Developing effective iron-incorporated zeolites and determining their active centers for the direct oxidation of CH_4 to oxygenates have remained challenging topics so far.In this paper,we successfully prepare the hig...Developing effective iron-incorporated zeolites and determining their active centers for the direct oxidation of CH_4 to oxygenates have remained challenging topics so far.In this paper,we successfully prepare the highly-dispersed iron supported Y zeolites by a facile solid-state ion-exchange method with ferrocene,which was conducted under water-free conditions followed by a series of calcination.Moreover,extra-framework dinuclear Fe^(2+)complexes are identified as so-called activeα-iron sites on zeolites.ICP-OES,N_2 adsorption–desorption test,X-ray diffraction,solid-state^(27)Al NMR,N_2O titration,TEM,EPR and^(57)Fe M?ssbauer spectra were carried out to characterize properties of sample structure,acid sites,as well as the supported iron species.Characterization results indicate that high-temperature treatments have no effect on the typical structure feature of zeolites.Compared with catalysts synthesized by conventional impregnation,the samples prepared by the facile approach possess abundant dinuclear Fe^(2+)complexes but no Fe_2O_3 bulks and show weak acidity.These lead to a higher oxygenate selectivity in CH_4 oxidation to oxygenates.Remarkably,the oxygenate(HCHO and CH_3OH)selectivity of 6.5% at 375°C can be eventually obtained.展开更多
During the Cold War,China’s diplomacy failed to treat the Arab states as a whole.It was not until the end of the Cold War that China established diplomatic relations with all 22 Arab states.Since then,a multilateral ...During the Cold War,China’s diplomacy failed to treat the Arab states as a whole.It was not until the end of the Cold War that China established diplomatic relations with all 22 Arab states.Since then,a multilateral cooperation mechanism between China and Arab states has come into existence and become steadily developed.In 2004,the China-Arab States Cooperation Forum was established.In 2010,China and the Arab states announced the establishment of a strategic cooperative relationship.After the Gulf War,the Arab world entered a period of fragmentation and division.The situation deteriorated after the drastic changes in the Middle East in 2011,to the point of entering an era of granulation.The ability of The League of Arab States to operate as a single international actor has been greatly impaired.In the era of the fragmentation of the Arab world,the mechanism of multilateral cooperation between China and the Arab States has developed in spite of these great difficulties.In future,the role and function of the multilateral mechanism of cooperation between China and the Arab states needs to be clarified,and efficiency needs to be improved based on the existing mechanisms.展开更多
The year 2014 was a tipping point for the Barack Obama Administration--that was the year when it strove to forge a legacy of the Obarna era but came up against challenges arising from major changes that were taking pl...The year 2014 was a tipping point for the Barack Obama Administration--that was the year when it strove to forge a legacy of the Obarna era but came up against challenges arising from major changes that were taking place internationally and domestically. The Administration was then focused on maintaining a fragile balance between creating this legacy and responding to these challenges. Obama stuck to his fundamental principles when dealing with overseas affairs, but he also came up with new responses. The dynamic balance struck between these two formed the basis of the global strategy of the late-term Obama Administration. The Administration＇s focus at this time highlights the dilemma it faced in forging a legacy. Further, the foreign policy of Obama and Trump are actually not so different; they both supported some degree of isolationism with a focus on domestic issues.展开更多
The Inter-Parliamentary Union was formed in 1889, gathering, initially, 38 British and French parliamentarians. The IPU （guided, from 1901 up to 1908, by Fredreric Passy and William Randall Cremer）, was to support a...The Inter-Parliamentary Union was formed in 1889, gathering, initially, 38 British and French parliamentarians. The IPU （guided, from 1901 up to 1908, by Fredreric Passy and William Randall Cremer）, was to support and reinforce the objective of extending arbitration as a ＇peaceful tool＇ for resolving the dispute between states. The aftermath of the First World War marked a decisive step forward in the development of a strong liberal internationalist milieux which promoted a peaceful order based on the international rule of law. This paper summarizes some issues of ongoing research and it focuses on two key topics： the rise of parliamentary control of foreign policy and the making of ＇parliamentary diplomacy＇. Besides, it tried to elucidate, from another point of view, the political building of ＇transnational and peaceful politics＇ aimed at the growth of peaceful and ＇progressive＇ social relations among States and how the ＇peaceful politics＇ are subjects that engage the complexity and the deep-rooted issues of State facing to the ＇first globalization＇ and the ＇end of century crisis＇.展开更多
基金Support by the National Key R&D Program of China(2016YFA0202900)the National Natural Science Foundation of China(21622606)+2 种基金the Natural Science Foundation of Zhejiang Province(LR18B060001)Basic Research Project of Sinopec Group(415025)the Fundamental Research Funds for the Central Universities
文摘Developing effective iron-incorporated zeolites and determining their active centers for the direct oxidation of CH_4 to oxygenates have remained challenging topics so far.In this paper,we successfully prepare the highly-dispersed iron supported Y zeolites by a facile solid-state ion-exchange method with ferrocene,which was conducted under water-free conditions followed by a series of calcination.Moreover,extra-framework dinuclear Fe^(2+)complexes are identified as so-called activeα-iron sites on zeolites.ICP-OES,N_2 adsorption–desorption test,X-ray diffraction,solid-state^(27)Al NMR,N_2O titration,TEM,EPR and^(57)Fe M?ssbauer spectra were carried out to characterize properties of sample structure,acid sites,as well as the supported iron species.Characterization results indicate that high-temperature treatments have no effect on the typical structure feature of zeolites.Compared with catalysts synthesized by conventional impregnation,the samples prepared by the facile approach possess abundant dinuclear Fe^(2+)complexes but no Fe_2O_3 bulks and show weak acidity.These lead to a higher oxygenate selectivity in CH_4 oxidation to oxygenates.Remarkably,the oxygenate(HCHO and CH_3OH)selectivity of 6.5% at 375°C can be eventually obtained.
文摘During the Cold War,China’s diplomacy failed to treat the Arab states as a whole.It was not until the end of the Cold War that China established diplomatic relations with all 22 Arab states.Since then,a multilateral cooperation mechanism between China and Arab states has come into existence and become steadily developed.In 2004,the China-Arab States Cooperation Forum was established.In 2010,China and the Arab states announced the establishment of a strategic cooperative relationship.After the Gulf War,the Arab world entered a period of fragmentation and division.The situation deteriorated after the drastic changes in the Middle East in 2011,to the point of entering an era of granulation.The ability of The League of Arab States to operate as a single international actor has been greatly impaired.In the era of the fragmentation of the Arab world,the mechanism of multilateral cooperation between China and the Arab States has developed in spite of these great difficulties.In future,the role and function of the multilateral mechanism of cooperation between China and the Arab states needs to be clarified,and efficiency needs to be improved based on the existing mechanisms.
文摘The year 2014 was a tipping point for the Barack Obama Administration--that was the year when it strove to forge a legacy of the Obarna era but came up against challenges arising from major changes that were taking place internationally and domestically. The Administration was then focused on maintaining a fragile balance between creating this legacy and responding to these challenges. Obama stuck to his fundamental principles when dealing with overseas affairs, but he also came up with new responses. The dynamic balance struck between these two formed the basis of the global strategy of the late-term Obama Administration. The Administration＇s focus at this time highlights the dilemma it faced in forging a legacy. Further, the foreign policy of Obama and Trump are actually not so different; they both supported some degree of isolationism with a focus on domestic issues.
文摘The Inter-Parliamentary Union was formed in 1889, gathering, initially, 38 British and French parliamentarians. The IPU （guided, from 1901 up to 1908, by Fredreric Passy and William Randall Cremer）, was to support and reinforce the objective of extending arbitration as a ＇peaceful tool＇ for resolving the dispute between states. The aftermath of the First World War marked a decisive step forward in the development of a strong liberal internationalist milieux which promoted a peaceful order based on the international rule of law. This paper summarizes some issues of ongoing research and it focuses on two key topics： the rise of parliamentary control of foreign policy and the making of ＇parliamentary diplomacy＇. Besides, it tried to elucidate, from another point of view, the political building of ＇transnational and peaceful politics＇ aimed at the growth of peaceful and ＇progressive＇ social relations among States and how the ＇peaceful politics＇ are subjects that engage the complexity and the deep-rooted issues of State facing to the ＇first globalization＇ and the ＇end of century crisis＇.
