In remote regions with availability of wind energy, a RDG （renewable distributed generation） system is an advantageous alternative to increase the provision of electrical supply. Usually, these systems are structure...In remote regions with availability of wind energy, a RDG （renewable distributed generation） system is an advantageous alternative to increase the provision of electrical supply. Usually, these systems are structured on the basis of a connection to an existing weak grid. When the grid is out of service, the system may operate in islanding mode, if the RDG configuration allows it, continuing the provision of energy with standard voltage and frequency values. Facing the latter situation, a wind-diesel/gas generation system is proposed, with a conversion and control strategies based on a variable speed wind turbine employing a DFIG （doubly fed induction generator）, a SC （ultracapacitor） storage system and a SG （synchronous generator） driven by a diesel/gas engine.展开更多
采用优化的RDG (Rappaz-Drezet-Gremaud)热裂模型预测了Mg-5Zn-x Er (x=0.83、1.25、2.5、5,质量分数,%)三元多相合金的铸造热裂敏感性,并利用"约束杆"钢模铸造(CRC)实验评价了该合金的热裂敏感性。结果表明,优化的RDG热裂模...采用优化的RDG (Rappaz-Drezet-Gremaud)热裂模型预测了Mg-5Zn-x Er (x=0.83、1.25、2.5、5,质量分数,%)三元多相合金的铸造热裂敏感性,并利用"约束杆"钢模铸造(CRC)实验评价了该合金的热裂敏感性。结果表明,优化的RDG热裂模型可准确地预测Mg-5Zn-x Er镁合金的热裂敏感性:随着Er含量的增加,合金的热裂敏感性呈先增加后降低的趋势,当Er含量为2.5%时合金的热裂敏感性最高,当Er含量为5.0%时合金的热裂敏感性最低,与实验结果相一致。对铸件凝固曲线、相组成、微观组织等进一步分析表明,当Er含量提高至2.5%时,合金凝固过程发生包晶反应生成I相的同时消耗了液相,并且扩大了合金的凝固温度区间,使合金的热裂敏感性上升;Er含量继续提高至5.0%时,合金在凝固过程中发生L→α-Mg+W的共晶反应,凝固温度区间减小,有利于凝固后期枝晶间裂纹的补缩,显著降低了合金的热裂敏感性。展开更多
The hot cracking tendency of 7075 semi-solid alloy under different conditions was studied by critical diameter method.The experiment and simulation results show that the dendrite arms of the rod grow from the edge to ...The hot cracking tendency of 7075 semi-solid alloy under different conditions was studied by critical diameter method.The experiment and simulation results show that the dendrite arms of the rod grow from the edge to the center.The smaller the diameter of the rod is,the more obvious the directional growth of dendrite is,and the greater the tendency of hot cracking is.Compared with ordinary melt,for semi-solid slurry,increasing mould temperature or decreasing pouring temperature can significantly decrease hot cracking tendency of 7075 alloy,decreasing hot cracking grade from 256 to 100 mm^2.Furthermore,based on the RDG criterion,the effects of solidification conditions on the hot cracking tendency were discussed combined with simulation.At the same time,the application and development of RDG criterion were also researched.展开更多
Anion can be identified by pyromellitic imide-azacyclophane which is one of the host compounds.This article investigated the interaction between the host and organic pollution compounds.The host and other eight compou...Anion can be identified by pyromellitic imide-azacyclophane which is one of the host compounds.This article investigated the interaction between the host and organic pollution compounds.The host and other eight compounds were optimized by DFT（density functional theory） B3LYP/6-31G level and the energy of compounds was corrected using Boys-Bemardi method.On the basis of B3LYP/6-31G optimized geometries,the RDG function and sign（λ2（r））ρ（r） function values of space points were calculated,and color RDG isosurface map was drawn.3He chemical shift was calculated by the B3LYP/6-31G method.The results showed that the eight organic pollution molecules with the host one shaped stable configurations by hydrogen bonds,respectively.The stabilization energy of complexes 4 and 7 showed repulsion（steric effects） of cyclophane cage observably affecting the stability of the complexes.The location,intensity and the type of interaction in complex 1 were analyzed through color-filled RDG isosurface map.Aromaticity calculations showed that the weak interaction reduced the transverse induction ring current in the host rings,and deteriorated the aromaticity of compounds.展开更多
为了研究氮铂混合改性石墨烯对燃煤电厂产生汞污染物的吸附作用,基于量子化学理论构建了氮铂混合改性石墨烯模型,利用密度泛函理论模拟了烟气中汞污染物在氮铂混合改性石墨烯表面的吸附。计算得到了Hg^0、HgCl2和HgBr2在氮铂混合改性石...为了研究氮铂混合改性石墨烯对燃煤电厂产生汞污染物的吸附作用,基于量子化学理论构建了氮铂混合改性石墨烯模型,利用密度泛函理论模拟了烟气中汞污染物在氮铂混合改性石墨烯表面的吸附。计算得到了Hg^0、HgCl2和HgBr2在氮铂混合改性石墨烯表面的吸附构型和吸附能,并利用分子中的原子理论(Atoms in Molecule)和约化密度梯度(Reduced Density Gradient)方法研究了吸附体系的成键类型。结果表明:随着掺杂氮原子数目的增多,氮铂混合改性石墨烯吸附Hg^0、HgCl2和HgBr2能力得到提升。当掺杂3个氮原子时,氮铂混合改性石墨烯吸附单质汞吸附能为98.62 kJ/mol,其吸附能相比传统的碳基吸附剂有明显提升;此时Hg^0、HgCl2和HgBr2被吸附稳定后的产物中,汞原子和铂原子之间的作用力更加稳定。展开更多
文摘In remote regions with availability of wind energy, a RDG （renewable distributed generation） system is an advantageous alternative to increase the provision of electrical supply. Usually, these systems are structured on the basis of a connection to an existing weak grid. When the grid is out of service, the system may operate in islanding mode, if the RDG configuration allows it, continuing the provision of energy with standard voltage and frequency values. Facing the latter situation, a wind-diesel/gas generation system is proposed, with a conversion and control strategies based on a variable speed wind turbine employing a DFIG （doubly fed induction generator）, a SC （ultracapacitor） storage system and a SG （synchronous generator） driven by a diesel/gas engine.
文摘采用优化的RDG (Rappaz-Drezet-Gremaud)热裂模型预测了Mg-5Zn-x Er (x=0.83、1.25、2.5、5,质量分数,%)三元多相合金的铸造热裂敏感性,并利用"约束杆"钢模铸造(CRC)实验评价了该合金的热裂敏感性。结果表明,优化的RDG热裂模型可准确地预测Mg-5Zn-x Er镁合金的热裂敏感性:随着Er含量的增加,合金的热裂敏感性呈先增加后降低的趋势,当Er含量为2.5%时合金的热裂敏感性最高,当Er含量为5.0%时合金的热裂敏感性最低,与实验结果相一致。对铸件凝固曲线、相组成、微观组织等进一步分析表明,当Er含量提高至2.5%时,合金凝固过程发生包晶反应生成I相的同时消耗了液相,并且扩大了合金的凝固温度区间,使合金的热裂敏感性上升;Er含量继续提高至5.0%时,合金在凝固过程中发生L→α-Mg+W的共晶反应,凝固温度区间减小,有利于凝固后期枝晶间裂纹的补缩,显著降低了合金的热裂敏感性。
基金Project(17YF1407100)supported by the Shanghai Sailing Program of ChinaProject(17PJ1408600)supported by Shanghai Pujiang Program of China
文摘The hot cracking tendency of 7075 semi-solid alloy under different conditions was studied by critical diameter method.The experiment and simulation results show that the dendrite arms of the rod grow from the edge to the center.The smaller the diameter of the rod is,the more obvious the directional growth of dendrite is,and the greater the tendency of hot cracking is.Compared with ordinary melt,for semi-solid slurry,increasing mould temperature or decreasing pouring temperature can significantly decrease hot cracking tendency of 7075 alloy,decreasing hot cracking grade from 256 to 100 mm^2.Furthermore,based on the RDG criterion,the effects of solidification conditions on the hot cracking tendency were discussed combined with simulation.At the same time,the application and development of RDG criterion were also researched.
文摘Anion can be identified by pyromellitic imide-azacyclophane which is one of the host compounds.This article investigated the interaction between the host and organic pollution compounds.The host and other eight compounds were optimized by DFT（density functional theory） B3LYP/6-31G level and the energy of compounds was corrected using Boys-Bemardi method.On the basis of B3LYP/6-31G optimized geometries,the RDG function and sign（λ2（r））ρ（r） function values of space points were calculated,and color RDG isosurface map was drawn.3He chemical shift was calculated by the B3LYP/6-31G method.The results showed that the eight organic pollution molecules with the host one shaped stable configurations by hydrogen bonds,respectively.The stabilization energy of complexes 4 and 7 showed repulsion（steric effects） of cyclophane cage observably affecting the stability of the complexes.The location,intensity and the type of interaction in complex 1 were analyzed through color-filled RDG isosurface map.Aromaticity calculations showed that the weak interaction reduced the transverse induction ring current in the host rings,and deteriorated the aromaticity of compounds.
文摘为了研究氮铂混合改性石墨烯对燃煤电厂产生汞污染物的吸附作用,基于量子化学理论构建了氮铂混合改性石墨烯模型,利用密度泛函理论模拟了烟气中汞污染物在氮铂混合改性石墨烯表面的吸附。计算得到了Hg^0、HgCl2和HgBr2在氮铂混合改性石墨烯表面的吸附构型和吸附能,并利用分子中的原子理论(Atoms in Molecule)和约化密度梯度(Reduced Density Gradient)方法研究了吸附体系的成键类型。结果表明:随着掺杂氮原子数目的增多,氮铂混合改性石墨烯吸附Hg^0、HgCl2和HgBr2能力得到提升。当掺杂3个氮原子时,氮铂混合改性石墨烯吸附单质汞吸附能为98.62 kJ/mol,其吸附能相比传统的碳基吸附剂有明显提升;此时Hg^0、HgCl2和HgBr2被吸附稳定后的产物中,汞原子和铂原子之间的作用力更加稳定。
