• 한국환경과학회지
• /
• 제22권10호
• /
• pp.1345-1351
• /
• 2013

Leaf characteristics of two representative deciduous-tree species in Korean peninsula were compared to assess directional ridge effect on leaf traits of both species. Leaf mass per unit area (LMA) of Rhododendron schilippenbachii in south-facing ridge slope was significantly higher than that in north-facing ridge slope, while Quercus mongolica did not change LMA. Leaf mass of Q. mongolica was increased depending on leaf size irrespective of slope. However, leaf mass of R. schilippenbachii changed differently in responding to expansion of leaf area between both slopes resulting from retardation of leaf expansion in south-facing slope. R. schilippenbachii showed higher leaf nitrogen concentration per unit area (LNCA) in south-facing slope than that in north-facing slope, while Q. mongolica indicated no difference in LNCA between southand north-facing slopes. However, both species revealed no significant difference in leaf nitrogen concentration per unit mass (LNCM) between south- and north-facing slopes. LNCA of Q. mongolica was about two times higher than that of R. schilippenbachii. These results indicate that there is a difference in leaf characteristics including leaf thickness and nitrogen allocation between Q. mongolica and R. schilippenbachii, suggesting the difference of plasticity.

• Tribology and Lubricants
• /
• 제33권6호
• /
• pp.251-255
• /
• 2017

In this study, we aimed to clarify the wettability and anisotropic flow characteristics of rice leaves as a basic study for engineering applications of anisotropic flow characteristics of rice leaf surface. To investigate the surface structure of rice leaf, the micro grooves and asperities of rice leaves were analyzed and quantified by scanning electron microscope, Confocal laser scanning microscopy, and stylus profilometer. The analysis of the structure of rice leaf surface confirmed that asymmetrical cone - like protrusions in leaf veins were inclined toward the leaf tip. The static contact angle test showed that the contact angle at the midline vein or leaf vein location where the micropapilla is concentrated is about $20^{\circ}$ higher than the leaf blade position. The contact angles of fresh and dried rice leave were also compared. The dried rice leaves showed a contact angle of about $5^{\circ}$ to $15^{\circ}$ higher than that of fresh leaves, suggesting that the volume of the protrusions decreased as the water was removed, thus reducing the contact area with the droplet. In the contact angle history test the hysteresis in the leaf tip direction was found to be much lower than that in the leaf petiole direction. This results can be explained that asymmetrical cone - like protrusions had a significant effect on the droplet flow characteristics through contact angle hysteresis experiment.

• 한국산림과학회지
• /
• 제68권1호
• /
• pp.46-51
• /
• 1985

우리나라에서 유용죽종(有用竹種)으로 취급(取扱)되고 있는 왕대의 몇가지 엽형질(葉形質)에 대(對)하여 지역(地域)과 죽림분간(竹林分間)에 따른 변이정도(變異程度)를 구명(究明)하여 다음과 같은 결과(結果)를 얻었다. 엽형질(葉形質)에 있어서 이리지역(裡里地域)의 변이계수(變異係數)가 다른 지역(地域)에 비(比)하여 크게 나타났으며 죽림분간(竹林分間)의 변이계수(變異係數)에 있어서도 큰 차이(差異)를 나타냈다. 또한 이리지역(裡里地域)을 제외(除外)한 다른 지역간(地或間)에 있어서 엽형질(葉形質)의 평균치(平均値)는 차이(差異)가 없었으나 지역내(地域內)의 죽림분간(竹林分間)에 있어서는 대부분이 유의차(有意差)가 인정(認定)되었다. 엽폭(葉幅)/엽신장(葉身長)의 형상비(形狀比) 출현율(出現率)에 있어서 경주(慶州), 울산지역(蔚山地域)은 다른 지역(地域)에 비(比)하여 다소(多少) 분리(分離)되는 경향(傾向)이었다. 이상(以上)의 결과(結果)에서 왕대의 엽형질(葉形質)은 지역간(地域間)보다 지역내(地域內)의 죽림분간(竹林分間)에 따라 변이폭(變異幅)이 크게 나타나고 있음을 알 수 있었다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 추계학술대회 논문집
• /
• pp.620-623
• /
• 2000

The leaf spring is generally used effectively in load supporting because it has tension-diffused function in comparison with other springs. Nowadays the leaf spring is used widely in the suspensions of automobile and trains. The stiffness and the damping characteristics of the leaf spring being essential for the performance of vehicles, the exact evaluation is required. Various approximate formula are normally used for the leaf spring design. however, accuracy and trust are decreased because the contact and frictional characteristics between leaf plates are generally neglected. In this paper, nonlinear stiffness matrix of the leaf spring is solved by contact-element applying FEM for considering the contact and frictional characteristics between leaf plates. The results of proposed FE model are compared with test data.

• 한국식생활문화학회지
• /
• 제23권5호
• /
• pp.639-645
• /
• 2008

The objective of this study was to assess the quality characteristics of morning-rolls containing various levels (0, 4, 8, and 12%) of bamboo leaf powder. The results demonstrated that morning-roll volume decreased with increasing amounts of bamboo leaf powder, and as the bamboo leaf powder content increased, the Hunter's color 'L', 'a' and 'b' values were significantly reduced (p<0.05). For the amylogram characteristics, the addition of bamboo leaf powder to the flour reduced peak viscosity, holding strength, final viscosity, and setback. The results of the sensory evaluation demonstrated that control (0%) and 8% addition of bamboo leaf powder had the best scores in taste, color, flavor, texture, appearance, softness, wetness, residual mouth feel, and overall acceptability. Thus, it appears that by using 8% additions of bamboo leaf powder, the functionality, nutritional composition, taste, color, and flavor of morning-rolls containing bamboo leaf powder can be developed. This result will support the development of better quality bamboo-leaf morning-rolls.

• 한국식품조리과학회지
• /
• 제25권1호
• /
• pp.55-61
• /
• 2009

This study examined the effects of added amounts of lotus leaf powder on the physical and sensory properties of Jook. As the level of lotus leaf powder in samples increased, L-values and a-values decreased and b-values increased. In addition, the Jook had higher viscosity and lower spreadability values as the amount of lotus leaf powder increased. Sensory characteristics such as color intensity, viscosity, astringency, and nutty taste increased significantly with the addition of lotus leaf powder. And the results of the consumer acceptability test showed that the Jook containing $2%{\sim}3%$ lotus leaf powder had the highest score. In conclusion, to enhance the quality of Jook, a 2% addition of lotus leaf powder would be the most beneficial.

• 한국식생활문화학회지
• /
• 제32권6호
• /
• pp.558-565
• /
• 2017

This study examined the quality characteristics of cookies prepared with mulberry leaf powder (0, 1, 3, 5, and 7%) substituted for flour. The pH of the cookie dough decreased significantly in response to the addition of all levels of mulberry leaf powder. The spread factor of the cookies also increased significantly with increasing mulberry leaf powder content added to the cookies recipe. In addition, the Hunter's color L and a values decreased significantly with increasing mulberry leaf powder content, whereas the b value increased. According to hardness measurements, the substitution of 1~7% mulberry leaf powder resulted in increased hardness compared to the control. Moreover, the DPPH free radical scavenging activity of the cookies was increased significantly (p<0.05) with increasing levels of mulberry leaf powder. The sensory evaluation revealed cookies containing 3% to have the highest scores.

• 동아시아식생활학회지
• /
• 제21권3호
• /
• pp.367-374
• /
• 2011

The purpose of this study was to determine the optimum condition for producing tea leaf Jeung-pyun that does not contain added parched tea leafs (0, 0.5, 1, 1.5, and 2%) while producing Jeung-pyun that has a variety of functional ingredients and to investigate the possibility of making practical application of tea leafs. Moisture contents were 56 ~66% and there were no significant differences among the samples. The pH of Jeung-pyun samples was 5.65~5.74. The L-value decreased as the amount of added tea leaf increased, and the a-value was low in the group made with added tea leafs. The b-value was high in the 1% added group and had a tendency to increase vs the control group as amount of added tea leaf increased. In the groups with added tea leaf the volume was evaluated as being higher in the order of 1>1.5>2%. The specific volume of the group with added tea leaf was evaluated as being higher in the order of 1>1.5>2%. Sensory characteristics of the group with added tea leaf were evaluated as being high. For characteristics of cell uniformity, rice wine flavor, and sweetness, the control group was evaluated as being high, and for characteristics of color, moistness, and softness the 1% added group was evaluated as high. Astringency was evaluated as being high in the 2% added group. Texture profile analysis was conducted after samples were maintained in an incubator at $20^{\circ}C$ for 0, 1, 3, 5, and 7 days. Characteristics for hardness, gumminess, chewiness tended to increase with longer periods of storage. Characteristics for cohesiveness, springiness tended to decrease as the storage period increased. As determined by this study, addition of 1% tea leaf was the most favorable method for making use of tea leafs the production of Jeung-pyun and a potentiality for the use of tea leafs in food was discorvered.

• 동아시아식생활학회지
• /
• 제15권2호
• /
• pp.188-193
• /
• 2005

As the modern medicine develops, the physique and average life span are increasing. In proportion to that, modern diseases of adult people such as cancer, obesity, arteriosclerosis, cardiac disorder become great social issues. In the meantime, as the development of a new diet brings a new attention, the study is designed to examine the availability of functional food by adding Korean traditional food, soybean Dasik, mulberry leaf. For this study, mulberry leaf was added 0, 5, 10, and $15\%$ respectively to soybean Dasik in proportion to the total weight of soybean power. These are compared with the soybean Dasik itself in relation to the nutritional composition, sensory evaluation, and mechanical characteristics. The results of the research were as follows. Nutritional composition showed that mulberry leaf soybean Dasik increased Na, Ca, K, crude fiber, and ash. As for the result of sensory evaluation of mulberry leaf soybean Dasik, the followings were turned out to be good : color - $10\%$, mulberry leaf smell - $5\%,\;10\%,\;15\%$, bitterness - $5\%,\;10\%$, softness and moistness - $0\%,\;5\%,\;10\%$, and sweetness and overall quality - all the added food group. As the test results of mechanical characteristics, mulberry leaf soybean Dasik showed statistically significant difference only in the hardness, especially high on $5\%,\;10\%,\;and\;15\%$. There were no significant differences in other characteristics. In color, mulberry leaf soybean Dasik showed that L, a and b values decreased as the percentage of addition of mulberry leaf went up. Therefore, the appropriate amount of addition for the production of mulberry leaf soybean Dasik was $5\~10\%$ mulberry leaf in proportion to the weight of soybean power.

• 한국식생활문화학회지
• /
• 제29권4호
• /
• pp.355-363
• /
• 2014

The purpose of this study was to investigate the rheological characteristics of medium wheat flour mixed with bamboo leaf and lotus leaf powders. Rheological properties of the mixed flours were tested based on falling number, color, RVA, farinogram, and rheofermentometer analyses. Falling numbers increased with addition of bamboo leaf and lotus leaf powders. The L values of all mixed flours were less than that of control. The 1% mixed flour sample containing bamboo leaf and lotus leaf powders was not significantly different from 3% mixed flour. The a values of the mixed flour decreased as bamboo and lotus powders increased, whereas b values increased. Addition of bamboo leaf and lotus leaf powders to flour reduced peak viscosity, holding strength, and final viscosity. The set back values of mixed wheat flour containing bamboo leaf powder were lower than those of mixed wheat flour containing lotus leaf powder, suggesting that bamboo leaf powder suppressed retrogradation of flour compared to lotus leaf powder. In the farinogram, the water absorption and consistency of the flours containing bamboo and lotus leaf powders increased, whereas development time and stability decreased. The fermentation time of dough with lotus leaf powder was less than that of dough with bamboo leaf powder.