| 1. |
- Liu, Daosheng, et al.
(author)
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Investigation on heating aging mechanism of cellulose paper for oil-immersed transformer main insulation
- 2019
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In: Proceedings - IEEE International Conference on Dielectric Liquids. - 2153-3733 .- 2153-3725. ; 2019-June:June
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Conference paper (peer-reviewed)abstract
- Power transformer plays a vital role in maintaining reliable and efficient electricity supply. However, in service is increasing and growing older, much and much attention has been paid on their aging condition and life assessment than ever. The aging and degradation of transformer insulation will determine the life-time of its operation. The intensities of these depend on mechanical, thermal and environmental stresses that act on the insulations. Due to the temperature rise, the lifetime of insulation material will be shortened. The accelerated thermal aging method is often adopted to do some evaluation on the oil-paper insulation materials under different temperature for the thermal lifetime model. According to existing aging test, both insulation paper and mineral oil were aged at the same temperature. In this paper, the thermal aging experiments were implemented on the transformer main insulation model made with modified and unmodified insulation paper. The accelerated thermal aging tests were finished, and the superior electric characteristics of the nano-TiO2 and cellulose composition insulation were validated.
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| 2. |
- Liu, Daosheng, et al.
(author)
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Suppression Mechanism of TiO 2 for the Partial Discharge of Oil-paper Insulation in Intensive Electric Field
- 2019
-
In: Proceedings - IEEE International Conference on Dielectric Liquids. - 2153-3733 .- 2153-3725. ; 2019-June
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Conference paper (peer-reviewed)abstract
- With the rapid development of modern HVDC transmission technology, higher insulation properties are put forward on the oil-paper insulation system of the transformer, which determine the transformer service life to a certain extent. Traditional transformer oil-paper insulation is becoming increasingly difficult to meet the demands of insulation system with large capacity and miniaturization at ultra-high voltage level. In order to improve the insulation strength of oil-paper system, the insulation cellulose paper modified by TiO2 nanoparticles of different diameters (5 nm, 10 nm, 20 nm, 30 nm) were prepared, in addition, each of modified cellulose paper has different mass fraction of TiO2 nanoparticles (1%, 3%, 5%, 7% wt.). The partial discharge (PD) detection platform was established, and the partial discharge inception voltage (PDIV) values of the oil-paper insulation system with and without nanoparticles were measured. To investigate the PD characteristics, the PD waveforms and PD frequency spectrums of modified cellulose paper and the unmodified were obtained. The suppression mechanism of TiO2 nanoparticles on PD was explored through scanning electron microscope (SEM) observation. All the experiment results indicate that adding nano-TiO2 is beneficial to enhance the insulation properties of oil-paper insulation, and the optimum diameter and mass fraction of TiO2 nanoparticles to suppress oil-paper PD were obtained.
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| 3. |
- Allgurén, Thomas, 1986, et al.
(author)
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The Influence of Alkali, Chlorine and Sulfur on Aerosol Formation
- 2019
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Conference paper (other academic/artistic)abstract
- The use of low-quality fuels in power generation is typically motivated by a potential reduction in fuel costs or CO2 emissions, the latter in case the fuel is based on biomass. These features make low quality fuels attractive at the same time as such fuels are usually problematic to use in power generation due to fuel composition. One of the main issues is deposition of aerosols upon heating surfaces reducing heat transfer and causing high-temperature corrosion (HTC). The later most often related to alkali chlorides, and these are formed from alkali species and chlorine when released during the combustion process. The present work aims to investigate how the gas phase chemistry are connected to the formation aerosols and their characteristics. This is an ongoing work why only part of the preliminary results is presented focusing on the interaction between alkali, sulfur and chlorine in the gas phase. The results presented here indicate a clear correlation between the S/Cl ratio and the formation of alkali sulfates over chlorides. It is also indicated that the local conditions at which the species are released and available in the gas phase is important for the resulting formation of alkali sulfates.
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| 4. |
- Fry, Andrew, et al.
(author)
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The influence of fuel composition on sulfation and deposition rates of alkali salts
- 2018
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In: CLEARWATER CLEAN ENERGY CONFERENCE 2018. - 9781510867666
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Conference paper (peer-reviewed)abstract
- The present work is based on recent pilot-scale experiments that examines the behavior of alkali, chlorine and sulfur containing aerosols during both air- and oxy-combustion conditions. The experiments have been performed at University of Utah where solid fuel experiments were performed in a 100kW combustion unit. The experiments focus on the formation of depositing ash particulates. The results from these experiments are then compared to chemical reaction kinetics simulations that allows for a more detailed investigation of the gas phase chemistry and its influence on the ash composition. The work aims to improve the understanding of how the ash composition and its deposit rate depends on the fuel composition and combustion conditions. The results show that the temperature is an important parameter for the aerosol formation influencing both composition and particle size distribution. The simulations also indicate that the amount of sulfur and chlorine in relation to potassium is important for the sulfation of potassium.
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| 5. |
- Li, Andol X., et al.
(author)
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Improving the User Engagement in Large Display Using Distance-Driven Adaptive Interface
- 2016
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In: Interacting with computers. - : Oxford University Press (OUP). - 0953-5438 .- 1873-7951. ; 28:4, s. 462-478
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Journal article (peer-reviewed)abstract
- Current large display-based user interfaces are mainly derived from normal-sized desktop screens and the extra-large size causes difficulties in information navigation and perception. Therefore, user engagement in large display-based information interaction is relatively low. In order to address the user engagement issue, in this paper we propose the distance-driven adaptive interface, which specialises in performing navigation tasks within large displays. We conducted an initial exploratory study with 30 participants to examine how the distance correlated with interaction performances in large displays. Given the findings we conducted an experimental study with an additional 31 participants to further investigate how the distance-driven interface satisfies users' distance requirements and improves user engagement within six dimensions. The results show that the distance-driven interface offered a statistically significant user engagement improvement in terms of novelty, felt involvement, focused attention and endurability. Importantly, linear correlations between the distance, interaction efficiency and accuracy were identified-in that efficiency increased and accuracy decreased with increasing distance.
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| 6. |
- Li, Andol X., et al.
(author)
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On the Influence of Distance in the Interaction With Large Displays
- 2016
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In: IEEE/OSA Journal of Display Technology. - 1551-319X .- 1558-9323. ; 12:8, s. 840-850
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Journal article (peer-reviewed)abstract
- As reported by a recent survey, over half of large display purchases are conducted for productivity purposes, while the remainder are purchased for a variety of purposes such as gaming and advertising. These large displays have advanced visibility, scalability, and accessibility characteristics and thus benefit perceived usability. However, usability issues such as the difficulties in precisely accessing distal information on large displays while on the move are still of concern. Therefore, in this paper, we investigate the influence of moving distance on perceived usability in interactions with large displays. Comparative study results show inconsistent perceived usability throughout a range of distances, which differs from standard usability conventions. Moreover, the results show a correlation between distance and perceived usability in that, as the distance from commonly visited ranges increases, the perceived usability level decreases, and vice versa. The study demonstrates that distance is an effective interaction modality in large-display interactions, although it has weaknesses such as limited input channels.
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| 7. |
- Li, Jiuyi, et al.
(author)
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Individual Assignment of Adult Diffuse Gliomas into the EM/PM Molecular Subtypes Using a TaqMan Low-Density Array.
- 2019
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In: Clinical cancer research : an official journal of the American Association for Cancer Research. - 1078-0432. ; 25:23, s. 7068-7077
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Journal article (peer-reviewed)abstract
- We aimed to develop a diagnostic platform to capture the transcriptomic resemblance of individual adult diffuse gliomas of WHO grades II-IV to neural development and the genomic signature associated with glioma progression.Based on the EM/PM classification scheme, we designed a RT-PCR-based TaqMan Low-density array (TLDA) containing 44 classifier and 4 reference genes. Samples of a training data set (GSE48865), characterized by RNA-sequencing, were utilized to optimize the TLDA design and to develop a support vector machine (SVM)-based prediction model. Complemented with Sanger sequencing for IDH1/2, and low coverage whole genome sequencing (WGS), the TLDA and SVM prediction model were tested in a validation (31 gliomas) and a test (121 gliomas) dataset.Independent of morphologically defined subtypes and grades, gliomas can be individually assigned into the EM and PM glioma subtypes with the respective areas under ROC curves at 0.86 and 0.85 in the validation dataset. The EM gliomas showed a medium overall survival (OS) of 15.6 months, whereas the medium OS for PM gliomas was not reached (hazard ratio = 3.55, 95% confidence interval: 1.96 to 6.45). The EM and PM gliomas showed distinct patterns of genomic alterations, with IDH mutation and 1p19q co-deletion in the PM gliomas and gain of chromosome 7/loss of chromosome 10 in the EM gliomas. Extensive chromosomal abnormalities marked the progression of PM gliomas.The integration of EM/PM subtyping, IDH sequencing and low coverage WGS may improve the risk stratification and selection of treatment regimens for glioma patients.
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| 8. |
- Li, Xiangdong A., et al.
(author)
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Design and Evaluation of Cross-Objects User Interface for Whiteboard Interaction
- 2017
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In: Distributed, Ambient and Pervasive Interactions. - Cham : Springer. - 9783319586960 - 9783319586977 ; , s. 180-191
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Conference paper (peer-reviewed)abstract
- Whiteboard has long been an important tool for education and communication, and nowadays it embraces display functions and other interactive features such as pen pointing and selecting of digital contents. Despite the enhanced interactivity, it is often time- and cost-consuming to implement specific apparatus for different whiteboard interactions. Therefore, we aimed at incorporating physical-world objects (e.g. Lego Rubik’s cubes) as the cross-objects user interface for multiple whiteboard interaction tasks without incurring heavy development work. The user interface utilised electromagnetic technique to extract electromechanical signals and recognised normal objects, thus extended the generality. To further understand effectiveness of the user interface, we implemented a low-fidelity prototype and conducted within-subject evaluation. The results showed the cross-objects user interface was natural, responsive, and easy of learning as the conventional whiteboard. Moreover, the user interface outperformed over the conventional one in the perspectives of configuration efficiency and versatility of multiple interaction tasks. Given these findings, practical implications for future tangible user interface design for whiteboard interactions are discussed.
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| 9. |
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| 10. |
- Liu, Alei, et al.
(author)
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Manipulate Micrometer Surface and Nanometer Bulk Phase Separation Structures in the Active Layer of Organic Solar Cells via Synergy of Ultrasonic and High-Pressure Gas Spraying
- 2019
-
In: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 11:11, s. 10777-10784
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Journal article (peer-reviewed)abstract
- For organic solar cells, the vertical and lateral micro-/nanometer-scale structure in the active layer largely determines the device performance. In this work, the surface and bulk domain size of the photoactive layer are successfully manipulated with a facile two-step spraying method, that is, an ultrathin active layer by high-pressure spraying is deliberately stacked on top of the thick active layer by ultrasonic spraying. Thus, the morphology is effectively optimized with the comprehensive study of optical and electrical characteristics, such as photon absorption, exciton dissociation efficiency, and bimolecular recombination. Moreover, the novel method can be used not only in the fullerene system but also in the nonfullerene system, demonstrating the remarkable universality through this synergy method. This work provides an easy and reliable strategy to improve photovoltaic device performance in the industrial large-area spray-coating process.
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| 11. |
- Lou, Xiaolong, et al.
(author)
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Optimizing Free Hand Selection in Large Displays by Adapting to User’s Physical Movements
- 2016
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In: Proceedings of the 2016 Symposium on Spatial User Interaction. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450340687 ; , s. 23-31
-
Conference paper (peer-reviewed)abstract
- Advance in motion sensing technologies such as Microsoft Kinect and ASUS Xtion has enabled users to select targets on a large display through natural hand gestures. In such interaction, the users move left and right to navigate the display, and they frequently adjust body proximity against the display thus to switch between overall views and focus views. These physical movements benefit information navigation, interaction modality switch, and user interface adaptation. But in more specific context of free hand selection in large displays, the effect of physical movements is less systematically investigated. To explore the potential of physical movements in free hand selection, a physical movements-adapted technique is developed and evaluated. The results show that the new technique has significant improvements in both selection efficiency and accuracy, the more difficult selection task the more obvious improvement in accuracy. Additionally, the new technique is preferred to the baseline of pointer acceleration (PA) technique by participants.
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| 12. |
- Qin, Changliang, et al.
(author)
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Process optimizations to recessed e-SiGe source/drain for performance enhancement in 22 nm all-last high-k/metal-gate pMOSFETs
- 2016
-
In: Solid-State Electronics. - : Elsevier. - 0038-1101 .- 1879-2405. ; 123, s. 38-43
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Journal article (peer-reviewed)abstract
- In this paper, the technology of recessed embedded SiGe (e-SiGe) source/drain (S/D) module is optimized for the performance enhancement in 22 nm all-last high-k/metal-gate (HK/MG) pMOSFETs. Different Si recess-etch techniques were applied in S/D regions to increase the strain in the channel and subsequently, improve the performance of transistors. A new recess-etch method consists of a two-step etch method is proposed. This process is an initial anisotropic etch for the formation of shallow trench followed by a final isotropic etch. By introducing the definition of the upper edge distance (D) between the recessed S/D region and the channel region, the process advantage of the new approach is clearly presented. It decreases the value of D than those by conventional one-step isotropic or anisotropic etch of Si. Therefore, the series resistance is reduced and the channel strain is increased, which confirmed by the simulation results. The physical reason of D reducing is analyzed in brief. Applying this recess design, the implant conditions for S/D extension (SDE) are also optimized by using a two-step implantation of BF2 in SiGe layers. The overlap space between doping junction and channel region has great effect on the device's performance. The designed implantation profile decreases the overlap space while keeps a shallow junction depth for a controllable short channel effect. The channel resistance as well as the transfer ID-VG curves varying with different process conditions are demonstrated. It shows the drive current of the device with the optimized SDE implant condition and Si recess-etch process is obviously improved. The change trend of on-off current distributions extracted from a series of devices confirmed the conclusions. This study provides a useful guideline for developing high performance strained PMOS SiGe technology.
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| 13. |
- Shen, Qian, et al.
(author)
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The Genome of Artemisia annua Provides Insight into the Evolution of Asteraceae Family and Artemisinin Biosynthesis
- 2018
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In: Molecular Plant. - : Cell Press. - 1674-2052 .- 1752-9867. ; 11:6, s. 776-788
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Journal article (peer-reviewed)abstract
- Artemisia annua, commonly known as sweet wormwood or Qinghao, is a shrub native to China and has long been used for medicinal purposes. A. annua is now cultivated globally as the only natural source of a potent anti-malarial compound, artemisinin. Here, we report a high-quality draft assembly of the 1.74-gigabase genome of A. annua, which is highly heterozygous, rich in repetitive sequences, and contains 63 226 protein-coding genes, one of the largest numbers among the sequenced plant species. We found that, as one of a few sequenced genomes in the Asteraceae, the A. annua genome contains a large number of genes specific to this large angiosperm clade. Notably, the expansion and functional diversification of genes encoding enzymes involved in terpene biosynthesis are consistent with the evolution of the artemisinin biosynthetic pathway. We further revealed by transcriptome profiling that A. annua has evolved the sophisticated transcriptional regulatory networks underlying artemisinin biosynthesis. Based on comprehensive genomic and transcriptomic analyses we generated transgenic A. annua lines producing high levels of artemisinin, which are now ready for large-scale production and thereby will help meet the challenge of increasing global demand of artemisinin.
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