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Active catalytic species generated in situ in zirconia incorporated hydrogen storage material magnesium hydride

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Journal of Magnesium and Alloys 2022年第3期10卷 852-861页

作者： D.Pukazhselvan k.S.Sandhya Devaraj Ramasamy Aliaksandr Shaula Igor Bdikin Duncan Paul Fagg Department of Mechanical Engineering Nanoengineering Research GroupCentre for Mechanical Technology and Automation(TEMA)University of AveiroAveiro 3810-193Portugal Department of Chemistry Malankara Catholic CollegeKaliyakkavilaiTamil Nadu 629153India Department of Computational Biology and Bioinformatics University of KeralaThiruvananthapuramKerala 695581India UIDM ESTGPolytechnic Institute of Viana do CasteloViana do Castelo 4900Portugal

This study explores how zirconia additive interacts with MgH_(2)to improve its hydrogen storage *** it is confirmed that the zirconia added MgH_(2)powder releases hydrogen at a temperature of about 50℃below that of the additive free MgH_(2).Subsequent tests by X ray diffraction(XRD)and infrared(IR)spectroscopy techniques reveal that the ZrO_(2) mixed MgH_(2)powder contains ZrHx(21.5)and MgO secondary *** observation is supported by the negative Gibbs free energy values obtained for the formation of ZrH_(2)/MgO from ZrO_(2)/MgH_(2)powder *** X ray photoelectron spectroscopy(XPS)study reveals that apart from Zr^(4+)cations,Zr^(2+) and zero valent Zr exist in the *** force microscopy(AFM)study reveals that the average grain size is 20 nm and the elemental line scan profiles further proves the existence of oxygen deficient Zr bearing phase(s).This study strengthens the belief that functional metal oxide additives in fact chemically interact with MgH_(2)to make active in-situ catalysts in the MgH_(2)system.

关键词： Hydrogen storage Binary hydrides Metal oxides Additives Nanocatalysis.

Modulated orientation-sensitive terahertz spectroscopy

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Photonics Research 2016年第3期4卷 1-8页

作者： Rohit Singh Deepu koshy George Chejin Bae k.A.Niessen A.G.Markelz Department of Physics and Astronomy Depauw University Department of Physics Virginia Tech Department of Electrical Engineering University at Buffalo Department of Physics University at Buffalo

Intramolecular vibrations of large macromolecules reside in the terahertz range. In particular, protein vibrations are closely spaced in frequency, resulting in a nearly continuous vibrational density of states. This density of vibrations interferes with the identification of specific absorption lines and their subsequent association with specific functional motions. This challenge is compounded with the absorption being dominated by the solvent and local relaxational motions. A strategy for removing the isotropic relaxational loss and isolating specific vibrations is to use aligned samples and polarization-sensitive measurements. Here, we demonstrate a technique to rapidly attain the anisotropic resonant absorbance using terahertz time domain spectroscopy and a spinning sample. The technique, modulated orientation-sensitive terahertz spectroscopy(MOSTS), has a nonzero signal only for anisotropic samples, as demonstrated by a comparison between a silicon wafer and a wire grid polarizer. For sucrose and oxalic acid molecular crystals, the MOSTS response is in agreement with modeled results for the intermolecular vibrations. Further, we demonstrate that, even in the presence of a large relaxational background, MOSTS isolates underlying vibrational resonances.

关键词： THz Modulated orientation-sensitive terahertz spectroscopy

Synthesis and properties of poly(1-phenyl-1-octyne)s containing stereogenic and chromophoric pendant groups

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Science China Chemistry 2009年第10期52卷 1691-1702页

作者： LAM Jacky W.Y. JIM Cathy k.W. kWOk Hoi Sing Department of Chemistry The Hong Kong University of Science & Technology Center for Display Research The Hong Kong University of Science & Technology

Poly(1-phenyl-1-octyne)s containing different stereogenic and chromophoric pendants {-[(C6H13)C= C(C6H4-p-CO2-R)] n -R = [(1S)-endo]-(?)-borneyl (P3), (1R,2S,5R)-(?)-menthyl (P4), -C6H4-p-(1R,2S,5R)-(?)-menthyl (P5), 2-napthyl (P6), 4-biphenylyl (P7)} have been designed and synthesized. The polymers are prepared in moderate yields by WCl6-Ph4Sn and possess high molecular weights (M w up to 64000). The structures and properties of the polymers are characterized and evaluated by NMR, TGA, UV, CD, PL, and EL analyses. All the polymers are thermally stable and their temperatures for 5% weight loss locate in the range of 300 to 416°C under nitrogen. The energy band gaps of all the polymers are ～3.0 eV. Polymers P4 and P5 show CD absorptions associated with the helicity of the polymer segments. Excitation of the THF solutions of P3–P7 by UV irradiation gives strong blue lights of ～485 nm with quantum yields higher than 20%. The thin films of the polymers also emit in the same spectral region, indicative of little aggregation-caused quenching of light emission. Multilayer EL devices with a configuration of ITO/Polymer:PVk/BCP/Alq3/LiF/Al are constructed, which emit blue lights of ～487 nm. The maximum luminance and external quantum efficiency vary with the pendant groups, with P6 exhibiting the highest external quantum efficiency of 0.16%. The spectra stability of the EL devices is outstanding and the EL peak maximum experiences little change with the applied voltage.

关键词： chiral photoluminescence polyacetylene electroluminescence helicity

Analysis and optimization of drilling parameters for tool wear and hole dimensional accuracy in B_4C reinforced Al-alloy

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Transactions of Nonferrous Metals Society of China 2013年第9期23卷 2524-2536页

作者： A. TASkESEN k. kUTUkDE Manufacturing Engineering Gazi University Institute of Science and Technology Gazi University

Cutting parameters were evaluated and optimized based on multiple performance characteristics including tool wear and size error of drilled hole. Taguchi＇s L27, 3-level, 4-factor orthogonal array was used for the tests. It is shown that generally abrasive wear and built up edge （BUE） formation were seen in the tool wear, and the comer wear was also of major importance. Flank wear of the cutting tool was found to be mostly dependent upon particle mass fraction, followed by feed rate, drill hardness and spindle speed, respectively. Among the tools used, TiAlN coated carbide drills showed the best performance with regard to the tool wear as well as hole size. Grey relational analysis indicated that drill material was the more influential parameter than feed rate and spindle speed. The results revealed that optimal combination of the drilling parameters could be used to obtain both minimum tool wear and diametral error.

关键词： powder metallurgy B4C drilling tool wear hole dimensional accuracy optimization

The newly-assisted catalytic mechanism of surface hydroxyl species performed as the promoter in syngas-to-C2 species on the Cu-based bimetallic catalysts

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Green Energy & Environment 2023年第2期8卷 487-498页

作者： Chenyang Li Yuan Zhang Debao Li Baojun Wang Christopher k.Russell Maohong Fan Riguang Zhang State key Laboratory of Clean and Efficient Coal Utilization Taiyuan University of TechnologyTaiyuanShanxi030024China key Laboratory of Coal Science and Technology(Taiyuan University of Technology) Ministry of EducationChina State key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuanShanxi030001China College of Engineering and Applied Science University of WyomingLaramieWY82071USA Davidson School of Chemical Engineering Purdue UniversityWest LafayetteIN47906USA School of Civil and Environmental Engineering Georgia Institute of TechnologyAtlantaGA30332USA School of Energy Resources University of WyomingLaramieWY82071USA

In the conversion process of syngas-to-C_(2)species,the OH species are inevitably produced accompanying the production of key intermediates CH_(x)(x=1-3),traditionally,the function of surface OH species is generally accepted as the hydrogenating reactive *** work for the first time proposed and confirmed the assisted catalytic mechanism of surface OH species that performed as the promoter for syngas-to-C_(2)species on Cu-based *** and microkinetic modeling results reveal that the produced OH species accompanying the intermediates CH_(x)production on the MCu(M=Co,Fe,Rh)catalysts can stably exist to form OH/MCu catalysts,on which the presence of surface OH species as the promoter not only presented better activity and selectivity toward CH_(x)(x=1-3)compared to MCu catalysts,but also significantly suppressed CH_(3)OH production,providing enough CH_(x)sources to favor the production of C_(2)hydrocarbons and ***,the electronic properties analysis revealed the essential relationship between the electronic feature of OH/MCu catalysts and catalytic performance,attributing to the unique electronic micro-environment of the catalysts under the interaction of surface OH *** new mechanism is called as OH-assisted catalytic mechanism,which may be applied in the reaction systems related to the generation of OH species.

关键词： Syngas conversion C_(2)species Cu-based catalyst Surface OH species Assisted catalytic mechanism

Solar light assisted photocatalysis of water using a zinc oxide semiconductor

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Journal of Semiconductors 2013年第4期34卷 11-14页

作者： S.S.Shinde C.H.Bhosale k.Y.Rajpure Electrochemical Materials Laboratory Department of PhysicsShivaji UniversityKolhapur 416004MaharashtraIndia

The photocatalytic decomposition of an eco-persistent AO7 dye with sunlight in an oxygenated aque- ous suspension has been studied under a nano-crystalline hexagonal ZnO photocatalyst. The effect of substrate temperature on the structural, morphological and photoactive properties has been investigated. The degradation of the AO7 dye is achieved using a photoelectrochemical reactor module equipped with ZnO synthesized electrodes. kinetic parameters have been investigated in terms of a first order rate equation. The rate constant for this hetero- geneous photocatalysis was evaluated as a function of the initial concentration of original species. A substantial reduction in AO7 dye is achieved as analyzed from COD and TOC studies. The mechanism for the degradation could be explained on the basis of the Langmuir-Hinshelwood mechanism.

关键词： zinc oxide chemical kinetics photoelectrocatalysis organic species sunlight

Estimation of cotton yield with varied irrigation and nitrogen treatments using aerial multispectral imagery

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International Journal of Agricultural and Biological Engineering 2013年第2期6卷 37-41页

作者： Yanbo Huang Ruixiu Sui Steven J.Thomson Daniel k.Fisher Crop Production Systems Research Unit Agricultural Research ServiceUnited States Department of AgricultureStonevilleMS 38776USA

Cotton yield varies spatially within a *** variability can be caused by various production inputs such as soil properties,water management,and fertilizer *** multispectral imaging is capable of providing data and information to study effects of the inputs on yield qualitatively and quantitatively in a timely and cost-effective fashion.A 10-ha cotton field with irrigation and non-irrigation 2×2 blocks was used in this *** nitrogen application treatments were randomized with two replications within each *** plant canopy was closed,airborne multispectral images of the field were acquired using a 3-CCD MS4100 *** images were processed to generate various vegetation *** vegetation indices were evaluated for the best performance to characterize *** effect of irrigation on vegetation indices was *** for yield estimation were developed and verified by comparing the estimated and actual *** indicated that ratio of vegetation index(RVI)had a close relationship with yield(R^(2)=0.47).Better yield estimation could be obtained using a model with RVI and soil electrical conductivity(EC)measurements of the field as explanatory variables(R^(2)=0.53).This research demonstrates the capability of aerial multispectral remote sensing in estimating cotton yield variation and considering soil properties and nitrogen.

关键词： remote sensing multispectral imagery cotton yield nitrogen irrigation soil properties

LARGE STRAIN TORSION OF AXIALLY-CONSTRAINED SOLID RUBBER BARS

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Acta Mechanica Sinica 1994年第2期10卷 136-149页

作者： P.D. Wu k.W. Neale E. Van der Giessen On leave from Universite de Sherbrooke Sherbrooke Quebec Canada Laboratory for Engineering Mechanics Faculty of Mechanical Engineering and Marine Technology Delft University of Technology The Netherlands

Large strain fixed-end torsion of circular solid rubber bars is studied semi-analytically. The analyses are based on various non-Gaussian network models for rubber elasticity, some of which were proposed very recently. Results are presented in terms of predicted torque vs. twist curves and axial force vs. twist curves. In some cases, the predicted stress distributions are also given. The sensitivity of the second-order axial force to the employed models is considered. The predicted results are compared with experimental results found in the literature.

关键词： rubber network model large strain torsion

A Novel Soft Clustering Approach for Gene Expression Data

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Computer Systems Science & Engineering 2022年第12期43卷 871-886页

作者： E.kavitha R.Tamilarasan Arunadevi Baladhandapani M.k.Jayanthi kannan A Constituent College of Anna University University College of EngineeringVillupuram605103India A Constituent College of Anna University University College of EngineeringPattukkottai614701India Department of Electronics and Communication Engineering Dr.N.G.P Institute of TechnologyCoimbatore641048India Department of Computer Science Engineering Faculty of Engineering and TechnologyJAIN(Deemed to be University)Bangalore562112India

Gene expression data represents a condition matrix where each rowrepresents the gene and the column shows the condition. Micro array used todetect gene expression in lab for thousands of gene at a time. Genes encode proteins which in turn will dictate the cell function. The production of messengerRNA along with processing the same are the two main stages involved in the process of gene expression. The biological networks complexity added with thevolume of data containing imprecision and outliers increases the challenges indealing with them. Clustering methods are hence essential to identify the patternspresent in massive gene data. Many techniques involve hierarchical, partitioning,grid based, density based, model based and soft clustering approaches for dealingwith the gene expression data. Understanding the gene regulation and other usefulinformation from this data can be possible only through effective clustering algorithms. Though many methods are discussed in the literature, we concentrate onproviding a soft clustering approach for analyzing the gene expression data. Thepopulation elements are grouped based on the fuzziness principle and a degree ofmembership is assigned to all the elements. An improved Fuzzy clustering byLocal Approximation of Memberships (FLAME) is proposed in this workwhich overcomes the limitations of the other approaches while dealing with thenon-linear relationships and provide better segregation of biological functions.

关键词： Reinforcement membership centroid threshold statistics bioinformatics gene expression data