• Journal of the Optical Society of Korea
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• v.7 no.4
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• pp.264-268
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• 2003

A new approach to design binary phase holograms, with less computation time and equal effi-ciency compared with the genetic algorithm method, is proposed. Synthesized holograms having diffraction efficiency of 75.8% and uniformity of 5.8% are tested in computer simulation and experimentally demonstrated.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.8
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• pp.2167-2176
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• 1994

This paper presents some useful design criteria for the turbine cogeneration system through both the design and off-design analysis. Comparative analysis of the part load performance is carried out for several gas turbines which have different design parameters represented by the turbine inlet temperature and pressure ratio. It is shown that the variation in part load efficiency considerably depends on the design parameter. The off-design operation of the heat recovery steam generator is simulated by introducing adequate assumptions for the heat transfer process. It is turned out that the design parameters of heat recovery steam generator should be determined by considering the favorable operation at the off-design conditions.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.4
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• pp.269-273
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• 2001

This study presents a new formulation method for improving DNA transfection effi-ciency using a fusogenic peptide and polyethylene glycol-grafted polyethylenimine. Succinimidyls succinate polyethylene glycol (PEG-SSA) was conjugated with polyethylenimine(PEL). PEL is well known for a good endosomal escaping and DNA condensign agent. The positively charged syn-thetic fusogenic peptide, KALA was coated on the negatively charged PEG-g-PEI/DNA and PEI/DNA complexes. The KALA/PEI/ DNA complexes exhibited aggregation behavior at higher KALA coating amount with an effective diameter of around 1,000 nm. However, the LALA/PEG-g-PEI/DNA complexes were 100-300 nm in size with a surface zeta-potential (ζ)value of about +20mV. The conjugated PEG molecules suppressed any KALA-mediated inter-particle aggregation, and thereby improved the transfection efficiency, Consequently, the transfection efficiency of the KALA/PEG-g-PEI/DNA complexes was obtained by utilizing both the fusogenic activity of KALA and the steric repulsion effect of PEC.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.5
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• pp.687-694
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• 1999

This study was conducted to develop new drying process for automatic control and marine engi-neering system. Air-water tests were carried out to investigate dryer performance. The dispersed flow in he dryer test apparatuses was also simulated by using a numerical code which solves the Dittus-Boelter equation for continuous liquid phase and the Reynolds equation of droplet motion for continuous liquid phase and the Reynolds equation of droplet motion for dispersed phase to predict droplet removal efficiency. Proper conditions for dehumidification were optimized by response ambient conditions. When the selected indexes were constrained in the range of 85-98% moisture content above $15^{\circ}$ and more than mass flow rates of moist air 750kg/h. The numerical results were compared with the experimental data pertaining to the removal effi-ciency at chamber stage and overall pressure drop along concentric tubes Good agreement was obtained as for the efficiency while relatively poor agreement was obtained for the relative humidity. The results also showed that the efficiency depended strongly on the relative humidity at the inlet condition which indicated the importance of estimating the heat exchanger length. Effects of some design parameters in both removal efficiency and breakthrough onset condition are discussed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.409-416
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• 1999

Microwave extraction system equipped with closed vessels was applied to confirm its capability of extracting ginseng solubles including saponin, which was monitored to optimize extraction con ditions by response surface methodology. Total yield increased with the decrease in particles size and more extraction steps. Soluble components were completely extracted by operating the system within 6 min per one step, which should be repeated by 3 or 4 times. Optimized conditions for maxi mum extraction of response variables(total yield, crude saponin) were 40~50% of ethanol concentration, about 140oC of extraction temperature, and within 6 min of the extraction time. The extraction effi ciency of total yield was dependent on the decrease of ethanol concentration, while crude saponin content was favored on the higher degree of ethanol concentration. According to the temperature guideline, below 90oC of extraction temperature, the optimal ranges of extraction conditions were predicted as 30~50% of ethanol concentration and 2.5~6.5 min of extraction time. Estimated values of total yield and crude saponin were in good agreement with experimental values.

• The Journal of the Korean bone and joint tumor society
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• v.16 no.1
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• pp.8-13
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• 2010

Purpose: This study was performed to evaluate the effi ciency of Platelet-rich plasma (PRP) for acceleration of bone healing process on allograft transplantation after curettage in benign bone tumor. Materials and Methods: From December 2007 to February 2009, twenty-one patients who had benign bone tumor and underwent allograft transplantation after curettage were evaluated. Mean follow-up period was 14.6 months (range, 12-26 months). We compared with 13 cases of PRP group and 8 cases of non-PRP group in terms of size of lesion, bone resorption, amount of applied PRP and complications. The mean age at surgery was 23.6 years (range, 4-73 years). The most common diagnosis was simple bone cyst (7) followed by enchondroma (4), giant cell tumor (3), undifferentiated benign bone tumor (3) and so on. Results: The mean size of lesion was 33.5 $cm^3$ (range, 2.3-181.9 $cm^3$) (29.4 $cm^3$ in PRP group and 40.2 $cm^3$ in non-PRP group). The mean volume of injected PRP was 7.4 cc (range, 3-12 cc). Bone union started at 3.0 months (range, 1.5-5.8 months) in PRP group and 5.3 months (range, 4-8 months) in non-PRP group. Three cases for each group were excluded due to recurrence and pathologic fracture. One patient had febrile episode 3 weeks later after surgery which subsided with antibiotics. Conclusion: The PRP could accelerate bone union in allograft transplantation after curettage of benign bone tumor. Furthermore, we expect that PRP can accelerate bone union in fracture or non-union.