• Title/Summary/Keyword: Thin Layer

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Fabrication of 3D Paper-based Analytical Device Using Double-Sided Imprinting Method for Metal Ion Detection (양면 인쇄법을 이용한 중금속 검출용 3D 종이 기반 분석장치 제작)

  • Jinsol, Choi;Heon-Ho, Jeong
    • Clean Technology
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    • v.28 no.4
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    • pp.323-330
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    • 2022
  • Microfluidic paper-based analytical devices (μPADs) have recently been in the spotlight for their applicability in point-of-care diagnostics and environmental material detection. This study presents a double-sided printing method for fabricating 3D-μPADs, providing simple and cost effective metal ion detection. The design of the 3D-μPAD was made into an acryl stamp by laser cutting and then coating it with a thin layer of PDMS using the spin-coating method. This fabricated stamp was used to form the 3D structure of the hydrophobic barrier through a double-sided contact printing method. The fabrication of the 3D hydrophobic barrier within a single sheet was optimized by controlling the spin-coating rate, reagent ratio and contacting time. The optimal conditions were found by analyzing the area change of the PDMS hydrophobic barrier and hydrophilic channel using ink with chromatography paper. Using the fabricated 3D-μPAD under optimized conditions, Ni2+, Cu2+, Hg2+, and pH were detected at different concentrations and displayed with color intensity in grayscale for quantitative analysis using ImageJ. This study demonstrated that a 3D-μPAD biosensor can be applied to detect metal ions without special analysis equipment. This 3D-μPAD provides a highly portable and rapid on-site monitoring platform for detecting multiple heavy metal ions with extremely high repeatability, which is useful for resource-limited areas and developing countries.

Electrochemical Behavior of Tin and Silver during the Electrorecycling of Pb-free Solder (Sn-Ag-Cu) Waste (폐무연솔더(Sn-Ag-Cu)의 전해재활용 시 주석과 은의 전기화학적 거동 연구)

  • Kim, Min-seuk;Lee, Jae-chun;Kim, Rina;Chung, Kyeong-woo
    • Resources Recycling
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    • v.31 no.3
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    • pp.61-72
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    • 2022
  • We investigated the electrochemical behavior of Sn (93.0 %)-Ag (4.06 %)-Cu (0.89 %) during electrolysis of Pb-free solder waste to recover tin and silver. A thin strip of the solder waste produced by high-temperature melting and casting was used as a working electrode to perform electrochemical analysis. During anodic polarization, the current peak of an active region decreased with an increase in the concentration of sulfuric acid used as an electrolyte. This resulted in the electro-dissolution of the working electrode in the electrolyte (1.0 molL-1 sulfuric acid) for a constant current study. The study revealed that the thickening of an anode slime layer at the working surface continuously increased the electrode potential of the working electrode. At 10 mAcm-2, the dissolution reaction continued for 25 h. By contrast, at 50 mAcm-2, a sharp increase in the electrode potential stopped the dissolution in 2.5 h. During dissolution, silver enrichment in the anode slime reached 94.3% in the 1 molL-1 sulfuric acid electrolyte containing a 0.3 molL-1 chlorine ion, which was 12.7% higher than that without chlorine addition. Moreover, the chlorine enhanced the stability of the dissolved tin ions in the electrolyte as well as the current efficiency of tin electro-deposition at the counter electrode.

Non-Destructive Scientific Analysis of the Gold Fabric Excavated of Cheongsong Shim's Grave (청송심씨 묘에서 출토된 금직물의 비파괴 과학적 분석)

  • Lee, Hwang-Jo;Wi, Koang-Chul
    • Journal of Conservation Science
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    • v.38 no.3
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    • pp.243-253
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    • 2022
  • Using non-destructive analytical methods, we identified the material characteristics of two gold fabric artifacts excavated from the Cheongsong Sim clan (Bugeum Wonsam, Jikgeum Chima), including the artifact condition, fiber type, surface contamination, and metallic threads. We found that the artifacts were buried and had turned brown; thus, we were unable to determine their original color. The fiber type was determined to be silk from cocoons, based on scanning electron microscopy, Fourier transform infrared (FT-IR) analyses of Amide I, II, III, and IV peaks, and color reactions Further, the FT-IR and X-ray fluorescence (XRF) analyses identified the white and black stains as natural resin hydrolyzed substances, such as lipids and proteins, that occurred as microbial decomposition due to body decay. Finally, the XRF analyses identified the thin gold layer of the metallic yarn as gold (Au). According to the FT-IR data and the color reaction to the metallic yarn medium, the adhesive component of the medium was a product of-Amides I, II, III, and 3000 cm-1 within Amides A and B (an animal type), respectively. Thus, the medium was identified as Hanji (Korean paper), which is made from domestically produced Broussonetia kazinoki fibers.

A Study on the Passive Vibration Control of Large Scale Solar Array with High Damping Yoke Structure (고댐핑 요크 구조 적용 대형 태양전지판의 수동형 제진에 관한 연구)

  • Park, Jae-Hyeon;Park, Yeon-Hyeok;Park, Sung-Woo;Kang, Soo-Jin;Oh, Hyun-Ung
    • Journal of Aerospace System Engineering
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    • v.16 no.5
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    • pp.1-7
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    • 2022
  • Recently, satellites equipped with high-performance electronics have required higher power consumption because of the advancement of satellite missions. For this reason, the size of the solar panel is gradually increasing to meet the required power budget. Increasing the size and weight of the solar panel is one of the factors that induce the elastic vibration of the flexible solar panel during the highly agile maneuvering of the satellite or the mode of vibration coupling to the satellite or the mode of vibration coupling to the micro-jitter from the on-board appendages. Previously, an additional damper system was applied to reduce the elastic vibration of the solar panel, but the increase in size and mass of system was inevitable. In this study, to overcome the abovementioned limitations, we proposed a high -damping yoke structure consisting of a superplastic SMA(Shape Memory Alloy) laminating a thin FR4 layer with viscoelastic tape on both sides. Therefore, this advantage contributes to system simplicity by reducing vibrations with small volume and mass without additional system. The effectiveness of the proposed superelastic SMA multilayer solar panel yoke was validated through free vibration testing and temperature testing using a solar panel dummy.

BEEF MEAT TRACEABILITY. CAN NIRS COULD HELP\ulcorner

  • Cozzolino, D.
    • Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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    • 2001.06a
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    • pp.1246-1246
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    • 2001
  • The quality of meat is highly variable in many properties. This variability originates from both animal production and meat processing. At the pre-slaughter stage, animal factors such as breed, sex, age contribute to this variability. Environmental factors include feeding, rearing, transport and conditions just before slaughter (Hildrum et al., 1995). Meat can be presented in a variety of forms, each offering different opportunities for adulteration and contamination. This has imposed great pressure on the food manufacturing industry to guarantee the safety of meat. Tissue and muscle speciation of flesh foods, as well as speciation of animal derived by-products fed to all classes of domestic animals, are now perhaps the most important uncertainty which the food industry must resolve to allay consumer concern. Recently, there is a demand for rapid and low cost methods of direct quality measurements in both food and food ingredients (including high performance liquid chromatography (HPLC), thin layer chromatography (TLC), enzymatic and inmunological tests (e.g. ELISA test) and physical tests) to establish their authenticity and hence guarantee the quality of products manufactured for consumers (Holland et al., 1998). The use of Near Infrared Reflectance Spectroscopy (NIRS) for the rapid, precise and non-destructive analysis of a wide range of organic materials has been comprehensively documented (Osborne et at., 1993). Most of the established methods have involved the development of NIRS calibrations for the quantitative prediction of composition in meat (Ben-Gera and Norris, 1968; Lanza, 1983; Clark and Short, 1994). This was a rational strategy to pursue during the initial stages of its application, given the type of equipment available, the state of development of the emerging discipline of chemometrics and the overwhelming commercial interest in solving such problems (Downey, 1994). One of the advantages of NIRS technology is not only to assess chemical structures through the analysis of the molecular bonds in the near infrared spectrum, but also to build an optical model characteristic of the sample which behaves like the “finger print” of the sample. This opens the possibility of using spectra to determine complex attributes of organic structures, which are related to molecular chromophores, organoleptic scores and sensory characteristics (Hildrum et al., 1994, 1995; Park et al., 1998). In addition, the application of statistical packages like principal component or discriminant analysis provides the possibility to understand the optical properties of the sample and make a classification without the chemical information. The objectives of this present work were: (1) to examine two methods of sample presentation to the instrument (intact and minced) and (2) to explore the use of principal component analysis (PCA) and Soft Independent Modelling of class Analogy (SIMCA) to classify muscles by quality attributes. Seventy-eight (n: 78) beef muscles (m. longissimus dorsi) from Hereford breed of cattle were used. The samples were scanned in a NIRS monochromator instrument (NIR Systems 6500, Silver Spring, MD, USA) in reflectance mode (log 1/R). Both intact and minced presentation to the instrument were explored. Qualitative analysis of optical information through PCA and SIMCA analysis showed differences in muscles resulting from two different feeding systems.

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Development of cordycepin fortified meat production in Hanwoo steers II. Effects of mycelia of Cordyceps militaris cultured from grains on cordycepin deposition in muscles of finishing Hanwoo steers (Cordycepin 강화 한우고기 생산에 관한 연구 II. 곡립기주 동충하초 균사체 급여가 한우고기내 cordycepin 축적에 미치는 영향)

  • Kim, W.Y.;Lee, S.H.;Kim, D.H.;Lee, J.H.;Nho, W.G.;Hwang, J.H.;Yeo, J.M.
    • Journal of Practical Agriculture & Fisheries Research
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    • v.11 no.1
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    • pp.53-61
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    • 2009
  • The present experiment was conducted to examine the effects of mycelia of Cordyceps militaris cultured from grains on cordycepin deposition in muscles and plasma glutathione peroxidase activity in finishing Hanwoo steers. Four steers were divided into two groups. Control group received no supplement whereas treatment group received 1 % mycelia of C. militaris of their feed intake for 80 days prior to slaughtering. Final body weight, average daily gain, dry matter intake were not affected by the treatment. But the activity of plasma glutathione peroxidase was numerically higher for the treatment group than for the control group (15.70 vs 9.23 unit). Furthermore, cordycepin deposition in muscles on the treatment group was identified with thin layer chromatography. The results of the present experiment show that cordycepin could be deposited in muscles of Hanwoo beef by feeding mycelia of Cordyceps militaris cultured from grains.

Enhancements of Crystallization and Opto-Electrical performance of ZnO/Ti/ZnO Thin Films (ZnO/Ti/ZnO 박막의 결정성 및 전기광학적 완성도 개선 연구)

  • Jin-Kyu Jang;Yu-Sung Kim;Yeon-Hak Lee;Jin-Young Choi;In-Sik Lee;Dae-Wook Kim;Byung-Chul Cha;Young-Min Kong;Daeil Kim
    • Journal of Surface Science and Engineering
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    • v.56 no.2
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    • pp.147-151
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    • 2023
  • Transparent ZnO (100 nm thick) and ZnO/Ti/ZnO (ZTZ) films were prepared with radio frequency (RF) and direct current (DC) magnetron sputtering on the glass substrate at room temperature. During the ZTZ film deposition, the thickness of the Ti interlayer was varied, such as 6, 9, 12, and 15 nm, while the thickness of ZnO films was kept at 50 nm to investigate the effect of the Ti interlayer on the crystallization and opto-electrical performance of the films. From the XRD pattern, it is concluded that the 9 nm thick Ti interlayer showed some characteristic peaks of Ti (200) and (220), and the grain size of the ZnO (002) enlarged from 13.32 to 15.28 nm as Ti interlayer thickness increased. In an opto-electrical performance observation, ZnO single-layer films show a figure of merit of 1.4×10-11 Ω-1, while ZTZ films with a 9 nm-thick Ti interlayer show a higher figure of merit of 2.0×10-5 Ω-1.

Evaluation of Hydraulic Conductivity of Slurry-wall-type Vertical Cutoff Wall with Consideration of Filter Cake (필터케이크(filter cake)를 고려한 슬러리월 연직차수벽의 현장투수계수 평가)

  • Nguyen, The Bao;Lee, Chul-Ho;Choi, Hang-Seok;Kim, Sang-Gyun
    • Journal of the Korean Geotechnical Society
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    • v.24 no.11
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    • pp.121-131
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    • 2008
  • In constructing a slurry trench cutoff wall, bentonite-water slurry is used to secure the stability of sidewalls during excavation before the wall is completed by backfilling. Unexpectedly, a thin but relatively impermeable layer called filter cake can be formed on the excavation surface, which significantly influences the result of slug test analysis in the cutoff wall if not considered. This study is to examine the effect of filter cake on evaluating hydraulic conductivity of the vertical cutoff wall through slug test analysis with the aid of the verified numerical program Slug_3D. The no-flux boundary conditions were adopted in Slug_3D to simulate the filter cake on the interface between the wall and the natural soil. A new set of type curves were built for applying the type curve method. New modification factors were obtained for using the modified line-fitting method. With consideration of filter cake, the type curve method and the modified line-fitting method were adopted to reanalyze the case study taken from EMCON (1995). The previous results achieved by Choi and Daniel (2006) without consideration of filter cake were compared with the present results obtained in this paper. The comparison emphasizes the necessity of considering filter cake when analyzing slug test results in vertical cutoff walls.

The Effect of Dangguijakyak-san on Wound Healing (당귀작약산의 창상 회복에 대한 효과)

  • Yun-Jin Lee;Chang-Hoon Woo;Young-Jun Kim;Hyeon-Ji Kim;Hee-Duk An
    • Journal of Korean Medicine Rehabilitation
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    • v.33 no.3
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    • pp.47-65
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    • 2023
  • Objectives We evaluated the wound healing effects of Dangguijakyak-san (DJ) using C57BL/6 mice that were generated open wound. Methods The study was conducted with seven C57BL/6 mice assigned to each group, divided into the normal group, control group, vitamin E group, DJ low-dose group, DJ high-dose group. We measured total polyphenol, flavonoid contents, the size of the wound, liver function, pro-inflammatory cytokine activity in serum, inflammation-related proteins, adhesion molecules and chemokine proteins, collagen-related proteins in skin tissue and histopathological changes by H&E and Masson's staining. Results DJ treatment significantly reduced the area of the wound compared to the control group. Also, inflammatory cytokines were reduced and the expression of anti-inflammatory-related factors (interleukin-4 [IL-4] and IL-10) was significantly increased in the DJ treatment group. We identified that DJ treatment inhibits both pathways of inflammation, the mitogen-activated protein kinases and nuclear factor-κB pathway. Moreover, the protein expressions of Sirt1 (sirtuin 1), MCP-1 (monocyte chemoattractant protein 1), ICAM-1 (intercellular adhesion molecule 1), and VCAM-1 (vascular cell adhesion molecule 1) were decreased by DJ administration. Also, the expression of α-smooth muscle actin and collagen type I alpha 1, collagen-related proteins, that help skin recovery was significantly increased in the DJ treatment group. Histopathologically, a relatively thin epithelial layer could be observed in the DJ administration group, as well as an increase in fibroblasts and collagen fibers. Conclusions These data suggest that DJ treatment is effective in wound healing, suppressing inflammatory proteins, increasing skin repair factors and improving histopathological changes caused by wounds.

Elucidation of new anti-impotency analogue in food (식품 중 발기부전치료제 유사물질 규명)

  • Suh, Junghyuck;Choi, Jangduck;Park, Kunsang;Hu, Soojung;Yoon, Taehyung;Kim, Eunju;Han, Seungwoo;Kim, Sohee;Lee, Kwangho;Kwan, Sungwon;Kim, Deukjoon
    • Analytical Science and Technology
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    • v.22 no.4
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    • pp.345-353
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    • 2009
  • The new anti-impotency analogue was identified in food source. Detection of this analogue was accomplished through screening of food samples by liquid chromatography/photodiode array detector. The spectrum pattern of analogue compound was similar to that observed for hongdenafil which was analogue of sildenafil. This new compound was isolated and purified using the liquid-liquid extraction, thin layer chromatography, column chromatography and preparative HPLC. And then those structure were identified using analytical instruments such as HPLC/PDA, LC/MS/MS and NMR. The compound was given a name to oxohongdenafil which was replaced with acetyl oxoethylpiperazinyl residue instead of sulfonyl piperazine group of sildenafil. The regulation for the abovementioned analogue, oxohongdenafil, was established by Standard of Korean food code.