구형 전파 화염 방법을 사용한 SNG 연료의 층류연소속도 측정에 관한 연구

조서희(Seo Hee Cho),이기만(Kee Man Lee),송준호(Jun Ho Song),박기철(Ki Cheol Park) 한국연소학회 2019 KOSCOSYMPOSIUM논문집 Vol.2019 No.5

대향류 화염에서 FGR이 적용된 저공해 연소의 수치적 해석: Part I. 저 NOx 연소특성

조서희(Seo-Hee Cho),이기만(Kee-Man Lee) 한국가스학회 2019 한국가스학회지 Vol.23 No.6

저공해 연소를 위한 방법 중 하나인 배기가스 재순환(flue gas recirculation, 이하 FGR)은 질소산화물 저감에 효과적인 연소 기법이다. 이를 메탄/공기 대향류 예혼합화염에 적용하여 화염의 특성변화와 NOx 생성 기구를 파악하기 위한 수치해석을 진행하였다. 신장률에 따라 배출되는 생성물들의 몰분율이 달라진다는 점을 고려하여 재순환율은 생성물을 기준으로 정의되었으며, 실제 연소 시스템을 반영하기 위해 주요 생성물인 CO₂, H₂O, O₂ 그리고 N₂를 희석제로써 재순환하였다. FGR 기법이 적용됨에 따라 특정한 신장률 조건에서 최대화염 온도의 전환점이 발견되었다. 또한, 재순환율이 증가함에 따라 온도와 NO의 경향이 달리 나타났으며, 이를 파악하고자 NO 반응을 열적 NO와 Fenimore NO로 구분하여 분석하였다. One of the methods for low-pollution combustion, flue gas recirculation(FGR) is effective to reduce nitrogen oxides and it was applied in CH₄/air premixed counterflow flames to identify the change of flame characteristics and NOx mechanisms. Considering that the mole fraction of the products varied depending on the strain rates, the major products: CO₂, H₂O, O₂ and N₂ were recirculated as a diluent to reflect the actual combustion system. With the application of the FGR technique, a turning point of maximum flame temperature under certain strain rate condition was found. Furthermore as the recirculation ratio increased, the tendency of NO was changed before and after the turning point and the analysis on thermal NO and Fenimore NO production was conducted.

구형전파 화염에서 SNG 연료 조성변화에 대한 층류 연소속도 측정

조서희(Seo Hee Cho),이기만(Kee Man Lee) 대한기계학회 2022 大韓機械學會論文集B Vol.46 No.3

합성천연가스(SNG: synthetic natural gas)의 수소 함량에 따라 연료 조성비를 달리하여 NTP 조건의 구형전파 화염의 연소특성과 층류 연소속도를 실험적으로 측정하였다. SNG는 LNG와의 호환성을 위하여 WI(Wobbe index)=52 MJ/m3로 고정하여 연료의 발열량을 맞추었으며, WI를 contour plotting을 통해 가시적으로 확인하였다. 또한, 수치해석을 병행해 네 가지 화학 반응 메커니즘 중 오차율이 가장 낮은 ARAMCO 2.0을 선정하였으며 도출된 계산 결과를 실험 결과와 비교하였다. 당량비 0.7~1.3에서의 SNG내 수소함량이 3%인 경우에는 ARAMCO 2.0과 상당히 일치하였으나, 수소 함량이 19%까지 증가함에 따라 과농한 연소조건에서 오차율이 10% 이상 발생하였다. 이러한 차이는 추후 민감도 분석을 통해 과농조건에서의 연소속도를 개선하여 아직까지 개발되지 않은 SNG 연료에 최적화된 수정된 반응 메커니즘을 제안하고자 한다. The combustion characteristics and laminar burning velocity of outwardly propagating spherical flames were measured by varying the fuel composition ratio with the hydrogen content of synthetic natural gas (SNG) under NTP condition. For compatibility with LNG, the Wobbe index of SNG was fixed at 52 MJ/m³, and it was visually confirmed through contour plotting. In addition, ARAMCO 2.0 mechanism with the lowest error rate was selected among the four chemical reaction mechanisms, and its numerical results were compared with the experimental results. When the hydrogen content in SNG was 3%, it was consistent with ARAMCO 2.0 at the equivalent ratio of 0.7 to 1.3, but as the hydrogen content increased to 19%, the error rates occurred over 10% under rich conditions. To improve these differences, sensitivity analysis would be performed, particularly at the rich conditions, and a modified ARAMCO 2.0 mechanism optimized for SNG, which has not been developed, would be proposed.

정적 연소기에서 합성천연가스(SNG) 연료의 폭발특성에 관한 실험적 연구

조서희(Seo Hee Cho),진은서(Eun Seo Jin),이기만(Kee Man Lee) 한국연소학회 2023 KOSCOSYMPOSIUM논문집 Vol.2023 No.5

이중 주어 구문 새로 보기 - 기본문형 설정과 관련하여

목정수(Mok, Jung-soo),조서희(Cho, Seo-hee) 국어국문학회 2021 국어국문학 Vol.- No.196

본고는 우선 ‘가’와 ‘는’과 같은 한정조사류와 명사(구)의 결합이 형태론적 구성이 아니라 담화 · 화용론과 유기적인 관계 하에서 펼쳐지는 통사 현상, 즉 통사적 구성을 이룬다는 것을 기욤(Guillaume)의 정신역학 모델을 원용하여 주장한다. 이어서 문장의 기본문형을 설정할 때, 한정조사에 의한 정보구조가 기본문형 표상에 적절히 반영되어야 함을 제안한다. 그 과정에서 기존에 한국어의 특수한 현상으로 치부됐던 이른바 ‘이중 주어 구문’은, 다른 더 기본이 되는 심층구조로부터 도출된 것이 아닌, 그리고 서술절을 안은 복문으로 분석되는 것이 아닌, 그 자체로 [NP1(은) NP2(가) V-어미]라는 형식의 단문임이 밝혀진다. 다만, 그간 이중 주어 구문으로 분류되어 온 여러 유형 가운데 ‘코끼리는 코가 길다’류와 ‘나는 호랑이가 무섭다’류만이 기본문형에 포함되어야 한다는 것이 우리의 주요 주장인데, 그 근거를 여러 유형의 이중 주어구문의 통사 · 의미적인 비교 분석을 통하여 제시한다. 따라서 기본문형을 이루는 이중 주어 구문의 서술어는 한 자리 서술어 용법 이외에, ‘소유주’ 또는 ‘경험주’라는 의미역의 주어 논항 NP1과, ‘대상’이라는 의미역의 비주어 논항(=‘가형 목적어’) NP2를 추가로 요구하는 두 자리 서술어의 용법을 갖는다는 것이 드러난다. 그 밖의 다른 유형의 이중 주어 구문들은 표면 구조가 [NP1(은) NP2(가) V-어미]로 같더라도 기본문형에 포함되지 않는다. 예를 들어, ‘커피는 잠이 안 온다’류는 ‘커피를 마시면(나) 잠이 안 온다’ 구성 정도로 해석된다는 점에서 부가어 성분의 주제화를 통해 도출된 유표적인 문장으로 분석되고, ‘철수는 마누라가 회사를 다닌다’류는 주로 ‘철수는 마누라가 회사를 다녀서 돈 걱정을 안 한다’라는 복문 구성 중의 일부 구조로 분석된다. In this article, we demonstrate in the framework of psychomechanics of language founded by Guillaume that the combination of NP and particles such as ‘ga’, ‘neun’ is not a morphological construction but constitutes a syntactic construction. And we claim that the form of basic sentence pattern should reflect information structure or discourse structure so that it can be consistent with the theory of markedness. So the patterns [X-(neun) Y-(ga) V-ending] and [X-(neun) Y-(leul) V-ending] replace the traditionally established patterns [X-ga Y-ga V] and [X-ga Y-leul V], respectively. The basic pattern [X-(neun) Y-(ga) V-ending] is, in itself, analysed as a simple sentence, even though it was regarded as complex sentence embedding ‘sentential predicate’ in school grammar. Among different types of ‘double subject constructions’, only two types like ‘코끼리는 코가 길다(Elephants have a long nose)’ and ‘나는 호랑이가 무섭다(I am scared of tigers)’ should be classified as basic sentenc patterns. In these constructions, the predicates ‘길-’ and ‘무섭-’ have the usages of two-place predicate. Therefore, their argument structures or semantic structure can be represented as follows; 〈X have_long Y〉 and 〈X be scared of Y〉. The other so-called double subject constructions such as ‘커피는 잠이 안 온다(With coffee, I can’t sleep’ or ‘철수는 마누라가 회사를 다닌다(As for Paul, his wife works in a company)’ are excluded from the category of basic sentence patterns, which are derived by topicalization from the marked construction ‘커피를 마시면/커피로는 (나) 잠이 안 온다(If I drink coffee/with coffee, I can’t sleep)’ or can be described as a part of the complex sentence as underlined in ‘철수는 마누라가 회사에 다녀서 돈 걱정을 안 한다(Paul does not have any financial concern, because his wife works in a company)’.

정적연소기에서 암모니아 크래킹 모사 연료의 폭발 특성

김인호(Inho Kim),조서희(Seo Hee Cho),이기만(Keeman. Lee) 한국연소학회 2023 KOSCOSYMPOSIUM논문집 Vol.2023 No.11

한국 담수어류 두 근연종 한둑중개(Cottus hangiongensis)와 둑중개(Cottus koreanus)의 초기생활사 차이에 따른 개체군 유전적 구조 특성

백송이 ( Song Yi Baek ),강지현 ( Ji Hyoun Kang ),조서희 ( Seo Hee Cho ),장지은 ( Ji Eun Jang ),왕주현 ( Ju-hyoun Wang ),이황구 ( Hwang-goo Lee ),최준길 ( Jun-kil Choi ),이혁제 ( Hyuk Je Lee ) 한국환경생태학회 2016 한국환경생태학회 학술대회지 Vol.2016 No.2

Levels of genetic diversity and spatial genetic structure among freshwater fish populations are influenced by life history traits of the species including life history styles (e.g., fluvial, amphidromous). However, whether and how divergent life history styles contribute to shaping population genetic structure of freshwater fish species remain rarely tested comparatively for closely related species. A species pair of freshwater sculpins, Cottus hangiongensis- C. koreanus, which both occur in the Korean Peninsula, shows considerable variation in distribution, life history style and conservation status. Cottus hangiongensis is widely distributed across the eastern Korean Peninsula, northern Japan and Russia, whereas C. koreanus is restricted to the Korean Peninsula. The former species has been protected by the Korean government as a ‘legally protected species II’ since 2012, but the latter was recently released from the red list of endangered species. Although these two species are a sister taxon with morphologically virtually indistinguishable, they differ in life history styles, type of larvae and habitat selection: C. hangiongensis shows “amphidromous” life history with pelagic larvae and occurs from mid-to-downstream of the river, whereas C. koreanus displays “fluvial” life history with benthic larvae and inhabits upstream of the river. In the present study, we examined and compared population genetic structure between two congeneric sister sculpin species from South Korea that show a notable divergence in life history styles using a combination of mitochondrial DNA (mtDNA) and microsatellite markers. Individuals of C. hangiongensis (N = 200) and C. koreanus (N = 274) were collected using skimming nets from 18 different locations in South Korea (C. hangiongensis: 5 locations - Samcheok, Yangyang, Okgye, Gangneung, Uljin; C. koreanus: 13 locations - Pyeongchang Heongjung-valley, Mitan Myeon, Jeongseon, Wonju Oakvalley, Gangnim Myeon, Mt. Chiaksan National Park from the South Han River; Goseong, Yanggu, Inje, Gapyong, Pocheon from the North Han River; Samcheok, Yangyang from the East flowing rivers). Based on mtDNA control region (465, 467 bp) and seven nuclear microsatellite loci, we found that the overall levels of within-population genetic diversity were substantially greater for C. hangiongensis (mean mtDNA haplotype richness: 2.128 ± 1.470; mean allelic richness: 14.029 ± 1.065) than for C. koreanus (mean mtDNA haplotype richness: 1.084 ± 1.794; mean allelic richness: 5.095 ± 2.861). These results indicate that an amphidromous species C. hangiongensis, which produces many small eggs from which pelagic larvae hatch then spend 1-2 months in the sea before migrating to river mouths, has greater within-population genetic diversity than a fluvial species C. koreanus, which lays a small number of large eggs from which benthic larvae develop directly. The inbreeding coefficient (FIS) values were generally low, ranging from -0.001 to 0.052 for C. hangiongensis and from -0.294 to 0.059 for C. koreanus, suggesting that rather random mating has been taking place in both species. The degree of genetic differentiation between populations at both mtDNA and microsatellite markers was much greater for the ‘fluvial’ species, C. koreanus with direct-developing benthic larvae than for the ‘amphidromous’ species, C. hangiongensis with pelagic larvae. These findings suggest that all the populations of C. koreanus investigated are genetically strongly isolated and thus divergent one another, most likely due to lack of gene flow among populations because of their limited migratory range by physical isolation and/or behavioral constraint. By comparison, C. hangiongensis showed lack of spatial genetic structure, which is probably due to high on-going gene flow during the free-swimming larval stage of this fish. The Mantel tests of both C. hangiongensis and C. koreanus showed significant correlation between genetic (FST) and geographic distances (km) across all the populations, based on neither mtDNA nor microsatellites. STRUCTURE and factorial correspondence analysis (FCA) of seven microsatellite genotypes detected a single genetic make-up with in C. hangiongensis, but almost each of the local populations comprising its own unique genetic integrity within C. koreanus. These results corroborate the hypothesis that life history divergence strongly affects the spatial population genetic structure of these two species. The greater spatial genetic structure observed for C. koreanus than for C. hangiongensis may have resulted from much lower levels of gene flow, most likely due to its poorer dispersal capacity (and physical isolation among populations) because it lacks the free-swimming larval phase that the latter species has. Overall, we conclude that alternative life histories (fluvial vs. amphidromous) have resulted in strikingly different patterns of population genetic structure between these sister species of freshwater sculpins in South Korea. The observed patterns highlight how divergent life history evolution may influence broader trends of population connectivity in freshwater fish, with significant implications for management and conservation particularly for these endangered fishes. This study sheds intriguing insights into the effects of divergent life history styles on the genetic diversity and genetic structure of South Korean populations of a sister species pair C. hangiongensis-C. koreanus, which will contribute to a better understanding of how these two species have diverged ecologically and speciated in general.