1,479 research outputs found
Study in optimization of microcircuit design Final report
Optimization of microcircuit reliabilit
Nuclear Condensations of Furan
In connection with studies on orientation of furan and the synthesis of beta-substituted furans, condensation reactions have been effected with diazomethane, aryl-diazonium compounds, diazoacetic ester and related types with furan and its derivatives. The condensations in some cases are preceded by 1,2- and 1,4- additions. It appears that the difficulty in preparing simple furan-diazonium compounds is due, in part, to the ready coupling reaction of the diazonium group with the furan nucleus
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Two-Dimensional Controlled Syntheses of Polypeptide Molecular Brushes via N-Carboxyanhydride Ring-Opening Polymerization and Ring-Opening Metathesis Polymerization.
Well-defined molecular brushes bearing polypeptides as side chains were prepared by a "grafting through" synthetic strategy with two-dimensional control over the brush molecular architectures. By integrating N-carboxyanhydride ring-opening polymerizations (NCA ROPs) and ring-opening metathesis polymerizations (ROMPs), desirable segment lengths of polypeptide side chains and polynorbornene brush backbones were independently constructed in controlled manners. The N2 flow accelerated NCA ROP was utilized to prepare polypeptide macromonomers with different lengths initiated from a norbornene-based primary amine, and those macromonomers were then polymerized via ROMP. It was found that a mixture of dichloromethane and an ionic liquid were required as the solvent system to allow for construction of molecular brush polymers having densely-grafted peptide chains emanating from a polynorbornene backbone, poly(norbornene-graft-poly(β-benzyl-l-aspartate)) (P(NB-g-PBLA)). Highly efficient postpolymerization modification was achieved by aminolysis of PBLA side chains for facile installment of functional moieties onto the molecular brushes
Distinguishing left- and right-handed molecules by two-step coherent pulses
Chiral molecules with broken parity symmetries can be modeled as quantum
systems with cyclic-transition structures. By using these novel properties, we
design two-step laser pulses to distinguish left- and right-handed molecules
from the enantiomers. After the applied pulse drivings, one kind chiral
molecules are trapped in coherent population trapping state, while the other
ones are pumped to the highest states for ionizations. Then, different chiral
molecules can be separated.Comment: 11 pages, 3 figures
Metabolic and Nutritional Aspects of Acute Renal Failure in Critically Ill Patients Requiring Continuous Renal Replacement Therapy
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141368/1/ncp0176.pd
Development of integrated thermionic circuits for high-temperature applications
Integrated thermionic circuits (ITC) capable of extended operation in ambient temperatures up to 500 C are studied. A set of practical design and performance equations is demonstrated. Experimental results are discussed in which both devices and simple circuits were successfully operated in 5000 C environments for extended periods. It is suggested that ITC's may become an important technology for high temperature instrumentation and control systems in geothermal and other high temperature environments
Sums of two squares and a power
We extend results of Jagy and Kaplansky and the present authors and show that
for all there are infinitely many positive integers , which cannot
be written as for positive integers , where for
a congruence condition is imposed on . These
examples are of interest as there is no congruence obstruction itself for the
representation of these . This way we provide a new family of
counterexamples to the Hasse principle or strong approximation.Comment: 6 pages, to appear in the memorial volume "From Arithmetic to
Zeta-Functions - Number Theory in Memory of Wolfgang Schwarz
Effect of aeroelastic-propulsive interactions on flight dynamics of a hypersonic vehicle
The desire to achieve orbit-on-demand access to space with rapid turn-around capability and aircraft-like processing operations has given rise to numerous hypersonic aerospace plane design concepts which would take off horizontally from a conventional runway and employ air-breathing scramjet propulsion systems for acceleration to orbital speeds. Most of these air-breathing hypersonic vehicle concepts incorporate an elongated fuselage forebody to act as the aerodynamic compression surface for a scramjet combustor module. This type of airframe-integrated scramjet propulsion system tends to be highly sensitive to inlet conditions and angle-of-attack perturbations. Furthermore, the basic configuration of the fuselage, with its elongated and tapered forebody, produces relatively low frequency elastic modes which will cause perturbations in the combustor inlet conditions due to the oscillation of the forebody compression surface. The flexibility of the forebody compression surface, together with sensitivity of scramjet propulsion systems to inlet conditions, creates the potential for an unprecedented form of aeroelastic-propulsive interaction in which deflections of the vehicle fuselage give rise to propulsion transients, producing force and moment variations that may adversely impact the longitudinal flight dynamics and/or excite the elastic modes. These propulsive force and moment variations may have an appreciable impact on the performance, guidance, and control of a hypersonic aerospace plane. The objectives of this research are to quantify the magnitudes of propulsive force and moment perturbations resulting from elastic deformation of a representative hypersonic vehicle, and to assess the potential impact of these perturbations on the vehicle's longitudinal flight dynamics
Some remarks on Vinogradov's mean value theorem and Tarry's problem
Let W(k, 2) denote the, least number s for which the system of equations has a solution with . We show that for large k one has W(k, 2)≦1/2k 2 (log k +loglog k + O (1)), and moreover that when K is large, one has W(k, 2)≦1/2k(k+1)+1 for at least one value k in the interval [ K, K 3/4+ε ]. We show also that the least s for which the expected asymptotic formula holds for the number of solutions of the above system of equations, inside a box, satisfies s ≦ k 2 (log k + O (loglog k ).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41627/1/605_2005_Article_BF01320189.pd
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