• Explosives and Blasting
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• v.41 no.3
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• pp.1-12
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• 2023

A basic assessment of techniques to mitigate the risk of blast shock waves from proximity explosions was conducted. Common existing techniques include using mitigant materials to form barriers around the explosive or in the direction of propagation of the shock wave. Various explosive energy dissipation mechanisms have been proposed, and research on blast shock wave mitigation utilizing impedance differences has drawn considerable interest. In this study, shear thickening fluid (STF) was applied as a blast mitigation material to evaluate the effectiveness of STF mitigation material on explosion shock wave mitigation through explosion experiments and numerical analysis. As a result, the effectiveness of the STF mitigant material in reducing the explosion shock pressure was verified.

• Proceedings of the Korean Fiber Society Conference
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• 1998.04a
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• pp.144-147
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• 1998

다양한 변형 양식에 대한 고분자 물질의 응답특성을 예측하기 위해서는 완화 스펙트럼 H(λ) 또는 선형 완화 탄성율 G(t)를 결정하여야 한다. 완화 스펙트럼은 연속 완화 스펙트럼과 불연속 완화 스펙트럼(혹은 이산 완화 스펙트럼)으로 구분되며, 완화 스펙트럼과 완화 탄성율을 동적 점탄성으로부터 계산할 수 있는 여러 가지 방법들이 많은 연구자들에 의해 수행되어 왔다.(중략)

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.160-165
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• 1999

Agarose gels can be used as reference standards for the measurement of fluid properties in porous media because the relaxation properties of the gel reference standard and those of the fluid in porous media can be closely matched. The use of reference standard to determine porosity and saturation is discussed and the requirements for gel NMR properties given. The relaxtion times of agarose gels measured at 2.0 Tesla are illustrated as a function of agarose and paramagnetic impurity ($CuSO_4$) concentrations. This work shows an empirical result between agarose gel composition and gel relaxtion times. The average value for the porosity distribution is 17.7%, which compares well with the value calculated with the gravimetric analysis. Finally, two phase immiscible displacement using agarose gels as a reference standard was performed. The saturation profiles appear to be consistent with what one might calculate for a one-dimensional displacement in a uniform porous media.

• Journal of Sensor Science and Technology
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• v.2 no.1
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• pp.65-74
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• 1993

A miniature size electrostatic induction motor has been fabricated and studied with emphasis on the role of the surface resistivity, the relative dielectric constant and the charge relaxation time constant of the rotor surface materials and the rotor liner materials, which, however, control the surface charge induction and relaxation on the rotor material surface and the field intensity between the rotor and the stator of the motor. It is found that the surface resistivity and/or the relative dielectric constant, and the charge relaxation time constant of the rotor surface material enfluenced significantly to motor speed controlled by the surface charge induction and relaxation on the rotor surface depending on the applied voltage and/or frequency changing. The resistivity of the rotor liner material is also found to be effected to the motor speed greatly by control of the field intensity between the rotor and the stator and of the surface charge distribution of the induced charge on the rotor. As a result, a maximum no load rotor speed of the motor tested was about 5500 rpm at the applied voltage of 4.5 kV and the frequency of 220 Hz for the case of the rotor surface material of $BaTiO_{3}$ 80% in the resin binder layered on the copper-foil rotor liner material.

• Elastomers and Composites
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• v.45 no.4
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• pp.250-255
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• 2010

From the three element non-Newtonian model of one non-Newtonian viscoelastic Maxwell elements and a elastic spring, the stress relaxation equation was derived. The various model parameters of this equation were evaluated by appling the experimental results of stress relaxation to the stress relaxation equation. The theoretical curves calculated from this model parameters agreed with the experimental stress relaxation curves. From the parameters of nonlinear viscoelastic model, the hole volume, fine structure, viscoelastic properties and mechanical properties of polymer fibers were studied. The experiments of stress relaxation were carried out using the tensile tester with the solvent chamber. The stress relaxation curves of the two types polyacrylonitrile-polyvinylchloride copolymer and another two types PVC monofilament fibers were obtained in air and water of various temperatures.

• Proceedings of the Korean Fiber Society Conference
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• 1998.04a
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• pp.148-151
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• 1998

대부분의 고분자 가공공정에 있어서 가공원액(고분자 액체 또는 용융물)은 선형영역을 벗어나는 큰 크기의 변형을 받으므로 기존의 선형 점탄성 이론으로는 그 공정해석이 불가능하다. 그러므로 대변형하에서 고분자 물질의 비선형 거동 해석은 실제 공정과 관련된 공학적인 관점에서 볼 때 매우 중요한 과제라고 할 수 있다. 특히 응력완화 실험은 점탄성 액체의 비선형 완화 거동을 고찰하고 지금까지 제시된 각종 구성방정식을 평가하는데 유용하다.(중략)

• Proceedings of the Korean Magnestics Society Conference
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• 2007.12a
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• pp.220-221
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• 2007

• Korean Journal of Plant Resources
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• v.26 no.1
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• pp.103-110
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• 2013

Lacquer has traditionally been used to varnish. Many reports have revealed that lacquer has anti-microbical, anti-cancer, and anti-inflammatory activities. However, urushiol and their derivatives were known as an allergen. Therefore, we expected that lacquer will be used as a good health-food source if its side effect was solved. Here we analyzed their allergy induced constituents by using the GC/MS and evaluated comparative concentration of lacquer, puerariae radix and their mixture extracts. Our results showed that lacquer extract has allergenic compounds and mixture extract with puerariae radix has relatively lower amount. However, lacquer/puerariae mixture extract has strong anti-allergenic effects on the RBL-2H3 cell and puerariae extract was blocked allergenic effect caused by allergenic constituents contained in lacquer.

• Journal of the Korean Applied Science and Technology
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• v.36 no.4
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• pp.1050-1059
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• 2019

The self diffusion, hole volume, and flow thermodynamic parameters of polyamide fibers were calculated from rheological parameters and crystallite size in order to study of flow segments in amorphous region. The stress relaxation of polyamide filament fibers were carried out in air and various solvents at various temperatures using the tensile tester with the solvent chamber. The rheological parameters were obtained by applying the experimental stress relaxation curves to the theoretical equation of the Ree-Eyring and Maxwell non-Newtonian model. It was observed that the rheological parameters of these polyamide filament fibers are directly related to the relaxation spectra, self diffusion, viscosities, and activation energies of flow segments.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1992.05a
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• pp.51-51
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• 1992

신의 약품을 개발하는 과정에서 안전성의 평가는 신약후보물질의 인체에 대한 유해의 정도를 파악하고 신약후보물질들의 독성을 초기에 검색하여 의약품으로써의 개발여부를 결정하는데 기여함으로써 개발연구에 소요되는 시간 및 경제적 낭비를 줄일 수 있는 매우 중요하고도 필수적인 단계이다. 또한 생체독성억제물질의 개발에 관한 연구는 다양한 연구기법을 활용하여 각종 생체이물에 의한 생체독성의 발현을 억제하거나 발현된 독성반응을 완화, 경감시키는 물질이나 기법을 탐색함으로써 신약후보물질의 창출에 기여 할 수 있을 것으로 기대되고 있다. 이와 같은 관점에서 안전성 연구팀은 그 연구분야를 크게 특수독성검색기술 개발연구와 생체독성억제물질 개발연구 분야로 대별하고 1)발암조기검색법 개발연구 2)독성물질 대사효소계에 관한 연구 3)유전자 손상억제물질개발연구 4)간독성 억제물질 개발연구 5)신장독성 억제물질 개발연구 6)면역독성 억제물질 개발연구 7)대사 및 내분비계 독성억제물질 개발연구 8)순환기계독성 억제물질 개발연구 등 총 8개의 세부과제와 안전성평가제도의 국제화를 위한 제도 및 기준에 관한 연구를 수행하고 있는바 이들의 연구목표와 내용 그리고 1차년도의 연구결과를 개괄적으로 소개함으로써 본 과제가 포괄하는 제반 안전성연구내용에 대한 이해를 도모하고자 한다.