软 X射线共振非弹性光散射及其应用

软 X射线共振非弹性光散射是近年来随着高亮度第三代同步辐射出现而发展起来的光散射光谱技术 ,可以用于对多原子构成的分子、凝聚态物质进行位置选择的价电子态结构的研究。与 X射线光电子能谱 ( XPS)或紫外光电子能谱 ( UPS)相比 ,这一光谱方法由于测量样品激发后产生的散射 X射线 ,因而不仅可以获得表面的原子分子信息 ,而且可以用于研究样品体内或掩埋薄层的原子分子。同时这一方法的共振特性使得其可以进行灵敏的元素选择测量。本文将介绍这一光散射光谱技术及其在原子分子物理、表面物理及凝聚态物理中的应用     

模拟X射线热-力学效应电子束能谱的优化研究

实验室中主要采用电子束辐照来研究材料的热-力学响应规律,并以此为依据对材料抗核爆X射线的能力进行评估,此种评估方式忽略了电子束与X射线与物质相互作用中的差异,必然造成评估偏差。利用MCNP软件和约束最小二乘法,以1keV和3keV黑体X射线为优化对象,以电子束在介质中产生与X射线相同的能量沉积剖面为优化目的,对用于辐照铝、铜和钽三种材料的电子束能谱进行了优化计算,分别得到了它们的等效电子能谱。结果表明:等效电子能谱能够获得与相应的X射线一样的能量沉积剖面,可用作评估材料抗核爆X射线能力的依据;但等效电子谱与X射线和辐照材料均相关,应用中需依据辐照材料做出相应调整。     

时间积分透射光栅谱仪

本文简要介绍了使用中国科大首次研制成功的有聚酰亚胺衬底的透射光栅与北京电子学研究所研制的MCP(微通道板)构成的透射光栅谱仪,在功率密度～10~(14)W/cm~2的激光辐照条件下,成功地测到了平面Au、C、Al靶发射的软X射线能谱分布(相对值)和黑洞靶产生的软X射线能谱分布(相对值)。实验结果表明:用国内研制的透射光栅构成的时间积分透射光栅谱仪完全能用于激光等离子体实验。本文最后还提出了该设备的进一步改进方案。     

强激光辐照凹槽靶引起的高阶电离离子的丰度增强

高功率激光辐照固体靶时,靶面上的激光辐射场基本上可以与原子内壳层的电子束缚场相比拟。激光迅速地将元素大部分电子剥离从而产生高温高密度的等离子体并发射丰富的软X射线谱。当激光功率进一步提高时,等离子体的离子将进一步地被剥离、处激发态上的电子可能进一步被激发到更高的能级上并发射更为丰富、更强的X射线。     

HT-7电子加热实验的软X射线能谱诊断

介绍了HT-7装置上软X射线能谱诊断系统,用软X射线能谱对HT-7托卡马克上电子温度进行了测量。在离子伯恩斯坦波和低杂波协同实验中,观察到了对等离子体的较好的加热效果。     

电子辐照致VO_2(B)薄膜结构与红外光谱改变

本文以能量为1.0 MeV的电子束辐照VO2(B)薄膜,对电子辐照在薄膜中产生的缺陷进行了理论计算,使用X射线衍射仪、傅立叶中红外光谱仪对薄膜进行测试,分析了电子辐照对薄膜结构与红外光谱(3400~400 cm-1)的影响。结果显示:电子辐照可以在薄膜中引入点缺陷并产生退火效应,电子辐照在薄膜中引入的点缺陷,可以使V-O=V受到破坏,退火可以使V-O=V振动得到恢复,而电子辐照对薄膜八面体角度弯曲振动影响不大。     

硅漂移电子温度测量系统的研制

在磁约束聚变装置中，对等离子体电子温度的测量一般采用电子回旋辐射法（ECE）、汤姆逊散射法以及软X射线能谱法。其中软X射线（1～20keV）能谱法是一种传统的方法，它比汤姆逊散射法的测量误差小，且有较好的时空分辨；与电子回旋辐射法（ECE）相比较，时空分辨能力相近，但可作绝对测量，并且受超热电子和逃逸电子的影响较ECE小。在软X射线能谱法的应用中，过去使用Si（Li）探测器来探测软X射线能谱，Si（Li）探测器体积大，能量分辨和量子效率低，并且需要使用液氮冷却，大体积的杜瓦（通常35L）使探测器体积庞大，     

高温退火后非掺杂磷化铟材料的电子辐照缺陷

对不同气氛下高温退火非掺杂磷化铟(InP)材料的电子辐照缺陷进行了研究. 除铁受主外，磷化铁(FeP₂)气氛下退火后的InP中辐照前没有深能级缺陷，而辐照后样品的热激电流谱(TSC)中出现了5个较为明显的缺陷峰，对应的激活能分别为0.23 eV, 0.26 eV, 0.31 eV, 0.37 eV和0.46 eV. 磷(P)气氛下退火后InP中的热生缺陷较多，电子辐照后形成的缺陷具有复合体特征. 与辐照前相比，辐照后样品的载流子浓度和迁移率产生显著变化. 在同样的条件下，经FeP₂ 气氛下高温退火后的InP样品的辐照缺陷恢复速度较快. 根据这些现象分析了缺陷的属性、快速恢复机理和缺陷对材料电学性质的影响. 关键词： 磷化铟 电子辐照 缺陷     

丙酮稳定伽玛射线/紫外辐照下的水性氧化石墨烯

本文通过紫外可见光吸收光谱、X射线光电子能谱、电化学等方法证明丙酮能捕获和去除伽玛辐照产生的强还原性的水合电子. 在紫外线辐照过程中,丙酮的加入可能影响了电子的转移过程. 因此,丙酮可以用来稳定、调节GO的辐射还原过程.     

丙酮稳定伽玛射线/紫外辐照下的水性氧化石墨烯（英文）

本文通过紫外可见光吸收光谱、X射线光电子能谱、电化学等方法证明丙酮能捕获和去除伽玛辐照产生的强还原性的水合电子.在紫外线辐照过程中,丙酮的加入可能影响了电子的转移过程.因此,丙酮可以用来稳定、调节GO的辐射还原过程.     

Inhomogeneous depth distribution of fluorine atoms in PVDF upon radiative carbonization

Under the action of ionizing radiation on a PVDF film, fluorine and hydrogen atoms bound to its linear carbon chain with single chemical bonds detach. Free atoms and HF molecules diffuse toward the film surface and escape from it. As a result of irradiation of the sample surface, a fluorine concentration depth profile arises. The fluorine distribution in the PVDF films subjected to long-term X-ray exposure was studied using X-ray photoelectron spectroscopy and Rutherford backscattering spectroscopy. Both methods yield close values of the fluorine concentration at a depth of ～10 nm.     

Preparation and XPS study of X-ray photochromic transparent BiOI/nylon11 composite film

Nylon11 film immersed in BiI₃–ethanol solution was used for in situ generation of transparent BiOI/nylon11 X-ray photochromic composite materials via integration of the hydrolyzate (BiOI) of BiI₃ into nylon11. The obtained BiOI/nylon11 composite film shows a reversible photochromic effect, changing the color from orange-red to brownish black under soft X-ray irradiation and back to orange-red after air exposure. X-ray photoelectron spectroscopy (XPS) results show that the oxidation state of Bi atoms in BiOI/nylon11 composite film does not change before and after changing the color. Angle-resolved XPS analysis reveals that BiOI in nylon11 film is well distributed within an infiltration depth of about 10 nm. The source of the X-ray photochromic effect for transparent BiOI/nylon11 composite film may be related to oxygen as well as the interaction between BiOI and the amide groups. The oxygen AT% in the composite film decreases with increasing X-ray irradiation time. The present method for preparing transparent BiOI/nylon11 X-ray photochromic composite materials is facile and low cost. The X-ray photochromic effect has potential applications in some technology fields. For example, it can be used to create temporary patterning in a colored composite material surface.     

Effects of proton irradiation on structure of NdFeB permanent magnets studied by X-ray diffraction and X-ray absorption fine structure

The effects of proton irradiation on the structure of NdFeB permanent magnet were investigated by X-ray diffraction and X-ray absorption fine structure (XAFS). The results reveal that proton irradiation has no effect on the long-range structure, but significantly affects the atomic local structure of the NdFeB magnet. The alignment degree of the magnet decreases and the internal stress of the lattice increases after proton irradiation. XAFS results show that the coordination number of Fe-Nd in the first neighboring coordination shell of the Fe atoms decreases and the disorder degree increases.     

Surface Phase Transformations Induced on Fe0.86Mn0.14 by Carbon Ion-Irradiation

Conversion electron Mössbauer spectroscopy and X-ray diffraction have been used to investigate the modifications induced by room-temperature irradiation with 360 keV C^? ions on a Fe_0.86Mn_0.14 alloy. The data show that the irradiation produces γ-FeMn along with an increase in the amount of α-FeMn at the expense of ∈-FeMn, both originally present. The initial distribution of Mn atoms in the α-FeMn martensitic phase is observed to change after irradiation.     

非晶硅太阳电池的X射线辐照效应及其低能域光电流光谱观测

本文叙述氢化非晶硅(a-Si:H以下简称非晶硅或a-Si)太阳电池经不同剂量的X射线辐照后光电转换性能的变化情况,还用低能域(入射光子能量hv小于非晶硅光学能隙)光电流光谱法观测了经X射线辐照后,非晶硅太阳电池中局域能级的增加状况,为非晶硅太阳电池将来在航天技术中的应用提供实验数据,实验表明,X射线的辐照效应比可见光强得多,故它可以用来快速鉴定各种非晶硅太阳电池的长期稳定性。 关键词：     

PASSIVATION OF THE InP(100) SURFACE USING (NH4)2Sx

InP(100) surface treated with (NH₄)₂S_x has been investigated by using photolumines-cence(PL), Auger electron spectroscopy and X-ray photoelectron spectroscopy, It is found that PL intensity increased by a factor of 3.3 after (NH₄)₂S_x passivation and the sulfur remained on the surface only bonded to indium, not to phosphorus. This suggests that the sulfur atoms replace the phosphorus atoms on the surface and occupy the phosphorus vacancies.     

Visible-light-induced degradation of formaldehyde over titania photocatalyst co-doped with nitrogen and nickel

Titanium isopropoxide, ammonium carbonate and nickelous nitrate were used as the sources of titanium, nitrogen, and nickel to prepare titania photocatalyst co-doped with nitrogen and nickel by means of the modified sol-gel method. The photocatalyst was characterized by X-ray diffraction (XRD), UV-vis diffusive reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM). The prepared N-Ni co-doped photocatalyst showed optical absorption in the visible light area and exhibited excellent photocatalytic ability for the degradation of formaldehyde under visible light irradiation. The effects of annealing temperature and component on the phase composition and photocatalytic activity were investigated. The results demonstrated that nitrogen atoms was weaved into the structure of titania and led to the response to visible light. However, nickel atoms existed in the form of Ni₂O₃, dispersed on the surface of TiO₂, suppressed the recombination of photo-induced electron-hole pairs, raised the photo quantum efficiency, and led to the enhancement of photocatalytic performance. The increase of photoactivity was attributed to the synergistic effects of co-doping.     

InSb(111)表面硫处理的研究

本文用俄歇电子能谱、X射线光电子能谱和紫外光电子能谱对用硫化铵溶液处理的InSb表面进行研究。结果表明,硫处理以后在样品表面生成。一层厚度约8?的硫化物钝化层,它对防止表面的氧化和碳沾污有明显的钝化作用。钝化层中,破原子既与锑原子成键,引起Sb3d芯能级发生1.9eV的化学位移;又与铟原子成键,引起In4d芯能级发生0.6—0.7eV的化学位移。350℃的真空退火使锑的硫化物发生分解。500℃退火没能使铟的硫化物完全分解,仍有一部分硫原子以铟的硫化物形式留在样品表面。 关键词：     

纳米TiO_2-活性炭的制备及光催化脱汞初探

采用溶胶凝胶法以活性炭(AC)为载体,制备纳米TiO_(2-)活性炭复合物(TiO_(2-)AC).采用X射线衍射仪(XRD),场发射扫描电镜结合X射线能谱分析仪(FSEM-EDX)对TiO_(2-)AC复合物进行表征。在波长为253.7 nm的紫外光照射下进行TiO_(2-)AC光催化氧化脱除单质汞试验。结果表明,复合物表面TiO_2纳米粒子尺寸可控制在30 nm左右;热处理温度的升高促进TiO_2晶粒的生长及相变,复合物中TiO_2锐钛矿相向金红石相转变的温度在500～700℃之间;负载锐钛矿型TiO_2的复合物较金红石型复合物显示出更强的光催化脱汞效果。TiO_(2-)AC能够达到预期的结合TiO_2光催化氧化性能与活性炭强吸附能力的效果,脱汞性能显著,具有广阔的应用前景。     

COLORATION EFFECT OF PULSED LASER ON WO3

When laser pulses irradiate the surface of the sample WO₃, an interesting coloration effect is obtained. Only by one pulse of XeCl laser irradiation (wavelength: 308 nm, pulse duration: 36 ns, output power: 100 mJ/pulse), a significant color change appears. X-ray photoelectron spectroscopy (XPS) shows that a partial reduction process of WO₃ occurs and conduction band electrons appears. X-ray diffraction pattern indicates that the lattice parameters of the colored samples are increased. A molten layer can be seen in scanning electron microscopy (SEM) image. It may be concluded that the coloration effect of pulsed laser undergoes a process different from that of electro- or photo- chromism, and may be attributed to thermochromism and substoichiometric WO₃ is formed. The coloration process is characterized by its high speed and stability.