• Journal of Ecology and Environment
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• v.32 no.2
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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.

• Journal of the Chungcheong Mathematical Society
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• v.17 no.2
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• pp.191-196
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• 2004

• Bulletin of the Korean Mathematical Society
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• v.38 no.1
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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.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.4
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• pp.592-599
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• 2015

To investigate the characteristic of age and growth, samples of Megangulus venulosus were collected monthly by dredge in the coastal waters of Gangneung, Korea from January to December 2014. The age of M. venulosus was estimated by measuring the ring radius on the shell. Because the relationship between shell lengths and ring radii in each ring group was regressed well, each ring was considered as an annual growth ring. Based on the monthly variation of the marginal index (MI) of the shell length, it is assumed that the ring of this species was formed once a year during September and November. From the parameters calculated using the average length when the year ring was formed, the estimated von Bertalanffy growth equation were $SL_t=236.3(1-e^{-0.061(t+0.184)})$ in age.

• Journal of Ginseng Research
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• v.20 no.1
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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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• v.21 no.3
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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.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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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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• v.8 no.2
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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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• v.10 no.1
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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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• v.30 no.3
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• pp.153-157
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• 2006

This study was carried out to identify the age of red ginseng using the stem vestige counting methods and annual ring staining method. The samples were soaked, humidified, and restored before identifying the age. Root tissue was removed from rhizome after soaking treatment in $50^{\circ}C$ water for three days. It was found to be useful for precise identification of age. Safranine staining for counting the annual ring in sliced ginseng was not useful due to the poor staining. However, annual ring was clearly revealed whenr humidified sliced ginseng or soaked sliced ginseng were dried mechanically. These two method was useful to identify the age of red ginseng.