检索结果-南通市图书馆

Heisenberg Group and Energy-Momentum Conservative Law in de-Sitter Spaces—— In Memory of the 100th Anniversary of Einstein＇s Special Relativity and the 70th Anniversary of Dirac＇s de-Sitter Spaces

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2005年第3X期44卷 389-392页

作者： lu qi-keng Institute of Mathematics Academy of Mathematics and System Sciences the Chinese Academy of Sciences Beijing 100080 China

In 1935 Dirac established the physical wave equations in the de-Sitter spaces but neither energy-momentum operators nor their conservative laws were given. In this article it is proved that in the de-Sitter group there is a subgroup group isomorphic to the Heisenberg group and the generators of this groups are the energy-momentum operators which obey a conservative law.

关键词： energy-momentum conservation Heisenberg grup de-Sitter space

Poisson kernel and Cauchy formula of a non-symmetric transitive domain

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2010年第7期53卷 1678-1683页

作者： lu qi-keng Institute of Mathematics, Academy of Mathematics and System Science, Chinese Academy of Sciences, Beijing 100190, China Institute of Mathematics Academy of Mathematics and System Science Chinese Academy of Sciences Beijing China

In 1965, lu Yu-qian discovered that the Poisson kernel of the homogenous domain S m,p,q={Z∈Cm×m, Z1∈Cm×p,Z2 ∈Cq×m|2i1( Z-Z+)-Z1Z1′-Z2′Z2>0} does not satisfy the Laplace-Beltrami equation associated with the Bergman metric when S m,p,q is not symmetric. However the map T0:Z→Z, Z1→Z1 , Z2→Z2 transforms S m,p,q into a domain S I (m, m + p + q) which can be mapped by the Cayley transformation into the classical domains R I (m, m + p + q). The pull back of the Bergman metric of R I (m, m + p + q) to S m,p,q is a Riemann metric ds 2 which is not a Khler metric and even not a Hermitian metric in general. It is proved that the Laplace-Beltrami operator associated with the metric ds 2 when it acts on the Poisson kernel of S m,p,q equals 0. Consequently, the Cauchy formula of S m,p,q can be obtained from the Poisson formula.

关键词： Poisson kernel Cauchy formula

Interface compatibility between sulfide solid electrolytes and Ni-rich oxide cathode materials:Factors,modification,perspectives

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2025年第2期101卷 233-262页

作者： Tianwen Yang Haijuan Pei Haijian Lv Shijie lu qi Liu Daobin Mu Beijing Key Laboratory of Environmental Science and Engineering School of Materials Science an Engineering Beijing Institute of Technology State Key Laboratory of Space Power-Sources Technology Shanghai Institute of Space Power-Sources

All-solid-state batteries(ASSBs) assembled with sulfide solid electrolytes(SSEs) and nickel(Ni)-rich oxide cathode materials are expected to achieve high energy density and safety,representing potential candidates for the next-generation energy storage ***,interfacial issues between SSEs and Nirich oxide cathode materials,attributed to space charge layer,interfacial side reactions,and mechanical contact failure,significantly restrict the performances of *** interface degradation is closely related to the components of the composite cathode and the process of electrode *** on the influencing factors of interface compatibility between SSEs and Ni-rich oxide cathode,this article systematically discusses how cathode active materials(CAMs),electrolytes,conductive additives,binders,and electrode fabrication impact the interface *** addition,the strategies for the compatibility modification are ***,the challenges and prospects of intensive research on the degradation and modification of the SSE/Ni-rich cathode material interface are *** review is intended to inspire the development of high-energy-density and high-safety all-solid-state batteries.

关键词： All–solid–state batteries Influencing factors Interface compatibility Ni–rich oxide cathode Sulfide solid electrolyte

The effect of fine grits and fine debris concentrations on the MLVSS/MLSS ratio of an activated sludge system

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2025年第1期147卷 607-616页

作者： Zhao Jiang Zhiheng Xia Shuai Liu qiWei Haitao Fan lu qi Guohua Liu Hongchen Wang Low-carbon Water Environment Technology Research Center School of Environment&Natural ResourcesRenmin University of ChinaBeijing 100872China

This study embarks on an explorative investigation into the effects of typical concentrations and varying particle sizes of fine grits(FG,the involatile portion of suspended solids)and fine debris(FD,the volatile yet unbiodegradable fraction of suspended solids)within the influent on themixed liquor volatile suspended solids(MLVSS)/mixed liquor suspended solids(MLSS)ratio of an activated sludge *** meticulous experimentation,it was discerned that the addition of FG or FD,the particle size of FG,and the concentration of FD bore no substantial impact on the pollutant removal efficiency(denoted by the removal rate of COD and ammonia nitrogen)under constant operational ***,a notable decrease in the MLVSS/MLSS ratio was observed with a typical FG concentration of 20 mg/L,with smaller FG particle sizes exacerbating this ***,variations in FD concentrations influenced both MLSS andMLVSS/MLSS ratios;a higher FD concentration led to an increased MLSS and a reduced MLVSS/MLSS ratio,indicating FD accumulation in the system.A predictive model for MLVSS/MLSS was constructed based on quality balance calculations,offering a tool for foreseeing the MLVSS/MLSS ratio under stable long-term influent conditions of FG and *** model,validated using data from the BXH wastewater treatment plant(WWTP),showcased remarkable accuracy.

关键词： Fine grits and fine debris Activated sludge system MLVSS/MLSS ratio Predictive model

Spatiotemporal characteristics and influencing factors of vegetation water use efficiency on the Tibetan Plateau in 2001–2020

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

Journal of Geographical Sciences 2025年第1期35卷 39-64页

作者： HE Chenyang WANG Yanjiao YAN Feng lu qi School of Ecological and Environmental Science East China Normal UniversityShanghai200241China Institute of Ecological Conservation and Restoration Chinese Academy of ForestryBeijing100091China National Climate Center China Meteorological AdministrationBeijing100081China

Water use efficiency(WUE),as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ***,in the context of global warming,WUE evolution and its primary drivers on the Tibetan Plateau remain *** study employed the ensemble empirical mode decomposition method and the random forest algorithm to decipher the nonlinear trends and drivers of WUE on the Tibetan Plateau in 2001–*** indicated an annual mean WUE of 0.8088 gC/mm·m^(2)across the plateau,with a spatial gradient reflecting decrease from the southeast toward the *** manifesting monotonous trends of increase or decrease in WUE accounted for 23.64%and 9.69%of the total,***,66.67%of the region exhibited trend reversals,i.e.,39.94%of the area of the Tibetan Plateau showed transition from a trend of increase to a trend of decrease,and 26.73%of the area demonstrated a shift from a trend of decrease to a trend of *** factors accounted for 70.79%of the variability in *** leaf area index and temperature served as the major driving forces of WUE variation.

关键词： water use efficiency spatiotemporal characteristic influencing factor Tibetan Plateau

CO_(2)-mediated bicarbonate conversion to concentrated formate in a CEM-based electrolyzer

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2025年第1期100卷 605-611页

作者： Haocheng Xiong Donghuan Wu Haonan Li Andrew Li qikun Hu Siyao Song Bingjun Xu qi lu State Key Laboratory of Chemical Engineering Department of Chemical EngineeringTsinghua UniversityBeijing 100084China College of Chemistry and Molecular Engineering Peking UniversityBeijing 100871China Ordos Laboratory Inner Mongolia 017000China

Renewable energy-driven bicarbonate conversion to valuable chemicals presents an attractive strategy for mitigating CO_(2)emissions,as bicarbonate can be efficiently generated from the capture of atmospheric CO_(2)using alkaline solutions with reactive *** this work,we present a CO_(2)-mediated bicarbonate conversion to pure formate using a cation exchange membrane-based electrolyzer with a 25 cm^(2)electrode *** electrolysis achieved selectivities exceeding 75%for formate at a total current of 2.5 A,achieving formate concentrations up to 1.2 M and yields as high as 95%over extended *** techno-economic assessment confirmed the economic viability of the process,highlighting the potential for bicarbonate electrolysis as a sustainable method for producing valuable chemicals.

关键词： Electrocatalysis Techno-economic assessments Electrochemistry Flow electrolyzer

Distribution and mapping of temperate savanna in the sandy lands of eastern China

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2025年第1期68卷 128-141页

作者： Xiaoya LI Feng WANG Tao DUAN Kaijie YANG Bin YANG Chunmei WANG Xin TIAN qi lu Institute of Ecological Conservation and Restoration Institute of Desertification StudiesChinese Academy of ForestryBeijing100091China Institute of Desertification Institute of Desertification StudiesChinese Academy of ForestryBeijing100091China Institute of Great Green Wall Bayan Nur015200China Satellite Application Centre for Ecology and Environment MEEBeijing100094China Institute of Microelectronics Chinese Academy of SciencesBeijing100029China Aerospace Information Research Institute Chinese Academy of SciencesBeijing100094China Institute of Forest Resource Information Techniques Chinese Academy of ForestryBeijing100091China

Savannas are distributed globally across various *** perform a significant socioeconomic role in regulating net primary productivity and the terrestrial carbon *** to the high spatial heterogeneity induced by the mixed distribution of trees and grasses,current global land-cover classification maps often classify savannas as forests or grasslands Temperate savannas in China cover a vast area,yet their spatial patterns and extent remain poorly *** study developed a novel remote sensing temperate savannas mapping method by integrating very high-resolution(VHR)unmanned aerial vehicle(UAV)and GF-6 satellite imagery based on the vegetation structure characteristics of temperate savannas using the FAO definition of *** and validation datasets were collected from VHR UAV imagery covering the main temperate savannah types with a ground area of 1818 *** fractional woody vegetation cover(FWVC)and fractional herbaceous vegetation cover(FHVC)in temperate savannas were estimated by integrating Classification and Regression Tree and Random Forest *** current distribution of temperate savannas in the Horqin and Otindag Sandy Lands of Eastern China was mapped to a unit area of 0.5 *** root-mean-square error(RMSE)values for the FWVC and FHVC models were 10.69%and 11.67%,and the R^(2)values were 0.66 and 0.63,*** assessment indicated that the new temperate savanna map had high identification accuracy,with a Kappa coefficient of 0.70,overall accuracy of 0.88,and average accuracy of *** savannas in the sandy lands of eastern China were primarily distributed in the northern Horqin Sandy Land the central and eastern regions of the Otindag Sandy Land,and the transition zone from the southern slopes of the Greater Khingan Mountains to the plains,covering a total area of 3.27×10^(6)*** main savannah types were elm,oak/maple,and shrub *** savannas were widely distributed in the Otindag Sandy Land a

关键词： Temperate savanna UAV imagery GF-6 Fractional woody vegetation cover Fractional herbaceous vegetation cover Machine learning

同方期刊数据库

Support effect and confinement effect of porous carbon loaded tin dioxide nanoparticles in high-performance CO_(2) electroreduction towards formate

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2025年第1期36卷 597-602页

作者： Xingxing Jiang Yuxin Zhao Yan Kong Jianju Sun Shangzhao Feng Xin lu qi Hu Hengpan Yang Chuanxin He College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen 518060China

Leveraging the interplay between the metal component and the supporting material represents a cornerstone strategy for augmenting electrocatalytic efficiency,e.g.,electrocatalytic CO_(2)reduction reaction(CO_(2)RR).Herein,we employ freestanding porous carbon fibers(PCNF)as an efficacious and stable support for the uniformly distributed SnO_(2)nanoparticles(SnO_(2)PCNF),thereby capitalizing on the synergistic support effect that arises from their strong *** one hand,the interaction between the SnO_(2)nanoparticles and the carbon support optimizes the electronic configuration of the active *** interaction leads to a noteworthy shift of the d-band center toward stronger intermediate adsorption energy,consequently lowering the energy barrier associated with CO_(2)*** a result,the Sn O_(2)PCNF realizes a remarkable CO_(2)RR performance with excellent selectivity towards formate(98.1%).On the other hand,the porous carbon fibers enable the uniform and stable dispersion of SnO_(2)nanoparticles,and this superior porous structure of carbon supports can also facilitate the exposure of the SnO_(2)nanoparticles on the reaction interface to a great ***,adequate contact between active sites,reactants,and electrolytes can significantly increase the metal utilization,eventually bringing forth a remarkable7.09 A/mg mass *** work might provide a useful idea for improving the utilization rate of metals in numerous electrocatalytic reactions.

关键词： CO_(2)electroreduction Support effect Porous carbon fiber Formate Mass activity

A nitrogen-rich halogen-bonded organic framework (XOF) for efficient iodine capture and security printing

在线全文

学校读者我要写书评

暂无评论

SCIENCE CHINA-CHEMISTRY 2025年第2期68卷 631-640页

作者： Zhao, qi Sun, Penghao Gong, Guanfei Chen, Yi luo, Lingzhi Yin, Yongfei Li, Chunsheng Wang, Jike Wang, lu Chen, Shigui Wuhan Univ Inst Adv Studies Wuhan 430072 Peoples R China Ningxia Vocat Tech Coll Ind & Commerce Yinchuan 750100 Peoples R China Suzhou Univ Sci & Technol Sch Chem & Life Sci Key Lab Adv Electrode Mat Novel Solar Cells Petr & Suzhou 215009 Peoples R China

The escalating utilization of nuclear energy and nuclear medicine raises concerns about the environmental impact of radioactive iodine, necessitating the development of effective iodine adsorbents, especially under a real-world scenario with extremely low iodine concentration and elevated temperature. Herein, we have presented the construction of a nitrogen-abundant two-dimensional (2D) halogen-bonded organic framework, XOF-TNP, characterized by exceptional crystallinity, thermal stability, and nitrogen-rich structures. XOF-TNP exhibits strong binding to iodine, thanks to the fact that iodine can be pre-enriched into the framework through N & ctdot;I interactions. The nitrogen-rich framework and I+ synergistically have extremely high binding force to iodine, enabling the rapid and efficient capture of iodine in both vapor and solution phases, with significant recyclability. Further flow-through adsorption experiments using an XOF-TNP-packed column achieve 99% iodine removal from hexane and aqueous solutions, surpassing traditional activated carbon. This highlights its potential for environmental remediation. XOF-TNP enables the development of a novel rewritable security paper, utilizing its iodine adsorption properties to encrypt and decrypt QR codes. This research expands the application scope of halogen-bonded organic frameworks, providing insights into the design of materials for environmental remediation and security applications.

关键词： [N & ctdot I+& ctdot N] halogen bond halogen-bonded organic framework iodine capture security printing supramolecular assembly