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At least 1,693 records · Page 94
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on InGe3 by Materials Project

InGe3 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. In is bonded to twelve Ge atoms to form a mixture of face, edge, and corner-sharing InGe12 cuboctahedra. There are four shorter (3.02 Å) and eight longer (3.22 Å) In–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 8-coordinate geometry to four equivalent In and four equivalent Ge atoms. All Ge–Ge bond lengths are 3.02 Å. In the second Ge site, Ge is bonded in a square co-planar geometry to four equivalent In atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CeGe3Ru by Materials Project

CeRuGe3 crystallizes in the cubic Pm-3n space group. The structure is three-dimensional. there are two inequivalent Ce sites. In the first Ce site, Ce is bonded in a 8-coordinate geometry to four equivalent Ru and twelve equivalent Ge atoms. All Ce–Ru bond lengths are 3.21 Å. There are eight shorter (3.09 Å) and four longer (3.22 Å) Ce–Ge bond lengths. In the second Ce site, Ce is bonded in a cuboctahedral geometry to twelve equivalent Ge atoms. All Ce–Ge bond lengths are 3.26 Å. Ru is bonded in a 9-coordinate geometry to three equivalent Ce and six equivalent Ge atoms. All Ru–Ge bond lengths are 2.53 Å. Ge is bonded in a 2-coordinate geometry to four Ce, two equivalent Ru, and three equivalent Ge atoms. There are one shorter (2.77 Å) and two longer (2.85 Å) Ge–Ge bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LaGe2IrRu by Materials Project

LaRuIrGe2 crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. La is bonded in a 8-coordinate geometry to four equivalent Ru, four equivalent Ir, and eight equivalent Ge atoms. All La–Ru bond lengths are 3.37 Å. All La–Ir bond lengths are 3.37 Å. All La–Ge bond lengths are 3.32 Å. Ru is bonded in a 4-coordinate geometry to four equivalent La and four equivalent Ge atoms. All Ru–Ge bond lengths are 2.48 Å. Ir is bonded in a 4-coordinate geometry to four equivalent La and four equivalent Ge atoms. All Ir–Ge bond lengths are 2.48 Å. Ge is bonded in a 9-coordinate geometry to four equivalent La, two equivalent Ru, two equivalent Ir, and one Ge atom. The Ge–Ge bond length is 2.71 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ce2NiGe3 by Materials Project

Ce2NiGe3 is hexagonal omega structure-derived structured and crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are two inequivalent Ce sites. In the first Ce site, Ce is bonded to twelve equivalent Ge atoms to form CeGe12 cuboctahedra that share edges with twelve equivalent CeNi4Ge8 cuboctahedra and faces with eight CeGe12 cuboctahedra. All Ce–Ge bond lengths are 3.24 Å. In the second Ce site, Ce is bonded to four equivalent Ni and eight equivalent Ge atoms to form a mixture of edge and face-sharing CeNi4Ge8 cuboctahedra. All Ce–Ni bond lengths are 3.17 Å. There are four shorter (3.13 Å) and four longer (3.16 Å) Ce–Ge bond lengths. Ni is bonded in a 3-coordinate geometry to six equivalent Ce and three equivalent Ge atoms. All Ni–Ge bond lengths are 2.31 Å. Ge is bonded in a 1-coordinate geometry to six Ce, one Ni, and two equivalent Ge atoms. There are one shorter (2.48 Å) and one longer (2.49 Å) Ge–Ge bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LaMnCuGe2 by Materials Project

LaMnCuGe2 crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. La is bonded in a 8-coordinate geometry to four equivalent Mn, four equivalent Cu, and eight equivalent Ge atoms. All La–Mn bond lengths are 3.39 Å. All La–Cu bond lengths are 3.39 Å. All La–Ge bond lengths are 3.26 Å. Mn is bonded to four equivalent La, four equivalent Cu, and four equivalent Ge atoms to form distorted MnLa4Cu4Ge4 tetrahedra that share corners with four equivalent CuLa4Mn4Ge4 cuboctahedra, corners with twelve equivalent MnLa4Cu4Ge4 tetrahedra, edges with two equivalent CuLa4Mn4Ge4 cuboctahedra, faces with four equivalent CuLa4Mn4Ge4 cuboctahedra, and faces with four equivalent MnLa4Cu4Ge4 tetrahedra. All Mn–Cu bond lengths are 2.98 Å. All Mn–Ge bond lengths are 2.50 Å. Cu is bonded to four equivalent La, four equivalent Mn, and four equivalent Ge atoms to form distorted CuLa4Mn4Ge4 cuboctahedra that share corners with twelve equivalent CuLa4Mn4Ge4 cuboctahedra, corners with four equivalent MnLa4Cu4Ge4 tetrahedra, edges with two equivalent MnLa4Cu4Ge4 tetrahedra, faces with four equivalent CuLa4Mn4Ge4 cuboctahedra, and faces with four equivalent MnLa4Cu4Ge4 tetrahedra. All Cu–Ge bond lengths are 2.50 Å. Ge is bonded in a 9-coordinate geometry to four equivalent La, two equivalent Mn, two equivalent Cu, and one Ge atom. The Ge–Ge bond length is 2.61 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on UCuNiGe2 by Materials Project

UNiCuGe2 crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to four equivalent Ni, four equivalent Cu, and eight equivalent Ge atoms. All U–Ni bond lengths are 3.22 Å. All U–Cu bond lengths are 3.22 Å. All U–Ge bond lengths are 3.12 Å. Ni is bonded to four equivalent U and four equivalent Ge atoms to form distorted NiU4Ge4 tetrahedra that share corners with four equivalent CuU4Ge4 tetrahedra, corners with eight equivalent NiU4Ge4 tetrahedra, edges with two equivalent CuU4Ge4 tetrahedra, edges with four equivalent NiU4Ge4 tetrahedra, and faces with four equivalent CuU4Ge4 tetrahedra. All Ni–Ge bond lengths are 2.39 Å. Cu is bonded to four equivalent U and four equivalent Ge atoms to form distorted CuU4Ge4 tetrahedra that share corners with four equivalent NiU4Ge4 tetrahedra, corners with eight equivalent CuU4Ge4 tetrahedra, edges with two equivalent NiU4Ge4 tetrahedra, edges with four equivalent CuU4Ge4 tetrahedra, and faces with four equivalent NiU4Ge4 tetrahedra. All Cu–Ge bond lengths are 2.39 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, two equivalent Ni, two equivalent Cu, and one Ge atom. The Ge–Ge bond length is 2.46 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CdGe3 by Materials Project

CdGe3 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Cd is bonded to twelve Ge atoms to form a mixture of corner, edge, and face-sharing CdGe12 cuboctahedra. There are four shorter (2.99 Å) and eight longer (3.15 Å) Cd–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 12-coordinate geometry to four equivalent Cd and four equivalent Ge atoms. All Ge–Ge bond lengths are 2.99 Å. In the second Ge site, Ge is bonded in a square co-planar geometry to four equivalent Cd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaMnFeGe2 by Materials Project

CaMnFeGe2 crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. Ca is bonded in a 8-coordinate geometry to four equivalent Fe and eight equivalent Ge atoms. All Ca–Fe bond lengths are 3.40 Å. All Ca–Ge bond lengths are 3.09 Å. Mn is bonded to four equivalent Fe and four equivalent Ge atoms to form a mixture of distorted face and corner-sharing MnFe4Ge4 tetrahedra. All Mn–Fe bond lengths are 2.78 Å. All Mn–Ge bond lengths are 2.43 Å. Fe is bonded in a 12-coordinate geometry to four equivalent Ca, four equivalent Mn, and four equivalent Ge atoms. All Fe–Ge bond lengths are 2.43 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Ca, two equivalent Mn, two equivalent Fe, and one Ge atom. The Ge–Ge bond length is 2.70 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on UCoCuGe2 by Materials Project

UCoCuGe2 crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to four equivalent Co, four equivalent Cu, and eight equivalent Ge atoms. All U–Co bond lengths are 3.18 Å. All U–Cu bond lengths are 3.18 Å. All U–Ge bond lengths are 3.10 Å. Co is bonded to four equivalent U and four equivalent Ge atoms to form distorted CoU4Ge4 tetrahedra that share corners with four equivalent CuU4Ge4 tetrahedra, corners with eight equivalent CoU4Ge4 tetrahedra, edges with two equivalent CuU4Ge4 tetrahedra, edges with four equivalent CoU4Ge4 tetrahedra, and faces with four equivalent CuU4Ge4 tetrahedra. All Co–Ge bond lengths are 2.37 Å. Cu is bonded to four equivalent U and four equivalent Ge atoms to form distorted CuU4Ge4 tetrahedra that share corners with four equivalent CoU4Ge4 tetrahedra, corners with eight equivalent CuU4Ge4 tetrahedra, edges with two equivalent CoU4Ge4 tetrahedra, edges with four equivalent CuU4Ge4 tetrahedra, and faces with four equivalent CoU4Ge4 tetrahedra. All Cu–Ge bond lengths are 2.37 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, two equivalent Co, two equivalent Cu, and one Ge atom. The Ge–Ge bond length is 2.43 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrMnCoGe2 by Materials Project

PrMnCoGe2 crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. Pr is bonded in a 8-coordinate geometry to four equivalent Mn, four equivalent Co, and eight equivalent Ge atoms. All Pr–Mn bond lengths are 3.34 Å. All Pr–Co bond lengths are 3.34 Å. All Pr–Ge bond lengths are 3.17 Å. Mn is bonded to four equivalent Pr, four equivalent Co, and four equivalent Ge atoms to form distorted MnPr4Co4Ge4 tetrahedra that share corners with four equivalent CoPr4Mn4Ge4 cuboctahedra, corners with twelve equivalent MnPr4Co4Ge4 tetrahedra, edges with two equivalent CoPr4Mn4Ge4 cuboctahedra, faces with four equivalent CoPr4Mn4Ge4 cuboctahedra, and faces with four equivalent MnPr4Co4Ge4 tetrahedra. All Mn–Co bond lengths are 2.88 Å. All Mn–Ge bond lengths are 2.43 Å. Co is bonded to four equivalent Pr, four equivalent Mn, and four equivalent Ge atoms to form distorted CoPr4Mn4Ge4 cuboctahedra that share corners with twelve equivalent CoPr4Mn4Ge4 cuboctahedra, corners with four equivalent MnPr4Co4Ge4 tetrahedra, edges with two equivalent MnPr4Co4Ge4 tetrahedra, faces with four equivalent CoPr4Mn4Ge4 cuboctahedra, and faces with four equivalent MnPr4Co4Ge4 tetrahedra. All Co–Ge bond lengths are 2.43 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Pr, two equivalent Mn, two equivalent Co, and one Ge atom. The Ge–Ge bond length is 2.65 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Probing crystallographic orientation-specific carrier lifetimes in epitaxial Ge/AlAs and InGaAs/InP heterostructures

Current silicon (Si) fin transistors rely on (100) and (110) crystallographically oriented surfaces, and the proposed alternate channel transistor technology comprises materials with higher mobility than Si. Crystallographically oriented epitaxial germanium (Ge) and indium–gallium arsenide (InGaAs) have the potential to replace Si in ultra-low power transistor applications. The higher carrier lifetime is an indication of superior material quality, which relates to the leakage current of a fin transistor. To gain insights into the carrier recombination dynamics in these crystallographically oriented epitaxial Ge and InGaAs layers, the contactless microwave photoconductive decay (μ-PCD) technique at an excitation wavelength of 1500 nm was employed to probe the orientation-specific carrier lifetimes. Highly effective carrier lifetimes >200 ns for (100)Ge/AlAs and (110)Ge/AlAs, and ~80 ns for (111)Ge/AlAs heterostructures, were extracted at room temperature. The measured carrier lifetime has a strong dependence on the surface orientation, which could be related to orientation-specific bulk trap states present within the bandgap of Ge. The (111)Ge orientation has 3 times lower carrier lifetime compared to the (100)Ge and (110)Ge surface orientations. On the other hand, the carrier lifetimes of 125 μs and 10 ns were determined from (100)InGaAs/InP and (110)InGaAs/InP heterostructures, respectively. The reduction in carrier lifetimes in both (111)Ge and (110)InGaAs was due to high electrical conductivity or higher bulk trap states present within the bandgap as well as the facet-dependent growth of the (110)InGaAs layer on InP. A surface passivating layer is indispensable for these orientation-specific epitaxial layers to improve the carrier lifetime. Therefore, the higher carrier lifetimes from technologically interesting (100)Ge and (110)Ge surfaces would offer a path for the development of Ge-based ultra-low power electronics, and optoelectronic devices based on the (100)InGaAs layer.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Distributed fiber sensing systems for 3D combustion temperature field monitoring in coal-fired boilers using optically generated acoustic waves (Final Report)

In this project, we have developed and tested three kinds of fiber optic sensing systems for real time monitoring of temperature variations within an industrial scale boiler furnace. The fiber optic sensing systems target spatial and temporal distributions of high temperature profiles in a boiler furnace in fossil power plants. The reconstructed temperature profile will provide critical input for the control mechanisms to optimize the combustion process. This temperature profile will address the essential problem for fossil power plants in achieving higher efficiency and fewer pollutant emissions. Acoustic pyrometer systems have been used to reconstruct temperature field of power plant boilers based on measuring TOF (times-of-flight) of sound waves along some straight paths in a 2D cross-section of the boiler. In this project, optically generated acoustic signals from a fiber optic sensing system have replaced the acoustic signals generated from an electrical transducer. A 3D reconstruction algorithm replaced the previous 2D model. In this project, three kinds of fiber optic sensing systems have been developed and tested. They are fiber optic sensing system I, fiber optic sensing system II (Distributed Sensing System I) and fiber optic sensing system III (Distributed Sensing System II). For fiber optic sensing system I, the fiber optic ultrasound generator acts as a signal generator. A microphone, hydrophone or other electronic devices serve as a signal receiver. In this system, there are one generator and one receiver. Distance test, water temperature test, air temperature test, air temperature reconstruction, and GE ISBF pilot test were performed by Fiber optic sensing system I. The fiber optic sensing system I successfully detected temperature in all these tests. We got 2D temperature reconstruction results by using the fiber optic sensing system I and it matched the reference data. The fiber optic sensing system I successfully survived in GE ISBF boiler environment (480 °F). For fiber optic sensing system II (Distributed Sensing System I), it is an all optical ultrasound system. The fiber optic ultrasound generator acts as a signal generator. Fiber Bragg Grating (FBG) and Fabry-Perot (FP) sensor act as a signal receiver. In this system, there is one generator and one receiver. Aluminum plate temperature test, furnace high temperature test, and GE ISBF pilot test were performed by the fiber optic sensing system II. Fiber optic sensing system II successfully detected the temperature in all these tests. The fiber optic sensing system II successfully survived at up to 700 °C furnace environment and 320 °C GE ISBF boiler environment. For fiber optic sensing system III (Distributed Sensing System II), it is also an all optical ultrasound system. The fiber optic ultrasound generator acts as a signal generator. Multiple FP fiber sensors act as signal receivers. In this system, there is one generator and three receivers. Three GE ISBF pilot tests were performed by fiber optic sensing system III. The fiber optic sensing system III survived in the cold flow tests in GE’s ISBF pilot test facility. However, we didn’t get high temperature data by using this system since the nanosecond laser issues. During the period of the project, test trials, data simulation and algorithm optimization was performed successfully. For real time temperature field construction, the sampling rate must be fast enough to capture the field variations. The technology of Code-division multiple access (CDMA) is well studied which could allow parallel multiplexing, even if signals overlap in time or frequencies. Moreover, it has been known that extending the length of signal significantly improves SNR. For acoustic signals, these multiplexing techniques have also been widely used, mainly for sonar and acoustic communications. The CDMA modulation technique has been proposed and studied to guarantee high network throughput, low channel access delay and low energy consumption. We have studied the temperature field reconstruction using Gaussian Radial Basis Functions (GRBF)-based approximation approach. Reconstruction of 3D temperature field using Neural Networks with measured TOF and known propagation paths is feasible. 2D and 3D temperature field reconstruction simulation results are achieved. The milestone status is shown in Table 1. We finished milestone 1-8 and milestone 10. For milestone 9, we did three pilot tests by using the fiber optic sensing system III (Distributed Sensing System II) at GE Power. However, due to the failure of the ns laser, we did not get the temperature results. We conducted some additional tasks that were not originally proposed: 1) We fabricated a fiber optic sensing system I and did a pilot test based on this system. 2) In the proposal, we proposed two pilot tests at GE Power. In reality, we finished at least seven pilot tests at GE Power. GE Power has made a lot of efforts for supporting the pilot tests. 3) We got a simulation results based on CDMA. In summary, most of the tasks have been accomplished. The outcome of this project removed a few barriers that hinder the achievement of the final product of the distributed sensing systems. With the successful accomplishment of this project, a prototype of the fiber optic sensing system can be fabricated to attract more interests from companies and other funding agencies.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

Materials Data on TmMnGe by Materials Project

TmMnGe crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Tm is bonded in a 5-coordinate geometry to five Ge atoms. There are one shorter (2.84 Å) and four longer (2.89 Å) Tm–Ge bond lengths. Mn is bonded to four Ge atoms to form a mixture of distorted edge and corner-sharing MnGe4 tetrahedra. There are two shorter (2.55 Å) and two longer (2.72 Å) Mn–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a distorted q6 geometry to three equivalent Tm and six equivalent Mn atoms. In the second Ge site, Ge is bonded in a 9-coordinate geometry to six equivalent Tm and three equivalent Mn atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiErGe by Materials Project

LiErGe crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Li is bonded to four Ge atoms to form a mixture of distorted corner and edge-sharing LiGe4 tetrahedra. There are two shorter (2.67 Å) and two longer (2.75 Å) Li–Ge bond lengths. Er is bonded in a 5-coordinate geometry to five Ge atoms. There are four shorter (2.97 Å) and one longer (2.98 Å) Er–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to six equivalent Li and three equivalent Er atoms. In the second Ge site, Ge is bonded in a 9-coordinate geometry to three equivalent Li and six equivalent Er atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiYGe by Materials Project

LiYGe crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Li is bonded to four Ge atoms to form a mixture of distorted edge and corner-sharing LiGe4 tetrahedra. There are two shorter (2.70 Å) and two longer (2.79 Å) Li–Ge bond lengths. Y is bonded in a 5-coordinate geometry to five Ge atoms. All Y–Ge bond lengths are 3.00 Å. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to six equivalent Li and three equivalent Y atoms. In the second Ge site, Ge is bonded in a 9-coordinate geometry to three equivalent Li and six equivalent Y atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiGdGe by Materials Project

LiGdGe crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Li is bonded to four Ge atoms to form a mixture of distorted edge and corner-sharing LiGe4 tetrahedra. There are two shorter (2.72 Å) and two longer (2.81 Å) Li–Ge bond lengths. Gd is bonded in a 5-coordinate geometry to five Ge atoms. There are one shorter (3.02 Å) and four longer (3.03 Å) Gd–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to six equivalent Li and three equivalent Gd atoms. In the second Ge site, Ge is bonded in a 9-coordinate geometry to three equivalent Li and six equivalent Gd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiHoGe by Materials Project

LiHoGe crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Li is bonded to four Ge atoms to form a mixture of distorted corner and edge-sharing LiGe4 tetrahedra. There are two shorter (2.68 Å) and two longer (2.77 Å) Li–Ge bond lengths. Ho is bonded in a 5-coordinate geometry to five Ge atoms. There are one shorter (2.98 Å) and four longer (2.99 Å) Ho–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to six equivalent Li and three equivalent Ho atoms. In the second Ge site, Ge is bonded in a 9-coordinate geometry to three equivalent Li and six equivalent Ho atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiNdGe by Materials Project

LiNdGe crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Li is bonded to four Ge atoms to form a mixture of distorted edge and corner-sharing LiGe4 tetrahedra. There are two shorter (2.77 Å) and two longer (2.88 Å) Li–Ge bond lengths. Nd is bonded in a 5-coordinate geometry to five Ge atoms. There are one shorter (3.06 Å) and four longer (3.10 Å) Nd–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to six equivalent Li and three equivalent Nd atoms. In the second Ge site, Ge is bonded in a 9-coordinate geometry to three equivalent Li and six equivalent Nd atoms.

36 MATERIALS SCIENCE↗