28 results on '"You, Xiong"'
Search Results
2. Research on the Structure and Characteristics of the Overall Social Network of Professional Athletes
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Sai-Fu Fung, Yang Xun, Huanqing Wang, Yujiao Tan, Mingyou Gao, Shuqin Cui, Chenghao Wang, Yu Zhang, and You Xiong
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Article Subject ,General Computer Science ,Embeddedness ,Applied psychology ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,02 engineering and technology ,Power (social and political) ,Social support ,0502 economics and business ,0202 electrical engineering, electronic engineering, information engineering ,Relevance (information retrieval) ,Structure (mathematical logic) ,Multidisciplinary ,Social network ,biology ,business.industry ,Athletes ,05 social sciences ,020206 networking & telecommunications ,QA75.5-76.95 ,biology.organism_classification ,Electronic computers. Computer science ,Research Object ,Psychology ,business ,050203 business & management - Abstract
This study chooses Chinese athletes as the research object and constructs the overall network of its social support network and discussion network. From the micro-, meso-, and macrolevels of the social network structure, the structure and characteristics of the athlete’s overall social network are analyzed. Through research, we found that there is embeddedness, that is, the relevance, between society support networks, between society discussion networks, and between society support networks and society discussion networks. At the same time, in the athletes’ social support network and social discussion network, some athletes have no contact with other players; they have no “power” in the group as well, so it is difficult to obtain network resources. We also found that there are small-world characteristics in the social network of Chinese professional athletes. The above findings will provide a deeper understanding of the peculiarities of athlete groups and have certain practical significance for improving athletes’ daily training and life management conditions.
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- 2021
3. P‐92: A 12.3‐in. Top‐Emission AMOLED Transparent Display
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Qian Li, Haijun Qiu, Kezhi Liu, Jia Zeng, Zhengde Lai, Wenjie Hu, Shuang Zhao, Puyu Qi, Hui Zhao, Cuicui Liang, Hongting Lu, Yongqiang Du, Shanghong Li, Zhengmao Yu, Chen Wenbo, You-Xiong Feng, and Qiang Li
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AMOLED ,Materials science ,business.industry ,Optoelectronics ,Transparent display ,business - Published
- 2021
4. 11‐1: High Reliability Flexible AMOLED Display with Algorithm Compensation for Automotive Application
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Haijun Qiu, Xueying He, Wenjie Hu, Guowei Chen, Dawei Wang, Wenbao Gao, Lin Zhang, Gang Wang, Suncun Li, Yan Yang, Xing Huang, Lian Xiang, You-Xiong Feng, Zhengmao Yu, Xin Mou, Kai Yang, and Cuicui Liang
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Reliability (semiconductor) ,AMOLED ,business.industry ,Computer science ,OLED ,Automotive industry ,business ,Automotive engineering ,Compensation (engineering) - Published
- 2020
5. 14.4: Driving to the Future‐‐Flexible Active Matrix Organic Light Emitting Diode for Automotive Application
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Guo Wei Chen, Xin Mou, Hang Dong, and You Xiong Feng
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Materials science ,law ,business.industry ,OLED ,Automotive industry ,Optoelectronics ,business ,Active matrix ,law.invention - Published
- 2019
6. 52.4: Toward Longer Lifetime‐‐Elongating the Operation Lifetime of Organic Lighting Emitting Diode by Implementing Novel Driving Method
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Xing Huang, You-Xiong Feng, Wen-Bao Gao, Lin Zhang, Hai-Dong Wu, and Xin Mou
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Materials science ,business.industry ,OLED ,Optoelectronics ,business ,Diode - Published
- 2019
7. EVALUATION OF EFFECTIVENESS IN A NOVEL WOUND HEALING OINTMENT-CROCODILE OIL BURN OINTMENT
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Li-Wen Fu, Li-Ping Chen, Hua-Liang Li, Cao Xingmei, Zhang Ziran, Qi-Rui Fu, You-Xiong Xiong, Yi-Tao Deng, Ya-Hui Zheng, Jing Nie, Dong-Yan Shen, and Qing-Xi Chen
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0301 basic medicine ,Male ,Anti-Inflammatory Agents ,Drug Evaluation, Preclinical ,Crocodile oil burn ointment ,Ointments ,Mice ,0302 clinical medicine ,Edema ,Drug Discovery ,Medicine ,Skin ,Alligators and Crocodiles ,Analgesics ,integumentary system ,medicine.anatomical_structure ,Treatment Outcome ,030220 oncology & carcinogenesis ,Anesthesia ,Chinese herbal medicine ,medicine.symptom ,Burns ,medicine.drug ,medicine.medical_specialty ,Burn healing ,medicine.drug_class ,Rat model ,Analgesic ,Hair follicles ,Silver sulfadiazine ,Anti-inflammatory ,Article ,03 medical and health sciences ,Antinociceptive ,Animals ,Humans ,Rats, Wistar ,Wound Healing ,business.industry ,Hair follicle ,Dermatology ,Rats ,030104 developmental biology ,Complementary and alternative medicine ,Wound closure ,business ,Wound healing ,Oils - Abstract
Background: Crocodile oil and its products are used as ointments for burns and scalds in traditional medicines. A new ointment formulation - crocodile oil burn ointment (COBO) was developed to provide more efficient wound healing activity. The purpose of the study was to evaluate the burn healing efficacy of this new formulation by employing deep second-degree burns in a Wistar rat model. The analgesic and anti-inflammatory activities of COBO were also studied to provide some evidences for its further use. Materials and methods: The wound healing potential of this formulation was evaluated by employing a deep second-degree burn rat model and the efficiency was comparatively assessed against a reference ointment - (1% wt/wt) silver sulfadiazine (SSD). After 28 days, the animals were euthanized and the wounds were removed for transversal and longitudinal histological studies. Acetic acid-induced writhing in mice was used to evaluate the analgesic activity and its anti-inflammatory activity was observed in xylene -induced edema in mice. Results: COBO enhanced the burn wound healing (20.5±1.3 d) as indicated by significant decrease in wound closure time compared with the burn control (25.0±2.16 d) (P
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- 2016
8. A Practical Circuit Design for Measuring Output Voltage of High Voltage Frequency-modulated Power Supply
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You Xiong, Xiudong Wu, Yongkang Wang, Xingjun Lu, and Lei Yang
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Materials science ,business.industry ,Measuring output ,Circuit design ,Electrical engineering ,High voltage ,business ,Voltage ,Power (physics) - Published
- 2020
9. An untargeted metabolomics approach to investigate the wine-processed mechanism of Scutellariae radix in acute lung injury
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Ming Yang, Lingyun Zhong, Haojie Sun, Zhen-Feng Wu, Lianqi Hu, Ya-Qi Wang, and You Xiong
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Lipopolysaccharides ,Male ,Lipopolysaccharide ,Metabolite ,Acute Lung Injury ,Wine ,Lung injury ,Pharmacology ,Nitric Oxide ,Nitric oxide ,Proinflammatory cytokine ,Rats, Sprague-Dawley ,Biological pathway ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Metabolomics ,Drug Discovery ,Animals ,Medicine ,Lung ,030304 developmental biology ,0303 health sciences ,business.industry ,chemistry ,030220 oncology & carcinogenesis ,Cytokines ,Tumor necrosis factor alpha ,business ,Metabolic Networks and Pathways ,Scutellaria baicalensis - Abstract
Ethnopharmacological relevance Scutellariae radix (SR) is one of the most popular traditional Chinese medicines (TCM). Crude SR (CSR) and wine-processed SR (WSR) are the two most common commercial specifications. According to the theories of TCM, wine-processing increases the inclination and direction of SR’s actions, thereby strengthening its efficacy in clearing the upper-energizer lung damp heat. The pharmacological mechanism-related research on WSR for the treatment of lung disease is limited and needs to be expanded. Aim of the study The aim of this report was to identify the relevant biological pathways by assessing changes in plasma metabolites between CSR and WSR in a lipopolysaccharide (LPS)-induced acute lung injury (ALI) model, and thus, revealed the potential mechanism of wine processing in SR. Materials and methods Rats with LPS-induced ALI were treated with CSR and WSR. The contents of inflammatory cytokines and histopathological examination were determined to explore the effects of CSR and WSR. Next, the metabolic profiling of rat plasma samples was performed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). Then, principal component analysis (PCA) were used to provide an overview for all of the groups and orthogonal partial least squares-discriminant analysis (OPLS-DA) was utilized to maximize the discrimination and present the differences in the metabolite between all of the groups. Results WSR exhibited a more remarkable effect on improving ALI than CSR by reducing the levels of inflammatory factors, including nitric oxide (NO), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and interleukin-8 (IL-8). On the basis of UPLC-QTOF-MS technology, an unequal curative effect was revealed by nontargeting metabolomics. Sixteen biomarkers were discovered in the plasma of LPS-induced rats. Pathway analysis indicated that CSR acted on ALI by regulating the abnormal sphingolipid metabolism pathways; however, an WSR-mediated cure of ALI was linked primarily to reversing the abnormality of retinol metabolism pathways and tryptophan metabolism pathways. Conclusions This report examined the underlying wine-processing mechanism of SR from the perspective of plasma metabolites. In addition, this work provided a novel and valuable insight into interpretation of the processing mechanisms of TCM in a holistic way.
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- 2020
10. TFT-Directed Electroplating of RGB Luminescent Films without a Vacuum or Mask toward a Full-Color AMOLED Pixel Matrix
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Rong Wang, Wei-Jing Wu, Lei Zhou, Lei Wang, Yuguang Ma, Miao Xu, You Xiong, Donglian Zhang, Chen Weifeng, Yong Cao, Xuehong Zhou, Cao Liu, Linlin Liu, and Junbiao Peng
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Materials science ,Pixel ,business.industry ,Transistor ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,AMOLED ,Thin-film transistor ,law ,visual_art ,Electronic component ,visual_art.visual_art_medium ,Optoelectronics ,RGB color model ,General Materials Science ,Chromaticity ,0210 nano-technology ,business ,Diode - Abstract
The thin-film transistor (TFT) driving circuit is a separate electronic component embedded within the panel itself to switch the current for each pixel in active-matrix organic light-emitting diode displays. We reported a TFT-directed dye electroplating method to fabricate pixels; this would be a new method to deposit films on prepatterned electrode for organic full-color display, where TFT driving circuit provide a switching current signal to drive and direct dye depositing on selected RGB pixels. A prototype patterned color pixel matrix was achieved, as high-quality light-emitting films with uniform morphology, pure RGB chromaticity, and stable output.
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- 2018
11. The Fuzzy PID Control Simulation Research of the Macro-Micro Servo Driven Positioning Mechanism
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You Xiong Xu and Song Qing Zhu
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Engineering ,business.industry ,PID controller ,Control engineering ,General Medicine ,Fuzzy control system ,Software ,Machining ,Control theory ,Macro ,business ,MATLAB ,computer ,Servo ,Motion system ,computer.programming_language - Abstract
According to the contradiction between the large stroke and high precision of positioning mechanism, in order to solve the high precision positioning problem of large stroke motion system in precision machining and precision measurement fields, the macro-micro positioning mechanism based on electrohydraulic-piezoelectric hybrid servo was presented with the advantages of the electrohydraulic servo driven and the piezoelectric precision driven. Its combined simulation model based on AMESim and MATLAB/Simulink software was built. On this basis, its fuzzy PID control simulation research was done. The simulation results showed that compared with traditional PID, the positioning mechanism static and dynamic performance could be improved by using the fuzzy control method. This will provide control theoretical basis for practical engineering applications.
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- 2014
12. Development of a Condensation Refueling Gas Recovery System Based on Turbo Brayton Refrigeration Technique
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Lian You Xiong, Zhi Yong Huo, Wen Hai Lu, and Nan Peng
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Truck ,Engineering ,biology ,Waste management ,business.industry ,Turbo ,Condensation ,General Engineering ,Refrigerator car ,Refrigeration ,biology.organism_classification ,Brayton cycle ,Condensation temperature ,Gasoline ,business - Abstract
Volatile organic compounds (VOCs) are emitted from the refueling of gasoline vehicles and trucks. Controlling these emissions has been an important issue since the late 2000s in China. We have recently developed a condensation refueling gas recovery system to recover the VOCs from gaseous wastes at a bulk gasoline terminal. In this system VOC vapor is condensed by a reversed turbo-Brayton cycle refrigerator. The recovery system has a capacity of 100 Nm3/hr at the lowest condensation temperature of 190K. It has been put into use since 2008. The achieved recovery efficiency is 96% and the emission of VOCs is less than 8 g/m3 at the exit of the recovery system.
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- 2014
13. Dual Piezoelectric-Driving Pneumatic Digital Valve Control Method Simulation Research
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You Xiong Xu and Song Qing Zhu
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Engineering ,business.industry ,General Engineering ,PID controller ,Proportional control ,Piezoelectricity ,Dual (category theory) ,Control theory ,Overshoot (signal) ,State (computer science) ,MATLAB ,business ,computer ,Pulse-width modulation ,computer.programming_language - Abstract
Because its pilot stage is a two-position tree-way valve, the previously research piezoelectric type pneumatic digital valve also constantly works in on or off state even in the case of output stable pressure, which makes the valve with pressure fluctuation, waste gas and other shortcomings. In order to overcome the above problem, a novel pneumatic digital valve driven by dual piezoelectric is presented in this thesis. And its simulation model is built based on the AMESim and Matlab/simulink joint simulation platform. On this basis, its control method is researched by the simulation. The simulation shows that the Bang-Bang and the PWM control algorithm can basically achieve the digital proportional control of the valve, but the valve has overshoot. For this, the compound control algorithm with PID plus PWM is proposed to control the valve. The simulation results show that this algorithm is effective which can reduce the pressure overshoot.
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- 2013
14. Clinical and anatomical study of the distally based lesser saphenous veno-lateral sural neurocutaneous flap for lower extremity coverage
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Jing Xu, Zhu-You Xiong, Guangzao Li, Huijie Gu, and Chen Wang
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Adult ,Male ,medicine.medical_specialty ,Adolescent ,Sural nerve ,Surgical Flaps ,Young Adult ,Sural Nerve ,Humans ,Medicine ,Orthopedic Procedures ,Saphenous Vein ,Orthopedics and Sports Medicine ,Venous anatomy ,Aged ,Lesser saphenous vein ,business.industry ,Cutaneous nerve ,Soft tissue ,Sensory loss ,Anatomy ,Middle Aged ,Surgery ,Lower Extremity ,Orthopedic surgery ,Female ,Deep fascia ,business - Abstract
The distally based sural flap has been widely and successfully used to reconstruct soft tissue defects of the distal third of the lower leg and foot. Sensory loss and venous congestion are possible complications of this treatment, but there has been limited research focused on improving the sensory loss and veneous congestion. This study aimed to determine the spatial relationship between the lesser saphenous vein and the cutaneous nerves, the venous anatomy in the lower leg, and the nerve distribution in the lateral dorsum of the foot, and we presented our clinical experience.Twenty freshly amputated lower limbs were dissected in the 2 h following amputation. The lesser saphenous vein, medial/lateral sural nerve, and sural nerve were identified. Based on the anatomical studies, an island flap supplied by the vascular axis of the lesser saphenous vein and the lateral sural nerve was designed for clinical reparative applications in 24 cases.We indicated the spatial relationship between the lesser saphenous vein and the cutaneous nerves and the venous anatomy in the lower leg. Among 24 flaps, 21 showed complete survival (87.5%), while marginal flap necrosis occurred in two patients (8.33%) and distal wound dehiscence in another (4.17%). No symptomatic neuromas were observed. Their appearance and functioning were satisfactory, with filling maintained in the heel and lateral side of the foot.The distally based lesser saphenous veno-lateral sural neurocutaneous flap provides effective coverage of variable-sized soft tissue defects on the lower third of the lower leg and foot, without sensory loss and venous congestion.
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- 2013
15. Numerical Computation Studies and Hydrodynamic Analysis on the Cutting-Carrying and Lifting Capacity of Spiral Centralizer in Gas Drilling
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Hong Lin Xu, Zheng Mao Chen, and Ji You Xiong
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Engineering ,Finite volume method ,Blade (geometry) ,Turbulence ,business.industry ,Computation ,Drilling ,Mechanical engineering ,General Medicine ,Centralizer and normalizer ,Fluid dynamics ,business ,Astrophysics::Galaxy Astrophysics ,Spiral - Abstract
For gas drilling, hole cleaning is a particularly critical problem. When the spiral centralizer is used in the down hole assembly of gas drilling, it will produce a powerful rotational flow which will be bond to have the influence of different level on the hole cleaning. For this matter, this paper has established a three-dimensional fluid dynamics model in the basis of gas-solid two-phase turbulent theory and got its numerical solution by using the finite volume method, therefore making a quantitative evaluation about the ability of cutting-carrying and lifting of the spiral centralizer. The results have shown that the spiral centralizer has the function of cutting-carrying and lifting; part of the rock debris pellet concentrates in the bottom of the blade, above less instead. The numerical calculation method has some guiding significance for spiral centralizer design in gas drilling.
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- 2013
16. EDAHT: An Expertise Degree Analysis Model for Mass Comments in the E-Commerce System
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You Xiong, Guo Weili, Jiang Zhong, and Jingyi Xie
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Hierarchy ,Information retrieval ,Degree (graph theory) ,Computer science ,business.industry ,Feature extraction ,020206 networking & telecommunications ,02 engineering and technology ,E-commerce ,Construct (python library) ,Tree (data structure) ,Order (business) ,020204 information systems ,0202 electrical engineering, electronic engineering, information engineering ,Artificial intelligence ,business - Abstract
In order to help consumers to retrieve the most valuable information from amount of comments quickly, we present a method of evaluating the expertise degree of comments. Firstly, we propose an algorithm to construct automatically an attribute-word hierarchy tree from the massive comments data. Secondly, we develop an expertise degree analysis based on attribute-word hierarchy tree (EDAHT) to estimate the expertise degree of comments. The experiments results on 8,000 manual scoring data show that EDAHT model is high consistent with the manual scoring data, and this novel model is effective.
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- 2016
17. Crocodile Oil Enhances Cutaneous Burn Wound Healing and Reduces Scar Formation in Rats
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Li-Ping Chen, Yan Qin, Qing-Xi Chen, Hua-Liang Li, Ge Liang, Yong-Hua Hu, and You-Xiong Xiong
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medicine.medical_specialty ,Burn wound ,integumentary system ,biology ,business.industry ,medicine.medical_treatment ,Rat model ,General Medicine ,Crocodile ,Silver sulfadiazine ,medicine.disease ,biology.organism_classification ,Surgery ,Fibrosis ,biology.animal ,Anesthesia ,Crocodylus siamensis ,Emergency Medicine ,medicine ,Skin structure ,business ,Saline ,medicine.drug - Abstract
ACADEMIC EMERGENCY MEDICINE 2012; 19:265–273 © 2012 by the Society for Academic Emergency Medicine Abstract Objectives: This study was performed to evaluate the burn wound–healing efficacy of crocodile oil from Crocodylus siamensis by employing deep second-degree burns in a Wistar rat model. Methods: Twenty-four rats were assigned equally into four groups using a random-number table, and two burns were created on the dorsum of each animal except for the sham group. The three treatment groups received with saline solution (12 burns, served as negative control), silver sulfadiazine (12 burns, served as positive control), or crocodile oil (12 burns). Silver sulfadiazine cream was used as standard care, and the treatments were repeated twice daily for 28 days. After day 28 the animals were euthanized and the wounds were removed for quantitative real-time polymerase chain reaction, histologic, and immunohistochemical study. Results: Crocodile oil accelerated the wound-healing process as indicated by a significant decrease in wound closure time in comparison to the burn control and silver sulfadiazine treatment groups. Histologic results showed well-organized and distributed skin structure and collagen deposition in the animals treated with crocodile oil. Transforming growth factor-β1 (TGF-β1), a key cytokine promoting scarring, was also observed to play a role in the burn wound healing. Immunohistochemical staining results showed the negative expression of TGF-β1 and Smad3 in the 28-days-postburn skin of crocodile oil group versus positive in the epidermis of burn controls. Compared to the burn control group, expressions of TGF-β1 and Smad3 mRNA decreased significantly (p
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- 2012
18. Numerical Simulation of Two-Dimensional Turbulent in T-Tube Tee about Two Kinds of Angle
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Zhong Hua Tang and Mo You Xiong
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Engineering ,Computer simulation ,Field (physics) ,business.industry ,Internal flow ,Turbulence ,Flow (psychology) ,General Engineering ,Oblique case ,Mechanics ,Structural engineering ,Computational fluid dynamics ,Tube (container) ,business - Abstract
Due to T-tube tee is used mostly to connect ducts of the central air conditioning system, different angles of branch pipes caused different local resistance changes. This paper studied two-dimensional turbulent numerical simulation about inter flow of two kinds T-tube by numerical calculation software (CFD),in the method of implicit separation and standard k- ε two equations model, it is clear known that two kinds of forms tee fitting Angle of the internal flow field, Through the contrastive analysis of flow characteristics, it is obvious that local resistance of the oblique angled T-tube tee is much smaller than the common T-tube tee, and also is much more homogeneous.
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- 2010
19. Optimization of Piston Structure Aimed at Reducing Oil Consumption
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Pei You Xiong, Shi Ying Liu, Shu Feng Song, and Xu Dong Zhao
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Engineering ,Petroleum engineering ,business.industry ,General Engineering ,Oil consumption ,Diesel engine ,Automotive engineering ,Cylinder (engine) ,law.invention ,Piston ,law ,Ring oiler ,Oil pressure ,business ,Groove (engineering) - Abstract
Oil consumption of one certain diesel engine has been reduced by optimizing piston structure and piston kids clearance. The oil consumption principle inside the liner of engine was analyzed. Engine test was applied to validate the effect of the optimization. Due to the analysis, enlarge the pressure grads between piston top land and the 2nd land can push the 1st ring to the groove downside steadily. Adding or enlarging oil containing pocket above and below oil ring groove can reduce the oil pressure in these areas. Reasonable and large clearance between piston top land and cylinder liner help the gas burn completely.
- Published
- 2010
20. Morphological Characteristics of the Anterior Ethmoidal Artery in Ethmoid Roof and Endoscopic Localization
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Qin-kang Lu, Jianchun Liao, Rui-shan Dang, and You-xiong Yang
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Long axis ,Lamina ,business.industry ,Anatomy ,Dehiscence ,eye diseases ,Posterior ethmoid sinus ,medicine.anatomical_structure ,Anterior ethmoidal artery ,Cadaver ,medicine.artery ,otorhinolaryngologic diseases ,medicine ,Cribriform ,Original Article ,Neurology (clinical) ,business ,Orbit (anatomy) - Abstract
Objectives: To provide anatomical data to help identify and locate the anterior ethmoidal artery (AEA) precisely during endoscopic procedures. Method: We dissected 15 adult cadaver heads, which provided 30 specimens, to study morphological characteristics, courses, and several types of variations. Results: We found the average diameter of the AEA to be 0.80 ± 0.24 mm. In 85.7% of the cases, the artery was seen between the second and third lamella. Other locations were over the roof of the frontal recess cells (10.7%) and the roof of the posterior ethmoid sinus (3.6%). The AEA ran parallel to the ethmoid roof and formed a slight curve. When viewed from the superior side, the angle formed by the long axis of the artery and the lamina papyracea was 60.5 degrees ± 16.4 degrees. In 83.3% of the cases, the anterior ethmoidal canal (AEC) was identified as a separate canal, and in 16.7% the canal was embedded in the ethmoid roof. In 10 of the 30 cases (33.3%), the AEC presented some degree of dehiscence. Conclusion: As a result of these dissections, we found that the AEA's course in the ethmoid roof varies. The morphological characteristics—that the AEA runs parallel to the ethmoid roof, forming a slight posterolateral to anteromedial curve as it passes from the orbit to the cribriform plate—are the most reliable factors used to identify the artery during surgery.
- Published
- 2009
21. Characterization of electrostatically self-assembled nanocomposite thin films
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Kristie M. Lenahan, You-Xiong Wang, Aprillya Rosidian, Yanjing Liu, Tingying Zeng, and Richard O. Claus
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Auger electron spectroscopy ,Materials science ,Nanocomposite ,Absorption spectroscopy ,business.industry ,Nanotechnology ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,Characterization (materials science) ,Nanoclusters ,Optics ,Mechanics of Materials ,Ellipsometry ,Signal Processing ,General Materials Science ,Self-assembly ,Electrical and Electronic Engineering ,Thin film ,business ,Civil and Structural Engineering - Abstract
Multilayer thin films of metallic nanoclusters, polymers and other molecules have been formed using a novel electrostatic self-assembly method and analysed by multiple characterization techniques. Nanocluster size measurements, ellipsometry and UV-visible absorption spectroscopy have been used to confirm the linear build-up of the thin film thickness with the number of deposited nanocluster, polymer and other molecular layers. Auger electron spectroscopy allowed verification of the distribution of molecular species through thick films with multilayer segments containing different elements. Field emission scanning electron microscopy and atomic force microscopy permitted visualization of the morphologies of the outermost layers of the deposited films. Together, such characterization allows improved understanding and the basis for the design of multilayer thin film materials engineered to have specific molecular level structures and macroscopic functionalities.
- Published
- 1999
22. Nanostructured optical fiber sensors for breathing airflow monitoring
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Ignacio R. Matias, Yuhong Kang, Richard O. Claus, Jeffrey B. Mecham, Hang Ruan, You-Xiong Wang, and Francisco J. Arregui
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Optical fiber ,Materials science ,business.industry ,Instrumentation ,Thermistor ,Airflow ,engineering.material ,law.invention ,Optics ,Coating ,Fiber optic sensor ,law ,engineering ,Optoelectronics ,Thin film ,business ,Refractive index - Abstract
This paper presents recent progresses in the application of nanostructured optical fiber-based sensors for non-invasive, fast and reliable monitoring of respiratory airflow. Molecular-level self-assembly processing method is used to form multilayered inorganic nanocluster and polymer thin films on the distal ends of optical fibers to form such sensors. In order to optimize sensing performance, recent work has studies the synthesis process and the fundamental mechanisms for the change in optical reflection, specifically caused by exhaled air condensation on the coating surface. The physically small sensors fabricated by varying thin film chemistry, offer a full range of environmental relative humidity sensing from 0% to 100% with response times of microseconds, and mostly important, provide much higher sensitivity to breathing air, over 6 times larger than 100% relative humidity. The sensor performances in comparison with a medical nasal thermistor suggest such a thin film sensor an excellent device for advanced breathing airflow monitoring. All the features are appealing to clinical respiratory diagnosis and related sensor instrumentation design, and in good agreement with our analytical model.
- Published
- 2005
23. Nanometer-scale resonant cavities
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You-Xiong Wang, William B. Spillman, Fajian Zhang, Liangmin Zhang, and Richard O. Claus
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Optical fiber ,Materials science ,Geometrical optics ,business.industry ,Physics::Optics ,Resonance ,Laser ,Ray ,law.invention ,Longitudinal mode ,Resonator ,Optics ,law ,Optical cavity ,business - Abstract
Cavity enhanced directional resonance has been experimentally observed in single optically-trapped polystyrene particles, which have a size range from 9 μm down to several hundred nm. The higher resonance peaks correspond to longitudinal modes of the directional laser oscillation in a deformed spherical resonator. The lower peaks are attributed to whispering-gallery modes. For a particle with a diameter of approximately 9 μm, the longitudinal mode numbers of the resonator that is responsible for the observed sharp emission peaks are identified using a ray optics model. It is suggested that both directional and whispering-gallery modes can exist in nanometer-scale size resonators. The potential use of such resonant optical cavities in fiber-based optical sensors for chemical diagnostics is suggested. Considerable additional work is required to completely model and measure the observation of effects briefly summarized here.
- Published
- 2005
24. Optic fiber Fabry-Perot interferometer made through ionic self-assembly approach
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Haihu Yu, You-Xiong Wang, Desheng Jiang, Yanjing Liu, Ce-Wen Nan, and Richard O. Claus
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Optical fiber ,Materials science ,business.industry ,Polarization-maintaining optical fiber ,Graded-index fiber ,law.invention ,Optics ,law ,Fiber optic sensor ,Optoelectronics ,Fiber ,business ,Plastic optical fiber ,Hard-clad silica optical fiber ,Photonic-crystal fiber - Abstract
Polyelectrolyte multilayer thin films were coated onto flat glass substrates and optic fibers by using the ionic self-assembly technology. The deposition of the multilayers was monitored by using UV-vis spectroscopy, and the assembled thin films were characterized by small-angle X-ray reflectivity. Optic fiber polymer Fabry-Perot cavities were created by assembling polyelectrolytes onto the end faces of glass fibers, and the Fabry-Perot interference phenomena has been observed. It can be expected that novel fiber optical devices, such as Fabry-Perot filters, reflectors and Fabry-Perot cavity-based fiber optic sensors, can be developed via this approach.
- Published
- 2000
25. Electrostatic Self-Assembly of Multilayer Noncentrosymmetric Thin Films and Devices
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You-Xiong Wang, R.O. Claus, T. Zenga, W. Zhao, Yanjing Liu, and K. M. Lenahan
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chemistry.chemical_classification ,Materials science ,business.industry ,Polymer ,Piezoelectricity ,Polyelectrolyte ,Dipole ,chemistry ,Homogeneity (physics) ,Optoelectronics ,Molecule ,Self-assembly ,Thin film ,business - Abstract
The electrostatic self-assembly of multilayer thin films by alternate adsorption from polyelectrolyte solutions spontaneously leads to the formation of noncentrosymmetric structures if the molecules themselves have net dipole moments. Significant second-order nonlinear optical susceptibility has been observed in such films, using both commercially available chromophores and molecules specifically designed to yield an enhanced net dipole moment. Recent results indicate the capability to fabricate piezoelectric films using the same method. The nature of the deposition process results in an alignment of the chromophores that is stable over time and to temperatures up to 150°C, in contrast with poled polymers. ESA films offer the additional major advantages of excellent homogeneity and low optical loss, high thermal and chemical stability, and low cost.
- Published
- 1999
26. Ionically self-assembled second-order nonlinear optical thin film materials and devices
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Richard O. Claus, James R. Heflin, You-Xiong Wang, Kevin Lenehan, Yanjing Liu, and Wei Zhao
- Subjects
Dipole ,Materials science ,Optics ,business.industry ,Monolayer ,Second-harmonic generation ,Optoelectronics ,High harmonic generation ,Nonlinear optics ,Self-assembled monolayer ,Thin film ,business ,Polarization (waves) - Abstract
1Department ofElectrical Engineering, Virginia Tech, Blacksburg, VA 24061-03562Department of Physics, Virginia Tech, Blacksburg, VA 2406 1-0435AB STRACTWe report that a new ionically sell-assembled monolayer (ISAM) method for thin-filmdeposition can be employed to fabricate materials possessing the noncentrosymmetry that isrequired for a second order, x(2, nonlinear optical response. Using several differentcommercially-available polyelectrolytes and additional precursors designed and fabricated inour laboratories, we have produced ISAM nonlinear optical thin films with x(2 values greaterthan that of quartz. As a result of the ionic attraction between successive layers, the ISAM x(2films self-assemble into a noncentrosymmetric structure that has exhibited no measureabledecay of x(2 at room temperature over a period of more than four months. The x(2 of ISAMthin-films has been examined by second harmonic generation using a fundamental wavelengthof 1200 nm. The second harmonic intensity of the films exhibits the expected quadraticdependences of fundamental intensity and film thickness while the polarization dependence isconsistent with orientation of the chromophore dipole moment perpendicular to the substrate.We describe the potential application of such NLO thin-film materials in field sensing elementsand support instrumentation systems.Key words: ionicaily self-assembled monolayers, second harmonic generation, polar self-assembly, second order nonlinear optical susceptibifity, sensor devices
- Published
- 1998
27. Observation of whispering-gallery and directional resonant laser emission in ellipsoidal microcavities
- Author
-
Fajian Zhang, Liangmin Zhang, Richard O. Claus, and You-Xiong Wang
- Subjects
Physics ,business.industry ,Whispering gallery ,Mie scattering ,Physics::Optics ,Statistical and Nonlinear Physics ,Laser ,Optical microcavity ,Atomic and Molecular Physics, and Optics ,law.invention ,Optics ,law ,Excited state ,Emission spectrum ,Whispering-gallery wave ,Atomic physics ,Asymptotic expansion ,business - Abstract
Whispering-gallery resonant laser emission is reported in CdSe-tagged polystyrene microcavities. A clear intensity threshold for laser emission is observed. Using a recently developed asymptotic expansion derived from Mie theory, we have theoretically identified the experimentally observed discrete resonant peaks and assigned them to different quantum states. In fluorescent carboxylate-modified ellipsoidal polystyrene microcavities, we have observed that whispering-gallery mode and directional laser emission can be excited simultaneously. To understand our experimental results, we extend the asymptotic expansion from spherical to ellipsoidal microcavities to explain the whispering-gallery mode behavior and develop a simple ray-optics model to interpret the directional emission. The obtained numerical data agree well with experimental observation.
- Published
- 2006
28. Enhanced absorption and electro-optic Pockels effect of electrostatically self-assembled CdSe quantum dots
- Author
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Richard O. Claus, Fajian Zhang, You-Xiong Wang, and Liangmin Zhang
- Subjects
Materials science ,business.industry ,Materials Science (miscellaneous) ,Physics::Optics ,Industrial and Manufacturing Engineering ,Pockels effect ,symbols.namesake ,Optics ,Stark effect ,Nanocrystal ,Quantum dot ,Electro-absorption modulator ,symbols ,Optoelectronics ,Business and International Management ,Perturbation theory ,Thin film ,Photonics ,business - Abstract
The spectrum and electro-optic properties of CdSe quantum dots are studied. Spectrum wavelength shifts that are due to the quantum size effect and to the electro-optic Stark effect are investigated. It is found that CdSe quantum dot-polymer composites formed by an electrostatic self-assembly (ESA) technique exhibit high internal electric fields. Using the second-order perturbation theory of the 1s-1s energy shift (Stark effect), we estimate the internal field of the ESA film to be as high as 2.6 x 10(8) V/m. This value results in a much higher absorption coefficient and electro-optic coefficients for ESA films than for their bulk crystal counterparts or for spin-coated film samples. The relationships among unusual spectra, film structure, and high electro-optic response are analyzed. These results are useful both for understanding the physical mechanisms of semiconductor quantum dots and for developing high-performance photonic devices.
- Published
- 2005
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