GC-MS联用技术分析单叶细辛超临界CO2萃取物成分

分析了单叶细辛超临界流体萃取物的化学成分。采用超临界CO2萃取技术,对单叶细辛在萃取温度35℃、萃取压力30 MPa、萃取时间2 h条件下得到的萃取物组分进行GC-MS分析。共分离出64个组分,通过MS库检索并鉴定了其中60个组分。结果表明:双叶细辛超临界CO2萃取物的化学成分主要为α-亚麻酸、棕榈酸、亚麻酸甲酯、2,4,4-三甲基-3-(3-氧代丁基)-2-环己烯-1-酮等。     

基于半参数变系数部分线性模型的小麦抗倒伏性分析

应用统计的方法在小麦的抗倒伏指数与自身的各指标间建立了一个半参数变系数部分线性模型,对小麦的倒伏情况进行预测。结果表明:该方法可有效预测小麦的抗倒伏性,对提高小麦的产量有一定帮助。     

和声搜索的半监督聚类研究与应用

由于现有的聚类算法还存在一些问题,研究了如何用和声搜索算法快速寻找最优的聚类中心,对于和声搜索算法也进行了一些改进.为了获得最佳的类中心数,采用了半监督方式循环测试各种中心数情况下的聚类质量.考虑到各维特征属性对聚类效果影响不同,采用了维度加权的方法进行特征选择.所有这些措施都是为了达到一个更好的聚类效果.实验结果表明,该聚类算法性能优于其它同类算法.算法被应用于并行计算性能分析中,用于区分和识别并行机的各个处理器运行性能类别.     

特高压输电塔实时监测系统的数据传输方法研究

对特高压输电塔安全状态进行实时在线监测是保障国家电网安全的一个重要手段,而特高压输电塔处于的复杂强干扰、弱无线信号的环境对数据可靠传输提出了较高要求。以基于无线传输信道建立的远程数据传输系统为基础,在分析了特高压输电塔环境特性对无线信道的影响基础上,提出建立一种基于应答确认与自适应数据动态重传机制的数据传输方法,该方法能自动根据无线信道情况,采用"快速启动"、"线性增长"、"回归发送"的动态机制来实时调整数据包大小,从而在保证数据传输可靠性基础上实现数据的最大效率传输。该数据传输方法经过实验验证,相比传统直接发送数据方法具有很高的可靠性和抗干扰性。     

WiMAX下LDPC编译码器仿真实现的研究

WiMAX下的编码方式是当今通讯技术研究的热门。介绍一种最受关注的纠错编码:低密度奇偶校验码(Low Density Parity Check,LDPC),讨论LDPC码在WiMAX条件下的基本原理和编译码设计;提出运用Visual C++特点构建LDPC码仿真平台,研究仿真设计过程;分析不同实现方法下对LDPC码性能的影响,通过对仿真结果的分析和思考,说明了Visual C++语言应用于LDPC编译码仿真的可行性、实用性和扩展性。     

行人大腿冲击器的生物仿真度

针对汽车行人保护碰撞试验中大腿冲击器的生物力学特性问题,采用THUMS(total human model for safety)人体模型与大腿冲击器进行对比仿真分析.模拟THUMS-SUV行人交通事故,并对THUMS人体模型大腿所受冲击力和弯矩进行了输出.根据事故中行人大腿初始碰撞条件和行人大腿最低能量状态,分别建立两种工况的行人大腿冲击器碰撞模型并进行模拟,对比分析行人大腿冲击器和THUMS人体模型大腿的动态响应、最大瞬间冲击力和最大弯矩.仿真结果表明:相对THUMS人体模型而言,大腿冲击器的最大瞬间冲击力偏高而最大弯矩偏低,行人小腿和上身的运动和接触作用,会影响大腿部位的接触力和最大弯矩,因此大腿冲击器的生物仿真度有待提高.     

Innovative phase shifter for pulse tube operating below 10 K

Stirling type pulse tubes are classically based on the use of an inertance phase shifter to optimize their cooling power. The limitations of the phase shifting capabilities of these inertances have been pointed out in various studies. These limitations are particularly critical for low temperature operation, typically below about 50 K. An innovative phase shifter using an inertance tube filled with liquid, or fluid with high density or low viscosity, and separated by a sealed metallic diaphragm has been conceived and tested. This device has been characterized and validated on a dedicated test bench. Operation on a 50–80 K pulse tube cooler and on a low temperature (below 8 K) pulse tube cooler have been demonstrated and have validated the device in operation. These developments open the door for efficient and compact low temperature Stirling type pulse tube coolers. The possibility of long life operation has been experimentally verified and a design for space applications is proposed.     

Luminescence and energy transfer of color-tunable Lu_2MgAl_4SiO_(12):Eu~(2+),Ce~(3+),Mn~(2+) phosphors

Energy transfer among the co-doped activators is an efficient route to achieve color-tunable emission in inorganic phosphors.Herein,photoluminescence tuning from blue to cyan has been achieved in the Lu_2MgAl_4 SiO_(12);Eu~(2+),Ce~(3+)phosphors by varying the Ce~(3+) concentration with a fixed Eu~(2+)content.With the further introduction of a Mn~(2+)-Si4+couple into the host lattice,the emission color can be tuned to red through the energy transfer of Eu~(2+)and Mn~(2+).The luminescence properties and the energy transfer mechanism were studied in detail.The energy transfer from Eu~(2+)to Ce~(3+)is certified as a dipolequadrupole interaction with the energy transfer efficiency of 41.4% and Eu~(2+)to Mn~(2+)belongs to a dipole-dipole interaction with the energy transfer efficiency of 94.3%.The results imply that this singlephased Lu_2MgAl4 SiO_(12):Eu~(2+),Ce~(3+),Mn~(2+)phosphor has a potential prospect for application in near-UV chip pumped white light emitting diodes.     

基于LIN总线的微车控制系统设计

针对民用微车控制系统存在逻辑关系简单、布局紊乱、单点控制、车身线缆数量较多等技术问题进行分析研究。设计基于LIN总线的电子控制系统,可实现集中管理、分散控制,同时采用微处理器作为控制核心,实现复杂的逻辑功能;各测控模块都预留有部分接口,可实现功能拓展。介绍了系统节点总体布局、控制核心电路设计和相应软件实现。实践证明该系统可有效解决上述难题。     

Optimal control of wheel loader actuators in gravel applications

The paper is about finding the global optimum for a wheel loader work cycle in a gravel application. This includes simulating the gravel and extracting the trajectories for the main actuators; propulsion, lift and tilt, during the work cycle. The optimal control method is dynamic programming and the optimum is calculated with regard to fuel efficiency [ton/l] but can be weighted towards productivity [ton/h].The analytical optimal control results are compared to an extensive empirical measurement done on a wheel loader and shows around 15% higher fuel efficiency compared to the highest fuel efficiency measured among real operators.