• Vacuum Magazine
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• v.2 no.1
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• pp.17-20
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• 2015

In this article, a historical and scientific review on the development of an ultrafast electron microscope is supplied, and the challenges in further improvement of time resolution under sub-picosecond or even sub-femtosecond scale is reviewed. By combining conventional scanning electron microscope and femtosecond laser technique, an ultrafast electron microscope was invented. To overcome its temporal resolution limit which originates from chromatic aberration and Coulomb repulsion between individual electrons, a generation of electron pulse via strong-field photoemission has been investigated thoroughly. Recent studies reveal that the field enhancement and field accumulation associated with the near-field formation at sharply etched metal nanoprobe enabled such field emission by ordinary femtosecond laser irradiation. Moreover, a considerable acceleration reaching 20 eV with near-infrared laser and up to 300 eV acceleration with mid-infrared laser was observed, and the possibility to control the amount of acceleration by varying the incident laser pulse intensity and wavelength. Such findings are noteworthy because of the possibility of realizing a sub-femtosecond, few nanometer imaging of nanostructured sample.in silicon as thermoelectric materials.

• Korean Journal of Microbiology
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• v.28 no.4
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• pp.290-296
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• 1990

Putrescine, spermidine, and spermine were found to persent in Methylobacterium extorquens AM1 growing on methanol, succinate, glucose, or nutrient broth as an energy source. Spermidine was found to be a major polyamine in cells growing on methanol or succinate, while putrescine to be the one in nutrient broth-grown cells. The overall content of polyamines in cells growing on glucose was less than that in cells growing on other substrates. Spermine was the most abundant polyamine in glucose-grown cells. Accumulation of polyamines in M. extorquens AM1 was maximal at the mid-exponential or early stationary phase during growth on each substrate. The effect of polyamines added into the medium on the polyamine composition in M. extorquens AM1 was variable. Each polyamine added into the nutrient broth medium was found to increase the amount of the respective polyamine in the cell. Exogeneously added polyamines had no effect on the growth of M. extorquens AM1.

• YAKHAK HOEJI
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• v.12 no.3_4
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• pp.76-84
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• 1968

When 19-hydroxycholesterol acetate was added into CSD-10 in Nutrient Broth or in a mineral salts medium consisting of KH$_{2}$PO$_{4}$(0.1%), $K_{2}$HPO$_{4}$(0.1%), NH$_{4}$NO$_{3}$(0.1%), MgSO$_{4}$(0.02%), CaCl$_{2}$(0.002%), and FeCl$_{3}$(0.005%), a substantial amount of 19-hydroxyandrost-4-ene-3,17-dione was accumulated prior to accumulation of estrone. From this result and all of previous works, a tentative degradation pathway of 19-hydroxycholesterol acetate to estrone by CSD-10 was derived. 19-hydroxyandrost-4-ene-3,17-dione seems to be an attractive intermediate for the synthesis of 19-norsteroids.

• Management & Information Systems Review
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• v.3
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• pp.439-460
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• 1999

The purpose of this paper is to compare the characteristics between group that has only one credit card and group that has multiple credit cards in each stage of purchase decision making based on the literature in consumer behavior. Results indicated that (1) The number of credit cards that consumers has was affected by internal factor and reference factor, (2) depending on the number of credit cards, usage frequency, amount, and duration were differently showed and (3) inertia, point accumulation, and convenience were founded as determinants of using credit cards. Finally, theoretical and managerial implications of these findings are discussed.

• Journal of Sasang Constitutional Medicine
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• v.15 no.1
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• pp.123-128
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• 2003

Hydrocele is an accumulation of serous fluid greater in amount than the few drops normally present within the two layers of the tunica vaginalis. The most common type is simple hydrocele, in which the normally formed tunica vaginalis is distended with fluid. The case is a report about an old man with hydrocele. The hydrocele is founded by pelvis sono. Treatment was Herb-medication and rest. And the size of hydrocele and symptoms were reduced.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.263-264
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• 2006

In this paper, an efficient and fast algorithm to reduce calculation amount of FIR(Finite Impulse Responses) filtering is proposed. Proposed algorithm enables arbitrary size of parallel processing, and their structures are also easily derived. Furthermore, it is shown that the number of multiplication/sample is reduced, and number of instructions using MAC(Multiplication and Accumulation) processor are also reduced. For theoretical improvement, numbers of sub filters are compared with those of conventional algorithm. In addition to the theoretical improvement, it is shown that number of element for hardwired implementation are reduced comparison to those of the conventional algorithm.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.44-50
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• 1996

Accumulation of worn-out automobile tires creat fire and health hazards. As a possible solution to the problem of scrap-tire disposal, an experimental study was conducted to examine the potential of using tire chips as aggregate in Railroad block. This paper examines strength and toughness properties of Railroad block in which different amounts of rubber-tire particles of several sizes were used as aggregate. The Railroad block mixtures exhibited lower compressive, bending than did normal block. However, these mixtures did not demonstrate brittle failure, but rather a ductile, plastic failure, and had the ability to absorb a large amount of plastic energy under compressive loads.

• The Korean Journal of Ecology
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• v.21 no.5_1
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• pp.427-433
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• 1998

The standing crop and net production were estimated in Moojaechi on Mt. Jungjok. By using the decay model of organic carbon, absolute year of bog peat was calculated. Pollen analysis to bog peat revealed vegetational history and climate change around Moojaechi. The time required for amount of the accumulated peat in the bog was estimated in terms of the balance of the accumulation and decay of organic carbon of the deposit peat. Absolute year of the peat surveyed in this study was about 314 years. Pollen of Pinus was predominant in all the pollen zone, Geamineae and Cyperaceae increased in lower pollen zone while Pinus in upper pollen zone. This showes that climate of the past was probably more humid than that of present. In addition, middle pollen zone showed warming trend which is suggested by high pollen concentration of Quercus, Juglans, Carpinus and Corylus. It suggests that overall environment and vegetation were changed from warmer and more humid to dry condition in Moojaechi and it is considered as the course of boggy ground formation by retrogressive successions.

• Journal of the Korean earth science society
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• v.28 no.5
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• pp.598-602
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• 2007

A long-term in situ observation was carried out in the Ice-valley at Milyang in order to explain the factors and processes associated with the summertime ice formation. The variation of temperature inside Ice-valley in relation with ice formation in summer time was found to depend on precipitation rate in spring and cold air sinking in autumn and winter. The rate of temperature rising tends to correspond to sensible heat release depending on the precipitation amount at the freezing location. The reason of the cold air accumulation in a talus in the Ice-valley is the cold air sinking over the surface of talus due to the occurrence of outside clod air mass and the accumulated cold air from autumn to spring flow outside at the bottom of talus. The out-flowing cold air can result in the ice formation in the hot summer.

• KIEAE Journal
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• v.9 no.6
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• pp.3-11
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• 2009

Building materials have a great impact on the health of a building's occupants. Thus, it is imperative that their health-related properties be taken into during the course of construction project. Unfortunately, no current database system exists that can provide information on the health performance of building materials at each stage of construction project management, from planning and design to building and maintenance. therefore, an inordinate amount of time and effort is required to choose the right health-friendly materials(DBHM). To solve this problem, this study aims at building a database management system for health-friendly building materials. It analyzes the health-related properties and performance of various materials, and proposes a database structure and operation algorithm. The system proposed in this study is expected to contribute to the objective evaluation of health-friendly building materials through the accumulation of relevant data.