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With the pervasive generation of information from a wide range of sensors and devices, there always exist a large number of input features in databases, thus complicating machine learning problem formulation. However, certain features are relatively impertinent to specific problems, which may degrade the performances of classifiers in terms of prediction accuracy, sensitivity,specificity, and recall rate. The main goal of a multi-objective optimization problem is to identify the subsets of the given features. To this end, a hybrid cat swarm optimization(HCSO) algorithm is proposed in our paper for performance improvement of the basic cat swarm optimization(CSO) that incorporates guided and competitive inherent characteristics into the original CSO. The performance of HCSO has been tested by finding the optimal feature subset for 15 benchmark datasets. The number of class labels for these datasets varies between 2 and 40. The time complexity analysis of both CSO and HCSO has also been evaluated. Moreover, the performance of the proposed algorithm has been compared with that of simple CSO and other state-ofthe-art techniques. The performances obtained by HCSO have an average 2.68% improvement with a standard deviation of 2.91.The maximum performance improvement is up to 10.09% in prediction accuracy. Tested on the same datasets, CSO has yielded improvements within the range of-7.27% to 8.51% with an average improvement 0.9% and standard deviation 3.96. The statistical tests carried out in the experiments prove that HCSO manifests a moderately better feature selection capacity than that of its counterparts.  相似文献   
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(Y,Gd)2O3:Eu(YGO:Eu)纳米粉体合成及透明陶瓷制备   总被引:1,自引:0,他引:1  
研究以碳酸氢铵作为沉淀剂制备Y1.34Gd0.6Eu0.06O3(YGO:Eu)纳米粉体的工艺,并采用真空烧结制备了YGO:Eu透明陶瓷.实验结果表明:以硝酸盐为母盐,以碳酸氢铵为沉淀剂,在本研究试验条件下获得的YGO先驱物为晶态的水合稀土碳酸钇钆正盐.先驱物在600℃煅烧后可以得到立方晶型的YGO粉体.煅烧温度对粉体的颗粒尺寸及尺寸分布有影响,1100℃煅烧所获得的粉体由粒径-100nm的球形颗粒组成,颗粒尺寸分布均匀,粉体具有较好的烧结性能.采用所制备的YGO:Eu纳米粉体,在1670℃真空烧结2h可获得透光性良好的透明陶瓷,样品在可见光区的最高透过率可达74.6%,高于相同工艺条件下制备的氧化钇透明陶瓷.  相似文献   
4.
In this work, diamond-like carbon (DLC) thin film coatings are deposited on silicon substrates by using plasma-enhanced chemical vapour deposition (PECVD) technique. By varying the hydrogen (H2) flow rate, CH4−Argon (Ar) flow rate and deposition temperature (Td) as per a Box-Behnken experimental design (BBD), 15 DLC deposition experiments are carried out. The Young’s modulus (E) and the coefficient of friction (COF) for the DLCs are measured. By using a second-order polynomial regression approach, two metamodels are built for E and COF, that establish them as functions of H2 flow rate, CH4-Ar flow rate and Td. A non-dominated sorting genetic algorithm (NSGA-III) is used to obtain a set of Pareto solutions for the multi-objective optimization of E maximization and COF minimization. According to various practical scenarios, evaluation based on distance from average solution (EDAS) approach is used to identify the most feasible solutions out of the Pareto solution set. Confirmation experiments are conducted which shows the efficacy of the polynomial regression—NSGA-III—EDAS hybrid approach. The surface morphology of the DLCs deposited as per the optimal predictions is also studied by using atomic force microscopy.  相似文献   
5.
目的 观察维脑路通及其各组分在人体内的药物动力学。方法 7 例患者静脉滴注维脑路通注射液600 mg 后, 用一种程序控制检测灵敏度的反相高效液相色谱法测定不同时间血清中维脑路通和各种羟乙基芦丁含量, 并分别计算其药物动力学。结果 维脑路通和一、二羟乙基芦丁在血清中的药物动力学为一室开放模型, 三、四羟乙基芦丁为二室开放模型, 各组分生物半衰期随羟乙基数目增加而缩短。结论 维脑路通的动力学过程与其组分并不呈现一致性。  相似文献   
6.
A series of new chiral side-chain liquid crystalline polymers with electron donor–acceptor action were prepared containing chiral monomer with donor group and nematic LC monomer with acceptor group. All polymers were synthesized by graft polymerization using polymethylhydrosiloxane as backbone. The mesomorphic properties were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), thermogravimetric analyses (TGA), and X-ray diffraction measurements (XRD). The chemical structures of monomers and polymers were confirmed by Fourier transform infrared (FTIR), proton nuclear magnetic resonance spectra (1H NMR and 13CNMR). M 1 did not show liquid crystalline phase and M 2 turned out nematic phase on heating and cooling cycle. Polymers P 2 P 7 were cholesteric phase. Cholesteric phase and low glass temperature liquid crystalline polymers have been obtained, which offered the possibility of application. Experimental results demonstrated that the glass-transition temperatures rose and isotropization temperatures decreased and the ranges of the mesophase temperature reduced with increasing the content of chiral agent. All of the obtained polymers showed high thermal stability.  相似文献   
7.
The most crucial task in real-time processing of steganography algorithms is to reduce the computational delay and increase the throughput of a system. This critical issue is effectively addressed by implementing steganography methods in reconfigurable hardware. In the proposed framework, a new high-speed reconfigurable architectures have been designed for Least Significant Bit (LSB) or multi-bit based image steganography algorithm that suits Field Programmable Gate Arrays (FPGAs) or Application Specific Integrated Circuits (ASICs) implementation. The architectures are designed and instantiated to implement the complete steganography system. The proposed system is competent enough to provide larger throughput, since high degrees of pipelining and parallel operations are incorporated at the module level. The evolved architectures are realized in Xilinx Virtex-II Pro XC2V500FG256-6 FPGA device using Register Transfer Level (RTL) compliant Verilog coding and has the capacity to work in real-time at the rate of 183.48 frames/second. Prior to the FPGA/ASIC implementation, the proposed steganography system is simulated in software to validate the concepts intended to implement. The hardware implemented algorithm is tested by varying embedding bit size as well as the resolution of a cover image. As it is clear from the results presented that the projected framework is superior in speed, area and power consumption compared to other researcher’s method.  相似文献   
8.
This study presents the design, processing, properties and potential applications of a novel layered bio-ceramic composites consisting of three different micro-porous calcium phosphate coatings on strong zirconia cores manufactured using a recently developed slip coating-deposition and coating-substrate co-sintering technique. Detailed microstructures of the three graded micro-porous calcium phosphate coatings, and the coating/substrate interface have been investigated. Also, the flexural strength of the bio-ceramic composite and the bonding state between the coatings and zirconia substrate have been characterized. A preliminary and limited in vitro cell test indicates that the new scaffold composite has no cytotoxicity to the fibroblasts which can attach, proliferate and grow on the coating surfaces. Because of the combination of bio-function and strength, such layered load-bearing bio-ceramic composites are a potential candidate for large-scale head bone repairs.  相似文献   
9.
基于传统B/S模式的实时信息显示系统通过定时刷新页面方式以实现动态信息的显示,存在效率低、与实际数据不同步等问题。引入基于发布/订阅模式的消息中间件,结合浏览器的插件技术组建航班信息显示系统,系统应用服务器将数据推送给消息中间件,消息中间件再将数据以消息的方式推送给单个或多个目标浏览器,达到动态信息实时显示的要求。测试结果表明,该系统具有页面响应快、服务器资源消耗率低等特点,且随着系统规模的不断增加,性能也能得到保证。  相似文献   
10.
An analysis of transverse cracks induced in brittle coatings on soft substrates by spherical indenters is developed. The transverse cracks are essentially axisymmetric and geometrically conelike, with variant forms dependent on the location of initiation: outer cracks that initiate at the top surface outside the contact and propagate downward; inner cracks that initiate at the coating/substrate interface beneath the contact and propagate upward; intermediate cracks that initiate within the coating and propagate in both directions. Bilayers consisting of hard silicon nitride (coating) on a composite underlayer of silicon nitride with boron nitride platelets (substrate), with strong interfacial bonding to minimize delamination, are used as a model test system for Hertzian testing. Test variables investigated are contact load, coating/substrate elastic-plastic mismatch (controlled by substrate boron nitride content), and coating thickness. Initiation of the transverse coating cracks occurs at lower critical loads, and shifts from the surface to the interface, with increasing elastic-plastic mismatch and decreasing coating thickness. This shift is accompanied by increasing quasi-plasticity in the substrate. Once initiated, the cracks pop in and arrest within the coating, becoming highly stabilized and insensitive to further increases in contact load, or even to coating toughness. A finite element analysis of the stress fields in the loaded layer systems enables a direct correlation between the damage patterns and the stress distributions: between the transverse cracks and the tensile (and compressive) stresses; and between the subsurface yield zones and the shear stresses. Implications of these conclusions concerning the design of coating systems for damage tolerance are discussed.  相似文献   
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