检索结果-南通市图书馆

NUMERICAL SIMULATION OF VISCOUS FLOW AROUND AN APPENDED SUBMARINE MODEL

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 1997年第2期9卷 58-64页

作者： zhao, feng China Ship Scientific Research Cent Wuxi China

A multizone/multiblock coupled RANS equation solver is presented to numerically simulate the viscous flow around an appended submarine model at Reynolds number 1. E7. k-ε two equation turbulenc model together with wall function are used. The resulting finite difference equations are solved by SIMPLEC, ADI. The technique of rising up the bottom surface is presented to overcome radial contraction problem in Cartesian coordinate system. Benchmark numerical calculations have been compared with experimental data, the radial distribution of axial velocity on the propeller disk plane is 4. 63%.

关键词： appened submarine model multiblock coupled solver technique of rising up the bottom surface

Some new thoughts of definitions of terms of sedimentary facies:Based on Miall's paper(1985)

在线全文

学校读者我要写书评

暂无评论

Journal of Palaeogeography 2022年第1期11卷 1-7页

作者： Zeng-zhao feng China University of Petroleum(Beijing) Beijing100083China

In recent years,the Journal of Palaeogeography(Chinese Edition and English Edition)continually received manuscripts,in which some authors are from China and some are from Pakistan,Lithuania,Morocco,South Africa,*** authors of these manuscripts,according to the viewpoint and method of Miall’s paper(1985),selected rocks from each bed in the clastic sections of their study areas and induced some rock types,such as conglomerates,sandstones and fine-grained stones,and considered them as *** does not conform to the definition of lithofacies.I wrote some papers,i.e.,feng(2018,2019,2020),to point out the problems and hope that the authors worldwide,especially Chinese authors,will not continually cite,spread and follow Miall’s paper(1985)viewpoint and method *** is the first person who considered rocks(in fact,the sediments)as lithofacies and proposed a facies analysis *** viewpoint and facies analysis method confused the definition of facies and facies analysis *** current paper is a special article to discuss the principal problems of Miall’s paper(1985),i.e.,he considered the sediments as lithofacies and utilized lithofacies to analyze facies,but not to discuss the contributions and less strictness of architectural elements of his ***,I have to declare that the facies in my current paper is the facies of sedimentary petrology,but not of other geological disciplines,such as igneous petrology,metamorphic petrology,palaeontology,stratigraphy,geophysics,***,the definitions of facies and lithofacies are *** current paper will adhere to the policy of“A hundred flowers blossom and a hundred schools of thought contend”.I hope that through academic discussions,contends and geological practice,these problems will be solved gradually.

关键词： Rocks Sediments Sedimentary environments Facies Sedimentary facies Lithofacies Lithology Facies analysis method A hundred flowers blossom and a hundred schools of thought contend Geological practice

Deoxygenative alkylation of tertiary amides using alkyl iodides under visible light

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2022年第11期65卷 2231-2237页

作者： feng zhao feng Jiang Xiaoming Wang The Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials College of Chemistry and Materials ScienceShanghai Normal UniversityShanghai 200234China State Key Laboratory of Organometallic Chemistry Center for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China School of Chemistry and Materials Science Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou310024China

It is an unceasing goal for organic chemists to develop new catalytic methodologies for functional group transformations of widespread molecular structures. Amides are readily available from simple and reliable reactions, which are common structural units found in biologically active compounds. Consequently, they are attractive to be exploited in amine synthesis by reductive cross coupling. However, deoxygenative functionalization of amides is a long-standing challenge owing to the inertness of the resonance-stabilized amide C=O bond. In this work, a deoxygenative alkylation strategy was demonstrated, which combines amides and alkyl iodides to build structurally diverse tertiary alkylamines in a single step. Compared with previous deoxygenative alkylation of amides using organometallic reagents as functional partner, this work uses stable and easily available alkyl halides as functionalization reagents. The versatile and flexible strategy plus structural and functional diversity of readily available amides and alkyl iodides renders it highly appealing for the streamlined synthesis of tertiary amines and would be of much interest in areas such as pharmaceutical and agrochemical research.

关键词： deoxygenative alkylation amide transformation alkyl radical alkylamine visible light

同方期刊数据库

A review on the definitions of terms of sedimentary facies

在线全文

学校读者我要写书评

暂无评论

Journal of Palaeogeography 2019年第4期8卷 321-331页

作者： Zeng-zhao feng Editorial Office of Journal of Palaeogeography China University of Petroleum (Beijing)

In recent years,in some papers and manuscripts published in and submitted to the Journal of Palaeogeography(Chinese Edition and English Edition),the authors named the rocks or rock types as"microfacies"or"lithofacies",named the microfeatures in thin-sections under microscope as"microfacies",and named the macrofeatures of rocks as"macrofacies".I wrote two short papers"Words of the Editor-in-Chief—Rocks are not microfacies"(feng,Journal of Palaeogeography 19(5):II 2017)and"Words of the Editor-in-Chief—Rocks are not lithofacies"(feng,Journal of Palaeogeography 20(3):452–452,2018)which were in Chinese and published in the Journal of Palaeogeography(Chinese Edition).However,they did not attract much attention of readers in China and outside *** addition,in1980 s,some Chinese sedimentologists proposed"subfacies"and"microfacies"based on the macrofeatures of rocks from outcrops and drilling ***,the definition of this"microfacies"is totally different from the"microfacies"proposed by foreign sedimentologists in 1940 s based on the microfeatures in thin-sections under *** problems appeared repeatedly and forced me,as the Editor-in-Chief of the Journal of Palaeogeography(Chinese Edition and English Edition),to observe the policy of"A hundred flowers blossom and a hundred schools of thought contend",to write new papers"A review on the definitions of terms of sedimentary facies"both in Chinese and in English,to clarify the definitions of the terms of sedimentary facies,i.e.,"facies","lithofacies",two"microfacies","macrofacies","subfacies",etc.I hope that the new papers will attract attention of readers worldwide and they can write papers and participate in the discussion and contending of these problems,strive for getting some common understandings,and therefore promote the progress and development of sedimentology and palaeogeography.

关键词： Sedimentary facies Facies Lithofacies Microfacies Macrofacies Subfacies A hundred flowers blossom and a hundred schools of thought contend

A brief review on 7 papers from the special issue of “The environmental significance of soft-sediment deformation” of the Sedimentary Geology 344(2016)

在线全文

学校读者我要写书评

暂无评论

Journal of Palaeogeography 2017年第4期6卷 243-250页

作者： Zeng-zhao feng China University of Petroleum (Beijing)

From the viewpoint of origins of soft-sediment deformation structures（SSDS）, 7 papers（Ito et al.,2016; Jiang et al., 2016; Lunina and Gladkov, 2016; Moretti et al., 2016; Rana et al., 2016; Rodríguez-Pascua et al., 2016; Wheatley et al., 2016） selected from the special issue of ＂The environmental significance of softsediment deformation＂ of the Sedimentary Geology 344（2016） were reviewed.（1） The first paper（according to the published order） by Moretti et al. is a general review and introduction of this special issue. This special issue has made an important contribution to the study of sedimentary environments.（2） The fourth paper by Rodríguez-Pascua et al. is an excellent case study. All evidence of earthquake in this paper is reliable. The old Roman City（adjacent to Madrid, the capital of Spain） was definitely destroyed by an earthquake. This paper solved the problem that the archaeologists have not solved yet.（3） The 19 thpaper by Rana et al. is another excellent case study. It demonstrated that SSDS in the youngest modern sediments in the seismically active area, i.e., the Alaknanda Valley, Garhwal Himalaya, India, are of non-seismic origin, but with typically sedimentary origin. All evidence of sedimentary origin of SSDS in the study area is reliable.（4） The second paper by Lunina and Gladkov stated that SSDS（mainly clastic dikes） in epicentral areas of the recent earthquakes in southern Siberia were originated by earthquakes and that the clastic dikes are the most reliable indicators in the epicentral areas of earthquakes. This conclusion is right. However, it is not accurate to consider all clastic injections as ＂in-situ earthquake structures＂ in anywhere, because the clastic injections are with multiple origins.（5） The third paper by Wheatley et al. comprehensively stated the clastic pipes of the Jurassic in the Colorado Plateau, USA. However, the principal origin of the clastic pipes（columns） was possibly not originated by ＂palaeoseismic controls＂, but by ＂

关键词： Soft-sediment deformation structures(SSDS) Sedimentary environments Origins Contradictions Review Invitation

On palaeogeographic map

在线全文

学校读者我要写书评

暂无评论

Journal of Palaeogeography 2016年第1期5卷 1-27页

作者： Zeng-zhao feng China University of Petroleum (Beijing) Beijing 100083 China

The palaeogeographic map is a graphic representation of physical geographical character- istics in geological history periods and human history periods. It is the most important result of palaeogeographic study. The author, as the Editor-in-Chief oflournal of Palaeogeography, Chinese Edition and English Edition, aimed at the problems of the articles submitted to and published in the]ournal of Palaeogeography in recent years and the relevant papers and books of others, and integrated with his practice of palaeogeographic study and mapping, wrote this paper. The content mainly includes the data of palaeogeographic mapping, the prob- lems of palaeogeographic mapping method, the ＂Single factor analysis and multifactor comprehensive mapping method ---- Methodology of quantitative lithofacies palae- ogeography＇, i.e., the ＂4 steps mapping method＂, the nomenclature of each palaeogeographic unit in palaeogeographic map, the explanation of each palaeogeographic unit in palae- ogeographic map, the explanation of significance of palaeogeographic map and palae- ogeographic article, the evaluative standards of palaeogeographic map and palaeogeographic article, and the self-evaluation. Criticisms and corrections are welcome. 2016 China University of Petroleum {Beijing）. Production and hosting by Elsevier B.V. on behalf of China University of Petroleum （Beijing）. This is an open access article under

关键词： Palaeogeographic mapPalaeogeographyData is the first necessaryMethod is the key problem4 steps mapping methodThe name must match its realityEvaluative standardsTo take responsibility for authorsreaders and human society

Traversable Lorentzian Wormholes in Brans-Dicke’s and Induced Gravity Theories

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1996年第12期13卷 881-884页

作者： zhao feng LIU Liao Department of Biomedical Engineering Capital University of Medical SciencesBeijing 100054 Department of Physics Beijing Normal UniversityBeijing 100875

We generalize Visser’s method to construct traversable Lorentzian wormholes from surgically modified Friedman-Robertson-Walker spacetimes in both Brans-Dicke’s theory and induced theory of *** result shows,in both c... 详细信息

关键词： Brans Dicke theory

Gas flow characteristics of argon inductively coupled plasma and advections of plasma species under incompressible and compressible flows

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 Physics B 2018年第12期27卷 348-360页

作者： Shu-Xia zhao zhao feng Physics Department Dalian University of Technology

In this work, incompressible and compressible flows of background gas are characterized in argon inductively coupled plasma by using a fluid model, and the respective influence of the two flows on the plasma properties is specified. In the incompressible flow, only the velocity variable is calculated, while in the compressible flow, both the velocity and density variables are calculated. The compressible flow is more realistic; nevertheless, a comparison of the two types of flow is convenient for people to investigate the respective role of velocity and density variables. The peripheral symmetric profile of metastable density near the chamber sidewall is broken in the incompressible flow. At the compressible flow, the electron density increases and the electron temperature decreases. Meanwhile, the metastable density peak shifts to the dielectric window from the discharge center, besides for the peripheral density profile distortion, similar to the incompressible *** velocity profile at incompressible flow is not altered when changing the inlet velocity, whereas clear peak shift of velocity profile from the inlet to the outlet at compressible flow is observed as increasing the gas flow rate. The shift of velocity peak is more obvious at low pressures for it is easy to compress the rarefied gas. The velocity profile variations at compressible flow show people the concrete residing processes of background molecule and plasma species in the chamber at different flow rates. Of more significance is it implied that in the usual linear method that people use to calculate the residence time, one important parameter in the gas flow dynamics, needs to be rectified. The spatial profile of pressure simulated exhibits obvious spatial gradient. This is helpful for experimentalists to understand their gas pressure measurements that are always taken at the chamber outlet. At the end, the work specification and limitations are listed.

关键词： gas flow inductively coupled plasma compressible flow fluid model

A Novel Analysis of Delay and Power Consumption for Polling Schemes in the IoT

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2017年第4期22卷 368-378页

作者： Li feng Jiguo Yu feng zhao Honglu Jiang Faculty of Information Technology Macao University of Science and Technology School of Information Science and Engineering Qufu Normal University School of Computer Science and Information Security Guilin University of Electronic Technology

In the Internet of Things（IoT）, various battery-powered wireless devices are connected to collect and exchange data, and typical traffic is periodic and heterogeneous. Polling with power management is a very promising technique that can be used for communication among these devices in the IoT. In this paper, we propose a novel and scalable model to study the delay and the power consumption performance for polling schemes with power management under heterogeneous settings（particularly the heterogeneous sleeping interval）. In our model,by introducing the concept of virtual polling interval, we successfully convert the considered energy-efficient polling scheme into an equivalent purely-limited vacation system. Thus, we can easily evaluate the mean and variance of the delay and the power consumption by applying existing queueing formulae, without developing a new theoretical model as required in previous works. Extensive simulations show that our analytical results are very accurate for both homogeneous and heterogeneous settings.

关键词： 802.11 Point Coordination Function(PCF) power management queueing analysis