• 제목/요약/키워드: Scanning Angle

검색결과 572건 처리시간 0.016초

A hysteresis model for soil-water characteristic curve based on dynamic contact angle theory

  • Liu, Yan;Li, Xu
    • Geomechanics and Engineering
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    • 제28권2호
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    • pp.107-116
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    • 2022
  • The steady state of unsaturated soil takes a long time to achieve. The soil seepage behaviours and hydraulic properties depend highly on the wetting/drying rate. It is observed that the soil-water characteristic curve (SWCC) is dependent on the wetting/drying rate, which is known as the dynamic effect. The dynamic effect apparently influences the scanning curves and will substantially affect the seepage behavior. However, the previous models commonly ignore the dynamic effect and cannot quantitatively describe the hysteresis scanning loops under dynamic conditions. In this study, a dynamic hysteresis model for SWCC is proposed considering the dynamic change of contact angle and the moving of the contact line. The drying contact angle under dynamic condition is smaller than that under static condition, while the wetting contact angle under dynamic condition is larger than that under static condition. The dynamic contact angle is expressed as a function of the saturation rate according to the Laplace equation. The model is given by a differential equation, in which the slope of the scanning curve is related to the slope of the boundary curve by means of contact angle. Empirical models can simulate the boundary curves. Given the two boundary curves, the scanning curve can be well predicted. In this model, only two parameters are introduced to describe the dynamic effect. They can be easily obtained from the experiment, which facilitates the calibration of the model. The proposed model is verified by the experimental data recorded in the literature and is proved to be more convenient and effective.

Injection-Locking Coupled Oscillators를 이용한 빔 주사 용 능동 위상배열안테나의 설계 및 제작 (A design and fabrication of active phased array antenna for beam scanning using injection-locking coupled oscillators)

  • 이두한;김교헌;홍의석
    • 한국통신학회논문지
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    • 제22권8호
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    • pp.1622-1631
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    • 1997
  • A 3-stages Active Microstrip Phased Array Antenn(AMPAA) is implemented using Injection-Locking Coupled Oscillators(ILCO). The AMPAA is a beam scanning active antenna with capability of electrical scanning by frequency varation of ILCO. The synchronization of resonance frequencies in array elements is occured by ILCO, and the ILCO amplifies the injection signal and functions as a phase shifter. The microstrip ptch is operated as a radiation element. The unilateral amplifier is a mutual coupling element of AMPAA, eliminates the reverse locking signal and controls the locking bandwidth of ILCO. The possibility of Monolithic Microwave Integrated Circuits(MMIC) of T/R module is proposed by simplified and integrated fabrication process of AMPAA. The 0.75.$lambda_{0}$ is fixed for a mutual coupling space to wide the scanning angle and minimize the multi-mode. The AMPAA has beam scanning angle of 31.4.deg., HPBW(Half Power Beam Widths) of 26.deg., directive gain of 13.64dB and side lobe of -16.5dB were measured, respectively.

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용량 조정형 능동 집적 배열 안테나의 제작과 방사 방향 주사 특성 (Fabrication of the Capacitance Controlled Active Integrated Phased Array Antenna and It's Scanning Characteristics)

  • 최영규;남병근;신상열
    • 전기학회논문지
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    • 제56권10호
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    • pp.1807-1813
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    • 2007
  • This paper deals with extending the variable natural oscillation frequency range of an active integrated FET oscillator. In this paper, we conform experimentally that the variable range of the natural oscillation frequency is expanded about three times in the oscillator controlled by the varactor diode. When the frequency difference is given to the oscillators in the two element antenna system, phase difference appeared between the oscillators. The 2-, 3-, 4-, 5-element patch antenna arrays are composed for the beam scanning experiments. All the above patch antennas show good phased array characteristics. The range of the scanning angle is about $30^{\circ}$, and the radiation power is gradually increased from $50{\mu}W\;to\;200{\mu}W$. The radiation patterns we sharpened as the number of elements is increased.

The Morphology, Structure and Melting Behaviour of Cold Crystallized Isotactic Polystyrene

  • Marega, Carla;Causin, Valerio;Marigo, Antonio
    • Macromolecular Research
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    • 제14권6호
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    • pp.588-595
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    • 2006
  • The morphology, structure and melting behaviour of cold-crystallized isotactic polystyrene (iPS) were studied by differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and small angle X-ray scattering (SAXS). The polymer was found to crystallize according to the dual-lamellar stack model. The two populations of lamellae, along with a melting-recrystallization phenomenon, determined the appearance of multiple melting peaks in DSC traces. The annealing peak was attributed to the relaxation of a rigid amorphous phase, rather than to the melting of crystalline material.

주사 플라즈마 법(SPM)을 이용한 소수성 표면처리 (Control of Contact Angle by Surface Treatment using Sanning Plasma Method)

  • 김영기;최병정;양성채
    • 한국전기전자재료학회논문지
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    • 제23권1호
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    • pp.10-13
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    • 2010
  • The plasma processing technologies of thin film deposition and surface treatment technique have been applied to many industrial fields. This study is purposed Large-area uniformity and surface treatment on the stainless substrate. We treat surface of stainless by $CF_4$ plasma. $CF_4$ plasma is generated by using SPM(Scanning plasma method)which is kind a of CVD. Generally, SPM has been used for uniform surface treatment using a crossed electromagnetic field. The optimum discharge condition has been studied for the gas pressure, the magnetic flux density and the distance between substrate and electrodes. In result, contact angle is increased by surface treatment using $CF_4$ Plasma. Therefore we expect that SPM to control contact angle is applied to many industries.

벼 잎 표면에서 액적의 이방성 흐름 특성에 관한 연구 (A Study on the Anisotropic Flow Characteristics of Droplets on Rice Leaf Surface)

  • 김태완
    • Tribology and Lubricants
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    • 제33권6호
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    • pp.251-255
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    • 2017
  • In this study, we aimed to clarify the wettability and anisotropic flow characteristics of rice leaves as a basic study for engineering applications of anisotropic flow characteristics of rice leaf surface. To investigate the surface structure of rice leaf, the micro grooves and asperities of rice leaves were analyzed and quantified by scanning electron microscope, Confocal laser scanning microscopy, and stylus profilometer. The analysis of the structure of rice leaf surface confirmed that asymmetrical cone - like protrusions in leaf veins were inclined toward the leaf tip. The static contact angle test showed that the contact angle at the midline vein or leaf vein location where the micropapilla is concentrated is about $20^{\circ}$ higher than the leaf blade position. The contact angles of fresh and dried rice leave were also compared. The dried rice leaves showed a contact angle of about $5^{\circ}$ to $15^{\circ}$ higher than that of fresh leaves, suggesting that the volume of the protrusions decreased as the water was removed, thus reducing the contact area with the droplet. In the contact angle history test the hysteresis in the leaf tip direction was found to be much lower than that in the leaf petiole direction. This results can be explained that asymmetrical cone - like protrusions had a significant effect on the droplet flow characteristics through contact angle hysteresis experiment.

직사각형 다중 양자 우물 도파관의 모드특성 분석 : Scanning angle method를 사용한 새로운 접근 (Modal Analysis of Rectangular MQW Waveguide : A Novel Approach using Scanning Angle Method)

  • 임연섭;최영완
    • 대한전자공학회논문지SD
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    • 제37권4호
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    • pp.45-52
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    • 2000
  • 본 논문에서는 직사각형 다중 양자 우물 광 도파관의 간단하고 효율적인 분석을 위한 새로운 모의 실험방법을 제시한다. 우선적으로 2 차원 도파관 구조는 유효 굴절률 법을 사용하여 1 차원 도파관 구조로 변형되고 이렇게 얻어진 등가의 평면 다중 양자 우물 도파관의 도파 특성 행렬은 새롭게 제시된 각도 스캔법(scanning angle method)에 의하여 분석된다. 직사각형 다중 양자 우물 도파관의 유효 굴절률, 모드 전장세기, 광 구속 인자는 이 방법을 사용하여 효율적으로 얻을 수 있다. 모의 실험결과는 유한 요소 법에 기초된 해와 거의 정확한 일치를 보인다. 또한 직사각형 다중 양자 우물 도파관의 분석을 위한 두 가지의 근사 해석 방식을 새롭게 도입하고 그 방식들의 유효성을 검증하였다. 퍼터베이션 분석(perturbation analysis)을 사용하여 직사각형 다중양자 우물 도파관에서 전송되는 모드의 전력 손실 계수를 새롭게 유도하고 평면 다중 양자 우물 도파관 근사를 사용한 전형적인 방법의 결과와 비교하였다.

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Influence of Angle Ply Orientation on the Flexural Strength of Basalt and Carbon Fiber Reinforced Hybrid Composites

  • Mengal, Ali Nawaz;Karuppanan, Saravanan
    • Composites Research
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    • 제28권1호
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    • pp.1-5
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    • 2015
  • In this paper the influence of fiber orientation of basalt and carbon inter-ply fabrics on the flexural properties of hybrid composite laminates was experimentally investigated. Four types of basalt/carbon/epoxy inter-ply hybrid composite laminates with varying angle ply orientation of reinforced basalt fiber and fixed orientation of carbon fiber were fabricated using hand lay-up technique. Three point bending test was performed according to ASTM 7264. The fracture surface analysis was carried out by scanning electron microscope (SEM). The results obtained from the four laminates were compared. Lay-up pattern of $[0B/+30B/-30B/0C]_S$ exhibits the best properties in terms of flexural strength and flexural modulus. Scanning electron microscopy results on the fracture surface showed that the interfacial de-bonding between the fibers and epoxy resin is a dominant fracture mode for all fiber lay-up schemes.

원자현미경용 XY 스캐너의 아베 오차 최소화를 위한 최적 설계 및 원자 현미경의 측정 불확도 평가 (Optimal design of a flexure hinge-based XY AFM scanner for minimizing Abbe errors and the evaluation of measuring uncertainty of AFM system)

  • 김동민;이동연;권대갑
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2005년도 춘계학술대회 논문집
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    • pp.1438-1441
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    • 2005
  • To establish of standard technique of nano-length measurement in 2D plane, new AFM system has been designed. In this system, measurement uncertainty is dominantly affected by the Abbe error of XY scanning stage. No linear stage is perfectly straight; in other words, every scanning stage is subject to tilting, pitch and yaw motion. In this paper, an AFM system with minimum offset of XY sensing is designed. And XY scanning stage is designed to minimize rotation angle because Abbe errors occur through the multiply of offset and rotation angle. To minimize the rotation angle optimal design has performed by maximizing the stiffness ratio of motion direction to the parasitic motion direction of each stage. This paper describes the design scheme of full AFM system, especially about XY stage. Full range of fabricated XY scanner is $100um\times{100um}$. And tilting, pitch and yaw motion are measured by autocollimator to evaluate the performance of XY stage. Using this AFM system, 3um pitch specimen was measured. As a result, the uncertainty of total system has been evaluated.

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화상처리에 의한 섬유배향각 분포측정에 있어서 교차점합산법의 정밀도 (Accuracy of Intersection Counting Method in Measurement of Fiber Orientation Angle Distribution Using Image Processing)

  • 이상동;박준식;이동기;한길영;김이곤
    • 한국정밀공학회지
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    • 제15권12호
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    • pp.97-105
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    • 1998
  • The fiber oriented condition inside fiber reinforced composite material is a basic factor of mechanical properties of composite materials. It is very important to meausure the fiber orientation angle for the determination of molding conditions, mechanical characteristics, and the design of composite materials. In the work, the fiber orientation distribution of simulation figure plotted by PC is measured using image processing in order to examine the accuracy of intersection counting method. The fiber orientation function measured by intersection counting method using image processing is compared with the calculated fiber orientation function. The results show that the measured value of fiber orientation function using intersection counting method is lower than the calculated value, because the number of intersection between the scanning line and the fiber with smaller fiber aspect ratio is counted less than with larger fiber aspect ratio.

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