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仪器缺少维修及养护直接影响测报工作的完成,以 S L1 型翻斗式遥测雨量计为例,从仪器的结构原理出发,介绍仪器的维修和养护方法,并简单论述仪器维护的重要性,提出一些搞好仪器维护的建议。 相似文献
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As an important part of water level warning in water conservancy projects, often due to the influence of en-vironmental factors such as light and stains, the acquired water gauge images have sticky, broken and bright spot conditions, which affect the identification of water gauges. To solve this problem, a water gauge image denoising model based on improved adaptive total variation is proposed. Firstly, the regular term exponent in the adaptive total variational equation is changed to an inverse cosine function; secondly, the differential curvature is used to distinguish the image noise points and increase the smoothing strength at the noise points; finally, according to the characteristics of the gradient mode and adaptive gradient threshold after Gaussian filtering, the New model can adaptively denoise in the smooth area and protect the edge area, so as to have the characteristics of both edge-preserving denoising. The experimental results show that the new model has a great improvement in image vision, higher iteration efficiency and an average increase of 1.6 dB in peak signal-to-noise ratio, and an average increase of 9% in structural similarity, which is more beneficial to practical applications. 相似文献
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基于IGA的板形板厚神经网络分散解耦PID控制 总被引:1,自引:0,他引:1
针对板带材轧制是一个复杂的非线性过程,板形控制(AFC)和板厚控制(AGC)又是相互耦合的一个综合系统等特点.该文首先采用神经网络分散解耦方法,对此板形板厚多变量耦合系统进行解耦,而后再应用基于免疫遗传算法的PID控制对解耦后的已近似成为两个独立的SISO系统的广义对象进行控制。从而建立了基于免疫遗传算法的板形板厚神经网络分散解耦PID控制系统。仿真结果证明了此AFC—AGC控制系统具有良好的自适应跟随和抗扰性能,其控制效果优于传统的解耦PID控制。 相似文献
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武钢、宝钢两套冷连轧机代表了冷连轧技术发展水平 ,用连轧张力理论对这两套冷连轧机的厚控系统作了深入的分析、讨论 ,给出了其中最主要厚控环节 -连轧AGC和张力AGC的数学模型。对宝钢厚控系统提出了改进方案 ,利用DAGC可以简便地实现穿带、正常轧制、抛尾 ,而不用分别采用APC、恒压力、压力AGC三种控制方式 ,并且DAGC实现恒压力控制有更高的稳定性。 相似文献
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Imetrum Video Gauge is a commercial image-based two-dimensional displacement measurement system which has been widely used. Its uncertainty analysis is presented in this paper. First, the procedure to use Video Gauge is introduced. Then, based on the measurement model, two major sources of uncertainty are identified: (1) the uncertainty associated with the calibration procedure u(C) which is composed of the uncertainty of the known length used in calibration u(L) and the uncertainty of the projection of the known length in the image u(D) and (2) the uncertainty associated with the measurement system itself u(P). Following the Guide to the Expression of Uncertainty in Measurement, the uncertainties can be quantified. In the end, 60 experiments are performed to analyze the relationship between the measurement uncertainty and the working parameters, which are working distance, acquisition frequency and focal length of the lens. In order to ensure the validity of the calculation, two calculation methods are used. The main results of this paper are as follows: (1) the displacement measurement uncertainty increases along with working distance and decreases with the increase of focal length. At the same time, the results indicate that using a longer known length in calibration can also reduce the measurement uncertainty. (2) u(C) is greatly influenced by the known length used in the calibration procedure. It can be reduced when u(L) is reduced. (3) Under the laboratory circumstances, reducing u(C) can greatly reduce the total measurement uncertainty. (4) The displacement measurement uncertainty is more sensitive to the measurement uncertainty of the known length used in calibration than the projection of the known length in the image. (5) As the working distance grows, the sensitivity to the known length is getting weaker and the sensitivity to the projection of the known length in the image is getting stronger. (6) When a longer focal length lens is used, the influence of the working distance to the sensitivity gets weaker. The reported results can help people better understand the characteristics of this system and better use the system for their own purposes. 相似文献
8.
Emmanuel Creusé Patrick Dular Serge Nicaise 《Computers & Mathematics with Applications》2019,77(6):1563-1582
In this paper, we deal with some magnetostatic models considered in vector potential formulations and solved by a Finite Element solver. In order to ensure the uniqueness of the solution, a gauge condition has to be imposed, and several possibilities occur. Moreover, the source term has to be correctly defined to ensure a physically admissible solution. We show the equivalence between some of these choices for several kinds of boundary conditions. Moreover, we highlight their characteristic behaviors on some numerical benchmarks to illustrate our theoretical results. 相似文献
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《Measurement》2014
A simple method for reducing the uncertainty of reference standards has been proposed for gauge block comparator calibration. Errors due to the reference value of the length difference for mechanical comparator evaluation can be reduced by using the average of two reference values. Two reference values of length difference are obtained by the appropriate combination of three gauge blocks. Errors caused by reference gauges are canceled and averaged. An error reduction effect was successfully demonstrated using an actual mechanical comparator. 相似文献
10.
《Measurement》2016
Reliable data with less variation play a key role for acceptance of the usefulness of the measurement output of a wheel profile measurement system (WPMS) in a railway network. However, in practice, most studies are carried out without checking the reliability of data from such a system, which may lead to inappropriate maintenance strategies. To ensure the measurement capability of WPMS and to support robust maintenance in railway systems, this study has evaluated measurement data for the flange height, flange thickness, flange slope, and tread hollowing of rolling stock wheels by using gauge repeatability and reproducibility (GR&R). In this study, acceptance and rejection criteria for the precision-to-tolerance ratio (PTR), signal-to-noise ratio (SNR), and discrimination ratio (DR) have been employed to evaluate the measurement capabilities. For the purpose of illustration, we have implemented a new proposed approach. This approach involves both an analysis using graphs with four regions with a confidence interval (CI) of 95% and an analysis using a graph with three regions with only the predicted values; the latter type of graph represents an innovation made in this study. This graph has the advantages that it can visualize three different levels of data quality in same figure, namely “unacceptable”, “acceptable” and “good”, and also include a number of measures without becoming unclear, which are features that have been missing in previous presentations. The results show that the measurements of the flange slope are on an acceptable level, while those for the flange height, flange thickness and tread hollowing have to be rejected as unacceptable. The action proposed for increasing the quality of data on the flange height, flange thickness and tread hollowing is to enhance the calibration of the WPMS. In conclusion, GR&R is a useful tool to evaluate the measurement capability of WPMS and to provide helpful support for maintenance decision making. This investigation also shows that there is good reason to be careful when selecting measures and when interpreting the results, since, for a certain wheel profile parameter, when one measure is used, the results may be acceptable, but when another measure is used, the results may be unacceptable. 相似文献