• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1397-1403
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• 2011

In this paper, fabrication of sample holder was studied for an analysis of electromagnetic(EM) wave property in W-band(75 GHz~110 GHz). First of all, a propagation theory of EM wave was considered in the rectangular waveguide, and measurement technique was suggested for analysis of characteristics. A sample holder using in W-band was designed and fabricated, and used for analysis of material property and absorption ability using RAM samples. As a result, the sample holder test was verified exactly for measuring EM wave property of RAM sample. In the future, the proposed sample holder would like to be used for the EM wave property analysis in W-band.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.298-299
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• 2005

Differently from the tensile, transverse compression and torsion cases, the bending test of HTS tapes requires a lot of time and efforts, since the sample should be mounted successively onto bent sample holders in the order of decreasing radius and measuring the $I_c$ at each step. The influence of repeated cooling and warming experienced during these processes on the $I_c$ degradation can not be ignored. As a result, in this study, particularly. a new one-body type sample holder which provides continuous bending strains at 77K was devised. And, $I_c$ degradation behavior of Bi-2223 tapes under easy bending condition was investigated and compared that with other cases using Goldacker-type bending tester or respective sample holder.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.938-941
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• 2001

A tool holder system has been designed and builted to measure cutting forces in diamond turning. This system design includes a 3-component piezo-electric tranducer. Initial experiments with tool holder system included verification of its predicted dynamic characteristics as well as a detailed study of cutting parameters. In this research, tool holder system is modeled by considering the element dividing, material properties, and boundary conditions using MSC/PATRAN. Mode and frequency analysis of structure is simulated by MSC/NASTRAN, for the purpose of developing the effective design. In addition, tool holder system is verified by vibration test using accelerometer. Many cutting experiments have been conducted on 6061-T6 aluminum. Tests have involved investigation of velocity effects, and the effects of depth and feedrate on tool force. Cutting velocity has been determined to have negligible effects between 4 and 21㎧.(6) Forces generally increase with increasing depth of cut. Increasing feedrate does not necessarily lead to higher forces. Results suggest that a sample model may not be sufficient to describe the forces produced in the diamond turning process.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.105-115
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• 2015

Purpose: The accuracy for measuring the refractive power of hydrogel contact lenses by spectacle lens holder and contact lens holder was evaluated. The accuracy for each sample was also analyzed with water content and diopter categories. Methods: The hydrogel contact lenses used for measurement were classified into three categories in water content (38%, 43%, 58%). Also, three diopter categories of refractive power were used such as -3.000 D, -7.000 D, -10.000 D. And also, the reliability of measurement results were evaluated by measuring refractive power with spectacle lens holder and contact lens holder using an Manual lensmeter. Results: In case of spectacle lens holder method, the average value of refractive power was -3.3273D for -3.0000 D, -7.1306 D for -7.0000 D and -10.2944 D for -10.0000 D, respectively. In case of contact lens holder method, the average value of refractive power was -3.1060 D for -3.0000 D, -7.0028 D for -7.0000 D and -10.2611 D for -10.0000 D, respectively. In measurement of all diopters, the accuracy of contact lens holder method was better than spectacle lens holder method. Conclusions: From these results, it is judged that the refractive power of soft contact lens by manual lensmeter with contact lens holder have a higher accuracy than spectacle lens holder.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5A
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• pp.441-449
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• 2011

Sample timing offset (STO) and carrier frequency offset (CFO) are caused by inter-symbol interference (ISI), inter-carrier interference (ICI) and phase error in orthogonal frequency division multiplexing (OFDM) system. OFDM characteristic is sensitive about STO and CFO. So when ICI occurs, compensation is hard and complex equalizer is needed. In this paper, we propose an effective correction method using feedback process with pilot and synchronization symbol. After feedback with estimated value in frequency domain, STO and CFO are corrected by control sample & and holder and oscillator. As a result of simulation, we confirm that STO and CFO can be corrected without equalizer through feedback.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05b
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• pp.98-102
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• 2002

We investigated domains and conoscope under the polarizing microscope and the index of refraction on the c-plate GMO which has the ferroelectric and ferroelastic phase at room temperature. To observed the change of refractive index in connection with domain, we developed an apparatus to obtain the refractive index by measuring the Brewster's angle. The resolution of the minimum rotation angle of this apparatus is $0.001^{\circ}$. To obtain the refractive index map on the sample, the moving distance of XY stage loaded sample holder is 60 mm and the minimum moving distance is 0.002 mm. Also, To obtain the indicatrix for single crystal, vertical turntable with sample holder and XY stage was loading on horizontal turntable. The minimum resolution angle of this vertical turntable is $0.001^{\circ}$. We measured the refractive index of transparent materials such as ferroelectrics. In the case of $Gd_{2}(MoO_{4})_{3}$, the Brewster angle is $62.11^{\circ}$ and then, the refractive index is 1.8895 by using He-Ne Laser. Also the refractive distribution of c-plate GMO was obtained with $400{\mu}m{\times}120{\mu}m$.

• Current Photovoltaic Research
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• v.5 no.3
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• pp.89-94
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• 2017

We have examined the issues on the measurement of bifacial photovoltaic(PV) devices that should be considered in order to ensure a measurement accuracy beyond a certain level and the comparability between the bifacial PV devices. Based on the results of various experiments and previous studies, solutions for these measurement issues are suggested. The most significant technical issues in the performance measurement of the bifacial PV devices are 1) elimination of the effect due to the light reflection on the sample holder surface and 2) the measurement of the expected power generation gain in outdoor operation. The effect due to the light reflection on the sample holder surface can be eliminated by using an anti-reflective sample holder. In case of a reflective sample holder, if the bifacial device have a linear characteristic with respect to the irradiance of incident light, it has been confirmed (through some previous studies and additional experiment) that exact measurement results can be obtained by the correction of the measurement data. In addition, it was also confirmed that the expected power generation gain in the outdoor operation can be obtained by three different methods along with the basic concepts of the bifaciality coefficient, the albedo, and the effective front irradiance.

• Progress in Superconductivity and Cryogenics
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• v.7 no.4
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• pp.4-9
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• 2005

The degradation behavior of the critical current $(I_c)$ of Bi-2223 superconducting tapes under pressurized liquid nitrogen were investigated using a newly developed p-shaped sample holder which gives a series of bending strains to a sample. Three kinds of commercially available multi-filamentary Bi-2223 superconducting tapes were used. At atmospheric pressure, the Ie degradation behavior depended on the manufacturing process undergone by each tape. The tapes externally reinforced or densified by over pressure showed better bending strain tolerance than the Ag alloy-sheathed Bi-2223 tape. But these tapes showed a significant $I_c$ degradation when pressurized to 1 MPa in liquid nitrogen. For all samples, after depressurization to atmospheric pressure from 1 MPa, the Ie was completely recovered to its initial values at atmospheric pressure. When the samples were subjected to a thermal cycle wherein the tape was warmed up to room temperature after being depressurized from 1 MPa, it was found that the larger degradation of $I_c$ occurred at the regions where significant ballooning occurred, such as $0\%\;and\;0.2\%$. However, an improved ballooning damage tolerance was observed in the highly-densified tape.

• 한국전자현미경학회:학술대회논문집
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• 2001.11a
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• pp.18-22
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• 2001

A technique to characterize specific site of materials using a combination of a dedicated focused ion beam system(FIB), and Intermediate-voltage scanning transmission electron microscope(STEM) or transmission electron microscope(TEM) equipped with a scanning electron microscope(SEM) unit has been developed. The FIB system is used for preparation of electron transparent thin samples, while STEM or TEM is used for localization of a specific site to be milled in the FIB system. An FIB-STEM(TEM) compatible sample holder has been developed to facilitate thin sample preparation with high positional accuracy Positional accuracy of $0.1{\mu}m$ or better can be achieved by the technique. In addition, an FIB micro-sampling technique has been developed to extract a small sample directly from a bulk sample in a FIB system These newly developed techniques were applied for the analysis of specific failure in Si devices and also for characterization of a specific precipitate In a metal sample.

• Korean Journal of Computational Design and Engineering
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• v.10 no.5
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• pp.365-374
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• 2005

Most of people who are engaged in research and development find it difficult to solve the engineering problems creatively due to the lack of ideas. TRIZ is one of the emerging problem solving techniques that leads us to a very useful and clear solution. TRIZ consists of several tools such as ideal final result (IFR), physical and technical contradictions, 40 invention principles, resource, effect, etc. However, many designers think that TRIZ is hard to be applied to a design problem since there are several tools in TRIZ. Machine designers may want to see which tool is more effective than others. Thus, this paper provides sample solutions of a design problem: holder design for the bottle etching machine by applying several TRIZ tools. Difficulties in applying TRIZ to a design problem are discussed.