Tautomerism and Acidic Properties of N‐Unsubstituted Benzohydroxamic Acids: Semiempirical Quantum Chemical Estimation

Tautomerism of Nunsubstituted benzohydroxamic acids and their anions in the gas phase was investigated by the semiempirical AM1 method. The possibility of estimating pK _a in aqueous solutions using calculated characteristics of molecules is demonstrated.     

C→N Migrations of the ethoxycarbonyl group in reactions of ortho-substituted aryl isocyanates with the 1,3-zwitterion derived from triisopropylphosphine and ethyl 2-cyanoacrylate

The reactions of meta—para-substituted aryl isocyanates with phosphorus-containing 1,3-zwitterions, which proceed with the CN migration of the CO₂Et group to form the corresponding carbamates, were extended to ortho-substituted aryl isocyanates. The influence of the steric and electronic effects of the ortho substituents in the aromatic rings of aryl isocyanates on the ease of this rearrangement is qualitatively considered.     

Asymmetric reduction of acetophenone and propiophenone by NaAl(IPTOLate)H2 combined with enantiomeric enrichment of the reaction product as an inclusion complex with IPTOL

An improved procedure was developed for asymmetric reduction of acetophenone and propiophenone by the chiral reagent NaAl(IPTOLate)H₂. This procedure is based on isolation of the chiral alcohol that formed as a crystalline host—guest complex with the IPTOL ligand. The enantiomeric enrichment of the product was as high as 97% ee. The ability of IPTOL and its analogs to form host—guest complexes with a number of ether-type solvents, 1-phenylethanol, and 1-phenylpropan-1-ol as well as thermal stabilities of IPTOL-containing complexes with these alcohols were studied.     

材料化学实验课程体系的改革与建设

结合材料化学实验课程自身的特点及材料化学实验教学的经验，系统阐述我院材料化学实验改革的思路，通过深化材料化学实验教学改革，提高任课教师的学术水平，更新教学内容，优化教学模式，推进教材的系统性建设，实现材料化学实验教学质量的提高，激发学生的学习热情与兴趣，进一步培养学生的创新能力。     

Altered Lipid Composition of Secretory Cells Following Exposure to Zinc Can Be Correlated to Changes in Exocytosis

A micromolar concentration of zinc has been shown to significantly change the dynamics of exocytosis as well as the vesicle contents in a model cell line, providing direct evidence that zinc regulates neurotransmitter release. To provide insight into how zinc modulates these exocytotic processes, neurotransmitter release and vesicle content were compared with single cell amperometry and intracellular impact vesicle cytometry with a range of zinc concentrations. Additionally, time-of-flight secondary ion mass spectrometry (ToF-SIMS) images of lipid distributions in the cell membrane after zinc treatment correlate to changes in exocytosis. By combining electrochemical techniques and mass spectrometry imaging, we proposed a mechanism by which zinc changes the fusion pore and the rate of neurotransmitter release by changing lipid distributions and results in the modulation of synaptic strength and plasticity.     

A New Small-Molecule Donor Containing Non-Fused Ring π-Bridge Enables Efficient Organic Solar Cells with High Open Circuit Voltage and Low Acceptor Content

To achieve high open-circuit voltage (V_oc) and low acceptor content, the molecular design of a small-molecule donor with low energy loss (E_loss) is very important for solution-processable organic solar cells (OSCs). Herein, we designed and synthesized a new coplanar A−D−A structured organic small-molecule semiconductor with non-fused ring structure π-bridge, namely B2TPR , and applied it as donor material in OSCs. Owing to the strong electron-withdrawing effect of the end group and the coplanar π-bridge, B2TPR exhibits a low-lying highest occupied molecular orbital and strong crystallinity. Furthermore, benefiting from the coplanar molecular skeleton, the high hole mobility, balanced charge transport and reduced recombination were achieved, leading to a high fill factor (FF). The OSCs based on B2TPR : PC₇₁BM blend film (w/w=1 : 0.35) demonstrates a moderate power conversion efficiency (PCE) of 7.10 % with a remarkable V_oc of 0.98 V and FF of 64 %, corresponding to a low fullerene content of 25.9 % and a low E_loss of 0.70 eV. These results demonstrate the great potential of small-molecule with structure of B2TPR for future low-cost organic photovoltaic applications.     

Nano-bio interface study between Fe content TiO2 nanoparticles and adenosine triphosphate biomolecules

The advent of nano-biotechnology has inspired the interface interaction study between engineered nanoparticles (NPs) and biomolecules. The interaction between Fe content titanium dioxide (TiO₂) NPs and adenosine triphosphate (ATP) biomolecules has been envisioned. The effect of Fe content in TiO₂ matrix was studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The increase in Fe content caused a decrease in particle size with change in morphology from spherical to one-dimensional rod structure. The Fe incorporation in the TiO₂ matrix reduced the transition temperature from anatase to rutile (A-R) phase along with formation of haematite phase of iron oxide at 400°C. The interaction of Fe content TiO₂ NPs with ATP molecule has been studied using spectroscopic method of Raman scattering and infrared vibration spectrum along with TEM. Fe content in TiO₂ has enhanced the interaction efficiency of the NPs with ATP biomolecules. Raman spectroscopy confirms that the NPs interact strongly with nitrogen (N₇) site in the adenine ring of ATP biomolecule. Engineering of Fe content TiO₂ NP could successfully tune the coordination between metal oxide NPs with biomolecules, which could help in designing devices for biomedical applications.     

Effect of vinyl acetate content and electron beam irradiation on the flame retardancy, mechanical and thermal properties of intumescent flame retardant ethylene-vinyl acetate copolymer

Ethylene vinyl acetate copolymer (EVA) flame retarded by ammonium polyphosphate (APP) and pentaerythritol (PER) was cross-linked by electron beam irradiation. The effects of vinyl acetate content and electron beam irradiation on the flame retardancy, mechanical and thermal properties of EVA composites were investigated. The volatilized products of EVA/APP/PER composites were characterized by thermogravimetric analysis/infrared spectrometry. As VA content increased, the volatilized products increased in the second decomposition step, but decreased in the third decomposition step. For all samples, the increase of irradiation dose could improve both the gel content and the Limit Oxygen Index (LOI, the minimum oxygen concentration by volume for maintaining the burning of a material) values of irradiated composites. The mechanical and thermal properties of the irradiated EVA composites were also evidently improved at appropriate irradiation dose as compared with those of unirradiated EVA composites, whereas these properties decrease at higher irradiation dose because of the electron beam irradiation-induced oxidative degradation or chain scission.     

GTSP重钙工艺减少反应料浆含水量的初步研究

1 引言 我国耕地严重缺磷的面积所占比例高达2/3,而目前施肥的磷/氮比例又远远低于国际平均水平,如此的比例失调将严重影响农业增产.在当前施用的磷肥中,普钙和重钙占了很大的比例.由于重钙是用磷酸而非硫酸酸解磷矿,所以不含硫酸钙杂质,有效五氧化二磷的含量也由16～21%提高到45～52%,肥效比普钙提高两到三倍.为此国家"八五"重点项目引进了Hy dro GTSP工艺2×40万吨/年重钙装置.该装置于1999年3月试车以来难以达到满负荷生产. 作者通过对生产工艺各环节的分析,指出反应料浆含水量偏高是影响装置生产负荷的主要因素.料浆中水分的重要来源之一是二次球磨.