• Elastomers and Composites
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• 제38권1호
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• pp.27-37
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• 2003

This work presents a comparative study of the morphology and structure related properties of thermoplastic elastomer blends based on SEBS/PP/Oil and dynamically vulcanized EPDM/PP/Oil. A combination of ruthenium oxide staining and low voltage scanning electron microscopy (LVSEM) was found to be suitable for the study of morphology of these highly oil extended blends. h close analogy was found in the mechanical, thermal and rheological properties of the two systems made in an internal Brabender mixer and co-rotating turin screw extruder. The morphology of the blends, as made by the two techniques, was found to be significantly different. In the case of TPVs, the blonds made in the extruder had smaller EPDM domains and better tensile properties. In the case of SEBS, the blends made in the Brabender had more co-continuous phases and showed better tensile properties. Crystallization behavior of the isotactic polypropylene in the blends was found to be influenced by the type of rubber. Blends of SEBS/PP crystallized at a lower temperature than the TPVs. These differences were probably caused by differences in the nucleating ability of the two rubbers.

• BMB Reports
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• 제40권6호
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• pp.1095-1099
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• 2007

Endonuclease G (EndoG) is a mitochondrial non-specific nuclease that is highly conserved among the eukaryotes. Although the precise role of EndoG in mitochondria is not yet known, the enzyme is released from the mitochondria and digests nuclear DNA during apoptosis in mammalian cells. Schizosaccharomyces pombe has an EndoG homolog Pnu1p (previously named SpNuc1) that is produced as a precursor protein with a mitochondrial targeting sequence. During the sorting into mitochondria the signal sequence is cleaved to yield the functionally active endonuclease. From the analogy to EndoG, active extramitochondrial Pnu1p may trigger cell killing by degrading nuclear DNA. Here, we tested this possibility by expressing a truncated Pnu1p lacking the signal sequence in the extramitochondrial region of pnu1-deleted cells. The truncated Pnu1p was localized in the cytosol and nuclei of yeast cells. And ectopic expression of active Pnu1p led to cell death with fragmentation of nuclear DNA. This suggests that the Pnu1p is possibly involved in a certain type of yeast cell death via DNA fragmentation. Although expression of human Bak in S. pombe was lethal, Pnu1p nuclease is not necessary for hBak-induced cell death.

• Smart Structures and Systems
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• 제3권2호
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• pp.147-172
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• 2007

The present paper is concerned with the design of distributed sensors and actuators. Strain type sensors and actuators are considered with their intensity continuously distributed throughout a continuous structure. The sensors measure a weighted average of the strain tensor. As a starting point for their design we introduce the concept of collocated sensors and actuators as well as the so-called natural output. Then we utilize the principle of virtual work for an auxiliary quasi-static problem to assign a mechanical interpretation to the natural output of the sensors to be designed. Therefore, we take the virtual displacements in the principle of virtual work as that part of the displacement in the original problem, which characterizes the deviation from a desired one. We introduce different kinds of distributed sensors, each of them with a mechanical interpretation other than a weighted average of the strain tensor. Additionally, we assign a mechanical interpretation to the collocated actuators as well; for that purpose we use an extended body force analogy. The sensors and actuators are applied to solve the displacement tracking problem for continuous structures; i.e., the problem of enforcing a desired displacement field. We discuss feed forward and feed back control. In the case of feed back control we show that a PD controller can stabilize the continuous system. Finally, a numerical example is presented. A desired deflection of a clamped-clamped beam is tracked by means of feed forward control, feed back control and a combination of the two.

• 한국자기학회지
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• 제5권5호
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• pp.753-757
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• 1995

Systematic studies on the crystal structure and magnetic properties of light rare earth element(RE) compounds with Pb, $REPb_{2}$, have been carried out. Their crystal structure has been identified to be a $MoSi_{2}$-type. The values of the effective magnetic moment for $CePb_{2},\;PrPb_{2}\;and\;NdPb_{2}$ are respectively very close to the theoretical values of $RE^{3+}$. These three compounds are antiferromagnetic and exhibit a metamagnetic transition. The magnitude of the Neel temperature is proportional to two-thirds of the de Gennes factor. The magnetic entropy change for $NdPb_{2}$ is contrast to the value for $CePb_{2}$ heavy-fermion compound, comparable to the theoretical value. The magnetic contribution to the temperature dependence of resistivity for $PrPb_{2}$ is given by a form of -lnT in a wide temperature range, implying the Kondo system in analogy with $Cepb_{2}$.

• 산업기술연구
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• 제37권1호
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• pp.32-36
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• 2017

In this study, as part of a research on the development of economical high-performance concrete with high strength and high quality, the physical properties of high-performance concrete were analyzed by substituting a certain amount of low-cost domestic silica fume exempted from the re-importation type distribution structure of the domestic production and the existing high-priced silica fume distribution structure. Performing tests to identify the physical properties of the fresh and hardened concrete and durability analogy of the concrete which use low-cost domestic silica fume and imported silica fume, the chloride ion penetration resistance test result showed that the strength difference between the low-cost silica fume and the imported silica fume is not big but the strength of the low-cost silica fume was measured higher than the imported silica fume. The chloride ion penetration resistance of all variables was measured as "very low". Since the low-cost domestic silica fume can be used as a high-performance admixture of concrete, the results suggest that it is possible to produce a more economical high-performance concrete.

• 한국과학교육학회지
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• 제24권1호
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• pp.146-156
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• 2004

The purpose of this study is to look at the use of heuristics when a sixth grader solves a problem. Two research questions have been formulated: The similarities and differences in the use of heuristics when a student solves two problems that are science-knowledge-based and not science-knowledge-based, and the different types of prompts. A male sixth grade student participated in this study. All of the information for the study was collected in three interviews. The interviews began with observing the student's solving problems. The student was asked how and why he solved problem that way. There were some interactions between the researcher and the student during the interview procedures. As results of this study, eight general heuristics were used in both solutions: Check examples for support of an idea: check examples for exceptions to an idea: restate the problem: compare to known examples or patterns: make a hypothesis; check the relevance of other information present; use analogy: and recognize patterns/similarity. There seemed to be more similarities than differences in the type of general heuristic that were used in the two problem solutions. The student was systematic and consistent in his use of the general use of heuristics. Five types of interviewer prompts were detected in the two problem solutions, directional cues, modeling, clarity, problem posing, metacognition and validation.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 후기학술대회논문집
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• pp.244-245
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• 2005

This paper presents the heat transfer and pressure drop characteristics during cooling process of carbon dioxide in a horizontal tube. The test section is a tube in tube type heat exchanger with refrigerant flowing in the inner tube and water flowing in the annulus. It was made of a stainless steel tube with the inner diameter of 7.75 [mm], the outer 2 diameter of 9.53 [mm] and length of 6000 [mm]. The refrigerant mass fluxes were $200{\sim}400$ [kg/$m^2s$] and the average pressure varied from 7.5 [MPa] to 10.0 [MPa]. The main results were summarized as follows The heat transfer coefficient of supercritical $CO_2$ increases in decrease of the gas cooler pressure. And the heat transfer coefficient increases with respect to the increase of the refrigerant mass flux. Among some correlations proposed in a transcritical region, Bringer-Smith's correlation has some analogy with experimental results. The pressure drop decreases in increase of the gas cooler pressure and increases with respect to increase the refrigerant mass flux.

• ETRI Journal
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• 제38권2호
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• pp.376-386
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• 2016

Currently, web applications are gaining in prevalence. In a web application, an input may not be appropriately validated, making the web application susceptible to cross-site scripting (XSS), which poses serious security problems for Internet users and websites to whom such trusted web pages belong. A taint inference is a type of information flow analysis technique that is useful in detecting XSS on the client side. However, in existing techniques, two current practical issues have yet to be handled properly. One is URL rewriting, which transforms a standard URL into a clearer and more manageable form. Another is HTML sanitization, which filters an input against blacklists or whitelists of HTML tags or attributes. In this paper, we make an analogy between the taint inference problem and the molecule sequence alignment problem in bioinformatics, and transfer two techniques related to the latter over to the former to solve the aforementioned yet-to-be-handled-properly practical issues. In particular, in our method, URL rewriting is addressed using local sequence alignment and HTML sanitization is modeled by introducing a removal gap penalty. Empirical results demonstrate the effectiveness and efficiency of our method.

• 호남수학학술지
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• 제8권1호
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• pp.1-19
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• 1986

We show that a (possibly unbounded) linear operator, T, is scalar on the real line (spectral operator of scalar type, with real spectrum) if and only if (iT) generates a uniformly bounded semigroup and $(1-iT)(1+iT)^{-1}$ is scalar on the unit circle. T is scalar on [0, $\infty$) if and only if T generates a uniformly bounded semigroup and $(1+T)^{-1}$ is scalar on [0,1). By analogy with these results, we define $C^0$-scalar, on the real line, or [0. $\infty$), for an unbounded operator. We show that a generator of a positive-definite group is $C^0$-scalar on the real line. and a generator of a completely monotone semigroup is $C^0$-scalar on [0, $\infty$). We give sufficient conditions for a closed operator, T, to generate a positive-definite group: the sequence < $\phi(T^{n}x)$ > $_{n=0}^{\infty}$ must equal the moments of a positive measure on the real line, for sufficiently many positive $\phi$ in $X^{*}$, x in X. If the measures are supported on [0, $\infty$), then T generates a completely monotone semigroup. On a reflexive Banach lattice, these conditions are also necessary, and are equivalent to T being scalar, with positive projection-valued measure. T generates a completely monotone semigroup if and only if T is positive and m-dispersive and generates a bounded holomorphic semigroup.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.311-318
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• 2013

The paper describes the prediction method for the unsteady flow field and the aeroacoustic noise of an small axial fan. The prediction method is comprised of various CFD conditions and acoustic analogy by using Ffowcs Williams-Hawkings equation. The diameter of tested axial fan is 170 mm and number of blade is 5. Virtual anechoic room which has same size with real one was used for CFD. URANS and LES models were used. For mesh dependence study, a different mesh type was tested and optimized mesh was selected. Calculation conditions were also studied such as time step and turbulence model for accurate noise analysis. In this paper, we got optimum analysis conditions and computational results. The unsteady pressure fluctuation at given 4 points were compared between the measured data and computational results. Also, the predicted acoustic spectrum at 3 given microphone points were compared with measured ones.