• 제목/요약/키워드: tilt angle

검색결과 629건 처리시간 0.028초

그루브수 증가에 따른 알루미늄 그루브 히트파이프의 성능향상에 관한 실험적 연구 (Experimental Study on the Performance Improvement of Aluminum Grooved Heat Pipe due to increased number of Grooves)

  • 홍진관;최상곤;김대성;정원복;변윤식;영권옥
    • 설비공학논문집
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    • 제13권6호
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    • pp.474-481
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    • 2001
  • Aluminum/Freon22 grooved hat pipes which have 26 axial grooves in a cross-section were manufactured and tested. The performance test was conducted by varying filling ratio and tilt angle. Operation limit, thermal resistance, overall heat transfer coefficient were investigated. The experimental result was compared with previous study which conducted in the case of a heat pipe with combined wick. The experimental result shows that thermal resistance of this heat pipe is twice smaller than that of the heat pipe with combined wick and operation limit is increased about 75%, comparing with that of heat pipe with combined wick.

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Organosiloxanes with molecular microrelief for liquid crystal alignment

  • Mazaeva, Vera G.;Belyaev, Victor V.;Timofeyev, Sergey N.;Min'ko, Anatoliy A.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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    • pp.948-950
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    • 2009
  • A few organosilicon compounds (OC) - both cyclic and linear siloxanes with different structure of the substituents - have been synthesized. Properties of the LC anchoring on OC films have been measured. The OC investigated provide the homogeneous planar alignment with LC tilt angle in the range from $0.7^{\circ}$ to $1.9^{\circ}$. An increase of the microrelief depth results in a small increase of the tilt angle. The azimuthal anchoring is better for the films of the OC without molecular microrelief or the OC comprising polar groups.

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3-Component RGB chip으로 구성된 LED 전구의 광학적 설계 (Optical design of an LED lamp composed of 3-Component RGB chips)

  • 강석훈;송상빈;권용석;여인선
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
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    • pp.197-199
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    • 2002
  • This paper describes the effects of chip arrangement configurations and the dimension of a reflecting cup upon the light output characteristics of a white lamp composed of RGB LED chips. As a result of simulation, the shorter distance between adjacent chips leads to a relative decrease in the light output efficiency due to inter-chip absorption of quanta, but rather uniform color mixing is expected. Among the factors of designing a reflecting cup it is the tilt angle of the cup wall that plays a determining role upon the variation of the light distribution. The light distribution shows a sudden change of pattern from Lambertian to Batwing at about $35^{\circ}{\sim}40^{\circ}$ of tilt angle in case of a silver-coated wall cup.

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공냉식 리튬 이온 배터리 팩의 열 성능 향상을 위한 내부 구조 최적화 (Internal Structure Optimization to enhance the Thermal Performance of an Air-cooled Lithium-ion Battery Pack)

  • ;조종래
    • 한국기계가공학회지
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    • 제20권12호
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    • pp.54-64
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    • 2021
  • Electric vehicles use lithium-ion battery packs as the power supply, where the batteries are connected in series or parallel. The temperature control of each battery is essential to ensure a consistent overall temperature. This study focused on reducing ohmic heating caused by batteries to realize a uniform battery temperature. The battery spacing was optimized to improve air cooling, and the tilt angle between the batteries was varied to optimize the internal structure of the batterypack. Simulations were performed to evaluate the effects of these parameters, and the results showed that the optimal scheme effectively achieved a uniform battery temperature under a constant power discharge. These findings can contribute to future research on cooling methods for battery packs.

인수분해된 광각 빔 전파기법 및 방향전환 거울 해석에의 응용 (A Factored Wide Angle Propagation Technique Applied to Turning Mirror Simulation)

  • Youngchul Chung
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1996년도 추계학술대회 논문집
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    • pp.135-138
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    • 1996
  • A wide angle propagation techinque is formulated through an expansion of the Holmholtz operator followed by a Pade expansion and factorization of the resulting polynomials. Its accuracy is checked through the successful modeling of integrated waveguide turning mirrors, indicating that 6-th order polynomial can handle as large as 55$^{\circ}$tilt angle very accurately.

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척추측만증 치료를 위한 다양한 중재의 적용-사례연구 (The Effect of Various Interventions on an Adult with Scoliosis)

  • 최운호
    • 대한정형도수물리치료학회지
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    • 제17권2호
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    • pp.57-63
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    • 2011
  • Background: To investigate the effect of various intervention application on idiopathic scoliosis patient. Methods: One 20-years-old female subject underwent various intervention 3 times per week for 7 weeks. Modality physical therapy, muscle energy technique, combined pelvic tilt exercise and self exercise was performed for 50minutes. Degree of pain, axial trunk rotation, Cobb's angle, kyphotic angle, lumbar lordotic angle, and sacral angle were measured. Results: The subject decreased in degree of pan, axial trunk rotation, Cobb's angle, thoracic kyphotic angle, lumbar lordotic angle and sacral angle. Conclusions: The various interventions for scoliosis patients are effective in the pain and the improvement of angle on radiograph. However, any method is difficult to determine effective interventions.

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개선된 블록기반 영상처리기법에 의한 실시간 이동물체 추적시스템 (Real-Time Moving Object Tracking System using Advanced Block Based Image Processing)

  • 김도환;최경주;이일병
    • 인지과학
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    • 제16권4호
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    • pp.333-349
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    • 2005
  • 본 논문에서는 인간의 시각처리 원리 및 블록기반 영상처리기법에 바탕을 둔 실시간 이동물체 추적시스템을 소개한다. 제안하는 실시간 아동물체 추적시스템은 인간의 망막이 갖고 있는 생물학적 메커니즘의 장점을 활용하기 위하여 광각렌즈를 장착한 CCD(Charge-Coupled Device) 카메라와 펜-틸트-줌(Pan-Tilt-Zoom) 카메라를 사용하여 줌인(zoom-in)과 줌아웃(zoom-out) 효과를 동시에 발생시킬 수 있도록 구성되었고, 추적의 오차를 줄이기 위하여 입력되는 영상을 개별 화소 단위가 아닌 여러 개의 블록으로 나누어 처리하는 방식을 채택하여 영상처리를 빠르게 함과 동시에 미세한 잡영도 제거하여 이동하는 물체를 실시간으로 효율적이고도 빠르게 추적한다. 제안하는 시스템의 성능을 확인하기 위해 여러가지 형태의 실험을 수행하였으며 분석 결과를 통해 제안하는 시스템이 미세한 잡영에 거의 방해를 받지 않으면서도 움직이는 물체를 빠르게 감지해서 펜-틸트-줌 카메라를 올바르게 제어함을 알 수 있었다.

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3 차원 동적 자세균형 훈련기기의 능동/수동 체간 기울임에 따른 근 활성도 비교 (The Assessment on Electromyography of Trunk Muscle according to Passive and Active Trunk Tilt Exercise of 3-D Dynamic Postural Balance Training System)

  • 신선혜;유미;정구영;유창호;김경;정호춘;권대규
    • 한국정밀공학회지
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    • 제30권3호
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    • pp.331-339
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    • 2013
  • The Interest in disease prevention and rehabilitation is increasing depending on increase of patients with spinal. This is being developed using the spine stabilization device is being studied. So far studies have only evaluated the effect on trunk stabilization exercises but analysis of human movement patterns for active movement and passive movement did not. We assessed the muscle activity of trunk and leg muscle during passive and active tilt mode on eight tilt directions at tilt angle of $30^{\circ}$ using 3-D dynamic postural balance training system. We performed experimental study on the muscular activities of trunk muscle about rectus abdominis, external obliques, latissimus dorsi, erector spinae, and leg muscle about rectus femoris, Biceps femoris, Tibialis Anterior, gastrocnemius. As a result, muscle activation was different depending on the direction of movement and pattern. The results indicate that various patterns of spinal stabilization exercise system could be applied to an effective training of chronic low back pain patients.

서브 마이크로 구조를 가진 실리콘 표면의 마찰 특성 연구 (Study on Frictional Characteristics of Sub-micro Structured Silicon Surfaces)

  • 한지희;한규범;장동영;안효석
    • Tribology and Lubricants
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    • 제33권3호
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    • pp.92-97
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    • 2017
  • The understanding of the friction characteristics of micro-textured surface is of great importance to enhance the tribological properties of nano- and micro-devices. We fabricate rectangular patterns with submicron-scale structures on a Si wafer surface with various pitches and heights by using a focused ion beam (FIB). In addition, we fabricate tilted rectangular patterns to identify the influence of the tilt angle ($45^{\circ}$ and $135^{\circ}$) on friction behaviour. We perform the friction test using lateral force microscopy (LFM) employing a colloidal probe. We fabricate the colloidal probe by attaching a $10{\pm}1-{\mu}m$-diameter borosilicate glass sphere to a tipless silicon cantilever by using a ultraviolet cure adhesive. The applied normal loads range between 200 nN and 1100 nN and the sliding speed was set to $12{\mu}m/s$. The test results show that the friction behavior varied depending on the pitch, height, and tilt angle of the microstructure. The friction forces were relatively lower for narrower and deeper pitches. The comparison of friction force between the sub-micro-structured surfaces and the original Si surface indicate an improvement of the friction property at a low load range. The current study provides a better understanding of the influence of pitch, height, and tilt angle of the microstructure on their tribological properties, enabling the design of sub-micro- and micro-structured Si surfaces to improve their mechanical durability.