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71.
Velocity Distribution of Turbulent Open-Channel Flow with Bed Suction   总被引:1,自引:0,他引:1  
This study investigates theoretically and experimentally the velocity distributions of turbulent open channel flow with bed suction. A velocity profile with a slip velocity at the bed surface and an origin displacement under the bed surface is proposed and discussed. Based on this assumption, a modified logarithmic law is derived. The measured experimental velocity distribution verifies the accuracy of the theoretically derived profile. The data show a significant increase in the near bed velocity and a velocity reduction near the water surface, resulting in the formation of a more uniform velocity distribution. The values of the origin displacement, slip velocity and shear velocity are found to increase with increasing relative suction. The measured data show the occurrence of two flow regions in the suction zone: a transitional region in which the velocity readjusts rapidly; and an “equilibrium” region.  相似文献   
72.
H.264/AVC FRExt (Fidelity Range Extensions) and Motion JPEG 2000 are the current respective inter-frame and intra-frame coding standards for high resolution (HR) (e.g., 4096 × 2160) visual signals. It is commonly believed that an inter-frame method could achieve higher coding efficiency compared with an intra-frame one, due to the exploitation of video temporal redundancy. However, Motion JPEG 2000 has been selected as the digital cinema compression standard, and some existing work has demonstrated that JPEG 2000 is more suitable at HR situations. In this paper, we compare the rate–distortion (R–D) performance of these two different schemes and give more insight from both theoretical and experimental point of view. We derive an entropy-based R–D model to analyze the test results and the impact of residual entropy and quantization for inter-frame coding. Several extensions are introduced into H.264/AVC FRExt for HR video content for better performance. Experimental results show that these extensions lead to significantly higher coding efficiency and make our extended version more suitable for HR video coding  相似文献   
73.
74.
In H.264/advanced video coding (AVC), lossless coding and lossy coding share the same entropy coding module. However, the entropy coders in the H.264/AVC standard were original designed for lossy video coding and do not yield adequate performance for lossless video coding. In this paper, we analyze the problem with the current lossless coding scheme and propose a mode-dependent template (MD-template) based method for intra lossless coding. By exploring the statistical redundancy of the prediction residual in the H.264/AVC intra prediction modes, more zero coefficients are generated. By designing a new scan order for each MD-template, the scanned coefficients sequence fits the H.264/AVC entropy coders better. A fast implementation algorithm is also designed. With little computation increase, experimental results confirm that the proposed fast algorithm achieves about 7.2% bit saving compared with the current H.264/AVC fidelity range extensions high profile.  相似文献   
75.
A 43‐year‐old Chinese man with chronic viral hepatitis and end‐stage renal disease, receiving conventional hemodialysis for 6 years, presented with general malaise and abdominal fullness. After 4.5 hours of hemodialysis, the hollow fibers of the dialyzer turned yellow. Biochemistry studies showed hyperbilirubinemia. The actual serum bilirubin (7.4 mg/dL) could be proved. Abdominal echography survey was negative. Hyperbilirubinemia was secondary to acute exacerbation of chronic viral hepatitis. Anuria and skin hyperpigmentation in uremia lack the tea‐color urine and mask clinical jaundice in the presence of hyperbilirubinemia. Careful observation of dialyzer yellowish discoloration gave us timely discovery of patient's hyperbilirubinemia.  相似文献   
76.
The design of a radio telescope is complex because, not only does it have to be light, but it has to satisfy a homological pattern of deflections. Often the structure is large and its analysis requires a great deal to computer time and storage. In this paper a method is presented to design such a structure so that it is light and certainly deflects homologically. An iterative method of design is used in which the surface joint deflections are specified and the aim is to calculate a set of cross-sectional areas that satisfy these deflections. This design method avoids the analysis of the structure and thus excludes the explicity solution of a large set of simultaneous equations. In this manner both computer time and storage are considerably reduced. Example are given to demonstrate the method.  相似文献   
77.
Mining regional co-location patterns with kNNG   总被引:2,自引:0,他引:2  
Spatial co-location pattern mining discovers the subsets of features of which the events are frequently located together in geographic space. The current research on this topic adopts a distance threshold that has limitations in spatial data sets with various magnitudes of neighborhood distances, especially for mining of regional co-location patterns. In this paper, we propose a hierarchical co-location mining framework accounting for both variety of neighborhood distances and spatial heterogeneity. By adopting k-nearest neighbor graph (kNNG) instead of distance threshold, we propose “distance variation coefficient” as a new measure to drive the mining operations and determine an individual neighborhood relationship graph for each region. The proposed mining algorithm outputs a set of regions with each of them an individual set of regional co-location patterns. The experimental results on both synthetic and real world data sets show that our framework is effective to discover these regional co-location patterns.  相似文献   
78.
Interoperability is defined as the ability for two (or more) systems or components to exchange information and to use the information that has been exchanged. There is increasing demand for interoperability between individual software systems. Developing an interoperability evaluation model between software and information systems is difficult, and becoming an important challenge. An interoperability evaluation model allows knowing the degree of interoperability, and lead to the improvement of interoperability. This paper describes the existing interoperability evaluation models, and performs a comparative analysis among their findings to determine the similarities and differences in their philosophy and implementation. This analysis yields a set of recommendations for any party that is open to the idea of creating or improving an interoperability evaluation model.  相似文献   
79.
Modern microscopic volumetric imaging processes lack capturing flexibility and are inconvenient to operate. Additionally, the quality of acquired data could not be assessed immediately during imaging due to the lack of a coherent real-time visualization system. Thus, to eliminate the requisition of close user supervision while providing real-time 3D visualization alongside imaging, we propose and describe an innovative approach to integrate imaging and visualization into a single pipeline called an online incrementally accumulated rendering system. This system is composed of an electronic controller for progressive acquisition, a memory allocator for memory isolation, an efficient memory organization scheme, a compositing scheme to render accumulated datasets, and accumulative frame buffers for displaying non-conflicting outputs. We implement this design using a laser scanning confocal endomicroscope, interfaced with an FPGA prototyping board through a custom hardware circuit. Empirical results from practical implementations deployed in a cancer research center are presented in this paper.  相似文献   
80.
Recent shape editing techniques, especially for man‐made models, have gradually shifted focus from maintaining local, low‐level geometric features to preserving structural, high‐level characteristics like symmetry and parallelism. Such new editing goals typically require a pre‐processing shape analysis step to enable subsequent shape editing. Observing that most editing of shapes involves manipulating their constituent components, we introduce component‐wise controllers that are adapted to the component characteristics inferred from shape analysis. The controllers capture the natural degrees of freedom of individual components and thus provide an intuitive user interface for editing. A typical model usually results in a moderate number of controllers, allowing easy establishment of semantic relations among them by automatic shape analysis supplemented with user interaction. We propose a component‐wise propagation algorithm to automatically preserve the established inter‐relations while maintaining the defining characteristics of individual controllers and respecting the user‐specified modeling constraints. We extend these ideas to a hierarchical setup, allowing the user to adjust the tool complexity with respect to the desired modeling complexity. We demonstrate the effectiveness of our technique on a wide range of man‐made models with structural features, often containing multiple connected pieces.  相似文献   
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