麦秆/SPI润湿性和X射线光电子能谱分析(英文)

[目的]为了改善麦秆表面胶接性能以制备大豆分离蛋白胶黏剂麦秆刨花板,分别对麦秆表面进行化学处理和酶处理。[方法]通过接触角测量和计算扩散-渗透系数(K),对未处理(对照试样)和两种化学处理及三种酶处理麦秆的麦秆表面润湿性进行评价分析,并通过X射线光电子能谱(XPS)对处理试样和对照试样进行表面元素分析。[结果]结果表明氢氧化钠处理、过氧化氢处理以及脂肪酶处理后的麦秆表面扩散-渗透系数K值同对照试样相比,分别提高了58.0%,48.7%和83.2%。XPS分析表明处理后的麦秆表面硅元素含量的急剧减少和蜡质层的破坏都为麦秆表面润湿性的改善起到了很重要的作用。[结论]麦秆化学处理和脂肪酶处理为豆胶麦秆刨花板的制备提供了技术支持。     

Cavity Formation in Thin Films of Viscous Liquids

High-speed photography was utilized to observe the dynamic growth behavior of a cavity in a viscous liquid. From these observations it has been shown that a relatively elementary analytical approach will reproduce the general cavity growth characteristics.     

电致发光有机薄膜中载流子的输运

研究电致发光有机薄膜中载流子的输运过程，迁移率是描述输运过程的关键物理量。根据载流子在格点间跳跃（hopping)输运理论，提出了一个有机薄膜中载流子输运的理论模型，推导出了迁移率的理论公式，以聚对苯乙炔（poly(p-phenylene vinylene)为例，数值计算了其在不同温度和电场下的迁移率，与实验符合得很好。     

梯度扩散薄膜技术（DGT）的理论及其在环境中的应用I：工作原理、特性与在土壤中的应用

根据文献资料,详细阐述了梯度扩散薄膜技术(DGT)的原理、影响DGT技术测量的因素和它的应用特性,同时回顾了DGT技术问世以来在土壤中的应用实例,并认为DGT技术为研究土壤重金属的生物可利用性提供了可行可靠而又有效的方法.     

X-ray Absorption Spectroscopic Investigation of Trace Vanadium Sites in Coal

X-ray absorption spectroscopy was used to probe the chemical and structural environment of vanadium in coal. It was found that vanadium exists in at least two environments, in both of which it was coordinated to oxygens. There was no evidence of vanadium in nitrogen (porphyrin) or sulfide environments. It was also found that the vanadium environments in the raw coal did not survive unchanged in a liquefaction process. These findings have implications for coal cleaning processes and for trace element release into the liquefaction process stream.     

Mn_2O_3薄膜磁学性能研究

利用外延技术制备Mn2O3薄膜,研究不同的衬底对薄膜磁学性能的影响。研究结果表明Mn2O3薄膜具有室温铁磁性,呈明显磁滞回线。同时通过对比研究,发现衬底掺杂与否对薄膜磁学性能有很大的影响,这表明薄膜性能与衬底之间的依赖关系。     

High-Density Nanosecond Charge Trapping in Thin Films of the Photoconductor ZnODEP

An electrooptical memory effect is observed with solid thin films of the photoconductor zinc-octakis(beta-decoxyethyl) porphyrin (ZnODEP) sandwiched between two optically transparent electrodes. Upon irradiation with the simultaneous application of an electric field, electron-hole pairs are generated and separated within the photoconductive layer. These electron-hole pairs become "frozen" within the films when the irradiation is interrupted. These trapped charges can be released by irradiation of the cell, resulting in a transient short-circuit photocurrent. No cross talk between adjacent memory elements separated by approximately 0.2 micrometer (a density of 3 gigabits per square centimeter) was detected. The charge storage system is robust and nonvolatile. The response time for the write-read beam is in the subnanosecond range, and no refreshing is required for long-term retention of trapped charges.     

基于XPS的马尾松褐腐降解研究

采用XPS分析马尾松素材及其防腐处理试件表面氧碳比(O/C)前后差异、C1s谱峰变化情况,评估香樟木质部蒸馏水提取物和樟脑防腐剂处理马尾松试样的耐腐效果。结果表明：褐腐后试样相比腐朽前表面C1s峰面积增加,O/C比减小,C1峰面积增大而C2减小,可见褐腐菌对各试样均有一定的降解效果;樟脑防腐剂处理马尾松试件褐腐后的O/C高于马尾松素材,C2降低幅度最小,而香樟木质部蒸馏水提取物处理马尾松试件褐腐后的O/C小于马尾松素材,C2降低幅度最大,证明樟脑处理马尾松试样对密粘褶菌具有一定的抑制效果,而香樟木质部蒸馏水提取物的防腐效果不明显。     

活性氧和一氧化氮在植物-病原体互作反应中的作用

植物被病原体感染后,植物体内活性氧产量急剧增加,这一现象被称为氧爆。活性氧族包括如单线态氧^1O2、超氧阴离子自由基O2^-、氢过氧自由基HO2·、过氧化氢H2O2、羟自由基·OH等。与ROS关系密切的一氧化氮,属于活性氮族。ROS和NO参与植物生长发育调控和对环境胁迫的应答反应,特别是在对抗外来病原体的入侵的防卫过程中发挥了重要作用。本文主要讨论ROS和NO在植物与病原体相互作用中发挥的作用。     

Giant Magnetoresistance at Low Fields in Discontinuous NiFe-Ag Multilayer Thin Films

A series of sputtered multilayers of Ni(80)Fe(20)-Ag was prepared to examine the giant magnetoresistance effect before and after annealing. For a wide range of NiFe and Ag thicknesses, no giant magnetoresistance was observed in the unannealed films. After annealing, a large, negative magnetoresistance was observed of order 4 to 6% in applied fields of order 5 to 10 oersteds at room temperature. The appearance of giant managetoresistance is concurrent with the breakup of the NiFe layers, which is attributable to a magnetostatic interaction that favors local antiparallel alignment of the moments in adjacent layers. These structures may be of significant practical importance as sensors that require large changes in resistance at low fields, such as magnetoresistive heads used in magnetic recording systems.     

化学气相沉积金刚石薄膜的表面过程

采用简单表面反应模式，对化学气相沉积金刚石薄膜的表面动力学过程进行了研究，得到了金刚石薄膜的沉积速率公式，揭示了影响薄膜生长的因素并由此讨论了金刚石薄膜生长的机制和规律。     

改进型过氧钼酸法制备无定形MoO3薄膜

通过金属钼粉与H2O2反应制得过氧钼酸溶胶液后，减压蒸馏除去过氧钼酸溶液中的溶剂水和过量的H2O2，再加入无水乙醇作为溶剂，采用浸泽一提拉法成功地在玻璃表面制备了平整均匀的无定形MoO3薄膜．并通过热分析和X射线衍射分析等对MoO3薄膜的制备机理进行了探讨．     

重金属胁迫与植物矿质元素交互作用的研究进展

近年来,重金属污染对农作物的影响越来越大,学者们就重金属对植物的毒害作用做了大量的研究。必需矿质元素是植物正常生长发育不可或缺的,而重金属胁迫会导致植物对必需矿质元素的吸收发生变化,进而影响植物的生理代谢。同时,矿质元素在一定条件下对重金属胁迫也具有一定的缓解作用。概述了几种主要重金属(Cd、Pb、Cu、Zn、Hg、As等)与植物矿质元素(Fe、S、P等)的交互作用,以期为提高植物重金属抗耐性提供一定的理论依据。     

X-ray Absorption Spectroscopic Investigation of Sulfur Sites in Coal: Organic Sulfur Identification

High-resolution x-ray absorption spectroscopy was used to probe the chemical and structural environments of sulfur in coal. Measurement of the sulfur Kedge spectra down to 2472.0 electron volts under nonvacuum conditions was made possible in an all-helium path, and a Stern-Heald type ion chamber was used for fluorescence detection. For a number of selected sulfur-containing minerals and organic model compounds, results show that near-edge spectral features are diagnostic for sulfur in specific organic moieties such as thiols, disulfides, and various heterocyclics, as well as in mineral sulfide and sulfate phases. The spectrum of a model system containing 35 percent iron pyrite and 65 percent benzothiophene was found to match the observed spectral features of a bituminous coal from the eastern United States.     

硫化温度和时间对SnxSy薄膜结构和成分的影响

用热蒸发技术在玻璃基片上沉积一层sn薄膜,在真空条件下,将其在150～300℃下硫化30．60min．对在不同温度和时间下硫化的薄膜进行结构、成分和表面形貌分析,结果表明：在不同温度和不同时间下硫化,所得到的薄膜在物相结构、成分和表面形貌上都存在差异．当硫化温度为240℃、硫化时间为45min时,所制得的薄膜为正交结构的SnS多晶薄膜,其均匀性、致密性以及对基片的附着力都较好,具有（111）方向优先生长,薄膜粒径在200～800nm,且晶格常数与标样的数值吻合很好．     

Local Control of Microdomain Orientation in Diblock Copolymer Thin Films with Electric Fields

Local control of the domain orientation in diblock copolymer thin films can be obtained by the application of electric fields on micrometer-length scales. Thin films of an asymmetric polystyrene-polymethylmethacrylate diblock copolymer, with cylindrical polymethylmethacrylate microdomains, were spin-coated onto substrates previously patterned with planar electrodes. The substrates, 100-nanometer-thick silicon nitride membranes, allow direct observation of the electrodes and the copolymer domain structure by transmission electron microscopy. The cylinders aligned parallel to the electric field lines for fields exceeding 30 kilovolts per centimeter, after annealing at 250°C in an inert atmosphere for 24 hours. This technique could find application in nanostructure fabrication.     

X-ray Diffraction Studies of Echinoderm Plates

X-ray diffraction studies confirm that, with few exceptions, each skeletal element of echtinoderms is a single crystal of magnesium-rich calcite and that a relation exists between the shape of the element and the crystallographic a- and c-axes. The exceptions incluide the teeth of echinoids, and the calcareous ring as well as the anal teeth of holothurians. The tubercles of an echinoid plate begin their growth as parts of the single crystal of the plate; under the mechanical action of the spines that are attached to them, they become partly polycrystalline, as shown by scanning electron microscopy and by x-ray powder diffraction. The interface between inorganic crystalline and organic amorphous matter in the skeletal element appears to be the first example reported in nature of a periodic mninimal suirface.     

水土重金属污染的危害及防治对策

综述了水土重金属污染的现状,阐述了重金属污染对生物体的危害及防治措施,提出发展绿色农业是解决我国重金属污染的根本出路。     

一氧化氮在植物响应重金属胁迫中的作用

一氧化氮(Nitric oxide,NO)是一种具有扩散性的气体分子,在哺乳动物中被鉴定为血管内皮细胞舒张因子,是一种有效的内源性血管舒张药。植物也具有合成和释放NO的能力,NO在植物中参与多种生理过程和胁迫响应。因此,NO被认为是植物及动物体内重要的气体信号分子。近年来,由于各种人类活动的影响导致重金属对农业生态环境造成了越来越严重的污染,威胁农作物生产与食品安全。尽管重金属影响植物生长发育的机制并不完全清楚,但越来越多的证据显示NO是植物体内响应重金属胁迫的重要成分之一。就目前重金属胁迫对植物内源NO的代谢以及外源NO对植物重金属毒害的影响的研究进展进行了综述。     

中性氧化铝作为吸附剂对土霉素薄层层析的效果测定

通过以中性氧化铝为吸附剂，０．５％ＣＭＣ－Ｎａ为粘合剂，在展开剂分别为９５％乙醇－１ＮＨＣｌ、正丁醇－１ＮＨＣｌ、正丁醇－１ＮＨＣｌ－水、甲醇－１ＮＨＣｌ和甲醇－１ＮＨＣｌ－水中对土霉素的层析效果研究，结果表明：中性氧化铝在上述５种展开剂中均不能使土霉素达到有效分离。故不能用中性氧化铝单独作为吸附剂对土霉素进行层析分离。