엄西玉林地區域鎭體系發展硏究

張寶秀 서강대학 지역발전연구소 1996 지역발전연구 : 서강전문대 Vol.2 No.-

A city is the political, cultural, and economic centre of the region aroud it. A good urban system of a region can promote the development of the whole region. Yulin Prefecture, in the southeast Guangxi Zhuangzu Autonomous Region, is a richly endowed area. The urban system in Yulin Prefecture has been developing naturally for more than 2000 years, but now its some aspects, such as the centural city's scale, the scale structure, the functional division of the cities and towns, etc., are disadvantageous to the economic development of Yulin Prefecture. So the urban system need to be planned in order to promote effectively the regional overall prosperity. It is what this paper studies. The paper is divided into four sections: Ⅰ. Introduction Ⅱ. The Process of the Urban System Development Ⅲ. The Motive Forces of the Urban System Development Ⅳ. Conclusion - The Planning Developmental Direction of the Urban System Development

Association between Polymorphisms of MSTN and MYF5 Genes and Growth Traits in Three Chinese Cattle Breeds

Zhang, R.F.,Chen, H.,Lei, C.Z.,Zhang, C.L.,Lan, X.Y.,Zhang, Y.D.,Zhang, H.J.,Bao, B.,Niu, H.,Wang, X.Z. Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.12

The objective of this study was to assess the association of polymorphisms in MSTN and MYF5 genes with growth traits in three Chinese cattle breeds. Only one homozygous animal with BB genotype at MSTN locus was observed in Jiaxian population which was at Hardy-Weinberg disequilibrium (p<0.05). The frequencies of allele A at MSTN locus and allele B at MYF5 locus in the three Chinese breeds were 0.9550/0.9730/0.9720 and 0.8275/0.7581/0.7523, respectively. Allele A at MSTN locus and allele B at MYF5 locus were dominant in these three populations. No statistically significant differences in growth traits were observed between the genotypes of the Jiaxian breed at MSTN and MYF5 loci and the Nanyang breed at MYF5 locus. However, there were statistically significant differences between the genotypes at MSTN locus of the Nanyang breed for WH, HG, HGI and HGBLR (p<0.05), and of the Qinchuan breed for BLI (p<0.05). The SNP in MYF5 had significant effects on WH and HHC of Qinchuan animals (p<0.05). These results suggest that MSTN and MYF5 are strong candidate genes that influence growth traits in cattle. Other SNPs of MSTN and MYF5 or other linked genes should also be studied, which could lead to the development of selection plans to improve the performance of Chinese cattle and also promote the breeding of genuine beef cattle in China.

Attenuation of Peripheral Regulatory T-Cell Suppression of Skin-Homing CD8+T Cells in Atopic Dermatitis

Bao-Xiang Zhang,Gang Ding,Jun-Cheng Lyu,Hai-Bo Liu,Dian-Cai Zhang,Dian-Cai Zhang,Xing-Jie Bi,Zhi-Wu Duan 연세대학교의과대학 2015 Yonsei medical journal Vol.56 No.1

Purpose: Cutaneous lymphocyte-associated antigen (CLA)-expressing CD8+T cells have been known to play an important role in the pathogenesis of atopic dermatitis(AD). However, the mechanisms underlying the loss of self-tolerance remainunclear. Regulatory T cells (Tregs) play a key role in the development of homeostasisin the immune system. We, therefore, hypothesized that a reduced ability of Tregs to inhibit autologous CD8+CLA+T cells might be underlying mechanism in AD. Materials and Methods: CD8+CLA+T cells and Tregs were obtained from the peripheral blood of AD patients and control volunteers. The frequenciesof CD8+CLA+T cells were evaluated. The proliferative responses of CD8+CLA+T cells were assessed by flow cytometry, and the levels of transforming growth factor-β1 (TGF-β1) and interleukin-10 (IL-10) in culture supernatants were detected by enzyme-linked immunosorbent assay. Results: Our results revealed higher frequency and increased expression of perforin and granzyme-B in peripheralCD8+CLA+T cells in AD, and lower inhibitory ability of Tregs on proliferation of CD8+CLA+T cells in AD. Meanwhile, the levels of TGF-β1 produced by Tregs were significantly lower in AD, and anti-TGF-β1 abolished such suppression. Conclusion: The attenuated inhibitory ability of Tregs on hyper-activated autologousCD8+CLA+T cells, mediated by TGF-β1, plays an important role in the pathogenesis of AD.

Vibration Reduction for Offshore Platforms via Delayed Sliding Mode H∞ Control

Bao-Lin Zhang,Xiefu Jiang,Qiuxuan Wu,Gong-You Tang 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.1

This paper deals with delayed sliding mode H∞ control for an offshore steel jacket platform subject tononlinear self-excited wave force and external disturbance. By using both current and delayed states, a delayedsliding mode H∞ controller is designed to attenuate vibration of the offshore platform. It is observed throughsimulation results that the delayed sliding mode H∞ controller is capable of reducing the oscillation amplitudesof the offshore platform significantly. Moreover, compared with the delay-free sliding mode H∞ controller, theoscillation amplitudes of the offshore platform under the controllers are almost the same, while the control forcerequired by the delayed sliding mode H∞ controller is less than that by the delay-free sliding mode H∞ controller.

Reduced-order Mapping and Design-oriented Instability for Constant On-time Current-mode Controlled Buck Converters with a PI Compensator

Zhang, Xi,Xu, Jianping,Wu, Jiahui,Bao, Bocheng,Zhou, Guohua,Zhang, Kaitun The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.5

The constant on-time current-mode controlled (COT-CMC) switching dc-dc converter is stable, with no subharmonic oscillation in its current loop when a voltage ripple in its outer voltage loop is ignored. However, when its output capacitance is small or its feedback gain is high, subharmonic oscillation may occur in a COT-CMC buck converter with a proportional-integral (PI) compensator. To investigate the subharmonic instability of COT-CMC buck converters with a PI compensator, an accurate reduced-order asynchronous-switching map model of a COT-CMC buck converter with a PI compensator is established. Based on this, the instability behaviors caused by output capacitance and feedback gain are investigated. Furthermore, an approximate instability condition is obtained and design-oriented stability boundaries in different circuit parameter spaces are yielded. The analysis results show that the instability of COT-CMC buck converters with a PI compensator is mainly affected by the output capacitance, output capacitor equivalent series resistance (ESR), feedback gain, current-sensing gain and constant on-time. The study results of this paper are helpful for the circuit parameter design of COT-CMC switching dc-dc converters. Experimental results are provided to verify the analysis results.

Design-Oriented Stability of Outer Voltage Loop in Capacitor Current Controlled Buck Converters

Zhang, Xi,Zhang, Zhongwei,Bao, Bocheng,Bao, Han,Wu, Zhimin,Yao, Kaiwen,Wu, Jing The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.4

Due to the inherent feedforward of load current, capacitor current (CC) control shows a fast transient response that makes it suitable for the power supplies used in various portable electronic devices. However, considering the effect of the outer voltage loop, the stable range of the duty-cycle is significantly diminished in CC controlled buck converters. To investigate the stability effect of the outer voltage loop on buck converters, a CC controlled buck converter with a proportion-integral (PI) compensator is taken as an example, and its second-order discrete-time model is established. Based on this model, the instability caused by the duty-cycle is discussed with consideration of the outer voltage loop. Then the dynamical effects of the feedback gain of the PI compensator and the equivalent series resistance (ESR) of the output capacitor on the CC controlled buck converter with a PI compensator are studied. Furthermore, the design-oriented closed-loop stability criterion is derived. Finally, PSIM simulations and experimental results are supplied to verify the theoretical analyses.

A Modifi ed Virtual Generator Control for DC Microgrid with Improved Dynamic Characteristics of DC Bus Voltage and Enhanced current Sharing Effect

Zhang Han-Wen,Zhang Qin-Jin,Liu Yan-Cheng,Wang Hong-Lai,Hu Wang-Bao 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.6

Traditional virtual DC motor control can suppress the bus voltage fl uctuations caused by load power mutations and distributed generation fl uctuations. However, the dynamic response is poor and the load current sharing cannot be adjusted. Thus, a modifi ed virtual DC generator control strategy is proposed, which combines the average current controller with the virtual DC generator to enhance current sharing eff ect. The adaptive regulation equations of inertia coeffi cient and damping coeffi cient are elaborated simultaneously to improve the system dynamic characteristics. Then the infl uence of key control parameters on system stability is analyzed by establishing the small signal model. Finally, simulations and a StarSim HIL experimental platform of DC microgrid are built. The results show that the proposed method can eff ectively suppress the DC bus voltage fl uctuations and enable them to have a better dynamic response, while realizing the accurate current sharing.

Optimal design of hydraulic support landing platform for a four-rotor dish-shaped UUV using particle swarm optimization

Zhang, Bao-Shou,Song, Bao-Wei,Jiang, Jun,Mao, Zhao-Yong The Society of Naval Architects of Korea 2016 International Journal of Naval Architecture and Oc Vol.8 No.5

Four-rotor dish-shaped unmanned underwater vehicles (FRDS UUVs) are new type underwater vehicles. The main goal of this paper is to develop a quick method to optimize the design of hydraulic support landing platform for the new UUV. In this paper, the geometry configuration and instability type of the platform are defined. Computational investigations are carried out to study the hydrodynamic performance of the landing platform using the Computational Fluid Dynamics (CFD) method. Then, the response surface model of the optimization objective is established. The intelligent particle swarm optimization (PSO) is applied to finding the optimal solution. The result demonstrates that the stability of landing platform is significantly improved with the global objective index increasing from 1.045 to 1.158 (10.86% higher) after the optimization process.

Optimal design of hydraulic support landing platform for a four-rotor dish-shaped UUV using particle swarm optimization

Bao-Shou Zhang,Baowei Song,Jun Jiang,Zhao-Yong Mao 대한조선학회 2016 International Journal of Naval Architecture and Oc Vol.8 No.5

Four-rotor dish-shaped unmanned underwater vehicles (FRDS UUVs) are new type underwater vehicles. The main goal of this paper is to develop a quick method to optimize the design of hydraulic support landing platform for the new UUV. In this paper, the geometry configuration and instability type of the platform are defined. Computational investigations are carried out to study the hydrodynamic performance of the landing platform using the Computational Fluid Dynamics (CFD) method. Then, the response surface model of the optimization objective is established. The intelligent particle swarm optimization (PSO) is applied to finding the optimal solution. The result demonstrates that the stability of landing platform is significantly improved with the global objective index increasing from 1.045 to 1.158 (10.86% higher) after the optimization process.

Effects of confinement on physiological and psychological responses and expression of interleukin 6 and brain derived neurotrophic factor mRNA in primiparous and multiparous weaning sows

Zhang, Mingyue,Li, Xiang,Li, Jianhong,Sun, Hanqing,Zhang, Xiaohui,Bao, Jun Asian Australasian Association of Animal Productio 2017 Animal Bioscience Vol.30 No.9

Objective: The present study aimed to investigate whether the long-lasting, recurrent restricting of sows leads to the physiological and psychological reaction of discomfort. Methods: Sows (Large White) that had experienced restricting for about 0.5 or 3 years and agematched sows kept in a group housing system (loose sows) were compared. Pupillary light reflex parameters were measured at the weaning stage. Immediately after slaughter, blood samples were taken to measure serum cortisol levels, and the brain was dissected, gene expression in the hippo-campus, frontal cortex and hypothalamus was analyzed. Results: The serum cortisol levels were higher in the confined sows than in the loose sows. The full maturity, but not the young adolescent, confined sows had longer latency time in the onset of pupil constriction than their loose counterparts. Real-time polymerase chain reaction analyses revealed an increased expression of interleukin 6 mRNA in the hippocampus and decreased expression of brain derived neurotrophic factor mRNA in hippocampus and hypothalamus and to a lesser extent in the frontal cortex of the full maturity confined sows, compared with the full maturity loose sows. Conclusion: Taken together, these data indicated that recurrent restricting stress in full maturity sows leads to the physiological and psychological reaction of discomfort.