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991.
提出了一种基于模型驱动的元数据管理方案.方案采用了基于模型的形式化描述方法,统一了专业网管子系统间的元数据模式;通过引入模型驱动技术,从元模型的抽象层次消除了不同专业网管子系统之间存在的“信息孤岛”;方案还对综合网管环境下的元数据理论和交换机制进行了研究,并给出了元数据的管理框架以及元数据交换的Java接口映射. 相似文献
992.
Bifurcations of Invariant Tori and Subharmonic Solutions of Singularly Perturbed System 总被引:1,自引:1,他引:0
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This paper deals with bifurcations of subharmonic solutions and invariant tori generated from limit cycles in the fast dynamics for a nonautonomous singularly perturbed system. Based on Poincare map, a series of blow-up transformations and the theory of integral manifold, the conditions for the existence of invariant tori are obtained, and the saddle-node bifurcations of subharmonic solutions are studied. 相似文献
993.
本文根据1978—2003年中国农村居民现金消费支出数据,综合考虑影响消费的主要因素来研究中国农村居民的现金消费行为。与以往研究不同的是,对于影响消费支出的不确定性因素,本文不是采用某个具体变量进行近似替代,而是采用刻画不确定性的条件异方差来描述。文章的结论是农村居民现金消费支出的主要影响因素并非收入,而是利率和不确定性因素,不确定性因素在1996年后表现得尤为突出。 相似文献
994.
本文首先针对散乱数据拟合的Shepard方法,结合截断多项式、B样条基函数和指数函数来构造其权函数,使新的权函数具有更高的光滑度和更好的衰减性,并且其光滑性和衰减性可以根据实际需要自由调节,从而提高了曲面的拟合质量.同时还给出一种类似的局部插值方法.另外,本文还基于多重二次插值,结合多元样条的思想,给出了两个局部插值算法.该算法较好地继承了多重二次插值曲面的性质,从而保证了拟合曲面具有好地光顺性和拟合精度.曲面整体也具有较高的光滑性. 相似文献
995.
The generalized Morrey spaces are introduced under the hypothesis that Rn is endowed with the general parabolic metric , and the boundedness properties are established in generalized Morrey spaces for a class of singular integral operators, which include Calderon-Zygmund singular integrals and their commutators with BMO. 相似文献
996.
Summary The enzymes a-amylase, invertase and glucoamylase were immobilized on acid activated montmorillonite using two techniques,
viz. adsorption and covalent binding, and their activities were tested in a batch and packed-bed reactor and were compared. The
packed-bed reactor showed an improved performance for all immobilized enzymes, which was attributed to lowering of diffusional
restrictions to mass transfer. Lower activity in case of batch reactor for immobilized invertase was due to a combined effect
of loss of native conformation of enzyme on account of immobilization and mass transfer resistances due to improper diffusion
of substrate to the active site of enzyme. For immobilized glucoamylase, the packed-bed reactor demonstrated exceptionally
high activity that was very close to the free enzyme. Covalently bound glucoamylase showed higher activity than the free enzyme. 相似文献
997.
Excitation Properties of the Biological Neurons with Side-Inhibition Mechanism in Small-World Networks 总被引:3,自引:0,他引:3
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We have studied the excitation properties of biophysical Hodgkin-Huxley neurons with the side-inhibition mechanism in small-world networks. The result shows that the excitation properties in the networks are preferably consistent with the characteristic properties of a brain neural system under external constant stimuli, such as fatigue effect, extreme excitation principle, and the brain neural excitation response induced by different in- tensity of noise and coupling. The results of the study might shed some light on the study of the brain nerve electrophysiology and epistemological science. 相似文献
998.
By means of a formal analogy with the Aharonov-Bohm effect, the Sagnac time delay and the corresponding Sagnac phase shift in the Kerr-Newman and Reissner-Nordstrfm spacetimes are discussed. We find that the effect depends on the properties of the source of the gravitational field. The contributions made by the electric charge of the gravitational source can be employed to weaken it in the Kerr-Newman spacetime, even if a phase shift and a time delay still appear. This is due to the properties of the rotating source of the gravitational field. 相似文献
999.
进行了百万大气压下,静水压和非静水压条件下的压力校准,同时观察到金刚石砧容器中红宝石R线红移至830nm处,由校准公式算得对应的压强为5.5Mbar。
关键词: 相似文献
1000.
A Novel Analytical Approach for Multi-Layer Diaphragm-Based Optical Microelectromechanical-System Pressure Sensors
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An optical microelectromechanical-system (MEMS) pressure sensor based on multi-layer circular diaphragm is described and analysed by using the proposed novel analytical approach and the traditional transfer matrix method. The analytical expressions of the deflection of multi-layer diaphragm and absolute optical reflectance are derived respectively. The influence of residual stress on the deflection of diaphragm is also analysed. Simulation results given by the finite element method are consistent with the ones which are analysed by using the analytical approach. The analytical approach will be helpful to design and fabricate the optical MEMS pressure sensors with multi-layer diaphragm based on Fabry-Perot interferometry. 相似文献