To understand the basic properties of lithium secondary batteries which consist of nonflammable and nonvolatile room-temperature ionic liquid electrolytes, we examined the ionic conductivity, electrolyte/electrode interfacial resistance, and charge-discharge rate characteristics by varying the lithium salt concentration in the room-temperature ionic liquid, lithium salt binary electrolytes. By using a modified imidazolium cation-based room-temperature ionic liquid as an electrolyte, the lithium secondary batteries achieved a stable charge-discharge operation of more than
100cycles
(cathode
LiConormalO2
, anode lithium metal, voltage region
3.0–4.2V
, current density
1∕8C
). Moreover, we found that an optimal lithium salt concentration exists for obtaining an excellent battery rate performance, which depends on delicate balances in several factors, such as ionic conductivity (viscosity), interfacial resistances at the
LiConormalO2
cathode/electrolyte interface, and the lithium metal anode/electrolyte interface.
Infrequent structural fluctuations of a globular protein is seldom detected and studied in detail. One tyrosine ring of HPr from Staphylococcus carnosus, an 88-residue phosphocarrier protein with no disulfide bonds, undergoes a very slow ring flip, the pressure and temperature dependence of which is studied in detail using the on-line cell high-pressure nuclear magnetic resonance technique in the pressure range from 3 MPa to 200 MPa and in the temperature range from 257 K to 313 K. The ring of Tyr6 is buried sandwiched between a -sheet and ␣-helices (the water-accessible area is less than 0.26 nm 2 ), its hydroxyl proton being involved in an internal hydrogen bond. The ring flip rates10 Keywords: high pressure; NMR spectroscopy; ring flips; HPr; PTS The intimate relationship between the dynamics and function of a protein has been extensively discussed in the past and is still an exciting field in protein science. Spin relaxation in NMR spectroscopy has proven to be useful for investigating the average microscopic dynamics of a protein occurring in the frequency range normally of 10 9 sec −1 or higher. Various lines of evidence derived from hydrogen exchange experiments (Woodward et al. 1982(Woodward et al. , 2004 Englander and Moyne 1992) and advanced spin relaxation analysis (Ishima and Torchia 2000;Frans et al. 2001;Meiler et al. 2003) indicate that slower motions in the time range of milliseconds to microseconds are widely involved in protein dynamics under conditions that stabilize the folded state. In many cases, slower and rare fluctuations in microseconds to
We report on the first successful output of electrons directly from photosystem I (PSI) of thermophilic cyanobacteria to the gate of a field-effect transistor (FET) by bypassing electron flow via a newly designed molecular wire, i.e., artificial vitamin K(1), and a gold nanoparticle; in short, this newly manufactured photosensor employs a bio-functional unit as the core of the device. Photo-electrons generated by the irradiation of molecular complexes composed of reconstituted PSI on the gate were found to control the FET. This PSI-bio-photosensor can be used to interpret gradation in images. This PSI-FET system is moreover sufficiently stable for use exceeding a period of 1 year.
To understand the behaviors of phosphoric acids in fuel cells, the ion conduction mechanisms of phosphoric acids in condensed states without free water and in a monomer state with water were studied by measuring the ionic conductivity (sigma) using AC impedance, thermal properties, and self-diffusion coefficients (D) and spin-lattice relaxation times (T1) with multinuclear NMR. The self-diffusion coefficient of the protons (H+ or H3O+), H2O, and H located around the phosphate were always larger than the diffusion coefficients of the phosphates and the disparity increased with increasing phosphate concentration. The diffusion coefficients of the samples containing D2O paralleled those in the protonated samples. Since the 1H NMR T1 values exhibited a minimum with temperature, it was possible to determine the correlation times and they were found to be of nanosecond order for a distance of nanometer order for a flip. The agreement of the ionic conductivities measured directly and those calculated from the diffusion coefficients indicates that the ion conduction obeys the Nernst-Einstein equation in the condensed phosphoric acids. The proton diffusion plays a dominant role in the ion conduction, especially in the condensed phosphoric acids.
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