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Modeling and Control Method for High-power Electromagnetic Transmitter Power Supplies
Yu, Fei,Zhang, Yi-Ming The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.4
High-power electromagnetic transmitter power supplies are an important part of deep geophysical exploration equipment. This is especially true in complex environments, where the ability to produce a highly accurate and stable output and safety through redundancy have become the key issues in the design of high-power electromagnetic transmitter power supplies. To solve these issues, a high-frequency switching power cascade based emission power supply is designed. By combining the circuit averaged model and the equivalent controlled source method, a modular mathematical model is established with the on-state loss and transformer induction loss being taken into account. A triple-loop control including an inner current loop, an outer voltage loop and a load current forward feedback, and a digitalized voltage/current sharing control method are proposed for the realization of the rapid, stable and highly accurate output of the system. By using a new algorithm referred to as GAPSO, which integrates a genetic algorithm and a particle swarm algorithm, the parameters of the controller are tuned. A multi-module cascade helps to achieve system redundancy. A simulation analysis of the open-loop system proves the accuracy of the established system and provides a better reflection of the characteristics of the power supply. A parameter tuning simulation proves the effectiveness of the GAPSO algorithm. A closed-loop simulation of the system and field geological exploration experiments demonstrate the effectiveness of the control method. This ensures both the system's excellent stability and the output's accuracy. It also ensures the accuracy of the established mathematical model as well as its ability to meet the requirements of practical field deep exploration.
Prevalence and Risk Factors of Cerebral Small Vessel Disease in a Chinese Population-Based Sample
Fei Han,Fei-Fei Zhai,Quan Wang,Li-Xin Zhou,Jun Ni,Ming Yao,Ming-Li Li,Shu-Yang Zhang,Li-Ying Cui,Zheng-Yu Jin,Yi-Cheng Zhu 대한뇌졸중학회 2018 Journal of stroke Vol.20 No.2
Background and Purpose Epidemiological data of cerebral small vessel disease (CSVD) in the general population of China are lacking. We report on the prevalence of lacunes, white matter hyperintensity (WMH), and cerebral microbleeds (CMBs) in a community-based sample in China and compare the results with those of other studies. Methods This was a cross-sectional analysis of the population-based Shunyi Study in China. A total of 1,211 stroke-free participants (mean age, 55.6±9.3 years; 37.4% men) with available 3 Tesla (3T) magnetic resonance images were included in this analysis. Demographic information and risk factor data were assessed. The overall and age-specific prevalence of lacunes, WMH, and CMBs was evaluated. Associations between cardiovascular risk factors and the presence of these lesions were analyzed by multiple logistic regression. Results Our study showed a prevalence of 14.5% for lacunes, 72.1% for periventricular hyperintensity (PVH), 65.4% for deep white matter hyperintensity (DWMH), and 10.6% for CMBs. When compared with other community-based samples, individuals in the same age group showed a higher burden of lacunes and a relatively lower prevalence of CMBs. Advanced age was independently associated with the prevalence of these CSVD markers, while the presence of hypertension increased the risk of lacunes, PVH/DWMH, and CMBs in deep or infratentorial locations. Conclusions A higher burden of lacunes but a relatively lower prevalence of CMBs was observed in this Chinese population. This notable result highlights the challenge of CSVD prevention in China. Chinese have a risk factor profile for CSVD similar to those in other populations.
Fei-Fei Si,Lu Liu,Hai-Mei Li,Li Sun,Qing-Jiu Cao,Hanna Lu,Yu-Feng Wang,Qiu-Jin Qian 대한신경정신의학회 2021 PSYCHIATRY INVESTIGATION Vol.18 No.7
Objective Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder in children and adolescents. The present study investigated the cortical morphology features and their relationship with working memory (WM). Methods In the present study, a total of 36 medication naïve children with ADHD (aged from 8 to 15 years) and 36 age- and gendermatched healthy control (HC) children were included. The digit span test was used to evaluate WM. The magnetic resonance imaging (MRI) was used to examine the characteristics of cortical morphology. Firstly, we compared the cortical morphology features between two groups to identify the potential structural alterations of cortical volume, surface, thickness, and curvature in children with ADHD. Then, the correlation between the brain structural abnormalities and WM was further explored in children with ADHD. Results Compared with the HC children, the children with ADHD showed reduced cortical volumes in the left lateral superior temporal gyrus (STG) (p=6.67×10-6) and left anterior cingulate cortex (ACC) (p=3.88×10-4). In addition, the cortical volume of left lateral STG was positively correlated with WM (r=0.36, p=0.029). Conclusion Though preliminary, these findings suggest that the reduced cortical volumes of left lateral STG may contribute to the pathogenesis of ADHD and correlate with WM in children with ADHD.
Analyzing Chinese Online P2P Financial Product Purchase Decisions Utilizing the Framing Effect 7)
Yu Fei Shang,김순홍 한국유통과학회 2015 유통과학연구 Vol.13 No.10
Purpose – This study examines Chinese P2P investment decision processes from a behavioral economics approach. Research design, data, and methodology – We analyze the online P2P investment product purchase decisions of 241 respondents in China, March 2015 to May 2015. T-tests were conducted to determine whether the framing effect influenced investor investment preferences. The Association Rule was used to identify the framing effect of respondent demographic characteristics on joint decisions regarding stable or risky investment products. Results – There are significant differences between the two groups (positive framing and negative framing) and their product- choosing behavior. In the positive framing group, female investors, young investors, investors with non-financial occupations and with limited or no experience, preferred stable P2P investment products. In contrast, in the negative framing group, investors with extensive investment experience preferred risky investment products. Conclusions – The framing effect influences investor choices in online P2P investment products. It is necessary to implement comprehensive supervision and full information disclosure regarding P2P investment products. P2P investment websites can also adopt different marketing strategies according to investor gender and age.
Yu-Lin Dai,Meng-Dan Qiao,Peng Yu,Fei Zheng,Hao Yue,Shu-Ying Liu 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.2
Background: This article aims to compare and analyze the contents of ginsenosides in ginseng ofdifferent plant ages from different localities in China. Methods: In this study, 77 fresh ginseng samples aged 2e4 years were collected from 13 differentcultivation regions in China. The content of eight ginsenosides (Rg3, Rc, Rg1, Rf, Rb2, Rb1, Re, and Rd) wasdetermined using rapid resolution liquid chromatography coupled with quadrupoleetime-of-flighttandem mass spectrometry (RRLC-Q-TOF MS/MS) to comparatively evaluate the influences of cultivationregion and age. Results: Ginsenoside contents differed significantly depending on age and cultivation region. The contentsof ginsenosides Re, Rc, Rg1, Rg3, and Rf increased with cultivation age, whereas that of ginsenoside Rb1peaked in the third year of cultivation. Moreover, the highest ginsenoside content was obtained fromChangbai (19.36 mg/g) whereas the lowest content was obtained from Jidong (12.05 mg/g). Ginseng fromJilin Province contained greater total ginsenosides and was richer in ginsenoside Re than ginseng of thesame age group in Heilongjiang and Liaoning provinces, where Rb1 and Rg1 contents were relatively high. Conclusion: In this study, RRLC-Q-TOF MS/MS was used to analyze ginsenoside contents in 77 ginsengsamples aged 2e4 years from different cultivation regions. These patterns of variation in ginsenosidecontent, which depend on harvesting location and age, could be useful for interested parties to chooseginseng products according to their needs.
Patent citations and knowledge spillovers: an analysis of Chinese patents registered in the USA
Fei Yu,Yanrui Wu 기술경영경제학회 2014 ASIAN JOURNAL OF TECHNOLOGY INNOVATION Vol.22 No.1
This paper examines US patent citation data and analyses how different firms in China affect knowledge spillovers. Patents granted by the US patent office to applicants located in China are collected along with their citation counts. Two kinds of patent citations, namely citations of previous patents and those of non-patent literature, are used to measure knowledge flows. In the empirical analysis, the negative binomial and zero-inflated count models are considered. The regression results suggest the existence of heterogeneity among firms of different ownership. In terms of knowledge spillovers, the US multinational corporations perform better than those from other western countries; Taiwanese companies outperform their counterparts from Hong Kong and Chinese private corporations contribute more than Chinese state-owned enterprises. These results have important policy implications for the development of a knowledge-intensive economy in China.
Discrimination Index of Expansive Rock and Its Suitability
( Yu Fei ),( Sichang Li ),( Zhe Zhou ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2
Through the analysis of the existing expansive rock discriminant index, it can be classified into three types: rock material index, rock powder material index and comprehensive index. By analyzing the essential difference, this is diagenesis, between expansive rock and expansive soil, it is considered that the classification criteria for expansive rock in actual engineering should consider its expansion potential, diagenetic cementation and engineering characteristics, and it should be simple, effective, economical and reasonable. Finally, based on the above principles and comprehensive consideration of each discriminant index, a discriminating index and classification is proposed with the free expansion rate and the drying saturated moisture absorption rate of the rock mass as the initial judging and natural expansive pressure and rate as detailed and final judging criteria. Through the discriminating of 10 samples of a high-speed rail project, it is considered that this discriminating index and classification criteria are feasible.
GRAPHENE AS TUNABLE STATIONARY PHASE ADDITIVE FOR ENANTIOSEPARATION
FEI-YUE TU,LIN-YAN YU,JIN-GANG YU,XIAOQING CHEN,QIANG FU,FEI-PENG JIAO,ZHI-GUANG PENG,TING ZHANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2013 NANO Vol.8 No.6
Graphene-based biosensor and chiral sensor have made significant progress in recent years. Because of the similarity of the optical enantiomers, enantioseparation is perhaps the most subtle to achieve. Developing more effectively chiral separation techniques based on graphene is highly desirable. Herein, pristine graphene was prepared and then applicated to assist resolution of two racemic drugs of propranolol and ofloxacin using thin-layer chromatography (TLC). In comparison with TLC chiral separation by only using pure D-(-)-tartaric acid as a selector with relatively low degree of separation, a mixture of graphene and D-(-)-tartaric acid is more attractive, efficient and ready available. The high specific resolution ability for racemic compounds aided by graphene might allow its potential application in future chiral separation technologies.
Yu-Lin Dai,Yun-Fei Jiang,Yu-Hang Nie,Yu-An Lu,Min-Cheol Kang,You-Jin Jeon 제주대학교 해양과학연구소 2020 해양과환경연구소 연구논문집 Vol.44 No.-
In our previous study, the anticancer effect of the active fucoidan (JHCF4) isolated from acid-processed Sargassum fusiformis was evaluated. In this study, the liver-protective effects of JHCF4 against ethanol-induced Chang liver cell damage and apoptosis-related responses were investigated. Furthermore, the low cytotoxicity and high cell viability of JHCF4 against ethanol-induced cell damage, as well as its protective effect against ethanol-induced cell apoptosis, were observed via nuclear staining with Hoechst 33342 in Chang liver cells. Additionally, the treatment of the 72 h post-fertilization (hpf) zebrafish model with JHCF4 increased the ethanol-stimulated survival rates as well as decreased oxidative stress, lipid peroxidation, and cell death levels. JHCF4 was found to significantly decrease steatosis production in the 128 hpf zebrafish model by Oil Red O staining, as well as attenuate the malondialdehyde and increase the glutathione contents, compared with the untreated group. These results demonstrate that JHCF4 has a potential hepato-protective effect against ethanol-induced damage both in vitro and in vivo.