LABVIEW下冲击试验测试信号分析模块的设计

根据GJB冲击环境试验测试要求,介绍LABVIEW平台下两类典型冲击信号分析模块的设计方法,主要讲述利用多图层叠加编程技术实现GJB150.18-1986标准规定的半正弦波与后峰锯齿波动态套容差曲线分析模块的设计以及利用递归算法实现冲击响应谱分析模块的设计。其次,采用资源DLL封装技术对LABVIEW编程实现的冲击信号分析模块进行封装,在其他编程语言中调用DLL实现冲击信号分析模块在其他编程语言中的功能链接。实践表明,LABVIEW图形化编程技术可快速实现两类冲击信号分析模块的设计,将高速数据采集模块与冲击信号分析模块集成,可有效完成冲击试验测试与信号分析处理任务。     

Effect of aperture field distribution on the maximum radiated power at atmospheric pressure

The air breakdown in the high-power antenna near-field region limits the enhancement of the radiated power. A model coupling the field equivalent principle and the electron number density equation is presented to study the breakdown process in the near-field region of the circular aperture antenna at atmospheric pressure. Simulation results show that, although the electric field in the near-field region is nonuniform, the electron diffusion has small influence on the breakdown process when the initial electron number density is uniform in space. The field magnitude distribution on the aperture plays an important role in the maximum radiated power above which the air breakdown occurs. The maximum radiated power also depends on the phase difference of the fields at the center and edge of the aperture, especially for the uniform field magnitude distribution.     

Regional and modular expression of morphogenetic factors in the demosponge Lubomirskia baicalensis

Some sponges [phylum Porifera], e.g. the demosponges Lubomirskia baicalensis or Axinella polypoides, show an arborescent growth form. In the freshwater sponge L. baicalensis this morphotype is seen mostly in depths below 4m while in more shallow regions it grows as a crust. The different growth forms are determined in nature very likely by water current and/or light. The branches of this species are composed of modules, arranged along the apical-basal axis. The modules are delimited by a precise architecture of the spicule bundles; longitudinal bundles originate from the apex of the earlier module, while at the basis of each module these bundles are cross-linked by traverse bundles under formation of annuli. Genes encoding putative morphogenetic factors, myotrophin and epidermal growth factor (EGF)-like molecules, and one gene of an antagonist for the Wnt signaling pathway, the soluble frizzled molecule, have been identified and characterized. Their expression levels as well as those of silicatein, one major spicule-forming molecule, have been studied in the crusts and the modules. The data revealed that at the apices of each module higher level of expression of myotrophin and EGF can be detected, while the base of each module is characterized by a high steady-state expression level of soluble frizzled molecule. These results suggest that module formation in L. baicalensis is controlled by a tuned interaction of agonistic (e.g., myotrophin and EGF) as well as antagonistic morphogenetic factors (e.g., soluble frizzled molecule).     

双面太阳能组件辐照度模型的优化

为有效分析固定倾斜安装的多排双面太阳能组件背面辐照度,通过视觉因子辐照度模型分析,将行间距为D的地面划分为n段,并区分阴影区和非阴影区,经过对地面接收散射辐照度的视觉因子,及各电池接收地面反射视觉因子的修正,实现了组件背面辐照度模型改进.模拟与实验结果表明:在某晴朗天气下,倾斜角为26°,离地高度为1.5 m,行间距为...     

基于HART协议的二线制涡轮流量变送器的开发

以HART协议为通信标准,提出了系统的总体方案设计,通过对HART协议的理解与掌握,详细的给出了基于涡轮流量变送器的软硬件设计;硬件设计部分包括涡轮脉冲采集模块,微处理器模块,HART通信模块和4~20 mA环路电流模块4个模块,其中HART通信模块采用HART调制解调器芯片AD5700实现,4~20 mA环路电流模块采用环路供电专用芯片AD5421实现,二者共同构成了HART协议的物理层接口,文章硬件电路所采用的都是低功耗芯片,用纯硬件的方法解决了HART总线设备的低功耗难点;软件设计部分包括主监控程序、变送计算程序和HART协议通信程序3个程序模块,重点讲述了HART协议的数据链路层和应用层的实现过程;最后文章对涡轮流量变送器的二线制传输功能和HART通信功能进行了测试;测试结果表明,变送器的设计要求基本实现了。     

Two-dimensional simulation of polysilicon etching with chlorine ina high density plasma reactor

A two-dimensional fluid simulation of polysilicon etching with chlorine in an inductively-coupled high density plasma source is presented. A modular approach was used to couple in a self-consistent manner the disparate time scales of plasma and neutral species transport. This way, complex plasma chemical reactions (involving electrons, ions and neutrals) as well as surface chemistry can be included in the simulation, The power deposited into the plasma was calculated by an electromagnetics module which solves Maxwell's equations. The power deposition was used in the electron energy module to find the electron temperature and the rate coefficients of electron-impact reactions. These were in turn used as source terms in separate neutral and charged species transport modules. By iterating among the modules, a self-consistent solution was obtained. Quantities of interest, such as power deposition, species density and flux, and etch rate and uniformity were thus calculated, As power deposition was increased, the electron density increased linearly, the plasma became less electronegative, the degree of gas dissociation increased, and the plasma potential remained constant. The radial uniformity of the Cl atom flux was better than that of the ion flux. The reactivity of the wafer as compared to that of the surrounding electrode surface significantly affected the etch uniformity, despite the low pressure of 10 mtorr     

Evaluation of influence of anisotropic diffusion near a wall in near-field fluorescence correlation spectroscopy of nanoparticles

Fluorescence correlation spectroscopy (FCS) of colloidal nanoparticles using a near-field fiber probe was numerically simulated. The near-wall dynamics was simulated by accounting for the anisotropic mobility of nanoparticles owing to hydrodynamic interaction with a wall (Stokes viscous force). By comparing the simulation results with theoretical model calculations, we found that the influence of anisotropic diffusion is insignificant in near-field FCS autocorrelation analysis.     

Design and electrical characteristics of a modular plasma torch

A modular system for constructing an atmospheric pressure plasma source is presented and studied. The design and construction of the plasma torch module by modifying and reassembling the structural components of two different models of spark plugs are first described. Each module can produce a torch plasma of 1 cm radius and 6 cm height and having a peak density exceeding 10¹³ cm^-3. A set of modules, each connected in series with a ballasting capacitor in the circuit, can be operated as an array sharing a common power source to produce a dense and large-volume plasma. The electrical characteristics of the module are studied for the case of a single module and two capacitively coupled modules. The discharge can be maintained, with the aid of ballasting capacitors, in a stable diffuse arc. Furthermore, the coupled discharges in an array of modules are operated with the maximum power efficiency as indicated by a near one power factor seen by the power line     

Inverse Problems of the Near-Field Radiothermometry

It is shown that the one-dimensional problem of near-field microwave radiometry in the case of a smoothly inhomogeneous medium can be reduced to an integral equation similar to the well-known solution of the radiation transfer equation. The kernel of this integral equation depends on only one parameter determined experimentally. This makes it possible to determine the subsurface temperature profiles by using a set of near-field antennas of arbitrary design for which the sounding-depth range is overlapped by the effective depth of formation of the radiation received by these antennas. In the case of near-field measurements, the previously obtained joint solution of the radiation transfer equation and the thermal diffusion equation can also be modified and applied for monitoring the subsurface temperature profile using the temporal dependence of the received signal.     

The optical module of Baikal-GVD

In April 2015, the first cluster of Baikal-GVD was deployed in Lake Baikal and put into operation. It comprises eight strings. Each string consists of 24 optical modules. An optical module is a detection element of Baikal-GVD; it includes a Hamamatsu R7081-100 photomultiplier tube with a high quantum sensitivity. We describe the design of the optical module, the front-end electronics, and the laboratory characterization and calibration.     

声纳湿端数据远传DWDM光电交换模块设计

声纳的应用极其广泛,海洋渔业以及军事应用使得声纳技术得到了大力发展。声纳湿端数据传输的可靠性、实时性是声纳系统性能得到保障的前提。为此设计一用于声纳湿端数据远传的DWDM光电交换模块。在该模块中,使用以太网交换芯片和两个DWDM光模块对数据进行多路转发并实现光通路的冗余备份,提升了系统可靠性的同时使网络拓扑更为灵活。由于DWDM光模块可将电信号转换为波长可选定的光信号,故通过若干该模块协同使用,可实现多路光信号复用即同时传输多条声纳水下阵缆的数据。经实际开发与测试,该模块以太网业务性能指标符合设计需求,且该模块已在某声纳工程项目中得到了应用,并可为其他领域数据远传工程应用提供设计参考。     

Two-dimensional Compact Perfect Shuffle Optical Interconnection

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Simultaneous measurements of the release of atomic sodium, particle diameter and particle temperature for a single burning coal particle

The temporal history of the release of volatile alkali species during coal combustion is a significant, but poorly understood factor in the fouling and corrosion of heat transfer surfaces within industrial coal-fired boilers. We present new results of the simultaneous measurement of particle temperature, particle size and the atomic sodium concentration in the plume of a burning coal particle. During the char phase, the sodium concentration in the plume was found to be linearly dependent on the inverse of particle diameter, but during the ash phase the sodium concentration was found to decay exponentially with decreasing particle temperature. The centreline decay of Na within the plume above the burning particle consists of one region controlled by a first order chemical reaction and a second region controlled by diffusion.     

Quantum Circuit Realization of Morphological Gradient for Quantum Grayscale Image

In this paper, based on the principle of classical morphology operations, the flat grayscale dilation and erosion operations are proposed for NEQR quantum image model. Furthermore, through combining these two morphology operations, we further realize the morphological gradient operation. As the basis of designing of grayscale morphology operations, a series of quantum circuit designs arepresented, which includes special add one operation UA₁(n) and special subtract one operation US₁(n) both for an n-length qubits sequence, quantum unitary operation U_C, parallel subtractor (PS) module, quantum comparator output the large QCOL and quantum comparator output the small QCOS modules. When designsthe concrete quantum circuit, a sequence of UA₁(n) and US₁(n) modules are used to obtain the quantum image sets based on the shape of specific structuring element. Then, the searching for maximaor minima in a certain space is involved, which can be solved by cascading a series of QCOL and QCOS modules in certain order. Finally, the PS module can be used to calculate the difference of the maxima and minima for producing the morphological gradient. The circuit’s complexity analysis illustrate that our scheme is very lower to the classical morphology operations.

     

Optimization of ultrathin carbon film coated silver nanoshell for biomedical applications in vivo

The extinction spectroscopy and near-field enhancement of dielectric-silver nanoshell coated by tetrahedral amorphous carbon [ta-C] layer (DSC) have been calculated by using Mie theory. With decreasing the Ag layer thickness, the localized surface plasmon resonance (LSPR) of DSC nanoshell moves from the visible region into the near-infrared region and the corresponding local field factor (LFF) increases first and then decreases. In addition, the increase of ta-C shell thickness leads to red-shift of LSPR and the decrease of LFF in DSC nanoshell. We further find that the increase of the dielectric constant for the outer shell can induce a significant enhancement of near-field. Based on the simulation analysis, we show that the DSC nanoshell can provide strong near-field in near-infrared region and may be suitable for the biomedical applications in vivo.     

Computational study of lean premixed turbulent flames using RANSPDF and LESPDF methods

A computational study is performed on a series of four piloted, lean, premixed turbulent jet flames. These flames use the Sydney Piloted Premixed Jet Burner (PPJB), and with jet velocities of 50, 100, 150 and 200 m/s are denoted PM150, PM1100, PM1150 and PM1200, respectively. Calculations are performed using the RANSPDF and LESPDF methodologies, with different treatments of molecular diffusion, with detailed chemistry and flamelet-based chemistry modelling, and using different imposed boundary conditions. The sensitivities of the calculations to these different aspects of the modelling are compared and discussed. Comparisons are made to experimental data and to previously-performed calculations. It is found that, given suitable boundary conditions and treatment of molecular diffusion, excellent agreement between the calculations and experimental measurements of the mean and variance fields can be achieved for PM150 and PM1100. The application of a recently developed implementation of molecular diffusion results in a large improvement in the computed variance fields in the LESPDF calculations. The inclusion of differential diffusion in the LESPDF calculations provides insight on the behaviour in the near-field region of the jet, but its effects are found to be confined to this region and to the species CO, OH and H₂. A major discrepancy observed in many previous calculations of these flames is an overprediction of reaction progress in PM1150 and PM1200, and this discrepancy is also observed in the LESPDF calculations; however, a parametric study of the LESPDF mixing model reveals that, with a sufficiently large mixing frequency, calculations of these two flames are capable of yielding improved reaction progress in good qualitative agreement with the mean and RMS scalar measurements up to an x/D of 30. Lastly, the merits of each computational methodology are discussed in light of their computational costs.     

Mapping an on-chip terahertz antenna by a scanning near-field probe and a fixed field-effect transistor

In the terahertz(THz) regime,the active region for a solid-state detector usually needs to be implemented accurately in the near-field region of an on-chip antenna.Mapping of the near-field strength could allow for rapid verification and optimization of new antenna/detector designs.Here,we report a proof-of-concept experiment in which the field mapping is realized by a scanning metallic probe and a fixed AlGaN/GaN field-effect transistor.Experiment results agree well with the electromagnetic-wave simulations.The results also suggest a field-effect THz detector combined with a probe tip could serve as a high sensitivity THz near-field sensor.     

Near-field properties of diffraction through a circular subwavelength-size aperture

Analytical nonparaxial vectorial electric field expressions for both Gaussian beams and plane waves diffracted through a circular aperture are derived by using the vector plane angular spectrum method for the first time,which is suitable for the subwavelength aperture and the near-field region.The transverse properties of intensity distributions and their evolutions with the propagating distance,and the power transmission functions for diffracted fields containing the whole field,the evanescent field and the propagating field are investigated in detail,which is helpful for understanding the relationship between evanescent and propagating components in the near-field region and can be applied to apertured near-field scanning optical microscopy.     

航空电子设备自动测试系统的软件架构设计

为检测和定位航空电子设备的故障,研究并设计了一种自动测试系统的软件架构;该架构包含了测试软件和测试数据库,测试数据库存储有测试被测设备的相关数据,测试软件将其作为输入,通过自动测试设备输送给被测设备,最终测试软件接收被测设备的输出并将其与测试数据库的预期数据相比较得出测试的结果;测试软件由手动测试模块、自动测试模块、系统自检测模块、测试记录读取和测试结果记录模块4个功能模块组成,自动测试和手动测试可以自由切换;该系统不仅能使用自动测试功能仿真被测设备的飞行环境,还可以使用手动测试功能具体定位分析故障,降低了设备的维护成本,缩短了维修时间。     

The use of X-ray photoelectron spectroscopy in corrosion science

Most metals in commercial use are protected from reaction with an environment at ambient temperature by an oxide layer of ~5 nm in thickness. This layer may increase in thickness, by solid state diffusion, at high (>300°C) temperature or may dissolve and be replaced by soluble species by electrochemical reactions in aqueous environments. These are the twin processes of corrosion and the problem of preventing such destructive transformations had led to a longstanding interest by corrosion scientists in the thin film: and indeed in sub-monolayers. Prior to the introduction of the techniques of surface derived ion and electron spectroscopy the chemical analyses of films, which had known physical and electronic characteristics, were unavailable. This review attempts to specify the requirements of an analytical technique for thin films and examines the present role of XPS in this context. The areas covered will include elemental analysis, evaluation of valence state, non-destructive information, elemental distribution and finally the use of ion-etch depth profiling. Examples are drawn from corrosion problems in both aqueous and gaseous environments.