• Microbiology and Biotechnology Letters
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• v.16 no.5
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• pp.369-373
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• 1988

The gene for thermostable alpha-amylase from the thermostable bacterium Bacillus licheniformis has been cloned and expressed in Escherichia coli. The Alpha-amylase producing E. coli cells contained a 7.4 kb chimeric plasmid (pTA 322) which was composed of the vector pBR322 and a 3.1 kb EcoRI fragment of B. licheniformis DNA. The alpha-amylase from cloned fragement was shown to be indistlnguishable from that of B. licheniformis in the optimum temperature of 9$0^{\circ}C$, heat stability and the pH stability. The foreign gene was expressed efficiently in E. coli and stably maintained.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1439-1447
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• 2023

The fuel cycle characteristics of the IVG.1M reactor were studied within the framework of the research reactor conversion program to modernize the IVG.1M reactor. Optimum use of the nuclear fuel and reactor was achieved through routine methods which included partial fuel reloading combined with scheduled maintenance operations. Since, the additional problem in planning the fuel cycle of the IVG.1M reactor was the poisoning of the beryllium parts of the core, reflector, and control system. An assessment of the residual power and composition of spent fuel is necessary for the selection and justification of the technology for its subsequent management. Computational studies were performed using the MCNP6.1 program and the neutronics model of the IVG.1M reactor. The proposed scheme of annual partial fuel reloading allows for maintaining a high reactor reactivity margin, stabilizing it within 2-4 β_eff for 20 years, and achieving a burnup of 9.9-10.8 MW × day/kg U in the steady state mode of fuel reloading. Spent fuel immediately after unloading from the reactor can be placed in a transport packaging cask for shipping or safely stored in dry storage at the research reactor site.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.11
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• pp.997-1006
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• 2009

Organic removal efficiency and methane production rate, a feasibility of power generation from biogas, and the optimum conditions for membrane operation were evaluated for the pilot scale (5 tons/day) two-phase anaerobic digestion coupled with ultra filtration (TPADUF) system fed with garbage leachate. The TPADUF system is consisted of a thermophilic acidogenic reactor, a mesophilic methanogenic reactor, and an UF membrane. When garbage leachate with 150 g/L of TCOD was fed to the TPADUF up to organic loading rate (OLR) of 11.1 g COD/L/d, the effluent TCOD was lower than 6 g/L and the average removal efficiencies of TCOD and SCOD were higher than 95%. The methane composition of the gas was 65%, and the methane yield was 39 $m^3/m^3$ garbage leachatefed, 260 $m^3$/tons $COD_{added}$, or 270 $m^3$/tons $COD_{removed}$, even there was some gas leak. The power production per consumed gas was 0.96 kWh/$m^3$ gas or 1.49 kWh/$m^3$ methane. This lower power production efficiency mainly due to the small capacity of gas engine (15 kW class). The membrane was operated at the average flux of 10 L/$m^2$/hr. When the flux decreased, washing with water and chemical (NaOCl) was conducted to restore the flux. In the TPADUF system, optimum pH could be maintained without alkali addition by recycling the membrane concentrate or mixed liquor of the methanogenic digester to the acidogenic reactor. Also, partial production of methane in the acidogenic reactor had a positive effect on lowering the OLR of the methanogenic reactor.

• Journal of the Korean Society of Radiology
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• v.9 no.6
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• pp.393-401
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• 2015

Radiation therapy for lung cancer is an effective treatment during monotherapy or combination therapy. Studies have reported that the optimum utilization rate of radiation therapy is estimated at 61% to 74%. Radiation therapy in Korea has been investigated to be low; further studies are needed. This study was intended to assess the appropriateness of the use of radiation and to reveal the use of radiation therapy-related factors by examining radiation therapy in lung cancer patients of Busan and South Gyeongnam Province. This study was aimed at the population diagnosed with lung cancer in Busan and South Gyeongnam Province. To conduct the study, 1036 patients enrolled in two hospitals were collected and 897 appropriate as subjects were selected. We compared the optimum utilization rate and actual rate of radiation therapy, and revealed the adequacy and related factors for use of radiotherapy. Of 897 patients, 503 (56%) were treated with medical therapy and 394 (44%) were given radiotherapy. The radiotherapy utilization rate of all lung cancer patients was 42%. The proportion of non-small cell lung cancer by histologic type was 33% and that of small cell lung cancer was 90%. Factors related to radiation therapy used in cancer were age, histological type, clinical stage, doctor refereed to, and clinical examination. Compared to radiation utilization by region (site), curative chest therapy was 42%; palliative treatment was 26%. In the comparison of histologic types, utilization of small-cell lung cancer is lower; the lowest especially in the stage III. Utilization of radiation therapy in Busan and South Gyeongnam Province was lower than the reasonable one. Utilization difference could be explained by patient factors, tumor factors, and health service factors. To improve utilization,development ofoutreach service programs and activation of the multidisciplinary team are required.

• Journal of the Korea Concrete Institute
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• v.25 no.3
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• pp.339-345
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• 2013

This study is to derive from the required performances and the optimum mix proportion of the roof concrete placed in the in-ground LNG storage tank with a capacity of 200000 $m^3$, and propose the actual data for site concrete work. The concrete placing work without sliding and segregation in the fresh concrete condition is very important because the slope of domed roof is varied in the large range by its curvature. Also the control of hydration heat and the strength development at test ages are classified with massive section about 1.4 m thick and considered to the pre-stressing work and removal of air support after concrete placing work. Considering above condition, slump range is selected $100{\pm}25$ mm under the slope $20^{\circ}$ and $150{\pm}25$ mm over the slope $20^{\circ}$ s until 60 minutes of elapsed time. Also, the roof concrete is satisfied with compressive strength range including design strength at 91 days (30 MPa), pre-stressing work at 7 days (10 MPa), air support removal work at 21 days (14 MPa). Replacement ratio of limestone powder is determined by confined water ratio test and main design factors include water-cement ratio (W/C), sand-aggregate ratio and dosage of admixture. As test results, the optimum mix proportion of the roof concrete used low heat cement is as followings. 1) Replacement ratio of limestone powder 25% by confined water ratio test 2) Water-cement ratio 57.8% 3) Sand-aggregate ratio 42.0%. Also, test results for the adiabatic temperature rising test is satisfied with its criteria and shown the lower value compared to preceding storage tank (TK-13, 14). These required performances and the optimum mix proportion is to apply the actual construction work.

• Journal of Korean Society of Forest Science
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• v.101 no.3
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• pp.387-394
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• 2012

The study was conducted to develop an effective forest resources use models for an alternate use of abandoned quarry by an attitude survey. According to the result of survey, a pessimistic view due to dust, noise pollution, and forest damage was 5% higher than an affirmative view by economic benefits from the development of quarry. The 42% of the respondents preferred the alternate use of abandoned quarry and the 25% of the respondents wanted an art and cultural space. The optimum size of alternate use was 5-10 ha (43%) with the requirement of nearby residents (32%). According to the SWOT analysis for abandoned quarry, the strength factors were an effective use of land, the content development of modern industrial inheritance + cultural and art fusion, attraction for nearby city and visitors, a harmony of beauty landscape and clean environment, and a sustainable increase of domestic and foreign visitors with the 5-day-work week. The opportunity factors were the improvement of traffic networks through KTX and local highway, the creation of the new growth engines with the establishment of artistic creation belts, the providing of unique cultural and art space through grafting of tour and education, the creation of local income through stone processed goods, and the vitalization of local development through eco-city. The weakness factors were a psychological remoteness and backwardness, and the weakness of staying tour infra. The threat factors were a poor financial support for sustainable development in nearby quarry and a modify of legal and institutional system for the alternated use of abandoned quarry. The developed restoration models for the alternate use in abandoned quarry are classified to a sculpture park, a waterfall and lake park, a rock-climbing, a sports park + forest park, a native botanical garden, a culture and art park, a complex park, a water storage site, a water storage site to extinguish forest fire, a geriatric hospital, an agricultural facility, and a school site types etc. The results suggest that the alternate use in the abandoned soil and stone quarry is needed to establish facility use models with consideration of user's preference.

• Journal of the Korean Institute of Gas
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• v.24 no.2
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• pp.1-8
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• 2020

Centrifugal pump is a facility that transfers energy to fluid through centrifugal force, which is usually generated by rotating the impeller at high speed, and is a major process facility used in many LNG production bases such as vaporization seawater pump, industrial water and fire extinguishing pump using seawater. to be. Currently, pumps in LNG plant sites are subject to operating conditions that vary depending on the amount of supply desired by the customer for a long period of time. Pumps in particular occupy a large part of the consumption strategy at the plant site, and if the optimum operation condition is not available, it can incur enormous energy loss in long term plant operation. In order to solve this problem, it is necessary to identify the performance deterioration factor through the flow analysis and the result analysis according to the fluctuations of the pump's operating conditions and to determine the optimal operation efficiency. In order to evaluate operation efficiency through experimental techniques, considerable time and cost are incurred, such as on-site operating conditions and manufacturing of experimental equipment. If the performance of the pump is not suitable for the site, and the performance of the pump needs to be reduced, a method of changing the rotation speed or using a special liquid containing high viscosity or solids is used. Especially, in order to prevent disruptions in the operation of LNG production bases, a technology is required to satisfy the required performance conditions by processing the existing impeller of the pump within a short time. Therefore, in this study, the rotation difference of the pump was applied to the ANSYS CFX program by applying the modified 3D modeling shape. In addition, the results obtained from the flow analysis and the curve fitting toolbox of the MATLAB program were analyzed numerically to verify the outer diameter correction theory.

• Current Research on Agriculture and Life Sciences
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• v.19
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• pp.45-54
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• 2001

This study was carried out to provide fundamental data for prospective forest-road project and forest-road network arrangement through appraising existing forest-road network with density, extension distance, maximum yarding distance and yarding area, position of forest-road line considered above foundation of two theories, one is "theory of optimal forest-road density" which has expense for yarding cost and constructing forest-road minimized, the other is "theory of optimal forest-road arrangement" which has investment effect maximized. The results are as follows. 1. In density and extension distance of the forest-road by site, it was showed up that density of existing forest-road is lower than that of calculated forest-road. So, it is thought that some additional forest-roads have to be constructed. 2. In the arrangement of the forest-road network by site, it was showed up that the arrangement of calculated forest-road is higher than that of existing forest-road arrangement for the forestry and yarding function. So, it is thought that the arrangement of forest-road network have to be considered to maximize the investment effect. 3. In "mean maximum distance for yarding" and "mean area which yarding can be done" by horizontal and inclined distance, the existing forest-road networks were different from those of calculated forest-road network. So, calculated forest-road network making investment effect maximize is more effective than existing forest-road network. Hence, in prospective forest-road project, it is needed that forest-road network having "area which yarding can be done" maximized through considering function for yarding have to be constructed.

• Journal of Biosystems Engineering
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• v.30 no.1 s.108
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• pp.45-55
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• 2005

Knowledge of the relationship between crop yield and yield-limiting factors is essential for precision farming. However, developing this knowledge is not easy because these yield-limiting factors are interrelated and affect crop yield in different ways. In this study, data for grain yield and yield-limiting factors, including crop chlorophyll content, soil chemical properties, and topography were collected for a small (0.3 ha) rice paddy field in Korea and a large (36 ha) upland corn field in the USA, and relationships were investigated with path analysis. Using this approach, the effects of limiting factors on crop yield could be separated into direct effects and indirect effects acting through other factors. Path analysis provided more insight into these complex relationships than did simple correlation or multiple linear regression analysis. Results of correlation analysis for the rice paddy field showed that EC, Ca, and $SiO_2$ had significant (P<0.1) correlations with rice yield, while pH, Ca, Mg, Na, $SiO_2,\;and\;P_2O_5$ had significant correlations with the SPAD chlorophyll reading. Path analysis provided additional information about the importance and contribution paths of soil variables to rice yield and growth. Ca had the highest direct effect (0.52) and indirect effect via Mg (-0.37) on rice yield. The indirect effect of Mg through Ca (0.51) was higher than the direct effect (-0.38). Path analysis also enabled more appropriate selection of important factors limiting crop yield by considering cause-and-effect relationships among predictor and response variables. For example, although pH showed a positive correlation (r=0.35) with SPAD readings, the correlation was mainly due to the indirect positive effects acting through Mg and $SiO_2$, while pH not only showed negative direct effects, but also negatively impacted indirect effects of other variables on SPAD readings. For the large upland Missouri corn field, two topographic factors, elevation and slope, had significant (P<0.1) direct effects on yield and highly significant (P<0.01) correlations with other limiting factors. Based on the correlation analysis alone, P and K were determined to be nutrients that would increase corn yield for this field. With the help of path analysis, however, increases in Mg could also be expected to increase corn yield in this case. In general, path analysis results were consistent with published optimum ranges of nutrients for rice and com production. We conclude that path analysis can be a useful tool to investigate interrelationships between crop yield and yield limiting factors on a site-specific basis.

• Journal of Life Science
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• v.22 no.4
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• pp.437-446
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• 2012

A metagenomic library of cow rumen in the pCC1FOS phage vector was screened in $E.$ $coli$ EPI300 for cellulase activity on carboxymethyl cellulose agar plates. One clone was partially digested with $Sau$3AI, ligated into the $Bam$HI site of the pBluescript II SK+ vector, and transformed into $E.$ $coli$ $DH5{\alpha}$. We obtained a 1.5 kb insert DNA, designated $cel$5C, which hydrolyzes carboxymethyl cellulose. The cel5C gene has an open reading frame (ORF) of 1,125 bp encoding 374 amino acids. It belongs to the glycosyl hydrolase family 5 with the conserved domain LIMEGFNEIN. The molecular mass of the Cel5C protein induced from $E.$ $coli$ $DH5{\alpha}$, as analyzed by CMC SDS-PAGE, appeared to be approximately 42 kDa. The enzyme showed optimum cellulase activity at pH 4.0, and $50^{\circ}C$. We examined whether the $cel$5C gene comes from the 49 identified cow rumen bacteria using PCR. No PCR bands were identified, suggesting that the $cel$5C gene came from the unidentified cow rumen bacteria.