| 61. |
- Zhu, Z, et al.
(författare)
-
Vapor-solid-solid grown Ge nanowires at integrated circuit compatible temperature by molecular beam epitaxy
- 2017
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 122:9, s. 94304-
-
Tidskriftsartikel (refereegranskat)abstract
- We demonstrate Au-assisted vapor-solid-solid (VSS) growth of Ge nanowires (NWs) by molecular beam epitaxy at the substrate temperature of similar to 180 degrees C, which is compatible with the temperature window for Si-based integrated circuit. Low temperature grown Ge NWs hold a smaller size, similar uniformity, and better fit with Au tips in diameter, in contrast to Ge NWs grown at around or above the eutectic temperature of Au-Ge alloy in the vapor-liquid-solid (VLS) growth. Six growth orientations were observed on Ge (110) by the VSS growth at similar to 180 degrees C, differing from only one vertical growth direction of Ge NWs by the VLS growth at a high temperature. The evolution of NWs dimension and morphology from the VLS growth to the VSS growth is qualitatively explained by analyzing the mechanism of the two growth modes.
|
|
| 62. |
|
|
| 63. |
|
|
| 64. |
|
|
| 65. |
- Gubicza, J., et al.
(författare)
-
Evolution of microstructure and hardness in Hf 25 Nb 25 Ti 25 Zr 25 high-entropy alloy during high-pressure torsion
- 2019
-
Ingår i: Journal of Alloys and Compounds. - : Elsevier. - 0925-8388 .- 1873-4669. ; 788, s. 318-328
-
Tidskriftsartikel (refereegranskat)abstract
- A four-component equimolar high-entropy alloy (HEA) with the composition of HfNbTiZr and body-centered cubic (bcc) structure was processed by HPT at RT. The evolution of the dislocation density, the grain size and the hardness was monitored along the HPT-processed disk radius for different numbers of turns between ¼ and 20. It was found that most of the increase of the dislocation density and the refinement of the grain structure occurred up to the shear strain of ∼40. Between the strains of ∼40 and ∼700, only a slight grain size reduction was observed. The saturated dislocation density and grain size were ∼2.1 × 10 16 m −2 and ∼30 nm, respectively. The saturation in hardness was obtained at ∼4450 MPa. These values were similar to the parameters determined in the literature for five-component HEAs processed by HPT. The analysis confirmed that the main component in the strength was given by the friction stress in the HPT-processed bcc HfNbTiZr HEA. It was also revealed that the contribution of the high dislocation density to the strength was significantly higher than the effect of the small grain size.
|
|
| 66. |
- Hadjiev, V. G., et al.
(författare)
-
Symmetry of phonon, magnetic, and spin-phonon excitations in GdSr2RuCu2O8 single crystals
- 2001
-
Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 64
-
Tidskriftsartikel (refereegranskat)abstract
- We present a polarized Raman scattering study of GdSr2RuCu2O8 single crystals. In this compound, the RuO6 octahedra are rotated around the c axis that in turn gives some Raman activity of the oxygen (O-Ru) vibrations at 265 cm(-1) (A(1g)), 411 cm(-1) (B-2g) and 607 cm(-1) (B-1g). These vibrations, as well as those of the apical oxygen of RuO6, at 654 cm(-1) (A(1g)) and the Cu-plane oxygen at 318 cm(-1) (B-2g), clearly respond to the onset of magnetic ordering at T-m approximate to 140 K. In particular, the 265 cm(-1) mode hardens anomalously with decreasing temperature below T-m. Notably, the corresponding phonon line is absent in the Raman spectra of GdSr2NbCu2O8 (Nb5+:4d(0)), a compound isomorphic to GdSr2RuCu2O8 (Ru5+:4d(3)). We argue that the eigenvector of the 265 cm(-1) phonon (rotational mode) facilitates efficient modulation of the Ru(t(1g))-O-Ru (p) bands. This modulation gives both Raman scattering strength to the 265 cm(-1) mode and strong spin-phonon coupling.
|
|
| 67. |
- He, W., et al.
(författare)
-
Deep learning-assisted flexible piezoresistive sensor with liquid-phase reduced metal electrodes for fitness movement recognition and correction
- 2024
-
Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 495
-
Tidskriftsartikel (refereegranskat)abstract
- Flexibility and wearability in electronic devices gain prominence with the rise of national fitness campaigns. Among them, piezoresistive sensors stand out for their ability to accurately monitor health signals due to their high sensitivity. However, conventional metal nanoparticle ink electrodes face issues like peeling, chemical instability, and substrate limitations. This study introduces a novel method for fabricating high-performance flexible piezoresistive sensors using liquid-phase reduced metal electrodes. Integration of porous polydimethylsiloxane (PDMS) substrates with highly conductive interdigital silver electrodes (1.6 × 10−6 Ω·m) addresses conventional electrode shortcomings, offering permeability, flexibility, and outstanding conductivity. Incorporation of a graphene (GR)/carbon nanotube (CNT)/Ecoflex composite enhances sensor piezoresistive sensing capabilities, with features including high sensitivity (3.57 KPa−1), rapid response time (58 ms/72 ms), and excellent cycle stability (>10000 cycles). The sensor finds utility in various applications, including human physiological signal monitoring, pressure array recognition, and handwriting recognition. Additionally, with deep learning techniques, the system achieves accurate recognition (99.25 %) and correction (98.75 %) of diverse fitness movements, aiming to promote safer exercise practices, enhance training efficiency, and advance intelligent wearable fitness devices.
|
|
| 68. |
- He, YQ, et al.
(författare)
-
A polygenic risk score for nasopharyngeal carcinoma shows potential for risk stratification and personalized screening
- 2022
-
Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 13:1, s. 1966-
-
Tidskriftsartikel (refereegranskat)abstract
- Polygenic risk scores (PRS) have the potential to identify individuals at risk of diseases, optimizing treatment, and predicting survival outcomes. Here, we construct and validate a genome-wide association study (GWAS) derived PRS for nasopharyngeal carcinoma (NPC), using a multi-center study of six populations (6 059 NPC cases and 7 582 controls), and evaluate its utility in a nested case-control study. We show that the PRS enables effective identification of NPC high-risk individuals (AUC = 0.65) and improves the risk prediction with the PRS incremental deciles in each population (Ptrend ranging from 2.79 × 10−7 to 4.79 × 10−44). By incorporating the PRS into EBV-serology-based NPC screening, the test’s positive predictive value (PPV) is increased from an average of 4.84% to 8.38% and 11.91% in the top 10% and 5% PRS, respectively. In summary, the GWAS-derived PRS, together with the EBV test, significantly improves NPC risk stratification and informs personalized screening.
|
|
| 69. |
|
|
| 70. |
- Huang, D., et al.
(författare)
-
Electronic structure, defect properties, and optimization of the band gap of the earth-abundant and low-toxicity photovoltaic absorber Cu3SbS4
- 2022
-
Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 24:41, s. 25258-25269
-
Tidskriftsartikel (refereegranskat)abstract
- Searching for an earth-abundant and environment-friendly absorber for thin-film solar cells that provides similar power conversion efficiency to CdTe and Cu(In,Ga)Se2 is of great importance for large-scale applications. Success would change the world's solar energy supply to an even more sustainable material resource. In this paper, we have studied by first-principles calculations the electronic structure and defect properties of the promising absorber Cu3SbS4. Its electronic properties, like direct band gap, high absorption coefficient, and light carrier effective masses, satisfy the requirements for an absorber except for its somewhat too small band gap energy. Sulfur and copper vacancies are easily formed defects in Cu3SbS4, where the S vacancy shrinks the band gap and degrades the material. This probably explains the experimental findings of a rather poor device performance. The suitable preparation conditions for Cu3SbS4 as an absorber are anticipated to be Cu-poor, Sb-moderate, and S-rich conditions. Herein, isovalent element alloying is demonstrated to be an effective way to increase the gap energy and thereby improve the material properties.
|
|
