刘守平
,
周上祺
,
王佳眉
,
任勤
腐蚀科学与防护技术
用金相显微镜、扫描电镜、X射线衍射仪和X射线能谱仪对天然气井油管悬挂器腐蚀失效进行了检测分析，并对天然气井油管悬挂器用35CrMo钢进行了盐雾试验，结果表明，天然气中的水和CO2是引起腐蚀的主要介质，腐蚀产物主要是FeCO3，高速天然气冲刷和钢中的非金属夹杂加剧了腐蚀的速度.
CORROSION FAILURE ANALYSIS OF AN OIL TUBE USED IN NATURAL GAS WELL
LIU Shou-ping,ZHOU Shang-qi,WANG Jia-mei,REN Qin
Chongqing University
A failed oil tube used in natural gas well was examined by optical microscope,scanning electron microscope ,X-ray diffractometer and X-ray spectrometer.Corrosion behavior of 35CrMo steel samples of the oil tube were investigated by means of salt spray tests in the laboratory.The results show that CO2 and H2O are primary factors in the corrosion of oil tube.The corrosion product is FeCO3,non-metallic inclusions in the steel and erosion of natural gas fluid played an important role in accelerating the corrosion.
oil tube;
natural gas well；
35CrMo steel；
failure analysis；
corrosion
关键词:
悬挂器
,
null
,
null
,
null
Physical Review B
In order to understand the unusually large value of zero-field splitting D for the axial Fe3+ center in a KTaO3 crystal, Zhou made two assumptions in his recent report [Phys. Rev. B 42, 917 (1990)]. In this Comment we will show that his assumption II is qualitatively reasonable, whereas assumption I is unnecessary and doubtful.
关键词:
electric-field;srcl2
Journal of Physics and Chemistry of Solids
The layered ternary ceramics Ti3SiC2 and Ti3AlC2 are isostructural and can form Ti3Si1-xAlxC2 solid solutions combining the advanced properties of both compounds [H.B. Zhang, Y.C. Zhou, Y.W. Bao, M.S. Li, Improving the oxidation resistance of Ti3SiC2 by forming a Ti3Si0.90Al0.1C2 solid solution, Acta Mater. 52 (2004) 3631-3637; E.D. Wu, J.Y. Wang, H.B. Zhang, Y.C. Zhou, K. Sun, Y.J. Xue, Neutron diffraction studies of Ti3Si0.9Al0.1C2 compound, Mater. Lett. 59 (2005) 2715-2719; J.Y. Wang, Y.C. Zhou, First-principles study of equilibrium properties and electronic structure of Ti3Si0.75Al0.25C2 solid solution, J. Phys.: Condens. Matter 15 (2003) 5959-5968; Y.C. Zhou, J.X. Chen, J.Y. Wang, Strengthening of Ti3AlC2 by incorporation of Si to form Ti3Al1-xSixC2 solid solutions, Acta. Mater. 54 (2006) 1317-1322]. In the present work, the solid solutions of Ti3Si1-xAlxC2 (x = 0, 0.25, 0.33, 0.5, 0.67, 0.75, 1) are investigated by first-principle calculations based on pseudo-potential plan-wave method within the density functional theory framework. The results show that as Al content increases in the solid solution, all the bonds have weakened to certain extents, which lead to an unstable structure both energetically and geometrically. The calculated results are compared and discussed with the reported data for the Ti3Si1-xAlxC2 solid solutions. (c) 2007 Elsevier Ltd. All rights reserved.
关键词:
ceramics;ab initio calculations;electronic structure;electrical;conductivity;oxidation behavior;mechanical-properties;ti3sic2;temperature;ti3alc2;air;si
Journal of Physics-Condensed Matter
This research purposes to investigate the atomic and electronic structures of the Al/TiC(001) interface with lattice misfit using the ab initio pseudopotential approach. A detailed analysis of the relaxed atomic structure reveals that the atoms over the initial unfavourable sites relax to the favourable sites along the lateral plane. The properties of the semicoherent interface can be taken as averages over the different coherent sites. In addition, the interface atoms in relatively favourable regions are dragged near to the interface, while those in unfavourable regions are pushed away from the interface. Therefore, a large war-ping near the interface is made perpendicular to the lateral plane. The calculated adhesions explain the different wetting results from the viewpoint of structural transition. The subsequent analysis of electronic properties demonstrates that adhesions dominate mainly via the strong Al-C covalent bond.
关键词:
first-principles;1st principles;adhesion;surfaces;misfit;1st-principles;wettability;al
X. Q. Yang
,
L. X. Huo
,
Y. F. Zhang and J. X. Yan (School of Material Science and Engineering
,
Tianjin University
,
Tianjin 300072
,
China)
金属学报(英文版)
The buckling formation and influence factors during welding thin - plated structures were investigated based on finite element methods, An engineering treatment method for prdicating the buckling distor- tion was proposed in here. It was used the equivalent applied thermal - load to simulate the welding residual stress,therefore the calculation of complex welding distoriton can be transformed into 3D elas- tic structural applied- load analyses, which can reduce the quantities of calculating works effectively. The validation of the method was verified by comparison of the numerical simulation and experimental results. The simulation of buckling distorition for side - walled structrues of paseenger train was per- formed and the calculation was in agreement with measuring results in general. It was shown that the main factors for producing the buckling were the intermittent fillet and ping the during welding the stiffened beams and columns to the panel.The existence of the free edge of panels would reduce the crit- ical buckling stress and enlarge the deflection obviously,but the continuous weld in closed frames didn' t degrade the buckling situation.
关键词:
welding buckling distortion
,
null
,
null
ZHOU Jiankun LIU Xianghuai CHEN Youshan WANG Xi ZHENG Zhihong HUANG Wei ZOU Shichang Shanghai Institute of Metallurgy
,
Academia Sinica
,
Shanghai
,
China
金属学报(英文版)
The TiN films were synthesized with an alternate process of depositing titanium from a E-gun evaporation source and 40 keV N~+ bombarding onto the target.It is shown from the composi- tion analysis and structure investigations using RBS,AES,TEM,XPS and X-ray diffraction spectrum that the formed fihns are mainly composed of TiN phase with grain size of 30—40 nm and without preferred orientation,the nitrogen content in the film is much less than that in case without N~+ bombarding,and an intermixed region about 40 nm thick exists between the film and the substrate.The films exhibt high microhardness and low friction. ZHOU Jiankun,Ion Beam Laboratory,Shanghai Institute of Metallurgy,Academia Sinica, Shanghai 200050,China
关键词:
TiN film
,
null
Z.L. Ding
,
Y.C. Fan
,
H.B. Qi
,
D.L. Ren
,
J.B. Guo and Z.Q. Jiang Shijiazhuang Railway Institute
,
Shijiazhuang 050043
,
China
金属学报(英文版)
The SiC_p/Al-alloy composite front broke rotors designed for SHANGHAI SANTANA cars were prepared by semi-solid stirring+liquid for ping process. The properties of the composite rotors were examined. The composite brake rotors were subjected to dynamometer tests on a SCHENCK broke testing system, referring to TLll0 standard of VOLKSWAGEN Company. The friction coefficient and thermal response during fade testing and the wear performance of the composite rotors were studied as the function of various parameters, such as braking pressures, initial speeds, initial temperatures, torque and decelerations, and compared with that of conventional cast iron rotors. The results showed that the properties of SiC_p,/Al-alloy composite rotors can achieve the requirements of commercial cast iron rotor.s. The results also suggested that the friction coefficients of composite rotors under different broking conditions are within the deviation band specified by the TLll0 standard, and the temperature rise of the composite rotors at the cud of each fade stop is lower than that of the cast iron rotors. The wear resistance of composite rotors was higher than that of cast iron rotors. The friction and wear mechanism are analyzed.
关键词:
SiC_p/Al-alloy composite
,
null
,
null
,
null
Physical Review B
The assignment of the absorption spectrum of Y3Fe5O12 (YIG) made by Scott et al. [Phys. Rev. B 10, 971 (1974)] is shown to be incorrect and a new one is made by diagonalizing the complete cubic crystal-field matrices for d5 ions, involving spin-orbit interaction, given by Zhou et al. [Phys. Rev. B 44, 7499 (1991)]. The Racah parameters B and C, the crystal-field parameter Dq, and the spin-orbit coupling coefficient zeta are determined (in units of cm-1) as B = 783.3(530), C = 2928(3220), Dq = 1336(1300), zeta = 395 for octahedral Fe3+, and B = 606.1(705), C = 2696(2730), Dq = -1117.3(560), zeta = 335 for tetrahedral Fe3+, where the numerals in parentheses are the values adopted by Scott et al. Furthermore, the cubic zero-field splitting parameter a of Fe3+ in YIG is calculated to be a(oct) = 156 X 10(-4) cm-1 and a(tet) = 58.6 X 10(-4) cm-1. The value for a(oct) differs from the value of 189 X 10(-4) cm-1 found for Fe3+ in Y3Ga5O12:Fe3+. These results support speculations made by Geschwind [Phys. Rev. 121, 363 (1961)].
关键词:
fe3+;mn2+
钱鹏
,
李兴华
量子电子学报
doi:10.3969/j.issn.1007-5461.2015.06.008
基于量子信道加密原理,结合Ping-Pong协议控制模式和信息模式的概念,提出了一个量子安全直接通信协议.在此协议中,发送者和接收者用n对Bell态作为量子信道,发送者用controlled-Not操作将单粒子纠缠入量子信道,接收者用controlled-Not操作将单粒子与量子信道解纠缠.通信双方依次执行控制模式和信息模式,控制模式检测窃听,信息模式发送秘密信息.控制模式和信息模式均不会对已建立的量子信道造成破坏,因此建立量子信道的过程仅需执行一次,此后通信双方可以反复进行控制模式和信息模式,从而不断进行窃听检测和秘密信息传输.
关键词:
量子光学
,
量子安全直接通信
,
信道加密
,
窃听检测
