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991.
Online analysis of products from a direct ethanol fuel cell 总被引:1,自引:0,他引:1
David D. James Dwayne V. Bennett Guangchun Li Azra Ghumman Robert J. Helleur Peter G. Pickup 《Electrochemistry communications》2009,11(10):1877-1880
Methodology for the online analysis of the main products from a direct ethanol fuel cell (DEFC) has been developed. The liquid exhaust from the fuel cell is first passed through a conductivity cell to determine the concentration of acetic acid and then CO2 is extracted into a nitrogen stream for determination with a flow-through infrared-based CO2 sensor. The other major product, acetaldehyde can be obtained by difference from the current. The continuous measurement of these products allows monitoring of changes in product distributions with time and operating conditions, resulting in a simple online system for rapid evaluation of anode catalysts in DEFCs. 相似文献
992.
Multiple-ion-sensing functions are integrated on a capillary-assembled microchip (CAs-CHIP). Since the CAs-CHIPs are fabricated by embedding various chemically functionalized square capillaries onto a lattice PDMS channel plate having same channel dimensions as outer dimensions of square capillaries, integration of parallel multiple-ion-sensing is easily realized. Here, three ion-sensing capillaries are prepared and used for integrating these functions onto a single microchip. Ion-sensing square capillaries (sodium, potassium, calcium) are prepared by attaching ion-selective optode membranes to inner wall of capillaries, and are characterized in terms of response time, response range, and ion selectivity. Finally, fully characterized ion-sensing capillaries are embedded into PDMS channel plate in parallel to fabricate a multiple-ion-sensing chip. The CAs-CHIP-based strategy is promising for integrating multiple chemical sensing functions onto a single microchip. 相似文献
993.
Using piezoresistive SiO2 microcantilever technology, we present an ultra-sensitive chemical sensor for trace organophosphorus vapor detection. A self-assembled composite layer of Cu2+/11-mercaptoundecanoic acid is modified on the surface of the sensing cantilever as a specific coating to capture PO containing compounds. Experimental results indicate that the sensor can be quite sensitive to DMMP vapor (well known as a simulant of nerve agent). The signal-noise-limited detection resolution of the sensor is experimentally obtained as low as several parts per billion. Besides that the sensor can yield reversible and repeatable response to DMMP vapor, adsorption of DMMP on the self-assembled composite layer is well fit to the Langmuir isotherm model. 相似文献
994.
SHAO Jie 《高等学校化学研究》2011,27(5):769-772
A coumarin Shiff-base derivative, salicylaldehyde-N-(6-phenylazo-coumarin-3-formyl)-hydrazone(1), was obtained by simple organic synthesis from cheap and commercially available starting materials. Sensor 1 exhibits a very weak fluorescence emission, however, in the presence of acetate ions “turn-on” fluorescence is observed, which results from binding-induced conformational restriction of the fluorophore. Importantly, sensor 1 can also be used as colorimetric chemosensor for the anions with strong basicity, which is easily observed from yellow to red by naked eyes. Consequently, compound 1 can behave as a colorimetric and fluorescence sensor for biologically important F–, CH3COO– and H2PO4– in the presence of the other anions tested such as Cl–, Br– and I– in dimethyl sulfoxide(DMSO). 相似文献
995.
针对最小采集约束条件和经历长时间跨度下识别率低的问题,提出一种基于MEMS加速度传感器的步态识别算法。该算法以右髋部位置采集加速度信号构造多个高斯差分尺度空间,利用局部关键点生成稀疏表示的步态特征位置模板,并采用模板融合来有效转换稀疏性步态周期特征,最后利用最近邻算法和投票机制对步态特征进行识别。在公开的含175名测试者的步态加速度数据集上进行测试,实验结果显示识别率为98.67%和认证率为99.89%,并进一步研究了测试集和训练集样本数目对识别效果的影响,验证了特征提取的有效性和稳定性。 相似文献
996.
星敏感器是惯性天文组合导航系统的关键传感器,星敏感器的光学系统设计及对杂散光的抑制是决定其能否实现测星的主要因素。提出一种改进型的卡塞格伦反射光学系统,该系统通过摆镜折叠光路并实现扫描,压缩了系统的体积,增强了系统的灵活性。进而针对该系统设计了一种基于基生叶结构的遮光罩,利用光线追迹软件在不同方位和俯仰角度入射下对系统进行了仿真分析,结果表明规避角以外的点源透射比可以达到10?9以下,满足系统使用要求。此外,鉴于传统点源透射比方法的计算量较大,还引入了杂散光系数的概念,通过对镜像系统进行反向光线追迹可以将杂散光分离,从而计算出杂散光系数,表征系统对杂散光的抑制能力。该方法可降低计算量,提高设计效率。 相似文献
997.
Mohammad T. Baei Alireza Soltani Saeedeh Hashemian 《Phosphorus, sulfur, and silicon and the related elements》2016,191(5):702-708
The interaction of hydrazine (N2H4) molecule with pristine and Si-doped aluminum nitride (Al12N12) nano-cage was investigated using the density functional theory calculations. The adsorption energy of N2H4 on pristine Al12N12 in different configurations was about –1.67 and –1.64 eV with slight changes in its electronic structure. The results showed that the pristine nano-cage can be used as a chemical adsorbent for toxic hydrazine in nature. Compared with very low sensitivity between N2H4 and Al12N12 nano-cage, N2H4 molecule exhibits high sensitivity toward Si-doped Al12N12 nano-cage so that the energy gap of the Si-doped Al12N12 nano-cage is changed by about 31.86% and 37.61% for different configurations in the SiAl model and by about 26.10% in the SiN model after the adsorption process. On the other hand, in comparison with the SiAl model, the adsorption energy of N2H4 on the SiN model is less than that on the SiAl model to hinder the recovery of the nano-cage. As a result, the SiN Al12N11 is anticipated to be a potential novel sensor for detecting the presence of N2H4 molecule. 相似文献
998.
针对无线传感器网络资源受限、能量约束问题,提出了ESRAC算法.该算法综合PEGASIS算法及蚁群算法的优点,考虑到全网的能量消耗,将能量因子加入到概率选择模型和信息素更新机制中,构造最短路由.并且利用混沌扰动,使蚁群算法跳离局部最优解,避免路由过程中的热点问题.仿真实验表明该算法更好地节约了全网能量,延长了网络的生命周期. 相似文献
999.
1000.