• Magazine of the Korean Society of Agricultural Engineers
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• v.18 no.1
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• pp.4011-4020
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• 1976

본논문은 북해도대학심사학위논문으로 총면수 143면인 영문으로 되어 있고 도 48, 표 7, 문묵 66부도, 부표 20면이있음. Plow는 옛부터 발달한 농구이기 때문에 많은 연구가 행하여졌지만 복잡한 물리성을 가준 토양을 대상으로 하는 기계이기 때문에 미해결의 문제도 적지않다. 이견인저항에 대하여 토양의 종류 및 조건을 변경하면서 실제의 포장에서 조직적으로 행한 실험은 극히 적고, 하물며 우리나라의 쟁기에 관한 연구는 거의없다. 본논문은 쟁기의 특징을 구명하고, 그의 개량, 발달에 기여하기 위한 기기자료를 획득코저 실시한 것이다. 1. 쟁기와 플라우의 구조 및 그의 차이 특징을 명백히하고 이체에 걸리는 각종의 저항의 내용 또는 그 비율등에 대하여 과거의 연구성과를 소개하였다. 2. 발달사 ; 플라우는 B.C. 2000년경에 녹각, 목지의 인력용의 경운용구에서 발달하고, 동양이도 기원은 대체로 같고 발달과정이 다를 뿐이다. 쟁기는 양자강연안에 기원을 가진 지나이가 신라와 백제에 도입되여 차차 발달하고, 지역적인 특징을 가지게 되었다. 3. 본장은 쟁기의 견인력에 관한 이론적해석을하고, 쟁기의 진행에 의해 층상으로 전단되는 전단저항을 구하고 쟁기의 표면 및 지측판과 토양과의 마찰력, 그리고 토양의 이동의 관성력을 쟁기의 견인저항에 관련되는 주요한 "힘"으로 생각하고 진행방면, 수직방면의 힘의 성분의 평형을 고려하여 식 10. 12를 유도 하였다. 4. 본장에서는 실험계획, 방법 공시기, 공시포장등을 기록하고, 축력용의 쟁기와 플라우를 사용하여 전지 4종 답 2종의 포장에서 실험하는데 견인력계와 자동경심측정기를 사용하였다. 5. 실험결과 및 고찰; 경심과 견인저항 Dp와의 관계는 식 10. 12와 갈이 표시되고, 실제의 제치를 대입하여 이론식을 유도하였으니 직선에 가까운 관계가 있고, 실험결과는 조금 곡선에 가까워졌다. 그리고, 토양의 물리성이 견인력Dp에의 영향을 세밀히 검토하였다. 쟁기의 견인비저항에 있어서도 식 12에서 {{{{K=AT+ { B} over {T } +C}}}}로 표시할수 있기 때문에 최소치를 표시하는 경심이 존재하고 이값은 쟁기나 플라우폭의{{{{ { 1} over {2 } }}}} 즉 10m정도이고 쟁기는 비저항이 0.llkg/$\textrm{cm}^2$에서 0.39kg/$\textrm{cm}^2$이였다. 그러나 이 비저항도 토양의 물리성이 많은 영향을 미치고 있다. 6. 요약 및 결론 ; 이상의 장에서 검토 고찰한 결과만을 기재하고 플라우는 쟁기에 비해 견인저항 및 비저항이 논에서나 밭에서 대로 나타난 것이 특이하다. 이상의 내용을 지면관계로 3회에 거쳐 요약 발표합니다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.6
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• pp.526-530
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• 1994

This study was conducted to investigate photosynthetic response to four sequential air influx rate with rice(Oryza sativa L.)plants moved from a natural condition to constant condition with automatic regulation selected environmental variables on 13th~15th days after anthesis. In time course of photosynthetic response to increasing air influx rate(200-280-360-440 ml / min.), stomatal conductance decreased rapidly at the beginning after treatment and then oscillated with a free-running period of a approximately 1 hour to 1 hour 30 minutes until reached up to steady-state condition. Similar change was also observed $CO_2$ assimilation rate. Stomatal conductance decreased throughout the air influx rate sequence, but the rate of decrease was similar to the decrease in $CO_2$ assimilation rate observed under continuous air influx rate conditions. In starch granules during grain filling period under air influx rate(440 ml / min.) , compound starch granules were loosing and a number of hollows were observed in surface of single starch granules. Evidences from several approaches indicate that synchronization of stomatal conductance and$CO_2$ assimilation rate was closely inter-related tinder increase of air influx rate and increase of air influx rate influenced the$CO_2$ uptake in photosynthetic processes and compound starch granule, as 'end products' of photosynthesis.

• Clean Technology
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• v.17 no.2
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• pp.110-116
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• 2011

The dyeing of polyester fiber with two different disperse dyes (Disperse Red 60 and Disperse Yellow 54) was carried out using supercritical carbon dioxide ($SCCO_2$) as a dyeing medium at temperatures ranging from $50^{\circ}C$ to $90^{\circ}C$ and at pressures from 15 MPa to 30 MPa. The dye uptake of Disperse Red 60 on polyester fiber was found to increase with temperature at constant pressure and $SCCO_2$ density (700 kg/$m^3$). At $90^{\circ}C$ and 30 MPa, the dye uptake on polyester fiber increased with dyeing time and the saturation concentration of Red 60 was attained within 240 min, while a longer dyeing time was required for Yellow 54 to reach its saturation concentration. When dyestuff mixtures with mixing ratios of 0.01 to 9.0 (Red 60/Yellow 54) were used, the uptake ratio of the two dyes was found to be proportional to 0.26 power of their mixing ratio. Dyed fibers showed an orange color and the depth of the color depended upon the mixing ratio of the dyestuffs.

• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.4
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• pp.365-375
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• 2006

The structural analysis for the secondary lining of tunnels is generally performed by a frame analysis model. This model requires a ground loosening load estimated by some empirical methods, but the load is likely to be subjective and too large. The ground load acting on the secondary lining is due to the loss of the supporting function of the first support members such as shotcrete and rockbolts. Therefore, the equilibrium condition of the ground and the first support members should be considered to estimate the ground load acting on the secondary lining. Ground-lining interaction model, shortly GLI model, is developed on the basis of the concept that the secondary lining supports the ground deformation triggered by the loss of the support capacity of the first support members. Accordingly, the GLI model can take into account the ground load reflecting effectively not only the complex ground conditions but the installed conditions of the first support members. The load acting on the secondary lining besides the ground load includes the groundwater pressure and earthquake load. For the structural reinforcement of the secondary lining based on the ultimate strength design method, the factored load and various load combination should be considered. Since the GLI model has difficulty in dealing with the factored load, introduced in this study is the superposition principle in which the section moment and force of the secondary lining estimated for individual loads are multiplied by the load factors. Finally, the design method of the secondary lining using the GLI model is applied to the case of a shallow subway tunnel.

• Applied Chemistry for Engineering
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• v.5 no.3
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• pp.524-536
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• 1994

Chitosan is known to be a good biocompatible natural polymer. Polyethyleneglycol monomethacrylates(PEGM) were grafted onto chitosan and their reaction conditions and properties of the graft polymers obtained were estimated. Using ceric ammonium nitrate(CAN) as the initiator, the optimum condition for graft polymerization was determined amount of the initiator and monomer concentrations and reaction time. Grafting yields such as total conversion, the percentage of grafting and the efficiency of grafting were calculated and examined the optimum reaction condition for high grafting yields. The percentage of grafting and total conversion were maximum at condition that the concentration of initiator was $4{\sim}5{\times}10^{-3}M$, the concentration of monomer was 0.5~0.6M, the reaction time was 2~3 hours and the reaction temperature was about $40^{\circ}C$. Thermal characteristics, solubility for chitosan solvents and inherent viscosity of synthesized graft copolymers were investigated. In high initiator concentration, characteristics of chitosan were greatly diminshed. In case of inherent viscosities, chitosan-g-PE-90 was 2.81 dl/g, chitosan-g-PE-200, 3.01dl/g and chitosan-g-PE-350, 4.93dl/g. And a tendency of viscosity increase depending on the length of ethylene oxide residue was confirmed. Degree of swelling, tensile strength, elongation of membrane prepared from graft copolymers were determined. Properties of graft copolymers were affected by percentage of grafting and length of ethylene oxides residue in polyethylene glycol monomethacrylates. Tensile strength, elongation and degree of swelling of graft copolymers were remarkably improved than chitosan. As percentage of grafting increased, the amount of drug permeation was also increased.

• Applied Chemistry for Engineering
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• v.28 no.2
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• pp.153-157
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• 2017

Gel type internal electrolytes were synthesized by varying hydroxyethyl-cellulose (HEC) amounts and their durability and conductivity were measured. The ionic conductivity decreased as the content of HEC increased thus the internal electrolyte containing more than 12% of HEC could not be used as a reference electrode. Based on durability test results, as the HEC amount decreased carrier density resulting in increasing of the amount of KCl coming out of the porous membrane. Therefore in order to use long time at ballast water treatment systems, we selected 10% HEC for gel type internal electrolyte. The resolution test for total residual oxidants (TRO) was carried out using the TRO sensor and the gel type reference electrode made of 10% HEC. A 50 mV potential was applied to the TRO sensor for 30 sec and changes in the current were measured. It was confirmed that the TRO concentrations ranging from 0 to 15 mg/L could be separated at salinity conditions of 0.2~30 PSU. The results indicated that the TRO concentration at sea water and at fresh water was successfully measured by the TRO sensor constructed with the reference electrode using gel-type internal electrolyte of HEC.

• Journal of Energy Engineering
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• v.5 no.1
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• pp.56-64
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• 1996

The objective of this investigation is to establish the rejection characteristics of caesium and cobalt from radioactive liquid waste by chemical/ultrafiltration process. An extensive experimental investigation was conducted with inactive caesium and cobalt ions, utilizing ultrafiltration stirred cell. Caesium and cobalt could be effectively removed from waste solution using copper ferrocyanide and polyarcylic acid(PAA). The rejection dependence of the caesium was found to be a function of caesiun to potassium copper ferrocyanide feed molar ratio. The binding behavior of caesium on K$_2$Cu$_3$(Fe(CN)$\sub$6/)$_2$, particles was explained in terms of a Langmuir adsorption isotherm. When Cs/K$_2$Cu$_3$(Fe(CN)$\sub$6/)$_2$molar ratio was 1.5, the removal of caesium was the most efficient. The rejection efficiency of cobalt is dependent upon various parameters such as pH, cobalt concentration and PAA concentration. The rejection behavior of cobalt was explained in term of a equilibrium model taking into account the reaction between the ligand group, the proton and the cobalt ion. At the conditions of PAA/Co ratio of 2 and pH of 5.6, the removal of cobalt was over 90%. Also, the effect of chemical addition sequence for the simultaneously removal of caesiun and cobalt was discussed.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.124-132
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• 2016

In order to estimate the effect of flow distributors connected to an upper nozzle of CMT(Core Makeup Tank) on the thermal-hydraulic characteristics in the tank, a simplified 2 inch Small Break Loss of Coolant Accident(SBLOCA) was simulated by skipping the decay power and Passive Residual Heat Removal System(PRHRS) actuation. The CMT is a part of safety injection systems in the SMART (System Integrated Modular Advanced Reactor). Each test was performed with reliable boundary conditions. It means that the pressure distribution is provided with repeatable and reproducible behavior during SBLOCA simulations. The maximum flow rates were achieved at around 350 seconds after the initial opening of the isolation valve installed in CMT. After a short period of decreased flow rate, it attained a steady injection flow rate after about 1,250 seconds. This unstable injection period of the CMT coolant is due to the condensation of steam injected into the upper part of CMT. The steady injection flow rate was about 8.4% higher with B-type distributor than that with A-type distributor. The gravity injection during hot condition tests were in good agreement with that during cold condition tests except for the early stages.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.1 no.2
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• pp.15-22
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• 1991

When $YBa_2Cu_3Ox$ is liquid-phase sintered at $925^{\circ}C$ in $O_2$ for 16h, liquid pockets are entrapped within the grains. The liquid pockets show a thin parallelepiped shape with short edge lengths in the c axis, even after reannealing $925^{\circ}C$ in $O_2$ for 16h. All grains in contact with the liquid matrix show the same shape. However, when liquid-phase sintered at 925^{circ}C in $N_2$ for 16h, the grains dispersed in the liquid matrix show a thicker parallelepiped shape than in $O_2$, and their shape remains intact even after reannealing at $925^{\circ}C$ in $N_2$ for 16h. The effect of atmosphere on the grain shape is expected to be due to the variation of oxygen vacancy concentraion in $CuO_2$ plane of tetragonal unit cell.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.2
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• pp.171-182
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• 2007

For minimizing the effect on the focus of civil traffic and environment conditions related to the excavation at the traffic jamming points, an underground station tunnel was planned with 35.5 m in length and bigger area than $200\;m^2$ in sedimentary rock mass. It faced the case that the overburden was just under 13 m. Not based on a pattern design but on the case histories of similar projects and arching effect, the design of large section tunnel under shallow overburden was investigated on three design subjects which are shape effect on the section area, application method of support pressure, and supporting and tunnel safety. According to the mechanical effect from section shape, a basic design and a preliminary design was obtained, and then supporting method of large section was planned by the supporting of NATM and a pipe roof method for subsidence prevention and mechanical stability. From the comparative study between both designs, it was found that the basic design was suitable and acceptable for the steel alignment of tunnel lining, safety and the design parameter restricted by the limit considered as partition of the excavation facilities. Through the analysis result of preliminary design showing the mechanical stability without stress concentration in tunnel arch level, it also was induced that shape effect of the large section area and yielding load obtained from deformation zone in the surrounding rock mass of tunnel have to be considered as major topics for the further development of design technique on the large section tunnel.