亚微米和纳米氧化锌对蝌蚪生长发育的影响

采用短期水体暴露方式,初步探讨亚微米和纳米氧化锌对蝌蚪生长发育的影响。150只发育至相同时期的幼年蝌蚪,随机分为3组:对照组、200nm氧化锌暴露组和30nm氧化锌暴露组。分别添加5mg 200nm和30nm氧化锌至1L水中,进行暴露实验。本研究通过测定蝌蚪的重量、观察蝌蚪尾部组织形态及测定蝌蚪对Zn的吸附量,探讨亚微米和纳米氧化锌对蝌蚪胚后发育的影响。结果发现,对照组与暴露组在蝌蚪重量方面没有显著性差异(P>0.05),但两氧化锌暴露组之间差异显著(P<0.05);H&E染色观察蝌蚪尾部组织形态发现,ZnO水体暴露可引起蝌蚪一定程度上的组织病变。此外,200和30nm氧化锌暴露组中蝌蚪对Zn的吸附量显著高于对照组(P<0.05),但两氧化锌暴露组之间差异不显著(P>0.05)。更多还原     

3,5—二溴—4—氨基苯基荧光酮与钨显色反应的研究及应用

研究了在表面活性剂CTMAB存在下,钨与3,5-二溴-4-氨基苯基荧光酮形成配合物的显色反应和光度性质,在HCl 0.2～0.8mol·L~(-1)介质中,波长为523nm处测得配合物的表观摩尔吸光系数为1.21×10~5,钨含量在0～12μg/25ml范围内符合比耳定律。体系灵敏度较高,大多数常见阳离子不干扰钨的测定,拟定方法用于合金钢中微量钨的测定,结果满意。     

稀土氧化物上COS还原SO_2脱硫反应及机理

设计了两级干法脱硫系统，在第一级脱硫器中用ＣＯ还原烟道气中的ＳＯ２，在第二级脱硫器中，让在第一级脱硫器中产生的副产物ＣＯＳ与未完全脱除的ＳＯ２进一步进行二级脱硫反应。考察了稀土氧化物对ＣＯＳ还原ＳＯ２脱硫反应的催化活性，发现氧化铈具有最高的脱硫活性，并且具有较大的反应物配比适用范围。对氧化铈催化ＣＯＳ还原ＳＯ２反应提出了ｒｅｄｏｘ还原氧化机理。     

NiMoNx/γ-Al2O3催化剂的制备及加氢脱氮性能

采用程度升温氮化（ＴＰＮ）的方法制备了ＮｉＭｏＮｘ／γ－Ａｌ２Ｏ３催化剂，考察了它对吡啶加氢脱氮（ＨＤＮ）反应的催化活性。结果表明，ＮｉＭｏＮｘ／γ－Ａｌ２Ｏ３催化剂的活性远远高于ＮｉＭｏＳｘ／γ－Ａｌ２Ｏ３催化剂和工业硫化态催化剂。对于ＮｉＭｏＺｘ／γ－Ａｌ２Ｏ３催化剂，助剂Ｎｉ的作用与硫化物体系中的Ｎｉ不同，它不仅是活化氢中心，同时也是脱氮中之心一，ＮｉＭｏＮｘ／γ－Ａｌ２Ｏ３催化剂的ＨＤＮ活     

无铬CO高温变换催化剂的研究 Ⅱ.过渡元素对高变催化剂结构与性能的影响

通过XRD,BET和XPS表征及反应性能测定表明,铁系高变催化剂中加入的过渡元素能够进入Fe3O4晶格形成固溶体,并使催化剂的晶胞参数随着加入元素离子半径的增大而增大,晶粒度明显变小,比表面积增大,起到铬的作用,催化剂的活性和热稳定性提高.发现部分过渡元素具有富集OH-的特性,使催化剂在较低的汽/气比条件下具有较高的催化活性.研制成功的B121型无铬高变催化剂性能达到铁铬系高变催化剂的技术指标.     

Diastereoselective Synthesis of Monofluorocyclohexenes through Photocatalyzed Cascade Cyclization of gem-Difluoroalkenes and α,β-Unsaturated Carbonyl Compounds

Monofluoroalkenes are nonhydrolyzable mimetics of amides. Previous work focused on the synthesis of non-cyclic monofluoroalkenes. However, diastereoselective synthesis of monofluorocyclohexenes from non-cyclic substrates is challenging. Herein, we report the first photocatalyzed cascade cyclization reactions of readily available α,β-unsaturated carbonyl compounds and gem-difluoroalkenes for the synthesis of highly functionalized monofluorocyclohexenes. The reaction shows broad substrate scope with high diastereoselectivity (>30 examples, up to 86 % yield, >20 : 1 dr). The post-reaction transformations of the products demonstrate the synthetic potential of this methodology.     

Breaking the Size Limitation of Directly-Synthesized PbS Quantum Dot Inks Toward Efficient Short-wavelength Infrared Optoelectronic Applications

PbS quantum dots (QDs) are promising building blocks for solution-processed short-wavelength infrared (SWIR) devices. The recently developed direct synthesis of semi-conductive PbS QD inks has substantially simplified the preparation processing and reduced the material cost, while facing the challenge to synthesize large-size QDs with absorption covering the SWIR region. Herein, we for the first time realize a low-cost, scalable synthesis of SWIR PbS QD inks after an extensive investigation of the reaction kinetics. Finally, based on these PbS SWIR QD inks, the solar cell demonstrates a record-high power conversion efficiency (PCE) of 1.44 % through an 1100 nm cutoff silicon filter and the photodetector device shows a low dark current density of 2×10⁻⁶ A cm⁻² at −0.8 V reverse bias with a high external quantum efficiency (EQE) of 70 % at ≈1300 nm. Our results realize the direct synthesis of low-cost and scalable SWIR QD inks and may accelerate the industrialization of consumer SWIR technologies.     

A new intumescent flame‐retardant: preparation,surface modification,and its application in polypropylene

Melamine salt of tripentaerythriol phosphate (MTP), as a new intumescent flame‐retardant, was prepared from tripentaerythritol (TPE), polyphosphoric acid, phosphoric pentoxide, and melamine, and then incorporated into polypropylene (PP) to obtain flame‐retarded PP‐MTP. FT‐IR analysis showed that MTP was in the form of cage structure. The flammability, combustion behavior, and thermal degradation and stability of flame‐retarded PP were characterized by using LOI, UL‐94 test, cone calorimetry, and TGA, respectively. By SEM, the char structure of PP‐MTP was analyzed. XRD diffraction tests showed that PP‐matrix of PP‐MTP presented better crystallized phases, when MTP was modified by methyl hydrogen siloxane. The relations of the dispersion of MTP in PP matrix to the compatibility between PP and MTP, and to the flame retardancy were discussed. Copyright © 2008 John Wiley & Sons, Ltd.     

Hydrogenation–dechlorination of 2-chloro-4,6-dinitroresorcinol over Pd/C catalysts

Research on Chemical Intermediates - Pd catalysts supported on active carbon (Pd/C) prepared by impregnation–deposition were used in catalytic hydrogenation and hydrodechlorination (HDC) of...     

Development of an Efficient Solid-Phase Microextraction Monolithic Column for the Analysis of Estrogens in Human Urine and Serum Samples

Estrogen plays a crucial role in various stages of human development and is present in the human body at trace level; therefore, an efficient strategy for the quantitative analysis of trace estrogens is required. However, this analysis is complicated by the presence of extremely complex biological matrices. To address this challenge, a novel method based on monolithic column solid-phase microextraction and ultra-high-performance liquid chromatography-tandem mass spectrometry was developed for the sensitivity analysis of six estrogens: β-estradiol, α-estradiol, 17α-ethynylestradiol, estrone, diethylstilbestrol, and hexestrol, in human urine and serum samples. The method exhibits a low limit of detection (8.6–37 ng L^?1), with wide linear ranges (0.10–25 μg L^?1) for each analyte and remarkable correlation coefficients (R²?=?0.9953–0.9995). The developed method was successfully used to detect estrogens in urine and serum samples. The six analytes were satisfactorily recovered between 76.2 and 107% with relative standard deviations ranging from 2.5 to 8.3% (n?=?3). The results demonstrated that the developed method, based on a poly(methacrylic acid/3-acrylamidophenylboronic acid-co-ethylene glycol dimethacrylate) monolithic column, is an effective enrichment approach toward the analysis of trace estrogens in human urine and serum samples.

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