• Title/Summary/Keyword: KOH Solution

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Research on Process Technology of Molded Bridge Die on Substrate (MBoS) for Advanced Package (Advanced Package용 Molded Bridge Die on Substrate(MBoS) 공정 기술 연구)

  • Jaeyoung Jeon;Donggyu Kim;Wonseok Choi;Yonggyu Jang;Sanggyu Jang;Yong-Nam Koh
    • Journal of the Microelectronics and Packaging Society
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    • v.31 no.2
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    • pp.16-22
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    • 2024
  • With advances of artificial intelligence (AI) technology, the demand is increasing for high-end semiconductors in various places such as data centers. In order to improve the performance of semiconductors, reducing the pitch of patterns and increasing density of I/Os are required. For this issue, 2.5dimension(D) packaging is gaining attention as a promising solution. The core technologies used in 2.5D packaging include microbump, interposer, and bridge die. These technologies enable the implementation of a larger number of I/Os than conventional methods, enabling a large amount of information to be transmitted and received simultaneously. This paper proposes the Molded Bridge die on Substrate (MBoS) process technology, which combines molding and Redistribution Layer (RDL) processes. The proposed MBoS technology is expected to contribute to the popularization of next-generation packaging technology due to its easy adaption and wide application areas.

Characterization and Control of Vascellum curtisii (Berkeley)Kreisel Causing the Fairy Ring Arcs in the Golf Course in Korea (골프코스에서 페어리링의 원인이되는 Vascellum curtisii의 특징과 방계)

  • Choi, Dae-Hong;Lee, Jung-Han;Kim, Hee-Kyu
    • Asian Journal of Turfgrass Science
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    • v.22 no.2
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    • pp.171-178
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    • 2008
  • We have found the clusters of tiny spiny puffball-like mushrooms growing gregariously in fairy ring (arcs) rimmed by a zone of darker green grass in the golf courses. Macroscopic as well as microscopic characters were examined for the morphology of fruiting body. Exoperidium is thin and densely spiny with minute fibrillae at early stage. The connivent spines were soft and quite persistent. In age, the fibrillae scrumble away with a powdery coating, which leaves white endoperidium becoming pale brown. It's interior was white and fleshy at first, but turns into an olive-colored dust as the gleba, the spore-producing tissue, develops to maturity and loaded with olive-brown spore mass. Then, distinct apical pore developed on the endoperidium. Rudimentary subgleba(sterile base) was narrow, chambered, delineated from the gleba by a membrane in young material. These characters suggested this fungus is a Vascellum, a member of the family Lycoperdaceae. The shapes of the spores were globose, echinulate, $3{\sim}3.5{\mu}m$ in diameter, thick-walled, and olive brown. Capillitial threads were $8-9{\mu}m$ wide, mostly colorless in KOH solution and thin-walled, which designated as "paracapillitium". This is an another character that distinguishes this mushroom from Lycoperdon spp. The spines developed on exoperidium were characteristically connivent; their apices joined together in a point, leaving a space below, which gives the appearance of vault to each group of usually 5 to 6 fibrillae. Based on the above characters, this fungus is identified as Vascellum curtisii (Berkeley). The characters distinguishable this from Lycoperdon pulcherrimum, and Vascellum pretense are discussed in detail. Control trial was also attempted. Strong vertical raking(SVR) followed by applying 500x detergent solution (Spark, Aekyung Co. Seoul) resulted in excellent control over any other treatments. In this plot, fruiting body was not developed throughout the end of mushroom growing season.

The Si Microwire Solar Cell Fabricated by Noble Metal Catalytic Etching (Noble metal catalytic etching법으로 제조한 실리콘 마이크로와이어 태양전지)

  • Kim, Jae-Hyun;Baek, Sung-Ho;Choi, Ho-Jin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.278-278
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    • 2009
  • A photovoltaic device consisting of arrays of radial p-n junction wires enables a decoupling of the requirements for light absorption and carrier extraction into orthogonal spatial directions. Each individual p-n junction wire in the cell is long in the direction of incident light, allowing for effective light absorption, but thin in orthogonal direction, allowing for effective carrier collection. To fabricate radial p-n junction solar cells, p or n-type vertical Si wire cores need to be produced. The majority of Si wires are produced by the vapor-liquid-solid (VLS) method. But contamination of the Si wires by metallic impurities such as Au, which is used for metal catalyst in the VLS technique, results in reduction of conversion efficiency of solar cells. To overcome impurity issue, top-down methods like noble metal catalytic etching is an excellent candidate. We used noble metal catalytic etching methods to make Si wire arrays. The used noble metal is two; Au and Pt. The method is noble metal deposition on photolithographycally defined Si surface by sputtering and then etching in various BOE and $H_2O_2$ solutions. The Si substrates were p-type ($10{\sim}20ohm{\cdot}cm$). The areas that noble metal was not deposited due to photo resist covering were not etched in noble metal catalytic etching. The Si wires of several tens of ${\mu}m$ in height were formed in uncovered areas by photo resist. The side surface of Si wires was very rough. When the distance of Si wires is longer than diameter of that Si nanowires are formed between Si wires. Theses Si nanowires can be removed by immersing the specimen in KOH solution. The optimum noble metal thickness exists for Si wires fabrication. The thicker or the thinner noble metal than the optimum thickness could not show well defined Si wire arrays. The solution composition observed in the highest etching rate was BOE(16.3ml)/$H_2O_2$(0.44M) in Au assisted chemical etching method. The morphology difference was compared between Au and Pt metal assisted chemical etching. The efficiencies of radial p-n junction solar Cells made of the Si wire arrays were also measured.

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Changes in Major Constituents by Soaking of Acanthopanax koreanum with Spirit Solution (탐라오갈피의 침출 중 유용성분의 변화)

  • Lim, Ja-Hoon;Lee, Sang-Hyup;Jun, Bong-Soo;Yang, Young-Taek;Koh, Jeong-Sam
    • Applied Biological Chemistry
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    • v.48 no.2
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    • pp.166-172
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    • 2005
  • In order to prepare liqueur of Acanthopanax koreanum, changes in major constituents by soaking below 0.5 cm size dried sample 700 g in 10 l of $15{\sim}95%$ spirit solution for 70 days were investigated. Color b was increased according to lower ethanol concentration and longer soaking periods. Extract was increased gradually with soaking periods, and the content was $0.6{\sim}0.7%$ (w/v) with stem, $1.0{\sim}1.5%$ (w/v) with root. Eleutheroside B and E were extracted rapidly within 20 days of soaking, moreover were increased according to ethanol concentration within 15% to 70%. Acantoic acid was extracted rapidly $2.8{\sim}22.6\;{\mu}g/ml$ with stem, and $560{\sim}1,700\;{\mu}g/ml$ with root within 5 to 10 days. For preparation of liqueur of Acanthopanax koreanum, it is necessary to soak more portion of dried root with $60{\sim}80%$ ethanol concentration for $30{\sim}50$ days, and then to blend after aging for 13 weeks.

Preparation and Characterization of High Absorptive Cellulose Film Derived from Styela Clava Tunic for Wound Dressing (흡수성이 우수한 창상치료용 미더덕껍질 셀룰로오스필름의 제조 및 특성 분석)

  • Seong, Keum-Yong;Koh, Eun-Kyoung;Lee, Seunghyun;Kwak, Moon Hwa;Son, Hong Joo;Lee, Hee Seob;Hwang, Dae Youn;Jung, Young Jin
    • Textile Coloration and Finishing
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    • v.27 no.1
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    • pp.70-79
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    • 2015
  • To establish the optimal conditions for the manufacture of high absortive cellulose film(CF) originated from Styela clava tunic(SCT), the physicochemical properties included absorption was measured in CFs prepared under the various conditions. The highest absorption was observed for SCT-CF20 prepared from the cellulose solution dissolved at $80^{\circ}C$ for 20min, although the filtration treatment did not induce any significance alteration. Also, the absorption was higher in SCT-CF20-F prepared by the freeze drying than SCT-CF20-N(ambient air drying) and SCT-CF20-H(heat drying). The addition of porogen($NaHCO_3$) induced an increase of absorption in SCT-CF20-PF relative to SCT-CF20-F, while the number of interconnected porous structures was enhanced in SCT-CF20-PF. Furthermore, a high level of SK-MEL-2 cells viability was observed in SCT-CF20-PN and SCT-CF20-PF cultured group. These results show that SCT-CF may have high absorption and biocompatibility when prepared from SCT cellulose solution dissolved at $80^{\circ}C$ for 20min after addition of porogen and then subjected to freeze drying.

Effect of Hypochlorous Acid to Reduce Microbial Populations in Dipping Procedure of Fresh Produce as Saengshik Raw Materials (생식원료 야채의 전처리공정에서 Hypochlorous Acid의 미생물 제어 효과)

  • Koh, So-Mi;Kim, Jeong-Mok
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.39 no.4
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    • pp.637-642
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    • 2010
  • Pre-treatment steps of fresh produce as Saengshik raw materials are followed by initial clean-up, dipping, primary washing, and cutting. Hypochlorous acid solution was applied in the dipping step to reduce natural microflora. Also, procedures were changed by cutting, dipping and then primary washing, and the efficacy of hypochlorus acid was evaluated. Potatoes, carrots, kales, and angelicas were submerged in water or 100 ppm of hypochlorous acid for 5 min. After initial clean-up, the aerobic plate counts of potatoes, carrots, kales and angelicas were 4.7, 5.3, 5.6, and 5.7 log CFU/g, respectively. When samples were submerged into water, it only reduced the population of natural microflora by 0.2 to 1.1 log CFU/g, whereas when treated with hypochlorous acid, it reduced the population by 0.5 to 2.8 log CFU/g. Reductions of natural microflora in green leafy vegetables were more highly achieved than bulbs such as potatoes and carrots. However, the numbers of natural microflora were increased after cutting step. To control the cross contamination at the cutting process, the process was changed as follows: initial clean-up, cutting, dipping in hypochlorous acid, and then primary washing. It showed effective reduction of the population by 2.3 to 3.2 log CFU/g. Hypochlorous acid solution could be useful as a sanitizer for surface washing of fresh vegetables.

Microemulsions in Supercritical Carbon Dioxide Utilizing Nonionic Surfactants (초임계 이산화탄소내 비이온성 계면활성제를 이용한 마이크로에멀젼 형성연구)

  • Koh, Moonsung;Yoo, Jaeryong;Park, Kwangheon;Kim, Hongdoo;Kim, Hakwon
    • Clean Technology
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    • v.10 no.4
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    • pp.221-228
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    • 2004
  • Ethoxylated Nonyl Phenol Series (NP-series), nonionic surfactants, were applied for forming microemulsions in supercritical $CO_2$. Measurement results of the solubility in supercritical $CO_2$ are in the following; NP-series were high soluble in carbon dioxide in spite of the fact that those were not $CO_2$-philic surfactants traditionally well known. Water in $CO_2$ microemulsions were also formed stably. A complexation of hydrophilic lengths for $CO_2$-philic parts of NP-Series surfactants was optimized by NP-4 surfactant(N=4) for forming the microemulsions through the experiments. Formation of microemulsions was confirmed by measuring the UV-Visible spectrum through a spectroscopic method and existence of water in the microemulsions was confirmed as well. In order to apply it for a metal surface treatment or electroplating, an experiment for forming acid(organic, inorganic) solution in $CO_2$ microemulsions was carried out. Ionic surfactant in the reaction to an acid solution became unstable to form microemulsions, however, nonionic surfactant was formed stably in the reaction. Results of the study will be utilized for expanding the application scope of supercritical $CO_2$ which is an environmental-friendly solvent.

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A Study in Preparation of $^{113m}In$ colloid as Scanning Agent and it's Organ Distribution in Rats (주사용(走査用) $^{113m}In$ 교질(膠質)의 조제(調製) 및 흰쥐에서의 장기분포(臟器分布)에 관(關)한 연구(硏究))

  • Koh, Chang-Soon;Rhee, Chong-Heon;Chang, Ko-Chang;Hong, Chang-Gi D.
    • The Korean Journal of Nuclear Medicine
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    • v.3 no.1
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    • pp.73-82
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    • 1969
  • The newly developed diagnostic method with application of $^{113}Sn-^{113m}In$ cow system ($^{113}Sn:\;T\frac{1}{2}$ 118 days, $^{113m}In:\;T\frac{1}{2}$ 1.7 hrs, 390 Kev, Single ${\gamma}$) has the remarkable advantages such as increased diagnostic ability by single large dose administration of $^{113m}In$ with no subsequent radiation hazard and shortened examining time. We reformed the research of following scope with the use of developed $^{113}Sn-^{113m}In$ cow (25 mCi) generator: The sizes of particles produced under various conditions were investigated, and possibility for application to the scannings of various organs such as brain, liver, lung, bone marrow and blood pool etc. were studied. Results: $^{113m}InCl_3$ solution eluted from diluted HCl solution (pH 1.5) passed through $^{113}Sn-^{113m}In$ generator, and there can be produced various sized particles of colloidal indium. And there observed the state of distribution of $^{113m}In$ in each organ which showed many differences according to the particle sizes of colloidal indium. The results are stated as follows: 1. The adjustment of pH is the most important factor in making the desirable particle size of colloidal indium. The colloid for blood pool showed the highest level as 7.1%/gm blood, at pH 1.7, the colloid of pH 3.5 for liver scanning showed the highest level, 88.4%, in the liver, the colloid pH 6 showed the highest level, 3.1%, in the spleen, and the colloid of pH 11.0 showed the highest level, 85.3%/gm, in the lung. 2. The colloid for liver scanning made with NaCl-NaOH system showed the highest liver uptake at pH 7.2, and at either higher or lower pH than 7.2 showed decrease of liver uptake more or less. 3. The activity of $^{113m}In$ eluted through $^{113}Sn-^{113m}In$ generator indicated over 90% in the initial 4 ml, and particularly 88.1%-86.0% in the initial 2 ml. 4. The incubation time, tempertaure and mechanical irritation related to colloid formation and coating of colloid were not the definite condition of influence.

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Element Dispersion and Wallrock Alteration of TA26 Seamount, Tonga Arc (통가열도 TA26 해저산의 모암변질과 원소분산)

  • Yoo, Bong-Chul;Choi, Hun-Soo;Koh, Sang-Mo
    • Economic and Environmental Geology
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    • v.44 no.5
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    • pp.359-372
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    • 2011
  • TA26 seamount, which is located at south part of Tonga arc, occurs widely hydrothermal plume and is area that sampled hostrock, hydrothermal ore and hydrothermal alteration rock for this study. Hostrocks are basalt and basaltic andesite. Altered rocks by hydrothermal solution consists of plagioclase, pyroxene, pyrite, ilmenite, amorphous silica, barite, smectite, iron sulfates, Fe-Si sulfates and Fe silicates. Gains and losses of major, trace and rare earth elements during wallrock alteration suggest that $K_2O$(+0.04~+0.45 g), $SiO_2$(-6.52~+10.56 g), $H_2O$(-0.03~+6.04 g), $SO_4$(-0.46~+17.54 g), S(-0.46~+13.45 g), total S(-0.51~+16.93 g), Ba(-7.60~+185078.62 g), Sr(-36.18~+3033.08 g), Ag(+54.83 g), Au(+1467.49 g), As(-5.80~+1030.80 g), Cd(+249.78 g), Cu(-100.57~+1357.85 g), Pb(+4.91~+532.65 g), Sb(-0.32~+66.59 g), V(-113.58~+102.94 g) and Zn(-49.56~+14989.92 g) elements are enriched from hydrothermal solution. Therefore, gained(enriched) elements(($K_2O$, $H_2O$, $SO_4$, S, total S, Ba, Sr, Ag, Au, As, Cd, Cu, Pb, Sb, V, Zn) represent a potentially tools for exploration of sea-floor hydrothermal deposits from the Tonga arc.

A Study for Recoverability of Iron Resource in Red Mud (레드머드 내 철 자원 회수 가능성 고찰)

  • Kim, Bong-Ju;Kwon, Jang-Soon;Koh, Yong-Kwon;Park, Cheon-Young
    • Economic and Environmental Geology
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    • v.53 no.3
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    • pp.297-306
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    • 2020
  • The red mud generated from bauxite during the Bayer alumina production process has been regarded as an industrial waste due to the high alkaline property and high content of Na. Despite of its environmental problem, various studies for recovery of the valuable resources from red mud has been also carried out because of high content (25.7 wt.% as Fe2O3 in this study) of iron in red mud. In order to recover the iron resource in the red mud, microwave heating experiments were performed with adding of activated carbon and elemental sulfur to the red mud. Through the microwave heating the powdered red mud mixtures converted to porous and vitrified solid aggregates. The vitrified aggregates produced by microwave heating are composed of goethite, zero valent iron (Fe0), pyrrhotite and pyrite. And then, the microwave heating samples were dissolved in the aqua regia solution, and Fe precipitates were obtained as a Fe-chlorides by adding of NaCl salt in the aqua regia solution. The Fe recovery rates in the Fe-chloride precipitates showed differences depending on the experimental mixture conditions, and Fe grades of the end products are 49.0 wt.%, 58.0 wt.% and 59.5 wt.% under mixture conditions of red mud, red mud + activated carbon, and red mud + activated carbon + elemental S, respectively. The Fe content of 56.0 wt.% is generally known as the grade value of Fe in a iron ore for iron production, and the Fe grades of microwave heating samples with adding activated carbon and elemental S in this study are higher than the grade value of 56.0 wt.%.