Manometer for Measurement of Differential Pressure of the Order of 2 Millibars

Examining the functioning of sensors for measuring pressure shows that most of them make we of a displacement. The linearity and the sensitivity of this type of sensor are closely dependent on the value of this displacement. For the sake of linearity and repeatabiity of large, signals, the displacement has to be small Consequently the output signals obtained are weak.     

烟气排放污染物(SO2)在线监测系统

紫外 可见差分吸收光谱法 (DOAS)是一种可用于在线式烟气排放污染物自动监测的新型方法 ,它在不改变被测试样成分的前提下 ,可以同时对多种气体进行连续测量。对获得的吸收光谱数据由计算机处理 ,可实时记录烟气中各种污染物的含量 ,并对未知成分的气体进行判断。介绍了基于这种测量方法的测试系统的结构、工作原理 ,并利用所建立的测试系统进行了实验研究。测试结果表明 :采用差分吸收光谱法所测得的SO2 浓度在满量程范围内偏差均≤± 1 5 % ,完全可以满足烟气排放污染物 (SO2 )连续在线监测的要求     

Measurement of the Refractive Indices of H(2)SO(4)-HNO(3)-H(2)O Solutions to Stratospheric Temperatures

Refractive indices of various H(2)SO(4)-H(2)O, HNO(3)-H(2)O, and H(2)SO(4)-HNO(3)-H(2)O solutions were measured at four wavelengths in the visible (351.0, 533.5, 632.9, and 782.6 nm) over a temperature range from 30 to -60 degrees C. The temperature dependence has been determined for the first time to the authors' knowledge. This dependence is of importance for applications to atmospheric aerosols at low temperatures. In particular, it is shown that (1) the molar refractivity of the solutions is independent of temperature, whereas the temperature dependence of the refractive index arises solely through the temperature dependence of the solution's mass density, (2) the molar refractivities of H(2)SO(4) and HNO(3) in a ternary solution may be calculated as the weighted sum of the molar refractivities of two binary solutions evaluated at a concentration that corresponds to the total acid concentration, and (3) the H(2)O molar refractivity in the solutions may be taken equal to that of pure water. Although the data for the ternary system have been used for this model verification, data for binary H(2)SO(4)-H(2)O and HNO(3)-H(2)O solutions were used to improve the accuracy of the modeled refractive indices to better than 0.0017% or 0.15% for concentrations of 5-70 wt.% and wavelengths from the near ultraviolet to the near infrared (0.25-2 mum).     

Dielectric properties of K2Zn2(SO4)3 and (NH4)2 Mg2(SO4)3

Dielectric constant (ɛ), dielectric loss (tan δ) and conductivity (σ) for K₂Zn₂(SO₄)₃ and (NH₄)₂ Mg₂(SO₄)₃ have been measured over the frequency range 100 Hz — 100 kHz and in temperature range 30°C — 400°C. The values of static dielectric constant at room temperature are 7.67 and 4.80 for K₂Zn₂(SO₄)₃ and (NH₄)₂ Mg₂(SO₄)₃ respectively. The plots of log σ against reciprocal temperature at different frequencies of these samples merge into a straight line beyond 250°C and the activation energies calculated in this region are found to be 0.67 eV and 1.98 eV for K₂Zn₂(SO₄)₃ and (NH₄)₂ Mg₂(SO₄)₃ respectively.     

聚偏氟乙烯-氟化二氧化硅有机-无机复合膜的制备及脱硫性能

以聚偏氟乙烯(PVDF)为基膜材料,通过溶胶凝胶-氟化法在PVDF膜表面沉淀氟化的二氧化硅纳米颗粒(fSiO_2),制备聚偏氟乙烯-氟化二氧化硅(PVDF-fSiO_2)有机-无机复合膜。通过衰减全反射傅里叶变换红外光谱、X射线光电子能谱、场发射扫描电子显微镜、接触角测定仪等对PVDF-fSiO_2复合膜进行表征,并评价其脱硫性能。结果表明,PVDFfSiO_2复合膜表面的接触角为106.9°,明显高于PVDF膜的76.4°;由于PVDF-fSiO_2复合膜的良好疏水性能和fSiO_2粒子对基膜的保护作用,随着脱硫时间的延长,PVDF-fSiO_2气-液膜接触器的脱硫率基本保持在79%左右。     

Broadband spectroscopic sensor for real-time monitoring of industrial SO(2) emissions

A spectroscopic system for continuous real-time monitoring of SO(2) concentrations in industrial emissions was developed. The sensor is well suited for field applications due to simple and compact instrumental design, and robust data evaluation based on ultraviolet broadband absorption without the use of any calibration cell. The sensor has a detection limit of 1 ppm, and was employed both for gas-flow simulations with and without suspended particles, and for in situ measurement of SO(2) concentrations in the flue gas emitted from an industrial coal-fired boiler. The price/performance ratio of the instrument is expected to be superior to other comparable real-time monitoring systems.     

Future Performance of Ground-Based and Airborne Water-Vapor Differential Absorption Lidar. II. Simulations of the Precision of a Near-Infrared, High-Power System

Taking into account Poisson, background, amplifier, and speckle noise, we can simulate the precision of water-vapor measurements by using a 10-W average-power differential absorption lidar (DIAL) system. This system is currently under development at Hohenheim University, Germany, and at the American National Center for Atmospheric Research. For operation in the 940-nm region, a large set of measurement situations is described, including configurations that are considered for the first time to the authors' knowledge. They include ultrahigh-resolution measurements in the surface layer (resolutions, 1.5 m and 0.1 s) and vertically pointing measurements (resolutions, 30 m and 1 s) from the ground to 2 km in the atmospheric boundary layer. Even during daytime, the DIAL system will have a measurement range from the ground to the upper troposphere (300 m, 10 min) that can be extended from a mountain site to the lower stratosphere. From the ground, for the first time of which the authors are aware, three-dimensional fields of water vapor in the boundary layer can be investigated within a range of the order of 15 km and with an averaging time of 10 min. From an aircraft, measurements of the atmospheric boundary layer (60 m, 1 s) can be performed from a height of 4 km to the ground. At higher altitudes, up to 18 km, water-vapor profiles can still be obtained from aircraft height level to the ground. When it is being flown either in the free troposphere or in the stratosphere, the system will measure horizontal water-vapor profiles up to 12 km. We are not aware of another remote-sensing technique that provides, simultaneously, such high resolution and accuracy.     

Design and characterization of the balloon-borne Michelson Interferometer for Passive Atmospheric Sounding (MIPAS-B2)

MIPAS-B2 is a balloon-borne limb-emission sounder for atmospheric research. The heart of the instrument is a Fourier spectrometer that covers the mid-infrared spectral range (4-14 microns) and operates at cryogenic temperatures. Essential for this application is the sophisticated line-of-sight stabilization system, which is based on an inertial navigation system and is supplemented with an additional star reference system. The major scientific benefit of the instrument is the simultaneous detection of complete trace gas families in the stratosphere without restrictions concerning the time of day and viewing directions. The specifications, the design considerations, the actual realization of the instrument, and the results of characterization measurements that have been performed are described.     

High-Field Magnetism of the S=5/2 Kagome-Lattice Antiferromagnet KFe3(OH)6(SO4)2 for the Magnetic Field in the Kagome-Plane

We have performed electron spin resonance (ESR) and magnetization measurements on single crystals of K-Fe-jarosite along the a-axis (in the kagome-plane). We have calculated the resonance branches and the magnetization curve using a spin Hamiltonian including the interlayer exchange and the Dzyaloshinsky-Moriya (DM) interactions. By putting the same parameter values for the analyses along the c-axis (normal to the kagome plane), the calculated results show satisfactory agreement with the experimental ones. As a result, we have successfully explained all the experimental results with one set of the intra- and the inter-plane exchange and the DM interaction parameters.     

Low-Temperature Thermal Decomposition of Sulfates to SO(2) for On-Line (34)S/(32)S Analysis

We describe a fast, inexpensive, and safe method of direct SO(2) extraction from BaSO(4) for sulfur isotopic analysis by mass spectrometry. Only two reagents are used: (1) pure NaPO(3), which is mixed with BaSO(4) sample, and (2) Cu foil, from which reaction boats are manufactured. The extraction precedes in the Cu boat placed into a quartz tube connected to a vacuum line. The boat is heated to 650-700 °C while pure SO(2) produced is collected in a "cold finger". Reaction is complete in 7-10 min. We have proven by means of (18)O-enriched BaSO(4) specimens that the oxygen isotopic composition of the SO(2) is totally controlled by (18)O content in NaPO(3), when the weight ratio of the reagent to sample exceeds 6:1. The method described can be used for "on-line" SO(2) preparation for isotopic analysis.     

Separation of H(2)SO(4) + CuSO(4) mixture by diffusion dialysis

Diffusion dialysis of aqueous solution of H(2)SO(4) + CuSO(4) has been investigated in a two-compartment cell with an anion-exchange membrane Neosepta-AFN. The experiments have proved that sulfuric acid permeates well through the membrane used, while cupric sulfate is efficiently rejected. This operation is very effective at high acid concentrations and low concentrations of cupric sulfate. Furthermore, it has been found that even at the highest concentration of CuSO(4), the rejection coefficient is higher than 0.965. The flux of CuSO(4) calculated from the time dependences of the CuSO(4) concentration is negatively influenced by increasing acid concentration.     

Pulsed Laser Photoacoustic Detection of SO(2) Near 225.7 nm

A trace concentration of SO(2) near 225.7 nm has been detected with a master-oscillator power-oscillator laser system for the first time, to our knowledge. A photoacoustic absorption spectrum of SO(2) has been recorded on the (1)A(2)-(1)B(2) (pi-pi*) transition. Parametric dependence of the photoacoustic signal has been investigated. A detection limit (signal-to-noise ratio of 1) of 1.3 parts in 10(9) [1.3 ppbv (parts per billion by volume)] for SO(2) have been determined at 1 atmospheric pressure inside a photoacoustic cell.     

A Tikhonov Regularizing Algorithm for Processing Multiwave Lidar Data in the Absence of Information on the Measurement Error

An algorithm is considered for recovering the aerosol size distribution and also the mean (effective) radius and quantitative concentration from optical data: back-scattering and total attenuation coefficients as measured with a certain error δ at various wavelengths. These quantities are connected by a linear integral Fredholm equation of the first kind. A solution is provided by the modified discrepancy, which enables one to estimate the regularization parameter in the absence of information on the error δ. __________ Translated from Izmeritel'naya Tekhnika, No. 10, pp. 8–14, October, 2005.     

原子吸收分光光度检定结果的测量不确定度评定

本文介绍了原子吸收分光光度检定结果的测量不确定度评定方法。     

高精度零件热变形量测量系统

设计了一种高精度测量零件受热变形量的实验装置.用恒温箱控制温度变化及保持温度稳定,利用电感测头对测量进行定位;同时,利用双频激光干涉仪对电感测头间距离进行精确测量,测头间的距离就是零件的受热变形量.理论分析和实验结果表明,这一系统具有较高的温度控制精度和测量精度.利用该系统对直径为50 mm的圆柱类零件在稳态均匀温度场中相同温度变化下的直径热变形量进行了5次重复性测量,其重复性误差为0.5μm.