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Applicability limits of the DAX test in plastic bonded explosives

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Defence Technology（防务技术） 2024年第6期36卷 64-70页

作者： Martin künzel Jindrich kucera Jiri Pachman OZM Research Bliznovice 32Hrochuv Tynec 53862Czech Republic Institute of Energetic Materials Faculty of Chemical TechnologyUniversity of PardubiceStudentska 95Pardubice 53210Czech Republic

The Disc Acceleration e Xperiment(DAX)is one of the most recent experimental methods of performance characterization of new energetic materials.A cylindrical explosive charge accelerates a thin metallic disc and its velocity is measured continuously using photonic Doppler *** detonation velocity is measured *** DAX test can be used to obtain the Chapman-Jouguet(CJ)detonation pressure and to describe detonation products expansion using reduced amount of explosive.A series of DAX tests was performed at various charge diameters and disc thicknesses with semtex 1 A plastic bonded explosive and sensitized *** DAX-like evaluation was also applied to previously measured data of semtex 1A and A-IX-1 *** optimum disc thickness is determined by the disc to explosive mass ratio of *** repeatability of the semtex 1 A detonation pressure results is about four times lower compared to the pressed and liquid explosives.

关键词： Flyer plate Detonation pressure Photonic Doppler velocimetry semtex

separation and purification of tantalum from plumbomicrolite of amazonite deposit in kola Peninsula by acid leaching and solvent extraction

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Journal of Central south University 2021年第1期28卷 72-88页

作者： s M MAslOBOEVA l G ARUTYUNYAN M N PAlATNIkOV D V MANUkOVskAYA Tananaev Institute of Chemistry–subdivision of the Federal Research Centre Kola Science Centre of the Russian Academy of SciencesApatity 184209Russia

A plumbomicrolite concentrate(PMC)was leached with the mixture of HF and H2sO4,HF and HNO3 acids,*** conditions ensuring high recovery of tantalum and niobium(up to 99%)into solution,and radionuclides into insoluble residue were ***-sulfuric acid and fluoride-nitric acid schemes were proposed for PMC leaching by an extractive separation of tantalum form niobium,lead and impurities,and production of high-purity tantalum ***-1 was used as an *** conditions for production of high-purity tantalum strip solutions were defined for all stages(extraction-scrubbing-stripping).Produced tantalum compounds,such as tantalum pentoxide and potassium heptafluotanthalate,comply with the norms for high-purity substances in terms of impurities *** choice of the PMC processing scheme is determined by its profitability.

关键词： mineral plumbomicrolite tantalum niobium acid leaching radioactivity solvent extraction

New analytical exact solutions of time fractional kdV kZk equation by kudryashov methods

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Chinese Physics B 2016年第4期25卷 30-36页

作者： s saha Ray National Institute of Technology Department of Mathematics

In this paper, new exact solutions of the time fractional kdV-khokhlov-Zabolotskaya-kuznetsov （kdV-kZk） equa- tion are obtained by the classical kudryashov method and modified kudryashov method respectively. For this purpose, the modified Riemann-liouville derivative is used to convert the nonlinear time fractional kdV-kZk equation into the non- linear ordinary differential equation. In the present analysis, the classical kudryashov method and modified kudryashov method are both used successively to compute the analytical solutions of the time fractional kdV-kZk equation. As a result, new exact solutions involving the symmetrical Fibonacci function, hyperbolic function and exponential function are obtained for the first time. The methods under consideration are reliable and efficient, and can be used as an alternative to establish new exact solutions of different types of fractional differential equations arising from mathematical physics. The obtained results are exhibited graphically in order to demonstrate the efficiencies and applicabilities of these proposed methods of solving the nonlinear time fractional kdV-kZk equation.

关键词： kdV-khokhlov-Zabolotskaya-kuznetsov equation kudryashov method modified kudryashovmethod fractional complex transform modified Riemann-liouville derivative

Concordance of non-invasive mechanical and serum tests for liver fibrosis evaluation in chronic hepatitis C

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World Journal of Hepatology 2017年第8期9卷 436-442页

作者： Denise C Paranaguá-Vezozzo Adriana Andrade Daniel F C Mazo Vinicius Nunes Ana l Guedes Taisa G Ragazzo Renata Moutinho lucas s Nacif suzane k Ono Venancio A F Alves Flair J Carrilho Division of Clinical Gastroenterology and Hepatology Hospital das ClínicasDepartment of GastroenterologyUniversity of Sao Paulo School of Medicine Division of Gastroenterology School of Medical SciencesState University of Campinas Department of Pathology University of Sao Paulo School of Medicine

AIM To determine the sensitivity and specificity of liver stiffness measurement(lsM) and serum markers(sM) for liver fibrosis evaluation in chronic hepatitis *** Between 2012 and 2014,81 consecutive hepatitis C virus(HCV) patients had METAVIR score from liver biopsy compared with concurrent results from lsM [transient elastography(TE) [Fibros can~/ARFI technology(Virtual Touch~)] and sM [FIB-4/aspartate aminotransferase-toplatelet ratio index(APRI)].The diagnostic performance of these tests was assessed using receiver operating characteristic *** optimal cut-off levels of each test were chosen to define fibrosis stages F ≥ 2,F ≥ 3 and F = *** kappa index set the concordance *** Fifty point six percent were female and the median age was 51 years(30-78).Fifty-six patients(70%) weretreatment-na?*** optimal cut-off values for predicting F ≥ 2 stage fibrosis assessed by TE were 6.6 kP a,for acoustic radiation force impulse(ARFI) 1.22 m/s,for APRI 0.75 and for FIB-4 *** F ≥ 3 TE was 8.9 kP a,ARFI was 1.48 m/s,APRI was 0.75,and FIB-4 was *** F = 4,TE was 12.2 kP a,ARFI was 1.77 m/s,APRI was 1.46,and FIB-4 was *** APRI could not distinguish between F2 and F3,P = *** negative predictive value for F = 4 for TE and ARFI was 100%.kappa index values for F ≥ 3 METAVIR score for TE,ARFI and FIB-4 were 0.687,0.606 and 0.654,*** demonstrates strong concordance between all three screening methods,and moderate to strong concordance between them and APRI(kappa index = 0.507).CONClUsION Given the costs and accessibility of lsM methods,and the similarity with the outcomes of sM,we suggest that FIB-4 as well as TE and ARFI may be useful indicators of the degree of liver *** is of particular importance to developing countries.

关键词： Elastography serum markers Hepatitis C virus liver stiffness liver biopsy

Optical properties of amorphous thin film of se-Te-Ag system prepared by using thermal evaporation technique

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Progress in Natural science:Materials International 2011年第1期21卷 36-39页

作者： Madhu MIsHRA Rashmi CHAUHAN Anju kATIYAR k.k.sRIVAsTAVA Department of Physics Dayanand Braiendra Swarup D.B.S.(P.G.) CollegeKanpur(U.P.)India Department of Physics D.A-V.(P.G.) CollegeKanpur(U.P.)India Department of Physics Dayanand Brajendra Swarup D.B.S.(P.G.) CollegeKanpur(U.P.)India

Optical reflection and transmission spectra of se80-xTe20Agx(where x=0,5,10 and 15,molar percent) chalcogenide thin films have been obtained in the range 300-1 200 nm at room *** samples are prepared by melt quenching technique and thin films are obtained by using vacuum evaporation technique on glass transition at room *** present paper reports the effect of Ag contents on various optical parameters such as optical band gap,refractive index,extinction coefficient,absorption *** spectra are used for calculating these optical *** band gap Egis determined from the plot of (ahv)1/2versus *** and imaginary parts of the dielectric constant changes slightly with the variation of Ag contents in different *** film exhibits indirect band gap which increases with increasing Ag *** observed behavior is explained on the basis of Davis and Mott model for the density of *** absorption coefficient of thin films exhibits linear dependence on photon *** optical parameters are calculated by using theory of *** the optical parameters change with the variation of the film *** spectrophotometer JAsCO-UV/VIs/NIR is used to determine optical constants.

关键词： chalcogenide thin film band gap optical constant

Computing Quantum Bound states on Triply Punctured Two-sphere surface

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Chinese Physics letters 2016年第9期33卷 1-4页

作者： k.T.Chan H.Zainuddin k.A.M.Atan A.A.siddig Department of Physics Faculty of ScienceUniversiti Putra Malaysia Institute for Mathematical Research Universiti Putra Malaysia Department of Physics and Astronomy College of ScienceKing Saud University

We are interested in a quantum mechanical system on a triply punctured two-sphere surface with hyperbolic metric. The bound states on this system are described by the Maass cusp forms （MCFs） which are smooth square integrable eigenfunctions of the hyperbolic laplacian. Their discrete eigenvalues and the MCF are not known analytically. We solve numerically using a modified Hejhal and Then algorithm, which is suitable to compute eigenvalues for a surface with more than one cusp. We report on the computational results of some lower-lying eigenvalues for the triply punctured surface as well as providing plots of the MCF using GridMathematica.

关键词： of in for Computing Quantum Bound states on Triply Punctured Two-sphere surface is on MCF

Gas-solid flow in a diffuser:Effect of inter-particle and particle-wall collisions

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Particuology 2021年第4期19卷 187-200页

作者： santosh kumar senapati sukanta k.Dash CFD laboratory Department of Mechanical EngineeringIndian Institute of Technology KharagpurWest Bengal721302India

This article investigates the role of the specularity coefficient(φ,the extent of the energy dissipation due to particle-wall collisions),inter-particle restitution coefficient(e_(pp),the extent of the energy dissipation due to inter-particle collisions),and four combinations of these variables on the hydrodynamics,and the pressure recovery of the dilute gas-solid suspension in a *** investigation applies the two-fluid modeling approach along with the kinetic theory of the granular *** present investigation’s findings indicate that an increase inφor a reduction in e_(pp) reduces the pressure recovery by weakening the reverse momentum transfer phenomenon,which is recognized as the primary means for the pressure ***,in a gas-solid flow system,a higherφor smaller e_(pp) enhances the particles’trapping in the recirculation *** recirculation zone’s strength and size increase asφincreases or e_(pp) ***,an increase in the wall-particle and inter-particle interactions strengthens the sidewise displacement of the *** effect of the wall-particle and inter-particle interactions are insignificant for extremely small solid loading.

关键词： Gas-solid flow Diffuser Particle-wall collision Inter-particle collision Pressure recovery Reattachment length

soil Nitrogen Availability Is Reflected in the Bacterial Pathway

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Pedosphere 2011年第1期21卷 26-30页

作者： V.kRIVTsOV B.s.GRIFFITHs k.lIDDEll A.GARsIDE R.sAlMOND T.BEZGINOVA J.THOMPsON6 Centre for the study of Environmental Change and sustainability(CECs) School of GeoSciencesUniversity of EdinburghWest Mains RoadEdinburgh EH9 3JNScotland(UK) Department of Ecology Kharkov State University Teagasc Environment Research Institute Johnstown Castle University of Abertay Dundee SIMBIOSSchool of Science & Engineering Royal Museum of scotland Edinburgh(UK) Hope Hospital Manchester(UK) scottish Crop Research Institute InvergowrieDundeeScotland(UK)

Measurements of concentrations of easily extractable soil nitrogen(N) were carried out on samples collected at the Heron Wood Reserve,scotland,concurrently with investigations of N associated with total microbial biomass and the abundances of bacteria,fungi,and *** biota at the studied site appeared to be limited by *** was a remarkable difference between the ambient(i.e.,easily extractable N) and biomass *** abundance data of bacteria,protozoa and nematodes significantly negatively correlated with ambient N but showed positive correlations with the total microbial N *** were,however,remarkable differences between the correlation patterns exhibited by the fungal and the bacterial pathways,as fungi did not show any correlations with chemical *** differences should be taken into account whilst interpreting biological interactions both at this important site and elsewhere.

关键词： bacteria fungi nematodes protozoa woodland

Tribological behavior of lubricant-impregnated porous polyimide

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Friction 2024年第4期12卷 711-725页

作者： Jinbang lI Ningning ZHOU Janet s.s.WONG school of Mechanical Engineering and Mechanics Ningbo UniversityNingbo 315211China Beijing key laboratory of long-life Technology of Precise Rotation and Transmission Mechanisms Beijing Institute of Control EngineeringBeijing 100029China Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK

Porous materials impregnated with lubricants can be used in conditions where limited lubricant is *** this work,three porous polyimides(PPI)with different densities were ***(PAO)impregnated PPI(iPPI)discs were rubbed against steel and sapphire *** operando observations of the iPPI-sapphire contacts show that oil is released under an applied load,forming a meniscus around *** at the outlet is created at high sliding *** amount of released oil increases with increasing PPI *** moduli,E*,estimated based on the actual contact size show that trapped oil in iPPIs contributes to load *** higher speeds,tribological rehydration of the contact occurs in low density iPPI,with that E*rises with *** high density PPIs,high speeds give a constantly high E*which is limited by the viscoelastic properties of the PPI network and possibly the rate of oil *** of iPPI-steel contacts is governed by the mechanical properties of the PPI,the flow of the lubricant,and the roughness of the PPI *** low-and medium-density(highly porous,high roughness)PPIs,large amount of oil is released,and lubrication is mainly via lubricant restricted in the contact in the pores and possibly tribological *** high density(low porosity)PPI,with lower roughness,hydrodynamic lubrication is achieved which gives the lowest *** results show that polymeric porous materials for effective lubrication require the optimization of its surface roughness,stiffness,oil flow,and oil retentions.

关键词： polyimide porous material friction mechanism polymer limited lubrication