Publications

More than 200 papers, two special issues (Journal of Circuits, Systems, and Computers, March, June, 1993, and IEEE Trans. on Circuits and Systems, vol. 40, no. 10, October, 1993), an International Workshop on Chua’s Circuit: chaotic phenomena and applica tions at NOLTA’93, and a book (edited by R.N. Madan, World Scientific, 1993) on Chua’s circuit have been published since its inception a decade ago. This review paper attempts to present an overview of these timely publications, almost all within the last six months, and to identify four milestones of this very active research area. An important milestone is the recent fabrication of a monolithic Chua’s circuit. The robustness of this IC chip demonstrates that an array of Chua’s circuits can also be fabricated into a monolithic chip, thereby opening the floodgate to many unconventional applications in information technology, synergetics, and even music. The second milestone is the recent global unfolding of Chua’s circuit, obtained by adding a linear resistor in series with the inductor to obtain a canonical Chua’s circuit— now generally referred to as Chua’s oscillator. This circuit is most significant because it is structurally the simplest (it contains only 6 circuit elements) but dynamically the most complex among all nonlinear circuits and systems described by a 21-parameter family of continuous odd-symmetric piecewise-linear vector fields. The third milestone is the recent discovery of several important new phenomena in Chua’s circuits, e.g., stochastic resonance, chaos-chaos type intermittency, 1/f noise spectrum, etc. These new phenomena could have far-reaching theoretical and practical significance. The fourth milestone is the theoretical and experimental demonstration that Chua’s circuit can be easily controlled from a chaotic regime to a prescribed periodic or constant orbit, or it can be synchronized with 2 or more identical Chua’s circuits, operating in an oscillatory, or a chaotic regime. These recent breakthroughs have ushered in a new era where chaos is deliberately created and exploited for unconventional applications, e.g. secure communication.

ADVERTISEMENT RETURN TO ISSUEPREVCommentNEXTThe Changing Landscape of Physical Chemistry at the Beginning of the 21st CenturyG. A. Somorjai and R. D. LevineView Author Information Department of Chemistry and Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720-1460, and Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095. Cite this: J. Phys. Chem. B 2005, 109, 19, 9853–9854Publication Date (Web):April 27, 2005Publication History Received10 December 2004Published online27 April 2005Published inissue 1 May 2005https://pubs.acs.org/doi/10.1021/jp040754qhttps://doi.org/10.1021/jp040754qarticle-commentaryACS PublicationsCopyright © 2005 American Chemical Society. This publication is available under these Terms of Use. Request reuse permissions This publication is free to access through this site. Learn MoreArticle Views560Altmetric-Citations2LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail PDF (13 KB) Get e-AlertscloseSUBJECTS:Catalysts,Molecular structure,Molecules,Physical chemistry,Selectivity Get e-Alerts

The concept of self-assembled dendrimers is explored for the creation of discrete nanoparticle assemblies. Hybridization of branched DNA trimers and nanoparticle-DNA conjugates results in the synthesis of nanoparticle trimer and tetramer complexes. Multiple tetramer architectures are investigated, utilizing Au-DNA conjugates with varying secondary structural motifs. Hybridization products are analyzed by gel electrophoresis, and discrete bands are observed corresponding to structures with increasing numbers of hybridization events. Samples extracted from each band are analyzed by transmission electron microscopy, and statistics compiled from micrographs are used to compare assembly characteristics for each architecture. Asymmetric structures are also produced in which both 5 and 10 nm Au particles are assembled on branched scaffolds.

It has recently been proposed that subsurface oxygen is crucial for the adsorption and subsequent electroreduction of CO₂ on copper. Using density functional theory, we have studied the stability and diffusion of subsurface oxygen in single crystals of copper exposing (111) and (100) facets. Oxygen is at least 1.5 eV more stable on the surface than beneath it for both crystal orientations; interstitial sites are too small to accommodate oxygen. The rate of atomic oxygen diffusion from one layer below a Cu(111) surface to the surface is 5 × 10³ s^-1. Oxygen can survive longer in deeper layers, but it does not promote CO₂ adsorption there. Diffusion of subsurface oxygen is easier to the less-dense Cu(100) surface, even from lower layers (rate ≈ 1 × 10⁷ s^-1). Once the applied voltage and dispersion forces are properly modeled, we find that subsurface oxygen is unnecessary for CO₂ adsorption on copper.

Antisite defects, disorder between Li and other cations, are often observed in Li storage compounds synthesized at elevated temperature. In battery materials that have distinct one-dimensional (1-D) Li diffusion channels, preventing antisite formation is considered a good way to obtain desirable electrochemical properties by avoiding channel blockage, which can significantly disrupt Li transport. Thus, it is of critical importance to understand how the antisite modulates the overall Li kinetics in cathode materials. In this work, we investigate lithium manganese borate (LiMnBO 3 ) as a model system in which Li diffuses along the c -axis of its monoclinic lattice. Although it has high theoretical capacity of 222 mAh/g, antisite defects limit the achievable capacity to half of its theoretical value. Our approach to address this limitation is to partially substitute Mn with Fe, which not only leads to immediate improvement in electrochemical properties but also increases the antisite defect concentration. By using ab initio computation and analyzing experimental results, we find that different antisite configurations can affect Li intercalation in different ways and, counter to intuition, channel blockage by the antisite defects is not always detrimental in 1-D materials. At certain conditions, Li migration occurs by channel crossover to detour the channel-blocking defect, and the basic diffusion mechanism is modified from 1-D to 3-D conduction, thereby improving kinetics. This is a refreshing perspective on antisite issues in the 1-D materials. Our model may provide hints to understand and enhance the electrochemical performance of other 1-D materials that suffer from kinetic limitations due to antisite defect through engineering of defect chemistry.