• Nuclear Engineering and Technology
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• 제30권4호
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• pp.287-297
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• 1998

The elastic stiffness formula of leaf type holddown spring(HDS) assembly is verified by comparing the values of elastic stiffness with the characteristic test results of the HDS's specimens. The comparisons show that the derived elastic stiffness formula is useful in reliably estimating the elastic stiffness of leaf type HDS assembly. The elastic stiffness sensitivity of leaf type HDS assembly is analyzed using the formula and its gradient vectors obtained from the mid-point formula. As a result of sensitivity analysis, the elastic stiffness sensitivity with respect to each design variable is quantified and design variables of large sensitivity are identified. Among the design variables, leaf thickness is identified as the most sensitive design variable to the elastic stiffness of leaf type HDS assembly. In addition, the elastic stiffness sensitivity, with respect to design variable, is in power-law type correlation to the base thickness of the leaf.

• Journal of Ecology and Environment
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• 제31권3호
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• pp.193-200
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• 2008

We obtained quantitative information on leaf unfolding and leaf shedding by observing 45 species of cool temperate deciduous trees in an arboretum over 5 growing seasons. These trees were in leaf (the foliage period) for 207 days on average after 1 April; 50% of leaves had been shed by 192 days after 1 April. Duration from the start of leaf unfolding to 50% leaf shedding was 157 days on average. Leaf unfolding began 35 days on average after 1 April. For leaf unfolding to begin, a$ 51^{\circ}C{\cdot}day$ of cumulated daily mean air temperature above $5^{\circ}C$ from 1 January (modified Kira's warmth index) was needed. Fifty-nine days elapsed between initiation and the final stage of leaf unfolding. The period of net photosynthetic assimilation was 157 days. The species with succeeding- type leaf unfolding associated with the anemochore seed type dominated the early stage of succession, while the species with flush-type leaf unfolding tended to dominate the late stage of succession. Few species were found in regions where late frosts occur after the day when the cumulative temperature for leaf unfolding is achieved. Biological characteristics include time of leaf unfolding, which affects the life history of each species, so that each species occupies its own niche in the stand. We conclude that that leaf phenology, such as timing of leaf unfolding and leaf shedding, is one of the components of each species' ecological characteristics.

• Korean Journal of Weed Science
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• 제30권4호
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• pp.380-389
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• 2010

Transgenic herbicide-resistant sweet potato plants [Ipomoea batatas (L.) Lam.] produced through a biolistic transformation were used in this study. The objective of this research was to find out a rapid and reliable assay method for confirming glufosinate-ammonium resistance. The techniques tested include whole-plant bioassay, one leaf bioassay, and leaf disk bioassay. Parameters investigated in this study were leaf injury and ammonium accumulation at 1 and 5 days after treatment of glufosinate-ammonium. In the leaf disk bioassay, leaf injury of the transgenic line 7171 was 1.9-fold less affected by glufosinate-ammonium than the wild type. The leaf injury of 7171 in one leaf and whole-plant bioassays was 59- and 92-fold less affected by glufosinate-ammonium, respectively, compared with that of the wild type. Leaf disk, one leaf, and whole-plant bioassays showed that ammonium accumulation of the 7171 was 2 to 20-, 4 to 43-, and 6 to 115-fold less affected by 0.5-5 mM glufosinate-ammonium than that of the wild type. All three bioassays successfully distinguished the resistance from the transgenic lines, but one leaf bioassay is the simplest and quickest. Leaf injury and ammonium accumulation were the same in leaves 1, 3, 5, 7, and 10 of 3 mM glufosinate-ammonium treated plants or nontreated plants. The one leaf bioassay was chosen as the standard procedure for future confirmation of resistance in transgenic sweet potato because it is a rapid and reliable assay.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제21권8호
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• pp.1276-1290
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• 1997

The previous elastic stiffness formulas of leaf type holddown spring assemblies(HDSs) have been corrected and extended to be able to consider the point of taper runout for the TT-HDS and all the strain energies for both the TT-HDS and the TW-HDS based on Euler beam theory and Castigliano'stheorem. The elastic stiffness sensitivity of the leaf type holddown spring assemblies was analyzed using the derived elastic stiffness formulas and their gradient vectors obtained from the mid-point formula. As a result of the sensitivity analysis, the elastic stiffness sensitivity at each design variable is quantified and design variables having remarkable sensitivity are identified. Among the design variables, leaf thickness is identified as that of having the most remarkable sensitivity of the elastic stiffness. In addition, it was found that the sensitivity of the leaf type HDS's elastic stiffness is exponentially correlated to the leaf thickness.

• KOREAN JOURNAL OF CROP SCIENCE
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• 제5권1호
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• pp.65-68
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• 1969

Studies wre made to investigate the relationships obetween measurable characters of leaf tobacco such as stem length, stem daimeter, number of leaves, leaf length, leaf thickness, leaf area of biggest leaf and the dry Iield. The results are summarized as follows; n the flue cured yellow tobacco; leaf width and leaf area of biggest leaf were significantly correlated to the yield. In the light air cure type of tobacco; stem diamer, leaf width and leaf area of biggest leaf were significantly correlated to the yield. In the dark air cured type of tobacco; stem diameter, number of leaves, leaf length, leaf width, and leaf area of biggest leaf were significantly correlated to the yield. It would be noticiable that the yield was significantly correlated to the leaf width which is easily measurable in the field, and negatively correlated to the leaf thickness though not significantly.

• Journal of Biosystems Engineering
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• 제22권1호
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• pp.30-40
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• 1997

A computer vision system was built to automatically grade the leaf tobacco. A color image processing algorithm was developed to extract shape, color and texture features. An improved back propagation algorithm in an artificial neural network was applied to grade the Burley type dried leaf tobacco. The success rate of grading in three-grade classification(1, 3, 5) was higher than the rate of grading in six-grade classification(1, 2, 3, 4, 5, off), on the average success rate of both the twenty-five local pixel-set and the sixteen local pixel-set. And, the average grading success rate using both shape and color features was higher than the rate using shape, color and texture features. Thus, the texture feature obtained by the spatial gray level dependence method was found not to be important in grading leaf tobacco. Grading according to the shape, color and texture features obtained by machine vision system seemed to be inadequate for replacing manual grading of Burely type dried leaf tobacco.

• Asian Journal of Turfgrass Science
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• 제24권2호
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• pp.88-96
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• 2010

Zoysiagrass, especially Jungji implicating medium-leaf type zoysiagrass has been widely used in South Korea recently. This study was carried out to classify 36 selected medium-leaf type zoysiagrass accessions compared to 5 basic zoysiagrass species using RAPDs. Morphological characteristics such as leaf width, leaf angle, leaf sheath length, existance of trichomes and stolon color were measured as useful characteristics for identification of species in Zoysia genus. Nineteen RAPD markers were identified using 8 selected random primers. The dissimilarity coefficient of variants ranged from 0 to 0.736. Three zoysiagrass groups were clustered by dissimilarity coefficient analysis. Group 1 consisted of Z. japonica and some US varieties including 'Zenith' and 'Meyer'. Group 2 consisted of Z. sinica, Z. macrostachya and Korean commercial varieties such as 'Anyang', 'Samdeock', and 'Pyeongdong' medium-leaf type grasses. Group 3 was genetically distinct from Group 1 and Group 2, and included Z. matrella and Z. tenuifolia. 'Anyang', 'Samdeock', and 'Pyeongdong' medium-leaf type zoysiagrasses showed very close genetic relationship with Z. sinica and Z. macrostachya.

• Journal of People, Plants, and Environment
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• 제22권6호
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• pp.551-561
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• 2019

This study was conducted to find out differences in the removal efficiency of particulate matter (PM) depending on the type of plants and the morphological characteristics of leaves. A total of 12 plants were used, with three plants selected for each type of leaves (big leaf, small leaf, compound leaf, needle leaf). We measured the removed amount of PM10 and PM2.5, the structure of the abaxial leaf surface, and the weight of the wax layer of each plant. Plants with the high removal efficiency of PM included Pachira aquatica Aubl., Ardisia crenata, and Dieffenbachia 'Marianne', and plants with the low removal efficiency included Nandina domestica Thunb, Schefflera arboricola, and Quercus dentata. The abaxial leaf surface having a high removal efficiency of PM had many large wrinkles, and the abaxial leaf surface having a medium removal efficiency was flat and smooth. On the other hand, there were many fine hairs on the abaxial leaf surface with a low removal efficiency. According to the plant leaf type, the PM10 removal efficiency of plants with needle leaves was about three times higher than that of other plants. In particular, the wax layer of conifers weighed 6-24 times higher than those of other plants. The stomata of conifers were evenly distributed on the adaxial and abaxial leaf surfaces; however, the stomata of Sciadopitys verticillata appeared in the form of papillae unlike general stomata. Therefore, the removal efficiency of PM varied depending on the macro-, and micro-morphological characteristics of plant leaves such as the structure of the abaxial leaf surface, and the weight of the wax layer. Based on this research, selecting plants that are effective in reducing PM in consideration of the plant type and leaf characteristics will improve indoor air quality and decrease exposure of PM to human body.

• Preventive Nutrition and Food Science
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• 제21권4호
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• pp.378-383
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• 2016

Diabetic kidney disease is the most common and severe chronic complication of diabetes. The leaf of Diospyros kaki Thumb (persimmon) has been commonly used for herbal tea and medicinal purposes to treat a variety of conditions, including hypertension and atherosclerosis. However, the effect of persimmon leaf on kidney failure has not been investigated. This study aimed to examine the role of persimmon leaf in protecting the diabetes-associated kidney damage in a mouse model of type 2 diabetes. Mice were fed either a normal chow diet with or without powered persimmon leaf (5%, w/w) for 5 weeks. In addition to kidney morphology and blood markers of kidney function, we assessed levels of oxidative stress markers as well as antioxidant enzymes activities and mRNA expression in the kidney. Supplementation of the diet with powered persimmon leaf not only decreased the concentration of blood urea nitrogen in the plasma but also improved glomerular hypertrophy. Furthermore, the persimmon leaf significantly decreased the levels of hydrogen peroxide and lipid peroxide in the kidney. The activities of superoxide dismutase, catalase, and glutathione peroxidase and the mRNA expression of their respective genes were also increased in the kidney of persimmon leaf-supplemented db/db mice. Taken together, these results suggest that supplementation with the persimmon leaf may have protective effects against type 2 diabetes-induced kidney dysfunction and oxidative stress.

• Journal of the Korean Society of Tobacco Science
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• 제18권2호
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• pp.107-112
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• 1996

The occurrence and chemical properties of grey tobacco leaves (Type III) found in 1995 crop of flue-cured tobacco cultivated in paddy field were investigated to compare with those of normal leaves. Cured leaves of NC82 were separated by visual characters into 3 classes of slight, fair and severe symptoms of grey leaf by the percentage of grey parts to whole leaf area. Number of samples classified with discoloring portion was the order of greyish brown > reddish brown > greyish yellow, respectively. Grey leaves of this type were mostly found among the leaves harvested from upper stalk position, and it was estimated that growth rate of upper leaves also influenced on the occurrence of grey leaves. Grey leaves showed remarkably lower b* and L* values than those of normal leaves, while a* value was mostly higher in grey leaves. These tendencies in chromatic aberration showed more remarkable difference in the degree of grey symptoms. Chemical analyses of grey leaf samples indicated that they contained less total nitrogen and nicotine, and more total sugar and starch than those of normal leaves. In chemical traits, these tendencies were accordance with the degree of grey symptoms, and within the same leaf, grey parts were decreased in total nitrogen and ether extract content compared with those of normal parts, but there was no difference in nicotine and Cl contents. Key words : grey leaf tobacco (type III), grey symptom, color, chemical properties.