http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Jiabing Zhang (검색결과 5 건)
- 무료
- 기관 내 무료
- 유료
-
-
Meiqing Zhang,Xiaoming Yuan,Jiabing Hu 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
Voltage-source converter (VSC) high voltage direct current (HVDC) connected to islanded grid is becoming a normal system operation mode. However, there is little research on the stability analysis of VSC-HVDC connected to islanded grid. On the basis of previous work, this paper analyzes the stability and adaptability of PLL-synchronized VSC-HVDC adopted with the additional frequency regulation scheme (FRS) under islanded grid. By defining the instantaneous frequency and regarding it as a state variable, the small-signal model of PLL-synchronized VSC under both grid-islanded mode and grid-connected mode is synthetically established. On this basis, the impact of FRS on the stability of PLL-synchronized VSC under islanded grid is analyzed, and then the adaptability of FRS to different grid strengths is investigated via considering different short current ratios (SCRs), including islanded grid (SCR=0), weak grid (SCR<2) and strong grid (SCR>5). The analysis results show that the FRS has important role on enhancing the small signal stability of the islanded grid, and also has excellent adaptability to the wide change of grid conditions, so as to further improve the possibility of the FRS applied in practical projects. These results finally are verified by time-domain simulations.
-
The collapse deformation control of granite residual soil in tunnel surrounding rock: A case study
Zhen Huang,Juncai Huang,Jiabing Zhang,Xuesong Li,Huanyu Zheng,Xiaofei Liu 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.5
Since it is difficult to control tunnel construction in weak and broken surrounding rock, the large deformation of tunnel surrounding rock has always been a great danger to construction safety. In this study, the characteristics of a tunnel collapse deformation and its causal factors are analysed as an example of a large deformation accident in a tunnel with granite residual soil in the surrounding rock. First, a support vector regression algorithm optimized by the genetic annealing algorithm (GASA-SVR) is used to construct a back-analysis model of the surrounding rock mechanical parameters. Then, based on the field measured data, the surrounding rock mechanical parameters of the tunnel are inverted. Finally, the finite element method is used to simulate different surrounding rock deformation control schemes, and the optimal deformation control measures are obtained. The results show that the simulated annealing algorithm (SA) enhances the local search capability of the genetic algorithm (GA) so that the hyperparameter optimization solution of the support vector regression (SVR) is the global optimal solution. The parameters obtained from the inversion of the GASA-SVR model are simulated in PLAXIS3D within 4.0% of the measured values in the field. With the application of optimized support measures at the site, the deformation of the surrounding rock has been effectively controlled.
-
Shuancang Yu,Xiaoyi Wang,Xiuyun Zhao,Deshuang Zhang,Yangjun Yu,Jiabing Xu,Fenglan Zhang 한국유전학회 2010 Genes & Genomics Vol.32 No.5
Pak‐choi (Brassica rapa L. ssp. chinensis Makino) is one of the most important vegetable, especially in southern China. Morphological traits of Pak‐choi vary widely, and the genetic basis of these variations is largely undescribed. In this study,we evaluated eighty Pak‐choi accessions for genetic diversity based on 29 morphological descriptors and 20 microsatellite (SSR) loci. Our data reveal a high level of diversity in this set of Pak‐choi accessions. Euclidean distance was used for cluster analysis. The UPGMA dendrogram grouped the Pakchoi accessions into five major clusters based on morphological characteristics. As expected, similar morphological characteristics grouped together in cluster branches. Further,population structure was explored to identify subpopulations based on allele frequency. Five groups were identified, and showed considerable correlation with the morphological clusters. Associations between SSR markers and agronomic traits were further investigated using a non‐parametric Kruskal–Wallis K‐test and six additional parametric models. Significant associations were found between 18 SSR loci and 28 morphological traits. This study provides evidence that marker‐trait associations can be validated in segregating populations and exploited through marker‐assisted selection.
-
Shaokun Ma,Haijun Huang,Fapai Tian,Jian Gong,Jiabing Zhang,Zhibo Duan 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.5
In this study, the effects of relative density and confining pressure on the shear characteristics of round gravel are investigated using a large-scale triaxial apparatus and the discrete element method. A simple and efficient numerical method for simulating flexible membranes is introduced. The results show that the stress-strain curves develop from hardened to softened type with increasing relative density, while the stress-strain curves develop from softened to hardened type with increasing confining pressure. As the axial strain increases, the strong contact force chains are vertically distributed, and the larger the relative density and confining pressure, the greater the number and thickness of the strong contact force chains. In the shear process, the distribution of average normal and tangential contact forces show “peanut-shaped” and “petal-shaped”, respectively. The increase in relative density increases the anisotropy of the specimen, while the increase in confining pressure results in a decrease. A linear relationship exists between the macroscopic stress ratio and the anisotropy coefficient. The anisotropy coefficient of the normal contact force provides the greatest contribution to the macroscopic shear strength (about 55%), followed by the anisotropy coefficient of the contact normal (about 26%) and that of the tangential contact force (about 19%).
스콜라연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
