The Biotypes, Wing-forms and the Immigration of Brown Planthopper, Nilaparvata lugens Stal, in Zhejiang Province, China

Yu, Xiaoping,Lu, Zhongxian,Wu, Guorui,Tao, Linyong,Chen, Jianming,Zheng, Xusong,Xu, Hongxing Korean Society of Applied Entomology 2001 Journal of Asia-Pacific Entomology Vol.4 No.2

The virulence change (biotype), wing form development and immigration of brown planthopper (BPH) Nilaparvata lugens Stal, population in Zhejiang province was studied as compared to these BPH populations collected from Guangxi and Yunnan province, China and Philippines. The results indicate that the Zhejiang population could successfully infest variety IR26 and Mudgo after 1989, and ASD7 and IR36 after 1998, showing the characters of BPH biotype 2 and biotypes 3. The BPH tropical populations such as Guangxi population, however, adapted the resistant varieties IR26, Mudgo and ASD7 earlier. In 1997, the nymphal survival indices of Guangxi and Yunnan populations on Rathu Heenati (Bph3) were up to 70.9 and 66.7 respectively, higher than Zhejiang population. The Zhejiang populations show low brachupterous rates and have a negative correlation with nymphal density, belonging to the temperate type. The Philippine populations are almost brachypterous, however, the brachypterous rates of BPH males raise with the increase of nymphal density. The Guangxi population has a high brachypterous rate, being similar to the tropical type. On the other hand, tests showed that the lowest survival rate, longer duration of nymphs and the lightest weight of brachypterous female occurred in the $2^{nd}$ generation of BPH after continuously feeding on resistant variety. Physiologically, the highest activities of superoxide dismutase (SOD) and catalase (CAT) were detected in the second generation of the BPH feeding on resistant rice variety.

Morphological Characteristics of the Ice Margins of Antarctic Ice Shelf and Outlet Glacier Extracted from ICESat Laser Altimetry Along-Track Profiles

Kim, Jieun,Yu, Jaehyung,Wang, Lei,Liu, Hongxing,Shin, Haein Chinese Geoscience Union 2016 TAO Vol.27 No.4

<P>The Antarctic ice sheet topography including elevation and slope is a key parameter for understanding ice sheet dynamics because the surface slope is a major controller of the ice flow gravitational driving stress magnitude. This study used Ice, Cloud, and land Elevation Satellite (ICES at) laser altimetry data to analyze the ice margin morphological parameters for 20 ice shelves and 12 outlet glaciers distributed over Antarctica. The bottom-up segmentation algorithm application effectively extracted the morphological parameters from the laser altimetry profiles. The ice shelves had an average boundary elevation of 29.5 m and a slope of 7.8 degrees, with a decreasing surface slope pattern from the boundary to the inner side. The average number of segments and the length of the coastal margin for ice shelves extracted from the bottom-up segmentation algorithm is 3.2 and is 18.4 km, respectively. The outlet glaciers had a boundary elevation of 29.7 m with a slope of 7.4 degrees. The average number of segments for outlet glaciers is 5.03, and the distance to the margin is 10.38 km. The outlet glaciers were of two types. The first type had a higher ice margin slope, a shorter ice margin distance and concave shape to the surface profile. The second type had a much shorter ice margin distance and an undulating surface profile shape. The ice margin morphology shows distinctive characteristics depending on the major ice loss process.</P>

Transverse impact characteristics of a rubber pipe expansion joint

Yong Chen,Wang Yu,ZhiYi Zhang,Hongxing Hua 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.6

The transverse impact characteristics of a rubber pipe expansion joint are studied. A pair of joints assembled end to end with an inserted middle mass is tested on a drop shock testing machine. Based on the test results, an equivalent fixed-fixed beam model with polynomial stiffness and damping is applied to predict the transverse impact response and identify the nonlinear impact parameters. The least square residual between the computed and test results is defined to drive the identification optimization. The response surface methodology in combination with the generalized reduced gradient method is used to search the best matching coefficients. Final results show that the equivalent bending stiffness of the tested rubber expansion joint gradually decreases with the transverse deformation and is greatly influenced by its internal working pressure.

Coupled irradiation-thermal-mechanical analysis of the solid-state core in a heat pipe cooled reactor

Yugao Ma,Jiusong Liu,Hongxing Yu,Changqing Tian,Shanfang Huang,Jian Deng,Xiaoming Chai,Yu Liu,Xiaoqiang He 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.6

The solid-state core of a heat pipe cooled reactor operates at high temperatures over 1000 K withthermal and irradiation-induced expansion during burnup. The expansion changes the gap thicknessbetween the solid components and the material properties, and may even cause the gap closure, whichthen significantly influences the thermal and mechanical characteristics of the reactor core. This studydeveloped an irradiation behavior model for HPRTRAN, a heat pipe reactor system analysis code, tointroduce the irradiation effects such as swelling and creep. The megawatt heat pipe reactor MegaPowerwas chosen as an application case. The coupled irradiation-thermal-mechanical model was developed tosimulate the irradiation effects on the heat transfer and stresses of the whole reactor core. The resultsshow that the irradiation deformation effect is significant, with the irradiation-induced strains up to2.82% for fuel and 0.30% for monolith at the end of the reactor lifetime. The peak temperatures during thelifetime are 1027:3 K for the fuel and 956:2 K for monolith. The gap closure enhances the heat transferbut caused high stresses exceeding the yield strength in the monolith

Thermal-fluid-structure coupling analysis for plate-type fuel assembly under irradiation. Part-I numerical methodology

Li, Yuanming,Yuan, Pan,Ren, Quan-yao,Su, Guanghui,Yu, Hongxing,Wang, Haoyu,Zheng, Meiyin,Wu, Yingwei,Ding, Shurong Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.5

The plate-type fuel assembly adopted in nuclear research reactor suffers from complicated effect induced by non-uniform irradiation, which might affect its stress conditions, mechanical behavior and thermal-hydraulic performance. A reliable numerical method is of great importance to reveal the complex evolution of mechanical deformation, flow redistribution and temperature field for the plate-type fuel assembly under non-uniform irradiation. This paper is the first part of a two-part study developing the numerical methodology for the thermal-fluid-structure coupling behaviors of plate-type fuel assembly under irradiation. In this paper, the thermal-fluid-structure coupling methodology has been developed for plate-type fuel assembly under non-uniform irradiation condition by exchanging thermal-hydraulic and mechanical deformation parameters between Finite Element Model (FEM) software and Computational Fluid Dynamic (CFD) software with Mesh-based parallel Code Coupling Interface (MpCCI), which has been validated with experimental results. Based on the established methodology, the effects of non-uniform irradiation and fluid were discussed, which demonstrated that the maximum mechanical deformation with irradiation was dozens of times larger than that without irradiation and the hydraulic load on fuel plates due to differential pressure played a dominant role in the mechanical deformation.

Thermal-fluid-structure coupling analysis on plate-type fuel assembly under irradiation. Part-II Mechanical deformation and thermal-hydraulic characteristics

Li, Yuanming,Ren, Quan-yao,Yuan, Pan,Su, Guanghui,Yu, Hongxing,Zheng, Meiyin,Wang, Haoyu,Wu, Yingwei,Ding, Shurong Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.5

The plate-type fuel assembly adopted in nuclear research reactor suffers from complicated effect induced by non-uniform irradiation, which might affect stress conditions, mechanical behaviors and thermal-hydraulic performance of the fuel assembly. This paper is the Part II work of a two-part study devoted to analyzing the complex unique mechanical deformation and thermal-hydraulic characteristics for the typical plate-type fuel assembly under irradiation effect, which is on the basis of developed and verified numerical thermal-fluid-structure coupling methodology under irradiation in Part I of this work. The mechanical deformation, thermal-hydraulic performance and Mises stress have been analyzed for the typical plate-type fuel assembly consisting of support plates under non-uniform irradiation. It was interesting to observe that: the plate-type fuel assembly including the fuel plates and support plates tended to bend towards the location with maximum fission rate; the hot spots in the fuel foil appeared at the location with maximum thickness increment; the maximum Mises stress of fuel foil was located at the adjacent location with the maximum plate thickness increment et al.