Influence of salinity and moisture on the threshold shear velocity of saline sand in the Qarhan Desert,Qaidam Basin of China: A wind tunnel experiment

Determination of the threshold shear velocity is essential for predicting sand transport, dust release and desertification. In this study, a wind tunnel experiment was conducted to evaluate the influence of salinity and moisture on the threshold shear velocity of saline sand. Saline sand samples (mean particle size of 164.50-186.08 μm and the total silt, clay and salt content of 0.80%-8.25%) were collected from three saline sand dunes (one barchan dune and two linear dunes) in the Qarhan Desert, Qaidam Basin of China. Original saline sand samples were placed in two experimental trays for wet and dry processing to simulate deliquescence and desiccation, respectively. Surface moisture content ranging from 0.30% to 1.90% was generated by the steam method so that the saline sand can absorb water in a saturated water vapor environment. The motion of sand particles was determined by the observers with a solid laser. The laser sheet (0.80 cm thick), which was emitted by the solid laser, horizontally covered the sand surface and was bound to the sand. Results show that the cohesion of saline sand results from a combination of salt and water. The threshold shear velocity increases exponentially with the increase in crust thickness for the linear sand dunes. There is a positive linear correlation between the original moisture content and relative threshold shear velocity. The threshold shear velocity of dewatered sand is greater than that of wet sand with the same original moisture content. Our results will provide valuable information about the sand transport of highly saline soil in the desert.     

一种高质量天门冬基因组DNA提取方法

针对天门冬[Asparagus cochinchinensis(Lour.)Merr.]成熟叶片富含多糖、多酚、蛋白质及其他次生代谢物质的特点,采用改良CTAB法对其基因组总DNA进行提取,并对DNA进行质量检测。结果表明,改良CTAB法可从天门冬成熟叶片中获得纯度高、完整性好的总DNA,其OD260 nm/OD280 nm为1.86,OD260 nm/OD230 nm为2.36,浓度为390μg/mL,产率达11.7μg/g,多糖、多酚和RNA杂质被去除干净,无降解现象,说明该方法提取的天门冬基因组总DNA质量较高。     

山核桃天然群体家系种实和幼苗性状变异分析

基于岛石天然林山核桃自由授粉产生的44个单株果实与种子的表型及由种子实生繁殖1年生幼苗生长性状11个指标的数据,分别计算了各指标的特征值,并进行了方差分析,研究其自然变异.结果表明,果实和种子各表型变异程度不一,其中以果实质量的变异系数最大,为11.22％;其次是种子质量和出籽率,分别为8.64％和7.66％;种实各指标在采样单株间的差异均极显著.除果实质量与果形指数和种形指数之间无显著相关外,其余各指标两两间相关均极显著.1年生苗木苗高和地径变异系数分别达13.99％、10.28％,且各家系间差异极显著;苗高与地径的Pearson相关系数为0.552,相关性极显著.2个苗木生长指标与9个种实表型指标间相关性不显著.     

细分外推与模糊预测在近海水质非线性时序处理中的比较分析

近海水质非线性时间序列通常由于采集范围大、时间间隔长带有一定震荡性和模糊性,这使得对其进行分析与预测有一定的难度。本研究中以某近海水质指标磷酸盐(PO3-4-P)、硝酸盐(NO-3-N)、亚硝酸盐(NO-2-N)、铵盐(TNH+4-N)和硅酸盐(Si O2-3-Si)所形成的5种时间序列为例,采用逼近细分模式导出的细分外推法和多参考加权数据的模糊预测法对近海水质时序预测进行了比较分析,并通过图形与误差计算比较了两种方法的异同。结果表明:采用细分外推法预测序列在整体形状上能更好地逼近初始时序,而模糊预测法在整体逼近精度上占有优势。本研究中提出的预测比较方法可为同类问题的预测与模型选取提供参考依据。     

盐池湾保护区的药用植物资源

从盐池湾保护区药用植物资源的多样性,特、稀有药用植物资源,药用植物资源的性味特征,蒙医药药用植物资源等多方面论述了在盐池湾保护区药用植物资源的现状。     

鹿哈胶囊中总氮量测定方法研究

采用《中国药典》氮测定法测定鹿哈胶囊中总氮量,以总氮量作为制剂中的质量控制指标。鹿哈胶囊总氮量在24.98mg~29.89mg显良好的线性关系,平均回收率98.26%,RSD 1.06%。该方法适于鹿哈胶囊的总氮含量测定。     

Dahlin控制器的根轨迹的绘图方法

财产保险公司绝大部分业务来自于车险业务，因而车险业务的绩效关系到财险公司的经营业绩，甚至整个保险业的稳定和健康发展。从承保、理赔、续保及财务四个方面选取17个具体指标构建车险业务绩效评价指标体系进行有效性检验，计算某财险公司湖南分公司车险业务绩效水平指数，评价其车险业务经营状况。结果显示：该公司财务指标对车险业务影响的权重最大，综合车险指数呈上升趋势，表现出较好的经营状况。     

山西白羊草种质资源遗传多样性的 ISSR 分析简

 利用ＩＳＳＲ 分子标记技术对山西３３个白羊草种质资源进行遗传多样性分析。白羊草种质间遗传变异较稳定，１０条ＩＳＳＲ 引物共扩增出９９条带，多态性比率（Ｐ）为５２．２３％；通过ＰｏｐＧｅｎ３２软件计算出：等位基因数（Ｎａ）为１．５２５３±０．５０１９，有效等位基因数（Ｎｅ）为１．２９４１±０．３６６５，Ｎｅｉ’ｓ基因多样性（Ｈ）为０．１７２３±０．１９８３，Ｓｈａｎｎｏｎ信息指数（Ｉ）为０．２５９０±０．２８４１；通过ＮＴＳＹＳｐｃ１．２０ｃ软件计算出３３ 份材料间的遗传相似系数（ＧＳ）为０．８１８８～０．９８０１，遗传距离（ＧＤ）为０．０２００～０．１９８８。结果表明，３３份种质材料居群水平的遗传多样性较低，而自然条件下白羊草进行无融合生殖可能是导致白羊草居群遗传多样性较低的原因之一。     

Effect of Dietary Lactobacillus fermentum from Pig on Growth Performance,Nutrient Apparent Digestibility,Faecal Microflora Number and Serum Immune Indices in Weaned Piglets

This experiment was conducted to study the effects of Lactobacillus fermentum on growth performance, nutrient apparent digestibility, faecal microflora number and serum immune indices of weaned piglets.A total of 160 weaned piglets with an average age of (30±2) days and averge body weight of (7.85±0.68) kg were randomly distributed into 4 groups with 4 replicates per group and 10 piglets per replicate feeding basal diet, 0.1%, 0.2%, and 0.3% Lactobacillus fermentum supplementation diets, respectively.The experiment lasted for 35 d.The results showed that, compared with the control group, the average daily gain, the feed conversion ratio, the apparent digestibility of crude protein, calcium and total phosphorusin of Lactobacillus fermentum groups were all increased in varying degrees.The optimum supplemental level of Lactobacillus fermentum should be 0.2%, and at this level, the average daily gain was significantly increased by 8.70% (P<0.05), the F/G was decreased by 4.62% (P<0.05), the apparent digestibility of crude protein, calcium and total phosphorus were significantly increased (P<0.05), the number of faecal E.coli was significantly decreased (P<0.05), and the serum IgG was significantly increased by 8.39% (P<0.05).The results indicated that Lactobacillus fermentum supplementation could improve the immune function, growth performance, the apparent digestibility of crude protein, calcium and total phosphorus and reduce the number of faecal E.coli of weaned piglets.