer to enhance chemodynamic therapy
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Lu An, Ying Wan, Qiwei Tian, Xuesu Zhou, Gang Huang, Liu Mengjun, Shiping Yang, and Donglin Liu
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Tumor microenvironment ,Chemistry ,Colorectal cancer ,General Chemical Engineering ,High selectivity ,Endogeny ,02 engineering and technology ,General Chemistry ,Photothermal therapy ,equipment and supplies ,010402 general chemistry ,021001 nanoscience & nanotechnology ,medicine.disease ,01 natural sciences ,Industrial and Manufacturing Engineering ,In vitro ,0104 chemical sciences ,In vivo ,Cancer research ,medicine ,Environmental Chemistry ,0210 nano-technology - Abstract
Chemodynamic therapy (CDT) is a newly emerged, minimally invasive treatment with high selectivity, few side effects, and good prospects for clinical application. However, CDT does not effectively inhibit the growth of colon cancer, which has a strongly reducing tumor microenvironment owing to a high endogenous expression of H2S. To overcome this limitation, a new strategy is proposed to enhance the CDT of colon cancer by remodeling the microenvironment through depletion of endogenous H2S by CuFe2O4 nanoparticles. After H2S depletion, the valence of Cu (II) and Fe (III) in CuFe2O4 particles is reduced to Cu (I) and Fe (II) and photothermal properties of the nanoparticles are activated, both these effects enhance CDT. Further, in vitro and in vivo results demonstrate that endogenous H2S depletion by CuFe2O4 particles induced three effects that synergistically enhanced the performance of CDT. In this study, the development of a new strategy to enhance the CDT of colon cancer is reported.
- Published
- 2021
134. Combination Therapy with Bispecific Antibodies and PD-1 Blockade Enhances the Antitumor Potency of T Cells
- Author
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Rongxiu Li, David M. Goldenberg, Thomas M. Cardillo, Yang Wang, Donglin Liu, Chien-Hsing Chang, Diane L. Rossi, and Edmund A. Rossi
- Subjects
Cytotoxicity, Immunologic ,0301 basic medicine ,Cancer Research ,T-Lymphocytes ,medicine.medical_treatment ,Programmed Cell Death 1 Receptor ,Apoptosis ,Triple Negative Breast Neoplasms ,Mice, SCID ,GPI-Linked Proteins ,Peripheral blood mononuclear cell ,Mice ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Antigens, Neoplasm ,Mice, Inbred NOD ,In vivo ,Antibodies, Bispecific ,Tumor Cells, Cultured ,Animals ,Humans ,Medicine ,Cell Proliferation ,Tumor microenvironment ,biology ,business.industry ,Immunotherapy ,Xenograft Model Antitumor Assays ,Carcinoembryonic Antigen ,030104 developmental biology ,Oncology ,chemistry ,Cell culture ,030220 oncology & carcinogenesis ,Immunology ,Cancer cell ,Leukocytes, Mononuclear ,biology.protein ,Cancer research ,Female ,Antibody ,Growth inhibition ,business ,Cell Adhesion Molecules - Abstract
The DOCK-AND-LOCK (DNL) method is a platform technology that combines recombinant engineering and site-specific conjugation to create multispecific, multivalent antibodies of defined composition with retained bioactivity. We have applied DNL to generate a novel class of trivalent bispecific antibodies (bsAb), each comprising an anti-CD3 scFv covalently conjugated to a stabilized dimer of different antitumor Fabs. Here, we report the further characterization of two such constructs, (E1)-3s and (14)-3s, which activate T cells and target Trop-2– and CEACAM5-expressing cancer cells, respectively. (E1)-3s and (14)-3s, in the presence of human T cells, killed target cells grown as monolayers at subnanomolar concentrations, with a similar potency observed for drug-resistant cells. Antitumor efficacy was demonstrated for (E1)-3s coadministered with human peripheral blood mononuclear cells (PBMC) in NOD/SCID mice harboring xenografts of MDA-MB-231, a triple-negative breast cancer line constitutively expressing Trop-2 and PD-L1. Growth inhibition was observed following treatment with (E1)-3s or (14)-3s combined with human PBMC in 3D spheroids generated from target cell lines to mimic the in vivo behavior and microenvironment of these tumors. Moreover, addition of an antagonistic anti–PD-1 antibody increased cell death in 3D spheroids and extended survival of MDA-MB-231-bearing mice. These preclinical results emphasize the potential of combining T-cell–redirecting bsAbs with antagonists or agonists that mitigate T-cell inhibition within the tumor microenvironment to improve immunotherapy of solid cancers in patients. They also support the use of 3D spheroids as a predictive alternative to in vivo models for evaluating T-cell functions. Cancer Res; 77(19); 5384–94. ©2017 AACR.
- Published
- 2017
135. Attenuation of low-frequency electromagnetic wave in the thin sheath enveloping a high-speed vehicle upon re-entry.
- Author
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DongLin Liu, XiaoPing Li, YanMing Liu, Kai Xie, and BoWen Bai
- Subjects
- *
ELECTROMAGNETIC compatibility , *SHEATH folds (Geology) , *IONOSPHERE , *ATMOSPHERIC physics , *ELECTRON density - Abstract
Low-frequency (LF) electromagnetic (EM) waves are suggested as potentially solving "radio blackout" caused by a plasma sheath enveloping a high-speed vehicle on re-entry. However, the traditional plasma absorption theory neglects the fact that the plasma sheath is electrically small compared to LF EM wavelengths. To understand clearly the attenuation of such waves through the plasma sheath, different attenuation mechanisms for the electric field (SE) and magnetic field (SH) were studied using the equivalent circuit approach. Analytical expressions were derived by modeling the plasma sheath as a spherical shell, and numerical simulations were performed to validate the effectiveness of the expressions. SE and SH are calculated for various plasma parameter settings; the EM wave attenuations obtained from plasma absorption theory are used for comparison. Results show that, instead of SE and SH being equal in the plasma absorption theory, SE and SH are no longer the same for electrically small sizes. Whereas |SH| is close to that from plasma absorption theory, |SE| is much higher. Further analysis shows that |SH| is a function of the ratio of electron density (ne) and collision frequency (ve) and increases with increasing ne/ve. Numerical simulations with radio-attenuation-measurement-C-like vehicle's plasma sheath parameters are performed and the results show that the magnetic field attenuation in the front part of the vehicle is much lower than in the rear. So it is suggested to place the magnetic loop antenna in the very front part of the vehicle. Finally, SH at different frequencies are calculated using plasma sheath parameter values simulating the re-entry phase of a radio-attenuation measurement-C vehicle and results show that such a vehicle might overcome radio blackout during the entire re-entry phase if systems operating below 3MHz and above the L-band are combined with a lower-frequency system working below Earth's ionosphere and a higher-frequency system working above the Earth's ionosphere. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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- View/download PDF
136. Design and implementation of webGIS-based GPS vehicle monitoring system
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Qimin, Cheng, Chongjun, Yang, Zhenfeng, Shao, Donglin, Liu, and Liang, Gao
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- 2004
- Full Text
- View/download PDF
137. Research on the method of dual-frequency microwave diagnosis of plasma for solving phase integer ambiguity
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Xiaoping LI, Chengwei ZHAO, Yanming LIU, Jiahui ZHANG, Donglin LIU, Chao SUN, and Weimin BAO
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Materials science ,Phase (waves) ,Dual frequency ,Plasma ,Integer ambiguity ,Condensed Matter Physics ,Microwave ,Computational physics - Published
- 2021
138. Effects of pulsed magnetic field on density reduction of high flow velocity plasma sheath
- Author
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Xiaoping Li, Yuan Wang, Jiahao Xu, and Donglin Liu
- Subjects
Debye sheath ,symbols.namesake ,Materials science ,Physics::Plasma Physics ,Density reduction ,Physics::Space Physics ,symbols ,Condensed Matter Physics ,High flow ,Molecular physics ,Magnetic field - Abstract
A three-dimensional model is proposed in this paper to study the effect of the pulsed magnetic field on the density distribution of high flow velocity plasma sheath. Taking the typical parameters of plasma sheath at the height of 71 km as an example, the distribution characteristics and time evolution characteristics of plasma density in the flow field under the action of pulsed magnetic field, as well as the effect of self-electric field on the distribution of plasma density, are studied. The simulation results show that pulsed magnetic field can effectively reduce the density of plasma sheath. Meanwhile, the simulation results of three-dimensional plasma density distribution show that the size of the density reduction area is large enough to meet the communication requirements of the Global Position System (GPS) signal. Besides, the location of density reduction area provides a reference for the appropriate location of antenna. The time evolution of plasma density shows that the effective density reduction time can reach 62% of the pulse duration, and the maximum reduction of plasma density can reach 55%. Based on the simulation results, the mechanism of the interaction between pulsed magnetic field and plasma flow field is physically analyzed. Furthermore, the simulation results indicate that the density distributions of electrons and ions are consistent under the action of plasma self-electric field. However, the quasi neutral assumption of plasma in the flow field is not appropriate, because the self-electric field of plasma will weaken the effect of the pulsed magnetic field on the reduction of electron density, which cannot be ignored. The calculation results could provide useful information for the mitigation of communication blackout in hypersonic vehicles.
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- 2021
139. Method for increasing upper limit of heat flux measurement of slug calorimeter in high enthalpy plasma jet
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Donglin Liu, Yanming Liu, Yuan Wang, and Xiaoping Li
- Subjects
010302 applied physics ,Jet (fluid) ,Materials science ,Physics ,QC1-999 ,Enthalpy ,General Physics and Astronomy ,Response time ,02 engineering and technology ,Mechanics ,021001 nanoscience & nanotechnology ,Residence time (fluid dynamics) ,01 natural sciences ,Calorimeter ,Heat flux ,0103 physical sciences ,Melting point ,Transient (oscillation) ,0210 nano-technology - Abstract
The temperature of the high-power inductively coupled plasma jet is very high, and its temperature is difficult to measure directly. The heat flux becomes a thermodynamic characteristic to measure the plasma jet. The existing heat flux calculation method is based on the temperature change rate after the response time. The slug is required to stay in the high enthalpy jet area for a longer time. With the slug temperature reaching the melting point as the upper limit, the shorter the residence time, the greater the upper limit of the measured heat flux. In this paper, the first-order transient solution is added to the steady-state solution of temperature (the calculation equation of the existing method), which can shorten the response time. The shortening of the response time can reduce the residence time of the slug in the jet region, and the reduction in the residence time can increase the upper limit of the calorimeter heat flux measurement. This paper uses numerical simulation and experimental methods to verify that the steady-state solution method and the first-order transient solution method can obtain consistent heat flux results. Using the first-order transient solution method can reduce the residence time of the slug calorimeter in the jet region. According to the shortening of the residence time, the method of using the first-order transient solution can increase the upper limit of the heat flux measurement by more than 25%.
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- 2021
140. Density reduction on plasma sheath using pulsed magnetic field
- Author
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Cong Xu, Xiaoping Li, Qin Yongqiang, Jiahao Xu, and Donglin Liu
- Subjects
Physics ,Electron density ,Hypersonic speed ,Debye sheath ,Rotational symmetry ,Plasma ,Condensed Matter Physics ,01 natural sciences ,010305 fluids & plasmas ,Computational physics ,Magnetic field ,symbols.namesake ,Transmission (telecommunications) ,Physics::Plasma Physics ,Physics::Space Physics ,0103 physical sciences ,symbols ,010306 general physics ,Space vehicle - Abstract
When a space vehicle travels through the atmosphere at a hypersonic speed, it is enveloped by a plasma sheath. The density of plasma sheath is high enough such that communication and telemetry signals are prevented from passing to and from the vehicle, which is called communication blackout. A method to reduce plasma density for communication blackout mitigation by using pulsed magnetic field is proposed in this paper. In order to study the effect of pulsed magnetic field on plasma density, a two-dimensional axisymmetric model was established. The simulation results suggested that the pulsed magnetic field can reduce the plasma sheath density of 5 cm thickness by more than 90%, and was of sufficient size (about 5 cm) and time duration (about 330 μs) to permit transmission of data. On the basis of the simulation results, the interaction mechanism between pulsed magnetic field and plasma is explained by theoretical analysis. Furthermore, experiments of the plasma density reduction by pulsed magnetic field are performed. The experimental results suggested that a 0.55T pulsed magnetic field can reduce the plasma sheath density of 14 cm thickness by 43 % – 78 %, which verifies the effectiveness of the pulsed magnetic field method. A comparison of results from simulation and experiment provided strong evidence for the correctness of the simulation model. The simulation results also show that low pressure and high initial electron density are beneficial to the reduction of plasma density, which also explains the phenomenon in the experiment. In addition, it is found in the experiment that two continuous reverse pulses can play the same role in reducing the plasma density, which provides the possibility for the continuous reduction of plasma density. These investigations could have a significant benefit on the design and optimization of pulsed magnetic field mitigation scheme for the blackout problem.
- Published
- 2021
141. Symbol error rate on fading self-interference channel in full-duplex
- Author
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Youxi Tang, Fei Wu, and Donglin Liu
- Subjects
Computer science ,business.industry ,Orthogonal frequency-division multiplexing ,020206 networking & telecommunications ,02 engineering and technology ,Residual ,03 medical and health sciences ,symbols.namesake ,0302 clinical medicine ,0202 electrical engineering, electronic engineering, information engineering ,symbols ,Fading ,Electrical and Electronic Engineering ,Symbol rate ,Telecommunications ,business ,Doppler effect ,Algorithm ,030217 neurology & neurosurgery ,Coding (social sciences) ,Communication channel ,Data transmission - Abstract
In-band full-duplex (FD) is being considered as a promising technology for the next generation wireless communication systems. In this paper, the performance of orthogonal frequency division multiplexing (OFDM) modulation system with different symbol duration and the code spreading system with different spreading sequence lengths under time-varying self-interference (SI) channel in FD mode is investigated respectively. Typically, the SI channel is estimated during the SI cancellation duration and used for SI suppression in the whole data transmission duration. First, the expressions of the residual SI power during the data transmission duration are derived under the classical, the uniform, and the two-way Doppler SI channels. Second, the signal-to-interference-and-noise-ratio after the SI mitigation is obtained. Third, the symbol error rates for the OFDM modulation and the code spreading systems are given. Simulation results show that OFDM symbol length should be selected longer when the symbol duration is significantly lower than the SI coherent time while the length of the coding spreading system should be chosen shorter.
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- 2017
142. On the Analog Self-Interference Cancellation for Full-Duplex Communications With Imperfect Channel State Information
- Author
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Shihai Shao, Youxi Tang, Ying Shen, Yi Gong, and Donglin Liu
- Subjects
General Computer Science ,02 engineering and technology ,Residual ,symbols.namesake ,0203 mechanical engineering ,Control theory ,Full duplex ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,General Materials Science ,channel state information ,Computer Science::Information Theory ,Physics ,Dynamic range ,General Engineering ,Linearity ,020206 networking & telecommunications ,020302 automobile design & engineering ,time-varying channels ,self-interference cancellation ,Power (physics) ,Channel state information ,symbols ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,Transceiver ,Doppler effect ,Sensitivity (electronics) ,lcsh:TK1-9971 - Abstract
This paper studies the performance of the analog multi-tap (MT) canceller, where the tap coefficients are calculated based on the estimated self-interference (SI) channel state information (CSI). In this paper, both the time-invariant and the time-varying SI channels scenarios are investigated, considering the dynamic range of the analog-to-digital converter (ADC) and the linearity of the receiver chain. Closed-form expressions are first developed to calculate the residual SI power after the MT cancellation, characterizing the joint effects of the imperfect SI CSI, reconstruction errors on the estimated SI CSI, and the variation of the SI channels. Then, the achievable rate of the full-duplex transceivers is derived as a function of the residual SI power after the MT cancellation, dynamic range of the ADC, and the linearity of the receiver chain. Theoretical and simulated results show that with imperfect SI CSI, deploying more taps may harm the amount of analog SI cancellation. The sensitivity of the canceller to the doppler frequency shift reduces the amount of analog SI cancellation, and thus brings rate gain loss even with a doppler negligible in conventional communications.
- Published
- 2017
143. Research and Application of FAHP in Bidding Quotation for Petroleum Geophysical Prospecting Project
- Author
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Jianhe Guan, Jing Wang, and Donglin Liu
- Subjects
Fuzzy analytic hierarchy process ,Operations research ,Computer science ,05 social sciences ,050401 social sciences methods ,Analytic hierarchy process ,Bidding ,01 natural sciences ,Fuzzy logic ,010104 statistics & probability ,0504 sociology ,Hierarchical analysis ,Fuzzy matrix ,Evaluation methods ,0101 mathematics ,Geophysical prospecting - Abstract
This paper mainly talks about the main layer analytical method, and fuzzy comprehensive evaluation, fuzzy hierarchical analysis (AHP) method of a deeper connotation, and further discusses its application in bidding quotation for petroleum geophysical prospecting project. Fuzzy analytic hierarchy process (FAHP) integrates many merits of AHP and fuzzy comprehensive evaluation organically. It determines the weight of each affecting factor using analytic hierarchy process at first, and then uses the fuzzy comprehensive evaluation method to determine each scheme index. FAHP can effectively enhance the decision-making efficiency.
- Published
- 2017
144. Co-expression analysis reveals dysregulated miRNAs and miRNA-mRNA interactions in the development of contrast-induced acute kidney injury
- Author
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Weiwei Bao, Zhiqing Wang, Zhurong Luo, Hao Chen, Donglin Liu, Cancan Lai, Ping Tan, Mingfang Huang, and Xiaobiao Zou
- Subjects
0301 basic medicine ,Transcription, Genetic ,Molecular biology ,Contrast Media ,Pathogenesis ,030204 cardiovascular system & hematology ,Pathology and Laboratory Medicine ,Kidney ,Biochemistry ,0302 clinical medicine ,Sequencing techniques ,Cell Signaling ,Gene expression ,Medicine and Health Sciences ,WNT Signaling Cascade ,Multidisciplinary ,Small nuclear RNA ,Messenger RNA ,Acute kidney injury ,RNA sequencing ,Acute Kidney Injury ,Signaling Cascades ,Reverse transcription polymerase chain reaction ,Nucleic acids ,Small nucleolar RNA ,Medicine ,Anatomy ,Research Article ,Signal Transduction ,Science ,Biology ,Deep sequencing ,03 medical and health sciences ,microRNA ,medicine ,Genetics ,Animals ,RNA, Messenger ,Non-coding RNA ,Natural antisense transcripts ,Biology and life sciences ,Kidney metabolism ,Kidneys ,Renal System ,Cell Biology ,medicine.disease ,Fold change ,Gene regulation ,Rats ,Research and analysis methods ,MicroRNAs ,Disease Models, Animal ,030104 developmental biology ,Molecular biology techniques ,Gene Expression Regulation ,Cancer research ,RNA - Abstract
The pathogenesis of contrast-induced acute kidney injury (CI-AKI) is incompletely understood. MicroRNAs (miRNAs) are important mediators that normally function via post-transcriptional degradation of target mRNAs. Emerging evidence indicates the appearance of differentially expressed (DE) miRNAs in CI-AKI following the injection of intravenous contrast medium. However, there are differences in the pathological mechanism and incidence of CI-AKI between intravenous and intra-arterial contrast administration. The present study aimed to investigate the critical roles of dysregulated miRNAs and their associated mRNAs in kidney injury following intra-arterial contrast medium exposure. Based on a reliable CI-AKI rat model, we conducted genome-wide miRNA and mRNA expression profiling analysis using deep sequencing. In the study, 36 DE mature miRNAs were identified (fold change > 1.5 and p value < 0.05) in the kidneys of CI-AKI rats (n = 3) compared with that in the controls (n = 3), consisting of 23 up-regulated and 13 down-regulated DE miRNAs. Bioinformatic analysis revealed that wingnut (Wnt), transforming growth factor beta (TGF-β), and 5'-AMP-activated protein kinase (AMPK) signaling pathways were most likely to be modulated by these dysregulated miRNAs. Around 453 dysregulated genes (fold change > 2.0 and p value < 0.05) were identified. Integrated analysis revealed 2037 putative miRNA-mRNA pairs with negative correlations. Among them, 6 DE miRNAs and 13 genes were selected for further quantitative real-time reverse transcription polymerase chain reaction validation (n = 6 for each group), and a good correspondence between the two techniques was observed. In conclusion, the present study provided evidence of miRNA-mRNA interactions in the development of kidney injury following an intra-arterial contrast injection. These findings provide insights into the underlying mechanisms of CI-AKI.
- Published
- 2019
145. A Cluster of Bunyavirus-Associated Severe Fever With Thrombocytopenia Syndrome Cases in a Coastal Plain Area in China, 2015: Identification of a Previously Unidentified Endemic Region for Severe Fever With Thrombocytopenia Bunyavirus
- Author
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Lunbiao Cui, Jianli Hu, Jia-Ping Cai, Fengcai Zhu, Zhifeng Li, Xilin Guo, Xuefeng Zhang, Changjun Bao, Donglin Liu, Yufu Zhang, Renjie Jiang, Jinjin Shen, and Dapeng Liu
- Subjects
0301 basic medicine ,Veterinary medicine ,Fulminant ,030231 tropical medicine ,Tick ,Disease cluster ,Orthobunyavirus ,law.invention ,03 medical and health sciences ,0302 clinical medicine ,Human-to-human transmission ,law ,medicine ,Major Article ,Polymerase chain reaction ,biology ,business.industry ,Transmission (medicine) ,Severe fever with thrombocytopenia syndrome (SFTS) ,medicine.disease ,biology.organism_classification ,Severe fever with thrombocytopenia syndrome ,030104 developmental biology ,Infectious Diseases ,Oncology ,Bunyavirus ,Haemaphysalis longicornis ,business ,Endemic region - Abstract
Background Severe fever with thrombocytopenia syndrome (SFTS) is a typical tick-borne, natural focal disease. The natural foci of SFTS were considered to exist in hilly and mountainous areas before 2015. A cluster of 3 patients exposed to a patient with a fulminant disease consistent with SFTS occurred from July to August 2015 in Dongtai County, which is characterized by alluvial plains; this prompted investigation. Methods The epidemiological, clinical, and laboratory features of 4 patients in the cluster were analyzed. Serum samples from the indigenous healthy population and native domesticated animals were collected to conduct laboratory tests, along with small wild animals and ticks. Results In 3 secondary case patients, high fever, thrombocytopenia and leukopenia developed within 8–13 days after contact with blood or bloody secretions from the index patient; SFTS was then diagnosed by means of reverse-transcription polymerase chain reaction. Genomic sequencing and analysis of S and L segments of 2 viral strains isolated from 2 secondary case patients showed that they shared 99.8%–99.9% homology in nucleotide sequence. The seroprevalences among indigenous healthy population, native livestock, native poultry, and small wild animals was 0.74%, 17.54%, 6.67%, and 1.12%, respectively. Three questing ticks, 61 feeding ticks, and 178 small wild animals were collected in August 2015. Survey on tick density and seasonal fluctuation in 2016 showed that ticks were active from March to October. All ticks were identified as Haemaphysalis longicornis. Severe fever with thrombocytopenia bunyavirus (SFTSV)–specific RNA was detected in the ticks collected in 2016, and the minimum SFTSV infection rate in these ticks was 0.54% (1 of 185).Wild mammals and ticks collected in August 2015 tested negative for SFTSV-specific RNA. Conclusions Aside from hilly or mountainous area, a coastal plain was identified as the natural foci of SFTSV in Dongtai County, China. The involvement of migration in the evolution of SFTSV might lead to a transregional transmission event of SFTSV., A cluster of patients with severe fever with thrombocytopenia syndrome was identified in Dongtai County from July to August 2015, suggesting that the natural foci of severe fever with thrombocytopenia bunyavirus (SFTSV) are not limited to hilly or mountainous areas. A transregional SFTSV transmission event occurred in the cluster, further evidence of migration in the evolution of SFTSV.
- Published
- 2019
146. Spontaneous breathing in patients with severe acute respiratory distress syndrome receiving prolonged extracorporeal membrane oxygenation
- Author
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Lijuan Wu, Xu Huang, Guohui Fan, Li Yi, Min Li, Donglin Liu, Qingyuan Zhan, Sichao Gu, and Jingen Xia
- Subjects
Pulmonary and Respiratory Medicine ,Adult ,Male ,ARDS ,Time Factors ,Respiratory rate ,medicine.medical_treatment ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Mechanical ventilation ,Heart rate ,medicine ,Extracorporeal membrane oxygenation ,Humans ,Hospital Mortality ,Spontaneous breathing ,Acute respiratory distress syndrome ,Retrospective Studies ,lcsh:RC705-779 ,Respiratory Distress Syndrome ,Lung ,business.industry ,Respiration ,030208 emergency & critical care medicine ,lcsh:Diseases of the respiratory system ,Recovery of Function ,Length of Stay ,Middle Aged ,medicine.disease ,Respiration, Artificial ,Intensive Care Units ,medicine.anatomical_structure ,surgical procedures, operative ,Treatment Outcome ,030228 respiratory system ,Anesthesia ,Cohort ,Breathing ,Airway Extubation ,Female ,business ,Research Article - Abstract
Background The use of extracorporeal membrane oxygenation (ECMO) in awake, spontaneously breathing and non-intubated patients (awake ECMO) may be a novel therapeutic strategy for severe acute respiratory distress syndrome (ARDS) patients. The purpose of this study is to assess the feasibility and safety of awake ECMO in severe ARDS patients receiving prolonged ECMO (> 14 days). Methods We describe our experience with 12 consecutive severe ARDS patients (age, 39.1 ± 16.4 years) supported with awake ECMO to wait for native lung recovery during prolonged ECMO treatment from July 2013 to January 2018. Outcomes are reported including the hospital mortality, ECMO-related complications and physiological data on weaning from invasive ventilation. Results The patients received median 26.0 (15.5, 64.8) days of total ECMO duration in the cohort. The longest ECMO support duration was 121 days. Awake ECMO and extubation was implemented after median 10.2(5.0, 42.9) days of ECMO. Awake ECMO was not associated with increased morbidity. The total invasive ventilation duration, lengths of stay in the ICU and hospital in the cohort were 14.0(12.0, 37.3) days, 33.0(22.3, 56.5) days and 46.5(27.3, 84.8) days, respectively. The hospital mortality rate was 33.3% (4/12) in the cohort. Survivors had more stable respiratory rate and heart rate after extubation when compared to the non-survivors. Conclusions With carefully selected patients, awake ECMO is a feasible and safe strategy for severe pulmonary ARDS patients receiving prolonged ECMO support to wait for native lung recovery.
- Published
- 2018
147. Abnormal Anionic Porphyrin Sensing Effect for HER2 Gene Related DNA Detection via Impedance Difference between MWCNTs and Single-Stranded DNA or Double-Stranded DNA
- Author
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Min Wang, Liu Long, Jingheng Ning, Jianhui Wang, Hou Rong, Donger Chen, Donglin Liu, and Xin Luo
- Subjects
Anions ,Porphyrins ,anionic porphyrin ,Receptor, ErbB-2 ,bioanalysis ,Stacking ,DNA sensor ,Pharmaceutical Science ,DNA, Single-Stranded ,02 engineering and technology ,Carbon nanotube ,Biosensing Techniques ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,Article ,Analytical Chemistry ,law.invention ,lcsh:QD241-441 ,chemistry.chemical_compound ,lcsh:Organic chemistry ,law ,Limit of Detection ,Neoplasms ,Drug Discovery ,polycyclic compounds ,Humans ,Physical and Theoretical Chemistry ,Chemistry ,Nanotubes, Carbon ,Organic Chemistry ,HER2 gene ,021001 nanoscience & nanotechnology ,Porphyrin ,Combinatorial chemistry ,0104 chemical sciences ,Dielectric spectroscopy ,Electrochemical gas sensor ,electrochemical impedance spectroscopy ,Chemistry (miscellaneous) ,Dielectric Spectroscopy ,Electrode ,Molecular Medicine ,0210 nano-technology ,DNA - Abstract
Human epidermal growth factor receptor 2 (HER2) is a key tumor marker for several common and deadly cancers. It is of great importance to develop efficient detection methods for its over-expression. In this work, an electrochemical impedance spectroscopy (EIS) method adjustable by anionic porphyrin for HER2 gene detection has been proposed, based on the impedance difference between multi-walled carbon nanotubes (MWCNTs) and DNA. The interesting finding herein is that with the addition of anionic porphyrin, i.e., meso-tetra(4-sulfophenyl)-porphyrin (TSPP), the impedance value obtained at a glass carbon electrode (GCE) modified with MWCNTs and a single stranded DNA (ssDNA), the probe DNA that might be assembled tightly onto MWCNTs through &pi, &pi, stacking interaction, gets a slight decrease, however, the impedance value from a GCE modified with MWCNTs and a double stranded DNA (dsDNA), the hybrid of the probe DNA with a target DNA, which might be assembled loosely onto MWCNTs for the screening effect of phosphate backbones in dsDNA, gets an obvious decrease. The reason may be that on the one hand, being rich in negative sulfonate groups, TSPP will try to push DNA far away from CNTs surface due to its strong electrostatic repulsion towards DNA, on the other hand, rich in planar phenyl or pyrrole rings, TSPP will compete with DNA for the surface of CNTs since it can also be assembled onto CNTs through conjugative interactions. In this way, the &ldquo, loosely assembled&rdquo, dsDNA will be repelled by this anionic porphyrin and released off CNTs surface much more than the &ldquo, tightly assembled&rdquo, ssDNA, leading to a bigger difference in the impedance value between dsDNA and ssDNA. Thus, through the amplification effect of TSPP on the impedance difference, the perfectly matched target DNA could be easily determined by EIS without any label. Under the optimized experimental conditions, this electrochemical sensor shows an excellent linear response to target DNA in a concentration range of 2.0 ×, 10&minus, 11&ndash, 2.0 ×, 6 M with a limit of detection (LOD) of 6.34 ×, 11 M (S/N = 3). This abnormally sensitive electrochemical sensing performance resulting from anionic porphyrin for DNA sequences specific to HER2 gene will offer considerable promise for tumor diagnosis and treatment.
- Published
- 2018
- Full Text
- View/download PDF
148. Ultrasensitive Electrochemical Sensor Based on Polyelectrolyte Composite Film Decorated Glassy Carbon Electrode for Detection of Nitrite in Curing Food at Sub-Micromolar Level
- Author
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Jiaojiao Li, Xin Luo, Ning Jingheng, Donger Chen, Donglin Liu, Hou Rong, Min Wang, and Jianhui Wang
- Subjects
nitrite detection ,Materials science ,Pharmaceutical Science ,02 engineering and technology ,Electrochemistry ,01 natural sciences ,Article ,Analytical Chemistry ,lcsh:QD241-441 ,chemistry.chemical_compound ,lcsh:Organic chemistry ,polyelectrolyte composite film ,Drug Discovery ,Physical and Theoretical Chemistry ,Nitrite ,Electrodes ,Curing (chemistry) ,Nitrites ,010401 analytical chemistry ,Organic Chemistry ,Reproducibility of Results ,Electrochemical Techniques ,Hydrogen-Ion Concentration ,021001 nanoscience & nanotechnology ,Polyelectrolytes ,Polyelectrolyte ,cyclic voltammetry ,Carbon ,0104 chemical sciences ,Electrochemical gas sensor ,chemistry ,Chemical engineering ,Chemistry (miscellaneous) ,Electrode ,Molecular Medicine ,Differential pulse voltammetry ,Cyclic voltammetry ,0210 nano-technology ,differential pulse voltammetry - Abstract
To ensure food quality and safety, developing cost-effective, rapid and precision analytical techniques for quantitative detection of nitrite is highly desirable. Herein, a novel electrochemical sensor based on the sodium cellulose sulfate/poly (dimethyl diallyl ammonium chloride) (NaCS/PDMDAAC) composite film modified glass carbon electrode (NaCS/PDMDAAC/GCE) was proposed toward the detection of nitrite at sub-micromolar level, aiming to make full use of the inherent properties of individual component (biocompatible, low cost, good electrical conductivity for PDMDAAC, non-toxic, abundant raw materials, good film forming ability for NaCS) and synergistic enhancement effect. The NaCS/PDMDAAC/GCE was fabricated by a simple drop-casting method. Electrochemical behaviors of nitrite at NaCS/PDMDAAC/GCE were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimum conditions, the NaCS/PDMDAAC/GCE exhibits a wide linear response region of 4.0 ×, 10&minus, 8 mol·, L&minus, 1~1.5 ×, 4 mol·, 1 and a low detection 1imit of 43 nmol·, 1. The NaCS/PDMDAAC shows a synergetic enhancement effect toward the oxidation of nitrite, and the sensing performance is much better than the previous reports. Moreover, the NaCS/PDMDAAC also shows good stability and reproducibility. The NaCS/PDMDAAC/GCE was successfully applied to the determination of nitrite in ham sausage with satisfactory results.
- Published
- 2018
149. Ultrasmall Fe@Fe3O4 nanoparticles as T1–T2 dual-mode MRI contrast agents for targeted tumor imaging
- Author
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Qiwei Tian, Chengbin Wang, Jiaojiao Li, Shiping Yang, Jiaomin Lin, Donglin Liu, and An Lu
- Subjects
chemistry.chemical_classification ,Tumor imaging ,0303 health sciences ,media_common.quotation_subject ,Biomedical Engineering ,Dual mode ,Pharmaceutical Science ,Medicine (miscellaneous) ,Nanoparticle ,Bioengineering ,Peptide ,02 engineering and technology ,Conjugated system ,021001 nanoscience & nanotechnology ,In vitro ,03 medical and health sciences ,chemistry ,In vivo ,Molecular Medicine ,Contrast (vision) ,General Materials Science ,0210 nano-technology ,030304 developmental biology ,media_common ,Biomedical engineering - Abstract
Targeted T1–T2 MRI contrast agents, which can eliminate the difficulty of image matching across multiple imaging instruments and permit specific localization of lesions, are promising candidates for more accurate diagnosis of tumors. In this study, ultrasmall Fe@Fe3O4 nanoparticles were designed and synthesized as T1–T2 dual-mode MRI contrast agents for accurate tumor imaging. First, to investigate the influence of nanoparticle size, Fe@Fe3O4 nanoparticles with diameters of 4, 8, and 12 nm were prepared, among which the 8 nm 3-(3,4-dihydroxyphenyl)propionic acid (DHCA)-modified nanoparticles exhibited the optimal T1–T2 dual-mode MRI performance. Next, to develop a tumor-targeted contrast agent, the DHCA-Fe@Fe3O4 nanoparticles were conjugated with the F56 peptide, which targets the vascular endothelial growth factor receptor, and the resulting F56-DHCA-Fe@Fe3O4 nanoparticles were found to exhibit good T1–T2 dual-mode imaging and tumor-targeting performance both in vitro and in vivo, indicating the nanoparticles represent a new research tool for accurate tumor diagnosis.
- Published
- 2021
150. Modelling of second mode positive streamer in cyclohexane by considering optimized electron saturation velocity
- Author
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Qiang Liu, Zhongdong Wang, and Donglin Liu
- Subjects
010302 applied physics ,Physics ,Acoustics and Ultrasonics ,Cyclohexane ,Saturation velocity ,High voltage ,Dielectric ,Electron ,Condensed Matter Physics ,01 natural sciences ,Acceleration voltage ,010305 fluids & plasmas ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Computational physics ,chemistry.chemical_compound ,chemistry ,0103 physical sciences ,Breakdown voltage ,Voltage - Abstract
Experimental and modelling study of the pre-breakdown phenomenon in dielectric liquids, generally called ‘streamers’, is vital for the application of liquids in high voltage and power dense devices. Streamer is characterized into four modes by average propagation velocity, among which the second mode streamer is responsible for breakdowns at a wide range of gap distances and voltage levels. The stable propagation velocity of around 2 km s−1 is one of the key characteristics of the second mode streamer. The most recent study found that streamer branching is not the main reason for the stable velocity of second mode streamer as was assumed previously. Besides, one major drawback of the existing charge-drift model of the second mode streamer is the over-estimation of electron velocity, which leads to the much higher streamer propagation velocity in simulation than that observed in experiments. In this paper, restriction of streamer propagaiton velocity by using electron saturation velocity (ESV) is found to be the key reason for the stable propagaiton velocity of the second mode streamer. The charge-drift model is modified by considering different ESVs. It is found that reducing ESV from 30 km s−1 to 2.5 km s−1 in simulation can greatly constrain positive streamer propagation velocity from 4.15 km s−1 to 0.50 km s−1 in cyclohexane. When ESV is set to be 7.5 km s−1 in cyclohexane, the streamer propagation velocity in simulation increases from 1.59 km s−1 at 80 kV (below breakdown voltage) to 1.91 km s−1 at 100 kV (near to acceleration voltage), which closely matches the experimental observations.
- Published
- 2021
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