Systematics study through scanning electron microscopy; a tool for the authentication of herbal drug Mentha suaveolens Ehrh

In all over the world, herbal drugs are usually adulterated with similar species or varieties due to incorrect identification. Most of herbal products devoid purity and quality, therefore an attempt was carried out to identify plant species and authenticate its herbal drug products from Mentha suaveolens. Microscopy tools provide an excellent platform to identify plants at species level. In this study, microscopic and pharmacokinetic parameters of M. suaveolens were observed. Plant species were collected from high diverse areas of Northern Pakistan. Macro and micro‐morphology including palynology and anatomical features were analyzed to study M. suaveolens. Species characteristics were studied, while implementing microscopic techniques for the delimitation and identification of the species. Traditionally Mentha species are used to cure several diseases that is, digestive disorders, respiratory disorders. Micromorphology (stem, leaves, flowers structure, length etc.), palynology (shape, size of pollen etc.), and anatomical characters (types of stomata, epidermal cell shape, and trichomes) were studied. Micromorphology and anatomical characters were of great interest and significance to discuss the taxonomy of the species. Taxonomic characters were studied to characterize and authenticate the species. The aim of the present study is to observe in detail the taxonomic identification of the species in term of morphology, palynology, and foliar epidermal anatomy for the correct identification along with their medicinal uses in the area.     

PAM、PNaA和P(AM-NaA)水凝胶微观形态的分形研究

用辐射聚合方法合成的丙烯酰胺、丙烯酸钠的均聚物及其共聚物水凝胶，借助于扫描电子显微镜技术观察了组成不同的干态水凝胶聚合物的微观形态特征，探讨了不均匀的微观交联网络的分形特性，用分形维数对水凝胶聚合物的微观网络的致密程度进行了量化表征。结果表明，分形维数能够从整体上定量地表征水凝胶聚合物的不均匀微观网络之间随组成改变而产生的细微差异，而且，样品的微观网络愈致密则其分形维数值愈大。     

固相法氯化聚乙烯与聚氯乙烯共混物的形态与性能

研究了聚氯乙烯(PVC)与固相法氯化聚乙烯(CPE)共混物的应力-应变行为和冲击强度对CPE用量和氯含量的依赖关系,考察了共混物形态与性能的关系。动态力学性能和透射电子显微镜的研究结果表明,PVC/CPE为部分相容体系,两相间存在着一定的相互作用,当CPE氯含量为36％～42％,用量为7～15份时,CPE在PVC/CPE共混物中形成比较完整的网络结构、共混物具有更好的抗冲击性能。Brabender流变仪研究表明,CPE能促进PVC的塑化,共混物的加工性优于纯PVC。     

PU改性TDE-85/ MeTHPA环氧体系的显微形貌特征研究

本实验选用聚醚二元醇、甲苯二异氰酸酯（TDI）作为原料，合成了聚醚型聚氨酯预聚体。采用该预聚体扩链剂1，4-丁二醇（1，4-BDO）、交联剂三羟甲基丙烷（TMP）对TDE-85／甲基四氢苯酐（MeTHPA）环氧树脂体系行改性。利用扫描电镜分析，探讨了聚氨酯（PU）改性TDE-85／甲基四氢苯酐（MeTHPA）环氧树脂体系结构特征。结果表明，当合成PＵ预聚体的PPG相对分子质量不同时，改性环氧树脂体系的表面形貌随聚氨酯预聚体加入量的变趋势是相同的。当聚氨酯含量较小时，呈明显的“海岛”结构。随着聚氨酯加入量增多到一定量时，两网络互穿程度高，相分离程度不明显，具有互穿网络聚合物结构特征。随着聚氨酯含量的继续增多，相区尺寸明显增大，两相相容变差，相界面变得较清晰。     

丁苯橡胶对水泥水化过程及水泥石微观结构的影响

用多种实验手段研究了在普通硅酸盐水泥中掺入丁苯橡胶乳液对水泥水化过程的影响，并用扫描电镜分析了掺入丁苯橡胶后水泥石微观结构形态的改变，从而探讨了丁苯橡胶改善水泥石物理力学性能的机理。     

建筑用热轧奥氏体304不锈钢管力学性能

为了解热轧无缝不锈钢管材料性能,分别对取材自奥氏体304 Φ216×16 mm热轧不锈钢管的光滑和缺口圆棒试件进行单调和循环加载两类试验,获取了应力-应变关系及基本材料参数,得到滞回和骨架曲线,标定钢材循环强化参数,并观察了断面微观破坏特征．研究表明:国产热轧不锈钢管加工工艺对中厚管材性影响不大;奥氏体304不锈钢在循环荷载作用下具有良好强化效应和耗能性能;宜采用随动-等向混合强化材料模型描述其行为,所标定循环强化参数可用于复杂应力状态下的数值模拟;不锈钢材微观破坏特征异于普通低合金或低碳钢．     

高压XLPE电缆缓冲带动态导电特性与机理

高压XLPE电缆缓冲层烧蚀是近年来受到广泛关注的电缆故障类型。缓冲层烧蚀通常在受到挤压以及吸收水分的情况下发生,因此研究压强与吸水对于缓冲带烧蚀的影响机制具有重要的意义。文中针对干燥与吸水的缓冲带在不同压强下开展了模拟实验,获得了缓冲带电流密度、电压以及交流体积电阻率在烧蚀过程中的动态变化规律;采用扫描电子显微镜,获得了缓冲带试样的微观形貌特征。结果表明：在烧蚀过程中,干燥缓冲带试样的交流体积电阻率随时间逐渐升高,并伴随有短暂电流激增同时电压骤降的现象;吸水后缓冲带试样交流体积电阻率会出现随时间逐渐降低的过程,并且吸水后缓冲带交流体积电阻率有所下降。当压强从1.09kPa增加至5.45kPa时,干燥与吸水缓冲带试样的交流体积电阻率均逐渐降低。结合缓冲带烧蚀模拟实验结果以及微观形貌特征,解释了压强与吸水对缓冲带动态导电特性的影响机理。     

Comparative morphology of leaf epidermis in eight populations of Atlas Pistachio (Pistacia atlantica Desf., Anacardiaceae)

A comparative analysis was undertaken to conduct a micromorphological study of Pistacia atlantica leaves by comparing different populations grown under different climatic conditions. Leaf epidermis of eight wild populations was investigated under scanning electron microscope. Micromorphological characteristics (epidermis ornament, stomata type, waxes as well as trichomes) of the adaxial and abaxial leaf surfaces were examined. The epidermis ornament varied among populations and leaf surface, the abaxial leaf surface is reticulate with a striate surface. Messaad site shows a smooth uneven surface. The adaxial leaf surface is smooth but several ornamentations can be seen. The leaflet is amphistomatic; the stomata appeared to be slightly sunken. A variety of stomatal types were recorded; actinocytic and anomocytic types are the most frequent. The indumentum consisted of glandular and nonglandular trichomes. Unicellular glandular trichomes are recorded for P. atlantica leaves in this study. Their density is higher in Oued safene site, located at the highest altitude in comparison with the other populations. The wax occurred in all the sites and its pattern varied according to the populations studied, particularly between Berriane and Messaad. The morphological variability exhibited by the eight populations of P. atlantica may be interpreted as relevant to the ecological plasticity and the physiological mechanisms involved are discussed in this report.     

Water‐absorption characteristics of organic–inorganic composite superabsorbent polymers and its effect on summer maize root growth

Adding inorganic materials in SAPs to synthesize organic–inorganic composite superabsorbent polymers (OICSAPs) can effectively improve salt‐tolerance, gel strength, thermal stability, and water retention. However, most researches mainly focus on synthesizing process optimization and new multifunctional products, lacking reports on how ions affected water‐absorption characteristics and mechanism of OICSAPs and its influence on summer maize root growth. On the basis of these, we set up laboratory experiments and field cultivation experiment, using environmental scanning electron microscopy (ESEM) and fractal theory to study the questions above. Results show that OICSAPs have better salt‐tolerance, while cations and concentration affected its water‐absorption characteristics significantly. With higher cation valence, larger ionic radius, and concentration, its water‐absorption rate reduced remarkably as Na⁺ < K⁺ < Mg²⁺ < Ca²⁺ < Fe²⁺ < Fe³⁺ < Al³⁺ < Cu²⁺, while the effects of anions could be neglected. The OICSAPs presented typical honeycomb membrane‐like 3D crosslinked network structure, but Ca²⁺, Mg²⁺, Fe²⁺, Fe³⁺, Al³⁺, and Cu²⁺ would damage the structure (Cu²⁺ with the most significant effect) in local microdomain, and changed the complexity of pores. In the experiment, higher concentration could reduce water‐absorption rate without changing micromorphological characteristics. Applying OICSAPs will reduce total length, surface area, and volume of summer maize root, while promoting absorbing and transmitting ability by larger root diameter and the proportion of root <0.5 cm. All these results will provide a theoretical basis on application, marketing, and product development of OICSAPs. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

增容高抗冲聚苯乙烯/高乙烯基聚丁二烯橡胶热塑性硫化胶的Mullins效应及其可逆性

采用动态硫化法制备了苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)增容高抗冲聚苯乙烯(HIPS)/高乙烯基聚丁二烯橡胶(HVPBR)热塑性硫化胶(TPV),考察了SBS用量对TPV物理机械性能的影响,表征了TPV的微观形貌,并研究了TPV的Mullins效应及其可逆性。结果表明,SBS可显著改善HIPS/HVPBR体系的相容性,其用量为12份时,TPV的物理机械性能较好;SBS增容TPV的断面平整、结构致密,界面相互作用明显增强;SBS增容TPV在循环单轴拉伸过程中出现明显的Mullins效应,提高应变速率时,TPV的最大应力和内耗呈增大趋势,瞬时残余形变则减小;当拉伸比相同时,TPV经第1次拉伸热处理后,第2次单轴拉伸中TPV的最大应力和内耗均增大,瞬时残余形变则减小。