| 1. |
- Fan, Jin, et al.
(författare)
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Design of Octave-bandwidth Phased Array Feed for Large Radio Telescope
- 2019
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Ingår i: 13th European Conference on Antennas and Propagation, EuCAP 2019.
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Konferensbidrag (refereegranskat)abstract
- This paper presents design scenarios of Octave-bandwidth Phase Array Feed (PAF) based on a novel wideband dual polarized tightly-fed Bowtie antenna element. The PAF is optimized for the 4 - 8GHz band aiming to possible later integration in the SKA pathfinder PHAROS2. The proposed design can be a good candidate of PAF for the Five hundred meter Aperture Spherical Telescope (FAST) and Qi Tai Telescope (QTT) as well as other large radio telescopes.
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| 2. |
- Su, Wenyan, et al.
(författare)
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13.4 % Efficiency from All-Small-Molecule Organic Solar Cells Based on a Crystalline Donor with Chlorine and Trialkylsilyl Substitutions
- 2021
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 14:17, s. 3535-3543
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Tidskriftsartikel (refereegranskat)abstract
- How to simultaneously achieve both high open-circuit voltage (Voc) and high short-circuit current density (Jsc) is a big challenge for realising high power conversion efficiency (PCE) in all-small-molecule organic solar cells (all-SM OSCs). Herein, a novel small molecule (SM)-donor, namely FYSM−SiCl, with trialkylsilyl and chlorine substitutions was designed and synthesized. Compared to the original SM-donor FYSM−H, FYSM−Si with trialkylsilyl substitution showed a decreased crystallinity and lower highest occupied molecular orbital (HOMO) level, while FYSM−SiCl had an improved crystallinity, more ordered packing arrangement, significantly lower HOMO level, and predominant “face-on” orientation. Matched with a SM-acceptor Y6, the FYSM−SiCl-based all-SM OSCs exhibited both high Voc of 0.85 V and high Jsc of 23.7 mA cm−2, which is rare for all-SM OSCs and could be attributed to the low HOMO level of FYSM−SiCl donor and the delicate balance between high crystallinity and suitable blend morphology. As a result, FYSM−SiCl achieved a high PCE of 13.4 % in all-SM OSCs, which was much higher than those of the FYSM−H- (10.9 %) and FYSM−Si-based devices (12.2 %). This work demonstrated a promising method for the design of efficient SM-donors by a side-chain engineering strategy via the introduction of trialkylsilyl and chlorine substitutions.
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| 3. |
- Chen, Huang, et al.
(författare)
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A portable micro glucose sensor based on copper-based nanocomposite structure
- 2019
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1369-9261 .- 1144-0546. ; 43:20, s. 7806-7813
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Tidskriftsartikel (refereegranskat)abstract
- Precisely detecting the concentration of glucose in the human body is an attractive way to prevent or treat diabetes. Portable glucose sensors with non-enzymatic catalytic materials have received great attention in recent years. Herein, a facile strategy for fabricating a high-performance electrochemical sensor is proposed. A non-enzymatic three-electrode integrated glucose sensor device based on CuO nano-coral arrays/nanoporous Cu (NCA/NPC) is designed and fabricated. The portable NCA/NPC glucose sensor device exhibits high catalytic activity for glucose. The great performance of the NCA/NPC glucose sensor device derives from the excellent conductivity of the NPC substrate and the high electrocatalytic activity of CuO nano-coral arrays. This device exhibits a high sensitivity of 1621 μA mM -1 cm -2 in the linear range of 0.0005-5.0 mM, low detection limit of 200 nM (S/N = 3), fast response time of 3 s, good anti-interference performance, excellent repeatability and considerable stability for glucose detection. This work will certainly provide an efficient structure and proper catalytic material choices for future non-enzymatic glucose sensors.
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| 4. |
- Lin, Jiachun, et al.
(författare)
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Gear wear prediction based on the theorem of degradation entropy generation
- 2024
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Ingår i: Tribology International. - : Elsevier BV. - 0301-679X .- 1879-2464. ; 191
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Tidskriftsartikel (refereegranskat)abstract
- Tooth surface material loss caused by gear wear alters the surface morphology of gears, which impacts their vibration, noise, and remaining lifespan. Although gear wear modeling and prediction have been extensively studied, this paper proposes a novel approach based on the theorem of degradation entropy generation (DEG). A point-by-point calculation method is introduced to determine the degradation coefficient for each measurement point on the tooth profile, accounting for varying working conditions along the tooth profile during the actual meshing process of the gear pair. First, the FZG gear's bearing capacity is tested. Next, a surface roughness profilometer is employed to in-situ measure the tooth profile after each load stage. The profile deviation curve and the amount of profile wear following each load stage are obtained by processing the measured profile morphology data. Then, the pitting safety factor for each point on the tooth surface is calculated according to the ISO 6336–22:2018 standard and used to correct the degradation coefficient for that point. Finally, the entropy generation of the system during each load stage of the FZG gear is calculated. The degradation coefficient suggested in the DEG theorem is employed to link gear wear with system entropy generation, realizing gear wear modeling and prediction. The results demonstrate that the gear wear calculation method based on the DEG theorem can accurately predict the evolution of tooth profile surface morphology during the experimental process. This research provides a unified calculation method for surface morphology evolution caused by gear wear during service.
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| 5. |
- Su, Peng, et al.
(författare)
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Scheduling Resource to Deploy Monitors in Automated Driving Systems
- 2023
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Ingår i: Dependable Computer Systems and Networks. - : Springer Nature. ; , s. 285-294
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Konferensbidrag (refereegranskat)abstract
- Deep Neural Networks (DNN) constitute an important technology for operational perception in Automated Driving Systems (ADS). However, the trustworthiness of such DNN is one concern in the system engineering and quality management. Therefore, it is critical to monitor conditions and ensure the safety of the implementations for this advanced technology. One solution is to use Conditional Monitors (CM) to detect possible faults. However, such monitors challenge resource (e.g., data and memory) management of limited memory space in the ADS hardware. This paper proposes a resource scheme for deploying a monitor in ADS by integrating dynamic memory scheduling with Responsibility-Sensitive Safety (RSS). We use the car-following system as a case study to evaluate our scheme. YOLOv5 and KITTI datasets simulate a perception module where various monitors detect faults. We measure the time cost of conventional scheduling pipelines and our method. Compared with the conventional method, our scheme reduces 43.7% of execution time per cycle.
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| 6. |
- Wang, Fang, et al.
(författare)
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Numerical Reconstruction of Cyclist Impact Accidents : Can Helmets Protect the Head-Neck of Cyclists?
- 2023
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Ingår i: Biomimetics. - : MDPI AG. - 2313-7673. ; 8:6
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Tidskriftsartikel (refereegranskat)abstract
- Cyclists are vulnerable road users and often suffer head-neck injuries in car–cyclist accidents. Wearing a helmet is currently the most prevalent protection method against such injuries. Today, there is an ongoing debate about the ability of helmets to protect the cyclists’ head-neck from injury. In the current study, we numerically reconstructed five real-world car–cyclist impact accidents, incorporating previously developed finite element models of four cyclist helmets to evaluate their protective performances. We made comparative head-neck injury predictions for unhelmeted and helmeted cyclists. The results show that helmets could clearly lower the risk of severe (AIS 4+) brain injury and skull fracture, as assessed by the predicted head injury criterion (HIC), while a relatively limited decrease in AIS 4+ brain injury risk can be achieved in terms of the analysis of CSDM0.25. Assessment using the maximum principal strain (MPS0.98) and head impact power (HIP) criteria suggests that helmets could lower the risk of diffuse axonal injury and subdural hematoma of the cyclist. The helmet efficacy in neck protection depends on the impact scenario. Therefore, wearing a helmet does not seem to cause a significant neck injury risk level increase to the cyclist. Our work presents important insights into the helmet’s efficacy in protecting the head-neck of cyclists and motivates further optimization of protective equipment.
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| 7. |
- Zhong, Shenghui, et al.
(författare)
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Large eddy simulation of n-heptane/syngas pilot ignition spray combustion : Ignition process, liftoff evolution and pollutant emissions
- 2021
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Ingår i: Energy. - : Elsevier BV. - 0360-5442. ; 233
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Tidskriftsartikel (refereegranskat)abstract
- The utilization of syngas in the internal combustion engine is one way to reach low carbon emission engine. The n-heptane/syngas pilot ignition spray combustion is simulated here by high fidelity model with different syngas compositions. It is found that the ambient syngas suppresses the ignition by diluting the ambient oxidizer (non-chemical effect) and by affecting the chemical reactions (chemical effect). The consumption of OH radicals through H2+OH = H + H2O and CO + OH = CO2+H in low temperature combustion (LTC) stage is shown to be the main reason for the suppression of ignition. Cool flame propagation into the rich mixture in the mixing layer of n-heptane jet is observed during the transition process from LTC to high temperature combustion (HTC). CO is found to assist the transition to HTC through CO + HO2 = CO2+OH. On the contrary, H2 slows down the cool flame propagation and narrows down the cool flame flammability range, which retards the onset of HTC. The effects of syngas compositions on the flame structure and emission formation are discussed in detail. Due to the upstream auto-ignition, a cool/diffusion/hot flame structure is identified at the liftoff position in dual-fuel case, which drastically changes the flame structure. And more soot formation in early stage is found in dual-fuel cases due to the naturally richer mixture.
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| 8. |
- Lv, Zhong-Peng, et al.
(författare)
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Cation field-strength effects on ion irradiation-induced mechanical property changes of borosilicate glass structures
- 2023
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Ingår i: Journal of The American Ceramic Society. - 0002-7820 .- 1551-2916. ; 106:10, s. 5766-5780
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Tidskriftsartikel (refereegranskat)abstract
- We examine the impact of the glass network-modifier cation field strength (CFS) on ion irradiation-induced mechanical property changes in borosilicate (BS) glasses for the ternary M2O-B2O3-SiO2 systems with M = {Na, K, Rb} and the quaternary [0.5M((2))O-0.5Na(2)O]-B2O3-SiO2 systems with M = {Li, Na, K, Rb Mg, Ca, Sr, Ba}. B-11 nuclear magnetic resonance (NMR) experiments on the as-prepared BS glasses yielded the fractional population of four-coordinated B species (B-[4]) out of all {B-[3], B-[4]} groups in the glass network, along with the fraction of B-[4]-O-Si linkages out of all B-[4]-O-Si/B bonds. Both parameters correlated linearly with the (average) CFS of the M+ and/or {M(2)+, Na+} cations. Both the nanoindentation-derived hardness and Young's modulus values of the glasses reduced upon their irradiation by Si2+ ions, with the property deterioration decreasing linearly with increasing Mz+ CFS, that is, for higher Mz+center dot center dot center dot O interaction strength. The irradiation damage of the glass network also increased linearly with the fraction of B-[4]-O-Si linkages, which are the second weakest in the structure after the Mz+center dot center dot center dot O bonds. Our results underscore the advantages of employing BS glasses with high-CFS cations for enhancing the radiation resistance for nuclear waste storage.
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| 9. |
- Zhu, Youjian, et al.
(författare)
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P-Based Additive for Reducing Fine Particulate Matter Emissions during Agricultural Biomass Combustion
- 2019
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 33:11, s. 11274-11284
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Tidskriftsartikel (refereegranskat)abstract
- To understand the influence of P-containing compounds on particulate matter (PM) emissions from the combustion of agricultural residues, the combustion of cornstalk was performed with the addition of a phosphorus-based additive, namely, ammonium dihydrogen phosphate (NH4H2PO4), in a fixed-bed combustion system. Simultaneously the ash samples, including PM collected by a Dekati low-pressure impactor (DLPI) and residual ash, were analyzed with variant analytical techniques. It was found that NH4H2PO4 addition significantly reduced PM0.1 and PM0.1-1 yields but increased PM1-10 yields. The maximum PM0.1 and PM1 reduction efficiency can reach up to 50% at an optimal P/K molar ratio equal to 1. Meanwhile, the addition of NH4H2PO4 to cornstalk changed the chemical composition of PM1 from being dominated by KCl and KOH/K2CO3 with a small amount of K2SO4 to a system dominated by KPO3 and KCl with a small amount of K2SO4. Simultaneously, the possible PM1 reduction mechanism was proposed. In addition, the residual ash after combustion was rich in K- and P-containing species, indicating a potential utilization as a fertilizer. It showed that the addition of NH4H2PO4 is a promising approach to reduce PM1 emissions during the combustion of agricultural biomass.
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| 10. |
- Fan, Jin, et al.
(författare)
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Design of Novel Flat Bend Crossed Dipole for Wideband Phased Array Feed Applications
- 2019
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Ingår i: 2019 International Symposium on Antennas and Propagation, ISAP 2019 - Proceedings.
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Konferensbidrag (refereegranskat)abstract
- This paper presents a novel Phased Array Feed (PAF) element based on flat bend crossed dipole fed by 50-Ohm coaxial line. The PAF element is dual-polarized and made from all-metal to minimize Ohmic losses and simplify cryogenic integration. It is optimized for 4- 8 GHz band aiming to possible later integration in the SKA pathfinder PHAROS2. The proposed design can also be a good element candidate of PAF for the Five hundred meter Aperture Spherical Telescope (FAST) and Qi Tai Telescope (QTT) as well as other large radio telescopes.
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