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Detection of spheriodal free oscillation excited by Peru 8.2 M_(s) earthquake with five international superconducting gravimeter data

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science China earth sciences 2005年第1期48卷 123-133页

作者： LeI Xiang'e XU Houze sUN Heping Key Laboratory of Dynamic Geodesy Institute of Geodesy and Geophysics. Chinese Academy of Sciences Wuhan 430077 China Key Laboratory of Dynamic Geodesy Institute of Geodesy and Geophysics. Chinese Academy of Sciences Wuhan 430077 China Key Laboratory of Dynamic Geodesy Institute of Geodesy and Geophysics. Chinese Academy of Sciences Wuhan 430077 China

In this paper, authors obtain the spectral peaks of the earth free oscillation and check all normal modes from 0s0 to 0s48 accurately, with the Fourier analysis and the maximum entropy spectrum method dealing jointly with six groups of the observational residual data from five international superconducting gravimeter stations. By comparing the observational results in this paper with three former groups of observations or models, authors notice an extra discrepancy between two observational 0s2 modes excited separately by Peru earthquake and Alaska earthquake, which probably mirrors the anisotropy of the earth's inner core. The analysis on the splitting 1s2 mode shows that the asymmetric factor of rotationwise spectral splitting is possible to be different from that of anti-rotationwise spectral splitting.

关键词： 8.2 Ms Peru earthquake, detection of earth free oscillation, observation of superconducting gravimeter,anisotropy of earth's inner core.

Point of Zero salt effect: Relationships with Clay Mineralogy of Representative soils of the so Paulo state, Brazil

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Pedosphere 2005年第5期15卷 545-553页

作者： M. e. ALVes A. LAVOReNTI Departamento de Física e Informática Institute de Física de So Carlos-IFSC/USP So Carlos (SP) 13560-970(Brazil). Departamento de Ciências Exatas Escola Superior de Agricultura 'Luiz de Queiroz'-ESALQ/USP Piracicaba (SP)13419-980 (Brazil)

The point of zero salt effect （PZse） is the soil pH value at which the magnitude of the variable surface charges is not changed due to variations in the ionic concentration of the soil solution. This property influences not only electrochemical phenomena occurring at the solid-solution interface but also the flocculation degree of the soil particles. In this study we investigated the relationships between the clay mineralogy and the PZse values of representative soils of the sāo Paulo state, Brazil. The results confirmed the usefulness of the difference between the soil pH values measured in 1 mol L^-1 KCl （pHKCl） and in water （pHH2O）（2 pHKCl-pHH2O） for estimating the PZse of tropical soils, except for the ones rich in exchangeable Al; furthermore, the ApH index （pHKC1 - pHH2O） was highly correlated with the difference between the PZse and pHH2O values, reiterating the △pH utility for estimating both the signal and the magnitude of the net surface charge of tropical soils. Finally, correlation and multiple regression analyses showed that the PZse value of weathered non-allophanic tropical soils tends to increase and to equal the soil pH due to the weathering-induced kaolinite destabilization and concomitant Fe- and Al-oxide accumulation.

关键词： electrochemical properties iron oxides kaolinite tropical soils weathered soils

La_(2-x)CexCu_(1-y)Zn_yO_4 perovskites for high temperature water-gas shift reaction

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Journal of Natural Gas Chemistry 2009年第2期18卷 131-138页

作者： s. s. Maluf e. M. Assaf Instituto de Química de so Carlos Universidade de So Paulo Av. Trabalhador Socarlense400 So Carlos SP 13560-970 Brazil

The performance of La2-xCexCu1-yZnyO4 perovskites as catalysts for the high temperature water-gas shift reaction （HT-WGsR） was investigated. The catalysts were characterized by eDs, XRD, BeT surface area, TPR, and XANes. The results showed that all the perovskites exhibited the La2CuO4 orthorhombic structure, so the Pechini method is suitable for the preparation of pure perovskite. However, the La1.90Ce0.10CuO4 perovskite alone, when calcined at 350/700℃, also showed a （La0.935Ce0.065）2CuO4 perovskite with tetragonal struc- ture, which produced a surface area higher than the other perovskites. The perovskites that exhibited the best catalytic performance were those calcined at 350/700℃ and, among these, La1.90Ce0.10CuO4 was outstanding, probably because of the high surface area associated with the presence of the （La0.935Ce0.065）2CuO4 perovskite with tetragonal structure and orthorhombic La2CuO4 phase.

关键词： perovskite shift reaction lanthanum copper cerium

Restructuring of plasmonic nanoparticle aggregates with arbitrary particle size distribution in pulsed laser fields

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Chinese Physics B 2016年第11期25卷 563-570页

作者： A e ershov A P Gavrilyuk s V Karpov s P Polyutov Institute of Computational Modeling Russian Academy of SciencesKrasnoyarsk 660036Russia L.V.Kirensky Institute of Physics of the Russian academy of sciences Krasnoyarsk 660036Russia siberian Federal University Krasnoyarsk 660028Russia siberian state Aerospace University Krasnoyarsk 660037Russia

We have studied processes of interaction of pulsed laser radiation with resonant groups of plasmonic nanoparticles（resonant domains） in large colloidal nanoparticle aggregates having different interparticle gaps and particle size *** processes are responsible for the origin of nonlinear optical effects and photochromic reactions in multiparticle *** describe photo-induced transformations in resonant domains and alterations in their absorption spectra remaining after the pulse action,we introduce the factor of spectral *** on calculation of changes in thermodynamic,mechanical,and optical characteristics of the domains,the histograms of the spectrum photomodification factor have been obtained for various interparticle gaps,an average particle size,and the degree of *** in spectra have been analyzed depending on the intensity of laser radiation and various combinations of size characteristics of *** obtained results can be used to predict manifestation of photochromic effects in composite materials containing different plasmonic nanoparticle aggregates in pulsed laser fields.

关键词： resonant arbitrary pulsed dipole manifestation alterations extinction remaining aggregate colloidal

To optimize splice joint between different PCF-based devices and sMF transmission medium

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Chinese Optics Letters 2009年第3期7卷 246-250页

作者： Faramarz e.seraji s.Farsinezhad Optical Communication Group Iran Telecom Research Center electrical engineering Department Semnan University

An analysis of splice loss between photonic crystal fibers （PCFs） and conventional single-mode fibers （sMFs） is presented at bending and straight conditions, by using scalar effective index method （seIM）, vectorial effective index method （VeIM）, and finite-difference frequency domain （FDFD） methods. It is shown that when there is a slight bending at the vicinity of splice joint, the spot size increases sharply at higher frequencies. On the basis of the obtained results, a mechanism to optimize the splice loss between PCFs and conventional sMFs, both with any geometry, is suggested. The results can be utilized for PCF- based devices to be jointed to sMF as a transmission medium.

关键词： Frequency domain analysis Photonic crystal fibers

Use of virtual reality in underground roof fall hazard assessment and risk mitigation

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International Journal of Mining science and Technology 2019年第4期29卷 603-607页

作者： e.Isleyen H.s.Duzgun Department of Mining engineering Colorado School of Mines

Virtual reality(VR)simulations are some of the alternative practice environments for safety *** gain experience under the most realistic conditions without being exposed to any real *** reality also serves as a tool to expedite the decision-making process where quick decisions and actions are necessities for a safe *** example of such a situation in underground mines is the failure risks in a tunnel face after *** support systems must be installed based on the stand-up time to ensure the safe access of personnel and equipment to the working ***,a competent person inspects the area to identify risks and determines the required support ***,training of a competent person requires large amount of time and *** study presents virtual reality simulations developed for improving the assessment of the roof fall hazards and taking necessary measures for mitigating the risk related to roof *** virtual reality simulation involves decision-making tasks for a particular scenario in which participants can experience creating a safe working environment in a timely ***,they are asked to identify the potential hazard in a tunnel after blasting,namely,rock fall,wedge failure or groundwater *** the hazard identification is successful,participants are requested to install rock bolts as a safety measure by selecting the bolt pattern(*** length and spacing).Finally,participants evaluate the roof fall hazard by viewing displacements around the opening,before and after the support *** study illustrates the benefits of VR in safety training as well as enhancing the decision-making process to enhance safety.

关键词： Virtual reality Hazard assessment Tunneling

Humidity sensing properties of La^(3+) and K^+ co-doped Ti_(0.9)sn_(0.1)O_2 thin films

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Journal of Rare earths 2011年第7期29卷 668-672页

作者： Mansoor Anbia s.e Moosavi Fard Research Laboratory of Nanoporous Materials Faculty of Chemistry Iran University of Science and Technology Farjam Street Narmak Tehran 16846 Iran

The humidity sensing properties of La^3＋ and K^＋ co-doped Ti0.9sn0.1O2 thin films were investigated. The humidity sensitive thin films were prepared by sol-gel method on alumina substrates. The sensing behaviors of thin films were inspected at different sintering temperatures by constructing a humidity-impedance measuring system. It was found that the addition of rare earth ion La^3＋ and alkali ion K^＋ was beneficial for improving the humidity sensitive properties of the samples and La0.003K0.5Ti0.9sn0.1O2 sintered at 500 ℃ for 4 h showed the best humidity sensing properties. The impedance of this thin film decreased from 109 to 104 Ω with excellent linearity in the humidity range of 11%-95%. Narrow hysteresis loop, prominent stability and high sensitivity were obtained. The effects of dopant con-tent and doping mechanism on humidity sensitivity were also discussed in terms of segregation of rare earth ions at grain boundaries and granularity of crystalline and influence of K^＋ on the decrease in the intrinsic resistance of the materials, and increase in the number of wa-ter adsorption sites.

关键词： humidity sensing thin film rare earths La^3+-doped K^+-doped Ti0.9sn0.1O2

structural and magnetic properties of turmeric functionalized CoFe_2O_4 nanocomposite powder

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Chinese Physics B 2016年第10期25卷 418-422页

作者： e Mehran s Farjami shayesteh M sheykhan Nanostructures Laboratory Department of Physics University of Guilan Department of Chemistry University of Guilan

The structural and magnetic properties of the synthesized pure and functionalized CoFe2O4magnetic nanoparticles(NPs) are studied by analyzing the results from the x-ray diffraction(XRD), transmission electron microscopy(TeM), FT–IR spectroscopy, thermogravimetry(TG), and vibrating sample magnetometer(VsM). To extract the structure and lattice parameters from the XRD analysis results, we first apply the pseudo-Voigt model function to the experimental data obtained from XRD analysis and then the Rietveld algorithm is used in order to optimize the model function to estimate the true intensity values. Our simulated intensities are in good agreement with the experimental peaks, therefore, all structural parameters such as crystallite size and lattice constant are achieved through this simulation. Magnetic analysis reveals that the synthesized functionalized NPs have a saturation magnetization almost equal to that of pure nanoparticles(PNPs). It is also found that the presence of the turmeric causes a small reduction in coercivity of the functionalized NPs in comparison with PNP. Our TGA and FTIR results show that the turmeric is bonded very well to the surface of the NPs. so it can be inferred that a nancomposite(NC) powder of turmeric and nanoparticles is produced. As an application, the anti-arsenic characteristic of turmeric makes the synthesized functionalized NPs or NC powder a good candidate for arsenic removal from polluted industrial waste water.

关键词： cobalt ferrite nanoparticles structural properties magnetic properties turmeric

Increasing chloride concentration causes retention of mercury in melted Arctic snow due to changes in photoreduction kinetics

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Journal of environmental sciences 2018年第6期30卷 122-129页

作者： e.A.Mann s.e.Ziegler A.steffen N.J.O'Driscoll Department of environmental science Acadia University environmental science Programme Memorial University of Newfoundland environment and Climate Change Canada Science and Technology Branch Air Quality Research Division

Mercury（Hg） in the Arctic is a significant concern due to its bioaccumulative and neurotoxic properties, and the sensitivity of Arctic environments. Previous research has found high levels of Hg in snowpacks with high chloride（Cl-） concentrations. We hypothesised that Cl- would increase Hg retention by decreasing Hg photoreduction to Hg（0） in melted Arctic snow. To test this, changes in Hg photoreduction kinetics in melted Alert, NU snow were quantified with changing Cl- concentration and UV intensity. snow was collected and melted in Teflon bottles in May 2014, spiked with 0–10 μg/g Cl-, and irradiated with 3.52–5.78 W·m-2 UV（280–400 nm）radiation in a Luz Chem photoreactor. Photoreduction rate constants（k）（0.14–0.59 hr-1） had positive linear relationships with [Cl-], while photoreduced Hg amounts（Hg（Ⅱ）red） had negative linear relationships with [Cl-]（1287–64 pg in 200 g melted snow）. Varying UV and[Cl-] both altered Hg（Ⅱ）red amounts, with more efficient Hg stabilisation by Cl- at higher UV intensity, while k can be predicted by Cl- concentration and/or UV intensity, depending on experimental parameters. Overall, with future projections for greater snowpack Cl- loading,our experimental results suggest that more Hg could be delivered to Arctic aquatic ecosystems by melted snow（smaller Hg（Ⅱ）red expected）, but the Hg in the melted snow that is photoreduced may do so more quickly（larger k expected）.

关键词： Mercury Photoreduction Arctic Melted snow