Calculation of Photo-Ionisation Cross Sections and Radiative Recombination Rate Coefficients for CO and CO^+ Molecules

A method based upon the weighted total cross section （WTCS） theory is proposed to calculate the photo-ionisation cross sections and the radiative recombination rate coefficients between the fundamental level of CO and the main electronic states of its corresponding ion. Total photo-ionisation cross sections and radiative recombination rate coefficients are determined from the calculation of elementary vibrational photo-ionisation cross sections. Transitions be- tween CO＋（X, A and B） and CO（X） are considered. Total photo-ionisation cross sections and recombination coefficients are computed in the temperature interval 500-15000 K.

Ar^+/Ar, O_2^+/O_2 and N_2^+/N_2 Elastic Momentum Collision Cross Sections: Calculation and Validation Using the Semi-Classical Model

The aim of this paper is to obtain relevant sets of collision cross sections of the parent ions in low pressure discharges in argon, oxygen, and nitrogen, i.e., Ar＋ in Ar, O2＋ in O2 and N2＋ in N2. These ion data are first discussed and then validated from comparisons between the calculated transport coefficients and those measured in the literature. The elastic momentum transfer collision cross sections are determined from a semi-classical approximation for the phase shift calculation based on a 12-6-4 inter-particle potential while ion transport coefficients are determined versus the reduced electric field from Monte Carlo simulations.

State-to-state integral cross sections and rate constants for the N^(+)(3P)+HD→NH^(+)/ND^(+)+D/H reaction:Accurate quantum dynamics studies

The reactive collisions of nitrogen ion with hydrogen and its isotopic variations have great significance in the field of astrophysics.Herein,the state-to-state quantum time-dependent wave packet calculations of N^(+)(3P)+HD→NH^(+)/ND^(+)+D/H reaction are carried out based on the recently developed potential energy surface[Phys.Chem.Chem.Phys.2122203(2019)].The integral cross sections(ICSs)and rate coefficients of both channels are precisely determined at the state-to-state level.The results of total ICSs and rate coefficients present a dramatic preference on the ND+product over the NH^(+)product,conforming to the long-lived complex-forming mechanism.Product state-resolved ICSs indicate that both the product molecules are difficult to excite to higher vibrational states,and the ND^(+)product has a hotter rotational state distribution.Moreover,the integral cross sections and rate coefficients are precisely determined at the state-to-state level and insights are provided about the differences between the two channels.The present results would provide an important reference for the further experimental studies at the finer level for this interstellar chemical reaction.The datasets presented in this paper,including the ICSs and rate coefficients of the two products for the title reaction,are openly available at https://www.doi.org/10.57760/sciencedb.j00113.00034.

Gain properties of germanate glasses singly doped with Tm^(3+) and Ho^(3+) ions

Two kinds of germanate glasses singly doped with the ion concentration of 2.0mol.%Tm3＋ and 2.0mol.%Ho3＋, respectively, were prepared.According to McCumber theory, the absorption and stimulated emission cross-sections corresponding to the 3H6←→3F4 transitions of Tm3＋（at 1.8 μm） and the 5I8←→5I7 transitions of Ho3＋（at 2.0 μm） were obtained, and respective gain cross-section spectra were also computed as a function of population inversion according to absorption and emission cross-sections and the ion concentrations.For Tm3＋-doped germanate glasses, the maximum of the absorption, emission, and gain cross-sections reached a value higher than those reported for fluorozirconate, fluoride, and oxyfluoride glasses.For Ho3＋-doped germanate glasses, the maximum of absorption, emission, and gain cross-sections reached a value higher than that reported for fluorozircoaluminate glasses.Hence, these Tm3＋-doped and Ho3＋-doped germanate glasses exhibited an advantage for application in mid-infrared lasers at about 1.8 and 2.0 μm wavelength.

Electron Ionization Cross Sections of PF₃Molecule

Partial single and double differential cross sections with their sums through direct and dissociative ionization of PF3 have been evaluated at fixed electron energies 100 and 200 eV, by using modified Jain-Khare semi-empirical approach. To the best of my knowledge no other data of differential cross sections are available for the comparison. I have also calculated integral ionization cross sections with their ionization rate coefficients by using M-B distribution. No other data of partial ionization cross section are available till now. The sum/or total of evaluated partial cross sections reveal good agreement with available theoretical data.

Investigation on the Dielectric Properties of CO2 and CO2-Based Gases Based on the Boltzmann Equation Analysis

In this paper, the dielectric properties of CO2, CO2/air, CO2/O2, CO2/N2, CO2/CF4, CO2/CH4, CO2/He, C02/H2, CO2/NH3 and CO2/CO were investigated based on the Boltzmann equation analysis, in which the reduced critical electric field strength （E/N）cr of the gases was derived from the calculated electron energy distribution function （EEDF） by solv- ing the Boltzmann transport equation. In this work, it should be noted that the fundamental data were carefully selected by the published experimental results and calculations to ensure the validity of the calculation. The results indicate that if He, H2, N2 and CH4, in which there axe high ionization coefficients or a lack of attachment reactions, are added into CO2, the dielectric properties will decrease. On the other hand, air, O2, NH3 and CFa （ranked in terms of （E/N）cr value in increasing order） have the potential to improve the dielectric property of CO2 at room temperature.

Nuclear radiation shielding effectiveness and corrosion behavior of some steel alloys for nuclear reactor systems

Different types of nuclear parameters and corrosion behavior were deduced for carbon steel(AISI 1018),austenitic(304 SS),and duplex(2507 SS)stainless steel alloys.Three types of neutron energies as well as nine gamma ray energy lines(121.78-1407.92 keV)were used to evaluate the macroscopic neutron cross-sections(∑,cm^-1)and mass attenuation coefficients[σ,cm^2·g^-1)of gamma ray respectively.The corrosion behavior was investigated using different electrochemical techniques.The results showed that the stainless-steel alloys had a good attitude than that of carbon steel alloy for neutron and gamma ray parameters,especially the duplex stainless steel.The calculated values of mass attenuation coefficient using WinXcom computer program(Version 3.1),exhibited a very good agreement with the experimental values of that parameters.Moreover,the results indicated that duplex stainless-steel exhibited corrosion resistance higher than 304 SS and AISI 1018 steel alloys.

SHEAR STRESS ANALYSIS OF TIMOSHENKO'S BEAM WITH MULTIPLY CONNECTED CROSS SECTION

In this paper, a finite element method is developed to numericallyevaluate the shear coefficient of Timoshenko's beam with multiplyconnected cross section. With focus on analyzing shear stressesdistributed at the neutral axis of the beam, an improved definitionof the shear coeffi- cient is presented. Based on this definition, aGalerkin-type finite element formulation is proposed to analyze theshear stresses and shear deflections. Numerical solutions of theexamples for some typical cross-sections are compared with thetheoretical results. The shear coefficient of tower sections of theTsing Ma Bridge is calculated by use of the proposed approach, sothat the finite element modeling of The bridge can be developed withthe accurate values of the sectional properties.

Measurement of Mass Attenuation Coefficients of Indium With Characteristic X-rays From Targets Excited by Energetic Proton

The mass attenuation coefficients of indium are systematically measured byusing the characteristic X-rays from elemental or compound targets excited by energeticproton in the X-ray energy range 2.6 to 29.1 keV.The accuracy of experimental data isimproved to be±1%.The photoeletric cross sections are obtained by subtracting thescattering cross section from the measured total cross sections.Comparisons of our ex-perimental results with the available data of earlier investigations as well as with thetheoretical calculations are presented and discussed.

Photon Angular Distribution and Polarization of Radiative Recombination

A systematic study is carried out on the angular distribution and polarization of photons emitted following radiative-recombination of bare and He-like ions of Ne, At, Ni and Mo with a unidirectional electron beam. In order to incorporate the screening effect due to inner-shell electrons, a distorted wave method is used. Scaling rules for polarization of the photon following radiative recombination to both bare and He-like ions are given for the incident energy regions up to six times the ionization threshold energy of the final state.

A Study of Neutron and Gamma-Ray Interaction Properties with Cobalt-Free Highly Chromium Maraging Steel

Cobalt-free maraging steels of different compositions have been prepared by electro-slag remelting technique using titanium and chromium instead of cobalt. Neutron removal cross-sections have been calculated, also mass attenuation coefficients and effective electron densities have been determined for the prepared samples in the photon energy range up to 2.8 MeV. Other steel alloys and lead samples have also been investigated for the sake of comparison. The results prove the superiority of cobalt-free maraging steels compared with the other steel types to be used as a proper shielding material in the nuclear field. Among the investigated steels, the steel “0.045%C- 13.35%Ni-2.05%Cr-4.5%Mo-0.06%Ti” has the best attenuation properties.

变截面消声管道耦合Helmholtz腔结构的声学性能

基于局域共振理论与管道消声理论,设计了一种变截面消声管道耦合Helmholtz谐振腔的声学超材料结构,并运用COMSOL软件进行仿真研究.在此基础上,探讨了变截面声学超材料结构的几何参数对吸声系数峰值的影响,运用声学试验测试了该声学超材料结构的声学性能.结果表明:该变截面声学超材料结构在低频范围(200~600 Hz)内可实现良好的吸声效果;通过改变管道小孔的截面半径,可以实现声学超材料结构固有频率的定向调节;与普通Helmholtz腔相比,该声学超材料结构的吸声系数峰可在一定低频范围内移动,提高了结构在低频范围内的吸声效果,拓宽了吸声系数峰值对应频率的范围;声学超材料结构的几何参数得到了优化,具有良好的吸声效果.

表观扩散系数直方图对评估前列腺癌包膜外侵犯的附加价值

目的探讨磁共振表观扩散系数(ADC)直方图对评估前列腺癌包膜外侵犯(EPE)的附加价值。资料与方法回顾性连续纳入2021年1月—2022年12月于解放军总医院第一医学中心行根治性前列腺切除术,并于术前行标准多参数MRI扫描的100例前列腺癌患者,由2名放射科医师使用EPE分级系统独立评估图像,协商后确定评分。应用FireVoxel软件在ADC图上勾画全瘤体,进行直方图分析得到ADC平均值、第1、5、10、25、50、75、90、95和99百分位数ADC值(99th ADC)。比较组间差异,应用多因素Logistic回归筛选评估EPE的独立危险因素,并构建联合模型。采用受试者工作特征曲线评估效能,并比较曲线下面积。结果术后病理证实34例(34%)前列腺癌EPE阳性。ADC直方图分析显示EPE阳性与EPE阴性组间各参数差异有统计学意义(P<0.05)。多因素Logistic回归分析显示,99th ADC(OR=0.609,P=0.008)和EPE分级系统(OR=4.158,P<0.001)是评估EPE的独立危险因素。99th ADC、EPE分级系统及联合模型评估EPE的曲线下面积分别为0.756、0.805和0.856,99th ADC和EPE分级系统评估EPE的效能差异无统计学意义,联合模型的评估效能显著优于两者单独应用(Z=2.223、2.208,均P<0.05)。结论ADC直方图对术前评估EPE具有一定附加价值,99th ADC联合EPE分级系统能有效评估EPE。

低捻纱三维角联锁机织预制体的不稳定结构变形模型

为研究三维角联锁机织预制体在成形回转曲面过程中发生的形变,分析了预制体的结构不稳定因素及其变形类型,构建了预制体代表性体积单元的弯曲变形模型,探究了预制体几何结构参数与纱线截面变形系数之间的函数关系,得到了纱线在等量变形和非等量变形时织物花节长度、经纱倾角和纤维体积百分含量随纱线截面变形系数的变化规律。采用玻璃纤维制备三维角联锁机织预制体并进行弯曲试验,验证了该变形模型的合理性。认为:该研究成果可为低捻纱三维角联锁机织预制体二次成形回转曲面提供理论支持。

跨座式单轨独柱大悬挑钢-混组合框架高架车站抗震设计探讨

针对跨座式单轨独柱大悬挑钢-混组合框架高架车站结构抗震冗余度低,在高烈度地区应用较少,为更好地分析高架车站抗震受力全过程,以某跨座式单轨独柱大悬挑钢-混组合框架高架车站工程实例为背景,根据建筑规范和城市轨道交通规范要求设定合理的抗震性能目标,并研究构件抗震受力历时过程中的受力情况。采用大型有限元Midas作为主要计算软件,选取合理的地震波,进行多遇地震和设防地震有限元计算时采用弹性时程分析方法,且对振型分解反应谱法地震作用进行相应的放大,结果分析构件满足抗震性能目标要求。进行罕遇地震计算时,为更好地模拟工程实际情况,计算模型考虑桩土共同作用,采用结构-承台-桩基整体计算建模方法,进行弹塑性时程分析,关键构件采用截面纤维模型进行计算,能够反映关键构件在大震作用下进入破损阶段之后的行为,可以查看关键构件截面混凝土的开裂和压碎历史,钢材或钢筋的屈服和硬化过程。研究结果表明结构构件均满足抗震性能目标:(1)关键构件的钢材纤维受拉受压均未超过屈服强度,保持弹性工作状态,混凝土纤维受拉开裂,受压未达到屈服强度,同时延性系数D/D1小于1,均说明关键构件满足抗震性能为压弯、抗剪不屈服的目标;(2)桩基的钢筋纤维受拉、受压均未超过屈服强度,混凝土纤维受拉开裂,受压未达到屈服强度,满足抗震性能为压弯、抗剪不屈服的目标;(3)地震作用下,带有桩模型与无桩模型的基底剪力有一定差距,表现为带有桩基模型的地震剪力较大,设计时应考虑桩土共同作用。

截面削弱对轴心受压墙或柱稳定性的影响研究

为了解截面削弱与墙或柱危险点的关系,文章对不同位置受到不同程度截面削弱情况的轴心受压墙或柱的稳定性进行了研究。首先利用能量原理,推导在不同边界条件、轴心受压和小变形情况下,沿竖向受到不同位置、不同程度全截面削弱的墙或柱临界压力和稳定系数的近似计算公式,接着讨论了其相互关系,并提出了墙或柱稳定性加固的最优位置。通过与有限元软件计算结果的对比,探讨了近似公式的精度问题。在此基础上,运用等刚度代换法,提出了截面削弱在墙或柱不同水平位置所对应的稳定系数计算方法,并通过算例演示了其在工程中的应用。

对《砌体结构设计规范》中高厚比修正系数等问题的探讨

文章指出了《砌体结构设计规范》(GB 50003—2011)中关于带门窗洞口砌体墙允许高厚比的修正系数μ2的计算精度不足,并根据弹性稳定理论,提出了两端铰接变截面柱临界荷载Pcr的正确表达式,通过理论计算和有限元模拟对其给予了证明,此外,还推导了门窗洞口最不利布置时的μ2表达式。在此基础上,提出了比《砌体结构设计规范》(GB 50003—2011)更合理的有洞口墙体的允许高厚比修正系数μ2计算公式,同时对μ2的相关应用细则提出了修正建议。以修正后的两端铰接柱临界荷载Pcr为基础,提出了规范中变截面柱下段计算长度H0的更合理形式,为便于工程应用,最后对规范中有吊车房屋变截面柱计算长度的应用条款提出了修改建议。

采用有限单元法计算梁任意形状截面特性

采用将梁截面离散化的方式,用数值积分计算截面的几何特性,并根据梁剪切变形和扭转理论,利用变分原理建立截面的有限元法方程,求解任意形状截面的扭转常数、剪切中心以及剪切面积修正系数等特性。本方法适用于各种形式的截面,具有计算精度高及适应性强的特点。根据上述理论编制了相应程序,按照不同的单元划分方式,分别计算出矩形截面截面特性,与理论解进行比较;又对舟山市定海长峙至岙山预应力混凝土连续箱梁截面进行了计算,并与Ansys结果进行比较,均证明采用本文的计算方法能得到满意的结果,且该方法适用于各种形状的截面形式。

修、造船坞虹吸灌水流道的设计方法

船坞虹吸灌水与短廊道灌水和阀门灌水相比具有明显的优越性,但它对相关参数要求较高,给修、造船船坞虹吸灌水流道的设计增加了难度．为此,通过多个实际工程的水工模型试验,探索虹吸灌水流道的特性,探讨相关参数的关系与规律,总结出了船坞虹吸灌水的设计原理与方法,并建立了驼峰断面高度的计算公式．工程实例验证表明,该方法简便易行,减少了水工模型试验中大量的探索工作．

Ryff心理幸福感量表在河北师范大学生中的试用

目的:考察Ryff心理幸福感量表在河北师范大学生中的试用情况。方法:对河北师范大学958名大学生进行测试。结果:从内容上看该量表比较适合大学生这一群体的心理健康的测量。该研究表明,该量表的内部一致性比较好;Cronbach'sAlpha=0.93;该量表的分半信度系数及其各维度的信度系数低于测量学的要求;探索性因素分析表明,各个因子的项目分布与原量表的项目分布有一定的差距;验证性因素分析表明该量表构想效度不够理想。结论:要提高该量表在我国大学生中的使用的科学性需要进一步修订。