检索结果-南通市图书馆

Space-Time Properties as Quantum Effects. Restrictions Imposed by Grothendieck’s Scheme Theory

Journal of Modern Physics 2019年第7期10卷 795-823页

作者： leonid lutsev Ioffe Physical-Technical Institute Russian Academy of Sciences St. Petersburg Russia

In this paper we consider properties of the four-dimensional space-time manifold M caused by the proposition that, according to the scheme theory, the manifold M is locally isomorphic to the spectrum of the algebra A, M ≅Spec (A), where A is the commutative algebra of distributions of quantum-field densities. Points of the manifold M are defined as maximal ideals of density distributions. In order to determine the algebra A, it is necessary to define multiplication on densities and to eliminate those densities, which cannot be multiplied. This leads to essential restrictions imposed on densities and on space-time properties. It is found that the only possible case, when the commutative algebra A exists, is the case, when the quantum fields are in the space-time manifold M with the structure group SO (3, 1) (Lorentz group). The algebra A consists of distributions of densities with singularities in the closed future light cone subset. On account of the local isomorphism M ≅Spec (A) , the quantum fields exist only in the space-time manifold with the one-dimensional arrow of time. In the fermion sector the restrictions caused by the possibility to define the multiplication on the densities of spinor fields can explain the chirality violation. It is found that for bosons in the Higgs sector the charge conjugation symmetry violation on the densities of states can be observed. This symmetry violation can explain the matter-antimatter imbalance. It is found that in theoretical models with non-abelian gauge fields instanton distributions are impossible and tunneling effects between different topological vacua | n> do not occur. Diagram expansion with respect to the -algebra variables is considered.

关键词： Space-Time Properties Quantum Field Arrow of Time Chirality Algebra of Distributions Symmetry Violation

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

A new method for precise optical measurements of the sub-micron height of levitation of droplet clusters

引用

Particuology 2024年第4期87卷 173-178页

作者： Alexander A.Fedorets Eduard E.Kolmakov leonid A.Dombrovsky University of Tyumen 6 Volodarskogo StTyumen625003Russia Engineering Faculty Ariel UniversityP0.B.3407000ArielIsrael Joint Institute for High Temperatures 17A Krasnokazarmennaya StMoscow111116Russia

Droplet clusters levitating over the locally heated water surface are considered a very promising phe-nomenon of microfluidics for the potential use of the droplets as unique microreactors for microbio-logical experiments.A new optical method is suggested for precise measurements of the sub-micron levitation height of single *** method is based on the analysis of variable colors of the inter-ference halo around the *** the first time,it is possible to measure the extremely low downward velocity of droplets,which grow due to steam *** velocity was found to be 5-8 nm/*** height of the levitation of various droplets just before their coalescence with a layer of water was also *** measurements might be used for the verification of sophisticated models for the droplet levitation to be developed for a very thin layer of humid air under the droplet when the Knudsen effect should be taken into account.

关键词： Precise measurements Interferometric method Droplet cluster Levitation height

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

Centroid Hom-associative Algebras and Centroid Hom-Lie Algebras

引用

Acta Mathematica Sinica,English Series 2024年第4期40卷 935-961页

作者： Yu Xiu BAI leonid A.BOKUT Yu Qun CHEN Ze Rui ZHANG Department of Mathematics Teaching Guangzhou Civil Aviation CollegeGuangzhou 510403P.R.China Sobolev Institute of Mathematics Novosibirsk 630090Russia Novosibirsk State University Novosibirsk 630090Russia School of Mathematical Sciences South China Normal UniversityGuangzhou 510631P.R.China

In this article,we construct free centroid hom-associative algebras and free centroid hom-Lie *** also construct some other relatively free centroid hom-associative algebras by applying the Gr?bner-Shirshov basis theory for(unital)centroid hom-associative ***,we prove that the"Poincaré-Birkhoff-Witt theorem"holds for certain type of centroid hom-Lie algebras over a field of characteristic 0,namely,every centroid hom-Lie algebra such that the eigenvectors of the mapβlinearly generates the whole algebra can be embedded into its universal enveloping centroid hom-associative algebra,and the linear basis of the universal enveloping algebra does not depend on the multiplication table of the centroid hom-Lie algebra under consideration.

关键词： Centroid hom-Lie algebra centroid hom-associative algebra Gr?bner-Shirshov basis

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

A simple modification to the classical SIR model to estimate the proportion of under-reported infections using case studies in flu and COVID-19

引用

Infectious Disease Modelling 2024年第4期9卷 1147-1162页

作者： leonid Kalachev Jon Graham Erin L.Landguth Mathematical Sciences University of MontanaMissoulaUSA Center for Population Health Research School of Public and Community Health SciencesUniversity of MontanaMissoulaUSA

Background:Under-reporting and,thus,uncertainty around the true incidence of health events is common in all public health reporting *** the problem of underreporting is acknowledged in epidemiology,the guidance and methods available for assessing and correcting the resulting bias are ***:We aim to design a simple modification to the Susceptible e Infected e Removed(SIR)model for estimating the fraction or proportion of reported infection ***:The suggested modification involves rescaling of the classical SIR model producing its mathematically equivalent version with explicit dependence on the reporting parameter(true proportion of cases reported).We justify the rescaling using the phase plane analysis of the SIR model system and show how this rescaling parameter can be estimated from the data along with the other model ***:We demonstrate how the proposed method is cross-validated using simulated data with known disease cases and then apply it to two empirical reported data sets to estimate the fraction of reported cases in Missoula County,Montana,USA,using:(1)flu data for 2016e2017 and(2)COVID-19 data for fall of ***:We establish with the simulated and COVID-19 data that when most of the disease cases are presumed reported,the value of the additional reporting parameter in the modified SIR model is close or equal to one,so that the original SIR model is appropriate for data ***,the flu example shows that when the reporting parameter is close to zero,the original SIR model is not accurately estimating the usual rate parameters,and the re-scaled SIR model should be *** research demonstrates the role of under-reporting of disease data and the importance of accounting for underreporting when modeling simulated,endemic,and pandemic disease *** reporting the“true”number of disease cases will have downstream impacts on predictions of disease dynamics.A simple parameter adjustment

关键词： Modeling of epidemics SIR type models flu and COVID-19 Under-reporting parameter Proportion of reported disease cases

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

A systematic review of cytoreductive prostatectomy outcomes and complications in oligometastatic disease

引用

Asian Journal of Urology 2024年第2期11卷 208-220页

作者： Andrey Morozov leonid Chuvalov Mark Taratkin Mikhail Enikeev leonid Rapoport Nirmish Singla Eric Barret Elena Poddubskaya Maria Borodina Georg Salomon Juan Gomez Rivas Dmitry Enikeev Institute for Urology and Reproductive Health Sechenov UniversityMoscowRussia Young Academic Urologists EAUthe Netherlands Department of Urology James Buchanan Brady Urological InstituteThe Johns Hopkins University School of MedicineBaltimoreUSA Department of Urology Institut Mutualiste MontsourisParisFrance Sechenov University MoscowRussia Hertsen Moscow Oncology Research InstituteMoscowRussia Hertsen Moscow Oncology Research Institute MoscowRussia Martini Clinic University Medical Center Hamburg-EppendorfHamburgGermany Department of Urology Clinico San Carlos University HospitalMadridSpain Department of Urology Medical University of ViennaViennaAustria

Objective: To analyze outcomes and complications of cytoreductive prostatectomy (CRP) for oligometastatic prostate cancer (PCa) in order to elucidate its role in this ***: We performed a systematic literature search using three databases (Medline, Scopus, and Web of Science). The primary endpoints were oncologic outcomes. The secondary endpoints were complication rates and functional ***: In all studies, overall survival was better or at least comparable variable in the groups with CRP compared to no local treatment. The greatest benefit from CRP in 5-year overall survival in one study was 67.4% for CRP versus 22.5% for no local treatment. Cancer-specific survival (CSS) showed the same trend. Several authors found significant benefits from CSS in the CRP group: from 79% vs. 46% to 100% vs. 61%. CRP was a predictor of better CSS (hazard ratio 0.264, p=0.004). Positive surgical margin rates differed widely from 28.6% to 100.0%. Urinary continence in CRP versus RP for localized PCa was significantly lower (57.4% vs. 90.8%, p<0.0001). Severe incontinence occurred seldom (2.5%-18.6%). Total complication rates after CRP differed widely, from 7.0% to 43.6%. Rates of grades 1 and 2 events prevailed. Patients on ADT alone also showed a considerable number of complications varying from 5.9% to 57.7%.Conclusion: CRP improves medium-term cancer control in patients with oligometastatic PCa. The morbidity and complication rates of this surgery are comparable with other approaches, but postoperative incontinence rate is higher compared with RP for localized disease.

关键词： Systematicreview Prostatecancer Oligometastatic Bone metastases Cytoreductive prostatectomy

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

A Review on the Influence of In-cylinder Turbulence Type on Combustion Characteristics of High Power-Density Diesel Engine

引用

Journal of Traffic and Transportation Engineering(English Edition) 2024年

作者： Zhongxi Tong Han Wu Zhicheng Shi leonid Myagkov School of Mechanical Engineering， Beijing Institute of Technology Department of Piston Engines， Bauman Moscow State Technical University

With the continuous improvement of performance requirements， direct injection diesel engines have gradually developed towards more small， lightweight， and high power， named as high power-density. It needs more injected fuel can be mixed and burn at the same duration time to guarantee the thermal-power conversion effects. It is required that the combustion system has a fast mixing speed of fuel and gas， and a fast combustion speed. Organizing appropriate cylinder turbulence is an effective means of optimizing combustion to reach requirements. The current work is aim to investigates and summarizes the influence of different types of in cylinder turbulence coursed by intake， spray， and combustion chamber configuration on the performance of a highly intensified diesel engine from the three causes of turbulence. The comparative study found that the adoption of a separate combustion chamber， the increase of intake swirl and number of nozzles can have positive effect on the optimization of the combustion process of a highly intensified diesel engine， but for different combustion chamber types， the influence of intake swirl and spray parameters was different. The separated combustion chamber is more sensitive to spray parameters than the combustion chamber without wall guide design. Compared with the transverse separated combustion chamber， the longitudinal separated combustion chamber is more suitable for large intake swirl ratio. For a specific combustion chamber structure， both intake swirl and spray parameters have optimal values.

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Pulsed THz radiation under ultrafast optical discharge of vacuum photodiode

引用

Frontiers of Optoelectronics 2024年第2期17卷 99-112页

作者： Aleksandr Ushakov Kseniia Mamaeva leonid Seleznev Georgy Rizaev Vladimir Bukin Timophey Dolmatov Pavel Chizhov Vladimir Bagdasarov Sergey Garnov Prokhorov General Physics Institute of the Russian Academy of Sciences Moscow 119991Russia Physical Institute Russian Academy of SciencesMoscow 119991Russia Moscow Institute of Physics and Technology Dolgoprudny 141700Russia Russian Institute for Scientific and Technical Information Moscow 125190Russia

In this paper,we first present an experimental demonstration of terahertz radiation pulse generation with energy up to 5 pJ under the electron emission during ultrafast optical discharge of a vacuum *** use a femtosecond optical excitation of metallic copper photocathode for the generation of ultrashort electron bunch and up to 45 kV/cm external electric field for the photo-emitted electron *** of terahertz pulses energy as a function of emitted charge density,incidence angle of optical radiation and applied electric field have been *** and polarization characteristics of generated terahertz pulses have also been *** proposed semi-analytical model and simulations in COMSOL Multiphysics prove the experimental data and allow for the optimization of experimental conditions aimed at flexible control of radiation parameters.

关键词： Electron emission Vacuum photodiode Ultrafast excitation Terahertz

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

Electrogenic sulfur oxidation mediated by cable bacteria and its ecological effects

引用

Environmental Science and Ecotechnology 2024年第4期20卷 34-41页

作者： Zhenyu Wang leonid Digel Yongqiang Yuan Hui Lu Yonggang Yang Carsten Vogt Hans-Hermann Richnow Lars Peter Nielsen Department of Isotope Biogeochemistry Helmholtz Centre for Environmental Research e UFZPermoserstraße 1504318LeipzigGermany Center for Electromicrobiology Department of BiologyAarhus UniversityDK-8000AarhusDenmark Key Laboratory of Karst Georesources and Environment Ministry of EducationCollege of Resources and Environmental EngineeringGuizhou UniversityGuiyang550025China School of Environmental Science and Engineering Sun Yat-Sen UniversityGuangzhou510006China School of Life Science and Engineering Foshan UniversityFoshan528225China State Key Laboratory of Applied Microbiology Southern China Institute of MicrobiologyGuangdong Academy of SciencesGuangzhou510007China

At the sediment-water interfaces,filamentous cable bacteria transport electrons from sulfide oxidation along their filaments towards oxygen or nitrate as electron *** multicellular bacteria belonging to the family Desulfobulbaceae thus form a biogeobattery that mediates redox processes between multiple *** bacteria were first reported in *** the past years,cable bacteria have been found to be widely distributed across the *** potential in shaping the surface water environments has been extensively studied but is not fully *** this review,the biogeochemical characteristics,conduction mechanisms,and geographical distribution of cable bacteria,as well as their ecological effects,are systematically reviewed and *** insights for understanding and applying the role of cable bacteria in aquatic ecology are summarized.

关键词： Cable bacteria Electrogenic sulfur oxidation Long-distance electron transfer Aquatic ecology

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

Spherically Symmetric Problem of General Relativity for a Fluid Sphere

引用

Journal of Modern Physics 2024年第4期15卷 401-415页

作者： Valery V. Vasiliev leonid V. Fedorov Institute of Applied Mechanics of Russian Academy of Sciences Moscow Russia

The paper is devoted to a spherically symmetric problem of General Relativity (GR) for a fluid sphere. The problem is solved within the framework of a special geometry of the Riemannian space induced by gravitation. According to this geometry, the four-dimensional Riemannian space is assumed to be Euclidean with respect to the space coordinates and Riemannian with respect to the time coordinate. Such interpretation of the Riemannian space allows us to obtain complete set of GR equations for the external empty space and the internal spaces for incompressible and compressible perfect fluids. The obtained analytical solution for an incompressible fluid is compared with the Schwarzchild solution. For a sphere consisting of compressible fluid or gas, a numerical solution is presented and discussed.

关键词： General Relativity Spherically Symmetric Problem Fluid Sphere

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

铁镁电气石Y位阳离子主导的构效关系

引用

硅酸盐学报 2024年第10期52卷 3192-3204页

作者：周琳张伟周磊郭铭董发勤 Kotova Elena leonidovna Kotov leonid Nafanailovichd 西南科技大学固体废物处理与资源化教育部重点实验室四川绵阳621010中国西南科技大学分析测试中心四川绵阳621010中国西南科技大学核废物与环境安全国防重点学科实验室四川绵阳621000中国西南科技大学环境与资源学院四川绵阳621010中国 Mining Museum St.Petersburg Mining UniversitySt Petersburg 199106Russia Department of Radiophysics and Electronics Syktyvkar State UniversitySyktyvkar 167001Russia

具有特异性对称结构的天然自发极化矿物—电气石被广泛应用于环保和医疗保健领域,厘清电气石成分-结构-性能之间的作用关系可为电气石行业提供性能最优的理想构型,为其他天然复杂矿物的构效分析和性能调控提供方法参考。通过对含铁电气... 详细信息

具有特异性对称结构的天然自发极化矿物—电气石被广泛应用于环保和医疗保健领域,厘清电气石成分-结构-性能之间的作用关系可为电气石行业提供性能最优的理想构型,为其他天然复杂矿物的构效分析和性能调控提供方法参考。通过对含铁电气石样品进行全成分、端元占位、晶体微结构和自发极化性能分析,揭示了铁镁电气石成分-微结构-自发极化性能的影响控制过程:在铁含量高于镁含量的电气石中,晶胞体积随镁含量升高而升高,Fe^(2+)含量越高且Z位含铁时,电气石多面体扭曲增强,固有电偶极矩增大;在铁含量低于镁含量的电气石中,晶胞体积随铁含量升高而增大,结构扭曲和固有电偶极矩随铁含量的升高而减弱,随Fe^(2+)含量增大而增大;自发极化性测试证明电气石的性能强弱与固有电偶极矩变化规律一致;整理过往文献数据,分析Y位阳离子主导下的电气石固有电偶极矩变化趋势,揭示以Fe元素为主要影响因素的构效关系:当Mg/Fe摩尔比小于1时,电气石性能随Fe含量的减小而减弱;当Mg/Fe摩尔比大于1时,电气石的性能随Fe含量减小而增强;而当Mg/Fe摩尔比大于2时,其自发极化性上升趋势则趋于平稳。

关键词：铁镁电气石 Y位阳离子自发极化性构效关系

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：