SWCNT

SWCNT
  • 文章类型: Journal Article
    许多传热应用,如热交换器,太阳能槽式集热器,以及包括食品加工在内的领域,材料研究,和航空航天工程,利用混合纳米流体。与传统流体相比,混合纳米流体表现出显著增强的导热性。这项工作的目的是探索碳纳米管在具有Dufour和Soret效应的拉伸表面上的磁流体动力学生物对流流动下的流动和传热特征。此外,在存在热辐射和活动微生物的情况下,使用Prandtl流体模型研究了碳纳米管(SWCMT-MWCNT/C2H6O2与SWCMT-MWCNT/C2H6O2-H2O)流动的比较动力学。新颖的功能此外,重点也是检查微生物在混合物基础混合纳米流体的存在。为了检查Prandtl混合纳米流体在拉伸表面上的传热特征,在对边界条件进行建模时考虑了对流加热。已采用适当的相似性变换将维流控制方程转换为无量纲方程,并使用有效的方法获得了问题的解决方案,在MATLAB中准确和节省时间的bvp-4c技术。速度,温度,浓度和微生物谱已被证明在各种无量纲参数如倾斜磁化的不同影响下,混合对流,Dufour效应,Soret效应,热辐射效应,和生物对流刘易斯数。已经观察到提高磁化强度值(0.5≤M≤4),与碳纳米管的混合基础工作流体相比,混合对流(0.01≤λ≤0.05)和倾角(0°≤α≤180°)迅速增强了基于乙二醇的Prandtl杂化纳米流体(SWCMT-MWCNT/C2H6O2)的流体运动。SWCMT-MWCNT/C2H6O2-H2O)。提高热辐射(0.1≤Rd≤1.7)和Dufour数(0.1≤Du≤0.19)值可改善温度分布。此外,目前的结果与现有文献对皮肤摩擦结果有很好的一致性.
    Numerous heat transfer applications, such as heat exchangers, solar trough collectors, and fields including food processing, material research, and aerospace engineering, utilize hybrid nanofluids. Compared to conventional fluids, hybrid nanofluids exhibit significantly enhanced thermal conductivity. The aim of this work is to explore flow and heat transmission features under of magneto-hydrodynamic bioconvective flow of carbon nanotubes over the stretched surface with Dufour and Soret effects. Additionally, comparative dynamics of the carbon nanotubes (SWCMT - MWCNT/C2H6O2 with SWCMT - MWCNT/C2H6O2 - H2O) flow using the Prandtl fluid model in the presence of thermal radiation and motile microorganisms has been investigated. Novel feature Additionally, the focus is also to examine the presence of microorganisms in mixture base hybrid nanofluid. To examine heat transfer features of Prandtl hybrid nanofluid over the stretched surface convective heating is taken into consideration while modeling the boundary conditions. Suitable similarity transform has been employed to convert dimensional flow governing equations into dimensionless equations and solution of the problem has been obtained using effective, accurate and time saving bvp-4c technique in MATLAB. Velocity, temperature, concentration and microorganisms profiles have been demonstrated graphically under varying impact of various dimensionless parameters such as inclined magnetization, mixed convection, Dufour effect, Soret effect, thermal radiation effect, and bioconvection lewis number. It has been observed that raising values of magnetization (0.5 ≤ M ≤ 4), mixed convection (0.01 ≤ λ ≤ 0.05) and inclination angle (0° ≤ α ≤ 180°) enhance fluid motion rapidly in Ethylene glycol based Prandtl hybrid nanofluid (SWCMT - MWCNT/C2H6O2) when compared with mixture base working fluid of carbon nanotubes SWCMT - MWCNT/C2H6O2 - H2O). Raising thermal radiation (0.1 ≤ Rd ≤ 1.7) and Dufour number (0.1 ≤ Du ≤ 0.19) values improves temperature profile. Moreover, a good agreement has been found between the current outcome and existing literature for skin friction outcomes.
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  • 文章类型: Journal Article
    电子皮肤(e-skin)由于其多样化的潜在应用而引起了人们的极大兴趣,包括在生理信号检测中,健康监测,和人造喉咙。然而,传统电子皮肤的主要缺点是基材的附着力弱,灵敏度和拉伸性之间的不相容性,和它的单一功能。这些缺点限制了电子皮肤的应用,增加了其多功能集成的复杂性。在这里,将多层石墨烯层内和之间的交联SWCNT的协同网络直接滴涂到具有自粘附性的PU薄膜上以制造多功能电子皮肤。制备的电子皮肤的优异机械性能源于SWCNT在各种应变下以小和大变形保证的足够的导电路径。制备的电子皮肤表现出低的检测限,小至0.5%应变,以及在应变为0-30%时具有964的应变系数(GF)的灵敏度和拉伸性之间的相容性,和2743在30-60%的应变。在生理信号检测中的应用,电子皮肤展示了对微妙运动的检测,比如动脉脉搏和眨眼,以及大的身体运动,如膝关节弯曲,肘部运动,颈部运动。在人工咽喉应用中,电子皮肤集成了声音识别和声音发出,并显示不同的喉咙肌肉运动和声音信号采集和识别的不同单词之间的清晰和不同的反应,结合具有71dB(f=12.5kHz)的声谱响应的优越的声音发射性能。总的来说,对新型材料的综合研究,结构,属性,和机制在生理信号检测和人工咽喉应用中提供了有前途的潜力。
    Electronic skin (e-skin) has attracted tremendous interest due to its diverse potential applications, including in physiological signal detection, health monitoring, and artificial throats. However, the major drawbacks of traditional e-skin are the weak adhesion of substrates, incompatibility between sensitivity and stretchability, and its single function. These shortcomings limit the application of e-skin and increase the complexity of its multifunctional integration. Herein, the synergistic network of crosslinked SWCNTs within and between multilayered graphene layers was directly drip coated onto the PU thin film with self-adhesion to fabricate versatile e-skin. The excellent mechanical properties of prepared e-skin arise from the sufficient conductive paths guaranteed by SWCNTs in small and large deformation under various strains. The prepared e-skin exhibits a low detection limit, as small as 0.5% strain, and compatibility between sensitivity and stretchability with a gauge factor (GF) of 964 at a strain of 0-30%, and 2743 at a strain of 30-60%. In physiological signals detection application, the e-skin demonstrates the detection of subtle motions, such as artery pulse and blinking, as well as large body motions, such as knee joint bending, elbow movement, and neck movement. In artificial throat application, the e-skin integrates sound recognition and sound emitting and shows clear and distinct responses between different throat muscle movements and different words for sound signal acquisition and recognition, in conjunction with superior sound emission performance with a sound spectrum response of 71 dB (f = 12.5 kHz). Overall, the presented comprehensive study of novel materials, structures, properties, and mechanisms offers promising potential in physiological signals detection and artificial throat applications.
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  • 文章类型: Journal Article
    在这项工作中,通过合理设计CNT/Se/PEDOT:PSS三元纳米复合材料,成功设计了超高性能单壁碳纳米管(SWCNT)/Se纳米线(NW)/聚(3,4-亚乙基二氧噻吩):聚(4-苯乙烯磺酸盐)(PEDOT:PSS)三元热电(TE)纳米复合薄膜。CNTs的加入明显提高了复合膜的导电性,导致功率因数相对巨大的增长。PEDOT:PSS界面层均匀地附着在SeNW和CNT的两侧,形成一个紧密交织、相互联系的三维网络。因此,在434K下,含有26wt%CNT的样品的最大功率因数为863.83μW/(m·K2)。最终,使用优化的复合膜制造了由5个单元的独立复合膜条组成的柔性TE发电机原型,在44.7K的温度梯度下可以产生206.8nW的最大输出功率。本工作具有进一步的潜力,可用于柔性聚合物/碳TE纳米复合薄膜和器件。
    In this work, ultrahigh-performance single-walled carbon nanotube (SWCNT)/Se nanowire (NW)/poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) ternary thermoelectric (TE) nanocomposite films are successfully designed by rational design of CNT/Se/PEDOT:PSS ternary nanocomposites. The addition of CNTs apparently improves the electrical conductivity of composite films, resulting in a relatively huge growth of the power factor. The PEDOT:PSS interface layers uniformly attach on both sides of the Se NWs and CNTs effectively, forming a tightly interleaving and interconnected three-dimensional network. As a consequence, a maximum power factor of 863.83 μW/(m·K2) has been achieved for the sample containing 26 wt % CNTs at 434 K. Ultimately, a flexible TE generator prototype consisting of 5-unit freestanding composite film strips is fabricated using the optimized composite films, which can generate a maximum output power of 206.8 nW at a temperature gradient of 44.7 K. Therefore, the present work has a further potential to be used for the flexible polymer/carbon TE nanocomposite films and devices.
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  • 文章类型: Journal Article
    术中准确检测异氟烷麻醉的程度对及时避免过量异氟烷麻醉的风险具有重要意义。为了应对这一挑战,制作了四柄可植入微电极阵列(MEA),用于同步实时检测大鼠纹状体中的双模式信号[电生理信号和多巴胺(DA)浓度]。将SWCNT/PEDOT:PSS纳米复合材料改性到MEAs上,显着改善了MEA的电气和电化学性能。具有低阻抗(16.20±1.68kΩ)和小相位延迟(-27.76±0.82°)的改进的MEA的电气性能使得MEA能够以高信噪比(>3)检测尖峰触发。具有低氧化电位(160mV)的改性MEAs的电化学性能,低检测限(10nM),高灵敏度(217pA/μM),和宽线性范围(10nM-72μM)满足体内DA检测的具体要求。异氟醚的麻醉作用是通过抑制D2_SPNs(表达D2型DA受体的多刺投射神经元)的尖峰放电和局部场电位(LFP)的宽带振荡节律来介导的。因此,D2_SPN的尖峰放电率和LFP的功率可以共同反映异氟烷麻醉的程度。在异氟烷麻醉诱导的死亡过程中,我们发现电生理活动和DA释放受到强烈抑制,DA浓度的变化提供了有关此程序的更多详细信息。双模式记录MEA提供了异氟烷麻醉程度的检测方法和致命性过量异氟烷麻醉的预测方法。
    Accurate detection of the degree of isoflurane anesthesia during a surgery is important to avoid the risk of overdose isoflurane anesthesia timely. To address this challenge, a four-shank implantable microelectrode array (MEA) was fabricated for the synchronous real-time detection of dual-mode signals [electrophysiological signal and dopamine (DA) concentration] in rat striatum. The SWCNTs/PEDOT:PSS nanocomposites were modified onto the MEAs, which significantly improved the electrical and electrochemical performances of the MEAs. The electrical performance of the modified MEAs with a low impedance (16.20 ± 1.68 kΩ) and a small phase delay (-27.76 ± 0.82°) enabled the MEAs to detect spike firing with a high signal-to-noise ratio (> 3). The electrochemical performance of the modified MEAs with a low oxidation potential (160 mV), a low detection limit (10 nM), high sensitivity (217 pA/μM), and a wide linear range (10 nM-72 μM) met the specific requirements for DA detection in vivo. The anesthetic effect of isoflurane was mediated by inhibiting the spike firing of D2_SPNs (spiny projection neurons expressing the D2-type DA receptor) and the broadband oscillation rhythm of the local field potential (LFP). Therefore, the spike firing rate of D2_SPNs and the power of LFP could reflect the degree of isoflurane anesthesia together. During the isoflurane anesthesia-induced death procedure, we found that electrophysiological activities and DA release were strongly inhibited, and changes in the DA concentration provided more details regarding this procedure. The dual-mode recording MEA provided a detection method for the degree of isoflurane anesthesia and a prediction method for fatal overdose isoflurane anesthesia.
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  • 文章类型: Journal Article
    Helical wrapping by conjugated polymer has been demonstrated as a powerful tool for the sorting of single-walled carbon nanotubes (SWCNTs) according to their electronic type, chiral index, and even handedness. However, a method of one-step extraction of left-handed (M) and right-handed (P) semiconducting SWCNTs (s-SWCNTs) with subsequent cleavage of the polymer has not yet been published. In this work, we designed and synthesized one pair of acid cleavable polyfluorenes with defined chirality for handedness separation of s-SWCNTs from as-produced nanotubes. Each monomer contains a chiral center on the fluorene backbone in the 9-position, and the amino and carbonyl groups in the 2- and 7-positions maintain the head-to-tail regioselective polymerization resulting in polyimines with strictly all-(R) or all-(S) configuration. The obtained chiral polymers exhibit a strong recognition ability toward left- or right-handed s-SWCNTs from commercially available CoMoCAT SWCNTs with a sorting process requiring only bath sonication and centrifugation. Interestingly, the remaining polymer on each single nanotube, which helps to prevent aggregation, does not interfere with the circular dichroism signals from the nanotube at all. Therefore, we observed all four interband transition peaks (E11, E22, E33, E44) in the circular dichroism (CD) spectra of the still wrapped optically enriched left-handed and right-handed (6,5) SWCNTs in toluene. Binding energies obtained from molecular dynamics simulations were consistent with our experimental results and showed a significant preference for one specific handedness from each chiral polymer. Moreover, the imine bonds along the polymer chains enable the release of the nanotubes upon acid treatment. After s-SWNT separation, the polymer can be decomposed into monomers and be cleanly removed under mild acidic conditions, yielding dispersant-free handedness sorted s-SWNTs. The monomers can be almost quantitatively recovered to resynthesize the chiral polymer. This approach enables high selective isolation of polymer-free s-SWNT enantiomers for their further applications in carbon nanotube (CNT) devices.
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  • 文章类型: Journal Article
    Anisotropic composite films of polyaniline (PANI) with single-walled carbon nanotube (SWCNT) were prepared by in situ electropolymerization on highly oriented high-density polyethylene (HDPE) films. Polarized UV-vis and Raman spectra confirm the anisotropic arrangement of PANI molecular chains in the composite films. The conductivities of 16.6 ± 0.2 and 2.07 ± 0.2 S cm-1 have been obtained for doped PANI/0.8 wt % SWCNT measured along and perpendicular to the direction of the HDPE molecular chain, respectively. The response of PANI/0.8 wt % SWCNT films used as ammonia sensors is much higher along the chain direction of HDPE than that perpendicular to the chain direction of HDPE with an anisotropic ratio of 1.8 at 100 ppm ammonia. This is attributed to the well-ordered array of PANI/0.8 wt % SWCNT induced by the oriented HDPE films. Moreover, the high ammonia response for PANI/0.8 wt % SWCNT may be attributed to the charge-transfer effect between PANI and SWCNT.
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  • 文章类型: Journal Article
    The combination of gene therapy and chemotherapy has recently received considerable attention for cancer treatment. However, low transfection efficiency and poor endosomal escape of genes from nanocarriers strongly limit the success of the clinical use of small interfering RNA (siRNA). In this study, a novel pH-responsive, surface-modified single-walled carbon nanotube (SWCNT) was designed for the codelivery of doxorubicin (DOX) and survivin siRNA. Polyethylenimine (PEI) was covalently conjugated with betaine, and the resulting PEI-betaine (PB) was further synthesized with the oxidized SWCNT to form SWCNT-PB (SPB), which exhibits an excellent pH-responsive lysosomal escape of siRNA. SPB was modified with the targeting and penetrating peptide BR2 (SPBB), thereby achieving considerably higher uptake of siRNA than SWCNT-PEI (SP) or SPB. Furthermore, SPBB-siRNA presented substantially lower survivin expression and higher apoptotic index than Lipofectamine 2000. DOX and survivin siRNA were adsorbed onto SPB to form DOX-SPBB-siRNA, and siRNA/DOX was released into the cytoplasm and nuclei of adenocarcinomic human alveolar basal epithelial (A549) cells without lysosomal retention. Compared with SPBB-siRNA or DOX-SPBB treatment alone, DOX-SPBB-siRNA significantly reduced tumor volume in A549 cell-bearing nude mice, demonstrating the synergistic effects of DOX and survivin siRNA. Pathological analysis also indicated the potential therapeutic effects of DOX-SPBB-siRNA on tumors without distinct damages to normal tissues. In conclusion, the novel functionalized SWCNT loaded with DOX and survivin siRNA was successfully synthesized, and the nanocomplex exhibited effective antitumor effects both in vitro and in vivo, thereby providing an alternative strategy for the codelivery of antitumor drugs and genes.
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  • 文章类型: Journal Article
    Nanocables with a single-wall carbon nanotube (SWCNT) core and a ZnS shell were directly synthesized in one step through a thermal reaction method by using carbon, Zn, and FeS powder as starting materials. The as-fabricated nanocables were studied using scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. The nanocables have diameters of ~50 nm, lengths of several micrometers, and shell thickness of ~20 nm. TEM analysis revealed that the shell is polycrystalline wurtzite-type ZnS with good crystallinity, and the core of the nanocables is one to several SWCNTs. Raman results showed that the diameters of SWCNTs core are mainly distributed at 1.28 and 1.16 nm, with high quality and metallic character. A growth mechanism is proposed to explain the formation of the nanocables. This simple method may be applied to other SWCNTs-metal sulfide nanocables, which may have potential applications in photocatalysts, photocurrent, and other optical-electrical devices.
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  • 文章类型: Journal Article
    The wide application of nanoparticles will lead its release into the aquatic environment, which may alter the bioavailability and toxicity of other contaminants to aquatic organisms. This work aimed to study the effects of perfluorooctane sulfonate (PFOS), single-wall carbon nanotubes (SWCNT), and their mixture on PFOS accumulation, antioxidant defenses and acetylcholinesterase (AChE) activity in zebrafish. The fish was dissected after being exposed (24, 48, 72 and 96h) separately to PFOS, SWCNT and PFOS+SWCNT co-exposure. The bioaccumulation of PFOS in fish tissues (liver, intestines, gills and brain) decreased with increasing dosage of SWCNT, however, the opposite trend was observed in fish skin, which indicated that the bioavailability of PFOS changed by adsorption on SWCNT. Meanwhile, co-exposure induced more reactive oxygen species (ROS) than PFOS alone and enhanced the effect of PFOS on the superoxide dismutase (SOD), and catalase (CAT) and AChE activities. Furthermore, the integrated biomarker response (IBR) showed that co-exposure was the most stressful circumstance.
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  • 文章类型: Journal Article
    VP35 of Ebola viruses (EBOVs) is an attractive potential target because of its multifunction. All-atom molecular dynamics (MD) simulations and Molecular Mechanics Generalized Born surface area (MM/GBSA) energy calculations are performed to investigate the single-walled carbon nanotube (SWCNT) as an inhibitor in wild-type (WT) VP35 as well as in three primary mutants (K248A, I295A, and K248A/I295A) through docking the SWCNT in the first basic patch (FBP) of VP35. The SWCNTs of all the four systems effectively bind to the FBP. Interestingly, the sites and orientations of the SWCNT binding to the I295A mutant and K248A/I295A double mutants change significantly to accommodate the variation of the VP35 conformation. Moreover, the VDW can provide the major forces for affinity binding in all four systems.
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