• 대한치과보철학회지
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• 제43권3호
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• pp.314-321
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• 2005

Objectives. The purpose of this study was to compare the shade changes in wet and dry conditions of natural teeth using two different intra-oral colorimeters. Materials and methods. Twenty volunteer subjects have no restorations and fillings in the maxillary central incisors were involved in this clinical study. The color of tooth was measured by two different instruments that were a Shade $Scan^{TM}$ System and a VITA $Easyshade^{(R)}$, Five times consecutive measurements were done for each subject with both instruments. Groups of measurement are an initial wet condition as control, dry in 5 minutes, 15 seconds after re-wetting with saliva, re-wetting after 5minutes and re-wetting after 30 minutes. Using ShadeScan $System^{TM}$, tooth image was captured and converted to the mapping image of Vitapan 3D master. Three main shades were chosen from each subject and calculated the area in Global Lab Image software. Data were analyzed using paired T-Test and Wilcoxon Signed Ranked Test. Using VITA $Easyshade^{(R)}$, color differences($\Delta$E) between measurements were analyzed with one sample T-test. Results. Using ShadeScan $System^{TM}$, there were significant differences between control group and dry(P=.023), dry and re-wetting 15 seconds, 5 minutes, 30 minutes as well(P=.021, P=.017, P=.030) in comparison of primary shade. However, comparing three main shades, there was no significant difference between control and dry(P=.105). Using VITA $Easyshade^{(R)}$, color differences($\Delta$E) between control and dry, dry and re-wetting 30 minutes were statistically different(P=.002, P=.022). Conclusion. Primary shade could be changed in dry and wetting procedure in time, however there was no significant shade changes in overall.

• 구강회복응용과학지
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• 제26권3호
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• pp.265-271
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• 2010

심미적 보철물을 제작하는 데 있어 색조의 선택은 중요한 단계이다. 이러한 색조선택과정은 광원, 표면, 관찰자 의 능력, 주변 배경색상, 관찰각도, 명암적응력 등과 같은 다양한 원인에 의해 좌우된다. 색조를 선택하는 시점에 따라 치아의 건조정도는 달라지게 되므로 본 실험에서는 치아 건조정도가 자연치아의 색조에 미치는 영향에 대해 살펴보고자 하였다. 구강내 색조측정기를 이용하여 구강가글 즉시 측정한 군을 실험군으로 구강가글 10초 후, 1분 후, 5분 후, 30초간 건조 후 색조를 측정하여 ${\Delta}E$값을 비교하였다. 각 실험군사이 ${\Delta}E$값은 유의할 만한 차이를 보였으나 대부분의 경우 구강내에서 시각적으로 구별할 수 없는 정도의 근접치를 보였다. 실험결과 시각적인 방법으로 색조 견본을 이용하는 방법은 건조정도에 따른 색조 차이가 없는 것으로 사료되고 기계를 이용하는 경우 건조정도가 색조 선택에 유의할 만한 영향을 줄 것이라고 사료된다.

• 아시안잔디학회지
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• 제5권1호
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• pp.23-32
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• 1991

The purpose of this study was to determine the vegetative growth of two cool season turfgrasses during summer season in Korea. Ten respective cultivars of Kentucky bluegrass [Poapratensis L.] and perennial ryegrass [Lolium perenne L.] were exposed to unshaded, 30% and 60% shade for 4odays. First mowing height was 7cm, and then clippings were harvested every ten days at the same height. Shading increased the total length of clippings of all cultivars of two turfgrasses, but fresh and dry weight were significantly decreased. The highest shoot length obtained at 30% shade in Kentucky bluegrass and at 60% shade in perennial ryegrass. 'Rugky', 'Sydsport', 'Wabash' and 'Baron' of Kentucky bluegrass and 'Repel', 'Omega II', 'Ovation', 'Linn', 'Bell' and 'Manhattan' of perennial ryegrass showed relatively high tolerance to shade. Especially, in 'Citation II' perennial ryegrass, fresh and dry weight were increased by 30% shade. The number of tillers generally decreased with increasing shade. In 30% shade, 'Midnight' Kentucky bluegrass and 'Omega II' perennial ryegrass were least reduced and 'Baron' Kentucky bluegrass and 'Pennant' perennial ryegrass were most reduced. The cultivars of lower growth habit in full sunlight showed shade tolerance compared to those of higher growth habit.

• Journal of Ecology and Environment
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• 제35권4호
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• pp.343-349
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• 2012

The use of growth medium is often recommended milkweed seedlings to grow and develop after emergence, and it is affected by growth medium and local habitat conditions. The effects of growth medium and partial shade on early growth of milkweed under drought stress (Calotropis procera L.) were studied in a field experiment. A split-split plot experimental design with three replications was carried out in the nursery. The main treatment plot was divided into two levels of shade; (no shading and partial shading). Sub treatment plot1 included growth medium at four levels (G1 = clay [suitable for milkweed growth], G2 = clay + sand, G3 = clay + perlite, G4 = clay + perlite + sand) and sub treatment plot2 included drought (irrigation intervals) at six levels (D1 = 2 [control], D2 = 4, D3 = 6, D4 = 8, D5 = 10, and D6 = 12 days per for three month). The results showed that drought stress significantly decreased emergence percentage, shoot length, shoot dry weight (SDW1), root dry weight (RDW), seedling dry weight (SDW2) and vigor index (VI). The use of growth medium increased all seedling characteristics. The G3 (clay + perlite) growth medium showed the highest performance, especially in terms of emergence percentage and seedling dry weight. Partial shade improved shoot length, shoot dry weight, and vigor index. Our results showed that the best treatment for high-vigor milkweed seedlings under drought stress was G3 (clay + perlite) growth medium and partial shade.

• 원예과학기술지
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• 제32권5호
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• pp.584-589
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• 2014

Jeffersonia dubia is a spring-flowering perennial found in rich forests in Korea and Northern China and has potential as an ornamental or medicinal plant. However, illegal picking and land use change have decreased the number of populations and overall population size of this plant in its natural habitat. Although J. dubia has been reported to be a shade-preferring plant, no study has determined the optimum light intensity for its growth. The objectives of this work were to observe the effects of various shading levels on the physiological responses of J. dubia and to determine the proper shading level for cultivation. Treatments consisted of four shading levels (0%, 50%, 75%, and 95% shade) imposed using black mesh cloth. The number of leaves and dry weight increased with decreased shading. The shoot-to-root ratio increased with increased shading, mainly due to decreased root dry weight under shading. Plants showed low net $CO_2$ assimilation rates and $F_v/F_m$ values combined with low dry matter levels when grown under 0% shade (full sunlight). These results indicate that J. dubia plants experience excessive irradiance without shading, resulting in damage to the photosynthetic apparatus. By contrast, the net photosynthesis rate increased as the shading level increased. $F_v/F_m$, the potential efficiency of PSII, was 0.8 under 95% shade, indicating that J. dubia is well-adapted under heavy shading. However, the low dry matter of plants in the 95% shade treatment indicated that the low light intensity under 95% shade led to a decline in plant growth. Thus, moderate light (50% shading) is recommended for cultivating J. dubia without physiological defects.

• 한국초지조사료학회지
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• 제11권3호
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• pp.175-181
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• 1991

The purpose of this experiment was to evaluate the effects of shade and levels of N fertilization on the dry matter yield and chemical compositions of orchardgrass grown under floor of chestnut tree. Shading conditions consist of $S_0$, (full light), $S_1$, (about 6OC4 shade) and $S_2$, (about 70% shade). And, nitrogen fertilizer was applied at 3 levels, O($N_0$), 12($N_1$), and 30($N_2$) kg per 10a, respectively. The results are may be summarized as follows: 1. Maximum total dry matter yield of $S_0$, was obtained about 1.28 ton/lOa at $N_2$, level. But, total dry matter yields of N levels in $S_1$, and $S_2$, were decreased about 42-45% compared with $S_0$. 2. The response of the dry matter yield to N fertilization were differences between shading and levels of N. Thus, the dry matter yield of $S_1$, increased almost linear up to about 30 kg/l0a level, while the dry matter yield of S, was increased slightly up to 30 kgIl0a. But. $S_2$, was increased up to 12 kg/lOa and then decreased slightly with N fertilization over the 12 kg/l0a. 3. Average increase in total dry matter yield to N fertilization were 23.85 kg, 7.97 kg and 5.08 kg DM for $S_0$, $S_1$, and $S_2$, respectively. 4. The level of 12 kg N/lOa is the limiting N level to obtain dry matter production under 60-709 shading conditions. 5. The contents of crude protein arid nitrate nitrogen were increased with shading and incremental N fertilization up to 30 kg/l0a. But, water soluble carbohydrate content was decreased greatly with high shading and high levels of N. 6. Nitrate nitrogen content indicated highly significant positive correlation with crude protein, but significant negative correlation with water soluble carbohydrate content. 7. At 30 kg N level with $S_1$, was necessary to exceed the potentially toxic nitrate nitrogen level of 0.20%.

• 한국환경복원기술학회지
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• 제7권1호
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• pp.110-115
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• 2004

This experiment was conducted to investigate the effect of light intensities on the growth responses, carbohydrate contents and the characteristics of leaf gas exchange in Miscanthus sinensis and Pennisetum purpurascens. The plant height and leaf length were increased to about 30% in the sun. However, those were reduced severely in the shade, and leaf necrosis was also observed. The representative growth index and the dry weight of 2 species were 50% higher than shade and the rate was reduced according to the decrease of light intensities. Total carbohydrate contents showed very similar changes to that of dry weight. However, any notable influences were observed at above the light intensities of 250~500${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ in the half shade. The size of spikes and the earliest spiking appeared in the sun and the spike color was decolorized as decreased in light intensities, irrespective of species. Photosynthetic rate of 2 species was 2 times higher in the sun than those in the shade, and it showed the typical photoresponses of sun plant. Stomatal conductances and intercelluar $CO_2$ concetration showed similar changes to that of photosynthetic rate. On the contrary, vapor pressure deficit was increased more in the shade than in the sun.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1980년도 학술대회지
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• pp.39-47
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• 1980

The harvesting and export of Canadian ginseng from the cool, shady hardwood forests of southern Canada can be traced to 1796. Because of its high dollar value and diminishing woodland supplies it was decided in 1896 that it should be cultivated under wood lath screens. Present day economics dictate changes in production techniques to allow for a decreasing supply of expensive labour. Traditional wooden lath screens have a surface area of wood of 70 per cent and permit light penetration of only about 18 per cent. Experimental woven black polypropylene shade has an estimated surface area of 72 per cent and permits light pentration of about 28 per cent. While differences in air and leaf temperatures under the two shade structures can be measured it is doubtful if these are great enough to cause differences in plant growth under the two structures. Shade grown ginseng had a low fresh and dry weight and total chlorophyll content (ratio of a to b was 3 to 1) comparable to other shade species. There was no differences in fresh and dry weight and chlorophyll content of leaves from plants grown under the two shade structures. Maximum net photosynthesis of leaves was 0.175 g $CO_2\;m^{-2}\;hr^{-1}$ and light saturation level was about $200{\mu}E\;m^{-2}\;s^{-1},$ or about 10 per cent of full sunlight.

• 임산에너지
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• 제21권3호
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• pp.46-53
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• 2002

본 연구에서는 인공피음에 의해서 광조건을 3단계로 달리하여 생육시킨 펜둘라자작나무, 층층나무, 물푸레나무를 대상으로 생장량과 물질생산량 등 특성을 조사하여 생리ㆍ생태적 특성을 밝히고자 연구를 실시하였다. 인공피음처리에 따른 조사 대상 수종의 묘고생장 차이는 거의 없었으며, 근원직경의 생장은 전광처리구가 투광율 7-10%의 피음처리구보다 상대생장율이 29-32% 이상 우수한 생장율을 나타냈다. 하지만 층층나무의 근원직경생장은 투광율 26-34% 처리구에서 높은 생장율을 나타냈다. 대부분의 수종에서 피음처리 수준에 따른 광량감소와 함께 총 물질생산량도 감소하였고, 잎과 줄기의 비율이 뿌리에 비해 증가하는 경향을 보였다. 유묘의 T/R율은 대부분의 수종이 피음의 강도가 강할수록 T/R율이 높아지는 경향으로 전광처리구의 0.51∼l.13보다 투광율 7-10%의 강피음처리구가 1.00∼2.27로 높게 나타냈다. 전체적으로 비교할 때 인공피음처리에 의한 광량이 감소할수록 SLA, LAR, LWR은 광환경의 변화에 따른 피음의 강도가 강할수록 통계적으로 유의적인 차이를 보이며 증가하였다.

• 한국작물학회지
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• 제61권3호
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• pp.196-207
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• 2016

In monsoon climates, persistent shade is a troublesome weather condition with an impact on the growth and yield of corn (Zea mays L.). We imposed 7, 14, 21, and 28 days of consecutive shade (CS) on Gwangpyeongok and P3394 corn hybrids at the beginning of the kernel filling stages. Shade had little impact on leaf area and dry matter accumulation in the stem and leaves. However, dry matter accumulation in the ear was severely reduced by approximately 28% and 53% after 14 and 28 days of CS, respectively. For the components of grain yield, 7 and 14 days of shade did irreparable damage to the number of filled kernels, the kernel number per ear row, and the percent of filled kernels, but did little damage or reversible damage after removal of the shade to the 100-grain weight and the row number per ear. Shade significantly reduced the relative growth rate (RGR) due to a decrease in the net assimilation rate (NAR). These results suggest that source activity limitation by shade during the kernel filling stages leads to the inhibition of sink activity and size. The yield of biomass, ear, and grain logistically declined as the length of CS increased. Probit analysis revealed that the number of days of CS needed to cause 25% and 50% reductions in grain yield were 3.7 and 23.1, respectively. These results suggest that the plant yield loss induced by shade at the beginning of the kernel filling stages is mainly achieved within the first 7 days of consecutive shade.