纳米TiO2陶瓷粒子对改善纺织品发射远红外线性能的测试

将陶瓷微粉添加入纺丝纤维可以提高织物的远红外发射性能。通过将纳米TiO粒子添加入聚乙烯醇薄膜进行远红外发射性能测试，研究了纳米TiO2粒子含量对纺丝纤维远红外发射性能的影响。测试结果表明，在纺丝纤维中添加陶瓷微粉，织物的远红线发射性能随陶瓷微粉含量增加呈线性增加。     

远红外织物的保健性能

远红外织物是８０年代中期研究开发出的一种通过高效吸收和发射远红外线而具有改善微循环、促进血液循环等功能的新型纺织品。本文通过研究实例综述了国内外近年来对远红外织物保健性能的研究成果。     

Sol-Gel自燃烧法制备MnZn铁氧体

用X线衍射仪(XRD)、扫描电子显微镜(SEM)和磁滞回线测试仪等实验测试手段,研究了Bi2O3B2O3-SiO2 (BBS)复合掺杂对MnZn铁氧体的晶体结构、显微形貌及磁性能的影响.实验结果表明,当BBS复合掺杂的质量分数从0增加到2.0％时,烧结样品的体积密度先减小后增大,ω(BBS) =2.0％时样品密度达到最大值.当复合掺杂量ω(BBS)＞0.5％时,BBS添加剂中各组分所形成的有效液相烧结促使尖晶石颗粒粒径的逐渐增大,样品的致密度不断提高,样品的初始磁导率和饱和磁感应强度均随着掺杂量的增加而不断增大,剩余磁感应强度和矫顽力则随之不断减小;当ω(BBS) =2.0％时,样品获得最佳磁性能.     

远红外织物的保健作用探析

远红外织物是近年来开发出的一种新型保温材料，它不但可以吸收外界能量而使自身的温度升高，而且可以高效发射出远红外线，同时还具有抑菌作用。本文在对红外辐射的理疗作用进行分析的基础上，从理论上讨论了远红外织物的保健作用。     

二磨时间对MnZn铁氧体结构和磁性能的影响

采用氧化物陶瓷工艺制备MnZn功率铁氧体,研究二次球磨时间对MnZn功率铁氧体微观结构和磁性能的影响.通过对铁氧体断面微观形貌的表征及密度、电阻率和磁特性的测试,结果表明,随着二次球磨时间的延长,MnZn功率铁氧体的密度、起始磁导率、饱和磁感应强度及电阻率均先增大后减小,损耗则先减小后增大.当二次球磨时间为2 h时,密度、起始磁导率、饱和磁感应强度及电阻率均达到最大值,总损耗最小且在25～120 ℃宽温范围内均低于350 kW/m~3.     

PTFE改性玻璃纤维织物磨损机理的SEM研究

目前，纤维及其织物材料的研究主要集中在其作为增强材料的应用方面，而纤维织物复合材料的摩擦磨损性能研究则较少。本文研究了PTFE(聚四氟乙烯)改性玻璃纤维织物复合材料的磨损机理，以便为玻璃纤维织物复合材料的进一步应用提供科学依据和参考。     

ZnO对锰锌铁氧体磁性能温度特性的影响

采用氧化物陶瓷工艺制备MnZn功率铁氧体,通过在不同温度下对铁氧体磁性能的测试,研究了ZnO含量对MnZn功率铁氧体磁性能温度特性的影响.结果表明,MnZn功率铁氧体室温下的起始磁导率和饱和磁感应强度随ZnO含量的增加呈先升高后下降的趋势,当w(ZnO)=12%时,起始磁导率和饱和磁感应强度达到最大值.同时,ZnO含量增加,起始磁导率-温度(μ_i-T)曲线Ⅱ峰所对应的温度点向低温移动,居里温度则一直降低.在100 kHz、200 mT条件下,随着ZnO含量的增加,常温下铁氧体的损耗先减小后增大,且损耗最低点温度也逐渐降低,并对应着μ_i-T曲线的Ⅱ峰位置.     

纳米磁性液体零泄漏密封保护器的实验研究

在某些特殊密封场合下,阀的密封优良与否具有重要意义,零泄漏就显得尤为重要。利用电磁式磁性液体零泄漏保护器搭建实验平台,记录了不同性状磁性液体在不同励磁电流下的耐压值,对比这些曲线之间的差异。实验表明:磁性液体的耐压值与磁感应强度成正比,在同等磁感应强度下,除去在点240 mA附近之外,耐压值的高低顺序依次为:样本1、样本2、样本3。根据电磁式保护器各磁场下的耐压情况,设计出三种不同尺寸的永磁环,研制出永磁式磁性液体密封保护器,扩大了保护器适应范围,提高了保护器的安全性能。总结出相关结论,对磁性液体密封中磁性液体的选取提供指导。     

外加纵向磁场对激光-MIG复合焊接接头形貌及微观组织的影响

研究了外加纵向磁场对SUS316L奥氏体不锈钢激光-稀有气体保护复合焊接接头成形特点、微观组织及显微硬度分布的影响。实验结果表明,在外加纵向磁场的作用下,接头的余高减小,熔宽增大,成形系数增大,截面宽而深。外加磁场改变了接头的热循环,使热影响区析出长条形δ-铁素体,抑制了晶粒的生长。外加磁场使熔池旋转,接头晶粒得到细化,结晶均匀性得到提高,显微硬度分布变得稳定。这种影响随着磁感应强度的增加而增强,随着接头深度的增大而减弱。     

太赫兹波在均匀磁化等离子体中的传播特性

研究了太赫兹波通过均匀磁化等离子体的传播特性,给出了太赫兹波衰减和相移随等离子体密度、碰撞频率、太赫兹波频率和磁感应强度的变化规律。等离子体电子密度越大,衰减和相移越大;随着碰撞频率的增大,电磁波的衰减先增加到峰值后逐渐减小,且随着磁感应强度的增加,衰减的峰值变大,峰值向碰撞频率减小的方向移动;当电子碰撞频率接近电磁波频率时等离子体对右旋极化波的衰减达到极大值。太赫兹波频率增大,衰减逐渐减小,而相移先增加后逐渐减小。     

Magnetic Electrospun Fibers for Cancer Therapy

Iron oxide nanoparticles (IONPs) for magnetic hyperthermia in cancer treatment have recently gained substantial interest. Unfortunately, the use of free IONPs still faces major challenges such as poor tumor targetability, high variability in the amount of IONPs taken up by the tumor and the IONP leakage from dead cancer cells into the surrounding healthy tissues. The present work reports on electrospun fiber webs, heavily loaded with 50 nm sized IONPs. The high loading capacity of the fibers enables significant heating of the environment upon applying an alternating magnetic field. Furthermore, magnetic fibers can be repeatedly heated without loss of heating capacity or release of IONPs. Upon functionalization of the fiber surface with collagen, human SKOV‐3 ovarian cancer cells attached well to the fibers. Applying an alternating magnetic field during 10 minutes to the fiber webs killed all fiber‐associated cancer cells. Killing the cells using this method seemed more efficient compared to the use of a warm water bath. As the fiber webs can be i) loaded with a well‐controlled amount of IONPs and ii) localized in the body by Magnetic Resonance Imaging, magnetic electrospun fibers may become promising materials for a highly reproducible (repeated) heating of cancer tissues in vivo.     

红外空心布拉格光纤损耗特性的研究

采用半导体玻璃/有机聚合物作为材料,利用禁带效应,设计了传输波段中心波长位于10.6μm处的空心Bragg(布拉格)光纤。利用COMSOL Multiphysics仿真软件,分析了径向包层数对基模(HE11)传输损耗的影响。结果表明,当包层数增至20层时,其损耗值已降至0.051 4dB/m,明显优于普通硫系化合物光纤最低所能达到的0.6dB/m。这种Bragg光纤既可用于医用高功率二氧化碳激光传输,也适用于远距离红外传输。     

大纤芯红外带隙型光子晶体光纤研究

针对一般红外光纤存在材料损耗高、制备工艺复杂、传输性能和输出光束质量差等问题,提出了一种适合CO2(二氧化碳)激光传输的新型大纤芯红外PBG-PCF(光子带隙型光子晶体光纤),该光纤由三角形结构光子晶体在中心抽掉19根毛细管空气孔形成大纤芯。利用PWM(平面波展开法)分析得到了传输波长为10.6μm的CO2激光的光纤带隙图;再利用基于全矢量有限元法的仿真软件COMSOL Multiphysics分析其损耗特性。结果表明,这种结构的PBG-PCF与现有的红外光纤相比,传输10.6μm CO2激光时的损耗更小,约为0.08dB/km,可满足医用传输大功率CO2激光的需要。     

Fused taper infrared optical fiber couplers in chalcogenide glass

We have fabricated low loss, high coupling ratio bidirectional optical couplers for infrared light using multimode step-index chalcogenide fiber. Using a fusion technique similar to that commonly employed with silica fibers, we have found a temperature regime where fusion can occur while interdiffusion of the core and cladding materials will not. The resultant device has a roughly 3:1 coupling ratio, less than 0.3 dB of excess insertion loss, and preserves the guided modes of the fiber intact     

Infrared Optical Fibers

A state of the art review of nonsilica based infrared fibers is presented. Two types of fiber materials have been investigated--crystals and glasses. Crystal fiber work appears to be focused on development of short haul CO/sub 2/ laser power delivering lines at 10.6 µm. The maximum delivering power of the CW CO/sub 2/ laser has reached up to about 100 W by the polycrystalline KRS-5 fiber. A number of glass fibers are being developed in fluorides, sulfides and heavy metal oxides. The best optical attenuation of each glass fiber has been respectively reduced to 21 dB/km at 2.55 µm for ZrF/sub 4/-based glass fiber with a core-clad structure, 78 dB/km at 2.4 µm for As-S unclad glass fiber, and 13 dB/km at 2.05 µm (70 dB/km at 2.40 µm) for GeO/sub 2/-Sb/sub 2/O/sub 3/ glass fiber with a core-clad structure. Recent progress of these infrared fibers offers great potential for new wavelength fiber finks operating in the 2-10 µm region which have not been realized by silica-based fiber.     

Magnetic and photomagnetic properties of polycrystalline wide-gap semiconductor Cd1-xMnxTe thin films

The magnetic and photomagnetic properties of polycrystalline Cd_1-xMn_xTe thin films prepared by radio frequency (rf) sputtering have been investigated. Magnetization measurements were carried out using a rf superconducting quantum interference device magnetometer in the temperature range of 1.8∼300K at various magnetic fields up to 5.5 T. For temperatures above 40K, Curie-Weiss behavior was observed with a negative Weiss constant indicating predominantly antiferromagnetic interactions. Spin-glass transitions occurred at low temperatures. Photoinduced magnetization has been observed when the sample was illuminated by unpolarized light from an optical fiber.     

As-S多模红外光纤的双坩埚法制备工艺

对As-S芯皮(纤芯—包层)结构多模光纤的制备工艺进行了研究。通过设定芯料管和皮料管压力比、拉丝速度和拉丝温度等工艺参数,可获得不同直径以及芯径皮厚比的多模As-S芯皮结构红外光纤。当双坩埚尺寸固定,光纤芯径会随着芯料管和皮料管压力比的增大而增大,而皮厚则会减小;但当皮料管压力减小到一定程度并保持一定时,光纤芯径和皮厚受芯料管压力改变的影响就不明显了;一般拉丝速度越快,直径就越小。由于红外玻璃原料中杂质S—H的含量对As-S红外光纤损耗的影响比较显著,因此应着力提高原料纯度,降低As-S红外光纤损耗,以实现As-S红外光纤的国内产业化。     

Controlled Sub‐Micrometer Hierarchical Textures Engineered in Polymeric Fibers and Microchannels via Thermal Drawing

The controlled texturing of surfaces at the micro‐ and nanoscales is a powerful method for tailoring how materials interact with liquids, electromagnetic waves, or biological tissues. The increasing scientific and technological interest in advanced fibers and fabrics has triggered a strong motivation for leveraging the use of textures on fiber surfaces. Thus far however, fiber‐processing techniques have exhibited an inherent limitation due to the smoothing out of surface textures by polymer reflow, restricting achievable feature sizes. In this article, a theoretical framework is established from which a strategy is developed to reduce the surface tension of the textured polymer, thus drastically slowing down thermal reflow. With this approach the fabrication of potentially kilometers‐long polymer fibers with controlled hierarchical surface textures of unprecedented complexity and with feature sizes down to a few hundreds of nanometers is demonstrated, two orders of magnitude below current configurations. Using such fibers as molds, 3D microchannels are also fabricated with textured inner surfaces within soft polymers such as poly(dimethylsiloxane), at dimensions and a degree of simplicity impossible to reach with current techniques. This strategy for the texturing of high curvature surfaces opens novel opportunities in bioengineering, regenerative scaffolds, microfluidics, and smart textiles.     

Fabrication and properties of polymer optical fibers containingNd-chelate

Graded-index poly(methyl methacrylate) optical fibers (GI POF) containing a Nd-chelate have been fabricated. The absorption spectrum of the fiber exhibited several strong bands in the visible and infrared regions. We have observed infrared fluorescence (0.90, 1.06, and 1.3 μm) of the Nd³⁺ ion of the fiber at room temperature when it was pumped with an Ar⁺-pumped dye laser at 580 nm     

Current distance relations for fiber stimulation with pointsources

The following results are based on computer simulations and on activating function analysis. In the near field, denervated muscle fibers as well as nerve fibers with a sealed ending are easier to stimulate in the central region than with electrodes close to the end. When electrode-fiber distance is increased, the electrode location for optimal stimulation efficacy shifts from a central position to a region beyond the fiber end for cathodic stimulation and to a position above the terminating part of the fiber for anodic currents. The phenomenon becomes more pronounced with increasing distance between the electrode and fiber axis, because in the far field, the current-distance relation changes from quadratic to cubic, whereas stimulation at the fiber end obeys a rather constant quadratic law.