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排序方式: 共有6049条查询结果,搜索用时 234 毫秒
941.
Xavier Ravalec Nathalie Le Tallec François Carré Jacques D. de Certaines Elisabeth Le Rumeur 《Magma (New York, N.Y.)》1999,9(1-2):52-58
Kinetics of phosphoryl transfers from PCr to γ-ATP and from β-ATP to β-ADP were measured by magnetization transfer in an in
vivo31P NMR experiment in working rat skeletal hind leg muscles. Two groups were examined. One group was submitted to a 6-week training
program of treadmill running. The other group was composed of sedentary animals. Metabolic oxidative capacity and mechanical
performance were improved greatly by training as shown previously. Phosphoryl transfer of PCr→γ-ATP or β-ATP→β-ADP total fluxes
were identical in resting trained and untrained muscles. Under stimulation, the flux of creatine kinase transfer was significantly
inhibited by 23% compared with resting level in untrained muscles; by contrast, it was not inhibited and maintained at the
high resting level in trained muscles. Thus physiological changes probably linked to a decrease of the production of anions,
which could inhibit creatine kinase, were able to maintain creatine kinase flux. The flux of β-ATP to β-ADP transfer were
enhanced largely in working muscles from 1.4±0.8 and 2±0.8 at rest to 4±1.6 and 6.6±2.7 mM s−1 for untrained and trained muscles respectively; the effect was more pronounced in trained than in untrained muscles. These
results showed an acceleration of phosphoryl turnover in working muscles after training, which could contribute to improve
oxidative and mechanical performances. Such kinetic measurements of phosphoryl conversion may provide information on ATP turnover
in pathophysiologic situations where ADP accumulates because of impaired ATP synthesis (mitochondrial myopathies, lower perfusion
level). 相似文献
942.
943.
944.
Ayşenur Öztürk Berker Fıçıcılar İnci Eroğlu Ayşe Bayrakçeken Yurtcan 《International Journal of Hydrogen Energy》2017,42(33):21226-21249
Microporous layers (MPLs) were prepared with different hydrophobic polymers to establish water management in polymer electrolyte membrane (PEM) fuel cells. Besides conventionally used polymers polytetrafluoroethylene (PTFE) and fluorinated ethylene propylene (FEP), two different molecular weights (MW) of polydimethylsiloxane (PDMS) polymer were used as hydrophobic materials in MPL. Membrane electrode assemblies (MEAs) having MPLs with low MW PDMS polymer exhibited the best fuel cell performance compared to the PTFE and FEP based ones. Thus it is concluded that PDMS polymer has a great potential to be used as hydrophobic material for MPL to reduce flooding phenomena in PEM fuel cell. 相似文献
945.
946.
Kerimcan Çelebi Erinç Uludamar Mustafa Özcanlı 《International Journal of Hydrogen Energy》2017,42(36):23379-23388
Viscosity property of a fuel is a crucial point for internal combustion engine characteristics. Performance and emission parameters as well as injector's life of an engine is primarily effected by viscosity of the fuels. In present study, effect of high viscosity biodiesel fuels with hydrogen addition was investigated in a compression ignition engine. Biodiesels that are produced from Pongamia Pinnata and Tung oils were used as pure biodiesels as well as blended with low sulphur diesel fuel at the volume ratios of 50% and 75%. Furthermore, hydrogen gas was injected into intake manifold in order to evaluate its effect with the usage of high viscous liquid fuels. The results revealed that brake specific fuel consumption was increased with biodiesel fuels, whereas hydrogen addition into intake manifold improved the consumption. Total vibration acceleration of the engine reduced with biodiesel and hydrogen additions. Frequency spectrum indicated that this decrement was primarily lowered due to less energy transmitted through engine pistons that converted from chemical energy of fuels. 相似文献
947.
George Chatzipirpiridis Carmela de Marco Eva Pellicer Olgaç Ergeneman Jordi Sort Bradley J. Nelson Salvador Pané 《Advanced Engineering Materials》2018,20(9)
948.
949.
Mechanical Properties and Microstructural Characterization of Aged Nickel-based Alloy 625 Weld Metal
Silva Cleiton Carvalho de Albuquerque Victor Hugo C. Miná Emerson Mendonça Moura Elineudo P. Tavares João Manuel R. S. 《Metallurgical and Materials Transactions A》2018,49(5):1653-1673
Metallurgical and Materials Transactions A - The aim of this work was to evaluate the different phases formed during solidification and after thermal aging of the as-welded 625 nickel-based alloy,... 相似文献
950.