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31.
Simulations of crystal deformation and structural transformation may generate complex datasets involving networks with million to billion chemical bonds which makes local structure analysis a challenge. An ideal analysis method must recognize perfect crystal structures, such as face-centered cubic, body-centered cubic and hexagonal close packed, and differentiate structural defects such as dislocations, stacking faults, grain boundaries, cracks and surfaces. Currently a few methods are used for this purpose, e.g., the Common Neighbor Analysis (CNA) and the Centrosymmetry Parameter (CSP). This paper proposes an alternative method based on the calculation of a single parameter that depends on the common atomic neighborhood. We validate the method characterizing local structures in complex molecular-dynamics datasets, clarifying its advantages over the CNA and the CSP methods.  相似文献   
32.
The development of compression techniques is crucial for several applications that require efficient storage and transmission of large data volumes. Fractal theory has been used in image and video compression due to advantages such as resolution independence, high compression rate, fast decoding, among others. Fractal compression approaches explore the presence of self-similarity to remove data redundancy, allowing high compression while maintaining low quality degradation. Early fractal compression methods presented prohibitive encoding time related to the search for similar regions in the image or video. This work describes a low bit-rate 3D searchless fractal video encoder to perform fast compression with high visual fidelity. Experiments demonstrate that the results of the proposed approach are superior when compared to those obtained by state-of-the-art x264 video encoder at very low bit rates in high motion video sequences.  相似文献   
33.
A parameter‐less adaptive penalty scheme for genetic algorithms applied to constrained optimization problems is proposed. Using feedback from the evolutionary process the procedure automatically defines a penalty parameter for each constraint. The user is thus relieved from the burden of having to determine sensitive parameter(s) when dealing with every new constrained optimization problem. The procedure is shown to be effective and robust when applied to test problems from the evolutionary computation literature as well as several optimization problems from the structural engineering literature. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
34.
In the age of speech and voice recognition technologies, sign language recognition is an essential part of ensuring equal access for deaf people. To date, sign language recognition research has mostly ignored facial expressions that arise as part of a natural sign language discourse, even though they carry important grammatical and prosodic information. One reason is that tracking the motion and dynamics of expressions in human faces from video is a hard task, especially with the high number of occlusions from the signers’ hands. This paper presents a 3D deformable model tracking system to address this problem, and applies it to sequences of native signers, taken from the National Center of Sign Language and Gesture Resources (NCSLGR), with a special emphasis on outlier rejection methods to handle occlusions. The experiments conducted in this paper validate the output of the face tracker against expert human annotations of the NCSLGR corpus, demonstrate the promise of the proposed face tracking framework for sign language data, and reveal that the tracking framework picks up properties that ideally complement human annotations for linguistic research.
Christian Vogler (Corresponding author)Email:
Siome GoldensteinEmail:
  相似文献   
35.
We report a novel mechanical response of few-layer graphene, h-BN, and MoS(2) to the simultaneous compression and shear by an atomic force microscope (AFM) tip. The response is characterized by the vertical expansion of these two-dimensional (2D) layered materials upon compression. Such effect is proportional to the applied load, leading to vertical strain values (opposite to the applied force) of up to 150%. The effect is null in the absence of shear, increases with tip velocity, and is anisotropic. It also has similar magnitudes in these solid lubricant materials (few-layer graphene, h-BN, and MoS(2)), but it is absent in single-layer graphene and in few-layer mica and Bi(2)Se(3). We propose a physical mechanism for the effect where the combined compressive and shear stresses from the tip induce dynamical wrinkling on the upper material layers, leading to the observed flake thickening. The new effect (and, therefore, the proposed wrinkling) is reversible in the three materials where it is observed.  相似文献   
36.
Learning functions defined on non-flat domains, such as outer surfaces of non-rigid shapes, is a central task in computer vision and geometry processing. Recent studies have explored the use of neural fields to represent functions like light reflections in volumetric domains and textures on curved surfaces by operating in the embedding space. Here, we choose a different line of thought and introduce a novel formulation of partial shape matching by learning a piecewise smooth function on a surface. Our method begins with pairing sparse landmarks defined on a full shape and its part, using feature similarity. Next, a neural representation is optimized to fit these landmarks, efficiently interpolating between the matched features that act as anchors. This process results in a function that accurately captures the partiality. Unlike previous methods, the proposed neural model of functions is intrinsically defined on the given curved surface, rather than the classical embedding Euclidean space. This representation is shown to be particularly well-suited for representing piecewise smooth functions. We further extend the proposed framework to the more challenging part-to-part setting, where both shapes exhibit missing parts. Comprehensive experiments highlight that the proposed method effectively addresses partiality in shape matching and significantly outperforms leading state-of-the-art methods in challenging benchmarks. Code is available at https://github.com/davidgip74/Learning-Partiality-with-Implicit-Intrinsic-Functions  相似文献   
37.
38.
Mutations or polymorphisms in the gene of the enzyme methylenetetrahydrofolate (MTHFR) are associated with hyperhomocysteinemia and possibly with an elevated risk for vascular diseases. A study was conducted on 83 individuals with type 2 diabetes in order to determine the allelic and genotypic frequencies of the G1793A mutation and to assess the effect of folic acid supplementation on plasma homocysteine concentrations. The patients were attended by the Diabetes and Hypertension Program--Balneario Camboriu/SC and received daily supplements containing 1 mg of folic acid for 3 months. DNA was previously extracted from leukocytes and the G1793A mutation was detected by PCR-RFLP. Blood samples were collected during the basal period and after supplementation for the determination of homocysteine by HPLC, and of folic acid and vitamin B(12) by RIA. The allele frequency for the G1793A mutation was 3.01% and no homozygous individuals with mutant alleles were detected. Hyperhomocysteinemia was diagnosed in 27.71% of the patients, folic acid deficiency in 15.66%, and vitamin B(12) deficiency in 7.23%. Plasma homocysteine concentrations were inversely correlated with folic acid (r = -0.27, p = 0.01) and vitamin B(12) (r = -0.21; p = 0.05) concentrations. The individuals with a heterozygous genotype for the G1793A mutation showed borderlines or deficient values in folic acid and vitamin B(12) concentrations compared to individuals with a normal genotype. Hyperhomocysteinemia and the vitamin deficiencies presented by type 2 diabetic individuals, included with a heterozygous genotype for the G1793A mutation in the MTHFR gene, reached normal values by daily folic acid supplementation.  相似文献   
39.
ABSTRACT

This survey describes the occurrence of Ethephon (ETH) and Fosetyl in fruits intended for export produced in the São Francisco Valley, Brazil. The determination of these compounds was carried out by the QuPPe-method (Quick Polar Pesticides Method), which was optimised and successfully validated according to the SANTE/11813/2017. From January 2016 to December 2018 a total of 1048 samples were analysed for ETH residues. In 547 (53%) of the samples, residues below the EU MRL of 1 mg kg?1 were present. In 17 samples (2%) ETH residues were above 1 mg kg?1. Overall, the mean ETH level decreased after 2016. Analyses of fosetyl showed that (18%) of 109 mango samples were positive for this compound. Phosphonic acid was found in concentrations ranging from 0.12 to 3.2 mg kg?1 and 5% of the measurements were above the EU MRL of 2 mg kg?1. The results emphasise the quality control of fruits produced in this region.  相似文献   
40.
J. B. Watson's Behaviorism, a complete presentation of the mature psychological points of view of its author, had 2 editions, in 1925 and 1930, which presented significant differences in their texts. Although Watson maximized such variations, to the point of considering the 2nd edition as nearly a brand-new book, both suppressions and additions reveal his feelings when presenting his ideas to a general audience. Such variations are here presented through an in-depth analysis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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