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Search Results: 1 - 10 of 27521 matches for " Hu Wenhua "
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Research on a New Control Strategy of Three Phase Inverter for Unbalanced Loads  [PDF]
Wenhua HU, Weiming Ma, Chunxi LIU
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2010, DOI: 10.4236/jemaa.2010.21006
Abstract: One of the very important functions of three-phase inverter is to maintain the symmetric three-phase output voltage when the three-phase loads are unbalanced. Although the traditional symmetrical component decomposing and superimpose theory can keep the voltage balance through compensating the positive-, negative- and zero-sequence components of the output voltage of inverter, however, this method is time-consuming and not suitable for control. Aiming at high power medium frequency inverter source, a P+Resonant (Proportion and Resonant) controller which ensured a balanced three phase output voltage under unbalanced load is proposed in this paper. The regulator was proved to be applicable to both three-phase three-wire system and three-phase four-wire system and developed two methods of realization. The simulation results verified that this method can suppressed effectively the output voltage distorted caused by the unbalanced load and attained a high quality voltage waveforms.
INTERNATIONAL STUDENTS’ ADJUSTMENT PROBLEMS AT UNIVERSITY: A CRITICAL LITERATURE REVIEW
Hu Wenhua,Zhang Zhe
Academic Research International , 2013,
Abstract: Adaptation to the new environment is critical for international students’ successful engagement with their learning at university. Identifying factors that influence their adaptation will be of great significance to help improve their adjustment. This paper critically reviews previous literature that investigated issues that hinder international undergraduate students’ adaptation at university. The literature search was carried out across four databases, i.e. Education Resources Information Centre (ERIC), British Education Index (BEI), Australian Education Index (AEI) and Scopus, by drawing on techniques adopted in both systematic literature review and naturalistic literature review. The problems identified in the literature are categorized into five groups: personal psychological issues, academic issues, socio-cultural issues, general living issues and English language proficiency, among which English language proficiency, financial problem, academic progress and homesickness seem to face most international students, though there has not been a consensus yet among researchers about the magnitude of these problems.
A New Type Power Converter and Its Application Prospect in Industry  [PDF]
Wenhua Hu, Pinggang Song, Zhongbin Chen, Qianzhi Zhou
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2011, DOI: 10.4236/jemaa.2011.33016
Abstract: A new type power convertsion mode is structured by combineing switch power conversion mode with linear amplifica-tion mode, so as to acquire their integrated optimal performances. The theoretical analyses and experimental results are presented in this paper. They are proved that the new type converter can match many kinds of loads, including nonlinear loads, with strong robustness, good waveforms and high efficiency. Its application prospect in industry can be expected, particularly for the conditions where serious static and dynamic performances are required.
Influence of Heavy Metals on Seed Germination and Early Seedling Growth in Crambe abyssinica, a Potential Industrial Oil Crop for Phytoremediation  [PDF]
Jin Hu, Zhaohui Deng, Bin Wang, Yuan Zhi, Bingxue Pei, Guangyu Zhang, Mingdan Luo, Banglian Huang, Wenhua Wu, Bangquan Huang
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.61017
Abstract: The influence of essential (Cu, Ni and Zn) and non-essential heavy metals (Hg, Cr, Pb and Cd) on seed germination and early seedling growth in industrial oil crop Crambe abyssinica was evaluated under laboratory conditions. Our results indicated that among the 7 heavy metals tested only Cu and Hg significantly (P < 0.01) decreased Crambe seed germination in a dose-dependent manner at higher concentrations while certain Cr concentrations significantly increased the seed germination (P < 0.05). All the 7 heavy metals decreased significantly relative root length, shoot length and fresh seedling weight in a dose-dependent manner (P < 0.01). The heavy metals except Ni decreased relative root length first, then shoot length or fresh seedling weight, and finally seed germination. Ni seemed to influence the relative fresh seedling weight first, then shoot length, root length and finally seed germination at lower concentrations, but the decrease in relative root length became faster when the Ni concentrations were increased. Our results indicated that Crambe is tolerant or moderately tolerant to the heavy metals tested except Ni and can be improved for phytoremediation of soils contaminated by heavy metals.
Determination of nuclear transcription factor activity using a modified electrophoretic mobility shift assay
Wang, Yong;Huang, Wenhua;Peng, Daizhi;Hu, Yuanbin;
Brazilian Archives of Biology and Technology , 2008, DOI: 10.1590/S1516-89132008000400025
Abstract: in this work, several major procedures of the electrophoretic mobility shift assay (emsa) were modified including swift extraction of the nucleic protein, labeling of the probe and radioautography. the modified assay required shorter time, simplified the nucleic protein extraction, increased the radioactivity of the labeling probe, skipped the tedious process of gel drying, and produced clear images. its results were comparable, reproducible and stable. it thus has merited for wide application.
Thesis Submission System of Structure Based on PHP
基于PHP构建学位论文提交系统

Chen Zhiqing Hu Wenhua,
陈枝清
,胡文华

现代图书情报技术 , 2002,
Abstract: PHP is a free server-side HTML embedded programming language.This article describes how to use PHP Access and Dreamweaver to develop thesis submission system.As a result,graduates can submit their thesises online.
Structural Characteristics and Genetic Mechanism of Fracture in Shiwu Oilfield
Hu Li,Qirong Qin,Wenhua Tang,Mingyuan Tang
Modern Applied Science , 2011, DOI: 10.5539/mas.v5n1p175
Abstract: Based on the core, chip,drilling, Seismic data,etc,Combining the tectonic evolution of shiwu fault, comprehensive study the Charcteristics of Structural, fracture and the genetic mechanism of fracture.after study:on the basis of the reaearch on the Xiaokuan fault and nearby north-south faults,6 secondary structure units are divided.They are: Xiaokuan extrusion and strike-slip zone,Qikeshu syncline belt,Dawujiazi and Xiaowujiazi fault belt,Nanling fault terrace,and Liangjiatun fault terrace.after study on the length and density by Weighting Process, Crack is developed in Shiwu Oilfield;it is affected by five tectonic movements and formed the four periods fracture;extensional directions of these fractures are NE,SN,NW,NNE,NNW,EW, etc.
Mining User Similarity Using Spatial-temporal Intersection
Yimin Wang,Ruimin Hu,Wenhua Huang,Jun Chen
International Journal of Computer Science Issues , 2013,
Abstract: The booming industry of location-based services has accumulated a huge collection of users location trajectories and also brings us opportunities and challenges to automatically discover valuable knowledge from these trajectories. In this paper, we investigate the problem of measuring the similarity between users. Such user similarity is significant to individuals, communities and businesses by helping them effectively retrieve the information. To achieve this goal, we firstly propose a storage structure to represent the users trajectories, which not only stores the sequence of users trajectory, but also stores regions with indexing of trajectories which pass the regions. After that, we give the similarity function between users using the spatio-temporal intersection in regions which are passed by the two users. Finally, we develop a spatio-temporal intersection algorithm to measure user similarity based on the definition and storage structure, and we illustrate the results and performance of the algorithm by extensive experiments.
Changes in Topological Organization of Functional PET Brain Network with Normal Aging
Zhiliang Liu, Lining Ke, Huafeng Liu, Wenhua Huang, Zhenghui Hu
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0088690
Abstract: Recent studies about brain network have suggested that normal aging is associated with alterations in coordinated patterns of the large-scale brain functional and structural systems. However, age-related changes in functional networks constructed via positron emission tomography (PET) data are still barely understood. Here, we constructed functional brain networks composed of regions in younger (mean age years) and older (mean age years) age groups with PET data. younger and older healthy individuals were separately selected for two age groups, from a physical examination database. Corresponding brain functional networks of the two groups were constructed by thresholding average cerebral glucose metabolism correlation matrices of regions and analysed using graph theoretical approaches. Although both groups showed normal small-world architecture in the PET networks, increased clustering and decreased efficiency were found in older subjects, implying a degeneration process that brain system shifts from a small-world network to regular one along with normal aging. Moreover, normal senescence was related to changed nodal centralities predominantly in association and paralimbic cortex regions, e.g. increasing in orbitofrontal cortex (middle) and decreasing in left hippocampus. Additionally, the older networks were about equally as robust to random failures as younger counterpart, but more vulnerable against targeted attacks. Finally, methods in the construction of the PET networks revealed reasonable robustness. Our findings enhanced the understanding about the topological principles of PET networks and changes related to normal aging.
Skeletal Muscle-Specific CPT1 Deficiency Elevates Lipotoxic Intermediates but Preserves Insulin Sensitivity
Wanchun Shi,Siping Hu,Wenhua Wang,Xiaohui Zhou,Wei Qiu
Journal of Diabetes Research , 2013, DOI: 10.1155/2013/163062
Abstract: Objective. By specific knockout of carnitine palmitoyl transferase 1b (CPT1b) in skeletal muscles, we explored the effect of CPT1b deficiency on lipids and insulin sensitivity. Methods. Mice with specific knockout of CPT1b in skeletal muscles (CPT1b M?/?) were used for the experiment group, with littermate C57BL/6 as controls (CPT1b). General and metabolic profiles were measured and compared between groups. mRNA expression and CPT1 activity were measured in skeletal muscle tissues and compared between groups. Mitochondrial fatty acid oxidation (FAO), triglycerides (TAGs), diglycerides (DAGs), and ceramides were examined in skeletal muscles in two groups. Phosphorylated AKT (pAkt) and glucose transporter 4 (Glut4) were determined with real-time polymerase chain reaction (RT-PCR). Insulin tolerance test, glucose tolerance test, and pyruvate oxidation were performed in both groups. Results. CPT1b M?/? model was successfully established, with impaired muscle CPT1 activity. Compared with CPT1b mice, CPT1b M?/? mice had similar food intake but lower body weight or fat mass and higher lipids but similar glucose or insulin levels. Their mitochondrial FAO of skeletal muscles was impaired. There were lipids accumulations (TAGs, DAGs, and ceramides) in skeletal muscle. However, pAkt and Glut4, insulin sensitivity, glucose tolerance, and pyruvate oxidation were preserved. Conclusion. Skeletal muscle-specific CPT1 deficiency elevates lipotoxic intermediates but preserves insulin sensitivity. 1. Introduction Obesity and diabetes have become such big worldwide health problems. The incidences were getting higher and higher [1]. Increased intramyocellular lipid accumulation plays a very important role in obesity and diabetes, as well as their complications [2, 3]. This attracted great interest in the effect of accumulated lipid intermediates on insulin resistance [4, 5]. Lipotoxicity was regarded as the link of high levels of lipids with impaired insulin signaling [6, 7]. This sparked the interest in how excessive lipid affects β-oxidation and mitochondrial biogenesis, which may have a great impact on glucose utilization and insulin resistance [7–10]. Carnitine palmitoyl transferase 1 (CPT1) is an important rate-limiting enzyme of mitochondrial β-oxidation, by controlling the mitochondrial uptake of long-chain acyl-CoAs. Its muscle isoform, CPT1b, is the predominant isoform rich in the heart and skeletal muscles [11]. It was suggested that inhibiting CPT1 activity by specific CPT1 inhibitors alleviates insulin resistance in diet-induced obese mice [12]. However,
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