共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
Russian Physics Journal - The paper studies the fracture of high-strength projectiles during their interaction with a steel barrier. Three types of the projectile head are considered, namely plate,... 相似文献
3.
Russian Physics Journal - The paper studies the crack propagation in the nickel single crystal under uniaxial tension along the [010] crystallographic direction using the molecular dynamics... 相似文献
4.
基于密度泛函理论的第一性原理计算方法,研究了Pt原子在五边形石墨烯(PG)上的吸附与动力学行为.研究结果表明,单个Pt原子在PG上虽然具有较大的吸附能及较高的扩散势垒,却不能够在衬底形成均匀分散的单原子.这是因为,随Pt原子数增加,Ptn(n=1, 2, 3)在PG上的平均结合能也逐渐增加,更倾向于形成团簇,该发现有效否定了之前的报道称Pt能在PG上形成稳定的单原子催化剂这一结论(Phys. Chem. Chem. Phys. 21, 12201 (2019)).基于此,我们考虑对PG施加双轴应变,随着拉伸应力增加,Pt金属原子间的平均结合能逐渐降低,当拉伸应变施加至12%左右时,单个Pt在衬底上的结合能与Pt2在衬底上的平均结合能相等,从而实现PG上均匀分散的Pt单原子催化剂.该结果对五边形石墨烯基材料应变调控实现单原子催化剂提供理论借鉴. 相似文献
5.
Hetero-Epitaxial Diamond Single Crystal Growth on Surface of cBN Single Crystals at High Pressure and High Temperature 下载免费PDF全文
We report a new diamond synthesis process in which cubic boron nitride single crystals are used as seeds, FesoNi20 alloy powder is used as catalyst/solvent and natural flake-like graphite is used as the carbon source. The samples are investigated using laser Raman spectra and x-ray diffraction (XRD). Morphology of the sample is observed by a scanning electron microscope (SEM). Based on the measurement results, we conclude that diamond single crystals have grown on the cBN crystal seeds under the conditions of high temperature 1230℃ and high pressure 4.8 GPa. This work provides an original method for synthesis of high quality hereto-semiconductor with cBN and diamond single crystals, and paves the way for future development. 相似文献
6.
Technical Physics - Mathematical simulation and experiments are used to study plastic strain in nickel [001] single crystals. It is shown that the crystal exhibits self-organization of plastic... 相似文献
7.
高质量AlPO4-5分子筛大单晶的合成与表征 总被引:2,自引:0,他引:2
以拟薄水铝石作为铝源,正磷酸为磷源,正三丙胺(TPA)作模板剂,采用水热法合成了AlPO4 5分子筛.在不同的反应物配比、温度以及晶化时间条件下,得到了不同尺寸的AlPO4 5分子筛单晶.实验表明,反应物质的摩尔比为Al2O3∶P2O5∶TPA∶C2H5OH∶H2O∶HF=1∶1. 2∶2. 66∶80∶1000∶0. 7,反应温度为457K,晶化时间48h是生成六方AlPO4 5分子筛大单晶较适宜的条件;在该反应条件下合成出纵向尺度最大达到2. 0mm、具有完整六方棱柱形态的AlPO4 5分子筛单晶;部分晶体的横向尺度达到0. 31mm.用扫描电镜观察晶体的形貌;AlPO4 5分子筛晶体结构通过SMART1000单晶衍射仪鉴定. 相似文献
8.
9.
Robert J. Jakobsen 《光谱学快报》2013,46(2):61-65
Abstract The use of polarized infrared spectra is a great aid in the assignment of the molecular vibrations of crystals. In spite of this well-known fact, comparatively little use has been made of this powerful tool for studying crystals. The major reason for this lack of use is the difficult, tedious process of growing a single crystal followed by the problems involved in cutting crystal layers thin enough for infrared measurements. 相似文献
10.
V. A. Nikitenko K. É. Tarkpea I. V. Pykanov S. G. Stoyukhin 《Journal of Applied Spectroscopy》2001,68(3):502-507
The radiation defects created in hydrothermal ZnO–Li single crystals by irradiating them with electrons, protons, and highenergy ions have been investigated. The anionic vacancies (Fcenters) in ZnO are established to be the centers of radiationless recombination of the charge carriers with a photoionization energy of 2.3 eV (a signal of the photoEPR with the gfactor for the F+center: g
= 1.9948 and g
= 1.9963). The anionic vacancies in the form of the F and F+ states are a good reference of the electron and hole processes. The [FLi]×centers that correspond to the oxygen vacancies localized near the point defects LiZn are detected. In the temperature range 530–660 K, ZnO crystals display thermally stimulated processes such as the healing of anionic vacancies (530–630 K) and the disappearance of the [FLi]×centers (610–660 K). 相似文献
11.
Strain Avalanches in Microsized Single Crystals:A Theoretical Study of the Relation between the Avalanche Size and Duration 下载免费PDF全文
《中国物理快报》2016,(9)
Single crystal micropillars deform via a sequence of discrete strain avalanches,observed as displacement jumps or stress drops.Here we develop a simple crystal plasticity model to provide a quantitative expression of the relation between avalanche duration and avalanche size.It is found that the avalanche durations in scale with the averaged avalanche sizes only hold for those larger magnitudes.We show that the theoretical predictions are capable of capturing the essential aspects of scaling behaviors from micro-compression tests. 相似文献
12.
Analysis of Transition Mechanism of Cubic Boron Nitride Single Crystals under High Pressure-High Temperature with Valence Electron Structure Calculation 下载免费PDF全文
The possibilities of hexagonal boron nitride(hBN) and lithium boron nitride(Li_3BN_2) transition into cubic boron nitride(cBN) under synthetic pressure 5.0 GPa and synthetic temperature 1700 K are analyzed with the use of the empirical electron theory of solids and molecules. The relative differences in electron density are calculated for dozens of bi-phase interfaces hBN/cBN, Li_3BN_2/cBN. These relative differences of hBN/cBN are in good agreement with the first order of approximation(10%), while those of Li_3BN_2/cBN are much greater than 10%.This analysis suggests that Li_3BN_2 is impossible to be intermediate phase but is a catalyst and cBN should be directly transformed by hBN. 相似文献
13.
Kunitsyna T. S. Teplyakova L. A. Potekaev A. I. Starenchenko V. A. 《Russian Physics Journal》2019,61(12):2253-2257
Russian Physics Journal - The paper presents research results of the deformation-induced surface topography of Ni3Fe alloy single crystals oriented toward the multiple shear bands at uniaxial... 相似文献
14.
15.
High-quality diamond single crystals with micron grain size are synthesized with a new high-pressure and high-temperature (HPHT) synthesis technique in a cubic anvil high pressure apparatus. Morphology of the synthesized diamonds is observed by a scanning electron microscope (SEM). The samples are characterized using laser Raman spectra. The results show that the new synthesis technique improves the nucleation of diamond greatly, and diamond single crystals with perfect morphology and micron grain size are successfully synthesized, with the average grain size of about 6μm. This work provides a new synthesis technique to implement industrialization of high-quality diamond single crystals with super-fine grain size, and paves the way for future development. 相似文献
16.
Single crystals of hexagonal structure Mn2P are synthesized by Sn flux for the first time. Transport and magnetic properties have been performed on the single crystals, which is an antiferromagnet with Neel temperature 103 K.Obvious anisotropy of resistivity is observed below the Neel temperature, which is manifested by metallic behavior with a current along the C-axis and semiconducting behavior with a current along the α-axis. The negative slope of temperature-dependent resistivity ... 相似文献
17.
Nasser Metwally 《International Journal of Theoretical Physics》2008,47(3):623-633
A model of two 2-level atoms interacts with a single quantized electromagnetic field is considered. We study the effect of
the mean photon number and the structure of the initial states of the two atoms on the dynamics of the atomic system from
the separability point of view. It is found that, if we start from a product mixed atomic state, the probability of generating
long living entangled states is increased as the mean photon number increases. Starting from excited atomic system in product
state, one generates a more stable entangled states with high degree of entanglement. Also, the effect of the mean photon
number on atomic system prepared initially in entangled states is investigated. It is found that the entangled state generated
from the initially partial entangled states are more robust than those obtained from a maximum entangled state. The Pancharatnam
phase for the separable and entangled states is studied under the effect of the mean photon number and the structure of the
initial state. We find that for the separable states, the collapses decrease and the amplitude of the revivals is smaller
than that for the entangled state, so there are long-living entangled phases. This property give us a great chances to store
safely information in entangled state. 相似文献
18.
Hyperfine Interactions - The distribution of C and N atoms in the octahedral interstitial sites of the face-centred-cubic austenite phase of the Fe–C and the Fe–N alloys is... 相似文献
19.
20.
Borik M. A. Volkova T. V. Kulebyakin A. V. Kuritsyna I. E. Lomonova E. E. Myzina V. A. Milovich F. O. Ryabochkina P. A. Tabachkova N. Yu. Zentsova A. I. Popov P. A. 《Physics of the Solid State》2020,62(1):235-239
Physics of the Solid State - The temperature dependence of the thermal conductivity of cubic ZrO2 single crystals stabilized with yttrium oxide from 8 to 40 mol % has been studied in the... 相似文献