贝克曼离心机故障排除两例

简要介绍贝克曼离心机触摸键盘失控和控制参数显示混乱两例故障的故障现象、故障分析以及故障排除方法。     

Probabilistic Controlled Teleportation of a Triplet W State

A scheme for probabilistic controlled teleportation of a triplet W state from the sender Alice to the distant receiver Bob is proposed. In this scheme, an m-qubit GHZ state serves as the control parameter. The m control qubits are shared by m（s1, s2… sm） spatially-separated supervisors. With the aid of local operations and individual measurements, including Bell-state measurement, Von Neumann measurement, and mutual classical communication, etc., Bob can faithfully reconstruct the original state by performing relevant unitary transformations. However, even if one participant does not cooperate during the process, the receiver Bob cannot fully recover the original state. This protocol can be extended to probabilistic controlled teleportation of an arbitrary N-qubit state and some other N-qubit entangled states.     

压电激励圆形曲梁的静态响应及位移控制

研究压电激励圆形曲梁的静态位移响应及位移控制的参数特性。将压电夹层圆形曲梁等效为单层结构,基于一维小曲率曲梁理论,建立其控制方程。在集中弯矩和径向集中力以及电载荷作用下,分析了带压电激励器的圆形悬臂曲梁的静态响应。与有限元结果比较表明:本文的理论模型能够模拟压电激励的小曲率圆形曲梁的静态响应。压电夹层圆形曲梁在任意位置的径向集中力载荷作用下,控制其自由端径向位移响应为零,求得控制电压的解析表达,数值分析表明:随着集中力载荷的位置变化和梁长的变化,最优控制电压将出现峰值和反号。     

含水量对TiO_2纳米管形貌控制参数的影响

以不同含水量的乙二醇溶液为电解液,采用阳极氧化法制备TiO2纳米管阵列。通过记录反应过程中电导率、粘度及回路电流随时间的变化曲线,研究含水量对电解液粘度、电导率及电流等过程参数的影响,分析了纳米管形貌尺寸与TiO2溶蚀所耗电荷量的关系。粘度初始值和初始电导率均与含水量呈三次关系,相关系数分别为0.992 5和0.977 8。在反应过程中,溶液粘度值有缓慢增加的趋势。由于不同含水量的电解液粘度的不同,H+和OH-数量不同,F-迁移速率不同,电导率-时间曲线及电流-时间曲线具有不同的变化趋势,并对其进行了理论分析。当水体积分数为4%,5%,6%和10%时,纳米管的形貌较为有序并且TiO2纳米管阵列表面的碎片较少,纳米管直径变化范围为50nm至72nm,长度变化范围为0.85~1.90μm。F-腐蚀氧化膜时所消耗电量与TiO2氧化膜被腐蚀掉的体积呈一次函数关系,即腐蚀电量越大,腐蚀掉的体积越大,为制备一定形貌尺寸的纳米管提供了一定的控制方法。     

An Exact Evolution Equation of the Curvature Perturbation for Closed Universe

As is well known, the exact evolution equation of the curvature perturbation plays a very important role in investigation of the inflaorresponding exacttion power spectrum of the flat universe. However, the c extension for the non-flat universes has not yet been given clearly. Interest in the non-flat, specially closed, universes has been aroused recently. The need for this extension is pressing. We start with the most elementary physical consideration and obtain finally this exact evolution equation of the curvature perturbation for the non-flat universes, as well as the evolutionary controlling parameter and the exact expression of the variable mass in this equation. We approximately perform a primitive and immature analysis on the power spectrum of non-flat universes. This analysis shows that the exact evolution equation of the curvature perturbation for the non-flat universes is very complicated, and we need to carry out many numerical and analytic works for this new equation in the future to judge whether the universe is fiat or closed by comparison of theories with observations.     

Adaptive control of bifurcation and chaos in a time-delayed system

In this paper, the stabilization of a continuous time-delayed system is considered. To control the bifurcation and chaos in a time-delayed system, a parameter perturbation control and a hybrid control are proposed. Then, to ensure the asymptotic stability of the system in the presence of unexpected system parameter changes, the adaptive control idea is introduced, i.e., the perturbation control parameter and the hybrid control parameter are automatically tuned according to the adaptation laws, respectively. The adaptation algorithms are constructed based on the Lyapunov-Krasovskii stability theorem. The adaptive parameter perturbation control and the adaptive hybrid control methods improve the corresponding constant control methods. They have the advantages of increased stability, adaptability to the changes of the system parameters, control cost saving, and simplicity. Numerical simulations for a well-known chaotic time-delayed system are performed to demonstrate the feasibility and superiority of the proposed control methods. Besides, comparison of the two adaptive control methods are made in an experimental study.     

Parametric study of control mechanism of cortical bone remodeling under mechanical stimulus

The control mechanism of mechanical bone remodeling at cellular level was investigated by means of an extensive parametric study on a theoretical model described in this paper. From a perspective of control mechanism, it was found that there are several control mechanisms working simultaneously in bone remodeling which is a complex process. Typically, an extensive parametric study was carried out for investigating model parameter space related to cell differentiation and apoptosis which can describe the fundamental cell lineage behaviors. After analyzing all the combinations of 728 permutations in six model parameters, we have identified a small number of parameter combinations that can lead to physiologically realistic responses which are similar to theoretically idealized physiological responses. The results presented in the work enhanced our understanding on mechanical bone remodeling and the identified control mechanisms can help researchers to develop combined pharmacological-mechanical therapies to treat bone loss diseases such as osteoporosis.     

Dependences of spin polarization on the control parameters in the spin-polarized injection through the magnetic p-n junction

Effective spin-polarized injection from magnetic semiconductor (MS) to nonmagnetic semiconductor (NMS) has been highlighted in recent years. In this paper we study theoretically the dependence of nonequilibrium spin polarization (NESP) in NMS during spin-polarized injection through the magnetic p-n junction. Based on the theory in semiconductor physics, a model is established and the boundary conditions are determined in the case of no external spin-polarized injection and low bias. The control parameters that may influence the NESP in NMS are indicated by calculating the distribution of spin polarization. They are the doping concentrations, the equilibrium spin polarization in MS and the bias. The effective spin-polarized injection can be realized more easily by optimizing the above parameters.     

Hopf Bifurcation Control of a Hyperchaotic Circuit System

This paper is concerned with the Hopf bifurcation control of a new hyperchaotic circuit system. The stability of the hyperchaotie circuit system depends on a selected control parameter is studied, and the critical value of the system parameter at which Hopf bifurcation occurs is investigated. Theoretical analysis give the stability of the Hopf bifurcation. In particular, washout filter aided feedback controllers are designed for delaying the bifurcation point and ensuring the stability of the bifurcated limit cycles. An important feature of the control laws is that they do not result in any change in the set of equilibria. Computer simulation results are presented to confirm the analytical predictions.     

高速磁浮双向主动控制系统模型参数分析

 磁浮控制系统是磁浮列车的重要组成部分,是保证磁浮运行的安全性和平稳性的关键部分．本文以PID控制器为研究对象,为了研究磁浮列车中悬浮控制的动态性能与控制参数的变化规律,建立了基于状态反馈的PID 磁浮控制系统的数学模型,并通过多体动力学软件SIMPACK 联合可视化仿真工具MATLAB/SIMULINK 建立了耦合分析模型,进行了多参数的比较分析．系统讨论了单磁铁控制器在不同PID 控制参数下,磁浮间隙和磁浮电磁铁加速度等监测控制量的变化曲线,并针对双向受力状态的不同,分别研究了具体工况下高速磁浮的竖向和横向控制性能．研究表明：本文所使用的高速磁浮控制系统模型,具有较强的抗干扰性和鲁棒性,控制性能优秀,其参数分析方法可为未来实际工程的建设提供技术支撑．