Late cenozoic chemical weathering and environmental changes recorded in the Co Ngoin sediments, central Qinghai-Tibet Plateau

IEECAS SKLLQG

腐植酸成就三十年祝词

<正>腐植酸是土壤肥力的挚友。腐植酸进入于食物链,让土壤更肥沃,让食物更安全,让生活更美好。腐植酸的羧基、酚羟基、醌基等活性基团,决定了腐植酸具有弱酸性、亲水性、离子

黄土高原土壤水资源与植树造林

论文在对黄土高原土壤水分资源的赋存条件和土壤水分循环与平衡分析基础上， 讨论了人工林系统的土壤水文效应、 土壤干燥化──土壤干层的形成与植树造林问题。

卡通化图像和视频的毛发纹理生成与替换

低成本卡通制作中的图像和视频通常缺乏对动物角色毛发效果的表现,为了能对已有图像及视频中的动物角色进行处理,为其增添具备真实感的毛发效果,提出一种毛发风格化算法——卡通化毛发纹理算法.针对卡通中的动物角色合成毛发纹理并进行替换,分为图像应用及视频应用2个部分.在图像替换时,对要进行风格化处理的目标区域进行图像结构分析,以获取覆盖目标区域的三角网格,再生成毛发纹元并映射于网格之上,通过绘制纹元来生成具备真实感的毛发效果;在进行视频替换时,提取视频关键帧并基于图像应用算法生成相应的卡通化毛发纹理进行图像替换,之后根据关键帧的替换结果指导整个视频的替换.为了获取随时间变化的图像关键帧目标区域,采用SIFT算法计算特征点在时间轴上的匹配;为了快速合成卡通化毛发纹理,采用基于GPU的光线行进算法加速毛发纹元的体绘制过程.实验结果表明,文中算法可成功地对已有图像及视频的动物角色添加具备真实感的毛发效果.

Nonisothermal crystallization behavior of poly (L-lactide)-poly(ethylene glycol) dibloick copolymer

The nonisothermal crystallization behavior of poly (L-lactide)-poly(ethylene glycol) ( PLLA-PEG) diblock copolymer was studied by means of real-time WAXD, DSC and POM, and Ozawa equation was used to analyze the kinetics of PLLA-PEG under nonisothermal crystallization conditions. During the crystallization of the high-T-m block (PLLA), the low-T-m block (PEG) acts as a noncrystalline diluent, and the crystallization behavior of PLLA obeys the Ozawa theory. When the PEG block begins to crystallize, the PLLA phase is always partially solidified and the presence of the spherulitic microstructure of PLLA profoundly restricts its crystallization behavior, which results in that the overall crystallization process does not obey the Ozawa equation. Furthermore, the study of the crystalline morphology of PLLA-PEG at different cooling rates indicates that when the cooling rate is from low to high, the crystalline morphology undergoes a transformation from the ring-banded spherulites to the typical Maltese cross spherulites, which experiences the mixed crystalline morphologies of ring-banded and typical Maltese cross spherulites, and the spherulitic size becomes smaller.

溶胶-凝胶法制备纳米Pb(Zr_(0.52)Ti_(0.48))O_3

以醋酸铅 ,硝酸氧锆 ,钛酸四丁酯为原料用溶胶 -凝胶法制备了纳米 Pb( Zr0 .52 Ti0 .48) O3 ( PZT)。结果表明 ,随溶剂中乙二醇单甲醚与水的比例的增大 ,PZT粉体的晶化温度增高 ,晶粒的粒径尺寸也增大 ,当V( C3 H8O2 ) / V( H2 O) =4 .4 7时 ,不仅凝胶完成时间短 ,且可得到粒度分布集中、晶化温度低的 PZT粉体。用原子力显微镜测定 PZT的粒径为 6 0～ 70 nm,用 TG-DTA分析确定在 4 43℃即可发生晶化反应 ,在 5 0 0℃下结晶完善。通过对不同温度下热处理的粉体的红外光谱和 X射线衍射的分析 ,对溶胶 -凝胶法制备 PZT粉体形成钙钛矿结构的过程进行了研究。

Separation of zinc(II) from europium(III) by using hollow fiber membrane

Extraction and separation of Eu3+ and Zn2+ in sulfuric acid solution was investigated by hollow fiber membrane with cyanex 302 (bis (2,4,4-trimethylpentyl) monothiophosphinic acid) in counter-currently circulating operation. Reaction mechanism of membrane extraction and effect of extractant concentration and H+ concentration in aqueous phase on the mass transfer coefficient were discussed. It can be concluded that Zn2+ can be extracted completely from Eu3+ sulfate solution according to the kinetics competing difference. In one extractor process, extraction percentage of Zn2+ was not completely and Eu3+ was not extracted. Extraction percentage of Zn2+ reached 94.92%, but Eu3+ only reached 8.59% after 100 minutes extraction in two series connectors and that of Zn2+ and Eu3+ reached 99.9% and 6.53% respectively after 40 minutes extraction in three series connectors.

利用中空纤维膜器从铕中分离杂质锌

利用中空纤维膜器，采用逆流循环萃取法，用二（２，４，４－三甲基戊基）硫代膦酸（Ｃｙａｎｅｘ３０２）从硫酸溶液中萃取分离锌和铕。探讨了膜萃取的反应机制，考察了料液酸度、萃取剂浓度等因素对传质系数的影响，提出利用动力学竞争可以实现锌、铕混合组分的分离。研究了不同酸度、不同配比以及膜器串联的不同级数等条件对锌、铕混合物分离的影响。采用单级萃取时，只有锌被萃取，而铕不被萃取，且锌的萃取不完全；当采用膜器二级串联，经过 １００ｍｉｎ后锌的萃取率达到 ９４．９２％，而铕的萃取率仅为８．５９％；当采用膜器三级串联时，经过 ４０ｍｉｎ后，锌的萃取率达到 ９９．９％以上，而铕的萃取率仅为６．５３％。