The Numerical Simulation of the Climatic Change Caused by CO_2 Doubling

The IAP two-level atmospheric general circulation model was coupled to a 60-m-deep mixed layer ocean model and a zero-layer thermodynamic model to simulate the climatic effects induced by a doubling of CO_2 concentration in the atmosphere.The global surface temperature is 1.75℃ when CO_2 is doubled. This value is lower than most of other results in the world, such as those of GFDL, NCAR, UKMO, GISS and OSU models.There are large regional and seasonal differences in the climatic change. Great warming is found in the Northern Hemisphere's high-latitude region anti the Antarctica; and the warming in land areas is greater than in ocean areas, while the precipitation increases in high latitudes and tropical regions but decreases in subtropical regions. In both hemispheres, the warming is greater in winter than in other seasons. As for the changes in China, we find that the precipitation in southwestern and northern China greatly decreases in summer but increases in winter.     

Solvent effects on competitive intramolecular electron transfer and energy transfer in a covalently linked porphyrin-phthalocyanine heterodimer

Photophysical properties of a porphyrin-phthalocyanine heterodimer covalently linked with a dipentoxy chain have been studied.Absorption spectra show that there is weak exciton coupling between the two chromophores in the ground state.Fluorescence spectra show that intramolecular energy transfer from porphyrin to phthalocyanine moiety occurs in competition with electron transfer.The efficiency of these two processes depends upon the mutual orientation of the two chromophores.The effect of solvent polarity on the intramolecular processes is also discussed.     

阴离子硫氧化还原与Li1-xNiO2-ySy的结构稳定性:第一性原理研究

Ni-rich layered oxides are the preferred cathode materials for high-energy-density lithium-ion batteries currently used in electric vehicles. In this paper, we present a systematic first-principles evaluation of the deintercalation process in the Li_1-xNiO_2-yS_y. The partial density of states (PDOS) characters of the electrons near the Fermi level, redox behaviors, and thermal stability have been investigated within the GGA+U scheme. The results show that the introduction of sulfur alleviates the lattice distortion during charging, suppresses nickel migration, and enhances the stability of oxygen according to the contribution of sulfur anion redox to the charge compensation for the overcharged Li_1-xNiO_2-yS_y. This study provides a new insight on improving the stability of Ni-rich cathode materials by tuning of the electrochemical behaviors based on sulfur anion redox.     

基于(火积)耗散率最小的复杂肋片对流换热构形优化

基于构形理论, 以基于(火积)耗散率定义的当量热阻最小为优化目标对复杂肋片进行构形优化, 得到同时考虑肋片导热和对流换热(火积)耗散性能的肋片最优构形, 并比较不同形状和不同优化目标下的肋片最优构形. 结果表明: 存在最佳单元级直肋、中部空腔以及肋片末梢高度和长度比使得复杂肋片当量热阻取得三重最小值. 当量热阻最小的复杂肋片最优构形与T-Y形肋片最优构形相比, 复杂肋片结构使得肋片整体传热性能大大提高. 当肋片传热为二维传热且根部较宽时, 肋片根部温度越不均匀, 当量热阻最小和最大热阻最小的复杂肋片最优构形差别越大. 在保证热安全性的前提下, 工程上对肋片进行优化设计时可选择当量热阻最小的肋片构形设计方案以降低其平均传热温差、提高整体传热性能. 本文从传热优化角度为复杂肋片的优化设计提供了参考.     

基于(火积)理论的轧钢加热炉壁变截面绝热层构形优化

基于绝热过程(火积)耗散极值原理, 分别在对流传热和复合传热(对流和辐射传热)边界条件下, 对轧钢加热炉壁变截面绝热层进行构形优化, 得到(火积)耗散率最小的绝热层最优构形. 结果表明: 与等截面绝热层相比, (火积)耗散率最小的变截面绝热层整体绝热性能更优. 热损失率最小和(火积)耗散率最小的绝热层最优构形是不同的. 热损失率最小的绝热层最优构形使得其能量损失减小, 而(火积)耗散率最小的绝热层最优构形使得其整体绝热性能提高. (火积)耗散率最小和最大温度梯度最小的变截面绝热层最优构形差别较小, 此时(火积)耗散率最小的绝热层最优构形在提高绝热层整体绝热性能的同时也提高了其热安全性. 基于(火积)理论的绝热层构形优化为绝热系统的优化设计提供了新的指导.     

Puqienine F, a novel veratramine alkaloid from the bulbs of Fritillaria puqiensis

A novel veratramine alkaloid, called puqienine F (1) and possessing a 12,16-epoxy ring, was isolated from the bulbs of Fritillaria puqiensis G. D. Yu et G. Y. Chen (Liliaceae). The structure was elucidated by extensive spectral and X-ray crystallographic analyses.     

亚甲基蒽苯乙烯吡啶盐的合成、结构及双光子吸收性质

以氯化4-甲基-N-9-亚甲基蒽吡啶盐为原料,合成了一种新型的苯乙烯吡啶盐,通过红外、核磁共振氢谱、碳谱、电喷雾质谱、单晶X射线衍射等测试技术对化合物的结构进行了表征。单晶X射线衍射结果表明,该化合物属于单斜晶系,空间群为P21/c,晶胞参数a=1.255 7(1)nm,b=1.539(1)nm,c=2.220 2(8)nm,β=101.099(1)°,V=4.210 5(4)nm3,Z=4,Dc=1.159 g/cm3。用1 064 nm皮秒脉冲激光研究其三阶非线性光学特性,双光子吸收系数β=0.028 cm/GW,吸收截面为σ=8.68×10-48cm4.s.photon-1,表明目标化合物具有良好的三阶非线性光学性质。     

四乙铵离子对阴离子表面活性剂及其混合体系的表面活性和胶团形成的影响

研究了溴化四乙铵介质中十二烷基硫酸四乙铵、全氟辛基磺酸四乙铵及其混合体系的表面化学性质。四乙铵离子在浓度较小时主要起电解质反离子作用,在浓度较大时则明显参与表面吸附和胶团的形成,其作用相当于在表面活性离子的疏水链上“引入”碳氢链,从而导致表面活性提高和碳氢/碳氟表面活性剂混合体系中碳氢/碳氟链间的互疏作用减弱等。     

聚酰胺-胺型树枝状高分子水溶液的表面活性

树枝状化合物是一类三维的、高度有序的新型高分子.与传统高分子相比,这类化合物在合成时,可以在分子水平上严格控制,设计分子大小、形状、结构和功能基团,产物一般高度对称,单分散性好.因而具有广泛的潜在用途^[1,2].近年来,已引起广大化学工作者的重视.