| 1. |
- Xiong, Wei, et al.
(författare)
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Thermodynamic reassessment of the Cu-Mg-Ni system with brief comments on the thermodynamic modeling of the sub-systems
- 2008
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Ingår i: Calphad. - : Elsevier BV. - 0364-5916 .- 1873-2984. ; 32:4, s. 675-685
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Tidskriftsartikel (refereegranskat)abstract
- The Cu-Mg-Ni system was reassessed using the CALPHAD (CALculation of PHAse Diagram) approach, in order to provide a reliable thermodynamic description. A set of self-consistent thermodynamic parameters for the Cu-Mg-Ni system was obtained. The liquidus projection and the reaction scheme were generated by using the present thermodynamic parameters. Significant improvements have been made, compared with the previous assessments. Thermodynamic modeling for the three sub-systems was briefly reviewed. Further work is of interest to refine the thermodynamic description of the binary systems, in order to avoid the appearance of the artificial phase equilibria in liquid above 2500 degrees C.
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| 2. |
- Zhang, Wei-Wei, et al.
(författare)
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Phase equilibria of the Fe-Ni-Si system at 850 degrees C
- 2009
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 481:1-2, s. 509-514
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Tidskriftsartikel (refereegranskat)abstract
- By means of X-ray diffraction, metallography, scanning electron microscopy with energy dispersive Xray analysis, and electron probe microanalysis, the constitution of the ternary Fe-Ni-Si system at 850 degrees C over the entire composition range was established with 24 alloys. Ten of the three-phase equilibria were well determined at 850 degrees C. The existence of the ternary compound Fe5Ni3Si2 (tau(1)) with a cubic crystal structure at 850 degrees C is confirmed. The homogeneity ranges were measured and the lattice parameters were determined for most observed phases.
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| 3. |
- Zhang, Wei-Wei, et al.
(författare)
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Thermodynamic Assessment of the Cu-B System Supported by Key Experiment and First-Principles Calculations
- 2009
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Ingår i: Journal of Phase Equilibria and Diffusion. - : Springer Science and Business Media LLC. - 1547-7037 .- 1863-7345. ; 30:5, s. 480-486
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Tidskriftsartikel (refereegranskat)abstract
- The Cu-B system was investigated via a hybrid approach of key experiment and thermodynamic modeling. Based on the critically assessed Cu-B phase diagram, seven crucial alloys were selected and prepared by arc melting the pure elements. An inductively coupled plasma-atomic emission spectrometric analysis was conducted to determine the compositions of the prepared alloys. The phase equilibria were determined by using x-ray diffraction, electron probe microanalysis, and differential thermal analysis. The temperature associated with the eutectic reaction, L double left right arrow (B) + (Cu); was measured to be 1028 +/- 2 degrees C. First-principles calculations indicate that the energy of inserting a B atom into the interstitial vacancy (Va) site of the lattice for Cu atoms is marginally lower than that of substituting for a Cu atom with a B atom. Consequently, the sublattice model (Cu)(B, Va) in which B atoms occupy the interstitial sites was employed for the fcc (Cu) phase rather than the model (Cu, B)(Va) in which B atoms substitute for Cu atoms. A thermodynamic modeling of the Cu-B system was then performed by considering the reliable literature data and the present experimental results. A good agreement between modeling and experiment was obtained.
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| 4. |
- Chen, Tingjie, et al.
(författare)
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Hybrid composites of polyvinyl alcohol (PVA)/Si-Al for improving the properties of ultra-low density fiberboard (ULDF)
- 2016
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 6:25, s. 20706-20712
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Tidskriftsartikel (refereegranskat)abstract
- The hybrid composites of polyvinyl alcohol (PVA)/Si-Al were synthesized to improve the thermostability and mechanical properties of ultra-low density fiberboard (ULDF). Their physical and chemical properties were tested by using scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffractometry, thermogravimetric analysis (TGA), and a microcomputer control electronic universal testing machine. Microstructure results indicated that the distribution of inorganic fillers on the surface of ULDF was improved by the PVA. Analysis of chemical bonds and crystallinity of materials showed that part of the PVA reacted with Si-Al sol, and the other was physically crosslinked in the composite. The thermostability of ULDF decreased with the increasing content of PVA, but the mechanical properties increased. Combined with the TGA and mechanical properties results, a reasonable content of PVA (30%) was obtained. Under this condition, the modulus of rupture, modulus of elasticity, and the internal bond strength of ULDF were 0.35, 24.86, and 0.038 MPa, respectively
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| 5. |
- Chen, Tingjie, et al.
(författare)
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Optimizing Refining Conditions of Pinus massoniana Cellulose Fibers for Improving the Mechanical Properties of Ultra-Low Density Plant Fiber Composite (ULD_UFC)
- 2017
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Ingår i: BioResources. - : North Carolina State University. - 1930-2126. ; 12:1, s. 8-18
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Tidskriftsartikel (refereegranskat)abstract
- Response surface methodology was used to optimize the refining conditions of Pinus massoniana cellulose fiber and to improve the mechanical properties of ultra-low density plant fiber composite (ULD_PFC). The effects and interactions of the pulp consistency (X1), the number of passes (X2), and the beating gap (X3) on the internal bond strength of ULD_PFC were investigated. The results showed that the optimum internal bond strength (91.72 ± 2.28 kPa) was obtained under the conditions of 8.0% pulp consistency, two passes through the refiner, and a 30.0 μm beating gap. Analysis of the physical properties of the fibers and handsheets showed that the fibrillation of fibers with optimum refining conditions was improved. Also, the tear index of the optimal specimen was 13.9% and 24.5% higher than specimen-1 with a lowest beating degree of 24 oSR and specimen-6 with a highest beating degree of 73 oSR, respectively. Consequently, the optimal refining conditions of the fibers are valid for preparing ULD_PFCs.
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| 6. |
- Fang, Wei, et al.
(författare)
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Distributed cognition based localization for AR-aided collaborative assembly in industrial environments
- 2022
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Ingår i: Robotics and Computer-Integrated Manufacturing. - : Elsevier BV. - 0736-5845 .- 1879-2537. ; 75
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Tidskriftsartikel (refereegranskat)abstract
- The existing (augmented reality) AR-aided assembly is highly associated with AR devices, which mainly provides guidance for one operator, and it is hard to share augmented assembly instructions for large-scale products which require multiple operators working together. To address this problem, the paper proposes a distributed cognition based localization method for AR-aided collaborative assembly. Firstly, a scene cognition using multi-view acquisition about industrial environments is performed with incremental modeling in advance, providing the foundation for the subsequent pose estimate of multi-AR clients. Then, based on feature extracting and matching against the pre-built shop floor model, a pose recovery of AR-aided system is derived from different views of AR operators in a global coordinate system, followed by a distributed motion tracking with the complementary features of visual and inertial data, resulting in a co-located collaborative AR instruction for assembly. Finally, experiments are carried out to validate the proposed method, and experimental results illustrate that the proposed method can achieve distributed cognition-based localization accurately and robustly. Therefore, shared visual communications among multiple operators are synchronized, and assembly status is aware by all the operators.
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| 7. |
- Wei, Zhu, et al.
(författare)
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Injectable and assembled 3D solid structure for free-to-fixed shape in bone reconstruction
- 2020
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Ingår i: Applied Materials Today. - : Elsevier BV. - 2352-9407. ; 21
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Tidskriftsartikel (refereegranskat)abstract
- There is a gap between injectable and scaffold-like bioceramics. Injectable bioactive materials, such as bone cement and hydrogel, are good for minimized surgery, but the extremely low porosity and small pore size limited enhanced bone repair and regeneration. Macroporous bioceramic scaffolds are used because of the controlled pore size and porosity, but not injectable. It's a challenge of preparation of an injectable macroporous ceramic scaffold for minimized bone reconstruction. By using the reversible setting reaction of calcium sulfate and combining a dual setting system with magnesium silicate hydrate, the injectable and assembled 3D porous bioceramic scaffold has been successfully developed. The content of amorphous magnesium silicate hydrate in the dual setting system affected the mechanical strength and degradation. The porous structure could be controlled by the size of granules. The granules can also be used for the fabrication of porous materials with varied shapes and customized structures by using a simple injection process. The biological testing showed good biocompatibility and in vitro osteogenesis. By using the femoral lateral condyle defect model, we can see the granules could be injected into the defect and formed a rigid porous structure in situ, and further presented better new bone formation compared with autologous bone chips. Briefly, we demonstrated the first injectable 3D solid porous ceramic structure for minimized bone repair and free-form shaping.
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| 8. |
- Yu, Qiang, et al.
(författare)
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Unveiling segregation-induced evolution in phase constitution of Cu-containing high-entropy alloys
- 2020
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 843
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Tidskriftsartikel (refereegranskat)abstract
- A theoretical investigation of Cu segregation effect on phase constitution, magnetic, and mechanical properties of FeCoNi(CumAl)(x) high-entropy alloys is presented. Results show that the homogenous FeCoNi(Cu1.0Al)(x) only exists as a single face-centered cubic phase at arbitrary temperatures. The level of Cu-segregation determines the phase evolution amongst inhomogeneous single phase (0.75 <= m < 1.0), duplex phase (m << 0.75), and triple phase (m approximate to 0.75). Our results reproduce the observation. Only face-centered cubic phase can be formed for FeCoNi(CumAl)(x) with either rather low or extreme high content of (CumAl) even though the segregation occurred. The Cu addition lifts the total magnetic moments by enhancing the local magnetic moment of Fe, Co and Ni. The serious Cu segregation in the duplex-phase HEAs induces the decrease of ductility of fcc and bcc phases. The increasing Cu enhances the strength of Cu-rich fcc phase and the decreasing Cu weakens that of Cu-poor bcc phase.
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| 9. |
- Chen, Junsong, et al.
(författare)
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Inference Method for Residual Stress Field of Titanium Alloy Parts Based on Latent Gaussian Process Introducing Theoretical Prior
- 2024
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Ingår i: Transactions of Nanjing University of Aeronautics and Astronautics. - : Nanjing University of Aeronautics an Astronautics. - 1005-1120. ; 41:2, s. 135-146
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Tidskriftsartikel (refereegranskat)abstract
- Residual stress (RS) within titanium alloy structural components is the primary factor contributing to machining deformation. It comprises initial residual stress （IRS） and machined surface residual stress (MSRS), resulting from the interplay between IRS and high-level machining-induced residual stress MIRS). Machining deformation of components poses a significant challenge in the aerospace industry，and accurately assessing RS is crucial for precise prediction and control. However, current RS prediction methods struggle to account for various uncertainties in the component manufacturing process，leading to limited prediction accuracy. Furthermore, existing measurement methods can only gauge local RS in samples，which proves inefficient and unreliable for measuring RS fields in large components. Addressing these challenges, this paper introduces a method for simultaneously estimating IRS and MSRS within titanium alloy aircraft components using a Bayesian framework. This approach treats IRS and MSRS as unobservable fields modeled by Gaussian processes. It leverages observable deformation force data to estimate IRS and MSRS while incorporating prior correlations between MSRS fields. In this context，the prior correlation between MSRS fields is represented as a latent Gaussian process with a shared covariance function. The proposed method offers an effective means of estimating the RS field using deformation force data from a probabilistic perspective. It serves as a dependable foundation for optimizing subsequent deformation control strategies.
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| 10. |
- Li, Zhaojun, 1989, et al.
(författare)
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9.0% power conversion efficiency from ternary all-polymer solar cells
- 2017
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Ingår i: Energy and Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 10:10, s. 2212-2221
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Tidskriftsartikel (refereegranskat)abstract
- Integration of a third component into a single-junction polymer solar cell (PSC) is regarded as an attractive strategy to enhance the performance of PSCs. Although binary all-polymer solar cells (all-PSCs) have recently emerged with compelling power conversion efficiencies (PCEs), the PCEs of ternary all-PSCs still lag behind those of the state-of-the-art binary all-PSCs, and the advantages of ternary systems are not fully exploited. In this work, we realize high-performance ternary all-PSCs with record-breaking PCEs of 9% and high fill factors (FF) of over 0.7 for both conventional and inverted devices. The improved photovoltaic performance benefits from the synergistic effects of extended absorption, more efficient charge generation, optimal polymer orientations and suppressed recombination losses compared to the binary all-PSCs, as evidenced by a set of experimental techniques. The results provide new insights for developing high-performance ternary all-PSCs by choosing appropriate donor and acceptor polymers to overcome limitations in absorption, by affording good miscibility, and by benefiting from charge and energy transfer mechanisms for efficient charge generation.
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