• 한국안전학회지
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• 제27권5호
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• pp.9-15
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• 2012

The ignition characteristics in a confined axisymmetric coflow $CH_4$ jet were investigated numerically with the Fire Dynamics Simulator(FDS). The $CH_4$ fuel stream was diluted with main combustion product gases, such as $O_2$, $N_2$, CO, $CO_2$, and $H_2O$, and the mixed fuel stream was heated up to the sufficient temperature where a supplying fuel stream can be ignited. For the calculation of chemical reaction in the simulation, a 2-step global finite chemistry model was considered. Boundary condition for confined wall was optimized by investigating the effects of wall temperature on the ignition characteristics of fuel stream. In addition, the effects of composition of diluents in the fuel stream and fuel stream temperature on the ignition of fuel steam were investigated. The ignition characteristics of $CH_4$ stream with diluents were very sensitive to the wall temperature, composition of diluents in the fuel stream and fuel stream temperature.

• 한국대기환경학회지
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• 제28권2호
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• pp.190-202
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• 2012

Emissions of air pollutants and greenhouse gases (GHGs) by aircraft at the Gimhae International Airport (GIA) were investigated using the Emissions and Dispersion Modeling System (EDMS) version 5.1.3. The number of Landing and Take-Off (LTO) at the GIA for aircraft B737 was dominant, accounting for more than 60% of the total LTOs. For air pollutant emissions, CO was the most dominant pollutant by aircraft, followed by $NO_x$, VOCs, $SO_x$, etc. The emissions of CO, $NO_x$, and VOCs in 2009 (and 2010) at the GIA were 974 (968), 447 (433), 118 (122) ton/yr, respectively. The emissions of GHGs such as $CO_2$, $CH_4$, and $N_2O$ in 2009 (and 2010) were 110,795 (111,114), -0.157 (-0.151), and 1,989 (1,998) ton/yr, respectively. The negative number in $CH_4$ emission represents the consumption of atmospheric $CH_4$ in the engine. In addition, the emissions of most air pollutants (except for $PM_{10}$) and GHGs were estimated to be high in Taxi-Out and Climb-Out modes.

• 한국초지조사료학회지
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• 제20권1호
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• pp.7-12
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• 2000

오차드그래스의 종자배양에서 형성된 캘러스를 현탁배양하여 배양기간별 부정배 형성정도와 식물체 재분화율 등에 대한 몇 가지 실험을 수행하여 얻은 결과를 요약하면 다음과 같다. 종자유래의 캘러스를 현탁배양하였을 때, 세포 모양이 둥근것과 그들의 세포괴는 배양 50일 후에 최대치를 나타내었고 그 이후는 감소하였다. 현탁배양 기간에 따른 갤러스의 부정배 형성과 식물체 분화율은 배양 60일째 가장 높았으며, 그 이후는 감소하는 경향이었다. 현탁배양에서 배지 내에 첨가되는 casein hydrolysate (CH)의 적정농도는 $4\;g/{\ell}$인 것으로 나타났다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2013년도 제46회 KOSCO SYMPOSIUM 초록집
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• pp.45-46
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• 2013

Stabilization characteristics of highly $N_2$-diluted $CH_4-O_2$ flame in an axially two-section porous inert medium were experimentally investigated for its application to the waste gas scrubber in semiconductor manufacturing processes. The flame behaviors were observed with respect to the fuel and $N_2$ flow rates and the equivalence ratios. As a result, four kinds of flame behaviors such as stable, flashback crossing the interface, blowout and sudden extinction were observed. It was also found that there exists two flame regime divided by a critical fuel flow rate. In addition, the flame stability was discussed based on the $N_2$ index which means the abatement capacity of our combustor in scrubbing the waste gas from the semiconductor processes.

• 철학연구
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• 제145권
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• pp.195-215
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• 2018

플라톤은 "티마이오스"에서 자신의 우주론을 개진하면서, 우주제작자 제작의 본(本) 제작의 재료 제작의 장소 같은 핵심 개념들을 다루고 있다. 이 우주는 창조자인 데미우르고스가 영원히 존재하는 이데아를 본(本)으로 삼아, 무질서하고 혼란 가운데 있는 물질들에 도형과 수(數)의 원리에 따라 형태를 부여함으로써 제작된 것이다. 이 과정은 지성(nous)이 필연($anank{\bar{e}}$)을 설득하는 작업이며, 필연의 승복에 의해 양자는 결합하게 되어 우주를 탄생시키게 된다. 그런데 플라톤은 모든 생성물들을 자기 안에 받아들이는 '셋째 종류' 즉 '공간'($ch{\bar{o}}ra$)을 우주생성 이전부터 존재하는 것으로 상정한다. 이것은 '어렵고 분명치 않은 종류'로서 '가장 포착하기 힘든 것'이기 때문에, 이에 관한 논의는 '그럼직한 이야기'($eik{\bar{o}}s logos$)에 그칠 뿐이라고 한다. 따라서 플라톤은 다양한 비유 즉 '수용자', '유모', '어머니', '금', '새김바탕', '향유의 기초제', '공간', '자리' 등을 통해 공간의 성격을 구명하려고 한다. 아리스토텔레스부터 현대의 학자들에 이르기까지 플라톤의 공간($ch{\bar{o}}ra$)에 관한 무수한 해석이 나왔는데, 대체로 세 가지 유형으로 정리할 수 있다. 첫째, 플라톤의 '공간'($ch{\bar{o}}ra$)은 '빈 공간이다.', 둘째, 그의 공간은 아리스토텔레스의 '제1질료'와 유사하다, 셋째, '공간'과 '질료'의 양 측면을 모두 가진다. 만일 '코라'가 '빈 공간' 내지 '허공'(kenon)이라면 결국 무한한 공간이 될 것이다. 이것은 플라톤의 하나뿐인 유한한 우주와 상치된다. 그리고 '코라'는 생성물을 수용하는 것뿐만 아니라 생성에 영양과 힘을 제공한다. 다른 한편, '코라'는 '제1질료'와 유사하지도 않다. '코라'가 데미우르고스의 우주제작 이전에 존재 생성(제작 이전)과 함께 이미 있었으므로, '코라' 자체는 제작의 대상이 아니다. 반면 '제1질료'는 4원소의 구성요소로서 기체(基體)이다. 모든 생성물들을 자기 안에 담고 있는 '자리'로서의 공간성과 '어머니'처럼 생성물들에 영양과 힘을 제공하는 질료성이 공존한다는 해석이다. 플라톤은 여기서 논리적 일관성을 결여하게 된다. 그 이유는 우주의 시작에서 한 축이 되는 '공간'을 논의할 때, '그럼직한 이야기'의 한계를 벗어날 수 없기 때문이다. 플라톤 자신이 명료하게 밝혀내지 못한 '공간' 개념을 무리하게 해명하려는 시도는 또 다른 우(愚)를 범하게 될 것이다.

• 약학회지
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• 제38권4호
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• pp.455-461
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• 1994

Each nitrogen and oxygen site isotope enriched the cyclophosphamide metabolite phosphoramide mustard was synthesized. Reaction of N,N-bis(2-chloroethyl)phosphoramidic dichloride$[Cl_2P(O)N(CH_2CH_2Cl)_2]$ with benzyl alcohol and ammonia gave N,N-bis(2-chloroethyl)phosphorodiamidic acid phenylmethyl ester $[BzO(H_2N)P(O)N(CH_2CH_2Cl)_2]$. Catalytic hydrogenation of this benzyl ester followed by the addition of cyclohexylamine provided PM. Incorporation of $^{15}NH_3$ into this general scheme gave PM with a $^{15}NH_2$ moiety. Glycine-$^{15}N$ was converted to bis(2-chloroethyl)amine-$^{15}N$ hydrochloride which, in turn, provided for N,N-bis(2-chloroethyl)phosphorodiamidic-$^{15}N$ dichloride. Use of this compound in the general synthetic pathway yielded PM CHA with $^{15}N$ in the mustard moiety. $^{17}O$-Enriched PM was generated through the use of benzyl alcohol-$^{17}O$. To obtain the alcohol, labelled benzaldehyde was made by exchange with $^{17}OH_2$ and was then reduced with sodium borohydride.

• Toxicological Research
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• 제18권4호
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• pp.363-367
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• 2002

Reactive of gen species (ROS) contribute to several cellular function and are involved in the regulation of signal transduction, gene expression, and proliferation. In the present study, we investigated the effect of $H_2O_2$ treatment on IgM secretion in LPS-stimulated murine B Iymphoma, CH12.LX. Cells were treated directly With $H_2O_2$ and stimulated with LPS. $H_2O_2$ treatment during 72 h time period inhibited IgM secretion in LPS-stimulated CH12.LX cells in a dose- and time-dependent manners. After treatment with 50 $\mu\textrm{M}$ $H_2O_2$ during 72 h time period, the level of IgM in LPS-stimulated CH12.LX cells was markedly decreased, whereas cell viability was not significantly changed. Addition of $H_2O_2$ concomitantly with LPS, or 12 h post-LPS stimulation, produced a significant inhibition of IgM secretion, Whereas inhibitory effect of $H_2O_2$ on IgM secretion was not observed when added 24 h after LPS stimulation. These findings suggest that $H_2O_2$ can inhibit the secretion of IgM in LPS-stimulated CH15.LX cells, and may alter the events necessary for terminal B cell differentiation.

• 한국포장학회지
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• 제27권1호
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• pp.35-40
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• 2021

Calcium hydroxide (CH) reacts with CO2 to produce moisture, and sodium carbonate (SC) reacts with CO2 in the presence of moisture. Using these different characteristics of these two reactants, a CH/SC mixture of CO2 absorber tuned for kimchi ripening to produce CO2 in a flexible package was selected. A ratio of CH:SC (1:2) in highly gas permeable microporous spunbonded film (Tyvek) sachet was found to be appropriate for delayed and consistent CO2 absorption useful for kimchi package. Addition of superabsorbent polymer (SAP) as moisture buffer was helpful for boosting the consistency of CO2 absorption. In a package of 0.5 kg kimchi at 10℃, the sachet consisting of 0.794 g of CH + 2.276 g of SC + 0.4 g of SAP suppressed its volume expansion and maintained a suitable range of CO2 partial pressure (PCO2) steadily inside. These optimal conditions may vary depending on the type and salinity of kimchi, storage and distribution temperature, and the material and area of the absorber sachet. This study showed a potential of mixture CO2 absorber to be tuned for CO2 producing packaged kimchi for the purpose of keeping consistent PCO2 at tolerable volume expansion.

• Bulletin of the Korean Chemical Society
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• 제20권7호
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• pp.805-808
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• 1999

Second-order-rate constants (kN) have been measured spectrophotometrically for the reactions of 4-nitrophenyl 2-furoate (1) with a series of secondary alicyclic amines in H2O containing 20 mole % DMSO at 25.0℃. 1 is about 5-8 times more reactive than 4-nitrophenyl benzoate (2), although 1 is expected to be less reactive than 2 based on MO calculations and 13 C NMR study. The Brфnsted-type plots for the aminolysis reactions of 1 and 2 are linear with βnuc values of 0.78 and 0.85, respectively. The replacement of the CH=CH group by an O atom in the acyl moiety (2->1) does not cause any mechanism change. The reaction of piperidine with a series of substituted phenyl 2-furoates gives a linear Hammett plot with a large ρ- value (ρ- = 2.88) when σ- constants are used. The linear Brфnsted and Hammett plots with a large ρ- value suggest that the aminolysis reaction of 1 proceeds via rate-determining break-down of the addition intermediate to the porducts.

• Asian-Australasian Journal of Animal Sciences
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• 제13권5호
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• pp.600-604
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• 2000

Exp. I, the study was conducted to examine the supplementation levels of cassava hay (CH) in dairy cows. Six multiparous Holstein-Friesian crossbreds were paired and randomly assigned in a change-over design to receive three levels of CH supplement at 0, 0.8 and 1.7 kg DM/hd/d. Concentrate was supplemented at the same level (1:2; concentrate:milk yield) while urea-treated (5%) rice straw was offered on ad libitum basis. The results revealed that supplementation of CH could significantly reduce concentrate use resulting in similar milk yield (12.5, 12.12 and 12.6 kg/hd/d) and significantly enhanced 3.5% FCM (14.21, 15.70, 14.9 kg/d, respectively). Moreover, CH supplementation significantly increased milk fat and milk protein percentages especially at 1.70 kg/hd/d. Concentrate use could be significantly reduced by 27% at 1.7 kg/hd/d CH supplementation. Exp. II, supplementation of cassava hay to replace concentrate use was studied in lactating-Holstein Friesian crossbreds grazed on Ruzi grass. Six multiparous cows in mid-lactating periods were paired and randomly assiged according to a change-over-design to receive three dietary treatments, $T_1=0kg$ cassava hay (CH) in 1:2 concentrate supplementation (CS) to milk yield (MY), $T_2=1.0kg$ DM CH/hd/d in 1:3 CS to MY, $T_3=1.7kg$ DM CH/hd/d in 1:4 CS to MY, respectively. The results were found that milk yield were similar among treatments while protein, lactose and solids-not-fat percentages were highest (p<0.05) in cows receiving CH at 1.0 kgjhd/d. Most significant improvement from CH supplementation was the ability to reduce concentrate use by 42% which could provide a higher income for small-holder dairy farmers. In addition, milk thiocyanate was enhanced from 5.3 to 17.8 ppm (p<0.05) in the control and in the CH supplemented group (1.7 kg/hd/d), respectively. Moreover, CH supplementation could significantly reduce concentrate level for diary feeding thus resulted in more economical return. Cassava hay demonstrated as a potential and high-quality on-farm feed resource especially for dry season feeding in the tropics.