Size-dependent vibronic coupling in α-Fe₂O₃

O'Neal, K. R.,Patete, J. M.,Chen, P.,Holinsworth, B. S.,Smith, J. M.,Lee, N.,Cheong, S.-W.,Wong, Stanislaus S.,Marques, C.,Aronson, M. C.,Musfeldt, J. L. American Institute of Physics 2014 The Journal of chemical physics Vol.141 No.4

<P>We report the discovery of finite length scale effects on vibronic coupling in nanoscale alpha-Fe2O3 as measured by the behavior of vibronically activated d-d on-site excitations of Fe3+ as a function of size and shape. An oscillator strength analysis reveals that the frequency of the coupled symmetry-breaking phonon changes with size, a crossover that we analyze in terms of increasing three-dimensional character to the displacement pattern. These findings demonstrate the flexibility of mixing processes in confined systems and suggest a strategy for both enhancing and controlling charge-lattice interactions in other materials. (C) 2014 AIP Publishing LLC.</P>

Multivariate Analysis of Laser-Induced Breakdown Spectroscopy Spectra of Soil Samples

Yang, Ningfang,Eash, Neal S.,Lee, Jaehoon,Martin, Madhavi Z.,Zhang, Yong-Seon,Walker, Forbes R.,Yang, Jae E. Lippincott Williams Wilkins, Inc. 2010 Soil science Vol.175 No.9

ABSTRACT: Laser-induced breakdown spectroscopy (LIBS) is a rapid quantitative analytical technique that can be used to determine the elemental composition of numerous sample matrices, and it has been successfully applied in many types of samples. However, for chemically and physically complex soil samples, its quantitative analytical ability is controversial. Multivariate analytical techniques have great potential for analyzing the complex LIBS spectra. To demonstrate the feasibility of LIBS as an alternative technique to quantitatively analyze soil samples, the univariate and the partial least square (PLS) techniques are used to analyze the LIBS spectra of 12 soil samples and to build calibration models predicting Cu and Zn concentrations. The results show that PLS can significantly improve the analytical results compared with the univariate technique. The normalized root mean square error (NRMSE) and r of the univariate models are 16.60% and 0.71 in calibration and 18.80% and 0.62 in prediction for Cu and 18.97% and 0.62 in calibration and 22.81% and 0.45 in prediction for Zn. For the PLS models using the spectral range 300 to 350 nm, the NRMSE and r are 1.94% and 0.99 for both Cu and Zn in calibration and 7.90% and 0.94 for Cu and 8.14% and 0.94 for Zn in prediction, respectively. Compared with the univariate technique, PLS improves the NRMSE 87.53% and 87.78% in calibration and 44.47% and 53.44% in prediction for Cu and Zn, respectively. The results indicate that PLS can improve the quantitative analytical ability of LIBS for soil sample analysis.

Frustration and Glasslike Character in RIn_1-<i>x</i>Mn_<i>x</i>O₃ (R = Tb, Dy, Gd)

Chen, Peng,Holinsworth, Brian S.,O’Neal, Kenneth R.,Luo, Xuan,Topping, Craig V.,Cheong, Sang W.,Singleton, John,Choi, Eun S.,Musfeldt, Janice L. American Chemical Society 2018 Inorganic Chemistry Vol.57 No.20

<P>We bring together <I>ac</I> susceptibility and <I>dc</I> magnetization to uncover the rich magnetic field-temperature behavior of a series of rare earth indium oxides, RInO<SUB>3</SUB> (R = Tb, Dy, and Gd). The degree of frustration is much larger than expected, particularly in TbInO<SUB>3</SUB>, and the ground states are glasslike with antiferromagnetic tendencies. The activation energy for spin reorientation is low. Chemical substitution with Mn<SUP>3+</SUP> ions to form TbIn<SUB>1-<I>x</I></SUB>Mn<SUB><I>x</I></SUB>O<SUB>3</SUB> (<I>x</I> ≤ 0.01) relieves much of the frustration that characterizes the parent compound and slightly enhances the short-range antiferromagnetic order. The phase diagrams developed from this work reveal the rich competition between spin orders and provide an opportunity to compare the dynamics in the RInO<SUB>3</SUB> and Mn-substituted systems. These structure-property relations may be useful for understanding magnetism in other geometrically frustrated multiferroics.</P><P>We combined <I>dc</I> magnetization and <I>ac</I> susceptibility to reveal the rich magnetic field-temperature phase diagrams of a series of rare earth indium oxides. These systems sport high degrees of frustration as described by the frustration index, <I>F</I>, as well as glasslike slow magnetic relaxation in combination with antiferromagnetic tendencies. Structure−composition−property investigations reveal that both the choice of rare earth center as well as introduction of a paramagnetic impurity like Mn<SUP>3+</SUP> can control frustration in this new class of geometrically frustrated multiferroics.</P> [FIG OMISSION]</BR>

Validation of Run-time Doppler Broadening in MONK with JEFF3.1

C. Dean,R. Perry,R. Neal,A. Kyrieleis 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23

A fast and adequate method of run-time Doppler broadening has been developed within the MONK Monte Carlo code to give cross sections at the temperature defined by the user. The method utilises Gauss Quadrature to broaden continuous energy cross-sections and is applied to data generated by NJOY at a base temperature. It was not believed to dramatically increase the run time of the Monte Carlo code. It is less accurate than methods in NJOY so error builds up as temperature increases. To prevent this error becoming significant, data at several temperatures are pre-generated via NJOY. This allows new raised base temperatures to be used, minimising any broadening error. This method functions within the resolved resonance range, with interpolation methods being applied in the unresolved range. For bound nuclides methods of temperature interpolation have been developed in the thermal region. A JEFF3.1 based nuclear data library has been created with the features necessary to apply these methods. This "BINGO" library was generated with a module called the BINGO Pre-processor, whilst application within the MONK code required development of the "BINGO Collision Processor". The method, pre- and collision processors and library have been validated by applying them to the KRITZ benchmark.

Decision Making Method to Select Team Members Applying Personnel Behavior Based Lean Model

Jonnatan Aviles-Gonzalez,Neale R. Smith,Rupy Sawhney 대한산업공학회 2016 Industrial Engineeering & Management Systems Vol.15 No.3

Design of personnel teams has been studied from diverse perspectives; the most common are the people and systems requirements perspectives. All these point of view are linked, which is the reason why it is necessary to study them simultaneously. Considering this gap, a decision making model is developed based on factors, models, and requirements mentioned in the literature. The model is applied to a real case. The findings indicate that the Personnel Behavior Based Lean model (PBBL) can be converted into a decision making model for the selection of team members. The study is focused not only on the individual candidates’ knowledge, skills, and aptitudes, but also on how the model considers the company requirements, conflicts, and the importance of each person to the project.

Decision Making Method to Select Team Members Applying Personnel Behavior Based Lean Model

Aviles-Gonzalez, Jonnatan,Smith, Neale R.,Sawhney, Rupy Korean Institute of Industrial Engineers 2016 Industrial Engineeering & Management Systems Vol.15 No.3

Design of personnel teams has been studied from diverse perspectives; the most common are the people and systems requirements perspectives. All these point of view are linked, which is the reason why it is necessary to study them simultaneously. Considering this gap, a decision making model is developed based on factors, models, and requirements mentioned in the literature. The model is applied to a real case. The findings indicate that the Personnel Behavior Based Lean model (PBBL) can be converted into a decision making model for the selection of team members. The study is focused not only on the individual candidates' knowledge, skills, and aptitudes, but also on how the model considers the company requirements, conflicts, and the importance of each person to the project.

Transparent TiO2 nanotube array photoelectrodes prepared via two-step anodization

Kim Jin Young,Zhu Kai,Neale Nathan R,Frank Arthur J 나노기술연구협의회 2014 Nano Convergence Vol.1 No.9

Two-step anodization of transparent TiO2 nanotube arrays has been demonstrated with aid of a Nb-doped TiO2 buffer layer deposited between the Ti layer and TCO substrate. Enhanced physical adhesion and electrochemical stability provided by the buffer layer has been found to be important for successful implementation of the two-step anodization process. With the proposed approach, the morphology and thickness of NT arrays could be controlled very precisely, which in turn, influenced their optical and photoelectrochemical properties.

Canonical Form and Mathematical Interpretation of Electrolyte Solution Systems

Yoo, Kee-Youn,He, Jiwen,Amundson, Neal R. 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.2

We describe a canonical form of electrolyte solution systems for the mathematical interpretation of solid-liquid equilibrium. The canonical form is obtained from the analysis of the algebraic structure of electrolyte solution systems and the Karush-Kuhn-Tucker(KKT)conditions for the minimization of the total Gibbs free energy. As a result, the mathematical role of solid species in the solid-liquid equilibrium problem is explained as a Lagrange multiplier of a sort of the linearly constrained optimization problem. This finding will add to the development of an efficient numerical algorithm for the simulation of electrolyte solution systems.

Canonical Form and Mathematical Interpretation of Electrolyte Solution Systems

Jiwen He,Kee-Youn Yoo,Neal R. Amundson 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.2

We describe a canonical form of electrolyte solution systems for the mathematical interpretation of solid-liquid equilibrium. The canonical form is obtained from the analysis of the algebraic structure of electrolyte solutionsystems and the Karush-Kuhn-Tucker (KKT) conditions for the minimization of the total Gibs free energy. As a result,the mathematical role of solid species in the solid-liquid equilibrium problem is explained as a Lagrange multiplierof a sort of the linearly constrained optimization problem. This finding wil add to the development of an efficientnumerical algorithm for the simulation of electrolyte solution systems.

Hole transport in sensitized CdS–NiO nanoparticle photocathodes

Kang, Soon Hyung,Zhu, Kai,Neale, Nathan R.,Frank, Arthur J. Royal Society of Chemistry 2011 Chemical communications Vol.47 No.37

<P>A general chemical approach was used to synthesise NiO–CdS core–shell nanoparticle films as photocathodes for p-type semiconductor-sensitized solar cells. Compared to dye-sensitized NiO photocathodes, the CdS-sensitized NiO cathodes exhibited two orders of magnitude faster hole transport (attributable to the passivation of surface traps by the CdS) and almost 100% charge-collection efficiencies.</P> <P>Graphic Abstract</P><P>NiO–CdS core–shell nanocrystalline photocathodes display almost 100% charge-collection efficiencies and two orders of magnitude faster hole transport than the dye-sensitized NiO photocathodes. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1cc13932k'> </P>