检索结果-南通市图书馆

CMIP5 Simulated Change in the Intensity of the Hadley and Walker Circulations from the Perspective of Velocity Potential

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2016年第7期33卷 808-818页

作者： Botao ZHOU ying shi ying XU National Climate Center China Meteorological Administration Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science & Technology

Based on the simulations of 31 global models in CMIP5, the performance of the models in simulating the Hadley and Walker circulations is evaluated. In addition, their change in intensity by the end of the 21st century （2080-2099） under the RCP4.5 and RCP8.5 scenarios, relative to 1986-2005, is analyzed from the perspective of 200 hPa velocity potential. Validation shows good performance of the individual CMIP5 models and the multi-model ensemble mean （MME） in re- producing the meridional （zonal） structure and magnitude of Hadley （Walker） circulation. The MME can also capture the observed strengthening tendency of the winter Hadley circulation and weakening tendency of the Walker circulation. Such secular trends can be simulated by 39% and 74% of the models, respectively. The MME projection indicates that the winter Hadley circulation and the Walker circulation will weaken under both scenarios by the end of the 21st century. The weak- ening amplitude is larger under RCP8.5 than RCP4.5, due to stronger external forcing. The majority of the CMIP5 models show the same projection as the MME. However, for the summer Hadley circulation, the MME shows little change under RCP4.5 and large intermodel spread is apparent. Around half of the models project an increase, and the other half project a decrease. Under the RCP8.5 scenario, the MME and 65% of the models project a weakening of the summer southern Hadley circulation.

关键词： Hadley circulation Walker circulation model evaluation CMIP5 projection velocity potential

Dynamics of a Function Related to the Primes

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2015年第1期36卷 81-90页

作者： ying shi Quanhui YANG Department of Mathematics Nanjing University of Traditional Chinese Medicine School of Mathematics and Statistics Nanjing University of Information Science and Technology

Let n = p1p2 ··· pk, where pi(1 ≤ i ≤ k) are primes in the descending order and are not all equal. Let Ωk(n) = P(p1 + p2)P(p2 + p3) ··· P(pk-1+ pk)P(pk+ p1), where P(n) is the largest prime factor of n. Define w0(n) = n and wi(n) = w(wi-1(n)) for all integers i ≥ 1. The smallest integer s for which there exists a positive integer t such thatΩs k(n) = Ωs+t k(n) is called the index of periodicity of n. The authors investigate the index of periodicity of n.

关键词： Dynamics The largest prime factor Arithmetic function

Theoretical investigation on the excited state intramolecular proton transfer in Me_(2)N substituted flavonoid by the time-dependent density functional theory method

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2018年第5期27卷 534-538页

作者： Hang Yin ying shi Institute of Atomic and Molecular Physics Jilin UniversityChangchun 130012China State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchun 130012China

Time-dependent density functional theory(TDDFT)method is used to investigate the details of the excited state intramolecular proton transfer(ESIPT)process and the mechanism for temperature effect on the Enol^(*)/Keto^(*)emission ratio for the Me_(2)N-substited flavonoid(MNF)*** geometric structures of the S_(0) and S_(1) states are denoted as the Enol,Enol^(*),and Keto*.In addition,the absorption and fluorescence peaks are also *** is noted that the calculated large Stokes shift is in good agreement with the experimental ***,our results confirm that the ESIPT process happens upon photoexcitation,which is distinctly monitored by the formation and disappearance of the characteristic peaks of infrared(IR)spectra involved in the proton transfer and in the potential energy ***,the calculations of highest occupied molecular orbital(HOMO)and lowest unoccupied molecular orbital(LUMO)reveal that the electronegativity change of proton acceptor due to the intramolecular charge redistribution in the S_(1) state induces the ***,the thermodynamic calculation for the MNF shows that the Enol^(*)/Keto^(*)emission ratio decreasing with temperature increasing arises from the barrier lowering of ESIPT.

关键词： time-dependent density functional theory excited state intramolecular proton transfer intramolecular charge transfer transition state

On the Equation n1n2= n3n4 Restricted to Factor Closed Sets

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2018年第10期34卷 1517-1530页

作者： San ying shi Michel WEBER School of Mathematics Hefei University of Technology Hefei 230009 P. R. China IRMA UMR 7501 7 rue Rend Descartes 67084 Strasbourg Cedex France

We study the number of solutions N（B,F） of the diophantine equation n1n2 = n3n4,where 1 ≤ n1≤B, 1≤ n3 ≤B, n2, n4 ∈ F and F C [1, B] is a factor closed set. We study more particularly the case when F = {m = p1^... 详细信息

关键词： Diophantine equation arithmetical functions factor closed set

Reagent Vibration Effect on the Stereodynamics for the C+CD→C2+D Reaction

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2011年第11期28卷 95-98页

作者： XIE Ting-Xian shi ying School of Science Dalian Jiaotong UniversityDalian 116028 Institute of Atomic and Molecular Physics Jilin UniversityChangchun 130012

We study the effect of the reagent vibration of the CD on the stereodynamics of the C+CD→C2+D reaction by using the quasi-classical trajectory method at a collision energy of 2.306 kcal/mol on the potential energy surface of the 12𝐴′state[Boggio-Pasqua et ***.98(2000)1925].The vector correlation distributions𝑝(θr)and the dihedral-angle distribution𝑝(Φr)as well as𝑝(θr,Φr)are *** addition,two polarizationdependent generalized differential cross sections of the product are presented and discussed within a center-ofmass *** results show that the effect of reagent vibration can cause obviously different effects on the stereodynamics of the title reaction.

关键词： reaction dynamics reagent

Assessment of Indices of Temperature Extremes Simulated by Multiple CMIP5 Models over China

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2015年第8期32卷 1077-1091页

作者： DONG Siyan XU ying ZHOU Botao shi ying National Climate Center China Meteorological Administration

Given that climate extremes in China might have serious regional and global consequences, an increasing number of studies are examining temperature extremes in China using the Coupled Model Intercomparison Project Phase 5 （CMIP5） models. This paper investigates recent changes in temperature extremes in China using 25 state-of-the-art global climate models participating in CMIP5. Thirteen indices that represent extreme temperature events were chosen and derived by daily maximum and minimum temperatures, including those representing the intensity （absolute indices and threshold indices）, duration （duration indices）, and frequency （percentile indices） of extreme temperature. The overall performance of each model is summarized by a ＂portrait＂ diagram based on relative root-mean-square error, which is the RMSE relative to the median RMSE of all models, revealing the multi-model ensemble simulation to be better than individual model for most indices. Compared with observations, the models are able to capture the main features of the spatial distribution of extreme temperature during 1986-2005. Overall, the CMIP5 models are able to depict the observed indices well, and the spatial structure of the ensemble result is better for threshold indices than frequency indices. The spread amongst the CMIP5 models in different subregions for intensity indices is small and the median CMIP5 is close to observations; however, for the duration and frequency indices there can be wide disagreement regarding the change between models and observations in some regions. The model ensemble also performs well in reproducing the observational trend of temperature extremes. All absolute indices increase over China during 1961-2005.

关键词： temperature extremes China CMIP5 model evaluation

单层Cs_(2)PbI_(2)Cl_(2)中点缺陷的形成与稳定性

在线全文

学校读者我要写书评

暂无评论

原子与分子物理学报 2025年第5期42卷 130-136页

作者：何诗颖赵宇清邹代峰许英廖雨洁禹卓良湖南科技大学物理与电子科学学院湘潭411201 智能传感器与新型传感器材料湖南省重点实验室湘潭411201 湖南理工学院物理与电子科学学院岳阳414006

Cs_(2)PbI_(2)Cl_(2)是卤化铅钙钛矿材料的新成员,由于其高的光吸收系数和长的载流子迁移距离等优异的光电物理性能,在太阳能电池、光电探测器、场效应晶体管以及发光二极管等领域受到广泛的关注.其中光电材料及器件的优良特性由电子结... 详细信息

Cs_(2)PbI_(2)Cl_(2)是卤化铅钙钛矿材料的新成员,由于其高的光吸收系数和长的载流子迁移距离等优异的光电物理性能,在太阳能电池、光电探测器、场效应晶体管以及发光二极管等领域受到广泛的关注.其中光电材料及器件的优良特性由电子结构决定,而钙钛矿的点缺陷对电子结构具有重要的调控,且单层Cs_(2)PbI_(2)Cl_(2)中点缺陷的研究尚且缺乏.本文基于密度泛函理论的第一性原理计算,对单层Cs_(2)PbI_(2)Cl_(2)的铯空位、碘空位、氯空位、铯替代铅、碘替代铯、碘替代铅、碘替代氯、氯替代铯、氯替代铅和氯替代碘的缺陷形成能和稳定性进行了研究.结果表明:在富铅和缺铅条件下,碘替代氯和氯替代碘的缺陷形成能偏低,且氯替代碘能有效降低体系总能,提高体系稳定性.在缺铅条件下铯空位缺陷形成能低于富铅条件,在缺铅条件下更易形成铯空位;富铅和缺铅条件下对碘替代氯和氯替代碘的缺陷形成能基本无影响.上述研究结果有助于理解点缺陷对钙钛矿材料稳定性的影响,同时也为未来实验上设计基于Cs_(2)PbI_(2)Cl_(2)的高效的光电子器件提供理论依据.

关键词：单层Cs_(2)PbI_(2)Cl_(2) 形成能点缺陷稳定性

Triplet excitation dynamics of β-carotene studied in three solvents by ns flash photolysis spectroscopy

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2017年第1期28卷 83-88页

作者： ying Jia ying shi Peng Wang Jian-Ping Zhang Department of Chemistry Renmin University of China Beijing 100872 China

Upon anthracene-sensitizing, triplet excitation dynamics of β-carotene（β-Car） were studied in nhexane, in methanol, and in acetonitrile, respectively, by ns flash photolysis spectroscopy. In n-hexane,only the bleaching of the ground state absorption（GSB） and the excitation triplet（^3Car＊） absorption were observed, and there were no cationic species detected. In both methanol and acetonitrile, similar excitation dynamics were observed, i.e.,^3Car＊ having a similar lifetime to that in n-hexane, and the immediate generation of the cation dehydrodimer（^#[Car]2^＋） upon excitation following transformation into the radical cation Car＊^＋, since Car＊^＋ has much longer lifetime in acetonitrile than in methanol. The results prove that both solvent and carotenoid structure determine the triplet excitation mechanism.

关键词： β-Carotene Triplet excitation dynamics Solvent effect ns Flash photolysis

在线全文

学校读者我要写书评

暂无评论

体相二硫化铼中点缺陷的形成与稳定性

原子与分子物理学报 2025年第5期42卷 143-150页

二硫化铼是过渡金属二硫族化合物的成员,由于层间的范德华作用、合适的带隙、高的光吸收系数和长的载流子迁移距离在光电子研究领域引起广泛的关注.其中光电材料及器件的优良特性由电子结构决定,而半导体的缺陷能级对电子结构具有重要... 详细信息

二硫化铼是过渡金属二硫族化合物的成员,由于层间的范德华作用、合适的带隙、高的光吸收系数和长的载流子迁移距离在光电子研究领域引起广泛的关注.其中光电材料及器件的优良特性由电子结构决定,而半导体的缺陷能级对电子结构具有重要的调控,且体相二硫化铼的缺陷研究尚且缺乏.本文基于密度泛函理论的第一性原理计算,对体相二硫化铼的铼空位、硫空位、钨掺杂(或替代)铼、钨掺杂硫、锝掺杂铼和锝掺杂硫的缺陷形成能和稳定性进行了研究.结果表明:钨掺杂硫和锝掺杂硫形成深施主能级缺陷,铼空位形成浅施主能级缺陷.在富铼和富硫条件下,钨掺杂铼的缺陷形成能低且能有效降低体系总能,提高体系稳定性.钨掺杂硫的缺陷虽然能降低体系的总能提高二硫化铼的稳定性,但较大的缺陷形成能表明钨掺杂硫缺陷难以形成.上述研究结果有助于理解缺陷能级对半导体深浅能级和稳定性的影响,同时也为未来实验上设计基于二硫化铼的高效的光电子器件提供理论依据.

关键词：体相二硫化铼形成能缺陷能级稳定性