Micromachines
·
2015
·Vol. 6
·期 10
·1459-1468
·
IF 1.269
Jingmei Li,Zhou Liu,Haibo Huang,Ho Cheung Shum
In microfluidics, electric fields are widely used to assist the generation and the manipulation of droplets or jets. However, uncontrolled electric field can disrupt the operation of an integrated microfluidic system, for instance, through undesired coalescence of droplets, undesired changes in the wettability of the channel wall or unexpected death of cells. Therefore, an approach to control the distribution of electric fields inside microfluidic channels is needed. Inspired by the electro-magnetic shielding effect in electrical and radiation systems, we demonstrate the shielding of electric fields by incorporating 3D metallic coils in microfluidic devices. Using the degree of coalescence of emulsion drops as an indicator, we have shown that electric fields decrease dramatically in micro-channels surrounded by these conductive metallic coils both experimentally and numerically. Our work illustrates an approach to distribute electric fields in integrated microfluidic networks by selectively installing metallic coils or electrodes, and represents a significant step towards large-scale electro-microfluidic systems.Keywords:droplet coalescence;electric field;microfluidics;coils;shielding
研究领域:
工程学
·
物理学
·
生物学
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产品关联
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 42
·26211-26219
·
IF 3.108
Dandan Li,Lunan Guo,Na Yang,Yao Zhang,Zhengyu Jin,Xueming Xu
The properties and functionalities of chitosan are closely related to its degree of deacetylation (DD). This study aimed to determine the DD of chitosans, which were of identical molecular weight, by a proposed electro-analytical system based on inductive methodology. Statistically significant differences in electrical parameters, including terminal voltage (U′S) and λ (the ratio of primary voltage to U′S) were observed among chitosans with different DDs. Both U′S and λ were linearly correlated with the DD value, regardless of frequency, suggesting that these electrical parameters can be used to determine the DD of chitosan. More chitosan's coils contributed to higher measurement accuracy, but the change in measurement position showed no improvement. The highest linear coefficient of determination (0.9941) between DD and U′S was obtained by the experimental transformer with 100-turn chitosan's coils at a primary voltage of 10 V and a frequency of 400 Hz. This study explored the potential of an innovative electro-analytical system to determine the DD of chitosan.
研究领域:
生物化学
·
材料科学
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DOI
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 90
·49028-49039
·
IF 3.708
Peng Liu,Jiexing Liang,Shen Chen,Hailiang Zhang
A series of thermo-responsive rod–coil diblock copolymers with well-defined molecular weights have been synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. The rod–coil diblock thermo-responsive copolymer studied herein is poly(N-isopropylacrylamide)-b-poly[bis(N-hydroxyisopropyl pyrrolidone) 2-vinylterephthalate] (PNIPAm-b-PHIPPVTA), in which PHIPPVTA is a thermo-responsive rod-like polymer and exhibits an MW-dependent liquid crystalline (LC) phase behavior and MW-dependent thermo-responsive behavior. The bulk phase behaviors of the copolymers have been investigated by a combination of techniques including differential scanning calorimetry (DSC), polarized light microscopy (PLM), 1D and 2D wide-angle X-ray diffraction. The experiment results demonstrated that the phase structure of PNIPAm-b-PHIPPVTA is a hexatic columnar nematic phase when N43bHx and N151bHx with x ≥ 95 and 146, respectively. The thermo-responsive behaviors were investigated with turbidity measurements using UV-visible spectroscopy. The results showed that the cloud point of the diblock copolymers PNIPAm-b-PHIPPVTA can be adjusted by varying the length of the PHIPPVTA block. Only one phase transition temperature has been observed in the thermo-responsive rod–coil diblock copolymer PNIPAm-b-PHIPPVTA. Of special interest is the cloud point of block copolymers with longer flexible chain segment more strongly depending on the length of the semirigid segment compared to copolymers with shorter flexible chain segment.
研究领域:
高分子化学
·
材料科学
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产品关联
DOI
高影响因子
Scientific Reports
·
2015
·Vol. 5
·期 1
·1-7
·
IF 5.578
Liu Yanjuan,Liu Xiaowei,Zhan Yongjie,Fan Haiming,Lu Yang
Recently helical nanostructures such as nanosprings and nanocoils have drawn great interests in nanotechnology, due to their unique morphologies and physical properties and they may be potential building blocks in sorts of electromechanical, magnetic, photoelectronic and plasmonic devices at micro/nanoscales. In this report, multi-turns copper nanocoils were synthesized through a modified solvothermal method, in which the mixture of water and N-methyl-2-pyrrolidone (NMP) were selected as reaction medium and copolymer poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP/VA 64E) as reductant. In the liquid solution, nanosprings could be formed from relaxed nanocoils and demonstrated high elasticity. These nanocoils and nanosprings are of single crystalline structure, with the characteristics wire diameters ranging from tens to a few hundreds of nanometers and the ring/coil diameters mostly ~10–35 microns. Their growth and deformation mechanisms were then investigated and discussed along with that of previously reported single-turn copper nanorings. This work could be of importance for researchers working on synthesis and applications of novel 1-D helical nanomaterials and their functional devices.
研究领域:
纳米技术
·
材料科学
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产品关联
DOI
PubMed
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Ziwei Liu,Jianzheng Li,Yapeng Fu,Sijia Yu,Wenjun Li,Yiqing Yang,Jiajia Wang,Sihui Yu,Peiwen Yu,Kailiang Xu,Yajie Qin,Songlin Zhang,Huisheng Peng,Xuemei Sun
The brain undergoes constant dynamic deformations, which are intricately linked to its intrinsic properties and pathological states. However, continuous monitoring of these deformations presents significant challenges due to the limited temporal and spatial resolutions of conventional imaging techniques. Here, it is developed an implantable deformation array sensor capable of real-time, continuous monitoring and mapping of brain deformations. The sensor features microcoil arrays embedded in ultrathin films and operates based on the principle of mutual inductance, achieving exceptional temporal resolution (<100 µs) and distance resolution (<5 µm). It is implanted the sensor between the skull and the cortex and successfully tracked continuous brain deformations across four cortical sites in rat models. These experiments are conducted under scenarios of isoflurane inhalation, mechanical impacts, and intracranial hemorrhage, where such detailed monitoring and mapping has not been achieved previously. The results reveal that brain deformations dynamically vary over time in response to both physiological fluctuations and pathological events, with deformation amplitudes decreasing as the distance from the primary site increases. This innovative approach provides a novel platform for exploring brain dynamics and their associations with neurological disorders and disease progression.
研究领域:
神经科学
·
生物医学工程
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产品关联
DOI
高影响因子
POLYMER
·
2025
·
IF 4.5
Yifan Chen,Wentao Yuan,Yingxin Zhang,Hu-jun Qian,Zhong-yuan Lu,Shuxun Cui
According to the principle of polymer science, the gelation process of κ-carrageenan should start with polymer chains in a disordered coil conformation. However, the coil-helix model has been challenged by recent studies, which pointed out that in deionized water, κ-carrageenan exists in single-helix conformation rather than random coil. Here, we employ single-molecule force spectroscopy (SMFS) to investigate its conformation under different conditions at the single-chain level. Direct evidence for the existence of random coil state is obtained. In addition, it is found that coil-single helix transition can be induced by external Na + ions, which can screen the charges of the sulfated groups in κ-carrageenan. Thus, the mechanism of the first step of κ-carrageenan gelation is revealed, which lays a solid foundation for better understanding of the entire gelation process.
研究领域:
高分子科学
·
生物物理学
·
食品科学
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产品关联
DOI
高影响因子
Small
·
2025
·
IF 12.1
Yuan Guo,Yuping Duan,Shude Gu,Xiaoji Liu,Zeng Fan,Huifang Pang,Lujun Pan
The rational design of the aerogel pore structure facilitates the maximum excitation of the materials physicochemical properties, which enables the modulation of their electromagnetic performance. However, the controllable adjustment of the aerogel pore structure remains a significant challenge. Here, the freeze-thawing process and thermal annealing treatment are introduced to prepare reduced graphene oxide (rGO)/iron (Fe)/carbon nanocoil (CNC) aerogels. The composite aerogels with tunable pore structure are obtained by adjusting the content of CNC. Both experiments and simulations confirm that the pore structure with the addition of CNC presents a continuous 3D conductive network, which improves the conductivity loss and polarization loss. Meanwhile, the amorphous carbon structure within the CNC causes structural defects, which further enhance the polarization loss. Therefore, the rGO/Fe/CNC aerogel with optimized pore structure has lightweight and efficient electromagnetic wave absorption. At an ultra-low filling ratio of 0.8 wt%, the effective absorption bandwidth reaches 7.9 GHz and the optimal reflection loss is −43.5 dB. In addition, due to the 3D continuous network interwoven of aerogels and the temperature stability of carbon nanomaterials, composite aerogels have excellent thermal insulation, antifreeze performance, and hydrophobicity. This multifunctional absorber has great potential for application in complex and changing electromagnetic environments.
研究领域:
材料科学
·
电磁学
·
热力学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Materials Today Chemistry
·
2024
·
IF 6.7
Yuejing Sun,Li Yang,Qiujin Li,Peiduan Zhang,Jixian Gong,Zheng Li,Xiuming Liu,Jianfei Zhang
Flexible sensors have received increasing attention due to their various applications in health monitoring, artificial intelligence, and other fields. The simple fabrication of flexible sensing devices with high performances has been a research hotpot. In this work, an ionogel composite sensor combined with elastic knitted coil (EIC) is proposed as a wearable device to monitor human movement and related feature information. This sensor can be fabricated in a simple and easy protocol, which can work as a clothing accessary to track the wellness status parameters in daily life. After washing, the redundant gel originally embedded between the fibers was removed, improving the sensitivity of the sensor, which can provide accurate information about human joint movements and other physiological activities. The EIC sensor is in high sensitivity with superior working durability, which can provide continuous piezoresistive signals in detection mode. Other than the common joint bending movements (wrist, knee, elbow and finger) of human body, this sensor can also accurately output monitoring data on periocular, oral, and pharyngeal movements, providing information about human health status. Besides, a Morse codes transmission system can be constructed based on the piezoresistive outputs of this EIC sensor under different tapping modes, providing a new working platform in other related applications.
研究领域:
生物医学工程
·
材料科学
·
健康监测
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产品关联
DOI
高影响因子
Advanced Materials Technologies
·
2023
·Vol. 8
·期 15
·2300157
·
IF 6.8
Zhongyi Duan,Chuqiao Hu,Weijia Liu,Jinhai Liu,Zhengyu Chu,Weiqing Yang,La Li,Guozhen Shen
Fabrication of miniature-integrated devices combining energy harvester, energy storage, and various sensors via simple, fast, and efficient ways is strongly desired for the practical application of integrated smart systems. Herein, this work presents a simple one-step laser scribing method to prepare an all MXene-based seamlessly integrated system with integrated wireless charging coil, micro-supercapacitor, and photodetector in a small area of only 1.78 cm 2 . All the three modules in the integrated system are composed entirely of Ti 3 C 2 T x MXene and are connected with highly conductive MXene wires without additional welding or assembling operation. The energy is first received by the wireless charging coil and then stored in the Zn-ion micro-supercapacitor, which is subsequently used to drive the surface-modified (dodecyl triethoxysilane) DCTES-MXene-based photodetector, thus realizing the complete energy cycles. This work conceptually illustrates a simple method for designing and preparing integrated multifunctional wearable devices.
研究领域:
材料科学
·
能源技术
·
柔性电子
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产品关联
DOI
高影响因子
Journal of Physical Chemistry Letters
·
2022
·
IF 6.888
Yongsheng Luo,Ai-Ping Pang,Peizhi Zhu,Dayang Wang,Xiaolin Lu
Revealing interfacial shear-induced structural responsiveness has long been an important topic in that most fluids in nature and human life are in motion and cause interesting boundary phenomena. It is amazing how the polymer chain conformation or local structural features at a boundary change under the effective shear condition. In this study, microfluidic-assisted sum frequency generation (SFG) vibrational spectroscopy and all-atom molecular dynamics (MD) simulation are combined to reveal that the shear flow can effectively block the so-called thermal coil-to-globule transition of the poly(N-isopropylacrylamide) (PNIPAM) brushes on the solid substrate, and the normal coil-to-globule transition transfers to a coil-to-stretch one under shear flow with increasing ambient temperature. Such findings are attributed to the balance between the shear flow and the molecular interaction with respect to the polymer chains and adjacent water molecules, thus demonstrating the significant effect of the shear flow on the structural and dynamic behaviors of the polymer chains at the boundaries from the molecular level.
研究领域:
高分子科学
·
软物质物理
·
表面与界面科学
·
光谱学
·
流体力学
·
分子模拟
✓ 已验证
DOI
高影响因子
SENSORS AND ACTUATORS A-PHYSICAL
·
2024
·
IF 4.1
Luheng Wang,Gaige He
The assessment of buried flaws in the interlayer structure of curved metal is crucial to system safety. To improve the flexibility of eddy current sensor, an intrinsically flexible flaw sensing probe made of coil-shaped conductive polymer composite is proposed. The experimental data show that the response signal of the coil-shaped composite changes at the flaw and increases with the increases of flaw height/length, with a maximum sensitivity of 0.435 mV/mm for differential amplitude and 4.904 °/mm for differential phase. The results show that the height of the characteristic signals in the response signals reflects the change in flaw height, and the length of the characteristic signals in the response signals reflects the change in flaw length. The relative change rate of the coil-shaped composite is higher than that of a metal coil of the same structure. The above results have laid a preliminary foundation for using the coil-shaped composite to detect flaws.
研究领域:
材料科学
·
无损检测
✓ 已验证
产品关联
DOI
高影响因子
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
·
2020
·Vol. 646
·期 19
·1655-1659
·
IF 1.24
Luyu Wang,Jinguli Wen,Yuhang Wu,Junkuo Gao
Designing a humidity sensor with high performance to quick and accurate detect relative humidity (RH) is important in various applications. Consideration must be given to both the high response and the quick reversibility. Here, based on Quartz Crystal Microbalance (QCM) sensing platform, we utilized commercial graphene oxide as a sensing material, and added commercial carbon nanocoil to block the stacking of graphene oxide layers. The fabricated novel sensor possessed super high response (4618 Hz/97 % RH) and quick reversibility (2 s). This work not only expands the application of commercial carbon materials, but also achieves the development of high-performance humidity sensor with commercial potential.
研究领域:
材料科学
·
传感器技术
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）