ALMOST AUTOMORPHIC MILD SOLUTIONS TO SOME FRACTIONAL DELAY DIFFERENTIAL EQUATIONS

In this paper,a new and general existence and uniqueness theorem of almost automorphic mild solutions is obtained for some fractional delay differential equations,using sectorial operators and the Banach contraction principle.     

Chemical synaptic coupling-induced delay-dependent synchronization transitions in scale-free neuronal networks

Chemical synaptic couplings are more common than electric(gap junction) connections in neurons.In this paper,the firing synchronizations induced by chemical synaptic coupling in chemically delayed scale-free networks of modified Hodgkin-Huxley neurons have been studied.It was found that the chemical coupling-induced synchronization transitions are delay-dependent and much different for various delay lengths.In the absence of delay,the neurons exhibit a transition from chaotic bursting(CB) to bursting synchr...     

A new isobenzofuranone derivative from a marine Streptomyces sp.

One new isobenzofuranone derivative,1,4-dimethoxy-3-(3R*-hydroxy-3R*-methyl-1-tetralone)-1(3H)-isobenzofuran(1),was isolated from the broth of marine Streptomyces sp.M268.The structure was elucidated by spectroscopy characteristics as well as comparison with the literature.Compound 1 exhibited cytotoxicities against human cancer cell,HL-60,A549,and BEL-7402.     

甲磺酸培氟沙星-La(Ⅲ)络合物的荧光特性研究及应用

在pH 5 6的乙酸 乙酸钠缓冲溶液中 ,La3 与甲磺酸培氟沙星形成络合物。该络合物的荧光强度是甲磺酸培氟沙星的 1 5倍 ,最佳激发波长与最佳发射波长分别为 2 76和 4 4 0nm ,线性范围为 0 0 4～ 2 0mg·L-1,测定下限为 2 8μg·L-1。该体系的抗干扰能力与稳定性较好 ,成功地用于直接测定人血清中甲磺酸培氟沙星含量 ,测定结果为 :含量 4 79mg·L-1,RSD 6 3% ,回收率 95 %。本法亦用于测定胶囊中甲磺酸培氟沙星含量 ,测定结果与紫外 可见光度法一致     

Synthesis and characterization of magnetic and luminescent Fe_3O_4/CdTe nanocomposites using aspartic acid as linker

In this study,the preparation of a new kind of magnetic and luminescent Fe₃O₄/CdTe nanocomposites was demonstrated. Superparamagnetic Fe₃O₄ nanoparticles were first synthesized by hydrothermal coprecipitation of ferric and ferrous ions,followed by the modification of their surfaces with tetramethylammonium hydroxide（TMAOH） and the chemical activation with aspartic acid.The surface-modified Fe₃O₄ nanoparticles were then covalently coated with CdTe quantum dots（QDs）,which were modified with mercaptoacetic acid（MPA）,to form the Fe₃O₄/CdTe magnetic and luminescent nanocomposites through the coordination of the amino groups on the surfaces of Fe₃O₄ and the carboxyl groups on CdTe QDs.The structure and properties of as-synthesized nanocomposites were characterized.It was indicated that the nanocomposites possessed structure with an average diameter of 40- 50 nm,yellow-green emission feature and room temperature ferro-magnetism.Both the fluorescence and UV-vis absorption spectra of the nanocomposites showed a blue shift comparing with those of CdTe QDs.The mechanism of the blue shift was presented.The nanocomposites retained the ferromagnetic property with a saturation magnetization of 8.9 emu/g.     

A NOTE ON THE INTERACTIONS OF ELEMENTARY WAVES FOR THE AR TRAFFIC FLOW MODEL WITHOUT VACUUM

In this note, we consider the interactions of elementary waves for the traffic flow model proposed by Aw and Rascle when the vacuum is not involved. The solutions are obtained constructively and globally when the initial data consist of three pieces of constant states. Furthermore, it can be found that the Riemann solutions are stable with respect to such small perturbations of the initial data in this particular situation by investigating the limits of the solutions as the perturbed parameter ε goes to zero.     

铜印迹螯合树脂对金属离子的吸附特性

研究了铜印迹螯合树脂与非印迹螯合树脂对金属离子的吸附性能，结果表明：铜印迹树脂对Cu^2 、Ni^2 、Zn^2 的吸附量比非印迹树脂有显著增大,两者对Cu^2 的吸附速率均较快，其表观吸附速率分别为0．044s^-1和0．040s^-1；印迹树脂对Cu^2 的吸附可用Langmuir或Freundlish等温式来描述；其动态吸附曲线与离子的起始浓度相关；用0．5mol／L HCl即可快速洗脱吸附的Cu^2 ，树脂具有较强的再生能力，可以重复使用。     

Electronic structure and optical properties of Sn_(2x)Ga_(2(1-x))O_3 compounds

Band structure, density of states, electron density difference, and optical properties of intrinsic β-Ga2O3 and Sn2xGa2(1-x)O3 (x= 3.125%-6.25%) compounds are studied using first-principle calculations based on the density functional theory. The anisotropic optical properties are investigated by means of the complex dielectric function, which are explained by the selection rule of band-to-band transitions. All the calculation results indicate that the conductivity of Sn2xGa2(1-x)O3 is super to β-Ga2O3, and ...     

ICP-AES法对茶叶捕集水溶液中镉(Ⅱ)、铅(Ⅱ)行为的研究

用ICPAES法研究了绿茶和红茶对水溶液中镉(Ⅱ)、铅(Ⅱ)的捕集行为,考察了时间、pH、温度等因素的影响。结果表明,绿茶对水中镉(Ⅱ)、铅(Ⅱ)的捕集30min基本达到平衡,而红茶的捕集平衡时间约为60min。当pH<4时捕集率随pH值减小而显著降低,当pH>4时捕集率变化趋缓;当pH<6时茶样对铅(Ⅱ)的捕集率大于镉(Ⅱ),而当pH>6之后则正相反,这与不同酸度的溶液中茶叶的带电状态及镉(Ⅱ)、铅(Ⅱ)的形态分布有关。升高温度有利于绿茶对镉(Ⅱ)、铅(Ⅱ)的捕集,而红茶变化不大;捕集后的镉(Ⅱ)、铅(Ⅱ)在25℃下用水洗脱困难,其中绿茶与铅(Ⅱ)的相互作用较强。     

广义复数上的函数

本文用复变函数方法统一讨论既含椭圆型也含双曲型的一类线性偏微分方程。可以看到它们的许多个性寓于其共性之中。