Libpcap数据包捕获机制剖析与研究

本文基于Linux平台,深入研究了国外优秀的数据包捕获函数库Libpcap,及它的改进版本Libpcap-mmap的结构和原理。并根据实验的结果,对这两种结构捕获数据包的性能进行了比较。     

基于信道缩短的TH-PPM UWB稀疏信道盲估计算法

针对TH-PPM UWB系统,提出一种基于信道缩短的UWB稀疏信道盲估计算法.该算法通过对接收信号进行信道缩短,有效地克服了信道过长给估计精度带来的影响.同时利用UWB信道的稀疏簇特性,避免了无谓的零值抽头估计,改善了该算法的性能.仿真结果表明:当信道长度大于符号长度时,该算法可以获得较好的估计性能.     

高速逆流色谱法在天然香料单离中的应用

高速逆流色谱(HSCCC)是一种新型的液-液分配色谱分离技术.由于其具有无不可逆吸附等优点,已被广泛应用于各个领域.在简介HSCCC分离流程与策略的基础上,综述了HSCCC在天然香料分离纯化领域中的应用,并展望了HSCCC在该领域的研究及应用前景.     

Assessment of conversion efficiency of Cr4+ ions by aliovalent cation additives in Cr:YAG ceramic for edge cladding

0.25at.% Cr:YAG ceramics were successfully fabricated as the edge cladding of Yb:YAG transparent ceramic slabs through vacuum sintering of co‐precipitated powders, using oxide additives to introduce different cations. The effects of various cation additives (Si⁴⁺, Ca²⁺, and Si⁴⁺ + Ca²⁺) on the conversion efficiency of Cr⁴⁺ ions and optical characteristics of the Cr:YAG edge cladding were investigated. Measurements of the absorption spectra of the Cr:YAG ceramics without any additives revealed 2 absorption bands centered at 430 nm and 600 nm, which imparted the sample with a green color. The introduction of only Si⁴⁺‐bearing additive did not promote the transition of Cr ions from the 3+ to 4+ state. Theoretical analysis and experimentation revealed that the addition of CaO not only enhanced the microstructure and improved the transmittance of the Cr:YAG ceramic, but also introduced vacancies that assisted in the formation of Cr⁴⁺ ions. It was determined that CaO has the same effect on the conversion efficiency of Cr⁴⁺ ions whether it is added as a single additive or in combination with SiO₂. The underlying mechanisms by which these aliovalent cation additives influence the formation of Cr⁴⁺ ions and affect optical properties are discussed in detail. High quality composite ceramics with Yb:YAG transparent ceramic slabs and dark brown‐colored Cr⁴⁺: YAG ceramic edge cladding were achieved through the addition of 0.05 wt.% CaO to the edge cladding, with no interfacial effects between the 2 regions being observed.     

超声波辅助萃取天然植物香料研究进展

超声波辅助萃取技术近年已经在天然植物香料萃取方面得到越来越广泛的应用。对超声波（溶剂法）萃取、超声强化超临界CO2萃取和超声-微波协同萃取在天然植物香料提取方面的最新应用及研究进展进行了总结,同时对超声波辅助萃取天然植物香料前景进行了展望。     

Enhanced Hydrolysis of Cellulose to Reducing Sugars on Kaolinte Clay Activated by Mineral Acid

Catalysis Letters - Kaolinite, a natural, layered phyllosilicate, has been used as the solid catalyst for the hydrolysis of cellulose in our previous work. In the present study, kaolinite was...     

二辛酸丙二醇酯的非水相酶催化合成研究及应用

介绍了以辛酸和丙二醇为原料非水相酶催化合成二辛酸丙二醇酯的方法。研究确定的最优条件:选用BT-01脂肪酶为催化剂,辛酸与丙二醇摩尔比为2∶1,酶加量为丙二醇质量的1%,50℃下减压搅拌反应,反应7d结束,酯化率高达92.9%,反应物中含二辛酸丙二醇酯为85.6%。反应制得的纯品经质谱和红外光谱分析证实为二辛酸丙二醇酯。应用本合成法合成二己酸丙二醇酯、二丁酸丙二醇酯、二丙酸丙二醇酯和二乙酸丙二醇酯,相应的酯化率分别为84.3%、14.9%、11%、8.1%。     

Dy203掺杂(Ba,Sr)TiO3基电容器陶瓷的研究

采用单因素变量法研究了(Ba,Sr)TiO3基电容器陶瓷中掺杂稀土氧化物Dy2O3对材料介电性能的影响,得到了Dy2O3影响其性能的规律,即随着Dy2O3加入量的增加材料的介电常数开始增大随后减少,当W(Dy2O3)=0.5%时介电常数最大,而介质损耗逐渐减少.得到了介电常数为5245,介质损耗为0.0026,耐压为5.5kV/mm的高压低损耗陶瓷电容器瓷料.利用SEM分析了不同Dy2O3加入量样品的表面形貌.结果表明Dy2O3有强烈的偏析晶界、抑制晶粒生长和细晶、形成固溶体等来影响BST性能.这些结果为Dy2O3掺杂改性(Ba,Sr)TiO3基电容器陶瓷提供依据.     

企业信息化管理网络在宝钢股份HFW焊管厂的应用

介绍了宝山钢铁股份有限公司HFW焊管厂配置的信息化管理网络系统,重点对其ERP和MES系统的架构及主要模块的功能进行了描述.6年的运行实践表明,信息化管理网络系统的应用在企业快速响应市场,迅速准确地采集、传递生产信息,有效利用资源等方面起到了十分积极的作用,能够促进企业不断提高生产、经营、管理、决策的效率和水平.