Solvothermal synthesis,thermal and adsorption properties of metal-organic frameworks Zn and CoZn(DPB)

Journal of Thermal Analysis and Calorimetry - New mononuclear and hetero-binuclear MOFs derived from the reaction of 1,4-bis[(3,5-dimethyl)pyrazole-4-yl]benzene (H2DPB) with zinc nitrate or mixture...     

Comparative essential oil composition of aerial parts of Tanacetum dumosum Boiss. from Southern Zagros,Iran.

The essential oils of leaves and flowers of Tanacetum dumosum Boiss., an endemic medicinal shrub, were extracted by using hydrodistillation method and analysed using GC and GC–MS. A total of 43 and 44 compounds were identified in the essential oils from the leaves and flowers of T. dumosum, respectively. The major chemical constituents of leaves oil were borneol (27.9%), bornyl acetate (18.4%), 1,8-cineol (17.5%), α-terpineol (5.3%), cis-chrysanthenyl acetate (3.3%), camphene (2.7%) and terpinene-4-ol (1.9%), while the main components of the flower oil were isobornyl-2-methyl butanoate (41.1%), trans-linalyl oxide acetate (11.9%), 1,8-cineole (7.7%), thymol (4.2%), linalool (3.9%), camphor (2.9%), isobornyl propanoate (2.9%), α-terpineol (2.1%) and caryophyllene oxide (2.0%). Major qualitative and quantitative variations for some main chemical compounds among different aerial parts of T. dumosum were identified. High contents of borneol, bornyl acetate, 1,8-cineol and linalool in the leaves and flowers of T. dumosum show its potential for use in the food and perfumery industry.     

Self‐Healing Materials from V‐ and H‐Shaped Supramolecular Architectures

Integrating self‐healing capability into supramolecular architectures is an interesting strategy, and can considerably enhance the performance and broaden the scope of applications for this important class of polymers. Herein we report the rational design of novel V‐shaped barbiturate (Ba) functionalized soft–hard–soft triblock copolymers with a reversible supramolecular healing motif (Ba) in the central part of the hard block, which undergoes autonomic repair at 30 °C. The designed synthesis also offers a suitable macromolecular building block to further self‐assemble with heterocomplementary α,ω‐Hamilton wedge (HW) functionalized polyisoprene (PI; HW‐PI‐HW), resulting in an H‐shaped supramolecular architecture with efficient self‐healing capabilities that can recover up to around 95 % of the original mechanical performance at 30 °C within 24 h.     

Purification and Characterization of the Xylanase Produced by Jonesia denitrificans BN-13

Jonesia denitrificans BN-13 produces six xylanases: Xyl1, Xyl2, Xyl3, Xyl4, Xyl5, and Xyl6; the Xyl4 was purified and characterized after two consecutive purification steps using ultrafiltration and anion exchange chromatography. The xylanase-specific activity was found to be 77 unit (U)/mg. The molecular weight of the Xyl4 estimated using sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) revealed a monomeric isoenzyme of about 42 kDa. It showed an optimum pH value of 7.0 and a temperature of 50 °C. It was stable at 50 °C for 9.34 h. The enzyme showed to be activated by Mn⁺², β-mercaptoethanol, and dithiothreitol (DTT) with a high affinity towards birchwood xylan (with a K _m of 1 mg ml^?1) and hydrolysis of oat-spelt xylan with a K _m of 1.85 mg ml^?1. The ability of binding to cellulose and/or xylan was also investigated.     

Ar^＋, He^＋，S^＋离子轰击n-InP单晶表面的机理研究

通过X射线光电子能谱和低能电子衍射实验研究了10～180 eV的Ar＋、 He＋、S＋离子轰击n-InP（100）表面, 发现S＋离子轰击可以产生In-S组分,减轻离子轰击对表面的物理损伤.对于Ar＋离子轰击后的表面,经过S＋离子处理和加热过程以后,表面损伤得到了修复,最终得到了2×2的InP表面,进一步验证了S＋离子对InP表面的修复作用.     

Appended corrole manganese complexes:Catalysis and axial-ligand effect

A series of N-base appended corroles and their manganese complexes were synthesized and their binding constants with three different nitrogenous ligands, triethylamine, N-methylimidazole and pyridine, were evaluated by spectroscopy. Kinetic studies indicated that the presence of appended N- donor ligands may cause a significant enhancement of the rate of oxygen atom transfers （OAT） from （oxo）manganese（V） corrole to alkene, and the stronger axial ligand binding has impact on the rate of the oxidation reaction. Turnover frequency （TOF） for the catalytic oxidation of alkenes by appended manganese corroles varies with the following ligand order： acetamido 〈 pyridyl 〈 imidazolyl. The influence of the external axial ligands on the catalytic epoxidation was investigated by using appended acetamido manganese corrole as catalyst, with the results revealing that N-methylimidazole gave the best enhancement on the yields of total oxidation products among the investigated nitrogenous ligands.     

Fabrication of NiO coated SiO2 and SiO2 coated NiO for the removal of Pb2＋ ions

We have prepared silica,SiO2coated NiO and NiO coated SiO2by sol-gel method.The physicochemical properties of the desired materials were investigated by surface charge properties,scanning electron microscopy（SEM）,energy dispersive X-ray（EDX） spectroscopy,surface area measurements and X-ray diffraction（XRD） analyses.The point of zero charge（PZC） of the solid was determined by the salt addition method.In coated materials,two PZC values were noted representing the surface charge of their counterparts.The SEM image of SiO2coated NiO displays a uniform coating of silica on the surface of NiO whereas in case of NiO coated SiO2,a honeycomb like appearance was observed with highly porous structures.In the diffractograms of NiO,the characteristic peaks were suppressed in NiO coated silica however,no diffraction peak could be seen in SiO2coated NiO.Batch adsorption technique was applied for the removal of Pb2＋ions from aqueous solution.The sorption trend for Pb2＋ions was observed in the order of NiO coated SiO2〉 SiO2coated NiO 〉 NiO 〉 SiO2.This trend confirms that the coated materials have more sorption capacities than their parent counterparts.     

Ag/Ag3PO4/g-C3N4三元复合光催化剂的制备及其可见光驱动下的光催化活性增强

报道了一种新型Ag/Ag₃PO₄/g-C₃N₄三元复合光催化剂的制备及其半导体界面处的快速载流子分离所引起的光催化活性的显著增强效应。通过X射线衍射,扫描电子显微镜,紫外-可见吸收光谱以及光致发光光谱等就其晶体结构、形貌、组分、光学吸收以及载流子的快速分离行为进行了表征与分析。以罗丹明B作为模型化合物分子,研究发现,所制备的Ag/Ag₃PO₄/g-C₃N₄三元复合光催化剂在可见光照射下表现出比Ag₃PO₄以及Ag₃PO₄/g-C₃N₄二元催化剂更为优异的光催化活性。研究认为,Ag₃PO₄表面尺寸约为40 nm的Ag纳米粒子在可见光下受激所产生的等离子表面共振效应以及Ag₃PO₄与g-C₃N₄界面处所形成的类似异质结结构对所制备的Ag/Ag₃PO₄/g-C₃N₄三元复合光催化剂光催化活性的显著增强起到重要作用。