镝—镧—邻氟苯甲酸—乙二胺体系荧光增敏效应

研究发现镝与邻氟苯甲酸（ｏ－ＦＢＡ）有较强的荧光反应，并观察到镧存在下的共发光现象．研究了该反应的荧光特点和影响因素，确定了反应和测定的最佳条件．镧的加入使原有的镝—邻氟苯甲酸—乙二胺体系的荧光强度增大了８５倍．在最佳条件下，浓度在５．０×１０－６～５．０×１０－５ｍｏｌ·Ｌ－１范围内与荧光强度成线性关系，检测限为１．０×１０－６ｍｏｌ·Ｌ－１．采用多点增量标准加入法测定了合成稀土样品中镝的含量．     

具有条件（S）的BCK－代数运算的分配性

给出具有条件（Ｓ）的ＢＣＫ－代数关于运算“”的一些性质，证明了此类ＢＣＫ－代数对运算“＊”和“”分别关于“∨”及“∧”是可分配的，同时若Ｘ是正关联的，则ｘｙ＝ｘ∨ｙ．     

Macroeconomic forecasting with mixed data sampling frequencies: Evidence from a small open economy

The aim of this study was to forecast the Singapore gross domestic product (GDP) growth rate by employing the mixed‐data sampling (MIDAS) approach using mixed and high‐frequency financial market data from Singapore, and to examine whether the high‐frequency financial variables could better predict the macroeconomic variables. We adopt different time‐aggregating methods to handle the high‐frequency data in order to match the sampling rate of lower‐frequency data in our regression models. Our results showed that MIDAS regression using high‐frequency stock return data produced a better forecast of GDP growth rate than the other models, and the best forecasting performance was achieved by using weekly stock returns. The forecasting result was further improved by performing intra‐period forecasting.     

健美运动对青少年体态的影响

本文以青少年健美训练的统计数据论述了健美运动对青少年体态的影响,并就健美训练的主要手段和注意事项做了介绍     

Comparison of the Hadley cells calculated from two reanalysis data sets

The Hadley cell (HC) is a vertical circulation cell with the largest scale, the strongest intensity, and the longest studying history in the atmosphere[1]. The common ascending leg of Northern and Southern Hemispheric HCs corresponds to the equatorial tro…     

Diversity of arbuscular mycorrhizal fungi associated with desert ephemerals growing under and beyond the canopies of Tamarisk shrubs

The arbuscular mycorrhizal （AM） fungal status of the four most common ephemeral plant species, Chorispora tenella （Pall.） DC., Ceratocephalus testiculatus （Crantz） Bess., Eremopyrum orientale （L.） Jaub et. Spash and Veronica campyIopoda Boiss growing in an area dominated by Tamarisk shrubs （Tamarix spp.） was investigated. Samples of the four ephemerals and their rhizosphere soils were collected from underneath and beyond the canopies of the Tamarisk shrubs. Plant mycorrhizal status and soil AM fungal spore densities and community structures were analyzed and compared under and beyond the shrub canopies. The mycorrhizal colonization rates of the ephemerals and spore densities in their corresponding rhizosphere soils were significantly lower under the shrub canopies than beyond. The number of AM fungal species under the shrubs （12） was also lower than beyond the canopies （19）. When soil properties in the rhizospheres of the four ephemerals were examined, available N and P and total P, organic matter content, total salt content and electrical conductivity （EC） were all higher under the canopies than beyond. In contrast, soil available K and pH showed no such trend. A total of 21 AM fungal species were isolated from rhizosphere soils of the four ephemerals. Five belonged to Acaulospora, one to Archaeospora, thirteen to Glomus and two to Paraglomus. We conclude that the canopies of Tamarix spp. exerted some influence on the AM status of the ephemerals and on the AM fungal communities and some of the properties of their rhizosphere soils.     

山水以形媚道——谈中国古代山水画与老子之道的生命美学

中国古代山水画，源于发达的农耕文明社会，成立于玄学鼎盛的魏晋时期，受道家美学思想熏染更深一些。文章结合老子之“道”的生命美学思想，阐明中国山水画独特的审美个性契合了老子生生不患的生命之“道”。即：水墨显现了“朴”的生命本色，空白处呈现了空灵的生命气韵，远的自觉体现了对“大”的生命境界的追求。     

修正Camassa-Holm方程的Cauchy问题

主要研究修正Camassa-Holm方程的Cauchy问题。首先提出了一个新的爆破结果,这一结果优化了早先获得的一些结果;然后证明了修正Camassa-Holm方程的Cauchy问题在解对初值不一致连续依赖意义下在空间H~3(R),s3/2中不适定。     

关于肿瘤细胞破坏并入侵正常组织或细胞质基质的数学模型的分析

固体肿瘤的生长分为两个阶段:未血管化阶段和血管化阶段。未血管化阶段的肿瘤处于扩散受到限制的休眠期,直径只有几毫米,而在血管化阶段肿瘤发生浸润和转移。主要研究了织肿瘤细胞破坏并入侵正常组织或细胞质基质的数学模型。这个模型包含了四个含有交叉扩散的抛物方程和一个退化的抛物方程。通过应用抛物型方程的Lp理论、Schauder估计、比较原理和Banach不动点定理,证明了这个模型整体解的存在唯一性。