• Journal of Korea Water Resources Association
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• v.38 no.4 s.153
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• pp.281-292
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• 2005

The water balance analysis for the long-term water resources plan is a simple calculation that compares water demands with possible water supplies. For a watershed being considered the reports on the performance of the water balance analysis, however, have shown inconsistent results and thus have not earned credibility due to the uncertainty of the data acquired and models used. In this research, uncertainties in the water scarcity estimate were assessed through probability representation based on the Monte Carlo simulation using Latin Hypercube Sampling (LHS). The natural flow, municipal demand, industrial demand, agricultural demand, and return flow rate were selected as representative input variables for the water balance analysis, and their distributions were set based on the linear regression and the entropy theory. The statistical properties of the output variable samples were analyzed in comparison with a deterministic estimate of the water scarcity of an existing study. Application of LHS to three sub-basins of the Geum river basin showed the deterministic estimate could be overestimated or underestimated. The sensitivity analysis as well as the uncertainty analysis found that the return flow rate of the agricultural water is the most uncertain but is rarely sensitive to the output of the water balance analysis.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.176-177
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• 2013

Surface plasmon polaritons (SPPs) have attracted the attention of scientists and engineers involved in a wide area of research, microscopy, diagnostics and sensing. SPPs are waves that propagate along the surface of a conductor, usually metals. These are essentially light waves that are trapped on the surface because of their interaction with the free electrons of conductor. In this interaction, the free electrons respond collectively by oscillating in resonance with the light wave. The resonant interaction between the surface charge oscillation and the electromagnetic field of the light constitutes the SPPs and gives rise to its unique properties. In this papers, we studied theoretical and experimental extraordinary transmittance (T) and reflectance (R) of 2 dimensional metal hole array (2D-MHA) on GaAs in consideration of the diffraction orders. The 2d-MHAs was fabricated using ultra-violet photolithography, electron-beam evaporation and standard lift-off process with pitches ranging from 1.8 to $3.2{\mu}m$ and diameter of half of pitch, and was deposited 5-nm thick layer of titanium (Ti) as an adhesion layer and 50-nm thick layer of gold (Au) on the semiinsulating GaAs substrate. We employed both the commercial software (CST Microwave Studio: Computer Simulation Technology GmbH, Darmstadt, Germany) based on a finite integration technique (FIT) and a rigorous coupled wave analysis (RCWA) to calculate transmittance and reflectance. The transmittance was measured at a normal incident, and the reflectance was measured at variable incident angle of range between $30^{\circ}{\sim}80^{\circ}$ with a Nicolet Fourier transmission infrared (FTIR) spectrometer with a KBr beam splitter and a MCT detector. For MHAs of pitch (P), the peaks ${\lambda}$ max in the normal incidence transmittance spectra can be indentified approximately from SP dispersion relation, that is frequency-dependent SP wave vector (ksp). Shown in Fig. 1 is the transmission of P=2.2 um sample at normal incidence. We attribute the observation to be a result of FTIR system may be able to collect the transmitted light with higher diffraction order than 0th order. This is confirmed by calculations: for the MHAs, diffraction efficiency in (0, 0) diffracted orders is lower than in the (${\pm}x$, ${\pm}y$) diffracted orders. To further investigate the result, we calculated the angular dependent transmission of P=2.2 um sample (Fig. 2). The incident angle varies from 30o to 70o with a 10o increment. We also found the splitting character on reflectance measurement. The splitting effect is considered a results of SPPs assisted diffraction process by oblique incidence.

• Journal of Biosystems Engineering
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• v.6 no.2
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• pp.1-8
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• 1982

The objective of this study was to find out the technical feasibility of ethanol-diesel fuel blends as a diesel engine fuel. Fuel properties essential to the proper operation of a diesel engine were determined for blends containing several concentrations of ethanol in No. 2 diesel fuel. A single-cylinder diesel engine for a power tiller was used for the engine tests, in which load, speed and fuel consumption rate were measured. The fuels used in tests were No. 2 diesel fuel and a blend containing 10-percent ethanol and 90-percent No. 2 diesel fuel. The results of the study are summarized as follows. 1. It was not possible to blend ethanol and No. 2 diesel fuel as a homogeneous solution even though anhydrous ethanol was used. The problem of blending ethanol in No. 2 diesel fuel could be solved by adding butanol about 5% of the amount of ethanol in the blends. 2. Because ethanol had a much lower boiling point ($78.3^{\circ}C$ under atmospheric pressure) than a diesel fuel, it was necessary to store ethanol-diesel fuel blends airtight in order to prevent them from evaporation losses of ethanol. 3. The addition of ethanol to No. 2 diesel fuel lowered the fuel viscosity and the cetane rating, but a blend of 10% ethanol and 90% diesel fuel had a viscosity and a cetane rating well above the KS minimum values for No. 2 diesel fuel. 4. At the rated speed, the specific fuel consumption of No.2 diesel fuel was lower than that of the 10% ethanol blend for the almost entire range of load. However, under the overload condition the specific fuel consumption was lower for the 10% ethanol blend. 5. Under the variable-speed full-load tests, both fuels produced approximately the same torque and power. At the speeds of 1600rpm or below, the specific fuel consumption of No. 2 diesel fuel was lower than that of the 10% ethanol blend. At the speeds of 1600rpm or above, however, the specific fuel consumption was lower for the 10% ethanol blend. 6. At the ambient temperature above $15^{\circ}C$, the use of the 10% ethanol blend in the engine created a vapor lock in the fuel injection pump and stalled the engine. The vapor locking problem was overcome by chilling the surroundings of the fuel injection pump and the cylinder head with water.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.535-541
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• 2020

FCAW is used mainly in the welding of carbon steel and alloy steel because it can be welded in all positions and can obtain excellent quality at sites with variable working conditions. Recently, many studies in Korea have estimated the fatigue strength, residual stress, and deformation, and to develop a fillet welding process. On the other hand, there have been few studies of the mechanical properties based on the strength, macro and magnetic particle test results for fillet welding. This study shows the following results through fillet welding, macro testing and strength testing using SM490A (solid-structure rolled steel) for thick plates using SS400 (rolled steel) for the upper plate and FCAW. The hardness test, macro test and magnetic particle test were then conducted. The hardness tests showed that all result values were smaller than the KS B 0893 standard values of 350Hv. The macro-test showed that each type of welded part was in a normal organic state and that there were no internal errors, bubbles, or impurities on the front of the welded part. Therefore, there were no concerns about lamination. The magnetic particle examination showed no problems.

• Journal of Conservation Science
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• v.23
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• pp.81-93
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• 2008

The analysis of ancient DNA (aDNA) in paleogenetics has become an increasingly important subject of archaeological, anthropological, biological as well as public interest. In this study, paleogenetic analyses were carried out on the human skeletal remains from a historical cemetery site in Myeongam-ri, Asan, Korea. Archaeological records show that this particular location had been used as a habitation or mortuary site as early as the Bronze Age and up until the Joseon Dynasty. Human remains of twenty individuals out of forty-nine tombs from the Goryeo to Joseon Dynasty were selected for the analysis of this study. In order to identify the genealogy of the population and traditional burial pattern of the cemetery, we conducted comparative analyses of the hyper variable regions (HVRs) in mitochondrial DNA (mtDNA) of each sample. A number of cautious steps were taken at all experimental stages in order to avoid erroneous recombination by the segmental and modern contaminations derived from the researchers. We sequenced segmental amplicons of HVRs andassigned relevant haplogroups according to the sequence polymorphism on the basis of the known mtDNA database. The result shows that diverse haplogroups were unexpectedly present in the small population group of the Myeongam-ri site. This diversity appears to be related to the geographical conditions and archaeological properties of the Myeongam-ri site.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.8
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• pp.1209-1223
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• 2009

In this review, the terminology that is used to describe ileal amino acid (AA) digestibilities in piglet feed ingredients is defined. If one accepts that the determination of AA digestibilities should be based on the ileal analysis method, one should consider that ileal digesta contains variable amounts of endogenous crude protein (CP), which originates mainly from digestive secretions, sloughedoff epithelial cells and mucins. The ileal endogenous CP and AA losses are separated into basal ileal endogenous CP and AA losses ($IAAL_{B}$), which are not influenced by the feed ingredient composition, and specific ileal endogenous CP and AA losses ($IAAL_{S}$), which are induced by feed ingredient characteristics such as level and type of fiber and anti-nutritional factors (ANF). Depending how ileal endogenous CP and AA losses are considered in the measurement of CP and AA digestibilities, digestibility values are expressed as apparent (AID), standardized (SID), or true (TID) ileal digestibilities of CP and AA. The main concern associated with the use of AID values in diet formulation for pigs is that they are not additive in mixtures of feed ingredients. Consequently, the concept of standardized ileal CP and AA digestibilities was introduced by correcting AID values for basal ileal endogenous CP and AA losses ($IAAL_{B}$). The correction for both $IAAL_{B}$ and $IAAL_{S}$ yields TID values, however, routine procedures to measure $IAAL_{S}$ are not yet available. In principle, SID values should be preferred, because they represent the fundamental properties of the feed ingredient. There exist only few reports on SID of CP and AA in feedstuffs frequently used in piglet nutrition. These include soybeans (SB), soybean meal (SBM), soy proteins (SP), soy protein concentrate (SPC), soy protein isolate (SPI), corn gluten (CG), wheat gluten (WG), pea protein (PeaP), potato protein (PotP), fish meal (FM) and whey proteins (WP), but the results obtained are inconsistent. Differences in SID values within feed ingredients may, at least in part, be attributed to different processing conditions or inherent differences of the assay feed ingredients. Moreover, there is some evidence that the determination of SID values and $IAAL_{B}$ in piglets may be confounded by the dietary CP level of the assay diet, age and (or) body weight (BW), the level of feed intake or the methodological approach used to determine $IAAL_{B}$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.755-760
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• 2016

The demand for independent generators using renewable energy has been increasing. Among those independent generators, small wind turbine generators have been actively developed. Permanent magnets are generally used for small wind turbine generators to realize a simple structure and small volume. On the other hand, cogging torque is included due to the structure of the permanent magnet synchronous machine, which can be the source of noise and vibration. The cogging torque can be varied by the shape of the permanent magnet and core, and it can be reduced using the appropriate design techniques. This paper proposes a design technique that can reduce the cogging torque by changing the shape of the permanent magnets for SPMSM (Surface Permanent Magnet Synchronous Motor), which is used widely for small wind turbine generators. Evolution Strategy, which is one of non-deterministic optimization techniques, was adopted to find the optimal shape of the permanent magnets that can reduce the cogging torque. The angle and outer diameter of permanent magnet were set as the design variable. A 300W class wind turbine generator, whose pole/slot combination was 8 poles/18 slots, was designed with the proposed design technique. The properties of the generator, including the cogging torque and output voltage, were calculated. The calculation results showed that the cogging torque of the optimized model was reduced compared to that of the initial model. The design technique proposed by this paper can be an effective measure to reduce the cogging torque.

• Journal of the Korean Society for Advanced Composite Structures
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• v.2 no.4
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• pp.19-27
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• 2011

In this paper, we present a part of results to develop new type hybrid FRP-concrete composite pile (i.e., concrete filled fiber reinforced plastic circular tubes, hybrid CFFT, HCFFT). The purpose of this paper is to evaluate compressive loading capacity through compressive strength test. Before compressive strength test of HCFFT, we investigated mechanical properties of pultruded fiber reinforced plastic (PFRP) and filament winding fiber reinforced plastic (FFRP). For estimating the compressive strength of HCFFT, uni-axial compression strength tests of HCFFT compression members were conducted. The test variables are compressive strengths of concrete and thickness of FFRP. In addition, uni-axial compression strength tests of concrete filled fiber reinforced plastic circular tube (CFFT) except PFRP members were conducted. The test variable in the test is thickness of FFRP. From the test result, the compressive strength of the HCFFT in larger than compressive strength of CFFT as much as 47%. It can be observed that the uni-axial compressive strength of the HCFFT increased if the concrete strength and the thickness of exterior filament winding FRP tube increased. In addition, the finite element analysis result is compared with the experimental result. The difference between the experimental and FEM results is in the range of 0.14% to 17.95%.

• Tunnel and Underground Space
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• v.12 no.3
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• pp.142-151
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• 2002

Claesson(2001)'s analytical solution, and two numerical models with Dirichlet and Neuman interior boundary condition respectively were investigated to estimate the transient temperature distribution with distances from the Taejon underground food cold storage pilot cavern. Claesson's solution, which is based on constant temperature boundary condition at the rock wall during a temperature decline step, showed relatively good agreement with temperature measurements in the rock mass in order of average error difference, 0.89$\^{C}$ without any adjustments on laboratory thermal properties to represent the rock mass. For the numerical model with heat flux through the rock wall, a boundary condition setting technique was newly proposed to overcome the difficulty of prescribing variable convective heat tranfer coefficient and far-field air temperature inside the cavern as they may be certainly changed according to the cooling-down time. The results showed also good agreement with measurements in order of average error difference, 1.58$\^{C}$, and were compared to those of the numerical model with fixed temperature at the rock wall. Finally, the most proper procedure to precisely predict the temperature profile around a cavern was proposed as a series of analysis steps including an analytical exact solution and numerical models.

• Molecular & Cellular Toxicology
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• v.3 no.3
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• pp.198-207
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• 2007

[ $^{18}F$ ]-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) scan has been found to reflect tumor aggressiveness and prognosis in various types of cancer. In this study, the gene expression profiles of glial tumors were evaluated to determine whether glial tumors with high $^{18}F$-FDG uptake have more aggressive biological potential than with low uptake. Surgical specimens were obtained from the 12 patients with glial tumors (4 males and 8 females, age range 42-68 years). The tumor samples were divided into two groups based on the $^{18}F$-FDG uptake PET scan findings: high $^{18}F$-FDG uptake (n=4) and low $^{18}F$-FDG uptake (n=8). The pathological tumor grade was closely correlated with the $^{18}F$-FDG uptake pattern: Glial tumors with high $^{18}F$-FDG uptake were pathologically Edmondson-Steiner grade III, while those with low uptake were grade II. The total RNA was extracted from the frozen tissues of all glial tumors (n=12), and adjacent non-cancerous tissue (n=3). The gene expression profiles were evaluated using cDNA microarray. The glial tumors with high $^{18}F$-FDG uptake showed increase expression of 15 genes compared to those with low uptake (P<0.005). Nine genes were down-regulated. Gene expression is closely related to cell survival, cell-to-cell adhesion or cell spreading; therefore, glial tumors with high $^{18}F$-FDG uptake appear to have more aggressive biological properties than those with low uptake.