模拟退火遗传算法在多声源定位中的应用

利用声源定位技术测量弹丸落点坐标时,针对多发炮弹短间隔连续射击试验中,传感器接收信号的时序关系复杂,严重影响声源定位结果准确性的问题,提出了采用模拟退火遗传算法实现短间隔连续多声源目标的精确定位。试验测试了发射间隔为0.15 s的7发炮弹在600 m×600 m区域内的定位情况,结果表明:文章的算法能快速有效的对短间隔连续多声源目标进行定位解算,定位精度小于5 m。     

对基岩应变与基岩地电前兆和地震发震时间之间所遵循的二倍时关系的初步探讨

由于地震机理的复杂性,前兆现象和地震三要素之间究竟存在何种规律性的联系,尚未完全揭示.目前仍处于探索阶段. 近来。在一些地震预报工作中。提出了二倍时方法.认为某些前兆的出现时刻与发震时刻之间满足二倍时关系.具体地说,就是若前兆 P出现的时间为t1,前兆Q出现的时间为t2,两次前兆间的时间间隔t=t2-t1,则可以预言在t3= t1 2(t2-t1)=t1 2t时,有可能发生一次相应的地震(图1).在有些二倍时法中前兆是某种物理量发生突变或异常,在另外一些二倍时法中,前兆也可以是某种物理量达到极值或约定值.在简单情况下,P和Q就是相继出现的两次前兆.…     

高温高压下钠长石的阻抗谱实验研究

 在压力为1.0、2.0 GPa和温度为673～973 K条件下,采用交流阻抗谱法在YJ-3000t紧装式六面顶高压设备上原位测量了钠长石的电导率。实验结果表明：在实验的温度和压力范围内,钠长石的电导率在10^-3.0～10^-5.5 S/m变化;钠长石复阻抗的模和相角对频率有很强的依赖性;随着温度T升高,钠长石的电阻率迅速减小,电导率σ增大,并且lg σ与T^-1之间符合Arrhenius关系;在实验压力范围内,随着压力升高,钠长石的电导率降低。采用离子导电机制,对高温高压下钠长石的导电行为进行了合理解释。     

一个非晶硅薄膜太阳能电池制备用激光刻线系统

 非晶硅薄膜太阳能电池制备过程中的激光刻线工艺要求刻线宽度在30 μm～50 μm之间,死区范围小于300 μm,刻线深度符合工艺要求。这不仅要求激光器具有较高的光束质量,而且要求光学系统具有较高的成像质量和较宽的焦深。设计了单激光器四分光路的激光刻线系统。采用设计的激光刻线装置,在1 400 mm×1 100 mm×3.2 mm玻璃基板上进行刻线试验,分别得到刻线P1,P2,P3的线宽为35 μm,50 μm和45 μm,死区范围（P1至P3的距离）为287 μm,最终深度分别为0.98 μm,0.24 μm和0.58 μm,刻线宽度和深度均符合薄膜太阳能电池制备工艺要求。     

砂土的突破压力与渗透率实验

符号表A截面积，m2p压力，PaV体积流量，m3／sd颗粒平均粒径，mpc毛细压力，pa孔隙率dth突破直径，mPth突破压力，Pa黏度，kg/(m.s）k渗透率，m2，半径，表面张力，N／mL长度，m1前言三参数模型曾经再现了某种意义的毛细滞后现象[1]，但对于存在边界影响的典型重力脱湿和毛细吸湿过程始终未能模拟[2]。重要的原因是边界上的两相流体如何处于平衡并不十分清楚。窄筛分沙水中自然沉积的表层实验表明，气体进入湿饱和多孔介质存在一个压力阈值Pth。低于突破阈值时，气体与湿介质处于随遇平衡，只有达到这个值时，气体才能突破表层阻挠进人…     

超导电性二流体模型的适用性

给出了由 2 B t=1α B t导出 2 B=1αB和由 js t=nse2m E导出 js=ensυs的证明 ,从而解决了 L ondon方程的理论缺陷 ,并讨论了 2 B t=1α B t与 2 B=1αB及 js t=nse2m E与 js=ensυs的适用性问题     

单轴恒速燃气轮机及其功热并供装置的变工况显式解析解

主要符号表Ci，i=1～4压气机特性式中常数G流量m压气机设计转速线延长线与Gc轴交点N功率n转速P压力P压气机设计转速线延长线与Gc轴两支点距功热比T温度ti，i=1～4透平特性式中常数Z总能利用率α下标β0设计参数△Tα逼近温差△Tp节点温差n效率θ经济效率[3]μ流量比π压比T温比总压恢复系数上标折合参数比折合参数下标0设计参数1，2压气机进、出口3，4透平进、出口5余热锅炉燃气出口b燃烧室C压气机F油耗gt燃气轮机当量效率[3]饱和蒸汽t透平w余热锅炉给水1绪言如何检验各种变工况数值解程序的准确度与有效性以及各种算法的适用性，通常…     

利用深海海底声反射区频域干涉结构的声源深度估计方法

提出了一种基于深海海底声反射区声场频域干涉结构特征的水下宽带近海面声源深度估计方法。该方法通过建立深海海底声反射区到达声场结构模型,推导了垂直阵接收信号波束输出幅度谱的近似表达式,利用幅度谱与声源深度和垂直到达角(俯仰角)之间的周期变化关系,将接收信号映射到深度-垂直到达角域中,实现了对宽带声源的深度估计。仿真实验与影响因素分析验证了该原理的正确性,南海实验结果表明:利用阵长为64 m的垂直短阵接收标定深度为50 m和100 m的双弹信号,得到的深度估计结果同实际声源深度吻合较好,估计误差不超过7%,验证了该方法的有效性。     

塑料超声熔焊特性的研究Ⅰ

对塑料超声熔焊特性进行了研究，烙焊过程中高频电功率可分为三个阶段，t1振动摩擦发热，t2熔焊为一体，t3能量过剩．熔焊拉力强度F随着单位体积所消耗高频电能P增加而提高，达到饱和状态，F达到他和后，继续增加P烙焊件焊缝凸起．本研究为开发自动熔焊设备和提高馆焊质量提供有用信息     

基于时域多普勒修正的运动声全息识别方法

由于运动声源测量信号中多普勒效应的存在,一般声全息方法无法直接使用,而阵列信号波束成形处理方法无法进行定量分析.本方法建立了基于测量面、辐射面和全息面的运动学几何关系,提出了声源与测量信号之间的非线性时间映射方法,基于运动声源的声源特征函数,构造了消除多普勒效应的全息面时域声压分布.全息重建得到运动声源表面有效声压分布,实现了对主要声源处声压幅值的定量估计.实际运动声源的测量实验结果证明了该方法的有效性.     

Stability of the proton-to-electron mass ratio

We report a limit on the fractional temporal variation of the proton-to-electron mass ratio as 1/(m(P)/m(e)) partial differential/partial differential(t)(m(P)/m(e))=(-3.8+/-5.6) x 10(-14) yr(-1), obtained by comparing the frequency of a rovibrational transition in SF6 with the fundamental hyperfine transition in Cs. The SF6 transition was accessed using a CO2 laser to interrogate spatial 2-photon Ramsey fringes. The atomic transition was accessed using a primary standard controlled with a Cs fountain. This result is direct and model-free.     

Self- and mutual-diffusion coefficients measurements by 31P NMR 1D profiling and PFG-SE in dextran gels

31P NMR 1D profiling was successfully introduced to measure macroscale mutual-diffusion coefficients (D(m)) of phosphate ions in dextran gels. Series of 1D profiles describing the phosphate concentration along cylindrical dextran gels were acquired at different times. These profiles that included over 600 points could be fitted using equations derived from Fick's law, with D(m) as the single fitting parameter. Release and penetration profiles were recorded providing two alternative approaches for allowing the determination of D(m). The D(m) values were compared with microscale self-diffusion coefficients (D(s)) measured by pulsed field gradient spin echo (PFG-SE) technique. D(m) values, measured between 25 and 45 degrees C, were systematically lower than D(s). The experimental diffusion time and the associated diffusion length of D(s) (60 ms, 10 microm) are short compared to those of D(m) (up to 18 h, 50 mm). These scale differences are considered to be the origin of different D(s) and D(m) and provide information relative to the network in these gels.     

GaAs衬底的固态杂质源脉冲1.06μm激光诱导扩散

利用１．０６αｍ脉冲Ｎｄ：ＹＡＧ激光，以含Ｚｎ的固态杂原在化合物半导体ＧａＡｓ基片上进行诱导扩散，作出了Ｐ－Ｎ结。获得了亚微米的的散结结深及１ｃｍ＾－３量级的表面掺杂浓度，并利用二次离子质谱仪对扩散样品进行成发的逐层扫描分析，研究了结深和掺杂浓度与辐照激光脉冲数，单脉冲数激光能量密度的关系。     

New scaling law for the decay exponent of bimolecular reactions in unbounded transitional flows

We propose a new scaling law for global kinetics of the stoichiometric reaction A+B-->P in unsteady, transitional flows. We find in the nonlinear flow regime the decay as approximately t(-alpha) where alpha is related to a space-time scaling parameter psi as alpha proportional, variant psi(m), for the considered parameter range m=0.067. In the linear flow regime, we find that the maximum is alpha approximately 2/3 for psi approximately 1. The proposed scaling law should be useful for linking dynamical subgrid processes with reaction kinetics in a variety of transitional flow systems.     

Search for pair production of scalar top quarks decaying to a tau lepton and a b quark in pp over collisions at sqrt s=1.96 TeV

We search for pair production of supersymmetric top quarks (t over1), followed by R-parity violating decay t over1-->taub with a branching ratio beta, using 322 pb(-1) of pp over collisions at sqrt s=1.96 TeV collected by the upgraded Collider Detector at Fermilab. Two candidate events pass our final selection criteria, consistent with the standard model expectation. We set upper limits on the cross section sigma(t over1t over1) x beta2 as a function of the top-squark mass m(t over1). Assuming beta=1, we set a 95% confidence level limit m(t over1)>153 GeV/c2. The limits are also applicable to the case of a third-generation scalar leptoquark (LQ3) decaying LQ3-->taub.     

Weakly nonlinear analysis of the magnetorotational instability in a model channel flow

We show by means of a perturbative weakly nonlinear analysis that the axisymmetric magnetorotational instability (MRI) of a viscous, resistive, incompressible rotating shear flow subject to a background vertical magnetic field in a thin channel gives rise to a Ginzburg-Landau equation for the disturbance amplitude. For small magnetic Prandtl number (P(m)), the saturation amplitude is proportional square root P(m) and the resulting momentum transport scales as R(-1), where R is the hydrodynamic Reynolds number. Simplifying assumptions, such as linear shear base flow, mathematically expedient boundary conditions, and continuous spectrum of the vertical linear modes, are used to facilitate this analysis. The asymptotic results are shown to comply with numerical calculations using a spectral code. They suggest that the transport due to the nonlinearly developed MRI may be very small in experimental setups with P(m)<1.     

Pressure-Stabilized New Phase of CaN_4

We propose a new CaN_4 high pressure structure with the P2_1/m space group.The P2_1/m-CaN_4 structure is constituted by the infinite armchair N-chain.The dynamical stability and mechanical stability are verified by the calculations of phonon dispersion curves and elastic constants.The enthalpy difference calculation shows that the P2_1/m phase is more stable than the reported P4_12_12 phase.The advantaged properties of P2_1/m-CaN_4,such as high nitrogen content(58.3%) and low polymerization pressure(18.3 GPa),allow it to be a potential high energy materlal.Band structure calculation shows that the P2_1/m-CaN_4 structure is a metallic phase.The nonpolar covalent single N-N bond is a sigma bond.The charge transfer between the Ca and N atoms results in an ionic bond interaction.     

压力高达27 GPa下天然奥长石的XRD分析

在室温高达27 GPa压力下对天然奥长石(Na_0.86K_0.02Ca_0.12Mg_0.01(Fe_0.01Al_1.12Si_2.87O₈))粉晶进行了原位同步辐射X光衍射(XRD)测量,获得了样品的状态方程。实验数据表明随着压力增大奥长石样品在大约3.5 GPa发生了三斜向单斜的相变(P1→C2)和在大约10.0 GPa发生了单斜对称相变(C2→C2/m)。样品三个相的体模量计算值分别为K₀=73.8 GPa (K′=10.98), K_(C2)=124 GPa (K′=1.05) 和K_(C2/m)=272 GPa (K′=0.625)。样品的元素组成影响其T-O-T 键角的刚度、M-O键的强度和Si-O-Al键角的弯曲,从而导致奥长石样品在高压行为的特殊变化。三斜相的奥长石晶胞压缩性具明显的各向异性。实验结果表明在冷俯冲带奥长石可能是碱金属和碱土金属深循环的载体。     

基于激光主动探测的“猫眼效应”研究

 针对基于“猫眼效应”的激光主动探测技术在光电对抗中的广泛应用,建立了迎面观瞄光电装置光学系统反光指数数学模型,并结合探测组件建立了探测距离数学模型,模拟了反光指数与内部特性参数间的数值关系及探测距离与迎面观瞄光电装置主要参数间的数值关系。为了验证建立的数学模型的正确性,利用研制的激光主动探测装置,分别以2.5 mm、5.5 mm孔径角镜和25 mm、35 mm、56 mm孔径光电观瞄装置为目标,进行了最大探测距离模拟和验证实验,模拟值分别为1 290 m、1 656 m、866 m、1 919 m、1 226 m,实验值分别达到1 100 m、1 500 m、800 m、1 800 m、1 200 m。结果表明：最大探测距离模拟值和实验值有很好的一致性。