• 한국정밀공학회지
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• 제33권11호
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• pp.927-935
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• 2016

A gerotor is suitable for miniature manufacturing because it has a high discharge per cycle and a simple structure, while also being widely used as lubrication oil of engines and the hydraulic source of automatic transmission. In the automobile industry, it has been necessary to continuously improve the flow rate and noise of internal gear pumps for better fuel efficiency through optimal gerotor design. In this study, to obtain an optimal gerotor with an ellipse-elliptical involute-ellipse combined lobe shape, an automatic program was developed for calculating performance parameters and drawing a gerotor profile. An oil pump was assembled with the optimal gerotor together with the port used at the actual field and CFD analysis was performed on this assembly using Ansys-CFX. A performance test for the oil pump was carried out and showed good agreement with the results obtained from the theoretical analysis and the CFD analysis.

• Earthquakes and Structures
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• 제7권5호
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• pp.719-733
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• 2014

The equivalent frame method (EFM) is widely used for the design of two-way reinforced concrete slab structures, and current design codes of practice permit the application of the EFM in analyzing the flat plate slab structures under gravity and lateral loads. The EFM was, however, originally developed for the flat plate structures subjected to gravity load, which is not suitable for lateral loading case. Therefore, this study, the first part of series research paper, proposed the structural analysis method for the flat plate slab structures under the combined gravity and lateral loads, which is named as the unified equivalent frame method (UEFM). In the proposed method, some portion of rotation induced in the torsional member is distributed to the flexibility of the equivalent columns, and the remaining portion is contributed to that of the equivalent slabs. In the consecutive companion paper, the proposed UEFM is verified by comparing with test results of multi-span flat plate structures. Also, a simplified nonlinear push-over analysis method is proposed, and verified by comparing to test results.

• Journal of Pharmaceutical Investigation
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• 제23권4호
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• pp.217-223
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• 1993

The combined products of antacid and anti-ulcer agent were prepared with antacid composed of aluminium hydroxide dried gel, magnesium hydroxide and simethicone with a ratio of 1:1:0.1 (M) and anti-ulcer agent, aceglutamide aluminium (AGA). The efficacy of antacid was evaluated in vitro with Fuchs, Johnson-Duncan and Rosset-Rice methods and in vivo using an aspiration method in rat. The addition of anti-ulcer agent did not affect the neutralizing capacity of M significantly. The combined products with the M/AGA ratios of 2.3:1 and 3.4:1 produced the maximum pH of $4.0{\sim}5.8$ and the duration time of $64{\sim}137$ min in vitro test. The in vivo neutralizing test in rats showed the rapid increase of gastric pH up to 3.5 within 30 min and the gastric pH of $4{\sim}6$ was kept for 5 hr.

• Journal of Information Processing Systems
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• 제14권1호
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• pp.191-204
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• 2018

To combat the adverse impact imposed by illumination variation in the face recognition process, an effective and feasible algorithm is proposed in this paper. Firstly, an enhanced local texture feature is presented by applying the central symmetric encode principle on the fused component images acquired from the wavelet decomposition. Then the proposed local texture features are combined with Deep Belief Network (DBN) to gain robust deep features of face images under severe illumination conditions. Abundant experiments with different test schemes are conducted on both CMU-PIE and Extended Yale-B databases which contain face images under various illumination condition. Compared with the DBN, LBP combined with DBN and CSLBP combined with DBN, our proposed method achieves the most satisfying recognition rate regardless of the database used, the test scheme adopted or the illumination condition encountered, especially for the face recognition under severe illumination variation.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.804-809
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• 2008

In this study, the cooling performance of a C/C composite material structure with metallic cooling tubes fixed by elastic force without chemical bonding was evaluated experimentally using combustion gas in a rocket combustor. The C/C composite chamber was covered by a stainless steel outer shell to maintain its airtightness. Gaseous hydrogen as a fuel and gaseous oxygen as an oxidizer were used for the heating test. The surface of these C/C composites was maintained below 1500 K when the combustion gas temperature was about 2900 K and heat flux to the combustion chamber wall was about 9 $MW/m^2$. No thermal damage was observed on the stainless steel tubes which were in contact with the C/C composite materials. Results of the heating test showed that such a metallic-tube-cooled C/C composite structure is able to control the surface temperature as a cooling structure(also as a heat exchanger), as well as indicating the possibility of reducing the amount of the coolant even if the thermal load to the engine is high. Thus, application of the metallic-tube-cooled C/C composite structure to reusable engines such as a rocket-ramjet combined cycle engine is expected.

• PNF and Movement
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• 제19권3호
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• pp.441-449
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• 2021

Purpose: The purpose of this study was to investigate the effect of strength training combined with blood flow restriction on leg muscle thickness in children with cerebral palsy. Methods: Nineteen children with cerebral palsy, aged between five and 10 years of age, living in area N, were recruited. Ten participants were classified into a blood flow restriction group and nine into a strength exercise group. The experimental group performed strength training using a blood flow restriction cuff on the leg, and the control group performed strength training without blood flow restriction. A paired t-test was performed to confirm intragroup changes before and after five weeks of the experiment, and an independent t-test was performed to confirm intergroup changes, and the significance level was α=0.05. Results: The rectus femoris, gastrocnemius and gluteus medius muscles showed significant differences in the groups after five weeks (p<0.05). There was a significant difference between the groups in the rectus femoris and gastrocnemius after five weeks (p<0.05). Conclusion: As a result of this study, it was found that strength training combined with blood flow restriction had a positive effect on the changes in leg muscle thickness in children with cerebral palsy. This suggests the possibility of using it in the future as basic data for strength training methods and blood flow restriction exercises for children with cerebral palsy.

• Corrosion Science and Technology
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• 제13권6호
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• pp.214-223
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• 2014

Interest in the durability assessment and structural performance has increased according to an increase of concrete structures in salt damage environment recent years. Reliable way ensuring the most accelerated corrosion test is a method of performing the rebar corrosion monitoring as exposed directly to the marine test site exposure. However, long-term exposure test has a disadvantage because of a long period of time. Therefore, many studies on reinforced concrete in salt damage environments have been developed as alternatives to replace this. However, accelerated corrosion test is appropriate to evaluate the critical chlorine concentration in the short term, but only accelerated test method, is not easy to get correct answer. Accuracy of correlation acceleration test depends on the period of the degree of exposure environments. Therefore, in this study, depending on the concrete mix material, by the test was performed on the basis of the composite degradation of the salt damage, and investigate the difference of corrosion initiation time of the rebar, and indoor corrosion time of the structure, of the marine environment of the actual environments were inuestigated. The correlation coefficient was derived in the experiment. Long-term exposure test was actually conducted in consideration of the exposure conditions submerged zone, splash zone and tidal zone. The accelerated corrosion tests were carried out by immersion conditions, and by the combined deterioration due to the carbonation and accelerated corrosion due to wet and dry condition.

• Journal of Mechanical Science and Technology
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• 제17권3호
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• pp.400-408
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• 2003

A study on the progressive inelastic deformation behavior of the 316 L stainless steel cylindrical structure with plate-to-shell junction under moving temperature front was carried out by structural test and analysis. The structural test intends to simulate the thermal ratcheting behavior occurring at the reactor baffle of the liquid metal reactor as free surface of hot sodium pool moves up and down under plant transients. The thermal ratchet load that heats the specimen up to 550$^{\circ}C$ was applied repeatedly and residual deformation was measured. The thermal ratcheting test was carried out with two types of cylindrical structures, one with plate to-shell junction and the other without the junction to investigate the effects of the geometric discontinuities on the global ratcheting deformation. The temperature distributions of the test specimens were measured and were used for the ratcheting analysis. The ratchet deformations were analyzed with the constitutive equation of the non-linear combined hardening model. The analysis results were in good agreement with those of the structural tests.

• 한국자동차공학회논문집
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• 제19권4호
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• pp.107-113
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• 2011

Coolant rubber hoses for automotive radiators under thermal and mechanical loadings can be degraded and thus failed due to the influences of the locally formed electricity. In this study, an advanced test method was developed to simulate the failure problem of the rubber hose. For carbon black filled EPDM (ethylene-propylene dine monomer) rubber used as a radiator hose material the ageing behaviors by the electro-chemical stresses combined with a tensile strain were analyzed. As the tensile strain increased, the current of the rubber specimen reduced indicating an increase of the internal defects and electrical resistance of the rubber specimen. Elongation at break and IRHD hardness rapidly decreased with increasing the ageing time. Both electro-chemical stress and mechanical tensile stress clearly accelerated the degradation of EPDM rubber.

• 한국지하수토양환경학회지:지하수토양환경
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• 제15권5호
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• pp.8-15
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• 2010

The purpose of this research is to check the validation of an auto-analysis method combined with aqua regia digestion apparatus for improvement of water distillation method used as a fluorine test of soil. Fluorine contents of CaO used in the pretreatment course of water distillation method were 120 mg/kg ~ 5,064 mg/kg at the blank test, which was exceeded up to maximum 12.5 times of the soil standard, so it was estimated due to a effect of fluorine existing as impurities of CaO. The recovery test of the same samples indicated that water distillation method and auto-analysis method were 134.5mg/kg and 161.7mg/kg respectively, the recovery ratio of the latter was 16.8% higher than the formal. The validation test of two methods satisfied the standard, but auto analysis method was excellent more than distillation method. Also, auto analysis method could save a analysis time up to maximum 4.7 times by comparison with water distillation method.