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Residual stress field of ballised holes
Man On Lai,Zhimin He 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.5
"Ballising, involving pushing a slightly over-sized ball made of hard material through a hole, is a kind of cold working process. Applying ballising process to fastener holes produces compressive residual stress on the edge of the holes, and therefore increases the fatigue life of the components or structures. Quantification of the residual stress field is critical to define and precede the ballising process. In this article, the ballised holes are modeled as cold-expanded holes. Elastic-perfectly plastic theory is employed to analyze the holes with cold expansion process. For theoretical simplification, an axially symmetrical thin plate with a cold expanded hole is assumed. The elasticplastic boundaries and residual stress distribution surrounding the cold expanded hole are derived. With the analysis, the residual stress field can be obtained together with actual cold expansion process in which only the diameters of hole before and after cold expansion need to be measured. As it is a non-destructive method, it provides a convenient way to estimate the elastic-plastic boundaries and residual stresses of cold worked holes. The approach is later extended to the case involving two cold-worked holes. A ballised hole is looked upon as a cold expanded hole and therefore is investigated by the approach. Specimens ballised with different interference levels are investigated. The effects of interference levels and specimen size on residual stresses are studied. The overall residual stresses of plates with two ballised holes are obtained by superposing the residual stresses induced on a single ballised hole. The effects of distance between the centers of the two holes with different interference levels on the residual stress field are revealed."
Nonlinear aerostatic stability analysis of Hutong cable-stayed rail-cum-road bridge
Man Xu,Weiwei Guo,He Xia,Kebing Li 한국풍공학회 2016 Wind and Structures, An International Journal (WAS Vol.23 No.6
To investigate the nonlinear aerostatic stability of the Hutong cable-stayed rail-cum-road bridge with ultra-kilometer main span, a FEM bridge model is established. The tri-component wind loads and geometric nonlinearity are taken into consideration and discussed for the influence of nonlinear parameters and factors on bridge resistant capacity of aerostatic instability. The results show that the effect of initial wind attack-angle is significant for the aerostatic stability analysis of the bridge. The geometric nonlinearities of the bridge are of considerable importance in the analysis, especially the effect of cable sag. The instable mechanism of the Hutong Bridge with a steel truss girder is the spatial combination of vertical bending and torsion with large lateral bending displacement. The design wind velocity is much lower than the static instability wind velocity, and the structural aerostatic resistance capacity can meet the requirement.
Man Zhang,Yanwei Sui,Xiaofang Yuan,Jiqiu Qi,Fuxiang Wei,Qingkun Meng,Yezeng He,Yaojian Ren,Zhi Sun,Jinlong Liu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.3
A nanoflower structure of Zn0.76Co0.24S directly grown on carbon fiber papers (CFP) was successfully designed by a mild two-step hydrothermal method. Benefiting from their fascinating structural features, Zn0.76Co0.24S/CFP electrode exhibits a maximum specific capacitance of 300 F g -1 at current density of 1 A g -1 and 84% capacitance retention after 5,000 cycles at current density of 5 Ag -1. Subsequently, Zn0.76Co0.24S/CFP//AC all-solid-state asymmetric supercapacitor (ASC) device is assembled and able to illuminate the red LEDs. ASC devices deliver a maximum energy density of 9.59 Wh kg -1 at a power density of 750 W kg -1. Therefore, this impressive result demonstrates that the nanoflower Zn0.76Co0.24S have promising applications in the development of high-performance supercapacitors.
Hydrodynamic characters of co-current operation for SO_2 absorption in a laboratory packed column
He Jie,,Tianjin University,Jia Man-Ling,Tan Chang-Bin 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.11
A co-current operation for SO_2 absorption by water was performed in a laboratory-scale packed column. The effects of L/V (liquid-gas ratio) and F (gas phase loading factor) on the SO_2 absorptivity were both investigated. The absorptivity for co-current increased with the increase of L/V and the percentage of absorptivity increase at higher L/V is larger. At lower F, in regular packing there is fluctuation of absorptivity with F increased, but in random packing there is not. With the increase of F, the absorption curve slowed down. It is proposed that in order to obtain a steady desulfurization efficiency, F factor in both kinds of packings should be higher than 4 kg^(0.5)/m^(0.5)s. For absorptivity, which could be reached by both co-current and counter-current, it is suggested that co-current is better because of the higher gas velocity.
Optimal Design of Tall Residential Building with RC Shear Wall and with Rectangular Layout
Jinjie, Men,Qingxuan, Shi,Zhijian, He Council on Tall Building and Urban Habitat Korea 2014 International journal of high-rise buildings Vol.3 No.4
The objective of optimization is to present a design process that minimizes the total material consumption while satisfying current codes and specifications. In the research an optimization formulation for RC shear wall structures is proposed. And based on conceptual design methodology, an optimization process is investigated. Then optimal design techniques and specific explanations are introduced for residential buildings with shear wall structure, especially for that with a rectangular layout. An example of 30-story building is presented to illustrate the effectiveness of the proposed optimal design process. Furthermore, the influence of aspect ratio on the concrete consumption and the steel consumption of the superstructure are analyzed for this typical RC shear wall structure; and their relations are obtained by regressive analysis. Finally, the optimal material consumption is suggested for the residential building with RC shear wall structure and with rectangular layout. The relation and the data suggested can be used for guiding the design of similar RC shear wall structures.
Physical Properties of Polymethylsilsesquioxane with UV-Curable Group for Low-Loss Optical Materials
Lee, He Seung,Choi, Seung-Sock,Lee, Hangseok,Baek, Kyung-Youl,Hong, Soon Man,Lee, Eung Chan,Lee, Jong-Chan,Hwang, Seung Sang Informa UK (TaylorFrancis) 2010 Molecular Crystals and Liquid Crystals Vol.520 No.1
Preparation and In Vitro Release of Ramose Chitosan-Based-5-Fluorouracil Microspheres
Li, He-Ping,Li, Hui,Wang, Zhou-Dong,Zhang, Juan-Juan,Deng, Man-Feng,Chen, San-Long Korean Chemical Society 2013 대한화학회지 Vol.57 No.1
In order to construct a controlled release system of drugs and to reduce toxic side effects of 5-fluorouracil, the novel ramose chitosan-based-5-fluorouracil microspheres (CS-FU-MS) were prepared. Firstly, using chitosan (CS) as carriers and 5-fluorouracil (5-FU) as a model drug, ramose chitosan-based-5-fluorouracil (CS-FU) was efciently synthesized by chemical crosslinking method through microwave irradiation, drug loading was 10.6%; Secondly, CS-FU-MS were prepared by CS-FU self-assembled under the dialysis conditions and the free 5-FU was encapsulated further at the same time. The size dispersivity of particles is uniform, and the average diameter of the CS-FU-MS was $4{\mu}m$. The drug encapsulation efficiency was 76.1%, and the drug loading was increased to 26.22%. CS-FU-MS maintain the zero-order release time in PBS (pH = 7.4) and HCl/KCl (pH = 1.2) dialysis medium was 40h and 34h respectively, and the cumulative release were 58.89% and 79.33% in 182 h. The results showed that CS-FU-MS have excellent sustained release properties.
Nonlinear aerostatic stability analysis of Hutong cable-stayed rail-cum-road bridge
Xu, Man,Guo, Weiwei,Xia, He,Li, Kebing Techno-Press 2016 Wind and Structures, An International Journal (WAS Vol.23 No.6
To investigate the nonlinear aerostatic stability of the Hutong cable-stayed rail-cum-road bridge with ultra-kilometer main span, a FEM bridge model is established. The tri-component wind loads and geometric nonlinearity are taken into consideration and discussed for the influence of nonlinear parameters and factors on bridge resistant capacity of aerostatic instability. The results show that the effect of initial wind attack-angle is significant for the aerostatic stability analysis of the bridge. The geometric nonlinearities of the bridge are of considerable importance in the analysis, especially the effect of cable sag. The instable mechanism of the Hutong Bridge with a steel truss girder is the spatial combination of vertical bending and torsion with large lateral bending displacement. The design wind velocity is much lower than the static instability wind velocity, and the structural aerostatic resistance capacity can meet the requirement.