• Journal of the Korean Society for Precision Engineering
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• v.20 no.8
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• pp.39-46
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• 2003

Productivity and machining performance can be improved by cutting analysis including cutting force prediction, surface error prediction and machining stability evaluation. In order to perform cutting analysis, cutting force coefficients database have to be constructed. Since cutting force coefficients are dependent on cutting condition in the existing research, a large number of calibration tests are needed to obtain cutting force coefficients, which makes it difficult to build the cutting force coefficients database. This paper proposes a generalized method for constructing the cutting force coefficients database us ins cutting-condition-independent coefficients. The tool geometry and workpiece material were considered as important components for database construction. Cutting force coefficients were calculated and analyzed for various helix and rake angles as well as for several workpiece. Furthermore, the variation of cutting force coefficients according to tool wear was analyzed. Tool wear was found to affect tool geometry, which results in the change of cutting force coefficients.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.8
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• pp.185-193
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• 2003

The modular self-wiping co-rotating twin screw extruder (SWCOR) has become the most important of twin screw machines. Screw design is one of the most important factors in determining performance of screw extruder. The screw flight and screw channel geometry of SWCOR is determined by the screw diameter, centerline distance, helix angle, and flights number. The maximum allowable throughput rate on a twin screw extruder is determined by a combination of free volume and available specific torque. In this paper we designed geometrical parameters of extruder screw and presented optimal specific torque value in K=1.55, and then developed screw design program for the screw cutting by the use of JAVA API in the twin screw extruder.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.2
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• pp.215-225
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• 1988

The curved structures in space, such as multi-level interchanges, ramped structures, and circular curved structures can be modelled as helically curved members with constant helix angle. This paper presents a finite element approach for the analysis of the static and the free vibration characteristics of the helically curved members by using the 7th order Hermite interpolation functions. This method is used to find more accurate solution of the static and dynamic responses of them than those of the previous studies.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.2
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• pp.163-168
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• 2001

We isolated and sequenced a cDNA clone corresponding to apolipophorin-III (apoLp-III) from the fall webworm, Hyphantria cunea. The cDNA for apoLp-III codes fer a 187-residue protein (561 bp) with a predicted molecular mass of 20 kDa. The calculated isoelectric point is 8.76. Multiple alignment analysis of the amino acid sequence revealed that H. cunea apoLp-III is most similar to that of Spodoptera litura (71.5% identity), followed by that of Manduca sexta (69.7% identity). They share five amphipathic $\alpha$-helices that are proposed to play a critical role in the binding of apoLp-III to lipophorin.

• Bulletin of the Korean Chemical Society
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• v.18 no.9
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• pp.933-938
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• 1997

The interaction of mastoparan B, a tetradecapeptide toxin found in the hornet Vespa basalis, with phospholipid bilayers was investigated. Synthetic mastoparan B and its analogs, obtained by substituting one hydrophilic amino acid (2-Lys, 4-Lys, 5-Ser, 8-Ser, 11-Lys, or 12-Lys) in mastoparan B with Ala, were studied. Mastoparan B and its analogs were synthesized by the solid-phase method. As shown by circular dichroism spectra, mastoparan B and its analogs adopted an unordered structure in buffer solution. All peptides took an α-helical structure, and the α-helical content of its analogs increased in the presence of neutral and acidic liposomes as compared to that of mastoparan B. In the calcein leakage experiment, we observed that mastoparan B interacted more weakly with lipid bilayers in neutral and acidic media than its analogs. Mastoparan B also showed slightly lower antimicrobial activity and hemolytic activity towards human erythrocytes than its analogs. These results indicate that the greater hydrophobicity of the amphiphilic α-helix of mastoparan B by replacement with alamine residues results in the increased biological activity and helical content.

• The korean journal of orthodontics
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• v.51 no.6
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• pp.428-434
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• 2021

Craniofacial clefts are extremely rare deformities. Tessier's classification is a widely accepted system that is based on clinical, radiographical, and surgical observations. The Tessier No. 0 cleft most commonly affects the upper lip, nose, and palate. This case presentation aims to report the outcome of a modified presurgical alveolar molding (PAM) appliance used in the treatment of an infant with Tessier No. 0 cleft as an alternate approach to mold such defects before surgery. The modified PAM appliance consisted of reciprocal parts connected by a helix. The segments were approximated by stripping the appliance at the midline in a V-shaped manner and the force was exerted by the extraoral elastics. The procedure gave results in 8 weeks, which may be regarded as a reasonable duration. The anterior cleft gap, which was 13 mm before the treatment, was reduced to 3 mm after the treatment by using modified PAM appliance. On a 21-month follow-up period, oral reshaping was regarded successful due to stability of the improved oral mold.

• Journal of People, Plants, and Environment
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• v.22 no.4
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• pp.365-373
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• 2019

This study was conducted to determine the effects of horticultural therapy on self-esteem of women with hearing impairment. Ten women with hearing impairment registered in the Mokpo Branch of the Korean Association of the Deaf participated in the horticultural therapy programs (HTP) for self-esteem. The self-esteem scale was used to evaluate the effects of the programs and scores were compared to determine the difference before and after the programs. Self-esteem was improved in all 10 subjects, and its mean value increased with statistical significance from 22.5 points before the programs to 29.8 points after the programs. The programs preferred by women with hearing impairment included 'making a centerpiece using scented candles and flowers', 'packing and planting pot spray chrysanthemum', 'making a topiary', 'planting Hedera helix', and 'planting cyclamen'. Therefore, it was suggested that self-esteem of women with hearing impairment were improved by increasing social and family support, emotional stability, positive feedback, and self-expression through horticultural therapy programs.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.3
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• pp.363-372
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• 2000

An experiment was carried out to evaluate the heat transfer enhancement and the pressure drop characteristics for liquid nitrogen using wire-coil-insert technique under horizontal two-phase conditions. The tube inner diameters were 8 mm and 15 mm, respectively and the tube length was 4.7 m. The helix angle of the wire coil insert was $50^{\circ}$ and its length was 4.7 m. Heat transfer coefficients for both the plain and the enhanced test tubes were calculated from the measurements of temperatures, flow rates and pressure drops. A correlation in a power-law relationship of the Nusselt number, Reynolds number and Prandtl number for the heat transfer was proposed which can be available for design of cryogenic heat exchangers. The correlation showed that heat transfer coefficients for the wire-coil inserts were much higher than those for plain tubes, increased by more than $1.8{\sim}2.0$ times depending upon the range of the equivalent Reynolds number. The correlation was compared with other various correlations in the turbulent flow conditions.

• Archives of Pharmacal Research
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• v.21 no.3
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• pp.291-297
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• 1998

Cop protein has been overexpressed in Escherichia coli using a T7 RNA polymerase system. Purification to apparent homogeneity was achieved by the sequential chromatography on ion exchange, affinity chromatography, and reverse phase high performance liquid chromatography system. The molecular weight of the purified Cop was estimated as 6.1 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). But the molecular mass of the native state Cop was shown to be 19 kDa by an analytical high performance size exclusion chromatography, suggesting a trimer-like structure in 50 mM Tris-HCI buffer (pH 7.5) containing 100 mM NaCl. Cop protein Was calculated to contain $39.1% {\alpha}-helix, 16.8% {\beta}-sheet$, 17.4% turn, and 26.8% random structure. The DNA binding property of Cop protein expressed in E. coli Was preserved during the expression and purification process. The isoelectric point of Cop was determined to be 9.0. The results of amino acid composition analysis and N-terminal amino acid sequencing of Cop showed that it has the same amino acid composition and N-terminal amino acid sequence as those deduced from its DNA sequence analysis, except for the partial removal of N-terminal methionine residue by methionyl-aminopeptidase in E. coli.

• Journal of Chest Surgery
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• v.6 no.1
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• pp.69-88
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• 1973

Twenty-one cases of open mitral commissurotomy were done between October 1963 and March 1973. 1] Preoperative embolism consists of 7 cerebral and 2 peripheral cases. Two operative cerebral embolism cases were noted. 2] There were two cases of restenosis, one associated valvular disease, three mitral insufficiency cases, and six cases of pulmonary hypertension. 3] Out of 21 cases, 13 cases of atrial fibrillation were found and two cases of atrial fibrillation were found postoperatively among 8 cases of preoperatively normal sinus rhythm. 4] During operation 10 cases of valvular calcification and 6 cases of left atrial thrombus were noted. 5] Complete blood count, electrolyte and acid base balance showed normal range of data. 6] Four helix reservoir whole blood total body perfusion and 17 cases of .hemodilution perfusion utilizing Rygg-Kyvsgaard bag oxygenator with sigma motor were performed. 7] EACA 125 mg/kg intravenous administration before cardiopulmonary bypass resulted in markedly diminished postoperative bleeding. 8] Post-perfusion urine amount was in satisfactory range. 9] There were 2 operative mortality due to coronary embolism and three cases of hospital death, 2 due to severe hepatic failure and one due to cerebral embolism. 10] Sixteen survival cases showed marked clinical improvements and almost all of them returned to their occupation satisfactorily after operation.