氧化锌晶须改性PP／POE共混体系的研究

研究了POE对PP力学性能的影响,氧化锌晶须表面处理及其对POE/PP共混体系性能的影响。结果表明:POE使PP冲击强度增加,拉伸强度下降。硅烷处理的氧化锌晶须改性PP/POE体系拉伸、缺口冲击强度都随晶须填充量的增加先升高后下降。氧化锌晶须用量在5份时,填充的PP/POE的拉伸强度达到最佳值;氧化锌晶须用量在10份时,冲击强度达到最佳。耐热性随晶须的填充量增加而先升高后降低然后再升高,在2.5份时出现极大值,在7.5份时出现极小值,氧化锌晶须含量进一步增大,其耐热性提高。     

氧化镁铁铝尖晶石耐火材料的制备

以铁铝尖晶石和镁砂为原料,采用烧结法制备了氧化镁铁铝尖晶石耐火材料.检测了各烧后试样的体积密度、显气孔率和常温耐压强度,利用应力应变法检测了烧后试样的弹性模量,利用X射线衍射(XRD)检测了烧后试样的物相组成,采用扫描电子显微镜(SEM)观察和分析了烧后试样的显微结构.研究结果表明: 1600 ℃时各试样体积密度最大,显气孔率最小,试样达到了烧结;镁砖中加入铁铝尖晶石会引起材料常温强度降低,铁铝尖晶石加入量在3%～4%为宜;铁铝尖晶石以颗粒形式加入的试样的弹性模量比以细粉形式加入的试样要大,所以铁铝尖晶石以颗粒形式加入的试样的抗热震性相对较好;热力学计算表明:当加热温度高于182 ℃时, MgO与FeAl_2O_4开始反应生成MgAl_2O_4;从显微结构照片也可以看出, MgO与FeAl_2O_4中的FeO发生互扩散,FeO扩散进镁砂颗粒中,MgO扩散进铁铝尖晶石内部,与Al_2O_3反应生成MgAl_2O_4,在镁砂颗粒周围形成MgAl_2O_4环,并伴有微裂纹产生.     

Separation of nickel catalyst by microfiltration

Ceramic membranes with pore size of 0.1 and 0.2 µm are used for the separation of nickel catalyst. Effect of trans‐membrane pressure (TMP), linear velocity, temperature and nickel content (solute) on flux and rejection has been investigated. The flux increased with increase in pore size of the membrane. The rejection characteristics were similar for 0.1 and 0.2 µm membranes. The nickel content and iodine value of the membrane‐filtered oil was comparable with that of conventional processes. Permeate flux increased with increase in temperature. Flux increased with increase in linear velocity and a marginal rise was observed above 2.09 m/s. The rejection characteristics were only slightly affected by higher linear velocity. The flux improved after back flushing. The average flux was higher with back flushing as compared to continuous (with out back flushing) filtration process. The results indicated that the secondary layer effect was more pronounced in microfiltration. The flux decreased with increase in solute concentration. The rejection characteristics were not affected by solute concentration. The rejection characteristic of the membranes remained unaltered after membranes were repeatedly cleaned with sodium hydroxide and HCl solutions, however, the flux was decreased marginally.     

简易包种法防治油菜跳甲的初报

[目的]采用简易包种法筛选有效防治油菜跳甲的化学药剂。[结果]杀虫单处理后平均保苗率在83%以上,而吡虫啉的防治效果最差,平均保苗率低于45%;三唑磷处理后出苗第9天,平均保苗率达85%;出苗第9天经吡虫啉.马拉硫磷的处理平均保苗率达88.79%;出苗第3天,氟虫腈.三唑磷混配剂处理后平均保苗率达89.64%;出苗第9天除氟虫腈.辛硫磷混配剂外,其余氟虫腈的混配剂处理后,平均保苗率在85%以上;杀虫单.辛硫磷混配剂处理后平均保苗率高于84%;出苗后第9天杀虫单.氟虫腈混配剂平均保苗率为93.43%。[结论]杀虫单和三唑磷单剂、吡虫啉.马拉硫磷混配剂、氟虫腈.三唑磷、氟虫腈.马拉硫磷、氟虫腈.杀虫单、杀虫单.辛硫磷的种衣剂对防治油菜跳甲在生产上有一定的应用价值。     

石墨/剑麻/聚丙烯电磁屏蔽材料加工性能的研究

采用密炼方式制备石墨包覆爆破剑麻填充聚丙烯(PP)电磁屏蔽材料,研究了该材料的加工性能,具体探讨了不同含量的石墨/剑麻的PP电磁屏蔽材料的力学性能、结晶性能以及毛细管流变性能的变化。结果表明,复合材料的拉伸强度随着填充物含量的增加而降低至23 MPa后基本保持不变;质量分数30%的石墨/剑麻填充物的弯曲性能最好,弯曲模量随着填充物含量的增大而增大;复合材料的结晶和熔融温度随着填充物含量的增大而升高;复合材料的流动性随着填充物含量的增加而变差。     

Fibre orientation distribution in turbulent fibre suspensions flowing through an axisymmetric contraction

The Reynolds averaged Navier–Stokes equation was solved numerically with the Reynolds stress model to get the mean fluid velocity and the turbulent kinetic energy in turbulent fibre suspensions flowing through an axisymmetric contraction. The fluctuating fluid velocity was represented as a Fourier series with random coefficients. Then the slender‐body theory was used to predict the fibre orientation distribution and orientation tensor. Some numerical results are compared with the experimental ones in the turbulent fibre suspensions flowing through a contraction with a rectangular cross‐section. The results show that the fibres with high aspect ratio tend to align its principal axis with the flow direction much easier. High contraction ratio makes the fibre alignment with the flow direction much easier. The contraction ratio has a strong effect on the fibre orientation distribution. Only a small part of the fibre is aligned with the flow direction in the inlet region, while most fibres are aligned with the flow direction when they approach to exit. The fibres are aligned with the flow direction rapidly in the inlet region, after that the fibre orientations change little in the most of the downstream region. The fibres with high aspect ratio are aligned with the flow direction faster when they enter the contraction. The randomising effect of the turbulence becomes significant in the downstream region because of the high turbulent intensity.     

环保型粘合剂XCB-2在全钢载重子午线轮胎胎体胶中的应用

研究环保型橡胶粘合剂XCB-2在全钢载重子午线轮胎胎体胶中的应用,并与间苯二酚和间苯二酚-甲醛树脂(以下简称间甲树脂)进行对比。结果表明:分别采用粘合剂XCB-2和间苯二酚-80等量替代间甲树脂,采用粘合剂XCB-2的胶料加工安全性最好,采用间甲树脂的胶料次之,采用间苯二酚-80的胶料最差;采用粘合剂XCB-2的胶料硫化速率与采用间甲树脂的胶料相当,均低于采用间苯二酚-80的胶料;采用粘合剂XCB-2的胶料物理性能和与钢丝帘线的粘合性能比采用间甲树脂的胶料略好;采用粘合剂XCB-2的胶料工艺性能良好,成本降低。     

Effect of silica reinforcement on natural rubber and butadiene rubber vulcanizates by a sol–gel reaction with tetraethoxysilane

The effect of silica reinforcement was studied for natural rubber (NR) and butadiene rubber (BR) vulcanizates by a sol–gel reaction with tetraethoxysilane at different temperatures. The formation of silica in the rubber vulcanizates was investigated analytically with Fourier transform infrared spectroscopy and energy-dispersive X-ray analysis. The variations of the mechanical and dynamic properties were measured in the NR and BR vulcanizates with silica filling. The hardness of the rubber vulcanizates increased with silica filling in the rubber matrix. The tensile strength and elongation at break decreased with silica filling in the NR vulcanizates. The moduli at 50, 100, and 300% elongation increased with silica filling in the rubber matrix. The storage modulus of silica-filled rubber vulcanizates became higher than that of pure rubber vulcanizates. The temperature dependence of the loss modulus also increased with silica filling. The temperature dependence of the loss tangent was maintained, regardless of silica filling in the BR vulcanizates. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

不同排列结构的纤维层对捕集PM2.5性能影响的数值模拟

基于离散颗粒模型(Discrete Phase Model,DPM)研究了三种纤维排列结构捕集颗粒物规律.模拟了不同排列结构的纤维层在拦截和惯性碰撞两种捕集机制下捕集颗粒物的性能,考察了颗粒物粒径、入口风速和纤维层填充率对平行排列、单层垂直排列和双层垂直排列纤维层捕集颗粒物性能的影响.结果表明,当颗粒物粒径为0.5～2...     

Effects of air temperature and humidity on particle deposition

Particle deposition in a fully developed turbulent duct flow was studied. The random walk model of Lagrangian approach was used to predict the trajectories of 3000 particles with a density of 900 kg/m³. The effects of thermophoretic force and air humidity were also considered. The results were compared with the previous studies with a particle size range of 0.01–50 μm and air flow velocity of 5 m/s. The profile of dimensionless deposition velocity with relaxation time presents a V-shaped curve and the results are in good agreement with the previous studies.The effects of air temperature and humidity on particle deposition with a particle size of 1 μm were also investigated. The results show that thermophoretic force accelerates particle deposition onto the duct walls with increasing temperature difference between air flow and the duct wall surface. Meanwhile, it was found that particle deposition velocity increases with air humidity.     

CTAB混合反胶团萃取工业脂肪酶

研究了CTAB与Tween、含氧有机物形成的混合反胶团对工业脂肪酶进行萃取分离的效果. 实验表明,CTAB-Tween85和CTAB-含氧有机物混合反胶团的萃取率高于单一CTAB反胶团;反萃时CTAB-含氧有机物混合反胶团的反萃率与单一CTAB反胶团的反萃率相似,CTAB-Tween60和Tween40混合反胶团的反萃效果优于单一CTAB反胶团. 通过测定反萃水相的酶活,发现CTAB-TRPO混合反胶团的效果最好,酶活回收率最高,可以达到70%.     

Adhesion Between Hydrated Aluminium and Ethylene Copolymers Containing Methoxy Silane Groups

The peel strength between ethylene copolymers and aluminium has been investigated. The polymers were ordinary LDPE, copolymer with butyl acrylate (EBA), copolymer with vinyltrimethoxysilane (EVS), and copolymer with both comonomers (EVSBA). The aluminium was modified by hydration in boiling water up to 120 s. The strength of melt-pressed laminates was tested with a T-peel test and the failure mechanism was evaluated by FTIR and SEM. The hydration leads to a porous pseudoboehmite with an increased content of Al-OH groups, which causes considerable increases in peel strength for all polymers, in particular for EVS and EVSBA. The mode of failure varied between adhesive and cohesive depending on the surfaces. The introduced porosity contributes with mechanical keying while the Al-OH groups enable polar interactions for EBA and the formation of interfacial covalent bonds for EVS and EVSBA.     

负直流电场对不同初始压力预混甲烷/空气火焰的影响

在定容燃烧弹中研究了常温（298 K）,初始压力P_initial为0.1～0.5 MPa,加载U=-5、-10 kV直流电场对甲烷/空气预混火焰燃烧特性的影响。结果表明：不同初始压力下,加载电压,火焰主要在水平方向发生拉伸变形,加载电压幅值越高,火焰变形越明显,初始压力越高,火焰不稳定性增加,火焰面褶皱增加。加载电压后,火焰传播速率明显提高,电压幅值增大,其提高程度逐渐明显,初始压力增大,其提高程度更加明显,电场对火焰的促进效果更加明显,λ=1.4,U=-10 kV,P_initial=0.1～0.5 MPa时,平均火焰传播速率分别提高35.67%～52.71%。相对于未加载电压,加载电压后,各初始压力下质量燃烧率均增大,随电压幅值升高而升高,且初始压力越大,质量燃烧率变化越明显;火焰的初始燃烧期和主燃烧期均缩短,初始压力越高,缩短程度也越明显,二者相比,初始燃烧期缩短的程度更为明显。     

具有两类信息基于轮询的实时介质访问方法研究

介绍一种新型轮询系统,工作站需要发送两类信息.其中实时信息的相邻生成时刻间距有最小值,而非实时信息则服从泊松分布.当被轮询时工作站采用混合策略服务这两类信息,实时信息采用穷尽式服务策略,非实时信息采用k-有限式服务策略.运用仿真方法,研究了服务参数对于轮询系统性能的影响.实时信息从产生到被服务的时间有确定的上界值,推导了实时信息的这种等待时间上界.     

白炭黑补强热塑性聚烯烃(POE)的性能研究

研究了不同品种和用量的白炭黑，偶联剂处理过的白炭黑以及白炭黑／炭黑并用补强POE的性能。结果表明，白炭黑对POE具有较好补强性能，不同牌号白炭黑的补强效果有一定的差异；用硅烷偶联剂VTPS处理的白炭黑补强POE的效果不明显；与同样粒径的炭黑相比，白炭黑补强POE的效果较好。     

不同电极加工的异形喷丝孔对纤维异形度的影响

采用铜电极及银电极加工的三叶形微孔喷丝板进行PET纺丝,探讨了不同电极加工的微孔伴随工艺条件的变化对纤维异形度的影响。结果表明:在相同的纺丝工艺条件下,银电极比铜电极加工出的微孔纺制的纤维异形度高。在不同工艺条件下,铜电极及银电极加工的微孔对纤维异形度的影响具有一致性,采用银电极加工微孔有利于提高异形纤维的异形度。     

含Y2O3玻璃的弹性模量

根据硬盘基板用材料的要求，借助Makishima-Mackenzie理论设计了MgO-Al2O3-SiO2-TiO2-Y2O3玻璃，获得具有较高弹性模量（120GPa)的玻璃，并研究了玻璃的弹性模量与其组成之间的关系，玻璃的弹性模量随组成的变化服从Makishima-Mackenzie理论，但玻璃弹性模量的理论计算值比测试值低约10GPa，这是因为Makishima-Mackenzie理论没有考虑玻璃内阳离子的具体配位状态，对MgO,Y2O3堆积密度因子的推导存在误差，利用Bocherulle公式改进氧化物堆积密度因子的计算后，Makishima-Mackenie理论数据与含Y2O3玻璃的实验结果能够很好地吻合。     

气相色谱法测定鸡肉中二硝甲酚的残留量

本文研究了鸡肉中二硝甲酚残留量的气相色谱测定方法。样品中二硝甲酚用丙酮提取，经重氮甲烷甲基化和氟罗里硅土柱净化一，采用BP21石英毛细管柱于气相色谱仪进行测定。本实验采用添加法测定回收率，添加水平为0.02-0.2mg/kg时，其平均回收率为84.6%-89.5%。本方法的最低检出限为测定0.02mg/kg。     

The Adhesion Properties of a Plasma Modified Thermoplastic Olefin Elastomer

The effects of nitrogen plasma on the adhesion of thermoplastic olefin elastomer (TPO) are studied with attenuated total reflection infrared spectroscopy (ATR), the lap shear test, and the contact angle measurement. The plasma is applied after the TPO is dip‐coated with acrylic acid (AA), mixed with benzophenone (BP), benzoyl peroxide, and 2,2‐azoisobutyronitrile initiators. ATR spectra confirm the presence of grafted AA on TPO, with the amount depending on the exposure time and the initiator used. The total surface energy and the polar component of the grafted TPO increase while the lap shear strength (LSS) decreases with exposure time, and all these also vary with the initiator. The plasma treatment and the grafted AA improve the LSS of the TPO. The greatest LSS is obtained from the specimen grafted with AA and BP. The nature of the reacted surface layer has a significant effect on the adhesion strength of the TPO.     

CO2与水蒸汽对焦炭溶损反应的影响

采用自制气-固相反应测定仪,于950~1200℃温度范围内研究了焦炭与CO2、水蒸汽的溶损反应. 结果表明,焦炭与水蒸汽反应的气化率约为与CO2反应的2~7倍,随温度升高,二者气化率差距缩小;焦炭与CO2或水蒸汽的反应过程受界面反应控制较明显,可用未反应收缩核模型描述,反应的活化能分别为165.48和82.25 kJ/mol;随温度升高,焦炭颗粒由外到内溶损量呈减少趋势,焦炭与水蒸汽反应比与CO2反应更多发生在颗粒表面;不同部位气孔生成方式不同,焦炭与CO2、水蒸汽反应后,边缘部位大于10 mm的气孔所占比例分别增加66.98%和94.01%,中心部位大于10 mm的气孔所占比例分别降低21.22%和3.30%.