Using the random phase approximation, we have calculated the total and directional components of the mean excitation energy for stopping (I0) and the stopping anisotropy (
) as well as the first moment (I1) of the dipole oscillator strength distribution for 20 small molecules and molecular ions containing 6 to 30 electrons. We find that for excitations polarized orthogonal (perpendicular) and parallel to the molecular high symmetry axis I0O > I0P for all linear molecules, while I1O < I1P for all molecules other than HF. We note that the Bloch rule holds only for small, compact molecules, and that the Bragg rule should not be used to determine the mean excitation energies of the molecules that we consider here. The stopping anisotropy is positive for all but the C3v molecules, and is largest for the linear, rod-shaped molecules. 相似文献
Tire and bitumen particle concentrations are determined in aerosol and soil samples. They each constitute about 5 wt-% of the total suspended particulate matter (TSP) in inner city air, collected with a Berner low pressure impactor, 5 m from a road. The particle size distribution shows that 92% of the mass of airborne particulate tire debris have aerodynamic diameters smaller than 1 µm. The mean aerodynamic diameter is about 1 µm for the bitumen particles. This size range enables the possibility for far range transport and inhalation by humans. Soil concentrations in the vicinity of a highway indicate an approximate exponential decrease with increasing distance from the road. Constant values are reached after about 5 m for the tire particles and 10 m for the bitumen particles. Concentrations in soil that has not been touched for at least 30 years show a decrease in tire concentration by a factor of 30 when moving from the top soil to a depth of 3 cm. The bitumen concentration is approximately constant to a depth of 10 cm. 相似文献
Substantial inertia is frequently experienced in the initiation phase of a project, and in order to overcome that inertia, attention must be paid to four critical factors: time and energy, willpower, opportunity and the project's ‘basic concept’. These four factors are explained, and their application in different countries is discussed with reference to Hofstede's cultural dimensions. 相似文献
Zusammenfassung Es wurden Modellversuche zur Bildung von N-Carboxymethyllysin (CML) an erhitzten Wurstbrätproben mit unterschiedlichen Zusätzen durchgeführt. In der Reaktion des Lysins mit Ascorbat wird offensichtlich mehr CML gebildet als in der Reaktion des Lysins mit Glucose. Ein Zusatz von Ascorbat in handelsüblicher Konzentration erhöhte den CML-Gehalt im Wurstbrät auf 35 mg, der von Glucose in sogar höherer Konzentration dagegen nur auf 23 mg, gegenüber 17 mg CML/kg Rohprotein in der Kontrollprobe. Ein Zusatz von Diphosphat in handelsüblicher Konzentration neben Glucose bewirkte eine signifikante Steigerung der CML-Gehalte von 23 mg auf 30 mg CML/kg Rohprotein. Die gesetzlich zugelassene Höchstmenge an Nitrit übte dagegen keinen Einfluß auf die CML-Bildung aus (21 mg CML/kg Rohprotein). Die Absolutwerte sind generell gering, verglichen mit CML-Gehalten in anderen Lebensmitteln wie Milchprodukten.
Model experiments with sausage meat on the formation of N-carboxymethyllysine
In model experiments the influence of ingredients normally used for sausage production to a meat homogenate on the formation of N-carboxymethyllysine (CML) was investigated. The formation of CML is obviously more promoted from the reaction of ascorbate with lysine than from that of glucose with lysine. The addition of ascorbate in a practical concentration yielded 35 mg, the addition of glucose only 23 mg compared to 17 mg CML/kg protein in the control sample. The addition of diphosphate in a practical concentration besides glucose significantly increased the CML values from 23 mg to 30 mg CML/kg protein. On the other hand, nitrite did not enhance the formation of CML (21 mg/kg protein) in the sausage when used in concentrations usually applied in meat processing. Generally the values found in the meat products are quite low compared to data in other foods like milk products.
Selective eta-expansion is a powerful binding-time improvement,i.e., a source-program modification that makes a partial evaluator yield better results. But like most binding-time improvements, the exact problem it solves and the reason why have not been formalized and are only understood by few.In this paper, we describe the problem and the effect of eta-redexes in terms of monovariant binding-time propagation: eta-redexes preserve the static data flow of a source program by interfacingstatic higher-order values in dynamic contexts anddynamic higher-order values in static contexts. They contribute to twodistinct binding-time improvements.We present two extensions of Gomard's monovariant binding-time analysis for the pure -calculus. Our extensions annotateand eta-expand -terms. The first one eta-expands static higher-order values in dynamic contexts. The second also eta-expands dynamic higher-order values in static contexts.As a significant application, we show that our first binding-time analysis suffices to reformulate the traditional formulation of a CPS transformation into a modern one-pass CPS transformer. This binding-time improvement is known, but it is still left unexplained in contemporary literature,e.g., about cps-based partial evaluation.We also outline the counterpart of eta-expansion for partially static data structures. 相似文献
The movingA-B interface emits second sound which extracts the latent heat from the transition region. The amplitude is calculated for all interface velocities
. A pronounced maximum is found if
is close to the second sound velocity. 相似文献
In this paper, we introduce a fast and consistent smoothed particle hydrodynamics (SPH) technique which is suitable for convection–diffusion simulations of incompressible fluids. We apply our temporal blending technique to reduce the number of particles in the simulation while smoothly changing quantity fields. Our approach greatly reduces the error introduced in the pressure term when changing particle configurations. Compared to other methods, this enables larger integration time‐steps in the transition phase. Our implementation is fully GPU‐based to take advantage of the parallel nature of particle simulations.相似文献
Tutte proved that every 3-vertex-connected graph G on more than 4 vertices has a contractible edge. Barnette and Grünbaum proved the existence of a removable edge in the same setting. We show that the sequence of contractions and the sequence of removals from G to K4 can be computed in O(|V|2) time by extending Barnette’s and Grünbaum’s theorem. As an application, we derive a certificate for the 3-vertex-connectivity of graphs that can be easily computed and verified. 相似文献
Model synchronization, i.e., the task of restoring consistency between two interrelated models after a model change, is a challenging task. Triple graph grammars (TGGs) specify model consistency by means of rules that describe how to create consistent pairs of models. These rules can be used to automatically derive further rules, which describe how to propagate changes from one model to the other or how to change one model in such a way that propagation is guaranteed to be possible. Restricting model synchronization to these derived rules, however, may lead to unnecessary deletion and recreation of model elements during change propagation. This is inefficient and may cause unnecessary information loss, i.e., when deleted elements contain information that is not represented in the second model, this information cannot be recovered easily. Short-cut rules have recently been developed to avoid unnecessary information loss by reusing existing model elements. In this paper, we show how to automatically derive (short-cut) repair rules from short-cut rules to propagate changes such that information loss is avoided and model synchronization is accelerated. The key ingredients of our rule-based model synchronization process are these repair rules and an incremental pattern matcher informing about suitable applications of them. We prove the termination and the correctness of this synchronization process and discuss its completeness. As a proof of concept, we have implemented this synchronization process in eMoflon, a state-of-the-art model transformation tool with inherent support of bidirectionality. Our evaluation shows that repair processes based on (short-cut) repair rules have considerably decreased information loss and improved performance compared to former model synchronization processes based on TGGs.