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18th International Conference on High pressure Science and Technology

作者： r.C.Yu L.C.Chen J.L.Zhu F.Y.Li Z.X.Liu Z.C.Qin T.N.Yu X.F.Duan Z.Zhang C.Q.Jin laboratory for Extreme Condition physics Institute of physics Center for Condensed Matter physics High pressure research Center Chinese Academy of Sciences p.O.Box 603 beijing 100080 p.r.china beijing laboratory of electron microscopy Institute of physics Center for Condensed Matter physics Chinese Academy of Sciences p.O.Box. 2724 beijing 100080 p.r.china

＜正＞C3N4H4 was treated under 6.0 Gpa and 1500℃ for 2.5 minutes. The powder X-ray measurement shows that the sample was decomposed and hexagonal graphite phase formed. Transmission electron microscopy studies show that small amount of diamond and amorphous carbon phases coexited with graphite phase. parallel electron energy loss spectroscopy analysis was also carried out for these phases. Introduction Diamond has been widely used due to its hardness. To most common knowlege, there is no material that can compete with it. However, in 1985, Cohn predicted a new superhard material of a covalent bonded carbon-nitrogen alloy（β-C3N4）, which has the same or even higher hardness of diamond, based on a theoretical work[l]. Motivated by the prediction, a lots of scientists have attempted to synthesize C-N compounds which may not exist in nature[2,3]. In this paper, we report the products of C3N4H4 treated by high temperature - high pressure. Experiments Synthesis experiments were performed with a six-anvil 600 ton high pressure device. The C3N4H4（2-amino,1,3,5-triazine） powders were wrapped by pt or Ti thin slice and sealed into a BN sample cell. The Ni-based alloy flats were put to the both sides of the sample as the catalyst. In the experiment, a pressure of 6.0 Gpa and a temperature of 1500℃ were applied for 2.5 minutes. results and Discussion Here it should be pointed out that no carbon nitride crystals were obtained in our experiments. X-ray pattern of the treated sample shows that C3N4H4 were decomposed under high pressure and graphite phase formed and hexagon graphite phase formed. The samples were also examnied by high resolution transmission electron microscopy（HrTEM）. Three morphologies were observed in the HrTEM experiments. The majority phase which were observed frequently in the sample was hexagonal graphite phase. This is concided with the XrD result. Besides the majority graph

关键词： High pressure C3N4H4 Diamond Graphite

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Application of cathodoluminescence to zircon in FEG-ESEM

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progress in Natural Science:Materials International 2006年第9期16卷 919-924页

作者： CHEN Li , XU Jun and SU Li (electron microscopy laboratory, School of physics, peking University, beijing 100871, china Geology Experimental Center, china University of Geoscience, beijing 100083, china) electron microscopy laboratory School of Physics Peking University Beijing 100871 China Geology Experimental Center China University of Geoscience Beijing 100083 China

Cathodoluminescence (CL) image analysis of zircon is a key step of mineral micro-area compositional investigation and U-(Th)-pb dating. We introduce a system consisting of field emission ESEM and high performance cathodoluminescence. This system has obvious advantages in imaging resolution and CL spectrum. We acquired some zircon CL images and spectra to demonstrate the ability of this system. Our results show that this system has a great potential application to characterize and identify the genesis of zircon.

关键词： zircon cathodoluminescence ESEM.

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Microstructure in Ni80 Fe20/Cu magneticmultilayers and spin valve

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电子显微学报 2000年第1期 17-25页

作者： WANG Wen\|dong\ SUN Hai\|ping\ ZHANG Ze (beijing laboratory of electron microscopy,Institute of physics,Chinese Academy of Sciences,beijing,100080,p.r.china)

用高分辨电子显微学及平行电子能量损失谱方法研究了Ni80Fe20Cu基磁性多层膜和自旋阀的显微结构。高分辨像显示,磁性多层膜及自旋阀均具有沿薄膜生长方向的柱晶结构。Ni,Fe,Cu和Mn元素的成分分布图显示,柱晶内仍保持完整的层状结构。沿... 详细信息

用高分辨电子显微学及平行电子能量损失谱方法研究了Ni80Fe20Cu基磁性多层膜和自旋阀的显微结构。高分辨像显示,磁性多层膜及自旋阀均具有沿薄膜生长方向的柱晶结构。Ni,Fe,Cu和Mn元素的成分分布图显示,柱晶内仍保持完整的层状结构。沿薄膜生长方向的自旋阀元素分布曲线分析表明,NiFe层中的Ni元素沿柱晶晶界向相邻Cu层扩散。讨论了这些低维磁电子学材料的显微结构对磁输运性能的影响。

关键词： Fe 磁性多层膜显微结构柱晶薄膜生长晶体生长高分辨电子显微学自旋阀 Cu magneticmultilayers and spin valve

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preparation of NiFe binary alloy nanocrystals for nonvolatile memory applications

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Science china(Technological Sciences) 2010年第9期53卷 2320-2322页

作者： WANG Li,SUN HongFang,ZHOU HuiHua & ZHU Jing beijing National Center for electron microscopy laboratory,Department of Materials Science and Engineering,Tsinghua University,beijing 100084,china 1. beijing National Center for electron microscopy laboratory Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

In this work,an idea which applies binary alloy nanocrystal floating gate to nonvolatile memory application was *** relationship between binary alloy’s work function and its composition was discussed theoretically.A nanocrystal floating gate structure with NiFe nanocrystals embedded in SiO2 dielectric layers was fabricated by magnetron *** micro-structure and composition deviation of the prepared NiFe nanocrystals were also investigated by TEM and EDS.

关键词： nanocrystal nonvolatile memory work function magnetron sputtering

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Investigation of a New Exsolved Cu-Fe-S phase in“Abnormal Sphalerite”

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Acta Geologica Sinica(English Edition) 1991年第1期65卷 27-36,110-111页

作者： Li Jiuling Wang Su Institute of Mineral Deposits, Chinese Academy of Geolgical Sciences,beijing beijing laboratory of electron microscopy, Chinese Academy of Sciences, beijing Institute of Mineral Deposits Chinese Academy of Geolgical Sciences Beijing China

A new exsolved copper-iron-sulfur phase in sphalerite has been found in the Dajing cassiterite- sulfidecopper-silver-tin deposit, Inner Mongolia, china. After investigating the optical properties, chemical composi-tion, crystal structure and exsolved Characters of the exsolved phase, the authors present important evidencefor its being a new exsolved copper-iron-sulfur phase mineral. Its formation mechenism is discussed in consider-ing heating experiments, phase equilibrium data and the geology of the deposit.

关键词： ph Fe Abnormal Sphalerite Cu

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The formation depth of coesite-bearing eclogite,Dabie UHpM zone,china,modified by tectono-original additional hydrostatic pressure

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Chinese Science Bulletin 1999年第5期44卷 398-411页

作者： LU Guxian, CHEN Jing, LIU ruixun and LI Xiaobo Institute of Geomechanics , beijing 100081, china electron microscopy laboratory, peking University, beijing 100871, china Department of Geology, peking University, beijing 100871, china Institute of Geological Information , beijing 100037, china Institute of Geomechanics Beijing China electron microscopy laboratory Peking University Beijing China Department of Geology Peking University Beijing China Institute of Gelogical Information Beijing China

The knowledge that hydrostatic pressure is equal to the gravity value of the overlying rocks in studying a dynamic state of certain underground site is argued. It is suggested that the stress field T in the crust is a combination or superposition of total hydrostatic pressure p with differential stress σ,and the total hydrostatic pressure p at any point in the crust comprises two parts: one is spherical stress tensor pG caused by the gravity, and the other is spherical stress tensor ps caused by tectonic stress; therefore p could not be attributed to the gravity of overlying rocks only. The results obtained by a finite-element simulation indicate that the tectono-original additional hydrostatic pressures ps decrease gradually from the compressive zone （pcp>Sp>） to the shear zone (pSHp>sp>)and to the tensile zone （pTp>sp>）, i.e.pcp>sp>>psHp>sp>>pTp>sp> in the same depth. On the basis of the above-mentioned research, the method of measurement and calculation of metallogenetic depth corrected by ps is

关键词： formation depth tectonic additional hydrostatic pressure Dabie UHpM zone coesite-bearing eclogite expansion-cracking texture tectonic physicochemistry.

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Anomalous magnetotransport in LaMn_(1-x)Te_xO_3

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Science china(physics,Mechanics & Astronomy) 2009年第7期52卷 987-992页

作者： TAN GuoTai1,2, CHEN ZhengHao3 & ZHANG XiaoZhong4,5 1 Key laboratory of Beam Technology & Materials Modification of the Ministry of Education, Institute of Low Energy Nuclear physics, beijing Normal University, beijing 100875, china 2 beijing radiation Center, beijing 100875, china 3 laboratory of Optical physics, Institute of physics, Chinese Academy of Sciences, beijing 100080, china 4 Key laboratory of Advanced Materials of the Ministry of Education, Department of Materials Science and Engineering, Tsinghua University, beijing 100084, china 5 beijing National Center for electron microscopy, Tsinghua University, beijing 100084, china 1. Key laboratory of Beam Technology & Materials Modification of the Ministry of Education Institute of Low Energy Nuclear Physics Beijing Normal University Beijing 100875 China 2. beijing radiation Center Beijing 100875 China 3. laboratory of Optical physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China 4. Key laboratory of Advanced Materials of the Ministry of Education Department of Materials Science and Engineering Tsinghua University Beijing 100084 China 5. beijing National Center for electron microscopy Tsinghua University Beijing 100084 China

The LaMn1-xTexO3+δ (x=0.1, 0.2, 0.3) were synthesized using solid-state reaction method for the first time. X-ray photoemission spectrum (XpS) shows that in the samples the Te ions have a valence of Te4+, and Mn3+ ions are partly converted into Mn2+ and Mn4+ due to the excess oxygen and Te doping. The magnetotransport associated with Mn2+, Mn3+ and Mn4+ was investigated. The experimental results show that the samples are insulator at 0 T when the amount of Mn3+ is much larger or less than the sum of Mn2+ and Mn4+; by contrast, the samples display metal to insulator transition with increasing temperature when the amount of Mn3+ is close to the sum of Mn2+ and Mn4+. These anomalous magnetotransport behaviors were analyzed in the frame of the double-exchange (DE) mechanism.

关键词： colossal magnetoresistance La-Te-Mn-O magnetotransport

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MECHANISMS OF α_2→α_2/γ pHASE TrANSFOrMATION IN A TiAL ALLOY

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Acta Metallurgica Sinica(English Letters) 1995年第Z1期8卷 597-602页

作者： XU Qiang LEI Changhui (beijing laboratory of electron microscopy. Chinese Academy of Sciences, p. O. Box 2724.100080 )beijing, china.ZHANG Yonggang (Department of Materials Science and Engineering, beijing University of Aeronautics and Astronautics, 1000 beijing Lab of electron microscopy Chinese Acad of Sciences Beijing China

A Ti-45at.%Al alloy which was solution-treated at 1350℃ for 30 minutes and quenched in water is employed to explore mechanisms of α_2→γphase transformation. The ageing process of the quenched alloy has been in situ studied it has been found that the γ lamellae can precipitate in the α_2 matrix by two mechanisms. When The alloy is aged at 700℃, the stacking faults pre-existing in the α_2 matrix start to grow and more are *** the increase of ageing time and ageing temperature the density of stacking faults is increased and the γ lamellae then precipitate. This isα diffusion-controlled process. Alternatively, the γ lamellae may be formed from the α_2 matrix by 1/3(1100) shearing on the (0001) plane. The latter mechanism implies that the strain-induced transformation may occur, which is confirmed by deformation of the quenched alloy.

关键词： TiAl phase transformation lamellar structure

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pHASE EXTENSION AND STrUCTUrE ANALYSIS BY THE MAXIMUM ENTrOpY METHOD

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Acta Metallurgica Sinica(English Letters) 1998年第4期11卷 241-254页

作者： G.B.Hu and Q.B.Yang (Department of physics, Xiangtan University, Xiangtan 411105, china)(beijing laboratory of electron microscopy, Center for Condensed Matter physics, The Chinese Academy of Sciences, p. O. Box 2724, beijing 100080, china) Xiangtan Univ Xiangtan China

Excellent results are obtained in structure analysis with jew phases of structure factors by the maximum-entropy method (MEM) for CaGaN pbCO3 and reBe22 single crystals. The computation time and memory space are minim... 详细信息

关键词： maximum entropy method structure analysis phase extension,symmetry

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DEFOrMATION　AND　FrACTUrE　MECHANISMS　OF　TWO－pHASE　TiAl－BASED　ALLOYS　WITH　FULLY　LAMELLAr　MICrOSTrUCTUrE

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Acta Metallurgica Sinica(English Letters) 1995年第Z1期8卷 359-368页

作者： Y. G .Zhang, C. Q. Chen (beijing University of Aeronautics and Astronautics, beijing 100083, china)Q. Xu (beijing laboratory of electron microscopy, Chinese Academy of Sciences. beijing,china)M. C. Chaturvedi (The University of Manitoba, Winnipeg, Manito beijing Univ of Aeronautics and Astronautics Beijing China

A two-phase TiAl-based alloy with fully lamellar structure has been deformed al room temperature and the deformed microstructures have been examined in dtails by optical microscopy(OM), scanning electron microscopy(SEM) and transmission electron microscopy(TEM) . Deformation mechanisms in the γ-TiAl phase has been defined and the role of grain boundaries in the deformation and fracture has been assessed Some of the mechanisms of interactions between twinning or gliding dislocations and three types of γ γ domain boundaries or γ α_2 interface in a lamellar grain have been identified and resistance of the various domain boundaries or the interface to the propagation of twinning has been evaluated

关键词： TiAl Deformation mechanism Lamellae Twinning

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