• Transactions of the Korean Society of Automotive Engineers
• /
• v.16 no.1
• /
• pp.45-51
• /
• 2008

This paper presents theoretical and experimental analysis on the characteristics of the power spectrum of electormagnetic waves radiating from the spark plug and their cables of a distributorless ignition system. The theoretical study was conducted applying the microwave transmission line theory and the antenna theory. The experimental works were carried out to measure the standing wave ratio(SWR) and the radiation power spectrum of this system. As a result, it has been found that a spark plug and its cable is working as a monopole antenna radiating elelctromagnetic waves. Because of its similar structure to a monopole antenna, the envelope of radiation power spectrum distribution has a bell shape which can be obtained from a monopole antenna operating as a series resonant circuit. The frequency characteristics from the SWR measurements show a similar frequency characteristics of power spectrum of the system studied. Also, it has been found that the density of the power spectrum of the system fitting a long time used spark plug is higher than that of fitting a new spark plug.

• Journal of the Korean Professional Engineers Association
• /
• v.24 no.6
• /
• pp.106-112
• /
• 1991

Electronics has different meanings to different people and in different countries. Hence, let me difine the term in the sense that it is used here. Electronics in the science and the technology of the passage of charged particles in a gas, in a vacumn, or in a semiconductor. The beginning of electronics came in 1895 when H. A. Lorentz postulated the existence of discrete charges called electrons. Two years later J.J. Thompson found these electrons experimentally. In the same year (1897) Braun built what was probaly the first electron tube, essentially a primitive cathode-ray tube. It was not until the start of the 20th century that electronics began to take technological shape. In 1904 Fleming invented the diode which he called a valve. This era begins with the invention of the transistor about 30 years ago. The history of this invention is interesting. M.J. Kelly, director of research(and later president of Bell Laboratories), had the foresight to realize that the telephone system needed electronic switching and better amplifiers. Vacuum tubes were not very reliable, principally because they generated a great deal of heat even when they were not being used, and, particularly, because filaments burned out and the tubes had to be replaced. In 1945 a solid-state physics group wa formed. The foregoing completes the history of electronics and electronic industries up to 1978. There is already a start toward a merging of the computer and the communication industries which might be called information manipulation. This includes storage of information, sorting, computation, information retrieval, and transmission of data. This combination of the computer and the communication fields will penetrate many disciplines. Applications will be made in the fields of law, medicine, biological sciences, engineering, library services publishing banking, reservation systems, management control, education, and defense.

• The Korean Journal of Ecology
• /
• v.18 no.3
• /
• pp.367-383
• /
• 1995

The relationship between floristic composition and soil environmental factors was investigated in the forest vegetation of Mt. Mohu.The forest vegetation unit of the Mt. Mohu could be divided into three communities, Quercus mongolica community, Pinus densiflora community and Quercus variabilis community. There were two subcommunities in Quercus mongolica community, which were Rhododendron schlippcubachii subcommunity and Stephanandra incisa subcommunity. The Quercus mongolica community was distributed at the altitude of 600~900 m, Pinus densiflora and Quercus variabilis communities were distributed on south-west slope at the altitudes of 430~520 m and 400~500 m, respectively.The DBH class of dominant species in each community showed that Quercus mongolica had 9 individuals/a at 11~15 cm class, Quercus variabilis 5.6 individuals/a at 11~15 cm class, and Pinus densiflora 8 individuals/a at 16~20 cm class. Quercus mongolica. Quercus variabilis and Pinus densiflora communities showed a bell-shape distribution.The contents of organic matter and soil water, and cation exchange capacity of the soil increased and the pH decreased in proportion to increased altitude. The soil environmental conditions of Quercus mongolica community were more favorable than those of Pinus densiflora and Quercus variabilis communities.The supposed successional sere of the forest vegetation of Mt. Mohu was as follows: Pinus densiflora community.Quercus variabilis community.Quercus mongolica community

• The Korean Journal of Ecology
• /
• v.1 no.1
• /
• pp.17-23
• /
• 1977

Flowering dates of 389 plant species in the Hongneung Arboretum, Seoul, had been recorded from 1968 through 1975. The thermal analysis on the air temperature as the key factor determining the first flowering date, with climatological data obtained in the Arboretum, were undertaken by Nuttonson's Index (1948) and Lindsey & Newman's Index (1956). The results and conclusion in this study are as follow; Peak in the bell shape distribution curve of the species and first flowering dates, largely, was early May. Flower spans of most species were 10 to 20 days, neverthless, some species flower only a few days while others may stay flowering a hundred days even more. Increase-curves of summation temperature from early spring through late-summer showed almost the same mode in both Nuttonson;s Index (Tn) and Lindsey & Newman's Index (T1). These Indices manifested the exponential curve, increasing slowly at the beginning of spring chiefly but rapidly from the middle part of April. The equation of the linear relationahip between Tn and Tl as far as in thisstudy is as follow. Tl=230Tn It appears that the distribution of summation temperature, below Tn=400°C·day, affects the first flowering, even though it could be modified somehow by the distribution of precipitation, day length and others. Nuttonson's Index (Tn.f) and Lindsey & Newman's Index (Tl.f) upon the thermal amount first flowering dates have been respectively simulated as follow. Tn.f=θa + C Tl.f=230θa + 230C where θ is air temperature 10°C, a and C are a constant.

• Journal of Periodontal and Implant Science
• /
• v.27 no.4
• /
• pp.805-818
• /
• 1997

Immune responses of periodontal tissue may be regulated by products of sensory afferent nerve endings such as neuropeptides. Substance P(SP), a tachykinin neuropeptide, has been previously reported to stimulate the activities of T lymphocyte. Therefore, I examined the role of SP in IL-2 production and cell proliferation by using a homogeneous line of T lymphocytes(Jurkat and HuT78). Cell proliferation rate was determined by [$^3H$]-thymidine incorporation test, and IL-2 was quantitated by the growth rate of CD4+ IL-2-dependent T lymphocyte line CTLL-2. SP stimulated cell proliferation of T lymphocytes at the concentration of $10^{-12}$ and $10^{-8}$M in a biphasic bell-shape dose-dependent manner. However, SP alone did not induce IL-2 release at the concentration range of $10^{-6}$ to $10^{-14}$M. The upregulation of IL-2 release was observed when $10^{-12}$M SP was applied together with mitogens such as Con A or PHA+PMA on T cell lines, especially on Jurkat. Con A or PHA+PMA demonstrated to increase the rate of cell proliferation of Jurkat, which had shown to produce much amount of IL-2 indicating that mitogen-induced cell proliferation might be partially influenced by released IL-2. It was concluded that regulatory effects of SP on the immune/inflammatory response could be mediated through the costimulatory upregulation of IL-2 production and increase of cell proliferation of T lymphocyte.

• The International Journal of Costume Culture
• /
• v.2 no.2
• /
• pp.45-59
• /
• 1999

The objectives of this study were to identify fashion trend in the late 1990's by using content analysis of the design elements of wedding dresses in wedding magazine photographs. The data were selected among the wedding dress photographs in 1997 issues of two wedding's magazines, 'My wedding'and 'She's Bride'. The identified 455 photographs were classified into 15 major-categories of silhouettes, necklines, sleeves, materials, and trimmings, etc. 15 major-categories were consisted of 232 sub-categories. In the late 1990's, fashion trends of wedding dresses have mixed mainly dome silhouettes(56.0%), bell silhouettes, and tubular silhouettes. One-piece forms(90.8%) were familar more than two-piece forms. Necklines were used mainly such as square neckline(14.0%), high necklines(13.0) blended with other off-shoulder necklines, heart-shape necklines, and sweet-heart necklines, etc. Also camisole and strapless were added in neckline. Long-tight sleeves dominated at the late 1990's because that were used most (21.1%) among 22 sleeves sub-categories. And short sleeve, ruffled below-elbow length sleeves, and french sleeves were also used with the other sleeves. Long length in skirts(98.4%) were common but mini length were used rarely. Satin, lace, and solid cloth were the main materials in wedding dresses, however, spandex and velvet were also used. Various trimmings such as flowers(corsages), ribbons blended with embroidery, small flowers, buttons, frills, strings, and fur trimming are used. Especially, flowers used most(11.8%) among 61 trimmings sub-categories. But simplicity was shown in trimmings because there were dresses not having any decorations(14.3%). The wedding dress of the late 1990's has become more varied in design due to the reflection of changes in society and fashion of everyday garments while the traditional design of the wedding dress has been preserved.

• IE interfaces
• /
• v.23 no.4
• /
• pp.337-348
• /
• 2010

The Bass model is the most widely used model in research of new product diffusion because it presents a nice explanation on the diffusion process of new products. However, it has a limitation that its performance of fitness is lower as the available data become less and also, the diffusion curve is bell-shape and so, it can not represent the various diffusion patterns. Recently, a two-pieces Bass model is developed and applied to analyze diffusion of 10 products. The results are encouraging in terms of fitness. However, diffusion pattern is not dealt with in the paper. In this paper, analysis of diffusion pattern is in depth addressed in two-pieces Bass model. It is shown that the diffusion curves are divided into 3 types with respect to the peak adoption rate and each type is divided into 2 types further. Takeoff time of a diffusion process is analyzed by using the inflection point and regime-change time where it represents the point that imitation and innovation parameters change. Empirical studies for 68 products(28 domestic products and 40 USA products) are performed to analyze the diffusion pattern. Findings are that diffusion patterns of all products except 1 USA product show type I and regime-change time becomes shorter as the introduction time of the product is later in domestic products and regime-change time can be regarded as a takeoff time in 47% of total 68 products.

• Journal of Plant Biology
• /
• v.29 no.2
• /
• pp.95-107
• /
• 1986

Seasonal changes in pool size, inflow rates in biomass and phosphorus, and the efficiency of phosphorus use in the stand of three populations (Helianthus tuberosus, Artemisia princeps and Phalaris arundinacea) in the basin of the Mt. Geumoh were investigated. During the early growing period, in the three species populations the relative size of the phosphorus pool of population was larger then that of its biomass pool, but that of the phosphorus pool of belowground part decreased more rapidly than that of its biomass pool. In the A. princeps and P. arundinacea populations, the phosphorus inflow rate was markedly high during the soil thaw in early spring and its seasonal change pattern was different from that of the biomass production rate, showing two peaks in March and June. But in the H. tuberosus population, the two seasonal change patterns were alike. The annual biomass production was 2283 gDM m-2 in the H. tuberosus, 1884 m-2 in the A. princeps and 1879 gDM m-2 in the P. arundinacea population, and the annual phosphorus inflow was 11.35, 9.63 and 7.60 gP m-2, respectively. The P. arundinacea population showed the smallest LAI peak(5.4 in early June), and the largest NAR peak (36.9 gDM m-2wk-1) RGR peak (0.15g g-1 wk-1) among the three species populations. The seasonal change patterns in whole plant EPU of the three species populations showed the bell shape, but the annual EPU values among them were markedly different. It was noticed that the population with the highest RGR showed the highest EPU among the three species populations while the population with the lowest RGR showed the lowest EPU among them.

• The Korean Journal of Zoology
• /
• v.14 no.4
• /
• pp.181-191
• /
• 1971

In Diplonichus esakii each ovary comprises five telotrophic ovarioles. In the fourth instar, the anterior part of the germarium consists of undifferentiated cells. The middle part contains a spherical trophic and the posterior part comprises young oocytes, followed by the upside downbell shape prefollicular tissue. The bell form is the standard characteristic in this instar larva, and the nutritive cord is found although somewhat indistinctly. In the fifth instar larva, the trophic core is elliptical form, and the oocyte is found at the base of the core. The oocytes are connected with the ocre by the nutritive cord. In the prefollicular tissue are also found some oocytes. In the adult, the vitellarium is filled by the developmental oocytes. The yolk granules inside each oocyte migrate from the base of the follicular epithelial cells to the center of the oocyte. Finally, the ooplasm of the oocyte becomes completely homogeneous. Therefore, according to the advancing of instars the nutritive cord developes completely before the oocyte has chorion and the follicular epithelial cell binucleates. The upper part of the ovariole consists of unchorionated oocytes, and the proximal part comprises chorionated oocytes in the adult.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.4 no.2
• /
• pp.122-126
• /
• 1983

The allocation of the dry-matter yield in Miscanthus sineusis grasslands on soils of different water contents was investigated. The results obtained in this study can be summarized as follows; 1. The standing crops of Miscanthus sineusis grassland A (soil water content; 22.54%) and B (soil water content; 9.22%) were 2,267.12 and 943.44 g/m$^{2}$, respectively. 2. The productivity curves of the Miscanthus sineusis grassland A and B were the bell-shape and the productivity peak values were showed in September. 3. In Miscanthus sineusis grassland A and B, the reproductive allocation was represented by characteristics of production structure and dry-matter yields. 4. Allocation rates of dry-matter yields to panicle and rhizomes in Miscanthus sineusis grassland A and B were 0.6 and 1.4% and 35.4 and 46.6% respectively. 5. In these results, allocation of dry-matter yield to reproductive organs was increased in the condition of water-stress.