三维圆锥沙堆崩坍的近黑体形式统计

由于颗粒位置矢量和接触矢量难以测量,体积系统理论无法实际应用。对此,本文类比黑体辐射过程对沙堆(λX =0.2)崩坍进行了数值研究,并分别对150目和200目铜粉堆进行了崩坍实验。结果表明：在150目铜粉堆中,崩坍规模m≤0.3g时拟合较好,而崩坍规模m≥0.5g时拟合较差;在200目铜粉堆中,崩坍规模m≤0.5g时拟合较好,而崩坍规模m≥0.8g时拟合较差。这说明体颗粒物质的动力学特性不具有遍历性。本研究还给出了一种求解有效体积的途径,从而为进一步深化颗粒物质体积系综理论研究提供了便利条件。     

数码相机综合评测系统

由于光电传感器、数字图像处理、电子元器件等各领域技术的发展,数码相机的成像质量在过去的十年里有了长足的发展。加工成本的下降使光电成像系统在众多领域得到广泛使用,成像镜头和成像系统的成像性能测试和评价也受到广泛的关注。数码相机可以方便地输出计算机识别的数字图像,而数字图像可以用计算机在无人干预的条件下自动处理,这使得数码相机成像质量的客观评测成为可能。在相关标准基础上,研究了数码相机多个参数的客观评测方法与计算方法。在单个参数评测的基础上,用基于属性模型评价的方法综合多个参数,对所评测的数码相机做出一个综合的等级评价和评分。     

Theoretical study of potential energy curves,spectroscopic constants,and radiative lifetimes of low-lying states in SeO molecule

The low-lying potential energy curves of SeO molecule are computed by means of ab initio multireference configuration interaction technique, taking into account relativistic (scalar plus spin-orbit coupling) effects. The spectroscopic constants of Ω states for X³Σ^-, a¹Δ, b¹Σ⁺, A³Π, A'³Δ, and A"³Σ⁺ states are obtained, and they are in good accordance with available experimental values. The Franck-Condon factors and transition dipole moments to the ground state are computed, and the natural radiative lifetimes of low-lying Ω states are theoretically obtained. Comparisons of the natural lifetimes of Ω states with previous experimental results and those of isovalent TeO molecule are made.     

NO选择性催化还原Ce-Mn-Ti-O催化剂铈组分助催化作用

用NH3程序升温脱附(NH3-TPD)、X射线衍射(XRD)、X射线光电子能谱(XPS)、H2程序升温还原(H2-TPR)和BET表面积测试结合NO选择性催化还原(SCR)微型反应评价等方法,研究了溶胶-凝胶法制备的Ce-Mn-Ti-O复合氧化物催化剂中铈组分的助催化作用.结果表明随铈含量增加,NO转化率大幅度增加,在Ce/Mn摩尔比约0.08时达极大值,其后随铈含量进一步增加,NO转化率又逐渐下降.适量铈组分的加入对Mn-Ti-O催化剂表面酸性影响不大,但增加了催化剂活性组分Mn物种的表面浓度,提高了Mn4+物种的相对含量和Mn物种的可还原性,从而提高催化剂低温SCR活性.当Ce/Mn摩尔比超过0.08,催化剂表面的Mn组分与Ce组分可能形成无定型结构的多层聚集的Ce-O-Mn物种,导致催化剂Mn/Ti摩尔比下降和Mn物种可还原性下降,从而导致催化剂SCR活性的下降.     

Theoretical study of potential energy curves,spectroscopic constants,and radiative lifetimes of low-lying states in an SeO molecule

<正>The low-lying potential energy curves of the SeO molecule are computed by means of an ab initio multireference configuration interaction technique,taking into account relativistic(scalar plus spin-orbit coupling) effects.The spectroscopic constants ofΩstates for X~3∑~-,a~1△,b~1∑~+,A~3Π,A′~3△,and A″~3∑~+ states are obtained,and they are in good accordance with available experimental values.The Franck-Condon factors and transition dipole moments to the ground state are computed,and the natural radiative lifetimes of low-lyingΩstates are theoretically obtained. Comparisons of the natural lifetimes ofΩstates with previous experimental results and those of isovalent TeO molecule are made.     

ICP—AES法测定生铁中硅锰磷的研究

通过正交试验选择出最佳溶样条件,用电感耦合等离子体发射光谱（ICP－AES）法测定生铁中硅,锰,磷,方法简便可靠,具有良好的精密度和准确性,相对标准偏差不大于3．8％。     

高能机械球磨法制备V-Ti-O超细微粒催化剂

负载型V2O5/TiO2氧化物催化剂因具有优良的催化性能而广泛地用于烃类选择性氧化[1,2]和氮氧化物选择性催化还原(SCR)[3]. 迄今,所研究的负载型V2O5/TiO2氧化物催化剂大多是采用浸渍法制备的[2,4～6],通过调整催化剂的组成[2,5]、引入适当的助剂组分[2,6]和选择适宜的反应操作条件[2,5]可进一步优化其催化性能.     

循环伏安方法制备掺杂二价金属离子的MnO2

循环伏安;掺杂;Cu2+;Co2+;MnO2;比电容     

微乳液体系相图的研究及其在纳米氟化物制备中的应用

绘制了十六烷基三甲基溴化铵(CTAB)/正丁醇(n-C₄H₉OH)/正辛烷(n-C₈H₁₈)/水[或NH₄F溶液、或Ba(NO₃)₂溶液、或KNO₃-Mg(NO₃)₂混合溶液]四组分微乳体系的拟三元相图.观察了电导率随水(或盐溶液)含量变化的规律,很好地印证了微乳液体系的相行为.选取相图中微乳区点作为最佳条件,制备了KMgF₃纳米粒子.     

Astrophysical Reaction Rates of the ^8Li（p, τ）^9Beg.s. Direct Capture Reaction

Based on the angular distribution of the ^8Li（d, n）^9Beg.s, reaction at Ec.m. = 8.0 MeV and distorted wave Born approximation analysis, the single particle spectroscopic factor S1,3/2 for the ground state of ^9Be = ^8Li×p is derived to be 0.64 ± 0.21. In addition, we deduce the astrophysical S-factors and rates of the ^8Li（p, γ）^9Beg.s. direct capture reaction at energies of astrophysical interests.