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Atomistic simulation and investigation of nanoindentation, contact pressure and nanohardness

  • Chen, Chuin-Shan;Wang, Chien-Kai;Chang, Shu-Wei
    • Interaction and multiscale mechanics
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    • v.1 no.4
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    • pp.411-422
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    • 2008
  • Atomistic simulation of nanoindentation with spherical indenters was carried out to study dislocation structures, mean contact pressure, and nanohardness of Au and Al thin films. Slip vectors and atomic stresses were used to characterize the dislocation processes. Two different characteristics were found in the induced dislocation structures: wide-spread slip activities in Al, and confined and intact structures in Au. For both samples, the mean contact pressure varied significantly during the early stages of indentation but reached a steady value soon after the first apparent load drop. This indicates that the nanohardness of Al and Au is not affected by the indentation depth for spherical indenters, even at the atomistic scale.

Experimental Study on Adjustment of Inlet Nozzle Section to Flow Rate Variation for Darrieus-type Hydro-Turbine

  • Watanabe, Satoshi;Shimokawa, Kai;Furukawa, Akinori;Okuma, Kusuo;Matsushita, Daisuke
    • International Journal of Fluid Machinery and Systems
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    • v.5 no.1
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    • pp.30-37
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    • 2012
  • A two dimensional Darrieus-type turbine has been proposed for the hydropower utilization of extra-low head less than 2m. In a practical use of Darrieus-type hydro-turbine, head and flow rate may be varied temporally and seasonally. Considering that the cost advantage is required for the low head hydro turbine system, the Darrieus turbine should be operated with high efficiency in the wider range of flow rate possibly by using an additional device with simpler mechanism. In the present paper, an adjustment of inlet nozzle section by lowering the inlet nozzle height is proposed to obtain the preferable inlet velocity in low flow rate conditions. Effects of resulting spanwise partial inlet flow are investigated. Finally, an effective modification of inlet nozzle height over flow rate variation is shown.

AN ITERATIVE ALGORITHM FOR SOLVING THE LEAST-SQUARES PROBLEM OF MATRIX EQUATION AXB+CYD=E

  • Shen, Kai-Juan;You, Chuan-Hua;Du, Yu-Xia
    • Journal of applied mathematics & informatics
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    • v.26 no.5_6
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    • pp.1233-1245
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    • 2008
  • In this paper, an iterative method is proposed to solve the least-squares problem of matrix equation AXB+CYD=E over unknown matrix pair [X, Y]. By this iterative method, for any initial matrix pair [$X_1,\;Y_1$], a solution pair or the least-norm least-squares solution pair of which can be obtained within finite iterative steps in the absence of roundoff errors. In addition, we also consider the optimal approximation problem for the given matrix pair [$X_0,\;Y_0$] in Frobenius norm. Given numerical examples show that the algorithm is efficient.

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Intentions of Employees to Whistleblow Information Security Policy Violations in the Organization

  • Wei, Liang-Cheng;Hsu, Carol;Wang, Kai
    • Asia pacific journal of information systems
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    • v.26 no.1
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    • pp.163-188
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    • 2016
  • Compliance with information security policies has been an important managerial concern in organizations. Unlike traditional general deterrent theory, this study proposes whistle-blowing as an alternative approach for reducing internal information security policy violations. We build on the theories of planned behavior and rational choice as well as develop a theoretical model to understand the factors that influence whistle-blowing attitudes and intention at both the organizational and individual levels. Our empirical results reveal that altruistic and egoistic concerns are involved in the development of whistle-blowing attitudes. The results not only extend our understanding of whistle-blowing motivation but also offer directions to managers in promoting internal disclosure of information security breaches.

RSA vs DEM in view of particle packing-related properties of cementitious materials

  • Li, Kai;Stroeven, Piet
    • Computers and Concrete
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    • v.22 no.1
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    • pp.83-91
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    • 2018
  • Various systems for simulating particulate matter are developed and used in concrete technology for producing virtual cementitious materials on the different levels of the microstructure. Basically, the systems can be classified as two distinct families, namely random sequential addition systems (RSAs) and discrete element methods (DEMs). The first type is hardly being used for this purpose outside concrete technology, but became popular among concrete technologists. Hence, it is of utmost relevance to compare the two families in their capabilities, so that the reliability of produced data can be estimated. This paper pursues to do this on the basis of earlier published material of work performed by a succession of PhD students in the group of the second author. Limited references will be given to external sources.

Investigation on Terahertz Generation by GaP Ridge Waveguide Based on Cascaded Difference Frequency Generation

  • Li, Zhongyang;Zhong, Kai;Bing, Pibin;Yuan, Sheng;Xu, Degang;Yao, Jianquan
    • Journal of the Optical Society of Korea
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    • v.20 no.1
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    • pp.169-173
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    • 2016
  • Terahertz (THz) generation by a GaP ridge waveguide with a collinear modal phase-matching scheme based on cascaded difference frequency generation (DFG) processes is theoretically analyzed. The cascaded Stokes interaction processes and the cascaded anti-Stokes interaction processes are investigated from coupled wave equations. THz intensities and quantum conversion efficiency are calculated. Compared with non-cascaded DFG processes, THz intensities from 11-order cascaded DFG processes are increased to 5.48. The quantum conversion efficiency of 177.9% in cascaded processes can be realized, exceeding the Manley-Rowe limit.

Chemical Constituents of Lonicera maackii Leaves (괴불나무잎(Lonicera maackii)의 성분)

  • Kim, Seon Mi;Won, Yong Hoon;Jeong, Kai;Kim, Myong Jo;Chun, Wanjoo;Yang, Hee Jung;Kwon, Yongsoo
    • Korean Journal of Pharmacognosy
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    • v.47 no.2
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    • pp.117-121
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    • 2016
  • Two flavonoid glycosides and three secoiridoide glycosides were isolated from the leaves of Lonicera maackii. On the basis of spectral and physico-chemical data, the structures of isolated compounds were identified as hesperetin-7-O-glucoside (1), luteolin-7-O-${\beta}$-D-glucopyranoside (2), secologanin dimethylacetal (3), epi-vogeloside (4), and vogeloside (5), respectively. Hesperetin-7-O-glucoside (1) was isolated for the first time from this plant.

A practice on performance testing for web-based systems Hyperlink testing for web-based system

  • Chang, Wen-Kui;Ron, Shing-Kai
    • International Journal of Quality Innovation
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    • v.1 no.1
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    • pp.64-74
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    • 2000
  • This paper investigates the issue of performance testing on web browsing environments. Among the typical non-functional characteristics, index of link validity will be deeply explored. A framework to certify link correctness in web site is proposed. All possible navigation paths are first formulated to represent a usage model with the Markov chain property, which is then used to generate test script file statistically. With collecting any existing failure information followed by tracing these testing browsed paths, certification analysis may be performed by applying Markov chain theory. The certification result will yield some significant information such as: test coverage, reliability measure, confidence interval, etc. The proposed mechanism may provide not only completed but also systemic methodologies to find any linking errors and other web technologies errors. Besides, an actual practice of the proposed approach to a web-based system will be demonstrated quantitatively through a certification tool.

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Embryonic Effects of Radiation on ICR Mice Depending Developmental Stages (ICR 마우스의 주요기관 형성기에 있어서 기형 발생의 시기특이성에 관한 실험적 검토)

  • Gu, Yeun-Hwa;Kusama, Tomoko;Kai, Michiaki
    • Journal of radiological science and technology
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    • v.18 no.1
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    • pp.91-95
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    • 1995
  • The ICR pregnant mice were irradiated at 1.5Gy in every 6 hours in the period of organogenesis in order to classify the stage specificity of the embryonic effects of radiation and the stage of development differentiation of the primordium of each major organ. Intrauterine death, fetal body weight and external malformation in live fetuses were observed on day 18 of gestation. There was no statistically significant difference in the intrauterine mortality at any stage organogenesis. The fetal body weight of the mice irradiated in the intermediate stage of organogenesis showed significantly lower. There were specific highly sensitive stages in the incidences of each external malformation, that is exencephalia, open eyelid, cleft palate, anomalies of extremities and anomalies of the tail. At these stage, the primordia of the major organs are established in ICR mice.

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CONTINUOUS DEPENDENCE PROPERTIES ON SOLUTIONS OF BACKWARD STOCHASTIC DIFFERENTIAL EQUATION

  • Fan, Sheng-Jun;Wu, Zhu-Wu;Zhu, Kai-Yong
    • Journal of applied mathematics & informatics
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    • v.24 no.1_2
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    • pp.427-435
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    • 2007
  • The existence theorem and continuous dependence property in $"L^2"$ sense for solutions of backward stochastic differential equation (shortly BSDE) with Lipschitz coefficients were respectively established by Pardoux-Peng and Peng in [1,2], Mao and Cao generalized the Pardoux-Peng's existence and uniqueness theorem to BSDE with non-Lipschitz coefficients in [3,4]. The present paper generalizes the Peng's continuous dependence property in $"L^2"$ sense to BSDE with Mao and Cao's conditions. Furthermore, this paper investigates the continuous dependence property in "almost surely" sense for BSDE with Mao and Cao's conditions, based on the comparison with the classical mathematical expectation.