One-pot sequential synthesis of magnetically separable Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/AgCl photocatalysts with enhanced activity and stability

Magnetically separable Fe₃O₄/AgCl photocatalysts were prepared by a one-pot sequential method. A series of techniques proved the hybrid structure of Fe₃O₄/AgCl composites. Fe₃O₄/AgCl composites had a much higher photocatalytic activity toward Rhodamine B (RhB) degradation than pure AgCl under the simulated solar light irradiation. The existence of metal Ag resulted in high photocatalytic activity of Fe₃O₄/AgCl, which was related with the amount of metallic Ag. The scavenging experiments showed that the degradation reaction most probably was initiated by the photoinduced single-electron transfer, and the generation of superoxide anion (O ₂ ^-· ) played a significant role. The composite photocatalysts could be recycled by applying an external magnetic field, and the reused composites maintained their original photocatalytic activity. Fe₃O₄/AgCl composites were highly efficient, magnetically separable, and recoverable. This proves their potential applications in the photodegradation of organic pollutants.     

PtFe掺杂石墨烯抗CO中毒性能的理论研究

基于密度泛函理论第一性原理研究了以单空位缺陷(SV)石墨烯为载体的Pt,Fe及PtFe二元金属催化剂的抗CO中毒能力.结果表明,对于单金属原子Pt和Fe,Fe更易吸附在SV石墨烯上;而对于PtFe二元金属催化剂,SV石墨烯对其固定能力明显好于Pt-SV,即Pt催化剂中掺杂Fe大大增加了SV石墨烯对金属催化剂的稳定性.Pt,Fe及PtFe二元金属催化剂抗CO中毒能力的研究结果表明,PtFe-6结构的抗CO中毒能力明显强于Pt-SV,接近于Fe-SV的抗CO中毒能力,在所有二元金属催化剂中PtFe-6的稳定性最好,明显优于Pt在SV石墨烯上的稳定性.通过在Pt中加入非贵金属Fe既可提高DMFC中阳极Pt催化剂的抗CO中毒能力,又可提高其催化活性.     

几个TTF衍生物的电荷转移情况研究

本文报道了用循环伏安法研究了几个 TTF 衍生物的电荷转移情况,发现都是两个单电子转移的可逆氧化还原波,其半波电位受溶剂的极性和电子效应影响较大,在 CH_2Cl_2溶液中,其 E_(1/2)大小顺序为:TMT-TTF相似文献   

Lasiodiplodins from mangrove endophytic fungus Lasiodiplodia sp. 318#

Four new lasiodiplodins (1–4), together with three known analogues, have been isolated from a mangrove endophytic fungus, Lasiodiplodia sp. 318#. Their structures were elucidated by spectroscopic techniques. Cytotoxic activities of compounds 1–7 were evaluated in vitro against human cancer lines THP1, MDA-MB-435, A549, HepG2 and HCT-116. Compound 4 exhibited moderate cytotoxic activities.     

Isolation, structure elucidation, and mutagenicity of four alternariol derivatives produced by the mangrove endophytic fungus No. 2240

A new alternariol derivative, 2240B (1), together with alternariol (2), alternariol 4,10-dimethyl ether (3), and alternariol 4-methyl ether (4), was isolated from the ethyl acetate extract of the liquid medium GYT of No. 2240, the mangrove endophytic fungus from the South China Sea Coast. The structure of compound 1 was unambiguously elucidated as alternariol 4-methyl-10-acethyl ester by spectra including one/two-dimensional NMR, HREIMS, IR, and UV. The structures of compounds 2–4 were also established by spectroscopic analyses and comparison with related literature data. The anticancer tests showed that compounds 2 and 4 had strong activities against KB and KBv200 cells with IC₅₀ values of 3.17, 3.12, and 4.82, 4.94 μg/mL, while compounds 1 and 3 exhibited weak activities against the two kinds of tumor lines with IC₅₀ values of more than 50 μg/mL. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 235–238, May–June, 2008.     

Transesterification of dimethyl carbonate with phenol over a bimetallic molybdenum and copper catalyst

Mo-Cu bimetallic oxides were found to be efficient heterogeneous catalysts for the transesterification of dimethyl carbonate (DMC) with phenol. When the reaction was carried out between 150 and 180°C, with a molar of Mo/Cu of 1:1, molar ratio of phenol/DMC of 1:1, 4.8 wt.% of the catalyst, 9 h, the conversion of phenol was 49.9%, and the total yield of MPC and DPC was 45.4%. Catalyst reuse showed a gradual decline in the catalytic activity. The decrease in catalytic activity might be due to leaching out of Mo and Cu, and/or carbon deposition.     

染料分子荧光淬灭规律研究

本文研究了若丹明B、若丹明6G和吖啶橙三种染料分子吸附于银表面上时的荧光变化规律,发现在银胶颗粒表面的吸附均造成了其荧光强度急剧而大幅度的淬灭,淬灭随时间呈双曲线型衰减。同时利用这一实验结果对分子在表面间的吸附系数与脱附系数——这些表征分子与表面相互作用的重要参数——表达式进行了初步推导。     

ALMOST SURE CONVERGENCE OF THE STABLE TAIL EMPIRICAL DEPENDENCE FUNCTION IN MULTIVARIATE EXTREME STATISTICS

ThisresearchissupportedbytheNationalNaturalScienceFoundationofChina.1.IntroductionandTheoremsSupposethatF(x,y)isabivariatedistributionfunctionwithtwocontinuousmarginaldistributionfunctions,say,FIandF2.DefineFissaidtohaveastabletaildependencefunction(STDF)l(x,y)ifforx20andy20,whereF(x,y)~1--F(QI(x),QZ(y)).TheconceptofSTDFwasintroducedin[6].Supposethat{(Xi,K),i21}isasequenceofi.i.d.randomvectorswithdistributionF(x,y).Ifthereedestsomesequencesofconstantsan>0,on>0,b.ERandd.ER,n>1.suc…     

染料分子SERS与FTIR－Raman的比较研究

本文研究了强荧光染料罗丹明Ｂ（ＲｈＢ）的表面增强拉曼（ＳＥＲＳ）和傅里叶变换红外拉曼（ＦＴＩＲ－Ｒａｍａｎ）光谱，比较了这两种技术在研究荧光物质拉曼效应方面各自的特点和优势，并对两种方法获得的振动模式的差异及ＲｈＢ在银表面的吸附方式进行了讨论。