• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.227-227
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• 2012

Cryopump는 반도체 임플란타 공정, OLED분야, 신소재 개발, 표면분석 및 처리, 의료분야, 입자가속기, 핵융합 등 다양한 진공분야에 응용되는 고진공용 극저온펌프이다. 특히 향후로의 산업구조는 디스플레이, 반도체, IT 산업분야로 집중 재편될 것이기에, 이에 따른 핵심제조장비인 고진공 펌프의 수요가 급증할 것으로 판단된다. 그리고 이를 위한 핵심부품과 장비들의 국산화가 시급한 실정이다. 기술적인 측면에서 보자면 GVT는 미국의 Varian과 일본Ebara의 Cryopump 제조기술을 원천으로 한 회사로써 현재는 국내 유일의 G-M냉동기와 Cryopump 제조기술을 보유한 업체이다. 그리고 최근 오랫동안 정체되었던 관련 기술을 발전시켜 최적화된 한국형 G-M 냉동기 및 이를 장착한 다양한 사이즈의 고성능 Cryopump를 출시하게 되었다. 가장 큰 수확은 Cryopump의 성능을 크게 향상시켰으며 무엇보다 고객맞춤형으로 디자인할 수 있을 정도의 기술력을 확보하게 되었다는 점이다. Cryopump의 성능은 장착되는 Cryocooler(G-M냉동기)의 성능과 밀접한 관련이 있기 때문에 일차로 Cryocooler의 성능을 개선하고 이차로 이를 장착한 Cryopump의 성능을 개선하였다. 본 연구는 일차로 진행된 HP Series 2단 Cryocooler 4가지 모델 중 가장 범용인 HPM 모델과 HPS모델에 대한 제작과 성능시험에 관한 것이다. 이는 각각 기존의 ICP Series 펌프에 장착되던 Expander 535 모델 및 Expander 855 모델에 대한 설계 최적화의 결과물로써 내용은 Cryocooler에 대한 'Typical Performance Test(1st STG와 2nd STG의 온도가 각각의 Stage에 인가되는 Heat Load에 의해 그물망 형태의 그래프가 되도록 수행하는 시험법)'의 절차를 따라 수행되었다. HPM Cryocooler의 성능은 2nd STG Temp. 20K 와 1st STG Temp. 80K를 Heat Load 기준으로 하였을 경우, 각각 8.2W, 55.0W의 성능을 나타내었고 HPS Cryocooler의 성능은 2nd STG Temp. 20K 와 1st STG Temp. 72K를 Heat Load기준으로 하였을 경우, 각각 14.0W, 90.0W의 성능을 나타내었다. 1st STG Temp.를 72K로 정한 이유는 Power Supply의 용량 한계로 인해 90W이상의 Heat Load를 인가할 수 없었기 때문이다. 만약 성능 그래프의 경향성을 고려하여 1st STG Temp. 80K로 가정한다면, 각각 약 13W, 100W 정도의 성능을 가질 것으로 추정된다. 단, 본 시험에 사용된 Compressor는 GVT의 HC80Plus 모델로 내부에는 Helium용 5HP급 Scroll Type의 Compressor가 장착되어 있으며, 봉입압력 250Psig에 저압 100Psig기준, 65scfm의 유량을 가지는 압축기이다. 압축기와 Cryocooler의 조합은 1:1이었고 시험방법은 Cryocooler에 대한 GVT 자체규정에 따라 진행되었으며 밤과 낮 및 공장전체의 부하변동에 따른 냉각수 온도변화에 따른 펌프의 성능변화는 고려되지 않았다.

• Journal of the Korean Dietetic Association
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• v.16 no.2
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• pp.116-121
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• 2010

Minerals play an important role in the body as essential nutrients. However, it is not easy to meet DRIs because food sources of minerals are limited. Recently, consumption of bottled natural water has been increasing in Korea due to water pollution and distrust of tap water. The present study was conducted to investigate mineral contents in bottled natural water and their intakes among Korean adults. We analyzed eight minerals in seven kinds of bottled natural water by ICP-spectrometry and conducted a survey on the intake status of water and bottled natural water with 400 Korean young adults. The mean contents of Ca, Mg, Fe, Zn, Cu, Mn, Se, and Mo in bottled natural water were 22.45${\pm}$22.48 mg/L, 10.59${\pm}$9.97 mg/L, 0.27${\pm}$0.18 ${\mu}g/L$, 2.06${\pm}$1.48 ${\mu}g/L$, 5.47${\pm}$0.70 ${\mu}g/L$, 1.43${\pm}$0.37 ${\mu}g/L$, 1.90${\pm}$0.96 ${\mu}g/L$, and 3.34${\pm}$0.79 ${\mu}g/L$, respectively. The mean age, height, weight, and BMI were 22.76 years, 174.94 cm, 68.64 kg, and 22.41 $kg/m^2$ for males (n=150) and 21.25 years, 162.04 cm, 51.05 kg, and 19.46 $kg/m^2$ for females (n=250), respectively. The respective daily intakes of total water and bottled natural water as water itself were 670.30 ml and 212.20 ml for males and 488.04 ml and 132.72 ml for females. The daily intakes of Ca, Mg, Fe, Zn, Cu, Mn, Se, and Mo from bottled natural water were 4.76 mg, 2.25 mg, 0.06 ${\mu}g$, 0.44 ${\mu}g$, 1.16 ${\mu}g$, 0.30 ${\mu}g$, 0.40 ${\mu}g$, and 0.71 ${\mu}g$ for males and 2.98 ${\mu}g$, 1.41 mg, 0.04 ${\mu}g$, 0.27 ${\mu}g$,0.73 ${\mu}g$, 0.19 ${\mu}g$,0.25 ${\mu}g$, and 0.44 ${\mu}g$ for females, respectively. Overall, the contents of Ca, Mg, and Se in bottled natural water were relatively high and the daily intakes of these minerals were 0.4~1.0% of the DRIs.

• Economic and Environmental Geology
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• v.42 no.1
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• pp.27-53
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• 2009

A 30-m-thick Middle Ordovician Jigunsan Shale exposed along the southern limb of the Backunsan (Baekunsan) Syncline, Taebacksan (Taebaeksan) basin, has been simply considered as a transgressive shale sequence onlapped the underlying Maggol platform carbonates. Results of this study, however, suggest that majority of the Jigunsan Shale be interpreted as a regressive shale sequence downlapped onto a thin (ca. 240 cm) marine stratigraphic unit consisting of organic-rich (>3 wt.% of TOC) black shales in the lower Jigunsan Shale, which was accumulated at the time of maximum regional transgression. Detailed stratigraphic analysis in conjunction with XRD, XRF, and ICP-MS as well as Rock-Eval pyrolysis allows the thin marine stratigraphic unit in the Jigunsan Shale to define a condensed section that was deposited in a distinctive euxinic zone formed due to expansion of pycnocline during the early highstand phase. As well, a number of stratigraphic horizons of distinctive character that may have sequence stratigraphic or environmental significance, such as transgressive surface, maximum flooding surface, maximum sediment starvation surface, and downlap surface, are identified in the lower Jigunsan Shale. In the future, these stratigraphic horizons will provide very useful information to make a coherent regional stratigraphic correlation of the Middle Ordovician strata and to develop a comprehensive understanding on stratigraphic response to tectonic evolution as well as basin history of the Taebacksan Basin.

• Korean Journal of Environmental Agriculture
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• v.38 no.2
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• pp.96-103
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• 2019

BACKGROUND: This study was conducted to develop selenium (Se)- and germanium (Ge)-enriched rice by foliar spray application of organic or inorganic Se and Ge. METHODS AND RESULTS: The time and frequency of organic or inorganic Se and Ge treatment were performed at the five main growth stages as followings: effective tillering stage (E), maximum tillering stage (M), booting stage (B), heading stage (H), grain filling stage (G). The main treatment plots were consisted of (1) 'once' treatment (at each E, M, B, H, G stage, Se/Ge single apply), (2) 'twice I' (at H + G stages, organic or inorganic Se/Ge apply), (3) 'twice II' (at H + G stages, mixture apply of Se + Ge + pesticide). The organic or inorganic Se treatment concentration was 20 and 40 ppm, and the Ge was 50 and 100 ppm. The Se and Ge contents in rice grain (brown rice and polished rice) were analyzed by inductively coupled plasma (ICP). The highest Se content was noted in brown rice 'twice I' with Se 40 ppm (1394.06) at H + G stages, but the lowest was in 'once' with Se 40 ppm ($367.79{\mu}g{\cdot}kg^{-1}$) at B stage. The highest of Se content in polished rice was found in 'twice I' of Se 40 ppm (1090.25) at H + G stages, but the lowest was in 'once' with Se 40 ppm ($403.53{\mu}g{\cdot}kg^{-1}$) at E stage. On the other hand, The highest of Ge content in brown rice was found in 'twice I' with Ge 100 ppm (398.66) at H + G stages, but the lowest was in 'once' with Ge 100 ppm ($139.64{\mu}g{\cdot}kg^{-1}$) at B stage. The highest of Ge content in polished rice was found in 'twice I' of Ge 100 ppm (300.29) at H + G stages, but the lowest was in 'once' with Ge 100 ppm ($142.24{\mu}g{\cdot}kg^{-1}$) at B stage. CONCLUSION: Se and Ge contents both in brown rice and polished rice treated with organic Se and Ge forms were higher than those of inorganic Se and Ge. Overall results concluded that the supplementation of organic Se and Ge contents in brown and polished rice contents were comparatively higher than the inorganic Se and Ge. This is results also proved that the foliar spray application of organic Se and Ge has positive nutritive effect on the rice for regular consumption.

• Clean Technology
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• v.26 no.4
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• pp.270-278
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• 2020

Palladium (Pd) has been widely used in various industrial applications such as jewelry, catalyst, and dental materials despite its limited resources. It has been gaining attention to recover Pd with high purity from the spent materials. This study investigated the optimum conditions for the leaching and recovery of metallic Pd. The leaching parameters are HCl concentration, temperature, time, concentration of oxidants, and pulp density. 97.2% of Pd leaching efficiency was obtained in 3 M HCl with 3 vol% oxidants at 80℃ for 60 min. The ratio of hydrogen peroxide to sodium hypochlorite played a critical role in the leaching efficiency due to the supply of Cl- ions in the leachate. Moreover, the complete recovery of Pd in the leachate was achieved at 80℃ with 0.3 formic acid/leachate after adjusting the pH value of 7. This situation was ascribed to the decomposition of formic acid into hydrogen gas and carbon dioxide at 80℃. ICP-AES and XRD characterized the recovered Pd powder, and the purity of the recovered powder was found to be 99.6%. Consequently, the recovered Pd powder with high purity could be used in circuits, catalyst precursors, and surgical instruments.

• Journal of the Korean Wood Science and Technology
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• v.35 no.1
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• pp.73-80
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• 2007

This study was carried out to separate the heavy toxic metals in eco-building materials by low-temperature pyrolysis, especially arsenic (As) compounds in CCA wood preservative as a solid in char. The pyrolysis was carried out to heat the CCA-treated Hemlock at $280^{\circ}C$, $300^{\circ}C$, $320^{\circ}C$, and $340^{\circ}C$ for 60 mins. Laboratory scale pyrolyzer composed of [preheater$\rightarrow$pyrolyzer$\rightarrow$1st water scrubber$\rightarrow$2nd bubbling flask with 1% $HNO_3$ solution$\rightarrow$vent], and was operated to absorb the volatile metal compound particulates at the primary water scrubber and the secondary nitric acid bubbling flask with cooling condenser of $4^{\circ}C$ under nitrogen stream of 20 mL/min flow rate. And the contents of copper, chromium and arsenic compounds in its pyrolysis such as carbonized CCA treated wood, 1st washing and 2nd washing liquors as well as its raw materials, were determined using ICP-AES. The results are as follows : 1. The yield of char in low-temperature pyrolysis reached about 50 percentage similar to the result of common pyrolytic process. 2. The higher the pyrolytic temperature was, the more the volatiles of CCA, and in particular, the arsenic compounds were to be further more volatile above $320^{\circ}C$, even though the more repetitive and sequential monitorings were necessary. 3. More than 85 percentage of CCA in CCA-treated wood was left in char in such low-temperature pyrolytic condition at $300^{\circ}C$. 4. Washing system for absorption of volatile CCA in this experiment required much more contacting time between volatile gases and water to prevent the loss of CCA compounds, especially the loss of arsenic compound. 5. Therefore, more complete recovery of CCA components in CCA-treated wood required the lower temperature than $320^{\circ}C$, and the longer contacting time of volatile gases and water needed the special washing and recovery system to separate the toxic and volatile arsenic compounds in vent gases.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.2
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• pp.203-214
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• 2014

We measured the contact dermatitis-causing substances concentrations in 28 commercial oxidative hair-coloring products. This study was aimed to provide the fundamental data about oxidative hair-coloring products. We selected 10 oxidation dyes (p-phenylenediamine, toluene-2,5-diamine, m-phenylenediamine, nitro-p-phenylenediamine, p-aminophenol, m-aminophenol, o-aminophenol, p-methylaminophenol, N,N'-bis(2-hydroxyethyl)-p-phenylenediamine sulfate, 2-methyl-5-hydroxyethylaminophenol) and 4 heavy metal (nikel; Ni, chromium; Cr, cobalt; Co, copper; Cu) as contact dermatitis-causing substances. To identify 10 oxidation dyes, hexane-2% sodium sulfite was used for the rapid and simple extraction and ultra performance liquid chromatography (UPLC) analysis was used for simultaneous analysis in 12 minutes. 10 oxidative dyes were detected as indicated on the product packaging and each concentration was lower than prescribed upper concentration limit by pharmaceutical manufacturing standards. And we analysed inductively coupled plasma-optical emission spectrophotometer (ICP-OES) for content search of heavy metal after microwave digestion. The heavy metal average concentration in oxidative hair-coloring products was 0.572 ${\mu}g/g$ for Ni, 3.161 ${\mu}g/g$ for Cr, 2.029 ${\mu}g/g$ for Co, 0.420 ${\mu}g/g$ for Cu, respectively. The average of concentration in powder type (henna) was higher than those of other foam and cream type oxidative hair-coloring products as follows; 1.800 ${\mu}g/g$ for Ni, 10.127 ${\mu}g/g$ for Cr, 7.082 ${\mu}g/g$ for Co, 1.451 ${\mu}g/g$ for Cu. Hair coloring products were classified into the six colors - black, dark brown, brown, dark brown, light brown, red brown and analyzed. Brown color had the highest average concentration of Co and the others had the highest average concentration of Cr.

• Korean Journal of Environmental Agriculture
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• v.23 no.1
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• pp.15-21
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• 2004

Objectives of this study were to monitor the distribution of heavy metals, to compare extractable heavy metal with total content and to investigate the relationships between soil physico-chemical properties and heavy metals in orchard soil. Sampling sites were 48 in Gyeonggi, 36 in Gangwon, 36 in Chungbuk, and 44 in Chungnam, Soils were collected farm form two depths, 0 to 20 and 20 to 40 cm (here after referred to as upper and lower layers) from March to May in 1998. Total contents of heavy metal in soils were analyzed by ICP-OES after acid digestion ($HNO_3$:HCl:$H_2O_2$) whereas extractable contents were measured after successive extraction of 0.1N-HCl, 0.05 M-EDTA, and 0.005 M-DTPA. Mercury was analysed by mercury atomizer. The average contents of Cd Cu, and Pb in the extractant with 0.1N-HCl at upper layer were 0.080, 4.23, and 3.42 mg/kg, respectively. As content in the extractant with 1N-HCl was 0.44 mg/kg, and total contents of Zn, Ni and Hg were 78.9, 16.1, and 0.052 mg/kg, respectively. The ratios of concentrations of heavy metals to threshold values (Cd 1.5, Cu 50, Pb 100, Zn 300, Ni 40, Hg 4 mg/ke in Soil Environmental Conservation Act in Korea (2001) were low in the range of $1/2.5{\sim}1/76.9$ in orchard soils. The ratios of extractable heavy metal to total content ranged $5.4{\sim}9.21%$ for Cd, $27.9{\sim}47.8%$ for Cu, $12.6{\sim}21.8$% for Pb, $15.8{\sim}20.3%$ for Zn, $5.3{\sim}6.3%$ for Ni, and $0.7{\sim}3.6%$ for Zn, respectively. Cu and Pb contents in 0.05 M-EDTA extractable solution were higher than those in the other extractable solution. Total contents of Cd, Ni and Ni in soils were negatively correlated with sand content but positively correlated with silt and clay contents. Ratios of extractable heavy metal to total content were negatively correlated with clay content but ai and Ni contents were positively correlated with soil pH, organic matter, and available phosphorous. Therefore, the orchard soil was safe because the heavy metal contents of orchard soil were very low as compared to its threshold value in the Soil Environmental Conservation Act. However, it need to consider the input of agricultural materials to the agricultural land for farming practices for assessment of heavy metals.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.1-33
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• 1997

The objective of this study was to analyze the in vitro and in vivo corrosion products of low and high copper amalgams. The four different types of amalgam alloy used in this study were Fine cut, Caulk spherical, Dispersalloy, and Tytin. After each amalgam alloy and Hg were triturated according to the directions of the manufacturer by means of the mechanical amalgamator(Amalgam mixer. Shinhung Co. Korea), the triturated mass was inserted into a cylindrical metal mold which was 12mm in diameter and 10mm in height. The mass was condensed by 150Kg/cm compressive force. The specimen was removed from the mold and aged at room temperature for about seven days. The standard surface preparation was routinely carried out by emery paper polishing under running water. In vitro amalgam specimens were potentiostatically polarized ten times in a normal saline solution at $37^{\circ}C$(potentiostat : HA-301. Hukuto Denko Corp. Japan). Each specimen was subjected to anodic polarization scan within the potential range -1700mV to+400mV(SCE). After corrosion tests, anodic polarization curves and corrosion potentials were obtained. The amount of component elements dissolved from amalgams into solution was measured three times by ICP AES(Inductive Coupled Plasma Atomic Emission Spectrometry: Plasma 40. Perkim Elmer Co. U.S.A.). The four different types of amalgam were filled in occlusal and buccal class I cavities of four human 3rd molars. After about five years the restorations were carefully removed after tooth extraction to preserve the structural details including the deteriorated margins. The occlusal surface, amalgam-tooth interface and the fractured surface of in vivo amalgam corrosion products were analyzed. In vivo and in vitro amalgam specimens were examined and analyzed metallographically by SEM(Scanning Electron Microscope: JSM 840. Jeol Co. Japan) and EDAX(Energy Dispersive Micro X-ray Analyser: JSM 840. Jeol Co. Japan). 1. The following results are obtained from in vitro corrosion tests. 1) Corrosion potentials of all amalgams became more noble after ten times passing through the in vitro corrosion test compared to first time. 2) After times through the test, released Cu concentration in saline solution was almost equal but highest in Fine cut. Ag and Hg ion concentration was highest in Caulk spherical and Sn was highest in Dispersalloy. 3) Analyses of surface corrosion products in vitro reveal the following results. a)The corroded surface of Caulk spherical has Na-Sn-Cl containing clusters of $5{\mu}m$ needle-like crystals and oval shapes of Sn-Cl phase, polyhedral Sn oxide phase. b)In Fine cut, there appeared to be a large Sn containing phase, surrounded by many Cu-Sn phases of $1{\mu}m$ granular shapes. c)Dispersalloy was covered by a thick reticular layer which contained Zn-Cl phase. d)In Tytin, a very thin, corroded layer had formed with irregularly growing Sn-Cl phases that looked like a stack of plates. 2. The following results are obtained by an analysis of in vivo amalgam corrosion products. 1) Occlusal surfaces of all amalgams were covered by thick amorphous layers containing Ca-P elements which were abraded by occlusal force. 2) In tooth-amalgam interface, Ca-P containing products were examined in all amalgams but were most clearly seen in low copper amalgams. 3) Sn oxide appeared as a polyhedral shape in internal space in Caulk spherical and Fine cut. 4) Apical pyramidal shaped Sn oxide and curved plate-like Sn-Cl phases resulted in Dispersalloy. 5) In Tytin, Sn oxide and Sn hydroxide were not seen but polyhedral Ag-Hg phase crystal appeared in internal space which assumed a ${\beta}_l$ phase.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.3
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• pp.530-539
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• 2003

The aim of this study was to evaluate the resistance to degradation of four commercial composite resins in an alkaline solution. The brands studied were Charisma, Filtek P 60, Palpique Estelite, and Spectrum. Preweighed discs of each brand were exposed to 0.1N NaOH solution at $60^{\circ}C$. After 2 weeks they were removed, neutralized with HCl, washed with water and dried. Resistance to degradation was evaluated on the basis of following parameters: (a) mass loss(%) - determined from pre-and post-exposed specimen weights; (b) Si loss(ppm) - obtained from ICP-AE analysis of solution exposed to specimens; and (c) degradation depth(${\mu}m$) - measured SEM and CLSM from polished circular sections of exposed specimens. The results were as follows: 1. The sequence of mass loss was in descending order by Palpique Estelite, Filtek P 60, Charisma, and Spectrum. 2. The sequence of the degree of degradation layer depth was in descending order by Filtek P 60, Charisma, Palpique Estelita, and Spectrum. 3. The sequence of the Si loss was in descending order by Chrisma, Spectrum, Palpique Estelite, and Filtek P 60. 4. The correlation coefficient between mass loss and degradation layer depth was relatively high(r=0.704, p<0.05). 5. When observed with SEM, destruction of bonding was observed between resin matrix and filler. 6. When observed with CLSM, degradation layer depth of composite resin surface was observed.