Monitoring the hydrolyzation of aspirin during the dissolution testing for aspirin delayed-release tablets with a fiber-optic dissolution system

The purpose of this study was to investigate the hydrolyzation of aspirin during the process of dissolution testing for aspirin delayed-release tablets. Hydrolysis product of salicylic acid can result in adverse effects and affect the determination of dissolution rate assaying. In this study, the technique of differential spectra was employed, which made it possible to monitor the dissolution testing in situ. The results showed that the hydrolyzation of aspirin made the percentage of salicylic acid exceed the limit of free salicylic acid （4.0）, and the hydrolyzation may affect the quality detection of aspirin delayed-release tablets.

Application Research of the Non-Destructive Testing Using Optical Fiber Sensor

In this paper, an optical fiber sensor is designed by using optical Faraday effect. It is composed of fiber collimator, polarizer, magneto-optical crystal and mirror. Based on the magnetic flux leakage (MFL) theory, The optical fiber sensor was placed between two permanent magnets with the N-pole. Therefore, the optical fiber sensing system was built to detect the defective ferromagnetic objects. Theoretical and experimental studies shown that the system can identify a little defects, such as irons’ blind hole (diameter φ =?3mm , depth t = 4mm?), irons’ grooves (length l= 30mm , width?ω = 10mm ), hole (φ?=?3mm ) and crackle etc. The system has the characteristics of small size, high sensitivity, fast signal response and high resolution. In terms of the defective oil and gas pipelines detection, The optical fiber sensing system is used in non-destructive testing, which will be valuable and meaningful.

文献《Validation of commercial fiber optic components for aerospace environments》点评

文章是对一篇SPIE会议文献《用于太空环境的商业光纤器件地面验证方法》的点评。介绍了商业光纤部件从市场采购到准备作为太空飞行部件使用前,在空间环境作用(包括真空、热、振动、辐射)下的地面工艺性合格鉴定试验技术。这项技术由NASA哥达德空间飞行中心(GSFC)创立并命名为"工艺技术有效性保证法",该项技术还包括如何建立商用光纤产品制造工艺性合格鉴定试验验收标准或准则方面的内容。"点评"还针对文献中3个实例之一"水星激光高度仪"试验件的热与振动环境试验规范、试验夹具等重要试验技术信息进行详细介绍。

Distributed Fiber Optic Monitoring and Stability Analysis of a Model Slope under Surcharge Loading

In the discipline of geotechnical engineering, fiber optic sensor based distributed monitoring has played an increasingly important role over the past few decades. Compared with conventional sensors, fiber optic sensors have a variety of exclusive advantages, such as smaller size, higher precision, and better corrosion resistance. These innovative monitoring technologies have been successfully applied for performance monitoring of geo-structures and early warning of potential geo- hazards around the world. In order to investigate their ability to monitor slope stability problems, a medium-sized model of soil nailed slope has been constructed in laboratory. The fully distributed Brillouin optical time-domain analysis （BOTDA） sensing technology was employed to measure the horizontal strain distributions inside the model slope. During model construction, a specially designed strain sensing fiber was buried in the soil mass. Afterward, the surcharge loading was applied on the slope crest in stages using hydraulic jacks and a reaction frame. During testing, an NBX-6o5o BOTDA sensing interrogator was used to collect the fiber optic sensing data. The test results have been analyzed in detail, which shows that the fiber optic sensors can capture the progressive deformation and failure pattern of the model slope. The limit equilibrium analyses were also conducted to obtain the factors ofsafety of the slope under different surface loadings. It is found that the characteristic maximum strains can reflect the stability of the model slope and an empirical relationship was obtained, This study verified the effectiveness of the distributed BOTDA sensing technology in performance monitoring of slope.

Stress test and analysis based on SMS fiber structure with high sensitivity

Single mode-multimode-single mode （SMS） sensor is widely used for parameters measurement, such as bending, dis-placement, temperature, strain, refractive index, etc. Generally, SMS sensor has advantages of simple structure, low cost and easy layout, therefore it has become a research hotspot in recent years. In this paper, the multimode fiber with large core is used for manufacturing SMS structure with high sensitivity. Firstly, the multimode fiber with core/cladding diameters of 105/ 125 jitm has access to the system by means of single mode optical fiber. Secondly, SMS device structure is manufactured by welding the eccentric shaft of multimode optical fiber. Afterwards, mode interference effect and spectral response characteristics of the structure of single mode-multimode-single mode optical fiber are analyzed theoretically. Finally, with the help of a wide spectrum light source and a spectrum analyzer, the transmission spectra characteristics of SMS optical fiber with strain is tested. By observing the curve that the wave changes with stress, the sensitivity is calculated and it is consistent with theoretical value .

A hardening load transfer function for rock bolts and its calibration using distributed fiber optic sensing

Confinement of rock bolts by the surrounding rock formation has long been recognized as a positive contributor to the pull-out behavior,yet only a few experimental works and analytical models have been reported,most of which are based on the global rock bolt response evaluated in pull-out tests.This paper presents a laboratory experimental setup aiming to capture the rock formation effect,while using distributed fiber optic sensing to quantify the effect of the confinement and the reinforcement pull-out behavior on a more local level.It is shown that the behavior along the sample itself varies,with certain points exhibiting stress drops with crack formation.Some edge effects related to the kinematic freedom of the grout to dilate are also observed.Regardless,it was found that the mid-level response is quite similar to the average response along the sample.The ability to characterize the variation of the response along the sample is one of the many advantages high-resolution fiber optic sensing allows in such investigations.The paper also offers a plasticity-based hardening load transfer function,representing a"slice"of the anchor.The paper describes in detail the development of the model and the calibration/determination of its parameters.The suggested model captures well the coupled behavior in which the pull-out process leads to an increase in the confining stress due to dilative behavior.

Novel manufacturing method of optical fiber coupler

Based on the coupling mode theory that the coupling ratio of fiber coupler changes periodically with center distance of two optical fibers, a novel manufacturing method of optical fiber couplers was developed with fused biconical taper experimental system. Its fabrication process is that the fiber is fused but not stretched when light begins to split, and the reduction of diameter of fiber is dependent on the theological characteristic of the fused fiberglass. The performance of the coupler was tested. The results show that the performance of the novel optical fiber coupler meets the performance expectations, and its diameter of coupling region （about 30 μm） is twice as long as that of classical fused biconical taper coupler （about 16 μm）, so the default, that is, the device is easy to fracture, is restrained and the reliability is greatly improved.

Zemax-Based Optimum Structural Design of Probe of an Optical-Fiber Sensor

Bubble plumes are important during the process of air-sea exchange,and optical-fiber phase detection is a suitable way to observe bubble plumes entrained by breaking waves.This paper designs a new optical-fiber probe(OFP)made of sapphire to overcome the limitations of existing materials(e.g.,high brittleness,poor corrosion resistance,and narrow bandwidth)and thereby enhance the detection performance of the OFP by improving its structure.Based on total internal reflection and light refraction,a simulation model of the probe is established in the Zemax optical design software to optimize the probe tip and matching mode of the two probe tips.The results show that the optimum OFP tip is a conical sapphire one with a cone angle of 35°.Tests are then conducted on a bespoke OFP sensor,the results of which are consistent with those predicted theoretically.The simulation results lay the foundation for the integrated design of OFP sensors and the optimization of their internal optics.The findings could also be applied to OFPs with multiple tips.

Debonding Patch Detection in FRP-Strengthened Materials with Fiber-Optic Interferometer

The interfacial debonding in fiber-reinforced plastic(FRP)strengthened repair material will affect the bonding strength and lead to failure of the repair without warning.Unfortunately the interfacial damage is normally invisible and often in the form of a patch rather than a through-width crack.Therefore,a debonding patch detection technique based on fiber optic interferometry is proposed.A quasi-impulse loading is applied with a rubberhead hammer and the total elongation of a surface-mounted optical fiber along the length of the repair material is measured as a function of load position.When a debonding patch is present,the induced sudden slope or sign change on the plot of fiber integral strain v.s.load position will reveal the extent and the location of the debonded area.The results of the study indicate that the proposed technique is applicable for debonding patch detection in repaired members under various support conditions.

Dynamic Temperature Characteristics of Liquid Filled Photonic Crystal Fiber

The dynamic characteristics of high sensitivity temperature sensor are studied by using siphon method to fill the air hole near the core of the hollow photonic crystal fiber with Cargille matching liquid,and the two ends are fused with single-mode fiber in this work.We analyzed the working principle of filled photonic crystal fiber sensor by using the standard coupling mode theory of directional coupler.The coupling process was simulated by COMSOL software.When the photonic crystal fiber filled with 10 mm liquid was scanned by tunable laser,the temperature sensitivity was 7.50 nm /℃,the average temperature response time was 0.317 s,the average release time was 3.732 s,and the temperature variation linearity was 100%.The experimental results show that the liquid filled photonic crystal fiber has the advantages of high temperature sensitivity,fast response time and good linearity.

跨博-阿断裂隧道的抗错断性能模型试验

中国西部地区地质条件复杂,许多隧道工程在建设过程中会穿越不良地质区段,受到来自活动断层的错动威胁.为探究走滑断层作用下铰接隧道结构的应变响应规律及变形破坏机制,以天山胜利隧道工程为背景,利用光纤传感技术,通过室内缩尺模型试验,开展了走滑断层作用下分节段铰接隧道变形破坏研究.结果显示,隧道衬砌的变形主要发生在断层破碎带内部及边缘附近,隧道整体的破坏模式为拉压剪切组合破坏模式;沿隧道纵向,断层破碎带处隧道受力模式总体上为拱顶与拱底受拉,两侧既有受拉也有受压;沿截面环向,环向应变分布呈“W”形,存在两个拉应变峰值及两个压应变峰值,截面变形趋势为两侧受到水平挤压作用,迫使截面由马蹄形向椭圆形发展.研究结果揭示了走滑断层作用下铰接隧道的变形破坏形式以及衬砌变形规律,可为类似工程提供理论参考和技术支持.

鄂尔多斯盆地页岩油水力压裂试验场建设概述及实践认识

借鉴北美HFTS成功经验,长庆油田围绕进一步提高单井产量目标,整体规划了三期水力压裂试验场HFFL建设。I期于2022年启动,2024年完成,是国内首个完整意义上的水力压裂试验场。I期重点围绕夹层性页岩油长71、长72储层,坚持“压前地质工程一体化设计、压中测试响应反演拟合、压后取心验证分析评价”的研究路径,综合应用光纤、双井微地震、井下电视、示踪剂及取心等10项16井次测试,系统开展人工裂缝形态、多簇起裂及产液贡献率等精细评价,主要认识包括:(1)页岩油压后地下裂缝类型多样,300 m取心过程中累计发现裂缝431条,其中压裂缝115条、层理缝239条;(2)裂缝复杂程度远超预期,人工裂缝总量远大于簇数,局部未严格按照最大主应力方向扩展,受到岩性、天然裂缝发育等综合影响,裂缝存在明显偏转、沟通、弯曲等现象;(3)水力裂缝缝长延伸较长,缝高整体受控,支撑剂在取心岩屑中广泛分布,裂缝面同样观察到支撑;(4)多簇100%起裂,但扩展过程呈动态变化,砂液分配差异大,光纤评价均一指数平均61.8%;(5)长期产剖动态跟踪显示,生产6个月后,多裂缝段与优质甜点段贡献逐渐凸显。综上,水力试验场对长庆页岩油重新认识油藏、缝控储量、裂缝、产量提供了更加准确科学的理论依据,对井网优化、开发技术政策制定以及体积压裂优化设计都具有十分重要的作用,同时也为国内水力压裂试验场建设发挥了示范引领作用。

基于光纤感测的急倾斜煤层采动围岩变形特征研究

将分布式光纤传感技术应用于急倾斜煤层采场围岩变形及应力分布特征物理相似模型试验,通过在模型中沿煤层倾向布置传感光纤与沿煤层底板铺设压力传感器,实时监测模型内部变形场与应力场,并结合数值模拟分析了急倾斜煤层顶板应变分布及演化特征。结果表明:工作面上部区域应力值小于下部和中部区域,中部区域应力值最大;随工作面推进,采空区底板应力逐渐释放,应力值不断降低,采空区两侧边界煤柱下方煤层底板应力逐渐升高,且中、下部采空区底板应力恢复程度显著高于上部底板;沿煤层倾向布置的光纤应变曲线呈三段分布,具有前后2处应变波峰区及采空区对应的中部波谷区,前波峰远高于后波峰;工作面中上部顶板变形程度大于下部顶板;数值模拟与光纤检测结果一致,均表现出中上部顶板变形显著大于下部。研究弥补了物理相似模型试验监测手段短板。

基于温度循环加速退化试验的光纤连接器寿命评估

针对光纤连接器在温度交替变化下寿命评估难的问题,提出一种基于修正Coffin-Manson模型的寿命评估方法。首先,分析了光纤连接器失效模式、机理。接着,开展光纤连接器多个加速应力水平下的温度循环加速退化试验,基于插入损耗加速退化数据建立幂函数退化轨迹模型。然后,结合插入损耗的失效阈值,通过假设检验推导不同加速应力水平下光纤连接器的伪失效寿命。最后,引入修正Coffin-Manson加速模型,进而外推空间环境下光纤连接器寿命。本方法评估的某光纤连接器在实际应力水平下的寿命与实际寿命比较接近,验证了修正Coffin-Manson模型方法对光纤连接器寿命评估的有效性和可行性。

三边承载条件下预应力钢筒混凝土管承载能力的计算模型与试验验证

预应力钢筒混凝土管(PCCP)的承载能力计算涉及管芯开裂时的弯矩重分布,是管体结构设计的重要组成部分。本文针对现有计算方法中管芯开裂判定的经验性和现有试验结果中管芯开裂后管体变形的剧烈性问题,提出了三边承载试验下PCCP承载能力计算模型。模型基于刚性管假设推导了管壁截面的弯矩与轴力系数,采用简化的混凝土应力应变关系作为管芯开裂的判别标准,给出管芯开裂后的管腰处弯矩重分布和管顶(底)处轴力作用线移动的数学表达,开展了基于分布式光纤传感器测量的三边承载试验,并验证了计算方法的合理性。对比验证结果表明,管芯开裂前计算与试验结果基本一致,管芯开裂后计算与实测结果在趋势上相同。本文采用的计算模型与原型试验的对比分析框架,有助于更深入了解PCCP受载变形规律,并在未来用于管体设计参数的确定与优化。

无源多通道星载光纤滑环可靠性设计与试验

目前关于光纤滑环(FORJ)在空间应用领域的文献较少,设计了一种无源多通道星载FORJ,首先分析了该设备在空间环境中运行时可能面临的问题及挑战,然后基于成熟的技术方案进行了针对性的可靠性设计,最后对设计的星载FORJ进行了试验验证。试验结果表明,所提的无源多通道星载FORJ达到了空间应用要求。

穿舱光纤连接器密封性能分析及空间环境验证

穿舱光纤连接器的密封可靠性关系到载人航天器舱内气压的稳定,影响载人航天器的安全。为保证穿舱光纤连接器在空间应用环境复杂、在轨服役寿命长的工况中可靠应用,提出了一种穿舱光纤连接器高可靠双金锡光纤密封结构,并对光纤金属化焊接密封机理展开分析。基于航天器舱段连接应用泄漏率≤10^(-10 )(Pa·m^(3))/s、环境温度-100~100℃要求,对采用双金锡光纤密封结构的某型多芯穿舱光纤连接器进行了结构剖析,通过压力降级、温度缓冲、低应力结构等结构设计,保证了多芯穿舱光纤连接器的密封可靠性。开展了金属化光纤焊接密封工艺技术研究,通过焊料选取、CTE匹配性分析、二道密封工艺验证分析及小批量试制,验证了双金锡光纤密封结构设计及工艺技术的合理性和稳定性。试验验证表明,多芯穿舱光纤连接器在经历温度冲击、快速压降及高强度正弦振动等极限空间环境试验后,光学性能和密封泄漏率均合格,证明采用双金锡光纤密封技术的穿舱光纤连接器能够满足载人航天器长期在轨使用要求,并具有良好的使用可靠性。

基于光纤传感的带式输送机张力检测技术

针对目前带式输送机张力检测存在易损坏及准确性和可靠性差的问题,提出了一种基于光纤传感的带式输送机的张力检测方法。将法珀腔传感头置于带式输送机张紧装置的液压回路中,液压回路的压力使法珀腔传感头的硅膜片产生形变,引起法珀腔传感头反射光变化;光电解调器光路接收法珀腔传感头的反射光后,经光路解调后得到反射光谱,通过光电解调器电路的光电转换、处理、分析后,得到反射光光谱的自由光谱范围,再根据油缸内部面积计算出带式输送机张力,实现了带式输送机张力检测。根据双干涉效应原理设计了法珀腔传感头,采用Jetson Nano嵌入式系统开发板设计了光电解调器硬件,采用Python语言设计了光电解调器软件,并进行了实验研究。实验结果表明:该方法能够实现带式输送机张力检测,压力测量范围为0~25 MPa,灵敏度为0.148 nm/MPa,测量精度为0.1%,不易损坏,抗干扰性好,准确性和可靠性高。

基于BOTDA的砂土地基预应力管桩抗拔静载试验研究

针对砂土地基抗拔桩受力性能与荷载传递机理研究不足问题,将布里渊光时域分析(BOTDA)光纤传感技术应用于长江下游地区厚层砂土地基预应力管桩原位抗拔静载试验研究,采用特殊设计的桩身刻槽钻孔、光纤粘贴保护、接桩过程连续植纤等技术工艺,实现了预应力管桩在拉拔过程中桩身受力变形状态的分布式测量与数据精确定位。研究结果表明:在上拔荷载作用下,试验桩桩身轴力沿桩身方向逐渐减小;桩侧摩阻力在下桩发挥效果较好,上桩侧摩阻力较小,全桩长侧摩阻力最大值在桩底;抗拔桩随上拔荷载的增加,轴力逐渐向下传递,向下传递的轴力主要由预制管桩侧摩阻力承担;分布式光纤应变传感技术能较好地监测预应力管桩桩身贯入施工因素对抗拔承载特性的影响。研究结果可在其他类型抗拔桩受力特性监测项目中推广应用。

一种用于高压电气设备局放超声检测的新型EFPI传感器

文章介绍了一种新型结构的光纤EFPI超声传感器,可内置于变压器、GIS等高压电气设备,这种新型结构的光纤EFPI超声传感器可在不同温度、不同压强条件下,进行局部放电超声信号的检测。新型传感器采用全石英焊接工艺,在F-P腔上开孔,使绝缘介质进入F-P腔,平衡了石英膜片两侧由于温度和绝缘介质密度不同产生的压强差,并在石英膜片内表面上局部镀铝膜,提高膜片内表面的光反射率,提升了传感器的灵敏度。通过用新型传感器在不同温度、不同距离下进行测试,验证了传感器的温度、频率、灵敏度等性能。新型光纤EFPI超声传感器为检测高压电气设备内部局部放电提供了一种新的检测方法。实际应用中也取得了非常好的效果。