检索结果-内蒙古大学图书馆

Investigate on the Reliability of Electronic Voltage Transformer Based on Capacitive Voltage Dividing with Low Capacity Under the Transient Impulse Voltage

Investigate on the Reliability of Electronic Voltage Transfo...

引用

The 5th International Conference on Reliability of Electrical Products and Electrical Contacts

作者： XiXiu Wu Ge Yan Yu Feng Benjin Wang Shipu Wu School of Automation Wuhan University of TechnologyWHUT China Electric Power Research Institute EPRI

Transfer overvoltage can be easily generated in the low voltage side of EVT（Electronic Voltage Transformer）based on capacitive voltage dividing under the transient impulse voltage of power *** overvoltage may damage the secondary equipment which connects with the voltage divider of EVT,resulting in the reliability of the whole EVT being reduced *** typical impulse voltages are chosen,which are standard lighting voltage and VFTO（Very Fast Transient Overvoltage caused by disconnect or operation）,to study the capacitance value of voltage divider influencing on the transient characteristic of the overvoltage at the low voltage side due to the transient impulse voltage *** amplitude value and the dominant frequency distribution of overvoltage in the low-voltage side are calculated with different main capacitance value（C=500pF and C=75pF）.Factors,such as the front time,the voltage rise rate and the voltage polarity of the transient voltage and the parameters of grounding network effecting on the low-voltage side overvoltage are analyzed as *** research results show that① As the value of the main capacitance C is smaller,the overvoltage generated at the low voltage side is lower.②The shorter front time and the faster voltage rise rate of transient impulse voltage lead to higher low-voltage side overvoltage;③The grounding network parameter inductance L has significant effect on the characteristics of low voltage side *** the value of L is larger,the overvoltage of low-voltage side is higher.④The value of the overvoltage caused by VFTO is always higher than that caused by the standard lighting voltage no matter how to change the parameters of grounding network under the condition of C=75pF;If C=500pF and L<10μH,low-voltage side overvoltage caused by VFTO is higher than that caused by standard lighting voltage,but when L>20μH,the result is inversed.

关键词： impulse voltage electronic voltage transformer capacitive voltage dividing reliability grounding network

来源：评论

学校读者我要写书评

暂无评论

Bimetallic PdCu nanoparticle decorated three-dimensional graphene hydrogel for non-enzymatic amperometric glucose sensor

引用

SENSORS AND ACTUATORS B-CHEMICAL 2014年 190卷 707-714页

作者： Yuan, Ming Liu, Aiping Zhao, Ming Dong, Wenjun Zhao, Tingyu Wang, Jiajun Tang, Weihua Zhejiang Sci Tech Univ Key Lab Adv Text Mat & Mfg Technol Minist Educ Ctr Optoelect Mat & Devices Hangzhou 310018 Zhejiang Peoples R China Zhejiang Univ Technol Minist Educ & Zhejiang Prov Key Lab E&M Hangzhou 310032 Zhejiang Peoples R China Beijing Univ Posts & Telecommun State Key Lab Informat Photon & Opt Commun Beijing 100876 Peoples R China

A bimetallic PdCu nanoparticle (NP) decorated three-dimensional graphene hydrogel (PdCu/ GE) was developed by a simple one-step hydrothermal method. The PdCu/GE hybrids exhibited an interconnected microporous framework with PdCu NPs dispersed and encapsulated within the GE layers. The PdCu/GE hybrids showed significant electrocatalytic activity toward glucose oxidation due to the synergistic effect of PdCu NPs and GE sheets in the alkaline solution containing chloride ions, presenting a substantial increase in the oxidation current and decrease in the onset potential of oxidation compared to the monometallic modified GE hybrids. At an applied potential of -0.4 V, the PdCu/ GE modified electrode with optimized bimetallic ratio presented quick respond to glucose oxidation with a wide linear range up to 18 mM and a reproducible sensitivity of 48 mu A (mg mM)(-1) in the presence of chloride ions. Furthermore, the PdCu/ GE modified electrode exhibited high selectivity to glucose and resistance against poisoning by commonly interfering species such as dopamine, ascorbic acid, uric acid, acetamidophenol and some monosaccharides. The PdCu/ GE hybrid hydrogels with 3D micropores were therefore promising for the future development of non-enzymatic amperometric glucose sensors with improved electrochemical performances. (c) 2013 Elsevier B. V. All rights reserved.

关键词： Graphene hydrogel Microporous structure Bimetallic nanoparticle Non-enzymatic glucose sensor

来源：评论

学校读者我要写书评

暂无评论

Self-consistent fluid modeling and simulation on a pulsed microwave atmospheric-pressure argon plasma jet

引用

JOURNAL OF APPLIED PHYSICS 2014年第15期116卷 153303-153303页

作者： Chen, Zhaoquan Yin, Zhixiang Chen, Minggong Hong, Lingli Xia, Guangqing Hu, Yelin Huang, Yourui Liu, Minghai Kudryavtsev, A. A. St Petersburg State Univ Fac Phys St Petersburg 198504 Russia Anhui Univ Sci & Technol Coll Elect & Informat Engn Huainan 232001 Anhui Peoples R China Huazhong Univ Sci & Technol State Key Lab Adv Electromagnet Engn & Technol Wuhan 430074 Hubei Peoples R China

In present study, a pulsed lower-power microwave-driven atmospheric-pressure argon plasma jet has been introduced with the type of coaxial transmission line resonator. The plasma jet plume is with room air temperature, even can be directly touched by human body without any hot harm. In order to study ionization process of the proposed plasma jet, a self-consistent hybrid fluid model is constructed in which Maxwell's equations are solved numerically by finite-difference time-domain method and a fluid model is used to study the characteristics of argon plasma evolution. With a Guass type input power function, the spatio-temporal distributions of the electron density, the electron temperature, the electric field, and the absorbed power density have been simulated, respectively. The simulation results suggest that the peak values of the electron temperature and the electric field are synchronous with the input pulsed microwave power but the maximum quantities of the electron density and the absorbed power density are lagged to the microwave power excitation. In addition, the pulsed plasma jet excited by the local enhanced electric field of surface plasmon polaritons should be the discharge mechanism of the proposed plasma jet. (C) 2014 AIP Publishing LLC.

关键词： Microwaves Electric fields Plasma temperature Microwave power transmission Pulsed power plasmas

来源：评论

学校读者我要写书评

暂无评论

Bayesian-Based Hybrid Simulation Approach to Project Completion Forecasting for Underground Construction

引用

JOURNAL OF CONSTRUCTION engineering AND MANAGEMENT 2014年第1期140卷

作者： Zhang, Sherong Du, Chengbo Sa, Wenqi Wang, Chao Wang, Gaohui Tianjin Univ State Key Lab Hydraul Engn Simulat & Safety Tianjin 300072 Peoples R China

Real-time simulation is powerful in forecasting the completion probability of long-term projects with repetitive tasks but fails to consider the time-varying uncertainty of inputs caused by construction process variabilities. In this paper, an improved method is introduced for predicting the time-varying probability of project completion of ongoing underground cavern group projects using Bayesian updating techniques. Within a tailor-made hierarchical simulation model, the Bayesian approach is adopted to constantly update duration distributions of unfinished project activities according to onsite data. The probability of project completion can therefore be increasingly refined during the process. The methodology is further explained in a case study where its feasibility and advantage over traditional approaches are verified. The success may also be replicated in addressing other similar time-varying uncertainty issues inherently present in almost all construction projects.

关键词： Forecasting Simulation Bayesian analysis Underground construction Excavation Hybrid methods Forecasting Simulation Bayesian analysis Underground construction Excavation Cost and schedule

来源：评论

学校读者我要写书评

暂无评论

Integrin αvβ3 mediates the synergetic regulation of core-binding factor α1 transcriptional activity by gravity and insulin-like growth factor-1 through phosphoinositide 3-kinase signaling

引用

BONE 2014年 69卷 126-132页

作者： Dai, Zhongquan Guo, Feima Wu, Feng Xu, Hongjie Yang, Chao Li, Jinqiao Liang, Peilong Zhang, Hongyu Qu, Lina Tan, Yingjun Wan, Yumin Li, Yinghui China Astronaut Res & Training Ctr State Key Lab Space Med Fundamentals & Applicat Beijing 100094 Peoples R China

Mechanical stimulation and biological factors coordinately regulate bone development and regeneration;however, the underlying mechanisms are poorly understood. Microgravity induces bone loss, which may be partly related to the development of resistance to local cytokines, including insulin-like growth factor 1 (IGF-1). Here, we report the involvement of integrin alpha v beta 3 in microgravity-associated bone loss. An established OSE-3T3 cell model was stably transfected with a 60SE2 (Osteoblast-Specific Element 2)-luciferase reporter and cultured under simulated microgravity (SMG) and hypergravity (HG) conditions in the presence or absence of IGF-1, the disintegrin echistatin, the phosphoinositide 3-kinase (PI3K) inhibitor LY294002, or combinations of these agents. Activity of core-binding factor alpha 1 (Cbfa1), an essential transcription factor for osteoblastic differentiation and osteogenesis, was reflected by luciferase activity. Different gravity conditions affected the induction of IGF-1 and subsequent effects on Cbfa1 transcription activity. SMG and HG influenced the expression and activity of integrin alpha v beta 3 and phosphorylation level of p85. LY294002 inhibited the effects of HG or IGF-1 on Cbfa1 activity, indicating that HG and IGF-1 could increase Cbfa1 activity via PI3K signaling. Inhibition of integrin alpha v beta 3 by echistatin attenuated the induction of IGF-1 and thus its effect on Cbfa1 activity under normal and HG conditions. Co-immunoprecipitation demonstrated that integrin beta 3 interacted with insulin receptor substrate 1, and that this interaction was decreased under SMG and increased under HG conditions. These results suggest that integrin alpha v beta 3 mediates the synergetic regulation of Cbfa1 transcription activity by gravity and IGF-1 via PI3K signaling. (C) 2014 Elsevier Inc. All rights reserved.

关键词： Bone loss Cbfa1 Gravity IGF-1 Integrin alpha v beta 3 Synergetic regulation

来源：评论

学校读者我要写书评

暂无评论

Nanoscale SnO2 Flat-Type Coplanar Hexanal Gas Sensor Arrays at ppb Level

引用

JOURNAL OF NANOSCIENCE AND NANOtechnology 2013年第6期13卷 4370-4374页

作者： Huang, Kaijin Zhu, Chao Yuan, Fangli Xie, Changsheng Huazhong Univ Sci & Technol State Key Lab Mat Proc & & Mould Technol Wuhan 430074 Peoples R China Chinese Acad Sci Inst Proc Engn State Key Lab Multiphase Complex Syst Beijing 100190 Peoples R China Wuhan Univ Technol State Key Lab Adv Technol Mat Synth & Proc Wuhan 430070 Peoples R China

Hexanal is one of the most important aroma compounds which play a crucial role in the odor of cereal, meat, fruit, plant oils and wood. The detection technique of hexanal has attracted more attention. In this paper, the nano-SnO2 flat-type coplanar hexanal gas sensor arrays were fabricated by screen-printing technique based on nano-SnO2 powders prepared by hydrothermal method. The test results show that the nano-SnO2 flat-type coplanar gas sensor arrays have good hexanal gas-sensing characteristics, such as low detection limit and high sensitivity. Especially, the gas sensitivity of the nano-SnO2 gas sensor arrays to 100 ppb hexanal can reach 2.8 at 350 degrees C. The nanometer size effect of nano-SnO2 and nature property of hexanal caused the ppb-level hexanal gas sensing characteristics.

关键词： Nano-SnO2 Hydrothermal Method Screen-Printing Technique Hexanal Gas-Sensing Property ppb Level

来源：评论

学校读者我要写书评

暂无评论

Fabrication and Hexanal Gas Sensing Property of Nano-SnO2 Flat-type Coplanar Gas Sensor Arrays at Ppb Level

引用

CURRENT NANOSCIENCE 2013年第3期9卷 357-362页

作者： Huang, Kaijin Zhang, Zhenxin Yuan, Fangli Xie, Changsheng Huazhong Univ Sci & Technol State Key Lab Mat Proc & Die & Mould Technol Wuhan 430074 Hubei Peoples R China Chinese Acad Sci Inst Proc Engn State Key Lab Multiphase Complex Syst Beijing 100190 Peoples R China Wuhan Univ Technol State Key Lab Adv Technol Mat Synth & Proc Wuhan 430070 Peoples R China

The detection of hexanal has attracted much attention because hexanal has an important effect on food quality and human health. In this paper, nano-SnO2 flat-type coplanar hexanal gas sensor arrays at the ppb level were fabricated by a screen-printing technique based on nano-SnO2 powders prepared by a sol-gel method. The test results show that the nano-SnO2 flat-type coplanar gas sensor arrays have good hexanal gas-sensing characteristics such as short response time, low detection limit, high sensitivity. Especially, the gas sensitivity of the nano-SnO2 gas sensor arrays to 50 ppb hexanal reached 9.5 at a working temperature of 200 degrees C. Nanometer-size effects, lattice distortion of nano-SnO2, and the natural properties of hexanal caused the ppb-level hexanal gas-sensing characteristics.

关键词： Flat-type coplanar gas sensor arrays gas-sensing property hexanal nano-SnO2 ppb level

来源：评论

学校读者我要写书评

暂无评论

In situ diffuse reflectance infrared Fourier transform spectroscopy study of formaldehyde adsorption and reactions on nano γ-Fe2O3 films

引用

APPLIED SURFACE SCIENCE 2013年 270卷 405-410页

作者： Huang, Kaijin Kong, Lingcong Yuan, Fangli Xie, Changsheng Huazhong Univ Sci & Technol State Key Lab Mat Proc & Die & Mould Technol Wuhan 430074 Peoples R China Chinese Acad Sci Inst Proc Engn State Key Lab Multiphase Complex Syst Beijing 100190 Peoples R China Wuhan Univ Technol State Key Lab Adv Technol Mat Synth & Proc Wuhan 430070 Peoples R China

The nano gamma-Fe2O3 films gas sensor was fabricated by the screen printing technology. The phase structures and morphologies of nano gamma-Fe2O3 films were characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM), respectively. The gas sensitivity of the films to 100 ppm formaldehyde was investigated. The surface adsorption and reaction process between nano gamma-Fe2O3 films and formaldehyde was studied by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) method at different temperatures. DRIFTS results showed that dioxymethylene, formate ions, polyoxymethylene and molecularly formaldehyde surface species were detected when the nano gamma-Fe2O3 films exposed to 100 ppm formaldehyde at different temperatures. A possible mechanism of the reaction process was discussed. (c) 2013 Elsevier B.V. All rights reserved.

关键词： Gas sensors Nano gamma-Fe2O3 films Formaldehyde DRIFTS Gas sensing mechanism

来源：评论

学校读者我要写书评

暂无评论

NUMERICAL SIMULATION OF TEMPERATURE FIELD OF PLASMA ARC REMELTING ON EN-SGJ-600-3

引用

engineering REVIEW 2013年第2期33卷 115-121页

作者： Lu, J. Sun, B. Tang, F. Ding, T. Zhang, L. Zhongyuan Univ Technol Sch Mat & Chem Engn Zhengzhou 450007 Henan Peoples R China Zhengzhou Res Inst Mech Engn State Key Lab Adv Brazing Filler Met & Technol Zhengzhou 450007 Henan Peoples R China

Plasma arc remelting treatment has been conducted on EN-SGJ-600-3. The microstructure of the melted zone and heat affected zone has been analyzed using an optical microscope. Then in view of the thermal physical parameters of material, latent heat and travelling heat sources, three-D FEA model of the transient temperature field during plasma arc remelting of the surface layer in EN-SGJ-600-3 has been established based on ANSYS software. The APDL (ANSYS Parametric Design Language) has been used to describe the evolvement rules of the temperature field. The results show that the microstructure in the remelted zone is pearlite and ledeburite, whose microhardness reaches 1000 similar to 1060 HV. It is worth pointing out that the simulation results of remelted shape are in accordance with the experimental results. The temperature near the surface of the weld pool is the highest, which is up to 1794 degrees C. This investigation will provide a guide for evaluating the validity of simulation studies.

关键词： Plasma arc remelting Temperature field Ansys EN-SGJ-600-3

来源：评论

学校读者我要写书评

暂无评论

Highly enantioselective oxidation of racemic phenyl-1,2-ethanediol to optically pure (R)-(-)-mandelic acid by a newly isolated Brevibacterium lutescens CCZU12-1

引用

APPLIED MICROBIOLOGY AND BIOtechnology 2013年第16期97卷 7185-7194页

作者： He, Yu-Cai Ma, Cui-Luan Zhang, Xian Li, Liang Xu, Jian-He Wu, Miao-Xin Changzhou Univ Coll Pharmaceut & Life Sci Biochem Engn Lab Changzhou 213164 Peoples R China Jiangsu Key Lab Adv Catalyt Mat & Technol Changzhou 213164 Peoples R China E China Univ Sci & Technol State Key Lab Bioreactor Engn Shanghai 200237 Peoples R China

Enantioselective oxidation of racemic phenyl-1,2-ethanediol into (R)-(-)-mandelic acid by a newly isolated Brevibacterium lutescens CCZU12-1 was demonstrated. It was found that optically active (R)-(-)-mandelic acid (e.e.p > 99.9 %) is produced leaving the other enantiomer (S)-(+)-phenyl-1,2-ethanediol intact. Using fed-batch method, a total of 172.9 mM (R)-(-)-mandelic acid accumulated in the reaction mixture after the seventh feed. Moreover, oxidation of phenyl-1,2-ethanediol using calcium alginate-entrapped resting cells was carried out in the aqueous system, and efficient biocatalyst recycling was achieved as a result of cell immobilization in calcium alginate, with a product-to-biocatalyst ratio of 27.94 g (R)-(-)-mandelic acid g(-1) dry cell weight cell after 16 cycles of repeated use.

关键词： (R)-(-)-Mandelic acid Phenyl-1,2-ethanediol Brevibacterium lutescens CCZU12-1 Biotransformation Enantioselective oxidation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：