新型纳米阻抗显微镜前置放大器的设计

基于扫描隧道显微镜的新型纳米阻抗显微镜（STM-NIM）能够测量材料表面的纳米微区阻抗性质并具有分辨率高的突出优点，但传统STM前置放大器的频率带宽不能满足STM-NIM测量模式的要求，因而需要设计新型前置放大器。STM-NIM前置放大器必须在噪声和频率带宽两方面同时具有非常优良的性能。本文利用STM及NIM信号的特点，通过将信号一分为二并对电路进行优化，研制出了满足STM-NIM测量要求的新型前置放大器。测试表明，该前置放大器能同时用于NIM阻抗测量和STM形貌扫描；其NIM信号的频率带宽达到300kHz；其STM信号的噪声约为0．8mV，能满足原子级分辨成像的要求。     

液压回路分析的新方法

四、放大器柱阀本身是一个流量放大器,如果要获得放大的压力信号,则必须将经柱阀放大了的输出流量信号转换成压力信号,一般都采用液阻作为这种转换元件。输出为压力信号的放大器称为压力放大器,或简称放大器。 1.单柱阀放大器     

仪用放大器在气象仪器中的应用

仪用放大器在气象仪器中的应用长春气象仪器研究所徐磊坚仪用放大器通常在多点数据采集、工业自动控制等技术领域对来自传感器的直流缓变信号起放大和缓冲作用，并能提供高精度信号，成为整个系统决定精度的关键部件之在集成运放技术性能日趋理想化的今天，仪用放大器电路...     

一种高效射频离子源的实现方法

针对它激式射频离子源存在体积大、结构复杂、效率低、匹配速度慢的不足，提供一种高效射频离子源的实现方法，可用于电感耦合等离子体质谱仪和光谱仪。该射频离子源由频率信号源产生一定频率的正弦波信号，之后送给信号调理电路，将正弦波信号整形、差分、占空比调节后变成两路相位差为180°的矩形波信号，送给前级放大器放大后再驱动主放大器，输出的大功率信号经阻抗匹配网络加载到负载线圈，通过点火形成射频等离子体。     

一种用于涡街流量计的程控放大器

涡街信号的幅值随频率成平方关系而变化,输出信号幅值的差别很大。为了保证测量精度,要求信号幅值控制在一个合适的范围内。为此,采用数字电位器和低功耗运算放大器研制了一种程控放大器。通过TMS320LF2407A DSP芯片计算涡街信号的绝对平均值来确定和调节放大器的增益,以适应涡街信号幅值的变化。实验结果表明,程控放大器的设计和幅值调整方法是有效的。     

基于MATLAB仿真的锁定放大器的研究

研究了锁定放大器的实现原理,并根据该原理用MATLAB的SIMULINK工具箱对锁定放大器进行了建模和仿真。仿真结果表明锁定放大器具有卓越的微弱信号检测能力。在实际测试中。所设计的锁定放大器也很好的完成了信号的检测和拾取。     

压阻传感器信号调理的解决方案

近几年来，压阻传感器（如硅压力传感器）得到了更为广泛的应用，到目前为止，尚我论文全面地介绍这类应用的解决方案，就目前普遍使用的压阻传感器，给出了一系列全面的传感器信号调理的解决方案，这些设计方案分别基于运算放大器，仪表放大器以及集成一体化的传感器信号调理器等集成电路，分别满足不同档次的产品要求。     

汽车检测线的计算机联网改造(续)

五、测控子系统工作原理１．一工位检测单元工作原理（见图３）（１）当车辆进线检测到达一工位后，引车员按动“位置／报速”信号发生器，经接收器译码后向一工位微机发出到位信号，微机根据一工位检测程序发出相应控控制箱工位微机显示屏音箱右轴重左制动左轴重右制动制动台开关光电信号Ⅱ前置放大器发动机性能等项目检测器控制烟度计或尾气分析仪进行工作，将汽车尾气或烟度等模拟量信号由前置放大器采集和精密放大后，送一工位微机处理。一氧化碳和烟度信号共享一个前置放大器，检测烟度时，微机通过继电器控制电路，变换“选通开关”指…     

全隔离型仪表放大器AD202KY及其应用

简述一种新型隔离仪表放大器ＡＤ２０２ＫＹ的内部结构框图和基本性能参数，重点讨论了该放大器的基本工作原理，介绍了几种具有实际应用价值的全隔离信号放大电路。     

前置放大器NF图的测试方法及装置

前置放大器ＮＦ图的测试方法及装置戴逸松，徐建生，张新发（吉林工业大学长春１３００２５）０引言衡量前置放大器噪声大小的最常用指标是噪声系数Ｆ，或噪声因数ＮＦ（ＮＦ—１０１ＯｇＦ）。因为对微弱信号检测仪器来说，可以检测的最高灵敏度决定于放大器的噪声系数，...     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.