Study on the Tip-less Electrospinning of Nanofibers with High Throughput and Their Patterned Deposition

电纺纳米纤维由于其优异的电学、力学、化学、光学特性和超高比表面积，在过滤、高性能传感器、生物骨架、药物传输与缓释和微纳米器件等领域有非常巨大的应用潜力和广阔市场前景，实现纳米纤维的批量制造是其产业化应用的关键。针对传统静电纺丝产量低下和组合式多针喷头阵列无法高效电纺问题，论文对无尖端喷头多射流纳米纤维宏量电纺技术进行详细的探索研究；针对电纺纳米纤维的无序性，采用两种方法改变收集板附近电场分布来实现纳米纤维图案化沉积（定向或定区域沉积），扩大纤维应用范围。 分析了组合式多针喷头阵列批量电纺纳米纤维的有效性，结果表明，由于针尖电场相互影响，中间针尖难以产生射流，而且电纺纤维直径差异大，无法高效率...Due to their remarkable characteristics of unique properties (optic, chemical and mechanical etc) and high surface surface to volume ratio, electrospun nanofibers will play important roles in future applications in filtering, high-performance sensor, bioscaffold, drug delivery, micro/nano devices and so on. Therefore, massive production of nanofibers is one of the key problems in their industriali...学位：工学博士院系专业：物理与机电工程学院机电工程系_测试计量技术及仪器学号：1822005140303

New MFL detection method based on differential peak extraction using dual sensors

为了提高管道、储罐漏磁检测的准确度、灵敏度,同时抑制噪声干扰,提出了一种双传感器差分峰值侦测的漏磁检测新方法。首先,对实际漏磁检测过程存在的背景噪声进行分析,研究了检测器振动、磁隙变化、磁轭泄漏等噪声源的共模特性;其次,利用缺陷漏磁场的分布特点构造了一种新型的差分侦测结构,该结构既可对噪声进行共模抑制,又可实现缺陷特征信号的差模提取;再次,依托磁偶极子模型,对所提方法的机理进行了分析,并讨论实现该方法所需要的约束条件及其检测灵敏度特性;最后,开展了仿真和物理实验,实验结果表明,该方法的噪声仅为传统X分量检测的5%,Y分量检测的26%,且检测敏感度提高了2倍。该方法为优化漏磁检测器结构、提高检测的可靠性及灵敏性提供了一个新的思路。In order to improve the accuracy and sensitivity of pipeline and storage tank magnetic flux leakage( MFL) detection,as well as suppress noise interference,a new MFL detection method based on differential peak extraction using dual sensors is proposed. Firstly,the background noise in actual MFL detection process is analyzed and the common mode characteristics of the noise sources,such as sensor vibration,magnet gap change,magnet yoke leakage and etc. are studied. Next,a new differential detection structure is built based on the distribution characteristics of the defect magnetic flux leakage,which can restrain the common-mode noise and realize the differential extraction of the defect feature signal. Then,based on the magnetic dipole model the mechanism of the proposed method is analyzed,the restraint conditions required for realizing the new method and the detection sensitivity characteristic of the method are discussed. Finally,simulation and experiment study were conducted,and the results show that the noise with the new method is only 5%of the one with traditional X-component detection,and 26% with traditional Y-component detection. Moreover,the detection sensitivity is improved twice. The proposed method provides a new strategy for optimizing the MFL detection sensor structure,and improving the detection reliability and sensitivity.国家自然科学基金(51177141);; 航空基金(2012ZD68003)项目资

Electrospun Aligned Polyethylene Oxide Nanofibers

采用一种新颖的纺丝工艺制备定向聚氧化乙烯纳米纤维.该工艺就是将两个平行的接地金属导体置于收集板的两侧,电镜图实验结果表明采用该一步法可以制得200~490nm左右的PEO定向纳米纤维,而且随着电极之间距离的增大,在拉伸的充分性和电场的共同作用下,纳米纤维先减小后增大.实验还证实定向纤维是电场而非结构作用的结果.An novel and facile electrospinning method, in which two parallel grounded metallic conductors are introduced to change electric field as auxilliary electrodes besides collector, is used to prepare oriented polyethylene oxide (PEO) nanofibers. SEMs of experiment results show that aligned nanofibers which diameters are around 200~490 nm can be achieved by this one-step method, and the diameters of nanofibers decrease at first when the distance is smaller than 2 mm, then increase if the distance is larger than 2 mm with the increasing distance between two parallel conductors as the combination of strectching sufficiency and decreasing electric field strength. It also can be verified that the aligned nanofibers mainly caused by changed electrostatic field and not by structure.海归学者科学研究基金资助;; 厦门大学创新项目研究基金项目资

Novel MFL method for pipeline crack no blind spot detection using composite excitation

管道是石油和天然气工业的重要组成部分,而轴向裂纹是管道安全运营的重要隐患。传统的漏磁检测技术(MFL)对管道中轴向裂纹的检测灵敏度不高,从而形成检测盲区。本文提出了一种利用复合激励的MFL检测新方法,可实现对轴向和周向缺陷的同步检测。首先,利用U型磁轭对管壁进行交直流复合磁化;直流磁化场直接作用于周向裂纹并形成有效的MFL检测信号,而交流磁化场则在管壁内形成垂直于磁化方向的均匀涡流场;当该涡流场受到轴向裂纹干扰时,将形成二次感生磁场的扰动,因此,新方法通过对管壁表面的漏磁场及二次感生磁场检测,同时获得周向和轴向两个方向的探测能力;最后开展仿真和实验,并分析了新方法中作用于轴向和周向裂纹的磁化场、涡流场和二次感生磁场的分布。结果表明,新方法只需通过一次扫描,即可以获得缺陷的轴向和周向特征,实现了对裂纹的无盲点检测。Pipelines are the critical components in oil and gas industry,axial cracks caused by stress corrosion and fatigue damage are the hidden danger of pipeline safe operation. The conventional magnetic flux leakage( MFL) detection technique is inadequate for accurately detecting the narrow axial crack in pipeline and forms detection blind region. In this paper,a new MFL detection method capable of simultaneously detecting both axial and circumferential defects is proposed utilizing DC-AC composite excitation. Firstly,the measured pipe wall is magnetized by DC-AC compound magnetic field using a U-shaped yoke. The DC magnetic field is directly acted on the circumferential crack and generates effective MFL detection signal. The AC magnetic field generates a uniform eddy current field perpendicular to the magnetization direction inside the pipe wall. When the eddy current field is disturbed by the axial crack,a secondary induced magnetic field is generated. Through detecting the surface magnetic flux leakage and secondary induced magnetic field,the new method can obtain the axial and circumferential crack detection capability simultaneously. Both simulations and experiments were conducted,the distributions of the magnetizing field,eddy current field and secondary induced magnetic field acting on the axial and circumferential cracks were analyzed. The results show that the proposed new method can detect both axial and circumferential cracks effectively with one pass scanning,the pipeline crack no blind spot detection is achieved.国家自然科学基金(51177141,51677158);; 航空基金(2012ZD68003)项目资

New NDT method for ferromagnetic materials based on differential permeability

利用微分磁导率变化特性,提出了一种可对材料的宏观缺陷进行快速扫查的无损检测新方法。首先,将铁磁性材料置于偏置磁化场环境下,缺陷将导致内部磁通的畸; 变;其次,磁通畸变进一步体现在材料表面微分磁导率分布的差异性;再次,通过特殊设计的微分磁导率检测探头,对材料表面微分磁导率的分布进行扫查;最后,; 由磁导率分布差异获得材料内部的不连续性信息,从而实现对缺陷的无损检测。开展了系列验证实验,结果表明,相对于传统的漏磁检测方法,新方法具有磁化强度; 低、磁通泄漏少、检测信号稳定的特点。新方法正、反面缺陷探测信号存在差异,在缺陷深度识别方面亦存在优势。A new non-destructive testing method is proposed to fast scan and detect; the macroscopic defects of materials using the variation characteristics; of the differential permeability of ferromagnetic materials. Firstly,the; ferromagnetic material,such as steel plate,is placed under the bias; magnetic field,and the defects in the material will inevitably lead to; the distortion of its internal magnetic flux. Secondly,the magnetic flux; distortion is further reflected in the difference of the differential; permeability distribution on the surface of the tested material.; Thirdly,using a specially designed probe,the distribution of; differential permeability on the surface of tested material is rapidly; scanned. Finally,from the difference of the differential permeability; distribution,the discontinuity information in the material can be; obtained,so as to realize the nondestructive testing of macroscopic; defects. Series of experiments were carried out,and the results show; that,compared with traditional magnetic flux leakage method,the new; method has the advantages of low magnetic intensity,less flux leakage; and stable detection signals. Moreover,the detection signals for the; front-side and back-side defects have obviously different distribution; characteristics,and the method also has obvious advantages in the field; of defect depth identification.国家自然科学基金; 福建省科技计划重大专

遗传算法在智能组卷系统中的设计与实现

为了能更好地解决组卷质量和组卷速度之间的矛盾,提出了一种基于分段整数编码的遗传算法。该算法在保证组卷预期效果的前提下,不仅搜索速度快,而且能够避免遗传算法中经常出现的"早熟现象",具有很好的收敛性和实用性。实践结果表明,该方法可以有效地解决智能组卷中的约束优化问题

Study on measurement and control system of FWM resin viscosity

纤维增强塑料(FRP)制品在航空航天、化工等行业应用非常广泛,但在其制造过程(如,预浸料和挤拉等生产工艺)中,纤维缠绕机械(FWM)上树脂粘度的在线测量和连续控制一直都是实际控制工程难以解决的难题。提出的FWM纤维树脂粘度控制系统采用单筒式测量法和模糊控制技术对树脂粘度进行测量控制的方案,不但结构简单、编程调试方便、能显示控制曲线,而且,能通过人机界面随时改变粘度的设定值和模糊控制器的参数,极大地改善了控制的性能,达到了预期的效果。Products of fiber reinforced plastic(FRP) are widely used in the industries of aerospace,chemistry and so on,but the online measurement and control of resin viscosity in fiber winding machine(FWM) is always a difficult problem to resolve in the production of FRP.A FWM resin viscosity control system is designed,in which Single-cylinder measurement solution and fuzzy control technology are applied,it is characterized by simple structure and easy programming and debugging.The value of viscosity and the parameter of fuzzy controller can be set through the friendly operation interface.The system greatly improves control effects

一种带有误差补偿项的折线线圈阻抗解析建模新方法

提出一种包含误差补偿项的任意折线线圈阻抗解析新模型。首先,在前人研究的基础上,通过定义外形位置因子,简化单矩形折线线圈的阻抗计算。其次,对多个单矩形折线线圈之间的相交耦合作用进行研究,建立串联等效电感模型。再次,讨论任意形状折线线圈的拆解和重构过程,研究重构过程的误差分布,并推导出误差补偿的数学表达;进而得到任意形状折线线圈的入射场阻抗及散射场阻抗的完整解析模型。最后,对螺线形折线线圈这一典型特例进行计算,绘制阻抗平面图,并利用高精度阻抗测试仪进行物理验证实验。结果表明,所提方法能有效补偿线宽因素带来的误差,可对置于导体上方的具有不同激励频率和提离的任意形状折线线圈的阻抗进行解析计算。国家自然科学基金(51177141);;航空基金(2012ZD68003

氯胺酮辅助硬膜外麻醉诱发喉痉挛1例

病例男,48岁,体重62kg,ASAⅠ级,3d前有上呼吸道感染病史,既往无其他疾病及药物过敏史,因急性阑尾炎拟在硬膜外麻醉下急诊行阑尾切除术。患者于术前30MIn肌注苯巴比妥钠100Mg和阿托品0.5Mg,入室后常规心电监护、吸氧、开放上肢静脉后,取左侧卧位,于T12~l1行硬膜外穿刺。穿刺置管顺利,注射试验剂量2%利多卡因5Ml,观察5MIn无全脊麻征象后追加1%利罗合剂10Ml,10MIn后测麻醉平面T8~l2。手术开始15MIn后,当提起阑尾、

New nondestructive test method with empirical research using local hysteretic loop characteristics

提出了一种利用局部磁滞回线特性的无损检测新方法。首先,研究了钢板内部缺陷对其动态磁导率分布的影响规律。其次,探讨了变励磁条件下局部磁滞回线的形成机理,并建立了动态磁导率与局部磁滞回线之间的关系模型。再次,根据所建立的关系模型,提出了一种利用局部磁滞回线特性实现对钢板缺陷进行无损检测的新方法,并给出检测系统的实现方案。最后,通过3d有限元法对实验模型进行仿真,并开展了一系列的物理实验进行了验证。结果表明,缺陷对钢板动态磁导率分布的影响显著,可利用局部磁滞回线特性来检测磁导率变化,从而达到检测内部缺陷,甚至背面缺陷的目的。所提新方法无需检测静态漏磁场磁感应强度,因此有效减小了磁化器体积。A new nondestructive test method based on local hysteretic loop characteristics is proposed in this paper.First of all,the influence law of the steel plate internal defects on the dynamic permeability distribution is studied,and the formation mechanism of the local hysteretic loop under the variable magnetic excitation condition is discussed.Secondly,the relation model between the dynamic permeability and local hysteretic loop is established.Furthermore,according to the proposed relation model,a new nondestructive test method of steel plate defects based on the local hysteretic loop characteristics is proposed,and the implementation scheme of the test system is given.Finally,the 3D finite element method was used to simulate the experiment model and a series of physical experiments were carried out to verify the proposed method.The results show that the steel plate defects have significant influence on the dynamic permeability distribution; the local hysteretic loop characteristics can be used to detect the permeability variation,and achieve the goal of detecting the internal defects of the steel plate,even the defects on the back of the steel plate.The proposed new method does not require to test the static leakage magnetic field,which reduces the volume of the magnetizing apparatus effectively.国家自然科学基金(51177141); 中央高校基本科研业务项目(2010121041); 航空基金(2012ZD68003)项目资