• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.24-24
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• 1998

반도체장비를 포함하는 초고진공장비의 園훌化가 급속히 그리고 절실히 요구되고 있는 것이 현실정이다. 當面해서 실현할 국산진공장비의 대상은 廣範圍하다. 즉, 각종 진공 pump ( (rotary, dry, diffusion, cryo, ion, turbo melecular pump), 진공 chamber, 진공 line, gate valve 를 위 시 한 진공 V머ve, flange, gasket, fl않d야lU, mainpulater 퉁 진공 部品이 다. 진공계 의 핵심 은 適切하고 優良한 진공재료의 선태파 사용이다. 진공장비는 사용자가 원하는 진공도를 원하 는 시간 동안 륨空度를 유지해 주어야 한다. 진공재료 선태의 기준사항은:(1) 기체의 透過성 (2) 薰했훌 (3) 혔體放出특성 - -outgassing과 degassing- (4) 機械的 량훌度 (5) 온도 의존성 (6) 化學톡성 (7) 加I성 및 鎔接 성 (8) 課電특성 (9) 磁氣특성 (10) 高速함子 및 放射線 특성 (11) 經濟성 및 調達생 둥이 다. 우량한 초고진공계재료는 풍부하게 개발되어 왔고, 또 新材料들이 개발되고 있다. 여기에서는 주로 초고진공 내지는 극고진공계의 構造材料, 機能材料, 部品材料 일반파 몇가지 신재료의 특 성에 관해서 記述한다. M Mild SteeHSAE, 1112, 1010, 1020, 1022, etc)., S Stainless SteeHAlSI, 304, 304L, 310, 316, 321, 347): 구조재료, chamber, fl하1ges A Aluminum과 Alloys (1060, 1100, 2014, 4032, 6(뻐1): 구조재료, chamber, flanges, gaskets A AI, Al 떠loy는 SS에 代替하는 역 할올 시 작하고 있다. C Copper, Copper Alloys(C11$\alpha$)0, C26800, C61400, Cl7200): 내장인자, gasket, cryopanel, tubing T Titanium, Ziriconium, Haf띠um 및 Alloys: 특히 Ti은 10n pump 용 getter material 이 외 에 U UHV,XHV용 chamber계로서 관심올 끌고 있다. N Nickel, Nickel Alloys (200, 204, 211, monel, nichrome): 부식 방지 , 전자장치 , 자기 장치 귀 금속(Ag, Au, Pt, Pd, Rh, Ir, Os, Ru): 보조부품, gasket, filament, coating, thermocouple, 접 합부위 T TiC, SiC, zrC, HfC, TaC 둥의 탄화물과, BN, TiN, AlN 동의 질화물, 붕화물이 둥장하고 었 다. 유리: Soda Lime, Borosilicate, Potash Soda Lead: View Port, Chamber envelope C Ceramics: AlZ03, BeO, MgO, zrOz, SiOz, MgOzSiOz, 3Alz032SiOz, Z$textsc{k}$hSiOz S상N4: e electrical, thermal insulators, crucibles, boats, single crystals, sepctr려 windows 저자는 최근 저자들이 발견한 Zr-Ti-Cu-Ni-Be amorphous alloys coated cham뾰r가 radiation p proof로 이용될 수 있는 사실을 점검하고 었다 .. Z.Y. Hua 들은 Cs3Sb를 새로운 photocathode 재료로 보고하고 있다.

• Journal of the Mineralogical Society of Korea
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• v.17 no.4
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• pp.309-325
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• 2004

The Cannington Ag-Pb-Zn deposit, northwest Queensland, Australia developed around the host rocks composing banded and migmatitic gneisses, sillimanite-garnet schist and amphibolite. Three crystal habits of sillimanite, gahnite (Zn-spinel) and garnet porphyroblasts occurred on the host rocks of the Cannington deposit could be used to delineate metamorphism that closely associated with Zn-mineralization in the deposit. Linkages the metamorphism to Zinc-mineralization is determined in four chemical systems, KFMASH (K$_2$O-FeO-MgO-Al$_2$O$_3$-SiO$_2$-$H_2O$), KFMASHTO (K$_2$O-FeO-MgO-Al$_2$O$_3$-SiO$_2$-$H_2O$-TiO$_2$-Fe$_2$O$_3$), NCKFMASH (Na$_2$O-CaO-K$_2$O-FeO-MgO-AlO$_3$-SiO$_2$-$H_2O$) and MnNCK-FMASH (MnO-Na$_2$O-CaO-K$_2$O-FeO-MgO-AlO$_3$-SiO$_2$-$H_2O$), using THERMOCALC program (version 3.1; Powell and Holland 1988). Partial melting in MnNCKFMASH and NCKFMASH systems occurs at lower temperature than in the KFMASH and KFMASHTO systems. The partial melting temperature decreases with increasing of Na/(Na+Ca+K) of the bulk rock compositions in the MnNCKFMASH system. The host rocks have melted ca 15 vol.% in the MnNCKFMASH system at peak metamorphic conditions (634$\pm$62$^{\circ}C$ and 4.8$\pm$1.3 kbar), but partial melting have not occurred in KFMASHTO system. Based on calculations of sillimanite isograd in different systems and sillimanite modal pro-portion, prismatic and rhombic sillimanite and gahnite porphyroblasts including prismatic sillimanite inclusion probably have resulted from pressure and temperature increasing through partial melting (from 550～$600^{\circ}C$, 2.0～3.0 kbar to 700～75$0^{\circ}C$, 5.0～7.0 kbar), furthermore have experienced N-S then W-E crustal shortening during D$_1$ and D$_2$ deformation. Consequently, Zinc mineralization related to gahnite growth occurred during D$_2$ and was redistributed and upgraded by partial melting and retrograde metamorphism into structural and rheological sites during shearing in D$_3$.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.1
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• pp.56-72
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• 1999

Airborne concentrations of welding fumes in which 13 different metals such as Al, Cd, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Si, Sn, Ti, and Zn were analyzed were measured at 18 factories including automobile assembly and manufactures, steel heavy industries and shipyards. Air samples were collected by personal sampler at each worker's worksite(n=339). Blood levels of Cd, Cu, Fe, Mn, Pb and Zn were also measured from samples taken from 447 welders by atomic absorption spectrometry and compared with control values obtained from 127 non-exposed workers. The results were as follows ; 1. Among various welding types, $CO_2$ welding 70.2 % were widely used, shielded metal arc welding(SMAW) 22.1 % came next, and rest of them were metal inert gas(MIG) welding, submerged arc welding(SAW), spot welding(SPOT) and tungsten inert gas(TIG) welding. 2. Welding fume concentration was $0.92mg/m^3$($0.02{\sim}15.33mg/m^3$) at automobile assembly and manufactures, $4.10mg/m^3$($0.02{\sim}70.75mg/m^3$) at steel heavy industries and $5.59mg/m^3$($0.30{\sim}91.16mg/m^3$) at shipyards, respectively, showing significant difference among industry types. Workers exposed to high concentration of welding fumes above Korean Permissible Exposure Limit(KPEL) amounted to 7.9 % and 12.5 %, in $CO_2$ welding and in SMAW at automobile assembly and manufactures and 62.7 % in $CO_2$ welding, and 12.5 % in SMAW at shipyards, and 66.2 % in $CO_2$ welding and 70.6 % in SMAW at steel heavy industries. 3. Geometric mean of airborne concentration of each metal released from welding fumes was below one 10th of KPEL in all welding types. Percentage of workers, however, exposed to airborne concentration of metals above KPEL amounted to 16.8 % in Mn and 7.6 % in Fe in $CO_2$ welding; 37.5 % in Cu in SAW, 30 % in Cu in TIG; and 25 % in Pb in SPOT welding. As a whole, 76 Workers(22.4%) were exposed to high concentration of any of the metals above KPEL. 4. There were differences in airborne concentration of metals such as Al, Cd, Cr, Cu. Fe. Mn, Mo, Ni, Pb, Si, Sn, Ti and Zn by industry types. These concentrations were higher in shipyards and steel heavy industries than in automobile assembly and manufactures. Workers exposed to higher concentration of Pb above KPEI amounted to 7.4 % of workers(7/94) in automobile assembly and manufactures. In shipyards, 19.2 % of workers(19/99) were over-exposed to Mn and 7.1 % (7/99) to Fe above KPEL. In steel heavy industries, 14.4 %(21/146), 7.5 %(11/146) and 13 %(19/146) were over-exposed to Mn, Fe and Cu, respectively. As a whole, 76 out of 339 workers(22.4%) were exposed to any of the metals above KPEL. 5. Blood levels of Cd, Cu, Fe, Mn, Pb, and Zn in welders were $0.11{\mu}g/100m{\ell}$, $0.84{\mu}g/m{\ell}$, $424.4{\mu}g/m{\ell}$, $1.26{\mu}g/100m{\ell}$, $5.01{\mu}g/100m{\ell}$ and $5.68{\mu}g/m{\ell}$, respectively, in contrast to $0.09{\mu}g/100m{\ell}$, $0.70{\mu}g/m{\ell}$, $477.2{\mu}g/m{\ell}$, $0.73{\mu}g/100m{\ell}$, $3.14{\mu}g/100m{\ell}$ and $6.15{\mu}g/m{\ell}$ in non-exposed control groups, showing significantly higher values in welders but Fe and Zn.

• Economic and Environmental Geology
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• v.31 no.4
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• pp.297-310
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• 1998

Geochemical characteristics of environmental toxic elements at the Narim mine area were investigated on the basis of major, minor, rare earth element geochemistry and mineralogy. Ratios of $Al_2O_3/Na_2O$ and $K_2O/Na_2O$ in soils and sediments range from 11.57 to 22.21 and from 1.86 to 3.93, and are partly negative and positive correlation against $SiO_2/Al_2O_3$ (3.41 to 4.78), respectively. These suggested that sediment source of host granitic gneiss could be due to rocks of high grade metamorphism originated by sedimentary rocks. Characteristics of some trace and rare earth elements of V/Ni (0.33 to 1.95), Ni/Co (2.00 to 6.50), Zr/Hf (11.27 to 53.10), La/Ce (0.44 to 0.55), Th/Yb (4.07 to 7.14), La/Th (2.35 to 3.93), $La_N/Yb_N$ (6.58 to 13.67), Co/Th (0.63 to 2.68), La/Sc (3.29 to 5.94) and Sc/Th (0.49 to 1.00) are revealed a narrow range and homogeneous compositions may be explained by simple source lithology. Major elements in all samples are enriched $Al_2O_3$, MgO, $TiO_2$ and LOI, especially $Fe_2O_3$ (mean=7.36 wt.%) in sediments than the composition of host granitic gneiss. The average enrichment indices of major and rare earth elements from the mining drainage are 2.05 and 2.91 of the sediments and are 2.02 and 2.60 of the soils, normalizing by composition of host granitic gneiss, respectively. Average composition (ppm) of minor and/or environmental toxic elements in sediments and soils are Ag=14 and 1, As=199 and 14, Cd=22 and 1, Cu=215 and 42, Pb=1770 and 65, Sb=18 and 3, Zn=3333 and 170, respectively, and extremely high concentrations are found in the subsurface sediments near the ore dump. Environmental toxic elements were strongly enriched in all samples, especially As, Cd, Cu, Pb, Sb and Zn. The level of enrichment was very severe in mining drainage sediments, while it was not so great in the soils. Based on the EPA value, enrichment index of toxic elements is 8.63 of mining drainage sediments and 0.54 of soils on the mining drainage. Mineral composition of soils and sediments near the mining area were partly variable being composed of quartz, mica, feldspar, amphibole, chlorite and clay minerals. From the gravity separated mineralogy, soils and sediments are composed of some pyrite, arsenopyrite, chalcopyrite, sphalerite, galena, goethite and various hydroxide minerals.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.05a
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• pp.155-160
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• 2002

Metal matrix composites had generated a lot of interest in recent times because of significant in specific properties. It was also highlighted as the materials of frontier industry because strength, heat-resistant, corrosion-resistant, wear-resistant were superiored. In this study the strength properties of $Al_{18}B_4O_{33}/AC4CH$ were represented mixing the binder of $Al_2O_3$ and $TiO_2$. It was also fabricated by squeeze casting. $Al_{18}B_4O_{33}/AC4CH$ was fabricated at the melt temperature of $760^{\circ}C$ the perform temperature of $700^{\circ}C$ and mold temperature of $200^{\circ}C$ under the pressure of 83.4MPa and observed SEM. Fatigue crack growth rate tests on compact tension specimen(half-size) of thickness 12.5mm were conducted by using sinusoidal waveform. Compact tension specimens(half-size) were used and fatigue crack growth rate da/dN and stress intensity factor range ${\Delta}K$ were analyzed concerning to the R value of 0.1 and 0.05. In order to find out the value of ${\Delta}K$, load amplitude constant method was applied by the standard fatigue testing method describes in ASTM E647-95a. As the results of this study, Fatigue crack growth rate increased with in creasing the load ratio, Consequently, At equivalent stress intensity factors, the fatigue crack growth rates in MMC were faster than those of AC4CH alloy. then the fatigue life and the fatigue crack growth rate was investigated using scanning election microscopy(SEM)

• Journal of the Speleological Society of Korea
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• v.34 no.35
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• pp.32-42
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• 1993

The Paektu-san mountains are geographically situated in the Korea strait to the north of the main peninsula, coordinated between the longitudes of W(127$^{\circ}$15'~128$^{\circ}$00')and E(128$^{\circ}$15'~129$^{\circ}$00'), and between the latitudes of S(41$^{\circ}$15'~42$^{\circ}$00') and N(42$^{\circ}$10'~42$^{\circ}$40'). The volcanic group of the Paektu-san mountains can be devided into 2 main kinds of volcanos by the method investigation, The ashes are mainly made of tremolite, trachte, basalt and pumice, or, a little quartz, labradorite and volcanic glass. These sorts, ratios and forms of the rocks are respectively similar. The Haeven lake is surrounded by 19 peaks. The central volcanic cone is a secant cone in shape, with an altitude of the 1800m to 2749,2m (Chang-kun-bong), an average diameter of 10km, and a shape of an ellipse seen high from the plane. They say there were several eruptions in 1668, 1700 and 1702 A. D. The crystal structure of the rock sample collected at the cave of Mt. Paektu-san is monoclinic. The quantitative analysis of the rock samples in the cave is done by using XRF this time. The chemical compositions by XRF fundamamental parameter analysis is : SiO$_2$: 50.72Wt%, TiO = 2.422Wt%, $Al_2$O$_3$= 17.65Wt%, Fe$_2$O$_3$= 9.371Wt%, CaO = 8.711Wt%, MgO = 4.l19Wt%, MnO = 0.l15Wt%, $K_2$O = 1.369Wt%, Na$_2$O : 3.028Wt% and P$_2$O$_{5}$ = 0.365Wt%. The K-Ar age of the rock sample is also determined to be 0.16Ma. This paper describes some problems experienced in dating young volcanic rocks, and then discusses chemical compositions, X-ray fluorescence analyses and the age of the formation of a lava tunnel such as in Mt. Paektu-san.n.

• 한국지구과학회:학술대회논문집
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• 2005.09a
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• pp.136-141
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• 2005

The K Ar ages, whole rock geochemistry and Sr Nd Pb isotopes have been determined for the submarine basalts dredged from the P2 and P3 segments of the Antarctic-Phoenix Ridge (APR), Drake Passage, Antarctica, for better understanding on temporal variation of magma chemistry in association with extinction of seafloor spreading. The fossilized APR is distant from the known hot spots, and consists of older N-MORB prior to extinction of spreading and younger E-MORB after extinction. The older N-MORB (3.5-6.4 Ma) occur in the southeast flank of the P3 segment (PR3) and the younger E-MORB (1.4-3.1 Ma) comprise a huge seamount at the P3 segment (SPR) and a big volcanic edifice at the P2 segment (PR2). The N-type PR3 basalts have higher Mg#, K/Ba, and CaO/Al2O3 and lower Zr/Y, Sr, and Na8.0 with slight enrichment in incompatible elements and almost flat REE patterns. The E-type SPR and PR2 basalts are highly enriched in incompatible elements and LREE. The extinction of spreading occurring at 3.3 Ma seems to have led to a temporal magma oversupply with E-MORB signatures. Geochemical signatures such as Ba/TiO2, Ba/La, and Sm/La suggest heterogeneity of upper mantle and formation of E-MORB by higher contribution of enriched materials to mantle melting, compared to N-MORB environment. E-MORB magmas beneath the APR seem to have been produced by low melting degree (up to 1% or more) at deeper low-temperature regime, where metasomatized veins consisting of pyroxenites have preferentially participated in the melting. The occurrence of E-MORB at the APR is a good example to better understand what kinds of magmatism would occur in association with extinction of spreading.

• Bulletin of the Korean Chemical Society
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• v.25 no.5
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• pp.687-693
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• 2004

Composite membranes with a titania layer were prepared by soaking-rolling method with the titania sol of nanoparticles formed in the sol-gel process and investigated regarding the vapor permeation of various organic mixtures. The support modification was conducted by pressing $SiO_2$ xerogel of 500 nm in particle size under 10 MPa on the surface of a porous stainless steel (SUS) substrate and designed the multi-layered structure by coating the intermediate layer of ${\gamma}-Al_2O_3$. Microstructure of titania membrane was affected by heat-treatment and synthesis conditions of precursor sol, and titania formed at calcination temperature of 300$^{\circ}C$ with sol of [$H^+$]/[TIP]=0.3 possessed surface area of 210 $m^2$/g, average pore size of 1.25 nm. The titania composite membrane showed high $H_2/N_2$ selectivity and water/ethanol selectivity as 25-30 and 50-100, respectively. As a result of vapor permeation for water-alcohol and alcohol-alcohol mixture, titania composite membrane showed water-permselective and molecular-sieve permeation behavior. However, water/methanol selectivity of the membrane was very low because of chemical affinity of permeants for the membrane by similar physicochemical properties of water and methanol.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.117-117
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• 2016

Total ankle replacement (TAR) is a visible option in the surgical treatment of degenerative or inflammatory diseases of ankle joint. it is attributed to the current TAR which has improvements in surgical technique, uncemented implant fixation and minimally constrained articulation. In the clinical result, they can show promised surgical result when compared to earlier attempts in TAR. However, TAR is still not as successful as total knee replacement (TKR) or total hip replacement (THR), it needs to be note that there are limitations in concerning of long term performance of TAR, the high failure rate still associated with wear of the PE (polyethylene) component that has related with their material property and surface roughness. The aim of this study was to introduce the tribology characteristics of total ankle joint prosthesis with one of TDR model which was fabricated to try multi-axis wear test as a region of motion in ankle joint. The wear specimen of TDR was prepared with Ti-6Al-4V alloy and UHMWPE (ultra-high molecular weight polyethylene) for tibia-talus and bearing component, respectively. A wear test was carried out using a Force 5 (AMTI, Massachusetts, US) wear simulator which can be allowed to move in three axis to flexion-extension ($+3^{\circ}{\sim}-6^{\circ}$), internal-external axial rotation (${\pm}5^{\circ}$), as well as sinusoidal compressive load (1.6 kN, R=10). All tests were performed following standard ISO 14243, wear rate was calculated with weight loss of UHMWPE bearing while the specimen has tested at certain cycles. As based on the preliminary results, wear rate of UHMWPE bearing was $7.9{\times}10^{-6}mg/cycles$ ($R^2=0.86$), calculated loss weight until $10^7cycles$ was 79 mg, respectively.

• Transactions of the Korean hydrogen and new energy society
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• v.16 no.3
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• pp.244-252
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• 2005

It is very interesting and important in the academic point of view and in practical use the hydrogen-induced phase separation(HIPS) which appears during hydrogen heat treatment. Since hydrogen can be removed very fast by pumping it out the hydrogen-induced new lattice phase which can not be obtained without hydrogen can be preserved as meta-stable state. In this study it has been investigated whether the HIPS appear in Pd-Al, Pd-Co, Pd-Cr, Pd-Ti, Pd-V and Pd-Zr alloys and discussed thermodynamic representation of the HIPS. The Pd alloys were arc-melted under argon atmosphere and remelted 4 or 5 times for homogenization. The alloys were annealed at 600$^{\circ}C$ under vacuum for 24 hrs and then subjected to pressure-composition isotherm measurements at 100$^{\circ}C$. The hydrogen heat treatment(HHT) of samples was carried out at 600$^{\circ}C$ under hydrogen pressure of 70 bar for 6 days and PC isotherms at 100$^{\circ}C$ were measured. By comparing the PC isotherms measured before and after HHT, occurrence of phase separation was determined. The experimental results showed that the HIPS appeared only in Pd-0.05Co alloy. For Pd-Co alloys with various composition the PC isotherms were measured. By adopting Park-Flanagan model for ternary thermodynamics the Gibbs free energy change for Pd-Co-H solid solution was calculated and subsequently with this the HIPS in Pd-Co alloy was explained fairly.