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Patent
Paramount Energy Laboratory Ltd. and Tokyo Metropolitan College of Industrial Technology | Date: 2012-11-08

A pattern of a reaction gas flow passage in a separator plate of a fuel cell is formed by screen printing with high accuracy. The invention relates to a method of producing a separator plate for fuel cell, the method including forming a partition wall (11) having a predetermined pattern which is to be a reaction gas flow passage on a base plate (10a), wherein two or more coats of an ink composition containing a conductive material are laminated on the base plate by screen printing to form conductive ink layers (11a to 11c) having a predetermined thickness as the partition wall (11).


Nakano M.,Tokyo Metropolitan College of Industrial Technology
Transactions of the Japan Society for Aeronautical and Space Sciences | Year: 2012

A sensitivity analysis was performed using a three-dimensional code to understand the effect of doubly charged ions on the erosion of ion acceleration grids. A preliminary analysis showed that the neutral mass flow rate, estimated by assuming all the ions are singly charged, contained significant error when the doubly charged ion fraction was non-negligible. Calculations were conducted for the μ10 EM1 ion acceleration grid system with different doubly charged ion fractions. For fractions of 0.1 and 0.2, which were similar to the experimental conditions, the simulation results for the acceleration grid current and grid mass loss were in good agreement with the experimental data. Calculations showed that when the doubly charged ion fraction was reduced from 0.1 to 0, the acceleration grid current and grid mass loss changed by -14% and -18%, respectively. Further, when the fraction was increased from 0.1 to 0.2, the acceleration grid current and grid mass loss changed by +9.5% and +32%, respectively. Electron backstreaming was also found to vary with the doubly charged ion fraction: it occurred 14% slower when the fraction was decreased from 0.1 to 0 and 12% faster when the fraction was increased from 0.1 to 0.2. The structural failure of the deceleration grid was less sensitive: the deceleration grid eroded 8.3% slower when the doubly charged ion fraction was reduced from 0.1 to 0 and 8.6% faster when the fraction was increased from 0.1 to 0.2. © 2012 The Japan Society for Aeronautical and Space Sciences.


Wakaumi H.,Tokyo Metropolitan College of Industrial Technology
Proceedings of the SICE Annual Conference | Year: 2011

This paper presents a high-speed CMOS OP Amp with a dynamic switching bias circuit capable of processing video signals of over 2 MHz with decreased dissipated power. The OP Amp, capable of operating at 10 MHz dynamic switching rate, was designed and showed through simulations a dissipated power of 66 % of that in conventional continuous operation. This OP Amp was applied to a switched capacitor (SC) non-inverting amplifier with a gain of 2 and its high-speed 10 MHz dynamic switching operation, capable of processing video signals, was demonstrated. By increasing the switching duty ratio to 70 %, its power dissipation decreased to 56 % of that in normal operation. Some inaccuracy of the SC amplifier resulted mainly from the limited open gain of the OP Amp. This circuit configuration should be extremely useful in realizing low-power wide-band signal processing ICs. © 2011 SICE.


Suzuki T.,Tokyo Metropolitan College of Industrial Technology
Applied Physics Letters | Year: 2015

Group III-V compounds are very important as the materials of semiconductor devices. Stable structures of the monolayers of group III-V binary compounds have been discovered by using first-principles calculations. The primitive unit cell of the discovered structures is a rectangle, which includes four group-III atoms and four group-V atoms. A group-III atom and its three nearest-neighbor group-V atoms are placed on the same plane; however, these connections are not the sp2 hybridization. The bond angles around the group-V atoms are less than the bond angle of sp3 hybridization. The discovered structure of GaP is an indirect transition semiconductor, while the discovered structures of GaAs, InP, and InAs are direct transition semiconductors. Therefore, the discovered structures of these compounds have the potential of the materials for semiconductor devices, for example, water splitting photocatalysts. The discovered structures may become the most stable structures of monolayers which consist of other materials. © 2015 AIP Publishing LLC.


Cao M.,Tokyo Metropolitan College of Industrial Technology
2010 International Power Electronics Conference - ECCE Asia -, IPEC 2010 | Year: 2010

An electrical losses (copper and iron losses) minimization control of interior permanent magnet synchronous motors is proposed in this paper. Until now a Look-up Table based maximum torque per armature current control strategy was proposed by authors. That is a control to minimize copper losses. Meanwhile, the efficiency deteriorates as a result that the iron losses increase sharply in high speed area. In this paper, a model considering iron losses is discussed and the relationship between the electrical losses and d-q axes current, motor torque, motor speed is clarified at first. Next, measurement experiments are made to prove that there is an optimal armature current phase which minimize the electrical losses for given motor speed and load torque. Then, an online loss minimization algorithm with steepest descent method (golden section method) is proposed. The electrical losses in i d =0 control and loss minimization control are compared with experiment results. The effectiveness of the proposed control is verified by experiments. © 2010 IEEE.


Wakaumi H.,Tokyo Metropolitan College of Industrial Technology
Procedia Engineering | Year: 2010

A fixed-period delay method is proposed to increase the detection range and detection stability of a ternary barcode detection system. The system combines an envelope differential detection technique containing nonlinear filtering and a fixed-period delay to detect the barcode over a longer range and at higher scanning speeds while being simple and capable of handling a large amount of information. The system was demonstrated with its miniaturized circuit and it was established that the detection range of the system for a minimum bar width W = 0.25 mm was 1.8 times that of the conventional count-latch envelope differential technique because of the stable delay achieved by a shift register and the noise suppression by a nonlinear filter. In addition, the system operated at a maximum scanning speed of 8.3 times that of conventional charge-coupled device (CCD) cameras under the practical detection range for W = 0.3 mm. This system is expected to enable the real-time identification of goods on production lines and in automated warehouses.


Wakaumi H.,Tokyo Metropolitan College of Industrial Technology
Engineering Letters | Year: 2013

A high-speed three-stage CMOS OP Amp with a dynamic switching bias circuit, capable of processing video signals of over 2 MHz, is presented to provide slight nonlinearity through the achievement of higher gain while maintaining high-speed switching operation and low power dissipation. The designed OP Amp, capable of operating at 10 MHz dynamic switching rate, and through simulations showed a dissipated power of 60 % of that in conventional continuous operation. A switched capacitor (SC) non-inverting amplifier with a gain of 2 employing this OP Amp and its high-speed 10 MHz dynamic switching operation, capable of processing video signals, is demonstrated. Its power dissipation decreased to 62 % of that in normal operation when the switching duty ratio was increased to 70 %. The output voltage inaccuracy for a SC amplifier with a gain of less than 2 decreased to below 1 %, one sixth of that using a conventional two-stage OP Amp with the dynamic switching bias circuit, mainly caused by the static nonlinearity of the OP Amp. This circuit configuration will be extremely useful in realizing low-power wide-band signal processing ICs.


Nakano M.,Tokyo Metropolitan College of Industrial Technology
Vacuum | Year: 2013

Ion engines offer substantial weight savings but produce very little thrust. To meet mission requirements they must therefore be operational for extensive periods of time. Until now, all ion engines used in space missions have required expensive and time-consuming ground-based life qualification tests prior to flight. These tests can be shortened using the numerical simulation code "JIEDI" (JAXA Ion Engine Development Initiatives), which is now reaching the level of a practical engineering application. However, doubly charged ions are not fully modeled in JIEDI code. In the present study, the effect of doubly charged ions has been investigated to improve the life prediction accuracy of ion acceleration grid simulations. Findings show that the grid erosion increases with an increasing doubly charged ion fraction under the same propellant flow rate and the same beam current condition, which suggests that the doubly charged ion fraction is a crucial factor in life prediction accuracy. © 2012 Elsevier Ltd. All rights reserved.


Noge Y.,Tokyo Metropolitan College of Industrial Technology
9th International Conference on Power Electronics - ECCE Asia: "Green World with Power Electronics", ICPE 2015-ECCE Asia | Year: 2015

This paper proposes a linear AC LED driver for LED lighting applications. The proposed circuit is small in size because the circuit structure consists of only semiconductors and resistors without any reactors and electrolytic capacitors. The current bypass circuit which is connected in parallel to the LED string consists of single MOSFET, single zener diode and two resistors. The MOSFET is operated in an active state by a self-bias circuit. Thus, an external controller and high voltage gate drivers are not required. The proposed circuit is experimentally validated by using a 7 W prototype. From the experimental results, the THD of input current is 2.1% and the power factor is 0.999. In addition, the simulation loss analysis demonstrates an efficiency of 87% for a 7 W prototype. © 2015 Korean Institute of Power Electronics.


Wakaumi H.,Tokyo Metropolitan College of Industrial Technology
International Conference on Control, Automation and Systems | Year: 2012

This paper presents a high-speed CMOS OP Amp with a dynamic switching bias circuit capable of processing video signals of over 2 MHz with slight nonlinearity and low dissipated power. The OP Amp, capable of operating at 10 MHz dynamic switching rate, was designed and showed through simulations a dissipated power of 60 % of that in conventional continuous operation. A switched capacitor (SC) non-inverting amplifier with a gain of 2 employing this OP Amp and its high-speed 10 MHz dynamic switching operation, capable of processing video signals, was demonstrated. By increasing the switching duty ratio to 70 %, its power dissipation decreased to 62 % of that in normal operation. The output voltage inaccuracy for a SC amplifier with a gain of below 2 was below 1 % and mainly caused by the static nonlinearity of the OP Amp. This circuit configuration should be very useful in realizing low-power wide-band signal processing ICs. © 2012 ICROS.

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