| 1. |
- Song, Tengfei, et al.
(författare)
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Effect of carbonization conditions on the property and structure of bamboo char for injection in blast furnace
- 2019
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Ingår i: ISIJ International. - : Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 59:3, s. 442-449
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Tidskriftsartikel (refereegranskat)abstract
- To evaluate the effect of carbonization conditions on the bamboo, the relationship between carbonization parameter and physicochemical characteristics was studied. The results indicated that the volatile matter drastically decreased with the increase of carbonization temperature, while the fixed carbon and fuel ratio (fixed carbon/volatile matter) increased. Excellent linearity between the fuel ratio and carbonization temperature was obtained. The energy yield decreased gradually when rising the carbonization temperature, whereas the change of heating value was not obvious. A new calculation model of higher heating value (HHV) was developed, and it could be used to predict HHV of the bamboo char more precisely at temperatures above 300°C. The positive impact of functional groups, specific surface area as well as catalysis of alkali metal may contribute to the combustion of bamboo char. The results showed that there is a feasible operating condition for the transformation of bamboo into char with the carbonization parameter at 400°C for 30 min.
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| 2. |
- Zhang, Yinping, et al.
(författare)
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Ten cities cross-sectional questionnaire survey of children asthma and other allergies in China
- 2013
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Ingår i: Chinese Science Bulletin. - : Springer Science and Business Media LLC. - 1001-6538 .- 1861-9541. ; 58:34, s. 4182-4189
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Tidskriftsartikel (refereegranskat)abstract
- Asthma, rhinitis and eczema (allergic or non-allergic) have increased throughout the world during the last decades, especially among children. Changes in the indoor environment are suspected to be important causes. China has experienced a dramatic change in indoor environmental exposures during the past two decades. However, such changes and their associations with children's asthma and other health aspects have not been thoroughly studied. China, Children, Homes, Health (CCHH), Phase I, was a cross-sectional questionnaire survey of 48219 children 1-8 years old in 10 Chinese cities during 2010-2012. The questionnaire includes the International Study of Asthma and Allergies in Childhood (ISAAC) core health questions and additional questions regarding housing, life habits and outdoor environment. In health analyses, children aged 3-6 years old were included. The prevalences of doctor diagnosed asthma varied from 1.7% to 9.8% (mean 6.8%), a large increase from 0.91% in 1999 and 1.50% in 2000. The prevalence of wheeze, rhinitis and atopic eczema (last 12 months) varied from 13.9% to 23.7%, 24.0% to 50.8% and 4.8% to 15.8%, respectively. Taiyuan had the lowest prevalences of all illnesses and Shanghai the highest, except for wheezewhere the highest value was for Urumqi. We found (1) no obvious association between disease prevalences and ambient PM10 concentrations and (2) higher prevalences of disease in humid climates with hot summers and cold winters, but with no centrally heated buildings. Associations between the diseases and economic status as indexed by Gross Domestic Product (GDP) requires further study.
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| 3. |
- Ling, Chen, et al.
(författare)
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A comprehensive consumption-based carbon accounting framework for power system towards low-carbon transition
- 2024
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier Ltd. - 1364-0321 .- 1879-0690. ; 206
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Tidskriftsartikel (refereegranskat)abstract
- Nearly 40 % current global annual energy-related CO2 emissions come from the fossil fuel-dominated power sector. Accurately accounting for carbon emissions in power systems from the consumption-based perspective is crucial for achieving the low-carbon power transition. Consumption-based carbon accounting has emerged as a major research focus, which aids in the implementation of targeted measures such as low-carbon demand response and dispatch. Choosing an appropriate method to account carbon emission needs thorough consideration of characteristics of various methods. There still lacks a systematic review that concludes the essence and application status of these methods, as well as comparing their advantages and disadvantages. To address this gap, a consumption-based carbon accounting framework for power systems is proposed. This framework groups four typical methods into two perspectives: Attributional methods and consequential methods. The principles, calculation approaches, and research application status of these methods are comprehensively summarized in a transparent, integrated and comparative manner, which makes progress in two critical limitations: (i) temporal and spatial granularity, and (ii) consideration of the actual topology and operational constraints of the power grid. As improvements in the transparency and quality of electricity data and expansion of application scenarios, the flexibility and applicability of the framework will continue to improve to achieve the unity of efficiency and fairness. The proposed framework can serve as a valuable guide to conducting research and exploration on low-carbon energy management, policy and regulatory decisions and to inform the development of effective strategies for the low-carbon transition of power systems.
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| 4. |
- Bhadoria, Shubhangi, et al.
(författare)
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Enablers for Overcurrent Capability of Silicon-Carbide-Based Power Converters : An Overview
- 2023
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Ingår i: IEEE transactions on power electronics. - : Institute of Electrical and Electronics Engineers Inc.. - 0885-8993 .- 1941-0107. ; 38:3, s. 3569-3589
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Tidskriftsartikel (refereegranskat)abstract
- With the increase in penetration of power electronic converters in the power systems, a demand for overcurrent/ overloading capability has risen for the fault clearance duration. This article gives an overview of the limiting factors and the recent technologies for the overcurrent performance of SiC power modules in power electronics converters. It presents the limitations produced at the power module level by packaging materials, which include semiconductor chips, substrates, metallization, bonding techniques, die attach, and encapsulation materials. Specifically, technologies for overcurrent related temperatures in excess of 200°C are discussed. This article also discusses potential technologies, which have been proven or may be potential candidates for improving the safe operating area. The discussed technologies are use of phase-change materials below the semiconductor chip, Peltier elements, new layouts of the power modules, control and modulation techniques for converters. Special attention has been given to an overview of various potential phase-change materials, which can be considered for high-temperature operations.
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| 5. |
- Gong, Qingyuan, et al.
(författare)
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Exploring the power of social hub services
- 2019
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Ingår i: World wide web (Bussum). - : Springer Science and Business Media LLC. - 1386-145X .- 1573-1413. ; 22:6, s. 2825-2852
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Tidskriftsartikel (refereegranskat)abstract
- Given the diverse focuses of emerging online social networks (OSNs), it is common that a user has signed up on multiple OSNs. Social hub services, a.k.a., social directory services, help each user manage and exhibit her OSN accounts on one webpage. In this work, we conduct a data-driven study by crawling over one million user profiles from about.me, a representative online social hub service. Our study aims at gaining insights on cross-OSN social influence from the crawled data. We first analyze the composition of the social hub users. For each user, we collect her social accounts from her social hub webpage, and aggregate the content generated by these accounts on different OSNs to gain a comprehensive view of this user. According to our analysis, there is a high probability that a user would provide consistent information on different OSNs. We then explore the correlation between user activities on different OSNs, based on which we propose a cross-OSN social influence prediction model. With the model, we can accurately predict a user’s social influence on emerging OSNs, such as Instagram, Foursquare, and Flickr, based on her data published on well-established OSNs like Twitter.
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| 6. |
- Hakonen, Aron, 1970, et al.
(författare)
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Hand-Held Femtogram Detection of Hazardous Picric Acid with Hydrophobic Ag Nanopillar SERS Substrates and Mechanism of Elasto-Capillarity
- 2017
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Ingår i: ACS Sensors. - : American Chemical Society (ACS). - 2379-3694. ; 2:2, s. 198-202
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Tidskriftsartikel (refereegranskat)abstract
- Picric acid (PA) is a severe environmental and security risk due to its unstab e, toxic, and explosive properties. It is also challenging to detect in trace amounts and in situ because of its highly acidic and anionic character. Here, we assess sensing of PA under nonlaboratory conditions using surface-enhanced Raman scattering (SERS) silver nanopillar substrates and handheld Raman spectroscopy equipment. The advancing elasto-capillarity effects are explained by molecular dynamics simulations. We obtain a SERS PA detection limit on the order of 20 ppt, corresponding attomole amounts, which together with the simple analysis methodology demonstrates that the presented approach is highly competitive for ultrasensitive analysis in the field.
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| 10. |
- Zhu, G., et al.
(författare)
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Synergistic reduction on PM and NO source emissions during preheating-combustion of pulverized coal
- 2024
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Ingår i: Fuel. - : Elsevier Ltd. - 0016-2361 .- 1873-7153. ; 361
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Tidskriftsartikel (refereegranskat)abstract
- The present research focuses on the synergistic source control of particulate matter (PM) and NOx formation from pulverized coal combustion. Comparative experiments of preheating-combustion and conventional combustion were conducted in a lab-scale high-temperature preheating-combustion furnace, and PM10 and NO were measured by an electrical low pressure impactor and a flue gas analyzer, respectively. The results of the experiment indicate that preheating-combustion has a significant reduction in PM10 (especially PM0.3 up to 37.51 %) and NO, which can achieve the synergistic control of PM10 and NO source emissions during the combustion process. The fragmentation in preheating-combustion was weaker compared to the conventional combustion. Meanwhile, the relatively weak preheating-combustion coal char oxidation reaction leads to a decrease in ultrafine mode PM yielded due to the inhibition on vaporization of mineral inclusions. The PM0.3/PM1 mass ratio of the preheating-combustion has a decreasing trend, implying an elevated yield of PM0.3-1 and a shift of the average PM1 particle size toward a larger particle size. Higher preheating temperature (Tp) presented the potential to further reduce NO formation, and the NO reduction efficiency increased from 46.59 % to 56.60 % when the Tp was increased from 1200 K to 1600 K. All our preliminary results throw light on the nature of synergistic source control of preheating-combustion PM and NO formation.
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