• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.3
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• pp.237-251
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• 2013

This study aimed to estimate the axial stress and torque on a shaft in a disc cutter. The corresponding inner temperature and the surface temperature of a cutter ring were also measured by using strain gauges and thermocouples during the linear cutting tests. The maximum values of the axial stress and torque were recorded to 11.3 MPa, $171kN{\cdot}m$ respectively. They have higher correlations with normal force rather than rolling force. The results of temperature measured by thermocouples during a linear cutting test showed that the rate of increase in temperature was below $0.2^{\circ}C$. When the cutter spacing is set to be 70 mm, the inner temperature and surface temperature of a disc cutter were $0.1^{\circ}C/m$, $0.15{\sim}0.17^{\circ}C/m$ respectively. Similarly, when the cutter spacing is 90 mm, the temperature values were $0.09^{\circ}C/m$, $0.13{\sim}0.23^{\circ}C/m$ respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11C
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• pp.1044-1051
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• 2006

System level diagnosis algorithms use the properties of t-diagnosable system where the maximum number of the faults does not exceed 1. The existing diagnosis algorithms have limit when dealing with large fault sets in large multiprocessor systems. Somani and Peleg proposed t/k-diagnosable system to diagnose more faults than t by allowing upper bounded few number of units to be diagnosed incorrectly. In this paper, we propose adaptive hypercube diagnosis algorithm using t/k-diagnosable system. When the number of faults exceeds t, we allow k faults to be diagnosed incorrectly. Simulation shows that the performance of the proposed algorithm is better than Feng's HADA algorithm. We propose new algorithm to reduce test rounds by analyzing the syndrome of RGC-ring obtained in the first step of HADA/IHADA method. The proposed algorithm also gives similar performance compared to HYP-DIAG algorithm.

• Advances in concrete construction
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• v.14 no.2
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• pp.93-102
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• 2022

In this study, limestone powder (LS) and fly ash (FA) were used as powder materials in self-compacting concrete (SCC) in increasing quantities in addition to cement, so that the two powders commonly used in the production of SCC could be compared in the same study. Considering the reduction of the maximum aggregate size in SCC, 10 mm or 16 mm was selected as the coarse aggregate size. The properties of fresh concrete were determined by slump flow (including T₅₀₀ time), V-funnel and J-ring experiments. The experimental results showed that as the amount of both LS and FA increased, the slump flow also increased. The increase in powder material had a negative effect on V-funnel flow times, causing it to increase; however, the increase in FA concretes was smaller compared to LS ones. The increase in the powder content reduced the amount of blockage in the J-ring test for both aggregate sizes. As the hardened concrete properties, the compressive and splitting strengths as well as the modulus of elasticity were determined. Longitudinal and transverse deformations were measured by attaching a special frame to the cylindrical specimens and the values of Poisson's ratio, initiation and critical stresses were obtained. Despite having a similar W/C ratio, all SCC exhibited higher compressive strength than NVC. Compressive strength increased with increasing powder content for both LS and FA; however, the increase of the FA was higher than the LS due to the pozzolanic effect. SCC with a coarse aggregate size of 16 mm showed higher strength than 10 mm for both powders. Similarly, the modulus of elasticity increased with the amount of powder material. Inelastic properties, which are rarely found in the literature for SCC, were determined by measuring the initial and critical stresses. Crack formation in SCC begins under lower stresses (corresponding to lower initial stresses) than in normal concretes, while critical stresses indicate a more brittle behavior by taking higher values.

• Journal of the Korean Society for Nondestructive Testing
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• v.14 no.2
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• pp.112-121
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• 1994

This paper discusses the feasibility of ultrasonic C-scan technique for nondestructive evaluation of spot weld quality. Ultrasonic evaluation for spot weld quality was performed by immersion method with the mechanical and the electronic scanning of point-focussed ultrasonic beam(25 MHz). For the sake of the approach to the quantitative measurement of nugget diameter and the discrimination of the corona bond from nugget, preliminary infinitesimal gap experiment by newton ring is tried in order to set up the optimum ultrasonic test condition. Ultrasonic image data obtained were confirmed and compared by optical microscope and SAM(Scanning Acoustic Microscope) observation of the spot-weld cross section. The results show that the nugget diameter can be measured with the accuracy of 1.0mm, and voids included in nugget can be detected to $10{\mu}m$ extent with simplicity and accuracy. Finally, it was found that it is necessary to make a profound study of definite discrimination of corona bond from nugget and the approach of quantitative evaluation of nugget diameter by utilizing the various image processing techniques.

• The Korean Journal of Food And Nutrition
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• v.6 no.4
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• pp.255-267
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• 1993

This study was performed to investigate the correlations among physical anthropometric measurement, diet intakes, physical fitness test, and serum lipids in eight sedentary women(control group), and twenty seven exercising women(aerobic groups), aged 35~45 years. The results of the study are as follows : 1) systolic blood pressure(SBP) and diastolic blood pressure(DBP) of aerobic groups were lower than serf entary. Pulse rate was decreased according to the length of aerobic periods. Muscular endurance and jump power of all subjects were stronger than standard range, and those of aerobic exercising groups were stronger than control group. Muscular power of the upper half of the body In all subjects were lower than standard range. 2) Daily calorie intakes of all subjects were in the ring: of recommended dietary allowances (RDA) for Koreans. But daily protein Intakes were higher than RDA. daily cholestrol intakes of all subjects were slightly less than 200~300 mg: which is normal consumption of Koreans. 3) There was a significant positive correlation between serum 7G and daily protein intakes. It was considered that excessive protein intake converted to serum 7G. There was not a significant correlation between serum TC and dietary TC. Therefore, dietary TC seemed to have not much effect on serum TC. Physical fitness was negatively related to serum TG, TC, LDL-C, but positively related to HDL-C, HDL-C /TC. It was found that the serum lipids could be changed better according to improving the physical fitness. There were significant positive correlations between SBP and serum TC, LDL-C. (According to this results), the higher SBP, the higher serum TC, LDL-C tended to be. There was a significant positive correlations between sit up and weightloss nth exercise r=0.7(p<0.001), push ups and weightless with exercise r=0.5(p<0.001). It was considered that muscle strength could be improved according to the weightloss. 4) The purpose of exercise in aerobic groups was rather promoting health than reducing body fatness. Most of al1 subjects (83.2%) drank caffeine-contained beverage therefore, we should concern about that absorption of Fe could be Interrupted and blood pressure could be elevated by caffeine.

• Journal of fish pathology
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• v.36 no.2
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• pp.263-275
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• 2023

Chum salmon (Oncorhynchus keta) is a species which returns to Korea for spawning and was produced as seed production at the Fisheries Resources Agency located in Uljin-gun, Gyeongsangbuk-do to preserve the species. However, farmed chum salmon showed symptoms of bacterial infection. Therefore, in this study, bacteria were isolated to identify the causative agent from chum salmon in October 2021. The isolated bacteria were identified based on the sequences of 16S rDNA, rpoD (RNA polymerase sigma factor σ⁷⁰), and vapA (A-layer) genes. Also, salinity-growth curve, biochemical characterization, antibiotic susceptibility test, and pathogenicity analysis were performed in four strains. As a result, four isolated strains were identified as Aeromonas salmonicida subsp. salmonicida. Additionally, the bacterial strains showed a decrease in growth as the salt concentration increased in the medium. All of the isolated strains exhibited γ-hemolysis, and the same biochemical properties. In the antimicrobial susceptibility test, all strains showed an inhibition zone of 40 to 44 mm for oxolinic acid, flumequine, and florfenicol. Pathogenic factors were assessed by RT-PCR at the mRNA level, and found that the four strains expresses the outer membrane ring of T3SS (ascV), inner membrane ring of T3SS (ascC), vapA, enterotoxin (act), and lipase (lip) genes which are well known to significantly contribute to the pathogenicity of A. salmonicida. The results of this study can be used as basic data to prevent A. salmonicida subsp. salmonicida occurring in sea-chum salmon in the future.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.4
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• pp.130-137
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• 2003

In this study, Isolation was attempted to acquire a phenol utilizing bacterium for PAH degradation and to investigate the characteristics of PAH degradation. The isolate was identified by BIOLOG test as Stenotrophomonas maltophilia. Lower first order reaction constant was detected in the presence of lower phenol concentration. The yield coefficient of phenol was 0.1447mg cell/mg phenol. In the presence of naphthalene and phenol, phenol degradation was favorable. The isolate was capable of utilize naphthalene and phenanthrene as growth substrate but PAH, containing over 4-ring structure such as pyrene, was not degradable. The possible phenanthrene degradation pathway would be the addition of two hydroxy group on C-1 and C-2 position, followed by ortho cleavage, and then decarboxylation.

• Nuclear Engineering and Technology
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• v.50 no.2
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• pp.218-222
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• 2018

An oxide-dispersion-strengthened (ODS) layer was formed on Zircaloy-4 tubes by a laser beam scanning process to increase mechanical strength. Laser beam was used to scan the yttrium oxide ($Y_2O_3$)-coated Zircaloy-4 tube to induce the penetration of $Y_2O_3$ particles into Zircaloy-4. Laser surface treatment resulted in the formation of an ODS layer as well as microstructural phase transformation at the surface of the tube. The mechanical strength of Zircaloy-4 increased with the formation of the ODS layer. The ring-tensile strength of Zircaloy-4 increased from 790 to 870 MPa at room temperature, from 500 to 575 MPa at $380^{\circ}C$, and from 385 to 470 MPa at $500^{\circ}C$. Strengthening became more effective as the test temperature increased. It was noted that brittle fracture occurred at room temperature, which was not observed at elevated temperatures. Resistance to dynamic high-temperature bursting improved. The burst temperature increased from 760 to $830^{\circ}C$ at a heating rate of $5^{\circ}C/s$ and internal pressure of 8.3 MPa. The burst opening was also smaller than those in fresh Zircaloy-4 tubes. This method is expected to enhance the safety of Zr fuel cladding tubes owing to the improvement of their mechanical properties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.7 no.1
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• pp.31-63
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• 1969

A series of experiment was carried out to study on the production of disease-free seed potatoes at the Alpine Experiment Station from 1960 to 1968, which initiated a study of comparison on degeneration of plain warm region and high altitude products and the effect of latent potato virus X (PVX) and potato leaf roll virus(PLRV) on degeneration. Particular observations were made on some aspect of the nature of potato virus disease and its control such as concentrations of PVX, range of host plants, physical properties such as concentrations of PYX, range of host plants, physical properties and carrying effect of insects, by investigating 9 different areas of the main potato producing regions (Kimhae, Taegu, Choongju, Taejoen, Suwon, Kwangju, Chonju, Cheju and Chinju). Highly purified anti-serum was separated and tested for control of the virus disease and also various method of prevention and control of PLRV were observed, using cultivation of sprouted seed tubers, early harvesting method, and systemic chemicals. The results obtained are summarized as follows; 1. Potato yield in the plain region decreased by 32.8~66.3% in the first year cultivation of seed potatoes from colder region, and the rate of virus infection was 92.9 to 95.4%. 2. Plants of three families including, 20 species were susceptible to the PVX, and among the plants Salvia officinalis of a habits only was the carrier while the symptom of Digitalis purpurea of Screphulariaceae was masked. Necrosis and ring spot was occurred in most pJants of the Solanaceae and ring spot symptom also was observed in Nicotiana tabacum L. var. White Burley and in N. glutinosa. 3. The 8$C_2$ strain of virus had the following physical properties; thermal inactivation point, 68-$72^{\circ}C$ : dilution inactivation point, above 1, 000, 000 dilution: ageing in vitro, 240-360 days: and ageing in dry plant tissue, 30 days. 4. Myzus persicae and Oxya spp. did not transmit the 8$C_2$ strain of potato virus. 5. Virus was purified through the ammonium sulphate isolating method, and higher titer value, 1/2048 was obtained through anti-serum test. 6. Inhibition Chenopodiacae on the virus infection of potato was remarkable, and inhibition of local lesion host also was observed. 7, By earlier planting of sprouted seed tubers, growth period could be prolonged by 10 to 12 days. 8. Earlier harvest decreased much the rate of virus infection of seed potatoes. 9. According to the results of aphid control trial using systemic soil insecticides at Kangnung and Taekwanlyung, PSP 204, Disyston and Thimet was effective to aphid control. In particular, control effect of twice treatments of PSP 204 was great. 10. Treatmental effect of those chemicals lasted about 60-70 days. However, single foliar application of emulsified chemicals was not effective to potato virus control. 11. The effect of PSP 204, Disyston, and Thimet on the control of potato leaf roll virus was great, particularly in the case of two treatments of PSP 204, at Kangnung as well as at Taekwanlyung. Higher negative correlationship between the control effect of potato leaf roll virus and potato yield was observed showing the value r=-0.85 at Kangnung, and r=-0.87 at Taekwanlyung. 12. Differences in the control effects among PSP 204, Disyston, and Thimet was not noticed.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.263-263
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• 2006

Poly (ethylene glycol)(PEG) - Poly (${\varepsilon}-caprolactone(CL)$) - Poly (D,L lactide(LA) (PCLA-PEG-PCLA) was synthesized by ring-opening polymerization to form temperature sensitive hydrogel triblock copolymer. The triblock copolymer was acrylated by acryloyl chloride. ${\beta}-amino$ ester was used as a pH sensitive moiety, in this study ${\beta}$- amino ester obtained from 1,4-butandiol diacrylate, and 4, 4' trimethylene dipiperidine, it have pKb around 6.6. pH/temperature sensitive penta-block copolymer (PAE-PCL-PEG-PCL-PAE) was synthesized by addition polymerization from acrylated triblock copolymer, 1,4-butandiol diacrylate, and 4, 4' trimethylene dipiperidine. Their physicochemical properties of triblock and penta-block copolymers were characterized by $^1H-NMR$ spectroscopy and gel permeation spectroscopy. Sol-gel phase transition behavior of PAE-PCL-PEG-PCL-PAE block copolymers were investigated by remains stable method. Aqueous media of the penta-block copolymer (at 20 wt%) changed from a sol phase at pH 6.4 and $10^{\circ}C$ to a gel phase at pH 7.4 and $37^{\circ}C$. The sol-gel transition properties of these block copolymers are influenced by the hydrophobic/hydrophilic balance of the copolymers, block length, hydrophobicity, stereo-regularity of the hydrophobic of the block copolymer, and the ionization of the pH function groups in the copolymer depended on the changing of environmental pH, respectively. The degradation and the stabilization at pH 7.4 and $37^{\circ}C$, and the stabilization at pH 6.4 and $10^{\circ}C,\;5^{\circ}C,\;0^{\circ}C$, of the gel were determined. The results of toxicity experiment show that the penta block copolymer can be used for injection drug delivery system. The sol?gel transition of this block copolymer also study by in vitro test ($200{\mu}l$ aqueous solution at 20wt% polymer was injected to mouse). Insulin loading and releasing by in vitro test was investigated, the results showed that insulin can loading easily into polymer matrix and release time is around 14-16days. The PAE-PCL-PEG-PCL-PAE can be used as biomaterial for drug, protein, gene loading and delivery.