1
|
Gulec A, Goymen M. Treatment of class II malocclussion: A comparative study of the effects of twin-block and fatigue resistant device. Niger J Clin Pract 2019; 21:1557-1563. [PMID: 30560817 DOI: 10.4103/njcp.njcp_110_18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Aim This is a retrospective cephalometric study aimed to compare the treatment effects of Twin-Block (TB) appliance with The Forsus Fatigue Resistant Device (FRD) appliance in class II division I patients in a composite of peak and post peak growth of period time. Materials and Methods The experimental sample consisted of the lateral cephalograms of 40 patients who were treated with either TB appliance (n = 15), FRD (n = 15) or the untreated control ones. In treatment groups lateral cephalograms taken before therapy as initial records (T1) and at the completion of functional therapy (T2) were used. The control group comprised 10 children with untreated skeletal Class II malocclusions. The normality of distribution of continuous variables was tested by Shaphiro wilk test. Oneway ANOVA and LSD test in parametric; Kruskall Wallis and all pairwaise multible comparison tests in non-parametric samples were used for comparing differences among 3 groups. Results Cephalometric analysis revealed that both TB and FRD appliances stimulated mandibular growth (P < 0.05) and no restriction was seen in maxilla in both groups (P > 0.05). The unwanted mandibular proclination was seen more in FRD group (P ≤ 0.001). Soft tissue didn't imitate the hard tissue (P > 0.05). Conclusion FRD group produced skeletal effects as much as TB group in peak and post peak period of growth with still more mandibular incisor proclination.
Collapse
Affiliation(s)
- A Gulec
- Department of Orthodontics, Faculty of Dentistry, Gaziantep University, Gaziantep, Turkey
| | - M Goymen
- Department of Orthodontics, Faculty of Dentistry, Gaziantep University, Gaziantep, Turkey
| |
Collapse
|
2
|
Yu XX, Gulec A, Sherman Q, Cwalina KL, Scully JR, Perepezko JH, Voorhees PW, Marks LD. Nonequilibrium Solute Capture in Passivating Oxide Films. Phys Rev Lett 2018; 121:145701. [PMID: 30339439 DOI: 10.1103/physrevlett.121.145701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Indexed: 06/08/2023]
Abstract
We report experimental results on the composition and crystallography of oxides formed on NiCrMo alloys during both high-temperature oxidation and aqueous corrosion experiments. Detailed characterization using transmission electron microscopy and diffraction, aberration-corrected chemical analysis, and atom probe tomography shows unexpected combinations of composition and crystallography, far outside thermodynamic solubility limits. The results are explained using a theory for nonequilibrium solute capture that combines thermodynamic, kinetic, and density functional theory analyses. In this predictive nonequilibrium framework, the composition and crystallography are controlled by the rapidly moving interface. The theoretical framework explains the unusual combinations of composition and crystallography, which we predict will be common for many other systems in oxidation and corrosion, and other solid-state processes involving nonequilibrium moving interfaces.
Collapse
Affiliation(s)
- Xiao-Xiang Yu
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Ahmet Gulec
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Quentin Sherman
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Katie Lutton Cwalina
- Department of Materials Science and Engineering, University of Virginia, P.O. Box 400745, 395 McCormick Road, Charlottesville, Virginia 22904, USA
| | - John R Scully
- Department of Materials Science and Engineering, University of Virginia, P.O. Box 400745, 395 McCormick Road, Charlottesville, Virginia 22904, USA
| | - John H Perepezko
- Department of Materials Science and Engineering, University of Wisconsin-Madison, 1509 University Avenue, Madison, Wisconsin 53706, USA
| | - Peter W Voorhees
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Laurence D Marks
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| |
Collapse
|
3
|
|
4
|
Hassan A, Zhang X, Liu X, Rowland CE, Jawaid AM, Chattopadhyay S, Gulec A, Shamirian A, Zuo X, Klie RF, Schaller RD, Snee PT. Charge Carriers Modulate the Bonding of Semiconductor Nanoparticle Dopants As Revealed by Time-Resolved X-ray Spectroscopy. ACS Nano 2017; 11:10070-10076. [PMID: 28846841 DOI: 10.1021/acsnano.7b04414] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Understanding the electronic structure of doped semiconductors is essential to realize advancements in electronics and in the rational design of nanoscale devices. Reported here are the results of time-resolved X-ray absorption studies on copper-doped cadmium sulfide nanoparticles that provide an explicit description of the electronic dynamics of the dopants. The interaction of a dopant ion and an excess charge carrier is unambiguously observed via monitoring the oxidation state. The experimental data combined with DFT calculations demonstrate that dopant bonding to the host matrix is modulated by its interaction with charge carriers. Furthermore, the transient photoluminescence and the kinetics of dopant oxidation reveal the presence of two types of surface-bound ions that create midgap states.
Collapse
Affiliation(s)
| | | | | | - Clare E Rowland
- Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | | | | | | | | | | | | | - Richard D Schaller
- Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | | |
Collapse
|
5
|
Yu XX, Gulec A, Yoon A, Zuo JM, Voorhees PW, Marks LD. Direct Observation of "Pac-Man" Coarsening. Nano Lett 2017; 17:4661-4664. [PMID: 28700241 DOI: 10.1021/acs.nanolett.7b01137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report direct observation of a "Pac-Man" like coarsening mechanism of a self-supporting thin film of nickel oxide. The ultrathin film has an intrinsic morphological instability due to surface stress leading to the development of local thicker regions at step edges. Density functional theory calculations and continuum modeling of the elastic instability support the model for the process.
Collapse
Affiliation(s)
- X X Yu
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
| | - A Gulec
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
| | - A Yoon
- Department of Materials Science and Engineering, University of Illinois , Urbana-Champaign, Illinois 61801, United States
| | - J M Zuo
- Department of Materials Science and Engineering, University of Illinois , Urbana-Champaign, Illinois 61801, United States
| | - P W Voorhees
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
| | - L D Marks
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
| |
Collapse
|
6
|
Liu S, Tan JM, Gulec A, Crosby LA, Drake TL, Schweitzer NM, Delferro M, Marks LD, Marks TJ, Stair PC. Stabilizing Single-Atom and Small-Domain Platinum via Combining Organometallic Chemisorption and Atomic Layer Deposition. Organometallics 2017. [DOI: 10.1021/acs.organomet.6b00869] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Shengsi Liu
- Department
of Chemistry and the Center for Catalysis and Surface Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - J. Miles Tan
- Department
of Chemistry and the Center for Catalysis and Surface Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Ahmet Gulec
- Department
of Materials Science and Engineering and the Center for Catalysis
and Surface Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Lawrence A. Crosby
- Department
of Materials Science and Engineering and the Center for Catalysis
and Surface Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Tasha L. Drake
- Department
of Chemistry and the Center for Catalysis and Surface Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Neil M. Schweitzer
- Department
of Chemical and Biological Engineering and the Center for Catalysis
and Surface Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Massimiliano Delferro
- Department
of Chemistry and the Center for Catalysis and Surface Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Laurence D. Marks
- Department
of Materials Science and Engineering and the Center for Catalysis
and Surface Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Tobin J. Marks
- Department
of Chemistry and the Center for Catalysis and Surface Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Peter C. Stair
- Department
of Chemistry and the Center for Catalysis and Surface Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
| |
Collapse
|
7
|
Liu S, Tan JM, Gulec A, Schweitzer NM, Delferro M, Marks LD, Stair PC, Marks TJ. Direct Synthesis of Low-Coordinate Pd Catalysts Supported on SiO2 via Surface Organometallic Chemistry. ACS Catal 2016. [DOI: 10.1021/acscatal.6b02046] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shengsi Liu
- Department
of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - J. Miles Tan
- Department
of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Ahmet Gulec
- Department
of Materials Science and Engineering, Northwestern University, 2145 Sheridan
Road, Evanston, Illinois 60208-3113, United States
| | - Neil M. Schweitzer
- Department
of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois, 60208-3113, United States
| | - Massimiliano Delferro
- Department
of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Laurence D. Marks
- Department
of Materials Science and Engineering, Northwestern University, 2145 Sheridan
Road, Evanston, Illinois 60208-3113, United States
| | - Peter C. Stair
- Department
of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Tobin J. Marks
- Department
of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| |
Collapse
|
8
|
Gulec A, Yu X, Taylor M, Perepezko JH, Marks L. Direct observation of incommensurate structure in Mo 3Si. Acta Crystallogr A Found Adv 2016; 72:660-666. [PMID: 27809205 DOI: 10.1107/s2053273316012286] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 07/29/2016] [Indexed: 11/10/2022]
Abstract
Z-contrast imaging, electron diffraction, atom-probe tomography (APT) and density functional theory calculations were used to study the crystal structure of the Mo3Si phase which was previously reported to have an A15 crystal structure. The results showed that Mo3Si has an incommensurate crystal structure with a non-cubic unit cell. The small off-stoichiometry in composition of the sample which was revealed by APT and atomic resolution Z-contrast imaging suggested that site substitution caused the development of split atomic positions, disorder and vacancies.
Collapse
Affiliation(s)
- Ahmet Gulec
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, USA
| | - Xiaoxiang Yu
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, USA
| | - Matthew Taylor
- Department of Materials Science and Engineering, University of Wisconsin-Madison, 1509 University Avenue, Madison, Wisconsin 53706, USA
| | - John H Perepezko
- Department of Materials Science and Engineering, University of Wisconsin-Madison, 1509 University Avenue, Madison, Wisconsin 53706, USA
| | - Laurence Marks
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, USA
| |
Collapse
|
9
|
Ding K, Gulec A, Johnson AM, Drake TL, Wu W, Lin Y, Weitz E, Marks LD, Stair PC. Highly Efficient Activation, Regeneration, and Active Site Identification of Oxide-Based Olefin Metathesis Catalysts. ACS Catal 2016. [DOI: 10.1021/acscatal.6b00098] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kunlun Ding
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Ahmet Gulec
- Department
of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Alexis M. Johnson
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Tasha L. Drake
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Weiqiang Wu
- Center
for Catalysis and Surface Science, Northwestern University, Evanston, Illinois 60208, United States
| | - Yuyuan Lin
- Department
of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Eric Weitz
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Laurence D. Marks
- Department
of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Peter C. Stair
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Argonne, Illinois, 60439 United States
| |
Collapse
|
10
|
Klie RF, Gulec A, Guo Z, Paulauskas T, Qiao Q, Tao R, Wang C, Low KB, Nicholls AW, Phillips PJ. The new JEOL JEM-ARM200CF at the University of Illinois at Chicago. Crystal Research and Technology 2016. [DOI: 10.1002/crat.201600162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
11
|
Gulec A, Phelan D, Leighton C, Klie RF. Simultaneous First-Order Valence and Oxygen Vacancy Order/Disorder Transitions in (Pr0.85Y0.15)0.7Ca0.3CoO3-δ via Analytical Transmission Electron Microscopy. ACS Nano 2016; 10:938-947. [PMID: 26592896 DOI: 10.1021/acsnano.5b06067] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Perovskite cobaltites have been studied for years as some of the few solids to exhibit thermally driven spin-state crossovers. The unanticipated first-order spin and electronic transitions recently discovered in Pr-based cobaltites are notably different from these conventional crossovers, and are understood in terms of a unique valence transition. In essence, the Pr valence is thought to spontaneously shift from 3+ toward 4+ on cooling, driving subsequent transitions in Co valence and electronic/magnetic properties. Here, we apply temperature-dependent transmission electron microscopy and spectroscopy to study this phenomenon, for the first time with atomic spatial resolution, in the prototypical (Pr0.85Y0.15)0.70 Ca0.30CoO3-δ. In addition to the direct spectroscopic observation of charge transfer between Pr and Co at the 165 K transition (on both the Pr and O edges), we also find a simultaneous order/disorder transition associated with O vacancies. Remarkably, the first-order valence change drives a transition between ordered and random O vacancies, at constant O vacancy density, demonstrating reversible crystallization of such vacancies even at cryogenic temperatures.
Collapse
Affiliation(s)
- Ahmet Gulec
- Department of Physics, University of Illinois at Chicago , Chicago, Illinois 60607, United States
| | - Daniel Phelan
- Department of Chemical Engineering and Materials Science, University of Minnesota , Minneapolis, Minnesota 55455, United States
- Materials Science Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Chris Leighton
- Department of Chemical Engineering and Materials Science, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Robert F Klie
- Department of Physics, University of Illinois at Chicago , Chicago, Illinois 60607, United States
| |
Collapse
|
12
|
Akyuz T, Akyuz S, Gulec A. Elemental and spectroscopic characterization of plasters from Fatih Mosque-Istanbul (Turkey) by combined micro-Raman, FTIR and EDXRF techniques. Spectrochim Acta A Mol Biomol Spectrosc 2015; 149:744-750. [PMID: 25989612 DOI: 10.1016/j.saa.2015.05.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 04/22/2015] [Accepted: 05/04/2015] [Indexed: 06/04/2023]
Abstract
The characterization of the plasters and coloring agents of the wall paintings of Fatih Mosque have been performed using combined micro-Raman, FTIR and EDXRF techniques. The investigations show that the plaster used on the walls has mixed gypsum-lime binders. Cinnabar {HgS}, lead red {Pb3O4} and hematite {α-Fe2O3} were identified in the red surfaces. Blue color is attributed to ultramarine blue {Na8-10Al6Si6O24S2-4}. Green color is assigned to mixtures of green earth, copper phthalocyanine {Cu(C32Cl16N8)} and brochantite {CuSO4·3Cu(OH)2}. Strontium yellow {SrCrO4} and zinc white {ZnO} were also used to ensure the color tone. The results provide a basis for future restoration of wall paints.
Collapse
Affiliation(s)
- Tanil Akyuz
- Physics Department, Science and Letters Faculty, Istanbul Kultur University, Atakoy Campus, Bakirkoy 34156, Istanbul, Turkey
| | - Sevim Akyuz
- Physics Department, Science and Letters Faculty, Istanbul Kultur University, Atakoy Campus, Bakirkoy 34156, Istanbul, Turkey.
| | - Ahmet Gulec
- Istanbul Metropolitan Municipality, Directorate of Conservation Implementation and Supervision (IBB-KUDEB), Fatih, Istanbul, Turkey
| |
Collapse
|
13
|
Ding K, Gulec A, Johnson AM, Schweitzer NM, Stucky GD, Marks LD, Stair PC. Identification of active sites in CO oxidation and water-gas shift over supported Pt catalysts. Science 2015; 350:189-92. [DOI: 10.1126/science.aac6368] [Citation(s) in RCA: 711] [Impact Index Per Article: 79.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Accepted: 08/19/2015] [Indexed: 01/22/2023]
|
14
|
Chen H, Qiao Q, Marshall MSJ, Georgescu AB, Gulec A, Phillips PJ, Klie RF, Walker FJ, Ahn CH, Ismail-Beigi S. Reversible modulation of orbital occupations via an interface-induced polar state in metallic manganites. Nano Lett 2014; 14:4965-4970. [PMID: 25140410 DOI: 10.1021/nl501209p] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The breaking of orbital degeneracy on a transition metal cation and the resulting unequal electronic occupations of these orbitals provide a powerful lever over electron density and spin ordering in metal oxides. Here, we use ab initio calculations to show that reversibly modulating the orbital populations on Mn atoms can be achieved at ferroelectric/manganite interfaces by the presence of ferroelectric polarization on the nanoscale. The change in orbital occupation can be as large as 10%, greatly exceeding that of bulk manganites. This reversible orbital splitting is in large part controlled by the propagation of ferroelectric polar displacements into the interfacial region, a structural motif absent in the bulk and unique to the interface. We use epitaxial thin film growth and scanning transmission electron microscopy to verify this key interfacial polar distortion and discuss the potential of reversible control of orbital polarization via nanoscale ferroelectrics.
Collapse
Affiliation(s)
- Hanghui Chen
- Department of Physics and ‡Department of Applied Physics and Applied Mathematics, Columbia University , New York, New York 10027, United States
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Pirbudak L, Karakurum G, Oner U, Gulec A, Karadasli H. Epidural corticosteroid injection and amitriptyline for the treatment of chronic low back pain associated with radiculopathy. ACTA ACUST UNITED AC 2013. [DOI: 10.1163/156856903767650763] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
16
|
Klie RF, Gulec A, Guo Z, Paulauskas T, Qiao Q, Tao R, Wang C, Low KB, Nicholls AW, Phillips PJ. The new JEOL JEM-ARM200CF at the University of Illinois at Chicago. Crystal Research and Technology 2013. [DOI: 10.1002/crat.201300200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- R. F. Klie
- University of Illinois at Chicago; Chicago IL 60607 USA
| | - A. Gulec
- University of Illinois at Chicago; Chicago IL 60607 USA
| | - Z. Guo
- University of Illinois at Chicago; Chicago IL 60607 USA
| | - T. Paulauskas
- University of Illinois at Chicago; Chicago IL 60607 USA
| | - Q. Qiao
- University of Illinois at Chicago; Chicago IL 60607 USA
| | - R. Tao
- University of Illinois at Chicago; Chicago IL 60607 USA
| | - C. Wang
- University of Illinois at Chicago; Chicago IL 60607 USA
| | - K. B. Low
- University of Illinois at Chicago; Chicago IL 60607 USA
| | | | | |
Collapse
|
17
|
Klie RF, Qiao Q, Paulauskas T, Gulec A, Rebola A, Öğüt S, Prange MP, Idrobo JC, Pantelides ST, Kolesnik S, Dabrowski B, Ozdemir M, Boyraz C, Mazumdar D, Gupta A. Observations of Co4+ in a higher spin state and the increase in the Seebeck coefficient of thermoelectric Ca3Co4O9. Phys Rev Lett 2012; 108:196601. [PMID: 23003068 DOI: 10.1103/physrevlett.108.196601] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Indexed: 06/01/2023]
Abstract
Ca3Co4O9 has a unique structure that leads to exceptionally high thermoelectric transport. Here we report the achievement of a 27% increase in the room-temperature in-plane Seebeck coefficient of Ca3Co4O9 thin films. We combine aberration-corrected Z-contrast imaging, atomic-column resolved electron energy-loss spectroscopy, and density-functional calculations to show that the increase is caused by stacking faults with Co4+-ions in a higher spin state compared to that of bulk Ca3Co4O9. The higher Seebeck coefficient makes the Ca3Co4O9 system suitable for many high temperature waste-heat-recovery applications.
Collapse
Affiliation(s)
- R F Klie
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Akyuz S, Akyuz T, Emre G, Gulec A, Basaran S. Pigment analyses of a portrait and paint box of Turkish artist Feyhaman Duran (1886-1970): the EDXRF, FT-IR and micro Raman spectroscopic studies. Spectrochim Acta A Mol Biomol Spectrosc 2012; 89:74-81. [PMID: 22245940 DOI: 10.1016/j.saa.2011.12.046] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 12/02/2011] [Accepted: 12/21/2011] [Indexed: 05/31/2023]
Abstract
The samples obtained from nine different places of Ataturk portrait (oil on canvas, 86 cm×136 cm) by Feyhaman Duran (1886-1970), one of the famous Turkish painters of the 20th century, together with five pigment samples (two different white, two different yellow and blue), obtained as powders from artist's paint box, were analysed by EDXRF, FT-IR and micro-Raman spectroscopic methods, in order to characterise the pigments used by the artist. Informative Raman signals were not obtained from most of the samples of the portrait, due to huge fluorescence caused by the presence of impurities and organic materials in the samples, however the Raman spectrum of the sample from skin coloured part of the portrait and the pigment samples obtained from the paint box of the artist were found to be very informative to shed light on the determination of the pigments used. Analysis revealed the presences of chrome yellow (PbCrO4), strontium yellow (SrCrO4) and Cadmium yellow (CdS) as yellow, chromium oxides (Cr2O3 and Cr2O3·2H2O) as green, natural red ochre as red, brown ochre as brown and ivory black or bone black (C+Ca3(PO4)2) and manganese oxides (Mn2O3 and MnO2) as black pigments, in the composition of the Ataturk portrait. Lead white (2PbCO3·Pb(OH)2), calcite (CaCO3), barite (BaSO4), zinc white (ZnO) and titanium white (TiO2) were used as extenders to lighten the colours and/or as for ground level painting. Powder pigment samples, obtained from the paint box of artist, were found to be mixed pigments rather than pure ones.
Collapse
Affiliation(s)
- Sevim Akyuz
- Physics Department, Science and Letters Faculty, Istanbul Kultur University, Atakoy Campus, Bakirkoy 34156, Istanbul, Turkey.
| | | | | | | | | |
Collapse
|
19
|
Qiao Q, Gulec A, Paulauskas T, Kolesnik S, Dabrowski B, Ozdemir M, Boyraz C, Mazumdar D, Gupta A, Klie RF. Effect of substrate on the atomic structure and physical properties of thermoelectric Ca₃Co₄O₉ thin films. J Phys Condens Matter 2011; 23:305005. [PMID: 21719960 DOI: 10.1088/0953-8984/23/30/305005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The incommensurately layered cobalt oxide Ca(3)Co(4)O(9) exhibits an unusually high Seebeck coefficient as a polycrystalline bulk material, making it ideally suited for many high temperature thermoelectric applications. In this paper, we investigate properties of Ca(3)Co(4)O(9) thin films grown on cubic perovskite SrTiO(3), LaAlO(3), and (La(0.3)Sr(0.7))(Al(0.65)Ta(0.35))O(3) substrates and on hexagonal Al(2)O(3) (sapphire) substrates using the pulsed laser deposition technique. X-ray diffraction and transmission electron microscopy analysis indicate strain-free growth of films, irrespective of the substrate. However, depending on the lattice and symmetry mismatch, defect-free growth of the hexagonal CoO(2) layer is stabilized only after a critical thickness and, in general, we observe the formation of a stable Ca(2)CoO(3) buffer layer near the substrate-film interface. Beyond this critical thickness, a large concentration of CoO(2) stacking faults is observed, possibly due to weak interlayer interaction in this layered material. We propose that these stacking faults have a significant impact on the Seebeck coefficient and we report higher values in thinner Ca(3)Co(4)O(9) films due to additional phonon scattering sites, necessary for improved thermoelectric properties.
Collapse
Affiliation(s)
- Q Qiao
- Department of Physics, University of Illinois at Chicago, Chicago, IL, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Akyuz S, Akyuz T, Basaran S, Bolcal C, Gulec A. FT-IR and micro-Raman spectroscopic study of decorated potteries from VI and VII century BC, excavated in ancient Ainos – Turkey. J Mol Struct 2007. [DOI: 10.1016/j.molstruc.2006.12.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
21
|
Karakurum G, Pirbudak L, Oner U, Gulec A, Karadasli H, Satana T. Sympathetic blockade and amitriptyline in the treatment of reflex sympathetic dystrophy. Int J Clin Pract 2003; 57:585-7. [PMID: 14529058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/05/2023] Open
Abstract
We prospectively investigated the outcome of a combination therapy of oral amitriptyline and sympathetic ganglion blockade on 10 patients suffering from reflex sympathetic dystrophy of the upper extremity for at least three months. The efficacy of the treatment was evaluated by clinical examination, pain ratings on the visual analogue scale (VAS) and grip strength measurements using the Jamar dynamometer. The results were statistically analysed with Wilcoxon signed-ranks test for comparison of the before and after treatment grip strength measurements and with paired t-test for comparison of the mean of initial and consecutive pain ratings on the VAS. Values of p < 0.01 were considered to be statistically significant. Combination therapy proved beneficial in this particular patient population, which, as far as previously documented studies are concerned, would otherwise respond less favourably to a treatment consisting solely of sympathetic blockade.
Collapse
Affiliation(s)
- G Karakurum
- Departments of Orthopaedics, University of Gaziantep, Gaziantep, Turkey
| | | | | | | | | | | |
Collapse
|