Structural characterization of Zr-doped ZnO films deposited on quartz substrates by reactive radio frequency magnetron co-sputtering

Sung, Nark-Eon,Lee, Kug-Seung,Lee, Ik-Jae Elsevier 2018 THIN SOLID FILMS - Vol.651 No.-

<P><B>Abstract</B></P> <P>Zr-doped ZnO (Zn<SUB>1−<I>x</I> </SUB>Zr<SUB> <I>x</I> </SUB>O, 0 ≤ <I>x</I> ≤ 0.067; ZZO) thin films were grown at room temperature by reactive radio frequency co-sputtering on quartz substrates The ZZO films have a strong preferred orientation toward the c-axis but this orientation weakened as <I>x</I> increased. The size of crystallites of the ZZO films decreased and the surfaces of the ZZO films smoothened as <I>x</I> increased. The Zn atom were divalent and slightly affected only in the <I>c</I>-axis. Zn <I>K</I>-edge X-ray absorption near edge structure (XANES) spectra of the ZZO films show that the Zn atom were divalent and slightly affected only in the <I>c</I>-axis. The Zr atoms were tetravalent and their <I>K</I>-edge XANES spectra were slight different from that of ZrO<SUB>2</SUB>. Polarization-dependent Zn <I>K</I>-edge extended x-ray absorption fine-structure (EXAFS) spectra revealed that the local structural variation was stronger along the <I>c</I>-axis than along other axes. The Zn atom site was well replaced by Zr atom regardless of <I>x</I>. Average optical transmittance in the visible region was ≥90%, and as <I>x</I> increased, optical band gap increased and blue-shifted.</P> <P><B>Highlights</B></P> <P> <UL> <LI> ZZO film has a preferred orientation, but it is degraded as <I>x</I> increases. </LI> <LI> The local structural variation was stronger along the <I>c</I>-axis than along other axes. </LI> <LI> Zn and Zr <I>K</I>-edge XANES spectra clearly show the dependence on <I>x</I>. </LI> <LI> All films were flat and smooth and had optical transmittance ≥90%. </LI> <LI> The band gap blue-shifted as <I>x</I> increased. </LI> </UL> </P>

X-ray diffraction and X-ray absorption spectroscopic analyses for intercalative nanohybrids with low crystallinity

Park, D.H.,Yang, J.H.,Vinu, A.,Elzatahry, A.,Choy, J.H. Elsevier ; King Saud University 2016 Arabian journal of chemistry Vol.9 No.2

<P>Intercalation reactions can be achieved through ion-exchange, pillaring, and exfoliation-reassembling reactions to explore new intercalation compounds with desired electronic, electrochemical, and optical functions. Such intercalative nanohybrids with lamellar or porous structure have received much attention due to their potential applications such as catalysts, electrodes, selective adsorbents, stabilizing agents, and even drug delivery systems. In this review, we briefly introduce and highlight X-ray diffraction and X-ray absorption spectroscopy studies on the intercalative nanohybrids to understand their intracrystalline and electronic structures along with physicochemical functions. (C) 2015 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University.</P>

The effect of zinc and titanium on the structure of calcium-sodium phosphate based glass

Moss, R.M.,Neel, E.A.A.,Pickup, D.M.,Twyman, H.L.,Martin, R.A.,Henson, M.D.,Barney, E.R.,Hannon, A.C.,Knowles, J.C.,Newport, R.J. North-Holland 2010 Journal of non-crystalline solids Vol.356 No.25

An array of different structural probes has been used to define the effect of adding Zn and Ti to a sodium-calcium phosphate glass. X-ray absorption spectroscopy at the Zn K-edge suggests that the Zn atoms occupy mixed (4- and 6-fold) sites within the glass matrix. X-ray diffraction reveals a feature at 2.03A that develops with the addition of Zn and Ti and is consistent with Zn-O and Ti-O near-neighbour distances. Neutron diffraction is used to resolve two distinct P-O distances and highlights the decrease in P...P coordination number from 2.0 to 1.7 as the Ti metal concentration rises, which is attributed to the O/P fraction moving away from the metaphosphate value of 3.0 to 3.1 with the addition of Ti. Other correlations, such as those associated with CaO<SUB>x</SUB>and NaO<SUB>x</SUB>polyhedra, remain largely unaffected. These results suggest that the network forming P...P correlation is most disrupted, with the disorder parameter rising from 0.07 to 0.10A with the additional modifiers. Zn appears to be introduced into the network as a direct replacement for Ca and causes no structural variation over the composition range studied.

Mechanism for the stabilization/solidification of arsenic-contaminated soils with Portland cement and cement kiln dust

Yoon, I.H.,Moon, D.H.,Kim, K.W.,Lee, K.Y.,Lee, J.H.,Kim, M.G. Academic Press 2010 Journal of environmental management Vol.91 No.11

In this study, the mechanism for the stabilization/solidification (S/S) of arsenic (As)-contaminated soils with Portland cement (PC), and cement kiln dust (CKD) using 1 N HCl extraction fluid, X-ray powder diffraction (XRPD), X-ray absorption near edge structure (XANES) and Extended X-ray absorption fine structure (EXAFS) spectroscopy was investigated. The degree of As immobilization after stabilization was assessed using a 1 N HCl extraction on the basis of the Korean Standard Test (KST). After 1 day of curing with 30 wt% PC and 7 days of curing with 50 wt% CKD, the concentration of As leached from the amended soils was less than the Korean countermeasure standard (3 mg L<SUP>-1</SUP>). The As concentrations in the leachate treated with PC and CKD were significantly decreased at pH > 3, indicating that pH had a prevailing influence on As mobility. XRPD results indicated that calcium arsenite (Ca-As-O) and sodium calcium arsenate hydrate (NaCaAsO<SUB>4</SUB>.7.5H<SUB>2</SUB>O) were present in the PC- and CKD-treated slurries as the key phases responsible for As(III) and As(V) immobilization, respectively. The XANES spectroscopy confirmed that the As(III) and As(V) oxidation states of the PC and CKD slurry samples were consistent with the speciated forms in the crystals identified by XRPD. EXAFS spectroscopy showed As-Ca bonding in the As(III)-PC and As(III)-CKD slurries. The main mechanism for the immobilization of As-contaminated soils with PC and CKD was strongly associated with the bonding between As(III) or As(V) and Ca.

TEM 관련 이론해설 (4): 방사선의 종류와 물질에 의한 산란

이확주,Lee, Hwack-Joo 한국현미경학회 2003 Applied microscopy Vol.33 No.4

In this review, the sources and the characteristics of X-rays and electrons and their interactions with matters were described in terms of the atomic scattering factors. The geometrical diffraction conditions were taken into account in terms of Ewald spheres in reciprocal lattice spaces. The effects of the finite size of sources and detectors on diffractions were also considered. 물질의 구조 특성파악에 많이 사용되는 X-선과 전자선에 대한 소스 원을 살펴보고 물질과의 반응을 atomic scattering factor의 항으로 설명하였다. 물질과의 회절을 역 격자 공간에서의 Ewald sphere로 설명하고 유한 크기의 소스 파장과 검출기의 효과도 함께 고려하였다.

In-situ X-ray Analyses of Electrocatalysts for Electrochemical CO₂ Reduction Reaction

이지훈 한국공업화학회 2021 한국공업화학회 연구논문 초록집 Vol.2021 No.1

Preparation and Characterization of Suvarna Bhasma Parada Marit - Characterization of Suvarna Bhasma Parada Marit -

Kapil Thakur,Ramacharya Gudi,Mahesh Vahalia,Shekhar Shitut,Shailesh Nadkarni 대한약침학회 2017 Journal of pharmacopuncture Vol.20 No.1

Objectives: The goal of this study was to characterize Suvarna Bhasma Parada Marit by using the Ayurvedic test parameters, physico-chemical tests, and various instrumentation techniques. Methods: Suvarna Bhasma, an Ayurvedic formulation manufactured as per Bharat Bhaishajya Ratnakar 5/8357 (BBR), has been studied using various instrumentation techniques: X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), laser particle size distribution (PSD) analysis, fourier transform infrared spectroscopy (FT-IR), and atomic absorption spectroscopy (AAS), and physico-chemical parameters, such as the loss on drying (LOD), loss on ignition (LOI), and acid insoluble Ash (AIA) were determined. In addition, Ayurvedic tests, such as Rekhapurnatva (enterable in the furrows of the fingers), Varitaratwa (floatable over water), Nirdhoomta (smokeless), Dantagre Kach-Kach (gritty particle feeling between the teeth), were performed. Results: The XRD study showed Suvarna Bhasma to be crystalline in nature and to contain more than 98% gold. The mean size of the gold crystallites was less than 10 microns, and the morphology was globular and irregular. Suvarna Bhasma contains gold as its single and major element, with EDAX and FT-IR spectra showing that it is more than 98% pure gold. The moisture content (LOD) is less than 0.5%, the LOI is less than 2%, and the AIA is not less than 95%. The Ayurvedic tests, as specified above, helped to confirm the quality of Suvarna bhasma prepared as per the text reference (BBR). Conclusion: This chemical characterization of Suvarna Bhasma performed in this study by using modern instrumentation techniques will be helpful in understanding its pharmacological actions and will help in establishing quality protocols and specifications to substantiate the safety, efficacy & quality of Suvarna Bhasma.

Ferromagnetism in Chemically-synthesized Co-doped ZnO

샤런드라쿠마르,Y. J. Kim,B. H. Koo,최희규,이찬규,S. K. Sharma,M. Knobel,S. Gautam,K. H. Chae 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.3

We report room temperature ferromagnetism (RTFM) in Co-doped ZnO (Zn1−xCoxO; x = 0.01 − 0.05) powder synthesized using a co-precipitation method. Our magnetometry data reveal a weak FM behavior at RT in the range 0.01 < x < 0.05. FM by magnetic FM moment steadily decreases with increasing dopant. The O K-edge near-edge X-ray absorption fine structure (NEXAFS) spectra indicate that O vacancies increases with increasing Co concentration and that the sample with x ≥ 0.03 has more broadening at 535 and 540 eV, which may be due to the oxygen vacancies. Co in the ZnO host reveals a +2 oxidation state via the K edge NEXAFS spectra.

방사광 X-선을 이용한 리튬이온전지 소재의 실시간 구조 분석 연구

한다슬(Daseul Han),남경완(Kyung-Wan Nam) 한국세라믹학회 2019 세라미스트 Vol.22 No.4

The development of next-generation secondary batteries, including lithium-ion batteries (LIB), requires performance enhancements such as high energy/high power density, low cost, long life, and excellent safety. The discovery of new materials with such requirements is a challenging and time-consuming process with great difficulty. To pursue this challenging endeavor, it is pivotal to understand the structure and interface of electrode materials in a multiscale level at the atomic, molecular, macro-scale during charging / discharging. In this regard, various advanced material characterization tools, including the first-principle calculation, high-resolution electron microscopy, and synchrotronbased X-ray techniques, have been actively employed to understand the charge storage- and degradationmechanisms of various electrode materials. In this article, we introduce and review recent advances in in-situ synchrotron-based x-ray techniques to study electrode materials for LIBs during thermal degradation and charging/ discharging. We show that the fundamental understanding of the structure and interface of the battery materials gained through these advanced in-situ investigations provides valuable insight into designing next-generation electrode materials with significantly improved performance in terms of high energy/high power density, low cost, long life, and excellent safety.

Preparation and Characterization of Suvarna Bhasma Parada Marit - Characterization of Suvarna Bhasma Parada Marit -

Thakur, Kapil,Gudi, Ramacharya,Vahalia, Mahesh,Shitut, Shekhar,Nadkarni, Shailesh KOREAN PHARMACOPUNCTURE INSTITUTE 2017 Journal of pharmacopuncture Vol.20 No.1

Objectives: The goal of this study was to characterize Suvarna Bhasma Parada Marit by using the Ayurvedic test parameters, physico-chemical tests, and various instrumentation techniques. Methods: Suvarna Bhasma, an Ayurvedic formulation manufactured as per Bharat Bhaishajya Ratnakar 5/8357 (BBR), has been studied using various instrumentation techniques: X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), laser particle size distribution (PSD) analysis, fourier transform infrared spectroscopy (FT-IR), and atomic absorption spectroscopy (AAS), and physico-chemical parameters, such as the loss on drying (LOD), loss on ignition (LOI), and acid insoluble Ash (AIA) were determined. In addition, Ayurvedic tests, such as Rekhapurnatva (enterable in the furrows of the fingers), Varitaratwa (floatable over water), Nirdhoomta (smokeless), Dantagre Kach-Kach (gritty particle feeling between the teeth), were performed. Results: The XRD study showed Suvarna Bhasma to be crystalline in nature and to contain more than 98% gold. The mean size of the gold crystallites was less than 10 microns, and the morphology was globular and irregular. Suvarna Bhasma contains gold as its single and major element, with EDAX and FT-IR spectra showing that it is more than 98% pure gold. The moisture content (LOD) is less than 0.5%, the LOI is less than 2%, and the AIA is not less than 95%. The Ayurvedic tests, as specified above, helped to confirm the quality of Suvarna bhasma prepared as per the text reference (BBR). Conclusion: This chemical characterization of Suvarna Bhasma performed in this study by using modern instrumentation techniques will be helpful in understanding its pharmacological actions and will help in establishing quality protocols and specifications to substantiate the safety, efficacy & quality of Suvarna Bhasma.