There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

인공고관절의 세라믹 볼 헤드의 기계적 안정성 평가를 위한 3 차원 유한요소 해석

The authors review the present status of self-consistent mean-field (SCMF) models for describing nuclear structure and low-energy dynamics. These models are presented as effective energy-density functionals. The three most widely used variants of SCMF's based on a Skyrme energy functional, a Gogny force, and a relativistic mean-field Lagrangian are considered side by side. The crucial role of the treatment of pairing correlations is pointed out in each case. The authors discuss other related nuclear structure models and present several extensions beyond the mean-field model which are currently used. Phenomenological adjustment of the model parameters is discussed in detail. The performance quality of the SCMF model is demonstrated for a broad range of typical applications.

Self-consistent mean-field models for nuclear structure

The structural properties of free nanoclusters are reviewed. Special attention is paid to the interplay of energetic, thermodynamic, and kinetic factors in the explanation of cluster structures that are actually observed in experiments. The review starts with a brief summary of the experimental methods for the production of free nanoclusters and then considers theoretical and simulation issues, always discussed in close connection with the experimental results. The energetic properties are treated first, along with methods for modeling elementary constituent interactions and for global optimization on the cluster potential-energy surface. After that, a section on cluster thermodynamics follows. The discussion includes the analysis of solid-solid structural transitions and of melting, with its size dependence. The last section is devoted to the growth kinetics of free nanoclusters and treats the growth of isolated clusters and their coalescence. Several specific systems are analyzed.

/pdf/structural-properties-of-nanoclusters-energetic-56vj4t3ucw.pdf

Structural properties of nanoclusters: Energetic, thermodynamic, and kinetic effects

We investigate, from a theoretical perspective, photo-emission of electrons induced by ultra-short infrared pulses covering only a few photon cycles. In particular, we investigate the impact of the Carrier-Envelope Phase (CEP) of the laser pulse which plays an increasingly large role for decreasing pulse length. As key observable we look at the asymmetry of the angular distribution as function of kinetic energy of the emitted electrons. The focus of the present study lies on the system dependence of the reaction. To this end, we study two very different systems in comparison, an Ar atom and the Na9+ cluster. The study employs a fully quantum-mechanical description of electron dynamics at the level of Time-Dependent Density Functional Theory (TDDFT). We find a sensitive dependence on the system which can be related to the different spectral response properties. Results can be understood from an interplay of the ponderomotive motion driven by the external photon field and dynamical polarization of the system.

The impact of the carrier envelope phase -- dependence on system and laser parameters

Using a combined quantum-mechanical--classical method, we study the collisions of small Na clusters with large Ar clusters as a model for cluster deposition. We work out basic mechanisms by systematic variation of the collision energy, system sizes, and orientations. The soft Ar material is found to serve as an extremely efficient shock absorber. The collisional energy is quickly transferred at first impact, and the Na clusters are always captured by the Ar surface. The distribution of the collision energy into the Ar system proceeds very fast at the velocity of sound. The relaxation of shapes goes at a slower pace using times of several picoseconds. It produces a substantial rearrangement of the Ar system, while the Na cluster remains rather robust.

Shape dynamics during deposit of simple metal clusters on rare-gas matrices

We discuss the response of clusters subject to intense laser fields in the framework of a time dependent density functional approach which allows a fully non adiabatic treatment of both electronic and ionic degrees of freedom. Most results have been obtained for simple metal clusters. We discuss in this case the importance of the plasmon resonance in the electronic response. We also consider the impact of ionic motion on the ionization of these metal clusters. We show in particular that for long enough pulses, ionic expansion can drive the system into resonance with the electronic plasmon resonance, which leads to a strongly enhanced ionization. We finally consider the case of hydrogen clusters, in relation to recent experiments on fusion from irradiated deuterium clusters. We analyze the response of small hydrogen clusters to moderately intense lasers with intensities up to typically a few 10 15 W cm -2 . Ionic degrees of freedom seem to be here even more important.

Clusters in intense laser pulses

Instabilities in the nonlinear relativistic mean-field model

We present a detailed study of the deposition of small sodium clusters on a NaCl surface. To that end, we use a microscopic model based on the Time-Dependent Local Density Approximation (TDLDA) for electrons, coupled to classical Molecular Dynamics (MD) for ions. We discuss in particular the deposition mechanism for different initial cluster velocities and demonstrate that extremely slow velocities are necessary to ensure a cluster deposition without damaging the original cluster.

Paul-Gerhard Reinhard

Papers

The impact of the carrier envelope phase -- dependence on system and laser parameters

Shape dynamics during deposit of simple metal clusters on rare-gas matrices

Clusters in intense laser pulses

Instabilities in the nonlinear relativistic mean-field model

Velocity dependence of metal cluster deposition on an insulating surface