• Tuberculosis and Respiratory Diseases
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• v.45 no.2
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• pp.311-321
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• 1998

Background: Mucoepidermoid carcinoma of the lung arises from submucosal gland of tracheobronchial tree. Histologically, the tumor is composed of mucin-secreting cells, squamous cells, and intermediated cells, which show no particular differentiating characteristics, in varying proportions. The tumor is divided into low grade and high grade depending on the proportion of cells, and the degree of the mitotic activity, cellular necrosis and nuclear pleomorphism. While favorable prognosis of low grade tumor, high grade tumor, which is very difficult to differentiate from adenosquamous carcinoma, has an aggressive clinical course. The tumor is rare, comprising 0.1 to 0.2% of primary lung cancers and 1 to 5% of bronchial adenomas. Method: A retrospective clinical study was done on 17 cases of mucoepidermoid carcinoma. The study investigated the clinical features, radiologic findings, bronchoscopic findings, histology and clinical courses. Results: Age ranged between second to seventh decade with a mean age of 42 years. Twelve out of 17 cases were male. Five out of 17 cases were smokers with a mean 11 pack-years. Common symptoms included dyspnea, cough, hemoptysis, and wheezing. Two out of 17 cases was asymptomatic. Atelectasis or mass was common radiologic finding. Plain chest radiography was normal in one patient whom the tumor was located in upper trachea. Bonchoscopy revealed exophytic mass in 12 cases and nodular infiltrations in 4 cases. One case having solitary pulmonary nodule in the right lower lung was normal on bronchoscopy. Histologically, ten out of 17 cases were low grade, and seven out of 17 cases were high grade. Among 10 patients with low grade tumor,9 patients were performed operation and have been alive without recurrence during a mean follow-up of 30 months. Two out of 7 patients with high grade tumor were performed pneumonectomy and have been alive during a follow-up of 3 and 8 months, respectively. Conclusion: Most of mucoepidermoid carcinoma is located at central airway and is presented symptoms by mucosal irirtation. Although atelectasis or mass is common radiologic finding. chest X -ray can be normal. The histologic grading and the extent of tumor are two most important factors for prognosis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.1
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• pp.77-86
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• 1980

Asking to change the cropping patterns to save the labor and capitals in paddy rice cultivation, the study was intended to know the weed problems under the various possible cultural systems; namely, direct seeding (in broadcast and row), machine transplanting and hand transplanting. Under the conditions as weedy check plots, paddy yields were significantly variated among cropping systems, and the functions of panicle No. and spikelet No. to the yield were neglected, among others. However, the yield and yield components were narrowed among cropping systems, and the function of spikelets number per area was comparatively improved to the others.

• Korean Journal of Agricultural Science
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• v.6 no.1
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• pp.69-95
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• 1979

The study was conducted to search developmental process of plant protection science from review of forty-three hundreds literatures presented since 1900 in Korea and to forecast future statues of the science to be done. About 80 percent of literatures related to plant protection science such as plant pathology, applied entomology, weed science and agricultural pharmacology were collected from publications of agricultural and forestry reseach organizations attached to Office of Rural Development and Office of Forestry. The rest of literatures were mainly collected from Korean Journal of Plant Protection Society and small number of literatures were also collected from publications of the other journals of crop science and thesis collection of agricultural colleges. In Korea, research organizations of plant protection science are divided into two main groups such as exclusive agricultural research organizations and agricultural colleges. It is pointed out that the former contributions to plant protection science are very great compared to those of the latter since 1900. From periodical consideration of developmental process of the science since 1900, the history or the science are divided into three eras such as introduction and sprout of modern plant protection science during the first forty years, distress of the science during the following twenty years including the Second World War and the Korean War and rapid growth of the science after 1961. In spite of long time distress of the science during the Second World War and the Korean War, the researches on plant protection science in post-war have been done twice as many as pre-war. From consideration of the subject plants in researches of plant protection, it is shown that a great many researches on protection of rice plant have been done and occupy 37 percent of plant protection researches since 1900. And also researches on protection of fruit-trees and cash-crops are not so many as those of rice plant but have been done in noticeable numbers. In fact, researches on protection of fruit-trees and cashcrops were the most important subjects of plant protection researches in pre-war while those of rice plant were the most important subjects after 1930, particulary in post-war. From consideration of contents of plant protection researches, it is said that more fundamental researches than applied ones such as practical control methods of diseases, insect pests and weeds were done in pre-war while more applied researches than fundamental ones were done in post-war, Among applied researches, those of chemical control were the most important subjects. Researches on disease and insect-pest resistance have been done in both pre-war and post-war while researches on forecasting of disease and insect-pest and race of plant pathogens have been done in post-war. And also researches on weed control mainly have been done after 1960. Researches on agricultural chemicals for control of diseases, insect pests and weeds still belong to a new field which must be expected in future, and there is nothing to notice with the exception of practical application of agricultural chemicals introduced from foreign countries. Some of important researches on diseases and insect pests were discussed in relation to developmental process of plant protection science in Korea since 1900. In future, researches on plant protection will be develop to the direction supporting importance of integrated control for plant protection. Therefore, it is pointed out that security of highly educated and trained scientists with enlargement of reseach fields of plant protection science are necessary and role of agricultural colleges for future development of the science must be emphasized.

• KSBB Journal
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• v.20 no.4
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• pp.253-259
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• 2005

This study was accomplished using attached $A^2/O$ process that contains nonsurface-modified and surface-modified polyethylene media inside the Anaerobic/Anoxic, Oxic tank, respectively. We could make the hydrophobic polyethylene media have hydrophilic characteristics by radiating ion beam on the surface of the media. The objectives of this study is to investigate the removal efficiencies of the organics and nitrogen when the step feed ratio of raw wastewater into anaerobic and anoxic tank is changed. In this case, we assumed that the denitrification rate can be improved because the nitrifiers in anoxic tank can perform denitrification using RBDCOD instead of artificial carbon sources (for example, methanol, etc.). The wastewater injection rate into anaerobic/anoxic tank was set up by the ratio of 10 : 0, 9 : 1, 8 : 2, 6 : 4, and the results of BOD removal efficiency showed similar trends with $93.3\%,\;92.6\%,\;92.4\%\;and\;91.6\%$, respectively. But the BOD removal efficiency (utilization of the organics) in the anoxic tank was in the order of 9 : 1 $(84.8\%)$, 10 : 0 $(77.0\%)$, 8 : 2 $(75.3\%)$, and 6 : 4 $(61.1\%)$. The T-N removal efficiency was most high when the ratio is 9 : 1 $(67.4\%)$, and other conditions, 10 : 0, 8 : 2, 6 : 4, showed $61.3(\%),\;60.7\%,\;55.5\%$, respectively; the ratio 6 : 4 was found to be lowest T-N removal efficiency, lower than the ratio 9 : 1 by $12\%$. Though the nitrification rate of the ratio 10 : 0, 9 : 1, and 8 : 2 showed similar levels, the ratio 6 : 4 showed considerable inhibition of nitrification, ammonia was the great portion of the effluent T-N. The advantages of this process is that this process is cost-saving, and non-toxic methods than injecting the artificial carbon source.

• Korean Journal of Environmental Agriculture
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• v.37 no.4
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• pp.268-276
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• 2018

BACKGROUND: In the month of January 2018, fine dust alerts and warnings were issued 36 times for $PM_{10}$ and 81 times for PM2.5. Air quality is becoming a serious issue nation-wide. Although interest in air-purifying plants is growing due to the controversy over the risk of chemical substances of regular air-purifying solutions, industrial spread of the plants has been limited due to their efficiency in air-conditioning perspective. METHODS AND RESULTS: This study aims to propose a vegetation-based bio-filter system that can assure total indoor air volume for the efficient application of air-purifying plants. In order to evaluate the quantitative performance of the system, time-series analysis was conducted on air-conditioning performance, indoor air quality, and comfort index improvement effects in a lecture room-style laboratory with 16 persons present in the room. The system provided 4.24 ACH ventilation rate and reduced indoor temperature by $1.6^{\circ}C$ and black bulb temperature by $1.0^{\circ}C$. Relative humidity increased by 24.4% and deteriorated comfort index. However, this seemed to be offset by turbulent flow created from the operation of air blowers. While $PM_{10}$ was reduced by 39.5% to $22.11{\mu}g/m^3$, $CO_2$ increased up to 1,329ppm. It is interpreted that released $CO_2$ could not be processed because light compensation point was not reached. As for the indoor comfort index, PMV was reduced by 83.6 % and PPD was reduced by 47.0% on average, indicating that indoor space in a comfort range could be created by operating vegetation-based bio-filters. CONCLUSION: The study confirmed that the vegetation-based bio-filter system is effective in lowering indoor temperature and $PM_{10}$ and has positive effects on creating comfortable indoor space in terms of PMV and PPD.

• Food Science and Industry
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• v.55 no.2
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• pp.188-202
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• 2022

In the insect industry, as the scope of application of insects is expanded from pet insects and natural enemies to feed, edible and medicinal insects, the demand for quality control of insect raw materials is increasing, and interest in securing the safety of insect products is increasing. In the process of expanding the industrial scale, controlling the temperature and humidity and air quality in the insect breeding room and preventing the spread of pathogens and other pollutants are important success factors. It requires a controlled environment under the operating system. European commercial insect breeding facilities have attracted considerable investor interest, and insect companies are building large-scale production facilities, which became possible after the EU approved the use of insect protein as feedstock for fish farming in July 2017. Other fields, such as food and medicine, have also accelerated the application of cutting-edge technology. In the future, the global insect industry will purchase eggs or small larvae from suppliers and a system that focuses on the larval fattening, i.e., production raw material, until the insects mature, and a system that handles the entire production process from egg laying, harvesting, and initial pre-treatment of larvae., increasingly subdivided into large-scale production systems that cover all stages of insect larvae production and further processing steps such as milling, fat removal and protein or fat fractionation. In Korea, research and development of insect smart factory farms using artificial intelligence and ICT is accelerating, so insects can be used as carbon-free materials in secondary industries such as natural plastics or natural molding materials as well as existing feed and food. A Korean-style customized breeding system for shortening the breeding period or enhancing functionality is expected to be developed soon.

• Korean Journal of Environmental Biology
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• v.41 no.3
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• pp.325-334
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• 2023

The invasive red swamp crayfish, Procambarus clarkii, is native to south-central United States and northeastern Mexico. Recently, it has been being spreading in the wild in South Korea. However, its primary sources, introduction routes, establishment, and expansion in South Korea remain unclear. Here, we analyzed genetic diversity and population genetic structures of its domestic natural populations during early invasion, commercial stock from local aquaria (a suspected introduction source), and original United States population using mitochondrial COI gene sequences for 267 individuals and eight microsatellite markers for 158 individuals. Natural and commercial populations of P. clarkii showed reduced genetic diversity (e.g., haplotype diversity and allelic richness). The highest genetic diversity was observed in one original source population based on both genetic markers. Despite a large number of individuals in commercial aquaria, we detected remarkably low genetic diversity and only three haplotypes among 226 individuals, suggesting an inbred population likely originating from a small founder group. Additionally, the low genetic diversity in the natural population indicates a small effective population size during early establishment of P. clarkii in South Korea. Interestingly, genetic differentiation between natural populations and the United States population was lower than that between natural populations and aquarium populations. This suggests that various genetic types from the United States likely have entered different domestic aquariums, leading to distinct natural populations through separate pathways. Results of our study will provide an insight on the level of genetic divergence and population differentiation during the initial stage of invasion of non-indigenous species into new environments.

• The Korean Journal of Air & Space Law and Policy
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• v.18
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• pp.135-183
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• 2003

Aerospace force is a determining factor in a modem war. The combat field is expanding to space. Thus, the legitimacy of establishing aerospace force is no longer an debating issue, but "how should we establish aerospace force" has become an issue to the military. The standard limiting on the military use of space should be non-aggressive use as asserted by the U.S., rather than non-military use as asserted by the former Soviet Union. The former Soviet Union's argument is not even strongly supported by the current Russia government, and realistically is hard to be applied. Thus, the multi-purpose satellite used for military surveillance or a commercial satellite employed for military communication are allowed under the U.S. principle of peaceful use of space. In this regard, Air Force may be free to develop a military surveillance satellite and a communication satellite with civilian research institute. Although MTCR, entered into with the U.S., restricts the development of space-launching vehicle for the export purpose, the development of space-launching vehicle by the Korea Air Force or Korea Aerospace Research Institute is beyond the scope of application of MTCR, and Air Force may just operate a satellite in the orbit for the military purpose. The primary task for multi-purpose satellite is a remote sensing; SAR sensor with high resolution is mainly employed for military use. Therefore, a system that enables Air Force, the Korea Aerospace Research Institute, and Agency for Defense Development to conduct joint-research and development should be instituted. U.S. Air Force has dismantled its own space-launching vehicle step by step, and, instead, has increased using private space launching vehicle. In addition, Military communication has been operated separately from civil communication services or broadcasting services due to the special circumstances unique to the military setting. However, joint-operation of communication facility by the military and civil users is preferred because this reduces financial burden resulting from separate operation of military satellite. During the Gulf War, U.S. armed forces employed commercial satellites for its military communication. Korea's participation in space technology research is a little bit behind in time, considering its economic scale. In terms of budget, Korea is to spend 5 trillion won for 15 years for the space activities. However, Japan has 2 trillion won annul budget for the same activities. Because the development of space industry during initial fostering period does not apply to profit-making business, government supports are inevitable. All space development programs of other foreign countries are entirely supported by each government, and, only recently, private industry started participating in limited area such as a communication satellite and broadcasting satellite, Particularly, Korea's space industry is in an infant stage, which largely demands government supports. Government support should be in the form of investment or financial contribution, rather than in the form of loan or borrowing. Compared to other advanced countries in space industry, Korea needs more budget and professional research staff. Naturally, for the efficient and systemic space development and for the prevention of overlapping and distraction of power, it is necessary to enact space-related statutes, which would provide dear vision for the Korea space development. Furthermore, the fact that a variety of departments are running their own space development program requires a centralized and single space-industry development system. Prior to discussing how to coordinate or integrate space programs between Agency for Defense Development and the Korea Aerospace Research Institute, it is a prerequisite to establish, namely, "Space Operations Center"in the Air Force, which would determine policy and strategy in operating space forces. For the establishment of "Space Operations Center," policy determinations by the Ministry of National Defense and the Joint Chief of Staff are required. Especially, space surveillance system through using a military surveillance satellite and communication satellite, which would lay foundation for independent defense, shall be established with reference to Japan's space force plan. In order to resolve issues related to MTCR, Air Force would use space-launching vehicle of the Korea Aerospace Research Institute. Moreover, defense budge should be appropriated for using multi-purpose satellite and communication satellite. The Ministry of National Defense needs to appropriate 2.5 trillion won budget for space operations, which amounts to Japan's surveillance satellite operating budges.