• 제목/요약/키워드: tilt angle

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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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    • 2009.10a
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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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Optical design of an LED lamp composed of 3-Component RGB chips (3-Component RGB chip으로 구성된 LED 전구의 광학적 설계)

  • Kang, Seok-Hoon;Song, Sang-Bin;Kwon, Yong-Seok;Yeo, In-Seon
    • Proceedings of the KIEE Conference
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    • 2002.11a
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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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Internal Structure Optimization to enhance the Thermal Performance of an Air-cooled Lithium-ion Battery Pack (공냉식 리튬 이온 배터리 팩의 열 성능 향상을 위한 내부 구조 최적화)

  • Li, Quanyi;Cho, Jong-Rae
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.12
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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.

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

  • Youngchul Chung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1996.11a
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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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The Effect of Various Interventions on an Adult with Scoliosis (척추측만증 치료를 위한 다양한 중재의 적용-사례연구)

  • Choi, Woon-Ho
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.17 no.2
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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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Real-Time Moving Object Tracking System using Advanced Block Based Image Processing (개선된 블록기반 영상처리기법에 의한 실시간 이동물체 추적시스템)

  • Kim, Dohwan;Cheoi, Kyung-Joo;Lee, Yillbyung
    • Korean Journal of Cognitive Science
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    • v.16 no.4
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    • pp.333-349
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    • 2005
  • In this paper, we propose a real tine moving object tracking system based on block-based image processing technique and human visual processing. The system has two nun features. First, to take advantage of the merit of the biological mechanism of human retina, the system has two cameras, a CCD(Charge-Coupled Device) camera equipped with wide angle lens for more wide scope vision and a Pan-Tilt-Zoon tamers. Second, the system divides the input image into a numbers of blocks and processes coarsely to reduce the rate of tracking error and the processing time. Tn an experiment, the system showed satisfactory performances coping with almost every noisy image, detecting moving objects very int and controlling the Pan-Tilt-Zoom camera precisely.

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

  • Shin, Sun Hye;Yu, Mi;Jeong, Gu Young;Yu, Chang Ho;Kim, Kyung;Jeong, Ho Choon;Kwon, Tae Kyu
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.3
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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.

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

  • Han, Ji-Hee;Han, Gue-Bum;Jang, Dong-Yong;Ahn, Hyo-Sok
    • Tribology and Lubricants
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    • v.33 no.3
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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.

Fish length dependence of acoustic target strength for 12 dominant fish species caught in the Korean waters at 75 kHz (한국 연근해에서 어획된 주요 12어종의 75 kHz에 대한 음향 반사 강도의 체장 의존성)

  • Lee, Dae-Jae
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.41 no.4
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    • pp.296-305
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    • 2005
  • Acoustic target strength (TS) of 12 commercially important fish species caught in the Korean waters had been investigated and their results were presented. Laboratory measurements of target strength on 12 dominant fish species were carried out at a frequencies of 75 kHz by single beam method under the controlled condition of the water tank with the 241 samples of dead and live fishes. The target strength pattern on individual fish of each species was measured as a function of tilt angle, ranging from $-45^{\circ}$ (head down aspect) to $45^{\circ}$ (head up aspect) in $0.2^{\circ}$ intervals, and the averaged target strength was estimated by assuming the tilt angle distribution as N ($-5.0^{\circ}$, $^15.0{\circ}$). The 75 to fish length relationship for each species was independently derived by a least - squares fitting procedure. Also, a linear regression analysis for all species was performed to reduce the data to a set of empirical equations showing the variation of target strength to fish length and fish species. An empirical model for fish target strength(TS, dB) averaged over the dorsal aspect of 158 fishes of 7 species and which spans the fish length(L, m) to wavelength(${\lambda}$, m) ratio between 6.2 and 21.3 was derived: TS: 27.03 Log(L)-7.7Log(${\kanbda}$)-17.21, ($r^2$=0.59).