空间低温技术的进展

综合介绍国外，主要是美国、西欧空间低温技术的最新进展。论述超流氦冷却技术及空间飞行中的液氦再供给等在轨机载验证、低温风洞技术、氢浆的制备和应用前景等。重点讨论目前在空间探测过程中最具竞争性的斯特林制冷机和脉管制冷机的最新发展。对可望在空间中应用的毫开（ｍＫ）级３Ｈｅ—４Ｈｅ稀释制冷机和绝热退磁制冷机及其它制冷技术也作简要介绍。最后对发展我国空间低温技术提出了建议。     

A reliable method for classification of bank notes using artificial neural networks

We present a method based on principal component analysis (PCA) for increasing the reliability of bank note recognition machines. The system is intended for classifying any kind of currency, but in this paper we examine only US dollars (six different bill types). The data was acquired through an advanced line sensor, and after preprocessing, the PCA algorithm was used to extract the main features of data and to reduce the data size. A linear vector quantization (LVQ) network was applied as the main classifier of the system. By defining a new method for validating the reliability, we evaluated the reliability of the system for 1200 test samples. The results show that the reliability is increased up to 95% when the number of PCA components as well as the number of LVQ codebook vectors are taken properly. In order to compare the results of classification, we also applied hidden Markov models (HMMs) as an alternative classifier. This work was presented, in part, at the 8th International Symposium on Artificial Life and Robotics, Oita, Japan, January 24#x2013;26, 2003     

Crystal structure of GeTe and Ge2Sb2Te5 meta-stable phase

Direct X-ray diffraction measurement of the erased state of the Ge–Sb–Te recording layer in a four-layered phase change optical disk, which was produced by an optical disk drive, was performed. It was identified as an fcc crystal structure. In order to carry out the detailed crystal structure analysis by the powder X-ray diffraction method with Rietveld refinements, somewhat larger amount of the fcc crystal powder was prepared from deposited 10 μm thick films. It revealed that Ge₂Sb₂Te₅ belongs to the NaCl type structure (Fmm) with the 4a site including 20% vacancies. The conclusion was supported by the results of the density measurements with Grazing Incidence of X-ray Reflectivity.     

Toxicity in rats fed diet containing iron lactate for 26 weeks

In order to characterize the toxicity of iron lactate, a 26-week feeding study was performed in male and female F344 rats. Animals were divided into 2 groups, and given diet containing iron lactate at concentration of 0 or 2%. No animals died during the administration period. Body weight gain was suppressed in both sexes of the 2% group compared with the 0% group. Hematologically, anemia was observed in male of the 2% group. Serum alkaline phosphatase decreased in both sexes of the 2% group. The spleen weight of both sexes and kidney weight of females were higher in the 2% group than in the 0% group. Lipid peroxide increased not only in the liver and the kidney homogenates of treated males and females, but also in the serum of treated females. Histopathologically, iron deposition was observed in the liver, the kidney and the spleen of treated males and females, and in the intestine of treated females. The present results indicate that the iron lactate administration caused iron deposition in the liver and the other several organs, resulting in lipid peroxidation in these organs.     

Finite element analyses of near-tip deformation in inhomogeneous elastic-plastic fracture specimens

Two types of path-independent expressions were derived for the nonlinear fracture parameter T^* integral in inhomogeneous multilayer materials. Finite element analyses were carried out for inhomogeneous elastic-plastic fracture specimens consisting of A533B steel and HT80 steel: these two materials have considerably different yield stresses, although their elastic properties are exactly the same. The T^*-integral for inhomogeneous materials demonstrated excellent path independence even in the stages of large deformations around the crack tip and material interfaces. Numerically generated moiré fringe patterns are in good agreement with experimentally recorded patterns. The shapes of plastic zones appearing in the specimens reveal large inhomogeneity effects. The applicability of a hybrid moiré-finite element method is demonstrated briefly.     

Wind velocity and rotor position sensorless maximum power point tracking control for wind generation system

In order to perform maximum power point tracking control of wind generation system, it is necessary to drive windmill at an optimal rotor speed. For that purpose, a rotor position and a wind velocity sensors become indispensable. However, from the aspect of reliability and increase in cost, rotor position sensor and wind velocity sensor are not usually preferred. Hence, wind velocity and position sensorless operating method for wind generation system using observer is proposed in this paper. Moreover, improving the efficiency of the permanent magnet synchronous generator is also performed by optimizing d-axis current using the Powell method.     

Balancing control method by dispersed generators based on H∞ control theory in DC power feeding system

Recently, dispersed generators have been installed in distribution network to supply power to commercial facilities. Renewable energy generation contains output power fluctuations and distributed generator produces sluggish response for power demand. In order to overcome these problems, an ultra capacitor energy storage system is used for compensating the instantaneous power imbalance. However, use of a large capacity ultra capacitor energy system increases system cost. In addition, PPSs (Power Producer and Supplier) that own these generators are supposed to achieve 30-min balancing control for stable supply of electric power. This paper proposes a control system to achieve both 30-min balancing control and interconnection point power flow control by using a fuel cell and an ultra capacitor based on the H_∞ control theory. Besides, remaining storage energy of the ultra capacitor is controlled to be constant to maintain compensation capability. Effectiveness of the proposed control system is verified by using simulation results.     

Strain mode of general flow: Characterization and implications for flow pattern structures

Understanding the mixing capability of mixing devices based on their geometric shape is an important issue both for predicting mixing processes and for designing new mixers. The flow patterns in mixers are directly connected with the modes of the local strain rate, which is generally a combination of elongational flow and planar shear flow. We develop a measure to characterize the modes of the strain rate for general flow occurring in mixers. The spatial distribution of the volumetric strain rate (or non‐planar strain rate) in connection with the flow pattern plays an essential role in understanding distributive mixing. With our measure, flows with different types of screw elements in a twin‐screw extruder are numerically analyzed. The difference in flow pattern structure between conveying screws and kneading disks is successfully characterized by the distribution of the volumetric strain rate. The results suggest that the distribution of the strain rate mode offers an essential and convenient way for characterization of the relation between flow pattern structure and the mixer geometry. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2563–2569, 2016     

Prediction of protein-protein interaction sites using support vector machines

The identification of protein-protein interaction sites is essential for the mutant design and prediction of protein-protein networks. The interaction sites of residue units were predicted using support vector machines (SVM) and the profiles of sequentially/spatially neighboring residues, plus additional information. When only sequence information was used, prediction performance was highest using the feature vectors, sequentially neighboring profiles and predicted interaction site ratios, which were calculated by SVM regression using amino acid compositions. When structural information was also used, prediction performance was highest using the feature vectors, spatially neighboring residue profiles, accessible surface areas, and the with/without protein interaction sites ratios predicted by SVM regression and amino acid compositions. In the latter case, the precision at recall = 50% was 54-56% for a homo-hetero mixed test set and >20% higher than for random prediction. Approximately 30% of the residues wrongly predicted as interaction sites were the closest sequentially/spatially neighboring on the interaction site residues. The predicted residues covered 86-87% of the actual interfaces (96-97% of interfaces with over 20 residues). This prediction performance appeared to be slightly higher than a previously reported study. Comparing the prediction accuracy of each molecule, it seems to be easier to predict interaction sites for stable complexes.