粘弹性介质中扩展裂纹与J积分

本文提出了在线弹性及粘弹性介质中扩展裂纹与路径无关的J~*积分,并给出了严密的证明。文中证明了J~*积分与扩展裂纹尖端的张开位移(动态COD)之间有简单的关系,同时利用J~*积分求得了粘弹性介质中变速扩展裂纹尖端的奇异性。当裂纹以常速扩展时,J~*积分与能量释放率、动应力强度因子之间也有简单的关系。利用这些关系,我们给出了动态COD与动应力强度因子之间的关系式。     

粘胶纤维接枝含磷阻燃单体的研究

用含磷、硫的阻燃共聚单体O,O-二乙基-O-烯丙基硫代磷酸酯与粘胶纤维在四价铈离子作引发剂的条件下,通过自由基共聚的方式制备了含磷、硫的改性粘胶纤维。通过红外光谱(FTIR)、热重分析(TG)、差热分析(DTA)、差示扫描量热分析(DSC)、X射线分析以及扫描电子显微镜(SEM)分析对所制备的改性粘胶纤维进行了表征及性能研究。结果表明,阻燃共聚单体接枝到了粘胶纤维的表面;改性后的粘胶纤维的热分解温度较未改性的粘胶纤维提前,且热性能显著提高。     

纤维素-[Amim]Cl浓溶液的稳态流变规律

对纤维素-氯代1-烯丙基-3-甲基咪唑([Amim]Cl)浓溶液在不同温度下的稳态流变规律进行了研究。测试结果显示:纤维素-[Amim]Cl浓溶液属于假塑性流体。运用Cross和Carreau两种黏度模型对实验数据进行拟合,得到了表观黏度的主曲线,通过Arrhenius方程确定了移位活化能(ΔEa)为91.86~164.97 kJ/mol。与纤维素-氯代1-丁基-3-甲基咪唑([Bmim]Cl)溶液、纤维素-N-甲基吗啉-N-氧化物(NMMO)溶液、熔融聚合物(如聚丙烯、聚乙烯等)的活化能以及流变规律进行了对比。结果表明,纤维素-[Amim]Cl浓溶液的ΔEa较高,温度对体系黏度影响较大。     

载气流速对高场不对称波形离子迁移谱的影响

载气流速是影响高场不对称波形离子迁移谱(FAIMS)的重要参数.以自制的高场不对称波形离子迁移谱仪为实验平台,在射频电场幅值3 kV/cm,频率500 kHz,占空比0.36的条件下,研究了载气流速对苯离子迁移谱谱峰强度和半峰宽的影响.实验结果表明: 载气流速为3.7 L/min时,苯样品的谱峰强度最大,仪器的灵敏度最高.随着载气流速的增加,谱峰半峰宽变宽,仪器的分辨率下降.载气流速为3 .0～3.7 L/min时仪器综合性能最佳.此结果对于控制迁移谱仪载气流速有重要的参考意义.     

Ce1-xFexO2复合氧化物的结构及其催化碳烟低温燃烧性能

用水热法制备了不同摩尔比的系列Ce1-xFexO2复合氧化物碳烟燃烧催化剂. 采用X射线粉末衍射(XRD)、比表面积(BET)、拉曼光谱(Raman)、H2程序升温还原(H2-TPR)及程序升温氧化反应(TPO)等技术考察了Fe含量对催化剂结构和性能的影响, 重点探讨了催化剂表面性质和体相结构与催化活性和稳定性之间的关系. 结果表明, Fe3+较难进入CeO2晶格中, 部分Fe2O3分散在CeO2表面. 铈铁固溶体(氧空位)有利于氧的吸附活化, 而表面氧化铁对提高催化剂的抗老化能力起着重要作用. Ce0.8Fe0.2O2有最高的Fe3+掺杂量, 有良好分散性的表面Fe2O3, 显示出最好的催化活性和稳定性, 催化碳烟的起燃温度(Ti)和生成CO2的峰值温度(Tp)分别为262和314 ℃. Ce0.8Fe0.2O2高温老化后的Ti和Tp仍较低, 分别为292和392 ℃.     

非接触法自动测量薄膜厚度

根据白光等厚干涉原理,基于单片机改造的迈氏干涉仪用于自动测量透明薄膜厚度,采用非接触性测量法。当迈克尔逊干涉仪静镜形成的虚像与动镜相交所成的夹角很小时,在光屏上看到彩色干涉条纹,插入薄膜后,光程差改变,彩纹消失。步进电机带动微调手轮转动,当彩纹再次出现,即可得出透明薄膜厚度。     

制备均一性靶丸过程中的影响因素

在激光聚变实验中,高球形度、高厚度均一性的靶丸经常通过乳液微封装方法来制备。利用T.Norimatsu的模型研究在靶丸制备过程中,界面间表面张力、油相粘度、壳层尺寸、壳层厚度的影响。结果显示:较大的表面张力,较小的壳层尺寸,会使胶囊具有更好的均一性。当外部变形形式不同的时候,油相的粘度对于壳层均一性会有不同作用。     

The structure and the potential energy function of AlSO(C_S,X~2A″)

By using the B3P86/aug-cc-pvtz method,the accurate equilibrium geometry of the AlSO(CS,X2A″) molecule has been calculated and compared with available theoretical values.The obtained results show that the AlSO molecule has a most stable structure with bond lengths of R OAl = 0.1864 nm,R OS = 0.1623 nm,R AlS = 0.2450 nm,together with a dissociation energy of 13.88 eV.The possible electronic states and their reasonable dissociation limits for the ground state of the AlSO molecule were determined based on the principle of atomic and molecular reaction statics.The analytic potential energy function of the AlSO molecule was derived by the many-body expansion theory and the contour lines were constructed for the first time,which show the internal information of the AlSO molecule,including the equilibrium structure and stable point.The analysis demonstrates that the obtained potential energy function of AlSO is reasonable and successful and the present investigations provide important insights for further study on molecular reaction dynamics.     

Spectroscopic investigations on NO+(x1∑+,a3∑+,A1Ⅱ) ion using multi-reference configuration interaction method and correlation-consistent sextuple b

Three low-lying electronic states (x¹∑⁺,a³∑⁺,and A¹Ⅱ) of NO⁺ ion are studied using the complete active space self-consistent-field (CASSCF) method followed by highly accurate valence internally contracted multi-reference configuration interaction (MRCI) approach in combination of the correlation-consistent sextuple basis set augmented with diffuse functions, aug-cc-pV6Z. The potential energy curves (PECs) of the NO⁺(x¹∑⁺,a³∑⁺,A¹Ⅱ) are calculated. Based on the PECs, the spectroscopic parameters R_e, D_e, ω_e, ω_eχ_e, α _e, B_e, and D₀ are reproduced, which are in excellent agreement with the available measurements. By numerically solving the radial Schrödinger equation of nuclear motion using the Numerov method, the first 20 vibrational levels, inertial rotation and centrifugal distortion constants of NO⁺(x¹∑⁺,a³∑⁺,A¹Ⅱ) ion are derived when the rotational quantum number J is equal to zero (J = 0) for the first time, which accord well with the available measurements. Finally, the analytical potential energy functions of these states are fitted, which are used to accurately derive the first 20 classical turning points when J = 0. These results are compared in detail with those of previous investigations reported in the literature.     

天线平台在风荷载作用下的响应分析

研究了自然界中脉动风的风谱及其数值模拟方式,生成一段脉动风时程曲线。仿真研究天线平台在脉动风载荷和稳定风载荷下的响应,对比分析表明,天线平台在脉动风荷载下的响应要大于国标规定稳定风的响应。最后,提出考虑脉动风荷载时以1σ置信度所对应的结果作为仿真评判标准。