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Zhi-Wen Gao,이강용,You-He Zhou 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.2
In this letter, the shielding or anti-shielding effect is firstly applied to obtain the behavior of two parallel cracks in a two-dimensional type-II superconducting under electromagnetic force. Fracture analysis is performed by the finite element method and the magnetic behavior of superconductor is described by the critical state Bean model. The stress intensity factors at the crack tips can be obtained and discussed for decreasing field after zero-field cooling. The shielding or anti-shielding effect at the crack tips depend on the distance between two parallel cracks and the crack length. The results indicate that the shielding effects of the two parallel cracks increase when the distance between the two parallel cracks decreases. It can be also obtained that the superconductors with shorter cracks has more remarkable shielding effect than those with longer cracks.
Random vibration analysis of train-slab track-bridge coupling system under earthquakes
Zhi-ping Zeng,Xian-feng He,Yan-gang Zhao,Zhi-wu Yu,Ling-kun Chen,Wen-tao Xu,Ping Lou 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.54 No.5
This study aimed to investigate the random vibration characteristic of train-slab track-bridge interaction system subjected to both track irregularities and earthquakes by use of pseudo-excitation method (PEM). Each vehicle subsystem was modeled by multibody dynamics. A three-dimensional rail-slabgirder-pier finite element model was created to simulate slab track and bridge subsystem. The equations of motion for the entire system were established based on the constraint condition of no jump between wheel and rail. The random load vectors of equations of motion were formulated by transforming track irregularities and seismic accelerations into a series of deterministic pseudo-excitations according to their respective power spectral density (PSD) functions by means of PEM. The time-dependent PSDs of random vibration responses of the system were obtained by step-by-step integration method, and the corresponding extreme values were estimated based on the first-passage failure criterion. As a case study, an ICE3 high-speed train passing a fifteen-span simply supported girder bridge simultaneously excited by track irregularities and earthquakes is presented. The evaluated extreme values and the PSD characteristic of the random vibration responses of bridge and train are analyzed, and the influences of train speed and track irregularities (without earthquakes) on the random vibration characteristic of bridge and train are discussed.
Zhi-qiang Li,Dan Gui,Zhi-hua Sun,Jun-bo Zhang,Wen-zhi Zhang,Hui Zhang,Fei Guo,Chuangfu Chen 대한수의학회 2015 Journal of Veterinary Science Vol.16 No.4
Brucellosis is a zoonotic disease that causes animal and human diseases. Vaccination is a major measure for prevention of brucellosis, but it is currently not possible to distinguish vaccinated animals from those that have been naturally infected. Therefore, in this study, we constructed the Brucella (B.) abortus 2380 wbkA mutant (2308DwbkA) and evaluated its virulence. The survival of 2308DwbkA was attenuated in murine macrophage (RAW 264.7) and BALB/c mice, and it induced high protective immunity in mice. The wbkA mutant elicited an anti-Brucella-specific immunoglobulin G response and induced the secretion of gamma interferon. Antibodies to 2308DwbkA could be detected in sera from mice, implying the potential for use of this protein as a diagnostic antigen. The WbkA antigen would allow serological differentiation between infected and vaccinated animals. These results suggest that 2308DwbkA is a potential attenuated vaccine against 16M. This vaccine will be further evaluated in sheep.
Remarkable impact of amino acids on ginsenoside transformation from fresh ginseng to red ginseng
Zhi Liu,Xin Wen,Chong-Zhi Wang,Wei Li,Wei-Hua Huang,Juan Xia,Chang-Chun Ruan,Chun-Su Yuan 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.3
Background: Amino acids are one of the major constituents in Panax ginseng, including neutral aminoacid, acidic amino acid, and basic amino acid. However, whether these amino acids play a role in ginsenosideconversion during the steaming process has not yet been elucidated. Methods: In the present study, to elucidate the role of amino acids in ginsenoside transformation fromfresh ginseng to red ginseng, an amino acids impregnation pretreatment was applied during thesteaming process at 120 C. Acidic glutamic acid and basic arginine were used for the acid impregnationtreatment during the root steaming. The ginsenosides contents, pH, browning intensity, and free aminoacids contents in untreated and amino acidetreated P. ginseng samples were determined. Results: After 2 h of steaming, the concentration of less polar ginsenosides in glutamic acidetreatedP. ginseng was significantly higher than that in untreated P. ginseng during the steaming process. However,the less polar ginsenosides in arginine-treated P. ginseng increased slightly. Meanwhile, free aminoacids contents in fresh P. ginseng, glutamic acid-treated P. ginseng, and arginine-treated P. ginsengsignificantly decreased during steaming from 0 to 2h. The pH also decreased in P. ginseng samples at hightemperatures. The pH decrease in red ginseng was closely related to the decrease in basic amino acidslevels during the steaming process. Conclusion: Amino acids can remarkably affect the acidity of P. ginseng sample by altering the pH value. Theywere the main influential factors for the ginsenoside transformation. These results are useful in elucidatingwhy andhowsteaming induces the structural change of ginsenoside in P. ginseng and also provides an effectiveand green approach to regulate the ginsenoside conversion using amino acids during the steaming process.
The horizontal stability of an FLNG with different turret locations
Zhi-Tian Xie,Jian-Min Yang,Zhi-Qiang Hu,Wen-Hua Zhao,Jing-Rui Zhao 대한조선학회 2015 International Journal of Naval Architecture and Oc Vol.7 No.2
The horizontal stability of a Single-Point Moored (SPM) Floating Liquefied Natural Gas (FLNG) facility is investigated. Both numerical and experimental studies have been conducted for this SPM FLNG. The numerical simulations feature well the experimental data. The effects of the turret locations are studied based on the validated numerical model. Statistic results of the vessel’s motions with different turret locations are conducted and compared. The results show that the longitudinal location of the turret has a significant influence on the horizontal stability, which has a strong relationship with the yaw and roll motions. The calculated top tensions on the hawsers also develop a regular change as changing the turret’s location. The investigation will provide a brief of principles with more details for the design of the ongoing project.
FINITE LOGARITHMIC ORDER SOLUTIONS OF LINEAR q-DIFFERENCE EQUATIONS
Wen, Zhi-Tao Korean Mathematical Society 2014 대한수학회보 Vol.51 No.1
During the last decade, several papers have focused on linear q-difference equations of the form ${\sum}^n_{j=0}a_j(z)f(q^jz)=a_{n+1}(z)$ with entire or meromorphic coefficients. A tool for studying these equations is a q-difference analogue of the lemma on the logarithmic derivative, valid for meromorphic functions of finite logarithmic order ${\rho}_{log}$. It is shown, under certain assumptions, that ${\rho}_{log}(f)$ = max${{\rho}_{log}(a_j)}$ + 1. Moreover, it is illustrated that a q-Casorati determinant plays a similar role in the theory of linear q-difference equations as a Wronskian determinant in the theory of linear differential equations. As a consequence of the main results, it follows that the q-gamma function and the q-exponential functions all have logarithmic order two.
Design of Micro Biopsy Device for Wireless Autonomous Endoscope
Wen-Wen Chen,Guo-Zheng Yan,Hua Liu,Ping-Ping Jiang,Zhi-Wu Wang 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.
Well-established technology that provides assistance from outside the patient may soon give way to alternative approaches that bythe wireless robotic mechanisms inside the patient through natural orifices. For this study, two kinds of micro biopsy mechanisms weredeveloped for capsule endoscope which could traverse the gut environment automatically. This mobility allows the biopsy device tomove to the area of interest to sample specific tissues. Based on the medical and mechanism considerations, we concerned on designprecise biopsy jaw with sufficient cutting force, and the biopsy process should be safe, repeatable and visible. The lead-screw linkagesystem that actuated jaw of biopsy allowing for large force production. Using one micro-motor, the biopsy process was carried outquickly by three motions: stretching to sampling point; bite and cutting off; withdrawing into capsule body with the sample. With thecontrol and vision system, the biopsy process could compete automatically. The robot was capable of traversing in the gut environmentwirelessly and had been successfully used to biopsy gut tissue in vitro. In addition, experimental analysis of the biopsy mechanismshowed good results towards more elaborate tissue manipulation in the future.