纳米复合质子传导膜中温硫化氢固体氧化物燃料电池的研究

应用溶胶-凝胶法制备了中温硫化氢固体氧化物燃料电池的纳米复合质子传导膜。用SEM和EDX对纳米复合膜进行了观察和表征,并与传统工艺制备的电解膜(微米级)的性能进行了比较。探讨了微米级和纳米级的复合Li2SO4 Al2O3膜的离子传导性随温度变化规律。与传统的工艺采用相同组分制备的微米级电解膜相比,纳米复合膜的微观结构、致密性、机械强度和离子传导性均得到改善,而最显著改善是膜的离子传导性能。纳米复合Li2SO4 Al2O3膜的中温硫化氢固体氧化物燃料电池的性能较稳定,察觉不到膜两侧的气体穿过膜扩散到另一侧。在750℃和101.13kPa下,电池的最大输出功率密度为135mW.cm-2,最大电流密度为480mA.cm-2。     

A turbulent wake as a tracer of 30,000 years of Mira's mass loss history

Mira is one of the first variable stars ever discovered and it is the prototype (and also the nearest example) of a class of low-to-intermediate-mass stars in the late stages of stellar evolution. These stars are relatively common and they return a large fraction of their original mass to the interstellar medium (ISM) (ref. 2) through a processed, dusty, molecular wind. Thus stars in Mira's stage of evolution have a direct impact on subsequent star and planet formation in their host galaxy. Previously, the only direct observation of the interaction between Mira-type stellar winds and the ISM was in the infrared. Here we report the discovery of an ultraviolet-emitting bow shock and turbulent wake extending over 2 degrees on the sky, arising from Mira's large space velocity and the interaction between its wind and the ISM. The wake is visible only in the far ultraviolet and is consistent with an unusual emission mechanism whereby molecular hydrogen is excited by turbulent mixing of cool molecular gas and shock-heated gas. This wind wake is a tracer of the past 30,000 years of Mira's mass-loss history and provides an excellent laboratory for studying turbulent stellar wind-ISM interactions.     

Biological scaling: does the exception prove the rule?

Reich et al. report that the whole-plant respiration rate, R, in seedlings scales linearly with plant mass, M, so that R=C(R)M(theta) when theta approximately 1, in which c(R) is the scaling normalization and theta is the scaling exponent. They also state that because nitrogen concentration (N) is correlated with c(R), variation in N is a better predictor of R than M would be. Reich et al. and Hedin incorrectly claim that these "universal" findings question the central tenet of metabolic scaling theory, which they interpret as predicting theta = (3/4), irrespective of the size of the plant. Here we show that these conclusions misrepresent metabolic scaling theory and that their results are actually consistent with this theory.     

Common genetic variants at the CRAC1 (HMPS) locus on chromosome 15q13.3 influence colorectal cancer risk

We mapped a high-penetrance gene (CRAC1; also known as HMPS) associated with colorectal cancer (CRC) in the Ashkenazi population to a 0.6-Mb region on chromosome 15 containing SCG5 (also known as SGNE1), GREM1 and FMN1. We hypothesized that the CRAC1 locus harbored low-penetrance variants that increased CRC risk in the general population. In a large series of colorectal cancer cases and controls, SNPs near GREM1 and SCG5 were strongly associated with increased CRC risk (for rs4779584, P = 4.44 x 10(-14)).     

中温质子传导膜H2S燃料电池电极催化剂

研究了基于三相边界层理论设计的中温质子传导膜H2S燃料电池的阳极与阴极催化剂.考察了3种阳极催化剂Pt、MoS2及复合金属硫化物(MoS2/N iS)电化学氧化硫化氢的性能和在硫化氢环境下的化学稳定性,发现MoS2和复合MoS2/N iS催化剂比Pt具有更好的催化活性,但MoS2在温度超过450℃时会升华,而含有Mo和过渡金属N i的复合MoS2/N iS催化剂在操作条件下很稳定.文中还研究了两种阴极催化剂Pt与复合N iO催化剂的电化学性能,发现复合N iO催化剂比Pt电极具有更低的过电位和更好的电化学性能;虽然复合电极的导电性比Pt差些,但是这一问题可以通过在电极中掺杂10%的Ag粉解决.由H2S、(MoS2 N iS Ag 电解质 淀粉)/Li2SO4-A l2O3/(N iO Ag 电解质 淀粉)、空气构成的燃料电池在101.13 kPa和600~680℃下的电化学特性研究表明,电池最大输出电流密度和功率密度在680℃时分别达到240mA/cm2和70mW/cm2.     

Disciplining cattle reproduction: Veterinary reproductive science,bull infertility,and the mid-twentieth century transformation of Swedish dairy cattle breeding

From the 1940s, reproductive physiology and livestock genetics transformed dairy cattle breeding and became, in conjunction with the new reproductive technology of artificial insemination, important drivers of agricultural modernization in most countries with significant dairying. While this is well known, we know less about the longer-term interplay between specifically veterinary interests in reproduction and the institutional development of cattle breeding. In the present paper, I therefore examine the veterinary disciplining of cattle reproduction—its constitution as a veterinary scientific discipline and the extension of veterinary control over it—in mid-twentieth century Sweden. I show how veterinary scientists derived legitimacy for their fledgling discipline by engaging with the problems of practical breeding, and that in doing so they also exercised influence over breeding’s development. By making bulls’ reproductive disturbances visible and framing them as hereditary, they undermined the conservative interests of commercial breeders. The development of veterinary reproductive science thereby played an important role in reshaping the culture, economy, and regulations of cattle breeding in Sweden as it shifted from a prewar regime dominated by elite breeders to a postwar regime that, ostensibly, served all dairy farmers in the country.     

Influence of soil frost on infiltration of shrub coppice dune and dune interspace soils in southeastern Nevada

The influence of soil frost on the infiltration rate of shrub coppice dune and dune interspace soils was evaluated near Crystal Springs, Nevada, using simulated rainfall. The infiltration rate of the coppice dune soil was greater than the dune interspace soil under frozen or unfrozen conditions. Because of different vegetation cover and surface soil characteristics, coppice dune and dune interspace soils responded differently to freezing, thus imposing a spatial and temporal response to infiltration rate. Infiltration rate of soils with porous concrete frost increased as the soils thawed during simulated rainfall, but soils with nonporous concrete frost allowed very little infiltration to occur. Both coppice dune and dune interspace soils that were classified in January as having granular frost had a higher infiltration rate than the same unfrozen soils in March.     

Die Ligninsulfosäure und ihre technische Verwertung

Summary For a long time the lignin-sulfonic acids, obtained in very large quantities in the manufacture of sulphitepulp, have engaged the interest of chemical research workers for economic and scientific reasons. for both fields the determination of the constitution of the lignin-sulfonic acids and the knowledge of the processes taking place between lignin and sulfonic acid are of basic importance.During the last years our institute was able to gain a broader conception of the whole problem by means of model experiments, For the first time it was possible to achieve progress in this direction through a combination of oxidative and hydrolytic decomposition and the complete elimination of the sulfonic acid radical.Although researchers of the whole world have been working on this problem for years, no progress of any greater importance in the utilization of lignin-sulfonic acid has been made. Nevertheless experiments on the production of artificial materials from lignin-sulfonic acid as a base are very promising. By high pressure hydrogenation valuable products are obtained, although at high costs. The production of vanillin is far advanced (especially in the United States) and yields a new success of by-products which may be used with much success in combination with artificial materials, e.g. press plates.

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Aus dem I. Chem. Laboratorium der Universität Wien, Organische Abteilung und Abteilung für Chemie des Holzes. Diese Arbeit schließt sich an die Publikation vonA. v. Wacek, Exper. 2, 171 (1946), an.     

An outline of the varieties of the second-order systems sciences

The systems sciences are based on a universal language of systems which can be used within most academic disciplines in their endeavors for exploring the world. Currently, systems sciences cover a wide variety of different approaches like complex adaptive systems, resilient systems or systems engineering. One of the future extensions of the systems sciences comes through the applications of second-order systems science as a new field of reflexive studies on first-order systems science. This article provides a general background on the relations of first-order science and second-order science in general and then goes on to sketch a basic outline for the second-order systems sciences and their potentials for quality control and for innovations for the first-order systems sciences.