Showing papers in "Ieej Transactions on Sensors and Micromachines in 2003"
29 citations
TL;DR: The MEMS rotary engine power system project at the Berkeley Sensor & Actuator Center of the University of California at Berkeley as mentioned in this paper was the first attempt to use MEMS technology for power generation at the microscale.
Abstract: This work presents a project overview and recent research results for the MEMS Rotary Engine Power System project at the Berkeley Sensor & Actuator Center of the University of California at Berkeley. The research motivation for the project is the high specific energy density of hydrocarbon fuels. When compared with the energy density of batteries, hydrocarbon fuels may have as much as 20x more energy. However, the technical challenge is the conversion of hydrocarbon fuel to electricity in an efficient and clean micro engine. A 12.9 mm diameter Wankel engine will be shown that has already generated 4 Watts of power at 9300rpm. In addition, the 1mm and 2.4 mm Wankel engines that BSAC is developing for power generation at the microscale will be discussed. The project goal is to develop electrical power output of 90milliwatts from the 2.4 mm engine. Prototype engine components have already been fabricated and these will be described. The integrated generator design concept utilizes a nickel-iron alloy electroplated in the engine rotor poles, so that the engine rotor also serves as the generator rotor.
29 citations
TL;DR: In this article, a pneumatically-actuated, normally-closed microvalve regulates capillary-driven flow for mixing liquids, and a simple method for controlling the mixing ratio is also demonstrated.
Abstract: In this paper, a novel microfluidic device for mixing liquids is described. Main feature of this device is that the liquids are passively pumped through microchannels only by capillary action, and therefore no external power is required for the pumping. This feature brings extremely simple hardware setup and easy operation. In this device, a pneumatically-actuated, normally-closed microvalve regulates capillary-driven flow. The device has been fabricated with polydimethylsiloxane (PDMS) elastomer, and tested using fluorescent dye and fluorescent particle solutions. A simple method for controlling the mixing ratio is also demonstrated.
23 citations
TL;DR: In this paper, a MEMS-based fuel reformer for supplying hydrogen to micro-fuel cells for portable applications is reported, where a combustor and a reforming chamber are fabricated at either side of a suspended membrane structure.
Abstract: We report a MEMS-based fuel reformer for supplying hydrogen to micro-fuel cells for portable applications. A combustor and a reforming chamber are fabricated at either side of a suspended membrane structure. This design is used to improve the overall thermal efficiency, which is a critical issue to realize a micro-fuel reformer. The suspended membrane structure design provided good thermal isolation. The micro-heaters consumed 0.97W to maintain the reaction zone of the MEMS-based fuel reformer at 200°C, but further power saving is necessary by improving design and fabrication. The conversion rate of methanol to hydrogen was about 19% at 180°C by using evaporated copper as a reforming catalyst. The catalytic combustion of hydrogen started without any assistance of micro-heaters. By feeding the fuel mixture of an equivalence ratio of 0.35, the temperature of the suspended membrane structure was maintained stable at 100°C with a combustion efficiency of 30%. In future works, we will test a micro-fuel reformer by using a micro-combustor to supply heat.
13 citations
TL;DR: In this paper, a sound source localization mechanism with a gimbal diaphragm was proposed, which realized a simple and optimal transduction mechanism for a very small pressure gradient caused by the sound field.
Abstract: The parasitoid fly Ormia Ochracea shows a remarkable ability to detect the direction of an incident sound even though its ears are in very close to each other, where the interaural differences in intensity and time are extremely small.In this paper, with mimicking the unique auditory organ of the fly, we propose a sound source localization mechanisms with a gimbal diaphragm which realizes a simple and optimal transduction mechanism for a very small pressure gradient caused by the sound field.We made a model sensor using a thin metal plate and confirmed that it localizes the direction of the sound source by experiments.
12 citations
Journal Article•
TL;DR: In this article, a novel anti-slip readhesion control without speed sensor is proposed, where small wheel slips can be easily detected and the performance is expected to be as high as that of the control with speed sensor.
Abstract: Since the advent of railway vehicles with three-phase drive in the 1970s, power semiconductors used in electric railway vehicles have been changed from thyristors to GTO thyristors and IGBTs. As for traction motor control, vector control has come into wide use in place of slip frequency control and vector control without speed sensor is at a trial stage for commercial trains. Anti-slip and readhesion control of railway vehicles has greatly progressed by utilizing wheel axle speed information. Locomotives and electric multiple units with speed-sensor-less vector control in the future should have at least the same adhesion performance as that of the alternatives with speed sensor. In this paper, a novel anti-slip readhesion control without speed sensor is proposed. By this method small wheel slips can be easily detected. Its performance is expected to be as high as that of the control with speed sensor. This paper enumerates the characteristics of wheel slip phenomenon and anti-slip control for railway vehicles, explains the running test results that show basics of anti-slip readhesion control with speed sensors, describes an outline of the novel anti-slip readhesion control without speed sensor, and verifies the basic functions by simulation.
10 citations
TL;DR: In this article, a spectrophotometric flow-injection analysis (FIA) system was used for the determination of urea in rice wines by using an acid urease column as a recognition element.
Abstract: Determination of urea in rice wines was performed by using a spectrophotometric flow-injection analysis (FIA) system introducing an acid urease column as a recognition element. An acid urease, having specific properties of showing catalytic activity in low pH range and tolerance to ethanol in comparison to those of a urease from jack-beans, was covalently immobilized onto porous glass beads and then, packed into a small polymer column. This flow-type of the biosensing system was assembled with a sample injection valve, the immobilized enzyme column, a gas-diffusion unit, and a flow-through quartz cell attached to a UV/VIS detector. Standard urea solutions were measured through monitoring variations in absorbance resulting from pH shift due to ammonia molecules enzymatically generated. A wide, linear relationship was obtained between the concentration of urea (7.8 µM - 1.0 mM) and the change in absorbance. Followed by several investigations for application of this FIA system for measurement of urea in commercially available rice wines, the real samples were injected into the FIA system and urea in the samples were determined. These results were compared with those obtained with use of an F-kit method which was widely used for determination of urea. Comparative studies exhibited that this FIA system might be a powerful tool for urea determination in alcoholic beverages.
10 citations
10 citations
TL;DR: In this paper, a dicing method for MEMS devices without dameges during the dicing process is presented based on bonding and detachment of a glass cap plate by using thermoplastic adhesive.
Abstract: This paper presents a dicing method for MEMS devices without dameges during the dicing process. The method is based on bonding and detachment of a glass cap plate by using thermoplastic adhesive. Sand blast technique was used for the fabrication of glass cap plate which has concavities in the depth of 100µm. The thermoplastic adhesive was screen printed on the glass plate. The plate was thermocompression-bonded to silicon wafer at 210°C and diced to individual chips without damages from water or dicing dusts. The chip was mounted in the package while the glass cap was removed at 330°C.
9 citations
TL;DR: The cross-linked GDH immobilized electrode showed good storage stability and the flow injection analysis (FIA) glucose sensing system was also constructed by immobilizing the cross- linked GDH and ferrocene as a mediator in the carbon paste matrix.
Abstract: A thermostable mediator-type enzyme glucose sensor was constructed. The electrode was fabricated using chemically cross-linked thermostable co-factor binding glucose dehydrogenase (GDH) from thermophilic bacteria in carbon paste matrix. The electrode responded directly proportional to D-glucose concentration from 0.01 mM to 3 mM in stirred buffer containing 1 mM 1-methoxyphenazinemethosulfate as a mediator with the steady-state mode. The storage stability was examined by incubating the enzyme electrode at 50oC during the measurement. The cross-linked GDH immobilized electrode showed good storage stability. Ninety percent of its initial response was retained after incubation in buffer solution for 9 days at 50oC. The flow injection analysis (FIA) glucose sensing system was also constructed by immobilizing the cross-linked GDH and ferrocene as a mediator in the carbon paste matrix. The FIA system was able to measure 600 samples for 100 h.
9 citations
TL;DR: In this paper, a simple new configuration for a switched capacitor type C-V converter based on a charge balance principle for a differential capacitance sensor and its simulation results was devised and realized using only one operational amplifier, nine CMOS switches and an oscillation circuit.
Abstract: This paper presents a simple new configuration for a switched capacitor type C-V converter based on a charge balance principle for a differential capacitance sensor and its simulation results. The new converter was devised and realized using only one operational amplifier, nine CMOS switches and an oscillation circuit. It was shown that the offset output due to the input offset voltage of an operational amplifier can be ideally reduced to zero with an appropriate additional switch configuration. By using a P-Spice circuit simulator, the offset cancellation scheme and proper transient response were confirmed for possible parasitic capacitances concerned in a typical differential capacitance sensor. In addition, a P-Spice system simulation based on analog behavioral models enabled us to reliably estimate the operation of an electro-mechanical system with the C-V converter statically and dynamically, where the electrostatic force acting on a movable electrode was taken into account.
TL;DR: Experimental results confirmed the model achieves real time simulation of the surgical palpation and calculates soft tissue deformation according to the affection of inner pressure and the operation of a surgeon.
TL;DR: In this paper, the authors used a mass spectrum pattern to determine the recipe of a target odor with sufficient accuracy to realize an odor recorder for recording and reproducing it using a mass spectrometer.
Abstract: It is necessary to determine the recipe of a target odor with sufficient accuracy to realize an odor recorder for recording and reproducing it. We studied the recipe measurement method of a target odor using a mass spectrometry. It was confirmed that the linear superposition was valid when the binary mixture of the apple-flavor components such as isobutyric acid and ethyl valerate was measured. The superposition of a mass spectrum pattern may enable the recipe determination of a multi-component odor easily. In this research, we succeeded in the recipe determinations of orange flavor made up of 14 component odors when its typical recipe, the equalized, the citral-enhanced and the citronellol-enhanced ones were measured.
TL;DR: In this paper, a suppression method of generated distortion on the beam structures due to thermal stress is investigated for reduction of remainder thermal drift in three-axis accelerometer for high temperatures.
Abstract: In this paper, a suppression method of generated distortion on the beam structures due to thermal stress is investigated for reduction of remainder thermal drift in three-axis accelerometer for high temperatures. An arrangement of piezoresistors for acceleration detection is presented to further reduction of thermal drift. Thermal drift analysis and design of advanced three-axis accelerometer for high temperatures without temperature dependence has been carried out with the finite element method (FEM) program, ANSYS. Experimental results agreed well with these theoretical results. Design considerations that enable the three-axis accelerometer to have stable sensitivity and offset are described with the simulated results.
Journal Article•
TL;DR: In this paper, the tractive coefficient between the wheels and the rails has a peak at a certain slip velocity and the adhesive phenomenon has not been clearly examined or analyzed, but the authors have developed new tractive test equipment.
Abstract: The acceleration and deceleration rate of a train depends on the tractive force. When the wheels of a train slip on the rails, the torque is decreased to avoid continuous slipping. This is done because the tractive coefficient between the wheels and the rails has a peak at a certain slip velocity. But this adhesive phenomenon has not been clearly examined or analyzed. For this purpose, we have developed new tractive test equipment. In this paper, we measure the tractive force with this equipment, and clarify the adhesive phenomenon. Then we propose new tractive force control and verify the effectiveness of this control scheme. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(2): 49–59, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10376
TL;DR: The piezoelectric effect (PE) effect as mentioned in this paper has been shown to be a powerful mechanism for inducing the effect of the piezelectric effects on the environment.
Abstract: ある種の結晶では,機械的な歪みをかけると結晶内のカ チオンとアニオンの相対的な位置関係が変化し,結果とし て両者の重心は一致しなくなり分極が生じる。この現象は 圧電効果(piezoelectric effect)と呼ばれている。逆に結晶 の上下に電極を取り付けて電圧を加えると,カチオンは負 電極方向へアニオンは正電極方向へと移動し,結晶は歪み を生じることになる(逆圧電効果)(図 1)。これらの現象は 1880年にフランスの物理学者J. CurieとP. Curie兄弟によ って発見された(3)。この発見の重要性は,機械的現象と電気 的現象がイオン結晶を介して結びつけられた点にある。この ような圧電効果は,水晶,ロッシェル塩(NaKC4H4O6•4H2O), 電気石など種々の結晶に見いだされているが,その中でも 特に水晶(石英,quartz ; SiO2)は,圧電特性,化学的性 質,熱的安定性に優れていることが知られている。 このような逆圧電効果を利用して,水晶板の両面に電極 を取り付けたものに電圧をかけて歪みを生じさせ,その後, 印加電圧を解除すると,水晶板はずり運動を生じてから元
IBM1
TL;DR: In this article, a new micromachined nano tweezers integrated with thermal expansion micro actuators was developed, where the gap between the two probe tips can be controlled by the integrated Si thermal expansion acutuators.
Abstract: We have developed a new micromachined nano tweezers integrated with thermal expansion micro actuators.The device structure was de.ned by etching of a 30µm-thick silicon-on-insulator wafer (SOI) using an inductively coupled plasma reactive ion etching apparatus (ICP-RIE). To obtain the tip radius of less than 10nm and to align two probe tips, new process sequence was designed by combining wet anisotropical etching of silicon with the ICP-RIE. The gap between the two probe tips can be controlled by the integrated Si thermal expansion acutuators which are 500µm in length, 50µm in width, and 30µm in thickness. Since the displacement of the probe tip is mechanically magni.ed by 5 times as the thermal expansion displacement, 2µm displacement toward the opposing probe tip was observed when 0.4 W was applied to the thermal expansion actuator, which quantitatively agreed with theoretical prediction.
TL;DR: A multi-functional tactile sensor with a simple structure to imitate the human hand is proposed, characterized by the small sensing area and the moving measurement method.
Abstract: The aim of this study is to propose a multi-functional tactile sensor with a simple structure to imitate the human hand. It is characterized by the small sensing area and the moving measurement method. A step-by-step method is used to realize the multi-functional sensing and in each step, different material characteristics are sensed. By analyzing the output of the sensor, three material properties, i.e., metal or non-metal, hard or soft, and curved or plane surface, and the environment temperature can be obtained. A detailed analysis of the step-by-step method to the sensor is made.
TL;DR: In this article, the fabrication technology and device characteristics of junction field effect transistor (JFET) which can be integrated in CMOS sensor interface circuits are presented, and the JFET is applicable to CMOS (operational) amplifiers to realize a very low-noise front-end amplifier in sensor interfaces.
Abstract: In this paper, fabrication technology and device characteristics of junction field effect transistor (JFET) which can be integrated in CMOS sensor interface circuits are presented. The JFET is applicable to CMOS (operational) amplifiers to realize a very low-noise front-end amplifier in sensor interface circuits. It is formed with isolated p-well area in CMOS device. Extra processes to a standard CMOS technology are one photolithography process and two ion-implantation processes. N-type channel in JFET is formed by deep ion-implantation of phosphorous with energy of 150 keV to connect n+ source and drain regions. After that, p-type top gate region is formed by shallow ion-implantation of borron with energy of 30 keV. Fabricated JFET devices showed enough transconductance and low drain conductance, which are suitable to use them in analog amplifiers. Noise power-spectrum of the fabricated JFET was evaluated, and compared with n-MOSFET and p-MOSFET. As a result, noise-spectrum of JFET below 1 kHz was much lower than that of CMOS devices. Since many physical sensors have their signal bandwidth in low frequency band, this JFET device can be utilized in CMOS-based front-end amplifiers as the key device of low-noise sensor interface circuits.
TL;DR: X3D as discussed by the authors is a moving mask deep X-ray lithography simulation system for 3Dimensional Fabrication that is tailored to simulate the fabrication process of 3D microstructures using the M2DXL technique.
Abstract: We have developed an X-ray lithography simulation system X3D (Moving Mask Deep X-ray Lithography Simulation System for 3-Dimensional Fabrication) for the first time, that is tailored to simulate the fabrication process of 3-dimensional microstructures using the M2DXL (Moving Mask Deep X-ray Lithography) technique. The newly developed X3D can simulate the progress of developed PMMA surface with developing time using chemical dissolution rate data as a function of dose energy. The simulation system consists of three modules: mask generation, exposure, and development. The exposure module calculates a dose energy distribution over a PMMA using a mask pattern and its movement pattern, and then converts this dose energy to a dissolution rate of PMMA. The development module adopted a \"Fast Marching Method\" to calculate the resultant 3D shape of the PMMA. In this paper, a new experimental method to determine dissolution rate as a function of dose energy that dominates the simulation accuracy was proposed. An experimental procedure of the new experimental method, the determined dissolution rate, and verification of the measured results are presented.
TL;DR: In this paper, a reciprocating engine was designed for a micro power generator with an elastic spring system, which was used for a portable micro-power generator with high energy density, and the theoretical output was found to be 41 mW under the conditions that compression ratio is 5, the maximum combustion temperature is 850 K and resonance frequency of the spring system is 582 Hz.
Abstract: A reciprocating engine was designed for a micro power generator. It is expected to be used for a portable micro power generator with high energy density. The proposed reciprocating engine has the spring system, which is composed of opposite-pistons supported by an elastic spring. Combination of resonance of the spring system by the combustion pressure and an induction coil generates electricity due to generated voltage. Working cycle analysis, structural analysis, vibration analysis, and generated voltage calculations were carried out. Adopting H2 gas as a fuel and Si as a structural material, the theoretical output was found to be 41 mW under the conditions that compression ratio is 5, the maximum combustion temperature is 850 K and resonance frequency of the spring system is 582 Hz.