X-ray Observation and Analysis of The Composite Supernova Remnant G327.1-1.1

Based on the data from the observation of the SNR G327.1-1.1 by ASCA and ROSAT, we find that G327.1-1.1 is a composite remnant with both a nonthermal emission component and a diffuse thermal emission component. The nonthermal component is well fitted by a power-law model with photon index about 2.2. This component is attributed to the emission from the synchrotron nebula powered by an undiscovered central pulsar. The thermal component has a temperature of about 0.4 keV. We attribute it to the emission from the shock-heat swept-up ISM. Its age, explosion energy and density of ambient medium are derived from the observed thermal component. Some charactistics about the synchrotron nebula are also derived. We search for the pulsed signal, but has not found it. The soft X-ray(0.4 - 2 keV) and hard X-ray(2 - 10 keV) images are different, but they both elongate in the SE-NW direction. And this X-ray SE-NW elongation is in positional coincidence with the radio ridge in MOST 843MHz radio map. We present a possibility that the X-ray nonthermal emission mainly come from the trail produced by a quickly moving undiscoverd pulsar, and the long radio ridge is formed when the pulsar is moving out of the boundary of the plerionic structure.Comment: 20 pages, 4 Postscript figures, aasms4.sty and psfig.sty, to be published in Astrophysical Journal, January 20, 1999, Vol. 51

An analysis of the X-ray emission from the supernova remnant 3C397

The ASCA SIS and the ROSAT PSPC spectral data of the SNR 3C397 are analysed with a two-component non-equilibrium ionization model. Besides, the ASCA SIS0 and SIS1 spectra are also fitted simultaneously in an equilibrium case. The resulting values of the hydrogen column density yield a distance of \sim8\kpc to 3C397. It is found that the hard X-ray emission, containing S and Fe K$\alpha$ lines, arises primarily from the hot component, while most of the soft emission, composed mainly of Mg, Si, Fe L lines, and continuum, is produced by the cool component. The emission measures suggest that the remnant evolves in a cloudy medium and imply that the supernova progenitor might not be a massive early-type star. The cool component is approaching ionization equilibrium. The ages estimated from the ionization parameters and dynamics are all much greater than the previous determination. We restore the X-ray maps using the ASCA SIS data and compare them with the ROSAT HRI and the NRAO VLA Sky Survey (NVSS) 20 cm maps. The morphology with two bright concentrations suggests a bipolar remnant encountering a denser medium in the west.Comment: 20 pages, aasms4.sty, 3 figures To appear in ApJ (1999

Is it possible to formulate least action principle for dissipative systems?

A longstanding open question in classical mechanics is to formulate the least action principle for dissipative systems. In this work, we give a general formulation of this principle by considering a whole conservative system including the damped moving body and its environment receiving the dissipated energy. This composite system has the conservative Hamiltonian $H=K_1+V_1+H_2$ where $K_1$ is the kinetic energy of the moving body, $V_1$ its potential energy and $H_2$ the energy of the environment. The Lagrangian can be derived by using the usual Legendre transformation $L=2K_1+2K_2-H$ where $K_2$ is the total kinetic energy of the environment. An equivalent expression of this Lagrangian is $L=K_1-V_1-E_d$ where $E_d$ is the energy dissipated by the friction from the moving body into the environment from the beginning of the motion. The usual variation calculus of least action leads to the correct equation of the damped motion. We also show that this general formulation is a natural consequence of the virtual work principle.Comment: 11 pages, no figur

Evidence for coupling between collective state and phonons in two-dimensional charge-density-wave systems

We report on a Raman scattering investigation of the charge-density-wave (CDW), quasi two-dimensional rare-earth tri-tellurides $R$Te$_3$ ($R$= La, Ce, Pr, Nd, Sm, Gd and Dy) at ambient pressure, and of LaTe$_3$ and CeTe$_3$ under externally applied pressure. The observed phonon peaks can be ascribed to the Raman active modes for both the undistorted as well as the distorted lattice in the CDW state by means of a first principles calculation. The latter also predicts the Kohn anomaly in the phonon dispersion, driving the CDW transition. The integrated intensity of the two most prominent modes scales as a characteristic power of the CDW-gap amplitude upon compressing the lattice, which provides clear evidence for the tight coupling between the CDW condensate and the vibrational modes

Fermi Surface reconstruction in the CDW state of CeTe3 observed by photoemission

CeTe3 is a layered compound where an incommensurate Charge Density Wave (CDW) opens a large gap (400 meV) in optimally nested regions of the Fermi Surface (FS), whereas other sections with poorer nesting remain ungapped. Through Angle-Resolved Photoemission, we identify bands backfolded according to the CDW periodicity. They define FS pockets formed by the intersection of the original FS and its CDW replica. Such pockets illustrate very directly the role of nesting in the CDW formation but they could not be detected so far in a CDW system. We address the reasons for the weak intensity of the folded bands, by comparing different foldings coexisting in CeTe3

Informal Action—Adjudication—Rule Making: Some Recent Developments in Federal Administrative Law

Direct energy consumption of ICT hardware is only “half the story.” In order to get the “whole story,” energy consumption during the entire life cycle has to be taken into account. This chapter is a first step toward a more comprehensive picture, showing the “grey energy” (i.e., the overall energy requirements) as well as the releases (into air, water, and soil) during the entire life cycle of exemplary ICT hardware devices by applying the life cycle assessment method. The examples calculated show that a focus on direct energy consumption alone fails to take account of relevant parts of the total energy consumption of ICT hardware as well as the relevance of the production phase. As a general tendency, the production phase is more and more important the smaller (and the more energy-efficient) the devices are. When in use, a tablet computer is much more energy-efficient than a desktop computer system with its various components, so its production phase has a much greater relative importance. Accordingly, the impacts due to data transfer when using Internet services are also increasingly relevant the smaller the end-user device is, reaching up to more than 90 % of the overall impact when using a tablet computer.QC 20140825</p

Quasinormal Modes in three-dimensional time-dependent Anti-de Sitter spacetime

The massless scalar wave propagation in the time-dependent BTZ black hole background has been studied. It is shown that in the quasi-normal ringing both the decay and oscillation time-scales are modified in the time-dependent background.Comment: 8 pages and 7 figure

Thermodynamic optimization of steady-flow industrial chemical processes

© 2018, The Author(s). Industrial steady-flow chemical processes are generally organised as a sequence of individually optimised operations. However, this may not achieve overall optimization since material (as recycle), heat and work transfers overall may not be well balanced. We introduce the idea of a preliminary overall thermodynamic balance to produce a reversible process, with the objective of minimising, for both economic and environmental reasons, the quality and quantity of energy used. This balance may later require adjustment to account for the realities of available materials and equipment. For this purpose, we introduce (i) a Carnot temperature, TCarnot, by which a Carnot machine (an engine which can operate as either a heat pump or a turbine) can supply the required heat at the correct temperature for a process to operate reversibly, that is with least energy, and (ii) the GH Diagram on which Carnot temperature-based processes are plotted in ?G–?H space. We demonstrate the utility of this analysis by simple application to the Haber–Bosch process for ammonia synthesis and by a sequence of operations for the synthesis of methanol. We also briefly introduce the state function exergy, which uses the natural environment as the reference base for energy in place of pure elements under standard conditions

Global organization of metabolic fluxes in the bacterium, Escherichia coli

Cellular metabolism, the integrated interconversion of thousands of metabolic substrates through enzyme-catalyzed biochemical reactions, is the most investigated complex intercellular web of molecular interactions. While the topological organization of individual reactions into metabolic networks is increasingly well understood, the principles governing their global functional utilization under different growth conditions pose many open questions. We implement a flux balance analysis of the E. coli MG1655 metabolism, finding that the network utilization is highly uneven: while most metabolic reactions have small fluxes, the metabolism's activity is dominated by several reactions with very high fluxes. E. coli responds to changes in growth conditions by reorganizing the rates of selected fluxes predominantly within this high flux backbone. The identified behavior likely represents a universal feature of metabolic activity in all cells, with potential implications to metabolic engineering.Comment: 15 pages 4 figure