• Transactions on Electrical and Electronic Materials
• /
• v.8 no.6
• /
• pp.255-259
• /
• 2007

We have synthesized $CaS:Eu^{2+}$ phosphor by using a sealing vessel and evaluated its photoluminescence properties. The method using a sealing vessel is simple and economical in comparison with other methods reported up to date. As an activator concentration was increased from 0.1 mol% to 4 mol%, the main emission wavelength of the phosphor was increased from 642 nm to 651 nm due to the crystal field splitting of 5d levels of $Eu^{2+}$ ion. Although the same amount of $Eu_2O_3$ was used, the concentration of the activator ions, which were reduced from $Eu^{3+}\;to\;Eu^{2+}$ and substituted $Ca^{2+}$ ions, was increased with increase of firing temperature. Therefore, the main emission wavelength was also. shifted from 645 nm to 651 nm with increase of firing temperature from $1100^{\circ}C\;to\;1300^{\circ}C$. The critical distance($R_{c1}=20.65\;{\AA}$) between $Eu^{2+}$ ions calculated from the critical concentration was well matched with that($R_{c2}=19.17\;{\AA}$) calculated from the Dexter formula.

• Journal of Korean Ophthalmic Optics Society
• /
• v.16 no.3
• /
• pp.313-317
• /
• 2011

Purpose: This study was to assess prevalence of refractive errors and uncorrected refractive errors in elementary school children in Mokpo and uncorrected refractive errors were to be used as the basic data. Methods: Vision tests were conducted on 400 subjects of 1st~6th grades at 3 elementary schools in Mokpo city, and subjective, objective refraction test were also performed to survey uncorrected refractive errors. Results: The prevalence of myopia was 256, 64% of total subjects, Hyperopia was 21, 5.3%, astigmatism was 19, 4.8%. The prevalence of uncorrected refractive errors were increased as higher grade and more oculus dexter higher than oculus sinister. Conclusions: Vision impairment which need an accurate vision correction for elementary school students requires the regular examination and actively correction in order to protect the elementary school students for basic welfare.

• Journal of Korean Society for Quality Management
• /
• v.49 no.3
• /
• pp.433-446
• /
• 2021

Purpose: The main purpose of this study is to analyze the case of the transparent PET bottle resource circulation project of BYN Black Yak Co., Ltd., present implications, and propose ways to spread it in the future. Methods: In this study, the logic of the Double Diamond Model is applied to analyze the development process of sustainable fashion made from BYN Black Yak Co., Ltd.'s PET Bottle Resource Circulation System. Results: The K-rPET Resource Circulation Project of BYN Black Yak Co., Ltd. is recognized as a best example for its contribution to eco-friendly activities, solving social problems, raising consumer awareness, and sharing recycling habits. Before the plastic bottle becomes a garment, five steps are taken (discharge of PET bottle → collection of PET bottle → recycling of PET bottle → fabrication of yarn → production of the finished product out of the fabric). BYN Black Yak Co., Ltd. has successfully commercialized it by recycling reverse-recovery PET bottles by making solutions to problems that have not been solved at each stage. Conclusion: In addition to efforts to find and strengthen weak links presented in the Theory of Constrains (TOC), it appears to have systematically carried out activities to convert stakeholder discomforts into a package of gain points. As shown in the slogan "We are all in!" the proposal and implementation for the completion of a true environmental system is judged to have truly performed ESG management well for the company's business. ESG management activities at BYN Black Yak Co., Ltd. are expected to continue.

• Korean Journal of Veterinary Service
• /
• v.45 no.3
• /
• pp.221-228
• /
• 2022

Cataracts occur commonly in older dogs, which can lead to partial or complete vision loss. In the present study, a 12-year-old male poodle presented for evaluation of ocular sinister (OS) cataract. This study was a clinical case report on the process of performing surgery using phacoemulsification (PHACO) and the problems that arise in patient diagnosed with OS cataract. In the oculus dexter (OD), the artificial eye was inserted because there was no electroretinography (ERG) response. In the OS, the ERG was 51.6 μV, so operation was performed because the visual pathway function remained. Slit-lamp biomicroscopy of the OS showed complete loss of vision as a hypermature cataract and that the lens was hardened. During the cataract surgery using PHACO, visco-elastic agents were used to maintain the shape of the eyeball, and the PHACO procedure took 3.13 minutes. The hardened lens and visco-elastic agents were removed from the eye through PHACO surgery, and the operation was completed by inserting an intraocular lens (IOL). As a result of managing IOP for 2 months after surgery, it remained stable at a maximum of 19 mmHg, and no postoperative ocular hypertension (POH) occurred. Currently, one year has passed since the operation, and the dog maintains its daily life with its left eye without any problems.

• Tunnel and Underground Space
• /
• v.16 no.2 s.61
• /
• pp.109-134
• /
• 2006

Rocks undergo weathering processes influenced by changing in pressure-temperature condition, atmosphere, underground water, and rainfall. The weathering processes change physical and chemical characteristics of the rocks. Once the rocks are weathered, the characteristics of them are changed and, because of the changing, several disadvantages such as rock slope failures and underground water spouts are can occur. Before we cut a large rock slope, therefore, we must analyze current weathering conditions of rocks and predict weathering processes in the future. Through the results of such analyses, we can judge reinforcement works. In order to comply with such requests, chemical weathering sensitivity analysis which was analyzed from chemical weathering velocities and other characteristics of rocks has been applied in several prior construction works in Korea. But, It is defective to use directly in engineering fields because it was developed for soils(not rocks), it has too mny factors must be considered and the relationships between the factors are not clear, and it is hard to explain the weathering processes in engineering time range. Besides above, because it has been used for isotropic rocks, this method is hard to apply to anisotropic rocks such as sedimentary rocks. Acceding to studies from morphologists (e.g. Oguchi et al., 1994; Sunamura, 1996; Norwick and Dexter, 2002), time dependent strength reduction influenced by weathering shows a negative exponential function form. Appling this relation, one can synthesize the factors which influence the weathering processes to the strength reduction, and get meaningful estimates in engineering viewpoint. We suggest this weathering sensitivity characterization method as a technique that can explain time dependent weathering sensitivity characteristics through strength changes and can directly applied the rock slope design.

• Journal of Broadcast Engineering
• /
• v.23 no.1
• /
• pp.45-52
• /
• 2018

The virtual reality (VR) cartoon is a format of VR contents that leverage the characteristics of webtoons that provides the simple story line and graphical storytelling tools to strategically surmount limitations of VR contents design. The VR cartoon enables people to experience the imaginary three-dimensional space in the webtoon as a real space by the transformation of webtoon contents through VR prototyping. The VR cartoon successfully presents focused environment where people can readily pay attention to the contents without notable motion sickness. People have been familiar with the storytelling strategy in the context of published cartoons and webtoons, likely we've understood the narrative of a movie through the continuous scenes projected in the screen. Indeed, it has been recognized as a popular toolset of communication, where visual images are sequentially delivered by replacing multiple planar spaces to tell a story narrative. While there are discrete panels with the time and space resolution in the graphical cartoons, people can distill a commit closure based on their past experiences. This is a typical "grammar" of the cartoon, which can be extrapolated to the VR cartoon that provides a seminal storytelling strategy. In this article, we review how the storytelling strategy in webtoons has been transformed into that in VR cartoons, and analyze the key components of VR cartoons. We envision that our research can potentially create keystones to produce variety of new VR contents by reflecting various narrative media including cartoon as a 'sequential art'.

• Journal of Korean Ophthalmic Optics Society
• /
• v.15 no.1
• /
• pp.73-78
• /
• 2010

Purpose: The purpose of this study was to examine diurnal variation of accommodation on people whose age are between 35 and 50 years old with frequent alternation of accommodation at period 1 (8:00-10:00), period 2(13:00-15:00) and period 3 (18:00-20:00). Methods: All \04 subjects were separated to nonpresbyopia and incipient presbyopia. Tests were done for amplitude of accommodation, accommodative facility and relative amplitude of accommodation. Results: Both nonpresbyopia and incipient presbyopia had the highest amplitude of accommodation in oculus dexter, oculus sinister and oculus uterque at period 2. In addition, the incipient presbyopia showed the statistical significance of daily change. The nonpresbyopia had the most accommodative facility at period 3 and incipient presbyopia had the most accommodative facility at period 2. Their daily variations were statistically significant. Both nonpresbyopia and incipient presbyopia had the most negative relative accommodation of daily change at period I. Both of them had the most positive relative accommodation at period 2. Conclusions: The incipient presbyopia had the highest amplitude of accommodation, accommodative facility. and positive relative accommodation (except the negative relative accommodation) at period 2.