Preparation of diphenylcarbazide-directed CdSe quantum dots and selective determination for Cr(VI)

CdSe quantum dots (QDs) were synthesized using diphenylcarbazide (DL) to sequester QDs precursors (Cd²⁺) in situ. Fluorescence (FL) analysis showed the successive synthesis of QDs could be realized by capping with DL and the binding between DL and Cd²⁺. The average QDs particle size was about 5-20 nm by high-resolution transmission electron microscopy (HRTEM). Fourier transform infrared (FT-IR) spectra showed that CdSe QDs could be chemically bonded with DL. The formation of QDs-DL-Cr(VI) could lower the fluorescence intensity of QDs. In a certain concentration range, the fluorescence intensity and Cr(VI) concentration presented a linear relationship. As a result, this phenomenon could be used to determine the Cr(VI) concentration in the range of 0-24 ×10^?6 mol· L^?1.     

Composite semiconductor quantum dots CdSe/CdS Co-sensitized TiO2 nanorod array solar cells

CdSe/CdS semiconductor quantum dots co-sensitized TiO2 nanorod array was fabricated on the transparent conductive fluorine-doped tin oxide (FTO) substrate using the hydrothermal and successive ionic layer adsorption and reaction (SILAR) process. The structural and morphological properties of the samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The results indicate that CdSe/CdS QDs are uniformly coated on the surface of the TiO2 nanorods. The shift of light absorption edge was monitored by taking UV-visible absorption spectra. Compared with the absorption spectra of the TiO2 nanorod array, deposition of CdSe/CdS QDs shifts the absorption edge to the higher wavelength. The enhanced light absorption in the visible-light region of CdSe/CdS/TiO2 nanorod array indicates that CdSe/CdS layers can act as co-sensitizers in quantum dots sensitized solar cells (QDSSCs). By optimizing the CdSe layer deposition cycles, a photocurrent of 5.78 mA/cm2, an open circuit photovoltage of 0.469 V and a conversion efficiency of 1.34 % were obtained under an illumination of 100 mw/cm2.     

系统素量子点生物荧光探针的构建及特性

采用碳二亚胺法偶联系统素多克隆抗体和水溶性CdSe/ZnS量子点,制备了系统素量子点免疫荧光探针( antiSys-CdSe/ZnS),并对该探针的特异性和荧光特性进行了研究.结果表明,antiSys-CdSe/ZnS和系统素多克隆抗体的中点效价分别为1∶3.21×104和1∶9.45×104,两者对系统素的免疫识别能力近似;体系中硼酸缓冲液的pH为9.0时,antiSys-CdSe/ZnS量子点荧光探针溶液的荧光强度最强,其荧光强度约为原量子点荧光强度的47％;在牛血清白蛋白(BSA)存在时,antiSys-CdSe/ZnS 的荧光强度明显增加;当体系中含有1％ BSA时,antiSys-CdSe/ZnS溶液的稳定性和荧光强度最佳.     

Mn^2＋和Ce^3＋共掺杂的CdS量子点制备及其光谱研究

采用低温水热技术,以硫脲为稳定剂,在90℃的水相中合成了发蓝色荧光的Mn^2＋和Ce^3＋共掺杂的CdS体量子点。用透射电子显微镜对该量子点形貌进行了表征,其直径约为10 nm的球形颗粒。研究了该量子点的紫外-可见吸收光谱、荧光发射光谱以及荧光光谱随时间的变化。结果表明,Mn^2＋和Ce^3＋共掺杂使CdS量子点的发光强度提高10倍;该量子点具有较好的发光稳定性。     

油酸钠为稳定剂合成CdS（CdSe）纳米粒子及表征

针对CdS（CdSe）等半导体纳米粒子制备过程中使用的有机溶剂难回收、成本高、难以实现工业化等问题,以油酸钠为稳定剂,乙醇为溶剂,乙酸镉和硫脲（或硒氢化钠）为前驱物,制备了CdS和CdSe纳米粒子.采用紫外-可见吸收光谱、荧光光谱、广角x射线衍射和透射电子显微分析等方法,对CdS和CdSe纳米粒子的光学性质、晶体结构、形貌及尺寸等进行了表征.结果表明,当以油酸钠为稳定剂,乙醇为溶剂时,通过控制一定的前驱物浓度、反应温度和反应时间,在温和的反应条件下,可以得到尺寸分布均匀的CdS和CdSe纳米粒子,从而为在环境友好条件下合成CdS和CdSe半导体纳米粒子提供了一种新途径.     

CdS quantum dots-sensitized TiO2 nanotube arrays for solar cells

CdS quantum dots(QDs) sensitized TiO2 nanotube arrays photoelectrodes were investigated for their photovoltaic performance of quantum dots-sensitized solar cells. The highly ordered TiO2 nanotube arrays(TNAs) were synthesized on Ti foils by anodic oxidation method. Then CdS quantum dots were deposited onto the TiO2 nanotube arrays by successive ionic layer absorption and reaction(SILAR) method to serve as the sensitizers. Cd(NO3)2 and Na2S were used as the precursor materials of Cd+ and S2- ions, respectively. It is found that the CdS QDs sensitizer may significantly increase the light response of TiO2 nanotube arrays. With increasing CdS QDs deposition cycles, the visible light response increases. Maximum photocurrent was obtained for the QDs that have an absorption peak at about 500 nm. Under AM 1.5 G illuminations(100 mW cm-2), a 4.85 mA/cm2 short circuit current density was achieved, and the maximium energy conversion efficiency of the as-prepared CdS QDs-sensitized TNAs solar cells was obtained as high as 0.81 % at five SILAR cycles.     

CdSe/ZnS量子点的合成及表征

本文于水溶液中采用3-巯基丙酸作为稳定剂,成功合成了CdSe/ZnS核壳型量子点。透射电子显微镜观察表明,所合成的量子点尺寸均一,形貌近似球形,粒子大小在5 nm以下。紫外吸收光谱和荧光光谱分析表明,所合成的CdSe/ZnS核壳型量子点较之CdSe量子点更具良好光学特性。     

Experimental study on new method and automatic system for fast evaluating Al-Si alloy modification effect in front of furnace

A new method based on the surface tension measurement for fast evaluating modification effect of Al-Si alloy in front of furnace and an automatic system for fast measuring surface tension of molten Al-Si alloy are introduced. By theoretical analysis the relation between surface tension σe of molten Al-Si alloy and information parameters △P , N , φx and T has been established, namely, σ e = a △P b . N c . (φ x- φ0) d . T e . By ex- periments the relationship between surface tension and modification level of Al-Si alloy has been also got that σ e > 530 mN/m, 400 ≤σe ≤530 mN/m and σ e < 400 mN/m are corresponding with AFS 1-2, AFS 3-4 and AFS 5-6 of Al-Si modification effect. Depending on the conclusions, modification effect can be recognized in a few seconds, which is of practical significance for real-time evaluating modification effect of Al-Si alloy in front of furnace.     

Non-isothermal crystallization kinetics of kaolin modified polyester

Fiber-class modified kaolin and PET have been blended in the twin-screw and granulated to chips containing 4 wt% of kaolin.Non-isothermal crystallization process of kaolin modified polyester was investigated using a differential scanning calorimetry (DSC),and the addition of kaolin enhances either the melting temperature (Tm) or the crystallization temperature (Tc).The morphology of kaolin modified polyester,the melt of which is cooled at different cooling rate,was observed by scanning electron microscope (SEM).The relationship between Tc and cooling rate F was studied.Semi-crystalline phase t1/2 makes an exponential decline with increasing F,and the higher the cooling rate,the shorter the time of crystallization completion.Non-isothermal crystallization kinetics parameters and the activation energy were calculated,indicating that the higher rate of cooling needs the higher relative crystallinity in the unit crystallization time,the crystallization rate increased while speeding up the temperature reduction,and the activation energy ΔE was calculated to be-204.1566 kJ/mol for the non-isothermal crystallization processes by the Kissinger’s methods.     

The Optical Property of CPD Prepared CdS Films

1　IntroductionMetalchalcogenidesemiconductorsofⅡ Ⅵcom poundshavethezinc blendandwurzitestructure ,theyhavewideenergygaps (1 .7 1 3.4eV)asadirectshifttype .Hencepeopleareofgreatinterestintheapplicationofthesecompoundsinvariousoptoelectronicsdevicesand…     

Inclusion behavior of oxybutynin with hydroxypropyl-β-cyclodextrin

Inclusion behavior of oxybutynin (OBN) with hydroxypropyl-β-cyclodextrin (HP-β-CD) was investigated by ultraviolet absorption spectrum and fluorescence spectrum. A reliable determination of the complex stoichiometry was provided by the continuous variation technique. Alcohol was added to further investigate the mechanism of the inclusion behavior. Thermodynamic constants ΔG, ΔH and ΔS for inclusion interaction of OBN and HP-β-CD were determined. The results show that host-guest complex with molar ratio of 1:1 is formed, and inclusion stability constant between OBN and HP-β-CD is 54.9 L/mol determined by ultraviolet spectrum and 11.1 L/mol determined by fluorescence spectrum. OBN has weak binding ability with HP-β-CD in aqueous solution (stability constant <10² L/mol) and addition of alcohol leads to a decrease of stability constant, which indicates that the hydrophobic force contributes to the inclusion process. ΔG, ΔH and ΔS are all less than zero, which indicates that the inclusion process is a spontaneous and exothermic process.     

Effect of Pb substitution on the microstructure and ferroelectric properties of Ba<Subscript>0.7</Subscript>Sr<Subscript>0.3</Subscript>TiO<Subscript>3</Subscript> ceramic

Ferroelectric Ba0.7Sr0.3TiO3（BST） and partially Pb^2＋ substituted for Ba^2＋ ceramics （Ba0.7-xPbx）Sr0.3TiO3 （x=0.1-0.4, BPST） were prepared by using conventional solid-reaction method. XRD analysis shows that the samples microstructure changes from cubic phase to tetragonal one with the Pb^2＋ content increasing. ESEM analysis shows that the Pb^2＋ substituted samples have a denser and more uniform surface morphology than that of pure BST. Measured electrical properties suggest that the Pb^2＋ substitution for Ba^2＋ in the BST system enhances the ferroelectric performance obviously when x=0.2. In addition, the substitution increases the samples Curie temperature （To） r （Ba0.5Pb0.2）Sr0.3TiO3 ceramic has good ferroelectric properties measured at a maximal electric field of 30 kV/cm under the condition of room temperature. The corresponding saturated polarization （Ps）, remnant polarization （Pr） and coercive field （Ec） is respectively 15.687 μC/cm^2, 8.100 μ C/cm^2 and 6.611 kV/cm. The measured Tc of （Ba0.5Pb0.2）Sr0.3TiO3 is 117 ℃.     

Coating of Fe, Ni on α-alumina microspheres by heterogeneous precipitation

1INTRODUCTION Themagneticmetal coatedceramicoxides,core shellstructuralcompositematerials,inwhichthinmetallicfilmsarecoatedonaceramicoxide matrixwithmicrometerparticlesizes,areattrac tiveduetothecombinationofthefunctionalchar acteristicsofmetalsandmechanicalpropertiesoftheceramicmatrix.Theceramic basedtransition metal coated,core shellcompositessuchasNi coatedAl2O3[1],Fe coatedAl2O3[2],FeNi coated Al2O3[3]orCoFe coatedSiO2[4],havebeenfoundtoexhibitinterestingfunctionalperformancesdue…     

CdS:Co掺杂量子点的合成与表征

通过微波辐射技术,过度金属钴离子可以成功地掺杂到CdS量子点内部.由于钴离子占据了量子点的中心位置,随着辐射时间的增加,钴离子逐渐向外渗透扩散,伴随此过程,掺杂后的量子点的紫外吸收峰和荧光发射峰都相应地发生了红移.通过X射线衍射和高分辨投射电镜表征发现,掺杂后的晶体依然为立体闪锌矿结构,并且具有量子点的晶体特征;经过紫外吸收和荧光光谱表征发现,与CdS量子点相比,除了荧光光谱的发射峰范围扩宽了50 nm,荧光稳定性和化学稳定性得到了很大的提高.     

Preparation of agarose sulfate and its antithrombogenicity

As one of the seaweed polysaccharide, agarose has received much attention because of its biocompatibility. However, its application in biomedical field was limited with its biological inertia. Modification with some functional groups is needed to obtain agarose derivatives with biological activity and expand its applications. Consequently, agarose was sulfated with chlorosulfonic acid-pyridine with formamide as dispersing agent. The orthogonal test result showed that the optimal reaction condition was the reaction time being 4 h, the reaction temperature 65 ℃, and the ratio of chlorosulfonic acid to agarose 1-4(mL/g). Two kinds of the insoluble agarose sulfate (below 37 ℃) were synthesized with degree of substitution (DS) being 0.17 and 0.43 respectively. Infrared spectroscopy (IR) and 13C nuclear magnetic resonance (13C-NMR) spectroscopy results proved that C3-6 in agarose was sulfated. Their hydrophobic property and BSA adsorption capacity rose with increasing DS, while the adsorption of Hb was reduced. The anti-clotting properties of agarose sulfate were significantly improved, and agarose sulfate could protect red blood cells from deformation after adsorption of BSA. These findings demonstrate that the cold-water insoluble agarose sulfate has a promise for applications as heparin-like material in anticoagulation or endothelial regeneration scaffold.     

Effects of low dose oxymatrine on mouse lymphocyte proliferation stimulated by Con A

Objective To investigate the effects of low dose Oxymatrine (OMT) on mouse lymphocyte proliferation stimulated by Con A making use of fluorescence dyestuff (CFDA-SE). Methods CFDA-SE staining and flow cytometry were used to detect the fluorescence intensity of lymphocytes after stimulated by polyclonal stimulators Con A and OMT. Then, related software was used to analyze the effects of OMT on mouse lymphocyte proliferation. Results After cultured for 48 h, CFSE fluorescence could be detected by cytometer, filial generation peaks did not appear in control group, which indicated that lymphocytes did not proliferate. Three peaks were obviously detected in Con A group which indicated that Lymphocytes divided after 48 h stimulated by Con A compared with the halving of the fluorescence intensity of control group. In groups with Con A and OMT treated. Primary generation peaks are all lower while filial generation peaks are significantly higher than groups with Con A treated only. This indicated OMT obviously promote lymphocyte proliferation. After cultured for 72 h, the fluorescence intensity changes between all groups are consistent with those of cultured for 48 h. Analyzed with CELLQuest software, it is shown that OMT could promote lymphocyte proliferation in 16, 8, 4 and 2 μg/mL respectively. Conclusions 1)CFDA-SE dyeing and flow cytometer were both reliable tools to analyse lymphocyte proliferation; 2) lower dosage of OMT could promote the proliferation of lymphocyte as a immunopotentiator. Correspondence     

Microstructures and fatigue-free properties of the La<Superscript>3+</Superscript> and Nd<Superscript>3+</Superscript> doped Bi<Subscript>4</Subscript>Ti<Subscript>3</Subscript>O<Subscript>12</Subscript> thin films prepared by modified sol-gel technique

Ferroelectric Bi_3.25La_0.75Ti₃O₁₂ (BLT) and Bi_3.15Nd_0.85Ti₃O₁₂ (BNT) thin films were fabricated on Pt/TiO₂/SiO₂/Si (100) substrates by a modified sol-gel technique. X-ray diffraction indicated that these films were of single phase with random polycrystalline orientations. The surface morphologies of the films were observed by scanning electron microscope, showing uniform, dense films with grain size of 50–100 nm. Well-saturated hysteresis loops of the films were obtained in metal-ferroelectric-metal type capacitors with Cu top electrodes at an applied voltage of 400 kV/cm, giving the remanent polarization (2P _r) and coercive field (2E _c) values of the films of 25.1 μC/cm² and 203 kV/cm for BLT, and 44.2 μC/cm² and 296 kV/cm for BNT, respectively. Moreover, these capacitors did not show fatigue behaviors after up to 1.75×10¹⁰ switching cycles at the test frequency of 1 MHz, suggesting a fatigue-free character. The influences of the La³⁺ and Nd³⁺ doping on the properties of the films were comparatively discussed. Supported by the National Key Basic Research and Development Program of China (Grant No. 2006CB932305) and the Natural Science Foundation of Hubei Province, China (Grant No. 2004ABA082)     

Synthesis of 1,4-benzenedicarbonyl thiourea resins and their adsorption properties for Ag（I）

Several 1,4-benzenedicarbonyl thiourea resins (BTR) were synthesized through interfacial polymerization between 1,4-benzenedicarbonyl diisothiocyanate and polyamine. Their structures were confirmed by FT-IR. The adsorption properties (including the effect of adsorption time, pH, initial concentrations and temperature) of BTR-1, BTR-2 and BTR-3 for Ag(I) were investigated by batch tests. The results show that the adsorption equilibria of BTR-1, BTR-2, BTR-3 for Ag(I) are achieved after about 10 h. Their equilibrium adsorption capacities are 7.11, 6.75 and 6.23, respectively, and the adsorption process accords with G. E. Boyd equation and Langmuir adsorption isotherm as well. The adsorption capacities increase with the increase of pH (the highest uptake values are observed at pH being about 6–7). The thermodynamic parameters of BTR-1 were calculated. The results show that ΔH ^Θ; and ΔS ^Θ are 6 958.8 J/mol and 64.28 J/(mol·K), respectively, and ΔG ^Θ at 20, 30, 40 and 50 °C are −11.79, −12.52, −13.16 and −13.8 kJ/mol, respectively. The silver-loaded resins can be quantitatively eluted by a solution containing 6% thiourea in 1 mol/L HNO₃.     

Magnetic Properties of NiCuZn Ferrite Thin Films Prepared by the Sol-gel Method

Ni0.4Cu0.2Zn0.4Fe2O4 thin films were fabricated on Si substrates by using the sol-gel method and rapid thermal annealing （RTA）, and their magnetic properties and crystalline structures were investigated. The samples calcined at and above 600 ℃ have a single-phase spinel structure and the average grain size of the sample calcined at 600 ℃ is about 20 nm. The initial permeability μi, saturation magnetization M and coercivity H of the samples increase with the increasing calcination temperature. The sample calcined at 600 ℃ exhibits an excellent soft magnetic performance, which has μi=33.97 （10 MHz）, Hc=15.62 Oe and Ms=228.877 emu/cm^3. Low-temperature annealing can enhance the magnetic properties of the samples. The work shows that using the sol-gel method in conjunction with RTA is a promising way to fabricate integrated thin-film devices.     

Luminescence Characterization and Synthesis of γ-LiAlO_2:Eu~(3+) by Gel Combustion

γ-LiAlO2:Eu3+(Eu3+:LAO) phosphor was obtained by gel combustion method using LiNO3,Al(NO3)3·9H2O,Eu(NO3)3·6H2O and citric acid as raw materials.The structure,morphology and luminescence were characterized by means of X-ray diffraction (XRD),scanning electron microscopy (SEM),photoluminescence (PL).The results demonstrated that the phosphor was pure-phase of flaky tetragonal crystal system with a mean size of around 1 μm.The strongest excitation peak was at 254 nm,belonging to the broadband excitation and the maximum emission peak was at 613 nm,corresponding to the 5D0→7F2 transition of Eu3+.Luminous intensity is closely related to the calcination temperature and doping concentration of Eu3+.