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Antibiotic residues from aquaculture farms and their ecological risks in Southeast Asia:a case study from Malaysia

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Ecosystem Health and Sustainability 2021年第1期7卷 300-317页

作者： Ee Lean Thiang choon weng lee Hideshige Takada Kanako Seki Ayaka Takei Satoru Suzuki Aijun Wang Chui Wei Bong Institute of Ocean and Earth Sciences University MalayaKuala LumpurMalaysia Institute for Advanced Studies University MalayaKuala LumpurMalaysia Institute of Biological Sciences University MalayaKuala LumpurMalaysia Laboratory of Organic Geochemistry Tokyo University of Agriculture and TechnologyFuchuTokyoJapan Center for Marine Environmental Studies Ehime UniversityMatsuyamaEhimeJapan Third Institute of Oceanography State Oceanic AdministrationXiamenChina

Background and Objectives:One major source of antibiotic contamination in the sea is from *** monitored the concentration of commonly used antibiotic classes and antibiotic resistance genes(tet(M),sul1,sul2 and sul3)in aquaculture farms in Peninsular ***:Antibiotic residues and resistance genes were quantified using high-performance liquid chromatography and real-time PCR *** quotients in European technical guidance document on risk assessment was used to assess the potential environmental ***:We detected 23 antibiotics with tetracyclines,sulfonamides and quinolones were the most frequently detected classes,indicating a wide distribution of antibiotics in Malaysian aquaculture *** dendrogram and heatmap revealed three groups of antibiotic concentration patterns but with no differences in the types of antibiotics usage among aquaculture *** ARGs(10^(−3)copies/16S)were detected in>90%of the sites except for ***,enrofloxacin,norfloxacin and lincomycin posed risks to cyanobacteria and algae in Kelantan,Perak and ***:Relative to Asian aquaculture farms,the residues detected here were at low or moderate levels except for *** study will be useful to develop effective management of aquaculture wastewater in order to mitigate antibiotic pollution and transmission of ARGs to humans through the food chain.

关键词： Antibiotic residues resistance genes risk assessment aquaculture

Compact ultrafast neutron sources via bulk acceleration of deuteron ions in an optical trap

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Matter and Radiation at Extremes 2024年第5期9卷 22-31页

作者： Zhiyu Lei Hanghang Ma Xiaobo Zhang Lin Yu Yihang Zhang Yutong Li Suming weng Min Chen Jie Zhang Zhengming Sheng Key Laboratory for Laser Plasmas and School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Centre of IFSA Shanghai Jiao Tong UniversityShanghai 200240China Tsung-Dao lee Institute Shanghai Jiao Tong UniversityShanghai 201210China College of Physics and Electronics Engineering Northwest Normal UniversityLanzhou 730070China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China

A scheme for a quasi-monoenergetic high-flux neutron source with femtosecond duration and highly anisotropic angular distribution is *** scheme is based on bulk acceleration of deuteron ions in an optical trap or density grating formed by two counter-propagating laser pulses at an intensity of-10^(16)W~cm^(2)in a near-critical-density *** deuterons are first pre-accelerated to an energy of tens of keV in the ambipolar fields formed in the optical *** energy is boosted to the MeV level by another one or two laser pulses at an intensity of-10^(20)W~cm^(2),enabling fusion reactions to be triggered with high *** contrast to previously proposed pitcher–catcher configurations,our scheme can provide spatially periodic acceleration structures and effective collisions between deuterons inside the whole target ***,neutrons are generated directly inside the optical *** simulations show that neutron pulses with energy 2–8 MeV,yield 10^(18)–10^(19)n/s,and total number 106–107 in a duration-400 fs can be obtained with a 25μm ***,the neutron pulses exhibit unique angularly dependent energy spectra and flux distributions,predominantly along the axis of the energy-boosting *** microsize femtosecond neutron pulses may find many applications,such as high-resolution fast neutron imaging and nuclear physics research.

关键词： acceleration scheme angular

Fast efficient photon deceleration in plasmas by using two laser pulses at different frequencies

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Matter and Radiation at Extremes 2024年第3期9卷 11-18页

作者： Y.X.Wang X.L.Zhu S.M.weng P.Li X.F.Li H.Ai H.R.Pan Z.M.Sheng Key Laboratory for Laser Plasmas(moe) School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center of IFSA Shanghai Jiao Tong UniversityShanghai 200240China Research Center of Laser Fusion of China Academy of Engineering Physics MianyangSichuan 621900China State key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Tsung-dao lee Institute Shanghai Jiao Tong UniversityShanghai 200240China

The generation of ultrashort high-power light sources in the mid-infrared(mid-IR)to terahertz(THz)range is of interest for applications in a number of fields,from fundamental research to biology and *** conventional laser technology,photon deceleration in plasma wakes provides an alternative approach to the generation of ultrashort mid-IR or THz ***,we present a photon deceleration scheme for the efficient generation of ultrashort mid-IR or THz pulses by using an intense driver laser pulse with a relatively short wavelength and a signal laser pulse with a relatively long *** signal pulse trails the driver pulse with an appropriate time delay such that it sits at the front of the second wake bubble that is driven by the driver *** to its relatively long wavelength,the signal pulse will be subjected to a large gradient of the refractive index in the plasma wake ***,the photon deceleration in the plasma wake becomes faster and more efficient for signal pulses with longer *** greatly enhances the capacity and efficiency of photon deceleration in the generation of ultrashort high-power light sources in the long-wavelength IR and THz spectral ranges.

关键词： laser ultrashort photon

Development of analysis model for geometric error in turning processes

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Journal of Central South University 2011年第3期18卷 711-717页

作者： lee Mun-jae lee choon-man Department of Mechanical Design and Manufacturing Engineering Changwon National University

A finite element model was established for analyzing the geometric errors in turning operations and a two-step analyzing process was proposed. In the first analyzing step, the cutting force and the cutting heat for the cutting conditions were obtained using the AdvantEdge. Also, the deformation of a workpiece was estimated in the second step using the ANSYS. The deformation was analyzed for a 150 mm-long workpiece at three different measuring points, such as 10, 70 and 130 mm from a reference point, and the amounts of the deformation were compared through experiments. /n the results of the comparison and analysis, the values obtained from these comparison and analysis represent similar tendencies. Also, it is verified that their geometric errors increase with the increase in temperature. In addition, regarding the factors that affect the deformation of a workpiecc, it can be seen that the geometric error in the lathe is about 15%, the error caused by the cutting force is about 10%, and the deformation caused by the heat is about 75%.

关键词： geometric error machining accuracy finite element analysis turning cutting force, cutting temperature

Development of a one-axis manipulator for laser-assisted machining

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Journal of Central South University 2013年第2期20卷 378-384页

作者： KIM Dong-hyeon lee choon-man Department of Mechanical Design & Manufacturing Engineering Changwon National University

Laser-assisted machining has been considered as a new alternative machining method of difficult-to-cut materials. A laser module with one-axis manipulator is developed to focus on preheating laser beam effectively. First of all, the thermal characteristic analysis was performed to verify the importance of laser module location. Laser module should be moved within 1 mm. Analysis conditions of three positions in driving range of the one-axis manipulator are selected. And a C coupling is used as a connection device for spindle and laser module. An initial model has one C coupling, and the number of C coupling has been increased from 1 to 2 in an improved model. And the analysis is carried out again for the one-axis manipulator. The results of the static analysis, the maximum displacement and the maximum stress are decreased by 22% and 11%, respectively, for the improved model when the laser module is located at farthest away from the spindle unit. As a result of the modal analysis, the first natural frequency mode is increased by 13%, 18% and 12% at these positions of the improved model, respectively. The harmonic analysis of the improved model was performed by analyzing the results of the modal analysis. The maximum deformation was 0.33 mm in driving unit at 222 Hz. And the maximum compliance of the ISO axis direction was 0.23 mm/N. Finally, the one-axis manipulator has been fabricated successfully using the analysis result.

关键词： finite element analysis (FEA) laser-assisted machining manipulator

Development of two-axis control index table driven by direct drive motors

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Journal of Central South University 2011年第6期18卷 1962-1968页

作者： KIM Jae-hyun lee choon-man School of Mechatronics Changwon National University

The stability and reliability of a tilting index table should be considered at the design stage. A design method for the lightweight and improvement of the stability of the structure in a tilting index table was proposed using a commercial analysis program, ANSYS Workbench 12, by analyzing the static-thermal characteristics of the developed high-accuracy tilting index table at its design stage. The results of the performed structural analysis show that the maximum stress is generated at the stock tail part. An optimum design for the stock tail part was carried out to reduce the maximum stress and deformation. Also, the design variables were determined by considering the support of the stock tail part for the C-axis body. In the comparison of the results before and after the optimization, the maximum deformation and stress are improved by 2.8% and 8%, respectively.

关键词： tilting index table structural analysis modal analysis thermal analysis optimum design

Cloning,expression in Escherichia coli,and enzymatic properties of laccase from Aeromonas hydrophila WL-11

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Journal of Environmental Sciences 2010年第4期22卷 635-640页

作者： Jing Wu Kyoung-Sook Kim Jai-Heon lee Young-choon lee Department of Biotechnology Dong-A University Busan 604-714 South Korea. Brain Korea 21 Center for Silver-Bio Industrialization Dong-A University Busan 604-714 South Korea

A strain WL-11 with high laccase activity was isolated from activated sludge collected from the effluent treatment plant of a textile and dyeing industry. It was identified as Aeromonas hydrophila by physiological test and 16S rDNA sequence analysis. A gene encoding of laccase from a newly isolated Aeromonas hydrophila WL-11 was cloned and characterized. Nucleotide sequence analysis showed an open reading frame of 1605 bp encoding a polypeptide comprised of 534 amino acids. The primary structure of the enzyme predicted the structural features characteristic of other laccases, including the conserved regions of four histidine-rich copper-binding sites. The predicted amino acid sequence showed a high homology （more than 60%） with bacterial laccases in the genome and protein databases and the highest degree of similarity （61% identity） was observed with the multicopper oxidase of KlebsieUa sp. 601. When expressed in Escherichia coli, the recombinant enzyme was overproduced in the cytoplasm as soluble and active form. The purified enzyme had an optimum pH of 2.6 and 8.0 for ABTS （2,2＇-azino-bis（3-ethylbenzthiazolinesulfonic acid） and DMP （2,6-dimethoxyphenol）, respectively. The kinetic study on ABTS revealed a higher affinity of this enzyme to this substrate than DMP.

关键词： cloning expression enzymatic properties laccase Aeromonas hydrophila

Multi-stage optimum design of magazine type automatic tool changer arm

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Journal of Central South University 2012年第1期19卷 174-178页

作者： KIM Jae-Hyun lee choon-Man School of Mechatronics Changwon National UniversityChangwon 641-773Korea

To enhance machining efficiency,tool change time has to be ***,for an automatic tool changer attached to a machining center,the tool change time is to be *** the automatic tool changer is a main part of the machining center as a driving *** static attributes of the automatic tool changer using the commercial code,ANSYS Workbench V12,were tried to *** the optimum design of automatic tool changer arm was proposed by performing the multi-stage optimum *** shape optimization of the automatic tool changer was proposed and the result was verified to obtain acceptable *** is possible to obtain an optimized model in which the maximum deformation,maximum stress,and mass are reduced by 10.46%,12.89% and 9.26%,respectively,compared with those of the initial ***,the results between conventional method by the design of experiments and proposed method by the multi-stage optimum design method were compared.

关键词： automatic tool changer optimum design structural analysis exchange arm

Effects of automatic variable preload device on performance of spindle

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Journal of Central South University 2012年第1期19卷 150-154页

作者： KIM Dong-Hyeon lee choon-Man Department of Mechanical Design and Manufacturing Engineering Changwon National UniversityChangwon 641-773Korea

To increase the machine accuracy by improving the stiffness of bearings,a preload was applied to bearings.A variable preload technology was necessary to perform machining processes in both low and high speed *** automatic variable preload device was fabricated using an eccentric *** installing the fabricated device on a spindle,the effect of the automatic variable preload device on the performance of the spindle was *** the results of the vibration measurement of the spindle,the vibration is increased by 20%-37% according to measurement points at the maximum rotation speed of 5 000 r/***,in the results of the noise measurement of the spindle,the spindle rotation speed is increased by about 1.9% and 1.5% at the front and side of the spindle,*** on the results of this analysis,an improved method that reduces such effects on the performance of the spindle is proposed.

关键词： machine tool spindle automatic variable preload device vibration noise