气相色谱的电子压力控制技术

在调节气相色谱仪器的诸多性能时，电子压力控制技术能精确控制载气流速，文章叙述了电子压力控制技术在上色谱中应用的基本原理，并以农药样品分析为例介绍了它在进样和柱分离时的作用。     

回流气提法测定水中的氰化物

回流气提法测定水中的氰化物较标准方法（ＧＢ７４８６－８７）有较大的浓缩倍数，可将最低检出浓度降低一个数量级，达０．０００３ｍｇ／Ｌ．     

小型锅炉烟气喷雾分离法脱硫的试验研究

以4t燃煤锅炉为对象，重点研究了喷雾分离法脱硫技术的工艺流程和主要设备，并给出了相应的试验结果。结果表明以清水为吸收剂，液气比≤0．1L／m^3，脱硫效率达到了60％—70％。本装置具有工艺简单、占地省、投资少、运行费用低的优点，特别适合用于中小型锅炉的改造。     

DQ—500型惰气灭火装置

本文提出扑灭瓦斯矿井火灾的惰气灭火装置,并介绍了该装置的工作原理,构造及其应用。研究了风油比与燃气成分的关系;阐述了风油比自控系统对保证燃气成分符合灭火要求的重要意义和作用。本文还对国内外同类灭火装置性能进行比较。通过试验表明,该装置既能扑灭矿井火灾又能抑制瓦斯爆炸,是处理瓦斯矿井火灾理想的灭火新装备。     

The ratio between nitrogen oxides and carbon monoxide total emissions as precursors of tropospheric hydroxyl content evolution

The Main Geophysical Observatory 2D channel photochemical model is used to study the behavior of tropospheric OH within the 30–60°N zonal belt in relation to changing NO_X and CO emissions. The changes of tropospheric OH as a function of the contributions by NO_X and CO emissions during the period 1850–2050 are calculated. Our estimations show that the largest annual increment of total tropospheric OH within the belt considered occurs in the 1985–1995 period, about 0.27% yr⁻¹. Based on scenarios of tropospheric pollution emissions in the first half of 21st century, the total tropospheric OH content will increase more slowly, by 0.12–0.15% yr⁻¹. The maximum growth of OH concentration occurs close to air pollution locations—in the lower troposphere during 1850–1995 but in the upper troposphere in the 21st century when the NO_X source from subsonic aircraft increases faster than the surface source.     

用固相萃取-HPLC法测定水质中杀菌剂多菌灵的方法研究

用固相萃取法萃取水和废水中的多菌灵,取浓缩纯化后的有机相直接进样到高效液相色谱仪,用二极管矩阵检测器检测,根据保留时间外标法定量.     

Validation of geometry modelling approaches for offshore gas dispersion simulations

Computational Fluid Dynamics (CFD) codes are widely used for gas dispersion studies on offshore installations. The majority of these codes use single-block Cartesian grids with the porosity/distributed-resistance (PDR) approach to model small geometric details. Computational cost of this approach is low since small-scale obstacles are not resolved on the computational mesh. However, there are some uncertainties regarding this approach, especially in terms of grid dependency and turbulence generated from complex objects. An alternative approach, which can be implemented in general-purpose CFD codes, is to use body-fitted grids for medium to large-scale objects whilst combining multiple small-scale obstacles in close proximity and using porous media models to represent blockage effects. This approach is validated in this study, by comparing numerical predictions with large-scale gas dispersion experiments carried out in DNV GL's Spadeadam test site. Gas concentrations and gas cloud volumes obtained from simulations are compared with measurements. These simulations are performed using the commercially available ANSYS CFX, which is a general-purpose CFD code. For comparison, further simulations are performed using CFX where small-scale objects are explicitly resolved. The aim of this work is to evaluate the accuracy and efficiency of these different geometry modelling approaches.     

Influence of active mitigation barriers on LNG dispersion

In recent years, particular interest has been direct to the issues of risk associated with the storage, transport and use of Liquefied Natural Gas (LNG) due to the increasing consideration that it is receiving for energy applications. Consequently, a series of experimental and modeling studies to analyze the behavior of LNG have been carried out to collect an archive of evaporation, dispersion and combustion information, and several mathematical models have been developed to represent LNG dispersion in realistic environments and to design mitigation barriers.This work uses Computational Fluid Dynamics codes to model the dispersion of a dense gas in the atmosphere after accidental release. In particular, it will study the dispersion of LNG due to accidental breakages of a pipeline and it will analyze how it is possible to mitigate the dispersing cloud through walls and curtains of water vapor and air, also providing a criterion for the design of such curtains.     

Explosion behavior of n-alkane/nitrous oxide mixtures

The explosion properties of alkane/nitrous oxide mixtures were investigated and were compared with those of the corresponding alkane/oxygen and alkane/air mixtures. The explosion properties were characterized by three parameters: the explosion limit, explosion pressure, and deflagration index. For the same alkane, the order of the lower explosion limits (LELs) of the mixtures was found to be alkane/oxygen ≈ alkane/air > alkane/nitrous oxide. In addition, the mixtures containing nitrous oxide tended to exhibit higher explosion pressures than the corresponding mixtures containing oxygen under fuel-lean conditions. The Burgess–Wheeler law was also observed to hold for the mixtures containing nitrous oxide.