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间-硝基苯胺(m-NA)C_6H_6N_2O_2晶体解理面(040)有很高的衍射强度,其衍射峰值强度是常用的X射线分光晶体季戊四醇(PET)峰强的2~3倍,预计m-NA晶体可能是一种优良的X射线分光晶体。 相似文献
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软X射线分光晶体马来酸氢十八酯 总被引:1,自引:1,他引:0
马来酸氢十八酯(OHM)是一种大晶面间距(2d=63.5A)X射线分光晶体,在适用的波长范围内。其X射线衍射性能优于硬酯酸铅皂膜假晶体(STE),晶体的物理化学性能稳定、机械强度好、易于加工。业已证明OHM晶体是一种软X射线理想的单色器。 相似文献
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根据同步辐射光源对软X射线分光晶体的性能要求,分析了软X射线能区常用分光晶体的性能优劣,指出对于晶格常数值大的分光晶体,KTP(KTiOPO4)(011)是该能区比较理想的分光晶体. 同时提出了一种利用同步辐射光源测量晶体衍射效率的实验方法,指出光源的发散度与晶体的衍射效率密切相关. 测量了KTP(011)晶体的晶格常数,给出了KTP(011)晶体的实测衍射效率.
关键词:
同步辐射
KTP(011)晶体
衍射效率
光源发散度 相似文献
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程晋明傅华叶雁曹宇东阳庆国 《高压物理学报》2016,(5):353-357
由于炸药具有弱吸收特性,利用传统的X射线成像技术难以获得质量较好的图像,因而无法对炸药内部的微小缺陷进行诊断。为提高炸药的X射线成像质量,采用X射线同轴相衬成像方法,获得了不同压力作用下高聚物粘结炸药(PBX)内部缺陷的一系列X射线相衬图像,从中清楚地观察到炸药内部缺陷从无到有、从小到大的准静态扩展过程,为研究高能炸药的热点形成机制提供技术支持。 相似文献
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氟化锂晶体具有较好的机械性能,容易加工,解理面具有高的X射线衍射强度和良好的色散本领,所以是电子探针微区x射线谱仪和荧光X射线谱仪的主要分光晶体之一.分光晶体质量的好坏直接影响仪器的性能.因此对分光晶体的质量进行检测是十分必要的. 氟化锂作为一种典型的晶体许多人进行过研究.很早 Gilman和Johston[1]等曾用化学浸蚀法.Yoshimatsu Newkirk等[2,5]曾用X射线形貌术研究过位错和亚晶界.Birks和 Seal[6]曾用X射线方法研究过研磨、淬火和弯曲等工艺对LiF分光晶体衍射峰值强度和半高宽的影响. 本文提出用X射线衍射形貌技术和X射线… 相似文献
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X射线吸收谱研究碳与硅的纳米线/管 总被引:1,自引:1,他引:0
由于X射线吸收谱中的总电子产额(TEY)和荧光产额(FLY)具有不同的取样探测深度,分别对样品的表面和体内敏感,因而两者的综合应用为纳米材料的整体分析提供了有力的依据,是透射电子显微镜(TEM)、X射线衍射(XRD)等传统方法分析纳米材料时的补充。同时,通过对TEY和FLY记录的X射线吸收谱的评述,作者认为X射线吸收谱可以准确、可靠地用来进行纳米线和纳米管的生长及其机理、取向、化学键合、缺陷与螺旋性等方面的研究。因此X射线吸收谱具有传统方法无法比拟的优势,是纳米材料研究领域强有力的表征工具。 相似文献
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Polycrystalline monazite (monoclinic LaPO4) was deformed by spherical indentation at room temperature. Slip systems were identified using TEM of thin sections prepared parallel and close to the indented surface. Dislocation Burgers vectors (b) were identified by Burgers circuit closure in high resolution TEM images, supplemented by diffraction contrast where possible. A total of 441 b determinations were made in 97 grains. The most common slip systems were [001]/(010), [100]/(010) and [010]/(100). Slip on (001) was less common. Many other less common slip systems and Burgers vectors were also identified, including b = [101], [101], [011], [110] and [111]. b = [101] dislocations dissociate into ½[101] partials, and b = [101] dislocations are inferred to dissociate to ½[101] partials, with a low energy stacking fault of ~30 mJ/m2. b = [100] dislocations may dissociate into ¼[210] + ¼[210] partials. b = [010] may sometimes dissociate to ½[010] + ½[010] partials. Other types of partial dislocations were also observed and discussed. All partial dislocations were climb dissociated. The line energies of monazite dislocations and their partials were calculated, and stacking fault structures for partial dislocations are analyzed. Satisfaction of the Von Mises criterion for full ductility most likely involves [101]/(111) and ?011?/{011} or {111} slip, but other combinations that require both b = [101] and ?011? or ?110? are possible. If deformation twinning is active, slip systems with b = ?011? or ?110? may not be necessary for full ductility. 相似文献
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电解纯铜经88.7%冷轧后,所形成的轧制织构除稳定的(110)[112]舆(112)[111]外,还存在着一种(3,6,11)[533]织构。在较低温度下退火时,再结晶织构主要为(100)[001]、(358)[352]和舆(100)[001]成孪生取向的(122)[212]织构。随着退火温度的增加,(358)[352]织构逐渐减弱,立方织构(100)[001]则逐渐加强;当退火温度达到900℃时,开成了集中的(100)[001]织构。冷轧铜板在退火的过程中,具有(100)[001]再结晶晶粒首先形成,然后普遍地发生同位再结晶。其中具有(100)[001]取向的晶粒,继续发生选择性的生长,最后形成了集中的立方织构。本支中对轧制织构舆其再结晶织构取向间的关系也进行了分析,再结晶织构一般可认为是原有织构沿某一个[111]轴旋转45°,22°或38°的结果。同时,根据上述几何关系所绘出的理想极图舆实际测定的结果也是符合的。试验结果指出,不同加热速度和不同加热程序对形成最终的再结晶织构,不发生显著的影响,而退火温度对再结晶织构的形成起着主要的作用。 相似文献
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《Journal of Macromolecular Science: Physics》2013,52(5):869-911
Isothermal polymerization of acetaminobenzoic acid at various temperatures in bulk and solution was monitored by acetic acid evolution. The polymerization took place initially in a homogeneous phase, but it soon changed to heterogeneous as the polymer precipitated from the melt or solution. The reaction course consisted of a short induction period, followed by a fast second-order reaction and a third slow, also second-order, reaction. The different polymerization rates in the second and third stage were due to polymer precipitation. The degree of polymerization of the resulting polymer was generally low, usually less than 5. The polymer was highly crystalline and prone to decarboxylation at temperatures above 300°C. Sample structure and morphology were characterized by various lamellar formations similar to those seen previously in many aromatic polyesters. Epitaxial solution polymerization/crystallization on mica resulted in three different morphologies, the most unique being shish kebab–type structures. Polybenzamide [poly(p-aminobenzoate)] is polymorphic; the most frequently seen hk0 electron diffraction patterns were similar to those from phase I of aromatic polyesters. Phase II of polybenzamide was seen only rarely. Simulation, using Cerius2, suggested equal agreement with [001], [100], and fiber electron diffraction (ED) patterns and X-ray powder patterns for two different orthorhombic unit cells (a = 7.71, b = 5.35, c = 12.94 Å, ρ = 1.55 g/cm3); both have a parallel packing of adjacent molecules, but in one, successive phenyl rings along a given chain are parallel, while in the other they are twisted at ±30°. For both unit cells, neighboring molecules were displaced by ±0.14 Å along c to obtain better agreement with the observed patterns. The [010] patterns could distinguish between the two cells, but were not obtainable. 相似文献
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The near-interface region of an epitaxial Ba0.3Sr0.7TiO3 thin film grown on LaAlO3 (001) was found to consist of a high density of ½?110? stacking faults bounded by partial dislocations. The stacking faults can extend over large distances (greater than 50 nm). Various possible atomic configurations of the faults were considered. The atomic structures of the faults were identified using high-resolution electron microscopy and simulation as well as energy-filtered imaging. The ½[101] and faults (where [001] is normal to the film plane) were found to lie predominately on the {100} and {110} planes. The ½lsqb;101] faults on (010), (110) or (1&1tilde;0) have never been observed before in perovskites. The stacking faults on [100] have a structure consisting of a double layer of edge-sharing TiO6 octahedra. The excess of Ti was detected by energy-filtered imaging. The formation of the extended stacking faults is probably related to a small amount of excess Ti during the film deposition, which may originate from the non-stoichiometry of the ceramic targets BaTiO3 and SrTiO3. It is also enhanced by the misfit-induced compressive strain in the early stages of the film growth. 相似文献
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应用分子动力学方法,采用嵌入势模型在熔点下和熔点上对Al(001),(110)和(111)表面的原子结构和自扩散现象进行研究.发现这些表面的第一层原子在低于熔点时,Al(110)面在700±10 K,Al(001)面在 860±10 K,Al(111)面在 930±10 K呈现明显自扩散且最终转变为"类液"结构,而其余各层仍保留有序状态.对这种"类液"结构进行均方位移、结构有序参数、径向分布函数和z向粒子密度分析,发现其结构和扩散行为与熔化的Al表面不同,并能在一定温度区间稳定存在.在"类液
关键词:
表面结构
分子动力学
自扩散 相似文献
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Integral yields of spontaneous emission at wavelengths of 1.73, 2.03, and 2.65 μm have been measured upon excitation of pure xenon by a pulsed electron beam. These yields have been analyzed and experimental data have been obtained on time constants of radiative transitions 5d[3/2]1 → 6p[5/2]2, 5d[3/2]1 → 6p[3/2]1, and 5d[3/2]1 → 6p[1/2]0 of XeI, which appeared to be equal to (2300 ± 400) × 10?9, (300 ± 40) × 10?9, and (1300 ± 200) × 10?9 s, respectively. It is shown that the experimental data are in a qualitative agreement with the results of computational and theoretical investigations. The results of averaging the experimental and calculated data are proposed for use as recommended values of the corresponding constants. 相似文献
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Yozo Chatani Toshio Uchida Hiroyuki Tadokoro Koichiro Hayashi Masanobu Nishii Seizo Okamura 《Journal of Macromolecular Science: Physics》2013,52(4):567-590
An X-ray study has been applied to clarify the relationship between crystal structures and crystal orientations of tetraoxymethylene and polyoxymethylene obtained by solid- state polymerization of tetraoxymethylene. The polyoxymethylene crystal obtained by the solidstate polymerization of a tetraoxymethylene single crystal was found to be definitely oriented with respect to the original tetraoxymethylene single crystal without any aftertreatment; i.e., the polymer chain (the c-axis) is parallel to the b-axis of tetraoxymethylene and the a-axis of polyoxymethylene coincides to the c-axis of tetraoxymethylene. In addition to the main orientation, other preferred crystalline orientations (“twin structure”) of polyoxymethylene were observed in polymers polymerized at lower temperatures (60-80°C); i.e., the polymer chains are parallel to either the [100], [001], or [101] direction of the original tetraoxymethylene crystal, though the amount of such oriented crystallites is small. The twin structure is different from that of polyoxymethylene obtained from trioxane. This difference is due to the crystal structures of these original materials; tetraoxymethylene occurs in the monoclinic system, while trioxane belongs to the trigonal system, as does polyoxymethylene. These characteristic orientations are explained in terms of the molecular arrangements in the crystals of the original materials. 相似文献
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K. E. G. Löbner 《Zeitschrift für Physik A Hadrons and Nuclei》1968,216(4):372-397
The half-lives of the following intrinsic states in deformed odd-mass nuclei has been measured by delayed coincidences with a time-to-amplitude converter:
- 5/2 5/2+[642] at 86.5 keV in155Gd:T 1/2=6.7±0.3 ns, which results in the determination of theE1,ΔK=1 transition probability to the ground state 3/2 3/2?[521] and first rotational state 5/2 3/2?[521], yielding hindrance factors ofF N ≈5.5 and ≈1.8 (F W =3.1×104 and 2.3×104) respectively.
- (3) 5/2 5/2?[512] at 191.4 keV in169Yb:T 1/2=3.35±0.15 ns and at 122.39 keV in171Yb:T 1/2=265±20 ns which results in the determination of the transition probabilities of theE1,ΔK=1 transitions to the ground states 7/2 7/2+[633], of theK-forbiddenM1 transitions to the 5/2 and 3/2 1/2?[521] and of theE2 transitions to the 5/2, 3/2 and 1/2 1/2?[521] states in both nuclei.
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《Surface science》1991,244(3):L125-L132
The carbon K-shell near edge X-ray absorption fine structure (NEXAFS) spectra of gas-phase ethylene molecules and ethylene adsorbed on Ag(100) have been calculated by the multiple scattering cluster method (MSC) for the first time. The calculated results show that carbon-hydrogen scattering resonances exist in the carbon K-shell NEXAFS spectra for both gas-phase ethylene molecules and ethylene adsorbed on the metal surface. By a comparison between the theoretical results and experimental spectra, we have found that ethylene molecules are adsorbed on the Ag(100) surface taking a four-fold hollow-site with the direction of the CC bond parallel to the [001] or [010] direction, the bond lengths of CC and AgC are equal to 1.40 ± 0.02 and 1.96 ± 0.03 Å, respectively. These results can be compared with that of the C2H4-Cu(100) system. 相似文献
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X. Zhang P. Berdahl A. Klini C. Fotakis S.S. Mao 《Applied Physics A: Materials Science & Processing》2008,91(3):407-410
We have synthesized 5 wt. %-yttria-stabilized zirconia (YSZ) films on stainless steel and glass substrates by pulsed laser
deposition (PLD) at substrate temperatures between 60 and 600 °C and oxygen pressures from 0.1 to 1000 mTorr. While highly
(101)-oriented tetragonal YSZ films are obtained at intermediate oxygen pressures, near complete (001)-oriented tetragonal
films are achieved at lower oxygen pressures, with a full width at half maximum X-ray peak of only 0.4°. The results can be
attributed to surface energy-induced orientation; that is, the lowest surface energy plane of the YSZ films changes from (101)
plane at intermediate pressures to the (001) plane at lower oxygen pressures due to surface relaxation.
PACS 81.15.Fg; 83.85.Hf; 68.55.jm 相似文献