舰载光电跟踪系统φ1032mm窗镜的研制

针对舰载光电跟踪系统反射式主光学系统的防护问题,提出了一米量级尺寸的窗镜、镜框的设计、制造和检测的方法。首先,对窗口材料的性能及强度进行分析,依据内外压差、自身重量以及旋转惯性力对窗镜强度的影响确定其最小的厚度。其次,依据指标要求分析设计窗镜、镜框的形变对窗镜等光程差的影响以及其环境适应性。然后,采用等光程非平面的修磨方法对带镜框的窗镜进行加工及检测。最后,成功研制出直径φ1 032 mm,厚度80 mm,通光口径φ1 010mm的融石英材料的窗口玻璃镜,等光程差为RMS=0.062 8λ@632.8nm。结果表明,该窗镜能够对舰载光电跟踪系统反射式主光学系统进行有效的防护。     

隐形眼镜投影测量仪的设计

提出了一种采用光学投影成像和自扫描光电二极管列阵(SSPA)传感器实现隐形眼镜曲率、光学中心厚度和直径测量的新方法,基于此方法设计成功了一种新型隐形眼镜投影测量仪.介绍了仪器的测量原理、仪器结构、光电二极管列阵信号采集以及单片机控制系统的硬件和软件设计.该测量仪测量镜片曲率半径的精度优于±0.1mm,测量镜片光学中心厚度的精度优于±0.01mm,测量镜片直径的精度优于±0.1mm,并能分辨镜片上任何方向大于0.01mm的杂质和表面缺陷.     

A high pressure cell for dynamic light scattering up to 2 kbars with conservation of plane of polarization

We report on a high pressure cell with six optical windows which can be used up to 2 kbars for laser light scattering applications at scattering angles of 45 degrees , 90 degrees , and 135 degrees of liquid samples in a temperature range between -20 and 150 degrees C. The pressure transmitting medium is compressed nitrogen. The window material used is SF57 NSK, a glass with an extremely low stress optical coefficient in the order of about 10(-5) which allows thus to maintain the plane of polarization even under the action of high pressure. In order to demonstrate the functioning of the cell we show Rayleigh-Brillouin spectra of poly(methylphenylsiloxane) at different polarizations and pressures.     

In situ multipurpose time-resolved spectrometer for monitoring nanoparticle generation in a high-pressure fluid

We developed a multipurpose time-resolved spectrometer for studying the dynamics of nanoparticles generated by pulsed-laser ablation (PLA) in a high-pressure fluid. The apparatus consists of a high-pressure optical cell and three spectrometers for in situ measurements. The optical cell was designed for experiments at temperatures up to 400 K and pressures up to 30 MPa with fluctuations within ±0.1% h(-1). The three spectrometers were used for the following in situ measurements at high pressures: (i) transient absorption spectrum measurements from 350 to 850 nm to investigate the dynamics of nanoparticle generation from nanoseconds to milliseconds after laser irradiation, (ii) absorption spectrum measurements from 220 to 900 nm to observe the time evolution of nanoparticles from seconds to hours after laser ablation, and (iii) dynamic light scattering measurements to track nanoparticles with sizes from 10 nm to 10 μm in the time range from seconds to hours after laser ablation. By combining these three spectrometers, we demonstrate in situ measurements of gold nanoparticles generated by PLA in supercritical fluids. This is the first report of in situ time-resolved measurements of the dynamics of nanoparticles generated in a supercritical fluid.     

High-pressure cell for neutron reflectometry of supercritical and subcritical fluids at solid interfaces

A new high-pressure cell design for use in neutron reflectometry (NR) for pressures up to 50 MPa and a temperature range of 300-473 K is described. The cell design guides the neutron beam through the working crystal without passing through additional windows or the bulk fluid, which provides for a high neutron transmission, low scattering background, and low beam distortion. The o-ring seal is suitable for a wide range of subcritical and supercritical fluids and ensures high chemical and pressure stability. Wafers with a diameter of 5.08 cm (2 in.) and 5 mm or 10 mm thickness can be used with the cells, depending on the required pressure and momentum transfer range. The fluid volume in the sample cell is very small at about 0.1 ml, which minimizes scattering background and stored energy. The cell design and pressure setup for measurements with supercritical fluids are described. NR data are shown for silicon/silicon oxide and quartz wafers measured against air and subsequently within the high-pressure cell to demonstrate the neutron characteristics of the high-pressure cell. Neutron reflectivity data for supercritical CO(2) in contact with quartz and Si/SiO(2) wafers are also shown.     

High temperature faraday balance for in situ measurement of magnetization in transition metal oxides

We report the design of a Faraday balance that can be used to measure the magnetization of transition metal oxides at high temperatures and under controlled atmosphere. The instrument is sufficiently sensitive and stable to quantify the magnetic force on diamagnetic and paramagnetic samples at temperatures up to 1000 degrees C and in oxygen partial pressures as low as 100 ppm. We demonstrate the performance of the instrument by presenting preliminary magnetic measurements of lanthanum strontium cobalt oxide (La1-xSr(x)CoO3-delta) and aluminum oxide (Al2O3).     

A virtual experiment control and data acquisition system for in situ laser heated diamond anvil cell Raman spectroscopy

Doubled-sided laser heated diamond anvil cell methods allow simultaneous in situ confocal Raman measurements of materials up to megabar pressures and high temperatures. This paper describes a virtual control and data acquisition system developed to automate setups for simultaneous Raman/laser heating experiments. The system enables reduction of experiment time by ～90% in comparison to manual operations, allowing measurements of high quality Raman spectra of even highly reactive or diffusive samples, such as hydrogen at extreme conditions using continuous wave laser heating. These types of measurements are very difficult and often impossible to obtain in a manual operation mode. Complete data archiving and accurate control of various experimental parameters (e.g., on-the-fly temperature determination and self-adjusting data collection time to avoid signal saturation) can be done, and open up possibilities of other types of experiments involving extreme conditions.     

High-pressure and high-temperature x-ray diffraction cell for combined pressure, composition, and temperature measurements of hydrides

We present the design and construction of a high-pressure (200 bars) and high-temperature (600 °C) x-ray diffraction (XRD) cell for the in situ investigation of the hydrogen sorption of hydrides. In combination with a pressure, composition, and temperature system, simultaneous XRD and volumetric measurements become accessible. The cell consists of an x-ray semi-transparent hemispherical beryllium (Be) dome covering a heatable sample stage, which simultaneously allows sample temperatures of up to 600 °C in an applied hydrogen atmosphere of up to 200 bars. The system volume is as low as possible to maximize the precision of the volumetric measurements. Due to the high thermal conductivity of hydrogen, and in order to preserve the mechanical stability of the beryllium, the cell is water cooled. Its operability was studied on the example of the hydrogen absorption of Mg(2)Ni. The advantages and limitations of the proposed design are discussed.     

Cryogenic probe station for on-wafer characterization of electrical devices

A probe station, suitable for the electrical characterization of integrated circuits at cryogenic temperatures is presented. The unique design incorporates all moving components inside the cryostat at room temperature, greatly simplifying the design and allowing automated step and repeat testing. The system can characterize wafers up to 100 mm in diameter, at temperatures <20 K. It is capable of highly repeatable measurements at millimeter-wave frequencies, even though it utilizes a Gifford McMahon cryocooler which typically imposes limits due to vibration. Its capabilities are illustrated by noise temperature and S-parameter measurements on low noise amplifiers for radio astronomy, operating at 75-116 GHz.     

High pressure cell for Raman scattering at low temperatures

An optical cell suitable for Raman studies and for absorption studies of gases, liquids, and solids is described. The cell has been used at temperatures down to 4.2 K and pressures up to 10 kilobars. It contains a sample chamber with special scattering geometry and a ruby manometer for in situ pressure measurements. Typical results are given for the impurity induced one phonon Raman spectra of doped alkali halides and for the fundamental vibrational Raman spectra of matrix-isolated molecules under pressure.     

Ultra-high vacuum compatible image furnace

We report the design of an optical floating-zone furnace for single-crystal growth under ultra-high vacuum (UHV) compatible conditions. The system is based on a commercial image furnace, which has been refurbished to be all-metal sealed. Major changes concern the use of UHV rotary feedthroughs and bespoke quartz-metal seals with metal-O-rings at the lamp stage. As a consequence, the procedure of assembling the furnace for crystal growth is changed completely. Bespoke heating jackets permit to bake the system. For compounds with elevated vapor pressures, the ultra-high vacuum serves as a precondition for the use of a high-purity argon atmosphere up to 10 bar. In the ferromagnetic Heusler compound Cu(2)MnAl, the improvements of purity result in an improved stability of the molten zone, grain selection, and, hence, single-crystal growth. Similar improvements are observed in traveling-solvent floating-zone growth of the antiferromagnetic Heusler compound Mn(3)Si. These improvements underscore the great potential of optical float-zoning for the growth of high-purity single crystals of intermetallic compounds.     

Magnetic measurements at pressures above 10 GPa in a miniature ceramic anvil cell for a superconducting quantum interference device magnetometer

A miniature ceramic anvil high pressure cell (mCAC) was earlier designed by us for magnetic measurements at pressures up to 7.6 GPa in a commercial superconducting quantum interference magnetometer [N. Tateiwa et al., Rev. Sci. Instrum. 82, 053906 (2011)]. Here, we describe methods to generate pressures above 10 GPa in the mCAC. The efficiency of the pressure generation is sharply improved when the Cu-Be gasket is sufficiently preindented. The maximum pressure for the 0.6 mm culet anvils is 12.6 GPa when the Cu-Be gasket is preindented from the initial thickness of 300-60 μm. The 0.5 mm culet anvils were also tested with a rhenium gasket. The maximum pressure attainable in the mCAC is about 13 GPa. The present cell was used to study YbCu(2)Si(2) which shows a pressure induced transition from the non-magnetic to magnetic phases at 8 GPa. We confirm a ferromagnetic transition from the dc magnetization measurement at high pressure. The mCAC can detect the ferromagnetic ordered state whose spontaneous magnetic moment is smaller than 1 μ(B) per unit cell. The high sensitivity for magnetic measurements in the mCAC may result from the simplicity of cell structure. The present study shows the availability of the mCAC for precise magnetic measurements at pressures above 10 GPa.     

An apparatus for simultaneous thermodynamic and optical measurements, with large temperature excursions

We report the design and realization of an integrated system for measuring, at the same time, the thermodynamic and spectroscopic features of nanoporous materials interesting for hydrogen storage purposes. The whole investigation cycle, from thermal activation to the actual investigation of uptake and release of hydrogen, is carried out in the same vacuum tight vessel, equipped with an optical window, whose temperature can range between 10 and 750 K, up to a maximum pressure of 50 bars. The system has been designed to investigate properties of carbon nanotubes but its use can be extended to any kind of nanoporous sample such as, for example, carbon nanofibers, zeolytes, metal organic frameworks, and similar materials.     

Sample cell for EXAFS measurements on molten materials at elevated temperatures

We describe the design, fabrication, and utilization of a simple sample cell for extended x-ray absorption fine structure (EXAFS) measurements at elevated temperature. The cell is rigid, inert, easy to fabricate, cheap and effective in maintaining the critical specimen dimensions of both solid and liquid samples up to 1000 degrees C.     

Extreme nanomechanics: vacuum nanoindentation and nanotribology to 950 °C

Elevated temperature mechanical and tribological properties can be more relevant for practical wear situations than corresponding measurements at room temperature. However, high temperature nanomechanics and nanotribology is highly challenging experimentally. To overcome these challenges the NanoTest*** has been developed with active heating of the indenter and sample with resistive heaters, horizontal loading, patented thermal control method and stage design. By separately actively heating*** and controlling the temperatures of indenter and sample their temperatures can be precisely matched so that there is no heat flow and minimal/no thermal drift during the high temperature indentation,*** and measurements can be performed as reliably as at room temperature. Above 500 °C it is beneficial to use a cubic Boron Nitride indenter with gas purging to limit oxidation of samples. To achieve higher temperatures without indenter or sample oxidation an ultra-low drift high temperature vacuum nanomechanics/tribology system capable of testing to*** much higher temperatures has been recently developed (NanoTest Xtreme). The influence of time-dependent deformation on elevated temperature nanomechanical behaviour is discussed, using published results in Argon on glass-ceramic solid oxide fuel cell seal materials and previously unpublished nanoindentation measurements on single crystal silicon and polycrystalline tungsten using the NanoTest Xtreme in vacuum at temperatures up to 950 °C. Studies of the elevated temperature nano-/micro-tribological*** behaviour of wear-resistant*** nitride-based and MAX-phase coatings are also briefly reviewed.     

Quadrupole lenses on the basis of permanent magnets for a PRIOR proton microscope prototype

Four quadrupole lenses based on permanent magnets of the NdFeB material (PMQ) were developed for the imaging section for forming images of the ion-optical system of the PRIOR proton microscope prototype: the effective length of two of them is 144 mm, and the other two are 288 mm long. The field induction at the radius of the lens aperture is 1.77 Т, and the aperture is 30 mm in size. The modular design of the PMQ makes it possible to vary the length of the lenses, compensate for the offset of the magnetic axis from the ion optical axis of the microscope channel, and decrease the variation of the angular position of the magnetic medians. The PMQ magnetic field was adjusted, scanned, and its main characteristics were determined. The 3D mathematical models of the magnetic-field distribution that are obtained as a result of PMQ measurements are intended for the use in calculations of the beam dynamics during adjustment of the ion-optical system of the proton microscope and for attaining the highest spatial resolution. The developed lenses were used in the first experiments on the PRIOR facility.     

High-temperature multipass cell for infrared spectroscopy of heated gases and vapors

In absorption spectroscopy, infrared spectra of heated gases or condensed samples in the vapor phase are usually recorded with a single pass heated gas cell. This device exhibits two orders of magnitude lower sensitivity than the high-temperature multipass cell presented in this article. Our device is a novel type of compact long path absorption cell that can withstand aggressive chemicals in addition to temperatures up to 723 K. The construction of the cell and its technical features are described in detail, paying special attention to the mechanisms that compensate for thermal expansion and that allow the user to vary the optical path length under any thermal or vacuum condition. The cell may be used with a laser source or implemented within a Fourier transform infrared spectrometer. Its design is compatible with optical arrangements using astigmatic mirrors or spherical mirrors in a Herriott configuration. Here we implement a homebuilt Herriott-type cell with a total optical path length of up to 35 m. In order to demonstrate the feasibility of the cell, methane and water vapor absorption lines showing dissimilar temperature effects on line intensity were recorded with the help of a mid-infrared laser source tunable between 3 and 4 microm. Emphasis is put on lines that are too weak to be recorded with a single pass cell.     

Designing a miniaturised heated stage for in situ optical measurements of solid oxide fuel cell electrode surfaces, and probing the oxidation of solid oxide fuel cell anodes using in situ Raman spectroscopy

A novel miniaturised heated stage for in operando optical measurements on solid oxide fuel cell electrode surfaces is described. The design combines the advantages of previously reported designs, namely, (i) fully controllable dual atmosphere operation enabling fuel cell pellets to be tested in operando with either electrode in any atmosphere being the focus of study, and (ii) combined electrochemical measurements with optical spectroscopy measurements with the potential for highly detailed study of electrochemical processes; with the following advances, (iii) integrated fitting for mounting on a mapping stage enabling 2-D spatial characterisation of the surface, (iv) a compact profile that is externally cooled, enabling operation on an existing microscope without the need for specialized lenses, (v) the ability to cool very rapidly, from 600 °C to 300 °C in less than 5 min without damaging the experimental apparatus, and (vi) the ability to accommodate a range of pellet sizes and thicknesses.     

Improved Performance of Film-Riding Gas Seals Through Enhancement of Hydrodynamic Effects

Basic components of a spiral-groove, face-type gas seal are shown. Analyses of flow, of thermal environment and heat transfer were made to improve stability, decrease sensitivity to contaminants and reduce leakage. Analysis suggested reduced film thickness and the advantages of spiral-groove design over Rayleigh pad design for thin gas film operation. Experimental program started with static leakage tests to verify pressure deflections at various pressures; a 1000 h dynamic test followed where 114.3 mm (4.5 in.) diameter seals ran successfully at pressures up to 6.2 MPa (900 psig) and speeds up to 73.66 m.s.^?1 (14 500 fpm).