| 1. |
- Xiong, Wei, et al.
(författare)
-
Thermodynamic reassessment of the Cu-Mg-Ni system with brief comments on the thermodynamic modeling of the sub-systems
- 2008
-
Ingår i: Calphad. - : Elsevier BV. - 0364-5916 .- 1873-2984. ; 32:4, s. 675-685
-
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.
|
|
| 2. |
|
|
| 3. |
- Ai, Yue-Jie, 1982-, et al.
(författare)
-
Repair of DNA Dewar Photoproduct to (6-4) photoproduct in (6-4) Photolyase
- 2011
-
Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 115:37, s. 10976-10982
-
Tidskriftsartikel (refereegranskat)abstract
- Dewar photoproduct (Dewar PP) is the valence isomer of (6-4) photoproduct ((6-4)PP) in photodamaged DNA. Compared to the extensive studied CPD photoproducts, the underlying repair mechanisms for the (6-4)PP, and especially for the Dewar PP, are not well-established to date. In this paper, the repair mechanism of DNA Dewar photoproduct T(dew)C in (6-4) photolyase was elucidated using hybrid density functional theory. Our results showed that, during the repair process, the T(dew)C has to isomerize to T(6-4)C photolesion first via direct C6'-N3' bond cleavage facilitated by electron injection. This isomerization mechanism is energetically much more efficient than other possible rearrangement pathways. The calculations provide a theoretical interpretation to recent experimental observations.
|
|
| 4. |
- Cao, Lina, et al.
(författare)
-
Atomically dispersed iron hydroxide anchored on Pt for preferential oxidation of CO in H-2
- 2019
-
Ingår i: Nature. - : NATURE PUBLISHING GROUP. - 0028-0836 .- 1476-4687. ; 565:7741, s. 631-635
-
Tidskriftsartikel (refereegranskat)abstract
- Proton-exchange-membrane fuel cells (PEMFCs) are attractive next-generation power sources for use in vehicles and other applications(1), with development efforts focusing on improving the catalyst system of the fuel cell. One problem is catalyst poisoning by impurity gases such as carbon monoxide (CO), which typically comprises about one per cent of hydrogen fuel(2-4). A possible solution is on-board hydrogen purification, which involves preferential oxidation of CO in hydrogen (PROX)(3-7). However, this approach is challenging(8-15) because the catalyst needs to be active and selective towards CO oxidation over a broad range of low temperatures so that CO is efficiently removed (to below 50 parts per million) during continuous PEMFC operation (at about 353 kelvin) and, in the case of automotive fuel cells, during frequent cold-start periods. Here we show that atomically dispersed iron hydroxide, selectively deposited on silica-supported platinum (Pt) nanoparticles, enables complete and 100 per cent selective CO removal through the PROX reaction over the broad temperature range of 198 to 380 kelvin. We find that the mass-specific activity of this system is about 30 times higher than that of more conventional catalysts consisting of Pt on iron oxide supports. In situ X-ray absorption fine-structure measurements reveal that most of the iron hydroxide exists as Fe-1(OH)(x) clusters anchored on the Pt nanoparticles, with density functional theory calculations indicating that Fe-1(OH)(x)-Pt single interfacial sites can readily react with CO and facilitate oxygen activation. These findings suggest that in addition to strategies that target oxide-supported precious-metal nanoparticles or isolated metal atoms, the deposition of isolated transition-metal complexes offers new ways of designing highly active metal catalysts.
|
|
| 5. |
- Fan, Wei, et al.
(författare)
-
A machining accuracy informed adaptive positioning method for finish machining of assembly interfaces of large-scale aircraft components
- 2021
-
Ingår i: Robotics and Computer-Integrated Manufacturing. - : Elsevier BV. - 0736-5845 .- 1879-2537. ; 67
-
Tidskriftsartikel (refereegranskat)abstract
- An assembly interface of a large-scale aircraft component is a joint surface to connect adjacent large components. To guarantee the final assembly accuracy of the large components, the assembly interface is finish machined on site before the final assembly to cut the observed machining allowance. Thus, aiming at realizing the high efficiency and high quality in the finish machining operation, in this paper we propose an adaptive positioning method that integrates comprehensive engineering constrains (including Positioning Accuracy Constraints (PACs) of the large component and Machining Accuracy Constraints (MACs) of the assembly interface). In this method, the key Measurement Points (MPs) of a component are assigned to obtain its initial pose. Then the measurement data and the initial pose are used as input data to obtain the optimal pose parameters of the component based on an improved Particle Swarm Optimization Simulated Annealing (PSO-SA) algorithm. The optimal pose parameters can provide data support for the adaptive positioning of the large component, the function of which is implemented based on IEC 61499 Function Block (FB) technology. Finally, a positioning experiment of a vertical tail of a large passenger aircraft is used to validate the proposed method. The experimental results illustrate that the proposed method can improve the efficiency and positioning accuracy of the large component, compared to the traditional method.
|
|
| 6. |
- Han, L., et al.
(författare)
-
Cell transcriptomic atlas of the non-human primate Macaca fascicularis
- 2022
-
Ingår i: Nature. - : Springer Nature. - 0028-0836 .- 1476-4687. ; 604:7907, s. 723-731
-
Tidskriftsartikel (refereegranskat)abstract
- Studying tissue composition and function in non-human primates (NHPs) is crucial to understand the nature of our own species. Here we present a large-scale cell transcriptomic atlas that encompasses over 1 million cells from 45 tissues of the adult NHP Macaca fascicularis. This dataset provides a vast annotated resource to study a species phylogenetically close to humans. To demonstrate the utility of the atlas, we have reconstructed the cell–cell interaction networks that drive Wnt signalling across the body, mapped the distribution of receptors and co-receptors for viruses causing human infectious diseases, and intersected our data with human genetic disease orthologues to establish potential clinical associations. Our M. fascicularis cell atlas constitutes an essential reference for future studies in humans and NHPs.
|
|
| 7. |
- Huang, Zi-Nan, et al.
(författare)
-
Analysis of the stress field in the reactor vessel of the China Initiative Accelerator Driven System during postulated ULOF and UTOP transients
- 2023
-
Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549 .- 1873-2100. ; 194
-
Tidskriftsartikel (refereegranskat)abstract
- The China Initiative Accelerator Driven System (CiADS) was proposed by China Academy of Science since 2015. The subcritical reactor in CiADS is a liquid Lead Bismuth Eutectic (LBE) cooled fast reactor. When the reactor core is in operation, the LBE coolant will directly contact and corrode the inner surface of reactor vessel. Due to the high temperature, the corrosion will be more severe. If the stress on the reactor vessel exceeds the limit, the plastic deformation will occur, leading to the generation and expansion of defects and cracks, and the safety of the reactor will be affected. Therefore, evaluating the stress field of the reactor vessel under different operating conditions is a very important research project. In this paper, the finite element analysis software ADINA was applied to analyze the reactor vessel in CiADS, and the ASME Code was used as stress assessment standards. We can preliminarily prove that the stress assessments of the vessel during the postulated Unprotected Loss of Flow (ULOF) accidents satisfy the requirements of ASME Code. The limit reactivity insertion to protect the vessel from plastic deformation is 0.58$ in the postulated Unprotected Transient over Power (UTOP) accidents based on our current results. Therefore, we can preliminarily conclude that the current material selection and structural design of the reactor vessel in CiADS could survive most of the postulated transient accidents considering the stress effect.
|
|
| 8. |
- Jia, Shi, et al.
(författare)
-
2 x 300 Gbit/s Line Rate PS-64QAM-OFDM THz Photonic-Wireless Transmission
- 2020
-
Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 38:17, s. 4715-4721
-
Tidskriftsartikel (refereegranskat)abstract
- The proliferation of wireless broadband services have significantly raised the demand for high data rates. Due to the limited bandwidth of radio frequency (RF) bands that are currently in use for communication purposes, the choice of the 'Terahertz (THz) frequency region' (0.3-10 THz) is getting favored thanks to its merits of bringing together wireless and optical communications with photonics technologies. We report on an experimental demonstration of a hybrid THz photonic-wireless transmission based on a THz orthogonal polarization dual-antenna scheme. Probabilistic shaped 64-ary quadrature amplitude modulation based orthogonal frequency division multiplexing (64QAM-OFDM) modulation format is used to realize high transmission rate. A potential total system throughput of 612.65 Gbit/s (around 2 x 300 Gbit/s line rate) with an average net spectral efficiency of 4.445 bit/s/Hz per antenna is successfully achieved.
|
|
| 9. |
|
|
| 10. |
- Qiao, Mengyao, et al.
(författare)
-
60 Gbit/s PAM-4 wireless transmission in the 310 GHz band with nonlinearity tolerant signal processing
- 2021
-
Ingår i: Optics Communications. - : Elsevier BV. - 0030-4018 .- 1873-0310. ; 492
-
Tidskriftsartikel (refereegranskat)abstract
- We experimentally demonstrate a terahertz (THz) photonic wireless transmission system in the 310 GHz band with four-level pulse amplitude modulation (PAM-4) signals. A zero-bias diode is used as a simple direct detection receiver, which is cost-effective compared to a conventional coherent receiver. Moreover, we comprehensively investigate the system performance by applying linear and nonlinear equalization schemes. The experimental results show that Volterra nonlinear filtering can significantly improve the system capacity by around 90%, and transmissions of up to 60 Gbit/s PAM-4 signals over a 3 m wireless link are successfully achieved. The advantageous features of this make it promising for high-speed THz wireless communications.
|
|
