• Title/Summary/Keyword: Mobility Barrier

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Electrical Properties of TiO2 Thin Film and Junction Analysis of a Semiconductor Interface

  • Oh, Teresa
    • Journal of information and communication convergence engineering
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    • v.16 no.4
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    • pp.248-251
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    • 2018
  • To research the characteristics of $TiO_2$ as an insulator, $TiO_2$ films were prepared with various annealing temperatures. It was researched the currents of $TiO_2$ films with Schottky barriers in accordance with the contact's properties. The potential barrier depends on the Schottky barrier and the current decreases with increasing the potential barrier of $TiO_2$ thin film. The current of $TiO_2$ film annealed at $110^{\circ}C$ was the lowest and the carrier density was decreased and the resistivity was increased with increasing the hall mobility. The Schottky contact is an important factor to become semiconductor device, the potential barrier is proportional to the hall mobility, and the hall mobility increased with increasing the potential barrier and became more insulator properties. The reason of having the high mobility in the thin films in spite of the lowest carrier concentration is that the conduction mechanism in the thin films is due to the band-to-band tunneling phenomenon of electrons.

A Study on the Analysis and Investigation about Barrier-Free in Railroad Facilities (철도시설의 배리어프리 실태조사 및 분석)

  • Noh, Ji-Hye;Kang, Byoung-Keun;Seong, Ki-Chang;Park, Kwang-Jae;Kim, Sang-Woon
    • Journal of The Korea Institute of Healthcare Architecture
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    • v.17 no.3
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    • pp.43-51
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    • 2011
  • The mobility and accessibility enhancement is gradually becoming a global interest due to the growth in the aging population and concerns about people with disabilities. The main purpose of this study is to know the current situation in barrier-free level in railroad facilities in order to allow the mobility handicapped to travel in a safe and convenient manner. The research has started with investigating current situation for the mobility handicapped people and explores the needs of barrier-free facilities. 84 domestic railroad facilities were evaluated based on assessment tool developed from the mobility handicapped act. As a result, the fact that the mobility handicapped experienced limited accessibility due to various types of obstacles in the facilities was discovered. Based on the evaluation, obstacles in the facilities were analyzed and categorized by specific dimensions, users' accessibility, mobility, usability, and clarity (way-finding). This study suggests barrier-free design for passenger facilities focused on train station. Because mobility and accessibility are emphasized in current society, improvement of the mobility handicapped' movement should be considered. Barrier-free design for passenger facilities should be realized throughout comprehending the reasons why these obstacles occur in the facilities not using installation convenience facilities. This study has meaning in finding out the obstacles in each cause of occurrence(accessibility, mobility, usability, and clarity (way-finding)).

Development of the Accessibility Guidelines for Mobility Handicapped Persons in Passenger Ship

  • Kim, Hongtae;Lee, Jong-Gap
    • Journal of Navigation and Port Research
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    • v.36 no.9
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    • pp.763-767
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    • 2012
  • The ratio of the mobility handicapped person is about 25.8% of the total population in Korea(MCT, 2006). In order to prepare for the enforcement of the "Transportation Services Improvement Act for the Mobility Handicapped People"(MCT, 2006), various equipments and installations should be developed to ensure appropriate safety level for the mobility handicapped persons in maritime transportation. While approximately 10 million people are using domestic passenger vessels annually, preferences for maritime transport is very low, especially for the mobility handicapped. This study reviewed a current status of the mobility handicapped person in domestic passenger ship and analysed the improvement plan for them. To investigate the current status of domestic passenger vessel usage by the mobility handicapped, to analysis the requirements for amenities necessary for the mobility handicapped and select the ones to be developed based on the investigated results and to do feasibility study of barrier-free ship.

Effect of Double Schottky Barrier in Gallium-Zinc-Oxide Thin Film

  • Oh, Teresa
    • Transactions on Electrical and Electronic Materials
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    • v.18 no.6
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    • pp.323-329
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    • 2017
  • This reports the electrical behavior, bonding structure and Schottky contact of gallium-zinc-oxide (GZO) thin film annealed at $100{\sim}400^{\circ}C$. The mobility of GZO with high density of PL spectra and crystal structure was also increased because of the structural matching between GZO and Si substrate of a crystal structure. However, the GZO annealed at $200^{\circ}C$ with an amorphous structure had the highest mobility as a result of a band to band tunneling effect. The mobility of GZO treated at low annealing temperatures under $200^{\circ}C$ increased at the GZO with an amorphous structure, but that at high temperatures over $200^{\circ}C$ also increased when it was the GZO of a crystal structure. The mobility of GZO with a Schottky barrier (SB) was mostly increased because of the effect of surface currents as well as the additional internal potential difference.

Clinical comparison of resorbable and nonresorbable Barrier in guided tissue regeneration of human intrabony defects (흡수성 차폐막을 이용한 조직유도재생술의 임상적 효과)

  • Hur, Yin-Shik;Kwon, Young-Hyuk;Lee, Man-Sup;Park, Joon-Bong;Herr, Yeek
    • Journal of Periodontal and Implant Science
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    • v.29 no.1
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    • pp.193-207
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    • 1999
  • The purpose of this study was to compare the clinical results of guided tissue regeneration(GTR) using a resorbable barrier manufactured from an copolymer of polylactic acid (PLA) and polylaetic-glycolic acid(PLGA) with those of nonresorbable ePTFE barrier. Thirty two patients(25 to 59 years old) with one radiographically evident intrabony lesion of probing depth ${\geq}$6mm participated in a 6-month controlled clinical trial. The subjects were randomly divided into three independent groups. The first group(n=8) received a ePTFE barrier. The second group (n=12) received a resorbable PLA/PLGA barrier. The third group (n=12) received a resorbable PLA/PLGA barrier combined with an alloplastic bone graft. Plaque index (PI), gingival index(GI), probing depth(PD), gingival recession, clinical attachment level(CAL), and tooth mobility were recorded prior to surgery and at 3, 6 months postsurgery, Statistical tests used to analyze these data included independent t-test, paired t-test, one-way ANOVA. The results were as follows : 1. Probing depth was significantly reduced in all groups at 3, 6 months postsurgery and there were not significant differences between groups. 2. Clinical attachment level was significantly increased in all groups at 3, 6 months postsurgery and there were not significant differences between groups. 3. There were not significant differences in probing depth, clinical attachment level, gingival recession, tooth mobility between second group (PLA/PLGA barrier) and third group (PLA/PLGA barrier combined with alloplastic bone graft) 4. Tooth mobility was not significantly increased in all groups at 3, 6 months postsurgery and there were not significant differences between groups. In conclusion, PLA/PLGA resorbable barrier has similar clinical potential to eP'IFE barrier in GTR procedure of intrabony pockets under the present protocol.

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High Temperature Electrical Behavior of 2D Multilayered MoS2

  • Lee, Yeon-Seong;Jeong, Cheol-Seung;Baek, Jong-Yeol;Kim, Seon-Guk
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.377-377
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    • 2014
  • We demonstrate the high temperature-dependent electrical behavior at 2D multilayer MoS2 transistor. Our previous reports explain that the extracted field-effect mobility of good device was inversely proportional to the increase of temperature. Because scattering mechanism is dominated by phonon scattering at a well-designed MoS2 transistor, having, low Schottky barrier. However, mobility at an immature our $MoS_2$ transistor (${\mu}m$ < $10cm^2V^{-1}s^{-1}$) is proportional to the increase temperature. The existence of a big Schottky barrier at $MoS_2-Ti$ junction can reduce carrier transport and lead to lower transistor conductance. At high temperature (380K), the field-effect mobility of multilayer $MoS_2$ transistor increases from 8.93 to $16.9cm^2V^{-1}sec^{-1}$, which is 2 times higher than the value at room temperature. These results demonstrate that carrier transport at an immature $MoS_2$ with a high Schottky barrier is mainly affected by thermionic emission over the energy barrier at high temperature.

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Current Density Equations Representing the Transition between the Injection- and Bulk-limited Currents for Organic Semiconductors

  • Lee, Sang-Gun;Hattori, Reiji
    • Journal of Information Display
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    • v.10 no.4
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    • pp.143-148
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    • 2009
  • The theoretical current density equations for organic semiconductors was derived according to the internal carrier emission equation based on the diffusion model at the Schottky barrier contact and the mobility equation based on the field dependence model, the so-called "Poole-Frenkel mobility model." The electric field becomes constant because of the absence of a space charge effect in the case of a higher injection barrier height and a lower sample thickness, but there is distribution in the electric field because of the space charge effect in the case of a lower injection barrier height and a higher sample thickness. The transition between the injection- and bulk-limited currents was presented according to the Schottky barrier height and the sample thickness change.

Value Analysis of Barrier-free Facilities at Subway Stations Using CVM with a Double Bounded Dichotomous Choice Question (이중양분선택형 질문법을 이용한 CVM에 의한 지하철 역사 Barrier-free 시설의 가치분석)

  • Jung, Hun-Young;Baik, Sang-Keun;Baek, Eun-Sang
    • Journal of Korean Society of Transportation
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    • v.26 no.5
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    • pp.205-216
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    • 2008
  • As the aged and physically disabled people are expected to increase in the next several years, traffic demand especially for the 'mobility handicapped people' will be stronger. According to this trend, our society needs the improvement of social overhead capital for the aged and the disabled. First of all, Barrier-free of public transport facilities is urgent case. The purpose of this study is to estimate value of the Barrier-free facilities at subway stations by using Contingent Valuation Method(CVM) with Double Bounded Dichotomous Choice Question and to analyze the factor which affects the WTP(Willingness To Pay) of subway users by using Survival Analysis. As a result of this study, 'Elevators' and 'Escalators' are higher than 'Handicapped Gate Machines' and 'Ramps for Wheelchair' in the aspect of the average willingness to pay. Therefore the government is recommended to install the Barrier-free facilities for going up and down such as 'Elevators' and 'Escalators', and then supply others for just using subway, and passing such as 'Handicapped Gate Machines' and 'Ramps for Wheelchair'. Also, the average willingness to pay of 'mobility handicapped people' is higher than that of 'normal people'. It indicates that 'mobility handicapped people' value each Barrier-free facility high compared to 'normal people'.

Optimized Path Finding Algorithm for Walking Convenience of the People with Reduced Mobility (교통약자의 이동편의를 위한 최적경로 탐색 기법)

  • Moon, Mikyeong;Lee, Youngmin;Yu, Kiyun;Kim, Jiyoung
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.34 no.3
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    • pp.273-282
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    • 2016
  • There has been growing social interest recently in the movement rights of people with reduced mobility. However, it simply eliminates the temporary inconvenience of walking of people with reduced mobility because it focuses only on supply of institutional facilities. Therefore, we look forward to improving movement welfare by proposing an optimized path finding algorithm for people with reduced mobility that takes into consideration physical elements affecting their movement, such as slope, steps etc. We selected Walking barrier factor by analyzing previous studies and calculated the relative importance of Walking barrier factors using an Analytic Hierarchy Process(AHP). Next, through the fuzzy system, the Walking disturbance level of link, which integrates the weights of Walking barrier factors and the attributes of each link, is derived. Then, Walking path cost that takes into consideration the ‘length’ factors is calculated and an optimized path for people with reduced mobility is searched using Dijkstra’s Algorithm. Nineteen different paths were searched and we confirmed that the derived paths are meaningful in terms of improving the mobility of people with reduced mobility by conducting a field test. We look forward to improving movement welfare by providing a navigation service using the path finding algorithm proposed in this study.

Study on GZO Thin Films as Insulator, Semiconductor and Conductor Depending on Annealing Temperature (열처리 온도에 따라서 절연체, 반도체, 전도체의 특성을 갖는 GZO 박막의 특성연구)

  • Oh, Teresa
    • Korean Journal of Materials Research
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    • v.26 no.6
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    • pp.342-346
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    • 2016
  • To observe the bonding structure and electrical characteristics of a GZO oxide semiconductor, GZO was deposited on ITO glasses and annealed at various temperatures. GZO was found to change from crystal to amorphous with increasing of the annealing temperatures; GZO annealed at $200^{\circ}C$ came to have an amorphous structure that depended on the decrement of the oxygen vacancies; increase the mobility due to the induction of diffusion currents occurred because of an increment of the depletion layer. The increasing of the annealing temperature caused a reduction of the carrier concentration and an increase of the bonding energy and the depletion layer; therefore, the large potential barrier increased the diffusion current dna the Hall mobility. However, annealing temperatures over $200^{\circ}C$ promoted crystallinity by the defects without oxygen vacancies, and then degraded the depletion layer, which became an Ohmic contact without a potential barrier. So the current increased because of the absence of a potential barrier.