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1.
2.
The reactivity of O-, T- and R-phases of the high pressure-high temperature (HPHT) polymerized C60 towards gaseous fluorine in the temperature range of 50-250 °C was investigated. The reaction products were characterized by FTIR, powder X-ray diffraction, SEM, EDX, and VTP-EIMS to determine the bulk stoichiometries, bonding patterns, phase compositions, crystalline structures and thermal decomposition behavior of the fluorinated polymers. At 1 h isothermal treatment duration, fluorinated products with various bulk stoichiometries were obtained from different polymer phases with the R-phase showing the highest fluorine uptake. At 250 °C, all C60 polymers showed partial decomposition to unfluorinated C60 monomer under fluorine atmosphere. At 200 °C, the fluorination of R-phase yielded a pure fluoropolymer most likely having a {C60Fx}n (x = 36-44) composition. The same fluoropolymer was presumably obtained from O- and T-phases in lower yields. The linear chain structure was suggested for this new fluorocarbon polymer in agreement with the molecular mechanics modeling calculations. 相似文献
3.
Healing Effect of Controlled Anti‐Electromigration on Conventional and High‐Tc Superconducting Nanowires
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Xavier D. A. Baumans Joseph Lombardo Jérémy Brisbois Gorky Shaw Vyacheslav S. Zharinov Ge He Heshan Yu Jie Yuan Beiyi Zhu Kui Jin Roman B. G. Kramer Joris Van de Vondel Alejandro V. Silhanek 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(26)
The electromigration process has the potential capability to move atoms one by one when properly controlled. It is therefore an appealing tool to tune the cross section of monoatomic compounds with ultimate resolution or, in the case of polyatomic compounds, to change the stoichiometry with the same atomic precision. As demonstrated here, a combination of electromigration and anti‐electromigration can be used to reversibly displace atoms with a high degree of control. This enables a fine adjustment of the superconducting properties of Al weak links, whereas in Nb the diffusion of atoms leads to a more irreversible process. In a superconductor with a complex unit cell (La2?x Cex CuO4), the electromigration process acts selectively on the oxygen atoms with no apparent modification of the structure. This allows to adjust the doping of this compound and switch from a superconducting to an insulating state in a nearly reversible fashion. In addition, the conditions needed to replace feedback controlled electromigration by a simpler technique of electropulsing are discussed. These findings have a direct practical application as a method to explore the dependence of the characteristic parameters on the exact oxygen content and pave the way for a reversible control of local properties of nanowires. 相似文献
4.
Data conversion from a 3D raster to spiral coordinates is the key function in the scanning process for Roll Powder Sintering (RPS) additive manufacturing technology. Conversion process is especially important, as it produces the basis for a processed object. There are many equations for such conformal transformation, but there is still room to improve the computation efficiency. This paper presents an efficient conversion algorithm, which processes 3D objects and linear transforming it into rolling ribbon. The new algorithm has several significant advantages over the old ones due to applying only one main linear equation. The program based on the linear algorithm is simpler, more compact and faster in comparison to other programs which use trigonometric, transcendental or other equations. The proposed algorithm has been developed and extensively tested on several parts of computer-aided design models for RPS processing. 相似文献
5.
Sotirios Liaskos Shakil M. Khan Marin Litoiu Marina Daoud Jungblut Vyacheslav Rogozhkin John Mylopoulos 《Information Systems》2012
Customizing software to perfectly fit individual needs is becoming increasingly important in information systems engineering. Users want to be able to customize software behavior through reference to terms familiar to their diverse needs and experience. We present a requirements-driven approach to behavioral customization of software systems. Goal models are constructed to represent alternative behaviors that users can exhibit to achieve their goals. Customization information is then added to restrict the space of possibilities to those that fit specific users, contexts, or situations. Meanwhile, elements of the goal models are mapped to units of source code. This way, customization preferences posed at the requirements level are directly translated into system customizations. Our approach, which we apply to an on-line shopping cart system and an automated teller machine simulator, does not assume adoption of a particular development methodology, platform, or variability implementation technique and keeps the reasoning computation overhead from interfering with the execution of the configured application. 相似文献
6.
One of the many complex problems that arise from the transmission and marketing of natural gas is when a shipper draws a contract
with a pipeline company to deliver a certain amount of gas among several points. What is actually delivered is often different
from the amount that had been originally agreed upon. This phenomenon is called an imbalance. When an imbalance occurs, the pipeline penalizes the shipper by imposing a cash-out penalty policy. Since this penalty is
a function of the operating daily imbalances, an important decision-making problem for the shippers is how to carry out their
daily imbalances so as to minimize their incurred penalty.
In this paper, we introduce the problem of minimizing the cash-out penalty costs from the point of view of a natural gas shipping
party. We present a mixed integer bilevel linear programming model and discuss its underlying assumptions. To solve it efficiently,
we reformulate it as a standard mathematical program and describe a penalty-function algorithm functions for its solution.
The algorithm is well-founded and its convergence is proved. Results of numerical experiments support the algorithm’s robustness
providing a valuable solution technique for this very important and complex problem in the natural gas market. 相似文献
7.
Victor Prikhodko Igor Yarygin Vyacheslav Yarygin 《Microgravity science and technology》2009,21(Z1):277-281
We present the experimental research on the interaction of co-current gas flow with near-wall liquid film for gas velocities
up to 300 m/s. Local parameters of near-wall liquid film are measured by using capacity-type probes. It is shown that co-current
gas flow has strong influence on near-wall liquid film, leading to intensive wave formation, detachment of droplets from the
film surface and their entrainment by the gas flow. Thus it is shown that the relative amount of liquid carried away by co-current
gas flow is well characterized by Weber number of gas flow. A model for the motion of a film with co-current flow, connecting
a thickness and velocity of the film with value of shearing stress at gas-liquid boundary, is suggested. It is shown that
intensive wave formation leads to essential increase of the interphase friction value. 相似文献
8.
Wanchuck Woo Vyacheslav EmPavel Mikula Gyu-Baek AnBaek-Seok Seong 《Materials Science and Engineering: A》2011,528(12):4120-4124
Residual stresses were determined through the thickness of a 50 mm thick ferrite steel weld plate using neutron diffraction. Whereas the limiting penetration depth for iron-based alloys is about 25 mm in the most typical neutron diffractometers, we significantly enhanced the penetration depth up to 50 mm with 2 mm spatial resolution by using the neutron wavelength of 2.39 Å. The selected wavelength minimizes the total neutron cross-section and beam attenuation, thereby, maximizes the neutron fluxes at depth. Two-dimensional mapping of the residual stresses shows that significant amounts of the tensile longitudinal stresses (over 90% of yield strength) were developed along the heat-affected zone of the weld. 相似文献
9.
Residual stress determination in a dissimilar weld overlay pipe by neutron diffraction 总被引:2,自引:0,他引:2
Wanchuck Woo Vyacheslav EmCamden R. Hubbard Ho-Jin LeeKwang Soo Park 《Materials Science and Engineering: A》2011,528(27):8021-8027
Residual stresses were determined through the thickness of a dissimilar weld overlay pipe using neutron diffraction. The specimen has a complex joining structure consisting of a ferritic steel (SA508), austenitic steel (F316L), Ni-based consumable (Alloy 182), and overlay of Ni-base superalloy (Alloy 52M). It simulates pressurized nozzle components, which have been a critical issue under the severe crack condition of nuclear power reactors. Two neutron diffractometers with different spatial resolutions have been utilized on the identical specimen for comparison. The macroscopic ‘stress-free’ lattice spacing (do) was also obtained from both using a 2-mm width comb-like coupon. The results show significant changes in residual stresses from tension (300-400 MPa) to compression (−600 MPa) through the thickness of the dissimilar weld overlay pipe specimen. 相似文献
10.
Sergei V. Kostjuk Alexei Yu. Dubovik Irina V. Vasilenkol Vyacheslav P. Mardykin Ludmila V. Gaponik Fyodor N. Kaputsky Lev M. Antipin 《Polymer Bulletin》2004,52(3-4):227-234
Summary
Quasiliving cationic polymerization of styrene was obtained in the system 2-phenyl-2-propano-/AlCl3·OBu2/Bu2O in a mixture of 1,2-dichloroethane and n-hexane (55:45 viv) at -15 °C. The molecular weights of the polymers (Mn) increased in direct proportion to the monomer conversion. However, the experimental Mns are essentially higher than theoretical ones, indicating that slow initiation relative to propagation takes place. The molecular weight distributions were broad (Mw/Mn2.5), probably due to the slow initiation and slow exchange between reversibly terminated and propagating species. 相似文献