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41.
We discuss an attentional model for simultaneous object tracking and recognition that is driven by gaze data. Motivated by theories of perception, the model consists of two interacting pathways, identity and control, intended to mirror the what and where pathways in neuroscience models. The identity pathway models object appearance and performs classification using deep (factored)-restricted Boltzmann machines. At each point in time, the observations consist of foveated images, with decaying resolution toward the periphery of the gaze. The control pathway models the location, orientation, scale, and speed of the attended object. The posterior distribution of these states is estimated with particle filtering. Deeper in the control pathway, we encounter an attentional mechanism that learns to select gazes so as to minimize tracking uncertainty. Unlike in our previous work, we introduce gaze selection strategies that operate in the presence of partial information and on a continuous action space. We show that a straightforward extension of the existing approach to the partial information setting results in poor performance, and we propose an alternative method based on modeling the reward surface as a gaussian process. This approach gives good performance in the presence of partial information and allows us to expand the action space from a small, discrete set of fixation points to a continuous domain.  相似文献   
42.
PURPOSE: A number of peptidases which can metabolize certain bioactive peptides and growth factors have been identified in seminal plasma. Our goal in this study was to determine molecular properties and the tissue source(s) for one of these peptidases, dipeptidylpeptidase IV (DPP IV), in human seminal plasma. MATERIALS AND METHODS: We measured the activities of DPP IV with the dipeptide glycylprolyl-p-nitroanalide and its molecular forms using immunoblotting of seminal plasmas of men who were vasectomized or with different sperm concentrations, and in prostatic and seminal vesicle secretions of men undergoing prostatic surgery. RESULTS: DPP IV in seminal plasma of vasectomized men was a membrane associated dimer comprised of subunits of approximately 110 kDa. Its activity did not differ in seminal plasmas of vasectomized, azoospermic, oligozoospermic and normozoospermic men indicating no correlation with the concentration of sperm originally present in the semen. The DPP IV antigen (CD -26) and enzymic activity were present in prostatic secretion, but absent from that of the seminal vesicles. These data indicate that the prostate gland is the primary source of DPP IV activity in seminal plasma. There was little variation in its activities in repeat seminal plasma samples from the same individual, and there was no change in its activity with age to 50 years. CONCLUSIONS: DPP IV in seminal plasma was derived from the prostate gland and it may be useful as a bioindicator of prostate function and/or disease with age in men.  相似文献   
43.
A hydrophilic surface suitable for solid‐state peptide synthesis was developed on a solid support called a lantern. The split‐and‐mix combinatorial technique was used to prepare about 500 surfaces in a very short time. Surfaces were analyzed according to values for gel formation, percentage weight grafted, grafted copolymer composition, and number of functional groups per lantern. These values were correlated to the purity of a peptide synthesized on these surfaces. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3371–3378, 2003  相似文献   
44.
Microwave effects on drosophila morphogenesis were studied. Drosophila embryo were exposed by continuous wave 460 MHz at SAR = 1-5 Wt/kg. It was found that irradiation induced some morphosis such as imago legs and wings form alterations. These effects depended on embryo age, SAR and period exposure. It was proposed that the local microwave heating is responsible for describe effects.  相似文献   
45.
A multi-matcher for ear authentication   总被引:1,自引:0,他引:1  
In this work we propose a local approach of 2D ear authentication. A multi-matcher system is proposed where each matcher is trained using features extracted from a single sub-window of the whole 2D image. The features are extracted by the convolution of each sub-window with a bank of Gabor Filters, then their dimensionality is reduced by Laplacian EigenMaps. The best matchers, corresponding to the most discriminative sub-windows, are selected by running the Sequential Forward Floating Selection (SFFS). Our experiments, carried out on a database of 114 people, show that combining only few (ten) sub-windows in the fusion step it is possible to achieve a very low Equal Error Rate.  相似文献   
46.
This paper is a thorough overview on polysilicon bipolar junction transistors’ (BJTs) reliability, with focus on transistors for digital applications, where the base–emitter junction switches from forward to reverse bias (low fields) and the base–collector junction is reverse biased at high fields. The effects of base–emitter reverse biasing are generation, charging and discharging of traps in silicon oxide or at the Si–SiO2 interface near the base–emitter junction; their understanding is essential to model transistor current gain degradation and low frequency noise increase. Failure modes and mechanisms, degradation kinetics, lifetime models and physical phenomena related to device aging will be discussed. The base–emitter junction is also stressed by high currents, which lead, for example, to electromigration phenomena. The base–collector junction degradation is mainly due to high field and impact-ionization effects. Reliability constraints are now an important component of a correct design methodology in deep-sub-micron integrated circuits.  相似文献   
47.
48.
We demonstrate high-efficiency thin-film silicon solar cells with transparent nanotextured front electrodes fabricated via ultraviolet nanoimprint lithography on glass substrates. By replicating the morphology of state-of-the-art nanotextured zinc oxide front electrodes known for their exceptional light trapping properties, conversion efficiencies of up to 12.0% are achieved for micromorph tandem junction cells. Excellent light incoupling results in a remarkable summed short-circuit current density of 25.9 mA/cm(2) for amorphous top cell and microcrystalline bottom cell thicknesses of only 250 and 1100 nm, respectively. As efforts to maximize light harvesting continue, our study validates nanoimprinting as a versatile tool to investigate nanophotonic effects of a large variety of nanostructures directly on device performance.  相似文献   
49.
Luigi Angiolini  Loris Giorgini 《Polymer》2011,52(13):2747-2756
Novel optically active methacrylic homopolymers bearing in the side chain one or more chiral groups of one single configuration (l-lactic acid residue) linked to tetraphenylporphyrin have been successfully synthesized and fully characterized.These intrinsically chiral polymers exhibit remarkable thermal stability, with glass transition temperature in the range 250-315 °C and decomposition temperatures in the range 360-390 °C. Spectroscopic, thermal and chiroptical characterizations indicate the occurrence of dipolar interactions among the side chain moieties and the presence of chiral helix conformation at least for chain segments of the macromolecules.The macromolecular Zinc-porphyrin material resulted capable to bind optically active α,ω-diamine guests through nitrogen/zinc coordination to form complexes exhibiting exciton-coupled bisignate Circular Dichroism (CD) spectra with signs related to the absolute configuration of the guest compound. This behavior is due to the formation of diastereomeric complexes which lead to a preferred porphyrin helicity, at least for chain segments. The method turns out to be very sensitive, requiring only few micrograms of guest compound.  相似文献   
50.
Multi-layered panels are often used to improve the acoustics in cars, airplanes, rooms, etc. For such an application these panels include porous and/or fibrous layers. The proposed numerical method is an approach to simulate the acoustical behavior of such multi-layered panels. The model assumes plate-like structures and, hence, combines plate theories for the different layers. The poroelastic layer is modelled with a recently developed plate theory. This theory uses a series expansion in thickness direction with subsequent analytical integration in this direction to reduce the three dimensions to two. The same idea is used to model either air gaps or fibrous layers. The latter are modeled as equivalent fluid and can be handled like an air gap, i.e., a kind of ‘air plate’ is used. The coupling of the layers is done by using the series expansion to express the continuity conditions on the surfaces of the plates. The final system is solved with finite elements, where domain decomposition techniques in combination with preconditioned iterative solvers are applied to solve the final system of equations. In a large frequency range, the comparison with measurements shows very good agreement. From the numerical solution process it can be concluded that different preconditioners for the different layers are necessary. A reuse of the Krylov subspace of the iterative solvers pays if several excitations have to be computed but not that much in the loop over the frequencies.  相似文献   
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