检索结果-南通市图书馆

Thienothiophene-centered ladder-type π-systems that feature distinct quinoidal π-extension

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第5期35卷 249-253页

作者： Jiaxiang Guo Zeyi Li Tianyu Zhang Xinyu Tian Yue Wang Chuandong dou State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchun 130012China Jiangsu Engineering Laboratory of Novel Functional Polymeric Materials Soochow UniversitySuzhou 215123China

Quinoidalπ-conjugated structures,a kind of fundamental subunits for organicπ-systems,may produce some intriguing optical,electronic and magnetic properties of polycyclic hydrocarbons(PHs).Herein,we report two thienothiophene-centered ladder-type polycyclic molecules(1 and 2),which possess one quinoidal thienothiophene moiety and two para-quinodimethane(p-QDM)subunits,*** theoretically and experimentally studied,while 1 is a fully closed-shell molecule,2 owns an open-shell structure along with partial contribution of tetraradical state that is induced by the resonance of ***,although 2 has a largerπ-conjugated skeleton and open-shell electronic state,it exhibits larger bandgap and blue-shifted *** the other hand,the reversible oxidation activity of 1 enables the preparation of its dication 1^(2+),and the studies on its single-crystal and aromatic structures demonstrate that its two positive charges are delocalized onto the oxygen atoms,thus achieving fullyπ-extended structure and near-infrared *** study not only gains insight into quinoidalπ-subunits,but also provides an important basis for the development of antiaromatic and open-shellπ-electron materials.

关键词： Thienothiophene Quinoidal conjugation Open-shell structure Aromaticity Photophysical properties

Selectivity switch via tuning surface static electric field in photocatalytic alcohol conversion

在线全文

学校读者我要写书评

暂无评论

The Innovation 2024年第5期5卷 55-62,54页

作者： Zhiwei Chen hongru Zhou Fanhao Kong Zhaolin dou Min Wang State Key Laboratory of Fine Chemicals School of ChemistryDalian University of TechnologyDalian 116024China

Photocatalysis has shown great potential in organic reactions,while controlling the selectivity is a long-standing goal and challenge due to the involvement of various radical *** this study,we have realized selectivity control in the photocatalytic conversion of alcohols via engineering the surface static electric field of the CdS *** leveraging the Au–CdS interaction to adjust lattice strain,which influences the intensity of the surface static electric field,we altered the pathways of alcohol *** increased intensity of the surface static electric field changed the activation pathways of the C–H/O–H bond,leading to the selective formation of targeted C/O-based radical intermediates and altering the selectivity from aldehydes to dimers.A wide range of alcohols,such as aromatic alcohol and thiophenol alcohol,were selectively converted into aldehyde or *** work provides an effective strategy for selectively controlling reaction pathways by generating a surface electric field.

关键词： field. alcohol selectivity

Enhancing stability of diradical polycyclic hydrocarbons via P=O-attaching

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

Chinese Chemical Letters 2024年第8期35卷 309-313页

作者： jingyuan Yang Xinyu Tian Liuzhong Yuan Yu Liu Yue Wang Chuandong dou State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchun 130012China Jiangsu Engineering Laboratory of Novel Functional Polymeric Materials Soochow UniversitySuzhou 215123China

Diradical polycyclic hydrocarbons(PHs)have unique open-shell structures and interesting physical ***,owing to high reactivity of unpaired electrons,such open-shell organic diradicaloids are usually less stable than closed-shell systems,limiting their practical *** this study,we report P=O-attaching of diradical PHs as a new strategy to enhance their stability while maintaining diradi-cal *** P=O-attached PHs containing the indeno[1,2-b]fluorene,fluoreno[3,2-b]fluorene and indeno[2,1-b]fluoreneπ-skeletons,respectively,were designed and *** theoretically and ex-perimentally proved,two of them have the relatively large diradical characters and open-shell singlet diradical *** comparison to their all-carbon analogues,the attached electron-withdrawing P=O groups endow them with much lower LUMO/HOMO energy levels but preserved magnetic activities and physical properties,such as thermally accessible triplet species and multi-redox ***,the P=O groups effectively decrease their oxidation activities and thereby lead to their remarkably excellent ambient ***,this P=O-attaching strategy will be applicable to other diradical PH systems and may promote the generation of stable organic diradicaloids for radical chemistry and materials.

关键词： Polycyclic hydrocarbons Open-shell structure Diradical character Stability Oxidation activity

Luminescent metal-halide perovskites:fundamentals,synthesis,and light-emitting devices

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第6期67卷 1776-1838页

作者： Kang Wang Jeong Hui Kim Jie Yang Xiaoke Liu Yixuan dou Yuxuan Li Weijian Tao Haiyun Dong Haiming Zhu Kaifeng Wu Li Na Quan Feng Gao Jianpu Wang Letian dou Yong Sheng Zhao Beijing National Laboratory for Molecular Sciences(BNLMS) Key Laboratory of PhotochemistryInstitute of ChemistryChinese Academy of SciencesBeijing100190China Davidson School of Chemical Engineering Purdue UniversityWest LafayetteIN47907USA School of Chemical Sciences University of Chinese Academy of SciencesBeijing100049China Key Laboratory of Flexible Electronics(KLOFE) Institute of Advanced Materials(IAM)&School of Flexible Electronics(Future Technologies)Nanjing Tech University(NanjingTech)Nanjing211816China Department of Physics Linköping UniversityLinköping58183Sweden Department of Chemistry Virginia TechBlacksburgVA24060USA State Key Laboratory of Molecular Reaction Dynamics Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian116023China Department of Chemistry Zhejiang UniversityHangzhou310058China Changzhou University Changzhou213164China Department of Chemistry Purdue UniversityWest LafayetteIN47907USA

Metal-halide perovskites have garnered considerable research attention as highly efficient light emitters in recent years due to their outstanding optoelectronic properties with remarkable tunability and excellent solution *** advancements have been achieved in the development of novel halide perovskites,and the exploitations of these materials in lightemitting *** review comprehensively outlines recent breakthroughs in metal-halide perovskites,encompassing the rational design of perovskite materials with tunable light emission properties,the controllable growth of single crystal for a deeper understanding of their structure-property relationships,as well as the fundamental insights into the photophysics and carrier dynamics in perovskite ***,it provides an overview of recent applications of perovskite materials in high-performance light-emitting diodes(LEDs)and lasers.

关键词： metal-halide perovskites perovskite luminescent materials perovskite synthesis excited-state processes perovskite light-emitting diodes perovskite lasers

CO_(2) corrosion of X80 steel welded joints under micro-turbulence induced by welding reinforcement height

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第4期31卷 1015-1032页

作者： Xiao-hui dou Bin Li Zong-hao He Xin-wei Zhang Da-lei Zhang Yan Li School of Materials Science and Engineering China University of Petroleum(East China)Qingdao 266580ShandongChina School of Energy and Power Engineering Jiangsu UniversityZhenjiang 212013JiangsuChina

Corrosion failure accidents owing to flow erosion and pipeline corrosion frequently occur during *** welding reinforcement height(WRH)can induce locally micro-turbulent flow field,which aggravates local corrosion of welded joints.A high wall shear stress(WsS)experimental setup was established to conduct the online electrochemical corrosion *** influence of WRH sizes on local corrosion of welded joints was studied at different flow *** electrochemical signals of the local corrosion of X80 welded joints at different flow rates were monitored in real time using electrochemical impedance spectroscopy and wire beam *** addition,the corrosion products composition and properties were *** results show that the micro-turbulent flow fields induced by the WRHs can enhance ion mass transfer near the welded *** corrosion products on the WRH surface also present different microscopic morphologies at different flow *** strong flow fields,the locally enhanced wsS can peel off the dense corrosion product partially,leading to the electrochemical distribution of large cathode and small anode,which accelerates the occurrence and development processes of the local corrosion of welded *** scientific guidelines for the corrosion protection of long-distance oil and gas pipelines can be potentially provided.

关键词： X80 steel welded joint Welding reinforcement height Micro-turbulence CO_(2)corrosion-Ion mass transfer

Wave Attenuation and Turbulence Driven by Submerged Vegetation Under Current-Wave Flow

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

China Ocean Engineering 2024年第4期38卷 602-611页

作者： HUANG Yu-ming Ding Lei WANG Yi-fei CHEN Ben YANG Xiao-yu dou Xi-ping School of Water Resources and Hydropower Engineering Wuhan UniversityWuhan430072China Key Laboratory of Port Waterway and Sedimentation Engineering of MOTNanjing Hydraulic Research InstituteNanjing 210029China

A set of laboratory experiments are carried out to investigate the effect of following/opposing currents on wave *** vegetation canopies with aligned and staggered configurations were tested under the condition of various regular wave heights and current velocities,with the constant water depth being 0.60 m to create the desired submerged *** show that the vegetation-induced wave dissipation is enhanced with the increasing incident wave height.A larger velocity magnititude leads to a greater wave height attenuation for both following and opposing current ***,there is a strong positive linear correlation between the damping coefficientβand the relative wave height H_(0)/h,especially for pure wave *** the velocity profile,the distributions of U_(min)and U_(max)show different patterns under combined wave and *** time-averaged turbulent kinetic energy(TKE)vary little under pure wave and U_(c)=±0.05 m/s *** the increase of flow velocity amplitude,the time-averaged TKE shows a particularly pronounced increase trend at the top of the *** vegetation drag coefficients are obtained by a calibration *** empirical relations of drag coefficient with Reynolds and Keulegane-Carpenter numbers are proposed to further understand the wave-current-vegetation interaction mechanism.

关键词： wave attenuation rigid vegetation following and opposing currents turbulent kinetic energy

Responses of nitrogen cycling and related microorganisms to brackish wetlands formed by evapotranspiration

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2024年第1期34卷 252-266页

作者： Jiaohui FANG Tianshu LU Jian LIU Shangbin HE Xiufeng YANG Huashan dou honghai ZHANG School of Life Sciences Qufu Normal UniversityQufu 273100China Environment Research Institute Shandong UniversityQingdao 266237China Hulunbuir Academy of Inland Lakes in Northern Cold&Arid Areas Hulunbuir 021000China

Elevated evapotranspiration due to warmer air temperature could raise salinity and nutrient levels of some inland wetlands, potentially impacting nitrogen cycling. To characterize the impact of high evapotranspiration on soil microbial nitrogen cycling in inland wetlands, we compared freshwater and brackish marsh(or non-marsh) wetlands in terms of sediment ammonia-oxidizing rate(AOR), denitrifying rate(DR), and related microbial communities in a typical inland basin, the Hulun Lake basin, in China. Results showed that marsh ecosystems(ME) exhibited 31% higher AOR and 65% higher DR than non-marsh ecosystems(NE). For NE, freshwater non-marsh wetland exhibited 12% higher AOR than brackish non-marsh wetland. This was probably due to the inhibitory effects of high NH_4~+ and salinity levels on ammonia-oxidizing archaea in brackish non-marsh wetland. Conversely, DR in brackish non-marsh wetland was 23% higher than that in freshwater non-marsh wetland, with total organic carbon(TOC) significantly influencing this difference,suggesting that the higher DR in brackish non-marsh wetland was mainly due to its higher TOC level. For ME, due to the direct and indirect interference of salinity, brackish marsh wetland displayed 26% lower AOR and 19% lower DR than freshwater marsh wetland. Besides, brackish wetlands harbored distinct ammonia-oxidizing and denitrifying microbial communities compared to freshwater wetlands. The assembly of these communities was dominated by stochastic processes, while brackish wetlands exhibited more prominent deterministic processes than freshwater wetlands. Overall, high evapotranspiration altered activities and community characteristics of ammonia oxidizers and denitrifiers in inland brackish wetlands by enhancing salinity and nutrient levels,while emergent plants occurring in ME could mitigate the adverse effects of salt stress of inland brackish wetlands on nitrogen cycling.

关键词： ammonia-oxidizing archaea ammonia-oxidizing bacteria aquatic plants denitrifying bacteria nitrogen transformation inland wetlands

On the Shallowing of Antarctic Low-Level Temperature Inversions Projected by CESM-LE under RCP8.5

在线全文

学校读者我要写书评

暂无评论

Journal of Meteorological Research 2024年第3期38卷 586-599页

作者： Minghu DING Lin ZHANG Tingfeng dou Yi HUANG Yingyan LUO Junmei LYU Cunde XIAO State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing100081China Key Laboratory of Meteorology and Ecological Environment of Hebei Province Hebei Provincial Institute of Meteorological SciencesShijiazhuang050021China College of Resources and Environment University of Chinese Academy of SciencesBeijing100049China State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing100875China

Temperature inversions are frequently observed in the boundary layer and lower troposphere of polar *** variations of the low-level temperature inversions in these regions,especially the Antarctic,are still poorly *** to the scarcity of observations in the Antarctic,reanalysis data and numerical simulations are often used in the study of Antarctic climate *** on ERA-Interim,ERA5,JRA-55,and NCEP-NCAR reanalysis products,this study examines temporal and spatial variations of Antarctic inversion depth in austral autumn and winter during *** inversions are found to occur over the high plateau areas of the Antarctic *** on the Mann-Kendall test,ERA-Interim and ERA5 data reveal that the Antarctic inversion depth in austral autumn and winter increased during 1992-2007,roughly maintained afterwards,and then significantly decreased since around *** decrease trend is more obvious in the last two months of ***,JRA-55 better represents the spatial distribution of inversion depth,and ERA-Interim has better interannual *** Community Earth System Model Large Ensemble(CESM-LE)30-member simulations in 1979-2005 were first verified against JRA-55,showing reasonable consistency,and were then used to project the future changes of Antarctic low-level inversion depth over 2031-2050 under *** CESM-LE projection results reveal that the temperature inversion will shallow in the Antarctic at the end of the 21st century,and the decrease in depth in autumn will be more pronounced than that in *** particular,the temperature inversion will weaken over the ice-free ocean,while it will remain stable over the ice sheet,showing certain spatial heterogeneity and seasonal dependence on the underlying cryospheric surface *** addition,the decrease of inversion depth is found closely linked with the reduction in sea ice,suggesting the strong effect of global warming on the thermal structure change o

关键词： boundary layer temperature inversion Antarctic climate change Community Earth System Model Large Ensemble(CESM-LE)

The first factor affecting dryland winter wheat grain yield under various mulching measures: Spike number

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2024年第3期23卷 836-848页

作者： Yingxia dou Hubing Zhao Huimin Yang Tao Wang Guanfei Liu Zhaohui Wang Sukhdev Malhi Coliege of Natural Resources and Environment Northwest A&F UniversityYangling 712100China Key Laboratory of Plant Nutrition and the Agri-Environment in Northwest China Ministry of Agriculture and Rural AffairsYangling 712100China Department of Renewable Resources University of AlbertaEdmonton T6G 2H1Canada

Water is the key factor limiting dryland wheat grain *** affects crop yield and yield components by affecting soil *** research is needed to determine the relationships between yield components and soil moisture with yield,and to identify the most important factor affecting grain yield under various mulching measures.A long-term 9-yearifeld experiment in the Loess Plateau of Northwest China was carried out with three treatments:no mulch (CK),plastic mulch (M_(P)) and straw mulch (M_(S)).Yield factors and soil moisture were measured,and the relationships between them were explored by correlation analysis,structural equation modeling and significance *** results showed that compared with CK,the average grain yields of M_(P) and M_(S) increased by 13.0and 10.6%,*** average annual grain yield of the M_(P) treatment was 134 kg ha^(–1) higher than the M_(S) *** were no significant differences in yield components among the three treatments (P<0.05).Soil water storage of the M_(S) treatment was greater than the M_(P) treatment,although the differences were not statistically *** water storage during the summer fallow period (SWSSF) and soil water storage before sowing (SWSS) of M_(S) were significantly higher than in CK,which increased by 38.5 and 13.6%,*** relationship between M_(P) and CK was not statistically significant for SWSSF,but the SWSS in M_(P) was significantly higher than in *** terms of soil water storage after harvest (SWSH) and water consumption in the growth period(ET),there were no signi?cant differences among the three *** on the three analysis methods,we found that spike number and ET were positively correlated with grain ***,the relative importance of spike number to yield was the greatest in the M_(P )and M_(S) treatments,while that of ET was the greatest in *** SWSSF could indirectly increase spike number and ET in the three treatments.B

关键词： dryland winter wheat plastic mulch spike number straw mulch