Copper complexes within the supramolecular solid structure of cyanuric acid and melamine

A complex of copper sulfate was formed by impregnation of the cyanuric acid melamine adduct (CAM) with a solution of copper (II) sulfate. A thermal treatment at 250°C of the dried compound delivered a greenish powder. The UV-Vis spectroscopy showed that an absorption around 700 nm is compatible with a copper (II) sulfate complex coordinated inside the supramolecular structure of CAM. No copper or copper oxide particles were found by means of either transmission or scanning electron microscopy. X-ray photoelectron spectroscopy showed that on the surface there was a considerable amount of Cu(I) (66%) probably coordinated also inside the CAM channels. A brief catalytic test showed the ability of the copper complexes to oxidize sucrose to gluconic acid.     

Consequences of molecular strain on the solid state addition reaction

An overview is given on the solid-state addition reaction under mechanical stressing. Enhanced charge transfer across the boundary of dissimilar chemical species was observed mainly in terms of local polarization and/or radical formation. Associated anomaly of electron distribution is regarded mainly as a consequence of broken symmetry at various levels, i.e. molecular orbitals, crystal fields or ligand fields. A new preparation method of some ferrous coordination compounds is demonstrated. Recent preliminary results on some organic addition reactions are then displayed. Mechanisms of organic adduct formation via a series of Diels-Alder reactions are speculated. Outlook towards a new possibility of mechanochemical reactions in the direction of organic synthesis are also given.     

The structure and mechanical properties of polyoxymethylene polymerized in the solid state

Polyoxymethylene specimens with single crystal texture were produced by irradiation of needle-shaped trioxane crystals subsequently post-polymerized at fixed temperatures between 30 and 60°C. A clear dependence of polymer conversion on irradiation dose and polymerization temperature was revealed. The polymer morphology consisted of mutually aligned fibrils, half of which were chain-extended crystallites with their molecular axes coincident with the specimen axis. The remaining fibrils consisted of folded chains in a “twin” configuration. The degree of order in the specimens was analysed in terms of the arcing of X-ray diffraction spots. There existed an intrinsic level of misorientation of molecules which depended on the post-polymerization temperature, plus a misalignment due to displacement of fibrils on the removal of unreacted monomer. Finally, the mechanical properties were investigated and the Young's modulus was found to approach closely its theoretical limit at the conversion maximum. The results are interpreted on the basis of a simple morphological model.     

PE100管材料的聚集态结构和性能的固体NMR分析

PE100管材料基体树脂中界面区的含量比较高(高于10%),而完全无定形区的含量极低.界面区含量表征非晶区中运动部分受阻的链段所占的比重,因而上述结果意味着PE100管材料中非晶区中链段表现出强烈的缠结倾向.界面区的含量(或非晶区的组成特征)决定了材料的耐慢速裂纹增长性能,而固相区含量则决定了材料的力学强度,两种影响因素的平衡决定了最终管材料的长期使用性能.     

Using magnetic birefringence to determine the molecular arrangement of supramolecular nanostructures

Abstract

Supramolecular aggregates can be aligned in solution using a magnetic field. Because of the optical anisotropy of the molecular building blocks, the alignment results in an anisotropic refractive index of the solution parallel and perpendicular to the magnetic field. We present a model for calculating the magnetic birefringence, using solely the magnetic susceptibilities and optical polarizabilities of the molecules, for any molecular arrangement. We demonstrate that magnetic birefringence is a very sensitive tool for determining the molecular organization within supramolecular aggregates.     

Using magnetic birefringence to determine the molecular arrangement of supramolecular nanostructures

Supramolecular aggregates can be aligned in solution using a magnetic field. Because of the optical anisotropy of the molecular building blocks, the alignment results in an anisotropic refractive index of the solution parallel and perpendicular to the magnetic field. We present a model for calculating the magnetic birefringence, using solely the magnetic susceptibilities and optical polarizabilities of the molecules, for any molecular arrangement. We demonstrate that magnetic birefringence is a very sensitive tool for determining the molecular organization within supramolecular aggregates.     

Solid state properties and molecular structure of some divalentnd10 cation-TCNQ salts

The electrical behaviour of the divalentnd¹⁰ cation-tetracyanoquinodimethane (TCNQ) salts (mercury, zinc and cadmium) has been investigated in the temperature range 300–400 K at a constant pressure of 100 kbar cm^–2. The electrical resistivity measurements show a phase transition at nearly 338 and 223 K for Zn(TCNQ)₂ and Hg(TCNQ)₂, respectively. Collesions between the elucidated structure obtained from the infrared and ultraviolet spectra and the electrical properties of these salts are considered. The activation energy of conductance has been calculated. Further information concerning the electrical behaviour is obtained by considering the type and mechanism of the conduction process. This has been achieved by studying the effect of complex formation and temperature on the mobility of the charge carriers and their production.     

分子流状态平面密封结构漏率预估

本文结合Roth模型建立了分子流状态下的漏率计算模型,得出了平面密封泄漏漏率与密封力 矩、密封面粗糙度之间的对应关系,同时还给出为保证分子流状态,密封力矩、密封面粗糙度应满足的条件.在理论计算的同时,还通过实验证明了漏率预估方法的准确性.     

纳米硫化锌的制备及助燃性能

以NaCl,HOCH2CH2OH和（CHa）2CHOH为分散剂,用固相法在室温合成了纳米硫化锌,用紫外吸收光谱,红外光谱和氮气吸附等方法对纳米硫化锌粉体的结构,组成,平均粒径和比表面积等进行了表征,研究了分散剂和温度等因素对纳米硫化锌粉体的性能以及纳米硫化锌对重油-煤-水三元混合流体燃烧性能的影响．结果表明：加入适量的分散剂和表面活性剂,在室温用固相法能够制备出分散性好的单一立方相纳米硫化锌．在其紫外吸收光谱中纳米硫化锌吸收峰蓝移,并具有红外透明性．纳米硫化锌作为助燃剂添加到重油-煤-水三元混合流体燃料燃中,能够明显提高重油-煤-水三元混合流体的燃烧性能.     

Dissolution and bioavailability enhancement of alpha-asarone by solid dispersions via oral administration

Alpha (α)-asarone (1-propenyl-2,4,5-methoxybenzol) (ARE) has been extensively used to treat chronic obstructive pulmonary diseases (COPD), bronchial asthma, pneumonia, and epilepsy. Due to its poor solubility and bioavailability, ARE was clinically administered via intravenous injection. However, severe allergies were often reported due to the presence of solublizers in the injection formulation. In our study, we sought to explore the biopharmaceutical classification of ARE, elucidate the mechanisms behind ARE absorption, and to develop a viable formulation to improve the oral bioavailability of ARE. ARE was not a P-glycoprotein substrate, which was absorbed in the passive mode without site specificity in the gastrointestinal tract. Solid dispersions prepared using hydrophilic matrix materials such as Pluronic F68, and polyethylene glycol (PEG) of varying molecular weights (PEG4K, PEG10K, and PEG20K) were proven to significantly improve the dissolution of ARE in vitro and the oral bioavailability of ARE in rats, which represent a promising strategy for the oral administration of ARE and other BCS II compounds.     

固相反应法制备纳米铈锆复合氧化物

以碳酸铈、碳酸锆、草酸为原料,机械力促进固相反应法制备了纳米级铈锆复合氧化物(CexZr1-XO2)。用TGDSC分析前驱体的热分解温度,通过XRD、TEM、BET等测试手段对产物进行了表征。结果表明:所得产物为单一的立方晶系固溶体,平均粒径<40nm,比表面积达98m2/g。采用中低温固相反应法制备纳米级铈锆复合氧化物无需溶剂,无废液且节能。     

Changes of symmetry in the structure of SrCeO3 -BaZrO3 solid solution

The structural behaviour of SrCeO₃ -BaZrO₃ solid solution was determined and the crystal constants were calculated from X-ray diffraction data. Several displacive changes of symmetry were detected, related to distortion introduced by Sr and Ce atoms in the perovskite framework of the solid solution. Deviation from Vegard's law was observed and related to structure changes.     

Structural and electrical properties of V-doped ZnO prepared by the solid state reaction

This paper reports the synthesis, crystal structure and electrical conductivity properties of vanadium (V)-doped zinc oxide (ZnO) powders (i.e. Zn_1?2X V _X O binary system, x = 0, 0.0025, 0.005, 0.0075 and in the range 0.01 ≤ x ≤ 0.15). I-phase samples, which were indexed as single phase with a hexagonal (wurtzite) structure in the V-doped ZnO binary system, were determined by X-ray diffraction (XRD). The limit solubility of V in the ZnO lattice at this temperature is 3 mol % at 950 °C. The impurity phase at 950 °C was determined as ZnV₂O₆ when compared with standart XRD data. The research focused on single I-phase ZnO samples which were synthesized at 950 °C because of the limit of the solubility range is widest at this temperature. It was observed that the lattice parameters a and c decreased with V doping concentration. The electrical conductivity of the pure ZnO and single I-phase samples were studied using the four-point probe dc method at temperatures between 100 and 950 °C in an air atmosphere. The electrical conductivity values of pure ZnO and 3 mol % V-doped ZnO samples at 100 °C were 2.75 × 10^?6 and 7.94 × 10^?5 Ω^?1 cm^?1, and at 950 °C they were 3.4 and 54.95 Ω^?1 cm^?1, respectively. In other words, the electrical conductivity increased with V doping concentration.     

Group-theoretic approach to the enhancement of the Fourier modal method for crossed gratings: C2 symmetry case

A new formulation of the Fourier modal method for crossed gratings with symmetry considerations is established by using the group-theoretic approach that we have developed recently. Considering crossed gratings with the C2 symmetry (invariance after rotation about the normal of the mean grating plane through angle pi), we present in detail the construction of the new algorithm, illustrate the improved computation efficiency, and discuss its application. It is shown theoretically and numerically that when the grating is Littrow mounted and the truncated reciprocal lattice of the diffracted field also has the C2 symmetry, the maximum effective truncation number of the algorithm is doubled and the computation time is reduced by a factor of 4. The time saving factor is increased to 8 for the special case of normal incidence.