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Experimental Research on a Hypersonic Configuration with Blunt Forebody Edges
Xiao, Hong,Xu, Zhe-Zhu,Kim, Lae-Sung,Li, Dong-yang,Lyu, Sung-Ki Korean Society for Precision Engineering 2015 International Journal of Precision Engineering and Vol.16 No.10
A design method, for hypersonic forebody configuration with blunt edges, was developed by lift body and waverider. Experimental study was conducted. It was showed that the difference of pressure coefficient, at centre-line and side-line on forebody pre-compression surface, was between 2.5% and 16.7% within the Mach number 5 to 7 and attack angle 0 to 12. These differences were slightly bigger than those of non-blunt-edges forebody. However, experimental data also show that the present configuration can achieve the closed shockwave, and can also realize the automatic overflow of boundary layer on forebody pre-compression surface. It is also observed that the present forebody gets a good aerodynamic performance at high Mach numbers. But with increasing attack angle, the advantage was weakened gradually. And, at the degree of side-slip exceeding 8, the side-line pressure is higher than that of center-line, which indicates that the forebody boundary layer does not achiev automatically overflowing to side surface.
Xiaohong Lu,Haixing Zhang,Zhen-yuan Jia,Yixuan Feng,Steven Y. Liang 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.7
Selection of cutting parameters in micro-milling operations is essential for improving machining efficiency and quality, and prolonging the micro-milling tool life. The increase of material removal rate (MRR) always means the increase of cutting parameters, which may lead to poor surface quality and micro-milling tool failure, even cutter breakage. An optimization approach based on genetic algorithm is used to achieve the maximum MRR under the constraints of surface roughness and cutter breakage. A theoretical model for predicting micro-milling cutter breakage is presented and micro-milling experiments were conducted to establish statistical models of cutter breakage and surface roughness. The optimized results were achieved under the constraints of the specified surface roughness and compared under the different surface roughness limitation. We find that the optimized results improve the machining efficiency and quality in micro-milling and is affected by constraint conditions complicatedly.
A Unified Threat Model for Assessing Threat in Web Applications
Xiaohong Li,Ke He 보안공학연구지원센터 2008 International Journal of Security and Its Applicat Vol.2 No.3
This paper presents a unified threat model for assessing threat in web applications. We extend the threat tree model with more semantic and context information about threat to form the new model which is used to analyze and evaluate threat in the software design stage. We utilize historical statistical information contained in this model to design threat mitigation schemes. The threat assessing results and mitigation schemes can be used to direct secure coding and testing. This makes it possible to design threat-resistant web applications by means of detecting and mitigating threat in the early software design stage.
Prediction model of the surface roughness of micro-milling single crystal copper
Xiaohong Lu,Liang Xue,Feixiang Ruan,Kun Yang,Steven Y. Liang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.11
Presently, the demand for single crystal copper micro-components is increasing in various fields because single crystal copper has good electrical conductivity. Micro-milling technology is an effective processing technology for small single crystal copper parts. Surface roughness is a key performance indicator for micro-milling single crystal copper. Establishing a surface roughness prediction model with high precision is useful to guarantee the processing quality by selecting the cutting parameters for micro-milling. Few studies have currently focused on micro-milling single crystal copper. In this study, the orthogonal experiments of micro-milling single crystal copper were conducted, and the influences of the spindle and feed speeds and axial depth of cut on the surface roughness of micro-milled single crystal copper with different orientations were analyzed by range analyses. The spindle rotation speed was the major affecting factor. The surface roughness of single crystal copper in different crystal orientations was predicted by using the SVM method. Experimental results showed that the average relative error of the surface roughness of <100>, <110>, and <111> crystal orientation single crystal copper was 2.7 %, 3.3 %, and 2.2 %, respectively, and that the maximum relative errors were 7.0 %. 10.1 %, and 3.1 %, respectively. The uncertainty analysis was conducted by using the Monte Carlo method to verify the reliability of the built surface roughness model.
Analysis of South Korea's Direct Investment in China
Xiaohong Zhan Jungseok Research Institute of International Logis 2004 JOURNAL OF INTERNATIONAL LOGISTICS AND TRADE Vol.2 No.2
Using a dynamic perspective this article examines, the general situation of the development of south Korean direct investment in China since 1992, when the two countries established diplomatic relations. It probes many characteristics of South Korean direct investment in China; its late start yet rapid rise; the smaller average value of Korean project investments; the accelerated process of localization by large South Korean enterprises in China; the diversified industrial distribution; and the wide-ranging geographical distribution. It analyses the reasons for the rapid increase in South Korean investment in China: the use of china's low-priced production factors, the direct entry of South Korean enterprises into the Chinese market, and the stable investment environment with fewer labor disputes that China provides. Finally, this article also proves that south Korean enterprises have achieved satisfactory results from their direct investment in China.
Stability and optimal control of microorganisms in continuous culture
Xiaohong Li,Enmin Feng,Zhilong Xiu 한국전산응용수학회 2006 Journal of applied mathematics & informatics Vol.22 No.1-2
The process of producing 1,3-preprandiol by microorganism continuous cultivation would attain its equilibrium state. How to get the highest concentration of 1,3-propanediol at that time is the aim for producers. Based on this fact, an optimization model is introduced in this paper, existence of optimal solution is proved. By infinite-dimensional optimal theory, the optimal condition of model is given and the equivalence between optimal condition and the zero of optimality function is proved.
PCA-BP Based Analysis of the Evaluation of Computerized Accounting Information
Xiaohong Peng 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.8
It is unclear to what extent accounting information can reduce capital risks related to the expected return on a firm’s stock, this is a nonlinear problem; meanwhile, PCA-BP method is suitable for nonlinear problem. This study evaluates accounting information' effect on listed companies' capital cost at Stock Exchange based on PCA-BP method. Results show that implementation of accounting information at listed companies can evaluate the cost of capital by the internal controls, the quality of the financial reports and the process of the company’s transactions. Our finding provides a direct link between the evaluation of a firm's accounting information and its cost of capital.
Xiaohong Cao,Minghui Zhou,Chunling Wang,Lihua Hou,Yuanyuan Li,Linye Chen 한국식품영양과학회 2012 Journal of medicinal food Vol.15 No.2
In this study, Musca domestica pupae lectin (MPL) was screened for its immunomodulatory effect on macrophages. The phagocytosis of macrophages was improved significantly when they were treated with MPL: remarkable changes were observed in the morphology of the cells, the metabolic abilities of DNA and RNA were enhanced, and the production of hepatin was increased. Meanwhile, compared with the control group, not only the mRNA expressions of tumor necrosis factor-a (TNF-a), interleukin-6 (IL-6), and interferon-c (IFN-c) in macrophages, but also the productions of proteins,were strongly induced by MPL; these effects were inhibited by pyrrolidine dithiocarbamate. Further study suggested that MPL could increase the nuclear factor-jB (NF-jB) p65 level in the nucleus. Overall, these results indicate that the improving immunomodulatory activity induced by MPL is mainly due to the increasing productions of TNF-a, IL-6, and IFN-c and that the activation of macrophage by MPL is partly mediated via the NF-jB pathway.