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991.
K.C. Mills 《北京科技大学学报(英文版)》2009,16(3):261-264
Crystallization properties play an important role in keeping a smooth running of continuous casting process and high sur-face quality of cast strands. To reduce fluorine pollution in slag, a new type of CaO-SiO2-Na2O (CSN) based mold flux was studied. The solidification and crystallization properties, including crystallization temperature, crystallization ratio and solidification minera-graphy, were measured, which were compared with the CaO-SiO2-CaF2 (GF) mold flux. The results show that the crystallization performance is equal to the high fluoride mold powder and CSN can be used for peritectic steel grades sensitive to longitudinal cracking in continuous casting. 相似文献
992.
Hong Zhang) Xiao-gang Li) Cui-wei Du) Hui-bin Qi) ) School of Materials Science Engineering University of Science Technology Beijing Beijing China ) Institute of Welding Surface Technology Baoshan Iron & Steel Co. Ltd. Shanghai China 《北京科技大学学报(英文版)》2009,16(4):414-421
The corrosion behavior and mechanism of hot-dip galvanized steel and interstitial-free (IF) substrate with alkaline mud adhesion were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), and linear polarization. The results show that non-uniform corrosion occurs on the galvanized steel and IF substrate during 250 h with the mud adhesion. The corrosion products on the galvanized steel are very loose and porous, which are mainly ZnO, Zn5(OH... 相似文献
993.
Di-feng Wu) Shu-sen Cheng) Zi-jian Cheng) ) School of Metallurgical Ecological Engineering University of Science Technology Beijing Beijing China ) Steelmaking Plant Jiuquan Iron Steel Co. Ltd. Jiayuguan China 《北京科技大学学报(英文版)》2009,16(1):25-31
The key to reduce shell breakout in the continuous casting process is to control shell thickness in the mold.A numerical simulation on the turbulent flow and heat transfer coupled with solidification in the slab mold using the volume of fluid (VOF) model and the enthalpy-porosity scheme was conducted and the emphasis was put upon the flow effect on the shell thickness profiles in longitudinal and transverse directions.The results show that the jet acts a stronger impingement on the shell of narrow face,which causes a zero-increase of shell thickness in a certain range near the impingement point.The thinnest shell on the slab cross-section locates primarily in the center of the narrow face,and secondly near the comer of the wide face.Nozzle optimization can obviously increase the shell thickness and make it more uniform. 相似文献
994.
995.
橡胶是热的不良导体,因此较厚的橡胶模制品往往需要较长的硫化周期。据Hills报道,橡胶模压制品的硫化时间近似地与其厚度的平方成正比。对于较薄的模制品,橡胶在模腔内硫化时的温度能很迅速地达到外界所施加的值(例如模具内表面的温度)并在整个硫化周期内保持稳定,因而这种模制品的硫化比较均匀。对于较厚的模制品,情况就有所不同了,即: 相似文献
996.
在美国、欧洲和世界上其他许多地方,一股从昆虫综合治理计划中减少化学杀虫剂使用的压力正在不断地增强。其主要原因是:害虫产生抗性,天敌消失和自然生态系统的破坏。公众担心由于化学杀虫剂的不断使用,残留的有害物质会进一步污染环境,尤其是对食品和水源。尽管这些忧虑常常并不正确,但是毫无疑问,这些公众意见促成了一系列限制农药应 相似文献
997.
引言烯烃生产的现代裂解反应器的最佳设计,要求各种反应动力学的精确计算机模型。不像轻烃那样,其裂解动力学已得到较好的了解;而复杂烃类原料(如石脑油、柴油)裂解的模拟进展,则受到限制。在开发用于这类原料的可靠裂解模型时,其中心的课题是确定原料的转化率或裂解深度问题。由于原料组分数多,且由于使用常规的检测方法不能测定原料中的大多数成分,因而原料转化率的直接确定无法考虑。在反应器出口物料中原料组分的定量分析也遇到同样困 相似文献
998.
999.
Gries R Khaskin G Clearwater J Hasman D Schaefer PW Khaskin E Miroshnychenko O Hosking G Gries G 《Journal of chemical ecology》2005,31(3):603-620
(Z, Z)-6,9-Heneicosadien-11-one (Z6Z9-11-one-21Hy) was identified as the major sex pheromone component of the painted apple moth (PAM), Teia anartoides (Lepidoptera: Lymantriidae), on the basis of (1) comparative gas chromatographic-electroantennographic detection (GC-EAD) analyses, GC-mass spectrometry (MS), high-performance liquid chromatography (HPLC)-MS, and HPLC-UV/visible spectroscopy of pheromone gland extracts and authentic standards; (2) GC-EAD analyses of effluvia of calling females; and (3) wind tunnel and field trapping experiments with a synthetic standard. In field experiments in Australia, synthetic Z6Z9-11-one-21Hy as a single component attracted male moths. Wind tunnel experiments suggested that a 4-component blend consisting of Z6Z9-11-one-21Hy, (6Z,9R,10S)-cis-9,10-epoxy-heneicosene (Z6-9R10S-epo-21Hy), (E, E)-7,9-heneicosadien-6,11-dione (E7E9-6,11-dione-21Hy), and 6-hydroxy-(E, E)-7,9-heneicosadien-11-one (E7E9-6-ol-11-one-21Hy) (all present in pheromone gland extracts) might induce more males to orient toward, approach, and contact the source than did Z6Z9-11-one-21Hy as a single component. Additional experiments are needed to determine conclusively whether or not Z6-9R10S-epo-21Hy, E7E9-6,11-dione-21Hy, and E7E9-6-ol-11-one-21Hy might be minor sex pheromone components of PAM. Moreover, attractiveness of synthetic pheromone and virgin PAM females needs to be compared to determine whether synthetic pheromone could replace PAM females as trap baits in the program to monitor eradication of exotic PAM in New Zealand. 相似文献
1000.
Cabrera A Eiras AE Gries G Gries R Urdaneta N Mirás B Badji C Jaffe K 《Journal of chemical ecology》2001,27(10):2097-2107
Five candidate pheromone components were identified by analyzing pheromone gland extracts by gas chromatography (GC), coupled GC-electroantennographic detection (EAD), and coupled GC-mass spectrometry (MS): (E)-11-hexadecenol(E11–16 : OH), (Z)-11-hexadecenol (Z11–16 : OH),(E)-11-hexadecenal, (E)-11-hexadecenyl acetate, and (Z)-3,(Z)-6,(Z)-9-tricosatriene (Z3,Z6,Z9–23 : Hy). In electroantennogram (EAG) recordings, synthetic E11–16 : OH elicited stronger antennal responses at low doses than other candidate pheromone components. Field tests demonstrated that synthetic E11–16 : OH as a trap bait was effective in attracting males, whereas addition of Z11–16 : OH inhibited the males' response. Z3,Z6,Z9–23 : Hy strongly enhanced attractiveness of E11–16 : OH, but was not attractive by itself. A pheromone blend with synergistic behavioral activity of an alcohol (E11–16 : OH) and hydrocarbon (Z3,Z6,Z9–23 : Hy) component is most unusual in the Lepidoptera. The synthetic two-component pheromone is approximately 60 times more attractive than the female-produced blend and might facilitate the control of this pest. 相似文献