Respublika mechei ili torgovaia respublika ?

Les auteurs analysent la représentation qui est faite de la toute puissante république de Novgorod dans les écrits historiques et politiques russes du xviiie – début du xixe siècle. Dans la tradition européenne, la république classique est une république militaire, qui s’appuie sur le modèle de la république romaine militairement puissante. En opposition, la république commerciale est considérée comme un petit État, inférieure militairement aux grandes monarchies. La pensée sociale russe, à commencer par celle développée par A.I. Mankiev, identifie Novgorod à une république mais demeure ambivalente dans l’évaluation de sa puissance militaire. Sous l’influence de l’imagerie romaine et du discours général « de gloire et de grandeur » de la fin du xviiie siècle, un canon s’est mis en place, qui fait de l’ancienne Novgorod « une république militaire » tout en conservant la république commerciale comme outil conceptuel pour l’analyse de l’histoire ultérieure de la ville. La reconnaissance d’un pouvoir militaire à la république de Novgorod sape l’un des arguments clés en faveur de la monarchie, selon lequel seule une monarchie est capable de contrôler et défendre efficacement un large territoire. De ce fait, l’évaluation de Novgorod en tant que république militaire marque une étape importante dans l’apparition dans la société russe du xixe siècle d’une alternative républicaine à un monarchisme apparemment inébranlable.The authors analyze how the powerful Republic of Novgorod was represented in Russian historical and political writing between the eighteenth and early nineteenth centuries. In the European tradition, a republic typically was military and modeled on the Roman Republic and its military strength. In contrast, the trading republic was considered a small state, militarily inferior to great monarchies. Russian social thought, starting with A.I. Mankiev’s, identified Novgorod with a military republic while remaining ambivalent in assessing its military might. The influence of Roman imagery and the general discourse on “glory and grandeur” of the late eighteenth century brought about the emergence of a model of old Novgorod as a military republic and set aside the trading republic as a conceptual toolkit for studying the town’s future historical development. Recognition of military power in the Republic of Novgorod undermined one of the key arguments in favor of monarchy – the claim that monarchy alone is able to effectively control and protect a vast territory. Thus, viewing Novgorod as a military republic was an important step towards the rise, in early‑nineteenth‑century Russian society, of a republican alternative to a seemingly immutable monarchy

Review of the problems of additive manufacturing of nanostructured high-energy materials

This article dwells upon the additive manufacturing of high-energy materials (HEM) with regards to the problems of this technology’s development. This work is aimed at identifying and describing the main problems currently arising in the use of AM for nanostructured highenergy materials and gives an idea of the valuable opportunities that it provides in the hope of promoting further development in this area. Original approaches are proposed for solving one of the main problems in the production of nanostructured HEM—safety and viscosity reduction of the polymer-nanopowder system. Studies have shown an almost complete degree of deagglomeration of microencapsulated aluminum powders. Such powders have the potential to create new systems for safe 3D printing using high-energy materials

Phase composition, structure and properties of the spark plasma sintered ceramics obtained from the Al12Mg17-B-Si powder mixtures

In this work, composite materials were obtained by spark plasma sintering of an Al12Mg17-B-Si powder mixture. The structure, phase composition, and mechanical properties of the obtained composites were studied. It was found that various compounds based on B12 icosahedrons, such as AlB12, B4Si, and B6Si, are formed during spark plasma sintering. Based on the SEM images and results of XRD analysis of the obtained specimens, a probable scheme for the formation of the phase composition of composite materials during spark plasma sintering was proposed. An increase in the Al12Mg17-B powder content in the initial mixture from 30 to 70 wt% leads to an increase in hardness from 16.55 to 21.24 GPa and a decrease in the friction coefficient and wear rate from 0.56 to 0.32 and 13.60 to 5.60 10−5 mm−3/(N/m), respectively

Spectral Shape of Relaxations in Silica Glass

Precise low-frequency light scattering experiments on silica glass are presented, covering a broad temperature and frequency range (9 GHz < \nu < 2 THz). For the first time the spectral shape of relaxations is observed over more than one decade in frequency. The spectra show a power-law low-frequency wing of the relaxational part of the spectrum with an exponent $\alpha$ proportional to temperature in the range 30 K < T < 200 K. A comparison of our results with those from acoustic attenuation experiments performed at different frequencies shows that this power-law behaviour rather well describes relaxations in silica over 9 orders of magnitude in frequency. These findings can be explained by a model of thermally activated transitions in double well potentials.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let

The ALICE experiment at the CERN LHC

ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries. Its overall dimensions are 161626 m3 with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008

Gas dynamics features of physico-chemical processes in the SRM large-sized charges at open firing

The problem of utilization of solid rocket motors (SRM) large-sized charges is a relevant objective. This is due to the decommissioning of SRM that failed or were rejected during production and operation, as well as with the implementation of strategic arms reduction treaties. Comparative analysis of SRM large-sized charge utilization methods showed that the simplest, most productive, and relatively safe technique is open firing. At the same time, the information on the dynamics of harmful substances emission into the environment is needed to conduct quantitative assessment of the concentrations of environmentally hazardous combustion products formed during open firing. The calculation of intraballistic parameters in SRM makes it possible to estimate the consumption parameters of harmful gaseous and condensed combustion products entering the atmosphere. Also, it allows analyze the spatial and temporal course of the concentrations of these substances and optimize ways to reduce environmental hazards. The mathematical model and results of gas dynamics parameters calculation at the open firing of large-sized SRM with the demounted nozzle unit and forward bottom are submitted. The key features of realized flow modes are marked: availability of significant pressure differentials along the length of the SRM in the initial stage of its activity; realized transonic velocities of intrachannel flow; the essential influence of erosion on the initial stages of burning rate

On the structure and properties of AlMgB14-TiB2 composites obtained from SHS powders by spark plasma sintering

AlMgB14-TiB2 composite materials were fabricated by self-propagating high-temperature synthesis (SHS) followed by spark plasma sintering of the obtained SHS products. It was found that, during the SHS, the AlMgB14 phase is formed at a donor (Ti + 2B) to acceptor (Al12Mg17-B) mass ratio of 3:7 and 4:6, respectively. The specimen sintered from the SHS powder with the donor:acceptor mass ratio of 5:5 at a temperature of 1470 C has a uniform skeletal structure. The average hardness of the obtained specimen is 30.1 GPa