Properties and Characterization of Modified HZSM—5 Zeolites

Physicochemical and catalytic properties of phosphorus and boron modified HZSM-5 zeolites treated with 100% steam at 673K were investigated.The acidity and distribution of acidic sites were studied by infrared spectroscopy using pyridine as probe molecule and temperature programmed desortion (TPD) of ammonia.The structure of the samples was characterized by XRD,and the textural properties of the catalysts were determined by nitrogen isothermal adsorption-desorption measurements and scanning electron microscopy(SEM).The XRD results show that the modified samples have no novel crystalline phase,indicating a high dispersion of phosphorus and boron species.After treatment,the microporous volume and surface area of the samples markedly decrease,implying the bolockage of the channel.The nitrogen adsorption-desorption measurements suggest that the isothermal type of all samples is a combination of isothermal type Ⅰ and Ⅳ，and all hysteresis loops resemble the H4-type in the IUPAC classification.The total acidity of the modified samples,determined by pyrldine adsorption IR and TPD of ammonia,decreases in contrast to that of the parent HZSM-5.The conversion of n-heptane over P and B steammodified HZSM-5 is higher than that of P and B-modified HZSM-5 zeolites but lower than that of the parent HZSM-5.     

Circularly Polarized Luminescence of Aluminum Complexes for Chiral Sensing of Amino Acid and Amino Alcohol

Determination of the absolute configuration (AC) of chiral molecules is a key issue in many fields related to chirality such as drug development, the asymmetric reaction screening, and the structure determination of natural compounds. Although various methods, such as X‐ray crystallography and NMR spectroscopy, are used to determine the AC, a simple and cheap alternative method is always anticipated. So far, electronic circular dichroism (ECD) spectroscopy has been widely used to ascertain the AC and enantiomeric excess (ee) values by applying appropriate organic probes. Here, circularly polarized luminescence (CPL) spectroscopy was applied to determine the AC and ee values of a series of amino acid and amino alcohol. The measurements were conducted by mixing the amino acids or amino alcohols with an achiral 1‐hydroxy‐2‐naphthaldehyde. Upon in situ formation of the Schiff base complexes, the system showed emission enhancement and CPL in the presence of Al³⁺, whose intensity and sign can be used to assign the chiral sense of the amino acids and amino alcohols. The authenticity of the method was further compared with the established CD spectroscopy, revealing that CPL spectra of formed Al³⁺ complex were effective to determine the AC of chiral species.     

Ab Initio Calculation of Room Temperature Ionic Liquid 1-Ethyl-3-Methyl-Imidazolium Chlorocuprate (Ⅰ)

The Hartree-Fock method has been employed to investigate the electronic structures of EMIM (1-ethyl-3-methyl-imidazolium ), CuCl2-, Cu2Cl3-, CuCl32-, EMIM -CuCl2-, EMIM -Cu2Cl3-,and EMIM -CuCl32- pairs. Full optimization and frequency analyses of EMIM , CuCl2-, Cu2Cl3-, CuCl32-,eight initial EMIM -CuCl2-, six EMIM -Cu2Cl3-, and four EMIM -CuCl32- geometries have been carried out using Gaussian-94 soft-package at 6-31 G(d,p) basis set level for hydrogen, carbon, nitrogen, chlorine atoms and Hay-Wadt effective core potential for copper atom. The electronic structures of lowest energy of EMIM -CuCl2-, EMIM -Cu2Cl3-, EMIM -CuCl32-, single EMIM , CuCl2-, Cu2Cl3-, and CuCl32- have been comparatively studied. The calculated results showed that EMIM -CuCl2- pair conformer of lowest energy was five ring parallel to Cl-Cu-Cl with 3.2 (A) distance, EMIM -CuCl32- pair conformer of lowest energy was five ring parallel to CuCl32-plane with 3.4 (A) distance, and the optimized EMIM -Cu2Cl3- pair conformer of lowest energy was five ring perpendicular to Cl-Cu-Cl-Cu-Cl plane with 3.0 (A) distance between the terminal Cl atoms and the 5-ring of EMIM . The cohesion between cations and anions analyses suggested that all stationary points are minimum because of no appearing of imaginary frequency.The assigned frequencies were in agreement with the experimental report. The low energy of interaction because of the bulky asymmetry of EMIM and the charge dispersion of cation and anion leads to the low melting point of the ionic liquids, EMIM -CuCl2-, EMIM -Cu2Cl3-, and EMIM -CuCl32-. The interaction energy of EMIM -CuCl2-, EMIM -Cu2Cl3-, and EMIM -CuCl32- is 309.0 k J/mol, 316.8 k J/mol, and 320.2 k J/mol, respectively. The relationship of interaction energy via distance between cations and anions was also investigated by single point energy scan.     

Stepwise Engineering the Pore Aperture of a Cage-like MOF for the Efficient Separation of Isomeric C4 Paraffins under Humid Conditions

The separation of isomeric C4 paraffins is an important task in the petrochemical industry, while current adsorbents undergo a trade-off relationship between selectivity and adsorption capacity. In this work, the pore aperture of a cage-like Zn-bzc (bzc=pyrazole-4-carboxylic acid) is tuned by the stepwise installation methyl groups on its narrow aperture to achieve both molecular-sieving separation and high n-C₄H₁₀ uptake. Notably, the resulting Zn-bzc-2CH₃ (bzc-2CH₃=3,5-dimethylpyrazole-4-carboxylic acid) can sensitively capture n-C₄H₁₀ and exclude iso-C₄H₁₀, affording molecular-sieving for n-C₄H₁₀/iso-C₄H₁₀ separation and high n-C₄H₁₀ adsorption capacity (54.3 cm³ g⁻¹). Breakthrough tests prove n-C₄H₁₀/iso-C₄H₁₀ can be efficiently separated and high-purity iso-C₄H₁₀ (99.99 %) can be collected. Importantly, the hydrophobic microenvironment created by the introduced methyl groups greatly improves the stability of Zn-bzc and significantly eliminates the negative effect of water vapor on gas separation under humid conditions, indicating Zn-bzc-2CH₃ is a new benchmark adsorbent for n-C₄H₁₀/iso-C₄H₁₀ separation.     

铁电畴夹层结构中声致发光的探讨

由4mm铁电半导体构成的铁电180°畴夹层结构,在超声波的激发下有铁电畴层波产生。铁电畴层波的电势场使电子和空穴不断地分离与复合而辐射光脉冲,将超声波能量转化为光能。调节超声波,可改变光脉冲的强度和周期。     

水中爆炸加载金属板变形的实验研究

本文给出了研究抛体大变形的光学实验测试方法,用该方法测定了水中爆炸作用下的金属板的变形过程,得到了金属板上任意点随时间变化的位移曲线和速度曲线以及金属板变形过程的真实位移场。该方法比常用的测量抛体运动速度的电测探针法前进了一步。     

Anti-arthritic and cartilage damage prevention via regulation of Nrf2/HO-1 signaling by glabridin on osteoarthritis

Osteoarthritis is a common degenerative disease linked with inflammatory disorders and oxidative stress. Glabridin is an isoflavonoid and major active constituent of licorice. This study aims to investigate the anti-arthritic effects of glabridin on nuclear factor erythroid 2 – related factor 2 (Nrf2) signaling pathway, inflammatory responses, and cartilage degeneration in in-vitro and in-vivo models. Studies on IL-1β-induced chondrocyte model was performed to evaluate matrix metalloproteinase (MMP), Nrf2 signaling pathway. Glabridin was orally administered in monosodium-iodoacetate (MIA)-induced osteoarthritic (OA) rats for in-vivo evaluation. Pain and swelling of limbs were observed, oxidative stress markers and inflammatory cytokines were measured. Histomorphological changes in the joint cartilage were analyzed. Glabridin significantly reduced the arthritic score and paw swelling along with improved body weight, and organ index of rats. Histopathological score showed significant prevention of joint cartilage degeneration by glabridin. Expressions of TNF-α, IL-6, IL-10, and IL-1β were attenuated by glabridin (p < 0.05) in MIA-induced rats. Protein expressions of iNOS, COX-2, ADAMTS5, MMP-3, and MMP-13 were suppressed (p < 0.05) whereas the Nrf2/HO-1 signaling was activated by glabridin (p < 0.05) in osteoarthritic chondrocytes. Therefore, anti-arthritic and chondroprotective activity of glabridin is suggested by the inhibition of MMP expression and regulation of Nrf2/HO-1 signaling.     

增强型电场协助光催化降解有机污染物

以颗粒状ＴｉＯ２为光催化剂,以工苯酚溶液的降解为模型反应,实现了在电场协助下三维光电组合仙化反应,实验发现,在相同的反应条件下,电解反应和光催化反应中苯酚的降解率分别为１０％和３３．６％,而光电组合催化过程中苯酚的降解率为８２．８％,存在明显的协同作用,产生这种协同作用的主要原因是,电解水反应可有效地为光催化反应提供氧源,以及阳极偏压可有效地减少光生电子和空穴的复合,此外,还研究了电量和溶液酸碱性     

可持续发展理念下的中学化学教师教育

论述了中学化学教师教育是教师自身可持续发展的战略需要.同时对可持续发展的持续性、整体性、协调性与中学化学教师教育的关系尤其是在可持续发展思想指导下,如何建立中学化学教师教育的课程进行了阐述.     

Helical Nanostructures: Chirality Transfer and a Photodriven Transformation from Superhelix to Nanokebab

Photosensitive cinnamic acid conjugated glutamides were designed to demonstrate photocontrolled hierarchical chirality transfer and switching in self‐assembled systems. In methanol, the cinnamic acid derivatives self‐assembled into superhelices, which could be switched into nanokebabs upon UV irradiation. These two nanostructures showed opposite helicity. The chiral nanostructures could further convey their chirality to achiral fluorescent molecules and result in the emission of circularly polarized luminescence (CPL). Remarkably, the CPL followed the helicity of the chiral nanostructure rather than the inherent molecular chirality. Photodriven dimerization of the cinnamic moiety lead to a significant change in molecular packing and subsequent switching of the helicity of the formed nanostructures.