• Journal of Astronomy and Space Sciences
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• 제36권1호
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• pp.21-33
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• 2019

This paper focuses on the interpretation of radiation fluxes from active galactic nuclei. The advantage of positron annihilation spectroscopy over other methods of spectral diagnostics of active galactic nuclei (therefore AGN) is demonstrated. A relationship between regular and random components in both bolometric and spectral composition of fluxes of quanta and particles generated in AGN is found. We consider their diffuse component separately and also detect radiative feedback after the passage of high-velocity cosmic rays and hard quanta through gas-and-dust aggregates surrounding massive black holes in AGN. The motion of relativistic positrons and electrons in such complex systems produces secondary radiation throughout the whole investigated region of active galactic nuclei in form of cylinder with radius R= 400-1000 pc and height H=200-400 pc, thus causing their visible luminescence across all spectral bands. We obtain radiation and electron energy distribution functions depending on the spatial distribution of the investigated bulk of matter in AGN. Radiation luminescence of the non-central part of AGN is a response to the effects of particles and quanta falling from its center created by atoms, molecules and dust of its diffuse component. The cross-sections for the single-photon annihilation of positrons of different energies with atoms in these active galactic nuclei are determined. For the first time we use the data on the change in chemical composition due to spallation reactions induced by high-energy particles. We establish or define more accurately how the energies of the incident positron, emitted ${\gamma}-quantum$ and recoiling nucleus correlate with the atomic number and weight of the target nucleus. For light elements, we provide detailed tables of all indicated parameters. A new criterion is proposed, based on the use of the ratio of the fluxes of ${\gamma}-quanta$ formed in one- and two-photon annihilation of positrons in a diffuse medium. It is concluded that, as is the case in young supernova remnants, the two-photon annihilation tends to occur in solid-state grains as a result of active loss of kinetic energy of positrons due to ionisation down to thermal energy of free electrons. The single-photon annihilation of positrons manifests itself in the gas component of active galactic nuclei. Such annihilation occurs as interaction between positrons and K-shell electrons; hence, it is suitable for identification of the chemical state of substances comprising the gas component of the investigated media. Specific physical media producing high fluxes of positrons are discussed; it allowed a significant reduction in the number of reaction channels generating positrons. We estimate the brightness distribution in the ${\gamma}-ray$ spectra of the gas-and-dust media through which positron fluxes travel with the energy range similar to that recorded by the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) research module. Based on the results of our calculations, we analyse the reasons for such a high power of positrons to penetrate through gas-and-dust aggregates. The energy loss of positrons by ionisation is compared to the production of secondary positrons by high-energy cosmic rays in order to determine the depth of their penetration into gas-and-dust aggregations clustered in active galactic nuclei. The relationship between the energy of ${\gamma}-quanta$ emitted upon the single-photon annihilation and the energy of incident electrons is established. The obtained cross sections for positron interactions with bound electrons of the diffuse component of the non-central, peripheral AGN regions allowed us to obtain new spectroscopic characteristics of the atoms involved in single-photon annihilation.

• 한국양식학회지
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• 제21권4호
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• pp.203-212
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• 2008

참굴 유생의 최적 성장과 먹이생물의 이용성을 높이기 위해 현재 인공종묘생산에서 많이 이용되고 대량배양이 용이한 미세조류를 대상으로 그 요구조건을 구명하고, 나아가 인공배합사료개발에 요구되는 기초적인 사료 설계 자료를 얻기 위하여 대량 인공종묘생산 시 유생에 축적되는 영양소의 변화를 유생의 발달 단계에 따라 조사하였다. 유생의 일간 각장 성장은 $5.8{\sim}30.8\;{\mu}m$로 중형각정기 유생 이후 최대 성장률을 보였고, 사육 12일째 각장 $311.0\;{\mu}m$의 부착기 유생으로 성장하였다. 습중량, 건중량 및 AFDW는 각각 $0.5{\sim}15.0\;{\mu}g/larva$, $0.2{\sim}6.5\;{\mu}g/larva$ 및 $0.1{\sim}2.3{\mu}g/larva$이었다. 각각의 증중량은 D형 유생에서 각장 $100\;{\mu}m$까지는 감소하였고, 사육 8일째까지는 급격한 증가를 보였지만, 부착기 유생으로 발달하면서 감소하였다. 알의 일반성분 조성 중 회분은 7.7%로 전체 유생단계의 $30.3{\sim}39.6%$에 비해 매우 낮은 함량을 보였지만, 조단백질, 조지질 및 탄수화물의 함량은 전 유생단계에 비해 높았다. 유생의 조지질($0.6{\sim}1.1%$), 조단백($6.1{\sim}10.6%$), 탄수화물($1.0{\sim}2.7%$), 아미노산 및 지방산 함량은 포기각정기 유생까지는 감소하였고, 이후 어느 정도 축적되는 경향을 보였다. 알과 유생의 아미노산 조성 비율은 유생의 발달단계와 상관없이 비슷한 조성비로 glutamic acid (5.85%, $1.26{\sim}2.24%$)과 aspartic acid (4.67%, $0.97{\sim}1.70%$)가 가장 놀은 조성을 보였다. 전체 유생기 동안 필수아미노산으로서 leucine ($0.83{\sim}1.26%$), lysine ($0.90{\sim}1.35%$) 및 arginine ($0.92{\sim}1.25%$)이 성장함에 따라 비교적 높게 축적되었다. D형 유생에서 부착기 유생으로 발달하는 과정에서 조화지방산은 65.5% ($54.3{\rightarrow}17.1%$)로 줄어들었고, 단일불포화지방산과 고도불포화지방산은 각각 35.8% ($29.9{\rightarrow}40.6%$)와 484.6% ($7.8{\rightarrow}45.6%$)로 축적되었다. 이 중 palmitic acid ($9.9{\sim}37.0%$), oleic acid ($12.2{\sim}32.3%$) 및 linoleic acid ($2.0{\sim}33.6%$)가 비교적 높은 조성을 보였고, EPA와 DHA은 각각 $2.2{\sim}11.6%$, $2.0{\sim}4.5%$로 나타나, 전체 유생단계에서 EPA가 DHA에 비해 높은 조성비($1.1{\sim}3.5$, EPA/DHA)을 보였다.