• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.302-306
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• 1993

In this study, a new model for flexible disk grinding process will be proposed. A grinding mechanism with a grinding disk attached to the rubber platen has been introduced. Since the spinning axis is fixed and only the disk is deflected with respect to this axis, earlier model is not adequate to represent this proces. A new dynamic process model includes an assumption that the disk is deflected locally around the middle of its radial span between the spinning axis and the disk tip instead of several continuous deflection points along the radial span of the disk. Detailed kinematic analysis is proposed as for the removed portion during the process. Cutting force comonent and depth of cut profile trend is compared with the measured result.

• 한국재료학회지
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• 제27권1호
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• pp.43-47
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• 2017

E (Electric) -glass fibers are the most widely used glass fibers, taking up 90 % of the long glass fiber market. However, very few papers have appeared on the physical characteristics of E-glass fibers and how they depend on the fiberizing temperature of fiber spinning. Glass fiber was fabricated via continuous spinning process using bulk E-glass. In order to fabricate the E-glass specimen, raw materials were put into a Pt crucible and melted at $1550^{\circ}C$ for 2hrs; mixture was then annealed at $621{\pm}10^{\circ}C$ for 2hrs. The transmittance and adaptable temperature for spinning of the bulk marble glass were characterized using a UV-visible spectrometer and a viscometer. Continuous spinning was carried out using direct melting spinning equipment as a function of the fiberizing temperature in the range of $1175{\sim}1250^{\circ}C$, while the winder speed was fixed at 500 rpm. Subsequently we investigated the physical properties of the E-glass fiber. The average diameter of the synthesized glass fiber was measured by optical microscope. The mechanical properties of the fiber were confirmed using a UTM (universal materials testing machine); the maximum tensile strength was measured and found to be $1843{\pm}449MPa$ at $1225^{\circ}C$.

• 소성∙가공
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• 제6권6호
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• pp.517-526
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• 1997

The purpose of this study is to investigate changes in the wall thickness of tube sinking and working forces by the upper bound method and ABAQUS code. The independent variables are ; workpiece material, original wall thickness of tube, die angle, friction, and reduction of diameter. The results indicate that these five variables are factors of the increase in wall-thickness and working forces. Three variables, a inner tube wall angle and two angles of the velocity discontinuous surfaces, are optimized in this proposed velocity field by the upper bound method. In this method, we can estimate the working forces and final tube thicknesses similar to actual forming process. Optimum process variables which are obtained by upper bound method are used in ABAQUS pre-model.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.784-785
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• 2006

Co-based amorphous powder was produced by a new atomization process "Spinning Water Atomization Process (SWAP)", having rapid super-cooling rate. The composition of the alloys was ($(Co_{0.95}Fe_{0.05})_{1-x}Cr_x$)$_{75}Si_{15}B_{10}$ (x=0, 0.025, 0.05, 0.075). The powders became the amorphous state even if particle size was up to about $500{\mu}m$. The coercive force of powders was about 0.35 - 0.7 Oe. Furthermore, Co-based amorphous powder cores with glass binders were made by cold-pressing and sintering methods. The initial permeability of the core in the frequency range up to 100 kHz was about 110, and the core loss at 100 kHz for Bm = 0.1 T was $350kW/m^3$.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제11권12호
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• pp.489-498
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• 2022

최근 노동 집약적인 성격의 섬유 산업에서는 인공지능을 통해 섬유 방사 공정에 들어가는 비용을 줄이고 품질을 최적화하려고 시도 하고 있다. 그러나 섬유 방사 공정은 데이터 수집에 필요한 비용이 크고 체계적인 데이터 수집 및 처리 시스템이 부족하여 축적된 데이터양이 적다. 또 방사 목적에 따라 특정한 변수에만 변화를 준 데이터만을 우선으로 수집하여 데이터 불균형이 발생하며, 물성 측정 환경의 차이로 인해 동일 방사 조건에서 수집된 샘플 간에도 오차가 존재한다. 이러한 데이터 특성들을 고려하지 않고 인공지능 모델에 활용할 경우 과적합과 성능 저하 등의 문제가 발생할 수 있다. 따라서 본 논문에서는 방사 공정 데이터 특성을 고려한 이상치 처리 기법과 데이터 증강 기법을 제안한다. 그리고 이를 기존 이상치 처리 기법 및 데이터 증강 기법과 비교하여 제안한 기법이 방사 공정 데이터에 더 적합함을 보인다. 또 원본 데이터와 제안한 기법들로 처리된 데이터를 다양한 모델에 적용하여 비교함을 통해 제안한 기법들을 사용한 모델들이 그렇지 않은 모델들에 비해 인장 강신도 예측 모델의 성능이 개선됨을 보인다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2001년도 학술발표회 논문집(Proceedings of the Korean Textile Conference)
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• pp.261-264
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• 2001

• 소음진동
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• 제8권2호
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• pp.324-330
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• 1998

The forced vibration analysis of the outer-clamped spinnig annular disk with arbitrary in-plane is formulated to investigate the influence of non-uniform tension on the cutting accuracy of wafer cutting machine. The arbitrary in-plan force along the outer edge of an annular plate is expressed as a Fourier series. Galerkin method and modal superposition method are employed to obtain the forced responses under the static force and the impulse force in astationary coordinate. Through qualitative and quantitative analyses, it can be found that forced and impulse responses are sensitive to the non-uniformity of in-plane force, which can bring a bad effect to the accuracy of wafer cutting process. Also, in case of a spinning disk with non-uniform in-plane force, critical speed is required to define in a different way, compared with conventional definition in axi-symmetrical spinning disk.

• 한국가시화정보학회지
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• 제21권2호
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• pp.45-54
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• 2023

In the present study, we propose new type of a spinning disk reactor(SDR) with high performance and very convenient structure to make a large scale equipment from lab-scale than the conventional one. A split-disk experimental equipment, based on new type of spinning disk reactor, has been developed to generate an energy to break a bulk of injected gas into smaller gas bubble. Several cases of an experimental observation make it to confirm that a bulk of injecting gas could be continuously break into smaller bubbles. It shows the feasibility to make a scale-up of SDR by using the characteristic of Taylor-Proudman column in rotating flow. A theoretical study on single phase liquid flow is given to predict a liquid induced shear stress, which make the present study to be self-containment.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제26회 춘계학술대회논문집
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• pp.387-390
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• 2006

스피닝은 가장적은 가공력과 간단한 도구를 이용하여 소재를 변형시키는 방법중의 하나이다. 그리고 소재의 소성변형으로 인해 기계적 특성의 향상을 가져오는 공법이다. 이러한 스피닝 공법은 자동차, 항공, 군사 분야에서 중요한 부품의 생산에 적용되는 기술이다. 본 연구에서는 발사체 연료탱크의 돔형상에 스피닝 공법을 적용하여 제작함에 있어 롤러의 이송속도와 소재의 두께감소에 따른 성형력의 경향을 유한요소 해석을 이용하여 분석하였다.

• Korea-Australia Rheology Journal
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• 제13권1호
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• pp.1-12
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• 2001

This paper describes the application of our recently developed two-phase model for flow-induced crystallization (FIC) to the simulation of fiber spinning and film blowing. 1-D and 2-D simulations of fiber spinning include the combined effects of (FIC), viscoelasticity, filament cooling, air drag, inertia, surface tension and gravity and the process dynamics are modeled from the spinneret to the take-up roll device (below the freeze point). 1-D model fits and predictions are in very good quantitative agreement with high- and low-speed spinline data for both nylon and PET systems. Necking and the associated extensional softening are also predicted. Consistent with experimental observations, the 2-D model also predicts a skin-core structure at low and intermediate spin speeds, with the stress, chain extension and crystallinity being highest at the surface. Film blowing is simulated using a "quasi-cylindrical" approximation for the momentum equations, and simulations include the combined effects of flow-induced crystallization, viscoelasticity, and bubble cooling. The effects of inflation pressure, melt extrusion temperature and take-up ratio on the bubble shape are predicted to be in agreement with experimental observations, and the location of the frost line is predicted naturally as a consequence of flow-induced crystallization. An important feature of our FIC model is the ability to predict stresses at the freeze point in fiber spinning and the frost line in film blowing, both of which are related to the physical and mechanical properties of the final product.l product.