长距离管线监测系统的一种智能化过流防护方法

介绍了长距离管线监测系统的一种智能化过流防护方法，详细说明其电路设计原理及相关元件的选择，并与串联自复过流保护元件方式相比较，分析其整体性能，说明其具有响应速度快，安全可靠等特点。     

平面近场测试系统在天线测试和诊断中的应用

介绍了天线近场测量的基本原理和HD-1型平面近场测试系统,并对近场测量在实际天线测试中的应用情况、发展方向和应用前景等作了简单的描述。     

一种在Kalman滤波中引入径向速度测量的新方法

研究在距离和径向速度测量噪声统计相关的情形下把径向速度测量引入Kalman滤波的新方法。分析了径向速度测量噪声与位置测量更新后状态滤波误差的统计相关性,根据Gauss-Markov定理导出了对应于径向速度测量的滤波方程由此而得到一种序贯滤波算法。两个不同的蒙特卡罗仿真表明,通过采用这一新算法引人径向速度测量,不仅可以大大提高状态估计的精度,而且其估计性能和计算效率优于传统的EKF。     

Precision equipment for symmetrical bending— Part 1. The loading system

The design and performance of precision bending equipment for testing straight beams with constant rectangular section under a pure bending moment is described. Part 1 deals with the loading arrangements and Part 2 with the rig for measuring beam deflection. The methods for recording deflection of strain gauges applied on the beam have been described elsewhere.^1–4
The reactions to the deadweight gravity loads are taken via ball bearings. The total bending moment inaccuracy, i.e. the sum of estimated systematic errors and random errors, the latter expressed as the 2Ga confidence interval about the mean (2G_cim), is about ± 25 x. 10^-4%, for 23 tests with a steel beam with 15 mm × 75 mm cross sectional dimensions, loaded to 1-1.5 mm/m strain.
The measuring rig stands on the beam via hardened and polished spherical segment feet and uses a capacitive transducer system with less than 5nm resolution. Various application tasks are described. The total inaccuracy of the measured deflection, i.e. apart from bending moment inaccuracy, is about ± 35 times 10^4% for about 10 reproduced, not repeated, tests with the same steel beam. The deflection for such a beam is of the order of 2 to 4 mm.     

Effect of refraction on optical microscopic measurement of internal blood-vessel diameter and its correction

In optical microscopic measurement of internal blood-vessel diameters, the effect of refraction must be taken into account to ensure accuracy of the result. This effect is discussed and an analytical correction formula derived. Phantom blood vessels with known internal and external diameters were used to test the validity of the correction formula. The errors obtained prior to correction were reduced significantly after correction.     

The solution of the inverse problem of gravitational potential using a set of measurements of different field elements

A numerical solution of the inverse problem of the gravitational field at a single point is obtained using six field elements for a point, a spherical cap, a differential spherical sector and a vertical segment. In the system of six equations obtained, the unknowns are the mass of the body, the depth of its center, and the second, third, and fourth degree moments. The accuracy of the solution of this system is ten times higher than when using three field elements. __________ Translated from Izmeritel’naya Tekhnika, No. 5, pp. 3–8, May, 2007.     

Feasibility study of absolute activity measurement with metallic magnetic microcalorimeters

We report on a feasibility study on precise determination of mass-specific activity of low-energy emitting radioisotopes. Conventional methods of activity measurement suffer from source self-absorption and a strong decrease in detection efficiency for low-energy electrons and photons. We propose a new method based on metallic magnetic microcalorimeters with the source embedded in the detector target in a 4π geometry. First results with a ⁵⁵Fe source show that electrons and photons are detected with a detection efficiency close to unity and with little loss of energy for electrons. The aim of this study is to provide standards of activity with very low uncertainties in the framework of radiation metrology.     

10kV配电室操作控制电源电压下降的解决措施

本提出了10kV配电室操作电压下降的现场解决方案。     

纳米颗粒的测量与表征

介绍了用于纳米颗粒测量的电镜观察法、X射线衍射线宽法、激光粒度分析法、比表面积法、颗粒沉降法、扫描探针显微术以及小角X射线散射等,并对其测量原理、测量过程、适用范围及测量方法的优缺点进行了讨论。     

基于Protel DXP的电路仿真设计

Protel DXP是集所有设计工具于一身的电子设计自动化(EDA)软件.文中运用其内嵌的仿真器叙述了分压式偏置电路放大器的仿真设计过程,设计过程简单、方便.在电子线路理论教学过程中引入电路设计仿真环节在不同情况下对电路进行实时分析,不仅可以提高学生的学习兴趣,而且能够在较短时间内加深学生对理论知识的理解;在工程设计过程中利用仿真工具对电路进行即时测试,可以缩短设计周期,提高设计效率.