• Journal of Ginseng Research
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• v.12 no.1
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• pp.1-10
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• 1988

Panax ginseng seedlings were grown at various temperature regimes from 15 to $30^{\circ}C$ for 19 days under dark and the linear relationship between various regrowth efficiencies and thermal stress indices, cumulative superoptimum temperatures corrected with factors. Gross growth efficiency(shoot weight l root weight loss) was 37.5 % at the optimum temperature $15^{\circ}C$/$15^{\circ}C$, and 12.3% at the highest temperature, $30^{\circ}C$/$30^{\circ}C$ while net growth efficiency (shoot weight + Sm)l(root loss-Rm), which corrected by maintenance respiration for shoot(Sm) and root(Rm) was 39.6% and 16.7 at optimum and highest temperature respectively. All growth efficiencies showed negative correlations (p = 0.001) with all thermal stress indices and negative(p = 0.001) with shoot growth(St). When growth temperature difference in a day was nil or above $15^{\circ}C$ growth efficiency decreased greatly. Thermal stress indices showed negative correlation with root dry matter loss(RDL) but positive with Rm. St showed positive correlation with RDL. Thermal stress appeared to inhibit substrate supply for shoot growth resulting in the extremely low growth efficiency comparing with other crops that seems to be main rate limiting factor of slow growth, Thus it is necessary that growth efficiency and thermal stress must be elucidated in terms of metabolic pathway.

• Korean journal of applied entomology
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• v.21 no.4 s.53
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• pp.200-206
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• 1982

A computer simulation model was constructed to explore the phonology of the Striped Rice Borer, Chilo suppressalis (Walker), in Korea. The phenological system model based on the concept of distributed time delay was written in the computer program 'INSECT' and simulated with the estimated parameters of the effective day-degrees (DEL) and the order of time delay (K) for determining the validity of the system model. The accumulated emergence curves obtained from the phenological model were slightly different from the observed light trap data at the early and late stage of the moth emergence in 1978. The differences between observed and simulated $50\%$ emergence date were five to six days in the locations of Suweon and Chuncheon, while it was only two to three days in Iri, Daegu, Boseong, and Milyang. The phenological model should be further improved for simulation of field population changes by adding the information of the time delay process in each developmental stage, the age distribution of overwintered population, and the limiting factors of the borer mortality.

• Journal of the Korean Chemical Society
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• v.10 no.4
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• pp.166-174
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• 1966

The multistep mechanism of photosensitized curing reaction cinnamoylated photosensitive polymer is proposed from the energy level diagram of cinnamic acid and sensitizer, and from the fact that excess of sensitizer brings the sensitivity to a limiting value etc. Various factors which have effects on the ability of sensitizer are also discussed. The mechanism involves following steps: activation to the first excited singlet states of cinnamoyl group(C) and sensitizer(S) by their absorption of photon, their intersystem crossing to the lowest triplet state, bimolecular internal quenching by formation of excimer of sensitizer, triplet excitation energy transfer and intermolecular addition between cinnamoyl group in ground state and that in triplet state. The rate equation derived from this mechanism is $-\frac{d[C]}{dt} = \frac{K_1[C]}{K_2 + [C]}[\frac{I^c_{abs}}{K_3 + [S]} + \frac{K_4[C]}{(K_5 + [C])(K_6 + [S])}(I^s_{abs} + \frac{K_7I^c_{abs}[S]}{K_8 + [S]})]$ where $I^c_{abs}\;and\;I^s_{abs}$: the rates of absorption of photon by cinnamoyl group and sensitizer $K_n$: Constants. It is proved with the cinnamate of poly(glyceryl phthalate)(PGC) in the absence of sensitizer using the infrared analytical method and successfully applied for the experimental data reported on the effects of the degree of cinnamoyl esterification and the concentration of sensitizer upon the sensitivity.

• Journal of muscle and joint health
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• v.4 no.2
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• pp.197-220
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• 1997

The lack of a comprehensive theory describing the mechanism of adaptation scientifically has been one of the limiting factors for the development of nursing intervention of patients with chronic illness. Since Roy's theory provides the general conceptual framework depicting adaptation process with structural stimuli and control mechanism, it is appropriate to understand the process of adaptation. But in Roy's theory, the propositions about cognator and regulator as control mechanisms are not clearly defined. For this reason, most of the previous researches applying the Roy's theory have disregarded the study of cognator and regulator. For the patients with chronic illness such as rheumatoid arthritis, it was reported that adaptation states were different for the same stimuli due to the difference of the control mechanism. Moreover in nursing it is important to identify the control mechanism which can be and must be intervened by nurses. It was the Lazarus and Folkman's theory that proposed the control mechanism. They suggested that individual differences in the reaction against the perceived stress are due to the difference in appraisal and coping. Therefore, the synthesis of Roy's and Lazarus and Folkman's propositions might help to clearly understand the mechanism of adaptation. From this point, a theoretical framework has been developed and tested. The subjects were the 297 patients who had been diagnosed rheumatoid arthritis and attended the outpatient clinic. A hypothetical prediction model of adaptation was tested by the covariance structure analysis with PC-LISREL 7.13. As a result, the overall fit was good($x^2$=78.83, p=0.00 ; GFI=0.96 : AGFI=0.90 ; RMR=0.04) for the hypothetical model. In the final model added GA(5, 1), the overall fit was increased ($x^2$=57.82, p=0.003 ; GFI=0.97 ; AGFI=0.93 : RMR=0.036). Except the fact that illness symptoms affected physical adaptation directly, it was supported that focal and contextual stimuli affected physical and psychosocial adaptation through appraisal and coping. Therefore, it was asserted that the synthesis of two theory's propositions was appropriate. So this model would be useful for the theoretical framework in the nursing practice. And this study synthesizing and testing the theory might contribute to establish nursing's scientific base.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.2
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• pp.82-88
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• 2017

MET (Microbial Electrochemical Technology), such as MFC (Microbial Fuel Cell) and MEC (Microbial Electrolysis Cell), is a promising technology for producing sustainable biogas from an anaerobic digester (AD). At current stage, however, the most likely limiting factors, large internal resistances, should be overcome for successful scale up of this technology. Various researchers reported that application of electrode materials containing high current density, increase of ion strength and conductivity, configuration of electrode are good methods for minimizing internal resistances. Recently, stainless steel is receiving great attention because of not only high performance and durability but also low cost. Therefore, in this study, we evaluate electrochemical characteristics and biogas production rate using various electrode materials and configuration (graphite carbon coated with catalysts ($GC-C_M$) or not (GC), stainless steel mesh (SUS-M) and plate (SUS-P)). As the results, current densities of $GC-C_M$, GC, SUS-P, SUS-M were 2.03, 1.36, 1.04, $1.13A/m^2$, respectively. Methane yields of $GC-C_M$, GC, SUS-P, SUS-M were 0.27, 0.14, 0.19, 0.21 $L-CH_4/g-COD_{rem}$., respectively. Stainless steel shows high current density and methane yield, which are similar as graphite carbon coated with catalysts.

• Journal of Wetlands Research
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• v.15 no.1
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• pp.71-78
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• 2013

An exceptional case of inhabitation of a Sphagnum sp. was firstly confirmed at abandoned paddy terrace (APT) wetland in Ansan. Water sampling for analyzing of physicochemical conditions including nutrients such as NP, $Ca^{2+}$ and $Mg^{2+}$ was performed and the vegetation map for distribution of Sphagnum sp., topographical map, and flora list for companion species were made at field in June 2011. From the results, the Sphagnum sp. in the study site was identified as S. palustre and it covered about 8% of the wetland cover of 3,200 $m^2$. Most distributions of S. palustre were observed at tussock structures as micro-topography by sedges and grasses within a wetland (74%) and the shaded slope area under Pinus densiflora's canopy in wetland boundary (26%). Despite that APT in Ansan is relatively lower wetland in altitude than high moors, the contents of calcium ($0.45{\pm}0.2$) and magnesium ($1.48{\pm}0.6$) ion which are critical limiting factors for Sphagnum spp. were very low levels as well as NP ($PO_4$-P, $0.02{\pm}0.0$; $NO_3$-N, $0.25{\pm}0.3$; $NH_4$-N, $0.06{\pm}0.1$) and it could enable the inhabitation of S. palustre in lower APT.

• Korean Journal of Microbiology
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• v.34 no.4
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• pp.188-193
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• 1998

The authors examined the variations of environmental factors, the distributions of cyanobacteria, heterotrophic bacteria, and microorganisms that inhibit the growth of Anabaena cylindrica according to development and extinction of cyanobacterial bloom at a site in Daechung Dam reservoir. And certified the relationship between each other. Water temperature variated in a typical pattern. pH and concentrations of dissolved oxygen and chlorophylla was high in bloom period, and lowered with the decline of bloom. Phosphorus played as a growth-limiting factor at this study site. Total nitrogen concentration increased during blooming period, which indicated that nitrogen has been fixed by aquatic organisms such as cyanobacteria. Cyanobacteria distributed from June 17, and such cyanobacterial species as Anabaena spp., Aphanizomenon spp., Microcystis spp., Oscillatoria spp. and Phormidium spp. was detected during study period. Anabaena spp. distributed relatively highly distributed from July 23 to September 22, and disappeared completely at September 29. Heterotrophic bacterial and cyanobacterial populations varied inverse-proportionally. There was a relevancy between the variations of Anabaena spp., heterotrophic bacteria, and microorganisms that inhibit the growth of Anabaena cylindrica. Microorganisms that inhibit the growth of Anabaena cylindrica distributed from early growth phase of Anabaena spp. population to immediately after the extinction of Anabaena spp. With the population of Anabaena cylindrica growth-inhibiting microorganisms decreasing, increases of heterotrophic bacterial population followed it. Thease results indicate that microorganisms have a part in the extinction of cyanobacterial bloom, especially at its destroying period.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.3
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• pp.139-144
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• 2005

To investigate the long-term variation of water qualities, we have daily monitored physio-chemical characteristics of surface water in the Geum River estuary from June 1996 to April 2004. We found that the water qualities were determined by three dominant factors : 1. fluvial input from Geum River ($28.3\%$), 2. chemical processes such as nitrification and phosphate addition originated from sediment resuspension and domestic sew- age input ($18.6\%$), 3. biological processes such as nutrient consumption by primary producers ($13.5\%$). The factor 1 (fluvial input) effectively affected the water quality of the estuary particularly during the normal or low river discharge. The factor 2 (chemical processes) and the factor 3 (biological processes) showed distinct seasonal differences due to their relative strengths of biological activities. The factor 3 was a governing parameter during the period of spring algal bloom in 2004. For the spring period, an empirical equation derived from the multi-regression analyses showed that the in-situ chlorophyll-a distributions in the estuarine water were successfully simulated by the phosphate concentrations and N/P ratios. Therefore we suggest that phosphate functions as a limiting factor for the primary productivity in the Geum River estuary for the dry season, especially during spring.

• Korean Journal of Ecology and Environment
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• v.47 no.spc
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• pp.74-82
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• 2014

A perennial plant species of Ranunculaceae, Pulsatilla tongkangensis is a very rare species only found in limestone vegetation of South Korea. It is not only rare but also has great value as a horticultural resource, thus resulting in serious problems of overexploitation and habitat disturbance. For the conservation of the rare species and its development as a resource, the study was conducted with the following three aims: first, to investigate any new geographical distribution of the species; second, to identify the site condition and vegetation structure of its habitat; and third, to compare the ecology of P. tongkangensis in other microhabitats such as rock, slope and ridge area. A new distribution was found in limestone vegetation at Danyang-gun, Chungcheongbuk-do. It was, therefore, confirmed that the distribution of P. tongkangensis exactly coincides with the area of distribution of limestone, indicating a possibility that the species might be a calcicole. 87% of the microhabitats found in rocks. Compared to P. tongkangensis, at ridges or slopes, number of P. tongkangensis plants were few in rocks. It is possibly due to the lack of microhabitats that could settle in rocky areas. Once established on rocks, however, plants grew large enough to flower with higher number of leaves and flowers per plant, resulting in higher flowering rate on rocky areas. Cracks in/between rocks are likely to be safe places for the plants with favorable light conditions, abundant fine particles to root down and reduced competition for resources. Yet, further research is necessary in terms of determining whether the species is indeed a calcicole, whether other limiting factors work in its establishment stage, and genetic diversity exists in the population.

• Asian Journal of Turfgrass Science
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• v.23 no.2
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• pp.353-360
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• 2009

Phosphorus (P) is one of the essential elements of the phospholipids that are involved in the formation of plant cell membranes. Phosphorus is highly immobile in soils and is often a limiting nutrient for plant growth. Phosphorus mobility and availability varies with several factors such as application frequency, placement in the soil, and the amount of irrigation or precipitation. This study was conducted to evaluate the effect of P applications at level of 0, 146, and 293 $kg{\cdot}ha^{-1}$ at four mixing depths (0, 7.6, 15.2, and 22.9 cm )on the growth and establishment of Kentucky bluegrass (Poapratensis L.) in a sand-based system.Grass clipping samples were collectedevery two weeks, dried, and weighed. Total root dry weight, root organic matter, and tissue content of P were measured at the end of the study. Leachate was collected weekly and analyzed for total P concentration. No difference was found between application of P to the surface and to the 7.6 cm mixing depth. However, surface application with 146 and 293 kg $P{\cdot}ha^{-1}$ produced 8-10% and 16-20% more P in tissue than subsurface applications, respectively.