• Plant Resources
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• 제3권2호
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• pp.138-147
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• 2000

This examination of vegetation is conducted from June to Oct. 1999 through on the spot survey, centering on the habitat of Abies koreana around Imgeolryeong, Jangteomok, and Jeseokbong in Mt Jiri and Yeongsil path and Seongpanak path in Mt. Halla. Species composition tables of the Abies koreana community by altitude and slope in Mt. Jiri and Mt. Halla are made based on the community composition tables examined in quadrat. The Abies koreana-Saso quelpaertensis community in a west slope of Mt. Halla is found that Abies koreana of 4-6m in height forms subtree layer and that of 8-9m in height the tree layer and it reflects a difference between community structure by slope and main composition species. While the tree layer of Abies koreana community is 12-14 in height around the area of 1,290-1,560m above the sea of Imgeolryong and path from Baekmudong to Jangteomok, it is 8-12m in height in the area of 1,680-1,780m above the sea of path from Jangteomok to Jeseokbong. It means that community structure depends on area and attitude. This study finds out that commonly appearing composition species similar to coverage and presence are Lepisorus thunberianus, Quercus mongolica, Solidago virga-aurea var. asiatica, Ligularia fischeri, Carex lanceolata, Clintonia udensis, Magnolia sieboldii, Betula ermani, Acer pseudo-sieboldianum. As soil environment of surveyed area, pH of surveyed spots is similar in Mt. Jiri and Mt. Halla, electrical conductivity is higher in Mt Jiri, and contents of organic matter is relatively higher in a west slope of Mt. Jiri and Mt. Halla and lower in their south and west slopes. Contents of organic matter and total nitrogen show that the area of 1,550m above the sea in a west slope of Mt. Halla is some higher. For pH and contents of total nitrogen and organic matter, Mt. Halla is higher than Mt. Jiri but for electrical conductivity, Mt. Jiri is relatively higher than Mt. Halla.

• 한국초지조사료학회지
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• 제17권3호
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• pp.249-256
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• 1997

A pulse-chase labeling of $^{15}N$ on winter rye (Scale cereale) and forage rape (Brassica napus) grown at $15^{\circ}C$ and $25^{\circ}C$ was carried out to determine the effects of low temperature on the uptake exogenous N and the remobilization of endogenous N. The growth rate of leaves and roots depressed at $5^{\circ}C$. AAer 9 days at $5^{\circ}C$, nitrogen content of leaves decreased to 20% on the average while that of roots increased to 12% compared with the plants grown at $25^{\circ}C$. Total content of $NO_3$- uptake 60m medium was 23.0 and 43.5 mg Nlplant, respectively, for winter rye and forage rape grown at $5^{\circ}C$ during 9 days. These values were corresponded to 59.3 and 26.1% lower uptake than those of $25^{\circ}C$. A large part of 1 5 ~ was distributed into leaves throughout time course in both of two species. The content of $^{15}N$ in leaves of winter rye at day 6 increased to 166 and 296 $\mu^{15}$N/plant compared with the initial value (day 0) in the plants grown at $5^{\circ}C$and $25^{\circ}C$ , corresponding to 90 and 163 $\mu$g N of remobilization h m roots into leaves during the fist 6 days. From 7 to 9 days, 75 and 52 $\mu$gN of outflow 6om leaves were occurred at $5^{\circ}C$ and $25^{\circ}C$. However, little remobilization of endogenous N was estimated in forage rape throughout the entire time course regardless of temperature treatment. Comparing two species studied, winter rye was much sensitively influenced by low temperature on the uptake of exogenous N and the remobilization of endogenous N.

• Animal Bioscience
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• 제36권4호
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• pp.671-678
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• 2023

Objective: Previous studies isolated the thermophilic ammonium-tolerant (TAT) bacterium Bacillus sp. TAT105 that grew in composting swine manure with the assimilation of ammonium nitrogen and reduced ammonia emissions during composting. Those studies also investigated the potential for applications of TAT105 to composting. It was observed that the concentration of TAT bacteria, phylogenetically close to TAT105, increased during composting. The objectives of this study were to identify the phylogenetic placement of these TAT bacteria and investigate their distribution in various composts. Methods: The phylogenetic placement of TAT105 was examined based on the sequence of 16S ribosomal RNA gene. The genomic DNA homology between TAT105 and the type strains of bacterial species that were phylogenetically close to TAT105 were examined by DNA-DNA hybridization. Moreover, the tolerances of these strains to NH₄Cl and NaCl were analyzed using a cultivation method. Concentrations of TAT bacteria in various composts were evaluated using an agar medium specific to TAT bacteria and polymerase chain reaction followed by restriction fragment length polymorphism analysis. Results: TAT105 was most closely related to Bacillus thermolactis and Bacillus kokeshiiformis. Many variants of these species have been detected in various environments, including composts. The type strains of these species displayed TAT characteristics that were similar to those of TAT105. Among the composts examined in this study, TAT bacteria were detected at high concentrations (10⁵ to 10⁹ colony forming units per gram of dry matter) in most of the composts made from cattle manure, swine manure, bark, and excess sludge. Conclusion: TAT bacteria comprised B. thermolactis, B. kokeshiiformis, and their phylogenetically close relatives. They were considered to be adaptable to composting of some certain materials, and a favorable target for searching for strains with some useful function that could be applied to composting of these materials.

• 환경생물
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• 제17권4호
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• pp.459-465
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• 1999

본 연구는 우리나라 습지의 주요 우점종인 갈대, 줄 및 애기부들을 대상으로, 자연습지에서 생육기 중에 시기와 횟수를 달리하여 지상부를 제거하는 것이 생산력과 영양염류 제거능에 미치는 영향을 규명하고자 하였다. 지상부 제거는 세 종 모두에서 지상부 생산력과 영양염류 흡수량을 증가시켰으며, 최대효과를 위한 시기와 횟수 및 효과의 정도는 종에 따라 차이를 보였다. 즉, 갈대는 1차년도 실험에서 6월 제거구의 연총생산력이 1,014g/$m^2$로서 대조구의 1.9배이었고, 2차년도에는 5월 제거구가 1,494g/$m^2$ 로서 대조구의 1.3배이었다. 줄은 8월 제거구의 생산력이 1,386g/$m^2$으로서 대조구의 1.2배, 애기부들은 6월과 8월의 3회 제거구와 8월 제거구의 생산력이 각각 1,670, 1,620g/$m^2$로서 대조구의 1.1~l.2배이었다. 영양염류 제거량에서 갈대는 질소와 인이 1차년도에서 대조구의 2.0배와 1.8배, 2차년도에서 각각 1.4배, 줄은 2.4배와 1.8배 그리고 애기부들은 1.8배와 1.9배로서 생산력의 증가비율보다 더 많은 영양염류를 제거하였다. 종합적으로 생산력과 영양염류 제거량 그리고 관리의 경제적인 측면을 고려할 때, 갈대는 5~6월과 10월의 2회, 그리고 줄과 애기부들은 8월과 10월의 2회 제거하는 것이 효과적인 것으로 판단한다.

• ALGAE
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• 제18권1호
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• pp.29-47
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• 2003

In order to investigate the distribution of dominant phytoplankton species in the coastal waters of Gori, Wolseong, Uljin and Younggwang, the standing crops of dominant species were studied during 1992-1996 and the relationships between standing crops and environmental variables were analyzed.The standing crops of diatom Skeletonema costatum, Thalassiosira decipiens, Chaetoceros debilis, Pseudo-nitzchia seriata, Paralia sulcata and dinoflgaellate Prorocentrum triestinum were on average from 16,373 to 118,549 cellso$l^{-1}$, from 11,180 to 210,313 cellso$l^{-1}$, from 23,341 to 55,889 cellso$l^{-1}$, from 6,784 to 15,766 cellso$l^{-1}$, from 342 to 41,596 cellso$l^{-1}$ and from 4,828 to 22,397 cellso$l^{-1}$ in the four study areas, respectively. The standing crops of Skeletonema costatum, Thalassiosira decipiens and Paralia sulcata were higher in Younggwang, while Chaetoceros debilis, Pseudo-nitzschia seriata and Prorocentrum triestinum were higher in Wolseong than other areas. The standing crops of silicoflgaellate Distephanus speculum were from 157 to 4,239 cellso$l^{-1}$ in the four study areas, showing an tendency increasing in Uljin. The abundance rates of Skeletonema costatum, Thalassiosira decipiens and Chaetoceros debilis were from 7.04 to 15.74%, from 6.95 to 33.69% and from 5.17 to 13.88% in the four study areas, respectivelyThe results of correlation coefficient between standing crops of dominant species and environmental variables show that phosphates were related with the distribution of dominant species in Gori, Uljin and Younggwang, while nitrogen compounds affected the distribution of dominant species in Wolseong. In addition, salinity and temperature affected the distribution of dominant species in Wolseong and Younggwang, respectively.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2000년도 추계학술발표회 초록집
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• pp.3-4
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• 2000

Many researchers are interested in the synthesis and characterization of carbon nitride and diamond-like carbon (DLq because they show excellent mechanical properties such as low friction and high wear resistance and excellent electrical properties such as controllable electical resistivity and good field electron emission. We have deposited amorphous carbon nitride (a-C:N) thin films and DLC thin films by shielded arc ion plating (SAIP) and evaluated the structural and tribological properties. The application of appropriate negative bias on substrates is effective to increase the film hardness and wear resistance. This paper reports on the deposition and tribological OLC films in relation to the substrate bias voltage (Vs). films are compared with those of the OLC films. A high purity sintered graphite target was mounted on a cathode as a carbon source. Nitrogen or argon was introduced into a deposition chamber through each mass flow controller. After the initiation of an arc plasma at 60 A and 1 Pa, the target surface was heated and evaporated by the plasma. Carbon atoms and clusters evaporated from the target were ionized partially and reacted with activated nitrogen species, and a carbon nitride film was deposited onto a Si (100) substrate when we used nitrogen as a reactant gas. The surface of the growing film also reacted with activated nitrogen species. Carbon macropartic1es (0.1 -100 maicro-m) evaporated from the target at the same time were not ionized and did not react fully with nitrogen species. These macroparticles interfered with the formation of the carbon nitride film. Therefore we set a shielding plate made of stainless steel between the target and the substrate to trap the macropartic1es. This shielding method is very effective to prepare smooth a-CN films. We, therefore, call this method "shielded arc ion plating (SAIP)". For the deposition of DLC films we used argon instead of nitrogen. Films of about 150 nm in thickness were deposited onto Si substrates. Their structures, chemical compositions and chemical bonding states were analyzed by using X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and infrared spectroscopy. Hardness of the films was measured with a nanointender interfaced with an atomic force microscope (AFM). A Berkovich-type diamond tip whose radius was less than 100 nm was used for the measurement. A force-displacement curve of each film was measured at a peak load force of 250 maicro-N. Load, hold and unload times for each indentation were 2.5, 0 and 2.5 s, respectively. Hardness of each film was determined from five force-displacement curves. Wear resistance of the films was analyzed as follows. First, each film surface was scanned with the diamond tip at a constant load force of 20 maicro-N. The tip scanning was repeated 30 times in a 1 urn-square region with 512 lines at a scanning rate of 2 um/ s. After this tip-scanning, the film surface was observed in the AFM mode at a constant force of 5 maicro-N with the same Berkovich-type tip. The hardness of a-CN films was less dependent on Vs. The hardness of the film deposited at Vs=O V in a nitrogen plasma was about 10 GPa and almost similar to that of Si. It slightly increased to 12 - 15 GPa when a bias voltage of -100 - -500 V was applied to the substrate with showing its maximum at Vs=-300 V. The film deposited at Vs=O V was least wear resistant which was consistent with its lowest hardness. The biased films became more wear resistant. Particularly the film deposited at Vs=-300 V showed remarkable wear resistance. Its wear depth was too shallow to be measured with AFM. On the other hand, the DLC film, deposited at Vs=-l00 V in an argon plasma, whose hardness was 35 GPa was obviously worn under the same wear test conditions. The a-C:N films show higher wear resistance than DLC films and are useful for wear resistant coatings on various mechanical and electronic parts.nic parts.

• 상하수도학회지
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• 제31권1호
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• pp.93-101
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• 2017

In this study, we investigated the correlation between the number of cyanobacterial species and the water quality factors after installation of Nakdong river weirs. Factor analyses of water quality factors were also performed. The results of correlations showed that there was no significant water quality with the cyanobacterial concentration but the correlation coefficient of nutrients increased from the upstream to the downstream. There was a significant correlation between W T and pH as important water quality factors for the growth of cyanobacteria. In the downstream region of Nakdong river, algae were more frequently detected than in the upstream region, and the blooms of algae species seem to be influenced by the higher pH and the influx of the phosphorus from the upstream tributaries. Nutrient concentration was higher in the downstream region than in the upstream region due to the effects of tributaries Geumho river and Nam river in Nakdong river. As a result of the factor analyses, nitrogen species were the principal factors in the upper region, and phorsphorus species were the principal factors in the downstream region.

• The Korean Journal of Ecology
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• 제15권4호
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• pp.355-363
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• 1992

Nitrate reductase activity(NRA) and induced NRA were compared in 4 species of moss ctenidium molluscum, homalothecium, tortella tortusa and neckera crispa collected from limestone in england. the NRA and dry weight of the c. molluscum were also measured after spraying with acidic deposition adjusted to ph 5.6, 4.6, 3.6 and 2.8 with one of two molar ratios of nitric to sulfuric acid, i.e. 1:0(N alone) and 1:2(1N+2S) for 20 days. All 4 species showed high NR leavels in the upper part of cut shoots and occurred maximum inducation of NRA within 6h. c. molluscum had the highest NRA levels among 4 species. after daily spraying of acidic deposition, NRA of c. molluscum was increased much more largely at ph 6 and ph 3.6 derived from N alone than from 1N+2S. However that was decreased at ph 2.8 derived both from N alone and 1N+2S . Decline of dry weight had occurred at ph 3.6 and 2.8 derived both from N alone and 1N+2S. Whereas substantial fertilization effect was observed at ph 4.6 derived from N alone. the data suggest that c. molluscum are able to utilize nitrate more effectivery than any other species, and NRA induction are more sensitive than growth response to nitrogen content of acidicdeposition in a short- term. however toxic effects was detected at high $NO_3$ supply and low phacidic deposition.

• 한국자기공명학회논문지
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• 제5권1호
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• pp.1-12
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• 2001

ZSM-5 gallosilicate molecular sieves was synthesized and cupric ion was ion-exchanged into the gallosilicate. The locations of Cu(ll) species in the framework and their interactions with various adsorbates were characterized by combined electron spin resonance(ESR) and electron spin echo modulation(ESEM) methods. It was found that in a fresh hydrated material, Cu(II) is octahedrally coordinated to six water molecules. This species is located in the channel intersections of two sinusoidal channels and rotates rapidly at room temperature. Evacuation removes some of these water molecules, leaving the Cu(II) coordinated to less water molecules and anchored to of oxygens in the channel wall. Dehydration produces two Cu(II) species, both of which are located in sites inaccessible to oxygen as evidenced by non-broadening of its ESR lines by oxygen. Adsorption of adsorbate molecules such as water, alcohols, ammonia, acetonitrile and ethylene on dehydrated CuNaH-ZSM-5 gallosilicate materials causes changes in the ESR spectrum of Cu(II), indicating the migration of Cu(II) into main channels to form complexes with these adsorbates there. Cu(II) forms a complex with two molecules of methanol, ethanol and propanol, respectively as evidenced by ESR parameters and ESEM data. Cu(II) also forms a square planar complex with four molecules of ammonia, based on the resolved nitrogen superhyperfine interactions and their ESEM parameters. Cu(II) forms a complex with two molecules of acetonitrile based on the ESR parameters and ESEM data. Interestingly, however, only part of Cu(II) interacts indirectly with one molecule of nonpolar ethylene based on ESR and ESEM analyses.

• Asian-Australasian Journal of Animal Sciences
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• 제17권7호
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• pp.942-946
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• 2004

This study aimed to examine the fermentation quality of a tropical Elephant grass (Pennisetum purpuereum) and temperate Italian ryegrass (Lolium multiflorum) forages ensiled additive of fermented juice of epiphytic lactic acid bacteria (LAB) and to determine what factor affects the fermentation characteristics of the crops. In both species cell walls neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents in silages were consistently decreased (p<0.05) with the addition of FJLB at ensiling more then Control treatment. The FJLB additive increased number of LAB (cfu) and lactate concentration in the silages in both species. The Control treatment without additive underwent a clostridial type of fermentation with traces of propionic, iso-butyric, n-butyric acids contents with higher (p<0.01) levels of volatile basic nitrogen (VBN %TN) and had appreciable decreased of nutrient in silages. FJLB treatment improved silage nutritive value with little contents of VBN %TN, ethanol and very small amount of dry matter (DM) and hemicellulose losses (p<0.05) between 2 to 5% and 7 to 3% respectively, in Elephant grass and Italian ryegrass species. The results in this study indicates that while among the factors affecting silage fermentation butyric type of fermentation was more pronounced in tropical elephant grass compared to the temperate Italian ryegrass, FJLB additive revealed a better silage fermentation products in both species.