• Journal of the Korean Magnetics Society
• /
• v.7 no.4
• /
• pp.173-179
• /
• 1997

Change in phases, microstructures, and magnetic properties by the variation of quench rate and heat treatment were investigated for melt-spun $Fe_{77}Pr_{15}C_8$ ribbons. The amorphization of as-spun ribbons increased as the quench rate increased. As a result, the ribbon quenched at 40 m/s was almost entirely amorphous. Similarly to cast alloys, the primary phase in crystalline ribbons quenched at 10 m/s was $\alpha$-Fe followed by the secondary $Fe_{17}Pr_2C_x$. Crystalline phases were still dominant in the ribbon spun at 20 m/s, but in this case crystallization of $Fe_{17}Pr_2C_x$ was remarkable with a little suppression of $\alpha$-Fe. At 30 m/s an amorphous phase obviously dominated in the as-spun ribbons with small fraction of crystals. Therefore, substantial amount of hard magnetic $Fe_{14}Pr_2C$ was not obtained from the as-spun state but, as in cast alloys, produced only by a solid-state transformation. Within a few minutes fine grains of $Fe_{14}Pr_2C$ were easily obtained at relatively low temperature when the degree of amorphization of as-spun ribbons was higher. The grain size of $Fe_{14}Pr_2C$ was well less than 1${\mu}{\textrm}{m}$. The ribbons quenched at 20 or 30 m/s yielded higher coercivities after heat treatment.

• Journal of Life Science
• /
• v.26 no.10
• /
• pp.1163-1168
• /
• 2016

Plant growth-promoting rhizobacteria (PGPR) have gained worldwide importance and acceptance due to their agricultural benefits. These microorganisms are potential tools for sustainable agriculture, with effects on plant growth, biofertilization, induced systemic resistance, and biocontrol of plant pathogens. In this study, four different Pantoea species were isolated from field soil, and their plant growth-promoting characteristics were studied. Based on 16S rDNA gene sequencing analyses, the se were grouped into Pantoea ananatis, Pantoea citrea, Pantoea dispersa, Pantoea vagans and named as Pa1, Pc1, Pd1, Pv1, respectively. All of these strains have their ability for solubilization of insoluble phosphate depending on pH decrease at the range around pH 5 at 1days after inoculation and production of plant hormone indole acetic acid (IAA) with 85.3±16.3 μg/ml of Pa1, 183.9±16.8 μg/ml of Pc1, 28.8±17.3 μg/ml of Pd1 and 114.1±16.5 μg/ml of Pv1, respectively. Pa1, Pc1 and Pd1 also have high activity for production of gibberellin (GA₃) hormone with 331.1±19.2 μg/ml of Pa1, 288.5±16.8 μg/ml of Pc1, 309.2±18.2 μg/ml of Pd1, but Pv1 does not. Furthermore, all these species have significantly promoted the growth of the lettuce seedling plants at the range around 32~37% for fresh weight and 10~15% for shoot length enhancement, so that these microbe could be used as a potential bio-fertilizer agents.

• Korean Journal of Microbiology
• /
• v.26 no.3
• /
• pp.230-236
• /
• 1988

The distributions of bacterial numbers and activities were studied bimonthly in 1987, at 3 sites in Lade Paro for elucidating the changes by disturbance of aquatic ecosystem. The total bacterial number was $0.3\times 10^{5}-13.1\times ^{5}$ cells/ml. The geterotrophic bacterial number had the variance from $1.9\times 10^{3}$ CFUs/ml to $3.1\times 10^{4}$CFUs/ml and the variation trend was similar to that of the total bacterial number. The proportions of alpha-glucosidase or beta-glucosidase releasing bacteria showed temporal changes rather than spatial changes. The proportions of phosphatase releasing bacteria had the maximum values, 22.7-83.0%, in July. The electron transpory system activity revealed the variation from $480{\mu}gO_{2}$/l/day to $1696{\mu}gO_{2}$/l/day and hagher values at upper stream and in summer. The degradation fraction by phosphatase was 0.4-9.1%/h and increased with temperature. The maximum value of heterotrophic activity was 8.2%/h in summer. Eventhough the distributions of total bacteria and heterotrophic bacteria were affected by the water disturbance but microbial activities and proportions of the specific enzume releasing bacteria were not affected.

• Journal of the Korean earth science society
• /
• v.24 no.3
• /
• pp.216-233
• /
• 2003

This study delineates the phenomena related with global environmental changes such as global warming, ozone depletion, and El Ni${\tilde{n}}$o/Southern Oscillation (ENSO) noted in the Antarctic. Retreat of ice cliffs, glaciers, and calving of ice shelves indicate the effects of recently aggravated global warming. The ice cliff located at Marian Cove, King George Island, South Shetland Islands off the Antarctic Peninsula has been observed to be retreating faster in the last 7 years than in the previous 38 years since 1956. There are some indications of temperature and precipitation changes associated with ENSO around King Sejong Station. The regression analyses indicate significant trends such as a decrease in the total amount of ozone and an increase in ultraviolet radiation which was seen by a satellite (TOMS-EUV) in September and October which correspond to ozone-hole season over King Sejong Station. Increase of UV radiation due to the ozone depletion in the Antarctic has changed the growth rate of marine organisms. It may also result in changes to the productivity, biomass, and species composition of marine organisms which can affect the whole marine ecosystem. The recent ice-core drilling over Lake Vostok has been reviewed with emphasis on the four cycles of glacial stages over the past 420,000 years. It is time to show more interest in mainland Antarctica through investigations of the coring and vast ice sheet, terrestrial geology, and upper atmospheric sciences in order to understand the past environmental changes and to predict possible changes to the environment in the future.

• Journal of Periodontal and Implant Science
• /
• v.36 no.1
• /
• pp.39-49
• /
• 2006

1. 목 적 이 연구의 목적은 성견의 하악 골 결손부에 이식한 생체 유래 골 이식재에 대한 치조골의 반응을 알아보는 것이다. 2. 연구방법 및 재료 생후 1년 이상 된 성견 4마리의 하악 제2소구치 및 제 4 소구치를 발거하고 발치와에 금원심 폭경 8mm, 협설 폭경 5mm, 치조정에서의 깊이 6mm인 결손부를 형성하였다. 4주간의 자연 치유 후 판막을 형성하여 결손부의 크기를 확인하였다. 각각의 결손부 크기가 일정하도록 수정한 후 '이식재+차폐막'군에는 OCS-B을 이식하고 Bio-gide을 차단막으로 사용한 후 봉합하고 '이식재군'은 OCS-B 이식 후 차폐막 없이 봉합하였으며 '비이식'군은 아무런 처치없이 일차봉합하였다. 수술 4, 6주에 실험동물을 각각 희생시켜 실험부위를 적출하고 비탈회 연마 표본을 제작하여 골 치유 양성을 조직학적 및 조직계측학적으로 관찰하였다. 3. 연구결과 이식재 비이식군 및 이식군 모돼서 별다른 부작용없이 잘 치유되었다. 세 실험군 모두에서 술후 4주에 비교하여 술 후 6주에서의 결손부 산생골 형성량이 증가하였다. 술후 4주 소견에서 비이식군은 결손부 주변부위에서 골이 생성되어 나오는 양상을 보였으며 이식군은 이식재 주변으로 골침착 시작되는 것을 관찰할 수 있었다. 술후 6주 소견에서 비이식군은 결손부 경계부로부터의 지속적인 골 생성을 관찰할 수 있었으며 이식군은 이식재 주변으로 침착된 골의 양이 많아지고 신생골이 가교를 형성하는 것을 관찰할 수 있었다. 4. 결 론 차폐막 유무와 상관없이 OCS-B는 염증반응을 전혀 일으키지 않았으며 우수한 골 전도성을 보였다. 또한 결손부의 형태를 잘 유지하여 골재생을 위한 공간을 확보할 수 있었다. 이는 OCS-B가 골이식재로서의 필요조건을 갖추었음을 확인한 결과이며 보다 장기적인 관찰에서 OCS-B의 흡수 가능성을 확인하는 것이 필요할 것으로 보인다.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.46 no.5
• /
• pp.622-629
• /
• 2017

This study was carried out to investigate the effects of cold maceration and heat treatment prior to alcohol fermentation on the quality characteristics of wine made from Okrang grape cultivar. The results of this study show that alcohol contents of wines increased as fermentation period increased, whereas $^{\circ}Brix$ values decreased. The pH levels of wines ranged from 3.17 to 3.42 while the total acidities of wines ranged from 0.49~0.99%. The free sugar contents of wines tended to decrease as fermentation period increased. In particular, free sugar content of wine pre-treated at low temperature prior to alcohol fermentation slowly. Total polyphenol content of wine heat-treated prior to alcohol fermentation was higher than those of other wines and reached a maximum value after fermentation for 2 days. Campbell Early wine showed the strongest antioxidant effect, measured based on DPPH free radical scavenging activity, followed by Okrang wine pressing after fermentation. These results indicate that pre-treatment before wine fermentation greatly affects wine quality and biofunctional activities.

• Clean Technology
• /
• v.20 no.1
• /
• pp.35-41
• /
• 2014

Batch adsorption studies were carried out for equilibrium, kinetic and thermodynamic parameters for quinoline yellow adsorption by granular activated carbon ($8{\times}30mesh$, $1,578m^2/g$) with varying the operating variables like initial concentration, contact time and temperature. Equilibrium adsorption data were fitted into Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms. From estimated Langmuir constant ($R_L=0.0730{\sim}0.0854$), Freundlich constant (1/n = 0.2077~0.2268), this process could be employed as effective treatment for removal of quinoline yellow. From calculated Temkin constant (B = 15.759~21.014 J/mol) and Dubinin-Radushkevich constant (E = 1.0508~1.1514 kJ/mol), this adsorption process is physical adsorption. From kinetic experiments, the adsorption process were found to confirm to the pseudo second order model with $r^2$ > 0.99 for all concentrations and temperatures. Thermodynamic parameters like activation energy, change of free energy, enthalpy, and entropy were also calculated to predict the nature adsorption. The activation energy value (+35.137 kJ/mol) and enthalpy change (35.03 kJ/mol) indicated endothermic nature of the adsorption process. Entropy change (+134.38 J/mol K) showed that increasing disorder in process. Free energy change found that the spontaneity of process increased with increasing adsorption temperature.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.33 no.2
• /
• pp.711-718
• /
• 2013

Traffic pavement markings are one of primary transportation facilities that provide drivers with various road information directly. Thus, a clear understanding of traffic pavement markings is utmost important to improve traffic safety as well as to establish a proper traffic culture. However, no past studies examined drivers' understanding of traffic pavement markings in Korea. Hence, this study investigated drivers' understanding of traffic pavement markings through an elaborated administrated survey, and analyzed the relationship between various drivers' characteristics and understanding regarding pavement marking via cross-classification table and logistic model. The analysis results show that drivers have limited understanding regarding the purpose of the markings. Specifically, the average understanding of pavement markings is 57.41%: the lowest understanding is 25.88% for yield pavement marking, and the highest understanding is 91.18% for advanced pedestrian crosswalk pavement marking. This study also revealed that the understanding of some pavement markings are somewhat influenced by user group such as drivers with suspended or revoked driver licenses, but the overall understanding of pavement markings are not significantly affected by drivers' characteristics such as gender and driving experiences at ${\alpha}$=0.05. Thus, it might be desirable for policy makers to establish pavement marking-related policies for overall drivers rather than specific drivers.

• Journal of Yeungnam Medical Science
• /
• v.2 no.1
• /
• pp.81-85
• /
• 1985

Management of the small lower ureteral stone has been attempted by either transurethral manipulation or expectant therapy. To date, however, the choice of proper method has depended mostly on clinician's preference, and the effectiveness of the transurethral stone manipulation has remained controversial Herem we evaluated the effectiveness of the transurethral stone manipulation, using with the Dormia dislodger, in 37 patients with lower ureteral stone less than 10mm in greatest diameter. The results are summarized as follows. 1. The overall success rate was 68% (25 of 37 patients); Immediate delivery of the stone was observed in 16 of 37 patients. In another 5 patients the stone was removed at the time when the indwelled ureteral catheter was taken out. In the remaining 4 patients the stone passed spontaneously within a week following the procedure. 2. Higher success rate was observed in smaller stone; 79% in less than 4 mm, 58% in 4-6 mm, and 33% in 6-10mm in it's greatest diameter, respectively. 3. The morbidity rate was 8.1% (3 of 37 patients); In one patient a broken basket was retained In the ureter, which was removed at the time of ureterolithotomy. In another patient a ureteral stricture requiring periodic dilation was complicated. And In the other patient persistent hematuria was observed, which was relieved by conservative management. These results suggest that transurethral manipulation might have to be initially applied to unremittingly painful patients with small lower ureteral stone.

• Proceedings of the KOR-BRONCHOESO Conference
• /
• 1977.06a
• /
• pp.9.1-10
• /
• 1977

Many etiological factors playa significant role in the development of tracheal stenosis; too high tracheostomy (Jackson, 1921), too small stoma (Greisen, 1966), the treatment with respirator using cuffed tube (Pearson et al., 1968; Lindholm, 1966; Bryce, 1972) and infection (Pearson, 1968). Although the incidence has been reduced due to development of surgical technique and antibiotics, the frequency of tracheal stenosis which produces symptoms after tracheostomy ranges from 1.5 per cent (Lindholm, 1967). In the management of the stenosis, mild cases are treated by mechanical dilatation with silicon tube or stent (Schmigelow, 1929; Montgomery, 1965) combined steroid (Birck, 1970), and in the cases of stenosis causes, these removed under the are bronchoscopy. But in severe stenosis, transverse resection with subsequent end-to-end anastomosis has been used in recent years (Pearson et al., 1968). During about 10 years, 1967 to 1977, a total of 23 patients with tracheal stenosis complicated among the 1, 514 tracheostomies have been treated in Severance Hospital. Now, we have obtained following conclusions by means of clinical analysis of 23 cases of tracheal stenosis. 1. The frequency of tracheal stenosis was 23 cases among 1, 514 cases of tracheostomy (1.5%). 2. Under the age of 5, these are 12 cases (52.2 %). 3. The sex incidence was comprised of 18 males and 5 females. 4. The duration of tracheostomy ranges from 4 days to 16 months. 5. The primary diseases requiring tracheostomy were following; central nerve system lesions 11 cases, upper air way obstruction 10 cases, extrinsic respiratory failure 2 cases. 6. Severe wound infections were only 2 cases. 7. The methods of treatment applied to tracheal stenosis were following; closed observation only 5 cases, nasotracheal intubation combined steroid 5 cases, T-tube stent combined steroid 3 cases, fenestration op. 4 cases, revision 4 cases and transverse resection and end-to-end anastomosis 2 cases.