Hydrogen cyanide (HCN) and hydrogen isocyanide (HNC) are isomers with similar chemical properties. However, HNC can be converted into other molecules by reactions with atomic hydrogen (H) and atomic oxygen (O), resulting in a variation of the HCN/HNC abundance ratio. These reaction rates are sensitive to gas temperature, resulting in different abundance ratios in different temperature environments. The emission of HCN and HNC was found to distribute along ring structures in the protoplanetary disk of V883 Ori. HCN exhibits a multi-ring structure consisting of inner and outer rings. The outer ring represents a genuine chemical structure, whereas the inner ring appears to display such characteristics due to the high dust continuum optical depth at the center. However, HNC is entirely depleted in the warmer inner ring, while its line intensity is similar to that of HCN in the colder outer ring. In this study, we present a chemical calculation that reproduces the observed HCN/HNC abundance ratio in the inner and outer rings. This calculation suggests that the distinct emission distribution between HCN and HNC results from a currently ongoing outburst in V883 Ori. The sublimation of HCN and HNC from grain surfaces and the conversion of HNC to HCN determine their chemical distribution in the heated, warm inner disk.

본 연구에서는 황소자리 분자운에 위치한 L1521F-IRS의 운동학적 특성을 알아보기 위하여 HCN(J=1-0) 분자선 을 이용한 전파관측을 수행하여 분석하였다. 약한 밝기의 천체에 대한 높은 공간 분해능 지도 관측을 위하여 미국 Tucson에 위치한 Arizona Radio Observatory 12 m 망원경을 이용하였으며, 대상의 주변을 충분히 포함할 수 있도록 5지점×5지점 광역관측모드로 관측대상의 중심을 포함한 3.7'×3.7' 영역을 관측하였다. HCN 분자선 적분 밝기 분포자료는 분자운핵 L1521F가 고밀도 환경에서 분자의 심각한 결핍 현상이 없이 중심에서 강한 밝기를 보여 주고 있음을 보았다. L1521F에서 발견된 적외선원의 위치를 기준으로 동쪽방향에는 청색비대칭 분광선이 서쪽에는 적색비대칭 분광선이 존재하고 이들의 분포가 기존의 적외선영상에서 나타난 고깔모양과 잘 일치하는 모습을 보이고 있는 것으로 보아 L1521F-IRS에서 나오는 가스 쌍극류의 존재를 확인 할 수 있었다.

We present mm observations with the IRAM 30m radiotelescope of the HCN (J=1-0) and HCO+ (J=1-0) emission lines from Giant Moleculat Clouds (GMC) in the disk of the Andromeda Galaxy, The selected GMC targets have various morphology and environments, including locations within spiral arms or in interarm regions and with galactocentric radii ranging from 2.4 to 15.5 kpc over the disk. The radial distributions of the ratios HCN/CO and HCO+ /CO are discussed and their values are compared to other galaxies.

We present a progress report on HCN(1-0) line observations toward starless cores to probe inward motions. We have made a single pointing survey toward the central regions of 85 starless cores and performed mapping observations of 6 infall candidate starless cores. The distributions of the velocity difference between HCN(1-0) hyperfine lines and the optically thin tracer N2H+(1-0) are significantly skewed to the blue, meaning that HCN(1-0) frequently detects inward motions. Their skewness to the blue is even greater than that of CS(2-1) Lee et al., possibly implying more infall occurrence than CS(1-0). We identify 19 infall candidates by using several characteristics illustrating spectral infall asymmetry seen in HCN(1-0) hyperfine lines, CS(3-2), CS(2-1), DCO+(2-1) and N2H+ observations. The HCN(1-0) F(O-l) with the least optical depth usually shows a similar intensity distribution to that of N2H+ which closely traces the density distribution of the cores, indicating that HCN(1-0) is less chemically affected and so believed to reflect kinematics occurring in rather inner regions of the cores. Detailed radiative transfer model fits of the spectra are underway to analyze central infall kinematics in starless cores.

Observations of the J=1-0 transition line of HCN were made at the center of Comet C/1995 O1 (Hale-Bopp) from November, 1996 to April, 1997 with the 14-m radio telescope at the TRAO (Taeduk Radio Astronomical Observatory). From the obtained data, an HCN production rate at each observed date was derived. The rapid variation of the HCN production rate near the perihelion was detected, and it is thought to be caused by jet(s) from the nucleus. The correlation between the visual magnitude and the HCN production rate is found to be QHCN=27.03−0.11(mv−5logΔ) QHCN=27.03−0.11(mv−5logΔ) .

To develope a microbial weed control agent, HCN-producing bacteria were isolated, and their characteristics were investigated. A selected strain of WA15 was identified as Pseudomonas koreensis by morphological, cultural, biochemical and 16S rRNA gene analyses. The conditions for HCN production was investigated by a One-Variable-at-a-Time (OVT) method. The optimal HCN production conditions were tryptone 1%, glycine 0.06%, NaCl 1% , and an initial pH and temperature of 5.0 and 30℃, respectively. The major component for HCN production was glycine. Under optimal conditions, HCN production was about 3 times higher than that of the basal medium. The WA15 strain had physiological activities, such as indoleacetic acid that was associated with the elongation of plant roots and siderophore and ammonification inhibiting fungal growth, and produced hydrolytic enzymes, such as cellulase, pectinase and lipase. The strain was able to inhibit the growth of phytopathogenic fungi, such as Rhizoctonia solani, Botrytis cinerea and Fusarium oxysporum, by the synergistic action of volatile HCN and diffusible antimicrobial compounds. A microscopic observation of R. solani that was teated with the WA15 strain showed morphological abnormalities of fungal mycelia, which could explain the role of the antimicrobial metabolites that were produced by the WA15 strain. The volatile HCN produced by the WA15 strain was also found to have insecticidal activity against termites. Our results indicate that Pseudomonas koreensis WA15 can be applied as a microbial agent for weed control and also as a termite repellent. Furthermore, it could be applied as a microbial termiticidal agent to replace synthetic insecticides.

폐기물을 이용한 가스화 공정은 이론적으로 요구되는 산화제의 양보다 적은 양의 공기를 이용하여 환원분위기에서 흡열반응에 의해 합성가스를 생산하며 이와 동시에 폐기물의 열적처리 개념도 포함된다. 가스화 공정에서 발생되는 각종 오염물질은 후단 공정에 구성된 정제설비에 의해 제거되며 고품질 합성가스의 생산을 위해 가스화 반응기 후단의 정제설비는 벤츄리스크러버, 중화세정탑, 탈황세정탑, 습식전기집진기, 활성탄흡착탑으로 구성되었다. 전체 정제설비의 총괄효율을 분석하기 위해 시료 가스는 가스화 반응기 후단과 활성탄흡착탑 후단에서 채취되어 분석되었으며 시료 채취방법은 대기오염공정시험방법을 참조하였다. 본 연구에서는 환원성 가스상 오염물질 중에서도 맹독성 물질인 HCN과 악취물질인 NH₃에 대한 정제설비에서의 제거 효율을 분석하였으며 대기배출허용기준 초과 여부를 판단하였다. HCN의 대기배출허용기준은 모든 시설에서 10 ppm 이하이며 본 실험에서의 제거 효율은 99%, 배출농도는 2.5 ppm으로 나타났다. NH₃의 대기배출허용기준은 30 톤/일급 설비를 기준으로 30(12) ppm이며 실험결과에서 제거효율은 95%, 배출농도는 8.90(12) ppm으로 분석되어 Pilot 설비에 구성된 정제설비는 HCN과 NH₃의 제거에 적합한 것으로 나타났다.

인간 배아줄기세포는 모든 종류의 세포로 분화할 수 있는 전분화능을 가지고 있어, 이를 이용한 심근세포로의 분화 및 기능 분석에 대한 연구가 활발히 진행되고 있다. 분화된 심근세포는 심근세포 특이적 유전자의 발현 및 기능성 등의 특성을 나타내는 것으로 알려져 있다. 본 연구에서는 심장의 자발적 박동 (autonomic rhythm)을 설명하는 전기생리학적 기전들 중 하나인 과분극-활성 양이온통로 (hyperpolarization and cyclic nucleotide-activated (HCN) family)의 발현 여부를 분석하였다. 미분화 인간 배아줄기세포에 10 ng/㎖ BMP2를 4일 동안 처리하여 심근전구세포로의 직접 분화를 유도하였다. 분화유도 18일 후, 세포를 PBS로 세정한 뒤, trizol을 이용하여 RNA를 추출하였다. 1 ug의 RNA를 이용하여 cDNA를 합성한 후, 칼슘채널 특이 유전자의 발현을 RT-PCR 방법을 이용하여 측정하였다. 또한, 칼슘 특이적 시약인 fluo-4를 염색하여 자발적 수축현상과 연관되어 세포내 칼슘농도변화가 동반되는지 확인하였다. 직접분화법을 이용하여 분화된 인간 배아줄기세포 유래 심근세포는 분화유도 14일 후에 박동을 나타내었으며, 칼슘채널 특이적 유전자 hyperpolarization and cyclic nucleotide-activated(HCN) family에 속하는 HCN-1, -2, -4 등을 발현하였다. 또한, 이처럼 분화된 심근세포에서 fluo-4 형광의 주기적 증감이 나타나는 것을 확인하였다. 이러한 현상들 자발적 박동 시작 후 4일째에 최고치를 보였다. 본 연구에서는 인간 배아줄기세포 유래 심근세포에서 pacemaker channel의 역할을 하는 HCN family의 존재 및 관련 유전자의 발현을 확인함으로써, 인간 배아줄기세포 유래 심근전구세포의 기능성을 제시하는 바이다.

In aqueous acid solution [Cr(CN)_6]^3- aquates via a series of stepwise stereospecific reactions to give [Cr(H_2O)_6]^3+ as the final product.Some of the intermediate cyanoaquo complexes in the sequence have been isolated.These complexes aquate by both acid independent and acid denpendent pathways,the latter involving protonation of the cyano ligands followed by aquation of the singly protonated species. The kinetic data for the aquation of [CrCN(H_2O)_5]^2+ are consistent with the transition state structure, [(H_2O)_4Cr(CN)-OH-Cr(H_2O)_5]^3+.Addition of Cr^2+ to solutions of cyanocobalt(III) complexes produces the metastable intermediate[CrNC(H_2O]^2)+.This isomerizes to in a Cr^2+ -catalyzed reaction which occurs by a ligand-bridged electron-change mechnism. From acid catalysis on these aquation reactions, it product HCN. Especially, HSO_3 ions do the role of catalyst in the formation of HCN from CrCN^3+.