MCA—888型机芯的O-U型状态选择机构

MCA—888型机芯是一种随身携带的袖珍型机芯,不但具有自动返带的功能(见本刊1994年12期“MCA—888机芯返带机构及其传动原理”一文),而且还具有O-U型状态选择功能。 O型状态是指在自动返带机芯中,当一盒磁带装入机芯呈放音工作状态时,磁带能够从A面放音运带至终,经自动返带,又从B面放音运带至终,转为A面放音,这样无限循环的往复放音功能。这好似沿着一个圆周的轨迹在运动。

企业管理中设备运行状态监测系统的应用

企业的设备运行监测系统是一个多学科、技术密集型的专业管理系统。是一个可以给企业带来安全、经济。

真型断路器模拟缺陷下分合闸线圈电流波形试验研究

高压断路器随着运行年限增长或多次操作后可能出现机构部件缺陷,严重时会导致断路器拒动故障。传统检测手段只能在停电试验下开展机械特性检测,难以在运行状态下检测机构状态。为此基于真型断路器搭建了断路器模拟机构缺陷下分合闸线圈电流检测装置,首先利用该装置模拟线圈电阻超标、线圈电压下降、线圈铁芯行程变化缺陷,开展断路器线圈电流波形规律研究,为断路器机构状态带电检测奠定了基础,最后针对该装置提出了后续研究方向。

Problem of interoperability in semantic web service system

In order to fully realize semantic interoperability among distributed and heterogeneous applications on the web, a set of effective interoperability mechanisms is presented. This mechanism adopts service interactive interfaces （SII） and service aggregative interfaces （SAI） modeled with abstract state machine （ASM） to abstractly describe the behavior of the invoked web service instances, which makes business processing accurately specify tasks and effectively solves the problems of communication and collaboration between service providers and service requesters. The mechanism also uses appropriate mediators to solve the problems of information and coinmunication incompatibility during the course of service interaction, which is convenient for service interoperability, sharing and integration. The mechanism＇ s working principle and interoperability implementation are illustrated by a use case in detail.

Introduction to Unity of Physics and Biology, Inorganic Life Materials

The unity between physics and biology refers to that the inorganic systems： the Solar System, galaxies and artificial systems have the same structures and functions as the organisms. The development of science and technology is demonstrating the intense unification trends of physics and biology and a holistic science and technology era is about to start. The physics and biology unify on the basis of the four seasons＇ law, which is the most important rule of the universe. Life is defined as the four seasons＇ whole with the structure and process of four seasons. The organism is basically structured into a dual four-season body by state-varying, state-stabilizing and control organizations. Animals, the Solar System and the earth are all the dual four-season bodies. In the unity between physics and biology, the inorganic life materials and inorganic life body can be manufactured artificially.

Energy-Efficient Beamforming for Two-Tier Massive MIMO Downlink

Heterogeneous networks(HetNets)consisting of macro cells with very large antenna arrays and a secondary tier of small cells with a few antennas each can well tackle the contradiction of large coverage of the network and high data rate at the hot spots.However,it is not permissible to assign orthogonal pilot sequences for all the supported users due to the large number.Hence,we propose a pilot reduction scheme based on the heterogeneous system configurations and the unique topology of this HetNet.The reusing of pilot sequences causes the presence of the contaminated channel state information(CSI) and results in receivers' Quality of Service(QoS) outage.With the contaminated CSI,we provide an energy-efficient beamforming based on minimizing the total power consumption while keeping the QoS constraints satisfied and restricting the QoS outage probability below a given specification.By applying the approach of Bernstein approximation and semi-definite relaxation,we transform the original intractable chance constrained program to a convex problem conservatively.Numerical results show that the average power consumption of the proposed beamforming for our pilot reduction scheme is close to that of the perfect CSI case.Since our scheme will greatly compress the length of pilot sequence especially for those highly densified network with large number of small cells,it will be crucially helpful to put such two-tier massive multiple-input and multiple-output(MIMO) systems into practice.

A comprehensive method for joint wear prediction in planar mechanical systems with clearances considering complex contact conditions

A comprehensive method to predict wear in planar mechanical systems with clearance joints is presented and discussed in this paper.This method consists of a system dynamic analysis and a joint wear prediction.As the size and shape of the clearance are dictated by wear and evolve with the dynamic response of the system,the contact between the journal and bearing could be conformal or non-conformal,which makes the contact conditions in clearance joints quite complicated.Therefore a modified contact force model is employed to evaluate the joint reaction force in this study.As the nonlinear stiffness coefficient is related to the physical and geometrical properties of contact bodies and varies with the deformation,this contact force model is applicable to different contact conditions between the journal and bearing.Furthermore,based on the Archard’s wear model,the amount of wear can be quantified in the joint.And the geometry is updated to reflect the evolving contact boundary.Then,the wear process and the contact force model are integrated into the motion equations of the system to perform coupled iterative analyses between system dynamic response and joint wear prediction.In addition,a slider-crank mechanism is simulated as an example to demonstrate efficiency of the proposed method and to carry out a parametric study on mechanical systems considering joint wear.The influence of clearance size and driving power are discussed and compared respectively.The index of concordance is introduced to quantify contributions of contact pressure and sliding distance to wear rate under different types of journal motion.This study could help to predict joint wear in mechanical systems with clearances and optimize mechanisms in design.

Convergence Rate of the Asymmetric Deffuant-Weisbuch Dynamics

This paper considers the convergence rate of an asymmetric Deffuant-Weisbuch model.The model is composed by finite n interacting agents.In this model,agent i’s opinion is updated at each time,by first selecting one randomly from n agents,and then combining the selected agent j’s opinion if the distance between j’s opinion and i’s opinion is not larger than the confidence radiusε0.This yields the endogenously changing inter-agent topologies.Based on the previous result that all agents opinions will converge almost surely for any initial states,the authors prove that the expected potential function of the convergence rate is upper bounded by a negative exponential function of time t when opinions reach consensus finally and is upper bounded by a negative power function of time t when opinions converge to several different limits.

Structure condition under initial enlargement of filtration

We address the question of how the structure condition is affected when one possesses some additional information at the very beginning of the investment period.The structure condition represents essentially an alternative to non-arbitrage conditions for the Markowitz’s portfolio optimization framework,and is crucial for the existence of the optimal portfolio in quadratic utility settings.Herein,we provide practical assumption on the initial market model and the additional information to preserve the structure condition.The stochastic tools that drive this result are a generalization of the Lazaro-Yor representation by Lazaro and Yor(1978)and optional stochastic integral.

Damping behavior of Ti_(50.1)Ni_(49.9) alloy in reverse martensitic transformation region

Damping behavior of Ti50.1Ni49.9 shape memory alloy during reverse martensitic transformation has been investigated by dynamic mechanical analyzer in a dual-cantilever mode. With the increase of strain amplitude, internal friction （IF） of the alloy increases in martensite and austenite states while decreases in transformation region. Based on the regularity of IF attenuation in isothermal condition, IFTr and （IFpT＋ 1FI） are decomposed from the strain amplitude dependent IF in transformation region. For practical application of shape memory alloys as a damping material, it is significant to evaluate the damping capacity by eliminating the influence of IFTr and consider its time independent real IF （IFpT＋ IFI）.

Tightening up the structure, lighting up the pathway:application of molecular constraints and light to manipulate protein folding, self-assembly and function

Chemical cross-linking provides an effective avenue to reduce the conformational entropy of polypeptide chains and hence has become a popular method to induce or force structural formation in peptides and proteins.Recently,other types of molecular constraints,especially photoresponsive linkers and functional groups,have also found increased use in a wide variety of applications.Herein,we provide a concise review of using various forms of molecular strategies to constrain proteins,thereby stabilizing their native states,gaining insight into their folding mechanisms,and/or providing a handle to trigger a conformational process of interest with light.The applications discussed here cover a wide range of topics,ranging from delineating the details of the protein folding energy landscape to controlling protein assembly and function.