六硝基菧溶液的νs(NO2)激发及弛豫过程的相干反斯托克斯拉曼光谱

研究含能材料的振动激发和弛豫过程能深入理解含能材料的超快动态响应过程. 利用亚皮秒分辨的相干反斯托克斯拉曼(CARS)技术,实验直接观察基态的六硝基菧溶液中ν_s(NO₂)激发峰位于1385 cm^-1,弛豫时间为0.38和8.5 ps. 飞秒CARS实验观察到相应的拍频现象.     

拟线性抛物方程的弱解

该文给出了拟线性退化抛物方程pa_t{u}+pa_x{f(u)}=pa_xx{A(u(x,t))}∈R^2_+×(0,+∞) ,u(x,0)=u_0(x),x∈R 一种弱解的新定义, 利用Div Curl引理证明了解的存在性．     

喷涂过程中薄壁件变形控制方法

薄壁工件采用等离子喷涂方法制备高熔点金属涂层，通常包括喷砂、喷涂、机械矫正等工序。在喷砂处理过程中砂粒连续地高速冲击基体工件，造成表面剥蚀，破坏了基体正、反两面的应力平衡；等离子喷涂过程中基体正、反两面的温差较大，且涂层升温、降温速度较快，基体正、反两面的膨胀、冷却不一致；以及后续的机械矫正等工序都会增加涂层及工件中的残余应力。通过分析工装设计、喷涂工艺、时效处理对基体残余应力变化的影响，探讨了消除残余应力、减小基体变形的有效方法。     

阿贝尔逆变换数据处理算法在电弧诊断中的应用

提出了一种由等离子体辐射投影值重建发射系数的阿贝尔逆变换数据处理算法。采用计算简单、变换精度高的Bockasten插值方法实现阿贝尔逆变换积分方程的离散化。在阿贝尔逆变换前,运用傅里叶变换频域低通滤波去除实验数据中的噪声,通过多项式插值弥补数据采样率过低、提高空间分辨力,并对投影数据进行对称化处理以消除数据偏离对称对结果的影响。运用此算法对实验数据进行处理,得到电流200 A、弧长5 mm电弧温度在阴极下方0.5 mm处最高,超过22000 K,与文献中结果一致。该算法能够有效地克服噪声对变换结果的影响,运算速度快、计算精度高、稳定性好,处理大量数据时具有明显的优势。     

竞赛综合能力训练(四)

1.计算: (1)12(1/7)×29×7/4-1.75×12(3/7)=__; (2)1/3 1/8 1/15 1/35 1/48 1/63 __。 2.n是比100小的自然数,且 8 8 …… 8 n个8是平方数,那么n的最小值是__;n的最     

纳米ZnO光催化降解甲基橙研究

以ZnSO4.7H2O和Na2CO3为原料,采用沉淀法制备纳米ZnO粉体。以甲基橙为研究对象,高压汞灯(主波长365nm)为光源,研究了催化剂用量、甲基橙初始浓度、光强度、电解质(Cl-、SO42-、NO3-)及pH值等对甲基橙降解率的影响。     

镉（Ⅱ）－1－苯基－3－甲基－4－苯甲酰基－吡唑啉酮－5配合物吸附波的研究

在ｐＨ４．８的ＨＡｃ－ＮＨ＿（４）Ａｃ介质中，Ｃｄ（Ⅱ）与１－苯基－３－甲基－４－苯甲酰基－吡唑啉酮－５（ＰＭＢＰ）生成配合物，于－０．６７Ｖ（ｖｓ．ＳＣＥ）出现一尖锐、灵敏的极谱波。镉含量在０．００１～１．μｇ／ｍＬ范围内与峰高成线性关系。用多种电化学方法研究了极谱波的性质及电极反应机理，证明－０．６７Ｖ处的极谱波为配合物吸附波，峰电流由中心离子Ｃｄ（Ⅱ）还原产生。配合物组成为Ｃｄ（Ⅱ）：ＰＭＢＰ＝１：１。试验了３０多种离子对峰电流的影响，用ＳｒＳＯ＿４共沉淀分离Ｐｂ（Ⅱ），再经巯基棉分离其它干扰离子。用于矿样中镉的测定，结果满意。     

激光等离子体射流驱动亚毫米直径铝飞片及姿态诊断

强激光烧蚀低密度有机材料形成等离子体射流碰撞,可以对材料进行准等熵加载,比激光冲击加载应变率低,相同压强下可以获得更高的压缩度和更低的温升,在状态方程、飞片加速等方面有很强的应用前景.在星光Ⅲ置上首次开展了等离子体射流驱动小尺寸铝飞片及姿态诊断联合实验.通过调控有机材料厚度和真空间隙长度,获得了厚度20μm、直径约400μm的铝飞片,飞片加速时间长达200 ns.基于ps拍瓦激光的高能X光背光照相结果显示铝飞片在飞行约400μm距离后仍然保持了很好的飞行姿态和完整性.     

Influence of nitrogen and magnesium doping on the properties of ZnO films

Undoped ZnO and doped ZnO films were deposited on the MgO(111) substrates using oxygen plasma-assisted molecular beam expitaxy. The orientations of the grown ZnO thin film were investigated by in situ reflection high-energy electron diffraction and ex situ x-ray diffraction(XRD). The film roughness was measured by atomic force microscopy, which was correlated with the grain sizes determined by XRD. Synchrotron-based x-ray absorption spectroscopy was performed to study the doping effect on the electronic properties of the ZnO films, compared with density functional theory calculations.It is found that, nitrogen doping would hinder the growth of thin film, and generate the NOdefect, while magnesium doping promotes the quality of nitrogen-doped ZnO films, inhibiting(N_2)Oproduction and increasing nitrogen content.     

The theory and experiment of solute migration caused by excited state absorptions

Nonsymmetrical transition from reverse-saturable absorption (RSA) to saturable absorption (SA) caused by excited state absorption induced mass transport of the CuPcTs dissolved in dimethyl sulfoxide is observed in an open aperture Z-scan experiment with a 21-ps laser pulse. The nonsymmetrical transition from RSA to SA is ascribed neither to saturation of excited state absorption nor to thermal induced mass transport, the so-called Soret effect. In our consideration, strong nonlinear absorption causes the rapid accumulation of the non-uniform kinetic energy of the solute molecules. The non-uniform kinetic field in turn causes the migration of the solute molecules. Additionally, an energy-gradient-induced mass transport theory is presented to interpret the experimental results, and the theoretical calculations are also taken to fit our experimental results.