• Atmosphere
• /
• v.33 no.2
• /
• pp.105-124
• /
• 2023

Research papers published in the Korean Meteorological Society (KMS) journals by the members of KMS since the establishment of KMS in 1963 in the field of atmospheric physics are summarized. A significant number of research papers published in other international journals are also cited in this paper to highlight the achievement of the KMS members in international academic community. The aim is to illustrate the historical development of research activities of the KMS members in the field of atmospheric physics, and indeed it is found that the KMS members have made enormous progress in research publications quantitatively and qualitatively in the field of atmospheric physics. In detail, however, observational studies of aerosol physical properties and cloud and precipitation physics were very active, and studies on cloud physics parameterization for cloud modeling were highly recognized in the world, but observational and theoretical studies of atmospheric radiation were relatively lacking and solicit more contribution from the KMS members.

• Journal of the Korean Society of Radiology
• /
• v.17 no.2
• /
• pp.191-199
• /
• 2023

This study aimed to propose minimized radiation doses with an optimized abdomen x-ray image, which realizes a Deep Blind Image Super-Resolution Generative adversarial network (BSRGAN) technique. Entrance surface doses (ESD) measured were collected by changing exposure conditions. In the identical exposures, abdominal images were acquired and were processed with the BSRGAN. The images reconstructed by the BSRGAN were compared to a reference image with 80 kVp and 320 mA, which was evaluated by mean squared error (MSE), peak signal-to-noise ratio (PSNR), and structural similarity index measure (SSIM). In addition, signal profile analysis was employed to validate the effect of the images reconstructed by the BSRGAN. The exposure conditions with the lowest MSE (about 0.285) were shown in 90 kVp, 125 mA and 100 kVp, 100 mA, which decreased the ESD in about 52 to 53% reduction), exhibiting PSNR = 37.694 and SSIM = 0.999. The signal intensity variations in the optimized conditions rather decreased than that of the reference image. This means that the optimized exposure conditions would obtain reasonable image quality with a substantial decrease of the radiation dose, indicating it could sufficiently reflect the concept of As Low As Reasonably Achievable (ALARA) as the principle of radiation protection.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.27 no.2
• /
• pp.77-84
• /
• 2023

As the installation of solar panel accelerates, so does the number of solar panels reaching their end-of-life (EOL). However, the EOL solar panels is becoming a concern, as they contain potentially hazardous materials and are not easily recycled. Coping strategies such as effective collection, disposal, and recycling methods will be important to manage the growing number of EOL solar panels in the coming years.Therefore, many studies have focused on the development of EOL solar panel recycling technology. One recycling technology for EOL solar panels applicable to the construction field is the application of extracted tempered glass from EOL solar panels as construction materials. This study summarized the EOL solar panel disassembly technology and evaluated the mechanical properties of mortar using extracted tempered glass as fine aggregate. The results showed that when tempered glass was used as a fine aggregate in mortar, the compressive strength, flexural strength, and macro pores in the 1-3 ㎛ with 200-300 ㎛ range were affected, regardless of the disassembly technology of EOL solar panels. Especially, we found that the mechanical performance of mortar using chemically treated tempered glass was noticeably decreased due to changes in the chemical composition of the extracted tempered glass resulting from the removal of K₂O and CuO due to chemical reactions. Meanwhile, it was found that when fly ash was used as a binder, the reduction of mechanical performance could be alleviated.

• Journal of Aerospace System Engineering
• /
• v.18 no.3
• /
• pp.70-75
• /
• 2024

The insulation performance of a common bulkhead propellant tank for small launch vehicles with variations in insulation thickness was analyzed. The common bulkhead propellant tank composed of a single part allows for lightweight design, as it eliminates the need for tank connections. However, problems such as propellant loss and ignition delay due to heat transfer caused by temperature differences between oxidizer and fuel may arise. Therefore, it is essential to verify the insulation performance of the common bulkhead structure that separates the oxidizer tank and fuel tank. In this study, transient heat transfer analysis was conducted for propellant tanks with insulation thicknesses of (50, 55, 60, 65, and 70) mm to analyze the insulation performance using boil-off mass. Subsequently, the boil-off mass of the oxidizer generated during the first-stage flight time of the propellant tank was determined. The results confirmed that increasing the insulation thickness reduces the boil-off mass, thereby improving the insulation performance.

• Journal of Dairy Science and Biotechnology
• /
• v.42 no.2
• /
• pp.64-76
• /
• 2024

This study analyzed the physicochemical properties and rheology of frozen condensed skim milk during thawing at 5 room temperature (20℃). The viscosity of the condensed milk was 80 cps (21.5℃) immediately after manufacture, and this value was decreased to 0 cps (21. 5℃) during storage at day 7. The particle sizes of the condensed skim milk were 0.128 mm just after manufacture, and 0.522 and 0.818 mm at days 3 and 5 of thawing at 20℃, respectively. Condensed skim milk with no temperature abuse had lower acidity than those stored at room temperature on the 3rd and 7th days. Additionally, a sandy texture was observed as the thawing period increased. Based on the comprehensive results of this study, when frozen condensed skim milk is added to a product as a raw material, the longer the thawing period at room temperature, the longer the ice crystals inside melt and become water drips. Quality defects, such as weight loss, decreased pH, protein denaturation, and texture deterioration, are expected to occur.

• Pediatric Infection and Vaccine
• /
• v.14 no.1
• /
• pp.69-74
• /
• 2007

Purpose : Human coronanviruses (hCovs) including hCoV-229E and hCoV-OC43 have been known as etiologic agents of the common colds and were regarded as clinically insignificant agents. However, recent identification of hCoV-NL63 and hCoV-HKU1 in children with lower respiratory tract infections has evoked the clinical concerns about their prevalence and the clinical significance of these hCoVs in children. This study was performed to investigate the prevalence of hCoVs in children with community-acquired pneumonia. Methods : From March 2006 to January 2007, nasopharyngeal specimens collected from children hospitalized with pneumonia, were tested for the presence of common respiratory viruses (respiratory syncytial virus, influenza A, influenza B, parainfluenza viruses, and adenovirus) using multiplex reverse transcriptase polymerase chain reaction (RT-PCR). Human metapneumovirus (hMPV) infection was excluded by nested RT-PCR using primers for the F-gene. To detect the different strains of hCoVs, nested RT-PCR assays specific for hCoVNL63, hCoV-OC43, hCoV-229E, and hCoV-HKU1 were performed. Results : Out of the 217 nasopharyngeal aspirate from children aged under 15 years, respiratory syncytial virus (RSV) was detected in 32 patients, hMPV in 18, human parainfluenza virus in 10, influenza virus A in 2, and adenovirus in 6. HCoVs were detected by RT-PCR in 8 (3.7%) of the 217 patients, hCoV-229E in 1, hCoV-NL63 in 3, and hCoVOC43 in 4 patients. HCoV-HKU1 was not detected in this study population. Conclusion : Recently identified hCoV-NL63 and hCoV-HKU1 seemed to have a little clinical significance in Korean children with severe or hospitalized community-acquired pneumonia.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.19 no.4
• /
• pp.334-344
• /
• 2013

In order to understand the characteristics of oceanic environment in the coastal aquaculture waters of the East Sea, the observation of the CTD (temperature and salinity), dissolved oxygen, chlorophyll a and N/P (DIN ($NO_2$-N, $NO_3$-N, $NH_4$-N) : DIP($PO_4$-P)) ratio was carried out at Sokcho, Jukbyon and Gampo in February, April, June, August, October, December 2013. Based on T(temperature)-S(salinity) diagram analysis, the water masses in the study area were divided into 3 groups; Tsushima Surface Water (TSW: $20-28.3^{\circ}C$ temperatures and 31.04-33.75 salinities), Tsushima Middle Water (TMW: $8.1-16.3^{\circ}C$ and 33.00-34.49), and North Korean Cold Water (NKCW: $1.8-9.4^{\circ}C$ and 33.78-34.42). In winter, DO concentrations in the northern part were higher than those in southern part. In spring and fall, they were low in the surface layer, and increased in summer. Chl-a concentrations < $0.4{\mu}g/L$ dominated in February, April, October and December. Chl-a concentrations were higher in June and August. In particular, the highest Chl-a concentration > $2{\mu}g/L$ was observed in the middle layer of Gampo in August. In February, April, June and December, the N/P ratio in the most of the water masses was less than the Redfield ratio (16), indicating that nitrate did act as a limiting factor in phytoplankton growth. On the contrary, in August and October, the N/P ratio in surface and sub-surface layer was greater than the Redfield ratio, suggesting that phosphate was a limiting factor.

• Atmosphere
• /
• v.25 no.1
• /
• pp.185-191
• /
• 2015

Ambient measurements of aerosol light absorption (${\sigma}_a$) and scattering coefficients (${\sigma}_s$) were done at Gosan climate observatory during summer 2008 using a 3-wavelength photoacoustic soot spectrometer (PASS). PASS was deployed photoacoustic method for light absorption and integrated nephelometry for light scattering measurements. The ${\sigma}_a$ and ${\sigma}_s$ from PASS were compared with those from co-located aethalometer and nephelometer measurements. The aethalometer measurements of ${\sigma}_a$ correlated reasonably well with photoacoustic measurements, but the slope of the linear fitting line indicated the PASS measurement values of ${\sigma}_a$ were larger by a factor of 1.53. The nephelometer measurement values of ${\sigma}_s$ correlated very well with PASS measurements of ${\sigma}_s$, with a slope of 1.12 and a small offset. Comparing to the aethalometer measurements, the photoacoustic measurements of ${\sigma}_a$ didn't exhibit a significant (i.e., the ratio between aethalometer and PASS increased) change with increasing relative humidity (RH). The ratio of ${\sigma}_s$ between nephelometer and PASS increased with increasing RH, especially when the RH increased beyond 80%. This apparent increase in ${\sigma}_s$ with RH may be due to the contribution of hygroscopic growth of aerosols.

• Journal of the Korean Wood Science and Technology
• /
• v.36 no.6
• /
• pp.77-87
• /
• 2008

Wooden model erosion control dam was made with pitch pine, of which the strength properties was evaluated. Wooden model erosion control dam was made with diameter 90 mm of pitch pine round posts treated with CUAZ-2 (Copper Azole), changing joint in three different types. In each type, erosion control dam was made in nine floor (cross-bar of five floors and vertical-bar of four floors), of which the hight was 790 mm. And then strength properties were investigated through horizontal loading test and impact strength test, and the deformation of structure through image processing (AICON 3D DPA-PRO system). In horizontal loading test of wooden model erosion control dam using round post of diameter 90 mm, whether there was stone or not did not affect strength much when using self drill screw, but strength was decreased by 23%. In monolithic type of erosion control dam using screw bar, strength was increased by 1.5 times and deformation was decreased when filling with stone. When reinforcing with screw bar that ring is connected to self drill screw, strength was increased by 4.8 times. In impact strength test of wooden model erosion control dam made with round post of diameter 90 mm, the erosion control dam connected with self drilling screw not filling with stone was totally destroyed by the 1st impact, and the erosion control dam using screw bar was ruptured at cross-bar at which 779 kgf of impact was loaded in the 1st impact. In the 2nd impact, the base parts were ruptured, and reaction force was decreased to 545 kgf. In the 3rd impact, whole base parts were destroyed, and reaction force was decreased to 263 kgf.

• Journal of Animal Science and Technology
• /
• v.52 no.1
• /
• pp.37-42
• /
• 2010

A study was conducted to examine the effect of the castration time on growth, meat quality and fatty acid composition of Korean black goats. Forty five male kids were divided into five groups, including control (without castration) and four groups with the kids castrated at 0.5, 3, 5 and 7 months of age, respectively. Average daily body weight gain (ADG) for control was significantly (P<0.05) higher than the castrated groups. ADG did not differ between the castrated groups. The ADG of the male kids castrated at 3 and 5 months of age tended to be higher than the other castrated groups. Dressing percentage for 0.5 months-castrated group was higher than 7 months-castrated group. Retail cut percentages for control was higher (P<0.05) than others, but the retail cut percentages did not differ between the castrated groups. Compared with control, higher fat percentages of carcasses appeared in the castrated groups (P<0.05). The fat percentages gradually increased in earlier castrated animals. As castrated earlier, moisture contents tended to decrease, whereas crude protein and fat contents tended to increase. The different castration time did not affect physical properties of goat meat (shear force, cooking loss, and water holding capacity). Results from panel tests showed that juiciness or tenderness of meats for 5 months-castrated group tended to be higher than those for the other groups. The flavor of meatfor 7-months castrated group appeared to be more favorable compared with 0.5- or 3-months castrated groups (P<0.05). The proportion of saturated fatty acid in meat washigher for 5-months castrated group and lower for 3-months castrated group as compared to the other castrated groups, whereas the proportion of unsaturated fatty acid was vice versa (P<0.05). Mono-unsaturated fatty acid contents did not differ between thecastrated groups. Present results indicatedthat castration at 3 or 5 months of age increased growth performance and meat quality of Korean black goats.