| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Li, Wei, et al.
(författare)
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Non-lab and semi-lab algorithms for screening undiagnosed diabetes : A cross-sectional study
- 2018
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Ingår i: EBioMedicine. - : ELSEVIER SCIENCE BV. - 2352-3964. ; 35, s. 307-316
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Tidskriftsartikel (refereegranskat)abstract
- Background: The terrifying undiagnosed rate and high prevalence of diabetes have become a public emergency. A high efficiency and cost-effective early recognition method is urgently needed. We aimed to generate innovative, user-friendly nomograms that can be applied for diabetes screening in different ethnic groups in China using the non-lab or noninvasive semi-lab data. Methods: This multicenter, multi-ethnic, population-based, cross-sectional study was conducted in eight sites in China by enrolling subjects aged 20-70. Sociodemographic and anthropometric characteristics were collected. Blood and urine samples were obtained 2 h following a standard 75 g glucose solution. In the final analysis, 10,794 participants were included and randomized into model development (n - 8096) and model validation (n = 2698) group with a ratio of 3:1. Nomograms were developed by the stepwise binary logistic regression. The nomograms were validated internally by a bootstrap sampling method in the model development set and externally in the model validation set. The area under the receiver operating characteristic curve (AUC) was used to assess the screening performance of the nomograms. Decision curve analysis was applied to calculate the net benefit of the screening model. Results: The overall prevalence of undiagnosed diabetes was 9.8% (1059/10794) according to ADA criteria. The non-lab model revealed that gender, age, body mass index, waist circumference, hypertension, ethnicities, vegetable daily consumption and family history of diabetes were independent risk factors for diabetes. By adding 2 h post meal glycosuria qualitative to the non-lab model, the semi-lab model showed an improved Akaike information criterion (AIC: 4506 to 3580). The AUC of the semi-lab model was statistically larger than the non-lab model (0.868 vs 0.763, P < 0.001). The optimal cutoff probability in semi-lab and non-lab nomograms were 0.088 and 0.098, respectively. The sensitivity and specificity were 76.3% and 81.6%, respectively in semi-lab nomogram, and 72.1% and 673% in non-lab nomogram at the optimal cut off point. The decision curve analysis also revealed a bigger decrease of avoidable OGTT test (52 per 100 subjects) in the semi-lab model compared to the non-lab model (36 per 100 subjects) and the existed New Chinese Diabetes Risk Score (NCDRS, 35 per 100 subjects). Conclusion: The non-lab and semi-lab nomograms appear to be reliable tools for diabetes screening, especially in developing countries. However, the semi-lab model outperformed the non-lab model and NCDRS prediction systems and might be worth being adopted as decision support in diabetes screening in China.
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| 3. |
- Chen, Wei, et al.
(författare)
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Colloidal PbS quantum dot stacking kinetics during deposition via printing
- 2020
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Ingår i: Nanoscale Horizons. - : Royal Society of Chemistry (RSC). - 2055-6764 .- 2055-6756. ; 5:5, s. 880-885
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Tidskriftsartikel (refereegranskat)abstract
- Colloidal PbS quantum dots (QDs) are attractive for solution-processed thin-film optoelectronic applications. In particular, directly achieving QD thin-films by printing is a very promising method for low-cost and large-scale fabrication. The kinetics of QD particles during the deposition process play an important role in the QD film quality and their respective optoelectronic performance. In this work, the particle self-organization behavior of small-sized QDs with an average diameter of 2.88 +/- 0.36 nm is investigated for the first time in situ during printing by grazing-incidence small-angle X-ray scattering (GISAXS). The time-dependent changes in peak intensities suggest that the structure formation and phase transition of QD films happen within 30 seconds. The stacking of QDs is initialized by a templating effect, and a face-centered cubic (FCC) film forms in which a superlattice distortion is also found. A body-centered cubic nested FCC stacking is the final QD assembly layout. The small size of the inorganic QDs and the ligand collapse during the solvent evaporation can well explain this stacking behavior. These results provide important fundamental understanding of structure formation of small-sized QD based films prepared via large-scale deposition with printing with a slot die coater.
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| 4. |
- Guo, Renjun, et al.
(författare)
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Degradation mechanisms of perovskite solar cells under vacuum and one atmosphere of nitrogen
- 2021
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Ingår i: Nature Energy. - : Springer Nature. - 2058-7546. ; 6:10, s. 977-
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Tidskriftsartikel (refereegranskat)abstract
- Extensive studies have focused on improving the operational stability of perovskite solar cells, but few have surveyed the fundamental degradation mechanisms. One aspect overlooked in earlier works is the effect of the atmosphere on device performance during operation. Here we investigate the degradation mechanisms of perovskite solar cells operated under vacuum and under a nitrogen atmosphere using synchrotron radiation-based operando grazing-incidence X-ray scattering methods. Unlike the observations described in previous reports, we find that light-induced phase segregation, lattice shrinkage and morphology deformation occur under vacuum. Under nitrogen, only lattice shrinkage appears during the operation of solar cells, resulting in better device stability. The different behaviour under nitrogen is attributed to a larger energy barrier for lattice distortion and phase segregation. Finally, we find that the migration of excessive PbI2 to the interface between the perovskite and the hole transport layer degrades the performance of devices under vacuum or under nitrogen. Understanding degradation mechanisms in perovskite solar cells is key to their development. Now, Guo et al. show a greater degradation of the perovskite structure and morphology for devices operated under vacuum than under nitrogen.
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| 5. |
- He, Mao Qiang, et al.
(författare)
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Phylogenomics, divergence times and notes of orders in Basidiomycota
- 2024
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Ingår i: Fungal Diversity. - 1560-2745 .- 1878-9129. ; 126, s. 127-406
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Tidskriftsartikel (refereegranskat)abstract
- Basidiomycota is one of the major phyla in the fungal tree of life. The outline of Basidiomycota provides essential taxonomic information for researchers and workers in mycology. In this study, we present a time-framed phylogenomic tree with 487 species of Basidiomycota from 127 families, 47 orders, 14 classes and four subphyla; we update the outline of Basidiomycota based on the phylogenomic relationships and the taxonomic studies since 2019; and we provide notes for each order and discuss the history, defining characteristics, evolution, justification of orders, problems, significance, and plates. Our phylogenomic analysis suggests that the subphyla diverged in a time range of 443–490 Myr (million years), classes in a time range of 312–412 Myr, and orders in a time range of 102–361 Myr. Families diverged in a time range of 50–289 Myr, 76–224 Myr, and 62–156 Myr in Agaricomycotina, Pucciniomycotina, and Ustilaginomycotina, respectively. Based on the phylogenomic relationships and divergence times, we propose a new suborder Mycenineae in Agaricales to accommodate Mycenaceae. In the current outline of Basidiomycota, there are four subphyla, 20 classes, 77 orders, 297 families, and 2134 genera accepted. When building a robust taxonomy of Basidiomycota in the genomic era, the generation of molecular phylogenetic data has become relatively easier. Finding phenotypical characters, especially those that can be applied for identification and classification, however, has become increasingly challenging.
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| 6. |
- Li, B., et al.
(författare)
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Perspectives of energy transitions in East and Southeast Asia
- 2020
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Ingår i: Wiley Interdisciplinary Reviews. - : John Wiley and Sons Ltd. - 2041-8396 .- 2041-840X. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Energy transitions are designed to improve the resilience, sustainability, and productivity of a country's energy system, and are the key instruments to mitigating the warming climate. Countries and regions have unique circumstances when projecting energy transition pathways. Nonetheless, East Asian economies have shared opportunities and challenges. From the perspective of fuel mix, East Asia had some initial success in renewable energy development accompanied by energy efficiency improvements. Nuclear energy, although controversial, has been well developed and is continuing its advancement in East Asia. However, the dominance of coal in the energy mix has not been sufficiently addressed, mostly because of legacy issues. The region's renewable energy potential is also underdeveloped due to a mismatch between resources and energy demand. Since the region as whole is well endowed with renewable energy resources, the region's advancement in regional energy connectivity presents a valuable institutional asset to further decarbonize East Asian energy sector beyond individual nation's efforts. This article is categorized under: Energy and Climate > Economics and Policy Energy Policy and Planning > Economics and Policy Energy and Development > Economics and Policy.
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| 7. |
- Li, Y., et al.
(författare)
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A life cycle analysis techno-economic assessment framework for evaluating future technology pathways – The residential air-conditioning example
- 2021
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Ingår i: Applied Energy. - : Elsevier Ltd. - 0306-2619 .- 1872-9118. ; 291
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Tidskriftsartikel (refereegranskat)abstract
- Clarity on cost and environmental benefits of individual technologies evaluated in a systemic and systematic manner is necessary in communicating the results at the policy level so as to enable effective decisions. Yet, the highly complex nature of many energy modelling tools makes it difficult for non-specialists to interpret and make sense of their results. An integrated life cycle analysis and techno-economic assessment framework is proposed in this study, as a first step towards developing an alternative and potentially more intuitive energy systems modelling tool. The residential air-conditioning sector in the Southeast Asian context is used as an example to demonstrate the advantages of the modelling methodology in profiling future technology pathways. The use of best available R32 technology can lead to cumulative savings of 2195 million tonnes of greenhouse gas emissions in the region by 2050; while the best available R407C technology has an average cost of $40.85 per tonne of greenhouse gas abatement. In addition, our modelling tool is capable of profiling energy outlooks for emerging economies and will be further integrated with hourly energy analysis frameworks in the next steps of development.
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| 8. |
- Liu, S., et al.
(författare)
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Performance analysis of two-stage compression transcritical CO2 refrigeration system with R290 mechanical subcooling unit
- 2019
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Ingår i: Energy. - : Elsevier Ltd. - 0360-5442 .- 1873-6785. ; 189
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Tidskriftsartikel (refereegranskat)abstract
- The use of carbon dioxide (CO2) as refrigerant is driven by the need to phase down the traditional synthetic refrigerant so as to mitigate the warming climate. In this study, the thermal performance of a two-stage compression transcritical CO2 refrigeration system with R290 mechanical subcooling unit is conducted. The goal is to obtain the maximum coefficient of performance (COP) of five different mechanical subcooling systems under the optimal subcooling temperature and compressor discharge pressure. The two-throttling and two-stage compression high-pressure mechanical subcooling system is found to have a higher COP. When the evaporation temperature is −30 °C, the COP of the two-throttling and two-stage compression high-pressure mechanical subcooling system is improved by 76.74%. The COP of the two-throttling and two-stage compression high-pressure mechanical subcooling system is 1.52 at an ambient temperature of 40 °C, which is 21.87% higher than that of the two-throttling and two-stage compression low-pressure mechanical subcooling system. The power consumption ratio of one-throttling and two-stage compression low-pressure mechanical subcooling system is significantly higher than that of other systems. From a comprehensive analysis of the proposed four systems, the two-throttling and two-stage compression high-pressure mechanical subcooling system has the best performance over all other systems.
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| 9. |
- Yang, S., et al.
(författare)
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Economic feasibility of using fuel cells as backup power supply in data centers
- 2024
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Ingår i: Sustainable Energy Technologies and Assessments. - : Elsevier Ltd. - 2213-1388 .- 2213-1396. ; 69
-
Tidskriftsartikel (refereegranskat)abstract
- The backup power system (BPS) is essential to data centers (DCs) in case of grid outage. Currently, the diesel generator (DG) is the most commonly used solution. However, due to the need of decarbonization, fuel cells (FCs) are emerging as a promising alternative. This paper conducts a holistic economic analysis to investigate the benefit from using FCs to replace DGs, which takes into account more key impact factors. Different requirements by different Tiers of DCs, such as on the BPS runtime and the BPS test time, are considered. Under the benchmark condition, i.e. 800 USD/kW for the FC capital cost, 4.8 USD/kg, 1.25 USD/L and 90 USD/ton for hydrogen, diesel, and CO2 prices, the payback period is 13.4 years and 13.1 years when using FCs to replace DGs for Tier 1–2 DCs and Tier 3 DCs. Since Tier 4 DCs require more units, FCs can be economically feasible if the FC capital cost reduces by 20.3 %, the diesel price increases by 19.7 %, or the green hydrogen price decreases by 35.5 %, compared to the benchmark conditions. Among the factors, the FC capital cost, the diesel price, and the hydrogen price are found to affect the payback period mostly.
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| 10. |
- Yang, S., et al.
(författare)
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Economics of marinised offshore charging stations for electrifying the maritime sector
- 2022
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Ingår i: Applied Energy. - : Elsevier Ltd. - 0306-2619 .- 1872-9118. ; 322
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Tidskriftsartikel (refereegranskat)abstract
- Electrification of international maritime transport, despite rapidly falling battery prices and improvements in battery technologies, remains constrained by midway charging, as the range of electric ocean-going vehicles is limited on a full charge. Before countries pour trillions of dollars of investment, this study is commissioned as the first attempt to investigate the economics of offshore marinised charging stations for enabling long-distance shipping by full-electric vessels. Three offshore power generation technologies, namely, wind, solar, and floating nuclear power plants, are compared to demonstrate the economics of offshore charging stations. Compared to conventional vessels using bunker fuels, full-electric vessels are cost competitive even under the assumed first-of-a-kind costs. Among the three offshore power sources compared in this study, a marinised charging station with floating nuclear power plant is shown to be the most cost-competitive. Despite the absence of a pilot project, the technoeconomic parameters as assumed in this study serve as important reference indicators for decision makers to consider when building an ecosystem for sustainable international shipping. © 2022 Elsevier Ltd
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| 11. |
- Chen, Wei, et al.
(författare)
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In situ Grazing-Incidence Small-Angle X-ray Scattering Observation of Gold Sputter Deposition on a PbS Quantum Dot Solid
- 2020
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Ingår i: ACS Applied Materials and Interfaces. - : NLM (Medline). - 1944-8244 .- 1944-8252. ; 12:41, s. 46942-46952
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Tidskriftsartikel (refereegranskat)abstract
- For PbS quantum dot (QD)-based optoelectronic devices, gold is the most frequently used electrode material. In most device architectures, gold is in direct contact with the QD solid. To better understand the formation of the interface between gold and a close-packed QD layer at an early stage, in situ grazing-incidence small-angle X-ray scattering is used to observe the gold sputter deposition on a 1,2-ethanedithiol (EDT)-treated PbS QD solid. In the kinetics of gold layer growth, the forming and merging of small gold clusters (radius less than 1.6 nm) are observed at the early stages. The thereby formed medium gold clusters (radius between 1.9-2.4 nm) are influenced by the QDs' templating effect. Furthermore, simulations suggest that the medium gold clusters grow preferably along the QDs' boundaries rather than as a top coating of the QDs. When the thickness of the sputtered gold layer reaches 6.25 nm, larger gold clusters with a radius of 5.3 nm form. Simultaneously, a percolation layer with a thickness of 2.5 nm is established underneath the gold clusters. This fundamental understanding of the QD-gold interface formation will help to control the implementation of sputtered gold electrodes on close-packed QD solids in device manufacturing processes.
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| 12. |
- Gensch, Marc, et al.
(författare)
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Correlating Optical Reflectance with the Topology of Aluminum Nanocluster Layers Growing on Partially Conjugated Diblock Copolymer Templates
- 2021
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 13:47, s. 56663-56673
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Tidskriftsartikel (refereegranskat)abstract
- Large-scale fabrication of metal cluster layers for usage in sensor applications and photovoltaics is a huge challenge. Physical vapor deposition offers large-scale fabrication of metal cluster layers on templates and polymer surfaces. In the case of aluminum (Al), only little is known about the formation and interaction of Al clusters during sputter deposition. Complex polymer surface morphologies can tailor the deposited Al cluster layer. Here, a poly(methyl methacrylate)-block-poly(3-hexylthiophen-2,5-diyl) (PMMA-b-P3HT) diblock copolymer template is used to investigate the nanostructure formation of Al cluster layers on the different polymer domains and to compare it with the respective homopolymers PMMA and P3HT. The optical properties relevant for sensor applications are monitored with ultraviolet-visible (UV-vis) measurements during the sputter deposition. The formation of Al clusters is followed in situ with grazing-incidence small-angle X-ray scattering (GISAXS), and the chemical interaction is revealed by X-ray photoelectron spectroscopy (XPS). Furthermore, atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) yield topographical information about selective wetting of Al on the P3HT domains and embedding in the PMMA domains in the early stages, followed by four distinct growth stages describing the Al nanostructure formation.
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| 13. |
- Gensch, Marc, et al.
(författare)
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Selective Silver Nanocluster Metallization on Conjugated Diblock Copolymer Templates for Sensing and Photovoltaic Applications
- 2021
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Ingår i: ACS Applied Nano Materials. - : American Chemical Society (ACS). - 2574-0970. ; 4:4, s. 4245-4255
-
Tidskriftsartikel (refereegranskat)abstract
- Polymer-metal composite films with nanostructured metal and/or polymer interfaces show a significant perspective for optoelectronic applications, for example, as sensors or in organic photovoltaics (OPVs). The polymer components used in these devices are mostly nanostructured conductive polymers with conjugated pi-electron systems. Enhanced OPV's power conversion efficiencies or sensor sensitivity can be achieved by selective metal deposition on or into polymer templates. In this study, we exploit time-resolved grazing-incidence X-ray scattering to observe the metal-polymer interface formation and the cluster crystallite size in situ during silver (Ag) sputter deposition on a poly(3-hexylthiophene-2,5-diyl)-b-poly(methyl methacrylate) (PMMA-b-P3HT) template. We compare the arising nanoscale morphologies with electronic properties, determine Ag growth regimes, and quantify the selective Ag growth for the diblock copolymer (DBC) template using the corresponding homopolymer thin films (P3HT and PMMA) as a reference. Hence, we are able to describe the influence of the respective polymer blocks and substrate effects on the Ag cluster percolation: the percolation threshold is correlated with the insulator-to-metal transition measured in situ with resistance measurements during the sputter deposition. The Ag cluster percolation on PMMA-b-P3HT starts already on the network of the hexagonal P3HT domain before a complete metal film covers the polymer surface, which is complemented by microscopic measurements. In general, this study demonstrates a possible method for the selective Ag growth as a scaffold for electrode preparation in nanoelectronics and for energy harvesting applications.
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| 14. |
- Li, Long, et al.
(författare)
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Discriminative Co-Saliency and Background Mining Transformer for Co-Salient Object Detection
- 2023
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Ingår i: 2023 IEEE/CVF CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION, CVPR. - : IEEE COMPUTER SOC. - 9798350301298 - 9798350301304 ; , s. 7247-7256
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Konferensbidrag (refereegranskat)abstract
- Most previous co-salient object detection works mainly focus on extracting co-salient cues via mining the consistency relations across images while ignore explicit exploration of background regions. In this paper, we propose a Discriminative co-saliency and background Mining Transformer framework (DMT) based on several economical multi-grained correlation modules to explicitly mine both co-saliency and background information and effectively model their discrimination. Specifically, we first propose a region-to-region correlation module for introducing inter-image relations to pixel-wise segmentation features while maintaining computational efficiency. Then, we use two types of pre-defined tokens to mine co-saliency and background information via our proposed contrast-induced pixel-to-token correlation and co-saliency token-to-token correlation modules. We also design a token-guided feature refinement module to enhance the discriminability of the segmentation features under the guidance of the learned tokens. We perform iterative mutual promotion for the segmentation feature extraction and token construction. Experimental results on three benchmark datasets demonstrate the effectiveness of our proposed method. The source code is available at: https://github.com/dragonlee258079/DMT.
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| 15. |
- Li, Long, et al.
(författare)
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Robust Perception and Precise Segmentation for Scribble-Supervised RGB-D Saliency Detection
- 2024
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Ingår i: IEEE Transactions on Pattern Analysis and Machine Intelligence. - : IEEE COMPUTER SOC. - 0162-8828 .- 1939-3539. ; 46:1, s. 479-496
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes a scribble-based weakly supervised RGB-D salient object detection (SOD) method to relieve the annotation burden from pixel-wise annotations. In view of the ensuing performance drop, we summarize two natural deficiencies of the scribbles and try to alleviate them, which are the weak richness of the pixel training samples (WRPS) and the poor structural integrity of the salient objects (PSIO). WRPS hinders robust saliency perception learning, which can be alleviated via model design for robust feature learning and pseudo labels generation for training sample enrichment. Specifically, we first design a dynamic searching process module as a meta operation to conduct multi-scale and multi-modal feature fusion for the robust RGB-D SOD model construction. Then, a dual-branch consistency learning mechanism is proposed to generate enough pixel training samples for robust saliency perception learning. PSIO makes direct structural learning infeasible since scribbles can not provide integral structural supervision. Thus, we propose an edge-region structure-refinement loss to recover the structural information and make precise segmentation. We deploy all components and conduct ablation studies on two baselines to validate their effectiveness and generalizability. Experimental results on eight datasets show that our method outperforms other scribble-based SOD models and achieves comparable performance with fully supervised state-of-the-art methods.
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| 16. |
- Li, Nian, et al.
(författare)
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In Situ Study of Order Formation in Mesoporous Titania Thin Films Templated by a Diblock Copolymer during Slot-Die Printing
- 2020
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 12:51, s. 57627-57637
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Tidskriftsartikel (refereegranskat)abstract
- Slot-die printing, a large-scale deposition technique, is applied to fabricate mesoporous titania films. Printing is interesting, for example, for scaling up solar cells where titania films with an interconnected mesoporous network and a large surface-to-volume ratio are desired as photoanodes. A fundamental understanding of the structure evolution during printing is of high significance in tailoring these films. In this work, we provide important insights into the self-assembly of the slot-die-printed titania/polystyrene-block-poly(ethylene oxide) (PS-b-PEO) micelles into ordered hybrid structures in real time via in situ grazing-incidence small-angle X-ray scattering (GISAXS). GISAXS allows for tracking both vertical and lateral structure development of the film formation process. In the hybrid film, a face-centered cubic (FCC) structure is preferentially formed at the interfaces with air and with the substrate, while a defect-rich mixed FCC and bodycentered cubic (BCC) structure forms in the bulk. After calcination, the surface and inner morphologies of the obtained nanostructured titania films are compared with the spin-coated analogues. In the printed films, the initially formed nanoscale structure of the hybrid film is preserved, and the resulting mesoporous titania film shows a superior order as compared with the spincoated thin films which can be beneficial for future applications.
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| 17. |
- Li, Nian, et al.
(författare)
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Morphology Phase Diagram of Slot-Die Printed TiO2 Films Based on Sol-Gel Synthesis
- 2019
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Ingår i: Advanced Materials Interfaces. - : WILEY. - 2196-7350. ; 6:12
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Tidskriftsartikel (refereegranskat)abstract
- Mesoporous titania films with tailored nanostructures are fabricated via slot-die printing, which is a simple and cost-effective thin-film deposition technique with the possibility of a large-scale manufacturing. Based on this technique, which is favorable in industry, TiO2 films possess the similar advantage with polymer semiconducting devices like ease of large-scale production. The titania morphologies, including foam-like nanostructures, nanowire aggregates, collapsed vesicles and nanogranules, are achieved via a so-called block-copolymer-assisted sol-gel synthesis. By adjusting the weight fraction of reactants, the ternary morphology phase diagram of the printed titania films is probed after template removal. The surface and inner morphology evolutions are explored with scanning electron microscopy and grazing incidence small-angle X-ray scattering, respectively. Special focus is set on foam-like titania nanostructures as they are of especial interest for, e.g., solar cell applications. At a low weight fraction of the titania precursor titanium(IV)isopropoxide (TTIP), foam-like titania films are achieved, which exhibit a high uniformity and possess large pore sizes. The anatase phase of the highly crystalline titania films is verified with X-ray diffraction and transmission electron microscopy.
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| 18. |
- Liu, Shengchun, et al.
(författare)
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Alternative positions of internal heat exchanger for CO2 booster refrigeration system : Thermodynamic analysis and annual thermal performance evaluation
- 2021
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Ingår i: International journal of refrigeration. - : ELSEVIER SCI LTD. - 0140-7007 .- 1879-2081. ; 131, s. 1016-1028
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Tidskriftsartikel (refereegranskat)abstract
- Refrigeration systems running on transcritical CO2 cycle are considered an alternative to phase-down the use of hydrofluorocarbons (HFCs) in response to the Kigali Amendment. Responding to the need to improve the efficiency of CO2 booster systems and to identify optimum system designs, thermodynamic models of three booster systems are proposed with the use of an internal heat exchanger (IHX). Findings from this study suggest that placing the IHX with a low-temperature fluid side at the suction line of high pressure stage compressor and high-temperature fluid side at the outlet of gas cooler represents the most optimal approach in improving the coefficient of performance (COP) of the booster system. When operating in the transcritical conditions, the COP values can be improved by 6.35% at the IHX thermal effectiveness of 0.8 and by 6.48% at the ratio of medium temperature load to low temperature load of 6. Using IHX can significantly reduce the compressor discharge pressure, which can be reduced by 0.55 MPa at the ambient temperature of 40 degrees C. Furthermore, by adding IHX, the annual performance factor of CO2 system can be improved significantly by 1.68% and the annual total power consumption can be decreased by 6.48% in the tropical climate. It can be concluded that IHX can improve the COP values of a booster system when operating in the subtropical and tropical regions.
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| 19. |
- Nian, V., et al.
(författare)
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A Comparative Cost Assessment of Energy Production from Central Heating Plant or Combined Heat and Power Plant
- 2016
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; , s. 556-561
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Konferensbidrag (refereegranskat)abstract
- The levelized cost of electricity (LCOE) is a common approach in evaluating the economic competitiveness of a power generation technology. The same approach can be applied for evaluating the levelized cost of heat (LCOH) production. There are a number of approaches in calculating the LCOE and or LCOH from a combined heat and power (CHP) plant. In this study, we explore three alternative methods in calculating the LCOE and LCOH of a CHP and compare the results with that those of a heating only plant. The results can be used as indicators for identifying a suitable pricing mechanisms for the heating market.
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| 20. |
- Nian, V., et al.
(författare)
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A feasibility study on integrating large-scale battery energy storage systems with combined cycle power generation – Setting the bottom line
- 2019
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Ingår i: Energy. - : Elsevier Ltd. - 0360-5442 .- 1873-6785. ; 185, s. 396-408
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Tidskriftsartikel (refereegranskat)abstract
- Strong attention has been given to the costs and benefits of integrating battery energy storage systems (BESS) with intermittent renewable energy systems. What's neglected is the feasibility of integrating BESS into the existing fossil-dominated power generation system to achieve economic and environmental objectives. In response, a life cycle cost-benefit analysis method is introduced in this study taking into consideration three types of battery technologies, namely, vanadium redox flow battery, zinc bromine flow battery, and lithium-iron-phosphate battery. The objective is to evaluate the life cycle carbon emissions and cost of electricity production by combined cycle power generation with grid-connected BESS. Findings from the Singapore case study suggest a potential 3–5% reduction in the life cycle carbon emission factors which could translate to a cumulative carbon emission reduction of 9–16 million tonnes from 2018 to 2030 from electricity generation. Grid-connected BESS could reduce the levelized cost of electricity by 4–7%. A synergistic planning of CCGT and BESS could theoretically reduce the system level power generation capacity by 26% albeit a potential increase in the overall capital cost at the current cost of batteries. The projected battery cost reduction is critical in improving the feasibility of large-scale deployment.
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| 21. |
- Sun, Xu, et al.
(författare)
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Chinese Herbal Medicine as Adjunctive Therapy to Chemotherapy for Breast Cancer : A Systematic Review and Meta-Analysis
- 2016
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Ingår i: Evidence-based Complementary and Alternative Medicine. - : Hindawi Limited. - 1741-427X .- 1741-4288.
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Forskningsöversikt (refereegranskat)abstract
- Chinese herbal medicine (CHM) has been increasingly employed during therapy for breast cancer, but its efficacy remains a matter of debate. This systematic review examined randomized controlled trials to provide a critical evaluation of this treatment. The results demonstrated that the combined use of CHM with chemotherapy may improve the immediate tumor response and reduce chemotherapy-associated adverse events. Our findings highlight the poor quality of Chinese studies, and additional well-designed randomized controlled trials addressing the role of CHM are warranted. The lack of molecular-based evidence for CHM and Zheng has resulted in a limited understanding and acceptance of CHM and traditional Chinese medicine in Western countries. We believe that researchers should immediately explore a CHM-based cure, and CHM should be applied to routine care as soon as conclusive data are available.
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| 22. |
- Sun, Xu, et al.
(författare)
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Elevated heparanase expression is associated with poor prognosis in breast cancer : a study based on systematic review and TCGA data
- 2017
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Ingår i: Oncotarget. - : IMPACT JOURNALS LLC. - 1949-2553. ; 8:26, s. 43521-43535
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Forskningsöversikt (refereegranskat)abstract
- Heparanase promotes tumorigenesis, angiogenesis, and metastasis. Here, we conducted a study based on systematic review and the Cancer Genome Atlas (TCGA) data that examined heparanase expression in clinical samples to determine its prognostic value. According to the meta-analysis and TCGA data, we found that heparanase expression was up-regulated in most breast cancer specimens, and elevated heparanase expression was associated with increased lymph node metastasis, larger tumor size, higher histological grade, and poor survival. These results suggest that targeting heparanase might improve treatments for breast cancer patients.
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| 23. |
- Tu, Suo, et al.
(författare)
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Improvement of the thermoelectric properties of PEDOT:PSS films via DMSO addition and DMSO/salt post-treatment resolved from a fundamental view
- 2022
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 429
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Tidskriftsartikel (refereegranskat)abstract
- The combination of dimethyl sulfoxide (DMSO)-solvent doping and physical-chemical DMSO/salt de-doping in a sequence has been used to improve the thermoelectric (TE) properties of poly(3,4-ethylenedioxythiophene):poly (4-styrenesulfonate) (PEDOT:PSS) films. A high power factor of ca.105.2 mu W m(-1) K-2 has been achieved for the PEDOT:PSS film after post-treatment with 10 % sodium sulfite (Na2SO3) in the DMSO/salt mixture (v/v), outperforming sodium bicarbonate (NaHCO3). The initial DMSO-doping treatment induces a distinct phase separation by facilitating the aggregation of the PEDOT molecules. At the same time, the subsequent DMSO/salt dedoping post-treatment strengthens the selective removal of the surplus non-conductive PSS chains. Substantial alterations in the oxidation level, chain conformations, PEDOT crystallites and their preferential orientation are observed upon treatment on the molecular level. At the mesoscale level, the purification and densification of PEDOT-rich domains enable the realization of inter-grain coupling by the formation of the electronically well-percolated network. Thereby, both electrical conductivity and Seebeck coefficient are optimized.
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| 24. |
- Wang, F., et al.
(författare)
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Do ‘green’ data centres really have zero CO2 emissions?
- 2022
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Ingår i: Sustainable Energy Technologies and Assessments. - : Elsevier Ltd. - 2213-1388 .- 2213-1396. ; 53
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Tidskriftsartikel (refereegranskat)abstract
- The claim of a green data centre is generally made based on a net-zero CO2 emission through a ‘balance-sheet’ approach, which considers renewable electricity through on-site installation or purchase agreement as abatement measures against the use of fossil electricity from the electric grid on an annual basis. However, when the hourly dynamic fuel mix is accounted for in the assessment, the annual net-zero energy approach does not lead to a true carbon neutral data centre. In response, two approaches based on net-zero energy and net-zero CO2 emission respectively are proposed and investigated regarding the goal of net-zero CO2 emission. A data centre in Singapore with typical load profiles is used as a case study, different scenarios considering climate change and projected future energy are defined to examine the impacts of dynamic energy mix on the net CO2 emission of the data centre. The net-zero energy approach is found to result in significant amount of annual CO2 emissions. In comparison, the net-zero CO2 emission approach can assure a true net-zero CO2 emission, but this approach will require an increase of PV capacity by 20% and 60% as compared to the net-zero energy approach based on assessment for the year 2030 and 2050, respectively.
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| 25. |
- Wang, L., et al.
(författare)
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Impacts of electric vehicle deployment on the electricity sector in a highly urbanised environment
- 2021
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 95
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Tidskriftsartikel (refereegranskat)abstract
- The developments in electric vehicles (EVs) are driven by the need for cleaner and more efficient road transport, but vehicle charging poses significant challenges to the electric grid and electricity sector planning. These challenges are further amplified in the case of a highly urbanised and densely populated small island state, like Singapore, with limited space and options for electricity sector planning. In response, this study aims to evaluate the impacts of a large-scale EV deployment on the electricity sector from a whole-system perspective with focus on investments in the power sector for EV adoption, assuming minimum deployment of advanced “smart-grid” and “vehicle-to-grid” technologies. Findings suggest that a small-scale deployment of EVs below 20% replacement can be economically manageable. A large-scale of deployment of EVs would inevitably bring a notable impact to the electricity sector regardless the state of advanced technology development. From the perspective of integrated planning, cities, especially those with high vehicle density, should continue to exercise caution with EV deployment. A large-scale deployment should be pursued after a “stress-test” of the power system infrastructure from both the technical and economic perspectives.
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| 26. |
- Wang, Y., et al.
(författare)
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Life cycle analysis of integrated gasification combined cycle power generation in the context of Southeast Asia
- 2018
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 11:6
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Tidskriftsartikel (refereegranskat)abstract
- Coal remains a major source of electricity production even under the current state of developments in climate policies due to national energy priorities. Coal remains the most attractive option, especially to the developing economies in Southeast Asia, due to its abundance and affordability in the region, despite the heavily polluting nature of this energy source. Gasification of coal running on an integration gasification combined cycle (IGCC) power generation with carbon capture and storage (CCS) represents an option to reduce the environmental impacts of power generation from coal, but the decarbonization potential and suitability of IGCC in the context of Southeast Asia remain unclear. Using Singapore as an example, this paper presents a study on the life cycle analysis (LCA) of IGCC power generation with and without CCS based on a generic process-driven analysis method. We further evaluate the suitability of IGCC with and without CCS as an option to address the energy and climate objectives for the developing economies in Southeast Asia. Findings suggest that the current IGCC technology is a much less attractive option in the context of Southeast Asia when compared to other available power generation technologies, such as solar photovoltaic systems, coal with CCS, and potentially nuclear power technologies.
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| 27. |
- Wu, S., et al.
(författare)
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The state of the art on preheating lithium-ion batteries in cold weather
- 2020
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Ingår i: Journal of Energy Storage. - : Elsevier Ltd. - 2352-152X .- 2352-1538. ; 27
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Forskningsöversikt (refereegranskat)abstract
- Preheating batteries in electric vehicles under cold weather conditions is one of the key measures to improve the performance and lifetime of lithium-ion batteries. In general, preheating can be divided into external heating and internal heating, depending on the location of the heat source. External heating methods are usually characterized by low system complexity, long heating time and high energy loss; while internal heating methods can achieve a shorter heating time, a higher heating efficiency and lower impacts on thermal-induced aging but at a higher risk in safety. Through reviewing recent progress in the development of preheating methods for lithium-ion batteries, this paper provides insights on developing new preheating techniques and guidance on the selection of preheating methods.
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| 28. |
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| 29. |
- Yin, Shanshan, et al.
(författare)
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Multidimensional Morphology Control for PS-b-P-4 VP Templated Mesoporous Iron (III) Oxide Thin Films
- 2021
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Ingår i: Advanced Materials Interfaces. - : Wiley. - 2196-7350. ; 8:14
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Tidskriftsartikel (refereegranskat)abstract
- Mesoporous alpha-Fe2O3 thin films with large area homogeneity demonstrate tremendous potential in multiple applications. In the present work, the synthesis of morphology-controlled alpha-Fe2O3 thin films is realized with polystyrene-block-poly(4-vinyl pyridine) (PS-b-P4VP) diblock copolymer assisted sol-gel chemistry. The solvent category (DMF and 1,4-dioxane) and polymer-to-FeCl3 ratio used for the solution preparation are systematically varied to tune the morphology of the thin films. For both solvents, DMF and 1,4-dioxane, nanocluster structures are obtained with low PS-b-P4VP concentration. When the concentration of PS-b-P4VP reaches the critical micelle concentration, spherical and wormlike porous structures are specifically formed in the DMF and 1,4-dioxane solvent system, respectively. Further increasing the polymer-to-FeCl3 ratios leads to the enlargement of the spherical pore sizes in the DMF system, whereas the center-to-center distances of the wormlike structures in the 1,4-dioxane system decrease. Moreover, DMF/1,4-dioxane solvent mixtures with different volume ratios are applied for the sol-gel solution preparation to gain more insight into how the solvent selectivity affects the thin film morphology. By adjusting the preferential affinity of the solvent mixture to the polymer blocks, a spherical to wormlike pore shape transition is observed with a critical Delta chi value of around 0.77.
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