Background The vast majority of research into solid-state polymer electrolytes for low-temperature (o200 1C) fuel cells has focused on proton-exchange membrane (PEM) fuel cells (PEMFCs). Recently, there has been interest in the application of the analogous anion-exchange membranes (AEMs), in alkaline forms, in low-temperature fuel cells (Figure 1).
Heat treatment and surface engineering are seen as crucial elements in the design and manufacture of strategic components in a wide range of market sectors and industries including air, sea and land transportation, energy production, mining, defense or agriculture. This book offers a broad review of recent global developments in an application of thermal and thermochemical processing to modify the microstructure and properties of a wide range of engineering materials.
As a proton-exchange membrane fuel cell (PEMFC) can be started instantly at ambient temperatures and can work with air as oxidant without carbon dioxide problems, it is so far the most viable fuel cell (FC) system that has the potential to replace internal combustion engines (ICEs) and batteries for transportation applications to power cars, buses, and personal electric vehicles (PEVs). This article focuses on the application of this technology for light traction vehicles, such as scooters, bicycles, forklifts, wheelchairs, and tour carts.
Hydrogen, as an energy carrier, is widely regarded as a potential cost effective, renewable, and clean energy alternative to petroleum in order to mitigate energy shortage and global climate warming issues that the world is currently facing. However, storage of hydrogen is a substantial challenge, especially for applications in vehicles with fuel cells that use proton-exchange membranes (PEMs). Therefore, scientific community has started focusing their research activities on developing advanced hydrogen storage materials through nanotechnology. ...
To shed light on the mechanism of isotopic exchange of
a-protons in amino acids catalyzed by pyridoxal phosphate
(PLP)-dependent enzymes, we studied the kinetics of
quinonoid intermediate formation for the reactions of
tyrosine phenol-lyase with L-phenylalanine, L-methionine,
and theira-deuterated analogues inD2O, andwe compared
the results with the rates of the isotopic exchange under the
same conditions.Wehave found that, in theL-phenylalanine
reaction, the internal returnof thea-proton is operative, and
allowing for its effect, the exchange rate is accounted for
Nếu sử dụng chất khí khác (ví dụ khí trơ, CO2, N2) thì không xảy ra proton hoá mμ xảy ra trao đổi điện tích (charge exchange CE) : [He]+ + M → [M]+ + He
− Các phản ứng khác như cộng ái điện tửPhương pháp CI có thể đo đ−ợc các ion phân tử vμ do đó xác định được trọng lượng phân tử. − Đầu tiên, một chất khí (ví dụ hydrocacbon, H2, H2O, NH3, alcol, khí trơ) qua va chạm với electron sẽ bị ion hoá (áp suất khí ≈ 1 kPa)...