| 1. |
- Fenstermacher, M.E., et al.
(författare)
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DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy
- 2022
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 62:4
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Tidskriftsartikel (refereegranskat)abstract
- DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance core and boundary plasmas. Substantial increases in off-axis current drive efficiency from an innovative top launch system for EC power, and in pressure broadening for Alfven eigenmode control from a co-/counter-I p steerable off-axis neutral beam, all improve the prospects for optimization of future long pulse/steady state high performance tokamak operation. Fundamental studies into the modes that drive the evolution of the pedestal pressure profile and electron vs ion heat flux validate predictive models of pedestal recovery after ELMs. Understanding the physics mechanisms of ELM control and density pumpout by 3D magnetic perturbation fields leads to confident predictions for ITER and future devices. Validated modeling of high-Z shattered pellet injection for disruption mitigation, runaway electron dissipation, and techniques for disruption prediction and avoidance including machine learning, give confidence in handling disruptivity for future devices. For the non-nuclear phase of ITER, two actuators are identified to lower the L-H threshold power in hydrogen plasmas. With this physics understanding and suite of capabilities, a high poloidal beta optimized-core scenario with an internal transport barrier that projects nearly to Q = 10 in ITER at ∼8 MA was coupled to a detached divertor, and a near super H-mode optimized-pedestal scenario with co-I p beam injection was coupled to a radiative divertor. The hybrid core scenario was achieved directly, without the need for anomalous current diffusion, using off-axis current drive actuators. Also, a controller to assess proximity to stability limits and regulate β N in the ITER baseline scenario, based on plasma response to probing 3D fields, was demonstrated. Finally, innovative tokamak operation using a negative triangularity shape showed many attractive features for future pilot plant operation.
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| 2. |
- Zheng, Y. H., et al.
(författare)
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Photocatalytic activity of Ag/ZnO heterostructure nanocatalyst: Correlation between structure and property
- 2008
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 112:29, s. 10773-10777
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Tidskriftsartikel (refereegranskat)abstract
- Ag/ZnO heterostructure nanocatalysts with Ag content of 1 wt % are successfully prepared through three different simple methods, where chemical reduction and photolysis reaction are adopted to fabricate the heterostructure. The dispersity of Ag clusters and/or nanoparticles in Ag/ZnO nanocatalyst is investigated by EDX mapping and XPS techniques. The experimental results show that deposition-precipitation is an efficient method to synthesize Ag/ZnO nanocatalyst with highly dispersed Ag clusters and/or nanoparticles; the photocatalytic activity of Ag/ZnO photocatalysts mainly depends on the dispersity of metallic Ag in Ag/ZnO nanocatalyst; the higher the dispersity of metallic Ag in Ag/ZnO nanocatalyst is, the higher the photocatalytic activity of Ag/ZnO photocatalyst should be. In addition, it is also found that the dispersity of Ag/ZnO photocatalyst in the dye solution is another key factor for liquid-phase photocatalysis due to the UV-light utilizing efficiency. The higher the UV-light utilizing efficiency is, the higher the photocatalytic activity of Ag/ZnO heterostructure photocatalyst should be.
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| 3. |
- Lin, XianQi, et al.
(författare)
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Metamaterial-inspired waveguide filters with compact size and sharp skirt selectivity
- 2013
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Ingår i: Journal Electromagnetic Waves and Applications. - : Informa UK Limited. - 0920-5071 .- 1569-3937. ; 27:2, s. 224-232
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a metamaterial-inspired miniaturization method for waveguide filter design is proposed. The transmission response and effective medium parameters of I-shaped resonator in metallic rectangular waveguide are first discussed. By embedding such an I-shaped resonator, a novel g/2-type inverter is then proposed ( g: the guided wavelength). The large effective refraction index with low loss which appears below the resonant frequency of the I-shaped resonator is skillfully exploited, and then the size of g/2-type inverter is greatly reduced with acceptable low insertion loss. The most negative permittivity of the I-shaped resonator at its resonant frequency produces an additional transmission zero which leads to sharp skirt selectivity in the upper side band. Using the novel g/2-type inverter, two improved waveguide filters are further designed with good performances. One has an extremely compact size. The other has further improved selectivity. Two such filters are finally fabricated and the measured results agree well with the simulated ones.
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| 4. |
- Wang, C. H., et al.
(författare)
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High-k dielectrics on (100) and (110) n-InAs: Physical and electrical characterizations
- 2014
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Ingår i: AIP Advances. - : AIP Publishing. - 2158-3226. ; 4:4
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Tidskriftsartikel (refereegranskat)abstract
- Two high-k dielectric materials (Al2O3 and HfO2) were deposited on n-type (100) and (110) InAs surface orientations to investigate physical properties of the oxide/semiconductor interfaces and the interface trap density (D-it). X-ray photoelectron spectroscopy analyses (XPS) for native oxides of (100) and (110) as-grown n-InAs epi wafers show an increase in As-oxide on the (100) surface and an increase in InOx on the (110) surface. In addition, XPS analyses of high-k (Al2O3 and HfO2) on n-InAs epi show that the intrinsic native oxide difference between (100) and (110) epi surfaces were eliminated by applying conventional in-situ pre-treatment (TriMethyAluminium (TMA)) before the high-k deposition. The capacitance-voltage (C-V) characterization of HfO2 and Al2O3 MOSCAPs on both types of n-InAs surfaces shows very similar C-V curves. The interface trap density (D-it) profiles show D-it minima of 6.1 x 10(12/)6.5 x 10(12) and 6.6 x 10(12)/7.3 x 10(12) cm(-2) eV(-1) for Al2O3 and HfO2, respectively for (100) and (110) InAs surfaces. The similar interface trap density (D-it) on (100) and (110) surface orientation were observed, which is beneficial to future InAs FinFET device with both (100) and (110) surface channel orientations present. (C) 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.
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| 5. |
- Wang, Z., et al.
(författare)
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A Sparse Model-Inspired Deep Thresholding Network for Exponential Signal Reconstruction--Application in Fast Biological Spectroscopy
- 2022
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Ingår i: IEEE Transactions on Neural Networks and Learning Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 2162-237X .- 2162-2388. ; 34:10, s. 7578-92
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Tidskriftsartikel (refereegranskat)abstract
- The nonuniform sampling (NUS) is a powerful approach to enable fast acquisition but requires sophisticated reconstruction algorithms. Faithful reconstruction from partially sampled exponentials is highly expected in general signal processing and many applications. Deep learning (DL) has shown astonishing potential in this field, but many existing problems, such as lack of robustness and explainability, greatly limit its applications. In this work, by combining the merits of the sparse model-based optimization method and data-driven DL, we propose a DL architecture for spectra reconstruction from undersampled data, called MoDern. It follows the iterative reconstruction in solving a sparse model to build the neural network, and we elaborately design a learnable soft-thresholding to adaptively eliminate the spectrum artifacts introduced by undersampling. Extensive results on both synthetic and biological data show that MoDern enables more robust, high-fidelity, and ultrafast reconstruction than the state-of-the-art methods. Remarkably, MoDern has a small number of network parameters and is trained on solely synthetic data while generalizing well to biological data in various scenarios. Furthermore, we extend it to an open-access and easy-to-use cloud computing platform (XCloud-MoDern), contributing a promising strategy for further development of biological applications.
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| 6. |
- Biollaz, S., et al.
(författare)
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Gas analysis in gasification of biomass and waste : Guideline report: Document 1
- 2018
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Rapport (refereegranskat)abstract
- Gasification is generally acknowledged as one of the technologies that will enable the large-scale production of biofuels and chemicals from biomass and waste. One of the main technical challenges associated to the deployment of biomass gasification as a commercial technology is the cleaning and upgrading of the product gas. The contaminants of product gas from biomass/waste gasification include dust, tars, alkali metals, BTX, sulphur-, nitrogen- and chlorine compounds, and heavy metals. Proper measurement of the components and contaminants of the product gas is essential for the monitoring of gasification-based plants (efficiency, product quality, by-products), as well as for the proper design of the downstream gas cleaning train (for example, scrubbers, sorbents, etc.). In practice, a trade-off between reliability, accuracy and cost has to be reached when selecting the proper analysis technique for a specific application. The deployment and implementation of inexpensive yet accurate gas analysis techniques to monitor the fate of gas contaminants might play an important role in the commercialization of biomass and waste gasification processes.This special report commissioned by the IEA Bioenergy Task 33 group compiles a representative part of the extensive work developed in the last years by relevant actors in the field of gas analysis applied to(biomass and waste) gasification. The approach of this report has been based on the creation of a team of contributing partners who have supplied material to the report. This networking approach has been complemented with a literature review. The report is composed of a set of 2 documents. Document 1(the present report) describes the available analysis techniques (both commercial and underdevelopment) for the measurement of different compounds of interest present in gasification gas. The objective is to help the reader to properly select the analysis technique most suitable to the target compounds and the intended application. Document 1 also describes some examples of application of gas analysis at commercial-, pilot- and research gasification plants, as well as examples of recent and current joint research activities in the field. The information contained in Document 1 is complemented with a book of factsheets on gas analysis techniques in Document 2, and a collection of video blogs which illustrate some of the analysis techniques described in Documents 1 and 2.This guideline report would like to become a platform for the reinforcement of the network of partners working on the development and application of gas analysis, thus fostering collaboration and exchange of knowledge. As such, this report should become a living document which incorporates in future coming progress and developments in the field.
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| 7. |
- Biollaz, S., et al.
(författare)
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Gas analysis in gasification of biomass and waste : Guideline report: Document 2 - Factsheets on gas analysis techniques
- 2018
-
Rapport (refereegranskat)abstract
- Gasification is generally acknowledged as one of the technologies that will enable the large-scale production of biofuels and chemicals from biomass and waste. One of the main technical challenges associated to the deployment of biomass gasification as a commercial technology is the cleaning and upgrading of the product gas. The contaminants of product gas from biomass/waste gasification include dust, tars, alkali metals, BTX, sulphur-, nitrogen- and chlorine compounds, and heavy metals. Proper measurement of the components and contaminants of the product gas is essential for the monitoring of gasification-based plants (efficiency, product quality, by-products), as well as for the proper design of the downstream gas cleaning train (for example, scrubbers, sorbents, etc.). The deployment and implementation of inexpensive yet accurate gas analysis techniques to monitor the fate of gas contaminants might play an important role in the commercialization of biomass and waste gasification processes.This special report commissioned by the IEA Bioenergy Task 33 group compiles a representative part of the extensive work developed in the last years by relevant actors in the field of gas analysis applied to (biomass and waste) gasification. The approach of this report has been based on the creation of a team of contributing partners who have supplied material to the report. This networking approach has been complemented with a literature review. This guideline report would like to become a platform for the reinforcement of the network of partners working on the development and application of gas analysis, thus fostering collaboration and exchange of knowledge. As such, this report should become a living document which incorporates in future coming progress and developments in the field.
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| 8. |
- Lin, H., et al.
(författare)
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Characteristics of electric vehicle charging demand at multiple types of location - Application of an agent-based trip chain model
- 2019
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Ingår i: Energy. - : Elsevier Ltd. - 0360-5442 .- 1873-6785. ; 188
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Tidskriftsartikel (refereegranskat)abstract
- This paper developed an agent-based trip chain model (ABTCM) to study the distribution of electric vehicles (EVs) charging demand and its dynamic characteristics, including flexibility and uncertainty, at different types of location. Key parameters affecting charging demand include charging strategies, i.e. uncontrolled charging (UC) and off-peak charging (OPC), and EV supply equipment, including three levels of charging equipment. The results indicate that the distributions of charging demand are similar as the travel patterns, featured by traffic flow at each location. A discrete peak effect was found in revealing the relation between traffic flow and charging demand, and it results in the smallest equivalent daily charging demand and peak load at public locations. EV charging and vehicle-to-grid (V2G) flexibility were examined by instantaneous adjustable power and accumulative adjustable amount of electricity. The EVs at home locations have the largest charging and V2G flexibility under the UC strategy, except for a period of regular working time. The V2G flexibility at work and public locations is generally larger than charging flexibility. Due to the fast charging application, the uncertainties of charging demand at public locations are the highest in all locations. In addition, the OPC strategy mitigates the uncertainty of charging demand.
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| 9. |
- Hsu, L. H., et al.
(författare)
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Design, Fabrication, and Reliability of Low-Cost Flip-Chip-On-Board Package for Commercial Applications up to 50 GHz
- 2012
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Ingår i: IEEE Transactions on Components, Packaging and Manufacturing Technology. - 2156-3985 .- 2156-3950. ; 2:3, s. 402-409
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a flip-chip-on-board (FCOB) packaging technology using a Rogers RO3210 laminate for microwave applications. Compared to the conventional microwave packaging architecture, the proposed FCOB technology skips one level of the ceramic package and thus results in lower reflections and manufacturing costs. To fulfill the small dimension requirement on printed circuit boards, the coplanar waveguide (CPW) transmission line and flip-chip bump were fabricated on a high-k RO3210 board (epsilon(r) = 10.2) with photolithography and electroplating. The GaAs chip patterned with the CPW line was then flip-chip-mounted onto the RO3210 laminate board. This structure displayed excellent performance from dc to 50 GHz with a return loss S-11 greater than 18 dB and insertion loss S-21 less than 0.5 dB. Meanwhile, the flip-chip bonding of the in-house-fabricated In0.52Al0.As-48/In0.6Ga0.4As metamorphic high-electron-mobility transistor devices on RO3210 also displayed excellent gain performance with a small degradation of 1 dB from dc to 40 GHz, showing the potential of implementing microwave integrated circuits on RO3210. To enhance the mechanical reliability, an epoxy-based underfill was injected into the flip-chip assemblies. Thermal cycling tests were performed to test the interconnect reliability, and the results indicated that the samples passed the thermal cycling test at least up to 600 cycles, showing excellent reliability for commercial applications. To the best of the authors' knowledge, this is the first study that evaluates the use of the RO3210 laminate for microwave flip-chip in open literature.
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| 10. |
- Jensen, D. Juul, et al.
(författare)
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Importance of local structural variations on recrystallization
- 2013
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Ingår i: Material Science Forum. - : Trans Tech Publications Inc.. - 9783037856888 ; , s. 37-41
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Konferensbidrag (refereegranskat)abstract
- Effects of local variations in the deformation microstructure on subsequent recrystallization are discussed and illustrated by three examples. The three examples consider local variations on different length scales and are: 1. Effects of local variations in the deformation microstructure on the formation of protrusions on migrating boundaries. 2. Effects of an inhomogeneous spatial distribution of second phase particles on growth. 3. Effects of stored energy and orientation variations on recrystallization kinetics.
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