• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.86-89
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• 2003

Chemical Mechanical Planarization(CMP) has been accepted as the most effective processes for ultra large scale integrated (ULSI) chip manufacturing. However, as the polishing process continues, pad pores get to be glazed by polishing residues, which hinder the supply of new slurry. And pad surface is ununiformly deformed as real contact distance. These defects make material removal rate(MRR) decrease with a number of polishied wafer. Also the desired within-chip planarity, within wafer non-uniformity(WIWNU) and wafer to wafer non-uniformity(WTWNU) arc unable to be achieved. So, pad conditioning in CMP Process is essential to overcome these defects. The eletroplated or brazed diamond conditioner is used as the conventional conditioning. And. allumina long fiber, the jet power of high pressure deionized water, vacuum compression. ultrasonic conditioner aided by cavitation effect and ceramic plate conditioner are once used or under investigation. But. these methods arc not sufficient for ununiformly deformed pad surface and the limits of conditioning effect. So this paper focuses on the characteristics of diamond conditioner which reopens glazed pores and removes ununiformly deformed pad away.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.4
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• pp.17-24
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• 2003

Chemical mechanical polishing(CMP) has been applied for planarization of topography after patterning process in semiconductor fabrication process. Tungsten CMP is necessary to build up interconnects of semiconductor device. But the tungsten dishing and the oxide erosion defects appear at end-point during tungsten CMP. It has been known that the generation of dishing and erosion is based on the over-polishing time, which is determined by pattern selectivity. Fixed abrasive pad takes advantage of decreasing the defects resulting flam reducing pattern selectivity because of the lower abrasive concentration. The manufacturing technique of fixed abrasive pad using hydrophilic polymers is introduced in this paper. For application to tungsten CMP, chemicals composed of oxidizer, catalyst, and acid were developed. In comparison of the general pad and slurry for tungsten CMP, the fixed abrasive pad and the chemicals resulted in appropriate performance in point of removal rate, uniformity, material selectivity and roughness.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.8
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• pp.739-744
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• 2009

Rail-pad is an important and readily replaceable component of a railway track, as it is the elastic layer between the rail and the sleeper. Characteristics and useful lifetime prediction of rail-pad was very important in design procedure to assure the safety and reliability. In this paper, the degradation of rail pad properties as a function of their in-service life is studied with a view of developing a technique for predicting the optimum period of track maintenance with regard to pad replacement. In order to investigate the useful lifetime, the accelerate test were carried out. Accelerated test results changes as the threshold are used for assessment of the useful life and time to threshold value were plotted against reciprocal of absolute temperature to give the Arrhenius plot. By using the acceleration test, several useful lifetime prediction for rail-pads were proposed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.279-284
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• 2011

The calculation of Zwicker's loudness which is needed for multiple frequency response with a fine frequency resolution using the finite element (FE) procedure usually requires significant computation time since a numerical solution must be obtained for each considered frequency. Furthermore, if the analysis is the basis for an iterative optimization procedure this approach imposes high computational cost. In this work, we present an efficient approach for obtaining Zwicker's loudness via the Pad$\acute{e}$ approximants and applying in an acoustical topology optimization procedure. The paper is focused on an efficient and accurate calculation of Zwicker's loudness, design sensitivity analysis, and the acoustical topology optimization method by using Pad$\acute{e}$ approximants. The paper compares the efficient algorithm to results obtained by a standard FEM. Comparison are made both in terms of accuracy and in terms of CPU-times needed for the calculation.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.11
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• pp.168-173
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• 2001

The chemical mechanical polishing (CMP) is generally consisted of pad, slurry including abrasives and so on. However, there are some problems in a general CMP: defects, a high Cost of Consumable (CoC), an environmental problem. The slurry including abrasives especially gives rise to not only increase a CoC, but also prohibition from achieving an eco-process. This paper introduces an abrasive capsulation pad to achieve an eco-process decreasing abrasives used is CMP. The binder wth a water a water swelling and a water soluble characteristic is used for an auto-conditioning, and the $CeO_2$abrasive is selected for an abrasive capsulation pad. Comparing with a conventional CMP, an abrasive capsulation pad appears good characteristics in ILD CMP and is able to achieve an eco-process decreasing wasted slurry.

• Journal of Communications and Networks
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• v.13 no.2
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• pp.113-124
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• 2011

Electrocardiography (ECG) is a widely accepted approach for monitoring of cardiac activity and clinical diagnosis of heart diseases. Since cardiologists have been well-trained to accept 12-lead ECG information, a huge number of ECG systems are using such number of electrodes and placement configuration to facilitate fast interpretation. Our goal is to design a wireless ECG system which renders conventional 12-lead ECG information.We propose the three-pad ECG system (W3ECG). W3ECG furthers the pad design idea of the single-pad approach. Signals obtained from these three pads, plus their placement information, make it possible to synthesize conventional 12-lead ECG signals.We provide one example of pad placement and evaluate its performance by examining ECG data of four patients available from online database. Feasibility test of our selected pad placement positions show comparable results with respect to the EASI lead system. Experimental results also exhibit high correlations between synthesized and directly observed 12-lead signals (9 out of 12 cross-correlation coefficients higher than 0.75).

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.100-105
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• 2021

This paper proposes the polydimethylsiloxane (PDMS) blade coating method for fabrication of paper-based analytical device (PAD) that is able to monitor the disease diagnosis and progress without special analytical equipment. The mold that has PAD design is easily modified by using laser cutting technique. And the fabricated mold is used for hydrophobic barrier formation by blade coating. We have optimized the stable formation of PDMS hydrophobic barrier as blade coating condition, which is established by analyzing the structure of the PDMS hydrophobic barrier and change of hydrophilic channel size as thickness of the ink and contact time with the chromatography paper. Based on optimal condition, we demonstrate that PAD as biosensor can apply to detect protein, glucose, and metal ion without special analysis equipment.

• Nuclear Engineering and Technology
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• v.16 no.2
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• pp.70-79
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• 1984

With the help of the nuclear computational system for a large LMFBR (KAERI-26 group cross section library/1DX/2DB), the reactivity coefficients for the diagrid expansion and the pad expansion at the beginning of cycle of the equilibrium core of SUPER-PHENIX I are calculated and reviewed. the core is described using R-Z geometry model, and a two-dimensional multigroup diffusion theory is used. For reference cases, reactivity calculations for radial and axial uniform expansion are performed, and also calculated are reactivity variations due to changes in material density and core volume. The reactivity coefficient for the diagrid expansion is calculated to be -0.553pcm/mil. The temperature coefficient corresponding to the above value is -1.0766pcm/$^{\circ}C$ and is well in accord with the French datum of -1.09pcm/$^{\circ}C$ within 1.2% difference. With the use of 4he calculational method for the diagrid expansion effect, reactivity calculations for the pad expansion bringing about nonuniform expansion are performed, which show that the calculational method is very useful in the analysis of the pad expansion effect. The reactivity coefficients for the pad expansion are calculated to be -0.2743 pcm/mil and -0.2786pcm1mi1 for the averaged expansion model and for the integrated pancake model, respectively. Under the assumption of the free expanding core the temperature reactivity coefficients for each model are obtained to be -0.5766pcm/$^{\circ}C$ and -0.5858pcm/$^{\circ}C$, both of which agree with the French datum of -0.574pcm/$^{\circ}C$ within 2% difference.

• The Journal of the Korea Contents Association
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• v.17 no.7
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• pp.144-157
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• 2017

Although student satisfaction is important in university development, there have been many studies in this area. Especially student satisfaction is closely related to emotional aspect, but most studies have tended to study it with cognitive view. To suggest the model of student satisfaction with hedonic view, the model which we present in this study includes professor presence and interaction, PAD(pleasure, arousal, dominance), satisfaction(dependent variable). Through reviewing previous studies, we expect that these professor presence and students' interaction effect PAD, in turn, PAD effect satisfaction. Survey research is employed to test hypotheses involving professor presence, students' interaction, PAD and satisfaction. Previous researches, such as education, marketing, game, have been referenced to measure constructs. We collected data involving students in a university, and used 219 respondents to analyze these data using LISREL structural modeling. Professor presence had positive effects on professor-student interaction, pleasure, arousal, and dominance. Also professor-student interaction had positive effect on pleasure and arousal, and student-student interaction had positive effects on pleasure and arousal, dominance. As a result, PAD had effects on students' satisfaction. In the final section, we discussed several limitations of our study and suggested directions for future research. We concluded with a discussion of managerial implications, including the potential to advance understanding learning in a university.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.8
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• pp.386-396
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• 2006

We implemented the Drug-Pad Moxibustion Method in order to improve the conventional moxibustion therapy. This method is aimed to eliminate burning wounds and smoke, which are the defects of conventional moxibustion therapy. And we performed to verify the efficiency by comparing the Drug-Pad Moxibustion Method with the conventional Indirect Moxibustion Therapy. We measured the body heat and the lasting time of blood circulation improvement using thermography. The moxibustion therapy has two kinds of effects: The formers are pharmacological effects of the Moxa's vasodilators and antioxidants. The latters are thermal effects which cause improvement of the blood circulation. To remove the demerits without omission of above therapeutic effects, we extracted the vasodilators and antioxidant compounds from the Moxa-$CH_2Cl_2$ fraction Moxa-EtOAc and composed the moxibustion kit with $(Ba_{0.8}\;Sr_{0.2})_{0.996}\;Y_{0.004}\;TiO_2+0.5_{WT}\;SiO_2%$ Positive Temperature Coefficients Thermistor. The experimental demonstrations have been made by the stimulating the spot which is CV4(Kwan-Won), CV8(Shin-Guel), CV12(Jung-Wan) acupuncture points of the conception vessel meridian(CV). And stimulating time was one hour. We divided the subjects into 5 groups such as no stimulation group, conventional Indirect Moxibustion group, only Drug-Pad stimulation group, only heat stimulation group, and Drug-Pad Moxibustion group. In the different cases, we have measured the body heat in pre-stimulation, just after stimulation, 2 hours after, and 4 hours after. The body heats of the group who were stimulated by the Drug-Pad Moxibustion Method were increased by over the $2^{\circ}C$. And the body heats of the group who were stimulated by the Indirect Moxibustion Method were increased by average the $1^{\circ}C$. We have evaluated that the Drug-Pad Moxibustion Method is improvement on the conventional Indirect Moxibustion Method by the heat-increasing rate is 200% and the lasting time is 150% with the body heat of the abdominal region. In the conclusions, We have implemented the Drug-Pad Moxibustion Method and evaluated the efficiency of the Drug-Pad Moxibustion Method comparing with the conventional Indirect Moxibustion Method.