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Nowadays, early defect detection plays a significant role for the railway safety warning. However, the existing methods cannot satisfy the requirements of real-time and high-precision detection. Here, a high-precision, distributed and on-line method for detecting rail defect is proposed and demonstrated. When a train goes through defects, the instantaneous elastic waves will be excited by the wheel-rail interaction, which will further propagate along railway tracks bidirectionally. Through mounting the backscattering enhanced optical fiber on the railway as sensors, the fiber optic distributed acoustic sensing system can record the propagation trace precisely. Further, the acoustic propagation fitting method is applied onto the propagation data to detect and locate defects along the long-distance railway. Especially, the dual-frequency joint-processing algorithm is proposed to improve the location accuracy. The field test proves that multiple defects along the railway can be successfully identified and located with a standard deviation of 0.314m. To the best of our knowledge, this work is the first report of distributed rail defect detection, which will bring a breakthrough for high-precision structural damage detection in the infrastructures such as the railway, pipeline and tunnel.

In this Letter, we have proposed an in-fiber duplex optical antenna based on a 45° radiated titled fiber grating (RTFG), in which the 45° RTFG not only radiates the light from the fiber core to the free space, but also harvests the light from the free space back into the fiber core. Using the finite difference time domain method, we have theoretically analyzed the light recoupling efficiency of the RTFG. The simulated results have shown that the RTFG-based optical antennas have a maximum coupling efficiency of 10%. The recoupling wavelength and efficiency are related to the grating period and horizontal incidence angle. Furthermore, we demonstrate a programmable spectral filtering system based on the 45° RTFG antennas, which could achieve filtering with arbitrary spectral shapes. The spectral resolution is 0.4 nm and the insertion loss is around 20 dB. The proposed programmable spectral filtering system has a compact structure compared with the traditional filter.

Purpose The purpose of this paper is to propose a new approach to retrieve similar questions in online health communities to improve the efficiency of health information retrieval and sharing. Design/methodology/approach This paper proposes a hybrid approach to combining domain knowledge similarity and topic similarity to retrieve similar questions in online health communities. The domain knowledge similarity can evaluate the domain distance between different questions. And the topic similarity measures questions’ relationship base on the extracted latent topics. Findings The experiment results show that the proposed method outperforms the baseline methods. Originality/value This method conquers the problem of word mismatch and considers the named entities included in questions, which most of existing studies did not.

The accurate estimation and monitoring of phenology is necessary for modern agricultural industries. For crops with short phenology occurrence times, such as rice, Sentinel-1 can be used to effectively monitor the growth status in different phenology periods within a short time interval. Therefore, this study proposes a method to monitor rice phenology based on growth curve simulation by constructing a polarized growth index (PGI) and obtaining a polarized growth curve. A recursive neural network is used to realize the classification of phenology and use it as prior knowledge of rice phenology to divide and extract the phenological interval and date of rice in 2021. The experimental results show that the average accuracy of neural network phenological interval division reaches 93.5%, and the average error between the extracted and measured phenological date is 3.08 days, which proves the application potential of the method. This study will contribute to the technical development of planning, management and maintenance of renewable energy infrastructure related to phenology.

Optical fiber sensor network has attracted considerable research interests for geoscience applications. However, the sensor capacity and ultra-low frequency noise limits the sensing performance for geoscience data acquisition. To achieve a high-resolution and lager sensing capacity, a strain sensor network is proposed based on phase-sensitive optical time domain reflectometer (φ-OTDR) technology and special packaged fiber with scatter enhanced points (SEPs) array. Specifically, an extra identical fiber with SEPs array which is free of strain is used as the reference fiber, for compensating the ultra-low frequency noise in the φ-OTDR system induced by laser source frequency shift and environment temperature change. Moreover, a hysteresis operator based least square support vector machine (LS-SVM) model is introduced to reduce the compensation residual error generated from the thermal hysteresis nonlinearity between the sensing fiber and reference fiber. In the experiment, the strain sensor network possesses a sensing capacity with 55 sensor elements. The phase bias drift with frequency below 0.1 Hz is effectively compensated by LS-SVM based hysteresis model, and the signal to noise ratio (SNR) of a strain vibration at 0.01 Hz greatly increases by 24 dB compared to that of the sensing fiber for direct compensation. The proposed strain sensor network proves a high dynamic resolution of 10.5 pε·Hz-1/2 above 10 Hz, and ultra-low frequency sensing resolution of 166 pε at 0.001 Hz. It is the first reported a large sensing capacity strain sensor network with sub-nε sensing resolution in mHz frequency range, to the best of our knowledge.

E‐healthcare platforms start to integrate medical services across online and offline channels, where providers can perform online consultations, schedule patients’ offline visits, synchronize relevant medical records, and finally, answer online inquiries regarding follow‐up and recovery anytime and anywhere within one operations management function (i.e., online–offline service integration). In this study, we seek to quantify the effects of online–offline service integration on the e‐healthcare providers’ demand and reputational outcomes, noting that it is not altogether clear how the service integration function will affect the providers who adopt such a function in e‐healthcare platforms. Leveraging a quasi‐natural experiment on an e‐healthcare platform, we conducted difference‐in‐differences analyses in tandem with a variety of matching strategies, including propensity score matching and look‐ahead propensity score matching. Furthermore, we explored the moderating roles of provider‐specific characteristics. Our results reveal a set of robust and interesting findings: (i) e‐healthcare providers, on average, experience increases in online demand and decreases in offline demand post online–offline service integration; (ii) the service integration function also improves the professional reputation of participating providers; (iii) the impact of channel integration on the outcomes is weaker for providers with lower (vs. higher) professional titles; and (iv) the providers who specialize in treating chronic (vs. acute) diseases experience greater increases in online demand and reputational outcomes, yet insignificant changes in offline demand. This work contributes to related prior literatures on healthcare operations management, e‐healthcare, and online–offline channel integration, offering design implications for the service operations of e‐healthcare platforms.

Optical fiber distributed acoustic sensing (DAS) based on phase-sensitive optical time domain reflectometry (φ-OTDR) is in great demand in many long-distance application fields, such as railway and pipeline safety monitoring. However, the DAS measurement distance is limited by the transmission loss of optical fiber and ultralow backscattering power. In this paper, a DAS system based on multispan relay amplification is proposed, where the bidirectional erbium-doped fiber amplifier (EDFA) is designed as a relay module to amplify both the probe light and the backscattering light. In the theoretical noise model, the parameters of our system are carefully analyzed and optimized for a longer sensing distance, including the extinction ratio (ER), span number, span length, and gain of erbium-doped fiber amplifiers. The numerical simulation shows that a bidirectional EDFA relay DAS system can detect signals over 2500 km, as long as the span number is set to be more than 100. To verify the effectiveness of the scheme, a six-span coherent-detection-based DAS system with an optimal design was established, where the cascaded acoustic-optic modulators (AOMs) were used for a high ER of 104 dB. The results demonstrate that the signal at the far end of 300.2 km can be detected and recovered, achieving a high signal-to-noise ratio of 59.6 dB and a high strain resolution of 51.8pε/Hz at 50 Hz with a 20 m spatial resolution. This is, to the best of our knowledge, a superior DAS sensing distance with such a high strain resolution.

Mode-locked lasers with ultra-narrow spectral widths and durations of hundreds of picoseconds can be versatile light sources for a variety of newly emergent applications. However, less attention seems to be given to mode-locked lasers that generate narrow spectral bandwidths. We demonstrate a passively mode-locked erbium-doped fiber laser (EDFL) system that relies on a standard fiber Bragg grating (FBG) and the nonlinear polarization rotation (NPR) effect. This laser achieves the longest reported pulse width (to the best of our knowledge) of 143 ps based on NPR and an ultra-narrow spectral bandwidth of 0.017 nm (2.13 GHz) under Fourier transform-limited conditions. The average output power is 2.8 mW, and the single-pulse energy is 0.19 nJ at a pump power of 360 mW.

Continuous monitoring of blood pressure has significant clinical value for the cardiovascular disease prevention and diagnosis in daily life. However, conventional blood pressure measurement is unsuitable for long-term monitoring due to its discomfort and poor portability. Wearable device is an ideal solution to overcome this problem, which has attracted increasing interests of many researchers. While, high-performance wearable blood pressure sensor still remains a challenge. Here, we present a wearable blood pressure wristband system based on optical fiber. The end face of optical fiber was coated with a Polydimethylsiloxane (PDMS) + Ag composite diaphragm. The continuous and accurate measurement of the pulse waveform was achieved through the phase variation of the light reflected from the diaphragm. Then, the blood pressure can be estimated from the pulse transit time (PTT) which is extracted from the high-fidelity pulse waveform. The estimation model was established using data from 45 subjects. The clinical experiment was also carried out on 17 subjects to test the performance of the proposed wearable blood pressure wristband. The results show that the errors of systolic pressure (SBP) and diastolic pressure (DBP) are 0.24 ± 2.39 mmHg and 0.12 ± 2.62 mmHg compared with commercial sphygmomanometer, respectively. The measurement errors were within the required range of the Association for the Advancement of Medical Instrumentation (AAMI) and the British Hypertension Society (BHS) Grade A, which indicates that the blood pressure wristband has a good accuracy and practicability. This wearable and user-friendly optical fiber blood pressure monitor is a competitive alternative to current commercial products.

The performance of free-space optical data transmission is severely deteriorated by the fluctuation of optical signal intensity, which is resulted from the bias drift of electro-optical modulation devices. In order to improve the performance of free-space optical communication systems, a bias-drift avoiding, beam steered free-space optical wireless communication system is presented based on polarization modulation for the first time to the best of our knowledge. An in-fiber diffraction device based on a 45° tilted fiber grating (TFG) serves simultaneously as an in-fiber polarizer, free-space light emitter, and beam steerer in the proposed communication system, which endows the proposed system with the merits of highly efficient, compact, stable and bias-drift free. The usage of 45° TFG has three benefits: 1), it realizes polarization modulation preventing bias-drift due to its polarization sensitive feature; 2), it enables stable and highly efficient in-fiber compact free-space light emitter; and 3) it accomplishes free-space beam steering due to its wavelength-depending diffraction characteristic. A 2.1 m free-space optical wireless data transmission has been demonstrated with a data rate of 4.8 Gbps per beam using 1.2 GHz bandwidth OFDM signals. This proposal prevents the bias drift issue and maintains high stability. Hence, it can be applied in some harsh situations and confidential data transmission fields.

Noninvasive real-time distributed pipeline monitoring technology is a key factor for the sustainable development of transportation pipelines. In this work, we have proposed and demonstrated a distributed microstructure optical fiber acoustic sensor (MOF-DAS)-based pipeline flow rate sensing system. Such proposed sensing system is based on the detection of flow-induced vibration (FIV) to achieve the flow rate measurement. We have used the Euler–Bernoulli beam theory to build up the FIV-based flow rate sensing model and numerically analyzed the pressures fluctuation at the wall under different flow rates. The simulation results showed that the standard deviation of pressure fluctuation is quadratically proportional to the flow rate. And we have experimentally verified and realized distributed flow rate detection in a pipe loop system built by a 25-m-long pipeline and a laboratory-made MOF-DAS system, which is the first time that the DAS is used for noninvasively pipeline flow rate detection. The experimental results are consistent with the simulated results very well. In the experiment, the flow rate range we measured was from 0 to 3.6 m/s, in which the measuring sensitivity of MOF-DAS at 3.6 m/s was around 0.03998 rad/( $\text{m}\cdot \text{s}$ -1). Furthermore, the uncertainty analysis of experimental results shows that the measuring uncertainty is decreasing as increasing of flow rate, which is around 13.75% at the flow rate of 0.8 m/s and reduces to less than 1% at the flow rate of 3.6 m/s. Compare with the results measured by the commercial accelerator, the MOF-DAS-based flow rate sensing system has a better and stable flow rate measuring results. Finally, the MOF-DAS-based distributed flow rate detection system has been successfully applied in the field test, which indicated huge engineering application potential, especially in long-distance pipeline networks.

An undersampling free-space optical (FSO) communication system based on compressive sensing (CS) and in-fiber grating is proposed. Our proposal drastically mitigates the data scale unfavorable issue and reduces the great amount of required data. Also, our proposal employs low-bandwidth and low-cost photodetectors (PDs) and analog-to-digital converters (ADCs) and decreases the cost of data detection. Besides, the data transmitted in the free space is encrypted, which enhances the security of the system. The in-fiber grating, which has the advantage of highly efficient thanks to its inherent compatibility with optical fiber links, plays the roles of light emitter, in-fiber polarizer, and light diffraction device, simultaneously. A sinusoidal radio frequency (RF) signal with a frequency of 1 GHz is utilized for a 2.4 m data transmission. And each PD with a bandwidth of 300 MHz is employed for detecting the transmitted signal on each channel. The proposal obtains data compression ratios of 25%, 15%, and 5% both in the temporal domain and frequency domain. Besides, a two-tone signal and a random RF signal are applied in the proposed FSO transmission for data transmission. Our proposal not only has the merits of secure, compact, stable, and highly efficient, but also has great potential in extremely secure situations, such as secured indoor and under water data communication.

We experimentally demonstrate meta-learning-enabled accurate optical signal-to-noise ratio (OSNR) monitoring of directly detected 16QAM signals with extremely few training data. When one-shot training, where one amplitude histogram (AH) for each OSNR value includes only 2000 data samples, is implemented for a 16QAM signal within a variable OSNR range of 15–24 dB, the experimental root mean squared error (RMSE) of the retraining technique is 1.53 dB. For transfer learning from the 16QAM simulation to the experimentally generated AH, the RMSE can be reduced to 1.11 dB. In comparison with both the retraining and transfer learning techniques, the RMSE of meta-learning-enabled OSNR monitoring can be further reduced by 42.8% and 22.3%, respectively. In order to reach the optimal accuracy with an RMSE of 0.66 dB, the meta-learning technique requires only 15 AHs for each OSNR value to be monitored, while the retraining and the transfer learning techniques need 20 and 25 AHs, respectively.

We report the experimental demonstration of a multiwavelength passively mode-locked fiber laser based on an all-fiber Lyot filter (AFLF). The Lyot filter is composed of two 45°-titled fiber gratings (45°-TFGs) and a length of polarization-maintaining fiber (PMF). The free spectrum range (FSR) and the 3-dB bandwidth of the Lyot filter are 7.5 nm and 3.6 nm, respectively. The laser generates 5-wavelength mode-locked pulses, which have 7.49 nm channel spacing, 192.6 kHz fundamental repetition rate and over 50 dB signal-to-noise ratio (SNR). As increasing the pump power from 178 mW to 407 mW, the pulse width and the average output power increased linearly from 10 ns to 23 ns and from $256\mu \text{W}$ to $621\mu \text{W}$ , respectively. In addition, the fluctuations of center wavelength and laser power are < 0.5 nm and < 0.5 dB respectively within a duration of 1 hour.

We have experimentally demonstrated an all-fiber mode-locked laser by using a 45°-tilted fiber grating (45°-TFG) based in-fiber polarization beam splitter (PBS). Based on the nonlinear polarization rotation (NPR), the slanted refractive index modulation structure of the 45° TFG is able to tap the pluses out from the side face of the fiber. The central wavelength of the laser is 1559.9 nm and the period of pulse train is 156 ns, corresponding to the fundamental repetition rate of 6.79 MHz, the pulse energy of 0.26 nJ and the pulse duration of 1.06ps. Additionally, the laser shows a high degree of polarization (DOP) output of 99.8%. This mode-locked fiber laser with single polarization mode output is reliable during long-term operation and thus promising for many practical applications. As a proof of principle, the demonstrated laser can provide neat solution in designing compact mode-locked fiber laser.

A smart mattress based on optical fiber Mach-zender interferometer (OF-MZI) is designed for noninvasive and continuous monitoring of human vital signs. Through arranging the sensing fiber between two elastic covering layers with sandwich structure, the mattress was sensitive to the respiration and heartbeat induced micro-pressure. In the processing terminal, the waveforms of vital signs were demodulated by 3 * 3 coupler based differentiate and cross-multiplying method, and then four characteristic indicators including the heart rate, heartbeat amplitude, respiration rate, and respiration amplitude were respectively extracted through feature extraction algorithm, for evaluating the human health condition. Clinical experimental results of eighteen subjects indicate that the mattress system could not only distinguish the activity states of no body, on bed, body movement and off bed, but also contribute to clinical diagnosis of bradycardia, tachycardia, polypnea and apnoea. By adopting Bland–Altman analysis method, good reproducibility and accuracy were confirmed, where the max errors of heart rate and respiration rate are respectively 2 bpm and 1 bpm. Moreover, the responses at different positions of the mattress are identical and the continuous monitoring results in one day are consistent with daily change of vital signs, which proves that the fiber optic mattress has good reliability and stability. Beneficial from high-sensitivity, multiple parameters, long-term continuous monitoring, high comfortability and low cost, the mattress is promising in the early detection and prevention of cardiac and respiratory diseases as a household medical device.

High polarization extinction ratio (PER) in-fiber polarizers are essential in various fiber-based technologies. In this letter, we propose and demonstrate an in-fiber dispersion compensated polarizer (DCP) based on integrated fiber gratings, which is fabricated by a UV-inscribed 45° tilted fiber grating (TFG) and a chirped fiber Bragg grating (CFBG) in series. Such compact device could enhance the PER of 45° TFG with nearly double value and it is potential to achieve ultra-high PER with relatively short length and simple fabrication. Meanwhile, DCP could also function as a dispersion management component. Finally, with the integrated grating device, we have demonstrated an all fiber mode-locked laser system, generating soliton pulses at the normal and anomalous dispersion regime, respectively.

A multi-switchable generation between dissipative solitons (DSs) and noise-like pulses (NLPs) in a fiber laser is demonstrated. A 45° tilted fiber grating is applied as an effective in-line all-fiber polarizer to realize the nonlinear polarization rotation (NPR) mechanism. With the fixed orientations of polarization controllers, the operation regimes of the fiber laser can be alternatively switched between DS and NLP by monotonically increasing pump power only. We observed five switching stages between DS/NLP regimes with the pump power elevating from 200 to 660 mW. Remarkably, the whole procedure could be precisely controlled forwardly and backwardly. This multi-shuttle behavior between the two distinct types of output pulse can be attributed to the transmission of NPR mechanism together with the gain filtering effect. To the best of our knowledge, this is the first report on the multi-shuttle behavior between DS and NLP in a fiber laser under monotonic change of pump power. Our findings may contribute to in-depth understanding of nonlinear dynamics and laser physics.

Highly sensitive distributed acoustic sensor is required in various practical applications. In this article, an ultra high sensitive quasi distributed acoustic sensor based on coherent detection and cylindrical transducer is proposed and demonstrated. As the acoustic sensing medium, distributed microstructured optical fiber (DMOF) is utilized to improve the signal to noise ratio (SNR) of the signal, which contains backscattering enhanced points (BEPs) along the longitudinal direction of the fiber. In order to increase the acoustic sensitivity, the hollow cylindrical structure is developed for acoustic wave transduction. In addition, coherent phase detection is adopted to achieve the high precision phase signal demodulation, and thus to realize high-fidelity recovery of the airborne sound wave. Consequently, the spatial distributed acoustic sensing can be realized, which integrates a series of high-sensitive sensing units in a single fiber. The field test results of the airborne sound detection illustrate an excellent phase sensitivity of −112.5 dB ( re 1 rad/μPa) within the flat frequency range of 500 Hz–5 kHz and a peak sensitivity up to −83.7 dB ( re 1 rad/μPa) at 80Hz. The waveform comparison between the measurement result and the standard signal shows the maximum error of only 3.07%. Besides, distributed audio signal recovery and spatial acoustic imaging are demonstrated, which can be further applied in the field of fiber distributed microphone and urban noise intensity holography.

We have proposed and experimentally demonstrated an ultrasensitive all-fiber angular displacement sensor based on in-fiber polarizing gratings and half waveplate (IFHWP), in which the polarizing gratings are based on 45°-tilted fiber gratings (45°-TFGs) and the IFHWP is constructed by bending-induced birefringence in single mode fiber (SMF). Compared with the existing angular displacement sensors, the structure of our proposed sensor is more desirable to bring the prominent advantages of all-fiber structure, low transmission loss and high sensitivity. The experimental results show that the proposed angular displacement sensor has a sensitivity and a resolution up to 20.477 dB/rad and $2.8\times 10^{-3\circ }$ , respectively, within a large measurement range of about 25°. In addition, such sensor also has very low temperature sensitivity around $2.1\times 10^{-4}$ dB/°C.

Staphylococcus aureus is a common foodborne pathogenic microorganism which can cause food poisoning and it is pathogenic to both humans and animals. Therefore, rapid detection of S. aureus infection is of great significance. In this study, a microfluidic platform was introduced to detect S. aureus by fluorescence labeling method and a self-made microfluidic chip, which has immune spheres were used to study the effect of capturing S. aureus. Through this experiment, we found that the platform can be used for microbial culture, and S. aureus antibody coated on the diameter of 50 ~ 90 μm microspheres for detection. On the premise of optimizing the sample flow rate and detection time, the bacterial detection was quantitatively monitored. Results showed that our platform can detect S. aureus at injection rate of 5 μL·min−1 reacted for 4 min and the detection limit of bacteria is 1.5 × 101 CFU/μL. However, the detection time of traditional method is 24 hs to 72 hs, and the operation is complex and cumbersome. These findings indicated that the microfluidic chip in this study is portable, sensitive, and accurate, laying a good foundation for further research on the application of rapid bacterial detection platform.

Background The study aimed to investigate the correlation between both particulate matter (PM) 2.5 and temperature and the incidence of severe asthma as diagnosed by fractional exhaled nitric oxide (FeNO) values of >50 parts per billion. Methods This large-scale retrospective study used data on PM2.5 and temperature from the Shanghai Meteorological Bureau in China that had been collected between May 2014 and April 2016. All patients with suspected airway inflammation, who had visited the Minhang branch of Zhongshan Hospital, an affiliation of Fudan University, between May 2014 and April 2016, were retrospectively enrolled in this study. Spearman’s rank correlation coefficient and multiple linear regression models were used to analyze the synergistic effect of PM2.5 and temperature on the incidence of severe asthma in the different subgroups of patients with suspected airway inflammation. Results PM2.5 and temperature were significantly correlated with the incidence of asthma in the Oldabove50 subgroup (Spearman’s r = 0.580, p = 0 .003 and Spearman’s r = -0.689, p ≤ 0.001, respectively), when analyzed using non-parametric statistical analysis methods. The combined effect of PM2.5 and temperature on the incidence of asthma was significantly greater in the Oldabove50 subgroup (R = 0.693) than in the Adultabove50 subgroup (R = 0.275) (F > Fα; Fα = 2.997066, p < 0.05). In particular, in the Oldabove50 subgroup, the effect of temperature on the incidence of asthma was greater than that of PM2.5, when using beta coefficients (p = 0.004). Conclusions The FeNO cut-off value can be used to determine the effect of PM2.5 and temperature on patients’ respiratory health. Although the study’s limitations may have impacted these findings, and further investigation is necessary, this study provided a convenient investigation into the epidemiology of asthma. Such research is important for public health.

Biosensors play a significant role in biomedical, clinical and disease diagnosis areas. Here, we proposed Langmuir adsorption model to explain sensing mechanism of biosensor based on excessively tilted fiber grating (Ex-TFG) functionalized with graphene oxide (GO). Due to GO containing plenty of six-membered rings and oxygen-containing groups, the biomolecules can be easily adsorbed through π-π interaction and hydrogen bond. The whole interaction process obeys the Langmuir adsorption model in which there always an equilibrium during detecting process, inducing the sensor with adjustable bio-sensitivity and detection range. Three biosensors based on Ex-TFG coated with three different amount of GO were investigated for hemoglobin (Hb) detection experiment, showing pronounced bio-interaction induced resonance shifts. The experiment results indicate that GO coating could enhance the surface biological activity of Ex-TFG, making the Ex-TFG sensitive to the Hb biomolecule solutions. The three GO coated Ex-TFG sensors have the bio-sensitivity of 3.83 nm/(mg/ml), 4.33 nm/(mg/ml), and 8.21 nm/(mg/ml), and the detection range of 0.8 mg/ml, 0.6 mg/ml and 0.4 mg/ml, respectively, which are in good agreement with the prediction from the Langmuir adsorption model. By controlling the amount of the bio-functionalized materials, the bio-sensitivity and detection range of the Ex-TFG based biosensors can be easily adjusted.

A dye-doped polymer based optical fiber transducer is demonstrated for PA-US dual-modality imaging, which an ultrasound generation efficiency of 0.064MPa mJ-1cm2 with a bandwidth of 33.5MHz as well as an optical transmittance of 83.1%.

A non-invasive online method for pipeline corrosion detection based on active acoustic flaw detection is proposed and demonstrated. The test results show that the proposed method can identify corrosion with a size less than 0.5%.

We demonstrate a fully continuous fiber-optic streamer with small channel spacing of ≤ 1m and ultra-high sensitivity of −137 dB rerad/(μPa·m), whose field test exhibits tremendous potential for the marine seismic acquisition.

An intrusion events recognition method by incremental learning is proposed and demonstrated. Assisted with fiber optic distributed acoustic sensing (DAS) system, the average recognition accuracy of 91% is achieved with only 28.7% training set in the field test.

Using an Er-doped fiber laser passively mode-locked fiber laser based on nonlinear polarization rotation (NPR) as a testbed, here we, for the first time, experimentally demonstrate the effect of the slow scale (thousands round-trip time) polarization instabilities on the emergence of breather-like spatiotemporal structures.

We reported a high-resolution laser ranging method utilizing the noise-like pulse stretched by the dispersive Fourier transform technique. The experimental results demonstrated a 1-cm spatial resolution within 2.861m range.

We demonstrate fiber crust deformation detection system based on coherent phase detection. With sensitivity enhancement design and compensation scheme, the system can reach a strain resolution of 151pε@ 0.01Hz, which could record the crust deformation.

A non-invasive online method for pipeline micro leakage detection and localization is proposed and demonstrated. The experimental results indicate that the proposed approach can successfully detect and locate the micro leakage with the diameter of 0.5 mm.

We report the implantable optical fiber sensor for monitoring the cathode stress evolution in the lithium-sulfur battery. The operando decoding of the chemo-mechanics events of Li-sulfur battery is successfully realized.

A highly accurate 3D shape sensing scheme based on special fiber OFDR is proposed and demonstrated. Combining with ICP algorithm, the maximum reconstruction error is effectively reduced to 0.29% within a length of 200 mm.

Ferroptosis is caused by lipid peroxidation and iron accumulation and can cause cell death. Abnormally expressed iron transporters are involved in ferroptosis in a variety of diseases. ZRT/IRT-like protein 14 (ZIP14) is a transport protein that can mediate cellular uptake of iron, zinc, and manganese. Herein, we have tested the hypothesis that the divalent metal transporter ZIP14 is involved in the initiation of ferroptosis in diabetic nephropathy (DN). DN was induced in 8-week-old male rats by streptozotocin before analysis of the degree of renal tubular injury. In addition, an in vitro model of DN in human kidney proximal tubular cell line was used. We showed that ZIP14 was up-regulated and ferrous iron (Fe2+) levels increased both in vivo and in vitro. Expression of glutathione peroxidase 4 and the level of glutathione were reduced, whereas that of malondialdehyde (MDA) increased. Ferrostatin-1 (Fer-1) treatment reduced the expression of ZIP14 and the levels of Fe2+ and MDA, which is consistent with ferroptosis. Fer-1 improved kidney function in DN rats. This was characterized by urine levels of protein-to-creatinine ratio, α1-microglobulin, and N-acetyl-β-D-glucosaminidase. Our study demonstrates a novel role for ZIP14 in diabetic kidney injury mediated by ferroptosis, and suggests a potential new therapeutic approach for the treatment of diabetic nephropathy.

Distributed fiber optic sensor for multi-parameter measurements plays a crucial role in various applications. In this work, distributed temperature/vibration fiber optic sensor with high precision and wide bandwidth is proposed and experimentally demonstrated. To improve the signal-to-noise ratio (SNR) and sensitivity of the system, the backscattering enhanced optical fiber (BEOF) is employed to provide strong and stable sensing signal. With the assistance of the coherent phase detection, a high precision measurement of phase can be achieved. In addition, the wavelet packet decomposition algorithm is put forward to effectively discriminate the quasi-static temperature and dynamic vibration signals. In the experiment, wide bandwidth vibration signal from 0.01 Hz to 20 kHz can be successfully detected. Owing to the high sensitivity of the system, the local temperature change within the range of only 10 cm can be captured with high precision of 0.095 °C. Besides, the system has a good capability of fast response to the external temperature variation where the response time is around 0.3 seconds, which is meaningful for the early warning of centimeters-level sized fire source in the special oil and gas pipelines monitoring applications.