An Improved Method of Maximum Power Point Tracking Strategy for Wind Power Conversion System

CHEN Ran,CHEN Jie,CHEN Jia-wei,CHEN Zhi-hui,GONG Chun-ying,YAN Yang-guang 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

The turbine speed loop adjustment is the key link of the designing of the controller for the fixed pitch variable speed wind energy conversion systems (WECS). Because of the strong nonlinear, big inertia and mechanical damping characteristics, it’s difficult to designing the controller of the wind power systems. In this paper, a small signal model is present, and based on the analyzing; a wind turbine speed loop regulator is designed. Then, a method of tracking the peak power conversion system is proposed, which is independent of the turbine parameters and air density. At last, simulation system is built, and the results of the simulation experiments show that, the performance of the controller algorithm meet the requirements of the MPPT without wind measurement.

Combined Assessment of Serum Alpha-Synuclein and Rab35 is a Better Biomarker for Parkinson’s Disease

Hung-Li Wang,Chin-Song Lu,Tu-Hsueh Yeh,Yu-Ming Shen,Yi-Hsin Weng,Ying-Zu Huang,Rou-Shayn Chen,Yu-Chuan Liu,Yi-Chuan Cheng,Hsiu-Chen Chang,Ying-Ling Chen,Yu-Jie Chen,Yan-Wei Lin,Chia Chen Hsu,Huang-Li 대한신경과학회 2019 Journal of Clinical Neurology Vol.15 No.4

Background and Purpose It is essential to develop a reliable predictive serum biomarker for Parkinson’s disease (PD). Te accumulation of alpha-synuclein (αSyn) and up-regulated expression of Rab35 participate in the etiology of PD. Te purpose of this investigation was to determine whether the combined assessment of serum αSyn and Rab35 is a useful predictive biomarker for PD. Methods Serum levels of αSyn or Rab35 were determined in serum samples from 59 sporadic PD patients, 19 progressive supranuclear palsy (PSP) patients, 20 multiple system atrophy (MSA) patients, and 60 normal controls (NC). Receiver operating characteristics (ROC) curves were calculated to determine the diagnostic accuracy of αSyn or/and Rab35 in discriminating PD patients from NC or atypical parkinsonian patients. Results The levels of αSyn and Rab35 were increased in PD patients. The serum level of Rab35 was positively correlated with that of αSyn in PD patients. Compared to analyzing αSyn or Rab35 alone, the combined analysis of αSyn and Rab35 produced a larger area under the ROC curve and performed better in discriminating PD patients from NC, MSA patients, or PSP patients. When age was dichotomized at 55, 60, 65, or 70 years, the combined assessment of αSyn and Rab35 for classifying PD was better in the group below the cutof age than in the group above the cutof age. Conclusions Combined assessment of serum αSyn and Rab35 is a better biomarker for discriminating PD patients from NC or atypical parkinsonian patients, and is a useful predictive biomarker for younger sporadic PD patients.

Power and Promise of Ubiquitin Carboxyl-terminal Hydrolase 37 as a Target of Cancer Therapy

Chen, Yan-Jie,Ma, Yu-Shui,Fang, Ying,Wang, Yi,Fu, Da,Shen, Xi-Zhong Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.4

Ubiquitin carboxyl-terminal hydrolase 37 (UCH37, also called UCHL5), a member of the deubiquitinating enzymes, can suppress protein degradation through disassembling polyubiquitin from the distal subunit of the chain. It has been proved that UCH37 can be activated by proteasome ubiqutin chain receptor Rpn13 and incorporation into the 19S complex. UCH37, which has been reported to assist in the mental development of mice, may play an important role in oncogenesis, tumor invasion and migration. Further studies will allow a better understanding of roles in cell physiology and pathology, embryonic development and tumor formation, hopefully providing support for the idea that UCH37 may constitute a new interesting target for the development of anticancer drugs.

Current state of research about acupuncture for the treatment of COVID-19: A scoping review

Chen Chen,Jie Zhan,Hao Wen,Xiaojing Wei,Lu Ding,Chenyang Tao,Cui Li,Peiming Zhang,Yuyuan Tang,Jing-chun Zeng,Li-ming Lu 한국한의학연구원 2021 Integrative Medicine Research Vol.10 No.-

Background Since the outbreak of coronavirus disease (COVID-19), acupuncture has been widely used in the treatment of COVID-19. The research community has responded rapidly and has already published many research articles about this topic. Methods We searched PubMed, Embase, Cochrane Library as well as CNKI, Wanfang and VIP from January 1, 2020 to July 31, 2021. The dates of publication, language of publication, methodological characteristics and the key findings were analyzed separately. The data are presented as bar graphs, structured tables and figures. Results In this scoping review, 16 research articles were included: 7 case reports, 6 observational studies, 1 review, 1 RCT and 1 nonrandomized clinical trial. The majority of the articles (81.3%) were published by Chinese scholars, 12.5% articles were by scholars in the United States, and 6.3% articles were by scholars in Iran. The included studies reported that acupuncture could alleviate the symptoms of COVID-19 patients, shorten their hospitalization days, and is effective for the elderly. There were no side effects reported. The most frequent acupoints used were LI4, PC6, ST36 and KI3. They reported many obstacles in implementing acupuncture therapy for treating COVID-19 patients. Conclusion Acupuncture has a good effect for the treatment of COVID-19, but high-quality evidence support is still lacking. Coupled with the difficulties that acupuncturists experienced during the process of treatment, the promotion of acupuncture treatment for COVID-19 faces many obstacles. Background Since the outbreak of coronavirus disease (COVID-19), acupuncture has been widely used in the treatment of COVID-19. The research community has responded rapidly and has already published many research articles about this topic. Methods We searched PubMed, Embase, Cochrane Library as well as CNKI, Wanfang and VIP from January 1, 2020 to July 31, 2021. The dates of publication, language of publication, methodological characteristics and the key findings were analyzed separately. The data are presented as bar graphs, structured tables and figures. Results In this scoping review, 16 research articles were included: 7 case reports, 6 observational studies, 1 review, 1 RCT and 1 nonrandomized clinical trial. The majority of the articles (81.3%) were published by Chinese scholars, 12.5% articles were by scholars in the United States, and 6.3% articles were by scholars in Iran. The included studies reported that acupuncture could alleviate the symptoms of COVID-19 patients, shorten their hospitalization days, and is effective for the elderly. There were no side effects reported. The most frequent acupoints used were LI4, PC6, ST36 and KI3. They reported many obstacles in implementing acupuncture therapy for treating COVID-19 patients. Conclusion Acupuncture has a good effect for the treatment of COVID-19, but high-quality evidence support is still lacking. Coupled with the difficulties that acupuncturists experienced during the process of treatment, the promotion of acupuncture treatment for COVID-19 faces many obstacles.

Recent Development on Photocatalysts and Membrane Processes for Photoreduction of CO2 into C1 Solar Fuels

Chen Jian Jie,Oh Pei Ching,Saleh Syafiqa Bt M. 한국화학공학회 2024 Korean Journal of Chemical Engineering Vol.41 No.3

This review paper delineates an overview of recent developments on photocatalytic processes for the photoreduction of CO 2 into C1 solar fuels including methanol and methane. The effi ciency of the novel processes reported is compared in terms of the yields of C1 fuels. Brief introduction on synthetic protocols of the cited photocatalysts employed for the photoreduction of CO 2 into C1 fuels is succinctly discoursed in this work. Furthermore, an additional review section is also included for summarizing the recently published ideas of diff erent confi gurations of photocatalytic membrane processes utilized for the separation of CO 2 converted C1 products from the reaction solvent. It was concluded that there is still substantial room of improvement for both newly developed photocatalytic systems and membrane processes in terms of C1 yield and the fuel separation effi ciency, respectively. Despite its potential as a promising green candidate used for carbon capture and utilization, additional studies are still necessary prior to its scalable application in industry. These studies should take a deep dive into the optimization of both photocatalytic and membrane separation processes, largely by development of novel photocatalytic systems that are highly effi cient in CO 2 conversion and membrane systems that are selective toward desired fuel products.

A Secret Sharing Scheme Based on AES

Jie Cui,Lei Chen,Yiming Zhang,Zhiqiang Xie,Hong Zhong 보안공학연구지원센터 2014 International Journal of Security and Its Applicat Vol.8 No.6

In order to solve the key setting difficulty and the key security problem in the file encryption, key distributed storage technology may be a proper choice to help improve the safety of the key. In the paper, a novel secret sharing scheme is proposed by AES encryption algorithm for file confidentiality, dynamic key generation mechanism to generate keys, multi-secret-sharing ideas on key pre-treatment, using Shamir threshold scheme for secret dispersed storage. Finally, a few tests are carried out and the test results suggest that the efficiency of the whole scheme is good.

Male hypogonadism caused by a homozygous missense mutation of the LHB gene

( Jie Chen ),( Wen-ting Yi ),( Yuan-Qing Cui ),( Wen-ting Wang ),( Xiong Wang ) 대한내과학회 2021 The Korean Journal of Internal Medicine Vol.36 No.6

Microstructure and Abrasive Wear Properties of Fe-Cr-C Hardfacing Alloy Cladding Manufactured by Gas Tungsten Arc Welding (GTAW)

Jie-Hao Chen,Chih-Chun Hsieh,Pei-Shing Hua,Chia-Ming Chang,Chi-Ming Lin,Paxon Ti-Yuan Wu,Weite Wu 대한금속·재료학회 2013 METALS AND MATERIALS International Vol.19 No.1

A series of Fe-Cr-C hardfacing alloys is deposited by gas tungsten arc welding and subjected to abrasive wear testing. Pure Fe with various amounts of CrC (Cr:C=4:1) powders are mixed as the fillers and used to deposit hardfacing alloys on low carbon steel. Depending on the various CrC additions to the alloy fillers,the claddings mainly contain hypoeutectic, near eutectic, or hypereutectic microstructures of austenite γ-Fe phase and (Cr,Fe)7C3 carbides on hardfacing alloys, respectively. When 30% CrC is added to the filler, the finest microstructure is achieved, which corresponds to the γ-Fe+(Cr,Fe)7C3 eutectic structure. With the addition of 35% and 40% CrC to the fillers, the results show that the cladding consists of the massive primary (Cr,Fe)7C3 as the reinforcing phase and interdendritic Fe+(Cr,Fe)7C3 eutectics as the matrix. The (Cr,Fe)7C3 carbide-reinforced claddings have high hardness and excellent wear resistance under abrasive wear test conditions. Concerning the abrasive wear feature observable on the worn surface, the formation and fraction of massive primary (Cr,Fe)7C3 carbides predominates the wear resistance of hardfacing alloys. Abrasive particles result in continuous plastic grooves when the cladding has primary γ-Fe phase in a hypoeutectic structure.

Self-healing capacity of damaged rock salt with different initial damage

Chen, Jie,Kang, Yanfei,Liu, Wei,Fan, Jinyang,Jiang, Deyi,Chemenda, Alexandre Techno-Press 2018 Geomechanics & engineering Vol.15 No.1

In order to analyze the healing effectiveness of rock salt cracks affected by the applied stresses and time, we used the ultrasonic technology to monitor the ultrasonic pulse velocity (UPV) variations for different initial stress-damaged rock salts during self-healing experiments. The self-healing experiments were to create different conditions to improve the microcracks closure or recrystallized, which the self-healing effect of damaged salt specimens were analyzed during the recovery period about 30 days. We found that: The ultrasonic pulse velocity of the damaged rock salts increases rapidly during the first 9 days recovery, and the values gradually increase to reach constant values after 30 days. The damaged value and the healed value were identified based on the variation of the wave velocity. The damaged values of the specimens that are subject to higher initial damage stress are still keeping in large after 30 days recovery under the same recovery condition It is interesting that the damage and the healing were not in the linear relationship, and there also existed a damage threshold for salt cracks healing ability. When the damage degree is less than the threshold, the self-healing ratio of rock salt is increased with the increase in damage degree. However, while the damage degree exceeds the threshold, the self-healing ratio is decreased with the increase in damage.

The mechanical properties of rock salt under cyclic loading-unloading experiments

Chen, Jie,Du, Chao,Jiang, Deyi,Fan, Jinyang,He, Yi Techno-Press 2016 Geomechanics & engineering Vol.10 No.3

Rock salt is a near-perfect material for gas storage repositories due to its excellent ductility and low permeability. Gas storage in rock salt layers during gas injection and gas production causes the stress redistribution surrounding the cavity. The triaxial cyclic loading and unloading tests for rock salt were performed in this paper. The elastic-plastic deformation behaviour of rock salt under cyclic loading was observed. Rock salt experienced strain hardening during the initial loading, and the irreversible deformation was large under low stress station, meanwhile the residual stress became larger along with the increase of deviatoric stress. Confining pressure had a significant effect on the unloading modulus for the variation of mechanical parameters. Based on the theory of elastic-plastic damage mechanics, the evolution of damage during cyclic loading and unloading under various confining pressure was described.