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Rapid visualization of latent fingerprints using novel caSiO_3:Sm^(3+) nanophosphors fabricated via ultrasound route

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Journal of Rare Earths 2019年第1期37卷 32-44,M0003页

作者： R.b.basavaraj G.P.Darshan b.Daruka Prasad S.c.Sharma h.Nagabhushana Prof.c.N.R.Rao centre for Advanced Materials Tumkur University Department of Physics Acharya Institute of Graduate Studies Department of Physics B M S Institute of Technology and ManagementVTU Affiliated Department of Mechanical Engineering Jain UniversityAdvisor Jain Group of Institutions

Latent fingerprints (LFPs) were the most significant identification method for individualization. Most commonly available fingerprints (FPs) in crime spot investigation were latent and patent types. Generally,LFPs were invisible and thus the effective visualization technique necessitates for the analysis of such FPs. In the past years, many traditional visualization techniques have been employed, but suffered with low resolution, sensitivity, contrast and high background noise. To overcome such limitations, we synthesized Sm^(3+) doped caSiO_3 nanophosphors (NPs) via an ultrasound irradiation route using mimosa pudica (m. p.)leaves extract as a bio-surfactant. The morphological behavior of the prepared samples was extensively studied by varying the concentration of the m. p. extract, ultrasound irradiation duration, ph level of the precursor solution and sonication power. The photoluminescence (PL) emission spectra exhibit characteristic peaks at～561,601 and 647 nm, which were attributed to^5G_(5/2)→~6h_J(J=5/2,7/2 and 9/2) transitions of Sm^(3+) *** Judd-Ofelt(J-O) intensity parameters and other radiative properties were estimated using PL data. The commission International de I'Eclairage (cIE) color coordinates were positioned in orange-red region shows average correlated color temperature (ccT) value of～3576 K. The optimized samples can be used as a labeling agent for the visualization of LFPs on various porous and non-porous surfaces under normal light irradiation. The visualized FPs reveals well defined ridge characteristics, namely whorl, loop,arch, bifurcation, eye, island, bridge, sweat pores, etc, with high sensitivity, selectivity, low contrast and background hindrance. Aforementioned results evidence that the prepared caSiO_3:Sm^(3+) NPs were promising luminescent materials for solid state lighting and forensic applications.

关键词： Ultrasonication,synthesis Photoluminescence Fingerprint Photometric properties Judd-Ofelt analysis Rare earths

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NUMERIcAL SIMULATION OF MAcRO-SEGREGATION IN SteEL INGOT DURING SOLIDIFIcATION

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Acta Metallurgica Sinica(English Letters) 2004年第3期17卷 288-294页

作者： c.W.Ma h.F.Shen T.Y.huang b.c.Liu Department of Mechanical Engineering Tsinghua University Beijing 100084 ChinaDepartment of Mechanical Engineering Tsinghua University Beijing 100084 ChinaDepartment of Mechanical Engineering Tsinghua University Beijing 100084 ChinaDepartment of Mechanical Engineering Tsinghua University Beijing 100084 China

A mathematical model coupling the momentum, energy and species conservation equa-tions was proposed to calculate the macro--segregation of Fe--c alloy ingot during solid-ification. The corresponding simulation software which concurrently solves the macro-scopic mass, momentum, energy and species conservation equations has been developedby applying the SIMPLE algorithm.The thermo--solutal convection in a Nh_4 cl--h_2O ingot is verified and the result showsgood agreement with that reported. Then macro--segregation in a steel ingot is simu-lated by using the developed program. The steel ingot is in a rectangular mold with ariser. The fluid flow is mainly induced by the temperature field and the solid fraction.The macro--segregation pattern is mainly affected by the thermo--induced convectionin the mushy zone. The negative segregation forms along the walls of the casting.The positive segregation forms at the top center of the casting into the riser. Thespecies concentration reaches the peak in the center of the ingot where solidificationends lastly.

关键词： macro-segregation thermo-solutal convection steel ingot numerical simulation

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EFFEcT OF cOPPER ADDITION ON MEchANIcAL PROPERTIES OF 4cr16Mo

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Acta Metallurgica Sinica(English Letters) 2008年第1期21卷 43-49页

作者： h.M. Geng X.c. Wu Y.A. Min h.b. Wang h.K. Zhang college of Materials Science and Engineering Shanghai University Shanghai 200072 China Special Steel branch Baoshan Iron ＆ Steel Co Ltd Shanghai 200940 China

Experiments conducted to determine the effect of copper addition on the machinability of plastic mold steel, 4cr16Mo, were presented. The machinability of mold steel 4cr16Mo was visibly improved by adding cu. The top wear of 4cr16Mo with copper was less than that without copper. The cu-rich phase had the effect of a lubricant and the heat conductivity, which reduced cutting-tool wear, improved machinability, and increased the service life of the cutting-tool. Increasing of copper addition decreased the hot-working character of 4cr16Mo. The optimal hot-working parameters for 4cr16Mo with copper were determined by the tensile test and the compression test. The rate of deformation should be adopted as 0.6 s-1. The heating-up temperature, initial forging temperature, and terminal forging temperature were 1200℃, 1150℃, and 950℃, respectively.

关键词： Machinability cutting-tool hot-shortness cu-rich phase

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Microstructural evolution and superelastic properties of ultrafine-graine d NiTi-base d shape memory alloy via sintering of amorphous ribbon precursor

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Journal of Materials Science & technology 2023年第7期138卷 80-92页

作者： W.S.cai h.Z.Lu h.Z.Li Z.Liu h.b.Ke W.h.Wang c.Yang National Engineering Research center of Near-net-shape Forming for Metallic Materials Guangdong Provincial Key Laboratory for Processing and Forming of Advanced Metallic MaterialsSouth China University of TechnologyGuangzhou 510640China Songshan Lake Materials Laboratory Dongguan 523808China Institute of Physics Chinese Academy of SciencesBeijing 100190China

NiTi-based shape memory alloys(SMAs)are considered as cutting-edge intelligent functional ***,it remains a great challenge to obtain ultrafine-grained(UFGed)bulk materials with mm-scale size as well as outstanding superelastic ***,UFGed bulk Ti_(35)Zr_(15)Ni_(35)cu_(15)NiTi-based SMA is successfully prepared via spark plasma sintering of amorphous ribbon precursor at different sintering temperatures,and microstructural evolution and superelastic properties are symmetrically *** is found that its grain size ranges from UFG to micro-grain with increased sintering temperature regard-less of the predominant b2 matrix in all bulk ***,the orientation relationships between b2 matrix and nano-scale fcc(Ti,Zr)_(2)Ni precipitate evolve from coherent to ***,the UFGed samples exhibit perfect superelasticity with the high recoverable strain of∼5.8%,the stable recov-ery rate above 99%,and the great critical stress inducing martensitic transformation higher than 1 GPa,far superior to the corresponding ones of suction-cast micro-grained TiZrNicu ***,the perfect superelasticity is attributed to the good resistance to dislocation slip or grain boundary slip by residual nano-scale amorphous phase or secondary phase of coherent and semi-coherent fcc(Ti,Zr)_(2)Ni *** addition,the gentle superelastic plateau is associated to the favorable transfer stress and the strong ability to accommodate dislocation movement,which is generated by the coherent interface between nano-scale fcc(Ti,Zr)_(2)Ni and UFGed b2 *** results suggest that spark plasma sintering of amorphous alloy precursor is a feasible route to obtaining excellent superelasticity in NiTi-based SMAs.

关键词： Shape memory alloy Amorphous alloy Microstructure Superelasticity

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Exploring one material for dual applications:A red-emitting Mg_(2)GeO_(4):Eu^(3+)nanophosphor for future generation energy efficient WLEDs and dosimetric applications

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Journal of Rare Earths 2024年第10期42卷 1835-1845页

作者： Akshay Arjun G.P.Darshan S.c.Sharma h.Nagabhushana D.V.Sunitha h.b.Premkumar Department of Physics Faculty of Mathematical and Physical SciencesM.S.Ramaiah University of Applied SciencesBengaluru560054India honorary Professor of Law and Forensic Materials Jain UniversityBengaluru560069India c.N.R.Rao centre for Advanced Materials Tumkur UniversityTumkur572103India School of Applied Sciences(Physics) REVA UniversityBengaluru560064India

The envisaged design and developme nt of individual mate rials to excavate a broader spectrum of desired properties and offer multiple applications are highly *** this in mind,a series of forsterite-structured Mg_(2)GeO_(4):Eu^(3+)(1 mol%-9 mol%)nanophosphors was synthesized via a solution combustion method using oxalyl dihydrazide as a *** X-ray diffraction patterns confirm the orthorhombic crystal system with a Puma space *** results clearly show irregularly shaped cluster-like structures with aggregation of the *** diffuse reflectance spectra,the optical energy band gap of the Mg_(2)GeO_(4):Eu^(3+)(1 mol%-9 mol%)nanophosphors was estimated and obtained to be~4.12-4.32 *** photoluminescence emission spectra exhibit intense peaks at^(5)79,589,610,661,and 707 nm,which are due to characteristic^(5)D_(0)→^(7)F_(0),^(5)D_(0)→^(7)F_(1),^(5)Do→^(7)F_(2),^(5)D_(0)→^(7)F_(3)and^(5)D_(0)→^(7)F_(4)transitions of Eu^(3+)ions,*** commission International de L'Eclairage color coordinates are gradually tuned from pale red(0.5980,0.4012)to a pure red(0.6385,0.3611)*** glow peaks showcase excellent super-linear response at low doses ofγ-irradiations,indicating that the prepared phosphor can be used in thermoluminescent personal dosimetry which is a biological tissue *** aforementioned results demonstrate that the prepared Mg_(2)GeO_(4):Eu^(3+)(1 mol%-9 mol%)nanophosphors are considered an excellent candidate for dual applications,i.e.,red component in future generation white-light-emitting diodes(WLEDs)and personal dosimetric applications.

关键词： Nanophosphors Photoluminescence Thermoluminescence Dosimetry Photometric properties Rare earths

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Structure heterogeneity in Metallic Glass: Modeling and Experiment

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Journal of Materials Science & technology 2014年第6期30卷 560-565页

作者： h.b.Ke J.F.Zeng c.T.Liu Y.Yang centre for Advanced Structural Materials Department of Mechanical and Biomedical EngineeringCity University of Hong Kong

Despite the great efforts dedicated to metallic glasses （MGs）, their structure still remains a mystery to be understood. With comparison to the existing mJciomechanical models, such as the free-volume and shear transformation zone （STZ） models, we first discuss in this article our recently proposed ＇core-shell＇ model, which contains a solid-like matrix and liquid-like inclusions. This serves as the theoretical basis to understand the structural heterogeneity in MGs in our analytical framework. After that, a scanning ultrafast nanoindentation technique is used to map out the structure heterogeneity in a Zr-based bulk metallic glass （bMG）. With these ongoing research efforts, we hope that more research work could be stimulated in the pursuit of the structure-property relation in MGs.

关键词： Metallic glass Structure heterogeneity Nanoindentation core-shell model

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cOMPOSITION TRIANGLE DIAGRAMS OF Ni-Mn-Ga MAGNETIc ShAPE MEMORY ALLOYS

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Acta Metallurgica Sinica(English Letters) 2006年第3期19卷 171-175页

作者： Y.F. Wang J.M. Wang c.b. Jiang h.b. Xu School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics Beijing 100083 China

A statistical work has been done to collect the composition ranges of Ni-Mn-Ga alloys exhibiting different structures and martensite start temperature （M,）, large magnetostrain or the co-existence of magnetic and structural transitions. The alloys with five-layered （5M）, seven-layered （7M） modulated and non-modulated （T） martensitic structures were mapped in the graph. An empirical formula has been presented to reflect the effect of elements nickel （Ni ）, manganese （ Mn ） and gallium （Ga）, on the martensite start temperature （M3）. The martensitic structure is sensitive to the composition and the martensitic transformation temperature is most drastically affected by the Ni content. The alloys with large magnetostrain or co-existence effect of the magnetic and structural transitions were also listed in a limited area.

关键词： Ni2MnGa alloy martensitic transformation magnetic shape memory alloy

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Approximate solutions of Klein-Gordon equation with improved Manning-Rosen potential in D-dimensions using SUSYQM

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chinese Physics b 2014年第12期23卷 38-43页

作者： A.N.Ikot h.hassanabadi h.P.Obong Y.E.chad Umoren c.N.Isonguyo b.h.Yazarloo Department of Physics University of Port HarcourtChoba P M B5323 Port Harcourt Nigeria Department of basic Sciences Shahrood Branch Islamic Azad UniversityShahrood Iran Theoretical Physics Group Department of Physics University of Uyo-NigeriaNigeria

In this paper, we present solutions of the Klein–Gordon equation for the improved Manning–Rosen potential for arbitrary l state in d-dimensions using the supersymmetric shape invariance method. we obtained the energy levels and the corresponding wave functions expressed in terms of Jacobi polynomial in a closed form for arbitrary l state. we also calculate the oscillator strength for the potential.

关键词： Klein–Gordon equation improved Manning–Rosen potential supersymmetric quantum mechanics(SUSYQM)

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Nano-phase transformation of composite precipitates in multicomponent Al-Mg-Si(-Sc)alloys

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Journal of Materials Science & technology 2022年第15期110卷 216-226页

作者： S.b.Wang c.F.Pan b.wei X.Zheng Y.X.Lai J.h.chen Key Laboratory of LcR Materials and Devices of Yunnan Province National Center for International Research on Photoelectric and Energy MaterialsSchool of Materials and EnergyYunnan UniversityKunming 650091China collaborative Innovation center of Renewable Energy Materials and Department of Physics Guangxi UniversityNanning 530004China center for high-Resolution Electron Microscopy College of Materials Science and EngineeringHunan UniversityChangsha 410082China

Sc-addition can significantly enhance the performance of the micro-alloyed Al-Mg-Si-Sc ***,the mechanisms by which the Sc element modifies the microstructure of the alloys are still unknown in many ***,using atomic-scale transmission electron microscopy and atomic-resolution spectroscopy,we have revealed the microstructural differences between two age-hardened Al-0.5Mg-0.4Si(wt.%)alloys with and without *** first significant effect of Sc-addition on the precipitation microstructure of the Al-Mg-Si-Sc alloy is that Sc-atoms may distribute at theβ"-precipitate/Al-matrix interface and therefore accelerate aging kinetics at the initial stage of *** second significant effect of Sc-addition is that in the transition from theβ"-hardened peak-age stage to theβ′-hardened late stage,Sc-atoms can greatly improve the stability of transitionalβ"/b'/β′composite precipitates by entering the b'-substructures and/or locating at the precipitate/Al *** such Sc-atoms effectively suppressβ"toβ'transformation and cross-sectional coarsening of bothβ"and composite precipitates,leading to much finer precipitate needles with smaller diameter but much larger length,as compared with those precipitate needles formed in the alloy without ***,the alloy with Sc-addition exhibits a much better thermal stability than that without Sc.

关键词： Al alloy Strengthening mechanism Phase transition Transmission electron microscopy

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Modelling of sediment movement in the surf and swash zones

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Acta Oceanologica Sinica 2015年第2期34卷 137-142页

作者： TOKPOhOZIN N.b. KOUNOUhEWA b. AVOSSEVOU G.Y.h. hOUEKPOhEhAM A. AWANOU c.N. Institut de Mathématiques et de Sciences Physiques (IMSP/UAc) centre béninois de la Recherche Scientifique et technique (cbRST) Laboratoire de Physique du Rayonnement (LPR/FAST-UAc)

Under the action of marine currents,non-cohesive sediments evolve by bed-load,by saltation or suspension depending on their *** authors have considered that the movement of sediment is bidimensional and modelized the effects of swell by a constant velocitynear the *** we have studied the velocity profile of fluctuating currents near the seabed and studied the movement of sediment in *** results show that in the areas of study（surf and swash）the movement of sediment occurs in a volume,and the evolution of sediment varies from an areato *** obtained theoretical profiles of the position and velocity vectors confirm the observations of several authors.

关键词： non-cohesive sediments sediment dynamics swell trajectory of sediment velocity drive

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