d‐Secoestrone derivatives. VI. 17β‐Benzyl‐17α‐hydroxy‐3‐methoxyestra‐1,3,5(10)‐trien‐16‐one

The title mol­ecule, C₂₆H₃₀O₃, shows a novel chemical rearrangement of the substituents at position 17, i.e. an α‐­orientation of the hydroxy group and a β‐orientation of the bulky benzyl moiety. The packing arrangement consists of coils formed by O2?O3 hydrogen bonds along the c axis. The compound shows complete loss of oestrogenic activity, and neither does it exhibit an antagonistic effect.     

TLC Separation and Identification of Heavy Metals Present in Cotton Material

JPC – Journal of Planar Chromatography – Modern TLC - Optimization of the separation and identification of heavy metals present in cotton material has been performed by...     

HAsS2异构体结构与稳定性

在MP2/6-311++G(d,p)和QCISD(t)/6-311++G(3df,2p)(单点)水平下计算得到9个异构体和10个过渡态的HAsS₂体系势能面.异构体cis-HSAsS(E1)的能量最低,其次是trans-HSAsS(E2)、具有AsSS三元环的立体HAs(S)S(C_{s,E3)和HAs(S)S(C2v,E4)结构的异构体,能量分别比cis-HSAsS高1.46,60.78和93.63kJ/mol.根据体系的势能面,异构体E1,E2,E3和E4具有一定的动力学稳定性.AsH和S2第一步反应产物将会异构化为具有较高动力学稳定性的异构体E3,而SH和AsS第一步反应产物将会异构化为E1.计算结果与HNO2,HNS2,HPO2,HPS2和HAsO2等价电子相同的分子的势能面进行了比较.}     

镍基气凝胶催化CH4-CO2重整制取合成气反应的研究 Ⅲ.影响催化剂积碳性能因素的探讨

考察了823K焙烧的干凝胶xNCA550、气凝胶aNCA550及浸渍型催化剂iNCA550在923K、1073K、1173K反应温度下的积碳行为，对催化剂表面碳的活性及类型进行了分析，并探讨了影响催化剂积碳的因素。实验结果表明，随反应温度的提高，催化剂的积碳能力减弱，尤以气凝胶催化剂aNCA550明显。催化剂的积碳主要发生在反应的初期，反应温度越高，到达积碳量相对稳定期所需要的时间越短；随着反应时间的延续，催化剂积碳量缓慢增长，并且表面碳的活性降低。催化剂的酸性和镍晶粒大小是影响其积碳性能的主要内在因素，而它们对积碳的影响程度受反应温度的影响，反应温度越高，催化剂表达酸性中心利于积碳的作用越小，小晶粒镍抑制催化剂积碳的能力越强。     

磁化作用对汽油动态挥发性影响的研究

用热重（TG）分析和自行设计的原位动态挥发实验，研究了在不同条件下汽油的挥发性，结果表明，磁化空气或磁化汽油都可提高汽油的挥发性，而汽油和空气共同磁化，可更大幅度地提高汽油的挥发性。     

Sol-Gel Processing of PbZrO3 Thin Films

PbZrO₃ (PZ) thin films have been prepared by 2-methoxyethanol route from lead oxide or lead acetate and zirconium n-butoxide. The use of lead oxide as lead source and the seeding layer of TiO₂ on Pt/TiO₂/SiO₂/Si substrate facilitate the formation of the perovskite phase.     

Development and optimization of the SPE procedure for determination of pharmaceuticals in water samples by HPLC‐diode array detection

This paper focuses on the investigation of different types of SPE sorbents for the preconcentration of eight veterinary pharmaceuticals from water samples. The pharmaceuticals studied were sulfamethazine, sulfadiazine, sulfaguanidine, trimethoprim, oxytetracycline, enrofloxacin, norfloxacin and penicillin G/procaine. Five different SPE materials (Strata‐X, Strata‐X‐C, Strata SDB‐L, Strata C8 and Strata C18) from Phenomenex were compared with Oasis HLB with a view to obtaining the best cartridges for all pharmaceuticals investigated. Extraction efficiency was determined by HPLC with diode array detection (DAD). HPLC‐DAD separation and quantification of the selected pharmaceuticals were carried out under gradient elution by a binary mixture of 0.01 M oxalic acid and ACN based on cyano modified column (LiChrosphere 100 CN) from Merck. Strata‐X provided the best results in the preconcentration of 100 mL water samples, yielding average pharmaceutical recoveries of higher than 90%, except for sulfaguanidine (76.1%). The developed Strata‐X‐HLPC‐DAD method was validated and applied, for the efficient investigation of reverse osmosis/nanofiltration membranes and for the removal of these eight pharmaceuticals from the production wastewater samples. NF90 and XLE membranes were shown to be the best for the rejection of all investigated pharmaceuticals.     

A novel soluble polyamide containing xanthene structure and trifluoromethylphenoxy pendent

<正>A novel polyamide containing xanthene structure and trifluoromethylphenoxy pendent was prepared from 9,9-bis[4-(4- aminophenoxy)phenyl]xanthene,a novel diamine with 2-(4-trifluoromethylphenoxy)terephthaloyl chloride,by the low temperature polycondensation.This new polyamide with the inherent viscosity of 0.95 dL/g was amorphous and readily soluble in polar solvents such as DMAc,m-cresol,etc.This polyamide showed the glass transition temperature(T_g) of 236℃,decomposition temperature (Td) at 5%weight loss of 455℃and char yield of 56%at 800℃in N_2.Transparent,flexible,and tough film of the polymer cast from DMAc solution exhibited tensile strength of 93 MPa,elongation at break of 14%,initial moduli of 2.2 GPa.The electric properties such as the dielectric constant of 3.03(1 MHz) and surface resistance(2.78×10~(14)Ω),and the moisture uptake of 1.36% were also described.     

Erratum to: Solution behavior of aqueous mixtures of low and high molecular weight hydrophobic amphiphiles

Mixtures of a hydrophobic triblock copolymer (L121, PEO₅PPO₆₈PEO₅) and a hydrophobic anionic surfactant (AOT, Sodium bis(2-ethylhexyl)sulfosuccinate), each alone forming turbid vesicular solutions in water, aggregate to produce a thermodynamically stable, transparent and isotropic solution. Mixed AOT/L121 aggregates could be confirmed by fluorescence, surface tension, differential scanning calorimetry (DSC) and isothermal titration calorimetry (ITC). In an isotropic region, where mixed aggregates are formed, there is a synergistic interaction between monomers of AOT and L121 in the mixture. In addition, Small Angle Neutron Scattering (SANS) experiments provided evidence that mixed aggregates have the shape of either spheres (with a certain polydispersity) or very short ellipsoids (axial ratio below 2), confirming a transition from giant multilamellar vesicles to small aggregates upon mixing the two hydrophobic amphiphiles. Upon dilution, the morphology changes to disk-like. From an examination of the results of all the methods the peculiar behavior of the mixed AOT/L121 system is explained.     

Carbon-bromine cleavage by dimethyl sulfoxide: the key step of C(5) functionalization of push-pull 2-alkylidene-4-oxothiazolidine vinyl bromides

Push-pull 2-alkylidene-4-oxothiazolidine vinyl bromides undergo efficient C(5) functionalization through DMSO-assisted carbon-bromine cleavage, followed by a bromine transfer-substitution (or elimination) sequence. A mechanism for this novel transformation is proposed.