Day‐Ahead Global Solar Radiation Forecasting Using Binary Trees and Factor Analysis

A method is proposed for forecasting global solar radiation. The method is based on weather information using binary trees and factor analysis. The feature of this method is that it is possible to use a simple linear forecasting equation. The method has been tested on meteorological and global solar radiation data obtained at several observation sites, and the results show that it is a promising means of maintaining the balance between demand and supply of electric power in power systems of the near future with a large number of photovoltaic systems installed.     

Alleviation Technique for Thermal Concentration on Specific Switching Devices in Zero‐Speed Driving of PMSM

In this paper, a technique is proposed for alleviating the thermal concentration on specific switching devices by using a zero‐sequence voltage in a three‐level inverter that drives a permanent magnet synchronous motor (PMSM) in a zero‐speed and high‐torque condition. The use of the PMSM in home electronics and industrial products has become widespread, since it can realize miniaturization and a high efficiency drive. However, a large DC current flows when the PMSM is used in a zero‐speed and high‐torque condition, for example, in the hill‐start of electric vehicles, start or stop of elevators, or servo lock of servo pressing machines, and so on. In these cases, the current flows in the specific switching devices and heat generation is locally concentrated. This problem is unavoidable in a conventional two‐level inverter. A technique that can change the current path in a three‐level inverter and control the losses generated in the switching devices is proposed. We evaluated the effects of the proposed technique through a circuit simulation in which the electrical characteristics of a commercially available power device were applied. The proposed technique can reduce the highest loss of the switching devices in the three‐level inverter by about 40% as compared to that in a conventional inverter. Moreover, a method is proposed that suppresses the neutral point potential variation between the power supplies. This method can also reduce the maximum loss of the specific switching devices by about 30%.     

铁损测试仪的校准方法之研究(一)

对单片硅钢片的铁损测试是硅钢片的生产和使用厂家如电机/变压器等产品质量的一项重要评价项目，本文就单片硅钢片铁损测试仪及其校准方法，从理论和实际应用两方面探讨了如何在不利用标准铁板对铁损测试仪进行校准的可行性，为铁损仪生产和使用厂家的设备校准提出了可靠的方法。     

Quality Evaluation of Fish Meat by 31 Phosphorus-Nuclear Magnetic Resonance

³¹Phosphorus-Nuclear Magnetic Resonance (³¹P-NMR) was used to evaluate degree of freshness of loach muscle depending on metabolic changes of high energy phosphate compounds. The phosphocreatine ([PCr])/inorganic phosphate ([Pi]) ratio was found to be a sensitive index of early metabolic hypofunction. Ratios of [PCr]/β-phosphate of ATP ([β-ATP]), and [Pi]/[β-ATP] were demonstrated to be appropriate indexes to estimate such metabolic changes in fresh fish. The intramuscular levels of creatine phosphate, ATP and pH were maintained at higher levels in blood-drained loach than in untreated fish. The freshness of fish which were bled and washed at lower temperatures were better preserved.     

叠片定子铁芯的磁性测试及品质管理

本文就电机类叠片定子铁芯的磁性测试技术,提出了自动判断的检测方法,并结合一些磁性材料的测试方式,对定子铁芯生产中的各阶段品质管理提供参考依据.本文所提出的测试方法,是电机类定子铁芯现场测试的良好品质管理方法之一.     

ABSORPTION OF CARBON DIOXIDE INTO AQUEOUS DIETHANOLAMINE SOLUTIONS

The rates of absorption of pure carbon dioxide into aqueous diethanolamine solutions were measured at 25^°C in a liquid-jet column and a wetted-wall column. Experimental results were analyzed with the chemical absorption theory based on the penetration model. Physical solubility of carbon dioxide in aqueous diethanolamine solutions was determined from the absorption rates measured in a near pseudo first-order reaction regime and was found to show a salting-out effect. The measured absorption rates were in good agreement with the theoretical predictions for gas absorption with an irreversible third-order reaction.     

Equivalence condition of optimal control problems†

Two optimal control problems which have the same optimal feedback control laws and identical minimum costs are said to be equivalent. The conditions for the equivalence of two optimal control problems have been presented by other authors, but it seems that the equivalence conditions given by other authors are not complete. In this paper, a necessary and sufficient condition for the equivalence classes is derived.     

Bioleaching of Rare Metals from Manganese Nodules by Thiobacillus Ferrooxidans

Manganese nodules, which constitute a potential future resource of rare metals, are composed mainly of oxides of manganese and iron, with various metals such as copper, nickel, and cobalt. Although physical and chemical processes have been developed for extracting the rare metals from manganese nodules, another possible process is the leaching of metals by microbial means.

This paper describes leaching of raw manganese nodules by sulfurous acid and sulfuric acid which are biologically produced by oxidation of elemental sulfur by Thiobacillus ferrooxidans. The bioleaching behavior of each metal from nodules was measured at 30°C and pH 2 in a well-mixed batch reactor. The metal content of the nodules used in this work was 0.29% Cu, 0.49% Ni, 0.27% Co, 16% Fe and 17% Mn by weights. For both the microbial system and the control culture containing no T.ferrooxidans, copper and nickel exhibited close to 100% leaching in two weeks and less than 5% for iron and manganese. On the other hand, leaching of cobalt was markedly accelerated in the microbial system reaching 50% in two weeks compared with the sterile control. The bioleaching rate of cobalt was enhanced as the initial sulfur-liquid loading ratio became higher, but is was practically independent of the nodule size which was less than 330 mesh. Moreover, there was an optimal relation between the bioleaching rate and the initial cell concentration, and the addition of T.ferrooxidans cells in excess of the optimal concentration resulted in a decrease in the leaching rate of cobalt.     

Direct Generation of Internse Compression Waves in Molten Metals by Using a High Static Magnetic Field and Their Application

Compression waves propagating through molten metals are contributed to degassing accelerating reaction rate,removing exclusions from molten metals and refining solidifcation structures during metallurgical processing of materials,In the present study ,two electromagnetic methods are proposed to generate intense compression waves directly in liquid metals.One is the simultaneous imposition of a high frequency electrical current filed and a static magnetic field ;the other is that of a high frequency magnetic field and a static magnetic field ,A mathematical model based on compressible fluid dynamics and electromagnetic fileds theory has been developed to derive pressure distri-butions of the generated waves in a metal.It shows that the intensity of compression waves is proportional to that of the high frequency electromagnetic force,And the frequency is the same as that of the imposed electromagnetic force,On the basis of theoretical analyses ,pressure change in liquid gallium was examined by a pressure transducer under various conditions.The observed results approximately agreed with the predictions derived from the theoretical analyses and calculations.Moreover,the effect of the generated waves on improvement of solidification structures was also examined .It shows that the generated compression waves can refine solidification structures when they were applied to solidification process of Sn-Pb alloy ,This study indicates a new method to generate compression waves by imposing high frequency electromagnetic force locally on molten metals and this kind of compression waves can probably overcome the difficulties when waves are excited by mechanical vibration in high temperature environments.     

磁声波对金属凝固组织的影响

提出了运用强磁场和交流电流的共同作用直接在金属液中产生声波（磁声波）的新方法，并研究了所生成的磁声波在细化合金凝固组织晶粒的效果，该方法可以从根本上解决机械声波无法在高温生产领域应用的难题，理论解析表明，运用交变电磁力在液体金属内生成的磁声波的强度和所施加的静磁场的磁感应强度和交流电流的电流密度的乘积成正比；电磁力的频率越大，生成的磁声波越接近于由机械振动产生的声波，实验中测定的磁声波压力和理论解析结果基本一致，这种方法产生的磁声波具有促进金属凝固组织晶粒细化的作用。