浦项中子装置上209Bi中子全截面测量(英文)

在浦项中子装置(PNF) 的100 MeV电子直线加速器上利用透射法和飞行时间法测量了209Bi 的0.1~100 eV的中子全截面。文中对于实验装置特点、用吸收片法拟合本底、拟合中子飞行距离和时间零点的处理过程做了较为详细的描述。测量结果与以前发表的实验数据以及评价数据ENDF/B-VII.1 做了比较,比较结果符合得较好。     

Atomic Diffusion in Cu/Si （111） and Cu/SiO2/Si （111） Systems by Neutral Cluster Beam Deposition

The Cu films are deposited on two kinds of p-type Si （111） substrates by ionized duster beam （ICB） technique. The interface reaction and atomic diffusion of Cu/Si （111） and Cu/SiO2/Si （111） systems are studied at different annealing temperatures by x-ray diffraction （XRD） and Rutherford backscattering spectrometry （RBS）. Some significant results are obtained： For the Cu/Si （111） samples prepared by neutral dusters, the interdiffusion of Cu and Si atoms occurs when annealed at 230℃. The diffusion coefficients of the samples annealed at 230℃ and 500℃ are 8.5 ×10^-15 cm^2.s^-1 and 3.0 ×10^-14 cm^2.s^-1, respectively. The formation of the copper-silicide phase is observed by XRD, and its intensity becomes stronger with the increase of annealing temperature. For the Cu/SiO2//Si （111） samples prepared by neutral dusters, the interdiffusion of Cu and Si atoms occurs and copper silicides are formed when annealed at 450℃. The diffusion coefficients of Cu in Si are calculated to be 6.0 ×10^-16 cm^2.s^-1 at 450℃, due to the fact that the existence of the SiO2 layer suppresses the interdiffusion of Cu and Si.     

Direct Observation of Tunnelling through 100-nm-Wide All Metal Magnetic Junction into Si

Nanoscaled spin-dependent tunnelling lines were patterned on doped Si and studied for tunnelling from the SDT ferromagnetic layer through an insulating barrier into Si. The injection contacts have the form of long strips with width and separation, ranging from 100 nm to 2 μm, and are patterned using e-beam lithography. The measured I-V characteristics versus temperature （80 to 300K） on the 100 nm scaled devices between the layered-magnetic metals and the semiconductor clearly showed ballistic tunnelling, with weak dependence on the temperature. This is qualitatively different, at elevated temperatures, from 2-μm-wide scaled-up spin-dependent tunnelling structures, where thermal-ionic emission was observed to dominate carrier transport.     

Y1.95-xGdxSiO5:Eu0.05的真空紫外光谱

利用高温固相法合成了Ｙ１．９５－ｘＧｄｘＳｉＯ５：Ｅｕ０．０５（ｘ＝０．６ｍｏｌ％）荧光体。结构测定表明所合成的荧光体为单斜晶系的Ｘ２型Ｙ２ＳｉＯ５相,空间群为Ｂ２／ｂ。真空紫外光谱表明：随着Ｇｄ＾３＋含的增加,在１９２ｎｍ附近,出现了Ｇｄ＾３＋的激发峰,且此峰的强度随着Ｇｄ＾３＋含量的增加而增在;同时位于１５０￣１８５ｎｍ之间的基质吸收带的强度也增大;而位于２００￣３００ｎｍ之间的Ｅｕ的电荷迁移     

Propylene Polymerization by TiCl_4 Supported on Mg(OEt)_2 Activating with Ethanol/CO_2 System

For the preparation of high-active and high-isospecific catalysts for propylenepolymerization,various supports such as Mg-alkyls[1 ] ,Mg( OH) 2 [2 ] ,Mg O[3] ,Mg Cl2 [4] .Grignard compounds[5] ,or magnesium alkoxide[6] had been used.Lately,Mg( OEt) 2 -supported Ti Cl4catalysts including an organic chloride and/ or an internal donor preparedby physical milling method and chemical reaction method were studied and it was foundthat Mg( OEt) 2 is converted to Mg Cl2 by reaction with Ti Cl4a…     

SOUND TRANSMISSION THROUGH PERIODICALLY STIFFENED CYLINDRICAL SHELLS

A relatively long circular cylindrical shell stiffened by periodically deployed stiffeners is found in many practical applications such as the aircraft fuselage. For the sound transmission analysis of such a system, not only structural interactions between the shell and stiffeners but also vibro-acoustic interactions between the structure and acoustic media have to be considered. By idealizing the system as an infinitely long cylinder subjected to a plane wave incidence, an exact solution is obtained for the first time for this type of problem. In the analysis, the solution is obtained in a series form by expanding the system responses in terms of the space harmonics of the stiffener spacing. Characteristics of the system responses and effects of important design parameters are studied using the transmission losses calculated from the analysis.     

2，5-二烷基-1，4-苯二酚类衍生物的新合成方法

研究了合成2，5-二烷基-1，4-苯二酚衍生物的新方法，该方法是以2-取代烷 基1，4-环已二酮为原料，在LiCl催化下，与各种醛缩合反应就得2，5-二烷基-1， 4-苯二酚衍生物，是一种由非芳香环化合物合成2，5-二烷基-1，4-苯二酚衍生物 的新方法。应用该方法简便地合成了天然化合物η-生育酚。     

可紫外光固化的聚乙烯基硅氮烷合成与表征

采用带丙烯酸酯基团的烯丙基溴化合物(4-溴丁烯酸乙酯)和聚乙烯基硅氮烷发生取代反应,实现了丙烯酸酯基团在聚乙烯基硅氮烷主链上的链接.采用质子核磁共振谱(1H-NMR)和二维质子核磁共振谱(2D-1H-1H-NMR)对分子结构进行了表征,采用光学差热分析仪(Photo-DSC)和傅立叶转换红外光谱仪(FT-IR)测试了改性高分子的光敏性能,用热重分析仪(TGA)分析了产物在高纯氮气氛围下的陶瓷收率.结果表明,通过分子改性,交联固化时间从改性前的20min减少到1min之内,功能化的聚乙烯基硅氮烷可以在光刻蚀工艺中作为负性光刻胶使用.     

Synthesis of 3-Benzyloxy-6-methyl-7-methoxyphenanthrene-9-carboxaldehyde with Utilize Intramolecular Heck Reaction as the Key Step

The substituted phenanthrene-9-carboxyaldehydes are very important intermediates for the syntheses of phenanthroindolizidine and phenanthroquinolizidine alkaloids. The novel title compound was prepared from the reaction of 5 steps starting from the condensation of 3-methoxyl-4-methyl-phenylacetic acid and 4-（benzyloxy）-2-iodobenzaldehyde, followed by esterification, cyclization, reduction, and oxidation. A new method for the preparation of phenanthrene ring via palladium-catalyzed intramolecular Heck reaction was described. The title compound was characterized by IR, ^1H NMR, ^13C NMR, elemental analysis, and MS.