Structure analysis of anode flow field of micro direct methanol fuel cell based on Fluent

微型直接甲醇燃料电池中阳极流场结构对电池的性能有着重要的影响。为了合理设计阳极流场结构,改善甲醇燃料在阳极流场中的分布,采用计算流体动力学(Cfd)软件fluEnT对微型直接甲醇燃料电池进行建模并仿真分析。分析比较了点型、平行和蛇形3种不同流场图案下得到的压降与流速分布,得出蛇形流场能够更有利于甲醇燃料的均匀分配。在此基础上分别建立不同流道宽度(800,400,200,100μM)的蛇形流场模型,通过仿真计算甲醇燃料的分布情况来分析其对燃料电池性能的影响,并结合实验结果进行对比得出流道宽度为200~400μM之间为优化值。Structure of anode flow field is very important for micro direct methanol fuel cell.To optimize the structure of the anode flow field and the distribution of methanol in it,a model of micro direct methanol fuel cell is created and analyzed by using the computational fluid dynamics(CFD) software.The influence of flow field shapes of grid,parallel and serpentine are analyzed and the pressure drop and velocity distribution in the three kinds of flow fields are studied.It shows that the flow field of serpentine is the best for the even distribution of fuel.Based on this,serpentine flow field models with different width(800,400,200 and 100 μm) are created.Simulations are taken to analyze the influence of distribution to cell performance and compared with experimental results,it shows that the optimal value of flow channel width is 200 ~400 μm.国家自然科学基金重点资助项目(60936003

Development and Application of a Novel Neutralization Test for Echovirus 25

目的:建立一种新型的快速、高通量的埃可病毒25型(ECHO25)中和抗体检测方法,并初步评价其在ECHO25中和抗体筛选和血清流行病学调查中的应用价值。方法:应用免疫荧光方法筛选ECHO25高亲和性抗体并将其作为检测单抗,结合酶联免疫斑点检测技术(ELISPOT)建立ECHO25中和抗体检测方法;使用不同效价的血清评价该方法的准确性;采用所建立的中和方法对ECHO25单克隆抗体、临床血清样品进行检测。结果:建立了快速检测ECHO25中和抗体的Nt-ELISPOT方法,以ECHO25单克隆抗体5B9作为检测抗体;相比经典的中和实验方法 Nt-CPE,该方法可显著缩短检测时间(从5~7 d缩短至1 d以内),检测结果具有较好的一致性;采用所建立的Nt-ELISPOT方法首次筛选获得3株对ECHO25具有较好中和能力的单克隆抗体;临床血清样品检测结果显示厦门地区可能存在ECHO25的流行。结论:该方法可以应用于中和抗体筛选和血清学的临床辅助诊断,为ECHO25的防治研究提供支持。Objective: To establish a rapid and high-throughput neutralization test for echovirus 25(ECHO25),and evaluate its application in neutralizing antibody screening and seroepidemiological surveys. Methods: Immuno-fluorescence assay was applied to screen a high affinity antibody, which was used as the detection antibody forECHO25, and a rapid neutralization test was established based on enzyme- linked immunospot assay(Nt-ELISPOT). The accuracy of this method was evaluated by detecting serum samples with different titer. Monoclonalantibodies against ECHO25 and clinical serum samples were detected via the established neutralization test. Results: A rapid method to detect neutralizing antibody against ECHO25 was established and an anti-ECHO25 anti-body, 5B9, was used as the detection antibody. The detection period could be shortened significantly comparedwith the classical neutralization test(Nt- CPE)(from five to seven days to less than one day), and the Nt-ELISPOT had good consistency with the Nt- CPE. Meanwhile, three neutralizing antibodies for ECHO25 werescreened firstly by this method. The detection results of clinical serum samples showed that infection of ECHO25 might be popular in Xiamen. Conclusion: This method can be used in neutralizing antibody screening and seroepi-demiological surveys, and it may provide support for the control of ECHO25.国家自然科学基金(81371817,81401669

Design and Fabrication of Stack Micro-Direct Methanol Fuel CellUsing Silicon and PDMS

在堆栈式微型直接甲醇燃料电池μ-dMfC(MICrO-dIrECT METHAnOl fuEl CEll)中,为了避免硅基流场板因为封装压力过大而破裂,采用了硅和PdMS(POlydIMETHylSIlOXAnE,聚二甲基硅氧烷)材料分别制作阳极和阴极流场板。首先,采用微机电系统MEMS(MICrO-ElECTrO-MECHAnICAl SySTEMS)技术制作硅基阳极流场板。其次,通过铜箔与阴极流场板一体成型、有机清洗和PdMS表面活化等改进措施显著提升了PdMS阴极流场板金属化的能力。最后,比较和分析阳极流场板上3种不同结构的流道形式的堆栈式μ-dMfC的输出性能。实验结果表明,活化后的PdMS阴极流场板与Cr/Au的粘附性能和粘接强度显著提高,同时阳极流场板的流道一半开设为凸台,一半开设为通孔时,其堆栈式μ-dMfC的输出性能最优。最大输出电流密度为81.25 MA/CM2,最大输出功率为7.73 MW/CM2。采用硅和PdMS材料分别制作流场板,不仅简化了堆栈式μ-dMfC的结构,而且能够缓冲锁紧力,有效保护硅基阳极流场板。同时优化阳极流场板上的流道结构,能够有效提升堆栈式μ-dMfC的输出性能。In order to avoid cracks of the silicon flow field plate caused by high package pressure,silicon and PDMS(Polydimethylsiloxane)are used as anodic and cathode flow field plate respectively in the stack μ-DMFC(Micro-direct methanol fuel cell).The anodic flow field plate based on silicon is fabricated with MEMS(Micro-Electro-Mechanical Systems)technology,and cathode flow field plate is fabricated using PDMS and its metallic performance is evidently improved by means of integral shaping of copper foil and cathode flow field plate,organic cleaning and activation on PDMS surface.The output of stack μ-DMFC is tested and analyzed,in which 3 different flow channel structures on the anodic plate are introduced.Tested results verify that adhesive capability and strengthen between post-activated PDMS and Cr/Au are greatly improved,and when micro blocks and through holes are introduced alternately in the flow channel of anodic flow field plate the stack μ-DMFC can obtain the maximum output,with voltage of 0.5 V,current density of 81.25 mA/cm2 and output power density of 7.73 mW/cm2.This study shows that using silicon and PDMS as flow field plate respectively not only simplifies the structure of stack μ-DMFC but also cushions clamping force and effectively protects anodic flow field plate,and furthermore to increase the output of stack μ-DMFC by optimizing structure of flow channels on the anodic flow field plate.国家自然科学基金重点项目(60936003

Some characteristics of energy exchange at the underlying surface of desert and oasis in Hexi Corridor

在河西走廊黑河地区沙漠和绿洲下垫面生态条件下,用涡旋相关法研究了能量输送的不同模式和日变化进程;以及两种生态条件下能量输送间可能存在的相互关系。在沙漠生态条件下,大部分净辐射用于显热散失,另一部分用于向地下传输,较少部分则用于潜热输送,其方向在白天向下,在夜间向上;其Bowen比为13.16。在绿洲的麦田生态条件下,能量输送的基本模式为:大部分净辐射用于潜热散失,其输送方向与沙漠相反,另一部分用于显热散失,其输送方向一般在午后约3h即由上传转为下传。土壤热通量在最大时一般不超过40W/m2。冠层光合作用固定的能量则更小,其数量级维持在10W/m2以下,小麦不同生长阶段各能量分量占净辐射的比例有所变化。麦田的Bowen比从分蘖期的0.33降到拔节期末的0.095。当有干热大风自沙漠吹向绿洲时观测了典型的绿洲效应,其能量输送模式发生很大变化,显热显著下传,地热流量减弱,潜热散失强烈,起风后约2h潜热甚至高于净辐射。表明沙漠的能量组分参与了麦田的能量平衡过程。 【英文摘要】 With eddy correlation,we studied the pattern and dinurnal variation course of energy transfer for the underlying surface of desert and wheat field in oasis and their possible relationship between two ecological conditions at Heihe River region in Hexi Corridor during the HEIFE project.In the desert,the most net radiation( Rn )was consumed by sensible heat( H )transfer,another part of Rn conducted into desert surface,and a small part of Rn was dissipated by latent heat( LE ) transfer on a fine ...中国科学院资助项目;;国家自然科学基金;;日本文部省资助项

Some biometeorological features of wheat field in the ecological conditions of oasis at the Heihe Region

观测分析了 HEIFE地区绿洲中麦田的一些微气候特征 ,结果表明 SPAC中水势随高度呈显著梯度分布 ,在土壤 -植物以及植物 -大气界面 ,水势值存在两个大的跳跃 ;水势廓线存在明显的日变化 ;SPAC各部分水势变化的起伏顺序是大气 >植物 >土壤 ,说明水势变化受植物水分代谢进程直至气象因子的强烈影响和控制。冠层上方近地面风温湿的时空剖面显示出白天与夜晚相比 ,大气混合得较好 ;日出前则大气较为稳定 ;在典型晴天条件下 ,麦田上方的大气存在内边界。其结构受来自沙漠干热风的影响和控制。冠层内部也存在着温度、湿度、CO2 浓度、PAR、蒸腾作用、光合作用、气孔导度和叶温的垂直梯度 ,其廓线的日变化主要受太阳辐射的强烈控制 ,同时也受冠层内部不同层面叶片水分代谢强弱以及土壤状况的影响 ,其温湿廓线表现出与冠层上方不同的变化模式。 【英文摘要】 We observed and analysed some characteristics of biometeorology over and within canopy in spring wheat field in the ecological conditions of oasis during HEIFE program.Water potential in SPAC appeared a well vertical profile and the profile showed an obvious diurnal variation.There were water potential jumps in the SPAC junction boundaries.Sequence of variation intensity for water potential in each part of the SPAC was atmosphere,plant and soil.It is shown that the water potential was influenced and control...中国科学院资助;; 国家自然科学基金!( No.94 870 0 4 );; 日本文部省资助!( No.0 2 0 4 1 0 4 3

Effect of Sustained Applying Organic Matter and Chemical Fertilizer on Improving Fertility of Loessal Soil

连续８年的田间试验及室内分析结果表明：有机无机肥配施增产效应大于两者分别单施效应，有机肥与氮肥配施效果较好，联应值为正值，与磷肥配施效果较差，多数是负联应，与氮磷肥配施显示一定的增产优势。有机无机配施有明显的增肥效应，其中有机肥与氮磷配施效果最佳，施磷上壤有效磷增加，不施肥及单施氮肥土壤养分变化甚微或呈下降趋势

The Residual Effect of Long-term Fertilization and Its Affection onSoil Nutrient in Loessal Soil

在６年长期施Ｎ、Ｐ、Ｍ、ＮＰ、ＭＮ、ＭＰ和ＭＮＰ的土壤上，连续种植一季谷子和两季小麦，研究长期施肥对后茬作物产量和吸Ｎ，Ｐ量的反映及Ｎ，Ｐ养分在作物体内分布情况，盆栽试验结果表明，磷肥、有机肥单施或与其它肥料配施均有后效，纯施Ｎ肥没有后效，而且影响和限制了后茬作物的生长和发育，Ｐ肥的后效最多能维持３年，有机肥后效仅能维持一年，经过三料作物吸收，其土壤有机质、全Ｎ、速效Ｐ和喊解Ｎ均有所降低

Fertilization Effect and Nutrient Cycle Balance Feature of Dryland in Loess Hilly Gully Region

根据多年的研究结果，黄土丘陵沟壑区是Ｎ、Ｐ化肥的高效区，在各种土地类型上，均以配合施用效果高而稳定，养分平衡结果表明，ＮＰ配合施用Ｎ素亏损，川地磷素营养得到改善，有机无机配合施用，土壤肥力全面提高。坡耕地由于水土流失的影响，土壤磷库除有机肥与ＮＰ配施外，均处亏损状态。由此得出，本区必须合理利用土地，建设基本农田，实施有机无机配合施用，达到高产，优质高效及培肥土壤