热障涂层材料性能和失效机理研究进展

热障涂层材料破坏由大尺度屈曲和层离机制产生, 而这些机制又是微裂纹形核、扩展及相互连通结果的积累.由于特殊制备工艺和使用环境, 材料性能涉及到许多特殊机制.近半个世纪的研究,人们对其性能有了充分认识.综述 近几年的研究结果,内容包括:热生长氧化现象及其热力学描述;热生长应力与材料失效的联系;材料破坏机理与性能 控制参数和材料微组织的联系;微缺陷演化产生的材料屈曲和层离所需的能量释放率;破坏 准则、服役寿命预计模型和评价标准等.     

异淀粉酶产生菌的分离纯化及生长特性

自然界是微生物的大本营，工业微生物几乎都是从自然界选育来的。我们从兰州市淀粉厂附近的土壤中分离到产异淀粉酶的菌株，将样品于富集培养基中进行富集养后，分离、纯化筛选出酶活较高的菌株，对其进行了鉴定。依据新版伯杰细菌鉴定手册，鉴定该菌株为地衣芽胞杆菌（Bacillus Licheniformis)，与文献^[1,2]中所报道的异淀粉酶菌的产生菌是一致的对该菌株的生长特性进一步研究的结果是2－18小时是该菌的对数生长期，在16小时时菌体生长最快，18小时以后菌体生长进入稳定期。菌体32℃摇瓶发酵培养不同时间后能在540nm处测基OD值计算其酶活发现该菌的产酶是伴随着菌体的生长同时发生的，当菌体生长达稳定期后，产酶量迅速增加，到48小时，产酶量达最多，48小时以后产酶量逐渐趋于稳定。     

Electrochemical Detection of Catechol Based on As‐Grown and Nanograss Array Boron‐Doped Diamond Electrodes

The electrochemical behavior of different redox systems and detection of catechol were performed on the as‐grown boron‐doped diamond (BDD) electrodes and the nanograss array BDD. Compared with as‐grown BDD, the electron transfer on the nanograss array BDD surface became slower toward the negatively charged Fe(CN)₆^3?, whereas changed little toward the positively charged Ru(NH₃)₆³⁺. The nanograss array BDD showed higher electrocatalytic activity toward the catechol detection than did the as‐grown BDD. Good linearity was observed for a concentration range from 5 to 100 μM with a sensitivity of 719.71 mA M^?1 cm^?2 and a detection limit of 1.3 μM on the nanograss array BDD.     

Surface‐enhanced Raman spectroscopy of genomic DNA from in vitro grown plant species

Surface‐enhanced Raman scattering (SERS) effect was used to demonstrate ultrasensitive optical detection of nucleic acids. In this work, the SERS spectra of seven genomic DNAs from leaves of Arnica montana (L.), Fam. Compositae, Astragalus peterfii (Jáv.), Fam. Fabaceae, Kalanchoe x hybrida, Fam. Crassulaceae, strawberry (Fragaria x ananassa Duch.), Fam. Rosaceae, carnation (Dianthus caryophyllus L.), Fam. Caryophyllaceae, apple (Malus domestica Borkh.), Fam. Rosaceae and Persian violet (Exacum affine Balf.), Fam. Gentianaceae were analyzed in the wavenumber range 200–1800 cm⁻¹. SERS signatures, spectroscopic band assignments and structural interpretations of these plant genomic DNAs are reported. SERS spectra of nucleic acids are compared here with caution, because these signals are time‐dependent. The SERS spectra corresponding to DNA from Arnica, Dianthus, Fragaria and Kalanchoe leaves show well‐resolved, accurate bands, providing thus a high molecular structural information content. Based on this work, specific plant DNA–ligand interactions or DNA structural changes induced by plant stress conditions associated with their natural environment might be further investigated using SERS spectroscopy. Besides, this study will generate information that is valuable in the development of label‐free DNA‐based nanosensors for chemical probing in the living cell. Copyright © 2011 John Wiley & Sons, Ltd.     

同步辐射XRF法分析温室油菜中微量元素的分布

蔬菜是补充人体微量元素的重要途径,但是蔬菜不同部位、特别是温室蔬菜不同部位各种元素的分配目前还没有研究清楚。利用同步辐射XRF法测定了温室油菜中各种微量元素中的分配情况。研究结果表明温室油菜中含有许多人体必需的微量元素,特别是Ca,Mn,Fe,Cu和Zn;但是不同的元素在叶片和根系的不同部位含量有所差异,总体上油菜根系中K,Ca和Mg的含量显著高于叶片,叶片中Fe,Zn,Co,Ni和Cu的含量则高于根系,其中侧根中的各种元素含量均很低。K,Ca和Co在叶片中间位置含量较高,由边缘向中部含量逐渐增加;Cu,Mn,Fe和Ni含量由叶片基部到叶尖处含量逐渐增高;Zn总体含量也比较均匀。在主根中各种元素普遍表现为根基部向根尖呈现先上升再降低的规律,根系中间部位各元素含量高,且普遍表现为根基部的含量要高于根尖处的含量。     

中国区域污染物增长份额-偏移分析

基于汇总各类污染物排污费,应用份额偏移分析方法解析中国各地区自2004～2010年以来区域污染增长,通过对比结构偏移分量和竞争力偏移分量,探索中国各区域污染治理改进方向,最后按照各区域所属扇区,中国各区域产业生态化空间组织结构划分为综合优势区、竞争优势区、结构优势区和优势欠缺区.     

Kinetically Limited CO Adsorption: Spill-Over as a Highly Effective Adsorption Pathway on Bimetallic Surfaces

We demonstrate that the (local) adsorbed carbon monoxide, CO_ad, coverage on the Pt-free areas of bimetallic Pt/Ru(0001) surfaces (a Ru(0001) substrate partly covered by Pt monolayer islands) can be increased to ∼0.80 monolayers (ML), well above the established saturation CO_ad coverage of 0.68 ML, even under ultrahigh vacuum conditions by using spill-over of CO adsorbed on the Pt islands to the Ru areas as an highly effective adsorption channel. The apparent CO_ad saturation coverage of 0.68 ML on pure Ru(0001) is identified as due to kinetic limitations, hindering further uptake from the gas phase, rather than being caused by thermodynamic reasons. This spill-over mechanism is proposed to be a general phenomenon for adsorption on bimetallic surfaces.     

Crystalline β‐structure of PHBV grown epitaxially on silicate layers of MMT

The poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV)/montmorillonite(MMT) nanocomposites were investigated by wide‐angle X‐ray scattering (WAXS). The aim of the investigation was solution intercalation of MMT with PHBV. Beside the usual orthorhombic unit cell, a stable pseudohexagonal β‐structure of PHBV was obtained. Well known β‐structure has one common WAXS reflection (d = 0.480 nm), which corresponds to the mean distance of PHBV chains in the pseudohexagonal structure. The new β‐structure has two diffraction peaks in the WAXS pattern. It is a three‐dimensionally ordered crystalline structure oriented in parallel with the silica layers of MMT. The new polymorphic form is supposed to be growing on the layers of MMT. Its layers serve as primary nucleation centers for epitaxial growth of the β‐structure. After annealing, this polymorphic form of PHBV disappears and it is transformed into the more stable α‐form leading to an enhanced total crystallinity of the polymer comprised in the nanocomposite. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 751–755, 2009     

CHARACTERIZATION AND ADSORPTION PROPERTIES OF POROUS CARBON NANOFIBER GRANULES

The properties of the porous granules produced by agglomeration of catalytically grown carbon nanofibers were investigated in this work. The single pellet crushing strength of the granules is high, e.g., 1.6-2.5 MPa. They have high specific surface areas, averaging 72-141 m^2·g^-1, and the majority of their pores are mesopores or macropores. The adsorption at 298 K of benzene or phenol on the granules is much lower than that on activated carbon and depends not only on the specific surface area of the carbon material but also on the sewing structure of the granules and the morphology of the carbon nanofibers. Treatment in dilute nitric acid appreciably reduces such adsorption.