利用同步辐射形貌术研究晶体缺陷的实验方法探讨

利用同步辐射X射线形貌术研究晶体缺陷．是近年来发展起来的一种优良的实验方法．本文在研究LNP等晶体缺陷的同时,对这种实验方法进行了系统的探讨,讨论了散射光的消除、焦距的选择、样品的透明度与厚度、曝光的时间、底片的冲洗答问题．以及在缺陷研究中对晶体衍射的劳厄斑点的选取依据．     

同步辐射在晶体缺陷研究中的应用

 同步辐射是由高能加速器所提供的具有多种优异光学性能的光源.同步辐射可提供从远红外到硬X光的连续波段的辐射,并且具有极高的光强度,以及高偏振度等性能,因而同步辐射在物理学、材料科学、化学、生物学以及矿物学等多学科的研究领域得到越来越广泛的应用.北京正负电子对撞机(BEPC)是一台高能物理与同步辐射应用兼用型的加速器.同步辐射实验区提供了若干条光束线及相应的实验站,为来自国内外的科学工作者服务.其中最早投入运行、提供用户使用的是4W1A白光线及相应的X光形貌学实验站,用于对晶体缺陷及固体微结构的X光形貌研究.     

利用同步辐射确定晶体缺陷空间方位的方法

提出了利用同步辐射白光,采用异向入射成像技术,计算晶体缺陷空间方位的新方法.运用此方法研究了金刚石中的晶体缺陷,计算了位错的走向,确定了位错的类型和位错的三维分布特点.     

高压下的同步辐射X射线衍射研究

本文概要介绍了利用同步辐射Ｘ射线光源进行高压Ｘ射线衍射研究的现状及某些发展趋势．对金刚石压砧作为高压ｘ射线衍射的主要研究工具也作了介绍．本文还介绍了作者近年来在国外参加的百万大气压下的ｘ射线衍射研究中所取得的新进展．     

KTa1-xNbxO3晶体的同步辐射X射线白光形貌术研究

利用北京同步辐射光源，对居里点在室温附近的掺铁钽铌酸钾光折变晶体进行了Ｘ射线白光形貌术研究．观察显示，晶体内部除了杂质偏析物和一组沿［０１０］方向的生长层外，还有一组与之正交的畴组态，后者被发现不满足一般面缺陷的衬度消光规律，仅有异常散射效应揭示其衬度．利用同步辐射波长的可调谐性，揭示了该组畴随波长改变其衍时衬度变化的规律，而且畴的衍射强度被发现违背Ｆｒｉｅｄｅｌ定律．依据实验证据，这组畴被确认为１８０°铁电畴．对畴形成原因和晶体生长特性进行了讨论． 关键词：     

合肥同步辐射软X射线显微术研究

合肥国家同步辐射实验室首期建设的光束线之一用于软Ｘ射线显微成像研究。实验站现已装置初型的扫描透射Ｘ射线显微镜，并正在进行亲一代的扫描显微建设，同时还使同步辐射光进行接触软Ｘ射线呈微成像研究，并对选取的一些生物样品进行了成像试验。本文介绍了合肥同步辐射光源上软Ｘ射线显微术实验线站的建设及完成的一些实验结果。     

Image shifts resulting from the misorientation of two individuals in GdCa4O（BO3）3 crystal

Large GdCa4O(BO3)3 crystal has been grown by the Czochralski method.The quality of GdCa4(BO3)3 crystal was assessed by white-beam synchrotron radiation topography.It has been found that there is a sub-grain boundary in the GdCa4O(BO3)3 crystal.The boundary divides the large GdCa4O(BO3)3 crystal into two individuals.Due to the misorientation between the two individuals,the image shifts can be observed in the synchrotron topopraphs.Based on the misorientation determined by high resolution X-ray diffractometer,the image shifts were calculated for several reflections.The calculations are in agreement with the measurements from the topogrphs very Well.In addition,the formation mechanism of sub-grain boundary is discussed.2001 Elsevier science B.V.All rights reserved.     

同步辐射X射线衍射的谐波成分计算

结合动力学衍射公式和同步辐射谱,导出了衍射谐波的计算公式。作为应用的例子,计算了完美Si单晶常用的几个衍射晶面的同步辐射X射线衍射的谐波成分。数据适用于北京正负电子对撞机同步辐射实验室形貌站(4W1A光束线)。结果表明:(333)衍射中谐波成分丰富,而其它衍射中谐波成分较弱。 关键词：     

北京同步辐射实验室X光形貌学研究的光源特性及实验应用

本文讨论了北京同步辐射实验室X光形貌站相应的光源特性,给出了在该状态下的形貌分辨率以及对四硼酸锂晶体白光形貌衍射强度的计算结果.     

钼酸钆晶体畴结构的同步辐射白光形貌实时研究

用同步辐射白光X射线形貌术对畴结构在温度及外加电场变化条件下的演变情况进行了研究.结果表明:在钼酸钆样品中同时存在铁电畴和铁弹畴,但这两类畴在温度高于居里温度时都消失,当施加足够外加电压时可以单畴化.     

同步辐射软X射线显微成像

软X射线显微成像是同步辐射最主要的应用之一,本文简明介绍软X射线显微成像的衬度机制,光源,成像方法和一些应用结果。     

新型蓝光衬底材料LiAlO_2晶体的生长和缺陷分析

ＬｉＡｌＯ２和ＧａＮ的晶格失配率只有１．４％，是一种很有希望的ＧａＮ外延生长衬底材料。本文利用温度梯度法生长出了透明的ＬｉＡｌＯ２单晶，并通过化学浸蚀、光学显微镜、透射电子显微镜、同步辐射Ｘ射线貌相术对晶体中的缺陷进行了检测。结果表明：ＬｉＡｌＯ２在钼坩埚中无籽晶自由凝固结晶时，是沿（１００）方向生长。用温度梯度法生长的ＬｉＡｌＯ２晶体质量良好，晶体中无气泡和包裹物。在ＬｉＡｌＯ２（１００）晶面上测得的位错密度为（３．８～６．０）×１０４ｃｍ－２，晶体中的主要缺陷为亚晶界或镶嵌结构，可能是由于温场不稳定、生长速率太快造成的。     

SPIO–RGD nanoparticles as a molecular targeting probe for imaging tumor angiogenesis using synchrotron radiation

Angiogenesis, new blood vessels sprouting from pre‐existing vessels, is essential to tumor growth, invasion and metastasis. It can be used as a biomarker for early stage tumor diagnosis and targeted therapy. To visualize angiogenesis many molecular imaging modalities have been used. In this study a novel X‐ray molecular targeting probe using superparamagnetic iron oxide (SPIO) conjugated with arginine–glycine–aspartic acid (SPIO–RGD) has been developed. Based on the extremely high sensitivity to the iron element of synchrotron radiation X‐ray fluorescence and the superior spatial resolution of third‐generation synchrotron radiation, the feasibility of SPIO–RGD as a promising molecular probe for imaging tumor angiogenesis has been demonstrated.     

Bone‐nanohydroxyapatite spheres interface evaluation by synchrotron radiation X‐ray microfluorescence

Hydroxyapatite (HA) is largely used as bone graft; it seems to be the most promising synthetic implant material, mainly because of its excellent biocompatibility. The crystallinity, particle and pore size of HA are important characteristics and can be modified by decreasing basic structural form below 100 nm and have evoked a great amount of attention for improving prevention, diagnosis, and disease treatment, besides improving bone repair through the biodegradation of the material. The aim of this study was to investigate bone mineral content in bone samples with nanohydroxyapatite and HA spheres, specially its spatial distribution on bone microarchitecture. Circular bone defects were made in both tibiae of 12 White New Zeland adult rabbits (Oryctolagus cuniculus) and were divided randomly into five groups – blood clot (control group), sintered HA, non‐sintered HA, sintered nanoHA and non‐sintered nanoHA – all materials in spherical shape, to smooth handling and accommodation of the surgical bed, and to minimize inflammatory response. The rabbits were euthanatized according to the experimental period of 1 and 4 weeks after surgery. The samples were evaluated by polarized microscopy as well as X‐ray microfluorescence in order to account the bone mineral content bone‐implant interfaces, through synchrotron radiation. Our results revealed greater newly formed bone area in the non‐sintered materials and control groups, and the used technique showed that the amount of calcium of new bone was consistent with both mature bone and HA spheres. In conclusion, the present findings suggest that HA‐based biomaterials are biocompatible, promote osteoconduction and favored bone repair. Copyright © 2011 John Wiley & Sons, Ltd.     

同步辐射标定闪烁体探测器灵敏度

利用上海同步辐射光源BL13W1光束线开展了闪烁体探测器的灵敏度标定方法的研究。对光源的高次谐波以及闪烁体探测器的工作线性动态范围进行了实验研究,在此基础上建立了一种新的同步辐射标定闪烁体探测器灵敏度的方法。通过对实验结果的理论拟合,得到与放射源方法相符合的灵敏度数据,验证了方法的准确性,提高了标定数据的精度。     

The contribution of Neutron and synchrotron radiation topography to the investigation of first-order magnetic phase transitions

Neutron and white beam synchrotron topography have proved to be valuable and complementary tools for the investigation of the coexistence of magnetic phases in single crystals. Neutron topographs indicate unambiguously which phase occupies a given region of the sample, whereas synchrotron radiation topographs give information about the coexistence-related lattice distortion and the dynamics of the phase transition. A few examples illustrate these capabilities. 1) Helimagnetic-ferromagnetic coexistence was followed in Tb and MnP by varying either the magnetic field or the temperature. The observed interfaces appear to result from competition between the elastic and magnetostatic terms of the total energy, the last term being dominant in the field-driven case. 2) The reorientational transition of hematite was shown to correspond, when spread over a wide temperature range, to a succession of abrupt transitions, probably related to an inhomogeneous incorporation of small amounts of impurities during growth. A similar feature also explains the occurrence of small ferromagnetic islands which remain in the helimagnetic phase of Tb.     

IKNO,a user facility for coherent terahertz and UV synchrotron radiation

IKNO (Innovation and KNOwledge) is a proposal for a multi‐user facility based on an electron storage ring optimized for the generation of coherent synchrotron radiation (CSR) in the terahertz frequency range, and of broadband incoherent synchrotron radiation ranging from the IR to the VUV. IKNO can be operated in an ultra‐stable CSR mode with photon flux in the terahertz frequency region up to nine orders of magnitude higher than in existing third‐generation light sources. Simultaneously to the CSR operation, broadband incoherent synchrotron radiation up to VUV frequencies is available at the beamline ports. The main characteristics of the IKNO storage and its performance in terms of CSR and incoherent synchrotron radiation are described in this paper. The proposed location for the infrastructure facility is Sardinia, Italy.     

同步辐射探测器的应用与发展

探测器是同步辐射实验的重要环节。探测器水平必须不断提高才能适应同步辐射发展的需求，最大限度地发挥先进光源为人类研究提供的强大支持作用。文章介绍了当前同步辐射实验中普遍使用的各种探测器的原理和特点，并就一些新型探测器的发展情况进行了阐述。     

同步辐射探测器的应用与发展

探测器是同步辐射实验的重要环节。探测器水平必须不断提高才能适应同步辐射发展的需求,最大限度地发挥先进光源为人类研究提供的强大支持作用。文章介绍了当前同步辐射实验中普遍使用的各种探测器的原理和特点,并就一些新型探测器的发展情况进行了阐述。     

Diffractive–refractive optics: (+,−,−,+) X‐ray crystal monochromator with harmonics separation

A new kind of two channel‐cut crystals X‐ray monochromator in dispersive (+,?,?,+) position which spatially separates harmonics is proposed. The diffracting surfaces are oriented so that the diffraction is inclined. Owing to refraction the diffracted beam is sagittally deviated. The deviation depends on wavelength and is much higher for the first harmonics than for higher harmonics. This leads to spatial harmonics separation. The idea is supported by ray‐tracing simulation.