A BLOCK GENERALIZED MINIMUM BACKWARD (BGMBACK) ERROR ALGORITHM FOR NONSYMMETRIC LINEAR SYSTEMS

Many applications require the solution of large nonsymmetric linear systems with multiple right hand sides. Instead of applying an iterative method to each of these systems individually, it is often more efficient to use a block version of the method that generates iterates for all the systems simultaneously. In this paper, we propose a block version of generalized minimum backward (GMBACK) for solving large multiple nonsymmetric linear systems. The new method employs the block Arnoldi process to construct a basis for the Krylov subspace K m(A, R 0) and seeks X m∈X 0+K m(A, R 0) to minimize the norm of the perturbation to the data given in A.

Appropriate posture of cancer patients treated with PICC to prevent internal jugular vein ectopic

We aimed to study the appropriate posture of peripherally inserted central catheter （PICC） patients, to reduce the incidence of internal jugular vein heterotopia. Methods： From 2009 to 2013, a total of 290 cases with PICC were enrolled in our study. They were divided into two groups. The patients in control group took regular position, which mean pros- tration, upper limb of tube side was abduction 90°, head moved to puncture side in order to block the internal jugular vein. On the basis of conventional body position putting, posture of patients in observation group was improved, the head remain neutral, and had 180° angle with trunk longitudinal axis, not favor any side. After ensuring the upper limb abduction, had 90° angle with the trunk, then catheter was inserted slowly. The jugular venous catheter heterotopia rate was judged by X.ray results. Results： The jugular venous catheter heterotopia rate of control group and observation was 12.8% and 0.68%, respectively. The difference between two groups was statistically significant （P 〈 0.01）. Conclusion： The body posture improvement can prevent discomfort of patients and reduce the jugular venous catheter heterotopia rate of PICC.

基于成对曲线组合的柔顺机构设计

采用拓扑优化技术进行柔顺机构设计成功与否在很大程度上取决于所采用的机构几何表述方式.本文提出了一种全新的基于成对曲线组合(对线组)的表述方式.这种几何表述方式,首先确定机构的输入输出区域.虽然在初始阶段不知道机构在设计域的分布,但是载荷加载需要借助机构输入输出点,因此必须有至少一个加载区域,一个支撑区域和一个输出区域.将这些输入输出区域利用成对Bezier曲线直接或间接连接起来形成一种可以承载负荷的柔顺机构.这种几何表述方式生成的机构边界为曲线函数之组合,解决了拓扑优化设计中的锯齿和模糊边界问题,并且可以同时进行形状和拓扑优化并且保持结构边界的光滑,没有棋盘格现象和中间密度单元等.基于对线组进行柔顺机构表征,会产生一些复杂的结构,基于FG-FEM有限元法进行仿真分析求得响应.研究柔顺机构拓扑优化设计理论与方法,采用图的形式对机构对象进行编码,利用遗传算法的全局寻优能力寻找全局最优解,数据算例的结果表明,提出的方法正确有效.

Effects of temperature fluctuations on cuttlebone formation of cuttlefish Sepia esculenta

The morphological characteristics and the cuttlebone formation of Sepia esculenta exposed to different water temperature fluctuations were investigated under laboratory conditions. Temperature fluctuation cycles （15 cycles, 60 d in total） consisted of the following three regimes of 4 d duration： keeping water temperature in 26℃ for 3 d （Group A）, 2 d （Group B）, 0 d （Group C, control）; then keeping water temperature in 16℃ for the next 1, 2, 4 d. No significant difference in the survival rate was observed between the control and temperature fluctuation groups （P〉0.05）. Lamellar depositions in a temperature fluctuation cycle were 2.45±0.02 for Group A, 2.00±0.02 for Group B, and 1.78±0.02 for Group C （P〈0.05）. The relationship between age and number of lamellas in the cuttlebone of S. esculenta under each water temperature fluctuation could be described as the linear model and the number of lamellas in the cuttlebone did not correspond to actual age. Group A had the highest cuttlebone growth index （CGI）, the lowest locular index （LI）, and inter-streak distances comparing with those of control group. However, the number of lamellas and LI or CGI showed a quadratic relationship for each temperature fluctuation group. In addition, temperature fluctuations caused the breakage of cuttlebone dark rings, which was considered a thermal mark. The position of the breakage in the dark rings was random. This thermal mark can be used as supplementary information for marking and releasing techniques.

Solutions and Conditional Lie-Backlund Symmetries of Quasi-linear Diffusion-Reaction Equations

New classes of exact solutions of the quasi-linear diffusion-reaction equations are obtained by seeking for the high-order conditional Lie-Baeklund symmetries of the considered equations. The method used here extends the approaches of derivative-dependent functional separation of variables and the invariant subspace. Behavior to some solutions such as blow-up and quenching is also described.

Blow Up of Periodic Solutions to a Class of Quasilinear Hyperbolic Systems in Diagonal Form

In this paper, we discuss the blow-up of periodic solutions to a class of quasilinear hyperbolic systems in diagonal form, and make the accurate estimate of life-span. These results in this paper extend the conclusion [1-3].

Multi-solitons for a generalized Davey-Stewartson system

This paper studies multi-solitons of non-integrable generalized Davey-Stewartson system in the elliptic-elliptic case. By extending the method for constructing multi-solitons of non-integrable nonlinear SchrSdinger equations and systems developed by Martel et al. to the present non-integrable generalized Davey- Stewartson system and overcoming some new difficulties caused by the nonlocal operator B, we prove the existence of multi-solitons for this system. Furthermore, we also give a generalization of this result to a more general class of equations with nonlocal nonlinearities.

Elliptic systems involving multiple critical nonlinearities and symmetric multi-polar potentials

In this paper,a system of elliptic equations is investigated,which involves multiple critical Sobolev exponents and symmetric multi-polar potentials.By variational methods and analytic techniques,the relevant best constants are studied and the existence of(Zk×SO(N.2))2-invariant solutions to the system is established.

Convective Assembly of Linear Gold Nanoparticle Arrays at the Micron Scale for Surface Enhanced Raman Scattering

A convective assembly technique at the micron scale analogous to the writing action of a ＂pipette pen＂ has been developed for the linear assembly of gold nanoparticle strips with micron scale width and millimeter scale length for surface enhanced Raman scattering （SERS）. The arrays with interparticle gaps smaller than 3 nm are hexagonally stacked in the vicinity of the pipette tip. Variable numbers of stacked layers and clean surfaces of the assembled nanoparticles are obtained by optimizing the velocity of the pipette tip. The SERS properties of tile assembled nanoparticle arrays rely on their stacking number and surface cleanliness.

An exponential for the solutions model of collocation method of the HIV infection CD4＋T cells

In this paper, an exponential method is presented for the approximate solutions of the HIV infection model of CD4＋T. The method is based on exponential polynomi- als and collocation points. This model problem corresponds to a system of nonlinear ordinary differential equations. Matrix relations are constructed for the exponential functions. By aid of these matrix relations and the collocation points, the proposed technique transforms the model problem into a system of nonlinear algebraic equations. By solving the system of the algebraic equations, the unknown coefficients are com- puted and thus the approximate solutions are obtained. The applications of the method for the considered problem are given and the comparisons are made with the other methods.

Influence of temperature and LO phonon on the effective mass of bipolarons in polar semiconductor quantum dots

The temperature and LO phonon effects of the bipolaron in polar semiconductor quantum dots （QDs） are studied by using the Tokuda modified linear-combination operator method and the Lee-Low-Pines variational method. The expressions for the mean number ofLO phonons and the effective mass of the bipolaron are derived. Numerical results show that the mean number of LO phonons of the bipolaron decreases with increasing the temperature and the relative distance r between two electrons, but increases with increasing the electron-phonon coupling strength a The effective mass of the bipolaron M＊ increases rapidly with increasing the relative distance r between two electrons when r is smaller, and it reaches a maximum at r ≈ 4.05rp, while after that, 34＊ decreases slowly with increasing r. The effective mass of the bipolaron M＇ decreases with increasing the temperature. The electron-phonon coupling strength a markedly influences the changes of mean number of LO phonons and the effective mass M＊ with the relative distance r and the temperature parameter y.