Determination of Hund's coupling in 5d oxides using resonant inelastic x-ray scattering

Yuan, Bo,Clancy, J. P.,Cook, A. M.,Thompson, C. M.,Greedan, J.,Cao, G.,Jeon, B. C.,Noh, T. W.,Upton, M. H.,Casa, D.,Gog, T.,Paramekanti, A.,Kim, Young-June American Physical Society 2017 Physical Review B Vol.95 No.23

<P>We report resonant inelastic x-ray scattering (RIXS) measurements on ordered double-perovskite samples containing Re5+ and Ir5+ with 5d(2) and 5d(4) electronic configurations, respectively. In particular, the observedRIXS spectra of Ba2YReO6 and Sr2MIrO6 (M = Y, Gd) show sharp intra-t(2g) transitions, which can be quantitatively understood using a minimal 'atomic' Hamiltonian incorporating spin-orbit coupling. and Hund's coupling J(H). Our analysis yields lambda = 0.38(2) eV with J(H) = 0.26(2) eV for Re5+ and lambda = 0.42(2) eV with J(H) = 0.25(4) eV for Ir5+. Our results provide sharp estimates for Hund's coupling in 5d oxides and suggest that it should be treated on equal footing with spin-orbit interaction in multiorbital 5d transition-metal compounds.</P>

The Role of Minimally Invasive Plate Osteosynthesis in Rib Fixation: A Review

Michael Bemelman, M.D.,Mark van Baal, M.D., Ph.D,Jian Zhang Yuan, M.D.,Luke Leenen, M.D., Ph.D., Professor, FACS 대한흉부외과학회 2016 Journal of Chest Surgery (J Chest Surg) Vol.49 No.1

Multi-height observations of magnetoacoustic cut-off frequency in a sunspot atmosphere

Yuan, D.,Sych, R.,Reznikova, V. E.,Nakariakov, V. M. Springer-Verlag 2014 Astronomy and astrophysics Vol.561 No.-

Enabling the fast lithium storage of large-scalable γ-Fe2O3/Carbon nanoarchitecture anode material with an ultralong cycle life

Sadeeq Ullah,Benoît D.L. Campéon,Shumaila Ibraheem,Ghulam Yasin,Rajesh Pathak,Yuta Nishina,Tuan Anh Nguyen,Yassine Slimani,Qipeng Yuan 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.101 No.-

Two-dimensional (2D) materials are generally expected to have superior lithium-ion (LIBs) performancescompare with their bulk counterpart as they display superior specific surface area. In this context, thedevelopment of 2D maghemite would be of great interest owing to its high theoretical specific capacity,natural abundance, and relatively low cost and toxicity; however, maghemite do not have a layered crystallinestructure. Herein, to overcome this hindrance, c-Fe2O3 has been enclosed within a 2D carbonmatrix via a simple and facile synthesis strategy based on the complexation of ethylene glycol with aqueousiron species by hydrolysis and condensation reactions followed by its carbonization. As obtained 2Dcarbon c-Fe2O3 nanosheet composite (CEG-Fe) is composed of 41.3 wt.% carbon and 10.2 wt.% Fe. Whenused as anode materials in LIBs, CEG-Fe demonstrated the enhanced initial discharge capacity of1589 mAh g 1 at 100 mA g 1, and outstanding ultralong cycling performance with the significant stablecapacity of 700 mAh g 1 and 230 mAh g 1 at the higher current rate of 0.5 A g 1 and 10 A g 1 for morethan 300 and 6000 cycles, respectively. These results enable a promising avenue to design the large-scaleproduction of 2D CEG-Fe sheets-based nanostructured anode materials for next-generation LIBs for largescaleenergy storage applications.

EVOLUTION OF FAST MAGNETOACOUSTIC PULSES IN RANDOMLY STRUCTURED CORONAL PLASMAS

Yuan, D.,Pascoe, D. J.,Nakariakov, V. M.,Li, B.,Keppens, R. IOP Publishing 2015 The Astrophysical journal Vol.799 No.2

<P>We investigate the evolution of fast magnetoacoustic pulses in randomly structured plasmas, in the context of large-scale propagating waves in the solar atmosphere. We perform one-dimensional numerical simulations of fast wave pulses propagating perpendicular to a constant magnetic field in a low-beta plasma with a random density profile across the field. Both linear and nonlinear regimes are considered. We study how the evolution of the pulse amplitude and width depends on their initial values and the parameters of the random structuring. Acting as a dispersive medium, a randomly structured plasma causes amplitude attenuation and width broadening of the fast wave pulses. After the passage of the main pulse, secondary propagating and standing fast waves appear. Width evolution of both linear and nonlinear pulses can be well approximated by linear functions; however, narrow pulses may have zero or negative broadening. This arises because narrow pulses are prone to splitting, while broad pulses usually deviate less from their initial Gaussian shape and form ripple structures on top of the main pulse. Linear pulses decay at an almost constant rate, while nonlinear pulses decay exponentially. A pulse interacts most efficiently with a random medium with a correlation length of about half of the initial pulse width. This detailed model of fast wave pulses propagating in highly structured media substantiates the interpretation of EIT waves as fast magnetoacoustic waves. Evolution of a fast pulse provides us with a novel method to diagnose the sub-resolution filamentation of the solar atmosphere.</P>

Kinetically Blocked Stable Heptazethrene and Octazethrene: Closed-Shell or Open-Shell in the Ground State?

Li, Yuan,Heng, Wee-Kuan,Lee, Byung Sun,Aratani, Naoki,Zafra, José,L.,Bao, Nina,Lee, Richmond,Sung, Young Mo,Sun, Zhe,Huang, Kuo-Wei,Webster, Richard D.,Ló,pez Navarrete, Juan T.,Kim, Dongh American Chemical Society 2012 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.134 No.36

<P>Polycyclic aromatic hydrocarbons with an open-shell singlet biradical ground state are of fundamental interest and have potential applications in materials science. However, the inherent high reactivity makes their synthesis and characterization very challenging. In this work, a convenient synthetic route was developed to synthesize two kinetically blocked heptazethrene (<B>HZ-TIPS</B>) and octazethrene (<B>OZ-TIPS</B>) compounds with good stability. Their ground-state electronic structures were systematically investigated by a combination of different experimental methods, including steady-state and transient absorption spectroscopy, variable temperature NMR, electron spin resonance (ESR), superconducting quantum interfering device (SQUID), FT Raman, and X-ray crystallographic analysis, assisted by unrestricted symmetry-broken density functional theory (DFT) calculations. All these demonstrated that the heptazethrene derivative <B>HZ-TIPS</B> has a closed-shell ground state while its octazethrene analogue <B>OZ-TIPS</B> with a smaller energy gap exists as an open-shell singlet biradical with a large measured biradical character (<I>y</I> = 0.56). Large two-photon absorption (TPA) cross sections (σ<SUP>(2)</SUP>) were determined for <B>HZ-TIPS</B> (σ<SUP>(2)</SUP><SUB>max</SUB> = 920 GM at 1250 nm) and <B>OZ-TIPS</B> (σ<SUP>(2)</SUP><SUB>max</SUB> = 1200 GM at 1250 nm). In addition, <B>HZ-TIPS</B> and <B>OZ-TIPS</B> show a closely stacked 1D polymer chain in single crystals.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2012/jacsat.2012.134.issue-36/ja304618v/production/images/medium/ja-2012-04618v_0015.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja304618v'>ACS Electronic Supporting Info</A></P>

The Net Energy Values of Corn, Dried Distillers Grains with Solubles and Wheat Bran for Laying Hens Using Indirect Calorimetry Method

Ning, D.,Yuan, J.M.,Wang, Y.W.,Peng, Y.Z.,Guo, Y.M. Asian Australasian Association of Animal Productio 2014 Animal Bioscience Vol.27 No.2

The present study was conducted to estimate the NE values of corn, dried distillers grains with solubles (DDGS) and wheat bran (WB) for laying hens based on an indirect calorimetry method and nitrogen balance measurements. A total of 576 twenty-eight-wk-old Dwarf Pink-shell laying hens were randomly assigned to four groups fed a basal diet (BD) or a combination of BD with 50% corn or 20% DDGS or 20% WB, with four replicates each. After a 7-d adaptation period, each replicate with 36 hens were kept in one of the two respiration chambers to measure the heat production (HP) for 6 days during the feeding period and subsequent 3-d fasting. The equilibrium fasting HP (FHP) provided an estimate of NE requirements for maintenance (NEm). The NE values of test feedstuffs was estimated using the difference method. Results showed that the heat increment that contributed 35.34 to 37.85% of ME intake was not influenced by experimental diets (p>0.05) when expressed as Mcal/kg of DM feed intake. Lighting increased the HP in hens in an fed-state. The FHP decreased over time (p<0.05) with the lowest value determined on the third day of starvation. No significant difference between treatments was found on FHP of d 3 (p>0.05). The estimated AME, AMEn, and NE values were 3.46, 3.44 and 2.25 Mcal/kg DM for corn, 3.11, 2.79, and 1.80 Mcal/kg DM for DDGS, 2.14, 2.10, and 1.14 Mcal/kg DM for WB, respectively. The net availability of AME of corn tended to be numerically higher than DDGS and WB (p = 0.096). In conclusion, compared with corn, the energy values of DDGS and WB were overestimated when expressed on an AME basis.

Structure of Penta-Alanine Investigated by Two-Dimensional Infrared Spectroscopy and Molecular Dynamics Simulation

Feng, Yuan,Huang, Jing,Kim, Seongheun,Shim, Ji Hyun,MacKerell, Alexander D.,Ge, Nien-Hui American Chemical Society 2016 The Journal of physical chemistry B Vol.120 No.24

<P>We have studied the structure of (Ala)(5), a model unfolded peptide, using a combination of 2D IR spectroscopy and molecular dynamics (MD) simulation. Two different isotopomers, each bis-labeled with C-13=O and C-13=O-18, were strategically designed to shift individual site frequencies and uncouple neighboring amide-I' modes. 2D IR. spectra taken under the double-crossed <pi/4, -pi/4, Y, Z > polarization show that the labeled four-oscillator systems can be approximated by three two-oscillator systems. By utilizing the different polarization dependence of diagonal and cross peaks, we extracted the coupling constants and angles between three pairs of amide-I' transition dipoles through spectral fitting. These parameters were related to the peptide backbone dihedral angles through DFT calculated maps. The derived dihedral angles are all located in the polyproline-II (ppII) region of the Ramachandran plot. These results were compared to the conformations sampled by Hamiltonian replica-exchange MD simulations with three different CHARMM force fields. The C36 force field predicted that ppII is the dominant conformation, consistent with the experimental findings, whereas C22/CMAP predicted similar population for alpha(+), beta, and ppII, and the polarizable Drude-2013 predicted dominating beta structure. Spectral simulation based on MD representative conformations and structure ensembles demonstrated the need to include multiple 2D spectral features, especially the cross-peak intensity ratio and shape, in structure determination. Using 2D reference spectra defined by the C36 structure ensemble, the best spectral simulation is achieved with nearly 100% ppII population, although the agreement with the experimental cross-peak intensity ratio is still insufficient. The dependence of population determination on the choice of reference structures/spectra and the current limitations on theoretical modeling relating peptide structures to spectral parameters are discussed. Compared with the previous results on alanine based oligopeptides, the dihedral angles of our fitted structure, and the most populated ppII structure from the C36 simulation are in good agreement with those suggesting a major ppII population. Our results provide further support for the importance of ppII conformation in the ensemble of unfolded peptides.</P>

On the Performance Limits of Cryogenically Operated SiGe HBTs and Its Relation to Scaling for Terahertz Speeds

Jiahui Yuan,Cressler, J.D.,Krithivasan, R.,Thrivikraman, T.,Khater, M.H.,Ahlgren, D.C.,Joseph, A.J.,Jae-Sung Rieh IEEE 2009 IEEE transactions on electron devices Vol.56 No.5

<P>The goal of achieving terahertz (THz) transistors within the silicon material system has generated significant recent interest. In this paper, we use operating temperature as an effective way of gaining a better understanding of the performance limits of SiGe HBTs and their ultimate capabilities for achieving THz speeds. Different approaches for vertical profile scaling and reduction of parasitics are addressed, and three prototype fourth-generation SiGe HBTs are compared and evaluated down to deep cryogenic temperatures, using both dc and ac measurements. A record peak f<SUB>T</SUB>/f<SUB>max</SUB> of 463/618 GHz was achieved at 4.5 K using 130-nm lithography (309/343 GHz at 300 K), demonstrating the feasibility of reaching half-THz f<SUB>T</SUB> and f<SUB>max</SUB> simultaneously in a silicon-based transistor. The BV<SUB>CEO</SUB> of this cooled SiGe HBT was 1.6 V at 4.5 K (BV<SUB>CBO</SUB> = 5.6 V), yielding a record f<SUB>T</SUB> times BV<SUB>CEO</SUB> product of 750 GHzldrV (510 GHzldrV at 300 K). These remarkable levels of transistor performance and the associated interesting device physics observed at cryogenic temperatures in these devices provide important insights into further device scaling for THz speeds at room temperature. It is predicted in a new scaling roadmap that f<SUB>T</SUB>/f<SUB>max</SUB> of room-temperature SiGe HBTs could potentially achieve 782/910 GHz at a BV<SUB>CEO</SUB> of 1.1 V at the 32-nm lithographic node.</P>

Search forXYZstates inϒ(1S)inclusive decays

Shen, C. P.,Yuan, C. Z.,Ban, Y.,Aihara, H.,Asner, D. M.,Badhrees, I.,Bakich, A. M.,Barberio, E.,Behera, P.,Bhardwaj, V.,Bhuyan, B.,Biswal, J.,Bondar, A.,Bonvicini, G.,Bozek, A.,Brad,ko, M.,Browde American Physical Society 2016 Physical Review D Vol.93 No.11

<P>The branching fractions of the Upsilon(1S) inclusive decays into final states with a J/psi or psi(2S) are measured with improved precision to be B Upsilon(1S) -> J/psi + anything = (5.25 +/- 0.13(stat) +/- 0.25(syst) x 10(-4) and B Upsilon(1S) -> psi(2S) + anything = (1.23 +/- 0.17(stat) +/- 0.11(syst)) x 10(-4). The first search for Upsilon(1S) decays into XYZ states that decay into a J/psi or a psi(2S) plus one or two charged tracks yields no significant signals for XYZ states in any of the examined decay modes, and upper limits on their production rates in Upsilon(1S) inclusive decays are determined.</P>