| 1. |
- Chen, Haiyang, et al.
(författare)
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A guest-assisted molecular-organization approach for >17% efficiency organic solar cells using environmentally friendly solvents
- 2021
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Ingår i: Nature Energy. - : NATURE PORTFOLIO. - 2058-7546. ; 6:11, s. 1045-1053
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Tidskriftsartikel (refereegranskat)abstract
- The power conversion efficiencies (PCEs) of laboratory-sized organic solar cells (OSCs), usually processed from low-boiling-point and toxic solvents, have reached high values of over 18%. However, there is usually a notable drop of the PCEs when green solvents are used, limiting practical development of OSCs. Herein, we obtain certificated PCEs over 17% in OSCs processed from a green solvent paraxylene (PX) by a guest-assisted assembly strategy, where a third component (guest) is employed to manipulate the molecular interaction of the binary blend. In addition, the high-boiling-point green solvent PX also enables us to deposit a uniform large-area module (36 cm(2)) with a high efficiency of over 14%. The strong molecular interaction between the host and guest molecules also enhances the operational stability of the devices. Our guest-assisted assembly strategy provides a unique approach to develop large-area and high-efficiency OSCs processed from green solvents, paving the way for industrial development of OSCs. Organic solar cells processed from green solvents are easier to implement in manufacturing yet their efficiency is low. Chen et al. devise a guest molecule to improve the molecular packing, enabling devices with over 17% efficiency.
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| 2. |
- Fan, Qunping, 1989, et al.
(författare)
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Mechanically Robust All-Polymer Solar Cells from Narrow Band Gap Acceptors with Hetero-Bridging Atoms
- 2020
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Ingår i: Joule. - : Elsevier BV. - 2542-4351. ; 4:3, s. 658-672
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Tidskriftsartikel (refereegranskat)abstract
- We developed three narrow band-gap polymer acceptors PF2-DTC, PF2-DTSi, and PF2-DTGe with different bridging atoms (i.e., C, Si, and Ge). Studies found that such different bridging atoms significantly affect the crystallinity, extinction coefficient, electron mobility of the polymer acceptors, and the morphology and mechanical robustness of related active layers. In all-polymer solar cells (all-PSCs), these polymer acceptors achieved high power conversion efficiencies (PCEs) over 8.0%, while PF2-DTSi obtained the highest PCE of 10.77% due to its improved exciton dissociation, charge transport, and optimized morphology. Moreover, the PF2-DTSi-based active layer showed excellent mechanical robustness with a high toughness value of 9.3 MJ m−3 and a large elongation at a break of 8.6%, which is a great advantage for the practical applications of flexible devices. As a result, the PF2-DTSi-based flexible all-PSC retained >90% of its initial PCE (6.37%) after bending and relaxing 1,200 times at a bending radius of ∼4 mm.
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| 3. |
- Radamson, Henry H., et al.
(författare)
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State of the Art and Future Perspectives in Advanced CMOS Technology
- 2020
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Ingår i: Nanomaterials. - : MDPI AG. - 2079-4991. ; 10:8
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Forskningsöversikt (refereegranskat)abstract
- The international technology roadmap of semiconductors (ITRS) is approaching the historical end point and we observe that the semiconductor industry is driving complementary metal oxide semiconductor (CMOS) further towards unknown zones. Today's transistors with 3D structure and integrated advanced strain engineering differ radically from the original planar 2D ones due to the scaling down of the gate and source/drain regions according to Moore's law. This article presents a review of new architectures, simulation methods, and process technology for nano-scale transistors on the approach to the end of ITRS technology. The discussions cover innovative methods, challenges and difficulties in device processing, as well as new metrology techniques that may appear in the near future.
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| 4. |
- Zhou, Yueting, et al.
(författare)
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Self-calibrated NICE-OHMS based on an asymmetric signal : theoretical analysis and experimental validation
- 2023
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087. ; 31:17, s. 27830-27842
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Tidskriftsartikel (refereegranskat)abstract
- As an ultra-sensitive detection technique, the noise-immune cavity enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) technique has great potential for assessment of the concentration of trace gases. To determine gas concentrations at the ppt or lower level with high accuracy, it is desirable that the technique exhibits self-calibration (or calibration-free) capabilities. Although being sensitive, NICE-OHMS has so far not demonstrated any such ability. To remedy this, this paper provides a self-calibrated realization of NICE-OHMS that is based on a switching of the feedback target of the DeVoe-Brewer (DVB) locking procedure from the modulation frequency of the frequency modulation spectroscopy (FMS) to the cavity length, which creates an asymmetrical signal whose form and size can be used to unambiguously assess the gas concentration. A comprehensive theoretical model for self-calibrated NICE-OHMS is established by analyzing the shift of cavity modes caused by intracavity absorption, demonstrating that gas absorption information can be encoded in both the laser frequency and the NICE-OHMS signal. To experimentally verify the methodology, we measure a series of dispersion signals under different levels of absorbance using a built experimental setup. An instrument factor and the partial pressure are obtained by fitting the measured signal through theoretical expressions. Our results demonstrate that fitted values are more accurate for higher partial pressures than for lower. To improve on the accuracy at low partial pressures, it is shown that the instrument factor obtained by fitting the signal at large partial pressures (in this case, above 7.8 µTorr) can be set to a fixed value for all fits. By this, the partial pressures can be assessed with a relative error below 0.65%. This technique has the potential to enable calibration-free ultra-sensitive gas detection.
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| 5. |
- Jiang, Pei, et al.
(författare)
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Energy consumption prediction and optimization of industrial robots based on LSTM
- 2023
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Ingår i: Journal of manufacturing systems. - : Elsevier BV. - 0278-6125 .- 1878-6642. ; 70, s. 137-148
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Tidskriftsartikel (refereegranskat)abstract
- Due to wide distribution and low energy efficiency, the energy-saving of industrial robots draws more and more attention, and a large number of methods have emerged to predict or optimize the energy consumption (EC) of robots. However, many dynamic and electrical parameters are unavailable due to the commercial limitations of industrial robots, which constrains the application of those model-based methods. Therefore, this paper proposes a data-driven method for the prediction and optimization of robot EC. Initially, the cause-and-effect relationship between robot EC and joint motion variables, such as the joint position, velocity, and acceleration, is qualitatively analyzed based on the influence of the capacitive and inductive components in the drive system. And a deep neural network based on long short-term memory (LSTM) is proposed to reveal the nonlinear mapping between the industrial robot EC and the joint motion variables, which can predict EC without the parameters of the industrial robot. Based on the proposed neural network, the adaptive genetic algorithm is adopted to optimize the time-variant scaling function, which can optimize the scaled trajectory to reduce EC without hardware modification. To validate the accuracy and efficacy of the proposed method, experiments are conducted on a KUKA KR60-3 six degree-of-freedom (DOF) industrial robot. The results demonstrate that the proposed neural network can predict EC with a mean absolute percentage error less than 4.21% and the proposed method reduces the EC by 22.35%.
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| 6. |
- Li, Xiaobin, et al.
(författare)
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Knowledge graph based OPC UA information model automatic construction method for heterogeneous devices integration
- 2024
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Ingår i: Robotics and Computer-Integrated Manufacturing. - : Elsevier BV. - 0736-5845 .- 1879-2537. ; 88
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Tidskriftsartikel (refereegranskat)abstract
- Emergent manufacturing paradigms, including ubiquitous manufacturing, social manufacturing, and agile manufacturing, facilitate the advancement of the manufacturing industry. However, these paradigms suffer from the difficulty of interoperability due to the heterogeneity of field devices and diverse communication protocols. The OLE for Process Control Unified Architecture (OPC UA) technique, which is featured with cross-platform, is considered as the pivotal technology for addressing this issue. However, there still exist a large number of heterogeneous devices which do not support OPC UA protocol. The communication protocols of these heterogeneous devices need to be converted into OPC UA based on information model, nevertheless, the manual construction of OPC UA information model is cumbersome and inefficient. In this paper, an integrated architecture based on reasoning over the OPC UA information model is proposed to realize rapid integration of heterogeneous devices to achieve interoperability. To realize the proposed integrated architecture, an automatic device information model construction method is developed simultaneously. The method first identifies the type of the newly accessed device based on the character-level TextCNN (CTCNN) model, which utilizes the word sequence extracted from the corresponding device data frame as input. Subsequently an open-world knowledge completion model is adopted to link the unseen entities in the device data frame to the information model knowledge graph(KG) to support the information model automatic construction for unknown device. For evaluation purpose, two industrial datasets are constructed and the results demonstrate the feasibility and effectiveness of the proposed method.
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| 7. |
- 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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| 8. |
- Liu, Yangyang, et al.
(författare)
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Promoted rate and cycling capability of Li–S batteries enabled by targeted selection of co-solvent for the electrolyte
- 2020
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Ingår i: Energy Storage Materials. - : Elsevier BV. - 2405-8297. ; 25, s. 131-136
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Tidskriftsartikel (refereegranskat)abstract
- Lithium sulfur (Li–S) batteries are considered as promising candidates for high-energy-density battery systems owing to the high theoretical capacity of sulfur (1675 mAh g−1) and low cost of raw materials. However, their practical application is hampered by low rate capability and rapid degradation of capacity, arising from the passivation of the cathode by lithium sulfides (Li2S2/Li2S) deposited during discharge and low interfacial stability of the Li anode. Herein, we report on a comprehensive strategy to select co-solvent to the electrolyte to regulate the deposition of lithium sulfides during charge-discharge process. We show that addition of a co-solvent with high solubility, and strong interaction with Li2S to a conventional electrolyte effectively mitigates the formation of a passivating layer on the sulfur cathode and dramatically improves the interfacial stability of the Li anode. We demonstrate that Sulfolane (SL) has these properties and that a Li–S cell with an electrolyte containing 6 vol% SL exhibits outstanding cyclic performance (0.083% decay per cycle) and rate capability (capacity density of 765 mAh g−1 at rate of 1.0C). Thus, we provide a facile strategy for the selection of co-solvent for improved performance of Li–S batteries, realizing their practical application for high-energy-density battery systems.
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| 9. |
- Pi, Xuehui, et al.
(författare)
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Mapping global lake dynamics reveals the emerging roles of small lakes
- 2022
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Lakes are important natural resources and carbon gas emitters and are undergoing rapid changes worldwide in response to climate change and human activities. A detailed global characterization of lakes and their long-term dynamics does not exist, which is however crucial for evaluating the associated impacts on water availability and carbon emissions. Here, we map 3.4 million lakes on a global scale, including their explicit maximum extents and probability-weighted area changes over the past four decades. From the beginning period (1984–1999) to the end (2010–2019), the lake area increased across all six continents analyzed, with a net change of +46,278 km2, and 56% of the expansion was attributed to reservoirs. Interestingly, although small lakes (<1 km2) accounted for just 15% of the global lake area, they dominated the variability in total lake size in half of the global inland lake regions. The identified lake area increase over time led to higher lacustrine carbon emissions, mostly attributed to small lakes. Our findings illustrate the emerging roles of small lakes in regulating not only local inland water variability, but also the global trends of surface water extent and carbon emissions.
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| 10. |
- Radamson, Henry H., et al.
(författare)
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Miniaturization of CMOS
- 2019
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Ingår i: Micromachines. - : MDPI AG. - 2072-666X. ; 10:5
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Tidskriftsartikel (refereegranskat)abstract
- When the international technology roadmap of semiconductors (ITRS) started almost five decades ago, the metal oxide effect transistor (MOSFET) as units in integrated circuits (IC) continuously miniaturized. The transistor structure has radically changed from its original planar 2D architecture to today's 3D Fin field-effect transistors (FinFETs) along with new designs for gate and source/drain regions and applying strain engineering. This article presents how the MOSFET structure and process have been changed (or modified) to follow the More Moore strategy. A focus has been on methodologies, challenges, and difficulties when ITRS approaches the end. The discussions extend to new channel materials beyond the Moore era.
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