• Journal of Ecology and Environment
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• 제32권2호
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• pp.109-113
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• 2009

Tree-ring width analysis has been used to assess the effects of air pollution on tree growth around industrial complexes. Our study was conducted to elucidate the effect of air pollutants on annual ring growth in black pines (Pinus thunbergii) of age 41$\sim$48 years around Ulsan Metropolitan City. The growth data were analyzed by multiple regression and the results are as follows: 1. The annual ring increment of black pines increased with tree age until age 40 years and then decreased gradually after age 40 years. 2. The increment of annual ring width of black pines was affected more by precipitation and evapotranspiration than air temperature. An annual ring decline appeared in the years 1968$\sim$1983, when annual ring indices below zero were observed. Decreased annual ring growth during this period may have been due to air pollution. 3. The heavy metal with the strongest effect on annual ring growth of black pines in the experimental stand was lead (Pb). The concentration of lead in the stand was estimated as over 6 ppm. 4. The technique of tree-ring width analysis may be useful for estimation of the extent of pollution in forest areas near industrial complexes.

• 충청수학회지
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• 제17권2호
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• pp.191-196
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• 2004

• 대한수학회보
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• 제38권1호
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• pp.149-156
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• 2001

In this paper, we initiate the investigation of ring in which all the additive endomorphisms are generated by ring endomorphisms (AGE-rings). This study was motivated by the work on the Sullivan’s Research Problem [11]: Characterize those rings in which every additive endomorphism is a ring endomorphism (AE-rings). The purpose of this paper is to obtain a certain characterization of AGE-rings, and investigate some relations between AGE and LSD-generated rings.

• 수산해양기술연구
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• 제51권4호
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• pp.592-599
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• 2015

본 연구는 2014년 1월부터 12월까지 강원도 영진 연안에서 패류형망에 의해 채집된 접시조개의 패각을 이용하여 연령과 성장특성을 조사하였다. 접시조개의 윤문형성시기는 9-10월에 연 1회 형성되는 것으로 추정된다. 이론적 최대각장($SL_{\infty}$)은 236.3 mm, 성장계수(k)는 0.061/year의 값을 얻을 수 있었다. 또한 각장이 0일 때의 이론적 연령 t0 는 -0.184 year로 추정되었다. 따라서 접시조개의 각장과 연령과의 성장식은 $SL_t=236.3(1-e^{-0.061(t+0.184)})$ 으로 나타났다.

• Journal of Ginseng Research
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• 제20권1호
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• pp.72-77
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• 1996

This study was conducted to establish an identification method age for cultivated ginseng (Panax ginseng C.A. Meyer) based on counting the stem vestige at rhizome. Weight, diameters of body and lateral roots, and ratios of those diameters were overlapped with those of other ages, so these are not enough as a criterion for identification of ginseng age. Since the stem vestige at rhizome was remained clearly from the 3rd-year age, root age can be the number of stem vestige +2. The number of stem vestige should be counted at the one side of rhizome with abundant vestige for multi stewed plant. It is necessary that the number of year-ring in root is investigated for rhizome damaged plant, but it must be considered that the new year-ring can be shown clearly after around loth of June. All dormant roots had damaged rhizome by some reasons.

• The Korean Journal of Ecology
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• 제21권3호
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• pp.251-255
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• 1998

To elucidate the effects of a hydroelectric dam construction on annual ring growth of Pinus densiflora, the annual ring widths of 68 trees collected from 7 sites were closely examined. The result was analyzed to ask three special questions first, whether there are real effects of dam construction on the radial growth second, would the magnitude of the effect be different due to two periods of under-construction and post-construction the last, would it be different among age classes. Annual ring growth has been significantly enhanced by the dam construction. Specially, its effect was marked after the construction was finished and the reservoir was filled up with water. There was, however, no remarkable evidence that pine growth would be reduced while the dam was under construction, even though there was a minor decreasing trend. The magnitude of the effect was different among age groups. That is, the changed condition after the construction enhanced relatively the growth of aged trees monre. According to other meterological research since the dam was constructed, the reasons of enhancing pine growth assumed to be the increase of daily temperature, the decreased of daily temperature difference and the increased of rainy days.

• 천문학회보
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• 제38권1호
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• pp.31.2-31.2
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• 2013

We use grid-based hydrodynamic simulations to study star formation in nuclear rings in barred galaxies. The gaseous medium is assumed to be infinitesimally thin, isothermal, and unmagnetized. To investigate various situations, we vary the total gas content in the bar regions and the bar growth time. We find that star formation rate (SFR) in a nuclear ring is determined by the mass inflow rate to the ring rather than the total gas mass in the ring. The SFR shows a strong primary burst and weak secondary bursts at early time, and declines to small values at late time. The primary burst is caused by the rapid gas infall to the ring due to the bar growth, with its duration and peak depending on the bar growth time. The secondary bursts result from re-infall of the ejected gas by star formation feedback of the primary burst. When the SFR is low, ages of young star clusters exhibit an azimuthal gradient along the ring since star formation takes place mostly near the contact points between the dust lanes and the nuclear ring. When the SFR is large, on the other hand, star formation is widely distributed throughout the whole length of the ring, with no apparent age gradient of star clusters. Regardless of SFR, star clusters have a positive radial age gradient, with younger clusters located closer to the ring, since the ring shrinks in size over time.

• 한국해양학회지
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• 제8권2호
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• pp.68-74
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• 1973

The present paper concerns the age determination and growth of butter fish, Pampus argenteus from the southwestern waters of Korea by otolith reading. 743 specimens taken by stow-net in the southern part of the Yellow Sea and northeastern part of the East China Sea during the period from October 1972 to September 1973 were examined. Results of the study are summarized as follows: 1. Sex ratio of females to males was found to be 2:1. 2. Ring marks on the otolith were found to be formed twice a year, once during the period of January-May and the other time in September. 3. The Lee's phenomenon was observed on the otolith sample. 4. The relationship between the radius of otolith(R) and fork length(L) was found to be as follows: R=0.3069+0.0133L 5. Calculated fork length at the time of otolith ring formation are found to be as follows:I-ring,71.67mm; II-ring, 125.05mm; III-ring, 168.65mm; IV-ring, 201.74mm; V-ring, 225.80mm; VI-ring, 240.84mm. 6. Maximum fork length calculated according to the diagram of Walford's growth transformation was found to be 281.5mm. 7. Growth curve, when related to the von Bertalanffy's equation, was laid out as $L_{t}=281.5[1-e$^{-0.674(t-0.128)}]$

• Fisheries and Aquatic Sciences
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• 제10권1호
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• pp.30-36
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• 2007

We present age and growth data for Ilisha elongata, based on 363 specimens caught in 1999 and 2000 around Jeju Island and the southwest coast of Korea. Scale and ring radii of each ring group showed a direct one-to-one relationship, with ring radius increasing as scale radius increased. The relationship between fork length and scale radius was FL=39.553SR+60.935 for females, FL=39.474SR+54.026 for males, and FL=39.608SR+57.547 for both sexes. Monthly changes in the marginal index indicated that a new ring appears once each year (in July). Maximum age, mean age and mean fork length of fish were 10 years, 5.0 years, and 349mm, respectively. Von Bertalanffy's growth equations were $FL_t=495.4{\times}[1-\exp(-0.2586(t+0.6487))]$ for fork length (mm) and $W_t=1,112.5{\times}[1-\exp(-0.2586(t+0.6487))]^{2.874}$ for body weight (g) for both sexes. Monthly changes in the gonadosomatic index (GSI) indicated that the spawning period was in June and July, which corresponded closely with ring formation time. Differences in monthly GSI changes in 1999 and 2000 may be related to water temperature variation. Fecundity ranged from 5,664 to 176,290 eggs per individual (n=43, fork length 264-470mm). The relationship between fecundity(F) and fork length was $F=7.7{\times}10^{-7}{\times}FL^{4.9269}$.

• Journal of Ginseng Research
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• 제30권3호
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• pp.153-157
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• 2006

홍삼을 습점 또는 수침처리하여 원형을 복원한 후 경흔적 기산법과 나이테염색법을 이용하여 연근을 판별하였다. 경흔적 기산법은 뇌두를 $50^{\circ}C$에서 3일간 침지하여 뇌두의 뿌리 조직을 제거하면 줄기 조직만 남게 되어 연근판별의 정확도를 기할 수 있었다. 나이테 염색법은 홍삼 절편을 만들어 기존의 safranine에 의한 나이테 염색을 시도하였으나 나이테가 염색되지 않아 연근 판별이 불가능하였다. 한편 기계건조법은 홍삼 절편을 습점 처리하여 나이테를 건조시키던가 아니면 홍삼절편을 수침 처리하여 홍삼색소를 제거한 후 건조 사키면 나이테가 선명하게 들어나 연근판별이 가능하였다.