Electronic origin of the step-like character of the discharge curve for NaxCoO2-y cathode

This paper shows electronic approach to an explanation of the step-like character of the discharge/charge curve of Na / Na +/ Na x CoO 2-y battery. On a basis of comprehensive experimental studies of physicochemical properties of Na x CoO 2-y cathode material (XRD, electrical conductivity, thermoelectric power, electronic specific heat) supported by calculations performed using the Korringa–Kohn–Rostoker method with the coherent potential approximation to account for chemical disorder, it has been shown that the observed step-like character of the discharge curve reflects the variation of the chemical potential of electrons (Fermi level) in the density of states of Na x CoO 2-y, which is anomalously perturbed by a presence of the oxygen vacancy defects and sodium ordering.

Study of the Design Method for The Shape of Charge Curve of the Double Focusing Warhead

For the prefab fragments, firstly, according to the requirements of focusing regions and width at the lethal radius ,the method of pushing down has been used to design the shape of charge curve of the double focusing warhead initiated in the center of the warhead. Then, the warhead with this charge curve designed has been simulated by AUTODYN-3D.The results show that the charge curve designed which is divided into several independent arcs could satisfy the focusing effect. The design method is of great value to the engineering design for other kinds of warhead.

Soil organic carbon, permanganate fractions, and the chemical properties of acidic soils

Total organic carbon (TC) in 32 acidic surface (0–10 cm) soils was divided into 3 fractions (C1, C2, and C3) based on oxidisability by different strengths of KMnO4 (33 mM and 167 mM). With the methodology used, ease of oxidation decreased in the order C1>C2>C3. Several fundamental soil chemical properties were also determined, i.e. ECEC, CEC at pH 6·5 (CEC6·5), slope of the charge curve (ΔCEC), pH buffer capacity, (pHBC), P sorption capacity using a single addition index (PSI150), and content of organically complexed Al. All soils had pH (1:5 water) <6·5, and comprised a wide range of soil types and clay contents. Multiple step-up regression indicated that C fractions were significantly (P < 0·05) correlated with ECEC, ΔCEC, CEC6·5, and pHBC. These results reinforce the critical importance of soil organic matter to the fundamental soil chemical properties of predominantly variable charge soils. The intercorrelations between the various oxidisable C fractions made it difficult to elucidate if degree of oxidisability had any bearing on the reactivity of the organic matter. ECEC was primarily correlated with C1, whereas all C fractions had highly significant (P < 0·01) effects on ΔCEC and pHBC. The fraction which was most difficult to oxidise, C3, made a significant (P < 0·01) contribution to CEC6·5 when combined with clay and ECEC in a multiple regression equation. Generally, one or other of the C fractions was better correlated with the fundamental soil chemical properties than TC. This simple empirical fractionation of soil organic C may therefore be a useful tool for assessing the effects of soil management on these properties.

Use of Charge Curve Analysis Technique for In Vivo Determination of Corrosion Rates

Type 316L stainless steel, commercially pure Ti (75A, TCA), and Ti-0.2Pd bone plates were attached to the femurs of adult New Zealand white rabbits using nylon screws. Corrosion rate-time determinations were conducted using linear polarization (LP) and charge curve analysis (CCA) techniques during 2160 hours following surgery. Of the materials tested, Ti-0.2Pd seems to be the most corrosion resistant and Type 316L stainless steel the least. At the end of the test period (90 days), corrosion rates (in mpy) were in the order of 0.02 for 316L SS, 0.005 for Ti and 0.001 for Ti-0.2Pd. Very good correlation was obtained between determinations made with LP and MCCA. Histopathologic examination of the bone plates and surrounding tissues were conducted. All plates were surrounded by a fibrous tissue capsule. Adverse tissue reaction was minimal.

THE VALENCE OF CORPUSCULAR PROTEINS

By the use of two extreme models: a hydrated sphere and an unhydrated rod the valence (net charge) of corpuscular proteins can be successfully calculated from electric mobility data by the Debye-Hückel theory (modified to include the effect of the ions in the ion atmosphere) in conjunction with the electrophoretic theory of Henry. As pointed out by Abramson, this permits a comparison with values for the valence from titration data. Electrometric titration measurements of serum albumin B (Kekwick) have been determined at several ionic strengths. These results, together with the available data in the literature for serum albumin B, egg albumin, and ß-lactoglobulin have been used to compare values for the valence calculated from measurements of titration, electrophoresis, and membrane potentials. The results indicate that the usual interpretation of titration curves is open to serious question. By extrapolation of the titration data to zero ionic strength and protein concentration, there results an "intrinsic" net charge curve describing the binding of H+ (OH-) ion alone. This curve agrees closely, in each case, with values of the valence calculated from mobility data (which in turn are in close accord with those estimated from membrane potential measurements). The experimental titration curves in the presence of appreciable quantities of ions and protein deviate widely from the ideal curve. It is suggested that, under these conditions, binding of undissociated acid (base) leads to erroneous values for the net charge. This binding would not affect the electrophoretic mobility. Values of the net charge obtained by the two extreme models from electrophoretic data are in agreement within 15 to 20 per cent. The agreement between the cylindrical model and the titration data is somewhat better in each case than with the sphere; i.e., this comparison enables a choice to be made between asymmetry and hydration in the interpretation of results from sedimentation and diffusion measurements on proteins. It is concluded that the proteins discussed here are somewhat asymmetric and also hydrated.