岷江上游居民点分布格局及影响因子分析

为了研究岷江上游居民点格局及其影响因子,利用1:25万基础地理信息数据和统计数据,在GIS的支持下,对居民点空间格局以及影响因子进行了较为深入的研究。结果表明:(1)研究区大散居、小聚居的农村居民点特征显著。(2)居民点分布主要集中在河流与道路的两侧,属于典型的高山峡谷地带居民点分布;居民点离散特征不显著。(3)居民点分布与海拔存在一种非线性的关系。研究成果为进一步分析人口的分布格局与人口数据空间化;实现生态退耕,区域景观格局优化以及区域可持续发展提供重要的依据。

中国区域可持续发展状态及类型划分

可持续发展的内涵就是人口、资源和环境的相互协调 ,目的是谋求社会和经济的持续发展。区域作为可持续发展的载体 ,在实施可持续发展战略中占据重要地位 ,它具有明显的区域性、复杂性和相对性等特征。影响区域可持续发展的主要因素有经济发展状况、社会发展状况、资源环境状况和可持续发展能力 ,据此 ,本文建立了区域可持续发展状态评价指标体系 ,对中国 31个省市区的可持续发展状态进行了评价 ,按照评价结果 ,全国共分为 6种不同类型 ,并得出中国区域可持续发展状态大体呈从沿海→沿边→中部→中西部递减的结论

居民对改善城市水环境支付意愿的研究

运用条件价值评估法,对银川市居民为改善水环境的支付意愿及其影响因素作了初步分析。计算结果显示,研究范围内的居民年平均支付意愿约为17555元/户。回归分析表明,居民家庭年平均收入、教育水平、对现状水环境的满意程度和对供水部门的信任程度等因素对支付意愿有显著影响。

红壤丘陵区双季稻表观光合量子效率的研究

研究结果表明红壤丘陵区双季稻光光合速率响应曲线符合非直角双曲线函数,水稻旗叶、倒2叶和倒3叶表观初始光能利用效率平均值(±标准差)分别为0.0536(±0.023)、0.0511(±0.023)和0.0488(±0.025),即由旗叶向下递减;水稻光合作用最适温度为27～30℃。

Structures and electrochemical characteristics of Ti0.26Zr0.07V0.24Mn0.1Ni0.33Mox (x=0-0.1) hydrogen storage alloys

Microstructures and electrochemical properties of Ti0.26Zr0.07V0.21Mn0.1Ni0.33Mox (x=0,0.025,0.05,0.075, 0.10) electrode alloys have been investigated. The results of XRD analysis show that the alloys are mainly composed of V-based solid solution phase with body centered cubic (bcc) structure and C14 Laves phase with hexagonal structure. The addition of Mo element can imp ove the activation characteristics, maximum discharge capacity and cyclic durability for the electrode alloys

白光有机发光二极管的制备方法

有机发光二极管(OLEDs)以其制备工艺简单、成本低、发光颜色可在可见光区内任意调节、易于大面积制作和可制成柔性器件等优点,被认为是未来重要的显示技术之一,在照明光源领域也显示了诱人的应用前景。文章阐述了实现白光OLEDs的方法及其近期进展,并结合自身工作介绍了白光OLEDs的制备方法,最后对白光OLEDs目前存在的问题及其发展趋势进行了讨论。

Luminescence functionalization of SBA-15 by YVO4 : Eu3+ as a novel drug delivery system

Luminescence functionalization of the ordered mesoporous SBA-15 silica was realized by depositing a YVO4:Eu3+ phosphor layer on its surface via the Pechini sol-gel process, resulting in the formation of the YVO4:Eu3+@SBA-15 composite material. This material, which combines the mesoporous structure of SBA-15 and the strong red luminescence property of YVO4:Eu3+, can be used as a novel functional drug delivery system. The structure, morphology, porosity, and optical properties of the materials were well characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, N-2 adsorption, and photoluminescence spectra. As expected, the pore volume, surface area, and pore size of SBA-15 decrease in sequence after deposition of the YVO4:Eu3+ layer and the adsorption of ibuprofen (IBU, drug). The IBU-loaded YVO4:Eu3+@SBA-15 system still shows the red emission of Eu3+ (617 nm, D-5(0)-F-7(2)) under UV irradiation and the controlled drug release property. Additionally, the emission intensity of Eu3+ increases with an increase in the cumulative released amount of IBU in the system, making the extent of drug release easily identifiable, trackable, and monitorable by the change of luminescence. The system has great potential in the drug delivery and disease therapy fields.

Host-sensitized luminescence of Dy3+, Pr3+, Tb3+ in polycrystalline SrIn2O4 for field emission displays

SrIn2O4:Dy3+/Pr3+/Tb3+ white/red/green phosphors were prepared by the Pechini sol-gel process. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), diffuse reflectance, photoluminescence, cathodoluminescence spectra, and lifetimes were utilized to characterize the samples. XRD reveal that the samples begin to crystallize at 800 degrees C and pure SrIn2O4 phase can be obtained at 900 degrees C. FE-SEM images indicate that the SrIn2O4:Dy3+, SrIn2O4:Pr3+, and SrIn2O4:Tb3+ samples consist of fine and spherical grains with size around 200-400 nm. Under the excitation of ultraviolet light and low-voltage electron beams (1 - 5 kV), the SrIn2O4:Dy3+, SrIn2O4: Pr3+, and SrIn2O4: Tb3+ phosphors show the characteristic emissions of Dy3+ (F-4(9/2) - H-6(15/2) at 492 nm and 4F(9/2) - 6H(13/2) at 581 nm, near white), Pr3+ (P-3(0) - H-3(4) at 493 nm, D-1(2) - H-3(4) at 606 nm, and P-3(0) - H-3(6) at 617 nm, red) and Tb3+ (D-5(4) - F-7(6,5,4,3) transitions dominated by D-5(4) - F-7(5) at 544 nm, green), respectively. All of the luminescence resulted from an efficient energy transfer from the SrIn2O4 host lattice to the doped Dy3+, Pr3+, and Tb3+ ions, and the luminescence mechanisms have been proposed.

Deposition of GdVO4 : Eu3+ nanoparticles on silica nanospheres by a simple sol-gel method

The deposition and coating of GdVO4: Eu3+ nanoparticles on spherical silica was carried out using a simple sol - gel method at low temperature. The GdVO4: Eu3+-coated silica composites obtained were characterized by differential thermal analysis (DTA), thermogravimetric (TG) analysis, x-ray diffraction (XRD), Fourier-transform IR spectroscopy (FT-IR), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), photoluminescence spectra, and kinetic decay. It is found that the similar to 5 nm GdVO4: Eu3+ nanoparticles coating the silica spheres are crystal in the as-prepared samples and the crystallinity increases with increasing annealing temperature. The composites obtained are spherical in shape with an average size of 100 nm. The GdVO4: Eu3+ nanoparticles are linked with silica cores by a chemical bond. The photoluminescence spectra of the obtained GdVO4: Eu3+-coated silica composites are similar to those of the bulk GdVO4: Eu3+ phosphors. The strongest peak is near 617 nm, which indicates that Eu3+ is located in the low symmetry site with non-inversion centre.

Novel heteroleptic Cu-I complexes with tunable emission color for efficient phosphorescent light-emitting diodes

A series of orange-red to red phosphorescent heteroleptic Cu-I complexes (the first ligand: 2,2 '-biquinoline (bq), 4,4 '-diphenyl2,2 '-biquinoline (dpbq) or 3,3 '-methylen-4,4 '-diphenyl-2,2 '-biquinoline (mdpbq); the second ligand: triphenylphosphine or bis[2-(diphenylphosphino)phenyl]ether (DPEphos)) have been synthesized and fully characterized. With highly rigid bulky biquinoline-type ligands, complexes [Cu(mdpbq)(PPh3)(2)](BF4) and [Cu(mdpbq)(DPEphos)](BF4) emit efficiently in 20 wt % PMMA films with photoluminescence quantum yield of 0.56 and 0.43 and emission maximum of 606 nm and 617 nm, respectively. By doping these complexes in poly(vinyl carbazole) (PVK) or N-(4-(carbazol-9-yl)phenyl)-3,6-bis(carbazol-9-yl) carbazole (TCCz), phosphorescent organic light-emitting diodes (OLEDs) were fabricated with various device structures. The complex [Cu(mdpbq)(DPEphos)](BF4) exhibits the best device performance. With the device structure of ITO/PEDOT/ TCCz:[Cu(mdpbq)(DPEphos)](BF4) (15 wt %)/TPBI/LiF/Al (III), a current efficiency up to 6.4 cd A(-1) with the Commission Internationale de L'Eclairage (CIE) coordinates of (0.61, 0.39) has been realized. To our best knowledge, this is the first report of efficient mononuclear Cu complexes with red emission.

下沉液态阴极电解制备镁—稀土中间合金系列的研究

本文采用下沉液态阴极电解法,在KCl·NaCl-RECl<,3>体系中,电解制备镁-稀土中间合金,研制了Mg-Y,Mg-富Y;Mg-Nd,Mg-富Nd;Mg-Ce,Mg-富Ce;Mg-La,Mg-镧镨铈新型混合稀土等系列合金产品,并对合金的成分、熔点做了初步分析.提出了较理想的电解质熔体及电解工艺.

Surface morphology evolution of thin triblock copolymer films during spin coating

The surface morphology evolution of thin poly(styrene-block-ethylene/butylenes-block-styrene) (SEBS) triblock copolymer films as a function of the copolymer concentration was investigated by means of dynamic mode atomic force microscopy. At a relatively low copolymer concentration (0.025% w/v), the periodically orientated stripes were observed. This kind of surface patterning produced in the spin-coating process has not been reported in the literature before. It has been shown by our experiment that a shearing and stretching field can cause flexible polymer coils or aggregates to orientate during the spin coatings At a copolymer concentration of 0.05% w/v, SEBS molecule aggregates form network structures in the whole film. With further increase of the copolymer concentration, a continuous film with a microphase-separated structure was visualized.