Stability of hydrogenated nanodiamonds under extreme ultraviolet irradiation

It is generally accepted that diamond is resistant to a wide spectrum of electromagnetic radiation from the ultraviolet through to the soft X-ray range, which makes it very attractive for the fabrication of diamond-based photodetectors. However the effect of photon radiation on the diamond structure has not yet been examined. In the work presented here, photoelectron spectroscopy has been used to study the graphitization of nanodiamond crystallites exposed to extreme ultraviolet radiation. Under such irradiation, the surface hydrogen groups and graphite species are found to prevent graphitization. The mechanism of radiation-induced nanodiamond graphitization is discussed.     

Characteristics of origin-destination pair traffic in Funet

In this paper we analyze measurements gathered from a 2.5~Gbps link in the Finnish university network (Funet) in 2004. The traffic is broken down into origin-destination (OD) pair components based on source and destination IP address. We study the traffic characteristics of these components, and identify four typical representative OD pairs. For these pairs we investigate the validity of a moving IID Gaussian model. We find that the statistical properties of these OD pairs differ significantly from each other, with only some of them close to Gaussian. The OD pairs are also found to have some cross-correlation between each other, contradicting an often made assumption about OD pair independence. Furthermore, the existence of a mean-variance relation between the OD pairs is studied. We find that there is a relation between mean and variance, but for some periods of time it is rather weak.     

注射成形粘结NdFeB磁体:工艺·性能·应用

综合介绍了几种适于注射成形粘结NdFeB磁体的磁粉制备方法及特点；讨论了粘结剂、改性剂及磁场取向对注射成形NdFeB磁体最终磁性能的影响及其应用市场。在此基础上，指出了今后开展研究工作的方向。     

Electrical characterization of homoepitaxial diamond p–n junction

Electrical properties of homoepitaxial diamond p–n⁺ junction of boron (B)-doped p-type layer and phosphorus-doped n-type layer on Ib (111) diamond single crystal have been characterized. Current–voltage characteristics show a clear rectifying property with rectification ratio of over 10⁵ at ± 10 V. From capacitance–voltage characteristics, it is found that a spatial distribution of space-charge density N_i of the p–n⁺ junction is not uniform and N_i at a middle region of the space-charge layer formed at zero bias voltage is higher than that of other region of the space-charge layer. This peculiar characteristic can be explained by superposition of two effects; one is the deep dopant effect due to B atoms in the p-type layer, which makes to reduce N_i at around the edge of the space-charge layer formed at zero bias voltage. The other is the compensation of B acceptors by impurity atoms diffusing during the p–n⁺ interface and incorporating during the growth of p-type layer, which makes to reduce N_i at the vicinity of the p–n⁺ interface.     

籼米淀粉超微粉体的制备及其性质

研究了籼米淀粉超微粉体的一种新的制备方法 ,通过正交实验确定了酶处理淀粉的最佳条件 ,考察了淀粉的溶解度和膨润力。结果表明 ,酶处理淀粉的最佳工艺参数为 :水解温度４５℃ ,时间为２５ｈ ,酶用量为水解淀粉的４５%。随着粒径的减小 ,淀粉的溶解度增大 ,膨润力下降。     

化学还原法制备纳米铜粉的研究

本文采用KBH4在液相中化学还原CuSO4,并加入KOH和络合剂EDTA ,制得了纳米级的纯净的铜粉 ,通过调整反应物的浓度 ,可以消除Cu2 O等杂质。制备的纳米铜粉还存在一定程度的团聚 ,需试验加入分散剂来改善。     

高合金钢铸造用涂料的试制与开发

介绍了炉爪用合金钢1Cr25Ni20Si2Re,导板用合金钢2Cr32Ni5采用串箱铸造过程中，有关镁砂粉涂料和石英粉涂料的试制。结果表明：镁砂粉涂料为不透气涂料，不太适用，而合理配方的石英粉涂料使用性能良好。     

超细粉碎技术现状及发展趋势

综述了国内外超细粉碎技术及设备的现状、进展,指出了其发展趋势,从工作原理、结构特点等方面详细介绍了超细粉碎典型设备,同时又指出了近年来国内外在此领域中的新进展,基于现存问题指出了今后超细粉碎研究的方向。     

Passivation effects of deuterium exposure on boron-doped CVD homoepitaxial diamond

The deuterium (hydrogen) passivation effect on acceptors in boron-doped CVD homoepitaxial diamond was studied by electrical (Hall-effect) and secondary ion mass spectroscopy (SIMS) measurements. Deuterium was incorporated into the samples using microwave (MW) deuterium plasma at 673 K for 2–24 h. We observed the progress of acceptor passivation with p-type conduction, which finally resulted in a highly resistive state.     

络合沉淀法制备BaTiO_3超细粉末

在分析ＢａＴｉＯ_３前驱体形成机理的基础上，提出了以草酸作为络合剂，用络合沉淀法制备超细ＢａＴｉＯ_３新工艺。用化学分析法测定产物Ｂａ／Ｔｉ比，用ＸＲＤ、ＴＥＭ、ＢＩ－９０激光散射粒度仪对产物的晶型、粒度及形貌进行表征。结果表明：采用该法合成的前驱体，微观组分确定，粒径小，粒度分布窄，近似球形，煅烧后为高纯超细ＢａＴｉＯ_３粉末。