• Economic and Environmental Geology
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• v.28 no.1
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• pp.9-17
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• 1995

The Kamkye Cu-Pb-Zn-Au-Ag deposits occur as quartz veins that filled fault-related fractures of NW system developed in the Cretaceous Gyeongsang basin. Three major stages of mineral deposition are recognized: (1) the stage I associated with wall rock alteration, such as sericite, chlorite, epidote and pyrite, (2) the early stage II of base-metal mineralization such as pyrite, hematite, and small amounts of sphalerite and chalcopyrite. and the middle to late stage II of Cu-As-Sb-Au-Ag-S mineralization, such as sphalerite, chalcopyrite, galena with tetrahedrite, tennantite, pearceite, Pb-Bi-Cu-S system, argentite and electrum. (3) the stage III of supergene mineralization, such as covellite, chalcocite and malachite. K-Ar dating of alteration sericite is a late Cretaceous ($74.0{\pm}1.6Ma$) and it may be associated with granitic activity of nearby biotite granite and quartz porphyry. Fluid inclusion data suggest a complex history of boiling, cooling and dilution of ore fluids. Stage II mineralization occurred at temperatures between 370 to $220^{\circ}C$ from fluids with salinities of 8.4 to 0.9 wt.% NaCl. Early stage II($320^{\circ}C$, 2.0 wt.% NaCl) may be boiled due to repeated fracturing which opened up the hydrothermal system to the land surface, and which resulted in a base-metal sulfide. Whilst the fractures were opened to the surface, mixing of middle-late stage II ore fluids with meteoric waters resulted in deposition of Cu-As-Sb-Au-Ag minerals from low temperature fluids(${\leq}290^{\circ}C$). Boiling of ore fluids may be occured at a pressure of 112 bar and a depth of 412 m. Equilibrium thermodynamic interpretation of sphalerite-tetraherite assemblages in middle stage II indicates that the ore-forming fluid had log fugacities of $S_2$ of -6.6~-9.4 atm.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.8
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• pp.720-725
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• 2007

Cold acoustic tests have been performed to elucidate the effect of baffle gaps on the optimal damping characteristics in a liquid rocket combustor where coaxial injectors are installed. For several axial baffle lengths, an optimal acoustic damping capacitance has been achieved in a certain gap range. Cold acoustic tests for simulating fluid viscosity by changing the pressure in a model chamber have been done to study the main mechanism of optimal damping. Experimental data have shown that the optimal gap for high damping capacity exists mainly due to the viscosity near the gap of baffles. Therefore, axial baffle length can be reduced by using the optimal baffle gap, providing a possible solution of thermal cooling problems. Also, these optimum characteristics can be some guidelines for manufacturing and assembling injectors in full-scaled rocket combustors.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.2
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• pp.108-116
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• 2014

With the increasing the importance of emotional quality of vehicle, the sound quality of systems with electric motor components has become increasingly important. Electric motors are used for windows, seats, sun roof, mirrors, steering columns, windshield wiper and climate control blowers, etc. In this paper, a study was conducted to identify sound quality factors that contribute to customer's satisfaction and preference of the window lift system. Jury test for subjective evaluation was carried out and sound quality index was developed. Averaged sound pressure level and sharpness were significant factors when glass moves down. Also, maximum loudness at stop section and averaged loudness were significant factor when glass moves up. Next, noise source identification was carried out using beam forming method during glass transferred section and impulsive noise at stop section. Several improvement methods were applied using the source identification result. And finally, the degree of sound quality improvement was judged using sound quality index.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1181-1181
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• 2001

Robinson with ${coworkers}^{1}$ have introduced two-state outer-neighbor bonding model to explain the anomalies of water. The studies on the properties of water as a function of temperature and pressure revealed that, unlike other ideas, all $H_2O$ molecules in liquid are tetrabonded. On the average they are forming two different bonding types. One type is the regular tetrahedral water-water bonding similar to that found in the ordinary ice Ih, whereas the other is a more dense nonregular tetrahedral bonding similar to that appearing in the ice II. The transformation between these two bonding forms is evidenced by FT-NIR experiment. The FT-NIR measurements were done for liquid water in the temperature range from $20^{\circ}C$ up to $80^{\circ}C$ in a wide extent of frequencies: 12 000 - 4000 $cm^{-1}$ /. Temperature dependent variations in the volume fraction of these two structures are directly related to the spectral changes. The absorbance variations are explored by means of the two-dimensional correlation spectroscopy (2DCOS), principal component analysis (PCA), curve fitting and second derivatives. The presence of the isosbestic points in a range of the combination and overtone transitions indicates that the experimental spectra are a superposition of two temperature independent components. One component of diminishing intensity with temperature increase, is assigned to a stronger hydrogen bonds occurred in the Ih type, whereas the second component showing an opposite behavior, one can attribute to a weaker H-bonds characteristic for the II type. The understanding of the hydrogen bonding network in the liquid water is very important in interpretation of the interaction between water and protein chain. The two-state model of water surrounding the protein surface could advance an understanding of the hydration process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.11
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• pp.717-721
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• 2017

We studied the performance enhancement of organic light-emitting diodes (OLEDs) using 2,3,5,6-fluoro-7,7,8,8-tetracyanoquinodimethane ($F_4-TCNQ$) as the hole-transport layer. To investigate how $F_4-TCNQ$ affects the device performance, we fabricated a reference device in an ITO (170 nm)/TPD(40 nm)/$Alq_3$(60 nm)/LiF(0.5 nm)/Al(100 nm) structure. Several types of test devices were manufactured by either doping the $F_4-TCNQ$ in the TPD layer or forming a separate $F_4-TCNQ$ layer between the ITO anode and TPD layer. N,N'-diphenyl-N,N'-di(m-tolyl)-benzidine (TPD), tri(8-hydroxyquinoline) aluminum ($Alq_3$), and $F_4-TCNQ$ layers were formed by thermal evaporation at a pressure of $10_{-6}$ torr. The deposition rate was $1.0-1.5{\AA}/s$ for TPD and $Alq_3$. The LiF was subsequently thermally evaporated at a deposition rate of $0.2{\AA}/s$. The performance of the OLEDs was considered with respect to the turn-on voltage, luminance, and current efficiency. It was found that the use of $F_4-TCNQ$ in OLEDs enhances the performance of the device. In particular, the use of a separate layer of $F_4-TCNQ$ realizes better device performance than other types of OLEDs.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.6
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• pp.541-548
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• 2015

We study the structural and functional characteristics of zinc oxide (ZnO) nanostructures that are grown on carbon nanotube (CNT) constructs via step-wise chemical vapor deposition (CVD). First, we optimize the CVD process to directly grow ZnO nanostructures on CNTs by controlling the growth temperature below $600^{\circ}C$, where CNTs can be sustained in a ZnO-growing oxidative atmosphere. We then investigate how the morphology and areal density of ZnO nanostructures evolve depending on process parameters, such as pressure, temperature, and gas feeding composition, while focusing on the effect of underlying CNT topology on ZnO nucleation and growth. Because various types of ZnO nanostructures, including nanowires, nanorods, nanoplates, and polycrystalline nanocrystals, can be conformally formed on highly conductive CNT platforms, this electrically addressable three-dimensional hybrid nanoarchitecture may better meet a wide range of nanoelectronic application-specific needs.

• Journal of Chest Surgery
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• v.25 no.3
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• pp.289-295
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• 1992

We evaluated the correlationship between the predicted defect size at preoperative examination and the actual defect size at operation room, by examining 69 cases of ventricular septal defect operated at the deparment of Thoracic and Cardiovascular surgery, Kyungpook University Hospital from January 1988 to December 1990. We excluded cases associated with other cardiac anomalies. Of the 69 cases, 39 are male and 30 female, forming 1.3:1 sex ratio in males favor. Their age range from 6 months to 16 year, and 4.3 on the average Their body weights are from 6 to 45kg and 15 on the average. According to Soto`s classification, perimembranous type costitutes 42 cases[61%], doubly committed subarterial type 23 cases[33%], and muscular type 4 cases[6%]. The average diameter of defect size is 8.0$\pm$3.5mm measured in 2D-echocardiogram, 5.6$\pm$3.4mm in angiogram, and 7.4$\pm$4.4mm in operative field. There is statistically significant correlation between the size from 2D-echocardiogram and actual defect size[p=0.001], and no significant difference between the two. Especially in the cases without anurysmal formation, they are nearly the same. Cardiothoracic ratio, pulmonary to systemic flow ratio, pressure ratio and resistance ratio also have statistically significant correlation. Main pumonary artery to descending aorta diameter ratio is correlated with the actual defect size. There is statistically significant correlation between the size from angiogram and actual defect size with some difference.

• Journal of the Korean Vacuum Society
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• v.7 no.3
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• pp.167-272
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• 1998

The fluorine doped silicon oxide (SiOF) intermetal dielectric (IMD) films havc been of interest due to their lower dielectric constant and compatibility with existing process tools. However, instability issues related to hond and increasing dielectric constant due to water absorption when the SiOF film was exposured to atmospheric ambient. Therefore, the purpose nf this research is to study the effect of post oxygen plasma treatment on the resistance of nioisture absorption and reliability of SiOF film. Improvement of moisture ahsorption resistance of SiOF film is due to the forming of thin $SiO_2$ layer at the SiOF film surface. It is thought that the main effect of the improvement of moisture absorption resistance was densification of the top layer and reduction in the numher of Si-F honds that tend to associate with OH honds. However, the dielectric constant was inucased when plasma treatment time is above 5 min. In this study, therefore, it is thought that the proper plasma treatment time is 3 min when plasma treatment condition is 700 W of microwave power, 3 mTorr of process pressure and $300^{\circ}C$ of substrate temperature.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.2
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• pp.213-222
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• 2001

Cylindrical type ceramic filers, that is 60 O.D$\times$10t$\times$600L and 60 O.D$\times$10t$\times$1,000L were manufactured by vacuum forming processes using ceramic ray materials. For cylindrical type ceramic filters, porosity and bulk density were measured for, 80 to 90% and 0.3 to 0.4 g/㎤, respectively at uniform pore size of 41 to 45${\mu}{\textrm}{m}$. Bench scale candle filters (60$\psi$ $\times$10t$\times$600L) were tested using different dusts collected from many industries including chemical processing, glass processing and metal manufacturing pants. Collection efficiencies found out to range from 99.87% to 99.90%, while resistance coefficients from 1.1$\times$10(sup)11/$m^2$ to 1.7$\times$10(sup)11/$m^2$ . Full scale low density ceramic filters (60$\psi$ $\times$10t$\times$1,000L) were also tested at 1 atm, $600^{\circ}C$ to reveal the filtration efficiency, conditioning, and resistance coefficients using two different types of dust as chemical processing and metal refined processing. Darcys law resistance coefficients were measured to range 1.44$\times$10(sup)11/$m^2$ to 2.74$\times$10(sup)11/$m^2$, and collection efficiencies on the range 99.84 to 99.96%, Finally, results of long term performance test showed that filters were conditioned after 170hrs. Experimental conditions for effective filtration were examined under the condition 10 cm/sec face velocity, 3kg/$\textrm{cm}^2$ pulsing pressure, 5 min filtration cycle, and 300msec pulse opening time.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2001.06a
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• pp.14-14
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• 2001

Nitride films such as TiN, CrN etc. deposited on glass by PVD processes have been developed for many industrial applications. These nitride films deposited on glass were widely used for not only decorative and optical coatings but also wear and corrosion resistance coatings employed as dies and molds made of glass for the example of lens forming molds. However, the major problem of nitride coatings on glass by PVD process is non-uniform film owing to pin-hole and micro crack. It is estimated that nonuniform coating is influenced by a different surface energy between metal nitrides and glass due to binding states. In this work, therefore, for the evaluation of nucleation and growth mechanism of nitride films on glass TiN and CrN film were synthesized on glass with various nitrogen partial pressure by unbalanced magnetron sputtering. Prior to deposition, for the examination of relationship between surface energy and film microstructure plasma pre-treatment process was carried out with various argon to hydrogen flow rate and substrate bias voltage, duty cycle and frequency by using pulsed DC power supply. Surface energy owing to the different plasma pre-treatment was calculated by the measurement of wetting angle and surface conditions of glass were investigated by X-ray Photoelectron Spectroscopy(XPS) and Atomic Force Microscope(AFM). The microstructure change of nitride films on glass with increase of film thickness were analyzed by X-Ray Diffraction(XRD) and Scanning Electron Microscopy(SEM).