• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.1
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• pp.39-46
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• 1985

Heading time was hastened by the combination of seeding time and longday treatment in order to elucidate the effect of early heading on earliness in maturity, vegetative growth and grain yield in five barley varieties and four wheat varieties under field conditions in Suwon, Korea, 1978-79. About 15 days of earliness in heading accelerated only 2 to 6 days in maturity. Furthermore, the duration of grain fill was not much prolonged comparing with the extension of days from heading to maturity, because of the extension of periods from heading to anthesis at lower temperature resulting in somewhat greater final grain weight. Periods from heading to anthesis and from anthesis to maturity were negatively correlated with the air temperature. In early heading, leaf area at 10 days after anthesis and net assimilation rate were much limited, and although leaf area duration got larger, presumably, it could not make up for the reduction of grain yield. Grain yield per plant reduced noticeably in early heading. This was mainly caused by the reduction of spike number and grain number per spike.

• Journal of Sensor Science and Technology
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• v.15 no.1
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• pp.58-64
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• 2006

In this study, we describe a low-temperature wafer-level thermocompression bonding using electroplated gold seal line and bonding pads by electroplating method for RF-MEMS devices. Silicon wafers, electroplated with gold (Au), were completely bonded at $320^{\circ}C$ for 30 min at a pressure of 2.5 MPa. The through-hole interconnection between the packaged devices and external terminal did not need metal filling process and was made by gold films deposited on the sidewall of the throughhole. This process was low-cost and short in duration. Helium leak rate, which is measured to evaluate the reliability of bonded wafers, was $2.7{\pm}0.614{\times}10^{-10}Pam^{3}/s$. The insertion loss of the CPW packaged was $-0.069{\sim}-0.085\;dB$. The difference of the insertion loss between the unpackaged and packaged CPW was less than -0.03. These values show very good RF characteristics of the packaging. Therefore, gold thermocompression bonding can be applied to high quality hermetic wafer level packaging of RF-MEMS devices.

• Journal of Korean society of Dental Hygiene
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• v.16 no.1
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• pp.103-109
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• 2016

Objectives: The purpose of the study is to investigate the effect of oral exercise on oral health and oral health related quality of life in the elderly people. Methods: The subjects were83 elderly people including 42 elderly people of intervention group and 41 elderly people of control group. A dentist and a dental hygienist carried out the direct oral examination. The self-reported questionnaire was completed and the oral examination consisted of decayed tooth, missing tooth, filling tooth, functioning tooth, plaque index, salivary flow rate, and range of motion in mouth opening. OHIP-14 was used to assess the oral health related quality of life. For three months, oral exercise was done twice per week in the experimental group. Results: Before oral exercise, there was no significant difference between the intervention group and control group. After 3 months, there was a significant improvement in plaque reduction and range of motion in mouth opening between two groups (p<0.001, p<0.001). Oral health related quality of life was observed in the intervention group (p<0.001). Conclusions: The oral exercise using toothbrushing remarkably improved the oral health related quality of life in the elderly people.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.4
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• pp.89-98
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• 2007

The purpose of this study is to experimentally evaluate the structural behavior of built-up type column consisted of angles and y-shape steel sheet forms for filling concrete. This column for minimizing form working and reinforcement placing is able to improve capacity of construction and reduce the term of works. Thirteen 1/3 scaled columns were fabricated. The main variables are 1) effect of angles and y-shape steel sheets of fabricated columns, 2) slenderness of column, 3) eccentricity of column. The results show that the experimental capacity of built-up type column is similar to theoretical one by reinforcement concrete design code. The maximum loads increase according to the rate of angle to cross section of column.

• Bulletin of the Korean Chemical Society
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• v.29 no.4
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• pp.749-754
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• 2008

To increase the solubility of sibutramine freebase, the solid dispersion was prepared using a fluid-bed granulator. The solid dispersion containing sibutramine freebase was characterized by differential scanning calorimetry (DSC) and powder X-ray diffraction (XRD). After filling the sibutramine solid dispersion in the gelatin hard capsule, we performed in vitro dissolution test, the stability test under accelerated conditions and pharmacokinetic study in beagle dogs. The DSC and XRD data showed that sibutramine solid dispersion would be amorphous state. The dissolution rate of sibutramine solid dispersion was significantly increased about 70% than sibutramine freebase. The stability of sibutramine solid dispersion capsules was equivalent or above to commercial product of sibutramine. In beagle dogs, the sibutramine solid dispersion showed equivalent pharmacokinetic behavior with commercial product of sibutramine hydrochloride. In conclusion, the solid dispersion system provided a possible way to overcome the low solubility of sibutramine freebase, and the sibutramine solid dispersion can be a bioequivalent with the commercial product in humans.

• Journal of Periodontal and Implant Science
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• v.45 no.1
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• pp.23-29
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• 2015

Purpose: This study was conducted to compare the cumulative survival rates (CSRs) and the incidence of postloading complications (PLCs) between a bone-level internal connection system (ICS-BL) and an external connection system (ECS). Methods: The medical records of patients treated with either a ICS-BL or ECS between 2007 and 2010 at Asan Medical Center were reviewed. PLCs were divided into two categories: biological and technical. Biological complications included >4 mm of probing pocket depth, thread exposure in radiographs, and soft tissue complications, whereas technical complications included chipping of the veneering material, fracture of the implant, fracture of the crown, loosening or fracture of the abutment or screw, loss of retention, and loss of access hole filling material. CSRs were determined by a life-table analysis and compared using the log-rank chi-square test. The incidence of PLC was compared with the Pearson chi-squared test. Results: A total of 2,651 implants in 1,074 patients (1,167 ICS-BLs in 551 patients and 1,484 ECSs in 523 patients) were analyzed. The average observation periods were 3.4 years for the ICS-BLs and 3.1 years for the ECSs. The six-year CSR of all implants was 96.1% (94.9% for the ICS-BLs and 97.1% for the ECSs, P=0.619). Soft tissue complications were more frequent with the ECSs (P=0.005) and loosening or fracture of the abutment or screw occurred more frequently with the ICS-BLs (P<0.001). Conclusions: Within the limitations of this study, the ICS-BL was more prone to technical complications while the ECS was more vulnerable to biological complications.

• Applied Microscopy
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• v.29 no.1
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• pp.67-73
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• 1999

It is practically hard to prepare good TEM specimens from powders which are embedded in epoxy materials for ion milling, because the milling rate difference between powders and epoxy is quite large. In order to overcome this problem, we tried to find methods to increase the density of powders in the embedding epoxy without loosing the adhesive strength between them. Powder density was considerably increased by employing a centrifuge for embedding, compared to the result by a conventional vacuum embedding. In addition, mixing powders of different sizes after sieving also enhanced the final density by allowing smaller particles filling in the gaps of larger particles. Ion milling of powders embedded by these methods resulted in thin specimens good enough for normal TEM works. TEM specimens from spherical, platy and fibrous powders of submicron size were successfully prepared by this centrifuging method.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.5
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• pp.361-368
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• 2003

The responses of five varieties and three cultivars of pea (Pisum sativum) to Rhizobium inoculation on nodulation, growth, nitrogenase activity, dry matter production and N uptake were investigated. The pea varieties were IPSA Motorshuti-l, IPSA Motorshuti-2, IPSA Motorshuti-3, BARI Motorshuti-l, BARI Motorshuti-2 and the cultivars were 063, Local small and Local white. Fifty percent seeds of each pea variety/cultivar were inoculated with a mixture of Rhizobium inoculants at rate of 15g/kg seed and the remaining fifty percent seeds were kept uninoculated. The plants inoculated with Rhizobium inoculant significantly increased nodulation, growth, nitrogenase activity, dry matter production and N uptake. Among the varieties/cultivars, BARI Motorshuti-l performed best in almost all parameters including nitrogenase activity of root nodule bacteria of the crop. There were positive correlations among the number and dry weight of nodules (r=$0.987^{**}$, $0.909^{**}$), nitrogenase activity of root nodule bacteria (r=$0.944^{**}$, $0.882^{**}$), dry weight of shoot (r=$0.787^{**}$, $0.952^{**}$), N content (r=$0.594^{**}$, $0.605^{**}$) and N uptake (r=$0.784^{**}$, $0.922^{**}$) by shoot both at flowering and pod filling stages of the crop, respectively. It was concluded that BARI Motorshuti-l in symbiotic association with Rhizobium inoculant performed best in recording nitrogenase activity, dry matter production and N uptake by pea.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.137-142
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• 2008

Ignition characteristics of combustion chamber with LOx lead cyclogram for liquid rocket engine were described. The combustion chamber has chamber pressure of 60 bar, propellant mass flow rate of 89 kg/s, and nozzle expansion of 12. Cold flow test to determine the filling time of propellant for cyclogram with LOx lead supply, ignition test to check the ability to ignite starting fuel from the ignitor, low pressure combustion test to check the propagation of flame into main fuel-oxidizer mixture from starting fuel and the main combustion stage, and design point combustion test to check the combustion performance were performed. Ignition and combustion tests with LOx lead supply were successfully performed and the stable cyclogram of start sequence for combustion chamber was developed.

• Journal of Fisheries and Marine Sciences Education
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• v.16 no.2
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• pp.257-270
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• 2004

The two-phase closed thermosyphon is a heat transfer device capable of transfer large quantities of heat from a source to a sink by taking advantage of the high heat transfer rates associated with the evaporation and condensation of a working fluid within the device. A study was carried out with the performance of the heat transfer of the thermosyphon having 50, 60, 70, 80, 90 internal micro grooves in which boiling and condensation occur. A plain thermosyphon having the same inner and outer diameter as the grooved thermosyphon is also tested for comparison. Water, methanol and ethanol have been used as the working fluids. The liquid filling as the ratio of working fluid volume to total volume of thermosyphon, the inclination angle, micro grooves and operating temperature have been used as the experimental parameters. The heat flux and the boiling and the condensation heat transfer coefficient and overall heat transfer coefficient at the condenser and evaporator zone are estimated from the experimental results. The experimental results have been assessed and compared with existing correlations. Imura's and Kusuda's correlation for boiling showed in good agreement with experimental results within ${\pm}20$％ in plain thermosyphon. The maximum heat transfer rate was obtained when the liquid fill ratio was about 25%. The high heat transfer coefficient was found between 25o and 30o of inclination angle for water and between 20o and 25o for methanol and ethanol. The relatively high rates of heat transfer have been achieved in the thermosyphon with internal micro grooves. The micro grooved thermosyphon having 60 grooves shows the best heat transfer coefficient in both condensation and boiling. The maximum enhancement (i.e. the ratio of the heat transfer coefficients of the micro grooved thermosyphon to plain thermosyphon) is 2.5 for condensation and 2.3 for boiling.