Accurately known energy level structure of the A＇∑u＋b3 IIu complex of states from a recent global de-perturbation of these states has enabled additional assignments of 140 perturbation facilitated infrared-infrared...Accurately known energy level structure of the A＇∑u＋b3 IIu complex of states from a recent global de-perturbation of these states has enabled additional assignments of 140 perturbation facilitated infrared-infrared double resonance （PFIIDR） transitions to the 2^3△1g state from collisionally populated intermediate 1 ＋ A Eu levels. Together with the 221 previously observed 2^3△1g←A1∑u＋←X1∑g＋ Eu X Eg double resonance lines [J. Chem. Phys. 128, 204313 （2008）], molecular constants and the Rydberg-Klein-Rees potential energy curve of the 23△1g state have been recalculated （excluding 54 perturbed levels）. The centrifugal distortion constant has been determined and agrees well with the value calculated based on standard empirical formulas. The hyperfine structure of the 23△1g state, which has not resolved in our sub-Doppler excitation spectra of the 23△1g state, has been interpreted with a preliminary simulation.展开更多
Joseph Heller(1923-1999)’s celebrated novel Catch-22(1961)portrays the predicament of an individual,Captain John Yossarian of the 256th US Army Air Squadron,drifting apart in a helpless prodigious world.The absurdity...Joseph Heller(1923-1999)’s celebrated novel Catch-22(1961)portrays the predicament of an individual,Captain John Yossarian of the 256th US Army Air Squadron,drifting apart in a helpless prodigious world.The absurdity and ludicrousness of the reconstructed world is strengthened by the elements of space in the narrative text.Drawing on Gabriel Zoran’s model of structuring of space within the fictional world,this essay analyzes the three levels of the structuring of space,namely the topographical level,the chronotopic level,and the textual level,and their functions in the novel.Topographical structures magnify the despair and deadly threats prevalent during wartime,whereas chronotopic structures underscore individual’s active endeavours and spiritual renewal in the face of institutional coercion.Textual structures,with three aspects of the text,the essential selectivity of language,the linearity of the text,and the point of view,bring forward the picture of the personal agony embedded in the grand establishment.展开更多
实验以两步晶化法,利用MCM-22沸石结构前驱体合成一种含介孔的催化材料,用XRD、N_2吸附-脱附、^(27)Al MAS NMR、NH_3-TPD对试样进行了表征。实验结果表明其孔径约为3.3 nm,比表面积为740～870m^2/g,其氢型试样除含有弱酸中心外,还含有...实验以两步晶化法,利用MCM-22沸石结构前驱体合成一种含介孔的催化材料,用XRD、N_2吸附-脱附、^(27)Al MAS NMR、NH_3-TPD对试样进行了表征。实验结果表明其孔径约为3.3 nm,比表面积为740～870m^2/g,其氢型试样除含有弱酸中心外,还含有强酸中心,总酸量为0.71～0.76 mmol/g。在115℃条件下,试样用于催化2,4-二叔丁基苯酚与叔丁基醇烷基化反应时,2,4-二叔丁基苯酚的转化率约为22%,2,4,6-三叔丁基苯酚的选择性约为49%,其催化活性高于微孔沸石Hβ和常规介孔分子筛HMCM-41。展开更多
文摘Accurately known energy level structure of the A＇∑u＋b3 IIu complex of states from a recent global de-perturbation of these states has enabled additional assignments of 140 perturbation facilitated infrared-infrared double resonance （PFIIDR） transitions to the 2^3△1g state from collisionally populated intermediate 1 ＋ A Eu levels. Together with the 221 previously observed 2^3△1g←A1∑u＋←X1∑g＋ Eu X Eg double resonance lines [J. Chem. Phys. 128, 204313 （2008）], molecular constants and the Rydberg-Klein-Rees potential energy curve of the 23△1g state have been recalculated （excluding 54 perturbed levels）. The centrifugal distortion constant has been determined and agrees well with the value calculated based on standard empirical formulas. The hyperfine structure of the 23△1g state, which has not resolved in our sub-Doppler excitation spectra of the 23△1g state, has been interpreted with a preliminary simulation.
文摘Joseph Heller(1923-1999)’s celebrated novel Catch-22(1961)portrays the predicament of an individual,Captain John Yossarian of the 256th US Army Air Squadron,drifting apart in a helpless prodigious world.The absurdity and ludicrousness of the reconstructed world is strengthened by the elements of space in the narrative text.Drawing on Gabriel Zoran’s model of structuring of space within the fictional world,this essay analyzes the three levels of the structuring of space,namely the topographical level,the chronotopic level,and the textual level,and their functions in the novel.Topographical structures magnify the despair and deadly threats prevalent during wartime,whereas chronotopic structures underscore individual’s active endeavours and spiritual renewal in the face of institutional coercion.Textual structures,with three aspects of the text,the essential selectivity of language,the linearity of the text,and the point of view,bring forward the picture of the personal agony embedded in the grand establishment.
文摘实验以两步晶化法,利用MCM-22沸石结构前驱体合成一种含介孔的催化材料,用XRD、N_2吸附-脱附、^(27)Al MAS NMR、NH_3-TPD对试样进行了表征。实验结果表明其孔径约为3.3 nm,比表面积为740～870m^2/g,其氢型试样除含有弱酸中心外,还含有强酸中心,总酸量为0.71～0.76 mmol/g。在115℃条件下,试样用于催化2,4-二叔丁基苯酚与叔丁基醇烷基化反应时,2,4-二叔丁基苯酚的转化率约为22%,2,4,6-三叔丁基苯酚的选择性约为49%,其催化活性高于微孔沸石Hβ和常规介孔分子筛HMCM-41。
