Thermodynamic Calculations and Parameter Variations for Improving the Extraction Efficiency of Dy in Ternary Alloy System

Sun‑Woo Nam,Sang‑Min Park,Do‑Hyang Kim,Taek‑Soo Kim 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.3

The extraction behavior of dysprosium (Dy) in a rapidly solidified Dy–Fe–B alloy system consisting of Dy2Fe14Band Dy6Fe23phases was investigated using the liquid metal extraction (LME) process. Liquid magnesium (Mg) was selected as the solventmetal in LME because it forms intermetallic compounds with Dy but not with iron (Fe) and boron (B) in this process. Thediffusion behavior of Dy was estimated through thermodynamic calculations and subsequently confirmed by process parameterssuch as temperature and reaction time. As the temperature increases, the extraction rate increases and the maximumextraction efficiency is about 74% Dy for 1 h at 1000 °C. As the reaction time increases, we achieved the maximum extractionefficiency of 95% Dy after 24 h at 900 °C. The factor affecting Dy extraction ratio up to 6 h is Dy6Fe23phase, after which theextraction mainly occurs in Dy2Fe14Bphase. Furthermore, the diffusion behavior is described in detail with analysis basedon microstructural and compositional properties. The effects of process parameters on extraction rate are also discussed.

변색 실활치에 대한 carbamide peroxide gel의 표백효과

박선아,김선호,황윤찬,오병주,윤창,박영준,정선와,황인남,오원만 大韓齒科保存學會 2002 Restorative Dentistry & Endodontics Vol.27 No.4

The bleaching of discolored nonvital teeth is conservative treatement that satisfy the cosmetic desire. The most common method for this treatement, walking bleaching, is using 30% hydrogen peroxide and sodium perborate. Many alternatives are suggested for preventing the external cervical root resorption that is the common complication of the nonvital teeth bleaching with 30% hydrogen peroxide. The same extent of oxidation reactions as that resulted by the bleaching with the application of 30% hydrogen peroxide and sodium perborate can also be acquired more safely by materials that contain 10% carbamide peroxide, used primarily for the bleaching of vital teeth. Therefore, this study was performed to evaluate the efficacy of 10% and 15% carbamide peroxide bleaching gel in nonvatal teeth bleaching. The internal bleaching of intentionally discolored teeth was performed in vitro with 10% carbamide peroxide (Group 1), 15% carbamide peroxide (Group 2), mixture of distilled water and sodium perborate (Group 3), and mixture of 30% hydrogen peroxide and sodium perborate (Group 4). The bleaching materials were refreshed following 3, 6, 9 and 12 days. To evaluate the bleaching effect, the color change of the crowns was measured at 1, 2, 3, 4, 7 and 15 days of bleaching using the colorimeter. The results were as follows : 1. L^* and ΔE^* values were increased with time in all bleaching agents(p<0.01). 2. There was no significant difference in L^* and ΔE^* value among bleaching agents. 3. Δ^* value higher than 3 was shown after 3 days of bleaching with 10% carbamide peroxide gel, 1 day with 15% carbamide peroxide gel, 4 days with mixture sodium perborate and distilled water and 4 days with mixture sodium perborate and 30% hydrogen peroxide, respectively. These results revealed that the use of 10% and 15% carbamide peroxide bleaching gel in non-vital teeth bleaching is as effective as mixture of distilled water and sodium perborate and mixture of 30% hydrogen peroxide and sodium perborate. Accordingly, carbamide peroxide could be used clinically to bleach discolored non-vital teeth.

한국 전통장류가 한우 반힘줄모양근(M. Semitendinosus)으로 제조한 건염햄의 육질 특성에 미치는 영향

성필남,조수현,강근호,김동훈,박범영,강선문,박경미,Seong, Pil-Nam,Cho, Soo-Hyun,Kang, Geun-Ho,Kim, Dong-Hoon,Park, Beom-Young,Kang, Sun-Moon,Park, Kyoung-Mi 한국축산식품학회 2013 한국축산식품학회지 Vol.33 No.6

This study was conducted to develop a processing method for dry-curing beef ham with Korean traditional sauces and to investigate the quality properties of the dry-cured beef hams. Semitendinosus muscle from Hanwoo was spread with sundried salt (C), sun-dried salt mixed with red pepper paste (T1), and sun-dried salt mixed with soybean paste (T2), and inserted into washed Hanwoo large intestine. It was then dried and fermented for 75 d. Moisture contents of the hams were 46-48%, without any significant differences. T1 showed the lowest pH among the three dry-cured hams, while water holding capacity (WHC) of T2 was found the lowest (p<0.05). In mechanical color determination, C showed higher CIE $a^*$ and CIE $b^*$ than T1 and T2 (p<0.05), however CIE $L^*$ did not show any significant difference. In texture, T1 demonstrated significantly lower springiness than C (p<0.05). The sensory properties of all dry-cured hams did not show any significant difference, but T1 indicated a higher taste, saltiness and overall acceptability than others, whereas C gathered the highest score in color and flavor. In conclusion, the dry-curing by combination of sun-dried salt mixed with red pepper sauce (T1) showed higher quality properties of the Hanwoo dry-cured ham. 우리나라 전통장류를 건염햄 제조에 접목한 건염햄의 제품을 개발하기 위해 염지과정에서 첨가한 고추장과 된장이 건염햄 품질에 미치는 영향을 조사하고자 실시하였다. 천일염(C), 천일염+고추장(T1), 천일염+된장(T2)을 한우의 반힘줄모양근(m.emitendinosus)의 표면에 골고루 발라주고 세척한 한우 대장에 충진한 후 75일 동안 건조 및 발효시켰다. 한우 반힘줄모양근 건염햄 품질을 조사한 결과, 건염햄 수분함량은 46.45-48.04% 수준으로 유의적인 차이는 없었다. T1은 모든 처리구 중에서 pH가 가장 낮았고 T2는 WHC가 가장 낮았다(p<0.05). 기계적 육색 측정에서 C가 $a^*$와 $b^*$가 전통장류 처리(T1, T2)보다 높았으나(p<0.05), $L^*$은 유의적인 차이가 없었다. 조직감에서 T1은 C보다 탄력성이 유의적으로 낮았다(p<0.05). 관능평가 결과 모든 처리구에서 유의적인 차이가 없었고 C는 제품색과 향미가 높은 점수를 받은데 반해, T1은 높은 맛, 짠맛, 그리고 전체적 기호도가 다른 처리구에 비해 높았다.

忠南 錦山郡 西臺山 一帶의 나비目 昆蟲相

남상호,조영호,장석원,박영준,이선영,나선희 대전대학교 기초과학연구소 2002 自然科學 Vol.13 No.2

충청남도 금산군 서대산 일대의 나비목 곤충상을 조사한 결과 22과 344종 1,936개체가 조사되었다. 이중 밤나방과가 102종 589개체, 자나방과가 67종 440개체로 이 2과가 전체의 50%이상을 차지하였다. 자나방과의 두줄가지나방은 1,936 개체중 85개체가 채집되어 4.4%의 가장 높은 우점도를 나타냈다. 월별 우점종은 4월 노랑무늬물결자나방, 5월 별박이세줄나비, 6월 목도리불나방, 7월 청백무늬밤나방, 8월 두줄가지나방, 9월은 털뿔가지나방이 조사되었다. 월별 종다양도는 4월 2.95, 5월 3.37, 6월 4.63, 7월 4.62, 8월 4.23, 9월은 2.97이었으며, 평균 종다양도는 3.80으로 서대산 일대의 나비목 곤충상은 비교적 양호한 편으로 조사되었다. This study was carried out to investigate Lepidopterous insect fauna from Mt. Seodae in Geumsan-gun, Chungnam. The samples were collected from April to September in 2001. Total 1,936 individuals belonging to 344 species, 22 families of Lepidoptera were collected. The sum of individuals belonging to Noctuidae and Geometridae exceed 50% of the collected samples in that Noctuidae was consisted of 102 species 589 individuals and Geometridae was 67 species 440 individuals. The dominant species in surveyed area was Rikiosatoa grisea of Geometridae, the dominant species by month were Idiotephria amelia in April, Neptis pryeri in May, Paraona staudinger in June, Ercheia niveostrigata in July, Rikiosatoa grisea in August and Alcis angulifera in September respectively. Species diversity indices by month were 2.93 in April, 3.37 in May, 4.63 in June, 4.62 in July, 4.23 in August and 2.97 in September respectively. Mean species diversity index was 3.80.

복합레진의 조건등색에 관한 연구 : D_(65), A, C, FCW and TL84

박기정,황윤찬,김선호,오원만,황인남 전남대학교 치의학연구소 2003 구강과학 Vol.15 No.2

There were problems in selecting exact colors of composite resins currently used in clinic by examining with naked eyes. This study was done to present a criterion in selection of the most proper light sources and materials by measuring metamerism index of the light curing composite resins with spectrocolorimeter. Metamerism is present when two objects appear to be the same color in one illuminant but different in another. This is due to the fact that they have different spectral curves that fail to match under the second illuminant. In this study, five light polymerized composite resins; Esthet-X, Filteck Z250, Filteck A110, Charisma, Vitalescence which are currently used in clinic were chosen based on Vita shade. Five samples were made for shade of each product with Teflon mold(diameter: 15mm, thickness: 2mm). Compressed resins with glass slab were light polymerized with a visible light curing unit(Optilux 500, 13mm tip diameter, Demetron, USA) for 60 seconds. Polymerized samples were removed and those were grinded to 2.0mm in thickness with sand papers(#600 & #1000). Samples were carefully prepared without fingerprints and impurities in grinding procedure and kept in distilled water for a week at room temperature. Metamerism index of each samples on a Barium sulfate plate(L^(*)=96.54, a^(*)=0.19, b^(*)=0.01) prepared for sample fixation were measured with spectrocolorimeter(Miniscan XE plus. Model 4000s. Hunter Lab, USA) by applying standard light source D65, C, Fcw, TL84' and A. Standardization was done with Reference standard(X=80.8, Y=85.7, Z=90.8) and Light trap. Samples were kept in distilled water at room temperature in all procedures. The results are as follows. 1. Different resins using same Vita shade showed recognizable color difference(ΔE^(*)>2). 2. All composites had Ml below accepted value 0.5 between standard illuminant(D65, C, & A) and below 1.5 under fluorescent condition (Fcw & TL84). 3. Ml value between D65 and A showed higher value than Ml value between other source of light(p<0.01). 4. All resins except Z25O showed Ml value that A3 is higher than Al between D65 and A(p<0.05).

니켈과 코발트를 함유한 황산용액으로부터 Cyanex 272에 의한 코발트의 용매추출

박경호,정선희,남철우,신선명,김동수 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.11

The solvent extraction to separate and recover cobalt and nickel from sulfuric acid solution was studied using Cyanex 272 in kerosene. The solution processed was equivalent to that expected from leaching of a matte, intermediate product of manganese nodules. The extraction of both metals increased with increasing equilibrium pH and extractant concentration. However, cobalt was preferentially extracted over nickel. The extraction efficiencies of cobalt and nickel were 80% and 1.9% respectively with 0.2M Cyanex and O/A of 1 at equilibrium pH 5.0. The separation factor of Co/Ni increased with raising the extraction temperature (205 at 20℃, and at 441 at 50℃). The saponification of Cynanex 272 increased the extraction of cobalt due to the increase of equilibrium pH. Nickel (0.40 g/l) loaded in an organic phase could be scrubbed with a solution containing 10 g/l Co at equilibrium pH of 6.0. The stage numbers and cobalt recoveries in extraction and stripping processes required for the counter current operations are predicted using the equilibrium isotherm plots. (Received May 19, 2004)

위암과 식도암이 병발된 다발성 원발성 악성종양 1예

박사영,이나영,이효진,이선영,최진혁,이순남,심강섭,성순희,한운섭 梨花女子大學校 醫科大學 醫科學硏究所 1996 EMJ (Ewha medical journal) Vol.19 No.3

Multiple primary cancer means that more that two cancers occur independently in an individual. Recently, the incidence of multiple primary cancer has increased with lengthened survival, of cancer patients, development of new diagnostic technique and increased clinical evaluation. We report a patient who had adenocarcinoma of stomach combined with squamous cell carcinoma of esophagus simultaneously.

복합레진의 조건등색에 관한 연구

박기정,황윤찬,김선호,오원만,황인남 大韓齒科保存學會 2003 Restorative Dentistry & Endodontics Vol.28 No.5

This study was done to present a criterion in selection of the most proper light sources and materials by measuring metamerism index(MI) of the light curing composite resins with spectrocolorimeter. Metamerism is defined when two objects appear to be the same color in one illuminant but different in another. This is due to the fact that they have different spectral curves that fail to match under the second illuminant. In this study, A1 & A3 shade of five light curing composite resins (Esthet-X, Filteck Z250, Filteck A110. Charisma. Vitalescence) were chosen based on Vita shade. Five samples were made for shade of each product with Teflon mold (diameter: 15mm, thickness: 2mm). Metamerism index of each samples on a Barium sulfate plate(L^(*)=96.54, a^(*)=0.19, b^(*)=0.01) prepared for sample fixation were measured with spectrocolorimeter(Miniscan XE plus. Model 4000s. Hunter Lab. USA) by applying standard light source D_(65), C. Fcw, TL84 and A. Standardization was done with reference standard(X=80.8, Y=85.7, Z=90.8) and light trap. The results were as follows. 1. Different resins with same Vita shade showed recognizable color difference (ΔE^(*)>2). 2. All composites had MI below accepted value 0.5 between standard illuminant(D_(65), C, & A) and below 1.5 under fluorescent condition (Fcw & TL84). 3. MI value between D_(65) and A showed higher value than MI value between other source of light(p<0.01). 4. All resins except Z250 showed MI value that A3 is higher than A1 between D_(65) and A(p<0.05).

웨이브릿 변환 영역 적응필터에 의한 유한 임펄스 응답 필터시스템 확인

박순규,박남천,이수흠 慶南大學校 附設 工業技術硏究所 1998 硏究論文集 Vol.15 No.2

기존의 시간영역직 접형 유한 임펄스 응답 적응필터는 그 구조가 매우 간단하기 때문에 여러 분야에 응용되고 있으나, 이 적응필터는 일반적으로 수렴률이 매우 늦다. 변환영역 적응필터는 적응 알고리듬의 수렴속도 증가를 위해 유익하게 사용된다. 웨이브릿 변환은 프로세스가 비정적인 경우에도 Karhunen-Loeve변환과 매우 유사하다. 그러므로 웨이브릿 변환된 출력의 자동상관 마트릭스는 거의 대각이며, 변환 영역에서 간단한 전처리를 하면 수렴률을 매우 향상시킬 수 있다. 또한 변환에 Harr 웨이브릿을 이용하면 곱셈없이 변환이 가능하다. 이 논문에서는 웨이브릿 변환 영역 적응필터를 구성하고, 이를 유한 임펄스 시스템 확인에 적용하였다. 컴퓨터 시뮬레이션 결과를 DET 영역 적응 유한 임펄스응답 적응필터에 의한 결과와 함께 나타내었다. The conventional time domain direct-form FIR filter has been used for a variety of application, since it presents a very simple implemention, however, in general, the convergence rate of this adaptive filter is very slow. The transform domain adaptive filter can be used advantageously to increase the speed of convergence of the adaptive algorithm. The wavelet transform behaves as a good approximation to Karhunen-Loeve(KL) transform even when the underlying process is nonstationary. Therefore, the autocorrelation matrix of the wavelet transformed output is nearly diagonal. By using a simple preconditioning in the transformed domain, the conditioning can be improved resulting in dramatic increase in the convergence rates. And by using the Harr wavelet, we can transform without multiplication arithmetic. In this paper, a wavelet transform domain adaptive filter has been constructed and applied to the FIR filter system identification. Computer simulation results are shown with the results obtained by the DFT domain adaptive FIR filter.

식물체로부터 추출한 물질이 상추 종자의 발아 및 생장에 미치는 영향

박건남,이민경,황선주,김학윤,이인중,신동현,김길웅 경북대학교 농업과학기술연구소 1999 慶北大農學誌 Vol.17 No.-

This study was conducted to detect the allelopathic effect of water and ethanol extracts from 4 plant species (Lactuca sativa L., Ambrosia elatior L., Oenothenra odorata Jasp., Ginkgo biloba L.) on germination and growth of lettuce seeds. A little bit higher inhibitory effect was obtained in ethanol extracts rather than water extracts. Allelopathic effects varied in the source of extracts and concentrations of 4 plant species and the highest allelopathic effect appeared in 10% solution, regardless of plant species.