• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.1
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• pp.57-70
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• 2009

Considerable advance has been made on research on effect of steel pipe Umbrella Arch Method (UAM) and mechanical reinforcement mechanism through numerical analyses and experiments. Due to long analysis time of three-dimensional analysis and its complexity, un-quantitative two-dimensional analysis is dominantly used in the design and application, where equivalent material properties of UAM reinforced area and ground are used, For this reason, development of reasonable, theoretical, quantitative and easy to use design and analysis method is required. In this study, both field UAM tests and laboratory tests were performed in the residual soil to highly weathered rock; field tests to observe the range of reinforcement, and laboratory tests to investigate the change of material properties between prior to and after UAM reinforcement. It has been observed that the increase in material property of neighboring ground is negligible, and that only stiffness of steel pipe and cement column formed inside the steel pipe and the gap between steel pipe and borehole contributes to ground reinforcement. Based on these results and concept of Convergence Confinement Method (CCM), two dimensional axisymmetric analyses have been performed to obtain the longitudinal displacement profile (LDP) corresponding to arching effect of tunnel face, UAM effect and effect of supports. In addition, modified load distribution method in two dimensional plane-strain analysis has been suggested, in which effect of UAM is transformed to internal pressure and modified load distribution ratios are suggested. Comparison between the modified method and conventional method shows that larger displacement occur in the conventional method than that in the modified method although it may be different depending on ground condition, depth and size of tunnel, types of steel pipe and initial stress state. Consequently, it can be concluded that the effect of UAM as a beam in a longitudinal direction is not considered properly in the conventional method.

• Korean Journal of Materials Research
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• v.4 no.8
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• pp.906-914
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• 1994

Plastic behavior of two-phase intermetallic compounds based on $LI_{2}$-type $(Al, Cr)_3$ Ti was investigated using compression test at R.T. and 77K. $LI_{2}$ single phase alloys and two-phase alloys consisting of mainly $LI_{2}$ phase and a few or 20% second phases were selected from AI-Ti-Cr phase diagram. In general, compared with Llz single phase, two-phase alloys consisting of 20% second phase showed relatively high yield strength and poor ductility. Among the alloys, however, AI-21Ti-23Cr alloy consisting of 20% $Cr_{2}Al$ phase showed available ductility as well as high yield strength. Plastic behavior of $LI_{2}$ single phase alloys and two-phase alloys consisting of a few% $Cr_{2}Al$ was also investigated. Homogenization of arc melted ingots substantially reduced the amount of second phases but introduced extensive pore. When Cr content increased in $Ll_{2}$ single phase alloys after the homogenization, the volume fraction of pore in the alloys decreased, and no residual pore was observed in two-phase alloys consisting of a few% $Cr_{2}Al$ phase. Environmental effect on the ductility of the alloys was investigated using compression test at different strain rates($1.2 \times 10^{-4}/s$ and $1.2 \times 10^{-2}/s$). Environmental embrittlement was least significant in A1-25Ti-10Cr alloy consisting of LIZ single phase among the alloys tested in this study. However, based on the combined estimation of the pore formation, environmental embrittlement and ingot cast structure, AI-21Ti-23Cr alloy consisting of 20% $Cr_{2}Al$ as the second phase is expected to show the best tensile elongation behavior.

• Journal of Mushroom
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• v.13 no.1
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• pp.56-62
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• 2015

A lipase producing bacterium was isolated from button mushroom bed, which showing high clear zone on agar media containing Tributyrin as the substrate. The strain was identified as Burkholderia cepacia by analysis of 16S rDNA gene sequence. Crude lipase (CL) was partially purified from 70% ammonium sulfate precipitation using the culture filtrate of B. cepacia. Immobilized lipases were prepared by cross-linking method with CL from B. cepacia and Novozyme lipase (NL) onto silanized Silica-gel as support. Residual activitiy of the immobilized CL (ICL) and immobilized NL (INL) was maintained upto 61% and 72%, respectively. Biodiesel (Fatty acid methyl ester, FAME) was recovered by transesterification and methanolysis of Canola oil using NaOH, CL and ICL as the catalysts to compare the composition of fatty acids and the yield of FAME. Total FAME content was NaOH $781mg\;L^{-1}$, CL $681mg\;L^{-1}$ and ICL $596mg\;L^{-1}$, in which the highest levels of FAME was observed to 50% oleic acid (C18:1) and 22% stearic acid (C18:0). In addition, the unsaturated FAME (C18:1, C18:2) decreased, while saturated FAME (C16:0, C18:0) increased according to increasing the reaction times with both CL and ICL, supporting CL possess both transesterification and interesterification activity. When reusability of ICL and INL was estimated by using the continuous reaction of 4 cycles, the activity of ICL and INL was respectively maintained 66% and 79% until the fourth reaction.

• Journal of Chest Surgery
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• v.35 no.7
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• pp.530-534
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• 2002

Background: In aortic surgery, division and ligation of the left brachiocephalic vein(LBV) may improve exposure of the aortic arch but controversy continues about the safety of this division and whether a divided vein should be reanastomosed after arch replacement was completed. The safety of LBV division and the fate of the left subclavian venous drainage after LBV division were studied. Material and Method: From November 1998 to January 2001, planned division and ligation of the LBV on the mid-line after median sternotomy was peformed in 10 patients during the aortic surgery with the consideration of local anatomy and distal aortic anastomosis. Assessment for upper extremity edema and neurologic symptoms, measurement of venous pressure in the right atrium and left internal jugular vein, and digital subtraction venography(DSV) of the left arm were made postoperatively. Result: In 10 patients there was improvement in access to the aortic arch for procedures on the ascending aorta or aortic arch. The mean age of patients was 62 years(range 24 to 70). Follow-up ranged from 3 weeks to 13 months. One patient died because of mediastinitis from methicilline-resistant staphylococcus aureus strain. All patients had edema on the left upper extremity, but resolved by the postoperative day 4. No patient had any residual edema or difficulty in using the left upper extremity during the entire follow-up period. No patient had postoperative stroke. Pressure difference between the right atrium and left internal jugular vein was peaked on the immediate postoperative period(mean peak pressure difference = 25mmHg), but gradually decreased, then plated by the postoperative day 4. In all DSV studies left subclavian vein flowed across the midline through the inferior thyroid venous plexus. Conclusion: We conclude that division of LBV is safe and reanastomosis is not necessary if inferior thyroid vein, which is developed as a main bridge connecting the left subclavian vein with right venous system, is preserved.

• Applied Biological Chemistry
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• v.15 no.2
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• pp.111-142
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• 1972

An experimental Chung-Kook-Jang was prepared using the strain Bacillus subtilis sp. isolated by the author Samples were taken in 12 hrs interval during the fermentation and the oligopeptides were separated by the method of molecular sieving using the ion exchange resin column of Dowex-50. Only the X-16 fraction of oligopeptides was taken and the components of oligopeptides were developed in two dimensional thin layer chromatograms. The each peptide spot was eluted and each peptide was isolated. The pattern and kinds of amino acids, and N and C-terminal amino acids were studied. Fourteen different oligopeptides could be detected by the two dimensional thin layer chromatography, all of which were consisted of $4{\sim}9$ kinds of amino acids. No dipeptides and no tripeptides could be found. The N and C-terminal amino acids and the residual component amino acids of all these 14 peptides could be summarized as the follows. [P]-I. Pro (Cys Ala Asp Trp Ile Val) Glu [P]-II. Val (His Arg Glu Thr Ala Met) Asp [P]-III. Glu (Cys Lys Asp Thr Met) Ala [P]-IV. Glu(His Ser Ala) Met) [P]-V. Ile (Cys Asp Arg Gly Pro T.p Phe) His [P]-VI. Gly(Asp ser) Lys [P]-VII. Thr(Pro Tyr Phe) Asp [P]-VIII. Phe(Tyr Leu Ile) Val [P]-IX. Trp (Phelle) Thr [P]-X. Ile (Arg Leu) Phe [P]-XI. Asp (Lys His Ser Gly Glu Pro) Ala [P]-XII. Glu (Cys Asp Gly) Ser [P]-XIII. Ala (Arg Tyr) Glu [P]-XIV. Met (Glu Ala) His It appears that the protease of the Bacillus subtilis K-27 syrain has rather wider range of specificity than proteases of Aspergoillus soya, pepsin, chymotrypsin, and trypsin.

• Food Science and Preservation
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• v.20 no.5
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• pp.744-750
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• 2013

The indigenous Saccharomyces cerevisiae strains S13 and D8 were isolated at the microbial succession stage during spontaneous fermentation of Campbell Early wine as a resistant to potassium metabisulfite and a high sugar concentration. In this study, the fermentation characteristics of Campbell Early wine were investigated and compared with those of S. cerevisiae W-3, an industrial wine yeast. Alcohol production by the two strains was delayed at the initial fermentation stage, but increased fast when the fermentation continued. After the fermentation, the S13 and D8 wines contained 12.6% and 13.2% (v/v) alcohol, respectively, which were significantly higher than the alcohol content of the W-3 wine (12%, v/v). No marked differences were observed in the residual soluble solid content and the pH. However, the S13 and D8 wines showed high levels of total acid content, including malic and lactic acids. Especially, the lactic acid content was 8.9-fold in the S13 wine and six-fold in the D8 wine, compared with that of the W-3 wine. The two strains produced a higher level of acetaldehyde and a lower amount of methanol in the wine than the W-3 strain. The iso-Butanol content was lower in the two indigenous yeast wines with similar levels of n-propanol and iso-amyl alcohol contents than that in the W-3 wine. In the sensory evaluation, the S13 and D8 wines had higher scores for their color, flavor, taste and overall preferences than the W-3 wine. Especially, the S13 and D8 wines had much higher scores than the W-3 wine for flavor and color, respectively.

• Journal of the Korean Geotechnical Society
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• v.23 no.9
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• pp.5-16
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• 2007

The simple linear elastic-perfectly plastic model with soil parameters $s_u,\;E_u$ and n of undrained condition is usually applied to predict the displacement of a constructed diaphragm wall(DW) on soft soils during excavation. However, the application of this soil model for finite element analysis could not interpret the continued increment of the lateral displacement of the DW for the large and deep excavation area both during the elapsed time without activity of excavation and after finishing excavation. To study the characteristic behaviors of soil behind the DW during the periods without excavation, a series of tests on soft Bangkok clay samples are simulated in the same manner as stress condition of soil elements happening behind diaphragm wall by triaxial tests. Three kinds of triaxial tests are carried out in this research: $K_0$ consolidated undrained compression($CK_0U_C$) and $K_0$ consolidated drained/undrained unloading compression with periodic decrement of horizontal pressure($CK_0DUC$ and $CK_0UUC$). The study shows that the shear strength of series $CK_0DUC$ tests is equal to the residual strength of $CK_0UC$ tests. The Young's modulus determined at each decrement step of the horizontal pressure of soil specimen on $CK_0DUC$ tests decreases with increase in the deviator stress. In addition, the slope of Critical State Line of both $CK_0UC$ and $CK_0DUC$ tests is equal. Moreover, the axial and radial strain rates of each decrement of horizontal pressure step of $CK_0DUC$ tests are established with the function of time, a slope of critical state line and a ratio of deviator and mean effective stress. This study shows that the results of the unloading compression triaxial tests can be used to predict the diaphragm wall deflection during excavation.

• Journal of Korean Society of Forest Science
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• v.59 no.1
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• pp.67-91
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• 1983

In order to examine the alcohol production from softwoods (Pinus densiflora Sieb. et Zucc., Pinus rigida Miller, Larix leptolepis Gordon) and hardwoods (Alnus japonica Steud., Castanea crenata Sieb. et Zucc. Populus euramericana CV 214), chemical compositions were analyzed and conditions of acid hydrolysis with wood meals were established. Also strains which could remarkably decompose the cellulose were identified, and conditions of cellulase production of strains, characteristics of cellulase, and alcohol fermentation were examined. The results were summarized as follows. 1) In acid hydrolysis of wood, the high yield of reducing sugars was shown from 1.0% to 2.0% of hydrochloric acid and 2.0% of sulfuric acid. The highest yield was produced 23.4% at wood meals of Alnus japonica treated with 1.0% of hydrochloric acid. 2) The effect of raising the hydrolysis was good at $1.5kg/cm^2$, 30 times (acid/wood meal), and 45 min in treating hydrochloric acid and 30 min in treating sulfuric acid. 3) The pretreatments with concentrated sulfuric acid were more effective concentration ranged from 50% to 60% than that with hydrochloric acid and its concentration ranged from 50% to 60%. 4) The quantative analysis of sugar composition of acid hydrolysates revealed that glucose and arabinose were assayed 137.78mg and 68.24mg with Pinus densiflora, and 102.22mg and 65.89mg with Alnus janonica, respectively. Also xylose and galactose were derived. 5) The two strains of yeast which showed remarkably high alcohol productivity were Saccharomyces cerevisiae JAFM 101 and Sacch. cerevisiae var. ellipsoldeus JAFM 125. 6) The production of alcohol and the growth of yeasts were effective with the neutralization of acid hydrolysates by $CaCO_3$ and NaOH. Production of alcohol was excellent in being fermented between pH 4.5-5.5 at $30^{\circ}C$ and growth of yeasts between pH 5.0-6.0 at $24^{\circ}C$. 7) The production of alcohol was effective with the addition of 0.02% $(NH_2)_2CO$ and $(NH_4)_2SO_4$, 0.1% $KH_2PO_4$, 0.05% $MgSO_4$, 0.025% $CaCl_2$, 0.02% $MnCl_2$. Growth of yeasts was effective with 0.04-0.06% $(NH_2)_2CO$ and $(NH_4)_2SO_4$, 0.2% $K_2HPO_4$ and $K_3PO_4$, 0.05% $MgSO_4$, 0.025% $CaCl_2$, and 0.002% NaCl. 8) Among various vitamins, the production of alcohol was effective with the addition to pyridoxine and riboflavin, and the growth of yeasts with the addition to thiamin, Ca-pantothenate, and biotin. The production of aocohol was increased in 0.1% concentration of tannin and furfural, but mas decreased in above concentration. 9) In 100ml of fermented solution, alcohol and yeast were produced 2.201-2.275ml and 84-114mg for wood meals of Pinus densiflora, and 2.075-2.125ml and 104-128mg for that of Alnus japonica. Residual sugars were 0.55-0.60g and 0.60-0.65g for wood meals of Pinus densiflora and Alnus japonica, respectively, and pH varied from 3.3 to 3.6. 10) A strain of Trichoderma viride JJK. 107 was selected and identified as its having the highest activity of decomposing cellulose. 11) The highest cellulase production was good when CMCase incubated for 5 days at pH 6.0, $30^{\circ}C$ and xylanase at pH 5.0, $35^{\circ}C$. The optimum conditions of cellulase activity were proper in case of CMCase at pH 4.5, $50^{\circ}C$ and xylanase at pH 4.5, $40^{\circ}C$. 12) In fermentation with enzymatic hydrolysates, the peracetic acid treatment for delignification showed the best yields of alcohol and its ratio was effective with the addition of about 10 times. 13) The production of alcohol was excellent when wood meals and Koji of wheat bran was mixed with 10 to 8 and the 10g of wood meals of Pinus densiflora produced 2.01-2.14ml of alcohol and Alnus japonica 2.11-2.20ml.