• 한국초전도ㆍ저온공학회논문지
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• 제13권1호
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• pp.1-5
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• 2011

[ $CeO_2$ ]has been widely used for single buffer layer of coated conductor because of superior chemical and structural compatibility with $ReBa_2Cu_3O_{7-{\delta}}$(Re=Y, Nd, Sm, Gd, Dy, Ho, etc.). But, the surface of $CeO_2$ layer showed cracks because of the large difference in thermal expansion coefficient between metal substrate and deposited $CeO_2$ layer, when thickness of $CeO_2$ layer exceeds 100 nm on the biaxially textured Ni-3%W substrate. The deposition rate has been limited to be less than 6 $\AA$/sec in order to get a good epitaxy. In this research, we deposited $CeO_2$ single buffer layers on biaxially textured Ni-3%W substrate with 2-step process such as thin nucleation layer(>10 nm) with low deposition rate(3 $\AA$/sec) and thick homo epitaxial layer(>240 nm) with high deposition rate(30 $\AA$/sec). Effect of deposition temperature on degree of texture development was tested. Thick homo epitaxial $CeO_2$ layer with good texture without crack was obtained at $600^{\circ}C$, which has ${\Delta}{\phi}$ value of $6.2^{\circ}$, ${\Delta}{\omega}$ value of $4.3^{\circ}$ and average surface roughness(Ra) of 7.2 nm within $10{\mu}m{\times}10{\mu}m$ area. This result shows the possibility of preparing advanced Ni substrate with simplified architecture of single $CeO_2$ layer for low cost coated conductor.

• 대한기계학회논문집B
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• 제33권7호
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• pp.486-494
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• 2009

One-dimensional modeling of $CH_4$/air premixed flame was conducted to validate the heat loss model and investigate NOx formation characteristics in the postflame region. The predicted temperature and NO concentration were compared to experimental data and previous heat loss model results using a constant gradient of temperature (100 K/cm). The following conclusions were drawn. In the heat loss model using steady-state heat transfer equation, the numerical results using the effective heat loss coefficient ($h_{eff}$) of $1.0\;W/m^2K$ were in very good agreement with the experiments in terms of temperature and NO concentration. On the other hand, the calculated values using the constant gradient of temperature (100 K/cm) were lower than that in the experiments. Although the effects of heat loss suppress NO production near the flame region, a significant difference in NO concentration was not found compared to that under adiabatic conditions. In the postflame region, however, there were considerable differences in NO emission index as well as the contribution of NO formation mechanisms. In particular, in the range of ${\phi}\;{\geq}\;0.8$, the prompt NO mechanism plays an important role in the NO reduction under the adiabatic condition. On the other hand, the mechanism contributes to the NO production under the heat loss conditions.

• 기술발표회
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• 통권2006호
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• pp.320-328
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• 2006

In this test, there was two dimensional model loading test implemented for analysis with respect to the problem of evaluating bearing capacity and the application range on the dredged and reclaimed ground. It was got following conclusion through comparison of button's and Brown&Meyerhof"s equation with experimental result that was obtained by 2 dimensions model loading test. For the difference between average undrained shear strength by 2/3B of loading board width and under 2/3B is more than ${\pm}$ 50%, application of Nc(coefficient of bearing capacity was used in that case $\phi$=0 analysis is considered in the single layer) was declined. Brown&Meyerhof(1969)'s equation was underestimated comparing with loading test result, while Button(1953)'s equation was overestimated comparing with loading test result applied dividing as double layers of upper dessication layer and lower soft layer about dredged and reclaimed ground. Also, bearing capacity factors, Nc that was calculated by using button's equation was estimated greatly about 1.7 times more than bearing capacity factors, Nc that was calculated by using Brown&Meyerhof's equation. Bearing capacity factors, Nc that was calcuated by using Brown&Meyerhof's and Button's equation was evaluated each 2.3-3.6 times, 1.3-2.1 times smaller than bearing capacity factors, Nc5.14 that was calcuated by using Meyerhof's equation in case of unit layer.

• 한국전기전자재료학회논문지
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• 제22권1호
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• pp.22-28
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• 2009

We investigated the sintering and electric properties of ZnO-1.0 at% $TeO_2$ (ZT1) and 1.0 at% Mn-doped ZT1(ZT1M1) system. $TeO_2$ itself melts at $732^{\circ}C$ in air but forms the $ZnTeO_3$ or $Zn_2Te_3O_8$ phase with ZnO as increasing temperature and therefore retards the densification of ZnO to $1000^{\circ}C$. In ZT1M1 system, also, the densification of ZnO was retarded up to $1000^{\circ}C$ and then reached > 90% of theoretical density above $1100^{\circ}C$. It was found that a good varistor characteristics(nonlinear coefficient $a{\sim}60$) were developed in ZT1M1 system sintered at $1100^{\circ}C$ due to Mn which known as improving the nonlinearity of ZnO varistors. The results of C-V characteristics such as barrier height (${\Phi}_b$), donor density ($N_D$), depletion layer (W), and interface state density ($N_t$) in ZT1M1 ceramics were $1.8{\times}10^{17}cm^{-3}$, 1.6 V, 93 nm, and $1.7{\times}10^{12}cm^{-2}$, respectively. Also we measured the resistance and capacitance of grain boundaries with temperature using impedance and electric modulus spectroscopy. It will be discussed about the stability and homogeneity of grain boundaries using distribution parameter ($\alpha$) simulated with the Z(T)"-logf plots.

• 한국농공학회논문집
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• 제61권6호
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• pp.67-72
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• 2019

This study compared the theory of a culvert spacing and analytical results of the seepage flow for the subsurface drainage. i) If culvert spacing (Sc) is within 5 m, the unit drainage (q) is very larger; in contrast, if Sc is 5 m or more, there is very little drainage in the middle between drains. Therefore, the drain spacing should be within 5 m to ensure high drainage efficiency. ii) Since the planned culvert drainage increases linearly with the soil's permeability coefficient (k), k must be taken into account when determining the drain diameter by the planned culvert drainage. iii) As a result of analyzing the drainage performance of the absorbing culvert, the drainage performance is sufficient with the diameter of the corrugated drain pipe Dc = 50 mm at the length of the drain Lc = 100 m. iv) Therefore, if the drain spacing (Sc) is less than 5 m using the low-cost non-excavated drainage pipe method (${\Phi}50mm$ the corrugated drain pipe and fiber mat) rather than the conventional trench drain method (Sc > 10 m, Dc > 100 mm), uniform and high drainage efficiency can be ensured as well as low construction cost. v) The sub-irrigation+drainage culvert requires narrower drain spacing (Sc < 2-3 m) for irrigation. As a result of examining the condition of 35 mm in diameter (Dc) and 2~3 m in drain spacing, it is possible to apply the non-excavated drainage pipe method to the sub-irrigation+drainage culvert because drainage performance is sufficient at the drain length Lc = 50 m.

• 대한간호학회지
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• 제54권1호
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• pp.1-17
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• 2024

Purpose: The significance of the healthcare industry has grown exponentially in recent years due to the impact of the fourth industrial revolution and the ongoing pandemic. Accordingly, this study aimed to examine domestic healthcare-related patents comprehensively. Big data analysis was used to present the trend and status of patents filed in nursing. Methods: The descriptive review was conducted based on Grant and Booth's descriptive review framework. Patents related to nursing was searched in the Korea Intellectual Property Rights Information Service between January 2016 to December 2020. Data analysis included descriptive statistics, phi-coefficient for correlations, and network analysis using the R program (version 4.2.2). Results: Among 37,824 patents initially searched, 1,574 were selected based on the inclusion criteria. Nursing-related patents did not specify subjects, and many patents (41.4%) were related to treatment in the healthcare delivery phase. Furthermore, most patents (56.1%) were designed to increase effectiveness. The words frequently used in the titles of nursing-related patents were, in order, "artificial intelligence," "health management," and "medical information," and the main terms with high connection centrality were "artificial intelligence" and "therapeutic system." Conclusion: The industrialization of nursing is the best solution for developing the healthcare industry and national health promotion. Collaborations in education, research, and policy will help the nursing industry become a healthcare industry of the future. This will prime the enhancement of the national economy and public health.

• 한국농공학회지
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• 제17권1호
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• pp.3642-3654
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• 1975

The purpose of this thesis is to derive a unit hydrograph which may be applied to the ungaged watershed area from the relations between directly measurable unitgraph properties such as peak discharge(qp), time to peak discharge (Tp), and lag time (Lg) and watershed characteristics such as river length(L) from the given station to the upstream limits of the watershed area in km, river length from station to centroid of gravity of the watershed area in km (Lca), and main stream slope in meter per km (S). Other procedure based on routing a time-area diagram through catchment storage named Instantaneous Unit Hydrograph(IUH). Dimensionless unitgraph also analysed in brief. The basic data (1969 to 1973) used in these studies are 9 recording level gages and rating curves, 41 rain gages and pluviographs, and 40 observed unitgraphs through the 9 sub watersheds in Nak Oong River basin. The results summarized in these studies are as follows; 1. Time in hour from start of rise to peak rate (Tp) generally occured at the position of 0.3Tb (time base of hydrograph) with some indication of higher values for larger watershed. The base flow is comparelatively higher than the other small watershed area. 2. Te losses from rainfall were divided into initial loss and continuing loss. Initial loss may be defined as that portion of storm rainfall which is intercepted by vegetation, held in deppression storage or infiltrated at a high rate early in the storm and continuing loss is defined as the loss which continues at a constant rate throughout the duration of the storm after the initial loss has been satisfied. Tis continuing loss approximates the nearly constant rate of infiltration (${\Phi}$-index method). The loss rate from this analysis was estimated 50 Per cent to the rainfall excess approximately during the surface runoff occured. 3. Stream slope seems approximate, as is usual, to consider the mainstreamonly, not giving any specific consideration to tributary. It is desirable to develop a single measure of slope that is representative of the who1e stream. The mean slope of channel increment in 1 meter per 200 meters and 1 meter per 1400 meters were defined at Gazang and Jindong respectively. It is considered that the slopes are low slightly in the light of other river studies. Flood concentration rate might slightly be low in the Nak Dong river basin. 4. It found that the watershed lag (Lg, hrs) could be expressed by Lg=0.253 (L.Lca)0.4171 The product L.Lca is a measure of the size and shape of the watershed. For the logarithms, the correlation coefficient for Lg was 0.97 which defined that Lg is closely related with the watershed characteristics, L and Lca. 5. Expression for basin might be expected to take form containing theslope as {{{{ { L}_{g }=0.545 {( { L. { L}_{ca } } over { SQRT {s} } ) }^{0.346 } }}}} For the logarithms, the correlation coefficient for Lg was 0.97 which defined that Lg is closely related with the basin characteristics too. It should be needed to take care of analysis which relating to the mean slopes 6. Peak discharge per unit area of unitgraph for standard duration tr, ㎥/sec/$\textrm{km}^2$, was given by qp=10-0.52-0.0184Lg with a indication of lower values for watershed contrary to the higher lag time. For the logarithms, the correlation coefficient qp was 0.998 which defined high sign ificance. The peak discharge of the unitgraph for an area could therefore be expected to take the from Qp=qp. A(㎥/sec). 7. Using the unitgraph parameter Lg, the base length of the unitgraph, in days, was adopted as {{{{ {T}_{b } =0.73+2.073( { { L}_{g } } over {24 } )}}}} with high significant correlation coefficient, 0.92. The constant of the above equation are fixed by the procedure used to separate base flow from direct runoff. 8. The width W75 of the unitgraph at discharge equal to 75 per cent of the peak discharge, in hours and the width W50 at discharge equal to 50 Per cent of the peak discharge in hours, can be estimated from {{{{ { W}_{75 }= { 1.61} over { { q}_{b } ^{1.05 } } }}}} and {{{{ { W}_{50 }= { 2.5} over { { q}_{b } ^{1.05 } } }}}} respectively. This provides supplementary guide for sketching the unitgraph. 9. Above equations define the three factors necessary to construct the unitgraph for duration tr. For the duration tR, the lag is LgR=Lg+0.2(tR-tr) and this modified lag, LgRis used in qp and Tb It the tr happens to be equal to or close to tR, further assume qpR=qp. 10. Triangular hydrograph is a dimensionless unitgraph prepared from the 40 unitgraphs. The equation is shown as {{{{ { q}_{p } = { K.A.Q} over { { T}_{p } } }}}} or {{{{ { q}_{p } = { 0.21A.Q} over { { T}_{p } } }}}} The constant 0.21 is defined to Nak Dong River basin. 11. The base length of the time-area diagram for the IUH routing is {{{{C=0.9 {( { L. { L}_{ca } } over { SQRT { s} } ) }^{1/3 } }}}}. Correlation coefficient for C was 0.983 which defined a high significance. The base length of the T-AD was set to equal the time from the midpoint of rain fall excess to the point of contraflexure. The constant K, derived in this studies is K=8.32+0.0213 {{{{ { L} over { SQRT { s} } }}}} with correlation coefficient, 0.964. 12. In the light of the results analysed in these studies, average errors in the peak discharge of the Synthetic unitgraph, Triangular unitgraph, and IUH were estimated as 2.2, 7.7 and 6.4 per cent respectively to the peak of observed average unitgraph. Each ordinate of the Synthetic unitgraph was approached closely to the observed one.

• 한국물환경학회지
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• 제33권4호
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• pp.460-473
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• 2017

In order to certificate the contamination assessment of heavy metals in surface sediments from the Nakdong river. Surface sediments were collected of 24 sampling sites (main 14st., tributary 10st.) and analyzed for grain size heavy metals contents. Study area mainly composed of sand (avg. 94.1%) and mean grain size was $1.46{\Phi}$ on average. Heavy metals contents (avg. Al: 12.5%, Zn; 74.4, Cr: 45.3, Li: 26.0, Pb: 17.1, Ni: 10.5, Cu: 7.8, Cd: 0.22 mg/kg) were relatively high contents in the composed of fine sediments. In addition, the results of pearson's correlation coefficient showed that most heavy metals and grain size (silt and clay) were highly correlated. The contents of Zn (6st.) and Ni (1st.) evaluated as moderately polluted, Zn (6st.) evaluated as LEL when compared with sediment quality standard of USEPA and Ontario sediment quality guidelines. Most heavy metals contents were I levels that dose not affected the benthos when compared with sediment pollution evaluation standard of NIER. The results of EX, EF, Igeo and CF showed the contents of Zn, Pb and Cd exceed the background contents and distributing of anthropogenic pollution and evaluated as moderately polluted level. And Nm-08 were relatively high level of contamination in the study area. However as results of PLI (less than 1), all sampling sites were evaluated unpolluted level.

• 대한예방한의학회지
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• 제21권2호
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• pp.23-34
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• 2017

Objectives : The aim of this study was to survey the present utilization of pattern identification(PI) by chronic disease and using PI system in the clinical field among Korean medicine doctors. Methods : This survey was conducted from Oct. 1 to Oct. 31, 2014 by face-to-face interview using structured questionnaire. The subjects were 400 Korean medicine doctors who worked in hospitals or clinics. The questionnaire consisted of whether use clinical experience by chronic disease and the utilization of PI, the utilization of PI systems, the PI utilization rate, and the correlation between utilization PI and so on. General elements consisted of sex, age, clinical experience, place of work, district and so on. Results and Conclusions : This study revealed that clinical experience by chronic disease used 24.0-90.8%. The most chronic diseases were chronic fatigue and chronic pain, and least disease was cancer. Experience of the utilization of PI among Korean medicine doctors who have clinical experience was 87.8-97.1%. Also, the most utilized disease was chronic gastritis & gastric ulcer, and least disease was dyslipidemia. In this case, the most common cases were using the one PI between the utilization of PI systems, and the utilization ratio of Visceral PI was the highest. Phi coefficient between the PI systems in chronic diseases divided into positive correlation and negative correlation. The correlation of dementia between Triple energizer PI and Six excesses PI was the highest at positive correlation, and the frequency of occurrence between Defense, Qi, Nutrient and Blood PI was the highest at positive correlation. The correlation of osteoarthropathy between Meridian and Collateral PI and Sasang Constitutional Medicine was the highest at negative correlation. Also the frequency of occurrence between Qi, Blood, Fluid and Humor PI and Sasang Constitutional Medicine was the highest at negative correlation. We hope that additional studies on systematic PI research of chronic disease which needed to be in korean oriental medicine and meet the needs of clinical consumer continue based on this study.

• 한국전기전자재료학회논문지
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• 제26권1호
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• pp.38-43
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• 2013

In this study we aims to examine the effects of $Co_3O_4$ and NiO doping on the defects and electrical properties in ZnO-$Bi_2O_3-Sb_2O_3$ (Sb/Bi=0.5) varistors. It seemed to form ${Zn_i}^{{\cdot}{\cdot}}$(0.20 eV) and ${V_o}^{\cdot}$(0.33 eV) as dominant defects in Co and Ni co-doped ZBS system, however only ${V_o}^{\cdot}$ appeared in Co- or Ni-doped ZBS. Even though the same defects it was different in capacitance (1.5~4.5 nF) and resistance ($0.3{\sim}9.5k{\Omega}$). The varistor characteristics were improved with Co and Co+Ni doping (non-linear coefficient, ${\alpha}$= 36 and 29, relatively) in ZBS. The various parameters ($N_d=1.43{\sim}2.33{\times}10^{17}cm^{-3}$, $N_t=1.40{\sim}2.28{\times}10^{12}cm^{-2}$, ${\Phi}b$=1.76~2.37 V, W= 98~118 nm) calculated from the C-V characteristics in our systems did not depend greatly on the type of dopant, which were in the range of a typical ZnO varistors. It should be derived a improved C-V equation carefully for more reliable parameters because the variation of the varistor capacitance as a function of the applied dc voltage is depend on the defect, frequency, and temperature.