Account of Thermal Flow Through Metal-Semimetal BiSb Contact Boundary for Determination of EHF Detector Volt-Watt Sensitivity

Bismuth, antimony and its alloys are the typical representatives of a class of semimetals, which electric conductance is lower in 10²-10³ times, than of usual well conducting an electrical current metals. The alloys bismuth with antimony have semi-conductor properties in wide area of compositions at temperatures below 77 °K. The semimetals are rather perspective materials from the point of view of their probable application in various devices [1,2,3].In present time the semimetal alloys BiSb have wide application in thermoelectric generators and refrigerators. In work [3] the opportunity of use of semimetals BiSb with percentage content of Bi and Sb from 8 % up to 25 % was shown as high-sensitivity and of small inertion indicators of the mm range radiation where thermoelectric effect is used. The principle of action of such indicators is based on occurrence of temperature gradient in a semimetal crystal BiSb that has two contacts of the various area with flowing electrical current. Basic element of such device is the dot contact metal - semimetal. One of the main characteristics is volt-watt sensitivity of metal-semimetal BiSb contact which calculating is shown in present work.     

Metal-Monocrystal BiSb Point Contact Detector for MM Wave Range

The paper presents the experimental results on thermoelectric detectors with the metal-semimetal BiSb point contact in the 8-mm wave range. The volt-watt sensitivity and response rate have been determined.     

Balanced Parametric Amplifier of the MM Range

Results of research of balanced circuit of noncooled input parametric amplifier for 60 – 65 GHz band are given in this work. Elektrodynamics characteristics of oscillatory system in which there were used waveguide converters of H ₁₀-wave into H ₂₀ based on angle inhomogeneous are studied. The experimental results of research of amplifier models that based on BSD without package are shown. Amplification factor is 10–15 dB; noise temperature is 400 - 500 ⁰K.     

传感器几何结构对近红外组织氧合检测仪灵敏度的影响

近红外组织氧合检测仪基于强散射条件下修正的朗伯－比耳吸收定律,通过连续记录多个近红外波长下光密度随生理状态的变化,从而可达到对人体组织中光的吸收体（氧合血红蛋白,还原血红蛋白,细胞色素氧化酶等）浓度变化的定量检测。本文利用蒙特卡罗仿真方法对光在多层生物组织模型中的平均穿透深度、光子平均飞行距离和空间灵敏度分布进行了仿真,结果表明,传感器几何结构,即光源与光检测器之间的距离是影响检测灵敏度的重要因素     

耦合形貌对Si4团簇电子输运影响的第一性原理计算

运用密度泛函理论与非平衡格林函数相结合的方法,对Si₄团簇与Au （100）-3×3两电极以顶位-顶位、顶位-空位、空位-空位三种形貌相连构成的Au-Si₄-Au纳米结点的拉伸过程进行第一性原理模拟,计算不同构型纳米结点在不同距离的电导和结合能.讨论耦合形貌、距离对结点电导的影响,结合能的计算表明三种不同耦合形貌结点存在稳定平衡结构,其平衡电导分别为0.71 G₀、0.96 G₀和2.44 G₀,且在-1.2 V~1.2 V的电压范围内,三种不同耦合形貌结点稳定结构表现出类似金属的导电特性,其I-V关系都近似为直线.计算结果表明Si₄团簇与电极的耦合形貌、两极距离对纳米结点电子输运有重要影响.     

Effects of Contact Geometry on Electron Transport of 1,4-Diaminobenzene

The equilibrium electron transport of 1,4-diaminobenzene sandwiched between two Au electrodes is simulated by using a first principles analysis. The results show that equilibrium conductance increases with the molecule- electrode distance decreasing, and a platform occurs at the distance varying from 1.4 A to 1.9 A, implying the insensitiveness of 1,4-diaminobenzene equilibrium conductance to molecule-electrode distance. This is helpful to understand the improved reliability and reproducibility of conductance measurements using amines.     

单层SbAs和BiSb的表面修饰调控

基于密度泛函理论的第一性原理计算,研究了V族二维层状材料SbAs和BiSb在全氢化和全氟化后体系的晶体结构、稳定性和电子结构.计算结果表明,全氢化后SbAs和BiSb由buckled结构转变为准平面结构,而全氟化后则转变为low-buckled结构.同时,本征、全氢化和全氟化的SbAs和BiSb均具有很好的稳定性,具备实验合成的可能性.电子结构的分析表明,全氢化和全氟化后SbAs和BiSb均由宽带隙半导体转变为窄带隙的直隙半导体,且其能带结构仍具有很好的线性色散.通过对准平面和low-buckled结构SbAs和BiSb电子结构的进一步分析,揭示了全氢化和全氟化后体系能带变化的原因.在h-BN衬底上的计算结果显示,由于两者间的弱耦合作用,使得全氢化和全氟化SbAs的直隙半导体特征得以保留,表明其在未来光电子设备等领域中具有广泛的应用前景.     

Sensitivity Analysis of Contact Type Vibration Measuring Sensors

With the Internet of Things (IoT) era dawning in, we are surrounded by a plethora of sensors. The present paper focuses on MEMS-based vibration measuring accelerometers, which are ubiquitously present in smartphones, tablets, smartwatches/bands, etc. These contact type vibration sensors have the unique advantage of being very small, low cost, low power, less weighing, and easily accommodatable in electronics. However, the accuracy of these sensors needs to be quantified with respect to more accurate sensors. With this objective, the paper presents a comparison of the relative sensitivity of a MEMS-based accelerometer (MPU 6050), a Geophone, and a sensor from Xiaomi Y2 smartphone with respect to a more standard Piezoelectric ICP based accelerometer, when all sensors are tested on a shaker table. Data are measured with harmonic excitation over a frequency range of 2–184 Hz. The relative sensitivity of MPU 6050 was 90% accurate in the frequency range 18–116 Hz for RMS measurements. Other sensors such as the one used in the Xiaomi Y2 smartphone and the Geophone were less accurate. The relative sensitivity measured in this work can be used to obtain sensitivity and hence more accurate data from these low-cost accelerometers.     

Influence of Template Geometry on Polymer Micro-Structure Duplication in Electrohydrodynamics Patterning Process

Electrohydrodynamics patterning is a process for electrically duplicating micro–nano patterns on polymer films by applying an electrical field. An investigation into the hydraulic behavior of the polymer as affected by the template-modulated electrical field is critical for understanding the process capability and template design. A coupling model is presented to characterize the influence of template geometry on the pattern duplication. The transient simulation is carried out to study the formation of a pattern. It is proposed that the electrical field modulated by the template can be divided into a spatially nonhomogeneous component which generates the periodic pillars undesirably and a spatially nonhomogeneous component which generates a duplication of the template pattern as desired. We find that the template geometry has a significant effect on the template-modulated electrohydrodynamics. A high-fidelity duplication of pattern is better suited to a low projection ratio, a decreased template spacer height, and an increased pattern aspect ratio.     

有机玻璃的几何形状对爆炸切割影响的研究

为了改善现有的航空弹射救生系统,提高飞行员安全逃生的成功率,提出了微爆索切割技术在航空穿盖弹射救生系统中的应用。采用非线性动力显式程序LS-DYNA3D,对有机玻璃平板元件、航空舱盖的微爆索切割过程进行了数值计算分析,得到了不同装药量下有机玻璃平板元件、航空舱盖的切割深度,对比了有机玻璃的几何形状对微爆索切割深度的影响。模拟结果表明:有机玻璃平板切割实验对航空舱盖切割实验具有一定的指导意义,研究结果也可为微爆索线性切割航空舱盖的实验设计提供依据。     

内螺纹管管型结构对管内流动阻力特性的影响

对不同结构的内螺纹管内空气-水两相流动的阻力特性进行了实验研究,从实验方面得出了影响内螺纹管阻力特性的主要几何参数(螺纹高度,螺纹升角,螺纹宽度等)对内螺纹管阻力特性的影响规律。结合实验现象,引入了研究内螺纹管阻力特性的并联管路模型,最终得出适用于不同结构内螺纹管的阻力特性半理论经验公式。通过该公式可以较好地反映出各个几何参数对内螺纹管阻力特性的影响规律。     

Study on Increasing Measurement Range and Enhancing Sensitivity of PCF Surface-Plasmon-Resonance Biosensor using Black Phosphorus

Journal of Russian Laser Research - We propose a quasi-D-shaped photonic-crystal-fiber surface-plasmon-resonance (PCF-SPR) biosensor based on ultrashort side polishing. The gold film layer of the...     

Influence of Surface Geometry of Grating Substrate on Director in Nematic Liquid Crystal Cell

The director in nematic liquid crystal cell with a weak anchoring grating substrate and a strong anchoring planar substrate is relative to the coordinates x and z. The influence of the surface geometry of the grating substrate in the cell on the director profile is numerically simulated using the two-dimensional finite-difference iterative method under the condition of one elastic constant approximation and zero driven voltage. The deepness of groove and the cell gap affect the distribution of director. For the relatively shallow groove and the relatively thick cell gap, the director is only dependent on the coordinate z. For the relatively deep groove and the relatively thin cell gap, the director must be dependent on the two coordinates x and z because of the increased elastic strain energy induced by the grating surface.     

微槽群内汽泡动力学行为对接触线的影响

针对沸腾情形下毛细微槽群热沉内汽泡对汽液固三相接触线的影响,进行了可视化实验研究。研究结果表明：汽泡动力学行为会直接导致微槽群内三相接触线的形状变化,从而引起蒸发薄液膜的厚度、面积以及汽液界面曲率等对薄液膜的蒸发换热特性有重要影响的物理量的变化。实验证实了在开放式微细尺度槽群结构热沉中,固有弯月面区域里的沸腾与扩展弯月...     

光源线宽对内置式光纤法布里-珀罗磁场传感器灵敏度影响的分析

分析了内置式光纤法布里－珀罗磁场传感器的灵敏度及光源线宽对灵敏度的影响。结果表明,光源线宽愈窄,灵敏度愈高;法布里－珀罗腔的反射率在红宽和腔长一定时,有一最佳值。反射率取最佳值时,探测的磁场最小,灵敏度最高。     

Fredholm Modules on P.C.F. Self-Similar Fractals and Their Conformal Geometry

The aim of the present work is to show how, using the differential calculus associated to Dirichlet forms, it is possible to construct non-trivial Fredholm modules on post critically finite fractals by regular harmonic structures (D, r). The modules are (d _S , ∞)–summable, the summability exponent d _S coinciding with the spectral dimension of the generalized Laplacian operator associated with (D, r). The characteristic tools of the noncommutative infinitesimal calculus allow to define a d _S -energy functional which is shown to be a self-similar conformal invariant. Thiswork has been supported by the project “Teoria ellittica e forme di Dirichlet su spazi frattali” G.N.A.M.P.A. 2008 and by the G.R.E.F.I.-G.E.N.C.O. French-Italian Research Group.     

Modeling of Influence of Helix Geometry on the Constitutive Parameters of the Chiral Medium

Computations are made to estimate the influence of geometry of the helixes in an artificial chiral medium made by embedding small conducting helives in a lossy isotropic host material on the three constitutive parameters of the medium, by using a proposed model which explicitly includes the first-order effects of reradiation from the helixes, near-field loses and mutual coupling between helixes.     

光折变晶体几何结构对自泵浦相位共轭特性影响的研究

基于Cu∶KNSBN晶体的自泵浦相位共轭实验,研究了光折变晶体的几何结构对自泵浦相位共轭特性的影响,得到在入射角不变的情况下,随着入射位置的变化相位共轭光输出有最大值,几何结构不同最大值输出对应的位置不同.并从理论上分析了晶体结构在双作用区自泵浦相位共轭机制中的作用,指出几何结构、入射位置与自泵浦光通道、耦合系数的关系及在自泵浦相位共轭效应中存在一个最佳入射光工作位置.     

Volt-Watt Sensitivity of Semimetal BiSb Film Thermocouple Sensors in the 8 mm Wavelength Range

The paper considers the experimental and analytical data on volt-watt characteristics of metal-semimetal BiSb film point contacts in 8 millimeter wavelength range. Analytical expressions have been obtained for the volt-watt sensitivity and the resistance of the metal-semimetal BiSb film point contacts. A thermoelectric millimeter wave range detector has been designed on the basis of the sensors; the performance is illustrated by experimentally determined volt-watt relations.