固相萃取净化-气相色谱-质谱法测定染料中7种指示性多氯联苯

本文建立了以固相萃取(SPE)前处理净化、结合气相色谱-质谱(GC-MS)测定染料中7种指示性多氯联苯的分析方法。该法将染料样品经溶剂萃取后,通过固相萃取(SPE)净化、浓缩,气相色谱-质谱采用选择离子监测模式(SIM)测定,以保留时间和特征离子定性,外标法定量。     

二氯苯系列产物的气相色谱分析

介绍了在相同条件下分析对二氯苯、邻二氯苯、间二氯苯、1，2，4-三氯苯和氯化苯的气相色谱法。该法采用灵敏度为10^8的1002气相色谱仪或其它类似色谱仪、氢火焰离子化检测器，在选择有机皂土和己二酸乙二醇酯混合固定相(有机皂土：6201担体=5：100；己二酸乙二醇酯：6201担体=5：100)的质量比为(1．6～1．7)：1时，能够有效地分离上述几种组分，从而可以对上述组分进行同时分析。其检出限在10^-6～10^-7之间,线性范围在10^-6～10^-3之间，便于产品检验和环境监测。     

Upscaling hydraulic conductivity: theory and examples from geohydrological studies

This paper presents an overview of the theory of upscaling hydraulic conductivity and describes two case studies in which some of this theory has been applied. The representative hydraulic conductivity of a numerical model block (block conductivity for short) is defined in terms of smaller scale hydraulic conductivities. Also, using elementary examples, some general properties of block conductivities are given. Analytical solutions for the block conductivity are presented that were derived by various authors for uniform flow conditions both in a deterministic and in a stochastic setting. Some results of the hydraulic upscaling theory are illustrated by two case studies from the Netherlands. The first case study deals with deriving the representative hydraulic conductivity tensor of a clay layer. Upscaling results are compared with traditional harmonic averaging. In the second case study the upscaling is used to derive the three-dimensional distribution of block conductivities for a numerical groundwater model of a confining layer of complex deposits. Here stochastic upscaling is used together with a geostatistical simulation approach. The simulated block conductivities are used in a numerical groundwater model and results are compared with pumping tests. When the upscaling is ignored groundwater flow through the deposits is predicted wrongly.     

Effect of additives on formation of natural gas hydrate

The formation of natural gas hydrate (NGH) is studied in this work. Kinetics data of hydrate formation with no agitation were collected at various concentrations of the aqueous solutions with different additives such as alkylpolyglucside, sodium dodecyl benzene sulfonate and potassium oxalate monohydrate. Various kinds of additive increased the formation rates of NGH and its storage capacity and reduced the induction time of NGH formation. Moreover, the storage capacity, the induction time and the hydrate formation rate were influenced by the concentration of the aqueous solution.     

Hydrodynamics and liquid phase axial mixing in orifice pipe reactor

Two phase flow in a horizontal pipe, with orifice plates placed at regular intervals as obstructions, was studied for the effect of phase velocities on flow patterns, fractional phase hold-ups, pressure drop and liquid phase axial dispersion. Radioactive technetium-99m (as an aqueous solution of sodium pertechnatate) was used as tracer. A pulse injection technique with two point measurements was employed. Three different orifice diameters were used (8 mm, 16 mm, and 20 mm) in a pipe diameter of 32 mm. The orifice spacing was 500 mm in all cases. Superficial gas (air) velocity was varied over a range from 0.02 m/s to 1.0 m/s and superficial liquid (water) velocity from 0.03 m/s to 0.85 m/s. Different flow patterns under different flow conditions were identified and a generalised flow map is presented. Variations in hold-ups and pressure drop with flow patterns have been explained. Rational correlations have been developed for fractional phase hold-ups and pressure drop. A preliminary comparison of two phase gas-liquid flow in a horizontal pipe with orifice obstructions (to be called orifice pipe reactor), as a gas-liquid contacting device, is made with a conventional bubble column reactor. Recommendations have been made for future work.     

干熄焦循环气体成分的分析和控制

分析了干熄焦循环气体成分，针对可燃气体成分爆炸的极限值，控制及制定循环气体成分的指标。     

Surface modification of a biomedical poly(ester)urethane by several low‐powered gas plasmas

Several low‐powered gas plasmas were employed to treat a biomedical poly(ester)urethane using the treatment gases of CO₂, O₂, NH₃, and SO₂ with different treatment time (2, 5, 10, and 15 min). The changes of the physical and chemical characteristics of the biopolymer surface were studied. Surface morphology was evaluated by scanning probe microscopy, which showed increased roughness of the surface after plasma treatment. The wettability of the surface was examined by static water contact angle (SCA) measurements, which presented that there was a decrease of SCA in all plasma treatments compared with the untreated surface and that each gas plasma had an optimum treatment time accompanied by a minimum contact angle. X‐ray photoelectron spectroscopy indicated the changes of the surface functional groups. The data demonstrated that CO₂ and O₂ plasmas resulted in the incorporation of oxygen‐containing groups, while NH₃ plasma resulted in the combination of nitrogen‐containing groups, and SO₂ plasma resulted in the formation of sulfur‐containing groups. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1273–1282, 2006     

Trickle Flow Multiplicity: The Influence of the Prewetting Procedure on Flow Hysteresis

The existence of multiple hydrodynamic studies (MHS) in trickle flow is a well-known phenomenon. It is also known that different prewetting procedures result in major differences in MHS when the hydrodynamic variables pressure drop, liquid holdup and gas–liquid mass transfer are considered. Given a certain prewetting procedure one still has the option to perform flow hysteresis cycles to achieve an even wider variety of MHS. Although numerous studies have been performed on trickle flow hysteresis, none have attempted to decouple the hysteresis behaviour from the prewetting procedure followed. Accordingly there are numerous hysteresis possibilities that have not been investigated. In this work a single liquid and gas cycle were performed for four distinct prewetting procedures described here as a dry bed, a Levec type prewetted bed, Kan prewetted bed (achieved by increasing either the liquid or the gas flow rate until the pulsing flow regime is reached) and a Super prewetted bed. Pressure drop, liquid holdup and gas–liquid mass transfer are the hydrodynamic parameters studied to quantify the various MHS. It is shown that the shape and extent of the hysteresis cycle are strongly dependant on the prewetting procedure. In terms of flow structure, similar hysteresis trends on the Kan Liquid and Super prewetting modes indicate that these modes are hydrodynamically similar. The additional measurement of the hysteresis behaviour of gas–liquid mass transfer proofs that neither holdup nor pressure drop can be used as an indicator of the distribution uniformity.     

制定合理的价格政策促进天然气化工的发展--西气东输工程的天然气利用问题

分析了天然气化工用户对低气价承受能力的原因,指出要真正实现天然气在化工领域的应用首先要靠国家政策鼓励,其次要靠本身取得更多的技术突破.提出了对我国天然气定价机制的改革意见,呼吁我国各方面的技术力量要优先重视3种新工艺的开发研究,即天然气制合成气、天然气制乙烯和天然气制液体燃料及芳烃.     

气相色谱法测定饲料香味剂中香味成分的含量

用气相色谱氢火焰离子化检测器，SE－52毛细管柱对四甲苯做内标，分别饲料香味剂中NB－68200香精液组分的含量，分离效果好。