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Search Results: 1 - 10 of 50993 matches for " Tengfei Wei "
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A Novel Over-Current Protection Technique Applied to Peak-Current Type DC-DC Converter  [PDF]
Yu Fang, Tengfei Wei, Liang He, Yong Xie, Yan Xing
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2010, DOI: 10.4236/jemaa.2010.26045
Abstract: The change of the over-current protection point of the power switches, caused by slope compensation, is analyzed in detail. It is discovered that the peak current protecting value increases as the duty cycle decreases. As a result, the safety operation of the switches is damaged greatly. A novel solution to improve over-current protection with constant peak current limitation is proposed by inducing synchronous slope compensation into the current limit function instead of the original constant voltage. The design principle and method of the protection circuit based on a UC3846 PWM controller for the interleaved dual-forward converter is presented. Experimental results are given to verify the analysis.
A Review of the Impact of Traditional Culture on Auditing  [PDF]
Tengfei Wu
American Journal of Industrial and Business Management (AJIBM) , 2019, DOI: 10.4236/ajibm.2019.93051
This paper reviews the main literature on cultural research and auditing research at home and abroad, and provides a theoretical basis for the study of the impact of traditional culture on auditing. The following chapters of this paper are divided into the following sections: the first section introduces the research literature on auditing, the second section introduces the literature on cultural development level, the third section introduces the impact of culture on business and individual behavior, the fourth section introduces the literature on the impact of culture on accounting and auditing, Section 5 is the research literature on the impact of Chinese traditional culture on corporate behavior, and Section 6 is a summary and review of domestic and foreign literature.
Jumps in High-Frequency Data on the Chinese Stock Market  [PDF]
Ying Li, Tengfei Jiang
Journal of Mathematical Finance (JMF) , 2017, DOI: 10.4236/jmf.2017.72025
Abstract: This study adopts two nonparametric methods, the activity signature function (ASF) and ratio analysis of cojumps, to test jumps in China’s stock market. Jumps in the stock price, stock-index futures, and volatility of China Securities Index (CSI) 300 index are analyzed using data on the continuous main-contract price of the index. The findings are as follows. First, in the long run, the CSI 300 index process is a continuous process exhibiting jumps at all sampling intervals. In the short run, the index becomes a pure-jump process in times of recession while exhibiting the characteristics of a continuous or even semimartingale process in certain intervals. Second, the stock-index futures process is a continuous process with jumps at all sampling intervals and, in the short run, exhibits the characteristics of a pure-jump process every 6 months. Moreover, the volatility process generally exhibits the characteristics of pure-jump processes. Third, the CSI 300 index price process and the continuous main-contract price process of the CSI 300 stock-index futures are significantly and positively related, with jumps occurring with a time lag of less than 5 minutes; by contrast, the volatility and price processes of the index are nonsignificantly related.
Camptothecin-20(s)-O-[N-(3’α,12’α-dihydroxy-24’-carbonyl-5’β-cholan)]-lysine, a Novel Camptothecin Analogue, Induces Apoptosis towards Hepatocellular Carcinoma SMMC-7721 Cells
Qingyong Li,Wei Qiu,Qiaochu Zhu,Yuangang Zu,Xiaoqiu Deng,Tengfei Zhao,Chunfei Jiang,Li Zhang
Molecules , 2011, DOI: 10.3390/molecules16097803
Abstract: Camptothecin-20(s)-O-[N-(3’α,12’α-dihydroxy-24’-carbonyl-5’β-cholan)]-lysine (B2) is a novel camptothecin analogue. Our previous study had shown that it displayed higher cytoxicity activity towards hepatocellular carcinoma SMMC-7721 cells than camptothecin (CPT) in vitro. In this paper, the underlying mechanism of anti-proliferation of B2 towards SMMC-7721 cells was further examined. Cell growth inhibition of B2 was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay; morphological changes were observed under Laser Scanning Confocal Microscope (LSCM); cell cycle distribution, apoptotic population, changes in mitochondrial membrane potential, intracellular calcium concentration and reactive oxygen species (ROS) production were determined by flow cytometry (FCM). Activities of caspase-3 and caspase-9 were measured, and the expression level of Bcl-2 and Bax proteins were analyzed by Western blot. The results suggested that B2 inhibited SMMC-7721 cell growth by causing cell cycle arrest at the S and G2/M phases, and induced apoptosis involving a mitochondrial pathway. B2 appears to cause a high induction of apoptosis on SMMC-7721 cells in vitro, which suggests it might be a potential drug for cancer therapy.
A Fur-like protein PerR regulates two oxidative stress response related operons dpr and metQIN in Streptococcus suis
Tengfei Zhang, Yi Ding, Tingting Li, Yun Wan, Wei Li, Huanchun Chen, Rui Zhou
BMC Microbiology , 2012, DOI: 10.1186/1471-2180-12-85
Abstract: In the present study, the perR gene deletion mutant ΔperR was constructed in Streptococcus suis serotype 2 strain SC-19, and the mutant strain ΔperR exhibited less sensitivity to H2O2 stress compared to the wild-type. The dpr and metQIN were found to be upregulated in the ΔperR strain compared with SC-19. Electrophoretic mobility shift assays showed that the promoters of dpr and metQIN could be bound by the PerR protein. These results suggest that dpr and metQIN are members of the PerR regulon of S. suis. dpr encodes a Dps-like peroxide resistance protein, and the dpr knockout strains (Δdpr and ΔdprΔperR) were highly sensitive to H2O2. MetQIN is a methionine transporter, and the increased utilization of methionine in the ΔperR strain indirectly affected the peroxide resistance. Using a promoter–EGFP gene fusion reporting system, we found that the PerR regulon was induced by H2O2, and the induction was modulated by metal ions. Finally, we found that the pathogenicity of the perR mutant was attenuated and easily cleared by mice.These data strongly suggest that the Fur-like protein PerR directly regulates dpr and metQIN and plays a crucial role in oxidative stress response in S. suis.
A Revisit to High Thermoelectric Performance of Single-layer MoS2
Zelin Jin,Quanwen Liao,Haisheng Fang,Zhichun Liu,Wei Liu,Zhidong Ding,Tengfei Luo,Nuo Yang
Physics , 2015, DOI: 10.1038/srep18342
Abstract: Both electron and phonon transport properties of single layer MoS2 (SLMoS2) are studied. Based on first-principles calculations, the electrical conductivity of SLMoS2 is calculated by Boltzmann equations. The thermal conductivity of SLMoS2 is calculated to be as high as 116.8 Wm-1K-1 by molecular dynamics (MD) simulations. The predicted value of ZT is as high as 0.26 at 500K. As the thermal conductivity could be reduced largely by phonon engineering, there should be a high possibility to enhance ZT in the SLMoS2-based materials.
Deep Profiling of the Novel Intermediate-Size Noncoding RNAs in Intraerythrocytic Plasmodium falciparum
Chunyan Wei, Tengfei Xiao, Peng Zhang, Zhensheng Wang, Xiaowei Chen, Lianhui Zhang, Meixue Yao, Runsheng Chen, Heng Wang
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0092946
Abstract: Intermediate-size noncoding RNAs (is-ncRNAs) have been shown to play important regulatory roles in the development of several eukaryotic organisms. However, they have not been thoroughly explored in Plasmodium falciparum, which is the most virulent malaria parasite infecting human being. By using Illumina/Solexa paired-end sequencing of an is-ncRNA-specific library, we performed a systematic identification of novel is-ncRNAs in intraerythrocytic P. falciparum, strain 3D7. A total of 1,198 novel is-ncRNA candidates, including antisense, intergenic, and intronic is-ncRNAs, were identified. Bioinformatics analyses showed that the intergenic is-ncRNAs were the least conserved among different Plasmodium species, and antisense is-ncRNAs were more conserved than their sense counterparts. Twenty-two novel snoRNAs were identified, and eight potential novel classes of P. falciparum is-ncRNAs were revealed by clustering analysis. The expression of randomly selected novel is-ncRNAs was confirmed by RT-PCR and northern blotting assays. An obvious different expressional profile of the novel is-ncRNA between the early and late intraerythrocytic developmental stages of the parasite was observed. The expression levels of the antisense RNAs correlated with those of their cis-encoded sense RNA counterparts, suggesting that these is-ncRNAs are involved in the regulation of gene expression of the parasite. In conclusion, we accomplished a deep profiling analysis of novel is-ncRNAs in P. falciparum, analysed the conservation and structural features of these novel is-ncRNAs, and revealed their differential expression patterns during the development of the parasite. These findings provide important information for further functional characterisation of novel is-ncRNAs during the development of P. falciparum.
Palaeoclimate Reconstruction of Middle Permian in Tuha Basin: Evidence from the Fossil Wood Growth Rings

魏信祥,张雄华,黄 兴,栾腾飞
Wei Xinxiang
, Zhang Xionghua, Huang Xing, Luan Tengfei

地球科学(中国地质大学学报) , 2016, DOI: 10.3799/dqkx.2016.525
Abstract: 收集木化石年轮数据有助于古气候重建工作.首次通过对吐哈盆地北东缘中二叠统塔尔郎组中发现的木化石的年轮统计分析,还原了吐哈盆地中二叠世的古气候演化过程.木化石的年轮分析表明:该区中二叠世整体处于季节性明显的北亚热带,气候整体相对温暖,但出现过间歇性相对炎热的气候.木化石较低的晚材率以及部分年轮早材到晚材为过渡突变,反映树木生长时期季节性非常明显,夏季湿热,冬季干冷,为典型的亚热带季风型气候.木化石具较高的平均敏感度(MS平均可达0.4),显示树木生长期间受季风气候的影响,环境非常不稳定,每年大气降水量有很大的变化.连续年轮宽度的宽窄不一以及伪年轮的存在,表明当时气候变化频繁,整体较为湿润,但也具有干旱-半干旱的波动.
The collection of fossil wood growth rings data is helpful for rebuilding paleoclimate. Based on the statistical analysis of fossil wood growth rings from Middle Permian Taerlang Formation in the northeast edge of Tuha basin, the paleoclimate evolution of Middle Permian is reconstructed for the first time. The analysis of fossil wood growth rings shows that this area was subject to north subtropical climate with obvious seasonal variations during the Middle Permian. The paleoclimate was relatively warm, but intermittent hot climate had occurred. The low percentage of latewood and the abrupt transition between earlywood and latewood of some growth rings reflect that the seasonal variations were very obvious during the period of trees growth. The paleoclimate was prevailed by a subtropical monsoon climate with hot and humid summer and dry and cold winter. The relatively high mean sensitivity (MS average of 0.4) of fossil woods indicates that trees were influenced by monsoon climate during the growth period, and the environment was very unstable with uneven annual precipitation. The change of consecutive growth ring width and the existence of false rings implies that the climate changed frequently and generally was humid with arid and semi-arid fluctuations
Precursor-Like Anomalies prior to the 2008 Wenchuan Earthquake: A Critical-but-Constructive Review
Tengfei Ma,Zhongliang Wu
International Journal of Geophysics , 2012, DOI: 10.1155/2012/583097
Abstract: Results published since the last three years on the observations of the precursor-like anomalies before the May 12, 2008, Wenchuan, 8.0 earthquake are collected and analyzed. These retrospective case studies would have provided heuristic clues about the preparation process of this inland great earthquake and the predictability of this destructive event if the standards for the rigorous test of earthquake forecast schemes were strictly observed. At least in some of these studies, however, several issues still need to be further examined to confirm or falsify the connection of the reported observations with the Wenchuan earthquake. Some of the problems are due to the inevitable limitation of observational infrastructure at the recent time, but some of the problems are due to the lack of communication about the test of earthquake forecast schemes. For the interdisciplinary studies on earthquake forecast, reminding of the latter issue seems of special importance for promoting the works and cooperation in this field.
On the Improvement of Accounting Information Quality by Perfecting Invoice Management
Tengfei Chai,Guijiang Wen
International Journal of Business and Management , 2010, DOI: 10.5539/ijbm.v5n2p194
Abstract: This paper conducts a statistical analysis on the cheating measures adopted in the financial reports of Chinese quoted companies based on relevant information revealed in the punishment proclamations issued by China Securities Regulatory Committee from 2002 to 2008, revealing fictitious transaction as the main cheating measure. In the end, some countermeasures are put forward.
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