Influences of Al doping concentration on structural, electrical and optical properties of Zn0.95Ni0.05O powders

Nanocrystalline Zn0.95 - xNi0.05AlxO (x = 0.01, 0.02, 0.05 and 0.10) diluted magnetic semiconductors have been synthesized by an auto-combustion method. X-ray diffraction measurements indicate that all Al-doped Zn0.95Ni0.05O samples have the pure wurtzite structure. Transmission electron microscope analyses show that the as-synthesized powders are of the size 40 - 45 nm. High-resolution transmission electron microscope, energy dispersive spectrometer and X-ray photoemission spectroscope analyses indicate that Ni2+ and Al3+ uniformly substitute Zn2+ in the wurtzite structure without forming any secondary phases. The Al doping concentration dependences of cell parameters (a and c), resistance and the ratio of green emission to UV emission have the similar trends. (c) 2007 Elsevier B.V. All rights reserved.

Absence of room-temperature ferromagnetism in Al-codoped Zn0.95Co0.05O nanoparticles

Nanocrystalline Zn0.95-xCo0.05AlxO (x=0, 0.01, 0.05) diluted magnetic semiconductors have been synthesized by an auto-combustion method. X-ray diffraction measurements indicated that Al-doped Zn0.95Co0.05O samples had the pure wurtzite structure. X-ray absorption spectroscopy, high-resolution transmission electron microscope, energy dispersive spectrometer and Co 2p core-level photoemission spectroscope analyses indicated that Co2+ substituted for Zn2+ without forming any secondary phases or impurities. Resistance measurements showed that the resistance values of Co and Al codoped samples were still so large in the giga magnitude. Magnetic investigations showed that nanocrystalline Al-doped Zn0.95Co0.05O samples had no indication of room temperature ferromagnetism. (C) 2007 Elsevier B.V. All rights reserved.

Effects of CO2 laser conditioning of the antireflection Y2O3/SiO2 coatings at 351 nm

Y2O3/SiO2 coatings were deposited on fused silica by electron beam evaporation. A continuous wave CO2 laser was used to condition parts of the prepared samples at different scanning speeds in the air. LAMBDA 900 spectrometer was used to investigate the changes of the transmittance and residual reflection spectrum. A Nomarski microscope under dark field was used to examine the changes of the micro defect density. The changes of the surface roughness and the microstructure of the film before and after conditioning were investigated by AFM and X-ray diffraction, respectively. We found that laser-induced damage threshold (LIDT) of the films conditioning at 30 mm/s scanning speed was increased by more than a factor of 3 over the thresholds of the as-deposited films. The conditioning effect was correlated with an irradiation-induced decrease of the defect density and absorption of the films. (c) 2005 Elsevier B.V. All rights reserved.

Investigation on microstructure and optical properties of titanium dioxide coatings annealed at various temperature

TiO2 coatings were prepared on fused silica with conventional electron beam evaporation deposition. After TiO2 thin films were annealed at different temperatures for 4 h, several properties were investigated by X-ray diffraction (XRD), spectrometer.. photoelectron spectroscopy (XPS) and AFM. It was found that with the annealing temperature increasing, the transmittance of TiO2 coatings decreased, and the cutoff wavelength shifted to long wavelength in near ultraviolet band. Especially, when coatings were annealed at high temperature, the optical loss is very serious, which can be attributed to the scattering and the absorption of TiO2 coatings. XRD patterns revealed that only anatase phase was observed in TiO2 coatings regardless of the different annealing temperatures. XPS results indicated that the fine chemical shift of TiO2 2p(1/2) should be attributed to existence of oxygen vacancies around Ti+4 ion. The investigation on surface morphology by AFM showed that the RMS of titania thin films gradually increases from less than 0.40 nm to 5.03 nm and it should be ascribed to the growth of titanium dioxide grain size with the increase of annealing temperature. (C) 2005 Elsevier B.V. All rights reserved.

Stress, absorptance and laser-induced damage threshold properties of 355-nm HR coatings

A number of 355-nm Al2O3/MgF2 high-reflectance (HR) coatings were prepared by electron-beam evaporation. The influences of the number of coating layers and deposition temperature on the 355-nm Al2O3/MgF2 HR coatings were investigated. The stress was measured by viewing the substrate deformation before and after coating deposition using an optical interferometer. The laser-induced damage threshold (LIDT) of the samples was measured by a 355-nm Nd:YAG laser with a pulse width of 8 ns. Transmittance and reflectance of the samples were measured by a Lambda 900 spectrometer. It was found that absorptance was the main reason to result in a low LIDT of 355-nm Al2O3/MgF2 HR coatings. The stress in Al2O3/MgF2 HR coatings played an unimportant role in the LIDT, although MgF2 is known to have high tensile stress.

Study of Al2O3/MgF2 HR coatings at 355 nm

With the present work we tried to study the effective methods to improve the laser-induced damage threshold (LIDT) and reflectance of HR coatings at 355 nm. The work presented in this paper wits part of an ongoing study about vacuum annealing. It was dedicated to study the effects Of Vacuum annealing with different temperature gradients on the structure, optical properties and laser-induced damage threshold (LIDT) of 355nm Al2O3/MgF2HR coatings. A number of samples were prepared by electron beam evaporation using the same deposition process with an optimal deposition temperature of 280 degrees C. After deposition, samples were annealed in the coating chamber for 3 h with different temperature gradients. Morphologies of the samples were observed by Leica-DMRXE. Microscope, Structure of the samples had been characterized by X-ray diffraction (XRD). Transmittance and reflectance of the samples were measured by Lambda 900 Spectrometer, The LIDT of the samples was measured by a 355 nm Nd:YAG laser with a pulse width of 8 ns. It was found that the temperature gradient of vacuum annealing had significant effects on the morphology, structure, absorption, and LIDT of the samples, (c) 2005 Elsevier Ltd. All rights reserved.

Overcoat dependence of laser-induced damage threshold of 355 nm HR coatings

A series of HR coatings, with and without overcoat, were prepared by electron beam evaporation using the same deposition process. The laser-induced damage threshold (LIDT) was measured by a 355 nm Nd:YAG laser with a pulse width of 8 ns. Damage morphologies of samples were observed by Leica-DMRXE Microscope. The stress was measured by viewing the substrate deformation before and after coatings deposition using an optical interferometer. Reflectance of the samples was measured by Lambda 900 Spectrometer. The theoretical results of electric field distributions of the samples were calculate by thin film design software (TFCalc). It was found that SiO2 overcoat had improved the LIDT greatly, while MgF2 overcoat had little effect on the LIDT because of its high stress in the HR coatings. The damage morphologies were different among HR coatings with and without overcoats. (c) 2005 Elsevier B.V. All rights reserved.

脉冲激光辐照光学薄膜的缺陷损伤模型

建立了缺陷吸收升温致薄膜激光损伤模型，该模型从热传导方程出发，考虑了缺陷内部的温度分布以及向薄膜的传导过程，通过引入散射系数简化了Mie散射理论得出的吸收截面．对电子束蒸发沉积的ZrO2：Y2O3单层膜进行了激光破坏实验，薄膜样品的损伤是缺陷引起的，通过辉光放电质谱法对薄膜制备材料的纯度分析发现材料中的主要杂质元素为铂，其含量为0．9％．利用缺陷损伤模型对损伤过程进行了模拟，理论模型和实验结果取得了较好的一致性．

光学薄膜中界面层和表面吸附层对相位延迟的影响

多层介质反射镜在非正入射的时候，两个不同的偏振态之间会产生不同的相移．根据空气与膜层、膜层之间的实际情况，建立了界面层和表面吸附层模型，并运用它分析相位延迟产生误差的原因．通过优化设计，入射角为54°，在1285～1345nm之间p，s波获得了270±1°的相移，同时也使反射率在99．5％以上．用离子束溅射技术制备相位延迟膜，用分光光度计测试了光谱特性和用椭偏仪测试了相位特性，在相应波段获得了262．4±1．8°的相移，同时也使反射率在99．6％以上．误差的主要来源是离子源工作特性会产生不均匀的过渡层和最

Investigation on the properties of high reflective mirror prepared by ion-beam sputtering

The single-sided and dual-sided high reflective mirrors were deposited with ion-beam sputtering (IBS). When the incident light entered with 45 degrees, the reflectance of p-polarized light at 1064 nm exceeded 99.5%. Spectrum was gained by spectrometer and weak absorption of coatings was measured by surface thermal lensing (STL) technique. Laser-induced damage threshold (LIDT) was determined and the damage morphology was observed with Lecia-DMRXE microscope simultaneously. The profile of coatings was measured with Mark III-GPI digital interferometer. It was found that the reflectivity of mirror exceeded 99.9% and its absorption was as low as 14 ppm. The reflective bandwidth of the dual-sided sample was about 43 nm wider than that of single-sided sample, and its LIDT was as high as 28 J/cm2, which was 5 J/cm2 higher than that of single-sided sample. Moreover, the profile of dual-sided sample was better than that of substrate without coatings.

氧碘激光器相位延迟片的制备与性能研究

多层介质反射镜在非正入射的时候，两个不同的偏振态之间会产生不同的相移。利用矩阵法，根据菲涅耳公式和电磁场边界条件，推导出p，s波的相移。通过优化设计．入射角为54°，在1285～1345nm之间p，s波获得了270°±1°的相移，同时也使反射率在99．5％以上。用离子束溅射技术制备相位延迟膜，用分光光度计测试了光谱特性和用椭偏仪测试了相位特性，在相应波段获得了262．4°±1．8°的相移，同时也使反射率在99．6％以上。误差的主要来源是离子源工作特性会产生不均匀的过渡层和最外层会吸收一些水气、灰尘等也产生

反射式相位延迟器的性能研究

多层介质反射镜在非正入射的时候，两个不同的偏振态之间会产生不同的相移。通过优化设计，入射角为45°，在1285～1345nm之间p，s波获得了270°±0．15°的相移和99．5％以上的反射率。对使用的膜系进行了每层光学厚度的误差分析。用离子柬溅射技术制备相位延迟膜，在大气中对样品进行不同温度的退火，用分光光度计测试了光谱特性和用椭偏仪测试了相位特性。结果表明，未退火的样品在相应波段获得了267．5°±0．5°的相移和99．6％以上的反射率；根据拟合分析，最外层的误差和折射率与设计值的偏差是发生相移偏小的

基底对光学薄膜弱吸收测量的影响

对表面热透镜技术测量光学薄膜弱吸收低频调制时不同基底对测量的影响进行了理论分析。用Lambda-900分光光度计测量了K9和石英基底的Ti3O5单层膜的吸收值，将该组样品作为定标片；用表面热透镜装置分别测量了BK7和石英空白基底及HfO2，ZnO两组不同基底不同厚度单层膜样品的吸收。通过分析比较同一工艺条件下镀制的不同基底薄膜样品用与其同种和不同种基底定标片定标测量的结果，表明在低频测量时需要用与测量样品同种基底的定标片定标；不同厚度样品的测量结果表明，在不能严格满足热薄条件时，测量结果需引入修正值。

Working pressure dependence of properties of Al2O3 thin films prepared by electron beam evaporation

The effects of working pressure on properties of Al2O3 thin films are investigated. Transmittance of the Al2O3 thin film is measured by a Lambda 900 spectrometer. Laser-induced damage threshold (LIDT) is measured by a Nd:YAG laser at 355nm with a pulse width of 7ns. Microdefects were observed under a Nomarski microscope. The samples are characterized by optical properties and defect, as well as LIDT under the 355 nm Nd: YAG laser radiation. It is found that the working pressure has fundamental effect on the LIDT. It is the absorption rather than the microdefect that plays an important role on the LID T of Al2O3 thin film.

中国古牡丹资源调查及衰老相关研究

牡丹（Paeonia suffruticosa Andr.）是芍药科芍药属牡丹组植物，花大、色艳、型美、香郁、药用范围广、文化内涵丰富，被尊为“国色天香”、“花中之王”。我国植牡丹、赏牡丹有1600多年的历史，培育了许多价值高的品种，遗憾的是个别黄色、鲜红色、绿色等珍贵品种不断消失，而且现有的一些文化价值与观赏价值极高的古牡丹、著名的牡丹园的老牡丹均出现了衰弱现象，有的已奄奄一息。为了探索传统牡丹品种消失及牡丹衰老的原因，本研究在充分调查、整理国内品种资源的基础上，总结了牡丹品种的传承和消失情况，掌握了古牡丹的资源状况。通过连作土壤栽培试验证明了牡丹连作障碍的存在，并选定了生长在同一区域的5、10、15、20、25、30年生6个株龄的‘洛阳红（Luo Yang Hong）’为研究对象，从形态指标的调查、生理指标的测定、根际土壤及根系浸提液的化感成分分析三个方面着手，确定了牡丹开始衰老的时期;揭示了牡丹衰老机理;总结了古牡丹保留、复壮、养护办法;为牡丹专类园的管理及可持续性发展提供了理论和技术指导。本研究主要结果如下： 1、牡丹品种和古牡丹资源 通过对中国牡丹品种资源的文献查阅和实地考察，系统整理了我国不同时代的品种状况，调查结果表明：宋、元、明、清共有品种1109种，目前仅存143种，品种资源消失十分严重。收集整理了49处古牡丹资料，并据此绘制了我国目前古牡丹分布图;实地调查了17处24株古牡丹，详细介绍了部分品种的来历传说、生长状况和衰亡原因。5个优良传统品种在中国科学院植物研究所牡丹种质资源圃内得以保存，其中潞城古牡丹，植株最大（高2.3 m，冠径5.6 m），且生长旺盛;西溪牡丹属丰花品种，40年植株可开花811朵。 2、牡丹连作障碍 利用牡丹连作根际土壤及其浸出液栽培牡丹，结果表明，播种苗及分株苗的生长均受到了抑制;连作年限越久的处理抑制作用越强;根际土壤浸出液对牡丹生长的影响较大，对前期地下部和后期地上部都有很强的抑制作用，而且还抑制了上胚轴休眠的解除;根际土壤对后期株高和展叶幅的影响较大，对播种苗前期生根影响不大。牡丹存在连作障碍现象，连作障碍是牡丹衰弱的重要原因。 3、牡丹衰老时间及机理 通过对6 个株龄‘洛阳红’的形态、生理指标及根际土壤化感成分的比较得出，牡丹在同一地方大约栽植15 年后开始衰弱，20 年以内应该采取复壮措施。利用气相色谱—质谱联用技术（Gas Chromatograph-Mass Spectrometer, GC-MS）检测到根际土壤及根系浸提液中主要存在：烷烃、烯烃、芳香烃、醇、醚、酚醌、有机酸、醛、酮、酯、苯、胺等12 类有机物。对比分析得出有12 种物质可能是根系分泌物，根际土壤中可能具毒害作用的物质有40 种，栽植牡丹使土壤中增加的物质有24 种。 4、古牡丹复壮技术及应用 栽培基质中添加活性炭、沙子、麦饭石等均能有效的促进牡丹的生长，以活性炭的效果最好。对“汉牡丹”实施了综合复壮措施，效果明显。