• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.2
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• pp.68-75
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• 1978

Experiments were conducted to find out the optimum seeding rate and amounts of fertilizer application for seedling growth of five for machine transplanting. Number of leaves of seedlings increased as seeding rate decreased, but there was no significant differences in leaf number among fertilizer levels. At a seeding rate higher than 100g/box. number of leaves was less than 4.5, but more than five leaves were developed at a seeding rate of 50g/box.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.4
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• pp.109-120
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• 2003

The state-of-art of curved box girder bridge with cross section design has advanced in various area. In these days, several analytical techniques for behaviors of curved box girder bridges cross section are available to engineers. The transfer matrix method is extensively used for the structural analysis because its merit in the theoretical background and applicability. The technique is attractive for implementation on a numerical solution by means of a computer program coded in Fortran language with a few elements. To demonstrate this fact, it gives good results which compare well with finite element method. Therefore, this paper proposed the static analysis method of curved box bridge with cross section by transfer matrix method based on pure-torsional theory and the optimal span ratio/variable cross section ratio of 3 span continuous curved box girder bridge.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.211-220
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• 2022

This paper proposes a green closed-loop supply chain network (GCSN) for optimizing closed-loop supply chains. The GCSN focuses on the application of the recycling express box in logistics circulation, accelerates the standardization of logistics operations and the use of express packaging in e-commerce companies, and promotes the reduction and greening of recycling express box in the e-commerce industry. The GCSN is represented as a mathematical formulation and implemented using LINGO. Greening, environmental protection, and wisdom are the general trends for promoting the growth of the e-commerce industry. Meanwhile, the price of raw materials has increased owing to a shortage of resources, which emphasizes the need for e-commerce enterprises to develop green packaging. Therefore, this study considers the shared circular packaging launched by e-commerce enterprises as the research object, and integrates the problem of facility positioning and path planning in the logistics system. The conclusion summarizes the significance of this study.

• Journal of the Mineralogical Society of Korea
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• v.23 no.4
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• pp.367-375
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• 2010

Understanding the interactions between earth materials and fluids is essential for studying the diverse geological processes in the Earth's surface and interior. In order to better understand the interactions between earth materials and fluids, we explore the effect of specific surface area and porosity on structural parameters of pore structures. We obtained 3D pore structures, using random packing simulations of porous media composed of single sized spheres with varying the particle size and porosity, and then we analyzed configurational entropy for 2D cross sections of porous media and cube counting fractal dimension for 3D porous networks. The results of the configurational entropy analysis show that the entropy length decreases from 0.8 to 0.2 with increasing specific surface area from 2.4 to $8.3mm^2/mm^3$, and the maximum configurational entropy increases from 0.94 to 0.99 with increasing porosity from 0.33 to 0.46. On the basis of the strong correlation between the liquid volume fraction (i.e., porosity) and configurational entropy, we suggest that elastic properties and viscosity of mantle melts can be expressed using configurational entropy. The results of the cube counting fractal dimension analysis show that cube counting fractal dimension increases with increasing porosity at constant specific surface area, and increases from 2.65 to 2.98 with increasing specific surface area from 2.4 to $8.3mm^2/mm^3$. On the basis of the strong correlation among cube counting fractal dimension, specific surface area, and porosity, we suggest that seismic wave attenuation and structural disorder in fluid-rock-melt composites can be described using cube counting fractal dimension.

• Investigative Magnetic Resonance Imaging
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• v.5 no.1
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• pp.33-37
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• 2001

Purpose : The water exchange rate between bulk water and bound water is an important parameter in deciding the efficiency of paramagnetic contrast agents. In this study, we evaluated the water exchange rates of various Gd-chelates using oxygen-17 NMR technique. Material and Methods : The samples (Gd-DTPA, Gd-DTPA-BMA, Gd-DOTA, Gd-EOB-DTPA) were prepared by mixing 5% $^{17}O-enriched$ water (Isotech, USA). The pH of the samples was adjusted to physiological value [pH=7.0] by buffer solution. The variable temperature $^{17}O-NMR$ measurements were performed using Bruker-600 (14.1 T, 81.3 MHz) spectrometer. Bruker VT-1000 temperature control units were used to stabilize the temperature. The $^{17}O$ spin-spin relaxation times (T2) were measured using Carr-Purcell-Meiboom-Gill (CPMG)I pulse sequence with 24 echo trains. The variable temperature T2 relaxation data were then fitted into Solomon-Bloembergen equations using least square fit algorithm to estimate the water exchange times. Results : From the measured $^{17}O-NMR$ relaxation rates, the determined water exchange rates at 300K are $0.42{\;}{\mu}s$ for Gd-DTPA, $1.99{\;}{\mu}s$ for Gd-DTPA-BMA, $0.27{\;}{\mu}s$ for Gd-DOTA, and $0.11{\;}{\mu}s$ for Gd-EOB-DTPA. The Gd-DTPA-BMA showed slowest exchange whereas Gd-EOB-DTPA had fastest water exchange rate. In addition, it was found that the water exchange rates (${\tau}_m$) of all samples had exponential temperature dependence with different decay constant. Conclusion : $^{17}O-NMR$ relaxation rate measurements, when combined with variable temperature technique, provide a solid tool for studying water exchange rate, which is very important in investigating the detailed mechanism of relaxation enhancement effect of the paramagnetic contrast agents.

• Journal of the Korean Magnetics Society
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• v.9 no.3
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• pp.127-130
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• 1999

The magnetism and electronic structure of Ru monolayer with square lattice is investigated using the FLAPW band method. The dependence of total energies on the lattice constant was calculated for three magnetic states, i.e.,para-,ferro-, and antiferromagnetic ones. It was found that there is no energy difference between para-and antiferromagnetic states for all the lattice constant. The possibility of antiferromagnetism in square Ru monolayer is thus excluded. The ferromagnetic state is most stable for the lattice constants greater than 7.30 a.u. The energy minimum is found at the lattice constant of 6.53 a.u. Where it is paramagenetic. It is calculated that the magenetic moment is 2.49 ${\MU}_B$ at 7.72 a.u., which is close to the lattice constant of Ag. The magnetic moment is almost saturated to be ${\MU}_B$ at the lattice constant of 7.86 a.u.

• Journal of Digital Convergence
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• v.12 no.4
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• pp.419-425
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• 2014

The objective of this study is to estimate the inhibition of skin melanin formation by extract of Angelica koreana and Cnidium monnieri and the possibility of functional cosmetic materials through anti-irritation and stability test. The extract used in this experiment is White-$AK^{TM}$ and the INCI name is Osthole. The main component of White-$AK^{TM}$ was identified as coumarin and EC50 value was 2.7ppm by mouse melanoma B 16 cell test. White-$AK^{TM}$ showed inhibitory effects 100 times lower concentration than arbutin. The main mechanism for skin whitening effect thought to be inhibition of tyrosinase-related gene expression. The basic essence formulation of White-$AK^{TM}$ 5% solution applied to the skin showed the effect of relieving skin irritation. White-$AK^{TM}$ in an opaque container, under UV conditions for 4 weeks, and showed close to 100% recovery and 97% recovery under $50^{\circ}C$ for 4 weeks. Therefore, it is thought that White-$AK^{TM}$ which helps skin whitening, relieving skin irritation and stable in UV condition is able to be used as the functional component in the cosmetic formulation.

• Journal of the Korean Magnetics Society
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• v.19 no.4
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• pp.126-132
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• 2009

We have studied physical properties of MnAs thin films grown by Molecular-Beam Epitaxy as well as their post-growth annealing effects. The samples grown at $600^{\circ}C$ show the preferred crystal orientation of type-B independent of substrate whereas type-A is observed for the samples grown at below $200^{\circ}C$. The sample grown at $600^{\circ}C$ on GaAs(001) substrate is magnetized to only one direction even on the easy axis of magnetization. The magnetic properties are vastly enhanced after post-growth annealing for both MnAs/Si(001) sample with no ferromagnetism and ferromagnetic MnAs/GaAs(001) grown at $200^{\circ}C$.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.604-604
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• 2013

차세대 반도체 분야인 스핀트로닉스 소자의 필수적인 물질인 강자성-반도체 하이브리드 물질인 Dilute magnetic semiconductor (DMS)에 관한 연구가 최근 많은 관심을 가지고 있다. 그중에서 넓은 에너지 밴드 갭 에너지(3.37 eV)를 가지고 있고 상온에서 엑시톤 결합 에너지가 ~60 mV로 광전자 소자, 전계 디스플레이 에 응용이 가능한 물질인 ZnO는 최근에 전이금속을 도핑하여 상온에서 강자성 특성을 나타내어 활발한 연구가 이루어지고 있다. 그러나, 이 물질에 대한 특성과 자성의 원인 규명에 관한 연구는 논란이 되고 있다. 본 연구에서는 Mn이 도핑된 ZnO 나노 입자를 만들고, Mn 물질의 도핑 농도에 따른 ZnO 나노 입자의 구조, 크기 및 자기 구조를 측정하여 구조와 자성의 상관관계에 관한 연구하였다. ZnxMn1-xO 나노 입자는 화학적 졸-겔(sol-gel) 방법을 이용하여 준비하였다. ZnxMn1-xO 나노 입자의 크기 및 격자 구조적 특징은 XRD (X-ray diffraction)와 TEM (Transmission Electron Microscope), SEM (Scanning Electron Microscope), SANS (Small Angle Neutron Scattering)를 이용하여 측정하였고 물질의 자기적 특징은 SQUID를 이용하여 조사하였다. Mn 도핑이 증가함에 따라 격자간격이 커지고 나노 입자의 크기는 감소하였으며, Zn와 Mn의 성장 시, 비율이 9:1의 경우에 상온에서 강자성 특성이 나타남을 보았다. 그 이상의 Mn 도핑 비율에서는 상자성 특성이 나타남을 보았다. 본 연구를 통하여 스핀트로닉스 소자 응용을 위한 ZnO 나노 입자에 최적의 Mn 도핑 농도를 제시하고 나노 입자의 자기 특성 형성의 원인 및 모델을 제시하였다.

• Food Science and Preservation
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• v.23 no.2
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• pp.166-173
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• 2016

This study aimed to evaluate the commercialized packaging status of tomato and paprika, and to investigate the effect of different packaging materials on the quality of tomato and paprika during storage. Packaging statuses were surveyed at a department store, wholesale market, and supermarket in Seoul, Korea. Materials used for packaging tomato and paprika were cartons, polypropylene (PP), low-density polyethylene (LDPE), polystyrene (PS), and polyvinyl chloride (PVC). Tomato and paprika were packaged by using corrugated boxes, Styrofoam trays, PP film, and PVC film. The weight loss and hardness of non-packaged tomato and paprika were significantly different after 48 hr to the initial values (p<0.05). Box-packaged tomatoes had the lowest pH values and showed significantly higher soluble solid contents (p<0.05). However, there were no significant differences in among other packaging materials. For paprika, the ${\Delta}E$ values of PVC wrapping were higher than those of other packagings. Hence, the results demonstrated that a corrugated box with PP film and PP film bags with four holes plus wire-tying were most able to maintain the overall qualities of tomato and paprika, respectively, during storage.