젖소 사육에서 탄소 순환 체계에 관한 고찰 연구

김기연,고한종,김치호,최은규,김종구,유영선,김현태,Kim, Ki-Youn,Ko, Han-Jong,Kim, Chi-Ho,Choi, Eun-Gyu,Kim, Joung-Ku,Ryou, Young-Sun,Kim, Hyeon-Tae 한국축산환경학회 2012 축산시설환경학회지 Vol.18 No.1

젖소를 사육하는 유우농가 마을을 대상으로 선행 국내/외 문헌자료들에 대한 고찰을 통해 탄소 유입과 배출에 따른 각 부문별 발생량 원단위에 대한 다음과 같은 결론을 도출하였다. 1. 젖소 사육과정에서 탄소 유입에 대한 발생량 원단위는 젖소의 사료 섭취에 의한 탄소 유입(${\fallingdotseq}$ 5.9 ton C/head/year), 젖소 분뇨 퇴비를 초지로 환원시 탄소 유입(${\fallingdotseq}$ 2.3 ton C/head/year), 초지가 함유하고 있는 유기탄소(${\fallingdotseq}$ 318g C/$m^2$/year), 사료작물이 함유하고 있는 유기탄소(${\fallingdotseq}$ 145 g C/$m^2$/year) 및 광합성에의한 대기 중 $CO_2$의 초지 사료작물 흡수(${\fallingdotseq}$ 17 g C/$m^2$/year)로 정리할 수 있다. 2. 젖소 사육과정에서 탄소 배출에 대한 발생량 원단위는 젖소 호흡 및 트림에 의한 대기 중으로 $CO_2$와 $CH_4$ 배출(${\fallingdotseq}$ 2,9 ton C/head/year), 젖소 분뇨내 유기탄소 분해에 의한 대기 중으로 $CO_2$와 $CH_4$ 배출(${\fallingdotseq}$ 0.4 ton C/head/year), 초지에서 대기 중으로의 $CO_2$ 배출(${\fallingdotseq}$ 440 g C/$m^2$/year), 및 초지 내 유기탄소의 지하수 용출(${\fallingdotseq}$ 0)로 정리 할 수 있다. The first objective of this study is to estimate emission coefficient of organic carbon regarding its inflow and discharge for dairy farm through reviewing domestic and foreign literature published or reported previously. Its second objective is to provide fundamental data to establish carbon cycle system related to livestock production. Based on literature review, emission coefficients by inflow of organic carbon into dairy farm were 5.9 ton C/head/year for feedstuff ingestion by milk cow, 2.3 ton C/head/year for recycling manure compost of milk cow to grassland, 318 g C/$m^2$/year for contents in grassland, 145 g C/$m^2$/year for contents in fodder crop, and 17 g C/$m^2$/year for $CO_2$ uptake by fodder crop, respectively. on the other hand, emission coefficients by discharge of organic carbon from dairy farm were 2,9 ton C/head/year for emission of $CO_2$ and $CH_4$ by respiration and burp of milk cow, 0.4 ton C/head/year for emission of $CO_2$ and $CH_4$ by decomposition of organic carbon in manure of milk cow, 440 g C/$m^2$/year for emission of $CO_2$ from grassland, and 0 for elution of organic carbon in grassland into underground water, respectively.

복합식 공기청정기의 물리적 및 생물학적 입자상 물질의 제거 효과

김기연,김치년,김윤신,노영만,이철민,Kim, Ki-Youn,Kim, Chi-Nyon,Kim, Yoon-Shin,Roh, Young-Man,Lee, Cheol-Min 한국환경보건학회 2006 한국환경보건학회지 Vol.32 No.5

There was no significant difference in the CADR (Clean Air Delivery Rate) between physical aerosols, NaCl and smoke, and biological aerosols, airborne MS2 virus and P. fluorescens, which implicate that the hybrid-type of air purifier, applying the unipolar ion emission and the radiant catalytic ionization, imposed identical reduction effect on both physical aerosol and bioaerosol. Ventilation decreases the efficiency of air cleaning by unipolar ionization because high ventilation diminishes the particle concentration reduction effect. The particle removal efficiency decreases with increase in the chamber volume because of the augmented ion diffusion and higher ion wall loss rate. Particle size affects the efficiency of air ionization. The efficiency is high for particles with very small diameter because reduction of charge increases with particle size. If there is no increasing supply of ions, the efficiency of air cleaning by unipolar ionization increases with respect to initial concentration of particles because of the large space charge effect at high particle concentration and amplified electric field.

여름철 그을린 피부손질

김기연,Kim, Gi-Yeon 한국건강관리협회 1985 건강소식 Vol.9 No.8

불타는 태양은 우리와 함께하고 여름의 낭만이 우리를 손짓하지만 여름의 낭만이 우리를 손짓하지만 여름을 맞이한 피부는 높은 기온과 강한 자외선으로 피지 분비가 많아지고 피부내 자연보습성분인 NMF와 수분이 감소되어, 피부는 거칠어 집니다.

가축분뇨 자원화시설에서 발생되는 암모니아와 황화수소의 계절별 현장 평가

김기연,Kim, Ki Youn 한국축산환경학회 2015 한국축산시설환경학회지 Vol.21 No.2

The objective of this study is to measure the levels of ammonia and hydrogen sulfide in livestock manure composting facility according to seasonal condition. Mean concentrations of ammonia in livestock manure composting facility were 84.3 (${\pm}15.2$) ppm for spring, 115.2 (${\pm}34.7$) ppm for summer, 76.2 (${\pm}18.9$) ppm for autumn, and 38.1 (${\pm}10.4$) ppm for winter, respectively. Based on the results obtained from this study, the seasonal levels of ammonia in livestock manure composting facility were highest in summer followed by autumn, spring and winterroom (p<0.05). Mean concentrations of hydrogen sulfide in livestock manure composting facility were 7.46 (${\pm}2.24$) ppm for spring, 9.42 (${\pm}2.82$) ppm for summer, 8.15 (${\pm}3.06$) ppm for autumn, and 10.18 (${\pm}4.11$) ppm for winter, respectively. The livestock manure composting facility showed the highest levels of hydrogen sulfide in winter followed by summer, autumn and spring. However, there was no significant difference of hydrogen sulfide concentration among seasons (p>0.05). 본 연구의 목적은 가축분뇨 자원화시설에서 배출되는 주요 악취물질을 대상으로 계절별 현장 방문 조사를 통해 전반적인 악취발생 현황을 파악하고 가축분뇨 자원화시설 운용시 효율적으로 적용될 수 있는 악취 저감대책을 설정하기 위한 기초 데이터 구축이다. 횡형 로터리 (Rotary) 교반방식의 퇴비화시설 내부의 암모니아 발생 농도는 봄철은 84.3 (${\pm}15.2$) ppm, 여름철은 115.2 (${\pm}34.7$) ppm, 가을철은 76.2(${\pm}18.9$) ppm, 겨울철은 38.1 (${\pm}10.4$) ppm으로 측정되었다. 분석 결과 여름철이 가장 높은 것으로 나타났고, 다음으로 가을철 > 봄철 > 겨울철인 것으로 조사되었다 (p<0.05). 반면 황화수소 발생 농도는 봄철은 7.46(${\pm}2.24$) ppm, 여름철은 9.42 (${\pm}2.82$) ppm, 가을철은 8.15 (${\pm}3.06$) ppm, 겨울철은 10.18 (${\pm}4.11$) ppm으로 측정되었다. 분석 결과 겨울철이 가장 높은 것으로 나타났고, 다음으로 여름철 > 가을철 > 봄철인 것으로 조사되었으나, 계절별 통계적 차이는 유의하지 않은 것으로 조사되었다 (p>0.05).

반복 하중이 Full veneer crown의 유지력에 미치는 영향에 관한 연구

김기연,이선형,정헌영,양재호,허성주,Kim, Ki-Youn,Lee, Sun-Hyung,Chung, Hun-Young,Yang, Jae-Ho,Heo, Seong-Joo 대한치과보철학회 2000 대한치과보철학회지 Vol.38 No.5

Dislodgement of a crown or extension bridge and the loosening of a retainer of a bridge is a serious clinical problem in fixed restoration. Generally these problems are considered to be associated with deformation of the restoration. During biting, the restoration is subjected to complex forces and deforms considerably within the limit of its elasticity. Deformation of the restoration under the occlusal force induces excessive stress in the cement film, which then leads to the cement fracture. Such a fracture may eventually cause loss of the restoration. Because most of the past retention tests for full veneer crown were done without fatigue loading, they were not exactly simulating intraoral environment. And the purpose of this study was to evaluate the effect of cyclic cantilever loading on the retentive strength of full veneer crowns depending on different type of cements and taper of prepared abutment. Steel dies with $8^{\circ}\;or\;16^{\circ}$ convergence angle were fabricated through milling and crowns with the same method. These dies and crowns were divided into 8 groups. Group 1 : $16^{\circ}$ taper die, cementation with zinc phosphate cement, without loading Group 2 : $16^{\circ}$ taper die, cementation with zinc phosphate cement, with loading Group 3 : $8^{\circ}$ taper die, cementation with zinc phosphate cement, without loading Group 4 : $8^{\circ}$ taper die, cementation with zinc phosphate cement, with loading Group 5 : $16^{\circ}$ taper die, cementation with Panavia 21, without loading Group 6 : $16^{\circ}$ taper die, cementation with Panavia 21, with loading Group 7 : $8^{\circ}$ taper die, cementation with Panavia 21 without loading Group 8 : $8^{\circ}$ taper die, cementation with Panavia 21, with loading After checking the fit of die and crown, the luting surface of dies and inner surface of crowns were air-abraded for 10 seconds. The crowns were cemented to the dies, with cements mixed according to the manufacturer's recommendations. A static load of 5kg was then applied for 10 minutes with static loading device. Twenty-four hours later, group 1, 3, 5, 7 were only thermocycled, group 2, 4, 6, 8 were subjected to cyclic loading after thermocycling. Retentive tests were performed on the Instron machine. From the finding of this study, the following conclusions were obtained 1. Panavia 21 showed significantly higher retentive strength than zinc phosphate cement for all groups (p<0.05). 2. There was a significant difference in the retentive strength between $8^{\circ}\;and\;16^{\circ}$ taper for zinc phosphate cement(p<0.05), but no significant difference for Panavia 21 (p>0.05). 3. Cyclic loading significantly decreased the retentive strength for all groups(p<0.05). 4. For zinc phosphate cement, there was 35% reduction of the retentive strength after loading in the $16^{\circ}$ taper die, 25% in the $8^{\circ}$ taper die, and for Panavia 21, 21% in the $16^{\circ}$ taper die, 18% in the $8^{\circ}$ taper die.

환절기의 피부손질

김기연,Kim, Gi-Yeon 한국건강관리협회 1985 건강소식 Vol.9 No.3

여성과 가을, 그리고 아름다운 피부

김기연,Kim, Gi-Yeon 한국건강관리협회 1985 건강소식 Vol.9 No.9

여심의 피부는 가을바람에 피어오른다 낙엽 내음을 싣고 오는 가을바람에 가슴은 설레이고, 만물은 활동을 주춤하는 9월. 그러나 가을바람과 밤낮의 심한 기온차의 심술은 여자의 아름다움을 창조하고자 하는 마음을 시샘하며, 여심의 가슴에 응어리를 만든다.

서울시 일부 지역의 대기 중 부유 진균의 분포 특성

김기연,김대근,Kim, Ki-Youn,Kim, Dae-Keun 한국환경보건학회 2012 한국환경보건학회지 Vol.38 No.5

Objectives: This study was performed to assess based on field investigation the distribution characteristics of airborne fungi in an area of Seongdong-gu, Seoul. Methods: Three sites, a living area, forest and traffic site, were selected for evaluation of monthly level of outdoor airborne fungi. An on-site survey was executed between January 2009 and December 2009. During the experimental period, air sampling was performed every month in the afternoon (2:00 pm-5:00 pm) using a cascade impactor. Results: Outdoor airborne fungi measured in Seoul, Korea over one year showed a concentration range from 850CFU $m^{-3}$ to 15,200CFU $m^{-3}$. The mean respirable fraction of outdoor airborne fungi was 67% compared to total concentration. Regardless of measurement site, there was no significant concentration difference in outdoor airborne fungi between periods of yellow dust and non-yellow dust (p>0.05). There was no significant correlation relationship between outdoor airborne fungi and atmospheric factors such as temperature and relative humidity. The predominant genera of airborne fungi identified were Aspergillus, Cladosporium, Paecilomyces and Penicillium. Conclusion: Monthly levels of outdoor airborne fungi were highest in April and November and lowest in August. In seasonal concentration distribution, the autumn showed the highest level of outdoor airborne fungi, followed by spring, summer and winter. In regional concentration distribution, the highest level of outdoor airborne fungi was generally found in the forest, followed by the living area and traffic site.

시편 제작 방법이 지르코니아 코어와 비니어링 세라믹의 미세 인장결합강도에 미치는 영향

김기연,여인성,김성훈,한중석,이재봉,양재호,Kim, Ki-Yeon,Yeo, In-Sung,Kim, Sung-Hun,Han, Jung-Suk,Lee, Jai-Bong,Yang, Jae-Ho 대한치과보철학회 2011 대한치과보철학회지 Vol.49 No.2

연구 목적: 미세 인장결합강도 측정을 위한 시편 제작 시 발생하는 스트레스가 결합강도에 어떠한 영향을 미치는 지를 알아보고자 하였다. 연구 재료 및 방법: 원통 모양의 지르코니아 블럭을 다이아몬드 디스크를 이용해 디스크 형태로 자른 후 소결하였다. 소결된 지르코니아 디스크에 소성시 수축을 고려한 적당한 크기의 틀을 제작하여 LAVA ceram (3M ESPE, Seefeld, Germany) 도재를 축성한 후 소성하였다. 먼저 그룹 1은 디스크 모양의 시편을 충분히 물을 뿌려가며 다이아몬드 디스크를 이용하여 $1{\times}1{\times}7\;mm^3$의 막대기 모양으로 저속에서 절단하였다 (n = 15). 그룹 2는 같은 방법으로 $1.2{\times}1.2{\times}7\;mm^3$로 자른 후 두꺼운 다이아몬드 디스크를 이용해 $1{\times}1{\times}7\;mm^3$로 트리밍하였다 (n = 15). 그 후 특별히 제작된 지그에 각각의 시편을 core-veneer의 접착면이 오염되지 않도록 조심히 접착한 후 미세 인장결합강도 측정기 (Instron 8848, $Instron^{(R)}$ Co., Norwood, USA)를 이용하여 미세 인장결합강도를 측정하였다. 측정이 끝난 시편은 파절면을 stereomicroscope (MZ6, Leica Microsystems GmbH, Wetzlar, Germany) 로 30배 확대 관찰하여 파절의 종류를 구분하였다. 결과: 지르코니아 코어와 비니어링 세라믹 간의 평균 미세 인장결합강도는 절단만 시행한 그룹은 $28.8{\pm}7.0\;MPa$, 절단 후 트리밍을 한 그룹은 $11.0{\pm}33\;MPa$로 절단후 트리밍을 한 시편이 유의성 있게 결합강도가 낮아진 것으로 나타났다 (P=.00). 결론: 미세 인장결합강도 측정을 위한 시편 제작 시 가능한 한 스트레스를 가하지 않고 미세 시편을 제작하는 것이 중요하다고 사료된다. The aim of this study was to investigate effect of specimen preparation method on the microtensile bond strength of veneering ceramic to zirconia core. Materials and methods: Cylindrical Lava zirconia block (3M ESPE, Seefeld, Germany) was cut into discs using a diamond disc. After sintering, the core specimens were placed in an adjustable mold and veneered with Lava ceram (3M ESPE, Seefeld, Germany). The disc shaped specimen of group 1 was cut into microbars ($1{\times}1{\times}7\;mm^3$) using a low speed diamond disc under water cooling (n = 15). The specimen of group 2 was cut into microbars ($1.2{\times}1.2{\times}7\;mm^3$) in the same way. Whereafter the microbars were trimmed ($1{\times}1{\times}7\;mm^3$) using a thick diamond disc under water cooling (n = 15). The microtensile bond strength was tested in a microtensile tester (Instron 8848, $Instron^{(R)}$ Co., Norwood, USA). Fractured microtensile specimens were analyzed under a stereomicroscope (MZ6, Leica Microsystems GmbH, Wetzlar, Germany) at magnification ${\times}30$. Results: The microtensile bond strength of group 1 ($28.8{\pm}7.0\;MPa$) was significantly higher than group 2 ($11.0{\pm}33\;MPa$) (P=.00). Conclusion: It appears advisable to avoid the trimming action, especially high strength ceramic specimens.

인터넷전화 수용 결정요인과 사용자 연령 및 경험 변수의 조절효과 분석

김기연,이덕선,설정선,이봉규,Kim, Ki-Youn,Lee, Duk-Sun,Seol, Jeong-Seon,Lee, Bong-Gyou 한국정보처리학회 2009 정보처리학회논문지D Vol.16 No.6

본 연구의 목적은 첫째, 인터넷전화(Voice over Internet Protocol)의 사용자 수용에 미치는 결정요인을 정의하고, 둘째, 수용 이론들의 통합모형인 UTAUT를 기저모형으로 하여, 성과기대감, 사회적 영향, 노력기대감, 사용촉진조건, 행위의도와 사용행위 등의 잠재변수 간의 복합적인 인과관계를 검증하는 것이다. 셋째, 비용기대감 변수를 새롭게 정의하여 연구가설에 포함하였고, 각 변수들 간의 경로에 영향을 주는 조절변수로서 사용자 연령, 성별, 경험기간의 조절효과를 분석하였다. 또한, VoIP의 실제 사용자 641명을 표본 조사함으로써, 행위의도와 사용행위 변수 간의 개념적 차이를 명확히 구분하여 보다 정확한 분석 결과의 향상을 도모하였다. 사용자 수용에 대한 기존 연구들은 사용행위 변수를 검증할 때, 실제 사용자뿐만 아니라 긍정적인 행위의도를 가진 미래의 잠재적 사용자를 포함시키는 사례가 많았다. 분석 결과, 제시한 모든 연구가설이 채택되었으며, 조절효과에서 연령이 성과기대감, 사회적 영향과 행동의도 간에, 경험기간은 사용촉진조건, 행위의도와 사용행위 간에 정의 관계가 성립하였다. The purpose of this study is to define determinants of VoIP user acceptance and to verify significant causality among latent variables - performance expectancy, effort expectancy, cost expectancy, social influence, facilitating conditions, behavioral intend, use behavior - based on UTAUT model. We presented the expanded hypotheses including the new factor, cost expectancy and analyzed the moderating effect of user age, gender and usage experience variables. For a accuracy of predicted results, we focused on survey analysis with 641 real user samples. Compared to previous studies, it is meaningful that this research verified the conceptual difference between behavioral intention and usage behavior. As a result, all proposed hypotheses accepted and moderating effects are supported significantly in age and use experience moderating variables.