• Advances in nano research
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• 제15권6호
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• pp.579-585
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• 2023

This research delves into the intricate dynamics of the flight response exhibited by a golf ball that incorporates nanoparticles with the goal of enhancing its overall quality. The golf ball is meticulously modeled utilizing beam elements, and the impact of nanoparticles is intricately captured through the application of the Halpin-Tsai theory. Employing a numerical solution, the study thoroughly explores the flight response of the golf ball, taking into account the nuanced effects of the embedded nanoparticles. By scrutinizing the aerodynamic characteristics through advanced simulations, this investigation aims to provide valuable insights that could potentially revolutionize the design and performance of golf equipment, offering a pathway towards superior quality and enhanced functionality in the realm of golf ball technology. Results show that increase in the volume percent of nanoparticles, improves the flight response of the golf ball.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.291-294
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• 2003

Ball indentation tests have been used to estimate the mechanical properties of materials by some investigators. In this study, load-depth curves from ball indentation tests have been analysed using the geometric conditions of ball indentation. Series of numerical calculations and experimental results showed that those curves could be simplified by linear functions. After linearizing the indentation curves, the estimation process of the flow properties became straight forward and the scatter of results could be drastically reduced.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.968-971
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• 1996

In this paper, feedback controller is designed for ball-beam system using genetic algorithms. A genetic algorithms are implemented for optimizing gain parameters of feedback controller. We can find optimal point in multi-dimensional search space by using genetic algorithms. Performance of controller is tested by simulation of ball-beam system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.350.2-350
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• 2002

The purpose of this study was to present the possible use of a new standard impactor, the rubber ball (so-called, impact ball), and to assess its evaluation method as fur heavy-weight impact in multi-story residential buildings. Several experiments were carried out to investigate the effect of the impactor on noise propagation in reinforced concrete buildings. Then, the noise from the impact ball was psychoacoustically evaluated. (omitted)

• Tribology and Lubricants
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• 제10권1호
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• pp.62-68
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• 1994

The analysis of statically indeterminate bearing-shaft system was investigated. The moment loads and misalignment angles which were induced in the ball bearings were determined, and the influence of span length of this system on the moment loads and fatigue lives was identified. The sliding and spinning speeds between balls and raceways which affected the performance of ball bearing evaluated. The equation to estimate the cage speed of ball bearing under moment loads was proposed. This equation had been verified by the test results of measuring of cage speed, which was useful to the prediction of ball bearing under moment loads.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2001년도 하계 학술대회 논문집(KISPS SUMMER CONFERENCE 2001
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• pp.125-128
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• 2001

In this paper, We proposed the nonlinear controller and observer design for a ball and beam system. Unfortunately, for the ball and beam system, the control coefficient is zero whenever the angular velocity or ball position are zero. Therefore, the relative degree of the ball and beam system is not well defined. The presented the nonlinear controller and observer design is based on the approximation input-output feedback linearization. And we verified that the proposed nonlinear controller and observer scheme is the feasible through a computer simulation.

• 시멘트
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• 통권60호
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• pp.47-56
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• 1975

ball mill로 최적의 능률을 달성하고 생산의 최대 Blaine을 얻기 위하여 ball을 최적으로 배열 선택하여야 한다. 이 논문에서는 분쇄기 직경과 분쇄도를 고려하여 피분쇄 물질의 입도에 따르는 최적의 ball size 계산법이 전개되었다. 나아가 분쇄물의 Blaine으로부터 입도 계산에 대한 단순한 관계가 명시되었다. Blaine은 분쇄기의 길이를 직선적으로 증가시키기 때문에 chamber의 길이와 수 그리고 필요한 구의 직경이 graph의 방법으로 쉽게 규정된다. 보다 큰 구의 사용으로 손해는 분쇄기의 원료(피분쇄물)를 사전에 파쇄시킴으로써 제거될 수 있다. 그 발전 경향은 보다 작은 분쇄 매체(grinding media)의 사용에로 진전되었으며 그 이유는 다음과 같다. (1) 증대된 분쇄기 직경 (2) 피분쇄물의 사전 파쇄 (3) 분쇄 법칙에 대한 지식 향상

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2003년도 춘계학술대회 발표 논문집
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• pp.116-119
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• 2003

본 연구에서는 LCD 공정에 사용되는 ball spacer를 전해 연마(Electro-Polishing, EP) 처리된 스테인리스(stainless)관 내부에서 마찰대전으로 하전시켜 하전량을 측정하는 하전 메커니즘과 하전 특성을 관찰하였다. Ball spacer의 농도를 일정하게 하고, 유입하는 공기의 유량을 201pm, 301pm으로 변화시키면서 실험하였다. 유입되는 공기의 유량은 일정하게 하여 ball spacer의 농도를 분진공급장치(dust feeder)를 통해 변화시키면서 하전수를 측정하였다. 이 때 측정결과는 EP 처리된 스테인리스관에 유입되는 공기의 유량이 증가했을 때, 하전이 더 많이 되는 것을 보여주었다. 또한 일정한 공기의 유량에서 주입되는 ball spacer의 농도가 증가했을 때 입자당 하전수가 증가하였다.

• 한국운동역학회지
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• 제14권3호
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• pp.191-202
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• 2004

The batting performance in baseball is a repetitive movement. In order to make the stabilization of posture and the efficient shift of body weight, both the range of stance and stride are important. The previous studies explained that the consistent stride which included the amount of time, stance, and direction were needed. However, the batting performance is frequently changed according to the several speed of ball. Therefore, this study was to analyze the reaction time, the range of stance, the change of stride, and the change of GRF during the batting movement in three kinds of ball speed (120km/h, 130km/h, & 140km/h). Seven elite players are participated in this study. 1. The reaction time of the stride phase was short whereas the time of the swing phase was long according to the increasing ball speed. 2. The range of the stance was wide and the mediolateral direction of the stride was decreased according to the increasing ball speed. 3. In the three kinds of ball speed, the change of body weight was transferred to the center, the rear foot, and the front foot directions. The ball speed of 130km/h showed the high frequency of the suitable batting. At this ball speed, the movement of the body weight was shifted smoothly and the value of the Ground Reaction Force was large enough.

• 한국수소및신에너지학회논문집
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• 제17권4호
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• pp.418-424
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• 2006

In order to improve the activation properties of the $AB_2$ type hydrogen storage alloys for Ni-MH battery, the alloy surface was modified by employing high energy ball milling. The $Zr_{0.54}Ti_{0.45}V_{0.54}Ni_{0.87}Cr_{0.15}Co_{0.21}Mn_{0.24}$ alloy powder was ball milled for various period by using the high energy ball mill. As the ball milling time increased, activation of the $AB_2$ type composite powder electrodes were enhanced regardless of additives. When the ball milling time was small discharge capacities of the $AB_2$ type composite powder electrodes increased with the milling time. On the other hand for large milling time it decreased with increasing milling time. The maximum discharge capacity was obtained by ball milling for 3-4 min.