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FAILURES AND THE LIFE OF FURNACE TUbES

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Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 419-425页

作者： F.z.Shen y.Ding D.M.Hou z.p.Ning y.Lü T.b.Dong A.R.Tuohuti Nanjing University of Technology Nanjing 210009 ChinaNanjing University of Technology Nanjing 210009 ChinaLutianhua Group Incorporated Luzhou 646300 ChinaLutianhua Group Incorporated Luzhou 646300 ChinaLutianhua Group Incorporated Luzhou 646300 ChinaSouthwestern Tarim Exploration & Development Company Zepu 844804 ChinaSouthwestern Tarim Exploration & Development Company Zepu 844804 China

It is showed after the furnace tubes serviced for 8-10 years that the density of damage in the HAz (heat affected zone) of the weld has higher than in parent metals, though the depth of damage is not equal to. by the test of creep crack growth, it is also acquired that under same mechanic parameter C* (t), the rate of creep crack growth in the HAz is more than twice as fast as in parent metals. Two mechanisms (overheating and thermal shock) of failure occurred in an accident are presented. The stress of thermal shock is analyzed, in which the change of the elasticity modulus with the radius ET = /(r) is considered. based on it, the safety region of the thermal shock is obtained. Finally, two sets of curves for the safe life are suggested which can facilitate to estimate the remaining life of HK-40 or Hp-Nb tubes by their creep rupture data.

关键词： failure thermal stock creep crack growth remaining life furnace tube

photoinitiated Reaction of β-bromonaphthalene with pinacolone Ion in DMSO

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Chinese Chemical Letters 2000年第11期11卷 945-948页

作者： Chen z.b. zhao L.y. zhang z. Department of Chemistry University of Shanxi Taiyuan Shanxi 030006 China

The photoinitiated reaction of β-bromonaphthalene with excess pinacolone enolate does not yield expected normal SRN1 product 1-β-naphthyl-3,3-dimethyl-2-butanone, 3, but a more complex molecule 2,2-dimethyl-5-(1',1'-dimethylethyl)-6-β-naphthyl-5-hexene-3-one, 4, deriving from it. The reaction is inhibited by m-dinitrobenzene and do not occur in the absence of light. Structure analysis of the product, along with other evidence, indicates a mechanism for this reaction, where addition of a further pinacolone molecule to carbonyl group of 3 and subsequent elimination of a water molecule would afford product 4, once the SRN1 substitution product 3 has formed.

关键词： photoinitiated Reaction of MS bromonaphthalene with pinacolone Ion in DMSO

Evolution of the Microstructure and Strength in the Nugget zone of Friction Stir Welded SiCp/Al-Cu-Mg Composite

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Journal of Materials Science & Technology 2014年第1期30卷 54-60页

作者： D.Wang b.L.Xiao Q.z.Wang z.y.Ma Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences University of Science and Technology of China

A 6 mm-thick SiCp/2009AI composite plate was successfully joined by friction stir welding （FSW） using an ultrahard material tool to investigate the evolution of the microstructure and the strength in the nugget zone （Nz）. While some SiC particles were broken up during FSW, most of them rotated in the matrix. Large compound particles on the interfaces were broken off during FSW, whereas the amorphous layer and small compound particles remained on the interfaces. The dynamically recrystallized AI grains nucleated on the surface of fractured SiC particles during FSW, forming nano-sized grains around the SiC particles. The yield strength of the Nz decreased slightly due to the variation in the size, shape, and distribution of the SiC particles. The clean interfaces were beneficial to the load transfer between SiC particles and AI matrix and then increased the ultimate tensile strength of the Nz.

关键词： Metal-matrix composites Friction stir welding Microstructure Mechanical properties

Depsides from prunella vulgaris

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Chinese Chemical Letters 2000年第11期11卷 997-1000页

作者： Wang z.J. zhao y.y. Wang b. Ai T.M. Chen y.y. Department of Natural Medicines Beijing Medical University Beijing 100083 China

A novel depsides 1, together with three known ones 2-4 and two phenylpropanoids 5-6 were isolated from the ethanol extract of the spikes of prunella vulgaris. On the basis of spectral and chemical evidence, their structures were deternined as butyl rosmarinate 1, ethyl rosmarinate 2, methyl rosmarinate 3, rosmarinic acid 4, 3,4,α-trihydroxy-methyl phenylpropionate 5 and p-coumaric acid 6, respectively.

关键词： MS acid Wang DMSO 亚砜 FAb

Effect of Nitrogen Content on Microstructures and Mechanical properties of Wb_2(N) Films Deposited by Reactive Magnetron Sputtering

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Journal of Materials Science & Technology 2015年第12期31卷 1217-1225页

作者： y.M.Liu D.y.Deng H.Lei z.L.pei C.L.Jiang C.Sun J.Gong Institute of Metal Research Chinese Academy of Sciences

In the present study,Wb 2（N） films are fabricated on silicon and yG8 substrates at different N 2 pressures by reactive magnetron *** influence of N 2 partial pressure（p （N2）） on the film microstructure and characteristics is studied systematically,including the chemical composition,crystalline structure,residual stress,surface roughness as well as the surface and the cross-section ***,nano-indentation and ball-on-disk tribometer are performed to analyze the mechanical and tribological properties of the *** results show that the addition of nitrogen apparently leads to the change of the structure from（1 0 1） to（0 0 1） orientation then to the amorphous structure with the formation of bN *** the addition of nitrogen can greatly refine the grain size and microstructure of the ***,the residual stress of the film is also found to change from tensile to compressive stress as a function of p （N2）,and the compressive stress increases with p （N2）,The Wb 2（N） films with small nitrogen content,which are deposited at p （N2） of 0.004 and 0.006 pa,exhibit better mechanical,tribological and corrosion properties than those of other *** increase of nitrogen content accelerates the formation of bN phase and fast decreases the film *** addition,the large N 2 partial pressure gives rise to the target poisoning accompanied by the increase of the target voltage and the decrease of the deposition rate.

关键词： Reactive magnetron sputtering Nanocomposites Wb 2(N) films Residual stress Mechanical properties

First principles calculations on the thermoelectric properties of bulk Au2S with ultra-low lattice thermal conductivity

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Chinese physics b 2020年第8期29卷 108-114页

作者： y y Wu X L zhu H y yang z G Wang y H Li b T Wang School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China Institute of High Energy physics Chinese Academy of SciencesBeijing 100049China Spallation Neutron Source Science Center Dongguan 523808China School of Materials Science and Engineering Hunan University of Science and TechnologyXiangtan 411201China Institute of Modern physics Chinese Academy of SciencesLanzhou 730000China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China

Sulfide nanocrystals and their composites have shown great potential in the thermoelectric(TE)field due to their extremely low thermal *** a solid and hollow metastable Au2S nanocrystalline has been successfully ***,we study the TE properties of this bulk Au2S by first-principles calculations and semiclassical boltzmann transport theory,which provides the basis for its further experimental *** results indicate that the highly twofold degeneracy of the bands appears at theΓpoint in the brillouin zone,resulting in a high Seebeck ***,Au2S exhibits an ultra-low lattice thermal conductivity(~0.88 W·m^-1·K^-1 at 700 K).At 700 K,the thermoelectric figure of merit of the optimal p-type doping is close to 1.76,which is higher than 0.8 of zrSb at 700 K and 1.4 of ptTe at 750 *** work clearly demonstrates the advantages of Au2S as a TE material and would greatly inspire further experimental studies and verifications.

关键词： first principles calculation thermodynamic transport properties

Crack Initiation Mechanism of z3CN20.09M Duplex Stainless Steel during Corrosion Fatigue in Water and Air at 290 °C

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Journal of Materials Science & Technology 2015年第11期31卷 1144-1150页

作者： H.C.Wu b.yang y.z.Shi Q.Gao y.Q.Wang State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Collaborative Innovation Center of Universal Iron & Steel Technology School of Materials Science and Engineering Anhui University of Technology

The crack initiation mechanism of a z3CN20.09M duplex stainless steel （DSS） during corrosion fatigue （CF） in water and air at 290 ℃ was investigated by using a CF cracking machine and a scanning electron microscopy （SEM）. The cracks were initiated successively at the persistent stip bands （pSbs）, phase boundaries （pbs） and pitting corrosion points （pCps） of the specimens when they were tested in water at 290 ℃, while in airat 290 ℃ the cracks were only initiated at the pSbs and pbs. And the cracks were found mainly to initiate at the pSbs and pbs when the specimens were tested in water and air at 290 ℃, respectively. The results also reveal that the cracks were likely to be initiated at the first 20% of fatigue life of the specimens tested in water at 290 ℃. However, the cracks were not found until 50% of fatigue life when tested in air at 290 ℃. Moreover, the crack numbers of the specimens tested in water at 290 ℃ were much more than those tested in air at 290 ℃.

关键词： Duplex stainless steel Corrosion fatigue Crack initiation High temperature water

基于状态空间模型的激光再制造熔池温度控制系统

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表面工程与再制造 2024年第2期24卷 50-50页

作者： yang G.-z. Liu T.-M. Song b.-X. Jiang X.-y. Wang z.-S. Chen K.-Q. Liu W.-J. School of Mechanical Engineering Shenyang University of Technology Shenyang China

激光再制造是用于再制造的一项重要技术,在航空航天、冶金、能源等领域应用广泛。然而,形状控制问题一直是制约其规模化和工业化应用的瓶颈。在激光再制造过程中,熔池温度是决定再制造件形状和性能稳定性的关键。基于此,本文提出了一种... 详细信息

激光再制造是用于再制造的一项重要技术,在航空航天、冶金、能源等领域应用广泛。然而,形状控制问题一直是制约其规模化和工业化应用的瓶颈。在激光再制造过程中,熔池温度是决定再制造件形状和性能稳定性的关键。基于此,本文提出了一种基于状态空间模型的激光再制造熔池温度实时在线控制方法,解决了控制机理模型难以建立和多变量约束的问题。

关键词：状态空间模型激光再制造熔池温度航空航天形状控制控制系统变量约束性能稳定性

Giant magnetocaloric effect in the Gd_5 Ge_(2.025)Si_(1.925)In_(0.05) compound

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Chinese physics b 2010年第3期19卷 517-522页

作者： E.yzak I.Dincer y.Elerman Department of Engineering physics Faculty of EngineeringAnkara University06100 BesevlerAnkaraTurkey

The magnetocaloric properties of the GdsGe2.025Si1.925In0.05 compound have been studied by x-ray diffraction, magnetic and heat capacity measurements. powder x-ray diffraction measurement shows that the compound has a dominant phase of monoclinic Cd5Ge2Si2-type structure and a small quantity of Gds（Ge,Si）3-type phase at room temperature. At about 270 K, this compound shows a first order phase transition. The isothermal magnetic entropy change （△SM） is calculated from the temperature and magnetic field dependences of the magnetization and the temperature dependence of MCE in terms of adiabatic temperature change （△Tad） is calculated from the isothermal magnetic entropy change and the temperature variation in zero-field heat-capacity data. The maximum △SM is -13.6 J·kg^-1.K^- 1 and maximum ATad is 13 K for the magnetic field change of 0 5 T. The Debye temperature （θD） of this compound is 149 K and the value of DOS at the Fermi level is 1.6 states/*** from the low temperature zero-field heat-capacity data. A considerable isothermal magnetic entropy change and adiabatic temperature change under a field change of 0-5 T jointly make the Gd5Ge2.025Si1.925In0.05 compound an attractive candidate for a magnetic refrigerant.

关键词： magnetic properties magnetocaloric effect isothermal magnetic entropy change adia-batic temperature change