• Korean Journal of Materials Research
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• v.11 no.6
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• pp.441-447
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• 2001

A study on the TiN coating layer in small holes on the Purpose of die-casting dies application has been performed with a PACVD process. For the hole having diameter of 4 mm. the uniform TiN coating layer in the hole to the depth of 20 mm was achieved using DC pulsed power source. To understand the forming mechanism of TiN coating layer, plasma diagnosis on Ti, $N_{2}^{+}$ and A $r^{+}$ emissions was carried out during plasma coaling process by optical emirssion spectroscopy. When the duty ratio was equal or over 50%, the Peaks of Ti,$ N_{2}^{+}$ and A $r^{+}$ emission were obviously observed. While duty ratio was equal or under 28.6%, no peaks for Ti, $N_{2}^{+}$ and A $r^$ were observed and the formation of TiN coating layer was rarely observed. For the coating in 4 mm hole diameter, the coating layer with bipolar process was two times deeper than that with unipolar process.

• Journal of the Korean Geotechnical Society
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• v.34 no.8
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• pp.27-36
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• 2018

The collapse behavior of ground subsidence caused by continuous loss of particles depends on the saturated condition and density of the ground. In this study, types of ground subsidence were classified based on the saturated condition and each type was performed on the different relative density to analyze the influence factors on the collapse behavior by distinct element method. According to analysis results, the relatively small amount of settlement occurred on the dense ground and a cavity was created under dense-unsaturated ground. In contrast, loose ground showed the large amount of settlement and collapsed immediately without cavity formation even if the unsaturated ground was simulated. The results demonstrated that because the relative density has influence on the mechanical interlocking and saturated condition has influence on the inter-particle force, these are important factors to change the collapse behavior.

• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.178-184
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• 2010

The aim of this work is the fabrication of polyelectrolyte microcapsules composed of biocompatible polymers such as chitosan, heparin and alginate, to encapsulate the fluorescein isothiocyanate(FITC)-albumin, and to investigate the protein release behavior therefrom. Polyelectrolyte capsules with 4-layer structures could be prepared with biocompatible materials by oppositely charged adsorption using melamin-foramide as a template. Transmission electron microscope(TEM), scanning electron microscope(SEM) and optical microscope confirmed hollow capsule structures. Protein release before and after encapsulation was monitored with a UV-Vis spectrometer. Microcapsules have different behaviors depending on the kind of polyelectrolyte polymers, chitosan-heparin capsules or chitosan-alginate capsules. In conclusion, the polyelectrolyte multilayer shells can be switched between an open and closed state by means of tuning the pH value.

• Archives of design research
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• v.17 no.3
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• pp.245-254
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• 2004

In Accordance with the change of design paradigm, the design process has changed into user-centered workflow from designer-centered workflow. Since the purpose of the past research methods is quantitative analysis or the understanding of the present situation, it doesn't fit in practical design that expressed the user's needs. Therefore, the real data about what they see and how they feel will be useful for the user-centered design. This paper's objective is to analyze eye-movement recordings and pupil size of user for mobile interface design. For this objective, it was experimented on that the user's eyegaze data of using a mobile phone by the Eyegaze Interface System, and analyzed three levels of user's task performance. The results provided evaluation of new developed and old existing interface design of mobile phone by the experiment of eye-movement recordings and pupil size. The benefit of results is compliment of the limitation of current usability test through visual characteristics of design and qualitative data of user.

• Journal of Convergence for Information Technology
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• v.11 no.1
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• pp.20-27
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• 2021

Eye tracking is one of the NUI technologies, and it finds out where the user is gazing. This technology allows users to input text or control GUI, and further analyzes the user's gaze so that it can be applied to commercial advertisements. In the eye tracking system, the allowable range varies depending on the quality of the image and the degree of freedom of movement of the user. Therefore, there is a need for a method of estimating the accuracy of eye tracking in advance. The accuracy of eye tracking is greatly affected by how the eye tracking algorithm is implemented in addition to hardware variables. Accordingly, in this paper, we propose a method to estimate how many degrees of gaze changes when the pupil center moves by one pixel by estimating the maximum possible movement distance of the pupil center in the image.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.107-112
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• 2008

urpose: This thesis is a study the Night myopia was surveyed by Subjective refraction and Objective refraction (Dark retinoscopy), and analyzed the relationship between them. It also looked at the relation between Night myopia and pupil size. Methods: 82 adult subjects (ages of 19 to 44, 44 males and 38 females) were examined by Subjective refraction and Objective refraction in the light place. Then Night myopia and pupil size were examined by Subjective refraction and Objective refraction in the dark again. The Statistics were analyzed by SPSS (Statistical Package for Social Science). Results: As the subjects became younger, the observed Night myopia was getting higher in both Subjective refraction, $x^2$=219.48 (p<0.01) and Objective refraction, $x^2$=241.98 (p<0.01). The relationship was statistically significant by showing large pupil size, $x^2$=151.74 (p<0.01). In Objective refraction, as pupil size became larger in the dark place, so did Night myopia, $x^2$=84.27 (p<0.01), reaching a statistically significant correlation, however, the correlation was low in Subjective refraction. In Subjective refraction, observed Night myopia was 73%, 64 examples of 88 examples, a standard of 0.96${\pm}$0.4584D in ${\pm}$0.25D, in male examples, and it was 64%, 49 examples of 76 examples, a standard of 1.01${\pm}$0.4509D in ${\pm}$0.25D, in female examples. In Objective refraction, it was 48%, 42 examples of 88 examples, in standard of 0.85${\pm}$0.4651D in ${\pm}$0.25D, in male examples. And it was 71%, 54 examples of 76 examples, in standard of 0.96${\pm}$0.4133D in ${\pm}$0.25D, in female examples. Conclusions: Night myopia which is measured by both methods, observed as $x^2$=265.35 (p<0.01) and showed a large relationship. The correlation between the two refractions suggests that observed night myopia diopter by Subjective refraction could be used as correction of night myopia.

• Journal of the Korean Chemical Society
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• v.39 no.1
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• pp.7-13
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• 1995

The crystal sructures of $X(Ca_{46}Al_{92}Si_{100}O_{384})$ and $Ca_{32}K_{28}-X(Ca_{32}K_{28}Al_{92}Si_{100}O_{384})$ dehydrated at $360^{\circ}C$ and $2{\times}10^{-6}$ Torr have been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd3 at $21(1)^{\circ}C.$ Their structures were refined to the final error indices, R_1=0.096,\;and\;R_2=0.068$ with 166 reflections, and R_1=0.078\;and\;R_2=0.056$ with 130 reflections, respectively, for which I > $3\sigma(I).$ In dehydrated $Ca_{48}-X,\;Ca^{2+}$ ions are located at two different sites opf high occupancies. Sixteen $Ca^{2+}$ ions are located at site I, the centers of the double six rings $(Ca(1)-O(3)=2.51(2)\AA$ and thirty $Ca^{2+}$ ions are located at site II, the six-membered ring faces of sodalite units in the supercage. Latter $Ca^{2+}$ ions are recessed $0.44\AA$ into the supercage from the three O(2) oxygen plane (Ca(2)-O(2)= $2.24(2)\AA$ and $O(2)-Ca(2)-O(2)=119(l)^{\circ}).$ In the structure of $Ca_{32}K_{28}-X$, all $Ca^{2+}$ ions and $K^+$ ions are located at the four different crystallographic sites: 16 $Ca^{2+}$ ions are located in the centers of the double six rings, another sixteen $Ca^{2+}$ ions and sixteen $K^+$ ions are located at the site II in the supercage. These $Ca^{2+}$ ions adn $K^+$ ions are recessed $0.56\AA$ and $1.54\AA$, respectively, into the supercage from their three O(2) oxygen planes $(Ca(2)-O(2)=2.29(2)\AA$, $O(2)-Ca(2)-O(2)=119(1)^{\circ}$, $K(1)-O(2)=2.59(2)\AA$, and $O(2)-K(1)-O(2)=99.2(8)^{\circ}).$ Twelve $K^+$ ions lie at the site III, twofold axis of edge of the four-membered ring ladders inside the supercage $(K(2)-O(4)=3.11(6)\AA$ and $O(1)-K(2)-O(1)=128(2)^{\circ}).$

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.4
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• pp.477-482
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• 2012

Purpose: This study is aimed at finding the conditions of ametropia of adults in the Philippines and the South Korean. Methods: The study objects were 7,695(15,390 eyes) Koreans and 2,256(4,512 eyes) Philippines who visited optic clinics and took refraction test. The distributions of their hypermetropias and myopias about astigmatisms were examined, using the method of equivalent spherical power. When astigmatisms were marked in S-C, cylinder lens diopter and astigmatism axis, presbyopic additions and pupillary distances were analyzed by comparison respectively. Results: Among ametropias of Koreans myopias and hypermetropias were 93.69% and 6.31% respectively and about ametropias of Philippines myopia and hypermetropias were 73.43% and 26.57% respectively. As for spherical equivalent power about Koreans, the results showed that Koreans marked -3.352 D about myopia and Philippines marked -2.213 D about it. There is a gap of -1.139 D between them. About hypermetropia Koreans marked 1.147 D and Philippines, 1.251 D and their gap is 0.104 D. As for ametropia of Koreans there is 49.86% in middle myopia, 32.28% about low myopia, 11.55% about high myopia, and 5.54% about low hypermetropia, 0.75% about middle hypermetropia. As for it about Philippines there is 44.53% in low myopia, 25.11% about middle myopia, 3.79% high myopia and 23.03% low hypermetropia, and 3.51% low hypermetropia respectively. As for cylinder lens there is differences of 0.194 D and 0.22 D between Korean and Philippine for both sexes. Totally Koreans have higher cylinders of 0.175 D than Philippines. As for astigmatism, Koreans have direct astigmatism, inverse astigmatism, and oblique astigmatism in their suffering sequence. As for Philippines, they have direct astigmatism, inverse stigmatism, and oblique astigmatism in their abnormal sequence, and they have higher oblique stigmatism than Koreans. As for presbyopic addition, Philippines have higher distributions than Koreans, and 0.296 D is higher in average. As for pupillary distance, Koreans have longer distance of 0.97 mm in man and 0.63 mm in women than Philippines. Conclusions: As for ametropia, Koreans and Philippines have more myopias than hypermetropias, but Philippines have more rates of hypermetropias than Koreans. And Philippines have more presbyopic additions. Koreans have higher morbidity of inverse astigmatism, and Philippines have higher morbidity of oblique astigmatism comparatively. As for pupillary distance, Koreans have longer length in the body characteristics. This shows that geographical circumstances have much to do with refraction conditions of eyes.

• Journal of The Korean Ophthalmological Society
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• v.59 no.11
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• pp.1049-1055
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• 2018

Purpose: To investigate the factors associated with glaucoma in patients with pseudoexfoliation syndrome by comparing features of the anterior segments and ocular biometry according to the presence or absence of open-angle glaucoma in pseudoexfoliation syndrome. Methods: We analyzed 96 patients (115 eyes) diagnosed as having pseudoexfoliation syndrome in this study. The patients were divided into two groups of simple pseudoexfoliation syndrome (64 patients, 76 eyes) and pseudoexfoliation glaucoma (32 patients, 39 eyes). We compared the age, sex, underlying disease, location of pseudoexfoliative material, iris change, degree of nuclear cataract, pupil dilatation, corneal endothelial cell counts, central corneal thickness, anterior chamber depth, axial length, corneal curvature, and intraocular pressure (IOP). Results: There were no significant differences between the two groups in terms of age (p = 0.694), sex (p = 0.161), diabetes (p = 0.440), hypertension (p = 0.238), pseudoexfoliative material observed in anterior capsule (p = 0.700), pupillary margin (p = 0.210), iris depigmentation (p = 0.526), pupillary ruff loss (p = 0.708), degree of nuclear cataract (p = 0.617), pupil dilatation (p = 0.526), central corneal thickness (p = 0.097), anterior chamber depth (p = 0.283), axial length (p = 0.095), or horizontal and vertical corneal curvature (p = 0.066 and 0.306, respectively). In pseudoexfoliation glaucoma, significantly higher IOP (p = 0.026), a high frequency of membrane formation (p = 0.047), and decreased corneal endothelial cell counts (p = 0.048) were observed. Conclusions: Pseudoexfoliation syndrome with open-angle glaucoma was shown to be associated with high IOP, decreased corneal endothelial cell counts, and a high frequency of membrane formation. Therefore, when such changes are observed in pseudoexfoliation syndrome patients, a higher risk of open-angle glaucoma should be recognized, and careful attentionis required accordingly.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.839-842
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• 2008

본 연구는 LCD 패널에서 시청모드별 사용자의 피로도 차이에 대한 연구이다 LCD 사용에 따른 사용자 피로도에 미치는 영향이 보고되고 있는 것을 감안하여 감성 공학적 방법을 이용하여 시청모드에 따른 사용자 피로도 차이를 분석하였다. 실험은 34명의 대학생을 두 그룹으로 나누어서 같은 동영상 조건에서 각각 영화모드와 표준모드를 60분간 시청하게 하였다. 시청 시의 피로도를 알아보기 위해 생리신호 반응(GSR, PPG, SKT), 눈 움직임(동공의 확대 축소속도, 눈 깜박임률) 및 주관적 피로도(긴장도, 쾌적도, 피로도)를 측정하였다. 그 결과 주관적인 평가와 생리 반응에서 영화모드가 표준모드보다 더 피로감을 유발시키는 것을 확인 할 수 있었다. 눈 움직임 반응에서는 통계적으로 유의한 결과를 얻지 못하였다.