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71.
72.
The authors estimated trajectory of a created crack in a block-structured rock mass during hydraulic fracturing, and analyzed
effect of the parameters of the block medium and two-axis compression field on the main crack trajectory and on the opening
of lineal segments of the crack. 相似文献
73.
The authors use a two-dimension plane model to analyze seismic wave propagation in block-structured media under impulse loading.
Dynamics of the medium is described by means of pendulum approximation, where blocks are considered incompressible and deformation
and displacement occur via compressible intermediate layers. The simplest calculation model of a square lattice composed of
masses and springs connected in axial and diagonal directions is under discussion in the article. 相似文献
74.
A. Aguilar-Arevalo M. Blecher D.A. Bryman J. Comfort J. Doornbos L. Doria A. Hussein N. Ito S. Kettell L. Kurchaninov C. Malbrunot G.M. Marshall T. Numao R. Poutissou A. Sher B. Walker K. Yamada 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2009,609(2-3):102-105
An extension of the TRIUMF M13 low-energy pion channel designed to suppress positrons based on an energy-loss technique is described. A source of beam channel momentum calibration from the decay π+→e+ν is also described. 相似文献
75.
Talley Amelia E.; Tomko Rachel L.; Littlefield Andrew K.; Trull Timothy J.; Sher Kenneth J. 《Canadian Metallurgical Quarterly》2011,25(3):530
Previous research has shown that sexual minority (i.e., nonheterosexual) individuals report increased problematic substance use involvement, compared with their sexual majority counterparts. We hypothesize that feelings of an unstable sense of self (i.e., identity disturbance) may potentially drive problematic substance use. The purpose of the current study is to examine identity disturbance among sexual minorities as a potential explanatory mechanism of increased sexual minority lifetime rates of substance dependence. Measures of identity disturbance and three indicators of sexual orientation from lifetime female (n = 16,629) and male (n = 13,553) alcohol/illicit drug users in Wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) were examined. Findings generally showed that the increased prevalence of alcohol dependence, illicit drug dependence, and combined alcohol/illicit drug dependence as well as a younger age of alcohol use initiation among sexual minority women was associated with elevated levels of identity disturbance. The results were consistent with a mediational role for identity disturbance in explaining the association between sexual minority status and substance dependence and were generally replicated among male sexual minority respondents. The current research suggests that identity disturbance, a predictor of substance use, may contribute to heightened risk for substance dependence among certain subgroups of sexual minority individuals. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
76.
This paper deals with a human-assisted knowledge extraction method to extract “if…then…” rules from a small set of machining data. The presented method utilizes both probabilistic reasoning and fuzzy logical reasoning to benefit from the machining data and from the judgment and preference of a machinist. Using the extracted rules, one can determine the values of operational parameters (feed, cutting velocity, etc.) to ensure the desired machining performance (keep surface roughness within the stipulated range (e.g., moderate)). Applying the presented method in a real-life machining knowledge extraction situation and comparing it with the inductive learning based knowledge extraction method (i.e., ID3), the usefulness of the method is demonstrated. As the concept of manufacturing automation is shifting toward “how to support humans by computers”, the presented method provides some valuable hints to the developers of futuristic computer integrated manufacturing systems. 相似文献
77.
The possibility is investigated for failure of long rods under face impact caused by the stability loss of longitudinal deformation. The formula is obtained for calculating the maximum tensile stress during bending under the action of prescribed duration and intensity. 相似文献
78.
79.
N Ullah 《Canadian Metallurgical Quarterly》1996,53(4):4182-4183
80.
Modeling and simulation of intracellular dynamics: choosing an appropriate framework 总被引:2,自引:0,他引:2
Systems biology is a reemerging paradigm which, among other things, focuses on mathematical modeling and simulation of biochemical reaction networks in intracellular processes. For most simulation tools and publications, they are usually characterized by either preferring stochastic simulation or rate equation models. The use of stochastic simulation is occasionally accompanied with arguments against rate equations. Motivated by these arguments, we discuss in this paper the relationship between these two forms of representation. Toward this end, we provide a novel compact derivation for the stochastic rate constant that forms the basis of the popular Gillespie algorithm. Comparing the mathematical basis of the two popular conceptual frameworks of generalized mass action models and the chemical master equation, we argue that some of the arguments that have been put forward are ignoring subtle differences and similarities that are important for answering the question in which conceptual framework one should investigate intracellular dynamics. 相似文献