记及压应力的内聚力单元及其厚度对复合材料分层损伤预测的影响

内聚力单元可以同时预测分层的起始和扩展,但单元尺寸对计算结果影响较大,而且无法模拟压应力导致的界面失效。首先,建立不同内聚力单元计算厚度的双悬臂梁模型、端边加载模型和冲击动力学模型,模拟分层损伤演化过程,研究内聚力单元厚度对载荷-位移曲线和界面损伤面积的影响;然后,通过子程序自定义内聚力单元的本构关系,考虑压缩应力引起的复合材料层间界面失效;最后,分析考虑压应力引起的界面层失效对复合材料冲击响应的影响。计算结果表明:内聚力单元厚度对界面层的损伤面积影响明显;相同的载荷条件下,内聚力单元厚度越大,界面损伤面积越小;考虑压缩应力引起的界面层失效,界面损伤面积较大且界面失效包含压缩和剪切两种失效模式。     

基于拉伸载荷的碳纤维/环氧树脂层合板疲劳断裂机理

为研究拉伸载荷下碳纤维/环氧树脂层合板的疲劳性能，开展了4种应力水平下的T300/6511碳纤维平纹织物层合板的拉-拉疲劳实验，得到了不同应力水平下层合板的疲劳寿命。采用超声波C扫和扫描电子显微镜（SEM）观察断口形貌及内部损伤，讨论复合材料疲劳损伤发展积累过程和断裂机理。通过复合材料疲劳有限元分析模型，模拟了复合材料织物层合板疲劳损伤积累和失效过程，绘制了S-lg N曲线，分析发现模型预测的疲劳寿命及失效模式与实验结果吻合良好。疲劳加载时，层合板两侧自由边的表面首先出现基体开裂和分层损伤，随后诱发基体与纤维间界面破坏，损伤加剧，并迅速向内侧扩展；最后大量纤维和基体断裂，损伤贯穿整个截面，导致疲劳断裂。     

连续碳纤维增韧SiC复合材料的制备与性能研究

利用ＬＰＣＶＩ技术制备了三维连续纤维增韧的碳化硅基复合材料,研究了复合材料致密度、界面相厚度以及纤维类型对碳化硅基复合材料性能的影响。研究表明：（１）随复合材料致密度的提高,由于基体和纤维之间力的传递效果变地,复合材料性能提高。（２）界面相厚度对复合材料性能的影响,可从其对界面结合强度、脱粘面上滑移阻力、界面相制备过程碳纤维的损伤程度以及界面相在基体沉积过程中对纤维的保护作用４个方面进行解释,界面     

三维正交机织复合材料弹道侵彻有限元模拟

测试复合材料弹道侵彻性质,得到复合材料弹道侵彻过程中子弹的入射速度和剩余速度及冲击破坏形态。基于复合材料的真实细观结构,建立细观结构模型,运用商用有限元软件ABAQUS/Explicit计算复合材料弹道侵彻破坏过程。研究发现三维正交复合材料不同破坏机制:三维正交机织复合材料不产生冲击分层,纤维断裂和基体开裂是主要吸能模式,复合材料冲击破坏是最主要的破坏模式。     

三维机织弯交复合材料细观结构研究及弹性性能分析

本文对三维机织弯交复合材料的细观几何结构进行了深入的研究，采用了椭圆形纤维束截面假设，详细研究经纱纤维束在织物表面与内部的不同。建立了一种新的三维机织弯交复合材料力学分析模型，并在此模型的基础上对其弹性常数进行了预测，讨论了结构参数和几何参数对三维机织弯交复合材料弹性性能的影响。通过实验值和理论预测值的对比，表明了分析方法的正确性。     

多尺度碳/碳复合材料力学性能研究

碳/碳(C/C)复合材料在服役过程中基体热解碳(PyC)强度低、脆性大,导致基体开裂、界面层脱黏等结构失效现象频发,严重限制其在特种环境中的应用。提出利用化学气相渗透法构建碳纤维与基体间的低织构热解碳界面层,采用电泳共沉积法掺杂碳纳米管(CNTs)、碳化硅纳米线(SiCnws)于碳纤维表面,构建纳米纤维-碳纤维多尺度预制体,实现多尺度C/C复合材料的制备和改性。研究发现,CNTs&SiCnws掺杂能促进C/C复合材料的弯曲性能、层间剪切性能和面内压缩性能的改善。弯曲、层间剪切、面内压缩强度随CNTs&SiCnws含量的增加均表现为“先升高后降低”的规律,CNTs&SiCnws可诱导细化PyC结构,避免基体微观缺陷的产生,提高纤维与基体的界面结合力,达到协同增强多尺度C/C复合材料的效果。     

增强橡胶界面层对材料力学性能影响的RVE计算

炭黑粒子与橡胶间相互作用的界面层对弹性体复合材料力学性能有重要影响。通过建立包含炭黑、橡胶基体及其界面层在内的三维RVE模型,借助有限元计算,研究了不同界面层厚度、界面层与基质不同模量比情况下弹性体复合材料的力学性能。研究发现,在一定范围内,界面层厚度及界面层模量与基质模量比值的变化都对复合材料体系的应力和模量有影响,计算条件下各组分承受应力由大到小的顺序为:颗粒内部应力界面层应力基体应力。     

X射线CT在C/SiC复合材料微观结构和损伤表征中的应用

本文采用X射线CT和三维数字图像处理与分析方法对C/SiC复合材料内部的微细观结构、损伤及其动态演化过程进行了表征,展示了X射线CT在认识C/SiC复合材料微细观结构和损伤机理等方面的优势,它不仅可以定性地在三维空间上揭示C/SiC复合材料内部碳纤维束、SiC基体和孔洞的三维形貌及其连通性,还可以定量地对每个个体的体积、表面积、厚度场等关键三维几何参数进行测量,获得孔洞、纤维束和SiC基体沿铺层厚度方向的变化规律;在不对试样进行破坏的情况下开展失效分析,在准确确定最终断裂位置的同时,对试样内部产生的微裂纹以及高温下发生的氧化行为进行表征。通过开展基于X射线CT原位观测的力学试验,可以对C/SiC复合材料试验件内部的损伤演化过程进行准确表征,为揭示其损伤和失效机理提供更加直接可靠的依据。     

基于ACP的碳纤维复合材料气瓶渐进损伤与爆破压力预测

碳纤维复合材料气瓶失效与爆破压力预测技术呈现出越来越多样化的趋势。基于ANSYS ACP建立了T800碳纤维复合材料气瓶理论模型,采用Camanho P P提出的刚度退化方案,对2.4L复合材料气瓶进行了渐进失效和爆破压力的预测,详细阐述了模型的构建和结构损伤,重点分析了含基体开裂、纤维断裂和内胆破裂缺陷下不同缠绕层的气瓶应力分布和损伤过程。最后通过水压爆破试验得到实验结果,该结果与理论值吻合较好。     

基于渐进损伤数值模拟的复合材料气瓶爆破压强优化

本文针对金属内衬复合材料气瓶进行渐进损伤的数值模拟并根据不同铺层方案气瓶的爆破结果进行优化选择。在ABAQUS软件中建立了气瓶模型,选用Hashin失效准则和Tan退化模型提出了渐进损伤理论,通过编写USDFLD子程序实现对复合材料模型渐进损伤的预测过程,并使用NOL环验证了损伤理论的准确性;对不同铺层方式的气瓶分别进行爆破结果的预测和渐进损伤分析。NOL环拉伸破坏结果表明,模拟得到的破坏应力与实际值的误差为1.9%,证明了渐进损伤理论用于环形缠绕模型是可行的。气瓶的爆破预测结果表明,预测的压力和失效位置与真实试验结果很接近。不同铺层的气瓶的爆破结果比较表明,铺层角度和数量对气瓶爆破压力及位置有较大影响。气瓶的渐进损伤分析结果表明,复合材料气瓶的损伤是一个从基体开裂逐渐过渡到分层缺陷,最终导致纤维断裂和气瓶爆破的过程。     

Inhibitory action of emulsified sulfoquinovosyl acylglycerol on mammalian DNA polymerases

We reported previously that sulfoquinovosyl diacylglycerol and sulfoquinovosyl monoacylglycerol (SQDG/SQMG) are potent inhibitors of mammalian DNA polymerases and DNA topoisomerase II, and can be potent immunosuppressive agents and anticancer chemotherapy agents [Matsumoto, Y., Sahara, H., Fujita T., Shimozawa, K., Takenouchi, M., Torigoe, T., Hanashima, S., Yamazaki, T., Takahashi, S., Sugawara, F., et al., An Immunosuppressive Effect by Synthetic Sulfonolipids Deduced from Sulfonoquinovosyl Diacylglycerols of Sea Urchin, Transplantation 74, 261-267 (2002); Sahara, H., Hanashima, S., Yamazaki, T., Takahashi, S., Sugawara, F., Ohtani, S., Ishikawa, M., Mizushina, Y., Ohta, K., Shimozawa, K., et al., Anti-tumor Effect of Chemically Synthesized Sulfolipids Based on Sea Urchin's Natural Sulfonoquinovosylmonoacylglycerols, Jpn. J. Cancer Res. 93, 85-92 (2002)]. In those experiments, the in vivo effectiveness greatly depended on the degree of water solubility of SQDG/SQMG. In the present work, we studied the emulsification of SQDG/SQMG in terms of their use in in vivo experiments. Lipid emulsions containing SQDG/SQMG (oil-in-water emulsions) in which the particle size was smaller than 100 nm were designed and synthesized, and then the biochemical modes of emulsified SQDG/SQMG were studied in comparison with those of SQDG/SQMG solubilized by DMSO. Emulsified SQDG/SQMG are also selective mammalian DNA polymerase inhibitors and potent antineoplastic agents but do not inhibit the DNA topoisomerase II activity. The growth inhibition effect of emulsified SQMG to NUGC-3 cancer cells was twofold stronger than DMSO-soluble SQMG (69 and 151 microM, respectively). From these results, the properties of lipid emulsions containing SQDG/SQMG and their possible use in in vivo experiments including clinical use are discussed.     

七种亚硝化反硝化聚磷菌的生长特性研究

亚硝化反硝化聚磷菌(NDPAOs)以亚硝酸盐为电子受体,具有同时脱氮除磷的特点,能够最大程度地减少碳源和氧气需求,因此可以大大减少能耗,节约成本。试验研究了7种NDPAOs——肠杆菌属(Ent.)、葡萄球菌属(Sta.)、副球菌属(Par.)、泛菌属(Pan.)、克雷伯氏菌属(Kle.)、芽孢杆菌属(Bac.)和莫拉氏菌属(Mor.)的释磷特性,并以纯培养的方式研究了它们的生长特性。结果表明,缺氧反应20 h后,Sta.、Bac.、Par.、Kle.、Pan.、Ent.和Mor.的单位细胞吸磷量分别为1.98×10-11、1.64×10-11、1.43×10-11、1.13×10-11、9.59×10-12、7.72×10-12和6.28×10-12mg/cfu。Ent.、Kle.、Bac.、Pan.、Par.、Sta.和Mor.的缓慢期几乎都处于0～6 h之间,对数期分别为6～144、6～72、6～96、6～52、6～31、6～96和6～72 h。Par.、Sta.、Pan.和Mor.的对数期的生长速率较Ent.、Bac.和Kle.的小。不同菌属的亚硝化反硝化聚磷菌的生长特性也不完全相同,特别是对数期的生长速率以及维持的时间相差较大。     

Comparison of discrete elemental modelling to experimental data regarding mixing of solids in the transverse direction of a rotating kiln

Finnie et al. [Finnie, G.J., Kruyt, N.P., Ye M., Zeilstra, C., Kuipers, J.A.M., 2005. Longitudinal and transverse mixing in rotary kilns: a discrete element method approach. Chemical Engineering Science 60, 4083-4091] developed a discrete elemental model to simulate the mixing of solids in a rotary kiln. It is interesting to analyse and compare their results to those obtained through experimental observations such as those by Henein et al. [Henein, H., Brimacombe, J.K., Watkinson, A.P., 1983. Experimental study of transverse bed motion in rotary kilns. Metallurgical Transactions B 14B, 191-205] Van Puyvelde et al. [Van Puyvelde, D.R., Young, B.R., Wilson, M.A., Schmitd, S.J., 1999. Experimental determination of transverse mixing kinetics in a rolling drum by image analysis. Powder Technology 106, 183-191; 2000. Modelling transverse mixing in a rolling drum. Canadian Journal of Chemical Engineering 78, 635-642] and Mellmann [Mellmam, J., 2001. The transverse motion of solids in rotating cylinders—forms of motion and transition behavior. Powder Technology 118, 251-270].     

Modelling mass transport in solid oxide fuel cell anodes: a case for a multidimensional dusty gas-based model

In this work the mass transport phenomena taking place in the fuel channel and the porous electrode of the anode of planar solid oxide fuel cells (SOFCs) are discussed. A comprehensive review of SOFC mass transport models in the literature is given and a new multidimensional, multicomponent, isothermal, dynamic model of the mass transport phenomena taking place in the fuel channel and the porous electrode of the anode of planar SOFCs is presented. The model can be used to predict species composition profiles and is based on the dusty-gas model (DGM) [Mason, E.A., Malinauskas, A.P., 1983. Gas Transport in Porous Media: The Dusty-Gas Model: Elsevier; Jackson, R., 1977. Transport in Porous Catalysts: Elsevier], which is considered to be the most accurate of the existing mass transfer models in porous media [Suwanwarangkul, R., Croiset, E., Fowler, M.W., Douglas, P.L., Entchev, E., Douglas, M.A., 2003. Performance comparison of Fick's, dusty-gas and Stefan-Maxwell models to predict the concentration overpotential of a SOFC anode. Journal of Power Sources 122, 9-18]. Our two-dimensional DGM is validated using experimental data [Yakabe, H., Hishinuma, M., Uratani, M., Matsuzaki, Y., Yasuda, I., 2000. Evaluation and modeling of performance of anode-supported solid oxide fuel cell. Journal of Power Sources 86, 423-431] and it is tested against a two-dimensional Stefan-Maxwell model (SMM) and against one-dimensional models (Fick's model, SMM and DGM) reported in the literature. It is shown that a detailed model is essential for the accurate prediction of concentration overpotentials especially at high fuel utilisation conditions, which are typical operating conditions for fuel cells [Hernández-Pacheco, E., Singh, D., Hutton, P.N., Patel, N., Mann, M.D., 2004. A macro-level model for determining the performance characteristics of solid oxide fuel cells. Journal of Power Sources 138, 174-186].     

二氯乙烷市场消费与发展前景

详细介绍了我国二氯乙烷(EDC)生产厂家的生产能力、产量、进出口情况以及发展前景。我国二氯乙烷的主要生产厂家是中国石化齐鲁股份有限公司、北京化二股份有限公司、江苏丹化集团有限责任公司和山东鲁岳化工有限公司。陶氏塑料、美国西方石油公司和台湾塑料集团是全球最大的二氯乙烷生产商,约占全球总产能的27%。     

氯乙烯装置新老氧氯化单元技术比较

对引进的三井东亚和赫司特乙烯氧氯化反应单元的结构、工艺情况及安全性进行了比较,并提出了改进建议。     

Analysis of flow in rotating packed beds via CFD simulations—Dry pressure drop and gas flow maldistribution

Three-dimensional unsteady-state turbulent rotating single-phase flows were simulated in rotating packed beds (RPB) and were validated using overall dry pressure drop measurements for three RPB designs [Liu, H.-S., Lin, C.-C., Wu, S.-C., Hsu, H.-W., 1996. Characteristics of a rotating packed bed. Industrial and Engineering Chemistry Research 35, 3590-3596; Sandilya, P., Rao, D.P., Sharma, A., Biswas, G., 2001b. Gas-phase mass transfer in a centrifugal contactor. Industrial and Engineering Chemistry Research 40, 384-392; Zheng, C., Guo, K., Feng, Y.D., Yung, C., 2000. Pressure drop of centripetal gas flow through rotating bed. Industrial and Engineering Chemistry Research 39, 829-834]. Analysis of the radial and tangential velocities highlighted the impact of gas feed entrance effects on the peripheral gas maldistribution in the rotating packing module. Recommendations were formulated for an optimum design with the aim to reduce gas flow maldistribution in RPBs. Breakdown of the overall pressure drop in its modular components for the housing, the rotating packing module, the free inner rotational zone, and the gas disengagement showed that the dissipation in the rotating packing could be a minor contributor to the overall pressure drop which may be undesirable in terms of RPB mass transfer and reaction efficiencies. Analysis of the simulated pressure drops allowed development of CFD-based Ergun-type semi-empirical relationships in which the gas-slip and radial acceleration effects, the laminar and inertial drag effects, and the centrifugal effect were aggregated additively to recompose the pressure drops in the rotating packing module.     

D-泛酸钙生产现状及市场分析

目前我国有10余家D-泛酸钙生产厂,合计生产能力超过9600 t/a,主要生产厂家有浙江杭州鑫富药业股份有限公司、上海嘉定新行医药化工集团有限公司、湖北富驰化工医药股份有限公司等;国外D-泛酸钙生产公司主要有日本第一制药精细化学品公司、BASF、DSM(原Roche)等。目前全球D-泛酸钙消费量大约9000 t/a,其中美国约3200 t/a、欧洲约2800 t/a、亚洲2500 t/a、拉美等地区500 t/a。D-泛酸钙主要应用领域为饲料添加剂、医药和食品工业。     

贵州地衣香料的开发及其在调香上的应用

通过对贵州地衣植物的资源调查、提香实验、调香运用 ,筛选出可作香料的地衣品种 ,它们是 :杯树花日本变种、拟树花、丛生树花、中国树花、裂树花、沟树发、扁条梅衣 ,并列举了运用实例     

Male and Female Noctuid Moths Attracted to Synthetic Lures in Europe

In field tests in Europe, traps baited with a blend of isoamyl alcohol, acetic acid, and isobutanol (compounds previously found attractive to a number of noctuids in North America) caught the following noctuid moths: Agrotis segetum Schiff., Agrotis crassa Hbn., Agrotis exclamationis L., Amathes (Xestia) c-nigrum L., Apatele rumicis L., Amphipyra pyramidea L., Dipterygia scabriuscula L., Discestra trifolii Hfn., Euxoa aquilina Schiff., Euclidia glyphica L., Mamestra brassicae L., Mamestra oleracea L., Mamestra suasa Schiff., Mythimna albipuncta Den. & Schiff., Mythimna l-album L., Noctua pronuba L., and Trachea atriplicis L. A substantial percentage of the catch of each species of moths was females. The presence of isobutanol in the mixture was important for catching A. rumicis, D. trifolii, and E. glyphica. The addition of 3-methyl-1-pentanol to the ternary mixture did not increase trap captures of any of the moths. Traps baited with the floral attractant phenylacetaldehyde alone caught several species of noctuid moths. However, when phenylacetaldehyde was added to the isoamyl-alcohol ternary blend, no increases in catches of any of the species, relative to the ternary blend or phenyacetaldehyde alone, were observed, with catches of most species being depressed. Comparing the noctuid species attracted to the phenylacetaldehyde- and isoamyl alcohol-based lures showed that phenylacetaldehyde attracted predominantly Plusiinae and Melicleptriinae spp., while isoamyl alcohol-based lures attracted species mostly from the Noctuinae or Hadeninae subfamilies.