• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1998년도 춘계학술대회논문집
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• pp.199-204
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• 1998

In this study, a method is presented which can be used to measure the fiber orientation distribution for thickness direction during injection molding using image processing. The intensity method in used for measuring the distribution. And the effects of fiber content, injection molding condictions on the orientation function are also discussed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표대회 논문집(III)
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• pp.773-778
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• 1998

For imaging of concrete specimens using radar, the principles of radar, microwave, and the electromagnetic properties of concrete are discussed. Experimental data obtained from radar measurement of concrete specimens with no steel bars at three different frequency bandwidths of 2~3.4 GHz, 3.4~5.8 GHz and 8~12 GHz are processed to determine the thickness of the specimens. A signal processing scheme has been implemented to visualize the concrete specimens. The purpose of this study is to determine particular frequency range appropriate for measuring the thickness of concrete specimens using radar.

• 한국공작기계학회논문집
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• 제12권1호
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• pp.16-23
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• 2003

Keeping the layer thickness constant is very essential for improving the shape accuracy in the stereolithography process. The layer thickness is created by recoating process, and also affected by recoating parameters such as blade speed and thickness. The created layer in this process can determine the whole accuracy of the entire parts. The aim of this paper is to improve the accuracy of the layer thickness by adjusting the recoating process parameters. Several experiments with different recoating conditions are Performed to find the optimal recoating parameters that produce the most accurate layer thickness. The effective recoating method is suggested by measuring and analyzing the cured layer thickness.

• 마이크로전자및패키징학회지
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• 제30권3호
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• pp.88-93
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• 2023

고대역폭 메모리(HBM)에 대한 수요가 증가하고 직경이 더 큰 웨이퍼의 핸들링 기술이 발전함에 따라 본딩 웨이퍼의 두께 균일성에 대해 신뢰성을 확보할 수 있는 측정 방법이 요구되고 있다. 본 연구에서는 300mm 웨이퍼를 대상으로 웨이퍼의 전 영역에 대해 TTV를 측정할 수 있는 모듈을 설계 제직하고, 측정 모듈의 설계를 바탕으로 발생할 수 있는 측정 오차를 분석하였으며, 웨이퍼의 처짐과 척의 기구적 오차를 고려한 모델 해석을 통해 예측된 기울기 값에 따른 측정 오차를 추정하였다. TTV 측정 모듈은 웨이퍼 지지를 위한 센터 척과 리프트 핀을 활용하여 웨이퍼의 전체 영역에 대해 측정이 가능하도록 하였다. 모달 해석을 통해 모듈의 구조적 안정성을 예측하였으며, 구동부와 측정부 모두 100Hz 이상의 강성을 갖는 것을 확인하였다. 설계된 모듈의 측정 오차를 예측한 결과 두께 1,500um의 본딩 웨이퍼를 측정할 경우 예측된 측정 오차는 1.34nm로 나타났다.

• Applied Microscopy
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• 제50권
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• pp.8.1-8.7
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• 2020

Two thickness measurement methods using an electron energy loss spectroscopy (EELS) and 10a convergent beam electron diffraction (CBED) were compared in an Fe-18Mn-0.7C alloy. The thin foil specimen was firstly tilted to satisfy 10a two-beam condition. Low loss spectra of EELS and CBED patterns were acquired in scanning transmission electron microscopy (STEM) and TEM-CBED modes under the two-beam condition. The log-ratio method was used for measuring the thin foil thickness. Kossel-Möllenstedt (K-M) fringe of the $13{\ba{1}}$ diffracted disk of austenite was analyzed to evaluate the thickness. The results prove the good coherency between both methods in the thickness range of 72 ~ 113 nm with a difference of less than 5%.

• 한국기계가공학회지
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• 제14권4호
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• pp.151-159
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• 2015

In this study, we developed an automated contact-type thickness measurement machine that continuously and precisely measures the thickness of a PCB module product using multi-LVDT sensors. The system contains a measurement part to automatically measure the thickness in real time according to the set conditions with an alignment supply unit and unloading unit to separate OK and NG products. The sensors were calibrated before assembly in the measuring machine, and precision and accuracy performance tests were also performed to reduce uncertainty errors in the measurement machine. In the calibration test, the precision errors of the LVDT sensor were determined to be $1-3{\mu}m$ as 0.1% at the measuring range. A measurement error of 0.8 mm and 1.0 mm thickness test standards were found to be $1{\mu}m$ and $4{\mu}m$, and the standard deviations of two 1.0 mm products were measured as $14{\mu}m$ and $8{\mu}m$, respectively. In the measurement system analysis, the accuracies of test PCB standards were found to be $2{\mu}m$ and $3{\mu}m$, respectively. From the results of gage repeatability and reproducibility (R & R) crossed, we found that the machine is suitable for the measurement and process control in the mass production line as 7.92% of total gage R & R and in seven distinct categories. The maximum operating speed was limited at 13 pcs/min, showing a value good enough to measure.

• 마이크로전자및패키징학회지
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• 제27권4호
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• pp.127-133
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• 2020

고분자 재료인 접착제와 금속 피착재 사이의 정량적인 접착강도 측정은 중요하다. 고분자 재료인 접착제와 금속 피착재 사이의 접착강도 측정 시, 피착재의 종류와 두께 변화가 접착강도에 미치는 영향에 대해 연구하였다. 금속 피착재의 종류로는 알루미늄과 스텐리스강 2종류가 선택되었으며, 접착강도의 측정에는 돌리테스트와 전단시험이 사용되었다. 인장응력 방식의 돌리테스트로 고분자 접착제와 금속 피착재 사이의 접착강도 측정 시, 금속 피착재의 두께 변화는 접착강도의 크기에 거의 영향을 미치지 않았으나, 피착재의 종류에 따라 접착강도는 다르게 나타났다. 반면, 전단시험으로 고분자 접착제와 금속 피착재 사이의 접착강도 측정 시, 금속 피착재의 상대적 두께 변화는 접착강도의 크기에 영향을 주었다. 이유는 전단시험 시 접착부의 모서리 부분에서 발생하는 피착재의 휘어짐 현상은 접착부에 추가적인 인장응력을 발생시켜 접착강도를 낮추는데 기여하기 때문이다. 이 연구의 결과, 돌리테스트는 피착재의 두께가 변해도 접착강도의 변화가 거의 없기 때문에 고분자 접착제와 금속 피착재의 정량적인 접착강도 측정 시 널리 사용될 것으로 예상된다.

• Journal of Veterinary Science
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• 제19권6호
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• pp.840-845
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• 2018

The purpose of this study was to propose a standard for differentiation between normal dogs and patients with hyperadrenocorticism (HAC) by measuring skin thickness via ultrasonography in small breed dogs. Significant changes in skin thickness of patients treated with prednisolone (PDS) or patients with HAC treated with trilostane were evaluated. Skin thickness was retrospectively measured on three abdominal digital images obtained from small breed dogs weighing < 15 kg that underwent abdominal ultrasonography. Mean skin thickness of normal dogs was $1.03{\pm}0.25mm$ (mean ${\pm}$ SD). Both the HAC and PDS groups showed significantly thinner skin than that in the normal group. Seven of the 10 HAC patients treated with trilostane had increased skin thickness. The area under the curve value of 0.807 was based on the receiver operating characteristics (ROC) curve for differentiating normal dogs from HAC patients. Sensitivity was 76% and specificity was 73% when skin thickness was less than the 0.83 mm cutoff value. In conclusion, measurement of skin thickness in small breed dogs by using ultrasonography is likely to provide clinical information useful in differentiating HAC patients from normal dogs. However, exposure to PDS, trilostane, and other conditions may have a significant effect on skin thickness.

• The Journal of the Acoustical Society of Korea
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• 제29권3E호
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• pp.140-145
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• 2010

In the present study, tubular polyvinyl chloride (PVC) cortical bone mimics that simulate the cortical shell of long bones were used to validate the axial transmission technique for assessing the cortical thickness by measuring the ultrasonic velocities along the cortical shell of long bones. The ultrasonic velocities in the 9 PVC cortical bone mimics with wall thicknesses from 4.0 to 16.1 mm and inner diameters from 40 to 300 mm were measured as a function of the thickness by using a pair of custom-made transducers with a diameter of 12.7 mm and a center frequency of 200 kHz. In order to clarify the measured behavior, they were also compared with the predictions from a theory of guided waves in thin plates. This phantom study using the PVC cortical bone mimics provides useful insight into the dependencies of ultrasonic velocities on the cortical thickness in human long bones.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.240-245
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• 2000

In this study, thickness, density and effective thermal conductivity of frost forming on the horizontal cylinder were measured with various air temperature and humidity. Reynolds number and temperature of cooling surface are controlled 17300 and $-l5^{\circ}C$ respectively. In each case of air temperature $5^{\circ}C,\;10^{\circ}C,\;15^{\circ}C,$ varying absolute humidity, experiments were executed. In measuring frost surface temperature and thickness of frost layer, infrared thermocouples and CCD camera were used. Frost was gathered from cylinder to measure mass of frost layer. Experimental data showed that the thickness and effective thermal conductivity of the frost layer increase with respect to time. Thickness of frost layer increase with humidity increasing, and density of frost layer increase with air temperature rising. Frost growth with air temperature and density of frost layer with humidity are affected by whether dew point is below or above freezing point.