检索结果-南通市图书馆

Phase transformation of nano-grained W(Co, C) composite powder and its phase constitute

在线全文

学校读者我要写书评

暂无评论

中南工业大学学报：英文版 2006年第6期13卷 603-607页

作者：曹顺华蔡志勇周建华李炯义林信平 State Key laboratory of Powder Metallurgy Central South University

A new process of WC-Co cemented carbide was developed by using nano-grained W(Co, C) composite powders as raw materials processed by high-energy ball milling. x-ray diffraction(xRD), differential thermal analysis (DTA), thermo-gravimetric (TG) analysis and coercive forces of the sintered samples were adopted to analyze the phase transformation and constitution, and the microstructures of sintered samples were characterized by scanning electron microscopy(SEM). The results show that the as-milled powders are transformed into transitional phases W2C and η (Co3W3C or Co6W6C) during sintering, and finally transformed into WC and Co phases completely at 1 250 ℃ for 30 min, and a large number of fibrous WC grains with about 1.2 μm in length and 100 nm in radial dimension are formed in the sintered body at 1 300 ℃.

关键词：硬质合金粉末纳米粒级W(Co,C)复合粉末相变碳化物高能球磨

Synthesis and Structural Characterization of a New 1D Polymeric Energetic Complex [Hg(DAT)Cl_2]_n (DAT = 1,5-Diaminotetrazole)

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2013年第5期32卷 653-658页

作者：李志敏张建国杨威孙谋张同来 State Key laboratory of Explosion Science and Technology Beijing Institute of Technology

A new energetic complex [Hg（DAT）Cl2]n was synthesized by the reaction of 1,5-diaminotetrazole with mercury bichloride and characterized by elemental analysis, IR spectroscopy and x-ray single-crystal diffraction. The crystal belongs to the monoclinic system with P21/c space group, and a = 4.0342（3）, b = 17.7999（12）, c = 10.0127（7） , β = 91.558（1）°, V = 718.73（9） 3, Z = 4, CH4Cl2HgN6, Mr = 371.59, Dc = 3.434 g·cm-3, F（000） = 664, S = 1.037, the final R = 0.0223 and wR = 0.0642 for 1646 observed reflections with Ⅰ 〉 2σ（Ⅰ）. The central Hg is coordinated by one N atom from 1,5-diaminotetrazole and one mono-dentate terminal chloride and two bi-dentate bridging chloride ligands. Adjacent Hg cations were connected by the bi-dentate Cl to form a 1D zigzag supramolecular chain along the a-axis.

关键词： energetic materials mercury complex 1,5-diaminotetrazole crystal structure

Effects of Ⅴ/Ⅲ ratio on species diffusion anisotropy inthe MOCVD growth of non-polar a-plane GaN films

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2010年第1期19卷 520-523页

作者：赵璐冰于彤军吴洁君杨志坚张国义 research Center for Wide Gap Semiconductors Peking UniversityState Key Laboratory for Artificial Microstructure and Microscopic PhysicsSchool of PhysicsPeking University

Non-polar a-plane （1120） GaN films have been grown on r-plane （1102） sapphire substrates by metal organic chemical vapour deposition. The influences of V/III ratio on the species diffusion anisotropy of a-plane GaN films were investigated by scanning electron microscopy, cathodoluminescence and high-resolution x-ray diffraction measurements. The anisotropy of a-plane GaN films may result from the different migration length of adatoms along two in-plane directions. V/III ratio has an effect on the growth rates of different facets and crystal quality. The stripe feature morphology was obviously observed in the film with a high V/III ratio because of the slow growth rate along the [1100] direction. When the V/III ratio increased from 1000 to 6000, the in-plane crystal quality anisotropy was decreased due to the weakened predominance in migration length of gallium adatoms.

关键词： non-polar GaN V/III ratio anisotropy migration length

早期乳腺癌保乳术后部分乳腺高剂量率后装加速照射的毒性反应及美容效果

在线全文

学校读者我要写书评

暂无评论

中华放射肿瘤学杂志 2007年第1期16卷 25-29页

作者：修霞 Tripuraneni Prabhakar Giap Huan Lin ray Chu Colin 北京医院放疗科 100730 Tripuraneni Prabhakar Giap HuanLin RayChu Colin

目的介绍早期乳腺癌保乳术后单独行局部高剂量率组织间插植加速照射的方法、副作用及美容效果。方法46例Ⅰ、Ⅱ期乳腺癌的47个乳腺在肿瘤局部扩大切除后使用了高剂量率^192Ir组织间插植瘤床区加速照射（APBI）。符合条件的患者包括年龄... 详细信息

目的介绍早期乳腺癌保乳术后单独行局部高剂量率组织间插植加速照射的方法、副作用及美容效果。方法46例Ⅰ、Ⅱ期乳腺癌的47个乳腺在肿瘤局部扩大切除后使用了高剂量率^192Ir组织间插植瘤床区加速照射（APBI）。符合条件的患者包括年龄＞40岁、T1～T2N0～N1（≤3阳性淋巴结），手术切缘＞1～2mm，小叶癌和炎性乳腺癌除外。术后接受高剂量率近距离放疗，2次／d，间隔至少6h，总量34Gy分10次5d完成。治疗后1、6、12个月及以上观察毒性反应及美容效果。结果全组患者随访18～46个月（中位随访34个月），治疗期间急性反应包括红斑、水肿、乳腺触痛和感染共21例（46％），均为1～2级，无3～4级发生。晚期毒性包括皮肤纤维化、乳腺触痛、脂肪坏死及毛细血管扩张1＋2级加例（43％），3级2例（4％），其中1例疗后接受6个周期系统化疗。美容效果达到极好和良好的在6、12个月分别为95％、98％，无一局部复发。结论早期乳腺癌保乳术后APBI后装组织间插植技术具有良好美容功效，急性和晚期毒性作用小，局部控制率有待于长期随访观察。

关键词：乳腺肿瘤/放射疗法近距离疗法毒性反应美容效果

Approaches to eliminate near field artifact of MURA

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2008年第1期32卷 80-82页

作者：王人松戎军艳魏龙 Key laboratory of Nuclear Analysis Techniques Institute of High Energy Physics CAS

Since the coded aperture technique has been successfully applied on x-ray imaging space telescopes, attentions of its development have also been cast on the application in medical imaging, for it has a very tempting quality to greatly enhance the detection sensitivity without gravely lowering the spacial resolution. But when the coded aperture technique is applied to image a nearby object, the so called ＂near-field artifact＂ comes up, that is, the reconstructed image has a sort of distortion. Among types of coded apertures the MURA （Modified Uniformly Redundant Array） is one of the most discussed. Roberto Arrcosi came up with the solution to remove the artifacts utilizing mask and antimask. In this article we present two ways to eliminate the second order aberration based on his work.

关键词： MURA coded aperture MLEM optical supplementary principle

Synthesis and Crystal Structure of a Ternary Complex:[Ni(phen)_2(pmal)]·8H_2O

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2006年第10期25卷 1265-1269页

作者： SNN Ya-Guang laboratory of Coordination Chemistry Shenyang Institute of Chemical TechnologyShenyang 110142 China

A new ternary complex [Ni（phen）（pmal）]·8H2O （phen = 1,10-phenanthroline, pmal^2- = phenethyl malonic acid） has been synthesized by the reaction of nickel acetate, phen and phenethyl malonic acid. Elemental analysis, IR spectra and x-ray single-crystal diffraction were carried out to determine the composition and crystal structure. Crystal data for this complex： triclinic system, space group PI^-, a = 10.387（5）, b = 13.112（6）, c = 14.229（6） °A, α= 76.176（7）, β = 83.778（8）, γ = 71.770（6）°, C35H42N4O12Ni, Mr= 769.44, Z = 2, F（000） = 808, V = 1786.1°A^3, Dc = 1.431 g/cm^3,μ= 0.612 mm^-1, the final R = 0.0653 and wR = 0.1033 for 9379 （Rint = 0.0244） independent reflections and 4730 observed reflections （I〉 2σ（I））. Structural analysis shows that the coordination geometry of Ni（Ⅱ） is a distorted octahedron. A novel two-dimensional structure is constructed from （H2O）4 and （H2O）12 water clusters, and the complex forms a 3-D network supramolecular structure by hydrogen bonds and π-π stacking of neighboring phens.

关键词： Ni(Ⅱ) phenethyl malonic acid crystal structure water cluster

Effect of Cu Content on Aging Precipitation Behaviors of Cu-Rich Phase in Fe-Cr-Ni Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel research(International) 2010年第5期17卷 63-68页

作者： TAN Shu-ping WANG Zhen-hua CHENG Shi-chang LIU Zheng-dong HAN Jie-cai FU Wan-tang School of Astronautics Harbin Institute of Technology Harbin 150001 Heilongjiang China State Key laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao 066004 Hebei China Central Iron and Steel research Institute Beijing 100081 China

The precipitation characteristics and effect on strengthening mechanism of Cu-rich phases during short-time and long-time aging for Super 304H steels with different Cu content were investigated using x-ray diffraction （xRD）, scanning electron microscope （SEM） and transmission electron microscope （TEM）. The results show that the size of Cu-rich phase particles increases, the interspace of Cu-rich phase particles decreases and the density of Curich phases increases with the increase of Cu content during short-time aging （approximately 800 h） at 650℃ for Super 304H steels. During long-time aging （more than 2 000 h） at 650 ℃, Cu-rich phase precipitates sufficiently and the strengthening effect of Cu-rich phase is preferable in Super 304H steel containing Cu of 4%. The strengthening effect of Cu-rich phase in Super 304H steels containing Cu of 2.2% or 5% is weaker than that with Cu of 4% during long-time aging （more than 2 000 h）.

关键词： heat resistant alloy Cu content Cu-rich phase aging precipitation strengthening

Low-Angle Grain Boundaries in Sublimation Grown 6H-SiC Crystals

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2006年第Z1期24卷 8-10页

作者： Jiang Shouzhen Li xianxiang Dong Jie Chen xiufang xu xiangang Hu xiaobo State Key laboratory of Crystal Materials Shandong UniversityJinan 250100China

High-resolution x-ray diffractometry(HRxRD)was used to assess the quality of 6H-SiC crystals grown by sublimation *** results show the occurrence of low-angle grain boundaries(LB)is close relative to the inclination of the crystal *** the central faceted region with 0°inclination the crystal is of high structural ***,at the region close to the facet with less than 5°inclination LB occurs slightly and at the region close to the peripheral polytype ring with more than 5°inclination LB defect occurs *** density of LB can be drastically reduced by decreasing radial temperature gradient that determines the shape of the crystal growth interface.

关键词： low-angle grain boundaries sublimation 6H-SiC radial temperature gradient

Synthesis, Crystal Structure and Spectroscopic Properties of Cyanide-bridged Complex [RuⅡ（ttpy）（CN）3MnⅢ（salen）]

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2019年第5期38卷 745-753,669页

作者：孙桂芳栗佳琪余洪亮于孟彭佩丁文文王勇 Hubei Key laboratory of Drug Synthesis and Optimization Jingchu University of Technology

Tricyanide building block K[Ru(ttpy)(CN)3] and [MnⅢ(salen)](ClO4) have been used to design and synthesize a heterobimetallic one-dimensional(1D) zigzag chain complex 1,[RuⅡ(ttpy)(CN)3 MnⅢ(salen)](ttpy = 4′-(p-tolyl)-2,2′:6′,2″-terpyridine, salen = N,N?-ethylenebis-(salicylideneaminato)dianion). Single-crystal x-ray diffraction analysis shows complex 1 crystallizes in orthorhombic Pbca space group and the asymmetric unit of 1 contains one[-NC-RuⅡ(ttpy)(CN)(m-CN)-Mn Ⅲ-(salen)-] molecule. In the structure of 1, each [Ru Ⅱ(ttpy)(CN)3]-connects two [MnⅢ(salen)]+ with two cyanide groups in a cis-conformation, and in turn each[MnⅢ(salen)]+ unit links two [RuⅡ(ttpy)(CN)3]-building blocks in a trans-conformation, resulting in a 1D [-NC-RuⅡ-CN-MnⅢ-]n chain. Furthermore, the electronic absorption spectra and luminescence spectroscopy of complex 1 have also been studied.

关键词： cyanide-bridged crystal structure Ru(Ⅱ) spectroscopic properties Mn(Ⅲ)