A5005425166- X-ray Spectroscopy and Fluorescence Analysis
- Advanced X-ray Imaging Techniques
- Advanced Electron Microscopy Techniques and Applications
- nanoparticles nucleation surface interactions
- Corporate Finance and Governance
- Ion-surface interactions and analysis
- Material Dynamics and Properties
- Laser Material Processing Techniques
- Auditing, Earnings Management, Governance
- Laser-induced spectroscopy and plasma
- Crystallography and Radiation Phenomena
- Corruption and Economic Development
- Catalysis and Oxidation Reactions
- Nonlinear Optical Materials Studies
- Electronic and Structural Properties of Oxides
- Artificial Intelligence in Healthcare
- Cancer, Lipids, and Metabolism
- Legal and Constitutional Studies
- Cell death mechanisms and regulation
- FinTech, Crowdfunding, Digital Finance
- Particle Accelerators and Free-Electron Lasers
- Advanced Chemical Physics Studies
- Microstructure and Mechanical Properties of Steels
- RNA Interference and Gene Delivery
- Surfactants and Colloidal Systems
Pohang University of Science and Technology
2019-2024
Korea Foundation for Max Planck POSTECH
2023-2024
Kyung Hee University
2023
Baruch College
2019-2021
Chungnam National University
2008
Resonant soft X-ray scattering (RSXS) is a powerful technique for probing both spatial and electronic structures within solid-state systems.We present newly developed RSXS capability at beamline 13-3 of the Stanford Synchrotron Radiation Lightsource (SSRL), designed to enhance materials science research. This advanced setup achieves base sample temperature as low 9.8 K combined with extensive angular motions (azimuthal \phi flipping \chi), enables comprehensive exploration reciprocal space....
Melting is a fundamental process of matter that still not fully understood at the microscopic level. Here, we use time-resolved x-ray diffraction to examine ultrafast melting polycrystalline gold thin films using an optical laser pump followed by delayed hard probe pulse. We observe formation intermediate new peak, which attribute material trapped between solid and melted states, forms 50 ps after excitation persists beyond 500 ps. The peak width grows rapidly for then narrows distinctly...
Abstract Hepatitis B virus X protein (HBx) is essential for viral replication and plays an important role in pathogenesis. HBx transactivates many cellular genes participates signal transduction pathways, proliferation, apoptosis. In the present study, we report that induces apoptosis by enhancing translocation of Bax to mitochondria, followed inducing loss mitochondrial membrane potential release cytochrome C. addition, Bcl‐2, inhibitor Bax, rescues disruption DNA fragmentation induced...
The structures as building blocks for designing functional nanomaterials have fueled the development of versatile nanoprobes to understand local noncrystalline specimens. Progress in analyzing individual specimens with atomic scale accuracy has been notable recently. In most cases, however, only a limited number are inspected lacking statistics represent systems structural inhomogeneity. Here, by employing single-particle imaging X-ray free electron lasers and algorithms multiple-model 3D...
With the advent of x-ray free electron lasers (XFELs), ultrafast laser excitation leading to nonequilibrium states has become an important way investigate thermal processes. Here, we use diffraction in XFEL pump-probe experiment examine lattice dynamics 300 nm polycrystalline palladium (Pd) thin films. In our experiment, at higher fluence levels, directly observe a compression effect launched from surface skin layer heated by optical pulse which propagates across film over first tens...
Ultrafast photoinduced melting provides an essential platform for studying nonequilibrium phase transitions by linking the kinetics of electron dynamics to ionic motions. Knowledge dynamic balance in their energetics is understanding how reaction influenced femtosecond photoexcited electrons with notable time lag depending on mechanisms. Here, directly imaging fluctuating density distributions and evaluating pressure Gibbs free energy from two-temperature molecular that verified experimental...
Ultrafast laser–excited nanoparticle images reveal nonequilibrium kinetics–driven unusual surface ordering at high temperature.
The normal state of high- T c cuprates has been considered one the essential topics in high-temperature superconductivity research. However, compared to high magnetic field study it, understanding a photoinduced remains elusive. Here, we explore YBa 2 Cu 3 O 6.67 through charge density wave (CDW) with time-resolved resonant soft x-ray scattering, as well scattering. In nonequilibrium where people predict quenched superconducting based on previous optical spectroscopies, experimentally...
ABSTRACT To shed light on the role that academic research plays in Securities and Exchange Commission (SEC) rulemaking, this paper examines SEC's patterns of consumption from 2007 through 2017. We show how Business Roundtable v. SEC ruling 2011 increased consideration given to during rulemaking. find after ruling, cites more papers its proposed rules and, particular, illustrate costs regulation. This change citations results fewer negative comment letters regulations. survey academics whose...
We developed a single-shot coherent X-ray imaging instrument at the hard beamline of Pohang Accelerator Laboratory Free Electron Laser (PAL-XFEL). This experimental platform was established to conduct variety XFEL experiments, including diffraction (CDI), photon correlation spectroscopy (XPCS), and scattering (CXS). Based on forward-scattering geometry, this utilizes fixed-target method for sample delivery. It is well optimized single-shot-based experiments in which one expects observe...
We examine the deterrence effect of Dodd-Frank whistleblower provision on accounting fraud. To facilitate causal inference, we use state False Claims Acts (FCAs), under which whistleblowing about fraud at a firm invested in by state's pension fund can result monetary rewards from that state’s government. divide our sample into firms exposed and not to risk FCA during 2008 – 2010 period preceded 2011 SEC implementation provision. hypothesize already law are less affected Using companies as...
With each single X-ray pulse having its own characteristics, understanding the individual property of free-electron laser (XFEL) is essential for applications in probing and manipulating specimens as well diagnosing lasing performance. Intensive research using XFEL radiation over last several years has introduced techniques to characterize femtosecond pulses, but a simple characterization scheme, while not requiring ad hoc assumptions, address multiple aspects via data collection process...
Photoinduced nonequilibrium phase transitions have stimulated interest in the dynamic interactions between electrons and crystalline ions, which long been overlooked within Born–Oppenheimer approximation. Ultrafast melting before lattice thermalization prompted researchers to revisit this issue understand ultrafast photoinduced weakening of crystal bonding. However, absence direct evidence demonstrating role orbital dynamics disorder leaves it elusive. By performing time-resolved resonant...
X-ray structural science is undergoing a revolution driven by the emergence of Free-electron Laser (XFEL) facilities. The structures crystalline solids can now be studied on picosecond time scale relevant to phonons, atomic vibrations which travel at acoustic velocities. In work presented here, diffuse scattering employed characterize dependence liquid phase emerging from femtosecond laser-induced melting polycrystalline gold thin films using an XFEL. previous analysis Bragg peak profiles,...
Interest in atomic scale structures of individual specimens has invigorated developments high-resolution probes, which include single-particle imaging using x-ray free-electron lasers (XFELs). The demonstrated spatial resolution, however, remains at tens nanometers with difficulty collecting diffraction signals high frequency distinguished from noises. As such, various resolution-enhancement methods have been introduced, but few experimental verifications are available. Here, by carrying out...
Crystals with unique ionic arrangements and strong electronic correlations serve as a fertile ground for the emergence of exotic phases, evidenced by coexistence charge density wave (CDW) superconductivity in vanadium Kagome metals, specifically AV3Sb5 (where A represents K, Rb, or Cs). The formation star David CDW superstructure, resulting from coordinated displacements ions on corner sharing triangular lattice, has garnered significant attention efforts to comprehend influence electron...
Photoinduced ultrafast phenomena in materials exhibiting nonequilibrium behavior can lead to the emergence of exotic phases beyond limits thermodynamics, presenting opportunities for femtosecond photoexcitation. Despite extensive research, ability actively control quantum remains elusive owing lack clear evidence demonstrating explicit phase-changing kinetics through light-matter interactions. To address this drawback, we leveraged single-pulse time-resolved X-ray imaging Au nanorods...
Significance The structural link between meter-long DNA molecules and chromosomes a few microns in size their highly space-effective fault-free packing unpacking mechanisms remain puzzle. This research addressed this fundamental issue by resolving three-dimensional (3D) structure of human using cryogenic coherent X-ray diffraction tomography. Structures metaphase chromosomes, preserved frozen hydrated condition, with quantitative details on 3D electron density distributions were obtained at...
Metallic glass is a frozen liquid with structural disorder that retains degenerate free energy without spontaneous symmetry breaking to become solid. For over half century, this puzzling structure has raised fundamental questions about how impacts glass-liquid phase transition kinetics, which remain elusive direct evidence. In study, through single-pulse, time-resolved imaging using X-ray free-electron lasers, we visualized the glass-to-liquid transition, revealing previously hidden dormant...
Download This Paper Open PDF in Browser Add to My Library Share: Permalink Using these links will ensure access this page indefinitely Copy URL Anti-Corruption Laws and Geographic Reporting Transparency 70 Pages Posted: 8 Nov 2022 See all articles by Donal ByardDonal ByardCity University of New York (CUNY) - Stan Ross Department AccountancyHeemin LeeStan Accountancy, Zicklin School Business, Baruch College, City YorkEdward Xuejun LiCity AccountancyAmanda SanseverinoManhattan College Date...
To shed light on the role that academic research plays in SEC rulemaking, this paper examines SEC’s patterns of consumption from 2007 through 2017. We show how Business Roundtable v. ruling 2011 increased consideration given to during rulemaking. find after ruling, cites more papers its proposed rules and, particular, illustrate costs regulation. This change citations results fewer negative comment letters regulations. survey academics whose was cited by SEC, and majority respond description...