| 31. |
- Zhang, Chi, et al.
(författare)
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A ship safe speed identifying method from risk perspectives in arctic waters
- 2020
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Ingår i: Proceedings of the 29th European Safety and Reliability Conference, ESREL 2019. - Singapore : Research Publishing Services. ; , s. 1874-1880
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Konferensbidrag (refereegranskat)abstract
- Increasingly melting of sea ice in the Arctic makes it possible for merchant ships with or without ice class to sail along the North Sea Routes, in particular during the summer seasons. However, ships sailing in the Arctic may still encounter thick (brash or level) ice in certain areas. It can challenge a ship's sailing safety. For safety concern, the ship speed selection is recognized as one of the leading challenges for the operators in the Arctic area. To figure out safe speed selection problem, the two most common accident scenarios- ice stuck and ship-ice collision have been analyzed. Through installing this risk analysis model, the safe speed under various ice conditions can be identified and the relevant results can provide beneficial information on speed selection for Arctic ships.
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| 32. |
- Zhang, Chi, et al.
(författare)
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An integrated risk assessment model for safe Arctic navigation
- 2020
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Ingår i: Transportation Research Part A: Policy and Practice. - : Elsevier BV. - 0965-8564. ; 142, s. 101-114
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Tidskriftsartikel (refereegranskat)abstract
- Safety is always the first concern for a ship's navigation in the Arctic. Ships navigating in the Arctic may face two main accident scenarios, i.e., getting stuck in the ice and ship-ice collision. More specifically, excessive speed may cause severe hull damage, while a very low speed may lead to a high probability of getting stuck in the ice. Based on this multi-risk perspective, an integrated risk assessment model was proposed to obtain the overall risk using the Bayesian Network (BN), in which the probabilities of accident occurrence and the severities of the possible consequences for ships getting stuck in the ice and for ship-ice collision could be estimated. Then, the voyage data collected from Yong Sheng's Arctic sailing in 2013 were inputted into the integrated risk assessment model to perform a case study. A sensitivity analysis was performed to validate the proposed model and reveal the inherent mechanisms behind these two accidental scenarios. The proposed model can be applied to identify the safe speed for Arctic navigation under various ice conditions, a duty that is traditionally performed by well-trained crew members, but which entails too many uncertainties. The results can, to some extent, provide useful suggestions for navigators. They are imperative in supporting decision-making to shape the Arctic policy and to enhance the safety of Arctic shipping.
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| 33. |
- Zhang, Chi, et al.
(författare)
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Data-driven ship energy efficiency analysis and optimization model for route planning in ice-covered Arctic waters
- 2019
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Ingår i: Ocean Engineering. - : Elsevier BV. - 0029-8018. ; 186
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Tidskriftsartikel (refereegranskat)abstract
- As increasing numbers of merchant ships navigate in the Arctic waters, more energy efficient navigation in the Arctic is needed for both economic and environmental purposes. This paper aims to provide a comprehensive analysis of energy efficiency of ice-going ships. Firstly, a data-driven model based on neural network theory is developed to predict the energy efficiency of ships in the Arctic. Then, a route with optimum energy efficiency is presented, intended to cut costs and be as environmentally friendly as possible. Finally, a case study is carried out to analyze the performance of a case study ship sailing at various environmental conditions. The results indicate that when planning the route for such an Arctic ship, it would be shortsighted only to focus on distance rather than energy efficiency. Moreover, the model shows good agreement between the simulation and real-life navigation. It is expected that the construction of this multi-angle, energy efficiency optimization model could help to improve Arctic navigation.
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| 34. |
- Zhang, Tianji, et al.
(författare)
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Interacting polymer-modification enzymes in heparan sulfate biosynthesis
- 2023
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Ingår i: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 299
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Tidskriftsartikel (refereegranskat)abstract
- Glucuronyl 5-epimerase (Hsepi) converts D-glucuronic acid (GlcA) into L-iduronic acid (IdoA) units, through a mechanism involving reversible abstraction of a proton at C5 of hexuronic acid residues. Incubations of a [4GlcA beta 1-4GlcNSO3 alpha 1-]n precursor substrate with recombinant enzymes in a D2O/H2O medium enabled an isotope exchange approach to the assessment of functional interactions of Hsepi with hexuronyl 2-O-sulfotrans-ferase (Hs2st) and glucosaminyl 6-O-sulfotransferase (Hs6st), both involved in the final polymer-modification steps. Enzyme complexes were supported by computational modeling and homogeneous time resolved fluores-cence. GlcA and IdoA D/H ratios related to product composition revealed kinetic isotope effects that were interpreted in terms of efficiency of the coupled epimerase and sulfotransferase reactions. Evidence for a func-tional Hsepi/Hs6st complex was provided by selective incorporation of D atoms into GlcA units adjacent to 6-O -sulfated glucosamine residues. The inability to achieve simultaneous 2-O-and 6-O-sulfation in vitro supported topologically separated reactions in the cell. These findings provide novel insight into the roles of enzyme in-teractions in heparan sulfate biosynthesis.
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| 35. |
- Zhang, Wei, et al.
(författare)
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Critical Role of Phosphorus in Hollow Structures Cobalt-Based Phosphides as Bifunctional Catalysts for Water Splitting
- 2022
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 18:4
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Tidskriftsartikel (refereegranskat)abstract
- Cobalt phosphides electrocatalysts have great potential for water splitting, but the unclear active sides hinder the further development of cobalt phosphides. Wherein, three different cobalt phosphides with the same hollow structure morphology (CoP-HS, CoP2-HS, CoP3-HS) based on the same sacrificial template of ZIF-67 are prepared. Surprisingly, these cobalt phosphides exhibit similar OER performances but quite different HER performances. The identical OER performance of these CoPx-HS in alkaline solution is attributed to the similar surface reconstruction to CoOOH. CoP-HS exhibits the best catalytic activity for HER among these CoPx-HS in both acidic and alkaline media, originating from the adjusted electronic density of phosphorus to affect absorption–desorption process on H. Moreover, the calculated ΔGH* based on P-sites of CoP-HS follows a quite similar trend with the normalized overpotential and Tafel slope, indicating the important role of P-sites for the HER process. Moreover, CoP-HS displays good performance (cell voltage of 1.67 V at a current density of 50 mA cm−2) and high stability in 1 M KOH. For the first time, this work detailly presents the critical role of phosphorus in cobalt-based phosphides for water splitting, which provides the guidance for future investigations on transition metal phosphides from material design to mechanism understanding.
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| 36. |
- Zou, Haiyang, et al.
(författare)
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Dramatically Enhanced Broadband Photodetection by Dual Inversion Layers and Fowler-Nordheim Tunneling
- 2019
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 13:2, s. 2289-2297
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Tidskriftsartikel (refereegranskat)abstract
- Silicon photonics is now widely accepted as a key technology in a variety of systems. But owing to material limitations, now it is challenging to greatly improve the performance after decades of development. Here, we show a high-performance broadband photodetector with significantly enhanced sensitivity and responsivity operating over a wide wavelength range of light from near-ultraviolet to near-infrared at low power consumption. The specially designed textured top ceiling electrode works effectively as an antireflection layer to greatly improve the absorption of near-infrared light, thereby overcoming the absorption limitation of near-infrared light. Instead of the conventional p-n junction and p-intrinsic-n junction, we introduce a similar to 15 nm thick alumina insulator layer between a p-type Si substrate and n-type ZnO nanowire (NW) arrays, which significantly enhances the charge carrier separation and collection efficiency. The photosensing responsivity and sensitivity are found to be nearly 1 order of magnitude higher than that of a reference device of p-Si/n-ZnO NW arrays, significantly higher than the commercial silicon photodiodes as well. The light-induced charge carriers flow across the appropriate thickness of insulator layer via the quantum mechanical Fowler-Nordheim tunneling mechanism. By virtue of the piezo-phototronic effect, the charge density at the interfaces can be tuned to alter the energy bands and the potential barrier distance for tunneling. Additionally, along with the use of incident light of different wavelengths, the influence of the insulator layer on the transport of electrons and holes separately is further investigated. The demonstrated concepts and study would lead to sensitivity improvement, quality enhancement of data transfer, decrease of power consumption, and cost reduction of silicon photonics.
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| 37. |
- Adcox, K, et al.
(författare)
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Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX Collaboration
- 2005
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Ingår i: Nuclear Physics, Section A. - : Elsevier BV. - 0375-9474. ; 757:1-2, s. 184-283
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Forskningsöversikt (refereegranskat)abstract
- Extensive experimental data from high-energy nucleus-nucleus collisions were recorded using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The comprehensive set of measurements from the first three years of RHIC operation includes charged particle multiplicities, transverse energy, yield ratios and spectra of identified hadrons in a wide range of transverse momenta (PT), elliptic flow, two-particle correlations, nonstatistical fluctuations, and suppression of particle production at high PT. The results are examined with an emphasis on implications for the formation of a new state of dense matter. We find that the state of matter created at RHIC cannot be described in terms of ordinary color neutral hadrons.
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| 38. |
- Albrecht, Stefano V., et al.
(författare)
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Reports on the 2015 AAAI Workshop Series
- 2015
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Ingår i: The AI Magazine. - : Wiley. - 0738-4602 .- 2371-9621. ; 36:2, s. 90-101
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Tidskriftsartikel (refereegranskat)abstract
- AAAI's 2015 Workshop Program was held Sunday and Monday, January 25-26, 2015, at the Hyatt Regency Austin Hotel in Austin, Texas, USA. The AAAI-15 workshop program included 16 workshops covering a wide range of topics in artificial intelligence. Most workshops were held on a single day. The titles of the workshops included Algorithm Configuration; Artificial Intelligence and Ethics; Artificial Intelligence Applied to Assistive Technologies and Smart Environments; Artificial Intelligence for Cities; Artificial Intelligence for Transportation: Advice, Inter-activity, and Actor Modeling; Beyond the Turing Test; Computational Sustainability; Computer Poker and Imperfect Information; Incentive and Trust in E-Communities; Knowledge, Skill, and Behavior Transfer in Autonomous Robots; Learning for General Competency in Video Games; Multiagent Interaction without Prior Coordination; Planning, Search, and Optimization; Scholarly Big Data: AI Perspectives, Challenges, and Ideas; Trajectory-Based Behaviour Analytics; and World Wide Web and Public Health Intelligence.
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| 39. |
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| 40. |
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