磁悬浮转子微陀螺的微细加工工艺研究

介绍了磁悬浮转子微陀螺的工作原理及有关的微细加工工艺。磁悬浮转子微陀螺的平面线圈是采用光刻、电镀及溅射等微细加工方法来实现的,微转子的加工有冲压、蒸铝沉积等方法,其中冲压能得到质量较好的微转子;上壳体采用体硅腐蚀来制作。初步的实验表明该方案是行之有效的。     

Design and Analysis of an Efficient Communication Strategy for Hierarchical and Highly Changing Ad-hoc Mobile Networks

In this work we introduce two practical and interesting models of ad-hoc mobile networks: (a) hierarchical ad-hoc networks, comprised of dense subnetworks of mobile users interconnected by a very fast yet limited backbone infrastructure, (b) highly changing ad-hoc networks, where the deployment area changes in a highly dynamic way and is unknown to the protocol. In such networks, we study the problem of basic communication, i.e., sending messages from a sender node to a receiver node. For highly changing networks, we investigate an efficient communication protocol exploiting the coordinated motion of a small part of an ad-hoc mobile network (the runners support) to achieve fast communication. This protocol instead of using a fixed sized support for the whole duration of the protocol, employs a support of some initial (small) size which adapts (given some time which can be made fast enough) to the actual levels of traffic and the (unknown and possibly rapidly changing) network area, by changing its size in order to converge to an optimal size, thus satisfying certain Quality of Service criteria. Using random walks theory, we show that such an adaptive approach is, for this class of ad-hoc mobile networks, significantly more efficient than a simple non-adaptive implementation of the basic runners support idea, introduced in [9,10]. For hierarchical ad-hoc networks, we establish communication by using a runners support in each lower level of the hierarchy (i.e., in each dense subnetwork), while the fast backbone provides interconnections at the upper level (i.e., between the various subnetworks). We analyze the time efficiency of this hierarchical approach. This analysis indicates that the hierarchical implementation of the support approach significantly outperforms a simple implementation of it in hierarchical ad-hoc networks. Finally, we discuss a possible combination of the two approaches above (the hierarchical and the adaptive ones) that can be useful in ad-hoc networks that are both hierarchical and highly changing. Indeed, in such cases the hierarchical nature of these networks further supports the possibility of adaptation.     

Probability distribution of an integral quadratic functional on the trajectories of a complex-valued Ornstein-Uhlenbeck process

The local limiting theorem for probability distribution density of random values of an additive quadratic functional over the trajectories of the complex-valued Ornstein-Uhlenbeck process is proved. The additive functional support is extended unlimitedly. A guaranteed estimate of the asymptotic formula derived is given.Translated from Kibernetika i Sistemnyi Analiz, No. 6, pp. 130–139, November–December 2004.This revised version was published online in April 2005 with a corrected cover date.     

A probabilistic scheme of independent random elements distributed over a finite lattice. II. The method of lattice moments

A new method is proposed for proving some theorems on the convergence of sequences of random quantities _n that assume values in a set {0,1,...,n} to discrete probability distributions. The method is based on the investigation of definite numerical characteristics (called lattice moments) of asymptotic behavior of distributions of _n and is illustrated by the examples of investigating the asymptotic behavior of the probability distribution of the solution space dimension of a system of independent random homogeneous linear equations over a finite field and that of the number of connected components of a random (unequiprobable) hypergraph with independent hyperedges.Translated from Kibernetika i Sistemnyi Analiz, No. 6, pp. 44– 65, November–December 2004.Part 1 was published in Cybernetics and Systems Analysis, No. 5, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Computer simulation of correlated self-diffusion via randomly migrating vacancies in cubic crystals

Title of program: RANDOM VACANCY MIGRATION Catalog number: ACKO Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland (see application form in this issue) Computer: CDC 6600; Installation: University of Stuttgart Operating system: Scope 3.4 Programming language used: FORTRAN IV High speed storage required: 58 000 words No. of bits in a word: 60 Overlay structure: none No. of magnetic tapes required: none Other peripherals used: card reader, line printer No of cards in combined program and test deck: 718 Card punching code: BCD     

计算机安全系统中随机序列发生器的研究

对当前计算机安全系统中几种常用的真随机序列发生器进行研究和分析,指出它们存在的主要问题是序列的输出数量不够多、质量较低、速度较慢．提出用Hash函数、傅立叶变换、小波分析、异和运算、增加随机源等方法用于真随机序列发生器中,目的是增加随机序列发生器的输出数量和消除偏差,以满足快速发展的计算机安全技术的要求．特别是小波分析理论在随机序列发生器中的应用以及增加微机电源作为随机源的设想是首次提出的．     

Packet Reservation Window Multiple Access for Microcellular Voice/Data Transmission

We propose a new packet reservation multiple access (PRMA) scheme for the joint transmission of voice and data traffics in a microcellular medium. The collision resolution protocol within the system is based on a modification of the window random access algorithm, which has superior properties compared to the conventional slotted Aloha. The proposed algorithm, which we call packet reservation window multiple access (PRWMA), works in distinct modes for voice and data without prioritization, and the user performs slightly different operations depending on the information type. Simulation results show that PRWMA outperforms PRMA by a significant margin in terms of voice user capacity.     

MgATP-induced conformational changes in a single myosin molecule observed by atomic force microscopy: periodicity of substructures in myosin rods

This paper discusses the conformational changes in a single myosin molecule directly observed using atomic force microscopy (AFM). The myosin molecules were pretreated in rigor solutions without MgATP or in relaxed solutions with various concentrations of MgATP. The images of these molecules were obtained using a tapping mode AFM. The results indicate that the orientation of the myosin's heads and tail strongly depend on the MgATP concentration. Without using MgATP, almost all of the myosin molecules are in the extended form; however, when MgATP is used, the molecules bend according to the level of MgATP concentration. The mean-square end-to-end distance of the myosin molecules is significantly shorter with p[MgATP] = 4 than with p[MgATP] = 6. The rod region did not show the same level of intensity along their length in the extended form. The rods exhibited clusters of discontinuity, which were identified as substructures. The size of these substructures change at intervals that are multiples of 14.3-14.5 nm, which reflects the periodicity of the alpha-helical coiled coils. The substructure clusters also correspond to the myosin crossbridge spacing in muscles (14.3 or 43 nm). These results suggest that the myosin's head bends in conjunction with the bending or tilting in the helical substructures. Conformational changes of the myosin molecule induced by MgATP seem to mimic the molecular motions in a muscle's force generation process.     

Differentiating random upper semicontinuous functions under the integral sign

In this paper we analyze sufficient conditions to guarantee the differentiability under the integral sign of a certain class of random upper semicontinuous functions depending on a real-valued parameter. Several concepts of differential for this mappings are considered: the Fréchet differentiability of the support function, the π-differentiability, the De Blasi differentiability, and thes-differentiability.