An improved calibration curve of the pressure shift of the ruby R1 emission line was obtained under quasi-hydrostatic conditions in the diamond-window, high-pressure cell to 800 kbar. Argon was the pressure-transmitting medium. Metallic copper, as a standard, was studied in situ by X ray diffraction. The reference pressure was determined by calibration against known equations of state of the copper sample and by previously obtained data on silver.

Calibration of the ruby pressure gauge to 800 kbar under quasi-hydrostatic conditions

The status of experimental tests of general relativity and of theoretical frameworks for analyzing them is reviewed and updated. Einstein’s equivalence principle (EEP) is well supported by experiments such as the Eotvos experiment, tests of local Lorentz invariance and clock experiments. Ongoing tests of EEP and of the inverse square law are searching for new interactions arising from unification or quantum gravity. Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, the Nordtvedt effect in lunar motion, and frame-dragging. Gravitational wave damping has been detected in an amount that agrees with general relativity to better than half a percent using the Hulse-Taylor binary pulsar, and a growing family of other binary pulsar systems is yielding new tests, especially of strong-field effects. Current and future tests of relativity will center on strong gravity and gravitational waves.

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The Confrontation Between General Relativity and Experiment

As the technology for diamond film preparation by plasma-assisted CVD and related procedures has advanced, Raman spectroscopy has emerged as one of the principal characterization tools for diamond materials. Cubic diamond has a single Raman-active first order phonon mode at the center of the Brillouin zone. The presence of sharp Raman lines allows cubic diamond to be recognized against a background of graphitic carbon and also to characterize the graphitic carbon. Small shifts in the band wavenumber have been related to the stress state of deposited films. The effect is most noticeable in diamond films deposited on hard substrates such as alumina or carbides. The Raman line width varies with mode of preparation of the diamond and has been related to degree of structural order. The Raman spectrum of hexagonal diamond (lonsdaleite) is distinct from that of the cubic diamond and allows it to be recognized.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0884291400004441

Characterization of diamond films by Raman spectroscopy

The field of viscous liquid and glassy solid dynamics is reviewed by a process of posing the key questions that need to be answered, and then providing the best answers available to the authors and their advisors at this time. The subject is divided into four parts, three of them dealing with behavior in different domains of temperature with respect to the glass transition temperature, Tg , and a fourth dealing with ‘‘short time processes.’’ The first part tackles the high temperature regime T.Tg ,i n which the system is ergodic and the evolution of the viscous liquid toward the condition at Tg is in focus. The second part deals with the regime T;Tg , where the system is nonergodic except for very long annealing times, hence has time-dependent properties ~aging and annealing!. The third part discusses behavior when the system is completely frozen with respect to the primary relaxation process but in which secondary processes, particularly those responsible for ‘‘superionic’’ conductivity, and dopart mobility in amorphous silicon, remain active. In the fourth part we focus on the behavior of the system at the crossover between the low frequency vibrational components of the molecular motion and its high frequency relaxational components, paying particular attention to very recent developments in the short time dielectric response and the high Q mechanical response. © 2000 American Institute of Physics.@S0021-8979~00!02213-1#

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1065&context=mse_pubs

Relaxation in glassforming liquids and amorphous solids

The authors reported on investigation of the thermal conductivity of graphene suspended across trenches in Si∕SiO2 wafer. The measurements were performed using a noncontact technique based on micro-Raman spectroscopy. The amount of power dissipated in graphene and corresponding temperature rise were determined from the spectral position and integrated intensity of graphene’s G mode. The extremely high thermal conductivity in the range of ∼3080–5150W∕mK and phonon mean free path of ∼775nm near room temperature were extracted for a set of graphene flakes. The obtained results suggest graphene’s applications as thermal management material in future nanoelectronic circuits.

/pdf/extremely-high-thermal-conductivity-of-graphene-prospects-25qgwo9zzw.pdf

Extremely high thermal conductivity of graphene: Prospects for thermal management applications in nanoelectronic circuits

Visible and near-infra-red transmission and reflectance measurements of the Luna 20 soil.

Analytical and experimental study of iron and titanium in orange glass from Apollo 17 soil sample 74220

A diamond-anvil, high-pressure cell having an apertured steel gasket interposed between the opposed diamonds is lowered into a liquified hydrogen bath at cryogenic temperatures. After the liquid hydrogen permeates the cell through the viewing apertures an initial sealing pressure is applied to the cell by a remotely operated threaded arrangement sufficient to prohibit escape of the liquified hydrogen from the aperture in the steel plate which is closed by the opposed diamonds. The cell is then typically removed from the liquified hydrogen bath and introduced into a lever type pressure applicator to further increase the pressure on the hydrogen at room temperature for the observation of its effects through suitable apertures in the cell and to convert the same to solid form.

Method and apparatus for producing solid hydrogen

Recommendations made in 1974 to the National Academy of Sciences on applications of remote sensing to hydrology research ‘remain valid but mostly unmet,’ concludes a panel of the National Research Council's Space Applications Board. Included with the findings of the Panel on Water Resources are recommendations for research priorities for the 1980's.

Some progress has been made in remote-sensing applications to hydrology, the panel notes. It cites as examples Landsat, Seasat, the Heat Capacity Mapper, and the Landsat-D. However, the application has been too slow, according to the panel.

Peter M. Bell

Papers

Visible and near-infra-red transmission and reflectance measurements of the Luna 20 soil.

Analytical and experimental study of iron and titanium in orange glass from Apollo 17 soil sample 74220

Method and apparatus for producing solid hydrogen

Remote sensing and hydrology

High-pressure FT IR measurements of crystalline methylene chloride up to 120 kbar in the diamond anvil cell