weathering fur simulation

ACM SIGGRAPH; ACM SIGCHI

基于LandsatTM/ETM数据的锡林河流域土地覆盖变化

根据1987年、1991年、1997年和2000年4期LandsatTM/ETM影像的土地利用/土地覆盖分类结果,运用地理信息系统空间分析方法,分析了内蒙古锡林河流域1987~2000年间各土地利用类型及草甸草原、典型草原、荒漠草原的数量变化和空间变化特征。分析结果显示,锡林河流域土地利用/土地覆盖变化的主要特征为草甸草原、典型草原面积的大幅减少和荒漠草原、农田和沙漠化土地面积的大幅增加及城镇的扩张。其中面积增加最大的是荒漠草原,增加了2328km2;相当于1987年荒漠草原面积的56%。农田和城镇面积逐年增大,分别从1987年的114.3km2和25.2km2增加到2000年的332.1km2和43.6km2。面积减少最多的是羊草+丛生禾草、羊草+杂类草等优良高产温带典型草原类型,共减少2040km2。草甸草原面积亦呈逐年减少的趋势,从1987年的1103km2减少到2000年375km2,面积减少了65.9%。农田、沙化地及城镇等非草原土地利用类型面积增加了62.5%。

西北地区水资源安全的生态系统途径

我国西北地区是资源型缺水地区,对水资源进行科学、有效的管理无疑是该地区可持续发展的核心问题之一。在分析了生态系统管理的概念、特点、对于自然资源管理的意义,以及影响西北地区水资源安全性的生态学原因之后,提出了西北地区确保水资源安全的生态系统途径。包括:建立以流域为单元的水资源生态系统管理模式;充分利用市场机制,完善水资源管理模式;以水资源承载力和水资源安全为基础,进行西北地区的生态环境建设;加强水生态环境管理,避免因水污染造成更加严重的水危机。

Microstructures and mechanical properties of as-cast Mg–5Al–0.4Mn–xNd (x=0, 1, 2 and 4) alloys

Mg-5Al-0.4Mn-xNd (x=0, 1, 2 and 4wt.%) alloys were prepared by metal mould casting method. The microstructures and mechanical properties were investigated. The results demonstrated that Al11Nd3 phase was formed and mainly aggregated along the grain boundaries with the addition of Nd. Meanwhile, the grain sizes were greatly reduced with the increasing Nd content.

Spontaneous volume transition of polyampholyte nanocomposite hydrogels based on pure electrostatic interaction

A circular system is employed in this paper to investigate the swelling behaviors of polyampholyte hydrogels; this circular system can effectively eliminate the disturbance of various factors and keep the surrounding environment constant. It is found that there exists a spontaneous volume transition to the collapsed state of polyampholyte hydrogels, which is attributed to the overshooting effect, and the transition can occur repeatedly under certain conditions. C-13 NMR is employed to investigate the swelling behavior of polyampholyte hydrogels.

The solid-liquid extraction of yttrium from rare earths by solvent (ionic liquid) impreganated resin coupled with complexing method

A kind of solvent (ionic liquid) impreganated resin (IL-SIR) was developed herein for ameliorating imidazolium-type IL-based liquid-liquid extraction of metal ions. In this study, [C(8)mim][PF6] containing Cyanex923 was immobilized on XAD-7 resin for solid-liquid extraction of rare earth (RE). The solid-liquid extraction contributed to ameliorating mass transfer efficiency, i.e. shortening equilibrium time from 40 min to 20 min, increasing extraction efficiency from 29% to 80%. In additional, the novel IL-SIR could separate Y(III) from Sc(III), Ho(III), Er(III), Yb(III) effectively by adding water-soluble complexing agent.

马钱苷的电喷雾串联质谱及傅立叶变换离子回旋共振质谱研究

利用电喷雾串联质谱(ESI-MSn)技术研究马钱苷的质谱碎裂机理,探讨其碎裂方式,并利用傅立叶变换离子回旋共振质谱(FTICR-MS)及SORI-CID高分辨率、高质量准确度对其碎裂机理进行验证研究。采用H/D交换和串联质谱的方法,发现马钱苷羟基上的活泼氢在质谱中性碎片丢失过程中较易被转移,表现出较大的化学活性。通过加入特定的Na+和Li+等碱金属离子,极大地提高了马钱苷化合物质谱分析的灵敏度,获得了更多的结构信息,建立了马钱苷化合物质谱鉴定和分析的新方法。

Hollow DNA/PLL microcapsules with tunable degradation property as efficient dual drug delivery vehicles by alpha-chymotrypsin degradation

Hollow deoxyribonucleic acid (DNA)/poly-L-lysine (PLL) capsules were successfully fabricated through a layer-by-layer (LbL) self-assembly of DNA and PLL on porous CaCO3 microparticles, followed by removal of templates with ethylenediamine tetraacetic acid disodium salt (EDTA). The enzymatic degradation of the capsules in the presence of alpha-chymotrypsin was explored. The higher the enzyme concentration, the higher is the degradation rate of hollow capsules. in addition, glutaric dialdehyde (GA) cross-linking was found to be another way to manipulate degradation rate of hollow capsules.

Removal of Cr(III, VI) by quaternary ammonium and quaternary phosphonium ionic liquids functionalized silica materials

A series of silica-based organic–inorganic hybrid materials were prepared by the sol–gel process for Cr(III) and Cr(VI) adsorption. These silica materials generally had high surface areas, good physical–chemical stability and high thermal stability. Trialkylmethylammonium bis 2,4,4-trimethylpentylphosphinate ([A336][C272]) and trihexyl(tetradecyl)phosphonium bis 2,4,4-trimethylpentylphosphinate (Cyphos IL 104) were explored as porogens to prepare porous silica and as extractants to extract chromium ions. Cyphos IL 104 and [A336][C272] functionalized silica sorbents (SG-2, SG-5) can be effectively used for the removal of Cr(III) and Cr(VI) from aqueous solutions by adjusting pH values, whereas trialkylmethylammonium chloride (Aliquat 336) and bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) functionalized silica sorbents (SG-3, SG-4) can only be used for the removal of the single chromium species, Cr(VI) or Cr(III).

Separation of scandium(III) from lanthanides(III) with room temperature ionic liquid based extraction containing Cyanex 925

The separation of Sc(III) from Y(III), La(III) and Yb(III) in [C(8)mim][PF6] containing Cyanex 925 has been investigated, and is reported in this paper. A cation exchange mechanism of Sc(III) in [C(8)mim][PF6] and Cyanex 925 is proposed by study of the influence of anionic and cationic species on the extraction. The coefficient of the equilibrium equation of Sc(III) was confirmed by slope analysis of log D-Sc vs log [Cyanex 925], and the loading capacity also confirmed the stoichiometry of Cyanex 925 to Sc(III) was close to 3:1. Infrared data for Cyanex 925 saturated with Sc(III) in [C(8)mim][PF6] indicated strong interaction between P=O of Cyanex 925 and Sc(III). In addition, the relationship between log D-Sc and temperature showed that temperature had little influence on the extraction process, and the resulting thermodynamic parameters indicated that an exothermic process was involved.

Organic photovoltaic cells using hexadecafluorophthalocyaninatocopper (F16CuPc) as electron acceptor material

We fabricated organic photovoltaic cells by using hexadecafluorophthalocyaninatocopper (F16CuPc) as electron acceptor material and para-sexiphenyl (p-6P) as electron donor material. F16CuPc has wide absorption spectrum from 550 nm to 850 nm, which covers the maximum of solar photo flux. The measurement of their external quantum efficiency (EQE) demonstrated that the photocurrent comes from the excitons created in F16CuPc, which were separated into free electrons and holes at heterojunction interface of p-6P and F16CuPc. Moreover, F(16)FuPc with excellent air-stability improved the environmental stability of photovoltaic cells, and the unencapsulated cells exhibited the shelf lifetime of exceeding a week.