Research on experimental methods of the melting curve of MC-C large-area high-temperature fixed-point blackbody

Author(s):  
Yihang Xie ◽  
Cai-hong Dai ◽  
Yan-fei Wang ◽  
Zhi-feng Wu ◽  
Ling Li
Metrologia ◽  
2018 ◽  
Vol 55 (2) ◽  
pp. S43-S51 ◽  
Author(s):  
Boris Khlevnoy ◽  
Irina Grigoryeva ◽  
Klaus Anhalt ◽  
Martin Waehmer ◽  
Evgeniy Ivashin ◽  
...  

2014 ◽  
Vol 43 (6) ◽  
pp. 2376-2383 ◽  
Author(s):  
R. Chavez ◽  
S. Angst ◽  
J. Hall ◽  
J. Stoetzel ◽  
V. Kessler ◽  
...  

Author(s):  
Timur Sh. KOMBAEV ◽  
Mikhail K. ARTEMOV ◽  
Valentin K. SYSOEV ◽  
Dmitry S. DEZHIN

It is proposed to develop a small spacecraft for an experiment using high-temperature superconductors (HTS) and shape memory materials. The purpose of the experiment is to test a technological capability of creating a strong magnetic field on the small spacecraft using HTS and shape memory materials for deployed large-area structures, and study the magnetic field interaction with the solar wind plasma and the resulting force impact on the small spacecraft. This article is of a polemical character and makes it possible to take a fresh look at the applicability of new technologies in space-system engineering. Key words: high-temperature superconductors, shape memory materials, solar wind, spacecraft.


2011 ◽  
Vol 679-680 ◽  
pp. 777-780 ◽  
Author(s):  
Shoji Ushio ◽  
Ayumu Adachi ◽  
Kazuhiro Matsuda ◽  
Noboru Ohtani ◽  
Tadaaki Kaneko

As a new graphene functionality applicable to post-implantation high temperature annealing of SiC, a method of in situ formation and removal of large area epitaxial few-layer graphene on 4H-SiC(0001) Si-face is proposed. It is demonstrated that the homogeneous graphene layer formed by Si sublimation can be preserved without the decomposition of the underlying SiC substrate even in the excess of 2000 oC in ultrahigh vacuum. It is due to the existence of the stable (6√3×6√3) buffer layer at the interface. To ensure this cap function, the homogeneity of the interface must be guaranteed. In order to do that, precise control of the initial SiC surface flatness is required. Si-vapor etching is a simple and versatile SiC surface pre/post- treatment method, where thermally decomposed SiC surface is compensated by a Si-vapor flux from Si solid source in the same semi-closed TaC container. While this Si-vapor etching allows precise control of SiC etch depth and surface step-terrace structures, it also provides a “decap” function to remove of the graphene layer. The surface properties after the each process were characterized by AFM and Raman spectroscopy.


MRS Bulletin ◽  
1998 ◽  
Vol 23 (9) ◽  
pp. 16-21 ◽  
Author(s):  
Dieter M. Gruen ◽  
Ian Buckley-Golder

Carbon in the form of diamond is the stuff of dreams, and the image of the diamond evokes deep and powerful emotions in humans. Following the successful synthesis of diamond by high-pressure methods in the 1950s, the startling development of the low-pressure synthesis of diamond films in the 1970s and 1980s almost immediately engendered great expectations of utility. The many remarkable properties of diamond due in part to its being the most atomically dense material in the universe (hardness, thermal conductivity, friction coefficient, transparency, etc.) could at last be put to use in a multitude of practical applications. “The holy grail”—it was realized early on—would be the development of large-area, doped, single-crystal diamond wafers for the fabrication of high-temperature, extremely fast integrated circuits leading to a revolution in computer technology.Excitement in the community of chemical-vapor-deposition (CVD) diamond researchers, funding agencies, and industrial companies ran high in expectation of early realization for many of the commercial goals that had been envisioned: tool, optical, and corrosion-resistant coatings; flat-panel displays; thermomanagement for electronic components, etc. Market projection predicting diamond-film sales in the billions of dollars by the year 2000 was commonplace. Hopes were dashed when these optimistic predictions ran up against the enormous scientific and technical problems that had to be overcome in order for those involved to fully exploit the potential of diamond. This experience is not new to the scientific community. One need only remind oneself of the hopes for cheap nuclear power or for high-temperature superconducting wires available at hardware stores to realize that the lag between scientific discoveries and their large-scale applications can be very long. Diamond films are in fact being used today in commercial applications.


Author(s):  
Timur KOMBAEV ◽  
Mikhail ARTEMOV ◽  
Valentin SYSOEV ◽  
Dmitry DEZHIN ◽  

It is proposed to develop a small spacecraft for an experiment using high-temperature superconductors (HTS) and shape memory materials. The purpose of the experiment is to test a technological capability of creating a strong magnetic field on the small spacecraft using HTS and shape memory materials for deployed large-area structures, and study the magnetic field interaction with the solar wind plasma and the resulting force impact on the small spacecraft. This article is of a polemical character and makes it possible to take a fresh look at the applicability of new technologies in space-system engineering.


2017 ◽  
Vol 114 (13) ◽  
pp. 3375-3380 ◽  
Author(s):  
Yu Shu ◽  
Dongli Yu ◽  
Wentao Hu ◽  
Yanbin Wang ◽  
Guoyin Shen ◽  
...  

As an archetypal semimetal with complex and anisotropic Fermi surface and unusual electric properties (e.g., high electrical resistance, large magnetoresistance, and giant Hall effect), bismuth (Bi) has played a critical role in metal physics. In general, Bi displays diamagnetism with a high volumetric susceptibility (∼10−4). Here, we report unusual ferromagnetism in bulk Bi samples recovered from a molten state at pressures of 1.4–2.5 GPa and temperatures above ∼1,250 K. The ferromagnetism is associated with a surprising structural memory effect in the molten state. On heating, low-temperature Bi liquid (L) transforms to a more randomly disordered high-temperature liquid (L′) around 1,250 K. By cooling from above 1,250 K, certain structural characteristics of liquid L′ are preserved in L. Bi clusters with characteristics of the liquid L′ motifs are further preserved through solidification into the Bi-II phase across the pressure-independent melting curve, which may be responsible for the observed ferromagnetism.


Author(s):  
K. Elliott Cramer ◽  
William P. Winfree ◽  
Edward R. Generazio ◽  
Ramakrishna Bhatt ◽  
Dennis S. Fox ◽  
...  

Strong, tough, high temperature ceramic matrix composites are currently being developed for application in advanced heat engines. One of the most promising of these new materials is a SiC fiber-reinforced silicon nitride ceramic matrix composite (SiCf/Si3N4). The interfacial shear strength in such composites is dependant on the integrity of the fiber’s carbon coating at the fiber-matrix interface. The integrity of the carbon rich interface can be significantly reduced if the carbon is oxidized. Since the thermal diffusivity of the fiber is greater than that of the matrix material, the removal of carbon increases the contact resistance at the interface reducing the thermal diffusivity of the composite. Therefore thermal diffusivity images can be used to characterize the progression of carbon depletion and degradation of the composite. A new thermal imaging technique has been developed to provide rapid large area measurements of the thermal diffusivity perpendicular to the fiber direction in these composites. Results of diffusivity measurements will be presented for a series of SiCf/Si3N4 (reaction bonded silicon nitride) composite samples heat-treated under various conditions. Additionally, the ability of this technique to characterize damage in both ceramic and other high temperature composites will be shown.


2013 ◽  
Author(s):  
G. Machin ◽  
K. Anhalt ◽  
P. Bloembergen ◽  
M. Sadli ◽  
Y. Yamada ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document