Forest soil profiles of two dunes within the European belt of inland dunes were analysed in the laboratory. We carried out respirometric measurements of carbon dioxide production and oxygen consumption for every horiz...Forest soil profiles of two dunes within the European belt of inland dunes were analysed in the laboratory. We carried out respirometric measurements of carbon dioxide production and oxygen consumption for every horizon of the studied soils while simultaneously quantifying the organic matter and humidity. Oxygen consumption and carbon dioxide excretion decreased exponentially with depth. The oxygen consumption decrease was less rapid than the decrease in carbon dioxide production. We found a statistical significant linear dependence between oxygen consumption and carbon dioxide excretion, and organic matter content and soil water capacity. Respiration processes in the profiles were divided into two strata;oxygen respiration dominated in the first and fermentation processes in the second. We estimated total respiration in the studied profiles for an area of 1 m2 down to around 1 m depth. We concluded that when assessing the soil’s role in carbon cycling in an ecosystem, it is necessary to consider both the respiratory and fermentation strata, as both produce large quantities of carbon dioxide. The main factor determining carbon dioxide production intensity is organic matter content;thus the distribution of organic matter in the soil profile determines carbon cycling intensity.展开更多
The XRD, TEM, PAT, Curie temperature and internal friction methods were used to study systematically the embrittlement mechanism of rapidly quenched ( RQ ) nanocrystalline soft magnetic alloy Fe73.5Cu1Nb3Si13.5B9.The ...The XRD, TEM, PAT, Curie temperature and internal friction methods were used to study systematically the embrittlement mechanism of rapidly quenched ( RQ ) nanocrystalline soft magnetic alloy Fe73.5Cu1Nb3Si13.5B9.The test results confirmed that the RQ embrittlement mechanism of amorphous alloy FeCuNbSiB was not related to crystallization but that was related to structural relaxation. Furthermore, the structural relaxation temperature of amorphous alloy FeCuNbSiB was much lower than that of used commonly amorphous alloy Fe78B13Si9. It meant that the RQ embrittlement is easier to happen for nanocrystalline alloy FeCuNbSiB than amorphous alloy Fe-B-Si.展开更多
Parametric Accelerated Life Testing (ALT) was used to improve the reliability of ice-maker system with a fractured helix upper dispenser in field. By using bond graphs and state equations, a variety of mechanical load...Parametric Accelerated Life Testing (ALT) was used to improve the reliability of ice-maker system with a fractured helix upper dispenser in field. By using bond graphs and state equations, a variety of mechanical loads in the assembly were analyzed. The acceleration factor was derived from a generalized life-stress failure model with a new load concept. To reproduce the failure modes and mechanisms causing the fracture, new sample size equation was derived. The sample size equation with the acceleration factor also enabled the parametric accelerated life testing to quickly reproduce early failure in field. Consequently, the failure modes and mechanisms found were identical with those of the failed sample. The design of this testing should help an engineer uncover the design parameters affecting the reliability of fractured helix upper dispenser in field. By eliminating the design flaws, gaps and weldline, the B1 life of the redesign of helix upper dispenser is now guaranteed to be over 10 years with a yearly failure rate of 0.1% that is the reliability quantitative test specifications (RQ).展开更多
文摘Forest soil profiles of two dunes within the European belt of inland dunes were analysed in the laboratory. We carried out respirometric measurements of carbon dioxide production and oxygen consumption for every horizon of the studied soils while simultaneously quantifying the organic matter and humidity. Oxygen consumption and carbon dioxide excretion decreased exponentially with depth. The oxygen consumption decrease was less rapid than the decrease in carbon dioxide production. We found a statistical significant linear dependence between oxygen consumption and carbon dioxide excretion, and organic matter content and soil water capacity. Respiration processes in the profiles were divided into two strata;oxygen respiration dominated in the first and fermentation processes in the second. We estimated total respiration in the studied profiles for an area of 1 m2 down to around 1 m depth. We concluded that when assessing the soil’s role in carbon cycling in an ecosystem, it is necessary to consider both the respiratory and fermentation strata, as both produce large quantities of carbon dioxide. The main factor determining carbon dioxide production intensity is organic matter content;thus the distribution of organic matter in the soil profile determines carbon cycling intensity.
基金supported by the National Amorphous and Nanocrystalline Alloy Engineering Research Center in CISRI
文摘The XRD, TEM, PAT, Curie temperature and internal friction methods were used to study systematically the embrittlement mechanism of rapidly quenched ( RQ ) nanocrystalline soft magnetic alloy Fe73.5Cu1Nb3Si13.5B9.The test results confirmed that the RQ embrittlement mechanism of amorphous alloy FeCuNbSiB was not related to crystallization but that was related to structural relaxation. Furthermore, the structural relaxation temperature of amorphous alloy FeCuNbSiB was much lower than that of used commonly amorphous alloy Fe78B13Si9. It meant that the RQ embrittlement is easier to happen for nanocrystalline alloy FeCuNbSiB than amorphous alloy Fe-B-Si.
文摘Parametric Accelerated Life Testing (ALT) was used to improve the reliability of ice-maker system with a fractured helix upper dispenser in field. By using bond graphs and state equations, a variety of mechanical loads in the assembly were analyzed. The acceleration factor was derived from a generalized life-stress failure model with a new load concept. To reproduce the failure modes and mechanisms causing the fracture, new sample size equation was derived. The sample size equation with the acceleration factor also enabled the parametric accelerated life testing to quickly reproduce early failure in field. Consequently, the failure modes and mechanisms found were identical with those of the failed sample. The design of this testing should help an engineer uncover the design parameters affecting the reliability of fractured helix upper dispenser in field. By eliminating the design flaws, gaps and weldline, the B1 life of the redesign of helix upper dispenser is now guaranteed to be over 10 years with a yearly failure rate of 0.1% that is the reliability quantitative test specifications (RQ).
