bluuebunny/crossref_metadata_2025 huggingface dataset:
Communication Skills Training in the Medical Curriculum
Authors: Partric Branet , Ahmed Yasar Albushra
Published: March 2021

Communication is an essential skill in the armory of any worker in the health field. It is an integral part of the skills required, not only in medical doctors, but in all health workers. Communication is more than history taking; it includes all methods of interaction with patients, patient's relatives, members of the health care team, and the public. Many studies stressed that the main complaints of patients are related to communication problems and not to clinical competency. This has contributed to an increase in the number of law suits, non-adherence to medical regimens, and the tendency of patients to keep changing physicians and hospitals. Also, it has been shown that health outcome is positively affected by proper communication. This includes patient's satisfaction and cooperation, decrease in treatment duration, decrease in painkillers requirements, and decrease in hospital stay. Also, it has been shown that communication skills can be taught and important changes in physician's behavior and in their communication skills have been demonstrated after courses of communication skills. Thus, many medical colleges in the world are including communication skills courses in their undergraduate and graduate curricula.
Teachers’ Pedagogical Competence in School-Based Management: A Case Study in a Public Secondary School at Pare-Pare, Indonesia
Authors: Syahruddin Syahruddin , Ernawati Andi , Ede Muhammad Natsir , B Abdul Rahman Mohd. Anuar , Johari Sihes Ahmad , Daud Khadijah
Published: March 2021

The extent of the role of teachers’ pedagogical competence on the practice of school-based management (SBM) was explored in this study. Interviews have been conducted in order to collect the qualitative data from the participant in Pare-Pare, South Celebes, Indonesia. It was discovered that the teachers’ pedagogical competence has not been developed as it was expected. Accordingly, it was reported that teachers’ creativity was limited by the domination of the government’s interference. It is suggested that in order to improve the quality of SBM, teachers’ continuing professional development is highly required.
Accountability in Myanmar: A Transformative Stepping-Stone?
Authors: Verelst Sebastiaan
Published: March 2021

The current approach of the international community to the question of accountability for atrocity crimes in Myanmar risks doing little to prevent such crimes in the future. It fails to shape accountability measures as a response to a complex and structural impunity problem that drives the recurrence of atrocity crimes. This article discusses building blocks for an alternative approach: a deeper understanding of impunity, a multifaceted concept of accountability, a greater awareness of the purpose and limitations of distinct accountability measures, and a deliberate connection between the accountability and prevention agendas. In doing so, the article explores how states can more effectively fulfil their international legal obligation to prevent atrocity crimes, in Myanmar and beyond.
Taxonomy of Centropomus Lacépède, 1802 (Perciformes: Centropomidae), with focus on the Atlantic species of the genus
Authors: DE FIGUEIREDO-FILHO JESSÉ MIRANDA , MARCENIUK ALEXANDRE P. , FEIJÓ ANDERSON , SICCHA-RAMIREZ RAQUEL , RIBEIRO GIOVANA S. , OLIVEIRA CLAUDIO , ROSA RICARDO S.
Published: March 2021

Centropomus Lacépède, 1802 comprises 13 species of the fishes popularly knows as snooks, distributed in both Atlantic and Pacific coasts of America. Despite several studies on the group, conflicting taxonomic classifications still exist, including overlapping diagnostic characters, rendering species diagnoses extremely difficult. Herein, we review the taxonomy of Centropomus to elucidate species identities, redefine their diagnoses and to assess interspecific relationships based on the examination of 376 specimens. The study included complementary approaches, as analyses of external morphologic characters, linear and geometric morphometrics, and molecular analyses. Forty-nine characters were used for external morphology, 17 discrete plus 32 linear measurements. Shape and size were analyzed through geometric morphometrics of 185 specimens in lateral view. Partial sequences of the gene cytochrome c oxidase I were obtained for 129 specimens representing 11 species. Based on the consistent results retrieved from the morphologic and molecular analyses, we recognized six species of Centropomus from the Atlantic coast (C. ensiferus, C. irae, C. parallelus, C. pectinatus, C. poeyi and C. undecimalis). Centropomus mexicanus is treated as a junior synonym of C. parallelus. Six species from the Pacific coast are also tentatively recognized (C. armatus, C. medius, C. nigrescens, C. robalito, C. unionensis, and C. viridis), however further studies on the Pacific species are still needed. Information on type material, diagnosis, distribution, and taxonomic comments are provided for each species. An identification key to the species of Centropomus is presented.
Gamelia bennetti sp. nov., a new Saturniidae species from Trinidad and Tobago (Lepidoptera: Bombycoidea)
Authors: COCK MATTHEW J.W. , ROUGERIE RODOLPHE
Published: March 2021

Gamelia bennetti sp. nov. is described from Trinidad, Trinidad and Tobago, West Indies, and compared with members of the Gamelia abas species group: G. abas (Cramer, [1775]), G. berliozi Lemaire, 1967, G. lichyi Lemaire, 1973, G. rubriluna (Walker, 1862) and G. septentrionalis (Bouvier, 1936). A photographic record suggests G. bennetti sp. nov. may also occur in Tobago.
Crickets of the subfamily Itarinae Shiraki, 1930 (Orthoptera: Gryllidae) from China with description of a new species and distribution and critical notes on other species
Authors: HE ZHIXIN , MA LIBIN
Published: March 2021

The Itarinae includes two genera and 60 species world-wide. Ten species are recorded from China. All Chinese species were reviewed in this study. Females of the most species were described and illustrated. Keys based on characters of male and female for Chinese species were provided respectively. As well as, a new species and revised species distribution of Itara Walker, 1869 were reported. Two types of coloration (dark and light colors) of Parapentacentrus fuscus Gorochov, 1988 were discovered and taxonomic problem of the genus Parapentacentrus Shiraki, 1930 were discussed.
New species of Philygria Stenhammar (Diptera: Ephydridae) from Germany
Authors: STUKE JENS-HERMANN
Published: March 2021

Philygria doczkali spec. nov. is described from Zugspitze (Wetterstein Mountains, Germany) in the Bavarian Alps and Philygria dispar spec. nov. is described from southern Lower Saxony (Germany).
Slurry Coating of Hydroxyapatite on Zirconia Substrate
Authors: Kim Woo Chang , Lee Jong Kook
Published: March 2021

Zirconia dental implants require excellent biocompatibility and high bonding strength. In this study, we attempted to fabricate biocompatible zirconia ceramics through surface modification by hydroxyapatite (HA) slurry coating. A hydroxyapatite slurry for spin coating was prepared using
two sizes of hydroxyapatite particles. The hydroxyapatite slurry was obtained by adjusting the solid loading, pH range, and dispersant content. The surface roughness of the HA-coated layers on the zirconia substrate depended on the change in microstructural evolution and coating thickness.
With repeated coating, the coating thickness gradually increased for both small and large particles. The specimen with two coatings had the maximum surface roughness but displayed different values depending on the size of the HA particles. High surface roughness (Ra; 0.49 μm) could
be obtained from the slurry of small particles compared with that of the large particles (Ra; 0.35 μm). During a 14 days in vitro experiment in SBF solution at pH 7.4, no changes were observed in the surface microstructure of the HA coating layer on the zirconia substrate.
Study on Dispersant and Surface Analysis of Ophthalmic Lens Materials Containing Carbon Nanotubes
Authors: Shin Su-Mi , Sung A-Young
Published: March 2021

In this study, two types of carbon nanotubes were used as ophthalmic material, and hydrogel contact lenses were polymerized by adding two types of dispersants to effectively exert the functions of carbon nanotubes. The physical properties and surfaces of the ophthalmic hydrogel lenses
prepared to confirm the functionality as a dispersant were compared and analyzed to find the utility as an ophthalmic lens material. For the polymerization, single-walled carbon nanotubes (SWCNTs), single-walled carbon nanotubes carboxylic acid functionalized (SWCCNTs), 2-hydroxyethyl methacrylate
(HEMA), ethylene glycol dimethacrylate (EGDMA, a crosslinking agent), and azobisisobutyronitrile (AIBN, an initiator) was used. In addition, as a dispersant, PVP (polyvinylpyrrolidone) and BYK-111 were copolymerized. As a result of this study, PVP increased the water content and decreased
refractive index regardless of the type of carbon, whereas BYK-111 did not show a significant difference in basic properties. Also, PVP gradually decreased breaking strength, while BYK-111 gradually increased breaking strength. BYK-111 effectively exerted the function of carbon nanotubes,
and it was confirmed whether it was dispersed through TEM. Therefore, if carbon nanotubes are used as ophthalmic materials by utilizing BYK-111, it considered to be used as functional ophthalmic lens materials.
Characterizing Fluorescence Emissions of Hairpin DNA-Templated Silver Nanoclusters by cDNA Hybridization
Authors: Kim Seyeon , Ha Geumhee , Gang Jongback
Published: March 2021

Stem-loop hairpin DNA probes have high hybridization specificity and unique selectivity to target molecules such as DNA and small molecules. DNA-templated silver nanoclusters (DNA-AgNCs) has been widely used to detect biomolecules of interest due to the photostable, bright, and efficient
methods. In this study, we measured fluorescence emission of hairpin DNA upon hybridization with cDNA and mutant cDNA (cDNA-1) or mutant cDNA containing mismatched bases in the stem region (cDNA-2). Fluorescence intensity of hairpin DNA-AgNCs in the presence of cDNA was 1.80 times higher than
that of hairpin DNA-AgNCs alone, but decreased to 66% in the presence of cDNA-1 containing mismatched base corresponding to the hairpin stem region. This study demonstrated that fluorescence intensities of hairpin DNA-AgNCs were dependent on hybridization with either wild-type and mutant cDNAs.
Electrospun Nanofibers Embedded with Copper Oxide Nanoparticles to Improve Antiviral Function
Authors: Cui Wen Ying , Yoo Hyun Jin , Li Yun Guang , Baek Changyoon , Min Junhong
Published: March 2021

Many studies on anti-bacterial/antiviral surfaces have been conducted to prevent epidemic spread worldwide. Several nanoparticles such as those composed of silver and copper are known to have antiviral properties. In this study, we developed copper oxide (CuO) nanoparticle-incorporated
nanofibers to inactivate or remove viruses. The CuO nanoparticle-incorporated nanofiber was fabricated with a hydrophobic polymer—polyvinylpyrrolidone (PVP)—using electrospinning, and CuO nanoparticles were exposed from the PVP polymer surface by etching the nanofiber with oxygen
plasma. The fabrication conditions of electrospinning and oxygen plasma etching were investigated by scanning electron microscopy (SEM), and field emission transmission electron microscopy (FETEM)/ energy dispersive spectrometry (EDS). H1N1 virus was utilized as the target sample and quantified
by RT-qPCR. The antiviral efficacy of CuO nanoparticle-incorporated nanofibers was compared against bare CuO nanoparticles. Overall, 70% of the viruses were inactivated after CuO nanoparticle-incorporated nanofibers were incubated with 102 pfu/mL of H1N1 virus solution for 4 h.
This indicates that the developed CuO nanoparticle-incorporated nanofibers have noticeable antiviral efficacy. As the developed CuO nanoparticle-incorporated nanofibers exerted promising antiviral effects against H1N1 virus, it is expected to benefit global health by preventing epidemic spread.
Color Tuning of 2-Color Based White Organic Light-Emitting Diodes with Undoped Ultra-Thin Emission Layer
Authors: Kang Shin Woo , Baek Dong-Hyun , Ju Byeong-Kwon , Park Young Wook
Published: March 2021

In the research of organic light-emitting diodes (OLEDs), the OLEDs that are fabricated via conventional doping methods have complicated structures and fabrication processes. To overcome these limitations, the ultra-thin emission layer (EML) method, which adopts a simple structure has
been effectively used in the research of OLEDs. However, studies on white color OLEDs (WOLEDs) fabricated using the ultra-thin EML method are scarce. In this paper, we report the results of color tuning for the realization of WOLEDs based on an ultra-thin EML structure. The WOLEDs were fabricated
and evaluated based on a two-color dopant system (sky-blue dopant and yellow dopant). The fabricated WOLEDs exhibited color coordinates of the International Commission on Illumination (CIE) 1931 from (0.287, 0.436) to (0.486, 0.483) according to the thickness ratio of the two dopants. This
result suggests that the WOLEDs color tuned with multi-color dopants can be fabricated based on the ultra-thin EML method, and the development of WOLEDs with high efficiency and stability can be attained in the future.
The Effects of the Rotational Speed of the Deposition Substrate on the Morphological and Current Injection Characteristics of LiF Thin Films
Authors: Choi Geun Su , Kang Shin Woo , Baek Dong-Hyun , Kwak Tae Keun , Ju Byeong-Kwon , Park Young Wook
Published: March 2021

In this study, we report the effects of the substrate rotational speed on the morphological characteristics of lithium fluoride (LiF) during thermal evaporation. LiF is used as a typical material in a vacuum-level shift-based electron injection layer and can improve both the charge
injection and light emission properties when inserted into the electrode/organic material interface of organic light-emitting diodes (OLEDs). In general OLED research, rotary evaporation is widely used to ensure uniformity. However, there are few reports regarding the effects of this rotary
evaporation method on the morphological characteristics of the thin films. Therefore, in this study, we analyzed the effects of rotary variations on the morphological and electron injection characteristics during deposition. The root mean square roughness of the LiF thin film deposited on
Alq3 changed by up to 12.3%. Additionally, the driving voltage of the electron-only device showed a difference of 2.3 V at maximum and a change in the slope of the ohmic region was demonstrated. The morphological change in the LiF thin film based on the rotational speed of the substrate
had a significant influence on the reaction at the electrode/organic material interface.
Interface Trap Charge Effects of Monolithic 3D Junctionless Field-Effect Transistors (JLFET) Inverter
Authors: Ahn Tae Jun , Yu Yun Seop
Published: March 2021

We investigated the effect of the interface trap charge in a monolithic three-dimensional inverter structure composing of JLFETs (M3DINV-JLFET), using the interface trap charge distribution extracted in the previous study. The effect of interface trap charge was compared with a conventional
M3DINV composing of MOSFETs (M3DINV-MOSFETs) by technology computer-aided design simulation. When the interface trap charges in both M3DINV-JLFET and M3DINV-MOSFET are added, the threshold voltages, on-current levels, and subthreshold swings of both JLFETs and MOSFETs increase, decrease, and
increase, respectively, and switching voltages and propagation delays of M3DINV are shifted and increased, respectively. However, since JLFET and MOSFET have different current paths of bulk and interface in channel, respectively, MOSFET is more affected by the interface trap, and M3DINV-JLFET
has almost less effect of interface trap at different thickness of interlayer dielectric, compared to M3DINV-MOSFET.
Analysis of Grain Boundary Dependent Memory Characteristics in Poly-Si One-Transistor Dynamic Random-Access Memory
Authors: Yoo Songyi , Kang In-Man , Cho Sung-Jae , Sun Wookyung , Shin Hyungsoon
Published: March 2021

A capacitorless one-transistor dynamic random-access memory cell with a polysilicon body (poly-Si 1T-DRAM) has a cost-effective fabrication process and allows a three-dimensional stacked architecture that increases the integration density of memory cells. Also, since this device uses
grain boundaries (GBs) as a storage region, it can be operated as a memory cell even in a thin body device. GBs are important to the memory characteristics of poly-Si 1T-DRAM because the amount of trapped charge in the GBs determines the memory’s data state. In this paper, we report
on a statistical analysis of the memory characteristics of poly-Si 1T-DRAM cells according to the number and location of GBs using TCAD simulation. As the number of GBs increases, the sensing margin and retention time of memory cells deteriorate due to increasing trapped electron charge. Also,
“0” state current increases and memory performance degrades in cells where all GBs are adjacent to the source or drain junction side in a strong electric field. These results mean that in poly-Si 1T-DRAM design, the number and location of GBs in a channel should be considered for
optimal memory performance.
Accurate Modeling Methodology of Laterally Diffused Metal-Oxide Semiconductor Leakage Current for Electro-Static Discharge Protection Circuit Design
Authors: Kim Jun Hyeok , Lee Su Min , Park Chan Ho
Published: March 2021

A modeling method using juncap2 physical compact model with SRH (Shockley-Read-Hall), TAT (Trap-Assisted-Tunneling), BBT (Band-to-Band Tunneling) effects is presented for the leakage current in a laterally diffused metal-oxide semiconductor (LDMOS). The juncap2 model is successfully
combined with BSIM4 model and it is validated with measurement data. The model accurately predicts the leakage current characteristics for the entire bias region and temperature.
Negative Bias Instability of InZnO-Based Thin-Film Transistors Under Illumination Stress
Authors: Lee Sangmin , Choi Pyungho , Song Minjun , Lee Gaeun , Lee Nara , Jeon Bohyeon , Choi Byoungdeog
Published: March 2021

In this study, we investigated the threshold voltage (Vth) instability of solution-processed indium zinc oxide (IZO) thin film transistors (TFTs) prior to and after negative bias illumination stress (NBIS) with varying carrier suppressors (Ga, Al, Hf, and Zr). Variations
in electrical properties of the IZO-based TFTs as a function of carrier suppressors were attributed to the differences in metal-oxygen bonding energy of the materials, which was numerically verified by calculating the relative oxygen deficient ratio from the X-ray photoelectron spectroscopy
analysis. Furthermore, the values of Vth shift (ΔVth) of the devices subjected to negative gate bias stress under 635 nm (red), 530 nm (green), and 480 nm (blue) wavelength light irradiation increased as the incident photon energy increased. IZO TFTs doped with
Ga atoms demonstrated weaker metal-oxygen bonding energy compared to the others and exhibited the largest ΔVth. This result was attributed to the suppressor-dependent distribution of neutral oxygen vacancies which determine the degrees of photon energy absorption in the IZO
films. Then, the ΔVth instability of IZO-based TFTs under NBIS correlated well with a stretched exponential function.
Design and Analysis of DC/DC Boost Converter Using Vertical GaN Power Device
Authors: Cho Min Su , Mun Hye Jin , Lee Sang Ho , An Hee Dae , Park Jin , Jang Jaewon , Bae Jin-Hyuk , Kang In Man
Published: March 2021

In this study, a high-performance vertical gallium nitride (GaN) power transistor is designed by using two-dimensional technology computer-aided design simulator. The vertical GaN transistor is used to analyze the DC/DC boost converter. The systems requiring high voltages of 1000 V
or more, such as electric vehicles, need wide devices to achieve a high breakdown voltage when using conventional power devices. However, vertical GaN transistors can be fabricated with small device area and high breakdown voltage. The proposed device has an off-current of 4.72×10−10
A/cm2, an on-current of 17,528 A/cm2, and a high breakdown voltage of 1,265 V due to good gate controllability and the very long gate-to-drain length. Using the designed device, a boost converter that doubles the input voltage was constructed and is characteristics were
examined. The designed boost converter obtained an output voltage of 1,951 V and the voltage conversion efficiency was considerably high at 97.55% when the input voltage was 1,000 V.
A Study on the Characteristics of Perovskite/ZnO-Based Ultraviolet Sensors
Authors: Shin Seong Gwan , Hur Jaehyun , Choi Hyung Wook
Published: March 2021

In this study, a UVC sensor was implemented using CH3NH3PbI3, a perovskite material. The UV sensor made with a p–i–n structure uses PEDOT:PSS as the p-type material and ZnO as the n-type material. The fabricated device
shows a responsivity of 1.60 mA/W and a detectivity of 2.25×1010 Jones under 254 nm illumination with a power density of 1.02 mW/cm2 at 2 V. In addition, the manufactured UV sensor is a self-powered perovskite-based UV sensor that can operate without external bias.
Therefore, this UVC sensor can have applications in various fields.
Dimension Effect of Sapphire Substrate in Current-Switching Device Based on Vanadium Dioxide Thin Film Controlled by Photothermal Effect
Authors: Kim Jihoon , Choi Sungwook , Lee Seul-Lee , Han Jinsil , Lee Yong Wook
Published: March 2021

The switching characteristics of a vanadium dioxide (VO2) thin-film device, in which the current flowing through the device can be switched through the photothermal effect using focused laser pulses, were investigated according to the dimensions of the sapphire substrate
on which the VO2 thin film was deposited through simulation using COMSOL Multiphysics. The physical properties of the VO2 device, modeled for the simulation, were determined according to the structural and electrical properties and photothermally controlled current-switching
characteristics of fabricated VO2 devices. For a variety of substrate dimensions of the modeled VO2 device, we explored transient variations in the temperature of some specific regions and the device current switched by laser irradiation. The investigation results revealed
that the stability of the bidirectional current-switching operation triggered on and off by laser illumination tends to increase as the area of the substrate increases with its thickness fixed. However, above a certain substrate area, the rate of improvement in the switching stability decreases
rapidly and approaches zero.
Simultaneous Measurement of pH and Temperature with Phase-Shifted Long-Period Fiber Grating Inscribed on High-Birefringence Fiber by CO2 Laser Pulses
Authors: Lee Seul-Lee , Kim Jihoon , Choi Sungwook , Han Jinsil , Shin Joong Ho , Lee Yong Wook
Published: March 2021

We propose an optical fiber grating sensor capable of simultaneously measuring pH and temperature based on a phase-shifted long-period fiber grating (PS-LPFG) inscribed on high-birefringence fiber (HBF). The PS-LPFG was fabricated on HBF with CO2 laser pulses, and a phase
shift π was induced by inserting a grating-free fiber region (GFFR) between two identical LPFGs with a grating period of ˜510 μm. The length of the GFFR was set as half of the grating period to induce a π phase shift. With the spectral characteristics of
a π-PS-LPFG exhibiting two split attenuation bands, the PS-LPFG written on HBF, which is referred to as the HB-PS-LPFG, can create two polarization-dependent transmission spectra with dual-resonance dips at different wavelengths according to two orthogonal input polarization states,
e.g., linear horizontal polarization (LHP) and linear vertical polarization (LVP). For simultaneous measurement of pH and temperature with the fabricated HB-PS-LPFG as a sensor head, the inter-resonance wavelength separation of the dual-resonance dips in each transmission spectrum obtained
for an LHP or LVP input signal was exploited as a sensor indicator. By investigating the wavelength changes of the two sensor indicators, which were induced by pH and temperature variations, linear and independent spectral responses to both pH and temperature variations were experimentally
confirmed in a pH range from 1 to 11 and a temperature range from 25 to 65 °C. Owing to the unique pH and temperature responses of the fabricated HB-PS-LPFG, ambient variations in pH and temperature could be simultaneously estimated from the measured wavelength changes and sensitivities
of the two sensor indicators.
8-Channel Biphasic Current Stimulator Optimized for Retinal Prostheses
Authors: Lee Chae-Eun , Jung Younginha , Song Yoon-Kyu
Published: March 2021

Retinal prostheses substitute the functionality of damaged photoreceptors by electrically stimulating retinal ganglion cells (RGCs). RGCs, densely packed in a small region, needs a high spatial resolution of the microelectrode, which in turn raises its impedance. Therefore, the high
output impedance circuit and the high compliance output voltage are the key characteristics of the current-source-based stimulator. Also, as the system is intended to implant in the retina, the stimulation parameter should be optimized for efficiency and safety. Here we designed 8-channel
neural stimulator customized to the retinal ganglion cell. Designed IC is fabricated in the TSMC 0.18 μm 1P6M RF CMOS process with 3.3 V supply voltage, occupying the 1060 μm×950 μm area.
Application of ZnGa2O4:Mn Down-Conversion Layer to Increase the Energy-Conversion Efficiency of Perovskite Solar Cells
Authors: Hwang Ji Yong , Bark Chung Wung , Choi Hyung Wook
Published: March 2021

The perovskite solar cell is capable of energy conversion in a wide range of wavelengths, from 300 nm to 800 nm, which includes the entire visible region and portions of the ultraviolet and infrared regions. To increase light transmittance of perovskite solar cells and reduce manufacturing
cost of perovskite solar cells, soda-lime glass and transparent conducting oxides, such as indium tin oxide and fluorine-doped tin oxide are mainly used as substrates and light-transmitting electrodes, respectively. However, it is evident from the transmittance of soda-lime glass and transparent
conductive oxides measured via UV-Vis spectrometry that they absorb all light near and below 310 nm. In this study, a transparent Mn-doped ZnGa2O4 film was fabricated on the incident surface of perovskite solar cells to obtain additional light energy by down-converting
300 nm UV light to 510 nm visible light. We confirmed the improvement of power efficiency by applying a ZnGa2O4:Mn down-conversion layer to perovskite solar cells.
Development of Magnesium-Based Material with Hydrogen-Storage Capacity of 7 wt%
Authors: Song Myoung Youp , Lee Seong Ho , Kwak Young Jun , Choi Eunho
Published: March 2021

TiCl3 was chosen as an additive to increase hydriding and dehydriding rates of Mg. In our previous works, we found that the optimum percentage of additives that improved the hydriding and dehydriding features of Mg was approximately ten. Specimens consisting of 90 wt% Mg
and 10 wt% TiCl3 (named Mg–10TiCl3) were prepared by high-energy ball milling in hydrogen. The specimens’ hydriding and dehydriding properties were then studied. Mg–10TiCl3 had an effective hydrogenstorage capacity (the quantity of hydrogen
absorbed in 60 min) of approximately 7.2 wt% at 593 K under 12 bar H2 at the second cycle. After high-energy ball milling in hydrogen, Mg–10TiCl3 contained Mg, β-MgH2, and small amounts of γ-MgH2 and TiH1.924.
TiH1.924 remained undercomposed even after dehydriding at 623 K in a vacuum for 2 h. The hydriding and dehydriding properties of Mg–10TiCl3 were compared with those of other specimens such as Mg–10Fe2O3, Mg–10NbF5, and
Mg–5Fe2O3–5Ni, for which the hydrogen-storage properties were previously reported.
Study on the Variation in Microstructure of a Ferritic Stainless Steel with Surface Roughness and Thermal Cycling in Air
Authors: Song Myoung Youp , Mumm Daniel R. , Kwak Young Jun
Published: March 2021

A ferritic stainless steel, Crofer 22 APU, is one of candidates for metallic interconnects of solid oxide fuel cells. Ferritic stainless steel Crofer 22 APU specimens with different surface roughnesses were prepared by grinding with SiC powder papers of various grits and were then thermally
cycled. Polished Crofer 22 APU specimens after one thermal cycle and five thermal cycles had relatively straight oxide layers with similar thicknesses of 30 μm, suggesting that after one cycle (total oxygen exposure time of 100 h at 1073 K), the oxidation does not progress. Micrographs
of a trench made by milling with the FIB (focused ion beam) for a Crofer 22 APU specimen rubbed with grit 80 SiC powder paper after 8 thermal cycles (total oxygen exposure time of 200 h at 1073 K), captured by ESB, InLens, and SE2, showed that the surface of the sample was very coarse and
its oxide layer was undulated. In the oxide layer, the phase of the sublayer was Cr2O3, and that of the top layer was (Cr, Mn)3O4 spinel. The sample ground with grit 80 SiC powder paper after 60 thermal cycles (total oxygen exposure time of 1500
h at 1073 K) was very coarse. Some ridges were quite straight and continuous. After 20 and 40 thermal cycles, ASR (area specific resistance) decreased as the number of grit of the SiC powder paper increased, suggesting that the polished Crofer 22 APU is better than those with rougher surfaces
for application as an interconnect of SOFC.
Understanding the Exposure Process in the Extreme Ultra Violet Lithography
Authors: Kim Sang-Kon
Published: March 2021

Although being the optical lithography, the extreme ultraviolet (EUV) lithography with 13.5-nm wavelength is very different from the deep ultraviolet (DUV) lithography with 193-nm wavelength. Hence, the understanding of the complex detailed EUV mechanisms to cause a chemical reaction
in chemically amplified resists (CARs) is required to develop EUV resists and exposure process. In this paper, for organic, metal-organic and metal-oxide resists, the electron-scattering model of exposure mechanisms needs to include the elastic and inelastic mean free paths. On top of that,
Dill’s parameters of DUV and EUV resisters from the photo-generated reaction are discussed to indicate the physical and chemical characteristics. For CAR and EUV resists, Dill B parameter is large than Dill A and B parameters.
Thermal Boundary Resistance Extraction of GaN-on-Diamond Substrate from Transmission Line Method Pattern Using Micro-Raman Spectroscopy and Thermal Simulation
Authors: Ki Ra-Seong , Seo Kwang-Seok , Cha Ho-Young
Published: March 2021

Heat dissipation properties are very important in AlGaN/GaN RF high electron mobility transistor (HEMT) devices operating at high frequency and high power. Therefore, in order to extract the thermal conductivity of the substrate and device, which are essential for the analysis
of the heat dissipation characteristics, various methods of extraction were attempted. And this experiments were conducted in parallel with micro-raman measurement and thermal simulation. As a result, it was possible to extract the thermal conductivity of each GaN-on-diamond epi layer by matching
the thermal simulation data and the shift of the micro-raman peak according to various operating states and temperatures of the transmission line method (TLM) pattern. In particular, we tried to extract the thermal boundary resistance (TBR) of the interface layer (SiNx)
for adhesion between GaN and diamond, which greatly affects the thermal conductivity of the device, and successfully extracted the following thermal conductivity value of KTBR = 3.162·(T/300)−0.8 (W/mK) from GaN and diamond interface layer.
Hydrophilicity Control of Ag-Paste Electrodes by UV/Ozone Treatment
Authors: Kim Seongwan , Yang Yunsook , Rahman Sheik Abdur , Kim Woo Young
Published: March 2021

Ag-paste is used as an electrode material in various fields as a manufacturing advantage that enables solution processing. However, when a subsequent thin film is formed on the solidified Ag-paste electrode, there is a fear that the bonding force between the Ag-paste electrode and the
subsequent thin film is weakened and peeled off due to the low surface energy of the Agpaste electrode. It is necessary to increase the surface energy of the Ag-paste electrode surface since it ultimately directly affects the yield of the device or product. In this study, the UV/ozone treatment
process was introduced to increase the Ag-paste surface energy, thereby making the surface hydrophilic. Additionally, it was confirmed that the UV/ozone treatment process affected only the surface of the Ag-paste electrode by extracting the contact resistance.
Easy-to-Fabricate K2Pd(SO3)2-Dyed Polyester Fabric with Highly Selective and Fast Response to Carbon Monoxide
Authors: Lee Junyeop , Do Nam Gon , Jeong Dong Hyuk , Kim Sae-Wan , Han Maeum , Kim Jae Keon , Kim Yeong Sam , Jung Dong Geon , Kong Seong Ho , Jung Daewoong
Published: March 2021

Carbon monoxide (CO) is an odorless, colorless, tasteless, extremely flammable, and highly toxic gas. It is produced when there is insufficient oxygen supply during the combustion of carbon to produce carbon dioxide (CO2). CO is produced from operating engines, stoves, or
furnaces. CO poisoning occurs when CO accumulates in the bloodstream and can result in severe tissue damage or even death. Many types of CO sensors have been reported, including electrochemical, semiconductor metal-oxide, catalytic combustion, thermal conductivity, and infrared absorption-type
for the detection of CO. However, despite their excellent selectivity and sensitivity, issues such as complexity, power consumption, and calibration limit their applications. In this study, a fabricbased colorimetric CO sensor is proposed to address these issues. Potassium disulfitopalladate
(II) (K2Pd(SO3)2) is dyed on a polyester fabric as a sensing material for selective CO detection. The sensing characteristics and performance are investigated using optical instruments such as RGB sensor and spectrometer. The sensor shows immediate color change
when exposed to CO at a concentration that is even lower than 20 ppm before 2 min. The fast response time of the sensor is attributed to its high porosity to react with CO. This easy-to-fabricate and cost-effective sensor can detect and prevent the leakage of CO simultaneously with high sensitivity
and selectivity toward CO.
Applications of the Water-Dispersible L-Cysteine-Capped ZnS:Mn Nanocrystals as a Selective Photosensor and an Efficient Photocatalyst
Authors: Choi Mi , Hwang Cheong-Soo
Published: March 2021

In this study, the ZnS:Mn nanocrystals (NCs) were prepared by capping the NC surface with a conventional amino acid, L-cysteine (Cys) molecules, at an acidic (pH 5) aqueous solution. The optical and physical characterizations of the ZnS:Mn-Cys-pH5 NCs were performed using various spectroscopic
methods. For instance, the UV-visible and PL spectra of the ZnS:Mn-Cys-pH5 NCs showed broad peaks at 296 and 586 nm, respectively. The obtained HR-TEM image of the ZnS:Mn- Cys-pH5 NCs product showed spherical particle images with an average size of 6.15 nm in the solid state. In addition,
measured surface charge of the colloidal ZnS:Mn-Cys-pH5 NCs using a zeta-PSA spectroscopy was −57.9 mV even at the acidic preparation condition. Therefore, the ZnS:Mn-Cys-pH5 NCs were applied as a photosensor to detect specific transition metal cations. As a result, the ZnS:Mn-Cys-pH5
NCs showed exclusive luminescence quenching effect for Fe(II) ions, which suggested that the ZnS:Mn-Cys-pH5 NCs can be applied as a photo-chemical sensor for Fe2+ ion detection in a practical water sample. The sensing ion selectivity of the ZnS:Mn-Cys-pH5 NCs was completely different
comparing to ZnS:Mn NCs surface capped with other amino acids at the same condition. In addition, the catalytic activity of the ZnS:Mn-Cys-pH5 NCs was studied in the degradation reaction of an organic dye (methylene blue) molecule under UV light irradiation.
Mechanical Properties of Epoxy Adhesive Under Thermal Aging and Their Chemical Degradation Behavior
Authors: Chung Bongjin , Sungchul Shin , Shim Jaeho , Ryu Seongwoo
Published: March 2021

Epoxy adhesive was analyzed under long term thermal aging and mechanical properties and chemical degradation were observed by X-ray photoelectron spectroscopy (XPS). Long term thermal exposure of epoxy causes a noticeable reduction in adhesive properties. We developed a predictive model
of temperature and time dependent aging. The temperature dependent aging behavior of epoxy adhesive shows good agreement with conventional Arrhenius equations. Using XPS analysis, we also discovered a correlation between chemical degradation and the adhesive properties. Decay of C–C
bonding ratio induced chain-scission of epoxy adhesive; increase of total numbers of C–O and C═O induced oxidation of epoxy adhesive during thermal exposure.
Transparent and Hard Siloxane Based Hybrid UV-Curable Coating Materials with Amphiphobic Properties
Authors: Jeong Keuk-Min , Park Sung Soo , Nagappan Saravanan , Jin Heekyung , Min Guoquan , Zhang Yongxu , Qu Minming , Zhang Yan , Ha Chang-Sik
Published: March 2021

In this study, highly transparent siloxane-based hybrid UV-curable coating materials were prepared using (acryloxypropyl)methylsiloxane monomer (APMS), a thiol-ene monomer, with benzoin ethyl ether. For the thiol-ene monomer, either pentaerythritol tetrakis(3-mercaptopropionate) (PETTMP)
or trimethylolpropane tris(3-mercaptopropionate) (TMPTMP) was used. The siloxane-based hybrid coating materials were highly transparent and hard (pencil hardness of 6–7H). The materials were also amphiphobic, with a water static contact angle of 92–100° and an oil contact angle
of 46–63°, when prepared with a high siloxane-monomer-to-PETTMP/TMPTMP ratio. In general, both hybrid coating materials exhibited improved oleophobicity, high hardness, and surface smoothness with increasing siloxane content, although the TMPTMP-based hybrid coating films exhibited
slightly higher oleophobicity (lower hydrophobicity) and a smoother surface than the PETTMP-based hybrid coating films.
Laponite-Mediated Copper Metallization by Palladium Intercalation
Authors: Kim Jeong-Soo , Suh Dongchul
Published: March 2021

An alternative catalytic method was employed using the reduction of Pd ions on the surface of cetyltrimethylammonium bromide (CTAB) treated laponite to initiate the electroless plating of copper; the deposition features of the Pd nanoparticles produced were investigated in detail. Results
indicated intercalation and reduction of Pd nanoparticles occurred at room temperature and involved interaction between the laponite and the cetyltrimethylammonium cationic templates. Organic species and amount on laponite were optimized to adjust silicate platelet interlayer distances and
platelet organophilic properties. Intercalation of Pd nanoparticles occurred between the magnesium silicate layers of laponite and this was dependent on pre-treatment and impregnation times. As impregnation is a method of producing heterogeneous catalysts, we considered Pd nanoparticles on
laponite templates could catalyze the electroless deposition of Cu to initiate metallization. Cu films fabricated on laponite templates exhibited excellent surface roughness (˜1.7 nm) and low resistivity (˜3.42 μΩ). The devised approach enabled the facile formation
of a network suitable for Cu metallization without causing substrate damage and produced metal surfaces with excellent flatness and resistivity.
Development of Antimicrobial CuO/(3-aminopropyl)Triethoxysilane Activated Carbon Fiber
Authors: Nguyen Thanh Ngoc , Hur Jaehyun , Kim Il Tae , Bui Vu Khac Hoang , Lee Young-Chul
Published: March 2021

CuO nanoparticles (NPs) have been used for the antimicrobial agent against different pathogenic microorganisms. In this study, CuO NPs are immobilized on the surface of activated carbon fiber (ACF) with the enhancement of (3-aminopropyl)triethoxysilane (APTES) as an organic binder.
The obtained fibers are evaluated by coating efficiency, structural deformation, and antimicrobial activities. In the results, APTES can improve the immobilization of CuO on the surface of ACF. Also, the curing of silane layers at high temperature leads to the high coating efficiencies as
well as structural reinforcement. The samples with drying step after APTES coating step (denoted as DA-CuO) have the highest antimicrobial activity against both Escherichia coli and Staphylococcus aureus after 24 hours treatment, respectively.
Thermoelectric Characteristics of Ultrathin Ag2Se Films with Durability Against Mechanical Stress
Authors: Park Taeho , Cho Kyoungah , Yang Seunggen , Kim Sangsig
Published: March 2021

In this study, we investigated thermoelectric materials with durability against mechanical stress using Ag2Se nanoparticle (NP) thin films and colorless polyimide (CPI) substrates. Ag2Se NP thin films and CPI substrates were produced by spin-coating, and their
thicknesses were 40 nm and 15 μm, respectively. A bendable thermoelectric film with a channel length of 40 μm and a channel area of 1.6 μm2 generated a Seebeck voltage of 1.43 mV at a temperature difference of 4.5 K. Owing to the thickness of the extremely
thin thermoelectric film and substrate, the mechanical strain was only 0.15% even when the thermoelectric devices were bent with a curvature of 3 mm. Therefore, it was determined that the bendable thermoelectric film was robust against mechanical stress.
Effect of Different Deposition Pressure on Diamond Films Deposited by Hot Filament Chemical Vapor Deposition
Authors: Jin Rongguang , Ding Ji Cheng , Song Chang Weon , Kim Kwang Ho
Published: March 2021

A hot filament chemical vapor deposition (HFCVD) method was adopted to deposit diamond films at deposition pressures ranging from 2–6 kPa. The effects of deposition pressure on the deposition rate, phase structure, and microstructure of diamond films were investigated. The surface
morphology, grain size, micro-structure, and growth rate of the diamond films were analyzed using scanning electron microscopy, X-ray diffraction (XRD), and Raman spectrometry. The experimental results showed that granules on the surface exhibited increasingly compact structure with increasing
deposition pressure. The diamond films deposited at various pressures have good compactness, and the particles on the film surfaces are arranged in an ordered manner. All films exhibited orientation along the (111) plane, which was the significant characteristic XRD peak of each diamond film.
The (111) peak intensity was the strongest for the film prepared at 2 kPa deposition pressure. Overall, the deposition rate and grain size decreased with increasing deposition pressure, provided other deposition conditions remained unchanged. However, the densification of the microstructure
and the nucleation density increased with increasing deposition pressure. Secondary nucleation became more pronounced as deposition pressure increased, and grain size decreased as nucleation density increased.
Improved Performance of High Energy Materials Based on Dinitramide Salts and Its Liquid Monopropellant
Authors: Kim Wooram , Heo Sujeong , Jeon Jong-Ki , Jo Youngmin
Published: March 2021

As an eco-friendly alternative fuel material, ammonium dinitramide (ADN, NH4N(NO2)2) is safe and stable at room temperature; however, it requires high purity for practical applications. A small amount of impurities can retard the catalytic decomposition
of the monopropellant in the thruster, lower the specific impulse, and induce side effects such as clogging of the nozzle. Therefore, we purified NH4N(NO2)2 by performing repeated extractions, adsorption by powdered activated carbon, and low-temperature extractions.
In this study, we evaluated the chemical density of purified NH4N(NO2)2 through Fourier-transform infrared spectroscopy, ultraviolet-visible spectroscopy, and ion chromatography, and obtained a final purity of 99.8%. Furthermore, we fabricated a liquid fuel
using high-purity NH4N(NO2)2 as the main oxidizing agent, and can be prepared a mono-propellant formulation that exhibited decomposition at a minimum temperature of 148 °C.
Decomposition of Hydroxylammonium Nitrate Solution Over Nanoporous CuO Supported on Honeycomb
Authors: Kim Munjeong , Kim Juyoung , Jo Young Min , Jeon Jong-Ki
Published: March 2021

We investigated the influence of a copper loading strategy over a honeycomb structure on the catalytic performance during the decomposition of a hydroxylammonium nitrate (HAN) aqueous solution. Copper was supported on the honeycomb surface by means of a metal coating method (MC), i.e.,
a method of directly coating a metal, and a metal alumina coating method (MAC), i.e., a method of coating a mixture of metal and alumina. The properties of the catalysts were analyzed by N2 adsorption, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The Cu(16.8)/honeycomb-MC
catalyst showed a lower decomposition onset temperature during the decomposition of the HAN aqueous solution compared to that over the Cu(7.0)/honeycomb- MAC catalyst, an outcome ascribed to the higher copper loading and the higher dispersion of copper in the Cu(16.8)/honeycomb-MC catalyst
compared to that in the other catalyst. The Cu(16.8)/honeycomb-MC catalyst was confirmed to have both excellent activity and heat resistance during the decomposition of a HAN aqueous solution.
Precise engineering of silver loaded polyvinyl alcohol nanogels for wound nursing care systems in operation room
Authors: Cai Lin
Published: March 2021

This study was designed to establish the composition of wound bandages based on silver nanoparticle (AgNP)loaded polyvinyl alcohol (PVA) nanogels. The AgNP nanogel (Ag-nGel) was fabricated by the fructose-mediated reduction of silver nitrate solutions within the PVA matrix. The influence
of different experimental limitations on PVA nanogel formations were examined. The nanogel particle sizes were evaluated by transmission electron microscopy and determined to range from ∼10–50 nm. Additionally, glycerol were added to the Ag-nGels, and the resulting compositions (Ag-nGel-Glu)
were coated on cotton fabrics to generate the wound bandaging composite. The cumulative drug release profile of the silver from the bandage was found to be ∼38% of the total loading after two days. Additionally, antibacterial efficacy was developed for gram positive and negative microorganisms.
Moreover, we examined in vivo healing of skin wounds formed in mouse models over 21 days. In contrast to the untreated wounds, rapid healing was perceived in the Ag-nGel-Glu-treated wound with less damaging. These findings indicate that Ag-nGel-Glu-based bandaging materials could be
a potential candidate for wound bandaging applications in the future.