• 대한기계학회논문집
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• 제7권4호
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• pp.441-450
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• 1983

A reasonable J-resistance curve determination procedure is suggested by correcting the amount of overestimation in J-value whose effect becomes significant when crack grows. Experiments using compact tension specimens of an alloy steel (SCM4, K.S. Designation) are performed. The value of J estimated according to this procedure is compared with that as obtained from the method by Merkle and Corten. The conditions for J controlled crack growth proposed by Hutchinson and Paris are examined for the material used here. It appears that J resistance curve, which is independent of crack ratio can be obtained for those specimens satisfying the conditions of J controlled crack growth.

• Structural Engineering and Mechanics
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• 제61권2호
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• pp.275-282
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• 2017

The Fleck-Hutchinson theory on strain gradient plasticity (SGP), proposed in Adv. Appl Mech 33 (1997) 295, has recently been reformulated by adopting the strategy of decomposing the second order strain presented by Lam et al. in J Mech Pays Solids 51 (2003) 1477. The newly built SGP satisfies the non negativity of plastic dissipation, which is still an outstanding issue in other SGP theories. Furthermore, it explicitly shows how elastic strain gradients and corresponding elastic characteristic length scales come into play in general elastic-plastic loading histories. In this study, the relation between elastic length scales and plastic length scales is investigated by taking wire torsion as an example. It is concluded that the size effects arising when two sets of length scales are of the same order are essentially elastic instead of plastic.

• Journal of Plant Biology
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• 제28권3호
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• pp.207-216
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• 1985

Radial immunodiffusion, rocket immunoelectrophoresis, and Boyden procedure have been employed as quantitative analysis of pollen proteins in a systematic investigation of selected amentiferous plant taxa. Data presented here are continued and supplementary to the previous qualitative analysis of immunoprecipitin systems for the same purpose. Although the number of taxa tested has been limited, the serological evidence indicates that the Betulaceae has the greatest similarity to the Fagaceae, next to the Juglandaceae, the least to the Salicaceae, when antisera against Alnus hirsuta and Betula platyphylla var. japonica were used for tests. Within the Betulaceae Alnus and Betula show greatly similar affinities together, but less similar to the rest of genera: Carpinus, Carya and Corylus. When antisera against Quercus aliena, Q. dentata, and Q. glauca were used for tests, the following decreasing order to serological affinities was obtained: Quercus Alnus, Betula Carpinus, Carya, Corylus Juglans, Pterocarya Populus. Overall serological data come closer to supportint the classification systems of Cronquist, Takhtajan, and Hutchinson; but less of Thorne and Bessey. In addition this investigation indicated that pollen, with its high protein content, provided an excellent source of extractable antigens for serosystematic researches.

• Earthquakes and Structures
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• 제3권6호
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• pp.869-887
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• 2012

Ground motion scaling techniques are actively debated in the earthquake engineering community. Considerations such as what amplitude, over what period range and to what target spectrum are amongst the questions of practical importance. In this paper, the effect of various ground motion scaling approaches are explored using three reinforced concrete prototypical building models of 8, 12 and 20 stories designed to respond nonlinearly under a design level earthquake event in the seismically active Southern California region. Twenty-one recorded earthquake motions are selected using a probabilistic seismic hazard analysis and subsequently scaled using four different strategies. These motions are subsequently compared to spectrally compatible motions. The nonlinear response of a planar frameidealized building is evaluated in terms of plasticity distribution, floor level acceleration and uncorrelated acceleration amplification ratio distributions; and interstory drift distributions. The most pronounced response variability observed in association with the scaling method is the extent of higher mode participation in the nonlinear demands.

• Structural Engineering and Mechanics
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• 제5권1호
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• pp.51-58
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• 1997

The influence of bi-directional earthquake-induced loading on eccentric (plan-asymmetric) building systems has been investigated. In the first part of the study, comparisons have been made with equivalent results from uni-directional studies. The results are important in developing analytical models appropriate to the formulation of design recommendations. It is concluded that for valid comparisons, both perpendicular horizontal earthquake components must be considered when using models with transversely-orientated elements. In the second part of the study, an assessment has been made of a simplified, unidirectional (lateral) design approach. For stiffness-eccentric systems, the latter approach gives accurate and reasonably conservative estimates of the critical flexible-edge deformation, but may under estimate the stiff-edge element ductility demand by a factor of two in the short-period range.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.36-41
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• 2004

A method to measure the interfacial toughness of film/substrate by nanoindenter is proposed. As the thickness of the film decreases, the measurement of the interfacial toughness requires the more sophisticated equipment such as nanoindenter. In this study, the nanoindenter is applied to the substrate near the interface of film/substrate in the direction perpendicular to the normal of the interface, causing the cohesive fracture of the substrate, followed by the interfacial cracking. The specimen of Cu($0.56 {\mu}m$)/Si(530 ${\mu}$) are made by sputtering the copper onto the silicon wafer. By scratching the copper surface, we can make the easy interfacial cracking during the nanoindentation. It is found that the averaged values of the interfacial toughness of the Cu/Si is $0.664{\pm}0.3\;J/m^2$ . The phase angle of the specimen in this study is ${\psi}{\simeq}-36.8^{\circ}$, computed by the method of Suo and Hutchinson.[1]

• 대한예방의학회:학술대회논문집
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• 대한예방의학회 1994년도 교수 연수회(역학)
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• pp.324-331
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• 1994

To promote the inclusion of quality of life (QOL) end-points In clinical research on cancer, the National Cancer Institute (USA) sponsored a workshop on QOL assessment In cancer clinical trials In July, 1990. Experts In clinical trials and QOL research formed four working groups to Identify current areas of cancer treatment In which QOL end-points are most Important; to discuss methodologic problems In QOL assessment; to address common problems In Implementing clinical studies with QOL end-points; and to consider statistical Issues In design, Implementation, and data analysis. Recommendations made by the working groups are summarized in this paper.

• Structural Engineering and Mechanics
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• 제3권3호
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• pp.255-272
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• 1995

The paper considers aspects of the energy dissipation response of selected realistic forms of torsionally balanced and torsionally unbalanced building systems, responding to an ensemble of strong-motion earthquake records. Focus is placed on the proportion of the input seismic energy which is dissipated hysteretically, and the distribution of this energy amongst the various lateral load-resisting structural elements. Systems considered comprise those in which torsional effects are discounted in the design, and systems designed for torsion by typical code-defined procedures as incorporated in the New Zealand seismic standard. It is concluded that torsional response has a fundamentally significant influence on the energy dissipation demand of the critical edge elements, and that therefore the allocation of appropriate levels of yielding strength to these elements is a paramount design consideration. Finally, it is suggested that energy-based response parameters be developed in order to assist evaluations of the effectiveness of code torsional provisions in controlling damage to key structural elements in severe earthquakes.

• 대한수학회지
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• 제60권2호
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• pp.255-271
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• 2023

In this paper, we deal with random attractors for dynamical systems forced by a deterministic noise. These kind of systems are modeled as skew products where the dynamics of the forcing process are described by the base transformation. Here, we consider skew products over the Bernoulli shift with the unit interval fiber. We study the geometric structure of maximal attractors, the orbit stability and stability of mixing of these skew products under random perturbations of the fiber maps. We show that there exists an open set U in the space of such skew products so that any skew product belonging to this set admits an attractor which is either a continuous invariant graph or a bony graph attractor. These skew products have negative fiber Lyapunov exponents and their fiber maps are non-uniformly contracting, hence the non-uniform contraction rates are measured by Lyapnnov exponents. Furthermore, each skew product of U admits an invariant ergodic measure whose support is contained in that attractor. Additionally, we show that the invariant measure for the perturbed system is continuous in the Hutchinson metric.

• Tuberculosis and Respiratory Diseases
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• 제42권3호
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• pp.407-412
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• 1995

저자들은 호흡곤란을 주소로 내원하여 폐 침범 소견과 함께 피부변화를 동반한 전형적인 골 침범 소견을 보인 유육종증 1예를 경험하였으므로 문헌 고찰과 함께 보고하는 바이다.