• International Journal of Concrete Structures and Materials
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• v.4 no.1
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• pp.37-43
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• 2010

Theoretical models based on modern interpretations of the morphology and interactions of cement hydration products are developed for prediction of the mechanical properties of hydrated cement paste (hcp). The models are based on the emerging nanostructural vision of calcium silicate hydrate (C-S-H) morphology, and account for the intermolecular interactions between nano-scale calcium C-S-H particles. The models also incorporate the effects of capillary porosity and microcracking within hydrated cement paste. The intrinsic modulus of elasticity and tensile strength of hydrated cement paste are determined based on intermolecular interactions between C-S-H nano-particles. Modeling of fracture toughness indicates that frictional pull-out of the micro-scale calcium hydroxide (CH) platelets makes major contributions to the fracture energy of hcp. A tensile strength model was developed for hcp based on the linear elastic fracture mechanics theories. The predicted theoretical models are in reasonable agreements with empirical models developed based on the experimental performance of hcp.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.199-199
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• 2006

Microwave-irradiation has become a common heat source in organic chemistry in the last decade. In recent years, polymer chemists also discovered the advances of microwave heating that include fast and efficient heating as well as the homogeneous heat profile and the easy access to pressurized reaction conditions. In this contribution, we report our investigations on the cationic ring-opening polymerization of 2-oxazolines that lead to a tremendous acceleration from several days to several minutes polymerization time. In addition, the optimized microwave-assisted polymerization procedure was applied for the preparation of libraries of diblock and triblock copolymers that were used for the determination of structure-property relationships in poly(2-oxazoline)s.

• Journal of Korea Foundry Society
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• v.9 no.3
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• pp.228-236
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• 1989

The relationships between nodularity, tensile property and ultrasonic velocity were studied in ductile iron castings having similar matrix structure. Also, the effects of heat treatment and the number of graphite nodules on the ultrasonic velocity were investigated. The results were as follows 1. The ultrasonic velocity increased proportionally with increassing nodularity and tensile strength. 2. The ultrasonic velocity in annealed and normalized state decreased average 1.7% and 3.4% respectively than that in as cast state. 3. The ultrasonic velocity increased with increasing the number of graphite nodules. Therefore, ductile iron castings can be evaluated in the only case of castings having the same manufacturing history by ultrasonic velocity.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.189.1-189.1
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• 2003

4-(4-Methoxyphenyl)-2-aminothiazole and 3-(4-methoxyphenyl)-5-aminothiadiazole derivatives have been synthesized and evaluated as selective antagonists for human adenosine A$_3$ receptors. A methoxy group in the 4-position of the phenyl ring and N-acetyl or propionyl substitutions of the aminothiazole and aminothiadiazole templates displayed great increases of binding affinity and selectivity for human adenosine A$_3$ receptors. The most potent A$_3$ antagonist of the present series, N-［3-(4-methoxy-phenyl)-［1,2,4］thiadiazol-5-yl］-acetamide exhibiting a K$\_$i/ value of 0.79 nM at human adenosine A$_3$ receptors, showed antagonistic property in functional assay of cAMP biosynthesis involved in one of the signal transduction pathways of adenosine A$_3$ receptors. (omitted)

• Journal of applied mathematics & informatics
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• v.42 no.3
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• pp.471-481
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• 2024

In this paper, the concept of D-sets will be applied to create D-lindelöf spaces, a new type of topological space covering the property. This is performed by using a D-cover, which is a special type of cover. The primary purpose of this work is to introduce the principles and concepts of D-lindelöf spaces. We look into their properties as well as their relationships with other topological spaces. The basic relationship between D-lindelöf spaces and lindelöf spaces, as well as many other topological spaces, will be given and described, including D-compact, D-countably compact, and D-countably lindelöf spaces. Many novel theories, facts, and illustrative and counter-examples will be investigated. We will use several informative instances to explore certain of the features of the Cartesian product procedure across D-lindelöf spaces as well as additional spaces under more conditions.

• Journal of the Korean Society for Library and Information Science
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• v.54 no.3
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• pp.165-186
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• 2020

Although BIBFRAME is recognized as a new bibliographic standard that can replace the existing MARC structure, the vastness of the descriptive items shows many limitations to be applied in library communities. Thus this study proposed separating the descriptive levels of BIBFRAME as a way to enhance the applicability of BIBFRAME. The descriptive level of BIBFRAME was divided into three stages: core, standard, and detailed levels based on the bibliographic area of ISBD 2011. This separation was semantically implemented using RDF/RDFS syntax. The levels of description in BIBFRAME was defined as Class Granularity and Class Element, and the Property Relation was defined for the linkage between the Classes defined and the BIBFRAME. By applying this syntactic structure, the relationships between the BIBFRAME descriptive items separated by each descriptive level could be linked with each other. This approach is expected to ensure applicability in the creation and sharing of bibliographic data using BIBFRAME.

• Journal of Korean Library and Information Science Society
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• v.54 no.2
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• pp.1-22
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• 2023

In this study, we propose a plan to reflect LRM in various library-related standards or systems through analyzing the reflection of LRM in RDA. To this end, LRM and RDA 2020 were analyzed in terms of entities, relationships, attributes, and encoding schemes. First of all, for the mapping of entities, relationships, and attributes, all properties and relationships were extracted for each entity of RDA, LRM elements corresponding to each property and relationship were found and mapped, and encoding schemes were additionally compared. As a result, the things to consider in the standards and systems to which LRM is to be applied are: first, entities development considering the LRM hierarchy; second, new relation or shortcut path relation development; third, attributes expansion according to the entities considering the LRM hierarchical structure, and fourth, the development of various encoding scheme. Through this study, it will be possible to find an application plan using the application of RDA as a model in standards or systems to accept LRM.

• Journal of Industrial Technology
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• v.6
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• pp.33-38
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• 1986

The aim of this study is to find out the relationships between the microstructures of SM45C(AISI1045) steel and fatigue crack propagation behaviour. Three microstructures such as (i) as received (fully annealed). (ii) water quenched and tempered, and (iii) oil quenched and tempered were used for fundamental mechanical testing and fatigue crack proagation test. The microstructures of (ii) and (iii) showed superior in tensile strength to (i). Resistance against fatigue crack propagation was higher in structure (i), while tensile properties were better in structures (ii) and (iii). It is believed due to that the enhancement of roughness of fracture surface obsered in structure (i) increases ${\Delta}Kth$ and lowers fatigue crack growth rate. However it does not necessarily mean the quenched and tempered structures (ii) and (iii) are undesirable for the engineering component because fatigue limit in low cycle test appears usually higher in the microstructures of higher strength.

• BMB Reports
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• v.29 no.6
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• pp.545-548
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• 1996

CA(1-8)ME(1-12), the CA-ME hybrid peptide of the amino terminal segments of cecropin A (CA) and melittin (ME), has been reported to have a broad spectrum and improved potency without a hemolytic property. In order to obtain new synthetic peptides with powerful antibacterial activity without hemolytic activity, several hybrid peptides were designed from the sequences of CA, ME, magainin 2, bombinin and lactoferricin. All hybrid peptides were constructed to form an amphipathically basic-flexible-hydrophobic structure and synthesized by the solid phase method. Their hemolytic activities against human red blood cells and antibacterial activities against both Gram-positive and Gram-negative bacteria were detennined. CA(1-8)MA(1-12), CA(1-8)BO(1-12), MA(10-17)ME(1-12) and LF(20-29)ME(1-12) showed comparable activities with broad spectra against both Gram-positive and Gram-negative bacteria relative to CA(1-8)ME(1-12) but without hemolytic properties. These hybrid peptides, therefore, could be useful as model peptides to design a novel peptide with improved antibacterial activity and study on structure-activity relationships of antimicrobial peptides.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.1 s.71
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• pp.63-71
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• 2006

This study presents the effective stiffness-based optimal technique to control Quantitatively lateral drift for shear wall-frame structure system using sensitivity analysis. To this end, the element stiffness matrices are constituted to solve the compatibility problem of displacement degree of freedom between the frame and shear wall. Also, lateral drift constraint to introduce the approximation concept that can preserve the generality of the mathematical programming and can effectively solve the large scaled problems is established. And, the section property relationships for shear wall and frame members are considered in order to reduce the number of design variables and differentiate easily the stiffness matrices. Specifically, constant-shape assumption which is uniformly varying in size during optimal process is applied in frame structure. The thickness or length of shear wall can be changed depending on user's intent. Two types of 20 story shear wall-frame structure system are presented to illustrate the features of the stiffness-based optimal design technique.