• 한국산림과학회지
• /
• 제96권2호
• /
• pp.197-202
• /
• 2007

This study is conducted to investigate the factors affecting lumber conversion rate of sawmill industry in South Korea. Data were obtained from the survey of 38 sawmills in all geographic regions of South Korea. The variables examined in this study were region, softwood/hardwood log, domestic/imported/both log, the number of power-driven carriages (PDC) installed, the year when and country where PDCs was manufactured, the horse power of PDC, the number of labors required to operate each PDC, the sawing capacity of mill (mill size), and the types of major product and by-products. The lumber recovery factor (LRF) of sawmills were significantly influenced by the origin of logs, level of PDC automation, sawmill size, and size of logs (measured in diameter and length) while not by the location of the mill, types of major product and by-product, log species, and characteristics of PDC. Although these results provide useful information for understanding the technological characteristics of the Korean sawmill industry, further investigation with larger sample is necessary to reveal the more reliable characteristics of sawmill industry in South Korea.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 춘계학술대회논문집
• /
• pp.495-498
• /
• 2002

Recently, the advent of electro-active papers (EAPap) actuators has been reported. In this paper, the possibility of the actuators is demonstrated. EAPap is a paper that produces large displacement with small force under an electrical excitation. EAPap is made with a chemically treated paper by constructing thin electrodes on both sides of the paper. When electrical voltage is applied on the electrodes the EAPap produces bending displacement. To improve the bending performance of EAPap, different paper fibers-softwood, hardwood, bacteria cellulose, cellophane, carbon mixture paper, electrolyte containing paper and Korean traditional paper, in conjunction with additive chemicals were tested. Two attempts were made to construct the electrodes: the direct use of aluminum foil and the gold sputtering technique. It was found that a cellophane paper exhibits a remarkable bending performance. When 2MV/m of excitation voltage was applied on the paper actuator, more than 3mm of tip displacement was observed out of the 30 mm long paper beam. This is quite low excitation voltage compared to that of other EAPs. The actuation principle of electro-active paper (EAPap) and possible applications are addressed.

• Journal of the Korean Wood Science and Technology
• /
• 제19권4호
• /
• pp.7-17
• /
• 1991

The feasibility of treating three softwood(Japanese larch pitch pine, and Korean pine) thinned logs by double-diffusion treatment processes was investigated. Some posts were incised before immersion, and others were imersed in hot copper sulfate solution. Comparison among species indicated that. in general, pitch pine was most treatable and Japanese larch least treatable. For all three species, almost all treatment schedules gave consistently good penetration and high net retention, but very steep gradient of preservative distribution. As expected, the treatability was increased by the extension of immersion time, increased concentration of treating solution, incising. and heating of the first solution. Of the variables tested, it appears that heating of the first solution is the most important. From the data in this paper, it may be concluded that, if the first solution is not heated, the best schedule is #3. If the first solution is healed. it appears the best schedules are #10 or #11. Since heating of the first solution improves the treatability. schedules # 10 or :#11 are recommended if the cost of heating might be justified. The data presented in this paper indicate that double-diffusion treatment processes seem to offer a promise as a comparatively effective and easy-operating method of treating thinned logs for the small-scale production of treated stock.

• Journal of the Korean Wood Science and Technology
• /
• 제10권3호
• /
• pp.190-193
• /
• 1982

Conclusion: The results of this study are encouraging for the development of a set of interpretable diagnostic criteria for a reasonably reliable identification of some species. The present study has been limited in the characteristics studied and was made on relatively poor photography. Further study on high quality photography, over wider areas and including such additional characteristics as crown texture and shadow intensity should prove useful. A preliminary examination has been made of some photo-image characteristics of a number of important tree species on large scale (1:9,000) contact prints of panchromatic mm. The characteristics studied were crown image tone, and shape. Image tone was estimated against a standard grey-scale and shows within-species consistency and a range between species. Crown shapes were subjectively assessed but there appears to be a within-species consistency and interpretable between-species differences. The results of this trial suggest that it should be practicable to make a number of important species distinctions by photo-interpretation with a useful degree of reliability. Other characteristics beside those studied might be usefully examined. Photography: Hand-printed glossy contact prints of vertical 1:9,000 scale panchromatic photography of Kwangnung Experimental Forest flown May 1964. The filter used is unknown (probably minus-blue). The camera is unknown but was probably a military type K-17 or K-22 with 6"(apostfophy) lens. The photography shows notably poor resolution. Species: 143 individual trees ranging through 11 species (7 softwood, 4 hardwood) were included in the study. A range of size classes were included for each species.

• 펄프종이기술
• /
• 제43권5호
• /
• pp.60-67
• /
• 2011

Hemicelluloses pre-extracted from Korean mixed wood chip were investigated as a wet-end additive. Hemicelluloses dissolved in hot water and alkali solution were isolated by ethyl alcohol precipitation from pre-extractives. They showed molecular weight of 9,000 ~ 27,000 g/mol as revealed by size exclusion chromatography. The reduction of molecular weight through hot water extraction was caused by autohydrolysis. Chemical composition of the hemicelluloses were analyzed with high-performance liquid chromatography and UV-Vis spectroscopy. As the surface charge of isolated hemicelluloses were negative, the adsorption of hemicelluloses onto softwood unbleached kraft pulp fiber was promoted by poly-DADMAC. The physical properties of handsheets increased as the molecular weight of hemicellulose increased. On the other hands, the optical property decreased with hemicellulose adsorption.

• Journal of the Korean Wood Science and Technology
• /
• 제17권2호
• /
• pp.26-33
• /
• 1989

The acoustic absorption coefficient and acoustic impedance of 5 species of softwood(sonamoo, sam namoo, gusang namoo, hwaback, sitka spruce) and 5 species of hardwood (Mulgusul namoo, Italian popular, white meranti, red meranti, kalantas) were measured by the standing wave method. which is simple in the setup and gives more accurate result than does any other measuring method. The dependence of the absorption coefficient and complex acoustic impedance on the wood sections. thickness of the sample itself and the back air gap was investigated experimentally in the frequency range from 200Hz to 1800Hz, and the result are as follows: 1. The acoustic absorption coefficient of wood sections was higher on the cross section than radial and tangential sections. 2) The acoustic absorption coefficient were higher in the frequency range from 400Hz to 600Hz, but decreased in the frequency above 600Hz. 3. The genenal tendency of the variation of the normal acoustic impedance was increased according to the frequency. 4. The acoustic absortion coefficient was increased in the to 7mm-thick sample and decreased in 9mm-thick sample. 5. The higher acoustic absorption coefficient was shown in the case with the backing an gap than in the case without the gap.

• 한국약용작물학회지
• /
• 제28권5호
• /
• pp.354-359
• /
• 2020

Background: The recent, decline in Black-berry Magnolia Vine (Schisandra repanda; BMV) native to Jeju Island, Korea, has raised concerns about the causes of this decline. We investigated the native environment of S. repanda and evaluated its propagation through cuttings to provide preliminary data for its restoration in Jeju Island. Methods and Results: The native environment of the BMV in the Hallasan National Park was surveyed and the climatic variables (temperature and humidity) were analyzed. The effects of the sex of the donor plant (male/female) type of cutting (softwood/hardwood), and treatment with a plant growth regulator (indole-3-butylic acid/rootone) on the rooting of BMV were investigated. Additinallly, the rooting rate, root count, and root length, as well as temperature and humidity were measured in the vinyl moist chambers. BMV was observed in 63 plants distributed from 567 m to 1,364 m above sea level of the Hallasan National Park. In the cutting experiment, the rooting rate was 71.9%, and it was higer in female plants (75.0%) than in male plants (68.8%). Conclusions: The mass propagation of BMV through cuttings valuable for its restoration as without such safeguard measures, the population could face extinction within a few decades.

• 한국연초학회지
• /
• 제32권1호
• /
• pp.12-18
• /
• 2010

The parcel wrapper for cigarettes has been used as the package and media materials for protection and design of product brands. The design of parcel wrapper has been contributed to the delivery of brand image and motivated consumer to purchase the brand. Therefore, the properties of parcel wrapper have been paid attention to highlight the design image, and increasing opacity of media materials has been one of the effective ways to obtain clear design on the paper surface. This study was carried out to improve the opacity of parcel wrapper for cigarettes. The effects of pulp composition and inorganic fillers in the furnish on the optical and mechanical properties were investigated. The use of hardwood in the stock preparation gave the increased opacity of paper than that of softwood. The application of higher refractive indices of fillers was effective to improve opacity. Brightness, tensile strength and stiffness were affected by the retained filler amount on the paper. Increase of filler contents decrease the tensile strength and stiffness due to the lesser bonding ability of fibers.

• Journal of the Korean Wood Science and Technology
• /
• 제15권1호
• /
• pp.22-55
• /
• 1987

본(本) 연구(硏究)는 육안적(肉眼的) 특성(特性)에 의한 목재식별(木材識別)의 속보(續報)로써 앞으로 생산가능(生産可能)한 한국산(韓國産) 단판수종(單板樹種)의 현미경적(顯微鏡的) 목재특성(木材特性)을 조사(調査)하여 합판공업(合板工業)에 필요(必要)한 기초자료(基礎資料)를 제공하기 위하여 실시(實施)하였다. 선정(選定)된 50수종(樹種)의 현미경적(顯微鏡的) 특성(特性)을 조사(調査)하여 수종별(樹種別)로 기재(記載)하였고 이를 바탕으로 하여 침엽수재(針葉樹材) 및 활엽수재별(闊葉樹材別)로 목재식별(木材識別) 검색표(檢索表)를 간략(簡略)하게 보고(報告)하면 다음과 같다.

• Journal of the Korean Wood Science and Technology
• /
• 제23권4호
• /
• pp.18-26
• /
• 1995

국내 합판 산업계는 오랫동안 남양재 활엽수를 주로 사용하여 왔으나, 환경 보존적인 측면에서 열대재의 벌채를 규제하는 등 여러 요인으로 인하여 합판용 원목의 수입이 어려워지고 있다. 이에 대응하기 위하여 합판용 원목을 침엽수재로 대체할 필요가 있으며, 침엽수 합판 제조를 위한 기초 자료를 제공하기 위하여 본 연구를 수행하였다. 공시 수종은 국내에서 조림한 낙엽송과 시베리아산 낙엽송 및 뉴질랜드산 라디에타 소나무였으며, 공시원목으로부터 얻어진 단판의 품질과 이들 단판으로 제조한 합판의 접착력과 휨강도를 조사하였다. 이면 할렬실험에서 시베리아산 낙엽송은 다른 수종에 비해 할렬 밀도가 낮게 나타났다. 단판 품질은 접착력 및 휨강도에 거의 영향을 미치지 않았으나 합판의 휨강도에서는 심재와 변재에 따른 차이가 있음을 알 수 있었다. 이는 합판제조사 심재와 변재를 구별하여 사용할 필요가 있었다. 라디에타 소나무의 변재부로 만든 합판 MOR은 다른 수종에 비해 우수하게 나타났다. 접착력 실험에 있어서는 페놀 접착제를 사용하여 만들어진 합판만이 구조용으로써 사용할 수 있음을 알았다. 목파율은 동일 수종 합판에서는 라디에타 소나무 구성이 가장 높게 나타났으며, 이수종(異樹種) 합판에서는 표판을 국산 낙엽송, 심판을 라디에타 소나무를 사용하여 만든 합판에서 가장 높게 나타났다.