Electronic protection and routing optimization of MANETs operating in an electronic warfare environment

Domination of the electromagnetic spectrum is a crucial component of the 21st century warfare. In the harsh electromagnetic environment of the modern battlefield, it is of the utmost importance to deny the opposing force the opportunity to attack or exploit the detection/interception of friendly communications assets through the deployment of electronic protection (EP) measures in order to attain low probability of detection (LPD), low probability of interception (LPI) and anti-jam (A/J). Given that directional antennas are a suitable means to achieve both extended range and LPD/LPI, this paper proposes mechanisms to optimize the trade-off between these capabilities, minimizing the number of hops and end-to-end delay when routing packets in a multi-hop ad-hoc network, while taking into account stealth requirements. The novel scheme is based on a variant of Fisheye State Routing, coupled with a power control algorithm to guarantee a LPD/LPI beyond the zone covered by the omni-directional radiation footprint of the network. The performance of the proposed scheme is evaluated through computer simulation.     

低k氟化非晶碳层间介质对芯片性能的影响

讨论了通过合理设计的工艺流程将低k氟化非晶碳材料应用到制造工艺中作为互连介质对集成电路性能的影响。基于一个互连结构简化模型计算出采用低k氟化非晶碳材料作为互连介质后RC延迟、功率耗散和线间串扰的变化情况。采用低k氟化非晶碳介质后,RC延迟和功率耗散随着互连长度的增大而减小,线间串扰也得到显著抑制。     

Visualization and quantification of the mechanical deformation induced by an electrical field in poly(ethylene naphthalene 2,6‐dicarboxylate) (PEN) films

An optical nondestructive strain measurement technique was performed to analyze the mechanical deformation induced by an electrical field within the insulating materials. Poly(ethylene naphthalene 2,6‐dicarboxylate) (PEN) films were then subjected to constant electrical fields right up to their electrical breakdown. The experimental technique made it possible to follow the various stages of the mechanical behavior of PEN in real time. The final breakdown occurred in the observation zone and the related mechanical deformation was captured. A “margarita” structure was observed with a hole at the center. The experimental results indicated that the level of the induced‐mechanical deformations depended on the local environment. We defined two different zones representing the inside and the outside of the damaged area. The induced‐deformations were larger in the damaged zone. It was also observed that deformations increased when the sample had a lower degree of crystallinity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Local dynamics in epoxy coatings containing iron oxide nanoparticles by dielectric relaxation spectroscopy

Nanocomposites of photocurable epoxy resin and epoxy‐modified iron oxide magnetic nanoparticles were analyzed by dielectric relaxation spectroscopy to study the local dynamics at temperatures well below the glass‐transition temperature. Two secondary processes were detected, β and γ processes, but the second one was just detected at lower temperatures in the high‐frequency part of the spectra and moved out of the frequency range at higher temperatures. Data were fitted to the Havriliak–Negami and Arrhenius models, and the obtained parameters were analyzed. Relaxation times of the β secondary relaxation did not change with the nanoparticle content, but the relaxation strength increased. The increase could not be explained when we took into account the molecular origin of the relaxation. The presence of ferromagnetic nanoparticles enhanced the internal field and increased the relaxation strengths. Transmission electron microscopy images showed that the nanoparticles were well dispersed in the matrix, without magnetic agglomerates. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

以循环移位控制为基础的相控阵天线快速测量方法研究

为了解决相控阵天线快速测试问题,本文研究了一种相控阵天线测量的新方法。该方法中相控阵天线和测试探头均不动,利用相控阵天线中各移相器的移相状态可循环移位控制的特点和相控阵天线一些已知可信的信息,从而使测量具有极高的效率。文中对一相控阵天线模型采用该测量方法的测量全过程进行模拟,验证了该方法的正确性和高效性。     

Optically tuned superconductive-dielectric resonators with whispering-gallery modes

An analytical method is presented for calculating the resonant frequency andQ-factor of a superconducting dielectric disk resonator operating in millimeter-wave regime with whispering-gallery mode. Resonant frequency shift due to the optical generation of quasi-particles in superconducting film is investigated as a function of photon flux. An optically tunable resonant frequency of about 500 MHz is estimated, and good agreement is found between numerical results and experimental ones.     

电容器介质吸收电流的测量和表征

在外电场作用下，电容器介质的吸收电流和漏电电流混杂而难以分开，但外电场除去后吸收电流对电容器放电总电荷所贡献的百分比具有确定值，吸收电流的释放遵从自由弛豫规律。可用响应时间ｒ’表征。实验给出了一些常见介质的吸收电流表征参数。     

ZST微波陶瓷在介质振荡器上的应用研究

用传统固相法制备ZST(氧化锆-氧化锡-氧化钛)系微波陶瓷,研究了ZST系微波陶瓷的组成对介电性能的影响。通过X-射线衍射(XRD)和HP8714ET网络分析仪对其晶体结构和微波介电性能进行研究,实验结果表明:少量掺Bi2O3的ZST系陶瓷材料可把烧结温度降低至1 260℃,微波介电性能较好;掺入量大于2%(质量分数)时,ZST系微波陶瓷在晶界偏析形成了Bi2Ti2O7新相,微波性能下降。用微波介电性能较好的ZST系陶瓷制成的介质振荡器进行测试,其电性能满足设计要求。     

高功率二极管泵浦固体激光技术和应用前景的分析

文章对高功率二极管泵浦固体激光器的若干关键技术，包括激光二极管和增益介质，泵浦，耦合和冷却技术，以及光学谐振腔等作了详细的分析。     

Sound-velocity measurements for HFC-134a and HFC-152a with a spherical resonator

A spherical acoustic resonator was developed for measuring sound velocities in the gaseous phase and ideal-gas specific heats for new refrigerants. The radius of the spherical resonator, being about 5 cm, was determined by measuring sound velocities in gaseous argon at temperatures from 273 to 348 K and pressures up to 240 kPa. The measurements of 23 sound velocities in gaseous HFC-134a (1,1,1,2-tetrafluoroethane) at temperatures of 273 and 298 K and pressures from 10 to 250 kPa agree well with the measurements of Goodwin and Moldover. In addition, 92 sound velocities in gaseous HFC-152a (1,1-difluoroethane) with an accuracy of ±0.01% were measured at temperatures from 273 to 348 K and pressures up to 250 kPa. The ideal-gas specific heats as well as the second acoustic virial coefficients have been obtained for both these important alternative refrigerants. The second virial coefficients for HFC-152a derived from the present sound velocity measurements agree extremely well with the reported second virial coefficient values obtained with a Burnett apparatus.Paper dedicated to Professor Joseph Kestin.