• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.3
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• pp.51-59
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• 2012

Through this research safety factors were analyzed for concrete precast panels in road pavement which happens in lifting, moving, and installing. Two half size of full-scale precast concrete panels were made while one full-scale precast concrete panel was made. A series of strain gages for concrete and steel were installed and measured in lifting and transporting. Measurement results indicate that in case of 60 degree of lifting, small scale panel in dynamic motion produces about 3.54 times of strain compared to the static condition. However strain measurement of full-scale concrete panel in lifting and transportation does not yield any big difference compared to the small scale panels in the static condition. From this experimental results safety of the full-scale concrete panel was attained for the lifting system adopted in this research.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1913-1916
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• 2008

Electrohydrodynamic (EHD) printing has gained significant interest after a direct writing with a resolution of a few tens nanometer was demonstrated using EHD. Basically, EHD use the electric field to generate droplet which is much smaller than nozzle diameter, so that high resolution printing is possible and the clogging problem can be alleviated as well. However, to adapt this technology to the real application, the fundamental studies are necessary to stabilize EHD jetting, to maximize jetting frequency, and to optimize the design of multi EHD nozzle, etc. In this study, by imaging EHD jetting using high speed camera and measuring the current, the effect of electric field intensity and back pressure on jetting frequency and jetting diameter were studied.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1095-1098
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• 2005

본 논문은 IPS 구축에 있어서 핵심적인 역할을 수행하는 운영체제를 위해 최근 각광을 받고 있는 Embedded Linux Kernel 의 성능을 테스트하기 위한 환경을 구축한다. Benchmarking tool 인 UnixBench 프로그램을 사용하여 성능을 테스트 한다. 또한 standard kernel 의 성능 테스트도 같이 포함하여 종합적으로 성능 결과를 비교 분석한다. 이런 실험 결과를 통해서 IPS 시스템에 적합한 임베디드 리눅스 운영체제 결정을 하고자 한다.

• Journal of the Korea Concrete Institute
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• v.28 no.2
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• pp.129-139
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• 2016

Cast-in-place concrete-filled hollow PC (HPC) columns are used to reduce lifting load of heavy-weight PC columns and to improve the structural integrity of joints. In the present study, a new type of HPC column was proposed to improve the productivity and structural integrity of the concrete. To form the hollow PC columns, a permanent inner form was prefabricated using structural deck plates and penetrated lateral bars. Half-scale specimens of four HPC columns were tested under combined axial compression and lateral cyclic loading to evaluate the seismic resistance. In the design of test specimens, various parameters such as the spacing of lateral re-bars, the use of steel fiber, and the thickness of PC cover were considered. The test results showed that the proposed HPC columns generally exhibited satisfactory load-carrying capacity and deformation capacity without brittle failure of PC. If closely spaced hoops or fiber reinforcements are used for PC, the deformation capacity can be improved further by restraining PC spalling.

• Applied Biological Chemistry
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• v.23 no.3
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• pp.184-188
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• 1980

A survey of pesticide and copper residues of the citrus orchard soil was conducted during October 1979-June 1980 in Jeju, Seogwipo county. The citrus orchards were classified into five groups according to different cultivated period; 5 year orchard, 10 year orchard, 15 year orchard, 20 year orchard, and 30 year orchard. Each of the above samples was divided again to three layers of soil depth; the surface layer$(0{\sim}10cm)$, the middle layer $(10{\sim}20cm)$, and the bottom layer $(20{\sim}40cm)$. In this experiments, Kelthane and Akar, as well as copper residues were detected in all soil samples. Residue levels of above chemicals were increased in soils of orchard with longer cultivation periods, and at the same time, decreased with soil depth. The residues of those ranged as follows; a) from trace to 1.359ppm in Kelthane, b) from trace to 0.925ppm in Akar, and c) from trace to 40.734ppm in copper. It is noted that the average residues of Kelthane was 0.251ppm, Akar, 0.120ppm, and that of copper was 2.168ppm, respectively.

• Journal of the Korea Concrete Institute
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• v.26 no.1
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• pp.35-46
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• 2014

Two types of cast-in-place concrete-filled hollow PC (HPC1, HPC2) columns were developed to reduce lifting load of heavy-weight PC columns and to improve the structural integrity of joints. To form the hollow PC columns, a couple of prefabricated PC panels was used for HPC1, and special hoops were used for HPC2. Lateral pressure of wet concrete on PC faces was measured while placing the concrete inside the columns. To evaluate the seismic resistance, full scale specimens of two HPC columns and a conventional RC column were tested under combined axial compression and lateral cyclic loading. The test results showed that the structural performance of the proposed HPC columns such as intial stiffness, maximum strength, and displacement ductility was comparable to that of the conventional RC column, but the energy dissipation of HPC2 slightly decreased after rebar-buckling. However, all the test specimens satisfied the energy dissipation requirement specified in ACI 374.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.8
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• pp.619-626
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• 2009

The objective of this study was to evaluate the efficiency of Fe and Mn oxides coated granular activated carbons (FMOCGs) for the removal of arsenite and arsenate by oxidation and adsorption mechanisms using surface characterization and batch adsorption experiments. Within four manufactured adsorbents, Fe and Mn contents of FMOCG-1 was the highest (178.12 mg Fe/g and 11.25 mg Mn/g). In kinetic results, As(III) was removed by oxidation and adsorption with FMOCGs. Removal of arsenic by FMOCGs increased as pH value of the solution decreased. The adsorption isotherm results were well fitted with Langmuir isotherm. Adsorption amount of As(V) onto FMOCGs was higher than that of As(III) and the maximum adsorption capacities of FMOCGs for As(III) and As(V) were 1.38~8.44 mg/g and 2.91~9.63 mg/g, respectively.

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.733-738
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• 2013

Sediment contains a high fraction of organic matter, high buffering capacity, and a large portion of fine grained particles such as silt and clay, which are major barriers to remove heavy metals from sediments. In this study, a lab-scale electrokinetic (EK) technique was applied to remove heavy metals effectively from marine sediment at a constant voltage gradient of 2 V/cm. A concentration of 0.1 M of ethylenediaminetetraacetic acid (EDTA), citric acid (CA), $HNO_3$, and HCl were circulated in the cathode, and tap water was circulated in the anode. CA extracted 92.4% of Ni, 96.1% of Cu, 97.1% of Zn, and 88.1% of Pb from marine sediment. A higher voltage gradient enhanced the transport of citrate and EDTA into the sediment and, therefore, increased metal extraction from the marine sediment through a complexation reaction between metals and the chelates. Based on these results, the electrokinetic process using a high voltage gradient with EDTA and CA might be useful to extract heavy metals from marine sediment.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06b
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• pp.33-36
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• 2011

본 논문에서는 SMART(Self-Monitoring Analysis and Reporting Technology)를 기반으로 SSD(Solid State Drives) 저장 장치의 신뢰성을 분석할 수 있는 방법론과 도구를 제안한다. 방법론은 SSD를 구성하는 플래시 메모리의 결함 종류, 결함들을 효과적으로 모니터링 할 수 있는 SMART 속성과 임계값, 그리고 이를 기반으로 SSD의 신뢰성을 예측할 수 있는 모델로 구성된다. 이 방법론은 신뢰성 분석 도구로 구현 되었으며, 이 도구는 Workload generator, SMART monitor, Dependability analyzer, 그리고 GUI viewer로 구성된다. 실제 두 회사에서 생산한 6개의 SSD를 이용하여 실험한 결과, SMART를 기반으로 SSD의 고장 예측이 가능하며, 여러 속성들을 동시에 고려하였을 때 예측의 정확도가 높아짐을 발견하였다.

• Biomolecules & Therapeutics
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• v.4 no.2
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• pp.111-121
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• 1996

Antiulcer effects of Artemisia herba extract (DA-9601) were evaluated in various types of experimental gastric ulcer induced in rats. And the effects of DA-9601 on mucus, basal and stimulated gastric acid secretion were also investigated in rats. DA-9601 (12.5∼400 mg/kg, p.o.) prevented the formation of gastric ulcers induced by 60% EtOH in 150 mM HC1, restraint water immersion stress, platelet activating factor (PAF), aspirin in 150 mM HCI with Pylorus-ligation and indomethacin. DA-9601 (4∼400 mg/kg, p.o.) significantly accelerated the healing rate of acetic acid-induced gastric ulcer and significantly stimulated mucus secretion in a dose-dependent manner. DA-9601 (20∼200 mg/kg, i.d.), however, did not inhibit basal gastric acid secretion in pylorus ligated rats and DA-9601 (200 mg/kg, i.d.) failed to influence histamine-, pentagastrin- and carbachol- stimulated gastric acid secretion. These results suggest that DA-9601 has inhibitory action on gastric lesion and ulceration through increasing mucus secretion in the stomach of rats without influencing basal and stimulated gastric acid secretion.