New Editor-in-Chief,J. Solid State Electrochemistry

Journal of Solid State Electrochemistry -     

Aromatic Polynitro Ether Derivatives of Cellulose

The nucleophilic reaction of sodium cellulosate in the form of membrane or cotton fabric with 2, 4-dinitrohalo-benzenes, 2, 4, 6-trinitrochlorobenzene, 2, 4, 6-trinitrobenzyl bromide, and 2, 4, 6-trinitrostyrene was investigated. The degree of substitution attained with the dinitroaryl derivatives was much higher than that with the trinitroaryl derivatives. The reaction proceeded through Meisen-heimer complexes, which in the case of the trinitro derivatives could be isolated. The ability of the polynitro phenyl ether derivatives of the cellulose to form n- and π-complexes was investigated using naphthalene and p-toluidine. No -π- complex was formed with the former, and the latter gave complexes only with the 2, 4, 6-trinitrobenzyl or -phenethyl cellulose derivatives but not with the trinitrophenyl. The results were explained as due to steric hindrance from the polymeric cellulosic backbone.     

Recent development in the field of ceramics solid-state electrolytes: I—oxide ceramic solid-state electrolytes

Journal of Solid State Electrochemistry - Many elements in the periodic table form ionic compounds; the crystal lattices of such compounds contain cations and anions, which are arranged in the way...     

A critical review-promises and barriers of conversion electrodes for Li-ion batteries

Conversion-type electrode materials are discussed in this critical review. Most of the conversion materials are significantly less expensive than modern intercalation-type materials, and the materials involved are appreciably abundant in the nature. However, up to now, no practically viable battery with conversion material-based electrodes was reported, as there are several major barriers to a practical employment of these materials. First, material utilization and cell energy performance are seriously compromised by a low conductivity of the most conversion materials and by a substantial electrolyte involvement in the electrochemical process. Second, the conversion reactions usually demonstrate a severe volume effect, and also conversion electrodes interact with electrolyte developing thick and resistant solid electrolyte interphase films; both of these features result in impractically low electrode cyclability. Third, a large lithiation/de-lithiation voltage hysteresis results in impractically low charge/discharge energy efficiency and suggests a severe battery heating in the course of the battery operation. All these problems present serious challenges for the researchers in the field; the approaches for handling these issues are discussed in the review. For the foreseeable future, there are grounds to expect progress in tackling some of these issues. The issue of high voltage hysteresis is a bottleneck, though, and it actually precludes conversion materials from any practical application.     

Randomized k-server algorithms for growth-rate bounded graphs

The k-server problem is a fundamental online problem where k mobile servers should be scheduled to answer a sequence of requests for points in a metric space as to minimize the total movement cost. While the deterministic competitive ratio is at least k, randomized k-server algorithms have the potential of reaching o(k)-competitive ratios. Prior to this work only few specific cases of this problem were solved. For arbitrary metric spaces, this goal may be approached by using probabilistic metric approximation techniques. This paper gives the first results in this direction, obtaining o(k)-competitive ratio for a natural class of metric spaces, including d-dimensional grids, and wide range of k.     

Dissipative localized States with shieldlike phase structure

A novel type of parametrically excited dissipative solitons is unveiled. It differs from the well-known solitons with constant phase by an intrinsically dynamical evolving shell-type phase front. Analytical and numerical characterizations are proposed, displaying quite a good agreement. In one spatial dimension, the system shows three types of stationary solitons with shell-like structure whereas in two spatial dimensions it displays only one, characterized by a π-phase jump far from the soliton position.     

Family constraining of iterative algorithms

In constraining iterative processes, the algorithmic operator of the iterative process is pre-multiplied by a constraining operator at each iterative step. This enables the constrained algorithm, besides solving the original problem, also to find a solution that incorporates some prior knowledge about the solution. This approach has been useful in image restoration and other image processing situations when a single constraining operator was used. In the field of image reconstruction from projections a priori information about the original image, such as smoothness or that it belongs to a certain closed convex set, may be used to improve the reconstruction quality. We study here constraining of iterative processes by a family of operators rather than by a single operator.     

Simultaneous Domination in Graphs

Let \({F_1, F_2, \ldots, F_k}\) be graphs with the same vertex set V. A subset \({S \subseteq V}\) is a simultaneous dominating set if for every i, 1 ≤ i ≤ k, every vertex of F _i not in S is adjacent to a vertex in S in F _i ; that is, the set S is simultaneously a dominating set in each graph F _i . The cardinality of a smallest such set is the simultaneous domination number. We present general upper bounds on the simultaneous domination number. We investigate bounds in special cases, including the cases when the factors, F _i , are r-regular or the disjoint union of copies of K _r . Further we study the case when each factor is a cycle.     

On the generalized Erdös-Szekeres Conjecture — a new upper bound

We prove the following result: For every two natural numbers n and q, n q + 2, there is a natural number E(n, q) satisfying the following:

1. (1) Let S be any set of points in the plane, no three on a line. If |S| E(n, q), then there exists a convex n-gon whose points belong to S, for which the number of points of S in its interior is 0 (mod q).

2. (2) For fixed q, E(n,q) 2^c(q)·n, c(q) is a constant depends on q only.

Part (1) was proved by Bialostocki et al. [2] and our proof is aimed to simplify the original proof. The proof of Part (2) is completely new and reduces the huge upper bound of [2] (a super-exponential bound) to an exponential upper bound.