一种新型光致变色材料的合成与应用

由吲哚啉盐与水杨醛合成一种可光致变色的吲哚林衍生物,并测定其紫外光谱。此外,对其进行了光致变色现象测试。结果表明其在450nm处具有良好的光致变色性。     

硝化纤维素键合螺噁嗪光致变色材料的制备与研究

通过接枝共聚方式,将螺噁嗪类光致变色基团引入硝化纤维素,得到了一种均相光致变色功能高分子材料。利用核磁共振碳谱、红外光谱对其结构进行了表征。利用紫外-可见吸收光谱研究发现,产物在丙酮溶液中具有良好的光致变色性质,并且显色体消色热稳定性显著增强。新材料良好的脂溶性和光致变色性使其更具实用潜力。     

真空蒸发沉积18烷基取代螺吡喃薄膜的光致变色及光电子谱研究

利用真空蒸发的方法在玻璃载片上沉积了 18烷基取代螺吡喃薄膜 ,并利用光吸收谱和光电子谱研究了薄膜的光致变色特性及变色前后分子结构的变化情况。实验结果发现 ,真空蒸发沉积的 18烷基取代螺吡喃薄膜具有良好的光致变色性能 ,在紫外光的照射下可以发生明显的光致变色反映。光电子谱分析 :经紫外线照射后 ,N1s、O1s光电子峰发生明显的变化 ,说明经紫外线照射后分子结构发生了变化 ,导致分子内部电荷的重新分布。另外紫外线照射后氧含量增加 ,这是因为紫外线照射后薄膜表面对水汽的吸附能力增加所致     

真空蒸发沉积18烷基取代螺吡喃薄膜的光致变色及光电子谱研究

利用真空蒸发的方法在玻璃载片上沉积了18烷基取代螺吡喃薄膜，并利用光吸收谱和光电子谱研究薄膜的光致变色特性及变色前后分子结构的变化情况。实验结果发现，真空蒸发沉积的18烷基取代螺吡喃薄膜具有良好的光致变色性能，在紫外光的照射下可以发生明显的光致变色反映。光电子谱分析：经紫外线照射后，N1s、O1s光电子峰发生明显的变化 ，说明经紫外线照射后分子结构发生了变化，导致分子内部电荷的重新分布。另外紫外线照射后氧含量增加，这是因为紫外线照射后薄膜表面对水汽的吸附能力增加所致。     

有机光致变色化合物及其应用

综述了目前研究较多的几种有机光致变色化合物的光致变色反应、光变性能和研究进展,介绍了目前广受关注的双光子光致变色反应过程,以及有机光致变色化合物的应用,并展望了其发展方向.     

磷钼酸/有机硅涂层的光致变色性能研究

以磷钼酸为变色材料,氨基有机硅树脂为成膜物质成功制备了光致变色涂层,该光致变色涂层可用于自动划线新领域。并采用FT-IR、ESR和UV-Vis等测试手段对光致变色涂层进行了表征,研究了该光致变色涂料的光致变色性及其稳定性。测试结果表明,该变色涂料由黄色变为蓝色是因为其在紫外光的照射下,磷钼酸与氨基有机硅树脂中的氨基发生光氧化还原反应生成磷钼蓝所致,且该变色为不可逆变色。     

具有光致变色功能的纤维素接枝共聚物的制备与表征

以纤维素(Cell)为原料,通过原子转移自由基聚合(ATRP)在纤维素主链上接枝了4种乙烯基单体,然后通过酯化反应接枝螺吡喃衍生物(SP-OH),得到具有光致变色功能的纤维素接枝共聚物。采用核磁谱图、红外光谱、溶解性测试、紫外吸收光谱对所得样品的结构和性能进行表征。结果表明,所制备的具有光致变色功能的纤维素接枝共聚物可以在多种有机溶剂中溶解,并且具有良好的光致变色性能及循环使用的稳定性,在紫外光照射8 min后由白色变为深紫色,并且可以保持12 h不褪色。     

吲哚啉螺噁嗪光致变色化合物的研究进展

吲哚啉螺噁嗪以相对较高的化学稳定性、光敏性和抗疲劳性,可应用在光信息记录、光致开关、传感器、油墨印刷、防伪标识、光致变色纺织物和镜片等领域,从而希望成为实用性的光致变色材料之一,近年来引起了人们的浓厚兴趣。本研究从合成方法、光致变色机理、分散介质对其影响和新型吲哚啉螺噁嗪等方面入手,对其研究现状和动向进行综述,并展望了吲哚林螺噁嗪光致变色化合物的发展前景。     

具有离子识别能力的新型有机光致变色材料

有机光致变色材料是在特定波长的光照射下,生成同分异构体,同时在另一波长光照射或加热的条件下,该异构体可发生逆反应并伴随着明显的光物理化学性能变化的有机材料。将超分子化学的分子识别和光致变色相结合,可以实现客体操控材料的光致变色性能。基于其特殊的光切换性质,人们已开发出多种多响应、多功能材料并将其广泛应用于分子开关、分子逻辑门、分子机器、化学传感、生物成像等诸多领域。其中,具有离子识别能力的光致变色化合物因其易操作和廉价而成为最理想的该类材料之一。该类化合物不仅光致变色性质可以被离子所调节,同时也可以作为特异检测离子的新型光控探针。着重介绍近几年具有离子识别能力的光致变色材料的研究进展。最后结合现阶段的研究情况,对其前景和应用进行了展望。     

自乳化法制备光致变色微球

以甲基丙烯酸甲酯、丙烯酸正丁酯、丙烯酸等为单体,二丙烯酸-1,6-己二醇酯为交联剂,采用自乳化法制备了丙烯酸酯乳液。乳液的平均粒径为249nm,具有较好的单分散性。用该乳液对自制的光致变色材料螺吡喃进行包裹,获得了光致变色微球。在常温下,采用紫外-可见光谱对光致变色微球的变色性质及抗疲劳性进行了检测,并通过建立半数吸光度可逆变色循环次数参数Z50,将包裹了螺吡喃的微球与未包裹的螺吡喃溶液进行对比,发现包裹后的微球除了具备良好的光致变色性质外,其抗疲劳性亦远高于其溶液。     

镁基储氢材料催化的研究进展

过去十几年国内外对镁基储氢材料的催化剂研究表明,使用催化剂能够有效改善材料的表面特性,提高材料的吸放氢动力学性能。目前常用的催化剂体系有过渡族金属、金属氧化物、金属卤化物、金属间化合物以及碳素非金属。通过比较发现,不同种类的催化剂催化效果不同,相应的催化机理也有所差异。目前,国外研究者已发现几种催化剂共同催化的效果显著,国内应加强金属间化合物和碳素材料催化剂以及不同催化剂共同作用方面的研究。     

照相有机物结构鉴定

简述了有机化合物结构鉴定的常用程序。以照相有机物及其中间体为例，介绍了谱图综合解析在未知物结构鉴定中的应用。     

Valency relations between alkali and alkali earth elements and elements of second and third long periods

Abstract

Elements of groups IA and IIA form many compounds with elements of the third long period passing back from bismuth to platinum; fewer compounds are formed with elements of the second and earlier periods. The incidence of such compounds has been analysed graphically such that the valencies on the components may be inferred. The compounds exhibit low valency on the second/third long period component, and normal valency on the A-element. The compounds are covalent in character, and are formed across the ionic divide consistent with Fajans' rule.

MST/464     

Ab Initio Investigations of Structural,Elastic, Mechanical,Electronic, Magnetic,and Optical Properties of Half-Heusler Compounds RhCrZ (Z = Si,Ge)

The first principle study of half-Heusler compounds RhCrZ (Z = Si, Ge) is performed in the framework of density functional theory (DFT). The compounds are found to have small band gap in the minority spin channel (spin-down). While the majority spin channel (spin-up) is metallic. Therefore, both compounds are half-metallic and 100 % spin polarized at Fermi level. Several properties including structural, mechanical, elastic, electronic, magnetic, and optical are computed using the full potential linearized augmented plane wave (FP-LAPW) method as implemented in the WIEN2k simulation package. Equilibrium lattice constants for both compounds are found to be in the range 5.5–6.0 Å. Elastic properties indicate the ductile nature of the compounds. The total magnetic moments for these compounds are approximately equal to 1μ _B, i.e., M_Tot ≈ 1μ _B. Hence, the compounds are weak ferromagnetic materials. We have calculated the complex dielectric function. Many optical properties including reflectivity, refractive index, conductivity, and absorption coefficients are obtained form dielectric function. Imaginary part of the dielectric functions shows that compounds are optically metallic and become transparent above 17 and 13 eV, respectively. It is also observed that compounds are more active in the infrared region.     

Evaluation of biodegradation ranks of priority organic compounds

Biodegradations of 78 priority organic compounds were tested with an electrolytic respirometer under the standard conditions determined in the preceding paper. The biodegradabilities of these numerous compounds were classified into ten ranks by the method proposed in the preceding paper. The results are discussed from the structures of the organic compounds and conventional knowledge on the biodegradation mechanisms, and propriety of the classification method for evaluating the biodegradabilities are substantiated.     

金属间化合物的计算机模拟研究

简述了目前金属间化合物计算机模拟常用的第一原理方法和嵌入原子方法模型结合的分子动力学方法。综述了近年来金属间化合物晶体缺陷结构方面的计算机模拟研究成果。     

Prediction of heats of sublimation of nitroaromatic compounds via their molecular structure

This work presents a new approach to predict heats of sublimation of nitroaromatic compounds derived from their molecular structure information. The number of carbon, hydrogen and nitrogen atoms as well as the contribution of some specific groups attached to aromatic ring would be needed in the new method. Predicted heats of sublimation for 40 nitroaromatic compounds are compared with experimental data. Calculated results for some nitroaromatic compounds are also compared with complicated quantum mechanical computations of Rice et al. [B. M. Rice, S. V. Pai, J. Hare, Combust. Flame 118 (1999) 445] where computed outputs were available. The root mean square deviation (rms) from experiment for the predicted heats of sublimation of 40 compounds by new method is 7.78 kJ/mol with a maximum deviation of 18.52 kJ/mol. The rms deviations of new procedure and reported quantum mechanical method for six nitroaromatic compounds are 9.19 and 10.18 kJ/mol, respectively.     

The influence of chemical structure and combustion reactions on the maximum experimental safe gap of industrial gases and liquids

The paper shows how the molecular structure of a compound and the nature of the intermediates formed during its combustion can influence the Maximum Experimental Safe Gaps (MESGs). A qualitative discussion estimates the MESG of compounds for which measurements are not available by comparing their molecular structure and combustion products with those of compounds having measured MESGs. A list of compounds is given with measured MESGs corrected to standard temperature and pressure. The MESGs of compounds in various species groups are positioned on figures to show how molecular structure affects the MESG.     

Comparison of curing compounds to reduce volume change from differential drying in concrete pavement

Curing compounds are used to retain moisture which promotes hydration to develop a tight microstructure. Because of the large surface-to-volume ratio of these structures, differential moisture loss can cause unwanted deflections, reduction in ride quality, and cracking. This paper quantitatively compares the effectiveness of different curing methods with an emphasis on curing compounds to resist moisture loss and subsequent volume changes caused by differential shrinkage. This work provides a quantitative comparison between different curing compounds, wet, sealed and no curing not made in previous publications. A performance-based cost analysis over the different curing compounds is also included. The result shows that the poly-alphamethylstyrene curing compound causes the lowest mass loss and subsequent deflections compared to the water–resin and water–wax-based curing compounds at equal coverage rates at equal costs. The work also shows that a double application of curing compound shows greater benefit than a single layer with the same volume for water–wax-based curing compounds. The results show that if adequate amounts of curing compounds are used then they are a useful curing method for members sensitive to differential drying such as concrete pavements.     

Reduction of chemical formulas from the isotopic peak distributions of high-resolution mass spectra

A method has been developed for the reduction of the chemical formulas of compounds in complex mixtures from the isotopic peak distributions of high-resolution mass spectra. The method is based on the principle that the observed isotopic peak distribution of a mixture of compounds is a linear combination of the isotopic peak distributions of the individual compounds in the mixture. All possible chemical formulas that meet specific criteria (e.g., type and number of atoms in structure, limits of unsaturation, etc.) are enumerated, and theoretical isotopic peak distributions are generated for each formula. The relative amount of each formula is obtained from the accurately measured isotopic peak distribution and the calculated isotopic peak distributions of all candidate formulas. The formulas of compounds in simple spectra, where peak components are fully resolved, are rapidly determined by direct comparison of the calculated and experimental isotopic peak distributions. The singular value decomposition linear algebra method is used to determine the contributions of compounds in complex spectra containing unresolved peak components. The principles of the approach and typical application examples are presented. The method is most useful for the characterization of complex spectra containing partially resolved peaks and structures with multiisotopic elements.