• KSBB Journal
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• v.4 no.2
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• pp.69-73
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• 1989

Batch fermentation runs were made with initial xylose concentrations of 2%, 4%, 8%, and 10%. The maximum yields were 0.46, 0.45, 0.43, and 0.42g ethanol/g xylose for 2%, 4%, 8%, and 10% xylose respectively. Xylitol formation was insignificant over a wide range of sepcific oxygen supply rates and xylose concentrations. The maximum specific productivities were 0.110, 0.110, 0.241, and 0.0961g ethanol/hr-g DCW for 2% through 10% xylose concentration.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.6
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• pp.1-9
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• 2004

For improvement of productivity and cutting tool lift, cutting force in end milling needs to be predicted accurately. In order to analyze cutting force, the cutting dynamics was modelled mathematically by using chip load, cutting geometry, and the relationship between cutting forces and the chip load. Specific cutting force coefficients of the cutting dynamics model were obtained by average cutting forces, tool diameter, cutting speed, fled, axial depth and radial depth of cut. The effects of the cutting conditions on the specific cutting force constants in milling were studied. The model is verified through comparisons of model predicted cutting forces with measured cutting forces obtained from machining experiments.

• The Microorganisms and Industry
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• v.19 no.2
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• pp.34-41
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• 1993

Industrial strain improvement is concerned with developing or modifying microorganisms used in production of commercially important fermentation products. The aim is to reduce the production cost by improving productivity of a strain and manipulating specific characteristics such as the ability to utilize cheaper raw materials or resist bacteriophages. The traditional empirical approach to strain improvement is mutation combined with selection and breeding techniques. It is still used by us to improve the productivity of organisms in amino acids, organic acids and enzymes production. The breeding of high L-lysine-producing strain Au112 is one of the outstanding examples of this approach. It is a homoserine auxotroph with AEC, TA double metabolic analogue resistant markers. The yield reaches 100 g/l. Besides, the citric acid-producing organism Aspergillus niger, Co827, its productivity reaches the advanced level in the world, is also the result of a series mutations especially with $^60Co{\gamma}$-radiation. The thermostable .alpha.-amylase producing strain A 4041 is the third example. By combining physical and chemical mutations, the strain A 4041 becomes an asporogenous, catabolite derepressed mutant with rifamycin resistant and methionine, arginine auxotroph markers. The .alpha.-amylase activity reaches 200 units/ml. The fourth successful example of mutation in strain improvement is the glucoamylase-producing strain Aspergillus niger SP56, its enzyme activity is 20,000 units/ml, 4 times of that of the parental strain UV-11. Recently, recombinant DNA approach provides a worthwhile alternative strategy to industrial strain improvement. This technique had been used by us to increase the thermostable .alpha.-amylase production and on some genetic researches.

• Journal of Microbiology and Biotechnology
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• v.14 no.3
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• pp.442-449
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• 2004

Improving the light utilization efficiency of photosynthetic cells in photobioreactors (PBRs) is a major topic in algal biotechnology. Accordingly, in the current study we investigated the effect and suitability of photosynthetic pigment reduction for improving light utilization efficiency. The light-harvesting complex II (LH-II) genes of Rhodobacter sphaeroides were removed to construct a mutant strain with less pigment content. The mutant strain exhibited a slower growth rate than the wild-type under a low light intensity, while the mutant grew faster under a high light intensity. In addition, the specific absorption coefficient was lower in the mutant due to its reduced pigment content, thus it seemed that light penetrated deeper into its culture broth. However, the distance (light penetration depth) from the surface of the PBR to the compensation point did not increase, due to an increase in the compensation irradiance of the mutant strain. Experimental data showed that a reduced photosynthetic pigment content, which lessened the photoinhibition under high-intensity light, helped the volumetric productivity of photosynthetic microorganisms.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.269-272
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• 2004

The present study used a diagrammatic analysis of 6 sigma quality control and Taguchi method for injection molding process of monitor back-cover, evaluated the influence on the cycle time with part design, mold design, molding process and standardization activity involving design & molding, adopted analysis of sensitivity and effective factors of the part design and molding process conditions for productivity, identified main design molding factors, as critical ones influencing on the quality and productivity, of which is summarized as design guidance. The main contribution factors for cycle time can be sequentially enumerated as follows; hot spot, part thickness, coolant inlet temperature, melt temperature cooling line layout, etc.. As a first step critical factors of the design process of current monitor housing were investigated. And the optimal and better critical factors found in the first step were applied to a new product proving our process was correct. Moldflow software was used for injection molding simulation, and Minitab software for the statistical analysis. Finally, the productivity was increased by about 33 percents for our specific case.

• Health Policy and Management
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• v.9 no.4
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• pp.87-119
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• 1999

The main purpose of this research is to measure and analyze how productive the health centers are and how much inputs(or outputs) in the inefficient health centers should be decreased(or increased) for efficiency. The evaluation of the performance of health centers gives a strong incentive to improve resource allocation in regional health planning. It has been, however, implemented very rarely until now. In this regard, this paper measures the performance of the health centers with a single indicator for multiple-outputs in terms of productivity(technical efficiency), based on Data Envelopment method. The 20 Kyungnam health centers which provide clinic services and specific primary health care services were analyzed. The results show that 50.0% of 20 health centers were productive with respective to overall technical efficiency, 65.0% were productive for pure technical efficiency, and 50.0% for scale efficiency. The inefficient group includes Geoje, Mahsan, Miryang, Sahchun, Tongyoung, Gosung, Nahmhae, Euryang, Hahmahn, Hahbchun health centers. The worst case was identified as Tongyoung health center which represented a 47.5% efficiency, compared with productive health centers. The empirical results for input-output analysis indicates that the low-productive health centers have excessive manpower in administration department, producing low outputs in clinical services and vaccination program. These findings imply that a systemic evaluation of the performance of the Korean health centers and the subsequent structural reform are strongly required.

• The Microorganisms and Industry
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• v.15 no.1
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• pp.38-42
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• 1989

Industrial strain Improvement is concerned with developing or modifying microorga-nisms used In production of commercially important fermentation products. The aim is to reduce the production cost by improving productivity of a strain and manipulating specific cilarafteristic such as the ability to utilize cheaper raw materials or resist bacteriophages. The traditional empiri-cal approach to strain improvement is mutation combined with selection and breeding techniques. It is still used by us to improve the productivity of organisms in amino acids. organic acids andenzymes production. The breeding of high L-lysine-producing strain Au112 is one of the outstanding examples of this approach. It is it homoserine auxotroph with AEC, TA double metabolicanalogue resistant markers. The yield reaches 100g/1. Resides, the citric acid-producing organism Aspergillus nuger, Co827, its productivity reches the advanced level in the world, is also the result of a series mutations expecially with Co Y-radiation. The thermostable a-amylaseroducing strain A 4041 is the third example. By combining physical and chemical multations. the strain ,A 4041becomes an asporogenous, catabolite derepressed mutant with rifamycin resistant and methionine, arginine auxotroph markers. The a-amylase activity reaches 200 units/ml. The fourth successful example of mutation in strain improvement is the glucoamylase-producing strain Aspergillus nigerSP56 its enzyme activity is 20,000 units/ml, 4 times of that of the parental strain UV_11. Recently recombinant DNA approach Provides a worth while alternative strategy to Industrial strain improve-ment. This technique had been used by us to increase the thermostable a-amylase production and on some genetic researches.

• Journal of Marine Bioscience and Biotechnology
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• v.8 no.1
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• pp.24-29
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• 2016

Microalgae are considered as superior biodiesel producers, because they could effectively produce high amount of lipid with fast growth rate. In this study, Chlorella vulgaris was exposed to various light wavelengths (${\lambda}_{max}$ 470 nm, ${\lambda}_{max}$ 525 nm, and ${\lambda}_{max}$ 660 nm) using light emitting diodes (LEDs) to examine effect of light quality on their growth and fatty acid production in 0.4-L bubble column photobioreactors. Fluorescent lamps were also used as polychromatic light sources (control). From the results, biomass productivity was varied by light wavelength from 0.05 g/L/day to 0.30 g/L/day. Maximum biomass productivity was obtained from red LED among tested ones. We also observed that contents of oleic acid and linolenic acid, which affect biodiesel properties, were significantly changed depending on supplied wavelength. These results indicated that production of algal biomass, and fatty acid content and productivity could be improved or controlled by supplying specific light wavelength.

• Journal of Environmental Science International
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• v.28 no.10
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• pp.887-898
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• 2019

Rehabilitation work is required to increase well productivity, which decreases with the elapsed time of pumping owing to the clogging of the water well. Clogging causes not only a reduction in the well productivity but also a deterioration of the water quality. For unclogging and rehabilitating wells, several techniques are used such as brushing, air surging, surge blocks, and gas impulse. In this study, the high-pressure air impulse technique, which effectively and economically rehabilitates wells, was applied to a riverbank filtration site in Korea for the same objective. At most of the wells, the hydraulic parameters (transmissivity, storage coefficient, and specific capacity) were increased by the application of the high-pressure air impulse technique. The well loss change values also indicate an increase in the hydraulic parameters by the air impulse implementation. Thus, the high-pressure air impulse technique can be efficiently and economically applied to water and riverbank filtration wells for rehabilitating the decreased productivity.

• Journal of the Korean Wood Science and Technology
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• v.47 no.6
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• pp.751-760
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• 2019

Cellulase is an eco-friendly biocatalyst, and its demand is growing in many industrial applications such as food, textile, paper, and bioenergy. Strains with a high cellulase activities are the starting point for the economic production of cellulase. In a previous study, Acanthophysium sp. KMF001 with high cellulase production ability was selected among 54 wood-rotting fungi. In this study, we evaluated the cellulase productivity of Acanthophysium sp. KMF001 quantitatively and analyzed its taxonomic location using a genetic method. Acanthophysium sp. KMF001 showed high cellulase productivity similar to that of Acanthophysium bisporum and was much better than A. bisporum in specific enzyme activity. The 28S rRNA sequence of Acanthophysium sp. KMF001 was similar to that of Acanthophysium lividocaeruleum MB1825, with 98.40% homology. Phylogenetic analysis suggested that Acanthophysium sp. KMF001 is a new strain. In this study, we propose a new strain with high cellulase productivity.