Preparation,Characteristics, and Formation Mechanism of Oyster Peptide-Zinc Nanoparticles

Oyster peptide–zinc nanoparticles(OPZNPs)(28–108 nm) were prepared in the presence of 0.5%–0.9% zinc sulfate at pH 6.0–11.0. The obtained nanoparticles exhibited uniform size distribution and spherical shapes. Nanoparticle characteristics, such as size, surface charge, and hydrophobicity, could be adjusted by controlling zinc sulfate concentration and environmental pH. Increasing pH value or decreasing zinc sulfate concentration tended to reduce nanoparticle size and increase nanoparticle surface charge and hydrophobicity. OPZNPs presented good stability at near-neutral pH and could be stored for at least 20 days at 4℃. The results of the peptide conformation study and nanoparticle dissociation test proved that zinc ions and carboxyl groups are the key factors that affect OPZNP formation. The intermolecular combinations of carboxyl groups via zinc bridging facilitated the aggregation of oyster peptides. Nanoparticle formation was accompanied by aggregate association and conformational changes. These changes included increments in β-sheets, especially intermolecular β-sheets, at the expense of α-helixes. Overall, this work provided a green alternative route for the synthesis of OPZNPs.     

建筑点云几何模型重建方法研究进展

从大规模机载点云中重建几何精确、拓扑正确、语义丰富且屋顶遵循LoD3规范的建筑几何模型是当前机载点云建筑建模的难点和重点。为此,根据建筑几何建模思想,将国内外相关建筑点云建模方法分为5类建模体系,并对每一类体系中的代表文献进行了深入的综述和剖析。在此基础之上,提出当前机载点云建模算法存在的一些共性问题,并给出可能的解决方案及几何建模发展的趋势和后续潜在的研究方向,为完善机载点云建筑重建理论,发展更智能的建模算法,构建更高质量的建筑模型库,提供一定程度的参考和借鉴。     

利用锋生函数对2008年年初昆明准静止锋生消过程的诊断分析

利用ERA-Interim 0.125°×0.125°高分辨率逐6小时再分析数据,选取昆明准静止锋2008年1~2月长时间维持过程诊断分析了锋生函数及其各分项在锋面生消过程中的作用与贡献,并结合2016年1月20~27日锋面增强西进过程和1979年1月14~20日锋面减弱东退过程进行了比较分析。结果表明:（1）非绝热加热项对锋面生消作用较小,但存在显著的日变化。在辐射作用下,非绝热加热项日间表现为锋消,夜间为锋生。（2）西移冷气团在被高原大地形抬升过程中存在局地地形迫使冷气团下沉的情况,并导致垂直运动倾斜项表现为锋生。由于地形固定不变,局地锋生形成次级锋生带。次级锋生带与昆明准静止锋的形成、维持和东西摆动有密切的联系。（3）辐合辐散项和水平形变项是锋生函数变化的主要贡献项,其中水平形变项中的切变变形作用以锋生为主,而伸缩变形项在纬向产生锋生,在经向产生锋消。     

Research on analytical method of multi-slip surfaces of landslide based on softening characteristics of geomaterialEI北大核心CSCD

Landslide often exhibits characteristics of multi-stage destruction in practical engineering. However, the most dangerous slip surface and corresponding minimum safety factor are only concerned in general computing and design, this often leaves security risk. Considering the softening characteristics of geomaterial, a theoretical framework of effective simulation and evaluation of landslide multi-stage destruction is established with FLAC(3D) and Matlab software platform. Taken landslide in low-rent housing area of Dangjiaba in Xunyang county as an example, the process of forming multi-slip surfaces is revealed by progressive evolution of plastic shear strain, plastic tensile strain and shear strain increment and so on. It is shown that time and space sequences are not necessarily corresponding sequence. The temporal sequences of multi-slip surfaces are first-class main slip surface, second-class main slip surface and sub-slip surface; the spatial sequence is first-class master slip surface, sub-slip surface and second-class main slip surface. The number of slip surfaces is equal to the number of tension cracks in collecting on-site. The entry location of first-class main slip surface is in excellent agreement with the tension crack in the frontal part of landslide, but the positions of second-class master slip surface and sub-slip surface have little error with the tension crack on-site. The distribution and magnitude of strength parameters in the slip surfaces gradually change with the development of slip surface from peak strength to residual strength, this is the root reason why the multi-slip surfaces of landslide can be simulated effectively. The evolution of vector sum safety factors according the temporospatial distribution of material parameters in the multi-slip surfaces is obtained. It turns out that there are three different sequences of safety factors in the process of forming the multi-slip surfaces of landslide. It illustrates the active and passive relationships among all slip surfaces in the formation process.     

皖南地区下寒武统荷塘组页岩矿物组成及脆度分析

为了研究皖南地区下寒武统荷塘组页岩的矿物组成和页岩气储集层物性,本文对采自荷塘组的页岩样品进行了X射线衍射分析和有机地球化学实验。结果表明,皖南地区荷塘组页岩有机碳含量较高(多为1.0%~10.0%),有机质类型为Ⅰ型,热演化程度处于过成熟阶段(Rom为4.2%~5.3%);荷塘组页岩矿物组成复杂,以石英、黏土矿物和碳酸盐矿物为主,平均含量分别为68.2%、24.5%和3.3%,部分样品中含有少量的长石、菱铁矿、黄铁矿和石膏。与北美地区页岩相比,皖南地区荷塘组页岩的脆性矿物含量较高(平均73.9%),脆性指数较大(平均71.7%),表明该区荷塘组富有机质页岩具有良好的脆度,有利于页岩气储集层的可压裂性。     

非晶硅面阵探测器数字透射成像试验探讨

通过对钢板试件的数字透射成像检测试验,分析并研究了非晶硅面阵探测器成像检测系统、透照参数、检测工艺与检测图像质量的关系,并给出了检测过程中应该注意的问题.具体试验表明:面阵探测器X射线数字成像系统在一定厚度范围内的像质计灵敏度优于同厚度的射线照相B级要求.     

An operational MODIS aerosol retrieval algorithm at high spatial resolution,and its application over a complex urban region

Aerosol retrieval algorithms for the MODerate Resolution Imaging Spectroradiometer (MODIS) have been developed to estimate aerosol and microphysical properties of the atmosphere, which help to address aerosol climatic issues at global scale. However, higher spatial resolution aerosol products for urban areas have not been well-researched mainly due to the difficulty of differentiating aerosols from bright surfaces in urban areas. Here, an aerosol retrieval algorithm using the MODIS 500-m resolution bands is described, to retrieve aerosol properties over Hong Kong and the Pearl River Delta region. The rationale of our technique is to first estimate the aerosol reflectances by decomposing the top-of-atmosphere reflectances from surface reflectances and Rayleigh path reflectances. For the determination of surface reflectances, a Minimum Reflectance Technique (MRT) is used, and MRT images are computed for different seasons. For conversion of aerosol reflectance to aerosol optical thickness (AOT), comprehensive Look Up Tables specific to the local region are constructed, which consider aerosol properties and sun-viewing geometry in the radiative transfer calculations. Four local aerosol types, namely coastal urban, polluted urban, dust, and heavy pollution, were derived using cluster analysis on 3 years of AERONET measurements in Hong Kong. The resulting 500 m AOT images were found to be highly correlated with ground measurements from the AERONET (r² = 0.767) and Microtops II sunphotometers (r² = 0.760) in Hong Kong. This study further demonstrates the application of the fine resolution AOT images for monitoring inter-urban and intra-urban aerosol distributions and the influence of trans-boundary flows. These applications include characterization of spatial patterns of AOT within the city, and detection of regional biomass burning sources.     

祁连山区主要河流径流演变及趋势预测分析

应用多种趋势检验方法对祁连山区主要河流年平均径流量演变进行分析,并用数学建模技术对未来10年的径流量变化趋势进行预测。旨在为甘肃水利"十二·五"规划涉及的河西地区水资源配置和可持续发展以及应对气候变化的适应能力提供决策依据和技术支撑。结果表明:祁连山区现状径流量自东向西总体呈"减少—增加—显著增加"演变;预计未来该区5年、10年径流量值自东向西总体呈"减少—增加—增加"变化。     

Geochronology and Geochemistry of the Radiolarian Cherts of the Mada’er Area, Southwestern Tianshan: Implications for Depositional Environment

In the southwestern Tianshan,the geologic ages of many strata and their depositional environments are still poorly constrained because of complex structures.The Mada'er area is located in the Kuokesaleling belt,Southwestern Tianshan.The cherts from the former Wupata'erkan Group contain abundant radiolarian fossils,including 10 species which are identified as late Devonian to early Carboniferous in age.Eleven chert samples have SiO_2 contents ranging from 88.80 wt%to 93.28 wt%, and 2.02 wt%to 3.72 wt%for ...     

新疆沙尔湖煤田中侏罗世植物化石

首次报道了新疆东部沙尔湖煤田中侏罗世17 属27 种植物大化石和35 属50 种孢粉化石。该植物群以蕨类、苏铁类及本内苏铁类、银杏类为主要组成成分,时代可能为中侏罗早期。其地质古生物特征表明,该植物群生长的古环境可能为温暖潮湿并具季节性变化的暖温带的湖沼地区。