Interplay of coupling and superradiant emmision in the optical response of a double quantum dot

We study theoretically the optical response of a double quantum dot structure to an ultrafast optical excitation. We show that the interplay of a specific type of coupling between the dots and their collective interaction with the radiative environment leads to very characteristic features in the time-resolved luminescence as well as in the absorption spectrum of the system. For a sufficiently strong coupling, these effects survive even if the transition energy mismatch between the two dots exceeds by far the emission linewidth.Comment: 9 pages, 5 figures; considerably extended versio

A new zooarchaeological application for geometric morphometric methods: Distinguishing Ovis aries morphotypes to address connectivity and mobility of prehistoric Central Asian pastoralists.

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Geometric morphometric methods (GMM), which were developed to characterize the shape and size of biological organisms, have been applied within zooarchaeology over the past decade to address animal domestication processes and to refine morphological criteria to differentiate between taxa. However, there has been limited utilization of these methods to discriminate between populations of the same taxa to challenge and refine other key archaeological issues, such as migration and connectivity in prehistory. Presented here is a novel application of a three-dimensional landmark based geometric morphometric approach to address the nature of long distance trade and connectivity on the prehistoric Silk Road. The similarity of Bronze and Iron Age archaeological cultures along this steppe route has encouraged characterisations of these people as nomads, with highly mobile, integrated, and connected human and animal populations. However, the interconnectedness of domestic animal populations, in particular sheep (Ovis aries), the foundation of this prehistoric pastoral economy, has never been examined. This study utilized geometric morphometric methods to quantify geometric morphometric variance of O. aries astragali between three geographically disparate settlement sites within a single Final Bronze age cultural and chronological context. Significant differences between morphotypes revealed that protracted mobility patterns were unlikely and that while animal exchange may have occurred, it was not pervasive enough to produce a uniform sheep morphotype across central and southeastern Kazakhstan. The result of this new application of geometric morphometric methods challenges models of uniform and undifferentiated long distance mobility and economic connectivity between the peoples of the Silk Road.Fulbright scholarshipFrances Mary Hazen fellowshi

Admittance of CdS nanowires embedded in porous alumina template

CdSnanowires of 10nm diameter, electrodeposited in porous alumina films, had shown a conductance bistability in the past [Appl. Phys. Lett.76, 460 (2000)]. The conductance has a high (ON) and a low (OFF) state. In the ON state, different sets of nanowires display qualitatively different relation between the conductance and capacitance. We propose a model to explain this anomalous behavior. Based on this model, we predict that the inelastic mean free path of electrons in the nanowires is 3–3.5nm at room temperature. This short mean free path may be a consequence of acoustic phonon confinement

Non-perturbative vacuum-polarization effects in proton-laser collisions

In the collision of a high-energy proton beam and a strong laser field, merging of the laser photons can occur due to the polarization of vacuum. The probability of photon merging is calculated by accounting exactly for the laser field and presents a highly non-perturbative dependence on the laser intensity and frequency. It is shown that the non-perturbative vacuum-polarization effects can be experimentally measured by combining the next-generation of table-top petawatt lasers with presently available proton accelerators.Comment: 5 pages, 2 figure

Особенности изготовления отливок из алюминиевых сплавов по выжигаемым аддитивным FDM-моделям

This article describes the results of a study aimed at improving production technology of experimental castings from aluminum alloys by investment casting using models produced by 3D printing. The consumable models were produced using fused deposition modeling (FDM). Biodegradable polylactide (PLA) was used as a material for the models. In order to decrease the surface roughness of consumable PLA  model.  chemical  post-treatment  by  dichloromethane  needs  to  be  performed.  After  immersion  of  the  model  into the solvent for 10s, its surface becomes smooth and glossy. Three-point static bending tests of PLA plates demonstrated a mechanical strength of average ~45.1 MPa. A thermomechanical analysis of polylactide demonstrated that in the course of heating of ceramic shell in excess of 150 °C, the polylactide model begins to expand intensively by exerting significant pressure on the ceramic shell. In order to decrease stress during the removal of polylactide model from ceramic mold, the heating time in the range of 150–300 °C needs to be heated to a maximum. The use of hollow consumable casting models with a cellular structure not higher than 30 % is also sensible. The stresses on the shell will not exceed its strength. Characteristic  temperature  properties  of  PLA  plastic  thermal  destruction  were detected using thermogravimetric analysis. Polylactide was established to completely burn out upon  heating  to 500  °C  leaving  no ash residue. Analysis of the results identified the burning modes of polylactide models from ceramic molds. Using a Picaso 3D Designer printer (Russia), the PLA models were printed used for production of experimental castings from aluminum alloys. It was revealed that the surface roughness (Ra) of a casting produced using a consumable model treated by dichloromethane decreases by 81.75 %: from 13.7 to 2.5 μm.Приведены результаты исследований, направленные на совершенствование литейной технологии получения опытно-экспериментальных отливок из алюминиевых сплавов методом литья по выжигаемым моделям, изготовленным с применением 3D-печати. Для создания выжигаемых моделей использовали метод осаждения расплавленной нити (FDM – fused deposition modeling), а в качестве материала моделей был выбран биоразлагаемый материал – полилактид (PLA – polylactide). Установлено, что для уменьшения  шероховатости  выжигаемой  PLA-модели  необходимо  проводить  химическую  постобработку ее поверхности дихлорметаном. В результате окунания модели в растворитель на 10 с она приобретает гладкую и глянцевую поверхность. Испытания механической прочности PLA-пластин на трехточечный статический изгиб показали, что данный показатель составляет в среднем ~ 45,1 МПа. Термомеханический анализ полилактида выявил, что в процессе нагрева керамической оболочки выше 150 °С полилактидная модель начинает интенсивно расширяться, оказывая существенное давление на керамическую оболочку. Для уменьшения напряжений в процессе удаления полилактидной модели из керамической формы необходимо максимально увеличить время нагрева в интервале температур 150–300 °С, а также целесообразно использовать пустотелые выжигаемые модели отливки со степенью заполнения ячеистой структуры не более 30 %. При этом напряжения в оболочке не будут превышать ее прочность. С помощью термогравиметрического анализа выявлены характерные температурные характеристики термодеструкции PLA-пластика. Установлено, что материал из полилактида полностью  выгорает  при нагреве до температуры 500 °С, не оставляя после себя остатков золы. Анализ результатов позволил определить технологические режимы выжигания полилактидных моделей из керамических форм. На принтере Picaso 3D Designer (Россия) были напечатаны PLA-модели, которые  использовали  для  получения  опытно-экспериментальных  отливок  из  алюминиевых  сплавов.  Выявлено, что шероховатость поверхности (Ra)  отливки,  полученной  по  выжигаемой  модели,  обработанной  дихлорметаном,  уменьшается на 81,75 % – с 13,7 до 2,5 мкм

Wang Bi\u27s Annotation on Laozi\u27s Place in China and Japan: Focusing on Ogyu Sorai

Wang Bi\u27s Annotation on Laozi 『老子』王弼注 is considered one of the representative notes on Laozi. In Chinahowever, it was not until 1781 when this book was included in Sikuquanshu 『四庫全書』 that the study of Wang Bi\u27s note became popular. In Japan, while Wang Bi\u27s note was introduced before the 5th century, it received rare recognition until Okada Touin\u27s Laozi Daodejing Annotated by Wang Bi 岡田東贇 『老子道徳経王弼注』 published in 1734. However, further research reveals that Ogyu Sorai 荻生徂徠 had pointed out in Keishishiyohran 『経子史要覧』 that, in reading Laozi from the view of classical rhetoric 古文辞学 Wang Bi\u27s annotation should be referred to. Keishishiyohran was based on Sorai\u27s dictation before 1728, and it was earlier than both Okada Touin\u27s Laozi Annotated by Wang Bi (1734) and Sikuquanshu (1781). Therefore< judging from evidences currently available, it seems fair to conclude that Sorai was the pioneer who introduced Wang Bi\u27s annotation into the field of Laozi studies

Enthalpies of solution and enthalpies of solvation of chloro- and nitro-substituted benzenes in 1-butyl-3-methyl imidazolium based ionic liquids at 298.15 K: Additivity of group contributions

© 2016 Elsevier B.V.In this work thermochemistry of solution and solvation of mono- and di-substituted chloro- and nitro-benzenes in 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIM][TfO]) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][NTf2]) ionic liquids was studied. Enthalpies of solution at infinite dilution of benzene, chlorobenzene, nitrobenzene, 1,2-, 1,3-, 1,4-dichlorobenzenes, 1,2-, 1,3-, 1,4-dinitrobenzenes, 1-chloro-2-nitrobenzene, 1-chloro-3-nitrobenzene, and 1-chloro-4-nitrobenzene in three ionic liquids were measured at 298.15 K. On the basis of experimental data enthalpies of solvation of substituted benzenes in ionic solvents were calculated. Values of Cl and NO2 group contributions to the enthalpies of solvation were derived and compared with molecular solvents. Enthalpies of solvation of each series of dichlorobenzenes, chloronitrobenzenes and dinitrobenzenes in studied ionic liquids are equal and do not depend on the mutual position of substituents. This fact shows that dipole moment does not affect the enthalpy of solvation of organic solutes in ionic liquids. Enthalpies of solvation of disubstituted benzenes in ionic liquids calculated through group contribution approach were in good agreement with experimental data

Use of Kinetic Inhibitors of Gas Hydrate Formation in Oil and Gas Production Processes: Current State and Prospects of Development

© 2017, Springer Science+Business Media, LLC. Kinetic inhibitors of gas hydrate formation in oil and gas production processes are reviewed briefly. A general description of the mechanism of inhibitor action is given. The structural distinctions of both synthetic polymeric inhibitors and natural inhibitors are indicated. Prospects of development of new kinetic inhibitors of hydrate formation are shown

Horses for the dead: funerary foodways in Bronze Age Kazakhstan

© 2011 Antiquity PublicationsThe authors examine the role of horses as expressed in assemblages from settlement sites and cemeteries between the Eneolithic and the Bronze Age in Kazakhstan. In this land, known for its rich association with horses, the skeletal evidence appears to indicate a fading of ritual interest. But that's not the whole story, and once again micro-archaeology reveals the true balance. The horses are present at the funeral, but now as meat for the pot, detected in bone fragments and lipids in the pot walls.Natural Environment Research Council (grant NE/B504506) and the British Academy (grants SG-35540 and SG-42656)

Proposed model for bistability in nanowire nonvolatile memory

Cadmium sulfide nanowires of 10‐nm diameter, electrodeposited in porous anodic alumina films, exhibit an electronic bistability that can be harnessed for nonvolatile memory. The current–voltage characteristics of the wires show two stable conductance states that are well separated (conductances differ by more than four orders of magnitude) and long lived (longevity\u3e1 yr at room temperature). These two states can encode binary bits 0 and 1. It is possible to switch between them by varying the voltage across the wires, thus “writing” data. Transport behavior of this system has been investigated at different temperatures in an effort to understand the origin of bistability, and a model is presented to explain the observed features. Based on this model, we estimate that about 40 trapped electrons per nanowire are responsible for the bistability