The Magnetoresistance in Iron-based Superconductors

B. Lv,R. B. Xie,S. L. Liu,G. J. Wu,H. M. Shao,X. S. Wu 한국자기학회 2011 Journal of Magnetics Vol.16 No.2

The phase transition of vortex matter from solid to liquid was studied in iron-based superconductors. Based on the traditional vortex glass theory, we have examined the magnetoresistivity data of iron-based superconductors using our extended thermal activation model: ρ(B,T) = ρ((T-Tg(B))/(Tc(0)-Tg(B)))<SUP>v(z-1)</SUP>. We predict that the magnetic field-dependent area S + S? which integrates ρ with T is proportional to B<SUP>β</SUP>, where β is the vortex glass transition exponent. From our calculation, the vortex glass transition exponent is 0.33, close to the exponent of area S?+ S is 0.31 in SmO0.9F0.1FeAs; the exponent of area S is 0.63, which is close to the irreversibility line exponent 2/3. Both of the results show the validity of our model. In addition, our model is shown to be effective in describing irreversibility behavior in layered superconductors.

The Magneto Resistance in Iron Based Superconductors and Cuprate Superconductors

B. Lv,R. B. Xie,S. L. Liu,H. M. Shao,X. S. Wu 한국자기학회 2010 한국자기학회 학술연구발표회 논문개요집 Vol.2010 No.12

Optical Nanostructures Fabricated by SU-8 based Nanoimprint Lithography

R. Liu,B.-R. Lu,S.-Q. Xie,J. Wan,Z. Shu,X.-P. Qu,Y. Chen 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.3

The high resolution low-cost and high-volume nano-pattering capability of the nanoimprint lithography (NIL) and the high optical transmittance of SU-8 in the infrared, the visible and the near-UV light ranges have enabled us to apply the SU-8 based NIL to produce various optical nanostructures. We fabricated dielectric and metallic gratings of various groove density (1000 – 5000 lines/mm) in a relatively large area (10 mm × 10 mm) and planar chiral photonic meta-material structure in SU-8 with periods of both 600 nm and 4 μm. We also designed and successfully fabricated distributed Bragg reflectors (DBRs) with Si/SiO2/SU8/air structures Optical measurements of the SU-8 based nanostructures showed good optical performance and interesting properties, and the experimental data agree reasonably well with simulation results. The high resolution low-cost and high-volume nano-pattering capability of the nanoimprint lithography (NIL) and the high optical transmittance of SU-8 in the infrared, the visible and the near-UV light ranges have enabled us to apply the SU-8 based NIL to produce various optical nanostructures. We fabricated dielectric and metallic gratings of various groove density (1000 – 5000 lines/mm) in a relatively large area (10 mm × 10 mm) and planar chiral photonic meta-material structure in SU-8 with periods of both 600 nm and 4 μm. We also designed and successfully fabricated distributed Bragg reflectors (DBRs) with Si/SiO2/SU8/air structures Optical measurements of the SU-8 based nanostructures showed good optical performance and interesting properties, and the experimental data agree reasonably well with simulation results.

RESEARCH ON THE ELECTRO-HYDRAULIC VARIABLE VALVE ACTUATION SYSTEM BASED ON A THREE-WAY PROPORTIONAL REDUCING VALVE

J.-R. LIU,B. JIN,Y.-J. XIE,Y. CHEN,Z.-T. WENG 한국자동차공학회 2009 International journal of automotive technology Vol.10 No.1

As the internal combustion engine moves into the 21st century, fully flexible valve actuation systems are being proposed as an enabling technology for advanced internal combustion engine concepts. Electro-hydraulic valve actuator systems are being considered as a potential variable valve technology. Compared to the servo control system, the system using a proportional valve has the advantages of low price, high anti-pollution ability and high reliability. Our research focuses on exploring the dynamic characteristic of the electro-hydraulic variable valve system, which is based on three-way proportional reducing valve. In this paper, the structure and working principles of the system are described. The dynamic mathematical model of the system is derived. From the analysis of a linearized model and dynamic simulation, it is demonstrated that the system will be stable only if the proportional reducing valve has a positive opening. Some structural factors that affect the system’s dynamic characteristics, such as input signal, the stiffness of the return spring and the pre-tightening force of the return spring, are studied using AMESim. The experimental results coincide with the theoretical and simulated analyses. Further study shows that the dynamic response can be improved effectively by adopting closed-loop control of valve lift. As the internal combustion engine moves into the 21st century, fully flexible valve actuation systems are being proposed as an enabling technology for advanced internal combustion engine concepts. Electro-hydraulic valve actuator systems are being considered as a potential variable valve technology. Compared to the servo control system, the system using a proportional valve has the advantages of low price, high anti-pollution ability and high reliability. Our research focuses on exploring the dynamic characteristic of the electro-hydraulic variable valve system, which is based on three-way proportional reducing valve. In this paper, the structure and working principles of the system are described. The dynamic mathematical model of the system is derived. From the analysis of a linearized model and dynamic simulation, it is demonstrated that the system will be stable only if the proportional reducing valve has a positive opening. Some structural factors that affect the system’s dynamic characteristics, such as input signal, the stiffness of the return spring and the pre-tightening force of the return spring, are studied using AMESim. The experimental results coincide with the theoretical and simulated analyses. Further study shows that the dynamic response can be improved effectively by adopting closed-loop control of valve lift.

Optimized finite element model updating method for damage detection using limited sensor information

Cheng, L.,Xie, H.C.,Spencer, B.F. Jr.,Giles, R.K. Techno-Press 2009 Smart Structures and Systems, An International Jou Vol.5 No.6

Limited, noisy data in vibration testing is a hindrance to the development of structural damage detection. This paper presents a method for optimizing sensor placement and performing damage detection using finite element model updating. Sensitivity analysis of the modal flexibility matrix determines the optimal sensor locations for collecting information on structural damage. The optimal sensor locations require the instrumentation of only a limited number of degrees of freedom. Using noisy modal data from only these limited sensor locations, a method based on model updating and changes in the flexibility matrix successfully determines the location and severity of the imposed damage in numerical simulations. In addition, a steel cantilever beam experiment performed in the laboratory that considered the effects of model error and noise tested the validity of the method. The results show that the proposed approach effectively and robustly detects structural damage using limited, optimal sensor information.

Optimized finite element model updating method for damage detection using limited sensor information

L. Cheng,H. C. Xie,B. F. Spencer, Jr.,R. K. Giles 국제구조공학회 2009 Smart Structures and Systems, An International Jou Vol.5 No.6

Limited, noisy data in vibration testing is a hindrance to the development of structural damage detection. This paper presents a method for optimizing sensor placement and performing damage detection using finite element model updating. Sensitivity analysis of the modal flexibility matrix determines the optimal sensor locations for collecting information on structural damage. The optimal sensor locations require the instrumentation of only a limited number of degrees of freedom. Using noisy modal data from only these limited sensor locations, a method based on model updating and changes in the flexibility matrix successfully determines the location and severity of the imposed damage in numerical simulations. In addition, a steel cantilever beam experiment performed in the laboratory that considered the effects of model error and noise tested the validity of the method. The results show that the proposed approach effectively and robustly detects structural damage using limited, optimal sensor information.

INTEGRATED RIDE AND HANDLING VEHICLE MODEL USING LAGRANGIAN QUASI-COORDINATES

A. F. JAHROMI,R. B. BHAT,W. F. XIE 한국자동차공학회 2015 International journal of automotive technology Vol.16 No.2

In this study, a methodology to build a new integrated ride and handling model is presented based on the Lagrangian method in terms of quasi-coordinates. The governing equations are derived considering the interaction between the ride and handling systems, Euler motion of the frames attached to the wheels and body, the load transfer among the wheels, and the variation of speed in longitudinal direction. The developed model is validated using ADAMS/Car for different maneuvers. In addition, a non-dimensional factor called coupling factor is introduced to study the coupling among different DOFs of the dynamic system. The results of the current study confirm the accuracy of the developed dynamic model for the simulation of the vehicle motion in comparison with the ADAMS/Car simulations and the models available in literature. The coupling factor is confirmed as an indicator parameter to demonstrate the advantages of the developed model over the existing dynamic models.

Cluster Analysis of 12 Chinese Native Chicken Populations Using Microsatellite Markers

Chen, G.H.,Wu, X.S.,Wang, D.Q.,Qin, J.,Wu, S.L.,Zhou, Q.L.,Xie, F.,Cheng, R.,Xu, Q.,Liu, B.,Zhang, X.Y.,Olowofeso, O. Asian Australasian Association of Animal Productio 2004 Animal Bioscience Vol.17 No.8

The genomes of Chinese native chicken populations were screened using microsatellites as molecular markers. A total of, 528 individuals comprisede12 Chinese native chicken populations were typed for 7 microsatellite markers covering 5 linkage groups and genetic variations and genetic distances were also determined. In the 7 microsatellite loci, the number of alleles ranged from 2 to 7 per locus and the mean number of alleles was 4.6 per locus. By using fuzzy cluster, 12 Chinese native chicken populations were divided into three clusters. The first cluster comprised Taihe Silkies, Henan Game Chicken, Langshan Chicken, Dagu Chicken, Xiaoshan Chicken, Beijing Fatty Chicken and Luyuan Chicken. The second cluster included Chahua Chicken, Tibetan Chicken, Xianju Chicken and Baier Chicken. Gushi Chicken formed a separate cluster and demonstrated a long distance when comparing with other chicken populations.

Intramuscular Administration of Zinc Metallothionein to Preslaughter Stressed Pigs Improves Anti-oxidative Status and Pork Quality

Li, L.L.,Hou, Z.P.,Yin, Y.L.,Liu, Y.H.,Hou, D.X.,Zhang, B.,Wu, G.Y.,Kim, S.W.,Fan, M.Z.,Yang, C.B.,Kong, X.F.,Tang, Z.R.,Peng, H.Z.,Deng, D.,Deng, Z.Y.,Xie, M.Y.,Xiong, H.,Kang, P.,Wang, S.X. Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.5

This study was conducted to determine the effects of exogenous zinc-metallothionein (Zn-MT) on anti-oxidative function and pork quality. After feeding a corn-soybean meal-based diet for two weeks, 48 pigs ($Duroc{\times}Landrace{\times}Chinese\;Black Pig$) were assigned randomly to four groups. Pigs in Group 1 were maintained under non-stress conditions, whereas pigs in Groups 2, 3 and 4 were aggressively handled for 25 min to produce stress. Pigs in Groups 1, 2, 3, and 4 received intramuscular administration of saline (control group; CON), 0 (negative control group; NCON), 0.8 (low dose group; LOW), and 1.6 (high dose group; HIGH) mg rabbit liver Zn-MT per kg body weight, respectively. Pigs were slaughtered at 3 and 6 h post-injection. Zn-MT treatment increased (p<0.05) the activities of superoxide dismutase (SOD) and glutathione-peroxidase (GSH-PX) while decreasing the concentration of malondialdehyde (MDA) in liver. These responses were greater (p<0.05) at 6 h than at 3 h post Zn-MT injection. Zn-MT treatment increased (p<0.05) hepatic SOD mRNA levels in a time and dose-dependent manner and decreased (p<0.05) serum glutamate-pyruvate transaminase and lactate dehydrogenase activities (indicators of tissue integrity). Zn-MT administration decreased (p<0.05) lactate concentration and increased (p<0.05) pH and water-holding capacity in the longissimus thorasis meat. Collectively, our results indicate that intramuscular administration of Zn-MT to pre-slaughter stressed pigs improved tissue anti-oxidative ability and meat quality.