• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6425-6431
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• 2015

Invertase, that hydrolyzes sucrose into glucose and fructose, plays a great role in carbohydrate reallocation between the photosynthetic source tissue and various sink tissues. Invertase also occurs in a variety of isoforms for various functions in plants. Insoluble invertases were extracted only in buffer solutions containing high concentrations of salt. Within these classes, acid invertase has an optimum activity at acidic pH (pH 4-5). Induction of insoluble acid invertase (INAC-INV) in leaf, stem, and root tissues in response to physical wounding has been investigated. To detect the localization of INAC-INV within the plant, immunolocalization has been performed. In this study, the accumulation of INAC-INV was noticeable to reach maximum levels on 72 hr after mechanical injuries. INAC-INV was induced in wounded leaves 3 times more than control leaves. Immunolocalization results showed that INAC-INV accumulated in wall appositions and intercellular spaces. INAC-INV was also localized at sieve cell walls in phloem tissues close to the site of wounding. Taken together, this study suggested that INAC-INV induction upon wounding injuries can play a role on responses to the high energy demand for wound healing process.

• Resources Recycling
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• v.25 no.1
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• pp.48-59
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• 2016

The earth has been warming due to $CO_2$ gas emissions from fossil fuel cars and a ship. So the hydrogen fuel cell vehicle(FCV) using hydrogen as a fossil fuel alternative energy is in the spotlight. Hyundai Motor Company of Korea and a car companies of the US, Japan, Germany is developing a FCV a competitive. Obtained hydrogen as a by-product of the coke plant, oil refineries, chemical plants of steel mill, coal is reacted with steam at high temperatures, methane gas, manufacture of high purity hydrogen Methane Steam Reforming and hydrogen detachable reforming method using the Pressure Swing Adsorption or Membrane Reforming technical or decomposition of water to produce electricity. Hydrogen is the electronic industry, metal and chemical industries, which are used as rocket fuel, etc. are used in factories, hospitals, home of the fuel Ene.Farm system or FCV. And a method of storing hydrogen is to store liquid hydrogen and a method for compressing normal hydrogen to the hydrogen container, by storing the latest hydride or Organic chemical hydride method is used to carry the hydrogen station. Korea is currently 13 hydrogen stations in place and in operation, plans to install a further 43 places.

• Journal of the Korean Institute of Gas
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• v.13 no.5
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• pp.1-6
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• 2009

This paper presents the fuel consumption effects of LPG vehicle depending on the atmospheric temperature, LP gas leakage of vaporizer, viscosity of engine oil and engine load conditions. The fuel consumption test results show that when the temperature of engine temperature rises, the fuel consumption efficiency increases in general. The fuel consumption efficiency for an atmosphere temperature of $24.2^{\circ}C$ is 13.6% high compared to that of $1^{\circ}C$. No leak vaporizer on fuel consumption efficiency is 5.3% high compared to that of the LP gas leak vaporizer. The fuel economy of new engine oils is just 1.1% high compared to that of used oils with a LPG vehicle mileage of 9,500km. This is not an influential factor compared with an atmospheric temperature and a LP gas leakage. The more important factors on the fuel consumption efficiency are driving conditions such as a rapid braking, abrupt start and fast acceleration. The test results indicate that the normal start is 32.3% high compared to that of an abrupt start and the fast acceleration is 10.8% high compared with that of an abrupt start. And the fuel consumption efficiency for a rapid braking is 18.3% higher than that of an abrupt start. These indicate that the driving condition is very important to reduce the fuel consumption rate.

• Tunnel and Underground Space
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• v.27 no.3
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• pp.161-171
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• 2017

Demand for high-grade limestone is increasing, but the production in the domestic mines has been limited due to the lack of systematic development plans and efforts to develop mining technology to improve the recovery ratio, transition to high-cost underground mining due to increasing social awareness of environmental protection, and the smallness of the domestic mining industry, etc. In this study in connection with this issue, an analysis on the recovery change by improvement of mining method was executed. 3D modeling technique was used to construct a 3D model. 3D model includes the geological structure, the limestone ore body and the underground pits and tunnels excavated at the Daepyeong District of Daesung MDI Donghae District. By using the 3D model, measured resources, reserves and ore recovery were evaluated from the results of pilot operation of the room and pillar hybrid mining method, which is a variant of room and pillar mining method. These results were compared with those obtained from the conventional mining method. The ore recovery obtained by hybrid mining method was found to be up to 71.6%, showing about 26%p. increase compared with the case of conventional mining method.

• Journal of the Korean Geosynthetics Society
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• v.13 no.4
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• pp.21-31
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• 2014

Recently, the research on renewable energy against depletion of fossil fuel have been actively carried out in the world. Especially, offshore wind turbines are very economical and innovative technology. However, offshore wind turbines experience large base moments due to the wind and wave loading, so the monopile with large diameter needs to be applied. For the economical design of the large diameter pile, it is important to consider the flexibility of the foundation to estimate the maximum moment accurately, based on studies conducted so far. In this paper, the foundation was modeled using the finite element method in order to better describe the large diameter effect of a monopile and the results were compared with those of p-y method. For the examples studied in this paper, the change in maximum moment was insignificant, but the maximum tilt angle from the finite element method was over 14% larger than that of p-y method. Therefore, the finite element approach is recommended to model the flexibility effect of the pile when large tilt angles may cause serviceability issues.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.328-328
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• 2007

Large area matrix-addressed image detectors are a recent technology for x-ray imaging with medical diagnostic and other applications. The imaging properties of x-ray pixel detectors depend on the quantum efficiency of x-rays, the generated signal of each x-ray photon and the distribution of the generated signal between pixels. In a phosphor coated detector the light signal is generated by electrons captured in the phosphor screen. In our study we simulated the lateral spread distributions for phosphor coupled detector by Monte Carlo simulations. Most simulations of such detectors simplify the setup by only taking the conversion layer into account neglecting behind. The Monte Carlo code MCNPX has been used to simulate the complete interaction and subsequent charge transport of x-ray radiation. This has allowed the analysis of charge sharing between pixel elements as an important limited factor of digital x-ray imaging system. The parameters are determined by lateral distribution of x-ray photons and x-ray induced electrons. The primary purpose of this study was to develop a design tool for the evaluation of geometry factor in the phosphor coupled optical imaging detector. In order to evaluate the spatial resolution for different phosphor material, phosphor geometry we have developed a simulation code. The developed code calculates the energy absorption and spatial distribution based on both the signal from the scintillating layer and the signal from direct detection of x-ray in the detector. We show that internal scattering contributes to the so-called spatial resolution drop of the image detector. Results from the simulation of spatial distribution in a phosphor pixel detector are presented. The spatial resolution can be increased by optimizing pixel size and phosphor thickness.

• Korean Journal of Optics and Photonics
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• v.9 no.4
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• pp.221-226
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• 1998

Ternary heavy metal oxide glasses in the $PbO-Bi_2O_3-Ga_2O_3$ system doped with $Er_2O_3$ were prepared and their spectroscopic properties, such as radiative transition probability, calculated and measured radiative lifetimes and cross-sections of 1.5 $\mu\textrm{m}$ and 2.7 $\mu\textrm{m}$ emissions were analyzed. Enhanced quantum efficiencies of some electronic transitions were evident mainly because of the low vibrational phonon energy ($~500cm^{-1}$) inherent in the host glasses. This seems to be the main reason for obtaining the 2.7 $\mu\textrm{m}$ luminescence which is normally quenched in the conventional oxide glasses. In addition, green and red fluorescence emissions were observed through the frequency upconversion processes of the 798 nm excitation. Non-radiative transition due to the multiphonon relaxation is a dominant lifetime-shortening mechanism in the 4f-4f transitions in $Er^{3+}$ ion except for the $^4S_{3/2}{\rightarrow}^4I_{15/2}$ transition where a non-radiative transfer to band-gap excitation of the host glasses is dominant. Melting of glasses under an inert gas atmosphere and (or) addition of the typical glass-network former into glasses is necessary in order to enhance the quantum efficiency of the transition.

• Membrane Journal
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• v.22 no.1
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• pp.72-76
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• 2012

$SF_6$ has an extremely high global worming potential (GWP). Therefore, there has been an effort to reduce the use of $SF_6$ and its emission into atmosphere. One possible solution for minimizing the use of $SF_6$ in electrical equipments is utilization of gas mixtures such as $SF_6/N_2$. The $SF_6$ concentration in the gas mixture varies from 10 to 60%. However, when the apparatus is repaired or dismantled, we have to recover $SF_6$ from the gas mixture. Since the boiling point of $SF_6$is low (${\sim}-60^{\circ}C$), the liquefaction method is difficult to apply. One possible alternative is the membrane separation technology. In this study, we investigated the $SF_6$ and $N_2$ permeation properties of 5 polymeric membranes. For example, permeability of $N_2$ in BOPP membrane at $25^{\circ}C$was 0.19 barrer, whereas that of $SF_6$ was only 0.0012 barrer, resulting in the selectivity of 158. An upper bound for $SF_6/N_2$ gas pair was suggested for the first time with n = -1.33 and k = 160 (barrer).

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.14-15
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• 2010

Recently there has been growing interest in topological insulators or the quantum spin Hall (QSH) phase, which are insulating materials with bulk band gaps but have metallic edge states that are formed topologically and robust against any non-magnetic impurity [1]. In a three-dimensional material, the two-dimensional surface states correspond to the edge states (topological metal) and their intriguing nature in terms of electronic and spin structures have been experimentally observed in bulk Bi1-xSbx single crystals [2,3,4]. However, if we want to know the transport properties of these topological metals, high purity samples as well as very low temperature will be needed because of the contribution from bulk states or impurity effects. In a recent report, it was also shown that an intriguing coupling between the surface and bulk states will occur [5]. A simple solution to this bothersome problem is to prepare a topological metal on an ultrathin film, in which the surface-to-bulk ratio is drastically increased. Therefore in the present study, we have investigated if there is a method to make an ultrathin Bi1-xSbx film on a semiconductor substrate. From reflection high-energy electron diffraction observation, it was found that single crystal Bi1-xSbx films (0${\sim}30\;{\AA}A$ can be prepared on Si(111)-$7{\times}7$. The transport properties of such films were characterized by in situ monolithic micro four-point probes [6]. The temperature dependence of the resistivity for the x=0.1 samples was insulating when the film thickness was $240\;{\AA}A$. However, it became metallic as the thickness was reduced down to $30\;{\AA}A$, indicating surface-state dominant electrical conduction. Figure 1 shows the Fermi surface of $40\;{\AA}A$ thick Bi0.92Sb0.08 (a) and Bi0.84Sb0.16 (b) films mapped by angle-resolved photoemission spectroscopy. The basic features of the electronic structure of these surface states were shown to be the same as those found on bulk surfaces, meaning that topological metals can be prepared at the surface of an ultrathin film. The details will be given in the presentation.

• Korean Journal of Materials Research
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• v.6 no.8
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• pp.761-767
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• 1996

The composite fiber adsorbents containing amidoxime group were prepared and separation properties of uranium ion from seawater were investigated. The amount of uranium adsorption was increased with an increase in adsorption time. When the mole ratio of monomer and comonomer, such as acrylonitrile (AN), tetraethyleneglycol dimethacrylate(TEGMA), and divinylbenzene (DVB), were 1 :0. 1 :0.003, this resin showed the maximum adsorption ability for uranium at a level of pH 8. The amount of uranium adsorption was also increased linearly to one hour with an increase in the content of adsorbent which was added in the composite fiber adsorbents(CFA). The maximum adsorption for uranium of CF A showed at $25^{\circ}C$. Hence, the adsorption ability of CF A for calcium and magnecium ions were increased gradually by the recycling of adsorption and disorption, the adsorption content of their on were 0.3, 0.9mmole/g-adsorbents, respectly. It also showed that the adsorption contents of Ca and \1g ions were much lower than them of uranium. The desorption of uranium on the CF A was carried out , bout 100% within 30min, and the desorption rate of various CF A were equalled.