Characterization of a Namban folding screen from the Edo period by means of EDXRF,SEM‐EDS and Raman spectroscopy

In this work, a multianalytical approach is employed to characterize the materials used in a Namban folding screen that depicts the arrival of the Portuguese to the port of Nagasaki. Portuguese sailors reached Japan in 1543 and initiated what was to be known as the Namban trade. This interaction between Portuguese and Japanese was meticulously recorded by artists in the form of valuable and rare folding screens. The present screen, attributed to the Edo period (~1603–1868), is what we could consider a second‐generation screen, a copy of scenes and characters that appear in screens from the Momoyama period (~1573–1603) but in increased scale and minor detail. The materials used in the screen were identified by means of in situ energy dispersive X‐ray fluorescence. Complementary results were obtained by Raman and scanning electron microscopy coupled to energy dispersive spectrometry analysis of microsamples taken from the screen. The palette used in this artwork resorts to gold, malachite, azurite, vermillion, red lead, white oyster shell, and carbon black. Differences were found, when compared with previously studied screens, i.e. the use of mixtures of pigments, namely vermillion with red lead in an orange shade of red and also the mixture of vermillion and carbon black to obtain a brown color. Special emphasis was given to the characterization of the golden areas and study of techniques of gold application. Copyright © 2013 John Wiley & Sons, Ltd.     

Determination of gold leaf thickness in a Renaissance illumination using a nondestructive approach

In this work, the thickness of the gold leaf applied in the Manueline foral charter of Murça (illuminated in 1512) will be determined using X‐ray fluorescence. In the frontispiece of the Manueline foral charter of Murça, the capital D was gilded using a gold leaf over a priming made of lead white. The characteristic lines of Pb (namely Lα and Lβ), although attenuated in the Au layer, are still visible in the X‐ray fluorescence spectra. By determining the intensity ratio Lα/Lβ and comparing it with the ratio for an infinitely thick sample, the thickness of the attenuating material can be determined. Using this methodology, the thickness of the gold leaf applied in the charter of Murça was estimated as 1.6 µm. Copyright © 2013 John Wiley & Sons, Ltd.     

Thickness and composition of gold and silver alloys determined by combining EDXRF‐analysis and transmission measurements

Energy‐dispersive X‐ray fluorescence (EDXRF)‐analysis is a technique which in the case of metals analyzes thin surface layers. For example, when gold and silver alloys are analyzed, it typically interests a depth of microns up to a maximum of tens of microns. Therefore, it can give wrong results or be affected by a large indetermination when the sample composition is altered because of surface processes, as often happens when silver alloys are oxidated, and sometimes in the case of gold alloys rich on copper or silver. A complementary technique was therefore developed, of bulk analysis, which uses the same equipment employed for EDXRF‐analysis; the X‐ray beam from the X‐ray tube is monochromatized by means of a tin secondary target, which K lines bracket the silver‐K discontinuity. The sample to be analyzed is positioned between the secondary target and the detector. This technique is able to determine (by measuring the attenuation of tin‐K rays) thickness and/or composition of gold and silver alloys having a thickness of less than about 120 µm for gold and about 0.7 mm for silver. The method was tested with Au–Ag–Cu alloys of known composition and thickness and then applied to gold and silver artifacts from the tomb of the Lady of Cao, which belongs to the Moche pre‐hispanic culture from the North of Peru, and dates about 300 A.D. Copyright © 2014 John Wiley & Sons, Ltd.     

辐射加热铝Ka吸收谱测量

 铝K_a吸收谱是诊断辐射加热等离子体温度的重要方法之一。在星光Ⅱ激光装置上，利用激光金膜相互作用产生的X光辐射加热其背侧的铝夹层样品，采用天津Ⅲ号胶片记录的PET晶体谱仪测量了不同激光和样品参数条件下的铝Ka吸收谱。实验观察到非常清晰的类氦到类氟铝离子Ka吸收谱线，采用细致组态模型开展了铝Ka吸收谱的模拟计算，模拟计算结果与实验结果符合得较好，研究结果可应用于辐射不透明度样品温度诊断。     

稀土离子注入的ZnS各种颜色发光二极管

ZnS单晶注入一种或两种稀土离子来制备发光二极管。本文研究了发光亮度与注入剂量的关系,发光亮度与电流的关系和发光亮度与温度的关系等。同时记录了电致发光和阴极射线发射光谱。选取两种不同的稀土离子注入到同一晶面,由于它们的比例不同,发光颜色可从一种稀土离子单独发光的颜色连续地改变到另一种颜色。     

基于PROSAIL模型的高寒冬季枯草关键参数阈值率定

冬季牧草即枯草的存量是生态补偿计算与畜牧生产科学管理的关键基础,而对青藏高原枯草关键参数认识的不足,直接限制了高寒冬季枯草监测研究与应用发展.PROSAIL是一种光学辐射传输模型,它可以定量描述植被参数与冠层反射率的关系.利用最新版本PROSAIL模型,结合野外实测的枯草光谱及叶面积、叶绿素等10个性状参数数据,模拟生...     

Packing density and optical properties of crt screens

Relations are derived which can be used to determine the thickness of crt screens and to determine the average size and packing density of the phosphor grains on the basis of light transmission by the screens. An experimental study was made for two phosphors: ZnS(Ag) and Al₂O₃(Ce).Translated from IzvestiyaVysshikh Uchebnykh Zavedenii Fizika, No. 10, pp. 98–103, October, 1970.     

The Bland–Altman analysis: Does it have a role in assessing radiation dosimeter performance relative to an established standard?

Bland–Altman analysis is used to compare two different methods of measurement and to determine whether a new method of measurement may replace an existing accepted ‘gold standard’ method. In this work, Bland–Altman analysis has been applied to radiation dosimetry to compare the PTW Markus and Roos parallel plate ionisation chambers and a PTW PinPoint chamber against a Farmer type ionisation chamber which is accepted as the gold standard for radiation dosimetry in the clinic. Depth doses for low energy x-rays beams with energies of 50, 75 and 100 kVp were measured using each of the ionisation chambers. Depth doses were also calculated by interpolation of the data in the British Journal of Radiology (BJR) Report 25. From the Bland–Altman analysis, the mean dose difference between the two parallel plate chambers and the Farmer chambers was 1% over the range of depths measured. The PinPoint chamber gave significant dose differences compared to the Farmer chamber. There were also differences of up to 12% between the BJR Report 25 depth doses and the measured data. For the Bland–Altman plots, the lines representing the limits of agreement were selected to be a particular percentage agreement e.g. 1 or 2%, instead of being based on the standard deviation (σ) of the differences. The Bland–Altman statistical analysis is a powerful tool for making comparisons of ionisation chambers with an ionisation chamber that has been accepted as a ‘gold standard’. Therefore we conclude that Bland–Altman analysis does have a role in assessing radiation dosimeter performance relative to an established standard.     

Scintillation efficiency and X-ray imaging with the RE-Doped LuAG thin films grown by liquid phase epitaxy

Very thin scintillator imaging plates have recently become of great interest. In high resolution X-ray radiography, very thin scintillator layers of about 5–20 μm are used to achieve 2D-spatial resolutions below 1 μm. Thin screens can be prepared by mechanical polishing from single crystals or by epitaxial growth on single-crystal substrates using the Liquid Phase Epitaxy technique (LPE). Other types of screens (e.g. deposited powder) do no reach required spatial resolutions. This work compares LPE-grown YAG and LuAG scintillator films doped with different rare earth ions (Cerium, Terbium and Europium). Two different fluxes were used in the LPE growth procedure. These LPE films are compared to YAG:Ce and LuAG:Ce screens made from bulk single crystals. Relative light yield was detected by a highly sensitive CCD camera. Scintillator screens were excited by a micro-focus X-ray source and the generated light was gathered by the CCD camera’s optical system. Scintillator 2D-homogeneity is examined in an X-ray imaging setup also using the CCD camera.     

Prediction of the spatial characteristics of higher mode sound transmission through a periodic slit screen

Periodic slit screens are often installed in rectangular apertures either to mask the opening or to reduce transmitted noise. This investigation considers the higher-order scattered and transmitted sound from a point source through a periodic screen mounted in a rigid baffle. In particular, this paper considers the spatial characteristics, or directivity, of the scattered field for a particular higher order mode. Uncoupled higher-order mode analysis is used to estimate the scattered and transmitted sound fields for the selected mode of the aperture without the presence of the screen. Transmission coefficients for the screens are then calculated using the well established equivalent mass layer effect and applied to the calculated higher-order mode scattered and transmitted sound pressures. Using an anechoic chamber, measurements were made over a small arc of the scattered sound field through a range of screens of different aspect ratios but the same porosity. The screens consisted of equally spaced open slits and solid laths and the number of slits was reduced to change the aspect ratio. In each case the point source was positioned on the impinging side of the aperture so as to drive one particular scattered higher-order aperture mode at or near cut-on. Comparison of the measured and predicted sound pressures indicate that good estimates of the sound field can be obtained through the approach of applying simple corrections for the presence of the screens to the estimates for the open aperture established using uncoupled calculations for the higher-order modes. It is also shown that the results for a specific mode excited at one particular frequency are applicable at other excitation frequencies provided that the correct non-dimensionalisation is applied.     

Self-connected horizontal silicon nanowire field effect transistor

We propose a technique to fabricate self-connected horizontal Si nanowire (NW) field effect transistors (FETs) by a self-assembly mechanism. We show direct growth of Si NWs between two predefined metallic electrodes along the SiO₂ gate oxide using the vapour–liquid–solid (VLS) growth mode. In our approach, the gold catalyst layer is covered by the contact metal, giving rise to selective and localized catalytic activity and growth of NWs from the gold edges. The diameter of the NWs can be adjusted by the thickness of the catalyst layer. Using such a process, we demonstrate field effect operation on the conductivity of a non-intentionally doped 20 nm diameter Si NW. This technique can be implemented in three dimensions, paving the way to three-dimensionalD integration using vertical stacks of self-connected FETs.     

On the creation of ordered nuclei by ion bombardment for obtaining nanoscale si structures on the surface of CaF<Subscript>2</Subscript> films

The effect of preliminary low-energy (~1 keV) and low-dose (~10¹²–10¹⁴ cm^–2) ion bombardment on the initial stages of growth of Si films on a CaF₂/Si surface is investigated. Ordered nanocrystal phases (thickness less than 5–6 monolayers) and homogeneous epitaxial nanofilms (thickness more than 8–10 monolayers) of silicon are shown to be formed after annealing.     

金纳米团簇组装的表面增强拉曼散射基底

表面增强拉曼散射(SERS)光谱技术是一种高灵敏度的检测技术，已在社会发展的多个领域显示出潜在的应用前景。SERS活性基底的大面积、低成本、可控制备是表面增强拉曼散射光谱学研究领域的热点之一。利用溶液法将直径小于5 nm的金纳米团簇旋涂成膜，调控退火温度和时间，将金纳米团簇融合组装成随机分布的金纳米岛。由于融合组装过程在150～210 ℃范围缓慢，控制条件可实现具有高密度增强“热点”的SERS基底，方法简单、成本低廉、面积大、均匀性高。我们利用该方法可重复性获得了性能优良的SERS基底。该基底对表面吸附的单分子层，具有强烈的表面增强拉曼散射光谱响应，150～210 ℃退火样品的宏观增强因子106～107量级。研究表明：相同条件下150～180 ℃退火，金纳米团簇首先融合成直径10～20 nm细小金纳米岛；退火温度190～210 ℃时，形成10～20 nm细小金纳米岛与50～70 nm金纳米岛混合并存的现象。拉曼光谱表征显示：大、小金纳米岛混合并存样品的宏观增强因子高于细小金纳米岛组成的样品。经220 ℃退火后，金纳米团簇完全融合成直径50～100 nm的金纳米岛，岛间距也随之增大，导致纳米岛之间的电磁场强度呈指数衰减，220 ℃退火的样品具有较低的增强因子。本论文揭示了金纳米团簇的缓慢自组装机制，分析了金纳米岛的形貌与表面增强拉曼散射光谱的关系，为该基底的应用研究奠定基础。     

基于BPLT模型的小麦叶片背景扣除方法的研究

为准确且无损测定小麦叶片的反射光谱,研究了不同背景对叶片表面反射光谱的影响,在400～1 000 nm波段范围测定了小麦叶片8种背景下的反射光谱以及叶绿素含量。以PLATE模型为基础,首次提出了BPLT(background plate)模型,扣除由不同背景导致的叶片反射光谱的变化。模型以背景下叶片的反射率R₀,不同背景反射率σ为输入,空气和致密叶片的界面反射比R₁₂,致密叶片和空气的界面反射比R₂₁,致密叶片的透射系数τ三参数中间变量,得到最终无背景时叶片反射率R值的2-3-1模型。采用方差分析法(analysis of variance, ANOVA)进行了BPLT模型验证,对比分析了背景扣除前后10种叶绿素指数值的变化。结果表明,当反演的确定系数DC(determination coefficients)>0.90且残差平方和SSE<1时,反演的灵敏度较高,对小麦叶片不同叶绿素浓度的背景扣除有着较好的效果;采用BPLT模型背景扣除后,背景因素所占的百分比低于5%;优选了NDI&MCARI的函数关系,NDI&MCARI的斜率和叶绿素浓度的R2由背景扣除前的0.847 4提高到背景扣除后的0.977 8。为真实测定不同背景下小麦叶片的反射光谱提供了依据。     

Structural and Optical Properties of Gold/Silica “Mushroom” Particles Prepared by Interfacial Templating

Complex shaped nanoparticles featuring structural or surface chemical patchiness are of special interest in both fundamental and applied research areas. This study reports the preparation and optical properties of gold/silica “mushroom” nanoparticles, where a gold particle is only partially covered by the silica cap. The synthetic approach allows precise control over the particle structure. The interfacial preparation method relies on partially embedding the gold particles in a polystyrene layer that masks the immersed part of the gold particle during silica shell growth from an aqueous solution. By adjusting sacrificial polystyrene film thickness and silica growth time, precise control over the coverage and cap thickness can be achieved. Correlative electron microscopy and single particle scattering spectroscopy measurements underline the high precision and reproducibility of the method. The good agreement between the measured and simulated single particle spectra supported by near‐field calculations indicates that the observed changes in the dipolar plasmon resonance are influenced by the extent of coverage of the gold core by the silica cap. The straightforward methods readily available for gold and silica surface modification using range of different (bio)molecules make these well‐defined nanoscale objects excellent candidates to study fundamental processes of programmed self‐assembly or application as theranostic agents.     

Investigation of the performance of an SPR-based optical fiber sensor using finite-difference time domain

Finite-difference time domain (FDTD) method was used to investigate the performance of surface plasmon resonance (SPR)-based optical fiber sensors. The results show that the performance of the fiber sensor can be optimized by choosing a proper combination of metal layer thickness of 40–60 nm and residual cladding thickness of 400–500 nm. Furthermore, the roughness effect of the gold surface layering the fiber sensor is significant in rough surfaces when sigma rms is greater than 5 nm or correlation length is lower than 100 nm.     

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应用不可分辨跃迁阵(UTA)模型结合相对论多组态Dirac-Fock方法,对金激光等离子体0.40～0.62nm范围内的带状谱和线状谱的主要特征参数进行了计算和分析,理论计算值和实验结果较之于单纯用UTA模型计算所得结果符合得更好。研究表明,对于谱线数目较少而又稀疏的跃迁,基于线谱的单独计算对UTA模型进行修正是合理和必要的。     

Matrix effects on the surface plasmon resonance of dry supported gold nanocrystals

We present a method to characterize surface-chemical properties of gold nanocrystals. Spherical, 60 nm gold nanocrystals were immobilized on quartz substrates by a coupling agent and cleaned in a hydrogen plasma. The nanocrystals were then functionalized with alkanethiol self-assembled monolayers (SAM) of varying chain lengths by adsorption from the gas phase, and localized surface plasmon resonance (LSPR) spectroscopy was performed on the samples. Depending on the alkanethiol chain length, the adsorption of the SAM redshifted the LSPR to different extents, in accordance with Mie theory. SAM thickness differences below 1 nm could be easily resolved. Our results demonstrate that LSPR spectroscopy can be applied to characterize thin organic layers on dry supported gold particles with high sensitivity.     

新药硫酸头孢匹罗的NMR研究

应用1D NMR、2D NMR （COSY、HMQC、HMBC、NOESY）及脉冲梯度场2D NMR技术[gHSQC（¹H-¹⁵N）、gHMBC（¹H-¹⁵N）]深入研究了第四代新型超广谱头孢菌素类抗生素硫酸头孢匹罗的结构,并首次对其¹H NMR、¹³C NMR谱和¹⁵N NMR谱的信号进行了全归属,通过NOESY实验对其立体结构提供有力依据.     

Simulation of thermionic emission optimization in femtosecond laser irradiation metal film by two-layer structure

The thermionic emission of the single-layer gold thin film and the two-layer film was assembled by gold padded with other metals (Ag, Cu, and Ni) and irradiated by the femtosecond laser pulse. Additionally, the emission was simulated by a two-temperature model combined with the Richardson–Dushman equation. It was found that the two-layer metal structure can change the electron temperature of the gold surface and control the thermionic emission compared with the single-layer gold film. With the same laser fluence, the two-layer film structure may shorten the duration of thermionic emission, and the duration of the thermionic emission can be further optimized by changing the proportion of thin film thickness with gold layer in the two-layer structure. The result can be especially beneficial in the context of ultrafast electron emission induced by femtosecond laser.