• Journal of Welding and Joining
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• v.32 no.1
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• pp.102-107
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• 2014

SCR(Thyristor) type $CO_2$ welders have widely used for the welding process of heavy industries such as shipbuilding and plant. Since the industrial fields of shipbuilding and plant are usually exposed to severe welding condition with lots of dust, extreme temperature, high humidity and vibration, it is not recommended to use inverter type welder despite its state-of-the-art technology. Many sophisticated functions in the inverter welder may not work due to malfunction of its sensitive components. Hence this study focused on digitalization of SCR $CO_2$ welder by making use of microprocessor for SCR phase control. By this application, fine control of output of the $CO_2$ welding systems is achieved. Also pulse output mode of operation is realized and its verification is carried out with aluminum sample welding. The experimental results showed sound weld bead. The front operation panel provide user with numerical parameter settings and monitors. It will help precise weld process monitoring and control with digital value.

• Journal of Welding and Joining
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• v.25 no.4
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• pp.42-48
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• 2007

An inert gas atomized NiTiZrSiSn bulk metallic glass feedstock was sprayed onto the copper plate using vacuum plasma spraying process. In order to change the in-flight particle energy, that is, thermal energy, the hydrogen gas flow rate in plasma gas mixture was increased at the constant flow rate of argon gas. Coating and single pass spraying bead were produced with the least feeding rate. Regardless of the plasma gas composition, fully melted through unmelted particle could be observed on the overlay coating. However, the frequency of the unmelted particle number density was increased with the decrease of the hydrogen gas flow rate. The amorphous phase fraction within coating was also affected by the number density of the unmelted particle.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.3
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• pp.256-267
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• 2019

Styrofoam beads, which are relatively inexpensive and can provide a large specific surface area, were tested as filter media. Styrofoam beads with a diameter of $3{\pm}0.5mm$ were used; the specific surface area of the beads was $1,034m^2{\cdot}m^{-3}$. Five independent recirculating culture systems were used in the experiment. Each system consisted of one culture tank and three trickling bio-filters. Using the systems, nitrification efficiency was evaluated with respect to hydraulic loading rate (HLR) and carbon/nitrogen (C/N) ratio. The lowest ammonia and nitrogen concentrations were $0.84mg{\cdot}L^{-1}$ and $1.30mg{\cdot}L^{-1}$, respectively, observed at an HLR of $50.9m^3{\cdot}m^{-2}{\cdot}h^{-1}$. Nitrification efficiency in the culture tank was highest at a C/N ratio of 0, with ammonia and nitrite nitrogen concentrations of $0.32mg{\cdot}L^{-1}$ and $0.90mg{\cdot}L^{-1}$, respectively. Ammonia and nitrite nitrogen concentrations in the culture tank abruptly changed at C/N ratios ${\geq}3$.

• International Journal of Korean Welding Society
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• v.3 no.1
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• pp.34-38
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• 2003

It has been used many kinds of horizontal butt-welding methods at block-to-block erection stage in shipbuilding companies. For examples, some companies use conventional FCAW process with one side or both sides groove joint welding, others use carriage with torch holder type mechanized welding method. Although lots of efforts were done until now, some problems in quality and productivity still remain in ship's hull welding. In this study, we have attempted to raise productivity and quality on horizontal position of welding with following 3 items. 1) Prepare groove condition with no root gap for making easy fit-up work. 2) Develop improved MAG (100% $CO_2$ gas shielding) welding process with solid wire for making sound root bead from one side. 3) Develop and apply quite new automatic welding carriage. The stability of new welding process was confirmed by conducting mechanical tests of weldments to verify the soundness of weldments.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.1
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• pp.181-188
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• 2004

Monovision is defined as correcting one eye for distance vision and the other eye for near vision. Single-vision contact lenses are used for each eye. The patient selectively suppresses one eye while using the other eye. This study was performed to measure binocular function and patient satisfaction with monovision induced by adding +3.00D to spectacle prescription for distance vision in nonpresbyopic students. This study comprised 144 nonpresbyopic students with monovision induced by adding +3.00D to spectacle prescription. Monovision was induced by undercorrecting the nondominant eye by adding 3.00 diopters for near vision and correcting the dominant eye with emmetropia for distance vision. For research of the binocular function on Monovision. This study was tested the obstacle course, water pouring test, catching and throwing, bead classification including the stereopsis test. These tests were comparative to the normal binocular state. As a results, the stereopsis have a significant reductions in Monovision. There was no significantly difference between monovision group and control group in monovision exercise (obstacle course, water pouring test, catching and throwing, and bead sorting) at near and distance. This study indicates that monovision is an effective and reasonable therapeutic modality for correcting presbyopia. By the application of above methods, this study could be used the student for the practical practice and understand on the Monovison.

• Journal of the Korean Magnetics Society
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• v.25 no.5
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• pp.162-168
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• 2015

The ${\mu}$-turn coil having a width of ${\mu}m$ on the GMR-SV (giant magnetoresistance-spin valve) device based on the antiferromagnetic IrMn layer was fabricated by using the optical lithography process. In the case of GMR-SV film and GMR-SV device, the magnetoresistance ratios and the magnetic sensitivities are 4.4%, 2.0%/Oe and 1.6 %, 0.1%/Oe, respectively. In the y-z plane the distribution of magnetic field of GMR-SV device and $10{\mu}$-turns coil which put under the several magnetic bead(MB)s with a diameter of $1{\mu}m$ attached to RBC (red blood cell) was analyzed by the computer simulation using the finite element method. When the AC currents of 20 kHz from 0.1 mA to 10.0 mA flow to the 10 turns ${\mu}$-coil, the magnetic field at the position of $z=0{\mu}m$ at the center of coil was calculated from $30.1{\mu}T$ to $3060{\mu}T$ in proportion to the current. The magnetic field at the position of $z=10{\mu}m$ was decreased to one-sixth of that of $z=0{\mu}m$. It was confirmed that the $10{\mu}$-turn coil having enough magnitude of magnetic field for the capture of RBC is possible to use as a biosensor for the detection of magnetic beads attached to RBC.

• Korean Journal of Veterinary Research
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• v.43 no.2
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• pp.203-210
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• 2003

The purpose of this study is to investigate the pharmacokinetics and tissue distribution of recombinant bovine somatotropin (rBST) after subcutaneous adminstration of $^{125}I-rBST$ in male and female rats. A solid state conjugation (Iodo-bead$^{(R)}$) method was confirmed useful for producing $^{125}I-rBST$ because the administration of the conjugated form enabled enough to determine time- concentration relationships of rBST in rats. Subcuatenous administrations showed sex differences that female ($t_{1/2,kc}$, 2.87 h) revealed rapid elimination as compared to male ($t_{1/2,ke}$, 4.81 h), with the absorption ($t_{1/2,ka}$ in male being 0.3 h and that in female 0.75 h) in the reverse order. For subcutaneous administration of rBST in male rats, the liver was the highest in amount, followed by kidney, testes, muscle, and stomach, at the slaughtering tame of 1, 6, 12 and 24 h. But the testes was the highest at the 48 h slaughtered animals, followed by liver, kidney, stomach, and muscle. In slaughtered females at 1, 6, and 12 h after the administration of rBST, the liver was the highest, followed by ovary, kidney, small intestine, and stomach. At 24 and 48 h slaughtered female rats, the ovary was the highest, the liver the second, and the kidney the third.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.207-217
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• 1992

In this study, isolated and cultured nitrogen fixed microbes were seeded in the three-phase fluidized bed in which gas, solid and liquid were contacted directly. Input velocity was varied from 8.12 cm/hr to 16.32 cm/hr. And upflow gas pressure was fixed to 80 psi. Return ratios were from 0.2 to 0.6 with the each experimental condition. According to these condition, movement of media, growth of biofilm and removal efficiency were measured. As the results, in case of briquette ash, biofilm was developed to $170{\mu}m$ when velocity was 8.12 cm/hr and return ratio was 0.6. In this condition, COD removal efficiency was 97% and $NH_4$-N removal efficiency was 83%. At the same condition, biofilm thickness of glass bead was $17.59{\mu}m$ and its COD and $NH_4$-N removal efficiency was 83% and 72%. Nitrogen fixed microbes have following characters: it formed dark-brownish sludge, excellent adhesive force, easy solid-liquid separation and low oxygen uptake ratio, but sensitive to DO concentration. Not only it endured shock loading, but required short time to steady state.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.661-667
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• 2002

Welding-induced buckling distortion is one of the most problematic concerns in both design and fabrication of welded thin-plate structures. This paper deals with experimental and numerical results of the welding-induced longitudinal and/or buckling distortion occurring in welding of 6mm-thick AH36 high strength steel plates. Effects of the heat input and the plate size on the distortion were experimentally evaluated for square plates. Bead-on-plate welding was performed with the submerged arc welding process along the middle line of plate specimens. Experimental results showed that the longitudinal distortion made a single curvature in the plate, and the distortion magnitude along the weld centerline was proportional to the heat input and the plate size. The experimental results were used to examine the validity of the numerical simulation procedure for welding-induced distortion where the longitudinal distortion mode and magnitude were numerically quantified. Three-dimensional, large deformation, welding simulations were performed for selected weld models. Numerical results of the distortion mode and magnitude were in a good agreement with experimental ones. Depending on the presence of halting the distortion growth during the cooling cycle of welding, the condition discriminating buckling distortion from longitudinal distortion was established. Eigenvalue analyses were performed to check the buckling instability of tested plates with different sizes subjected to different heat inputs. The perturbation load pattern for the analysis was extracted from longitudinal inherent strain distributions. Critical buckling curve from the eigenvalue analyses revealed that the buckling instability is manifested when plate size or heat input increases.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.2
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• pp.775-781
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• 2015

Background: RB1 (retinoblastoma 1) was reportedly one of the major determinative factors for sensitivity to taxanes in previous studies. In this study, we investigated the influence of RB1 single nucleotide polymorphisms (SNPs) on the efficacy of platinum-taxane regimens in advanced NSCLC patients. Materials and Methods: 234 cases of patients with advanced NSCLC who were treated with first-line platinum-taxane agents were enrolled in this study. Genomic DNA was extracted from patients' peripheral blood samples using a QIAamp DNA Maxi Kit, and genotyped by iSelect HD Bead-Chip. Results: Regression analyses were conducted through the univariate and multivariate Cox proportional hazards model in the 234 patients. The results showed that of the eight RB1 tagSNPs, only rs4151510 was a positive predictive factor for the advanced NSCLC patients treated with platinum taxanes regimen. The patients with G/G genotype of RB rs4151510 had longer overall survival (OS) than the non-G/G genotype (p=0.018). The histology was also correlated with OS in the whole advanced NSCLC patients. Three tagSNPs of RB1, rs4151510, rs4151465, rs9568036 were significantly associated with OS in the advanced NSCLC patients with squamous cell histology using Kaplan-Meier overall survival analysis stratified by histology. Conclusions: RB1 genomic variants were correlated with the efficacy of platinum-taxanes regimen. RB rs4151510 is an independent factor of the prognosis of NSCLC patients receiving platinum-taxane chemotherapy.