Linear electric generator with Halbach array to self-charge a smartphone

Cellular phones have not only function to communicate, but also have e-banking, web surfing, music, and entertainment. The performance of the smartphone has improved because of various functions of smartphone, and capacity of battery has also improved gradually. Although smartphone batteries have been improved compared to conventional batteries, the available usage time of a phone’s rechargeable battery is getting shorter because of the demands of various applications. Therefore, we propose a new tubular permanent magnet linear generator that uses a Halbach array, to send a message or emergency call when the battery is discharged. In order to increase the power generation of existing tubular linear generators, we changed the axial-direction permanent magnet array to a Halbach-type array. When using the Halbach array, it is possible to generate a strong magnetic field without additional magnetic material. In this research, we compared the Halbach array that uses axially and radially magnetized permanent magnets with an existing model that uses an axially magnets. We verified improvement in the amount of power generated with no-load analysis through simulation using the Maxwell commercial electromagnetic analysis software

Approaches to Stretchable Polymer Active Channels for Deformable Transistors

The fabrication of deformable devices has been explored by interconnecting nonstretchable unit devices with stretchable conductors or by developing stretchable unit devices consisting of all stretchable device components such as electrodes, active channels, and dielectric layers. Most researches have followed the first approach so far, and the researches based on the second approach are at the very beginning stage. This paper discusses the perspectives of the second approach, specifically focusing on the polymer semiconductor channel layers, that is expected to facilitate high density device integration in addition to large area devices including polymer solar cells and light-emitting diodes. Three different routes are suggested as separate sections according to the principles imparting stretchability to polymer semiconductor layers: structural configurations of rigid semiconductors, two-dimensional network structure of semiconductors on elastomer substrates, and ductility enhancement of semiconductor films. Each section includes two subsections divided by the methodological difference. This Perspective ends with discussion on the future works for the routes and the challenges related to other device components.112417Ysciescopu

Linear electric generator with Halbach array to self-charge a smartphone

Cellular phones have not only function to communicate, but also have e-banking, web surfing, music, and entertainment. The performance of the smartphone has improved because of various functions of smartphone, and capacity of battery has also improved gradually. Although smartphone batteries have been improved compared to conventional batteries, the available usage time of a phone’s rechargeable battery is getting shorter because of the demands of various applications. Therefore, we propose a new tubular permanent magnet linear generator that uses a Halbach array, to send a message or emergency call when the battery is discharged. In order to increase the power generation of existing tubular linear generators, we changed the axial-direction permanent magnet array to a Halbach-type array. When using the Halbach array, it is possible to generate a strong magnetic field without additional magnetic material. In this research, we compared the Halbach array that uses axially and radially magnetized permanent magnets with an existing model that uses an axially magnets. We verified improvement in the amount of power generated with no-load analysis through simulation using the Maxwell commercial electromagnetic analysis software

Linear electric generator with Halbach array to self-charge a smartphone

Cellular phones have not only function to communicate, but also have e-banking, web surfing, music, and entertainment. The performance of the smartphone has improved because of various functions of smartphone, and capacity of battery has also improved gradually. Although smartphone batteries have been improved compared to conventional batteries, the available usage time of a phone’s rechargeable battery is getting shorter because of the demands of various applications. Therefore, we propose a new tubular permanent magnet linear generator that uses a Halbach array, to send a message or emergency call when the battery is discharged. In order to increase the power generation of existing tubular linear generators, we changed the axial-direction permanent magnet array to a Halbach-type array. When using the Halbach array, it is possible to generate a strong magnetic field without additional magnetic material. In this research, we compared the Halbach array that uses axially and radially magnetized permanent magnets with an existing model that uses an axially magnets. We verified improvement in the amount of power generated with no-load analysis through simulation using the Maxwell commercial electromagnetic analysis software

Linear electric generator with Halbach array to self-charge a smartphone

Cellular phones have not only function to communicate, but also have e-banking, web surfing, music, and entertainment. The performance of the smartphone has improved because of various functions of smartphone, and capacity of battery has also improved gradually. Although smartphone batteries have been improved compared to conventional batteries, the available usage time of a phone’s rechargeable battery is getting shorter because of the demands of various applications. Therefore, we propose a new tubular permanent magnet linear generator that uses a Halbach array, to send a message or emergency call when the battery is discharged. In order to increase the power generation of existing tubular linear generators, we changed the axial-direction permanent magnet array to a Halbach-type array. When using the Halbach array, it is possible to generate a strong magnetic field without additional magnetic material. In this research, we compared the Halbach array that uses axially and radially magnetized permanent magnets with an existing model that uses an axially magnets. We verified improvement in the amount of power generated with no-load analysis through simulation using the Maxwell commercial electromagnetic analysis software

High performance gas sensor platform based on integrated sensing mechanisms

We introduce a gas sensor platform consisting of resistive sensor, thin film transistor (TFT) type sensor, and Si-based field effect transistor (FET) type sensor fabricated on the same wafer. The FET type sensor has a horizontal floating gate interdigitated with the control gate. The schematic structures of these gas sensors are shown in Fig. 1. These gas sensors can be fabricated using only 5 masks. The sensing layer of these sensors is a 15nm thick n-type ZnO film prepared using atomic layer deposition (ALD) in the final process step. Although these sensors have the same sensing material, they have different sensing characteristics because of different sensing mechanisms. Our group has reported the studies of resistive- and FET-type gas sensors having ALD ZnO sensing layer previously [1], [2]. Fig. 2 shows the transfer (I-V) characteristics of these sensors. These sensors have different sensing characteristics when exposed to 500 ppb of oxidizing gas, NO2. When exposed to NO2 gas, the currents of resistive- and TFT-type gas sensors are decreased [2]. On the other hand, the drain current of the FET-type gas sensor increases when exposed to NO2 gas [1], [2]. As a result, the difference in response of these sensors can be used as a fingerprint to more accurately detect the target gas in the gas sensor platform composed of three types of gas sensors. Please click Additional Files below to see the full abstract

Recovery of off-state stress-induced damage in FET-type gas sensor using self-curing method

The need for high-performance gas sensors is driven by concerns over indoor and outdoor air quality, and industrial gas leaks. Due to their structural diversity, vast surface area, and geometric tunability, metal oxides show significant potential for the development of gas sensing systems. Despite the fact that several previous reports have successfully acquired a suitable response to various types of target gases, it remains difficult to maintain the reliability of metal oxide-based gas sensors. In particular, the degradation of the sensor platform under repetitive operation, such as off-state stress (OSS) causes significant reliability issues. We investigate the impact of OSS on the gas sensing performances, including response, low-frequency noise, and signal-to-noise ratio of horizontal floating-gate field-effect-transistor (FET)-type gas sensors. The 1/f noise is increased after the OSS is applied to the sensor because the gate oxide is damaged by hot holes. Therefore, the SNR of the sensor is degraded by the OSS. We applied a self-curing method based on a PN-junction forward current at the body–drain junction to repair the damaged gate oxide and improve the reliability of the sensor. It has been demonstrated that the SNR degradation caused by the OSS can be successfully recovered by the self-curing method

Analysis on Steering Performance of Active Steering Bogie According to Steering Angle Control on Curved Section

In this paper, prior to the commercialization of a developed active steering bogie, we want to analyze steering performance experimentally according to steering angle level with the aim of obtaining steering performance data to derive practical design specifications for a steering system. In other words, the maximum steering performance can be obtained by controlling the steering angle at the 100% level of the target steering angle, but it is necessary to establish the practical control range in consideration of the steering system cost increase, size increase, and consumer steering performance requirements and commercialize. The steering control test using the active steering bogie was conducted in the section of the steep curve with a radius of curvature of R300, and steering performance such as bogie angle, wheel lateral force, and derailment coefficient were analyzed according to the steering angle level. As the steering angle level increased, the bogie indicated that it was aligned with the radial steering position, and steering performance such as wheel lateral force and derailment coefficient was improved. The steering control at 100% level of the target steering angle can achieve the highest performance of 83.6% reduction in wheel lateral force, but it can be reduced to about one-half of the conventional bogie at 25% level control and about one-third at 50% level. Considering cost rise by adopting the active steering system, this result can be used as a very important design indicator to compromise steering performance and cost rise issues in the design stage of the steering system from a viewpoint of commercialization. Therefore, it is expected that the results of the steering performance experiment according to the steering angle level in this paper will be used as very useful data for commercialization

Projecting Lifetime Health Outcomes and Costs Associated with the Ambient Fine Particulate Matter Exposure among Adult Women in Korea

We sought to estimate the lifetime healthcare costs and outcomes associated with the exposure to the escalated concentration of fine particulate matter (particle size < 2.5 μm, PM2.5) among adult Korean women. We adapted a previously developed Markov model, and a hypothetical cohort composed of Korean women was exposed to either a standard (15 μg/m3) or increased (25 μg/m3) concentration of PM2.5. The time horizon of the analysis was 60 years, and the cycle length was 1 year. The outcomes were presented as direct healthcare costs and quality-adjusted life years (QALYs), and costs were discounted annually at 5%. Deterministic and probabilistic sensitivity analyses were performed. The model estimated that when the exposure concentration was increased by 10 μg/m3, the lifetime healthcare cost increased by USD 9309, which is an 11.3% increase compared to the standard concentration group. Women exposed to a higher concentration of PM2.5 were predicted to live 30.64 QALYs, compared to 32.08 QALYs for women who were exposed to the standard concentration of PM2.5. The tendency of a higher cost and shorter QALYs at increased exposure was consistent across a broad range of sensitivity analyses. The negative impact of PM2.5 was higher on cost than on QALYs and accelerated as the exposure time increased, emphasizing the importance of early intervention