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China Foundry 2011年第1期8卷 101-106页

作者： J.Lelito p.zak J.S.Suchy W.Krajewski A.L.Greer p.Darlak Department of Foundry Engineering processes AGH University of Science and Technology Department of Materials Science & Metallurgy University of Cambridge Foundry Institute

The grain density,Nv,in the solid state after solidification of AZ91/SiC composite is a function of maximum undercooling,ΔT,of a liquid *** type of function depends on the characteristics of heterogeneous nucleation sites and number of SiC present in the *** aim of this paper was selection of parameters for the model describing the relationship between the grain density of primary phase and *** model in connection with model of crystallisation,which is based on chemical elements diffusion and grain interface kinetics,can be used to predict casting quality and its *** models have parameters,which exact values are usually not known and sometimes even their physical meaning is under *** parameters can be obtained after mathematical analysis of the experimental *** composites with 0,1,2,3 and 4wt.% of SiC particles were *** AZ91 alloy was a matrix of the composite reinforcement SiC *** composite was cast to prepare four different thickness *** were taken from the region near to the thermocouple,to analyze the undercooling for different composites and thickness plates and its influence on the grain *** microstructure and thermal analysis gave set of values that connect mass fraction of SiC particles,and undercooling with grain *** values were used to approximate nucleation model adjustment *** model can be very useful in modelling composites microstructure.

关键词： heterogeneous nucleation mass fraction of SiC particles AZ91/SiC composite grain density mathematical modelling

试验确定AZ91/SiC复合材料异质形核模型中决定于SiC质量分数和过冷度的晶粒密度函数

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铸造 2011年第3期60卷 224-228页

作者： J.Lelito p.zak J.S.Suchy W.Krajewski A.L.Greer p.Darlak 申泽骥(翻译) AGH科技大学铸造工程技术系波兰克拉科夫Mickiewicza3030-059 剑桥大学材料科学和冶金系英国Pembroke StreetCambridge CB2 3QZ 铸造研究所波兰克拉科夫Zakopianka7330-418 不详

镁合金及其复合材料作为重要的轻质材料在汽车和航空工业中的应用一直引人注目。由于镁不能形成任何稳定的碳化物,SiC颗粒被大量用于增强镁基复合材料。AZ91/SiC复合材料凝固后固态晶粒密度NV是合金液态最大过冷度ΔT的函数。这类函数... 详细信息

镁合金及其复合材料作为重要的轻质材料在汽车和航空工业中的应用一直引人注目。由于镁不能形成任何稳定的碳化物,SiC颗粒被大量用于增强镁基复合材料。AZ91/SiC复合材料凝固后固态晶粒密度NV是合金液态最大过冷度ΔT的函数。这类函数决定于异质形核位置特征与合金中存在的SiC数量。本文的目的是为描述初生相晶粒密度与过冷度关系的模型选择参数。这一模型与基于化学元素扩散和晶界动力学的结晶模式有关,能够用于预测铸件质量及其显微组织。形核模型通常有未知确切值的参数,甚至其物理意义都是待讨论的,对试验数据进行分析之后可以获得这些参数。制备了SiC强化的AZ91合金基复合材料,其中SiC颗粒含量分别为0、1%、2%、3%和4%(质量分数)。把这种复合材料铸造成具有4种厚度的试验板。从热电偶测温点附近获取数据,分析不同复合材料与不同厚度试板的过冷度及其对晶粒尺寸的影响。显微组织和热分析给出的一套数据建立了晶粒尺寸与SiC颗粒质量分数及过冷度联系,这些数据用于近似形核模型的参数调节。获得的模型在模拟复合材料显微组织方面是非常有用的。

关键词：异质形核 SiC颗粒质量分数 AZ91/SiC复合材料晶粒密度数学模拟

Experimental Determination of Grain Density Function Depends on Mass Fraction of SiC and Undercooling in AZ91/SiC Composite Heterogeneous Nuclation Model

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Experimental Determination of Grain Density Function Depends...

Demonstration of laser pulse amplification by stimulated Brillouin scattering

第69届世界铸造会议暨2010中国铸造活动周

作者： J.Lelito p.zak J.S.Suchy W.Krajewski A.L.Greer p.Darlak Department of Foundry Engineering processes AGH University of Science and TechnologyMickiewicza 3030-059 KrakowPoland Department of Materials Science & Metallurgy University of CambridgePembroke StreetCambridge CB2 3QZUK Foundry Institute Zakopianka 7330-418KrakowPoland

Magnesium alloys and their composites have been attracting attention as an important lightweight material and are being utilized in the automobile and aerospace *** terms of the reinforcement in magnesium - based composites,the SiC particles are extensively used because magnesium cannot form any stable carbide. The grain density in the solid state N after solidification of AZ91/SiC composite is a function of maximum undercooling of a liquid alloy△*** type of function depends on the characteristics of heterogeneous nucleation sites and number of SiC present in the alloy. The aim of this paper was selection of parameters for the model describing the relationship between the grain density of primary phase and *** model in connection with model of crystallisation,which is based on chemical elements diffusion and grain interface kinetics,can be used to predict casting quality and its *** models have parameters,which exact values are usually not known and sometimes even their physical meaning is under discussion. Those parameters can be obtained after mathematical analyze of the experimental data. The composite with 0,1,2,3 and 4 wt.%of SiC particles were *** AZ91 alloy was a matrix of the composite reinforcement SiC *** composite was casted to prepare four different thickness plates. They were taken from the region near to the thermocouple,to analyze the undercooling for different composites and thickness plates and its influence on the grain size. The microstructure and thermo analyze gave set of values that connect mass fraction of SiC particles,and undercooling with grain *** values were used to approximate nucleation model adjustment *** model can be very useful in modelling composites microstructure.

关键词： heterogeneous nucleation mass fraction of SiC particles AZ91/SiC composite grain density mathematical modelling

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High power Laser Science and Engineering 2014年第4期 46-51页

作者： E.Guillaume K.Humphrey H.Nakamura R.M.G.M.Trines R.Heathcote M.Galimberti Y.Amano D.Doria G.Hicks E.Higson S.Kar G.Sarri M.Skramic J.Swain K.Tang J.Weston p.zak E.p.Alves R.A.Fonseca F.Fi ′uza H.Habara K.A.Tanaka R.Bingham M.Borghesi Z.Najmudin L.O.Silva p.A.Norreys Laboratoire d'Optique Appliqu′ee Ecole PolytechniquePalaiseau 91128 France STFC Rutherford Appleton Laboratory Didcot Oxon OX11 0QX United Kingdom University of Strathclyde Glasgow G11XQ United Kingdom Blackett Laboratory Imperial College London Prince Consort RoadLondon SW7 2BZ United Kingdom Graduate School of Engineering Osaka University Queens University Belfast Belfast BT7 1NN United Kingdom University of Oxford Parks RoadOxford OX1 3PU United Kingdom

The energy transfer by stimulated Brillouin backscatter from a long pump pulse(15 ps) to a short seed pulse(1 ps)has been investigated in a proof-of-principle demonstration experiment. The two pulses were both amplified in different beamlines of a Nd:glass laser system, had a central wavelength of 1054 nm and a spectral bandwidth of 2 nm, and crossed each other in an underdense plasma in a counter-propagating geometry, off-set by 10?. It is shown that the energy transfer and the wavelength of the generated Brillouin peak depend on the plasma density, the intensity of the laser pulses, and the competition between two-plasmon decay and stimulated Raman scatter instabilities. The highest obtained energy transfer from pump to probe pulse is 2.5%, at a plasma density of 0.17 ncr, and this energy transfer increases significantly with plasma density. Therefore, our results suggest that much higher efficiencies can be obtained when higher densities(above0.25ncr) are used.

关键词： laser–plasma interactions optical pulse generation and compression stimulated Brillouin and Raman scattering ultra-fast optical processes

Opportunities for tidal range projects beyond energy generation:Using Mersey barrage as a case study

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Frontiers of Architectural Research 2019年第4期8卷 620-633页

作者： Sean petley Daneel Starr Linda parish zak Underwood George A.Aggidis Department of Engineering Lancaster UniversityGillow AvenueLancasterLA174YWUK School of Architecture Liverpool UniversityLeverhulme BuildingLiverpoolL697ZNUK

Currently there is renewed interest in harnessing the vast tidal resource to combat the twin challenges of climate change and energy ***,within the UK no tidal barrage proposals have passed the development stage,this is due to a combination of high cost and environmental *** paper demonstrates how a framework,such as the North West Hydro Resource Model can be applied to tidal barrages,with the Mersey barrage as a case *** model materialised in order to provide developers with a toot to successfully identify the capacity of hydropower schemes in a specific location.A key feature of the resource model is the understanding that there is no single barrier to the utilisation of small hydropower but several obstacles,which together impede ***,this paper contributes in part to a fully holistic treatment of tidal barrages,recognising that apart from energy generation,other environmental,societal and economic opportunities arise and must be fully investigated for robust *** study demonstrates how considering the societal needs of the people and the necessity for compensatory habitats,for example,an organic architectural design has developed,which aims to enhance rather than detract from the Mersey.

关键词： Renewable energy Tidal power Tidal barrage Mersey estuary Architectural concepts Environmental concepts

Modelling of composite crystallization

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China Foundry 2012年第2期9卷 184-188页

作者： Jozef Szczepan Suchy Janusz Lelito Beata Gracz pawel Leszek zak Halina Krawiec AGH University of Science and Technology Faculty of Foundry Engineering

Metal matrix composites(MMCs)have received much attention due to their promising advanced mechanical *** aim of this work is to create a micro-macro model of composite *** developed model is coupled with the process of heat flow in the macroscopic scale,resulting from the heat emission during the nucleation and the growth of *** into account both of these phenomena,the proposed model is distinguished by a good reflection of ***,the presented model assumes that the function of grain density depends on the maximal supercooling and the mass volume of the reinforcement phase *** knowledge of the equations,describing the function of grain density depending on the degree of supercooling,is necessary in the,more and more often used,numerical modelling of the casting structure.

关键词： modelling crystallization composite grain density

WS2 nanoflakes from nanotubes for electrocatalysis

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Nano Research 2013年第12期6卷 921-928页

作者： Charina L. Choi Ju Feng Yanguang Li Justin Wu Alia zak Reshef Tenne Hongjie Dai Department of Chemistry Stanford University California 94305 USA Department of Science Holon Academic Institute of Technology Holon 58102 Israel Department of Materials and Interfaces Weizmann Institute Rehovot 76100 Israel

Next-generation catalysts for water splitting are crucial towards a renewable hydrogen economy. MoS2 and WS2 represent earth-abundant, noble metal cathode alternatives with high catalytic activity at edge sites. One challenge in their development is to nanostructure these materials in order to achieve increased performance through the creation of additional edge sites. In this work, we demonstrate a simple route to form nanostructured-WS2 using sonochemical exfoliation to break interlayer and intralayer bonds in WS2 nanotubes. The resulting few-layer nanoflakes are -100 nm wide with a high density of edge sites. WS2 nanoflakes are utilized as cathodes for the hydrogen evolution reaction （HER） and exhibit superior performance to WS2 nanotubes and bulk particles, with a lower onset potential, shallower Tafel slope and increased current density. Future work may employ ultra-small nanoflakes, dopant atoms, or graphene hybrids to further improve electrocatalytic activity.

关键词： tungsten disulfide nanotubes nanostructuring hydrogen evolution

preparation, characterization, and antibacterial activity of γ-irradiated silver nanoparticles in aqueous gelatin

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International Journal of Minerals,Metallurgy and Materials 2013年第4期20卷 403-409页

作者： Majid Darroudi Mansor B. Ahmad Mohammad Hakimi Reza Zamiri Ali Khorsand zak Hasan Ali Hosseini Mohsen Zargar Department of Modern Sciences and Technologies School of Medicine Mashhad University of Medical Sciences Department of Chemistry Faculty of Science Universiti Putra Malaysia Chemistry Department Payame Noor University Department of Materials Engineering and Ceramic CICECO University of Aveiro Electroceramics and Materials Lab. Physics Department Faculty of Science Ferdowsi University of Mashhad Faculty of Science Qom Branch Islamic Azad University

Colloidal silver nanoparticles （Ag-Nps） were obtained through γ-irradiation of aqueous solutions containing AgNO3 and gelatin as a silver source and stabilizer, respectively. The absorbed dose of γ-irradiation influences the particle diameter of the Ag-Nps, as evidenced from surface plasmon resonance （SpR） and transmission electron microscopy （TEM） images. When the γ-irradiation dose was increased （from 2 to 50 kGy）, the mean particle size was decreased continuously as a result of γ-induced Ag-Nps fragmentation. The antibacterial properties of the Ag-Nps were tested against Methicillinresistant Staphylococcus aureus （MRSA）（Gram-positive） and pseudomonas aeruginosa （p.a）（Gram-negative） bacteria. This approach reveals that the γ-irradiation-mediated method is a promising simple route for synthesizing highly stable Ag-Nps in aqueous solutions with good antibacterial properties for different applications.

关键词： silver nanoparticles silver nitrate gelatin gamma rays irradiation bacteria

Entanglement in Livings

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Journal of Quantum Information Science 2012年第3期2卷 66-77页

作者： Michail zak Jet propulsion Laboratory California Institute of Technology Pasadena USA

This paper discusses quantum-inspired models of Livings from the viewpoint of information processing. The model of Livings consists of motor dynamics simulating actual behavior of the object, and mental dynamics representing evolution of the corresponding knowledge-base and incorporating it in the form of information flows into the motor dynamics. Due to feedback from mental dynamics, the motor dynamics attains quantum-like properties: its trajectory splits into a family of different trajectories, and each of those trajectories can be chosen with the probability prescribed by the mental dynamics The paper concentrates on discovery of a new type of entanglement that correlates the probabilities of actions of Livings rather than the actions themselves.

关键词： Entanglement Information Motor/Mental Dynamics probability Feedback

Toward Quantum-Inspired Model of Mind

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Journal of Quantum Information Science 2014年第1期4卷 22-43页

作者： Michail zak Jet propulsion Laboratory California Institute of Technology Pasadena USA

This paper proposes a mathematical formalism for describing the machinery of human mind creativity. Since some functions of mind support discreteness of cognition, but others support its continuity, while time in physics is always continuous, an attempt to overcome the continuous/discrete duality of mind performance is implemented via utilization of special critical points: terminal attractors and repellers that act as autonomous biological clock. In this paper, attention is concentrated upon the discrete mode of the mind activity since the continuous mode was introduced and discussed in details in our previous publications. The fundamental novelty of the model is in its capability to move from disorder to order without external inputs in violation of the second law of thermodynamics;that suggests that this kind of dynamics requires extension of modern physics to include physics of life. Conceptually the discrete model links to its continuous version represented by a hypothetical particle of life that is briefly discussed prior to derivation of the discrete model. However, the discrete model should be considered as the next step in study of mind dynamics since it provides a bridge to mathematical origin of self-generated novelties in such brunches as mathematical logic and linguistic, i.e. the highest level activities of human mind. The proposed model deals with rules of mind activity rather than with its content.

关键词： Mind Creativity Terminal Singularities Biological Clock