检索结果-南通市图书馆

Near infrared emissions from both high efficient quantum cutting (173%) and nearly-pure-color upconversion in NaY(WO_(4))_(2):Er^(3+)/Yb^(3+) with thermal management capability for silicon-based solar cells

引用

Light(Science & Applications) 2024年第1期13卷 113-126页

作者： duan gao Baojiu Chen Xuezhu Sha Yuhang Zhang Xin Chen Li Wang Xizhen Zhang Jinsu Zhang Yongze Cao Yichao Wang Lei Li Xiangping Li Sai Xu Hongquan Yu Lihong Cheng School of Science Dalian Maritime UniversityDalian 116026 LiaoningChina

Raising photoelectric conversion efficiency and enhancing heat management are two critical concerns for siliconbased solar cells.In this work,efficient Yb^(3+) infrared emissions from both quantum cutting and upconversion were demonstrated by adjusting Er^(3+) and Yb^(3+) concentrations,and thermo-manage-applicable temperature sensing based on the luminescence intensity ratio of two super-low thermal quenching levels was discovered in an Er^(3+)/Yb^(3+) codoped tungstate system.The quantum cutting mechanism was clearly decrypted as a two-step energy transfer process from Er^(3+) to Yb^(3+).The two-step energy transfer efficiencies,the radiative and nonradiative transition rates of all interested 4 f levels of Er^(3+) in NaY(WO_(4))_(2) were confirmed in the framework of Föster-Dexter theory,Judd-Ofelt theory,and energy gap law,and based on these obtained efficiencies and rates the quantum cutting efficiency was furthermore determined to be as high as 173%in NaY(WO_(4))_(2):5 mol%Er^(3+)/50 mol%Yb^(3+) sample.Strong and nearly pure infrared upconversion emission of Yb3+under 1550 nm excitation was achieved in Er^(3+)/Yb^(3+)co-doped NaY(WO_(4))_(2) by adjusting Yb^(3+) doping concentrations.The Yb^(3+) induced infrared upconversion emission enhancement was attributed to the efficient energy transfer ^(4)I_(11/2)(Er^(3+))+^(2)F_(7/2)(Yb^(3+))→^(4)I_(15/2)(Er^(3+))+^(2)F_(5/2)(Yb^(3+))and large nonradiative relaxation rate of ^(4)I_(9/2).Analysis on the temperature sensing indicated that the NaY(WO_(4))_(2):Er^(3+)/Yb^(3+)serves well the solar cells as thermos-managing material.Moreover,it was confirmed that the fluorescence thermal quenching of ^(2)H_(11/2)/^(4)S_(3/2) was caused by the nonradiative relaxation of ^(4)S_(3/2).All the obtained results suggest that NaY(WO_(4))_(2):Er^(3+)/Yb^(3+) is an excellent material for silicon-based solar cells to improve photoelectric conversion efficiency and thermal management.

关键词： quantum thermal relaxation

来源：

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 bio-inspired electrocatalysts for clean energy future

引用

Nano Research 2024年第2期17卷 515-533页

作者： Jing-Wen duan Mu Min-Rui gao Division of Nanomaterials&Chemistry Hefei National Laboratory for Physical Sciences at the MicroscaleDepartment of ChemistryUniversity of Science and Technology of ChinaHefei 230026China

Electrocatalysis can enable efficient energy storage and conversion and thus is an effective way to achieve carbon neutrality.The unique structure and function of organisms can offer many ideas for the design of electrocatalysts,which has become one of the most promising research directions.Recently,the understanding of the mechanism of bio-inspired electrocatalysis has become clearer,which has promoted the design of bio-inspired catalysts and catalytic systems.Various bio-inspired catalysts(enzyme-like catalysts,layered porous catalysts,superhydrophobic/superhydrophilic surfaces,and so on)have been developed to enable efficient electrocatalytic reactions.Herein,we discuss the key advances in the field of bio-inspired electrocatalysts progressed in recent years.First,the role of bio-inspiration in increasing the intrinsic activity and number of active sites of catalysts is introduced.Then,the structure and mechanism of layered porous catalytic systems that mimic biological transport systems are comprehensively discussed.Subsequently,the design of three-phase interfaces from micro-nanoscale to atomic scale is highlighted,including the wettability of the electrode surface and the transport system near the electrode.We conclude the review by identifying challenges in bio-inspired electrocatalysts and providing insights into future prospects for the exciting research field.

关键词： bio-inspired electrocatalysts active sites layered porous structure three-phase interface

来源：

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

Synergistic effects and kinetics analysis for co-pyrolysis of vacuum residue and plastics

引用

Frontiers of Chemical Science and Engineering 2024年第5期18卷 71-81页

作者： Chao Wang Xiaogang Shi Aijun duan Xingying Lan Jinsen gao Qingang Xiong State Key Laboratory of Heavy Oil Processing China University of Petroleum-BeijingBeijing 102249China State Key Laboratory of Pulp and Paper Engineering South China University of TechnologyGuangzhou 510640China

This study utilizedathermogravimetric analyzer to assess the thermal decomposition behaviors and kinetics properties of vacuum residue(VR)and low-density polyethylene(LDPE)polymers.The kinetic parameters were calculated using the Friedman technique.To demonstrate the interactive effects between LDPE and VR during the co-pyrolysis process,the disparity in mass loss and mass loss rate between the experimental and calculated values was computed.The co-pyrolysis curves obtained through estimation and experimentation exhibited significantdeviations,whichwerei influencedby temperature and mixing ratio.A negative synergistic interaction was observed between LDPE and VR,although this inhibitory effect could be mitigated or eliminated by reducing the LDPE ratio in the mixture and increasing the co-pyrolysistemperature.Theco-pyrolysisprocess resulted in a reduction in carbon residue,which could be attributed to the interaction between LDPE and the heavy fractions,particularly resin and asphaltene,present in VR.These findings align with the pyrolysis behaviors exhibited by the four VR fractions.Furthermore,it was observed that the co-pyrolysis process exhibited lower activation energy as the VR ratio increased,indicating a continuous enhancement in the reactivity of the mixed samples during co-pyrolysis.

关键词： co-pyrolysis heavy residual oil polyethylene thermogravimetric analysis synergistic effects

来源：

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

Heuristic Expanding Disconnected Graph:A Rapid Path Planning Method for Mobile Robots

引用

Chinese Journal of Mechanical Engineering 2024年第2期37卷 68-82页

作者： Yong Tao Lian duan He gao Yufan Zhang Yian Song Tianmiao Wang School of Mechanical Engineering&Automation Beihang UniversityBeijing 100191China Aero-Engine Research Institute Beihang UniversityBeijing 102206China School of Large Aircraft Engineering Beihang UniversityBeijing 100191China

Existing mobile robots mostly use graph search algorithms for path planning,which suffer from relatively low planning efficiency owing to high redundancy and large computational complexity.Due to the limitations of the neighborhood search strategy,the robots could hardly obtain the most optimal global path.A global path planning algorithm,denoted as EDG*,is proposed by expanding nodes using a well-designed expanding disconnected graph operator(EDG)in this paper.Firstly,all obstacles are marked and their corners are located through the map pre-processing.Then,the EDG operator is designed to find points in non-obstruction areas to complete the rapid expansion of disconnected nodes.Finally,the EDG*heuristic iterative algorithm is proposed.It selects the candidate node through a specific valuation function and realizes the node expansion while avoiding collision with a minimum offset.Path planning experiments were conducted in a typical indoor environment and on the public dataset CSM.The result shows that the proposed EDG*reduced the planning time by more than 90%and total length of paths reduced by more than 4.6%.Compared to A*,Dijkstra and JPS,EDG*does not show an exponential explosion effect in map size.The EDG*showed better performance in terms of path smoothness,and collision avoidance.This shows that the EDG*algorithm proposed in this paper can improve the efficiency of path planning and enhance path quality.

关键词： Global path planning Mobile robot Expanding disconnected graph Edge node Offset

来源：

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

Responses of Nutrients to the Precipitation Variation and Land Use in Subtropical Monsoonal Small Mountainous Rivers:A Case Study of Baixi Watershed

引用

Journal of Ocean University of China 2024年第2期23卷 383-391页

作者： TIAN Yuan gao Fei CAO Ke LV Shenghua duan Xiaoyong YIN Ping Qingdao Institute of Marine Geology China Geological SurveyMinistry of Natural ResourcesQingdao 266237China Laboratory for Marine Geology Laoshan LaboratoryQingdao 266237China

Small mountainous rivers are characterized by large instantaneous fluxes and susceptible to extreme weather events,which can rapidly transport materials into the sea and have a significant impact on the ecological environment of estuaries and bays.In order to investigate the seasonal characteristics of nutrients in small mountainous rivers in the subtropical monsoon region and the output pattern to the sea during heavy precipitation,surveys on the mountainous rivers were carried out in Baixi watershed in August 2020(wet season),March 2021(dry season)and June 2021(Meiyu period).The results showed that the dissolved inorganic nitrogen(DIN)of the rivers has an average concentration of 752μg L^(−1)in the wet season and 1472μg L^(−1)in the dry season.The concentrations of dissolved inorganic phosphorus(DIP)in wet season and dry season were 63μg L^(−1)and 51μg L^(−1),respectively.Influenced by the changes of land use in sub-watersheds,DIN concentrations in the mainstream increased from 701μg L^(−1)in the upper reaches to 1284μg L^(−1)in the middle reaches.Two rainstorms during the Meiyu period in the watershed caused the pulse runoff in the river.The maximum daily runoff reached 70 times that before rains.The maximum daily fluxes of DIN and DIP were 109 and 247 times that before rains,respectively.In view that the watershed experienced several rainstorms in the wet season,the river,with pulse runoff,carries a large amount of nutrients into the sea in a short time,which will have a significant impact on the environment of Sanmen bay and its adjacent sea.

关键词： small mountainous river uneven precipitation rainstorm pulse runoff nitrogen and phosphorus

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Species’ geographical range, environmental range and traits lead to specimen collection preference of dominant plant species of grasslands in Northern China

引用

Plant Diversity 2024年第3期46卷 353-361页

作者： Jingya Zhang Cui Xiao Xiaoyu duan Xin gao Hao Zeng Rong'an Dong Gang Feng Keping Ma Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau&Inner Mongolia Key Laboratory of Grassland Ecology School of Ecology and EnvironmentInner Mongolia UniversityHohhot 010021China State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China

Many different factors,such as species traits,socio-economic factors,geographical and environmental factors,can lead to specimen collection preference.This study aims to determine whether grassland specimen collection in China is preferred by species traits(i.e.,plant height,flowering and fruiting period),environmental range(i.e.,the temperature and precipitation range)and geographical range(i.e.,distribution range and altitudinal range).Ordinary least squares models and phylogenetic generalized linear mixed models were used to analyze the relationships between specimen number and the explanatory variables.Random Forest models were then used to find the most parsimonious multivariate model.The results showed that interannual variation in specimen number between 1900 and 2020 was considerable.Specimen number of these species in southeast China was notably lower than that in northwest China.Environmental range and geographical range of species had significant positive correlations with specimen number.In addition,there were relatively weak but significant associations between specimen number and species trait(i.e.,plant height and flowering and fruiting period).Random Forest models indicated that distribution range was the most important variable,followed by flowering and fruiting period,and altitudinal range.These findings suggest that future floristic surveys should pay more attention to species with small geographical range,narrow environmental range,short plant height,and short flowering and fruiting period.The correction of specimen collection preference will also make the results of species distribution model,species evolution and other works based on specimen data more accurate.

关键词： Biological specimen Collection preference Dominant plant species Environmental range Geographical range Species traits

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Low-temperature NH_(3)-SCR performance of a novel Chlorella@Mn composite denitrification catalyst

引用

Journal of Environmental Sciences 2024年第3期137卷 271-286页

作者： Hengheng Liu Fengyu gao Songjin Ko Ning Luo Xiaolong Tang Erhong duan Honghong Yi Yuansong Zhou School of Energy and Environmental Engineering University of Science and Technology BeijingBeijing 100083China Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants Beijing 100083China School of Environmental Science and Engineering University of Science and Technology HebeiHebei 050018China Department of Chemistry Pyongyang University of ArchitecturePyongyangDemocratic People’s Republic of Korea

The synthesis process of conventional Mn-based denitrification catalysts is relatively complex and expensive.In this paper,a resource application of chlorella was proposed,and a Chlorella@Mn composite denitrification catalyst was innovatively synthesized by electrostatic interaction.The Chlorella@Mn composite denitrification catalyst prepared under the optimal conditions(0.54 g/L Mn^(2+)concentration,20 million chlorellas/mL concentration,450℃ calcination temperature)exhibited a well-developed pore structure and large specific surface area(122 m^(2)/g).Compared with MnOx alone,the Chlorella@Mn composite catalyst achieved superior performance,with~100%NH_(3)selective catalytic reduction(NH_(3)-SCR)denitrification activity at 100-225℃.The results of NH_(3)temperature-programmed desorption(NH_(3)-TPD)and H_(2)temperature-programmed reduction(H_(2)-TPR)showed that the catalyst had strong acid sites and good redox properties.Zeta potential testing showed that the electronegativity of the chlorella cell surface could be used to enrich with Mn^(2+).X-ray photoelectron spectroscopy(XPS)confirmed that Chlorella@Mn had a high content of Mn^(3+)and surface chemisorbed oxygen.In-situ diffuse refectance infrared Fourier transform spectroscopy(in-situ DRIFTS)experimental results showed that both Langmuir-Hinshelwood(L-H)and Eley-Rideal(E-R)mechanisms play a role in the denitrification process on the surface of the Chlorella@Mn catalyst,where the main intermediate nitrate species is monodentate nitrite.The presence of SO_(2)promoted the generation and strengthening of Bronsted acid sites,but also generated more sulfate species on the surface,thereby reducing the denitrification activity of the Chlorella@Mn catalyst.The Chlorella@Mn composite catalyst had the characteristics of short preparation time,simple process and low cost,making it promising for industrial application.

关键词： Chlorella@Mn catalyst NH_(3)-SCR Poisoning resistance Reaction mechanism Infuence of SO_(2)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Research on Anti-Fluctuation Control of Winding Tension System Based on Feedforward Compensation

引用

Computer Modeling in Engineering & Sciences 2024年第5期139卷 1239-1261页

作者： Yujie duan Jianguo Liang Jianglin Liu Haifeng gao Yinhui Li Jinzhu Zhang Xinyu Wen College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan030024China College of Electronic Information and Optical Engineering Taiyuan University of TechnologyTaiyuan030024China School of Electronic Information Engineering Taiyuan University of Science and TechnologyTaiyuan030000China

In the fiber winding process,strong disturbance,uncertainty,strong coupling,and fiber friction complicate the winding constant tension control.In order to effectively reduce the influence of these problems on the tension output,this paper proposed a tension fluctuation rejection strategy based on feedforward compensation.In addition to the bias harmonic curve of the unknown state,the tension fluctuation also contains the influence of bounded noise.A tension fluctuation observer(TFO)is designed to cancel the uncertain periodic signal,in which the frequency generator is used to estimate the critical parameter information.Then,the fluctuation signal is reconstructed by a third-order auxiliary filter.The estimated signal feedforward compensates for the actual tension fluctuation.Furthermore,a time-varying parameters fractional-order PID controller(TPFOPID)is realized to attenuate the bounded noise in the fluctuation.Finally,TPFOPID is enhanced by TFO and applied to control a tension control system considering multi-source disturbances.The stability of the method is analyzed by using the Lyapunov theorem.Finally,numerical simulations verify that the proposed scheme improves the tracking ability and robustness of the system in response to tension fluctuations.

关键词： Constant tension control anti-fluctuation strategy tension fluctuation observer time-varying parameters fractional-order PID controller feedforward compensate

来源：

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

Highly sensitive nanozyme strip:An effective tool for forensic material evidence identification

引用

Nano Research 2024年第3期17卷 1785-1791页

作者： Juanji Hong Zhanjun Guo Dihan duan Yi Zhang Xin Chen Yongjiu Li Zheng Tu Lei Feng Lei Chen Xiyun Yan Lizeng gao Minmin Liang Demin duan Experimental Center of Advanced Materials School of Materials Science&EngineeringBeijing Institute of TechnologyBeijing 100081China College of Bioscience and Biotechnology Shenyang Agricultural UniversityShenyang 110866China Chongqing kangjuquanhong biology science and technology Co. ltdChongqing 400026China Key Laboratory of Forensic Genetics Institute of Forensic ScienceMinistry of Public SecurityBeijing 100038China CAS Engineering Laboratory for Nanozyme Key Laboratory of BiomacromoleculesInstitute of BiophysicsChinese Academic of ScienceBeijing 100101China

During criminal case investigations,blood evidence tracing is critical for criminal investigation.However,the blood stains are often cleaned or covered up after the crime,resulting in trace residue and difficult tracking.Therefore,a highly sensitive and specific method for the rapid detection of human blood stains remains urgent.To solve this problem,we established a nanozyme-based strip for rapid detection of blood evidence with high sensitivity and specificity.To construct reliable nanozyme strips,we synthesized CoFe_(2)O_(4) nanozymes with high peroxidase-like activity by scaling up to gram level,which can be supplied for six million tests,and conjugated antibody as a detection probe in nanozyme strip.The developed CoFe_(2)O_(4) nanozyme strip can detect human hemoglobin(HGB)at a concentration as low as 1 ng/mL,which is 100 times lower than the commercially available colloidal gold strips(100 ng/mL).Moreover,this CoFe_(2)O_(4) nanozyme strip showed high generality on 12 substrates and high specificity to human HGB among 13 animal blood samples.Finally,we applied the developed CoFe_(2)O_(4) nanozyme strip to successfully detect blood stains in three real cases,where the current commercial colloidal gold strip failed to do.The results suggest that the CoFe_(2)O_(4) nanozyme strip can be used as an effective on-scene detection method for human blood stains,and can further be used as a long-term preserved material evidence for traceability inquiry.

关键词： CoFe_(2)O_(4)nanozyme nanozyme strip peroxidase-like activity human hemoglobin blood evidence

来源：

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

Nickel-catalyzed carbonylative four-component 1,4-dicarbofunctionalization of 1,3-enynes

引用

Science China Chemistry 2024年第6期67卷 2029-2038页

作者： Yan Zhao Qi-Chao Shan Hong Xin Pin gao Xu Yang Xin-Hua duan Li-Na Guo Department of Chemistry School of ChemistryXi’an Key Laboratory of Sustainable Energy Material Chemistry and Engineering Research Center of Energy StorageMaterials and DevicesMinistry of EducationXi’an Jiaotong UniversityXi’an710049China School of Electrical Engineering Xi’an Jiaotong UniversityXi’an710049China

An efficient Ni-catalyzed four-component 1,4-carbocarbonylation of 1,3-enynes with activated alkyl halides and arylboronic acids under atmospheric pressure of CO is presented.By tuning the electronic and steric effects of alkyl radicals,both electronrich and electron-deficient 1,3-enynes were compatible with this cascade.This protocol features mild conditions,broad substrate scope,excellent functional group compatibility and facile gram-scale synthesis,providing a practical approach to the quaternary carbon center-containing allenyl ketones.Mechanistic study revealed that the acyl-NiIIspecies plays an important role in both the coupling and the alkyl radical generation processes.

关键词： Ni catalysis four-component 1 4-carbocarbonylation 1 3-enynes

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：