Lithographie Galvanoformung Abformung (LIGA) is a promising approach for fabrication of high aspect ratio 3D microactuator for dual-stage slider in hard disk drive. However, this approach involves practically challenging X-ray lithography and structural transfer processes. In this work, electrostatic MEMS actuator is developed based on a LIGA approach with cost-effective X-ray lithography and dry-film-transfer-to-PCB process. X-ray lithography is performed with X-ray mask based on lift-off sputtered Pb film on mylar substrate and photoresist application using casting-polishing method. High quality and high aspect ratio SU8 microstructures with inverted microactuator pattern have been achieved with the interdigit spacing of ~5 μm, vertical sidewall and a high aspect ratio of 29 by X-ray lithography using the low-cost Pb based X-ray mask. A new dry-film-transfer-to-PCB is employed by using low-cost dry film photoresist to transfer electroplated nickel from surface-treated chromium-coated glass substrate to printed circuit board (PCB) substrate. The dry film is subsequently released everywhere except anchor contacts of the electrostatic actuator structure. The fabricated actuator exhibits good actuation performance with high displacement at moderate operating voltage and suitably high resonance frequency. Therefore, the proposed fabrication process is a promising alternative to realize low-cost MEMS microactuator for industrial applications. 相似文献
Carbon nanotube (CNT) is a useful material for gas-sensing applications because of its high surface to volume ratio structure.
In this work, multi-wall CNTs are incorporated into tin oxide thin film by means of powder mixing and electron beam evaporation
and the enhancement of gas-sensing properties is presented. The CNTs were combined with SnO2powder with varying concentration in the range of 0.25–5% by weight and electron beam evaporated onto glass substrates. From
AFM and TEM characterization, CNT inclusion in SnO2thin film results in the production of circular cone protrusions of CNT clusters or single tube coated with SnO2layer. Experimental results indicate that the sensitivity to ethanol of SnO2thin film increases by the factors of 3 to 7, and the response time and recovery time were reduced by the factors of 2 or
more with CNT inclusion. However, if the CNT concentration is too high, the sensitivity is decreased. Moreover, the CNT doped
film can operate with good sensitivity and stability at a relatively low temperature of 250–300∘C. The improved gas-sensing properties should be attributed to the increasing of surface adsorption area of metal oxide produced
by CNT protrusion. 相似文献
This paper presents a business model guideline of electricity utility systems based on blockchain technology in Thailand: a case study of consumers, prosumers and SMEs. Because the resource management of electricity utility systems in Thailand presently are based on enhanced single buyer or a centralized system. However, a free-trade energy market is likely to open or occur in the near future. Thus, a preparation of changing or adapting such a free-trade energy market using disruptive technology is an important point to study the aforementioned disruptive technology (i.e. blockchain technology). The future business of the free-trade energy market is related to the policy of the government (Thailand 4.0). It will support technology development and innovation to encourage the potential and readiness and to compete for foreign countries. In this scoping study, the business model guideline of electricity trading with peer to peer (P2P) is proposed to utilize the case study of consumers and prosumers/SMEs in Thailand based on a decentralized system. The P2P trading is directly the buying and selling of electricity between both consumers and prosumers. It is not a passed intermediary; otherwise, an intermediate process can be cut by this trading in order to save and reduce electricity costs. Preliminary expected impacts of cost structure analysis are summarized in terms of comparisons between the existing electricity trading and the blockchain technology. The results of such preliminary expected impacts show that costs to consumers, prosumers and SMEs obtained from the use of blockchain technology are possibly lower than those of EGAT, PEA, and MEA in the future. In addition, the business model guideline is completely discussed by theory in disruptive innovation.
Unloaded and 0.25–1.0 wt% Pt-loaded WO3 nanoparticles were synthesized by hydrothermal method using sodium tungstate dihydrate and sodium chloride as precursors in an acidic condition and impregnated using platinum acetylacetonate. Pt-loaded WO3 films on an Al2O3 substrate with interdigitated Au electrodes were prepared by spin-coating technique. The response of WO3 sensors with different Pt-loading concentrations was tested towards 0.01–1.0 vol% of H2 in air as a function of operating temperature (200–350 °C). The 1.0 wt% Pt-loaded WO3 sensing film showed the highest response of ∼2.16 × 104 to 1.0 vol% H2 at 250 °C. Therefore, an operating temperature of 250 °C was optimal for H2 detection. The responses of 1.0 wt% Pt-loaded WO3 sensing film to other flammable gases, including C2H5OH, C2H4 and CO, were considerably less, demonstrating Pt-loaded WO3 sensing film to be highly selective to H2. 相似文献
Polyaniline is one of the most promising conducting polymers for gas sensing applications due to its relatively high stability and n or p type doping capability. However, the conventionally doped polyaniline still exhibits relatively high resistivity, which causes difficulty in gas sensing measurement. In this work, the effect of carbon nanotube (CNT) dispersion on CO gas sensing characteristics of polyaniline gas sensor is studied. The carbon nanotube was synthesized by Chemical Vapor Deposition (CVD) using acetylene and argon gases at 600 degrees C. The Maleic acid doped Emeradine based polyaniline was synthesized by chemical polymerization of aniline. CNT was then added and dispersed in the solution by ultrasonication and deposited on to interdigitated AI electrode by solvent casting. The sensors were tested for CO sensing at room temperature with CO concentrations in the range of 100-1000 ppm. It was found that the gas sensing characteristics of polyaniline based gas sensor were considerably improved with the inclusion of CNT in polyaniline. The sensitivity was increased and response/recovery times were reduced by more than the factor of 2. The results, therefore, suggest that the inclusion of CNT in MA-doped polyaniline is a promising method for achieving a conductive polymer gas sensor with good sensitivity, fast response, low-concentration detection and room-operating-temperature capability. 相似文献
The purpose of this paper was to perform studies in order to obtain a better understanding of corrosion in an aqueous amine-CO2 environment. A mechanistic corrosion model, built as a fortran-90 program, is established to identify the oxidizing agents responsible for corrosion reactions. The model incorporates the rigorous electrolyte nonrandom two-liquid (NRTL) equilibrium model and mixed potential theory in order to simulate the concentrations of chemical species and polarization behavior taking place at a metal-solution interface. The simulation results, based on monoethanolamine (MEA) system, indicates that bicarbonate ion (HCO3−) and water (H2O) are the primary oxidizing agents and hydrogen ion (H+) or hydronium ion (H3O+) plays an insignificant role in the reduction reaction. 相似文献
This paper presents the results of an investigation of the thermal mechanism between lasers and surface-micromachined micromirrors. Finite element models using ABAQUS are established and used to study the temperature distribution on the surface of micromirrors under high-power laser illumination. It is shown that heat conduction through the gas gap between the mirror surface and the substrate is the dominant thermal dissipation mechanism for high surrounding gas pressure, while heat conduction through the flexures is dominant for low surrounding gas pressure. Based on the simulation results, two novel methods are proposed in order to tolerate more power input under low surrounding gas pressure. The results of optical power testing validate these models, and indicate that these two approaches are efficient in improving micromirror performance for high-energy applications. 相似文献
The genotoxic effects of air pollutant exposures have been studied in people living and working in Map Ta Phut, Rayong province, Thailand, a site where is located the Map Ta Phut Industrial Estate (MIE) one of the largest steel, refinery and petrochemical complex in the South-Eastern Asia. This was done by the conduction of a transversal study aimed to compare the prevalence of bulky DNA adducts in groups of subjects experiencing various degree of air pollution. DNA adduct analysis was performed in the leukocytes of 201 volunteers by the (32)P-postlabelling assay: 79 were workers in the MIE complex, including 24 refinery workers, 40 steel workers and 15 tinplate workers, 72 were people residing downwind in the MIE area and 50 were residents in a control district of the same Rayong province but without industrial exposures. The groups of workers were analyzed separately to evaluate if DNA adduct formation differs by the type of industry. The levels of bulky DNA adducts were 1.17+/-0.17 (SE) adducts/10(8) nucleotides in refinery workers, 1.19+/-0.19 (SE) in steel workers, 0.87+/-0.17 (SE) in tinplate workers, 0.85+/-0.07 (SE) in MIE residents and 0.53+/-0.05 (SE) in district controls. No effects of smoking habits on DNA adducts was found. The multivariate regression analysis shows that the levels of DNA adducts were significantly increased among the individuals living near the MIE industrial complex in respect to those resident in a control district (p<0.05). In the groups of occupationally exposed workers, the highest levels of DNA adducts were found among the workers experiencing an occupational exposure to polycyclic aromatic hydrocarbons, e.g. the steel factory and refinery workers. When we have evaluated if the levels of DNA adducts of the PAH exposed workers were different from those of the MIE residents, a statistical significantly difference was found (p<0.05). Our present study indicates that people living near point sources of industrial air pollution can experiment an excess of DNA adduct formation. The emissions from the MIE complex are the main source of air pollution in this area and can be the cause of such increment in the levels of DNA damage. 相似文献