基于瞬变电磁法的整合矿井火区分布探测方法

 针对资源整合矿井火区探测中普通探测技术耗时长、工程量大,且难以直接定位火区范围等问题,研究了基于瞬变电磁法的火区分布探测方法。以北祖矿为例,在井下全空间条件下,结合地质资料和现场地质情况,采用瞬变电磁仪对北祖矿9209 风巷上覆煤层进行超前探测和剖面探测,反演计算形成超前、剖面视电阻率图,根据巷道上覆煤层在视电阻率图中的响应特征,通过定性分析确定巷道上覆煤层的自然发火区域。结果表明,基于瞬变电磁法的整合矿井火区分布探测方法能够准确定位火区分布范围,可为打钻探测及灌浆堵漏等矿井防灭火工程提供科学依据,明显提高工程效率及效果。     

基于串扰判决反馈信道均衡算法的语音通信系统设计

在强电磁干扰环境下,由于语音通信受到通信信道的快速时变衰落和码间干扰的影响,导致信道不均衡,降低了语音通信质量。提出一种基于串扰判决反馈信道均衡的语音通信系统的设计方法。该方法采用横向滤波器进行电磁干扰滤波器设计,利用语音通信信息传输信道频率特性的逆大于信息自身带宽的特征,通过调整均衡器参数进行,进行串扰判决反馈设计,结合信道自适应均衡处理技术,进行强干扰环境下语音通信信道均衡,以达到语音通信系统的优化。系统仿真结果表明,该语音通信优化系统具有抗电磁干扰能力及滤波性能较好、输出信噪比高、通信距离远、通信速度快、可靠性高等优点。     

Isospin structure in 68Ge

The interacting boson model-3(IBM-3) has been used to study the low-energy level structure and electromagnetic transitions of 68Ge nucleus. The main components of the wave function for some states are also analyzed respectively. The theoretical calculations are in agreement with experimental data, and the 68Ge is in transition from U(5) to SU(3).     

基于Biexponential基电流传输线通道模型的地闪回击近场电磁环境

地闪回击过程中产生的雷电电磁脉冲作为一种场强幅度大,频谱分量复杂的高功率电磁脉冲,其在回击近场区会形成极为复杂的电磁环境。随着微电子技术的快速发展,微电子设备电磁敏感度大大提升,从三维空间入侵的雷电电磁脉冲对于电子及电气设备的电磁危害不仅限于干扰其正常工作,更有甚者会造成设备的损毁。利用基于Biexponential基电流函数的传输线通道模型,模拟地闪回击物理过程以研究回击近场区综合电磁环境。研究结果表明:利用基于时域有限差分法的XFDTD电磁场仿真软件,可以便利地获得形象直观的回击近场区三维电磁场分布情况。回击近场区复杂的电磁环境会严重影响电子设备的正常运行,近场区LEMP的电磁危害不可小觑。     

Electromagnetic solitons in a system of graphene planes with Anderson impurities

We consider the Maxwell equations for the electromagnetic-field propagation in a system of graphene planes with Anderson impurities. A phenomenological equation is obtained in the form of an analog of the classical 1 + 1-dimensional sine-Gordon equation. Electrons are considered within the quantum formalism taking into account the dispersion-law variations in the presence of an impurity subsystem. The phenomenological equation is analyzed numerically. It was found that the formation of a forbidden band in the graphene spectrum influenced the propagation of ultrashort optical pulses.     

微波腔内波混沌散射的初步研究

 通过建立的微波腔模拟产生大量腔体散射矩阵和辐射散射矩阵,并转化得到归一化散射矩阵和阻抗矩阵。利用戴桑环系综对归一化散射矩阵的本征值和本征相位进行了统计分析,其本征值的模和本征相位具有统计独立性,且本征相位近似均一分布,验证了腔体中波混沌散射的存在。对数值模拟和随机矩阵理论预测得到的归一化阻抗的统计特性进行了比较,其结果基本一致,说明随机矩阵理论对归一化阻抗具有一定的预测功能。     

Changes in the polarization, the coherence and the spectrum of partially coherent electromagnetic Hermite–Gaussian beams in turbulence

The unified theory of coherence and polarization is applied to an investigation of the changes in the polarization, the coherence and the spectrum of partially coherent electromagnetic Hermite–Gaussian (EHG) beams propagating through atmospheric turbulence. Based on the extended Huygens–Fresnel principle, the 2×2 electric cross-spectral density matrix of partially coherent EHG beams in turbulence is expressed analytically by using a quadratic approximation of Rytov's phase structure function. The analytical expressions for the degree of polarization, the degree of coherence and the spectrum of partially coherent EHG beams in turbulence are derived, and the corresponding analytical results of electromagnetic Gaussian Schell-model (EGSM) beams can be obtained when the order number of the Hermite polynomial is zero. Some interesting results are obtained, which are illustrated by using numerical examples.     

Blends of Aromatic Polyethers Bearing Polar Pyridine Units and Their Evaluation as High Temperature Polymer Electrolytes

Aromatic polyethers containing polar pyridine units in the main chain have been synthesized using different difluoride monomers. Copolymers of 2,5-(4′,4″dihydroxy biphenyl)-pyridine and 3,3′,5,5′-tetramethyl-[1,1′-biphenyl]-4,4′-diol with bis(4-fluorophenyl) sulfone or phenyl phosphine oxide difluoride or decafluorobiphenyl (PTMPySF, PTMPyPO, PTMPyDF) were synthesized. These polymeric structures despite their common structural characteristics, showed totally different behavior in terms of solubility and acid doping ability. Blends of these copolymers have been prepared in order to be evaluated in terms of fuel cell relevant parameters like acid doping ability and conductivity. In most cases flexible membranes were obtained by solution casting. The acid doping ability was controlled based on the blend constituents and composition. The doped membranes exhibited high conductivity values, in the range of 10⁻³ S/cm at room temperature which is increased at 2.5 × 10⁻² S/cm at temperatures up to 180 °C.     

空间微弱电磁场的测试、屏蔽及应用

分析了空间电磁干扰对电镜等电子仪器的影响;讨论了电磁屏蔽的设计和空间磁场测试原理;采用自行设计的线包和微弱电磁场测试技术,分析实测了多家实验室,证明该方法简便易行;对检测输电线路的老化和微弱漏电也具有实际意义．     

运动介质的色散关系及等效折射率

结合运动介质本构关系,运用并矢代数方法,求解运动介质中电磁场的色散关系．结果表明,波数k与波频ω之间仍然保持线性关系,其比例系数决定于波传播方向k与介质运动方向v之间的夹角θ、参考系之间的相对运动速度口以及静止介质折射率n’的大小．