• Title/Summary/Keyword: curve angle

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Elastic flexural and torsional buckling behavior of pre-twisted bar under axial load

  • Chen, Chang Hong;Yao, Yao;Huang, Ying
    • Structural Engineering and Mechanics
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    • v.49 no.2
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    • pp.273-283
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    • 2014
  • According to deformation features of pre-twisted bar, its elastic bending and torsion buckling equation is developed in the paper. The equation indicates that the bending buckling deformations in two main bending directions are coupled with each other, bending and twist buckling deformations are coupled with each other as well. However, for pre-twisted bar with dual-axis symmetry cross-section, bending buckling deformations are independent to the twist buckling deformation. The research indicates that the elastic torsion buckling load is not related to the pre-twisted angle, and equals to the torsion buckling load of the straight bar. Finite element analysis to pre-twisted bar with different pre-twisted angle is performed, the prediction shows that the assumption of a plane elastic bending buckling deformation curve proposed in previous literature (Shadnam and Abbasnia 2002) may not be accurate, and the curve deviates more from a plane with increasing of the pre-twisting angle. Finally, the parameters analysis is carried out to obtain the relationships between elastic bending buckling critical capacity, the effect of different pre-twisted angles and bending rigidity ratios are studied. The numerical results show that the existence of the pre-twisted angle leads to "resistance" effect of the stronger axis on buckling deformation, and enhances the elastic bending buckling critical capacity. It is noted that the "resistance" is getting stronger and the elastic buckling capacity is higher as the cross section bending rigidity ratio increases.

Cephalometric Angular Measurements of the Mandible Using Three-Dimensional Computed Tomography Scans in Koreans

  • Kim, Yong Hyun;Kang, Seok Joo;Sun, Hook
    • Archives of Plastic Surgery
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    • v.43 no.1
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    • pp.32-37
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    • 2016
  • Background We conducted this study to analyze the values of the key cephalometric angular measurements of the mandible using 3-dimensional (3D) computed tomography scans. Methods In the 106 enrolled patients, a 3D cephalometric analysis was performed to measure the angular variables of the mandible. These values were compared between the two sides and between the two sexes. Results The frontal measurements revealed that the mandibular body curve angle was larger on the left (Lt) side (right [Rt], $141.24{\pm}7.54$; Lt, $142.68{\pm}6.94$; P=0.002) and the gonial angle was larger on the right side (Rt, $134.37{\pm}8.44$; Lt, $131.54{\pm}7.14$; P<0.001). The sagittal measurements showed that the gonial angle was larger on the right side (Rt, $134.37{\pm}8.44$; Lt, $131.54{\pm}7.14$; P>0.05). Further, the transverse measurements revealed that the mandibular body curve angle was larger on the right side (Rt, $140.28{\pm}7.05$; Lt, $137.56{\pm}6.23$; P<0.001). Conclusions These results provide an average of the mandibular angular measurements for the Korean population, establishing a standard for determining surgical patient groups and outcome evaluations in the field of mandible contour surgery.

Dip Estimation for Overhead Transmission Conductor using Catenary Angle (카테너리 각도를 이용한 가공송전도체의 이도 추정)

  • Kim, Sung-Duck;Sohn, Hong-Kwan;Jang, Tae-In
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.21 no.5
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    • pp.112-119
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    • 2007
  • Under normal operating condition, the conductor of overhead transmission line could be always hold it's clearance within the safety margin that is specified in the line design guide of power company. Hence it may be very important to measure/or monitor the dip of the conductor, when building a new line, re-tensioning for an aged conductor, or monitoring dynamic line rating to maximize power capability. In this paper, we suggest a new method to estimate the dip and tension by catenary angle of the conductor. Since most conductors in overhead transmission lines show typical catenary curves, it can be uniquely determined the catenary curve for the conductor from the catenary angle at tower. Based on the catenary curve, the dip or horizontal tension can be easily estimated. Through some simulation and simple experimental results, it is verified that the suggested method can be effectively applied to measure/or monitor conductor dips and tensions in the overhead transmission lines.

Lower Body Shape Classification of Chinese Males in Their 20s by Analyzing Photographic Measurement (사진측정(寫眞測定)에 의한 중국(中國) 20대(代) 남성(男性)의 하반신(下半身) 형태(形態) 분류(分類))

  • Lee, So-Young;Shim, Boo-Ja
    • Journal of Fashion Business
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    • v.11 no.1
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    • pp.61-74
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    • 2007
  • Photographic measurement was first made with the subjects of 190 males in their 20s residing in the Ningbo area, Zhejiang Province in China. In this second report, lower body shapes were classified and discriminated by using indirect measurement, measurement items, and lower body analysis. The following sums up the research: 1. The subjects were $8.85^{\circ}$ (hip breadth angle), $1.58^{\circ}$ (abdomen upper angle), $11.80^{\circ}$ (hip upper angle), and $5.12^{\circ}$ (lateral lower body posture angle). 2. The subjects of Chinese males in their 20s showed three types of lower bodies: Bow Legs & Slight Slant of Lateral Lower Body Type (30.5%)-gap between legs, curve waist-hip contour, average abdomen-hip profile, and lateral lower body posture were slightly slanted forward. Adjacent Straight Legs & Slight Slant of Lateral Lower Body Type (35.8%)-adjacent straight between legs, curve waist-hip contour, slim abdomen-hip profile, and lateral lower body posture were slightly slanted forward. Balance Legs & Large Slant of Lateral Lower Body Type (33.7%)-average between legs, straight waist-hip contour, protruding hip profile, and lateral lower body posture were largely slanted forward. 3. Eight useful variables for the categorization of the subjects' lower body types were chosen through stepwise discriminant analysis, and the hit ratio of discrimination was 97.9%.

GafChromic RTQA Film Dosimetry for Laser Beam with Photodynamic Therapy (GafChromic RTQA Film을 이용한 광역학적 치료용 레이저의 선질 측정)

  • Lee, Byung Koo;Lim, Hyun Soo;Kenar, Necla
    • Journal of Biomedical Engineering Research
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    • v.34 no.2
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    • pp.73-79
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    • 2013
  • Purpose: The purposes of this study were to measure the dose distribution of Photodynamic therapy(PDT) laser with 635 nm wavelength using GafChromic film. Method & Result: We made each output 300 J by changing mW and sec using the laser beam radiation mode such as C.W(Continuous Wave) mode, Pulse mode and Burst Pulse mode and measured the does at 0 mm and 5 mm of distance from optic fiber catheter end to the film, and at 5 mm distance by changing the angle of the end of the optic fiber catheter as $0^{\circ}$ and $0.5^{\circ}$. The radiated film was scanned and OD(Optical Density) was compared. And two-dimensional isodose curves were obtained and the consistency of shapes was compared. It was confirmed that there was consistency between optic density and the dose radiated on the film when we radiated GafChromic film by changing distance and angle of 300 J output in each radiation mode coordinating mW and sec. Conclusion: In this study, we could identify the stability according to changes in laser beam modes, changes in output according to distance, changes in uniformity according to angle, and beam profiles using GafChromic film, and we could also get two-dimensional isodose curve. It was found that small change in the distance and angle that is made when optic fiber catheter was contacted on the treatment area did not make big effects on the output of beam and the uniformity of dose, and it was also found that GafChromic film could be utilized for the purpose of QA of PDT laser beam.

Characteristics of Gold and Silver Bimetallic Surface Plasmon Resonance Chip in Intensity Measurement Mode and Calculation of Refractive Index using Critical Angle (반사광 측정 모드에서 금과 은의 쌍금속 표면 플라즈몬 공명 칩의 특성과 임계각을 이용한 굴절률 계산)

  • Kim, Hyungjin;Lee, Sung-Youp;Kim, Hong Tak;Yang, Ki-Won;Sohn, Young-Soo
    • Journal of Sensor Science and Technology
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    • v.24 no.6
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    • pp.423-428
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    • 2015
  • A bimetallic chip made of gold and silver was investigated in intensity interrogation mode to confirm enhancement of the SPR sensor resolution. Both reflectance curves of the bimetallic chip and the conventional gold chip was acquired and compared. The line width of the reflectance curve of the bimetallic chip was narrower than that of the conventional Au chip, resulting in steeper tangential slope. The reflectance was monitored at the angle related to the steepest tangential slope. The change in reflectance of the bimetallic chip was larger than that of the Au chip. The critical angle was analyzed by differentiating the reflectance with respect to incident angle twice. Acquiring the critical angle regarding to the sample informs the refractive index of the sample. Using various concentration of Bovine Serum Albumin, we confirmed that refractive index was linearly related to variation of reflectance of the bimetallic chip.

Comparison and Evaluation of Dynamic Modulus of Hot Mix Asphalt with Different Shift Factors (전이함수 결정법에 따른 아스팔트 혼합물의 동탄성계수 비교평가)

  • Kim, Hyun-Oh;Lee, Kwan-Ho
    • International Journal of Highway Engineering
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    • v.7 no.1 s.23
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    • pp.49-61
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    • 2005
  • The dynamic modulus of hot mix asphalt can be determined according to the different combinations of testing temperature and loading frequency. The superposition rule is adapted to get the master curve of dynamic modulus for each hot mix asphalt. There are couple of different methods to get the shift factor which is a key for making the master curve. In this paper, Arrehnius, 2002 AASHTO, and experimental method was employed to get the master curve. Evaluation of dynamic modulus for 25mm base course of hot mix asphalt with granite aggregate and two asphalt binders(AP-3 and AP-5) was carried out. Superpave Level 1 Mix Design with gyratory compactor was adopted to determine the optimum asphalt binder content(OAC) and the measured ranges of OAC were between 4.1% and 4.4%. UTM was used for laboratory test. The dynamic modulus and phase angle were determined by testing on UTM, with 5 different testing temperature(-10, 5, 20, 40, & $55^{\circ}C$) and 5 different loading frequencies(0.05, 0.1, 1, 10, 25 Hz). Using the measured dynamic modulus and phase angle, the input parameters of Sigmoidal function equation to represent the master curve were determined and these will be adopted in FEM analysis for asphalt pavements. The shift factor and activation energy for determination of master curve were calculated.

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Effects of Edged Curve Angle of Rotary Blade on Entwining Spreaded Rice Straw in Paddy (볏짚 시용(施用) 답(畓)의 Rotary 경운시(耕耘時) 날의 궤적(軌跡) 진입각(進入角)이 볏짚 감김에 미치는 영향(影響))

  • Yi, Woon Young;Kim, Soung Rai
    • Korean Journal of Agricultural Science
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    • v.13 no.1
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    • pp.103-112
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    • 1986
  • This study was carried out to prevent the entwining of rice straw on rotary shaft and blade where rice straw was spreaded on paddy field as an organic source before rotary tilling. The rotary tillage was conducted in the paddy field having the soil moisture contents of 30%, 39%, 59% in dry basis and spreaded rice straw (450kg/10a) of 30cm, 45cm, 90cm length with the edged curve angles of rotary blade of $30^{\circ}$, $40^{\circ}$, $50^{\circ}$, $55^{\circ}$ at Yuseung area. And the test were performed on the plot which has width of 30cm and 5cm length and the quantity of entwined rice straw was analized. The test results were summarized as the followings. 1. Entwining phenomenon of rice straw was decreased as the blade edged curve angle increased. The edged curve angle of rotary blade must be determind by considering the characteristics of soil cutting resistance, tilling torque and entwining phenomenon of rice straw. But according to the entwining phenomenon of rice straw only, the edged curve angle of rotary blade should be bigger than $55^{\circ}$ for design. 2. Amount of entwining rice straw was minimized when soil moisture contents was 30 percent (d. b.). It would be better that rotary tillage is performed when soil moisture contents is lower than 30 percent in dry basis. 3. Amount of entwining rice straw was minimized when the length of rice straw was 30cm with $55^{\circ}$ edged curve angle. Therefore, it would be better to chop rice straw as 30cm. 4. Entwining phenomenon of rice straw was decreased as the forward speed decreased. To decrease the entwining rice straw, rotary tillage should be done with forward fist gear (0.35m/s).

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Characteristics of a Bimetal-Layer Chip of a Surface Plasmon Resonance Sensor in the Intensity Interrogation for Tumor Marker Detection

  • Kim, Hyungjin;Kim, Chang-duk;Sohn, Young-Soo
    • Journal of Sensor Science and Technology
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    • v.25 no.4
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    • pp.243-246
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    • 2016
  • The characteristics of a bimetallic surface plasmon resonance (SPR) chip were investigated to detect a tumor biomarker, carcinoembryonic antigen (CEA). The linewidth and the tangential slope of the reflectance curve of the bimetallic SPR chip was compared with those of the reflectance curve of a conventional gold (Au) SPR chip. The changes in reflectance in response to the variation in CEA in the critical concentration range were analyzed at an angle where the tangential slope of the reflectance curve was maximum. From linear regression analysis, the sensitivity of the bimetallic SPR chip with respect to the CEA in critical concentration was obtained.

Dynamic Behavior Analysis of a Helical Coil Spring Using Space Curve Vector (공간곡선 벡터에 의한 원통 코일 스프링의 동적 거동 해석)

  • 김대원;김종수
    • Journal of KSNVE
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    • v.8 no.6
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    • pp.1015-1022
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    • 1998
  • This paper addresses the results of an experimental and analytical research of a helical coil spring subjected to dynamic behavior using space curve vector after considering elongation rate. Vibrations in helical coil spring can be divided into 3 modes such as vibrations of coil spring center axis' vertical direction. axis' horizontal direction, direction about center axis. However. these 3 modes are dependent one another and are characterized as coupled. The dependency was proved through both theoretically and experimentally analyzing the results of dynamic characteristics of coil spring center axis' vertical direction vibration by transfer matrix method using the governing equation of static equilibrium. Also this paper shows that pitch angle and active coils in coil spring affect the dynamic spring characteristics of the above 3 modes and are especially sensitive to the mode for vibration of axis' horizontal direction which most affects especially on dynamo stability of helical coil spring.

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