Dear pss readers, “This year's Nobel Prize in Physics recognizes the pioneering work of Professors Isamu Akasaki, Hiroshi Amano and Shuji Nakamura for the breakthrough developments in GaN materials and devices that enabled the field of solid state lighting. Blue LEDs have revolutionized display technology and enabled high efficiency white light sources.” said our Editorial Advisory Board member Jim Speck in response to our enthusiastic congratulations to his colleague at University of California, Santa Barbara. It was certainly an exceptional moment for a journal that has extensively documented GaN‐related research for decades. Isamu Akasaki and Hiroshi Amano, then both Meijo University and Nagoya University, published in pss on dislocations and stress in AlGaN/GaN thin films, e.g. [1, 2], Hiroshi Amano repeatedly acted as a guest editor [3–5], and all three laureates together have more than a 150 articles in pss and continue to publish on the topic. Obviously, though these contributions have gathered more than 1400 citations to date, not all are “breakthroughs”. Most are documenting continuous achievements in an important and highly specialized area. But together they witness the exceptional persistence required to master the growth of GaN to the degree of perfection that enabled blue LEDs. It is an example for the amount of patient, high‐level work that is necessary to turn a brilliant idea into a widespread invention, and pss is proud to accompany such progress along the way. Regarding today's promising trends in materials physics, we would like to showcase some of the special issues and topical sections that appeared in pss sister journals in 2014: “Oxide materials might form the basis for the next technological revolutions” according to J. M. Knaup, T. Frauenheim, P. Broqvist, and S. Ramanathan, the guest editors of the pss (RRL) Focus issue “Functional Oxides” [6]. These materials' enhanced complexity proposes both a greater challenge and greater benefits for future electronics and energy applications, and the 3 Reviews and 20 Letters offer computational and experimental perspectives on the current understanding. A topical section “Nanoscaled Magnetism and Applications”, guest‐edited by A. Zhukov, features contributions on magnetocaloric materials, spin relaxation, magnetization processes and magnetic nanostructures in pss (a) [7]. Another bustling topic in pss (a) are the recurring annual diamond and nanocarbon special issues, this time focused on “Advances on Diamond Surfaces and Devices” edited by B. Rezek, M. Nesládek, and K. Haenen [8], and kicked‐off by a Feature Article “Photoelectron emission from lithiated diamond” by K. M. O'Donnell, L. Ley, and others [9].
The logo of our journal assembled with blue GaN‐on‐Si LEDs (courtesy of Armin Dadgar, Otto‐von Guericke‐Universität, Magdeburg, Germany)相似文献
The Iwasawa manifold is uplifted to seven‐folds of either G2 holonomy or SU(3) structure, explicit new metrics for the same having been constructed in this work. We uplift the Iwasawa manifold to a G2 manifold through “size” deformation (of the Iwasawa metric), via Hitchin's Flow equations, showing also the impossibility of the uplift for “shape” and “size” deformations (of the Iwasawa metric). Using results of Dall'Agata and Prezas, Phys. Rev. D 69 , 066004 (2004) [arXiv:hep‐th/0311146] [1], we also uplift the Iwasawa manifold to a 7‐fold with SU(3) structure through “size” and “shape” deformations via generalisation of Hitchin's Flow equations. For seven‐folds with SU(3)‐structure, the result could be interpreted as M5‐branes wrapping two‐cycles embedded in the seven‐fold (as in [1]) ‐ a warped product of either a special hermitian six‐fold or a balanced six‐fold with the unit interval. There can be no uplift to seven‐folds of SU(3) structure involving non‐trivial “size” and “shape” deformations (of the Iwasawa metric) retaining the “standard complex structure” ‐ the uplift generically makes one move in the space of almost complex structures such that one is neither at the standard complex structure point nor at the “edge”. Using the results of Konopelchenko and Landolfi, J. Geom. Phys. 29 , 319 (1999) [arXiv:math.DG/9804144] [2], we show that given two “shape deformation” functions, and the dilaton, one can construct a Riemann surface obtained via Weierstraß representation for the conformal immersion of a surface in R l, for a suitable l, with the condition of having conformal immersion being a quadric in CP l‐1. 相似文献
Dear readers, authors and referees of physica status solidi, With the present issue and the start of the New Year following our 50th anniversary the editorial structure of pss undergoes some important formal changes. As already announced in the previous Editorial [1] twelve months ago, our former Editor‐in‐Chief Martin Stutzmann, Technische Universität München, has retired from the Editorial Board. This happens after 16 very successful years during which the journal has been brought back to prosperity. It is with deep gratitude to Martin for his strong vision, engagement, support and cooperation over one and a half decade that we meet this moment of changing duties. The fundamental transformation that the progress of electronic publishing brought to the business and the growth of pss to its current amount of output over the last years have resulted in an immense increase of workload for the editors, requiring practically full‐time dedication. Therefore, the role of an academic Editor‐in‐Chief will not be continued, transferring the central responsibility for pss to the hands of the Editors at the Wiley‐VCH office in Berlin and colleagues worldwide. We believe that this is a necessary modification to adapt to the changing publishing environment and habits, putting pss in a position to dynamically respond to ongoing developments. In fact, we currently observe the same policy change for other large journals in our publishing house, e.g. in polymer physics or quantum chemistry, not to mention successful Wiley‐VCH titles such as Advanced Materials or Angewandte Chemie which have been led by ‘in‐house’ Editorials for many years. Despite or even because of these present changes, close contacts of our editorial team to the scientific community will be ever more important for pss. This is why we strive to maintain and further develop a strong and active Board of the journal. Moreover, regardless of the differences in scope between pss (a) and (b), the trend of overlapping basic and applied research aspects in solid state physics has further manifested. Besides, our two other journals pss (RRL) and pss (c) cover the full spectrum of the field by definition. Therefore we have decided to create, from 2012, one joint Editorial Advisory Board for the entire pss family which will embrace many members of the previous separate Boards of the four journals (see ‘Issue Information’ online and inside front cover in the print edition, respectively). We are particularly pleased to welcome, at this moment, five new members to the Advisory Board: David A. Drabold , Ohio University, OH, USA; Sebastian T. B. Gönnenwein , Walther‐Meissner‐Institut and Technische Universität München, Garching, Germany; Nicholas Grandjean , École Polytechnique Fédérale de Lausanne, Switzerland; J. Marty Gregg , Queen’s University Belfast, UK; Ferdinand Scholz , Universität Ulm, Germany; and G. Jeffrey Snyder , California Institute of Technology, Pasadena, CA, USA. We will present them with photographs and short biographies in one of the forthcoming issues, and you should also look out for additional new Board members to join in the near future.
To control the plasma transport at the edge of a tokamak the outer flux surfaces can be artificially destroyed by applying a resonant helical magnetic field, as it is demonstrated at Pulsator [1],[2], [3], Tore Supra [4],[5] and proposed for TEXTOR-94 [6] in the concept of “ergodic divertors”. As a measure of the efficiency of the perturbation field e.g. the level of the field line diffusion coefficient DFL the width Δi of the magnetic islands and the related Chirikov parameter are of importance [7],[8],[9],[10]. For the planned Dynamic Ergodic Divertor (DED) at TEXTOR-94 where the perturbation coils are located at the high field side the standard expression for Δi using the Fourier components of the magnetic field perturbation [7] leads to results significantly different from field line tracing calculations [11]. The standard expression is commonly used in terms of the perturbation magnetic field δB [5],[7],[8],[9],[12],[13]. But when replacing the Fourier components of the perturbation vector potential by those of the magnetic field finite aspect ratio effects have been neglected so far. For present tokamaks with ? = r/R ? 0.3 this can lead to an error in the field line diffusion of one to two orders of magnitude. In this paper it is shown that taking into account the finite aspect ratio at this point leads to correct results compared to the highly precise field line tracing calculations by the Gourdon code. The island width then is recognized to depend significantly on the poloidal position of the perturbation field. This is in contrast to the standard expression. Also the role of the choice of the magnetic coordinate system is considered. 相似文献
We study the gauged sigma model and its mirror Landau‐Ginsburg model corresponding to type IIA on the Fermat degree‐24 hypersurface in WCP 4[1,1,2,8,12] (whose blow‐up gives the smooth CY3(3,243)) away from the orbifold singularities, and its orientifold by a freely‐acting antiholomorphic involution. We derive the Picard‐Fuchs equation obeyed by the period integral as defined in [1, 2], of the parent 𝒩 = 2 type IIA theory of [3]. We obtain the Meijer's basis of solutions to the equation in the large and small complex structure limits (on the mirror Landau‐Ginsburg side) of the abovementioned Calabi‐Yau, and make some remarks about the monodromy properties associated based on [4], at the same and another MATHEMATICAlly interesting point. Based on a recently shown 𝒩 = 1 four‐dimensional triality [6] between Heterotic on the self‐mirror Calabi‐Yau CY3(11,11), M theory on and F‐theory on an elliptically fibered CY4 with the base given by CP 1 × Enriques surface, we first give a heuristic argument that there can be no superpotential generated in the orientifold of of CY3(3,243), and then explicitly verify the same using mirror symmetry formulation of [2] for the abovementioned hypersurface away from its orbifold singularities. We then discuss briefly the sigma model and the mirror Landau‐Ginsburg model corresponding to the resolved Calabi‐Yau as well. 相似文献
The atmospheric‐pressure plasma needle is a promising source that can be used efficiently for different industrial applications. A radio frequency (RF) (13.56 MHz) generator was used to generate a He–O2/Ar mixture plasma. The ground‐state oxygen atomic density [O] was calculated as a function of discharge parameters by “actinometry”. The Ar‐I (2p1 → 1s2) line at 750 nm and the O‐I (3P → 3S) line at 844 nm were used to estimate the [O] atomic density. The rotational temperature T R of He–O2/Ar mixture was measured from the rotational levels of the “first negative system” (FNS) by using the “Boltzmann plot”. The effect of discharge parameters on the atomic oxygen density [O] and the gas temperature was monitored. These results show that [O] density increases with RF power and O2 concentration, but decreases with the gas flow rate. Whereas the gas temperature increases with increase in the input RF power, it decreases with increase in the gas flow rate and O2 concentration in the mixture. Since the [O] atomic density contributes to plasma‐based biomedical applications, the proposed optimum conditions for plasma‐based decontamination of heat‐sensitive materials in the present study are 0.6% oxygen, 500 sccm flow rate, and 26 W RF power. 相似文献
We complete the study [1] of smooth ℤ3‐quotients of complete intersection Calabi‐Yau threefolds by discussing the six new manifolds that admit free ℤ3 actions that were discovered in [2]. These manifolds were missed in [1] and complete the web of smooth ℤ3‐quotients in a nice way. We discuss the transitions between these manifolds and include also the other manifolds of the web. This leads to the conclusion that the web of ℤ3‐free quotients of complete intersection Calabi‐Yau threefolds is connected by conifold transitions. 相似文献