19F+27Al耗散反应中双核系统的转动与形变

测量了¹⁹F+²⁷Al耗散反应产物B,C,N,O,F和Ne的激发函数,入射束流的能量从110.25MeV到118.75MeV, 能量步长为250keV. 从产物的 能量自关联函数中提取了反应中所形成的中间双核系统的转动惯量, 与相粘模型计算的刚体转动惯量相比较, 结果表明形成的双核系统有大的形变.     

On congruence lattices of regular semigroups with Q-inverse transversals

Communicated by F. Pastijn     

小长径比垂直管气液两相流动特性分析

实验观察了小长径比垂直上流管内流型及特点,并对管入口处的压力波动特性和系统的压差波动特性进行了试验研究.结果表明:小长径比(L/D)垂直管内流型表现为泡状流、塞状流、乳沫状流、环状流和液束环状流;分别增加管线中的气量、液量,或者同时增加气液流量,均会造成垂直管入口处压力波动的均值和最大压力的增加;压力信号的概率密度(PDF)大部分呈双峰分布,也存在单峰和多峰分布;差压信号的概率密度符合正态分布,其功率谱密度同压力信号相比具有频率波动范围宽、幅值小的特点.     

YZr2OZr3:Er3+纳米晶anti-Stokes发光性质的研究

采用均相沉积法制备了不同Er³⁺离子浓度掺杂的Y₂O₃纳米晶, 应用XRD，SEM和PL光谱对该体系材料进行了表征.在Y₂O₃:Er³⁺纳米材料体系中, 观察和研究了Stokes及anti-Stokes PL谱强度与Er³⁺离子摩尔浓度变化的关系, 当Er³⁺离子浓度为2.0mol%时, anti-Stokes PL强度最强.粉末X 关键词： 氧化钇纳米晶 anti-Stokes PL 双光子吸收     

Synthesis,crystal structure and property of a novel azide-bridged one-dimensional chain copper(II) complex with a dinucleating macrocyclic polyamine

An azide-bridged polymeric cationic chain complex, [LCu₂(N₃)₂]n(ClO₄)_2n ·n(H₂O)**, where L=the dinucleating macrocyclic ligand bis-p-xylylBISDIEN, has been prepared and characterized by x-ray crystallography, u.v.-vis and i.r. spectra, and by magnetic measurements. The structure consists of cationic azide-bridged [LCu₂(N₃)₂]²⁺ (unit) chains, non-coordinated perchlorate anions and crystallized water molecules. The azide anion is bound to two copper atoms in neighboring units with an end-to-end bridging mode. In each unit, the copper atoms have a different coordination geometry; Cu(1) is a four-coordinated, distorted square-planar geometry, whereas Cu(2) is a five-coordinated, distorted square-pyramid. The electronic spectra of the title complex differ in anhydrous and in aqueous MeCN solutions, indicating that dissociation and solvation occur in aqueous solutions. The characteristic i.r. absorptions of azides and perchlorates are described. Magnetic moments vary from 2.05 (B.M.) at 300K to2.01 (B.M.) at 80K, which suggests that very weak interactions exist between the metals.     

抗癌涪性β-榄香烯衍生物的合成

β-榄香烯是从温莪术中提取的一种抗癌有效成份。它是只含 C、H 两种元素的倍半萜烯。但是,它不溶于水,不易被肌体吸收,对肌体刺激作用大,因而在临床上受到很多限制。为克服这些缺点,有必要对其进行分子修饰,接上一些极性基团。以前的工作表明,β-榄香     

改性磁性壳聚糖微球对Cu2+、Cd2+和Ni2+的吸附性能

Fe3O4/ chitosan magnetic microspheres of 50 to 80 滋m were prepared using the inverse phase emulsion dispersion and chemical crosslinking technology, and then modified with ethylenediamine for use in the adsorption of heavy metal ions. The adsorption properties of the modified Fe3O4/chitosan toward Cu2+, Cd2+ and Ni2+ were investigated. It was found that the adsorption capacities of Cu2+ and Ni2+ increased with pH, and a maximum adsorption for Cd2+ occurred at pH=3. The saturated adsorption capacities calculated by Langmuir isotherms were 54.3 mg·g-1 for Cu2+, 20.4 mg·g-1 for Cd2+, and 12.4 mg·g-1 for Ni2+, respectively. The adsorption kinetics were well described by pseudo-second-order equation models. The experimental results showed that the Fe3O4/chitosan modified with ethylenediamine presented higher adsorption selectivity for Cu2+ than for Cd2+ and Ni2+ in all studied pH ranges.     

以廉价国产化试剂合成大孔径高度有序介孔氧化硅分子筛

新一代大孔径（１～３０nm）介孔分子筛在大分子转化、吸附、生物大分子分离以及电磁、传感器、光电子等领域均具有广泛的应用前景犤１～４犦。由昂贵的长链有机季铵盐阳离子表面活性剂为模板合成的MCM－４１介孔分子筛，由于其孔径小，水热稳定性差，受到了较大的限制。与其相比，以嵌段高分子共聚物为模板剂合成的介孔分子筛SBA－１５具有孔径均一，有序度高，并且其孔径大以及水热性能良好等优点，近年来得到了广泛的研究犤５～９犦。其骨架上修饰有机硅烷，可用于重金属的分离、回收，以及蛋白质的控释与分离。利用主－客体方法在SB…     

Debye type dielectric relaxation and the glass transition of alcohols

Many hydrogen-bonded liquids, especially glass-forming cases, display a dielectric relaxation behavior that differs qualitatively from that of other simple liquids. The majority of models aimed at explaining this unusual dielectric behavior associate the prominent Debye process with structural relaxation, viscous flow, and the glass transition. We perform dielectric and calorimetric studies of glass-forming mixtures of 2-ethylhexylamine and 2-ethyl-1-hexanol across the entire composition range. The kinetic glass transition temperature derived from the large dielectric Debye peak decreases, whereas that of the much smaller and asymmetrically broadened peak increases upon addition of amine. Only the latter feature coincides with the calorimetric glass transition results, implying that molecular structure and dielectric polarization fluctuate on time scales that can differ by orders of magnitude in many hydrogen-bonding liquids.     

Highly Efficient One-Pot Synthesis of 2-Arylmethyl N-Substituted Anilines via Yb（OTf）3 Catalyzed Three-Component Reaction

An efficient method has been developed for one-pot three-component coupling reactions of various aldehydes, 1-cyclohexen-2-one, and primary or secondary amines in the presence of a catalytic amount of Yb（OTf）3 under mild conditions to afford the corresponding 2-arylmethyl N-substituted anilines in good yields. In addition, the catalyst was easily recovered and could be reused for at least four cycles without any loss of activity.