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101.
等截面梁有限变形的传递函数解法 总被引：2，自引：0，他引：2
本文应用传递函数方法对等截面梁的有限变形进行了分析,对于等截面梁的有限变形问题,该方法从变分方程出发把问题表述为状态空间的形式,然后利用Gauss积分对轴力进行加速迭代求解,不需要进行增量迭代即可取得具有良好计算精度的数值结果,对简单受力的等截面梁情况该解可以看作是所讨论问题的精确解。对于受力比较复杂或者阶梯变截面梁情况,为减少运算量,可以和有限元法类似,采用多个单元进行拼接,从而得到问题的解。数值算例表明,本方法具有半解析、精度高、收敛快等特点。 相似文献
102.
103.
LIU Qingmin;HOU Shanglin;LEI Jingli 《光子学报》2022,51(9):207-216
Surface Plasmon Resonance （SPR） is a prominent optical phenomenon that arises as the extent of energy transferring from photons to surface plasmon waves under appropriate conditions. In the past few years, this optical effect, owing to its high sensitivity, real-time detection, and anti-interference has already been extensively investigated and applied in medical treatment, environment monitoring, biomedical sensing and so on. Based on the principle of SPR, a novel D-shaped gold surface plasmon resonance photonic crystal fiber with one open-ring is proposed for detecting low refractive index materials has been investigated in detail. The proposed photonic crystal fiber of the simulation model is composed of three layers of air holes. The radii of air holes in the first-layer and third-layer are r 1 and r 3, respectively. While the second-layer air ring consists of air holes with two different radii, r 2 and r s. The refractive index of air is fixed at n air = 1 and the radius of the cladding is R . A thin gold film with thickness t g is deposited on the inner surface of the micro-opening analyte channel on the upper side, the radius and the central location of the channel are r s and 2.5×Λ -1.25×r s, respectively. The fiber material is fused silica and the RI is determined by the Sellmeier equation, the relative dielectric constant of gold can be demonstrated by the Drude-Lorentz model. This paper uses the finite element method and sets the boundary conditions of the perfect matching layer for simulation. In order to investigate how the sensing performance of the proposed PCF-SPR sensor is affected by the parameters of the optical fiber, the effect of various parameters of the fiber such as air radii （r 1, r 2, r 3, r s）, air hole spacing （Λ ） and the gold film （t g） on the SPR loss spectrum have been studied separately. The simulation results show that the confinement loss decreases as r 1 increases. This can be attributed to the fact that more energy is confined to the core when r 1 increases, which affects the coupling between the core and plasmonic modes. At the same time, the confinement loss also decreases with the increase of r 2, and the corresponding blue shift occurs with the resonance peaks moving toward a shorter wavelength over the process. The reason is that the increase of r 2 will increase the refractive index difference between the plasmonic mode and core mode, which will affect the coupling between them. Therefore, with the increase of r 2, the shorter wavelength can excite the plasmonic mode, resulting in the phenomenon of wavelength blue shift in the loss spectrum. Since the air holes of the third layer are located at the outermost part of the fiber, the change of r 3 has little impact on the confinement loss, which can greatly reduce fabrication difficulty of the sensor. The pitches between the air holes are also an important factor in confinement loss, the change of Λ will influence the refractive index of core mode and plasmonic mode, which in turn affects the phase matching condition and energy coupling between them. The thickness of gold film plays a vital role in the sensing performance. If the gold film is too thick, the electric field can not penetrate the gold film, which will reduce the sensitivity of the proposed sensor. While if the gold film is too thin, the plasmonic wave will be strongly suppressed due to radiation damping. Therefore, the thickness of gold film can significantly affect the coupling between the core mode and the plasmonic mode. After optimizing the various parameters affecting the sensing performance of the sensor, we analyse the analytes with different refractive indices. Simulation results show that the sensor operates in the near-infrared and mid-infrared region with the wavelength range of 2 020~3 036 nm in the refractive index range of the analyte of 1.18~1.30. When the refractive index of the analyte is in the range of 1.23 to 1.30, the sensor operates in the band of 2 135~3 036 nm, and the average value of spectral sensitivity is up to 11 650 nm/RIU. When the refractive index of the analyte is between 1.29 and 1.30, the sensor operates in the mid-infrared band of 2 648~3 036 nm, and the maximum spectral sensitivity and resolution are 38 800 nm/RIU and 2.37×10-6 RIU, respectively. The proposed sensor shows great significance in detecting low refractive indexes in near- and mid-infrared waveband, and has potential applications in biomedical sensing, water environment and humidity detection and so on. 相似文献
104.
YANG Yi;LEI Jiayuan;WANG Xiaobo;HE Fengtao;LIU Yan;NIE Huan 《光子学报》2022,51(10):195-207
Considering the competition for oceanic resources among different nations, Underwater Wireless Communication （UWC） technology has a lot of potential for development. As compared to its traditional counterparts, namely underwater acoustic communication and radio frequency communication, Underwater Wireless Optical Communication （UWOC） has many advantages, such as a strong information-carrying capacity, a faster communication rate, and good confidentiality, which can better suit the practical communication requirements of high-speed and large-capacity, lower implementation costs, and lower time latency in underwater wireless communication. The effects of the UWOC channel on the received laser pulse are typically categorized into the signal power attenuation caused by absorption, scattering, and the light intensity scintillation caused by oceanic turbulence, which leads to a decline in the transmission performance （bit error rate） of the UWOC system. The most widely used turbulence channel models are only suitable for a specific turbulence state. In order to further analyze the signal characteristics and system performance of the UWOC system of the Offset Quadrature Phase Shift Keying （OQPSK） modulation under the common action of turbulence channel and attenuation channel, this paper uses the Exponential Generalized Gamma （EGG） turbulence distribution model, which is more consistent with real oceanic channel characteristics. We obtain the turbulent random noises utilizing the acceptance-rejection sampling algorithm and further establish a composite channel model taking into account the attenuation channel, turbulence channel, and the Additive White Gaussian Noise （AWGN）. In addition, according to the waveform of simulating signal, varying turbulence noise parameters, system noise parameters, and attenuation channel parameters, we analyze the average Bit Error Rate （BER） characteristics of the OQPSK modulation in the UWOC system. The simulation results show that the signal waveform does not change when it passes through the attenuation channel, but the amplitude is severely attenuated; the signal envelope passing through the turbulence channel changes with time, and the speed of signal amplitude change is negatively correlated with the turbulence coherence time; the signal waveform passing through the composite channel is distorted nonlinearly. For strong oceanic turbulence of the scintillation index ![]()
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105.
应力发光是某些材料受到机械刺激时产生的发光现象。许多固体材料在压裂过程中会产生应力发光,但这种破坏性发光限制了材料的实际应用。可再生应力发光的发现为应力发光材料创造了解决现实问题的机会,其在结构健康诊断、力驱动的新型光源和显示器件以及生物力学应力传感器等领域展现出广泛的应用前景。本文对近二十年来无机可再生应力发光材料的研究进展进行了梳理和总结,主要介绍无机可再生应力发光材料的分类、表征、机理和应用四个方面,并讨论了未来研究中所面临的机遇和挑战,以期对该类材料的研发及应用提供有意义的启示。 相似文献
106.
敞开式离子化质谱(Ambientionizationmassspectrometry,AI-MS)是近年来兴起的质谱分析技术,可在敞开的大气环境下实现离子化,无需或只需少许样品前处理步骤,具有实时、简便、快速、高通量等诸多优点。近年来AI-MS技术的发展与应用已成为质谱领域备受关注的热点之一。该文综述了AI-MS的技术分类与原理特点,总结了AI-MS在微生物领域的应用。重点介绍了AI-MS在微生物种属鉴定与分型、微生物代谢物分析与生物膜分析、质谱成像等领域的应用。目前,环境电离与便携式质谱仪相结合已得到越来越广泛的应用,即将成为质谱领域的新热点。 相似文献
107.
针对保健食品中西地那非药物的非法添加问题,该研究采用辣根过氧化物酶（HRP）与鲁米诺为信号输出系统,结合直接竞争模式探索了保健食品中西地那非的直接竞争化学发光酶免疫分析方法。基于特异性多克隆抗体,通过逐步优化策略,确定最佳免疫分析条件为：包被原质量浓度为41.67ng/mL,酶标抗体质量浓度为1.25μg/mL,封闭液和洗涤液的吐温－20含量为0.05%,稀释液的甲醇添加量为5%,竞争反应时间为40min。在该条件下,建立了西地那非的直接竞争化学发光免疫分析方法,该方法对西地那非的半抑制浓度（IC50）为0.17ng/mL,线性检测范围（IC20～IC80）为0.024~1.21ng/mL,检出限（IC10,LOD）为0.008ng/mL。与他达那非等功能类似物无显著交叉;西地那非样品的加标回收率为82.0%～114%,相对标准偏差均小于15%。盲样检测结果与HPLC－MS/MS确证方法具有良好一致性,说明该方法准确可靠,适用于样品中西地那非的快速筛查。 相似文献
108.
纸基微流控技术（μPADs）是一种在微米尺度的纸基芯片上进行样品制备、反应、分离、检测的技术,具有材料便宜、制作简单、易回收、结构多样、试剂消耗少、环保可降解等特点,在食品安全快速检测领域具有实用价值。该文对纸芯片制备、流体操控及检测模式进行了介绍。首先阐述了纸芯片功能化改性方法及生物分子的固定方式,总结了经处理后的纸张制备为二维（2D）或三维（3D）纸芯片的方法;其次论述了流体在纸基材料上不完全浸湿和完全浸湿两个阶段的运输机理,综合分析了智能化流体操纵技术;最后介绍了可与纸基微流控平台联用的检测方法,并综述了纸基微流控装置在食品安全检测中的应用研究进展,提出纸基微流控技术在食品行业未来面临的挑战及发展趋势。 相似文献
109.
王晓丽;简瑛瑛;雷晶晶;张子灏;王军利;吴巍炜 《光子学报》2021,50(10):1014004
使用一种新型有机材料马来酸掺杂聚苯胺作为可饱和吸收体,在掺铒全光纤激光振荡器中实现稳定的调Q运转。实验中,采用双臂探测法测得该材料的调制深度和可饱和吸收强度分别为13.9%和0.336MW/cm2,将其以薄膜三明治形式插入到光纤谐振腔中,最终获得了重复频率从33.78kHz到87.01kHz的范围内可调,最窄脉冲宽度为2.29μs,最大单脉冲能量为54.64nJ的稳定调Q脉冲输出。马来酸掺杂聚苯胺可以被认为是脉冲光纤激光器应用及其它光电器件的良好候选者。 相似文献
110.