冰岛刺参调节血脂及其作用机制

本实验研究了冰岛刺参(Cucumaria frondosa)对实验性高胆固醇血症大鼠脂质代谢的调节作用及其机制.采用灌胃高脂乳剂方法建立实验性高胆固醇血症大鼠模型,检测血清总胆固醇(total cholesterol,TC)、甘油三酯(triglyceride,TG)、低密度脂蛋白胆固醇(low-density lipoprotein cholesterol,LDL-C)、高密度脂蛋白胆固醇(high-density lipoprotein cholesterol,HDL-C)含量;肝脏TC、TG含量和肉毒碱棕榈酰转移酶-1(carnitine palmitoyl transterase-1,CPT-1)、过氧化物酶体β-氧化酶系(peroxisomal β-oxidation enzymes,POE)、磷脂酸磷酸酶(Phosphatidic acid phophyhydrolase,PAP)活力;粪便总脂质、TC和胆汁酸排出量.实验结果显示,冰岛刺参能显著降低高胆固醇血症大鼠血清TC(p＜0.05)、LDL-C(p＜0.05)含量及LDL-C/HDL-C(p＜0.05);显著降低肝脏TC(p＜0.01)、TG(p＜0.01)含量,提高CPT-1(p＜0.01)和POE(p＜0.05)活力;显著提高粪便总脂质(p＜0.01)、胆固醇(p＜0.01)和胆汁酸(p＜0.01)的排出量.冰岛刺参能有效调节高胆固醇血症大鼠的脂质代谢,其作用机制主要是促进脂质在体内的氧化和异化,同时抑制其在消化道内的吸收.     

演示实验在自由落体运动教学中的巧妙应用

自由落体运动是学生了解匀变速直线运动的规律后接触的新知识．自由下落的物体学生在生活中常见，学生的思维定势是：重的物体下落快，轻的物体下落慢．如何既打破学生的思维定势，又能让学生从理论上顺利学到新知识呢？笔者认为讲好这节课的关键是做好演示实验．通过演示实验，让学生循序渐进地了解自由落体运动的确定过程，达到学习目的．     

压控振荡器可靠性论述

详细剖析了一体化压控振荡器的可靠性及其控制技术,着重从理论和实践出发讨论如何提高一体化振荡器的可靠性.     

IBM－PC微型计算机热电偶全自动测试检定系统

本文介绍了一种热电偶测试检定新工艺─—微型计算机热电偶全自动检定系统。应用微电子技术与微计算机技术实现热电偶全自动检定测试，系统测试精度高、软件功能丰富，操作简便，易于普及推广。     

EXPRESSION OF N-ras GENE IN HUMAN PRIMARY HEPATOCARCINOMA

Poly(A)~+ RNA was isolated from 9 specimens of human primary hepatic carcinoma, 1 non-tumorous liver tissue adjacent to cancer and 1 normal liver tissue samples. The Oligo-dT cellulose-purified poly(A)~+ RNAs were subjected to formaldehyde agarose gel electrophoresis, Northern transfer and hybridization with various ancogene probes. Two RNA species, 5.6 kb and 2.2 kb wore identified by N-ras gone hybridization in 6 out of 9 mRNA samples from primary hepatic carcinoma specimen. N-ras specific mRNA was not detectable in mRNA samples from normal human liver and tumor surrounding cirrhotic tissue. No detectable hybridization of mRNA from hepatoma and normal liver with Ki-ras or Ha-ras was observed.As human N-ras gene has been identified in DNA of mouse transfeetants transformed with PHC DNA, it strongly suggests that N-ras gene might be responsible for the transforming activity of part of cases of human liver cancer.     

阳离子交换树脂分离电感耦合等离子体质谱法测定空气颗粒物中铂族元素

用Dowex AG50W-X8阳离子交换树脂分离空气颗粒物中Pt、Pd、Rh测定的干扰元素Cu、Ga、Hf、Pb、Rb、Sr、Y.模拟标准液实验确定出Dowex AG50W-X8阳离子交换树脂分离流程的最佳条件:上柱HCl浓度为0.8 mol/L,树脂柱床高为4 cm,洗脱速率为1 mL/min.铂族元素分析的国际标准物质BCR-723对照分析表明,Pt、Pd、Rh的测定值与标准值吻合,干扰元素Cu、Ga、Pb、Rb、Sr、Y的分离效率均大于94%,这表明所建立的Dowex AG50W-X8阳离子交换树脂分离流程是可靠的.     

一种ADC前端无源差分抗混叠滤波器设计

高速数据采集系统中,信号采样必须满足奈奎斯特采样定理,否则将产生频率混叠现象,导致无法从采样信号中提取出原始信号。为了消除混叠现象对数据采集系统的影响,设计了一种5阶巴特沃斯型无源差分抗混叠滤波器,使用LTspice仿真软件对滤波器进行仿真,仿真结果表明,所设计滤波器在通带内衰减特性平坦。硬件实测结果显示,系统的无杂散动态范围（SFDR）为84.32d B,所设计的抗混叠滤波器可以有效消除信号混叠现象,并能保持较好的系统动态性能。     

基于三维异构集成技术的X波段4通道收发模组

基于硅基微电子机械系统(MEMS)三维异构集成工艺,设计了一款适用于相控阵天线系统的三维堆叠4通道T/R模组。模组由3层功能芯片堆叠而成,3层功能芯片之间采用贯穿硅通孔(TSV)和球栅阵列实现电气互连;模组集成了6位数控移相、6位数控衰减、串转并、负压偏置和电源调制等功能,最终尺寸为12 mm×12 mm×3.8 mm。测试结果表明,在X波段内,模组的饱和发射输出功率为30 dBm,单通道发射增益可达27 dB,接收通道增益为23 dB,噪声系数小于1.65 dB。该模组性能优异,集成度高,适合批量生产。     

Source identification of individual P M2.5 particles in Shanghai air in the winter of 2007 with synchrotron X-ray fluorescence microprobe

In order to further understand the sources of PM2.5 in Shanghai air, the synchrotron X-ray fluores- cence microprobe at the BL-4A Beamline of Photon Factory of High Energy Accelerator Research Organization, Japan, was applied to analyze the individual PM2.5 particles collected from Shanghai air in the winter of 2007. Eight categories of emission sources were recognized in these individual particles. The source identification shows that most of the analyzed PM2.5 particles are derived from vehicle exhaust and metallurgical emissions. This suggests that the important emission sources of PM2.5 in Shanghai air would be vehicle exhaust and metallurgical activities.     

A Radio Frequency Field Guide Using Field Induced Adiabatic Potential

We study the behaviour of atoms in a field with both static magnetic field and radio frequency （rf） magnetic field. We calculate the adiabatic potential of atoms numerically beyond the usually rotating wave approximation, and it is pointed that there is a great difference between using these two methods. We find the preconditions when RWA is valid. In the extreme of static field almost parallel to rf field, we reach an analytic formula. Finally, we apply this method to 87 Rb and propose a guide based on an rf field on atom chip.