Widespread commercialization of fuel cells has been hindered by economic problems associated with the extensive use of platinum. In order to overcome such difficulties, researchers have so far developed anion-exchange membrane fuel cells (AEMFCs), which do not need expensive platinum catalysts in the electrodes. Our recent focus has been the preparation of new hydroxide (OH)-conducting membranes for applications to "hydrazine-fueled" AEMFCs by the γ-ray pre-irradiation grafting method. Generally, carbon dioxide (CO_2) is dissolved in the AEM, thereby resulting in the transformation from the OH to bicarbonate (HCO_3) ions. We investigated here the effect of CO_2 in the air on the exchange between OH and HCO_3 ions in the AEM.

关键词：燃料电池；电解质材料；化学反应

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Federal Motor Vehicle Safety Standards (FMVSS) for fuel system integrity set limits for fuel spillage during and after crashes to reduce the occurrence of deaths and injuries from fire. FMVSS 301 and 303 respectively specify post-crash limits for liquid fuels and compressed natural gas (CNG). These limits have been used as a benchmark for setting leakage limits for hydrogen, based on energy equivalence, in industry standards and proposed or enacted international regulations. However the properties of hydrogen with regard to leak behavior and combustion are very different from those of liquid fuels or CNG. Gasoline will pool and dissipate slowly. CNG and hydrogen will rise and dissipate more rapidly. Hydrogen has a much wider range of flammability in air than most fuels, including CNG: 4% to 75% for hydrogen versus 5% to 15% for CNG. Therefore, a research program was developed and executed to assess the safety of the proposed allowable leak rate for hydrogen, through leak and ignition experiments in and around vehicles and vehicle compartment simulators.

关键词：代用燃料；燃烧；死亡；消防安全；可燃性

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The aim of the project has been the analysis and development of a spinodal decomposition technology to enhance the heat transfer efficiency in microdevices. Poesio et al. (2007) had shown that the cooling (down to a given temperature) of a closed cell filled with a liquid-liquid mixture undergoing spinodal decomposition can be achieved ten-times faster compared to the case of a cell filled with a single-phase fluid. This effect can be explained as the result of (spinodal-decomposition induced) convective motion: the free energy released during spinodal decomposition acts as a driving force for the phase separation, leading to the spontaneous formation of single-phase domains which then proceed to grow and coalesce; this convective motion enhances the transport of internal energy and results in an appreciable heat transfer enhancement. Based on the proof-of-concept fundamental experiments in Poesio et al. (2006), Poesio et al. (2007), Poesio et al. (2009), and Farise et al. (2012), this technology was awaiting use in a configuration more relevant from the applications point of view, such as in a flowing system. The ultimate goal has been the design of a proof-of-concept micro/mini heat exchanger based on liquid-liquid spinodal decomposition. The project lasted for three years with the first year sponsored by the Asian Office of Aerospace Research and Development, AOARD (Grant FA2386-10-1-4146). Continued with the European office, EOARD (Grant FA8655-11-1-3068), and completed in 2013. The work has accomplished two main objectives: (1) demonstrated and analyzed heat transfer in small-scale heat exchangers; and (2) conducted numerical modeling as a precursor to a design tool. Since the currently available modeling tools require years of computational time to complete the simulation of a practical- sized device, this effort only started developing a novel theoretical modeling approach that eventually will lead to the design of efficient heat exchangers.

关键词：调幅分解；国外；换热器；传热

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The use of solar energy for mobile field operations, high altitude long endurance airships, light airship vehicles and its deployment on large scales all require its storage. Most current methods of solar storage are characterized by low energy densities; these methods therefore present formidable challenges for the implementation of solar energy in the field, on airship vehicles and on the large scale since significant weight accompanies energy storage. Conversely, fuels have energy densities that are 100 to 1000 greater than most conventional storage media, including batteries. Accordingly, fuels provide an attractive option for lightweight, mobile and large scale energy storage. An especially enticing fuel forming reaction is water splitting since hydrogen is the highest energy density chemical fuel. The use of solar light to split water to produce hydrogen and oxygen is the focus of this proposal. This AFOSR program has sought to discover new water-splitting catalysts that are inexpensive, efficient, highly manufacturable and operate under benign conditions so that discovery from this program may be implemented with simple engineering.

关键词：燃料电池；能量密度；能量存储

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A system for non-venting thermal control for spacesuits was built by integrating two previously developed technologies, namely NASA's Spacesuit Water Membrane Evaporator (SWME), and Creare's flexible version of the Lithium Chloride Absorber Radiator (LCAR). This SEAR system was tested in relevant thermal vacuum conditions. These tests show that a 1 sq m radiator having about three times as much absorption media as in the test article would be required to support a 7 hour spacewalk. The serial flow arrangement of the LCAR of the flexible version proved to be inefficient for venting non-condensable gas (NCG). A different LCAR packaging arrangement was conceived wherein the Portable Life Support System (PLSS) housing would be made with a high-strength carbon fiber composite honeycomb, the cells of which would be filled with the chemical absorption media. This new packaging reduce the mass and volume impact of the SEAR on the Portable Life Support System (PLSS) compared to the flexible design. A 0.2 sq m panel with flight-like honeycomb geometry is being constructed and will be tested in thermal and thermal vacuum conditions. Design analyses forecast improved system performance and improved NCG control. A flight-like regeneration system also is also being built and tested. Design analyses for the structurally integrated prototype as well as the earlier test data show that SEAR is not only practical for spacesuits but also has useful applications in spacecraft thermal control.

关键词：蒸发器；便携式生命保障系统；航天服

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A low voltage,low power up-conversion mixer is presented here for 2.4GHz wireless sensor networks (WSN).It was based on a double-balanced Gilbert cell type.The current-reuse technique was used to reduce the power consumption and negative-resistance compensation technique was used to improve the conversion gain.The mixer was designed in 0.18μm RF CMOS technology,and was simulated with Cadence SpectreRF.The simulation results indicate that the conversion gain is 6.37dB,the noise figure is 15.36dB and the input 1dB compression point is -10.3dBm,while consuming 1mA current for operating voltage at 1V.

关键词：混频器；电流再利用；低电压；低功耗

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OH Laser Induced Fluorescence (LIF) and picosecond (ps), broadband Coherent Anti-Stokes Raman Spectroscopy (CARS) are used for time-resolved temperature and time-resolved, absolute OH number density measurements in lean H2-air, CH4-air, C2H4-air, and C3H8-air mixtures in a nanosecond (ns) pulse discharge cell/plasma flow reactor. The premixed fuel air flow in the reactor, initially at T0 = 500 K and P = 100 torr, is excited by a repetitive ns pulse discharge in a plane-to-plane geometry (peak voltage 28 kV, discharge gap 10 mm, estimated pulse energy 1.25 mJ/pulse), operated in burst mode at 10 kHz pulse repetition rate. In most measurements, burst duration is limited to 50 pulses, to preclude plasma-assisted ignition. The discharge uniformity in air and fuel air flows is verified using sub-ns-gated images (employing an intensified charge-coupled device camera). Temperatures measured at the end of the discharge burst are in the range of T = 550 600 K, using both OH LIF and CARS, and remain essentially unchanged for up to 10 ms after the burst. Time-resolved temperature measured by CARS during plasmaassisted ignition of H2-air is in good agreement with kinetic model predictions. Based on CARS measurement, vibrational nonequilibrium is not a significant factor at the present conditions. Time-resolved, absolute OH number density, measured after the discharge burst, demonstrates that OH concentration in C2H4-air, C3H8-air, and CH4 is highest in lean mixtures. In H2-air, OH concentration is nearly independent of the equivalence ratio. In C2H4-air and C3H8-air, unlike in CH4- air and in H2-air, transient OH-concentration overshoot after the discharge is detected. In C2H4-air and C3H8-air, OH decays after the discharge on the time scale of 0.02 0.1 ms, suggesting little accumulation during the burst of pulses repeated at 10 kHz. In CH4-air and H2-air, OH concentration decays within 0.1 1.0 ms and 0.5 1.0 ms, respectively, showing that it may accumulate during the burst.

关键词：荧光；动力学；激光；低温；混合物

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Various modes of severe plastic deformation (SPD), such as high-pressure torsion (HPT) at cryogenic temperature, equal channel angular pressing (ECAP) and dynamic channel-angular pressing (DCAP), have been applied for nanostructuring of Ni, and the thermal stability of the structure obtained has been studied. The nanocrystalline structure with average grain sizes of 80 nm and the microhardness of 6200 MPa is produced by HPT in liquid nitrogen. DCAP and ECAP result in the submicrocrystalline structure of a mixed type, with ultra-fine grains separated by high-angle boundaries along with deformation bands and coarse cells with low-angle dislocation boundaries. The thermal stability of the structures obtained by ECAP and DCAP is approximately the same, and it is higher than after the HPT at cryogenic temperature.

关键词：电极材料；纳米晶体；塑性形变

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As a first step towards a microscopic understanding of single-Pt atom-dispersed catalysts on non-conventional TiN supports, we present density- functional theory (DFT) calculations to investigate the adsorption properties of Pt atoms on the pristine TiN(100) surface, as well as the dominant influence of surface defects on the thermodynamic stability of platinized TiN. Optimized atomic geometries, energetics, and analysis of the electronic structure of the Pt/TiN system are reported for various surface coverages of Pt. We find that atomic Pt does not bind preferably to the clean TiN surface, but under typical PEM fuel cell operating conditions, i.e. strongly oxidizing conditions, TiN surface vacancies play a crucial role in anchoring the Pt atom for its catalytic function. Whilst considering the energetic stability of the Pt/TiN structures under varying N conditions, embedding Pt at the surface N-vacancy site is found to be the most favorable under N-lean conditions. Thus, the system of embedding Pt at the surface N-vacancy site on TiN(100) surface could be a promising catalyst for PEM fuel cells.

关键词：燃料电池；原子吸附；计算缺陷

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The ultimate goal of this project is to develop a viable C-coating process of the current collector in order to improve the overall power performance of the electrode of Li-ion batteries. During this third-year period, the performance of different thickness of carbon coating on Al foil is compared. The result shows that only the samples with sufficient thickness to form conductive channel on the surface would give a positive effect on the performance. Scale up of this coating process is further developed to make 1.5 m long C-coated tape by a contentious process followed with a special batch thermal process called roll-calcination. The same positive effects seen on small samples have been reproduced.

关键词：碳涂层电流收集器；化学汽相淀积；锂离子二次电池；蓄电池

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