| 461. |
- Xie, Zi Kang, et al.
(författare)
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Electron scale coherent structure as micro accelerator in the Earth's magnetosheath
- 2024
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 15:1, s. 886-
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Tidskriftsartikel (refereegranskat)abstract
- Turbulent energy dissipation is a fundamental process in plasma physics that has not been settled. It is generally believed that the turbulent energy is dissipated at electron scales leading to electron energization in magnetized plasmas. Here, we propose a micro accelerator which could transform electrons from isotropic distribution to trapped, and then to stream (Strahl) distribution. From the MMS observations of an electron-scale coherent structure in the dayside magnetosheath, we identify an electron flux enhancement region in this structure collocated with an increase of magnetic field strength, which is also closely associated with a non-zero parallel electric field. We propose a trapping model considering a field-aligned electric potential together with the mirror force. The results are consistent with the observed electron fluxes from ~50 eV to ~200 eV. It further demonstrates that bidirectional electron jets can be formed by the hourglass-like magnetic configuration of the structure.
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| 462. |
- Xu, An.Jun, et al.
(författare)
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Recycling of EAF dust by smelting in the electric arc furnace and its influences on the EAF operation and dust generation
- 2010
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Ingår i: Journal of Iron and Steel Research International. - 1006-706X .- 2210-3988. ; 17:Suppl. 2, s. 132-141
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Tidskriftsartikel (refereegranskat)abstract
- The 2(nd) campaign for recycling electric arc furnace dust (EAFD) has been carried out at Uddeholms AB (early as Uddeholm Tooling AB). Studies examining the effects of EAFD smelting on parameters related to EAF products, energy consumption and EAFD generation have been performed jointly by Uddeholms AB and MiMeR, Minerals and Metals Recycling Research Center, at Lulea University of Technology. 114 tonnes of EAFD were smelted in 121 EAF heats during the campaign. Dust samples were taken isokinetically from the exhaust gas system during the charger processing. Data of Zn contents in the dust samples were combined with other results to examine the influence of EAF operating conditions and EAFD recycling on Zn evaporation. Via EAFD recycling, Zn content in dust increased from 21.5% to 29.7% and the quantity of dust decreased by more than 40%. There were hardly any negative impact noted during the campaign on the furnace energy consumption and properties of steel and slag tapped from the EAF, while the recycled EAFD was amounted to around 2% of the steel weight
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| 463. |
- Xu, Bing, et al.
(författare)
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Clinicopathological significance of caspase-8 and caspase-10 expression in rectal cancer
- 2008
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Ingår i: Oncology. - : S. Karger AG. - 0890-9091 .- 0030-2414 .- 1423-0232. ; 74:3-4, s. 229-236
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To investigate the expression of caspase-8 and -10 in rectal adenoma, adenocarcinoma and the corresponding normal mucosa tissue, and to clarify the relationship between their expression and clinicopathological parameters of rectal cancer. Methods: The expression of caspase-8 and -10 was determined by real-time RT-PCR and immunohistochemistry in 36 rectal adenomas, 93 rectal cancers and 93 corresponding normal rectal mucosa samples. Results: Compared with normal mucosa, the mRNA expression of caspase-8 was higher in adenomas (p = 0.003), while that of caspase-10 was lower in adenomas (p = 0.035) and cancers (p = 0.001). Immunohistochemical results showed caspase-8 up-regulation in adenomas (p = 0.014), and caspase-10 down-regulation in adenomas (p = 0.034) and cancers (p < 0.001) compared with normal mucosa samples. Cancers with poor differentiation had lower caspase-10 mRNA and protein levels than those with better differentiation (p = 0.041 and p = 0.046, respectively). The protein expression of caspase-8 and -10 was in accordance with the mRNA expression (p = 0.043 and p = 0.018, respectively). Conclusions: Caspase-8 expression was up-regulated in rectal adenomas. Caspase-10 expression was down-regulated in both rectal adenomas and cancers, and was further related to differentiation. Caspase-8 and -10 may be involved in the pathogenesis of rectal cancer. Copyright © 2008 S. Karger AG.
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| 464. |
- Xu, Yan, et al.
(författare)
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Impact of Amine Additives on Perovskite Precursor Aging : A Case Study of Light-Emitting Diodes
- 2021
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Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 12:25, s. 5836-5843
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Tidskriftsartikel (refereegranskat)abstract
- Amines are widely employed as additives for improving the performance of metal halide perovskite optoelectronic devices. However, amines are well-known for their high chemical reactivity, the impact of which has yet to receive enough attention from the perovskite light-emitting diode community. Here, by investigating an unusual positive aging effect of CH3NH3I/CsI/PbI2 precursor solutions as an example, we reveal that amines gradually undergo N-formylation in perovskite precursors over time. This reaction is initialized by hydrolysis of dimethylformamide in the acidic chemical environment. Further investigations suggest that the reaction products collectively impact perovskite crystallization and eventually lead to significantly enhanced external quantum efficiency values, increasing from similar to 2% for fresh solutions to greater than or similar to 12% for aged ones. While this case study provides a positive aging effect, a negative aging effect is possible in other perovksite systems. Our findings pave the way for more reliable and reproducible device fabrication and call for further attention to underlying chemical reactions within the perovskite inks once amine additives are included.
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| 465. |
- Xue-Jian, Xu, et al.
(författare)
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Enhanced Performance and Stability in Polymer Photovoltaic Cells Using Ultraviolet-Treated PEDOT:PSS
- 2013
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Ingår i: Chinese Physics Letters. - : Institute of Physics. - 0256-307X .- 1741-3540. ; 30:7
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the effects of ultraviolet (UV) irradiation treatment with varying irradiation intensities for different treatment times of poly(3, 4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) film on the performance and stability of polymer solar cells (PSCs) based on regioregular poly(3-hexylthiophene) (P3HT) and methanofullerene [6,6]-phenyl C-61-butyric acid methyl ester (PCBM) blend. Ultraviolet-visible transmission spectra, x-ray photoelectron spectroscopy, contact angle measurement, atomic force microscopy and the Kelvin probe method are conducted to characterize the UV-treated PEDOT:PSS film. The results demonstrate that UV treatment can improve the power conversion efficiency (PCE) and stability of PSCs effectively. The best performance is achieved under 1200 mu W/cm(2) UV treatment for 50 min. Compared to the control device, the optimized device exhibits enhanced performance with a V-OC of 0.59 V, J(SC) of 12.3 mA/cm(2), fill factor of 51%, and PCE of 3.64%, increased by 3.5%, 33%, 8.7% and 50%, respectively. The stability of the PSCs is enhanced by 2.5 times simply through the UV treatment on the PEDOT:PSS buffer layer. The improvement in the device performance and stability is attributed to the improvement in the wettability property and the increase in the work function of the PEDOT:PSS film by UV treatment, while the impact of UV treatment on the transparency of the PEDOT:PSS film is negligible. The strategy of using UV treatment to improve device performance and stability is attractive due to its simplicity, cost-effectiveness, and because it is suitable for large-scale commercial production.
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| 466. |
- Yang, Biao, et al.
(författare)
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Synthesis of Surface Covalent Organic Frameworks via Dimerization and Cyclotrimerization of Acetyls
- 2015
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society. - 0002-7863 .- 1520-5126. ; 137:15, s. 4904-4907
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Tidskriftsartikel (refereegranskat)abstract
- The formation of additional phenyl rings on surfaces is of particular interest because it allows for the building-up of surface covalent organic frameworks. In this work, we show for the first time that the cyclotrimerization of acetyls to aromatics provides a promising approach to 2D conjugated covalent networks on surfaces under ultrahigh vacuum. With the aid of scanning tunneling microscopy, we have systematically studied the reaction pathways and the products. With the combination of density functional theory calculations and X-ray photoemission spectroscopy, the surface-assisted reaction mechanism, which is different from that in solution, was explored.
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| 467. |
- Yang, Dong, et al.
(författare)
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Safe-WirelessHART: A Novel Framework Enabling Safety-Critical Applications Over Industrial WSNs
- 2018
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Ingår i: IEEE Transactions on Industrial Informatics. - 1551-3203 .- 1941-0050. ; 14:8, s. 3513-3523
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Tidskriftsartikel (refereegranskat)abstract
- Industrial wireless sensor networks (IWSNs) have mainly been used to monitor applications, but recently an interest in control and safety applications has emerged. Functional safety and communication in open transmission systems have been laid down in the IEC 61784-3-3 standard. The standard is based on a cyclic polling mechanism, which consumes a considerable amount of bandwidth; since existing IWSNs are very resource-constrained, this becomes a major challenge. To overcome this problem, this paper proposes a novel framework that uses an event-triggered failsafe mechanism based on synchronous wired polling and wireless time-slotted time division multiple access. We analytically derive the minimum and maximum bound for the most important metric for safety-critical applications, safety function response time (SFRT). A new metric, normal state interrupt time (NSIT), is proposed in this paper. Furthermore, we also implement the proposed framework by using the WirelessHART standard. The results are compared to the classical time-triggered approach used in the IEC 61784-3-3 standard. The obtained results show that the proposed framework can reduce the bandwidth usage by 90% and support safety-critical applications that require a SFRT less or equal to 150 ms.
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| 468. |
- Yang, Fu-Sheng, et al.
(författare)
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Chromosome-level genome assembly of a parent species of widely cultivated azaleas
- 2020
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Azaleas (Ericaceae) comprise one of the most diverse ornamental plants, renowned for their cultural and economic importance. We present a chromosome-scale genome assembly for Rhododendron simsii, the primary ancestor of azalea cultivars. Genome analyses unveil the remnants of an ancient whole-genome duplication preceding the radiation of most Ericaceae, likely contributing to the genomic architecture of flowering time. Small-scale gene duplications contribute to the expansion of gene families involved in azalea pigment biosynthesis. We reconstruct entire metabolic pathways for anthocyanins and carotenoids and their potential regulatory networks by detailed analysis of time-ordered gene co-expression networks. MYB, bHLH, and WD40 transcription factors may collectively regulate anthocyanin accumulation in R. simsii, particularly at the initial stages of flower coloration, and with WRKY transcription factors controlling progressive flower coloring at later stages. This work provides a cornerstone for understanding the underlying genetics governing flower timing and coloration and could accelerate selective breeding in azalea. Azaleas are one of the most diverse ornamental plants and have cultural and economic importance. Here, the authors report a chromosome-scale genome assembly for the primary ancestor of the azalea cultivar Rhododendro simsi and identify transcription factors that may function in flower coloration at different stages.
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| 469. |
- Yang, Geng, et al.
(författare)
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A 1.0 V 78 uW reconfigurable ASIC embedded in an intelligent electrode for continuous remote ECG applications
- 2009
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Ingår i: EMBC. ; , s. 2316-2319
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Konferensbidrag (refereegranskat)abstract
- In this paper, a reconfigurable, low-power Application Specific Integrated Circuit (ASIC) that extracts and transmits electrocardiograph (ECG) signals is presented. An intelligent electrode is introduced which consists of the proposed ASIC and a micro spike array, permitting onsite ECG signal acquisition, processing and transmission. Fabricated in a standard 0.18 mum CMOS process, the ASIC consumes 78 muW with 1.0 V core voltage at 6 MHz operating frequency and only occupies 2.25 mm2. The tiny silicon size makes it possible and suitable to embed the proposed ASIC into an intelligent electrode, and the low power consumption makes it feasible for long term continuous ECG monitoring.
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| 470. |
- Yang, Geng, 1980-, et al.
(författare)
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A Hybrid Low Power Biopatch for Body Surface Potential Measurement
- 2013
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Ingår i: IEEE Journal of Biomedical and Health Informatics. - : IEEE Computer Society. - 2168-2194. ; 17:3, s. 591-599
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a wearable biopatch prototype for body surface potential measurement. It combines three key technologies, including mixed-signal system on chip (SoC) technology, inkjet printing technology, and anisotropic conductive adhesive (ACA) bonding technology. An integral part of the biopatch is a low-power low-noise SoC. The SoC contains a tunable analog front end, a successive approximation register analog-to-digital converter, and a reconfigurable digital controller. The electrodes, interconnections, and interposer are implemented by inkjet-printing the silver ink precisely on a flexible substrate. The reliability of printed traces is evaluated by static bending tests. ACA is used to attach the SoC to the printed structures and form the flexible hybrid system. The biopatch prototype is light and thin with a physical size of 16 cm x 16 cm. Measurement results show that low-noise concurrent electrocardiogram signals from eight chest points have been successfully recorded using the implemented biopatch.
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