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Implication of Surface Passivation on the In-Plane Charge Transport in the Oriented Thin Films of P3HT
Get PDFOptimizing charge transport in organic semiconductors is crucial for advancing next-generation optoelectronic devices. The performance of organic field-effect transistors (OFETs) is significantly influenced by the alignment of films in the channel direction and the quality of the dielectric surface, which should be uniform, smooth, and free of charge-trapping defects. Our study reports the enhancement of OFET performance using large-area, uniform, and oriented thin films of regioregular poly[3-hexylthiophene] (RR-P3HT), prepared via the Floating Film Transfer Method (FTM) on octadecyltrichlorosilane (OTS) passivated SiO2 surfaces. SiO2 surfaces inherently possess dangling bonds that act as charge traps, but these can be effectively passivated through optimized surface treatments. OTS treatment has improved the optical anisotropy of thin films and the surface wettability of SiO2. Notably, using octadecene as a solvent during OTS passivation, as opposed to toluene, resulted in a significant enhancement of charge carrier transport. Specifically, passivation with OTS-F (10 mM OTS in octadecene at 100 °C for 48 h) led to a >150 times increase in mobility and a reduction in threshold voltage compared to OTS-A (5 mM OTS in toluene for 12 h at room temperature). Under optimal conditions, these FTM-processed RR-P3HT films achieved the best device performance, with a saturated mobility (μsat) of 0.18 cm2V−1s−1.journal articl
色素増感太陽電池におけるコスト削減と耐久性向上に向けたアプローチ
Get PDF九州工業大学博士（工学）九州⼯業⼤学博⼠学位論⽂ 学位記番号：生工博甲第503号 学位授与年⽉⽇: 令和7年3⽉25⽇令和6年度doctoral thesi
High Pulse Current IGBT Power Module for MRM Drive
Get PDFThe Magnet Reversal Motor (MRM) is an innovative motor to achieve substantial reduction of conduction loss in Cu wire by employing magnetization reversal principle by high magnetic flux pulse in the stator. MRM has significant advantages over conventional motors in energy efficiency in low rpm range which the conventional motor has the problem of lowering in the efficiency. This paper presents newly developed IGBT power module with very low profile to MRM high flux generation. In a single PCB based module consists of a full-bridge with isolated gate drivers as well as a DC-link capacitor. Several PCBs are installed on top of each other as multi-cascade flux pulse generation (MCMF) in order to integrate the drive circuits compactly. These designed PCB s were used to demonstrated to generate 1-2T flux density required to drive the MRM.journal articl
Job Hunting of International Students with Intermediate Level of Japanese at Engineering Graduate School: An Interview Survey to Explore the Possibility of Japanese Language Education for Supporting their Job Search Activities
Get PDF本稿は日本語が中級レベルにある工学系大学院留学生を研究対象とし、彼らに対する就職支援を目的とした日本語教育の可能性を探るために実施した調査について報告するものである。調査では日本の就職活動経験者３名に対しACTFL-OPIによる口頭運用能力テストと半構造化インタビューを実施した。ACTFL-OPIからは３名が高い伝達技能を有することが示唆された。インタビューでは、就職活動と日本語学習に関して尋ねた結果、内定獲得に繋がったと推測される要素として「就職活動における自分の立ち位置を把握し、行動する」「周囲の協力を得る」等を挙げることができた。以上の調査結果を基に、本研究の対象者向けの日本語教育において、「日本語を使用しようとする姿勢を養う」「専門関連の話題について日本語で表現する」等が重要であることを指摘し、初級レベルから就職関連の話題を取り入れるといった日本語教育の方法を提案した。journal articl
Economic Impacts of Tariff Reductions in the Greater Mekong Subregion: Effects of Data Aggregation in the GTAP Model under Three Development Scenarios
Get PDFThe Greater Mekong Subregion (GMS) comprising Lao-PDR, China, Cambodia, Myanmar, Vietnam, and Thailand is experiencing economic transformations driven by growth rate shifts and policy changes, such as Free Trade Agreements. In this regard, the study utilizes the Global Trade Analysis Project Recursive Dynamic (GTAP-RD) model to analyze economic growth and the impact of Free Trade Agreements (FTAs) on the economies within this subregion. Policy changes are assessed within the context of evolving trade barriers and growth rates, including tariff rates, demographic trends, labor market evolutions, and Gross Domestic Product (GDP) fluctuations. By employing multiple scenarios, this research assesses the uncertainties in future economic projections and compares these scenarios to clarify the potential economic possibilities. We compared the outcomes of the GTAP-RD model across three different sector aggregation schemes – 10, 23, and 49 sectors – to understand how sector aggregation affects economic modeling. We observed that finer sector aggregations tend to reveal more granular details of disparities.
Conversely, coarser aggregations gloss over some details but provide a general view and capture broader economic trends.journal articl
A robust 3D position estimation and tracking method of multiple fish for occlusion and mirror image in a small tank
Get PDFAnimal populations exhibit adaptive changes in response to stimuli. A time series of individual positions and poses must be tracked to reveal collective animal behavior. Tracking fish in 3D space is needed, especially for fish. However, tracking in camera images involves the difficulties of occlusions and mirror images. This study uses three cameras to propose a robust 3D position estimation and tracking method of multiple fish for occlusion and mirror image in a small tank. Fish occlusion occurring in one direction is handled by estimating the 3D position using results from the other two directions. DeepLabCut for multiple animals (maDLC) finds fish feature points for each camera view. Post-processing performs for proper correspondence between feature points and individuals: Removing misassignments, matching the feature point in all camera views, and merging feature points representing the same fish. Feature points are estimated in 3D, and if their centroid is outside of the tank, they are eliminated as mirror images. Experimental results showed that even if fish occlusion occurred in one direction, 3D position estimation could be performed if feature points were estimated in the other two directions using the proposed method. Mirror images were eliminated, and the actual fish could be tracked.journal articl
Developing a device to determine the permeation of chemicals through whole protective boots
Get PDFObjectives
To develop a device to evaluate the permeation resistance of chemical-protective boots continuously in contact with liquid chemicals, and to compare the permeation time of the component material test pieces with the permeation time of the whole boot and thus evaluate its performance.
Methods
The permeation time was calculated for toluene, dichloromethane, and acetone in 4 types of boot, according to Japanese Industrial Standard (JIS) T 8117:2005.
Results
The permeation test for whole boots showed shorter permeation times than those of the component materials, according to JIS T 8117:2005. The permeation time of toluene was more than twice that of boots C and D. The permeation time of dichloromethane was more than twice that of boots A and C and more than 3 times shorter for boot A.
Conclusions
The differences between the whole-boot tests and the material tests were thought to be related to variations in thickness, type of material, difference in adhesion, and penetration from pinwheels. This method enables the determination of the permeation of chemicals and other performance characteristics of the whole boot, which cannot be determined using testing of material specimens alone. By using this device for testing, appropriate boots that are protective against specific chemicals and can prevent chemically induced damage to the feet can be more efficiently selected.journal articl
Monte Carlo study on critical exponents of the classical Heisenberg model in ferromagnetic icosahedral quasicrystal
Get PDFQuasicrystals (QCs) lack three-dimensional periodicity of atomic arrangement but possess long-range structural order, which are distinct from periodic crystals and random systems. Here, we show how the ferromagnetic (FM) order arises in the icosahedral QC (i-QC) on the basis of the Monte Carlo simulation of the Heisenberg model on the Yb lattice of Cd5.7 Yb composed of regular icosahedrons. By finite-size scaling of the Monte Carlo data, we identified the critical exponents of the magnetization, magnetic susceptibility, and spin correlation length, =0.508 (30), =1.361 (59), and =0.792 (17), respectively. We confirmed that our data satisfy the hyperscaling relation and estimated the other critical exponents =−0.376 (51), =3.68 (23), and =0.282 (65). These results show a universality class inherent in the i-QC, which is different from those in periodic magnets and spin glasses. In the i-QC, each Yb site at vertices of the regular icosahedrons is classified into eight classes with respect to the coordination numbers of the nearest-neighbor and next-nearest-neighbor bonds. We revealed the FM-transition mechanism by showing that the difference in the local environment of each site is governed by cooperative evolution of spin correlations upon cooling, giving rise to the critical phenomena.journal articl