Sn1- x Sm x O2 微纳米纤维的红外发射率与激光吸收性能：实验研究与第一性原理仿真

采用静电纺丝法结合热处理工艺制备了Sn_1-xSm_xO₂(x=0%,8%,16%,24%,质量分数,下同)微纳米纤维,表征了产物的物相、形貌、激光吸收性能和红外发射率,同时基于密度泛函理论的第一性原理对比分析了Sn_1-xSm_xO₂(x=0%,16%)的相关光电性质,进一步从电子结构角度解释了Sm³⁺掺杂对SnO₂红外发射率和激光吸收的作用机理。结果表明：经600℃煅烧后,Sn_1-xSm_xO₂均为单一金红石型结构,呈现出良好的纤维形貌,纤维相互交错,形成无规则三维网状结构,且各元素在纤维上分布均匀。随着Sm³⁺掺杂量的增大,产物在1064和1550 nm处的反射率逐渐降低,红外发射率先减小后增大。当x=16%时,在1064 nm处的反射率为53.9%,在1550nm处的反射率为38.5%,在8-14μm波段的红外发射率为0.749...     

The Effect of Electrospun Gelatin Fibers Alignment on Schwann Cell and Axon Behavior and Organization in the Perspective of Artificial Nerve Design

Electrospun fibrous substrates mimicking extracellular matrices can be prepared by electrospinning, yielding aligned fibrous matrices as internal fillers to manufacture artificial nerves. Gelatin aligned nano-fibers were prepared by electrospinning after tuning the collector rotation speed. The effect of alignment on cell adhesion and proliferation was tested in vitro using primary cultures, the Schwann cell line, RT4-D6P2T, and the sensory neuron-like cell line, 50B11. Cell adhesion and proliferation were assessed by quantifying at several time-points. Aligned nano-fibers reduced adhesion and proliferation rate compared with random fibers. Schwann cell morphology and organization were investigated by immunostaining of the cytoskeleton. Cells were elongated with their longitudinal body parallel to the aligned fibers. B5011 neuron-like cells were aligned and had parallel axon growth when cultured on the aligned gelatin fibers. The data show that the alignment of electrospun gelatin fibers can modulate Schwann cells and axon organization in vitro, suggesting that this substrate shows promise as an internal filler for the design of artificial nerves for peripheral nerve reconstruction.     

Optical fiber microwires and nanowires manufactured by modified flame brushing technique: properties and applications

The modified "flame brushing" technique has been used to manufacture microwires and nanowires from both silica and compound glasses. In this paper, the properties of the wires manufactured by this technique are presented. Applications fabricated from microwires are also discussed.     

纳米碳纤维技术的新进展

综述了已投入商业化运营的纳米碳纤维(CNF)生产工艺,诸如化学汽相沉积法(CVD)、静电纺丝法技术状况以及相关的生命周期分析数据。表明纳米尺度的碳纤维及其复合材料是一种多功能材料,具有优良的导电性、力学增强性和热性能。在纳米复合材料、贮氢和催化载体领域显示出了市场潜力。     

碳化硅纳米纤维改性C/C复合材料的力学性能

以电镀Ni颗粒为催化剂,采用催化化学气相沉积(CCVD)法,在单向炭纤维(CF)表面原位生长碳化硅纳米纤维(SiCNF),制备出SiCNF/CF共增强毡体。以此共增强毡体为前驱体,化学气相沉积碳后得到密度为1.7g/cm3的SiCNF改性C/C复合材料。复合材料力学性能测试表明,SiCNF改性可使C/C复合材料的抗弯强度、抗压强度和显微硬度明显提高。扫描电子显微镜和偏光显微镜观察表明,SiCNF改性处理改变了C/C复合材料中基体炭的结构,使其成为类似粗糙层(RL)或高织构的结构。     

Capture of sulfur dioxide from Claus tail gas using fiber-like alumina-based adsorbents

This paper describes the preparation of alumina fibers doped with CaO, MgO and La₂O₃ and reports their use as SO₂ adsorbents. These materials were characterized using electron microscopy, powder X-ray diffraction and infrared analysis and were examined for their ability to capture SO₂ selectively from gas mixtures containing large quantities of H₂O, CO₂ and some O₂ at temperatures in excess of 353 K. Overall, it was found that these adsorbents could remove SO₂ selectively and that they could be regenerated by treatment with an H₂S-containing gas at approximately 600 K. Adsorption capacity was retained over several cycles. Fourier transform infrared analysis showed that SO₂ was adsorbed as free SO₂ and also in a combined form as sulfite and sulfate species. In the regeneration step, the adsorbed sulfur species were reduced to elemental sulfur and H₂S or were desorbed as SO₂. It is proposed that the chemistry described here could be applied to design of a process for capture of all sulfur species typically found in a Claus-based sulfur recovery system.

     

纳米定性滤纸的研制与开发

采用纳米纤维和精制棉浆为主要原料,通过面层添加纳米纤维和浆内添加纳米纤维两种方式抄制定性滤纸。结果表明,纳米纤维的添加对提高纳米定性滤纸的过滤性能具有明显效果。     

Silicon carbide nano-fibers in-situ grown on carbon fibers for enhanced microwave absorption properties

Silicon carbide nano-fibers (SiCNFs) were in-situ grown on the surface of carbon fibers by catalysis chemical vapor deposition (CCVD) with Ni nano-particles as catalyst at 1000 °C. The phase composition, microstructures, oxidation resistance and microwave absorption properties of the SiCNFs coated carbon fibers were investigated by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermal gravity analysis (TGA) and Vector network analyzer, respectively. The results show that the as-grown nano-fibers which are mainly composed of β-SiC, present a withe-like morphology with diameter of 20–50 nm and aspect ratio of 100–150. Additionally, the TGA curves indicate that the oxidation resistance of the SiCNFs coated carbon fibers is significantly improved in comparison to the pure carbon fibers. Moreover, the investigation reveals that the microwave absorption properties of the SiCNFs coated carbon fibers are effectively enhanced. The reflectivity of the SiCNFs coated carbon fibers is less than −10 dB within the frequency ranging from 9.2 to 11.7 GHz and the lowest value of reflectivity can approach −19.9 dB when the thickness of specimen is 2 mm. While the reflection loss of the pure carbon fibers is higher than −2.1 dB within the whole band ranging from 2 and 18 GHz. The superior microwave absorbing performance of the SiCNFs coated carbon fibers is mainly attributed to the improved impedance matching as well as dissipation resulted from hopping migration. In conclusion, this study provides an effective modification approach to improve the microwave absorption properties of carbon fibers. Finally, the SiCNFs coated carbon fibers could be considered as a promising candidate in light-weight microwave absorbing materials.     

Enhanced electromechanical performance of carbon nano-fiber reinforced sulfonated poly(styrene-b-[ethylene/butylene]-b-styrene) actuator

In this paper, the carbon nano-fibers (CNFs) were used to improve the performance of sulfonated poly(styrene-b-[ethylene/butylene]-b-styrene) (SSEBS) composite actuator. The SSEBS actuator, which was developed in our previous study, does not have good electromechanical performance because the SSEBS ionic polymer is too flexible and soft. CNFs as a reinforcement for the polymer membranes greatly increased the bending performance of the SSEBS actuators. The surface and cross-sectional morphologies of the CNF-SSEBS actuators were investigated by SEM observation. The results show that carbon nano-fibers were homogeneously dispersed in the SSEBS polymer matrix without local agglomeration. The bending responses of the CNF-SSEBS composite actuators under step inputs and sinusoidal excitations were compared with those of the pure SSEBS actuator. The tip displacement of the CNF-SSEBS actuator was much faster and larger than that of the pure SSEBS actuator.     

功能化纤维素:PET纤维沸石分子筛复合材料对神经毒剂的解毒性研究(英文)

Presently activated carbon is used as an adsorptive material for chemical and biological warfare agents. It possess excellent surface properties such as large surface area, fire-resistance and plenty availability, but has disadvantages such as its heavy weight, low breathability (after adsorption of moisture) and disposal. In this paper, we propose to utilize novel electrospun polymeric nanostructures having zeolites as catalyst materials. In this respective, the electrospun polymer nanofibers would serve as the best possible substitutes to activated carbon based protective clothing applications. This is the first in the literature that reports the integration of these types of catalysts with nanofiberous membranes. Electrospinning of cellulose/polyethylene terephthalate (PET) blend nanofibers has been carried out. Zeolite catalysts (Linde Type A and Mordenite) for the detoxification of nerve agent stimulant-paraoxon, were prepared due to their relative simplicity of synthesis. The catalysts were then coated onto nanofiber membranes and their morphology was confirmed using SEM. This is the first report on the coating of nanofibers with zeolites and their successful demonstration against nerve agent stimulant. The UV absorption spectra clearly show the detoxification ability of the functionalized fibers and their potential to be used in textiles for protection and decontamination.