碳酸盐岩流体包裹体(NaCl-H2O)的合成及捕获机理分析

对碳酸盐岩原生、次生流体包裹体的形成机理进行了分析，并分别在压力为100MPa、温度为400—300℃和350℃条件下，利用高温高压釜合成了碳酸盐岩原生、次生流体包裹体（NaCl-H2O），模拟了包裹体的形成过程，并利用激光拉曼光谱及显微测温技术对合成包裹体的成分、均一温度、盐度等参数进行了定量分析。结果表明，合成的原生、次生包裹体气相与空气成分相符，其均一温度分别为372．8℃和321．02℃，盐度分别为23．22％和19．54％．与实验前设定的条件相符，从而验证了合成包裹体的准确性，并为进一步分析包裹体相态奠定了基础。     

碳酸盐岩流体包裹体(NaCl-H2O)的合成及捕获机理分析

对碳酸盐岩原生、次生流体包裹体的形成机理进行了分析,并分别在压力为100 Mpa、温度为400～300℃和350℃条件下,利用高温高压釜合成了碳酸盐岩原生、次生流体包裹体(NaCl-H2O),模拟了包裹体的形成过程,并利用激光拉曼光谱及显微测温技术对合成包裹体的成分、均一温度、盐度等参数进行了定量分析.结果表明,合成的原生、次生包裹体气相与空气成分相符,其均一温度分别为372.8℃和321.02℃,盐度分别为23.22%和19.54%.与实验前设定的条件相符,从而验证了合成包裹体的准确性,并为进一步分析包裹体相态奠定了基础.     

纳米小孔光学近场分布的研究

扫描近场光学显微镜突破了传统远场光学的衍射极限 ,能够获得超高光学分辨率。亚波长尺寸的小孔作为扫描近场光学显微镜中常用的金属膜光纤探针的简化模型。研究光透过小孔后的近场分布特性 ,对理解和分析探针在近场成像中的作用十分重要。采用时域有限差分 (FDTD)方法研究了无限大理想导体屏上纳米小孔的近场分布 ,计算结果表明 ,入射偏振光从小孔出射后发生了退极化 ,即出射光含有与入射光偏振方向垂直的电场分量。文中详细分析了小孔的近场分布特征与退极化之间的关系 ,研究了小孔的形状以及入射光偏振态对近场分布的影响     

Magnetic trapping of neutrons

Accurate measurement of the lifetime of the neutron (which is unstable to beta decay) is important for understanding the weak nuclear force and the creation of matter during the Big Bang. Previous measurements of the neutron lifetime have mainly been limited by certain systematic errors; however, these could in principle be avoided by performing measurements on neutrons stored in a magnetic trap. Neutral-particle and charged-particle traps are widely used for studying both composite and elementary particles, because they allow long interaction times and isolation of particles from perturbing environments. Here we report the magnetic trapping of neutrons. The trapping region is filled with superfluid 4He, which is used to load neutrons into the trap and as a scintillator to detect their decay. Neutrons in the trap have a lifetime of 750(+330)(-200) seconds, mainly limited by their beta decay rather than trap losses. Our experiment verifies theoretical predictions regarding the loading process and magnetic trapping of neutrons. Further refinement of this method should lead to improved precision in the neutron lifetime measurement.     

Electrostatic trapping of ammonia molecules

The ability to cool and slow atoms with light for subsequent trapping allows investigations of the properties and interactions of the trapped atoms in unprecedented detail. By contrast, the complex structure of molecules prohibits this type of manipulation, but magnetic trapping of calcium hydride molecules thermalized in ultra-cold buffer gas and optical trapping of caesium dimers generated from ultra-cold caesium atoms have been reported. However, these methods depend on the target molecules being paramagnetic or able to form through the association of atoms amenable to laser cooling, respectively, thus restricting the range of species that can be studied. Here we describe the slowing of an adiabatically cooled beam of deuterated ammonia molecules by time-varying inhomogeneous electric fields and subsequent loading into an electrostatic trap. We are able to trap state-selected ammonia molecules with a density of 10(6) cm(-3) in a volume of 0.25 cm3 at temperatures below 0.35 K. We observe pronounced density oscillations caused by the rapid switching of the electric fields during loading of the trap. Our findings illustrate that polar molecules can be efficiently cooled and trapped, thus providing an opportunity to study collisions and collective quantum effects in a wide range of ultra-cold molecular systems.     

Influence of nanometric CeO_2 coating on high temperature oxidation of Cr

Isothermal and cyclic oxidation behavior of chromium and its superficially applied nanometric CeO2 samples were studied at 900℃in air. Scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and high resolution electronic microscopy (HREM) were used to examine the morphology and micro-structure of oxide films. It was found that ceria addition greatly improved the anti-oxidation ability of Cr both in isothermal and cyclic oxidizing experiments. Acoustic emission (AE) technique was used in situ to monitor the cracking and spalling of oxide films, and AE signals were analyzed in time-domain and number-domain according to the related oxide fracture model. Laser Raman spectrometer was also used to study the stress status of oxide films formed on Cr with and without ceria. The main reason for the improvement in anti-oxidation of chromium was that ceria greatly reduced the growing speed and grain size of Cr2O3. This fine-grained Cr2O3 oxide film might have better high temperature plasticity and could relieve parts of compressive stress by means of creeping, and maintained the ridge character and relatively low internal stress level. Meanwhile, ceria application reduced the size and the number of interfacial defects, while remarkably enhanced the adhesive property of Cr2O3 oxide scale formed on Cr substrate.     

范畴中的拟-morphic对象

本文引入了范畴中的拟-morphic对象,给出了其在p-exact范畴Abelian范畴中的一些性质.主要证明设A是p-exact范畴中的拟-morphic对象,则A的任一子对象均同构于A的一个像当且仅当A的任一像均同构于A的任一子对象;设C和D是Abelian范畴,F:C→D是完全忠实正合函子,且A∈Ob C,则A是...     

矩形线性恒定场的级数通解及其应用

从分离变量法和S-L型方程的本征值问题出发,推导了矩形线性恒定场通解的级数表达式,证明其随着边界条件类型的不同而有所不同,补充了现有资料的不足,进一步提高了有关电磁场的计算效率和精度,具有广阔的应用前景。     

静电场中植物细胞畸变与分析

用压电陶瓷变压器高压电源产生的静电场对碗豆根尖分生组织的影响进行了细胞学研究,并在电子水平上阐明了电场下植物细胞畸变的机理,经过电场处理的种子,根尖分生组织出现多核细胞和不同类型、不同程度的染色体畸变,这些现象在物理微观领域表现为状态与能量的不连续性,即量子性,可用量子势场分析方法导出局域态波函数及本征能级来描述。     

转子在静电支承系统中的转速衰减特性

高真空静电支承式旋转系统中,偏心转子在磁场和静电力矩作用下,产生转速衰减,从而降低了系统精度。该文建立了静电力矩的数学模型,确定了支承系统频率特性与静电力矩大小之间的关系。在此基础上设计了含陷波滤波器、带宽相对较低的支承系统,以改善其局部频率特性,消除静电力矩引起的转速衰减。实验给出了常规和改进支承系统的转速测量结果,并进行了比较,从中分离出静电力矩的大小。结果表明,通过改变支承控制系统局部频率特性,可以消除静电降速力矩,最终提高了转子转速的长期稳定性。     

壁流式过滤体捕集微细颗粒过程的数值模拟

压降是评价过滤体性能的重要指标。针对壁流式过滤体捕集微细颗粒物的过程,建立了描述通道内流场和颗粒层分布的一维非稳态模型。通过数值计算,研究了颗粒层滑移对颗粒层分布和过滤压降的影响,同时研究了过滤体结构参数与来流参数对过滤压降的影响。研究结果表明:颗粒层分布直接影响过滤压降,随着颗粒层滑移效应的加强,颗粒层由平坦转向直线递增型分布,过滤压降则先增后降;增加过滤体长度有助于降低过滤压降;增加过滤体孔目数,增加了过滤体工作初始阶段的压降,但可降低高颗粒沉积量时的过滤压降;此外,随来流流量和颗粒浓度的增加,过滤压降增加。     

实物投影在物理演示实验中的应用

根据教学经验介绍了实物投影在中学物理实验中的应用。     

Abelian范畴中Gorenstein内射对象

给出了Abelian范畴A和复形范畴Ch(A)中X-Gorenstein内射对象及YX-Gorenstein内射对象的定义,其中XA,YX={Y∈Ch(A)|Y是正合复形且KerdnY∈X}。研究了这两类Gorenstein内射对象的同调性质及它们的区别和联系。证明了若X是包含所有内射对象的自正交的满子范畴,则X∈Ch(A)是YX-Gorenstein内射的当且仅当Xi都是X-Gorenstein内射的。在此基础上研究了两类范畴中X-Gorenstein内射维数和YX-Gorenstein内射维数以及它们之间的关系。在一定的条件下,YX-G I dim(X)=Sup{X-G I dim(Xi)|i∈Z}。     

移动对象数据库将来查询方法研究

首先提出一个移动对象的轨迹模型,能建模低维和高维运动轨迹,并在此基础上提出一个具体的移动对象将来查询方法,该方法能应用于多种索引结构。本文基于R树结构,给出了对于不同查询形式的具体实现过程。     

高压静电喷洒机的试验

运用高压静电喷雾技术和控制技术对原有的喷洒机具进行了改进，以适应有毒药剂的大面积高效喷洒问题．改进后的机具以皮卡车为载具，车厢上安装独立汽油发电机，在驾驶室内可控制喷雾的启停、喷头的俯仰及旋转运动．在试验室内对喷雾系统进行试验，得出了雾滴平均直径和雾滴沉积量的分布特性。两者在试验喷幅内均呈现一致的双峰分布．进行了整机现场试验，对比了荷电与非荷电、不同药液及不同药液喷量下的灭蝗效果．结果表明，荷电工况优于非荷电工况；随着药液喷量的提高。近距离喷洒区域内的杀灭效果较好；锐劲特药剂对荷电的适应性能明显优于菊马乳油药剂．     

基于多尺度方法的单晶硅纳米切削

通过在关键区域采用分子动力学(原子)描述、在远场弹性变形区域采用有限元(连续介质力学)描述建立了单晶硅纳米切削的多尺度模型。在边界区域,分子动力学和有限元互为彼此提供边界条件从而实现分子动力学区域和有限元区域的耦合。利用多尺度模型研究了单晶硅的纳米切削过程,结果表明纳米切削中工件以推挤的方式在刀具前方形成切屑。纳米切削中工件的原子键长分布、不同配位数的原子数变化和工件MD区域的原子构型的研究表明,纳米切削中发生了4配位的金刚石立方α-Si向6配位的β-Si结构的转变,即相变是纳米切削中硅的主要变形机制。该研究实现了单晶硅纳米切削的多尺度建模,为进一步探索纳米切削的微观机理提供了一种有效手段。