加热状态选择对近沸体系丙烯/丙烷分离能耗影响的探讨

以近沸体系丙烯/丙烷分离为例介绍了化工模拟软件Aspen Plus在化工原理精馏单元的应用,研究了加热状态选择对能耗和年总费用的影响.为了提高学生工程实践能力,探讨了泡点、露点、过冷、过热、气液混合(气化率0.5)等5种进料状态分离丙烯/丙烷对能耗和经济费用的影响,在塔板数、进料板进料温度与压力、塔顶丙烯出料纯度不变条件下,过冷进料的常规工艺流程和泡点塔顶蒸气再压缩热泵工艺流程能耗和年度总费用(TAC)最小.相比常规工艺流程,塔顶蒸气再压缩热泵精馏工艺流程泡点进料可节能65％,年费用节约56％.     

磁场对瓦斯爆炸及其传播的影响

为了弄清煤矿井下巷道中变电站、大型机电设备等产生较强的磁场对瓦斯爆炸的影响机理和影响程度,实验研究了外加磁场对瓦斯爆炸过程中爆炸应力波和火焰传播速度的影响,并从磁场影响瓦斯爆炸及其传播的传质、传热、反应过程等进行了理论分析.研究结果表明:外加磁场能增加瓦斯爆炸强度和火焰传播速度以及增大压力波超压峰值和火焰传播速度峰值,...     

磁性石墨烯@聚多巴胺纳米复合材料分离去除水中双酚A

本文通过水热法和多巴胺的自我团聚反应合成了磁性石墨烯@聚多巴胺(PDA@MG)纳米复合材料,该材料具有表面积大,含有丰富的π电子共轭体系、很好的水溶液分散性,易分离及可重复使用等特点。以PDA@MG为吸附剂材料,研究了其对水溶液中双酚A(BPA)的吸附性能。考察了吸附时间、温度、溶液的pH、吸附剂的用量等因素对该材料吸附性能的影响。结果表明在优化实验条件下,PDA@MG对BPA的最大吸附容量为151.3mg/g。PDA@MG具有优异的循环吸附性能,经过10次循环使用后其吸附能力没有明显减弱。     

Design of all-optical temporal differentiator using a Moir fiber grating

We design and demonstrate an all-optical temporal differentiator based on a simple Moir fiber grating operated in reflection. The simulation results prove that a single Moir fiber grating with only one π-phase shifted point can act as the first-order temporal differentiator and that a Moir fiber grating incorporating two symmetrical π-phase shifted points can act as the second-order temporal differentiator. A practical Moir fiber grating is fabricated, thereby proving that such a grating can act as the first-order temporal differentiator. Our results verify the feasibility, flexibility, and accuracy of the proposed method.     

基于Er∶YAG单频可调谐激光器的甲烷吸收光谱测量

采用1.6μm激光差分吸收是探测甲烷(CH4)气体浓度的一种重要手段。通过对CH4气体吸收光谱的理论分析及计算,并基于Er∶YAG单频可调谐激光器,在实验室测量了CH4气体对1.645μm激光的吸收谱线。实验结果对研制用于测量CH4气体浓度的差分吸收激光雷达光源有重要意义。     

次贷危机中国际大宗商品期货中的国际热钱走向

基于波动率调整后的回归模型,对比研究次贷危机爆发前的非危机阶段以及危机爆发后的危机Ⅰ、Ⅱ三个阶段,代表套期保值的商业交易商以及代表国际热钱等投机资本的非商业交易商在农产品、牲畜、能源、金属、软商品、金融期货6类国际大宗商品期货间的流动方向。研究发现:相比危机前的套期保值资金投资规模减少,国际热钱投机规模增加,比危机前更热衷于参与国际大宗商品期货市场投资;在危机中,代表套期保值者的商业交易商投资原油期货的同时,也增加了对收益率更稳定的黄金、十年期国债期货的交易.而代表国际热钱等投机者的非商业交易商并没有转向持有收益率更稳定的黄金、十年期国债等金融期货,反而投机于能源期货市场以及代表生物能源的农产品、软商品期货市场.在欧洲主权债务恶化的危机Ⅱ期比危机I期,套期保值者的投资行为变化不大,而投机者的投机行为变化较大,资金流向流动性高,收益快的三个月欧洲美元期货.     

Local hydrated structure of an Fe2+/Fe3+ aqueous solution: an investigation using a combination of molecular dynamics and X-ray absorption fine structure methods

The hydrated shell of both Fe2+ and Fe3+ aqueous solutions are investigated by using the molecular dynamics (MD) and X-ray absorption structure (XAS) methods. The MD simulations show that the first hydrated shells of both Fe2+ and Fe3+ are characterized by a regular octahedron with an Fe-O distance of 2.08 for Fe2+ and 1.96 for Fe3+, and rule out the occurrence of a Jahn-Teller distortion in the hydrated shell of an Fe2+ aqueous solution. The corresponding X-ray absorption near edge fine structure (XANES) calculation successfully reproduces all features in the XANES spectra in Fe2+ and Fe3+ aqueous solution. A feature that is located at energy 1 eV higher than the white line (WL) in an Fe3+ aqueous solution may be assigned to the contribution of the charge transfer.     

Analysis of dispersion compensation for position-dependence in externally modulated CATV lightwave systems by using chirped fiber grating

Transmission of amplitude-modulated sub-carrier multi-plexed (AM-SCM) analog optical signals in single modefiber is an important and useful technology. Amplitude-modulation vestigial-sideband (AM-VSB) cable televi-sion (CATV) systems have been widely used all over theworld. Apart from 1310-nm optical CATV technology,1550-nm systems have been used for longer transmis-sion distance and more multiplexed channel numbers[1,2].However, it is found that fiber dispersion, combined withthe self-…     

液体表面低频声波的非线性声光效应

实现了液体表面上低频声波的光衍射,得到了稳定的、具有高阶衍射的高反衬衍射图样.理论上首次考虑到表面声波中的高次谐波,得到了相应的非线性条件下衍射强度分布的解析表达式,并将这种非线性理论与实验结果进行对比.对比结果表明,非线性理论与实验结果有更高的吻合程度.