Gold Nanoparticle-based Surface-enhanced Raman Scattering Fe(III) Ion Sensor

International Nuclear Information System (INIS)

Ly, Nguyen Hoang; Joo, Sang-Woo; Cho, Kwang Hwi

2015-01-01

We performed density functional theory (DFT) calculations of 4-aminobenzo-15-crown-5 (4AB15C5) in conjugation with 4-mercaptobenzoic acid (4MCB) with the polarizable continuum model (PCM) while considering the aqueous media. After specific binding of the ferric ion onto the 4MCB.4AB15C5 compound, the Raman frequencies and intensities were estimated by DFT calculations with the PCM. It was predicted that the Raman intensities became significantly increased upon binding of the ferric ion. 4MCB.4AB15C5 could be assembled on gold nanoparticles (AuNPs) via the cleavage of the thiol bond. Colorimetric and UV.Vis absorption spectroscopy indicated that AuNPs became significantly aggregated in the presence of 1.10 mM of the ferric ion. Surface-enhanced Raman scattering (SERS) of 4MCB.4AB15C5 was used to identify the dissimilar spectral behaviors that yield a difference in intensity in the presence of the ferric ion. These changes were not observed in the other biological ions Zn 2+ , Mn 2+ , Fe 2+ , Na + , K + , Ca 2+ , Mg 2+ , NH 4+ , and Co 2+ . This study indicated that 4AB15C5 could be used to detect ferric ions in aqueous AuNP solutions by a combined method of colorimetric, UV.Vis absorption, and Raman spectroscopy. AuNPs.[4MCB. 4AB15C5] can thus be utilized as a selective turn-on sensor to Fe3 + in aqueous solutions above 1 mM.

Slowing down of 1.3-3.5 MeV/u Fe, Kr and I ions in ten metals

Energy Technology Data Exchange (ETDEWEB)

Alanko, T. E-mail: tommi.alanko@phys.jyu.fi; Hyvoenen, J.; Kylloenen, V.; Mueller, S.; Raeisaenen, J.; Virtanen, A

2000-09-01

Stopping powers for 1.3-3.5 MeV/u {sup 56}Fe, {sup 80,84}Kr and {sup 127}I ions in Mg, V, Fe, Co, Ni, Cu, Nb, Sn, Ta and Au have been determined by a transmission technique exposing the metallic sample foils to the direct ion beam. No previous data have been published for Mg, V, Fe, Co, Nb, Sn or Ta stopping media with these ion energies. The experimental results are compared with parametrizations of the stopping powers found in the literature (SRIM-2000 and Hubert's parametrization). Discrepancies as high as 21 and 16% are observed for SRIM and Hubert's parametrization, respectively. However, there is agreement between the present results and other experimental data available at corresponding ion velocities for {sup 84}Kr and {sup 56}Fe in Ni, Cu, and Au.

Synthesis and application of strawberry-like Fe3O4-Au nanoparticles as CT-MR dual-modality contrast agents in accurate detection of the progressive liver disease.

Science.gov (United States)

Zhao, Hui Y; Liu, Sen; He, Jian; Pan, Chao C; Li, Hui; Zhou, Zheng Y; Ding, Yin; Huo, Da; Hu, Yong

2015-05-01

Development of non-invasive assay for the accurate diagnosis of progressive liver diseases (e.g., fatty liver and hepatocellular carcinoma (HCC)) is of great clinical significance and remains to be a big challenge. Herein, we reported the synthesis of strawberry-like Fe3O4-Au hybrid nanoparticles at room temperature that simultaneously exhibited fluorescence, enhanced X-ray attenuation, and magnetic properties. The results of in vitro fluorescence assay showed that the nanoparticles had significant photo-stability and could avoid the endosome degradation in cells. The in vivo imaging of normal mice demonstrated that the Fe3O4-Au nanoparticles provided 34.61-fold contrast enhancement under magnetic resonance (MR) guidance 15 min post the administration. Computed tomography (CT) measurements showed that the highest Hounsfield Unit (HU) was 174 at 30 min post the injection of Fe3O4-Au nanoparticles. In vivo performance of the Fe3O4-Au nanoparticles was further evaluated in rat models bearing three different liver diseases. For the fatty liver model, nearly homogeneous contrast enhancement was observed under both MR (highest contrast ratio 47.33) and CT (from 19 HU to 72 HU) guidances without the occurrences of focal nodules or dysfunction. For the cirrhotic liver and HCC, pronounced enhancement under MR and CT guidance could be seen in liver parenchyma with highlighted lesions after Fe3O4-Au injection. Furthermore, pathological, hematological and biochemical analysis revealed the absence of acute and chronic toxicity, confirming the biocompatibility of our platform for in vivo applications. Collectively, These Fe3O4-Au nanoparticles showed great promise as a candidate for multi-modality bio-imaging. Copyright © 2015 Elsevier Ltd. All rights reserved.

Magnetic properties and microstructure study of high coercivity Au/FePt/Au trilayer thin films

International Nuclear Information System (INIS)

Chen, S.K.; Yuan, F.T.; Liao, W.M.; Hsu, C.W.; Horng, Lance

2006-01-01

High-coercivity Au(60 nm)/FePt(δ nm)/Au(60 nm) trilayer samples were prepared by sputtering at room temperature, followed by post annealing at different temperatures. For the sample with δ=60 nm, L1 ordering transformation occurs at 500 deg. C. Coercivity (H c ) is increased with the annealing temperature in the studied range 400-800 deg. C. The H c value of the trilayer films is also varied with thickness of FePt intermediate layer (δ), from 27 kOe for δ=60 nm to a maximum value of 33.5 kOe for δ=20 nm. X-ray diffraction data indicate that the diffusion of Au atoms into the FePt L1 lattice is negligible even after a high-temperature (800 deg. C) annealing process. Furthermore, ordering parameter is almost unchanged as δ is reduced from 60 to 15 nm. Transmission electron microscope (TEM) photos indicate that small FePt Ll particles are dispersed amid the large-grained Au. We believe that the high coercivity of the trilayer sample is attributed to the small and uniform grain sizes of the highly ordered FePt particles which have perfect phase separation with Au matrix

Very high coercivities of top-layer diffusion Au/FePt thin films

International Nuclear Information System (INIS)

Yuan, F.T.; Chen, S.K.; Liao, W.M.; Hsu, C.W.; Hsiao, S.N.; Chang, W.C.

2006-01-01

The Au/FePt samples were prepared by depositing a gold cap layer at room temperature onto a fully ordered FePt layer, followed by an annealing at 800 deg. C for the purpose of interlayer diffusion. After the deposition of the gold layer and the high-temperature annealing, the gold atoms do not dissolve into the FePt Ll 0 lattice. Compared with the continuous FePt film, the TEM photos of the bilayer Au(60 nm)/FePt(60 nm) show a granular structure with FePt particles embedded in Au matrix. The coercivity of Au(60 nm)/FePt(60 nm) sample is 23.5 kOe, which is 85% larger than that of the FePt film without Au top layer. The enhancement in coercivity can be attributed to the formation of isolated structure of FePt ordered phase

Heterojunction metal-oxide-metal Au-Fe{sub 3}O{sub 4}-Au single nanowire device for spintronics

Energy Technology Data Exchange (ETDEWEB)

Reddy, K. M., E-mail: mrkongara@boisestate.edu; Punnoose, Alex; Hanna, Charles [Department of Physics, Boise State University, Boise, Idaho 83725 (United States); Padture, Nitin P. [School of Engineering, Brown University, Providence, Rhode Island 02912 (United States)

2015-05-07

In this report, we present the synthesis of heterojunction magnetite nanowires in alumina template and describe magnetic and electrical properties from a single nanowire device for spintronics applications. Heterojunction Au-Fe-Au nanowire arrays were electrodeposited in porous aluminum oxide templates, and an extensive and controlled heat treatment process converted Fe segment to nanocrystalline cubic magnetite phase with well-defined Au-Fe{sub 3}O{sub 4} interfaces as confirmed by the transmission electron microscopy. Magnetic measurements revealed Verwey transition shoulder around 120 K and a room temperature coercive field of 90 Oe. Current–voltage (I-V) characteristics of a single Au-Fe{sub 3}O{sub 4}-Au nanowire have exhibited Ohmic behavior. Anomalous positive magnetoresistance of about 0.5% is observed on a single nanowire, which is attributed to the high spin polarization in nanowire device with pure Fe{sub 3}O{sub 4} phase and nanocontact barrier. This work demonstrates the ability to preserve the pristine Fe{sub 3}O{sub 4} and well defined electrode contact metal (Au)–magnetite interface, which helps in attaining high spin polarized current.

Slowing down of 1.3-3.5 MeV/u Fe, Kr and I ions in ten metals

CERN Document Server

Alanko, T; Kylloenen, V; Müller, S; Raeisaenen, J; Virtanen, A

2000-01-01

Stopping powers for 1.3-3.5 MeV/u sup 5 sup 6 Fe, sup 8 sup 0 sup , sup 8 sup 4 Kr and sup 1 sup 2 sup 7 I ions in Mg, V, Fe, Co, Ni, Cu, Nb, Sn, Ta and Au have been determined by a transmission technique exposing the metallic sample foils to the direct ion beam. No previous data have been published for Mg, V, Fe, Co, Nb, Sn or Ta stopping media with these ion energies. The experimental results are compared with parametrizations of the stopping powers found in the literature (SRIM-2000 and Hubert's parametrization). Discrepancies as high as 21 and 16% are observed for SRIM and Hubert's parametrization, respectively. However, there is agreement between the present results and other experimental data available at corresponding ion velocities for sup 8 sup 4 Kr and sup 5 sup 6 Fe in Ni, Cu, and Au.

Fully stripped heavy ion yield vs energy for Xe and Au ions

International Nuclear Information System (INIS)

Thieberger, P.; Wegner, H.E.; Alonzo, J.; Gould, H.; Anholt, R.E.; Meyerhof, W.E.

1985-01-01

The Bevalac is now capable of accelerating U-238 ions to approximately 1 GeV/amu and measurements have shown that fully stripped U-238 ions are produced with good yield at these energies. However, knowing the stripping yields at different energies for U-238 does not allow an accurate prediction for other, lower Z projectiles. Consequently, extensive stripping yield measurements were made for Au-197 and Xe-139 ions. In addition to the stripping measurements from the direct Bevalac beam, pickup measurements were also made with specially prepared bare, one electron, and two electron ions. Since many research groups are considering heavy ion storage rings and/or synchrotrons, the pickup cross section for bare ions is important to estimate beam lifetime in terms of the average machine vacuum. Since the Mylar target provides a pickup probability similar to air, a preliminary analysis of the Xe 54+ and U 92+ data are presented along with predictions for other ions ranging down to Fe 26+ . 11 refs., 3 figs., 1 tab

Fully stripped heavy ion yield vs energy for Xe and Au ions

Energy Technology Data Exchange (ETDEWEB)

Thieberger, P.; Wegner, H.E.; Alonzo, J.; Gould, H.; Anholt, R.E.; Meyerhof, W.E.

1985-01-01

The Bevalac is now capable of accelerating U-238 ions to approximately 1 GeV/amu and measurements have shown that fully stripped U-238 ions are produced with good yield at these energies. However, knowing the stripping yields at different energies for U-238 does not allow an accurate prediction for other, lower Z projectiles. Consequently, extensive stripping yield measurements were made for Au-197 and Xe-139 ions. In addition to the stripping measurements from the direct Bevalac beam, pickup measurements were also made with specially prepared bare, one electron, and two electron ions. Since many research groups are considering heavy ion storage rings and/or synchrotrons, the pickup cross section for bare ions is important to estimate beam lifetime in terms of the average machine vacuum. Since the Mylar target provides a pickup probability similar to air, a preliminary analysis of the Xe/sup 54 +/ and U/sup 92 +/ data are presented along with predictions for other ions ranging down to Fe/sup 26 +/. 11 refs., 3 figs., 1 tab.

A contribution to the investigation of the properties of the Au-Fe system

International Nuclear Information System (INIS)

Vano, M.; Sitek, J.; Cirak, J.

1976-01-01

Moessbauer spectroscopy, an electronic microanalyzer and X-ray diffractometry were used to study the properties of an Au-Fe solid solution during its preparation by installing Fe atoms into the Au matrix by diffusion heating at a temperature from 550 to 850 degC. On the basis of such measurements, the suitable heating temperature was determined at 850 degC; the Debye-Waller factor for Au-Fe is f=0.604+-0.040 and two configurations of Fe atoms in the Au crystal lattice were found. (author)

UV and X-ray spectral lines of Be-like Fe ion for plasma diagnostics

International Nuclear Information System (INIS)

Murakami, Izumi; Kato, Takako; Dubau, J.

1996-04-01

We have calculated X-ray and UV spectra of the Be-like Fe (FeXXIII) ion using collisional-radiative model including all fine-structure transitions among the 2s 2 , 2s2p, 2p 2 , 2snl, and 2pnl levels where n = 3 and 4, adopting data for the collision strengths by Zhang and Sampson (1992) and by Sampson, Goett, and Clark (1984). Some line intensity ratios can be used for the temperature diagnostic. We show 5 ratios in UV region and 9 ratios in X-ray region as functions of electron temperature and density at 0.3keV e e = 1-10 25 cm -3 . The effect of cascade in these line ratios is discussed. (author)

Exchange bias effect in Au-Fe3O4 nanocomposites

International Nuclear Information System (INIS)

Chandra, Sayan; Frey Huls, N A; Phan, M H; Srinath, S; Srikanth, H; Garcia, M A; Lee, Youngmin; Wang, Chao; Sun, Shouheng; 2UB, Universitat de Barcelona, Avenida Diagonal 647, E-08028 Barcelona (Spain))" data-affiliation=" (Departament de Física Fonamental and Institut de Nanociència i Nanotecnologia IN2UB, Universitat de Barcelona, Avenida Diagonal 647, E-08028 Barcelona (Spain))" >Iglesias, Òscar

2014-01-01

We report exchange bias (EB) effect in the Au-Fe 3 O 4 composite nanoparticle system, where one or more Fe 3 O 4 nanoparticles are attached to an Au seed particle forming ‘dimer’ and ‘cluster’ morphologies, with the clusters showing much stronger EB in comparison with the dimers. The EB effect develops due to the presence of stress at the Au-Fe 3 O 4 interface which leads to the generation of highly disordered, anisotropic surface spins in the Fe 3 O 4 particle. The EB effect is lost with the removal of the interfacial stress. Our atomistic Monte Carlo studies are in excellent agreement with the experimental results. These results show a new path towards tuning EB in nanostructures, namely controllably creating interfacial stress, and opens up the possibility of tuning the anisotropic properties of biocompatible nanoparticles via a controllable exchange coupling mechanism. (paper)

Energy partition between the core and the penumbra of Au, La, Fe and Na-ion tracks in liquid argon over the energy interval 1-1000 MeV/amu

International Nuclear Information System (INIS)

Mozumder, A.; Takashima, T.

1995-01-01

Recently an allene-doped liquid argon (LAr) calorimeter has been constructed for measuring energies of relativistic heavy ions. The results obtained were compared with simulations that include quenching and certain other factors. This note presents a calculation which is used as a part of a model for the response of a liquid argon calorimeter to accelerated heavy ions. Scintillator response, particularly those made of organic compounds, can be nonlinear due to regions of high ionization density. It is therefore important to know the partition of deposited energy between the core and the penumbra. Here we calculate this partition for Au, La, Fe and Na-ions in LAr over the energy interval 1-1000 MeV/amu. (orig.)

Effects of Au/Fe and Fe nanoparticles on Serratia bacterial growth and production of biosurfactant

International Nuclear Information System (INIS)

Liu, Jia; Vipulanandan, Cumaraswamy

2013-01-01

The overall objective of this study was to compare the effects of Au/Fe and Fe nanoparticles on the growth and performance of Serratia Jl0300. The nanoparticle effect was quantified not only by the bacterial growth on agar plate after 1 hour interaction with the nanoparticles, but also by its production of a biosurfactant from used vegetable oil. The nanoparticles were prepared using the foam method. The concentrations of the nanoparticles used for the bacterial interaction study were varied from 1 mg/L to 1 g/L. The test results showed that the effect of nanoparticles on the bacterial growth and biosurfactant production varied with nanoparticle type, concentrations, and interaction time with the bacteria. Au/Fe nanoparticles didn't show toxicity to Serratia after short time (1 h) exposure, while during 8 days fermentation Au/Fe nanoparticles inhibited the growth of Serratia as well as the biosurfactant production when the concentration of the nanoparticles was higher than 10 mg/L. Fe nanoparticles showed inhibition effects to bacterial growth both after short time and long time interaction with Serratia, as well as to biosurfactant production when its concentration was higher than 100 mg/L. Based on the trends observed in this study, analytical models have been developed to predict the bacterial growth and biosurfactant production with varying concentrations of nanoparticles. - Highlights: • Modeled the effect of nanoparticles on the bacterial growth and biosurfactant production. • Effects of Au/Fe nonoparticles on Serratia Bacterial Growth and Production of Biosurfactant. • Scanning Electron Micrograph of bacteria-nanoparticles interaction

Effects of Au/Fe and Fe nanoparticles on Serratia bacterial growth and production of biosurfactant

Energy Technology Data Exchange (ETDEWEB)

Liu, Jia; Vipulanandan, Cumaraswamy, E-mail: cvipulanandan@uh.edu

2013-10-15

The overall objective of this study was to compare the effects of Au/Fe and Fe nanoparticles on the growth and performance of Serratia Jl0300. The nanoparticle effect was quantified not only by the bacterial growth on agar plate after 1 hour interaction with the nanoparticles, but also by its production of a biosurfactant from used vegetable oil. The nanoparticles were prepared using the foam method. The concentrations of the nanoparticles used for the bacterial interaction study were varied from 1 mg/L to 1 g/L. The test results showed that the effect of nanoparticles on the bacterial growth and biosurfactant production varied with nanoparticle type, concentrations, and interaction time with the bacteria. Au/Fe nanoparticles didn't show toxicity to Serratia after short time (1 h) exposure, while during 8 days fermentation Au/Fe nanoparticles inhibited the growth of Serratia as well as the biosurfactant production when the concentration of the nanoparticles was higher than 10 mg/L. Fe nanoparticles showed inhibition effects to bacterial growth both after short time and long time interaction with Serratia, as well as to biosurfactant production when its concentration was higher than 100 mg/L. Based on the trends observed in this study, analytical models have been developed to predict the bacterial growth and biosurfactant production with varying concentrations of nanoparticles. - Highlights: • Modeled the effect of nanoparticles on the bacterial growth and biosurfactant production. • Effects of Au/Fe nonoparticles on Serratia Bacterial Growth and Production of Biosurfactant. • Scanning Electron Micrograph of bacteria-nanoparticles interaction.

Inner-shell vacancy production and mean charge states of MeV/u Fe, Co, Ni and Cu ions in Au and Bi solid targets

Energy Technology Data Exchange (ETDEWEB)

Ciortea, C. E-mail: ciortea@tandem.nipne.ro; Dumitriu, Dana; Enescu, Sanda E.; Enulescu, A.; Fluerasu, Daniela; Piticu, I.; Szilagyi, Z.S

2002-06-01

The average charge states of 0.1-1.5 MeV/u Fe, Co, Ni and Cu ions in solid Au and Bi targets have been determined, by estimating the mean numbers of outer-shell spectator vacancies during the K-vacancy decay. The latter quantities were obtained from the yield and energy shifts of the K{alpha}, {beta} X-rays, by comparing with calculations in the independent electron approximation. The reported equilibrium charges, mostly characteristic for the inside of the target, are in fairly agreement with Nikolaev and Dmitriev semi-empirical formula [Phys. Lett. 28A (1968) 277].

Phase transformations in Au(Fe) nano- and microparticles obtained by solid state dewetting of thin Au–Fe bilayer films

International Nuclear Information System (INIS)

Amram, D.; Klinger, L.; Rabkin, E.

2013-01-01

Sub-micrometer-sized particles of Au–Fe alloys were obtained by solid-state dewetting of single-crystalline Au–Fe bilayer films, deposited on c-plane sapphire (α-Al 2 O 3 ) substrates. Depending on the annealing parameters, precipitation of an Fe-rich phase occurred on the side facets of the particles in an interface-limited reaction. Based on the literature values of surface and interface energies in the system, the precipitates were expected to grow inside the Au(Fe) particles, resulting in an (Fe) core–(Au) shell morphology. However, more complex, time-dependent precipitate morphologies were observed, with faceted Fe-rich precipitates attached to the parent faceted Au-rich particles of the same height being dominant at the last stages of the transformation. Our high-resolution transmission electron microscopy observations revealed a nanometric segregation layer of Au on the surface of Fe-rich particles and at their interface with sapphire. This segregation layer modified the surface and interface energies of the Fe-rich particles. A thermodynamic transformation model based on the concept of weighted mean curvature was developed, describing the kinetics of precipitations and morphology evolution of the particles during the dewetting process. Employing the values of surface and interface energies modified by segregation resulted in a good qualitative agreement between theory and experiment

Sputtering of Au induced by single Xe ion impacts

International Nuclear Information System (INIS)

Birtcher, R. C.; Donnelly, S. E.

1999-01-01

Sputtering of Au thin films has been determined for Xe ions with energies between 50 and 600 keV. In-situ transmission electron microscopy was used to observe sputtered Au during deposition on a carbon foil near the specimen. Total reflection and transmission sputtering yields for a 62 nm thick Au thin film were determined by ex-situ measurement of the total amount of Au on the carbon foils. In situ observations show that individual Xe ions eject Au nanoparticles as large as 7 nm in diameter with an average diameter of approximately 3 nm. Particle emission correlates with crater formation due to single ion impacts. Nanoparticle emission contributes significantly to the total sputtering yield for Xe ions in this energy range in either reflection or transmission geometry

Critical current densities and flux creep rate in Co-doped BaFe2As2 with columnar defects introduced by heavy-Ion irradiation

International Nuclear Information System (INIS)

Nakajima, Y.; Tsuchiya, Y.; Taen, T.; Yagyuda, H.; Tamegai, T.; Okayasu, S.; Sasase, M.; Kitamura, H.; Murakami, T.

2010-01-01

We report the formation of columnar defects in Co-doped BaFe 2 As 2 single crystals with different heavy-ion irradiations. The formation of columnar defects by 200 MeV Au ion irradiation is confirmed by transmission electron microscopy and their density is about 40% of the irradiation dose. Magneto-optical imaging and bulk magnetization measurements reveal that the critical current density J c is enhanced in the 200 MeV Au and 800 MeV Xe ion irradiated samples while J c is unchanged in the 200 MeV Ni ion irradiated sample. We also find that vortex creep rates are strongly suppressed by the columnar defects. We compare the effect of heavy-ion irradiation into Co-doped BaFe 2 As 2 and cuprate superconductors.

Uptake of Au(III) Ions by Aluminum Hydroxide and Their Spontaneous Reduction to Elemental Gold (Au(0)).

Science.gov (United States)

Yokoyama; Matsukado; Uchida; Motomura; Watanabe; Izawa

2001-01-01

The behavior of AuCl(4)(-) ions during the formation of aluminum hydroxide at pH 6 was examined. With an increase in NaCl concentration, the content of gold taken up by aluminum hydroxide decreased, suggesting that chloro-hydroxy complexes of Au(III) ion were taken up due to the formation of Al-O-Au bonds. It was found unexpectedly that the Au(III) ions taken up were spontaneously reduced to elemental gold without addition of a specific reducing reagent and then colloidal gold particles were formed. The mechanisms for the uptake of Au(III) ions by aluminum hydroxide and for their spontaneous reduction are discussed. Copyright 2001 Academic Press.

Independency of Fe ions in hemoglobin on immunomagnetic reduction assay

International Nuclear Information System (INIS)

Yang, S.Y.; Lan, C.B.; Chen, C.H.; Horng, H.E.; Hong, Chin-Yih; Yang, H.C.; Lai, Y.K.; Lin, Y.H.; Teng, K.S.

2009-01-01

Immunomagnetic reduction (IMR), which involves measuring the reduction in the ac magnetic susceptibility of magnetic reagents, is due to the association between bio-functionalized magnetic nanoparticles and target bio-molecules. This has been demonstrated for assaying proteins in solutions free of Fe ions, such as serum. In this work, the validity of IMR assay for samples rich in Fe ions like hemoglobin (Hb) is investigated. According to the results, there is no magnetic signal contributed by Fe-ion-rich Hb. Furthermore, the results show a high sensitivity in assaying hemoglobin A1c (HbA1c) by using IMR.

Independency of Fe ions in hemoglobin on immunomagnetic reduction assay

Energy Technology Data Exchange (ETDEWEB)

Yang, S.Y. [MagQu Co. Ltd., Sindian City, Taipei County 231, Taiwan (China); Institute of Electro-optical Science and Technology, National Taiwan Normal University, Taipei 116, Taiwan (China); Lan, C.B.; Chen, C.H. [Institute of Electro-optical Science and Technology, National Taiwan Normal University, Taipei 116, Taiwan (China); Horng, H.E. [Institute of Electro-optical Science and Technology, National Taiwan Normal University, Taipei 116, Taiwan (China)], E-mail: phyfv001@scc.ntnu.edu.tw; Hong, Chin-Yih [Department of Mechanical Engineering, Nan-Kai University of Technology, Nantau County, Taiwan (China)], E-mail: cyhong@nkut.edu.tw; Yang, H.C. [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China)], E-mail: hcyang@phys.ntu.edu.tw; Lai, Y.K. [College of Life Sciences, National Tsing Hua University, Hsinchu City 300, Taiwan (China); Department of Bioresources, Da-Yeh University, Changhua 515, Taiwan (China); Lin, Y.H.; Teng, K.S. [Apex Biotechnology Co. Ltd., Hsinchu City 300, Taiwan (China)

2009-10-15

Immunomagnetic reduction (IMR), which involves measuring the reduction in the ac magnetic susceptibility of magnetic reagents, is due to the association between bio-functionalized magnetic nanoparticles and target bio-molecules. This has been demonstrated for assaying proteins in solutions free of Fe ions, such as serum. In this work, the validity of IMR assay for samples rich in Fe ions like hemoglobin (Hb) is investigated. According to the results, there is no magnetic signal contributed by Fe-ion-rich Hb. Furthermore, the results show a high sensitivity in assaying hemoglobin A1c (HbA1c) by using IMR.

Growth of uniform lath-like α-(Fe,Al)OOH and disc-like α-(Fe,Al)2O3 nanoparticles in a highly alkaline medium

International Nuclear Information System (INIS)

Krehula, Stjepko; Music, Svetozar

2010-01-01

The effects of aluminium (Al 3+ )-dopant on the precipitation of uniform lath-like α-FeOOH particles, the obtention and growth of α-(Fe,Al)OOH and α-(Fe,Al) 2 O 3 solid solutions, particle size and shape were investigated using X-ray powder diffraction, Moessbauer and Fourier transform infrared spectroscopies, field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. Acicular α-FeOOH particles, precipitated in a highly alkaline medium with the addition of tetramethylammonium hydroxide (TMAH), were used as reference material. The influence of Al-dopant was investigated by adding varying amounts of Al 3+ ions to the initial FeCl 3 solution. In the presence of lower concentrations of aluminium ions (up to 11.11 mol%) α-(Fe,Al)OOH as a single phase was formed, whereas higher concentrations led to an additional obtention and growth of α-(Fe,Al) 2 O 3 . Al-for-Fe substitution in the α-FeOOH and α-Fe 2 O 3 structures was confirmed by a decrease in the unit-cell dimensions, a decrease in the hyperfine magnetic field and an increase in the wave number of the infrared absorption bands. The presence of lower concentrations of aluminium ions (up to 11.11 mol%) in the precipitation system did not affect the size and shape of the α-(Fe,Al)OOH particles, whereas higher concentrations influenced a decrease in the length and aspect ratio. In the presence of 42.86 mol% Al 3+ ions fairly uniform disc-shaped α-(Fe,Al) 2 O 3 were formed.

A Au82Si18 liquid metal field-ion emitter for the production of Si ions: fundamental properties and mechanisms

International Nuclear Information System (INIS)

Bischoff, L.; Mair, G.L.R.; Aidinis, C.J.; Londos, C.A.; Akhmadaliev, C.; Ganetsos, Th.

2004-01-01

Focused silicon beams are useful for direct write applications, e.g., lithography on silicon without the undesirable effect of substrate contamination. However, since pure silicon is not amenable to liquid metal ion source (LMIS) manufacture, a suitable alloy containing silicon has to be produced. This paper covers almost all fundamental aspects of a Au 82 Si 18 eutectic, including the most detailed beam mass spectra reported to date of a AuSi source. A finding worthy of note in this investigation, manifested in the behaviour of the ion extraction voltage with temperature, is the abnormal behaviour of the surface tension coefficient of the alloy with temperature. An important deduction from this work, however, concerns the mechanisms responsible for the creation of doubly charged ions: reasons of self-consistency indicate that while Si 2+ is directly field evaporated, Au 2+ must form by the post-ionization of Au + . Finally, two different mechanisms seem to co-exist, as far as the production of cluster ions is concerned. While for cluster ions containing only a few atoms some sort of surface field-ionization mechanism might be responsible for their creation, for larger clusters, a droplet break-up mechanism, possibly by ion capture, seems very likely

Preparation and characterization of flower-like gold nanomaterials and iron oxide/gold composite nanomaterials

International Nuclear Information System (INIS)

Yang Zusing; Lin, Z H; Tang, C-Y; Chang, H-T

2007-01-01

We have successfully synthesized flower-like gold nanomaterials and Fe 3 O 4 /Au composite nanomaterials through the use of wet chemical methods in aqueous solution. In the presence of 0.5 mM citrate, 0.313 mM poly(ethylene glycol), and 109.72 mM sodium acetate (NaOAc), we prepared Au nanoflowers (NFs) having diameters ranging from 300 to 400 nm in aqueous solution after the reduction of Au ions at room temperature for 10 min. In the presence of spherical Fe 3 O 4 nanomaterials, we applied a similar synthetic method to prepare Fe 3 O 4 /Au composite nanomaterials, including nanowires (NWs) that have a length of 1.58 μm and a width of 28.3 nm. We conducted energy-dispersive x-ray analysis, scanning electron microscopy, transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) absorption, and x-ray powder diffraction measurements to characterize the as-prepared flower-like Au nanomaterials and Fe 3 O 4 /Au composite nanomaterials. From time-evolution TEM measurements, we suggested that Au atoms that were bound to the Fe 3 O 4 nanomaterials grew to form Fe 3 O 4 /Au composite nanomaterials. The as-prepared Au NFs absorbed light strongly in the visible-near-infrared (Vis-NIR) region (500-1200 nm). The Fe 3 O 4 /Au composite nanomaterials had electronic conductivities greater than 100 nA at an applied voltage of 20 mV, which induced a temperature increase of 20.5 ± 0.5 deg. C under an alternating magnetic field (62 μT)

Fast decolorization of azo methyl orange via heterogeneous Fenton and Fenton-like reactions using alginate-Fe2+/Fe3+ films as catalysts.

Science.gov (United States)

Quadrado, Rafael F N; Fajardo, André R

2017-12-01

The efficiency of Fenton and Fenton-like processes can be seriously affected by the continuous loss of iron ions and by the formation of solid sludge. Here, alginate (Alg) films were synthesized to stabilize iron ions (Fe 2+ and Fe 3+ ) and to enhance their catalytic activities towards the decolorization of methyl orange via heterogeneous Fenton and Fenton-like processes. Iron ions were ionically bond to the Alg molecules resulting in a three-dimensional network with specific structural and morphological features according to the valence states of iron. Our results demonstrated that both Alg-Fe 2+ and Alg-Fe 3+ films show highlighted catalytic activity for the decolorization of MO and high decolorization rates. Reuse experiments demonstrated that both films could be employed in at least five consecutive decolorization processes without losing their catalytic efficiency or stability. Taken together, our findings reveal that the Alg-Fe 2+ and Alg-Fe 3+ films may be suitable low-cost catalysts in heterogeneous Fenton and Fenton-like processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

LiFePO4 nanoparticles enveloped in freestanding sandwich-like graphitized carbon sheets as enhanced remarkable lithium-ion battery cathode.

Science.gov (United States)

Zhang, Yan; Zhang, Huijuan; Li, Xiao; Xu, Haitao; Wang, Yu

2016-04-15

A novel nanostructure where LiFePO4 nanoparticles are enveloped in sandwich-like carbon sheets as an enhanced cathode in lithium-ion batteries has successfully been synthesized for the first time. Compared to previous carbon-based nanocomposites, the achieved sandwich-like LiFePO4 nanocomposites exhibit totally different architecture, in which LiFePO4 nanoparticles are tightly entrapped between two carbon layers, instead of being anchored on the carbon sheet surfaces. In other words, the achieved sandwich-like LiFePO4 nanocomposite carbon layers are actually freestanding and can be operated and separated from each other. This is a great breakthrough in the design and synthesis of carbon-based functional materials. The obtained sandwich-like LiFePO4 nanocomposites present excellent electrochemical performance, which is rationally ascribed to the superb and unique structure and architecture. Of particular note is that the freestanding sandwich-like LiFePO4 nanocomposites exhibit enhanced cyclability and rate capability. At a high current density of 0.1 A g(-1), a stable specific capacity of approximately 168.5 mAh g(-1) can be delivered over 1000 cycles, and when the charge-discharge rates increase to 0.6, 2, 5 and 10 A g(-1), the specific capacities still survive at 149, 129, 114 and 91 mAh g(-1), respectively. Meanwhile, the sandwiched nanocomposite demonstrates a significantly improved low-temperature electrochemical energy storage performance. With respect to the excellent Li storage performance, and facility and reliability of production, the freestanding sandwich-like LiFePO4 nanocomposites are reasonably believed to have a great potential for multiple electrochemical energy storage applications.

Heterogeneous Fenton-like discoloration of methyl orange using Fe3O4/MWCNTs as catalyst: kinetics and Fenton-like mechanism

Science.gov (United States)

Xu, Huan-Yan; Wang, Yuan; Shi, Tian-Nuo; Zhao, Hang; Tan, Qu; Zhao, Bo-Chao; He, Xiu-Lan; Qi, Shu-Yan

2018-03-01

The kinetics and Fenton-like mechanism are two challenging tasks for heterogeneous Fenton-like catalytic oxidation of organic pollutants. In this study, three kinetic models were used for the kinetic studies of Fe3O4/MWCNTs-H2O2 Fenton-like reaction for MO degradation. The results indicated that this reaction followed the first-order kinetic model. The relationship of reaction rate constant and temperature followed the Arrhenius equation. The activation energy and frequency factor of this system were calculated as 8.2 kJ·mol-1 and 2.72 s-1, respectively. The quantifications of Fe ions dissolution and •OH radicals generation confirmed that the homogeneous and heterogeneous catalyses were involved in Fe3O4/MWCNTs-H2O2 Fenton-like reaction. The reaction rate constant was closely related with Fe ions dissolution and •OH radicals generation. Fe3O4/MWCNTs nanocomposites had typical ferromagnetic property and could be easily separated from solution by an external magnet after being used. Furthermore, Fe3O4/MWCNTs nanocomposites exhibited good stability and recyclability. Finally, the Fenton-like mechanisms on homogeneous and heterogeneous catalyses were described.

Electrochemical Sensing toward Trace As(III Based on Mesoporous MnFe2O4/Au Hybrid Nanospheres Modified Glass Carbon Electrode

Directory of Open Access Journals (Sweden)

Shaofeng Zhou

2016-06-01

Full Text Available Au nanoparticles decorated mesoporous MnFe2O4 nanocrystal clusters (MnFe2O4/Au hybrid nanospheres were used for the electrochemical sensing of As(III by square wave anodic stripping voltammetry (SWASV. Modified on a cheap glass carbon electrode, these MnFe2O4/Au hybrid nanospheres show favorable sensitivity (0.315 μA/ppb and limit of detection (LOD (3.37 ppb toward As(III under the optimized conditions in 0.1 M NaAc-HAc (pH 5.0 by depositing for 150 s at the deposition potential of −0.9 V. No obvious interference from Cd(II and Hg(II was recognized during the detection of As(III. Additionally, the developed electrode displayed good reproducibility, stability, and repeatability, and offered potential practical applicability for electrochemical detection of As(III in real water samples. The present work provides a potential method for the design of new and cheap sensors in the application of electrochemical determination toward trace As(III and other toxic metal ions.

Conjugating folate on superparamagnetic Fe3O4@Au nanoparticles using click chemistry

International Nuclear Information System (INIS)

Shen, Xiaofang; Ge, Zhaoqiang; Pang, Yuehong

2015-01-01

Gold-coated magnetic core@shell nanoparticles, which exhibit magneto-optical properties, not only enhance the chemical stability of core and biocompatibility of surface, but also provide a combination of multimodal imaging and therapeutics. The conjugation of these tiny nanoparticles with specific biomolecules allows researchers to target the desired location. In this paper, superparamagnetic Fe 3 O 4 @Au nanoparticles were synthesized and functionalized with the azide group on the surface by formation of self-assembled monolayers. Folate (FA) molecules, non-immunogenic target ligands for cancer cells, are conjugated with alkyne and then immobilized on the azide-terminated Fe 3 O 4 @Au nanoparticles through copper(I)-catalyzed azide-alkyne cycloaddition (click reaction). Myelogenous leukemia K562 cells were used as a folate receptor (FR) model, which can be targeted and extracted by magnetic field after interaction with the Fe 3 O 4 @Au–FA nanoparticles. - Graphical abstract: Self-assembled azide-terminated group on superparamagnetic Fe 3 O 4 @Au nanoparticles followed by click reaction with alkyne-functionalized folate, allowing the nanoparticles target folate receptor of cancer cells. - Highlights: • Azidoundecanethiol was coated on the superparamagnetic Fe 3 O 4 @Au nanoparticles by forming self-assembled monolayers. • Alkyne-terminated folate was synthesized from a reaction between the amine and the carboxylic acid. • Conjugation of Fe 3 O 4 @Au nanoparticles with folate was made by copper-catalyzed azide-alkyne cycloaddition click chemistry

Size effect on L10 ordering and magnetic properties of chemically synthesized FePt and FePtAu nanoparticles

Science.gov (United States)

Jia, Zhiyong; Kang, Shishou; Shi, Shifan; Nikles, David E.; Harrell, J. W.

2005-05-01

There is growing evidence that FePt nanoparticles become increasingly difficult to chemically order as the size approaches a few nanometers. We have studied the chemical ordering of FePt and FePtAu nanoparticle arrays as a function of particle size. Monodisperse Fe49Pt51 and Fe48Pt44Au8 nanoparticles with a size about 6nm were synthesized by the simultaneous decomposition of iron pentacarbonyl and reduction of platinum acetylacetonate and gold (III) acetate in a mixture of phenyl ether and hexadecylamine (HDA), with 1-adamantanecarboxylic acid and HDA as stabilizers. The nanoparticles were dispersed in toluene, films of the particles were cast onto silicon wafers from the dispersion, and the films were annealed in a tube furnace with flowing Ar +5%H2. The magnetic anisotropy and switching volumes were determined from time- and temperature-dependent coercivity measurements. By comparing with 3-nm FePt and FePtAu nanoparticles of comparable composition, the phase transformation is easier for the larger particles. Under the same annealing conditions, the larger particles have higher anisotropy and order parameter. Additive Au is very effective in enhancing the chemical ordering in both small and large particles, with x-ray diffraction superlattice peaks appearing after annealing at 350°C. Dynamic remnant coercivity measurements and magnetic switching volumes suggest particle aggregation at the higher annealing temperatures in both small and large particles.

Wavelengths of the 3p-3d transitions of the Co- and Fe-like ions: The effects of electron correlation

International Nuclear Information System (INIS)

Chen, Mau Hsiung.

1987-01-01

The experimental observations of the 3p 6 3d 9 2 D - 3p 5 3d 10 2 p transitions of the Co-like ions and 3p 6 3d 8 3 F 4 - 3p 5 3d 9 3 F 3 of the Fe-like ions have recently been extended to highly charged ions of heavy elements up to uranium (Z = 92). A comparison between the observed energies and calculated values from the Dirac-Fock model indicated persistent discrepancies of 3 to 4 eV for all ions. Systematic multiconfiguration Dirac-Fock calculations for these transitions have been carried out with emphases on the effects of electron correlation. The previously found discrepancies theory and experiment have mostly removed after the inclusion of the electron-electron correlation effects in the theoretical calculations. 13 refs

Enhanced rate capability and cycling stability of core/shell structured CoFe{sub 2}O{sub 4}/onion-like C nanocapsules for lithium-ion battery anodes

Energy Technology Data Exchange (ETDEWEB)

Liu, Xianguo, E-mail: liuxianguohugh@gmail.com [School of Materials Science and Engineering, Anhui University of Technology, Maanshan 243002 (China); Wu, Niandu; Cui, Caiyun; Zhou, Pingping [School of Materials Science and Engineering, Anhui University of Technology, Maanshan 243002 (China); Sun, Yuping [Center for Engineering Practice and Innovation Education, Anhui University of Technology, Maanshan 243032 (China)

2015-09-25

Highlights: • Core/shell-structured CoFe{sub 2}O{sub 4}/onion-like carbon nanocapsules have been prepared. • CoFe{sub 2}O{sub 4}/C nanocapsules possess good reversibility even when the current density is up to 4C. • CoFe{sub 2}O{sub 4}/C nanocapsules obtain a discharge capacity of 914.2 mA h g{sup −1} after 500 cycles at 0.1C. - Abstract: In this work, core/shell structured CoFe{sub 2}O{sub 4}/onion-like C nanocapsules have been successfully fabricated by the arc discharge method and air-annealing process and confirmed by X-ray diffraction and high-resolution transmission electron microscopy. The core/shell structure effectively withstands the volume change of CoFe{sub 2}O{sub 4} nanoparticles during the cycling process. Moreover, the onion-like C shells reduce the charge transfer resistance and facilitate electron and ion transport throughout the electrode. As a result, CoFe{sub 2}O{sub 4}/onion-like C nanocapsules exhibit excellent performance as a potential anode material for lithium ion batteries and deliver a reversible capacity of 914.2 mA h g{sup −1} at 0.1C, even after 500 cycles and recover its original capacity when the rate returns from 4C to the initial 0.1C after 120 cycles.

Photoionization of FE3+ Ions

International Nuclear Information System (INIS)

Ovchinnikov, O.; Schlachter, F.

2003-01-01

Photoionization of Fe3+ ions was studied for the first time using synchrotron radiation from the Advanced Light Source (ALS) and the merged-beams technique. Fe3+ ions were successfully produced using ferrocene in an electron cyclotron resonance ion source (ECR). The measured yield of Fe4+ photoions as a function of photon energy revealed the presence of resonances that correspond to excitation of autoionizing states. These resonances are superimposed upon the photoion yield produced by direct photoionization, which is a smooth, slowly decreasing function of energy. The spectra for the photoionization of Fe3+ will be analyzed and compared with theory. The data collected will also serve to test models for the propagation of light through ionized matter.

Preparation and characterization of Fe3O4@Au-C225 composite targeted nanoparticles for MRI of human glioma.

Science.gov (United States)

Ge, Yaoqi; Zhong, Yuejiao; Ji, Guozhong; Lu, Qianling; Dai, Xinyu; Guo, Zhirui; Zhang, Peng; Peng, Gang; Zhang, Kangzhen; Li, Yuntao

2018-01-01

To study the characterization of Fe3O4@Au-C225 composite targeted MNPs. Fe3O4@Au-C225 was prepared by the absorption method. The immunosorbent assay was used to evaluate its absorption efficiency at C225 Fc. ZETA SIZER3000 laser particle size analyzer, ultraviolet photometer and its characteristics were analyzed by VSM. the targeting effect of Fe3O4@Au-C225 composite targeted MNPs on U251 cells in vitro were detected by 7.0 Tesla Micro-MR; and subcutaneous transplanted human glioma in nude mice were performed the targeting effect in vivo after tail vein injection of Fe3O4@Au-C225 composite targeted MNPs by MRI. The self-prepared Fe3O4@Au composite MNPs can adsorb C225 with high efficiency of adsorption so that Fe3O4@Au-C225 composite targeted MNPs were prepared successfully. Fe3O4@Au-C225 composite targeted MNPs favorably targeted human glioma cell line U251 in vitro; Fe3O4@Au-C225 composite targeted MNPs have good targeting ability to xenografted glioma on nude mice in vivo, and can be traced by MRI. The Fe3O4@Au-C225 composite targeted MNPs have the potential to be used as a tracer for glioma in vivo.

Multifunctional Fe3O4/Au core/satellite nanocubes: an efficient chemical synthesis, characterization and functionalization of streptavidin protein.

Science.gov (United States)

Abbas, Mohamed; RamuluTorati, Sri; Kim, CheolGi

2017-02-14

A novel and efficient chemical approach for the synthesis of Fe 3 O 4 /Au core/satellite nanocubes is reported. In a one-pot reaction, metallic Au nanodots were successfully deposited on the polyvinylpyrrolidone (PVP) functionalized Fe 3 O 4 nanocube surface for the fabrication of a core/satellite structure (Fe 3 O 4 /Au) by the reduction of HAuCl 4 using ammonia. Transmission electron microscopy and energy dispersive spectroscopy mapping revealed that small Au nanodots of about 2 nm average size decorated the surface of Fe 3 O 4 nanocubes. X-ray diffraction data was used to confirm the formation of both the phases of a cubic inverse spinel structure for Fe 3 O 4 and a bcc structure for Au in the core/satellite structure of Fe 3 O 4 /Au nanocubes. The magnetic properties of the seed Fe 3 O 4 nanocubes and Fe 3 O 4 /Au core/satellite nanocubes were measured by using a superconducting quantum interference device at 300 K. For biological application purposes, the as-synthesized Fe 3 O 4 /Au core/satellite nanocubes were functionalized by cysteamine followed by successful immobilization of streptavidin protein as confirmed through the fluorescence confocal microscopy images.

A 197Au and 57Fe Moessbauer study of the roasting of refractory gold ores

International Nuclear Information System (INIS)

Wagner, F.E.; Marion, P.

1989-01-01

The transformation of chemically bound gold into metallic gold during industrial scale roasting of an arsenical gold ore concentrate from the Fairview Mine, Eastern Transvaal, has been studied quantitatively by 197 Au Moessbauer spectroscopy. The iron compounds in the concentrate, mainly FeAsS and FeS 2 , and their transformations during roasting have been studied by 57 Fe Moessbauer spectroscopy. The bound gold is found to convert into the metal in parallel to the decomposition of FeAsS and the increase in cyanide leachability. This shows that the refractory character of the ore is caused by the chemical bonding of the gold rather than by the physical inclusion of small, discrete metallic particles in the matrix of FeAsS or FeS 2 . The ratio of the f-factors of gold bound in the FeAsS component of a refractory ore and of metallic gold was determined to be f(Au:FeAsS)/f(Au)=1.48 ± 0.09. (orig.)

Measurement of line overlap for resonant photopumping of transitions in neonlike ions by nickel-like ions

International Nuclear Information System (INIS)

Elliott, S.; Beiersdorfer, P.; Nilsen, J.

1993-01-01

A measurement is made of the 3d-4f transition energies in the Ni-like ions Re 47+ , Ir 49+ , Pt 50+ , Au 51+ , and Bi 55+ and the 2p-4d transition energies in the Ne-like ions Br 25+ , Kr 26+ , Rb 27+ , and Y 29+ using the Livermore electron-beam ion trap. The ions studied are candidates for an x-ray laser scheme based on resonant photopumping which predicts lasing among the 3p-3s transitions in a Ne-like ion. The results of the measurements are compared to multiconfiguration Dirac-Fock calculations and systematic differences are found. The best resonance is found for the Pt-Rb pair at 2512 eV, whose energies differ by 0.4±0.1 eV, that is, by only 160 ppm

Sonochemical synthesis, structure and magnetic properties of air-stable Fe3O4/Au nanoparticles

International Nuclear Information System (INIS)

Wu Wei; He Quanguo; Chen Hong; Tang Jianxin; Nie Libo

2007-01-01

Air-stable nanoparticles of Fe 3 O 4 /Au were prepared via sonolysis of a solution mixture of hydrogen tetrachloroaureate(III) trihydrate (HAuCl 4 ) and (3-aminopropyl)triethoxysilane (APTES)-coated Fe 3 O 4 nanoparticles with further drop-addition of sodium citrate. The Fe 3 O 4 /Au nanoparticles were characterized by x-ray powder diffraction (XRD), ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS) and superconducting quantum interference device (SQUID) magnetometry. Nanoparticles of Fe 3 O 4 /Au obtained under appropriate conditions possess a very high saturation magnetization of about 63 emu g -1 and their average diameter is about 30 nm

Nest-like LiFePO4/C architectures for high performance lithium ion batteries

International Nuclear Information System (INIS)

Deng Honggui; Jin Shuangling; Zhan Liang; Qiao Wenming; Ling Licheng

2012-01-01

Highlights: ► Nest-like LiFePO 4 /C architectures (nest-like LPCs) were synthesized by solvothermal method. ► The microstructures of nest-like LPCs are very stable constructed by many nanosheets. ► The unique structures offer nest-like LPC electrode with high rate performance. ► The reversible capacity of nest-like LPCs electrode is as high as 120 mAh g −1 at 10 C. - Abstract: A novel kind of microsized nest-like LiFePO 4 /C architectures was synthesized by solvothermal method using inexpensive and stable Fe 3+ salt as iron source and ethylene glycol as mediate. A layer of carbon could be coated directly on the surface of LiFePO 4 crystals and the nest-like unique structures offer the cathode materials with high reversible capacity, excellent cycling stability and high rate performance. The reversible capacity can maintain 159 mAh g −1 at 0.1 C and 120 mAh g −1 at 10 C.

Enhanced photoelectrochemical response of plasmonic Au embedded BiVO4/Fe2O3 heterojunction.

Science.gov (United States)

Verma, Anuradha; Srivastav, Anupam; Khan, Saif A; Rani Satsangi, Vibha; Shrivastav, Rohit; Kumar Avasthi, Devesh; Dass, Sahab

2017-06-14

The effect of embedding Au nanoparticles (NPs) in a BiVO 4 /Fe 2 O 3 heterojunction for photoelectrochemical water splitting is studied here for the first time. The present nanostructured heterojunction offers three major advantages over pristine BiVO 4 and Fe 2 O 3 : (i) the formation of a heterojunction between BiVO 4 and Fe 2 O 3 enhances the charge carrier separation and transfer, (ii) the layer of Fe 2 O 3 provides protection to BiVO 4 from photocorrosion and, (iii) the Au NPs possessing surface plasmon resonance (SPR) enhance the photoelectrochemical response by transferring energy to metal oxides by hot electron transfer (HET) and plasmon resonant energy transfer (PRET). The present study reveals that the heterojunction ITO/BiVO 4 /Fe 2 O 3 (with 32% v/v Au solution in both layers) gives the best performance and mitigates the limitations of both pristine Fe 2 O 3 and BiVO 4 . A thirteen-fold increment in applied bias photon-to-current conversion efficiency (ABPE) was observed at 1.24 V vs. RHE under the condition of 1 Sun illumination. Monochromatic incident photon-to-current conversion efficiency (IPCE) measurements indicated that an Au embedded heterojunction is more effective in harvesting visible light in comparison to a heterojunction without Au NPs.

Recommended data on proton-ion collision rate coefficients for Fe X-Fe XV ions

International Nuclear Information System (INIS)

Skobelev, I.; Murakami, I.; Kato, T.

2006-01-01

The proton-ion collisions are important for excitation of some ion levels in a high-temperature low density plasma. In the present work evaluation of data obtained for proton-induced transitions in Fe X - Fe XV ions with the help of different theoretical methods is carried out. It is suggested a simple analytical formula with 7 parameters allowing to describe dependency of proton rate coefficient on proton temperature in an enough wide temperature range. The values of free parameters have been determined by fitting of approximation formula to numerical data and are presented for recommended data together with fitting accuracies. By comparing of proton collision rates with electron ones it is shown that proton impact excitation processes may be important for Fe X, XI, XIII-XV ions. The results obtained can be used for plasma kinetics calculations and for development of spectroscopy methods of plasma diagnostics. (author)

Inner-shell vacancy production and multiple ionization effects in 0.1-1.75 MeV/u Mn, Fe, Co, Ni, Cu + Au, Bi collisions

Energy Technology Data Exchange (ETDEWEB)

Ciortea, C. E-mail: ciortea@tandem.nipne.ro; Piticu, I.; Dumitriu, D.E.; Fluerasu, D.; Enulescu, A.; Szilagyi, S.Z.; Enescu, S.E.; Gugiu, M.M.; Dumitrescu, T.A

2003-05-01

Vacancy production in 0.1-1.75 MeV/u Mn, Fe, Co, Ni, Cu + Au, Bi collisions has been studied by measuring integral inner-shell ionization cross-sections and mean outer-shell ionization probabilities at the Tandem accelerator of NIPNE, Bucharest. X-ray spectra induced by ion beams of Mn, Fe, Co, Ni and Cu impinging on thin solid-foil targets of Au and Bi have been measured. Total ionization cross-sections for the K-shell of the projectile and L{sub 3}-subshell of the target, as well as vacancy sharing probabilities, corrected for the effect of multiple ionization, are reported. The experimental results are discussed in terms of two model calculations.

Dielectronic Recombination of Al-Like Ions

Science.gov (United States)

Abdel-Naby, Shahin; Nikolic, Dragan; Gorczyca, Thomas W.; Badnell, Nigel R.; Savin, Daniel W.

2008-05-01

Accurate dielectronic recombination (DR) data are important for cosmic and laboratory plasma modeling. Over the past few years, our group has computed reliable DR data for all isoelectronic sequences up through Mg-like ions. Recently, we have focused our work on the complex third-row M-shell isoelectronic sequences, especially Al-like. Previous calculations for the DR rate coefficient for S^3+ were performed only within a non-relativistic LS-coupling approximation. Fe^13+ DR calculations, including semi-relativistic effects, have been completed and tested against the Heidelberg heavy-ion Test Storage Ring facility measurements. Here we present semi-relativistic DR rate coefficient calculations for a wide range of Al-like ions using AUTOSTRUCTURE, a level-resolved distorted-wave program package. The important effect of fine structure splitting in the Al-like ground state will be discussed. Finally, our results are fitted into a simple formula for use by astrophysical plasma modelers.This work was funded in part by NASA (APRA), NASA (SHP) SR&T, and UK PPARC grants.

Magnetic Fe{sub 3}O{sub 4}-Au core-shell nanostructures for surface enhanced Raman scattering

Energy Technology Data Exchange (ETDEWEB)

Wheeler, D.A.; Adams, S.A.; Zhang, J.Z. [Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064 (United States); Lopez-Luke, T. [Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064 (United States); Cento de Investigaciones en Optica, A.P. 1-948 Leon, Gto. 37150 (Mexico); Torres-Castro, A. [Universidad Autonoma de Nuevo Leon, A.P. 126-F, Monterrey, NL, 66450 (Mexico)

2012-11-15

The synthesis, structural and optical characterization, and application of superparamagnetic and water-dispersed Fe{sub 3}O{sub 4}-Au core-shell nanoparticles for surface enhanced Raman scattering (SERS) is reported. The structure of the nanoparticles was determined by scanning transmission electron microscopy (STEM) and high-resolution transmission electron microscopy (HRTEM). STEM images of the Fe{sub 3}O{sub 4}-Au core-shell nanoparticles reveal an average diameter of 120 nm and a high degree of surface roughness. The nanoparticles, which display superparamagnetic properties due to the core Fe{sub 3}O{sub 4} material, exhibit a visible surface plasmon resonance (SPR) peaked at 580 nm due to the outer gold shell. The nanoparticles are used as a substrate for surface enhanced Raman scattering (SERS) with rhodamine 6G (R6G) as a Raman reporter molecule. The SERS enhancement factor is estimated to be on the order of 10{sup 6}, which is {proportional_to} 2 times larger than that of conventional gold nanoparticles (AuNPs) under similar conditions. Significantly, magnetically-induced aggregation of the Fe{sub 3}O{sub 4}-Au core-shell nanoparticles substantially enhanced SERS activity compared to non-magnetically-aggregated Fe{sub 3}O{sub 4}-Au nanoparticles. This is attributed to both increased scattering from the aggregates as well as ''hot spots'' due to more junction sites in the magnetically-induced aggregates. The magnetic properties of the Fe{sub 3}O{sub 4} core, coupled with the optical properties of the Au shell, make the Fe{sub 3}O{sub 4}-Au nanoparticles unique for various potential applications including biological sensing and therapy. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Immobilizing LaFeO_3 nanoparticles on carbon spheres for enhanced heterogeneous photo-Fenton like performance

International Nuclear Information System (INIS)

Wang, Kaixuan; Niu, Helin; Chen, Jingshuai; Song, Jiming; Mao, Changjie; Zhang, Shengyi; Gao, Yuanhao

2017-01-01

Highlights: • LaFeO_3 nanoparticles sub–10 nm were successfully immobilized on monodisperse carbon spheres for the first time through a facile and environmental friendly ultrasonic assisted surface ions adsorption method. • LaFeO_3/C nanocomposite exhibits much higher photo-Fenton like catalytic activity than LaFeO_3. • The superior property was attributed to the synergistic effects from the photo-Fenton like process and the presence of monodisperse carbon spheres. - Abstract: LaFeO_3 nanoparticles immobilized on the surface of monodisperse carbon spheres have been obtained through a facile and environmentally friendly ultrasonic assisted surface ions adsorption method. The LaFeO_3/C nanocomposite was evaluated as photo-Fenton like catalyst for the degradation of Rhodamine B (RhB) under visible light irradiation (λ > 420 nm). The LaFeO_3/C nanocomposite possesses high specific surface area compared with pure LaFeO_3 and significantly enhanced photo-Fenton like catalytic performance. The possible formation process of the LaFeO_3/C nanocomposite and the mechanism for photo-Fenton like reaction were discussed. The superior property was attributed to the synergistic effects from the photo-Fenton like process and the presence of carbon spheres. In addition, the heterogeneous process led to better recyclability of this type of catalyst.

Formation of multifunctional Fe3O4/Au composite nanoparticles for dual-mode MR/CT imaging applications

International Nuclear Information System (INIS)

Hu Yong; Li Jing-Chao; Shen Ming-Wu; Shi Xiang-Yang

2014-01-01

Recent advances with iron oxide/gold (Fe 3 O 4 /Au) composite nanoparticles (CNPs) in dual-modality magnetic resonance (MR) and computed tomography (CT) imaging applications are reviewed. The synthesis and assembly of “dumbbelllike” and “core/shell” Fe 3 O 4 /Au CNPs is introduced. Potential applications of some developed Fe 3 O 4 /Au CNPs as contrast agents for dual-mode MR/CT imaging applications are described in detail. (topical review - magnetism, magnetic materials, and interdisciplinary research)

Recent advances in the synthesis of Fe3O4@AU core/shell nanoparticles

International Nuclear Information System (INIS)

Salihov, Sergei V.; Ivanenkov, Yan A.; Krechetov, Sergei P.; Veselov, Mark S.; Sviridenkova, Natalia V.; Savchenko, Alexander G.; Klyachko, Natalya L.; Golovin, Yury I.; Chufarova, Nina V.; Beloglazkina, Elena K.; Majouga, Alexander G.

2015-01-01

Fe 3 O 4 @Au core/shell nanoparticles have unique magnetic and optical properties. These nanoparticles are used for biomedical applications, such as magnetic resonance imaging, photothermal therapy, controlled drug delivery, protein separation, biosensors, DNA detection, and immunosensors. In this review, recent methods for the synthesis of core/shell nanoparticles are discussed. We divided all of the synthetic methods in two groups: methods of synthesis of bi-layer structures and methods of synthesis of multilayer composite structures. The latter methods have a layer of “glue” material between the core and the shell. - Highlights: • Fe 3 O 4 nanoparticles are promising for biomedical applications but have some disadvantages. • Covering Fe 3 O 4 nanoparticles with Au shell leads to better stability and biocompatibility. • Core/shell nanoparticles are widely used for biomedical applications. • There are two types of Fe 3 O 4 @Au core/shell nanoparticles structures: bi-layer and multilayer composite. • Different synthetic methods enable production of nanoparticles of different sizes

Controlled synthesis of PbS-Au nanostar-nanoparticle heterodimers and cap-like Au nanoparticles

Science.gov (United States)

Zhao, Nana; Li, Lianshan; Huang, Teng; Qi, Limin

2010-11-01

Uniform PbS-Au nanostar-nanoparticle heterodimers consisting of one Au nanoparticle grown on one horn of a well-defined six-horn PbS nanostar were prepared using the PbS nanostars as growth substrates for the selective deposition of Au nanoparticles. The size of the Au nanoparticles on the horns of the PbS nanostars could be readily adjusted by changing the PbS concentration for the deposition of Au nanoparticles. An optimum cetyltrimethylammonium bromide concentration and temperature were essential for the selective deposition of uniform Au nanoparticles on single horns of the PbS nanostars. Unusual PbS-Au nanoframe-nanoparticle heterodimers were obtained by etching the PbS-Au nanostar-nanoparticle heterodimers with oxalic acid while novel cap-like Au nanoparticles were obtained by etching with hydrochloric acid. The obtained heterodimeric nanostructures and cap-like nanoparticles are promising candidates for anisotropic nanoscale building blocks for the controllable assembly of useful, complex architectures.

Positron transport studies at the Au - (InP:Fe) interface

Science.gov (United States)

Au, H. L.; Lee, T. C.; Beling, C. D.; Fung, S.

1996-03-01

Positron mobility and lifetime measurements have been carried out on semi-insulating Fe-doped InP samples with Au contacts used for electric field application. The lifetime measurements, with electric fields directed towards the Au - InP:Fe interface, reveal no component associated with interfacial open-volume sites and thus give no evidence of any positron mobility. The mobility measurements, made using the Doppler-shifted annihilation radiation technique, however, reveal a temperature independent positron mobility of about 0953-8984/8/10/012/img1 in the range 150 - 300 K. These observations, together with results from I - V analysis, are discussed with reference to two possible band-bending schemes. The first, which requires an ionized shallow donor region adjacent to the Au - InP interface, seems less plausible on a number of grounds. In the second, however, an 0953-8984/8/10/012/img2 negative space charge produces an adverse diffusion barrier for positrons approaching the interface together with a non-uniform electric field in the samples capable of explaining the observed mobility results.

Comparison of electrochemical performances of olivine NaFePO4 in sodium-ion batteries and olivine LiFePO4 in lithium-ion batteries.

Science.gov (United States)

Zhu, Yujie; Xu, Yunhua; Liu, Yihang; Luo, Chao; Wang, Chunsheng

2013-01-21

Carbon-coated olivine NaFePO(4) (C-NaFePO(4)) spherical particles with a uniform diameter of ∼80 nm are obtained by chemical delithiation and subsequent electrochemical sodiation of carbon-coated olivine LiFePO(4) (C-LiFePO(4)), which is synthesized by a solvothermal method. The C-NaFePO(4) electrodes are identical (particle size, particle size distribution, surface coating, and active material loading, etc.) to C-LiFePO(4) except that Li ions in C-LiFePO(4) are replaced by Na ions, making them ideal for comparison of thermodynamics and kinetics between C-NaFePO(4) cathode in sodium-ion (Na-ion) batteries and C-LiFePO(4) in lithium-ion (Li-ion) batteries. In this paper, the equilibrium potentials, reaction resistances, and diffusion coefficient of Na in C-NaFePO(4) are systematically investigated by using the galvanostatic intermittent titration technique (GITT), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), and compared to those of the well-known LiFePO(4) cathodes in Li-ion batteries. Due to the lower diffusion coefficient of Na-ion and higher contact and charge transfer resistances in NaFePO(4) cathodes, the rate performance of C-NaFePO(4) in Na-ion batteries is much worse than that of C-LiFePO(4) in Li-ion batteries. However, the cycling stability of C-NaFePO(4) is almost comparable to C-LiFePO(4) by retaining 90% of its capacity even after 100 charge-discharge cycles at a charge-discharge rate of 0.1 C.

Quantum electrodynamics effects in the 4s-4p transitions in Cu-like and Zn-like ions

International Nuclear Information System (INIS)

Cheng, K.; Wagner, R.A.

1987-01-01

Multiconfiguration Dirac-Fock energies are compared with experiment for the 4s-4p transitions in Cu-like ions and the 4s 2 1 S 0 --4s4p 1 P 1 transition in Zn-like ions for Au, Pb, Bi, Th, and U. The Coulomb, Breit, and QED contributions to these transitions are tabulated for selected ions in the range Z = 50--92. Results show that the agreement between theory and experiment is good enough to show the importance of QED corrections in the spectra of these highly stripped ions. Contrary to earlier findings by Seely et al. [Phys. Rev. Lett. 57, 2924 (1986)] we find no significant differences between the observed and calculated transition energies after finite-nuclear-size corrections are included

Fe3O4@Au composite magnetic nanoparticles modified with cetuximab for targeted magneto-photothermal therapy of glioma cells.

Science.gov (United States)

Lu, Qianling; Dai, Xinyu; Zhang, Peng; Tan, Xiao; Zhong, Yuejiao; Yao, Cheng; Song, Mei; Song, Guili; Zhang, Zhenghai; Peng, Gang; Guo, Zhirui; Ge, Yaoqi; Zhang, Kangzhen; Li, Yuntao

2018-01-01

Thermoresponsive nanoparticles have become an attractive candidate for designing combined multimodal therapy strategies because of the onset of hyperthermia and their advantages in synergistic cancer treatment. In this paper, novel cetuximab (C225)-encapsulated core-shell Fe 3 O 4 @Au magnetic nanoparticles (Fe 3 O 4 @Au-C225 composite-targeted MNPs) were created and applied as a therapeutic nanocarrier to conduct targeted magneto-photothermal therapy against glioma cells. The core-shell Fe 3 O 4 @Au magnetic nanoparticles (MNPs) were prepared, and then C225 was further absorbed to synthesize Fe 3 O 4 @Au-C225 composite-targeted MNPs. Their morphology, mean particle size, zeta potential, optical property, magnetic property and thermal dynamic profiles were characterized. After that, the glioma-destructive effect of magnetic fluid hyperthermia (MFH) combined with near-infrared (NIR) hyperthermia mediated by Fe 3 O 4 @Au-C225 composite-targeted MNPs was evaluated through in vitro and in vivo experiments. The inhibitory and apoptotic rates of Fe 3 O 4 @Au-C225 composite-targeted MNPs-mediated combined hyperthermia (MFH+NIR) group were significantly higher than other groups in vitro and the marked upregulation of caspase-3, caspase-8, and caspase-9 expression indicated excellent antitumor effect by inducing intrinsic apoptosis. Furthermore, Fe 3 O 4 @Au-C225 composite-targeted MNPs-mediated combined hyperthermia (MFH+NIR) group exhibited significant tumor growth suppression compared with other groups in vivo. Our studies illustrated that Fe 3 O 4 @Au-C225 composite-targeted MNPs have great potential as a promising nanoplatform for human glioma therapy and could be of great value in medical use in the future.

Coexistence of plasmonic and magnetic properties in Au89Fe 11 nanoalloys

KAUST Repository

Amendola, Vincenzo; Meneghetti, Moreno; Bakr, Osman; Riello, Pietro; Polizzi, Stefano; Anjum, Dalaver H.; Fiameni, Stefania; Arosio, Paolo; Orlando, Tomas; De Julian Fernandez, Cé sar; Pineider, Francesco; Sangregorio, Claudio; Lascialfari, Alessandro

2013-01-01

We describe an environmentally friendly, top-down approach to the synthesis of Au89Fe11 nanoparticles (NPs). The plasmonic response of the gold moiety and the magnetism of the iron moiety coexist in the Au 89Fe11 nanoalloy with strong modification compared to single element NPs, revealing a non-linear surface plasmon resonance dependence on the iron fraction and a transition from paramagnetic to a spin-glass state at low temperature. These nanoalloys are accessible to conjugation with thiolated molecules and they are promising contrast agents for magnetic resonance imaging. © 2013 The Royal Society of Chemistry.

Controllable synthesis and characterization of Fe3O4/Au composite nanoparticles

International Nuclear Information System (INIS)

Xing, Yan; Jin, Yan-Yan; Si, Jian-Chao; Peng, Ming-Li; Wang, Xiao-Fang; Chen, Chao; Cui, Ya-Li

2015-01-01

Fe 3 O 4 /Au composite nanoparticles (GoldMag NPs) have received considerable attention because of their advantageous properties arisen from both individual Au and Fe 3 O 4 nanoparticles. Many efforts have been devoted to the synthesis of these composite nanoparticles. Herein, GoldMag NPs were reported to be synthesized by two-step method. Fe 3 O 4 nanoparticles were prepared by co-precipitation and modified by the citric acid, and then citric acid-coated Fe 3 O 4 nanoparticles were used as seeds in sodium citrate solution to reduce the HAuCl 4 . The size of obtained nanoparticles was geared from 25 to 300 nm by controlling the concentration of reactants. The GoldMag NPs were characterized by UV–vis spectrometer, dynamic light scattering (DLS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The GoldMag NPs showed good superparamagnetism at room temperature and were well dispersed in water with surface plasmon resonance absorption peak varied from 538 nm to 570 nm. - Highlights: • A low cost, simple manipulation and nontoxic approach was designed for preparation of magnetic Fe 3 O 4 /Au (GoldMag NPs) nanocomposites. • The size of GoldMag NPs could be controlled from 25 to 300 nm by varying the concentration of reactants. • GoldMag NPs possessed good magnetic response, high dispersion, and good stability

Highly Stable [C60AuC60]+/- Dumbbells.

Science.gov (United States)

Goulart, Marcelo; Kuhn, Martin; Martini, Paul; Chen, Lei; Hagelberg, Frank; Kaiser, Alexander; Scheier, Paul; Ellis, Andrew M

2018-05-17

Ionic complexes between gold and C 60 have been observed for the first time. Cations and anions of the type [Au(C 60 ) 2 ] +/- are shown to have particular stability. Calculations suggest that these ions adopt a C 60 -Au-C 60 sandwich-like (dumbbell) structure, which is reminiscent of [XAuX] +/- ions previously observed for much smaller ligands. The [Au(C 60 ) 2 ] +/- ions can be regarded as Au(I) complexes, regardless of whether the net charge is positive or negative, but in both cases, the charge transfer between the Au and C 60 is incomplete, most likely because of a covalent contribution to the Au-C 60 binding. The C 60 -Au-C 60 dumbbell structure represents a new architecture in fullerene chemistry that might be replicable in synthetic nanostructures.

Immobilizing LaFeO{sub 3} nanoparticles on carbon spheres for enhanced heterogeneous photo-Fenton like performance

Energy Technology Data Exchange (ETDEWEB)

Wang, Kaixuan [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230601 (China); Niu, Helin, E-mail: niuhelin@ahu.edu.cn [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230601 (China); Chen, Jingshuai; Song, Jiming; Mao, Changjie; Zhang, Shengyi [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230601 (China); Gao, Yuanhao [Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000 (China)

2017-05-15

Highlights: • LaFeO{sub 3} nanoparticles sub–10 nm were successfully immobilized on monodisperse carbon spheres for the first time through a facile and environmental friendly ultrasonic assisted surface ions adsorption method. • LaFeO{sub 3}/C nanocomposite exhibits much higher photo-Fenton like catalytic activity than LaFeO{sub 3}. • The superior property was attributed to the synergistic effects from the photo-Fenton like process and the presence of monodisperse carbon spheres. - Abstract: LaFeO{sub 3} nanoparticles immobilized on the surface of monodisperse carbon spheres have been obtained through a facile and environmentally friendly ultrasonic assisted surface ions adsorption method. The LaFeO{sub 3}/C nanocomposite was evaluated as photo-Fenton like catalyst for the degradation of Rhodamine B (RhB) under visible light irradiation (λ > 420 nm). The LaFeO{sub 3}/C nanocomposite possesses high specific surface area compared with pure LaFeO{sub 3} and significantly enhanced photo-Fenton like catalytic performance. The possible formation process of the LaFeO{sub 3}/C nanocomposite and the mechanism for photo-Fenton like reaction were discussed. The superior property was attributed to the synergistic effects from the photo-Fenton like process and the presence of carbon spheres. In addition, the heterogeneous process led to better recyclability of this type of catalyst.

Ammonia synthesis on Au modified Fe(111) and Ag and Cu modified Fe(100) surfaces

DEFF Research Database (Denmark)

Lytken, Ole; Waltenburg, Hanne Neergaard; Chorkendorff, Ib

2003-01-01

In order to investigate any influence of steps and possible positive effects of making surface alloys the ammonia synthesis has been investigated over Au modified Fe(111) and Ag and Cu modified Fe(100) single crystals in the temperature range 603-773 K, using a system combining ultra-high vacuum...... and a high-pressure cell. Ammonia was synthesized from a stoichiometric (N-2:3H(2)) gas mixture at a pressure of 2 bar. By deposition of small amounts of An, the ammonia production activity of the Fe(1 1 1) surface can be enhanced. More important, for the gold modified surface, the reaction order in ammonia...

Fe doped Magnetic Nanodiamonds made by Ion Implantation.

Science.gov (United States)

Chen, ChienHsu; Cho, I C; Jian, Hui-Shan; Niu, H

2017-02-09

Here we present a simple physical method to prepare magnetic nanodiamonds (NDs) using high dose Fe ion-implantation. The Fe atoms are embedded into NDs through Fe ion-implantation and the crystal structure of NDs are recovered by thermal annealing. The results of TEM and Raman examinations indicated the crystal structure of the Fe implanted NDs is recovered completely. The SQUID-VSM measurement shows the Fe-NDs possess room temperature ferromagnetism. That means the Fe atoms are distributed inside the NDs without affecting NDs crystal structure, so the NDs can preserve the original physical and chemical properties of the NDs. In addition, the ion-implantation-introduced magnetic property might make the NDs to become suitable for variety of medical applications.

Fe doped Magnetic Nanodiamonds made by Ion Implantation

Science.gov (United States)

Chen, Chienhsu; Cho, I. C.; Jian, Hui-Shan; Niu, H.

2017-02-01

Here we present a simple physical method to prepare magnetic nanodiamonds (NDs) using high dose Fe ion-implantation. The Fe atoms are embedded into NDs through Fe ion-implantation and the crystal structure of NDs are recovered by thermal annealing. The results of TEM and Raman examinations indicated the crystal structure of the Fe implanted NDs is recovered completely. The SQUID-VSM measurement shows the Fe-NDs possess room temperature ferromagnetism. That means the Fe atoms are distributed inside the NDs without affecting NDs crystal structure, so the NDs can preserve the original physical and chemical properties of the NDs. In addition, the ion-implantation-introduced magnetic property might make the NDs to become suitable for variety of medical applications.

The nonenzyme ethanol sensor based on pt nps and fe/sub 3/O/sub 4/ mnps modified au electrode

International Nuclear Information System (INIS)

Wan, J.; Ma, X.; Yin, G.

2013-01-01

The none enzyme ethanol sensor was prepared using Pt nanoparticles (NPs) and Fe/sub 3/O/sub 4/ magnetic nanoparticles (MNPs) modified Au electrode. Pt NPs were deposited on the gold plated electrode through the method of potentiostatic deposition. Fe/sub 3/O/sub 4/ magnetic nanoparticles were added to the surface of Pt NPs modified Au electrode to obtain the Au/Pt/ Fe/sub 3/O/sub 4/ MNPs electrode. The as-prepared Au/Pt/Fe/sub 3/O/sub 4/ MNPs electrode was used for the detection of liquid ethanol without using enzyme. Cyclic voltammetry and differential pulse voltammetry were used to study the behavior of ethanol electro-catalytic oxidation on Pt/Au/Fe/sub 3/O/sub 4/ electrode. It was found that Pt NPs played strong catalytic oxidation role of ethanol with the presence of Fe/sub 3/O/sub 4/ MNPs. The linear range of Au/Pt/Fe/sub 3/O/sub 4/ MNPs electrode for the detection of ethanol was of 2 x 10 /sup -5/ 1.1 x 10/sup -4/ mol L/sup -1/ and the detection limit was of 3.2 x 10/sup -6/ mol L/sup -5/ when signal to noise ratio was 3sigma. The sensibility of the sensor is 420.4 microA mmol/sup -1/ /sup -2cm/. The simple method provided an effective means for fabricating the novel sensors. (author)

Spin glass transition in canonical AuFe alloys: A numerical study

International Nuclear Information System (INIS)

Zhang, Kai-Cheng; Li, Yong-Feng; Liu, Gui-Bin; Zhu, Yan

2012-01-01

Although spin glass transitions have long been observed in diluted magnetic alloys, e.g. AuFe and CuMn alloys, previous numerical studies are not completely consistent with the experiment results. The abnormal critical exponents of the alloys remain still puzzling. By employing parallel tempering algorithm with finite-size scaling analysis, we investigated the phase transitions in canonical AuFe alloys. Our results strongly support that spin glass transitions occur at finite temperatures in the alloys. The calculated critical exponents agree well with those obtained from experiments. -- Highlights: ► By simulation we investigated the abnormal critical exponents observed in canonical SG alloys. ► The critical exponents obtained from our simulations agree well with those measured from experiments. ► Our results strongly support that RKKY interactions lead to SG transitions at finite temperatures.

A novel platform of hemoglobin on core-shell structurally Fe{sub 3}O{sub 4}-Au nanoparticles and its direct electrochemistry

Energy Technology Data Exchange (ETDEWEB)

Liu Yang; Han Ting; Chen Chao; Bao Ning; Yu Chunmei [Institute of Analytical Chemistry for Life Science, School of Public Health, Nantong University, Nantong 226019 (China); Gu Haiying, E-mail: hygu@ntu.edu.c [Institute of Analytical Chemistry for Life Science, School of Public Health, Nantong University, Nantong 226019 (China)

2011-03-30

Research highlights: {yields} In recent years, immobilization of biomolecule onto nanomaterials, which could be utilized in the investigation of biomolecule reactions and the preparations of the biosensors, has attracted much research attention. A novel platform, which hemoglobin (Hb) was immobilized on core-shell structurally Fe{sub 3}O{sub 4}/Au nanoparticles (simplified as Fe{sub 3}O{sub 4}-Au NPs) modified glassy carbon electrode (GCE), has been developed for fabricating the third biosensors in this paper. {yields} Magnetic NPs stand out because of their added properties. However, naked Fe{sub 3}O{sub 4} NPs are very sensitive to oxidation because of their high chemical reactivity and being prone to aggregate. Those defects limit their further applications. We presented a simple approach to synthesize Au modified Fe{sub 3}O{sub 4} NPs with core-shell structure, which was characterized by transmission electron microscopy, scanning electron microscope, energy dispersive spectra and UV-vis spectroscopy. {yields} The thermodynamics, dynamics and catalysis properties of Hb immobilized on Fe{sub 3}O{sub 4}-Au NPs were discussed by UV-visible spectrum, electrochemical impedance spectroscopy, electrochemical quartz crystal microbalance technique and cyclic voltammetry. The electrocatalytic behaviors of the immobilized Hb on Fe{sub 3}O{sub 4}-Au NPs were applied for the determination of hydrogen peroxide, oxygen and trichloroacetic acid. The possible functions of Fe{sub 3}O{sub 4} core and Au shell as a novel platform for achieving Hb direct electrochemistry were also discussed, respectively. - Abstract: A novel platform, which hemoglobin (Hb) was immobilized on core-shell structurally Fe{sub 3}O{sub 4}/Au nanoparticles (simplified as Fe{sub 3}O{sub 4}-Au NPs) modified glassy carbon electrode (GCE), has been developed for fabricating the third biosensors. Fe{sub 3}O{sub 4}-Au NPs, characterized using transmission electron microscope (TEM), scanning electron microscope

Synthesizing single-phase β-FeSi2 via ion beam irradiations of Fe/Si bilayers

International Nuclear Information System (INIS)

Milosavljevic, M.; Dhar, S.; Schaaf, P.; Bibic, N.; Lieb, K.P.

2001-01-01

This paper presents results on the direct synthesis of the β-FeSi 2 phase by ion beam mixing of Fe/Si bilayers with Xe ions. The influence of the substrate temperature, ion fluence and energy on the growth of this phase was investigated using Rutherford backscattering (RBS), X-ray diffraction (XRD) and conversion electron Moessbauer spectroscopy (CEMS). Complete growth of single-phase β-FeSi 2 was achieved by 205 keV Xe ion irradiation to a fluence of 2x10 16 ions/cm 2 at 600 deg. C. We propose a two-step reaction mechanism involving thermal and ion beam energy deposition

Radioiodination of cyclin dependent kinase inhibitor Olomoucine loaded Fe rate at Au nanoparticle and evaluation of the therapeutic efficacy on cancerous cells

Energy Technology Data Exchange (ETDEWEB)

Takan, Gokhan; Guldu, Ozge Kozgus; Medine, Emin Ilker [Ege Univ., Izmir (Turkey). Dept. of Nuclear Applications

2017-06-01

Magnetic nanoparticles have promising biomedical applications such as drug delivery, novel therapeutics and diagnostic imaging. Magnetic drug delivery combination works on the delivery of magnetic nanoparticles loaded with drug to the target tissue by means of an external magnetic field. Gold coated iron oxide (Fe rate at Au) nanoparticles can provide useful surface chemistry and biological reactivity. Covalent conjugation to the Fe rate at Au nanoparticles through cleavable linkages can be used to deliver drugs to tumor cells, then the drug can be released by an external. In this paper, purine based cyclin dependent kinases (CDKs) inhibitor Olomoucine (Olo) [2-(Hydroxyethylamino)-6-benzylamino-9-methylpurine] was loaded on gold coated iron oxide (Fe rate at Au) nanoparticles and radiolabeled with {sup 131}I to combine magnetic targeted drug delivery and radiotherapy. Fe rate at Au nanoparticles were synthesized by microemulsion method. The characterization of nanoparticles was examined by TEM, VSM and XRD. Amine activation was utilized by cysteamine hydrochloride and then CDI was used for conjugation of Olomoucine. Antiproliferative effect and cytotoxicity of Olomoucine loaded Fe rate at Au nanoparticles (Fe rate at Au-Olo) were investigated on MCF7 and A549 cell lines. Proliferation rate was decreased while uptake of Fe rate at Au-Olo on both cell lines was high in comparison with Olomoucine. Also, enhanced incorporation ratio was observed under external magnetic field.

Radioiodination of cyclin dependent kinase inhibitor Olomoucine loaded Fe rate at Au nanoparticle and evaluation of the therapeutic efficacy on cancerous cells

International Nuclear Information System (INIS)

Takan, Gokhan; Guldu, Ozge Kozgus; Medine, Emin Ilker

2017-01-01

Magnetic nanoparticles have promising biomedical applications such as drug delivery, novel therapeutics and diagnostic imaging. Magnetic drug delivery combination works on the delivery of magnetic nanoparticles loaded with drug to the target tissue by means of an external magnetic field. Gold coated iron oxide (Fe rate at Au) nanoparticles can provide useful surface chemistry and biological reactivity. Covalent conjugation to the Fe rate at Au nanoparticles through cleavable linkages can be used to deliver drugs to tumor cells, then the drug can be released by an external. In this paper, purine based cyclin dependent kinases (CDKs) inhibitor Olomoucine (Olo) [2-(Hydroxyethylamino)-6-benzylamino-9-methylpurine] was loaded on gold coated iron oxide (Fe rate at Au) nanoparticles and radiolabeled with "1"3"1I to combine magnetic targeted drug delivery and radiotherapy. Fe rate at Au nanoparticles were synthesized by microemulsion method. The characterization of nanoparticles was examined by TEM, VSM and XRD. Amine activation was utilized by cysteamine hydrochloride and then CDI was used for conjugation of Olomoucine. Antiproliferative effect and cytotoxicity of Olomoucine loaded Fe rate at Au nanoparticles (Fe rate at Au-Olo) were investigated on MCF7 and A549 cell lines. Proliferation rate was decreased while uptake of Fe rate at Au-Olo on both cell lines was high in comparison with Olomoucine. Also, enhanced incorporation ratio was observed under external magnetic field.

INTERPLANETARY PROPAGATION OF SOLAR ENERGETIC PARTICLE HEAVY IONS OBSERVED AT 1 AU AND THE ROLE OF ENERGY SCALING

International Nuclear Information System (INIS)

Mason, G. M.; Haggerty, D. K.; Li, G.; Zank, G. P.; Cohen, C. M. S.; Leske, R. A.; Mewaldt, R. A.; Desai, M. I.

2012-01-01

We have studied ∼0.3 to >100 MeV nucleon –1 H, He, O, and Fe in 17 large western hemisphere solar energetic particle events (SEP) to examine whether the often observed decrease of Fe/O during the rise phase is due to mixing of separate SEP particle populations, or is an interplanetary transport effect. Our earlier study showed that the decrease in Fe/O nearly disappeared if Fe and O were compared at energies where the two species interplanetary diffusion coefficient were equal, and therefore their kinetic energy nucleon –1 was different by typically a factor ∼2 ( e nergy scaling ) . Using an interplanetary transport model that includes effects of focusing, convection, adiabatic deceleration, and pitch angle scattering we have fit the particle spectral forms and intensity profiles over a broad range of conditions where the 1 AU intensities were reasonably well connected to the source and not obviously dominated by local shock effects. The transport parameters we derive are similar to earlier studies. Our model follows individual particles with a Monte Carlo calculation, making it possible to determine many properties and effects of the transport. We find that the energy scaling feature is preserved, and that the model is reasonably successful at fitting the magnitude and duration of the Fe/O ratio decrease. This along with successfully fitting the observed decrease of the O/He ratio leads us to conclude that this feature is best understood as a transport effect. Although the effects of transport, in particular adiabatic deceleration, are very significant below a few MeV nucleon –1 , the spectral break observed in these events at 1 AU is only somewhat modified by transport, and so the commonly observed spectral breaks must be present at injection. For scattering mean free paths of the order of 0.1 AU adiabatic deceleration is so large below ∼200 keV nucleon –1 that ions starting with such energies at injection are cooled sufficiently as to be

Transient magnetic fields of H-like ions in the range 10≤ZIon≤28

International Nuclear Information System (INIS)

Cub, J.

1993-07-01

Experiments with the hydrogen-like ions Ne-20, S-32, Ar-40, Fe-54 and Ni-62 were performed in order to measure the transient magnetic fields of the ions by perturbed angular correlation of the gamma radiation

Preparation and use of Cu nanoclusters as fluorescent probes to determine Au(III) ions

Energy Technology Data Exchange (ETDEWEB)

Liu, Jinshui, E-mail: jsliu@sina.com; Wang, Bin; Xu, Meijiao; Wang, Lizhen; Zhou, Zihan

2017-05-15

Polyethyleneimine-capped Cu nanoclusters (PEI-CuNCs) with a mean diameter of 2.5 nm and that emitted blue light at 485 nm were synthesized. The fluorescence of PEI-CuNCs was strongly quenched when Au(III) ions were present. Because of this specific response, a PEI-CuNC-based fluorescent turn-off sensor was developed. Under optimum conditions, a good linear relationship (R{sup 2}=0.993) was found between the relative fluorescence intensity (F{sub 0}/F) and the Au(III) ion concentration between 0.5 and 15 µM. The detection limit for Au(III) ions was 0.06 µM. The quenching mechanism was assessed by performing X-ray photoelectron spectroscopy spectra studies. The fluorescence quenching was ascribed to photo-induced electron transfer from the PEI-CuNCs to the AuCl{sub 4}{sup −} occur. Using The method described is a new way of quantifying Au(III) ions.

Immobilizing LaFeO3 nanoparticles on carbon spheres for enhanced heterogeneous photo-Fenton like performance

Science.gov (United States)

Wang, Kaixuan; Niu, Helin; Chen, Jingshuai; Song, Jiming; Mao, Changjie; Zhang, Shengyi; Gao, Yuanhao

2017-05-01

LaFeO3 nanoparticles immobilized on the surface of monodisperse carbon spheres have been obtained through a facile and environmentally friendly ultrasonic assisted surface ions adsorption method. The LaFeO3/C nanocomposite was evaluated as photo-Fenton like catalyst for the degradation of Rhodamine B (RhB) under visible light irradiation (λ > 420 nm). The LaFeO3/C nanocomposite possesses high specific surface area compared with pure LaFeO3 and significantly enhanced photo-Fenton like catalytic performance. The possible formation process of the LaFeO3/C nanocomposite and the mechanism for photo-Fenton like reaction were discussed. The superior property was attributed to the synergistic effects from the photo-Fenton like process and the presence of carbon spheres. In addition, the heterogeneous process led to better recyclability of this type of catalyst.

Recent advances in the synthesis of Fe{sub 3}O{sub 4}@AU core/shell nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Salihov, Sergei V. [National University of Science and Technology MISiS, Leninskiy, Building 9, Moscow, 119049, Russian Federation, (Russian Federation); Ivanenkov, Yan A.; Krechetov, Sergei P.; Veselov, Mark S. [Moscow Institute of Physics and Technology (State University), 9 Institutskiy lane, Dolgoprudny City, Moscow Region, 141700 (Russian Federation); Sviridenkova, Natalia V.; Savchenko, Alexander G. [National University of Science and Technology MISiS, Leninskiy, Building 9, Moscow, 119049, Russian Federation, (Russian Federation); Klyachko, Natalya L. [National University of Science and Technology MISiS, Leninskiy, Building 9, Moscow, 119049, Russian Federation, (Russian Federation); Moscow State University, Chemistry Department, Lenins kie gory, Building 1/3, GSP-1, Moscow, 119991 (Russian Federation); Golovin, Yury I. [Moscow State University, Chemistry Department, Lenins kie gory, Building 1/3, GSP-1, Moscow, 119991 (Russian Federation); Chufarova, Nina V., E-mail: chnv@pharmcluster.ru [Moscow Institute of Physics and Technology (State University), 9 Institutskiy lane, Dolgoprudny City, Moscow Region, 141700 (Russian Federation); Beloglazkina, Elena K. [National University of Science and Technology MISiS, Leninskiy, Building 9, Moscow, 119049, Russian Federation, (Russian Federation); Moscow State University, Chemistry Department, Lenins kie gory, Building 1/3, GSP-1, Moscow, 119991 (Russian Federation); Majouga, Alexander G., E-mail: majouga@org.chem.msu.ru [National University of Science and Technology MISiS, Leninskiy, Building 9, Moscow, 119049, Russian Federation, (Russian Federation); Moscow State University, Chemistry Department, Lenins kie gory, Building 1/3, GSP-1, Moscow, 119991 (Russian Federation)

2015-11-15

Fe{sub 3}O{sub 4}@Au core/shell nanoparticles have unique magnetic and optical properties. These nanoparticles are used for biomedical applications, such as magnetic resonance imaging, photothermal therapy, controlled drug delivery, protein separation, biosensors, DNA detection, and immunosensors. In this review, recent methods for the synthesis of core/shell nanoparticles are discussed. We divided all of the synthetic methods in two groups: methods of synthesis of bi-layer structures and methods of synthesis of multilayer composite structures. The latter methods have a layer of “glue” material between the core and the shell. - Highlights: • Fe{sub 3}O{sub 4} nanoparticles are promising for biomedical applications but have some disadvantages. • Covering Fe{sub 3}O{sub 4} nanoparticles with Au shell leads to better stability and biocompatibility. • Core/shell nanoparticles are widely used for biomedical applications. • There are two types of Fe{sub 3}O{sub 4}@Au core/shell nanoparticles structures: bi-layer and multilayer composite. • Different synthetic methods enable production of nanoparticles of different sizes.

Biocompatibility of Fe3O4@Au composite magnetic nanoparticles in vitro and in vivo

Directory of Open Access Journals (Sweden)

Li Y

2011-11-01

Full Text Available Yuntao Li1,2, Jing Liu1, Yuejiao Zhong3, Jia Zhang1, Ziyu Wang1, Li Wang1, Yanli An1, Mei Lin1, Zhiqiang Gao2, Dongsheng Zhang11School of Medicine, Southeast University, Nanjing, Jiangsu Province, People's Republic of China; 2Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, People's Republic of China; 3Jiangsu Cancer Hospital and Jiangsu Institute of Cancer Research, Nanjing, Jiangsu Province, People's Republic of ChinaPurpose: This research was conducted to assess the biocompatibility of the core-shell Fe3O4@Au composite magnetic nanoparticles (MNPs, which have potential application in tumor hyperthermia. Methods: Fe3O4@Au composite MNPs with core-shell structure were synthesized by reduction of Au3+ in the presence of Fe3O4-MNPs prepared by improved co-precipitation. Cytotoxicity assay, hemolysis test, micronucleus (MN assay, and detection of acute toxicity in mice and beagle dogs were then carried out.Results: The result of cytotoxicity assay showed that the toxicity grade of this material on mouse fibroblast cell line (L-929 was classified as grade 1, which belongs to no cytotoxicity. Hemolysis rates showed 0.278%, 0.232%, and 0.197%, far less than 5%, after treatment with different concentrations of Fe3O4@Au composite MNPs. In the MN assay, there was no significant difference in MN formation rates between the experimental groups and negative control (P > 0.05, but there was a significant difference between the experimental groups and the positive control (P < 0.05. The median lethal dose of the Fe3O4@Au composite MNPs after intraperitoneal administration in mice was 8.39 g/kg, and the 95% confidence interval was 6.58-10.72 g/kg, suggesting that these nanoparticles have a wide safety margin. Acute toxicity testing in beagle dogs also showed no significant difference in body weight between the treatment groups at 1, 2, 3, and 4 weeks after liver injection and no behavioral changes. Furthermore, blood

Conductivity enhancement of ion tracks in tetrahedral amorphous carbon by doping with N, B, Cu and Fe

International Nuclear Information System (INIS)

Krauser, J.; Nix, A.-K.; Gehrke, H.-G.; Hofsäss, H.; Trautmann, C.; Weidinger, A.

2012-01-01

Conducting ion tracks are formed when high-energy heavy ions (e.g. 1 GeV Au) pass through tetrahedral amorphous carbon (ta-C). These nanowires with a diameter of about 8 nm are embedded in the insulating ta-C matrix and of interest for various nanotechnological applications. Usually the overall conductivity of the tracks and the current/voltage characteristics (Ohmic or non-Ohmic) vary strongly from track to track, even when measured on the same sample, indicating that the track formation is neither complete nor homogeneous. To improve the track conductivity, doping of ta-C with N, B, Cu, or Fe is investigated. Beneficial changes in track conductivity after doping compete with a conductivity increase of the surrounding matrix material. Best results are achieved by incorporation of 1 at.% Cu, while for different reasons, the improvement of the tracks remains moderate for N, B, and Fe doping. Conductivity enhancement of the tracks is assumed to develop during the ion track formation process by an increased number of localized states which contribute to the current transport.

The Amounts of As, Au, Br, Cu, Fe, Mo, Se and Zn in Normal and Uraemic Human whole Blood. A. Comparison by Means of Neutron Activation Analysis

Energy Technology Data Exchange (ETDEWEB)

Brune, D; Samsahl, K [AB Atomenergi, Nykoeping (Sweden); Wester, P O [Dept. of Medicine, Karolinska Inst., Serafimerlasarettet, Stockholm (Sweden)

1964-01-15

Quantitative determination of the elements As, Au, Br, Cu, Fe, Mo, Se and Zn have been performed in normal and uraemic human whole blood by means of H{sub 2}SO{sub 4} - H-O- digestion, distillation and ion exchange, combined with gamma-spectrometric analysis. The uraemic blood was found to contain about 10 times as much As and twice as much Mo as did the normal blood. As regards Fe, the uraemic blood contained slightly less than the normal blood. For the other elements there were no detectable difference.

Highly Sensitive Colorimetric Assay for Determining Fe3+ Based on Gold Nanoparticles Conjugated with Glycol Chitosan

Directory of Open Access Journals (Sweden)

Kyungmin Kim

2017-01-01

Full Text Available A highly sensitive and simple colorimetric assay for the detection of Fe3+ ions was developed using gold nanoparticles (AuNPs conjugated with glycol chitosan (GC. The Fe3+ ion coordinates with the oxygen atoms of GC in a hexadentate manner (O-Fe3+-O, decreasing the interparticle distance and inducing aggregation. Time-of-flight secondary ion mass spectrometry showed that the bound Fe3+ was coordinated to the oxygen atoms of the ethylene glycol in GC, which resulted in a significant color change from light red to dark midnight blue due to aggregation. Using this GC-AuNP probe, the quantitative determination of Fe3+ in biological, environmental, and pharmaceutical samples could be achieved by the naked eye and spectrophotometric methods. Sensitive response and pronounced color change of the GC-AuNPs in the presence of Fe3+ were optimized at pH 6, 70°C, and 300 mM NaCl concentration. The absorption intensity ratio (A700/A510 linearly correlated to the Fe3+ concentration in the linear range of 0–180 μM. The limits of detection were 11.3, 29.2, and 46.0 nM for tap water, pond water, and iron supplement tablets, respectively. Owing to its facile and sensitive nature, this assay method for Fe3+ ions can be applied to the analysis of drinking water and pharmaceutical samples.

Influence of ruthenium ions on the precipitation of α-FeOOH, α-Fe2O3 and Fe3O4 in highly alkaline media

International Nuclear Information System (INIS)

Krehula, Stjepko; Music, Svetozar

2006-01-01

The influence of ruthenium ions on the precipitation of goethite (α-FeOOH), α-Fe 2 O 3 and Fe 3 O 4 in highly alkaline media was investigated by 57 Fe Moessbauer and FT-IR spectroscopies, thermal field emission scanning electron microscope (FE SEM) and EDS. The presence of Ru-dopant strongly affected the precipitation of α-FeOOH at highly alkaline pH, i.e. the formation of α-Fe 2 O 3 was also noticed. A decrease of hyperfine magnetic field (HMF) at RT from 35.1 T (undoped α-FeOOH) to 31.3 T for sample with [Ru]/([Ru] + [Fe]) = 0.0196 was assigned to the incorporation of ruthenium ions into the α-FeOOH structure. Moessbauer spectroscopy showed the formation of stoichiometric Fe 3 O 4 for [Ru]/([Ru] + [Fe]) = 0.0291-0.0909. α-Fe 2 O 3 and Fe 3 O 4 did not show a tendency to the formation of solid solutions with ruthenium ions. FE SEM observations of the samples showed that reference α-FeOOH sample contained acicular particles of good uniformity, which increased the length up to ∼5 times with increase of concentration of ruthenium ions. On the other hand, large octahedral Fe 3 O 4 crystals (particles) were associated with small particles of ruthenium (hydrous) oxide with a size in the range ∼100 nm or less. A possible catalytic action of ruthenium that created reduction conditions for Fe 3+ ions and formation of Fe 2+ ions for precipitation of Fe 3 O 4 was discussed

Preparation of Multifunctional Fe@Au Core-Shell Nanoparticles with Surface Grafting as a Potential Treatment for Magnetic Hyperthermia.

Science.gov (United States)

Chung, Ren-Jei; Shih, Hui-Ting

2014-01-24

Iron core gold shell nanoparticles grafted with Methotrexate (MTX) and indocyanine green (ICG) were synthesized for the first time in this study, and preliminarily evaluated for their potential in magnetic hyperthermia treatment. The core-shell Fe@Au nanoparticles were prepared via the microemulsion process and then grafted with MTX and ICG using hydrolyzed poly(styrene-alt-maleic acid) (PSMA) to obtain core-shell Fe@Au-PSMA-ICG/MTX nanoparticles. MTX is an anti-cancer therapeutic, and ICG is a fluorescent dye. XRD, TEM, FTIR and UV-Vis spectrometry were performed to characterize the nanoparticles. The data indicated that the average size of the nanoparticles was 6.4 ± 09 nm and that the Au coating protected the Fe core from oxidation. MTX and ICG were successfully grafted onto the surface of the nanoparticles. Under exposure to high frequency induction waves, the superparamagnetic nanoparticles elevated the temperature of a solution in a few minutes, which suggested the potential for an application in magnetic hyperthermia treatment. The in vitro studies verified that the nanoparticles were biocompatible; nonetheless, the Fe@Au-PSMA-ICG/MTX nanoparticles killed cancer cells (Hep-G2) via the magnetic hyperthermia mechanism and the release of MTX.

Sequential and double sequential fission observed in heavy ion interaction of (11.67 MeV/u)197Au projectile with 197Au target

International Nuclear Information System (INIS)

Nasir, Tabassum; Khan, Ehsan Ullah; Baluch, Javaid Jahan; Shafi-Ur-Rehman; Matiullah; Rafique, Muhammad

2009-01-01

The heavy ion interaction of 11.67 MeV/u 197 Au+ 197 Au has been investigated using mica as a passive detector. By employing Solid State Nuclear Track Detection Technique the data of elastic scattering as well as inelastic reaction channel was collected. The off-line data analysis of multi-pronged events was performed by measuring the three-dimensional geometrical coordinates of correlated tracks on event-by-event basis. Multi pronged events observed in this reaction were due to sequential and double sequential fission. Using a computer code PRONGY based on the procedure of internal calibration, it was possible to derive quantities like mass transfer, total kinetic energy loss and scattering angles. (author)

Formation of Au nanoparticles in sapphire by using Ar ion implantation and thermal annealing

International Nuclear Information System (INIS)

Zhou, L.H.; Zhang, C.H.; Yang, Y.T.; Li, B.S.; Zhang, L.Q.; Fu, Y.C.; Zhang, H.H.

2009-01-01

In this paper, we present results of the synthesis of gold nanoclusters in sapphire, using Ar ion implantation and annealing in air. Unlike the conventional method of Au implantation followed by thermal annealing, Au was deposited on the surface of m- and a- cut sapphire single crystal samples including those pre-implanted with Ar ions. Au atoms were brought into the substrate by subsequent implantation of Ar ions to form Au nanoparticles. Samples were finally annealed stepwisely in air at temperatures ranging from 400 to 800 deg. C and then studied using UV-vis absorption spectrometry, transmission electron microscopy and Rutherford backscattered spectrometry. Evidence of the formation Au nanoparticles in the sapphire can be obtained from the characteristic surface plasmon resonance (SPR) absorption band in the optical absorption spectra or directly from the transmission electron microscopy. The results of optical absorption spectra indicate that the specimen orientations and pre-implantation also influence the size and the volume fraction of Au nanoparticles formed. Theoretical calculations using Maxwell-Garnett effective medium theory supply a good interpretation of the optical absorption results.

A pulse synthesis of beta-FeSi sub 2 layers on silicon implanted with Fe sup + ions

CERN Document Server

Batalov, R I; Terukov, E I; Kudoyarova, V K; Weiser, G; Kuehne, H

2001-01-01

The synthesis of thin beta-FeSi sub 2 films was performed by means of the Fe sup + ion implantation into Si (100) and the following nanosecond pulsed ion treatment of implanted layer. Using the beta-FeSi sub 2 beta-FeSi sub 2 e X-ray diffraction it is shown that the pulsed ion treatment results in the generation of the mixture of two phases: FeSi and beta-FeSi sub 2 with stressed crystal lattices. The following short-time annealing leads to the total transformation of the FeSi phase into the beta-FeSi sub 2 one. The Raman scattering data prove the generation of the beta-FeSi sub 2 at the high degree of the silicon crystallinity. The experimental results of the optical absorption testify to the formation of beta-FeSi sub 2 layers and precipitates with the straight-band structure. The photoluminescence signal at lambda approx = 1.56 mu m observes up to 210 K

Mutagenesis in human cells with accelerated H and Fe ions

Science.gov (United States)

Kronenberg, Amy

1994-01-01

The overall goals of this research were to determine the risks of mutation induction and the spectra of mutations induced by energetic protons and iron ions at two loci in human lymphoid cells. During the three year grant period the research has focused in three major areas: (1) the acquisition of sufficient statistics for human TK6 cell mutation experiments using Fe ions (400 MeV/amu), Fe ions (600 MeV/amu) and protons (250 MeV/amu); (2) collection of thymidine kinase- deficient (tk) mutants or hypoxanthine phosphoribosyltransferase deficient (hprt) mutants induced by either Fe 400 MeV/amu, Fe 600 MeV/amu, or H 250 MeV/amu for subsequent molecular analysis; and (3) molecular characterization of mutants isolated after exposure to Fe ions (600 MeV/amu). As a result of the shutdown of the BEVALAC heavy ion accelerator in December 1992, efforts were rearranged somewhat in time to complete our dose-response studies and to complete mutant collections in particular for the Fe ion beams prior to the shutdown. These goals have been achieved. A major effort was placed on collection, re-screening, and archiving of 3 different series of mutants for the various particle beam exposures: tk-ng mutants, tk-sg mutants, and hprt-deficient mutants. Where possible, groups of mutants were isolated for several particle fluences. Comparative analysis of mutation spectra has occured with characterization of the mutation spectrum for hprt-deficient mutants obtained after exposure of TK6 cells to Fe ions (600 MeV/amu) and a series of spontaneous mutants.

Electron capture cross-section of Au-Fe complex in silicon

International Nuclear Information System (INIS)

Ali, Akbar; Shafi, M; Majid, Abdul

2006-01-01

A deep level transient spectroscopy technique is applied to study the capture cross-section of an iron-gold complex. The thermal ionization energy obtained from emission rate data is found to be E c -0.36 eV. The Au-Fe complex is a single defect having a capture cross-section of 2.48x10 -16 cm 2 for electrons which is independent of temperature

Preparation of Multifunctional Fe@Au Core-Shell Nanoparticles with Surface Grafting as a Potential Treatment for Magnetic Hyperthermia

Directory of Open Access Journals (Sweden)

Ren-Jei Chung

2014-01-01

Full Text Available Iron core gold shell nanoparticles grafted with Methotrexate (MTX and indocyanine green (ICG were synthesized for the first time in this study, and preliminarily evaluated for their potential in magnetic hyperthermia treatment. The core-shell Fe@Au nanoparticles were prepared via the microemulsion process and then grafted with MTX and ICG using hydrolyzed poly(styrene-alt-maleic acid (PSMA to obtain core-shell Fe@Au-PSMA-ICG/MTX nanoparticles. MTX is an anti-cancer therapeutic, and ICG is a fluorescent dye. XRD, TEM, FTIR and UV-Vis spectrometry were performed to characterize the nanoparticles. The data indicated that the average size of the nanoparticles was 6.4 ± 09 nm and that the Au coating protected the Fe core from oxidation. MTX and ICG were successfully grafted onto the surface of the nanoparticles. Under exposure to high frequency induction waves, the superparamagnetic nanoparticles elevated the temperature of a solution in a few minutes, which suggested the potential for an application in magnetic hyperthermia treatment. The in vitro studies verified that the nanoparticles were biocompatible; nonetheless, the Fe@Au-PSMA-ICG/MTX nanoparticles killed cancer cells (Hep-G2 via the magnetic hyperthermia mechanism and the release of MTX.

Synthesis and characterization of hollow magnetic nanospheres modified with Au nanoparticles for bio-encapsulation

Energy Technology Data Exchange (ETDEWEB)

Seisno, Satoshi, E-mail: seino@mit.eng.osaka-u.ac.jp; Suga, Kent; Nakagawa, Takashi; Yamamoto, Takao A.

2017-04-01

Hollow magnetic nanospheres modified with Au nanoparticles were successfully synthesized. Au/SiO{sub 2} nanospheres fabricated by a radiochemical process were used as templates for ferrite templating. After the ferrite plating process, Au/SiO{sub 2} templates were fully coated with magnetite nanoparticles. Dissolution of the SiO{sub 2} core lead to the formation of hollow magnetic nanospheres with Au nanoparticles inside. The hollow magnetic nanospheres consisted of Fe{sub 3}O{sub 4} grains, with an average diameter of 60 nm, connected to form the sphere wall, inside which Au grains with an average diameter of 7.2 nm were encapsulated. The Au nanoparticles immobilized on the SiO{sub 2} templates contributed to the adsorption of the Fe ion precursor and/or Fe{sub 3}O{sub 4} seeds. These hollow magnetic nanospheres are proposed as a new type of nanocarrier, as the Au grains could specifically immobilize biomolecules inside the hollow sphere. - Highlights: • A procedure to synthesize hollow magnetic nanospheres with Au inside was reported. • The Au nanoparticles inside the hollow showed high Au-S binding affinity. • The nanospheres are expected to be suitable as a new magnetic carrier for DDS.

Chiral magnetic effect search in p+Au, d+Au and Au+Au collisions at RHIC

Science.gov (United States)

Zhao, Jie

2018-01-01

Metastable domains of fluctuating topological charges can change the chirality of quarks and induce local parity violation in quantum chromodynamics. This can lead to observable charge separation along the direction of the strong magnetic field produced by spectator protons in relativistic heavy-ion collisions, a phenomenon called the chiral magnetic effect (CME). A major background source for CME measurements using the charge-dependent azimuthal correlator (Δϒ) is the intrinsic particle correlations (such as resonance decays) coupled with the azimuthal elliptical anisotropy (v2). In heavy-ion collisions, the magnetic field direction and event plane angle are correlated, thus the CME and the v2-induced background are entangled. In this report, we present two studies from STAR to shed further lights on the background issue. (1) The Δϒ should be all background in small system p+Au and d+Au collisions, because the event plane angles are dominated by geometry fluctuations uncorrelated to the magnetic field direction. However, significant Δϒ is observed, comparable to the peripheral Au+Au data, suggesting a background dominance in the latter, and likely also in the mid-central Au+Au collisions where the multiplicity and v2 scaled correlator is similar. (2) A new approach is devised to study Δϒ as a function of the particle pair invariant mass (minv) to identify the resonance backgrounds and hence to extract the possible CME signal. Signal is consistent with zero within uncertainties at high minv. Signal at low minv, extracted from a two-component model assuming smooth mass dependence, is consistent with zero within uncertainties.

Excited-State N2 Dissociation Pathway on Fe-Functionalized Au.

Science.gov (United States)

Martirez, John Mark P; Carter, Emily A

2017-03-29

Localized surface plasmon resonances (LSPRs) offer the possibility of light-activated chemical catalysis on surfaces of strongly plasmonic metal nanoparticles. This technology relies on lower-barrier bond formation and/or dissociation routes made available through energy transfer following the eventual decay of LSPRs. The coupling between these decay processes and a chemical trajectory (nuclear motion, charge-transfer, intersystem crossing, etc.) dictates the availability of these alternative (possibly lower barrier) excited-state channels. The Haber-Bosch method of NH 3 synthesis from N 2 and H 2 is notoriously energy intensive. This is due to the difficulty of N 2 dissociation despite the overall reaction being thermodynamically favorable at ambient temperatures and pressures. LSPRs may provide means to improve the kinetics of N 2 dissociation via induced resonance electronic excitation. In this work, we calculate, via embedded n-electron valence second-order perturbation theory within the density functional embedding theory, the excited-state potential energy surfaces for dissociation of N 2 on an Fe-doped Au(111) surface. This metal alloy may take advantage simultaneously of the strong LSPR of Au and the catalytic activity of Fe toward N 2 dissociation. We find the ground-state dissociation activation energy to be 4.74 eV/N 2 , with Fe as the active site on the surface. Consecutive resonance energy transfers (RETs) may be accessed due to the availability of many electronically excited states with intermediate energies arising from the metal surface that may couple to states induced by the Fe-dopant and the adsorbate molecule, and crossing between excited states may effectively lower the dissociation barrier to 1.33 eV. Our work illustrates that large energetic barriers, prohibitive toward chemical reaction, may be overcome through multiple RETs facilitating an otherwise difficult chemical process.

Schiff Base Ligand Coated Gold Nanoparticles for the Chemical Sensing of Fe(III Ions

Directory of Open Access Journals (Sweden)

Abiola Azeez Jimoh

2015-01-01

Full Text Available New Schiff base-coated gold nanoparticles (AuNPs of type AuNP@L (where L: thiolated Schiff base ligand have been synthesized and characterized using various spectroscopic techniques. The AuNPs and AuNP@L were imaged by transmission electron microscopy (TEM and were confirmed to be well-dispersed, uniformly distributed, spherical nanoparticles with an average diameter of 8–10 nm. Their potential applications for chemosensing were investigated in UV-Vis and fluorescence spectroscopic studies. The AuNP@L exhibited selectivity for Fe3+ in an ethanol/water mixture (ratio 9 : 1 v/v. The absorption and emission spectral studies revealed a 1 : 1 binding mode for Fe3+, with binding constants of 8.5×105 and 2.9×105 M−1, respectively.

Shaping of Au nanoparticles embedded in various layered structures by swift heavy ion beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Dawi, E.A., E-mail: elmuez.dawi@gmail.com [Ajman University of Science and Technology, Basic Science and Education, Physics Department, P.O. Box 346 (United Arab Emirates); Debye Institute for Nanomaterials, Nanophotonics Section, Utrecht University, P.O. Box 80000, 3508 TA Utrecht (Netherlands); ArnoldBik, W.M. [Eindhoven University of Technology, Irradiation Technology, 5600 GM Eindhoven (Netherlands); Ackermann, R.; Habraken, F.H.P.M. [Debye Institute for Nanomaterials, Nanophotonics Section, Utrecht University, P.O. Box 80000, 3508 TA Utrecht (Netherlands)

2016-10-01

We present a novel method to extend the ion-beam induced shaping of metallic nanoparticles in various layered structures. Monodisperse Au nanoparticles having mean diameter of 30 nm and their ion-shaping process is investigated for a limited number of experimental conditions. Au nanoparticles were embedded within a single plane in various layered structures of silicon nitride films (Si{sub 3}N{sub 4}), combinations of oxide-nitride films (SiO{sub 2}-Si{sub 3}N{sub 4}) and amorphous silicon films (a-Si) and have been sequentially irradiated at 300 K at normal incidence with 50 and 25 MeV Ag ions, respectively. Under irradiation with heavy Ag ions and with sequential increase of the irradiation fluence, the evolution of the Au peak derived from the Rutherford Backscattering Spectrometry show broadening in Au peak, which indicates that the Au becomes distributed over a larger depth region, indicative of the elongation of the nanoparticles. The latter is observed almost for every layer structure investigated except for Au nanoparticles embedded in pure a-Si matrix. The largest elongation rate at all fluences is found for the Au nanoparticles encapsulated in pure Si{sub 3}N{sub 4} films. For all irradiation energy applied, we again demonstrate the existence of both threshold and saturation fluences for the elongation effects mentioned.

A Novel 2D Porous Print Fabric-like α-Fe_2O_3 Sheet with High Performance as the Anode Material for Lithium-ion Battery

International Nuclear Information System (INIS)

Zhang, Suyue; Zhang, Peigen; Xie, Anjian; Li, Shikuo; Huang, Fangzhi; Shen, Yuhua

2016-01-01

Anode materials are very crucial in lithium ion batteries. Exploring the simple and low cost production of anodes with excellent electrochemical performance remains a great challenge. Here, we used natural flower spikes of Typha orientalis as the bio-templates and organizers to prepare a novel two-dimensional (2D) porous print fabric-like α-Fe_2O_3 sheet with thickness of about 30 nm. The prepared large-area sheets were orderly assembled by many nanosheets or nanoparticles, and two kinds of pore structures, such as pores with average diameter of about 50 nm or pore channels with aspect ratio of ca. 4, presented between adjacent nanosheets. The pre-treatment by ammonium for flower spikes has a great effect on the microstructure and electrochemical performance of the products. As the anode material for lithium ion battery (LIB), the as-obtained porous print fabric-like α-Fe_2O_3 sheets show an initial discharge capacity of 2264 mA h g"−"1 and the specific capacity of 1028 mA h g"−"1 after 100 cycles at a current density of 500 mA g"−"1, which is higher than the theoretical capacity of α-Fe_2O_3 (1007 mA h g"−"1). This highly reversible capacity is attributed to the very thin large-area sheet structure, and many pores or pore channels among the interconnected nanosheets, which could increase lithium-ion mobility, facilitate the transport of electrons and shorten the distance for Li"+ diffusion, and also buffer large volume changes of the anodes during lithium insertion and extraction at the same time. The synthesis process is very simple, providing a low-cost production approach toward high-performance energy storage materials.

Source Population and Acceleration Location of Suprathermal Heavy Ions in Corotating Interaction Regions

Energy Technology Data Exchange (ETDEWEB)

Filwett, R. J.; Desai, M. I. [University of Texas at San Antonio, San Antonio, TX (United States); Dayeh, M. A.; Broiles, T. W. [Southwest Research Institute, San Antonio, TX (United States)

2017-03-20

We have analyzed the ∼20–320 keV nucleon{sup −1} suprathermal (ST) heavy ion abundances in 41 corotating interaction regions (CIRs) observed by the Wind spacecraft from 1995 January to 2008 December. Our results are: (1) the CIR Fe/CNO and NeS/CNO ratios vary with the sunspot number, with values being closer to average solar energetic particle event values during solar maxima and lower than nominal solar wind values during solar minima. The physical mechanism responsible for the depleted abundances during solar minimum remains an open question. (2) The Fe/CNO increases with energy in the 6 events that occurred during solar maximum, while no such trends are observed for the 35 events during solar minimum. (3) The Fe/CNO shows no correlation with the average solar wind speed. (4) The Fe/CNO is well correlated with the corresponding upstream ∼20–320 keV nucleon{sup −1} Fe/CNO and not with the solar wind Fe/O measured by ACE in 31 events. Using the correlations between the upstream ∼20–40 keV nucleon{sup −1} Fe/CNO and the ∼20–320 keV nucleon{sup −1} Fe/CNO in CIRs, we estimate that, on average, the ST particles traveled ∼2 au along the nominal Parker spiral field line, which corresponds to upper limits for the radial distance of the source or acceleration location of ∼1 au beyond Earth orbit. Our results are consistent with those obtained from recent surveys, and confirm that CIR ST heavy ions are accelerated more locally, and are at odds with the traditional viewpoint that CIR ions seen at 1 au are bulk solar wind ions accelerated between 3 and 5 au.

NaAuS chicken-wire-like semiconductor: Electronic structure and optical properties

International Nuclear Information System (INIS)

Reshak, A.H.; Khan, Saleem Ayaz; Kamarudin, H.; Bila, Jiri

2014-01-01

Highlights: • Chicken wire like semiconductor NaAuS was investigated. • Good agreement with experimental data was found. • Electronic charge density of chicken wire like semiconductor NaAuS was obtained. • The calculated uniaxial anisotropy is −0.0005, indicating the strong anisotropy. -- Abstract: The electronic structure, charge density and optical properties of NaAuS a chicken-wire-like semiconductor was calculated using full potential linear augmented plane wave based on density functional theory. The Ceperley-Alder local density approximation, Perdew Becke Ernzerhof Generalized gradient approximation and Engel Voskov Generalized Gradient Approximation were applied to solve the exchange correlation potential. The investigation of band structures and density of states elucidates that Engle Vasko Generalized Gradient Approximation shows close agreement to the experimental data. The calculated valence charge density shows pure ionic nature of Au–Au bond. It becomes partially covalent when Au is connected with two Na atoms. The linear optical susceptibilities of chicken-wire-like NaAuS semiconductor are calculated so as to obtain further insight into the electronic properties. The uniaxial anisotropy is −0.0005, indicating the strong anisotropy of the dielectric function in the NaAuS a chicken-wire-like semiconductor

NaAuS chicken-wire-like semiconductor: Electronic structure and optical properties

Energy Technology Data Exchange (ETDEWEB)

Reshak, A.H. [Institute of Complex Systems, FFPW, CENAKVA, University of South Bohemia in CB, Nove Hrady 37333 (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Khan, Saleem Ayaz, E-mail: sayaz_usb@yahoo.com [Institute of Complex Systems, FFPW, CENAKVA, University of South Bohemia in CB, Nove Hrady 37333 (Czech Republic); Kamarudin, H. [Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Bila, Jiri [Department of Instrumentation and Control Engineering, Faculty of Mechanical Engineering, CTU in Prague, Technicka 4, 166 07 Prague 6 (Czech Republic)

2014-01-05

Highlights: • Chicken wire like semiconductor NaAuS was investigated. • Good agreement with experimental data was found. • Electronic charge density of chicken wire like semiconductor NaAuS was obtained. • The calculated uniaxial anisotropy is −0.0005, indicating the strong anisotropy. -- Abstract: The electronic structure, charge density and optical properties of NaAuS a chicken-wire-like semiconductor was calculated using full potential linear augmented plane wave based on density functional theory. The Ceperley-Alder local density approximation, Perdew Becke Ernzerhof Generalized gradient approximation and Engel Voskov Generalized Gradient Approximation were applied to solve the exchange correlation potential. The investigation of band structures and density of states elucidates that Engle Vasko Generalized Gradient Approximation shows close agreement to the experimental data. The calculated valence charge density shows pure ionic nature of Au–Au bond. It becomes partially covalent when Au is connected with two Na atoms. The linear optical susceptibilities of chicken-wire-like NaAuS semiconductor are calculated so as to obtain further insight into the electronic properties. The uniaxial anisotropy is −0.0005, indicating the strong anisotropy of the dielectric function in the NaAuS a chicken-wire-like semiconductor.

Synthesis of Core/Shell MnFe2O4/Au Nanoparticles for Advanced Proton Treatment

International Nuclear Information System (INIS)

Park, Jeong Chan

2014-01-01

Among many approaches for the surface modification with materials, such as polymers, organic ligands and metals, one of the most attractive ways is using metals. The fabrication of metal-based, monolayer-coated magnetic nanoparticles has been intensively studied. However, the synthesis of metal-capped magnetic nanoparticles with monodIspersities and controllable sizes is still challenged. Recently, gold-capped magnetic nanoparticles have been reported to increase stability and to provide biocompatibility. Magnetic nanoparticle with gold coating is an attractive system, which can be stabilized in biological conditions and readily functionalized through well-established surface modification (Au-S) chemistry. The Au coating offers plasmonic properties to magnetic nanoparticles. The core/shell nanoparticles were transferred from organic to aqueous solutions for biomedical applications. The core/shell structured MnFe 2 O 4 /Au nanoparticles have been prepared and transferred from organic phase to aqueous solutions. The resulting Au-coated nanocrystals may be an attractive system for biomedical applications, which are needed both magnetic resonance imaging and optical imaging. The phase transferred core/shell nanoparticles can be decorated with targeting moiety, such as antibodies, peptides, aptamers, small molecules and ligands for biological applications. The proton treatment with the resulting Au-MnFe 2 O 4 nanoparticles is undergoing.

A thermodynamic evaluation of the potential for cryptic formation of incidental Au-Fe alloy catalysts during flexible cell experimental studies of abiotic alkanogenesis during serpentinization

Science.gov (United States)

Lazar, C.

2017-12-01

The formation of abiotic alkanes via CO2 reduction during serpentinization is an important process in astrobiology and geochemistry. Aqueous alkane concentrations in natural settings are often non-equilibrated, thus motivating many experimental studies of CO2 reduction kinetics. A well-established result of such studies is the strong catalytic effect of metallic Feo on the conversion rate of CO2 to alkanes. Because alkanogenetic serpentinization experiments often feature Fe-bearing minerals contained in gold vessels, incidental metallic Feo may precipitate during an experiment as Au-Fe alloy. Such alloy may be catalytic, potentially leading to artificially rapid alkanogenesis and an overestimation of the catalytic strength of nominally nonmetallic Fe-bearing minerals, even if isotopically labeled 13C is used. To evaluate this potential for Au-Fe alloying, a thermodynamic analysis of the effect of oxygen fugacity on Au-Fe mixing has been performed at metamorphic grades relevant to experimental alkanogenesis. The results show that even relatively oxidized metal-free mineral assemblages such as the quartz-fayalite-magnetite buffer (QFM) can stably coexist with an Au-Fe alloy containing a few hundred ppm Fe. Given the strong catalytic effect of metallic Fe, any hydrocarbons generated during a hypothetical experiment containing, for example, the QFM assemblage might be catalyzed by trace Fe in an Au-Fe alloy, not by a QFM mineral. The effect is stronger for assemblages more reducing than QFM, which are notably common in serpentinites. This is a source of experimental uncertainty in reusable flexible gold cell apparatus that cannot be assessed by traditional blank experiments, which only demonstrate the effectiveness of post-run acid-cleaning procedures. A more effective approach would be the chemical analysis of a small, recoverable gold chip embedded into the experimental materials. By assuming that the experimental materials interact identically with the Au chip and

Optimization of the composition of bimetallic core/shell Fe2O3/Au nanoparticles for MRI/CT dual-mode imaging

International Nuclear Information System (INIS)

Zhang, Song; Qi, Yueyong; Yang, Hua; Gong, Mingfu; Zhang, Dong; Zou, Liguang

2013-01-01

Bimetallic core/shell Fe 2 O 3 /Au nanoparticles are promising candidate dual-mode contrast agents for magnetic resonance imaging (MRI) and computed tomography (CT) imaging. However, the gold coating on the hybrid nanoparticles (hybrids) affects the MRI and CT imaging quality. A thick gold nanoshell increases the X-ray attenuation effect but decreases the magnetic saturation of the hybrids. Therefore, we studied the effect of the Fe 2 O 3 and Au composition on these properties to find a suitable hybrid for MRI and CT imaging. Water-soluble, Au-coated magnetic nanoparticles were synthesized by iteratively reducing Au 3+ onto the Fe 2 O 3 surface via hydroxylamine seeding. The properties of the hybrids obtained after different numbers of Au seeding cycles were studied using transmission electron microscopy, UV–Vis spectrophotometry, a vibrating swatch gaussmeter, MRI, CT, and an MTT assay. The hybrids obtained after three Au seeding cycles had an Fe 2 O 3 :Au molar ratio of 7.2:26.8, a mean diameter of 48.3 nm, a UV–Vis absorbance peak of 550 nm, a saturation magnetization of 49.0 emu/g, and no cytotoxicity at a concentration of 500 μg/mL after incubation with RAW 264.7 cells for up to 72 h. The hybrids obtained after three Au seeding cycles are the preferred candidates for MRI and CT applications because of their relatively high R2 relaxivity (95 mM −1  s −1 ) and X-ray attenuation (1.87 times that of iodine) compared to those of the other hybrids investigated in this study

Electron capture cross-section of Au-Fe complex in silicon

Energy Technology Data Exchange (ETDEWEB)

Ali, Akbar; Shafi, M; Majid, Abdul [Advance Materials Physics Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad (Pakistan)

2006-10-15

A deep level transient spectroscopy technique is applied to study the capture cross-section of an iron-gold complex. The thermal ionization energy obtained from emission rate data is found to be E{sub c} -0.36 eV. The Au-Fe complex is a single defect having a capture cross-section of 2.48x10{sup -16} cm{sup 2} for electrons which is independent of temperature.

On the electronic, structural, and thermodynamic properties of Au supported on α-Fe{sub 2}O{sub 3} surfaces and their interaction with CO

Energy Technology Data Exchange (ETDEWEB)

Nguyen, Manh-Thuong, E-mail: manhth.nguyen@gmail.com; Gebauer, Ralph [The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste (Italy); Farnesi Camellone, Matteo, E-mail: mfarnesi@sissa.it [CNR-IOM DEMOCRITOS, Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche and SISSA Scuola Internazionale di Studi Superiori Avanzati, Via Bonomea 265, I-34136 Trieste (Italy)

2015-07-21

Extensive first principles calculations are carried out to investigate Au monomers and dimers supported on α-Fe{sub 2}O{sub 3}(0001) surfaces in terms of structure optimizations, electronic structure analyses, and ab initio thermodynamics calculations of surface phase diagrams. All computations rely on density functional theory in the generalized gradient approximation (Perdew-Burke-Ernzerhof (PBE)) and account for on-site Coulomb interactions via inclusion of a Hubbard correction (PBE+U). The relative stability of Au monomers/dimers on the stoichiometric termination of α-Fe{sub 2}O{sub 3}(0001) decorated with various vacancies (multiple oxygen vacancies, iron vacancy, and mixed iron-oxygen vacancies) has been computed as a function of the oxygen chemical potential. The charge rearrangement induced by Au at the oxide contact is analyzed in detail and discussed. On one hand, ab initio thermodynamics predicts that under O-rich conditions, structures obtained by replacing a surface Fe atom with a Au atom are thermodynamically stable over a wide range of temperatures. On the other hand, the complex of a CO molecule on a Au atom substituting surface Fe atoms is thermodynamically stable only in a much more narrow range of values of the O chemical potential under O-rich conditions. In the case of a Au dimer, under O-rich conditions, supported Au atoms at an O-Fe di-vacancy are more stable. However, upon CO adsorption, the complex of a CO molecule and 2 Au atoms located at a single Fe vacancy is more favorable.

Functionalization of Fe3O4/SiO2 with N-(2-Aminoethyl-3-aminopropyl for Sorption of [AuCl4]-

Directory of Open Access Journals (Sweden)

Nuryono Nuryono

2016-08-01

Full Text Available Synthesis of Fe3O4/SiO2 modified with N-(2-aminoethyl-3-aminopropyl group (Fe3O4/SiO2/ED via coating method and its application for adsorption-desorption of anionic gold in aqueous solution have been conducted. The synthesized product was characterized with an X-ray diffractometer (XRD, a Fourier transform infrared (FT-IR spectrophotometer and a transmission electron microscopy (TEM. Adsorption of Au(III was conducted in a batch system and the variables included pH, contact time, and initial concentration were investigated. Results showed that magnetite/silica has been successfully functionalized with N-(2-aminoethyl-3-aminopropyl in a homogeneous system. Kinetics study showed that adsorption of Au(III followed the pseudo-second order model with rate constant of 0.710 g mmol L-1min-1. Furthermore, the experimental data fitted well with the Langmuir isotherm model with the maximum adsorption capacity for Au(III of 142.9 mg g-1 and the energy of 25.0 kJ mol-1. Gold loaded on the Fe3O4/SiO2/ED could be easily desorbed with 0.2 mol L-1 HCl containing 2 wt.% of thiourea with recovery of 99.8%. Fe3O4/SiO2/ED was reusable and stable in 5 cycles of adsorption-desorption with recovery more than 90%. Fe3O4/SiO2/ED showed high selectivity towards Au(III in the multimetal system Au(III/Cu(II/Cr(VI with the coefficient selectivity for αAu-Cu of 227.5and for αAu-Cr of 12.3.

The sandwich-type electrochemiluminescence immunosensor for α-fetoprotein based on enrichment by Fe3O4-Au magnetic nano probes and signal amplification by CdS-Au composite nanoparticles labeled anti-AFP.

Science.gov (United States)

Zhou, Hankun; Gan, Ning; Li, Tianhua; Cao, Yuting; Zeng, Saolin; Zheng, Lei; Guo, Zhiyong

2012-10-09

A novel and sensitive sandwich-type electrochemiluminescence (ECL) immunosensor was fabricated on a glassy carbon electrode (GCE) for ultra trace levels of α-fetoprotein (AFP) based on sandwich immunoreaction strategy by enrichment using magnetic capture probes and quantum dots coated with Au shell (CdS-Au) as the signal tag. The capture probe was prepared by immobilizing the primary antibody of AFP (Ab1) on the core/shell Fe(3)O(4)-Au nanoparticles, which was first employed to capture AFP antigens to form Fe(3)O(4)-Au/Ab1/AFP complex from the serum after incubation. The product can be separated from the background solution through the magnetic separation. Then the CdS-Au labeled secondary antibody (Ab2) as signal tag (CdS-Au/Ab2) was conjugated successfully with Fe(3)O(4)-Au/Ab1/AFP complex to form a sandwich-type immunocomplex (Fe(3)O(4)-Au/Ab1/AFP/Ab2/CdS-Au), which can be further separated by an external magnetic field and produce ECL signals at a fixed voltage. The signal was proportional to a certain concentration range of AFP for quantification. Thus, an easy-to-use immunosensor with magnetic probes and a quantum dots signal tag was obtained. The immunosensor performed at a level of high sensitivity and a broad concentration range for AFP between 0.0005 and 5.0 ng mL(-1) with a detection limit of 0.2 pg mL(-1). The use of magnetic probes was combined with pre-concentration and separation for trace levels of tumor markers in the serum. Due to the amplification of the signal tag, the immunosensor is highly sensitive, which can offer great promise for rapid, simple, selective and cost-effective detection of effective biomonitoring for clinical application. Copyright © 2012 Elsevier B.V. All rights reserved.

Highly efficient and porous TiO{sub 2}-coated Ag@Fe{sub 3}O{sub 4}@C-Au microspheres for degradation of organic pollutants

Energy Technology Data Exchange (ETDEWEB)

Shen, Mao, E-mail: shenmao19820808@163.com; Chen, Suqing, E-mail: 465060605@qq.com; Jia, Wenping, E-mail: tzcjwp@tzc.edu.cn [Taizhou University, College of Pharmaceutical and Chemical Engineering (China); Fan, Guodong, E-mail: fangd@sust.edu.cn [Shan xi University of Science and Technology, Key Laboratory of Auxiliary Chemistry and Technology for Chemical Industry, Ministry of Education (China); Jin, Yanxian, E-mail: shirleyj@tzc.edu.cn; Liang, Huading, E-mail: shanjian8208@163.com [Taizhou University, College of Pharmaceutical and Chemical Engineering (China)

2016-12-15

In this paper, we reported a novel hierarchical porous Ag@Fe{sub 3}O{sub 4}@C-Au@TiO{sub 2} core@shell microspheres with a highly photocatalytic activity and magnetically separable properties. The synthesis method is included of a Fe{sub 3}O{sub 4} magnetic embedded Ag core (Ag@Fe{sub 3}O{sub 4}), an interlayer of carbon modified by PEI to form sufficient amounts of amine functional groups (Ag@Fe{sub 3}O{sub 4}@C-PEI), the grafting of Au nanoparticles on the surface of Ag@Fe{sub 3}O{sub 4}@C-PEI (Ag@Fe{sub 3}O{sub 4}@C-Au), and an ordered porous TiO{sub 2} structured shell. As an example of the applications, the photocatalytic activities of the samples were investigated by the reduction of Rhodamine B (RhB) under visible-light irradiation. The results show that the porous Ag@Fe{sub 3}O{sub 4}@C-Au@TiO{sub 2} core@shell microspheres display higher adsorption and photocatalytic activities compared to the pure porous TiO{sub 2} and Ag@Fe{sub 3}O{sub 4}@C@TiO{sub 2} microspheres, which are attributed to the local surface plasmon resonance (LSPR) by the Ag and Au nanoparticles and the high specific surface area.

Above-surface neutralization of multicharged ions incident on a cesiated Au target

International Nuclear Information System (INIS)

Meyer, F.W.; Hughes, I.G.; Overbury, S.H.

1992-01-01

The critical distance above the surface at which conduction band electrons can start to neutralize incident multicharged projectiles by classical overbarrier transitions is inversely proportional to the metal work function. By varying the amount of Cs coverage on a Au single crystal target between O and 1 monolayers, the authors have been able to verify an up to 3.3 eV decrease of the surface work function, corresponding to more than a factor of two decrease relative to that tabulated for clean Au. This change should result in more than doubling the above-surface interaction time. At larger above-surface distances, however, the electron capture most likely occurs into higher principal quantum numbers of the projectile. The subsequent de-excitation cascade by which inner shells of the projectiles are populated may thus require more time. The authors have investigated the overall effect that lowering the work function has on the above-surface component of projectile K-Auger electron emission for grazing incidence N 6+ ions interacting with cesiated Au single crystals. They will present results showing that an enhancement of this component is indeed observed, and that it is strongly dependent on incidence angle

Sequential and double sequential fission observed in heavy ion interaction of (11.67 MeV/u){sup 197}Au projectile with {sup 197}Au target

Energy Technology Data Exchange (ETDEWEB)

Nasir, Tabassum [Gomal University, Dera Ismail Khan (Pakistan). Dept. of Physics; Khan, Ehsan Ullah [COMSATS Institute of Information Technology (CIIT), Islamabad (Pakistan). Dept. of Physics; Baluch, Javaid Jahan [COMSATS Institute of Information Technology (CIIT), Abbottabad, (Pakistan). Dept. of Environmental Sciences; Shafi-Ur-Rehman, [PAEC, Dera Ghazi Khan (Pakistan). ISL Project; Matiullah, [PINSTECH, Nilore, Islamabad (Pakistan). Physics Div.; Rafique, Muhammad [University of Azad Jammu and Kashmir, Muzaffarabad (Pakistan). Dept. of Physics

2009-09-15

The heavy ion interaction of 11.67 MeV/u {sup 197}Au+ {sup 197}Au has been investigated using mica as a passive detector. By employing Solid State Nuclear Track Detection Technique the data of elastic scattering as well as inelastic reaction channel was collected. The off-line data analysis of multi-pronged events was performed by measuring the three-dimensional geometrical coordinates of correlated tracks on event-by-event basis. Multi pronged events observed in this reaction were due to sequential and double sequential fission. Using a computer code PRONGY based on the procedure of internal calibration, it was possible to derive quantities like mass transfer, total kinetic energy loss and scattering angles. (author)

Transient field measurements on 56Fe- and 80Se-ions using segmented Fe-layers

International Nuclear Information System (INIS)

Busch, H.; Kremeyer, S.; Meens, A.; Maier-Komor, P.

1996-01-01

Measurements of transient magnetic fields (TF) were performed on swift heavy ions of 56 Fe and 80 Se, with Coulomb excitation of their first 2 + state as probe, traversing thin Fe layers with segmented and unsegmented structures. The 50 μm x 50 μm squares of the segments were accomplished applying the techniques of photolithography and ion etching. The magnitude of the TF deduced clearly shows that by segmentation of the targets the ion beam induced attenuations can be eliminated. This finding has direct applications to g-factor measurements. (orig.)

One-dimensional fossil-like γ-Fe2O3@carbon nanostructure: preparation, structural characterization and application as adsorbent for fast and selective recovery of gold ions from aqueous solution

Science.gov (United States)

Gunawan, Poernomo; Xiao, Wen; Hao Chua, Marcus Wen; Poh-Choo Tan, Cheryl; Ding, Jun; Zhong, Ziyi

2016-10-01

One-dimensional (1D) magnetic nanostructures with high thermal stability have important industrial applications, but their fabrication remains a big challenge. Herein we demonstrate a scalable approach for the preparation of stable 1D γ-Fe2O3@carbon, which is also applicable for other metal oxide-core and carbon-shell nanostructures, such as 1D TiO2@carbon. One-dimensional ferric oxyhydroxide (α-FeO(OH)) was initially prepared by a hydrothermal method, followed by carbon coating through hydrothermal treatment of the resulting metal oxide in glucose solution. After calcination in N2 gas at 500 °C and subsequent exposure to air, the initial carbon-coated 1D α-Fe2O3 was converted to 1D γ-Fe2O3@carbon, which was very stable without any observed changes even after 1.5 years of storage under ambient conditions. The materials were then used as adsorbents and found to be highly selective towards Au (III) adsorption, of which the maximum adsorption capacity is about 600 mg Au/g sorbent (1132 mg Au/g carbon). The spent sorbent containing Au after adsorption can be readily collected by applying a magnetic field due to the presence of the magnetic core, and the adsorbed Au particles are subsequently recovered after the combustion and dissolution of the sorbent. This work demonstrates not only a facile approach to the fabrication of robust 1D magnetic materials with a stable carbon shell, but also a possible cyanide-free process for the fast and selective recovery of gold from electronic waste and industrial water.

Interdiffusion and grain-boundary migration in Au-Cu bilayers during ion-irradiation

International Nuclear Information System (INIS)

Alexander, D.E.; Rehn, L.E.; Baldo, P.M.

1991-11-01

Ion irradiation and annealing experiments have been conducted on Au/Cu bilayer films to evaluate the effect of irradiation on diffusion-induced grain boundary migration (DIGM). The Au films were prepared with a large-grained microstructure with grain boundaries perpendicular to the film surface and extending through the film thickness. Irradiations were conducted with 1.5 MeV Kr at 228 degree C. Rutherford backscattering spectrometry of the samples revealed that interdiffusion was substantially enhanced in the irradiated area relative to the unirradiated area. Both irradiated and annealed-only areas were characterized by a nearly uniform composition of 14 at.% and 7 at.% Cu respectively through the entire thickness of the underlying Au film. Small probe X-ray energy dispersive spectroscopy showed significant lateral compositional homogeneities in both irradiated and annealed areas. These two results are consistent with previous observations of DIGM in the Au/Cu system, suggesting that this previously unexamined mechanism contributes to ion beam mixing

Fe(III) and Fe(II) ions different effects on Enterococcus hirae cell growth and membrane-associated ATPase activity

Energy Technology Data Exchange (ETDEWEB)

Vardanyan, Zaruhi [Department of Biophysics of the Biology Faculty, Yerevan State University, 1 A. Manoukian Str., 0025 Yerevan (Armenia); Trchounian, Armen, E-mail: trchounian@ysu.am [Department of Biophysics of the Biology Faculty, Yerevan State University, 1 A. Manoukian Str., 0025 Yerevan (Armenia)

2012-01-06

Highlights: Black-Right-Pointing-Pointer Fe{sup 3+} stimulates but Fe{sup 2+} suppresses Enterococcus hirae wild-type and atpD mutant growth. Black-Right-Pointing-Pointer Fe ions change oxidation-reduction potential drop during cell growth. Black-Right-Pointing-Pointer Fe{sup 3+} and Fe{sup 2+} have opposite effects on a membrane-associated ATPase activity. Black-Right-Pointing-Pointer These effects are either in the presence of F{sub 0}F{sub 1} inhibitor or non-functional F{sub 0}F{sub 1}. Black-Right-Pointing-Pointer Fe ions decrease protons and coupled potassium ions fluxes across the membrane. -- Abstract: Enterococcus hirae is able to grow under anaerobic conditions during glucose fermentation (pH 8.0) which is accompanied by acidification of the medium and drop in its oxidation-reduction potential (E{sub h}) from positive values to negative ones (down to {approx}-200 mV). In this study, iron (III) ions (Fe{sup 3+}) have been shown to affect bacterial growth in a concentration-dependent manner (within the range of 0.05-2 mM) by decreasing lag phase duration and increasing specific growth rate. While iron(II) ions (Fe{sup 2+}) had opposite effects which were reflected by suppressing bacterial growth. These ions also affected the changes in E{sub h} values during bacterial growth. It was revealed that ATPase activity with and without N,N Prime -dicyclohexylcarbodiimide (DCCD), an inhibitor of the F{sub 0}F{sub 1}-ATPase, increased in the presence of even low Fe{sup 3+} concentration (0.05 mM) but decreased in the presence of Fe{sup 2+}. It was established that Fe{sup 3+} and Fe{sup 2+} both significantly inhibited the proton-potassium exchange of bacteria, but stronger effects were in the case of Fe{sup 2+} with DCCD. Such results were observed with both wild-type ATCC9790 and atpD mutant (with defective F{sub 0}F{sub 1}) MS116 strains but they were different with Fe{sup 3+} and Fe{sup 2+}. It is suggested that the effects of Fe{sup 3+} might be due to

High rectification ratios of Fe-porphyrin molecules on Au facets

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiaoyu; Wang, Gwo-Ching [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, 110, 8th Street, Troy, NY 12180 (United States); Lewis, Kim M., E-mail: lewisk2@rpi.edu [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, 110, 8th Street, Troy, NY 12180 (United States)

2012-09-14

We report room temperature measurements of current vs. voltage (I-V) from self-assembled Fe porphyrin [Fe(III) 5,15-di[4-(s-acetylthio)phenyl]-10,20-diphenyl porphine] molecular layers formed on annealed gold crystal facets on glass substrates. I-V curves were measured using an atomic force microscope with a conductive platinum tip. We observed a rectifier effect that shows asymmetric I-V curves from a monolayer of molecules. The majority rectification ratios at {+-}1 V obtained from hundreds of I-V lie in between 20 and 200, with the highest up to 9000. This is in contrast to the symmetric I-V curves measured from a few nm thick multilayer molecular islands. We contribute the observed rectification in ultrathin FeP molecular layers from asymmetric Schottky barriers that result from molecules in different bonding strengths to electrodes of gold and platinum. -- Highlights: Black-Right-Pointing-Pointer FeP molecular layers or islands of different thickness were self-assembled on Au. Black-Right-Pointing-Pointer High rectification ratios up to 9000 observed in sub-nm thick FeP molecular layers. Black-Right-Pointing-Pointer Measured current vs. voltage using a conductive AFM tip as one electrode. Black-Right-Pointing-Pointer Observed rectification of symmetric molecules using two different electrodes.

Bound states of hydrogen-like ions in Debye plasma

International Nuclear Information System (INIS)

Li Bowen; Jiang Jun; Kang Weimin; Yang Ningxuan; Dong Chenzhong

2009-01-01

The plasma screening effects on the energy levels and wave functions of hydrogen-like ions were estimated by using Debye model. The effects on n l(n=1-4, l=0-3) energy levels and wave functions of hydrogen and Fe 25+ ion versus screening lengths λ have been analyzed. Furthermore, the screening effects versus quantum number n and l has been analyzed. The results show that the screening effects increasing as n increasing and decreasing as l increasing. Last, the Eigenergies of isoelectronic series change against screening parameter λ has been discussed, it's shown that the plasma screening effects are decreasing as nuclear charge increasing. (authors)

Damage induced by helium ion irradiation in Fe-based metallic glass

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiaonan; Mei, Xianxiu, E-mail: xxmei@dlut.edu.cn; Zhang, Qi; Li, Xiaona; Qiang, Jianbing; Wang, Younian

2017-07-15

The changes in structure and surface morphology of metallic glasses Fe{sub 80}Si{sub 7.43}B{sub 12.57} and Fe{sub 68}Zr{sub 7}B{sub 25} before and after the irradiation of He ions with the energy of 300 keV were investigated, and were compared with that of the tungsten. The results show that after the He{sup 2+} irradiation, metallic glass Fe{sub 68}Zr{sub 7}B{sub 25} still maintained amorphous. While a small amount of metastable β-Mn type phase nanocrystals formed in metallic glass Fe{sub 80}Si{sub 7.43}B{sub 12.57} at the fluence of 4.0 × 10{sup 17}ions/cm{sup 2} (19dpa). The nanocrystals transformed into α-Fe phase and tetragonal Fe{sub 2}B phase as the fluence increased to 1.0 × 10{sup 18}ions/cm{sup 2} (47dpa). Then the new orthogonal Fe{sub 3}B phase and β-Mn type phase nanocrystals appeared when the fluence increased further, and the quantities of nanocrystals increased. Blisters and cracks appeared on the surface of tungsten under the irradiation fluence of 1.0 × 10{sup 18}ions/cm{sup 2}, however only when the fluence was up to 1.6 × 10{sup 18}ions/cm{sup 2}, could cracks and spalling appear on the surfaces of metallic glasses. - Highlights: •Metallic glass Fe{sub 68}Zr{sub 7}B{sub 25} could maintain amorphous state after the irradiation. •A series of crystallization behaviors occurred in metallic glass Fe{sub 80}Si{sub 7.43}B{sub 12.57}. •The surface of tungsten appeared blisters at the fluence of 1.0 × 10{sup 18} ions/cm{sup 2}. •Surfaces of Fe-based metallic glasses cracked at the fluence of 1.6 × 10{sup 18}ions/cm{sup 2}.

Phenomenological approach to the spin glass state of (Cu-Mn, Ag-Mn, Au-Mn and Au-Fe) alloys at low temperatures

International Nuclear Information System (INIS)

Al-Jalali, Muhammad A.; Kayali, Fawaz A.

2000-01-01

Full text.The spin glass of: (Cu-Mn, Ag-Mn, Au-Mn, Au-Fe) alloys has been extensively studied. The availability of published and assured experimental data on the susceptibility x(T) of this alloys has enabled the design and application of phenomenological approach to the spin glass state of these interesting alloys. The use of and advanced (S.P.S.S) computer software has resulted revealing some important features of the spin glass in these alloys, the most important of which is that the spin glass state do not represent as phase change

Structure and dynamics of hydrated Fe(II) and Fe(III) ions. Quantum mechanical and molecular mechanical simulations

International Nuclear Information System (INIS)

Remsungnen, T.

2002-11-01

Classical molecular dynamics (MD) and combined em ab initio quantum mechanical/molecular mechanical molecular dynamics (QM/MM-MD) simulations have been performed to investigate structural, dynamical and energetical properties of Fe(II), and Fe(III) transition metal ions in aqueous solution. In the QM/MM-MD simulations the ion and its first hydration sphere were treated at the Hartree-Fock ab initio quantum mechanical level, while ab initio generated pair plus three-body potentials were employed for the remaining system. For the classical MD simulation the pair plus three-body potential were employed for all ion-water interactions. The coordination number of the first hydration shell is 100 % of 6 in both cases. The number of waters in the second hydration shell obtained from classical simulations are 13.4 and 15.1 for Fe(II) and Fe(III), respectively, while QM/MM-MD gives the values of 12.4 and 13.4 for Fe(II) and Fe(III). The energies of hydration obtained from MD and QM/MM-MD for Fe(II) are 520 and 500 kcal/mol, and for Fe(III) 1160 and 1100 kcal/mol respectively. The mean residence times of water in the second shell obtained from QM/MM-MD are 24 and 48 ps for Fe(II) and Fe(III), respectively. In contrast to the data obtained from classical MD simulation, the QM/MM-MD values are all in good agreement with the experimental data available. These investigations and results clearly indicate that many-body effects are essential for the proper description of all properties of the aqueous solution of both Fe(II) and Fe(III) ions. (author)

Rambutan-like FeCO3 hollow microspheres: facile preparation and superior lithium storage performances.

Science.gov (United States)

Zhong, Yiren; Su, Liwei; Yang, Mei; Wei, Jinping; Zhou, Zhen

2013-11-13

Rambutan-like FeCO3 hollow microspheres were prepared via a facile and economic one-step hydrothermal method. The structure and morphology evolution mechanism was disclosed through time-dependent experiments. After undergoing the symmetric inside-out Ostwald ripening, the resultants formed microporous/nanoporous constructions composed of numerous one-dimensional (1D) nanofiber building blocks. Tested as anode materials of Li-ion batteries, FeCO3 hollow microspheres presented attractive electrochemical performances. The capacities were over 1000 mAh g(-1) for initial charge, ~880 mAh g(-1) after 100 cycles at 50 mA g(-1), and ~710 mAh g(-1) after 200 cycles at 200 mA g(-1). The 1D nanofiber assembly and hollow interior endow this material efficient contact with electrolyte, short Li(+) diffusion paths, and sufficient void spaces to accommodate large volume variation. The cost-efficient FeCO3 with rationally designed nanostructures is a promising anode candidate for Li-ion batteries.

Microstructural changes in silicon induced by patterning with focused ion beams of Ga, Si and Au

International Nuclear Information System (INIS)

Chee, See Wee; Kammler, Martin; Balasubramanian, Prabhu; Reuter, Mark C.; Hull, Robert; Ross, Frances M.

2013-01-01

We use focused beams of Ga + , Au + and Si ++ ions to induce local microstructural changes in single crystal silicon. The ions were delivered as single spot pulses into thin Si membranes that could subsequently be imaged and annealed in situ in a transmission electron microscope. For each ion, the focused ion beam implantation created an array of amorphous regions in the crystalline membrane. Annealing causes solid phase epitaxial regrowth to take place, but we show that the resulting microstructure depends on the ion species. For Ga + and Au + , precipitates remain after recrystallization, while for Si ++ , dislocation loops form around the periphery of each implanted spot. We attribute these loops to defects formed during solid phase epitaxial regrowth, with controlled placement of the loops possible. - Highlights: ► Ga + , Au + and Si ++ were implanted into thin membranes of Si. ► Samples were imaged and annealed in situ in a transmission electron microscope. ► Focused ion beam implantation created an array of amorphous spots. ► After recrystallization, precipitates form for Ga + and Au + , dislocation loops for Si ++ . ► Controlled placement of the dislocation loops possible

Ion exchange and electrochemical evaluation of the microporous phosphate Li9Fe7(PO4)10

International Nuclear Information System (INIS)

Becht, Gregory A.; Vaughey, John T.; Britt, Robin L.; Eagle, Cassandra T.; Hwu, Shiou-Jyh

2008-01-01

A new lithium iron(III) phosphate, Li 9 Fe 7 (PO 4 ) 10 , has been synthesized and is currently under electrochemical evaluation as an anode material for rechargeable lithium-ion battery applications. The sample was prepared via the ion exchange reaction of Cs 5 K 4 Fe 7 (PO 4 ) 10 1 in the 1 M LiNO 3 solution under hydrothermal conditions at 200 deg. C. The fully Li + -exchanged sample Li 9 Fe 7 (PO 4 ) 10 2 cannot yet be synthesized by conventional high-temperature, solid-state methods. The parent compound 1 is a member of the Cs 9-x K x Fe 7 (PO 4 ) 10 series that was previously isolated from a high-temperature (750 deg. C) reaction employing the eutectic CsCl/KCl molten salt. The polycrystalline solid 1 was first prepared in a stoichiometric reaction via conventional solid-state method then followed by ion exchange giving rise to 2. Both compounds adopt three-dimensional structures that consist of orthogonally interconnected channels where electropositive ions reside. It has been demonstrated that the Cs 9-x K x Fe 7 (PO 4 ) 10 series possesses versatile ion exchange capabilities with all the monovalent alkali metal and silver cations due to its facile pathways for ion transport. 1 and 2 were subject to electrochemical analysis and preliminary results suggest that the latter can be considered as an anode material. Electrochemical results indicate that Li 9 Fe 7 (PO 4 ) 10 is reduced below 1 V (vs. Li) to most likely form a Fe(0)/Li 3 PO 4 composite material, which can subsequently be cycled reversibly at relatively low potential. An initial capacity of 250 mAh/g was measured, which is equivalent to the insertion of thirteen Li atoms per Li 9+x Fe 7 (PO 4 ) 10 (x = 13) during the charge/discharge process (Fe 2+ + 2e → Fe 0 ). Furthermore, 2 shows a lower reduction potential (0.9 V), by approximately 200 mV, and much better electrochemical reversibility than iron(III) phosphate, FePO 4 , highlighting the value of improving the ionic conductivity of the sample

Anomalous random correlations of force constants on the lattice dynamical properties of disordered Au-Fe alloys

Science.gov (United States)

Kangsabanik, Jiban; Chouhan, Rajiv K.; Johnson, D. D.; Alam, Aftab

2017-09-01

Gold iron (Au-Fe) alloys are of immense interest due to their biocompatibility, anomalous Hall conductivity, and applications in various medical treatments. However, irrespective of the method of preparation, they often exhibit a high level of disorder with properties sensitive to the thermal or magnetic annealing temperatures. We calculate the lattice dynamical properties of Au1 -xFex alloys using density functional theory methods where, being multisite properties, reliable interatomic force constant (IFC) calculations in disordered alloys remain a challenge. We follow a twofold approach: (1) an accurate IFC calculation in an environment with nominally zero chemical pair correlations to mimic the homogeneously disordered alloy and (2) a configurational averaging for the desired phonon properties (e.g., dispersion, density of states, and entropy). We find an anomalous change in the IFC's and phonon dispersion (split bands) near x =0.19 , which is attributed to the local stiffening of the Au-Au bonds when Au is in the vicinity of Fe. Other results based on mechanical and thermophysical properties reflect a similar anomaly: Phonon entropy, e.g., becomes negative below x =0.19 , suggesting a tendency for chemical unmixing, reflecting the onset of a miscibility gap in the phase diagram. Our results match fairly well with reported data wherever available.

Ion scattering studies of ordered alloy surfaces: CuAu(1 0 0) and NiAl

International Nuclear Information System (INIS)

Beikler, R.; Taglauer, E.

2000-01-01

The composition and structure of alloy surfaces can differ from the corresponding bulk properties due to segregation and relaxation effects. We studied the (1 0 0) surface of the ordered alloy CuAu and amorphous Ni and Al by low-energy Ne + and Na + ion scattering. The interpretation of the experimental results is supported by numerical simulations using the MARLOWE code. In the CuAu system a certain geometry was found to be very sensitive to Au presence in the 2nd layer. Comparison with MARLOWE results also allows to study variations in the ion yields arising from neutralization effects. By trajectory analysis ion survival probabilities are estimated for Ni and Al

Structure of Fe(III) precipitates generated by Fe(0) electrocoagulation in the presence of groundwater ions

Science.gov (United States)

van Genuchten, C. M.; Pena, J.; Addy, S. E.; Gadgil, A. J.

2012-12-01

Electrocoagulation (EC) using Fe(0) electrodes is an inexpensive and efficient technology capable of removing a variety of contaminants from water supplies. Because of its ease of use and modest electricity and Fe(0) requirements, EC has potential as an arsenic-removal technology for rural South Asia, where millions drink groundwater contaminated by arsenic. In EC, a small external voltage applied to a sacrificial Fe(0) anode in contact with an electrolyte (e.g. pumped groundwater containing arsenic) promotes the oxidative dissolution of Fe ions, which polymerize and create reactive hydrous ferric oxides (HFO) in-situ with a high affinity for binding contaminants. The chemical composition of the electrolyte influences EC performance. For example, major inorganic ions present in groundwater (e.g. Ca, Mg, P, As(V), Si) alter the pathway by which FeO6 oligomers polymerize to form crystalline Fe (oxyhydr)oxide minerals. Because the precipitate structure largely determines properties that govern the efficiency of EC systems (e.g. precipitate reactivity and colloidal stability), it is essential to understand the individual and interdependent structural effects of common groundwater ions. In this work, we integrate Fe K-edge EXAFS spectroscopy with the Pair Distribution Function (PDF) technique to create a detailed description of EC precipitate structure as a function of electrolyte chemistry. EC precipitate samples were generated in a range of individual and combined concentrations of Ca, Mg, P, As(V), and Si, encompassing most of the typical levels found in natural groundwater. Combining complementary EXAFS and PDF techniques with batch uptake experiments and general chemical reasoning, we obtain structural representations of EC precipitates that are inaccessible with any single characterization technique. Our results indicate that the presence of As(V), P, and Si oxyanions promote the formation of nanoscale material bearing similar, but not identical, intermediate

Multifunctional Fe3O4 @ Au core/shell nanostars: a unique platform for multimode imaging and photothermal therapy of tumors

Science.gov (United States)

Hu, Yong; Wang, Ruizhi; Wang, Shige; Ding, Ling; Li, Jingchao; Luo, Yu; Wang, Xiaolin; Shen, Mingwu; Shi, Xiangyang

2016-01-01

We herein report the development of multifunctional folic acid (FA)-targeted Fe3O4 @ Au nanostars (NSs) for targeted multi-mode magnetic resonance (MR)/computed tomography (CT)/photoacoustic (PA) imaging and photothermal therapy (PTT) of tumors. In this present work, citric acid-stabilized Fe3O4/Ag composite nanoparticles prepared by a mild reduction route were utilized as seeds and exposed to the Au growth solution to induce the formation of Fe3O4 @ Au core/shell NSs. Followed by successive decoration of thiolated polyethyleneimine (PEI-SH), FA via a polyethylene glycol spacer, and acetylation of the residual PEI amines, multifunctional Fe3O4 @ Au NSs were formed. The designed multifunctional NSs possess excellent colloidal stability, good cytocompatibility in a given concentration range, and specific recognition to cancer cells overexpressing FA receptors. Due to co-existence of Fe3O4 core and star-shaped Au shell, the NSs can be used for MR and CT imaging of tumors, respectively. Likewise, the near infrared plasmonic absorption feature also enables the NSs to be used for PA imaging and PTT of tumors. Our study clearly demonstrates a unique theranostic nanoplatform that can be used for high performance multi-mode imaging-guided PTT of tumors, which may be extendable for theranostics of different diseases in translational medicine. PMID:27325015

Synthesis of Au nanoparticles at the surface and embedded in carbonaceous matrix by 150 keV Ar ion irradiation

International Nuclear Information System (INIS)

Prakash, Jai; Tripathi, Jalaj; Tripathi, A; Kumar, P; Asokan, K; Avasthi, D K; Rigato, V; Pivin, J C; Chae, Keun Hwa; Gautam, Sanjeev

2011-01-01

We report on synthesis of spherical Au nanoparticles at the surface and embedded in carbonaceous matrix by 150 keV Ar ion irradiation of thin Au film on polyethyleneterepthlate (PET). The pristine and irradiated samples are characterized by Rutherford backscattering spectrometry (RBS), atomic force microscopy, scanning electron microscopy and transmission electron microscopy (TEM) techniques. RBS spectra reveal the sputtering of Au film and interface mixing, increasing with increasing fluence. Surface morphology shows that at the fluence of 5 x 10 15 ions cm -2 , dewetting of thin Au film begins and partially connected nanostructures are formed whereas, at the higher fluence of 5 x 10 16 ions cm -2 , isolated spherical Au nanoparticles (45 ± 20 nm) are formed at the surface. Cross-sectional TEM observations also evidence the Au nanoparticles at the surface and mixed metal-polymer region indicating the formation of nanocomposites with small Au nanoparticles. The results are explained by the crater formation, sputtering followed by dewetting of the thin Au film and interdiffusion at the interface, through molten zones due to thermal spike induced by Ar ions.

Post-annealing recrystallization and damage recovery process in Fe ion implanted Si

International Nuclear Information System (INIS)

Naito, Muneyuki; Hirata, Akihiko; Ishimaru, Manabu; Hirotsu, Yoshihiko

2007-01-01

We have investigated ion-beam-induced and thermal annealing-induced microstructures in high fluence Fe implanted Si using transmission electron microscopy. Si(1 1 1) substrates were irradiated with 120 keV Fe ions at 120 K to fluences of 0.4 x 10 17 and 4.0 x 10 17 cm -2 . A continuous amorphous layer was formed on Si substrates in both as-implanted samples. After thermal annealing at 1073 K for 2 h, β-FeSi 2 fine particles buried in a polycrystalline Si layer were observed in the low fluence sample, while a continuous β-FeSi 2 layer was formed in the high fluence sample. We discuss the relationship between ion fluence and defects recovery process in Fe ion implanted Si

Spectroscopic properties of Fe2+ ions at tetragonal sites-Crystal field effects and microscopic modeling of spin Hamiltonian parameters for Fe2+ (S=2) ions in K2FeF4 and K2ZnF4

International Nuclear Information System (INIS)

Rudowicz, C.; Piwowarska, D.

2011-01-01

Magnetic and spectroscopic properties of the planar antiferromagnet K 2 FeF 4 are determined by the Fe 2+ ions at tetragonal sites. The two-dimensional easy-plane anisotropy exhibited by K 2 FeF 4 is due to the zero field splitting (ZFS) terms arising from the orbital singlet ground state of Fe 2+ ions with the spin S=2. To provide insight into the single-ion magnetic anisotropy of K 2 FeF 4 , the crystal field theory and the microscopic spin Hamiltonian (MSH) approach based on the tensor method is adopted. Survey of available experimental data on the crystal field energy levels and free-ion parameters for Fe 2+ ions in K 2 FeF 4 and related compounds is carried out to provide input for microscopic modeling of the ZFS parameters and the Zeeman electronic ones. The ZFS parameters are expressed in the extended Stevens notation and include contributions up to the fourth-order using as perturbation the spin-orbit and electronic spin-spin couplings within the tetragonal crystal field states of the ground 5 D multiplet. Modeling of the ZFS parameters and the Zeeman electronic ones is carried out. Variation of these parameters is studied taking into account reasonable ranges of the microscopic ones, i.e. the spin-orbit and spin-spin coupling constants, and the energy level splittings, suitable for Fe 2+ ions in K 2 FeF 4 and Fe 2+ :K 2 ZnF 4 . Conversions between the ZFS parameters in the extended Stevens notation and the conventional ones are considered to enable comparison with the data of others. Comparative analysis of the MSH formulas derived earlier and our more complete ones indicates the importance of terms omitted earlier as well as the fourth-order ZFS parameters and the spin-spin coupling related contributions. The results may be useful also for Fe 2+ ions at axial symmetry sites in related systems, i.e. Fe:K 2 MnF 4 , Rb 2 Co 1-x Fe x F 4 , Fe 2+ :Rb 2 CrCl 4 , and Fe 2+ :Rb 2 ZnCl 4 . - Highlights: → Truncated zero field splitting (ZFS) terms for Fe 2+ in K

Ion-beam mixing and tribology of Fe/B multilayers

International Nuclear Information System (INIS)

Hu, R.; Rehn, L.E.; Baldo, P.M.; Fenske, G.R.

1990-01-01

This paper reports the interdiffusion of Fe and B trilayer specimens during 1-MeV Kr + bombardment studied using Rutherford backscattering and electron microscopy. The square of the interdiffusion distance during mixing at 300 degrees C was found to depend linearly on the irradiation dose. Arrhenius behavior with an apparent activation enthalpy of 0.7 eV was observed for the mixing between 200 and 500 degrees C. Electron microscopy of ion-beam mixed multilayer specimens revealed that two crystalline compounds, Fe 2 B and Fe 3 B, formed during bombardment at 450 degrees C, while two different amorphous Fe/B phases formed at 300 degrees C. Substantially improved adhesion and reduced friction were observed for Fe/B multilayers ion-beam mixed onto M50 steel substrates at 450 degrees C

On acceleration of <1 MeV/n He ions in the corotating compression regions near 1 AU: STEREO observations

Directory of Open Access Journals (Sweden)

R. Bučík

2009-09-01

Full Text Available Observations of multi-MeV corotating interaction region (CIR ions are in general consistent with models of CIR shock acceleration and transport. The presence of suprathermal particles near 1 AU in unshocked compression regions is not adequately explained. Nonetheless, more recent works demonstrate that unshocked compression regions associated with CIRs near 1 AU could energize particles. In the energy range from ~0.1 to ~1 MeV/n we investigate CIR events observed in 2007–2008 by the STEREO A and B spacecraft. We treat the predictions of compression acceleration by comparing the observed ion intensities with the model parameters. These observations show that the ion intensity in CIR events with in-situ reverse shock is well organized by the parameters which characterize the compression region itself, like compression width, solar wind speed gradients and the total pressure. In turn, for CIR events with the absence of the shocks the model predictions are not fulfilled.

Fe(III/TiO2-Montmorillonite Photocatalyst in Photo-Fenton-Like Degradation of Methylene Blue

Directory of Open Access Journals (Sweden)

Is Fatimah

2015-01-01

Full Text Available A photodegradation process of methylene blue (MB in aqueous solution using Fe(III/TiO2-montmorillonite photocatalyst is presented. The photocatalyst material was prepared using Indonesian natural montmorillonite in TiO2 pillarization process followed by Fe(III ion exchange. Kinetic study on MB degradation was conducted and evaluated by three kinetic models: the pseudo-first- and second-order equations and the Elovich equation. From the results, it is concluded that the degradation under the photo-Fenton-like process utilizing Fe(III/TiO2-montmorillonite photocatalyst conformed to the Elovich kinetic model.

Binding Affinity of a Highly Sensitive Au/Ag/Au/Chitosan-Graphene Oxide Sensor Based on Direct Detection of Pb2+ and Hg2+ Ions

Directory of Open Access Journals (Sweden)

Nur Hasiba Kamaruddin

2017-10-01

Full Text Available The study of binding affinity is essential in surface plasmon resonance (SPR sensing because it allows researchers to quantify the affinity between the analyte and immobilised ligands of an SPR sensor. In this study, we demonstrate the derivation of the binding affinity constant, K, for Pb2+ and Hg2+ ions according to their SPR response using a gold/silver/gold/chitosan–graphene oxide (Au/Ag/Au/CS–GO sensor for the concentration range of 0.1–5 ppm. The higher affinity of Pb2+ to binding with the CS–GO sensor explains the outstanding sensitivity of 2.05 °ppm−1 against 1.66 °ppm−1 of Hg2+. The maximum signal-to-noise ratio (SNR upon detection of Pb2+ is 1.53, and exceeds the suggested logical criterion of an SNR. The Au/Ag/Au/CS–GO SPR sensor also exhibits excellent repeatability in Pb2+ due to the strong bond between its functional groups and this cation. The adsorption data of Pb2+ and Hg2+ on the CS–GO sensor fits well with the Langmuir isotherm model where the affinity constant, K, of Pb2+ and Hg2+ ions is computed. The affinity of Pb2+ ions to the Au/Ag/Au/CS–GO sensor is significantly higher than that of Hg2+ based on the value of K, 7 × 105 M−1 and 4 × 105 M−1, respectively. The higher shift in SPR angles due to Pb2+ and Hg2+ compared to Cr3+, Cu2+ and Zn2+ ions also reveals the greater affinity of the CS–GO SPR sensor to them, thus supporting the rationale for obtaining K for these two heavy metals. This study provides a better understanding on the sensing performance of such sensors in detecting heavy metal ions.

Gold nano-particle formation from crystalline AuCN: Comparison of thermal, plasma- and ion-beam activated decomposition

Energy Technology Data Exchange (ETDEWEB)

Beck, Mihály T.; Bertóti, Imre, E-mail: bertoti.imre@ttk.mta.hu; Mohai, Miklós; Németh, Péter; Jakab, Emma; Szabó, László; Szépvölgyi, János

2017-02-15

In this work, in addition to the conventional thermal process, two non-conventional ways, the plasma and ion beam activations are described for preparing gold nanoparticles from microcrystalline AuCN precursor. The phase formation at plasma and ion beam treatments was compared with that at thermal treatments and the products and transformations were characterized by thermogravimetry-mass-spectrometry (TG-MS), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). TG-MS measurements in Ar atmosphere revealed that AuCN decomposition starts at 400 °C and completes at ≈700 °C with evolution of gaseous (CN){sub 2}. XPS and TEM show that in heat treatment at 450 °C for 1 h in Ar, loss of nitrogen and carbon occurs and small, 5–30 nm gold particles forms. Heating at 450 °C for 10 h in sealed ampoule, much larger, 60–200 nm size and well faceted Au particles develop together with a fibrous (CN){sub n} polymer phase, and the Au crystallites are covered by a 3–5 nm thick polymer shell. Low pressure Ar plasma treatment at 300 eV energy results in 4–20 nm size Au particles and removes most of the nitrogen and part of carbon. During Ar{sup +} ion bombardment with 2500 eV energy, 5–30 nm size Au crystallites form already in 10 min, with preferential loss of nitrogen and with increased amount of carbon residue. The results suggest that plasma and ion beam activation, acting similarly to thermal treatment, may be used to prepare Au nanoparticles from AuCN on selected surface areas either by depositing AuCN precursors on selected regions or by focusing the applied ionized radiation. Thus they may offer alternative ways for preparing tailor-made catalysts, electronic devices and sensors for different applications. - Graphical abstract: Proposed scheme of the decomposition mechanism of AuCN samples: heat treatment in Ar flow (a) and in sealed ampoule (b); Ar{sup +} ion treatment at 300 eV (c) and at 2500 eV (d). Cross section sketches

Surface sputtering in high-dose Fe ion implanted Si

International Nuclear Information System (INIS)

Ishimaru, Manabu

2007-01-01

Microstructures and elemental distributions in high-dose Fe ion implanted Si were characterized by means of transmission electron microscopy and Rutherford backscattering spectroscopy. Single crystalline Si(0 0 1) substrates were implanted at 350 deg. C with 120 keV Fe ions to fluences ranging from 0.1 x 10 17 to 4.0 x 10 17 /cm 2 . Extensive damage induced by ion implantation was observed inside the substrate below 1.0 x 10 17 /cm 2 , while a continuous iron silicide layer was formed at 4.0 x 10 17 /cm 2 . It was found that the spatial distribution of Fe projectiles drastically changes at the fluence between 1.0 x 10 17 and 4.0 x 10 17 /cm 2 due to surface sputtering during implantation

Analysis of the intermediate stage in the heavy ion interactions of 208Pb+197Au and 197Au+197Au

International Nuclear Information System (INIS)

Nasir, Tabassum; Khan, E.U.; Baluch, J.J.; Qureshi, I.E.; Sajid, M.; Shahzad, M.I.

2008-01-01

Two different projectiles 208 Pb and 197 Au at the same energy (11.67MeV/u) have been bombarded on 197 Au target to study heavy ion interactions using mica as a passive detector. In this paper we present results on the study of energy damping and time scale of the existence of di-nuclear composite system in the intermediate reaction step. The plots of Q-values as well as reaction cross sections in various angular bins of scattering angles suggest that K.E. damping was complete and dynamic equilibrium was established between the first and second reaction steps. The time scale of this duration was also determined

Transient field for W ions traversing Fe hosts and for Os ions traversing Fe and Ni hosts

International Nuclear Information System (INIS)

Stuchbery, A.E.; Bolotin, H.H.; Doran, C.E.

1987-02-01

Transient field strengths were measured for 184 W and 186 W ions traversing thin, magnetized Fe foils with velocities in the range 1.8 ≤ v/v>=o ≤ 5.7 (v>=o Bohr velocity) and for 188 Os, 190 Os, 192 Os ions traversing polarized Ni hosts with average velocities =o> ∼ 4. The present measured transient field strengths, together with previously measured results for W, Os ions, are compared with transient-field strength parametrizations, and discussed in terms of microscopic models of the transient field

Adsorption of Nitrite and Nitrate Ions from an Aqueous Solution by Fe-Mg-Type Hydrotalcites at Different Molar Ratios.

Science.gov (United States)

Ogata, Fumihiko; Nagai, Noriaki; Kariya, Yukine; Nagahashi, Eri; Kobayashi, Yuhei; Nakamura, Takehiro; Kawasaki, Naohito

2018-01-01

In this study, we prepared Fe-Mg-type hydrotalcites (Fe-HT3.0 and Fe-HT5.0) with different molar ratios and evaluated their adsorption capability for nitrite and nitrate ions from aqueous solution. Fe-HT is a typical hydrotalcite-like layered double hydroxide. Adsorption isotherms, as well as the effects of contact time and pH were investigated, and it was found that Fe-HT can adsorb larger amounts of nitrite and nitrate ions than Al-HT (normal-type hydrotalcite). Adsorption isotherm data were fitted to both Freundlich (correlation coefficient: 0.970-1.000) and Langmuir (correlation coefficient: 0.974-0.999) equations. Elemental analysis and binding energy of Fe-HT surface before and after adsorption indicated that the adsorption mechanism was related to the interaction between the adsorbent surface and anions. In addition, the ion exchange process is related to the adsorption mechanism. The adsorption amount increased with increasing temperature (7-25°C). The experimental data fit the pseudo-second-order model better than the pseudo-first-order model. The effect of pH on adsorption was not significant, which suggested that Fe-HT could be used over a wide pH range (4-12). These results indicate that Fe-HT is a good adsorbent for the removal of nitrite and nitrate ions from aqueous solution.

The sandwich-type electrochemiluminescence immunosensor for {alpha}-fetoprotein based on enrichment by Fe{sub 3}O{sub 4}-Au magnetic nano probes and signal amplification by CdS-Au composite nanoparticles labeled anti-AFP

Energy Technology Data Exchange (ETDEWEB)

Zhou Hankun [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Material Science and Chemical Engineering of Ningbo University, Ningbo 315211 (China); Gan Ning, E-mail: ganning@nbu.edu.cn [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Material Science and Chemical Engineering of Ningbo University, Ningbo 315211 (China); Li Tianhua; Cao Yuting; Zeng Saolin [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Material Science and Chemical Engineering of Ningbo University, Ningbo 315211 (China); Zheng Lei, E-mail: nfyyzl@163.com [Department of Laboratory Medicine, Nanfang Hospital, Southern Medical University, Guangzhou 510515 (China); Guo Zhiyong [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Material Science and Chemical Engineering of Ningbo University, Ningbo 315211 (China)

2012-10-09

Highlights: Black-Right-Pointing-Pointer Sandwich immunoreaction, testing a large number of samples simultaneously. Black-Right-Pointing-Pointer The magnetic separation and enrichment by Fe{sub 3}O{sub 4}-Au magnetic nano probes. Black-Right-Pointing-Pointer The amplification of detection signal by CdS-Au composite nanoparticles labeled anti-AFP. Black-Right-Pointing-Pointer Almost no background signal, which greatly improve the sensitivity of detection. - Abstract: A novel and sensitive sandwich-type electrochemiluminescence (ECL) immunosensor was fabricated on a glassy carbon electrode (GCE) for ultra trace levels of {alpha}-fetoprotein (AFP) based on sandwich immunoreaction strategy by enrichment using magnetic capture probes and quantum dots coated with Au shell (CdS-Au) as the signal tag. The capture probe was prepared by immobilizing the primary antibody of AFP (Ab1) on the core/shell Fe{sub 3}O{sub 4}-Au nanoparticles, which was first employed to capture AFP antigens to form Fe{sub 3}O{sub 4}-Au/Ab1/AFP complex from the serum after incubation. The product can be separated from the background solution through the magnetic separation. Then the CdS-Au labeled secondary antibody (Ab2) as signal tag (CdS-Au/Ab2) was conjugated successfully with Fe{sub 3}O{sub 4}-Au/Ab1/AFP complex to form a sandwich-type immunocomplex (Fe{sub 3}O{sub 4}-Au/Ab1/AFP/Ab2/CdS-Au), which can be further separated by an external magnetic field and produce ECL signals at a fixed voltage. The signal was proportional to a certain concentration range of AFP for quantification. Thus, an easy-to-use immunosensor with magnetic probes and a quantum dots signal tag was obtained. The immunosensor performed at a level of high sensitivity and a broad concentration range for AFP between 0.0005 and 5.0 ng mL{sup -1} with a detection limit of 0.2 pg mL{sup -1}. The use of magnetic probes was combined with pre-concentration and separation for trace levels of tumor markers in the serum. Due to the

Effects of coating molecules on the magnetic heating properties of Au-Fe3O4 heterodimer nanoparticles

Science.gov (United States)

Yamamoto, Y.; Ogasawara, J.; Himukai, H.; Itoh, T.

2016-10-01

In this paper, we report the heating properties of gold-magnetite (Au-Fe3O4) heterodimer nanoparticles (NPs) subjected to an alternating magnetic field. The Au-Fe3O4 NPs coated with oleic acid and oleylamine (OA) were synthesized through a method that combines seed mediation and high-temperature decomposition. The coating was replaced with dimercaptosuccinic acid (DMSA) by the ligand-exchange method. The specific absorption rates (SARs) for the OA- and DMSA-coated Au-Fe3O4 NPs coated with OA and DMSA at room temperature were determined through the calorimetric and magnetometric methods. SAR depended on the square of the magnetic field H up to an H value of 4 kA/m. The absolute value of the SAR for DMSA-coated NPs is about fivefold higher than that of the OA-coated NPs. The AC magnetic hysteresis measurements showed the recovery of the magnetic volume and the decrease in the magnetic anisotropy of the DMSA-coated NPs relative to those of the OA-coated NPs. These results suggest that the protective agent influences the magnetic properties of magnetite NPs via gold NPs.

Production of highly charged ion beams from ECR ion sources

International Nuclear Information System (INIS)

Xie, Z.Q.

1997-09-01

Electron Cyclotron Resonance (ECR) ion source development has progressed with multiple-frequency plasma heating, higher mirror magnetic fields and better technique to provide extra cold electrons. Such techniques greatly enhance the production of highly charged ions from ECR ion sources. So far at cw mode operation, up to 300 eμA of O 7+ and 1.15 emA of O 6+ , more than 100 eμA of intermediate heavy ions for charge states up to Ar 13+ , Ca 13+ , Fe 13+ , Co 14+ and Kr 18+ , and tens of eμA of heavy ions with charge states to Kr 26+ , Xe 28+ , Au 35+ , Bi 34+ and U 34+ have been produced from ECR ion sources. At an intensity of at least 1 eμA, the maximum charge state available for the heavy ions are Xe 36+ , Au 46+ , Bi 47+ and U 48+ . An order of magnitude enhancement for fully stripped argon ions (I ≥ 60 enA) also has been achieved. This article will review the ECR ion source progress and discuss key requirement for ECR ion sources to produce the highly charged ion beams

Investigation of the effect of the incorporated Fe atoms in the ion-beam induced nanopatterns on Si(001)

Energy Technology Data Exchange (ETDEWEB)

Khanbabaee, Behnam; Biermanns, Andreas; Pietsch, Ullrich [Siegen Univ. (Germany). Festkoerperphysik; Cornejo, Marina; Frost, Frank [Leibniz-Institute fuer Oberflaechenmodifizierung e.V. (IOM), Leipzig (Germany)

2012-07-01

Ion beam erosion of semiconductor surfaces can modify the surface and depends on main sputtering parameters; different surface topographies such as ripple or dot like pattern are fabricated on the surface. Recent experiments have shown that the incorporation of foreign metallic atoms during the sputtering process plays a crucial role in pattern formation on surfaces. In the result of investigation we report on the depth profile of Fe atoms incorporated in sputtering process on Si(100) with low energy Kr ion beam. X-ray reflectivity (XRR) measurements determine the concentration profile of Fe atoms. X-ray absorption near edge spectroscopy (XANES) at the Fe K-edge (7112 eV) shows the formation of Fe rich silicide near surface region. X-ray photoelectron spectroscopy (XPS) shows a shift in the binding energy of Si2p levels at the surface compared top bulk confirming the formation of different phases of Fe-silicide on tope and below the surface. The depth profiles obtained by XRR are compared to results obtained by complementary secondary-ion mass spectrometry (SIMS).

Structural and magnetic properties of Fe-Al silica composites prepared by sequential ion implantation

International Nuclear Information System (INIS)

Julian Fernandez, C. de; Tagliente, M.A.; Mattei, G.; Sada, C.; Bello, V.; Maurizio, C.; Battaglin, G.; Sangregorio, C.; Gatteschi, D.; Tapfer, L.; Mazzoldi, P.

2004-01-01

The nanostructural and magnetic properties of Fe-Al/SiO 2 granular solids prepared by ion implantation have been investigated. A strong effect of the implantation order of the Fe and Al ions has been evidenced. By implanting first the Al ions and later Fe ions, 5-40 nm core-shell nanoparticles are formed with a magnetic behavior similar to that of Fe. The lattice parameter of the nanoparticles is consistent with that of the α-Fe. By changing the implantation order, 10-15 nm core-shell nanoparticles of a bcc Fe-based phase with a lattice 2.5% smaller than that of α-Fe are formed. The temperature dependence of the magnetization indicates a superparamagnetic behavior

Structural and magnetic properties of Fe-Al silica composites prepared by sequential ion implantation

Energy Technology Data Exchange (ETDEWEB)

Julian Fernandez, C. de E-mail: dejulian@padova.infm.it; Tagliente, M.A.; Mattei, G.; Sada, C.; Bello, V.; Maurizio, C.; Battaglin, G.; Sangregorio, C.; Gatteschi, D.; Tapfer, L.; Mazzoldi, P

2004-02-01

The nanostructural and magnetic properties of Fe-Al/SiO{sub 2} granular solids prepared by ion implantation have been investigated. A strong effect of the implantation order of the Fe and Al ions has been evidenced. By implanting first the Al ions and later Fe ions, 5-40 nm core-shell nanoparticles are formed with a magnetic behavior similar to that of Fe. The lattice parameter of the nanoparticles is consistent with that of the {alpha}-Fe. By changing the implantation order, 10-15 nm core-shell nanoparticles of a bcc Fe-based phase with a lattice 2.5% smaller than that of {alpha}-Fe are formed. The temperature dependence of the magnetization indicates a superparamagnetic behavior.

Photoionization study of Ne-like K9+, Ca10+, Sc11+, Ti12+, V13+, Cr14+, Mn15+, and Fe16+ ions using the screening constant by unit nuclear charge method

International Nuclear Information System (INIS)

Goyal, Arun; Khatri, Indu; Sow, Malick; Sakho, Ibrahima; Aggarwal, Sunny; Singh, A.K.; Mohan, Man

2016-01-01

Photoionization of the 2s 2 2p 6 ( 1 S 0 ) ground state of the Ne-like (Z=19–29) ions is presented in this paper. Resonance energies and total natural width of the 2s2p 6 np 1 P series of the Ne-like K 9+ , Ca 10+ , Sc 11+ , Ti 12+ , V 13+ , Cr 14+ , Mn 15+ , and Fe 16+ are reported. All the calculations are made using the Screening constant by unit nuclear charge (SCUNC) formalism. New data for Ne-like K 9+ , Sc 11+ , Ti 12+ , V 13+ , Cr 14+ , and Mn 15+ ions are tabulated. Good agreements are found with available literature data. - Highlights: • Photoionization of ground state of the Ne-like (Z=19–29) presented. • good agreements with scarce literature data. • New data for Ne-like K 9+ , Sc 11+ , Ti 12+ , V 13+ , Cr 14+ , and Mn 15+ ions. • Useful guidelines for application in laboratory, astrophysics, and plasma physics.

Phase formation in Zr/Fe multilayers during Kr ion irradiation

International Nuclear Information System (INIS)

Motta, A. T.

1998-01-01

A detailed study has been conducted of the effect of Kr ion irradiation on phase formation in Zr-Fe metallic multilayers, using the Intermediate Voltage Electron Microscopy (IVEM) at Argonne National Laboratory. Metallic multilayers were prepared with different overall compositions (near 50-50 and Fe-rich), and with different wavelengths (repetition thicknesses). These samples were irradiated with 300 keV Kr ions at various temperatures to investigate the final products, as well as the kinetics of phase formation. For the shorter wavelength samples, the final product was in all cases an amorphous Zr-Fe phase, in combination with Fe, while specially for the larger wavelength samples, in the Fe-rich samples the intermetallic compounds ZrFe 2 and Zr 3 Fe were formed in addition to the amorphous phase. The dose to full reaction decreases with temperature, and with wavelength in a manner consistent with a diffusion-controlled reaction

Uranium-lead dating of hydrothermal zircon and monazite from the Sin Quyen Fe-Cu-REE-Au-(U) deposit, northwestern Vietnam

Science.gov (United States)

Li, Xiao-Chun; Zhou, Mei-Fu; Chen, Wei Terry; Zhao, Xin-Fu; Tran, MyDung

2018-03-01

The Sin Quyen deposit in northwestern Vietnam contains economic concentrations of Cu, Au and LREE, and sub-economic concentration of U. In this deposit, massive and banded replacement ores are hosted in Neoproterozoic metapelite. The paragenetic sequence includes sodic alteration (stage I), calcic-potassic alteration and associated Fe-REE-(U) mineralization (stage II), Cu-Au mineralization (stage III), and sulfide-(quartz-carbonate) veins (stage IV). The Sin Quyen deposit experienced an extensive post-ore metamorphic overprint, which makes it difficult to precisely determine the mineralization age. In this study, zircon and monazite U-Pb geochronometers and the Rb-Sr isochron method are used to constrain the timing of mineralization. Zircon grains in the ore are closely intergrown or texturally associated with hydrothermal minerals of stage II (e.g., garnet, allanite, and hedenbergite). They may contain primary fluid inclusions and display irregular zoning in cathodoluminescence (CL) images. Zircon grains are rich in U (688 to 2902 ppm) and poor in Th (0.2 to 2.9 ppm). Their δ18OV-SMOW values range from 11.9 to 14.0‰, higher than those of typical magmatic zircon. These textural and compositional features imply that zircon precipitated from 18O- and U-rich hydrothermal fluids, coeval with the minerals of stage II. Monazite occurs in close association with stage II magnetite and allanite and has low contents of Th (<2700 ppm), indicative of a hydrothermal origin. Hydrothermal zircon and monazite have indistinguishable U-Pb ages of 841 ± 12 and 836 ± 18 Ma, respectively, representing the timing of Fe-REE mineralization. There is no direct isotopic constraint on the timing of the Cu-Au mineralization, but geological observations suggest that the Cu-Au and Fe-REE ores most likely formed within a single evolved hydrothermal process. In the plot of 87Rb/86Sr vs. 87Sr/86Sr, the composition of bulk-ore and biotite separates from ore lie along a reference line for 30 Ma

Sequestering of Fe and Pb ions from Wastewater by Canarium ...

African Journals Online (AJOL)

In this paper agricultural waste; Canarium schweinfurthii was explored for the sequestering of Fe and Pb ions from wastewater solution after carbonization and chemical treatment at 400oC. Optimum time of 30 and 150 min with percentage removal of 95 and 98% at optimum pH of 2 and 6 was obtained for Fe and Pb ions.

Influences of Au ion radiation on microstructure and surface-enhanced Raman scattering of nanoporous copper

Science.gov (United States)

Wang, Jing; Hu, Zhaoyi; Li, Rui; Liu, Xiongjun; Xu, Chuan; Wang, Hui; Wu, Yuan; Fu, Engang; Lu, Zhaoping

2018-05-01

In this work, effects of Au ion irradiation on microstructure and surface-enhanced Raman scattering (SERS) performance of nanoporous copper (NPC) were investigated. It is found that the microstructure of NPC could be tailored by the ion irradiation dose, i.e., the pore size decreases while the ligament size significantly coarsens with the increase of the irradiation dose. In addition, the SERS enhancement for rhodamine 6G molecules was improved by Au ions irradiation at an appropriate dose. The underlying mechanism of the increase of SERS enhancement resulted from ion irradiation was discussed. Our findings could provide a new way to tune nanoporosity of nanoporous metals and improve their SERS performance.

Optimization of the composition of bimetallic core/shell Fe{sub 2}O{sub 3}/Au nanoparticles for MRI/CT dual-mode imaging

Energy Technology Data Exchange (ETDEWEB)

Zhang, Song; Qi, Yueyong; Yang, Hua; Gong, Mingfu; Zhang, Dong; Zou, Liguang, E-mail: zlgxqyy@163.com [Third Military Medical University, Department of Radiology, Xinqiao Hospital (China)

2013-11-15

Bimetallic core/shell Fe{sub 2}O{sub 3}/Au nanoparticles are promising candidate dual-mode contrast agents for magnetic resonance imaging (MRI) and computed tomography (CT) imaging. However, the gold coating on the hybrid nanoparticles (hybrids) affects the MRI and CT imaging quality. A thick gold nanoshell increases the X-ray attenuation effect but decreases the magnetic saturation of the hybrids. Therefore, we studied the effect of the Fe{sub 2}O{sub 3} and Au composition on these properties to find a suitable hybrid for MRI and CT imaging. Water-soluble, Au-coated magnetic nanoparticles were synthesized by iteratively reducing Au{sup 3+} onto the Fe{sub 2}O{sub 3} surface via hydroxylamine seeding. The properties of the hybrids obtained after different numbers of Au seeding cycles were studied using transmission electron microscopy, UV–Vis spectrophotometry, a vibrating swatch gaussmeter, MRI, CT, and an MTT assay. The hybrids obtained after three Au seeding cycles had an Fe{sub 2}O{sub 3}:Au molar ratio of 7.2:26.8, a mean diameter of 48.3 nm, a UV–Vis absorbance peak of 550 nm, a saturation magnetization of 49.0 emu/g, and no cytotoxicity at a concentration of 500 μg/mL after incubation with RAW 264.7 cells for up to 72 h. The hybrids obtained after three Au seeding cycles are the preferred candidates for MRI and CT applications because of their relatively high R2 relaxivity (95 mM{sup −1 }s{sup −1}) and X-ray attenuation (1.87 times that of iodine) compared to those of the other hybrids investigated in this study.

Dependence of Au- production upon the target work function in a plasma-sputter-type negative ion source

International Nuclear Information System (INIS)

Okabe, Yushirou; Sasao, Mamiko; Fujita, Junji; Yamaoka, Hitoshi; Wada, Motoi.

1991-01-01

A method to measure the work function of the target surface in a plasma-sputter-type negative ion source has been developed. The method can determine the work function by measuring the photoelectric current induced by two lasers (He-Ne, Ar + laser). The dependence of Au - production upon the work function of the target surface in the ion source was studied using this method. The time variation of the target work function and Au - production rate were measured during the cesium coverage decrease due to the plasma ion sputtering. The observed minimum work function of a cesiated gold surface in an Ar plasma was 1.3 eV. At the same time, the negative ion production rate (Au - current/target current) took the maximum value. The negative ion production rate indicated the same dependence on the incident ion energy as that of the sputtering rate when the work function was constant. (author)

Co-Au core-shell nanocrystals formed by sequential ion implantation into SiO2

International Nuclear Information System (INIS)

Kluth, P.; Hoy, B.; Johannessen, B.; Dunn, S. G.; Foran, G. J.; Ridgway, M. C.

2006-01-01

Co-Au core-shell nanocrystals (NCs) were formed by sequential ion implantation of Au and Co into thin SiO 2 . The NCs were investigated by means of transmission electron microscopy and extended x-ray absorption fine structure spectroscopy. The latter reveals a bond length expansion in the Co core compared to monatomic Co NCs. Concomitantly, a significant contraction of the bond length and a significant reduction of the effective Au-Au coordination number were observed in the Au shells. Increased Debye-Waller factors indicate significant strain in the NCs. These experimental results verify recent theoretical predictions

Hierarchically assembled Au microspheres and sea urchin-like architectures: formation mechanism and SERS study.

Science.gov (United States)

Wang, Xiansong; Yang, Da-Peng; Huang, Peng; Li, Min; Li, Chao; Chen, Di; Cui, Daxiang

2012-12-21

The hierarchically assembled Au microspheres/sea urchin-like structures have been synthesized in aqueous solution at room temperature with and without proteins (bovine serum albumin, BSA) as mediators. The average diameter of an individual Au microsphere is 300-600 nm, which is composed of some compact nanoparticles with an average diameter of about 15 nm. Meanwhile, the sea urchin-like Au architecture exhibits an average diameter of 600-800 nm, which is made up of some nanopricks with an average length of 100-200 nm. These products are characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electronic microscopy (TEM). It is found that the BSA and ascorbic acid (AA) have great effects on the morphology of the resulting products. Two different growth mechanisms are proposed. The study on surface enhanced Raman scattering (SERS) activities is also carried out between Au microspheres and Au sea urchin-like architectures. It is found that Au urchin-like architectures possess much higher SERS activity than the Au microspheres. Our work may shed light on the design and synthesis of hierarchically self-assembled 3D micro/nano-architectures for SERS, catalysis and biosensors.

Electrochemical performance of Fe3O4 micro flower as anode for lithium ion batteries

Science.gov (United States)

Noerochim, Lukman; Anggara, Dika; Susanti, Diah; Subhan, Achmad; Sudaryanto

2018-04-01

Graphite is generally employed in commercial lithium ion batteries which has a specific capacity of 372 mAh/g. In this study, graphite is replaced with carbon-coated magnetite (Fe3O4/C) which has large theoretical specific capacity of 926 mAh/g, environmental friendly, and low cost production. The synthesis of Fe3O4/C is carried out by hydrothermal method with reacting FeCl3 and hexamethylenetetramine (HMT) at temperature variation of 160, 170 and 180°C. The following process is heated by calcination at temperature variations 450, 500 and 550°C. XRD and SEM results show that the as-prepared Fe3O4/C powder has a single phase of Fe3O4 and morphology micro-flowers like with size between 700 nm - 3 µm. CV test results show redox reaction occurs in the voltage range between 0.21-0.85 V and 1.68-1.81 V. The highest specific discharge capacity is obtained 644 mAh/g for specimen with temperature hydrothermal of 170°C and temperature calcination of 550°C. This result shows that Fe3O4/C has a high potential as anode material for lithium ion battery.

Photoionization and electron-ion recombination of Fe XVII for high temperature plasmas

International Nuclear Information System (INIS)

Nahar, Sultana N.

2012-01-01

Earlier studies on electron-ion recombination of Fe XVII, e+FeXVIII→FeXVII, concentrated on low temperature region. However, due to its higher abundance, recombination in the high temperature region is of great importance. Total and level-specific recombination cross sections and rates of Fe XVII are presented from the detailed study in the high temperature. The calculations were carried out using the unified method which incorporates both the radiative recombination (RR) and dielectronic recombination (DR) including the interference effects. The method also yields self-consistent set of recombination rates and photoionization cross sections. Unified method is implemented through relativistic Breit-Pauli R-matrix (BPRM) method and close coupling (CC) approximation. For the details of the high energy and high temperature features a CC wave function expansion consisting of 60 levels from n=2 and 3 complexes of the core Fe XVIII was considered. Earlier study included core excitations to n=2 levels only. It is found that the resonances due to core excitations to n=3 levels are much more extensive and stronger than those to n=2 levels and increase the recombination considerably in the high temperature region. While earlier study of 3-level calculations agree very well with the experimentally derived low temperature recombination, the high temperature rate shows a broad peak at about 5×10 6 K, near the maximum abundance of the ion, due to dominance of DR via PEC (photo-excitation-of-core) resonances of n=3 levels. Level-specific recombination rate coefficients, which include both the RR and DR, are presented for 454 levels (n≤10, l≤9, 0 ≤J≤8 with even and odd parities) of Fe XVII. This is the first large-scale BPRM calculations for recombination of a complex atomic system beyond He- and Li-like ions. The results are expected to be accurate with 10-20% uncertainty and provide accurate modelings of ultraviolet to X-ray spectra.

Formation of two ripple modes on Si by ion erosion with simultaneous Fe incorporation

International Nuclear Information System (INIS)

Cornejo, Marina; Ziberi, Bashkim; Meinecke, Christoph; Frost, Frank

2011-01-01

This report focuses on the self organized nanostructure formation on Si (0 0 1) by erosion with low energy Kr + ions with simultaneous incorporation of metallic atoms, in particular Fe. The incorporation of Fe is thought to play an important role in the formation of some features. In the experimental set-up used here the Fe atoms come from the sputtering of a cylindrical stainless steel target situated between the source and the sample holder. It is demonstrated how the Fe flux can be regulated by operational parameters of the ion source. It is shown that two different ripple modes, one perpendicular to the ion beam projection on the surface and the other parallel, were formed at near normal incidence (α = 20 o ) with ion energy between 300 eV and 2000 eV and a fluence of 6.7 x 10 18 cm -2 . The perpendicular mode ripples dominated the topography when E ion = 2000 eV, while the parallel mode ripples were the main features observed when E ion = 300 eV. The correlation of Fe concentration with ion sources parameters and resulting topography is analyzed. It is demonstrated that a certain Fe concentration is necessary for the formation of ripples that are oriented perpendicular to the ion beam and that the Fe concentration alone does not determine the evolving topography.

Facile fabrication of composited Mn_3O_4/Fe_3O_4 nanoflowers with high electrochemical performance as anode material for lithium ion batteries

International Nuclear Information System (INIS)

Zhao, Dianyun; Hao, Qin; Xu, Caixia

2015-01-01

Graphical abstract: Mn_3O_4/Fe_3O_4 nanoflowers are successfully prepared through one step dealloying of Mn_5Fe_5Al_9_0 alloy at room temperature. This hierarchical flower-like structure with consists of a packed array of uniform regular hexagon-like nanoslices. Combined with the specific hierarchical flower-like architecture and the synergistic effect exerted by Mn_3O_4 and Fe_3O_4, the nanocomposite exhibits enhanced performance as anode material for lithium ion batteries than pure Mn_3O_4 and Fe_3O_4 anode. - Highlights: • Mn_3O_4/Fe_3O_4 nanoflowers are easily prepared by one step dealloying method. • The nanoflowers consist of packed regular nanoslices with interconnected voids. • Mn_3O_4/Fe_3O_4 nanoflowers deliver higher discharge capacity than Mn_3O_4 and Fe_3O_4. • Mn_3O_4/Fe_3O_4 nanoflowers show lower initial irreversible loss than Mn_3O_4 anode. - Abstract: Mn_3O_4/Fe_3O_4 nanoflowers with controllable components are simply fabricated through one step etching of the Mn_5Fe_5Al_9_0 ternary alloy. The as-made hierarchical flower-like structure with interconnected voids consists of a packed array of uniform regular hexagon-like nanoslices. Based on the simple dealloying strategy the target metals are directly converted to uniform nanocomposite composed of Mn_3O_4 and Fe_3O_4 species. With the unique hierarchical flower-like structure and the synergistic effects between Mn_3O_4 and Fe_3O_4, the nanocomposite exhibits higher performance as anode material for lithium ion batteries than that of pure Mn_3O_4 and Fe_3O_4 anodes. The Mn_3O_4/Fe_3O_4 nanocomposite deliver much higher discharge capacity and lower initial irreversible loss than Mn_3O_4 anode. The Mn_3O_4/Fe_3O_4 anode material also shows an excellent cycling stability at the high rate of 1500 mA g"−"1 with outstanding rate capability. With the advantages of simple preparation and excellent electrochemical performance, Mn_3O_4/Fe_3O_4 nanoflowers manifest great application potential as

Observation of the domain structure in Fe-Au superlattices with perpendicular anisotropy

Energy Technology Data Exchange (ETDEWEB)

Zoladz, M. E-mail: zoladz@uci.agh.edu.pl; Slezak, T.; Wilgocka-Slezak, D.; Spiridis, N.; Korecki, J.; Stobiecki, T. E-mail: stobieck@uci.agh.edu.pl; Roell, K

2004-05-01

Polar Kerr Microscopy was used to visualize characteristic transitions and external magnetic field driven domain structure evolution in a perpendicularly magnetized Fe-Au AF/FM double multilayer structure. Real time imaging performed in the external magnetic field allowed for identification of all sublayers magnetization reversal in accordance with measured PMOKE magnetization curve, showing strong dependence of transition character on the interlayer coupling type and adjacent sublayers magnetization orientation.

Observation of the domain structure in Fe-Au superlattices with perpendicular anisotropy

International Nuclear Information System (INIS)

Zoladz, M.; Slezak, T.; Wilgocka-Slezak, D.; Spiridis, N.; Korecki, J.; Stobiecki, T.; Roell, K.

2004-01-01

Polar Kerr Microscopy was used to visualize characteristic transitions and external magnetic field driven domain structure evolution in a perpendicularly magnetized Fe-Au AF/FM double multilayer structure. Real time imaging performed in the external magnetic field allowed for identification of all sublayers magnetization reversal in accordance with measured PMOKE magnetization curve, showing strong dependence of transition character on the interlayer coupling type and adjacent sublayers magnetization orientation

Physicochemical characterization of Fe3O4/SiO2/Au multilayer nanostructure

International Nuclear Information System (INIS)

Khosroshahi, Mohammad E.; Ghazanfari, Lida

2012-01-01

Highlights: ► The purpose of the research was to synthesize and characterize Fe 3 O 4 /SiO 2 /Au NPs. ► Uncoated MNPs showed an Ms range of 80–100 emu g −1 for particles between 35–96 nm. ► The magnetic NPs were modified with a thin layer of silica using Stober method. ► Small gold colloids (1–3 nm) were covered the amino functionalized particle surface. ► An absorption peak of 550 nm was obtained for a gold thickness of about 35 nm. - Abstract: The purpose of this research was to synthesize and characterize gold-coated Fe 3 O 4 /SiO 2 nanoshells for biomedical applications. Magnetite nanoparticles (NPs) were prepared using co-precipitation method. Smaller particles were synthesized by decreasing the NaOH concentration, which in our case this corresponded to 35 nm using 0.9 M of NaOH at 750 rpm with a specific surface area of 41 m 2 g −1 . For uncoated Fe 3 O 4 NPs, the results showed an octahedral geometry with saturation magnetization range of 80–100 emu g −1 and coercivity of 80–120 Oe for particles between 35 and 96 nm, respectively. The magnetic NPs were modified with a thin layer of silica using Stober method. Small gold colloids (1–3 nm) were synthesized using Duff method and covered the amino functionalized particle surface. Magnetic and optical properties of gold nanoshells were assessed using Brunauer–Emmett–Teller (BET), vibrating sample magnetometer (VSM), UV–Vis spectrophotometer, atomic and magnetic force microscope (AFM, MFM), and transmission electron microscope (TEM). Based on the X-ray diffraction (XRD) results, three main peaks of Au (1 1 1), (2 0 0) and (2 2 0) were identified. The formation of each layer of a nanoshell is also demonstrated by Fourier transform infrared (FTIR) results. The Fe 3 O 4 /SiO 2 /Au nanostructures, with 85 nm as particle size, exhibited an absorption peak at ∼550 nm with a magnetization value of 1.3 emu g −1 with a specific surface area of 71 m 2 g −1 .

Population trapping: The mechanism for the lost resonance lines in Pm-like ions

Science.gov (United States)

Kato, Daiji; Sakaue, Hiroyuki A.; Murakami, Izumi; Nakamura, Nobuyuki

2017-10-01

We report a population kinetics study on line emissions of the Pm-like Bi22+ performed by using a collisional-radiative (CR) model. Population rates of excited levels are analyzed to explain the population trapping in the 4f135s2 state which causes the loss of the 5s - 5p resonance lines in emission spectra. Based on the present analysis, we elucidate why the population trapping is not facilitated for a meta-stable excited level of the Sm-like Bi21+. The emission line spectra are calculated for the Pm-like isoelectronic sequence from Au18+ through W13+ and compared with experimental measurements by electron-beam-ion-traps (EBITs). Structures of the spectra are similar for all of the cases except for calculated W13+ spectra. The calculated spectra are hardly reconciled with the measured W13+ spectrum using the compact electron-beam-ion-trap (CoBIT) [Phys. Rev. A 92 (2015) 022510].

In Situ Studies of Fe4+ Stability in β-Li3Fe2(PO4)3 Cathodes for Li Ion Batteries

DEFF Research Database (Denmark)

Christiansen, Ane Sælland; Johnsen, Rune E.; Norby, Poul

2015-01-01

In commercial Fe-based batteries the Fe2+/Fe3+ oxidation states are used, however by also utilizing the Fe4+ oxidation state, intercalation of up to two Li ions per Fe ion could be possible. In this study, we investigate whether Fe4+ can be formed and stabilized in β-Li3Fe2(PO4)3. The work includes...... of Fe4+ formation. Oxidation of the organic electrolyte is inevitable at 4.5 V but this alone cannot explain the volume change. Instead, a reversible oxygen redox process (O2− → O−) could possibly explain and charge compensate for the reversible extraction of lithium ions from β-Li3Fe2(PO4)3....... in situ synchrotron X-ray powder diffraction studies (XRPD) during charging of β-Li3Fe2(PO4)3 up to 5.0 V vs. Li/Li+. A novel capillary-based micro battery cell for in situ XRPD has been designed for this. During charge, a plateau at 4.5 V was found and a small contraction in volume was observed...

One-pot solvothermal synthesis of graphene wrapped rice-like ferrous carbonate nanoparticles as anode materials for high energy lithium-ion batteries

Science.gov (United States)

Zhang, Fan; Zhang, Ruihan; Feng, Jinkui; Ci, Lijie; Xiong, Shenglin; Yang, Jian; Qian, Yitai; Li, Lifei

2014-11-01

Well dispersed rice-like FeCO3 nanoparticles were produced and combined with reduced graphene oxide (RGO) via a one-pot solvothermal route. SEM characterization shows that rice-like FeCO3 nanoparticles are homogeneously anchored on the surface of the graphene nanosheets; the addition of RGO is helpful to form a uniform morphology and reduce the particle size of FeCO3 to nano-grade. As anode materials for lithium-ion batteries, the FeCO3/RGO nanocomposites exhibit significantly improved lithium storage properties with a large reversible capacity of 1345 mA h g-1 for the first cycle and a capacity retention of 1224 mA h g-1 after 50 cycles with a good rate capability compared with pure FeCO3 particles. The superior electrochemical performance of the FeCO3/RGO nanocomposite electrode compared to the pure FeCO3 electrode can be attributed to the well dispersed RGO which enhances the electronic conductivity and accommodates the volume change during the conversion reactions. Our study shows that the FeCO3/RGO nanocomposite could be a suitable candidate for high capacity lithium-ion batteries.

Sites of Au atoms in Sn crystals as determined by channeling

International Nuclear Information System (INIS)

Miller, J.W.; Gemmell, D.S.; Holland, R.E.; Poizat, J.C.; Worthington, J.N.; Loess, R.E.

1974-01-01

The position of Au atoms diffused into Sn monocrystals has been studied by channeling and backscattering of 2.5-MeV Ne ions. For equilibrium conditions at 217 0 C, Au atoms are found almost entirely in substitutional positions, so that the unusually fast diffusion of Au in Sn most likely arises from a small fraction of Au atoms migrating interstitially

Environmental application of millimetre-scale sponge iron (s-Fe"0) particles (IV): New insights into visible light photo-Fenton-like process with optimum dosage of H_2O_2 and RhB photosensitizers

International Nuclear Information System (INIS)

Ju, Yongming; Yu, Yunjiang; Wang, Xiaoyan; Xiang, Mingdeng; Li, Liangzhong; Deng, Dongyang; Dionysiou, Dionysios D.

2017-01-01

Highlights: • Synergistic action of Rhodamine B (RhB), visible light, H_2O_2 and s-Fe"0 is essential. • The complexes of RhB and Fe"3"+ eject one electron via ligand-to-metal charge-transfer. • RhB assists the photo-Fenton-like removal of tetrabromobisphenol A (TBBPA). - Abstract: In this study, we firstly develop the photo-Fenton-like system with millimetric sponge iron (s-Fe"0), H_2O_2, visible light (vis, λ ≥ 420 nm) and rhodamine B (RhB), and present a comprehensive study concerning the mechanism. Thus, we investigate (1) the adsorption of RhB onto s-Fe"0, (2) the photo-Fenton-like removal of RhB over iron oxides generated from the corrosion of s-Fe"0, (3) the homogeneous photo-Fenton removal of RhB over Fe"2"+ or Fe"3"+, (4) the Fe"3"+-RhB complexes, and (5) the photo-Fenton-like removal of tetrabromobisphenol A (TBBPA). The results show that neither the adsorption process over s-Fe"0 nor the photo-Fenton-like process over FeOOH, Fe_3O_4 and Fe_2O_3, achieved efficient removal of RhB. For comparison, in homogeneous photo-Fenton process, the presence of Fe"3"+ ions, rather than Fe"2"+ ions, effectively eliminated RhB. Furthermore, the UV–vis spectra showing new absorbance at ∼ 285 nm indicate the complexes of RhB and Fe"3"+ ions, adopting vis photons to form excited state and further eject one electron via ligand-to-metal charge-transfer to activate H_2O_2. Additionally, efficient TBBPA removal was obtained only in the presence of RhB. Accordingly, the s-Fe"0– based photo-Fenton-like process assisted with dyestuff wastewater is promising for removing a series of persistent organic pollutants.

Synthesis of dumbbell-like Au nanostructure and its light-absorbance study

International Nuclear Information System (INIS)

Shen Jianlei; Xu Yan; Li Kun; Song Shiping; Fan Chunhai

2013-01-01

Background: By changing the size or the morphology of Au nanostructure, they can absorb different wavelength light due to the localized surface plasmon resonance (LSPR). Because Au nanorods show good ability to transform light into heat (photothermal effect), they have been wildly used to deliver the drugs and release them controllably. However, when applying such nanostructure for in vivo treatments, Au nanorods must have long aspect ratio which often make it hard to prepare heterogeneous nanostructure. Purpose: A new method to synthesize Au nanostructure with uniform size and to achieve long wavelength light absorbance is needed. This work attempts to synthesize such Au nanostructure by using bio-nano techniques. Methods: New nanostructures are prepared by growing Au nanoparticles on the surface of Au nanorods modified with DNA molecules. Results: Dumbbell-Ikea Au nanostructures were prepared firstly. Its maximum absorbance locates at near ultraviolet region, which means that it can be used as a potential tool for the deep-skin photothermal treatment. Moreover, other two kinds of nanostructures, i.e. Au nanorods with Au splinter at two ends and sea urchin-like nanostructures, are also studied. Conclusions: We successfully fabricated novel Au nanostructures which can be used for drug delivery, surface-enhanced Raman spectroscopy and catalysis. (authors)

CO adsorption on small Au{sub n} (n = 1–4) structures supported on hematite. I. Adsorption on iron terminated α-Fe{sub 2}O{sub 3} (0001) surface

Energy Technology Data Exchange (ETDEWEB)

Pabisiak, Tomasz; Kiejna, Adam, E-mail: kiejna@ifd.uni.wroc.pl [Institute of Experimental Physics, University of Wrocław, Plac M. Borna 9, 50-204 Wrocław (Poland); Winiarski, Maciej J. [Institute of Experimental Physics, University of Wrocław, Plac M. Borna 9, 50-204 Wrocław (Poland); Institute of Low Temperature and Structure Research, Polish Academy of Sciences, ul. Okólna 2, 50-422 Wrocław (Poland)

2016-01-28

This is the first of two papers dealing with the adsorption of Au and formation of Au{sub n} nanostructures (n = 1–4) on hematite (0001) surface and adsorption of CO thereon. The stoichiometric Fe-terminated (0001) surface of hematite was investigated using density functional theory in the generalized gradient approximation of Perdew-Burke-Ernzerhof (PBE) form with Hubbard correction U, accounting for strong electron correlations (PBE+U). The structural, energetic, and electronic properties of the systems studied were examined for vertical and flattened configurations of Au{sub n} nanostructures adsorbed on the hematite surfaces. The flattened ones, which can be viewed as bilayer-like structures, were found energetically more favored than vertical ones. For both classes of structures the adsorption binding energy increases with the number of Au atoms in a structure. The adsorption of Au{sub n} induces charge rearrangement at the Au{sub n}/oxide contact which is reflected in work function changes. In most considered cases Au{sub n} adsorption increases the work function. A detailed analysis of the bonding electron charge is presented and the corresponding electron charge rearrangements at the contacts were quantified by a Bader charge analyses. The interaction of a CO molecule with the Au{sub n} nanostructures supported on α-Fe{sub 2}O{sub 3} (0001) and the oxide support was studied. It is found that the CO adsorption binding to the hematite supported Au{sub n} structures is more than twice as strong as to the bare hematite surface. Analysis of the Bader charges on the atoms showed that in each case CO binds to the most positively charged (cationic) atom of the Au{sub n} structure. Changes in the electronic structure of the Au{sub n} species and of the oxide support, and their consequences for the interactions with CO, are discussed.

Neurogenic Effects of Low-Dose Whole-Body HZE (Fe) Ion and Gamma Irradiation.

Science.gov (United States)

Sweet, Tara B; Hurley, Sean D; Wu, Michael D; Olschowka, John A; Williams, Jacqueline P; O'Banion, M Kerry

2016-12-01

Understanding the dose-toxicity profile of radiation is critical when evaluating potential health risks associated with natural and man-made sources in our environment. The purpose of this study was to evaluate the effects of low-dose whole-body high-energy charged (HZE) iron (Fe) ions and low-energy gamma exposure on proliferation and differentiation of adult-born neurons within the dentate gyrus of the hippocampus, cells deemed to play a critical role in memory regulation. To determine the dose-response characteristics of the brain to whole-body Fe-ion vs. gamma-radiation exposure, C57BL/6J mice were irradiated with 1 GeV/n Fe ions or a static 137 Cs source (0.662 MeV) at doses ranging from 0 to 300 cGy. The neurogenesis was analyzed at 48 h and one month postirradiation. These experiments revealed that whole-body exposure to either Fe ions or gamma radiation leads to: 1. An acute decrease in cell division within the dentate gyrus of the hippocampus, detected at doses as low as 30 and 100 cGy for Fe ions and gamma radiation, respectively; and 2. A reduction in newly differentiated neurons (DCX immunoreactivity) at one month postirradiation, with significant decreases detected at doses as low as 100 cGy for both Fe ions and gamma rays. The data presented here contribute to our understanding of brain responses to whole-body Fe ions and gamma rays and may help inform health-risk evaluations related to systemic exposure during a medical or radiologic/nuclear event or as a result of prolonged space travel.

Anomalous Hall effect in Fe/Au multilayers

KAUST Repository

Zhang, Q.; Li, P.; Wen, Yan; Zhao, C.; Zhang, Junwei; Manchon, Aurelien; Mi, W. B.; Peng, Y.; Zhang, Xixiang

2016-01-01

To understand the interfacial scattering effect on the anomalous Hall effect (AHE), we prepared multilayers of (Fe(36/n)nm/Au(12/n)nm)n using an e-beam evaporator. This structure design allowed us to investigate the effect of interfacial scattering on the AHE, while keeping the samples' thickness and composition unchanged. We measured the (magneto)transport properties of the samples in a wide temperature range (10–310 K) with magnetic fields up to 50 kOe. We found that the scaling between the anomalous Hall resistivity (ρAHE) and longitudinal resistivity (ρxx) can be roughly described by ρAHE∼ργxx with γ=2.65±0.10 and 1.90 ± 0.04 for samples from n=1 to n=4 and samples from n=4 to n=12, respectively. Our quantitative analysis results showed that the interfacial scattering suppresses the contribution of the intrinsic mechanism and gives rise to a side-jump contribution.

Anomalous Hall effect in Fe/Au multilayers

KAUST Repository

Zhang, Q.

2016-07-22

To understand the interfacial scattering effect on the anomalous Hall effect (AHE), we prepared multilayers of (Fe(36/n)nm/Au(12/n)nm)n using an e-beam evaporator. This structure design allowed us to investigate the effect of interfacial scattering on the AHE, while keeping the samples\\' thickness and composition unchanged. We measured the (magneto)transport properties of the samples in a wide temperature range (10–310 K) with magnetic fields up to 50 kOe. We found that the scaling between the anomalous Hall resistivity (ρAHE) and longitudinal resistivity (ρxx) can be roughly described by ρAHE∼ργxx with γ=2.65±0.10 and 1.90 ± 0.04 for samples from n=1 to n=4 and samples from n=4 to n=12, respectively. Our quantitative analysis results showed that the interfacial scattering suppresses the contribution of the intrinsic mechanism and gives rise to a side-jump contribution.

Improvement of the magnetic moment of NiZn ferrites induced by substitution of Nd3+ ions for Fe3+ ions

Science.gov (United States)

Wu, Xuehang; Chen, Wen; Wu, Wenwei; Wu, Juan; Wang, Qing

2018-05-01

Four types of Ni-Zn based ferrites materials having the general formula Ni0.5Zn0.5NdxFe2-xO4 (0.0 ≤ x ≤ 0.12) have been successfully synthesized by calcining oxalates in air and the influence of Nd content on the structure and magnetic properties of Ni0.5Zn0.5NdxFe2-xO4 is studied. X-ray diffraction examination confirms that a high-crystallized Ni0.5Zn0.5NdxFe2-xO4 with cubic spinel structure is obtained when the precursor is calcined at 1000 °C in air for 2 h. The substitutions of Nd3+ ions for partial Fe3+ ions do not change the spinel crystalline structure of MFe2O4. The incorporation of Nd3+ ions in place of Fe3+ ions in Ni-Zn ferrites increases the average crystallite size. Specific saturation magnetization decreases with increase in Nd content. This is because Nd3+ ions with smaller magnetic moment preferentially fill the octahedral sites. In addition, antiferromagnetic FeNdO3 increases with increase in Nd content. In this study, Ni0.5Zn0.5Nd0.08Fe1.92O4, calcined at 1000 °C, exhibits the highest magnetic moment (4.2954 μB) and the lowest coercivity (28.82 Oe).

MULTI-SPACECRAFT ANALYSIS OF ENERGETIC HEAVY ION AND INTERPLANETARY SHOCK PROPERTIES IN ENERGETIC STORM PARTICLE EVENTS NEAR 1 au

Energy Technology Data Exchange (ETDEWEB)

Ebert, R. W.; Dayeh, M. A.; Desai, M. I. [Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238 (United States); Jian, L. K. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Li, G. [The Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35756 (United States); Mason, G. M., E-mail: rebert@swri.edu [Johns Hopkins University/Applied Physics Laboratory, Laurel, MD 20273 (United States)

2016-11-10

We examine the longitude distribution of and relationship between interplanetary (IP) shock properties and ∼0.1–20 MeV nucleon{sup -1} O and Fe ions during seven multi-spacecraft energetic storm particle (ESP) events at 1 au. These ESP events were observed at two spacecraft and were primarily associated with low Mach number, quasi-perpendicular shocks. Key observations include the following: (i) the Alfvén Mach number increased from east to west of the coronal mass ejection source longitude, while the shock speed, compression ratios, and obliquity showed no clear dependence; (ii) the O and Fe time intensity profiles and peak intensities varied significantly between longitudinally separated spacecraft observing the same event, the peak intensities being larger near the nose and smaller along the flank of the IP shock; (iii) the O and Fe peak intensities had weak to no correlations with the shock parameters; (iv) the Fe/O time profiles showed intra-event variations upstream of the shock that disappeared downstream of the shock, where values plateaued to those comparable to the mean Fe/O of solar cycle 23; (v) the O and Fe spectral index ranged from ∼1.0 to 3.4, the Fe spectra being softer in most events; and (vi) the observed spectral index was softer than the value predicted from the shock compression ratio in most events. We conclude that while the variations in IP shock properties may account for some variations in O and Fe properties within these multi-spacecraft events, detailed examination of the upstream seed population and IP turbulence, along with modeling, are required to fully characterize these observations.

Irradiation effects in Fe-30%Ni alloy during Ar ion implantation

International Nuclear Information System (INIS)

Soukieh, Mohamad; Al-Mohamad, Ali

1993-12-01

The use of metallic thin films for studying the processes which take place during ion irradiation has recently increased. For example, ion implantation is widely used to study the structural defects in transition metallic thin films such as (Fe, Ni, Co), because it can simulate the effects occurring in nuclear reactors during neutron irradiation especially the swelling of reactor materials. The swelling of metals and alloys is strongly related to the material structure and to the irradiation conditions. The general feature of formation of structural defects as a function of irradiation dosage and annealing temperature is well known. However, the detailed mechanisms are still not well understood. For example, the swelling of iron alloy with 30-35% nickel is very small in comparison with other Ni concentrations, and there is no clear information on the possibility of phase transitions in fe-Ni alloys during irradiation. The aim of this work is to study the phase-structural changes in Fe-30% Ni implanted by high dose of argon ions. The effect of irradiation with low energy argon ions (40 KeV, and fluences of 10.E15 to 10.E17 ions/cm) on the deposited thin films of Fe-30% Ni alloy was investigated using RBS and TEM techniques. The thicknesses of these films were about 65+-10 nm deposited on ceramic, KBr, and Be fiols substrates. Gas bubble formation and profile distribution of the implanted argon ions were investigated. Formation of an ordered phase Fe 3 Ni during irradiation appears to inhibit gas bubble formations in the film structure. (author). 17 refs., 15 figs., 7 tabs

Moessbauer study of FePO4 cathode for lithium- and sodium-ion batteries

International Nuclear Information System (INIS)

Tetsuaki Nishida; Masahiro Tokunaga; Toshiharu Nishizumi; Takafumi Yamamoto; Tomoyuki Shiratsuchi; Shigeto Okada; Jun-ichi Yamaki

2005-01-01

LiFePO 4 of olivine type has attracted much interest as a rare-metal free cathode for lithium-ion battery. The present authors' group has found a low-cost preparation method for new cathode material FePO 4 (P 321 ) from an aqueous solution of metallic iron and P 2 O 5 . A cathode pellet was prepared by mixing FePO 4 , acetylene black (AB) and polytetrafluoroethylene (PTFE) binder at a mass ratio of 70:25:5. Electrochemical cathode performance was investigated under a constant current density of 0.1 mA/cm 2 with a coin-type cell with an anode of metallic Li and Na for Li- and Na-ion batteries, respectively. Moessbauer spectra were measured by a constant accele- ration method with a Moessbauer source of 57 Co(Pd) and an α-Fe foil as a reference of the isomer shift. Moessbauer spectra of the original cathode pellet top left and right) composed of amorphous FePO 4 indicate that all the Fe III atoms have a tetrahedral symmetry. After discharging the Li-(second left) and Na-batteries (second right), all the Fe III were reduced to octahedral Fe II . The reduction of Fe III to Fe II indicates penetration of Li + and Na + into the FePO 4 cathode which accompanies an electron capture; Li + (or Na + ) + Fe III PO 4 + e - = LiFe II PO 4 (or NaFe II PO 4 ) After charging the Li-cell (bottom left), all the Fen atoms were oxidized to tetrahedral Fe III , while 69 % of Fe II was oxidized to Fe III in the Na-ion cell (bottom right) due to a lower cell voltage: 4.0 V. Oxidation of Fe II to Fe III reflects a release of Li + or Na + ions from the FePO 4 cathode to the electrolyte, i.e., an inverse reaction of eq.

The synthesis and characterization of polymer-coated FeAu multifunctional nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Liu Hongling; Hou Peng; Zhang Wengxing [Institute of Molecular and Crystal Engineering, School of Chemistry and Chemical Engineering, Henan University, Kaifeng 475001, Henan (China); Kim, Young Keun [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Wu Junhua, E-mail: feitianshenhu@yahoo.com [Research Institute of Engineering and Technology, Korea University, Seoul 136-713 (Korea, Republic of)

2010-08-20

We report the one-pot nanoemulsion synthesis of FeAu magnetic-optical multifunctional nanoparticles coated by the biocompatible triblock copolymer, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO). The FTIR study confirms the PEO-PPO-PEO molecules on the surface of the resulting nanoparticles. The structural characterization identifies the crystallographic parameter 4.072 A of the cubic phase and the morphology analysis gives the nanoparticle shape, size and size distribution, showing the high crystallinity of the FeAu nanoparticles and an average particle size of {approx} 6.5 nm. In addition there is direct confirmation of the alloying by elemental point probing of an individual nanoparticle. Following the visual demonstration of a rapid, efficient and reversible dispersion-collection process of the nanoparticles in solution, the magnetic measurement manifests a soft ferromagnetic behavior of the nanoparticles with a small coercivity of {approx} 60 Oe at room temperature. The corresponding magnetic hysteresis curves were effectively assessed by modified bi-phase Langevin equations, which were satisfactorily explained in terms of a bimodal particle size distribution. The UV-vis studies display the broadband absorption of the PEO-PPO-PEO-coated nanoparticles with the maximum surface plasmon resonance around 585 nm. The characterization and analysis, therefore, shows the unification of iron and gold into one alloy nanostructure entity covered by the biocompatible triblock copolymer thin film, preserving the optical and magnetic properties of the individual constituents. This gives the prospect of enhanced performance in applications.

The synthesis and characterization of polymer-coated FeAu multifunctional nanoparticles

International Nuclear Information System (INIS)

Liu Hongling; Hou Peng; Zhang Wengxing; Kim, Young Keun; Wu Junhua

2010-01-01

We report the one-pot nanoemulsion synthesis of FeAu magnetic-optical multifunctional nanoparticles coated by the biocompatible triblock copolymer, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO). The FTIR study confirms the PEO-PPO-PEO molecules on the surface of the resulting nanoparticles. The structural characterization identifies the crystallographic parameter 4.072 A of the cubic phase and the morphology analysis gives the nanoparticle shape, size and size distribution, showing the high crystallinity of the FeAu nanoparticles and an average particle size of ∼ 6.5 nm. In addition there is direct confirmation of the alloying by elemental point probing of an individual nanoparticle. Following the visual demonstration of a rapid, efficient and reversible dispersion-collection process of the nanoparticles in solution, the magnetic measurement manifests a soft ferromagnetic behavior of the nanoparticles with a small coercivity of ∼ 60 Oe at room temperature. The corresponding magnetic hysteresis curves were effectively assessed by modified bi-phase Langevin equations, which were satisfactorily explained in terms of a bimodal particle size distribution. The UV-vis studies display the broadband absorption of the PEO-PPO-PEO-coated nanoparticles with the maximum surface plasmon resonance around 585 nm. The characterization and analysis, therefore, shows the unification of iron and gold into one alloy nanostructure entity covered by the biocompatible triblock copolymer thin film, preserving the optical and magnetic properties of the individual constituents. This gives the prospect of enhanced performance in applications.

Iron loading effects in Fe/SSZ-13 NH3-SCR catalysts: nature of the Fe-ions and structure-function relationships

Energy Technology Data Exchange (ETDEWEB)

Gao, Feng; Zheng, Yang; Kukkadapu, Ravi K.; Wang, Yilin; Walter, Eric D.; Schwenzer, Birgit; Szanyi, Janos; Peden, Charles HF

2016-05-06

Using a traditional aqueous solution ion-exchange method under a protecting atmosphere of N2, a series of Fe/SSZ-13 catalysts with various Fe loadings were synthesized. UV-Vis, EPR and Mössbauer spectroscopies, coupled with temperature programmed reduction and desorption techniques, were used to probe the nature of the Fe sites. The major monomeric and dimeric Fe species are extra-framework [Fe(OH)2]+ and [HO-Fe-O-Fe-OH]2+. Larger oligomers with unknown nuclearity, poorly crystallized Fe2O3 particles, together with isolated Fe2+ ions, are minor Fe-containing moieties. Reaction rate and Fe loading correlations suggest that isolated Fe3+ ions are the active sites for standard SCR while the dimeric sites are the active centers for NO oxidation. NH3 oxidation, on the other hand, is catalyzed by sites with higher nuclearity. A low-temperature standard SCR reaction network is proposed that includes redox cycling of both monomeric and dimeric Fe species, for SCR and NO2 generation, respectively. The authors gratefully acknowledge the US Department of Energy (DOE), Energy Efficiency and Renewable Energy, Vehicle Technologies Program for the support of this work. The research described in this paper was performed at the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated for the US DOE by Battelle.

Tandem accelerator transmission and life measurement of 50 keV/amu Au ions using stripper foil made by INS

Energy Technology Data Exchange (ETDEWEB)

Ishii, Satoshi; Takahashi, Tsutomu; Shima, Kunihiro [Tsukuba Univ., Ibaraki (Japan). Tandem Accelerator Center; Sugai, Isamu; Oyaizu, Mitsuhiro

1996-12-01

The role of stripper foil is the charge exchange of ions. The thickness for attaining equilibrium in charge exchange becomes thinner as ions become lower speed and heavier. Accordingly, for the stripper foil, thin foil thickness is demanded in addition to the demand of long life. The stripper foil made by INS, University of Tokyo, is recognized as its long life. In the 12 UD PELETRON tandem accelerator in University of Tsukuba, in order to meet the demand of users to use heavy ions, the use of long life stripper foil has become urgent necessity. Therefore, as for the foil made by INS, the life by Au ion irradiation and the Au ion transmission were measured four times. As to the features of the test of this time, irradiation was carried out under the severe condition for the foil of low speed Au ions, and the change of beam transmission with time lapse was observed in addition to the life. The method of measurement is explained. The preparation of foils and the determination of their thickness are reported. As the results, the lifetime of the foils made by INS and the thickness dependence and time dependence or dose dependence of the transmission of low speed, heavy Au-197 ions are described. (K.I.)

Discovery of Suprathermal Ionospheric Origin Fe+ in and Near Earth's Magnetosphere

Science.gov (United States)

Christon, S. P.; Hamilton, D. C.; Plane, J. M. C.; Mitchell, D. G.; Grebowsky, J. M.; Spjeldvik, W. N.; Nylund, S. R.

2017-11-01

Suprathermal (87-212 keV/e) singly charged iron, Fe+, has been discovered in and near Earth's 9-30 RE equatorial magnetosphere using 21 years of Geotail STICS (suprathermal ion composition spectrometer) data. Its detection is enhanced during higher geomagnetic and solar activity levels. Fe+, rare compared to dominant suprathermal solar wind and ionospheric origin heavy ions, might derive from one or all three candidate lower-energy sources: (a) ionospheric outflow of Fe+ escaped from ion layers near 100 km altitude, (b) charge exchange of nominal solar wind iron, Fe+≥7, in Earth's exosphere, or (c) inner source pickup Fe+ carried by the solar wind, likely formed by solar wind Fe interaction with near-Sun interplanetary dust particles. Earth's semipermanent ionospheric Fe+ layers derive from tons of interplanetary dust particles entering Earth's atmosphere daily, and Fe+ scattered from these layers is observed up to 1000 km altitude, likely escaping in strong ionospheric outflows. Using 26% of STICS's magnetosphere-dominated data when possible Fe+2 ions are not masked by other ions, we demonstrate that solar wind Fe charge exchange secondaries are not an obvious Fe+ source. Contemporaneous Earth flyby and cruise data from charge-energy-mass spectrometer on the Cassini spacecraft, a functionally identical instrument, show that inner source pickup Fe+ is likely not important at suprathermal energies. Consequently, we suggest that ionospheric Fe+ constitutes at least a significant portion of Earth's suprathermal Fe+, comparable to the situation at Saturn where suprathermal Fe+ is also likely of ionospheric origin.

Amperometric glucose sensor based on enhanced catalytic reduction of oxygen using glucose oxidase adsorbed onto core-shell Fe3O4-silica-Au magnetic nanoparticles

International Nuclear Information System (INIS)

Wang Aijun; Li Yongfang; Li Zhonghua; Feng Jiuju; Sun Yanli; Chen Jianrong

2012-01-01

Monodisperse Fe 3 O 4 magnetic nanoparticles (NPs) were prepared under facile solvothermal conditions and successively functionalized with silica and Au to form core/shell Fe 3 O 4 -silica-Au NPs. Furthermore, the samples were used as matrix to construct a glucose sensor based on glucose oxidase (GOD). The immobilized GOD retained its bioactivity with high protein load of 3.92 × 10 −9 mol·cm −2 , and exhibited a surface-controlled quasi-reversible redox reaction, with a fast heterogeneous electron transfer rate of 7.98 ± 0.6 s −1 . The glucose biosensor showed a broad linear range up to 3.97 mM with high sensitivity of 62.45 μA·mM −1 cm −2 and fast response (less than 5 s). - Graphical abstract: Core-shell structured Fe 3 O 4 -silica-Au nanoparticles were prepared and used as matrix to construct an amperometric glucose sensor based on glucose oxidase, which showed broad linear range, high sensitivity, and fast response. Highlights: ► Synthesis of monodispersed Fe 3 O 4 nanoparticles. ► Fabrication of core/shell Fe 3 O 4 -silica-Au nanoparticles. ► Construction of a novel glucose sensor with wide linear range, high sensitivity and fast response.

Au functionalized ZnO rose-like hierarchical structures and their enhanced NO2 sensing performance

Science.gov (United States)

Shingange, K.; Swart, H. C.; Mhlongo, G. H.

2018-04-01

Herein, we present ZnO rose-like hierarchical nanostructures employed as support to Au nanoparticles to produce Au functionalized three dimensional (3D) ZnO hierarchical nanostructures (Au/ZnO) for NO2 detection using a microwave-assisted method. Comparative analysis of NO2 sensing performance between the pristine ZnO and Au/ZnO rose-like structures at 300 °C revealed improved NO2 response and rapid response-recovery times with Au incorporation owing to a combination of high surface accessibility induced by hierarchical nanostructure design and catalytic activity of the small Au nanoparticles. Structural and optical analyses acquired from X-ray diffraction, scanning electron microscopy, transmission electron microscope and photoluminescence spectroscopy were also performed.

Investigation of reordered (001) Au surfaces by positive ion channeling spectroscopy, LEED and AES

International Nuclear Information System (INIS)

Appleton, B.R.; Noggle, T.S.; Miller, J.W.; Schow, O.E. III; Zehner, D.M.; Jenkins, L.H.; Barrett, J.H.

1974-01-01

As a consequence of the channeling phenomenon of positive ions in single crystals, the yield of ions Rutherford scattered from an oriented single crystal surface is dependent on the density of surface atoms exposed to the incident ion beam. Thus, the positive ion channeling spectroscopy (PICS) technique should provide a useful tool for studying reordered surfaces. This possibility was explored by examining the surfaces of epitaxially grown thin Au single crystals with the combined techniques of LEED-AES and PICS. The LEED and AES investigations showed that when the (001) surface was sputter cleaned in ultra-high vacuum, the normal (1 x 1) symmetry of the (001) surfaces reordered into a structure which gave a complex (5 x 20) LEED pattern. The yield and energy distributions of 1 MeV He ions scattered from the Au surfaces were used to determine the number of effective monolayers contributing to the normal and reordered surfaces. These combined measurements were used to characterize the nature of the reordered surface. The general applicability of the PICS technique for investigations of surface and near surface regions is discussed

Production of highly charged ion beams from electron cyclotron resonance ion sources (invited)

International Nuclear Information System (INIS)

Xie, Z.Q.

1998-01-01

Electron cyclotron resonance ion source (ECRIS) development has progressed with multiple-frequency plasma heating, higher mirror magnetic fields, and better technique to provide extra cold electrons. Such techniques greatly enhance the production of highly charged ions from ECRISs. So far at continuous wave (CW) mode operation, up to 300 eμA of O 7+ and 1.15 emA of O 6+ , more than 100 eμA of intermediate heavy ions for charge states up to Ar 13+ , Ca 13+ , Fe 13+ , Co 14+ , and Kr 18+ , and tens of eμA of heavy ions with charge states to Kr 26+ , Xe 28+ , Au 35+ , Bi 34+ , and U 34+ were produced from ECRISs. At an intensity of at least 1 eμA, the maximum charge state available for the heavy ions are Xe 36+ , Au 46+ , Bi 47+ , and U 48+ . An order of magnitude enhancement for fully stripped argon ions (I≥60enA) were also achieved. This article will review the ECR ion source progress and discuss key requirement for ECRISs to produce the highly charged ion beams. copyright 1998 American Institute of Physics

Oxide ion diffusion mechanism related to Co and Fe ions in (Ba0.5Sr0.5)(Co0.8Fe0.2)O3-δ using in-situ X-ray absorption spectroscopy

Science.gov (United States)

Itoh, Takanori; Imai, Hideto

2018-03-01

The time changes of the white line and pre-edge intensities of Co and Fe K-edge in (Ba0.5Sr0.5)(Co0.8Fe0.2)O3-δ (BSCF) were observed to estimate the oxide ion diffusion related to Co and Fe ions by using in - situ X-ray absorption spectroscopy (XAS) during oxidation. The 20 μm self-standing BSCF film was prepared for in - situ XAS measurements. The time changes of absorption were fitted to the exponential decay function with two terms. The longer relaxation time (τ), related to the oxide ion diffusion during the oxidation of BSCF, is dependent on temperature. The oxide ion diffusion coefficients (D) were calculated from the τ s estimated by in - situ XAS. The values of the activation energy (Ea) for D related to Co K-edge white line, Co pre-edge, and Fe pre-edge were 1.8-2.0 eV. The value of Ea for D related to Fe K-edge white line, however, was higher than other absorption values at approximately 2.3 eV. We discussed the oxide ion diffusion mechanism related to Co and Fe ions in BSCF using in - situ XAS.

Anti-biofilm activity of Fe heavy ion irradiated polycarbonate

Energy Technology Data Exchange (ETDEWEB)

Joshi, R.P. [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Hareesh, K., E-mail: appi.2907@gmail.com [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Bankar, A. [Department of Microbiology, Waghire College, Pune 412301 (India); Sanjeev, Ganesh [Microtron Centre, Department of Studies in Physics, Mangalore University, Mangalore 574166 (India); Asokan, K.; Kanjilal, D. [Inter University Accelerator Centre, Arun Asaf Ali Marg, New Delhi 110067 (India); Dahiwale, S.S.; Bhoraskar, V.N. [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Dhole, S.D., E-mail: sanjay@physics.unipune.ac.in [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India)

2016-10-01

Highlights: • PC films were irradiated by 60 and 120 MeV Fe ions. • Irradiated PC films showed changes in its physical and chemical properties. • Irradiated PC also showed more anti-biofilm activity compared to pristine PC. - Abstract: Polycarbonate (PC) polymers were investigated before and after high energy heavy ion irradiation for anti-bacterial properties. These PC films were irradiated by Fe heavy ions with two energies, viz, 60 and 120 MeV, at different fluences in the range from 1 × 10{sup 11} ions/cm{sup 2} to 1 × 10{sup 13} ions/cm{sup 2}. UV-Visible spectroscopic results showed optical band gap decreased with increase in ion fluences due to chain scission mainly at carbonyl group of PC which is also corroborated by Fourier transform infrared spectroscopic results. X-ray diffractogram results showed decrease in crystallinity of PC after irradiation which leads to decrease in molecular weight. This is confirmed by rheological studies and also by differential scanning calorimetric results. The irradiated PC samples showed modification in their surfaces prevents biofilm formation of human pathogen, Salmonella typhi.

130 MeV Au ion irradiation induced dewetting on In2Te3 thin film

International Nuclear Information System (INIS)

Matheswaran, P.; Abhirami, K.M.; Gokul, B.; Sathyamoorthy, R.; Prakash, Jai; Asokan, K.; Kanjilal, D.

2012-01-01

Highlights: ► In 2 Te 3 phase formed from In/Te bilayer by 130 MeV Au ion irradiation. ► Lower fluence results mixed phases with initial state of dewetting. ► At higher fluence, In 2 Te 3 phase with complete dewetting pattern is formed. ► Thermal spike model is used to explain the inter face mixing phenomena. ► SHI irradiation may be used to functionalize the structural and surface properties of thin films. - Abstract: In/Te bilayer thin films were prepared by sequential thermal evaporation and subsequently irradiated by 130 MeV Au ions. The pristine and irradiated samples were characterized by X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) techniques. RBS spectra reveal the sputtering of Te film and interface mixing, with increasing fluence. The surface morphology showed the beginning of dewetting of Te thin film and formation of the partially connected with the mixed zones at the fluence of 1 × 10 13 ions/cm 2 . At the higher fluence of 3 × 10 13 ions/cm 2 , dewetted structures were isolated at the surface. Above results are explained based on the formation of craters, sputtering and dewetting followed by inter-diffusion at the interface of molten zones due to thermal spike induced by Au ions.

Ultra-low cost and highly stable hydrated FePO4 anodes for aqueous sodium-ion battery

Science.gov (United States)

Wang, Yuesheng; Feng, Zimin; Laul, Dharminder; Zhu, Wen; Provencher, Manon; Trudeau, Michel L.; Guerfi, Abdelbast; Zaghib, Karim

2018-01-01

The growing demands for large-scale energy storage devices have put a spotlight on aqueous sodium-ion batteries, which possess a number of highly desirable features, such as sodium abundance, low cost and safety over organic electrolytes. While lots of cathode materials were reported, only few candidate materials like active carbon and NaTi2(PO4)3 were proposed as anodes. It is a long-standing common knowledge that the low cost, non-toxicity, and highly reversible FePO4·2H2O is known as an attractive cathode material for non-aqueous lithium- and sodium-ion batteries, but we demonstrate for the first time that nano-size non-carbon coated amorphous FePO4·2H2O can be used as the anode for an aqueous sodium-ion battery. Its optimum operating voltage (∼2.75 V vs. Na+/Na) avoids hydrogen evolution. The capacity is as high as 80 mAh/g at a rate of 0.5 C in a three-electrode system. The full cell, using the Na0.44MnO2 as cathode, maintained 90% of the capacity at 300 cycles at a rate of 3 C. The calculations also show that its volume change during the intercalation of Na ions is below 2%. Its low cost, high safety, along with its outstanding electrochemical performance makes amorphous FePO4·2H2O a promising anode material for aqueous sodium-ion batteries.

Study of the heavy ions (Au+Au at 150 AMeV) collisions with the FOPI detector. Comparison with the Landau-Vlasov model; Etude des collisions d`ions lourds AU+AU a 150 A.MeV avec le detecteur FOPI. Comparaison avec le modele de Landau-Vlasov

Energy Technology Data Exchange (ETDEWEB)

Boussange, S

1995-09-15

In this thesis, heavy ions (Au+Au) collisions experiments are made at 150 AMeV.In the first part, a general study of the nuclear matter equation is presented. Then the used Landau-Vlasov theoretical model is describe. The third part presents the FOPI experience and the details of how to obtain this theoretical predictions (filter, cuts, corrections, possible centrality selections).At the end, experimental results and comparisons with the Landau-Vlasov model are presented. (TEC). 105 refs., 96 figs., 14 tabs.

Uptake of CrO42- ions by Fe-treated tri-calcium phosphate

International Nuclear Information System (INIS)

Serrano G, J.; Ramirez S, J. L.; Bonifacio M, J.; Granados C, F.; Badillo A, V. E.

2010-01-01

CrO 4 2- ion adsorption of Fe-treated tri-calcium phosphate was studied by batch experiments as a function of contact time, initial concentration of metal ion and temperature. Adsorption results showed that at ph 5.5 and 1.0 x 10 -4 M chromium concentration the adsorption capacity of Fe-treated tri-calcium phosphate for CrO 4 2- ions was 7.10 x 10 -3 mmol/g. Chromium adsorption data on Fe-treated tri-calcium phosphate at various initial concentration fitted the Freundlich isotherm. By temperature studies the thermodynamic parameters ΔH 0 , ΔG 0 and ΔS 0 were estimated and the obtained results showed that the adsorption reaction was endothermic and spontaneous. (Author)

Adsorption kinetic parameters of Fe3+ and Ni2+ ions by gyrolite

Directory of Open Access Journals (Sweden)

Kestutis Baltakys

2015-03-01

Full Text Available In this work the adsorption kinetic parameters for Fe3+ and Ni2+ ions by gyrolite are presented. Additionally, the adsoption mechanism was described by using pseudo first order and pseudo second order  equations. It was determined that the adsorption capacity of gyrolite and intrusion of heavy metals ions in its structure depends on reaction time and the pH value of adsorptive. It was observed that the incorporation of Fe3+ ions occurs more intensive than Ni2+ ions. It was found that in the acidic solution the intrusion of Fe3+ ions into gyrolite structure proceeds by two types of chemical reaction mechanisms: substitution and addition. Meanwhile, nickel ions were participated only in substitution reaction: gyrolite-Ca0 + Mex+ ↔ gyrolite-Me0 + Ca2+. It was observed that the pseudo second order model fit well for iron and nickel ions adsorption mechanism. It was estimated that the adsorption reactions are not reversible process and the crystal structure of gyrolite is stable. Moreover, synthetic adsorbent and the products of sorption were characterized by XRD, STA and FT-IR methods.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.5735

Enhanced photoelectrocatalytic performance of α-Fe2O3 thin films by surface plasmon resonance of Au nanoparticles coupled with surface passivation by atom layer deposition of Al2O3.

Science.gov (United States)

Liu, Yuting; Xu, Zhen; Yin, Min; Fan, Haowen; Cheng, Weijie; Lu, Linfeng; Song, Ye; Ma, Jing; Zhu, Xufei

2015-12-01

The short lifetime of photogenerated charge carriers of hematite (α-Fe2O3) thin films strongly hindered the PEC performances. Herein, α-Fe2O3 thin films with surface nanowire were synthesized by electrodeposition and post annealing method for photoelectrocatalytic (PEC) water splitting. The thickness of the α-Fe2O3 films can be precisely controlled by adjusting the duration of the electrodeposition. The Au nanoparticles (NPs) and Al2O3 shell by atom layer deposition were further introduced to modify the photoelectrodes. Different constructions were made with different deposition orders of Au and Al2O3 on Fe2O3 films. The Fe2O3-Au-Al2O3 construction shows the best PEC performance with 1.78 times enhancement by localized surface plasmon resonance (LSPR) of NPs in conjunction with surface passivation of Al2O3 shells. Numerical simulation was carried out to investigate the promotion mechanisms. The high PEC performance for Fe2O3-Au-Al2O3 construction electrode could be attributed to the Al2O3 intensified LSPR, effective surface passivation by Al2O3 coating, and the efficient charge transfer due to the Fe2O3-Au Schottky junctions.

Thermodynamic Constraints in Using AuM (M = Fe, Co, Ni, and Mo) Alloys as N₂ Dissociation Catalysts: Functionalizing a Plasmon-Active Metal.

Science.gov (United States)

Martirez, John Mark P; Carter, Emily A

2016-02-23

The Haber-Bosch process for NH3 synthesis is arguably one of the greatest inventions of the 20th century, with a massive footprint in agriculture and, historically, warfare. Current catalysts for this reaction use Fe for N2 activation, conducted at high temperatures and pressures to improve conversion rate and efficiency. A recent finding shows that plasmonic metal nanoparticles can either generate highly reactive electrons and holes or induce resonant surface excitations through plasmonic decay, which catalyze dissociation and redox reactions under mild conditions. It is therefore appealing to consider AuM (M = Fe, Co, Ni, and Mo) alloys to combine the strongly plasmonic nature of Au and the catalytic nature of M metals toward N2 dissociation, which together might facilitate ammonia production. To this end, through density functional theory, we (i) explore the feasibility of forming these surface alloys, (ii) find a pathway that may stabilize/deactivate surface M substituents during fabrication, and (iii) define a complementary route to reactivate them under operational conditions. Finally, we evaluate their reactivity toward N2, as well as their ability to support a pathway for N2 dissociation with a low thermodynamic barrier. We find that AuFe possesses similar appealing qualities, including relative stability with respect to phase separation, reversibility of Fe oxidation and reduction, and reactivity toward N2. While AuMo achieves the best affinity toward N2, its strong propensity toward oxidation could greatly limit its use.

Coprecipitation of gold(III) complex ions with manganese(II) hydroxide and their stoichiometric reduction to atomic gold (Au(0)): analysis by Mössbauer spectroscopy and XPS.

Science.gov (United States)

Yamashita, Mamiko; Ohashi, Hironori; Kobayashi, Yasuhiro; Okaue, Yoshihiro; Kurisaki, Tsutomu; Wakita, Hisanobu; Yokoyama, Takushi

2008-03-01

To elucidate the formation process of precursor of gold-supported manganese dioxide (MnO2), the coprecipitation behavior of [AuCl4-n(OH)n](-) (n=0-4) (Au(III)) complex ions with manganese(II) hydroxide (Mn(OH)2 and the change in their chemical state were examined. The Au(III) complex ions were rapidly and effectively coprecipitated with Mn(OH)(2) at pH 9. According to the Mössbauer spectra for gold (Au) coprecipitated with Mn(OH)2, below an Au content of 60 wt% in the coprecipitates, all of the coprecipitated Au existed in the atomic state (Au(0)), while, above an Au content of 65 wt%, part of the gold existed in the Au(III) state, and the proportion increased with increasing coprecipitated Au content. Based on the results of X-ray photoelectron spectroscopy, Mn(II) in Mn(OH)2 converted to Mn(IV) in conjunction with coprecipitation of Au(III) complex ions. These results indicate that the rapid stoichiometric reduction of Au(III) to Au(0) is caused by electron transfer from Mn(II) in Mn(OH)2 to the Au(III) complex ion through an Mn-O-Au bond.

Spin crossover behaviour in Hofmann-like coordination polymer Fe(py)2[Pd(CN)4] with 57Fe Mössbauer spectra

Science.gov (United States)

Kitazawa, Takafumi; Kishida, Takanori; Kawasaki, Takeshi; Takahashi, Masashi

2017-11-01

We have prepared the 2D spin crossover complexes Fe(L)2Pd(CN)4 (L = py : 1a; py-D5 : 1b and py-15N : 1c). 1a has been characterised by 57Fe Mossbauer spectroscopic measurements, single crystal X-ray determination and SQUID measurements. The Mössbauer spectra for 1a indicate that the iron(II) spin states are in high spin states at 298 K and are in low spin states at 77 K. The crystal structures of 1a at 298 K and 90 K also show the high spin state and the low spin state respectively, associated with the Fe(II)-N distances. The spin transition temperature range of 1a is higher than that of Fe(py)2Ni(CN)4 since Pd(II) ions are larger and heavier than Ni(II) ions. SQUID data indicate isotope effects among 1a, 1b and 1c are observed in very small shifts of the transition temperatures probably due to larger and heavier Pd(II) ions. The delicate shifts would be associated with subtle balances between different vibrations around Fe(II) atoms and electronic factors.

Focused-ion-beam induced interfacial intermixing of magnetic bilayers for nanoscale control of magnetic properties

International Nuclear Information System (INIS)

Burn, D M; Atkinson, D; Hase, T P A

2014-01-01

Modification of the magnetic properties in a thin-film ferromagnetic/non-magnetic bilayer system by low-dose focused ion-beam (FIB) induced intermixing is demonstrated. The highly localized capability of FIB may be used to locally control magnetic behaviour at the nanoscale. The magnetic, electronic and structural properties of NiFe/Au bilayers were investigated as a function of the interfacial structure that was actively modified using focused Ga + ion irradiation. Experimental work used MOKE, SQUID, XMCD as well as magnetoresistance measurements to determine the magnetic behavior and grazing incidence x-ray reflectivity to elucidate the interfacial structure. Interfacial intermixing, induced by low-dose irradiation, is shown to lead to complex changes in the magnetic behavior that are associated with monotonic structural evolution of the interface. This behavior may be explained by changes in the local atomic environment within the interface region resulting in a combination of processes including the loss of moment on Ni and Fe, an induced moment on Au and modifications to the spin-orbit coupling between Au and NiFe. (paper)

Analysis of the intermediate stage in the heavy ion interactions of {sup 208}Pb+{sup 197}Au and {sup 197}Au+{sup 197}Au

Energy Technology Data Exchange (ETDEWEB)

Nasir, Tabassum [Department of Physics, Gomal University D.I. Khan (Pakistan); Khan, E.U. [Department of Physics, CIIT, Islamabad (Pakistan)], E-mail: ehsan@comsats.edu.pk; Baluch, J J [Department of Environmental Sciences, CIIT, Abbottabad (Pakistan); Qureshi, I E [Pakistan Atomic Energy Commission, P.O. Box 1114, Islamabad (Pakistan); Sajid, M; Shahzad, M I [Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)

2008-08-15

Two different projectiles {sup 208}Pb and {sup 197}Au at the same energy (11.67MeV/u) have been bombarded on {sup 197}Au target to study heavy ion interactions using mica as a passive detector. In this paper we present results on the study of energy damping and time scale of the existence of di-nuclear composite system in the intermediate reaction step. The plots of Q-values as well as reaction cross sections in various angular bins of scattering angles suggest that K.E. damping was complete and dynamic equilibrium was established between the first and second reaction steps. The time scale of this duration was also determined.

Intrinsically superparamagnetic Fe-hydroxyapatite nanoparticles positively influence osteoblast-like cell behaviour

Science.gov (United States)

2012-01-01

Background Superparamagnetic nanoparticles (MNPs) have been progressively explored for their potential in biomedical applications and in particular as a contrast agent for diagnostic imaging, for magnetic drug delivery and more recently for tissue engineering applications. Considering the importance of having safe MNPs for such applications, and the essential role of iron in bone remodelling, this study developed and analysed novel biocompatible and bioreabsorbable superparamagnetic nanoparticles, that avoid the use of poorly tolerated magnetite based nanoparticles, for bone tissue engineering applications. Results MNPs were obtained by doping hydroxyapatite (HA) with Fe ions, by directly substituting Fe2+ and Fe3+ into the HA structure yielding superparamagnetic bioactive phase. In the current study, we have investigated the effects of increasing concentrations (2000 μg/ml; 1000 μg/ml; 500 μg/ml; 200 μg/ml) of FeHA MNPs in vitro using Saos-2 human osteoblast-like cells cultured for 1, 3 and 7 days with and without the exposure to a static magnetic field of 320 mT. Results demonstrated not only a comparable osteoblast viability and morphology, but increased in cell proliferation, when compared to a commercially available Ha nanoparticles, even with the highest dose used. Furthermore, FeHA MNPs exposure to the static magnetic field resulted in a significant increase in cell proliferation throughout the experimental period, and higher osteoblast activity. In vivo preliminary results demonstrated good biocompatibility of FeHA superparamagnetic material four weeks after implantation into a critical size lesion of the rabbit condyle. Conclusions The results of the current study suggest that these novel FeHA MNPs may be particularly relevant for strategies of bone tissue regeneration and open new perspectives for the application of a static magnetic field in a clinical setting of bone replacement, either for diagnostic imaging or magnetic drug delivery

Pershore made CR-39(DOP) as a 1.015 GeV/n 197Au-ion detector

International Nuclear Information System (INIS)

Bhattacharyya, D.P.; Chakrabarty, S.; Rakshit, R.; Basu, B.; Pal, P.; Biswas, S.

1993-01-01

Pershore made CR-39(DOP) stack was exposed at a zenith angle of 30deg by 197 Au-ions of energy 1.015 GeV/n using LBL BEVALAC beam. The top of the irradiated plate of the stack has been etched in 6.25N NaOH solution at 70degC for one hour. About 1202 cone lengths were optically measured. The estimated etch rate ratio of the incident 197 Au projectile beam in CR-39 has been found to be 27±2. The result has been compared with earlier observation. The charge resolution of the detector has been estimated from the average of double cone lengths and has been found to have a value of (0.58±0.03)e for 197 Au-ions. (orig.)

Partitioning and structural role of Mn and Fe ions in ionic sulfophosphate glasses

International Nuclear Information System (INIS)

Möncke, Doris; Wondraczek, Lothar; Sirotkin, Sergey; Stavrou, Elissaios; Kamitsos, Efstratios I.

2014-01-01

Ionic sulfophosphate liquids of the type ZnO-Na 2 O-Na 2 SO 4 -P 2 O 5 exhibit surprising glass forming ability, even at slow or moderate cooling rate. As a concept, they also provide high solubility of transition metal ions which could act as cross-linking sites between the sulfate and phosphate entities. It is therefore investigated how the replacement of ZnO by MnO and/or FeO affects the glass structure and the glass properties. Increasing manganese levels are found to result in a monotonic increase of the transition temperature T g and most of the mechanical properties. This trend is attributed to the change of metal-ion coordination from four-fold around Zn 2+ to six-fold around Mn 2+ ions. The higher coordination facilitates cross-linking of the ionic structural entities and subsequently increases T g . Raman and infrared spectroscopy show that the structure of these glasses involves only SO 4 2− and PO 4 3− monomers as well as P 2 O 7 4- dimers. Replacement of ZnO by MnO is found to favour PO 4 3− over P 2 O 7 4- species, a trend which is enhanced by co-doping with FeO. Both transition metal ions show, like Zn 2+ , a preference to selectively coordinate to phosphate anionic species, as opposed to sodium ions which coordinate mainly to sulfate anions. EPR spectroscopy finally shows that divalent Mn 2+ ions are present primarily in MnO 6 -clusters, which, in the studied sulfophosphate glasses, convert upon increasing MnO content from corner-sharing to edge-sharing entities

Porous Fe2O3 Microspheres as Anode for Lithium-Ion Batteries

Science.gov (United States)

Noerochim, L.; Indra, M. A. T.; Purwaningsih, H.; Subhan, A.

2018-05-01

In this work, Fe2O3 was successfully synthesized by the hydrothermal process at low temperature. FeCl3.6H2O as precursor and variation of lysine as hydrolyzing agent were used to preparing Fe2O3. SEM images show that the morphology of Fe2O3 is porous microsphere with sizes in the range of (1 to 5) µm in diameter. The as-prepared Fe2O3 with the 2 M of lysine exhibits excellent cycling performance when used as the anode for lithium ion batteries, obtaining reversible discharge capacity of 172.33 mA·h·g‑1 at 0.5 C after 50 cycles. It is attributed to the unique structure of porous microspheres providing a large surface area which maintains good electronic contact between particles during charge-discharge process. This result demonstrates that Fe2O3 porous microsphere has a high potential as anode material for application of lithium-ion battery.

Energy Dependence of Elliptic Flow over a Large Pseudorapidity Range in Au+Au Collisions at the BNL Relativistic Heavy Ion Collider

Science.gov (United States)

Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Hauer, M.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Seals, H.; Sedykh, I.; Skulski, W.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S.; Sukhanov, A.; Tang, J.-L.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Wenger, E.; Wolfs, F. L.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

2005-04-01

This Letter describes the measurement of the energy dependence of elliptic flow for charged particles in Au+Au collisions using the PHOBOS detector at the Relativistic Heavy Ion Collider. Data taken at collision energies of √(sNN)=19.6, 62.4, 130, and 200 GeV are shown over a wide range in pseudorapidity. These results, when plotted as a function of η'=|η|-ybeam, scale with approximate linearity throughout η', implying no sharp changes in the dynamics of particle production as a function of pseudorapidity or increasing beam energy.

Surface damage in TEM thick α-Fe samples by implantation with 150 keV Fe ions

International Nuclear Information System (INIS)

Aliaga, M.J.; Caturla, M.J.; Schäublin, R.

2015-01-01

We have performed molecular dynamics simulations of implantation of 150 keV Fe ions in pure bcc Fe. The thickness of the simulation box is of the same order of those used in in situ TEM analysis of irradiated materials. We assess the effect of the implantation angle and the presence of front and back surfaces. The number and type of defects, ion range, cluster distribution and primary damage morphology are studied. Results indicate that, for the very thin samples used in in situ TEM irradiation experiments the presence of surfaces affect dramatically the damage produced. At this particular energy, the ion has sufficient energy to damage both the top and the back surfaces and still leave the sample through the bottom. This provides new insights on the study of radiation damage using TEM in situ

Improvement of in vitro corrosion and cytocompatibility of biodegradable Fe surface modified by Zn ion implantation

Energy Technology Data Exchange (ETDEWEB)

Wang, Henan; Zheng, Yang; Li, Yan, E-mail: liyan@buaa.edu.cn; Jiang, Chengbao

2017-05-01

Highlights: • Fe{sub 2}O{sub 3}/ZnO oxides were formed on the surface of Zn implanted pure Fe samples. • The corrosion rate of the pure Fe in SBF was increased after Zn implantation. • Cytocompatibility of the pure Fe was improved by Zn ion implantation. - Abstract: Pure Fe was surface-modified by Zn ion implantation to improve the biodegradable behavior and cytocompatibility. Surface topography, chemical composition, corrosion resistance and cytocompatibility were investigated. Atomic force microscopy, auger electron spectroscopy and X-ray photoelectron spectroscopy results showed that Zn was implanted into the surface of pure Fe in the depth of 40–60 nm and Fe{sub 2}O{sub 3}/ZnO oxides were formed on the outmost surface. Electrochemical measurements and immersion tests revealed an improved degradable behavior for the Zn-implanted Fe samples. An approximately 12% reduction in the corrosion potential (E{sub corr}) and a 10-fold increase in the corrosion current density (i{sub corr}) were obtained after Zn ion implantation with a moderate incident ion dose, which was attributed to the enhanced pitting corrosion. The surface free energy of pure Fe was decreased by Zn ion implantation. The results of direct cell culture indicated that the short-term (4 h) cytocompatibility of MC3T3-E1 cells was promoted by the implanted Zn on the surface.

Efficiency of Chitosan for the Removal of Pb (II, Fe (II and Cu (II Ions from Aqueous Solutions

Directory of Open Access Journals (Sweden)

Soheil Sobhanardakani

2014-09-01

Full Text Available Background: Heavy metals have been recognized as harmful environmental pollutant known to produce highly toxic effects on different organs and systems of both humans and animals. The aim of this paper is to evaluate the adsorption potential of chitosan for the removal of Pb(II, Fe(II and Cu(II ions from aqueous solutions. Methods: This study was conducted in laboratory scale. In this paper chitosan has been used as an adsorbent for the removal of Pb(II, Fe(II and Cu(II from aqueous solution. In batch tests, the effects of parameters like pH solution (1.0-8.0, initial metal concentrations (100-1000 mgL-1, contact time (5.0-150 min and adsorbent dose (1.0-7.0 g on the adsorption process were studied. Results: The results showed that the adsorption of Pb(II, Fe(II and Cu(II ions on chitosan strongly depends on pH. The experimental isothermal data were analyzed using the Langmuir and Freundlich equations and it was found that the removal process followed the Langmuir isotherm and maximum adsorption capacity for the adsorption of Pb(II, Fe(II and Cu(II ions by the chitosan were 55.5mg g−1, 71.4 mg g−1 and 59 mg g−1, respectively, under equilibrium conditions at 25±1 ºC. The adsorption process was found to be well described by the pseudo-second-order rate model. Conclusion: The obtained results showed that chitosan is a readily, available, economic adsorbent and was found suitable for removing Pb(II, Fe(II and Cu(II ions from aqueous solution.

Relative Biological Effectiveness of HZE Fe Ions for Induction ofMicro-Nuclei at Low Doses

Energy Technology Data Exchange (ETDEWEB)

Groesser, Torsten; Chun, Eugene; Rydberg, Bjorn

2007-01-16

Dose-response curves for induction of micro-nuclei (MN) was measured in Chinese hamster V79 and xrs6 (Ku80-) cells and in human mammary epithelial MCF10A cells in the dose range of 0.05-1 Gy. The Chinese Hamster cells were exposed to 1 GeV/u Fe ions, 600 MeV/u Fe ions, and 300 MeV/u Fe ions (LETs of 151, 176 and 235 keV/{micro}m respectively) as well as with 320 kVp X-rays as reference. Second-order polynomials were fitted to the induction curves and the initial slopes (the alpha values) were used to calculate RBE. For the repair proficient V79 cells the RBE at these low doses increased with LET. The values obtained were 3.1 (LET=151 keV/{micro}m), 4.3 (LET = 176 keV/{micro}m) and 5.7 (LET = 235 keV/{micro}m), while the RBE was close to 1 for the repair deficient xrs6 cells regardless of LET. For the MCF10A cells the RBE was determined for 1 GeV/u Fe ions and found to be 5.4, slightly higher than for V79 cells. To test the effect of shielding, the 1 GeV/u Fe ion beam was intercepted by various thickness of high-density polyethylene plastic absorbers, which resulted in energy loss and fragmentation. It was found that the MN yield for V79 cells placed behind the absorbers decreased in proportion to the decrease in dose both before and after the Fe ion Bragg peak (excluding the area around the Fe-ion Bragg peak itself), indicating that RBE did not change significantly due to shielding. At the Bragg peak the effectiveness for MN formation per unit dose was decreased, indicating an 'overkill' effect by low-energy very high-LET Fe ions.

Ion beam texturing

Science.gov (United States)

Hudson, W. R.

1977-01-01

A microscopic surface texture was created by sputter-etching a surface while simultaneously sputter-depositing a lower sputter yield material onto the surface. A xenon ion-beam source was used to perform the texturing process on samples as large as 3-cm diameter. Textured surfaces have been characterized with SEM photomicrographs for a large number of materials including Cu, Al, Si, Ti, Ni, Fe, stainless steel, Au, and Ag. A number of texturing parameters are studied including the variation of texture with ion-beam powder, surface temperature, and the rate of texture growth with sputter etching time.

A rapid green strategy for the synthesis of Au "meatball"-like nanoparticles using green tea for SERS applications

Science.gov (United States)

Wu, Shichao; Zhou, Xi; Yang, Xiangrui; Hou, Zhenqing; Shi, Yanfeng; Zhong, Lubin; Jiang, Qian; Zhang, Qiqing

2014-09-01

We report a simple and rapid biological approach to synthesize water-soluble and highly roughened "meatball"-like Au nanoparticles using green tea extract under microwave irradiation. The synthesized Au meatball-like nanoparticles possess excellent monodispersity and uniform size (250 nm in diameter). Raman measurements show that these tea-generated meatball-like gold nanostructures with high active surface areas exhibit a high enhancement of surface-enhanced Raman scattering. In addition, the Au meatball-like nanoparticles demonstrate good biocompatibility and remarkable in vitro stability at the biological temperature. Meanwhile, the factors that influence the Au meatball-like nanoparticles morphology are investigated, and the mechanisms behind the nonspherical shape evolution are discussed.

Acridine-based fluorescence chemosensors for selective sensing of Fe3+ and Ni2+ ions

Science.gov (United States)

Wang, Chaoyu; Fu, Jiaxin; Yao, Kun; Xue, Kun; Xu, Kuoxi; Pang, Xiaobin

2018-06-01

Two novel acridine-based fluorescence chemosensors (L1 and L2) were prepared and their metal ions sensing properties were investigated. L1 (L2) exhibited an excellent selective fluorescence response toward Fe3+ (Ni2+) and the stoichiometry ratio of L1-Fe3+ and L2-Ni2+ were 1:1. The detection limits of L1 and L2 were calculated by the fluorescence titration to be 4.13 μM and 1.52 μM, respectively, which were below the maximum permissive level of Fe3+ and Ni2+ ions in drinking water set by the EPA. The possible mechanism of the fluorescence detection of Fe3+ and Ni2+ had been proposed according to the analysis of Job's plot, IR spectra and ESI-MS. The determination of Fe3+ and Ni2+ ions in living cells had been applied successfully.

Electrochemistry of carbonaceous materials; 1. Oxidation of Sardinian coal by Fe(III) ions

Energy Technology Data Exchange (ETDEWEB)

Tomat, R.; Salmaso, R.; Zecchin, S. (CNR-Instituto di Polarografia ed Elettrochimica Preparativa, Padova (Italy))

1992-04-01

Oxidation of subbitiminous coal (Sulcis basin, Sardinia, Italy) by Fe(III) ions in aqueous H{sub 2}SO{sub 4} solution was investigated over a wide temperature range (20-80{degree}C). Experimental results are in accord with a reaction scheme involving a reversible complex between coal particles and Fe(III) ions as a first step in the oxidation process. At low coal concentration, the reaction rate follows first-order kinetics in both coal and ferric ions (overall second order), while at sufficiently high coal concentration, the reaction rate is consistent with first-order kinetics in Fe(III) concentration, appearing to be independent of coal concentration. The kinetic results obtained give preliminary information on the advantageous use of the Fe(III)/slurried coal reaction system to depolarize the anodic compartment of an electrolysis cell, for the production of H{sub 2}. 11 refs., 5 figs.

Effects of swift heavy ion irradiation on the electrical characteristics of Au/n-GaAs Schottky diodes

International Nuclear Information System (INIS)

Sharma, A. Tarun; Shahnawaz; Kumar, Sandeep; Katharria, Yashpal S.; Kanjilal, Dinakar

2007-01-01

Metal-semiconductor diode of Au/n-GaAs is studied under the irradiation of swift heavy ion (SHI) beam (80 MeV 16 O 6+ ), using in situ current-voltage characterization technique. The diode parameters like ideality factor, barrier height, and leakage current are observed to vary with irradiation fluence. Significantly, the diode performance improves at a high fluence of 2 x 10 13 ions cm -2 with a large decrease of reverse leakage current in comparison to the original as deposited sample. The Schottky barrier height (SBH) also increases with fluence. At a high irradiation fluence of 5 x 10 13 ions cm -2 the SBH (0.62 ± 0.01 eV) is much larger than that of the as deposited sample (0.55 ± 0.01 eV). The diode parameters remain stable over a large range of irradiation up to fluence of 8 x 10 13 ions cm -2 . A prominent annealing effect of the swift ion beam owing to moderate electronic excitation and high ratio of electronic energy loss to the nuclear loss is found to be responsible for the improvement in diode characteristics

Discovery of Suprathermal Fe+ in and near Earth's Magnetosphere

Science.gov (United States)

Christon, S. P.; Hamilton, D. C.; Plane, J. M. C.; Mitchell, D. G.; Grebowsky, J. M.; Spjeldvik, W. N.; Nylund, S. R.

2017-12-01

Suprathermal (87-212 keV/e) singly charged iron, Fe+, has been observed in and near Earth's equatorial magnetosphere using long-term ( 21 years) Geotail/STICS ion composition data. Fe+ is rare compared to dominant suprathermal solar wind and ionospheric origin heavy ions. Earth's suprathermal Fe+ appears to be positively associated with both geomagnetic and solar activity. Three candidate lower-energy sources are examined for relevance: ionospheric outflow of Fe+ escaped from ion layers altitude, charge exchange of nominal solar wind Fe+≥7, and/or solar wind transported inner source pickup Fe+ (likely formed by solar wind Fe+≥7 interaction with near sun interplanetary dust particles, IDPs). Semi-permanent ionospheric Fe+ layers form near 100 km altitude from the tons of IDPs entering Earth's atmosphere daily. Fe+ scattered from these layers is observed up to 1000 km altitude, likely escaping in strong ionospheric outflows. Using 26% of STICS's magnetosphere-dominated data at low-to-moderate geomagnetic activity levels, we demonstrate that solar wind Fe charge exchange secondaries are not an obvious Fe+ source then. Earth flyby and cruise data from Cassini/CHEMS, a nearly identical instrument, show that inner source pickup Fe+ is likely not important at suprathermal energies. Therefore, lacking any other candidate sources, it appears that ionospheric Fe+ constitutes at least an important portion of Earth's suprathermal Fe+, comparable to observations at Saturn where ionospheric origin suprathermal Fe+ has also been observed.

Na{sub 2}EDTA-assisted hydrothermal synthesis and electrochemical performance of LiFePO{sub 4} powders with rod-like and block-like morphologies

Energy Technology Data Exchange (ETDEWEB)

Wang, Juan, E-mail: juanwang168@gmail.com [Shaanxi Key Laboratory of Nanomaterials and Nanotechnology, Xi' an University of Architecture and Technology, Xi' an 710055 (China); Zheng, Siqi; Yan, Hao; Zhang, Haipeng [Shaanxi Key Laboratory of Nanomaterials and Nanotechnology, Xi' an University of Architecture and Technology, Xi' an 710055 (China); Hojamberdiev, Mirabbos [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama, Kanagawa 226-8503 (Japan); Ren, Bing; Xu, Yunhua [Shaanxi Key Laboratory of Nanomaterials and Nanotechnology, Xi' an University of Architecture and Technology, Xi' an 710055 (China)

2015-06-15

Nano and micro-sized LiFePO{sub 4} were synthesized by disodium ethylenediamine tetraacetate (Na{sub 2}EDTA) – assisted hydrothermal synthesis method with the pH of synthesizing solution in the range from 2 to 8. The as-synthesized samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and electrochemical performance experiments. The obtained results showed that the pH of synthesizing solution played a key role in the formation of the final products with different morphologies, including rod-like and block-like structures and so on. The formation mechanism and the influence of Na{sub 2}EDTA on the morphology of LiFePO{sub 4} micro- and nanocrystals were investigated as a function of pH value. The results of electrochemical performance measurement revealed that the charge/discharge cycling characteristics of the samples were varied by tailoring their morphologies. Particularly, the block-like LiFePO{sub 4} particles with the average size of 200–600 nm present the highest initial discharge capacity of 141 mAh/g at 0.1C rate, and cycling stability of this sample is optimal among all the obtained products owing to its good diffusion properties. It also exhibits an excellent rate capability with high discharge capacities of more than 93.2 mAh/g at 5C after 80 cycles. The present study offers a simple way to synthesize and design high performance cathode materials for lithium-ion batteries by the methods of morphology control without carbon coating or doping with supervalent cations. - Highlights: • Nano and micro-sized LiFePO{sub 4} were synthesized by a hydrothermal synthesis method. • Effect of the pH of synthesizing solution on the formation of LiFePO{sub 4} was studied. • The block-like LiFePO{sub 4} particles present the highest initial discharge capacity. • The rate capability of the block-like LiFePO{sub 4} is more than 93.2 m

The Impact of Template Types on Polyeugenol to the Adsorption Selectivity of Ionic Imprinted Polymer (IIP) Fe Metal Ion

Science.gov (United States)

Djunaidi, M. C.; Haris, A.; Pardoyo; Rosdiana, K.

2018-04-01

The synthesis of IIP was carried out by variation of Fe(III) ion templates from Fe(NO3)3, K3[Fe(CN)6] and NH4Fe(SO4)2 compounds which then tested IIP selectivity to the Fe metal ions through adsorption process. Ionic Imprinted Polymer (IIP) is a method of printing metal ions bound in a polymer, subsequently released from the polymer matrix to produce a suitable imprint for the target ion. The purposes of this study were to produce IIP from Fe(NO3)3, K3[Fe(CN)6] and NH4Fe(SO4)2 templates, to know the effect of templates on adsorption selectivity of IIP involving imprint cavity, and to know the impact of metal competitor on the selectivity adsorption of IIP to the Fe metals. The results obtained showed that IIP synthesized by variations of Fe(NO3)3, K3[Fe(CN)6] and NH4Fe(SO4)2 templates were successfully synthesized. The adsorption selectivity of Fe (III) metal ion in the Fe(NO3)3 template was greater than that of in the K3[Fe(CN)6] and NH4Fe(SO4)2 templates. The adsorption selectivity of Fe was greater on Fe-Cr compared to on Fe-Cd and Fe-Pb.

Environmental application of millimetre-scale sponge iron (s-Fe{sup 0}) particles (IV): New insights into visible light photo-Fenton-like process with optimum dosage of H{sub 2}O{sub 2} and RhB photosensitizers

Energy Technology Data Exchange (ETDEWEB)

Ju, Yongming, E-mail: juyongming@scies.org [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Innovative Laboratory for Environmental Functional Materials and Environmental Applications of Microwave Irradiation, South China Subcenter of State Environmental Dioxin Monitoring Center, Guangzhou 510655 (China); Guangdong Key Laboratory of Agro-Environment Integrated Control, South China Institute of Environmental Sciences, Guangzhou 510655 (China); Yu, Yunjiang, E-mail: yuyunjiang@scies.org [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Wang, Xiaoyan; Xiang, Mingdeng; Li, Liangzhong [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Deng, Dongyang [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Innovative Laboratory for Environmental Functional Materials and Environmental Applications of Microwave Irradiation, South China Subcenter of State Environmental Dioxin Monitoring Center, Guangzhou 510655 (China); Guangdong Key Laboratory of Agro-Environment Integrated Control, South China Institute of Environmental Sciences, Guangzhou 510655 (China); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering (DBCEE), University of Cincinnati, Cincinnati, Ohio, 45221-0012 (United States)

2017-02-05

Highlights: • Synergistic action of Rhodamine B (RhB), visible light, H{sub 2}O{sub 2} and s-Fe{sup 0} is essential. • The complexes of RhB and Fe{sup 3+} eject one electron via ligand-to-metal charge-transfer. • RhB assists the photo-Fenton-like removal of tetrabromobisphenol A (TBBPA). - Abstract: In this study, we firstly develop the photo-Fenton-like system with millimetric sponge iron (s-Fe{sup 0}), H{sub 2}O{sub 2}, visible light (vis, λ ≥ 420 nm) and rhodamine B (RhB), and present a comprehensive study concerning the mechanism. Thus, we investigate (1) the adsorption of RhB onto s-Fe{sup 0}, (2) the photo-Fenton-like removal of RhB over iron oxides generated from the corrosion of s-Fe{sup 0}, (3) the homogeneous photo-Fenton removal of RhB over Fe{sup 2+} or Fe{sup 3+}, (4) the Fe{sup 3+}-RhB complexes, and (5) the photo-Fenton-like removal of tetrabromobisphenol A (TBBPA). The results show that neither the adsorption process over s-Fe{sup 0} nor the photo-Fenton-like process over FeOOH, Fe{sub 3}O{sub 4} and Fe{sub 2}O{sub 3}, achieved efficient removal of RhB. For comparison, in homogeneous photo-Fenton process, the presence of Fe{sup 3+} ions, rather than Fe{sup 2+} ions, effectively eliminated RhB. Furthermore, the UV–vis spectra showing new absorbance at ∼ 285 nm indicate the complexes of RhB and Fe{sup 3+} ions, adopting vis photons to form excited state and further eject one electron via ligand-to-metal charge-transfer to activate H{sub 2}O{sub 2}. Additionally, efficient TBBPA removal was obtained only in the presence of RhB. Accordingly, the s-Fe{sup 0}– based photo-Fenton-like process assisted with dyestuff wastewater is promising for removing a series of persistent organic pollutants.

A Core-Shell Fe/Fe2 O3 Nanowire as a High-Performance Anode Material for Lithium-Ion Batteries.

Science.gov (United States)

Na, Zhaolin; Huang, Gang; Liang, Fei; Yin, Dongming; Wang, Limin

2016-08-16

The preparation of novel one-dimensional core-shell Fe/Fe2 O3 nanowires as anodes for high-performance lithium-ion batteries (LIBs) is reported. The nanowires are prepared in a facile synthetic process in aqueous solution under ambient conditions with subsequent annealing treatment that could tune the capacity for lithium storage. When this hybrid is used as an anode material for LIBs, the outer Fe2 O3 shell can act as an electrochemically active material to store and release lithium ions, whereas the highly conductive and inactive Fe core functions as nothing more than an efficient electrical conducting pathway and a remarkable buffer to tolerate volume changes of the electrode materials during the insertion and extraction of lithium ions. The core-shell Fe/Fe2 O3 nanowire maintains an excellent reversible capacity of over 767 mA h g(-1) at 500 mA g(-1) after 200 cycles with a high average Coulombic efficiency of 98.6 %. Even at 2000 mA g(-1) , a stable capacity as high as 538 mA h g(-1) could be obtained. The unique composition and nanostructure of this electrode material contribute to this enhanced electrochemical performance. Due to the ease of large-scale fabrication and superior electrochemical performance, these hybrid nanowires are promising anode materials for the next generation of high-performance LIBs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Amperometric glucose sensor based on enhanced catalytic reduction of oxygen using glucose oxidase adsorbed onto core-shell Fe{sub 3}O{sub 4}-silica-Au magnetic nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Wang Aijun [College of Geography and Environmental Science, College of Chemistry and Life Science, Zhejiang Normal University, Jinhua 321004 (China); Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Environmental Science, Henan Normal University, Xinxiang 453007 (China); Li Yongfang [College of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang 453003 (China); Li Zhonghua [Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Environmental Science, Henan Normal University, Xinxiang 453007 (China); Feng Jiuju, E-mail: jjfengnju@gmail.com [College of Geography and Environmental Science, College of Chemistry and Life Science, Zhejiang Normal University, Jinhua 321004 (China); Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Environmental Science, Henan Normal University, Xinxiang 453007 (China); Sun Yanli [Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Environmental Science, Henan Normal University, Xinxiang 453007 (China); Chen Jianrong [College of Geography and Environmental Science, College of Chemistry and Life Science, Zhejiang Normal University, Jinhua 321004 (China)

2012-08-01

Monodisperse Fe{sub 3}O{sub 4} magnetic nanoparticles (NPs) were prepared under facile solvothermal conditions and successively functionalized with silica and Au to form core/shell Fe{sub 3}O{sub 4}-silica-Au NPs. Furthermore, the samples were used as matrix to construct a glucose sensor based on glucose oxidase (GOD). The immobilized GOD retained its bioactivity with high protein load of 3.92 Multiplication-Sign 10{sup -9} mol{center_dot}cm{sup -2}, and exhibited a surface-controlled quasi-reversible redox reaction, with a fast heterogeneous electron transfer rate of 7.98 {+-} 0.6 s{sup -1}. The glucose biosensor showed a broad linear range up to 3.97 mM with high sensitivity of 62.45 {mu}A{center_dot}mM{sup -1} cm{sup -2} and fast response (less than 5 s). - Graphical abstract: Core-shell structured Fe{sub 3}O{sub 4}-silica-Au nanoparticles were prepared and used as matrix to construct an amperometric glucose sensor based on glucose oxidase, which showed broad linear range, high sensitivity, and fast response. Highlights: Black-Right-Pointing-Pointer Synthesis of monodispersed Fe{sub 3}O{sub 4} nanoparticles. Black-Right-Pointing-Pointer Fabrication of core/shell Fe{sub 3}O{sub 4}-silica-Au nanoparticles. Black-Right-Pointing-Pointer Construction of a novel glucose sensor with wide linear range, high sensitivity and fast response.

Partitioning and structural role of Mn and Fe ions in ionic sulfophosphate glasses

Energy Technology Data Exchange (ETDEWEB)

Möncke, Doris; Wondraczek, Lothar, E-mail: lothar.wondraczek@uni-jena.de [Otto-Schott-Institute of Materials Research, Friedrich-Schiller-University Jena, Fraunhoferstr. 6, 07743 Jena (Germany); Sirotkin, Sergey [Institut des Sciences Moléculaires - CNRS UMR 5255, Université de Bordeaux, 33405 Talence (France); Stavrou, Elissaios; Kamitsos, Efstratios I. [Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constaniou Ave., 116 35 Athens (Greece)

2014-12-14

Ionic sulfophosphate liquids of the type ZnO-Na{sub 2}O-Na{sub 2}SO{sub 4}-P{sub 2}O{sub 5} exhibit surprising glass forming ability, even at slow or moderate cooling rate. As a concept, they also provide high solubility of transition metal ions which could act as cross-linking sites between the sulfate and phosphate entities. It is therefore investigated how the replacement of ZnO by MnO and/or FeO affects the glass structure and the glass properties. Increasing manganese levels are found to result in a monotonic increase of the transition temperature T{sub g} and most of the mechanical properties. This trend is attributed to the change of metal-ion coordination from four-fold around Zn{sup 2+} to six-fold around Mn{sup 2+} ions. The higher coordination facilitates cross-linking of the ionic structural entities and subsequently increases T{sub g}. Raman and infrared spectroscopy show that the structure of these glasses involves only SO{sub 4}{sup 2−} and PO{sub 4}{sup 3−} monomers as well as P{sub 2}O{sub 7}{sup 4-} dimers. Replacement of ZnO by MnO is found to favour PO{sub 4}{sup 3−} over P{sub 2}O{sub 7}{sup 4-} species, a trend which is enhanced by co-doping with FeO. Both transition metal ions show, like Zn{sup 2+}, a preference to selectively coordinate to phosphate anionic species, as opposed to sodium ions which coordinate mainly to sulfate anions. EPR spectroscopy finally shows that divalent Mn{sup 2+} ions are present primarily in MnO{sub 6}-clusters, which, in the studied sulfophosphate glasses, convert upon increasing MnO content from corner-sharing to edge-sharing entities.

Bonding properties of FCC-like Au ₄₄ (SR) ₂₈ clusters from X-ray absorption spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Yang, Rui [Department of Chemistry, Dalhousie University, Halifax, NS B3H 4R2, Canada.; Chevrier, Daniel M. [Department of Chemistry, Dalhousie University, Halifax, NS B3H 4R2, Canada.; Zeng, Chenjie [Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA.; Jin, Rongchao [Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA.; Zhang, Peng [Department of Chemistry, Dalhousie University, Halifax, NS B3H 4R2, Canada.

2017-11-01

Thiolate-protected gold clusters with precisely controlled atomic composition have recently emerged as promising candidates for a variety of applications because of their unique optical, electronic, and catalytic properties. The recent discovery of the Au44(SR)28 total structure is considered as an interesting finding in terms of the face-centered cubic (FCC)-like core structure in small gold-thiolate clusters. Herein, the unique bonding properties of Au44(SR)28 is analyzed using temperature-dependent X-ray absorption spectroscopy (XAS) measurements at the Au L3-edge and compared with other FCC-like clusters such as Au36(SR)24 and Au28(SR)20. A negative thermal expansion was detected for the Au–Au bonds of the metal core (the first Au–Au shell) and was interpreted based on the unique Au core structure consisting of the Au4 units. EXAFS fitting results from Au28(SR)20, Au36(SR)24, and Au44(SR)28 show a size-dependent negative thermal expansion behavior in the first Au–Au shell, further highlighting the importance of the Au4 units in determining the Au core bonding properties and shedding light on the growth mechanism of these FCC-like Au clusters.

Diffusion-induced grain boundary migration during ion beam mixing of Au/Cu bilayers

International Nuclear Information System (INIS)

Alexander, D.E.; Baldo, P.M.; Rehn, L.E.

1992-09-01

Experiments were performed to evaluate the effect of 1.5 MeV Kr irradiation on diffusion-induced grain boundary migration (DIGM) in Au/Cu bilayers in the temperature range of 300≤T≤050K. The experimental results were consistent with DIGM occurring in bilayers both during irradiation and during annealing treatments. Rutherford backscattering spectrometry showed a nearly uniform distribution of Cu present through the entire thickness of appropriately prepared polycrystalline Au films irradiated or annealed at temperatures ≥400K. No parallel effect was seen in similarly treated single-crystal films. In each polycrystalline sample studied, irradiation resulted in greater amounts of Cu present uniformly in the Au compared to annealing-only. The magnitudes of measured Cu compositions were substantially greater than that expected solely from grain boundary diffusion. A simple analysis of the process indicated that ion irradiation affects DIGM by increasing the composition of Cu present in alloyed zones and/or by increasing the grain boundary velocity in the Au

Hydrothermal synthesis of coral-like Au/ZnO catalyst and photocatalytic degradation of Orange II dye

International Nuclear Information System (INIS)

Chen, P.K.; Lee, G.J.; Davies, S.H.; Masten, S.J.; Amutha, R.; Wu, J.J.

2013-01-01

Highlights: ► Coral-like Au/ZnO was successfully prepared using green synthetic method. ► Gold nanoparticles were deposited on the ZnO structure using NaBH 4 and β-D-glucose. ► Coral-like Au/ZnO exhibited superior photocatalytic activity to degrade Orange II. - Abstract: A porous coral-like zinc oxide (c-ZnO) photocatalyst was synthesized by the hydrothermal method. The coral-like structure was obtained by precipitating Zn 4 (CO 3 )(OH) 6 ·H 2 O (ZnCH), which forms nanosheets that aggregate together to form microspheres with the coral-like structure. X-ray diffraction (XRD) studies indicate that after heating at 550 °C the ZnCH microspheres can be converted to ZnO microspheres with a morphology similar to that of ZnCH microspheres. Thermogravimetric analysis (TGA) shows this conversion takes place at approximately 260 °C. A simple electrostatic self-assembly method has been employed to uniformly disperse Au nanoparticles (1 wt.%) on the ZnO surface. In this procedure β-D-glucose was used to stabilize the Au nanoparticles. Scanning electron microscope images indicate that the diameter of coral-like ZnO microspheres (c-ZnO) is about 8 μm. X-ray diffraction reveals that the ZnO is highly crystalline with a wurtzite structure and the Au metallic particles have an average size of about 13 nm. X-ray photoelectron spectroscopic (XPS) studies have confirmed the presence of ZnO and also showed that the Au is present in the metallic state. The photocatalytic degradation of Orange II dye, with either ultraviolet or visible light, is faster on Au/c-ZnO than on c-ZnO

Ion beam synthesis of Fe nanoparticles in MgO and yttria-stabilized zirconia

Science.gov (United States)

Potzger, K.; Reuther, H.; Zhou, Shengqiang; Mücklich, A.; Grötzschel, R.; Eichhorn, F.; Liedke, M. O.; Fassbender, J.; Lichte, H.; Lenk, A.

2006-04-01

To form embedded Fe nanoparticles, MgO(001) and YSZ(001) single crystals have been implanted at elevated temperatures with Fe ions at energies of 100 keV and 110 keV, respectively. The ion fluence was fixed at 6×1016 cm-2. As a result, γ- and α-phase Fe nanoparticles were synthesized inside MgO and YSZ, respectively. A synthesis efficiency of 100% has been achieved for implantation at 1273 K into YSZ. The ferromagnetic behavior of the α-Fe nanoparticles is reflected by a magnetic hyperfine field of 330 kOe and a hysteretic magnetization reversal. Electron holography showed a fringing magnetic field around some, but not all of the particles.

Ion beam synthesis of Fe nanoparticles in MgO and yttria-stabilized zirconia

International Nuclear Information System (INIS)

Potzger, K.; Reuther, H.; Zhou, Shengqiang; Muecklich, A.; Groetzschel, R.; Eichhorn, F.; Liedke, M. O.; Fassbender, J.; Lichte, H.; Lenk, A.

2006-01-01

To form embedded Fe nanoparticles, MgO(001) and YSZ(001) single crystals have been implanted at elevated temperatures with Fe ions at energies of 100 keV and 110 keV, respectively. The ion fluence was fixed at 6x10 16 cm -2 . As a result, γ- and α-phase Fe nanoparticles were synthesized inside MgO and YSZ, respectively. A synthesis efficiency of 100% has been achieved for implantation at 1273 K into YSZ. The ferromagnetic behavior of the α-Fe nanoparticles is reflected by a magnetic hyperfine field of 330 kOe and a hysteretic magnetization reversal. Electron holography showed a fringing magnetic field around some, but not all of the particles

Single-crystalline LiFePO4 nanosheets for high-rate Li-ion batteries.

Science.gov (United States)

Zhao, Yu; Peng, Lele; Liu, Borui; Yu, Guihua

2014-05-14

The lithiation/delithiation in LiFePO4 is highly anisotropic with lithium-ion diffusion being mainly confined to channels along the b-axis. Controlling the orientation of LiFePO4 crystals therefore plays an important role for efficient mass transport within this material. We report here the preparation of single crystalline LiFePO4 nanosheets with a large percentage of highly oriented {010} facets, which provide the highest pore density for lithium-ion insertion/extraction. The LiFePO4 nanosheets show a high specific capacity at low charge/discharge rates and retain significant capacities at high C-rates, which may benefit the development of lithium batteries with both favorable energy and power density.

Simultaneous study of sputtering and secondary ion emission of binary Fe-based alloys

International Nuclear Information System (INIS)

Riadel, M.M.; Nenadovic, T.; Perovic, B.

1976-01-01

The sputtering and secondary ion emission of binary Fe-based alloys of simple phase diagrams have been studied simultaneously. A series FeNi and FeCr alloys in the concentration range of 0-100% have been bombarded by 4 keV Kr + ions in a secondary ion mass spectrometer. The composition of the secondary ions has been analysed and also a fraction of the sputtered material has been collected and analysed by electron microprobe. The surface topography of the etched samples has been studied by scanning electron microscope. The relative sputtering coefficients of the metals have been determined, and the preferential sputtering of the alloying component of lower S have been proved. The etching pictures of samples are in correlation with the sputtering rates. Also the degree of secondary ionization has been calculated from the simultaneously measured ion emission and sputtering data. α + shows the change in the concentration range of the melting point minimum. This fact emphasizes the connection between the physico-chemical properties of alloys and their secondary emission process. From the dependence of the emitted homo- and hetero-cluster ions, conclusions could be shown concerning the production mechanism of small metallic aggregates

Structure of ion-implanted ceramics

International Nuclear Information System (INIS)

Naramoto, Hiroshi

1983-01-01

The variation of structure of LiF, MgO, Al 2 O 3 and TiO 2 accompanying annealing after ion implantation is explained. The analysis of structure is usually made by the perturbed gamma ray angular correlation, the internal electron Moessbauer method, or the ion scattering method. The results of analyses are discussed for alkali ion implantation, Fe-ion implantation, In-ion implantation, Au-ion implantation, Pt-ion implantation, Pb-ion implantation and transition metal ion implantation. The coupling of the implanted elements with lattice defects and matrix elements, and the compatibility between deposited elements and matrix crystal lattice were studied. The variation of physical properties due to ion implantation such as phase transition, volume change, the control of single crystal region, and the variation of hardness near surface were investigated, and the examples are presented. (Kato, T.)

Energy Dependence of Directed Flow over a Wide Range of Pseudorapidity in Au+Au Collisions at the BNL Relativistic Heavy Ion Collider

Science.gov (United States)

Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Hauer, M.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Seals, H.; Sedykh, I.; Skulski, W.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Wenger, E.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

2006-07-01

We report on measurements of directed flow as a function of pseudorapidity in Au+Au collisions at energies of sNN=19.6, 62.4, 130 and 200 GeV as measured by the PHOBOS detector at the BNL Relativistic Heavy Ion Collider. These results are particularly valuable because of the extensive, continuous pseudorapidity coverage of the PHOBOS detector. There is no significant indication of structure near midrapidity and the data surprisingly exhibit extended longitudinal scaling similar to that seen for elliptic flow and charged particle pseudorapidity density.

Sorption and reduction of selenite on chlorite surfaces in the presence of Fe(II) ions.

Science.gov (United States)

Baik, Min Hoon; Lee, Seung Yeop; Jeong, Jongtae

2013-12-01

The sorption and reduction of selenite on chlorite surfaces in the presence of Fe(II) ions were investigated as a function of pH, Se(IV) concentration, and Fe(II) concentration under an anoxic condition. The sorption of Se(IV) onto chlorite surfaces followed the Langmuir isotherm regardless of the presence of Fe(II) ions in the solution. The Se(IV) sorption was observed to be very low at all pH values when the solution was Fe(II)-free or the concentration of Fe(II) ions was as low as 0.5 mg/L. However, the Se(IV) sorption was enhanced at a pH > 6.5 when the Fe(II) concentration was higher than 5 mg/L because of the increased sorption of Fe(II) onto the chlorite surfaces. XANES (X-ray absorption near edge structure) spectra of the Se K-edge showed that most of the sorbed Se(IV) was reduced to Se(0) by Fe(II) sorbed onto the chlorite surfaces, especially at pH > 9. The combined results of field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) also showed that elemental selenium and goethite were formed and precipitated on the chlorite surfaces during the sorption of selenite. Consequently it can be concluded that Se(IV) can be reduced to Se(0) in the presence of Fe(II) ions by the surface catalytic oxidation of Fe(II) into Fe(III) and the formation of goethite at neutral and particularly alkaline conditions. Thus the mobility of selenite in groundwater is expected to be reduced by the presence of a relatively higher concentration of Fe(II) in subsurface environments. Copyright © 2013 Elsevier Ltd. All rights reserved.

Moessbauer-spectroscopic study of structure and magnetism of the exchange-coupled layer systems Fe/FeSn{sub 2}, and Fe/FeSi/Si and the ion-implanted diluted magnetic semiconductor SiC(Fe); Moessbauerspektroskopische Untersuchung von Struktur und Magnetismus der austauschgekoppelten Schichtsysteme Fe/FeSn{sub 2} und Fe/FeSi/Si und des ionenimplantierten verduennten magnetischen Halbleiters SiC(Fe)

Energy Technology Data Exchange (ETDEWEB)

Stromberg, Frank

2009-07-07

In line with this work the structural and magnetic properties of the exchange coupled layered systems Fe/FeSn{sub 2} and Fe/FeSi/Si and of the Fe ion implanted diluted magnetic semiconductor (DMS) SiC(Fe) were investigated. The main measuring method was the isotope selective {sup 57}Fe conversion electron Moessbauer spectroscopy (CEMS), mostly in connection with the {sup 57}Fe tracer layer technique, in a temperature range from 4.2 K to 340 K. Further measurement techniques were X-ray diffraction (XRD), electron diffraction (LEED, RHEED), SQUID magnetometry and FMR (Ferromagnetic Resonance). In the first part of this work the properties of thin AF FeSn{sub 2}(001) films and of the exchange-bias system Fe/FeSn{sub 2}(001) on InSb(001) were investigated. With the application of {sup 57}Fe-tracer layers and CEMS both the Fe-spin structure and the temperature dependence of the magnetic hyperfine field (B{sub hf}) of FeSn{sub 2} could be examined. The evaporation of Fe films on the FeSn{sub 2} films produced in the latter ones a high perpendicular spin component at the Fe/FeSn{sub 2} interface. In some distance from the interface the Fe spins rotate back into the sample plane. Furthermore {sup 57}Fe-CEMS provided a correlation between the absolute value of the exchange field vertical stroke He vertical stroke and the amount of magnetic defects within the FeSn{sub 2}. Temperature dependent CEMS-measurements yielded informations about the spin dynamics within the AF. The transition temperatures T{sub B}{sup *}, which were interpreted as superparamagnetic blocking temperatures, obtain higher values compared to the temperatures T{sub B} of the exchange-bias effect, obtained with magnetometry measurements. The second part of this work deals with the indirect exchange coupling within Fe/FeSi/Si/FeSi/Fe multilayers and FeSi diffusion barriers. The goal was to achieve Fe free Si interlayers. The CEMS results show that starting from a thickness of t{sub FeSi}=10-12 A of the

Thermal Characteristics of Conversion-Type FeOF Cathode in Li-ion Batteries

Directory of Open Access Journals (Sweden)

Liwei Zhao

2017-10-01

Full Text Available Rutile FeOF was used as a conversion-type cathode material for Li-ion batteries. In the present study, 0.6Li, 1.4Li, and 2.7Li per mole lithiation reactions were carried out by changing the electrochemical discharge reaction depth. The thermal characteristics of the FeOF cathode were investigated by thermogravimetric mass spectrometric (TG-MS and differential scanning calorimeter (DSC systems. No remarkable HF release was detected, even up to 700 °C, which indicated a low toxic risk for the FeOF cathode. Changes in the thermal properties of the FeOF cathode via different conversion reaction depths in the associated electrolyte were studied by changing the cathode/electrolyte ratio in the mixture. LiFeOF was found to exothermically react with the electrolyte at about 210 °C. Similar exothermic reactions were found with charged FeOF cathodes because of the irreversible Li ions. Among the products of the conversion reaction of FeOF, Li2O was found to exothermically react with the electrolyte at about 120 °C, which induced the main thermal risk of the FeOF cathode. It suggests that the oxygen-containing conversion-type cathodes have a higher thermal risk than the oxygen-free ones, but controlling the cathode/electrolyte ratio in cells successfully reduced the thermal risk. Finally, the thermal stability of the FeOF cathode was evaluated in comparison with FeF3 and LiFePO4 cathodes.

Potential use of SERS-assisted theranostic strategy based on Fe{sub 3}O{sub 4}/Au cluster/shell nanocomposites for bio-detection, MRI, and magnetic hyperthermia

Energy Technology Data Exchange (ETDEWEB)

Han, Yu; Lei, Sheng-lan [Department of Biomaterials, College of Materials, Xiamen University, Xiamen 361005 (China); Lu, Jian-hua [Department of Electronic Science, College of Physical Science and Technology, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance Research, Xiamen University, Xiamen 361005 (China); He, Yuan [Department of Biomaterials, College of Materials, Xiamen University, Xiamen 361005 (China); Chen, Zhi-wei, E-mail: chenzhiwei@xmu.edu.cn [Department of Electronic Science, College of Physical Science and Technology, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance Research, Xiamen University, Xiamen 361005 (China); Ren, Lei, E-mail: renlei@xmu.edu.cn [Department of Biomaterials, College of Materials, Xiamen University, Xiamen 361005 (China); State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005 (China); Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen 361005 (China); Zhou, Xi [Department of Biomaterials, College of Materials, Xiamen University, Xiamen 361005 (China); Fujian Provincial Key Laboratory of Fire Retardant Materials, Xiamen University, Xiamen 361005 (China); Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen 361005 (China)

2016-07-01

A surface-enhanced Raman scattering (SERS)-assisted theranostic strategy was designed based on a synthesized multifunctional Fe{sub 3}O{sub 4}/Au cluster/shell nanocomposite. This theranostic strategy was used for free prostate specific antigen (free-PSA) detection, magnetic resonance imaging (MRI), and magnetic hyperthermia. The lowest protein concentration detected was 1 ng mL{sup −1}, and the limit of detection (LOD) of the calculated PSA was 0.75 ng mL{sup −1}. Then, MRI was carried out to visualize the tumor cell. Lastly, magnetic hyperthermia was employed and revealed a favorable killing effect for the tumor cells. Thus, this SERS-assisted strategy based on a Fe{sub 3}O{sub 4}/Au cluster/shell nanocomposite showed great advantages in theranostic treatment. - Graphical abstract: Fe{sub 3}O{sub 4}/Au cluster/shell composite can be used for specific protein detection, magnetic resonance imaging and magnetic hyperthermia therapy. - Highlights: • We designed a SERS-assisted theranostic strategy based on the mutifunctional nanocomposites using gold shelled Fe{sub 3}O{sub 4} clusters. • Fe{sub 3}O{sub 4}/Au nanoparticles with theranostics and SERS for early diagnosis of PSA were reported for the first time. • The LOD of detection for PSA was lowed as 0.75 ng mL{sup −1}, and the total detection time was shorten to less than 1 h. • Fe{sub 3}O{sub 4} clusters had spin-spin (T{sub 2}) contrast enhancement and increased magnetic response. • Gold nanoshells supplied excellent chemical stability, biocompatibility, better heating property for magnetic hyperthermia.

Differential effects of x-rays and high-energy 56Fe ions on human mesenchymal stem cells.

Science.gov (United States)

Kurpinski, Kyle; Jang, Deok-Jin; Bhattacharya, Sanchita; Rydberg, Bjorn; Chu, Julia; So, Joanna; Wyrobek, Andy; Li, Song; Wang, Daojing

2009-03-01

Stem cells hold great potential for regenerative medicine, but they have also been implicated in cancer and aging. How different kinds of ionizing radiation affect stem cell biology remains unexplored. This study was designed to compare the biological effects of X-rays and of high-linear energy transfer (LET) (56)Fe ions on human mesenchymal stem cells (hMSC). A multi-functional comparison was carried out to investigate the differential effects of X-rays and (56)Fe ions on hMSC. The end points included modulation of key markers such as p53, cell cycle progression, osteogenic differentiation, and pathway and networks through transcriptomic profiling and bioinformatics analysis. X-rays and (56)Fe ions differentially inhibited the cell cycle progression of hMSC in a p53-dependent manner without impairing their in vitro osteogenic differentiation process. Pathway and network analyses revealed that cytoskeleton and receptor signaling were uniquely enriched for low-dose (0.1 Gy) X-rays. In contrast, DNA/RNA metabolism and cell cycle regulation were enriched for high-dose (1 Gy) X-rays and (56)Fe ions, with more significant effects from (56)Fe ions. Specifically, DNA replication, DNA strand elongation, and DNA binding/transferase activity were perturbed more severely by 1 Gy (56)Fe ions than by 1 Gy X-rays, consistent with the significant G2/M arrest for the former while not for the latter. (56)Fe ions exert more significant effects on hMSC than X-rays. Since hMSC are the progenitors of osteoblasts in vivo, this study provides new mechanistic understandings of the relative health risks associated with low- and high-dose X-rays and high-LET space radiation.

Report of TOF for 900 MeV/n Au ions

Energy Technology Data Exchange (ETDEWEB)

Crawford, H J; Flores, I; Lindstrom, P J; Krebs, G

1986-04-15

We describe a measurement of the time of flight over an 18.5 m path of 900 MeV/n Au ions from the LBL Bevalac. We used two small scintillators viewed by XP2972 photomultiplier tubes without any light guides. The large light output allowed us to attain a resolution of 58 ps in the flight time and an energy resolution of 3 MeV/n. The system is being used in energy loss and machine performance studies.

Au nanoparticles grafted on Fe{sub 3}O{sub 4} as effective SERS substrates for label-free detection of the 16 EPA priority polycyclic aromatic hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Du, Jingjing; Xu, Jianwei; Sun, Zhenli; Jing, Chuanyong, E-mail: cyjing@rcees.ac.cn

2016-04-07

Several methods and materials have been explored for the sensitive and practicable detection of polycyclic aromatic hydrocarbons (PAHs). However, it is still a challenge to develop simple and cost-effective sensing techniques for PAHs. Herein we report the synthesis and construction of Fe{sub 3}O{sub 4}@Au SERS substrate. This magnetic substrate was composed by Fe{sub 3}O{sub 4} microspheres and Au NPs. The size, morphology, and surface composition of Fe{sub 3}O{sub 4}@Au were characterized by multiple complimentary techniques including scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray powder diffraction. The spatial distributions of electro-magnetic field enhancement around Fe{sub 3}O{sub 4}@Au was calculated using finite difference time domain (FDTD) simulations. As a result of its remarkable sensitivity, the Fe{sub 3}O{sub 4}@Au-based SERS assay has been applied to detect the 16 EPA priority PAHs. The LODs achieved by our method (100–5 nM, 16.6–1.01 μg L{sup −1}) make it promising for the rapid screening of highly contaminated cases. As a proof-of-concept study, the substrate was applied in SERS sensing of PAHs in river matrix. The 16 PAHs could be differentiated based upon their characteristic SERS peaks. Most importantly, the detection was successfully conducted using a portable Raman spectrometer, which could be used for on-site monitoring of PAHs. - Highlights: • SERS detection of the 16 EPA priority PAHs was conducted. • The satellite-core structure lead to high SERS enhancement by confined hotspots. • The approach does not require expensive instrumentation or large sample volumes. • The effective protocol is useful for the identification of hydrophobic molecules.

Rhodamine B immobilized on hollow Au-HMS material for naked-eye detection of Hg{sup 2+} in aqueous media

Energy Technology Data Exchange (ETDEWEB)

Zhang, Na [State Key Laboratory of Fine Chemicals, College of Chemical Engineering, Dalian University of Technology, Dalian, 116024 (China); Li, Gang, E-mail: liganghg@dlut.edu.cn [State Key Laboratory of Fine Chemicals, College of Chemical Engineering, Dalian University of Technology, Dalian, 116024 (China); Cheng, Zhuhong [State Key Laboratory of Fine Chemicals, College of Chemical Engineering, Dalian University of Technology, Dalian, 116024 (China); Zuo, Xiujin [Key Laboratory of Bio-organic Chemistry, College of Environmental and Chemical Engineering, Dalian University, Dalian, 116622 (China)

2012-08-30

Graphical abstract: Au-HMS-Probe with worm-like mesoporous framework for detection of Hg{sup 2+} in aqueous media has been simply and effectively synthesized by immobilizing a Rhodamine B derivative on Au-HMS via Au-N groups under room temperature. Highlights: Black-Right-Pointing-Pointer Au-HMS-Probe is prepared via Au-N bonds. Black-Right-Pointing-Pointer Gold nanoparticles are chosen as connectors instead of silane agents. Black-Right-Pointing-Pointer Au-HMS is chosen as carrier for the first time. Black-Right-Pointing-Pointer The immobilization method of Au-HMS-Probe is very simple and effective. Black-Right-Pointing-Pointer Au-HMS-Probe shows excellent ability for detecting Hg{sup 2+} by naked-eye. - Abstract: A simple, effective method has been demonstrated to immobilize Rhodamine B (RhB) probes on mesoporous silica (Au-HMS). The prepared chemosensor (Au-HMS-Probe) was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), UV-vis spectrum and Fourier transform infrared spectroscopy (FT-IR). Further application of Au-HMS-Probe in sensing Hg{sup 2+} was confirmed by fluorescence titration experiment. Au-HMS-Probe afforded 'turn-on' fluorescence enhancement and displayed high brightness in water, and it also showed excellent selectivity for Hg{sup 2+} over alkali (Na{sup +}, K{sup +}), alkaline earth (Mg{sup 2+}, Ca{sup 2+}) and other heavy metal ions (Ag{sup +}, Cd{sup 2+}, Co{sup 2+}, Pb{sup 2+}, Ni{sup 2+}, Cu{sup 2+}, Fe{sup 2+}). Importantly, Au-HMS-Probe could be regenerated by treatment with tetrapropylammonium hydroxide solution.

SEPARATION OF Fe (III, Cr(III, Cu(II, Ni(II, Co(II, AND Pb(II METAL IONS USING POLY(EUGENYL OXYACETIC ACID AS AN ION CARRIER BY A LIQUID MEMBRANE TRANSPORT METHOD

Directory of Open Access Journals (Sweden)

La Harimu

2010-06-01

Full Text Available Fe (III, Cr(III, Cu(II, Ni(II, Co(II, and Pb(II  metal ions had been separated using poly(eugenyl oxyacetic acid as an ion carrier by bulk liquid membrane transport method. The effect of pH, polyeugenyl oxyacetic acid ion carrier concentration, nitric acid concentration in the stripping solution, transport time, and metal concentration were optimized. The result showed that the optimum condition for transport of metal ions was at pH 4 for ion Fe(III and at pH 5 for Cr(III, Cu(II, Ni(II, Co(II, and Pb(II ions. The carrier volumes were optimum with concentration of 1 x 10-3 M at 7.5 mL for Cr(III, Cu (II,  Ni(II, Co(II ions and at 8.5 mL for Fe(III and Pb(II ions. The concentration of HNO3 in stripping phase was optimum at 2 M for Fe(III and Cu(II ions, 1 M for Cr(III, Ni(II and Co(II ions, and 0.5 M for Pb(II ion. The optimum transport times were 36 h for Fe(III and Co(II ions, and 48 h for Cr(III, Cu (II, Ni(II, and Pb(II ions. The concentration of metal ions accurately transported were 2.5 x 10-4 M for Fe(III and Cr(III ions, and 1 M for Cu (II, Ni(II, Co(II, and Pb(II ions. Compared to other metal ions the transport of Fe(III was the highest with selectivity order of Fe(III > Cr(III > Pb(II > Cu(II > Ni(II > Co(II. At optimum condition, Fe(III ion was transported through the membrane at 46.46%.   Keywords: poly(eugenyl oxyacetic acid, transport, liquid membrane, Fe (III, Cr(III, Cu(II, Ni(II, Co(II, and Pb(II ions

Highly open bowl-like PtAuAg nanocages as robust electrocatalysts towards ethylene glycol oxidation

Science.gov (United States)

Xu, Hui; Yan, Bo; Li, Shumin; Wang, Jin; Song, Pingping; Wang, Caiqin; Guo, Jun; Du, Yukou

2018-04-01

A novel combined seed mediated and galvanic replacement method has been demonstrated to synthesize a new class of trimetallic PtAuAg nanocatalysts with highly open bowl-like nanocage structure. The newly-generated PtAuAg nanocages catalysts exhibit superior electrocatalytic performances towards ethylene glycol oxidation with the mass activity of 6357.1 mA mg-1, 5.5 times higher than that of commercial Pt/C (1151.1 mA mg-1). This work demonstrates the first example of designing shape-controlled architectures of trimetallic bowl-like PtAuAg nanocages for liquid fuel electrooxidation.

Influence of the surface topography, morphology and structure on magnetic properties of ion beam sputtered iron layers, Fe/Cr/Fe- and Fe/MgO/Fe multilayers; Untersuchung der Morphologie und magnetische Eigenschaften von ionenstrahl-gesputterten Eisen-Einzelschichten, Fe/Cr/Fe- und Fe/MgO/Fe-Schichtsystemen

Energy Technology Data Exchange (ETDEWEB)

Steeb, Alexandra

2007-04-05

In this PhD Thesis, the influence of the surface topography, morphology and structure on magnetic properties of ion beam sputtered iron layers on GaAs is examined. To analyze the structure of the produced iron films, low energy electron diffraction and scanning tunneling microscopy is employed. The utilized methods to investigate the magnetic properties are Kerr- and SQUID-magnetometry and ferromagnetic resonance. It is demonstrated that on untreated as well as on presputtered and heated GaAs substrates the sputtered iron films grow epitaxially. The least surface roughness of 1 A exhibit iron films grown on untreated GaAs, while iron films on heated GaAs have the highest roughness of 30 A. The largest crystal anisotropy constant is found for the presputtered GaAs/Fe-System. For this preparation method, two monolayers of iron are determined to be magnetically dead layers. At a film thickness of 100 A, 83% of the value for saturation magnetization of bulk iron are achieved. The small observed FMR-linewidths confirm the good bulk properties of the ion beam sputtered iron. Furthermore, an antiferromagnetic interlayer exchange coupling in sputtered Fe/Cr/Fe-films was achieved. For a thickness of 12 to 17 A of the chrome interlayer, a coupling strength up to 0.2 mJ/m{sup 2} is found. To account for the small coupling strength, a strong intermixing at the interface is assumed. Finally, epitaxial Fe/MgO/Fe/FeMn multilayers are deposited on GaAs. After the structuring, it is possible to detect tunneling processes in the tunneling contacts with current-voltage measurements. The tunnel magneto resistance values of 2% are small, which can be explained by the absence of sharp, well-defined interfaces between the Fe/FeMn and the Fe/MgO interfaces. These results demonstrate, that analog to MBE the ion beam sputtering method realizes good magnetic bulk properties. However, interface sensitive phenomena are weakened because of a strong intermixing at the interfaces. (orig.)

Facile synthesis of Fe4N/Fe2O3/Fe/porous N-doped carbon nanosheet as high-performance anode for lithium-ion batteries

Science.gov (United States)

Zhang, Dan; Li, Guangshe; Yu, Meijie; Fan, Jianming; Li, Baoyun; Li, Liping

2018-04-01

Iron nitrides are considered as highly promising anode materials for lithium-ion batteries because of their nontoxicity, high abundance, low cost, and higher electrical conductivity. Unfortunately, their limited synthesis routes are available and practical application is still hindered by their fast capacity decay. Herein, a facile and green route is developed to synthesize Fe4N/Fe2O3/Fe/porous N-doped carbon nanosheet composite. The size of Fe4N/Fe2O3/Fe particles is small (10-40 nm) and they are confined in porous N-doped carbon nanosheet. These features are conducive to accommodate volume change well, shorten the diffusion distance and further elevate electrical conductivity. When tested as anode material for lithium-ion batteries, a high discharge capacity of 554 mA h g-1 after 100 cycles at 100 mA g-1 and 389 mA h g-1 after 300 cycles at 1000 mA g-1 are retained. Even at 2000 mA g-1, a high capacity of 330 mA h g-1 can be achieved, demonstrating superior cycling stability and rate performance. New prospects will be brought by this work for the synthesis and the potential application of iron nitrides materials as an anode for LIBs.

One-pot synthesis of Fe{sub 3}O{sub 4}/Fe/MWCNT nanocomposites via electrical wire pulse for Li ion battery electrodes

Energy Technology Data Exchange (ETDEWEB)

Lee, Duk-Hee; Seo, Seung-Deok; Lee, Gwang-Hee [School of Civil, Environmental and Architectural Engineering, Korea University, 145, Anam-Ro, Seongbuk-Gu, Seoul 136-713 (Korea, Republic of); Hong, Hyun-Seon [Advanced Materials and Processing Center, Institute for Advanced Engineering, Yongin 449-863 (Korea, Republic of); Kim, Dong-Wan, E-mail: dwkim1@korea.ac.kr [School of Civil, Environmental and Architectural Engineering, Korea University, 145, Anam-Ro, Seongbuk-Gu, Seoul 136-713 (Korea, Republic of)

2014-09-01

Highlights: • Synthesis of Fe{sub 3}O{sub 4}/Fe/MWCNT nanocolloids using an electrical wire explosion process. • Electrical connection of Fe{sub 3}O{sub 4} to a current collector by the conducting networks. • Improved electrochemical performance of Fe{sub 3}O{sub 4}/Fe/MWCNT nanocomposite electrodes. - Abstract: Nanocomposites containing Fe{sub 3}O{sub 4}/Fe/multiwalled carbon nanotubes (MWCNT) were prepared via an electrical wire pulse process (a top-down approach) using Fe wire and dispersed, functionalized MWCNT in deionized water (DIW) at room temperature. The structural and electrochemical characteristics of the resulting nanocomposites were investigated in detail. When used as an anode for Li ion batteries, the Fe{sub 3}O{sub 4}/Fe/MWCNT nanocomposites exhibited greater cycle stability and rate performance than plain Fe{sub 3}O{sub 4}/Fe composites, with a capacity of 460 mA h g{sup −1} at a rate of 168 mA g{sup −1} after 50 cycles. The enhanced performance was attributed to superior electrical conductivity and buffering effect of the MWCNTs on volume changes of the anodes. This process is a promising facile method for lithium ion battery anode material synthesis.

Nano-jewellery: C5Au12--a gold-plated diamond at molecular level.

Science.gov (United States)

Naumkin, F

2006-06-07

A mixed carbon-metal cluster is designed by combining the tetrahedral C(5) radical (with a central atom-the skeleton of the C(5)H(12) molecule) and the spherical Au(12) layer (the external atomic shell of the Au(13) cluster). The C(5)Au(12) cluster and its negative and positive ionic derivatives, C(5)Au(12)(+/-), are investigated ab initio (DFT) in terms of optimized structures and relative energies of a few spin-states, for the icosahedral-like and octahedral-like isomers. The cluster is predicted to be generally more stable in its octahedral shape (similar to C(5)H(12)) which prevails for the negative ion and may compete with the icosahedral shape for the neutral system and positive ion. Adiabatic ionization energies (AIE) and electron affinities (AEA) of C(5)Au(12), vertical electron-detachment (VDE) energies of C(5)Au(12)(-), and vertical ionization and electron-attachment energies (VIE, VEA) of C(5)Au(12) are calculated as well, and compared with those for the corresponding isomers of the Au(13) cluster. The AIE and VIE values are found to be close for the two systems, while the AEA and VDE values are significantly reduced for the radical-based species. A simple fragment-based model is proposed for the decomposition of the total interaction into carbon-gold and gold-gold components.

Influence of nanostructure Fe-doped ZnO interlayer on the electrical properties of Au/n-type InP Schottky structure

Energy Technology Data Exchange (ETDEWEB)

Padma, R.; Balaram, N.; Reddy, I. Neelakanta; Reddy, V. Rajagopal, E-mail: reddy_vrg@rediffmail.com

2016-07-01

The Au/Fe-doped ZnO/n-InP metal/interlayer/semiconductor (MIS) Schottky structure is fabricated with Fe-doped ZnO nanostructure (NS) as an interlayer. The field emission scanning electron microscopy and atomic force microscopy results demonstrated that the surface morphology of the Fe−ZnO NS on n-InP is fairly smooth. The x-ray diffraction results reveal that the average grain size of the Fe−ZnO film is 12.35 nm. The electrical properties of the Au/n-InP metal-semiconductor (MS) and Au/Fe−ZnO NS/n-InP MIS Schottky structures are investigated by current-voltage and capacitance-voltage measurements at room temperature. The Au/Fe−ZnO NS/n-InP MIS Schottky structure has good rectifying ratio with low-leakage current compared to the Au/n-InP MS structure. The barrier height obtained for the MIS structure is higher than those of MS Schottky structure because of the modification of the effective barrier height by the Fe−ZnO NS interlayer. Further, the barrier height, ideality factor and series resistance are determined for the MS and MIS Schottky structures using Norde and Cheung's functions and compared to each other. The estimated interface state density of MIS Schottky structure is lower than that of MS Schottky structure. Experimental results revealed that the Poole-Frenkel emission is the dominant conduction mechanism in the lower bias region whereas Schottky emission is the dominant in the higher bias region for both the Au/n-InP MS and Au/Fe−ZnO NS/n-InP MIS Schottky structures. - Highlights: • Barrier height of Au/n-InP Schottky diode was modified by Fe−ZnO nanostructure interlayer. • MIS structure has a good rectification ratio compared to the MS structure. • The interface state density of MIS structure is lower than that of MS structure. • Poole-Frenkel mechanism is found to dominate in both MS and MIS structure.

Moessbauer studies of 57Fe substitution of Cu ions in superconducting oxides

International Nuclear Information System (INIS)

Saitovitch, E.B.

1988-01-01

Since the discovery of high-T c superconductivity in YBa 2 Cu 3 O 7 oxides several studies of metal ions substitutions were reported. The observed depression on T c without a systematic correlation with the charge and magnetic moment of Cu substituents claims for more detailed information about its local properties as can be revealed by 57 Fe Moessbauer spectroscopy. The results for different iron concentrations combined with modifications of the superconducting transition are discussed concerning the presence of magnetic moments on the Fe ions and the preferential occupation of Cu(1) sites, recently confirmed by neutron and electron diffraction experiments. The oxygen coordination for the different iron species are proposed on the basis of their dependence on Fe concentration, their behavior at high temperatures as well as the electron diffraction and electron microscopy measurements reported for Fe: YBa 2 Cu 3 O 7 samples. (author) [pt

130 MeV Au ion irradiation induced dewetting on In{sub 2}Te{sub 3} thin film

Energy Technology Data Exchange (ETDEWEB)

Matheswaran, P.; Abhirami, K.M.; Gokul, B. [Department of Physics, Kongunadu Arts and Science College, Coimbatore 641029 (India); Sathyamoorthy, R., E-mail: rsathya1959@gmail.com [Department of Physics, Kongunadu Arts and Science College, Coimbatore 641029 (India); Prakash, Jai [Department of Chemistry, M.M.H. College, Ghaziabad 201001 (India); Asokan, K.; Kanjilal, D. [Materials Science Division, Inter University Accelerator Centre, New Delhi 110067 (India)

2012-09-01

Highlights: Black-Right-Pointing-Pointer In{sub 2}Te{sub 3} phase formed from In/Te bilayer by 130 MeV Au ion irradiation. Black-Right-Pointing-Pointer Lower fluence results mixed phases with initial state of dewetting. Black-Right-Pointing-Pointer At higher fluence, In{sub 2}Te{sub 3} phase with complete dewetting pattern is formed. Black-Right-Pointing-Pointer Thermal spike model is used to explain the inter face mixing phenomena. Black-Right-Pointing-Pointer SHI irradiation may be used to functionalize the structural and surface properties of thin films. - Abstract: In/Te bilayer thin films were prepared by sequential thermal evaporation and subsequently irradiated by 130 MeV Au ions. The pristine and irradiated samples were characterized by X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) techniques. RBS spectra reveal the sputtering of Te film and interface mixing, with increasing fluence. The surface morphology showed the beginning of dewetting of Te thin film and formation of the partially connected with the mixed zones at the fluence of 1 Multiplication-Sign 10{sup 13} ions/cm{sup 2}. At the higher fluence of 3 Multiplication-Sign 10{sup 13} ions/cm{sup 2}, dewetted structures were isolated at the surface. Above results are explained based on the formation of craters, sputtering and dewetting followed by inter-diffusion at the interface of molten zones due to thermal spike induced by Au ions.

Differential Effects of X-Rays and High-Energy 56Fe Ions on Human Mesenchymal Stem Cells

International Nuclear Information System (INIS)

Kurpinski, Kyle; Jang, Deok-Jin; Bhattacharya, Sanchita; Rydberg, Bjorn; Chu, Julia; So, Joanna; Wyrobek, Andy; Li Song; Wang Daojing

2009-01-01

Purpose: Stem cells hold great potential for regenerative medicine, but they have also been implicated in cancer and aging. How different kinds of ionizing radiation affect stem cell biology remains unexplored. This study was designed to compare the biological effects of X-rays and of high-linear energy transfer (LET) 56 Fe ions on human mesenchymal stem cells (hMSC). Methods and Materials: A multi-functional comparison was carried out to investigate the differential effects of X-rays and 56 Fe ions on hMSC. The end points included modulation of key markers such as p53, cell cycle progression, osteogenic differentiation, and pathway and networks through transcriptomic profiling and bioinformatics analysis. Results: X-rays and 56 Fe ions differentially inhibited the cell cycle progression of hMSC in a p53-dependent manner without impairing their in vitro osteogenic differentiation process. Pathway and network analyses revealed that cytoskeleton and receptor signaling were uniquely enriched for low-dose (0.1 Gy) X-rays. In contrast, DNA/RNA metabolism and cell cycle regulation were enriched for high-dose (1 Gy) X-rays and 56 Fe ions, with more significant effects from 56 Fe ions. Specifically, DNA replication, DNA strand elongation, and DNA binding/transferase activity were perturbed more severely by 1 Gy 56 Fe ions than by 1 Gy X-rays, consistent with the significant G2/M arrest for the former while not for the latter. Conclusions: 56 Fe ions exert more significant effects on hMSC than X-rays. Since hMSC are the progenitors of osteoblasts in vivo, this study provides new mechanistic understandings of the relative health risks associated with low- and high-dose X-rays and high-LET space radiation

Report of TOF for 900 MeV/n Au ions

International Nuclear Information System (INIS)

Crawford, H.J.; Flores, I.; Lindstrom, P.J.; Krebs, G.

1986-01-01

We describe a measurement of the time of flight over an 18.5 m path of 900 MeV/n Au ions from the LBL Bevalac. We used two small scintillators viewed by XP2972 photomultiplier tubes without any light guides. The large light output allowed us to attain a resolution of 58 ps in the flight time and an energy resolution of 3 MeV/n. The system is being used in energy loss and machine performance studies. (orig.)

Report of TOF for 900 MeV/n Au ions

Energy Technology Data Exchange (ETDEWEB)

Crawford, H J; Flores, I; Lindstrom, P J; Krebs, G

1986-04-15

We describe a measurement of the time of flight over an 18.5 m path of 900 MeV/n Au ions from the LBL Bevalac. We used two small scintillators viewed by XP2972 photomultiplier tubes without any light guides. The large light output allowed us to attain a resolution of 58 ps in the flight time and an energy resolution of 3 MeV/n. The system is being used in energy loss and machine performance studies. (orig.).

Growth and morphological analysis of segmented AuAg alloy nanowires created by pulsed electrodeposition in ion-track etched membranes

Directory of Open Access Journals (Sweden)

Ina Schubert

2015-06-01

Full Text Available Background: Multicomponent heterostructure nanowires and nanogaps are of great interest for applications in sensorics. Pulsed electrodeposition in ion-track etched polymer templates is a suitable method to synthesise segmented nanowires with segments consisting of two different types of materials. For a well-controlled synthesis process, detailed analysis of the deposition parameters and the size-distribution of the segmented wires is crucial.Results: The fabrication of electrodeposited AuAg alloy nanowires and segmented Au-rich/Ag-rich/Au-rich nanowires with controlled composition and segment length in ion-track etched polymer templates was developed. Detailed analysis by cyclic voltammetry in ion-track membranes, energy-dispersive X-ray spectroscopy and scanning electron microscopy was performed to determine the dependency between the chosen potential and the segment composition. Additionally, we have dissolved the middle Ag-rich segments in order to create small nanogaps with controlled gap sizes. Annealing of the created structures allows us to influence their morphology.Conclusion: AuAg alloy nanowires, segmented wires and nanogaps with controlled composition and size can be synthesised by electrodeposition in membranes, and are ideal model systems for investigation of surface plasmons.

LiFePO4 mesocrystals for lithium-ion batteries.

Science.gov (United States)

Popovic, Jelena; Demir-Cakan, Rezan; Tornow, Julian; Morcrette, Mathieu; Su, Dang Sheng; Schlögl, Robert; Antonietti, Markus; Titirici, Maria-Magdalena

2011-04-18

Olivine LiFePO(4) is considered one of the most promising cathode materials for Li-ion batteries. A simple one-step, template-free, low-temperature solvothermal method is developed for the synthesis of urchinlike hierarchical mesocrystals of pristine LiFePO(4) as well as carbon-coated LiFePO(4) composites. Each urchinlike mesocrystal consists of LiFePO(4) sheets self-assembled via a dipolar field in spheres during a solvothermal process under the influence of Cl(-) anions. The obtained primary sheets of LiFePO(4) are single crystalline in nature and can be coated in situ with an amorphous nitrogen-doped carbonaceous layer several nanometers in thickness. To increase the conductivity of the carbon coating, the materials are subjected to further temperature treatment (700 °C) under an inert atmosphere. The lithium storage performance of the pure LiFePO(4) is compared with that of its carbon-coated counterparts. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fission from Fe and Nb reactions with heavy targets at 50--100 MeV/nucleon

International Nuclear Information System (INIS)

Begemann-Blaich, M.; Blaich, T.; Fowler, M.M.; Wilhelmy, J.B.; Britt, H.C.; Fields, D.J.; Hansen, L.F.; Lanier, R.G.; Massoletti, D.J.; Namboodiri, M.N.; Remington, B.A.; Sangster, T.C.; Struble, G.L.; Webb, M.L.; Chan, Y.D.; Dacal, A.; Harmon, A.; Pouliot, J.; Stokstad, R.G.; Kaufman, S.; Videbaek, F.; Fraenkel, Z.

1992-01-01

Cross sections, parallel and perpendicular momentum transfers, charge loss, and velocity systematics are presented for fission following reactions of Fe and Nb projectiles at 50--100 MeV/nucleon on targets of Ta, Au, and Th. Data are compared to simple models for peripheral heavy ion collisions

Ion irradiation effects on high purity bcc Fe and model FeCr alloys

International Nuclear Information System (INIS)

Bhattacharya, Arunodaya

2014-01-01

FeCr binary alloys are a simple representative of the reduced activation ferritic/martensitic (F-M) steels, which are currently the most promising candidates as structural materials for the sodium cooled fast reactors (SFR) and future fusion systems. However, the impact of Cr on the evolution of the irradiated microstructure in these materials is not well understood in these materials. Moreover, particularly for fusion applications, the radiation damage scenario is expected to be complicated further by the presence of large quantities of He produced by the nuclear transmutation (∼ 10 appm He/dpa). Within this context, an elaborate ion irradiation study was performed at 500 C on a wide variety of high purity FeCr alloys (with Cr content ranging from ∼ 3 wt.% to 14 wt.%) and a bcc Fe, to probe in detail the influence of Cr and He on the evolution of microstructure. The irradiations were performed using Fe self-ions, in single beam mode and in dual beam mode (damage by Fe ions and co-implantation of He), to separate ballistic damage effect from the impact of simultaneous He injection. Three different dose ranges were studied: high dose (157 dpa, 17 appm He/dpa for the dual beam case), intermediate dose (45 dpa, 57 appm He/dpa for dual beam case) and in-situ low dose (0.33 dpa, 3030 appm He/dpa for the dual beam case). The experiments were performed at the JANNuS triple beam facility and dual beam in situ irradiation facility at CEA-Saclay and CSNSM, Orsay respectively. The microstructure was principally characterized by conventional TEM, APT and EDS in STEM mode. The main results are as follows: 1) A comparison of the cavity microstructure in high dose irradiated Fe revealed strong swelling reduction by the addition of He. It was achieved by a drastic reduction in cavity sizes and an increased number density. This behaviour was observed all along the damage depth, up to the damage peak. 2) Cavity microstructure was also studied in the dual beam high dose

Ultra-small Fe3O4 nanocrystals decorated on 2D graphene nanosheets with excellent cycling stability as anode materials for lithium ion batteries

International Nuclear Information System (INIS)

Ren, Manman; Yang, Mingzhi; Liu, Weiliang; Li, Mei; Su, Liwei; Qiao, Congde; Wu, Xianbin; Ma, Houyi

2016-01-01

Graphical abstract: Ultra-small Fe 3 O 4 nanocrystals decorated on 2D graphene nanosheets with excellent cycling stability as anode materials for lithium ion batteries Manman Ren, Mingzhi Yang, Weiliang Liu, Mei Li, Liwei Su, Congde Qiao, Xianbin Wu, Houyi Ma Ultra-small Fe 3 O 4 nanocrystals/graphene nanosheets composites demonstrate excellent long-term cycling stability at high-rate. - Abstract: Ultra-small Fe 3 O 4 nanocrystals (NCs)/garphene nanosheets (GNSs) composites have been synthesized through a facile gel-like film (GF) assisted method in this work. Fe 3 O 4 NCs with particle size ∼10 nm homogeneously dispersed on 2D GNSs. Profiting from the ultra-small Fe 3 O 4 NCs and GNSs, the composites demonstrate superior long-term and high-rate performance as anode materials for lithium ion batteries. Even at the current density of 5 A g −1 , the reversible capacity still maintains 323.4 mAh g −1 after 700 cycles. This work might enlighten us on exploring preferable strategies to develop advanced metal oxides NCs/GNSs composites anode materials for lithium ion batteries or other energy storage devices.

The formation of magnetic silicide Fe3Si clusters during ion implantation

Science.gov (United States)

Balakirev, N.; Zhikharev, V.; Gumarov, G.

2014-05-01

A simple two-dimensional model of the formation of magnetic silicide Fe3Si clusters during high-dose Fe ion implantation into silicon has been proposed and the cluster growth process has been computer simulated. The model takes into account the interaction between the cluster magnetization and magnetic moments of Fe atoms random walking in the implanted layer. If the clusters are formed in the presence of the external magnetic field parallel to the implanted layer, the model predicts the elongation of the growing cluster in the field direction. It has been proposed that the cluster elongation results in the uniaxial magnetic anisotropy in the plane of the implanted layer, which is observed in iron silicide films ion-beam synthesized in the external magnetic field.

The formation of magnetic silicide Fe3Si clusters during ion implantation

International Nuclear Information System (INIS)

Balakirev, N.; Zhikharev, V.; Gumarov, G.

2014-01-01

A simple two-dimensional model of the formation of magnetic silicide Fe 3 Si clusters during high-dose Fe ion implantation into silicon has been proposed and the cluster growth process has been computer simulated. The model takes into account the interaction between the cluster magnetization and magnetic moments of Fe atoms random walking in the implanted layer. If the clusters are formed in the presence of the external magnetic field parallel to the implanted layer, the model predicts the elongation of the growing cluster in the field direction. It has been proposed that the cluster elongation results in the uniaxial magnetic anisotropy in the plane of the implanted layer, which is observed in iron silicide films ion-beam synthesized in the external magnetic field

Facile synthesis of Fe-incorporated CuO nanoarrays with enhanced electrochemical performance for lithium ion full batteries

Energy Technology Data Exchange (ETDEWEB)

Heng, Bojun [Institute of Nano-science and Technology, Central-China Normal University, Wuhan, 430079 (China); Department of Applied Physics, Wuhan University of Science and Technology, Wuhan, 430065 (China); Qing, Chen; Wang, Hai; Sun, Daming; Wang, Bixiao [Institute of Nano-science and Technology, Central-China Normal University, Wuhan, 430079 (China); Tang, Yiwen, E-mail: ywtang@phy.ccnu.edu.cn [Institute of Nano-science and Technology, Central-China Normal University, Wuhan, 430079 (China)

2015-11-15

CuO nanoarrays (CNAs) and Fe-incorporated CuO nanoarrays (FCNAs) were fabricated by hydrothermal method. Addition of Fe salt to the reaction mixture allowed the introduction of iron oxide onto the CNAs surface, which was characterized by XPS and HRTEM. Introducing Fe ion into reaction precursor significantly affected not only the morphologies of as-prepared products but also their electrochemical performance as anode for lithium ion full battery. The FCNAs electrodes showed higher specific capacity and better capacity retention at different current densities than that of CNAs. - Highlights: • Fe-incorporated CuO nanoarrays were fabricated by hydrothermal method. • Fe salt in reaction mixture leads to iron oxides forming on the surface of CuO. • Fe-incorporating improves the lithium ion battery performance of CuO anodes.

Contribution to 57Fe ion implanted garnet study by Moessbauer effect

International Nuclear Information System (INIS)

Kornilios, N.

1986-11-01

Due to because of their numerous physical properties, garnets are often used in new technologies. In order to improve their properties, ion implantation of inert gases has been proved to be a powerful technique to elaborate bubble memories. Recently it has been shown that high doses implanted ions, chemically reacting with the matrix could give interesting results. If the bulk is completely amorphized after implantation, further annealings can recrystallize it. In this study Y 3 F 5 O 12 , Y 3 Al 5 O 12 and Gd 3 Ga 5 O 12 single crystals were 100 keV implanted with 57 Fe ions at doses ranging between 10 16 and 10 17 ions cm -2 . The iron chemical states were determined thanks to Conversion Electron Moessbauer Spectroscopy (CEMS) and it was shown that the alloying elements of the matrix could influence the nature of the created phases. After thermal treatments the sample superficial layers were characterized using CEMS, grazing angle X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Rutherford Backscattering Spectroscopy (RBS). Different annealing stages were put forward: the oxidation of the implanted iron below 650 0 C and the garnet recrystallization around 850 0 C with some iron substitution in the garnet octahedral and tetraedral sites. The overstoechiometric iron forms particles of mixed oxides (FeAl) 2 O 3 , (FeGa) 2 O 3 or particles of pure Fe 2 O 3 oxide depending on the garnet. For the first time it is proved that after annealing around 1200-1300 0 C a complete rebuilding of the garnet matrix can induce for these oxide particles at room temperature a Morin transition [fr

Argon Ion Irradiation Effect on the Magnetic Properties of Fe-Al2O3 Nano Granular Film

Directory of Open Access Journals (Sweden)

Setyo Purwanto

2014-10-01

Full Text Available We studied the effect of Argon (Ar ion irradiation on Fe-Al2O3 nanogranular thin film. X-ray diffraction (XRD patterns show that the ion dose might promote the growth of the Fe2O3 phase from an amorphous phase to a crystalline phase. The magnetic and magnetoresistance properties were investigated using a vibrating sample magnetometer (VSM and a four point probe (FPP. The results suggest that percolation concentration occurred at the 0.55 Fe volume fraction and with a maximum magnetoresistance (MR ratio of 3%. The present MR ratio was lower than that of previous results, which might be related to the existence of the α-Fe2O3 phase promoted by Ar ion irradiation. CEMS spectra show ion irradiation induces changes from superparamagnetic characteristics to ferromagnetic ones, which indicates the spherical growth of Fe particles in the Al2O3 matrix.

Moessbauer of phase separation in FeNi multilayers under ion bombardment

Energy Technology Data Exchange (ETDEWEB)

Amaral, L.; Paesano, A.; Brueckman, M.E. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica; Scorzelli, R.B.; Dominguez, A.B. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Shinjo, T.; Ono, T.; Hosoito, N. [Kyoto Univ. (Japan). Inst. for Chemical Research

1997-01-01

We investigated the effect of noble gas irradiation (He, Ne, Ar and Xe) on the Fe-Ni multilayers with a very thin modulation and nominal composition in the invar region Fe{sub 0.63} Ni{sub 0.37}. The evaluation of the formation/stability of the Fe-Ni phases formed under irradiation with different ions and doses was followed by conversion electron Moessbauer spectroscopy (CEMS). (author). 21 refs., 4 figs., 2 tabs.; e-mail: scorza at novell.cat.cbpf.br.

Systematic measurements of transient fields for W, Os and Pt ions traversing Fe

International Nuclear Information System (INIS)

Stuchbery, A.E.; Heseltine, T.H.; Anderssen, S.S.; Bolotin, H.H.; Byrne, A.P.; Fabricius, B.; Kibedi, T.

1994-01-01

Transient magnetic fields were measured for W, Os and Pt ions traversing iron hosts with average velocities in the range from approximately 1.6 v 0 to 4.8 v 0 (v 0 = c/137, Bohr velocity). Transient fields for W and Os in Fe are consistent with behaviour found for lighter rare-earth ions and are about 20% stronger than those for Pt in Fe over the majority of the velocity range examined. A measurement was made to confirm that possible heavy-ion beam induced attenuations of the transient field are negligible for low-velocity Pt ions excited by Ni beams. Results are discussed in terms of both empirical and model-based parameterizations of the transient field strength. (orig.)

Cationic gemini surfactant-assisted synthesis of hollow Au nanostructures by stepwise reductions.

Science.gov (United States)

Wang, Wentao; Han, Yuchun; Tian, Maozhang; Fan, Yaxun; Tang, Yongqiang; Gao, Mingyuan; Wang, Yilin

2013-06-26

A novel synthetic approach was developed for creating versatile hollow Au nanostructures by stepwise reductions of Au(III) upon the use of cationic gemini surfactant hexamethylene-1,6-bis(dodecyl dimethylammonium bromide) (C12C6C12Br2) as a template agent. It was observed that the Au(I) ions obtained from the reduction of Au(III) by ascorbic acid can assist the gemini surfactant to form vesicles, capsule-like, and tube-like aggregates that subsequently act as soft templates for hollow Au nanostructures upon further reduction of Au(I) to Au(0) by NaBH4. It was demonstrated that the combination of C12C6C12Br2 and Au(I) plays a key role in regulating the structure of the hollow precursors not only because C12C6C12Br2 has a stronger aggregation ability in comparison with its single chain counterpart but also because the electrostatic repulsion between head groups of C12C6C12Br2 is greatly weakened after Au(III) is converted to Au(I), which is in favor of the construction of vesicles, capsule-like, and tube-like aggregates. Compared with solid Au nanospheres, the resultant hollow nanostructures exhibit enhanced electrocatalytic activities in methanol oxidation, following the order of elongated nanocapsule > nanocapsule > nanosphere. Benefiting from balanced interactions between the gemini surfactant and Au(I), this soft-template method may present a facile and versatile approach for the controlled synthesis of Au nanostructures potentially useful for fuel cells and other Au nanodevices.

Improvement of in vitro corrosion and cytocompatibility of biodegradable Fe surface modified by Zn ion implantation

Science.gov (United States)

Wang, Henan; Zheng, Yang; Li, Yan; Jiang, Chengbao

2017-05-01

Pure Fe was surface-modified by Zn ion implantation to improve the biodegradable behavior and cytocompatibility. Surface topography, chemical composition, corrosion resistance and cytocompatibility were investigated. Atomic force microscopy, auger electron spectroscopy and X-ray photoelectron spectroscopy results showed that Zn was implanted into the surface of pure Fe in the depth of 40-60 nm and Fe2O3/ZnO oxides were formed on the outmost surface. Electrochemical measurements and immersion tests revealed an improved degradable behavior for the Zn-implanted Fe samples. An approximately 12% reduction in the corrosion potential (Ecorr) and a 10-fold increase in the corrosion current density (icorr) were obtained after Zn ion implantation with a moderate incident ion dose, which was attributed to the enhanced pitting corrosion. The surface free energy of pure Fe was decreased by Zn ion implantation. The results of direct cell culture indicated that the short-term (4 h) cytocompatibility of MC3T3-E1 cells was promoted by the implanted Zn on the surface.

Fe+ ion irradiation induced changes in structural and magnetic properties of iron films

Directory of Open Access Journals (Sweden)

K. Papamihail

2016-12-01

Full Text Available 490keV Fe+ ion irradiation of 200nm thick Fe films was found to induce both structural and magnetic changes. Both, the lattice constant and the grain size increase as a function of dose and both properties follow the same power law. Irradiation induces a depth dependent magnetic profile consisting of two sublayers. The top Fe sublayer has a magnetic moment higher than that of the Fe before the irradiation whereas the bottom sublayer lower. The two sublayers are connected with the effects of Fe+ irradiation, i.e. the top sublayer with the depth in which mainly radiation damage occurs whereas the bottom one with the implantation of impinging Fe+ ions. The magnetic moments of the two sublayers have a non-monotonous variation with irradiation dose depicting a maximum for the top sublayer and a minimum for the bottom one at 96.2 dpa (‘displacements per atom’. The magnetic moment enhancement/reduction is discussed in relation with the atomic volume variation in the case of atom displacements and/or implantation effects.

Facile synthesis of Fe3O4@PDA core-shell microspheres functionalized with various metal ions: A systematic comparison of commonly-used metal ions for IMAC enrichment.

Science.gov (United States)

Jiang, Jiebing; Sun, Xueni; Li, Yan; Deng, Chunhui; Duan, Gengli

2018-02-01

Metal ions differed greatly in affinity towards phosphopeptides, and thus it is essential to systematically compare the phosphopeptides enrichment ability of different metal ions usually used in the IMAC techniques. In this work, for the first time, eight metal ions, including Nb 5+ , Ti 4+ , Zr 4+ , Ga 3+ , Y 3+ , In 3+ , Ce 4+ , Fe 3+ , were immobilized on the polydopamine (PDA)-coated Fe 3 O 4 (denoted as Fe 3 O 4 @PDA-M n+ ), and systematically compared by the real biosamples, in addition to standard phosphopeptides. Fe 3 O 4 microspheres were synthesized via the solvothermal reaction, followed by self-polymerization of dopamine on the surface. Then through taking advantage of the hydroxyl and amino group of PDA, the eight metal ions were easily adhered to the surface of Fe 3 O 4 @PDA. After characterization, the resultant Fe 3 O 4 @PDA-M n+ microspheres were applied to phosphopeptides enrichment based on the binding affinity between metal ions and phosphopeptides. According to the results, different metal ions presented diverse phosphopeptides enrichment efficiency in terms of selectivity, sensitivity and the enrichment ability from real complex samples, and Fe 3 O 4 @PDA-Nb 5+ and Fe 3 O 4 @PDA-Ti 4+ showed obvious advantages of the phosphopeptides enrichment effect after the comparison. This systematic comparison may provide certain reference for the use and development of IMAC materials in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

Morphology-controlled synthesis of α-FeOOH and its derivatives

International Nuclear Information System (INIS)

Sun Zhengzong; Feng Xiaomiao; Hou Wenhua

2007-01-01

α-FeOOH nanocrystals were synthesized in high yield via a facile and template-free hydrothermal method at low temperature. The morphology and composition of the samples were controlled by slowly releasing the SO 4 2- ions from ammonium persulfate. The rod-like, bundle-like, and urchin-like α-FeOOH nanocrystals could be acquired respectively through a direct hydrothermal route with different quantities of SO 4 2- ions. The rod-like α-FeOOH nanocrystals obtained have a diameter of 5-25 nm and a length of 100-200 nm. When the molar ratio of iron to SO 4 2- was 1:1, the product was pure α-FeOOH phase. However, as the molar ratio was decreased from 1:1 to 1:4, pure FeSO 4 OH·2H 2 O phase was obtained. When the molar ratio was between 1:4 and 1:1, the prepared product was composed of two phases (α-FeOOH and FeSO 4 OH·2H 2 O). After hydrothermally aging the as-synthesized α-FeOOH nanorods at 180 deg. C for 1 d, α-Fe 2 O 3 nanorods were obtained. However, the edge of the α-Fe 2 O 3 nanorods was sword-like and different from the blunt edge of α-FeOOH nanorods due to a recrystallization mechanism

Irradiation Effect of Argon Ion on Interfacial Structure Fe(2nm/Si(tsi=0.5-2 nm Multilayer thin Film

Directory of Open Access Journals (Sweden)

S. Purwanto

2010-04-01

Full Text Available Investigation includes formation of interfacial structure of Fe(2nm/Si(tSi= 0.5-2 nm multilayer thin film and the behavior of antiferromagnetic coupling between Fe layers due to Argon ion irradiation was investigated. [Fe(2nm/Si]30 multilayers (MLs with a thickness of Si spacer 0.5 - 2 nanometer were prepared on n-type (100 Si substrate by the helicon plasma sputtering method. Irradiation were performed using 400keV Ar ion to investigate the behavior of magnetic properties of the Fe/Si MLs. The magnetization measurements of Fe/Si MLs after 400keV Ar ion irradiation show the degradation of antiferromagnetic behavior of Fe layers depend on the ion doses. The Magnetoresistance (MR measurements using by Four Point Probe (FPP method also confirm that MR ratio decrease after ion irradiation. X-ray diffraction (XRD patterns indicate that the intensity of a satellite peak induced by a superlattice structure does not change within the range of ion dose. These results imply that the surface of interface structures after ion irradiation become rough although the layer structures are maintained. Therefore, it is considered that the MR properties of Fe/Si MLs also are due to the metallic superlattice structures such as Fe/Cr and Co/Cu MLs.

On the role of Fe{sup 3+} ions in Fe{sub x}O{sub y}/C catalysts for hydrogen production from the photodehydrogenation of ethanol

Energy Technology Data Exchange (ETDEWEB)

Galindo-Hernández, Félix, E-mail: felixgalindo@gmail.com [Universidad Nacional Autónoma de México (U.N.A.M.), A.P. 20-364, México City, D.F. 01000 (Mexico); Instituto Mexicano del Petróleo (I.M.P.), Eje Central Lázaro Cárdenas Norte 152 Col. San Bartolo Atepehuacan, México City, D.F. 07730 (Mexico); ESIQIE, Instituto Politécnico Nacional, Col. Zacatenco, Av. Politécnico s/n, México City, D.F. 07738 (Mexico); Wang, Jin-An; Chen, Lifang [ESIQIE, Instituto Politécnico Nacional, Col. Zacatenco, Av. Politécnico s/n, México City, D.F. 07738 (Mexico); Bokhimi, Xim [Universidad Nacional Autónoma de México (U.N.A.M.), A.P. 20-364, México City, D.F. 01000 (Mexico); Gómez, Ricardo; Pérez-Larios, Alejandro [Department of Chemistry, Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, A.P. 55-534, México City, D.F. 09340 (Mexico); Nava Entzana, Noel [Instituto Mexicano del Petróleo (I.M.P.), Eje Central Lázaro Cárdenas Norte 152 Col. San Bartolo Atepehuacan, México City, D.F. 07730 (Mexico)

2013-12-15

Graphical abstract: In Fe{sub x}O{sub y}/C photocatalyts important effect of Fe{sup 3+} ions in the photodehydrogenation of the ethano was noticed. -- Highlights: • Iron oxides supported on carbon are photoactive catalysts. • Photoactivity in dehydrogenation of ethanol depends of the amount of Fe{sup 3+} ions present in the catalysts. • The capacity of UV–vis absorbance by the Fe{sub x}O{sub y}/C catalysts is significantly dependent of the amount of Fe{sup 3+} ions. • A maximum of rate constant, K = 2125 μmol h{sup −1}, was obtained from the sample with 30 wt% Fe. -- Abstract: Fe{sub x}O{sub y}/C photocatalysts at different iron content were prepared by the incipient wet impregnation method and calcined at 773 K. The photocatalysts were characterized by means of nitrogen adsorption–desorption isotherms, surface fractal dimension, non-local density functional theory, X-ray diffraction, Rietveld refinement and UV–vis spectroscopy. The photocatalytic activity was evaluated using the photodehydrogenation of ethanol as a model reaction for the production of hydrogen. The specific surface areas of Fe{sub x}O{sub y}/C substrates, with 15, 20 and 30 wt% iron content, diminished from 638 to 490 m{sup 2}/g, as the iron content increased. X-ray diffraction analysis showed that iron oxides coexist as wustite and magnetite in samples with Fe contents of 15 and 20 wt%; for sample with 30 wt% Fe, wustite, magnetite and hematite phases were observed. The photophysical, textural and structural properties were modified by the hematite phase formed by thermal treatment. The Rietveld refinements denoted changes in occupancy of Fe{sup 3+} and Fe{sup 2+} in Fe{sub x}O{sub y} crystallites. A relationship between the Fe{sup 3+} ions content and the reactivity for the hydrogen production from the photodehydrogenation of ethanol (from 1360 to 2125 μmol h{sup −1}), was evidenced.

INTERSTELLAR PICK-UP IONS OBSERVED BETWEEN 11 AND 22 AU BY NEW HORIZONS

International Nuclear Information System (INIS)

Randol, B. M.; McComas, D. J.; Schwadron, N. A.

2013-01-01

We report new observations by the Solar Wind Around Pluto instrument on the New Horizons spacecraft, which measures energy per charge (E/q) spectra of solar wind and interstellar pick-up ions (PUIs) between 11 AU and 22 AU from the Sun. The data provide an unprecedented look at PUIs as there have been very few measurements of PUIs beyond 10 AU. We analyzed the PUI part of the spectra by comparing them to the classic Vasyliunas and Siscoe PUI model. Our analysis indicates that PUIs are usually well-described by this distribution. We derive parameters relevant to PUI studies, such as the ionization rate normalized to 1 AU. Our result for the average ionization rate between 11 and 12 AU agrees with an independently derived average value found during the same time. Later, we find a general increase in the ionization rate, which is consistent with the increase in solar activity. We also calculate the PUI thermal pressure, which appears to be roughly consistent with previous results. Through fitting of the solar wind proton peaks in our spectra, we derive solar wind thermal pressures. Based on our analysis, we predict a ratio of PUI thermal pressure to solar wind thermal pressure just inside the termination shock to be between 100 and >1000.

Gold nanoparticle formation in diamond-like carbon using two different methods: Gold ion implantation and co-deposition of gold and carbon

International Nuclear Information System (INIS)

Salvadori, M. C.; Teixeira, F. S.; Araújo, W. W. R.; Sgubin, L. G.; Cattani, M.; Spirin, R. E.; Brown, I. G.

2012-01-01

We describe work in which gold nanoparticles were formed in diamond-like carbon (DLC), thereby generating a Au-DLC nanocomposite. A high-quality, hydrogen-free DLC thin film was formed by filtered vacuum arc plasma deposition, into which gold nanoparticles were introduced using two different methods. The first method was gold ion implantation into the DLC film at a number of decreasing ion energies, distributing the gold over a controllable depth range within the DLC. The second method was co-deposition of gold and carbon, using two separate vacuum arc plasma guns with suitably interleaved repetitive pulsing. Transmission electron microscope images show that the size of the gold nanoparticles obtained by ion implantation is 3-5 nm. For the Au-DLC composite obtained by co-deposition, there were two different nanoparticle sizes, most about 2 nm with some 6-7 nm. Raman spectroscopy indicates that the implanted sample contains a smaller fraction of sp 3 bonding for the DLC, demonstrating that some sp 3 bonds are destroyed by the gold implantation.

Density functional study of the stability and magnetic behaviour of Au{sub n}TM{sup +} clusters (TM=Au,Sc,Ti,V,Cr,Mn,Fe; 1{<=}n{<=}9)

Energy Technology Data Exchange (ETDEWEB)

Torres, M.B. [Dpto. de Matematicas y Computacion, Univ. de Burgos, Avda. de Cantabria s/n, 09006-Burgos (Spain); Fernandez, E.M.; Balbas, L.C. [Dpto. de Fisica Teorica, Univ. de Valladolid, Prado de la Magdalena s/n, 47011-Valladolid (Spain)

2005-03-01

We study the element- and size-dependent electron stability of Au{sub n}TM{sup +} clusters (TM=Sc,Ti,V,Cr,Mn,Fe,Au; 1{<=}n{<=}9) by means of first-principles density functional calculations. The interplay between the cluster atomic arrangements and their electronic and magnetic structure is investigated for the few lower energy isomeric-states in dependence of the TM-atom and its environment in the cluster. We explain the experimental magic-numbers, observed recently, as well as the trend of the impurity local magnetic moment in dependence with the size of the cluster and the position of the impurity in the host. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Study on tribological behaviors of Fe+ ion implanted in 2024 aluminum alloy

International Nuclear Information System (INIS)

Zhang Aimin; Chen Jianmin; Shi Weidong; Liu Zhenmin

2000-01-01

2024 aluminum alloy was implanted with Fe + ions at a dose of 7x10 16 -3 x 10 17 Fe + /cm 2 . The depth profile of Fe element was investigated by Auger electron spectroscopy (AES). The composition of the surface layer was investigated by XRD with sample-tilting diffraction (STD) mode. The worn out surface was observed by scanning electron microscopy (SEM). Micro-hardness, friction and wear properties have been studied before and after Fe + implantation. An AES analysis shows Fe display Gaussian shape distributions. STD shows Al 5 Fe 2 formed during the implantation. Micro-hardness of surface layer was reduced after implantation, but it did not simply decrease with the increasing implantation doses. The friction and wear tests of implanted and unimplanted samples were carried out on a static-dynamic friction precise measuring apparatus. After implantation, the friction coefficient was reduced from 0.7 to 0.1; the wear resistance was improved remarkably, but decreased with increasing implantation dose. The wear mechanism of the unimplanted sample was adhesive wear, abrasive wear and plastic deformation. The wear reducing effect of Fe + ion induced on 2024 aluminum alloy is mainly attributed to tribooxidation of iron and transfixion of line defect. These two factors prevent the adhesive wear, abrasive wear and plastic deformation of 2024 aluminum alloy

Charge-state distribution in close collisions of 3 MeV C2+ ions with Ag and Au atoms

NARCIS (Netherlands)

Boerma, D.O; Arnoldbik, W.M.; Kabachnik, N.M.; Khodyrev, V.A.

The charge-state distributions of 3 MeV carbon ions scattered over angles of 40 degrees and 60 degrees from sub-monolayers of Ag and Au atoms evaporated on a substrate and from thick layers of Ag and Au have been measured. A close similarity of the charge distributions in all cases is interpreted as

Energy Reflection Coefficients for 5-10 keV He Ions Incident on Au, Ag, and Cu

DEFF Research Database (Denmark)

Schou, Jørgen; Sørensen, H.; Littmark, U.

1978-01-01

The calorimetric deuterium-film method was used for measurements of the energy reflection coefficient γ for normal incidence of 5-10 keV He ions on Cu, Ag and Au. A theoretical calculation of γ by means of transport theory gives fair agreement with the experimental results. The experimental data...... the experimental and theoretical results for the He ions are in acceptable agreement with other experimental and theoretical results. For He ions, the experimental γ-values are 20-30% above the values for hydrogen ions for the same value of ε...

The importance of a Ni correction with ion counter in the double spike analysis of Fe isotope compositions using a 57Fe/58Fe double spike

Science.gov (United States)

Finlayson, V. A.; Konter, J. G.; Ma, L.

2015-12-01

We present a new method capable of measuring iron isotope ratios of igneous materials to high precision by multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) using a 57Fe-58Fe double spike. After sample purification, near-baseline signal levels of nickel are still present in the sample solution, acting as an isobaric interference on 58 amu. To correct for the interference, the minor 60Ni isotope is monitored and used to subtract a proportional 58Ni signal from the total 58 amu beam. The 60Ni signal is difficult to precisely measure on the Faraday detector due to Johnson noise occurring at similar magnitude. This noise-dominated signal is subtracted from the total 58 amu beam, and its error amplified during the double spike correction. Placing the 60Ni beam on an ion counter produces a more precise measurement, resulting in a near-threefold improvement in δ56Fe reproducibility, from ±0.145‰ when measured on Faraday to 0.052‰. Faraday detectors quantify the 60Ni signal poorly, and fail to discern the transient 20Ne40Ar interference visible on the ion counter, which is likely responsible for poor reproducibility. Another consideration is instrumental stability (defined herein as drift in peak center mass), which affects high-resolution analyses. Analyses experiencing large drift relative to bracketing standards often yield nonreplicating data. Based on this, we present a quantitative outlier detection method capable of detecting drift-affected data. After outlier rejection, long-term precision on individual runs of our secondary standard improves to ±0.046‰. Averaging 3-4 analyses further improves precision to 0.019‰, allowing distinction between ultramafic minerals.

Biomass carbon composited FeS2 as cathode materials for high-rate rechargeable lithium-ion battery

Science.gov (United States)

Xu, Xin; Meng, Zhen; Zhu, Xueling; Zhang, Shunlong; Han, Wei-Qiang

2018-03-01

Pyrite FeS2 has long been used as commercial primary lithium batteries at room temperature. To achieve rechargeable FeS2 battery, biomass-carbon@FeS2 composites are prepared using green and renewable auricularia auricula as carbon source through the process of carbonization and sulfuration. The auricularia auricula has strong swelling characteristics to absorb aqueous solution which can effectively absorb Fe ions into its body. FeS2 homogeneously distributed in biomass carbon matrix performs high electronic and ionic conductivity. The specific capacity of biomass-carbon@FeS2 composites remains 850 mAh g-1 after 80 cycles at 0.5C and 700 mAh g-1 at the rate of 2C after 150 cycles. Biomass-carbon@FeS2 composites exhibit high-rate capacity in lithium-ion battery.

Spectroscopic data for highly charged neon-like ions

International Nuclear Information System (INIS)

Li Shichang; Sun Yongsheng; Han Guoxiang; Yang Hanyang

1992-01-01

The purpose of the present work is to provide the immense amount of atomic data needed for applications to the ICF and X-ray laser research work in our institute and for the compilation-evaluation work in Chinese Research Association for Atomic and Molecular Data. Using the non-relativistic Hartree-Fock self-consistent field method including the relativistic mass-velocity and Darwin terms in the Hamiltonian (HFR) proposed by Dr.R.Cowan, we have calculated atomic structure data and spectroscopic data for the Neon-like Fe X VII, Ni X IX, Cu XX Ge XX III and Se XX V ions. In the calculations the configuration-interaction effects were taken into account. The centrifugation average energies, 88 energy levels, all possible electric dipole transition wavelengths, oscillator strengths are presented, and in order to discuss the accuracy of the present results we have also compared them with other works

Evidence of significant covalent bonding in Au(CN)(2)(-).

Science.gov (United States)

Wang, Xue-Bin; Wang, Yi-Lei; Yang, Jie; Xing, Xiao-Peng; Li, Jun; Wang, Lai-Sheng

2009-11-18

The Au(CN)(2)(-) ion is the most stable Au compound known for centuries, yet a detailed understanding of its chemical bonding is still lacking. Here we report direct experimental evidence of significant covalent bonding character in the Au-C bonds in Au(CN)(2)(-) using photoelectron spectroscopy and comparisons with its lighter congeners, Ag(CN)(2)(-) and Cu(CN)(2)(-). Vibrational progressions in the Au-C stretching mode were observed for all detachment transitions for Au(CN)(2)(-), in contrast to the atomic-like transitions for Cu(CN)(2)(-), revealing the Au-C covalent bonding character. In addition, rich electronic structural information was obtained for Au(CN)(2)(-) by employing 118 nm detachment photons. Density functional theory and high-level ab initio calculations were carried out to understand the photoelectron spectra and obtain insight into the nature of the chemical bonding in the M(CN)(2)(-) complexes. Significant covalent character in the Au-C bonding due to the strong relativistic effects was revealed in Au(CN)(2)(-), consistent with its high stability.

Utilization of fish bone as adsorbent of Fe3+ ion by controllable removal of its carbonaceous component

Science.gov (United States)

Nurhadi, M.; Kusumawardani, R.; Widiyowati, I. I.; Wirhanuddin; Nur, H.

2018-05-01

The performance of fish bone to adsorb Fe3+ ion in solution was studied. Powdered fish bone and carbonized fish bone were used as adsorbent. All absorbents were characterized by X-ray diffraction (XRD), IR spectroscopy, nitrogen adsorption, scanning electron microscopy (SEM) and TG analysis. Powdered fish bone and carbonized fish bone were effective as adsorbent for removing Fe3+ ion in solution. The metal adsorptions of Fe3+ ion were 94 and 98% for powdered fish bone and fish bone which carbonized at 400 and 500 °C.

Metal-phthalocyanine ordered layers on Au(110): Metal-dependent adsorption energy

Energy Technology Data Exchange (ETDEWEB)

Massimi, Lorenzo, E-mail: lorenzo.massimi@uniroma1.it; Angelucci, Marco; Gargiani, Pierluigi; Betti, Maria Grazia [Dipartimento di Fisica, Università di Roma La “Sapienza,” 00185 Roma (Italy); Montoro, Silvia [IFIS Litoral, CONICET-UNL, Laboratorio de Fisica de Superficies e Interfaces, Güemes 3450, Santa Fe (Argentina); Mariani, Carlo, E-mail: carlo.mariani@uniroma1.it [Dipartimento di Fisica, CNISM, Università di Roma La “Sapienza,” 00185 Roma (Italy)

2014-06-28

Iron-phthalocyanine and cobalt-phthalocyanine chains, assembled along the Au(110)-(1×2) reconstructed channels, present a strong interaction with the Au metallic states, via the central metal ion. X-ray photoemission spectroscopy from the metal-2p core-levels and valence band high-resolution ultraviolet photoelectron spectroscopy bring to light signatures of the interaction of the metal-phthalocyanine single-layer with gold. The charge transfer from Au to the molecule causes the emerging of a metal-2p core level component at lower binding energy with respect to that measured in the molecular thin films, while the core-levels associated to the organic macrocycle (C and N 1s) are less influenced by the adsorption, and the macrocycles stabilize the interaction, inducing a strong interface dipole. Temperature Programmed Desorption experiments and photoemission as a function of temperature allow to estimate the adsorption energy for the thin-films, mainly due to the molecule-molecule van der Waals interaction, while the FePc and CoPc single-layers remain adsorbed on the Au surface up to at least 820 K.

Pyrene-Phosphonate Conjugate: Aggregation-Induced Enhanced Emission, and Selective Fe3+ Ions Sensing Properties

Directory of Open Access Journals (Sweden)

Sachin D. Padghan

2017-08-01

Full Text Available A new pyrene-phosphonate colorimetric receptor 1 has been designed and synthesized in a one-step process via amide bond formation between pyrene butyric acid chloride and phosphonate-appended aniline. The pyrene-phosphonate receptor 1 showed aggregation-induced enhanced emission (AIEE properties in water/acetonitrile (ACN solutions. Dynamic light scattering (DLS characterization revealed that the aggregates of receptor 1 at 80% water fraction have an average size of ≈142 nm. Field emission scanning electron microscopy (FE-SEM analysis confirmed the formation of spherical aggregates upon solvent evaporation. The sensing properties of receptor 1 were investigated by UV-vis, fluorescence emission spectroscopy, and other optical methods. Among the tested metal ions, receptor 1 is capable of recognizing the Fe3+ ion selectively. The changes in spectral measurements were explained on the basis of complex formation. The composition of receptor 1 and Fe3+ ions was determined by using Job’s plot and found to be 1:1. The receptor 1–Fe3+ complex showed a reversible UV-vis response in the presence of EDTA.

Core–shell Fe3O4–Au magnetic nanoparticles based nonenzymatic ultrasensitive electrochemiluminescence immunosensor using quantum dots functionalized graphene sheet as labels

International Nuclear Information System (INIS)

Liu, Weiyan; Zhang, Yan; Ge, Shenguang; Song, Xianrang; Huang, Jiadong; Yan, Mei; Yu, Jinghua

2013-01-01

Graphical abstract: Core–shell Fe 3 O 4 –Au magnetic nanoparticles and P-GS@QDs were prepared to immobilize Ab 1 and Ab 2 respectively and combined to fabricate a novel sandwich-type ECL immunosensor for detecting CA125 at low concentration. Highlights: ► ECL immunosensor for CA125 based on a microfluidic strategy with a homemade ECL cell was proposed. ► Core–shell Fe 3 O 4 –Au magnetic nanoparticles were employed as the carriers of the primary antibodies. ► CdTe quantum dots functionalized graphene sheet were used for signal amplification. -- Abstract: In this paper, a novel, low-cost electrochemiluminescence (ECL) immunosensor using core–shell Fe 3 O 4 –Au magnetic nanoparticles (AuMNPs) as the carriers of the primary antibody of carbohydrate antigen 125 (CA125) was designed. Graphene sheet (GS) with property of good conductivity and large surface area was a captivating candidate to amplify ECL signal. We successively synthesized functionalized GS by loading large amounts of quantum dots (QDs) onto the poly (diallyldimethyl-ammonium chloride) (PDDA) coated graphene sheet (P-GS@QDs) via self-assembly electrostatic reactions, which were used to label secondary antibodies. The ECL immunosensors coupled with a microfluidic strategy exhibited a wide detection range (0.005–50 U mL −1 ) and a low detection limit (1.2 mU mL −1 ) with the help of an external magnetic field to gather immunosensors. The method was evaluated with clinical serum sample, receiving good correlation with results from commercially available analytical procedure

Mechanistic insights into the interaction between energetic oxygen ions and nanosized ZnFe2O4: XAS-XMCD investigations.

Science.gov (United States)

Singh, Jitendra Pal; Kaur, Baljeet; Sharma, Aditya; Kim, So Hee; Gautam, Sanjeev; Srivastava, Ramesh Chandra; Goyal, Navdeep; Lim, Weol Cheol; Lin, H-J; Chen, J M; Asokan, K; Kanjilal, D; Won, Sung Ok; Lee, Ik-Jae; Chae, Keun Hwa

2018-04-20

as a result of this interaction, as determined from extended X-ray absorption fine structure measurements. These measurements further support the observation of cation migration from AO4 tetrahedra to AO6 octahedra and vice versa. The Fe L-edge magnetic circular dichroism spectra indicate that Fe3+ ions occupying sites in AO4 tetrahedra and BO6 octahedra exhibited antiferromagnetic-like ordering prior to this interaction. The NPs that interacted with energetic O ions displayed a different kind of magnetic ordering.

The formation of magnetic silicide Fe{sub 3}Si clusters during ion implantation

Energy Technology Data Exchange (ETDEWEB)

Balakirev, N. [Kazan National Research Technological University, K.Marx st. 68, Kazan 420015 (Russian Federation); Zhikharev, V., E-mail: valzhik@mail.ru [Kazan National Research Technological University, K.Marx st. 68, Kazan 420015 (Russian Federation); Gumarov, G. [Zavoiskii Physico-Technical Institute of Russian Academy of Sciences, 10/7 Sibirskii trakt st., Kazan 420029 (Russian Federation)

2014-05-01

A simple two-dimensional model of the formation of magnetic silicide Fe{sub 3}Si clusters during high-dose Fe ion implantation into silicon has been proposed and the cluster growth process has been computer simulated. The model takes into account the interaction between the cluster magnetization and magnetic moments of Fe atoms random walking in the implanted layer. If the clusters are formed in the presence of the external magnetic field parallel to the implanted layer, the model predicts the elongation of the growing cluster in the field direction. It has been proposed that the cluster elongation results in the uniaxial magnetic anisotropy in the plane of the implanted layer, which is observed in iron silicide films ion-beam synthesized in the external magnetic field.

Formation and characterization of nanoparticles formed by sequential ion implantation of Au and Co into SiO2

International Nuclear Information System (INIS)

Kluth, P.; Hoy, B.; Johannessen, B.; Dunn, S.G.; Foran, G.J.; Ridgway, M.C.

2007-01-01

Nanoparticles (NPs) were formed by sequential ion implantation of Au and Co into thin SiO 2 . After Au implantation and annealing, Co implantations were carried out at room temperature (RT) and 400 deg. C, respectively, with no subsequent annealing. The NPs were investigated by means of Rutherford backscattering spectroscopy (RBS), transmission electron microscopy (TEM) and extended X-ray absorption fine structure spectroscopy (EXAFS). TEM shows the formation of Co-Au core-shell NPs for the Co implantation at 400 deg. C. EXAFS measurements indicate significant strain in the NPs and a bond-length expansion of the Co-Co bonds in the NP core with a concomitant contraction of the Au-Au bonds in the Au shells. NPs are also observed by TEM for the Co implantation performed at RT, however, a lack of crystallinity is apparent from electron diffraction and EXAFS measurements

Relaxation-Induced Memory Effect of LiFePO4 Electrodes in Li-Ion Batteries.

Science.gov (United States)

Jia, Jianfeng; Tan, Chuhao; Liu, Mengchuang; Li, De; Chen, Yong

2017-07-26

In Li-ion batteries, memory effect has been found in several commercial two-phase materials as a voltage bump and a step in the (dis)charging plateau, which delays the two-phase transition and influences the estimation of the state of charge. Although memory effect has been first discovered in olivine LiFePO 4 , the origination and dependence are still not clear and are critical for regulating the memory effect of LiFePO 4 . Herein, LiFePO 4 has been synthesized by a home-built spray drying instrument, of which the memory effect has been investigated in Li-ion batteries. For as-synthesized LiFePO 4 , the memory effect is significantly dependent on the relaxation time after phase transition. Besides, the voltage bump of memory effect is actually a delayed voltage overshooting that is overlaid at the edge of stepped (dis)charging plateau. Furthermore, we studied the kinetics of LiFePO 4 electrode with electrochemical impedance spectroscopy (EIS), which shows that the memory effect is related to the electrochemical kinetics. Thereby, the underlying mechanism has been revealed in memory effect, which would guide us to optimize two-phase electrode materials and improve Li-ion battery management systems.

Hierarchical paramecium-like hollow and solid Au/Pt bimetallic nanostructures constructed using goethite as template

Science.gov (United States)

Liu, Wei; Repo, Eveliina; Heikkilä, Mikko; Leskelä, Markku; Sillanpää, Mika

2010-10-01

Novel hollow and solid paramecium-like hierarchical Au/Pt bimetallic nanostructures were constructed using goethite as template via a seed-mediated growth method. Transmission electron microscopy (TEM), ξ-potential measurement, UV-vis spectroscopy, energy dispersive x-ray spectroscopy (EDS), ICP-AES measurement, x-ray powder diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) were utilized to systematically characterize the bimetallic nanostructures. It is found that the core structure of the paramecium-like bimetallic nanomaterial is closely related to reducing agent. When ascorbic acid is used as reducing agent, goethite serves as in situ sacrificed template and hollow paramecium-like bimetallic structure is obtained. When NH2OH·HCl is used, solid nanostructure with preserved goethite core is produced. Heating the reaction solution is necessary to obtain the paramecium-like morphology with rough interconnected Pt cilia shell. The thickness of Pt cilia layer can be controlled by adjusting the molar ratio of H2PtCl6 to Au nanoseeds. The overgrowth of the rough Pt cilia is proposed to be via an autocatalytic and three-dimensional heterogeneous nucleation process first through flower-like morphology. Both the hollow and solid hierarchical paramecium-like Au/Pt bimetallic nanostructures show good catalytic activities.

Hierarchical paramecium-like hollow and solid Au/Pt bimetallic nanostructures constructed using goethite as template

International Nuclear Information System (INIS)

Liu Wei; Repo, Eveliina; Sillanpaeae, Mika; Heikkilae, Mikko; Leskelae, Markku

2010-01-01

Novel hollow and solid paramecium-like hierarchical Au/Pt bimetallic nanostructures were constructed using goethite as template via a seed-mediated growth method. Transmission electron microscopy (TEM), ξ-potential measurement, UV-vis spectroscopy, energy dispersive x-ray spectroscopy (EDS), ICP-AES measurement, x-ray powder diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) were utilized to systematically characterize the bimetallic nanostructures. It is found that the core structure of the paramecium-like bimetallic nanomaterial is closely related to reducing agent. When ascorbic acid is used as reducing agent, goethite serves as in situ sacrificed template and hollow paramecium-like bimetallic structure is obtained. When NH 2 OH·HCl is used, solid nanostructure with preserved goethite core is produced. Heating the reaction solution is necessary to obtain the paramecium-like morphology with rough interconnected Pt cilia shell. The thickness of Pt cilia layer can be controlled by adjusting the molar ratio of H 2 PtCl 6 to Au nanoseeds. The overgrowth of the rough Pt cilia is proposed to be via an autocatalytic and three-dimensional heterogeneous nucleation process first through flower-like morphology. Both the hollow and solid hierarchical paramecium-like Au/Pt bimetallic nanostructures show good catalytic activities.

Hierarchical paramecium-like hollow and solid Au/Pt bimetallic nanostructures constructed using goethite as template

Energy Technology Data Exchange (ETDEWEB)

Liu Wei; Repo, Eveliina; Sillanpaeae, Mika [Laboratory of Applied Environmental Chemistry, University of Eastern Finland, Patteristonkatu 1, FI-50100 Mikkeli (Finland); Heikkilae, Mikko; Leskelae, Markku, E-mail: weiliuzk@yahoo.cn, E-mail: mika.sillanpaa@uef.fi [Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki, PO Box 55 (A.I. Virtasen aukio 1), FI-00014, Helsinki (Finland)

2010-10-01

Novel hollow and solid paramecium-like hierarchical Au/Pt bimetallic nanostructures were constructed using goethite as template via a seed-mediated growth method. Transmission electron microscopy (TEM), {xi}-potential measurement, UV-vis spectroscopy, energy dispersive x-ray spectroscopy (EDS), ICP-AES measurement, x-ray powder diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) were utilized to systematically characterize the bimetallic nanostructures. It is found that the core structure of the paramecium-like bimetallic nanomaterial is closely related to reducing agent. When ascorbic acid is used as reducing agent, goethite serves as in situ sacrificed template and hollow paramecium-like bimetallic structure is obtained. When NH{sub 2}OH{center_dot}HCl is used, solid nanostructure with preserved goethite core is produced. Heating the reaction solution is necessary to obtain the paramecium-like morphology with rough interconnected Pt cilia shell. The thickness of Pt cilia layer can be controlled by adjusting the molar ratio of H{sub 2}PtCl{sub 6} to Au nanoseeds. The overgrowth of the rough Pt cilia is proposed to be via an autocatalytic and three-dimensional heterogeneous nucleation process first through flower-like morphology. Both the hollow and solid hierarchical paramecium-like Au/Pt bimetallic nanostructures show good catalytic activities.

Biosorption of Fe (II) and Cd (II) ions from aqueous solution using a ...

African Journals Online (AJOL)

ADOWIE PERE

Biosorption of Fe (II) and Cd (II) ions from aqueous solution using a low cost ... human activities in the environment poses a lot of risk ... ion exchange or reverse osmosis, electrochemical treatment ..... is the adsorption coefficient, n indicates the.

Detailed investigation of Na2.24FePO4CO3 as a cathode material for Na-ion batteries

Science.gov (United States)

Huang, Weifeng; Zhou, Jing; Li, Biao; Ma, Jin; Tao, Shi; Xia, Dingguo; Chu, Wangsheng; Wu, Ziyu

2014-01-01

Na-ion batteries are gaining an increased recognition as the next generation low cost energy storage devices. Here, we present a characterization of Na3FePO4CO3 nanoplates as a novel cathode material for sodium ion batteries. First-principles calculations reveal that there are two paths for Na ion migration along b and c axis. In-situ and ex-situ Fe K-edge X-ray absorption near edge structure (XANES) point out that in Na3FePO4CO3 both Fe2+/Fe3+ and Fe3+/Fe4+ redox couples are electrochemically active, suggesting also the existence of a two-electron intercalation reaction. Ex-situ X-ray powder diffraction data demonstrates that the crystalline structure of Na3FePO4CO3 remains stable during the charging/discharging process within the range 2.0–4.55 V. PMID:24595232

Observations from 1 to 6 AU of Low-Frequency Magnetic Waves due to Newborn Interstellar Pickup Ions Using Ulysses, Voyager and ACE Data

Science.gov (United States)

Smith, C. W.; Aggarwal, P.; Argall, M. R.; Burlaga, L. F.; Bzowski, M.; Cannon, B. E.; Gary, S. P.; Fisher, M. K.; Gilbert, J. A.; Hollick, S. J.; Isenberg, P. A.; Joyce, C. J.; Murphy, N.; Nuno, R. G.; Pine, Z. B.; Richardson, J. D.; Schwadron, N.; Skoug, R. M.; Sokol, J. M.; Taylor, D. K.; Vasquez, B. J.; Zurbuchen, T.

2016-12-01

Wave excitation by newborn interstellar pickup ions (PUIs) play a significant role in theories that attempt to describe IBEX and Voyager observations in the heliosheath as well as solar wind heating. The same dynamic processes can be far-reaching and extend into the inner heliosphere to at least 1AU and likely to smaller heliocentric distances. While the high-resolution magnetic field measurements required to study these waves are not yet available in the heliosheath, we have studied a range of available observations and found evidence of waves due to interstellar PUIs using ACE (1998-2015 at 1 AU), Ulysses (1996-2006 at 2 to 5 AU, high and low latitudes) and Voyager (1978-1979 and 2 to 6 AU) observations. Efforts to extend the Voyager observations to 35 AU are ongoing. We have examined these data sets and report on observations of low-frequency waves that result from newborn interstellar pickup H+ and He+ ions. Although not as common as theory once predicted, we presently have identified 524 independent occurrences. Our conclusion from studying these waves is that they are seen only when the ambient turbulence is sufficiently weak. The instability that leads to the generation of these waves requires a slow accumulation of wave energy over several to tens of hours to achieve the observed wave amplitudes. In regions where the turbulence is moderate to strong, the turbulence consumes the wave energy before it can reach observable levels and transports the energy to the dissipation scales where it heats the background thermal particles. Only intervals with the weakest turbulence will permit energy accumulation over this time scale. These conditions are most often, but not exclusively, achieved in solar wind rarefaction regions.

Equilibrium, kinetics and mechanism of Au3+, Pd2+ and Ag+ ions adsorption from aqueous solutions by graphene oxide functionalized persimmon tannin.

Science.gov (United States)

Wang, Zhongmin; Li, Xiaojuan; Liang, Haijun; Ning, Jingliang; Zhou, Zhide; Li, Guiyin

2017-10-01

In this study, a novel bio-adsorbent (PT-GO) was prepared by functionalization persimmon tannin (PT) with graphene oxide (GO) and the effective adsorption behaviors of Au 3+ , Pd 2+ and Ag + ions from aqueous solution was investigated. The PT-GO was characterized by Fourier transform infrared spectrometer (FTIR), scanning electronic microscope (SEM), thermogravimetric analysis (TGA) and Zeta potential. Many influence factors such as pH value, bio-adsorbent dosage, initial concentration of metal ions and contact time were optimized. The maximum adsorption capacity for Au 3+ , Pd 2+ and Ag + was 1325.09mg/g, 797.66mg/g and 421.01mg/g, respectively. The equilibrium isotherm for the adsorption of Au 3+ and Ag + on PT-GO were found to obey the Langmuir model, while the Freundlich model fitted better for Pd 2+ . The adsorption process of Au 3+ , Pd 2+ presented relatively fast adsorption kinetics with pseudo-second-order equation as the best fitting model, while the pseudo-first-order kinetic model was suitable for describing the adsorption of Ag + . Combination of ion exchange, electrostatic interaction and physical adsorption was the mechanism for adsorption of Au 3+ , Pd 2+ and Ag + onto PT-GO bio-adsorbent. Therefore, the PT-GO bio-adsorbent would be an ideal adsorbent for removal of precious metal ions and broaden the potential applications of persimmon tannin in environmental research. Copyright © 2017 Elsevier B.V. All rights reserved.

Surface and local electronic structure modification of MgO film using Zn and Fe ion implantation

Science.gov (United States)

Singh, Jitendra Pal; Lim, Weon Cheol; Lee, Jihye; Song, Jonghan; Lee, Ik-Jae; Chae, Keun Hwa

2018-02-01

Present work is motivated to investigate the surface and local electronic structure modifications of MgO films implanted with Zn and Fe ions. MgO film was deposited using radio frequency sputtering method. Atomic force microscopy measurements exhibit morphological changes associated with implantation. Implantation of Fe and Zn ions leads to the reduction of co-ordination geometry of Mg2+ ions in host lattice. The effect is dominant at bulk of film rather than surface as the large concentration of implanted ions resides inside bulk. Moreover, the evidences of interaction among implanted ions and oxygen are not being observed using near edge fine structure measurements.

A new multifunctional Schiff base as a fluorescence sensor for Fe{sup 2+} and F{sup −} ions, and a colorimetric sensor for Fe{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Wan, Chin-Feng [School of Medical Applied Chemistry, Chung Shan Medical University, Taichung City 40201, Taiwan (China); Chang, Ya-Ju; Chien, Chih-Yu; Sie, Yi-Wun; Hu, Ching-Han [Department of Chemistry, National Changhua University of Education, Changhua 50058, Taiwan (China); Wu, An-Tai, E-mail: antai@cc.ncue.edu.tw [Department of Chemistry, National Changhua University of Education, Changhua 50058, Taiwan (China)

2016-10-15

A multifunctional Schiff base fluorescent sensor (receptor L) was prepared and its metal ions and anions sensing properties were investigated. Receptor L exhibited an excellent selective fluorescence response toward Fe{sup 2+} and F{sup −}. It also showed colorimetric response (from colorless to yellow) toward Fe{sup 3+} among a series of ions. Moreover, the detection limits of receptor L for Fe{sup 2+} and F{sup −} were determined to be 0.3 ppm and 25.7 ppb, respectively. The two detection limit values were sufficiently low to detect nano-molar concentration of Fe{sup 2+} and F{sup −}.

Uptake of CrO{sub 4}{sup 2-} ions by Fe-treated tri-calcium phosphate

Energy Technology Data Exchange (ETDEWEB)

Serrano G, J.; Ramirez S, J. L.; Bonifacio M, J.; Granados C, F.; Badillo A, V. E., E-mail: juan.serrano@inin.gob.m [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

2010-07-01

CrO{sub 4}{sup 2-} ion adsorption of Fe-treated tri-calcium phosphate was studied by batch experiments as a function of contact time, initial concentration of metal ion and temperature. Adsorption results showed that at ph 5.5 and 1.0 x 10{sup -4} M chromium concentration the adsorption capacity of Fe-treated tri-calcium phosphate for CrO{sub 4}{sup 2-} ions was 7.10 x 10{sup -3} mmol/g. Chromium adsorption data on Fe-treated tri-calcium phosphate at various initial concentration fitted the Freundlich isotherm. By temperature studies the thermodynamic parameters {Delta}H{sup 0}, {Delta}G{sup 0} and {Delta}S{sup 0} were estimated and the obtained results showed that the adsorption reaction was endothermic and spontaneous. (Author)

Rod-like β-FeSi2 phase grown on Si (111) substrate

International Nuclear Information System (INIS)

Han Ming; Tanaka, Miyoko; Takeguchi, Masaki; Furuya, Kazuo

2004-01-01

Pure Fe with coverage of 0.5-2.0 nm was deposited on Si (111) 7x7 surfaces by reactive deposition epitaxy (RDE) in an integrated ultrahigh vacuum (UHV) system. Transmission electron microscopy (TEM) confirmed that the as-deposited epitaxial phase exhibits rod-like and equilateral triangular morphology. The as-deposited phase was identified as c-FeSi 2 by electron diffraction and high-resolution transmission electron microscopy. It was found that there exists lattice distortion in epitaxial c-FeSi 2 phase. Upon annealing at 1073 K, the metastable c-FeSi 2 transforms into equilibrium β-FeSi 2 phase, the latter inherits completely the morphology of c-FeSi 2 phase. Based on RDE and subsequent annealing, a new fabrication technique to grow rod-like semiconducting β-FeSi 2 on a Si substrate has been proposed in the present work

InP:Fe Photoconducting device

Science.gov (United States)

Hammond, Robert B.; Paulter, Nicholas G.; Wagner, Ronald S.

1984-01-01

A photoconducting device fabricated from Fe-doped, semi-insulating InP crystals exhibits an exponential decay transient with decay time inversely related to Fe concentration. Photoconductive gain as high as 5 is demonstrated in photoconducting devices with AuGe and AuSn contacts. Response times from 150 to 1000 picoseconds can be achieved.

Quiet-time 0.04 - 2 MeV/nucleon Ions at 1 AU in Solar Cycles 23 and 24

Science.gov (United States)

Zeldovich, M. A.; Logachev, Y. I.; Kecskeméty, K.

2018-01-01

The fluxes of 3He, 4He, C, O, and Fe ions at low energies (about 0.04 - 2 MeV/nucleon) are studied during quiet periods in Solar Cycles (SC) 23 and 24 using data from the ULEIS/ACE instrument. In selecting quiet periods (the definition is given in Section 2.1), additional data from EPHIN/SOHO and EPAM/ACE were also used. The analysis of the ion energy spectra and their relative abundances shows that their behavior is governed by their first-ionization potential. Substantial differences in the ion energy spectra in two consecutive solar cycles are observed during the quiet periods selected. Quiet-time fluxes are divided into three distinct types according to the {˜} 80 - 320 keV/nucleon Fe/O ratio. Our results confirm the earlier observation that these types of suprathermal particles have different origins, that is, they represent different seed populations that are accelerated by different processes. Except for the solar activity minimum, the Fe/O ratio during quiet-time periods correspond either to the abundances of ions in particle fluxes accelerated in impulsive solar flares or to the mean abundances of elements in the solar corona. At the activity minimum, this ratio takes on values that are characteristic for the solar wind. These results indicate that the background fluxes of low-energy particles in the ascending, maximum, and decay phases of the solar cycle include significant contributions from both coronal particles accelerated to suprathermal energies and ions accelerated in small impulsive solar flares rich in Fe, while the contribution of remnants from earlier SEP events cannot be excluded. The comparison of suprathermal ion abundances during the first five years of SC 23 and SC 24 suggests that the quiet-time and non-quiet fluxes of Fe and 3He were lower in SC 24.

Gold chloride clusters with Au(III) and Au(I) probed by FT-ICR mass spectrometry and MP2 theory.

Science.gov (United States)

Lemke, Kono H

2014-05-07

Microsolvated clusters of gold chloride are probed by electrospray ionization mass spectrometry (ESI-MS) and scalar relativistic electronic structure calculations. Electrospray ionization of aqueous AuCl3 leads to mononuclear clusters of types [AuCl2](+)(H2O)n (n = 0-4), [AuOHCl](+)(H2O)n (n = 0-1) and [AuCl2](+)(HCl)2(H2O)n (n = 0-4). In addition, strong ion signals due to dinuclear [Au2Cl5-xOHx](+)(H2O)n (x = 0-1) are present in ESI mass spectra of aqueous AuCl3, with the abundance of individual dinuclear species controlled by the concentration-dependent variation of the precursor complexes [AuCl2-xOHx](+)(H2O)n and AuCl3. Equilibrium structures, energies and thermodynamic properties of mono- and dinuclear gold clusters have been predicted using MP2 and CCSD(T) theory, and these data have been applied to examine the influence of microsolvation on cluster stability. Specifically, results from CCSD(T) calculations indicate that non-covalently bound ion-neutral complexes Au(+)(Cl2)(H2O)n, with formal Au(I), are the dominant forms of mononuclear gold with n = 0-2, while higher hydrates (n > 2) are covalently bound [AuCl2](+)(H2O)n complexes in which gold exists as Au(III). MP2 calculations show that the lowest energy structure of dinuclear gold is an ion-molecule cluster [Au2Cl(Cl2)2](+) consisting of a single-bridged digold-chloronium ion bound end-on to two dichlorine ligands, with two higher energy isomers, single-bridged [Au2Cl3(Cl2)](+) and double-bridged [Au2Cl5](+) clusters. Finally, AuAu interactions in the singly-bridged clusters [Au2Cl(Cl2)2](+)(H2O)n and [Au2Cl3(Cl2)](+)(H2O)n are examined employing a wide range of computational tools, including natural bond order (NBO) analysis and localized orbital locator (LOL) profiles.

Double Carbon Nano Coating of LiFePO4 Cathode Material for High Performance of Lithium Ion Batteries.

Science.gov (United States)

Ding, Yan-Hong; Huang, Guo-Long; Li, Huan-Huan; Xie, Hai-Ming; Sun, Hai-Zhu; Zhang, Jing-Ping

2015-12-01

Double carbon-coated LiFePO4 (D-LiFePO4/C) composite with sphere-like structure was synthesized through combination of co-precipitation and solid-state methods. Cetyl-trimethyl-ammonium bromide (CTAB) and citric acid served as two kinds of carbon sources in sequence. SEM images demonstrated that double carbon coating had certain influence on the morphology. The thickness of carbon coating on D-LiFePO4/C was about 1.7 nm and the content of carbon was 2.48 wt%, according to HRTEM and TG analysis. The electrochemical impedance spectroscopy analysis indicated that the D-LiFePO4/C composite presented the charge-transfer resistance of 68 Ω and Li ion diffusion coefficient of 2.68 x 10(-13) cm2 S(-1), while the single carbon-coated LiFePO4 (S-LiFePO4/C) exhibited 135.5Ω and 4.03 x 10(-14) cm2 S(-1). Especially, the prepared D-LiFePO4/C electrode showed discharge capacities of 102.9 (10C) and 87.1 (20C) mA h g(-1), respectively, with almost no capacity lost after 400 cycles at 10C, which were much better than those of S-LiFePO4/C composite.

Enhanced lithium-ion storage performance by structural phase transition from two-dimensional rhombohedral Fe_2O_3 to cubic Fe_3O_4

International Nuclear Information System (INIS)

Ren, Yurong; Wang, Jiawei; Huang, Xiaobing; Ding, Jianning

2016-01-01

Highlights: • The rhombohedral Fe_2O_3 transforms to the cubic Fe_3O_4 via a calcination treatment. • Phase structure of anodes has great influences on their electrochemical performances. • Fe_3O_4/reduced graphene oxide shows a high capacity of 825.3 mAh g"−"1 at 50 mA g"−"1. - Abstract: The electrochemical performance of a material varies with its structural phase transition. It is found that the rhombohedral Fe_2O_3 can transform to the cubic Fe_3O_4 via a calcination treatment in a nitrogen atmosphere, and lithium-ion storage performances of Fe_3O_4 get an obvious improvement due to its structural advantages. On the basis of data calculated by X-ray diffraction, the larger unit cell volume as well as the higher void fraction of cubic Fe_3O_4 provides lithium-ions with more transport channels for Li ions diffusion and storage without serious volume change, and thus the cubic Fe_3O_4 delivers an excellent reversible capacity of 921.1 mAh g"−"1 after 15 cycles at the current density of 50 mA g"−"1, which is much higher than 328.3 mAh g"−"1 for the rhombohedral Fe_2O_3. To further enhance the structural stability of electrodes, reduced graphene oxide is introduced. The Fe_3O_4/reduced graphene oxide show an excellent specific capacity of 825.3 mAh g"−"1 after 40 cycles and impressive rate performance of 600 mAh g"−"1 at the current density of 400 mA g"−"1, which are much higher than that of Fe_3O_4 (417 and 300 mAh g"−"1), Fe_2O_3 (137.4 and 95 mAh g"−"1) and Fe_2O_3/reduced graphene oxide (390.1 and 480 mAh g"−"1). These results demonstrate that the structural phase transition and reduced graphene oxide of Fe_3O_4/reduced graphene oxide composites offer unique characteristics suitable for high-performance energy storage application.

Ion-beam mixing and solid-state reaction in Zr-Fe multilayers

International Nuclear Information System (INIS)

Paesano, A. Jr.; Motta, A.T.; Birtcher, R.C.; Ryan, E.A.; Teixeira, S.R.; Bruckmann, M.E.; Amaral, L.

1997-01-01

Vapor-deposited Zr-Fe multilayered thin films with various wavelengths and of overall composition either 50% Fe or Fe-rich up to 57% Fe were either irradiated with 300 keV Kr ions at temperatures from 25 K to 623 K to fluences up to 2 x 10 16 cm -2 , or simply annealed at 773 K in-situ in the Intermediate Voltage Electron microscope At Argonne National Laboratory. Under irradiation, the final reaction product is the amorphous phase in all cases studied, but the dose to amorphization depends on the temperature and on the wavelength. In the purely thermal case (annealing at 773 K), the 50-50 composition produces the amorphous phase but for the Fe-rich multilayers the reaction products depend on the multilayer wavelength. For small wavelength, the amorphous phase is still formed, but at large wavelength the Zr-Fe crystalline intermetallic compounds appear. These results are discussed in terms of existing models of irradiation kinetics and phase selection during solid state reaction

Novel Au- and Ge-based two-dimensional materials formed through topotactic transitions of AlB2-like structures

Science.gov (United States)

Tsetseris, Leonidas

2016-07-01

The topotactic reaction of a layered compound, for example CaGe2, with HCl solution is a common and facile method to produce two-dimensional (2D) materials. In this work we demonstrate with first-principles calculations that this technique can potentially lead to a whole new family of 2D materials starting from three-dimensional crystals with AlB2-like structures. As representative cases, we show here that the de-intercalation of Sc and Ca atoms from ScAuGe and Ca2AuGe3 crystals is strongly exothermic and produces the stable 2D monolayers AuGeH and AuGe3H3, respectively. Remarkably, both metals (AuGeH) and semiconductors (AuGe3H3) can be prepared by this method. Based on the broad availability of AlB2-like structures with varying stoichiometries, there are several possibilities to prepare novel functional 2D materials with suitable topotactic transitions.

Enzymatic glucose sensor based on Au nanoparticle and plant-like ZnO film modified electrode

Energy Technology Data Exchange (ETDEWEB)

Tian, Kun [Nanostructured Materials Research Laboratory, Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT 84112 (United States); Alex, Saji [Nanostructured Materials Research Laboratory, Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT 84112 (United States); Department of Chemistry, Government College for Women, Thiruvananthapuram, Kerala 695014 (India); Siegel, Gene [Nanostructured Materials Research Laboratory, Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT 84112 (United States); Tiwari, Ashutosh, E-mail: tiwari@eng.utah.edu [Nanostructured Materials Research Laboratory, Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT 84112 (United States)

2015-01-01

A novel electrochemical glucose sensor was developed by employing a composite film of plant-like Zinc oxide (ZnO) and chitosan stabilized spherical gold nanoparticles (AuNPs) on which Glucose oxidaze (GOx) was immobilized. The ZnO was deposited on an indium tin oxide (ITO) coated glass and the AuNPs of average diameter of 23 nm were loaded on ZnO as the second layer. The prepared ITO/ZnO/AuNPs/GOx bioelectrode exhibited a low value of Michaelis–Menten constant of 1.70 mM indicating a good bio-matrix for GOx. The studies of electrochemical properties of the electrode using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) showed that, the presence of AuNPs provides significant enhancement of the electron transfer rate during redox reactions. The linear sweep voltammetry (LSV) shows that the ITO/ZnO/AuNPs/GOx based sensor has a high sensitivity of 3.12 μA·mM{sup −1}·cm{sup −2} in the range of 50 mg/dL to 400 mg/dL glucose concentration. The results show promising application of the gold nanoparticle modified plant-like ZnO composite bioelectrode for electrochemical sensing of glucose.

Magnetization, magnetic susceptibility, effective magnetic moment of Fe3+ ions in Bi25FeO39 ferrite

International Nuclear Information System (INIS)

Zatsiupa, A.A.; Bashkirov, L.A.; Troyanchuk, I.O.; Petrov, G.S.; Galyas, A.I.; Lobanovsky, L.S.; Truhanov, S.V.

2014-01-01

Magnetic susceptibility for ferrite Bi 25 FeO 39 is measured at 5–950 K in the magnetic field of 0.86 T. It is shown that Bi 25 FeO 39 is paramagnetic in the temperature range 5−950 K. The saturation magnetization is equal to 5.04μ B per formula unit at 5 K in a magnetic field of 10 T. It is found that at 5−300 K the effective magnetic moment of Fe 3+ ions in Bi 25 FeO 39 is equal to 5.82μ B . - Graphical abstract: The dependence of the magnetization (n, μ B ) on the magnetic field for one formula unit of Bi 25 FeO 39 at 5 K. - Highlights: • Magnetic susceptibility for Bi 25 FeO 39 is measured at 5–950 K in the magnetic field of 0.86 T. • It is shown that Bi 25 FeO 39 is paramagnetic in the temperature range 5−950 K. • The saturation magnetization is equal to 5.04μ B per formula unit at 5 K in a magnetic field of 10 T

Critical process temperatures for resistive InGaAsP/InP heterostructures heavily implanted by Fe or Ga ions

Energy Technology Data Exchange (ETDEWEB)

Fekecs, André [Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, Sherbrooke, QC J1K 0A5 (Canada); Regroupement Québécois sur les Matériaux de Pointe, QC (Canada); Chicoine, Martin [Département de Physique, Université de Montréal, Montréal, QC H3C 3J7 (Canada); Regroupement Québécois sur les Matériaux de Pointe, QC (Canada); Ilahi, Bouraoui [Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, Sherbrooke, QC J1K 0A5 (Canada); SpringThorpe, Anthony J. [Canadian Photonics Fabrication Centre, National Research Council, Ottawa, ON K1A 0R6 (Canada); Schiettekatte, François [Département de Physique, Université de Montréal, Montréal, QC H3C 3J7 (Canada); Regroupement Québécois sur les Matériaux de Pointe, QC (Canada); Morris, Denis [Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, Sherbrooke, QC J1K 0A5 (Canada); Regroupement Québécois sur les Matériaux de Pointe, QC (Canada); and others

2015-09-15

Highlights: • InGaAsP/InP alloys were processed by MeV ion implantation and rapid thermal annealing. • X-ray diffraction and Hall measurement results are compared for several process conditions. • Amorphous layers formed at low implantation temperature. • Dynamic annealing prevented amorphization at implantation above room temperature. • After annealing near 500 °C, sheet resistivities of 10{sup 7} Ω/sq were obtained with low temperature Fe implantation. - Abstract: We report on critical ion implantation and rapid thermal annealing (RTA) process temperatures that produce resistive Fe- or Ga-implanted InGaAsP/InP heterostructures. Two InGaAsP/InP heterostructure compositions, with band gap wavelengths of 1.3 μm and 1.57 μm, were processed by ion implantation sequences done at multiple MeV energies and high fluence (10{sup 15} cm{sup −2}). The optimization of the fabrication process was closely related to the implantation temperature which influences the type of implant-induced defect structures. With hot implantation temperatures, at 373 K and 473 K, X-ray diffraction (XRD) revealed that dynamic defect annealing was strong and prevented the amorphization of the InGaAsP layers. These hot-implanted layers were less resistive and RTA could not optimize them systematically in favor of high resistivity. With cold implantation temperatures, at 83 K and even at 300 K, dynamic annealing was minimized. Damage clusters could form and accumulate to produce resistive amorphous-like structures. After recrystallization by RTA, polycrystalline signatures were found on every low-temperature Fe- and Ga-implanted structures. For both ion species, electrical parameters evolved similarly against annealing temperatures, and resistive structures were produced near 500 °C. However, better isolation was obtained with Fe implantation. Differences in sheet resistivities between the two alloy compositions were less than band gap-related effects. These observations, related

Band-gap tuning and magnetic properties of heterovalent ions (Ba, Sr and Ca) substituted BiFeO_3 nanoparticles

International Nuclear Information System (INIS)

Chauhan, Sunil; Kumar, Manoj; Katyal, S. C.

2016-01-01

A Comparative study of heterovalent Ba, Sr and Ca ions substitution on the structural, vibrational, optical and magnetic properties of BiFeO_3 nanoparticles was carried out. The distorted rhombohedral structure was confirmed from both X-ray diffraction and Raman spectroscopy techniques in pure BiFeO_3 and Bi_0_._8_5A_0_._1_5FeO_3 (A= Ba, Sr and Ca) samples. UV-Visible spectroscopy results show that the band-gap of BiFeO_3 nanoparticles can be tuned by heterovalent ions substitution from 2.12 eV for BiFeO_3 to 2.10, 2.06 and 2.03 eV for Ca, Sr and Ba substituted BiFeO_3 nanoparticles respectively. The magnetic measurements indicate enhancement in magnetization for heterovalent A"2"+ substituted BiFeO_3 samples and the magnetization increases with increase of ionic radius of the substituted ions.

The local structure and magnetic interactions between Fe3+ and V4+ ions in lithium–phosphate glasses

International Nuclear Information System (INIS)

Andronache, Constantin I.

2012-01-01

Electron Paramagnetic Resonance (EPR) provides a useful tool not only as a probe of local structure and short range order in glasses, but also of magnetic interactions in the glasses containing suitable magnetic ions. We have analyzed the spectra of xFe 2 O 3 ·(100 − x)[P 2 O 5 ·Li 2 O] and x(Fe 2 O 3 ·V 2 O 5 )·(100 − x)[P 2 O 5 ·Li 2 O] glass systems, with 0 2 O 5 ·Li 2 O] stands for 50Li 2 O·50P 2 O 5 glass composition. For samples x > 50 mol % a study indicates the presence of crystalline α Fe 2 O 3 in the glasses. Observed spectra have resonance lines centered at g ∼ 4.3 and g ∼ 2.0 typical for Fe 3+ and V 4+ ions present in the oxide glasses. For low contend of transition metal (TM) oxides (Fe 2 O 3 or V 2 O 5 ·Fe 2 O 3 ) the spectra present a hyperfine structure typical for isolated V 4+ ions. With the increasing of TM content, the EPR absorption signal showing hyperfine structure superposed by a broad line without hyperfine structure characteristic for clustered ions. At high TM content, the vanadium hyperfine structure disappears and only the broad line can be observed in the spectra. -- Highlights: ► Lithium phosphate glass with Fe and V ions were investigated by means of EPR. ► The composition dependence of line intensity were investigated. ► The spin Hamiltonian parameters for VO 2+ were evaluated.

Microstructure and tribology of ion-mixed Fe/Ti/C multilayers on AISI 304 stainless steel

International Nuclear Information System (INIS)

Nastasi, M.; Hirvonen, J.P.; Zocco, T.G.; Jervis, T.R.

1991-01-01

A multilayered Fe/Ti/C structure consisting of eleven alternating sublayers, four Fe, four Ti and three C, was ion mixed on an AISI 304 stainless steel substrate with 400 keV Xe 2+ . Complete mixing was observed after an irradiation of 1x10 17 Xe/cm 2 at 550degC. Electron diffraction revealed the formation of the compounds TiC and Fe 3 C and a small amount of an amorphous phase. Some samples were given a second irradiation with 5x10 15 Xe/cm 2 at 0degC. The phases present following the second irradiation were TiC, α-Fe and an amorphous phase. Tribological and nanoindentation measurements revealed that both types of samples possessed similar hardness and friction properties. The ion mixed samples possessed an increased hardness and a decreased friction coefficient relative to untreated polished stainless-steel substrate. However, the wear life of the hot ion mixed sample was consistently longer than the wear life of the sample processed at both 550 and 0degC. These results are explained by differences in adhesive wear which result from differences in the chemical reactivity of the phases formed during ion beam processing. (orig.)

Study of Au- production in a plasma-sputter type negative ion source

International Nuclear Information System (INIS)

Okabe, Yushirou.

1991-10-01

A negative ion source of plasma-sputter type has been constructed for the purpose of studying physical processes which take place in the ion source. Negative ions of gold are produced on the gold target which is immersed in an argon discharge plasma and biased negatively with respect to the plasma. The work function of the target surface was lowered by the deposition of Cs on the target. An in-situ method has been developed to determine the work function of the target surface in the ion source under discharge conditions. The observed minimum work function of a cesiated gold surface in an argon plasma was 1.3 eV, when the negative ion production rate took the maximum value. The production rate increased monotonically and saturated when the surface work function was reduced from 1.9 eV to 1.3 eV. The dependence of Au - production rate on the incident ion energy and on the number of the incident ion was studied. From the experimental results, it is shown that the sputtering process is an important physical process for the negative ion production in the plasma-sputter type negative ion source. The energy distribution function was also measured. When the bias voltage was smaller than 280 V, the high energy component in the distribution decreased as the target voltage was decreased. Therefore, the energy spread ΔE, of the observed negative ion energy distribution also decreased. This tendency is also seen in the energy spectrum of Cu atoms sputtered in normal direction by Ar + ions. (J.P.N.)

In situ ion channeling study of gallium disorder and gold profiles in Au-implanted GaN

International Nuclear Information System (INIS)

Jiang, W.; Weber, W. J.; Thevuthasan, S.

2000-01-01

Disorder accumulation and annealing behavior on the Ga sublattice in gallium nitride (GaN) implanted with 1.0 MeV Au 2+ (60 degree sign off surface normal) at 180 or 300 K have been studied using in situ Rutherford backscattering spectrometry in a -channeling geometry. Complete amorphization in GaN is attained at 6.0 and 20 Au 2+ /nm 2 for irradiation at 180 and 300 K, respectively. A saturation in the Ga disorder at and behind the damage peak was observed at intermediate ion fluences at both 180 and 300 K. No measurable thermal recovery was found at 300 K for the full range of damage produced at 180 K. However, distinct epitaxial regrowth in the bulk and Ga reordering at surface occurred after annealing at 870 K. The implanted Au readily diffuses into the highly damaged regions at elevated temperatures, and the redistribution of the Au atoms in the implanted GaN varies with the damage profiles. A double-peak Au profile developed with the maxima located in the amorphous surface region and near the Au mean projected range. The result is interpreted as Au atom diffusion into the amorphous regime near the surface and Au trapping at irradiation-induced defects in the crystal structure. This trapping effect is also evidenced in this study by the suppressed recovery of the Au-decorated disorder in GaN. (c) 2000 American Institute of Physics

Storage and Effective Migration of Li-Ion for Defected β-LiFePO4 Phase Nanocrystals.

Science.gov (United States)

Guo, Hua; Song, Xiaohe; Zhuo, Zengqing; Hu, Jiangtao; Liu, Tongchao; Duan, Yandong; Zheng, Jiaxin; Chen, Zonghai; Yang, Wanli; Amine, Khalil; Pan, Feng

2016-01-13

Lithium iron phosphate, a widely used cathode material, crystallizes typically in olivine-type phase, α-LiFePO4 (αLFP). However, the new phase β-LiFePO4 (βLFP), which can be transformed from αLFP under high temperature and pressure, is originally almost electrochemically inactive with no capacity for Li-ion battery, because the Li-ions are stored in the tetrahedral [LiO4] with very high activation barrier for migration and the one-dimensional (1D) migration channels for Li-ion diffusion in αLFP disappear, while the Fe ions in the β-phase are oriented similar to the 1D arrangement instead. In this work, using experimental studies combined with density functional theory calculations, we demonstrate that βLFP can be activated with creation of effective paths of Li-ion migration by optimized disordering. Thus, the new phase of βLFP cathode achieved a capacity of 128 mAh g(-1) at a rate of 0.1 C (1C = 170 mA g(-1)) with extraordinary cycling performance that 94.5% of the initial capacity retains after 1000 cycles at 1 C. The activation mechanism can be attributed to that the induced disorder (such as FeLiLiFe antisite defects, crystal distortion, and amorphous domains) creates new lithium migration passages, which free the captive stored lithium atoms and facilitate their intercalation/deintercalation from the cathode. Such materials activated by disorder are promising candidate cathodes for lithium batteries, and the related mechanism of storage and effective migration of Li-ions also provides new clues for future design of disordered-electrode materials with high capacity and high energy density.

Precise measurements and theoretical calculations of He-like ion resonance line satellites radiated from Be-, B-, C-, N-, O-, and F-like ions

International Nuclear Information System (INIS)

Faenov, A.Ya.; Pikuz, S.A.; Shlyaptseva, A.S.

1994-01-01

Spectra with spectral resolution λ/Δλ∼ =3000-7000 in the vicinity of the He-like ion resonance lines Mg, Al, Si, P, S were obtained in CO 2 laser-produced plasma. The wavelengths of these satellites were measured and compared with numerical calculations. Identification of lines or a group of overlapping lines was performed. Twenty-two transitions of dielectronic satellites for Be-like ions, 41 transitions for B-like, 40 transitions for C-like, 22 transitions for N-like, 12 transitions for O-like ions and 2 transitions for F-like ions were identified. The average between theoretical and experimental wavelengths was ±(0.0005-0.001) A, but in some cases it was ±(0.002-0.003) A. (orig.)

Precise measurements and theoretical calculations of He-like ion resonance line satellites radiated from Be-, B-, C-, N-, O-, and F-like ions

Energy Technology Data Exchange (ETDEWEB)

Faenov, A.Ya. [MISDC, NPO `VNIIFTRI`, Mendeleevo (Russian Federation); Pikuz, S.A. [P.N. Lebedev Physical Inst., Russian Academy of Sciences, Moscow (Russian Federation); Shlyaptseva, A.S. [Inst. of Technical Glasses, Moscow (Russian Federation)

1994-01-01

Spectra with spectral resolution {lambda}/{Delta}{lambda}{approx} =3000-7000 in the vicinity of the He-like ion resonance lines Mg, Al, Si, P, S were obtained in CO{sub 2} laser-produced plasma. The wavelengths of these satellites were measured and compared with numerical calculations. Identification of lines or a group of overlapping lines was performed. Twenty-two transitions of dielectronic satellites for Be-like ions, 41 transitions for B-like, 40 transitions for C-like, 22 transitions for N-like, 12 transitions for O-like ions and 2 transitions for F-like ions were identified. The average between theoretical and experimental wavelengths was {+-}(0.0005-0.001) A, but in some cases it was {+-}(0.002-0.003) A. (orig.).

A single low dose of Fe ions can cause long-term biological responses in NL20 human bronchial epithelial cells

Energy Technology Data Exchange (ETDEWEB)

Cao, Qianlin; Wang, Jingdong; Cao, Jianping; Yang, Hongying [Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, School of Radiation Medicine and Protection, Suzhou, Jiangsu (China); Liu, Wei [Soochow University, Department of Radiotherapy and Oncology, Second Affiliated Hospital, Suzhou, Jiangsu (China)

2018-03-15

Space radiation cancer risk may be a potential obstacle for long-duration spaceflight. Among all types of cancer space radiation may induce, lung cancer has been estimated to be the largest potential risk. Although previous animal study has shown that Fe ions, the most important contributor to the total dose equivalent of space radiation, induced a higher incidence of lung tumorigenesis per dose than X-rays, the underlying mechanisms at cellular level remained unclear. Therefore, in the present study, we investigated long-term biological changes in NL20 human bronchial epithelial cells after exposure to Fe ion or X-ray irradiation. We found that compared with sham control, the progeny of NL20 cells irradiated with 0.1 Gy of Fe ions showed slightly increased micronucleus formation, significantly decreased cell proliferation, disturbed cell cycle distribution, and obviously elevated intracellular ROS levels accompanied by reduced SOD1 and SOD2 expression, but the progeny of NL20 cells irradiated with 0.9 Gy of X-rays did not show any significant changes. More importantly, Fe ion exposure caused much greater soft-agar colony formation than X-rays did in the progeny of irradiated NL20 cells, clearly suggesting higher cell transformation potential of Fe ions compared with X-rays. These data may shed the light on the potential lung tumorigenesis risk from Fe ion exposure. In addition, ATM inhibition by Ku55933 reversed some of the changes in the progeny of Fe ion-irradiated cells but not others such as soft-agar colony formation, suggesting complex processes from DNA damage to carcinogenesis. These data indicate that even a single low dose of Fe ions can induce long-term biological responses such as cell transformation, etc., suggesting unignorable health risk from space radiation to astronauts. (orig.)

Characterization of recombinant nitrile-specifier proteins (NSPs) of Arabidopsis thaliana: dependency on Fe(II) ions and the effect of glucosinolate substrate and reaction conditions.

Science.gov (United States)

Kong, Xiang Yi; Kissen, Ralph; Bones, Atle M

2012-12-01

Glucosinolates are plant secondary metabolites that are part of a plant defence system against pathogens and pests, the myrosinase-glucosinolate system, in which glucosinolates get activated by enzymic degradation through thioglucoside glucohydrolases called myrosinases. Epithiospecifier protein (ESP) and nitrile-specifier proteins (NSPs) divert myrosinase-catalyzed hydrolysis of a given glucosinolate from the formation of isothiocyanate to that of epithionitrile and/or nitrile. As the biological activity of glucosinolate hydrolysis products varies considerably, a detailed characterization of these specifier proteins is of utmost importance to understand their biological role. Therefore, the Arabidopsis thaliana AtNSP1, AtNSP2 and AtNSP5 and a supposed ancestor protein AtNSP-like1 were expressed in Escherichia coli and the activity of the purified recombinant proteins was tested in vitro on three highly different glucosinolates and compared to that of purified AtESP. As previously reported, only AtESP showed epithiospecifier activity on 2-propenylglucosinolate. We further confirmed that purified AtNSP1, AtNSP2 and AtNSP5, but not the ancestor AtNSP-like1 protein, show nitrile-specifier activity on 2-propenylglucosinolate and benzylglucosinolate. We now show for the first time that in vitro AtNSP1, AtNSP2 and AtNSP5 are able to generate nitrile from indol-3-ylmethylglucosinolate. We also tested the effect of different Fe(II) ion concentrations on the nitrile-specifier activity of purified AtNSP1, AtNSP2 and AtNSP5 on 2-propenylglucosinolate and benzylglucosinolate. AtNSP-related nitrile production was highly dependent on the presence of Fe(II) ions in the reaction assay. In the absence of added Fe(II) ions nitriles were only detected when benzylglucosinolate was incubated with AtNSP1. While AtNSP1 also exhibited overall higher nitrile-specifier activity than AtNSP2 and AtNSP5 at a given Fe(II) ion concentration, the pattern of nitrile formation in relation to Fe

Indirect mechanisms in electron-impact ionization of multiply charged ions

International Nuclear Information System (INIS)

Phaneuf, R.A.; Gregory, D.C.

1986-09-01

The important role of indirect-ionization mechanisms in electron-impact ionization of multiply charged ions has been emphasized by some recent experiments conducted with the ORNL-ECR multicharged ion source. Illustrative examples of investigations of the Mg-isoelectronic and Fe-isonuclear sequences are presented and compared with the results of detailed theoretical calculations. New experimental data is also presented concerning the role of resonance effects in the ionization of Li-like O 5+ and Na-like Fe 15+ ions

Effect of swift heavy ion-irradiation on Cr/Fe/Ni multilayers

International Nuclear Information System (INIS)

Gupta, Ratnesh; Gupta, Ajay; Avasthi, D.K.; Principi, G.; Tosello, C.

1999-01-01

A multilayer film having overall composition Fe 50 Cr 25 Ni 25 , was irradiated successively by 80 MeV Si ions and Ag ions of 150 and 200 MeV energy. The energy deposited in the multilayer in the form of electronic excitations results in significant modification at the interfaces. The interfacial roughness increases in the system after the irradiations as revealed by X-ray reflectivity measurement. Moessbauer measurements provide evidence of intermixing after the irradiation by 200 MeV Ag ions. Comparison of heavy ion irradiated multilayer has been done with annealed and low energy ion irradiated samples. Results suggest that the phases formed at the interfaces of iron as a result of electronic energy loss are similar to those in the cases of thermal diffusion and keV energy ion beam irradiation

Iron and chlorine as guides to stratiform Cu-Co-Au deposits, Idaho Cobalt Belt, USA

Science.gov (United States)

Nash, J.T.; Connor, J.J.

1993-01-01

The Cu-Co-Au deposits of the Idaho Cobalt Belt are in lithostratigraphic zones of the Middle Proterozoic Yellowjacket Formation characterized by distinctive chemical and mineralogical compositions including high concentrations of Fe (15- > 30 wt. percent Fe2O3), Cl (0.1-1.10 wt. percent), and magnetite or biotite (> 50 vol. percent). The Cu-Co-Au deposits of the Blackbird mine are stratabound in Fe-silicate facies rocks that are rich in biotite, Fe, and Cl, but stratigraphically equivalent rocks farther than 10 km from ore deposits have similar compositions. A lower lithostratigraphic zone containing magnetite and small Cu-Co-Au deposits extends for more than 40 km. The Fe-rich strata are probably exhalative units related to mafic volcanism and submarine hot springs, but the origin of the high Cl concentrations is less clear. Former chlorine-rich pore fluids are suggested by the presence of supersaline fluid inclusions, by Cl-rich biotite and scapolite (as much as 1.87 percent Cl in Fe-rich biotite), and by high Cl concentrations in rock samples. Chlorine is enriched in specific strata and in zones characterized by soft-sediment deformation, thus probably was introduced during sedimentation or diagenesis. Unlike some metasedimentary rocks containing scapolite and high Cl, the Yellowjacket Formation lacks evidence for evaporitic strata that could have been a source of Cl. More likely, the Cl reflects a submarine brine that carried Fe, K, and base metals. Strata containing anomalous Fe-K-Cl are considered to be a guide to sub-basins favorable for the occurrence of stratiform base-metal deposits. ?? 1993 Springer-Verlag.

Preparation and Characterisation of LiFePO4/CNT Material for Li-Ion Batteries

Directory of Open Access Journals (Sweden)

Rushanah Mohamed

2011-01-01

Full Text Available Li-ion battery cathode materials were synthesised via a mechanical activation and thermal treatment process and systematically studied. LiFePO4/CNT composite cathode materials were successfully prepared from LiFePO4 material. The synthesis technique involved growth of carbon nanotubes onto the LiFePO4 using a novel spray pyrolysis-modified CVD technique. The technique yielded LiFePO4/CNT composite cathode material displaying good electrochemical activity. The composite cathode exhibited excellent electrochemical performances with 163 mAh/g discharge capacity with 94% cycle efficiency at a 0.1 C discharge rate in the first cycle, with a capacity fade of approximately 10% after 30 cycles. The results indicate that carbon nanotube addition can enable LiFePO4 to display a higher discharge capacity at a fast rate with high efficiency. The research is of potential interest for the application of carbon nanotubes as a new conducting additive in cathode preparation and for the development of high-power Li-ion batteries for hybrid electric vehicles.

High-capacity FeTiO3/C negative electrode for sodium-ion batteries with ultralong cycle life

Science.gov (United States)

Ding, Changsheng; Nohira, Toshiyuki; Hagiwara, Rika

2018-06-01

The development of electrode materials which improve both the energy density and cycle life is one of the most challenging issues facing the practical application of sodium-ion batteries today. In this work, FeTiO3/C nanoparticles are synthesized as negative electrode materials for sodium-ion batteries. The electrochemical performance and charge-discharge mechanism of the FeTiO3/C negative electrode are investigated in an ionic liquid electrolyte at 90 °C. The FeTiO3/C negative electrode delivers a high reversible capacity of 403 mAh g-1 at a current rate of 10 mA g-1, and exhibits high rate capability and excellent cycling stability for up to 2000 cycles. The results indicate that FeTiO3/C is a promising negative electrode material for sodium-ion batteries.

Effect of Silicon on Activity Coefficients of Siderophile Elements (P, Au, Pd, As, Ge, Sb, and In) in Liquid Fe, with Application to Core Formation

Science.gov (United States)

Righter, K.; Pando, K.; Danielson, L. R.; Humayun, M.; Righter, M.; Lapen, T.; Boujibar, A.

2016-01-01

Earth's core contains approximately 10 percent light elements that are likely a combination of S, C, Si, and O, with Si possibly being the most abundant. Si dissolved into Fe liquids can have a large effect on the magnitude of the activity coefficient of siderophile elements (SE) in Fe liquids, and thus the partitioning behavior of those elements between core and mantle. The effect of Si can be small such as for Ni and Co, or large such as for Mo, Ge, Sb, As. The effect of Si on many siderophile elements is unknown yet could be an important, and as yet unquantified, influence on the core-mantle partitioning of SE. Here we report new experiments designed to quantify the effect of Si on the partitioning of P, Au, Pd, and many other SE between metal and silicate melt. The results will be applied to Earth, for which we have excellent constraints on the mantle siderophile element concentrations.

PVC-membrane potentiometric sensors based on a recently synthesized Schiff base for Fe(III ion

Directory of Open Access Journals (Sweden)

S. Yousef Ebrahimipur

2012-12-01

Full Text Available A potentiometric iron sensor based on the use 3-(2-diethylamino-ethylimino-1,3-dihydro-indol-2-one (DEDIO as an ionophore in poly(vinyl chloride (PVC matrix, is reported. The plasticized membrane sensor exhibits a Nernstian response for Fe(III ions over a wide concentration range (2.0 × 10-6 - 5.0 × 10-2 M with a super Nernstian slope of 26(plus or minus 1 mV per decade. It has a fast response time of less than 12 s and can be used for ten weeks without any considerable divergences in its potentials the electrode can be used in the pH range 4.5-8.0. The proposed sensor shows fairly good discriminating ability towards Fe(III ion in comparison with a large number of alkali, alkaline earth, transition and heavy metal ions. The sensor was used as indicator electrode in potentiometric titration of Fe(III ions vs. EDTA.DOI: http://dx.doi.org/10.4314/bcse.v26i1.7

Synthesis of Fulvic Acid-Coated Magnetite (Fe3O4–FA and Its Application for the Reductive Adsorption of [AuCl4]–

Directory of Open Access Journals (Sweden)

Philip Anggo Krisbiantoro

2017-11-01

Full Text Available Fulvic acid-coated magnetite (Fe3O4–FA has been synthesized through coprecipitation method using NH4OH. Synthesis conducted by cheap and environmentally friendly preparation used iron salts and extracted fulvic acid (FA from Peat soil of Rawa Pening, Central Java, Indonesia. Characterization using FT–IR indicated that the coating of FA on Fe3O4 occurred through the formation of chemical bond between iron of Fe3O4 and carboxyl group of FA. The XRD measurement indicated that coated Fe3O4 successfully dispersed in smaller size than uncoated Fe3O4, i.e. from 16.67 to 14.84 nm for Fe3O4 and Fe3O4–FA, respectively. Synthesized Fe3O4–FA has pHPZC 6.37 and stable at pH > 3.0. The extracted FA has total acidity 866.61 cmol kg–1, –COOH content 229.77 cmol kg–1 and –OH content 636.84 cmol kg–1. Fe3O4–FA has total acidity 494.86 cmol kg–1, –COOH content 67.80 cmol kg–1 and –OH content 427.06 cmol kg–1. The adsorption rate constant (k of [AuCl4]– on Fe3O4–A according to the Ho kinetic model was 8006.53 g mol–1 min–1. The adsorption capacity (qmax according to Langmuir isotherm model was 1.24 × 10–4 mol g–1. The presence of reduction towards the adsorbed [AuCl4]– was shown by the appearance of peaks at 2θ: 37.41; 43.66; 64.25, and 76.67° in the XRD diffractogram.

Measurement of the H3Λ lifetime in Au+Au collisions at the BNL Relativistic Heavy Ion Collider

Science.gov (United States)

Adamczyk, L.; Adams, J. R.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Ajitanand, N. N.; Alekseev, I.; Alford, J.; Anderson, D. M.; Aoyama, R.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Barish, K.; Behera, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Brown, D.; Bryslawskyj, J.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chankova-Bunzarova, N.; Chatterjee, A.; Chattopadhyay, S.; Chen, X.; Chen, X.; Chen, J. H.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; Dedovich, T. G.; Deng, J.; Deppner, I. M.; Derevschikov, A. A.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Dunlop, J. C.; Efimov, L. G.; Elsey, N.; Engelage, J.; Eppley, G.; Esha, R.; Esumi, S.; Evdokimov, O.; Ewigleben, J.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Federicova, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Fujita, J.; Fulek, L.; Gagliardi, C. A.; Geurts, F.; Gibson, A.; Girard, M.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Guryn, W.; Hamad, A. I.; Hamed, A.; Harlenderova, A.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Herrmann, N.; Hirsch, A.; Horvat, S.; Huang, B.; Huang, T.; Huang, X.; Huang, H. Z.; Humanic, T. J.; Huo, P.; Igo, G.; Jacobs, W. W.; Jentsch, A.; Jia, J.; Jiang, K.; Jowzaee, S.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kapukchyan, D.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z.; Kikoła, D. P.; Kim, C.; Kisel, I.; Kisiel, A.; Kochenda, L.; Kocmanek, M.; Kollegger, T.; Kosarzewski, L. K.; Kraishan, A. F.; Krauth, L.; Kravtsov, P.; Krueger, K.; Kulathunga, N.; Kumar, L.; Kvapil, J.; Kwasizur, J. H.; Lacey, R.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, W.; Li, Y.; Li, C.; Lidrych, J.; Lin, T.; Lisa, M. A.; Liu, F.; Liu, P.; Liu, Y.; Liu, H.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Luo, S.; Ma, G. L.; Ma, L.; Ma, R.; Ma, Y. G.; Magdy, N.; Majka, R.; Mallick, D.; Margetis, S.; Markert, C.; Matis, H. S.; Mayes, D.; Meehan, K.; Mei, J. C.; Miller, Z. W.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mizuno, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nemes, D. B.; Nie, M.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Nonaka, T.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Pruthi, N. K.; Przybycien, M.; Putschke, J.; Quintero, A.; Ramachandran, S.; Ray, R. L.; Reed, R.; Rehbein, M. J.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roth, J. D.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Salur, S.; Sandweiss, J.; Saur, M.; Schambach, J.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Schweid, B. R.; Seger, J.; Sergeeva, M.; Seto, R.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Shen, W. Q.; Shi, S. S.; Shi, Z.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stewart, D. J.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Sugiura, T.; Sumbera, M.; Summa, B.; Sun, Y.; Sun, X.; Sun, X. M.; Surrow, B.; Svirida, D. N.; Tang, A. H.; Tang, Z.; Taranenko, A.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vasiliev, A. N.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, G.; Wang, Y.; Wang, F.; Wang, Y.; Webb, G.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, G.; Xie, W.; Xu, Y. F.; Xu, J.; Xu, Q. H.; Xu, N.; Xu, Z.; Yang, S.; Yang, Y.; Yang, C.; Yang, Q.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, Z.; Zhang, J.; Zhang, S.; Zhang, S.; Zhang, J.; Zhang, Y.; Zhang, X. P.; Zhang, J. B.; Zhao, J.; Zhong, C.; Zhou, L.; Zhou, C.; Zhu, X.; Zhu, Z.; Zyzak, M.; STAR Collaboration

2018-05-01

An improved measurement of the H3Λ lifetime is presented. In this paper, the mesonic decay modes H3Λ→3He + π- and H3Λ→d +p +π- are used to reconstruct the H3Λ from Au+Au collision data collected by the STAR collaboration at Relativistic Heavy Ion Collider (RHIC). A minimum χ2 estimation is used to determine the lifetime of τ = 142-21+24(stat .) ±29 (syst .) ps. This lifetime is about 50% shorter than the lifetime τ =263 ±2 ps of a free Λ , indicating strong hyperon-nucleon interaction in the hypernucleus system. The branching ratios of the mesonic decay channels are also determined to satisfy B.R . (3He+π-)/(B.R . (3He+π-)+B.R . (d +p +π-)) = 0.32 ±0.05 (stat .) ±0.08 (syst .) . Our ratio result favors the assignment J (H3Λ) =1/2 over J (H3Λ) =3/2 . These measurements will help to constrain models of hyperon-baryon interactions.

Solvent extraction of Au(III) for preparation of a carrier-free multitracer and an Au tracer from an Au target

International Nuclear Information System (INIS)

Weginwar, R.G.; Kobayashi, Y.; Ambe, S.; Liu, B.; Enomoto, S.; Ambe, F.

1996-01-01

Separation of Au(III) and various carrier-free radionuclides by solvent extraction was investigated using an Au target irradiated by an energetic heavy-ion beam. Percentage extraction of Au(III) and coextraction of the radionuclides were determined with varying parameters such as kinds of solvent, molarity of HCl or pH, and Au concentration. Under the conditions where Au(III) was effectively extracted, namely extraction with ethyl acetate or isobutyl methyl ketone from 3 mol*dm -3 HCl, carrier-free radionuclides of many elements were found to be more or less coextracted. Coextraction of radionuclides of some elements was found to increase with an increase in the concentration of Au(III). This finding is ascribed to the formation of strong association of the complex of these elements with chloroauric acid. In order to avoid serious loss of these elements by the extraction, lowering of the Au(III) concentration or the use of a masking agent such as sodium citrate is necessary. Gold(III) was shown to be effectively back extracted with a 0.1 mol*dm -3 aqueous solution of 2-amino-2-hydroxymethyl-1,3-propanediol. Thus, a radiochemical procedure has been established for preparing a carrier-free multitracer and an Au tracer with carrier form from an Au target irradiated with a heavy-ion beam. Both tracers are now used individually for chemical and biological experiments. (author). 22 refs., 3 figs., 2 tabs

Enhancement of oxygen reduction at Fe tetrapyridyl porphyrin by pyridyl-N coordination to transition metal ions

International Nuclear Information System (INIS)

Maruyama, Jun; Baier, Claudia; Wolfschmidt, Holger; Bele, Petra; Stimming, Ulrich

2012-01-01

One of the promising candidates as noble-metal-free electrode catalysts for polymer electrolyte fuel cells (PEFCs) is a carbon material with nitrogen atoms coordinating iron ions embedded on the surface (Fe-N x moiety) as the active site, although the activity is insufficient compared to conventional platinum-based electrocatalysts. In order to obtain fundamental information on the activity enhancement, a simple model of the Fe-N x active site was formed by adsorbing 5,10,15,20-Tetrakis(4-pyridyl)-21H,23H-porphine iron(III) chloride (FeTPyPCl) on the basal plane of highly oriented pyrolytic graphite (HOPG), and cathodic oxygen reduction was investigated on the surface in 0.1 M HClO 4 . The catalytic activity for oxygen reduction was enhanced by loading transition metal ions (Co 2+ , Ni 2+ , Cu 2+ ) together with FeTPyPCl. The X-ray photoelectron spectrum of the surface suggested that the metal was coordinated by the pyridine-N. The enhancement effect of the transition metals was supported by two different measurements: oxygen reduction at HOPG in 0.1 M HClO 4 dissolving FeTPyPCl and the metal ions; oxygen reduction in 0.1 M HClO 4 at the subsequently well-rinsed and dried HOPG. The ultraviolet–visible spectrum for the solution also suggested the coordination between the pyridyl-N and the metal ions. The oxygen reduction enhancement was attributed to the electronic interaction between the additional transition metal and the Fe center of the porphyrin through the coordination bonds. These results implied that the improvement of the activity of the noble-metal-free catalyst would be possible by the proper introduction of the transition metal ions around the active site.

AuPd Bimetallic Nanocrystals Embedded in Magnetic Halloysite Nanotubes: Facile Synthesis and Catalytic Reduction of Nitroaromatic Compounds

Directory of Open Access Journals (Sweden)

Lei Jia

2017-10-01

Full Text Available In this research, a facile and effective approach was developed for the preparation of well-designed AuPd alloyed catalysts supported on magnetic halloysite nanotubes (HNTs@Fe3O4@AuPd. The microstructure and the magnetic properties of HNTs@Fe3O4@AuPd were confirmed by transmission electron microscopy (TEM, high resolution TEM (HRTEM, energy-dispersive X-ray spectroscopy (EDS, and vibrating sample magnetometry (VSM analyses. The catalysts, fabricated by a cheap, environmentally friendly, and simple surfactant-free formation process, exhibited high activities during the reduction of 4-nitrophenol and various other nitroaromatic compounds. Moreover, the catalytic activities of the HNTs@Fe3O4@AuPd nanocatalysts were tunable via adjusting the atomic ratio of AuPd during the synthesis. As compared with the monometallic nanocatalysts (HNTs@Fe3O4@Au and HNTs@Fe3O4@Pd, the bimetallic alloyed HNTs@Fe3O4@AuPd nanocatalysts exhibited excellent catalytic activities toward the reduction of 4-nitrophenol (4-NP to 4-aminophenol. Furthermore, the as-obtained HNTs@Fe3O4@AuPd can be recycled several times, while retaining its functionality due to the stability and magnetic separation property.

Balance functions from Au+Au, d+Au, and p+p collisions at root s(NN)=200 GeV

Czech Academy of Sciences Publication Activity Database

Aggarwal, M. M.; Ahammed, Z.; Alakhverdyants, A. V.; Alekseev, I.; Alford, J.; Anderson, B.D.; Arkhipkin, D.; Averichev, G. S.; Balewski, J.; Barnby, L. S.; Baumgart, S.; Beavis, D.R.; Bellwied, R.; Betancourt, M.J.; Betts, R. R.; Bhasin, A.; Bhati, A.K.; Bichsel, H.; Bielčík, Jaroslav; Bielčíková, Jana; Biritz, B.; Bland, L.C.; Bonner, B.E.; Bouchet, J.; Braidot, E.; Brandin, A.V.; Bridgeman, A.; Bruna, E.; Bueltmann, S.; Bunzarov, I.; Burton, T. P.; Cai, X.Z.; Caines, H.; Sanchez, M.C.D.; Catu, O.; Cebra, D.; Cendejas, R.; Cervantes, M.C.; Chajecki, Z.; Chaloupka, Petr; Chattopadhyay, S.; Chen, H.F.; Chen, J.H.; Chen, J.Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Choi, K.E.; Christie, W.; Chung, P.; Clarke, R.F.; Codrington, M.J.M.; Corliss, R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Leyva, A.D.; De Silva, L.C.; Debbe, R.R.; Dedovich, T. G.; Derevschikov, A.A.; de Souza, R.D.; Didenko, L.; Djawotho, P.; Dogra, S.M.; Dong, X.; Drachenberg, J.L.; Draper, J. E.; Dunlop, J.C.; Mazumdar, M.R.D.; Efimov, L.G.; Elhalhuli, E.; Elnimr, M.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Eun, L.; Evdokimov, O.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Fersch, R.G.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Gagliardi, C. A.; Gangaharan, D.R.; Ganti, M. S.; Garcia-Solis, E.J.; Geromitsos, A.; Geurts, F.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y.N.; Gordon, A.; Grebenyuk, O.; Grosnick, D.; Guertin, S.M.; Gupta, A.; Gupta, N.; Guryn, W.; Haag, B.; Hamed, A.; Han, L.X.; Harris, J.W.; Hays-Wehle, J.P.; Heinz, M.; Heppelmann, S.; Hirsch, A.; Hjort, E.; Hoffmann, A.M.; Hoffmann, G.W.; Hofman, D.J.; Horner, M.J.; Huang, B.; Huang, H.Z.; Humanic, T.J.; Huo, L.; Igo, G.; Jacobs, P.; Jacobs, W.W.; Jena, C.; Jin, F.; Jones, C.L.; Jones, P.G.; Joseph, J.; Judd, E.G.; Kabana, S.; Kajimoto, K.; Kang, K.; Kapitán, Jan; Kauder, K.; Keane, D.; Kechechyan, A.; Kettler, D.; Kikola, D.P.; Kiryluk, J.; Kisiel, A.; Klein, S.R.; Knospe, A.G.; Kocoloski, A.; Koetke, D.D.; Kollegger, T.; Konzer, J.; Koralt, I.; Koroleva, L.; Korsch, W.; Kotchenda, L.; Kushpil, Vasilij; Kravtsov, P.; Krueger, K.; Krus, M.; Kumar, L.; Kurnadi, P.; Lamont, M.A.C.; Landgraf, J.M.; LaPointe, S. (ed.); Lauret, J.; Lebedev, A.; Lednický, Richard; Lee, Ch.; Lee, J.H.; Leight, W.; LeVine, M.J.; Li, C.; Li, L.; Li, N.; Li, W.; Li, X.; Li, Y.; Li, Z.M.; Lin, G.; Lindenbaum, S.J.; Lisa, M.A.; Liu, F.; Liu, H.; Liu, J.; Ljubicic, T.; Llope, W.J.; Longacre, R.S.; Love, W.A.; Lu, Y.; Luo, X.; Ma, G.L.; Ma, Y.G.; Mahapatra, D. P.; Majka, R.; Mall, O.I.; Mangotra, L.K.; Manweiler, R.; Margetis, S.; Markert, C.; Masui, H.; Matis, H.S.; Matulenko, Yu.A.; McDonald, D.; McShane, T.S.; Meschanin, A.; Milner, R.; Minaev, N.G.; Mioduszewski, S.; Mischke, A.; Mitrovski, M.K.; Mohanty, B.; Mondal, M.M.; Morozov, B.; Morozov, D.A.; Munhoz, M. G.; Nandi, B.K.; Nattrass, C.; Nayak, T. K.; Nelson, J.M.; Netrakanti, P.K.; Ng, M.J.; Nogach, L.V.; Nurushev, S.B.; Odyniec, G.; Ogawa, A.; Okorokov, V.; Oldag, E.W.; Olson, D.; Pachr, M.; Page, B.S.; Pal, S.K.; Pandit, Y.; Panebratsev, Yu.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S.C.; Pile, P.; Planinic, M.; Ploskon, M.A.; Pluta, J.; Plyku, D.; Poljak, N.; Poskanzer, A.M.; Potukuchi, B.V.K.S.; Powell, C.B.; Prindle, D.; Pruneau, C.; Pruthi, N.K.; Pujahari, P.R.; Putschke, J.; Raniwala, R.; Raniwala, S.; Ray, R.L.; Redwine, R.; Reed, R.; Ritter, H.G.; Roberts, J.B.; Rogachevskiy, O.V.; Romero, J.L.; Rose, A.; Roy, C.; Ruan, L.; Sahoo, R.; Sakai, S.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sangaline, E.; Schambach, J.; Scharenberg, R.P.; Schmitz, N.; Schuster, T.R.; Seele, J.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shahaliev, E.; Shao, M.; Sharma, M.; Shi, S.S.; Sichtermann, E.P.; Simon, F.; Singaraju, R.N.; Skoby, M.J.; Smirnov, N.; Sorensen, P.; Sowinski, J.; Spinka, H.M.; Srivastava, B.; Stanislaus, T.D.S.; Staszak, D.; Stevens, J.R.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M.C.; Subba, N.L.; Šumbera, Michal; Sun, X.M.; Sun, Y.; Sun, Z.; Surrow, B.; Svirida, D.N.; Symons, T.J.M.; de Toledo, A. S.; Takahashi, J.; Tang, A.H.; Tang, Z.; Tarini, L.H.; Tarnowsky, T.; Thein, D.; Thomas, J.H.; Tian, J.; Timmins, A.R.; Timoshenko, S.; Tlustý, David; Tokarev, M. V.; Trainor, T.A.; Tram, V.N.; Trentalange, S.; Tribble, R. E.; Tsai, O.D.; Ulery, J.; Ullrich, T.; Underwood, D.G.; Van Buren, G.; van Leeuwen, M.; van Nieuwenhuizen, G.; Vanfossen, J.A.; Varma, R.; Vasconcelos, G.M.S.; Vasiliev, A. N.; Videbaek, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S.A.; Wada, M.; Walker, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J.S.; Wang, Q.; Wang, X.L.; Wang, Y.; Webb, G.; Westfall, G.D.; Whitten, C.; Wieman, H.; Wissink, S.W.; Witt, R.; Wu, Y.F.; Xie, W.; Xu, N.; Xu, Q.H.; Xu, W.; Xu, Y.; Xu, Z.; Xue, L.; Yang, Y.; Yepes, P.; Yip, K.; Yoo, I.K.; Yue, Q.; Zawisza, M.; Zbroszczyk, H.; Zhan, W.; Zhang, J.B.; Zhang, S.; Zhang, W.M.; Zhang, X.P.; Zhang, Y.; Zhang, Z.P.; Zhao, J.; Zhong, C.; Zhou, J.; Zhou, W.; Zhu, X.; Zhu, Y.H.; Zoulkarneev, R.; Zoulkarneeva, Y.

2010-01-01

Roč. 82, č. 2 (2010), 024905/1-024905/16 ISSN 0556-2813 Institutional research plan: CEZ:AV0Z10480505; CEZ:AV0Z10100502 Keywords : HEAVY-ION COLLISIONS * AU-AU COLLISIONS * TIME PROJECTION CHAMBER Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 3.416, year: 2010

Glow-peak stability in 6LiF:Mg, Ti (TLD-600) exposed to a Fe-ion beam

International Nuclear Information System (INIS)

Yasuda, Hiroshi

2001-01-01

The stability of glow peaks in 6 LiF:Mg, Ti (TLD-600) exposed to a high-energy Fe-ion beam was examined in comparison to 137 Cs γ-ray irradiation under changing annealing conditions. The peak areas induced by the Fe ions were much smaller than those by γ-rays. The sizes and positions of peaks 3-5 in Fe-ion irradiated samples were hardly changed after post-annealing at 100 deg C x 30 min, regardless of the pre-annealing conditions (fast quenching or subsequent pre-annealing at 100 deg C x 2 h). Whereas, the peaks in γ-ray irradiated samples were notably affected by post-annealing; the peak positions and peak-area sizes changed in different ways depending on the pre-annealing conditions. The effects of post-annealing on peak 6 were identical for Fe ions and γ-rays. These facts suggest that peaks 3-5 in TLD-600 comprised both stable and unstable luminescent centers, and that the latter part would be easily depleted in highly dense ionization. (author)

Fabrication of γ-Fe2O3 Nanoparticles by Solid-State Thermolysis of a Metal-Organic Framework, MIL-100(Fe, for Heavy Metal Ions Removal

Directory of Open Access Journals (Sweden)

Shengtao Hei

2014-01-01

Full Text Available Porous γ-Fe2O3 nanoparticles were prepared via a solid-state conversion process of a mesoporous iron(III carboxylate crystal, MIL-100(Fe. First, the MIL-100(Fe crystal that served as the template of the metal oxide was synthesized by a low-temperature (<100°C synthesis route. Subsequently, the porous γ-Fe2O3 nanoparticles were fabricated by facile thermolysis of the MIL-100(Fe powders via a two-step calcination treatment. The obtained γ-Fe2O3 was characterized by X-ray diffraction (XRD, N2 adsorption, X-ray photoelectron spectroscopy (XPS, and scanning electron microscopy (SEM techniques, and then used as an adsorbent for heavy metal ions removal in water treatment. This study illustrates that the metal-organic frameworks may be suitable precursors for the fabrication of metal oxides nanomaterials with large specific surface area, and the prepared porous γ-Fe2O3 exhibits a superior adsorption performance for As(V and As(III ions removal in water treatment.

Effect of argon ion etching on the magnetic properties of FeCoB films

Energy Technology Data Exchange (ETDEWEB)

Zhu, Junwei; Zhou, Kan; Yang, Yi; Tang, Dongming; Zhang, Baoshan, E-mail: malab@nju.edu.cn; Lu, Mu; Lu, Huaixian

2015-01-15

In this paper, a new method to modify Ta underlayers by an argon ion etching technology is introduced. Surface roughness of Ta underlayers, as well as soft magnetic properties of post-deposited FeCoB films can be improved by applying a proper ion etching process. The reduction of magnetic coercivity of FeCoB films deposited on the modified Ta underlayers is attributed to the improvement of interfacial roughness, which can reduce magnetic ripples in magnetic films. The microwave damping linewidth of magnetic films is also found to be related to the interfacial roughness. Ta underlayers modified by the ion etching can reduce the influence of two-magnon scattering effect, and thus tune microwave properties of magnetic films. All the results prove that argon ion etching is an effective way to tailor magnetic properties of magnetic films. - Highlights: • We believe that our method to tune the magnetic film properties will be interesting for general readers of Journal of Magnetism and Magnetic Materials. • In the paper, argon ion etching is applied to the Ta underlayer before the FeCoB film is deposited on it. • The modified interface roughness has effectively improved the magnetic properties, including the static magnetic and microwave performance. • The method is valuable for other underlayer/magnetic film systems.

Effect of ion irradiation on surface morphology and superconductivity of BaFe{sub 2}(As{sub 1−x}P{sub x}){sub 2} films

Energy Technology Data Exchange (ETDEWEB)

Daghero, D., E-mail: dario.daghero@polito.it [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Tortello, M. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Gozzelino, L. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Torino, 10125 Torino (Italy); Gonnelli, R.S. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Hatano, T.; Kawaguchi, T.; Ikuta, H. [Department of Crystalline Materials Science, Nagoya University, Nagoya 464-8603 (Japan)

2017-02-15

Highlights: • Epitaxial films of BaFe{sub 2}(As,P){sub 2} at optimal doping on MgO substrate have been irradiated by 250 MeV Au ions with different fluences. • Irradiation induces a partial relaxation of the in-plane tensile stress typical of the pristine films. • The residual resistivity increases less than linearly with fluence, tending to saturate; the overall increase is about 60%, but the critical temperature decreases by only 2%. • These results indicate that the substrate and the reduced dimensionality of the films (as compared to the case of single crystals) play an important role in their response to irradiation. - Abstract: We have irradiated epitaxial thin films of BaFe{sub 2}(As{sub 1−x}P{sub x}){sub 2} with x ≃ 0.2 (optimal doping) with Au ions having an energy of 250 MeV. We have used two different fluences, Φ{sub 1} = 2.4 × 10{sup 11} cm{sup −2} and Φ{sub 2} = 7.3 × 10{sup 11} cm{sup −2}, and we have studied the effects of irradiation on the surface morphology, on the resistivity and on the critical temperature. We have found that irradiation progressively destroys the very clear and interconnected growth terraces typical of the pristine surface, leading first to their smoothening – accompanied by the appearance of localized defects – and then to a completely disordered surface. The residual resistivity increases by almost 60%, but the critical temperature decreases very little (i.e. by about 2%) on going from the pristine film to the most irradiated one. The possible role of the substrate in these results is discussed.

Freely migrating defects in ion-irradiated Cu3Au

International Nuclear Information System (INIS)

Wei, L.C.; Lang, E.; Flynn, C.P.; Averback, R.S.

1999-01-01

The efficiency of producing freely migrating vacancy defects in irradiated Cu 3 Au was examined using electrical resistivity measurements of radiation-induced ordering on highly perfect single-crystal films. Relative efficiencies for He, Ne, and Ar bombardments at different ion energy and specimen temperature were obtained. The ratio of the efficiencies of 0.6 MeV Ne to He increased with temperature from ∼0.25 at 340 K to a saturation value of ∼0.40 at 520 K. For Ar and He, the ratio increased from ∼0.11 at 360 K to ∼0.18 at 540 K. Estimates indicate that about half of all defects created in cascades are freely migrating. copyright 1999 American Institute of Physics

Swift heavy ion induced de wetting of metal oxide thin films on silicon

International Nuclear Information System (INIS)

Bolse, T.; Paulus, H.; Bolse, W.

2006-01-01

We have observed that thin oxide coatings (NiO, Fe 2 O 3 ) tend to dewet their Si substrate when being bombarded with swift heavy ions (350-600 MeV Au ions) even though the irradiation was carried out about 80 K and hence, the films never reached their melting point. Scanning electron and atomic force microscopy reveal a surprising similarity of the dewetting morphologies with those observed for molten polymer films on Si, which have recently been reported by others [S. Herminghaus, K. Jakobs, K. Mecke, J. Bischof, A. Fery, M. Ibn-Elhaj, S. Schlagowsky, Science 282 (1998) 916; R. Seemann, S. Herminghaus, K. Jacobs, J. Phys.: Condens. Matter 13 (2001) 4925]. Like in that cases also here heterogeneous and homogeneous hole nucleation could be identified. Heterogeneous nucleation is less pronounced in Fe 2 O 3 /Si than in NiO/Si. The occurrence of spinodal-like dewetting cannot be detected unambiguously. The dewetting kinetics were determined by means of Rutherford backscattering spectroscopy and found to slightly differ for the two compounds. The dewetting kinetics as well as the final dewetting pattern strongly depend on the initial film thicknesses. No dewetting occurs for film thicknesses above about 150 nm, while for very small thicknesses below about 40 nm the film decays into nm-sized spherical droplets. At intermediate film thicknesses percolated networks of small oxide bridges are formed

Monodisperse porous LiFePO4/C microspheres derived by microwave-assisted hydrothermal process combined with carbothermal reduction for high power lithium-ion batteries

Science.gov (United States)

Chen, Rongrong; Wu, Yixiong; Kong, Xiang Yang

2014-07-01

A microwave-assisted hydrothermal approach combined with carbothermal reduction has been developed to synthesize monodisperse porous LiFePO4/C microspheres, which possess the diameter range of 1.0-1.5 μm, high tap density of ∼1.3 g cm-3, and mesoporous characteristic with Brunauer-Emmett-Teller (BET) surface area of 30.6 m2 g-1. The obtained microspheres show meatball-like morphology aggregated by the carbon-coated LiFePO4 nanoparticles. The electrochemical impedance spectra (EIS) results indicate that carbon coating can effectively enhance both of the electronic and ionic conductivities for LiFePO4/C microspheres. The Li-ion diffusion coefficient of the LiFePO4/C microspheres calculated from the cyclic voltammetry (CV) curves is ∼6.25 × 10-9 cm2 s-1. The electrochemical performance can achieve about 100 and 90 mAh g-1 at 5C and 10C charge/discharge rates, respectively. As cathode material, the as-prepared LiFePO4/C microspheres show excellent rate capability and cycle stability, promising for high power lithium-ion batteries.

Size effect in the spin glass magnetization of thin AuFe films as studied by polarized neutron reflectometry.

Science.gov (United States)

Saoudi, M; Fritzsche, H; Nieuwenhuys, G J; Hesselberth, M B S

2008-02-08

We used polarized neutron reflectometry to determine the temperature dependence of the magnetization of thin AuFe films with 3% Fe concentration. We performed the measurements in a large magnetic field of 6 T in a temperature range from 295 to 2 K. For the films in the thickness range from 500 to 20 nm we observed a Brillouin-type behavior from 295 K down to 50 K and a constant magnetization of about 0.9 micro(B) per Fe atom below 30 K. However, for the 10 nm thick film we observed a Brillouin-type behavior down to 20 K and a constant magnetization of about 1.3 micro(B) per Fe atom below 20 K. These experiments are the first to show a finite-size effect in the magnetization of single spin-glass films in large magnetic fields. Furthermore, the ability to measure the deviation from the paramagnetic behavior enables us to prove the existence of the spin-glass state where other methods relying on a cusp-type behavior fail.

THE INFLUENCES OF Fe(III ION and Fe(OH3 COLLOID ON THE PHOTODEGRADATION of p-CHLOROPHENOL CATALYZED BY TiO2

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Endang Tri Wahyuni

2010-06-01

Full Text Available The influences of ionic Fe(III and colloidal Fe(OH3 on the effectiveness of p-chlorophenol photodegradation catalyzed by TiO2 has been studied. Photodegradation was carried out in a batch system by irradiating a suspension of TiO2, p-chlorophenol, and Fe(III as ionic or colloidal forms, using UV lamp for a period of time accompanied by magnetic stirring. Concentration of photodegraded p-chlorophenol was calculated by subtracting the initial concentration with that of undegraded p-chlorophenol. Concentration of undegraded p-chlorophenol was determined by gas chromatography. In this study, TiO2 mass and the photodegradation time were optimized. The influences of concentration of Fe(III solution, mass of Fe(OH3, and pH of the solution have also been systematically studied. The research results showed that the presence of Fe(III ions improved the effectiveness of photocatalytical degradation of p-chlorophenol, which was proportional to the concentrations of Fe(III ion. In contrast, the increasing mass of Fe(OH3 led to a decrease in the degree of p-chlorophenol photodegradation. Furthermore, it was observed that increasing pH of the solution resulted in a decrease in the photodegradation of p-chlorophenol. This phenomena may be due to the different species of TiO2 available at the surface of photocatalyst and of ionic Fe(III and colloidal Fe(OH3 in the solution resulted from the pH alteration. The highest photodegradation degree, ca. 80 % was obtained when 20 mg of TiO2 was applied in the photodegradation of 50 mL of 100 ppm p-chlorophenol solution in the presence of 100 ppm Fe3+ irradiated by UV-light for 25 hours.    Keywords: p-chlorophenol photodegradation, TiO2, Fe(III species

Thiol-PEG-carboxyl-stabilized Fe2O3/Au nanoparticles targeted to CD105: Synthesis, characterization and application in MR imaging of tumor angiogenesis

International Nuclear Information System (INIS)

Zhang, Song; Gong, Mingfu; Zhang, Dong; Yang, Hua; Gao, Fabao; Zou, Liguang

2014-01-01

Objective: To detect tumor angiogenesis in tumor-bearing mice using thiol-PEG-carboxyl-stabilized Fe 2 O 3 /Au nanoparticles targeted to CD105 on magnetic resonance imaging (MRI). Methods: Fe 2 O 3 /Au nanoparticles (hybrids) were prepared by reducing Au 3+ on the surface of Fe 2 O 3 nanoparticles. Hybrids were stabilized with thiol-PEG-carboxyl via the Au–S covalent bond, and further conjugated with anti-CD105 antibodies through amide linkages. Characteristics of the hybrid-PEG-CD105 nanoparticles were evaluated. Using these nanoparticles, the labeling specificity of human umbilical vein endothelial cells (HUVECs) was evaluated in vitro. MRI T2*-weighted images were obtained at different time points after intravenous administration of the hybrid-PEG-CD105 nanoparticles in the tumor-bearing mice. After MR imaging, the breast cancer xenografts were immediately resected for immunohistochemistry staining and Prussian blue staining to measure the tumor microvessel density (MVD) and evaluate the labeling of blood microvessels by the hybrid-PEG-CD105 nanoparticles in vivo. Results: The mean diameter of the hybrid-PEG-CD105 nanoparticles was 56.6 ± 8.0 nm, as measured by transmission electron microscopy (TEM). Immune activity of the hybrid-PEG-CD105 nanoparticles was 53% of that of the anti-CD105 antibody, as detected by enzyme-linked immunosorbent assay (ELISA). The specific binding of HUVECs with the hybrid-PEG-CD105 nanoparticles was proved by immunostaining and Prussian blue staining in vitro. For breast cancer xenografts, the combination of the hybrid-PEG-CD105 nanoparticles with blood microvessels was detectable by MRI after 60 min administration of the contrast agent. The T2* relative signal intensity (SI R ) was positively correlated with the tumor MVD (R 2 = 0.8972). Conclusion: Anti-CD105 antibody-coupled, thiol-PEG-carboxyl-stabilized core–shell Fe 2 O 3 /Au nanoparticles can efficiently target CD105 expressed by HUVECs. Furthermore, the hybrid-PEG-CD105

Visible-light promoted catalytic activity of dumbbell-like Au nanorods supported on graphene/TiO2 sheets towards hydrogenation reaction

Science.gov (United States)

Dai, Yunqian; Zhu, Mingyun; Wang, Xiaotian; Wu, Yanan; Huang, Chengqian; Fu, Wanlin; Meng, Xiangyu; Sun, Yueming

2018-06-01

In this work, the rationally-designed sharp corners on Au nanorods tremendously improved the catalytic activity, particularly in the presence of visible light irradiation, towards the hydrogenation of 4-nitrophenol to 4-aminophenol. A strikingly increased rate constant of 50.6 g‑1 s‑1 L was achieved in M-Au-3, which was 41.8 times higher than that of parent Au nanorods under dark conditions. The enhanced activities were proportional to the extent of the protruding sharp corners. Furthermore, remarkably enhanced activities were achieved in novel ternary Au/RGO/TiO2 sheets, which were endowed with a 52.0 times higher rate constant than that of straight Au nanorods. These remarkably enhanced activities were even higher than those of previously reported 3–5 nm Au and 3 nm Pt nanoparticles. It was systematically observed that there are three aspects to the synergistic effects between Au and RGO sheets: (i) electron transfer from RGO to Au, (ii) a high concentration of p-nitrophenol close to dumbbell-like Au nanorods on RGO sheets, and (iii) increased local reaction temperature from the photothermal effect of both dumbbell-like Au nanorods and RGO sheets.

Atomistic Insights into FeF3 Nanosheet: An Ultrahigh-Rate and Long-Life Cathode Material for Li-Ion Batteries.

Science.gov (United States)

Yang, Zhenhua; Zhao, Shu; Pan, Yanjun; Wang, Xianyou; Liu, Hanghui; Wang, Qun; Zhang, Zhijuan; Deng, Bei; Guo, Chunsheng; Shi, Xingqiang

2018-01-24

Iron fluoride with high operating voltage and theoretical energy density has been proposed as a high-performance cathode material for Li-ion batteries. However, the inertness of pristine bulk FeF 3 results in poor Li kinetics and cycling life. Developing nanosheet-based electrode materials is a feasible strategy to solve these problems. Herein, on the basis of first-principles calculations, first the stability of FeF 3 (012) nanosheet with different atomic terminations under different environmental conditions was systematically studied, then the Li-ion adsorption and diffusion kinetics were thoroughly probed, and finally the voltages for different Li concentrations were given. We found that F-terminated nanosheet is energetically favorable in a wide range of chemical potential, which provide a vehicle for lithium ion diffusion. Our Li-ion adsorption and diffusion kinetics study revealed that (1) the formation of Li dimer is the most preferred, (2) the Li diffusion energy barrier of Li dimer is lower than isolated Li atom (0.17 eV for Li dimer vs 0.22 eV for Li atom), and (3) the diffusion coefficient of Li is 1.06 × 10 -6 cm 2 ·s -1 , which is orders of magnitude greater than that of Li diffusion in bulk FeF 3 (10 -13 -10 -11 cm 2 ·s -1 ). Thus, FeF 3 nanosheet can act as an ultrahigh-rate cathode material for Li-ion batteries. More importantly, the calculated voltage and specific capacity of Li on the FeF 3 (012) nanosheet demonstrate that it has a much more stable voltage profile than bulk FeF 3 for a wide range of Li concentration. So, few layers FeF 3 nanosheet provides the desired long-life energy density in Li-ion batteries. These above findings in the current study shed new light on the design of ultrahigh-rate and long-life FeF 3 cathode material for Li-ion batteries.

Polypyrrole-coated α-LiFeO2 nanocomposite with enhanced electrochemical properties for lithium-ion batteries

International Nuclear Information System (INIS)

Zhang, Zhi-jia; Wang, Jia-Zhao; Chou, Shu-Lei; Liu, Hua-Kun; Ozawa, Kiyoshi; Li, Hui-jun

2013-01-01

A conducting α-LiFeO 2 -polypyrrole (α-LiFeO 2 -PPy) nanocomposite material was prepared by the chemical polymerization method as a cathode material for lithium-ion batteries. The porous α-LiFeO 2 was prepared via the microwave hydrothermal method and a post-annealing. The X-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy measurements showed that the α-LiFeO 2 nanoparticles were coated with PPy. The polypyrrole coating improves the reversible capacity and cycling stability (104 mAh g −1 at 0.1C after 100 cycles) for lithium-ion batteries. Even at the high rate of 10C, the electrode showed more than 40% of the capacity at low rate (0.1C)

Anomolous, intensity dependent losses in Au(32+) beams

International Nuclear Information System (INIS)

Blaskiewicz, M.; Ahrens, L.; Calvani, H.

1997-01-01

The AGS Booster is a rapid cycling proton and heavy ion synchrotron. Anomolous, intensity dependent losses in Au(32+) beams have been observed in the AGS Booster. No collective signal is expected, or observed, but increasing the number of injected ions decreases the beam lifetime. The loss rates for Au(32+) are compared with those for Au(15+)

Metal-Organic Frameworks Triggered High-Efficiency Li storage in Fe-Based Polyhedral Nanorods for Lithium-ion Batteries