紫外-真空紫外波段的Al+MgF_2膜

Al+Mg F2 膜是真空紫外波段常用的一种反射膜。根据薄膜光学的电磁场理论计算了正入射条件下 Al+Mg F2 膜在真空紫外波段的反射率随氟化镁膜厚度的变化规律。研究了 Al+Mg F2 膜的制备工艺 ,利用 Seya-Namioka紫外 -真空紫外反射率计测得 Al+Mg F2 膜的反射率在 1 50 nm～ 34 0 nm的波段上高于 80 %。Al+Mg F2 膜制备一年后 ,其真空紫外波段的反射率未有明显变化     

真空紫外反射率的测定

研制了一台测定真空紫外反射率的仪器.在真空紫外区可测量各种反射元件在不同入射角下的反射率.用壁稳氩弧光源在100—200um区对Al十MgF₂薄膜和CVD法制备的SiC镜的反射率进行了测定.并与Al膜的理论反射率曲线做了比较.     

真空紫外Al/MgF_2反射镜

采用三步热舟蒸发制作法研制了真空紫外Al/MgF2反射镜,研究了改善制备工艺有效提升反射率的方法。在两层Al/MgF2反射镜制备过程中,第一步在室温石英基板上快速蒸发厚约70nm的铝膜;第二步在铝膜表面迅速蒸发厚约10nm的MgF2;第三步先对基板加热到一定温度后,再在Al+MgF2的表面上蒸发15~20nm厚的MgF2。通过调整基板温度(室温、100℃、200℃和300℃),研究了基板温度对Al/MgF2反射率的影响。真空紫外反射率计测试结果表明:第二步蒸镀MgF2之后增加基板温度有利于提高反射镜的反射率;MgF2薄膜的厚度对反射镜的反射率起到一定的调制作用,MgF2厚为26.7nm的反射镜在122nm处的反射率达85%。在实验室环境下存放1个月和5个月后,反射镜的反射率没有变化。研究结果为真空紫外光学系统需求的高性能光学元件的研制提供了技术基础。     

计量线高次谐波的定量研究

采用自制的840/mm金膜自支撑透射光栅和美国IRD公司的AXUV100G光电二极管探测器,定量研究了光谱辐射标准和计量光束线在5~140 nm波段的高次谐波。研究了Al、Si₃N₄和Zr滤片在不同能量范围对高次谐波的抑制作用,给出了实验数据和曲线。实验结果显示:在5~15 nm波段,不用任何滤片高次谐波的信号强度＜7％;在5~34 nm波段,适当的选用Al、Si₃N₄和Zr滤片可有效地抑制高次谐波,将高次谐波占基波的积分信号强度比例控制在＜14％,经探测器的量子效率修正后高次谐波的百分比在6.5％以内。在经过MgF₂窗滤波的115~140 nm波段,高次谐波的衍射峰几乎完全被抑制。这一研究为软X射线和极紫外的光谱计量、探测器定标和光学元件性能测试奠定了基础。     

真空紫外空阴极气体放电光源

真空紫外空阴极光源是一种稳定的气体放电光源,工作气体为He、Ne、Ar、N₂、H₂、CO等,工作气压10torr～10^-2torr,工作电流100mA～400mA,能在20～200nm波段产生丰富的原子和离子谱线,光谱辐射稳定性优于±1%。     

软X线—真空紫外AI2O3光电二极管的研究

Al₂O₃光电二极管由于光谱响应波段较宽,性能稳定,经稀有气体电离室定标后,常用作软X线-真空紫外波段的光谱辐射传递标堆探测器。描述我们研制的Al₂O₃光电二极管的结构原理及Al₂O₃光阴极制备工艺,讨论性能测试方法与装置,给出测试结果。     

离化团束淀积光学薄膜实验装置的研制和性能实验

研制了离化团束淀积装置。目前的实验结果,使用离化团束淀积技术在玻璃冷基底上镀制的ZnS膜MgF₂膜的机械牢固性较电子束在同样条件下制备的ZnS膜和MgF₂膜较强。用反应性离化团束技术制备的ZnO膜具有优良的取向结构。通过控制参数可以控制ZnO膜的结晶结构。     

真空紫外波段Al膜保护层MgF_2的光学常数

由于Al膜的保护层MgF_2薄膜的光学常数对Al/MgF_2高反射镜的性能有极大的影响,本文研究了获取MgF_2薄膜光学常数的方法。用热舟蒸发的方法在室温B270基底上镀制了3块不同MgF_2厚度的Al/MgF_2反射镜样品,通过掠入射X射线小角反射方法表征样品,获得了膜层厚度和粗糙度。在国家同步辐射实验中心计量站测试了入射角为5°时,样品在105~130nm波段的反射率。在Al、MgF_2膜层的厚度和Al的光学常数已知条件下,依据菲涅尔公式,得出了满足某波长处样品反射率的等值曲线,然后从三条曲线的交点得出了MgF_2薄膜在108~128nm波段的光学常数。对比和分析显示:利用此方法得到的108~128nm波段MgF_2薄膜光学常数计算的反射率曲线和实际测试得到的反射率曲线吻合较好。     

一种设计真空紫外高反膜的新方法

在真空紫外强吸收波段采用"逐层"(LBL)设计法。通过阐述"逐层"设计的理论基础和膜材选择的基本原则,运用MatLab软件,用解析加复平面作图法设计了对应于50～200nm波段的高反膜系。以熔融石英基底上硅、碳组成的膜系为例,用这种设计方法获得的平均反射率最高可达64%。对比常规周期多层膜,这种设计法可以明显地提高强吸收波段的反射率。     

不同材料滤片对13~43 nm高次谐波的抑制

国家同步辐射实验室光谱辐射标准和计量光束线(U27)的SGM分支是专门为光学元件性能测试和探测器定标而建造的。为了能够精确测量光学元件在极紫外和软X射线波段的性能,必须充分抑制高次谐波提高光谱纯度。对于已经建成的光束线,要改变光学设计和现有结构来抑制高次谐波是困难的,最简单且有效的方法是用不同材料的滤片来抑制不同波段的高次谐波。为了研究高次谐波的抑制效果,可将840 l/mm透射光栅放在U27光束线SGM分支的出射狭缝后面色散出射光,用探测器做角度扫描记录下信号强度曲线,然后分析得到高次谐波的含量和分布。本文分别研究了不同厚度的Al(200、400和600 nm)、Si₃N₄/Mo/Si, Si₃N₄/Mo/Si/Mo/Si多层膜滤片(100/50/200 nm, 100/50/150/150/250 nm)和Al/Mg/Al 滤片对13~43 nm光谱高次谐波的抑制效果。 研究结果显示,400 nm厚的Al滤片适合于17~33 nm光谱高次谐波的抑制,在保证探测器信号强度的条件下,高次谐波信号强度占探测器信号强度的比例＜2％,经探测器量子效率修正后,高次谐波比例＜0.6％。Si₃N₄/Mo/Si/Mo/Si多层膜滤片可以有效地抑制13~19 nm的高次谐波,Al/Mg/Al滤片对30~43 nm的高次谐波有很好的抑制作用。这一结果为光学元件的透射率、反射率和探测器精确定标奠定了基础。     

反应性离化团束制备光学薄膜新技术

本文叙述了离化团束淀积光学薄膜的基本概念及特性,研制了离化团束淀积光学薄膜装置,开展了光学薄膜晶体结构与性能关系的研究。所研制的光学薄膜的牢固性相当好。基底不加温就可以得到ZnS、MgF₂的硬膜。反应性离化团束淀积的ZnO光学薄膜具有优良的织构,SiO₂光学薄膜呈现多晶结构。     

Characterization of nanoscale recording mark on Ge2Sb2Te5 film

We have fabricated nanoscale recording marks on Ge₂Sb₂Te₅ (GST) films with conductive atomic force microscope (AFM). GST films were deposited on glass or polyimide film with thickness of 150–200 nm by the rf–sputtering method. Through current–voltage (I–V) spectroscopy, good cantilevers for fabrication and characterization of nanoscale marks on GST were selected. A fresh and highly conductive tip showed voltage-switching characteristic in the I–V curve, where the threshold voltage was 1.6 V. Nanoscale dot and wire arrays of crystalline phases were successfully obtained by varying sample bias voltage from −10 to 10 V. With highly conductive tips, nanowires having full-width at half-maximum of 20 nm could be fabricated, whereas nanowires could not be fabricated with bias voltage below −2 V. The width of the nanoscale mark was increased by repetition of AFM lithography even with same applied voltage and lithography speed. For a thicker nanowire, the width measured in current-image (C-image) was observed to be 2 times of that measured in topography-image (T-image). This result supports that current sensing provides an image of phase-changed GST area with higher resolution than topography sensing.     

Mechanical properties and tribological behavior of ZrO<Subscript>2</Subscript> thin films deposited on sulfonated self-assembled monolayer of 3-mercaptopropyl trimethoxysilane

A silane coupling reagent (3-mercaptopropyl)trimethoxysilane (abridged as MPTS) was self-assembled on a single-crystal Si substrate to form a two-dimensional organic monolayer (MPTS-SAM). The terminal –SH group in the MPTS-SAM film was in-situ oxidized to –SO₃H group to endow the film with good chemisorption ability. Then ZrO₂ thin films were deposited on the oxidized MPTS-SAM by way of the enhanced hydrolysis of aqueous zirconium sulfate (Zr(SO₄)₂·4H₂O) in the presence of aqueous HCl at 50 °C, making use of the chemisorption ability of the –SO₃H group. The thickness of the ZrO₂ films was determined with an ellipsometer, while their morphologies and corresponding friction forces were analyzed by means of atomic force microscopy. The hardness and elastic modulus of the ZrO₂ thin films were determined on a Nanoindentation II (MET) instrument. The macro-friction and wear behaviors of the ZrO₂ films sliding against an AISI-52100 steel ball were examined on a unidirectional friction and wear tester and the worn surface morphologies observed on a scanning electron microscope (SEM). As the results, the as-deposited ZrO₂ thin film at a deposition duration of 100 h is about 100 nm thick, it decreases to 48 nm after annealing at 500 °C and further decreases to 45 nm after heating at 800 °C. The as-deposited ZrO₂ film is relatively rougher, with the rms to be about 1.0 nm, while the ZrO₂ thin films heated at 500 and 800 °C have surface roughness rms of 0.76 nm and 0.68 nm, respectively. The ZrO₂ film annealed at 800 °C has a high hardness to elastic modulus (H/E) ratio (0.062) as compared to the as-deposited ZrO₂ film and the film annealed at 500 °C. Both the two annealed ZrO₂ films show excellent wear-resistance as they slide against AISI-52100 steel at a normal load below 2.0 N, while the one annealed at 800 °C has better wear-resistance. The differences in the friction and wear behaviors of the as-deposited ZrO₂ film, the ZrO₂ film annealed at 500 °C and that annealed at 800 °C are attributed to their different micro structures and compositions. Since the ZrO₂ films was well adhered to the underlying MPTS-SAM, it might find promising application in the surface-protection of single crystal Si and SiC subject to sliding at small normal load in microelectromechanical systems (MEMS).     

全固态连续波555 nm黄-绿光激光器

报道了全固态连续波555 nm黄-绿光激光器,黄-绿激光分别由Nd:YAG和Nd:YVO₄晶体的946 nm和1342 nm谱线非线性和频产生,两条谱线各自晶体对应的能级跃迁分别为⁴F_3/2-⁴I_9/2和⁴F_3/2-⁴I13/2。实验中采用复合折叠腔结构,利用LBOI类临界位相匹配进行腔内和频,当注入到Nd∶YAG和Nd:YVO₄晶体的泵浦功率分别为12 W和8 W时,获得542 mW的TEM₀₀连续波555 nm黄-绿激光输出,4 h功率稳定度优于±3.7％。实验结果表明,采用Nd:YAG和Nd:YVO₄两种激光晶体进行腔内和频是获得黄-绿激光的高效方法,并可以应用到其它两种激光晶体进行腔内非线性和频,获得更多不同波长的激光输出。     

Sulfate based coatings for use as high temperature lubricants

Films of CaSO₄, BaSO₄, and SrSO₄ were grown with the pulsed laser deposition technique. The high temperature lubricious properties of these films were evaluated and it was found that all three sulfates exhibited a low coefficient of friction (μ ≈ 0.15) at 600°C. X-ray diffraction studies showed the presence of carbonate crystal structures along with the sulfate crystal structures after testing. The carbonate crystal structure is composed of alternating planes of alkali earth atoms and carbonate ions. The layered structure of the carbonates may be important to the lubricating mechanism as the layered structure of the dichalcogenides contributes to their tribological properties. Various observations of the wear region suggest that the starting surface finish of the metal coupon plays a significant role in the tribological mechanism of these materials. Additional composite films containing CaSO₄ were grown with the plasma spray technique. The high temperature friction properties of these films were measured and compared to those of similar films containing CaF₂/BaF₂. Although both types of films exhibited low coefficients of friction at 600°C, analysis of the wear regions did not show the presence of CaSO₄ and CaF₂/BaF₂, respectively. Ca and/or Ba were present, though, suggesting that a new compound is formed in the wear track and that the sulfate and fluoride phases may not be providing the low friction in these composites. This revised version was published online in July 2006 with corrections to the Cover Date.     

用锡盘抛光 α-Al2O3 单晶的初步实验研究

概述了抛光α-Al₂O₃单晶的意义、介绍了用锡盘抛光α-Al₂O₃单晶的实验装置、描述了抛光实验过程、研究了抛光时间和抛光液酸碱度对工件表面粗糙度的影响。通过改变抛光时间及抛光液pH值,可使α-Al₂O₃单晶工件表面粗糙度优于0.4nmrms.     

A study on friction and wear characteristics of nanometer Al2O3 /PEEK composites under the dry sliding condition

The friction and wear properties of the polyetheretherketone (PEEK) based composites filled with 5 mass% nanometer or micron Al₂O₃ with or without 10 mass% polytetrafluroethylene (PTFE) against the medium carbon steel (AISI 1045 steel) ring under the dry sliding condition at Amsler wear tester were examined. A constant sliding velocity of 0.42 m s⁻¹ and a load of 196 N were used in all experiments. The average diameter 250 μm PEEK powders, the 15 or 90 nm Al₂O₃ nano-particles or 500 nm Al₂O₃ particles and/or the PTFE fine powders of diameter 50 μm were mechanically mixed in alcohol, and then the block composite specimens were prepared by the heat compression moulding. The homogeneously dispersion of the Al₂O₃ nano-particles in PEEK matrix of the prepared composites was analyzed by the atomic force microscopy (AFM). The wear testing results showed that nanometer and micron Al₂O₃ reduced the wear coefficient of PEEK composites without PTFE effectively, but not reduced the friction coefficient. The filling of 10 mass% PTFE into pure PEEK resulted in a decrease of the friction coefficient and the wear coefficient of the filled composite simultaneously. However, when 10 mass% PTFE was filled into Al₂O₃/ PEEK composites, the friction coefficient was decreased and the wear coefficient increased. The worn scars on the tested composite specimen surfaces and steel ring surfaces were observed by scanning electron microscopy (SEM). A thin, uniform, and tenacious transferred film on the surface of the steel rings against the PEEK composites filled with 5 mass% 15 nm Al₂O₃ particles but without PTFE was formed. The components of the transferred films were detected by energy dispersive spectrometry (EDS). The results indicated that the nanometer Al₂O₃ as the filler, together with PEEK matrix, transferred to the counterpart ring surface during the sliding friction and wear. Therefore, the ability of Al₂O₃ to improve the wear resistant behaviors is closely related to the ability to improve the characteristics of the transfer film.     

单价银离子在 CaO-P2O5 系统玻璃中的发光特性

在弱还原气氛下制备了单价银离子(Ag⁺)掺杂的CaO-P₂O₅系统玻璃,测试了其在室温下的吸收光谱、激发光谱和发射光谱。Ag⁺-CaO-P₂O₅玻璃的吸收光谱表明两个吸收峰。高能峰位于220nm波长,由4d¹⁰→4d⁹5P¹跃迁引起,低能峰中心位于240nm波长,归因于4d¹⁰→4d⁹5s¹跃迁,该吸收与其发射特性有关。紫外波段的宽带吸收产生了可见波段强烈的荧光发射,发光峰位于440nm波长,半宽度为130nm.研究了掺质浓度与发光特性的关系,随着掺质浓度的增加(0.05～0.25mol%),发光峰向较长波段移动。在Ag₂O含量为0.5mol%时,出现了浓度猝灭现象。为了比较起见,同时还研制了Cu⁺-CaO-P₂O₅及Cu⁺-Ag⁺-CaO-P₂O₅玻璃。     

Design and Optimization of an Electrochemical Equipment for the Synthesis and Evaluation of Conducting Polymers

Abstract

A potentiostat system, focused towards the synthesis and evaluation of conducting polymers, was developed. This equipment consists of two main modules: the acquisition and control module, activated by means of a microcontroller which is connected through serial port to a computer, and the potentiostatic module, specially designed for handling the signals from the synthesis and characterization processes of the polymers. The user environment was programmed with Visual Basic 6. The resolution of the system AD/DA is of 12 bits; this allows sensibilities of 1 nA in current measurements. The achieved potential sweep is between ?2 and +2 V. By means of this equipment, ClO₄ ^?doped polypyrrole (PPy) and biphthalate doped PPy films were synthesized. The conducting polymers were synthesized by potential square waves. The thicknesses of the polymeric films were determined throughout the polymerization charge. The error percentage in the polymerization charge recorded by the developed potentiostat, relative to a commercial potentiostat, was about 6%. The ability to store the charge of the biphthalate PPy (biphthalate) films in potassium biphthalate aqueous solution was determined by cyclic voltammetry at various scan rates.