Recent Patents on Nanotechnology
·
2020
·Vol. 14
·期 1
·42-45
·
IF 0.977
Li Xiao-Xia,He Ji-Huan
Background: The patented bubble electrospinning, which is a simple and effective technique for mass-production of polymer nanofibers, has been studying extensively, but it is still under development. In the bubble electrospinning, multiple jets move from the positive electrode to the
receptor, a long distance between the two electrodes is needed to guarantee complete solvent evaporation, as a result a relative high voltage is needed. Objective: The aim of the present study is to use an auxiliary electrode and an auxiliary air flow to improve bubble electrospinning
with lower voltage and higher output than those by its traditional one. Methods: The modification of the bubble electrospinning with an auxiliary electrode and an auxiliary airflow is used to fabricate nanofibers. The auxiliary electrode is close to the positive electrode. The experiment
was carried out at room temperature with 8%PVA solution. The result was analyzed with a S4800 cold field scanning electron microscope (SEM, Hitachi S-4800, Tokyo, Japan). Results: The auxiliary electrode can generate a strong induced electric field force. With the action of airflow, the
jets will fly to the receptor instead of the auxiliary electrode. Conclusion: Both auxiliary electrode and auxiliary airflow are two important factors affecting the spinning process. It can reduce the spinning voltage and improve spinning efficiency.
研究领域:
材料科学
·
生物工程
✓ 已验证
DOI
PubMed
高影响因子
Processes
·
2022
·Vol. 10
·期 5
·997
·
IF 3.352
Ajuan Song,Sijia Zhao,Yijun Cao,Chao Li
The size of bubbles generated from a porous sparger is at least an order of magnitude larger than the pore diameter under the steady air pattern. Recent studies have shown that the bubble size can be significantly reduced when the steady air flow is replaced by an oscillatory pattern. However, the effectiveness of oscillatory air flow on reducing bubble size under different sparger characteristics is yet to be studied. This work fundamentally investigates the response of bubble size to sparger characteristics under an oscillatory air pattern by segregating the bubble formation subprocesses into bubble detachment and consequent coalescence. The results show that bubble size significantly decreased with hydrophilic plates regardless of contact angle, owing to depressed coalescence, while no impact was observed for a hydrophobic plate. The influence of the oscillatory air pattern on decreasing bubble size was weakened as the chamber volume was increased, and above a critical volume the bubble-formation process became similar with that under a steady air pattern. An optimum plate thickness was obtained for bubble generation by avoiding weeping, and meanwhile taking full advantage of the momentum force by the oscillatory airflow. The outcomes show that the oscillatory air pattern in determining bubble formation closely depends on the sparger characteristics, which should be appropriately determined.Keywords:bubble size;sparger configuration;oscillatory air pattern;coalescence
研究领域:
化学工程
·
流体力学
✓ 已验证
产品关联
DOI
高影响因子
Nature Communications
·
2023
·Vol. 14
·期 1
·1-11
·
IF 16.6
Xu Zijie,Cao Leo N. Y.,Li Chengyu,Luo Yingjin,Su Erming,Wang Weizhe,Tang Wei,Yao Zhaohui,Wang Zhong Lin
Real-time monitoring of flow turbulence is very difficult but extremely important in fluid dynamics, which plays an important role in flight safety and control. Turbulence can cause airflow to detach at the end of the wings, potentially resulting in the aerodynamic stall of aircraft and causing flight accidents. Here, we developed a lightweight and conformable system on the wing surface of aircraft for stall sensing. Quantitative data about airflow turbulence and the degree of boundary layer separation are provided in situ using conjunct signals provided by both triboelectric and piezoelectric effects. Thus, the system can visualize and directly measure the airflow detaching process on the airfoil, and senses the degree of airflow separation during and after a stall for large aircraft and unmanned aerial vehicles.
研究领域:
航空工程
·
流体力学
✓ 已验证
DOI
高影响因子
Smart Materials and Structures
·
2024
·Vol. 33
·期 4
·045002
·
IF 3.7
Xingzi Lan,Xinyu Chen,Xin Chen,Hao Fan,Hehui Zheng,Han Wang,Yadong Tang
Intelligent face masks play crucial roles in health monitoring and disease prevention, having attracted huge attention in recent years. However, most of the current intelligent face masks focus on monitoring single physical signal, which were unable to provide comprehensive information. Herein, an intelligent face mask with airflow and temperature sensing abilities, high-efficiency filtration and excellent antibacterial activity was proposed. The real-time airflow monitoring was realized by a triboelectric nanogenerator (TENG), which was composed of electrospun nanofibrous membrane and polydimethylsiloxane (PDMS) composite film. The fabricated electrospun nanofibrous membrane simultaneously played roles as tribo-positive material, filter and antibacterial membrane. The PDMS composite film prepared by co-blending and surface modification was applied as tribo-negative material. It was found that the combination of co-blending and surface modification enhanced the tribo-negative property of the PDMS film, resulting in an increment of output performance of TENG. The TENG integrated into a face mask could monitor respiratory rate and respiration intensity in real time. Additionally, the temperature sensing was achieved by a serpentine PDMS/laser-induced graphene temperature sensor. The temperature sensor exhibited a temperature coefficient of resistance of 0.316% °C−1, which could detect subtle temperature variations. Furthermore, the electrospun nanofibrous membrane exhibited excellent filtration performance and antibacterial activity. Therefore, the prepared intelligent face mask showed promising potential for healthcare applications.
研究领域:
生物医学工程
·
材料科学
·
健康监测
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2024
·Vol. 17
·期 10
·2190
·
IF 3.1
Xuemin Luo,Yanhui Jiao,Hang Li,Qi Liu,Jinfeng Liu,Mingwei Wang,Yong Liu
Transition metal dichalcogenides (TMDs), particularly monolayer TMDs with direct bandgap properties, are key to advancing optoelectronic device technology. WSe2stands out due to its adjustable carrier transport, making it a prime candidate for optoelectronic applications. This study explores monolayer WSe2synthesis via H2-assisted CVD, focusing on how carrier gas flow rate affects WSe2quality. A comprehensive characterization of monolayer WSe2was conducted using OM (optical microscope), Raman spectroscopy, PL spectroscopy, AFM, SEM, XPS, HRTEM, and XRD. It was found that H2incorporation and flow rate critically influence WSe2’s growth and structural integrity, with low flow rates favoring precursor concentration for product formation and high rates causing disintegration of existing structures. This research accentuates the significance of fine-tuning the carrier gas flow rate for optimizing monolayer WSe2synthesis, offering insights for fabricating monolayer TMDs like WS2, MoSe2, and MoS2, and facilitating their broader integration into optoelectronic devices.
研究领域:
材料科学
·
化学工程
·
光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL PHYSICS
·
2022
·
IF 2.552
Zhanqin Wang,Yongzhong Jia,Bing Liu,Yan Jing,Ying Yao
Flotation complexation extraction can effectively extract and separate lithium isotopes. The effects of nitrogen flow rate, bubble size, gas holdup, reaction flow pattern, aeration time, and temperature on the separation process were studied. In addition, the complex relationship and separation mechanism of lithium with 10-hydroxybenzoquinoline were discussed. Results show that nitrogen flow rate and bubble size significantly affected the flotation complexation extraction process. With an appropriate flow rate, we obtained a homogeneous regime pattern containing small and evenly distributed bubbles to achieve better separation efficiency and ensure a smooth extraction process. According to the slope method, lithium and 10-hydroxybenzoquinoline were complexed and extracted at a ratio of 1: 2. Compared with the traditional oscillating extraction, the bubble mass transfer mode in the flotation complexation extraction strengthened the complex extraction process and achieved higher extraction rate and separation efficiency.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 26
·e55580
·
IF 2.7
Zhenfeng Ma,Zhaoguang Zheng,Jun Zeng,Guodong Feng,Yihua Huang,Wenhui Luo,Minyou He,Jiaming Cui,Yi-Jun Liang
The practical application of fiber membranes prepared by electrostatic spinning requires a uniform thickness. However, the parameters involved in the spinning process are highly complex, particularly when it comes to precise control over membrane thickness. Hence, achieving a consistent and homogeneous thickness for fiber membranes has posed significant challenges thus far. To accurately predict membrane thickness during the spinning process and ensure consistent outcomes, this study employed polyvinylidene fluoride as the raw material and optimized electrostatic spinning preparation using an innovative airflow-assisted strategy. The as-proposed preparation strategy effectively enhances the volatilization of solvents within the jet, also promotes jet stretching through assistance from airflow, resulting in a more stable and homogeneous fiber diameter. Additionally, COMSOL simulations were utilized to provide rational explanations for these findings. By collecting multiple process parameters, including positive voltage, liquid supply speed, winding speed, and solution concentration, this study has successfully developed an artificial neural network (ANN) that exhibits reliable predictive capabilities for membrane thickness. Notably, the model demonstrates a remarkable goodness-of-fit with an R 2 value of 0.9981. Through the integration of ANN with electrostatic spinning technology, significant advancements have been achieved in accurately predicting and controlling the uniformity of electrostatically spun polymer fiber membranes.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2012
·Vol. 23
·期 2
·198-203
·
IF 10.179
Tianru Wu,Guqiao Ding,Honglie Shen,Haomin Wang,Lei Sun,Da Jiang,Xiaoming Xie,Mianheng Jiang
A simple but efficient strategy to synthesize millimeter-sized graphene single crystal grains by regulating the supply of reactants in the chemical vapor deposition (CVD) process is demonstrated. Polystyrene is used as a carbon source. Pulse heating on the carbon source is utilized to minimize the nucleation density of graphene on copper foil, while a gradual increase in the temperature of the carbon source and the flow rate of hydrogen is adapted to drive the continuous growth of the graphene grains. As a result, the nucleation density of graphene grain can be controlled to as low as ≈100 nuclei/cm 2 , and a single crystal grain can grow up to dimensions of ≈1.2 mm. Raman spectroscopy, transmission electron microscopy (TEM), and electrical-transport measurements show that the graphene grains obtained are of high quality. The strategy presented provides very good controllability and enables the possibility of large graphene single crystals, which is of vital importance for practical applications.
研究领域:
材料科学
·
物理化学
✓ 已验证
DOI
高影响因子
Polymers
·
2025
·Vol. 17
·期 3
·396
·
IF 4.9
Rongguang Zhang,Xun Chen,Han Wang,Jianfeng Sun,Shize Huang,Xuanzhi Zhang,Jiecai Long
Gas-assisted coaxial electrospinning (GACES) is a simple and general method for the mass preparation of coaxial nanofiber membranes, which has great industrial potential. However, in the manufacturing process, due to the bending instability of the jet in the electric field and the pulling effect of the gas flow field, the deposition uniformity of the fiber is still a big problem. Through finite element simulation analysis of the flow field in the manufacturing process and the construction of the jet mechanics model after adding the flow field, the influence mechanism of coaxial auxiliary flow on the fiber deposition area and its uniformity was successfully revealed in this research. Finally, the deposition area and thickness uniformity of coaxial fibers are increased by 3 times (the deposition area: 19.63 cm2→ 78.50 cm2) and 2.34 times (the standard variance: 3 μm2→ 10 μm2) by gas-assisted coaxial electrospinning. At the same time, the coaxial auxiliary gas flow also reduces the coaxial fiber diameter by 36.9% (the average fiber diameter: 241 nm ± 5 nm → 152 nm ± 23 nm) and the distribution range by 66% (the standard variance: 1.5 × 102nm2→ 51 nm2). This research provides a reliable idea and experimental basis for homogeneous preparation of coaxial nanofiber membranes.
研究领域:
材料科学
·
纳米技术
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2021
·
IF 5.816
Xiaoxiao Chen,Mengyao Liu,Lijuan Zhang,Yunshan Zhou,Enming Ping,Chunyan Ding
ZIF-67@NH 2 –SiO 2 composites were prepared by loading the metal-organic frameworks ZIF-67 on amino modified SiO 2 gel particles (NH 2 –SiO 2 , 80–100 mesh) through layer-by-layer self-assembly method. Systematic investigation on the effects of ZIF-67 loading amounts on NH 2 –SiO 2 packed stainless steel chromatographic column (specification 1.0 m×2.0 mm I.D.), the flow rate of He as carrier gas and the injection amount of mixed gas (H 2 /D 2 ) on the hydrogen isotope H 2 /D 2 separation performance at liquid nitrogen temperature, unraveled the optimal conditions for H 2 /D 2 isotope separation . The results showed that the optimal stationary phase materials under the optimized conditions can effectively separate H 2 and D 2 with separation resolution R = 1.52 and the separation time t = 10.15 min. The superior performance of the ZIF-67 is tentatively thought to be due to kinetic quantum sieving (pore size 3.3 Å) effect and chemical affinity sieving effect of Co ion in ZIF-67.
研究领域:
分析化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CRYSTAL GROWTH & DESIGN
·
2021
·
IF 4.076
Qichao Chen,Jiayi Chen,Xiao Xu,Zhehan Wang,Yamei Ding,Le Xiong,Beibei Zhu,Li Tao
Vapor–solid growth (VSG) is a cost-effective technique to synthesize Bi2Se3 materials with promising thermoelectric (TE) performance. In this work, smooth Bi2Se3 thin films with enhanced TE performance have been realized through regulating the carrier gas flow rate during the VSG process. The optimized morphology improves the electrical conductivity and decouples its interplay withthe Seebeck coefficient in Bi2Se3. As a result, our Bi2Se3 synthesized at 150 sccm gas flow rate exhibited a Seebeck coefficient around −100 μV K–1 and a power factor (PF) of 1.59 × 10–3 W m–1 K–2, which is higher than those of existing thin films and the single-crystal bulk form. This work provides guidance for the controllable preparation of Bi2Se3 thin films with low roughness and high TE performance for potential applications in micro-/nanodevices.
研究领域:
材料科学
·
热电学
✓ 已验证
DOI
高影响因子
LANGMUIR
·
2014
·
IF 4.384
Xiaohui Meng,Dong Qiu
Centimeter-sized two-dimensional (2D) colloidal single crystals of polystyrene (PS) particles were fabricated at the water/air interface by capillary-modulated self-assembly. Different from previous reports, in this work, emulsifier was used to facilitate the stress release during 2D colloidal crystal formation by adjusting the interparticle lateral interactions. With the assistance of compressed nitrogen flow, 2D hexagonal colloidal single crystals of centimeter size were obtained under appropriate emulsifier concentrations. A new method was also developed to transfer the 2D colloidal crystals from the air/water interface to the desired substrate without obvious disturbance. This new transferring method was proven not to be sensitive to surface wettability nor curvature, thus 2D colloidal single crystals with large areas could be obtained on different kinds of substrate.
研究领域:
材料科学
·
胶体化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）