• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.127-135
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• 2002

The accurate evaluation of settlement is important to every steps in the constructions involving soft soils. Relating with those constructions, especially, it has been emphasized recently that the influnce of secondary settlement is important. The ratio of $C_a/C_c$ and the surcharging tests can be applied collaboratively to predicting and reducing secondary consolidation. A series of incremental loading consolidation test and surcharging tests for undisturbed samples of Kunsan clay were performed in this study. As a result of the tests, the ratio of $C_a/C_c$ for the clay was found to be 0.0329. Also, the relationship between void ratio and $t/t_p$ was shown to be linear. Accordingly, the secondary compression index, $C_a for a long term loading had a constant value regardless of time. When the total surcharge ratio was 0.4 and the dissipation ratio of excessive porewater pressure was in the range from 80% to 100%, secondary settlement was effectively reduced for Kunsan clay.

• Korean Chemical Engineering Research
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• v.59 no.2
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• pp.254-259
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• 2021

Optical and electrical characteristics of the fluorocarbon films deposited in a high-density C4F8 plasma under various source powers and pressures were investigated. The F/C ratio of the fluorocarbon film deposited in a high-density C4F8 plasma increased with increasing source power and decreasing pressure due to two-step deposition mechanism. The change in the F/C ratio of the film directly affected the optical and electrical characteristics of the fluorocarbon films deposited in a high-density C4F8 plasma. The refractive index of the fluorocarbon film increased with decreasing source power and increasing pressure contrary to the dependence of the film's F/C ratio on the source power and pressure. This was because the increase in the F/C ratio suppressed electronic polarization and weakened the network structures of the film. The resistivity of the fluorocarbon film showed the same behavior as its F/C ratio. In other words, the resistivity increased with increasing source power and decreasing pressure, resulting from stronger repellence of electrons at higher F/C ratios. This work offers the feasibility of the use of the fluorocarbon films deposited in a high-density C4F8 plasma as an alternative to low dielectric constant materials because the optical and electrical properties of the fluorocarbon film can be directly controlled by its F/C ratio.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.2
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• pp.153-158
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• 2012

Purpose: The purpose of this study was to evaluate the convergence accommodation to convergence (CA/C) ratio and to investigate relationships among age, accommodative amplitude and PD (interpupillary distance) of adults in their early twenties with normal binocular vision. Methods: 44 subjects (mean age, $21.75{\pm}1.16$ years) with healthy eyes were examined. The CA/C ratios were measured by using the difference of Gaussian (DOG) target with retinoscopy. Results: The mean CA/C ratio was $0.052{\pm}0.017$ D/$\Delta$. A moderate negative correction was present between CA/C ratio and age (r = -0.50, p = 0.0005), and a highly positive correction was found between CA/C ratio and accommodative amplitude (r = 0.79, p<0.0001). There was no relation between PD and CA/C ratio. Conclusions: The CA/C ratio presented was mean value for adults in their early twenties with healthy eye between 19 and 25 years of age. There was a high correlation between accommodative amplitude and CA/C ratio. Therefore, the CA/C ratio will be useful basic information for comparison in age, gender and binocular anomalies with similar data from other countries.

• Korean Journal of Plant Resources
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• v.11 no.2
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• pp.131-135
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• 1998

Cathamus tinctorius, Coptis japonica and Asarum sieboldii were tested as substrate for the production of Flammulina velutipes. Among the C. tinctoris , C. japonica and A. sieboldii , C. tinctoris was the best substrate for the production of fruitbody. The effects of addition of C. tinctoris to sawdust substrate resulted in the increased mycelial growth on inoculum culture, 3.1% in ratio of fully culture and shorted one day in culture period. C. tinctoris was decreased 6.1% in ratio of fully culture, 11.0% in ratio of fruitbody productive culm. The addition of C.tinctoris, C.japonica to sawdust substrate increased 134.6%, 114.1% on the yield of the mushroom fruitbody respectively . But A. sieboldii decreased the mycelial growth and pineheading ratio delayed the production of fruitbody.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.3
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• pp.167-173
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• 2023

This study assesses the urine microalbumin to urine creatinine ratio (uACR) with uric acid and the association with the high-density lipoprotein cholesterol (UA/HDL-C) ratio in Korean adults. Data from the 2019 Korean National Health and Nutrition Examination Survey was procured and included 5,845 adults aged 20 years or older. Several key findings were obtained in the present study. After adjusting for the related variables (age, gender, hypertension, obesity, type 2 diabetes mellitus, and chronic kidney disease), the uACR was found to be positively associated with the quartiles of the UA/HDL-C ratio (P=0.002). Moreover, after adjusting for related variables, the odds ratio (OR) of albuminuria (uACR≥30.0 mg/g) was not significant in quartile 2 (Q2) (OR, 1.015; 95% confidence interval [CI], 0.757~1.361) and Q3 (OR, 1.090; 95% CI, 0.811~1.465) but was significantly higher in Q4 (OR, 1.416; 95% CI, 1.044~1.921) as compared to Q1 of the UA/HDL-C ratio. We conclude that since the UA/HDL-C ratio is positively associated with albuminuria in Korean adults, an increased UA/HDL-C ratio could be applied as a useful measure to assess albuminuria in Korean adults.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.1
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• pp.78-86
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• 1992

This paper aims at investigating the effect of steel ratio and the magnitude of edge-ratio on the mechanical characteristics of reinforced concrete ring sector plate. The influence of steel bars was taken into account by coupling stiffness matrix of the steel bar element with that of the concrete plate element without dealing with separate element of steel bar and by establishing the composite stiffness matrix, which leads to the desirable result which does not increase th number of element could be obtained. Through case studies with 6 cases various steel ratios in ring sector plate supported at four edges and 4 cases with different open angles, the influence of the steel ratio was examined. A numerical analysis to find out the effect of the steel ratio d ue to above mentioned cases was carried out by 4 boundary conditions ; all edges clamped (B.C-1), all edges simply supported (B.C-2), curvilinear two edges clamped and other edges free (B.C-3) and curvilinear two edges simply supported and other edges free(B.C-4). The main results obtained are summarized as follows : 1. The effect of steel ratio on the magnitude of lateral deflection and x-directional bending moment at the center of sector plate and the midpoint of outer and inner curvilinear edges is almost the same up to $30^{\circ}$ of open angle. Beyond $30^{\circ}$ of the angle, the larger the angle, the greater the effect of ratio. 2. In design works using balanced steel ratio, the effect of steel bar can be ignored. But for larger open angles, especially greater than $90^{\circ}$, it proves desirable to consider the effect of steel bar. 3. The effect of the arc length of center circle/straight edge on lateral deflection and bending moment is remarkable in B.C-2. For larger open angle, the effect is also noted except for B.C-3 which turn out hardly affected. 4. The effect of the radius of curvature/straight side length on lateral deflection and x-directional bending moment is noted in B.C-2. As open angle increases, B.C-1 and B.C-3 almost agree and B.C-2 approaches B.C-4.

• Journal of Environmental Science International
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• v.23 no.11
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• pp.1835-1842
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• 2014

The goal of this study was to evaluate micro-bubble concentration ($C_{air}$) in water by air/water ratio (A/W ratio) with a micro-bubble generating pump. The estimation of micro-bubble concentration is based on the balance of inlet/outlet air and water flow rate. On net A/W ratio to be generated micro-bubble, we found that the obtained the $C_{air}$ are shown as a function of discharge pressure ($P_g$) of the micro-bubble generating pump. The correlation of the $C_{air}$ and the $P_g$ ($C_{air}=3.261P_g-1.754$) was adequately described by the least square methods with a high correlation coefficient (r = 0.9459) and calculated values fit the experimental data quite well. The $C_{air}$ was lower than theoretical dissolved air concentration ($C_{aq}$) calculated by Henry's law. The $C_{air}$ for being operated the micro-bubble generating pump was 6.75 - 39.53 mL/L, however, we found that the optimum of the $C_{air}$ to generate micro-bubble was the range from 10 to 12 mL/L.

• Journal of the Korean Ceramic Society
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• v.33 no.10
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• pp.1163-1169
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• 1996

The effects of borax on the phase formation of C2S, C4A3 and $\alpha$'-C2S phases. It has negative effects on formation of C4A3 And it lowers the forming temperature of C4AF. It also has been found that borax improves the clinkerization of MBC. In the MBC clinker with borax 3% C2S have larger and more irregular shapes, larger C/S mole ratio and C4A3 have smaller size larger C/ molr ratio than in the clinker without borax.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.2 s.233
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• pp.263-270
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• 2005

An experimental study was performed to investigate the effects of partially premixing, varying the equivalence ratios from $0.79{\sim}{\infty}$, on NOx emissions and chemiluminescence of excited $OH^{\ast},\;CH^{ast}\;C_2^{\ast}$ radicals in laminar partially premixed flames. the signal from the electronically excited state of $OH^{\ast},\;CH^{ast}\;C_2^{\ast}$ was detected through a band pass filter with a photo multiplier tube, which are processed to the intensity ratio ($C_2^{\ast}/CH^{\ast},\;C_2^{\ast}/OH^{\ast},\;and\;CH^{\ast}/OH^{\ast}$) to reveal the correlation with local equivalence ratio. And measurements of NOx emission were made to investigate the relationship between visible flame appearance, chemiluminescence, and EINOX. The results demonstrated that (1) the flames at ${\phi}<1.59$ exhibited classical double flame structure, at ${\phi}>4.76$, the flames exhibited diffusion flame structure, and the intermediate flames at $1.59<{\phi}<4.76$ was a merged flame, (2) the $OH^{\ast}$ peak was located inside the $CH^{\ast}\;and\;C_2^{\ast}$ radical for all measured conditions and the emission intensity ratio of $C_2^{\ast}/CH^{\ast}\;and\;C_2^{\ast}/OH^{\ast}$ were identified as good marker for local equivalence ratio over a range of ${\phi}=0.79{\sim}1.2\;and\;CH^{\ast}/OH^{\ast}\;is\;0.79<{\phi}<1.9$. However, it was difficult to predict the equivalence ratio in partially premixed flames using this system for ${\phi}>2.38$, (3) the minimum NOX emission index (EINOx) is obtained for a equivalence ratio of 3.19 in the intermediate flames.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.10
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• pp.41-50
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• 1998

In this study, to investigate a characteristics of slip ratio control of H.C.U for ABS, half car model tester were developed and a new H.C.U. was compactly designed comparing to the commercical H.C.U. for ABS. In half car model tester, variable inertia wheel has been used to load the car weights and braking forces according to the road surface conditions which were realized by pneumatic cylinder. And solenoid valves using P.W.M. (Pulse Width Modulation) method were installed in the new H.C.U The slip ratio characteristics of tire had been measured using half car model tester and the results were used in the control simulation for a new H.C.U.