A yolk-shell nanoreactor with a basic core and an acidic shell for cascade reactions

Smart yolk-shell nanoparticles (hollow nanoparticles with a movable core) with an acidic shell and a basic core were fabricated through an organosilane-assisted selective etching method and acted as efficient nanoreactors for catalyzing a deacetalization-Henry cascade reaction with high activity and high selectivity. This strategy is very promising for the design of multifunctional nanoreactors for cascade reactions.     

Analytical control of molecular excitations including strong field polarization effects

An analytical scheme is presented for designing a laser pulse to excite H2 from one specified vibrational-rotational state to another. The scheme is based on an adiabatic two-state approximation in a Floquet picture. By continuously and smoothly changing the laser frequency, we explicitly harness the dynamic Stark shifts and maintain resonance between the dressed diabatic states during laser-molecule interaction. The explicit time-dependent solution of the Schr?dinger equation confirms the validity and efficacy of the analytically designed laser pulses. The scheme depends on the molecular polarizability to achieve its control objectives.     

Study on electro-conductance and thermal analysis of lithium carnallite

Lithium carnallite is a hydrated double salt containing lithium and magnesium chlorides. The processes of thermal dehydration and thermal decomposition of lithium carnallite during heating has been studied by the conductance-thermoanalysis which was designed according to Berg and-Wendlandt, and an interpretation of the conductance-thermoanalytical curve has been suggested.     

Studies on synthesis, characterization and thermochemistry of Mg2[B2O4(OH)2]·H2O

A new magnesium borate Mg₂[B₂O₄(OH)₂]·H₂O has been synthesized by the method of phase transformation of double salt at hydrothermal condition and characterized by XRD, IR, TG and DSC. The enthalpy of solution of Mg₂[B₂O₄(OH)₂]·H₂O in 0.9764 mol L^–1 HCl was determined. With the incorporation of the enthalpies of solution of H₃BO₃ in HCl (aq), of MgO in (HCl+H₃BO₃) (aq), and the standard molar enthalpies of formation of MgO(s), H₃BO₃(s), and H₂O(l), the standard molar enthalpy of formation of –(3185.78±1.91) kJ mol^–1 of Mg₂[B₂O₄(OH)₂]·H₂O was obtained.This revised version was published online in November 2005 with corrections to the Cover Date.     

盐卤硼酸盐化学——Ⅺ.不同含硼浓缩盐卤的稀释实验

前文[1]报道高含硼浓缩盐卤加水稀释过程中硼酸盐的行为。考虑到青海省柴达木盆地大柴旦盐湖卤水日晒蒸发到钾盐析出阶段,浓缩卤水中含1.87％MgB_4O_7,蒸发到水氯镁石开始析出,浓缩卤水中含2.95％MgB_4O_7。本文报道,这两种不同含硼浓缩卤水按文献[1]中实验步骤进行加水稀释,室温放置过程中析出硼酸镁盐的某些不同结果。     

Volumetric Properties and Volumetric Interaction Parameters of the CsCl‐saccharides (D‐glucose,D‐fructose)‐water Solutions at 298.15 K

Densities have been measured for the CsCl‐saccharide (D‐glucose, D‐fructose)‐water systems at 298.15 K. These data were used to calculate the apparent molar volume of CsCl (V_φ,E) and the saccharides (V_φ,S), and the infinite dilution apparent molar volume V_φ,E⁰ and V_φ,S⁰ in the studied solutions. In addition, the standard transfer volume Δ_tV_φ,E⁰ of CsCl from water to aqueous saccharides solutions, and Δ_tV_φ,S⁰ of saccharides from water to CsCl solutions have been evaluated and discussed using the structural interaction model. The volumetric interaction parameters for CsCl with saccharide in water were obtained and analyzed by the group additivity principle and the stereochemistry of the saccharide molecules.     

点火靶驱动不对称性与表面粗糙度的模耦合模拟

使用二维辐射多群扩散流体力学程序LARED-S对点火靶内爆进行大规模数值模拟,同时考虑低阶辐射驱动不对称性和中高阶的表面粗糙度.计算结果表明：靶丸内爆流场不仅出现严重的低阶模面密度扰动,同时生成大幅度的尖钉与气泡结构;呈现明显的扰动模耦合效应,模耦合生成的扰动增长幅度与理论公式在一定时间内较好地吻合.在内爆减速阶段,扰动增长发展到强非线性阶段,模耦合效应使得扰动频谱分布变宽;同时芯部的涡流使得靶壳的尖钉弯曲,内爆流场出现明显的湍流混合现象.模耦合效应与湍流混合极大地降低了内爆性能,导致点火失败.     

盐卤硼酸盐化学——Ⅺ.不同含硼浓缩盐卤的稀释实验

In this paper, we have studied on the behaviour of borate during dilution of different boron-containing concentrated brines in which the boron-concentrations are lower than that brine used in the article reported and obtained some interesting results which have never found in any reference before.     

Encapsulation of chiral Fe(salan) in nanocages with different microenvironments for asymmetric sulfide oxidation

The solid catalysts for asymmetric oxidation of sulfides were prepared by encapsulating a chiral iron salan complex [Fe(salan)] in the nanocages of mesoporous silicas. The microenvironment of nanocages was finely tuned using silylation reagents with different kinds of organic groups, such as propyl (C3), 1-butyl-3-propyl-4,5-dihydroimidazolium bromide (ILBr), N-propyl-N,N,N-tri-n-butylammonium chloride (TBNCl) and N-propyl-N,N,N-tri-n-butylammonium bromide (TBNBr), and investigated by water and benzene adsorption. Fe(salan) encapsulated in the amphiphilic nanocage shows much higher enantioselectivity and activity than that in hydrophobic or hydrophilic nanocage for the asymmetric oxidation of thioanisole using H(2)O(2) as oxidant. The TOF of Fe(salan) encapsulated in the nanocage modified with TBNBr can reach as high as 220 h(-1), even higher than homogeneous Fe(salan) with a TOF of 112 h(-1). The enhanced catalytic activity is mainly due to the fast diffusion of H(2)O(2) and sulfide in the amphiphilic nanocage. The above results suggest that the microenvironment modification of the nanocage is an efficient method to synthesize highly efficient solid catalysts for asymmetric catalysis.     

高分子热活化延迟荧光材料研究进展

高分子热活化延迟荧光材料能够利用热活化的反向系间窜越过程将三线态激子转变为单线态激子而发出荧光,理论上可以实现100%的内量子效率,突破了传统高分子荧光材料内量子效率不超过25%的极限,因而代表了未来低成本高效率高分子发光材料的发展方向。 近年来,高分子热活化延迟荧光材料在分子设计方面取得了重要进展,形成了主链型、侧链型和树枝状高分子热活化延迟荧光材料等材料体系,同时其器件性能得到了大幅提升,部分材料的器件效率达到了高分子磷光材料的水平。 本文从材料和器件两个方面,围绕高分子热活化延迟荧光材料的分子结构、光物理特性和器件性能,总结和评述了国内外研究者在该领域方向的研究进展,并分析了未来发展面临的机遇和挑战。