| 1. |
- Ablikim, M., et al.
(författare)
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First measurement of e(+)e(-) -> pK(S)(0)(n)over-barK(-) + c.c. above open charm threshold
- 2018
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 98:3
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Tidskriftsartikel (refereegranskat)abstract
- The process e(+)e(-) -> pK(S)(0)(n) over barK(-) + c.c. and its intermediate processes are studied for the first time, using data samples collected with the BESIII detector at BEPCII at center-of-mass energies of 3.773, 4.008, 4.226, 4.258, 4.358, 4.416, and 4.600 GeV, with a total integrated luminosity of 7.4 fb(-1). The Born cross section of e(+)e(-) -> pK(S)(0)(n) over barK(-) + c.c. is measured at each center-of-mass energy, but no significant resonant structure in the measured cross-section line shape between 3.773 and 4.600 GeV is observed. No evident structure is detected in the pK(-), nK(S)(0), pK(S)(0), nK(+), p (n) over bar, or (KSK-)-K-0 invariant mass distributions except for Lambda(1520). The Born cross sections of e(+)e(-) -> Lambda(1520)(n) over barK(S)(0) + c.c. and e(+)e(-) -> Lambda(1520)(p) over barK(+) + c.c. are measured, and the 90% confidence level upper limits on the Born cross sections of e(+)e(-) -> Lambda(1520)(Lambda) over bar (1520) are determined at the seven center-of-mass energies. There is an evident difference in line shape and magnitude of the measured cross sections between e(+)e(-) -> Lambda(1520)(-> pK(-))(n) over barK(S)(0) and e(+)e(-) -> pK-(Lambda) over bar (1520)(-> (n) over barK(S)(0)).
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| 2. |
- Ablikim, M., et al.
(författare)
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Observation of psi(3686) -> eta ' e(+)e(-)
- 2018
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Ingår i: Physics Letters B. - : ELSEVIER SCIENCE BV. - 0370-2693 .- 1873-2445. ; 783, s. 452-458
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Tidskriftsartikel (refereegranskat)abstract
- Using a data sample of 448.1 x 10(6) psi(3686) events collected with the BESIII detector at the BEPCII collider, we report the first observation of the electromagnetic Dalitz decay psi(3686) -> eta'e(+)e(-), with significances of 7.0 sigma and 6.3 sigma when reconstructing the eta' meson via its decay modes eta' -> gamma pi(+)pi(-) and eta' -> pi(+)pi(-) eta (eta -> gamma gamma), respectively. The weighted average branching fraction is determined to be B(psi(3686) -> eta'e(+)e(-)) = (1.90 +/- 0.25 +/- 0.11) x 10(-6), where the first uncertainty is statistical and the second systematic.
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| 3. |
- Ablikim, M., et al.
(författare)
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Observation of the Semileptonic Decay D-0 -> a(0)(980)(-)e(+)nu(e) and Evidence for D+ -> a(0)(980)(0)e(+)nu(e)
- 2018
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Ingår i: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 121:8
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Tidskriftsartikel (refereegranskat)abstract
- Using an e(+)e(-) collision data sample of 2.93 fb(-1) collected at a center-of-mass energy of 3.773 GeV by the BESIII detector at BEPCII, we report the observation of D-0 -> a(0)(980)(-)e(+)nu(e) and evidence for D+ -> a(0)(980)(0)e(+)nu(e) with significances of 6.4 sigma and 2.9 sigma, respectively. The absolute branching fractions are determined to be B(D-0 -> a(0)(980)(-)e(+)nu(e)) x B(a(0)(980)(-) -> eta pi(-)) = [1.33(-0.29)(+0.33)(stat) +/- 0.09(syst)] x 10(-4) and B(D+ -> a(0)(980)(0)e(+)nu(e)) x B(a(0)(980)(0) -> eta pi(0)) = [1.66(-0.66)(+0.81)(stat) +/- 0.11(syst) x 10(-4). This is the first time the a(0)(980) meson has been measured in a D-0 semileptonic decay, which would open one more interesting page in the investigation of the nature of the puzzling a(0)(980) states.
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| 4. |
- Ablikim, M., et al.
(författare)
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Search for invisible decays of omega and phi with J/psi data at BESIII
- 2018
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Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 98:3
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Tidskriftsartikel (refereegranskat)abstract
- Using a data sample of (1310.6 +/- 7.0) x 10(6) J/psi events collected with the BESIII detector operating at the BEPCII collider, we perform the first experimental search for invisible decays of a light vector meson (V = omega, phi) via J/psi -> V-eta decays. The decay of eta -> pi(+)pi(-)pi(0) is utilized to tag the V meson decaying into the invisible final state. No evidence for a significant invisible signal is observed, and the upper limits on the ratio of branching fractions at the 90% confidence level are determined to be B(omega -> invisible)/B(omega -> pi(+)pi(-)pi(0)) < 8.1 x 10(-5) and B(phi -> invisible)/B(phi -> K+K-) < 3.4 x 10(-4). By using the world average values of B(omega -> pi(+)pi(-)pi(0) and B(phi -> K+K-,) the upper limits on the decay branching fractions at the 90% confidence level are set as B(omega -> invisible) < 7.3 x 10(-5) and B(phi -> invisible) < 1.7 x 10(-4), respectively.
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| 5. |
- Ablikim, M., et al.
(författare)
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Search for the rare decays D -> h(h((')))e(+) e(-)
- 2018
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Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 97:7
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Tidskriftsartikel (refereegranskat)abstract
- We search for rare decays of D mesons to hadrons accompanied by an electron-positron pair (h(h((')))e(+)e(- )),using an e(+)e(-) collision sample corresponding to an integrated luminosity of 2.93 fb(-1) collected with the BESIII detector at root s = 3.773 GeV. No significant signals are observed, and the corresponding upper limits on the branching fractions at the 90% confidence level are determined. The sensitivities of the results are at the level of 10(-5)-10(-6), providing a large improvement over previous searches.
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| 6. |
- Gao, Yun, et al.
(författare)
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Microsecond-response perovskite light-emitting diodes for active-matrix displays
- 2024
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Ingår i: NATURE ELECTRONICS. - : NATURE PORTFOLIO. - 2520-1131. ; 7:6
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Tidskriftsartikel (refereegranskat)abstract
- Perovskite light-emitting diodes (PeLEDs) could be of use in the development of active-matrix displays. However, due to ion migration in crystal structure, PeLEDs have electroluminescence rise times over milliseconds, which is problematic for the development of high-refresh-rate displays. Here, we show that the electroluminescence rise time of PeLEDs can be reduced to microseconds using an individual-particle passivation strategy. The approach is based on BF4 - ions that can passivate every nanocrystal in a perovskite emissive layer during film deposition. It leads to a defect-free film with discrete nanostructure and excellent crystallinity, which inhibits ion migration. Our strategy can be applied in perovskite nanocrystal films with different colours: red (635 nm), green (520 nm) and blue (475 nm). These PeLEDs all demonstrate response times within microseconds and high external quantum efficiencies of 22.7%, 26.2% and 18.1%, respectively. This allows us to create microsecond-response active-matrix PeLEDs that exhibit external quantum efficiencies above 20% at a display brightness of 500-3,000 cd m-2 for green devices with a resolution of 30 pixels per inch. We also develop microsecond-response red, green and blue active-matrix displays with 90 pixels per inch. An individual-particle passivation strategy that reduces ion migration in perovskite nanocrystal film can be used to make high-refresh-rate active-matrix displays with microsecond response times reduced by three orders of magnitude compared with typical perovskite light-emitting diodes.
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| 7. |
- Zhu, Zhifeng, et al.
(författare)
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Effect of gas temperature on composition concentration measurements by laser-induced breakdown spectroscopy
- 2023
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Ingår i: Journal of Analytical Atomic Spectrometry. - : Royal Society of Chemistry (RSC). - 0267-9477 .- 1364-5544. ; 38:2, s. 382-390
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Tidskriftsartikel (refereegranskat)abstract
- Laser-induced Breakdown Spectroscopy (LIBS) is widely applied to the quantitative measurement of gas composition concentrations. However, studies on the effect of gas temperature on LIBS are still lacking. Here, we investigated the effect of gas temperature on LIBS in terms of composition measurements in an air flow field. The air flow field was heated using a resistance wire to different gas temperatures ranging from 300-930 K in a heating tube. We evaluated the effect of gas temperature on the ratio of spectral line pairs, which is typically used for the calibrations of LIBS measurements. The variations in gas temperature change the ratio of spectral line pairs, which ultimately affects the accuracy of LIBS measurements. Further, the effect of gas temperature on the accuracy of LIBS measurements with different acquisition strategies was compared. The effects of gate width and delay time were investigated. An optimized acquisition strategy was proposed to reduce the effect of gas temperature on LIBS measurements. For LIBS measurements in gas flow fields, the effect of gas temperature on LIBS measurements can be reduced by using a large gate width and a suitable long delay time. The optimized acquisition strategy uses long-time averaging after an appropriate delay time to reduce the effect of gas temperature on plasma parameters. Finally, higher laser energy also helps to reduce the effect of gas temperature on LIBS measurements. In this paper, the LIBS measurement error caused by increasing the gas temperature from 300 K to 930 K is about 5%, roughly 0.8% per 100 K, with the optimized acquisition strategy. This paper can provide some help for LIBS measurements in gas samples with temperature variations.
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| 8. |
- Chong, Hui, et al.
(författare)
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Organo-ptii complexes for potent photodynamic inactivation of multi-drug resistant bacteria and the influence of configuration
- 2024
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Ingår i: Advanced Science. - : John Wiley & Sons. - 2198-3844. ; 11:14
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Tidskriftsartikel (refereegranskat)abstract
- PtII based organometallic photosensitizers (PSs) have emerged as novel potent photodynamic inactivation (PDI) reagents through their enhanced intersystem crossing (ISC) processes. Currently, few PtII PSs have been investigated as antibacterial materials, with relatively poor performances reported and with structure-activity relationships not well described. Herein, a pair of configurational isomers are reported of Bis-BODIPY (4,4-difluoro-boradizaindacene) embedded PtII PSs. The cis-isomer (cis-BBP) displayed enhanced 1O2 generation and better bacterial membrane anchoring capability as compared to the trans-isomer (trans-BBP). The effective PDI concentrations (efficiency > 99.9%) for cis-BBP in Acinetobacter baumannii (multi-drug resistant (MDR)) and Staphylococcus aureus are 400 nM (12 J cm−2) and 100 nM (18 J cm−2), respectively; corresponding concentrations and light doses for trans-BBP in the two bacteria are 2.50 µM (30 J cm−2) and 1.50 µM (18 J cm−2), respectively. The 50% and 90% minimum inhibitory concentration (MIC50 and MIC90) ratio of trans-BBP to cis-BBP is 22.22 and 24.02 in A. baumannii (MDR); 21.29 and 22.36 in methicillin resistant S. aureus (MRSA), respectively. Furthermore, cis-BBP displays superior in vivo antibacterial performance, with acceptable dark and photoinduced cytotoxicity. These results demonstrate cis-BBP is a robust light-assisted antibacterial reagent at sub-micromolecular concentrations. More importantly, configuration of PtII PSs should be an important issue to be considered in further PDI reagents design.
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| 9. |
- Dong, Xiaoyu, et al.
(författare)
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Gait Recognition Based on Modified OVR-CSP Fusion Feature and LSTM
- 2024
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Ingår i: 2024 7th International Conference on Advanced Algorithms and Control Engineering, ICAACE 2024. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 1551-1554
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Konferensbidrag (refereegranskat)abstract
- This paper proposes a gait recognition method based on the modified OVR-CSP fusion feature of plantar pressure and Long Short-Term Memory classification (referred to as the OVR-CSP-LSTM model). 10 subjects conducted 4 type of gait experiments including normal speed walking, fast walking, slow walking, imitating stroke gait walking in this paper. Transfer the commonly used Common Spatial Pattern (CSP) feature extraction method for EEG to plantar pressure signals, and splice the OVR-CSP features of 2-class, 3-class and 4-class, adopting Long Short Term Memory Network (LSTM) for classification. In this paper, the Intra-patient mode and Inter-patient mode of 10 people are modeled and compared respectively, and the recognition effects under different sensor number and different position sensors' combination are also studied. The experimental results show that the proposed model has good performance for both modes. The method proposed in this article is expected to be applied to multi-sensor signal processing and classification with spatial characteristics.
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| 10. |
- Fu, Zuhang, et al.
(författare)
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Fuel cell and hydrogen in maritime application : A review on aspects of technology, cost and regulations
- 2023
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Ingår i: Sustainable Energy Technologies and Assessments. - : Elsevier BV. - 2213-1388 .- 2213-1396. ; 57
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Tidskriftsartikel (refereegranskat)abstract
- Currently, fuel cell and hydrogen technology are attracting more and more attention as a kind of green and clean energy technology in the context of the increasingly stringent carbon emission requirements of the shipping industry. However, there are still many obstacles to their maritime application due to high costs and a lack of infrastructure. This paper conducts a literature survey of fuel cell maritime applications from four aspects: key technologies of fuel cell and hydrogen maritime applications, cost and standards. It can be concluded that ships powered by hydrogen fuel cells will have a broad application prospect with the maturity of the hydrogen industry chain and the improvement of standards and regulations. Two main contributions of this paper are to fully understand a whole-process perspective of hydrogen and fuel cell maritime application, and to provide the problems and future direction in this field, which can help relevant research institutions and scholars evaluate the development status of the industrial chain and find new valuable research topics.
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