Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “cluster structure”

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 1,423 records · Page 79
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on AsXeO2F7 by Materials Project

XeO2FAsF6 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is zero-dimensional and consists of four AsF6 clusters and four XeO2F clusters. In each AsF6 cluster, As is bonded in an octahedral geometry to six F atoms. There are a spread of As–F bond distances ranging from 1.74–1.82 Å. There are six inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one As atom. In the second F site, F is bonded in a single-bond geometry to one As atom. In the third F site, F is bonded in a single-bond geometry to one As atom. In the fourth F site, F is bonded in a single-bond geometry to one As atom. In the fifth F site, F is bonded in a single-bond geometry to one As atom. In the sixth F site, F is bonded in a single-bond geometry to one As atom. In each XeO2F cluster, Xe is bonded in a distorted trigonal non-coplanar geometry to two O and one F atom. Both Xe–O bond lengths are 1.84 Å. The Xe–F bond length is 2.03 Å. There are two inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Xe atom. In the second O site, O is bonded in a single-bond geometry to one Xe atom. F is bonded in a single-bond geometry to one Xe atom.

36 MATERIALS SCIENCE↗
NASA NTRS1994

Probing the large-scale velocity field with clusters of galaxies

What is the role of clusters of galaxies in probing the large-scale velocity field of the universe? We investigate the distribution of peculiar velocities of clusters of galaxies in the popular low-density (omega = 0.3) flat cold dark matter (CDM) cosmological model, which best fits many large-scale structure observations. An omega = 1 CDM model is also studied for comparison. We find that clusters of galaxies are efficient tracers of the large-scale velocity field. The clusters exhibit a Maxwellian distribution of peculiar velocities, as expected from Gaussian initial density fluctuations. The cluster three-dimensional velocity distribution for the omega = 0.3 model peaks at nu approximately greater than 400 km/s and extends to high velocities of nu approximately 1200 km/s. The rms peculiar velocity of the clusters is 440 km/s. Approximately 10% of all model clusters move with high peculiar velocities nu greater or equal to 700 km/s. The observed velocity distribution of clusters of galaxies is compared with the predictions from cosmological models. The observed data exhibit a larger velocity tail than seen in the model simulations; however, due to the large observational uncertainties, the data are consistent at approximately equal to 3 sigma level with the odel predictions, and with a Gaussian initial density field. The large peculiar velocities reported for some clusters of galaxies (nu approximately greater than 3000 km/s) are likely to be overestimated, if the current model is viable.

Bahcall, Neta A.↗
DOE OSTI2022

Structural transformation of metal oxo species within UiO-66 type metal–organic frameworks

Studying the coordination of actinide-based metal oxo clusters can provide valuable insights for nuclear energy technologies and radioactive waste containment. Metal–organic frameworks serve as a platform to directly interrogate the structure and properties of understudied actinide elements, including thorium. Examples of structural evolutions within Th oxo species within MOFs are rare yet relevant for nuclear waste speciation in solution. Herein, we report the serendipitous discovery of the structural evolution of Th-UiO-66 containing a hexanuclear Th node to a mononuclear Th(bdc) 2 (dmf) 2 upon the evaporation of solvent from the reaction. We observe a partial reversal of Th(bdc) 2 (dmf) 2 back to Th-UiO-66 upon hydrothermal treatment, indicating the complex dynamics of Th oxo species in solution. As a result, we report that isolated Ce-UiO-66 similarly transforms to a newly isolated 1D Ce III carboxylate chain MOF named NU-351 under the same conditions as Th-UiO-66, while Zr-UiO-66 and Hf-UiO-66 retain their structures.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on SeOF2 by Materials Project

SeOF2 crystallizes in the orthorhombic Pca2_1 space group. The structure is zero-dimensional and consists of four SeOF2 clusters. Se4+ is bonded in a distorted trigonal non-coplanar geometry to one O2- and two F1- atoms. The Se–O bond length is 1.63 Å. There is one shorter (1.77 Å) and one longer (1.79 Å) Se–F bond length. O2- is bonded in a single-bond geometry to one Se4+ atom. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one Se4+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one Se4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on W3Br7 by Materials Project

W3Br7 is Copper structured and crystallizes in the cubic Pn-3 space group. The structure is zero-dimensional and consists of four W3Br7 clusters. W+2.33+ is bonded to five Br1- atoms to form edge-sharing WBr5 square pyramids. There are a spread of W–Br bond distances ranging from 2.55–2.66 Å. There are three inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a 6-coordinate geometry to three equivalent W+2.33+ atoms. In the second Br1- site, Br1- is bonded in a 12-coordinate geometry to three equivalent W+2.33+ atoms. In the third Br1- site, Br1- is bonded in a single-bond geometry to one W+2.33+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AsS(ClF2)3 by Materials Project

AsF6SCl3 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is zero-dimensional and consists of four AsF6 clusters and four SCl3 clusters. In each AsF6 cluster, As5+ is bonded in an octahedral geometry to six F1- atoms. There is two shorter (1.77 Å) and four longer (1.78 Å) As–F bond length. There are six inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the third F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the fifth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the sixth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In each SCl3 cluster, S4+ is bonded in a trigonal non-coplanar geometry to three Cl1- atoms. There is two shorter (1.99 Å) and one longer (2.00 Å) S–Cl bond length. There are three inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one S4+ atom. In the second Cl1- site, Cl1- is bonded in a 1-coordinate geometry to one S4+ atom. In the third Cl1- site, Cl1- is bonded in a 1-coordinate geometry to one S4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on S by Materials Project

S is alpha-like structured and crystallizes in the orthorhombic Pnnm space group. The structure is zero-dimensional and consists of two S clusters. there are four inequivalent S sites. In the first S site, S is bonded in a water-like geometry to two S atoms. Both S–S bond lengths are 2.07 Å. In the second S site, S is bonded in a water-like geometry to two equivalent S atoms. Both S–S bond lengths are 2.07 Å. In the third S site, S is bonded in a water-like geometry to two equivalent S atoms. In the fourth S site, S is bonded in a water-like geometry to two S atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PtF6 by Materials Project

PtF6 is beta Np structured and crystallizes in the orthorhombic Pnma space group. The structure is zero-dimensional and consists of four PtF6 clusters. Pt6+ is bonded in an octahedral geometry to six F1- atoms. All Pt–F bond lengths are 1.90 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one Pt6+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one Pt6+ atom. In the third F1- site, F1- is bonded in a single-bond geometry to one Pt6+ atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one Pt6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zr6CI12 by Materials Project

Zr6I12C is Tungsten structured and crystallizes in the trigonal R-3 space group. The structure is zero-dimensional and consists of three Zr6I12C clusters. Zr+2.67+ is bonded in a 5-coordinate geometry to one C4- and four I1- atoms. The Zr–C bond length is 2.27 Å. There are a spread of Zr–I bond distances ranging from 2.90–2.96 Å. C4- is bonded in an octahedral geometry to six equivalent Zr+2.67+ atoms. There are two inequivalent I1- sites. In the first I1- site, I1- is bonded in a 2-coordinate geometry to two equivalent Zr+2.67+ atoms. In the second I1- site, I1- is bonded in a 2-coordinate geometry to two equivalent Zr+2.67+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HI3 by Materials Project

HI3 crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of two HI3 clusters. H is bonded in a single-bond geometry to one I atom. The H–I bond length is 1.65 Å. There are three inequivalent I sites. In the first I site, I is bonded in a 2-coordinate geometry to one I atom. The I–I bond length is 2.72 Å. In the second I site, I is bonded in a single-bond geometry to one H and one I atom. The I–I bond length is 3.45 Å. In the third I site, I is bonded in a bent 150 degrees geometry to two I atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Re3Se4O3 by Materials Project

Re3Se4O3 is Copper structured and crystallizes in the cubic Pa-3 space group. The structure is zero-dimensional and consists of four Re3Se4O3 clusters. Re+4.67+ is bonded in a distorted single-bond geometry to four Se2- and one O2- atom. There are two shorter (2.53 Å) and two longer (2.54 Å) Re–Se bond lengths. The Re–O bond length is 1.70 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Re+4.67+ atoms. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Re+4.67+ atoms. O2- is bonded in a single-bond geometry to one Re+4.67+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CoSn2(OF)6 by Materials Project

CoO6(SnF3)2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of one CoO6 cluster and one SnF3 cluster. In the CoO6 cluster, Co is bonded in an octahedral geometry to six O atoms. There is two shorter (1.72 Å) and four longer (1.92 Å) Co–O bond length. There are three inequivalent O sites. In the first O site, O is bonded in a 2-coordinate geometry to one Co and one O atom. The O–O bond length is 1.29 Å. In the second O site, O is bonded in a 2-coordinate geometry to one Co and one O atom. In the third O site, O is bonded in a single-bond geometry to one Co atom. In the SnF3 cluster, Sn is bonded in a distorted rectangular see-saw-like geometry to four F atoms. There are a spread of Sn–F bond distances ranging from 1.94–2.27 Å. There are three inequivalent F sites. In the first F site, F is bonded in a water-like geometry to two equivalent Sn atoms. In the second F site, F is bonded in a single-bond geometry to one Sn atom. In the third F site, F is bonded in a single-bond geometry to one Sn atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U2Zn17 by Materials Project

U2Zn17 crystallizes in the monoclinic C2/m space group. The structure is zero-dimensional and consists of two U2Zn5 clusters and sixteen zinc molecules. In each U2Zn5 cluster, U is bonded in a bent 150 degrees geometry to two Zn atoms. There are one shorter (2.90 Å) and one longer (3.16 Å) U–Zn bond lengths. There are three inequivalent Zn sites. In the first Zn site, Zn is bonded in a linear geometry to two equivalent U atoms. In the second Zn site, Zn is bonded in a single-bond geometry to one Zn atom. The Zn–Zn bond length is 2.86 Å. In the third Zn site, Zn is bonded in a distorted bent 120 degrees geometry to one U and one Zn atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PtBr3N2 by Materials Project

PtN2Br3 is Indium structured and crystallizes in the orthorhombic Imm2 space group. The structure is zero-dimensional and consists of two PtN2Br3 clusters. Pt5+ is bonded in a distorted trigonal bipyramidal geometry to two equivalent N1- and three Br1- atoms. Both Pt–N bond lengths are 1.77 Å. There are one shorter (2.41 Å) and two longer (2.57 Å) Pt–Br bond lengths. N1- is bonded in a single-bond geometry to one Pt5+ atom. There are two inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a single-bond geometry to one Pt5+ atom. In the second Br1- site, Br1- is bonded in a single-bond geometry to one Pt5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BPd6 by Materials Project

Pd6B is gamma plutonium structured and crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of four Pd6B clusters. there are three inequivalent Pd sites. In the first Pd site, Pd is bonded in a single-bond geometry to one B atom. The Pd–B bond length is 2.08 Å. In the second Pd site, Pd is bonded in a single-bond geometry to one B atom. The Pd–B bond length is 2.08 Å. In the third Pd site, Pd is bonded in a single-bond geometry to one B atom. The Pd–B bond length is 2.07 Å. B is bonded in an octahedral geometry to six Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Structural characterization of an intrinsically disordered protein complex using integrated small-angle neutron scattering and computing

Characterizing structural ensembles of intrinsically disordered proteins (IDPs) and intrinsically disordered regions (IDRs) of proteins is essential for studying structure–function relationships. Due to the different neutron scattering lengths of hydrogen and deuterium, selective labeling and contrast matching in small-angle neutron scattering (SANS) becomes an effective tool to study dynamic structures of disordered systems. However, experimental timescales typically capture measurements averaged over multiple conformations, leaving complex SANS data for disentanglement. We hereby demonstrate an integrated method to elucidate the structural ensemble of a complex formed by two IDRs. We use data from both full contrast and contrast matching with residue-specific deuterium labeling SANS experiments, microsecond all-atom molecular dynamics (MD) simulations with four molecular mechanics force fields, and an autoencoder-based deep learning (DL) algorithm. From our combined approach, we show that selective deuteration provides additional information that helps characterize structural ensembles. We find that among the four force fields, a99SB-disp and CHARMM36m show the strongest agreement with SANS and NMR experiments. In addition, our DL algorithm not only complements conventional structural analysis methods but also successfully differentiates NMR and MD structures which are indistinguishable on the free energy surface. Finally, we present an ensemble that describes experimental SANS and NMR data better than MD ensembles generated by one single force field and reveal three clusters of distinct conformations. Our results demonstrate a new integrated approach for characterizing structural ensembles of IDPs.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Materials Data on BrO2F by Materials Project

O2BrF is Ammonia-derived structured and crystallizes in the monoclinic Cc space group. The structure is zero-dimensional and consists of four O2BrF clusters. there are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one Br5+ atom. The O–Br bond length is 1.63 Å. In the second O2- site, O2- is bonded in a single-bond geometry to one Br5+ atom. The O–Br bond length is 1.63 Å. Br5+ is bonded in a trigonal non-coplanar geometry to two O2- and one F1- atom. The Br–F bond length is 1.89 Å. F1- is bonded in a single-bond geometry to one Br5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SnH6Cl2O11 by Materials Project

Sn(H2O)3(ClO4)2 crystallizes in the hexagonal P6_3 space group. The structure is zero-dimensional and consists of four ClO4 clusters and two Sn(H2O)3 clusters. In each ClO4 cluster, there are two inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Cl atom. The O–Cl bond length is 1.46 Å. In the second O site, O is bonded in a single-bond geometry to one Cl atom. The O–Cl bond length is 1.49 Å. Cl is bonded in a tetrahedral geometry to four O atoms. In each Sn(H2O)3 cluster, Sn is bonded in a 3-coordinate geometry to three equivalent O atoms. All Sn–O bond lengths are 2.28 Å. There are two inequivalent H sites. In the first H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. In the second H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. O is bonded in a distorted water-like geometry to one Sn and two H atoms.

36 MATERIALS SCIENCE↗