Reactive Power Meter for Nonsinusoidal Systems

This paper describes a novel reactive power meter realized by electronic circuits that determine successively the terms of the equation Q = ?n=1?VrIrsin?r for n significant harmonics. The harmonic contributions to the total reactive power is determined by electronic simulation of the mathematical expression that sets the orthogonal condition of two functions in a periodical interval. Partial reactive power with its sign are stored and added in a circuit to get at the end of the cycle the total reactive power. A control system permits operation in a repetitive form.     

Measurement of the Individual Harmonics Reactive Power in Nonsinusoidal Systems

This paper presents a method of individual harmonics reactive power measurement for a load supplied by a nonsinusoidal source. The method consists of transforming the load-voltage and the load-current frequency spectra by multiplying both quantities by the quadrature voltages. Next, the products obtained are filtered with a pair of mutually symmetrical narrow-band filters. The mean value of the filter output voltage product appears to be proportional to the individual harmonics reactive power of the load.     

Metrological Characterization and Operating Principle Identification of Static Meters for Reactive Energy: An Experimental Approach Under Nonsinusoidal Test Conditions

In this paper, an experimental approach is proposed for the metrological characterization of the static meters for reactive energy and for the individuation of their operating principle in nonsinusoidal conditions. The proposed approach was developed by starting from the only available accuracy test condition in the presence of the harmonics introduced by the standards for active static meters. In this paper, the proposed approach is described, and some experimental tests are presented, which were performed on some meters of different accuracy classes and with both known and unknown operating principles.     

Modifying Cr-Al Coatings by Reactive Element Additions: Eiperimental and Theoretical Considerations

Cr-Al diffusion coatings have been modified by Hf addition using a one step halide activated pack cementation process. The substrate was a low alloy steel 2.25Cr-1 Mo. Cyclic Oxidation properties of the coatings were evaluated, and a Hf modified coating was the most resistant coating. Codeposition pack thermodynamics were computed and analyzed using available thermodynamic tools in order to compare experimentally obtained results with theoretical predictions.     

应对新形势 推进电力企业电能计量创新发展

本文针对电力企业电能管理面临的新形势,分析电能计量工作的基本特点和规律,通过发挥集约化优势,规范电能计量管理和检定.依靠科技进步,保证电能计量装置运行安全和可靠.正确处理技术监督和服务的关系,建立有效的社会和内部监督机制,保障电能计量的科学、准确、公正.推进电力企业电能计量创新,促进电力生产经营的可持续发展.     

Improved Reactive Power Measurement through Precision Phase Angle Determination

In the past, the accuracy of reactive measurement has been substantially limited by the precision with which two voltages in quadrature could be generated. A technique employing a commercially available electronic phasemeter has been developed whereby phase angles may be established very precisely. This technique is described in the context of reactive measurements, and other applications are suggested as well.     

Jackknifing in Unbalanced Situations

Both the standard jackknife and a weighted jackknife are investigated in the general linear model situation. Properties of bias reduction and standard error estimation are derived. and the weighted jackknife shown to be superior for unbalanced data. There is a preliminary discussion of robust regression fitting using jackknife pseudo-values.     

设计价值思考

在进入21世纪之后,究竟什么样的设计理念和设计方式才是真正符合人类未来生活、符合自然规律需要的设计,其真正的价值何在?已成为当代设计必须认真思考和对待的重大问题。文章试图从由现代设计观念所引发的种种现象和问题入手,反思人类在“改造自然”、“创造文明”的同时,究竟创造了一个什么样的自然世界?由此对未来设计的价值观念作出新的思考。     

一种低压成套无功补偿装置工频过电压保护和缺相保护检测仪的研究

国标GB/T 15576-2020《低压成套无功功率补偿装置》要求生产企业对每台低压无功功率补偿装置进行工频过电压保护试验和缺相保护试验(无缺相保护的装置除外).[1]由于低压无功功率补偿装置的容量大,该试验会增加企业的生产能耗和成本.本文通过对上述两个试验本质的分析,提出了可以用容量较小的电容器取代低压无功功...     

Quasi-Balanced Circuits for Measuring the Parameters of Multielement Two-Terminal Networks in the Case of a Nonsinusoidal External Supply

The principles for constructing quasi-balanced circuits for measuring the parameters of multielement two-terminal networks when they are supplied with a nonsinusoidal voltage or current are considered. Block diagrams of quasi-balanced compensation-bridge circuits for measuring the parameters of three-element and four-element inductive two-terminal networks are presented.     

An Approach for Robust Design of Reactive Power Metal Mixtures Based on Non-deterministic Micro-scale Shock Simulation

In this paper, we propose a method for the robust design of materials involving processes that are computationally intensive and selectively random. The material system considered is a reactive particle metal mixture (RPMM) composed of aluminum and iron oxide (Al+Fe₂O₃). Shock simulations of discrete energetic particle mixtures are performed to predict the system’s mechanical and thermal behavior that will be used by a designer of the mixture to achieve robust micro-scale reaction initiation. The method used to predict the behavior of the material system is the robust concept exploration method with error margin index (RCEM-EMI). An error margin index is a mathematical construct indicating the location of mean system performance and the spread of this performance considering both variability in design variables and models of the system. Variability in responses of a model may be due to system variation that cannot be easily parameterized in terms of noise factors. Furthermore, lack of data, due to the cost of simulations and experiments, leads to uncertain parameters in empirical models. System response variability and parameter uncertainty in an empirical model are estimated in a computationally efficient manner to formulate the error margin indices, which are then leveraged to search for ranged sets of design specifications. Finally, the RCEM-EMI is illustrated for designing a RPMM.     

Colour Adaptation in Picture-Viewing Situations

The chromaticities that appeared neutral were determined for ob ervers adapted to viewing conditions typical for projected transparencies. Neutrality was determincd by a naming technique. Adaptation to the picture area was found to be incomplete, except for colour temperatures in the range 5500 to 6500 K. Neutral points were also determined for a typical television picture with various amounts of ambient tungsten light.     

Accuracy in Estimating the Repetition of Extreme Situations

Methods are considered for estimating the frequencies (repeatability) of extreme situations of natural and man-made type on the basis of existing statistical data. Formulas are derived for the estimator accuracy, and methods are proposed for improving them.     

反应等离子喷涂功率对Ti-C—N涂层性能的影响

Ti-C—Ni涂层的性能受反应等离子喷涂工艺参数的影响较大。采用反应等离子喷涂以不同的功率30．0,27．5,25．0kW在45钢表面制备了Ti—C—N涂层。对涂层进行了SEM,XRD,EDS,显微硬度分析和电化学行为分析。结果表明：不同功率制备的Ti—C—N涂层厚度约为150μm;随喷涂功率降低,涂层的硬度下降,喷涂功率为25．0kW时获得的涂层较为致密,在3．5％NaCl溶液中的阳极极化存在很宽电位范围的钝化区,电流密度维持在较低水平,耐腐蚀性最佳。     

Considerations on the elements of quantifying human reliability

This paper attempts to provide a contribution for the discussion of what the term ‘data’ means and how the qualitative perspective can be linked with the quantitative one. It will argue that the terms ‘quantitative data’ and ‘qualitative data’ are not distinct but a continuum that spans over the entire spectrum of the expertise that has to be involved in the HRA process. It elaborates the rational behind any human reliability quantification figure and suggests a scientific way forward to better data for human reliability assessment.     

中国传统玩具再设计思考

简述了中国传统玩具的悠久历史和当前面临的市场困境,强调现代人对玩具新鲜感、安全感和差异性的要求.并通过对泰迪熊、芭比娃娃和乐高积木的案例分析,指出中国传统玩具再设计时应该注意世界化、时尚化和科技化方向.     

一种新的低压无功功率补偿装置放电试验测试仪的研发

随着电气产品的发展,低压无功功率补偿装置标准对装置内电容器放电试验的检测要求越来越高,各检测机构必须配以更先进的检验设备才能为电器企业提供更好的检测服务。本文通过引入虚拟仪器技术,将传感器、电子元件、采集卡、计算机等结合起来设计一套便携式低压无功功率补偿装置放电试验测试仪,实现数据采集、波形分析、参数计算、报表自动生成等功能,满足标准中的试验要求,提高工作效率和检测精度。     

高活性纳米金属铝的研究进展

综述了高活性金属粉,特别是高活性纳米铝粉的研究进展。详述了纳米铝粉的粒径对其熔点、表面氧化层厚度、氧化起始温度以及纳米铝粉的点火燃烧特性的影响,分析了高活性纳米金属铝目前存在的问题,指出了今后高活性纳米金属铝的研究方向。