检索结果-南通市图书馆

Chinese Physics Letters 2011年第8期28卷 54-57页

作者： WANG Er-Qin LIU Fu-Hu magda arahim SFakhraddin SUN Jian-Xin Institute of Theoretical Physics Shanxi UniversityTaiyuan 030006 Department of Physics Faculty of ScienceSana'a UniversityRepublic of Yemen School of Engineering Shanxi Datong UniversityDatong 037003

The multiplicity distributions of projectile fragments emitted in interactions of different nuclei with emulsion are studied by using a multi-source *** calculated results show that the projectile fragments can be described by the model and each source contributes an exponential *** the weighted sum of the folding result of many exponential distributions,a multi-component Erlang distribution is used to describe the experimental *** relationship between the height(or width)of the distribution and the mass of the incident projectile,as well as the dependence of projectile fragments on target groups,are investigated too.

关键词： exponential distribution Collisions

Kinetics of the Reaction of 2-Chloro-3,5-dinitrobenzotriflouride with Aniline in Toluene and Methanol-Toluene Mixed Solvents

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 Journal of Chemistry 2012年第1期30卷 109-114页

作者： Fathalla magda F. Chemistry Department Faculty of ScienceAlexandria UniversityP.O.426 IbrahimiaAlexandria 21321Egypt

Kinetics of the reaction of 2-chloro-3,5-dinitrobenzotriflouride with aniline were studied in toluene, metha- nol-toluene binary solvents, benzene and chloroform. The reaction in toluene exhibits third-order kinetics consistent with aggregates of aniline. Thermodynamic parameters AH#, AS# and AG# are calculated and discussed for the reaction of 2-chloro-3,5-dinitrobenzotriflouride with aniline in methanol-toluene. Molecular complexes between aniline and the substrate are rejected spectrophotometricaly. The mechanism is studied and compared with the reac- tion in presence of pyridine. It shows an amine dependence and formation of homo and/or hetero mixed aggregates between aniline and pyridine i.e. dimer mechanism.

关键词： kinetics 2-chloro-3,5-dinitrobenzotriflouride methanol-toluene

What blockchain can do for power grids?

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Blockchain(Research and Applications) 2021年第1期2卷 15-28页

作者： magda Foti Manolis Vavalis University of Thessaly Volos38221Greece

The aim of this work is to provide an up-to-date comprehensive review of the peer-reviewed articles,the research projects and the entrepreneurial efforts that consider the utilization of blockchain technology in the energy sector in general and the power grid in *** our review study we systematically classify existing applications of blockchain technology in the energy sector according to their field of *** comprehensive and holistic picture provided aims to contribute to the body of knowledge of the applicability of blockchain technology within the energy sector and pave the way for further research in this field.

关键词： Energy Power grid Blockchain Distributed ledger technology Review

The cost of privacy on blockchain:A study on sealed-bid auctions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Blockchain(Research and Applications) 2023年第3期4卷 1-10页

作者： Menelaos Kokaras magda Foti Department of Electrical and Computer Engineering University of ThessalyVolos38221Greece UBITECH Research Department UBITECH Ltd15231AthensGreece

In order to preserve privacy in a blockchain ecosystem,the main objective is to keep a transaction's data private,such as the sender,the receiver,and the amount *** current work studies the cryptographic tools commonly used to achieve this type of privacy,primarily focusing on the Ethereum *** tools usually require many computational and storage resources,leading to additional *** anonymous auction protocol was developed as a case study to explore these costs,where hiding the identity and the amount of the bids utilizes a variety of cryptographic *** proposed implementation was compared against three sealed-bid auction protocols,which utilize similar cryptographic tools for preserving privacy throughout the auction *** results show that providing an additional level of anonymity,such as hiding someone's identity,can increase the gas cost significantly,up to 2.5 times,depending on the choice of the cryptographic tools,which determine the usage of the blockchain's storage and computational *** adjusting the level of decentralization on the application level by moving some operations off-chain and maintaining the role of the auctioneer,we show that we can maintain anonymity while reducing the gas cost by 40%.

关键词： Privacy Anonymity Blockchain Distributed ledger technology Auction

Sensitivity of a solid Eu(Ⅲ) complex towards acetonitrile vapor:Structural and spectroscopic characterization

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 Rare Earths 2020年第5期38卷 571-576页

作者： Fabio Piccinelli Veronica Paterlini magda Monari Marco Bettinelli Luminescent Materials Laboratory DBUniversita di Veronaand INSTMUdR VeronaStrada Le Grazie 1537134VeronaItaly Dipartimento di Chimica"G.Ciamician" Universita di BolognaVia Selmi 240126BolognaItaly

The Eu(Ⅲ)nitrate complex of the meso-N,N’-bis(2-pyridylmethylene)-1,2-(R,S)-cyclohexanediamine ligand was synthesized and characterized by single crystal and powder X-ray *** crystal lattice of the complex is capable of absorbing and desorbing selectively acetonitrile molecules,at 293 K upon an acetonitrile vapor pressure of^0.1×10^5 *** process,which is partially reversible,can be easily followed by both powder X-ray diffraction(P-XRD)and Eu(III)luminescence *** acetonitrile molecule,located in the outer coordination sphere of the metal ion,does not affect the radiative transition probability of 5 D0 level of Eu(Ⅲ)and also it does not activate further non-radiative channels from this *** the other hand,this molecule is capable of affecting the energy position and intensities of the crystal field components of the 5 D0→7 F2 *** complex in solid form can be considered a promising material for the optical sensing of acetonitrile vapors.

关键词： Eu(Ⅲ) X-ray diffraction Crystal structure Luminescence spectroscopy Rare earths

Salt response of the freshwater microalga Scenedesmus obliquus(Turp.)Kutz is modulated by the algal growth phase

在线全文

学校读者我要写书评

暂无评论

Journal of Oceanology and Limnology 2020年第3期38卷 802-815页

作者： Taha Mohamed EL-KATONY magda Faiz EL-ADL Department of Botany and Microbiology Faculty of ScienceDamietta UniversityNew Damietta City 34517Egypt

Growth and biochemical responses of the coenobial green alga Scenedesmus obliquus to salinity stress were monitored across different phases of *** alga was cultured on BG11 growth medium and subjected to 0,30,100,and 200 mmol/L NaCl for a period of 20 d,during which algal cultures were harvested at 4-d *** salinity-induced inhibition of algal growth was accompanied with prolongation of timing of the different growth *** sharp and progressive salinity-induced inhibition of algal growth rate during the early phase of growth points to salt shock but moderation of inhibition at the subsequent stages of growth means algal acclimation to *** concentrations of chlorophylls a and b,soluble sugars,proteins as well as those of K+and Na+in the alga exhibited peaks at the initiation of the exponential phase of growth,with increasing magnitude in proportion to the increase in the level of ***,whereas soluble sugars of the alga peaked at initiation of the exponential phase,starch concentration progressively increased with culture age,reaching saturation towards the stationary *** the salinity-induced increase in soluble sugars was most evident at the early stages of growth the reverse was true for *** present results point to fast acclimation of *** to salt stress post a brief salt shock,utilizing soluble sugars,K+and Na+for osmotic *** salinity from 0 to 200 mmol/L NaCl led to progressive increase in soluble sugars,proteins,K+and Na+concentrations of the algal cells,particularly at the early stages of ***,the salinity-induced increase in chlorophyll concentration approached a limit at 100 mmol/L NaCl whereas that in starch concentration was more evident at the later stages of growth.

关键词： carbohydrates growth phase minerals protein salt stress Scenedesmus obliquus

Proposal for a cross layer scheme for real-time wireless video

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第10期7卷 1690-1694页

作者： JEYARAJ Arulsaravana CHENG Liang EL ZARKI magda EECS Department the Henry Samueli School of Engineering University of California Irvine CA-92697 USA NVIDIA Corporation Santa Clara California CA-95050 USA CS Department DonaM Bren School of lnformation ＆ Computer Sciences University of California Irvine CA-92697 USA

This paper focuses on the design of the cross layer between the video application layer and the MIMO physical layer. MIMO physical layer research has promised an enormous increase in the capacity of wireless communication systems. Also MIMO wireless systems operate under fading conditions where the channel faces arbitrary fluctuations. Since the wireless channel changes over each coherence period, the capacity of the wireless channel, given the power constraints, changes. Hence to make efficient use of the available capacity one needs to adapt the video bit rate. However it is impossible to adapt at the application layer as changing the parameters of the video takes more time than the coherence period of the channel. In this paper we address this problem through a novel solution and also investigate its performance through a simulation study.

关键词： MIMO V-BLAST Adaptive modulation Diversity Constant bit rate (CBR) Cross layer design Power control Fine granular scalability (FGS)

How can ecosystem engineer plants boost productivity in east Mediterranean drylands

在线全文

学校读者我要写书评

暂无评论

Ecological Processes 2023年第1期12卷 425-437页

作者： Elena Constantinou Dimitrios Sarris magda Psichoudaki Javier Cabello Ioannis N.Vogiatzakis Faculty of Pure&Applied Sciences Open University of Cyprus2252 NicosiaCyprus KES Research Centre 1055 NicosiaCyprus KES College 1055 NicosiaCyprus Nireas-International Water Research Center University of CyprusP.O.Box 205371678 NicosiaCyprus Andalusian Center for the Assessment and Monitoring of Global Change University of Almería04120 AlmeríaSpain Department of Biology and Geology University of Almería04120 AlmeríaSpain.

Background Water availability is the key limiting factor for plant productivity in drylands covering ca.40%of Earth’s land *** such ecosystems to retain productivity and biodiversity under climatic change,it would be valu-able to identify/promote keystone plant species that(i)have developed strategies to more efficiently utilize moisture resources not easily accessible and(ii)improve moisture conditions for neighboring *** very deep-rooted Ziziphus lotus,considered an ecosystem engineer,is one such ***,it is not known which biotic traits:(a)canopy interception of moisture/rainfall,(b)hydraulic redistribution of deep ground moisture by roots,or non-biotic factors:(c)soil’s volume,and(d)organic matter content,*** activates/modulates to play such a ***,thus,selected dryland ecosystems where the plant dominates and measured for potential effects on the less deep-rooted Thymbra *** assessing impacts on ecosystem productivity,we measured the spatial aggregation of ca.3600 *** *** a proxy for soil moisture availability and its spatial variability,we conducted a 7-year-long study using thymes’nighttime *** extended up to 15 m away from *** The density of *** plants growing up to 5 m around *** *** growing 10-15 m away was found significantly increased(2.5-4.5 times),while their stem/leaf moisture was ca.10%higher at predawn compared to nightfall during the dry *** suggests that ecosystem productivity is driven by a greater soil moisture avail-ability around *** permitting more thyme daytime transpiration,in contrast to thymes growing further *** phenomenon appeared only under dry topsoil(during the dry season;becoming stronger during dry years).Morning dew/rainfall interception from the canopy or soil depth/organic matter did not show significant effects,leaving only the hydraulic lift properties of *** as the most likely driver for soil moisture avail

关键词： Plant–plant interaction Desertification Mediterranean Dryland Moisture content Deep root Ziziphus lotus Stress-gradient

同方期刊数据库

Translating the action of molecular motors to supramolecular polymers

在线全文

学校读者我要写书评

暂无评论

Aggregate

Aggregate 2022年第3期3卷 100-101页

作者： magda M.J.Dekker Ghislaine Vantomme Institute for Complex Molecular Systems and Laboratory of Macromolecular and Organic Chemistry Eindhoven University of TechnologyEindhovenThe Netherlands

The amplification of asymmetry from the molecular level to the macroscopic scale is an intriguing mechanism operative in natural systems to control complex *** by nature,strategies for transferring chiral information across length scales in purely synthetic systems have been investigated.[1,2]Thereof,chiral molecules are embedded into well-defined ordered supramolecular structures with the dynamics of noncovalent interactions leading to the amplification effect.

关键词： amplification of asymmetry chirality molecular motor supramolecular polymer

A Secure Elliptic Curve-Based RFID Protocol

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 Computer Science & Technology 2009年第2期24卷 309-318页

作者： Santi Martínez magda Valls Concepció Roig Josep M. Miret Francesc Giné Computer Science Department Universitat de Lleida Mathematics Department Universitat de Lleida

Nowadays, the use of Radio Frequency Identification （RFID） systems in industry and stores has increased Nevertheless, some of these systems present privacy problems that may discourage potential users. Hence, high confidence and efficient privacy protocols are urgently needed. Previous studies in the literature proposed schemes that are proven to be secure, but they have scalability problems. A feasible and scalable protocol to guarantee privacy is presented in this paper. The proposed protocol uses elliptic curve cryptography combined with a zero knowledge-based authentication scheme. An analysis to prove the system secure, and even forward secure is also provided.

关键词： elliptic curve cryptography forward security RFID zero knowledge