Color Enhancement of Natural Sapphires by High Pressure High Temperature Process

Song, Jeongho,Noh, Yunyoung,Song, Ohsung The Korean Ceramic Society 2015 한국세라믹학회지 Vol.52 No.2

We employed the high-pressure high temperature (HPHT) process to enhance the colors of natural sapphires to obtain a vivid blue. First, we analyze the content of the coloring agent $Fe_2O_3$ using the wavelength dispersive X-ray fluorescence (WD-XRF) method. The HPHT procedure operates under 1 GPa at various temperatures of 1700, 1750, and $1800^{\circ}C$ for 5 minutes using a cubic press. We determine the color changes using the optical microscopic images, UV-VIS near-infrared (NIR) spectra, micro-Raman spectra, and Fourier transform-infrared (FT-IR) spectra for all sapphire samples before and after the treatment. The optical microscopic results indicate that the HPHT process can enhance the sapphire color to a vivid blue at temperatures above $1750^{\circ}C$. The UV-VIS-NIR spectra identify the color changes explicitly and quantitatively through providing the Lab color scales and color differences. Both results demonstrate that the colors of natural sapphires can be enhanced to a vivid blue using the HPHT process above $1750^{\circ}C$ under 1 GPa for 5 minutes.

A Surface Etching for Synthetic Diamonds with Nano-Thick Ni Films and Low Temperature Annealing

Song, Jeongho,Noh, Yunyoung,Song, Ohsung The Korean Ceramic Society 2015 한국세라믹학회지 Vol.52 No.4

Ni (100 nm thick) was deposited onto synthesized diamonds to fabricate etched diamonds. Next, those diamonds were annealed at varying temperatures ($400{\sim}1200^{\circ}C$) for 30 minutes and then immersed in 30 wt% $HNO_3$ to remove the Ni layers. The etched properties of the diamonds were examined with FE-SEM, micro-Raman, and VSM. The FE-SEM results showed that the Ni agglomerated at a low annealing temperature (${\sim}400^{\circ}C$), and self-aligned hemisphere dots formed at an annealing temperature of $800^{\circ}C$. Those dots became smaller with a bimodal distribution as the annealing temperature increased. After stripping the Ni layers, etch pits and trigons formed with annealing temperatures above $400^{\circ}C$ on the surface of the diamonds. However, surface graphite layers existed above $1000^{\circ}C$. The B-H loop results showed that the coercivity of the samples increased to 320 Oe (from 37 Oe) when the annealing temperature increased to $600^{\circ}C$ and then, decreased to 150 Oe with elevated annealing temperatures. This result indicates that the coercivity was affected by magnetic domain pinning at temperatures below $600^{\circ}C$ and single domain behavior at elevated temperatures above $800^{\circ}C$ consistent with the microstructure results. Thus, the results of this study show that the surface of diamonds can be etched.

Color Evolution in Single Crystal Colored Cubic Zirconias With Annealing Atmosphere and Temperature

Song, Jeongho,Noh, Yunyoung,Song, Ohsung The Korean Ceramic Society 2016 한국세라믹학회지 Vol.53 No.4

Color change in single-crystal, yellow, red, purple, and colorless cubic zirconias (CZs) was investigated as a function of annealing in vacuum and air atmosphere at $800-1400^{\circ}C$ for 30 min, for development of a damascene process of plugging a precious metal paste at the elevated temperature. Coloring-element contents of the CZs were evaluated using WD-XRF, and the color change determined visually by naked eye, and using a digital camera and UV-Vis-NIR color analyzer. WD-XRF showed that all of the CZs had cubic-phase stabilizer elements and coloring elements. All CZs that underwent vacuum annealing exhibited a slight color change at $<900^{\circ}C$, while their colors began to change to black at $1100^{\circ}C$, and became opaque black at $1400^{\circ}C$. After air annealing, there was almost no color change up to $1400^{\circ}C$. Since red and purple CZs showed greater color difference (CD) values than the others, the degree of CD is likely to depend on the original color of the CZ due to the different stabilities of their coloring elements during annealing. Based on our results, it is suggested that annealing in air at $<900^{\circ}C$ is advantageous, and assorted colored CZs can be used for precious metal damascene.

도시기상 관측을 위한 메타데이터의 표준화

송윤영(Yunyoung Song),채정훈(Jung-Hoon Chae),최민혁(Min-Hyeok Choi),박문수(Moon-Soo Park),최영진(Young Jean Choi) 한국대기환경학회 2014 한국대기환경학회지 Vol.30 No.6

인천국제공항의 안개 특성에 따른 안개 안정 지수 FSI(Fog Stability Index) 개발 및 검증

송윤영(Yunyoung Song),염성수(Seong Soo Yum) 한국기상학회 2013 대기 Vol.23 No.4

Au 나노 분말 첨가에 따른 염료감응형 태양전지의 물성

송정호 ( Jeongho Song ),노윤영 ( Yunyoung Noh ),최민경 ( Minkyoung Choi ),김광배 ( Kwangbae Kim ),송오성 ( Ohsung Song ) 대한금속재료학회(구 대한금속학회) 2016 대한금속·재료학회지 Vol.54 No.7

We prepared working electrodes with blocking layers containing 0.0∼0.5 wt% Au nano powder to improve the energy conversion efficiencies (ECEs) of a dye sensitized solar cell (DSSC). TEM, FE-SEM, and AFM were used to characterize microstructure. XRD and micro-Raman were used to determine the phase and localized surface plasmon resonance (LSPR) effect of the blocking layer with Au nano powder. A solar simulator and a potentiostat were used to confirm the photovoltaic properties of the DSSC with the Au nano powder. From the results of the microstructure analysis, we confirmed that the Au nano powder had particle sizes of less than 70 nm, dispersed uniformly on the blocking layer. Based on the phase and composition analysis, we identified the presence of Au, and the Raman intensity increased as the amount of Au was increased. The photovoltaic results showed that the ECE reached 5.52% with the Au addition, compared to an ECE of 5.00% without the Au addition. This enhancement was due to the increased LSPR of the blocking layer with the Au addition. Our results suggest that we might improve the efficiency of a DSSC by the proper addition of Au nano powder on the blocking layer. †(Received November 24, 2015; Accepted February 22, 2016)

Self-efficacy, Symptom, and Quality of Life in Breast Cancer Survivors

Yunyoung Choi,Bomi Hong,Akter Jotsna,Su Kyung Song,Sun Young Rha,Jiyeon Lee 한국간호과학회 2021 한국간호과학회 학술대회 Vol.2021 No.10

Aim(s): In Korea, 5-year cancer relative survival rate of breast cancer has been increased over years, and the quality of life of those survivors is challenged by side effects of cancer treatments, psychological and social effects. Self-efficacy, one’s belief in his or her capabilities, has positive effect on quality of life in patients with breast cancer. The purpose of this study was to evaluate symptoms, self-efficacy, and quality of life (QOL), and identify factors associated with quality of life among breast cancer survivors (BCS) in Korea. Method(s): A descriptive correlational study was conducted. A total of 190 BCSs participated in this study. BCSs’ symptoms, self-efficacy, and quality of life were measured. Descriptive statistics, Pearson’s correlation, t-test, and multiple regression analysis were conducted to identify contributing factors of quality of life. Result(s): Among subscales of self-efficacy for coping, the mean value of self-efficacy for seeking information was the highest. The second highest subscales were maintaining activities and accepting/positive attitude/decision-making. The most significant symptom was fatigue (3.26±2.74), and the mean value of QOL was 69.61(±20.80). Associations between self-efficacy subscales and QOL were all significant and positive, weak to moderate in size (0.288≤r≤0.35, p<.001), and there was negative and high correlation between symptom severity and QOL (r=-0.52, p<.001). Multiple regression analysis demonstrated that symptom severity (β=-.42, p<.001), self-efficacy for seeking spiritual coping (β=.18, p<.05), and functional status (β=-.18, p<.05) significantly predicted BCSs’ QOL and explained 37.5 % of the variance. Conclusion(s): Self-efficacy for seeking spiritual coping, symptom severity, and functional status were significant contributing factors of QOL of breast cancer survivors. In addition to managing physical symptoms, it is recommended to assess self-efficacy for spiritual coping to provide holistic care to BCSs to improve QOL.

Effects of a Competency-Based Education Program for Inpatient Psychiatric Nurses: A Pre-Post Intervention Study

( Song Young-ok ),( Kim Haeyoung ),( Nam Yunyoung ),( Choe Kwisoon ),( Ha Jeongmin ) 한국정신간호학회 2022 정신간호학회지 Vol.31 No.1

Purpose: This study aimed to develop a competency-based educational program for strengthening the competency of psychiatric nurses and evaluate its effects. Methods: The study used a quasi-experimental design. Participants included 64 psychiatric nurses in South Korea: 33 nurses (32 females, 1 male) in the experimental group and 31 nurses (26 females, 5 males) in the control group. A competency-based education program for psychiatric nurses was developed through a literature review and discussion with 12 experts. The program addressed eight topics and provided 24 hours of education over 4 days, for 6 hours each day. The collected data via questionnaires were analyzed statistically. Results: The education program enhanced overall clinical nursing competence and strengthened professional self-growth competence. The management and teaching competencies of both the experimental and the control groups also increased significantly. Conclusion: The findings of this study presented an educational program to strengthen the clinical competency of psychiatric nurses and it was proven that the education had a capacity-building effect.

작동전극부에 나노다이아몬드를 첨가한 염료감응형 태양전지의 물성 연구

노윤영 ( Yunyoung Noh ),김광배 ( Kwangbae Kim ),최민경 ( Minkyoung Choi ),송오성 ( Ohsung Song ) 대한금속재료학회(구 대한금속학회) 2016 대한금속·재료학회지 Vol.54 No.1

We prepared a TiO2 blocking layer containing 0~0.5 wt% nano diamonds (NDs) to increase the effective surface area of working electrodes in a dye sensitized solar cell (DSSC). The result was a DSSC with a 0.45 cm2 active area of a glass/FTO/blocking layer (TiO2 with NDs)/TiO2/dye/electrolyte/100 nm Pt/glass structure. The microstructure of the blocking layer was examined by optical microscope, FESEM, and AFM. UV-VIS-NIR was used to determine the optical absorbance of the working electrodes containing NDs. The photovoltaic properties for the ND added DSSC, such as short circuit current density, open circuit voltage, fill factor, energy conversion efficiency, and impedance, were checked using a solar simulator and potentiostat. Microstructure characterization showed that the NDs were evenly dispersed in the blocking layer. The absorbance in the visible light regime increased as the ND content increased. The photovoltaic properties indicated that energy conversion efficiency increased from 3.53% to 4.96% with 0 wt% and 0.4 wt% ND addition. This was due to the decreased interface resistance of the working electrode and the increased surface area and shunt resistance of the blocking layer resulting from the addition of the NDs. The DSSC with 0.5 wt% NDs was less efficient due to a reduction of the effective electron transport area caused by excess NDs. Our results suggest that we can improve the efficiency of a DSSC by proper addition of NDs into the blocking layer.

나노급 Cr/Pt 이중층이 사용된 염료감응태양전지의 저온 열처리에 따른 물성변화

노윤영 ( Yunyoung Noh And ),송오성 ( Oh Sung Song ) 대한금속재료학회(구 대한금속학회) 2014 대한금속·재료학회지 Vol.52 No.10

Abstract: The properties of the Cr/Pt bilayered catalytic layer with additional low temperature annealing using a dye sensitized solar cell (DSSC) were investigated. A DSSC device with a structure with an effective area of 0.45 cm2 glass/FTO/blocking layer/TiO2/N719 (dye)/electrolyte/50 nm Pt/50 nm Cr/glass was prepared. For comparison, 100 nm-thick Pt and Cr counter electrodes on flat glass substrates were also prepared using the same procedure. The sheet resistance was examined using a four point probe. The photovoltaic properties, such as the short circuit current density, open circuit voltage, fill factor, energy conversion efficiency (ECE), and impedance, were characterized using a solar simulator and potentiostat. The phases of the bilayered films were examined by X-ray diffraction. The microstructure of the bilayered films was characterized by atomic force microscopy. The measured sheet resistance of the counter electrode with annealing increased to. The measured ECE of the dye-sensitized solar cell devices with vacuum annealed Cr/Pt bilayer counter electrodes decreased abruptly. The interface resistance at the interface between the counter electrode and electrolyte increased as the annealing time increased. The increase in catalytic activity of the Cr/Pt bilayer before annealing resulted from the effect of a compressive strain field. After 10 minutes, the strain field was removed by annealing. The new phases of Pt3Cr and CrPt by annealing led to drastically decreased catalytic activity.