[PC-0005] Developing rice leaf rolling mutants by CRISPR/Cas9-mediated genome editing of homeodomainleucine zipper (HD-ZIP) IV subfamily genes

Seong-Im Park(Seong-Im Park),Mi Hyeon Cho(Mi Hyeon Cho),Ji Sun Song(Ji Sun Song),Hyeok Jin Kwon(Hyeok Jin Kwon),Song Lim Kim(Song Lim Kim),Jeongho Baek(Jeongho Baek),Young-Soon Cha(Young-Soon Cha),Hye 한국육종학회 2022 한국육종학회 공동학술발표집 Vol.2022 No.-

Properties of the Green Gold Alloys with Indium Content

Song, Jeongho,Song, Ohsung Materials Research Society of Korea 2018 한국재료학회지 Vol.28 No.4

The property changes of 18, 14, and 8K green gold alloys for jewelry are observed by adding 0.0, 3.0, and 5.0 wt% of indium (In), respectively. To check the composition of the alloys, an energy dispersive spectroscopy (EDS) analysis is conducted. Color and microstructure analysis is executed through bare-eye, macro camera, UV-VIS-NIR-colormeter, and optical microscope. The melting point, wetting angle, and hardness are measured using TGA-DTA, a wetting angle tester, and a Vickers hardness tester. The EDS analysis result demonstrates that each of the green gold alloys was manufactured with purposed contents. The color analysis result shows that the color of the alloys is similar to the color of the conventional 4 wt%-Cd 18K green gold, and the green color improves as the In content increases. The micro structure analysis result demonstrates that grain refinement improves as the amount of In increases. Enhancements in the melting point, wettability, and Vickers hardness changes appear as the In content increases and Au content decreases. The hardness is up to 260, which implies good durability. Therefore, the results suggest that the proposed 18, 14, and 8K In-added green gold alloys enhance the properties of jewelry products with regard to the green color, castability, and durability.

Properties of Polysiloxane Coated Borosilicate Lining Blocks

Song, Jeongho,Song, Ohsung The Korean Ceramic Society 2017 한국세라믹학회지 Vol.54 No.6

To improve the thermal resistance of a porous borosilicate lining block, we prepared and applied polysiloxane-fumed silica-ethanol slurry on top of the block and fired the coating layer using a torch for 5 minutes at $800^{\circ}C$. We conducted magnified characterizations using a microscope and XRD analysis to observe phase transformations, and TGA-DTA analysis to determine the thermal resistance. Thermal characterizations showed improved heat resistance with relatively high polysiloxane content slurry. Cross-sectional optical microscope observation showed less melting near the surface and decreased pore formation area with higher polysiloxane content slurry. XRD analysis revealed that the block and coating layer were amorphous phases. TGA-DTA analysis showed an endothermic reaction at around $550^{\circ}C$ as the polysiloxane in the coating layer reacted to form SiOC. Therefore, coating polysiloxane on a borosilicate block contributes to preventing the melting of the block at temperatures above $800^{\circ}C$.

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.

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.

합성 다이아몬드를 위한 산화제가 첨가된 세정공정

송정호(Song, Jeongho),이지헌(Lee, Jiheon),송오성(Song Ohsung) 한국산학기술학회 2013 한국산학기술학회논문지 Vol.14 No.8

본 연구에서는 고품질의 합성다이아몬드를 얻고자 합성다이아몬드 표면에 잔류하는 그래핀, DLC 등의 흑연계 준안정상을 효과적으로 제거하는 세정공정을 위해 왕수와 황산 외에 K2S2O8, P₂O₅, KMnO₄의 산화제가 들어간 습식세정 공정, PⅡ를 제안하였다. 이 공정은 기존의 산처리를 이용한 세정공정(PⅠ) 뿐만 아니라 신세정공정(PⅠ+PⅡ)을 함께 사용 하여 7GPa-1500℃-5minutes의 조건 하에서 합성된 200um의 다이아몬드 표면에 잔류하는 흑연과 불순물 등을 제거하기 위해 진행되었다. 이를 육안분석, 광학현미경, 마이크로라만, TGA-DTA를 통하여 확인하였다. 육안분석과 광학현미경 분 석 결과 새로운 습식세정공정(PⅠ+PⅡ) 진행 후 합성다이아몬드의 채색이 밝은 노란색으로 개선되었다. 또한 마이크로라 만 분석을 통해 1330cm-1의 다이아몬드 고유 피크 외에 1440cm-1의 흑연계 준안정상인 DLC피크가 사라지는 것을 확인하 여 정량적으로 잔류불순물의 양이 줄어든 것을 확인하였다. TGA-DTA 결과, 처리 전(PⅠ only) 흑연계 준안정상이 먼저 분해되어 770.91℃부터 열분해가 시작되었으나 신세정공정(PⅠ+PⅡ)으로 처리 후 순수한 합성다이아몬드는 892.18℃부터 시작되어 흑연계 준안정상이 효과적으로 제거된 것을 확인하였다. 이러한 신세정공정은 합성다이아몬드의 잔류불순물제 거를 통해 품질향상을 기대할 수 있었다 In this study, a wet cleaning process, PⅡ, using aqua-regia and sulfuric acid mixture with oxidant agent (K2S2O8, P₂O₅, KMnO₄, H₂O₂ etc) is proposed to remove the metastable phase of graphite such as graphene and DLC for high quality synthetic diamonds. The process employed the conventional acid cleaning process (PⅠ) as well as PⅠ+PⅡ to remove the graphite related impurities from the 200um-diamond powders synthesized at 7GPa-1500℃ -5minutes. The degree of cleaning after PⅠ and PⅠ+PⅡ has been observed by naked-eye, optical microscopy, micro-Raman spectroscopy, and TGA-DTA. After PⅠ+PⅡ, the color of diamond became more vividly yellow with enhanced saturation with naked eye and optical microscopy analysis. Moreover, the disappearance of diamond-like-carbon (DLC) peak (1440cm-1) observed by Raman spectroscopy confirmed the decrease in amount of remaining impurities. TGA-DTA results showed that the graphite impurities first started to dissolve at 770.91℃ after PI process. However, the pyrolysis started at 892.18℃ after PⅠ+PⅡ process because of the dissolution of pure diamonds. This result proved the effective dissolution of the metastable phase of graphite. We expect that the proposed PⅡ process may enhance the quality of diamonds through effective removal of surface impurities.

저품위 금합금의 PbO와 CaO를 이용한 건식 정련 공정

송정호(Jeongho Song),송오성(Ohsung Song) 한국산학기술학회 2017 한국산학기술학회논문지 Vol.18 No.4

본 연구에서는 저품위인 35wt% 금합금에 대해 80.0wt% 이상의 Au를 얻기 위한 건식 정련 공정을 제안하였다. Au35wt%-Ag5wt%-Cu60wt%의 조성을 가진 금합금에 대해 PbO/(PbO+CaO)의 혼합비를 각각 0~1로 변화시키고 플럭스/금합금의 무게비는 1/2로 하여 1200℃-5시간의 열처리를 진행하였다. 이때 공정 전, 후 시료의 조성 변화는 energy dispersive X-ray spectroscopy(EDS)로 확인하고, 공정이 완료된 후 분리된 플럭스 금속 원소 성분은 time of flight secondary ion mass spectromerty(ToF-SIMS)로 확인하였다. EDS분석 결과 플럭스의 비율이 1(PbO 단일)인 경우 Au의 함량이 35.0wt%에서 86.7wt%로 가장 크게 향상되었고, 다른 플럭스 조성의 경우도 84wt% 이상으로 정련이 가능하였다. 또한 2/3 혼합비의 플럭스에서 Ag가 플럭스부로 빠져나가는 손실이 가장 적었다. 플럭스부의 ToF-SIMS 분석 결과 플럭스의 비율이 1, 0 일 때 Au+의 특성 피크의 강도가 각각 349, 37로 측정되었다. Au의 손실을 고려하였을 때 CaO 단일 플럭스의 사용이 더 유리할 수 있었으나, 이 정도의 신호강도는 무시할 수 있는 정도로 판단되었다. 따라서 혼합플럭스를 이용한 건식열처리를 통해 효과적인 금의 정련이 가능하여 경제적인 습식제련의 전처리 공정으로 사용될 수 있음을 확인하였다. We proposed a pyrometallurgical process to achieve gold alloy with an Au content of more than 80wt% from low grade (<35wt%) gold alloys. We performed the heat treatment at a temperature of 1200℃ for 5 hrs using Au35wt%-Ag5wt%-Cu60wt% gold alloys mixed with 1/2 weighed PbO and CaO flux by varying the ratio of PbO/(PbO+CaO) from 0 to 1. We investigated the change in content of the samples with energy dispersive X-ray spectroscopy (EDS) and time of flight secondary ion mass spectrometry (ToF-SIMS). The EDS results showed that the Au content increased from 35.0wt% in the PbO-only sample to 86.7wt% (in the PbO/(PbO+CaO) 1:1 sample), while the other samples achieved more that 84wt%. In addition, the 2/3 flux ratio sample showed the lowest Ag loss into the flux. In the ToF-SIMS results, the PbO only and CaO only fluxes had Au+ peak intensities of 349 and 37, respectively. Although the CaO-only flux might be more favorable considering the loss of Au into the flux, we concluded that the amount of Au lost into the flux could be ignored. Our results imply that that the pyrometallurgical process using a mixed flux is an effective hydrometallurgical process.

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)

주석과 황동 용탕 드롭렛을 이용한 디스크형 응고체 제조

송정호(Jeongho Song),이태경(Tae-Kyeong Lee),리광훈(Gwang-Hoon Rhee),송오성(Ohsung Song) 한국산학기술학회 2016 한국산학기술학회논문지 Vol.17 No.8

유가금속이 혼합된 비철합금의 습식 제련의 용이성을 위해서, 주석과 황동 용탕으로부터 표면적이 넓은 평판형 응고 체를 제조하는 공정을 제안하였다. 금속 용탕을 그라파이트 도가니의 노즐로부터 드롭렛(droplet) 형상으로 떨어뜨릴 수 있도 록 STAR-CCM+ 프로그램을 이용하여 노즐의 직경을 0.5, 1.0, 2.0 mm로 변화시키며 시뮬레이션을 진행하였다. 주석과 황동 모두 0.5 mm 노즐에서는 융액이 흐르지 않았으며, 2.0 mm 에서는 연속적인 분사가 진행되었고, 1.0 mm에서는 목적한 드롭 렛이 형성되었다. 시뮬레이션 결과를 바탕으로 목적한 드롭렛이 형성되는 1.0 mm 노즐을 이용하여 용융된 주석, 황동 용탕 드롭렛을 40°의 경사를 가진 티타늄 충격판에 충돌시켜 표면적이 증가된 디스크형 응고체를 10분 내에 성공적으로 제조하였 다. 평면 응고체의 무게, 평균두께, 표면적은 주석의 경우 각각 0.15 g, 107.8 ㎛, 3.71 cm2 이었으며, 황동의 경우 1.16 g, 129.15 ㎛, 23.98 cm2로 확인되었다. 형성된 응고체의 표면적은 드롭렛에 대비하여 각각 8.2, 17.6배로 증가되었다. 제안된 공정을 이용하여 다른 유가금속 합금의 표면적 향상 공정에도 비용과 시간 절감이 기대되었다. This paper proposes a simple process to fabricate tin and brass metal discs with a large surface area from molten droplets for the wet-refining process of nonferrous metals by assuming they have precious metal elements. To optimize the droplet condition in a graphite crucible, the appropriate nozzle size was determined using a simulation program (STAR-CCM+) by varying the diameters (0.5, 1.0, and 2.0 mm). The simulation results showed that both tin and brass do not fall out with a 0.5 mm diameter nozzle but they do fall out in continuous ribbon mode with a 2.0 mm nozzle. Only the 1.0mm nozzle was expected to fabricate droplets. Finally, solidified metal discs were fabricated successfully with the 1.0 mm nozzle within 10 minutes by impacting the droplets with a cooling water flowing over a Ti plate placed at the 40° falling direction. The weight, average thickness, and surface area of the tin discs were 0.15 g, 107.8 ㎛, and 3.71 cm2, respectively. The brass discs were 1.16 g, 129.15 ㎛, and 23.98 cm2, respectively. The surface area of the tin and brass disc were 8.2 and 17.6 times the size of the tin and brass droplets, respectively. This process for precious metal extraction is expected to save cost and time.