In this paper two aspects of the percolation and conductivity of carbon black-filled polyethylene matrix composites will be discussed. Firstly, the percolation behavior, the critical exponent of conductivity of these composites, are discussed based on studying the whole change of resistivity, the relationship between frequency and relative permittivity or ac conductivity. There are two transitions of resistivity for carbon black filling. Below the first transition, resistivity shows an ohmic behavior and its value is almost the same as that of the matrix. Between the first and second transition, the change in resistivity is very sharp, and a non-ohmic electric field dependence of current has been observed. Secondly, the electrical conduction property of the carbon black-filled polyethylene matrix composites below the percolation threshold is discussed with the hopping conduction model. This study investigates the electrical conduction property of the composites below the percolation threshold based on the frequency dependence of conductivity in the range of 20 Hz to 1 MHz. There are two components for the observed ac loss current. One is independent of frequency that becomes prevalent in low frequencies just below the percolation threshold and under a high electrical field. The other is proportional to the frequency of the applied ac voltage in high frequencies and its origin is not clear. These results support the conclusion that the electrical conduction mechanism below the percolation threshold is tunneling.

Temperature dependency of resistivity of the carbon black-polyethylene composites below and above percolation threshold is studied based on the electrical conduction mechanism. Temperature coefficient of resistance of the composites below percolation threshold changed from minus to plus, increasing volume fraction of carbon black; this trend decreased with increasing volume fraction of carbon black. The temperature dependence of resistivity of the composites below percolation threshold can be explained with a tunneling conduction model by incorporating the effect of thermal expansion of the composites into a tunneling gap. Temperature coefficient of resistance of the composites above percolation threshold was positive and its absolute value increased with increasing volume fraction of carbon black. By assuming that the electrical conduction through percolating paths is a thermally activated process and by incorporating the effect of thermal expansion into the volume fraction of carbon black, the temperature dependency of the resistivity above percolation threshold has been well explained without violating the universal law of conductivity. The apparent activation energy is estimated to be 0.14 eV.

In order to obtain the fundamental data for the marine ranch, this paper was carried out to investigate cortisol variation in blood according to adapted time in the measurement of auditory threshold. The groups were adapted at the experimental tanks for 0.5, 1, 3 and 6 hours, respectively. At the results, cortisol concentration had a deep connection with adapted time. In particular, cortisol concentration in the experimental group of 1 hour was significantly increased, whereas others showed no difference comparing with the control group. When classical conditioning method with the sound coupled with a delayed electric shock was given after the adapted time of 1 hour and 6 hours, the rate of the conditioning completion for 6 hours was higher than that of 1 hour. Therefore, this suggests that the sufficient adapted time was required for the accurate auditory threshold.

Grey field slug, Deroceras reticulatum Muller, is one of the major pests of chinese cabbage, Brassica campestris. To determine the economic thresholds of grey field slug on chinese cabbage, the slugs were inoculated after planting 1 week into chinese cabbages with a density of 0, 2, 4, 8, 16 slugs per 16 chinese cabbages(1㎡) at the plastic house in the spring and autumn of 2008. The rates of damaged cabbages by slug inoculation were 10.7% at 2 slugs and 42.7% at 16 slugs in the spring, and 20.3% at 2 slugs and 59.2% at 16 slugs in the autumn. The linear relationships between the initial slugs density and yield reduction of chinese cabbage were as following ; Y = 286.07x + 548.62, R2=0.9524(in the spring cultivation), Y = 318.91x + 998.05, R2=0.9323(in the autumn cultivation). Based on these results, the economic threshold of grey field slug per 16 chinese cabbages(1㎡) was 2.52 slugs in the spring and 0.86 slugs in the autumn.

Cage experiments by artificial infestations with different initial densities of Frankliniella occidentalis were conducted to analyze damages and develop control thresholds of F. occidentalis on greenhouse eggplant in 2005 and on greenhouse sweet pepper in 2007. In the eggplant experiment, the infestations of F. occidentalis resulted in direct damage on fruit surface and non-marketable fruits which had several thin or thick lines or bleaching patches on the surface. F. occidentalis adults were frequently found on the flowers of eggplants, while nymphs were mainly observed on leaves. The fruit yield of eggplants was not significantly different among experimental plots with different initial density of F. occidentalis. Relationship between % non-marketable fruits among harvested fruits of eggplant and sticky trap catches of F. occidentalis (no. thrips/trap/week) at two weeks before the harvest showed a positive correlation. Using the estimated relationship, the control threshold of F. occidentalis on greenhouse eggplant was estimated at 10 adults per week at two weeks before the harvest when 5% of non-marketable fruit was applied for the gain threshold. In the experiment of sweet pepper, the direct damage by F. occidentalis was observed on the fruit surface and calyx, and the marketable grade of the damaged fruits decreased. The significant yield loss of marketable fruits was found in plots with high initial introduced-densities. There was a high relationship between thrips density and percentage of damaged fruits. Assuming 5% yield loss (non-marketable fruit) for the gain threshold, the control threshold of F. occidentalis on greenhouse sweet pepper was 4.8 adults per trap and 0.9 individuals per flower at two weeks before harvest.

This study was conducted to develop the economic threshold for the diamondback moth (Plutella xylostella (L.) on Leaf Broccoli (leaf vegetable) in 2007. To investigate the relationship between initial density of diamondback moth larvae and broccoli leaf yield, experimental plots with five treatments (0, 0.5, 1.0, 2.0, 4.0 larvae per plant) as initial density were established. We inoculated larvae in chesses cloth covering to survey larvae density change. When grown to eat, leaves of broccoli were harvested by periods. 60-70% of larvae were removed whenever we picked the leaves. High levels of larvae were associated with significant reductions in leaf yield. There were 85%, 64%, 58%, and 56% yield reductions from the diamond back moth larvae density in 0, 0.5, 1,0, 1.5, 2.0 per plant, respectively 25days after larvae inoculation. The regression equation used to predict leaf yield based on the number of initial larvae density per a plant was y=1635-393x(R2=0.79***). The economic injury level of diamondback moth on leaf broccoli was 2-3 larvae per 10 plants for a damage level of 5%. The economic thresholds was 1-2 larvae per 10 plants. Thus, the diamond back moth management should be initiated 1-2 larvae occurrence per plant.

Western flower thrips, Frankliniella occidentalis(Perg.), is one of the major pests of lettuce, Lactuca sativa. To develop the economic thresholds for western flower thrips on lettuce, the thrips was inoculated into two types of lettuce, green deeply lobed leaf lettuce which was harvested every week and red frilled & crinkled leaf lettuce which was harvested one time, with a density of 0, 1, 3, 7, 10 thrips per one lettuce after planting 1 week and 3 weeks at the plastic house in 2006, and 0, 1, 3, 5, 7 thrips per one lettuce after planting 1 week in 2007. There was close correlation between the initial thrips density and the marketable quantity of lettuce : y = -155.36x + 3564.7, r2=0.9724('06), y = -167.82x + 3474.5, r2=0.8897('07) in the green deeply lobed leaf lettuce inoculated the thrips after planting 1 week, y = -109.65x + 3549.1, r2=0.9384('06) in the green deeply lobed leaf lettuce inoculated the thrips after planting 3 weeks, y = -197.09x + 3334.9, r2=0.9707('06), y = -244.08x + 3425.9, r2=0.8914('07) in the red frilled & crinkled leaf lettuce inoculated the thrips after planting 1 week, y = -101.07x + 3457.6, r2=0.7334('06) in the red frilled & crinkled leaf lettuce inoculated the thrips after planting 3 weeks. The economic threshold for western flower thrips on lettuce was ranged 0.20～0.30 thrips per one lettuce in the blue type lettuce and 0.14～0.33 thrips per one lettuce in the red type lettuce.

This study aimed to estimate control thresholds (CTs) for imported cabbage worm, Artogeia rapae L., injuring chinese cabbage in the field. As a preliminary experiment, five level of densities of second instar larvae of A. rapae were inoculated on plant and checked injury rates under greenhouse condition. Average leaf area consumed for one week by a second larva was 657.7㎟ to the 3-WAT (week after transplanting) and 2495.8㎟ for two weeks to the 6-WAT, respectively. In field experiment, different larvae densities of A. rapae ranged from one to seven were inoculated on 20 plants. The percent yield reduction (Y) of chinese cabbage infested by different densities of A. rapae (X) for a three-week period were estimated by the following equation; (1) Y=1.764X-0.3049 (R2=0.9901) for the 3-WAT; and (2) Y=1.0305X-0.2976 (R2=0.9398) for the 6-WAT. Based on the relationships between the densities of A. rapae larvae and the yield index of chinese cabbage, the number of second instar larvae which caused 5% loss of yield (Gain threshold proposed by Japan), was estimated as 0.15 per plant for the 3-WAT and 0.26 for the 6-WAT.

본 논문에서는 진동대를 이용하여 고층 건축물의 수평진동에 대한 지각임계가속도를 측정하였다. 바람에 의한 초고층 건축물의 과도한 진동은 거주자들에게 시각차와 현기증 같은 불쾌감을 줄 수 있다. 초고층 건축물 거주자들에게 쾌적한 환경을 제공하기 위해서는 가속도를 제한할 필요가 있다. 초고층 건축물은 1차 고유주기에 지배적이다 본 연구진은 1차 고유주기를 재연하기 위해 진동대를 사용하여 사인파진동에서 실험을 수행하였다. 실험은 진동하우스를 제작하고, 건장한 40명의 피험자를 대상으로 실시하였다 40명의 피험자를 8명씩 5개조로 나누고, 특정주파수범위에서 가속도를 증가시키면서 수평진동에 대한 인지도를 측정하였다. 수평진동실험으로 피험자들의 진동에 대한 인지도를 누적분포표로 만들고, 의 누적분포에 대해 추세선을 그려서 성능평가곡선을 작성하였다.

대부분의 후각 감성평가 연구에 있어서는 모든 피험자에게 동일한 농도의 냄새 시료를 제시하고 있다. 하지만 피험자의 후각 기능은 노화 등을 비롯한 여러 가지 요인으로 다를 수 있고 이러한 차이는 후각 감성에 영향을 미칠 수 있다. 따라서 본 연구에서는 후각 감성평가 시 냄새 시료를 제공하는데 있어서, 모든 피험자에게 동일한 시료를 제공한 경우와 피험자 개개인의 후각 역치를 고려하여 냄새 시료의 농도를 조절한 후 제공한 경우에 있어서 후각 감성특성 및 감성구조에 차이를 보이는 지 알아보았다. 피험자는 만 19세 이상 대학생 남녀 30명(남자: 18명, 여자: 12명)이었고 사용된 냄새 시료는 T&T olfactometer의 다섯 가지 냄새 기준물질이었다. 동일한 피험자에게 두 가지(실험 1과 실험 2)의 실험을 수행하였는데, 실험 1에서는 피험자 개개인의 후각 역치를 기준으로 냄새 물질의 농도를 조절하여 제공함으로써 모든 피험자가 동일한 냄새 강도를 지각하도록 가였다. 실험2에서는 모든 피험자에게 동일한 농도(+1)의 냄새 시료를 제공하였다. 실험 수행 결과, 냄새 시료 제시 방법(후각 역치 고려 유무)에 따라 후각 감성특성에 있어서 유의적인 차이를 보였는데 냄새에 대한 선호도가 명확하지 않은 시료에 있어서 이러한 차이가 더 크게 나타났다. 이러한 차이는 후각 감성구조에도 영향을 미쳤는데, '심미성', '강도', 그리고 '활동성'은 공통요인이었고, '친화성'(실험 1)과 '중량감'(실험 2)은 후각 역치 고려 유무에 따라 다르게 나타났다. 이러한 결과들을 통해 볼 때, 피험자의 후각 역치 고려 유무에 따라 후각 감성특성 및 감성구조가 다르게 나타날 수 있다고 볼 수 있겠다. 따라서, 냄새 시료에 대한 후각 감성평가를 수행하고자 할 때, 피험자의 후각 역치 및 기능과 이에 따른 냄새 시료 제시법 또한 신중하게 고려해야 할 것으로 사료된다.

본 논문에서는 진동대 실험을 통한 수평진동에 대한 체감도를 평가하고자 한다. 먼저 국외선행 연구를 조사하여, 실험의 적절한 방향을 모색하였다. 실험은 1차원 수평 진동대를 사용하고, 무빙룸은 우리가 생활하고 있는 공간과 유사하게 설계 및 제작하였다. 실험평가방법은 피험자를 40명 모집하여, 8명씩 5개조로 나누어 주파수 0.2Hz~1.2Hz 범위에서 가속도를 증가시켜 체감도에 대해 평가하였다. 수평 진동 실험으로 얻어진 체감도 누적분포를 0~20%, 21~40%, 41~60%, 61~80%, 81~100%로 나누어 추세선을 그려서 성능평가곡선을 작성하였다. 또 국외 사용성 평가기준에 반영된 설문지를 바탕으로 실험에 적합한 설문지를 제작하여, 진동에 대한 피험자들의 느낌을 조사하였다. 실험결과를 주파수에 따른 지각임계가속도로 평가하였다. 그리고, 인간의 수평진동지각에 대해 감각적요소 즉 시각적, 청각적요소가 얼만큼 영향을 주는지 정량적으로 평가하였다.

This study was conducted to examine the problems that would arise in our cropping systems when introducing Gain Threshold (GT) which is an important element in determining Economic Injury Level (EIL). Gain Threshold (GT) can be defined as the amount of damage (= yield loss) to justify management, and calculated by dividing the management costs by the market crop price. GTs for some pests in rice, soybean, and greenhouse vegetable crops cultivation were estimated and also compared with those in foreign countries. GTs and percentage of yield loss equivalent to them were estimated to be 4.6-6.1 ㎏/10a/season and 1.0-1.3% for brown planthopper, white-backed planthopper, rice water weevil, and sheath blight, whereas for rice blast in rice cultivation were 12.7 ㎏/10a/season and 2.7%. In soybean cultivation, the values for bean bug were 6.2 ㎏/10a/season and 3.6%. GTs and percentage of yield loss estimated for melon thrips, whitefly, and downy mildew in cucumber cultivation were 10.0-12.6 ㎏/10a/week, 1.4-1.7%, and the values for two spotted mite and gray mildew in strawberry cultivation were 3.1-3.5 ㎏/10a/week, 1.3-1.5%, and the values for American leaf minor, whitefly, and gray mold in tomato were 8.4-9.7 ㎏/10a/week, 1.7-1.9%. Overall GTs in our cropping systems were so low compared to those in foreign countries, which meant that the low GTs might yield the low EILs. Therefore, we could suggest that prior to direct introduction of GTs calculated from current cultivation systems in developing EILs it is necessary to seriously consider reasonable values of GTs or the yield loss equivalents to them.

W. B. Yeats began to write his works when Ireland was struggling for its independence from England. Young Yeats hoped to be a national poet and was naturally concerned about the future of his fatherland. The way Yeats chose for his country was a cultural one, not a military or political one. He believed in the Irish people’s artistic sensibilities and believed that his country could be a healthier and better country than England through the ’Unity of Culture’. Yeats was attracted to drama because of its usefulness as a public art. He wanted to establish a national drama based on Irish folklore and myth. He believed that drama could achieve or revive the ’Unity of Culture’ which he equated with the national unity of Ireland. Yeats’s main idea was that to achieve ’Unity of Culture’, the support of common people for art would be essential. Yeats’s early play, The King’s Threshold shows the unity of the poet and common people well. The story is based on an Irish myth. The king, a man of action, banishes Seanchan the poet, a man of words, from his court (affairs of state) and the poet choose to die on a hunger-strike for his rights in the court, that is, for the value of art in society. The poet works for the common people and expects their support, of which the king is much afraid. The King’s Threshold dramatizes the theme that concerned Yeats so deeply, the role of art in society. And another main point of the play is that poetry transcends politics. Yeats satirizes the defects and deficiencies of a society which no longer recognizes the artist’s role. But the poet dies, and we are not shown any effect that his death may have had on either society or the individual. The modern Irish people were not what the young poet had expected. Though the young poet’s dream for the ’Unity of Culture’ may be naive, the play shows us Yeats’s view of art and his belief in the poet’s role in society.

The purpose of this study was to compare the experimental pain threshold when used in luminous lamp radiation and nonluminous lamp radiation with healthy person. Thirty normal subjects were randomly assigned two groups: a luminous lamp radiation group, and a nonluminous lamp radiation group. The infrared lamps were applied on L3 for thirty minutes. Each group was measured for experimental pain threshold and local temperature before, 15 and 30 minute radiation. For statistical differences in change of the experimental pain threshold and local temperature due to differences in lamp ray was compared using the independent t-test. And, General linear model for profile plots test was used. The results were as: 1. Local temperature was significantly increased in the nonluminous lamp group (p<.01). 2. Experimental pain thershold was significantly increased in the luminous lamp group (p<.05),(p<.01). This study indicate that luminous lamp radiation was more effects of increase experimental pain thershold than nonluminous lamp radiation. Further study is needed to compare the effects of after period radiation.