| 1. |
- Li, J. W., et al.
(author)
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Magnetocaloric effect in heavy rare-earth elements doped Fe-based bulk metallic glasses with tunable Curie temperature
- 2014
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In: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 116:6, s. Art. no. 063902-
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Journal article (peer-reviewed)abstract
- The effects of heavy rare earth (RE) additions on the Curie temperature (T-C) and magnetocaloric effect of the Fe-RE-B-Nb (RE-Gd, Dy and Ho) bulk metallic glasses were studied. The type of dopping RE element and its concentration can easily tune T-C in a large temperature range of 120K without significantly decreasing the magnetic entropy change (Delta S-M) and refrigerant capacity (RC) of the alloys. The observed values of Delta S-M and RC of these alloys compare favorably with those of recently reported Fe-based metallic glasses with enhanced RC compared to Gd5Ge1.9Si2Fe0.1. The tunable T-C and large glass-forming ability of these RE doped Fe-based bulk metallic glasses can be used in a wide temperature range with the final required shapes.
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| 2. |
- Zhang, Yaoxin, et al.
(author)
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Could social robots facilitate children with autism spectrum disorders in learning distrust and deception?
- 2019
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In: Computers in Human Behavior. - : Elsevier BV. - 0747-5632. ; 98, s. 140-149
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Journal article (peer-reviewed)abstract
- Social robots have been increasingly involved in our daily lives and provide a new environment for children's growth. The current study aimed to examine how children with and without Autism Spectrum Disorders (ASD)learned complex social rules from a social robot through distrust and deception games. Twenty children with ASD between the ages of 5–8 and 20 typically-developing (TD)peers whose age and IQ were matched participated in distrust and deception tasks along with an interview about their perception of the human-likeness of the robot. The results demonstrated that: 1)children with ASD were slower to learn to and less likely to distrust and deceive a social robot than TD children and 2)children with ASD who perceived the robot to appear more human-like had more difficulty in learning to distrust the robot. Besides, by comparing to a previous study the results showed that children with ASD appeared to have more difficulty in learning to distrust a human compared to a robot, particularly in the early phase of learning. Overall, our study verified that social robots could facilitate children with ASD's learning of some social rules and showed that children's perception of the robot plays an important role in their social learning, which provides insights on robot design and its clinical applications in ASD intervention.
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| 3. |
- Zhao, Jie, et al.
(author)
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Microstructure-tunable highly conductive graphene-metal composites achieved by inkjet printing and low temperature annealing
- 2018
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In: Journal of Micromechanics and Microengineering. - : IOP PUBLISHING LTD. - 0960-1317 .- 1361-6439. ; 28:3
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Journal article (peer-reviewed)abstract
- We present a method for fabricating highly conductive graphene-silver composite films with a tunable microstructure achieved by means of an inkjet printing process and low temperature annealing. This is implemented by starting from an aqueous ink formulation using a reactive silver solution mixed with graphene nanoplatelets (GNPs), followed by inkjet printing deposition and annealing at 100 degrees C for silver formation. Due to the hydrophilic surfaces and the aid of a polymer stabilizer in an aqueous solution, the GNPs are uniformly covered with a silver layer. Simply by adjusting the content of GNPs in the inks, highly conductive GNP/Ag composites (> 106 S m(-1)), with their microstructure changed from a large-area porous network to a compact film, is formed. In addition, the printed composite films show superior quality on a variety of unconventional substrates compared to its counterpart without GNPs. The availability of composite films paves the way to the metallization in different printed devices, e.g. interconnects in printed circuits and electrodes in energy storage devices.
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| 4. |
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| 5. |
- Majee, Subimal, 1984-, et al.
(author)
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Production of transparent and conductive stable graphene ink for inkjet printing method
- 2015
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Conference paper (peer-reviewed)abstract
- Electrical interconnections are one of the main challenges in the printed electronics, to connect different functional units of an electronic device. With the progressive advancement of large area and low cost printed electronic devices on polymeric and paper substrates, the requirement for reliable interconnections with lower power consumption fabricated at low temperature is necessary. The conventional copper-based interconnections suffer severe problems in terms of cost efficiency when they are processed with photolithography technique. To replace the conventional metallic interconnections we have proposed printed interconnects with graphene inks. This is mainly motivated by two reasons. First, printing is a low-cost patterning approach which is performed at ordinary ambient condition. Printing of graphene proved to be a promising since it combines the attractive features of graphene and the cost effective printing methods (ink-jet printing, nozzle printing, spray printing) which enable additive patterning, direct writing, scalability to large area manufacturing. In order to facilitate the inkjet printing process, the graphene solution needs to be highly stable, uniform and should contain smaller sheet sizes (~ 1 micro meter) because of the limitation of the nozzle size of inkjet printing machine. In this work we have proposed a cost-effective approach for large-scale production of printable stable graphene suspension by liquid-phase shear exfoliation of graphite for printed electronics application. The process is scalable and requires shorter processing time compared to the other existing exfoliation methods. Graphene sheets have been exfoliated from graphite flakes in a solvent, cyclohexanone with ethyl cellulose as stabilizer. The graphene based solution prepared after several optimizations leads to a stable ink for more than six months without any sedimentation. The initial studies confirmed the production of graphene films with average sheet thickness of 10 to 20 nm and without any agglomeration with sheet sizes less than 1 micro meter. The rheological properties, such as, viscosity, of the produced graphene ink has been carefully tuned in order for successful inkjet printing process. Highly conductive and transparent (~70 % in the visible region) interconnections have been developed after several inkjet printing steps.
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| 6. |
- Man, Weizhen, et al.
(author)
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Synthesis of novel CuO@Graphene nanocomposites for lubrication application via a convenient and economical method
- 2022
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In: Wear. - : Elsevier. - 0043-1648 .- 1873-2577. ; 498-499
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Journal article (peer-reviewed)abstract
- Graphene-based nano lubricant additives attract more and more attention because of their superior lubricating performance as well as green and ashless properties. Graphene-based nanocomposites exhibit excellent tribological performances due to the synergistic “slide-roll” effect. In this work, we developed a novel nanocomposite constructed by graphene materials (G) and CuO nanoparticles, named CuO@G, which has superior tribological properties to each component (pure CuO or pure graphene materials) and the mixture (Graphene + CuO) under different testing conditions due to the synergistic effect. By adding 0.5 wt% CuO@G to PAO-6 oil, the coefficient of friction (COF) is reduced by more than 50%, and the wear scar almost disappears. The study provides a novel and promising method for the synthesis of graphene-based lubrication nanomaterials, which has high potential for lubrication applications.
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| 7. |
- Mitola, Joseph, et al.
(author)
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Accelerating 5G QoE via public-private spectrum sharing
- 2014
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In: IEEE Communications Magazine. - : Institute of Electrical and Electronics Engineers Inc.. - 0163-6804 .- 1558-1896. ; 52:5, s. 77-85
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Journal article (peer-reviewed)abstract
- Fifth generation wireless systems (5G) must achieve high user Quality of Experience (QoE) in order to compete for market share. Each candidate 5G wireless radio frequency (RF) band offers advantages such as longer range or higher data rate than 2G, 3G, and 4G, but no single band or air interface standard by itself fully achieves ubiquitous levels of QoE for the complete range of wireless access devices. Spectrum clearing cannot keep pace with user demand, so public-private spectrum sharing is emerging as an affordable, near-term method of increasing radio access network (RAN) capacities for content delivery. This paper presents a fresh look at QoE; spectrum scarcity; public uses that underutilize candidate 5G radio frequency (RF) spectrum; and emerging public-private radio interference management frameworks that enable near-term spectrum sharing, with positive consequences for 5G price, performance, and total user QoE.
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| 8. |
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| 9. |
- Wang, Yaqiong, et al.
(author)
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Domain Wall Free Polar Structure Enhanced Photodegradation Activity in Nanoscale Ferroelectric BaxSr1-xTiO3
- 2020
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In: Advanced Energy Materials. - : WILEY-V C H VERLAG GMBH. - 1614-6832 .- 1614-6840. ; 10:38
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Journal article (peer-reviewed)abstract
- Ferroelectric materials exhibit anomalous behavior due to the presence of domains and domain walls which are related to the spontaneous polarization inherent in the crystal structure. Control of ferroelectric domains and domain walls has been used to enhance device performances in ultrasound, pyroelectric detectors, and photovoltaic systems with renewed interest in nanostructuring for energy applications. It is also known that ferroelectrics including domain walls can double photocatalytic rate and increase carrier lifetime from microsecond to millisecond. However, there remains a lack of understanding on the different contributions of the domain and domain walls to photocatalytic activities. Herein it is found, by comparing samples of nanostructured Ba(x)Sr(1-)(x)TiO(3)with and without a polar domain, that the material with polar domains has a faster reaction rate (k= 0.18 min(-1)) than the nonpolar one (k= 0.11 min(-1)). It is further revealed that the observed enhanced photoactivity of perovskite ferroelectric materials stems from the inherent polarization of the domain instead of domain walls. Here, the new understanding of the underlying physics of materials with a spontaneous dipole opens a door to enhance the performance of light induced energy harvesting systems.
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| 10. |
- Zhang, Man, et al.
(author)
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Analysis of SiC MOSFETs Short-Circuit behavior in Half Bridge Configuration during Shoot-Through Event
- 2023
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In: 2023 IEEE Energy Conversion Congress and Exposition, ECCE 2023. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 5350-5358
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Conference paper (peer-reviewed)abstract
- This paper investigates the short-circuit behavior of SiC MOSFETs in half bridge configuration during shoot-through event. The short-circuit peak current (ISCP) as well as the distribution of drain to source voltage (VDS) of half bridge configuration are analyzed under various mismatch operating condition. Further, the determinants on total amount and distribution of short-circuit energy (SC energy) are obtained. It is revealed that the device with the lowest short-circuit current carrying capacity determines the ISCP and the total SC energy of half bridge leg. Besides, the decrease of active switch common source inductance can mitigate the VDS and SC energy imbalance caused by load current. The conclusions are validated by experimental results.
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