应力对La0.83Sr0.17MnO3薄膜输运性能的影响

采用溶胶-凝胶方法在Si(111)上制备了LSMO(x=0.17)薄膜.研究了块体材料和不同厚度薄膜R -T曲线、红外光谱和X射线衍射.结果表明，LSMO薄膜属于正交晶体结构，薄膜取向与膜厚度 有关，当膜厚度为450nm或680nm时，主要取向〈200〉，而膜厚度为900nm时取向为〈020〉 ：根据离子对相互作用能和谐振子模型，得到了红外吸收与Mn—O—Mn键长和键角关系式，6 00cm^-1附近红外吸收与晶格常数b的变化有关；块体与薄膜的金属—绝缘体转变 温度(T_MI)存在较大差别，薄膜转变温度显著低于块体，并与厚度有一定关系. 认为是LSMO薄膜中的应力诱导了晶格常数变化，引起键角改变及JT效应是转变温度变化的主 要原因. 关键词： 单晶硅 晶格常数 金属—绝缘体转变温度 应力诱导     

On the origin of 1.5 μm luminescence in porous silicon coated with sol–gel derived erbium-doped Fe2O3 films

Sol–gel derived Fe₂O₃ films containing about 10 wt% of Er₂O₃ were deposited on porous silicon by dipping or by a spin-on technique followed by thermal processing at 1073 K for 15 min. The samples were characterized by means of PL, SEM and X-ray diffraction analyses. They exhibit strong room-temperature luminescence at 1.5 μm related to erbium in the sol–gel derived host. The luminescence intensity increases by a factor of 1000 when the samples are cooled from 300 to 4.2 K. After complete removal of the erbium-doped film by etching and partial etching the porous silicon, the erbium-related luminescence disappears. Following this, luminescence at 1.5 μm originating from optically active dislocations (“D-lines”) in porous silicon was detected. The influence of the conditions of synthesis on luminescence at 1.5 μm is discussed.     

钢中Si、Mn的电子探针定量分析与标样

采用特制的Fe-Si、Fe-Mn合金系列标样，用电子探针测定了钢或铁基合金中低含量的Si和Mn元素、与用纯元素作标样、经ZAF修正的结果相比较，提高了分析准确度．     

杂氮硅三环成环反应的研究

本文报导了与硅原子直接相连的有机基团(R)对杂氮硅三环成环速率的影响。利用气相色谱检测成环反应的产物之一——乙醇的生成速率和数量,并同与硅相连的R基团对成环反应速率的影响作比较。实验结果表明五种杂氮硅三环成环速度顺序为Cl_2CH—>ClCH_2—>ClCH_2CH_2CH_2—>CH_2=CH—>CH_3—,这与理论推断相符。     

Immobilization of thiabendazole-specific monoclonal antibodies to silicon substrates via aqueous silanization

Monoclonal antibodies specific for thiabendazole were immobilized to silicon, silicon dioxide, stoichiometric silicon nitride, and silicon-rich silicon nitride surfaces. This work provides the foundation for the development of a homogeneous sensor system for rapid detection and quantification of thiabendazole residues in produce and animal tissue. Immobilization was performed via aqueous silanization of the substrate followed sequentially by treatment with glutaraldehyde and contact with antibody solution in the presence of detergent. Surfaces were challenged with thiabendazole-horseradish peroxidase conjugate in an ELISA format to estimate immobilized antibody load. A stable and reproducible surface loading of 2 x 10¹¹ antibodies/cm² was obtained only after surfaces received postimmobilization treatments to remove nonspecifically adsorbed antibody. No difference in surface loading was noted when using 30% hydrogen peroxide rather than nitric acid for silanol activation. Little difference was noted among the antibody loadings achieved on the various silicon substrates. Bound antigen-enzyme conjugate was eluted with 0.1N acetic acid and reproducible surface activity was measured for up to four consecutive antigen challenges. Immobilized antibody surfaces were stabilized with 2% sucrose, dehydrated at 37‡C and stored in vacuum or stored at 4‡C in phosphate buffered saline containing 0.01% sodium azide without significant loss of activity.     

多孔硅的电化学制备

单晶硅在氢氟酸溶液中阳极氧化可制得多孔硅, 多孔硅是一种以新形态存在的硅, 与单晶硅相比, 它表现出独特的物理性质和化学活性。荧光光谱峰的蓝移表明, 在p-型低掺杂衬底硅上形成的多孔硅中存在量子尺寸效应, 新近获得的Raman光谱也证实了这一点。     

Mass spectrometric analysis of low molecular mass polyesters by laser desorption/ionization on porous silicon

A low molecular mass polyester was analyzed by desorption/ionization on porous silicon (DIOS) mass spectrometry. The results were compared with those of matrix-assisted laser desorption ionization (MALDI) mass spectrometry using matrixes of alpha-cyano-4-hydroxycinnamic acid (CHCA) and 10,15,20-tetrakis(pentafluorophenyl)porphyrin (F20TPP). The CHCA matrix was not suitable for characterization of low molecular mass components of the polyester because the matrix-related ions interfered with the component ions. On the other hand, the F20TPP matrix showed no interference because no matrix-related ions appeared below m/z 822. However, the solvent selection for determining optimal conditions of sample preparation was limited, because F20TPP does not dissolve readily in any of the available organic solvents. In the DIOS spectra, the polymer ions were observed at high sensitivity without a contaminating ion. No matrix is needed for DIOS spectra of low molecular mass polyesters, facilitating sample preparation and selectivity of a precursor ion in post-source decay measurements.     

XPS,AFM, ATR and TPD evidence for terraced,dihydrogen terminated, 1×1 (100) silicon

Heating (100) silicon at high temperature (say, higher than 850 °C) in H₂, cooling to 670–700 °C in the same ambient, and quenching to room temperature in N₂ results in environmentally robust, terraced 1 × 1 (100) SiH₂. Evidence for this conclusion is based on angle‐resolved x‐ray photoelectron spectroscopy, atomic force microscopy, infrared absorption spectroscopy in the attenuated total reflection mode, thermal programmed desorption, and reflection high‐energy electron diffraction. Copyright © 2005 John Wiley & Sons, Ltd.