Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Re”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Crystal structures and comparisons of potassium rare-earth molybdates KRE(MoO 4 ) 2 (RE = Tb, Dy, Ho, Er, Yb, and Lu)

Six potassium rare-earth molybdates KRE(MoO 4 ) 2 (RE = Tb, Dy, Ho, Er, Yb, and Lu) were synthesized by flux-assisted growth in K 2 Mo 3 O 10 . The crystal structures were determined using single-crystal X-ray diffraction data. The synthesized molybdates crystallize with the orthorhombic Pbcn space group (No. 60). Trendlines for unit-cell parameters were calculated using data from the current study. The unit-cell parameters a and c increase linearly whereas b decreases with larger RE cations, based on crystal radii. The unit-cell volumes increase linearly and the densities decrease linearly with larger RE cations. The average distances between the RE cations and the nearest O atoms increase with larger cations whereas the average distances of Mo—O and K—O do not show specific trends.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Acoustic Observations of the OSIRIS-REx Sample Return Capsule Re-Entry from Wendover Airport

The Origins, Spectral Interpretation, Resource Identification, and Security‐Regolith Explorer sample return capsule (SRC) re‐entered the Earth’s atmosphere at hypersonic speeds from interplanetary space on 24 September 2023. The current work reports on 18 ground‐based acoustic sensors deployed at Wendover Airport, the same location that the Genesis and Stardust SRC re‐entries were recorded. Four different sensors (Chaparral Physics, Gem, Wilson Engineering Research and Development [WERD], and RedVox) were deployed in close proximity to compare their performance. All the sensors captured an N‐wave signal associated with the SRC re‐entry shock wave followed by a broadband coda. The Chaparral Physics array served as the high‐fidelity reference measurement. The N‐wave signal had a peak‐to‐peak amplitude of 4.07 Pa with a fundamental frequency of 4.98 Hz from 167.5° measured clockwise from north, nearly perpendicular to the SRC trajectory. In addition, high coherence in the coda was shown to be associated reflections from the surrounding mountains. In general, the more economical sensors (Gem, WERD, and RedVox) produced results that were consistent with these observations and sensor specifications. Beamforming with these single sensors arranged as an array showed agreement with the high‐fidelity array to within a couple of degrees. Furthermore, the current high‐fidelity results were compared with the measurements during the Genesis and Stardust SRC re‐entries. All three entries produced a broadband fundamental peak at a frequency that was inversely related to the SRC diameter as well as evidence of reflections from the surrounding topography.

KC, Real J. [Oklahoma State University, Stillwater↗
DOE OSTI2020

Materials Data on Re(AgCl3)2 by Materials Project

Re(AgCl3)2 crystallizes in the trigonal R-3 space group. The structure is two-dimensional and consists of three Re(AgCl3)2 sheets oriented in the (0, 0, 1) direction. Re4+ is bonded in an octahedral geometry to six equivalent Cl1- atoms. All Re–Cl bond lengths are 2.38 Å. Ag1+ is bonded in a distorted trigonal planar geometry to three equivalent Cl1- atoms. All Ag–Cl bond lengths are 2.57 Å. Cl1- is bonded in a distorted water-like geometry to one Re4+ and one Ag1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Re(Te4Cl3)2 by Materials Project

ReCl6Re(TeCl3)2(Te)14 crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of four hexachlororhenium molecules, fifty-six tellurium molecules, and four Re(TeCl3)2 clusters. In each Re(TeCl3)2 cluster, Re4+ is bonded in an octahedral geometry to six Cl1- atoms. There are four shorter (2.37 Å) and two longer (2.38 Å) Re–Cl bond lengths. Te+0.25+ is bonded in a single-bond geometry to one Cl1- atom. The Te–Cl bond length is 3.09 Å. There are three inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Re4+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Re4+ atom. In the third Cl1- site, Cl1- is bonded in a distorted water-like geometry to one Re4+ and one Te+0.25+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Re(TeBr2)2 by Materials Project

Re(TeBr2)2 crystallizes in the tetragonal I-4 space group. The structure is three-dimensional. Re7+ is bonded in a 6-coordinate geometry to four Te+1.50- and two Br1- atoms. There are a spread of Re–Te bond distances ranging from 2.64–2.78 Å. There are one shorter (2.67 Å) and one longer (2.68 Å) Re–Br bond lengths. There are two inequivalent Te+1.50- sites. In the first Te+1.50- site, Te+1.50- is bonded in a 2-coordinate geometry to one Re7+ and four Br1- atoms. There are a spread of Te–Br bond distances ranging from 2.59–2.92 Å. In the second Te+1.50- site, Te+1.50- is bonded in a 10-coordinate geometry to three equivalent Re7+ and seven Br1- atoms. There are a spread of Te–Br bond distances ranging from 3.48–3.84 Å. There are four inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a distorted single-bond geometry to three Te+1.50- atoms. In the second Br1- site, Br1- is bonded in a 1-coordinate geometry to one Re7+ and three Te+1.50- atoms. In the third Br1- site, Br1- is bonded in a 1-coordinate geometry to one Re7+ and three Te+1.50- atoms. In the fourth Br1- site, Br1- is bonded in a distorted single-bond geometry to two Te+1.50- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Re(Te2Mo)2 by Materials Project

Re(MoTe2)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Mo+2.50+ sites. In the first Mo+2.50+ site, Mo+2.50+ is bonded to five Te2- atoms to form MoTe5 square pyramids that share corners with two MoTe5 square pyramids, corners with two ReTe5 square pyramids, edges with two ReTe5 square pyramids, and edges with three MoTe5 square pyramids. There are a spread of Mo–Te bond distances ranging from 2.74–2.91 Å. In the second Mo+2.50+ site, Mo+2.50+ is bonded to five Te2- atoms to form MoTe5 square pyramids that share a cornercorner with one ReTe5 square pyramid, corners with three MoTe5 square pyramids, edges with two ReTe5 square pyramids, and edges with three MoTe5 square pyramids. There are a spread of Mo–Te bond distances ranging from 2.72–2.86 Å. In the third Mo+2.50+ site, Mo+2.50+ is bonded to five Te2- atoms to form MoTe5 square pyramids that share a cornercorner with one ReTe5 square pyramid, corners with three MoTe5 square pyramids, edges with two ReTe5 square pyramids, and edges with three MoTe5 square pyramids. There are a spread of Mo–Te bond distances ranging from 2.75–2.87 Å. In the fourth Mo+2.50+ site, Mo+2.50+ is bonded to five Te2- atoms to form MoTe5 square pyramids that share corners with two MoTe5 square pyramids, corners with two ReTe5 square pyramids, edges with two ReTe5 square pyramids, and edges with three MoTe5 square pyramids. There are a spread of Mo–Te bond distances ranging from 2.73–2.90 Å. There are two inequivalent Re3+ sites. In the first Re3+ site, Re3+ is bonded to five Te2- atoms to form ReTe5 square pyramids that share a cornercorner with one ReTe5 square pyramid, corners with three MoTe5 square pyramids, an edgeedge with one ReTe5 square pyramid, and edges with four MoTe5 square pyramids. There are a spread of Re–Te bond distances ranging from 2.73–2.88 Å. In the second Re3+ site, Re3+ is bonded to five Te2- atoms to form ReTe5 square pyramids that share a cornercorner with one ReTe5 square pyramid, corners with three MoTe5 square pyramids, an edgeedge with one ReTe5 square pyramid, and edges with four MoTe5 square pyramids. There are a spread of Re–Te bond distances ranging from 2.73–2.90 Å. There are eight inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 4-coordinate geometry to three Mo+2.50+ and one Re3+ atom. In the second Te2- site, Te2- is bonded in a 4-coordinate geometry to two Mo+2.50+ and two Re3+ atoms. In the third Te2- site, Te2- is bonded in a 4-coordinate geometry to three Mo+2.50+ and one Re3+ atom. In the fourth Te2- site, Te2- is bonded in a 4-coordinate geometry to three Mo+2.50+ and one Re3+ atom. In the fifth Te2- site, Te2- is bonded in a 4-coordinate geometry to three Mo+2.50+ and one Re3+ atom. In the sixth Te2- site, Te2- is bonded in a 4-coordinate geometry to two Mo+2.50+ and two Re3+ atoms. In the seventh Te2- site, Te2- is bonded in a 6-coordinate geometry to one Mo+2.50+ and two Re3+ atoms. In the eighth Te2- site, Te2- is bonded in a 6-coordinate geometry to three Mo+2.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Re(TeCl2)2 by Materials Project

Re(TeCl2)2 crystallizes in the tetragonal I-4 space group. The structure is three-dimensional. Re7+ is bonded in a 6-coordinate geometry to four Te+1.50- and two Cl1- atoms. There are a spread of Re–Te bond distances ranging from 2.63–2.76 Å. There are one shorter (2.51 Å) and one longer (2.52 Å) Re–Cl bond lengths. There are two inequivalent Te+1.50- sites. In the first Te+1.50- site, Te+1.50- is bonded in a 10-coordinate geometry to three equivalent Re7+ and seven Cl1- atoms. There are a spread of Te–Cl bond distances ranging from 3.38–3.82 Å. In the second Te+1.50- site, Te+1.50- is bonded in a 2-coordinate geometry to one Re7+ and five Cl1- atoms. There are a spread of Te–Cl bond distances ranging from 2.39–4.07 Å. There are four inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a distorted single-bond geometry to three Te+1.50- atoms. In the second Cl1- site, Cl1- is bonded in a distorted single-bond geometry to two Te+1.50- atoms. In the third Cl1- site, Cl1- is bonded in a 1-coordinate geometry to one Re7+ and three Te+1.50- atoms. In the fourth Cl1- site, Cl1- is bonded in a 1-coordinate geometry to one Re7+ and four Te+1.50- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Enhancing durability and activity toward oxygen evolution reaction using single-site Re-doped NiFeO x catalysts at ampere-level

NiFeO x materials are known as among the most active catalysts toward oxygen evolution reaction (OER) for hydrogen generation in alkaline media. Nevertheless, the long-term durability of NiFeO x catalysts for OER is still too far to the industrial application. Herein, we prepared a NiFeReO x catalyst with single-site Re dopants and observed that the single-site Re dopants could significantly enhance the durability without compromising the activity. A cell voltage of 1.82 V without iR correction is noted at the current density of 3000 mA cm –2 in anion-exchange membrane water electrolyzer (AEMWE) with NiFeReO x catalyst, and a very small degradation is observed under 2000 and 1000 mA cm –2 , which remarkably outperforms the pristine NiFeO x . Additionally, the overpotential of 305 mV at 10 mA cm –2 is achieved with the NiFeReO x catalyst, which is lower than 50 mV compared with the pristine NiFeO x catalyst, together with a smaller Tafel slope of 54.3 mV dec -1 . The boosted OER durability and activity of the NiFeReO x catalyst could be attributed to the strong electron-withdrawing property of Re 7+ single atoms leading to the electronic structure optimization and stabilization of Ni/Fe active sites. Our insights propose a new path for designing NiFeO x catalysts with high durability and activity toward OER.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Computational analysis of flame initiation, quenching, and re-ignition in a prechamber natural gas engine under varying EGR-dilution levels

The on-road natural-gas (NG) fueled transportation relies on stoichiometric spark-ignition engines for the advantages of simple after-treatment system despite the efficiency penalty relative to lean-burn combustion strategies. Exhaust gas recirculation (EGR) has the potential to reduce this efficiency gap at low to moderate loads without the need for complex lean-exhaust aftertreatment systems. However, EGR dilution leads to reduced combustion stability and increased cycle-to-cycle variability. A promising technology that has the potential to achieve reliable operation under diluted conditions is the prechamber ignition (or turbulent jet ignition) which uses chemically active turbulent jets generated from combustion inside a prechamber to initiate, stabilize and accelerate combustion of the mixture inside the main chamber. The present work focusses on developing a RANS-based CFD approach to accurately reproduce in-cylinder phenomena in a stoichiometric NG prechamber-assisted heavy-duty engine without relying on complex combustion models that account for turbulence-chemistry interactions. This is necessary because reactive prechamber jets at high EGR dilution tend to extinguish while emerging into the main chamber, which is followed by a phase of re-ignition — a phenomenon that conventional G-equation or well-stirred reactor combustion models cannot reproduce. With addition of a damping multiplier to the well-stirred reactor model, the predictions are seen to show good agreement with experimental pressure evolution and combustion images acquired from a single cylinder Cummins N-14 optical diesel engine retrofitted with a prechamber ignition system. Model predictions of local heat release in the flame and temperature evolution inside the flame are used to investigate combustion dynamics in the prechamber and the main chamber. It is seen that the well-stirred reactor model with the inclusion of damping is able to reproduce the temporary reduction in heat release within the flame, which can be considered equivalent to quenching of jets, and the subsequent re-ignition of the flame inside the main chamber. The delay between quenching and re-ignition depends on the amount of dilution, as explained by an illustration of flame evolution in a Borghi diagram.

Prechamber ignition↗
DOE OSTI2026

Optimizing infrasound observations for sample return capsule re-entry: Insights from OSIRIS-REx and Hayabusa2

The atmospheric entry of meteoroids presents a rare and unpredictable phenomenon, posing challenges for systematic observation and detailed characterization. Such events are nonetheless critical for advancing understanding of acoustic wave propagation, atmospheric structure, and entry dynamics. In contrast, sample return capsules (SRCs) from space missions follow well constrained re-entry trajectories, enabling planned observations of shock wave generation and propagation under controlled conditions. This study compares two SRC atmospheric entries, Hayabusa2 in 2020 and OSIRIS-REx in 2023, to assess how different infrasound array configurations influence shock wave detection and trajectory validation. Hayabusa2’s re-entry was monitored using a distributed network of 28 portable infrasound sensors across seven arrays in Woomera, Australia, permitting three-dimensional reconstruction of the trajectory and analysis of wave characteristics. For OSIRIS-REx, a compact four-sensor array deployed near Eureka Airport provided trajectory confirmation through arrival-time differences and back-azimuth estimates. Spectral and waveform analyses revealed differences in signal properties associated with variations in entry angle and velocity. The results illustrate both the strengths and the limitations of the deployed array configurations. The dense and distributed arrays during Hayabusa2’s re-entry enabled detailed trajectory reconstruction, whereas the compact array at Eureka primarily provided confirmation of signal coherence and back-azimuth consistency. These case studies highlight that even relatively small arrays, if located close to the predicted ground track, can still capture useful information on arrival direction and timing. Such insights provide practical guidance for planning future observational campaigns of SRC returns and other controlled atmospheric entries, and may also inform approaches to opportunistic observations of meteoroid events and other atmospheric acoustic phenomena.

celestial mechanics: orbit determination↗
DOE OSTI2021

CERES : a cryo-EM re-refinement system for continuous improvement of deposited models

The field of electron cryomicroscopy (cryo-EM) has advanced quickly in recent years as the result of numerous technological and methodological developments. This has led to an increase in the number of atomic structures determined using this method. Recently, several tools for the analysis of cryo-EM data and models have been developed within the Phenix software package, such as phenix.real_space_refine for the refinement of atomic models against real-space maps. Also, new validation metrics have been developed for low-resolution cryo-EM models. To understand the quality of deposited cryo-EM structures and how they might be improved, models deposited in the Protein Data Bank that have map resolutions of better than 5 Å were automatically re-refined using current versions of Phenix tools. The results are available on a publicly accessible web page (https://cci.lbl.gov/ceres). The implementation of a Cryo-EM Re-refinement System ( CERES ) for the improvement of models deposited in the wwPDB, and the results of the re-refinements, are described. Based on these results, contents are proposed for a `cryo-EM Table 1', which summarizes experimental details and validation metrics in a similar way to `Table 1' in crystallography. The consistent use of robust metrics for the evaluation of cryo-EM models and data should accompany every structure deposition and be reported in scientific publications.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Texture Analysis of Inconel 718 with Different Modes During Single-Track Laser Surface Re-Melting

An in-depth understanding of the texture formation in melt pools allows for the modification of the surface layer microstructure and corresponding material properties, providing an opportunity to integrate laser surface re-melting into metal additive manufacturing. This study investigates crystallographic texture formation at different cooling rates in single melting tracks on the Inconel 718 (IN718) plate produced by laser surface re-melting. The cooling rate varies from 2.31 × 10 5 °C/s to 9.56 × 10 5 °C/s with the increase in scanning rates from 400 mm/s to 1200 mm/s, measured by recently developed real-time temperature monitoring of melt pools. Columnar grains are dominant, with distinct crystallographic textures forming in the melt pools. At a slower scanning speed, the keyhole mode shows three different textures forming at different depths (crystallographically layered structure), while, at a faster scanning speed, the conduction mode shows only random grain orientation. There are no pores/voids detected, and the columnar grain morphology and columnar grain width (8.6 μm to 12.4 μm) follow the analysis framework in terms of thermal gradient and solidification rate analysis. This implies that laser surface re-melting provides the potential to modify the surface structure from a random grain orientation to a crystallographically layered structure.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Unraveling Site Selective Magnetic Properties of Cobalt Sites in Critical Elements Lean RE(TM)5 Magnet Materials

We report here our discovery of crystallographic and interstitial sites and onsite electron correlation propelled intrinsic and derived permanent magnetic properties of critical elements lean RE(TM) 5 (RE = La, Ce and TM = Fe, Co) magnet materials. A full potential linearized augmented plane wave (FP-LAPW) method within the local density approximation (LDA) is used to investigate and analyze the electronic structure and magnetism of these RE(TM) 5 type structures. To better correlate the experimental results, the effective Coulomb (U) and exchange (J) interactions (Hubbard parameters) are crucial at the transition metal sites. Results show that the main propeller of magnetic anisotropy in these compounds is the cobalt atoms at the 2c sites not the 3g sites. This site-specific property and site preference energetics are used to replace 3g sites with non-critical elements such as iron that exhibits a larger magnetic moment. Based on this strategic replacement, we predict two new compounds that have a larger hardness parameter with a relatively large energy product due to the atomic dilution caused by interstitial addition of nitrogen in the compounds: CeCo 2 Fe 3 N 2 and LaCo 2 Fe 3 N 2 .

Rare-earths↗
DOE OSTI2023

Tailoring olefin distribution via tuning rare earth metals in bifunctional Cu-RE/beta-zeolite catalysts for ethanol upgrading

Bioethanol to middle distillate technologies have offered a unique solution to produce renewable aviation fuel for decarbonizing the hard-to-electrify sectors. Here, we have developed the series of bimetallic Cu- and rare earth-containing (RE) Beta zeolite catalysts that yield high C 3+ alkene selectivity from ethanol upgrading (>80% selectivity at ~100% conversion, 623 K). The formation rates of butene isomers to C 5+ alkenes are linearly correlated with the strength of Lewis acidic RE identity, which follows the sequence of Yb 12 /Beta >Y 7 /Beta > Gd 12 /Beta > Ce 10 /Beta > La 12 /Beta. Rate measurements indicate that the RE selection plays the vital role in altering the rate of the key competitive reactions within the ethanol-to-alkenes reaction network, namely C 4 alcohol dehydration and C-C chain growth, which dictate alkene product distributions. Finally, these findings indicate a feasible and promising method for tailoring alkene product distributions from ethanol upgrading, which is of notable significance to the generation of renewable middle distillates.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Beta decay of the axially asymmetric ground state of 192 Re

The β decay of 192 75 Re 117 , which lies near the boundary between the regions of predicted prolate and oblate deformations, has been investigated using the KEK Isotope Separation System (KISS) in RIKEN Nishina Center. This is the first case in which a low-energy beam of rhenium isotope has been successfully extracted from an argon gas-stopping cell using a laser-ionization technique, following production via multi-nucleon transfer between heavy ions. The ground state of 192 Re has been assigned J π = (0⁻) based on the observed β feedings and deduced logft values towards the 0⁺ and 2⁺ states in 192 Os, which is known as a typical γ-soft nucleus. Furthermore, the shape transition from axial symmetry to axial asymmetry in the Re isotopes is discussed from the viewpoint of single-particle structure using the nuclear Skyrme-Hartree-Fock model.

192Re↗
DOE OSTI2026

Syngas Production at Si Hybrid Photoelectrodes Modified with Re(I) and Mn(I) Tricarbonyl Phenanthroline Complexes Containing Reactive Aryl Azide Groups

We installed molecular CO 2 reduction (CO 2 R) catalysts directly onto Si (photo)electrodes. The highly reactive M(5-azido-1,10-phenanthroline)(CO) 3 X (where M = Mn or Re, X = Br or Cl) complexes readily bubbled when dissolved in polar organic solvents, in both the presence and absence of an ultraviolet light source. When placed on hydrogen-terminated Si (H-Si) and native silicon oxide (SiOx), similar amounts of the complex were attached to the surface under illumination (367 nm, 50–200 mW/cm 2 ) or in the dark. Surprisingly, these films revealed submonolayer coverages instead of the multilayered structures we expected. DFT analyses support monolayer formation, showing that the triplet-state nitrene of the complex is more energetically favorable than the singlet state. Using controlled-potential electrolysis experiments, we showed that Re- and Mn-containing films on pSi photoelectrodes generated small amounts of CO when exposed to 1 atm of CO 2 and 1 sun illumination. These amounts of CO were an order of magnitude greater than control surfaces, producing 5.59 × 10 –7 mol CO/h for Re(az-phen) and 7.83 × 10 –7 mol CO/h for Mn(az-phen) films. Much of the charge passed at the pSi electrodes was consumed by the competing hydrogen evolution reaction, which we attribute to the low molecular coverage and the presence of native oxide on the electrode surface after attachment. Finally, this work demonstrates the feasibility of reacting azide-containing ligands with Si surfaces. Still, it highlights the need for alternative ligand structures and reaction conditions to form multilayer films.

azides↗
DOE OSTI2022

Is Jet Re-orientation the Elusive Trigger for Star Formation Suppression in Radio Galaxies?

Abstract Jet re-orientation associated with the time evolution of radio quasars explains the formation of X-shaped radio galaxies and their preference for isolated environments. But since X-shaped radio galaxies are generally not found in dense environments (e.g., groups/clusters), the jet re-orientation phenomenon for radio galaxies in groups and clusters has been ignored. We take a closer look at the re-orientation of FRI jets with respect to FRII jets, and find that it may constitute the as-yet unidentified trigger for star formation suppression in radio galaxies. We show how the recently explored radio “red geyser” galaxies can be interpreted in this context and ultimately reveal a deeper understanding of why FRII radio galaxies are on one side of the star formation enhancement/suppression divide compared to FRI radio galaxies.

Astronomy & Astrophysics↗
DOE OSTI2021

High-pressure study of the low- Z rich superconductor Be 22 Re

With T c ~ 9.6K, Be 22 Re exhibits one of the highest critical temperatures among Be-rich compounds.We have carried out a series of high-pressure electrical resistivity measurements on this compound to 30 GPa. The data show that the critical temperature T c is suppressed gradually at a rate of dT c /dP = –0.05K/GPa. Using density functional theory (DFT) calculations of the electronic and phonon density of states (DOS) and the measured critical temperature, we estimate that the rapid increase in lattice stiffening in Be 22 Re overwhelms a moderate increase in the electron-ion interaction with pressure, resulting in the decrease in T c . Furthermore, high-pressure x-ray diffraction measurements show that the ambient pressure crystal structure of Be 22 Re persists to at least 154 GPa.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗