• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2016.10a
• /
• pp.115-116
• /
• 2016

This study applied BS replacement mortar's ERCO to see what impact it has on moisture evaporation and contraction changes, and resulted in the following. Depending on the rate of change in length according to the cure method of BS replacement mortar, high-strength areas were shown to have a bigger increase in the rate of change in length than regular or low-strength areas, and differences in rate of change in length due to ERCO cure methods were shown to be slight. For rate of changes in mass, on the whole there was an increase in the order of dry curing, cover curing, 7-day water curing, and28-day water curing. A comprehensive view says that after removal of test piece specimens, ERCO application did not expect a sufficient curing effect in the BS area.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.45 no.1
• /
• pp.44-49
• /
• 2000

This study was conducted to assess the allelopathic potentiality of Korea traditional seventy-nine rice (Oryza sativa L.) cultivars on barnyardgrass (Echinochloa crus-galli P. Beauv. var. oryzicola Ohwi) and to identify possible allelopathic compounds from selected rice cultivars, such as Seogandodobyeo, Huadobyeo and Heugbalbyeo. In the straw mixture, Seogandodobyeo showed the greatest inhibition (67.07%) on total emergence percentage. The greatest inhibition on total seedling length and dry weight of barnyardgrass occurred in Huadobyeo (58.32 %) and Heugbalbyeo (81.20%), respectively. An HPLC analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compound depend upon the cultivars. Four compounds including Ο-coumaric acid in Seogandodobyeo extracts, four compounds including p-coumaric acid in Huadobyeo extracts, and seven compounds including Ο-coumaric acid in Heugbalbyeo were detected, respectively. Ο-coumaric acid (0.97 mg/g) in Seogandodobyeo, p-coumaric acid (0.92mg/g) in Huadobyeo and Ο-coumaric acid (1.02 mg/g) in Heugbalbyeo was detected as the highest amounts, respectively. The preliminary identification by HPLC analysis resulted in peaks with retention times close to those of standards which were confirmed with EI/MS. The mass spectra of p-coumaric, and Ο-coumaric acids showed molecular ions (m/z) at 164 and 164, and their base peaks (m/z) at 164 and 118, respectively.

• Fisheries and Aquatic Sciences
• /
• v.18 no.2
• /
• pp.165-171
• /
• 2015

Abalone containing phlorotannins is produced by feeding the phlorotannin-rich brown seaweed Eisenia bicyclis after 4 days of starvation. Reverse-phase high-performance liquid chromatography (RP-HPLC) was used to isolate and quantify phlorotannins, which were identified by mass spectrometry and [$^1H$]-nuclear magnetic resonance to be the P1 compound, 7-phloroeckol, and eckol. When E. bicyclis was used as feed, P1 compound accumulated to an average of 1.60 mg/g dry weight of abalone muscle tissue after 18 d, 7-phloroeckolol to 0.21 mg/g after 16 d, and eckol to 0.22 mg/g after 12 d. Saccharina japonica was used as a control feed, and the abalone showed little or no accumulation of phlorotannins in muscle tissue. Feed consumption and growth rate were very similar when either E. bicyclis or S. japonica was fed for 20 d. Half-maximal reductions in the levels of P1 compound, 7-phloroeckol, and eckol accumulation were attained in 1.5, 1.9, and 3.4 days, respectively, after the feed was switched from E. bicyclis to S. japonica. Value-added abalone containing bioactive phlorotannins can be produced by simply changing the feed to the phlorotannin-rich E. bicyclis 18 d prior to harvesting.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.20 no.12
• /
• pp.1161-1167
• /
• 2010

This paper presents experimental performance evaluation of a magnetorheological(MR) damper for integrated isolation mount for ultra-precision manufacturing system. The vibration sources of the ultra-precision manufacturing system can be classified as follows: the one is the environmental vibration from the floor and the other is the transient vibration occurred from stage moving. The transient vibration occurred from the stage moving has serious adverse effect to the process because the vibration scale is quite larger than other vibrations. Therefore in this research, a semi-active MR damper, which can control the transient vibration, is adopted. Also the stage needs to be isolated from tiny vibrations from the floor. For this purpose, a dry-frictionless MR damper is required. In order to achieve this goal, a novel type of MR damper is originally designed and manufactured in this work. Subsequently, the damping force characteristics of MR damper are evaluated by simulation and experiment. In addition, the vibration control performance of the MR damper associated with the stage mass is evaluated.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.17 no.3
• /
• pp.155-161
• /
• 2014

Purpose: Constipation is a common pediatric problem worldwide. This study aims to describe the clinical characteristics of pediatric constipation in south Jordan according to gender and age group. Methods: All patients with constipation managed at our pediatric gastroenterology service between September 2009 and December 2012 were included. Hospital charts were reviewed. Demographic data, clinical characteristics, and final diagnosis were recorded. Data were analyzed according to gender and the following age groups: infants, pre-school, school age, and adolescents. Results: During the study period, 126 patients were enrolled. The number (percentage) of patients according to age were the following infants: 43 (34.1%), pre-school: 55 (43.7%), school age: 25 (19.8%), and adolescents: 3 (2.4%). Males made up 54.8% of the study population. There were no statistical gender differences in any age group. The most common symptom in all age groups was dry, hard stool. Infrequent defecation was found in almost one-half of the patients. Fecal incontinence was more common in school-aged children compared to pre-school-aged children and adolescents. Abdominal pain was seen in almost 40% of the constipated children. Abdominal pain was more prevalent in girls and older children. Fecal mass in the rectum was the most common physical finding, with constipated boys exhibiting higher rates. Functional constipation was the most common etiology. Conclusion: Clinical characteristics of constipation in children vary according to age group and gender. Older children had less frequent bowel motions, a longer duration of symptoms, and a higher prevalence of long-standing constipation compilations (fecal incontinence and abdominal pain).

• Korean Journal of Ecology and Environment
• /
• v.48 no.4
• /
• pp.280-286
• /
• 2015

Life cycles of Sweltsa illiesi and S. lepnevae were determined from a headwater stream in Mt. Jumbong. Identification of nymphs was done by using DNA barcoding. Nymphs begin to have species specific color pattern on their head several months prior to adult emergence and differ in the form of the third antennal segment. Two species appear to have similar semivoltine life cycles in this stream, beginning to hatch from June and finishing adult emergence about 701 days later. The combined annual mean biomass in ash free dry mass (AFDM) was estimated as $96mg\;AFDM\;m^{-2}$. The combined annual secondary production were 373 mg and $297mg\;AFDM\;m^{-2}\;yr^{-1}$, calculated by using size frequency method and increment summation method respectively.

• The Korean Journal of Mycology
• /
• v.40 no.4
• /
• pp.292-295
• /
• 2012

Trametes versicolor, a common inhabitant of dead hardwoods in temperate climates, belongs to one of the important medicinal mushrooms. In this study, spent coffee ground(SCG), instant coffee powder(ICP) and instant decaffeinated coffee powder(IDCP) were examined for their effect on the mycelial growth of T. versicolor. Adding SCG was proven to be significantly beneficial at the concentration as high as 10%. ICP and IDCP, both containing concentrated polyphenols, were also beneficial at low concentration less than 1%. 1% SCG culture resulted in ten-fold increased yield of dry cell mass compared to the control culture. Adding coffee substances was recommended as a useful tool for accelerating the growth and strengthening the physiological activity of the mycelium.

• Proceedings of the Korean Society of Laser Processing Conference
• /
• 2005.11a
• /
• pp.37-41
• /
• 2005

When screen size of the Flat Panel Display (FPD) becomes larger, the traditional photo-lithography using photomasks and UV lamps might not be possible to make patterns on Photo Resist (PR) material due to limitation of the mask size. Though the maskless photo-lithography using UV lasers and scanners had been developed to implement large screen display, it was very slow to apply the process for mass-production systems. The laser exposure system using 405 nm semi-conductor lasers and Digital Micromirror Devices (DMD) has been developed to overcome above-mentioned problems and make more than 100 inches FPD devices. It makes very fine patterns for full HD display and exposes them very fast. The optical engines which contain DMD, Micro Lens Array (MLA) and projection lenses are designed for 10 to 50 ${\mu}m$ bitmap pattern resolutions. The test patterns for LCD and PDP displays are exposed on PR and Dry Film Resists (DFR) which are coated or laminated on some specific substrates and developed. The fabricated edges of the sample patterns are well-defined and the results are satisfied with tight manufacturing requirements.

• International Journal of Air-Conditioning and Refrigeration
• /
• v.13 no.2
• /
• pp.107-118
• /
• 2005

An experimental investigation was made to study two-phase flow distribution in a T-type distributor of slit fin-and-tube heat exchanger using R-22. Experiments were carried out under the conditions of saturation temperature of $5^{\circ}C$ and mass flow rate varying from 0.6 to 1.2kg/min. The inlet air has dry bulb temperature of $27^{\circ}C$, relative humidity of 50% and air velocity varying from 0.63 to 1.71m/s. A comparison was made between the predictions from the previously proposed tube-by-tube method and the present experimental data for the heat transfer rate of evaporator. Results show that $82.5\%$ increase of air velocity is needed for T-type distributor with four outlet branches than that of two outlet branches under the superheat of $5^{\circ}C$, which resulted in increasing of air-side pressure drop of $130\%$ for the former as compared to the latter.

• Journal of Welding and Joining
• /
• v.26 no.4
• /
• pp.44-49
• /
• 2008

Generally, wear plate is steel plate having improved surface contact strength and impact strength by surface hardening which is welded using materials with good corrosion resistance, wear resistance and thermal resistance property. CFP GMAW(Compound Filler Plate Gas Metal Arc Welding) is the cladding method using GMAW with the CFP, which is bound with waterglass, on the substrate. It has advantages of reducing compound powder loss, uniform penetration, and preventing hardness decrease. To develope mass production technique of CFP GMAW process for production of high quality wear plate, the method for controling shallow penetration and increasing productivity is required. In this study, twin torch method applied to CFP GMAW process for increasing productivity. And the method was developed by controling penetration control, CFP dry time, gas formation flux and water glass concentration. As a result, applying twin torch method to CFP GMAW process was possible and high quality wide bead could be made without overlap joint.