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Abstract: We introduce an auxiliary coarse-grained routing layer (an expressway) on Chord, a DHT based structured peer-to-peer system. With the assumption that nodes in the system have different resource capacities such as storages and bandwidths, powerful (high connectivity and bandwidth) nodes can join the expressway to perform fast routing. We design the logical structure of an expressway overlay. We focus on the design and analysis of the logical structure of the expressway overlay that is parameterized by a characteristic called the forwarding power . Expressway nodes maintain more routing entries that can forward requests with a longer per hop distance than the underlying system. The expressway defers the “last mile” fine-grained routing to the underlying system. We also propose an event-based notification for membership and routing entry management on the expressway. Our initial experimental results of an expressway with a forwarding power of 4 show that the average logical path length of the system when over 20% of nodes join the expressway is about the same as when every node joins the expressway. The theoretical analysis shows that the logical routing path lengths of the system improve up to . The system requires messages to update all expressway routing entries when a node joins or leaves the system, where is the number of expressway nodes. [Copyright &y& Elsevier]

Describes a methodology for mid-frequency delta-I noise analysis of the power distribution network of a computer system. Information on the second power/ground distribution system; Presentation of a two-dimensional peak noise distributions; Provision of the module decoupling capacitors.

Presents a study which used low-barrier hydrogen bond (LBHB) complexes to investigate the relationship between calculated hydrogen bond strengths and calculated 1H nuclear magnetic resonance (NMR) chemical shifts. Characteristics of LBHB; Calculation of NMR chemical shifts; Results of the study.

Presents an experiment which was carried out in the gas phase on a series of enol--enolate complexes, focusing on short, strong hydrogen bonds. Location of the transition structure for proton transfer in the mesaconic system; Information on the emergency difference between short, strong and normal hydrogen bonds; Alternatives to short, strong hydrogen bonds in enzymatic catalysis.

Presents a theoretical investigation of phosphonamidates and sulfonamides as protease transition state isosteres. Methodology used; Information on two factors influencing the investigation; What has been attributed to the differences in the attitude of phosphonamidate and sulfonamide; Results and discussion of the study.

Focuses on the use of various calculations to study the effect of microsolvation on the strength of the a representative low-barrier hydrogen bond. Description of the hydrogen bond in ther gas phase; Action of the hydrogen bond when enol and enolate anion are microsolvated; Suggestion that the presence of interstitial water may not preclude the importance of low barrier hydrogen bonds in biological catalysts.

Reports on the study of comparative cumulene substituent effects of ketenes, allenes, diazomethanes, diazirines and cyclopropenes by ab initio molecular orbital calculations. Result of the comparison of charges calculated by the Mulliken, Natural Bond Orbital (NBO) and Bader methods.

Investigates various triamide conformations of For-Ala-Ala-NH2 by using ab initio calculations. X-ray crystallography; Analysis of type I' and type II' beta-turn conformations; Summary of all possible hairpin geometries of For-Ala-Ala-NH2.

Presents information on a study which investigates the relationship between pKa mismatch and hydrogen bond strength in a typical low-barrier hydrogen bond system, with reference to chemistry. Discussion on the link between pKa mismatch and hydrogen bond; Comparison of the smaller and larger differences in pKa values; Methodology used in the study; Results from the study.

Provides information on a study conducted on the characterization of low-barrier hydrogen bonds (LBHBs). Difference between short strong hydrogen bonds and LBHBs; Reference to previous studies of LBHBs; Methodology used to conduct study; Results of study.

Describes the characterization of low-barrier hydrogen bonds. Relationship between strength and geometry of short-strong hydrogen bonds; Formic acid-formate anion model system; Performance of ab initio and density functional theory investigation.

Characterizes the effects of microsolvation on the strength of low-barrier hydrogen bonds (LBHB). Interactions of formic acid molecules; Calculation of the interaction between water and formate; Geometries of LBHB; Relationship between the hydrogen bond distance and the calculated interaction energy.

Presents ab initio molecular orbital calculations of the structures and energies in the ring opening of cyclobutene-1,2-diones to form 1,3-butadiene-1,4-diones. Preference for twisted conformations; Ground state effects; Barriers for ring opening; Effects of substituents on the barriers and energy changes.

A process is described to produce single sheets of functionalized graphene through thermal exfoliation of graphite oxide. The process yields a wrinkled sheet structure resulting from reaction sites involved in oxidation and reduction processes. The topological features of single sheets, as measured by atomic force microscopy, closely match predictions of first-principles atomistic modeling. Although graphite oxide is an insulator, functionalized graphene produced by this method is electrically conducting. [ABSTRACT FROM AUTHOR]

Presents information relating to the chemical characteristics of the 6-oxocyclohexa-2,4-dienylideneketene. Measurement of the kinetics of the reactivity with water (H2O, methyl hydroxyl (MeOH), and ethyl2ammonia (Et2NH); Indication of ab initio molecular orbital calculations; Characterization of alpha-oxoketenes.

Kinetics and stereochemical studies have been carried out on the reactions of the Z and E isomers of O-methylbenzohydroximoyl halides [1Z and 1E, ArC(X)=NOCH3] with sodium methoxide in 9:1 DMSO-methanol. The reactions of methoxide ion with hydroximoyl fluorides (X = F) are stereospecific. The reaction with 1Z (X = F) gives only the Z substitution product (1Z, X =OCH3). The reaction of methoxide ion with 1E (X = F) is less selective, giving ca. 85% E substitution product. The Hammett ρ-values for the Z and E isomers (X = F) are +2.94 and +3.30, respectively. The element effects for 1Z (Ar = C6H5) are 2.21 (X -- Br):1.00 (X = C1):79.7 (X = F). The 1E element effects are (Ar = C6H5) 1.00 (X = Cl):18.3 (X = F) and (Ar = 4-CH3OC6H4) 1.97 (X = Br):1.00 (X = Cl):12.1 (X = F). The entropies of activation for these reactions are negative (for example, ΔS = -15 eu for 1Z and ΔS = -14 eu for 1E, Ar = 4-CH3OC6H4, X = F). These experimental observations are consistent with a mechanism proceeding through a tetrahedral intermediate. Ab initio calculations were carried out to help explain the stereospecificity of these reactions. These calculations indicate that the tetrahedral intermediate from the Z isomer undergoes rapid elimination to the Z substitution product before stereomutation can take place. These calculations also show that the lowest barrier for rotation around the carbon-nitrogen single bond in the tetrahedral intermediate derived from 1E leads to an intermediate that eliminates fluoride ion to give E product. [ABSTRACT FROM AUTHOR]

Analyzes the frequency dependencies of delta-I noise caused by variations of the on-chip switching activity. Variations in the noise source waveform; Description of decoupling capacitors; Definition of impedance as a function of frequency.

Examines the mechanisms of acid-catalyzed Z/E isomerization of imines. Use of glacial acetic acid and dioxane solutions containing HCL; Isomerization of hydroximoyl chlorides by the nucleophilic catalysis mechanism; Capability of hydroximate to isomerize by either mechanism.

Discusses the design of International Business Machines' (IBM) CMOS S/390 computer, focusing on the control of mid-frequency switching noise. Description of mid-frequency noise; What causes this noise; Details on the IBM CMOS S/390; Information on the design of system power distribution and modeling and verification of mid-frequency noise in this system.

Focuses on an experiment of the interconversion of cyclobutene-1, 2-diones and 1, 2-bisketnes for different combinations of substituents. Results of the investigation; Discussion on the investigation.