• Bulletin of the Korean Chemical Society
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• 제20권9호
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• pp.1040-1044
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• 1999

A micro porous PTFE membrane desolvator (MMD) was built and evaluated for the on-line removal of organic solvents to facilitate the determination of trace metal contaminants in the solvents by ICP-AES. Three organic solvents, isopropyl alcohol (IPA), methanol, and dimethy sulfoxide (DMSO) were studied. The MMD reduced organic solvent concentration in the sample aerosol stream by 82% to 89%, as indicated by monitoring C(I) emission. Net signal intensity of Fe, Al, and Cu was increasing with higher organic solvent concentration, with the rate of increase being solvent dependent. The signal intensities for Mg and Pb followed the trend with the C(I) signal. Changing the sweep gas flow rate affected the optimum signal intensity. Wine samples were analyzed by the method of standard addition. The concentrations of B, Al, and Mg were determined with a relative precision of less than 2.3%.

• Applied Microscopy
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• 제24권3호
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• pp.87-93
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• 1994

In order to elucidate the machinability of lead brass, orthogonal machining experiment was conducted in SEM(Scanning Electron Microscope) equipped with a micro-machining device at a cutting speed of $7{\mu}m/s$ for brass containing 0.2 to 3wt% Pb. The microfactors (i.e., shear angle, contact length between chip and tool) were determined by in-situ observations. Machinability of brass containing lead is discussed in terms of the microfactors and the cutting resistant force tested by lathe cutting. The dynamic behavior of the chip formation of lead brass during the machining process was examined: The chips of lead brass form as a shear angle type. The shear angle increases with the content of lead in (6:4) brass. The pronounced effect of lead on the contact length between chip and tool was observed above 1% Pb. The cutting resistant force tested by lathe decreases remarkably with the lead content in brass. The observed microfactors are in close relation to the tested resistant force in macromachining.

• 한국재료학회지
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• 제5권2호
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• pp.178-183
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• 1995

본 연구에서는 상온에서 정방성 조성인 $Pb_{0.9888}Sr_{0.012}(Zr_{0.52}Ti_{0.48})O_{3}$계 세라믹스를 소결 후 직류전계 및 코로나를 이용하는 방법으로 소결시편을 분극한 후 분극방법에 따른 시편의 압전특성을 조사하였으며, 열화현상을 평가하기 위한 방법으로 시편의 내부응력의 차이를 조사하였다. 이 결과 코로나 분극방법은 직류분극에 비하여 $30^{\circ}C$정도 저온에서도 최대 Kp값을 얻을 수 있었으며 열화현상이 천천히 진행되었고 절연파괴가 발생하지 않는 등의 장점이 관찰되었다. 그러나 Kp값은 직류분극의 경우가 코로나 분극에 비하여 약 9~10%정도 높은 값을 나타내었다.

• Nuclear Engineering and Technology
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• 제53권8호
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• pp.2661-2668
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• 2021

Gamma radiation shielding features for three series of binary alloys identified as (Pb-Sn), (Pb-Zn), and (Zn-Sn) have been investigated. The mass attenuation coefficients (µ/ρ) for the selected alloys were simulated using the MCNP-5 code in the energy range between 0.01 and 15 MeV. Moreover, the (µ/ρ) values were computed using WinXCOM database in the same energy range to validate the simulation results. Results reveal a good agreement between the simulated and computed values. The half value layer (HVL), mean free path (MFP), effective atomic number (Z_eff) and exposure buildup factor (EBF) were evaluated for the selected binary alloys. Results showed that the PS1, PZ1, and ZS2 alloys have the best shielding parameters and better than the commercially standard and available radiation shielding materials. Therefore, the investigated alloys can be used as effective radiation shielding materials against gamma ray with energies between 0.01 and 15 MeV.

• Journal of Periodontal and Implant Science
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• 제53권6호
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• pp.429-443
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• 2023

Purpose: The aim of this study was to determine 1) the bone-regenerative effect of porcine bone block materials with or without collagen matrix incorporation, 2) the effect of a collagen barrier, and 3) the effect of adding recombinant human bone morphogenetic protein-2 (rhBMP-2) to the experimental groups. Methods: Four treatment modalities were applied to rabbit calvaria: 1) deproteinized bovine bone mineral blocks (DBBM), 2) porcine bone blocks with collagen matrix incorporation (PBC), 3) porcine bone blocks alone without collagen matrix incorporation (PB), and 4) PBC blocks covered by a collagen membrane (PBC+M). The experiments were repeated with the addition of rhBMP-2. The animals were sacrificed after either 2 or 12 weeks of healing. Micro-computed tomography (micro-CT), histologic, and histomorphometric analyses were performed. Results: Micro-CT indicated adequate volume stability in all block materials. Histologically, the addition of rhBMP-2 increased the amount of newly formed bone (NB) in all the blocks. At 2 weeks, minimal differences were noted among the NB of groups with or without rhBMP-2. At 12 weeks, the PBC+M group with rhBMP-2 presented the greatest NB (P<0.05 vs. the DBBM group with rhBMP-2), and the PBC and PB groups had greater NB than the DBBM group (P>0.05 without rhBMP-2, P<0.05 with rhBMP-2). Conclusions: The addition of rhBMP-2 enhanced NB formation in vertical augmentation using bone blocks, and a collagen barrier may augment the effect of rhBMP-2.

• 한국환경농학회지
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• 제35권1호
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• pp.79-86
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• 2016

본 연구는 인 축적능을 갖는 것으로 알려진 미생물인 Alcaligenes sp.의 생장 및 인 축적에 중금속이 미치는 영향을 정량적으로 평가하고자 실시되었다. 미생물의 생장 및 인 제거에 미치는 저해효과를 정량적 평가를 위해 생장저해 정도와 인 제거반응저해 정도를 IC₅₀와 EC₅₀를 이용하여 표현하였고, 중금속 간 교호작용의 평가를 위해 Additive Index Value method (A.I.V) 를 이용하여 중금속 간 혼합효과를 판단하였다. 실험 결과를 통해 Alcaligenes sp.의 생장 및 인 제거에 미치는 저해효과가 가장 큰 중금속은 카드뮴(Cd)이었다. 반면, 상대적으로 저해효과가 약한 중금속은 니켈(Ni)이었다. 모든 중금속은 처리 농도가 증가할수록 미생물의 생장과 인 제거율을 감소시키는 것을 확인할 수 있었다. 단일 중금속 처리시 IC₅₀에 해당하는 농도는 Cd 0.38, Cu 16.43, Zn 12.17, Pb 11.68, Ni 15.35 mg/L 이다. 연구에 사용된 균주 Alcaligenes sp. 의 인 제거율은 88.1%였고, EC₅₀에 해당하는 농도는 Cd 0.31, Cu 10.37, Zn 5.57, Pb 6.74, Ni 12.04 mg/L 이다. 두 종의 중금속을 혼합 처리하였을 때 IC₅₀에 해당하는 농도가 가장 낮은 중금속 처리구는 Cd + Cu 처리구였으며, 가장 높은 처리구는 Zn + Pb 처리구였다. EC₅₀의 농도는 Cd + Cu 처리구에서 가장 낮은 농도를, Cu + Ni 처리구에서 가장 높은 농도를 보였다. 중금속 간 교호작용은 대부분 길항효과(antagonistic effect)를 보였으나, IC₅₀의 경우, Cu + Zn, Cu + Pb, Cu + Ni, Pb + Ni 처리구에서 상승효과(synergistic effect)를 보이는 것을 확인할 수 있었고, EC₅₀에서는 Cu + Zn, Pb + Ni 처리구에서 상가효과(additive effect)를, Cu + Ni 처리구에서 상승효과(synergistic effect)를 보였다. 연구 결과는 중금속을 단일 및 2종 혼합 처리하였을 때 중금속이 인 제거 미생물의 생장 및 기능에 미치는 독성효과에 대한 기초자료를 제공함으로써 추후 진행될 미생물 단백질 동정, 중금속 독성평가에 관한 연구에 활용될 수 있을 것이라 사료된다.

• 대한예방한의학회지
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• 제4권1호
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• pp.51-69
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• 2000

This dissertation was to research how some metal level within SipJeonDaeBo - Decoction, one of oriental prescriptions, influence Sprague-Dawley animals. 1. Under the experiment with drinking waters there was no metal ${\sim}0.65\;mg/L$ detected. A metal with feed found 0.001-376.983mg/kg. 2. In the mice's kidney, brain, bones used experiment, As searched 0.474 mg/kg, 0.486 mg/kg, 0.314 mg/kg 0.834 mg/kg respectively ; Cd 0.060 mg/kg, 0.045 mg/kg, 0.030 mg/kg, 0.353 mg/kg, ; Co 0.105 mg/kg, 0.063 mg/kg, 0.030 mg/kg, 0.399 mg/kg, ; Cr 0.292 mg/kg, 0.304 mg/kg, 0.234 mg/kg, 0.962 mg/kg, ; Cu 4.201 mg/kg, 3.759 mg/kg, 1.923 mg/kg, 0.484 mg/kg, ; Fe 57.535 mg/kg, 150.571 mg/kg, 17.178 mg/kg, 281.506 mg/kg, ; no Hg, Mn 0.612 mg/kg, 2.968 mg/kg, 0.528 mg/kg, 4.205 mg/kg, ; Ni 0.094 mg/kg, 0.072 mg/kg, 0.078 mg/kg, 27.714 mg/kg, ; Pb 0.269 mg/kg, 0.293 mg/kg, 0.283 mg/kg, 43.142 mg/kg ; Zn 4.149 mg/kg, 21.861 mg/kg, 8.088 mg/kg, 226.283 mg/kg respectively. 3. In level of hazardous metal within idney control group searched 0.194 {\pm}\; 0.052 mg/kg, experimental I g개up $0.189{\pm}0.036\;mg/kg$, experimental I group $0.264 {\pm}{\pm}\;0.179\;mg/kg$. In level of non hazardous metal control group searched $15.917{\pm}5.575\;mg/kg$, experiment I group $17.064{\pm}2.246\;mg/kg$, experiment II group $16.892{\pm}3.586\;mg/kg$. Besides in total level of metal control g.cup detected $6.484{\pm}2.258\;mg/kg$, experiment I group $6.940{\pm}0.914\;mg/kg$, experiment II group $6.915{\pm} 1.508\;mg/kg$ There all was no statistical significance. 4. In level of hazardous metal within the liver control group searched $0.187{\pm}0.048\;mg/kg$, experiment I g개up $0.168[\pm}0.079\;mg/kg$, experiment II group $0.277{\pm}0.159\;mg/kg$. In level of non hazardous heavy metal control group detected $44.925{\pm}18.468\;mg/kg$, experiment I group $39.917{\pm}12.772\;mg/kg$, experiment II group $49.525{\pm}33.484\;mg/kg$. Besides in total concentration control group searched $18.082{\pm}7.395\;mg/kg$, experiment I group $16.068{\pm}5.128\;mg/kg$, experiment II group $19.977{\pm}13.443\;mg/kg$. There was no statistical significance but hazardous metal gets more level in the experilnent group than in the control group. 5. In level of hazardous metal within brain control group searched $0.145{\pm}0.056\;mg/kg$, experiment I group $$0.167{\pm}0.030\;mg/kg, erperiment II group $0.172{\pm}0.123\;mg/kg$. In level of non hazardous heavy metal control group detected $6.488{\pm}0.965\;mg/kg$, experiment I group $7.290{\pm}0.588\;mg/kg$, experiment II group $7.010{\pm}1.627\;mg/kg$. Besides in total concentration control group searched $2.683{\pm}7.395\;mg/kg$, experiment I group $3.017{\pm}0.238\;mg/kg$, experiment II group $2.908 {\pm} 0.711\;mg/kg$. Therefore there was no statistical significance. 6. In level of hazardous metal within bone control group searched $8.172{\pm}5.195 \;mg/kg$, experiment I group $9.128{\pm}4.143\;mg/kg$, experiment II group $9.401{\pm}6.924\;mg/kg$. There is statistical significance(p<0.05). In level of non hazardous metal control group detected $94.065{\pm}36.035\;mg/kg$, experiment I group $147.563 {\pm}79.939\;mg/kg$, experiment II group $142.730{\pm}77.374\;mg/kg$. Besides in total level control group searched $48.530{\pm}16.523\;mg/kg$, experiment I group $64.502{\pm}31.078\;mg/kg$, experiment II group $62.733 {\pm}34.641\;mg/kg$. Therefore there was no statistical significance. 7 In the correlative research as to how each metal influences to ingestion Cd and Co searched 0.954 and Pb and Ni -0.0884 from kidney. Co and Cd was 0.995 and Zn and As -0.190 from liver. Co and Cd were 0.995 and Zn and Cu -0.393 from brain. Co and Cd were 0.998 and Zn and Mn -0.206 from bones

• 자원환경지질
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• 제27권2호
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• pp.161-170
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• 1994

Jindong Granites are plotted mainly in the region of granodiorite~diorite of the Streckeisen's diagram, while Yucheon-Eonyang Granites and Onjonri Granites in the region of monzo-granite and monzo-granite~granodiorite, respectively. Jindong Granites show a differenciation trend of calc-alkaline magma, and its magmatic evolution from intermediate to acidic rocks, which might form mineralizing solution, is consistant with the general path of the Cretaceous granitic rocks including Yucheon-Eonyang Granites and Onjongri Granites. The differenciation index (D.I.) is 35~80 for Jindong Granites, which is lower than 85~95 of Yucheon-Eonyang Granites and is partly overlapped by 67~84 of Onjongri Granites. There is clear difference in content of some major and trace elements between Jindong Granites of Cu province and the other granitic rocks of Pb-Zn and Mo provinces. Between these metallogenic provicnes, Cu content is high in Jindong Granites near Haman-Gunbuk mineralized zone, while Pb and Zn are relatively abundant in Yucheon-Eonyang Granites and Mo in Onjongri Granites. Therefore, Jindong Granites of the Cu province are distinguishable by chemical compositions and their related geochemical characteristics from the other Cretaceous granitic rocks of Pb-Zn and Mo provinces. However, the content of Cu and Cl in biotite is applicable to distinguish a productive phase from a barren phase of Jindong Granites, because Cu and Cl show a trend to be concentrated in biotite of Jindong Gratites in the Haman-Gunbuk mineralized zone.

• BMB Reports
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• 제34권6호
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• pp.559-565
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• 2001

Protein carboxyl O-methyltransferase (E.C.2.1.1.24) may play a role in the repair of aged protein that is spontaneously incorporated with isoaspartyl residues. The porcine brain carboxyl O-methyltransferase was cloned in the pET32 vector, and overexpressed in E.coh (BL21) that harbors pETPCMT, which encodes 227 amino acids, including tagging proteins at the N-terminus. The protein sequence of the cloned porcine brain PCMT (r-pbPCMT) shares a 98% identity with that of human erythrocyte PCMT and rat brain PCMT. It is 100% identical with that of bovine brain. The r-pbPCMT was purified using Ni-NTA affinity chromatography and digested by enterokinase in order to remove the protein tags. Then Superdex 75HR gel filtration chromatography was performed. The r-pbPCMT exhibited similar in vitro substrate specificities with the PCMT that was purified from porcine brain. The molecular weight of the enzyme was estimated to be 24.5 kDa on the SDS polyacrylamide gel electrophoresis. The $K_m$ value was $1.1{\times}10^{-7}\;M$ for S-adenosyl-L-methionine. S-adnosyl-L-homocysteine was a competitive type of inhibitor with the $K_i$ value of $1.38{\times}10^{-4}\;M$. The enzyme has optimal activity at pH 6.0 and $37^{\circ}C$. These results indicate that the expressed enzyme is functionally similar to the natural protein. It also suggests that it may be a suitable model to further understand the function of the mammalian enzyme.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권3호
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• pp.93-108
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• 2013

This study is aimed to prepare the effective detail survey methods(Phase II) of abandoned metal mines through the contamination assessment for mine types and facilities in the abandoned metal mine areas. The study sites of 12 abandoned mines are located in Gyeonggi-do and Gangwon-do and those were chosen among 310 sites that the Phase II survey was conducted from 2007 to 2009 after considering the results of Phase I for abandoned mines scattered all over the country. 12 study sites were classified into four types; Type I sites only have pit mouth. Type II sites have pit mouth and mine-waste field. Type III sites have pit mouth and tailing sorting field. Type IV sites have pit mouth, tailing sorting field and concentrator(s). In forest land, paddy soil and farm land of Type I, As and Cd were showed average concentration, and Cu and Pb were high on the pit mouth area in one mines where the pit mouth was developed within 500 m. In the mines of Type II, Cu and Pb were showed average concentration too, but As and Cd were slightly high in pit mouth and mine-waste field. The mines of Type III which had grinding particle process through physical separation milling or hitting showed similar tendency with Type II. However, mines of Type IV pit mouth, mine-waste field and showed various results depending on defining the contamination sources. For example, if contamination source was pit mouth, the mixed results of Type I, II, II were showed. In tailing sorting field which was regarded as the most important source and having high mobility, however, if there were no facilities or it was difficult to access directly, field sampling was missed occasionally during phase I and phase II survey. For that reason, the assessment for tailing sorting field is missed and it leads to completely different results. In the areas of Type I mines, the concentration of heavy metals exceeded precautionary standards of soil contamination or not within 1,000 meters of pit mouth. Nickel(Ni) was the largest factor of the heavy metal contamination in this type. The heavy metals except Arsenic(As) were shown high levels of concentration in Type II areas, where pit mouth and mine-waste field were operated for making powder in upriver region; therefore, to the areas in the vicinity of midstream and downstream, the high content of heavy metals were shown. The tendency of high level of heavy metals and toxic materials contained in flotation agent used during sorting process were found in soil around sorting and tailing field. In the abandoned-pit-mouth area, drygrinding area and tailing sorting field area, the content of Cupper(Cu) and Zinc(Zn) were higher than other areas. Also, the contaminated area were larger than mine reclamation area(2,000 m) and the location of tailing sorting field was one of the important factors to estimate contaminated area.