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Effect of slow shot speed on externally solidified crystal,porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy
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作者 Wen-ning Liu Wei Zhang +6 位作者 Peng-yue Wang Yi-xian Liu Xiang-yi Jiao Ao-xiang Wan Cheng-gang Wang Guo-dong Tong Shou-mei Xiong 《China Foundry》 SCIE EI CAS CSCD 2024年第1期11-19,共9页
The effect of slow shot speed on externally solidified crystal(ESC),porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy was investigated by optical microscopy(OM),scanning electron mi... The effect of slow shot speed on externally solidified crystal(ESC),porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy was investigated by optical microscopy(OM),scanning electron microscopy(SEM)and laboratory computed tomography(CT).Results showed that the newly developed AlSi9MnMoV alloy exhibited improved mechanical properties when compared to the AlSi10MnMg alloy.The AlSi9MnMoV alloy,which was designed with trace multicomponent additions,displays a notable grain refining effect in comparison to the AlSi10MnMg alloy.Refining elements Ti,Zr,V,Nb,B promote heterogeneous nucleation and reduce the grain size of primaryα-Al.At a lower slow shot speed,the large ESCs are easier to form and gather,developing into the dendrite net and net-shrinkage.With an increase in slow shot speed,the size and number of ESCs and porosities significantly reduce.In addition,the distribution of ESCs is more dispersed and the net-shrinkage disappears.The tensile property is greatly improved by adopting a higher slow shot speed.The ultimate tensile strength is enhanced from 260.31 MPa to 290.31 MPa(increased by 11.52%),and the elongation is enhanced from 3.72%to 6.34%(increased by 70.52%). 展开更多
关键词 hypoeutectic Al-Si alloy high pressure die casting POROSITY externally solidified crystal tensile property
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Crystallization and characteristics of {100}-oriented diamond with CH4N2S additive under high pressure and high temperature
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作者 Yong Li Debing Tan +3 位作者 Qiang Wang Zhengguo Xiao Changhai Tian Lin Chen 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第9期549-552,共4页
Diamond crystallization was carried out with CH4N2S additive in the FeNiCo-C system at pressure 6.0 GPa and temperature ranging from 1290 ℃ to 1300 ℃. The crystallization qualities of the synthetic crystals were cha... Diamond crystallization was carried out with CH4N2S additive in the FeNiCo-C system at pressure 6.0 GPa and temperature ranging from 1290 ℃ to 1300 ℃. The crystallization qualities of the synthetic crystals were characterized by Raman spectra and the Raman peaks located at 1331 cm-1. Fourier transform infrared (FTIR) results showed that the hydrogen-related absorption peak of the as-grown diamond was at 2920 cm-1, respectively. Interestingly, A-center nitrogen was observed in the obtained diamond and the characteristic absorption peaks located at 1095 cm-1 and 1282 cm-1. Especially, the absorption peak at 1426 cm-1 attributing to the aggregation B-center nitrogen defect was distinctly found when the CH4N2S content reached 0.3 mg in the synthesis system, which was extremely rare in synthetic diamond. Furthermore, optical color centers in the synthesized crystals were investigated by photoluminescence (PL). 展开更多
关键词 high pressure and high temperature DIAMOND crystallization CHARACTERISTICS
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Growth and annealing study of hydrogen-doped single diamond crystals under high pressure and high temperature 被引量:4
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作者 李勇 贾晓鹏 +5 位作者 胡美华 刘晓兵 颜丙敏 周振翔 张壮飞 马红安 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第5期652-656,共5页
A series of diamond crystals doped with hydrogen is successfully synthesized using LiH as the hydrogen source in a catalyst-carbon system at a pressure of 6.0 GPa and temperature ranging from 1255 C to 1350 C.It is sh... A series of diamond crystals doped with hydrogen is successfully synthesized using LiH as the hydrogen source in a catalyst-carbon system at a pressure of 6.0 GPa and temperature ranging from 1255 C to 1350 C.It is shown that the high temperature plays a key role in the incorporation of hydrogen atoms during diamond crystallization.Fourier transform infrared micro-spectroscopy reveals that most of the hydrogen atoms in the synthesized diamond are incorporated into the crystal structure as sp 3-CH 2-symmetric(2850 cm-1) and sp 3 CH 2-antisymmetric vibrations(2920 cm-1).The intensities of these peaks increase gradually with an increase in the content of the hydrogen source in the catalyst.The incorporation of hydrogen impurity leads to a significant shift towards higher frequencies of the Raman peak from 1332.06 cm-1 to 1333.05 cm-1 and gives rise to some compressive stress in the diamond crystal lattice.Furthermore,hydrogen to carbon bonds are evident in the annealed diamond,indicating that the bonds that remain throughout the annealing process and the vibration frequencies centred at 2850 and 2920 cm-1 have no observable shift.Therefore,we suggest that the sp 3 C-H bond is rather stable in diamond crystals. 展开更多
关键词 high pressure and high temperature hydrogen-doped diamond crystals ANNEALING LiH additives
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B-C Bond in Diamond Single Crystal Synthesized with h-BN Additive at High Pressure and High Temperature 被引量:2
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作者 李勇 周振翔 +4 位作者 管学茂 李尚升 王应 贾晓鹏 马红安 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第2期137-140,共4页
The synthesis of diamond single crystal in the Fe64Ni36-C system with h-BN additive is investigated at pressure 6.5 GPa and temperature range of 1300-1400℃. The color of the obtained diamond crystals translates from ... The synthesis of diamond single crystal in the Fe64Ni36-C system with h-BN additive is investigated at pressure 6.5 GPa and temperature range of 1300-1400℃. The color of the obtained diamond crystals translates from yellow to dark green with increasing the h-BN addition. Fourier-transform infrared (FTIR) results indicate that sp2 hybridization B-N-B and B-N structures generate when the additive content reaches a certain value in the system. The two peaks are located at 745 and 1425cm-1, respectively. Fhrthermore, the FTIR characteristic peak resulting from nitrogen pairs is noticed and it tends to vanish when the h-BN addition reaches 1.1 wt%. Furthermore, Raman peak of the synthesized diamond shifts down to a lower wavenumber with increasing the h-BN ~ddition content in the synthesis system. 展开更多
关键词 BN in of B-C Bond in Diamond Single crystal Synthesized with h-BN Additive at high pressure and high Temperature with
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Synthesis and characterizations of boron and nitrogen co-doped high pressure and high temperature large single-crystal diamonds with increased mobility 被引量:2
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作者 Xin-Yuan Miao Hong-An Ma +4 位作者 Zhuang-Fei Zhang Liang-Chao Chen Li-Juan Zhou Min-Si Li Xiao-Peng Jia 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第6期625-630,共6页
We synthesized and investigated the boron-doped and boron/nitrogen co-doped large single-crystal diamonds grown under high pressure and high temperature(HPHT) conditions(5.9 GPa and 1290℃). The optical and electrical... We synthesized and investigated the boron-doped and boron/nitrogen co-doped large single-crystal diamonds grown under high pressure and high temperature(HPHT) conditions(5.9 GPa and 1290℃). The optical and electrical properties and surface characterization of the synthetic diamonds were observed and studied. Incorporation of nitrogen significantly changed the growth trace on surface of boron-containing diamonds. X-ray photoelectron spectroscopy(XPS) measurements showed good evident that nitrogen atoms successfully incorporate into the boron-rich diamond lattice and bond with carbon atoms. Raman spectra showed differences on the as-grown surfaces and interior between boron-doped and boron/nitrogen co-doped diamonds. Fourier transform infrared spectroscopy(FTIR) measurements indicated that the nitrogen incorporation significantly decreases the boron acceptor concentration in diamonds. Hall measurements at room temperature showed that the carriers concentration of the co-doped diamonds decreases, and the mobility increases obviously. The highest hole mobility of sample BNDD-1 reached 980 cm^(2)·V^(-1)·s^(-1), possible reasons were discussed in the paper. 展开更多
关键词 high pressure and high temperature(HPHT) DIAMOND growth of crystal boron and nitrogen codoped diamond
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Synthesis of large diamond crystals containing high-nitrogen concentration at high pressure and high temperature using Ni-based solvent by temperature gradient method 被引量:1
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作者 黄国锋 贾晓鹏 +4 位作者 李尚升 张亚飞 李勇 赵明 马红安 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第11期662-666,共5页
This paper reprots that with Ni-based catalyst/solvent and with a dopant of NAN3, large green single crystal diamonds with perfect shape are successfully synthesized by temperature gradient method under high pressure ... This paper reprots that with Ni-based catalyst/solvent and with a dopant of NAN3, large green single crystal diamonds with perfect shape are successfully synthesized by temperature gradient method under high pressure and high temperature in a China-type cubic anvil high-pressure apparatus (SPD-6 × 1200), and the highest nitrogen concentration reaches approximately 121-1257 ppm calculated by infrared absorption spectra. The synthesis conditions are about 5.5 CPa and 1240-1300 ℃. The growth behaviour of diamond with high-nitrogen concentration is investigated in detail. The results show that, with increasing the content of NaN3 added in synthesis system, the width of synthesis temperature region for growth high-quality diamonds becomes narrower, and the morphology of diamond crystal is changed from cube-octahedral to octahedral at same temperature and pressure, the crystal growth rate is slowed down, nevertheless, the nitrogen concentration doped in synthetic diamond increases. 展开更多
关键词 high temperature and high pressure nitrogen-doped diamond crystal temperature gra- dient method additive NaN3
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Influence of annealing treatment on as-grown Ib-type diamond crystal at a high temperature and high pressure
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作者 黄国锋 尹辑文 +5 位作者 白洪波 胡义嘎 凯丽 静婧 马红安 贾晓鹏 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第10期491-495,共5页
In this paper,we report on the influence of annealing treatment on as-grown Ib-type diamond crystal under high pressure and high temperature in a china-type cubic anvil high-pressure apparatus.Experiments are carried ... In this paper,we report on the influence of annealing treatment on as-grown Ib-type diamond crystal under high pressure and high temperature in a china-type cubic anvil high-pressure apparatus.Experiments are carried out at a pressure of 7.0 GPa and temperatures ranging from 1700 C to 1900 C for 1 h.Annealing treatment of the diamond crystal shows that the aggregation rate constant of nitrogen atoms in the as-grown Ib-type diamond crystal strongly depends on diamond morphology and annealing temperature.The aggregation rate constant of nitrogen remarkably increases with the increase of annealing temperature and its value in octahedral diamond is much higher than that in cubic diamond annealed at the same temperature.The colour of octahedral diamond crystal is obviously reduced from yellow to nearly colorless after annealing treatment for 1 h at 1900 C,which is induced by nitrogen aggregation in a diamond lattice.The extent of nitrogen aggregation in an annealed diamond could approach approximately 98% indicated from the infrared absorption spectra.The micro-Raman spectrum reveals that the annealing treatment can improve the crystalline quality of Ib-type diamond characterized by a half width at full maximum at first order Raman peak,and therefore the annealed diamond crystals exhibit nearly the same properties as the natural IaA-type diamond stones of high quality in the Raman measurements. 展开更多
关键词 high pressure and high temperature diamond crystal ANNEALING nitrogen aggregation
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Dislocation Mechanism of Diamond Crystal Growth from Fe-Ni-C System at High Temperature-High Pressure
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作者 LongweiYIN ZhaoyinHAO 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2002年第1期66-68,共3页
Some dislocations, which are generated in the diamond single crystal during the diamond crystal growth from Fe-Ni-C system, may affect diamond crystal growth mode at high temperature-high pressure (HPHT). The concentr... Some dislocations, which are generated in the diamond single crystal during the diamond crystal growth from Fe-Ni-C system, may affect diamond crystal growth mode at high temperature-high pressure (HPHT). The concentric dislocation loops were successfully examined by Moire images. The surface morphologies of growing and as-grown diamond single crystals were observed by scanning electron microscopy (SEM). The concentric dislocation loops formation process and their effect on the diamond crystal growth mode were analyzed. It should be noted that whatever the nature of the dislocation is, should the Burgers vector of dislocation has a component at the direction normal to the growth interface, the dislocation will make the face parallel to the growth interface grow into spiral face. The presence of consecutive spiral steps on the diamond crystal surface also provides a direct evidence of the dislocation mechanism of diamond crystal growth. 展开更多
关键词 high temperature-high pressure DIAMOND crystal growth Fe-Ni-C system
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CRYSTALLIZATION OF METALLIC GLASS Zr_70Cu_30 UNDER HIGH PRESSURE
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作者 SHEN Dejiu WU Haoquan Yanshan University,Qinhuangdao,China SHEN Zhongyi +1 位作者 CHEN Guiyu YIN Xiujun Institute of Physics,Academia Sinica,Beijing,China Iectrurer,Department of Materials Engineering,Yanshan University,Qinhuangdao 066004,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1993年第8期137-140,共4页
Crystallization temperature of the metallic glass Zr_(70)Cu_(30),observed by X-ray diffraction analysis,may be increased about 20℃,the superior limit of increase range of the temperature is about 30℃,under high pres... Crystallization temperature of the metallic glass Zr_(70)Cu_(30),observed by X-ray diffraction analysis,may be increased about 20℃,the superior limit of increase range of the temperature is about 30℃,under high pressure up to 2GPa.Besides α-Zr and CuZr_2, the Cu_(10)Zr_7 phase was newly obtained as another crystallization product. 展开更多
关键词 metallic glass Zr_(70)CU_(30) crystallization high pressure
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Growth and annealing study of hydrogen-doped single diamond crystals under high pressure and high temperature
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作者 李勇 贾晓鹏 +5 位作者 胡美华 刘晓兵 颜丙敏 周振翔 张壮飞 马红安 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第5期656-660,共5页
A series of diamond crystals doped with hydrogen is successfully synthesized using LiH as the hydrogen source in a catalyst-carbon system at a pressure of 6.0 GPa and temperature ranging from 1255 C to 1350 C.It is sh... A series of diamond crystals doped with hydrogen is successfully synthesized using LiH as the hydrogen source in a catalyst-carbon system at a pressure of 6.0 GPa and temperature ranging from 1255 C to 1350 C.It is shown that the high temperature plays a key role in the incorporation of hydrogen atoms during diamond crystallization.Fourier transform infrared micro-spectroscopy reveals that most of the hydrogen atoms in the synthesized diamond are incorporated into the crystal structure as sp 3-CH 2-symmetric(2850 cm-1) and sp 3 CH 2-antisymmetric vibrations(2920 cm-1).The intensities of these peaks increase gradually with an increase in the content of the hydrogen source in the catalyst.The incorporation of hydrogen impurity leads to a significant shift towards higher frequencies of the Raman peak from 1332.06 cm-1 to 1333.05 cm-1 and gives rise to some compressive stress in the diamond crystal lattice.Furthermore,hydrogen to carbon bonds are evident in the annealed diamond,indicating that the bonds that remain throughout the annealing process and the vibration frequencies centred at 2850 and 2920 cm-1 have no observable shift.Therefore,we suggest that the sp 3 C-H bond is rather stable in diamond crystals. 展开更多
关键词 high pressure and high temperature hydrogen-doped diamond crystals ANNEALING LiH additives
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In-situ high pressure X-ray diffraction studies of orthoferrite SmFeO_3 被引量:1
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作者 李娜娜 李岩 +7 位作者 李会 唐瑞莲 赵永胜 韩丹丹 马艳梅 崔启良 朱品文 王欣 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第6期635-638,共4页
The high-pressure behaviors of SmFeO3 are investigated by angle-dispersive synchrotron X-ray powder diffraction under a pressure of up to 40.3 GPa at room temperature. The crystal structure of SmFeO3 remains stable at... The high-pressure behaviors of SmFeO3 are investigated by angle-dispersive synchrotron X-ray powder diffraction under a pressure of up to 40.3 GPa at room temperature. The crystal structure of SmFeO3 remains stable at up to the highest pressure. The different pressure coefficients of the normalized axial compressibility are obtained to be βa = 0.60 × 10-3 GPa-1,βb = 0.79 × 10-3 GPa-1, βc = 1.28 × 10-3 GPa- 1, and the bulk modulus (B0) is determined to be 293(3) GPa by fitting the pressure-volume data using the Birch-Murnaghan equation of state. Furthermore, the larger compressibility of the FeO6 octahedra suggests the evolution of the orthorhombic structure towards higher symmetry configuration at high pressures. 展开更多
关键词 crystal structure high-pressure X-ray diffraction
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High-pressure-activated carbon tetrachloride decomposition
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作者 陈元正 周密 +2 位作者 孙美娇 里佐威 孙成林 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第2期216-219,共4页
The pressure-induced molecular dissociation as one of the fundamental problems in physical sciences has aroused many theoretical and experimental studies. Here, using a newly developed particle swarm optimization algo... The pressure-induced molecular dissociation as one of the fundamental problems in physical sciences has aroused many theoretical and experimental studies. Here, using a newly developed particle swarm optimization algorithm, we investigate the high-pressure-induced molecular dissociation. The results show that the carbon tetrachloride (CC14) is unstable and dissociates into C2C16 and C12 under approximately 120 GPa and more. The dissociation is confirmed by the lattice dynamic calculations and electronic structure of the Pa3 structure with pressure evolution. The dissociation pressure is far larger than that in the case of high temperature, indicating that the temperature effectively reduces the activation barrier of the dissociation reaction of CC14. This research improves the understanding of the dissociation reactions of CC14 and other halogen compounds under high pressures. 展开更多
关键词 crystal structure prediction DECOMPOSITION carbon tetrachloride high pressure
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Structural and electrical transport properties of Dirac-like semimetal PdSn4 under high pressure
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作者 Bowen Zhang Chao An +5 位作者 Yonghui Zhou Xuliang Chen Ying Zhou Chunhua Chen Yifang Yuan Zhaorong Yang 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第12期280-285,共6页
We conducted in-situ high-pressure synchrotron x-ray diffraction(XRD) and electrical transport measurements on Dirac-like semimetal Pd Sn4 in diamond anvil cells with quasi-hydrostatic pressure condition up to 44.5 GP... We conducted in-situ high-pressure synchrotron x-ray diffraction(XRD) and electrical transport measurements on Dirac-like semimetal Pd Sn4 in diamond anvil cells with quasi-hydrostatic pressure condition up to 44.5 GPa–52.0 GPa. The XRD data show that the ambient orthorhombic phase(Ccca) is stable with pressures to 44.5 GPa, and the lattice parameters and unit-cell volume decrease monotonously upon compression. The temperature dependence of the resistance exhibits a metallic conduction and follows a Fermi-liquid behavior below 50 K, both of which keep unchanged upon compression to 52.0 GPa. The magnetoresistance curve at 5 K maintains a linear feature in a magnetic field range of 2.5 T–7 T with increasing pressure to 20.0 GPa. Our results may provide pressure-transport constraints on the robustness of the Dirac fermions. 展开更多
关键词 high pressure Dirac-like semimetal crystal structure electrical transport
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In-situ high-pressure behaviors of double-perovskite Sr_2ZnTeO_6
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作者 韩丹丹 高伟 +6 位作者 李娜娜 唐瑞莲 李会 马艳梅 崔启良 朱品文 王欣 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第5期644-649,共6页
Structural and spectroscopic properties of Sr2ZnTeO6 (SZTO) were investigated by angle-dispersive synchrotron X- ray powder diffraction and Raman spectroscopy in a diamond anvil cell up to 31 GPa at room temperature... Structural and spectroscopic properties of Sr2ZnTeO6 (SZTO) were investigated by angle-dispersive synchrotron X- ray powder diffraction and Raman spectroscopy in a diamond anvil cell up to 31 GPa at room temperature. Although SZTO remained stable up to the highest pressure, the different pressure coefficients of the normalized axial compressibility were obtained as βab=8.16×10-3 GPa-1 andβc=7.61 x 10-3 GPa-1. The bulk modulus B0 was determined to be 190(1) GPa by fitting the pressure-volume data using the Birch-Mumaghan equation of state. All the observed Raman modes exhibited a broadening effect under high pressure. The vibrational band V1 around 765 cm-1, which is associated with the Te-O stretching mode in the basal plane of the TeO6 octahedron had the largest pressure coefficient, and the Griineisen parameters for all the observed phonon modes were also calculated and presented. These parameters could be used to measure the amount of uniaxial or biaxial strain, providing a fundamental tool for monitoring the magnitude of the shift of phonon frequencies with strains. 展开更多
关键词 crystal structure high pressure X-ray diffraction optical spectroscopy
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EFFECT OF PRESSURE ON CRYSTALLIZATION CHARACTERISTICS AND CRYSTALLIZED MICROSTRUCTURE OF AMORPHOUS Al_(85)Ni_(10)Y_(5) ALLOY
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作者 Jiang Xiangyang Chen Zhenhua Zhou Duosan 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 1996年第1期80-84,共5页
The crystallization behaviour of amorphous Al_(85)Ni_(10)Y_(5) alloy under high pressure was investigated.Results showed that the amorphous state can be preserved when the alloy is treated under high pressure at tempe... The crystallization behaviour of amorphous Al_(85)Ni_(10)Y_(5) alloy under high pressure was investigated.Results showed that the amorphous state can be preserved when the alloy is treated under high pressure at temperature below 325℃,the polytropic crystallization takes place when the alloy is treated at 325〜520 ℃ and 3〜6GPa for 1 min;the crystallizing product is nanometer scale supersaturated fee-Al solid solution particles dispersed in amorphous matrix;under 1 GPa pressure amorphous allloy crystallizes in an eutectic way,the crystallizing products are fee-Al,Al_(3)Y,Al_(3)Ni,AlNiY equilibrium crystalline phases etc.High pressure appreciably changes the crystallization mode and the products,elevates the crystallizing temperature. 展开更多
关键词 amorphous alloy crystallization high pressure effect
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New carbon-nitrogen-oxygen compounds as high energy density materials
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作者 沈俊宇 段青卓 +4 位作者 苗俊一 何适 何开华 戴伟 卢成 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第9期381-385,共5页
Molecular crystals are complex systems exhibiting various crystal structures,and accurately modeling the crystal structures is essential for understanding their physical behaviors under high pressure.Here,we perform a... Molecular crystals are complex systems exhibiting various crystal structures,and accurately modeling the crystal structures is essential for understanding their physical behaviors under high pressure.Here,we perform an extensive structure search of ternary carbon-nitrogen-oxygen(CNO)compound under high pressure with the CALYPSO method and first principles calculations,and successfully identify three polymeric CNO compounds with Pbam,C2/m and I4m2symmetries under 100 GPa.More interestingly,these structures are also dynamically stable at ambient pressure,and are potential high energy density materials(HEDMs).The energy densities of Pbam,C2/m and I4m2 phases of CNO are about2.30 kJ/g,1.37 kJ/g and 2.70 kJ/g,respectively,with the decompositions of graphitic carbon and molecular carbon dioxide andα-N(molecular N_(2))at ambient pressure.The present results provide in-depth insights into the structural evolution and physical properties of CNO compounds under high pressures,which offer crucial insights for designs and syntheses of novel HEDMs. 展开更多
关键词 molecular crystals high pressure structure searches first principles calculations high energy density materials
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Diffusion coefficients of natural gas in foamy oil systems under high pressures 被引量:1
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作者 Yan-Yu Zhang Xiao-Fei Sun +1 位作者 Xue-Wei Duan Xing-Min Li 《Petroleum Science》 SCIE CAS CSCD 2015年第2期293-303,共11页
The diffusion coefficient of natural gas in foamy oil is one of the key parameters to evaluate the feasibility of gas injection for enhanced oil recovery in foamy oil reservoirs. In this paper, a PVT cell was used to ... The diffusion coefficient of natural gas in foamy oil is one of the key parameters to evaluate the feasibility of gas injection for enhanced oil recovery in foamy oil reservoirs. In this paper, a PVT cell was used to measure diffusion coefficients of natural gas in Venezuela foamy oil at high pressures, and a new method for deter- mining the diffusion coefficient in the foamy oil was de- veloped on the basis of experimental data. The effects of pressure and the types of the liquid phase on the diffusion coefficient of the natural gas were discussed. The results indicate that the diffusion coefficients of natural gas in foamy oil, saturated oil, and dead oil increase linearly with increasing pressure. The diffusion coefficient of natural gas in the foamy oil at 20 MPa was 2.93 times larger than that at 8.65 MPa. The diffusion coefficient of the natural gas in dead oil was 3.02 and 4.02 times than that of the natural gas in saturated oil and foamy oil when the pressure was 20 MPa. However, the gas content of foamy oil was 16.9 times higher than that of dead oil when the dissolution time and pressure were 20 MPa and 35.22 h, respectively. 展开更多
关键词 Foamy oil Diffusion coefficient - Heavy oil Gas injection high pressure
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Compressive Deformation Induced Nanocrystallization of a Supercooled Zr-Based Bulk Metallic Glass 被引量:2
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作者 郭晓琳 单德彬 +1 位作者 马明臻 郭斌 《Chinese Physics Letters》 SCIE CAS CSCD 2008年第6期2173-2176,共4页
The nanocrystallization behaviour of a bulk Zr-based metallic glass subjected to compressive stress is investigated in the supercooled liquid region. Compared with annealing treatments without compressive stress, comp... The nanocrystallization behaviour of a bulk Zr-based metallic glass subjected to compressive stress is investigated in the supercooled liquid region. Compared with annealing treatments without compressive stress, compressive deformation promotes the development of nucleation and suppresses the coarsening of nanocrystallites at high temperatures. 展开更多
关键词 LIQUID REGION AMORPHOUS-ALLOYS TRANSITION TEMPERATURE PHASE-SEPARATION high-pressure crystallization BEHAVIOR NUCLEATION PLASTICITY MECHANISM
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Effects of Mg on diamond growth and properties in Fe–C system under high pressure and high temperature condition
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作者 黄国锋 郑友进 +5 位作者 李战厂 高强 马卓 史思明 姜宝钢 赵赫 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第8期417-420,共4页
Diamond crystal crystallized in Fe–Mg–C system with Archimedes buoyancy as a driving force is established under high pressure and high temperature conditions. The experimental results indicate that the addition of t... Diamond crystal crystallized in Fe–Mg–C system with Archimedes buoyancy as a driving force is established under high pressure and high temperature conditions. The experimental results indicate that the addition of the Mg element results in the nitrogen concentration increasing from 87 ppm to 271 ppm in the diamond structure. The occurrence of the {100}plane reveals that the surface character is remarkably changed due to the addition of Mg. Micro-Raman spectra indicate that the half width of full maximum is in a range of 3.01 cm^-1–3.26 cm^-1, implying an extremely good quality of diamond specimens in crystallization. 展开更多
关键词 high pressure and high temperature Archimedes buoyancy process diamond crystal Mg metal
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Structural evolution and molecular dissociation of H_(2)S under high pressures
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作者 Wen-Ji Shen Tian-Xiao Liang +4 位作者 Zhao Liu Xin Wang De-Fang Duan Hong-Yu Yu Tian Cui 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第7期436-441,共6页
Solid H_(2)S as the precursor for H_(3)S with incredible superconducting properties under high pressure,has recently attracted extensive attention.Here in this work,we propose two new phases of H_(2)S with P42/n and I... Solid H_(2)S as the precursor for H_(3)S with incredible superconducting properties under high pressure,has recently attracted extensive attention.Here in this work,we propose two new phases of H_(2)S with P42/n and I41/a lattice symmetries in a pressure range of 0 GPa–30 GPa through first-principles structural searches,which complement the phase transition sequence.Further an ab initio molecular dynamics simulation confirms that the molecular phase P2/c of H_(2)S is gradually dissociated with the pressure increasing and reconstructs into a new P2_(1)/m structure at 160 GPa,exhibiting the superconductivity with Tc of 82.5 K.Our results may provide a guidance for the theoretical study of low-temperature superconducting phase of H_(2)S. 展开更多
关键词 high pressure crystal structure phase transition SUPERCONDUCTIVITY
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