| 1. |
- Birney, Ewan, et al.
(författare)
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Identification and analysis of functional elements in 1% of the human genome by the ENCODE pilot project
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 447:7146, s. 799-816
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Tidskriftsartikel (refereegranskat)abstract
- We report the generation and analysis of functional data from multiple, diverse experiments performed on a targeted 1% of the human genome as part of the pilot phase of the ENCODE Project. These data have been further integrated and augmented by a number of evolutionary and computational analyses. Together, our results advance the collective knowledge about human genome function in several major areas. First, our studies provide convincing evidence that the genome is pervasively transcribed, such that the majority of its bases can be found in primary transcripts, including non-protein-coding transcripts, and those that extensively overlap one another. Second, systematic examination of transcriptional regulation has yielded new understanding about transcription start sites, including their relationship to specific regulatory sequences and features of chromatin accessibility and histone modification. Third, a more sophisticated view of chromatin structure has emerged, including its inter-relationship with DNA replication and transcriptional regulation. Finally, integration of these new sources of information, in particular with respect to mammalian evolution based on inter- and intra-species sequence comparisons, has yielded new mechanistic and evolutionary insights concerning the functional landscape of the human genome. Together, these studies are defining a path for pursuit of a more comprehensive characterization of human genome function.
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| 2. |
- Chen, Yicheng, et al.
(författare)
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Computational fluid-structure interaction analysis of flapping uvula on aerodynamics and pharyngeal vibration in a pediatric airway
- 2023
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 13:1, s. 2013-
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Tidskriftsartikel (refereegranskat)abstract
- The uvula flapping is one of the most distinctive features of snoring and is critical in affecting airway aerodynamics and vibrations. This study aimed to elucidate the mechanism of pharyngeal vibration and pressure fluctuation due to uvula flapping employing fluid-structure interaction simulations. The followings are the methodology part: we constructed an anatomically accurate pediatric pharynx model and put attention on the oropharynx region where the greatest level of upper airway compliance was reported to occur. The uvula was assumed to be a rigid body with specific flapping frequencies to guarantee proper boundary conditions with as little complexity as possible. The airway tissue was considered to have a uniform thickness. It was found that the flapping frequency had a more significant effect on the airway vibration than the flapping amplitude, as the flapping uvula influenced the pharyngeal aerodynamics by altering the jet flow from the mouth. Breathing only through the mouth could amplify the effect of flapping uvula on aerodynamic changes and result in more significant oropharynx vibration.
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| 3. |
- Chen, Yicheng, et al.
(författare)
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Evaluation of computational fluid dynamics models for predicting pediatric upper airway airflow characteristics
- 2023
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Ingår i: Medical and Biological Engineering and Computing. - : Springer. - 0140-0118 .- 1741-0444. ; 61:1, s. 259-270
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Tidskriftsartikel (refereegranskat)abstract
- Computational fluid dynamics (CFD) has the potential for use as a clinical tool to predict the aerodynamics and respiratory function in the upper airway (UA) of children; however, careful selection of validated computational models is necessary. This study constructed a 3D model of the pediatric UA based on cone beam computed tomography (CBCT) imaging. The pediatric UA was 3D printed for pressure and velocity experiments, which were used as reference standards to validate the CFD simulation models. Static wall pressure and velocity distribution inside of the UA under inhale airflow rates from 0 to 266.67 mL/s were studied by CFD simulations based on the large eddy simulation (LES) model and four Reynolds-averaged Navier-Stokes (RANS) models. Our results showed that the LES performed best for pressure prediction; however, it was much more time-consuming than the four RANS models. Among the RANS models, the Low Reynolds number (LRN) SST k-ω model had the best overall performance at a series of airflow rates. Central flow velocity determined by particle image velocimetry was 3.617 m/s, while velocities predicted by the LES, LRN SST k-ω, and k-ω models were 3.681, 3.532, and 3.439 m/s, respectively. All models predicted jet flow in the oropharynx. These results suggest that the above CFD models have acceptable accuracy for predicting pediatric UA aerodynamics and that the LRN SST k-ω model has the most potential for clinical application in pediatric respiratory studies.
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| 4. |
- Chen, Yicheng, et al.
(författare)
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Impact of sleep posture and breathing pattern on soft palate flutter and pharynx vibration in a pediatric airway using fluid-structure interaction
- 2023
-
Ingår i: Journal of Biomechanics. - : Elsevier. - 0021-9290 .- 1873-2380. ; 152
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Tidskriftsartikel (refereegranskat)abstract
- Snoring is a common condition in the general population, and the management of snoring requires a better understanding of its mechanism through a fluid-structure interaction (FSI) perspective. Despite the recent popularity of numerical FSI techniques, outstanding challenges are accurately predicting airway deformation and its vibration during snoring due to complex airway morphology. In addition, there still needs to be more un-derstanding of snoring inhibition when lying on the side, and the possible effect of airflow rates, as well as nose or mouth-nose breathing, on snoring remains to be investigated. In this study, an FSI method verified against in vitro models was introduced to predict upper airway deformation and vibration. The technique was applied to predict airway aerodynamics, soft palate flutter, and airway vibration in four sleep postures (supine, left/right lying, and sitting positions) and four breathing patterns (mouth-nose, nose, mouth, and unilateral nose breathing). It was found that, at given elastic properties of soft tissues, the evaluated flutter frequency of 19.8 Hz in inspiration was in good agreement with the reported frequency of snoring sound in literature. Reduction in flutter and vibrations due to the mouth-nose airflow proportion changes were also noticed when having side-lying and sitting positions. Breathing through the mouth results in larger airway deformation than breathing through the nose or mouth-nose. These results collectively demonstrate the potential of FSI for studying the physics of airway vibration and clarify to some degree the reason for snoring inhibition during sleep postures and breathing patterns.
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| 5. |
- Hudson, Thomas J., et al.
(författare)
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International network of cancer genome projects
- 2010
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 464:7291, s. 993-998
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Tidskriftsartikel (refereegranskat)abstract
- The International Cancer Genome Consortium (ICGC) was launched to coordinate large-scale cancer genome studies in tumours from 50 different cancer types and/or subtypes that are of clinical and societal importance across the globe. Systematic studies of more than 25,000 cancer genomes at the genomic, epigenomic and transcriptomic levels will reveal the repertoire of oncogenic mutations, uncover traces of the mutagenic influences, define clinically relevant subtypes for prognosis and therapeutic management, and enable the development of new cancer therapies.
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| 6. |
- Kozhevnikov, Evgeny, et al.
(författare)
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A dual-transduction-integrated biosensing system to examine the 3D cell-culture for bone regeneration
- 2019
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Ingår i: Biosensors & bioelectronics. - : ELSEVIER ADVANCED TECHNOLOGY. - 0956-5663 .- 1873-4235. ; 141
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Tidskriftsartikel (refereegranskat)abstract
- Three-dimensional (3D) cell cultures developed with living cells and scaffolds have demonstrated outstanding potential for tissue engineering and regenerative medicine applications. However, no suitable tools are available to monitor dynamically variable cell behavior in such a complex microenvironment. In particular, simultaneously assessing cell behavior, cell secretion, and the general state of a 3D culture system is of a really challenging task. This paper presents our development of a dual-transduction-integrated biosensing system that assesses electrical impedance in conjunction with imaging techniques to simultaneously investigate the 3D cell-culture for bone regeneration. First, we created models to mimic the dynamic deposition of the extracellular matrix (ECM) in 3D culture, which underwent osteogenesis by incorporating different amounts of bone-ECM components (collagen, hydroxyapatite [HAp], and hyaluronic acid [HA]) into alginate-based hydrogels. The formed models were investigated by means of electrical impedance spectroscopy (EIS), with the results showing that the impedances increased linearly with collagen and hyaluronan, but changed in a more complex manner with HAp. Thereafter, we created two models that consisted of primary osteoblast cells (OBs), which expressed the enhanced green fluorescent protein (EGFP), and 4T1 cells, which secreted the EGFP-HA, in the alginate hydrogel. We found the capacitance (associated with impedance and measured by EIS) increased with the increases in initial embedded OBs, and also confirmed the cell proliferation over 3 days with the EGFP signal as monitored by the fluorescent imaging component in our system. Interestingly, the change in capacitance is found to be associated with OB migration following stimulation. Also, we show higher capacitance in 4T1 cells that secret HA when compared to control 4T1 cells after a 3-day culture. Taken together, we demonstrate that our biosensing system is able to investigate the dynamic process of 3D culture in a non-invasive and real-time manner.
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| 7. |
- Li, Ruiyun, et al.
(författare)
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Operando Formation of Van der Waals Heterostructures for Achieving Macroscale Superlubricity on Engineering Rough and Worn Surfaces
- 2022
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Ingår i: Advanced Functional Materials. - : John Wiley & Sons. - 1616-301X .- 1616-3028. ; 32:18
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Tidskriftsartikel (refereegranskat)abstract
- Macroscale superlubricity breakdown of lubricating materials caused by substrate surface roughening and mechanochemical modification poses great challenges for their practical tribological applications. Here, a facile way is reported to access robust macroscale superlubricity in a vacuum environment, via the operando formation of graphene/transition-metal dichalcogenide (TMDC) heterostructures at wear-induced rough surfaces. By trapping active amorphous carbon (a-C) wear products between TMDC flakes, the sandwich structures readily transform into graphene/TMDC heterostructures during running-in stage, based on shear-induced confinement and load-driven graphitization effects. Then they assemble into multipoint flake-like tribofilms to achieve macroscale superlubricity at steady stage by reducing contact area, eliminating strong cross-interface carbon–carbon interactions and polishing a-C rough nascent surface. Atomistic simulations reveal the preferential formation of graphene/TMDC heterostructures during running-in stage and demonstrate the superlubric sliding of TMDCs on the graphene. The findings are of importance to achieve robust superlubricity and provide a good strategy for the synthesis of other van der Waals heterostructures.
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| 8. |
- Liang, Xiubo, et al.
(författare)
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Menstrual Monster : A Tangible Interactive Co-educational Game Designed for Teenagers
- 2022
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Ingår i: CHI EA '22. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450391566
-
Konferensbidrag (refereegranskat)abstract
- Learning menstruation in early adolescence could reduce teenagers’ misunderstanding of it and help them treat menstruation in a proper way. This paper explored a tangible game for teenagers of different genders learning menstruation through collaborative playing. The game included five levels where users play together and learn the cause, products, symptoms of menstruation as well as try to judge some scenarios and listen to audios about menstruation. In our user study, we invited three groups of teenagers ages 11 to 16. Each group contained at least one male and one female, and we let them play the game freely. Teenagers were successfully able to play the game collaboratively, learn menstruation-related knowledge. The results revealed motivation differences related to gender, and after the game, teenagers demonstrated the observable change of the attitude towards menstruation.
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| 9. |
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| 10. |
- Man, Weizhen, et al.
(författare)
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Synthesis of novel CuO@Graphene nanocomposites for lubrication application via a convenient and economical method
- 2022
-
Ingår i: Wear. - : Elsevier. - 0043-1648 .- 1873-2577. ; 498-499
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Tidskriftsartikel (refereegranskat)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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| 11. |
- Nie, Jintao, et al.
(författare)
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SignFind: A Synchronized Sign Language and Chinese Character Teaching Game for Chinese Deaf Children Using Gesture Recognition
- 2022
-
Ingår i: CHI EA '22: Extended Abstracts of the 2022 CHI Conference on Human Factors in Computing Systems. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450391566 ; , s. 1-7
-
Konferensbidrag (refereegranskat)abstract
- This paper presents a targeted system to help Chinese deaf children learn both sign language and Chinese characters in early language learning. The system combines sign recognition and in-air writing techniques with games so that children can practice sign language and Chinese character writing at the same time. Sign recognition is used to assess the accuracy of sign language and in-air writing records the process of writing Chinese characters. In addition, the game adds to the learning fun and makes children more willing to complete learning tasks. We have developed a prototype to evaluate the effectiveness of a simultaneous Chinese sign language and Chinese character teaching system based on gesture recognition and in-air writing. We expect that this system will increase children's willingness and efficiency to learn sign language and Chinese characters, and eventually be used to assist in early language education for deaf children in the Chinese region.
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| 12. |
- Wang, Di, et al.
(författare)
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A strong enhancement of corrosion and wear resistance of polyurethane-based coating by chemically grafting of organosolv lignin
- 2024
-
Ingår i: Materials Today Chemistry. - : Elsevier. - 2468-5194. ; 35
-
Tidskriftsartikel (refereegranskat)abstract
- Corrosion and wear pose significant challenges to equipment operating in harsh environments. Thus, protective coatings are needed. Anti-corrosion and anti-wear coatings are traditionally fossil-based and often contain environmentally harmful additives. Achieving anti-corrosion and anti-wear coatings based on environmentally benign and sustainable materials is important and a significant challenge. This work focused on the development of organosolv lignin-based polyurethane (OS_lignin-PU) coatings. The coatings were synthesised and evaluated for corrosion protection using electrochemical impedance spectroscopy (EIS) and for wear properties using nanoindentation and nano scratch measurements. EIS revealed that the optimal lignin content for corrosion protection purposes in the OS_lignin-PU coatings was 15Â wt%. Moreover, addition of 15Â wt% lignin to the OS_lignin-PU coatings also enhanced their wear resistance, as evidenced by reduced thickness loss during tribometer tests. The nano scratch measurements revealed that OS_lignin-PU coatings containing 15Â wt% lignin exhibited the lowest scratch depth and friction coefficient. It is found that the developed lignin-containing coating exhibits remarkable corrosion and wear resistance, making it a promising sustainable material in various applications for pursuing sustainable development.
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| 13. |
- Wang, Di, et al.
(författare)
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Enhancing adhesion and durability: A biomimetic approach with dopamine-modified lignin-polydimethylsiloxane coatings
- 2024
-
Ingår i: Corrosion Science. - : Elsevier. - 0010-938X .- 1879-0496. ; 236
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Tidskriftsartikel (refereegranskat)abstract
- Corrosion causes significant challenges in industrial settings, leading to economic losses and safety concerns. Previously, we developed a lignin-polydimethylsiloxane (lignin-PDMS) coating that exhibited high corrosion resistance. However, the adhesion of the developed lignin-PDMS coating to carbon steel was limited, affecting its overall performance. To address this, we incorporated dopamine (DOPA), known for its strong adhesive properties, as a pre-treatment before applying the coating. It was found that the adhesion and corrosion resistance of lignin-PDMS coated steel could be improved by adjusting the pH value of the DOPA solution. The steel treated with pH 4.5 DOPA solution showed two times higher adhesion strength to the coating than non-treated steel. After the DOPA treatment, the coating can maintain high barrier property for at least 3 months in 1 M NaCl solution, which is even better than commercial gelcoat, demonstrating super corrosion protection. Quartz Crystal Microbalance with Dissipation (QCM-D) and X-ray Photoelectron Spectroscopy (XPS) analyses confirmed the DOPA deposition on the steel surface. Our findings show that the DOPA-lignin-PDMS system is an environmentally friendly and efficient solution for enhancing the durability of steels in corrosive environments.
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| 14. |
- Wang, Di, et al.
(författare)
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Green synergy: Eco-friendly, high-performance anti-corrosion and wear-resistant coatings utilizing organosolv lignin and polydimethylsiloxane
- 2024
-
Ingår i: Progress in organic coatings. - : Elsevier B.V.. - 0300-9440 .- 1873-331X. ; 190
-
Tidskriftsartikel (refereegranskat)abstract
- Anti-corrosion and anti-wear coatings provide an effective solution. However, traditional coatings are often fossil-based and contain heavy metals, posing environmental concerns. The drive for eco-friendly coatings has led to the exploration of green materials. This study combined lignin, an abundant organic material, and polydimethylsiloxane (PDMS), a known hydrophobic material, to address the challenges. Organosolv lignin was functionalised with (3-Aminopropyl)triethoxysilane (APTES), then chemically grafted on PDMS for the final coating synthesis. The optimised coating achieved through an eco-friendly process, exhibiting enhanced hydrophobicity and barrier properties, showing excellent long-term corrosion resistance in NaCl solution. The optimal coating formulation contained 15 wt% lignin and 40 wt% PDMS, demonstrating a high corrosion resistance (measured impedance of 1010 Ω·cm2), which remains effective even after 3 weeks of immersion in 1 M NaCl solution. This coating also showed good wear resistance, with a low friction coefficient evident from nano scratch tests.
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| 15. |
- Wang, Di, et al.
(författare)
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In-situ coating wear condition monitoring based on solid-liquid triboelectric nanogenerator and its mechanism study
- 2023
-
Ingår i: Nano Energy. - : Elsevier Ltd. - 2211-2855 .- 2211-3282. ; 112
-
Tidskriftsartikel (refereegranskat)abstract
- Various more or less wear-resistant coatings have been developed and used to protect metal substrates. However, the damage caused by wear is still a problem for most coatings. It is of great importance to monitor the wear of coatings in real-time during the applications. Recently reported wear monitoring methods (image processing, luminescent layers and the use of a sensing underlayer) require complex external equipment or additional coating preparation process steps, which limit their applications. As an emerging technology, a triboelectric nanogenerator (TENG) can convert mechanical energy into electricity, and it has been applied as a self-powered sensor. In this study, a new coating wear monitoring method is developed based on a solid-liquid TENG. The developed TENG generates electric signals corresponding to different wear states, which facilitates easy monitoring of the coating’s wear conditions. The results show that the surface composition change caused by wear is the main reason affecting the TENG signal output. The coating-liquid contact-separation motion generates real-time output signals that directly reflect the coating wear states without the need of any additional equipment. This study provides a promising new technology for in-situ coating wear monitoring.
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| 16. |
- Yin, Xuan, et al.
(författare)
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Achieving ultralow friction under high pressure through operando formation of PbS QDs/graphene heterojunction with 0D/1D nanostructure
- 2024
-
Ingår i: Carbon. - : Elsevier. - 0008-6223 .- 1873-3891. ; 218
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Tidskriftsartikel (refereegranskat)abstract
- In this work, ultralow friction (0.054) of graphene was achieved under high contact pressure (1.03 GPa) and atmosphere environment via the operando formation of PbS quantum dots (QDs)/graphene heterojunction at the frictional interface. It is found that PbS QDs are trapped in graphene nanosheets via shear-induced rearrangement for obtaining the PbS QDs/graphene heterojunctions, which provide an excellent rolling effect to lower friction. It is also found that the heterogeneous PbS QDs/graphene tribofilms have a strong Pb-enriched function and heterojunction nanorod phase. Our objective is to uncover the physical and chemical mechanisms governing the friction of 0D/1D nanostructures within PbS QDs/graphene heterostructures through our studies. This research will enhance our comprehension of nanomaterials' frictional behavior while offering valuable guidance and optimization strategies for their application in mechanical engineering and functional nanomaterials. Consequently, our efforts aim to foster the advancement of nanoscience and technology, leading to additional scientific and technological breakthroughs.
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| 17. |
- Yu, D., et al.
(författare)
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Internal Quality Nondestructive Detection and Sorting Principle of Walnut Based on Density and Digital Image : [基于比重和图像的核桃内部品质无损检测与分选]
- 2021
-
Ingår i: Nongye Jixie Xuebao. - : Chinese Society of Agricultural Machinery. - 1000-1298. ; 52:7, s. 373-378
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Tidskriftsartikel (refereegranskat)abstract
- Because the internal quality of walnuts is not easy to detect and a certain proportion of shelled walnuts in supermarkets are of poor quality, the principle of judging the internal quality of walnut according to the density was discussed, and the method and equipment of walnut sorting were studied. The principle of sorting walnuts was as follows: firstly, the walnut image collected by the camera was processed to estimate the volume of walnut; the weight of walnut was obtained; the gas pipe was selected according to the density of walnut to output gas; as a result, different walnuts fell into different containers. Walnut can also be detected and sorted according to density equivalent parameters. Secondly, when the walnut fell to the platform, the angle between its split plane and the platform was always about 60°. With this feature, the front and side cameras can be set in the correct orientation to obtain the contours of walnut, calculate the density of walnut and improve the sorting accuracy. In conclusion, this technology can indirectly detect the internal quality of walnut and promote intelligent and advanced detection. The sorting scheme had no adverse effect on walnut, working environment and operators. With the decrease of camera price, the decline of image processing cost and the improvement of computer operation speed, the cost of walnut sorter would be greatly reduced. The food processing plant would be able to arrange multiple work stations and multiple sorters at the same time, so as to meet the requirements of production efficiency when large quantities of walnut were sorted. Compared with the existing methods, the proposed method can realize nondestructive detection and had high academic value. © 2021, Chinese Society of Agricultural Machinery. All right reserved.
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| 18. |
- Zhao, Jun, et al.
(författare)
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Boosting the Durability of Triboelectric Nanogenerators: A Critical Review and Prospect
- 2023
-
Ingår i: Advanced Functional Materials. - : John Wiley & Sons. - 1616-301X .- 1616-3028. ; 33:14
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Forskningsöversikt (refereegranskat)abstract
- Triboelectric nanogenerators (TENGs) have attracted great interests in the development of sustainable energies and intelligent society. However, a big challenge for TENGs in practical applications is the unavoidable external mechanical abrasion and/or contaminant adsorption on the triboelectric materials, which leads to the significant decrease of the durability of TENGs and is urgently needed to be addressed. There are already a series of interesting progresses on the topic of the TENGs’ durability. In this study, reviewing the durability of TENGs via both the advanced materials/structure designing and the novel surface/interface engineering is focused upon, which includes choosing basic TENG materials, improving composites performance, optimizing structures, and designing triboelectric surfaces and interfaces. To get a better understanding of the durability of TENGs in published studies, the quantifiable levels of service life are also summarized including operation cycles, time, friction coefficient, and wear loss of triboelectric materials, where the boosting mechanisms are also discussed and summarized. Finally, the challenges as well as key strategies toward high durable TENGs are presented.
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| 19. |
- Zhao, Jun, et al.
(författare)
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Nanolubricant additives : A review
- 2021
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Ingår i: Friction. - : Springer. - 2223-7690 .- 2223-7704. ; 9:5, s. 891-917
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Forskningsöversikt (refereegranskat)abstract
- Using nanoadditives in lubricants is one of the most effective ways to control friction and wear, which is of great significance for energy conservation, emission reduction, and environmental protection. With the scientific and technological development, great advances have been made in nanolubricant additives in the scientific research and industrial applications. This review summarizes the categories of nanolubricant additives and illustrates the tribological properties of these additives. Based on the component elements of nanomaterials, nanolubricant additives can be divided into three types: nanometal-based, nanocarbon-based, and nanocomposite-based additives. The dispersion stabilities of additives in lubricants are also discussed in the review systematically. Various affecting factors and effective dispersion methods have been investigated in detail. Moreover, the review summarizes the lubrication mechanisms of nanolubricant additives including tribofilm formation, micro-bearing effect, self-repair performance, and synergistic effect. In addition, the challenges and prospects of nanolubricant additives are proposed, which guides the design and synthesis of novel additives with significant lubrication and antiwear properties in the future.
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| 20. |
- Zhao, Jun, et al.
(författare)
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Real-Time and Online Lubricating Oil Condition Monitoring Enabled by Triboelectric Nanogenerator
- 2021
-
Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 15:7, s. 11869-11879
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Tidskriftsartikel (refereegranskat)abstract
- An intelligent monitoring lubricant is essential for the development of smart machines because unexpected and fatal failures of critical dynamic components in the machines happen every day, threatening the life and health of humans. Inspired by the triboelectric nanogenerators (TENGs) work on water, we present a feasible way to prepare a self-powered triboelectric sensor for real-time monitoring of lubricating oils via the contact electrification process of oil-solid contact (O-S TENG). Typical intruding contaminants in pure base oils can be successfully monitored. The O-S TENG has very good sensitivity, which even can respectively detect at least 1 mg mL-1 debris and 0.01 wt % water contaminants. Furthermore, the real-time monitoring of formulated engine lubricating oil in a real engine oil tank is achieved. Our results show that electron transfer is possible from an oil to solid surface during contact electrification. The electrical output characteristic depends on the screen effect from such as wear debris, deposited carbons, and age-induced organic molecules in oils. Previous work only qualitatively identified that the output ability of liquid can be improved by leaving less liquid adsorbed on the TENG surface, but the adsorption mass and adsorption speed of liquid and its consequences for the output performance were not studied. We quantitatively study the internal relationship between output ability and adsorbing behavior of lubricating oils by quartz crystal microbalance with dissipation (QCM-D) for liquid-solid contact interfaces. This study provides a real-time, online, self-powered strategy for intelligent diagnosis of lubricating oils.
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| 21. |
- Zhao, Jun, et al.
(författare)
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Self-Powered, Long-Durable, and Highly Selective Oil-Solid Triboelectric Nanogenerator for Energy Harvesting and Intelligent Monitoring
- 2022
-
Ingår i: NANO-MICRO LETTERS. - : Springer Nature. - 2311-6706 .- 2150-5551. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Triboelectric nanogenerators (TENGs) have potential to achieve energy harvesting and condition monitoring of oils, the "lifeblood" of industry. However, oil absorption on the solid surfaces is a great challenge for oil-solid TENG (O-TENG). Here, oleophobic/ superamphiphobic O-TENGs are achieved via engineering of solid surface wetting properties. The designed O-TENG can generate an excellent electricity (with a charge density of 9.1 mu C m(-2) and a power density of 1.23 mW m(-2)), which is an order of magnitude higher than other 0-TENGs made from polytetrafluoroethylene and polyimide. It also has a significant durability (30,000 cycles) and can power a digital thermometer for self-powered sensor applications. Further, a superhigh-sensitivity O-TENG monitoring system is successfully developed for real-time detecting particle/water contaminants in oils. The O-TENG can detect particle contaminants at least down to 0.01 wt% and water contaminants down to 100 ppm, which are much better than previous online monitoring methods (particle> 0.1 wt%; water >1000 ppm). More interesting, the developed O-TENG can also distinguish water from other contaminants, which means the developed O-TENG has a highly water-selective performance. This work provides an ideal strategy for enhancing the output and durability of TENGs for oil-solid contact and opens new intelligent pathways for oil-solid energy harvesting and oil condition monitoring.
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| 22. |
- Zhao, Jun, et al.
(författare)
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The Tribological Performance of Metal-/Resin-Impregnated Graphite under Harsh Condition
- 2021
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Ingår i: Lubricants. - : MDPI. - 2075-4442. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Graphite-based composites are well recognized as ideal functional materials in mechanical seals, bearings of canned pumps, and electrical contact systems because of their outstanding self-lubricating ability, thermostability, and chemical stability. Working in harsh conditions is a huge challenge for the graphite materials, and their tribological properties and wear mechanisms are not well studied. In this study, the tribological performance of metal-impregnated graphite, resin-impregnated graphite, and non-metal-impregnated graphite under high temperature and high load are studied using a ball-on-disc tribometer. The results show that the metal-impregnated graphite (Metal-IG) has a stable friction regime and exhibits better anti-friction and anti-wear properties than that of resin-impregnated graphite (Resin-IG) and non-impregnated graphite (Non-IG) under extreme pressure (200~350 MPa) and high temperature (100–350 °C). The Metal-IG and Resin-IG can reduce the wear depth by 60% and 80%, respectively, when compared with Non-IG substrate. The impregnated materials (metal or resin) can enhance the strength of the graphite matrix and improve the formation of graphite tribofilm on the counterpart surfaces. Friction-induced structural ordering of graphite and slight oxidation of metal in the formed mechanically mixed layer is also beneficial for friction and wear reduction. This study demonstrates the tribological characteristics of impregnated graphite under harsh conditions and provides the experimental basis for the advanced usage of high-reliability and self-lubrication graphite composites.
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| 23. |
- Zhao, Jun, et al.
(författare)
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Two-dimensional (2D) graphene nanosheets as advanced lubricant additives : A critical review and prospect
- 2021
-
Ingår i: Materials Today Communications. - : Elsevier. - 2352-4928. ; 29
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Tidskriftsartikel (refereegranskat)abstract
- Graphene is a two-dimensional nanomaterial with a monolayer of atomic thickness. Due to its high specific surface area, weak interlayer interaction and good chemical stability, graphene has shown remarkable tribological properties as a lubricant additive. This review focuses on the research progress on graphene-based additives witnessed in recent years. Various synthesis methods of graphene nanomaterials have been displayed, and the review especially highlights the preparation processes of graphene using as a lubricant additive. The dispersion stability of graphene in lubricants is a key concern that has been presented. Besides physical and chemical modifications, a new dispersion method of structural regulation, which has obvious self-dispersed effect, is also discussed in detail. Furthermore, the lubrication mechanisms of graphene additives have been summarized, which will be highly beneficial to optimize the synthesis processes and to regulate the microstructures of graphene for achieving better lubrication. Finally, the challenges and outlook of the future studies on graphene additives are presented in the field of lubrication.
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| 24. |
- Zhao, Jun, et al.
(författare)
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Using Green, Economical, Efficient Two-Dimensional (2D) Talc Nanosheets as Lubricant Additives under Harsh Conditions
- 2022
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Ingår i: Nanomaterials. - : MDPI. - 2079-4991. ; 12:10
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional (2D) nanomaterials have attracted much attention for lubrication enhancement of grease. It is difficult to disperse nanosheets in viscous grease and the lubrication performances of grease under harsh conditions urgently need to be improved. In this study, the 2D talc nanosheets are modified by a silane coupling agent with the assistance of high-energy ball milling, which can stably disperse in grease. The thickness and size of the talc nanosheet are about 20 nm and 2 µm. The silane coupling agent is successfully grafted on the surface of talc. Using the modified-talc nanosheet, the coefficient of friction and wear depth can be reduced by 40% and 66% under high temperature (150 °C) and high load (3.5 GPa), respectively. The enhancement of the lubrication and anti-wear performance is attributed to the boundary adsorbed tribofilm of talc achieving a repairing effect of the friction interfaces, the repairing effect of talc on the friction interfaces. This work provides green, economical guidance for developing natural lubricant additives and has great potential in sustainable lubrication.
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| 25. |
- Zhu, Yanji, et al.
(författare)
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Nano SiC enhancement in the BN micro structure for high thermal conductivity epoxy composite
- 2021
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Ingår i: Journal of polymer research. - : Springer. - 1022-9760 .- 1572-8935. ; 28:10
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Tidskriftsartikel (refereegranskat)abstract
- Improving the heat dissipation efficiency of electronic products is the key to the design of many modern electronic and mechanical systems. Herein, we combined the 3D network fabricating with the way of micron-nano reinforcement to prepare high thermal conductivity and excellent thermal stability composites. Epoxy resin was used as the matrix, while the silicon carbide foam (f-SiC) as skeleton and the BN/nano-SiC as thermally conductive fillers. The thermal conductivity of the EP/f-SiC/BN/nano-SiC composite reaches 3.5 W·m− 1·K− 1, which is about 16.6 times higher than that of pure epoxy resin. The characterization results of TC and infrared thermography images indicate that the EP/f-SiC/BN/nano-SiC composite possess superior heat transport performance. Meantime, the EP/f-SiC/BN/nano-SiC composite have excellent thermal stability, the THRI of EP/f-SiC/BN/nano-SiC reaches 195.8℃, which is 21.3℃ higher than that of pure EP. This work would provide a new strategy for improving the TC of polymers by using other 3D skeletons and micron-nano fillers, and is conducive to the development of high thermal conductivity and excellent thermal stability materials.
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