SENSORS AND ACTUATORS A-PHYSICAL
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2025
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IF 4.9
Tao Luo,Dongyang Chen,Chongjie Jiang,Yingying Dai,Jinyang Le,Wei Zhou,Yu Xie
Ultrasound-actuated microrobots that incorporate entrapped microbubbles rely on acoustic streaming thrust for propulsion. While bubble size and resonance have been extensively studied, the role of opening size remains less understood. In this study, we numerically investigate how the opening size affects both streaming flow and the resulting thrust. Finite element analysis (FEA) reveals that although streaming velocity increases with oscillation amplitude and opening size, the generated thrust does not always scale proportionally. Counterintuitively, microbubbles with larger openings are more likely to produce greater thrust than those with smaller openings under identical acoustic excitation, despite generating weaker streaming flows. This phenomenon is experimentally confirmed using a microcantilever-based thrust measurement system. Our study provides key insights into the mechanics of microbubble-driven propulsion and highlight the the critical role of opening size in acoustic streaming thrust, offering valuable guidance for the design of next-generation microbubble-based acoustic microrobots for various biomedical applications.
研究领域:
声学
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微流控
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机器人学
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生物医学工程
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流体力学
✓ 已验证
DOI
高影响因子
TRIBOLOGY INTERNATIONAL
·
2024
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IF 6.1
Can Wu,Chen Zheng,Huijun Zhao,Mariyam Jameelah Ghazali,Yijun Wei,Zefei Zhu
A novel self-transport biomimetic composite texture on the guiding surface of thrust ball bearings was presented. The distribution and morphology of the grease fingers were analyzed using a self-developed fluorescent grease to evaluate the effects of different texture types on the lubrication state of the bearings. The results indicate that the self-transportation biomimetic composite texture bearing (BCB) exhibits the best lubrication performance. Compared with the non-textured bearing (NB), the overall vibration performance was improved by 55.7 %, the friction torque was decreased by 20.8 %, the slide/roll ratio was reduced by 67.2 %, and the grease storage capacity was increased by 130.5 %. The BCB bearing greatly improved the grease-starved state of the bearing, resulting from a more abundant secondary grease reservoir.
研究领域:
机械工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Bin Wang,Fuhan Liu,Huimin Nai,Haoqi Guo,Jian Zhang,Debin Xia,Kaifeng Lin,Yulin Yang
The controllability of thrust is paramount for electronically controlled solid propellants (ECSPs), which rely on the rapid redox reaction of hydroxylamine nitrate (HAN) as their primary oxidant. This study proposes a mechanism for HAN-electrolysis and electrode-induced solid propellant interphases (SPIs). The electrocatalytic oxidation of hydroxylamine in HAN plays a crucial role in the formation of interphases with copper, stainless steel, and titanium electrodes. The resulting hydroxyl radical oxidizes these electrodes to produce SPIs and also oxidizes polyvinyl alcohol to accelerate the thermal decomposition. The current density on the combustion process is significantly influenced by SPIs, determining whether the combustion state is electrolytically-led rapid combustion or pyrolytically-led slow combustion. SPIs with different electrodes are identified as Cu 2 (NO 3 )(OH) 3 , Fe(OH) 3 , and a mixture of the thermal decomposition of the propellants, respectively. Cu 2 (NO 3 )(OH) 3 has the smallest energy gap and impedance, resulting in the highest current density and optimal performance. The gas production of the Cu electrode is about 3.8 times that of the stainless steel electrode and about 6.7 times that of the Ti electrode at the same conditions. The in-situ SPIs are substituted with Cu 2 (NO 3 )(OH) 3 as the interface layer, leading to increased gas production for the copper electrode (by 3 times), stainless steel electrode (by 5.7 times), and titanium electrode (by 4.2 times). This research introduces the effects of SPIs and the electrocatalytic oxidation of hydroxylamine, offering a direction for improving the thrust and controllability of ECSPs.
研究领域:
化学工程
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材料科学
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航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2025
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IF 9.5
Chuntian Li,Hanwen Zhang,Zhidong Wang,Lian Li,Ruiqi Shen,Luigi T. De Luca,Wei Zhang
Hydroxylamine nitrate-based gel propellant (HAN-GP) materials have received attention due to their special electro-ignition properties, repeatable ignition characteristics, and green, pollution-free advantages. However, as a gel material, HAN-GP has higher conductivity than solid materials, which leads to reduced heat accumulation and may act as a conductor, thereby extending the ignition delay time and greatly limiting its application as a fuel for microthrusters. In this study, a copper-catalyzed HAN-GP was reported, which advances the decomposition temperature of the propellant and increases the heat transfer rate during the propellant's electrolytic process, thereby shortening ignition delay and achieving efficient combustion. By adding 0.2% copper powder, the decomposition temperature of the modified propellant is 77 °C lower than that of the baseline. At room temperature (30 °C), HAN-GP containing 0.2% copper powder (sample 3) increased the thermal diffusivity from 0.12 to 0.55 mm2 s−1 and the thermal conductivity from 0.08 to 0.16 W m−1 K−1, significantly enhancing its thermal conduction performance and heat transfer efficiency. Due to early thermal decomposition and rapid heat conduction effects, the ignition delay of sample 3 (300 ms) was reduced by 64% compared to the baseline (839 ms) at 225 V and 8 mL min−1. The total energy consumption of sample 3 decreased from 2500 J to 1800 J at 225 V and 4 mL min−1, which is a reduction of 28%. Additionally, it was found that its ignition energy could be further reduced to 30 J after multiple ignitions.
✓ 已验证
产品关联
DOI
高影响因子
ACS Biomaterials Science & Engineering
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2019
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IF 4.511
Han Wu,Lili Yang,Jun Qian,Deqing Wang,Yongkang Pan,Xuehong Wang,Saha Nabanita,Tingting Tang,Jun Zhao,Jie Wei
To improve the antibacterial and osteogenic activities of poly(etherketoneketone) (PEKK), concentrated sulfuric acid (H2SO4) suspension with silicon nitride (SN) microparticle was utilized to modify PEKK surface. Through sulfonation reaction, microporous coatings of PEKK/SN composites were created on PEKK surface, which were integrated with PEKK substrate. The results showed that the content of SN in the microporous coatings increased with the increase of SN content in H2SO4 suspension (PKS without SN, PKSC5 and PKSC10 with 5 and 10 wt % SN content in H2SO4) and that the surface roughness and hydrophilicity of microporous coatings on PEKK were significantly improved with the SN content increasing. In addition, the microporous coating of PKSC10 with high SN content exhibited excellent antibacterial activity due to the synergistic action of the presence of amino (−NH2) and sulfonic acid (−SO3H) groups as well as the improvement of protein absorption. Moreover, the microporous coating of PKSC10 obviously stimulated adhesion, proliferation, and osteogenic differentiation of rat bone mesenchymal stem cells. Furthermore, histological and push-out load evaluation indicated that the microporous coating of PKSC10 significantly promoted osteogenesis and osseointegration in vivo. The results suggested that the microporous coating of PKSC10 with high SN content display good biocompatibility, antibacterial and osteogenic activities, and osseointegration ability, which would have great potential for bone substitutes.
研究领域:
材料科学
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生物材料
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生物医学工程
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组织工程
✓ 已验证
DOI
PubMed
高影响因子
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