• Journal of the Korean Wood Science and Technology
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• v.29 no.3
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• pp.92-98
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• 2001

Allelopathic effects of the cork tree (Phellodendron amurense Rupr.) on several crops and soil miro-organisms were assessed using germination bioassay and antimicrobial assay, and allelochemicals were identified. In a germination bioassay, extract of cork tree inhibited at high concentration on germination of several crop seeds such as cabbage, lettuce, and cucumber. However, aqueous extracts inhibited powerfully growth of test organisms such as Streptococus aureus, S. aureus, S. typhimurium, and E. coli as bacteria, and Candida albicans as yeast, and Botrytis cineria and Alternata alternaria as fungi.. The cork tree extract showed strong antimicrobial activities against isolated soil fungi. The allelochemicals were separated using Silica gel, Sephadex LH-20 gel column chromatography and HPLC. The substances were analyzed by UV spectrometry and EI-mass spectrometry. The active allelochemicals were identified as isoquinoline alkaloids, berberine and palmatine.

• Journal of the Korean Wood Science and Technology
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• v.28 no.4
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• pp.1-9
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• 2000

This experiment was accomplished to investigate antioxidative activity of Korean mistletoe by organic solvents partitioning of methanol extact of 3 Korean mistletoes, fractionationing on column chromatography, and evaluation the reduction of a free radical ${\alpha}$,${\alpha}$-diphenyl-${\beta}$-picrylhydrazyl. Butanol partition of Loranthus yadoriki MeOH extract showed higher electron donating ability than ${\alpha}$-tocopherol. It was thought phenolic compounds including gallic acid account for antioxidative activity, on execution sub-fractionation, electron donating ability evaluation, and GC/MS analysis, but further studies on what are major actives must be investigated exactly.

• Journal of Forest and Environmental Science
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• v.23 no.2
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• pp.87-91
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• 2007

The needles of L. kaempferi was extracted with 95% ethanol and successively partitioned with n-hexane, $CH_2Cl_2$ and EtOAc. Repeated column chromatography on the EtOAc and $H_2O$ soluble fractions gave three flavan-3-ols, one flavone glycoside, six flavonol glycosides and one lignan derivative. Their structures were elucidated on the basis of chemical and spectroscopic evidences. The antioxidant activities of the isolated compounds were evaluated by DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging method. Flavan compounds indicated good antioxidative potentials compared with BHT (butylated hydroxytoluene) and ${\alpha}$-tocopherol as controls. In the anti-inflammatory test on most of the isolated compounds, NO (nitric oxide) assay against the RAW 264.7 (Mouse Macrophage) showed similar inhibitory potentials to NO production of the control. The cytotoxicity was determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and most of the isolated compounds indicated no toxicity in various concentration.

• Journal of the Korean Wood Science and Technology
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• v.26 no.4
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• pp.56-60
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• 1998

The bark of Fraxinus rhynchophylla, one of ash trees grown in domestic, was collected, extracted with acetone-$H_2O$(7:3, v/v) and freeze dried to give 50g of ethylacetate soluble powder. A portion of the freeze dried powder was chromatographed on a Sephadex LH-20 and a TSK 40F column using a series of aqueous methanol and ethanol-hexane mixture as eluents. The extractives contained a large amount of coumarin derivatives in addition to a small amount of ester compounds such as ligstroside and oleuropein which have not been isolated from this tree species yet. Some spectrometric analyses such as NMR and FAB-MS including TLC were performed to identify the structures of the isolated ester compounds.

• Journal of the Korean Wood Science and Technology
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• v.21 no.3
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• pp.82-86
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• 1993

은행나무 추출물의 생리활성에 대한 실험결과, 그 추출물이 GAG release에 의한 IL-1의 억제효과(87%)를 나타냄을 관찰하였다. 그 추출물을 chromatography로 분리한후 분광학적 분석을 이용하여 그 함유물질들이 anarchardic acid 및 그와 유사한 페놀성 물질임을 밝혔다. 각 성분에 대하여 활성효과를 다시 실험한 결과, 주성분인 IIIb와 IIIc는 활성효과를 보이지 않았으며, 단지, 소량물질인 Va와 Vb만이 중간 정도의 효과(각각 43과 55%)를 나타내었다. 이 결과에 의하면, 은행나무의 추출성분이 IL-1의 억제효과를 분명히 나타내나, 그 효과가 주성분에 기인하는 것이 아님을 보여 주었다.

• Journal of the Korean Wood Science and Technology
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• v.30 no.3
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• pp.12-17
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• 2002

The extracellular invertase (EC 3.2.1.26) (Candida utilis) preparation was obtained from the liquid medium after desalting and freeze drying. This prepared enzyme was used for the comparative purification on 4 activated matrices by liquid column affinity chromatography method. In this method there were used controlled porous glass (CPG) silanized covalently activated by keratin, silanized silica gel and silica gel covalently covered by keratin. It was found that the invertase purification process was better using both CPG matrices (silanized CPG and keratin activated CPG) than these with two silica gel supports. Also the elution coefficient of the invertase from the two CPG columns was about 93 to 94%. Two silica gel supports found to be superior in terms of purification efficiency. The invertase purification process was confirmed by PAGE electrophoresis.

• Journal of the Korean Wood Science and Technology
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• v.35 no.6
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• pp.135-144
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• 2007

The dried barks of Maackia amurensis were ground, extracted with 95% EtOH, concentrated, and fractionated with a series of light petroleum ether, dichloromethane, ethyl acetate and water on a separatory funnel. Each fraction was concentrated, then a portion of dichloromethane and ethyl acetate soluble was chromatographed on a Sephadex LH-20 and silica gel 60 column using a various solvent system as eluents. The isolated compounds were identified by cellulose TLC, $^1H-$, $^{13}C-NMR$, COSY, NOESY, HMQC, HMBC, FAB and EI-MS. The structures were determined as: 7-O-$\beta$-D-glucopyranosyl-4'-methoxyisoflavone, 7-O-$\beta$-glucopyranosyl(1'''->6'')-$\beta$-D-glucopyranosyl-4'-methoxyisoflavone, 7-O-$\beta$-D-glucopyranosyl(1''''->6''')-$\beta$-D-glucopyranosyl(1'''->6'')-$\beta$-D-glucopyransoyl-4'-methoxyisoflavone, 7-O-$\beta$-D-glucopyranosyl-4', 6-dimethoxyisoflavone. The Free radical scavenging activity using DPPH of the isolated compounds were similar with that of BHT but lower than of $\alpha$-tocopherol.

• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.535-543
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• 2017

For column-beam gussets of wooden structures, slit-processed members inserted with a steel plate are used in general. In this study, a rigid portal frame bonded with a joint was fabricated and a semi-rigid portal frame was fabricated by making a wooden gusset, a replacement for steel plate, of which a half was integrated into the column member and the other half was joined with the beam member by drift-pins. The lateral strength performance of the wooden portal frame was compared with that of the steel plate-inserted joint portal frame. The lateral strength performance was evaluated through a perfect elasto-plasticity model analysis, sectional stiffness change rate, and short-term permissible shear strength. As a result of the experiment, the maximum strength of the rigid portal frame was lower than that of the steel plate-inserted joint portal frame. The yield strength and ultimate strength were calculated as 0.58 and 0.48, respectively, but the measurements of initial stiffness and cumulative ductility improved by 1.35 and 1.1, respectively. As a result of the perfect elasto-plasticity model analysis of the semi-rigid portal frame, the maximum strength was lower than that of the rigid portal frame, but the toughness after failure was excellent. Thus, the ultimate strength was higher by 1.05~1.07. The steel plate-inserted portal frame showed rapid decrease in stiffness with the progress of repeated tests, but the stiffness of the portal frames with a wooden joint decreased slowly.

• Journal of the Korean Wood Science and Technology
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• v.16 no.2
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• pp.79-89
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• 1988

This experiment was carried out to investigate the difference of compositions between petroleum ether extract and its tall oil in Pinus rigida Mill. xylem and to obtain the basic data on effective extraction and its utilization of by-product, resin and fatty acid, when pulp making. After both petroleum ether extract from wood meal and its tall oil in pitch pine were separated to the resin and fatty acid by using DEAE-Sephadex and aluminum oxide column, these were analyzed with gas chromatograph. The results obtained were as follows: 1. Fatty acids contained as ester form in living trees were varied by peroxide of organic solvent in petroleum ehter extraction and cooking chemicals in cooking. 2. Pimaric-type acid was eluted earlier than abietic-type acid in resin acids and the fewer the carbons, the earlier the elution in fatty acids. 3. The retention time of SE-30 column was even smaller than that of OV-101 column but the relative retention time obtained by using methyl pimarate and methyl stearate as internal standard was nearly identical. 4. Both petroleum ether extract and tall oil mainly consisted of resin acids, expecially abietic-type acid. 5. Tall oil had more fatty acid but less resin acid than petroleum ether extract. Also, the content of unidentified materials was increased owing to the isomerization and the shift of double bond position in unsaturated fatty acids by high temperature and cooking chemicals when cooking.

• Journal of the Korean Wood Science and Technology
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• v.38 no.3
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• pp.199-204
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• 2010

Members used for the Korean traditional joints have been processed by handicraft, especially with domestic red pine species. Dovetail joint is most commonly used in woodworking joinery and traditional horizontal and vertical connections. It is able to be processed much easier to cut by handicraft and machines. However, although it is processed straight forwards, it requires a high degree of accuracy to ensure a snug fit. Also, tenons and mortises must fit together with no gap between them so that the joint interlocks tightly. A few scientific studies on the dovetail joints have been conducted so far. For the effective applications of traditional joints and domestic plantation wood species, dovetail joints were assembled by larch glulam members processed by machine pre-cut. To identify the tensile properties of through dovetail joints, larch glulam with 150 150mm in cross section were prepared. Furthermore, various geometric parameters of dovetai joints such as width, length, and tenon angle, were surveyed. The ends in the mortise was cracked mainly at a low strength level in the control specimens without reinforcements. The maximum tensile strengths of reinforced specimens considering real connections such as capital joint and headpiece on a column, increasedby handicraft, especially with domestic red pine species. Dovetail joint is most commonly used in woodworking joinery and traditional horizontal and vertical connections. It is able to be processed much easier to cut by handicraft and machines. However, although it is processed straight forwards, it requires a high degree of accuracy to ensure a snug fit. Also, tenons and mortises must fit together with no gap between them so that the joint interlocks tightly. A few scientific studies on the dovetail joints have been conducted so far. For the effective applications of traditional joints and domestic plantation wood species, dovetail joints were assembled by larch glulam members processed by machine pre-cut. To identify the tensile properties of through dovetail joints, larch glulam with 150 150mm in cross section were prepared. Furthermore, various geometric parameters of dovetai joints such as width, length, and tenon angle, were surveyed. The ends in the mortise was cracked mainly at a low strength level in the control specimens without reinforcements. The maximum tensile strengths of reinforced specimens considering real connections such as capital joint and headpiece on a column, increased by two times with shear failures on the tenon than the control specimens. The maximum tensile strength was obtained in the specimen of 25 degrees, and no difference was observed in the changes of neck widths.