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大型LNG储罐预冷模型构建和预冷参数计算
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作者 王屹亮 许彦达 +2 位作者 张猛 张进治 胡文佳 《天然气与石油》 2024年第3期55-61,共7页
预冷作业是大型液化天然气(Liquified Natural Gas, LNG)储罐投用前最关键的环节。预冷介质用量、预冷时间以及储罐各部分构件降温速率的控制是大型LNG储罐预冷作业得以顺利进行的重要保证。依托某大型LNG接收站项目,旨在较精确地计算... 预冷作业是大型液化天然气(Liquified Natural Gas, LNG)储罐投用前最关键的环节。预冷介质用量、预冷时间以及储罐各部分构件降温速率的控制是大型LNG储罐预冷作业得以顺利进行的重要保证。依托某大型LNG接收站项目,旨在较精确地计算预冷介质用量。选取最复杂的大型LNG储罐为研究主体,综合考虑保冷材料比热容变化、储罐日常蒸发、预冷介质输送管道漏热等因素,搭建有限元模型进行数值模拟计算,并利用上述结果计算预冷模型中的参数。预冷模型计算结果表明:大型LNG储罐预冷工作实施过程中,提高预冷降温速率可减少预冷介质用量和预冷时间,同时降低大型LNG储罐漏热所消耗的预冷介质占比,但需要注意储罐内元件的温差;考虑输送管线和机械结构漏热,预冷介质用量增多,与现场实际数据更吻合,相对误差不超过5%。研究结果对指导大型LNG储罐预冷操作具有参考价值。 展开更多
关键词 大型LNG储罐 有限元 预冷模型 预冷介质用量
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铁炭复配修复地下水中NO_3^--N的条件研究 被引量:4
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作者 黄国鑫 刘菲 +2 位作者 秦晓鹏 陈鸿汉 金爱芳 《环境工程学报》 CAS CSCD 北大核心 2010年第2期259-263,共5页
采用了铁炭复配修复地下水中NO3--N,探讨了实验条件对修复效果的影响。结果表明,在pH值近中性条件(初始pH 6.42)下,反应时间为1 h时NO3--N修复率达到60.85%;Fe/C=1∶1时介质最佳用量分别为4~5 g;Fe/C=1/1.5时修复率为72.80%;反应速率在... 采用了铁炭复配修复地下水中NO3--N,探讨了实验条件对修复效果的影响。结果表明,在pH值近中性条件(初始pH 6.42)下,反应时间为1 h时NO3--N修复率达到60.85%;Fe/C=1∶1时介质最佳用量分别为4~5 g;Fe/C=1/1.5时修复率为72.80%;反应速率在高振荡强度下大于低振荡强度;氧化铜的催化效果最好,可使修复率提高7.5个百分点。铁炭复配介质修复地下水中NO3--N是有效可行的,修复率随反应时间的增加而提高,在Fe/C=1∶1时修复率与介质用量呈正相关,无限减小Fe/C比并不能无限提高修复率,振荡强度对修复具有显著影响,低振荡强度下的修复过程较高强度存在滞后现象,并非所有金属氧化物催化剂对铁炭修复NO3--N均有促进作用。 展开更多
关键词 铁炭复配 地下水 NO3--N 反应时间 介质用量 Fe/C 振荡强度 催化剂
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Vector Meson Electro-production in Pomeron Exchange Model 被引量:1
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作者 MAWei-Xing LIUBao-Rong +3 位作者 ZHOULi-Juan TANZhen-Qiang HEXiao-Rong GUYun-Ting 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第6期1068-1074,共7页
Based on Pomeron exchange model, elastic production of vector meson in electro-proton interaction is investigated with both linear and non-linear Pomeron trajectory. A numerical calculation for J/psi production is per... Based on Pomeron exchange model, elastic production of vector meson in electro-proton interaction is investigated with both linear and non-linear Pomeron trajectory. A numerical calculation for J/psi production is performed. The effect of the energy scale so and photon virtuality Q(2) on differential cross section are also predicted. A good agreement with experimental data is obtained. Our conclusions are that the Pomeron exchange model is a successful description of J/psi electro-production, the dependence of the differential cross sections on Q2 is negligible, the linear trajectory is a good approximation to non-linearity of the Pomeron trajectory, and the value of the energy scale parameter so is dependent on the momentum transfer, namely its effect is moderate at low momentum transfer but it causes no difference at high momentum transfer vertical bar t vertical bar >= 1.25 GeV2. 展开更多
关键词 vector meson electro-production diffractive process Pomeron exchange model
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Electron-Phonon Interaction in an Annular Quantum Dot
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作者 WU Bo XIE Hong-Jing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第2期493-503,共11页
The confined longitudinal-optical (LO) phonon and surface-optical (SO) phonon modes of a free-standing annular cylindrical quantum dot are derived within the framework of dielectric continuum approximation. It is ... The confined longitudinal-optical (LO) phonon and surface-optical (SO) phonon modes of a free-standing annular cylindrical quantum dot are derived within the framework of dielectric continuum approximation. It is found that there exist two types of SO phonon modes: top SO (TSO) mode and side SO(SSO) mode in a cylindrical quantum annulus. Numerical calculation on CdS annulus system has been performed. Results reveal that the two different solutions of SSO mode distribute mainly at the inner or outer surfaces of the annulus. The dispersion relations and the coupling intensions of phonons in a quantum annulus are compared with those in a cylindrical quantum dot. It is found that the dispersion relations of the two different structures are similar, but the coupling intension of the phonon-electron interaction in quantum annulus is larger than that in quantum dot. The Hamiltonians describing the free phonon modes and their interactions with electrons in the system are also derived. 展开更多
关键词 dielectric continuum approximation phonon modes electron-phonon interaction ANNULAR quantum dots
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