太平洋鳕鱼脑中硫苷脂的分离纯化和分析

以太平洋鳕鱼为原料,从鳕鱼脑中分离硫苷脂,确立了提取及纯化的条件,并对硫苷脂的纯度和分子种进行分析。首先,采用氯仿/甲醇(2∶1,v/v)提取总脂。然后,依次采用氯仿/甲醇/水(7∶3∶0.3,v/v/v)洗脱硅胶柱层析,含0.2mol/L乙酸铵的氯仿/甲醇/水(30∶60∶8,v/v/v)洗脱DEAE Sephadex-A25离子交换柱层析,40%甲醇脱盐和100%甲醇洗脱反相C8柱层析,获得硫苷脂纯品。最后,利用500YMC Diol液相色谱柱(3.0mm×250mm,5μm)分离,以正己烷/异丙醇(70∶30,v/v),异丙醇/水/甲酸/氨水(100∶13∶1∶0.14,v/v/v/v)为流动相梯度洗脱,采用负电喷雾电离(ESI)和母离子扫描模式,用液相色谱-串联质谱(LC-MS/MS)法分析了鳕鱼脑硫苷脂的纯度和分子种组成,并比较了其与哺乳动物脑中硫苷脂分子种组成的异同。结果表明,本实验制得的鳕鱼脑硫苷脂纯度为90.74%,与哺乳动物类似,鳕鱼脑硫苷脂的长链碱基以鞘氨醇为主,主要分子种为d18∶1-C24∶1,但脂肪酸的羟基化程度略低,且含少量独特的分子种,如d18∶1-22∶1和d18∶2-25∶2。     

Optimal Forward-Scattering Angles of Atmospheric Aerosols in North China

The accurate understanding of atmospheric aerosol extinction coefficients is very important for at- mospheric science research. To achieve a fast and simple method for determining the parameters, the selection of optimal forward-scattering angles of atmospheric aerosols is required. In this paper, the authors introduce the detec- tion basis of forward-scattering of atmospheric aerosols, and the authors verify the sensitivity of the phase function to the real part of the complex refractive index. The au- thors use the Jaenicke urban aerosol model to determine that forward-scattering angles near 33° are suitable. However, the optimal forward-scattering angles in North China are between 37° and 40°. Numerical simulation shows that certain types of particle size distribution of newly generated particles and pollution have limited in- fluences on the selection of forward-scattering angles. But the ranges of these insensitive angles shift - 10 degrees for dust intrusion, and the relative deviations of the phase function are less than 5.0% within extra angles of 0° to 3°. This study can serve as a reference for the selection of optimal forward-scattering angles for visibility meters and Present Weather Identifiers （PWIs） in addition to the de- tection of forward-scattering optical properties.     

Assimilating the LAI Data to the VEGAS Model Using the Local Ensemble Transform Kalman Filter: An Observing System Simulation Experiment

Information on the spatial and temporal pat- terns of surface carbon flux is crucial to understanding of source/sink mechanisms and projection of future atmospheric CO2 concentrations and climate. This study presents the construction and implementation of a terrestrial carbon cycle data assimilation system based on a dynamic vegetation and terrestrial carbon model Vegetation-Global-Atmosphere-Soil （VEGAS） with an advanced assimilation algorithm, the local ensemble transform Kalman filter （LETKF, hereafter LETKF-VEGAS）. An observing system simulation experiment （OSSE） framework was designed to evaluate the reliability of this system, and numerical experiments conducted by the OSSE using leaf area index （LAI） observations suggest that the LETKF -VEGAS can improve the estimations of leaf carbon pool and LAI significantly, with reduced root mean square errors and increased correlation coefficients with true values, as compared to a control run without assimilation. Furthermore, the LETKF-VEGAS has the potential to provide more accurate estimations of the net primary productivity （NPP） and carbon flux to atmosphere （CFta）.     

Phylogenomic analysis of transcriptomic sequences of mitochondria and chloroplasts for marine red algae (Rhodophyta) in China

The chloroplast and mitochondrion of red algae （Phylum Rhodophyta） may have originated from different endosymbiosis. In this study, we carried out phylogenomic analysis to distinguish their evolutionary lin-eages by using red algal RNA-seq datasets of the 1 000 Plants （1KP） Project and publicly available complete genomes of mitochondria and chloroplasts of Rhodophyta. We have found that red algae were divided into three clades of orders, Florideophyceae, Bangiophyceae and Cyanidiophyceae. Taxonomy resolution for Class Florideophyceae showed that Order Gigartinales was close to Order Halymeniales, while Order Graci-lariales was in a clade of Order Ceramials. We confirmed Prionitis divaricata （Family Halymeniaceae） was closely related to the clade of Order Gracilariales, rather than to genus Grateloupia of Order Halymeniales as reported before. Furthermore, we found both mitochondrial and chloroplastic genes in Rhodophyta under negative selection （Ka/Ks〈1）, suggesting that red algae, as one primitive group of eukaryotic algae, might share joint evolutionary history with these two organelles for a long time, although we identified some dif-ferences in their phylogenetic trees. Our analysis provided the basic phylogenetic relationships of red algae, and demonstrated their potential ability to study endosymbiotic events.     

A Review of Aerosol Optical Properties and Radiative Effects

Atmospheric aerosols influence the earth's radiative balance directly through scattering and absorbing solar radiation, and indirectly through affecting cloud properties. An understanding of aerosol optical properties is fundamental to studies of aerosol effects on climate. Although many such studies have been undertaken, large uncertainties in describing aerosol optical characteristics remain, especially regarding the absorption properties of different aerosols. Aerosol radiative effects are considered as either positive or negative perturbations to the radiation balance, and they include direct, indirect (albedo effect and cloud lifetime effect), and semi-direct effects. The total direct effect of anthropogenic aerosols is negative (cooling), although some components may contribute a positive effect (warming). Both the albedo effect and cloud lifetime effect cool the atmosphere by increasing cloud optical depth and cloud cover, respectively. Absorbing aerosols, such as carbonaceous aerosols and dust, exert a positive forcing at the top of atmosphere and a negative forcing at the surface, and they can directly warm the atmosphere. Internally mixed black carbon aerosols produce a stronger warming effect than externally mixed black carbon particles do. The semi-direct effect of absorbing aerosols could amplify this warming effect. Based on observational (ground-and satellite-based) and simulation studies, this paper reviews current progress in research regarding the optical properties and radiative effects of aerosols and also discusses several important issues to be addressed in future studies.     

北斗三号MEO卫星非保守力建模

非保守力模型精度不高是制约BDS-3卫星定轨精度的主要因素之一。本文针对BDS-3 MEO卫星构建了地球辐射、天线辐射和箱体-两翼（BW）太阳光压模型,对典型的经验光压模型（ECOM1和ECOM2）进行补偿得到多个非保守力模型,收集全球观测网的数据进行定轨试验,通过轨道重叠互差和激光测距残差分析比较不同轨道模型的优劣。试验结果表明,经验光压模型是影响轨道精度的主要因素,在名义偏航模式下,ECOM2具有更好的表现,但ECOM1对卫星的姿态模式更不敏感。地球辐射和天线辐射会引起北斗卫星轨道径向约3 cm的系统性偏差,对二者建模后,几乎可以完全消除卫星C29和C30的激光残差系统偏差,但卫星C20和C21的系统偏差反而增大。此外,增加box-wing模型对于提高轨道精度也是有益的。     

地面沉降对高速铁路的影响分析

北京平原区快速发展的地面沉降对高速铁路的发展构成了威胁,地面沉降与过量开采地下水造成的水位下降关系密切,为此有针对性地开展基于高速铁路的地下水动态与地面沉降相关关系研究对于高铁安全运行意义重大,特别是对于制定高铁沿线地下水开采方案、地面沉降减缓措施和工程措施至关重要。基于其对高速铁路的影响模式,本文将地面沉降分为区域沉降和局部沉降两种类型。针对区域沉降,利用Logistic方程,使用天竺、望京及王四营分层地面沉降和地下水位数据,构建了不同层位地下水水位变化与地面沉降之间的相关关系模型,通过ABAQUS计算局部地区,对于6m高路堤和15m CFG桩处理深度的地基而言,当渗透系数k=2m／d,距离线路边缘25m处浅层地下水下降10m将产生约61—85mm的沉降。     

沂水县北躲庄铁矿地质特征

山东省沂水县北躲庄矿区处于汞丹山凸起之上,其西侧为马站苏村凹陷,东侧为莒县凹陷。区域地层分布较齐全,构造复杂,岩浆岩发育。该矿区地层简单,只出露新太古代泰山岩群柳杭组地层包体和新生代第四纪松散堆积物;构造有韧性剪切带和脆性断裂构造2种;岩浆岩发育,主要分布有古元古代条花峪单元、松山单元、三官寨单元。铁矿体赋存于泰山岩群柳杭组的顶部,共圈定了7个矿体,矿体呈层状产出,倾向110＆#176;～120＆#176;,倾角47＆#176;～82＆#176;。TFe 品位29％～37％。其矿体成因为沉积变质型铁矿。     

青藏高原伦坡拉盆地沉积岩中烷烃氢同位素与藿烷甾烷类成熟度指标的关系

沉积岩中烷烃的氢同位素有潜在的古降水同位素意义,但是成岩作用有可能改变原始同位素信息,从而难以用于恢复古降水同位素。然而,判断烷烃氢同位素值（δD）是否受到了成岩改造作用在学术界尚无统一标准。本文以青藏高原中部伦坡拉盆地渐新世末期到中新世早期的沉积岩为研究对象,对样品中正构烷烃和植烷（Ph）δD值以及藿烷、甾烷类的成熟度指标进行了测定。Ph与nC18正构烷烃的δD值分别为–105‰-–139‰和–267‰-–324‰,两者间平均相差–170‰,暗示正构烷烃原始δD值基本处于未改变的状态。藿烷、甾烷类的成熟度指标显示样品在未成熟到低成熟范围内有较大变化,但各成熟度指标与 Ph、nC18正构烷烃的δD值之间的相关关系较弱,表明这些成熟度指标并不能很好地反映烷烃δD值是否遭受了改变。     

安徽巢湖北部地区早石炭世碎屑锆石年代及其沉积意义分析

安徽巢湖北部地区石炭系出露完整,层序清楚,沉积类型多样,是下扬子地区研究石炭系的重要地区之一。本研究在分析石炭系剖面的基础上,结合U-Pb碎屑锆石年代学分析,探讨了巢湖北部地区早石炭世物源特征。本研究共对两组岩石样品进行了LA-ICP-MS U-Pb锆石年代学分析,第一组样品为采集于高骊山组中段的砂岩,第二组样品为采集于和州组顶部的砂屑生屑灰岩。高骊山组样品锆石最晚年龄为404.4±10.2Ma,最早年龄为3194.1±40.7Ma,获得了两个峰值年龄435±6Ma与846±14Ma。和州组样品锆石最晚年龄为410±10.8Ma,最早年龄为2780±46.0Ma,获得了两个峰值年龄448±20Ma与849±12Ma。早石炭世沉积特征及年龄数据表明,巢湖北部地区早石炭世的陆源碎屑沉积主要来源于扬子海周围晋宁期及加里东期形成的古陆,部分沉积物可能来自其他古陆。