• Journal of Plant Biotechnology
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• 제4권4호
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• pp.163-170
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• 2002

Radiation induced and somaclonal variations were investigated in the regenerates from gamma irradiated and controlled embryogenic callus (EC) of sweetpotato cvs., Yulmi and White Star by morphological, RAPD and AFLP analysis. Most (approx. 90%) of the EC produced somatic embryos developed into plantlets after being transferred to the auxin-free medium. The frequency of morphological variants derived from the irradiated callus ranged from 3 to 7.8% compared to 0.1-1.1% of that derived from the non-irradiated. Morphological variants were selected from the regenerates and analyzed by RAPD and AFLP procedures. RAPD polymorphisms of Yulmi and White Star regenerates from irradiated calli were 8.8% and 6.1%, respectively. However, the polymerphisms among regenerates from the non-irradiation treatment in these two cultivars were non-detectable and 3%, respectively. AFLP polymorphisms of Yulmi and White Star regenerates from irradiated calli were 29.9% and 28.6%, respectively. while the frequencies for those form non-irradiated calli were 8.5% and 5.6%, respectively. Both the control plants and variants from the nonirradiated were clustered together, while variants from irradiated were separated from the group by Nearest-Neighbor-Interchange Branch Swapping Abbreviation: EC (Embryogenic callus), AFLP (Amplified Fragment Length Polymorphism), RAPD (Random amplified polymorphic DNA)

• Journal of Multimedia Information System
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• 제3권3호
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• pp.63-68
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• 2016

Environmental downtime produces a significant cost to organizations and makes them unable to do business because what happens in the data center affects everyone. In addition, the amount of electrical energy consumed by data centers increases with the amount of computing power installed. Installation of physical Information Technology and facilities related to environmental concerns, such as monitoring temperature, humidity, power, flood, smoke, air flow, and room entry, is the most proactive way to reduce the unnecessary costs of expensive hardware replacement or unplanned downtime and decrease energy consumed by servers. In this paper, we present remote system for monitoring datacenter implementing using open-source hardware platforms; Arduino, Raspberry Pi, and the Gobetwino. The sensed data displayed through Arduino are transferred using Gobetwino to the nearest host server such as temperature, humidity and distance every time an object hitting another object or a person coming in entrance. The raspberry Pi records the sensed data at the remote location. The objective of collecting temperature and humidity data allows monitoring of the server's health and getting alerts if things start to go wrong. When the temperature hits $50^{\circ}C$, the supervisor at remote headquarters would get a SMS, and then they would take appropriate actions to reduce electrical costs and preserve functionality of servers in data centers.

• Journal of Microbiology and Biotechnology
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• 제23권10호
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• pp.1460-1471
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• 2013

Microalgal biofuel production from wastewater has economic and environmental advantages. This article investigates the lipid production from high chemical oxygen demand (COD) bioethanol wastewater without dilution or additional nutrients, using a newly isolated heterotrophic microalga, Chlorella vulgaris LAM-Q. To enhance lipid accumulation, the combined effects of important operational parameters were studied via response surface methodology. The optimal conditions were found to be temperature of $22.8^{\circ}C$, initial pH of 6.7, and inoculum density of $1.2{\times}10^8cells/ml$. Under these conditions, the lipid productivity reached 195.96 mg/l/d, which was markedly higher than previously reported values in similar systems. According to the fatty acid composition, the obtained lipids were suitable feedstock for biodiesel production. Meanwhile, 61.40% of COD, 51.24% of total nitrogen, and 58.76% of total phosphorus were removed from the bioethanol wastewater during microalgal growth. In addition, 19.17% of the energy contained in the wastewater was transferred to the microalgal biomass in the fermentation process. These findings suggest that C. vulgaris LAM-Q can efficiently produce lipids from high-concentration bioethanol wastewater, and simultaneously performs wastewater treatment.

• Proceedings of the KIPE Conference
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.537-541
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• 2004

A high efficiency ZVS PWM asymmetrical half bridge converter for a plasma display panel (PDP) sustaining power module is proposed in this paper. To achieve the ZVS of power switches for the wide fond range, n small additional inductor $L_{lkg}$, which also acts as an output filter inductor, is serially inserted to the transformer primary side. Then, to solve the problem related to ringing in the secondary rectifier caused by $L_{lkg}$, the proposed circuit employs a structure without the output filter inductor, which helps the voltages across rectifier diodes to be clamped at the output voltage. Therefore, no dissipative RC (resistor capacitor) snubber for rectifier diodes is needed and n high efficiency as well as low noise output voltage can be realized. In addition, since it has no large output inductor filter, it features a simpler structure, lower cost, less mass, and lighter weight. Moreover, since all energy stored in $L_{lkg}$ is transferred to the output side, the circulating energy problem can be effectively solved. The operational principle, theoretical analysis, and design considerations are presented. To confirm the operation, validity, and features of the proposed circuit, experimental results from a 425W, 385Vdc/170Vdc prototype are presented.

• Proceedings of the KIPE Conference
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.341-345
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• 2004

A high efficiency and low device stress voltage and current clamping BVS PWM asymmetrical half bridge converter is proposed in this paper. To achieve the ZVS of power switches along the wide load range, the transformer leakage inductor $L_{Ikg}$ is increased. Then, to solve the problem related to ringing in the secondary rectifier caused by the resonance between $L_{Ikg}$ and rectifier junction capacitors, the proposed converter employs a voltage and current clamping cell, which helps voltages and currents of rectifier diodes to be clamped at the output voltage and output current, respectively. Therefore, no RC-snubber for rectifier diodes is needed and a high efficiency as well as low noise output voltage can be realized. In addition, since all energy stored in $L_{Ikg}$ is transferred to the output side, the circulating energy problem can be effectively solved and duty loss does net exist. The operational principle, theoretical analysis, and design considerations are presented. To confirm the operation, validity, and features of the proposed circuit, experimental results from a 425W, 385-170Vdc prototype are presented.

• Nuclear Engineering and Technology
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• 제2권1호
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• pp.19-25
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• 1970

A study was conducted on the coolant mixing between water flowing in two adjacent subchannels. Measurements were made of the quantity of mass transferred between a larger rectangular channel and a smaller triangular channel in a 19-rod fuel bundle under the conditions of single phase flow and air-water two-phase flow. The results of the experiments showed that the low mixing rate appears in single phase flow, and high mixing rate was measured in air-water two-phase flow Mixing rate decreases with the increasing of air void fraction during the air-water flow. It seems that the high mixing rate in the air-water flow was caused due to adequate agitation of the chaotic air void.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제28권1호
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• pp.42-47
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• 2016

Adjacent housing units suffer inevitable thermal losses if an unheated unit exists in an apartment building. Thermal loss of the units adjoining the unheated apartment can be neglected because the contact area is small and insulators are located in the walls. When insulators are not included in the slab between the upper and lower units, 70% of the heat supplied by an Ondol system may be used in the original unit, but 30% is transferred to the unit on the lower floor. Another 30% can be obtained from the ceiling if the upper floor housing unit is heated. This strong thermal connection is a characteristic of Ondol heating in apartment buildings. When there is an unheated unit, the lower floor unit uses 42.3% more heating energy if there is no insulation and 19.5% if a 35 mm insulator is used as in the current guidelines. Therefore, much thicker insulation should be applied to weaken the thermal connection.

• Journal of Korea Foresty Energy
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• 제20권2호
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• pp.20-27
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• 2001

An effective method for production of glucose was developed using enzymatic hydrolysis of Suwon poplar by the cellulase. Enzymatic hydrolysis of wood is the reaction to produce glucose from wood using enzyme which derives from microorganism. Glucose can be transferred easily to ethanol by fermentation. Ethanol is the starting material for producing acetone, butanol, citric acid and lactic acid. The mechanism of the enzymatic hydrolysis of cellulose are reasonably explained in terms of the sequential action of three different types of enzymes, endo-cellulase, ex-cellulase, and $\beta$ -glucosidase. The goal of this work was to investigate the cellulose hydrolysis pretreated polar with various concentration NaOH, the crystallinity of cellulose, lignin contents and the degree of hydrolysis.

• The Bulletin of The Korean Astronomical Society
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• 제37권1호
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• pp.93.2-93.2
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• 2012

Point Spread Function (PSF) is one of the most important optical characteristics for describing the performance of a telescope. And a concept of subpixelization is inevitable in evaluating the undersampled PSF (Shin and Sakurai 2009). Then, the internal structure of Yohkoh SXT CCD pixel is not uniform: For the top half of pixel area, the X-ray should pass a so-called gate structure where the charges are transferred to an output amplifier. This gate structure shows energy-dependent sensitivity (Tsuneta et al. 1991). For example, for Al-K (8.34 A) X-ray emission, the transmission of the polysilicon gate is about 0.9. Also, for the peak coronal response of the SXT thin filters, around 17 angstrom (0.729 keV), the transmission of the gate is about 0.6, falling off sharply towards longer wavelengths. It should be noted that this spectrally dependent non-uniform response of each CCD pixel will certainly have a noticeable effect on the properties of the PSF at longer wavelengths. Therefore, especially for analyzing the undersampled PSF of low energy source, a careful consideration of non-uniform internal pixel structure is required in determining the shape of the PSF core. The details on the effect of gate structure will be introduced in our presentation.

• Proceedings of the KSME Conference
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• 대한기계학회 2002년도 학술대회지
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• pp.403-406
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• 2002

A number of the experiments on the phenomenon in which the thermal energy was transferred from a hot sphere to the surrounding water through the film boiling process had been conducted. As the sphere only carried the thermal energy associated with its initially high temperature but did not contain any other thermal source, the film boiling was only driven by the decreasing temperature of the sphere and, thus, was time dependent. The results from the experiments showed that the temperature of the sphere was slowly decreased in the beginning. This corresponded to the period in which the sphere was penetrating the water surface. Later, when the sphere was fully submerged and the transition film boiling was observed over the whole surface, the temperature of the sphere was decreased relatively much faster. In the last stage, the temperature of the sphere was again slowly decreased. This was considered caused by the relatively low temperature of the sphere, which reduced and later ceased the film boiling process. In addition, the estimation of the departure rate of the steam bubbles from the film layer was also correlated for the experiments.