材料期刊网

PRODUCTION OF HIGHLY GRAPHITIZED MULTIWALlED CARBON ANOTUBES

X.L.Zhao1) , T.L.Guo2) , M.Ohkohchi3) , T.Okazaki3) , S.Iijima and Y.Ando3) 1) Japan Science and Technology Corporation , Department of Physics , Meijo University , Shiogamaguchi1 501 , Tempaku ku , Nagoya 468 8502 , Japan 2) Scientific Research Department , Shenyang University , Wanghuanan Street21 , Dadong District , Shenyang 110044 , China 3) Department of Physics , Meijo University , Shiogamaguchi 1 501 , Tempaku ku , Nagoya 468 8502 , Japan$

金属学报(英文版)

Multiwalled carbon nanotubes ( MWNTs) were prepared by DCarc dischargein hydrogen gas, and werethermally purified byinfrared radiation in air. The morphology of pristineand purified MWNTs was observed by scanning electron microscope ( SEM) , and the crys tallinestructureand perfection wereinvestigated by high resolution transmission electron mi croscope( HRTEM) and Raman spectrometer. Itcameto the conclusion thatthese MWNTs possessed a high degreeof graphitization and very narrow centralchannel(about1 0 nm indiameter) , giving risetotheappearanceof breathing modesfor MWNTs.

关键词: multiwalled carbon nanotubes , null , null , null , null

R & D OF HYDROGEN ABSORBING ALLOYS IN JAPAN

K. Mii (Sumitomo Metal Industries , Ltd. , 1-t-3 Otemachi , Tokyo 100 , Japan)M Amano (National Research Institute for Metals , 1-2-1 Sengen , Tsukuba 305 , Japan)

金属学报(英文版)

The R & D of hydrogen absorbing alloys in Japan started in the early 1970s.Many alloys such as TiMm1.5 based alloys, Fe-Ti-O alloys (e.g. FeTi1.15 O0.024) andthe(mischmetal)Ni5 based alloys (e.g. MmNi4.5 Cr0.46 Mn0.04) were developed by the early 1980s. The application of these alloys to hydrogen storage, heat storage, heat pump, hydrogen purification and motor vehicles has been tried in many iaboratories,and the various techniques for using hydrogen absorbing alloys have been developed.The standarkization of evaluation methods for hydrogen absorbing alloys has been promoted by the Ministry of International Trade and Industry (MITI), and four of them were established as Japanese Industrial Standard (JIS).Alloys for Ni-Metal Hydride batteries have been extensively investigated since 1987in Japun. Mm-Ni-Co-Al-Mn alloys (e.g. MmNi3.55 Co0.75Al0.9Mn0.4) have been devel-oped and commereialized since 1990. The amount of production of small-size Ni-MH batteries in 1995 was about three hundred milliion in number and about one hundred billion yen. The R & D for higher enerpy-density Ni-MH batteries is intensively in progress.MITI and STA (Science and Technology Agency) have promoted the R & D of hydro-gen absorbing alloys in Japan by carrying out the national projects such as Sunshine Program (MITI: 1974-1993) and Utilization of Wind Engeray (STA 1980-1985). The New Sunshine Program (MITI 1993-2020) have started in 1993. This program con-tains the application of hydrogen absorbing alloys to Economical- Enerpy- City System and to We-NET (International Clean Energy System of Technology Utilizing Hydro-gen: World Energy Network.

关键词: hydrogen absorbing alloy , null , null , null

Sr1-x Znx Y2 S4:Er3+,Eu2+荧光粉的合成与发光特性的研究

周文理 , 朱爱玲 , 廉世勋 , 余丽萍 , 荣春英

中国稀土学报

采用碳酸盐前躯体高温分解法合成了Sr1-xZnxY2S4:Er3+, Sr1-xZnxY2S4:Eu2+和Sr1-xZnxY2S4:Er3+, Eu2+红色荧光粉. XRD图谱表明, Zn2+掺杂量x<0.2 mol 时, 粉末样品为CaFe2O4型正交晶体. Zn2+离子在Sr1-xZnxY2S4:Er3+, Eu2+中的固溶量(x mol)对荧光粉的发射强度影响很大. 随着Zn2+离子掺杂浓度的增加, Sr1-xZnxY2S4:Er3+, Eu2+(SZYSEE)紫外区激发峰(200～413 nm)发生红移, 并与可见光激发带(413～600 nm)形成一个连续的宽带谱, 与紫外和GaN基LED芯片辐射都有良好的匹配性. 当Zn2+掺杂量为0.1 mol时, SZYSEE的发光强度达到最大, 其发光强度比未掺Zn2+的增强10.7倍. Sr0.9Zn0.1Y1.76S4:0.24Er3+, 0.006Eu2+是一种潜在的白光LED用红色荧光粉.

关键词: 碱土稀土三元硫化物 , Zn2+离子 , 红色荧光粉 , 发光二极管(LED) , 稀土

Studies of the changes of Mn-Y (Y = S, Se, Te) bond lengths R with the Mn composition x in Zn1-xMnxY alloys from optical spectrum data

Journal of Physics and Chemistry of Solids

The changes of Mn-Y (Y = S, Se, Te) bond lengths R with the Mn composition x in the diluted magnetic semiconductors Zn1-xMnxY are calculated from the optical spectra and their pressure shifts. The calculated results suggest that the Mn-Y bond lengths change little with the Mn composition x-much less than expected from lattice parameters as determined by X-ray diffraction. These results are also in good agreement with the observed values obtained from the EXAFS measurements. It appears that for ternary A(1-x)M(x)Y (M denotes the divalent transition-metal ion) alloys the changes of M-Y bond lengths R with the M composition x can be studied from their optical spectrum data. (C) 2000 Elsevier Science Ltd. All rights reserved.

关键词: semiconductors;high pressure;crystal fields;luminescence;light;properties;absorption fine-structure;local-structure;dependence;pressure;exafs

Huazhong University of Science and Technology(H.U.S.T)

材料科学技术（英文）

关键词:

KⅧ-TbLⅣ离子3s3p 3P1-3s2 1S0 的自旋禁戒跃迁

牟致栋 , 魏琦瑛

原子核物理评论 doi:10.3969/j.issn.1007-4627.2004.01.015

在对KⅧ-TbLⅣ离子3s3p 3P1能级结构的多组态相互作用理论HXR方法计算的基础上, 分析了各种效应对等电子序列离子能级结构的影响, 找出了能级沿等电子序列变化的规律性. 预测计算了K Ⅷ-Tb LⅣ离子3s3p 3P1的能级. 由此进一步计算了KⅧ-TbL Ⅳ离子自旋禁戒跃迁3s3p 3P1-3s2 1S0的谱线波长、振子强度和跃迁概率.

关键词: KⅧ-TbLⅣ离子 , 自旋禁戒跃迁 , 波长 , 振子强度和跃迁概率

Corrosion of Y, Fe and Fe-15Y in H_2-H_2S Mixture under 10~(-3) Pa S_2 at 600～800℃

Yan NIU , Weitao WU and Chaoliu ZENG (State Key Lab. for Corrosion and Protection , Institute of Corrosion and Protection of Metals , Chinese Academy of Sciences , Shenyang 110015 , China)F. Gesmundo and F. Viani (Instituto di Chimica , Facolta di Ingegneria , Un

材料科学技术（英文）

The corrosion of an Fe-based alloy containing 15 wt pct Y in H2-H2S mixtures under 10-3 Pa S2 was studied at 600~800℃ in an attempt to find materials with improved sulphidation resistance with respect to pure Fe. The presence of Y has been shown to be beneflcial, but not sufficient to the level expected. In fact, the alloy is able to form at all tested temperatures an external FeS layer, beneath which a zone containing a mixture of the two sulphides is also present. Thus,Fe can still diffuse through this region to form the outer FeS layer with non-negligible rate. The corrosion rate of Fe is considerably reduced by the Y addition. but the alloy corrodes still much more rapidly than Y. The sulphidation kinetics is generally rather irregular for both the pure metals, while the corrosion rate of the alloy decreases with time and tends to become parabolic after an initial period of 12~17 h. The sulphidation behaviour of the alloys is discussed by taking into account the presence of an intermetallic compound Fe17Y2 and the limited solubility of Y in Fe

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Multiferroic phase diagram of Y partially substituted Dy(1-x)Y(x)MnO(3)

Applied Physics Letters

The effect of nonmagnetic Y partial substitution at the Dy site in Dy(1-x)Y(x)MnO(3) up to x=0.2 on magnetism, specific heat, and ferroelectricity is investigated, which resulted in a preliminary multiferroic phase diagram. It is revealed that the Y partial substitution suppresses the Dy-spin ordering point (T(Dy)) and ferroelectric ordering point (T(FE)) but enhances the Mn-spin ordering point (T(N)). The interaction between the spins of Dy and Mn is remarkably affected by Y substitution. The measured electrical polarization depends on the Y substitution in a complex way because the ferroelectricity is sensitive to the interaction between the spins of Dy and Mn. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3536506]

关键词: ferroelectricity;polarization

Corrosion of Y, Fe and Fe-15Y in H-2-H2S mixture under 10(-3) Pa S-2 at 600 similar to 800 degrees C

材料科学技术（英文）

The corrosion of an Fe-based alloy containing 15 wt pet Y in H-2-H2S mixtures under 10(-3) Pa S-2 was studied at 600 similar to 800 degrees C in an attempt to find materials with improved sulphidation resistance with respect to pure Fe. The presence of Y has been shown to be beneficial, but not sufficient to the level expected. In fact, the alloy is able to form at all tested temperatures an external FeS layer, beneath which a zone containing a mixture of the two sulphides is also present. Thus, Fe can still diffuse through this region to form the outer FeS layer with non-negligible rate. The corrosion rate of Fe is considerably reduced by the Y addition, but the alloy corrodes still much more rapidly than Y. The sulphidation kinetics is generally rather irregular for both the pure metals, while the corrosion rate of the alloy decreases with time and tends to become parabolic after an initial period of 12 similar to 17 h. The sulphidation behaviour of the alloys is discussed by taking into account the presence of an intermetallic compound Fe17Y2 and the limited solubility of Y in Fe.

关键词: high-temperature sulfidation;most-reactive component;ni-nb alloys;h2-h2s mixtures;behavior;600-degrees-c-800-degrees-c;oxidation

Optical properties of (Y1-xTmx)(3)GaO6 and subsolidus phase relation of Y2O3-Ga2O3-Tm2O3

Journal of Solid State Chemistry

A serial of samples in Y2O3-Ga2O3-Tm2O3 pseudo-ternary system are prepared by solid-state chemical reaction method. The range of solid solution in (Y1-xTmx)(3)GaO6 is 0 < x < 0.384. Powder X-ray diffraction shows that the compounds crystallize in Gd3GaO6 (Cmc2(1))-type structure. The solid solubilities of Y3+xGa5-xO12 (x = 0-0.77) and Tm3+xGa5-xO12 (x = 0-0.62) are 37.5-47.11 at% Y2O3, and 37.5-45.26 at% Tm2O3, respectively. PL spectra of Tm-doped Y3GaO6 show that there is a sharp blue emission at similar to 456 nm from the D-1(2) -> F-3(4) transition at room temperatures with two lifetimes (similar to 5 and similar to 15 mu s) and a narrow saturation range of PL intensity for the Tm3+ content from x = 0.005 to 0.03. The sharp emission and long lifetime of (Y1-xTmx)(3)GaO6 indicate that Y3GaO6 is a potential phosphor and laser crystal host material. (c) 2005 Elsevier Inc. All rights reserved.

关键词: Tm3+ -doped Y3GaO6;Y2O3-Ga2O3-Tm2O3 system;(Y1-xTmx)(3)Ga5O12 solid;solution;luminescence;crystal-structure;luminescence;phosphor;cations;ions;tb3