• Journal of the Korean Magnetics Society
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• v.14 no.2
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• pp.83-88
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• 2004

Magnetism of molecular nanomagnet, which attracted a lot of academic attention after the discovery of the macroscopic quantum tunneling of magnetism, is reviewed. Molecular nanomagnet is metal-organic material in which magnetic ions are regularly located in the organic skeleton. Also, the interaction between the molecules is very small and those molecules form macroscopic molecular crystal in which molecules are residing at the element points in the crystal. Molecular nanomagnets show a lot of interesting features, especially, equivalence of macroscopic magnetic properties and molecular magnetic properties. In this paper, research results on molecular nanomagnet with microscopic tool like NMR are reviewed mainly. The new method to observe the quantum tunneling of magnetization discovered in Mnl2-ac with NMR is shown and the research results on the microscopic aspects of the macroscopic quantum tunneling of magnetization using the new method are shown. Also, the physical aspect of the level crossing effect which has been reported originally with NMR in molecular nanomagnet is reviewed with experiment results. The research results on the molecular nanomagnets will reveal the important information about the limit of the miniaturization of magnetic memory units and give us the basic scientific knowledge which is needed for the application for the quantum computation. Moreover, academically, many quantum mechanical theories which have not been checked the validity can be checked with experiments.

• Journal of the Korean Wood Science and Technology
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• v.49 no.4
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• pp.360-370
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• 2021

For the purpose of finding new uses for Miscanthus sinensis var. purpurascens, this study first constructed boards with the particles of the plant and impregnated them with phenolic resin at resin impregnation rates of 30 ± 2%, 40 ± 2%, 50 ± 2%, and 60 ± 2%. The impregnated boards were then carbonized at the carbonization temperature of 800℃, after which their density and mechanical properties were examined according to the different resin impregnation rates. The results showed that density, flexural strength performance, Brinell hardness, and compressive strength increased as the resin impregnation rate increased, thus affecting the physical and mechanical properties of the ceramics made of M. sinensis var. purpurascens particles.

• Geotechnical Engineering
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• v.11 no.3
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• pp.113-122
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• 1995

The purposes of this study are to investigate the mechanical prospeities of the inter mediate soils through consolidation tests and triaxial compression shear tests. The intermediate soils used in this study are artificial soils which are composed of sea clay, sand and it's crushed component. The relationship between plastic index and mechanical prosperties (permeability and compressibility) is investigated through series of consoli dation tests. Strain hardening phenomenon under shearing is explored based on several overconsideration ratios and strain rates in undrained shear tests. To make a comparative study difference of drain condition and strain rate, drain shear tests are performed with overconsolidation ratio.

• Physical Therapy Korea
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• v.6 no.4
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• pp.36-42
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• 1999

본 연구의 목적은 운동제어/학습 또는 운동역학을 연구하는데 중요한 역할을 하는 근전도의 사용과 근전도와 등척성 수축력과의 관계에 나타나는 문제점과 제안점을 조사하는 것이다. 선행연구를 분석한 결과, 등척성 힘의 증가에 따른 근전도의 증가 관계가 선형적 모양으로 나타나지는 않았다. 또한, 선행연구에서 근전도와 등척성 힘 관계를 연구하는데 몇 가지 문제점들이 발견되었다. 이러한 문제점은 선행 연구실험들의 절차상에 차이가 나타났고, 근육의 생리학적인 또는 해부학적인 성질에서 문제점이 논의되었다. 결론적으로, 이러한 문제점들이 해결되지 않는 한 근전도와 등척성 수축력과의 관계는 불분명하게 남아있을 것이다.

• Science of Emotion and Sensibility
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• v.5 no.3
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• pp.39-46
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• 2002

The purpose of this study was to examine the effects of sensation and sensibility from the rusting sound of silk fabrics. The mechanical properties and sound parameters were measured after recording the rusting sounds of 7 silk fabrics. Then, their relationships were analyzed through the evaluation of subjective sensation and sensibility and found a regression model for the sensibility from the mechanical properties. The adjectives of the sensibility were grouped into four: Elegant, Active, Tough, Modern. Soft and flexible fabrics were related with LPT negatively and induced elegant sensibility. And fabrics of the smoother and less changable to shear direction were related with LPT and Δf, and positively, and occurred active sensibility. On the other hands, rough, bulky, thick, and heavy fabrics were related with ARC and Δf, and induced with tough or modern sensibilities. About the sensibilities according to each fabric, STN8 was the most elegant, STN8-S was the most active, and TWL16 and STN16-N were the toughest.

• The Journal of Engineering Geology
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• v.30 no.2
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• pp.161-173
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• 2020

This study is to examine the engineering characteristics of colunmar joints in Mudeugsan National Park, a global geopark. For these purposes, physical and mechanical properties of Mudeungsan Tuff, evaluation for the weathering degree of columnar joints, and crack behavior monitoring in columnar joints were conducted. The physical properties of Mudeungsan tuff were 1.02% for the average porosity, 0.38% for the average absorption, 2.69 g/㎤ for the average specific gravity, and 4,948 m/s for the average elastic wave velocity. Its mechanical properties were 337 MPa for the average uniaxial compressive strength, 68 GPa for the average elastic modulus, 0.29 for the average Poisson's ratio, 41.3 MPa for the average cohesion strength, and 62.8° for the average friction angle. the average rebound Q-value of the silver Schmidt hammer for the three columnar joint blocks at the Ipseok-dae was shown as 49.3. when this value is converted into uniaxial compressive strength, it becomes 70.5 MPa, which is about 21% of the uniaxial compression strength of Mudeungsan tuff. In addition, according to the results of crack monitoring measurements for the three columnar joint blocks at the Ipseok-dae, the crack behavior is less than 1 mm, so it is believed that its behavior in Ipseak-dae columnar joints has hardly occured to date.

• Journal of Radiation Protection and Research
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• v.17 no.1
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• pp.31-41
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• 1992

A study for the evaluation of selected filter media that need further characterization particularily in the context of alpha measurements of radon progeny has been carried out by investigating physical characteristics and using the alpha spectroscopy. Physical characteristics was investigated by electrostatic charging and mechanical strength of filters, and then pressure drop before and after sampling was tested. Alpha spectroscopy was used to analyze the energy spectra from the deposition of radon progeny into filters. The results of the assessment showed that the newer filter types do not have a great advantage over the 'old standard' Millipore type AA. But Metricel DM-800 is recommended for those situations where electrostatic charging is a problem. Also this method will be used more effective for the evaluation of new developing filters in future.

• Tunnel and Underground Space
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• v.25 no.1
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• pp.24-36
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• 2015

The Geochang granite widely used in construction works is one of the most popular dimension stones in Korea. In order to evaluate the physical properties of rock, a lot of laboratory tests for the Geochang granite were conducted to find unit weight, absorption ratio, P wave velocity, S wave velocity, uniaxial compressive strength, Young's modulus, Poisson's ratio, tensile strength, cohesion, friction angle and point load strength index. The uniaxial compressive strength of the Geochang granite was 19.5 times tensile strength and also 8.6 times cohesion, besides P wave velocity was 1.5 times S wave velocity. Correlation analyses were also conducted to find the correlation among 11 different physical properties, where the uniaxial compressive strength showed Pearson correlation coefficient of more than 0.8 with Poisson's ratio, point load strength index and Young's modulus, respectively. Regression analyses were finally conducted by means of both linear and multiple analysis and the brief results including coefficient of determination of more than 0.7 were presented.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.02a
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• pp.315-320
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• 2003

식품의 가공 분야뿐만 아니라 제약 공정 등의 생물산업 분야에서는 유변학(Rheology)이 차지하고 있는 위치는 매우 중요하며 물질의 유변물성을 정확히 파악하지 않고서는 정밀도를 요하는 가공 공정을 이룰 수 없어 우수한 제품을 생산하기 어렵다. 특히 작품 압출 성형분야에서 생물고분자(biopolymer) 원료의 유변 물성은 압출 성형시 중요한 역학을 하며 더 좋은 압출 성형 장치의 설계와 압출 공정의 제어를 위해서는 원료에 패한 물리적 성질의 이해와 압출 성형 장치 내에서 일어나는 변화를 이해해야 한다. (중략)

• Science of Emotion and Sensibility
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• v.9 no.1
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• pp.39-48
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• 2006

This study was carried out to investigate sound sensation of Korean traditional silk fabrics with similar sound pressure levels (SPL) and to identify secondary physical factors excluding SPL which determine sound sensation of the fabrics. Sounds of the silk fabrics tended to be perceived differently from one another as for some of sensation such as clearness ant roughness. They were felt more strongly in aspects of loudness, roughness, and highness than of softness, sharpness, clearness, and pleasantness. Subjective clearness, roughness, and highness were significantly correlated with some of sound parameters including roughness(z), ${\Delta}L,\;and\;{\Delta}f$. Especially, both of clearness and roughness which were varied among the fabrics were found as determined by ${\Delta}L$. This result means that ${\Delta}L$ as well as roughness(z) and ${\Delta}f$ could be utilized secondary to SPL in order to satisfy some of human sensibility for sound from traditional silk fabrics without variation of physical loudness.