多支链烷基苯磺酸钠水溶液的表面性质

用自制的四种高纯度多支链烷基苯磺酸钠,研究了支链结构对其表面性质的影响.结果表明,随支链烷基碳数增加,临界胶束浓度降低,标准吸附自由能DGadӨ更负;但是,饱和吸附量Γmax却随支链烷基碳数增加而减小,且临界胶束浓度时的表面张力γcmc随吸附量减小而降低,表现出与一般表面活性剂不同的变化趋势.从多支链烷基苯磺酸钠的分子结构特点,解释了随支链烷基碳数增加Γmax和γcmc的变化规律,探讨了分子的独占面积(as)对Γmax及γcmc的影响.     

Temperature-sensitive polypeptide brushes-coated mesoporous silica nanoparticles for dual-responsive drug release

A multifunctional nanohybrid based on mesoporous silica nanoparticle and biocompatible polypeptide was fabricated for targeted and dual-responsive therapy of tumor cells.     

亚单层InGaAs量子点-量子阱异质结构的时间分辨光致发光谱

测定了亚单层InGaAs/GaAs量子点-量子阱异质结构在5K下的时间分辨光致发光谱.亚单层量 子点的辐射寿命在500 ps 至 800 ps之间，随量子点尺寸的增大而增大，与量子点中激子的 较小的横向限制能以及激子从小量子点向大量子点的隧穿转移有关.光致发光上升时间强烈 依赖于激发强度密度.在弱激发强度密度下，上升时间为 35 ps，纵光学声子发射为主要的 载流子俘获机理.在强激发强度密度下，上升时间随激发强度密度的增加而减小，俄歇过程 为主要的载流子俘获机理.该结果对理解亚单层量子点器件的工作特性非常有用. 关键词： 亚单层 量子点-量子阱 时间分辨光致发光谱     

发射光谱研究大气压等离子体射流的气体温度

采用介质阻挡放电等离子体喷枪装置,在大气压下流动氩气中产生了射流等离子体。利用光电倍增管,对射流等离子体进行了时空分辨测量,分析了等离子体喷枪内介质阻挡放电和外部等离子体羽的放电特性。利用高分辨率光谱仪采集等离子体羽处的发射光谱,通过对发射光谱中OH(A2Σ+→X2Π,307.7～308.9nm)及N2+的第一负系(B2Σ+u→X2Π+g,390～391.6nm)谱线拟合得到了射流等离子体的转动温度,拟合得到的转动温度分别为443和450K。在5%的误差范围内,这2种方法得到的结果是一致的。由于在大气压下,转动温度近似等于产生气体放电的气体温度,所以可以确定大气压射流等离子体气体温度。利用该方法研究了不同电压下的气体温度,发现气体温度随着外加电压增加而增大。     

Structure equation and Mei conserved quantity for Mei symmetry of Appell equation

This paper investigates structure equation and Mei conserved quantity of Mei symmetry of Appell equations for non-Chetaev nonholonomic systems. Appell equations and differential equations of motion for non-Chetaev nonholonomic mechanical systems are established. A new expression of the total derivative of the function with respect to time $t$ along the trajectory of a curve of the system is obtained, the definition and the criterion of Mei symmetry of Appell equations under the infinitesimal transformations of groups are also given. The expressions of the structure equation and the Mei conserved quantity of Mei symmetry in the Appell function are obtained. An example is given to illustrate the application of the results.     

LD泵浦Cr∶YAG被动调Q 556nm黄光激光器

通过对谐振腔镜镀制合理的激光薄膜，成功实现了LD泵浦Nd∶YAG 1.111 μm激光谱线的运转.利用LBO腔内倍频Nd∶YAG/Cr∶YAG结构获得了高重复频率被动调Q556 nm全固态黄光激光器，在注入泵浦功率为1.6 W时，得到平均功率51 mW，脉冲宽度48 ns,重复频率8.9 kHz,峰值功率高达119 W的脉冲黄光输出.     

Simultaneous analysis of multiple bioactive constituents in Rheum tanguticum Maxim. ex Balf. by high-performance liquid chromatography coupled to tandem mass spectrometry

A simple, rapid method was developed using on-line high-performance liquid chromatography (HPLC)-diode array detection (DAD)/electrospray ionization mass spectrometry (ESI-MS) to simultaneously analyze multiple bioactive constituents in the extract of Rheum tanguticum Maxim. ex Balf. (Dahuang), a traditional Chinese medicine (TCM). Many bioactive constituents gave prominent [M-H]- ions in the negative ion ESI mass spectra. Among them, 41 different constituents including 16 anthraquinone derivatives, 7 phenylbutanone glucopyranosides, 4 stilbenes and 14 tannins were unambiguously identified or tentatively characterized based on their retention times, UV spectra and mass spectra in comparison with the data from standards or references. Meanwhile, some principles of fragmentation behavior for different types of constituents were proposed, which could contribute to the elucidation of these constituents in Rheum tanguticum.     

Facile synthesis of mesoporous WO3@graphene aerogel nanocomposites for low-temperature acetone sensing

Nanocomposites constructed by combining mesoporous metal oxides and graphene have received tremendous attention in wide fields of catalysis,energy storage and conversion,gas sensing and so on.Herein,we present a facile interface-induced co-assembly process to synthesize the mesoporous W03@graphene aerogel nanocomposites(denoted as mW03@GA),in which graphene aerogel(GA) was used as a macroporous substrate,mesoporous W03 was uniformly coated on both sides of graphene sheets through a solvent evaporation-induced self-assembly(EISA) strategy using diblock copolymer poly(ethylene oxide)-b-polystyrene(PEO-b-PS) as a template.The resultant mW03@GA nanocomposites possess well-interconnected macroporous graphene networks covered by mesoporous W03 layer with a uniform pore size of 19 nm,high surface area of 167 m~2/g and large pore volume of 0.26 cm~3/g.The gas sensing performance of mW03@GA nanocomposites toward acetone and other gases was studied,showing a high selectivity and great response to acetone at low temperature of 150℃,which could be developed as a promising candidate as novel sensors for VOCs detection.     

锰-二茂铁基配位聚合物微球的制备与表征

采用溶剂热法制得了一系列锰-二茂铁基配位聚合物微球,系统研究了反应时间、反应物浓度等因素对配位聚合物微球的形貌和尺寸的影响规律,采用SEM、TEM、PXRD、EDX和FTIR等方法研究了微球的形貌、尺寸和结构等.发现通过调节反应时间,可使微球的尺寸约在4 ～9 μm范围内变化,提高反应物浓度可使微球从光滑的球形结构向核...