长株潭地区可持续发展的综合评价——基于“两型社会”建设的视角

参照国内外现有的可持续发展指标体系,基于"两型社会"建设的视角,根据长株潭地区的具体特征以及数据的可得性,建立了包含经济社会与资源环境2个一级指标21个二级指标的长株潭可持续发展指标体系,并采用2000到2011年年度数据对长株潭地区可持续发展进行了评估与分析.研究结果显示,长株潭地区的生态环保指标综合得分已从2004年前的小于经济社会指标综合得分变为当前的大于经济社会指标综合得分;地区可持续发展度已从2000年前的非可持续逐渐过渡到现在的接近高可持续性,意味着"两型社会"第一阶段的各项目标任务已基本完成.但产业转型难将会成为长株潭整体辐射区生态环境优化的重要瓶颈.     

Synthesis of mesoporous γ-alumina by sol–gel process and its characterization and application for sorption of Pu(IV)

Mesoporous γ-alumina samples were prepared by the sol–gel process from the boehmite sol having different template solutions. Copper doped material was also prepared from sol containing template solution along with copper nitrate. Studies were performed to understand the influence of templates on the morphology of the synthesized samples particularly with respect to specific surface area and porosity. Synthesized samples were used to study sorption of Pu(IV) from nitric acid–oxalic acid solutions. Distribution ratios (D) for Pu(IV) were determined using the γ-alumina samples with an objective to employ these for the recovery of Pu.     

HPTLC Densitometric Quantification of Hydrolyzable Tannins from Triphala churna

JPC – Journal of Planar Chromatography – Modern TLC - A simple high-performance thin-layer chromatographic (HPTLC) method has been established for simultaneous quantification of...     

Optical transmission through double-layer metallic subwavelength slit arrays

We present measurements of transmission of infrared radiation through double-layer metallic grating structures. Each metal layer contains an array of subwavelength slits and supports transmission resonance in the absence of the other layer. The two metal layers are fabricated in close proximity to allow coupling of the evanescent field on individual layers. The transmission of the double layer is found to be surprisingly large at particular wavelengths, even when no direct line of sight exists through the structure as a result of the lateral shifts between the two layers. We perform numerical simulations using rigorous coupled wave analysis to explain the strong dependence of the peak transmission on the lateral shift between the metal layers.     

Enhancement of second harmonic generation efficiency: Cs(I)-doped tris(thiourea)zinc(II) sulphate crystals

The effect of dopant cesium (Cs(I)) over a concentration range from 1 to 10 mol% on the growth process, morphology, thermal and optical properties of tri(thiourea)zinc(II) sulfate (ZTS) single crystals grown by slow evaporation solution growth technique has been investigated. Incorporation of Cs(I) into the crystal lattice was well confirmed by energy dispersive X-ray spectroscopy (EDS). The lattice parameters of the as-grown crystals were obtained by single crystal X-ray diffraction analysis. The reduction in the intensities observed in powder X-ray diffraction patterns of doped specimen and slight shifts in vibrational frequencies in fourier transform infrared spectra (FT-IR) indicate the lattice stress as a result of doping. Thermal studies reveal the purity of the material and no decomposition is observed up to the melting point. High transmittance is observed in the visible region and the cut-off λ is ～280 nm. The surface morphology of the as-grown specimens was studied by scanning electron microscopy (SEM). The second harmonic generation (SHG) efficiency of the host crystal is enhanced greatly in the presence of high concentrations of the dopant.     

考虑微结构连接性的双尺度结构自然频率拓扑优化

多孔材料因具有轻量化、高孔隙率和减振/散热等优良多物理特性,在航空航天等领域具有广阔应用前景。采用拓扑优化方法对含多种多孔材料的结构进行结构与材料微结构构型一体化设计,有助于获得具有优良力学性能的结构设计。然而,传统逆均匀化微结构设计方法无法确保不同多孔材料微结构之间的连接性,设计结果不具备可制造性。本文面向含多种多孔材料的双尺度结构基频最大化设计问题,考虑不同微结构之间的连接性,协同设计多孔材料的微结构构型及其在宏观尺度下的布局。采用均匀化方法计算多孔材料的宏观等效力学性能,通过对不同多孔材料微结构单胞的边界区域采用相同的拓扑描述确保双尺度优化过程中任意空间排布下不同微结构的连接性,并通过优化算法确定微结构间的连接形式及微结构拓扑。在宏观尺度,提出结合离散材料插值模型和RAMP插值模型RAMP (Rational Approximation of Material Properties)的多孔材料各向异性宏观等效刚度及质量插值模型,获得清晰的多孔材料宏观尺度布局并减轻优化过程中伪振动模态的影响。建立以双尺度结构基频最大化为目标,以材料用量为约束的优化列式,推导灵敏度表达式,并基于梯度优化算法求解双尺度结构拓扑优化问题。数值算例表明,采用本文优化方法能够有效确保基频最大化双尺度结构设计中不同多孔材料微结构之间的连接性,增强优化设计结果的可制造性。