利用微细质点的热影响区细晶高韧性化技术的开发

为满足490—590MPa级厚钢板使用中对焊接大线能量化、高强度厚板化、高韧性化的要求．开发出新的超越了已有技术界限的热影响区细晶高韧性化技术．从而可以得到韧性良好的热影响区。该技术旨在明显抑制熔合线附近热影响区内奥氏体晶粒长大，使高温热稳定性优良的氧化物或硫化物在钢中微细分散。通过显著细化奥氏体晶粒来微细化热影响区组织。技术要点是确定工业方法，使含有适量镁或钙、尺寸为数十纳米至数百纳米的钢中氧化物或硫化物密而分散。该技术适用于建筑、造船、海洋工程结构和石油管线用厚钢板，在确保焊接钢结构安全可靠基础上，提高焊接热影响区的韧性。     

Optimization of Construction of Tire Reinforcement by Genetic Algorithm

A new tire design procedure capable of determining the optimum tire construction was developed by combining a finite element method approach with mathematical programming and a genetic algorithm (GA). Both procedures successfully generated optimized belt structures. The design variables in the mathematical programming were belt angle and belt width. Using the merits of a GA which enabled the use of discrete variables, the design variables in the GA were not only the topology of the belt and belt angle but also the belt material. Furthermore, a discrete objective function such as the number of parts could be optimized in the GA. The optimized structure obtained by the GA was verified to increase the cornering stiffness more than 15 percent as compared with the control structure in an indoor drum test.     

Organic π-type thermoelectric module supported by photolithographic mold: a working hypothesis of sticky thermoelectric materials

To examine the potential of organic thermoelectrics (TEs) for energy harvesting, we fabricated an organic TE module to achieve 250 mV in the open-circuit voltage which is sufficient to drive a commercially available booster circuit designed for energy harvesting usage. We chose the π-type module structure to maintain the temperature differences in organic TE legs, and then optimized the p- and n-type TE materials’ properties. After injecting the p- and n-type TE materials into photolithographic mold, we eventually achieved 250 mV in the open-circuit voltage by a method to form the upper electrodes. However, we faced a difficulty to reduce the contact resistance in this material system. We conclude that TE materials must be inversely designed from the viewpoints of the expected module structures and mass-production processes, especially for the purpose of energy harvesting.     

Development of self-conducting current bypass circuit for series-connected diodes in high power semiconductor light source

This paper proposes a self-conducting current bypass circuit for series-connected diodes in high power semiconductor light source. This circuit enables the main circuit current flow continuously, even if several of the diodes connected in series are open because of breakdowns. Herein, the composition, operation, and circuit design method of the proposed circuit are described. Moreover, the development of a simulation model of the fuse, which is an element of the circuit, is described. Furthermore, the simulation result of the proposed circuit using the fuse model is presented, and the method of determining the circuit constant based on the simulation result is demonstrated. Finally, by connecting a prototype circuit based on this study in parallel with series-connected diodes, we show that the main circuit current of 60 A flow continuously even when one of the diodes is open.     

Phases on the “Perovskite Line” in the La-Sr-Cu-O System

Our recent research in the La-Sr-Cu-O system has revealed the existence of two new oxygendeficient compounds. One is (La_1–x Sr _x )₄Cu₄O₁₀ (x=0.135–0.15 4-4-10 phase), which has the same structure as CaMnO_2.5 and transforms to the well-known (La_1–x Sr _x )₈Cu₈O₂₀ (x=0.135–0.30 8-8-20 phase) at higher temperature. The other is (La_1–x Sr _x )₅Cu₅O₁₃ (x=0.125–0.1666 5-5-13 phase), which is synthesized under high oxygen pressure and is isostructural to La₄BaCu₅O₁₃ (4-1-5 phase). We have also studied the strontium-rich compound (La_1–x Sr _x )₈Cu₈O₁₆₊ (x=0.7–0.8 8-8-16+ phase) and isolated the semiconductor-like 8-8-16 phase (0.0) and the metallic 8-8-18 phase (>2.0). Cations (La and Sr) in several of these compounds on the (La+Sr)Cu=11 line, which we call the perovskite line, are distributed in a disordered manner and their crystal structures can be explained by the systematic removal of oxygen atoms from an ideal perovskite structure.     

Structural properties and phase diagram of La2MO4+δ (M=Ni, Cu)

The phase diagram of La₂MO₄₊ (M=Ni, Cu) and the temperature dependence of orthorhombicity for several orthorhombic phases were investigated byin situ X-ray powder diffraction. A successive phase transition, tetragonalI4/mmm-[second-order] orthorhombicBmab-[ first-order] orthorhombicPccn, was observed in La₂NiO_4.00. The orthorhombicity of thePccn phase decreases on cooling in contrast to that of theBmab phase. The orthorhombic La₂NiO_4.15 (Fmmm) shows a weak temperature dependence of orthorhombicity and exhibits a first-order phase transition to the tetragonalI4/mmm phase on heating. As judged from the temperature dependence of orthorhombicity, superconducting La₂CuO_4.07, which results from the phase separation in the high-pressure oxygenated sample, isBmab, while La₂CuO_4.07 prepared by electrochemical oxidation at room temperature isFmmm.     

Stable impact and contact force control by UAV for inspection of floor slab of bridge

ABSTRACT

This paper describes the contact force control on an unmanned aerial vehicle (UAV) developed to inspect the floor slabs of bridges. Our UAV is equipped with a three degree-of-freedom manipulator on top of the UAV body. To control the UAV for stable contact with the slab surface, the impact force should be considered. The impact force is modeled based on Hertzian contact stress. The control strategy of the UAV is cascade control separated into attitude control and position-force control. The attitude, position and force feedback are PID control. The force feedback is integrated into the position feedback seamlessly, and the output of the force feedback is added to the desired end-point position of the manipulator. This paper focuses on contact of the UAV and the floor slab. Therefore, the UAV is modeled considering the impact force in the vertical direction. The control method in the vertical direction is described, and then the altitude control and the contact force control are assessed. The altitude of the UAV was controlled with a 0.45?[sec] delay during ascending and 1.76?[sec] during descending. The UAV could control the contact force with mean error 1.61 ± 1.08?[N] while the desired contact force was 3?[N].     

Growth Mechanism of Nanometer-Sized SiC and Oxidation Resistance of SiC-Coated Diamond Particles

Diamond particles were coated with a thin SiC layer by the reaction of SiO vapor with diamond, and the growth mechanism of SiC as well as the oxidation resistance of the SiC-coated diamond were studied. The growth process of the SiC layer can be separated into two steps. In the first step, a thin layer of SiC with a thickness of about 15 nm is formed due to the reaction between SiO vapor and diamond. In the second step, nanometer-sized SiC granules are deposited on the SiC layer by the reaction between SiO vapor and CO. The apparent activation energy for the formation of SiC layer on diamond was found to be 100 kJ/mol. This value suggests that the SiC coating process occurred mainly by vapor-phase reaction. The oxidation resistance of the SiC-coated diamond was improved depending on the thickness of the SiC layer. Oxidation of the SiC-coated diamond particles began at 950°C, which was 400°C higher than that of uncoated diamond.     

Anionic polymerization using rotating disk reactor (I)

Anionic polymerization of styrene with sodium naphthalene was carried out using the rotating disk reactor. The mode of disintegration of the polymerization mixture changed from dropwise to filamentwise and finally to filmwise within a few minutes of reaction at low speed revolution and a large amount of flow. Under the condition of high speed revolution and a small amount of flow, only dropwise disintegration was observed and a beadlike polymer was obtained having a unimodal molecular weight distribution. The polymer was found to have a bimodal distribution when the polymerization was terminated on the rotating disk. These results are explained by assuming that a highly viscous layer was formed near the disk surface.