Dual-channel fiber-optic surface plasmon resonance sensor with cascaded coaxial dual-waveguide D-type structure and microsphere structure

To address the restriction of fiber-optic surface plasmon resonance(SPR) sensors in the field of multi-sample detection, a novel dual-channel fiber-optic SPR sensor based on the cascade of coaxial dual-waveguide D-type structure and microsphere structure is proposed in this paper. The fiber sidepolishing technique converts the coaxial dual-waveguide fiber into a D-type one, and the evanescent wave in the ring core leaks, generating a D-type sensing region;the fiber optic fused ball push technology converts the coaxial dual waveguides into microspheres, and the stimulated cladding mode evanescent wave leaks, producing the microsphere sensing region. By injecting light into the coaxial dual-waveguide middle core alone, the sensor can realize single-stage sensing in the microsphere sensing area;it can also realize dual-channel sensing in the D-type sensing area and microsphere sensing area by injecting light into the ring core. The refractive index measurement ranges for the two channels are 1.333–1.365 and 1.375–1.405, respectively, with detection sensitivities of 981.56 nm/RIU and 4138 nm/RIU. The sensor combines wavelength division multiplexing and space division multiplexing technologies, presenting a novel research concept for multi-channel fiber SPR sensors.

Comparative research on three types of coaxial slow wave structures

This paper studies three types of coaxial slow wave structures （SWSs）： （1） with ripples on both the inner and outer conductors; （2） with ripples on the outer conductor and smooth on the inner one; and （3） with ripples on the inner conductor and smooth on the outer one. The frequencies, coupling impedances, time growth rates and beam-wave interaction efficiencies of the three types of coaxial SWSs are obtained by theoretical analysis. Moreover, the relativistic Ccrenkov generators （RCGs） with the three types of coaxial SWSs are simulated with a fully electromagnetic particle- in-cell code, and the results verify the theoretical analysis. It is proved that the RCG with double-rippled coaxial SWS has the highest conversion efficiency and the shortest starting time.

Coaxial electrohydrodynamic printing of core–shell microfibrous scaffolds with layer-specific growth factors release for enthesis regeneration

The rotator cuff tear has emerged as a significant global health concern.However,existing therapies fail to fully restore the intricate bone-to-tendon gradients,resulting in compromised biomechanical functionalities of the reconstructed enthesis tissues.Herein,a tri-layered core–shell microfibrous scaffold with layer-specific growth factors(GFs)release is developed using coaxial electrohydrodynamic(EHD)printing for in situ cell recruitment and differentiation to facilitate gradient enthesis tissue repair.Stromal cell-derived factor-1(SDF-1)is loaded in the shell,while basic fibroblast GF,transforming GF-beta,and bone morphogenetic protein-2 are loaded in the core of the EHD-printed microfibrous scaffolds in a layer-specific manner.Correspondingly,the tri-layered microfibrous scaffolds have a core–shell fiber size of(25.7±5.1)μm,with a pore size sequentially increasing from(81.5±4.6)μm to(173.3±6.9)μm,and to(388.9±6.9μm)for the tenogenic,chondrogenic,and osteogenic instructive layers.A rapid release of embedded GFs is observed within the first 2 d,followed by a faster release of SDF-1 and a slightly slower release of differentiation GFs for approximately four weeks.The coaxial EHD-printed microfibrous scaffolds significantly promote stem cell recruitment and direct their differentiation toward tenocyte,chondrocyte,and osteocyte phenotypes in vitro.When implanted in vivo,the tri-layered core–shell microfibrous scaffolds rapidly restored the biomechanical functions and promoted enthesis tissue regeneration with native-like bone-to-tendon gradients.Our findings suggest that the microfibrous scaffolds with layer-specific GFs release may offer a promising clinical solution for enthesis regeneration.

Innovative coaxial high-temperature thin-film sensor with core-shell structure surpassing traditional multilayer films

High-temperature thin-film sensors(TFSs)often suffer from inadequate tolerance to elevated temperatures.In this study,an innovative approach is presented to fabricate in situ integrated TFSs with a core-shell structure on alloy components using coaxial multi-ink printing technique.This method replaces traditional layerby-layer(LbL) deposition and LbL sintering processes and achieves simplified one-step manufacturing.The coaxial TFS includes a conductive Pt core for conducting and sensing and a dielectric shell for electrical isolation and high-temperature protection.The coaxial Pt resistance grid demonstrates excellent high-temperature stability,with a resistance drift rate of only 0.08%·h^(-1) at 800 ℃,significantly lower than traditional Pt TFSs.By employing this method,a Pt thin-film strain gauge(TFSG) is fabricated that boasts remarkable high-temperature electromechanical properties.This effectively addresses the problem of sensitivity degradation experienced by traditional LbL Pt TFSGs when subjected to high temperatures.We demonstrate the system integration potential of the technique by printing and verifying the functionality of a long-path thinfilm resistance grid on turbine blades,which can withstand butane flame up to ~1300℃.These results showcase the potential of core-shell structure of the coaxial TFS for high-temperature applications,providing a novel approach to develop high-performance TFS beyond traditional multilayer structure.

毫米波多内导体布喇格结构电磁特性研究

基于多模耦合理论,利用三维电磁仿真软件CST对毫米波双内导体和三内导体布喇格结构电磁特性分别进行了比较研究。结果表明:双内导体布喇格结构相比同轴布喇格结构可以抑制竞争模式,反射率稳定并接近1,对称性结构电磁特性优于非对称性结构;随着内导体距离同轴轴心距离的增大,双内导体布喇格结构频率响应带宽变宽,且当内导体距离同轴轴心距离较远时,带宽变宽趋势明显,而反射率值趋于稳定;对于三内导体布喇格结构,随着内导体距离同轴轴心距离的增大,频率响应带宽变窄,且当内导体距离同轴轴心距离较近时,带宽变宽趋势明显。因此,可根据实际需要恰当选择毫米波多内导体布喇格结构参数,拓宽其作为反射器或者滤波器的性能,提高模式的选择性及模式的纯度,改善布喇格结构的性能。

液态金属堆内小长径比同轴双层薄壁结构的流固耦合试验研究

池式液态金属堆的主容器与热屏之间具有狭窄的流体间隙,该结构属于含窄缝间隙的小长径比同轴双层柔性壳体。窄缝间隙中流体与结构之间相互作用产生的流固耦合效应在抗震分析时必须加以考虑。现有研究主要针对长径比较大和流体间隙相对较大的圆柱壳体,对于小长径比和极小流体间隙的同轴柔性壳体研究较为缺乏。本文参考液态金属反应堆的结构设计了三种不同尺寸的窄缝间隙,开展窄缝间隙条件小长径比同轴双层壳体模型的振动试验,测量结构在不同间隙尺寸下的加速度,得到模态频率和主要振型。然后,使用有限元法进行模态分析,通过与试验结果的对比,验证了有限元法的准确性。最后,计算出不同间隙尺寸下模型的附加质量;且随着间隙尺寸的减小,模型附加质量随之增大。本研究可为类似的含窄缝小长径比同轴双层柔性壳体结构的抗震设计提供数据支持,对于液态金属堆的抗震分析具有重要意义。

同轴静电纺丝构筑微/纳米结构隔膜与电极材料用于锂离子电池:从原理到应用

锂离子电池因其高能量密度、长循环寿命、优异的倍率性能和热稳定性而备受青睐,成为从便携式电子产品到电动汽车等实际应用中的最佳电源。在这种背景下,同轴静电纺丝技术因可制造适用于锂离子电池的独特纳米纤维材料而备受关注。尤其纤维材料具有高比表面积、高孔隙率、较大的长径比和易表面改性的优点,近年来在锂离子电池领域被广泛研究。这篇综述全面总结了同轴静电纺丝的基本原理、正极、负极和隔膜等锂离子电池关键材料的制备、实际应用和最新进展,并讨论了同轴静电纺纤维材料的纳米/微米结构决定其电化学性能的规律。此外,该综述分析了同轴静电纺丝未来的发展方向,强调了未来拓展同轴静电纺丝技术在锂离子电池领域的应用所面临的挑战。

优化嗜酸乳杆菌JYLA-191抗逆性方法研究

为了提升益生菌的抗逆性,以明胶/果胶/海藻酸钠复合物为壁材,油凝胶为载体,采用同轴滴注法制备具有核壳结构的嗜酸乳杆菌JYLA-191滴丸,并对其形态和菌株在加工、储存、热处理和消化过程中的稳定性进行评价。结果表明,双层滴丸有着明显的核壳结构且菌株均匀分布在内层油凝胶中。经加工双层滴丸活菌数降低了1.02 lg(CFU/g),较单层滴丸活菌数降幅低0.89 lg(CFU/g)。2种滴丸均能通过上消化道并在结肠中释放。单层和双层滴丸经连续消化后活菌数分别达到6.38 lg(CFU/g)和8.43 lg(CFU/g)。与单层滴丸相比,双层滴丸中的嗜酸乳杆菌JYLA-191在胆盐溶液中展现出更好的抗性,细胞活性没有明显的损失(P>0.05)。单层和双层滴丸均提升了嗜酸乳杆菌JYLA-191的耐热性,且双层滴丸经70℃热处理,细胞活性仍能达到5.39 lg(CFU/g)。2种滴丸在4℃和25℃下储存均提升了细胞的稳定性,其中4℃下储存效果更好。较单层滴丸,双层滴丸包埋的嗜酸乳杆菌JYLA-191稳定性更高。结论:双层滴丸有效了提升嗜酸乳杆菌JYLA-191在恶劣环境下的抗逆性。

基于同轴聚焦微流控拓扑构造的双乳液滴生成机制数值模拟

采用流体体积(VOF)相界面追踪技术建立了同轴聚焦微通道内双乳液滴生成过程的数值计算模型。当内相、中间相和外相流体流速分别为0.01、0.011、0.04m/s时,该模型能够稳定形成单分散性较好、直径为500μm的双乳液滴。形成的双乳液滴适合药物领域的应用。在此基础上,分析了聚焦孔半径、聚焦孔颈长与聚焦孔颈角对三相流体的液滴驱动方式的影响,并讨论了微流道拓扑结构变化与双乳液滴生成机制及特性的内在联系与机理。结果表明,聚焦孔半径影响了Marangoni效应对内液滴局部扰动的程度,在改变生成液滴截面尺寸的同时,也使液滴生成频率发生相应的变化。聚焦孔颈长的改变决定了内外相流体的流型,限制了液膜断裂与脱离过程,从而对液滴生成方式产生根本性影响。聚焦孔颈角的变化影响了鞘液对外界面的剪切作用,通常情况下较大的角度使得局部流体阻力得以缓慢的释放,有利于生成液滴界面的稳定性。

一种基于矩形同轴结构的微波大气压等离子体射流装置

微波大气压等离子体射流具有密度大、电离度高及粒子活性强等优点,在材料处理和医疗等领域受到了广泛关注,但现有微波大气压等离子体射流源还存在射流及单次处理面积小、均匀性有限等问题。基于矩形同轴结构设计了一款工作在2.45 GHz的便携微波大气压等离子体射流源,优化设计了馈电点位置参数,分析了内外导体间隙对间隙电场强度的影响,探究了不同氩气气体流速对等离子体形貌的影响。研究结果表明,随气体流量增加等离子体形貌发生变化,在气流为40 L/min时产生宽约20 mm,长约3 mm的等离子体射流。该装置的提出一定程度上解决了工业应用中的等离子体源均匀性和处理面积不足的问题,也有助于大面积均匀等离子体的进一步深入研究。

基于同轴柯勒照明的大变倍比紧凑型显微镜设计

为了实现大靶面、大变倍比显微成像并解决同轴柯勒照明高集成度设计的问题,本文提出了一种基于同轴柯勒照明的大变倍比紧凑型显微镜光学系统设计方法。首先,对望远镜和显微镜连续变倍光学系统的成像原理进行了分析,并对正组补偿式变倍显微镜光学系统的设计原理进行了理论分析。然后,提出把前固定组分解为准直组和汇聚组,并在两镜组间设计分光镜,并通过共用透镜组实现同轴柯勒照明系统的紧凑型设计。最后,对大靶面连续变倍显微镜系统和与之匹配的同轴柯勒照明光学系统进行设计,设计结果表明显微成像光学系统的变倍比为10×,工作距离为60 mm,物方最高分辨率为1.75µm,同轴照明均匀性为94.3%。该系统具有成像质量好、畸变小、变倍曲线平滑、体积小巧等特点,实验验证了该设计方法的可行性。

载木犀草素纳米纤维膜的制备与性能

采用2种pH敏感材料(Eudragit S100和Eudragit RS100),通过同轴静电纺丝技术制备了壳/核结构载木犀草素纳米纤维膜,通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、傅里叶变换红外光谱仪(FTIR)、X射线衍射仪(XRD)等研究了壳/核结构载木犀草素纳米纤维膜的表面形貌、化学结构和药物释放性能。结果表明:壳/核结构载木犀草素纳米纤维膜表面整体较光滑,纳米纤维平均直径随木犀草素含量增加而增大。该纳米纤维膜具有良好的结肠靶向性和生物相容性。

Design and manufacture of a 100 kA coaxial pulsed power cable for plasma generator and PPS in ETC guns

Based on our previous pulsed current and internal overvoltage test data and the experience of common commercial high power cables,a 100 kA coaxial pulsed power cable is designed and manufactured to adapt the coaxial electric energy breech transmission between the plasma generator and the pulsed power supply(PPS) in electrothermal-chemical(ETC) guns.The index parameters are analyzed and determined.Semi-conductor layers and a shield stiffener are introduced to prevent the deformation and burst of the pulsed power cable structurally.The semi-conductor layer can eliminate the air gap and balance the electric field in the cable.The shield stiffener can multiply the mechanical strength to restrain the strong electrodynamic force produced by the core dislocation of the outer conductor.The multi-coupling of electromagnetic field,stress field and thermal field analysis are established to assist in aided design of electrical strength,mechanical strength and temperature rise characteristics.Both a DC voltage withstand test and pulsed discharge tests are introduced to verify and inspect the performance and dynamic response of the pulsed power cable.The 25 kV/5 min DC voltage withstand test result shows that the sample leakage current is nearly 3 μA and no abnormal phenomena of the pulsed power cable sample occurred.The pulsed discharge tests show that the sample can sustain the 100 kA peak current.Furthermore,this 100 kA coaxial pulsed power cable can satisfy the ETC test requirements.

Continuous Fabrication of Ti_(3)C_(2)T_x MXene-Based Braided Coaxial Zinc-Ion Hybrid Supercapacitors with Improved Performance

Zinc-ion hybrid fiber supercapacitors(FSCs)are promising energy storages for wearable electronics owing to their high energy density,good flexibility,and weavability.However,it is still a critical challenge to optimize the structure of the designed FSC to improve energy density and realize the continuous fabrication of super-long FSCs.Herein,we propose a braided coaxial zinc-ion hybrid FSC with several meters of Ti_(3)C_(2)T_x MXene cathode as core electrodes,and shell zinc fiber anode was braided on the surface of the Ti_(3)C_(2)T_x MXene fibers across the solid electrolytes.According to the simulated results using ANSYS Maxwell software,the braided structures revealed a higher capacitance compared to the spring-like structures.The resulting FSCs exhibited a high areal capacitance of 214 mF cm^(-2),the energy density of 42.8μWh cm^(-2)at 5 mV s^(-1),and excellent cycling stability with 83.58%capacity retention after 5000 cycles.The coaxial FSC was tied several kinds of knots,proving a shape-controllable fiber energy storage.Furthermore,the knitted FSC showed superior stability and weavability,which can be woven into watch belts or embedded into textiles to power smart watches and LED arrays for a few days.

Atomic Modulation of 3D Conductive Frameworks Boost Performance of MnO2 for Coaxial Fiber‑Shaped Supercapacitors

Coaxial fiber-shaped supercapacitors are a promising class of energy storage devices requiring high performance for flexible and miniature electronic devices.Yet,they are still struggling from inferior energy density,which comes from the limited choices in materials and structure used.Here,Zn-doped CuO nanowires were designed as 3D framework for aligned distributing high mass loading of MnO2 nanosheets.Zn could be introduced into the CuO crystal lattice to tune the covalency character and thus improve charge transport.The Zn–CuO@MnO2 as positive electrode obtained superior performance without sacrificing its areal and gravimetric capacitances with the increasing of mass loading of MnO2 due to 3D Zn–CuO framework enabling efficient electron transport.A novel category of free-standing asymmetric coaxial fiber-shaped supercapacitor based on Zn0.11CuO@MnO2 core electrode possesses superior specific capacitance and enhanced cell potential window.This asymmetric coaxial structure provides superior performance including higher capacity and better stability under deformation because of sufficient contact between the electrodes and electrolyte.Based on these advantages,the as-prepared asymmetric coaxial fiber-shaped supercapacitor exhibits a high specific capacitance of 296.6 mF cm^−2 and energy density of 133.47μWh cm^−2.In addition,its capacitance retention reaches 76.57%after bending 10,000 times,which demonstrates as-prepared device’s excellent flexibility and long-term cycling stability.

Analysis of the Agglomeration of Powder in a Coaxial Powder Feeding Nozzle Used for Laser Energy Deposition

To improve the agglomeration of powder in a coaxial powder feeding nozzle used in the frame of a laser energy deposition technique,the influence of several parameters must be carefully assessed.In the present study the problem is addressed by means of numerical simulations based on a DEM-CFD(Discrete Element Method and Discrete Element Method)coupled model.The influence of the powder flow concentration,powder flow focal length and the amount of powder at the nozzle outlet on the rate of convergence of the powder flow is considered.The role played by the nozzle outlet width,the angle between the inner and outer walls and the powder incident angle in determining the powder flow concentration is also considered.The results show that,with increasing of nozzle outlet width,the powder flow concentration per unit volume at the nozzle focal point undergoes a non-monotonic behaviour(it first increases and then decreases).When the nozzle outlet widthδis 1.00 mm,the powder flow concentration at the focal point is maximal and the powder flow convergence can be considered optimal.By increasing the angle between the inner and outer walls,the powder flow concentration related to the upper focus decreases,the focus diameter increases and the powder flow aggregation worsens.The powder flow concentration increases first and then decreases with increasing incident angle.When the incident angleθis 30°,the powder flow exhibits the best agglomeration properties.When the outlet width is smaller,the angle between the inner and outer walls is larger,and when the incident angle is set at 30°,the powder flow concentration of the coaxial nozzle can be effectively improved.

基于光线追迹非同轴激光雷达重叠因子影响因素的分析研究

重叠因子是影响激光雷达系统探测近距离大气的一个关键因素,对其进行精确计算有利于获得更准确的探测结果.为此,提出了一种通过光线追迹获得非同轴激光雷达系统重叠因子的仿真方法.该方法利用ZEMAX分别对载入真实机械结构的发射系统和望远镜接收系统进行光线追迹,确定出同一距离处激光强度分布和望远镜的视场函数分布,通过计算重叠区域被望远镜视场函数加权后的激光强度占激光总强度的比例,可得到该距离处的重叠因子,最后通过不同距离处的重叠因子拟合出完整的重叠因子廓线.此外,利用此方法对一套激光雷达系统进行了几何因子廓线仿真,并分析了系统轴间距、光轴失调角度、激光发散角、望远镜视场角以及次镜机械遮挡对系统重叠因子廓线的影响.仿真结果表明当激光光轴偏离望远镜光轴的角度等于望远镜视场角和激光发散角差值的1/2时,远场的重叠因子不能达到1,这对激光雷达系统的设计和安装提出了更高的要求.

Dispersion Equation of the Coaxial-Radial Line

An all-metal slow-wave structure, coaxial-radial line, which is suitable for application in broadband high power traveling wave tube (TWT) and relativistic TWT as a RF system is introduced. Making use of the field matching method and variational method together with the orthogonality of the Bessel function and the Floquet Theroem for the periodic system, the dispersion characteristic expression is derived. This equation is more rigorous than that of precious reports.

甲烷/富氧空气同轴喷嘴燃烧性能研究

燃烧型空气加热器是开展地面试验时模拟高空来流的重要设备,一般采用同轴喷注燃烧方式。为满足设计总温1200 K的甲烷空气加热器正常运行的要求,本文开展了单元同轴喷嘴点火/稳焰的研究,分析了氧浓度、喷嘴构型对燃烧稳定性和燃烧效率的影响,并结合数值模拟获得燃烧室温度分布以及流场结构,对比甲烷/富氧空气与甲烷/氧气燃烧特性的异同。研究结果表明:直口型喷嘴出口壁厚较大,产生更大的稳焰回流区,为甲烷燃烧提供持续稳定的点火源,燃烧效率最高为99.98%;氧浓度对燃烧稳定性影响较大,随着氧浓度的降低,燃烧稳定性下降,当氧浓度低于39%时,燃烧室内不能形成稳定的火焰;甲烷/富氧空气燃烧依靠喷嘴出口回流区稳定火焰,喷嘴构型不会影响火焰稳定位置。

赛络纺棉/毛段彩纱结构及其性能

针对环锭纺三罗拉和四罗拉法所纺段彩纱条干不匀的结果问题,采用同轴双后罗拉2组粗纱同锭位藕合等量喂入的方法纺制等线密度赛络纺棉/毛段彩纱,并对成纱的结构及性能进行了分析。纱线的纵向观测结果表明棉与毛的质量比差异越大,分段时间越长,纱线的段彩效果越明显;截面观测结果表明棉和毛纤维在纱中互相压紧并包缠形成类似于太极阴阳鱼的结构;分段中棉与毛质量比差异及纺纱分段时间增加时,纱线的断裂强度变小,CV值变大,但对有害毛羽数量影响不大。该纺纱方法使用天然的棉和毛纤维,既丰富了现有花式纱线的产品种类,也在对细纱机进行简单改装的条件下制得股线风格的毛型感段彩纱,符合绿色低碳循环发展的趋势。