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Characterization of Low Pressure RF Plasma Heating

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International Journal of Minerals,Metallurgy and Materials 1998年第1期12卷 31-35页

作者： Wenxia Pan Fanxiu Lu Toyonobu Yoshida (Materials science and engineering school, {3. of science and Technology beijing, beijing 100083. china)(Department of Metallurgy, The {3. of Tokyo, Tokyo 113. Japan) Materials science and engineering school University of Science and Technology Beijing Beijing 100083 China Department of Metallurgy University of Tokyo Tokyo 113 Japan

Compacts of a-Al2O3. and Mo powder were heated in radio-frequency (RF) induced low pressure N2, H2,Ar, and their mixture plasma. An optical pyrometer, a radiation pyrometer, and a system called Accufiber Model3.0 were used to measure the temperature of compacts heated in the plasma. The results indicate that there are different heat transfer mechanisms from plasma to specimens of different physical properties. The Ar plasma showed thehighest heating ability among N2, H2, and Ar plasma for Al2O3.specimens, whereas the H2 plasma could heat Mospecimens to a higher temperature than the Ar plasma did, even under the same generating conditions.

关键词： plasma heating temperature measurement heat transfer mechanism

Aspects of microstructure in low carbon steels produced by the CSP process

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Journal of university of science and Technology beijing 2003年第4期10卷 1-6页

作者： Delu Liu, Xiangdong Huo, Yuanli Wang, and Xianwen SunMaterials science and engineering school, {3. of science and Technology beijing, beijing 100083. china Materials science and engineering school University of Science and Technology Beijing Beijing 100083 China (Received 2003-05-20)

The solidification structure, microstructure evolution during rolling andprecipitates with nanometers in dimension of the low carbon steels produced by CSP process with thinslabs have been studied in recent years. Important differences in microstructure and mechanicalproperties between the CSP products and the conventional one were observed. These differences mayarise from the much rapider solidification rate and cooling rate after casting of the thin *** aspects of the microstructure for the low carbon steels of the CSP thin slabs are summarizedand compared with the conventional one.

关键词： low carbon steel CSP hot strip microstructure evolution grain refinement

High Resolution Electron Microscopy Observations of Structural Changes in Iron Nitride Films Annealed in Vacuum

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Journal of Materials science & Technology 1997年第2期13卷 123-126页

作者： Shengkai GONG Huibin XU (Dept. of Materials science and engineering, beijing {3. of Aeronautics and Astronautics, beijing 100083. china) Dept. of Materials science and engineering Beijing University of Aeronautics and Astronautics Beijing 100083 China

Iron-nitride films were prepared by reactive sputtering, and the effect of annealing treatment on the structures was investigated by means of in-situ electron microscopy and high resolution electron microscopy (HREM). As-deposited films were observed to be a mixed structure of a few ultrafine epsilon-Fe2-3. particles existing in the amorphous matrix. it was found that the structure-relaxation in the amorphous occurred at 473.K, and the ultrafine grains began to grow at the higher annealing temperatures. The transition of the amorphous to epsilon-Fe2-3. was almost completed at 673.K. It is considered that the formation of the ideal epsilon-Fe3. is originated from the ordering of the nitrogen atoms during the annealing in vacuum. On the other hand, gamma'-phase (Fe4N) was seen to precipitation of epsilon-phase at 723.K. Two possible modes are proposed in the precipitation of gamma'-phase, depending on the heating rate and crystallographic orientation relationships, i.e. [121](epsilon)//[001](gamma), (2(1) over bar0$)(epsilon)//(110)(gamma) and [100](epsilon)//[110](gamma), (001)(epsilon)//(111)(gamma). In addition, alpha-Fe particles were observed to form from the gamma'-phase at high temperatures. We assumed that these structural changes are due to the diffusion of nitrogen and iron atoms during the annealing, except for the case of the precipitation of the gamma'-phase as depicted above. The results obtained in this work are in a good agreement with the assumption.

关键词： Figure High Resolution Electron Microscopy Observations of Structural Changes in Iron Nitride Films Annealed in Vacuum

Transformation Behaviour of Austenite in Steel under Condition of Stress-strain and Its Application

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Journal of Materials science & Technology 1995年第6期11卷 440-442页

作者： Xu WANG Sigen WANG and Lixian HUA (Dept. of Materials science and engineering, university of science and Technology beijing, beijing, 100083. china) beijing Univ of science and Technology Beijing China

Austenite can be retained at ambient temperature in steels by alloying and processing control. The transformation from austenite to martensite occurs under a certain conditions : thermal or deformation. Stress-strain induced martensitic transformation is important to improve the plasticity of steels which is called transformation induced plasticity (TRIP). Strength-ductility balance of the steels is greatly superior to that of other high strength steels due to the TRIP effect. A new type of steels-TRIP steel is developed

关键词： TRIP Transformation Behaviour of Austenite in Steel under Condition of Stress-strain and Its Application

Hot Corrosion of Iron in the Presence of Salt Mixture Deposit Containing NaCl and V_2O_5 at 600℃

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Journal of Materials science & Technology 1996年第6期12卷 445-451页

作者： Lingchuan LI (Dept. of Materials science and engineering, Tsinghua university {3. 100084, china)Rizhang ZHU (Dept. of Surface science and Corrosion engineering, university of science and Technology {3., beijing 100083. china)(To whom correspondenc Dept. of Materials science and engineering Tsinghua University Beijing 100084 China Dept. of Surface science and Corrosion engineering University of Science and Technology Beijing Beijing 100083 China Instiuto di Chimica Facolta di Ingegneria Università di Genova Fiera del Mare Pad.D 16129 Genova Italy

Iron suffered low temperature hot corrosion (LTHC) in the presence of salt deposits of Na2SO4,Na2SO4 mixed with NaCl and Na2SO4 mixed with V2O5 in a combustion gas at 600℃. The additions of NaCl to Na2SO4 and of V2O5 to Na2SO4 changed the corrosion kinetics significantly and modified the scale structure markedly It is proposed that trivalent iron ions were more favored than divalent ions in the eutectic responsible for the occurrence of LTHC when NaCl was present, while the reaction between Na2SO4 mixed with V2O5 and the gas formed (Na2O)xV2O4(V2O5)6-x providing directly the liquid required by LTHC. The suphide formation in the inner FeO larer was related to the sites of the reduction step wher SO2 was released.

关键词： SO NaCl

Probability parametric imaging with DCE-MRI data to identify prostate cancer in the peripheral zone

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Progress in Natural science:Materials International 2006年第9期16卷 948-953页

作者： HUANG Xinrui, WANG Qiang, XU Yufeng, WANG Xiaoying and BAO Shanglian ( The Key Laboratory of Medical Physics and engineering, Peking university, {3. 100871, china The Medical school of Peking university, beijing 100083. china 3. The First Hospital of Peking university, {3. 10003., china) [a]The key Laboratory of Medical Physics and engineering Peking University Beijing China [b]The Medical school of Peking university Beijing China [c]The First Hospital of Peking university Beijing China

To quantitatively analyze prostate dynamic contrast-enhanced magnetic resonance images (DCE-MRI), a retrospective study was carried out to construct a mathematical model to predict whether a lesion is cancerous or not. With known diagnosis of 52 re-gions-of-interest (10 malignant, 26 benign and 16 normal) in peripheral zone (PZ) of prostate from 18 patients undergoing needle biopsy and 8 normal volunteers, we combined feature parameters (k1, k2 and tp) from the linear-slope model with logistic regression to determine the statistical probability model. Prostate cancerous probability maps were derived using the model on each subject to examine the correlation between the model-based prediction and the known diagnosis. Compared the model prediction results of 52 regions-of-interest with the histopathologic results, the total agreement rate was 90.4 % ; the agreement rate was 60 % for the malignant and 97. 6 % for the nonmalignant. The diagnostic results only referencing the probability maps by two radiologists showed a high agreement in tissue characteristics and lesion location with the combining results from other diagnostic techniques such as PSA (prostate specific antigen) level and MRS (magnetic resonance spectroscopy) .

关键词： time-intensity curve prostate DCE-MRI logistic regression probability parametric image.

Corrosion Fatigue Behavior of Duplex Stainless Steel in 3.5% Sodium Chloride Solution

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Journal of university of science and Technology beijing 2001年第2期8卷 133-136页

作者： S. H Abubakir, Yinshun Wu, Baofeng Ding, Jiuqing Li Bei Cao (Material science and engineering school, {3. of science and Technology beijing, beijing 100083. china) Univ Sci & Technol beijing Mat Sci & Engn Sch Beijing 100083 Peoples R China

The corrosion fatigue behavior of duplex stainless steel (DSS) was studied at different cyclic stress levels in 3.5%NaCl (mass fraction, so as the follows) solution (pH=7) at 50 degreesC. The results showed that DSS was susceptible to pitting corrosion and corrosion fatigue. Both intergranluar corrosion cracking and transgranlular corrosion cracking initiated at the bottom of pitting holes. Furthermore, the corrosion fatigue properties of DSS in 3.5%NaCl solution may be relatived to complex electrochemical and mechanical coupling effects between the three phases (austenite, ferrite and martensite), where martensite and ferrite were anodic in the corrosion cell and could be prone to cracking under certain condition.

关键词： corrosion fatigue duplex stainless steel sodium chloride solution

Research of MPLS traffic engineering over differentiated services

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Journal of university of science and Technology beijing 2002年第6期9卷 474-477页

作者： Yang Hu, Yang Yang, and Weidong HaoInformation engineering school, university of {3. and Technology beijing, beijing 100083. china Information engineering school University of Science and Technology Beijing Beijing 100083 China

An approach to traffic engineering that uses differentiated services (DS) andmulti-protocol label switching (MPLS) to provide quantitative network quality of service (QoS)guarantees over an IP network was proposed. The traffic associated with assured forwarding (AF)Per-Hop behavior (PHB) in differentiated services enabled IP network was modeled. Furthermore, theeffect of such traffic on network resources with die objective of developing efficient trafficengineering methodologies was analyzed and the optimization problem relating to traffic engineeringin DS networks with an MPLS core was formulated. The service received by TCP and UDP flows when theyshare either a link or a MPLS traffic trunk was also compared and found that in order to benefitfrom traffic engineering, MPLS trunks should be implemented end-end (first router to last router).If some part of the network is MPLS trunk-unaware, the benefits are reduced or eliminated.

关键词： MPLS differentiated services QoS traffic engineering

GTA Welds of Iron-Aluminide Based Alloys

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Journal of university of science and Technology beijing 2001年第1期8卷 39-42页

作者： Dechun Gao, Wangyue Yang, Min Dong, Jihua Huang, Yuanding Huang, Zuqing Sun Material science and engineering school, {3. of science and Technology beijing, beijing 100083. china Univ Sci & Technol beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China

The weldability of two Fe3.l-based intermetallic alloys and one Fe-16%Al-based (atom fraction) alloy has been investigated for gas tungsten are (GTA) welding on sheets with a thickness of 2 mm. The results indicated that pre-heating and post-annealing treatment were important procedures for retarding cold crack initiation and the propel selection of filler could effectively improve the weldability. For the same alloys with the same welding filler, it is better to choose lower welding current, in another word, lower heat input.

关键词： iron-aluminide gas tungsten arc welding weldability filler