| 1. |
- Liao, Wenlong, et al.
(författare)
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Scenario Generation for Cooling, Heating, and Power Loads Using Generative Moment Matching Networks
- 2022
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Ingår i: CSEE JOURNAL OF POWER AND ENERGY SYSTEMS. - : Power System Technology Press. - 2096-0042. ; 8:6, s. 1730-1740
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Tidskriftsartikel (refereegranskat)abstract
- Scenario generations of cooling, heating, and power loads are of great significance for the economic operation and stability analysis of integrated energy systems. In this paper, a novel deep generative network is proposed to model cooling, heating, and power load curves based on generative moment matching networks (GMMNs) where an auto-encoder transforms high-dimensional load curves into low-dimensional latent variables and the maximum mean discrepancy represents the similarity metrics between the generated samples and the real samples. After training the model, the new scenarios are generated by feeding Gaussian noises to the scenario generator of the GMMN. Unlike the explicit density models, the proposed GMMN does not need to artificially assume the probability distribution of the load curves, which leads to stronger universality. The simulation results show that the GMMN not only fits the probability distribution of multi-class load curves very well, but also accurately captures the shape (e.g., large peaks, fast ramps, and fluctuation), frequency-domain characteristics, and temporal-spatial correlations of cooling, heating, and power loads. Furthermore, the energy consumption of generated samples closely resembles that of real samples.
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| 2. |
- Liu, Peiji, et al.
(författare)
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A generalized method for the inherent energy performance modeling of machine tools
- 2021
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Ingår i: Journal of manufacturing systems. - : Elsevier BV. - 0278-6125 .- 1878-6642. ; 61, s. 406-422
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Tidskriftsartikel (refereegranskat)abstract
- Machine tools (MTs), as the key equipment of manufacturing systems, have enormous quantities and consume a great amount of energy. However, the diversity of both machines and their energy consumption properties make it difficult to transfer the energy-saving knowledge and services among different MT. To facilitate the initialization configuration of energy-saving services, the inherent energy performance (IEP) is investigated to describe the differences in energy consumption among MTs, and a generalized method for modeling the IEP of MT and its electrical subsystems is proposed. Three key enablers, including generalized experimental design rules, automatic coding, and data processing algorithms, are presented and integrated into a supporting system to reduce the modeling efforts and knowledge requirements. Case studies of an offline manufacturing scenario and an Internet of Things (IoT)-enabled manufacturing scenario were carried out to verify the effectiveness and convenience of the proposed method. The results show that the proposed method can provide essential modeling support for large-scale energy-saving service configurations and energy-efficient MT development.
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| 3. |
- Wang, Cao, et al.
(författare)
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Microstructure homogeneity control in spark plasma sintering of Al2O3 ceramics
- 2010
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Ingår i: Journal of the European Ceramic Society. - : Elsevier BV. - 0955-2219 .- 1873-619X. ; 31:1-2, s. 231-235
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Tidskriftsartikel (refereegranskat)abstract
- Homogeneous microstructure control in the SPS (spark plasma sintering) sintered big size Al2O3 ceramic was realized by the synergy effect of grain boundary tailoring and proper pressure profile design. Two-step pressure profile itself did not show any efficient densification enhancement if no grain boundary modifier MgO added. The two-step pressure profile can effectively reduce average grain size and grain size difference over the sintered specimen, while MgO doping can reduce the average grain size in the whole sintered samples. Finally, a general strategy to overcome the intrinsic temperature gradient in SPS is suggested.
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| 4. |
- Wang, Lichao, et al.
(författare)
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Hydrogen-treated mesoporous WO3 as a reducing agent of CO2 to fuels (CH4 and CH3OH) with enhanced photothermal catalytic performance
- 2016
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 4:14, s. 5314-5322
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Tidskriftsartikel (refereegranskat)abstract
- A series of mesoporous WO3 catalysts were facilely synthesized by a hydrothermal method using mesoporous silica KIT-6 as a hard template and silicotungstic acid as a precursor. All the catalysts possess a well-defined mesoporous structure with interconnected networks. Oxygen-deficient mesoporous WO3 (m-WO3-x) was prepared by hydrogenation treatment at different temperatures with improved photothermal coupling performance. Moreover, the as-prepared catalysts exhibit selectivity toward CH4 evolution under visible-light only irradiation. Then, under photothermal conditions, the results show that the concentration of oxygen vacancies of m-WO3 has a great influence on its catalytic performance. The CH4 evolution rate reached 25.77 mu mol g (1), which is about 22 times that of mesoporous WO3 (1.17 mu mol g(-1)) under the same conditions, and a moderate concentration of oxygen vacancies is necessary to achieve selectivity for the conversion of CO2 into CH4. A mechanism of the catalytic reduction of CO2 over m-WO3-x is proposed, in which the initial oxygen vacancies function as an excellent electron transfer mediator and decompose CO2 into its elements (C/CO). These findings may further broaden the scope for photothermal chemical conversion and provide new insights into the oxygen nonstoichiometry strategy for the development of CO2 reduction.
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| 5. |
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| 6. |
- Cao, C., et al.
(författare)
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Optimization of Curing Behavior of Si3N4 UV Resin for Photopolymerization 3D Printing
- 2019
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Ingår i: IOP Conference Series. - : Institute of Physics Publishing.
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Konferensbidrag (refereegranskat)abstract
- Silicon nitride (Si3N4) ceramics are widely used in mechanical and thermal management applications due to their excellent properties. To overcome the difficulties in traditional Si3N4 ceramic forming techniques, it is interesting to see the possibility of making complex-shaped silicon nitride ceramic component with novel 3D printing methods. In this study, we aim to study the effect of photo-initiators on the curing behavior of pre-formulated Si3N4 ceramic UV resin suspension. To elucidate the potential multi-factor interactions, a statistic experiment design was implemented in a sequence of screening and optimization by using Modde software. It was found that the kinds of photo-initiators, total amount of initiators and the mixture ratio between initiators have a great influence on the curing properties of silicon nitride UV ceramic resin. Based on these results, a formula was selected based on the criterion of using least amount photo-initiator while reaching the highest curing thickness.
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| 7. |
- Chen, Zhe, et al.
(författare)
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Toward FPGA Security in IoT : A New Detection Technique for Hardware Trojans
- 2019
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Ingår i: IEEE Internet of Things Journal. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2327-4662. ; 6:4, s. 7061-7068
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Tidskriftsartikel (refereegranskat)abstract
- Nowadays, field programmable gate array (FPGA) has been widely used in Internet of Things (IoT) since it can provide flexible and scalable solutions to various IoT requirements. Meanwhile, hardware Trojan (HT), which may lead to undesired chip function or leak sensitive information, has become a great challenge for FPGA security. Therefore, distinguishing the Trojan-infected FPGAs is quite crucial for reinforcing the security of IoT. To achieve this goal, we propose a clock-tree-concerned technique to detect the HTs on FPGA. First, we present an experimental framework which helps us to collect the electromagnetic (EM) radiation emitted by FPGA clock tree. Then, we propose a Trojan identifying approach which extracts the mathematical feature of obtained EM traces, i.e., 2-D principal component analysis (2DPCA) in this paper, and automatically isolates the Trojan-infected FPGAs from the Trojan-free ones by using a BP neural network. Finally, we perform extensive experiments to evaluate the effectiveness of our method. The results reveal that our approach is valid in detecting HTs on FPGA. Specifically, for the trust-hub benchmarks, we can find out the FPGA with always on Trojans (100% detection rate) while identifying the triggered Trojans with high probability (by up to 92%). In addition, we give a thorough discussion on how the experimental setup, such as probe step size, scanning area, and chip ambient temperature, affects the Trojan detection rate.
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| 8. |
- Cheng, Yajuan, et al.
(författare)
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Improvement and optimization of the growth quality of upright ZnOrod arrays by the response surface methodology
- 2015
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Ingår i: Applied Surface Science. - Amsterdam : Elsevier. - 0169-4332 .- 1873-5584. ; 351, s. 451-459
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Tidskriftsartikel (refereegranskat)abstract
- Response surface methodology was employed to guide the growth of ZnO rod arrays. With its assistance, the growth quality of the obtained samples was improved dramatically. The morphologies evolved from sparsely, randomly oriented rods to dense and upright rod arrays. Moreover, the significant parameters for ZnO rod arrays growth and their optimal regions were also determined. Furthermore, with the optimized parameters, the obtained aspect ratio of the vertically aligned ZnO rod arrays reached a value of 31. This is relatively a high value of ZnO rod arrays synthesized by wet chemical methods without capping agents in neutral solutions.
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| 9. |
- Cheng, Yajuan, et al.
(författare)
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Optimization of high-quality vertically aligned ZnO rod arrays by the response surface methodology
- 2015
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 626, s. 180-188
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Tidskriftsartikel (refereegranskat)abstract
- Optimization of the deposition parameters was conducted by the response surface methodology to synthesize high-quality ZnO rod arrays with a high texture coefficient, a large aspect ratio and a narrow bandgap. In addition, mathematical models based on statistical analysis were also developed to predict the texture coefficient, aspect ratio and bandgap of the ZnO rod arrays. With the optimized parameters, all of the three involved responses obtained the desired optimum values. The results show that the texture coefficient can be elevated up to a value of 0.998, which represents an almost perfect value. Moreover, wide range of aspect ratios was obtained for various applications and the obtained maximum value of 21.3 is relatively high value by wet chemical method, especially when no capping agent and no refreshing growth solution in a nearly neutral solution is used.
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| 10. |
- Dong, H., et al.
(författare)
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Effect of powder characteristics on the thermal conductivity and mechanical properties of Si 3 N 4 ceramics sintered by Spark plasma sintering
- 2019
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Ingår i: Journal of materials science. Materials in electronics. - : Springer-Verlag New York. - 0957-4522 .- 1573-482X. ; 30:8, s. 7590-7599
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Tidskriftsartikel (refereegranskat)abstract
- The effect of powder characteristics on the thermal conductivity and mechanical properties of silicon nitride (Si 3 N 4 ) ceramics were investigated systematically by using two α-Si 3 N 4 powders as raw materials and using MgSiN 2 or MgO + Y 2 O 3 as sintering additives. The Si 3 N 4 ceramics with a higher density were obtained by α-Si 3 N 4 powders with lower oxygen content and impurities and using none-oxide sintering additive MgSiN 2 . The α–β phase transformation completely taken place in all the specimen at 1750 °C. The specimens sintered by powders with lower levels of oxygen and impurities show higher mechanical properties than other specimens. The Y 2 O 3 and MgO sintering additives lead to higher flexural strength and fracture toughness than MgSiN 2 . The Vickers’ hardness is just the opposite. The thermal conductivity value of powders with lower oxygen content is higher than that of the materials prepared by the other type of powder at the same conditions. The effects of the Si 3 N 4 particle size, native oxygen and impurities on the thermal conductivity of resultant materials were discussed in detail. This work demonstrates that the improvement in thermal conductivity of Si 3 N 4 can be obtained by using none-oxide sintering additive MgSiN 2 and the Si 3 N 4 powder with lower oxygen content, and impurities.
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