Study of composition and structure of aluminum phosphate binder

In this article, theoretical analysis and different testing techniques were used to study the reaction pathways and synthesized products of phosphoric acid and aluminum hydroxide at different Al/P molar ratios. The results show that: (a) When the molar ratio of phosphoric acid/aluminum hydroxide is 1:3, the reaction will produce stoichiometric aluminum dihydrogen phosphate (Al(H₂PO₄)₃); (b) when Al(OH)₃ is excessive, an intermediate, monohydroxy aluminum dihydrogen phospate (HO-Al-(H₂PO₄)₂), will appear, which is unstable and will continue to react according to two reaction pathways, one is intramolecular dehydration to form phosphoric acid hydrogen-dihydrogen aluminum diphosphate (H₂PO₄)Al(HPO₄); the other is intermolecular dehydration cross-linking to form a polymeric macromolecular aluminum phosphate H-((HPO₄)(H₂PO₄)Al-O-HPO₄-Al(H₂PO₄)-O)- _nH. The ratio of the two pathways is affected by the excess of Al(OH)₃. When the excess of Al(OH)₃ continues to increase, the ratio of the second reaction path begins to increase and the viscosity of the product gradually increases. Adhesion experiments show that the aluminum dihydrogen phosphate has the best bonding performance benefiting from its lower viscosity.     

Synthesis and photoluminescence characteristics of (Sr, Ca)3B2O6:Eu for application in white light-emitting diodes

A series of yellow-green (Sr, Ca)₃B₂O₆:Eu phosphors have been synthesized using precursors prepared via a facile sol-gel route. The solid-solution phases crystallized to materials with the formula of Sr_3−x−yCa_xEu_yB₂O₆ with varied Ca²⁺ and Eu²⁺ contents. The emission peak centered at 540 nm under near-UV excitation exhibited a broad-band distribution in the range of 450-650 nm. The dependences of the luminescence intensity on the contents of Ca²⁺ substitution and Eu²⁺ dopant were also investigated. The composition in the host lattice sensitively affected the chromaticity index. Sr_1.21Ca_1.7Eu_0.09B₂O₆ (SCB:0.09Eu) was shown to possess the highest intensity and broadest emission band. Calcining temperature was shown to greatly influence the luminescent properties of SCB:0.09Eu. It is concluded that SCB:0.09Eu can be used as an efficient yellow-green phosphor for white light-emitting diodes (white LEDs) applications.     

Structural and optical properties of the nanopowder of the Eu3+ doped LiLaP4O12 produced by sol gel route

Structural and optical properties of nanopowders of Eu³⁺-doped LiLaP₄O₁₂ (LiLaPO) were studied. The samples were synthetized via polyvinyl alcohol assisted sol gel method. Powder X-ray diffraction (XRD) results showed that the samples have the LiLaPO crystalline phase and scanning electron microscopy (SEM) showed that the particles are in the nanometer scale, mostly as isolated particles with same aggregates. Photoluminescence (PL) properties were evaluated via excitation and emission spectra. The excitation spectra, in the range 2.6–13.8 eV, allowed the identification of the charge transfer band, 4f → 4f5d excitation, exciton formation and the interband excitation of the Eu³⁺ ions in the matrix. The emission spectra revealed that Eu³⁺ is located in two different sites in the samples, one of them being at the bulk and the other close to the surface of the nanoparticles, result confirmed by the CT excitation band.     

一种面向监测区域的链路质量和覆盖保证的节点调度算法

为了降低监测区域能耗总开销和减少网络传输时延,保证监测区域网络链路质量、实现网络的全面覆盖和延长网络生命周期,设计了一种基于扫描线和节点自适应调整苏醒时隙的节点调度方案。首先,定义了系统模型即网络假设和调度目标;然后判断网络是否实现当完全覆盖,当不能全面覆盖时,通过调整部分节点的感知半径来实现网络的全面覆盖;当链路质量过差导致传输延迟过大时,通过设计从源节点到目标节点的增加节点苏醒时隙,并根据节点的剩余能量和传输延迟阈值来减少数据传输次数以降低传输延迟。在NS2环境下进行实验,结果表明：文中方法能有效地实现传感器网络监测区域的全面覆盖,降低网络的传输延迟和提高网络的生命周期,与其他节点调度相比,具有很强的优越性和实用性。     

Nanopatterned Electrochromic Conjugated Poly(terthiophene)s via Thermal Nanoimprint Lithography of Precursor Polymer

Polyterthiophene nanostructures consisting of periodic nanolines were prepared using the precursor polymer approach in conjunction with nanoimprint lithography. Precursor polynorbornylenes consisting of terthiophene side chains were prepared from their corresponding norbornylene monomers via ring opening metathesis polymerization. A copolymer consisting of terthiophene norbornylene and acetate norbornylene repeat units with a 50:50 composition exhibited a glass transition temperature of 52°C. Nanolines of percursor polynorbornylene were prepared by thermal nanoimprint lithography. The nanoimprinted precursor polymer was then converted to conjugated conductive polymer via chemical and electrochemical oxidation of the terthiophene side units. Nanoimprinted lines of conductive polyterthiophene exhibited high electrochromic contrast at 437 nm.     

Crystal Structure and Raman Spectroscopic Study of K5[CuO2][CO3]

Air and moisture sensitive K₅[CuO₂][CO₃] was prepared via the azide/nitrate route from stoichiometric mixtures of the precursors CuO, KN₃, KNO₃ and K₂CO₃. According to the single‐crystal X‐ray analysis of the crystal structure [P4/nbm, Z = 2, a = 7.4067(5), c = 8.8764(8) Å, R₁ = 0.053, 433 independent reflections] K₅[CuO₂][CO₃] represents an ordered superstructure of Na₅[NiO₂][CO₃]. The structure contains isolated [CuO₂]^3– dumbbells and CO₃^2– anions, with the latter not connected to the transition element. Raman spectroscopic measurements confirm the presence of CO₃^2– in the structure.     

LaF3纳米片和棒束的选择性合成及表征

室温条件下,以简单的液相法,通过改变氟源NaBF4和K2SiF6,制得不同形貌的LaF3纳米晶(片及棒束).X射线衍射(XRD)结果显示所得的2种不同形貌的产物均为结晶良好的六方相LaF3.场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)结果表明由NaBF4制得大量均匀、厚度约为20 am的六边形纳米片....     

The role of potassium tellurite as tellurium source in mercaptoacetic acid-capped CdTe nanoparticles

Water-soluble CdTe nanoparticles were synthesized in aqueous solution with the assistance of mercaptoacetic acid (MAA) molecules by wet chemical route and microwave-assisted method. A series of cadmium telluride (CdTe) nanoparticles capped with a bifunctional molecule, which contains both thiols and carboxylic acid groups were prepared using different pH values and using potassium tellurite as tellurium source. Thiol-capped nanocrystals of CdTe can be isolated as powders using 2-propanol. The synthesized thiol-capped CdTe were characterized with EDAX, TEM, Raman, FT–IR, UV–Visible absorption, fluorescence spectroscopy and X-ray diffraction (XRD) for the particle size determination and to understand their optical properties. The particles crystallize predominantly in cubic phase with narrow photoluminescence emission. Potassium tellurite as source of tellurium improves the photoluminescence efficiency and also avoids the cumbersome processes associated with H₂Te or NaHTe sources.     

氨丙基官能化HMS介孔分子筛的合成及表征

沿S0I0路径,以十六胺为模板剂,以3-氨丙基三乙氧基硅烷为有机硅源,通过与TEOS共水解沉淀合成了氨丙基官能化HMS介孔分子筛.采用粉末X-射线衍射分析、N2吸/脱附、扫描电镜分析、高分辨透射电镜分析、傅立叶变换红外分析以及元素分析等表征手段,对所合成的材料进行表征.氨丙基官能化HMS介孔分子筛具有worm-like孔道结构,且较为均一的孔径分布.研究了前体硅源中3-氨丙基三乙氧基硅烷含量的变化对氨丙基官能化HMS介孔分子筛的相结构及织构性能的影响.傅立叶变换红外分析表明,NH2-CH2-CH2-CH2有机基团分布在杂化HMS介孔孔道中.     

Mathematical modeling and solution trajectories of complex chemical mechanism based on Monte Carlo methods

The main purpose of this article is introducing the method of Spectral Quasi Equilibrium Manifold taking different model, simple and complex mechanism to find solution curve. Before that discussing reaction kinetic, reduction of system, chemical equilibrium, QEM technique. As in complex reaction we need to split reaction mechanism in different route to reduce the complexity of higher dimensional system.in this article SQEM technique is apply to different route and comparison of route is also discussed. In previous years, the depiction of existing method based on chemical reaction kinetics has become a standard approach, for which estimation of involved parameters become challenge. For the model developments and standardization, Sensitivity analysis is powerful tool. Influence of parameters on target output is discussed through graphical results.