• Journal of the Korea Safety Management & Science
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• v.14 no.1
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• pp.117-122
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• 2012

This paper deals with the productivity increment through construction of lean production system for automobile factory in China. This lean production system has been progressed according to 5 steps. Step 1 is the work preparation. Step 2 is the process design. Step 3 is the establishment of method to count production quantity. Step 4 is the establishment of measuring method for input and output. Finally, step 5 is the construction of flexible production system able to adapt for environment change. This lean production system is expected to obtain the productivity increment by 50% for plastic plant and reduction by 50% in inventory quantity.

• Journal of the Korean Solar Energy Society
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• v.34 no.6
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• pp.11-18
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• 2014

Two-step water splitting thermochemical cycle with $CeO_2$ foam device was investigated by using a solar simulator composed of 2.5 kW Xe-Arc lamp and mirror reflector. The hydrogen production of $CeO_2$ foam device depending on reaction temperature of Thermal-Reduction step and Water-Decomposition step was analyzed, and the hydrogen production of $CeO_2$ and $NiFe_2O_4/ZrO_2$ foam devices was compared. As a result, the amount of reduced $CeO_2$ considerably varies according to the reaction temperature of Thermal-Reduction step. and hydrogen production was not much when the amount of reduced $CeO_2$ decreased even if the reaction temperature of Water-Decomposition step was high. Therefore, it is very important to keep the reaction temperature of Thermal-Reduction step high in two-step thermochemical cycle with $CeO_2$.

• Journal of the Korean Solar Energy Society
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• v.37 no.5
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• pp.27-37
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• 2017

In this study, an artificial solar simulator composed of a 2.5 kW Xe-Arc lamp and mirror reflector was used to carry out the solar thermal two step thermochemical water decomposition cycle which can produce high efficiency continuous hydrogen production. Through various operating conditions, the change of hydrogen production due to the possibility of a dual-zone reactor and heat recovery were experimentally analyzed. Based on the reaction temperature of Thermal-Reduction step and Water-Decomposition step at $1,400^{\circ}C$ and $1,000^{\circ}C$ respectively, the hydrogen production decreased by 23.2% under the power off condition, and as a result of experiments using heat recovery technology, the hydrogen production increased by 33.8%. Therefore, when a thermochemical two-step water decomposition cycle is conducted using a dual-zone reactor with heat recovery, it is expected that the cycle can be operated twice over a certain period of time and the hydrogen production amount is increased by at least 53.5% compared to a single reactor.

• Toxicological Research
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• v.16 no.4
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• pp.317-323
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• 2000

The immunosuppressive effects of thirty nine chemicals chosen by their potential toxicity were evaluated using a three-step testing method. The immunotoxicity test method developed in this study consisted of three simple assays of lymphoproliferation, mixed leukocyte response, and interleukin (IL)-2 production. The first step was mitogen-induced proliferation assay. Ten chemicals showed the inhibitory effects on the mitogen (lipopolysaccharide or concanavalin A)-induced proliferation in dose-dependent manners. The second step was mixed lymphocyte response. This step crosschecked the growth-suppressive effects detected at the first step. All of 10 chemicals, which showed suppression of lymphoproliferation, also exhibited the suppressive effects on the mixed lymphocyte response in the similar range of chemical concentration. The third step was planned to determine whether or not this growth suppression was mediated through an early activation of T-cell, which could be represented with IL-2 production. Six out of 10 chemicals decreased the interleukin-2 production in the similar concentration range used in the step 1 and 2. These results suggest that those 6 chemicals might have their targets on the signal transduction path-way toward the IL-2 production. In the meantime the other 4 chemicals might have their targets after the IL-2 production signal. Taken all together, the three-step test would be simple, fast, and efficient to deter-mine whether or not the chemical has immunosuppressive effects.

• The Journal of Fisheries Business Administration
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• v.42 no.2
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• pp.113-130
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• 2011

The laver has been cultivated long time ago by Korea and Japan. Korean Laver Industry has been influenced by Japan on the many factors since 20th. Nevertheless now the both country showed widening disparities across the aspect of total Laver Industry each other. The development steps of Korea and Japan Laver Industry have been advanced differently. That is, we can keep the Laver Industry development steps of both countries separate by 4 steps. But insignificant of every step against both countries has been dissimilar. We can separate from 4 steps in Korea, 1 step is origin period from beginning of laver cultivation to 1961. Next step is First Development period from 1962 to 1978. This period come out production increase from about 10,000 tons early 1960 to 50,000 tons late 1970. Next step is Second Development period from 1979 to 2000. This period come out eminent production increase from about 50,000 tons early 1980 to 200,000 tons late 1990. Next step is Stabilization period from 2001 to now. This period come out production control the size of its production and enlargement of Laver Export. We can also separate from 4 steps in Japan, 1 step is origin period from beginning of laver cultivation to 1944. Next step is Development period from 1945 to 1975. This period come out production increase from about 4 billion sheets early 1960 to 8.5 billion sheets 1975. Next step is Peak period from 1976 to 1982. This period come out sustainable production peak by 6~8 billion sheets and high price. Next step is Decline period from 1983 to now. This period come out production control the size of its production and sustainable price down. These differences showed out facing problems of Korean and Japanese Laver Industry differently. In case of Korea, the facing problems show out 3. First is structural problem, for example, trouble between original laver producer and the finished producer by dry laver products. Second is Insufficiency of Plants Protection System. Third is low quality of Laver. In case of Japan, the facing problems also show out 3. First is sustainable decrease of laver consumption. Second is change of mind against laver, for example, the change of the propensity to consume, and decrease of brand power. Third is Influence of global system. The difference of development steps of Korea and Japan Laver Industry show out 2 point of view to us. First we need consider positive strategy against laver production system of enlargement. Second, we need consider separate strategy against high quality laver and low quality laver.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.4
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• pp.322-330
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• 2008

This paper deals with an economic evaluation of domestic photobiological hydrogen production. We evaluate the economic feasibility of domestic photobiological hydrogen production utilizing green algae and cyanobacteria. In addition, we make some sensitivity analysis of hydrogen production prices by changing the values of input factors such as the price of a photo-bioreactor and the value of solar to hydrogen efficiency. The estimated hydrogen production price of the two-step indirect biophotolysis was 12,099won/kg$H_2$. It is expected that the hydrogen production price by the two-step indirect biophotolysis can be reduced to 2,143won/kg$H_2$ if the solar to hydrogen efficiency is increased to 10% and the price of a photo-bioreactor is decreased to $25/$m^2$. The two-step indirect biophotolysis is evaluated as uneconomical at this time, and we need to enhance the solar to hydrogen efficiency and to reduce the prices of the photo-bioreactor and system facilities.

• Journal of Microbiology and Biotechnology
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• v.23 no.10
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• pp.1434-1444
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• 2013

We established a two-step production process using immobilized S. cerevisiae and P. stipitis yeast to produce ethanol from seaweed (U. pertusa Kjellman) hydrolysate. The process was designed to completely consume both glucose and xylose. In particular, the yeasts were immobilized using DEAE-corncob and DEAE-cotton, respectively. The first step of the process included a continuous column reactor using immobilized S. cerevisiae, and the second step included a repeated-batch reactor using immobilized P. stipitis. It was verified that the glucose and xylose in 20 L of medium containing the U. pertusa Kjellman hydrolysate was converted completely to about 5.0 g/l ethanol through the two-step process, in which the overall ethanol yield from total reducing sugar was 0.37 and the volumetric ethanol productivity was 0.126 g/l/h. The volumetric ethanol productivity of the two-step process was about 2.7 times greater than that when P. stipitis was used alone for ethanol production from U. pertusa Kjellman hydrolysate. In addition, the overall ethanol yield from glucose and xylose was superior to that when P. stipitis was used alone for ethanol production. This two-step process will not only contribute to the development of an integrated process for ethanol production from glucose-and xylose-containing biomass hydrolysates, but could also be used as an alternative method for ethanol production.

• Journal of the Korean Solar Energy Society
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• v.33 no.3
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• pp.42-50
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• 2013

Solar thermal reactor was studied for hydrogen production with a two step thermochemical cycle including T-R(Thermal Reduction) step and W-D(Water Decomposition) step. NiFe2O4 and Fe3O4 supported by monoclinic ZrO2 were used as a catalyst device and Ni powder was used for decreasing the T-R step reaction temperature. Maintaining a temperature level of about $1100^{\circ}C$ and $1400^{\circ}C$, for 2-step thermochemical reaction, is important for obtaining maximum performance of hydrogen production. The controller was designed for adjusting high temperature solar thermal energy heating the foam-device coated with nickel- ferrite powder. A Pill temperature control system was designed based on 2-step thermochemical reaction experiment data(measured concentrated solar radiation and the temperature of foam device during experiment). The cycle repeated 5 times, ferrite conversion rate are 4.49~29.97% and hydrogen production rate is 0.19~1.54mmol/g-ferrite. A temperature controller was designed for increasing the number of reaction cycles related with the amount of produced hydrogen.

• Journal of the Korean Solar Energy Society
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• v.37 no.2
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• pp.13-22
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• 2017

Two-step water splitting thermochemical cycle with $CeO_2/ZrO_2$ foam device was investigated by using a solar simulator composed of 2.5 kW Xe-Arc lamp and mirror reflector. The hydrogen production of $CeO_2/ZrO_2$ foam device depending on heat recovery of Thermal-Reduction step and Water-Decomposition step was analyzed, and the hydrogen production of $CeO_2/ZrO_2$ and $NiFe_2O_4/ZrO_2$ foam devices was compared. Resultantly, the quantity of hydrogen generation increased by 52.02% when the carrier gas of Thermal-Reduction step is preheated to $200^{\circ}C$ and, when the $N_2/steam$ is preheated to $200^{\circ}C$ in the Water-Decomposition step, the quantity of hydrogen generation increased by 35.85%. Therefore, it is important to retrieve the heat from the highly heated gases discharged from each of the reaction spaces in order to increase the reaction temperature of each of the stages and thereby increasing the quantity of hydrogen generated through this.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.5
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• pp.691-697
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• 2011

In this study, by using the Water footprint technique, the water consumption by washing machines, which holds higher ranks in using water than any other electric appliances, was analyzed during their life cycle. The life cycle is defined as raw materials production step, manufacturing step, and using step. In raw materials production step, Input materials were researched by using LCI DB(Life Cycle Inventory Database) and the water consumption was calculated with consideration of approximately 65% Input materials which were based weight. In manufacturing step, the water consumption was calculated by the amount of energy used in assembly factories and components subcontractors and emission factor of energy. In using step, referring to guidelines on carbon footprint labeling, the life cycle is applied as 5 years for a washing machine and 218 cycles for annual bounds of usage. The water and power consumption for operating was calculated by referring to posted materials on the manufacture's websites. The water consumption by nation unit was calculated with the result of water consumption by a unit of washing machine. As a result, it shows that water consumption per life cycle s 110,105 kg/unit. The water consumption of each step is 90,495 kg/unit for using, 18,603 kg for raw materials production and 1,006 kg/unit for manufacturing, which apparently shows that the using step consume the most water resource. The water consumption by nation unit is 371,269,584tons in total based on 2006, 83,385,649 tons in both steps of raw material production and manufacturing, and 287,883,935 tons in using step.