Chalcogenide Nanocrystal Assembly: Controlling Heterogeneity And Modulating Heterointerfaces

This dissertation work is focused on developing methods to facilitate charge transport in heterostructured materials that comprise a nanoscale component. Multicomponent semiconductor materials were prepared by (1) spin coating of discrete nanomaterials onto porous silicon (pSi) or (2) self-assembly. Spin-coating of colloidal quantum dot (QD) PbS solutions was employed to create prototype PbS QD based radiation detection devices using porous silicon (pSi) as an n-type support and charge transport material. These devices were initially tested as a photodetector to ascertain the possibility of their use in high energy radiation detection. Short chain thiolate ligands (4-fluorothiophenolate) and anion passivation at the particle interface were evaluated to augment interparticle transport. However, the samples showed minimum interaction with the light source possibly due to poor infiltration into the pSi. The second project was also driven by the potential synergistic properties that can be achieved in multicomponent metal chalcogenide nanostructures, potentially useful in optoelectronic devices. Working with well-established methods for single component metal chalcogenide (MQ) particle gels this dissertation research sought to develop practical methods for co-gelation of different component particles with complimentary functionalities. By monitoring the kinetics of aggregation using time resolved dynamic light scattering and NMR spectroscopy the kinetics of aggregation of the two most common crystal structures for CdQ nanocrystals was studied and it was determined that the hexagonal (wurtzite) crystal structure aggregated faster than the cubic (zinc blende) crystal structure. For gel coupling of nanoparticles with differing Q (Q=S, Se and Te), once we accounted for the crystal structure effects, it was dtermined that the relative redox characteristics of Q govern the reaction rate. The oxidative sol-gel assembly routes were also employed to fabricate metal chalcogenide NC gels with different NC components with control over the degree of mixing. In order to control the degree of mixing, the factors that underscore sol-gel oxidative assembly were elucidated and the aggregation and gelation kinetics of metal chalcogenide QDs were monitored through time-resolved dynamic light scattering (TR-DLS), and nuclear magnetic resonance spectroscopy (NMR). Through these kinetic studies of the surface speciation of metal chalcogenides, control over heterogeneity in dual component CdSe-ZnS system, was achieved through adjustment of the capping ligand, the native crystal structure and the chalcogenide, thereby changing the relative rates of assembly for each component independently

Computer Aided Verification

This open access two-volume set LNCS 13371 and 13372 constitutes the refereed proceedings of the 34rd International Conference on Computer Aided Verification, CAV 2022, which was held in Haifa, Israel, in August 2022. The 40 full papers presented together with 9 tool papers and 2 case studies were carefully reviewed and selected from 209 submissions. The papers were organized in the following topical sections: Part I: Invited papers; formal methods for probabilistic programs; formal methods for neural networks; software Verification and model checking; hyperproperties and security; formal methods for hardware, cyber-physical, and hybrid systems. Part II: Probabilistic techniques; automata and logic; deductive verification and decision procedures; machine learning; synthesis and concurrency. This is an open access book

Embedded System Design

A unique feature of this open access textbook is to provide a comprehensive introduction to the fundamental knowledge in embedded systems, with applications in cyber-physical systems and the Internet of things. It starts with an introduction to the field and a survey of specification models and languages for embedded and cyber-physical systems. It provides a brief overview of hardware devices used for such systems and presents the essentials of system software for embedded systems, including real-time operating systems. The author also discusses evaluation and validation techniques for embedded systems and provides an overview of techniques for mapping applications to execution platforms, including multi-core platforms. Embedded systems have to operate under tight constraints and, hence, the book also contains a selected set of optimization techniques, including software optimization techniques. The book closes with a brief survey on testing. This fourth edition has been updated and revised to reflect new trends and technologies, such as the importance of cyber-physical systems (CPS) and the Internet of things (IoT), the evolution of single-core processors to multi-core processors, and the increased importance of energy efficiency and thermal issues

Embedded System Design

A unique feature of this open access textbook is to provide a comprehensive introduction to the fundamental knowledge in embedded systems, with applications in cyber-physical systems and the Internet of things. It starts with an introduction to the field and a survey of specification models and languages for embedded and cyber-physical systems. It provides a brief overview of hardware devices used for such systems and presents the essentials of system software for embedded systems, including real-time operating systems. The author also discusses evaluation and validation techniques for embedded systems and provides an overview of techniques for mapping applications to execution platforms, including multi-core platforms. Embedded systems have to operate under tight constraints and, hence, the book also contains a selected set of optimization techniques, including software optimization techniques. The book closes with a brief survey on testing. This fourth edition has been updated and revised to reflect new trends and technologies, such as the importance of cyber-physical systems (CPS) and the Internet of things (IoT), the evolution of single-core processors to multi-core processors, and the increased importance of energy efficiency and thermal issues

Nuclear Science Division annual report for the period October 1, 1987--September 30, 1988

Highlights of the low energy research program included the identification of new super-deformed bands in gadolinium and palladium isotopes using the HERA array. Other work at the 88-Inch Cyclotron involved studies of the fragmentation of light nuclei; the spectroscopy of nuclear far from stability and interesting new experiments on the properties of the heaviest elements. Two other programs deserve special mention, the new program in Nuclear Astrophysics and the spectroscopic studies being carried out at OASIS. This isotope separator is now in full operation at the SuperHILAC after many yeas of development. At the Bevalac, important new results were obtained on the properties of hot dense nuclear matter produced in central collisions of heavy ions. First measurements were made using the di-lepton spectrometer which provide the most direct access to the conditions at the earliest stage of the reaction. New results on pion interferometry have been obtained using the Janus spectrometer and surprises continue to be found in careful analysis of data from the Plastic Ball detector, most recently the identification of a new component of hydrodynamic flow. Also at the Bevalac the intermediate energy program continued to grow, studying the evolution of the reaction mechanism from incomplete fusion to the fireball regime, as did the spectroscopic studies using secondary radioactive beams. The third major component of the experimental program is the study of ultra-relativistic nuclear collisions using the CERN SPS. This year saw the completing of analysis of the first round of experiments with important results being obtained on general particle production, the space-time evolution of the system and strangeness production

Laboratory Directed Research and Development Annual Report - Fiscal Year 2000

The projects described in this report represent the Laboratory's investment in its future and are vital to maintaining the ability to develop creative solutions for the scientific and technical challenges faced by DOE and the nation. In accordance with DOE guidelines, the report provides, a) a director's statement, b) an overview of the laboratory's LDRD program, including PNNL's management process and a self-assessment of the program, c) a five-year project funding table, and d) project summaries for each LDRD project

Ahlfors circle maps and total reality: from Riemann to Rohlin

This is a prejudiced survey on the Ahlfors (extremal) function and the weaker {\it circle maps} (Garabedian-Schiffer's translation of "Kreisabbildung"), i.e. those (branched) maps effecting the conformal representation upon the disc of a {\it compact bordered Riemann surface}. The theory in question has some well-known intersection with real algebraic geometry, especially Klein's ortho-symmetric curves via the paradigm of {\it total reality}. This leads to a gallery of pictures quite pleasant to visit of which we have attempted to trace the simplest representatives. This drifted us toward some electrodynamic motions along real circuits of dividing curves perhaps reminiscent of Kepler's planetary motions along ellipses. The ultimate origin of circle maps is of course to be traced back to Riemann's Thesis 1851 as well as his 1857 Nachlass. Apart from an abrupt claim by Teichm\"uller 1941 that everything is to be found in Klein (what we failed to assess on printed evidence), the pivotal contribution belongs to Ahlfors 1950 supplying an existence-proof of circle maps, as well as an analysis of an allied function-theoretic extremal problem. Works by Yamada 1978--2001, Gouma 1998 and Coppens 2011 suggest sharper degree controls than available in Ahlfors' era. Accordingly, our partisan belief is that much remains to be clarified regarding the foundation and optimal control of Ahlfors circle maps. The game of sharp estimation may look narrow-minded "Absch\"atzungsmathematik" alike, yet the philosophical outcome is as usual to contemplate how conformal and algebraic geometry are fighting together for the soul of Riemann surfaces. A second part explores the connection with Hilbert's 16th as envisioned by Rohlin 1978.Comment: 675 pages, 199 figures; extended version of the former text (v.1) by including now Rohlin's theory (v.2

Physics division annual report 2005.

This report highlights the research performed in 2005 in the Physics Division of Argonne National Laboratory. The Division's programs include operation of ATLAS as a national user facility, nuclear structure and reaction research, nuclear theory, medium energy nuclear research and accelerator research and development. The mission of Nuclear Physics is to understand the origin, evolution and structure of baryonic matter in the universe--the matter that makes up stars, planets and human life itself. The Division's research focuses on innovative new ways to address this mission and 2005 was a year of great progress. One of the most exciting developments is the initiation of the Californium Rare Ion Breeder Upgrade, CARIBU. By combining a Cf-252 fission source, the gas catcher technology developed for rare isotope beams, a high-resolution isobar separator, and charge breeding ECR technology, CARIBU will make hundreds of new neutron-rich isotope beams available for research. The cover illustration shows the anticipated intensities of low-energy beams that become available for low-energy experiments and for injection into ATLAS for reacceleration. CARIBU will be completed in early 2009 and provide us with considerable experience in many of the technologies developed for a future high intensity exotic beam facility. Notable results in research at ATLAS include a measurement of the isomeric states in {sup 252}No that helps pin down the single particle structure expected for superheavy elements, and a new low-background measurement of {sup 16}N beta-decay to determine the {sup 12}C({alpha},{gamma}){sup 16}O reaction rate that is so important in astrophysical environments. Precise mass measurements shed new light on the unitarity of the quark weak-mixing matrix in the search for physics beyond the standard model. ATLAS operated for 4686 hours of research in FY2005 while achieving 95% efficiency of beam delivery for experiments. In Medium-Energy Physics, radium isotopes were trapped in an atom trap for the first time, a major milestone in an innovative search for the violation of time-reversal symmetry. New results from HERMES establish that strange quarks carry little of the spin of the proton and precise results have been obtained at JLAB on the changes in quark distributions in light nuclei. New theoretical results reveal that the nature of the surfaces of strange quark stars. Green's function Monte Carlo techniques have been extended to scattering problems and show great promise for the accurate calculation, from first principles, of important astrophysical reactions. Flame propagation in type 1A supernova has been simulated, a numerical process that requires considering length scales that vary by factors of eight to twelve orders of magnitude. Argonne continues to lead in the development and exploitation of the new technical concepts that will truly make an advanced exotic beam facility, in the words of NSAC, 'the world-leading facility for research in nuclear structure and nuclear astrophysics'. Our science and our technology continue to point the way to this major advance. It is a tremendously exciting time in science for these new capabilities hold the keys to unlocking important secrets of nature. The great progress that has been made in meeting the exciting intellectual challenges of modern nuclear physics reflects the talents and dedication of the Physics Division staff and the visitors, guests and students who bring so much to the research