• Title/Summary/Keyword: focal point

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The Past Landscapes of Gyeong-Po Lake (경포호의 옛모습 추정- 기록자료를 중심으로 -)

  • Kim Tae-Kyung
    • Journal of the Korean Institute of Landscape Architecture
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    • v.32 no.4
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    • pp.83-93
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    • 2004
  • Due to the pressures from surrounding conditions, the current Gyeong-Po Lake has been loosing its original appearance. Historically, the value of Gyeong-Po Lake has been highlighted at the Ru-Jeongs, which were once used to enjoy the various lakeside landscapes. However, the changes in physical appearance of the lake surroundings have ruined the value of the Ru-Jeongs, and even more changed the view point. As an initiating effort to reestablish and to manage the traditional visual landscapes of the lake, this study puts its emphasis on the traditional point of view. Also, this study tries to find the traditional visual values that are not visible at the current time, based on historic literature such as historic documents, paintings and poems. One of the important findings of this study is that viewing the different landscapes was more highly valued than their physical configurations in historic literatures, and that the focal points in viewing landscape were the Ru-Jeongs(누정). Hence, this study suggests that it is necessary to set the Ru-Jeongs, including Gyeong-Po(경포), Bang-Hye(방해), Hwan-Sun(환선), and Ho-Hae(호해), as the focal points for viewing the landscapes in order to reestablish and manage the traditional landscapes of Gyeong-Po Lake.

Pulsed Radiofrequency Treatment of Pain Relieving Point in a Soft Tissue

  • Lee, Jeong-Soo;Yoon, Kyung-Bong;Kim, In-Ki;Yoon, Duck-Mi
    • The Korean Journal of Pain
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    • v.24 no.1
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    • pp.57-60
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    • 2011
  • Pulsed radiofrequency (PRF) treatment of nervous tissue has been proposed as a less neurodestructive technique alternative to continuous RF heat lesioning. Recently, clinical reports using PRF have shown favorable effects in the treatment of a variety of focal pain areas, even in non-nervous tissues; however, the mechanism of effect underlying this treatment to non-nervous tissue remains unclear. We report the case of a 67-year-old male who presented with pain reliving point in the posterior neck. The patient had pain in the posterior neck for 3 years. The pain subsided with pressure applied to a point in the posterior neck. There were no specific abnormal findings on laboratory testing and radiologic examinations. After PRF treatment to the pain-relieving point, he had pain relief which lasted more than 5 months.

Design and Construction of Hexgonal Ring-type Transducers for Ultrasonic Hyperthermia (초음파 hyperthermia용 육각환 변환기의 설계및 제작에 관한 연구)

  • Cho, Young-Hwan;Sung, Koeng-Mo
    • The Journal of the Acoustical Society of Korea
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    • v.8 no.4
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    • pp.5-12
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    • 1989
  • In the clinical application of ultrasonic hyperthermia, selective heating of tumor is essential and thus precise control of ultrasonic intensity in both tumor and normal tissue is needed. In this paper, a hexagonal array transducer for ultrasonic hyperthermia is designed and manufactured of which focal point and focal region can be ocntrolled by the digital phase control circuit proposed by authors. Profiles of the focussed ultrasound beam in water and those of temperature in phantom were determined. The experimental and computed results are in good agreement.

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A Method for Measurement of Limiting Intrinsic Non-Uniformity Due to Process in CCD-Multiplexers for Focal Plane Arrays

  • Bhan, R.K.;Saxena, R.S.
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.2 no.1
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    • pp.87-92
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    • 2002
  • We present a simple experimental method for determination of limiting intrinsic fixed-pattern non-uniformity (NU) due to fabrication process in two-dimensional CCD multiplexers (MUXs) that are used for hybrid focal plane arrays. Here, this is done by determining separately the two NUs viz. that are $V_T$ dependent and $V_T$ independent. From these measurements, process dependent NU can be extracted. It is argued that $V_T$ dependent NU can be eliminated by designing novel input circuits whereas $V_T$ independent NU, primarily, dependent on process control and material variations may be reduced but cannot be eliminated completely and hence limits the FPA performance eventually.

Facile Synthesis of Aldehyde-focal Fréchet Type Dendrons and Dendrimers via Staudinger/Aza-Wittig Reactions

  • Han, Seung-Choul;Jin, Sung-Ho;Lee, Jae-Wook
    • Bulletin of the Korean Chemical Society
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    • v.32 no.10
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    • pp.3624-3628
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    • 2011
  • Fr$\acute{e}$chet-type dendritic benzaldehydes were efficiently synthesized using 3,5-dihydroxybenzaldehyde as an aldehyde focal point functionalized unit by adding a generation to the existing dendron or direct oxidation of Fr$\acute{e}$chet-type dendritic benzyl alcohols. These dendritic benzaldehydes were applied for the construction of dendrimers containing secondary amines as connectors via Staudinger/aza-Wittig Reactions with ${\alpha}$,${\alpha}'$,-diazidop-xylene core.

Design and Experimental Demonstration of Coaxially Folded All-reflective Imaging System

  • Xiong, Yupeng;Dai, Yifan;Chen, Shanyong;Tie, Guipeng
    • Current Optics and Photonics
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    • v.3 no.3
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    • pp.227-235
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    • 2019
  • With slimmer, lighter and all-reflective imaging systems in high demand for consumer and military applications, coaxially folded optical image systems are widely considered because they can extend focal length and reduce track length. Most of these systems consist of multiple surfaces, and these surfaces are machined on one element or grouping processing on two elements. In this paper, we report and first experimentally demonstrate an all-aluminum all-reflective optical system which consists of two optical elements, with two high order aspherical surfaces in each element. The coaxially folded system is designed with Seidel aberration theory and advanced optimization with Zemax. The system is made of all-aluminum material processing by single point diamond turning (SPDT). On this basis, we completed the system integration and performed an imaging experiment. The final system has the advantages of short track length and long focal length and broad application prospects in the micro-unmanned aerial vehicle field.

Property of Focal Spot of Electron Beam Depending on the Anode Angle of X-ray Tube Using a Finite Element Method (유한요소법을 이용한 X-선관 양극각도에 의존하는 전자빔 초점 특성 연구)

  • Park, Tae-Young;Noh, Young-Il;Lee, Sang-Suk;Park, Rae-Jun;Kim, Ki-Seon
    • Journal of the Korean Magnetics Society
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    • v.25 no.2
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    • pp.52-57
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    • 2015
  • The focal spot of electron beam depending on the anode angle in the structure and major parts of the X-ray tube was investigated by the OPERA-3D/SCALAR simulation program. The simulation worked on four spaces with with two spaces, including anode and cathode of X-ray tube, by applying the finite element method analysis. The analytical model and dimension for the emission orbit of thermal electrons made from one filament of the focused X-ray cathode is affected to the penumbra of detector for the X-ray depending on any real focal spot size. The model shape of focusing cap and focusing tube with an anode target angle and a cathode filament is analyzed by the current density distribution of thermal electrons. The focusing width of thermal electrons for the X-ray tube depended on the anode angle (${\theta}$). The focusing value of electron beams at a region of anode angle having $10^{\circ}{\sim}17^{\circ}$ maintained to below value of $70{\mu}m$. The minimum focal size of the electron beam was $40{\mu}m$ at an anode angle of $15^{\circ}$. The focused X-ray tube of many variables depended on the thermionic emission of hot electrons from the target trajectory. The focusing tube will contribute to the real design of X-ray for the development of future diagnosis medical device.

Disparity and Image Characteristics of Stereoscopic Video Affecting on Viewing Safety (스테레오스코픽 비디오의 시청안전성에 영향을 미치는 변위 및 화면 특성)

  • Seo, Young-Ho;Bae, Yun-Jin;Kim, Woo-Youl;Kim, Dong-Wook
    • Journal of Broadcast Engineering
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    • v.17 no.5
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    • pp.789-807
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    • 2012
  • The purpose of this paper is to find various disparity factors in conjunction with situations and contexts of the contents that cause viewer's discomfort, which is to make a content production guideline for viewer's safety, eventually. As a methodology, we extract the experimental data by letting various viewers push a pre-defined key as long as they feel discomfort during watching stereo 3D contents. For each contents, we extract the disparities and disparity changes for the focal point, vicinity of the focal point (ROI, region of interest), and the whole image. For each contents, each point or part of contents is analyzed to find the factors causing discomfort with the two prepared data with watching the contents in 3D. Then, all the analyzed data are re-analyzed to find the strength of each factor. The results from the analyses are explained from the factors having relatively high strength first. It includes the factors that are not known as well as the ones that we can already guess.

Improved Focal Liver Lesion Detection by Increasing Flip Angle During Gadoxetic Acid-Enhancement in MRI (Gadoxetic acid 조영증강 자기공명영상에서 숙임각 변화에 따른 국소 간종양 검출능 비교)

  • Lee, SeJy;Kim, Young-Keun
    • Journal of radiological science and technology
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    • v.38 no.2
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    • pp.115-120
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    • 2015
  • To study the differences of focal liver lesion image detection at 3 minute, 10 minute and 15 minute time points on gadoxetic acid (GA)'s enhanced MR imaging with a flip angle (FA) of $30^{\circ}$ compared with a $11^{\circ}$. The subjects were 69 patients evaluated with GA enhanced MR imaging with 3.0T MR scanner. The patients are total 35(23 men and 7 women at the mean age of 60.4 years), hepatocellular carcinoma(23) and metastsis(12) except for normal, cyst and hemangioma. After GA was injected, FA $11^{\circ}$ and $30^{\circ}$ images were obtained at 3 minute, 10 minute and 15 minute time points respectively. After quantitative and qualitative assessment of each image was done, statistical analysis was performed by using the independent sample T-test. From both quantitative and qualitative assessment of 3 minute and 10 minute MR images after the injection of GA, FA $30^{\circ}$ images was found to be superior than FA $11^{\circ}$, but there were no statistical significance. However, at 15 minute time point, Statistically significant FA $30^{\circ}$ image(p<0.05) was better than FA $11^{\circ}$ therefore, the FA $30^{\circ}$ improves the focal liver lesion detection. FA $30^{\circ}$ of MR image can detect liver lesion more sensitively than the existing $FA11^{\circ}$ image after GA contrast enhancement at 15 minute time point.

Trigger Point Injection for Myofascial Pain Syndrome (근막 통증 증후군의 통증 유발점 주사)

  • Kim, Chul-Hong;Park, Jin-Woo
    • The Journal of Korean Orthopaedic Ultrasound Society
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    • v.7 no.2
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    • pp.127-131
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    • 2014
  • Skeletal muscles which are the largest part of human body may develop pain and dysfunction. The myofascial pain syndrome that has trigger points as a unique characteristic is a major cause of morbidity. Trigger points are focal, hyperirritable painful areas located in a taut band of skeletal muscle. They produce local area pain and a referred pattern pain and often accompany chronic joint dysfunction. Various modalities are used to inactivate trigger points in myofascial pain syndrome. Trigger-point injection has been shown to be one of the most effective treatment modality to provide prompt relief of symptoms. This review article presents general concept of myofascial pain syndrome and technique of trigger point injection.

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