54 results on '"Zhen-Xing Liu"'
Search Results
2. The evolving epidemiology of monkeypox virus
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Heng, Li, Hong, Zhang, Ke, Ding, Xiao-Hui, Wang, Gui-Yin, Sun, Zhen-Xing, Liu, and Yang, Luo
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Endocrinology, Diabetes and Metabolism ,Immunology ,Humans ,Immunology and Allergy ,Monkeypox ,Public Health ,Monkeypox virus ,General Biochemistry, Genetics and Molecular Biology - Abstract
Monkeypox, caused by the monkeypox virus (MPXV), is a zoonotic disease endemic mainly in West and Central Africa. As of 27 September 2022, human monkeypox has occurred in more than 100 countries (mostly in non-endemic regions) and caused over 66,000 confirmed cases, which differs from previous epidemics that mainly affected African countries. Due to the increasing number of confirmed cases worldwide, the World Health Organization (WHO) has declared the monkeypox outbreak as a Public Health Emergency of International Concern on July 23, 2022. The international outbreak of human monkeypox represents a novel route of transmission for MPXV, with genital lesions as the primary infection, and the emergence of monkeypox in the current outbreak is also new, as novel variants emerge. Clinical physicians and scientists should be aware of this emerging situation, which presents a different scenario from previous outbreaks. In this review, we will discuss the molecular virology, evasion of antiviral immunity, epidemiology, evolution, and detection of MPXV, as well as prophylaxis and treatment strategies for monkeypox. This review also emphasizes the integration of relevant epidemiological data with genomic surveillance data to obtain real-time data, which could formulate prevention and control measures to curb this outbreak.
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- 2022
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3. Microstructure and magnetic properties of FeAs with coarse-grain and nanocrystalline structure
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Yuan ZHOU, Yun-yan WANG, Yan-jie LIANG, Yi-wei ZHOU, Zhen-xing LIU, Cong PENG, Yong KE, and Xiao-bo MIN
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Materials Chemistry ,Metals and Alloys ,Geotechnical Engineering and Engineering Geology ,Condensed Matter Physics - Published
- 2022
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4. The land-scape of immune response to monkeypox virus
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Heng Li, Qi-Zhao Huang, Hong Zhang, Zhen-Xing Liu, Xiao-Hui Chen, Li-Lin Ye, and Yang Luo
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General Medicine ,General Biochemistry, Genetics and Molecular Biology - Abstract
Human monkeypox is a viral zoonotic smallpox-like disease caused by the monkeypox virus (MPXV) and has become the greatest public health threat in the genus Orthopoxvirus after smallpox was eradicated. The host immune response to MPXV plays an essential role in disease pathogenesis and clinical manifestations. MPXV infection leads to skin lesions with the genital area as the main feature in the current outbreak and triggers a strong immune response that results in sepsis, deep tissue abscess, severe respiratory disease, and injuries to multiple immune organs. Emerging evidence shows that the immunopathogenesis of MPXV infection is closely associated with impaired NK-cell function, lymphopenia, immune evasion, increased antibodies, increased blood monocytes and granulocytes, cytokine storm, inhibition of the host complement system, and antibody-dependent enhancement. In this overview, we discuss the immunopathology and immunopathogenesis of monkeypox to aid the development of novel immunotherapeutic strategies against monkeypox.
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- 2022
5. Analysis of the Influence of IQ Imbalance Demodulation on DEM Measurement of Satellite Millimeter-Wave InSAR
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Zhen-xing Liu
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Condensed Matter::Quantum Gases ,Physics ,Astrophysics::Instrumentation and Methods for Astrophysics ,Phase (waves) ,Elevation ,Interference (wave propagation) ,law.invention ,Amplitude ,law ,Extremely high frequency ,Interferometric synthetic aperture radar ,Demodulation ,Radar ,Remote sensing - Abstract
IQ imbalance is one of the main factors leading to the amplitude and phase consistency of millimeter wave radar channels, which will bring about the interferometric phase error of millimeter wave interferometric synthetic aperture radar (InSAR). In this paper, the problem of IQ imbalance of InSAR receiving channel is modeled and analyzed, the mathematical expressions of IQ imbalance error parameters and interference phase error are derived, the influence of IQ imbalance on interference phase error and elevation error is analyzed quantitatively, The analysis results are very useful the design of spaceborne millimeter wave InSAR system.
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- 2020
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6. Self-screening of the polarized electric field in wurtzite gallium nitride along [0001] direction
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Qiu-Ling Qiu, Shi-Xu Yang, Qian-Shu Wu, Cheng-Lang Li, Qi Zhang, Jin-Wei Zhang, Zhen-Xing Liu, Yuan-Tao Zhang, and Yang Liu
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General Physics and Astronomy - Abstract
The strong polarization effect of GaN-based materials is widely used in high-performance devices such as white-light-emitting diodes (white LEDs), high electron mobility transistors (HEMTs), and GaN polarization superjunctions. However, the current researches on the polarization mechanism of GaN-based materials are not sufficient. In this paper, we studied the influence of polarization on electric field and energy band characteristics of Ga-face GaN bulk materials by using a combination of theoretical analysis and semiconductor technology computer-aided design (TCAD) simulation. The self-screening effect in Ga-face bulk GaN under ideal and non-ideal conditions is studied respectively. We believe that the formation of high-density two-dimensional electron gas (2DEG) in GaN is the accumulation of screening charges. We also clarify the source and accumulation of the screening charges caused by the GaN self-screening effect in this paper and aim to guide the design and optimization of high-performance GaN-based devices.
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- 2022
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7. Deep Sequencing Reveals New Insights Into the Transcriptomic Response to Uva Radiation in the Heads ofDrosophila melanogasterMeigen, 1830 (Diptera: Drosophilidae)
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Chaoliang Lei, Zhi-Hui Zhu, Zhen-Xing Liu, Weihua Ma, Yong-Cheng Dong, and Li-Jun Zhou
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Genetics ,biology ,biology.organism_classification ,DNA sequencing ,Deep sequencing ,Transcriptome ,Insect Science ,Drosophilidae ,Gene expression ,sense organs ,Drosophila melanogaster ,KEGG ,Gene ,Ecology, Evolution, Behavior and Systematics - Abstract
Ultraviolet A (UVA) radiation is capable of inducing various types of physiological effects related to all macromolecules in insects. However, the molecular mechanisms of insect responses to UVA radiation are still poorly understood. Transcriptional regulation of the expression of UVA-responsive genes is a crucial part of insect responses to UVA radiation. This research used the model insect Drosophila melanogaster to test its transcriptional response to UVA radiation via RNA sequencing, and systematically analyzed the head gene-expression profiles between different time points (0, 0.5, and 1.0 h). In all, 1,678 differentially-expressed (DE) genes were detected via pairwise comparisons among three different RNA-Seq libraries. Most DE genes, down-regulated continually or at the end point, were classified into cluster (1) of significant model profiles. Furthermore, combined with KEGG/pathways and Gene ontology enrichment analysis, DE genes greatly related to stress and defense responses, metabolic process, and enriched in signaling pathways responding to UVA radiation. A subset of differentially-expressed genes were selected to verify the RNA-Seq results through quantitative real-time PCR; the results of quantitative real-time PCR analyses strongly correlated with the RNA-Seq data. The results provided the extensive genetic components and possible mechanisms for insect resistance/adaptation to UVA radiation.
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- 2018
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8. Effects of Uva Radiation on the Performance of Adults and the First Filial Generation of the Fruit FlyDrosophila melanogasterMeigen, 1830 (Diptera: Drosophilidae)
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Lijun Zhou, Weihua Ma, Chaoliang Lei, Zhen-Xing Liu, and Junli Zheng
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0106 biological sciences ,media_common.quotation_subject ,Zoology ,Insect ,medicine.disease_cause ,01 natural sciences ,Toxicology ,03 medical and health sciences ,0302 clinical medicine ,Drosophilidae ,medicine ,Irradiation ,Ecology, Evolution, Behavior and Systematics ,media_common ,biology ,fungi ,Longevity ,Fecundity ,biology.organism_classification ,010602 entomology ,Insect Science ,sense organs ,F1 hybrid ,Drosophila melanogaster ,030217 neurology & neurosurgery ,Oxidative stress - Abstract
Ultraviolet A (UVA) radiation (400–315 nm) is the major component of solar ultraviolet (UV) radiation that reaches the Earth's surface due to the role of the stratospheric ozone. UVA radiation can induce various types of negative effects in all organisms including insects, such as oxidative stress, cell death, and photo-receptor damage. The objective of this study was to further elucidate the biological effects of UVA radiation on diurnal insects. In the present study, the effects of UVA radiation on adult longevity and fecundity in a model diurnal insect, Drosophila melanogaster Meigen, 1830 (Diptera: Drosophilidae), irradiated at different UVA-exposure times and intensities were investigated, as well as the developmental duration and cumulative survival rate of the first filial generation. The longevity of adults exposed to relatively low-intensity UVA radiation was prolonged for both sexes, and there was a significant increase observed after exposure for 3 h/day. The results also showed that ...
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- 2016
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9. Double-layer structure of the crust beneath the Zhongdian arc, SW China: U–Pb geochronology and Hf isotope evidence
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Jian-Lin Chen, Ji-Feng Xu, Zhen-Xing Liu, Xiao-Xiao Huang, JiangBo Ren, Xiang-Dong Zhao, and Kang Cao
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Underplating ,Subduction ,020209 energy ,Partial melting ,Geochemistry ,Geology ,Crust ,02 engineering and technology ,010502 geochemistry & geophysics ,01 natural sciences ,Tectonics ,Oceanic crust ,Geochronology ,0202 electrical engineering, electronic engineering, information engineering ,Mafic ,Petrology ,0105 earth and related environmental sciences ,Earth-Surface Processes - Abstract
U–Pb ages and Hf isotopes of zircons in Late Triassic and Cretaceous intrusive rocks from the Zhongdian arc, SW China, are used to decipher the tectonic, magmatic, and metallogenic processes that occurred during this period. New U–Pb dating of zircons from Late Triassic porphyries yielded ages of ca. 216 Ma and eHf(t) values of −2.1 to +6.1. Combined with previous results, the data indicate that these Late Triassic rocks were most likely derived from a juvenile mafic lower-crust with minor old crust material. However, the Cretaceous granites (∼80 Ma) have lower eHf(t) values (−7.6 to −2.4) than the Late Triassic rocks, indicating that the former originated from old crust. Based on the new data and previous studies of Mesozoic magmatic activity, a plausible model for the tectono-magmatism and metallogenesis of the Zhongdian arc is proposed. The westwards subduction of the Ganzi–Litang oceanic crust began before ∼230 Ma, resulting in the formation of a juvenile lower crust beneath the Zhongdian arc due to the underplating of mafic arc magmas during ca. 230–216 Ma. At ca. 216 Ma, break-off or slab-tearing of the west-dipping Ganzi–Litang oceanic slab led to partial melting of the juvenile lower crust, which gave rise to Cu-bearing porphyries. In the Late Cretaceous, the Zhongdian arc probably underwent post-collision extension, triggering the partial melting of the old middle–upper crustal materials and producing various granites and related Mo–Cu deposits. According to this model, the crust beneath the Zhongdian arc probably has a double-layer structure, with older crust at shallow levels and juvenile crust at deeper levels.
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- 2016
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10. luxS/AI-2 Quorum Sensing Is Involved in Antimicrobial Susceptibility in Streptococcus agalactiae
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Hao Ke, Yan Ping Ma, Zhen Xing Liu, Jiang Yao Ma, Yu Gu Li, Zhi Ling Liang, Hao Le, and Hu Cheng Yang
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Biofilm ,Antimicrobial susceptibility ,Aquatic Science ,Biology ,medicine.disease_cause ,Antimicrobial ,Estuarine fish ,Microbiology ,Multiple drug resistance ,Quorum sensing ,Streptococcus agalactiae ,medicine ,Animal Science and Zoology ,Pathogen - Abstract
Streptococcus agalactiae is an important pathogen in humans, cows, fish and so on, which causes pneumo-nia, sepsis, meningitis and sometimes death in human and mastitis in cows. In fish, S. agalactiae can result in massive kills of fish and is responsible for heavy eco-nomic losses in many species of freshwater, marine, and estuarine fish worldwide. Many reports showed that the infections characterized by septicemia and men-ingoencephalitis (Evans et al., 2002, 2006; Mian et al., 2009; Geng et al., 2012; Delannoy et al., 2013). Now, many antimicrobials have routinely been the drugs for prophylactic strategies and treatment of the infections of S. agalactiae. But, more and more multidrug resistant strains represent a critical challenge for antimicrobial therapy.Quorum sensing (QS) is a cell-cell communication mechanism to coordinate social activities. It is well known that one QS signal called autoinducer-2 (AI-2) is shared by both Gram-positive and Gram-negative bacte-ria (Bassler, 1999; Miller and Bassler, 2001; Waters and Bassler, 2005; Federle, 2009; Zhao et al., 2010; Wang et al., 2011). AI-2 molecule is formed as a result of spontaneous rearrangement of dihydroxy-2,3-pentanedi-one (DPD), which is catalyzed by the conserved and widespread luxS enzyme (Chen et al., 2002; Xavier and Bassler, 2003). Many studies have highlighted the sig-nificance of luxS/AI-2 in the biological processes of vari-ous bacterial species including antimicrobial production, biofilm formation, carbohydrate metabolism and viru-lence expression and so on (Bassler et al., 1993; Vendeville et al., 2005; Doherty et al., 2006; Ahmed et al., 2007, 2009; Choi et al., 2007; Palaniyandi et al., 2013).Interestingly, S. agalactiae also possesses a func-tional luxS gene and has the ability to produce AI-2 molecule. Analysis of 3D structure showed that deduced LuxS protein contained conserved active cen-ter (His-57, His-61, Cys-127) and Zn
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- 2015
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11. Core–shell CdS:Ga–ZnTe:Sb p–n nano-heterojunctions: fabrication and optoelectronic characteristics
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Yongqiang Yu, Ran Chen, Xu Ma, Hong-Wei Song, Yan Zhang, Li Wang, Zhen-Xing Liu, Qiang Li, Chunyan Wu, Lin-Bao Luo, and Jigang Hu
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Fabrication ,Materials science ,business.industry ,Nanowire ,Photodetector ,Nanotechnology ,Heterojunction ,General Chemistry ,Responsivity ,Absorption edge ,Nano ,Materials Chemistry ,Optoelectronics ,Coaxial ,business - Abstract
In this study, we reported on the construction of p–n junctions based on crystalline Ga-doped CdS–polycrystalline ZnTe nanostructures (NSs) for optoelectronic device application. The coaxial nano-heterojunction was fabricated by a two-step growth method. It is found that the absorption edge of CdS:Ga–ZnTe:Sb core–shell NSs red shifted to about 580 nm, compared with CdS nanowires (520 nm). The as-fabricated core–shell p–n junction exhibited obvious rectification characteristics with a low turn-on voltage of ∼0.25 V. What is more, it showed stable and repeatable photoresponse to 638 nm light illumination, with a responsivity and a detectivity of 1.55 × 103 A W−1 and 8.7 × 1013 cm Hz1/2 W−1, respectively, much higher than other photodetectors with similar device configurations. The generality of this study suggests that the present coaxial CdS:Ga–ZnTe:Sb core–shell nano-heterojunction will have great potential applications in future nano-optoelectronic devices.
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- 2015
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12. Gear Fault Diagnosis Based on Continuous Wavelet Spectrum Slice
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Hua Yuan Huang, Yan Xia Li, Shi Qiu, Jun Cao, Zhen Xing Liu, Xiao Li Yin, Cheng Zhou Fan, and Meng Huang
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Discrete wavelet transform ,Engineering ,business.industry ,Stationary wavelet transform ,Second-generation wavelet transform ,Feature extraction ,General Medicine ,Wavelet packet decomposition ,Wavelet ,Continuous wavelet ,Control theory ,Electronic engineering ,business ,Continuous wavelet transform - Abstract
Analysis the common gear fault signal, using continuous wavelet transform well time-frequency characteristics and failure mechanism gear features, combined with quasi-periodic signal rotary mechanical characteristics of the continuous wavelet transform fault signal. This method can reduce the noise source and other incentives interference, remove the specific needs of the signal to improve signal stripping effect, the use of a certain type of gear failures this step, to get a clear diagnosis results show that this method has proven a strong application space.
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- 2014
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13. Precipitation of metastable phases and its effect on electrical resistivity of Al-0.96Mg2Si alloy during aging
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Xing-xing Liu, Jian Guo Tang, Zhen-xing Liu, Chen Qian, Ke Liu, Cui Lixin, and Xiao-Guang Zhao
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Microstructural evolution ,Materials science ,Precipitation (chemistry) ,Alloy ,Metallurgy ,Metals and Alloys ,engineering.material ,Geotechnical Engineering and Engineering Geology ,Condensed Matter Physics ,Transmission electron microscopy ,Electrical resistivity and conductivity ,Phase (matter) ,Metastability ,Materials Chemistry ,engineering ,Peak value ,Composite material - Abstract
The precipitation behavior and its influence on the electrical resistivity of the Al-0.96Mg2Si alloy during aging were investigated with in-situ resistivity measurement and transmission electron microscopy (TEM). The precipitates of the peak aged alloy include both β″ and β′, but the amount ratio of β″ to β′ varies with the aging temperature and time increasing. The precipitates during aging at 175 °C are dominated by needle-like β″ phases (including pre-β″ phase), the size of which increases with the time prolonging, but does not increase substantially after further aging. The evolution of electrical conductivity is directly related to such microstructural evolution. However, the hardness of the alloy stays at the peak value for a long term. When the alloy is aged at 195 °C, the ratio of β″ to β′ becomes the main factor to influence relative resistivity (Δρ) value. The higher the temperature is, the smaller the ratio is, and the faster the Δρ value decreases. Moreover, the hardness peak drops with the decrease of the ratio. With the size and distribution parameters measured from TEM images, a semi-quantitative relationship between precipitates and the electrical resistivity was established.
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- 2014
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14. Feature Analysis for Driller Trip Operation Using AC Variable Frequency Motor
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Xiao Li Yin, Zhen Xing Liu, and Cheng Zhou Fan
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Variable (computer science) ,Engineering ,Ac frequency ,Safe operation ,Control theory ,business.industry ,Feature (computer vision) ,Brake ,General Engineering ,Safety coefficient ,Winch ,business ,Automotive engineering - Abstract
This paper analyzed the kinematical and mechanical feature of the trip operation for the 03A driller based on the dynamic brake theory of AC variable frequency motor. The moving pattern of the strip operation and the variable information of the load in winch roller were mastered. We checked the safety coefficient of the winch brake and put forward the suggestions on the safe operation for AC variable frequency controlled driller. This paper is very important for promoting the application of AC frequency technology in drillers.
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- 2014
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15. Landau-type theorems for p-harmonic mappings or log-p-harmonic mappings
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Ming-Sheng Liu and Zhen-Xing Liu
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Pure mathematics ,Applied Mathematics ,Harmonic (mathematics) ,Type (model theory) ,Coincidence point ,Analysis ,Mathematics ,Harmonic mapping - Abstract
In this article, the Landau-type theorems of -harmonic mappings or log--harmonic mappings are provided. The results, presented in this article, improve the related results of Li and Wang, and Chen et al.
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- 2014
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16. Biodiesel Synthesis from Styrax Tonkinensis Catalyzed by S2O82-/ZrO2-TiO2-Fe3O4
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Xiao An Nie, Yi Gang Wang, and Zhen Xing Liu
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Biodiesel ,chemistry.chemical_compound ,Waste management ,Chemistry ,Yield (chemistry) ,General Medicine ,Transesterification ,Methanol ,Solid acid ,Catalysis ,Nuclear chemistry ,Styrax tonkinensis ,Autoclave - Abstract
The preparation of biodiesel from Styrax Tonkinensis catalyzed by solid acid S2O82-/ZrO2-TiO2-Fe3O4 at an autoclave was studied in this paper. The magnetic catalysts were characterized by XRD, which explained the high catalytic effect. At the same time, the recovery rate and usage count of catalysts were also studied. And the results showed that a high yield of transesterification can be obtained in a closed autoclave at the condition of catalyst amount 5 %, reaction time 1.5 h, reaction temperature 373K and methanol and oil molar ratio 10:1. The results also showed that the catalysts were still with a higher catalytic efficiency when the catalysts were calcinated after the forth usage.
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- 2014
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17. Characteristic of the Volatile Arsenic in Natural Gas and its Novel Determination Method
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Qi Tuan Yan, Da Zhen Tang, Sheng Wu, Rui Xu, Zhen Xing Liu, Shu-ying Wang, and Hao Xu
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inorganic chemicals ,integumentary system ,business.industry ,chemistry.chemical_element ,Sorption ,General Medicine ,Potassium persulfate ,Catalysis ,chemistry.chemical_compound ,Silver nitrate ,Total volatile ,chemistry ,Natural gas ,Nitric acid ,Environmental chemistry ,business ,Arsenic - Abstract
The occurrence of volatile arsenic in natural gas, could lead to the poisoning of catalyst in processing equipment, and pose a serious threat to human health. In order to detect the total volatile arsenic in natural gas, this paper analyzed the characteristic and original mechanism of the volatile arsenic first, then a novel method was carried out by using silver nitrate solution, saturated potassium persulfate solution and concentrated nitric acid solution as sorption solution, followed by volatile arsenic determination with ICP-MS .The result showed that 2% silver nitrate solution had a good adsorption effect to volatile arsenic, and the recoveries of arsenic ranged from 87%~103%, which basically met the demand for the rapid detection of volatile arsenic in natural gas.
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- 2014
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18. Experimental Study on Corrosion Prevention of a Multilayer Coating System
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Yu Feng Lu, Zhen Xing Liu, Huan Yang, Shi Qiu, and Fei Lu
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Materials science ,Metallurgy ,General Engineering ,engineering.material ,Corrosion ,Cathodic protection ,Metal ,Coating ,Coating system ,visual_art ,Immersion (virtual reality) ,visual_art.visual_art_medium ,engineering ,Nanometre ,Corrosion prevention - Abstract
Aiming to the corrosion prevention of 16MnR steel surface in the light aggregate concrete, the paper applies a kind of corrosion prevention system composed of layered coating. It utilizes measurement methods such as field emission scanning electron microscopy and energy disperse spectroscopy to study the corrosion and change process of this kind of coating system in the surface of 16MnR steel in the environment of light aggregate concrete and make the evaluation on its effect of corrosion protection. The experiment result indicates that due to its mechanical masking function, the layered coating system can effectively restrain immersion of the corrosive medium in early corrosion period so as to protect the metallic matrix. With the deepening of the corrosion, the nanometer Zn particle has the function of cathodic protection on the metallic matrix, effectively enhancing the comprehensive corrosion protection ability of the coating system.
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- 2014
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19. Landau-Type Theorems for Certain Biharmonic Mappings
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Ming-Sheng Liu, Zhen-Xing Liu, and Junfeng Xu
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Class (set theory) ,Article Subject ,Plane (geometry) ,lcsh:Mathematics ,Applied Mathematics ,Operator (physics) ,Mathematical analysis ,Of the form ,Harmonic (mathematics) ,Type (model theory) ,lcsh:QA1-939 ,Unit disk ,Biharmonic equation ,Analysis ,Mathematics - Abstract
LetF(z)=|z|2g(z)+h(z) (|z|<1)be a biharmonic mapping of the unit disk𝔻, wheregandhare harmonic in𝔻. In this paper, the Landau-type theorems for biharmonic mappings of the formL(F)are provided. HereLrepresents the linear complex operatorL=(z∂/∂z)-(z¯∂/∂z)¯defined on the class of complex-valuedC1functions in the plane. The results, presented in this paper, improve the related results of earlier authors.
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- 2014
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20. Biodiesel Preparation from Styrax Confusus Hemsl. Oil Catalyzed by Magnetic Catalyst S2O82--ZrO2/Fe3O4
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Yi Gang Wang, Xiao An Nie, and Zhen Xing Liu
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Biodiesel ,Materials science ,General Engineering ,Transesterification ,Raw material ,law.invention ,Catalysis ,chemistry.chemical_compound ,chemistry ,law ,Yield (chemistry) ,Organic chemistry ,Calcination ,Methanol ,BET theory ,Nuclear chemistry - Abstract
Styrax confusus Hemsl., a promising energy plant, was used as raw material for biodiesel preparation in this paper. The transesterification was catalyzed by magnetic catalyst S2O82--ZrO2/Fe3O4, prepared by chemical co-precipitation method. TEM images indicat that the average particle diameter of magnetic core Fe3O4 and catalyst carrier ZrO2/Fe3O4 are 5-20 nm and 30-50 nm respectively. Because of its unique porous structure the BET surface area could up to 140.75 m2/g. The results show that a best catalytic activity is obtained when the solid catalyst impregnated in 2.5 mol·L-1 (NH4)2S2O8, calcined at 400 °C for 3 h, and a high methyl ester yield could be obtained under the optimal reaction conditions of catalyst amount 4.5 % (wt/wt oil), molar ratio of methanol/oil 6:1, reaction temperature 65 °C and time 2.0 h.
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- 2013
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21. Relationship Between Differential Expression of Bax and Bcl-2 Genes and Developmental Differences of Porcine Parthenotes Cultured in PZM-3 and NCSU-23
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Mao-Sheng Cui, Guo-cai Han, Xianlong Wang, Jing Zhang, Zhen-Xing Liu, Shenming Zeng, and Yi Wu
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Zygote ,Cell ,Embryo ,Plant Science ,Biology ,Cleavage (embryo) ,In vitro maturation ,Andrology ,medicine.anatomical_structure ,Apoptosis ,embryonic structures ,Immunology ,medicine ,Blastocyst ,Agronomy and Crop Science ,Gene - Abstract
The developmental competence of porcine parthenotes cultured in porcine zygote medium-3 (PZM-3) and North Carolina State University-23 (NCSU-23) media was investigated. After in vitro maturation oocytes were electro-activated, and the subsequent developmental competence, rates of apoptotic, fragmented and arrested embryos from the two media were evaluated. Also, the ratio of mRNA expression of Bcl-2 and Bax gene was determined. Results demonstrated that cleavage, blastocyst, hatched blastocyst rates, and blastocyst cell numbers were significantly higher in PZM-3 than in NCSU-23. The rate of fragmented embryos in PZM-3 was lower than in NCSU-23 on d 1 and 3 ( P P P P P P
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- 2011
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22. Study of Electroless Plating Ni-B Composite Coating and its Properties
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Xiao Li Yin, Shi Qiu, Huan Yang, Yu Feng Lu, and Zhen Xing Liu
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Materials science ,Composite coating ,Coating ,Electroless plating ,Plating ,Metallurgy ,General Engineering ,engineering ,engineering.material ,Composite material ,Corrosion - Abstract
The properties of Ni-B composite coating and corrosion resistance on the surface of 45 steel were investigated in this paper. An optimal component of plating solution was determined by the measurements of the stability of different component of plating solution and coating hardness as well as corrosion rate under different heat treatment temperature. The experimental results indicated that, when the heat treatment temperature was 300°C, the coating hardness reached 257HV and the corrosion rate was less than 0.15g•m-1•h-1, therefore the coating possessed high corrosion resistance.
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- 2011
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23. An Optimization Method Selecting the Location Points for Drilling and Riveting of Aircraft’s Wing Panel
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Feng Gang Liu, Zhen Xing Liu, Kaifu Zhang, and Yuan Li
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Matching (statistics) ,Mathematical optimization ,Engineering ,Wing ,Linear programming ,business.industry ,Search algorithm ,Process (computing) ,Rivet ,Drilling ,General Medicine ,business ,Surface matching - Abstract
In order to select the optimal location points for automated drilling and riveting process, an optimization method selecting the location points of Aircraft’s Wing Panel in Automatic Drilling and Riveting System is presented. This method includes three steps: 1) building the matching model based on the multiplicity; 2) presenting the matching method based on scatter search algorithm; 3) selecting the optimal location points according to the minimal deviation based on linear programming method. This method was applied in a panel to match the mathematical surface and the fitting one of this panel perfectly and select the optimal location points. The efficacy and quality during the process of drilling and riveting of this panel was improved greatly.
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- 2011
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24. Relationships of Ca2+ Oscillations and ER Cluster Distribution to Porcine Oocyte Fragmentation
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Yang L, Xianlong Wang, Zhen-Xing Liu, Shenming Zeng, Shuan Zhao, Jing Zhang, Shen Liu, Da-Wei Tang, Yue Wu, Y. Wu, Mao-Sheng Cui, and Zhong-Jian Bao
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medicine.anatomical_structure ,General Veterinary ,Chemistry ,medicine ,Biophysics ,Cluster (physics) ,Animal Science and Zoology ,Ca2 oscillations ,Anatomy ,Fragmentation (cell biology) ,Oocyte - Published
- 2011
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25. The Influence of Dy3+ in the Novel Electron Trapping Materials (ETM) (ETM) SrS: Eu2+, Dy3+
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Zhen Xing Liu, Jia Yue Sun, and Hai Yan Du
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Materials science ,business.industry ,Mechanical Engineering ,Electron trapping ,Condensed Matter Physics ,Laser ,medicine.disease_cause ,law.invention ,Mechanics of Materials ,law ,Peak intensity ,Ultraviolet light ,medicine ,Optoelectronics ,General Materials Science ,Emission spectrum ,business ,Luminescence ,Ultraviolet ,Visible spectrum - Abstract
A new electron trapping materials (ETM) SrS: Eu2+, Dy3+, which was prepared by the method of high temperature solid-state reaction. The results indicate that both ultraviolet light and visible light can be used as exciting source to store energy. After exposed under ultraviolet, the sample was stimulated by 980nm laser. As a result, an obvious luminescence at 615 nm was detected. The up-conversion emission spectrum was found to be a continuous broadband spectrum resulted from the multi-transitions of Eu2+ 4f6→4f7 (8S7/2). The emission peak intensity of SrS: Eu2+, Dy3+ was stronger than SrS: Eu2+.
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- 2010
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26. Photostimulated Luminescence Studies of Electron Trapping Materials SrS:Eu2+,RE (RE= Dy3+,Yb3+,Pr3+,Ho3+,Tm3+)
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Hai Yan Du, Jia Yue Sun, and Zhen Xing Liu
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Materials science ,Photoluminescence ,Photostimulated luminescence ,Mechanical Engineering ,Electron trapping ,Condensed Matter Physics ,Laser ,Photochemistry ,PSL ,Fluorescence ,law.invention ,Ion ,Mechanics of Materials ,law ,General Materials Science ,Atomic physics ,Luminescence - Abstract
Trivalent rare-earth ions, Dy3+, Yb3+, Pr3+, Ho3+, Tm3+, have been investigated as the co-doped auxiliary sensitizer for the electron trapping materials SrS:Eu2+ in order to enhance the fluorescence properties. It is found that Dy3+ and Ho3+ has the optimum photoluminescence stimulated luminescence (PSL) effect among the selected trivalent rare-earth ions. All the SrS: Eu2+ samples coped by different trivalent rare-earth ions can be stimulated by 980 nm laser after exposing to the conventional sun light, and they emit PSL with the peak located at 615 nm. The present research also indicates that some co-doped rare earth ions can increase fluorescence intensities of the traditional electron trapping materials SrS: Eu2+.
- Published
- 2010
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27. Quasi-continuous reconnection accompanied by FTEs during IMF Bz≈0 nT observed by Double Star TC-1 at the dawnside magnetopause
- Author
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F. S. Mozer, Yulia Bogdanova, Zhen Xing Liu, Chris Carr, Tai Phan, Tao Chen, Henri Rème, Chao Shen, and Guang Qing Yan
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Atmospheric Science ,010504 meteorology & atmospheric sciences ,Aerospace Engineering ,Double star ,Astrophysics ,Atmospheric sciences ,01 natural sciences ,Flux Transfer Event ,Magnetosheath ,0103 physical sciences ,Interplanetary magnetic field ,010306 general physics ,0105 earth and related environmental sciences ,Physics ,Astronomy and Astrophysics ,continuous reconnection ,Magnetic field ,Boundary layer ,Geophysics ,flank magnetopause ,Space and Planetary Science ,Local time ,Physics::Space Physics ,General Earth and Planetary Sciences ,Flux transfer event ,Magnetopause - Abstract
During a one-hour interval of interplanetary magnetic field (IMF) B z ≈0nT, the equatorial spacecraft Double Star TC-1 encountered the dawn flank magnetopause many times at the magnetic local time (MLT) of about 08:00 and the latitude of about -27°. During each encounter, reconnection jets were observed with their velocities up to more than 500km/s, significantly higher than the background flow in the magnetosheath. The fast flows match the theoretical prediction of Alfvenic acceleration well. The medium temperature and density of ions in the boundary layer indicate the open magnetic field topology inside this layer. The mainly southward and tailward flows of the plasma jets alongside with the negative slopes of the Walen test indicate that the spacecraft was located south of the reconnection site, consistent with both anti-parallel and component reconnection models. The accelerated flows were observed lasting for about one hour, with some modulations by the oscillations of the magnetopause, but no reversals in the direction of V z were found during the interval. The significantly enhanced flows in the boundary layer compared to the adjacent magnetosheath indicate that the reconnection was quasi-continuously active at the magnetopause northward of the spacecraft under such IMF conditions. At the same time, the bipolar signatures in B N with enhancements of the magnetic field indicate the occurrence of the Flux Transfer Events (FTEs). The observed reconnection was quasi-continuous, whereas the simultaneously accompanied FTEs were time-dependent under the IMF B z ≈0nT. For this event, however, it is not possible to identify whether the reconnection was anti-parallel or component because the TC-1 was far away from the reconnection site. © 2015 COSPAR.
- Published
- 2015
28. Space Wind and Storms Exploration Program and International Living with a Star Initiative
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Jing‐Bin Cao and Zhen‐Xing Liu
- Subjects
Geomagnetic storm ,Physics ,Ionospheric storm ,Astrophysics::High Energy Astrophysical Phenomena ,General Medicine ,Geophysics ,Space weather ,Bow shocks in astrophysics ,Physics::Geophysics ,Solar wind ,Physics::Space Physics ,Coronal mass ejection ,Magnetopause ,Astrophysics::Earth and Planetary Astrophysics ,Thermosphere ,Physics::Atmospheric and Oceanic Physics - Abstract
The Space Wind and Storms Exploration Program (SWISE) is composed by three satellites in different orbits: (1) SWISE-1 in the ionosphere and thermosphere (300~700km) is designed to observe the response processes of ionospheric storm and thermospheric storm to solar activities and magnetospheric disturbances; (2) SWISE-2 in the near earth magnetosphere (700km~ 10RE) is designed to observe the response of magnetospheric space storms to solar activities and interplanetary disturbances; (3) SWISE-3 in the solar wind near bow shock is designed to observe the response of the solar wind near bow shock to solar activities and its influence to the geospace storms (including the magnetospheric substorm, magnetic storm, magnetospheric particle storms). These three satellites will form an exploration chain of solar-magnetosphere-ionosphere-thermosphere system. The SWISE mission is planned to be launched in 2010.
- Published
- 2005
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29. Transport of Ionospheric up-Flowing O+ION along the Field Line at Various Longitude to the Magnetosphere
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Zhen‐Xing Liu, Chun‐Qiang Li, and Jian‐Kui Shi
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Physics ,Field line ,Flux ,Magnetosphere ,General Medicine ,Geophysics ,Latitude ,Ion ,Computational physics ,Physics::Plasma Physics ,Physics::Space Physics ,Astrophysics::Earth and Planetary Astrophysics ,Ionosphere ,Longitude ,Ion transporter - Abstract
According to ion's distribution function found from the dynamic equation, the static flux distribution of the up-flowing O+ ion originating from various ionospheric regions along the field line at various longitude and the ion transport features are studied. The results show that: (1) The ions originating from the equatorial side of the dayside auroral zone and lower latitude region mainly transport into dayside magnetospheric region. The ions originating from the polar gap and polar side of the dayside auroral zone mainly transport into the magnetomantle and lob. The ions originating from equatorial side of the nightside auroral zone and lower latitude region mainly transport into the plasmasheet and the closed field line region. (2) The ionospheric up-flowing ions mainly distribute in near geo-space and ion's flux has a negative gradient versus geo-center distance. (3) If Kp is higher, the probability of the up-flowing ions to entry the magnetosphere will be bigger and the region where the up-flowing ions are dominant will be bigger. Our theoretical results can interpret some features of the geopause, and the theoretical flux of the ion in the magnetotail is consistent with the observation.
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- 2002
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30. Lysosomes are involved in induction of steroidogenic acute regulatory protein (StAR) gene expression and progesterone synthesis through low-density lipoprotein in cultured bovine granulosa cells
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Shuan Zhao, Yi Wu, Guixue Zhang, Zhen-Xing Liu, Shenming Zeng, and Jin-You Zhang
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endocrine system ,medicine.medical_specialty ,Granulosa cell ,Biology ,chemistry.chemical_compound ,Food Animals ,Internal medicine ,Gene expression ,Progesterone receptor ,medicine ,Animals ,Small Animals ,Cells, Cultured ,Progesterone ,Granulosa Cells ,urogenital system ,Equine ,Cholesterol ,Cholesterol side-chain cleavage enzyme ,Steroidogenic acute regulatory protein ,Phosphoproteins ,Lipoproteins, LDL ,Endocrinology ,chemistry ,Gene Expression Regulation ,Low-density lipoprotein ,lipids (amino acids, peptides, and proteins) ,Animal Science and Zoology ,Cattle ,Female ,Lysosomes ,Lipoprotein - Abstract
Progesterone is an important steroid hormone in the regulation of the bovine estrous cycle. The steroidogenic acute regulatory protein (StAR) is an indispensable component for transporting cholesterol to the inner mitochondrial membrane, which is one of the rate-limiting steps for progesterone synthesis. Low-density lipoprotein (LDL) supplies cholesterol precursors for progesterone formation, and the lysosomal degradation pathway of LDL is essential for progesterone biosynthesis in granulosa cells after ovulation. However, it is currently unknown how LDL and lysosomes coordinate the expression of the StAR gene and progesterone production in bovine granulosa cells. Here, we investigated the role of lysosomes in LDL-treated bovine granulosa cells. Our results reported that LDL induced expression of StAR messenger RNA and protein as well as expression of cholesterol side-chain cleavage cytochrome P-450 (CYP11A1) messenger RNA and progesterone production in cultured bovine granulosa cells. The number of lysosomes in the granulosa cells was also significantly increased by LDL; whereas the lysosomal inhibitor, chloroquine, strikingly abolished these LDL-induced effects. Our results indicate that LDL promotes StAR expression, synthesis of progesterone, and formation of lysosomes in bovine granulosa cells, and lysosomes participate in the process by releasing free cholesterol from hydrolyzed LDL.
- Published
- 2014
31. Age-associated potency decline in bovine oocytes is delayed by blocking extracellular Ca(2+) influx
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Shuan Zhao, Zhen-Xing Liu, Shenming Zeng, Yi Wu, Cui-Mei Wang, Kun Wang, Zhong-Jian Bao, and Guang-Min Yu
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medicine.medical_specialty ,Embryonic Development ,Biology ,Calcium in biology ,chemistry.chemical_compound ,Food Animals ,Internal medicine ,medicine ,Extracellular ,Animals ,Blastocyst ,Small Animals ,Egtazic Acid ,Cellular Senescence ,Equine ,Age Factors ,Glutathione ,1-Octanol ,Oocyte ,medicine.anatomical_structure ,Endocrinology ,chemistry ,Phorbol ,Oocytes ,Glutathione disulfide ,Tetradecanoylphorbol Acetate ,Animal Science and Zoology ,Calcium ,Cattle ,Cell aging - Abstract
Oocyte aging due to delayed fertilization is associated with declining quality and developmental potential. Intracellular calcium (Ca(2+)) concentration ([Ca(2+)]i) regulates oocyte growth, maturation, and fertilization and has also been implicated in aging. Using bovine oocytes, we tested the hypothesis that oocyte aging could be delayed by reducing [Ca(2+)]ivia blocking the influx of extracellular Ca(2+) or chelating ooplasmic free Ca(2+). After IVM, cumulus-oocyte complexes or denuded oocytes were cultured in medium supplemented with 1-octanol, phorbol 12-myristate 13-acetate, or 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis-acetoxymethyl ester (BAPTA-AM) to manipulate [Ca(2+)]i. Addition of 1-mM 1-octanol increased blastocyst development rates in the cumulus-oocyte complexes aged for 6 hours by IVF and for 6, 12, and 24 hours by parthenoactivation, and this effect was independent of the presence of cumulus cells. The intracellular levels of ATP, Glutathione, and Glutathione disulfide were not affected by 1-octanol, but [Ca(2+)]i was significantly decreased. When oocytes were cultured in Ca(2+)-free medium for 12 hours, the blastocyst development rate was greater and the beneficial effects of 1-octanol on oocyte aging were abolished. However, when the medium was supplemented with phorbol 12-myristate 13-acetate, [Ca(2+)]i increased and the blastocyst development rate decreased. Moreover, BAPTA-AM reduced [Ca(2+)]i and increased blastocyst development rates after IVF or parthenoactivation. We conclude that the age-associated developmental potency decline was delayed by blocking the influx of extracellular Ca(2+) or reducing ooplasmic free Ca(2+). 1-Octanol, BAPTA-AM, or Ca(2+)-free medium could be used to lengthen the fertilization windows of aged bovine oocytes.
- Published
- 2014
32. Imidazole inhibits autophagy flux by blocking autophagic degradation and triggers apoptosis via increasing FoxO3a-Bim expression
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Jingyou Zhang, Shuan Zhao, Yingzheng Wang, Yi Wu, Zhen-Xing Liu, and Shenming Zeng
- Subjects
Cancer Research ,Programmed cell death ,Apoptosis ,Vacuole ,Downregulation and upregulation ,Cell Line, Tumor ,Neoplasms ,Proto-Oncogene Proteins ,Autophagy ,Gene silencing ,Humans ,RNA, Small Interfering ,Caspase-9 ,biology ,Bcl-2-Like Protein 11 ,Caspase 3 ,Forkhead Box Protein O3 ,Imidazoles ,Membrane Proteins ,Forkhead Transcription Factors ,Cell cycle ,Caspase 9 ,Cell biology ,Gene Expression Regulation, Neoplastic ,Oncology ,biology.protein ,Apoptosis Regulatory Proteins - Abstract
Imidazole, an organic alkaloid, is an important pharmacophore in drug discovery. Anti-neoplastic potential of imidazole derivatives has been documented in several studies; however, mechanisms by which tumor cells respond to these stimuli remain to be elucidated. Autophagy and apoptosis have key roles in tumorigenesis and tumor treatment. In this study, we systematically examined autophagic events induced by imidazole in HEC-1B cells. Accumulation of autophagic vacuoles in imidazole-treated cells was verified by conversion of LC3 protein, as well as confocal and transmission electron microscopy. Furthermore, imidazole blocked autophagic degradation by impairing maturation of autophagosomes into autolysosomes. Concurrently, imidazole treatment induced apoptosis in HEC-1B cells, accompanied by activation of caspase 9 and 3. The proapoptotic effect was mediated by increased Bim expression. Moreover, imidazole upregulated the protein level of Foxo3a and induced its increased nuclear localisation. In addition, siRNA-mediated silencing of FoxO3a effectively attenuated imidazole-induced Bim upregulation and cell death, indicating direct involvement of this pathway in the imidazole-induced apoptosis. Taken together, our data provided a molecular link between imidazoles and anticancer therapies; understanding of these properties of imidazole is essential for development of effective cancer therapeutics using imidazoles.
- Published
- 2014
33. A novel role of transient receptor potential mucolipin1 (TRPML1) in protecting against imidazole-induced cytotoxicity
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Jingyou Zhang, Wu Shuaishuai, Shuan Zhao, Zhen-Xing Liu, Shenming Zeng, and Zunyang Nie
- Subjects
Programmed cell death ,Protein family ,Imidazoles ,Apoptosis ,Cell Biology ,Biology ,Hydrogen-Ion Concentration ,Biochemistry ,Cell biology ,Transient receptor potential channel ,chemistry.chemical_compound ,Transient Receptor Potential Channels ,chemistry ,Cell Line, Tumor ,Gene Knockdown Techniques ,Vacuoles ,Imidazole ,Humans ,Cytotoxicity ,Lysosomes ,Molecular Biology ,Cytoplasmic Vacuolation - Abstract
Lysosomotropic amines cause serious side effects such as cytoplasmic vacuolation and cell death. TRPML1 (also known as mucolipin1), a member of the transient receptor potential (TRP) protein family, may regulate fusion/fission of vesicles along the endocytic pathway and some aspects of lysosomal ion homeostasis. Nevertheless, it is still unknown whether TRPML1 is involved in death of mammalian cells induced by lysosomotropic agents. In this study, imidazole was used as a model to investigate the role of TRPML1 in the cytotoxicity of lysosomotropic agents. Overexpression of wild-type TRPML1 inhibited imidazole-induced vacuole formation and cell death in human endometrial adenocarcinoma (HEC-1B) cells. In contrast, siRNA-mediated TRPML1 knockdown increased the cell death induced by imidazole. Bafilomycin A1 raises the pH of acidic organelles and therefore suppresses accumulation of weak bases in them. Similarly, lysosomal pH was raised in TRPML1-overexpressing cells; therefore, we inferred that TRPML1 protected against imidazole toxicity by regulating the pH of acidic organelles. We concluded that TRPML1 had a novel role in protecting against lysosomotropic amine toxicity.
- Published
- 2014
34. The O+Ion Flux in the Martian Magnetosphere and Martian Intrinsic Moment
- Author
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Zhen-Xing Liu, Jian-Kui Shi, and T. L. Zchang
- Subjects
Martian ,Physics ,Spacecraft ,business.industry ,Magnetosphere ,Flux ,Astronomy and Astrophysics ,Astrophysics ,Ion ,Magnetic field ,Space and Planetary Science ,Physics::Space Physics ,Moment (physics) ,Astrophysics::Earth and Planetary Astrophysics ,Ionosphere ,business - Abstract
A model is developed to study the ionospheric ion flux distribution along magnetic force lines in Martian magnetosphere and the influence of Martian intrinsic moment on the distribution. It is discovered that the intrinsic moment has significant influence on the O + ion flux distribution that a lower flux in the magnetotail will be associated with a stronger intrinsic moment. According to the theoretical result and the observed data on the ion flux which is about 7.6×10 6 cm −2 s −1 in the Martian magnetotail, the deduced Martian moment is about 2×10 21 G cm 3 . This agrees well with the most recent data obtained by MAG/ER on the Mars Global Surveyor spacecraft.
- Published
- 2001
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35. Ion Acceleration in the Magnetotail During the Dipolarization: II Ion Acceleration and Energization
- Author
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Jian‐Kui Shi and Zhen‐Xing Liu
- Subjects
Physics ,Perpendicular direction ,Acceleration ,Physics::Plasma Physics ,Physics::Space Physics ,Substorm ,Ion distribution ,General Medicine ,Atomic physics ,Ion acceleration ,Dynamic equation ,Ion energy ,Ion - Abstract
According to the ion distribution functions for the up-flowing O+, H+, and He+ ions found by simulation with the dynamic equation in the dipolarization in the substorm, the ions acceleration and energization are investigated. The results show that, (1) the acceleration and energization mainly occur in the middle of the dipolarization and correspond to a distance of −12RE to −8RE, (2) the acceleration and energization along perpendicular direction are faster than that along parallel direction, (3) variations of velocity and energy for lighter ion are faster than that for heavier ion, (4) the higher the ion initial energy, the faster the ion acceleration will be, and the more energy is obtained by the ions. The ion energy calculated theoretically is as high as −102 keV at the end of the dipolarization in the magnetotail, this is consistent with the observation.
- Published
- 2000
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36. Transient Reconnection caused by the Impact and sudden Stop of Non-Homogeneous Dynamic Pressure
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Tao Chen and Zhen‐Xing Liu
- Subjects
Physics ,Magnetic reconnection ,General Medicine ,Mechanics ,External flow ,Vortex ,Boundary layer ,Current sheet ,Classical mechanics ,Physics::Plasma Physics ,Physics::Space Physics ,Astrophysics::Solar and Stellar Astrophysics ,Magnetopause ,Magnetohydrodynamics ,Shear flow - Abstract
It is proposed that local and transient reconnection in the plasma boundary layer can be caused by the impact and switch-off of non-homogenous dynamic pressure. The two dimensional compressible magnetohydrodynamic (MHD) simulation is used to investigate the reconnection processes in these two cases. It is found that the state of transverse flow and its lasting period play an important role in reconnection processes. When the transient flow is homogeneous, it does not causes reconnection, the magnetic field lines are only pushed downstream. When the transverse flow is sheared one, magnetic reconnection always occurs during the impacting period, and a new “reverse K” pattern reconnection configuration is formed in the current sheet region; after the external shear flow stop suddenly, the system of the plasma boundary layer becomes very unstable, many kinds of fluid vertex, flow pattern and reconnection configuration are generated in the current sheet region, the reconnection configurations are very different from that for impact phase. We suppose that the sudden stop of an external flow action may be an important trigger mechnism of energy conversion and magnetic reconnection. According to the simulation results. An alternative transient reconnection model has been proposed, it can be called “transient shear flow driven reconnection” model. This model is quite different from MXR model, VIR model and BSXR model. The reconnection mechanism proposed in this paper may be existed in some regions of space plasma, such as the subsolar point region of dayside magnetopause boundary layer. This reconnection model can be used to investigate the formation and structure of FTEs, osillation of magnetopause, vortex structure and the excitation of wave in the dayside magnetopause boundary layer.
- Published
- 2000
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37. Ion Accelleration in the Magnetotail during Magnetic Dipolarazation: I Temporal Variation of Ion Distribution Fuction
- Author
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Jian‐Kui Shi and Zhen‐Xing Liu
- Subjects
Physics ,Acceleration ,Distribution function ,Physics::Plasma Physics ,Electric field ,Phase space ,Substorm ,Magnetosphere ,General Medicine ,Ionosphere ,Atomic physics ,Ion - Abstract
Using dynamics equation, the temporal variation of ion distribution function during dipolarization of a substorm in the magneto-tail is simulated. The main results show that: (1) The ion distribution function which is initially exponentially decreasing with increasing speed becomes a single-peak distribution both in the parallel direction and in the perpendicular direction, and the peak moves towards higher speed with time. (2) In the phase space, the peak moves faster along V┴ direction than along V// direction. (3) The peak of lighter ion moves faster than that of heavier ion. (4) The higher the ion's initial energy, the faster the peak moves. (5) During the dipolarization, the ions move as an earthward flow. The acceleration of up-flowing ions by induced electric field is discussed.
- Published
- 2000
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- View/download PDF
38. A theoretical study on the O+ ions of the Martian magnetosphere
- Author
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T. L. Zhang, Zhen-xing Liu, and Jian-kui Shi
- Subjects
Physics ,Martian ,Field (physics) ,Astrophysics::High Energy Astrophysical Phenomena ,Magnetosphere ,Flux ,Astronomy and Astrophysics ,Computational physics ,Astrobiology ,L-shell ,Magnetic field ,Space and Planetary Science ,Physics::Space Physics ,Ionosphere ,Mercury's magnetic field - Abstract
A theoretical study is made on the O + density and flux profiles along magnetic field lines emanating from the Martian ionosphere, assuming that the Martian magnetic field consists of an intrinsic field and an induced field. Calculations are made for different values of the intrinsic field. It is found 1) that both the density and flux decrease with increasing areocentric distance, 2) that, as Z increases, both the density and flux decrease first, then slowly increase, 3) that the stronger the intrinsic magnetic field, the fast the density and flux fall with increasing areocentric distance, and 4) at a given distance in the magnetotail, the density and flux are the smaller, the greater the intrinsic magnetic field. Thus, by observing the density and flux distributions in the Martian magnetosphere one may learn about the size of the intrinsic field of the planet.
- Published
- 1999
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39. Evaluation of the possibility of utilization of poly(amidesulfonamide)s (PASAs) in ultrafiltration technology
- Author
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Suei Yee Lam-Leung, Zhen Xing Liu, and Wing Hong Chan
- Subjects
Chromatography ,Polymers and Plastics ,biology ,Chemistry ,Lithium bromide ,Ultrafiltration ,Serum albumin ,General Chemistry ,Casting ,Dimethylacetamide ,Surfaces, Coatings and Films ,chemistry.chemical_compound ,Membrane ,Materials Chemistry ,biology.protein ,Bovine serum albumin ,Phase inversion (chemistry) - Abstract
Ultrafiltration (UF) membranes of six selected poly(amidesulfonamide)s (PASAs) were prepared and studied. The pure water flux and the retention of albumin (bovine serum) were used to evaluate the quality of the UF performance of the fabricated membrane. Membranes with good mechanical strength were obtained by using the phase inversion method. A comparison of the UF performance of the PASA membranes fabricated from a casting solution containing 12% w/w PASAs and 4% w/w lithium bromide in dimethylacetamide was made. The best retention of albumin ( bovine serum) by membranes prepared under the conditions studied from the selected homopolymers of PASAs, and their corresponding pure water flux at 0.207 MPa, ranged from 84.6 to 100% and 120 to 396 L m -2 h -1 , respectively.
- Published
- 1998
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40. Identification and transcriptional profiling of differentially expressed genes associated with response to UVA radiation in Drosophila melanogaster (Diptera: Drosophilidae)
- Author
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Li-Jun Zhou, Nicolas Desneux, Chaoliang Lei, Zhi-Hui Zhu, Weihua Ma, Zhen-Xing Liu, Huazhong Agricultural University, Institut Sophia Agrobiotech (ISA), Centre National de la Recherche Scientifique (CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut National de la Recherche Agronomique (INRA), and National Natural Science Foundation of China [31171856]
- Subjects
0106 biological sciences ,INVOLVEMENT ,STRESS ,Ultraviolet Rays ,[SDV]Life Sciences [q-bio] ,INSECTS ,PROTEIN ,METABOLISM ,Real-Time Polymerase Chain Reaction ,01 natural sciences ,03 medical and health sciences ,real-time quantitative PCR ,Drosophilidae ,suppression subtractive hybridization ,Melanogaster ,Animals ,Gene ,Transcription factor ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,Gene Library ,Genetics ,Expressed Sequence Tags ,0303 health sciences ,Expressed sequence tag ,Ecology ,biology ,HELICOVERPA-ARMIGERA ADULTS ,Subtractive Hybridization Techniques ,cDNA library ,Gene Expression Profiling ,ultraviolet A radiation ,Sequence Analysis, DNA ,DEGRADATION ,biology.organism_classification ,EXCISION-REPAIR ,COLOR-VISION ,010602 entomology ,OXIDATIVE DNA-DAMAGE ,Drosophila melanogaster ,Gene Expression Regulation ,Suppression subtractive hybridization ,Insect Science ,transcription factor binding motif ,[SDE]Environmental Sciences ,sense organs - Abstract
International audience; UltravioletA (UVA) radiation, the major component of solar ultraviolet (UV) radiation reaching the earthOs surface, leads to negative effects in insects, such as oxidative stress, photoreceptor damage, and cell death. To better understand the molecular mechanisms of insect response to UVA radiation, suppression subtractive hybridization (SSH) and real-time quantitative polymerase chain reaction approaches were combined to reveal differential transcript expression in Drosophila melanogaster Meigen, 1830 (Diptera: Drosophilidae). In this study, two subtractive cDNA libraries were constructed and sequenced, obtaining 131 high-quality unique expressed sequence tags (ESTs) that were up-or downregulated in D. melanogaster exposed to UVA radiation for 0.5 h. Of the 131 ESTs, 102 unique ESTs were differentially expressed and classified into 10 functional categories. The results showed that UVA radiation induces expression of genes related to stress and defense response and metabolism. Potential transcription factor binding motifs upstream of these genes are associated with multiple signaling pathways that may help the insect cope with the stress of UVA radiation. To our knowledge, this is the first analysis of insect response toUVAradiation at the transcriptional level. Our results reveal that UVA radiation influences the expression profiles of stress-responsive genes and provide further insights into the mechanisms of adaptive response to UVA radiation stress.
- Published
- 2013
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41. The Disturbances of Endoplasmic Reticulum Calcium Homeostasis Caused by Increased Intracellular Reactive Oxygen Species Contributes to Fragmentation in Aged Porcine Oocytes1
- Author
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Yuan Fang, Yi Wu, Shuan Zhao, Guo-cai Han, Da-Wei Tang, Zhen-Xing Liu, Shenming Zeng, and Xianlong Wang
- Subjects
Calcium metabolism ,chemistry.chemical_classification ,Reactive oxygen species ,Endoplasmic reticulum ,chemistry.chemical_element ,Cell Biology ,General Medicine ,Cycloheximide ,Biology ,Calcium ,Cell biology ,chemistry.chemical_compound ,Reproductive Medicine ,chemistry ,Fragmentation (cell biology) ,Intracellular ,Homeostasis - Abstract
Accumulating evidence indicates that cellular and molecular abnormalities occur during oocyte aging, including fragmentation, increases in intracellular reactive oxygen species (ROS), and abnormal Ca(2+) oscillations. The objective of the present study was to characterize the relationships between intracellular ROS, Ca(2+) homeostasis of endoplasmic reticulum (ER), and fragmentation in aged porcine MII oocytes. Prolonged culture (36 h) of porcine oocytes resulted in elevated intracellular ROS level, impaired ER Ca(2+) homeostasis (i.e., Ca(2+) storage, Ca(2+) rising patterns after electroactivation, and the cluster distribution of ER), and increased fragmentation rates. However, when the porcine oocytes were treated with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl ester), an intracellular Ca(2+) chelator, the fragmentation was significantly inhibited during in vitro aging. In order to pursue the underlying mechanisms, H2O2 and cycloheximide (CHX) were used to artificially increase or inhibit, respectively, the intracellular ROS levels in aged porcine oocytes during in vitro culture. The results demonstrated that incubation of porcine MII oocytes with H2O2 damaged the ER clusters and the Ca(2+) regulation of ER, leading to a high proportion of fragmented oocytes. In contrast, CHX, an intracellular inhibitor of ROS generation, prevented both increase of ROS level and damage of the ER Ca(2+) homeostasis in porcine oocytes during aging, resulting in low fragmentation rate. We conclude that the increased intracellular ROS damaged the ER clusters and ER Ca(2+) homeostasis, resulting in a disorder in ooplasmic free Ca(2+), which caused the fragmentations seen in porcine MII oocytes during aging.
- Published
- 2013
- Full Text
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42. The disturbances of endoplasmic reticulum calcium homeostasis caused by increased intracellular reactive oxygen species contributes to fragmentation in aged porcine oocytes
- Author
-
Da-Wei, Tang, Yuan, Fang, Zhen-Xing, Liu, Yi, Wu, Xian-Long, Wang, Shuan, Zhao, Guo-Cai, Han, and Shen-Ming, Zeng
- Subjects
Swine ,Oocytes ,Animals ,Homeostasis ,Calcium ,Female ,DNA Fragmentation ,Endoplasmic Reticulum ,Reactive Oxygen Species ,Egtazic Acid ,Cells, Cultured ,Cellular Senescence ,Chelating Agents - Abstract
Accumulating evidence indicates that cellular and molecular abnormalities occur during oocyte aging, including fragmentation, increases in intracellular reactive oxygen species (ROS), and abnormal Ca(2+) oscillations. The objective of the present study was to characterize the relationships between intracellular ROS, Ca(2+) homeostasis of endoplasmic reticulum (ER), and fragmentation in aged porcine MII oocytes. Prolonged culture (36 h) of porcine oocytes resulted in elevated intracellular ROS level, impaired ER Ca(2+) homeostasis (i.e., Ca(2+) storage, Ca(2+) rising patterns after electroactivation, and the cluster distribution of ER), and increased fragmentation rates. However, when the porcine oocytes were treated with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl ester), an intracellular Ca(2+) chelator, the fragmentation was significantly inhibited during in vitro aging. In order to pursue the underlying mechanisms, H2O2 and cycloheximide (CHX) were used to artificially increase or inhibit, respectively, the intracellular ROS levels in aged porcine oocytes during in vitro culture. The results demonstrated that incubation of porcine MII oocytes with H2O2 damaged the ER clusters and the Ca(2+) regulation of ER, leading to a high proportion of fragmented oocytes. In contrast, CHX, an intracellular inhibitor of ROS generation, prevented both increase of ROS level and damage of the ER Ca(2+) homeostasis in porcine oocytes during aging, resulting in low fragmentation rate. We conclude that the increased intracellular ROS damaged the ER clusters and ER Ca(2+) homeostasis, resulting in a disorder in ooplasmic free Ca(2+), which caused the fragmentations seen in porcine MII oocytes during aging.
- Published
- 2013
43. Plasmonic silver nanosphere enhanced ZnSe nanoribbon/Si heterojunction optoelectronic devices
- Author
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Chunyan Wu, Li Wang, Lin-Bao Luo, Zhen-Xing Liu, Cai-Wang Ge, Shu-Juan He, Yongqiang Yu, Ran Chen, and Zhi-Fei Ren
- Subjects
Materials science ,Bioengineering ,Ag nanoparticles ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,law.invention ,Responsivity ,law ,Solar cell ,General Materials Science ,Electrical and Electronic Engineering ,Surface plasmon resonance ,Absorption (electromagnetic radiation) ,Plasmon ,Photocurrent ,business.industry ,Mechanical Engineering ,Heterojunction ,General Chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Mechanics of Materials ,Optoelectronics ,0210 nano-technology ,business - Abstract
In this study, we report a localized surface plasmon resonance (LSPR) enhanced optoelectronic device based on a ZnSe:Sb nanoribbon (NR)/Si nano-heterojunction. We experimentally demonstrated that the LSPR peaks of plasmonic Ag nanoparticles (Ag NPs) can be readily tuned by changing their size distribution. Optical analysis reveals that the absorption of ZnSe:Sb NRs was increased after the decoration of the Ag NPs with strong LSPR. Further analysis of the optoelectronic device confirmed the device performance can be promoted: for example, the short-circuit photocurrent density of the ZnSe/Si heterojunction solar cell was improved by 57.6% from 11.75 to 18.52 mA cm(-2) compared to that without Ag NPs. Meanwhile, the responsivity and detectivity of the ZnSe:Sb NRs/Si heterojunction device increased from 117.2 to 184.8 mA W(-1), and from 5.86 × 10(11) to 9.20 × 10(11) cm Hz(1/2) W(-1), respectively.
- Published
- 2016
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44. Prediction of Hidden Coal Gas Fire Spontaneous Combustion Source Based on Chaos Theory
- Author
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Xian-Min Ma and Zhen-Xing Liu
- Subjects
Engineering ,Petroleum engineering ,business.industry ,Fossil fuel ,Chaotic ,Coal gas ,Coal ,Sensitivity (control systems) ,business ,Combustion ,complex mixtures ,Spontaneous combustion ,Syngas - Abstract
Hidden coal gas fire spontaneous combustion troubles are one of the greatest threats to the coal safety production due to the gas explosion. In this paper, a novel method of prediction the hidden fire source is presented by means of choosing the concentration of CO gas as the indicator to detect the hidden coal gas fire location because CO gas is first reach the alarm threshold in the process of coal spontaneous combustion. The chaotic characteristics of CO gas are analyzed, and the duffing chaotic oscillator is used to detect the weak CO gas concentration signals, then the simulation model is established. The research experiment result shows that this method has high sensitivity for predicting the location of coal spontaneous combustion.
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- 2011
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45. Analysis of Unbalanced Black Ring Solutions within the Quasilocal Formalism
- Author
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Zhen-Xing Liu and Zeqian Chen
- Subjects
Physics ,High Energy Physics - Theory ,Statistical relation ,FOS: Physical sciences ,Astronomy and Astrophysics ,Conical surface ,Formalism (philosophy of mathematics) ,General Relativity and Quantum Cosmology ,Singularity ,High Energy Physics - Theory (hep-th) ,Space and Planetary Science ,Quantum ,Mathematical Physics ,First law of thermodynamics ,Mathematical physics - Abstract
We investigate the properties of rotating asymptotically flat black ring solutions in five-dimensional Einstein-Maxwell-dilaton gravity with the Kaluza-Klein coupling. Within the quasilocal formalism, the balance condition for these solutions is derived by using the conservation of the renormalized boundary stress-energy tensor, which is a new method proposed by Dumitru Astefanesei and his collaborators. We also study the thermodynamics of unbalanced black rings. The conserved charges and the thermodynamical quantities are computed. Due to the existence of a conical singularity in the boundary, these quantities differ from the original regular ones. It is shown that the Smarr relation and the quantum statistical relation are still satisfied. However, we get an extra term in the first law of thermodynamics. As the balance condition is imposed this extra term vanishes., Comment: 10 pages
- Published
- 2010
- Full Text
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46. Knowledge Application Techniques in Assistant Knowledge Base System for Product Design
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Zhen-xing Liu, Jianfeng Yu, Yuan Li, and Kaifu Zhang
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Knowledge management ,Knowledge representation and reasoning ,Product design ,Commonsense knowledge ,Computer science ,business.industry ,Knowledge engineering ,Open Knowledge Base Connectivity ,Mathematical knowledge management ,Body of knowledge ,Knowledge-based systems ,Knowledge base ,Knowledge extraction ,Knowledge integration ,Domain knowledge ,Software engineering ,business - Abstract
Product design which is one of the most important stages for manufacturing is a complex activity involving a great amount of knowledge. In this paper, knowledge is divided into three types: formula knowledge, diagram knowledge, table knowledge. Based on these requirements, knowledge base is constructed. This is used to store knowledge and to support the decision-making product design. First, the knowledge representation is formally described. Then, the knowledge navigation and search strategy is detailed. A specific section is dedicated to demonstrating the knowledge application techniques according to the different knowledge types that are proposed. The proposed methods are illustrated with examples. Finally, we conclude with the presentation of application performed with the knowledge application techniques.
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- 2009
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47. Fuzzy Neural Network Blind Equalization Algorithm Based on Radial Basis Function
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Ye-cai Guo, Yan-ping Zhang, Min Gao, Zhen-xing Liu, and Xue-qing Zhao
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Mean squared error ,Artificial neural network ,business.industry ,Fuzzy set ,MathematicsofComputing_NUMERICALANALYSIS ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Pattern recognition ,Fuzzy logic ,ComputingMethodologies_PATTERNRECOGNITION ,Computer Science::Computational Engineering, Finance, and Science ,Convergence (routing) ,Radial basis function ,Artificial intelligence ,Cluster analysis ,business ,Blind equalization ,Mathematics - Abstract
Radial Basis Function (RBF) networks have simple network structures and fast convergence speed. In this paper, we propose a fuzzy neural network blind equalization algorithm based on radial basis function (FNN-RBF-BLE). The proposed algorithm defines the centers of RBF equalizer by analyzing the relationship of the input signal of equalizer and transmitted signal, therefore the structures of equalizer become simpler and the convergence speed become faster. Then, we use the Fuzzy C-Means clustering algorithm (FCM) divide the input signal of equalizer into each cluster center with different membership values and the mean square error (MSE) is reduced. The performance of the proposed algorithm is compared with blind equalization algorithm based on RBF (RBF-BLE). It is shown that a relatively low mean square error and fast convergence speed has been achieved.
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- 2009
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- View/download PDF
48. Feed-Forward Neural Network Blind Equalization Algorithm Based on Super-Exponential Iterative
- Author
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Yan-ping Zhang, Min Gao, Zhen-xing Liu, and Ye-cai Guo
- Subjects
Rate of convergence ,Artificial neural network ,Mean squared error ,Computer science ,Iterative method ,Speech recognition ,Convergence (routing) ,Feedforward neural network ,Algorithm ,Underwater acoustic communication ,Blind equalization - Abstract
In order to overcome the slow convergence rate and larger mean square error of Feed-forward Neural Network(FNN) blind equalization algorithm, a feed-forward neural network blind equalization algorithm based on Super-Exponential Iterative(SEI) is proposed, on basis of the futures of Super-Exponential Iterative and feed-forward neural network blind equalization algorithm. The proposed algorithm has ability to improve convergence rate and to reduce mean square error via full using the whiten ability of SEI. With underwater acoustic channels simulation results show that the proposed algorithm has outperformed feed-forward neural network (FNN) blind equalization algorithm in the convergence rate and mean square error.
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- 2009
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49. Acceleration of Ionospheric Out-Flowing Ions in the Substorm in Geo-magnetotail
- Author
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Zhen-xing Liu Z X Liu, Jian-kui Shi J K Shi, T. L. Zhang, and Klaus Torkar
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Physics ,Acceleration ,Substorm ,General Physics and Astronomy ,Ion distribution ,Atomic physics ,Ion acceleration ,Ionosphere ,Ion energy ,Ion - Abstract
Using dynamics equation, acceleration of out-flowing ion during dipolarization in a substorm in the magnetotail is simulated. The main results show that: (1) The ion distribution function that is initially exponentially decreasing with increasing speed is turned into a single peak distribution, and with time the peak moves towards higher speed. (2) The peak moves along V⊥ faster than that along V||, and the ion acceleration mainly occurs in the middle of the dipolarization. (3) The higher the initial energy, the faster the peak moves, and the more energy is obtained by the ions. The ion energy theoretically calculated is as high as about 102 keV, this is consistent with the observation.
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- 1999
- Full Text
- View/download PDF
50. Solitary kinetic Alfvén waves with finite ion gyroradius
- Author
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Zhen-xing Liu, Zhong-yuan Li, Xu-yu Wang, and Xueyi Wang
- Subjects
Physics ,Gyroradius ,Condensed Matter Physics ,Kinetic energy ,Ion ,Computational physics ,Alfvén wave ,Amplitude ,Physics::Plasma Physics ,Physics::Space Physics ,Kinetic theory of gases ,Perpendicular ,Wavenumber ,Atomic physics - Abstract
A solitary kinetic Alfven wave (SKAW) with a finite ion gyroradius is obtained by using kinetic theory. It is found that the existence of SKAW depends not only on the parallel wave number but also on the perpendicular wave number. In contrast to the results with cold ions, both the super-Alfvenic and the sub-Alfvenic solitons exist in the density compressive region. The amplitude and the parallel propagation velocity of the solitons are found to be enhanced, while the width is narrowed due to the finite ion gyrodius effect.
- Published
- 1998
- Full Text
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