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ZrO2 strengthened NiAl/Cr（Mo,Hf） composite fabricated by powder metallurgy

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Progress in Natural Science:Materials International 2012年第3期22卷 231-236页

作者： L.Y. Sheng a,b, J.t. Guo c, t.F. Xi a,b, b.C. Zhang c, H.Q. Ye c a PKU-HKUSt ShenZhen-Hong Kong Institution, Shenzhen 518057, China b College of Engineering, Peking University, beijing 100871, China c Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China PKU-HKUSt ShenZhen-Hong Kong Institution Shenzhen 518057 China College of Engineering Peking University Beijing 100871 China Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

the ZrO2 ceramic particles strengthened NiAl/Cr(Mo,Hf) composite was fabricated from the rapidly solidified NiAl/Cr(Mo,Hf) pre-alloyed powder and the ZrO2 powder by powder metallurgy technique. Microstructure examination revealed that in the prepared composite NiAl and Cr(Mo) phases distributed at the eutectic cell boundary become coarse but many Cr(Mo) platelets inside the eutectic cell were broken, which was different from the original powder. Moreover, fine Ni2AlHf and Hf solid solution particles distributed uniformly in the composite, and the ZrO2 particles mainly segregated along eutectic cell boundary. In addition, twin crystal and stacking faults were observed inside of ZrO2 grains. the experimental results showed that the ZrO2 ceramic particles strengthened NiAl/Cr(Mo,Hf) composite exhibited better room temperature and high temperature mechanical properties than the NiAl/Cr(Mo,Hf) alloy, which may be attributed to the fine structure and the strengthening effect of ZrO2 particles.

关键词： NiAl intermetallics NiAl/Cr(Mo) composite Powder metallurgy ZrO2 strengthening

REE geochemistry of suspended sediments from the rivers around the Yellow Sea and provenance indicators

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Chinese Science bulletin 2003年第11期48卷 1135-1139页

作者： YANG Shouye LI Congxian C. b. Lee t. K. Na Laboratory of Marine Geology Tongji UniversityLaboratory of Marine Geology Tongji UniversitySchool of Earth and Environment of Sciences Seoul National UniversitySchool of Earth and Environment of Sciences Seoul National University Shanghai 200092 ChinaShanghai 200092 ChinaSeoul 151-742 KoreaSeoul 151-742 Korea

Rare earth element (REE) compositions of the suspended sediments from the rivers around the Yellow Sea were different in that Korean river sediments (Han, Keum and Yeongsan Rivers) yield stronger fractionations than Chinese river sediments (Changjiang, Huanghe and Yalujiang), shown by obvious enrichments of LREE (light rare earth element) relative to UCC (upper continental crust). Variations of source rock compositions in the drainage basins are responsible for the differences of REE compositions between the river sediments. REE fractionation parameters including (La/Yb)UCC and (Gd/Yb)UCC as well as the ratios of La/Sc and th/Sc can be treated as proper proxies for identifying the Chinese river sediments from those Korean river matters, and furthermore, for studying the provenances and paleoenvironmental changes of the marginal seas of China.

关键词：地球化学黄海稀有元素 REE 沉积物中国韩国

Hydrodynamics of three-phase fluidization of homogeneous ternary mixture in a conical conduit-Experimental and statistical analysis

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Chinese Journal of Chemical Engineering 2016年第10期24卷 1335-1343页

作者： R.K.Padhi D.t.K.Dora Y.K.Mohanty G.K.Roy b.Sarangi Department of Chemical Engineering GIETGunupur-765 022RayagadaOdishaIndia Department of metallurgical Engineering ICITSarangaDhenkanalOdishaIndia

Hydrodynamics of conical fluidized bed differ from that of columnar beds by the fact that a velocity gradient exists along the axial direction of the *** gas–liquid–solid fluidized bed has emerged in recent years as one of the most promising devices for three-phase *** a device is of considerable industrial importance as evident from its wide applications in chemical,refining,petrochemical,biochemical processing,pharmaceutical and food *** explore this,a series of experiments have been carried out for homogeneous well-mixed ternary mixtures of dolomite of varying compositions in a three-phase conical fluidized *** hydrodynamic characteristics determined included the bed pressure drop,bed fluctuation and bed expansion *** single and combined effects of operating parameters such as superficial gas velocity,superficial liquid velocity,initial static bed height,average particle size and cone angle on the responses have been analyzed using response surface methodology(RSM).A 25 full factorial central composite experimental design has been *** of variance(ANOVA) showed a high coefficient of determination value and satisfactory prediction second-order regression models have been *** values of bed pressure drop,bed fluctuation and bed expansion ratios have been found to agree well with the developed correlations.

关键词： Gas-liquid-solid fluidization Conical bed bed pressure drop bed fluctuation ratio and bed expansion ratio ANOVA

Analysis of morphological,structural and electrical properties of annealed tiO2 nanowires deposited by GLAD technique

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Journal of Semiconductors 2017年第5期38卷 4-10页

作者： b.Shougaijam R.Swain C.Ngangbam t.R.Lenka Microelectronics & VLSI Design Group Department of ECE National Institute of Technology Silchar Assam 788010 India Department of Electronics Engineering Parala Maharaja Engineering College Berhampur 761003 Odisha India Department of ECE National Institute of Technology Manipur 795004 India

the effect of annealing on vertically aligned tiO2 NWs deposited by glancing angle deposition（GLAD）method on Si substrate using pressed and sintered tiO2 pellets as source material is *** FE-SEM images reveal the retention of vertically aligned NWs on Si substrate after annealing *** EDS analysis of tiO2NWs sample annealed at 600 ℃ in air for 1 h shows the higher weight percentage ratio of ～2.6（i.e.,72.27%oxygen and 27.73%titanium）.the XRD pattern reveals that the polycrystalline nature of anatase tiO2 dominates the annealed NWs *** electrical characteristics of Al/tiO2-NWs/tiO2-tF/p-Si（NW device） and Al/tiO2-tF/p-Si（tF device） based on annealed samples are *** is riveting to observe a lower leakage current of ～1.32 × 10^-7 A/cm^2 at ＋1 V with interface trap density of-6.71 × 10^11eV^-1cm^-2 in NW device compared to ～2.23 × 10^-2 A/cm^2 in tF *** dominant leakage mechanism is investigated to be generally Schottky emission;however Poole-Frenkel emission also takes place during high reverse bias beyond 4 V for NWs and 3 V for tF device.

关键词： annealing GLAD morphology nanowires structural tiO2

Investigation on 1.07 μm laser emission in Nd^(3+)-doped sodium fluoroborate glasses

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Journal of Rare Earths 2012年第5期30卷 413-417页

作者： D.Umamaheswari b.C.Jamalaiah t.Sasikala G.V.Lokeswara Reddy L.Rama Moorthy Department of Physics Sri Venkateswara UniversityTirupati517 502India Department of Physics Changwon National UniversityChangwon641 773Republic of Korea

Spectroscopic and fluorescence properties of Nd 3＋ ions in sodium fluoroborate（SFb） glasses were prepared and characterized through optical absorption,emission and decay *** energy level analysis was carried out using free-ion Hamiltonian *** oscillator strengths were determined by measuring the area encompassed by the absorption peaks recorded for 1.0 mol.% Nd 3＋-doped *** Judd-Ofelt parameters（2,4,6） were used to evaluate the laser characteristic parameters such as radiative transition probability（A R）,radiative decay time（τ R）,fluorescence branching ratio（β R） and stimulated emission cross-section（σ e） for the 4 F 3/2 metastable *** fluorescence spectra for different concentrations of Nd 3＋ ions were recorded by exciting the samples at 514.5 nm Ar ＋ ion laser.

关键词： sodium fluoroborate glasses rare earth spectroscopy Judd-Ofelt theory laser materials

Strong enhancement on dye photocatalytic degradation by ball-milled tiO2:A study of cationic and anionic dyes

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Journal of Materials Science & technology 2017年第8期33卷 856-863页

作者： Z.Jia L.b.t.La W.C.Zhang S.X.Liang b.Jiang S.K.Xie D.Habibi L.C.Zhang School of Engineering Edith Cowan University270 Joondalup DriveJoondalupPerthWA 6027Australia Environmental Protection Administration of fi'an Cith Ji'an 343000China School of Mechanical and Chemical Engineering The University of Western AustraliaPerchWA 6009Australia School of Materials Science and Engineering University of Science and TechnologyBeijing 100083China School of Mechanical&Electrical Engineering finggangshan Universityfl'an 343000China

tiO2 particles with desirable properties were produced by undergoing specific durations of ball *** of the tiO2 particles before and after ball milling were investigated via X-ray diffraction（XRD）, brunauer-Emmett-teller（bEt）, particle size analysis, zeta potential, and scanning electron microscope（SEM）. the equilibrium adsorption data were well fitted to Langmuir, Freundlich, and Dubinin-Radushkevich（D-R） isotherms. Compared to the as-received tiO2（mean particle size d150= 0.78μm, specific surface area = 88.17 m^2g-1, pore volume = 0.41 cm^3g-1）, the 60 min ballmilled tiO2（d50= 0.55 μm, specific surface area = 99.48 m2g-1, pore volume = 0.48 cm3g-1） enhanced the adsorption quantity of congo red and methylene blue from 10.4 mg g-1to 13.6 mg g-1, and from17.0 mg g-1to 22.2 mg g-1, respectively; and also improved the kinetic rates from k = 0.1325 to 0.2193, and k = 0.0944 to 0.1553, respectively. Dye adsorption and degradation efficiency of congo red was enhanced in acidic p H range（2–5.14）, and methylene blue was enhanced in alkaline p H range（7.58–12）.

关键词： ball-milled tiO2 Congo red Methylene blue Equilibrium adsorption Photocatalysis

VCSEL-based Raman technology for extended reach time and reference frequency transfer systems

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Optoelectronics Letters 2019年第2期15卷 139-143页

作者： G.M.Isoe E.K.Rotich t.b.Gibbon Centre for broadband Communication Nelson Mandela University

this paper experimentally demonstrates a low-cost energy efficient alternative technique for long reach transfer of accurate reference frequency(RF) clock signals for extended reach RF distribution *** is achieved by adopting distributed forward Raman amplification and vertical cavity surface emitting laser(VCSEL) technology.A class 10 G VCSEL is directly modulated with a 2 GHz RF clock *** exploiting a forward Raman pump with the flat gain of 8.6 db, a 100.8-km-long standard single mode fiber(SMF) RF clock distribution is experimentally achieved.A maximum phase noise of-117.66 dbc/Hz at offset frequency of 100 kHz and an RF clock jitter(RMS) of 5.36 ps is experimentally measured for 100.8-km-long fiber transmission without forward Raman ***, with the adoption of forward Raman amplification, the measured phase noise and RMS improves to-86.59 dbc/Hz and 1.7 ps, *** Raman pumping offers distributed high flat gain over a wide spectra range(over 35.5 nm), while VCSELs offer cost effective broadband signal distribution, therefore keeping the network optics investment low.

关键词： technology reference amplification

Characteristics of transonic moist air flows around butterfly valves with spontaneous condensation

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Propulsion and Power Research 2015年第2期4卷 72-83页

作者： A.b.M.toufique Hasan S.Matsuo t.Setoguchib Department of Mechanical Engineering Bangladesh University of Engineering and Technology(BUET)Dhaka-1000Bangladesh Department of Advanced technology Fusion Saga UniversitySaga 8408502Japan

Effects of spontaneous condensation of moist air on the shock wave dynamics around butterfly valves in transonic flows are investigated by experimental and numerical *** symmetric valve disk shapes namely-a flat rectangular plate and a mid-plane cross-section of a prototype butterfly valve have been studied in the present *** showed that in case with spontaneous condensation,the root mean square of pressure oscillation(induced by shock dynamics)is reduced significantly with those without condensation for both shapes of the ***,local aerodynamic moments were reduced in case with condensation which is considered to be beneficial in torque requirement in case of on/off applications of valves as flow control ***,total pressure loss was increased with spontaneous condensation in both the ***,the disk shape of a prototype butterfly valve showed better aerodynamic performances compared to flat rectangular plate profile in respect of total pressure loss and vortex shedding frequency in the wake region.

关键词： transonic flow Shock waves Spontaneous condensation butterfly valves Reynolds-averaged Navier-Stokes(RANS)

Properties of SN Ia progenitors from light curves and spectra

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Frontiers of physics 2013年第2期8卷 144-167页

作者： P. Hoflich P. Dragulin J. Mitchell b. Sadler t. Diamond C. Gerardy Department of Physics Florida State University Talahassee USA FL 32306 Department of Physics Astronomy Clemson University Clemson USA SC 29634

With recent advances in theory and observations, direct connections emerge between the progenitors of type Ia Supernovae （SNe Ia） and the observed light curves and spectra. A direct link is important for our understanding of the supernovae physics, the diversity of SNe Ia and the use of SNe Ia for high-precision cosmology because the details of the explosion depends sensitively on the initial conditions and the explosion scenario（s） realized in nature. Do SNe Ia originate from SD- or DD systems, and do they lead to Mcu mass explosions or dynamical mergers？ Does the statistical distribtion of SNe Ia depend on their environment which can be expected to change with redshift？ In this contribution, we will exam from the theoretical point of view the tell-tails for this connection, their consistency with the observations, and future directions. In a first section, we present the physics of the explosion, light curves and spectral formation in a nutshell to help understanding the connection. For details of the progenitor evolution and explosion physics, we refer to reviews and the other contributions in this issue. Each of the topical sections starts with a brief general review followed by a more detailed discussion of specific results. because the youth of the field, some bias is unavoidable towards results obtained within our collaborations （and FSU）. the imprint of the metallicity, progenitor stars and properties such as the central density of the exploding WD are presented. IR spectroscopy, polarimetry and imaging of SNR remnants are discussed as a tool to test for the WD properties, magnetic fields and asymmetries. We discuss different classes of type Ia supernovae, and their environment. Possible correlations between the spectroscopic and light curve properties of SN Ia are discussed. Finally, the overall emerging picture and future developments are discussed.

关键词： supernovae: general progenitors light curves spectra