A quantum search algorithm based on partial adiabatic evolution

This paper presents and implements a specified partial adiabatic search algorithm on a quantum circuit. It studies the minimum energy gap between the first excited state and the ground state of the system Hamiltonian and it finds that,in the case of M = 1,the algorithm has the same performance as the local adiabatic algorithm. However,the algorithm evolves globally only within a small interval,which implies that it keeps the advantages of global adiabatic algorithms without losing the speedup of the local adiabatic search algorithm.     

Dynamic models of pest propagation and pest control

This paper proposes a pest propagation model to investigate the evolution behaviours of pest aggregates. A pest aggregate grows by self-monomer birth, and it may fragment into two smaller ones. The kinetic evolution behaviours of pest aggregates are investigated by the rate equation approach based on the mean-field theory. For a system with a self-birth rate kernel I(k)=Ik and a fragmentation rate kernel L(i,j)=L, we find that the total number M₀^A(t) and the total mass of the pest aggregates M₁^A(t) both increase exponentially with time if L ≠ 0. Furthermore, we introduce two catalysis-driven monomer death mechanisms for the former pest propagation model to study the evolution behaviours of pest aggregates under pesticide and natural enemy controlled pest propagation. In the pesticide controlled model with a catalyzed monomer death rate kernel J₁(k)=J₁k, it is found that only when I<J₁B₀ (B₀ is the concentration of catalyst aggregates) can the pests be killed off. Otherwise, the pest aggregates can survive. In the model of pest control with a natural enemy, a pest aggregate loses one of its individuals and the number of natural enemies increases by one. For this system, we find that no matter how many natural enemies there are at the beginning, pests will be eliminated by them eventually.     

Half-plane diffraction of Gaussian beams carrying two vortices of equal charges

This paper derives explicit expressions for the propagation of Gaussian beams carrying two vortices of equal charges m=±1 diffracted at a half-plane screen, which enables the study of the dynamic evolution of vortices in the diffraction field. It shows that there may be no vortices, a pair or several pairs of vortices of opposite charges m=+1, -1 in the diffraction field. Pair creation, annihilation and motion of vortices may appear upon propagation. The off-axis distance additionally affects the evolutionary behaviour. In the process the total topological charge is equal to zero, which is unequal to that of the vortex beam at the source plane. A comparison with the free-space propagation of two vortices of equal charges and a further extension are made.     

Constructing infinite sequence exact solutions of nonlinear evolution equations

To construct the infinite sequence new exact solutions of nonlinear evolution equations and study the first kind of elliptic function, new solutions and the corresponding Bäcklund transformation of the equation are presented. Based on this, the generalized pentavalent KdV equation and the breaking soliton equation are chosen as applicable examples and infinite sequence smooth soliton solutions, infinite sequence peak solitary wave solutions and infinite sequence compact soliton solutions are obtained with the help of symbolic computation system Mathematica. The method is of significance to search for infinite sequence new exact solutions to other nonlinear evolution equations.     

药物防治害虫的动力学行为

在农业生产中,农作物往往遭到虫灾的破坏,人们经常采用喷洒农药的方式来消灭害虫.在这里提出药物杀虫模型来研究害虫的动力学演化行为.在这个模型中害虫集团通过单体出生来增大,同时由于害虫的扩散行为,害虫集团会发生分解.害虫集团还会由于药物的作用而减小.在平均场理论的基础上通过解主方程的方法来研究害虫的动力学演化行为.结果发现:只有当初始药物量B0大于或者等于一定值Bc时,害虫才会以指数递减形式被完全消灭,否则害虫将会以指数递增形式增长,药物最终被消耗掉.     

Temperature Effect on Hydrogen Evolution Reaction at Au Electrode

The temperature dependence of hydrogen evolution reaction (HER) at a quasi-single crys-talline gold electrode in both 0.1 mol/L HClO₄ and 0.1 mol/L KOH solutions was investigated by cyclic voltammetry. HER current displays a clear increase with reaction overpotential (η) and temperature from 278～333 K. In 0.1 mol/L HClO₄ the Tafel slopes are found to increases slightly with temperature from 118 mV/dec to 146 mV/dec, while in 0.1 mol/L KOH it is ca. 153±15 mV/dec without clear temperature-dependent trend. The apparent activation energy (Ea) for HER at equilibrium potential is ca. 48 and 34 kJ/mol in 0.1 mol/L HClO₄ and 0.1 mol/L KOH, respectively. In acid solution, Ea decreases with increase in η, from Ea=37 kJ/mol (η=0.2 V) to 30 kJ/mol (η=0.35 V). In contrast, in 0.1 mol/L KOH, Ea does not show obvious change with η. The pre-exponential factor (A) in 0.1 mol/L HClO₄ is ca. 1 order higher than that in 0.1 mol/L KOH. Toward more negative potential, in 0.1 mol/L HClO₄ A changes little with potential, while in 0.1 mol/L KOH it displays a monotonic increase with η. The change trends of the potential-dependent kinetic parameters for HER at Au electrode in 0.1 mol/L HClO₄ and that in 0.1 mol/L KOH are discussed.     

生物材料用Mg-Y-Zn-Zr合金的微观结构及体外降解行为

通过向纯镁中添加微量的合金化元素（Y、Zn和Zr）,采用熔融浇铸法制备了名义成分为Mg1.5Y1.2Zn0.44Zr四元可降解镁合金生物材料,并对其进行了均匀化处理和挤压。 对这3种状态的镁合金进行了微观结构及在模拟体液(SBF)中体外降解行为的测试和分析,结果表明,合金主要由α-Mg基体和Mg12ZnY第二相组成;合金经过挤压后的组织得到了明显的细化;因此挤压后合金的降解性能得到明显改善;合金在模拟体液中生成的降解产物主要是含Ca和Mg的磷酸盐。     

梯形管内壁等离子体离子注入鞘层扩展MATLAB-PIC数值模拟

基于MATLAB利用Particle-in-cell模型,对梯形管内壁等离子体离子注入过程,进行了二维数值模拟.计算结果表明在中心电极附近出现了"阳极鞘层",该鞘层内部不存在离子,而且在鞘层边缘离子密度最高.在上下管壁上的离子注入剂量呈现"m"形分布.通过对注入过程中等离子体密度分布和不同时间段管壁不同位置离子注入剂量的跟踪,发现"阳极鞘层"扩展行为是导致"m"形分布的原因.由于梯形管形状的不对称性,"阳极鞘层"的边缘向梯形长底方向扩展较快.在注入初始时刻离子注入的能量很低,随着时间延长离子能量逐渐升高,这是由离子初始位置决定的.可见梯形管自身形状决定了鞘层形状和最终的离子注入能量和剂量分布.     

ZnO nanorod arrays with tunable size and field emission properties on an ITO substrate achieved by an electrodeposition method

In the present work,vertically aligned ZnO nanorod arrays with tunable size are successfully synthesized on nonseeded ITO glass substrates by a simple electrodeposition method.The effect of growth conditions on the phase,morphology,and orientation of the products are studied in detail by X-ray diffraction(XRD),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).It is observed that the as-prepared nanostructures exhibit a preferred orientation along c axis,and the size and density of the ZnO nanorod can be controlled by changing the concentration of ZnCl2.Field emission properties of the as-synthesized samples with different diameters are also studied,and the results show that the nanorod arrays with a smaller diameter and appropriate rod density exhibit better emission properties.The ZnO nanorod arrays show a potential application in field emitters.     

多孔氮化硅陶瓷的微观结构、力学性能和气体透气性的研究

本研究中,以石油焦为造孔剂、Y2O3-Al2O3为烧结助剂,通过注浆成型制备出多孔氮化硅陶瓷.研究石油焦的加入量对多孔氮化硅陶瓷微观结构、力学性能及气体透气性的影响.结果表明:多孔氮化硅陶瓷的微孔是由长棒状的β-Si3N4晶粒互相搭接而成,大孔是由石油焦燃烧而成.随着石油焦加入量的增加,气孔率及达西渗透系数(μ)增大,但试样的抗弯强度降低.在起始α-Si3N4粉末中添加10wt;～50wt;石油焦、5wt; Y2O3-3wt;Al2O3 1800℃下保温2h制备出气孔率为37.08;～59.40;、抗弯强度为52.00～154.27 MPa、μ值为(3.04 ～6.87)×10-13m2的多孔氮化硅陶瓷.