分散染料的近期进展

介绍了分散料的近期进展，包括原有涂纶织物着色用散染料，超细旦纤维用分散染料，以及分散染料在喷射打印墨水和热转称铖像上的应用，展望了分散染料今后的发展方向。     

面向结构形状控制的驱动器结构参数与控制电压协同优化设计

飞机翼面结构形状的控制设计是提高飞机性能的关键技术。本文以压电纤维复合薄膜（Microfiber Composite,MFC）为驱动器,研究了协同优化设计MFC驱动器结构参数与控制电压以使飞机翼面结构具有理想形状的方法。以MFC的电极宽度、电极指间距、MFC厚度、压电陶瓷体积分数等驱动器结构参数以及控制电压为设计变量,以控制偏差最小为优化目标,以驱动器的击穿电压为约束,建立了驱动器结构参数与控制电压协同优化设计的模型;通过分析MFC驱动器结构参数对驱动性能的影响,给出了最优的驱动器结构参数;针对类似机翼翼面形状的平板扭转型面,给出了驱动器结构参数与控制电压协同的最优控制设计。设计结果表明：对于扭转变形,多个不同控制电压控制的型面均方差是相同控制电压控制均方差的45%,分析结果验证了本文所建立的协同优化设计方法的有效性。     

Preparation and magnetic properties of SrFe12O19/Ni0.5Zn0.5Fe2O4 nanocomposite ferrite microfibers via sol–gel process

SrFe₁₂O₁₉/Ni_0.5Zn_0.5Fe₂O₄ nanocomposite ferrite microfibers with diameters of 1–2 μm have been prepared by the sol–gel process. The SrFe₁₂O₁₉/Ni_0.5Zn_0.5Fe₂O₄ nanocomposite ferrites are formed after the precursor calcined at 850 °C for 2 h, fabricating from nanosized particles with a uniform phase distribution. The ferrite grain size increases with the calcination temperature. The magnetic properties for the nanocomposite ferrite microfibers are mainly influenced by the chemical composition and grain size. The nanocomposite ferrite microfibers obtained at 900 °C show the enhanced specific saturation magnetization (M_sh) of 64.8 Am² kg⁻¹, coercivity (H_c) of 146.5 kA m⁻¹ and remanence (M_r) of 33.6 Am² kg⁻¹ owing to the exchange–coupling interaction. This exchange–coupling interaction in the SrFe₁₂O₁₉/Ni_0.5Zn_0.5Fe₂O₄ nanocomposite ferrite microfibers has been discussed.     

Superstructure and mechanical properties of poly(L-lactic acid) microfibers prepared by CO2 laser-thinning

Poly(L-lactic acid) (PLLA) microfibers were obtained by a carbon dioxide (CO₂) laser-thinning method. A laser-thinning apparatus used to continuously prepare microfibers was developed in our laboratory; it consisted of spools supplying and winding the fibers, a continuous-wave CO₂-laser emitter, a system supplying the fibers, and a traverse. The laser-thinning apparatus produced PLLA microfibers in the range of 100-800 m min⁻¹. The diameter of the microfibers decreased as the winding speed increased, and the birefringence increased as the winding speed increased. When microfibers, obtained through the laser irradiation (at a laser power of 8.0 W cm⁻²) of the original fiber supplied at 0.4 m min⁻¹, were wound at 800 m min⁻¹, they had a diameter of 1.37 μm and a birefringence of 24.1×10⁻³. The draw ratio calculated from the supplying and winding speeds was 2000×. The degree of crystal orientation increased with increasing the winding speed. Scanning electron microscopy showed that the microfibers obtained with the laser-thinning apparatus had smooth surfaces not roughened by laser ablation that were uniform in diameter. The PLLA microfiber, which was obtained under an optimum condition, had a Young's modulus of 5.8 GPa and tensile strength of 0.75 GPa.     

A systematic review of the literature on plastic pollution in the Laurentian Great Lakes and its effects on freshwater biota

Plastic pollution is ubiquitous in freshwater systems worldwide, and the Laurentian Great Lakes are no exception. We conducted a systematic review to synthesize the current state of the literature on plastic pollution, including macroplastics (>5 mm) and microplastics (<5 mm), in the Great Lakes. Thirty-four publications were used in our systematic review. We found ubiquitous contamination of microplastics in surface water, with maximum abundances exceeding those in ocean gyres. There are also high levels of plastic contamination reported across benthic sediments and shorelines of the Great Lakes. Citizen science data reveals macroplastic across Great Lakes shorelines, with more than three million pieces of plastic litter recorded over a span of three years. We completed a second systematic review of plastic pollution and its impact on freshwater ecosystems in general to inform how plastic in the Great Lakes may impact wildlife. Among studies published in the literature, we found 390 tested effects, 234 (60%) of which were detected and 156 (40%) of which were not; almost all of the freshwater effects (>98%) were tested on microplastics. Based on a subset of these papers, we found that the shape and size of a particle likely affects whether an effect is detected, e.g., more effects are detected for smaller particles. Finally, we identify gaps in scientific knowledge that need to be addressed and discuss how the state of the science can inform management strategies.     

Effect of shrinkage reducing agent on pullout resistance of high-strength steel fibers embedded in ultra-high-performance concrete

The interfacial bond strength of long high-strength steel fibers embedded in ultra-high-performance concrete (UHPC) reinforced with short steel microfibers was investigated by conducting single-fiber pullout tests. In particular, the influence of the addition of a shrinkage-reducing to a UHPC matrix on the pullout resistance of high-strength steel fibers was investigated. The addition of a shrinkage-reducing agent produced a noticeable reduction in the fiber pullout resistance owing to the lower matrix shrinkage, although the reduction of pullout resistance differed according to the type of fiber. Long smooth and twisted steel fibers were highly sensitive to the addition of the shrinkage-reducing agent whereas hooked fibers were not. Among the various high-strength steel fibers tested, twisted steel macrofibers showed the highest interfacial bond resistance, although twisted fibers embedded in UHPC showed slip softening pullout behavior rather than the typical slip hardening behavior observed in mortar.     

定岛型海岛短纤维在超纤皮革中的应用

介绍了世界超纤皮革的发展及应用,并就定岛型海岛短纤维在超纤皮革中的应用 所产生的问题作了探讨。     

LDPE熔体粘度对PA6/LDPE超细纤维形貌的影响

以PA6/LDPE非相容体系进行共混纺丝,得到以PA6为分散相,LDPE为连续相的基体微纤型结构,用有机溶剂甲苯溶除LDPE制得PA6的超细纤维,并用扫描电镜(SEM)研究了其形貌。结果表明,在PA6/LDPE共混物中,PA6均匀分散在连续相LDPE形成海岛结构,且分散相尺寸较小,所制得的PA6超细纤维直径也较小;熔体粘度较低的LDPE更易溶于甲苯溶剂,且更易得到含PA6更高组成比的超细纤维。     

Amplified spontaneous emission from a single organic microfiber fabricated by melt electrospinning

We study gain amplification processes in a single organic microfiber fabricated by melt electro-spinning method. Smooth, individual and cylindrical fiber is obtained. The gain-induced response of the microfiber is found to depend sensitively on the fiber structure. In the homogeneous single fiber where loop cavity forms, high net optical gain of up to 31.4 cm⁻¹ results in spectral narrowing at the material gain peaks. In the case of strong optical feedback, which occurs in such a long microfiber, amplified spontaneous emission with a low threshold of 0.08 mW is obtained. The low threshold and high gain attribute also to the cylindrical cavity which supplies positive feedback.     

桔瓣型双组分纺黏水刺超纤技术及其应用

探讨桔瓣型双组分纺黏水刺超纤技术及其应用前景.介绍了桔辩型双组分纺黏水刺超纤技术的工艺原理及采用这种工艺生产超细纤维非织造布的优势,并阐述其产品的特点、应用领域及当前发展状况.指出:我国非织造技术与发达国家仍存在着较大差距,桔瓣型双组分纺黏水刺技术作为一种先进的非织造加工工艺,代表着当今世界非织造技术发展的一个重要方向,具有良好的市场前景.