• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.2
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• pp.164-172
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• 1983

The present study was conducted to investigate the variations in morphological traits, yield and yield-related components of rice cultivars exposed to different weather conditions by growing at the locations with different altitude but with equal latitude. Three Japonica varieties (Daegoldo, Jinheung, Shin #2) and three Tongil type semi-dwarf varieties(Josaengtongil, Suweon 287, wx 817-65-2-3) were seeded at Suweon on April 21 and transplanted at Suweon ($127^{\circ}$ N37 20', altitude 37m) and Jechun ($128.2^{\circ}$, N37 10', altitude 280-300m) on June 1 with the spacing of 30 $\times$ 15 em. The morphological traits, yield and yield-related components were measured. Culm length, paincle length and 1000-grain weight showed a little increase in Japonica varieties in Jechun as compared to those in Suweon and vice versa in semi-dwarf varieties, showing no significant differences. Number of panicles, per hill and number of spikelets per panicle among yield-related components showed remarkable increase in all varieties in Jechun as compared to those in 'Suweon but such inter-locational differences differed with varieties within varietal group and between varietal groups. On the contrary, grain fertility was higher in Suweon than that in Jechun and in Japonica varieties than that in semi-dwarf varieites , showing greater inter-locational difference in semi-dwarf varieties. Among Japonica varieties Jinheung and Shin #2 showed remarkable increase in yield in Jechun as compared to that in Suweon but in semidwarf varieties it was just the opposite. The importance of each of the yield-related component contributing to yield showed similar tendency 'regardless of locations in Japonica varieties. However, it was evidently different between locations in semidwarf varieties, where number of spikelets per panicle showed greatest direct effect on yield in Suweon but in Jechun so did grain fertility followed by the number of spikelets per panicle.

• Interaction and multiscale mechanics
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• v.5 no.1
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• pp.27-40
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• 2012

The two-dimensional incompressible flow of a linear viscoelastic fluid we considered in this research has rapidly oscillating initial conditions which contain both the large scale and small scale information. In order to grasp this double-scale phenomenon of the complex flow, a multiscale analysis method is developed based on the mathematical homogenization theory. For the incompressible flow of a linear viscoelastic Maxwell fluid, a well-posed multiscale system, including averaged equations and cell problems, is derived by employing the appropriate multiple scale asymptotic expansions to approximate the velocity, pressure and stress fields. And then, this multiscale system is solved numerically using the pseudospectral algorithm based on a time-splitting semi-implicit influence matrix method. The comparisons between the multiscale solutions and the direct numerical simulations demonstrate that the multiscale model not only captures large scale features accurately, but also reflects kinetic interactions between the large and small scale of the incompressible flow of a linear viscoelastic fluid.

• Structural Engineering and Mechanics
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• v.20 no.2
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• pp.225-239
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• 2005

Applications of the Trefftz boundary element method (BEM) to anti-plane electroelastic problems are presented in this paper. Both direct and indirect methods with domain decomposition are discussed in details. Each crack is treated as semi-infinite thin slit defined in a subregion, for which a particular solution of the anti-plane problem, satisfying exactly the crack-face condition, is derived. The stress intensity factors defined at each crack tip can be directly computed from the coefficients of the particular solution. The performance of the proposed formulation is assessed by two examples and comparison is made with results obtained by other approaches. The Trefftz boundary element approach is demonstrated to be suitable for the analysis of the anti-plane problem of piezoelectric materials.

• Korean Journal of Mathematics
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• v.22 no.1
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• pp.151-167
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• 2014

Let M, N be modules over a ring R and $[M,N]=Hom_R(M,N)$. The concern is study of: (1) Some fundamental properties of [M, N] when [M, N] is regular or semipotent. (2) The substructures of [M, N] such as radical, the singular and co-singular ideals, the total and others has raised new questions for research in this area. New results obtained include necessary and sufficient conditions for [M, N] to be regular or semipotent. New substructures of [M, N] are studied and its relationship with the Tot of [M, N]. In this paper we show that, the endomorphism ring of a module M is regular if and only if the module M is semi-injective (projective) and the kernel (image) of every endomorphism is a direct summand.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1995.04a
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• pp.28-34
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• 1995

Behavior of underground structural systems is usually complicated because of various unknown parameters. In order to construct those structural systems safely and economically, exact identification of the system parameters and accurate analysis of the system behaviors are essentially required. In this study, a forward analysis program, which is able to eliminate numerical errors due to far field boundary effect, is developed by coupling finite and boundary elements. In this coupled analysis, boundary elements are used in the semi-infinite domain where stress variation is small, and finite elements in the stress concentration region where material nonlinearity should be considered. Then, a back analysis program which can identify the system parameters is developed using the direct method to be combined with the forward analysis program. The elastic modulus and initial stress, which are most important in the description of the behavior of underground structures, are taken as the system parameters. A simple example is examined 0 show that the method can be used effectively.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.5
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• pp.338-346
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• 2001

An infrared imaging method in which direct measurement of energy gap variations can be achieved by digital image processing is proposed. This method allows economic and easy evaluation of the temperature coefficients of a semiconductor energy gap. The key components of the method are a polychromator, a computer equipped with a frame grabber and a variable temperature cryostat. Tentative experimentation conducted on LEC grown semi-insulating GaAs has resulted in a fairly good agreement with the theoretical model. This proposed method could be applicable for most compound semiconductors.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.588-590
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• 1996

An AC induction motor or constant speed characteristics has been widely used as power source because of simple structure and low maintenance cost in industrial field. The variable frequency AC source with a conventional inverter which is composed or power semi-conductors and drive systems contains much noises in sine wave current due to high speed switching or direct current. In this paper, the low pass LC filter for a variable speed induction motor driven by a full bridge inverter is introduced to solve EMI problem originated by much noise current. The modified LC filter based on the 3rd order Butterworth LC filter is used for the computer simulations and real experiments. The characteristics or proposed LC filter are investigated through FET analysis.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.783-788
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• 2001

Voids created with concrete construction or deterioration result in serious weakness from the aspects of both structural and durable function. Ultrasonic method using image processing technique was used for detecting pattern of voids in concrete in this study Experimental investigation was carried out for three types(patterns) of void in concrete. The effect of curing period of concrete and ultrasonic measurement method was also investigated. As a result it has been verified that the semi-direct measurement method is more effective than the other methods for detecting pattern of voids in concrete in ultrasonic method using image processing technique. The longer the curing period of concrete is, the better the detection accuracy of void pattern can be obtained.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.2
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• pp.135-141
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• 2001

차량 충돌시 자동차의 시트는 승객 및 운전자를 보호해야 한다. 따라서 자동차시트는 충분한 강도를 가져야 하며 이것은 여러 가지 법규에 의해서 제재되고 있다. 물리적 실험 결과가 법규에 정한 규정치를 만족시키기 위해 과대설계 될 수 있다. 그러나 이것은 연비를 줄이기 위한 경량화의 만족이라는 설계요구에 상충한다. 본 논문에서는 헤드레스트 강도시험을 시뮬레이션하고 과대 설계되어 있다고 판단되는 어퍼암을 최적화 모델로 최적설계를 수행하였다. 순차 이차 계획법인 PLBA 알고리즘과 민감도 해석을 위하여 직접근사해석법을 사용하였다.

• Mass Spectrometry Letters
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• v.6 no.4
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• pp.99-104
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• 2015

A liquid chromatography mass spectrometry (LC-MS) system was used to identify and distinguish oligostilbene diastereoisomers. A polyphenolic extract from Neobalanocarpus heimii known to be rich in oligostilbenes of various degrees of condensation was used as test material. Fourteen oligostilbenes were isolated from this extract on a fully automated semi-preparative HPLC system. Out of these, two pairs of dimers, one pair of trimers, two pairs of tetramers and a group of four tetramers with similar skeleton were identified as diastereoisomers. Their structures and configurations were established by spectroscopic methods. All isolated compounds were subjected to an LC-MS/MS to study their fragmentation patterns. The experiments were performed on a liquid chromatography-mass spectrometry (LC-MS) with electrospray-ionization (ESI) interface in positive mode. MS/MS spectra of each pure compound were recorded by direct infusion in identical conditions and their product ion spectra were analysed. Some subtle yet significant differences were observed between the spectra of oligostilbenes from the various diastereoisomeric series.