圆柱形金属橡胶结构的静态力学性能

对圆柱形金属橡胶结构做静态实验,运用最小二乘法对实验数据进行拟合,得到金属橡胶材料本构方程的各系数,将由实验得到的各系数代入本构方程式中,从而得到理论拟合迟滞回线,将理论拟合迟滞回线与试验迟滞数据进行对比,发现理论拟合迟滞回线与试验迟滞数据吻合较好,同时运用ANSYS有限元软件对金属橡胶结构进行有限元建模、定义边界条件及施加载荷,最后进行应力应变分析,得到应力应变分布图,发现分析结果与实验结果吻合。     

偶联改性纳米HAP/HDPE挤出复合生物材料的力学性能和微观结构

通过化学共沉淀-水热合成法制备纳米级羟基磷灰石(HAP),再用自制模具制备出偶联剂改性纳米HAP/高密度聚乙烯(HDPE)挤出复合材料.通过SEM观察以及力学性能测试,研究了偶联剂改性纳米HAP/HDPE复合材料的微观结构和力学性能.结果表明: 添加硅烷偶联剂后,HAP/HDPE复合材料的力学性能获得提高,偶联剂含量为2%(质量分数)时拉伸强度最高.而当HAP含量为20%(质量分数)时,复合材料的拉伸强度和抗弯强度最高.添加了偶联剂,HAP微粒表面与HDPE有较好的亲和性,断裂过程中应力诱发的塑性变形增加,裸露的HAP颗粒明显减少.通过口模挤出可以使得聚乙烯分子链在应力作用下伸直取向,大量平行于长轴且紧密排列的微纤维形成.     

Relationship between mechanical properties and crystal structure in cocrystals and salt of paracetamol

Abstract

Objectives were to study mechanical properties of various solid forms of paracetamol and relate to their crystal structures. Paracetamol form I (PRA), its cocrystals with oxalic acid (PRA-OXA) and 4,4-bipyridine (PRA-BPY) and hydrochloride salt (PRA-HCL) were selected. Cocrystals and salt were scaled-up using rational crystallization methods. The resulting materials were subjected to different solid-state characterizations. The powders were sieved and 90–360?µm sieve fraction was considered. These powders were examined by scanning electron microscopy (SEM) and densities were determined. Tablets were made at applied pressures of 35–180?MPa under controlled conditions and the tablet height, diameter and hardness were measured. Tensile strength and porosity of the tablets were estimated using well known models. Crystal structures of these systems were visualized and slip planes were identified. Cocrystal and salt of PRA were physically pure. Sieved powders had comparable morphologies and particle size. The apparent and theoretical densities of powders were similar, but no clear trends were observed. The tensile strengths of these compacts were increased with increasing pressure whereas tabletability decreased in the order oxalic acid?>?PRA-HCL?≈?PRA-OXA?>?BPY?>?PRA-BPY. Tablet tensile strength decreases exponentially with increasing porosity with the exception of PRY-BPY and BPY. Slip plane prediction based on attachment energies may not be independently considered. However, it was possible to explain the improved mechanical properties of powders based on the crystal structure. Cocrystallization and salt formation have introduced structural features that are responsible for improved tableting properties of PRA.     

Analytical simulation of rib-web forging

The friction calibration curves were generalized using ALPID simulations of ring compression tests and were used to establish the friction factor associated in the workpiece-tool interface. ALPID simulations were carried out for different rib-web sections. The metal flow characteristics were closely watched and load requirements for these processes were established. The distribution of effective strain and strain rate and stress were established.     

两种含强供电基的三苯胺均二苯乙烯衍生物的合成及光电性能研究

设计合成了两种新型含强供电基团的三苯胺均二苯乙烯类化合物,并通过IR、MS、NMR进行了结构表征,用紫外吸收光谱、荧光发射光谱、循环伏安法(CV)等手段研究了它们的光电性能,分析了它们的电化学行为,计算出其电离势(P1)分别为5.41和5.54eV,带隙(Eg)分别为2.72和2.74eV,结果表明强供电子基团的引入大大增强了荧光量子效率和空穴的注入传输能力.     

Characteristics of carbon microspheres and study on its adsorption isotherms

In this paper a great deal of carbon microspheres with high purity, uniform diameter and good features were synthesized by CVD method, while acetylene and toluene were used as carbon sources. The obtained carbon microspheres were almost amorphous. The products were treated by microwave plasma and temperature vacuum heat treatments respectively, then the samples were analyzed and characterized by FESEM, XRD and HRTEM. The results showed that carbon microspheres were well graphitized while their features were undestroyed. Based on their adsorption isotherms of nitrogen, pore structures of carbon spheres were found to be changed greatly after graphitized treatments.     

有缺陷和无缺陷量子点内应变分布的比较与分析

阐述了量子点内能级结构与应变的关系,用ANSYS7．1计算了有缺陷和无缺陷两种情况下：InAs／GaAs量子点的应变分布,通过对计算结果的比较,讨论了两种情况下不同的应变分布对量子点电子结构影响的不同结果,指出有缺陷时量子点各能级的改变量都与无缺陷时不同,无缺陷时应变的作用只是使能级平行移动;有缺陷时,缺陷将使量子点内能级结构复杂化,有缺陷时发光波长和发光光谱都比无缺陷时复杂。     

Testing of explosive welding and welded joints. Wavy character of the process and joint quality

The basic defects occuring in explosive clad plates were properly systemized and the reasons of their formation were explained. Cases of cracks and delaminations in explosive clad plates were examined in this work. Various values of tensile stresses coming from loading and unloading waves were analysed, as they were the main reason of defects. The defects were connected with properties of welded materials in the joint area and beyond it. Some practical aspects of this process were shown as well.     

应用在食品行业中的冷封胶薄膜

概述了冷封胶薄膜的结构种类、制备工艺以及优点,接着陈述了冷封薄膜在软包装中的应用以及局限性,指出了实际生产中遇到的问题并对问题进行分析,提出改进方法.最后探讨了冷封薄膜未来的发展方向.     

Characterization of carbon nanotube-cdse hybrid nanomaterials

MWNT-CdSe hybrid nanomaterials were prepared with carboxylic acid-treated CdSe nanoparticles and amino-functionalized MWNTs. The hybridization of MWNT-CdSe nanomaterials was performed by the formation of covalent bond between MWNT and CdSe. Their covalent bond lengths were varied with changing the linking spacers. Amino-functionalized MWNTs were reacted with CdSe nanoparticles which were functionalized with carboxylic acid groups. Their detailed structures were characterized by FT-IR, XPS, and small angle X-ray scattering. Through small angle X-ray scattering experiments, it was found that the structures of CdSe nanoparticles were not regular, and their sizes were broadly distributed in solution. The longer amino-functionalized MWNTs were thermally decomposed at lower temperature. The photoluminescence (PL) of chemically-linked MWNT-CdSe hybrid nanomaterials were weaker than that of CdSe nanoparticles. In addition, their PL intensities more weakened on the MWNT-CdSe with the longer spacers.     

多壁碳纳米管对鲤鱼各组织SOD酶活性的影响

应用浸浴法研究多壁碳纳米管（MWCNTs）对鲤鱼（cyprinl Jscarpioio）腮、肝、肾和脑中超氧化物歧化酶（SOD）的影响,结果显示：低浓度（0．1,lmg·L^-1）处理组暴露后3d,腮和肝中的SOD活性显著高于对照组（p〈0．01）,肾和脑中SOD活性与对照组无显著差异（p〉0．05）。随着暴露时间延长,各组活性降低,至9d,肝和肾中SOD活性显著低于对照组（p〈0．05）,腮和脑中SOD活性与对照组无显著差异（p〉0．05）。高浓度（10mg·L^-1）处理组,整个暴露期间,肝中SOD的活性显著低于对照组（p〈0．01）,脑中SOD的活性与对照组无显著差异（p〉0．05）,腮和肾中SOD活性在暴露后3d,与对照组无显著差异（p〉0．05）,暴露后6d、9d,活性显著低于对照组（p〈0．05）。提示：MWCNTs对鲤鱼各组织中SOD酶活性的影响有时间和浓度依赖性。     

高岭土制备超细白炭黑的研究

以苏州高岭土为原料,经过煅烧、酸溶、过滤及干燥过程制备了超细白炭黑粉体,将制备的粉体用XRD和BET进行表征,并对其进行化学成分分析.XRD结果表明产物为无定型结构,化学分析结果表明该粉体具有较高纯度,BET分析结果证明该粉体为具有较高比表面积的介孔材料.     

基于LBL技术组装的渗透汽化聚电解质复合膜

综述了近年来采用层层静电吸附(LBL)技术组装的聚离子复合物渗透汽化膜的研究进展.对支撑体荷电处理方法进行了分类,讨论了聚离子派对、选择原则及自组装条件,并就LBL技术组装聚电解质复合物的一些发展动向提出了建议.     

透明聚氨酯树脂材料的热性能和力学性能

以4,4′-二环己基甲烷二异氰酸酯(H12MDI)、聚醚多元醇、交联扩链剂、催化剂及助剂合成了一些透明聚氨酯树脂材料。用FT—IR对其结构进行了表征。DSC、TGA测试其玻璃转化温度为95℃～110℃,质量损失5％和10％的热分解温度为265℃、280℃～286℃。SEM对其断口形貌分析表明,其断裂为脆性断裂或韧性断裂。力学性能测试其拉伸强度49MPa～56MPa,断裂伸长率11％～16％,抗弯强度106MPa～116MPa,弹性弯曲模量2006MPa～3089MPa,冲击强度19kJ／m^2～35kJ／m^2,邵氏硬度80D。透先率91％～93％。实验结果表明,透明聚氨酯树脂材料具有卓越的光学性能,优良的力学性能和中等的热稳定性能。     

Growth and study of some gel grown group II single crystals of iodate

Single crystals of calcium iodate and barium iodate were grown by simple gel technique by single diffusion method. The optimum conditions were established by varying various parameters such as pH of gel solution, gel concentration, gel setting time, concentration of the reactants etc. Crystals having different morphologies and habits were obtained. Prismatic, dendritic crystals of barium iodate and prismatic, needle shaped, hopper crystals of calcium iodate were obtained. Some of them were transparent, some transluscent, and few others were opaque. Both the crystals were studied using XRD, FT-IR, and thermal analysis. The crystals were doped by iron impurity. The effect of doping was studied using IR spectroscopy and thermal analysis.     

基于差影技术的乳腺微钙化点检测方法

目的 协助医生进行诊断，避免医生因大量阅片引起疲劳而造成误诊，提高乳腺癌早期诊断的效率和准确率。方法 先对乳腺钼靶X线照片数字化；再对数字化的乳腺影像归一化；然后从中选取感兴趣区域；最后利用差影技术检测出微钙化点并标示于影像中。结果 对于16幅（其中13幅含有微钙化）经过病理解剖确诊的乳腺钼靶片进行实验，利用本文方法共检测出14幅钙化图像。结论 该方法检出率高，微钙化点定位准确，值得进一步研究。     

Influence of Raw Material and Processes of Gelatins upon Photographic Characteristics of Dichromated Gelatin

Carbon tissues prepared using types of gelatin differing in raw material and process were sensitized by dichromate and their photographic characteristics were investigated. Sensitivity and gamma were dominantly determined by the higher molecular weight components of the gelatin, sharpness and resolving power were dominantly determined by viscosity; these properties were little affected by its origin.     

The prevalence of alcohol, cannabinoids, benzodiazepines and stimulants amongst injured drivers and their role in driver culpability: part i: the prevalence of drug use in drive the drug-positive group

Blood samples from 2,500 injured drivers were analysed for alcohol, cannabinnoids, benzodiazepines and stimulants. Overall, three-quarters of drivers tested negative for drugs. Alcohol was the most frequently detected drug. Cannabinoids were also detected at high rates, but the majority of drivers tested positive for THC-acid, the inactive metabolite of THC. Benzodiazepines and stimulants were detected at low rates, and detection rates for combinations of drugs were also low. Males were more likely to test positive for drugs, especially alcohol and THC, whereas females were more likely to test positive for benzodiazepines. A similar proportion of car drivers and motorcycle riders tested positive for drugs, although riders were more likely to test positive for THC. Single-vehicle crashes were particularly associated with alcohol for both car driver and riders, and for riders, multiple-vehicle crashes were particularly associated with THC.     

纳米晶稀土贮氢合金的研究

用双辊快淬工艺制备了纳米晶AB5型富镧稀土贮氢合金。对热处理后的合金进行X射线衍射和扫描电镜SEM分析，并测试合金的吸放氢等温平衡曲线PCT。结果表明，处理的合金晶粒尺寸〈50nm，该合金具有良好的吸放氢动力学性能。     

宽带钢力学性能试样机械加工的难点及解决办法

在制取力学性能试样的机械加工中常发现试样有不同程度的弯曲与扭转变形，严重影响试样加工精度和力学性能测试的准确性。对宽带试样变形的产生原因及其对试样机械加工质量的影响进行了分析，并提出了相应措施，取得了较好的效果，保证了加工质量，提高了加工速度。