On delay-independent stability of large-scale systems with timedelays

A new criterion for delay-independent stability of linear large scale time-delay systems is deduced by employing an improved Razumikhin-type theorem and the m-matrix properties. An illustrative example is given to demonstrate the superiority of the obtained results to those in the literature     

Analogue implementation of a neural network controller for UPSinverter applications

An analogue neural-network controller for UPS inverter applications is presented. The proposed neural-network controller is trained off-line using patterns obtained from a simulated controller, which had an idealized load-current-reference. Simulation results show that the proposed neural-network controller can achieve low total harmonic distortion under nonlinear loading condition and good dynamic responses under transient loading condition. To verify the performance of the proposed NN controller, a hardware inverter with an analogue neural network (NN) controller (using mainly operational amplifiers and resistors) is built. Additionally, for comparison purposes, a PI controller with optimized parameters is built. Experimental results confirm the simulation results and show the superior performance of the NN controller especially under rectifier-type loading condition. Implementing the analogue neural-network controller using programmable integrated circuits is also discussed     

Synthesis and characterization of block copolymers from D,L-lactide and poly(tetramethylene ether glycol)

The copolymer from D ,L -lactide and poly(tetramethyene ether glycol) (PTMG) was prepared in bulk with an isotributyl aluminum–water–phosphoric acid complex catalyst as the initiator and characterized by H-NMR, GPC, and DSC. The effects of the temperature and the amount of PTMG on the polymerization rate and the molecular weight of copolymers were studied. The behavior of the degradation and delivery rate of Levonorgestrel microspheres in vitro was observed. The results show that the degradation and the delivery rate can be controlled by adjusting the molar rate of hydrophilic and hydrophobic segments of the copolymer © 1995 John Wiley & Sons, Inc.     

两种具有电双稳态的全有机络合物

首次发现两种在室温下即具有电双稳态的全有机（有机-有机）络合物，分别称为MCA＋TCNQ和BBDN＋TCNQ。它们可在真空中制备成薄膜，在数伏电压的作用下，从高电阻至低电阻的跃迁时间小于100ns，因此可作为一次写入的存储器材料。根据我国目前最小刻线宽度的水平，可望在1．6cm2的SiO2平面上做出64Mb的存储器。     

Investigation of the behavior of platinum-group elements during vitrification of model high-level wastes in application to an induction melter with a cold crucible

Conclusions In the process of vitrification of high-level wastes the platinum-group elements form at the calcination stage phases which have a limited solubility in the glass melts. If the dissolved part of the platinum-group elements, which at 1200–1300°C does not form more than 30% of their total concentration in the melt [3], is neglected, then apparently it can be assumed that the behavior of the dispersed particles of the platinum-group elements is determined by their thermodynamic stability, interaction with one another, and sedimentation, and the melts of the phosphate and borosilicate glasses play the role of an inert medium. Ruthenium dioxide and the solid solutions based on it, which contain up to 1.5% Ru, Rh, and Pd, are stable up to 1500°C. In the temperature range 1050–1200°C rhodium oxide and the solid solutions based on it, decompose and form metallic rhodium. Metallic palladium apparently forms at 800–900°C. In ceramic melters the temperature of the glass melt is equal to the temperature of the dispersed particles and the composition of the heterogeneous phase based on the platinum-group elements will be determined by the temperature chosen for performing the vitrification process. Induction heating results in local overheating of the electrically conducting dispersed particles by the high-frequency field and, irrespective of the process temperature, in the melt it forms alloys based on platinum-group elements. In summary, the local temperature of the dispersed particles will determine their phase composition, their density, and ultimately their rate of sedimentation and accumulation at the bottom of the melters. State Science Center of the Russian Federation A. A. Bochvar All-Union Scientific-Research Institute of Standardization in Machine Engineering. Translated from Atomnaya énergiya, Vol. 79, No. 1, pp. 34–37, July, 1995.     

Stochastic TCP friendliness: Expanding the design space of TCP-friendly traffic control protocols

While the current definition of TCP friendliness has enabled a wide variety of traffic control protocols other than TCP, it still considerably restricts the design space of TCP-friendly traffic control protocols. For example, some multimedia streaming applications prefer a smooth sending rate on a time scale of tens of seconds, however, a UDP flow maintaining such a long smoothness time scale is naturally not TCP friendly by the current definition. In this paper, we propose an innovative method to relatively compare the degrees of TCP friendliness of different traffic control protocols, and use it to define a new class of TCP friendliness definitions, called stochastic TCP friendliness (STF). STF greatly expands the design space of TCP-friendly traffic control protocols, while still effectively maintaining the desired fairness of the Internet. To demonstrate the expanded design space, we also develop a new congestion control protocol, called TCP-friendly CBR-Like Rate Control (TFCBR), for multimedia streaming applications which do not require a high sending rate but prefer a smooth sending rate on a time scale of tens of seconds. TFCBR is stochastically TCP friendly, however, it is not TCP friendly by the current definition.     

Pd/Mg(OH)2 Heterogeneous Nanocatalysts Synthesized by a Facile One-Pot Hydrothermal Method for CO Direct Esterification to Dimethyl Oxalate

Catalysis Letters - Pd-based heterogeneous nanocatalysts have wide application in chemical industry. However, the traditional synthesis process contains multi-steps such as impregnation, dry,...     

超滤在明胶生产中的应用

本文研究了超滤在明胶生产中的应用,超滤作为初级浓缩是可行的。同时,对超滤设备、超滤膜与工艺条件作了讨论。