纳米制冷剂在水平光管内沸腾换热的实验研究

纳米制冷剂能否强化管内沸腾换热,目前尚无明确的结论.将配制0.1 g/L的CNTs/R141b纳米制冷剂在内径为8.12 mm的水平光滑圆管内进行沸腾换热实验,光管采用电加热丝进行恒热流密度加热.纳米制冷剂采用HCFC141b混加碳纳米管,体积密度为0.1 g/L.实验测试范围为：（i）质量流速为95.7-382.9 kg/（m2.s）;（ii）热流密度为5-20 kW/m2;（iii）入口干度为0.1-0.8.考察了质量流速、干度及热流密度等因素对纳米制冷剂管内沸腾换热的影响.实验结果表明：在低质量流速（95.7 kg/（m2.s））下纳米制冷剂能够强化管内沸腾换热,随着流量及平均干度增加,纳米制冷剂强化换热的效果将会变小,甚至引起换热恶化.     

HEHEHP-煤油溶液淋洗的阴离子交换色层法分离稀土元素的研究

引言 用与水不相混溶的有机萃取剂作淋洗剂的离子交换色层法提出于1975年。1979年杨伯和等人用三脂肪胺硫酸盐的煤油溶液从吸附有铀的阴离子交换树脂上洗脱出高纯度的铀。1980年何寿椿等人用四苯硼钠的甲基异丁基酮等的溶液作淋洗剂在阳离子交换树脂柱上实现了Rb和Cs的分离。与此同时,江林根等人用HDEHP的煤油溶液作淋洗剂,在阳离     

Decolourization of dye-containing effluent using mineral coagulants produced by electrocoagulation

The colour and colour causing-compounds has always been undesirable in water for any use, be it industrial or domestic wastewaters. The discharge of such effluents causes excessive oxygen demand in the receiving water and then a treatment is required before discharge into ecosystems. This study examined the possibility to remove colour causing-compounds from effluent by chemical coagulation, in comparison with direct electrocoagulation. The inorganic coagulants (C₁, C₂ and C₃) in the form of dry powder tested, were respectively produced from electrolysis of S₁ = [NaOH (7.5 × 10⁻³ M)], S₂ = [NaCl (10⁻² M)], and S₃ = [NaOH (7.5 × 10⁻³ M) + NaCl (10⁻² M)] solutions, using sacrificial aluminium electrodes operated at an electrical potential of 12 V. Reactive textile dye (CI Reactive Red 141) was used as model of colour-causing compound prepared at a concentration of 50 mg l⁻¹. The best performances of dye removal were obtained with C₂ having a chemical structure comprised of a mixture of polymeric specie (Al₄₅O₄₅(OH)₄₅Cl) and monomeric species (AlCl(OH)₂·2H₂O and Al(OH)₃). The removal efficiency (R_A) evaluated by measuring the yields of 540 nm-absorbance removal varied from 41 to 96% through 60 min of treatment by imposing a concentration of C₂ ranging from 100 to 400 mg l⁻¹. The effectiveness of the treatment increased and the effluent became more and more transparent while increasing C₂ concentration. The comparison of chemical treatment using C₂ coagulant and direct electrocoagulation of CI Reactive Red 141 containing synthetic solution demonstrated the advantage of chemical treatment during the first few minutes of treatment. A yield of 88% of absorbance removal was recorded using C₂ coagulant (400 mg l⁻¹) over the first 10 min of treatment, compared to 60% measured using direct electrocoagulation while imposing either 10 or 15 V of electrical potential close to the value (12 V) required during C₂ production. However, at the end of the treatment (after 60 min of treatment), CI Reactive Red 141 pollutant was completely removed from solution (540 nm-absorbance removal of 100%) using direct electrochemical treatment, compared to 96.4% of absorbance removed while treating dye-containing synthetic solution by means of C₂ coagulant.     

新一代硬质聚氨酯泡沫塑料发泡剂的应用

对目前几种CFC-11替代技术的优缺点和发展现状做了简单分析，介绍现有最成熟的新一代聚氨酯泡沫塑料发泡剂——HCFC-141b(1，1-二氯-1-氟乙烷)的一些基本性能，并讨论了HCFC-141b替代CFC-11后可能会引起的一些问题以及需采取的措施。     

第三代短波通信网

美国军用短波网络标准MIL-STD-181-141B中的附录C定义了第三代短波通信网中的关键技术—自动链路建立(ALE)。就此技术进行了比较全面介绍,并且用同步个人呼叫的实例来说明。     

The thermal conductivity of CFC alternatives HFC-125 and HCFC-141b in the liquid phase

The liquid thermal conductivities of the CFC alternatives, HFC-125, and HCFC-141b measured by a transient hot-wire apparatus with one bare platinum wire are reported in the temperature ranges from 193 to 333 K (HFC-125, CHF₂, CF₃) and from 193 to 393 K (HCFC-141b,CCI₂F-CF₃), in the pressure ranges from 2 to 30 MPa (HFC-125) and from 0.1 to 30 MPa (HCFC-141b), respectively. The results have been estimated to have an accurancy of ±0.5%. The liquid thermal conductives obtained have been correlated by a polynomial of temperature and pressure which can represent the experimental results within the standard deviations of 0.49% for HFC-125 and 0.46% for HCFC-141b, respectively.     

Thermal conductivity of halogenated ethanes,HFC-134a,HCFC-123, and HCFC-141b

The gaseous thermal conductivity of three CFC alternatives, HFC-134a (1,1,1,2-tetrafluoroethane), HCFC-123 (1,1-dichloro-2,2,2-trifluoroethane), and HCFC-141b (1,1-dichloro-1-fluoroethane), has been measured in the temperature ranges 273–363 K (HFC-134a) and 313–373 K (HCFC-123, HCFC-141b) at pressures up to saturation. The measurements were performed with a new improved transient hot-wire apparatus. The uncertainty of the experimental data is estimated to be within 1%. The gaseous thermal conductivity obtained in this work together with the liquid thermal-conductivity data from the literature were correlated with temperature and density by an empirical equation based on the excess thermal-conductivity concept. The equation is found to represent the experimental results with average deviations of 2.5 % for HFC-134a, 0.75% for HCFC-123, and 0.55% for HCFC-141b, respectively.     

1000MW级火电机组旁路系统作用及配置

介绍当前世界上美、日、欧等不同技术体系的大机组旁路系统的配置特点，对旁路系统的诸多作用及应用时须注意的问题作了阐述。大容量旁路系统不仅能缩短启动时间，且能使锅炉直接进入纯直流状态运行，有利于热态启动机炉蒸汽参数的配合。锅炉带大容量旁路启动，能确保汽轮机启动的蒸汽品质，大大减轻汽轮机固体颗粒侵蚀，甚至替代冲管等。全容量高压旁路能取代过热器安全门，并能进行滑压运行跟踪溢流，提高汽轮机的安全性；再配置全容量或大容量低压旁路，辅以控制系统的配合，能实现停电不停机、停机不停炉及机组快速甩负荷（FCB）等。因此，1000MW级超超临界机组旁路配置以100％高旁＋（50％-70％）低旁最为合理，高、低旁路最低配置不宜小于40％。     

600MW超超临界机组参数选择的技术经济分析

综述国外超超临界机组的技术路线,介绍国内超超临界机组的技术开发情况,对600MW超超临界机组参数的选择进行技术经济分析。