乳状液法制备憎液溶胶Ⅰ.BaCO_3均匀粒子的制备

均匀胶体粒子的形成，除与反应条件（反应物浓度、陈化时间和温度、介质种类等）有关外，反应体系的环境也影响最终产物的形态，《至结晶结构．气溶胶法和微乳液法正是利用微环境中的‘水池效应”；分别制备出球形亚微米和纳米级的均匀粒子［‘－‘］、这些方法与水解法和相转化法等方法比较，反应物浓度要大几个数量级，而反应时间却短很多，因而受到研究人员的关注．乳状液也能提供亚微米、微米及以上级的微环境，因此，可以应用O／W乳状液乳液中的聚合反应制备亲液的分散体系．然而，极少有关利用w／O乳状液制备僧液溶胶的报导问；最近…     

Synthesis and structure of The Novel Layered Phase CsTi2Cl7

Reactions in the CsCl? TiCl₃? Ti system afford CsTiCl₃ (CsNiCl₃ type, a = 7.3086(7) Å, c = 6.0670(8) Å) and the new phase CsTi₂Cl₇, the structure of which was determined by single crystal X-ray diffraction means (P2/c, Z = 2, a = 7.0076(4) Å, b = 6.2256(4) Å, c = 12.000(2) Å, β = 92.175(6)°, R/R_w = 0.026/0.035 for 1403 reflections, 2Θ ≤ 60°, MoKα). The structure can be generated by condensation of TiCl₆ groups first through cis edges to form TiCl₂Cl_4/2 ribbons and then by interconnection of these with one chlorine per titanium to give layers, viz., [Ti(Cl)Cl_4/2Cl_1/2]^?. The remaining, singly bonded chlorine projects into the interlayer region and has a Ti? Cl distance 0.208 Å less than the average for the five, 2.466 Å, reflecting significant pi bonding of the chlorine to titanium. Possible interaction of the d orbitals on adjacent titanium(III) atoms is also considered.     

O(3P)原子与3-戊酮反应速率常数与温度关系的测定

由于燃烧机理和大气化学过程研究的需要,人们对有机化合物分子,如烷烃、烯烃及其衍生物与一些自由基,如O、OH和卤素原子的反应速率常数进行了广泛的测定。但酮类分子与这些自由基的研究则报道得很少,尽管人们早已发现酮类化合物是碳氢化合物被NO_x光氧化过程中产生的中间化合物。就我们所知,除有少量的关于O(~3P))原子与酮类分子反应速率常数测定的文献报道外,我们在前文中报道了用流动微波放电——化学发光方法测     

Determination of gentamycin by synchronous derivative fluorimetry

Use of synchronous first-derivative fluorimetry for determination of gentamycin is described. Gentamycin reacts with acetylacetone and formaldehyde in pH 5.6 HOAc/NaOAc buffer solution to form N-gentamyl-2,6-dimethyl-3,5-diacethyl-1,4-dihydropyridine[I] which is a fluorescent substance. Spectra of [I] and the reagent blank can be separated with synchronous derivative fluorimetry, and gentamycin can be determined directly. The synchronous spectral peaks of [I] and the reagent blank are at 434 and 411 nm, respectively. The first-derivative peak of [I] is at 425 nm. Effects of pH, foreign ions, buffer system, and heating time on the determination of gentamycin have been examined. The linear regression equation of the calibration graph is C=0.0513H-0.0416, with a correlation coefficient of linear regression of 0.9978. C means total potency of gentamycin: U ml(-1); H means peak height in the linear regression equation calibration graph. The linear range for the determination of gentamycin is from 0.00 to 3.00 U ml(-1). Recovery is from 95.06 to 112.0%, R.S.D. of 3.8%. The results determined by the fluorimetric method agreed roughly with those by the microbiological method. The method is simple and has low detection limit.     

ESR studies of γ-irradiated histone octamer and the histone H3

ESR spectrum of neat histone H3 γ-irradiated and observed at 77 K with low microwave power and modulation amplitude showed multiple resolved structure depicting nonequivalent interaction of the unpaired electron located at amido-carbonyl radical anion [– )NH–] of the peptide backbone with adjacent –NH– group and the β-proton of –CH group. The predominance of amido-carbonyl radical anion is in good accord with the expected partition of secondary electrons amongst the various electrophilic groups including peptide carbonyl and aromatic acid residues. Following a gradual rise of annealing temperature to room temperature, a double splitting spectrum from the well known -carbon amido radical was evolved.     

制备方法对Mg1.9Al0.1Ni合金储氢性能的影响

文中采用机械合金化(MA)和氢化燃烧法(HCS)制备了Mg1.9Al0.1Ni,通过对它们储氢性能的对比研究发现,MA优于HCS.采用MA制得的Mg1.9Al0.1Ni储氢合金具有较高的活性和高储氢量,对PCT结果进行计算,得出温度和氢平衡压的关系式.Mg1.9Al0.1Ni(MA)553K时100s内吸放氢量分别为2.67和2.54 mass%H.用XRD方法进行物相分析,表明添加适量Al没有改变Mg2Ni的物相结构,由于MA能够制备出纳米晶粒,使得Mg1.9Al0.1Ni合金具有更好的储放氢动力学性能.     

Redox Polymerization of Methyl Methacrylate in the Fluorous Triphasic System

Fluorous-phase chemistry is currently a topic of considerable interest1-6. Since fluoroustriphasic reactions were first described by the Curran and co-workers7, this triphasicsystem has been widely used for detagging7,8 and phase-vanishing reactions9-11. …     

The grain-boundary-related optical and electrical properties in polycrystalline p-type ZnO films

Cathodoluminescence spectra and electrical properties of the N doped and N–Al codoped p-type ZnO films and the dependence of these two properties on the post-annealing were investigated. Spectral analyses show that the intensity of the green emission strongly depends on the annealing ambient and closely relates with the width of the electron depletion region at the particle boundary. The conducting type and electrical properties of N doped and N–Al codoped ZnO films are greatly affected by the annealing process. The grain boundary effect was proposed to explain the green emission behavior and the p-type conduction in polycrystalline ZnO based films.     

A recyclable fluorous organocatalyst for Diels-Alder reactions

Chiral fluorous imidazolidinone catalyst 2 provides consistently high enantioselectivities in Diels–Alder reactions of dienes and ,β-unsaturated aldehydes. The catalyst can be readily separated from the reaction products by fluorous solid-phase extraction, and recovered in excellent purity for direct reuse.     

LC Determination of Curcumin in Dog Plasma for a Pharmacokinetic Study

A rapid, simple, and sensitive high-performance liquid chromatographic method for quantification of curcumin in dog plasma has been developed and validated. After addition of the internal standard (berberine), plasma was acidified and extracted with ethyl acetate. Analysis was performed on a C₁₈ column. The mobile phase was acetonitrile–5% acetic acid, 52:48 (v/v) and the flow rate 1.0 mL min^?1. The eluent was monitored at 425 nm. Chromatographic separation was achieved in less than 7 min and the calibration plot was linear over the concentration range 2–128 ng mL^?1. Intra- and inter-assay variability were less than 7.3%. The accuracy ranged from 98.7 to 105.0%. The method was successfully applied to a pharmacokinetic study of curcumin in dogs.