| 1. |
- Chen, Qingguo, et al.
(författare)
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Preparation and properties of Ce0.5Nd0.5PO4 monazite ceramics by pressureless sintering and spark plasma sintering (SPS)
- 2024
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Ingår i: Ceramics International. - : Elsevier. - 0272-8842 .- 1873-3956. ; 50:12, s. 20803-20810
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Tidskriftsartikel (refereegranskat)abstract
- LnPO4·nH2O rhabdophane/monazite is an important actinide-bearing material in the back end of the nuclear fuel cycle. In this work, using Nd3+ to simulate trivalent actinides, Ce0.5Nd0.5PO4·0.667H2O rhabdophane was synthesized by the wet-chemistry method in 90 °C and pH = 1 solution. The sintering behavior of associated Ce0.5Nd0.5PO4 monazite ceramics was investigated by pressureless sintering and spark plasma sintering (SPS), along with appraising their chemical stability. The results reveal that Ce3+ is successfully replaced by Nd3+ in the rhabdophane lattice, and rhabdophane can transform to monazite with a temperature over 750 °C. SPS can compact the ceramic sample at a lower temperature compared to pressureless sintering even if the grain size is smaller. Adding a pre-sintering process of 900 °C before SPS and pressureless sintering will further improve the density and Vickers hardness of ceramics. For the chemical stability of Ce0.5Nd0.5PO4 monazite ceramics, Ce is more likely to be leached compared to Nd, and the ceramics prepared by SPS with a pre-sintering process have the lowest normalized leaching rates, associated with the values of 2.03 × 10−5 g·m−2·d−1 and 0.75 × 10−5 g·m−2·d−1 for Ce and Nd, respectively.
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| 2. |
- Chen, Tao, et al.
(författare)
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SinoPedia—A Linked Data Services platform for decentralized knowledge base
- 2019
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14:8
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge bases are largely developed and utilized in academic and industrial fields, such as DBPedia, VIAF, LoC, Getty, and which are published in the Linked Data format. However, if you want to view different resources on these knowledge bases, you have to switch between different web pages from these resources. Therefore, we proposed a decentralized data hub named SinoPedia, which consists of several linked data services and can re-publish these RDF data in one platform. Firstly, these different Linked Data services include: Linked Data Transformation Service (LDTS), Linked Data Query Service (LDQS), Linked Data Publishing Service (LDPS) and Linked Data Knowledge Service (LDKS). The resource URI is the basis and core of the linked data, thus we will focus on the resource forwarding mechanism in LDPS service which can rewrite resource URI using a global and standard format among knowledge bases. Some knowledge bases were configured in SinoPedia platform in this paper. In addition to the above services, Linked Data Reasoning Service (LDRS) and Linked Data Intelligence Service (LDIS) will be added to the platform in the future. In short, all of these Linked Data Services will form the core framework in order to providing a good linked data application ecosystem.
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| 3. |
- Lin, Xiang, et al.
(författare)
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Ionic Conjugated Microporous Polymers for Cycloaddition of Carbon Dioxide to Epoxides
- 2024
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Ingår i: Macromolecular materials and engineering. - 1438-7492 .- 1439-2054. ; 309:2
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Tidskriftsartikel (refereegranskat)abstract
- Along the development of ionic porous organic polymers, simple and efficient synthetic methods are actively pursued. Herein, the Debus–Radziszewski reaction is applied to synthesize ionic conjugated microporous polymers (iCMPs) in one step. A series of imidazolium-linked iCMP-X (X = 1, 2, 3) are developed for CO2 sorption and in situ conversion with epoxide into cyclic carbonates. The as-synthesized iCMPs are characterized in detail by scanning electron microscope, solid-state nuclear magnetic resonance, X-ray photoelectron spectroscopy, X-ray diffraction analysis, N2/CO2 sorption, and more. Among all synthesized iCMPs, iCMP-1 possesses the highest specific surface area and in turn the strongest CO2 sorption capacity. Moreover, through a simple anion ion exchange reaction with halide, iCMP-1 is transformed to iCMP-1@Cl that embodies significant catalytic capability for converting CO2 into cyclic carbonates.
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| 4. |
- Wang, Dongsheng, et al.
(författare)
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Publishing E-RDF linked data for many agents by single third-party server
- 2017
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Ingår i: Semantic Technology - 7th Joint International Conference, JIST 2017, Proceedings. - Cham : Springer International Publishing. - 1611-3349 .- 0302-9743. - 9783319706818 ; 10675 LNCS, s. 151-163
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Konferensbidrag (refereegranskat)abstract
- Linked data is one of the most successful practices in semantic web, which has led to the opening and interlinking of data. Though many agents (mostly academic organizations and government) have published a large amount of linked data, numerous agents such as private companies and industries either do not have the ability or do not want to make an additional effort to publish linked data. Thus, for agents who are willing to open part of their data but do not want to make an effort, the task can be undertaken by a professional third-party server (together with professional experts) that publishes linked data for these agents. Consequently, when a single third-party server is on behalf of multiple agents, it is also responsible to organize these multiple-source URIs (data) in a systematic way to make them referable, satisfying the 4-star data principles, as well as protect the confidential data of these agents. In this paper, we propose a framework to leverage these challenges and design a URI standard based on our proposed E-RDF, which extends and optimizes the existing 5-star linked data principles. Also, we introduce a customized data filtering mechanism to protect the confidential data. For validation, we implement a prototype system as a third-party server that publishes linked data for a number of agents. It demonstrates well-organized 5-star linked data plus E-RDF and shows the additional advantages of data integration and interlinking among agents.
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| 5. |
- Wang, Yachao, et al.
(författare)
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A new method to assess vehicle airborne non-exhaust particles : Principle, application and emission evaluation
- 2023
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Ingår i: Applied Energy. - 0306-2619. ; 352
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Tidskriftsartikel (refereegranskat)abstract
- A method that could assess the whole vehicle non-exhaust particle (NEP) emission from the whole vehicle level was proposed by combining sealed housing with the chassis dynamometer. The intake and exhaust systems were connected to the out of the chamber to avoid possible effects on NEP emissions. The most distinguishing feature of the proposed method is the whole vehicle assessment of the NEP. Based on the proposed method, three vehicles were tested under various conditions. The results proved that the total NEP from the US06 cycle could be four orders of magnitude higher than that of the WLTC cycle due to the higher thermal load. The transient NEP concentration is highly associated with the friction pairs' temperature, and there are two critical temperatures respectively for volatile particles and solid particles. Mechanical friction-dominated test (WLTC) tends to produce larger particles, while thermal process-dominated tests (US06) tend to emit smaller particles. Solid particles occupy <10% of the total particles, and solid particle is dominated with the size at 10– 23 nm. The higher the brake temperature, the higher the solid particle emissions (both concentration and portion). NEP emission decreases when vehicle miles travelled increase. Total NEP number emission factors could be two orders of magnitude higher than the current PN limit for exhaust particles (6*1011#/km). The solid particle emission factor could also be ten times higher than the current PN limit. O and Fe element distribution matches well with the SEM image, which means the proposed method could successfully sample the brake particles. The carbon element weight is dominated by the organic carbon, which might mean that it's the mechanical abrasion dominate the carbon mass. The top 5 dominant element during ICP/MS analysis is Si, Na, Mg, Zn, and Al.
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| 6. |
- Zhao, Xiaofeng, et al.
(författare)
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Incorporation of Th4+ and Sr2+ into Rhabdophane/Monazite by Wet Chemistry : Structure and Phase Stability
- 2023
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 62:38, s. 15605-15615
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Tidskriftsartikel (refereegranskat)abstract
- Rhabdophane is an important permeable reactive barrier to enrich radionuclides from groundwater and has been envisaged to host radionuclides in the backend of the nuclear fuel cycle. However, understanding of how An4+ and Sr2+ precipitate into rhabdophane by wet chemistry has not been resolved. In this work, Th4+ and Sr2+ incorporation in the rhabdophane/ monazite structure as La1-2xSrxThxPO4.nH2O solid solutions is successfully achieved in the acid solution at 90 degrees C. Some specific issues such as lattice occupation of Th4+ and Sr2+, precipitation reaction kinetics, and crystal growth affected by starting stoichiometry are discussed in detail, along with investigating the chemical stability of La1-2xSrxThxPO4.nH2O precipitations and associated La(1-2x)Sr(x)ThxPO(4) monazite. The results reveal that the excess of Sr2+ appears to be a prevailing factor with a suggested initial Sr: Th = 2 to obtain the stability domain of La1-2xSrxThxPO4.nH(2)O (x = 0 similar to 0.1). A rapid ion removal associated with a nucleation process has been observed within 8 h, and Th4+ can be removed more than 98% after 24 h in 0.01 mol/L solutions. From structural energetics based on density functional theory, the lattice occupation of Th4+ and Sr2+ is energetically favorable in nonhydrated lattice sites of [LaO8], although two-thirds of lattice sites are associated with [LaO8.H2O] hydrated sites. Intriguingly, the crystal transformation from rhabdophane to monazite associated with the transformation from [SrO8] to [SrO9] polyhedra can greatly improve the leaching stability of Sr2+.
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