• Journal of Korean Society of Forest Science
• /
• v.99 no.5
• /
• pp.726-735
• /
• 2010

Publications with the data on allometric equation, biomass and productivity of major oak forests in Korea were reviewed. Different allometric equations of major oak species showed site- or speciesspecific dependences. The biomass of major oak forests varied with age, dominant species, and location. Aboveground tree biomass over the different oak species was expressed as a power equation of the stand age. The proportion of tree component (stem, branch and leaf) to total aboveground biomass differed among oak species, however, biomass ranked stem > branch > leaf in general. The leaf biomass allocation over the different oak species was expressed as a power equation of total aboveground biomass while there were no significant patterns of biomass allocation from stem and branch to the aboveground biomass. Tree root biomass continuously increased with the aboveground biomass for the major oak forests. The relationship between the root to shoot ratio and the aboveground tree biomass was expressed by a logarithmic equation for major oak forests in Korea. Thirteen sets of data were used for estimating the net primary production (NPP) and net ecosystem production (NEP) of oak forests. The mean NPP and NEP across different oak forests was 10.2 and 1.9 Mg C $ha^{-1}year^{-1}$. The results in biomass allocation, NPP and NEP generally make Korean oak forests an important carbon sinks.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2006.04a
• /
• pp.320-321
• /
• 2006

• Journal of the Korean Ceramic Society
• /
• v.45 no.9
• /
• pp.507-511
• /
• 2008

A "C-sphere" specimen geometry was used to determine the failure strength distributions of a commercially-available bearing-grade silicon nitride ($Si_3N_4$) with ball diameters of 12.7 and 25.4 mm. Strengths for both diameters were determined using the combination of failure load, C-sphere geometry, and finite element analysis and fitted using two-parameter Weibull distributions. Effective areas of both diameters were estimated as a function of Weibull modulus and used to explore whether the strength distributions predictably scaled between each size. They did not. That statistical observation suggested that the same flaw type did not limit the strength of both ball diameters indicating a lack of material homogeneity between the two sizes. Optical fractography confirmed that. It showed there were two distinct strength-limiting flaw types common to both ball diameters, that one flaw type was always associated with lower strength specimens, and that a significantly higher fraction of the 25.4-mm-diameter C-sphere specimens failed from it. Predictable strength-size-scaling would therefore not result as a consequence of this because these flaw types were not homogenously distributed and sampled in both C-sphere geometries.

• Journal of the Korean Wood Science and Technology
• /
• v.23 no.2
• /
• pp.26-31
• /
• 1995

Acetylcellulose(AC) was prepared with steam exploded wood(EXW) and EXW after delignification with sodium chlorite, pine (Pinus densiflora) and oak (Quercus mongolica) woods. The color of acetylated pine and oak exploded wood was brown, degree of substitution(D.S) of pine was 1.47~2.09, and this of oak was 1.49~2.29. The hemicellulose content of acetylated pine and oak exploded wood was 0~3.4% and 1.49~11.3%, individually. The degree of substitution of acetylated wood prepared from delignified EXW in the pine and oak wood was 0.50~0.71 and 0.70~0.88, individually. Hemicellulose content of acetylated EXW with sodium chlorite after delignification in the pine and oak wood was less than 1% and 0.6~2.5%. The color of acetylated wood after delignification was white. IR-spectra of acetylated pine and oak EXW after delignification were found that peaks at around 1740$cm^{-1}$ and 1200$cm^{-1}$ increase markedly, due to ester carbonyl group.

• Progress in Superconductivity
• /
• v.4 no.1
• /
• pp.10-13
• /
• 2002

We report the effect of Ca doping in $YBa_2Cu_3O_{7-\delta}$ (YBCO) thin films grown on the Rolling- Assisted, Biaxially Textured Substrates (RABiTS) with the architecture of $CeO_2/YSZ/CeO_2/Ni$. Critical currents of bilayer and trilayer structures of $YBCO/Y_{0.7}Ca_{0.3}Ba_2Cu_3O_{7-\delta}$/(YCaBCO) as well as undoped YBCO for comparison have been measured in a wide range of temperatures and fields. For $6-8^{\circ}$ grain boundaries, 30% Ca-doping in bilayer structure enhances $J_c$ as high as 35%. The enhancement is larger at low temperatures and at magnetic fields. On the other hand, 30% Ca-doping in trilayer structure reduces $J_c$ as high as 60%. Combined with slightly lower $T_c$, this indicates that Ca is overdoped in this structure and degrades GBs.

• The Korean Journal of Ecology
• /
• v.1 no.2
• /
• pp.57-65
• /
• 1977

The biomass and net production of alder and oak trees was estimated by allometric method. The productivity of the two stands of alder and oak was obviously different judging from the rate of photosynthesis productive structure and vertical distribution of light. The amounts of net photosynthesis under the saturated light were 2.31, 1.42mg $CO_2/dm^2\cdot$hr. in the sun and shade leaves of alder tree and 1.58, 0.84mg $CO_2/dm^2\cdot$hr in that of the oak, respectively. Total annual respiration loss calculated from the respiration measured at $25^{\circ}C$ and the mean air temperature from every 10 days were 13.56ton/ha.yr in the alder stand and 19.83 ton/ha.yr in the oak. The productive structure and the vertical distribution of light in the stand were assumedly more effective to produce dry matter in the oak stand than in the alder. The biiomasses measured in 1975 and 1976 were 51.51 and 56.82 ton/ha in the alder stand and 73.35, 86.77 ton/ha in the oak one, respectively. Annual net production and gross production were 8.56 and 22.12 ton/ha.yr in the alder stand but those were 17.90 and 37.74 ton/ha.yr in the oak stand. The ratios of respiration to gross procution (R/Pg) were prespectively 0.61 and 0.53 inthe alder and oak stands. Efficiencies of solar energy utilizaztion of net production during the growing season(May-Oct.) were 0.67 and 1.40% and those of gross production were 1.72 and 2.94% in the alder and oak stands respectively.

• The Korean Journal of Food And Nutrition
• /
• v.34 no.1
• /
• pp.79-87
• /
• 2021

This study was conducted in order to investigate the quality characteristics of MBA wine resulting from treatment with different oak barrel maturation methods. This study focused on the maturation of wine in five different types of barrels, including a stainless-steel maturation barrel, a foreign medium-toasted oak barrel, and domestic light, medium and heavy toasted oak barrels, and looked at the resulting differences in quality characteristics between the wines. All oak barrels used for this study had a capacity of 100 liters. The results of the study revealed that the pH content increased by up to 3.86~3.93% after 9 months, and then decreased after this point. The total anthocyanin content increased up to 152.52~174.95 mg/L during a 6 month maturation period, and thereafter began decreasing in concentration, with overall anthocyanin levels tending to be higher after maturation in foreign oak barrels. Overall, functional elements tended to measure higher after maturation in foreign oak barrels as opposed to maturation in domestic oak barrels. Therefore, these results indicate that it is necessary to improve the production of domestic oak barrels in the future in order to reliably produce wines with higher levels of functional elements.

• The Korean Journal of Mycology
• /
• v.6 no.2
• /
• pp.31-36
• /
• 1978

The study has been carried out to invetigate the possibility of oak mushroom (shiitake) cultivation on Ban Oak (Quercus incana) growing naturally in Simlaregion, India. The survival and growth of oak mushroom mycelium and fruit body formation on Q. incana as well as the composition of the log were compared with that of Bristle-tooth oak (Q. serrata) which are being used for mushroom cultivation in Korea. The results are summarized as follows. 1. The content of alcohol-benzen extract, NaOH extract, NaOH extract and ash were higher in Q. incana than in Q. Serrata. While cellulose and pentosan were less in the formers. 2. The mycelial growth of oak mushroom were more rapid on sawdust medium of Q. Serrata than on Q. incana. However the mycelial growth on the later were more compact. 3. The mycelial growth of oak mushroom were more rapid on the logs of Q. serrata than Q. incana. The mycelium survived well on both two species, and no difference in the survival rate of mycelium were observed. 4. The first fruit bodies on logs of Q. Serrata and Q. incana were appeared 16 months inoculation of spawn. 5. In view of the above results. it seems that the cultivation of oak mushroom (shiitake) on Ban oak (Q. incana), growing in India, is possible.

• Journal of Korean Society for Atmospheric Environment
• /
• v.33 no.1
• /
• pp.31-44
• /
• 2017

The aim of this study is to evaluate the accuracy and variability of the oak pollen concentrations over the Seoul metropolitan region (SMR) simulated by the Community Multiscale Air Quality (CMAQ)-based pollen dispersion model, which is the CMAQ-pollen model integrated with the improved oak pollen emission model(PEM-oak). The PEM-oak model developed is based on hourly emission flux parameterization that includes the effects of plant-specific release, meteorological adjustment, and diurnal variations of oak pollen concentrations. A 33 day-run for oak pollen simulation was conducted by the CMAQ-pollen model with a 3 km spatial resolution for the SMR during the 2014 spring pollen season. Modeled concentrations were evaluated against the hourly measurements at three Burkard sampling sites. Temporal variations of oak concentrations were largely well represented by the model, but the quantitative difference between simulations and measurements was found to be significant in some periods. The model results also showed that large variations in oak pollen concentrations existed in time and space and high concentrations in the SMR were closely associated with the regional transport under strong wind condition. This study showed the effective application of the CMAQ-pollen modeling system to simulate oak pollen concentration in the SMR. Our results could be helpful in providing information on allergenic pollen exposure. Further efforts are needed to further understand the oak pollen release characteristics such as interannual variation of the oak pollen productivity and its spatio-temporal flowering timing.

• Mycobiology
• /
• v.42 no.3
• /
• pp.279-281
• /
• 2014

Severe bark decay disease was observed on oak logs at a shiitake cultivation farm in Geochang-gun, Gyeongnam province. The symptoms observed were fruiting bodies that had developed on the top and side surface of oak logs. As a result, the bark came off easily exposing the sapwood. Slime mold specimens collected from oak logs showed developing fruiting bodies comprising of stalks, hypothallus, capillitium, and columella, and the causal agent of bark decay disease was identified as Stemonitis splendens on the basis of morphological characteristics. To our knowledge, this is the first report of Stemonitis splendens causing bark decay of oak logs used for shiitake mushroom cultivation in Korea.