• Journal of the Korean Wood Science and Technology
• /
• 제23권4호
• /
• pp.46-53
• /
• 1995

The anatomy of Korean diffuse-porous woods, 36 families, 75 genera, 145 species, 215 specimens was described and analyzed. Sixteen wood anatomical characters, habit and phenology factors were determined by simple correlation and principal component analysis. Strong positive correlations were found between vessel element length and fiber length, ray width and ray height, simple pits of fiber wall and paratracheal parenchyma distribution. The results of principal component analysis (PCA) disclose the primitive characteristics and the direction of xylem evolution of Korean diffuse-porous woods. The xylem evolution scenario for Korean dicotyledonous woods is considered to be developed in the direction of decreasing trends of vessel frequency, vessel element length, and length/diameter(L/D) ratio of vessel element but increasing trends of vessel diameter, fiber length/vessel element length(F/V) ratio, libriform wood fibers, simple perforation, and homogeneous ray composition. Increase of vessel diameter and decrease of vessel frequency seem to be related to the improvement of conductive efficiency, and increase of the vessel element length and occurrence of scalariform perforation in vessel element may be related to enhanced of conductive safety. Also the libriform wood fibers and ray features appear to have relationship with mechanical support and nutrient metabolism, respectively.

• 한국산업융합학회 논문집
• /
• 제9권4호
• /
• pp.247-253
• /
• 2006

Power consumption for double-stage paddle impeller in spherical and cylindrical agitated vessel was measured over a wide range of Reynolds number from laminar to turbulent flow regions. The power correlation was obtained which was applied to both spherical and cylindrical vessel, when the apparent diameter of the spherical vessel was equal to the diameter of the cylindrical vessel which had a height equal to its diameter and had the same volume as the spherical vessel. The power consumption for the double-stage impeller was dependent upon the distance of among the impeller in the agitated vessels, as follows: $$f/2={\frac{C_L}{Re_G}}+{\frac{Ct}{2}}({\frac{C_tr}{Re_g}}+Re_g)^{-m}$$

• 한국가구학회지
• /
• 제21권1호
• /
• pp.54-61
• /
• 2010

This study was carried out to identify the differences of some macro and microanatomical features between Eunsasi poplar (Populus tomentiglandulosa T. Lee) and Konara oak (Quercus serrata Thunb.). Anatomical features such as vessel and fiber diameter, cross sectional area of ray parenchyma and endwall pit aperture diameter in ray parenchyma were compared. Differences of anatomical features between two species were found statistically significant. Earlywood vessel diameter in poplar and oak increased from pith to bark while it was found almost stable in latewood. Fiber diameter in poplar was higher than oak fiber. Ray area and the pit aperture diameter in endwall of ray parenchyma were found higher in oak than those in poplar.

• 한국안전학회지
• /
• 제11권2호
• /
• pp.79-88
• /
• 1996

A hypothetical accident in the containment vessel of liquid metal reactor could cause a pressure, temperature rise, and a strong aerosol release. The computer codes relating to the modelization of these accident make it necessary to use various input parameter, among which is the dynamic shape factor of aerosols produced. Combustion experiments of sodium spray fire carried out in a closed vessel, which was vertical cylinder made of 1.2m in diameter and 1.8m hight with a volume of 1.7$m^3$. The results of theoretical analysis presented here was compared to data obtained from experiments. The experimental results were summarized as follows. 1) The aerodynamic diameter and geometric diameter of aerosols are decreasing with increasing of injection pressure and injection temperature of sodium 2) The dynamic shape factor of aerosol is proportional to the aerodynamic diameter for a given particle. 3) The correspondence between the aerodynamic diameter and geometric diameter can be as $D_{ae}=0.70 D_{ge}$. 4) Peak pressure rose with increase in pressure and temperature of injection sodium, being more sensitive to the injection pressure than the injection temperature.

• Journal of the Korean Wood Science and Technology
• /
• 제24권1호
• /
• pp.1-10
• /
• 1996

The frequency distribution diagrams of Korean diffuse-porous woods, 36 families, 75 genera, 145 species, 215 specimens in relation to habit and phenology were analyzed. As the habit character changes from shrub to tree, such quantitative features as vessel frequency, percentage of solitary vessels, length/diameter(L/D) ratio of vessel element decreased but tangential vessel diameter, fiber length/vessel element length(F/V) ratio increased. Qualitative features such as helical vessel wall thickening, diffuse distribution of longitudinal parenchyma, heterogeneous ray composition decreased, while alternate intervessel pits, libriform wood fiber, simple perforations increase. As the phenology character changes from evergreen to deciduous species, such quantitative features as percentage of solitary vessels, vessel element length and L/D ratio decreased but tangential vessel diameter, F/V ratio increased. Diffuse distribution of longitudinal parenchyma, heterogeneous ray composition, and crystals in qualitative features decreased, while alternate intervessel pits, libriform wood fiber, simple perforation of vessel element, ray width and ray height increased.

• Journal of Plant Biology
• /
• 제31권3호
• /
• pp.169-185
• /
• 1988

Vessel elements in lateral root, tap root, transition region, stem and mid vein of 1-year old, 3-year old and 5-year old ginseng (Panax ginseng C.A. Meyer) are studied with light microscope to clarify the distribution and differentiation of several kinds of vessel elements. Vessel elements are classified into five types such as ring vessel, spiral vessel, scalariform vessel, reticulate vessel and pitted vessel according to the secondary thickenings of cell wall. All of the five types are not observed in each organ, but diverse kinds of vessels are present in stem and mid vein compared with the underground organs such as tap root and lateral root. The length of vessel elements is longest (680$\mu$m) in stem and shortest (143$\mu$m) in tap root. The diameter of vessel elements is 19.0$\mu$m in tap root and the angle of perforation plate comes under 22$^{\circ}$-60$^{\circ}$. The degree of differentiation of vessel elements according to the length, diameter and angle of perforation plate of vessel elements is highest in tap root regardless of the age of ginseng. Three types of perforation plate such as scalariform, intermediate type of simple and scalariform, and simple perforation plate are observed. The vascular tracheids are characteristically observed in mid vein of 1-year old ginseng, and in transition region of 3 and 5-year old ginseng.

• 대한의용생체공학회:의공학회지
• /
• 제16권3호
• /
• pp.289-300
• /
• 1995

지금까지는 혈관의 중심선을 구해서 혈관의 직경을 측정해 왔다. 혈관의 중심선을 구하는 방법은 2가지가 보고되어 있는데 그중 하나는 maunal로 중심선을 찾는 observer-defined 방법이다. 이 방법을 사용자에 따라 변화할 가능성이 잠재한다, 또 다른 방법은 자동으로 혈관의 중심을 찾아내는 것인데 대단히 복잡하다. 이 논문에서, 중심선을 찾지 않고 방향코드와 위치정보를 이용하여 직경을 구하는 새로운 방법을 제안한다. 이 방법은 경계선과 방향코드를 동시에 검출하기 때문에 절차가 간단해지고 처리속도도 빨라진다. 중앙선을 이용하여 자동으로 혈관직경을 구하는 방법과 비교해보면, 가지가 있거나 장애가 있는 혈관 이미지에 있어서 정확도가 개선된다. 또한 방향 코드는 3비트로 코드화되기 때문에 혈관정보를 압축 저장하는데 용이하다. 이 방법은 실험을 통하여 유용성이 있음을 확인하였다.

• 한국화재소방학회논문지
• /
• 제18권3호
• /
• pp.39-44
• /
• 2004

Pool화재의 화염 거동을 알아보기 위하여 산업에서 많이 사용되는 가연성 액체인 아세톤 메탄을 헥산 그리고 헵탄을 직경 50mrn에서 400nun까지의 용기 내에 넣고 연소실험을 하였다. 용기의 재질은 스테인리스와 구리를 사용하였다. 연소시간과 용기 벽면의 온도 및 열유속 등을 측정하였으며 연소 시 화염의 거동은 비디오카메라를 이용하여 촬영하였다. 실험을 통해서 연소속도와 화염의 높이는 용기 직경의 증가와 함께 증가하였으며 화염의 와류 생성 주기는 용기 직경에 반비례하였다. 또한 pool화재의 특성은 액체연료의 물리 화학적 성질과 용기의 재질에 의해서도 영향을 받는 것을 알 수 있었다.

• 한국가구학회지
• /
• 제17권3호
• /
• pp.29-36
• /
• 2006

Juvenile and matured wood of Populus tomentiglandulosa species of Salicaceae native grown in Korea was observed by FE-SEM and optical microscope. Species is characterized by mostly diffuse-porous, simple perforation plates, polygonal alternate non-vestured intervessel pit, medium length of vessel elements and fibres, non-septate very thin walled libriform fibres and exclusively uniseriate procumbent rays. Axial parenchyma was absent or extremely rare. Vessel and fibre length were longer in both matured and juvenile latewood than those of earlywood. Ray cell lumen diameter, ray length, number and diameter of endwall pit in ray cell, endwall pit, number and diameter of pit in lateral wall of one ray parenchyma cell, vessel ray pit number and diameter vary from juvenile early and latewood to matured wood.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2004년도 추계학술발표대회 논문집
• /
• pp.224-227
• /
• 2004

A computer program for composite pressure vtlssel design is developed. In-puts are : material-property(young's modulus, shear modulus, tensile strength, poisson's ratio, density), operating pressure, burst pressure, liner thickness, boss diameter, boss weight and number of helical angles. Out-puts are; thickness of each layer, weight of the vessel, dimension of the vessel, inner volume, dome-shape and helical winding angle. Also filament winding angles can be selected various kinds of utilizing virtual boss diameter.