Experimentally Determining Bloch Parameters of Hamiltonian for Single-Qubit Systems

By considering the identification problem of unknown but fixed Hamiltonian H = S0σ0 ＋∑i=x,y,z Siσi where σi （i = x, y, z） are pauli matrices and σ0=I, we explore the feasibility and limitation of empirically determining the Hamiltonian parameters for quantum systems under experimental conditions imposed by projective measurements and initialization procedures. It may be unsurprising to physicists that one can not obtain the knowledge of So no matter what kind of projective measurements and initialization are permitted, but the observation draws our attention to the importance of the parameter identifiability under different experimental condition. It has also been revealed that one can obtain the knowledge of ｜Sz｜ and Sx^2＋Sy^2 at most when only the projective measurement {｜0/（0｜, ｜1/（1｜} is permitted to perform on and initialize the qubit. Further more, we demonstrated that it is feasible to distinguish ｜Sx｜, ｜Sy｜, and ｜Sz｜ even without any a priori information about Hamiltonian if at least two kinds of projective measurement or initialization procedures are permitted. It should be emphasized that both projective measurements and initialization procedures play an important role in quantum system identification.     

激光诱导击穿光谱在核分析实验教学中的应用

为了适应核物理与核分析实验教学的需要,本文将激光诱导激光光谱测量以创新实验的形式引入到核工程类专业实验中.通过将纳秒激光脉冲与不同靶材作用,测量样品中各类元素的LIBS谱线,结合理论分析提取激光等离子体的电子温度和等离子体密度.假设单一元素谱线获得的等离子体密度为混合样品等离子体密度,计算得到未知重元素Fe的原子谱线展宽参数.     

遥感技术用于固体力学实验研究的新成果

在岩石、混凝土和钢材加载直到破坏的过程中用红外和微波遥感技术进行了观测研究．发现这些材料在加载过程中其红外和微波辐射温度、红外辐射波谱及红外热像均随应力的变化而变化．材料破坏前这些变化表现出某些前兆性特征．研究表明遥感技术可作为固体力学研究的一种新手段，并可望在工程上得到应用     

结晶聚合物中间层理论与实验佐证

概述了Ｆｌｏｒｙ和Ｙｏｏｎ由晶格模型出发，从理论上证明了结晶聚合物中间层的存在以及近年来许多学者采用多种实验技术确认中间层存在的事实。     

O-羧甲基壳聚糖纳米微粒制备及对Ni~(2+)吸附研究

将壳聚糖与氯乙酸反应,通过控制反应条件制备了取代度为0.71的O-羧甲基壳聚糖,将改性后的O-羧甲基壳聚糖与多聚磷酸钠反应,制备了粒径分布在370-710nm的O-羧甲基壳聚糖纳米微粒,透射电镜观察表明该微粒呈球状,平均粒径为450nm.在此基础上研究了O-羧甲基壳聚糖纳米微粒对工业电镀镍废水Ni~(2+)吸附性能,考察了溶液pH、Ni~(2+)起始浓度、平衡吸附时间、粒径等因素的影响,结果表明:O-羧甲基壳聚糖微粒最佳吸附条件是Ni~(2+)溶液pH为8.0、Ni~(2+)溶液起始浓度为33.28mg/ml、平衡吸附时间为0.5h、粒径较小的O-羧甲基壳聚糖纳米微粒对Ni~(2+)的吸附量要大于粒径较大的吸附量.     

颗粒流的动力学模型和实验研究进展

首先叙述了颗粒流研究的背景和基本概念,接着概述了颗粒流动力学研究的三种基本数学力学模型:颗粒动理论(kinetic theory)模型、摩擦塑性模型和离散元模拟模型.介绍了它们的基本原理,并分析了各个模型的优缺点和适用范围.随之,对颗粒流的实验研究情况作了简要的介绍,列举了研究中几种常用的试验方法和观测手段,以及观测到的一些典型现象.最后,我们简述了颗粒流研究的主要困难,并提出了某些有待解决的研究课题.      

Experimental study of heat transfer characteristics in oscillating fluid flow in tube

In the present work, an experimental investigation of heat transfer enhancement parameters of the oscillating flow heat exchanger under different frequencies, tidal displacement, and heat fluxes is carried out. The effect of different parameters on experimental effective thermal conductivity and convective heat transfer coefficient in cooling region is studied using correlations given by different researchers. A correlation for experimental effective thermal conductivity in terms of S²√ω is derived based on experimental data. This correlation is useful for predicting the optimum value of S²√ω before onset of turbulence.     

CPU散热器换热特性的实验研究

本文对两种不同类型的CPU散热器,整体平直翅片与分段式的平直翅片,在不同加热功率、不同流速下的强迫风冷的传热性能进行了实验研究,得出换热系数主要和来流速度有关,而与加热功率关系不大的结论,并将二者的换热性能进行了对比。结果表明,翅片2的换热系数随流速的变化更强烈,在其他相同条件下,其换热系数甚至可以达到翅片1的两倍。     

A novel cationic emulsifier used for preparing slow-cracking and rapid-setting asphalt: Synthesis,surface activity,and emulsification ability

A novel cationic emulsifier including nonionic fatty alcohol polyoxyethylene ether was synthesized in two steps from epichlorohydrin, octadecyl dimethyl amine, and fatty alcohol polyoxyethylene ether, and the intermediate product could also be used as an emulsifier. Their structures were characterized by FTIR, and the surface activities were investigated by surface tension, electrical conductivity, and HLB. The obtained results indicated that the critical micelle concentration (CMC) of the final product was low, 0.442 mmol/L, and the surface tension at the CMC was 41.02 mN/m. The hydrophile-lipophile balance (HLB) value was 12, which meet the requirements of asphalt emulsifiers. A series of experiments of the emulsified asphalt prepared by the emulsifiers were performed. The results showed that the emulsified asphalt could be stably stored for more than 5 days when the emulsifier was 2 wt% and the pH value was between 3 and 4. The result of demulsification experiments showed that the emulsifier is a slow-cracking and rapid-setting asphalt emulsifier.     

On the use of edge cracked short bend beam specimen for PMMA fracture toughness testing under mixed-mode I/II

In this paper an inclined edge cracked short beam specimen subjected to symmetric three-point bend loading was designed and examined for conducting mixed-mode I/II fracture toughness experiments. The aspect ratio (i.e. length to width ratio) and the loading span distance are considered much lower than the other conventional cracked bend beam samples. Crack tip parameters such as stress intensity factors and T-stress were computed numerically for this specimen by several finite element analyses and it was demonstrated that the specimen is able to produce full combinations of mode I and II including pure mode II. The practical capability of the short bend beam specimen was studied experimentally by conducting a set of mixed-mode fracture tests on PolymethylMethacrylate (PMMA) as a well-known model brittle material. The critical stress intensity factors, the direction of fracture kinking and the path of fracture trajectory were investigated both experimentally and theoretically using two stress and strain-based fracture criteria. The fracture toughness of tested PMMA was decreased by moving towards mode II case due to the effect of T-stress on the fracture mechanism of the short bend beam specimen.