저항을 이용한 프로판-공기 혼합가스의 점화한계 개선에 관한 연구

이춘하,오종용,옥경재,지승욱,이광식,심광렬 한국화재소방학회 2004 한국화재소방학회논문지 Vol.18 No.1

본 논문은 IEC형 불꽃점화 시험장치를 이용하여 저압 유도회로의 최소 점화한계를 프로판-공기 5.25 Vol.%의 혼합 가스에 대하여 실험적으로 구하였으며, 또한 유도회로의 인덕턴스 L에 안전소자로서 저항을 병렬접속하였을 경우 프로판-공기 5.25 Vol.%의 혼합 가스에 대한 점화한계 개선효과를 관찰하였다. 그 결과, 최소 점화한계는 전류의 크기에 따라 좌우되었다 또한, 전원으로부터 공급되는 에너지는 인덕턴스에 우선 축적되고. 그 초과분의 에너지가 폭발성 가스의 점화원으로 작용하였다. 점화한계 개선효과는 인덕턴스가 300 mH일 때, 최고 330%의 개선효과가 나타났으며 인덕턴스가 클수록 점화한계 개선효과가 크게 나타났다. 또한 병렬로 접속한 저항의 크기가 적을수록 점화한계 개선 효과가 크다. 본 연구결과는 본질안전 방폭형 전기기기의 연구개발을 위한 기본자료로 활용할 수 있을 뿐만 아니라 이들 기기의 방폭성능에 대한 시험자료로도 활용이 가능할 것으로 사료된다. This paper describes the minimum ignition limits for propane-air 5.25 Vol.% mixture gases in low voltage inductive circiuts. The improved effects on the ignition limit are studied by parallel safety components(resistors) for propane-air 5.25 Vol.% mixture gas in low voltage inductive circuits. The experimental devices used in this test are the IEC type spark ignition test apparatus. The minimum ignition limits are controlled by the values of current in inductive circuit. Energy supplied from elect source is first accumulated at the inductance, it's extra energy is working as ignition source of the explosive gas. The improved effects on the ignition limit are respectively obtained as the maximum rising rate of 330% by composing parallel circuits between inductance and resistor as compared with disconnecting inductance with the safety components. The more values of inductance increase the higher improved effects of ignition limit rise. The less values of resistor the higher improved effects of ignition limit rise. It is considered that the result can be used for not only data for researches and development of intrinsically safe explosion-proof machines which are applied equipment and detectors used in dangerous areas but also for datum for its equipment tests.

전기분해에 의한 계면활성제 함유 폐수처리에 관한 연구

이춘식,정병윤,하태명,박현건 진주산업대학교 농업기술연구소 2001 農業技術硏究所報 Vol.14 No.-

This study was carried out to investigate the purification effect of wastewater included LAS by electrolysis treatment system. Wastewater included LAS treated electrolysis treatment process, temperature of inner treated system were high than those of this raw wastewater, temperature change was electrolysis oxidation of LAS wastewater both cathode and anode. Electrolysis oxidation was oxidized LAS by oxidants of chlorine and ozone, on the time, according to the result development of treated efficiency on electrolysis contact time.

알레르기 환자에서 특이알레르겐 항체 양성율과 관련요인

이선화,남해선,이성수,안현철,황규윤,박준수,,박춘식 순천향의학연구소 2002 Journal of Soonchunhyang Medical Science Vol.8 No.2

Recently, allergic diseases are very prevalent in Korea, resulting in physical and economic losses during the life. It is well-known that the principle therapy is identification, eradication, and desensitization of allergens. There are many allergic diagnostic tools for identification of specific-allergens. However, none of them is satisfied with its efficiency due to lack of validity. Recently MAST-CLA has been widely used in the allergic clinical fields because of its simplicity and simultaneous identification of allergens. This study was designed to determine the positivity of allergen-specific antibodies using MAST-CLA in patients with allergic diseases, and evaluate the efficacy for allergen detection, compared to results of skin prick test. During June 2000 - September 2001, 325 study subjects visited Soonchunhyang University Chunan Hospital for the evaluation of allergic problems. Among them, 289 subjects were diagnosed with allergic disease and included for the study. Thirty four subjects visited children's allergic unit were evaluated specific allergens using a skin prick test at the same time. Our result as follows; 1. The positive rates of allergen-specific antibodies and total IgE were 51.2% and 73.4%, retrospectively. 2. There was significant difference in positive rate in age group, showing highest in teen ages(73.6%), but insignificant difference in sex in allergen-specific antibodies. 3. The positive rate was 60.4% in allergic rhinitis, 51.3% in allergic dermatitis, 46.9% in bronchial asthma, and 39.1% in urticaria in order(P=0.073). 4. Significant difference in month or season was observed, with highest rate in April(78.1%) and May(72.1%). The highest season was in spring(62.7%), and then summer(52.8%), fall(50.3%), and winter(41.4%) in order (P=0.04). 5. The three highest allergen-specific antibodies were D. pteronyssinus(39.3%), D. farinae(38.3%), and house dust(24.3%) in Korean inhalant pannel, However, in food pannel types of allergen-specific antibody were different as D. farinae(18.5%), Alternaria(18.5%), house dust(17.3%). 6. There were significant agreements between MAST-CLA and Skin prick test (D. farianae Kappa=0.636;D. pteronyssinus Kappa=0.78, both P<0.001) In conclusion, MAST-CLA could detect allergen-specific antibodies in patients with allergic diseases as a simple and valid tool of screening of allergy. Especially, it could be a useful measure of multiple allergens simultaneously in children However, more detailed allergens and valid assay for unmeasured allergens should be identified for Korean-specific allergens.

무기이온을 광증감제로 사용한 유해물질의 광분해

이춘식,김영희,박현건 진주산업대학교 1999 산업과학기술연구소보 Vol.- No.6

Photodegradation of benzene, carbaryl and aldrin were conducted with persulfate, nitrate and nitrite ion as sensitizers in aqueous solution. Persulfate and nitrate ions were proved to be effective to enhance the photodegradation of hazardous compounds. The sensitizing effect increased with increasing persulfate concentration, while nitrate ion showed the greatest sensitizing effect at 5㎎/l. In the case of the nitrite ion, no significant enhancement effect was observed, on the contrary, inhibited the photodegradation of hazardous compounds. With increasing nitrite concentration, photodegradation of hazardous compounds ran through a maximum value and decreased there after with increasing nitrite concentration.

제주도지방 우박 현상시 대기 구조 분석

이춘식 조선대학교 환경공해연구소 2004 環境公害硏究 Vol.18 No.-

It was observed 35 times of hail from 1975 to 2003 during 28 years, and it was produced in late autumn and winter 89% of them, and hail incidence was the highest immediately after sunrise and sunset. Size of hail was fewer than 0.5cm about 50%, and it was not observed more than 0.8cm, in Cheju. Hail is dropped in Cheju because formed cloud according as air temperature difference between sea and atmosphere when cold atmosphere passes west coast when Siberian air mass(cP) expanded to Cheju in winter, and becoming updraft more lustily at Mt. Halla's(1,950m) windward side. As a result of research on pressure change when there was hail over 0.6cm, it was analyzed that hail drops about 10 hours later after the pressure has dropped and 6 hours later after the lowest pressure recorded. Also, hail is happened more at sunset or sunrise, which it change each other the land sea breeze. Usually in summer, Cheju is influenced by mT. Therefore, instability of air is not strong because there is not cold advection and cold air flowed from the sea to the land make the instability weaken. Therefore, in Cheju, it is researched that hail is not happened because ice crystals are hard to grow hail in summer.

軟弱地盤 壓密特性과 沈下豫測

이재식,류제천,김송만,박춘수 충남대학교 산업기술연구소 2001 산업기술연구논문집 Vol.16 No.1

Recently, developed countries have brought about a considerable increase in the study of soft ground for the reasons of policy on farming protection, key industry and sightseeing development since the middle of the nineteenth century, particularly 1950s. In spite of the long and copious experience associated with these types of construction, the constructions of soft ground still have many delicate problems. In general, problems of soft ground related to stability are probably to meet settlements on the various circumstances. In order to accelerate the rate of consolidation settlement and gain a required shear strength for a given soft ground, the preloading technique combined with a vertical drainage system has been widely applied. In this paper, laboratory tests have analyzed to change the soil parameters that executed the plan of stage construction. The void ratio and water content of the clay decreases and the strength of soft ground rises during consolidation period. In order to predict of magnitude, rate of settlement and pore pressure dissipation under embankment of loading on drainage-installed soft ground, consolidation settlement prediction methods such as Asaoka method, curve fitting method, TAN method and Hyperbolic method applied to gain final consolidation settlement from the field settlement data. The Reliability analysis of consolidation settlement prediction methods made use of additional settlement data. Sequentially, it has been found that Hyperbolic method can appropriately predict the consolidation behavior of drainage-installed soft ground of Yangsan Mulgum.

수소공여체에 의한 동력학적탈질연구

이춘식,박현건,전기일 진주산업대학교 1995 論文集 Vol.34 No.-

Results of examined Kinetic according to varied each of hydrogen donor of nitrate containing synthetic wastewater by anaerobic process were summarized as follow: 1. Value of specific growth rate(K) were K_1= 0.931, K_2=0.885, K_3=0.917, so Yield coefficient(Y), Endogenous respiration coefficient(Kd) were Y_1=234.8 gVSS/gNO_3-N, Kd_1=0.153 hr^-1, Y_2=234.35 gVSS/gNO_3-N, Kd_2=0.25 hr^-1, Y_3=247.68 gVSS/gNO_3-N, Kd_3=0.17 hr^-1.

Aldrin의 광증감 분해에 관한 연구

이춘식,김영희,김성우,이동근 경상대학교 환경보전연구소 1999 環境保全硏究所報 Vol.7 No.-

Sensitized photooxidation of aldrin was carried out using anions as sensitizers. Persulfate, nitrate ions were proved to be effective to enhance the photooxidation of aldrin. Nitrite ion was inhibited to the photooxidation of aldrin. In the case of sulfate and chloride ion, however, no significant enhancement effect was observed. The sensitizing effect increased with increasing persulfate and nitrate concentration. Nitrite ion was oxidated to nitrate by photolysis reaction. The sensitized effect decreased with increasing nitrite concentration.

광촉매와 광증감제를 이용한 유기염소화합물의 광분해에 관한 연구

이춘식,김영희,박승조 동아대학교 환경문제연구소 1998 硏究報告 Vol.21 No.2

Phetodegradation of organic chlorocompounds(chloroform, trichloroethylene, chlorobenzene) in aqueous suspension of several semiconductors(TiO₂, ZnO, SnO₂) and in aqueous solutions of inorganic anion(S₂O_(8)^(2-), NO₃^(-), NO₂^(-)) have been studied. Photocatalytic degradation of organic chlorocompounds was increased in the order of SnO₂ < ZnO < TiO₂. which irradiated by 450W medium pressure Hg lamp through pyex filter Unsaturated and aromatic hydrocarbon was degradated more effectively than saturated hydrocarbon. When inorganic anions was added to reaction solution as photosensitizer, photodegradation of organic chlorocompounds was much increased bs- S₂O_(8)^(2-), but little affected by NO₃^(-) or NO₂^(-), which irradiated by 15W low pressure Hg lamp.

자궁경부종양에서 Cathepsin-D 표현의 의의

이춘희,김세진,전상식,이택후,조영래,채종민 경북대학교 병원 1997 경북대학교병원의학연구소논문집 Vol.1 No.1

Various clinical and histopathologic characteristics are currently used to obtain prognostic information about cervical carcinoma, but they do not predict the outcome for any individual patients. Thus, there is a need to identify additional tumor characteristics that are able to predict more accurately the outcome for an individual patient with cervical cancer. In this study, we explored the relationship between cathepsin-D expression and progression of the cervical neoplasia, the correlation between response to neoadjuvant chemotherapy and cathepsin-D expression, and we investigated if tumor cell cathepsin-D expression could serve as a prognostic factor in cervical carcinoma. Tumor tissues were obtained from 14 patients with cervical intraepithelial neoplasia and 52 patients with squamous cell carcinoma of the cervix. Cathepsin-S expression was identified by immunohistochemical methods using monoclonal antibody cathepsin-D (BioGene). Positive cathepsin-D immunoreaction in greater than 30% of carcinoma cells was scored as high expression. High cathepsin-D expression was seen in 15 of 52 invasive cancer but was absent in cervical intraepithelial neoplasia. It was shown that cathepsin-D expression was independent of the rumor grade, tumor size, lymph node involvement, depth of invasion, parametrial invasion, and response to chemotherapy. In disease free survival analysis by log-rank test, cathepsin-D expression was not significantly associated with survival. These results show that cathepsin-D expression is not a clinically useful adjunct to assessment of prognosis in invasive squamous cell carcinoma of the cervix.