晶体管构成R-232C数字温度计

一只普通的晶体管就能起到未校准的温度敏感器(图1)作用,而用作精密的PC兼容的温度计,在-50～+50℃范围内,未经调整的精度高于0.5℃,分辨力方面唯一约束是专门进行测量采集的时间。例如,0.1℃分辨力要求采集时间小于1秒。该温度计从RS-232C COM端口得到其全部功率,因此,运行一个简单的数据记录编程的膝上     

利用氟化气体和氧气的混和物进行SiC薄膜的反应离子刻蚀

本文研究了在ＳＦ６，ＣＢｒＦ３和ＣＨＦ３与氧相混合的几种氟化气体等离子体中，ＳｉＣ薄膜反应离子刻蚀（ＲＩＥ）的深度。通过监测射频等离子体的光发射谱及产生等离子体的直流偏压来研究刻蚀机理，为了更精确地定量分析刻蚀工艺，使用氩光能测定技术使等离子发射强度转换为相应的等离子物质浓度。为获得选择性的ＳｉＣ－Ｓｉ刻蚀及ＳｉＣ薄膜的各向异性图形，对等离子体条件，如气体混合物的构成，压力和功率进行了研究。首次采     

Studies on synthesis and infrared and fluorescence spectra of new europium and terbium complexes with an amide-based open-chain crown ether

An amide-based open-chain crown ether ligand and its complexes with europium and terbium were synthesized. The complexes were characterized by elemental analysis, infrared spectra and conductivity. The europium and terbium ions were found to coordinate to the C=O oxygen atoms and pyridine nitrogen atoms. The fluorescence properties of these complexes in DMF and CH3OH/CHCl3 were studied. Under the excitation of UV light, these complexes exhibit characteristic fluorescence of europium and terbium ions. The solvent factors influencing the fluorescent intensity are discussed.     

Selective binding of the cyano group in acrylonitrile adsorption on Si(100)-2 x 1

The covalent binding of acrylonitrile (CH(2)=CH-C triple bond N) and the formation of a C=C-C=N structure on Si(100) have been investigated using high-resolution electron energy loss spectroscopy (HREELS), X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and density functional theory (DFT) calculations. For chemisorbed acrylonitrile, the absence of nu(C triple bond N) at 2245 cm(-1) and the appearance of nu(C=N) at 1669 cm(-1) demonstrate that the cyano group directly participates in the interaction with Si(100), which is further supported by XPS and UPS observations. Our experimental results and DFT calculations unambiguously demonstrate a [2 + 2] cycloaddition mechanism for acrylonitrile chemisorption on Si(100) through the binding of C triple bond N to Si dimers. The resulting chemisorbed monolayer with a C=C-C=N skeleton can serve as a precursor for further chemical syntheses of multilayer organic thin films in a vacuum and surface functionalization for in situ device fabrication.     

Evidence for a nonradical pathway in the photoracemization of aryl sulfoxides

Photolysis of (R(S),S(C))-1-deuterio-2,2-dimethylpropyl p-tolyl sulfoxide provides mainly (S(S),S(C))-1-deuterio-2,2-dimethylpropyl p-tolyl sulfoxide at low conversion, though the other two stereoisomers are formed to smaller extents. Thus, the predominant process leading to sulfur inversion yields only sulfur inversion, without inversion of the adjacent CHD stereogenic center. This is taken as evidence for a mechanism for photochemical epimerization of sulfoxides that does not involve homolytic alpha-cleavage chemistry.