• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기설비전문위원
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• pp.37-39
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• 2007

금속의 전기 비저항 측정방법은 일반적으로 4단자, van der Pauw, Four-Point Probe(FPP), eddy current 방법 등이 있다. 이들의 측정방법들은 각각 다르지만 동일한 시료에 대한 전기 비저항 측정값은 거의 같은 결과를 나타내어 야 한다. 금속 전기 비저항의 정밀측정에 대한 연구를 위하여 비자성 금속인 STS 316 시료를 선정하여 측정한 결과 4단자와 van der Pauw 방법으로 측정된 비저항은 각각 $75.86{\mu}g\Omega{\cdot}cm$(2.273 %IACS), $75.80{\mu}g\Omega{\cdot}cm$(2.275 %IACS)이며, 측정 불확도는 0.25 %로서 거의 동등한 결과를 나타냈고, Four Point Probe(FPP) 방법으로 측정된 비저항은 $75.36{\mu}g\Omega{\cdot}cm$(2.288 %IACS), 측정 불확도는 0.45 %, eddy current 방법으로 측정된 비저항은 $76.63{\mu}g\Omega{\cdot}cm$(2.25 %IACS), 측정 불확도는 0.64 %로 나타났다.

• 마이크로전자및패키징학회지
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• 제24권3호
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• pp.77-81
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• 2017

Pulse electroplating of Ni-P alloy was studied to fulfill the material requirement to the advanced vertical probe tip in wafer probe card. The major concerns are for the electrical conductivity and yield strength. Plating parameters such as current density, duty cycle and solution components were examined to obtain the nanocrystal structure and proper percentage of phosphorus, leading to how to control the nanocrystal grain growth and precipitation of $Ni_3P$ after heat treatment. Among the parameters, the amount of phosphorus acid was the main factor affecting on the grain size and sheet resistance, and the amount of 0.1 gram was appropriate. Since hardness in Ni-P alloy is increased by as-plated nanocrystal structure plus precipitation of $Ni_3P$, the concentration of P less than 15 at% was better choice for the grain coarsening without minus in hardness value. The following heat treatment made grain growth and dispersion of precipitates adjustable to meet the target limit of resistance of $100m{\Omega}$ and hardness number of over 1000Hv. The Ni-P alloy will be a candidate for the substitute of the conventional probe tip material.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.731-734
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• 2002

This paper presents the assessment of input impedance of a sectoral cylindrical cavity-backed slot antenna excited by a probe. This antenna is proposed to be an element of array that can be assembled to be the antenna for UHF TV broadcasting system. The integral equations are derived based on boundary conditions of the proposed structure and are expressed in terms of dyadic Green's functions and unknown currents. The unknown current densities are solved by the Method of Moments and the input impedance is derived subsequently. Numerical results show the variation of input impedance, for the specified dimensions of the antenna, as a function of frequency. This result is validated by measurement and found that the result is sufficiently accurate. The result from this study is useful for the design of a sectoral cylindrical cavity-backed slot antenna excited by a probe.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.464-475
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• 2009

Electrical resistivity can be used for porosity estimation. In order to improve previously developed ERCP(Electrical Resistivity Cone Probe), 4ERP(4 Electrical Resistivity Probe), which has Wenner array at the tip of probes, has been developed. In properties of current flow Wenner array measures electrical properties of undisturbed area during penetration and relatively correct measurements are guaranteed without polarization. Furthermore, Wenner array equation can estimate electrical resistivity without extra calibration. 4ERP is developed into 2 types, penetration and fixation. Penetration type has wedge-shaped tip. Considering disturbance minimization, fixed type has plane tip. Fixed type 4ERP in consolidation cell measure electrical resistivity increment along porosity decrease, and penetration type 4ERP measured resistivity profile along the depth in chamber. Applying Archie's law, porosity profile was estimated with electrical resistivity. The tests result suggests that 4ERP can be new site investigation equipment with little disturbance.

• 한국결정학회:학술대회논문집
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• 한국결정학회 2003년도 춘계학술연구발표회
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• pp.7-7
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• 2003

Heteromagnetic nanostructures, which consist of two or more different layers such as nonmagnet, insulator, ferromagnet, antiferromagnet, and superconductor, have been widely used in current and likely future spintronics devices. Their many intriguing magnetic properties are originated from a variety of magnetic interactions at relevant length scales at or near interfaces and between different constituent layers as well as laterally different regions in chemical and magnetic heterogeneity. The fundamental properties can thus differ along depth and laterally in the film plane, depending on their relevant coupling length scales. The entire properties may be characterized by interface properties and/or the depth-varying properties of the individual constituent layers, and lateral inhomogeneity as well. It is a challenge to investigate both depth-varying properties and lateral heterogeneity in such heteromagnetic nanostructures. In this talk, soft x-ray magneto-optical effect as a nanometer scale probe of a variety of heteromagnetic structures is presented and its related noble techniques are introduced. For instances, magnetization vector imaging to investigate vector spin configurations in the film plane is presented, as well as the Kerr rotation, ellipticity, and intensity measurements as a depth sensitive probe on the atomic scales.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권4호
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• pp.225-230
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• 2004

An electromagnetic actuator has been designed and fabricated for Probe-based data storage applications. The actuator consists of permanent magnets(SmCo) housing and a media Platform which is connected to the Si frame by four couples of Si leaf springs. In order to generate electromagnetic force, Cu coils were electroplated under the media platform. The magnetic field distribution was calculated with 3D Finite Element Method of Maxwell 3D program. The field strength felt by Cu coils was estimated to be about 0.33T when the distance between the media platform and permanent magnets is $200\mu\textrm{m}$. The static and dynamic motions of the actuator were analyzed by FEM method with ANSYS 5.3. The measured displacements of the actuator were about $\pm$$92\mu\textrm{m}$ for input current of $\pm$40㎃ and the resonance frequency was 100Hz. The proposed electromagnetic actuator can be utilized for media driver of probe-based data storage system.

• Current Optics and Photonics
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• 제5권5호
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• pp.532-537
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• 2021

We present a compact endoscopic probe in a needle form which has a fast beam-scanning capability for optical coherence tomography (OCT). In our study, a beam-scanning OCT imaging needle was fabricated with a 26G syringe needle (0.46 mm in outer diameter) and a thin OCT imaging probe based on the stepwise transitional core (STC) fiber. The imaging probe could freely rotate inside the needle for beam scans. Hence, OCT imaging could be performed without rotation or translation of the needle body. In our design, the structural integrity of the needle's steel tubing was preserved for mechanical robustness. Probing the optical signal was performed through the needle's own window formed at the end. For hand-held operation of our imaging needle, a light and compact scanner module (130 g and 45 × 53 × 60 mm³) was devised. Connected to the imaging needle, it could provide rotational actuation driven by a galvanometer. Because of its finite actuation range, our scanner module did not need a fiber rotary joint which might add undesirable complexity. The beam scan speed was 20 Hz and supported 20 frames per second at the maximum for endoscopic OCT imaging.

• Current Optics and Photonics
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• 제7권3호
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• pp.283-296
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• 2023

An intraoral spectral domain optical coherence tomography (SD-OCT) system has been developed, using a custom-built hand-held scanner and spectrometer. The hand-held OCT probe, based on a microelectromechanical systems scanner and a self-built miniaturized drive circuit, had a field of view sufficient for dental diagnosis. The spectrometer using a fabricated f-theta lens provided the image depth required for dental diagnosis. The axial and transverse resolutions of the OCT system in air were 7.5 ㎛ and 12 ㎛ respectively. The hand-held probe could scan an area of 10 × 10 mm², and the spectrometer could image along a depth of 2.5 mm. To verify the utility of the developed OCT system, OCT images of tooth hard and soft tissues were acquired, and a user-interface program for diagnosis was developed. Early caries and microcracks that were difficult to diagnose with existing methods could be found, and the state of restoration could be observed. Measuring the depth of the gingival sulcus, distinguishing subgingival calculus, and detecting an implant under the gingiva suggested the possibility of the SD-OCT system as a diagnostic for dental soft tissues. Through the presented OCT images, the capability of the developed SD-OCT system for dental diagnosis was demonstrated.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권7호
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• pp.424-429
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• 2004

The 4-probe method with a voltage tap on terminals has been used for the measurement of the critical current of multi-strand high-T$_{c}$ superconducting(HTS) cables. And the critical current of cables is obtained as the measured total current divided by the number of conductor when the terminal voltage exceeds the predetermined criterion of critical current. However, because of the non-uniform current distribution due to the different critical current, shapes, and other characteristics of each conductor, this is not applicable method to the multi-strand HTS cable. To determine the critical current of multi-strand HTS cable, the critical current of each conductor must be measured with different method. h this paper, the current distribution and the critical current of each conductors in multi-strand cable were measured with specially made Pick-up coils and voltage taps. It is presented that the real critical current of multi-strand is smaller than sum of each conductors. The main cause of non-uniform current distribution is the difference between the resistances appeared in each HTS wires.s.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.426-429
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• 1999

In this paper, we have provided the measurement technique of the grounding mesh resistance by field measurements. The standard of measurement is specified in the IEEE Std 81.2-1991 and JEAC 5001-1988, which is the the fall-of-potential method by test-current injection, but this method is difficult to apply at field, where is small around a electric power substation of domestic. For the convenient measurement method, space of assistant probe and quantity of test-current injection are changed step for step. As the result, ' the proposed measurement technique of grounding mesh resistance is that the space of current and potential probes must be fixed at 150rn from a grounding mesh, the test-current injection has to keep 5A or more.