点配法的改进

针对点配法求解精度低的问题,提出了一种改进方法,改进的点配法有较高的精度,使用该方法可以计算天线电流的导数分布。改进的点配法能以较高的精度求解第一、第二、第三类Fredholm积分方程。修正中波天线模型,按照模型可以精确求解天线输入阻抗。     

直升机武器系统作战精度研究及仿真

通过对影响作战飞机的各种误差进行仿真计算,从理论上分析了各种误差因素对整个火控系统精度的影响,提出了控制误差应主要控制的参数,为整个飞机系统的设计和误差分配提供了理论依据。     

Mn5(PO3(OH))2(PO4)2(H2O)4的水热合成和光谱研究

在水热反应条件下合成出具有红磷锰矿结构的Mn5(PO3(OH) ) 2 (PO4 ) 2 (H2 O) 4单晶 ,在X ray单晶结构分析的基础上 ,对其固体紫外可见漫反射光谱、红外光谱、荧光光谱和热重光谱进行了研究。结果表明 ,构成该化合物的PO4 四面体及MnO6 八面体通过共顶点或共棱方式相连接 ,与P ,Mn配位的氧分为 3类 :即端基氧 (Od)、二桥氧 (Ob)和三桥氧 (Oc)。因而在 2 10和 2 5 0nm左右出现了Od→Mn和Ob ,c→Mn的荷移跃迁吸收谱带 ;在 10 0 0～ 110 0cm- 1 处 ,P—O的伸缩振动峰分裂为 3个 ;70 0～ 980cm- 1 处存在 3类Mn—O的伸缩振动。对标题化合物分别采用 2 18和 310nm的光激发 ,分别在 35 4和 4 13nm产生强而尖锐的荧光光谱发射峰 ,表现了很强的光学效应。热重分析表明该化合物在 2 70℃以下结构保持稳定 ,在 2 70～36 0℃范围内失去配位水。量化计算得单点能为 - 4 5 5 8 6 5 95 5 5 1a u ;前线轨道能量HOMO(Alpha) =- 0 2 80 80a u ,LOMO(Alpha) =0 0 15 2 7a u ,能隙为 0 2 96 0 7a u ;HOMO(Beta) =- 0 2 5 919a u ,LOMO(Beta)=0 0 0 10 8a u ,能隙为 0 2 6 0 72a u ;偶极矩为 4 2 0 82Debye。     

InSb的Li替位形成能的从头计算

采用基于平面波展开的第一原理赝势法计算了锑化铟在锂替位到铟位置时的各种情况下的形成能与电子结构,讨论了锂替位的体积变化,电荷分布、能带结构及电子态密度等性质.结果表明,对于闪锌矿结构的InSb,锂的各种替位形成能大致在每个锂原子-2.2eV左右.该结果表明,不可能在嵌入初期Li插入到间隙位置之前发生替位反应,与实验结果一致.     

大口径平面光学元件超精密加工技术的研究

为了解决激光核聚变装置中大口径平面光学元件的批量制造难题,将先进制造技术和传统抛光技术相结合,提出了一种新的工艺方法,即使用ELID(在线电解)磨削代替传统的铣磨和初抛工序,以提高生产效率。利用数控抛光将工件抛光至最终的面形精度,以提高生产效率和减少边缘效应。将连续抛光作为最终加工工序,使加工工件的表面粗糙度和波纹度达到工程要求。实验证明这一新的工艺方法是可行的。     

四象限探测器用作激光准直的特性分析

以四象限光电探测器用作激光准直为例,对其探测原理、光电转换特性、影响探测精度的因素进行了理论分析。用数值模拟、实验验证了分析结果,并对影响探测精度的因素进行了深入的探讨,从而为四象限探测器用作激光准直提供了有力的理论依据。     

Synthesis,Crystal Structure and Theoretical Calculation of [2-（2,6-Dioxacyclohexyl）-5-methoxylphenols]2

The title compound [2-（2,6-dioxacyclohexyl）-5-methoxylphenols]2 was synthesized by the reaction of 2-hydroxyl-3-methoxylbenzaldehyde and 1,3-propanediol in the presence of DMF-DMS adduct and characterized by IR spectrum, UV-Vis spectrum and X-ray crystallography. The title compound belongs to monoclinic, space group P21 with a = 9.8967（10）, b = 8.2240（9）, c = 13.3654（14） A^°, β= 90.016（2）°, C11H14O4, Mr = 210.22, V = 1087.8（2）A^°3, Z = 4, Dc = 1.284 Mg/m^3, F（000） = 448,μ = 0.098 mm^-1, the final R = 0.0300 and wR = 0.0761 for 2070 observed reflections with I 〉 2σ（I）. The molecules are connected via intermolecular O-H…O hydrogen bonds into a 2D network structure. Moreover, theoretical investigations of the title compound with HF/6-31G（d） method were performed, and its stability, frontier molecular orbital composition and Mulliken charge distribution were also discussed. The compound is a bis-molecule. The two molecules stay together and could not be separated. Two crystallographically independent molecules exist in an asymmetric unit. The bond lengths and bond angles of the two molecules are slightly different with each other.     

Typical aromatic noncovalent interactions in proteins: A theoretical study using phenylalanine

A systematic study of CH ··· π, OH ··· π, NH ··· π, and cation ··· π interactions has been done using complexes of phenylalanine in its cationic, anionic, neutral, and zwitterionic forms with CH₄, H₂O, NH₃, and NH at B3LYP, MP2, MPWB1K, and M06‐2X levels of theory. All noncovalent interactions are identified by the presence of bond critical points (bcps) of electron density (ρ( r )) and the values of ρ( r ) showed linear relationship to the binding energies (E_total). The estimated E_total from supermolecule, fragmentation, and ρ( r ) approaches suggest that cation ··· π interactions are in the range of 36 to 46 kcal/mol, whereas OH ··· π, and NH ··· π interactions have comparable strengths of 6 to 27 kcal/mol and CH ··· π interactions are the weakest (0.62–2.55 kcal/mol). Among different forms of phenylalanine, cationic form generally showed the highest noncovalent interactions at all levels of theory. Cooperativity of multiple interactions is analyzed on the basis of ρ( r ) at bcps which suggests that OH ··· π and NH ··· π interactions show positive, whereas CH ··· π and cation ··· π interactions exhibit negative cooperativity with respect to the side chain hydrogen bond interactions. In general, side chain interactions are strengthened as a result of aromatic interaction. Solvation has no significant effect on the overall geometry of the complex though slight weakening of noncovalent interactions by 1–2 kcal/mol is observed. An assessment of the four levels of theory studied herein suggests that both MPWB1K and M06‐2X give better performance for noncovalent interactions. The results also support the fact that B3LYP is inadequate for the study of weak interactions. © 2008 Wiley Periodicals, Inc. J Comput Chem 2009     

霍林河褐煤热解甲烷生成反应类型及动力学的热重-质谱实验与量子化学计算

应用开放体系的热重-质谱联用技术(TG/MS)对未成熟的霍林河褐煤(镜质组最大反射率ROmax为0.33%)进行了热解模拟, 获得了甲烷的在线析出速率曲线. 曲线拟合结果表明, 甲烷生成速率曲线可以分解为5个峰, 结合化学动力学分析, 发现低温阶段甲烷的峰为吸附甲烷析出峰, 其余四个峰为热解甲烷的生成峰, 代表四类不同的化学反应. 将煤的结构特征及量子化学的理论计算相结合, 认为甲烷的生成包括4类反应, 类型1为与氧等杂原子相连的脂碳断裂; 类型2包含了两种反应, 一种是短链脂肪烃类官能团β位断裂, 另一种是所形成的长链脂肪烃类物质二次裂解; 类型3是与芳核直接相连的甲基热解脱落; 类型4为存在于煤结构中脂肪类物质的芳香化.     

原位水热合成的二(2,4-二(对硝基苯)-1,3,5-环戊二烯铜配合物的实验和理论研究

以4-硝基对苯腈,氨水和铜盐反应于在原位水热条件下合成了二（2,4-二（对硝基苯）-1,3,5-环戊二烯铜配合物,通过单晶X射线衍射,元素分析,红外,核磁光谱和热重分析等手段对其进行了表征。结构分析表明,铜与四个源自原位合成的配体上的氮原子配位形成平面四边形构型。基于密度泛函的理论计算对配合物的热力学稳定性进行了阐释。