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排序方式： 共有132条查询结果，搜索用时 15 毫秒
1.
针对非理想报告信道环境中的认知无线电多用户协同频谱感知问题,建立了协同感知三层模型;以单用户为例,分析了报告信道传输错误对单用户感知性能的影响;同时,基于Newman—Pearson准则推导了统计值传输和判决值传输条件下的最优协同频谱感知方法,并给出了平坦瑞利衰落环境下感知性能的上限。 相似文献
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3.
小基站已成为运营商为用户提供更高数据业务速率和容量的重要技术手段,但随着小基站部署密度的增大,会导致很多问题的出现,如频繁的切换失败,回程链路的非理想化等等。通过进一步研究小基站的增强技术,可以更好地改善这种多层混合组网的整体性能。为解决这些问题,文章针对不同场景进行了增益分析,并给出了潜在解决方案,最后通过分析对比,找到比较合适的小基站增强技术。 相似文献
4.
Hakan Boyaci 《Sadhana》2006,31(1):1-8
A simply supported damped Euler-Bernoulli beam with immovable end conditions are considered. The concept of non-ideal boundary
conditions is applied to the beam problem. In accordance, the boundaries are assumed to allow small deflections and moments.
Approximate analytical solution of the problem is found using the method of multiple scales, a perturbation technique. 相似文献
5.
《工程爆破》2022,(6)
对炸药-岩石相互作用过程正确和全面的理解是研究岩石爆破破碎过程的基础。通过未反应炸药采用Murnahan状态方程、爆轰产物采用JWL方程、反应速率采用三项点火-增长-反应速率模型,改进了的炸药非理想爆轰模型。实验数据对比表明,改进的非理想爆轰模型能够较好地模拟工业炸药的非理想爆轰过程。基于改进的非理想爆轰模型,研究了不同装药结构和不同耦合介质下炸药与岩石的相互作用过程。研究表明,同种炸药在纵波速度不同的岩石中的爆轰结构存在显著差异,空气和水对爆轰冲击波有明显的缓冲和迟滞作用,与空气不耦合装药相比,水耦合装药荷载峰值高,持续时间长,具有更高的能量利用率,有利于改善破碎效果。 相似文献
6.
\"电子技术基础\"是实践性很强的课程,初学者往往不能理解电路的精髓.本文以电子滤波器为例,指出实际电路和理想电路的差异,元器件的非理想、非线性等因素对于电路性能指标的影响.对电子滤波器原理进行了分析,也进行了计算机仿真和实验验证,电子滤波器的滤波效果只有在一定条件下才能成立.本文对学生理解电子元件的参数特性有一定的参考价... 相似文献
7.
An optimized solar dish collector (OPSDC) system was proposed in our previous work, which can achieve excellent the optical efficiency and flux uniformity under ideal optics. On this basis, the impacts of the non-ideal optical factors on the optical performance of OPSDC system with a cylindrical and conical receiver are studied in detail and compared with the conventional solar dish collector (COSDC) system in this paper. Where the non-ideal optical factors considered are relatively comprehensive, including the mirror slope error, tracking error, installation error of the mirror and receiver, and receiver's absorptivity degeneration. An optical model with the non-ideal optical factors is built in detail by the ray tracing method, and the corresponding ray tracing codes are developed and verified by literatures and optical software OptisWorks 2012. The results show that the OPSDC system not only has a significantly smaller peak local concentration ratio (LCR) and non-uniformity factor than the COSDC system under the same non-ideal optical factor, but also has excellent optical performance. This means that OPSDC system can effectively avoid the heat absorber generating high-temperature hot spots, thus significantly improving its working reliability and service lifetime. In addition, the tracking error, installation error of the receiver and mirror all lead to the increase of the peak LCR and non-uniform factor, while the mirror slope error and absorber's absorptivity degeneration are conducive to reducing the peak LCR and non-uniform factor. This work can provide a reference for error control of COSDC system and OPSDC system in manufacturing, installation and operation. 相似文献
8.
《Propellants, Explosives, Pyrotechnics》2018,43(3):280-285
Detonation heats of RDX‐based non‐ideal explosives containing 15, 30 and 45 % of Al, (Al/ZrH2), TiH2 and ZrH2 were measured with a water calorimeter set. To get more information on the behaviour of the additives in the detonations performed in an argon atmosphere, the solid post‐detonation products extracted from the calorimetric bomb were analysed to determine their elemental and phase compositions. The calorimetric heats were compared with the detonation energies obtained from thermochemical calculations. All the tested explosives produce more energy during detonation in the bomb than RDX itself, but only aluminium positively influences the total energy release. The results of thermal and XRD analyses indicate that post‐detonation products contain mainly carbonaceous materials, metal oxides, unreacted hydrides and/or the metals. Unexpectedly TiH2 is the least reactive additive. At TiH2 content of 45 %, the heat effect is close to that of calculated with an assumption of complete inertness of the additive. Moreover TiH2 and metallic titanium are present in the bomb residues in a significant amount. 相似文献
9.
Terahertz (THz) radiation can be generated due to the instability of THz plasma waves in field-effect transistors (FETs). In this work, we discuss the instability of THz plasma waves in the channel of FETs with spin and quantum effects under non-ideal boundary conditions. We obtain a linear dispersion relation by using the hydrodynamic equation, Maxwell equation and spin equation. The influence of source capacitance, drain capacitance, spin effects, quantum effects and channel width on the instability of THz plasma waves under the non-ideal boundary conditions is investigated in great detail. The results of numerical simulation show that the THz plasma wave is unstable when the drain capacitance is smaller than the source capacitance; the oscillation frequency with asymmetric boundary conditions is smaller than that under non-ideal boundary conditions; the instability gain of THz plasma waves becomes lower under non-ideal boundary conditions. This finding provides a new idea for finding efficient THz radiation sources and opens up a new mechanism for the development of THz technology. 相似文献
10.
针对目前旋变软件解码中的采样包络面存在非理想偏差问题,从理论推导了幅值偏差、直流偏差会对旋变软件解码的输出角度叠加一个2倍频波动,正交偏差会叠加一个同频波动。提出了基于离散傅里叶变换(DFT)的矫正方法,利用该方法实现了幅值偏差、直流偏差和正交偏差的提取,并对这3种偏差设计了相应的矫正环节。同时又推导了存在转速误差条件下使用DFT方法提取到的幅值偏差、直流偏差存在一个和旋变包络面初始相位相关的波动误差,并通过取一段时间内波动平均值的方法解决了该误差对提取结果的影响。最后通过仿真试验验证了推导的正确性,搭建了拖台架并进行旋变标定试验,对比标定前后数据,表明偏差矫正后的锁相环输出的角度线性度更好,转速波动更小,相应的dq轴电流的指定阶次波动也更小。 相似文献