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Concentrated suspensions of Brownian beads in water: dynamic heterogeneities through a simple experimental technique

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Science China(Physics,Mechanics & Astronomy) 2019年第10期62卷 33-44页

作者： Raffaele Pastore Marco Caggioni Domenico Larobina Luigi Santamaria amato Francesco Greco Department of Chemical Materials and Production EngineeringUniversity of Naples FedericoⅡNapoli 80125Italy Corporate Engineering The Procter&Gamble CompanyCincinnatiWest Chester OH 45069USA Institute for Polymers Composites and BiomaterialsNational Research Council of ItalyNapoli 80055Italy ASI Agenzia Spaziale ItalianaCentro di Geodesia SpazialeMatera 75100Italy

Concentrated suspensions of Brownian hard-spheres in water are an epitome for understanding the glassy dynamics of both soft materials and supercooled molecular liquids. From an experimental point of view, such systems are especially suited to perform particle tracking easily, and, therefore, are a benchmark for novel optical techniques, applicable when primary particles cannot be resolved. Differential variance analysis（DVA） is one such novel technique that simplifies significantly the characterization of structural relaxation processes of soft glassy materials, since it is directly applicable to digital image sequences of the sample. DVA succeeds in monitoring not only the average dynamics, but also its spatio-temporal fluctuations, known as dynamic heterogeneities. In this work, we study the dynamics of dense suspensions of Brownian beads in water, imaged through digital video-microscopy, by using both DVA and single-particle tracking. We focus on two commonly used signatures of dynamic heterogeneities: the dynamic susceptibility, χ4, and the non-Gaussian parameter, α2. By direct comparison of these two quantities,we are able to highlight similarities and differences. We do confirm that χ4 and α2 provide qualitatively similar information, but we find quantitative discrepancies in the scalings of characteristic time and length scale on approaching the glass transition.

关键词： glass transition structural relaxation dynamic heterogeneities colloidal glasses

PERFORMAnCE EVALUATIOn OF THREE DIFFEREnT FAÇADE MODELS FOR SUSTAInABLE OFFICE BUILDInGS

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Journal of Green Building 2006年第4期1卷 91-103页

作者： Matthias Haase Alex amato Hong kong University Department of ArchitecturePokfulam RoadHong Kong

Sustainable development issues are currently the driving forces of many building *** building façade is critical for the architectural expression and has a large affect upon large parts of the building’s environmental *** study investigates the advantages of using multidimensional computer aided modeling and simulation to produce a sustainable façade design.A first step towards green building design is to establish a list of parameters which can then be used as design criteria,*** performance,thermal visual and acoustic comfort,*** simulation and an analysis of recent projects in Hong kong can help to determine the performance according to these design parameters whilst environmental impacts due to energy consumption are considered to be an important design parameter,it is also important for comfort criteria to be considered.

关键词： OFFICE computer architectural

Positron scattering and ionization of neon atoms—theoretical investigations

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Chinese Physics B 2010年第10期19卷 245-250页

作者： Harshit n. kothari k. n. Joshipura Department of Physics Sardar Patel University Vallabh Vidyanagar-388120 India

Although positron scattering with inert gas atoms has been studied in theory as well as in experiment, there are discrepancies. The present work reports all the major total cross sections of e＋-neon scattering at incident energies above ionization threshold, originating from a complex potential formalism. Elastic and cumulative inelastic scatterings are treated in the complex spherical e＋-atom potential. Our total inelastic cross section includes positronium formation together with ionization and excitation channels in ne. Because of the Ps formation channel it is difficult to separate out ionization cross sections from the total inelastic cross sections. An approximate method similar to electron-atom scattering has been applied to bifurcate ionization and cumulative excitation cross sections at energies from threshold to 2000 eV. Comparisons of present results with available data are made. An important outcome of this work is the relative contribution of different scattering processes, which we have shown by a bar-chart at the ionization peak.

关键词： ionization cross sections positron scattering complex potential total cross sections

Compression properties of cost-efficient porous expanded clay reinforced AA7075 syntactic foams fabricated by industrial-oriented die casting technology

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China Foundry 2024年第1期21卷 60-70页

作者： İsmail Cem Akgün Çağın Bolat Ali Gökşenli Faculty of Mechanical Engineering Istanbul Technical University34437İstanbulTurkey Faculty of Engineering Samsun University55420SamsunTurkey

In today’s manufacturing industries,hard competition between rival firms makes it compulsory for researchers to design lighter and cheaper machine components due to the megatrends of cost-effectiveness and *** this point,aluminum syntactic foams(ASFs)are new-generation engineering composites and come into the upfront as a *** to their features like low density,sufficient elongation,and perfect energy absorption ability,these advanced foams have been considerably seductive for many industrial sectors *** this study,an industrial-oriented automatic die casting technology was used for the first time to manufacture the combination of AA7075/porous expanded clay(PEC).Micro evaluations(optical and FESEM)reveal that there is a homogenous particle distribution in the foam samples,and inspections are compatible with the other ASF ***,T6 aging heat treatment was operated on one half of the produced foams to explore the probable impact of aging on the compressive *** results show that PEC particles can be an alternative to expensive hollow spheres used in the previous ***,a favorable relationship is ascertained between the aging treatment and mechanical properties such as compression strength and plateau strength.

关键词： die casting porous materials metal matrix sytanctic foams expanded clay compressive deformation

Leveraging ROTI map derived from Indonesian GnSS receiver network for advancing study of Equatorial Plasma Bubble in Southeast/East Asia

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Earth and Planetary Physics 2025年第1期9卷 101-116页

作者： Prayitno Abadi Ihsan n.Muafiry Teguh n.Pratama Angga Y.Putra Suraina Gatot H.Pramono Sidik T.Wibowo Febrylian F.Chabibi Umar A.Ahmad Wildan P.Tresna Asnawi Research Center for Climate and Atmosphere Indonesian National Research and Innovation Agency(BRIN)BandungIndonesia School of Electrical Engineering Telkom UniversityBandungIndonesia Directorate of Laboratory Management Facilities and Science and Technology Park Indonesian National Research and Innovation Agency(BRIN)PontianakIndonesia Geophysics Laboratory Master Program in PhysicsUniversitas Gadjah Mada(UGM)YogyakartaIndonesia Research Center for Space Indonesian National Research and Innovation Agency(BRIN)BandungIndonesia Indonesian Geospatial Information Agency(BIG) JakartaIndonesia Research Center for Photonics Indonesian National Research and Innovation Agency(BRIN)Tangerang SelatanIndonesia Department of Earth and Planetary Sciences Hokkaido UniversitySapporoJapan

This paper highlights the crucial role of Indonesia’s GnSS receiver network in advancing Equatorial Plasma Bubble(EPB)studies in Southeast and East Asia,as ionospheric irregularities within EPB can disrupt GnSS signals and degrade positioning *** by the Indonesian Geospatial Information Agency(BIG),the Indonesia Continuously Operating Reference Station(Ina-CORS)network comprises over 300 GnSS receivers spanning equatorial to southern low-latitude ***-CORS is uniquely situated to monitor EPB generation,zonal drift,and dissipation across Southeast *** provide a practical tool for EPB research,by sharing two-dimensional rate of Total Electron Content(TEC)change index(ROTI)derived from this *** generate ROTI maps with a 10-minute resolution,and samples from May 2024 are publicly available for further scientific *** preliminary findings from the ROTI maps of Ina-CORS are ***,the Ina-CORS ROTI maps reveal that the irregularities within a broader EPB structure persist longer,increasing the potential for these irregularities to migrate farther ***,we demonstrate that combined ROTI maps from Ina-CORS and GnSS receivers in East Asia and Australia can be used to monitor the development of ionospheric irregularities in Southeast and East *** have demonstrated the combined ROTI maps to capture the development of ionospheric irregularities in the Southeast/East Asian sector during the G5 Geomagnetic Storm on May 11,*** observed simultaneous ionospheric irregularities in Japan and Australia,respectively propagating northwestward and southwestward,before midnight,whereas Southeast Asia’s equatorial and low-latitude regions exhibited irregularities *** sharing ROTI maps from Indonesia and integrating them with regional GnSS networks,researchers can conduct comprehensive EPB studies,enhancing the understanding of EPB behavior across Southeast and East Asia and contributing significantly to ionosphe

关键词： Equatorial Plasma Bubble(EPB) GnSS receivers’network Indonesia Continuously Operating Reference Station(Ina-CORS) ionospheric map Rate of TEC change index(ROTI)map

Characteristics of a Gan-based Gunn diode for THz signal generation

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Journal of Semiconductors 2012年第8期33卷 37-43页

作者： R k Parida n C Agrawala G n Dash A k Panda ITER Siksha‘O'Anusandhan University Rengali College Sambalpur University national Institute of Science&Technology

A generalized large-signal computer simulation program for a Gunn oscillator has been developed. The properties of a Gunn diode oscillator based on the widely explored Gan, are investigated using the developed program. The results show some interesting properties in Gan Gunn diodes which are not seen in GaAs and InP diodes. An output power of 1400 kW/cm^2 is achieved from the Gan Gunn diode, as compared to 4.9 kW/cm^2 from a GaAs diode.

关键词： Gunn devices semiconductor diodes semiconductor materials power Gan

CaCO_3/TiO_2 nanoparticles Based Dye Sensitized Solar Cell

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Journal of Materials Science & Technology 2014年第4期30卷 328-334页

作者： Manveen kaur n.k.Verma nano Research Lab School of Physics and Materials ScienceThapar University

In this communication, the synthesis and structural, morphological, optical, and photo-electrochemical properties of TiO2 and CaCO3/TiO2 nanoparticles as well as their applications in dye sensitized solar cells （DSSCs）, have been reported. In an X-ray diffraction pattern of CaCO3/TiO2 nanoparticles, the peak at 29.41 ° of CaCO3 has been detected, demonstrating its coating on the surface of TiO2, which is further verified using high resolution-transmission electron microscopy, energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. The strong quenching in photoluminescence emission, in the case of CaCO3/TiO2 nanoparticles, has been attributed to the decrease in recombination rate of photo-generated electron-hole pairs. In the case of UV-visible reflectance spectra, the absorption edge for CaCO3/TiO2 nanoparticles has slightly been found to be blue-shifted as compared to bare TiO2 nanoparticles, which corresponds to an increase in energy band gap of the former. The dye desorption studies reveal that CaCO3/TiO2 electrodes adsorbed more dye than the bare TiO2 electrode. CaCO3/TiO2 based DSSC show improved photo- electrochemical properties compared to the bare TiO2 based DSSC as CaCO3 coating on mi02 forms an energy barrier, and, consequently suppressing the charge recombination, and, thus, improving the overall energy conversion efficiency （η） from 0.46% to 1.44% under the illumination of simulated light of 100 mW/cm2.

关键词： Dye sensitized solar cells (DSSCs) TiO2 nanoparticles CaCO3 Coating Recombination

numerical simulation of effect of convection-diffusion on oxygen transport in microcirculation

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Applied Mathematics and Mechanics(English Edition) 2015年第2期36卷 179-200页

作者： n.ZHAO k.IRAMInA Graduate School of Systems Life Sciences Kyushu University Department of Informatics Graduate School of Information Science and Electrical Engineering Kyushu University

The entire process of oxygen transport in microcirculation by developing a3 D porous media model is calculated numerically with coupled solid deformation-fluid seepage-convection and diffusion. The principal novelty of the model is that it takes into account volumetric deformation of both capillary and tissues resulting from capillary fluctuation. How solid deformation, fluid seepage, and convection-diffusion combine to affect oxygen transport is examined quantitatively：（1） Solid deformation is more significant in the middle of capillary, where the maximum value of volumetric deformation reaches about 0.5%.（2） Solid deformation has positive influence on the tissue fluid so that it flows more uniformly and causes oxygen to be transported more uniformly, and eventually impacts oxygen concentration by 0.1%–0.5%.（3） Convection-diffusion coupled deformation and seepage has a maximum（16%） and average（3%） increase in oxygen concentration,compared with pure molecular diffusion. Its more significant role is to allow oxygen to be transported more evenly.

关键词： porous medium microcirculation oxygen transport convection-diffusion solid deformation fluid seepage

Synthesis,Characterization and Biocompatibility of Potassium Ferrite nanoparticles

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Journal of Materials Science & Technology 2014年第1期30卷 30-36页

作者： Lavanya khanna n.k.Verma nano Research Lab School of Physics and Materials ScienceThapar University

In the present study, morphology, size distribution, structure, biocompatibility and magnetic properties of potassium ferrite nanoparticles （kFeO2 nPs）, synthesized by conventional sol-gel method have been reported. The formation of spherical nanoparticles with orthorhombic structure has been confirmed by scanning electron microscopy and X-ray diffraction. The particle size, as obtained by transmission electron microscopy has been found to be in the range of 4-7 nm. Further, the size distribution has been scrutinized using Analyse-it software, where a platykurtic feature in the size distribution was observed. Fourier transform-infrared spectroscopy and thermogravimetric analysis showed the formation of metal （Fe, k） bonds at neel temperature of 337℃. Vibrating sample magnetometer analysis revealed the superparamagnetic behaviour of the synthesized kFeO2 nPs, with saturation magnetization of 25.72 emu/g. In vitro cytotoxicity test, using MTTassay, on T cell lines （Jurkat cells） showed that kFeO2 nPs are biocompatible at a particle concentration of 100μg/ml.

关键词： Potassium ferrite nanoparticles Magnetic nanoparticles Superparamagnetic behaviour Biocompatibility Cytotoxicity