In this article, effects of electromagnetic field and asymmetric Gaussian potential (AGP) on the bound polaron’s low energy state in quantum well are explored theoretically by the Lee-Low-Pines unitary transformation and Pekar type variational method. The variation of the ground state energy and the first excited state energy of the polaron with the Coulomb bound potential (CBP) strength at different

A system consisting of a gamma camera and a collimator is used to measure the location of a radiation source in a space where people use it or in places where people are crowded. Systems with collimators require considerable time to measure the location of the radiation source due to their low sensitivity, while can be a problem when minimizing damage through rapid tracking of radiation sources. As

Diverging collimators are used to obtain reduced images of an object or detect a wide field-of-view (FOV) by using a small gamma camera. In gamma cameras equipped with diverging collimators, a monolithic scintillator, and a pixel scintillator array, gamma rays are obliquely incident on the scintillator surface when considering a source that is located near the periphery of the FOV. In such a situation

For small-scale discharge panels of volume-dielectric barrier discharge (V-DBD) and surface-DBD (S-DBD) with an Al2O3-ceramic dielectric layer and a sinusoidal alternating current (AC)-voltage at a frequency of 55 kHz, the plasma and the ozone densities in the discharge area are estimated by analyzing the I-V (current and voltage) characteristics and ozone measuring the concentration in a liter-scale

We study the Gamow-Teller (GT) and the M1 spin transitions of the s — d shell nuclei 24Mg, 26Mg, 28Si, 32S, and 36Ar by using a quasiparticle random phase approximation (QRPA) scheme that comprises neutron-proton (np), neutron-neutron (nn) and proton-proton (pp) QRPA owing to the inclusion of the np pairing, as well as nn and pp pairing correlations. At present, we work in spherical symmetry under

We investigated defect generation in GaAs and InP on various blanket Si substrates and Si patterns with nanosized trench structures via transmission electron microscopy. The dependences of types of defects on the substrate orientation and the pattern size in GaAs and InP on nanosized patterns were analyzed. Defects that formed in a specific direction, and shapes similar to those stacking faults or

Si surface texturing generally requires an etching process to improve the anti-reflection and the self-cleaning properties of the surface. Among the various etching techniques for surface texturing, the wet etching method has been widely adopted as a relatively simple and inexpensive manufacturing method. In this study, we report the effects of hierarchical pyramid-structured Si with nanoholes formed

This paper reports a study on plane waves in a fluid incident on an infinitely long fluid-saturated porous cylinder. With consideration of both the fluid dynamic viscosity and the inelastic loss of the frame of the porous media, as well as the application-wide frequency of the Biot-Stoll model, the theoretical calculation of acoustic scattering of an acoustic wave at oblique incidence is carried out

To improve the speed of an atomic force microscope (AFM), one must improve the bandwidth of its components, and the lateral XY scanner is no exception. Sinusoidal raster scans provide a simple way of improving lateral scan rates without the need for additional hardware and/or complex control algorithms. However, a raster scan using a sinusoidal waveform leads to a non-uniform probesample velocity.

We propose a technique to measure the impact of loss of traffic function in a particular area to surrounding areas. The proposed method is applied to the city of Seoul, which is the capital of South Korea with a population of about ten million. Based on the actual road network in Seoul, we construct an abstract road network using 1 km × 1 km grid cells. The link weight of the abstract road network

The purpose of this study was to investigate the oxygen enhancement ratio (OER) effects on treatment planning for a hypoxic prostate tumor with proton scanning beams. Two different OER-based dose calculation models (the average model and the voxel model) were investigated by using hypoxic tumor models in this simulation study. For the hypoxic tumor model, an oxygen distribution with a range of 2.4–9

InSe-based van der Walls heterostructures (vdWHs) have attracted research interests recently because of their particular properties. In this work, the electronic structure and the optical properties of Mn-doped InSe/WSe2 vdWHs are investigated by using first-principles calculations. Mn doping in InSe/WSe2 vdWHs induces an increase in the system’s band gap. The optical properties of the vdWHs are also

The last author’s name should be changed from “Ki-Whwan KIM” to “Ki-Hwan KIM”, and the postal code should be changed from “27478” to “35015”.

The self-collimation of ultrasonic waves in a two-dimensional prism-shaped phononic crystal (PC) with a square lattice immersed in water was theoretically and experimentally investigated. The acoustic pressure fields at the frequencies of the first and the second pass bands were calculated with and without the PC in the acoustic path by using the finite element method. The normalized pressure distributions

This study reports the effects of NiO nanoparticle (NP) size on the sensing performance of NiO NP-decorated SnO2 nanorods (NRs). NiO NP-decorated SnO2 NRs were synthesized using a two-step process: 1) thermal evaporation of tin powders in an oxidizing atmosphere based on the vapor-liquid-solid growth mechanism and 2) solvothermal decoration of SnO2 NRs with NiO NPs. X-ray diffraction and transmission

Hyperthermia is used to destroy tumors by generating heat in the body (40–45 °C). In particular, regional hyperthermia entails intense heating of tumors rather than raising the temperature of the body. In regional hyperthermia, the prediction of the tumor temperature before treatment is essential to ensure treatment efficiency and patient safety. The goal of this study is to predict the temperature

Polyamide-6 (PA6)/silica (SiO2) composites with different sizes and concentrations of SiO2 nanoparticles were prepared via in situ anionic ring opening polymerization. An electron probe microanalyzer was used for visual examination to analyze the distribution of SiO2 nanoparticles in PA6/SiO2 composites. In addition, the thermal behavior of PA6/SiO2 composites was evaluated using thermogravimetric

We have developed a real-time dose monitoring system for a low-energy ion-beam facility. Before we developed the monitoring system, the system had given a substantial error of ±23% when we irradiated an ion beam with a dose as much as 3.0 × 1016 cm−2 on the Si substrate. Moreover, a low irradiation dose as small as 1013 cm−2 was scarcely able to be controlled because of a too short irradiation time

The BIBA (Busan Ion Beam Accelerator) is a compact linear accelerator facility using the 28 GHz ECRIS (Electron Cyclotron Resonance Ion Source) at the KBSI (Korea Basic Science Institute). The superconducting magnets of the 28 GHz ECRIS produce high magnetic fields for strong confinement of plasmas in an ion source chamber. For stable operation of the superconducting magnets, performance of cryostat

In this study, low-energy electron linear accelerators (LINACs) were proposed for applications in biological studies to replace the gamma-ray irradiators. An important parameter in biological research involves the precise dose delivery to the biological sample at an appropriate dose rate, so the beam parameters of the LINACs should be determined so as to satisfy the required dose rate. A cost effective

This paper presents the experimental results of neutron spectra measurements with organic scintillators at the copper beam dump of the 100-MeV proton linear accelerator in the Korea Multi-Purpose Accelerator Complex (KOMAC). For the measurement of the fast neutrons generated by the proton-copper nuclear reaction, two organic scintillators made of a stilbene crystal and liquid EJ-309 combined with photomultipliers

The dependency of the output factor on the field size in the passive scattering proton therapy at the National Cancer Center (NCC) in Korea was investigated through a comparison of the measured output factors. The output factor of the fields of the representative beam options was measured using a Pinpoint chamber with standard circular blocks of less than 5 cm in diameter. The measured output factors

The RAON accelerator is currently under construction to generate and accelerate stable ions and rare isotopes for various kinds of scientific programs, and it will be completed by the end of 2021. In the RAON accelerator, the beams generated by using ion sources such as electron cyclotron resonance ion source and isotope separation on-line can be used in high energy experiments such as a beam irradiation

Fourth-generation storage rings (4GSR) based on multi-bend achromat (MBA) lattices promise to deliver stable X-ray beams with higher brightness and coherence than existing third-generation light sources. The basic ingredient in achieving higher brightness is a further reduction of the electron beam emittance in storage rings dedicated to light sources. These 4GSR lattices can lead to 1 to 2 orders

Because the cross section of a nuclear reaction is defined as the probability that a nuclear reaction will occur, measuring the cross section is very important in order to understand the production yield of radioactive isotopes. In general, after a proton beam irradiates targets, the radiation from the activated targets is measured using a detector such as the HPGe detector in order to measure the

The PLS-II is a third-generation light source; it has been operating since 2011. It has a double-bend structure with non-zero dispersion along the straight section. Here, we assess three proposed upgrades to the PLS-II. First, we evaluate use of a canted insertion device beamline to increase the number of beamlines. Second, we evaluate the consequences of upgrading the bending magnet to a superbend

Radiocarbon dating using a compact or low energy accelerator mass spectrometer has been rapidly developing in recent times. A gaseous ion source was designed and simulated to reduce sample preparation times. Then, a simulation study for low-energy accelerator mass spectrometry using the designed ion source for low energy beam transport was conducted to analyze beam separation optimization. Based on

The Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL) has been successfully operating as a remarkably-stable XFEL facility in the world. The hard X-ray beamline, however, has only one undulator line (HX1) with a 26-mm undulator period for which the maximum undulator parameter K is 1.87. The lowest photon energy that can be generated from the HX1 with a maximum electron beam energy

A cancer treatment device using a very high energy electron beam has been studied as a new radiation therapy method because of its deep penetration depth, dose characteristics that are better than those of the existing X-ray method, and easy adjustment of the irradiation direction compared to existing equipment. For this treatment, compact high-energy electron accelerators are essential, and a laser

Some elementary particles used for experiments of fundamental physics have properties useful to the treatments of patients affected by oncological pathologies. They are protons and carbon ions, collectively named hadrons, hence the term hadron therapy. Hadrons, in particular carbon ions, are more precise on the target than conventional X-rays and possess radiobiological characteristics suited to treat

Over the past decades, many accelerator laboratories have put much effort into the development of compact energy-recovery linac (ERL) demonstrators to verify various physical and technical aspects of the generation, acceleration, transport and energy recovery of high brightness and high average current electron beams in a superconducting radio-frequency (SRF) linear accelerator. Beyond these goals

This study aimed to evaluate dosimetrically the feasibility of saving both the lens and the ciliary body in the treatment of a choroidal melanoma by using spatially fractionated proton minibeams. A multi-slit brass collimator was designed by using Monte Carlo simulation data and was fabricated with a 0.4-mm beam opening and a 1.1-mm center-to-center distance. A phantom was also fabricated for proton

An ion accelerator, RAON is under construction in Daejeon, Korea, by the Rare Isotope Science Project (RISP) in the Institute of Basic Science (IBS). In this accelerator various ions, such as uranium, proton, carbon, calcium, etc. are planned to be accelerated by using four kinds of superconducting cavities. The four kinds of cavities are the quarter wave resonator (QWR), half wave resonator (HWR)

In recent times, radiation therapy (RT) involving ultra-high dose rates of ionizing radiation, known as FLASH-RT, has been of great interest. Through this technology, the radiation dose can be delivered almost instantaneously within milliseconds. Many in vitro and in vivo studies have demonstrated that FLASH-RT can significantly improve normal tissue tolerance from radiation induced toxicity; this

The beam optics was evaluated to determine the specifications for the electromagnets in the proton beamline and the surface muon beamline at the RAON facility. Beam optics was evaluated, up to the fifth order by using GICOSY software; fringe field effects were also investigated. The distributions of the position and the angular divergence of 600-MeV protons were assumed to be Gaussian, and the initial

At the Korea Multi-purpose Accelerator Complex (KOMAC), a 100-MeV high-power proton linac has been used for proton-beam irradiation services for various applications and research programs, including material science, bio-medical science, semiconductor applications, as well as nuclear physics and basic science, since commissioning of the machine in 2013. Recently, demands for fast neutrons from users

Dendrimer nanoparticles (DNPs), which have been studied extensively as drug delivery systems, can be synthesized easily with zirconium without chelators. A UV/Vis spectrophotometer and a Dynamic Light Scattering (DLS) analysis were used to confirm the synthesis and the particle size of the composite. Compound B synthesized using a chelator compound was found to be more complex than compound A, and

The Ising model in an external magnetic field is one of the most outstanding and intriguing unsolved problems. One of the important properties of the Ising model in an external magnetic field is the Yang-Lee edge singularity. The zeros in the complex magnetic-field plane of the grand partition function of the Ising model on a honeycomb lattice in an external magnetic field are exactly calculated by

In this study, we report a substantial improvement in the long-term stability of low-temperature polycrystalline silicon (LTPS) thin-film transistors (TFTs) with a tandem gate insulator composed of silicon dioxide (SiO2) deposited by using atomic layer deposition (ALD) and plasma-enhanced chemical vapor deposition (PECVD). Negative-bias temperature instability (NBTI) tests showed that threshold-voltage

A Sentaurus TCAD 2-D model of β-Ga2O3 metal-oxide semiconductor field-effect transistors (MOSFETs) with a polycrystalline HfO2 gate-oxide deposited using atomic layer deposition (ALD), which has a semiconductor-on-insulator (SOI) structure, is developed. The results of model shows good agreement with the DC and the AC characteristics of the fabricated device by incorporating proper parameters for the

Toggle switches are widely used to make critical all-or-none decisions such as cell differentiation or apoptosis. While the toggle switch can be generated by using a single-type positive feedback loop (PFL), a natural toggle switch frequently emerges from interlocked PFLs composed of two different types of PFLs: one with two mutually activated units and the other with two mutually inhibiting units

The frequency dependence of heat generation in granular magnetite nanoparticles was studied using vibrating sample magnetometry and the nanoTherics Magnetherm™ hyperthermia testing system. First, the particle size and its distribution were obtained by fitting the M-H curve to the classical Langevin function weight-averaged with a modified log-normal size distribution function. Next, the ac power dissipation

This study describes a method that uses a genetic algorithm to select optimal beam angles in proton therapy and evaluates the effectiveness of the proposed algorithm in actual patients. In the use of the genetic algorithm to select the optimal angle, a gene represents the angle of each field and a chromosome represents the combination of beam angles. The fitness of the genetic algorithm, which represents

A thick AlN epilayer with an approximately 1.25-mm thickness was grown on a sapphire substrate by using a mixed source (Al+Ga of very small amount) at around 1150 °C for 2 hours and a mixed-source hydride vapor phase epitaxy (HVPE) method in a simplified reactor interlinked in series with no separation between the source and the growth zones. The simplified reactor was designed to minimize the reaction

The photoluminescence properties of crystalline Y2O3:Tb3+ nanoparticles fabricated using a liquid-phase reaction have been examined over a certain sintering temperature range for dopant activation. X-Ray diffraction (XRD) and transmission electron microscopy (TEM) were used to examine the size and the morphology of Y2O3:Tb3+ particles and disclosed the cubic Bragg peaks of the Y2O3:Tb3+ particles regardless

For large-scale cathode-material synthesis, the sol-gel process with an atomically mixed metal precursor could provide a facile route to achieve a homogeneously mixed oxide-based cathode material. However, the industrial feasibility of this strategy could be limited by the high preparation cost of the precursors. Although this can be addressed by utilizing low-cost reagents and simplifying the calcination

We report parametric modeling of the optical properties of monolayer WS2 so its dielectric response can be calculated at temperatures from 41 to 300 K from 1.5 to 6 eV. Parameterization of dielectric function was performed by dielectric-function parametric model, using previously reported dielectric function data which was obtained by spectroscopic ellipsometry. We interpolated the obtained parameters

In this paper, we investigate the network properties of the South Korean dialects. Among 153 words in “The Linguistic Atlas of Korea”, 33 words satisfying our criteria were surveyed. We set 138 basic administrative districts that make up South Korea as nodes and construct a language network by using a defined procedure. The network shows neither a small-world (small-world coefficient < 5) nor a scale-free

This paper was published with a typographical error in Acknowledgments on page 86. The grant number NRF-2019M3C1B909055 should read NRF-2019M3C1B9090559.

Recently, the solid state nuclear track detector SSNTD (CR-39) has occupied a very important place at the top of radiation detectors for passive measurements. For this reason, many investigation were done to improve the properties of this detector. In this investigation, the energy gap of that detector was calculated by measuring the transmission at different wavelengths for ten samples. Five irradiated

The purpose of this study is to compare and analyze the exposure dose of flight crew to space radiation. Flight selection was made from Gimpo Airport to domestic destinations of Jeju Island, Busan/Gimhae, Ulsan, Yeosu, Gwangju, and Daegu city. Dose measurements were based on the CARI-6/6M model developed by the Federal Aviation Administration and the Nowcast of Atmospheric Ionizing Radiation for Aviation

Since the King Sejong Korean Antarctic Research Station began operation in 1988, studies of various fields have been then carried out in polar regions and significant achievements have been yielded. However, environmental and biological radiations have not been dealt with compared to other research areas. In this study, the 137Cs distribution is investigated for environmental elements in the vicinity

150-TW, 23-fs laser pulses with high spatial and temporal qualities have been generated at 5 Hz from a chirped-pulse amplification Ti:sapphire laser. The temporal and the spatial qualities of the laser pulse were optimized and characterized for high availability in the fields of high-field science and relativistic laser-matter interactions. The pulse duration was optimized by maximizing the spectral

The unusual bias-voltage dependence of copper-hexadecafluoro-phthalocyanine (F16CuPc) molecules on Au(111) was investigated by using scanning tunneling microscopy/spectroscopy (STM/STS) at low temperatures. Depending on the bias polarity, the molecules seem to cover the whole surface of Au(111) at positive bias voltages while they are apparently invisible in STM images at negative bias voltages. Here

A new optical structure of the quantum dot (QD)-based backlight in which the QD layer was integrated on the light guide plate (LGP) was proposed. The optical performances were studied by using optical simulation, especially from the viewpoint of brightness and color uniformities. A low-index layer was inserted between the LGP and the QD layer to maintain efficient light guiding in the LGP, and an anamorphic

We visualize acoustic standing waves supported in a closed-end square pipe based on an electronic speckle pattern interferometer and measure the wavelengths of the acoustic standing waves for undergraduate physics lab courses. Generating four acoustic standing waves of frequencies below the cutoff frequency governed by the physical dimensions of the pipe, we obtain the distribution of the irradiance

We discuss the formation mechanism of GaN nanowires (NWs) with various shapes grown on Si(111) by using a plasma-assisted molecular-beam epitaxy. The GaN NWs have not only symmetrical structures but also various features such as reverse-mesa and reverse-funnel shapes. To manipulate the shape of GaN NWs, we controlled the growth kinetics of gallium (Ga) atoms by varying V/III ratio, defined as the ratio

The iron compounds in minerals of obsidians from the continental Far East, Mount Baekdu (Baedusan) near the Sino-Korean border and Kyushu in southwest Japan were studied using 57Fe Mössbauer spectroscopy. The mineral Pyroxene (FeSiO3) in obsidian was found in the metamorphic rocks of Mount Beakdusan and Kyushu. However, the mineral biotite in obsidian was found in Kyushu only. The chemical compounds

A financial time series, such as a stock market index, foreign exchange rate, or a commodity price, fluctuates heavily and shows scaling behaviors. Scaling and multi-scaling behaviors are measured for a nonstationary time series, such as stock market indices, high-frequency stock prices of individual stocks, or the volatility time series of a stock index. We review the fractality, multi-scaling, and

We studied the effect of a localized surface plasma resonance (LSPR) on ZnO-based ultraviolet photodetectors (UV-PDs) with periodic patterns of Ag nanoparticles (NPs), which had been formed by wrong a nanosphere lithography technique with a mask of polystyrene nanosphere arrays. The periodically patterned Ag NPs were positioned at the interface between the ZnO channel layer and the Si substrates, and