全文获取类型
收费全文 | 83篇 |
免费 | 3篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 1篇 |
综合类 | 17篇 |
化学工业 | 5篇 |
建筑科学 | 6篇 |
矿业工程 | 1篇 |
能源动力 | 3篇 |
水利工程 | 2篇 |
无线电 | 12篇 |
一般工业技术 | 13篇 |
冶金工业 | 2篇 |
原子能技术 | 27篇 |
自动化技术 | 4篇 |
出版年
2022年 | 3篇 |
2021年 | 2篇 |
2020年 | 5篇 |
2018年 | 1篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 7篇 |
2013年 | 8篇 |
2012年 | 4篇 |
2011年 | 13篇 |
2010年 | 4篇 |
2009年 | 11篇 |
2008年 | 2篇 |
2007年 | 5篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1994年 | 1篇 |
排序方式: 共有93条查询结果,搜索用时 0 毫秒
1.
金属陶瓷物理性能与材料组分和空间组织结构密切相关,其组成相的形态分布具有分形特征。基于渗流理论和分形理论,通过对材料微观结构图像的二值化处理进行导通相分形维数计算,建立分形维数与导通相微观形貌、渗流临界指数之间的定量表征,研究Mo-ZrO2金属陶瓷全组分范围内材料微观结构与电导率和热导率之间的关系。结果表明:导通相面积分形维数随着Mo体积分数的增加而增加,电导率与分形维数遵循渗流转变特征。采用通用有效介质(GEM)方程建立基于导通相分形维数的金属陶瓷电导率和热导率模型,实现材料微观组织定量分析结果与金属陶瓷的渗流模型相结合,有效预测材料宏观物理性质的梯度变化。 相似文献
2.
针对实验室GEM实时成像平板探测器多通道实时数据采集的需要,设计了一套基于FPGA和网络接口芯片的数据采集系统.该系统具有精度高、速度快、通道多、通用性强、安全可靠的特点,具有较高的应用价值. 相似文献
3.
孟艳琼 《武汉理工大学学报》2002,24(4):126-128,135
从我国目前的现实环境出发,理性地分析了我国现阶段推出创业所面临的问题,并有针对性地提出了一些对策和建议。 相似文献
4.
O. Bouianov M. Bouianov R. Orava P. Semenov V. Tikhonov 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2000,450(2-3):277-287
The charge induction mechanism and signal formation on the electrodes of the Gas Electron Multiplier (GEM) detector are discussed in detail. The method of simulating the effective gas gain, transparency and charge losses in GEM structures is developed. Results on simulation of various GEM geometries are consistent with published experimental data. 相似文献
5.
T. Tamagawa A. Hayato F. Asami K. Abe S. Iwamoto S. Nakamura A. Harayama T. Iwahashi S. Konami H. Hamagaki Y.L. Yamaguchi H. Tawara K. Makishima 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2009,608(3):390-396
We have produced thick-foil and fine-pitch gas electron multipliers (GEMs) using a laser etching technique. To improve production yield we have employed a new material, liquid crystal polymer, instead of polyimide as an insulator layer. The effective gain of the thick-foil GEM with a hole pitch of , a hole diameter of , and a thickness of reached a value of 104 at an applied voltage of 720 V. The measured effective gain of the thick-foil and fine-pitch GEM ( pitch, diameter, and thick) was similar to that of the thick-foil GEM. The gain stability was measured for the thick-foil and fine-pitch GEM, showing no significant increase or decrease as a function of elapsed time from applying the high voltage. The gain stability over 3 h of operation was about 0.5%. Gain mapping across the GEM showed a good uniformity with a standard deviation of about 4%. The distribution of hole diameters across the GEM was homogeneous with a standard deviation of about 3%. There was no clear correlation between the gain and hole diameter maps. 相似文献
6.
混合高斯参数估计的两种EM算法比较 总被引:1,自引:0,他引:1
混合高斯模型是一种典型的非高斯概率密度模型,获得广泛应用。其参数的优效估计可以通过最大似然方法获得,但最大似然估计往往因其非线性而难以实现,故期望最大化(Expectation-Maximization,EM)迭代算法成为一种常用的替代方法。常规EM算法性能受迭代初值设置影响大,且不能对模型阶数做出估计。一种名为贪婪EM的改进算法可以克服这两个缺点,获得更为准确的模型参数估计,但其运算量一般会远大于前者。本文对这两种EM算法进行综合研究,深入挖掘两者之间的关系,并基于相同的数值仿真实例,直观地演示比较两者的性能差异。 相似文献
7.
S. Procureur S. AuneJ. Ball Y. BedferM. Boyer H. Colas A. GiganonP. Konczykowski F. KunneC. Lahonde-Hamdoun N. MakkeC. Marchand O. MeunierA. Morreale B. MorenoH. Moutarde D. NeyretS. Platchkov F. Sabatié 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2011,659(1):91-97
A detailed study of several Micromegas detectors prototyped for the COMPASS and CLAS12 experiments is presented. Using a 150 GeV/c pion beam, the discharge probability was measured for several detector variants including bulk and non-bulk Micromegas. A detector equipped with an additional GEM foil as pre-amplification stage was also tested. A resistive coating of the readout strips was found to reduce the amplitude of the discharge by at least two orders of magnitude which was below the detection limit of the experimental setup. The effects of the micro-mesh type and material were investigated as well as the influence of the drift gap. Response in the presence of a 1.5 T transverse magnetic field was also studied. The measurements presented were performed during a RD51 beam test period. 相似文献
8.
9.
A. Orthen H. Wagner H. J. Besch R. H. Menk A. H. Walenta U. Werthenbach 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2003,500(1-3):163-177
A Micro compteur à Trous (MicroCAT) structure which is used for avalanche charge multiplication in gas filled radiation detectors has been optimised with respect to maximum electron transparency and minimum ion feedback. We report on the charge transfer behaviour and the achievable gas gain of this device. A three-dimensional electron and ion transfer simulation is compared to results derived from electric current measurements. Similarly, we present studies of the charge transfer behaviour of a Gas Electron Multiplier (GEM) by current measurements and simulations. Finally, we investigate the combination of the MicroCAT and the GEM by measurements with respect to the performance at different voltage settings, gas mixtures and gas pressures. 相似文献
10.
本文专门介绍由DVB标准化组织制订的GEM标准,内容包括GEM的由来和特点、标准的体系架构和组成部分、市场推广和应用情况以及标准未来的发展趋势等。 相似文献