Study on design of micro-stirrer for thrombus dissolution

The cerebral thrombus or blood clot might cause cerebral stroke and even decease if the clot could not be dissolved within several hours after it was formed. This paper presents the fundamental study on design of a micro stirrer for high effective dissolution. Based on the experimental results, the micro stirrer was analyzed by FEM with the fluid-structure interaction (FSI) analysis. The stirring effect was evaluated by the movement of the stirrer and the flow around the stirrer, and the performance index associated with the dissolution performance was presented. Using the performance index, several types of stirrers were evaluated. The obtained results demonstrated that the dissolution performance of the stirrer was influenced by the shape and the volume of the PZT actuator.     

Screening of Catalysts for Acrylonitrile Decomposition

The catalytic decomposition of acrylonitrile over various metal components (Mg, Ca, Mn, Fe, Co, Ni, Cu, Zn, Ga, Pd, Ag, and Pt) supported on several metal oxides (Al₂O₃, SiO₂, TiO₂, ZrO₂, and MgO) and ZSM-5 was studied. The most promising catalyst was Cu-ZSM-5, which exhibited 100% conversion and at least 80% N₂ selectivity above 350 °C.     

Microscopic Calculation of Dielectric Loss at Microwave Frequencies for Complex Perovskite Ba(Zn1/3Ta2/3)O3

The dielectric loss tangent at microwave frequencies for the complex perovskite Ba(Zn_1/3Ta_2/3)O₃ was calculated with respect to the degree of structural disorder on B sites. Starting out from the equations of ion motion, dielectric loss was expressed in terms of the pair-correlation functions corresponding to the ordering of Zn and Ta ions on B sites. The characteristic length included in the pair-correlation functions corresponds to the average size of the region containing disorder in ion arrangements on B sites; thus the relation between the structural disorder on the B site and the dielectric loss tangent at microwave frequencies was clarified theoretically. The numerical results show that the microwave loss tangent values change their power from – 3 to – 6 with increasing degree of order on the B site, which agrees well with the experimental observations. Results obtained here confirm the physical origin of the microwave loss of complex perovskite Ba(Zn_1/3Ta_2/3)O₃.     

计算机网络发展新动向：智能网络开发研究

本文综述计算机网络发展的新动向-智能网络开发研究。确切地说,本文是以中日两国学者自1983年以来进行国际合作,共同开发研究智能网络这一高技术课题为持支环境,并在中日双方经过多次交流与总结成果的基础上,论述智能网络的发展过程,基本概念,定义与分类,系统结构与体系结构的开发及其展望等问题。     

Purposive Behavior Acquisition for a Real Robot by Vision-Based Reinforcement Learning

This paper presents a method of vision-based reinforcement learning by which a robot learns to shoot a ball into a goal. We discuss several issues in applying the reinforcement learning method to a real robot with vision sensor by which the robot can obtain information about the changes in an environment. First, we construct a state space in terms of size, position, and orientation of a ball and a goal in an image, and an action space is designed in terms of the action commands to be sent to the left and right motors of a mobile robot. This causes a state-action deviation problem in constructing the state and action spaces that reflect the outputs from physical sensors and actuators, respectively. To deal with this issue, an action set is constructed in a way that one action consists of a series of the same action primitive which is successively executed until the current state changes. Next, to speed up the learning time, a mechanism of Learning from Easy Missions (or LEM) is implemented. LEM reduces the learning time from exponential to almost linear order in the size of the state space. The results of computer simulations and real robot experiments are given.     

Enzymatic method of increasing phosphatidylcholine content of lecithin

An enzymatic method was established to increase the phosphatidylcholine (PC) contents of soybean and egg lecithins. Other phospholipids of lecithin were phosphatidylethanolamine (PE), phosphatidylinositol (PI) and phosphatidic acid (PA). Seven preparations of phospholipase D (PLD), PLD-1 to PLD-6 ofStreptomyces origin and PLD-7 of cabbage origin, were tested for their ability to increase PC by transphosphatidylation in the presence of choline chloride (CC). The reactions were carried out at 30 C in a biphasic system that consisted of an aqueous phase containing PLD along with a buffer (optimum pH) having desired concentration of CC and Ca²⁺ and an ethyl acetate phase containing lecithin phospholipids. Intermitttent samples were extracted and analyzed by HPLC. Four of six PLD’s ofStreptomyces origin showed good transphosphatidylation (increase of PC contents of soybean lecithin from approximately 35% to 60–70% on a phospholipid basis) at 2.5 M CC, but the other two microbial PLD’s completely hydrolyzed the phospholipids to PA. Cabbage PLD-7 showed poor transphosphatidylation. PLD-3 gave the highest PC contents (70%) at 1.75 M CC. One hundred percent transphosphatidylation of pure PE to PC was achieved with PLD-3. PI was inert to the attack of most PLD preparations examined with the exception that PLD-3 hydrolyzed PI significantly. Purified PI could not be transphosphatidylized to PC; 100% PA was formed. Soybean lecithin containing about 80% PC and purified egg yolk lecithin with 75% PC could be converted to products having 95% PC and almost 100% PC, respectively, by PLD-3 at 1.75M CC. Studies on Enzymatic Conversion of Phospholipids (v)     

Effectiveness of both ZnCl2- and SnCl2-containing molten salt catalysts for hydrogenation of Big Ben coal in the absence of a solvent

Hydrogenation of Big Ben coal (Australian bituminous coal) with 9.8 MPa H₂ for 3h at 400 °C has been carried out using a batch autoclave system in the presence of a molten salt catalyst such as ZnCl₂, SnCl₂, ZnCl₂-KCl-NaCl (3:1:1 mol ratio) and SnCl₂-KCl (3:2). The hexane-soluble (HS) yield decreases in the order: SnCl₂-KCl, SnCl₂, ZnCl₂-KCl-NaCl, ZnCl₂. The use of SnCl₂-containing melt is characterized by higher yields of both HS and benzene-soluble (BS) fractions and the suppression of gas yield compared with the use of ZnCl₂. The average aromatic unit and the molecular weight of HS increase in the order: ZnCl₂, ZnCl₂-KCl-NaCl, SnCl₂, SnCl₂-KCl. Chromatographic separation of HS fractions indicates that the saturate content is lowest and polar-material content is highest with the SnCl₂-KCl melt: this fact coupled with the structural parameters suggests that HS material with SnCl₂-KCl melt has, on average, a reasonably-high-molecular-weight skeleton which has more alkyl chains and heteroatoms. Micrographs of resulting benzene-insoluble (Bl) materials clearly indicated that the Bl particles were larger when ZnCl₂ was used than when the other melts were used, the Bl particles in these cases being of similar size. Lewis acidity and the viscosity of the molten salt appear to be related, in part, to the size of the Bl particles.     

Preparation and properties of optical notch filters of cholesteric liquid crystals

We investigated the influence of preparative conditions of cholesteric-liquid-crystal (CLC) solid films on their cholesteric structures. They are made of poly[γ-butyl- (or )-glutamate] (PBuL(D)G and triethylene glycol dimethacrylate (TGDM), and have the ability to reflect the light in a specified wavelength region. When these films were combined with conventional colour filters, the colour reproduction region was enlarged by about 25% in the area of the CIE chromaticity diagram.