Recent Development of Laboratory-made Solid-phase Microextraction Fibers on the Application of Food Safety Analysis

Jingbin Zeng,Jinmei Chen,Wenfeng Chen,Xiaoli Huang,Liangbi Chen,Xi Chen 한국식품과학회 2009 Food Science and Biotechnology Vol.18 No.3

Solid-phase microextraction (SPME) has gained widespread acceptance in sample pretreatment due to its solventfree and easy-to-operate properties. SPME fibers are considered as a key part of SPME technique, since it primarily determines the extraction performance of the method including sensitivity, selectivity, and reproducibility. Generally speaking, target analyte with different chemical property requires fiber coating that has the best affinity towards it. Due to the lack of varieties of commercial fibers available currently, considerable efforts have been recently made to develop tailor-made fibers to fulfill increasing demands of different analysis. This paper concisely classify some SPME fiber preparation approaches such as solgel technology, physical deposition, molecularly imprinted technique, and their respective application in food safety analysis.

IGCT Self-Protection Strategy for IGCT Converters

Hong Zeng,Xiulin Chen,Yongmin Chen,Xuejun Pan,Shunbiao Zhang,Fanglin Chen,Wenbin Zeng 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

The high-power semiconductor IGCT is widely used in two-level or three-level IGCT converters and for these converters a comprehensive system-protection strategy may be used to protect the IGCT. But there are still some problems resulted from signal transmission delays, such as incorrect timing, low response speeds, second breakdown and those problems can result in IGCT overload failure, bridge-arm shoot-through and other consequences. In this paper, the anode voltage and current parameters gained from the IGCT device are studied as protection reference in a new GCT gate drive unit. The gate drive unit can control and process the signal logic, and execute safe and reliable switching action. The signal is simultaneously feed back to the host computer in IGCT converters to perform the switching control of other devices. This new gate unit can effectively reduce device failure rates and improve the reliability of IGCT converters systems, while reducing operating costs.

First record of the spider genus Phobetinus (Araneae: Mimetidae) in China, with the description of a new species

Chen Zeng,Muhammad Irfan,Xian-Jin Peng 국립중앙과학관 2019 Journal of Asia-Pacific Biodiversity Vol.12 No.4

The mimetid spider genus Phobetinus Simon, 1895, is recorded in China for the first time, and a newspecies, Phobetinus contrarius sp. nov. (_\), is described from Yunnan, southwestern China.

Experimental Investigations on VIV of Bridge Deck Sections: A Case Study

Zeng-shun Chen,Si-meng Liu,Xianfeng Yu,Cun-ming Ma,Lei Liu 대한토목학회 2017 KSCE Journal of Civil Engineering Vol.21 No.7

In this paper, the Vortex Induced Vibrations (VIVs) of bridge deck sections of the Hong Kong-Zhuhai-Macao Bridge were investigated experimentally. Aeroelastic tests for the bridge deck of two scale ratios (1:20 model and 1:50 model) under different wind attack angles, wind speeds, and damping ratios were performed. Accessory and windbreak effects on the VIVs of the bridge deck were also carried out. The experimental results show that the accessory and windbreak tend to enlarge the VIVs of the bridge deck. Furthermore, the most unfavorable wind attack angle is 5o. At this attack angle and low damping ratios, the VIVs of the bridge deck are significant and much larger than the allowable value. In addition, the VIVs of the bridge deck decrease with increasing the damping ratios (Particularly, at large damping ratios, the VIVs were well suppressed). This study provides a guideline for the designs of long span flexible bridges on suppressing the VIVs of the bridges.

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.

Smooth Torque Speed Characteristic of Switched Reluctance Motors

Zeng, Hui,Chen, Zhe,Chen, Hao The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.2

The torque ripple of switched reluctance motors (SRMs) is the main disadvantage that limits the industrial application of these motors. Although several methods for smooth-toque operation (STO) have been proposed, STO works well only within a certain torque and speed range because of the constraints of the supply voltage and peak current. Based on previous work that sought to expand the STO range, a scheme is developed in this study to determine the maximum smooth torque range at each speed. The relationship between the maximum smooth torque and speed is defined as the smooth torque speed characteristics (STSC), a concept similar to torque speed characteristics (TSC). STSC can be utilized to evaluate torque utilization by comparing it with TSC. Thus, the concept benefits the special design of SRMs, especially for the generation of smooth torque. Furthermore, the torque sharing function (TSF) derived from the proposed method can be applied to STO, which produces a higher smooth torque over a wider speed range in contrast to four typical TSFs. TSimulation and experimental results verify the proposed method.

Smooth Torque Speed Characteristic of Switched Reluctance Motors

Hui Zeng,Zhe Chen,Hao Chen 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.2

The torque ripple of switched reluctance motors (SRMs) is the main disadvantage that limits the industrial application of these motors. Although several methods for smooth-toque operation (STO) have been proposed, STO works well only within a certain torque and speed range because of the constraints of the supply voltage and peak current. Based on previous work that sought to expand the STO range, a scheme is developed in this study to determine the maximum smooth torque range at each speed. The relationship between the maximum smooth torque and speed is defined as the smooth torque speed characteristics (STSC), a concept similar to torque speed characteristics (TSC). STSC can be utilized to evaluate torque utilization by comparing it with TSC. Thus, the concept benefits the special design of SRMs, especially for the generation of smooth torque. Furthermore, the torque sharing function (TSF) derived from the proposed method can be applied to STO, which produces a higher smooth torque over a wider speed range in contrast to four typical TSFs. TSimulation and experimental results verify the proposed method.

ARCHITECTURE OF FLOWER-LIKE rGO/CNTs-LOADED CuxO NANOPARTICLES AND ITS PHOTOCATALYTIC PROPERTIES

BIN ZENG,XIAOHUA CHEN,XUTAO NING,CHUANSHENG CHEN,HUI LONG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2013 NANO Vol.8 No.5

Novel flower-like composite architecture was successfully synthesized by spray drying and post-calcinating method for the first time. Scanning electron microscopy and transmission electron microscopy observations confirmed that reduced graphene oxides/carbon nanotubes hybrid (rGO/CNTs) formed a flower-like micrometer structure and Cu2O, CuO (CuxO, x = 1 or 2) nanoparticles were decorated inside them. The photocatalytic properties were further investigated by evaluating the photodegradation of a pollutant methyl orange (MO). The experimental results indicated that this novel architecture enhanced photocatalytic performance with 96.2% decomposition of MO after 25 min in the presence of H2O2 under visible light irradiation, which was much higher than that of CuxO powders (33.2%). This could be attributed to the more efficient adsorption of MO molecules on flower-like rGO/CNTs and provide a high concentration of MO near to the CuxO nanoparticles, thus promoting the photocatalytic degradation process.

PAPG: Private Aggregation Scheme based on Privacy-preserving Gene in Wireless Sensor Networks

( Weini Zeng ),( Peng Chen ),( Hairong Chen ),( Shiming He ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.9

This paper proposes a privacy-preserving aggregation scheme based on the designed P-Gene (PAPG) for sensor networks. The P-Gene is constructed using the designed erasable data-hiding technique. In this P-Gene, each sensory data item may be hidden by the collecting sensor node, thereby protecting the privacy of this data item. Thereafter, the hidden data can be directly reported to the cluster head that aggregates the data. The aggregation result can then be recovered from the hidden data in the cluster head. The designed P-Genes can protect the privacy of each data item without additional data exchange or encryption. Given the flexible generation of the P-Genes, the proposed PAPG scheme adapts to dynamically changing reporting nodes. Apart from its favorable resistance to data loss, the extensive analyses and simulations demonstrate how the PAPG scheme efficiently preserves privacy while consuming less communication and computational overheads.

Magnetic Flux Leakage Image Enhancement using Bidimensional Empirical Mode Decomposition with Wavelet Transform Method in Oil Pipeline Nondestructive Evaluation

Liang Chen,Jingcheng Li,Yakai Zeng,Yongqiang Chen,Wei Liang 한국자기학회 2019 Journal of Magnetics Vol.24 No.3

The magnetic flux leakage (MFL) method is the most widely used and cost-effective inspection technique for oil pipeline. However, noise is inevitable in the process of data collection; thus, the image enhancement method can be more intuitive to identify the defects in an oil pipeline MFL inspection. In this paper, the bidimensional empirical mode decomposition (BEMD) method has been used to study oil pipeline MFL images. The MFL image is decomposed into a finite number of two-dimensional intrinsic mode functions (BIMF) and a residual component by the BEMD. The wavelet transform (WT) was used to remove the noise in the BIMF. The image was then reconstructed by retaining the basic information and removing the noise. The results show that the noise is effectively removed and the detail of the MFL image is well preserved. Thus, the BEMD with WT method for oil pipeline MFL image enhancement is better than the mean filtering method and the WT method.