• Journal of the Korean Society of Earth Science Education
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• v.3 no.1
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• pp.1-8
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• 2010

The purpose of this study was to analysis the 6th students' conceptions of the nature phenomenon focused on the systematic characteristics. For this study, 12 students of the 6th grades participated in special class for testing their conceptions about the water cycle in the earth system. And we analyzed the outcomes of students' conceptions based on SBF conceptual representation. The results indicate that most of the subjects perceived that the water cycle in earth system wasn't complex system maintaining its existence and functions as a whole through the interaction of its parts but simple system maintaining some actions between atmosphere and hydrosphere, geosphere, biosphere(biological world). And they didn't perceive the characteristics of the water cycle whose all parts must be presented the change of volume between vapor and water, glacier proposing the total hydro-volume are established in the earth system. Based on the results, it was suggested that the main goals of the schools' science education should be to provide students who understand the water cycle system as attaching importance to form with the skills needed to coherent understanding of the essential qualities for the nature phenomenon system.

• Mycobiology
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• v.42 no.1
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• pp.1-5
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• 2014

The typical life cycle of filamentous fungi commonly involves asexual sporulation after vegetative growth in response to environmental factors. The production of asexual spores is critical in the life cycle of most filamentous fungi. Normally, conidia are produced from vegetative hyphae (termed mycelia). However, fungal species subjected to stress conditions exhibit an extremely simplified asexual life cycle, in which the conidia that germinate directly generate further conidia, without forming mycelia. This phenomenon has been termed as microcycle conidiation, and to date has been reported in more than 100 fungal species. In this review, first, we present the morphological properties of fungi during microcycle conidiation, and divide microcycle conidiation into four simple categories, even though fungal species exhibit a wide variety of morphological differences during microcycle conidiogenesis. Second, we describe the factors that influence microcycle conidiation in various fungal species, and present recent genetic studies that have identified the genes responsible for this process. Finally, we discuss the biological meaning and application of microcycle conidiation.

• Journal of Mechanical Science and Technology
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• v.18 no.4
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• pp.681-688
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• 2004

For use of the thermal cycle of the biochemical fluid sample, the isothermal temperature source with a large surface area was designed, fabricated and its thermal characterization was experimentally evaluated. The comprehensive overview of the technology trend on the temperature control devices was detailed. The large surface area isothermal temperature source was realized by using the vapor chamber heat spreader. The cost-effectiveness and simple manufacturing process were achieved by using the metal-etched wick structure. The temperature distribution was quantitatively investigated by using IR temperature imaging system at equivalent temperatures to the PCR thermal cycle. The standard deviation was measured to be within 0.7$^{\circ}C$ for each temperature cycle. This concludes that the presented isothermal temperature source enables no temperature gradient inside bio-sample fluid. Furthermore it can be applied to the cooling of the electronic devices due to its slimness and low thermal spreading resistance.

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.3
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• pp.82-84
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• 2008

A surface encoder based on the Half-shaded square pattern (HSSP) is presented. The HSSP working as reference grid is composed of the straight lines which are easy to be fabricated and make measuring time short. Since the periodic cell is separated in ON/OFF by the $45^{\circ}$ straight line, the duration from the starting point of scanning to the first rising edge and the duty cycle of the pulse train vary with respect to the position of the starting point. And the relationship between X and Y position and the duration, and duty cycle is described in the simple linear equation. Therefore, it is possible to measure X and Y position with the measured duration and duty cycle without calculating load. Through the test set-up, the feasibility of the proposed surface encoder was verified. Also the future works for improvement of performance were suggested.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.956-961
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• 2000

This paper describes the design of a small size Alkali Metal Thermal to Electric Converter (AMTEC) which employs a capillary structure for recirculating sodium working fluid. The cycle is based on the simple and small capillary type ${\beta}"$ -alumina and wick tube element. The proposed cell consists of the 37 conversion elements with capillary tube of $50{\mu}m$ in diameter and the sealed cylindrical vessel of 22mm in outer diameter. Results on the cycle analysis of sodium flow and heat transfer in the cell showed that the expected power output was 4.65W and the conversion efficiency was 19% for the source temperature of 900K.

• International Journal of Advanced Culture Technology
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• v.3 no.2
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• pp.67-76
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• 2015

This paper aims to study and design of Organic Rankine Cycle (ORC) Machine using Isopentane as working fluid expanding through Tesla turbine. The study on ORC machine expanding through Tesla turbine has result on the efficiency of Tesla turbine. In addition, Thermodynamics theory on isentropic efficiency proved to be a successful method for overcoming the difficulties associated with the determination of very low torque at very high angular speed. By using an inexpensive experiment device and a simple method, the angular acceleration method, for measuring output torque and power in a Tesla turbine is able to predict a tendency of output work. The experiments using two Tesla turbine sizes, the first size is 1.6 bigger than the second one. In comparison with the first size, the tesla turbine can produce power output more than 62% of the second size. Further study on the machine can be developed throughout the county due to its low cost and efficiency.

• Journal of the Chungcheong Mathematical Society
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• v.21 no.2
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• pp.259-268
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• 2008

To the design of secret key, there are two types of basic approaches called the tame approach and the wild approach. In the tame approach we try to use only simple primitives such as linear feedback shift registers and to prove mathematical theorems about their cryptographic properties. In the wild approach we try to use crazy compositions of operations which mix a variety of domains in a nonlinear and nonalgebraic way. There are several papers which try to bridge this gap by considering semi-wild constructions. A T-function on n-bit words plays an important role in semi-wild constructions. In this paper we study the invertibility and the period of some T-functions. Especially we characterize some polynomials which has a single cycle property.

• Journal of The Korean Association For Science Education
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• v.28 no.1
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• pp.24-31
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• 2008

This study aims at examining the concepts that apply in understanding the water cycle, to inquire into the concept related to the unit of earth structure that are taught in the Earth Science I. Analysis of word association, drawing and questionnaires showed that it was difficult for them to understand the water cycle within the earth system, and to put components into one integrated system together. In other words, it showed that they have a low standard of understanding in connection with the water cycle, that their understanding of water cycle are simple thoughts rather than systematic thought. It showed that they had an understanding of the atmosphere and hydrosphere to some extent, but they took no notice of the effect of the lithosphere or biosphere, nor do they have an understanding of its effect. Analysis of questionnaires showed that they have no well understanding of water cycle of cyclic nature, and that they have low standard of understanding of the components of water cycle.

• Communications of the Korean Mathematical Society
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• v.11 no.4
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• pp.1123-1135
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• 1996

In this paper, we introduce some properties of Steinhaus graphs of order n, and prove that the size of some special type of induced cycles in Steinhaus graphs of order n is bounded by $\left\lfloor \frac{n+3}{2} \right\rfloor$.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.192-198
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• 2000

Three dimensional thermal cycle analysis of the plunger is carried out in repeated forming process of the TV glass, which is continued work of two dimensional analysis where an efficient method has been proposed. The plunger undergoes temperature fluctuation during a cycle due to the repeated contact and separation from the glass, which attains a cyclic steady state having same temperature history at every cycle. Straightforward analysis of this problem brings about more than 90 cycles to get reasonable solution. An exponential function fitting method is proposed, which finds exponential function to best approximate temperature values of 3 consecutive cycles, and new cycle is restarted with the fitted value at infinite time. Number of cases are analyzed using the proposed method and compared to the result of straightforward repetition, from which one finds that the method always reaches nearly convergent solution within $9{\sim}12$ cycles, but turns around afterwards without further convergence. Two step use is found most efficient, in which the exponential fitting is carried out fer the first 12 cycles, followed by simple repetition, which shows fast convergence expending only 6 additional cycles to get the accuracy within 2 error. This reduces the computation cycle remarkably from 90 to 18, which is 80% reduction. From the parametric studies, one reveals that the overall thermal behavior of the plunger in terms of cooling parameters and time is similar to that of 2 dimensional analysis.