柴油机排气微粒部分流稀释取样系统的研制

设计了一种用于柴油机稳态工况下微粒测量的部分流稀释取样系统,该系统稀释通道内径为１５０ｍｍ全长为２３５０ｍｍ,稀释通道内稀释排气流量为５５６ｍ＾３／ｈ,雷诺数为７３０００,稀释比用ＣＯ２分析仪测量发动机排气和稀释通道内稀释排气的ＣＯ２浓度来计算,试验证明此仪器试验重复性良好。     

Effect of dilution and additive on direct nitridation of ferrosilicon

Ferrosilicon nitrides were fabricated by direct nitridation of ferrosilicon, and the effects of ferrosilicon nitride and α-Si₃N₄ dilution and ammonium chloride (NH₄Cl) additive on characteristics of the nitride products were investigated. The phases of final nitride products consist of α-Si₃N₄, β-Si₃N₄ and iron silicides with various compositions. Long columnar crystals, equiaxed crystals and flower-like crystals were observed in the final products, and fiber or whisker-like crystals with a low degree of crystallization were also found in the nitrides. Both the diluents and additive can improve the nitridation degree, but only the additive can increase the content of α-Si₃N₄ in the nitride products. As a diluent, ferrosilicon nitride can decrease the cost of nitride products, and increase their nitridation degree more than α-Si₃N₄. NH₄Cl made the products fluffy and expansive, while the dimensions of the compact without addition of NH₄Cl remain unchanged during nitridation.     

Simulation of Crude Palm Oil Dilution in a Palm Oil Mill Using Computational Fluid Dynamics

Computational fluid dynamics (CFD) simulation was applied to simulate the dilution of undiluted crude oil (UCO) in a dilution tank of a palm oil mill. Fluid flow and mixing characteristics were examined. Considering the mixing behavior, the mixing of dilution water and UCO occurred as soon as these fluids entered the dilution tank, and the oil mass fraction in the mixture decreased gradually towards the outlet of the tank. Meanwhile, the velocity of dilution water and UCO declined as the fluids moved from their respective inlets. The intensity of turbulence flow remained until near the tank outlet. For the parametric study, the oil mass fraction of diluted crude oil (DCO) increased with higher UCO flow rate and oil mass fraction in the UCO but declined with higher dilution water flow rate.     

Development of a gas micro-flow transfer standard

LNE has ability to calibrate gas micro-flow rates using the dilution method for nitrogen flow rates in the range from 2 µg/s to 200 µg/s or helium ones in the range 0.75–30 µg/s. In addition, a primary constant pressure flowmeter for leak rate measurements from 0.05 µg/s to 35 µg/s is also available. This equipment will be used to validate the dilution method below 30 µg/s. In order to compare these reference facilities, LNE is developing a micro-flow transfer standard (µFTS) in collaboration with ATEQ France, a manufacturer of control equipment for leak testing. The flowmeter consists mainly of an array of three stainless steel capillaries designed to cover the ranges from 0.035 µg/s to 0.35 µg/s, 0.35 µg/s to 3.5 µg/s and 3.5 µg/s to 35 µg/s for nitrogen (0.1–100 ml/h). A dynamic model of the µFTS determines the mass flow rate from the input pressure, the differential pressure of the capillary, the gas temperature, viscosity and density and the length and radius of the capillary. A comparison of both reference methods is carried out with the µFTS from 0.35 µg/s to 35 µg/s.     

顶吹转炉处理低品位废杂铜的生产实践

我公司顶吹转炉处理原料为铜精炼渣和铜品位低于90%的废杂铜混料,投产第一个月存在弃渣含铜品位较高且不稳定的问题,多次出现"泡沫渣"现象,增加了公司铜金属回收成本。对其进行研究分析,在保证正常生产的情况下,改进措施,使弃渣铜品位达到1.0%以下,杜绝"泡沫渣"现象,提高了金属回收率,减少生产成本。     

Comparison of the Composition and Structural Parameters of W/O Microemulsions Containing Gemini Imidazoliums with Those Containing Monomeric Analogues

The composition and structural parameters of W/O microemulsions containing the gemini surfactant 1,4‐bis(3‐alkylimidazolium‐1‐yl) butane bromide [(C_n‐4‐C_n)Br₂, n = 12, 14, 16] + pentan‐1‐ol + octane + water and W/O microemulsions containing the ionic liquid surfactant 1‐alkyl‐3‐methylimidazolium (C_nmimBr, n = 12, 14, 16) + pentan‐1‐ol + octane + water were studied and compared. The mole fractions of the n‐alkyl alcohol at the interfacial layer in (C_n‐4‐C_n)Br₂ based microemulsion systems are always larger than those in C_nmimBr based microemulsion systems. However, the mole fractions of the n‐alkyl alcohol in the oil phase are nearly the same for both the microemulsion systems. The (C_n‐4‐C_n)Br₂ based microemulsion systems have greater absolute values of the free enthalpy values than that for C_nmimBr based systems. In the (C_n‐4‐C_n)Br₂ based microemulsion systems, a large number of cosurfactants at the interfacial layer is conducive to the formation of a smaller droplet W/O microemulsion. The effects of n‐alkyl alcohols, alkanes, salinity and temperature on the composition and structural parameters of the (C_n‐4‐C_n)Br₂ based and C_nmimBr based microemulsion systems were also investigated and discussed.     

Character impact odorants of boiled chicken: changes during refrigerated storage and reheating

 The most potent odorants of freshly boiled chicken and boiled, refrigerated and reheated chicken showing warmed-over flavour (WOF) were screened by dilution experiments. In total, 20 odorants were selected for quantification by stable isotope dilution assays. Calculation of odour activity values (ratio of concentration to odour threshold) indicated methanethiol, (E,E)- and (E,Z)-2,4-decadienal, (E,E)-2,4-nondienal, 2-furfurylthiol, hexanal, octanal and acetaldehyde as the character impact odorants of freshly boiled chicken. Refrigerated storage and reheating of boiled chicken led to a loss of meaty, chicken-like and sweet odour notes and to the formation of green, cardboard-like, metallic off-odours. These changes were mainly caused by a sevenfold increase of hexanal and a sixfold decrease of both (E,E)-2,4-decadienal and 2-furfurylthiol. Sensory experiments confirmed this conclusion. Received: 11 February 1997     

Cu基体表面PTA工艺制备Ni基耐磨层研究

采用等离子粉末堆焊(PTA)工艺在Cu基体表面制备了Ni基耐磨层,对该耐磨层的微观组织、相结构、元素成分、显微硬度性能及高温耐磨性能等进行了研究.结果表明:耐磨层与基体形成良好的冶金结合,稀释率仅为6%,且其显微组织细小,呈枝状晶形貌,硬质相呈弥散分布.耐磨层主要由y相固溶体、Cr23C6、Ni3Fe、和Cr7C3以及...     

Dilution effect of the feed on yield of olefins during catalytic cracking of vacuum gas oil

A vacuum gas oil has been co-fed with nitrogen at different partial pressures in a microacitivity (MAT) unit. The cracking rate versus hydrocarbon partial pressure can be fitted to a first-order kinetic rate equation. On the other hand, hydrogen transfer reactions, which follow second-order kinetics, are more affected than conversion by the decrease in hydrocarbon partial pressure, resulting in an increase in the yield of propylene and in general of LPG olefins. The decrease in conversion, due to the lowering of hydrocarbon partial pressure, could be compensated by a mechanical mixing effect introduced by the dilution gas that improves feed vaporization and mixing.

It will be shown that a MAT unit can be used to show both effects separately, i.e. feed dilution and feed dispersion.     

降解混合型稠油物化性质研究--以辽河盆地西部凹陷为例

利用生物标志物等资料分析降解混合型稠油的地球化学特征及识别标志，研究表明混合型稠油是早期聚集并遭受强烈生物降解的原油与晚期注入的未遭受生物降解的原油的混合物。其地球化学指标具有不协调的特征。原油的组成和性质亦出现与生物降解相反的变化趋势，降解后混合导致稠油“稀化”，从而改善稠油的物理化学性质。各油层降解混合型稠油呈非均衡性，距生油洼陷越近。稠油的稀化越明显。