同层排水技术的特点与分类

文章阐述了同层排水系统的优点、种类及有关设计要点,重点比较和介绍了同层排水的几种形式及其各自的利弊。     

建立长效机制推进上海市建筑节能

文章总结上海市建筑节能现状,提出推进上海市建筑节能工作的措施。     

POLYMER DIODES MADE OF ION IMPLANTED POLYACETYLENE FILMS

Polyacetylene films were doped with FeCl3 and implanted with 30 k'eV K+ ions. Physical changes to the films were examined by a series of measurements, which include the four-probe test, infrared ray absorption and 2 MeV He+ particle elastic recoil dettection and Rutherford backscattering. The chemical dopants (Fe+++ and Cl-) were redistributed after the implantation and the different species (K+. Fe+++ and Cl-ions) formed p - n junctions at the implantation depths. The implanted films exhibited desirable Ⅰ-Ⅴ characteristics, with current densities as high as 600 mA/cm- at 3V and back - to - forward ratio of current over 300. The polymer diodes kept their behavior for over 60 days. Discussions on the results were given in detail.     

Electromagnetic behavior of superconductors in a microwave field

Our research on the surface impedance of superconductors in microwave, millimeter, and submillimeter wave frequency ranges has revealed the nature of the interaction between microwave and superconductors. The complete solution to the Mattis-Bardeen (MB) quadruple [Phys. Rev. 111, 412 (1958)] and the analytical simplification of the MB formula to a double integral have been given. The theoretical calculations for metallic superconductors (Al and Sn) are in excellent agreement with the typical experimental data [Biondi and Garfunkel,Phys. Rev. 116, 853 (1959); S. Sridhar,J. Appl. Phys. 65, 159 (1988)]. Whereas for oxide superconductors a new microscopic model has been suggested because of its distinctive electromagnetic behavior compared to that of conventional superconductors, we think that the nonlinear effect caused by the strong anisotropy in superconductivity is one of the reasons why oxide superconductors give an unusual response.     

六轴数控滚齿加工综合误差数学建模

利用齐次坐标转换法，针对滚齿时刀具与工件切削点的误差建立了六轴滚齿机综合误差数学模型，为便于模型应用于实际直齿加工中，对模型作了进一步简化，并通过采样求出了简化误差数学模型。该模型适用于需要综合考虑各种误差影响，而又不便于测量这些误差的场合。     

道路沥青及SBS改性沥青的紫外老化研究

采用紫外辐射试验对道路沥青和SBS改性沥青进行加速老化试验研究.利用老化前后的软化点、针八度、延度和四组分变化。分析了道路沥青的紫外线老化机理。结果表明:随紫外线老化时间的延长,道路沥青和SBS改性沥青软化点呈上升趋势、针入度和延度呈降低变化趋势,其中又以延度变化最为明显。经紫外线老化后道路沥青和SBS改性沥青的四组分也有变化,其中沥青质略微上升、芳香分略微降低,而饱和分和胶质变化不大。     

Reconstruction of smooth distributions within unsmooth circumferences from limited views using filtered‐backprojection algorithm

This study demonstrates the feasibility of reconstruction of smooth distributions within unsmooth circumferences from limited views using the filtered‐backprojection algorithm with angular interpolation in Fourier domain, which leads to noniterative reconstruction of smooth distributions within skulls in diagnostic medicine. Two phantoms with a circular and an elliptic circumference are numerically tested. This speedy approach has great advantages in applications when swift reaction is necessary or when result of reconstruction is indispensably navigational to its following detection. © 2002 Wiley Periodicals, Inc. Int J Imaging Syst Technol 12, 93–96, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10015     

Discussion on the determination of sail residue in silk fibroin solution with a water quality testing pen北大核心CSCD

the salt residue is one of the quality indexes of silk fibroin products.The products with low salt residue are not only healthier for human body, hut also more stable in exterior qualities, such as color and smell.Instrumental analysis and chemical analysis are currently methods to accurately determine salt residues in silk fibroin products, but they still need to be supplemented by real-time and quick detection methods in practical production.This paper discusses the determination method with a water quality testing pen and investigates the response of the water quality pen to the changes in the concentration of a variety of solutions, and associates with application examples.The results show that the TDS measured by the water quality pen is highly linearly correlated with the changes in the concentrations of CaCU , NaCl, and fibroin-CaCU solutions.The principle and method of the TDS water quality testing pen have an application prospect in the field of real-time and rapid approximate evaluation of salt residue in silk fibroin solution. © 2021 China Silk Association. All rights reserved.     

小变形悬架衬套全刚度力学模型的建立与验证

鉴于衬套对悬架及整车性能影响较大,以扭力梁后悬架的橡胶-钢衬套为研究对象,先通过有限元分析结合响应面优化算法对相应Yeoh本构模型的多系数寻优,拟合出逼近试验曲线的沿x/y/z三向刚度仿真曲线,为优化后的衬套模型建立新的边界条件,求解拟合出绕x/y/z三向扭转刚度仿真曲线;进一步以扭力梁后悬架的极限扭转为工况,分别对含全6向刚度衬套力学模型和含刚柔耦合预紧衬套模型的扭力梁后悬架进行结构强度分析,两种分析结果均满足材料强度要求,最大应力和最大位移出现位置相同,各自相对误差分别是6.58%和1.27%,工程中属可接受范围。研究表明,在开展小变形范围内的悬架橡胶-钢衬套相关研究时,为达到减小建模工作量、缩短计算时间、不降低计算精度等目的,可以使用简单的全6向刚度衬套力学模型代替其他较复杂衬套模型。