중국 Changzhou댐의 방수로 운용에 따른 어류밀도와 분포에 관한 음향조사

( Xi Chang Tan ),강명희 ( Myoung Hee Kang ),( Jiang Ping Tao ),( Xin Hui Li ),( Dao Ming Huang ) 한국수산과학회(구 한국수산학회) 2011 한국수산과학회지 Vol.44 No.4

Hydroacoustic surveys were performed to clarify the density and spatial distribution of fish upstream and downstream of Changzhou Dam in the Pearl River, China, with regard to the condition of the spillways. Fish were densely distributed in the forebay of the upstream dam and the average fish density was 0.22 individuals/㎥ under open spillways on 24 June 2010, but when the spillways were closed on 25 June 2010, the fish in the upstream dam dispersed and the average fish density decreased to 0.007 individuals/㎥. Meanwhile, the average fish density in the downstream region was 0.28 individuals/㎥ before the spillway was opened on 24 May 2010, but it decreased to 0.08 individuals/㎥ on 26 June, just after the spillway was closed. The vertical distribution of fish upstream of the dam was not consistent. The target strength (TS) of fish upstream of the dam was larger than that of fish in the downstream region, although the distribution of TS was similar between the upstream and downstream regions. Therefore, we concluded that while numerous fish could swim to the upstream region while the spillways were open, closed spillways obstructed fish migrating upward from the downstream region.

Investigation on Machining Characteristic of Pneumatic Wheel based on Softness Consolidation Abrasives

Xi Zeng,Shi-ming Ji,Ming-sheng Jin,Da-peng Tan,Jue-hui Li,Wen-tao Zeng 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

In order to improve material removal rate of laser hardening workpiece and also make machining tool suitable for free-form surface,a new method based on the softness consolidation abrasives (SCA) is put forward, which means the abrasives are consolidated onthe outer layer of pneumatic wheel to achieve the softness-machining. Binder selecting test shows that acidic silicone is proved tosuit for consolidating particles in cutting process. Combined with robot, the machining system has been established. The machiningeffects of SCA are investigated when it faces with workpiece of different hardness. According to the Preston predicted model, thesimulation results of stress and velocity are proven by analysis of average roughness in the contact region. The contrastive machiningexperimental results show that SCA can supply high cutting stress for material removal and fit for freeform surface’s machining byself-adjustment of flexible body.

Effects of macro-parameters on vibration and radiation noise for high speed wheel gear transmission in electric vehicles

Xi Chen,Chaosheng Song,Caichao Zhu,Jianjun Tan,Najeeb Ullah 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.9

Considering flexible shafts, a coupled dynamic model for the gear transmission system of wheel reducer used in electric vehicle was developed. By combining the acoustics finite element modal for housing in Virtual Lab and the coupled dynamic model for gear transmission system, a simulation method was proposed for the prediction of the radiation noise for the wheel reducer. Then, the effects of different macro geometry gear parameters including pressure angle and helical angle on the dynamic response and radiation noise were investigated under the rated working condition. Results show that the peak-peak value of the transmission error dramatically falls in the starting zone, followed by an upward trend with the increase of the pressure angle for the low speed stage gear pair. The minimum transmission error and vibration acceleration occur when the pressure angle is 17°. The increase of the pressure angle does not affect the sound pressure level at the field point obviously. The design case with 17° pressure angle shows the optimum radiation noise level, which is 4.41dB less than the original model. Compared to the pressure angle, the helix angle has a major influence on the transmission error, vibration acceleration and acoustic radiation noise. With the increase of the helix angle, the time-varying transmission error curve becomes more smooth with a lower peak-peak value. Besides, the increase of helix angle results in lowering the varying and fluctuating trend of both vibration acceleration and acoustic radiation noise. The design case with 24° helix angle shows the prime radiation noise level, which is 7 dB less than the original scheme.

Polydiacetone Acrylamide as Precursors to Polymer Side-Chain Conjugates

Hongzhen Tan,Zhipeng Yu,Junjie Xiao,Xi Wang,Chunwang Yi,Shengpei Su 한국고분자학회 2018 폴리머 Vol.42 No.4

Polydiacetone acrylamide (PDAAM), a reactive polymer containing pendant ketone groups was synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. Kinetic studies indicated a well-controlled behavior of this RAFT polymerization. The characteristics of this RAFT polymerization was also confirmed by a wellcontrolled chain-extending RAFT polymerization using the above-synthesized PDAAM as a macromolecular chain transfer agent. Acid-catalyzed ketalization of PDAAM with trimethylol propane (TMP) was carried out to obtain the polymer containing pendant cyclic ketal groups and hydroxyl groups, PDAAM-TMP. PCL was grafted from PDAAM-TMP by ring-opening polymerization (ROP) in the presence of tin 2-ethylhexanoate as a catalyst to obtain graft copolymer. Basecatalyzed aldol condensation of PDAAM with benzaldehyde was also used to obtain poly[N-(1,1-dimethyl-3-oxo-5-phenyl-pent-4-enyl)-acrylamide] (PDMOPPEAM) having cinnamoyl groups, and the photoreactivity of polymer with cinnamoyl group was studied by UV-visible and IR absorption spectroscopy. Both of these two polymers prepared from PDAAM were characterized by FTIR and 1H NMR spectroscopy. PDAAM can be a multifunctional platform that can undergo further polymerization by ketalization and aldol condensation.

중국 호텔산업 고객들의 전자구전(eWOM)에 미치는 영향 요인에 관한 연구

란희(Luan Xi),단가루(Tan JiaLu),배기형(Ki-Hyung Bae) 한국콘텐츠학회 2023 한국콘텐츠학회논문지 Vol.23 No.1

An Overview of the Genetic Variations of the SARS-CoV-2 Genomes Isolated in Southeast Asian Countries

( Polly Soo Xi Yap ),( Tse Siang Tan ),( Yoke Fun Chan ),( Kok Keng Tee ),( Adeeba Kamarulzaman ),( Cindy Shuan Ju Teh ) 한국미생물 · 생명공학회 2020 Journal of microbiology and biotechnology Vol.30 No.7

Monitoring the mutation dynamics of human severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical in understanding its infectivity, virulence and pathogenicity for development of a vaccine. In an “age of mobility,” the pandemic highlights the importance and vulnerability of regionalization and labor market interdependence in Southeast Asia. We intend to characterize the genetic variability of viral populations within the region to provide preliminary information for regional surveillance in the future. By analyzing 142 complete genomes from South East Asian (SEA) countries, we identified three central variants distinguished by nucleotide and amino acid changes.

Resistance selection with cadmium and changes in the activities of antioxidases in Boettcherisca peregrina (Diptera: Sarcophagidae)

Guo-Xing Wu,Xi Gao,Qing Tan,Zheng-Yue Li,Cui Hu,Gong-yin Ye 한국응용곤충학회 2014 Journal of Asia-Pacific Entomology Vol.17 No.2

In order to establish a physiological link between antioxidases and the resistance level of insects to cadmium(Cd), natural populations of Boettcherisca peregrina (Diptera: Sarcophagidae)weremaintained for 20 generationsand reared either on an uncontaminated diet or on a diet contaminated with cadmium (Cd) at a concentrationequivalent to the median lethal concentration (LC50) as determined every five generations. A relatively susceptiblestrain (S) and a Cd-resistant strain (R) were selected. Themetal accumulation, growth and development, reproduction,and antioxidant enzyme activities in these strains were analyzed. The results showed that R-strain organismshad enhanced juvenile survivorship, increased Cd accumulation, and increased adult female fecundity whencompared with S-strain. The larval enzyme activities of superoxide dismutase (SOD), catalase (CAT), glutathionereductase (GR), and glutathione S-transferase (GST) in R-strain larvae were higher than those in S-strain larvaewhen fed diets with or without Cd. This indicates that Cd resistance in B. peregrina larvae is mediated by SOD,CAT, GR, and GST.

Comparison of volatile components in fresh and dried Zanthoxylum bungeanum Maxim

Wenlin Zhang,Si Tan,Wanpeng Xi,Jianlei Yang,Qinhong Liao,Jianbin Lan,Yukui Lv,Jianmin Tang 한국식품과학회 2019 Food Science and Biotechnology Vol.28 No.4

Fresh and dried Zanthoxylum bungeanumMaxim volatiles of two main cultivars including Dahongpaoand Meihuajiao, were determined through GC–MS andcompared. In all the tested samples, linalool, D-limonene,eucalyptol, 3-nonanone, and b-myrcene were identified asthe five predominant components. The percentages of thesecomponents in fresh Dahongpao were 23.89%, 21.04%,7.46%, 5.63% and 5.87%, respectively. Similar percentages,27.28%, 17.62%, 6.39%, 1.66% and 7.8%, werefound in dried Dahongpao. In general, the contents oflinalool and b-myrcene in dried Dahongpao and Meihuajiaowere slightly higher than those in fresh samples,whereas the contents of D-limonene, eucalyptol, and3-nonanone were lower. Partial least squares discriminantanalysis results showed that the two cultivars could beclearly differentiated based on volatiles, whereas, the freshand dried Zanthoxylum bungeanum Maxim samples couldnot. This demonstrated that the drying process had nosignificant effect on the volatiles.

Markov Chain Modelling Analysis of HIV/AIDS Progression: A Race-based Forecast in the United States

Lee, S.,Ko, J.,Tan, Xi,Patel, Isha,Balkrishnan, R.,Chang, J. Medknow PublicationsMedia Pvt Ltd 2014 Indian journal of pharmaceutical sciences Vol.76 No.2

<P>HIV/AIDS has reached a pandemic level across the world with more than 33 million people who are living with HIV. In the United States, more than half a million people have been victims of AIDS. This study investigates the most vulnerable racial minority population (the African Americans) in the United States and the second least affected (the Caucasians) in order to predict the trends of the epidemic. A Markov chain analysis was used to model the progression of the disease among vulnerable people, infective people and AIDS cases for the two races separately, based on the 2009 Centers of Disease Control and Prevention HIV/AIDS Surveillance Report. Based on the Markov model, our study predicts that the number of African American people living with AIDS diagnosis and HIV infection and dead due to HIV/AIDS will be 662.2, 1225.3 and 62.9 in 2015 and 794.9, 1566.5 and 79.2 in 2030, respectively. The number of Caucasian people living with AIDS diagnosis and HIV infection and dead due to HIV/AIDS will be 96.4, 160 and 6.5 in 2015 and 118.6, 206.9 and 8.3 in 2030, respectively. The numbers of deaths due to HIV/AIDS are quite stable over the years in both the races. There is an increasing trend in the number of people living with HIV infection and AIDS diagnosis in Caucasians compared with African Americans. The absolute number of Caucasians living with AIDS diagnosis and HIV infection is quite smaller compared with African Americans. The results reveal discrepancy in HIV infection, AIDS diagnosis and deaths due to HIV/AIDS among the African Americans and the Caucasians races. There is a need for interventions focusing on HIV/AIDS prevention and management, optimum resource allocation and development of antiAIDS campaigns to reduce the infection rate.</P>

A PORTABLE INTELLIGENT ELECTROCARDIO INSTRUMENT (PIECI)

Li, Ren Xian,Teng, Ji Quan,Tan, Jia Yu,Zhao, Xi Lin 대한전자공학회 1992 HICEC:Harbin International Conference on Electroni Vol.1 No.1

This paper relates to the principle of PIECI controlled by single chip microcomputer. It is widely used in person's life for its portable, small and lower price. It is the result of computer technics combined with experience in clinic. The structure diagrams and some mathematics modes are given in this paper. Also, the software system function, pseudo difference reconizing and processing technics is dis-cussed in the article.