• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.10
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• pp.1049-1055
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• 2004

Chemical Mechanical Polishing (CMP) is referred to as a three body tribological system, because it includes two solids in relative motion and the CMP slurry. On the assumption that the abrasives between the pad and the wafer could be a major reason not only for the friction force but also for material removal during polishing, the friction force generated during CMP process was investigated with the change of abrasive size and concentration of CMP slurry. The threshold point of average coefficient of friction (COF) with increase in abrasives concentration during interlayer dielectric (ILD) CMP was found experimentally and verified mathematically based on contact mechanics. The predictable models, Mode I (wafer is in contact with abrasives and pad) and Mode II (wafer is in contact with abrasives only), were proposed and used to explain the threshold point. The average COF value increased in the low abrasives concentration region which might be explained by Mode I. In contrast the average COF value decreased at high abrasives concentration which might be regarded to as Mode II. The threshold point observed seemed to be due to the transition from Mode I to Mode II. The tendency of threshold point with the variation of abrasive size was studied. The increase of particle radius could cause contact status to reach transition area faster. The correlation between COF and material removal rate was also investigated from the tribological and energetic point of view. Due to the energy loss by vibration of polishing equipment, COF value is not proportional to the material removal rate in this experiment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.8
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• pp.774-787
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• 2011

This paper deals with quantitative analysis about the characteristics of GNSS(Global Navigation Satellite System) signals contaminated with multipath signals and day-to-day repeatability of the navigation solution and SNR(Signal to Noise Ratio) caused by multipath signals using the collected data from GPS receiver installed on KSLV-I which was on standby on the launch pad at Naro Space Center. Since the GPS antennas, surrounding environments and GPS satellite orbits were very slightly changed with respect to the day, the repeating pattern of the solution and SNR caused by the multipath signals was verified from the collected data. Analytic result of the multipath effects and day-to-day repeatability of the navigation solution and SNR observed at the launch pad would be used for obtaining more stable performance of the GPS receiver when the satellite launch vehicles are on standby.

• Journal of Music and Human Behavior
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• v.13 no.1
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• pp.1-18
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• 2016

This study examined the correlation between the rhythm reproduction performance and cognitive function of school-aged children. A total of 59 third grade elementary students participated in this study. An iPad-based rhythm reproduction task, the Digit Span Test (DST), the Children's Color Trails Test (CCTT), and a self-paced tapping task via a MIDI keyboard were conducted for each participant. The results demonstrated that scores at each stage of the iPad-based rhythm reproduction test showed different patterns of correlation with cognitive function test scores. This result suggests that accuracy of a simple rhythm task is correlated to speed of self-paced tapping (second). Also cognitive function may affect rhythm grouping ability. Results of this analysis for each of 20 rhythm items showed that there was a common rhythm characteristics that correlated with executive function, working memory or self-paced tapping speed. These results indicate that rhythm ability is related to, and predictive of, the level of cognitive functioning in elementary school students and can be used as an useful parameter when examining cognitive function of school-aged children in multifaceted dimensions.

• Knowledge Management Research
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• v.14 no.3
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• pp.37-54
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• 2013

Technology standards have gained importance as global market becomes more competitive. Since a technology acknowledged as a standard brings significant benefits to the developer firm, firms in the IT industry tend to pursue standardization for the technology, being it proprietary or open. However, the paths or strategic implications are seldom discussed in academia. Therefore, our study uses iPhone of Apple, one of the proprietary standards successes, to further understand corporate strategies over two standard choices. Our case study suggests that iPhone's entry timing was optimal for creating a new mobile environment. Design excellence and user-friendly interface increased networking effects and switching costs among consumers. Apple developed independent mobile operating system (iOS) through improvement on the existing operating system. During the process, Apple chose proprietary standard and, by installing the same UX on its sibling products such as iPod Touch or iPad, overcame the subsequent problems that might arise from the limited use of iOS. Based on the capability of concurrently developing both hardware and software, Apple connected operating system, machine, and contents, which deems to contribute to its proprietary standards success. We argue that this strategy should be considered for firms which plan proprietary standard strategy.

• Aerospace Engineering and Technology
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• v.10 no.2
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• pp.133-145
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• 2011

This paper is about the results in Qualification Management activity performed between the Autonomous Test(AT) season(August. 2008) of Launch Complex and the 2nd flight test season(June. 10, 2010) of KSLV-I. All cryogenic fluids(LOX, $LN_2$) and compressed gases(Air, $GN_2$, GHe) were qualified by qualification management activity during AT(Autonmous Test), QT(Qualification Test) season for LP(Launch Pad) and LVAB(Launch Vehicle Assembly Building) and FT(Flight Test) season of KLSV-I. As the results, total 428 times of check analysis and 111 times of full analysis were performed.

• The Korea Journal of Herbology
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• v.23 no.4
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• pp.171-177
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• 2008

Objectives: This study presents a reversed-phase high-performance liquid chromatography- pulsed amperometric detection(RP-HPLC-PAD) method for the determination of puerarin and daidzin in Puerariae Radix extract and Chinese medicinal preparations. Methods: Chromatographic separation was performed using a 10% acetonitrile with a reversed-phase column(Unison UK-C18, $100mm{\times}2.0mm$ I.D.; $3{\mu}m$). The analyses were detected by pulsed amperometric detector(PAD) in alkaline conditions by combining with post-column NaOH solution. Geniposide was used as an internal standard. Results: The limit of detection(S/N=3) and the limit of quantification(S/N=10) were 0.025 ng, 0.075 ng for puerarin, and 0.05 ng, 0.15 ng for daidzin, respectively. The intra- and inter-day precisions(RSDs) were less than 6.5% and average recoveries of puerarin were 99.7-101.3% and those of daidzin were 101.0-102.8%. Conclusions: According to above results, we developed a determination method for puerarin and daidzin in Puerariae Radix with high sensitivity and selectivitely.

• Journal of the Korean Society of Clothing and Textiles
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• v.47 no.2
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• pp.311-322
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• 2023

In this study, the properties of various material combinations were evaluated and an ideal material for fabricating protection pads for women's army combat uniforms was determined. Eight specimens were used for the evaluation: two types of materials, namely thermoplastic polyurethane for 3D printing, T and ethylene-vinyl acetate, E; two infill densities, namely 10%, 10 and 30%, 30; two types of pad designs, i.e., without holes, A and with holes, B; 2×2×2=8 and control E. The tensile strength, flexural strength, impact absorption, and weight of these specimens were evaluated. Results revealed that E was the most flexible material; however, its tensile strength and impact absorption were very low. Protection pads made from T (T-10A, T-10B, T-30A, and T-30B) had excellent tensile strength and impact absorption; however, they had low performance in ease of movement. Alternatively, protection pad with holes and an infill density of 30% produced using a combination of T and E had a high initial tensile modulus and exhibited excellent impact absorption. Moreover, it was flexible and light, which satisfies the standards and conditions required by protection pads. However, if T-E-10A and T-E-30B exhibited low impact absorption, as required, they can be regarded as appropriate materials for protection pads.

• The Journal of Advanced Prosthodontics
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• v.15 no.6
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• pp.302-314
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• 2023

PURPOSE. The aim of this study was to classify the shapes of retromolar pads and assess their morphometric differences using a 3D model. MATERIALS AND METHODS. Two hundred fully edentulous or Kennedy Class I partially edentulous patients (400 retromolar pads) were enrolled. Scan data of the definitive mandibular casts produced through functional impressions were obtained using a 3D laser scanner. Seven parameters (transverse diameter, longitudinal diameter, transverse-contour length, longitudinal-contour length, longitudinal/transverse diameter ratio, longitudinal/transverse-contour length ratio, and angle of the retromolar pad line to the residual alveolar ridge line) were measured using image analysis software. Subsequently, the pads were classified according to the shape. Statistical analyses were performed using 95% confidence intervals. RESULTS. Classifying the retromolar pads into three shapes led to high intra-examiner reliability (Cronbach's alpha = 0.933). The pear shape was the most common (56.5%), followed by oval/round (27.7%) and triangular (15.8%) shapes. There were no significant differences between the left and right sides according to the shape and no significant differences in any parameter according to age. The transverse diameter and longitudinal/transverse diameter ratio differed between sexes (P < .05). The triangular shape had a significantly different transverse diameter, transverse-contour length, longitudinal/transverse diameter ratio, and longitudinal/transverse-contour length ratio compared with the pear and oval/round shapes (P < .05). CONCLUSION. From a clinical reliability standpoint, classifying retromolar pads into three shapes (oval/round, pear-shaped, and triangular) is effective. The differences in the sizes among the shapes were attributed to the transverse measurement values.

• 발명특허
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• v.37 no.3
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• pp.14-17
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• 2012

애플의 태블릿PC 브랜드 명인 "아이패드(IPAD)". 전 세계 태블릿PC 시장을 새롭게 만들어 냈을 뿐만 아니라, 전세계 태블릿 시장의 60% 이상을 석권하고 있는 제품이다. 그런데, 이 대단한 제품이 중국에서는 그 상표권을 중국 업체에 선점당하여 판매금지를 당할 위기에 처해있다. 애플은 중국 IPAD 상표권을 양도 받았다고 주장하지만, 중국 법원은 이미 1심에서 중국의 션전 프로뷰사의 손을 들어주었다. 피해금액만도 천문학적인 액수가 될 것으로 전망되는 이 상표분쟁은 도대체 어떻게 시작되었으며, 무엇이 문제가 되고 있는지, 사건의 처음부터 현재까지 상세하게 살펴보자.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.763-766
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• 2003

A direct parameter extraction method using several two-port parameter equations derived in cutoff and active bias modes has been studied to obtain an accurate Gummel-Poon BJT model. First, dc model parameters were extracted from slopes and y-axis intercepts of I-V curve and Gummel plot. The pad capacitances and junction capacitance parameters were determined by using measured S-parameter sets in the cutoff bias. The resistance and transit time parameters were extracted by using measured S-parameter sets in the active bias.