任务驱动法在“组合逻辑电路设计与仿真”中的应用

采用任务驱动法进行教学,通过任务创建、分析、问题引领进行电路设计任务,通过用Multisim12.0创建测试电路并进行仿真,结合用数字实验箱动手连线验证,提高了学生学习兴趣,培养学生的创新意识。     

Electrochemical immunoassay for human chorionic gonadotrophin based on Pt hollow nanospheres and silver/titanium dioxide nanocomposite matrix

BACKGROUND: A new electrochemical immunosensor for human chorionic gonadotropin (HCG) assay was developed based on Pt hollow nanospheres and silver/titanium dioxide nanocomposites. Silver nanoparticles were initially doped into TiO₂ and chitosan (Cs) colloids to form silver/titanium dioxide nanocomposites (Ag? TiO₂? Cs), which had good redox electrochemical activity and excellent film‐forming ability. Then, the free amino groups of chitosan were used to attach Pt hollow nanospheres for immobilization of human chorionic gonadotropin antibody (anti‐HCG) to construct an immunosensor. RESULTS: Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) confirmed consecutive growth of the multilayer films, and transmission electron microscopy (TEM) was used to describe the microstructure of nanoparticles. Optimal response of the immunosensor was obtained at pH 6.5 and 25 °C with an incubation time of 40 min. The immunosensor exhibited a linear range from 0.5 to 250 mIU mL^?1 HCG with a detection limit of 0.26 mIU mL^?1 at three times background noise. The selectivity, stability and repeatability of the immunosensor were satisfactory. CONCLUSION: The strategy showed low‐cost, high sensitivity, broad linear range and fast analytical time. It is expected that the immobilized technique and the detection methodology could be further developed for other proteins. Copyright © 2010 Society of Chemical Industry     

人参皂甙20(S)-protopanaxadiol的氘、氚标记及其在A549细胞内的浓度

分别用钠硼氘、钠硼氚还原人参皂甙Rh1的活性形式20(S)-protopanaxadiol（aPPD）的氧化前体aPPD=O，制备氘、氚标记的aPPD。标记物经板层析（TLC）、质谱(MS)、核磁共振（NMR）分析鉴定，结果与标准品的测量数据一致；氚标记的aPPD放化纯度为98%，放射性比活度为7.64×1011Bq/g。将3H-aPPD作用于人肺腺癌A549细胞，检测不同时间细胞浆及细胞核中氚的活度，结果提示aPPD在A549细胞浆、核内均于24 h达到最高浓度，表明aPPD作为一个与甾体类激素结构相类似的药物，可以进入细胞甚至细胞核发挥药理作用     

Development of methods and instruments of the Russian service for determination of the Earth’s orbital parameters

The state and future outlook of research to determine the Earths orbital parameters, i.e., Universal Time and the coordinates of the pole, carried out by the State Time and Frequency Service and in calculations of the Earths orbital parameters are described.Translated from Izmeritelnaya Tekhnika, No. 1, pp. 24–27, January, 2005.     

鲁棒性概率优化在乘员约束系统设计中的应用

利用MADYMO软件建立了国内某微型车正面碰撞数学模型,并在对模型进行试验验证的基础上结合试验设计、响应面方法和鲁棒性概率优化设计对乘员侧约束系统进行优化,优化的参数主要有安全带刚度、安全带上挂点位置、限力器撕裂力和撕裂增加长度等。采用该方法引入鲁棒性概率优化设计后能减少和控制目标函数响应的波动,降低在设计点上的敏感性,提高产品的质量。结果表明,所采用的方法既实现了对设计目标的优化,又提高了设计变量的可靠性和目标函数的鲁棒性,对工程应用具有较大指导意义。     

铝基覆铜板导热系数测量中的几个关键问题分析

介绍了稳态双平板法测量铝基覆铜板导热系数的基本原理,采用有限元软件ANSYS12.0对传热板内的温度场进行了三维仿真,对传热板材质、外形尺寸的选取及侧面保温材料的必要性等关键问题进行了分析。     

虚拟环境下数控机床建模与仿真

基于虚拟样机原理，在Pro/ENGINEER下建立了机床的三维实体模型，并导入ADAMS12.0中进行动力学仿真。在虚拟环境下可观察机床整个机构的三维动态显示和运动过程.并可在样机试制前对设计中可能出现的问题做出精确的预测和改进，为机床的一次性试制成功提供了可靠的保证。     

不同土壤对化肥厂废水中铵的吸附特征

含铵化肥厂废水污灌有可能引起地下水污染。包气带土壤的吸附作用是阻滞其铵进入含水层的重要过程。选取某包气带不同深度4个典型土样,利用室内批模拟实验,以实验室配制硫酸铵溶液作对比,研究土壤对化肥厂废水中铵的吸附动力学及等温吸附特征。结果显示:土壤颗粒极易吸附铵,废水有机物等物质能延长吸附平衡时间,并影响土壤对铵的吸附能力——在低浓度铵溶液中表现为增加作用,在高浓度铵溶液中的表现为受土壤有机质含量影响;不同质地土壤对铵具有不同的吸附行为,总体上黏性土的吸附能力大于砂土;与Freundlich和Langmuir等温式相比,BET等温式能够与实验吸附数据更好拟合,验证了BET公式用于铵等温吸附特征研究的可行性,表明铵在土壤胶体颗粒中的吸附方式为多分子层吸附。     

组大鼠毛细血管内的镧盐颗粒穿过血脑屏障进入到脑组

生长发育期铅接触可使血脑屏障通透性增加,脑毛细血管内皮细胞紧密连接蛋白occludin表达降低可能是血脑屏障通透性改变的主要分子机制之一;铅接触的同时适量补充铁元素,可保护由慢性铅接触所造成的血脑屏障紧密连接的损伤.Effects of iron suppleme