• Geomechanics and Engineering
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• v.11 no.2
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• pp.253-267
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• 2016

The stability of surrounding rock will be poor when the tunnel is excavated through nearly horizontal stratum. In this paper, the instability mechanism of local nearly horizontal stratum in super-large section and deep buried tunnel is revealed by the analysis of the macro failure and micro fracture. A structural model is proposed to explain the mechanics of surrounding rock collapse under the action of stress redistribution and shed light on the macroscopic analytical approach of the stability of surrounding rock. Then, some highly effective formulas applied in the tunnel engineering are developed according to the theory of mixed-mode micro fracture. And well-documented field case is made to demonstrate the effectiveness and accuracy of the proposed analytical methods of mixed-mode fracture. Meanwhile, in order to make the more accurate judgment about yield failure of rock mass, a series of comprehensive failure criteria are formed. In addition, the relationship between the nonlinear failure criterion and $K_I$ and $K_{II}$ of micro fracture is established to make the surrounding rock failure criterion more comprehensive and accurate. Further, the influence of the parameters related to the tension-shear mixed-mode fracture and compression-shear mixed-mode fracture on the propagation of rock crack is analyzed. Results show that ${\sigma}_3$ changes linearly with the change of ${\sigma}_1$. And the change rate is related to ${\beta}$, angle between the cracks and ${\sigma}_1$. The proposed simple analytical approach is economical and efficient, and suitable for the analysis of local nearly horizontal stratum in super-large section and deep buried tunnel.

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.677-684
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• 2013

A mixed refrigerant cycle (MRC) has been widely used in liquefaction of natural gas because it is simple and easily operable with reasonable equipment costs. One of the important techniques in MRC is selection of a refrigerant mixture and decision of its optimum mixing ratio. In this work, it is examined whether mixture components (refrigerants) and their mixing ratio influence performance of general MRC processes. In doing this, mixture design and response surface method, which are well-known statistical techniques, are used to find optimal mixture refrigerants and their optimal mixing ratio that minimize total energy consumption of the entire liquefaction process. A MRC process using several refrigerants and various mixing ratios is simulated by Aspen HYSYS and mixture design and response surface method are implemented using Minitab. According to the results, methane ($C_1$), ethane ($C_2$), propane ($C_3$) and nitrogen ($N_2$) are selected as best mixture refrigerants and the determined mixture ratio (mole ration) can reduce total energy consumption by up to 50%.

• Journal of Fashion Business
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• v.13 no.4
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• pp.178-190
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• 2009

The purpose of this study is to make reference for geometric fashion by investigating geometric patterns by linear types and to propose high value added print and fashion design by designing and producing geometric prints and apparel with them focusing on digital textile printing. As a method of the study, visual and textural data were investigated for theory of geometric pattern and fashion design samples were illustrated. The geometric pattern could be defined as abstract pattern which was crossed with straight line or curve. We could group it into three classes such as straight linear, curved, and mixed type. Images varied with linear types. The image of straight linear type was sharp and modern, that of curved one was soft and feminine and that of mixed one was gorgeous and artistic. And then, 3 geometric prints and 3 one-pieces were designed. The concept of design was simple optimism which was based on sixties. Target was young optimistic women group from the mid teens to the mid twenties who continued to seek after their unique individuality keeping their modern lifestyle. Geometric patterns with straight linear, curved, and mixed type were designed and dresses which went well with them were designed and produced. According to the result of this study, images of geometric fashion can be represented diversely by varying linear type, digital textile printing is good method for high value added geometric fashion because of its high quality and degree of sensitivity, and geometric pattern is a good source for contemporary fashion.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.99-105
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• 2000

The classifying distribution by the action style was opticion 100, photoartist 100, college student 100 for the simple myopic 35%, for the simple myopic astigmatism 2%, for the compound myopic astigmatism 30.6% for the mixed astigmatism 62.6% for the compound hyperopic astigmatism 37.4% for the ratio of emmetropia 22.4% respectively. The retractive erroreye were -0.50~-2.00Dptr for the simple myopia 14%, -2.00~-6.00Dptr 16%, -6.00Dptr 5%, C-0.25(90.180)~C-2.00DptrAxis(90, 180) 2% for the simple myopicastigmatismS-0.25C-0.25DptrAxis(90, 180)~S-1.00C-1.00DptrAxis (90, 180) 22.6%, S-1.00C-1.00 DptrAxis (90, 180)~S-2.00C-2.00DptrAxis(90, 180) 8% for the compound myopic astigmatism. S+0.25C -0.25DptrAxis(90, 180)~S+2.00C-2.00DptrAxis(90,180) 6.2% for the mixed astigmatism. S+0.25C+0.25DptrAxis(90,180)~S+1.00C+1.00DptrAxis(90,180) 3.4%, S+1.00C+1.00DptrAxis(90,180)~S+2.00C+2.00DptrAxis(90,180) 0.34% for the compound hyperopic astigmatism.

• Journal of Ocean Engineering and Technology
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• v.32 no.2
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• pp.95-105
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• 2018

An FLNG (floating liquefied natural gas) or LNG FPSO (floating production, storage and offloading) unit is a notable offshore unit with the increasing demand for LNG. The liquefaction process on an FLNG unit is the most important process because it determines the economic feasibility, but would be a hazard source because of the large quantity of hydrocarbons. While a high efficiency process such as C3MR has been preferred for onshore liquefaction processes, a relatively simple process such as the SMR (single mixed refrigerant) or DMR (dual mixed refrigerant) liquefaction process has been selected for offshore units because they require a more compact size, lighter weight, and higher safety due to their space limitation for facilities and long distance from shore. It is known that an SMR has the advantages of a simple configuration, small footprint, and lower risk. However, with an increased production rate, the inherent safety of SMR needs to be evaluated because of its small train capacity. In this study, the potential explosion risks of the SMR and DMR liquefaction processes were evaluated at the conceptual design stage. The results showed that an SMR has a lower overpressure than a DMR at the same frequency, only with a small production capacity of 0.9 MTPA. With increased capacity, the overpressure of the SMR was higher than that of the DMR. The increased number of trains increased the frequency in spite of the small amount of equipment per train. This showed that the inherent risk of an SMR is not always lower than that of a DMR, and an additional risk management strategy is recommended when an SMR is selected as the concept for an FLNG liquefaction process compared to the DMR liquefaction process.

• Journal of Life Science
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• v.27 no.10
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• pp.1145-1151
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• 2017

In this study, we report on a simple, efficient method for obtaining penicillin G amidase (PGA) from recombinant Escherichia coli using a formulation mixed with detergent and lysozyme. Research was conducted on the extraction efficiency of PGA from the periplasmic space in cells in terms of the type of detergent, detergent concentration, pH, reaction time, and temperature of permeabilization. The extraction yield of PGA in the formulated surfactant/lysozyme treatment was increased by approximately (55-65 U/ml) in comparison with that in the single surfactant treatment. The released PGA solution was concentrated and exchanged with buffer using an ultrafiltration (U/F) system. The yields of diatomite filtration, membrane filtration (M/F), and U/F were 69.7%, 93.8%, and 77.3%, respectively. A total of 212 KU of PGA was recovered. At the 25-L culture scale, the overall yield of extraction using the mixed surfactant/lysozyme method was 49.2%. The specific activity of extracted PGA was 11 U/mg in protein. The concentrated PGA solution was immobilized on microporous silica beads without further purification of PGA. The total immobilization yield of PGA on the resin was 48.7%, while the enzyme activity was 101 U/g. The immobilized PGA was successfully used to produce 6-APA from penicillin G. Our results indicated that a simple extraction method from periplasmic space in E. coli may be used for the commercial scale production of ${\beta}-lactam$ antibiotics using immobilized PGA.

• Journal of the Korean Magnetics Society
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• v.22 no.5
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• pp.157-161
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• 2012

Magnetism at the interfaces of rocksalt structured half-metals, NaN and CaN were investigated by use of the first-principles band calculations. The electronic structures for the simple interface and mixed interface systems were calculated by the FLAPW (full-potential linearized augmented plane wave) method. From the calculated number of electrons in muffin-tin spheres of each atom, we found, for the simple interface system, that the magnetic moment of the N atom in the CaN (NaN) side is increased (decreased) compared to those of inner N atoms. For the mixed interface system, the magnetic moments of the interface N atoms are similar to the averaged value for the inner N atoms in CaN and NaN side. Among four interface N atoms, the N atom connected to Na atoms in the upper and down layers has the largest magnetic moment and that connected to Ca atoms has the smallest. The number of p electrons in each N atom and the calculated density of states explain well the above situation.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.1
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• pp.65-69
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• 2001

To investigate the visual acuity of the primary school children. This study was researched visual acuity test using objective and subjective methods. 1. The eye types were 90.3% positive for myopia, 3.1% for emmetropia, 4.9% hyperopia, 1.7% for mired astigmatism. 2. The abnormal refraction eyes were 58.6% positive for simple myopia, 29.9% for myopic compound astigmatism, 5.1% for my optic simple astigmatism and 1.9% for simple hyperopia, 1.9% for hyperopic compound astigmatism, 1.3% for hyperopic simple astigmatism, 1.3% for mixed astigmatism. 3. The axis of astigmatism were 85.7% for astigmatism with-the-rule, 9.3% for astigmatism against-the-rule, 5.0% for astigmatism oblique. 4. On total myopic spheric power. the -0.50

• Journal of the Korean Orthopaedic Association
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• v.55 no.2
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• pp.169-177
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• 2020

Purpose: To assess the effectiveness of mixed grafts in lumbar posterolateral fusion (PLF) by comparing the bone union rates of an autobone with a bone substitute mixed graft. Materials and Methods: The patients were followed-up for at least two years after PLF and divided into four groups according to the mixed graft retrospectively. Group I was 48 cases using a femoral head allobone. Group II was 38 cases using β-tricalcium phosphate. Group III was 92 cases using biphasic calcium phosphate. Group IV was 38 cases using biphasic calcium phosphate and autologous bone marrow. Union was evaluated by the work up simple radiographs after two years from PLF. Union was defined if the radiographs demonstrated a bilateral continuity in the fusion mass between the cephalad and caudal transverse processes with less than 2° of angular motion and no translation between the vertebrae at the level of fusion on the lateral flexion-extension radiographs. Results: According to simple radiographs after two years from PLF, the rate of union was highest in Group IV using local autobone, biphasic calcium phosphate and autologous bone marrow mixed graft. Conclusion: Biphasic calcium phosphate is an osteoconductive bone substitute that increases the bio-absorbability and mechanical strength. Autologous bone marrow has osteoinductive and osteogenic properties. These features can increase the rate of bone union. Therefore, a local autobone, biphasic calcium phosphate and autologous bone marrow mixed graft can be considered an effective bone graft substitute for lumbar PLF instead of an autobone graft.

• Computational Structural Engineering
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• v.1 no.1
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• pp.67-78
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• 1988

A new method of element decomposition is suggested for simple, efficient, and generalized formulation of shell finite elements. The kernel of the method is to decompose conceptually the actual element into a translational element and a difference element. The actual element is obtained by combining the two component elements. The derived element can be classified into three basic types depending on how the element is decomposed. A few complementary measures, to remove locking phenomena and thus improve the performance of the elements, have been studied. They are reduced integration, addition of internal degrees of freedom, and mixed formulation. A rational method of controlling spurious zero energy modes has also been devised. Validity and efficiency of the element with or without complementary measures have been examined through a series of numerical studies.