1Π态双原子分子中关于(A)量子干涉的微分干涉角

Sha等在静态池实验中观察到了转动能量转移中的碰撞量子干涉,并且计算了决定跃迁散射截面的积分干涉角(J.Chem.Phys.,1995,102:2772).由于积分干涉角是微分干涉角的平均效应,为了得到更精确的信息,进行了分子束实验.作者文运用含时微扰的一级波恩近似理论,提出了衡量干涉程度的1П态双原子分子中关于Λ量子干涉的微分干涉角.利用各向异性相互作用势计算了其干涉角.得到分子束实验中微分干涉角随实验参数,包括实验温度、碰撞伴、作用距离和转动量子数变化的关系.并且讨论了影响干涉角的各种参数.此理论模型对理解和进行分子束实验是非常重要的.     

1~Π态双原子分子中关于Λ量子干涉的微分干涉角(英文)

Sha等在静态池实验中观察到了转动能量转移中的碰撞量子干涉,并且计算了决定跃迁散射截面的积分干涉角(J.Chem.Phys.,1995,102:2772).由于积分干涉角是微分干涉角的平均效应,为了得到更精确的信息,进行了分子束实验.作者文运用含时微扰的一级波恩近似理论,提出了衡量干涉程度的1П态双原子分子中关于Λ量子干涉的微分干涉角.利用各向异性相互作用势计算了其干涉角.得到分子束实验中微分干涉角随实验参数,包括实验温度、碰撞伴、作用距离和转动量子数变化的关系.并且讨论了影响干涉角的各种参数.此理论模型对理解和进行分子束实验是非常重要的.     

1Π态双原子分子中关于量子干涉的微分干涉角

Sha等在静态池实验中观察到了转动能量转移中的碰撞量子干涉,并且计算了决定跃迁散射截面的积分干涉角(J.Chem.Phys.,1995,1022772).由于积分干涉角是微分干涉角的平均效应,为了得到更精确的信息,进行了分子束实验.作者文运用含时微扰的一级波恩近似理论,提出了衡量干涉程度的1П态双原子分子中关于Λ量子干涉的微分干涉角.利用各向异性相互作用势计算了其干涉角.得到分子束实验中微分干涉角随实验参数,包括实验温度、碰撞伴、作用距离和转动量子数变化的关系.并且讨论了影响干涉角的各种参数.此理论模型对理解和进行分子束实验是非常重要的.     

^1Π态双原子分子中关于∧量子干涉的微分干涉角

Sha等在静态池实验中观察到了转动能量转移中的碰撞量子干涉,并且计算了决定跃迁散射截面的积分干涉角（J.Chem.Phys.,1995,102：2772）.由于积分干涉角是微分干涉角的平均效应,为了得到更精确的信息,进行了分子束实验.作者文运用含时微扰的一级波恩近似理论,提出了衡量干涉程度的^1П态双原子分子中关于Λ量子干涉的微分干涉角.利用各向异性相互作用势计算了其干涉角.得到分子束实验中微分干涉角随实验参数,包括实验温度、碰撞伴、作用距离和转动量子数变化的关系.并且讨论了影响干涉角的各种参数.此理论模型对理解和进行分子束实验是非常重要的.     

真空紫外光激发下铕掺杂的硼酸盐发光特性与结构的关系

为了改进现有或开发新的PDP用荧光材料,必须考虑荧光材料的发光性质,如吸收峰位置、能量由基质到发光中心的传递效率、色纯度、发光强度等,而这些性质与荧光材料的结构有着紧密的联系.在研究了多种三价铕掺杂的硼酸盐荧光材料的基础上,比较了它们在真空紫外光激发下的吸收特性,定性讨论了能量从基质到发光中心的传递效率,分析了影响红色荧光材料色纯度的有关性质.     

转动传能中的量子干涉: 干涉角和相对速度的关系

考虑一级含时波恩近似和长程相互作用势, Sun提出了转动传能中的量子干涉模型.在静态池中CO A1Π～ e 3Σ-和He碰撞的实验已经成功模拟.为了从实验中直接获得碰撞速度和干涉角的关系, Sha提出了利用分子束和离子速度成像技术的实验.作为理论研究干涉角和碰撞速度的关系,计算了不同速度下的干涉角,同时获得了变化的趋势.对在分子束条件下(通过控制碰撞速度来控制干涉角)实验具有指导意义.     

基质辅助激光解吸电离飞行时间质谱对环状芳香多硫寡聚物的研究

采用基质辅助激光解吸电离飞行时间质谱(MALDI TOF-MS)对环状芳香硫醚的寡聚产物进行了测定和分析,首次确定了这类采用其它传统方法难以分析的难溶多硫环状芳香硫醚寡聚物的结构;研究了芳香烃部分随聚合度不同的分布规律和芳香烃部分相同的条件下S原子数目不同而引起的组分变化的规律;讨论了4种基质的辅助解吸电离效果和离子化试剂对测定结果的影响,探索出测定这类寡聚物的最佳条件.     

稀土配合物杂化发光材料的组装及光物理性质研究进展

稀土配合物兼具无机物稳定性好以及有机物荧光量子效率高的优点,而且具有可设计性,制备简便,容易修饰,荧光性质优异（发射谱带窄、色纯度高、荧光寿命长、量子产率高以及发射光谱范围覆盖可见和近红外光区等）．但配合物的光、热、化学稳定性和机械加工性能相对较差,因而限制了其在很多领域中的实际应用．近年来的研究表明,将稀土配合物引入到各种基质材料中可以改善其稳定性及机械加工性能,并对其光物理性质产生调制作用．根据基质材料的不同,杂化材料可分为无机基质、无机／有机复合基质及有机基质杂化材料．本文综述了这些不同基质稀土配合物杂化发光材料的研究进展,探讨了主客体间相互作用对杂化材料光物理性质及稳定性的影响,为实现稀土配合物杂化发光材料在光学器件领域（LED照明、光纤维、光学放大器及激光等）及生命分析领域的应用提供了重要的理论依据．     

镧系元素螯合物热致变色作用的研究(Ⅱ) 镧、钕、钆二甲酚橙螯合物水溶液的热致变色作用及机理

用分光光度法研究了镧系离子La(Ⅲ)、Nd(Ⅲ)和Gd(Ⅲ)的二甲酚橙(XO)螯合物水溶液的可逆热致变色规律。测定了螯合物的组成及条件稳定常数。探讨了体系酸度、离子强度及配体浓度对热致变色作用的影响。初步研究表明,Ln(Ⅲ)-XO螯合物水溶液中存在两种不同颜色的螯合物质子离解平衡:体系呈现的热致变色作用是平衡常数随温度而变化所致。     

汽车用聚氨酯减振材料的结构与性能

利用扫描电镜(SEM)对减振材料的微孔结构进行了表征;用万能材料试验机(UMTM)、动态热机械分析仪(DMA)、旋转流变仪表征了减振材料在不同条件下的力学及减振性能.研究发现:不同聚氨酯减振材料进入非线性形变区域的压缩形变大小与微孔的面积占有率相关.我们认为聚氨酯泡沫减振材料在小压缩应变下应力的缓慢增加主要是由微孔的变形引起的,随着压缩应变进一步增加,微孔的变形接近极限,此时应力的快速增加主要由聚氨酯本体的力学性能决定.聚氨酯减振材料的损耗能随着压缩应变的增加而增加,减振性能好的材料具有较大的损耗能.聚氨酯减振材料的损耗角随着压缩频率的增加而略有增加,其影响减振材料在不同使用频率下的减振和产热性能.聚氨酯减振材料的损耗角随着温度的变化而发生变化,耐寒性和耐热性好的材料,损耗角随温度平缓变化的温度范围更宽.当减振材料受到一定的负载后,材料的损耗角降低.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).