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41.
本文利用85年5—6月间对乌鲁木齐市主要商业区及部分中、小商业区的实地调查资料,对乌市商业中心等级系统进行了定性和定量的分级分类,将全市商业中心划分为五个等级,八组商业中心,对已形成的商业中心分布现状进行了初步探讨,并对今后商业网点的合理布局提出了建议。 相似文献
42.
[1]中提出了具有功能反应的三种群捕食者——食饵系统的两种模型(Ⅰ)、(Ⅱ),并给出了局部渐近稳定的条件。本文研究了另外两种模型(Ⅲ)和(Ⅳ)的局部渐近稳定的条件。 相似文献
43.
重离子治疗计划系统的构想 总被引:2,自引:1,他引:1
对重离子柬治癌的优势进行简要的回顾,并着重介绍了用于重离子放射治疗的治疗计划系统。治疗计划系统是一套软件系统,不同的硬件设施应有与其相匹配的软件系统,即治疗计划系统。在此基础上,针对兰州重离子加速器的特点提出一些关于治疗计划系统方面的构想。After a brief review concerning the advantages of heavy ions in radiotherapy, more interests are concentrated on treatment planning system (TPS) for heavy ion radiotherapy. Compared to the hardware devices such as accelerator and beam delivery system, the TPS is a set of software system, and different therapy facilities require their corresponding TPSs. Based on the specialities of the Heavy Ion Research Facility in Lanzhou (HIIRFL), some suggestions on the TPS for tumor therapy at HIRFL finally are given. 相似文献
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In this paper, the transformations of generating systems of Euclidean space are examined in connection with the Drazin inverse of their Gram matrices and the notion of biorthogonal systems is generalized. The results obtained in this paper can be considered as the extension of some recent results concerning Moore-Penrose biorthogonal systems and reflexiveg-inverse systems in Euclidean spaces. 相似文献
47.
He Ping LIU Xuan Yuan ZHENG 《数学学报(英文版)》2006,22(2):425-430
We consider the commutators of the HSrmander multiplier with CMO-functions on the Heisenberg group. The result of compactness on L^P spaces is proved. 相似文献
48.
Huai-Chun Zhou Yu-Bo HouDong-Lin Chen Chu-Guang Zheng 《Journal of Quantitative Spectroscopy & Radiative Transfer》2002,74(5):605-620
A parallel-plane space filled with absorbing, emitting, isotropically scattering, gray medium is studied in this paper. The boundary intensity and boundary temperature profiles are calculated for the inverse analysis. For the simultaneous estimation of temperature, absorption and scattering coefficient profiles in the medium, the sum of residuals of boundary intensity and temperature after being weighted by a balance factor is minimized through using a Newton-type iteration algorithm and the least-squares method. To avoid over-updating for the parameters, the relative updating magnitude during the iteration process is constrained not to be >0.5. It is shown that the boundary intensity measurement alone is not enough to estimate simultaneously the temperature (source) and the radiative properties (both absorption and scattering coefficients) when the measurement data contain sensitive random errors. The boundary temperature measurement can serve as a necessary supplementation to the boundary intensity to make this kind of inverse radiative transfer problem resolvable. It was shown that a compensation relationship between absorption and scattering coefficients makes it difficult to fix them accurately. Parabolic profiles for the three parameters are used to validate the estimation method. When the optical thickness approaches 4.0, the results for the radiative properties are not acceptable, although the result for temperature profile is reasonable. This means the method needs further improvements. 相似文献
49.
A new formulation derived from thermal characters of inclusions and host films for estimating laser induced damage threshold has been deduced. This formulation is applicable for dielectric films when they are irradiated by laser beam with pulse width longer than tens picoseconds. This formulation can interpret the relationship between pulse-width and damage threshold energy density of laser pulse obtained experimentally. Using this formulation, we can analyze which kind of inclusion is the most harmful inclusion. Combining it with fractal distribution of inclusions, we have obtained an equation which describes relationship between number density of inclusions and damage probability. Using this equation, according to damage probability and corresponding laser energy density, we can evaluate the number density and distribution in size dimension of the most harmful inclusions. 相似文献
50.
HarmonicAnalysisontheCompactHomogeneousSpaces──aboutFourierMultiplierofH~P(M)Space¥DongDaozhen;ZhengXuean(HenanUniversity,Kai?.. 相似文献