CCD电视经纬仪测角精度的室内检测及其误差源分析

用于多目标炸点坐标实时测量的CCD电视经纬仪是一种高精度的靶场测量设备,其测角精度等级优于1’,而高精度的测试设备又对检测方法和检测条件提出了更加严格的要求。本文简述了GK-312炸点坐标测量系统中CCD电视经纬仪测角精度的室内检测方法,分析了影响测量和检测精度的主要的误差因素。     

Hopf Bifurcation on a Two-Neuron System with Distributed Delays: A Frequency Domain Approach

In this paper, a more general two-neuron model with distributed delays and weak kernel is investigated. By applying the frequency domain approach and analyzing the associated characteristic equation, the existence of bifurcation parameter point is determined. Furthermore, we found that if the mean delay is used as a bifurcation parameter, Hopf bifurcation occurs for the weak kernel. This means that a family of periodic solutions bifurcates from the equilibrium when the bifurcation parameter exceeds a critical value. The direction and stability of the bifurcating periodic solutions are determine by the Nyquist criterion and the graphical Hopf bifurcation theorem. Some numerical simulations for justifying the theoretical analysis are also given.     

对比传统换药技术和负压封闭引流技术用于皮肤软组织损伤治疗安全性观察

目的对比传统换药技术和负压封闭引流技术治疗皮肤软组织损伤的疗效及其安全性。方法将吉安县万福中心卫生院2013年7月—2015年1月收治的皮肤软组织损伤患者98例作为研究对象,随机分为观察组和对照组,观察组采用负压封闭引流技术治疗,对照组采用传统换药技术进行治疗,比较两组疗效。结果观察组并发症仅1例,对照组出现肌肉萎缩4例,关节强直2例,3例创口感染,共9例并发症;观察组植皮时间较早,创面愈合情况与植皮愈合情况优于对照组,平均总住院时间少于对照组。两组数据对比差异显著(P0.05),有统计学意义。结论负压封闭引流技术治疗皮肤软组织损伤疗效优于传统换药技术,安全性较高,有临床推广价值。     

Combustion modeling and kinetic rate calculations for a stoichiometric cyclohexane flame. 1. Major reaction pathways

The Utah Surrogate Mechanism was extended in order to model a stoichiometric premixed cyclohexane flame (P = 30 Torr). Generic rates were assigned to reaction classes of hydrogen abstraction, beta scission, and isomerization, and the resulting mechanism was found to be adequate in describing the combustion chemistry of cyclohexane. Satisfactory results were obtained in comparison with the experimental data of oxygen, major products and important intermediates, which include major soot precursors of C2-C5 unsaturated species. Measured concentrations of immediate products of fuel decomposition were also successfully reproduced. For example, the maximum concentrations of benzene and 1,3-butadiene, two major fuel decomposition products via competing pathways, were predicted within 10% of the measured values. Ring-opening reactions compete with those of cascading dehydrogenation for the decomposition of the conjugate cyclohexyl radical. The major ring-opening pathways produce 1-buten-4-yl radical, molecular ethylene, and 1,3-butadiene. The butadiene species is formed via beta scission after a 1-4 internal hydrogen migration of 1-hexen-6-yl radical. Cascading dehydrogenation also makes an important contribution to the fuel decomposition and provides the exclusive formation pathway of benzene. Benzene formation routes via combination of C2-C4 hydrocarbon fragments were found to be insignificant under current flame conditions, inferred by the later concentration peak of fulvene, in comparison with benzene, because the analogous species series for benzene formation via dehydrogenation was found to be precursors with regard to parent species of fulvene.     

Theoretical study on the pyrolysis mechanism and kinetics of β-hydroxyketones

The mechanism and kinetics for the decomposition of β-hydroxypropaldehyde, primary and secondary β-hydroxyketones, were studied by using ab initio RHF/6–31G and RHF/6–31G^* methods. The activation barriers of these reactions were refined to be 39.57, 40.10, and 36.80 kcal mol⁻¹ at the MP2/ /RHF/6–31G^* level, respectively. The calculated results show that each decomposition is a concerted process with hydrogen transferring and bond breaking via a six-membered cyclic transition state. The thermal rate constants of the decomposition of primary and secondary β-hydroxyketones were obtained by calculating microcanonical probability fluxes through each transition state. It is theoretically confirmed that methyl substitution at the hydroxyl carbon of β-hydroxyketones causes a small enhancement in rates. The theoretical investigations of the mechanism and the rate constants are in agreement with the experimental results. © 1997 John Wiley & Sons, Inc.     

三元乙丙胶磺酸盐离聚物富氧膜的研究

对三元乙丙胶磺酸盐离聚物的合成、结构以及这种材料制成的膜对氧氨的透气性能和机械性能等进行了研究,结果表明,这种离聚物即使只有少量的磺酸基也仍然有离子聚集区或离子簇存在,少量磺酸盐基的引入不仅改良了三元胶膜的机械性能,而且提高了它对氧的透过系数和氧氮分离系数。     

酸性磷(膦)稀土萃取剂的空间结构和电子结构特征

用分子力学（Ｍｏｌｅｃｕｌａｒｄｙｎａｍｉｃｓ）、分子动力学及量子化学方法研究了系列酸性磷（膦）萃取剂的空间结构和电子结构。结果表明，它们存在较为明显的特征。空间结构方面，所有Ｐ原子均采取ｓｐ３杂化，萃取剂的空间结构取决于取代基之间的核排斥作用，在有两个２乙基己基的萃取剂中，其中一个取代基呈链状结构，而另一个呈弯曲结构。在电子结构方面，磷酰氧原子的负电荷随化合物中Ｏ原子数目的减少逐渐增多；羟基上Ｏ原子的负电荷和Ｈ原子的正电荷随着化合物中Ｏ原子数目的减少逐渐减小。各萃取剂电子占据前线轨道之间的能级相差较小，ＨＯＭＯ轨道和ＬＵＭＯ轨道的能级随体系中Ｏ原子数的减少而升高。这些结果为进一步研究萃取剂结构—性能关系和发展分子设计提供了有用的信息和数据。     

叠氮唑类高氮含能化合物的理论研究

基于2-叠氮-1,3-咪唑、3-叠氮-1,2,4-三唑和5-叠氮-1氢-四唑的晶体结构数据, 自行设计了同系列化合物叠氮-五唑的分子结构. 采用B3LYP方法, 选取6-311＋＋G**基组, 对叠氮唑类化合物进行优化并得到了稳定的分子构型, 结构参数与现有的实验数据相符. 故在此水平下对此系列化合物进行红外振动、键级及自然键轨道分析, 计算结果表明, 所有化合物均无虚频, 为势能面上的稳定结构, 分子中存在一个大的共轭体系|根据前线轨道能隙差(ΔE_L-H)得到4种化合物的热稳定顺序为: 5-叠氮-1-氢-四唑＞3-叠氮-1,2,4-三唑＞叠氮-五唑＞2-叠氮-1,3-咪唑|计算得到的生成热、密度、爆速爆压均随着体系中含氮量的增加而增加, 即叠氮-五唑的爆速、爆压最大, 爆速达到了9897 m•s^－1, 爆压达到了46.0 GPa, 在含能材料领域具有潜在的应用前景.     

A dual-level ab initio and hybrid density functional theory dynamics study on the unimolecular decomposition reaction C2H5O-->CH2O + CH3

We present a direct ab initio and hybrid density functional theory dynamics study of the thermal rate constants of the unimolecular decomposition reaction of C2H5O-->CH2O + CH3 at a high-pressure limit. MPW1K/6-31+G(d,p), MP2/6-31+G(d,p), and MP2(full)/6-31G(d) methods were employed to optimize the geometries of all stationary points and to calculate the minimum energy path (MEP). The energies of all the stationary points were refined at a series of multicoefficient and multilevel methods. Among all methods, the QCISD(T)/aug-cc-pVTZ energies are in good agreement with the available experimental data. The rate constants were evaluated based on the energetics from the QCISD(T)/aug-cc-pVTZ//MPW1K/6-31+G(d,p) level of theory using both microcanonical variational transition state theory (microVT) and RRKM theory with the Eckart tunneling correction in the temperature range of 300-2500 K. The calculated rate constants at the QCISD(T)/aug-cc-pVTZ/MPW1K/6-31+G(d,p) level of theory are in good consistent with experimental data. The fitted three-parameter Arrhenius expression from the microVT/Eckart rate constants in the temperature range 200-2500 K is k = 2.52 x 10(12)T(0.41)e(-8894.0/T) s(-1). The falloff curves of pressure-dependent rate constants are performed using master-equation method within the temperature range of 391-471 K. The calculated results are in good agreement with the available experimental data.     

基于双光子异构非线性的非相干耦合孤子族

理论研究了基于双光子异构非线性的非相干耦合孤子族的存在性.发现非相干耦合灰孤子族及暗孤子族可以在具有双光子异构非线性的块状聚合物中存在.若各分量成分具有相同的偏振和波长但彼此互不相干,可能形成这种孤子族.用数值方法详细地研究了这种非相干耦合灰孤子族及暗孤子族的存在条件及其特性.非相干耦合孤子族的每一个分量成分具有相同的半高全宽.当这一非相干耦合灰孤子族或暗孤子族在具有双光子光致异构非线性的聚合物中传播时,各分量成分光束都能稳定传播.研究表明,灰孤子族各分量成分具有横向运动速度,但暗孤子族不会在横向上发生移动.当这种非相干耦合孤子族只有两个分量成分时,它们自动退化成灰孤子对或暗孤子对.