• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.3
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• pp.207-212
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• 2019

A flat-type piezoelectric ceramic ultrasonic transmitter was successfully fabricated for application in acoustic devices with cone-free diaphragms. The transmitter, possessing a center frequency of 40.6 kHz, exhibited a higher displacement characteristic for a multilayer type compared with a single layer type. Surface roughness treatment of an Al elastic diaphragm influenced a slight increase (1.1 dB) in the sound pressure level (SPL) at $10V_{rms}$ due to the enlarged surface area. The fabricated multilayer piezoelectric ceramic ultrasonic transmitter showed increasing SPL with increasing input voltage, with a maximum SPL of approximately 123.6 dB at $10V_{rms}$. This implies a doubly increased SPL density of $3.6dB/mm^3$, superior to that of a commercial open-type transmitter with a cone.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.2852-2858
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• 2022

A proton therapy facility is under development at Huazhong University of Science and Technology (HUST). To meet the need for fast energy changes during treatments, a beamline control system (BCS) has been designed and implemented. The BCS coordinates and controls various beamline devices by adopting a distributed architecture divided into three layers: the client, server, and device layers. Among these, the design of the server layer is the key to realize fast energy changes. The server layer adopts the submodule programming paradigm and optimizes the data interface among modules, allowing the main workflow to be separated from the device workflow and data. Furthermore, this layer uses asynchronous, multithreaded, and thread-locking methods to improve the system's ability to operation efficiently and securely. Notably, to evaluate the changing energy status over time, a dynamic node update method is adopted, which can dynamically adjust the update frequency of variable nodes. This method not only meets the demand for fast updates on energy changes but also reduces the server's communication load in the steady state. This method is tested on a virtual platform, and the results are as expected.

• The Journal of the Convergence on Culture Technology
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• v.9 no.2
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• pp.483-491
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• 2023

Due to the spread of mobile devices, the use of mobile electronic notification services is increasing. For the mobile electronic notification service, the connecting information is required to identify the owner of the mobile device and the recipient of the notification. The connecting information is an online resident registration number, and safe management is essential. Therefore, in this paper, the processing flow, interconnecting standard, and management plan are proposed when a mobile electronic notification requesting agency requests the identity verification agency to convert the resident registration number of the recipient of the electronic notification to connecting information. In the proposed method, it is suggested that a safe mobile electronic notification service is possible by defining the process of collective conversion of connecting information between private organizations and personal identity proofing agency, information transmission and reception methods, and interworking standards.

• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.559-569
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• 2022

Due to the spread of mobile devices, the use of mobile electronic notification services is increasing. For the mobile electronic notification service, the connecting information is required to identify the owner of the mobile device and the recipient of the notification. The connecting information is an online resident registration number, and safe management is essential. Therefore, in this paper, the processing flow, interconnecting standard, and management plan are proposed when a mobile electronic notification requesting agency requests the identity verification agency to convert the resident registration number of the recipient of the electronic notification to connecting information. In the proposed method, it is suggested that a safe mobile electronic notification service is possible by defining the process of collective conversion of connecting information between private organizations and personal identity proofing agency, information transmission and reception methods, and interworking standards.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.4
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• pp.445-450
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• 2024

The expansion of lithium-ion battery usage beyond portable electronic devices to electric vehicles and energy storage systems is driven by their high energy density and favorable cycle characteristics. Enhancing the stability and performance of these batteries involves exploring solid electrolytes as alternatives to liquid ones. While sulfide-based solid electrolytes have received significant attention for commercialization, research on amorphous-phase glass solid electrolytes in oxide-based systems remains limited. Here, we investigate the glass transition temperatures and sintering behaviors by changing the molecular ratio of Li₂O/B₂O₃ in borate glass comprising Li₂O-B₂O₃-Al₂O₃ system. The glass transition temperature is decreasing as increasing the amount of Li₂O. When we sintered at 450℃, just above the glass transition temperature, the samples did not consolidate well, while the proper sintered samples could be obtained under the higher temperature. We successfully obtained the borate glass ceramics phases by melt-quenching method, and the sintering characteristics are investigated. Future studies could explore optimizing ion conductivity through refining processing conditions, adjusting the glass former-to-modifier ratio, and incorporating additional Li salt to enhance the ionic conductivity.

• Journal of IKEEE
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• v.28 no.3
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• pp.369-374
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• 2024

This paper addresses the design optimization of capacitorless DRAM(one-transistor DRAM., 1T-DRAM), which has gained attention as a next-generation memory technology. To overcome the limitations of conventional capacitor-based DRAM, an asymmetric dual-gate structure is proposed to enhance retention time and overall performance. The zero-temperature coefficient (ZTC) point is set at 1.25 V to minimize performance degradation due to temperature variations. Current-voltage characteristics were analyzed at various temperatures (300K-400K), confirming stable memory operation at the ZTC point, even under temperature fluctuations. The proposed design demonstrates reliable operation at high temperatures, proving the potential for high-efficiency, highly reliable memory technology. As a result, the 1T-DRAM device can make a significant contribution to the development of next-generation memory devices.

• Journal of radiological science and technology
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• v.39 no.2
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• pp.171-176
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• 2016

The quality assurance (QA) is very important for diagnostic field and radiation therapy field to evaluate the characteristic of devices. The purpose of this study was to compare different NPS methodologies results which are measuring NPS with regard to horizontal and vertical directions by using megavoltage X-ray energies. The NPS evaluation methods were applied to the International Electro-technical Commission standard (IEC 62220-1). The electronic portal imaging devices (EPID) devices such as Siemens BEAMVIEW$^{PLUS}$, Elekta iViewGT and Varian Clinac$^R$ iX aS1000 were used. NPS data were expressed by corresponding each frequency about average of noise value corresponding the each frequency, and NPS were evaluated quantitatively by totaling up the noise values of average frequency which are on horizontal and vertical directions. In NPS results for Elekta iViewGT, NPS of horizontal and vertical by using 4 methods were indicated the difference of 3~5% between horizontal and vertical direction. In the results of Siemens BEAMVIEW$^{PLUS}$ and Varian Clinac$^R$ iX aS1000, the NPS of horizontal and vertical direction were indicated the difference of 15% when averaging the whole values. This study were evaluated the NPS of each devices by totaling up the noise values of average frequency which are on horizontal and vertical directions suggesting the quantitative evaluation method using the data.

• Journal of Convergence for Information Technology
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• v.10 no.9
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• pp.28-34
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• 2020

In this paper, an optical sensor based on an AZO semiconductor material is fabricated on an OHP film with high transmittance, and the characteristics of the optical element and the properties of the semiconductor material are described. In order to realize a flexible optical device, which is a major issue in the field of near-electronic devices, a transparent and bendable OHP film was used as a substrate. In addition, ITO, which is used for mass production as a transparent electrode and a semiconductor material, is expensive due to the scarcity of indium. Therefore, it is necessary to find a material that can replace it. The optical and electrical properties of the Au/Al/AZO/OHP structure are implemented to evaluate whether AZO is possible. It was found that devices and materials had no characteristic change by bending, and these results provide a possibility for application to a next-generation device. However, it is necessary to remove fine scratches on the surface of the OHP film, as well as optimized devices based on materials and structures that can improve the photocurrent.

• Journal of Korean Clinical Health Science
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• v.5 no.2
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• pp.834-849
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• 2017

Purpose: The aim of this study is to examine the trends of cataract surgery and the recognition of cataract. Methods: ; It enrolled a total of 150 respondents, comprising 72 men and 78 women, who reside in Busan Metropolitan City, Ulsan Metropolitan City and Kyeong-nam Province. By the age groups, they include 44 people in their 20s, 24 in their 30s, 24 in their 40s, 26 in their 50s and 32 aged 60 years or older. In addition, the current study was conducted by dividing the respondents into two groups: people with cataract or not. Moreover, it was also conducted mainly for younger people. Results: 1. As for age of cataract operation, this study say that 1 patient was in their 20s, 3 patients in their 30s, 3 patients in their 40s, 6 patients in their 50s, and 7 patients in their over 60s. 2. In the question about whether they know about cataract, 100 respondents answered 'I know', 50 answered 'I do not know', 67% answered 'I know', 33% answered 'I do not know'. 3. As for pathways to know about cataract, of the total 120 respondents, 49 (41%) were in the media, 20 (17%) were Internet users, 26 (22%) were acquaintances, and 10 (7%) were specialty books, and 15 (13%) were 'others'. 4. As for cataract causes, 20 respondents (13%) answered 'exposure to sunlight', 12 (8%) answered 'electronic devices', 7 answered 'hereditary' 89 (60%) answered, and 22 (14%) answered 'eye disease'. 5. Twenty (13%) answered 'extremely yes', 40 (27%) answered 'yes', and 31 (21%) answered 'normal' when asked whether the use of smartphone was affected by cataracts. 48 (32%) answered 'little', and 11 (7%) answered 'not at all'. Our results showed that many people aged 50 years or older developed cataract and received surgery. It was also shown, however, that people in their 20s to 40s also developed cataract and received surgery. Conclusions: Our eyes are exposed to many places. Many people are unaware of cataracts, despite the fact that cataracts are gradually getting younger, due to the development of electronic devices and the use of electrical appliances. We should have interest in many information and contents about cataracts, knowing the importance to eyes, and gradually reducing the use of many electronic devices in young people.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.151-151
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• 2009

Recently, there has been increasing interest in amorphous oxide semiconductors to find alternative materials for an amorphous silicon or organic semiconductor layer as a channel in thin film transistors(TFTs) for transparent electronic devices owing to their high mobility and low photo-sensitivity. The fabriction of amorphous oxide-based TFTs at room temperature on plastic substrates is a key technology to realize transparent flexible electronics. Amorphous oxides allows for controllable conductivity, which permits it to be used both as a transparent semiconductor or conductor, and so to be used both as active and source/drain layers in TFTs. One of the materials that is being responsible for this revolution in the electronics is indium-zinc-tin oxide(IZTO). Since this is relatively new material, it is important to study the properties of room-temperature deposited IZTO thin films and exploration in a possible integration of the material in flexible TFT devices. In this research, we deposited IZTO thin films on polyethylene naphthalate substrate at room temperature by using magnetron sputtering system and investigated their properties. Furthermore, we revealed the fabrication and characteristics of top-gate-type transparent TFTs with IZTO layers, seen in Fig. 1. The experimental results show that by varying the oxygen flow rate during deposition, it can be prepared the IZTO thin films of two-types; One a conductive film that exhibits a resistivity of $2\times10^{-4}$ ohm${\cdot}$cm; the other, semiconductor film with a resistivity of 9 ohm${\cdot}$cm. The TFT devices with IZTO layers are optically transparent in visible region and operate in enhancement mode. The threshold voltage, field effect mobility, on-off current ratio, and sub-threshold slope of the TFT are -0.5 V, $7.2\;cm^2/Vs$, $\sim10^7$ and 0.2 V/decade, respectively. These results will contribute to applications of select TFT to transparent flexible electronics.