三苯基膦与烯丙型氯代物的区域选择性反应

烯丙型氯代物与三苯基膦（Ｐｈ３Ｐ）在ＮａＩ存在下，发生区域选择性反应，存在γ取代的季磷盐，进一步研究表明，橙花醇苄醚的季磷盐在ＣＨ３Ｎａ／ＭｅＯＨ、ＤＭＦ体系中，可与醛发生ｉｔｔｉｎ反应生成反应的烯，而二丙叉丙酮的季磷盐在相同条件下不能与醛反应。     

神经网络和PID控制器在过程控制中的应用

运用ＰＩＤ控制器和神经网络相结合的方法，对一种非线性，变参数的受控对象的控制进行研究，仿真结果表明，控制效果比较令人满意。     

奇异摄动系统的概率神经网络滤波

将改进的概率神经网络（ＰＮＮ）用于奇异摄动系统的实时状态估计，注意针对系统快，变部分的滤波。仿真结果表明，ＰＮＮ滤波对于实时估计奇异摄动系统快变状态的适用性。     

Variation of δ13C in karst soil in Yaji Karst Experiment Site,Guilin

This study deals with δ13C variation in karst soil system of Yaji Karst Experiment Site, Guilin, a typical region of humid subtropical karst formations. Samples of near ground air, plant tissue, soil and water (soil solution and karst spring) were respectively collected on site in different seasons during 1996-1999. Considerable variation of δ13C values are not only found with different carbon pools of soil organic carbon, soil air CO2 and soil water HCO-3, but also with the soil depths and with different seasons during a year.The δ13C values of CO2 both of near ground air and soil air are lower in July than those in April by 1%-4‰ PDB. Our results indicate that the δ13C values of carbon in the water and air are essentially dependent on interface carbon interaction of air-plant--soil-rock--water governed by soil organic carbon and soil CO2 in the system.     

L''''Hospital法则的一个推广

本文将L＇Hospital法则推广为二元函数情形。     

WHEAT STRAW ALKALINE LIGNIN AND ITS DERIVATIVES AS RETENTION AID

1INTRODUCTIONLignin is one of the main three components in botany, and is one reproducible resource. It has three-dimensional network structure and more functional groups such as phenolic hydroxyl function group, alcoholic hydroxyl function group and methoxyl function group, so it has more reactivity and reaction active points [ 1, 2, 3, 4, 5, 6].Polyethylene oxide is applied in more fields as one kind of nonionic macromolecule. In papermaking industry, it is often used as dispersion agen…     

含氰基苯硫醚的选择性氧化

按照Mckillop的方法用四水合过硼酸钠(NaBO_3·4H_2O)氧化对硝基苯硫基乙腈的过程中同时发生了氰基的水解,得到混合物。经改变条件,采用分批加料法,控制反应温度(55—65℃),用四水合过硼酸钠氧化含氰基的对硝基苯硫醚,可以选择性的得到相应的砜和亚砜,而氰基不受影响。     

基于基站协作的空间应急通信系统及容量分析

根据中国地震带的分布特点,设计了一种适用于中国地震救灾的链状空间应急通信系统.该系统由若干个高空平台链状排列而成,每个平台搭载一个移动通信基站.针对基站、频谱等系统资源受限的现实约束,为了提高用户容量,提出了一种基于对称用户分组和平均功率分配的低复杂度基站协作方法.对该方法的用户容量性能的理论分析和仿真结果表明:与传统...