Manometer extension for high pressure measurement: nuclear quadrupole resonance study of Cu2O with a modified Bridgman anvil cell up to 10 GPa

We report (63)Cu nuclear quadrupole resonance (NQR) measurement of Cu(2)O under pressure up to about 10 GPa at low temperatures. Because the lattice parameter of Cu(2)O changes with increasing pressure, the electric field gradient at the Cu site also changes correspondingly with pressure. This enables us to use the Cu(2)O as an in situ manometer for high pressure nuclear magnetic resonance/NQR up to about 9 GPa.     

Measurement of thermoelectric power of solids up to 10 GPa

A method of measuring thermoelectric power of solids as a function of pressure up to nearly 10 GPa is described. A tungsten carbide opposed anvil setup is used to generate the pressure.     

大力开展“四达标”活动向设备管理要效益

中国长城铝业公司开展设备操作维护达标、设备检修达标、设备及环境卫生达标和设备台时产能达标的设备管理"四达标"活动,实行激励和约束机制,取得了非常显著的经济效益和社会效益.     

High pressure cell for neutron reflectivity measurements up to 2500 bar

The design of a high pressure (HP) cell for neutron reflectivity experiments is described. The cell can be used to study solid-liquid interfaces under pressures up to 2500 bar (250 MPa). The sample interface is based on a thick silicon block with an area of about 14 cm(2). This area is in contact with the sample solution which has a volume of only 6 cm(3). The sample solution is separated from the pressure transmitting medium, water, by a thin flexible polymer membrane. In addition, the HP cell can be temperature-controlled by a water bath in the range 5-75°C. By using an aluminum alloy as window material, the assembled HP cell provides a neutron transmission as high as 41%. The maximum angle of incidence that can be used in reflectivity experiments is 7.5°. The large accessible pressure range and the low required volume of the sample solution make this HP cell highly suitable for studying pressure-induced structural changes of interfacial proteins, supported lipid membranes, and, in general, biomolecular systems that are available in small quantities, only. To illustrate the performance of the HP cell, we present neutron reflectivity data of a protein adsorbate under high pressure and a lipid film which undergoes several phase transitions upon pressurization.     

A System for Viscosity Measurements at Pressures up to 3 GPa and Elevated Temperatures

A falling body viscometer was developed to measure viscosity of lubricants between 10^-1 to 10⁵ Pa.s at high pressures (up to 3 GPa) and temperatures of 20–200°C. The viscometer was incorporated into a variable-support pressure vessel mounted in an O-frame press. A solenoid is used to raise the falling soft iron plunger to its upper position, where it closes a pair of contacts. On deactivating the upper solenoid, the plunger, falls to the lower position to close a second pair of contacts. Fall times are measured by a timer in 0.1s increments. Viscosity of a few fluids, namely a synthetic turbine engine oil, a mineral oil, white gasoline and a 1:1 mixture of the mineral oil and white gasoline were measured to demonstrate capability of the system. For the synthetic turbine engine oil, isoviscous curves for 10², 10³ and 10⁴ Pa.s are presented on a P–T diagram and estimates are made of the viscosity at which dynamic effects can be expected.     

Fabrication and evaluation of a near-infrared hyperspectral imaging system

This paper describes modifications to a hyperspectral imaging microscope that extend its capabilities into the near-infrared (950–1300 nm). The major changes include installing a grating, charge-coupled device camera, and lenses and filters appropriate for infrared wavelengths. Calibration of the system and validation with lead sulfide quantum dots of known emission wavelength is reported. Cells from the breast carcinoma cell line SkBr3 were scanned with lead sulfide quantum dots that emit at 1100 nm as the background and an image which contains the integrated spectral data is presented. We also demonstrate that this instrument is capable of detecting the photoluminescence spectra of single-walled carbon nanotubes dispersed in aqueous solution.     

Construction of phase diagram up to 2 GPa and 200°C for thermo‐reversible gel lubricants by diamond anvil cell

The objective of this research was to make the phase diagram up to 2.0 GPa and 200°C of thermo‐reversible gel lubricants (TR Gel‐Lube) using diamond anvil cell (DAC). TR Gel‐Lube consisted of base fluid and gelling agent. The most important characteristic of TR Gel‐Lube is the reversible change of its physical state. The DAC is able to concerning visual observation of the sol/gel and liquid/viscoelastic–solid transition at high pressure and high temperature. DAC enables the visual observation of the photoelastic effect in order to generate local principal stress difference under the compression field for liquid/viscoelastic‐solid transition of base oil poly‐α‐olefin. The direct observation for sol/gel transition of TR Gel‐Lube at high pressure was also made possible. The phase diagram corresponding to transition from liquid to viscoelastic solid for base oil poly‐α‐olefin and sol to gel for TR Gel‐Lube was made by using DAC. Copyright © 2009 John Wiley & Sons, Ltd.     

Hydrostatic optical cell with simple window structure for low temperature and hydrostatic pressure up to 5 kilobars

A compact gas high-pressure cell with four windows for optical studies of phase transitions at low temperature and hydrostatic pressure up to 5 kilobars has been made. Techniques for sealing window components are discussed.     

Note: Achieving quasi-hydrostatic conditions in large-volume toroidal anvils for neutron scattering to pressures of up to 18 GPa

We present developments that allow neutron-scattering experiments to be performed, with both single-crystal and powder samples, under quasi-hydrostatic conditions to pressures beyond previous limits. Samples of sodium chloride and squaric acid (H(2)C(4)O(4)) have been loaded with argon as the pressure-transmitting medium in encapsulated gaskets redesigned for double-toroidal anvils, using a gas-loading method at ambient temperature. These samples have been compressed up to 18 GPa in a Paris-Edinburgh press, and no evidence of peak broadening in either the single-crystal or the powder experiments was observed.     

High pressure sample cell for total internal reflection fluorescence spectroscopy at pressures up to 2500 bar

Total internal reflection fluorescence (TIRF) spectroscopy is a surface sensitive technique that is widely used to characterize the structure and dynamics of molecules at planar liquid-solid interfaces. In particular, biomolecular systems, such as protein adsorbates and lipid membranes can easily be studied by TIRF spectroscopy. Applying pressure to molecular systems offers access to all kinds of volume changes occurring during assembly of molecules, phase transitions, and chemical reactions. So far, most of these volume changes have been characterized in bulk solution, only. Here, we describe the design and performance of a high pressure sample cell that allows for TIRF spectroscopy under high pressures up to 2500 bar (2.5 × 10(8) Pa), in order to expand the understanding of volume effects from the bulk phase to liquid-solid interfaces. The new sample cell is based on a cylindrical body made of Nimonic 90 alloy and incorporates a pressure transmitting sample cuvette. This cuvette is composed of a fused silica prism and a flexible rubber gasket. It contains the sample solution and ensures a complete separation of the sample from the liquid pressure medium. The sample solution is in contact with the inner wall of the prism forming the interface under study, where fluorescent molecules are immobilized. In this way, the new high pressure TIRF sample cell is very useful for studying any biomolecular layer that can be deposited at a planar water-silica interface. As examples, high pressure TIRF data of adsorbed lysozyme and two phospholipid membranes are presented.     

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.     

Note: Measurement method for sound velocity of melts in large volume press and its application to liquid sodium up to 2.0 GPa

Based on large volume press and conventional pulse-echo ultrasonic technique, we have overcome the difficulty in determining the length of liquid specimen under high pressure, and the sound velocity in liquid Na has been measured up to 2 GPa. The P-V data deduced by our sound velocity results through equation of state is in an excellent agreement with previous data directly determined by piezometer method. This new experimental technique is convenient and ready for use, being expected to advance investigation on thermodynamic properties of liquid metals and other melts under high pressure.     

谐振式MEMS压力传感器的制作及圆片级真空封装

为了提高传感器的品质因数,有效保护谐振器,提出了一种基于绝缘体上硅(SOI)-玻璃阳极键合工艺的谐振式微电子机械系统(MEMS)压力传感器的制作及真空封装方法。该方法采用反应离子深刻蚀技术(DRIE),分别在SOI晶圆的低电阻率器件层和基底层上制作H型谐振梁与压力敏感膜;然后,通过氢氟酸缓冲液腐蚀SOI晶圆的二氧化硅层释放可动结构。最后,利用精密机械加工技术在Pyrex玻璃圆片上制作空腔和电连接通孔,通过硅-玻璃阳极键合实现谐振梁的圆片级真空封装和电连接,成功地将谐振器封装在真空参考腔中。对传感器的性能测试表明:该真空封装方案简单有效,封装气密性良好;传感器在10kPa~110kPa的差分检测灵敏度约为10.66 Hz/hPa,线性相关系数为0.99999 542。     

A high pressure cell for small angle neutron scattering up to 500 MPa in combination with light scattering to investigate liquid samples

We report on a high pressure cell to use with small angle neutron scattering (SANS) in a pressure range up to 500 MPa. The cell offers the new possibility to investigate liquid samples by a specially designed sample chamber, which allows changing of samples relatively easily. Since the cell construction uses sapphire as window material, also light scattering investigations can be performed simultaneously to the SANS measurements. In this article we describe the construction of a high pressure cell and we demonstrate the applicability of the construction for SANS in combination with dynamic light scattering showing data on the biological molecule lysozyme.     

Materials and techniques for pressure calibration by resistance-jump transitions up to 500 kilobars

The resistance jump of alpha-->epsilon transitions for Fe-V alloys up to 20-wt. % V is observed by static compression. It is used along with alpha-->epsilon transitions for Fe-Co alloys and some other transitions as the basis for pressure calibration up to 500 kilobar.     

异径管的热压成形工艺及其质量检测

总结有缝或无缝的同心异径管、偏心异径管和异径弯管的热压成形工艺方法,对38件异径管的外形和壁厚几何 尺寸以及表面硬度进行检测,还对偏心异径管的强度性能进行取样检测。结果分析表明,异径管壁厚均超厚;异径管大 小两个端口的几何尺寸较准确,但壁厚很不均匀,异径弯管壁厚较均匀;超声测厚时,数值偏大,探头分隔面与管件轴线 平行时的实测值与分隔面垂直于管件轴线的实测值相比略大一些,结果危险;异径管两端的表面硬度比中间段的表面硬 度平均低约35%;根据GB1172—74《黑色金属硬度及强度换算值》中的经验公式σb≈3.5378HB(MPa)将布氏硬度换算 为抗拉强度时,结果明显保守。     

A design of backing seat and gasket assembly in diamond anvil cell for accurate single crystal x-ray diffraction to 5 GPa

We designed a new cell assembly of diamond anvil cells for single crystal x-ray diffraction under pressure and demonstrate the application of the cell to the crystallographic studies for ice VI and ethanol high-pressure (HP) phase at 0.95(5) GPa and 1.95(2) GPa, respectively. The features of the assembly are: (1) the platy anvil and unique-shaped backing seat (called as "Wing seat") allowing the extremely wide opening angle up to ±65°, (2) the PFA-bulk metallic glass composite gasket allowing the easy attenuation correction and less background. Thanks to the designed assembly, the R(int) values after attenuation corrections are fairly good (0.0125 and 0.0460 for ice VI and ethanol HP phase, respectively), and the errors of the refined parameters are satisfactory small even for hydrogen positions, those are comparable to the results which obtained at ambient conditions. The result for ice VI is in excellent agreement with the previous study, and that for ethanol HP phase has remarkable contributions to the revision to its structure; the H12 site, which makes gauche molecules with O1, C2, and C3 sites, may not exist so that only trans conformers are present at least at 1.95(2) GPa. The accurate intensities using the cell assembly allow us to extract the electron density for ethanol HP phase by the maximum entropy method.     

Numerical simulation and experimental validation for a novel dielectrophoresis activated cell sorter to achieve high throughput and efficiency

Although previously developed Dielectrophoresis activated cell sorters (DACSes) have achieved high separation efficiency, limitations still exist with respect to the low throughput. In this paper, therefore, a numerical analysis is presented for a novel DACS to achieve not only high efficiency but also high throughput. Additionally, experimental validation is performed based on the results of a numerical simulation. First, streamlines in the channel are investigated according to various flow rate ratios in each outlet. After cells are deflected by a sufficient amount of dielectrophoretic force, they arrive at the tip of the last electrode pair. Their movement is then determined by hydrodynamic force. Therefore, it is important to confirm whether or not the streamline at the tip of the last electrode pair connects to the target area. Based on the streamline analysis results, the particle trajectory under various AC electric fields is investigated using a three-dimensional analysis. Accordingly, an input voltage condition (7 Vp-p at 10 kHz) is selected to confirm the influence of dielectrophoretic force. Conclusively, optimal flow rates under the determined input voltage condition are selected as 10 μl/min and 20 μl/min in outlet A (target area) and outlet B (non-target area), respectively. In order to validate the feasibility of the selected flow rates, a separation test is performed employing a K562 cell–bone marrow cancer cell–as a target cell. In the experiment, the proposed DACS achieves a high throughput of 45000 cells/min as well as a separation efficiency of 96.5% and recovery rate of 47.25%.