Korea forest Research Institute

Seoul, South Korea

Korea forest Research Institute

Seoul, South Korea

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The present invention relates to an electrochemical element and a method for producing same, the electrochemical element comprising: electrodes comprising a composite of active material and conductive material having a nanofiber structure; and a cellulose nanofiber separator combined with the electrodes. The electrochemical element according to the present invention obviates the need for separate binder and electrode current collector, has a stable interfacial surface due to the physical union of the separator and electrode, can assure superb mechanical and physical properties, and can maintain stable battery performance even against deformations due to a variety of external impact.

Kim K.H.,Seoul National University | Kim J.-Y.,Seoul National University | Cho T.-S.,Korea forest Research Institute | Choi J.W.,Seoul National University
Bioresource Technology | Year: 2012

The aim of this study was to investigate the influence of pyrolysis temperature on the physicochemical properties and structure of biochar. Biochar was produced by fast pyrolysis of pitch pine (Pinus rigida) using a fluidized bed reactor at different pyrolysis temperatures (300, 400 and 500°C). The produced biochars were characterized by elemental analysis, Brunauer-Emmett-Teller (BET) surface area, particle size distributions, field-emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FTIR) spectroscopy, solid-state 13C nuclear magnetic resonance (NMR) and X-ray diffraction (XRD). The yield of biochar decreased sharply from 60.7% to 14.4%, based on the oven-dried biomass weight, when the pyrolysis temperature rose from 300°C to 500°C. In addition, biochars were further carbonized with an increase in pyrolysis temperature and the char's remaining carbons were rearranged in stable form. The experimental results suggested that the biochar obtained at 400 and 500°C was composed of a highly ordered aromatic carbon structure. © 2012 Elsevier Ltd.

Kim Y.S.,University of British Columbia | Kim Y.S.,Korea forest Research Institute | Kadla J.F.,University of British Columbia
Biomacromolecules | Year: 2010

Copolymerization of N-isopropylacrylamide (NIPAM) with technical hardwood kraft lignin (HWKL) was achieved by atom transfer radical polymerization (ATRP) using a selectively modified lignin-based macroinitiator. The degree of polymerization (DP) of polyNIPAM graft side chains was affected by varying the ratio of the DMF/water solvent system from 5:0 to 0:5, and an estimated DP NIPAM of >40 was obtained using a ratio of 1:4 (v/v). The thermal decomposition temperature of the lignin-g-polyNIPAM copolymers significantly increased with increasing DPNIPAM. Likewise, the solubility of the lignin-g-polyNIPAM copolymers in water changed depending on copolymer structure. In both the water-soluble and suspended copolymers, at temperatures above 32 °C, the g-polyNIPAM component underwent the typical hydrophilic-to- hydrophobic transition, resulting in the precipitation of the copolymer. © 2010 American Chemical Society.

Choi W.I.L.,Korea forest Research Institute
Journal of Asia-Pacific Entomology | Year: 2011

Forest insect pests are one of the major disturbance factors in forest ecosystems and their outbreaks are expected to be more severe under the influence of global warming. Coleopterans are dominant among forest insects and their ecological functions include general detritivores, dead wood feeders, fungivores, herbivores, live wood feeders and predators. Ambrosia and bark beetles contribute to ecological succession of forests and, therefore, ecological functions of forests can be changed in response to their outbreaks. Mountain pine beetle (MPB) outbreaks are the most dramatic example of changes in the ecological functions of forest due to the outbreak of a forest insect pest altered by global warming. Composition of coleopteran species varies with latitude. However, composition of functional groups is consistent with latitude which indicates that resources available to beetles are consistent. In coleopteran communities, ambrosia and bark beetles can become dominant due to increases of dead or stressed trees due to the warming climate. This can also induce changes in the ecological functions of coleopterans, i.e. selective force to displace trees that have lower ecological fitness due to temperature increase. Therefore, recent increases in the density ambrosia and bark beetles offer a chance to study ecological processes in forests under the influence of global warming. © 2010.

This study investigated the fumigant toxicity of oriental sweetgum (Liquidambar orientalis) and valerian (Valeriana wallichii) essential oils and their components against the Japanese termite (Reticulitermes speratus). The fumigant toxicity of oriental sweetgum and valerian oil differed significantly according to exposure time. Oriental sweetgum showed toxicity at short exposure times (2 days), and the toxicity of valerian oil was high 7 days after treatment. The main constituents of oriental sweetgum and valerian oils were tested individually for their fumigant toxicity against Japanese termites. Among the test compounds, benzyl alcohol, acetophenone, 1-phenyl-1-ethanol, hydrocinnamyl alcohol, trans-cinnamyl aldehyde, trans-cinnamyl alcohol, cis-asarone, styrene, and cis-ocimene showed toxicity against Japanese termites 7 days after treatment. Hydrocinnamyl alcohol and trans-cinnamyl alcohol were found to be the major contributors to the fumigant antitermitic toxicity of oriental sweetgum oil. The acetylcholinesterase (AChE) inhibition activity of two oils and their constituents was tested to determine their mode of action. Only cis-ocimene showed strong AChE inhibition activity with an IC50 value of 0.131 mg/mL. Further studies are warranted to determine the potential of these essential oils and their constituents as fumigants for termite control. © 2014 by the authors.

The insecticidal activity of Piper nigrum fruit-derived piperidine alkaloid (piperine) and N-isobutylamide alkaloids (pellitorine, guineensine, pipercide and retrofractamide A) against female adults of Culex pipiens pallens and Aedes aegypti was examined. On the basis of 24-h LD50 values, the compound most toxic to female C. pipiens pallens was pellitorine (0.4μg) followed by guineensine (1.9μg), retrofractamide A (2.4μg) and pipercide (3.2μg). LD50 value of chlorpyrifos was 0.03g/. Against female A. aegypti, the insecticidal activity was more pronounced in pellitorine (0.17μg) than in retrofractamide A (1.5μg), guineensine (1.7μg), and pipercide (2.0μg). LD50 value of chlorpyrifos was 0.0014g. © 2012 Taylor & Francis Group, LLC.

Kim E.,Korea forest Research Institute | Park I.-K.,Korea forest Research Institute
Molecules | Year: 2012

Commercial plant essential oils obtained from 11 Myrtaceae plant species were tested for their fumigant antifungal activity against Aspergillus ochraceus, A. flavus, and A. niger. Essential oils extracted from Leptospermum petersonii at air concentrations of 56 × 10 -3 mg/mL and 28 × 10 -3 mg/mL completely inhibited the growth of the three Aspergillus species. However, at an air concentration of 14 × 10 -3 mg/mL, inhibition rates of L. petersonii essential oils were reduced to 20.2% and 18.8% in the case of A. flavus and A. niger, respectively. The other Myrtaceae essential oils (56 × 10 -3 mg/mL) only weakly inhibited the fungi or had no detectable affect. Gas chromatography-mass spectrometry analysis identified 16 compounds in L. petersonii essential oil. The antifungal activity of the identified compounds was tested individually by using standard or synthesized compounds. Of these, neral and geranial inhibited growth by 100%, at an air concentration of 56 × 10 -3 mg/mL, whereas the activity of citronellol was somewhat lover (80%). The other compounds exhibited only moderate or weak antifungal activity. The antifungal activities of blends of constituents identified in L. petersonii oil indicated that neral and geranial were the major contributors to the fumigant and antifungal activities. © 2012 by the authors.

Kwon T.-S.,Korea forest Research Institute
Journal of Asia-Pacific Biodiversity | Year: 2014

Based on data of ants that were surveyed by the same method in the Gwangneung forest in 1993 and 2009, influences of climate changes on ant fauna were examined. If temperature in a region is lower than the optimum temperature, then the occurrence of the species increase as temperature rises; and vice versa. As temperature rises, it will be more advantageous to the species with high optimum temperature than the species with low optimum temperature. The optimum temperature, therefore, will have a linear relation with change of occurrence. In this study, two hypotheses were examined. Although significant difference was not found, the decrease expected group (with lower optimum temperature) decreased more in occurrence compared with the increase expected group (with higher optimum temperature). A highland dominant species, Myrmica kotokui, occurred in 1993 but did not occur in 2009. Comparison of ant fauna between 1993 and 2009 indicate a possibility of influence of climatic warming, but this finding was not proved statistically. Copyright © 2014 National Science Museum of Korea (NSMK) and Korea National Arboretum (KNA).

The present invention relates to a composite separation film comprising cellulose fiber and silica, a method for manufacturing the separation film, and a secondary battery including the separation film, wherein the separation film has excellent thermal stability, dimensional stability, wettability and electrochemical stability and has a simplified manufacturing process such that the unit cost of production can be reduced.

The present invention relates to a composite separation film including a cellulose fiber and a silica, a method for manufacturing the separation film, and a secondary battery including the separation film, and the separation film has excellent thermal stability, dimensional stability, wettability, and electrochemical stability, and a manufacturing process thereof is simplified, and thus a production cost may be reduced.

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