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71.
周世忠 《电脑编程技巧与维护》2012,(2):97-98
JSP中变量的定义有全局和局部之分,局部变量并不会带来安全问题,而对全局变量的使用,就要慎之又慎。内置对象application的使用要特别注意线程安全。此外,JavaBean的使用也要注意线程安全问题,特别是当scope属性设置为application的时候。 相似文献
72.
基于SaaS的矿震远程预警系统关键技术初探 总被引:1,自引:1,他引:0
现有的矿震预警系统都是以独立形式运行于各矿区,相互之间没有关联,重复投资严重,且矿震数据海量繁杂,仅依靠现场分析无法满足实时预警需求。文章基于感知矿山物联网示范工程(夹河矿),对采用云计算SaaS模式构建的矿震远程预警系统关键技术进行了相关研究:首先给出了系统整体框架,然后重点探讨了该系统所涉及的三个关键技术,包括基于SaaS的矿震预警专家分析软件架构、多源SaaS数据库构建技术以及基于MapReduce的并发数据过滤接收技术。现场应用表明,所构建的系统已基本具备全国统一远程矿震预警系统的架构,能满足多矿区远程矿震预警的基本要求。 相似文献
73.
为改善石英晶体振荡器的频率特性,减小温度影响,通过对石英晶体振荡器的频率-温度特性的研究,提出了以微处理器(STC89C52RC)为核心的基于AT切晶体谐振器的温度补偿技术,并介绍了系统结构、补偿原理及硬件电路,给出了补偿结果。本设计具有结构简单、功耗低等优点。 相似文献
74.
崔怀坤 《网络安全技术与应用》2012,(1):73-75
本文首先简要的介绍了几种关于计算机犯罪定义的学说,然后对刑法意义上的"计算机犯罪概念"进行了定位,最后论述了计算机犯罪的犯罪构成,为刑法理论和司法实践中准确认定该类犯罪提供了具体依据。 相似文献
75.
Jian‐Peng Cui Feng Zhou Chengqun Song Quan‐Min Zhong Qiong‐Hua Wang 《Journal of the Society for Information Display》2012,20(6):347-350
Abstract— A low‐voltage (~10 Vrms) and high‐transmittance (~90%) polymer‐stabilized blue‐phase liquid‐crystal (BPLC) device with a slanted‐electrodes structure is proposed. Unlike the vertical‐field‐switching (VFS) mode in which oblique incident light and a vertical field are employed, the proposed device utilizes normal incident light and an oblique field. The slanted electrodes generate a strong and uniform oblique electric field, which contributes in obtaining low voltage and high transmittance. Moreover, no couple films or prism sheets are needed, which helps to enhance the optical efficiency and simplify of the device structure. This device has great potential application for emerging BPLC displays and photonic devices. 相似文献
76.
Weige Lu Haisong Xu M. Ronnier Luo 《Journal of the Society for Information Display》2012,20(5):259-265
Abstract— A psychophysical experiment was carried out to assess the perceptual contrast on a large‐sized liquid‐crystal display (LCD) under nine phases of viewing conditions. Based on the results, six contrast models employing different color attributes or the index of just‐noticeable difference (JND) were developed. Their performances were also tested by the visual data of the nine phases, which indicated that the model CQ employing CIECAM02 brightness gives the best performance in predicting visual data under different viewing conditions among those models. A preprocessing step was also proposed to utilize the contrast model CQ conveniently in the practical contrast evaluation of LCDs. 相似文献
77.
Hillel Tal-Ezer 《Journal of scientific computing》1989,4(1):25-60
In solving a mathematical problem numerically, we frequently need to operate on a vector by an operator that can be expressed asf(A), whereA is anN ×N matrix [e.g., exp(A), sin(A), A–-]. Except for very simple matrices, it is impractical to construct the matrixf (A) explicitly. Usually an approximation to it is used. This paper develops an algorithm based upon a polynomial approximation tof (A). First the problem is reduced to a problem of approximatingf (z) by a polynomial in z, where z belongs to a domainD in the complex plane that includes all the eigenvalues ofA. This approximation problem is treated by interpolatingf (z) in a certain set of points that is known to have some maximal properties. The approximation thus achieved is almost best. Implementing the algorithm to some practical problems is described. Since a solution to a linear systemAx=b isx=A
–1
b, an iterative solution algorithm can be based upon a polynomial approximation tof (A)=A
–1. We give special attention to this important problem. 相似文献
78.
Experimental vapor pressures andP--T data of an important alternative refrigerant, 1, 1-difluoroethane (HFC-152a), have been measured by means of a constant-volume method coupled with expansion procedures. SixtyP--T data were measured along eight isochores in a range of temperaturesT from 330 to 440 K, at pressuresP from 1.6 to 9.3 MPa, and at densities from 51 to 811 kg·m–3. Forty-six vapor pressures were also measured at temperatures from 320 K to the critical temperature. The uncertainties of the temperature and pressure measurements are within ±7mK and ±2kPa, respectively, while the uncertainty of the density values is within ±0.1%. The purity of the sample used is 99.9 wt%. On the basis of the measurements along each isochore, five saturation points were determined and the critical pressure was determined by correlating the vapor-pressure measurements. The second and third virial coefficients for temperatures from 360 to 440 K have also been determined. 相似文献
79.
The specific heat at constant pressure, C
p, of aluminum measured by Ditmars, Plint, and Shukla has been reduced to the volume V
0 appropriate for 0 K employing the Murnaghan equation. The C
v0 thus obtained is compared with the theoretical C
v0 calculated in the harmonic and the lowest-order anharmonic approximation from three different pseudopotentials (Harrison, Ashcroft, and Dagens-Rasolt-Taylor) as well as a phenomenological Morse potential. The higher-order (
4) anharmonic contributions are calculated from the same nearest-neighbor Morse potential as in the lowest-order anharmonic theory. The role of the vacancy and the higher-order anharmonic contributions to C
v0 has been examined and we conclude that the
4 contributions to C
v0 are much smaller than the vacancy contribution. After removal of the vacancy contribution, the reduced C
v0 is found to be in excellent agreement with the Ashcroft and Harrison pseudopotentials as well as the Morse potential including the
2 and
4 contributions to C
v0. 相似文献
80.