机械阻抗测量的一种新方法

本文介绍了一种新的机械阻抗测量方法－声强法，由定义出发将机械阻抗表为功率流和加速度响应谱的函数，应用结构声强技术测量功率流，声强法不需要测量作用力信号，可以用于测量任意结构中的各类机械阻抗，实验结果表明，声强获得的测量值与直接获得的测量值相近，声强法能较准确地测量一维和二维匀质结构中机械阻抗。     

Optical-heterodyne method for measuring surface strain

A new form of optical heterodyne method for measuring surface strain is proposed. In this method we detect the phase difference between two beat signals obtained from the light waves scattered by two neighboring points on a rough surface. Each of the two points is illuminated by two laser beams with different frequencies: totally there are four laser beams. The detected beat signals which are obtained at the two points have different phases. This phase difference is measured by an electrical circuit. The deviation of the measured phase difference is proportional to the difference of displacement at the two points: that is surface strain. Strains of a thin plate have been measured as a verification experiment. The experiment confirmed the theory for 10^-4 to 10^-5 strain.     

相对法测量表面张力系数

从细管缓慢流出的液体,并不是呈现连续的液流,而是一些继续的液滴。通过对不同液体液滴大小的比较,可测得表面张力系数。     

极大值法测量表面张力系数

测量金属薄片从液体中拉出过程中液膜高度和拉力的关系,分析其产生的原因,给出液体表面张力系数的准确测量方案.     

On the theory of surface impedance of metals placed in a magnetic field

The smooth non-monotonous dependence of the metal surface impedance upon the magnetic field H is investigated theoretically for the cases of diffuse and specular reflection of electrons from the specimen boundary. The type of the electron-surface interaction has been found to have very little effect on the magnitude of the impedance Z_α(H) in the range of weak magnetic fields [equation (1)]. In a strong field [equation (2)] the surface impedance behaves differently for diffuse and specular reflection. The form of the Z_α(H) function depends essentially on the ratio of the electromagnetic wave frequency ω and the collision frequency of electrons ν. This provides a possibility of establishing experimentally the frequency of electron collisions with volume scatterers.     

A direct method for measuring acoustic ground impedance in long-range propagation experiments

A method is reported for determining ground impedance in long-range propagation experiments by using the definition of impedance directly. The method is envisioned as way of measuring the impedence at multiple locations along the propagation path, using the signals broadcast during the experiment itself. In a short-range (10 m) test, the direct method was in good agreement with a more conventional model-based least-squares method. The utility of the direct method was demonstrated in a 400 m propagation experiment in a agricultural field. The resulting impedance was consistent with the impedance measured previously in the same field.     

An impulse method of measuring normal impedance at oblique incidence

An experimental method of determining the oblique incidence behaviour of sound absorbing materials is given. The method involves the measurement of acoustic impulses at the surface of an absorbing material and comparing the complex frequency components with those of a reference signal recorded remote from the surface. Amplitude and phase characteristics of the reflected signal are thus obtained and hence the normal impedance of the material is found. Comparison between measurements made by the “surface” method and standing wave tube measurements shows good agreement for normal incidence. However, at very oblique angles of incidence the method is in obvious error, the accuracy being limited by a sphericity effect.     

Optical method for measuring the coupling constant of surface acoustic waves

The coupling constant of common or thin-layered-piezoelectric interdigital transducers for surface acoustic waves up to the highest frequencies can be determined in an optical way with reproducibility better than 3%. Being a nondestructive and noncontact method one can apply it in the technological process for fabricating uniform piezoelectric layered transducers.     

一种检测减影(DSA)图像中肺癌肿瘤大小的新方法

当肺癌被胸水淹没时 ,无法用常规X胸片测量肺癌肿瘤的大小。提出了采用形态算子滤波和广义模糊算子 (GFO)检测边缘 ,从而获得支气管动脉减影图中的肺癌肿瘤的边缘轮廓 ,进而计算得到肿瘤的大小。该方法为肺癌介入病人提供了一种新的肿瘤检测手段 ,且拓展了数学形态学和广义模糊算子的应用领域 ,具有一定的的实用价值和理论价值。     

Optical method for measuring the amplitude response of surface acoustic wave devices

The amplitude response of acoustic surface wave (SAW) devices up to the highest frequencies can be determined in an optical way without electric shielding. This makes it possible to use the method for fast nondestructive testing and control in SAW-device production as well.     

Role of specular reflection of electrons in the radio frequency surface magneto impedance of metals

The effect of a parallel magnetic field on the 10-mHz surface resistance of gallium single crystals is reported. We suggest that the observed structure can be interpreted in terms of an angular dependence of the probability of specular reflection of the electron at the crystal surface. This model allows a quantitative determination from the data of the temperature-dependent electron mean free path for electron wave vectors with a narrow range that is determined by the magnetic field and crystal orientation.     

Density-functional method for surface properties of two-component plasmas of liquid metals

A general density-functional formalism for an inhomogeneous two-component liquid metal is described. The expression for the free energy is obtained and the gradient approximation is used for its simplification. Both electronic and ionic gradients are present in the theory.     

探讨测量液体表面张力系数的优化方法

针对用拉脱法测液体表面张力系数的系统误差较大的系列问题,提出了自动降拉双π丝补偿法.用自动化降拉代替手动提拉,提高了操作过程的稳定性;用双π丝代替π丝,消除了拉膜丝的不光滑点;用突变初态和补偿态作为测量状态,有效地排除了浮力、膜重以及侧丝上的表面张力对实验结果的影响.自动降拉双π丝补偿法得到的实验结果,其精度比拉脱法提高3%.     

金刚石刀具nm级表面轮廓质量多参数集成测量方法

为有效解决金刚石刀具表面轮廓质量评价指标分散、无法进行全面系统测量的难题,基于原子力显微镜和超精密回转轴系,提出了实现前后刀面粗糙度、刃口锋利度和刃口微豁三个关键指标的集成测量方法。根据金刚石刀具表面轮廓质量的测量要求,以原子力显微镜扫描系统、气浮隔振平台、二维移动平台以及精密回转轴系为基础构建测量系统,精确测量了金刚石刀具刃口附近的表面微观形貌;采用基于MATLAB开发的专用测量软件对原始数据进行处理,得到金刚石刀具前后刀面粗糙度值、刃口锋利度值和刃口微豁范围;并对测量误差进行了分析,提出了控制要求。通过上述自主开发的测量仪器,可以高效、完整地描述金刚石刀具表面轮廓质量,能够实现nm级粗糙度、亚m级锋利度以及m级微豁的准确测量。     

测量钢化玻璃表层应力的漏波导方法

本文报道利用漏波导方法测量钢化玻璃的表层应力。通过基模的双折射引入有效表层应力,并制作出相应的测量装置。对风冷钢化、化学钢化和慢退火玻璃,测量了有效表层应力,并在理论上分析了测量精度。     

一种激光雷达测量海洋光学参数的新方法

为了拓展海洋光学参数的激光遥感测量手段,借鉴高光谱分辨率多普勒激光雷达对大气散射信号的测量机制,提出了一种利用激光雷达水下后向散射信号测量海洋固有光学参数的新方法。在原理方面,描述了测量系统的组成和利用碘分子吸收滤波器实现水分子瑞利散射信号和悬浮物米散射信号的光谱分离测量方法, 在结论方面,给出了利用海水激光后向散射信号实现海水悬浮物后向散射系数和海水体消光系数的具体反演算法。     

测量精磨玻璃表面破坏层深度的侧面观测法

本文主要介绍用侧面观测法测量精磨玻璃表面破坏层深度的试件制做、测试仪器；对精磨裂纹也做了一定的分析。