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A rare Reason behind Huge Bowel problems in the Patient With Ulcerative Colitis.
The fluorescence quantitative analysis method of a solution is widely applied in chemical analysis, clinical medicine testing, environmental monitoring, food safety detection, and so on. It is based on the linear relationship between the intensity of fluorescence emission and the concentration of the substance in solution. Without consideration of the spatial attenuation effect of excitation light, it is applied only to a dilute solution. In this research, a fluorescence emission model is established based on the interaction and propagation law between the excitation light and the fluorescent substances. The spatial attenuation effect of excitation light is analyzed by an element analysis method, and the spatial intensity distribution of fluorescence is revealed. Further, a high accuracy model between the received fluorescence intensity and concentration is obtained. Applications of this model and further design will allow for high throughput fluorescence analysis and the analysis of fluorescent substances with ultra-wide range concentration, such as on-line testing fluorescent dyes in the textile industry, monitoring protein plasma in biomedical field, and high-throughput DNA fluorescence analysis etc. As an example, based on this model, an ultra-wide concentration range (0.02 - 250 mg/L) detection of tryptophan with high accuracy (R2 = 0.9994, RRMSE = 0.0356) is realized.We propose a time-of-flight measurement algorithm for depth and intensity that is robust to fog. The key idea of the algorithm is to compensate for the scattering effects of fog by using multiple time-gating and assigning one time-gated exposure for scattering property estimation. Once the property is estimated, the depth and intensity can be reconstructed from the rest of the exposures via a physics-based model. Several experiments with artificial fog show that our method can measure depth and intensity irrespective of the traits of the fog. We also confirm the effectiveness of our method in real fog through an outdoor experiment.A wavelength tunable single-longitudinal-mode (SLM) ErYAG ring laser around 1.6 µm is demonstrated. By using an acousto-optic modulator (AOM) to force unidirectional operation, up to 10.4 W and 8.7 W SLM laser output power are obtained at 1645.22 nm and 1617.33 nm, with corresponding slope efficiencies of 45% and 40%, respectively. Besides, stable dual-wavelength operation at both 1645 nm and 1617 nm is also achieved with the maximum power of 9.1 W. By rotating the birefringent filter (BRF) in the ring cavity, the wavelength could be tuned from 1616.77 nm to 1617.51 nm and 1644.51 nm to 1646.12 nm. The line width is measured to be 125 kHz at 1617 nm and 131 kHz at 1645 nm via the time-delayed self-heterodyne method. As far as we know, 8.7 W is the highest continuous-wave SLM output power at 1617 nm.Absorbers have high potential application values in the military field, such as electronic screening, radar cross-section reduction and invisible cloaking. However, most methods have the defects of narrow bandwidth, low absorptivity, complex three-dimensional structure and fixed polarizations. In this paper, we realize an ultra-broadband and full-polarization planar metamaterial absorber (PMA) with a three-layer composite structure, which exhibits multi-resonant and impedance matching properties by combining the ultra-light foams and indium tin oxide (ITO) films. The bottom two layers achieve a high-efficiency absorption rate at the low and medium spectrum, while the upper layer realizes a absorption property at a high frequency. Also, an equivalent circuit model is extracted to explain its operating mechanism. The experimental results show that our meta-absorber can achieve great absorber performance of better than 90% within 1-18 GHz for full-polarization incident waves, which is in great agreement with the numerical simulations. Moreover, our device is insensitive to oblique incidences and polarizations and possesses the physical characteristics of an ultralight, weighing 0.6 kg for a square meter, which is only 1/85.0-1/126.7 of the conventional absorbers under the same size. All these excellent performances determine that our research can be a good candidate for military stealth materials.Photonic structures have been attracting more attention due to their ability to capture, concentrate and propagate optical energy. ITD-1 TGF-beta inhibitor In this work, we propose a photon-trapping hole-array structure integrated in a nip InAsSb-GaSb heterostructure for the enhancement of the photoresponse in both near- and mid-infrared regions. The proposed symmetrical hole array can increase the photon lifetime inside the absorption layer and reduce reflection without polarization dependence. Significant enhancements in absorption and photoelectric conversion efficiency are demonstrated in dual bands for unpolarized incidence. The enhancement factors of responsivity at room temperature under zero-bias are 1.12 and 1.33 for the near- and mid-infrared, respectively, and they are increased to 1.71 and 1.79 when temperature drops to the thermoelectric cooling temperature of 220 K. Besides, such an integrated hole array also slightly improves working frequency bandwidth and response speed. This work provides a promising way for high-efficiency polarization-independent photoelectric conversion in different electromagnetic wave ranges.Stationary source emissions of key industries, such as thermal power plants, have become the central consideration in environmental protection programs. Existing photoelectric sensors at stationary sources usually use a single wavelength laser to measure the total mass concentration of the particulate matter, bearing inherent errors due to the changing particle size distribution (PSD). However, the total mass concentration cannot comprehensively estimate the air pollution caused by the stationary sources. Therefore, it is required to measure both the mass concentration and PSD of the aerosols emitted by the stationary sources, based on which we can get a distributed mass concentration. To implement this, in this study, we designed a novel three-wavelength photoelectric sensor and tested its performance. Results showed that the prototype correctly determines the mean particle size and standard deviation of the PSDs and consequently adjusts the coefficient for measuring the mass concentration from light intensity, providing a comprehensive assessment of the pollutants.Following the rise in interest in transmission systems employing the nonlinear Fourier transform (NFT) for the nonlinearity mitigation, we present the theoretical analysis of the achievable information rates in these systems, addressing the case of continuous b-modulated systems. Using adiabatic perturbation theory and the asymptotic analysis by means of Riemann-Hilbert problem, we obtain a remarkably simple input-output relation for arbitrary b-modulated transmission. Based on this model, we estimated the spectral efficiency for various single polarization (scaled and unscaled) b-modulated systems and observed an excellent agreement between our theory and the numerical results in the regime when the inline amplifier noise is the dominant source of spectral distortion.The laser acquisition-pointing technique is one of the most important techniques for space gravitational wave detection missions, like the Taiji program and the LISA (Laser Interferometer Space Antenna) program. The laser acquisition system suppresses the laser deviation angle to 1 µrad at the receiving aperture. Corresponding to 80 times of telescope magnification, the acquisition accuracy should reach 80 µrad at the acquisition camera. In order to verify the feasibility of the laser acquisition scheme, a laser acquisition ground simulation experimental system is designed and constructed. The experimental system simulates the actual acquisition process of the Taiji from three aspects optical path, acquisition accuracy and acquisition scanning process. In the experiment, the coupling between the laser acquisition system and the laser pointing system is considered by introducing the DWS (Differential Wave-front Sensing) technique to calibrate the reference position of the acquisition camera and read out the acquisition precision. Due to limited beam propagation distance in the ground experiment, the in-flat top properties of the transmitting beam will greatly affect the acquisition precision. Based on the analysis of the influence, an improved acquisition ground simulation scheme is introduced. The experimental results indicate that the experimental system can achieve the acquisition accuracy of sub-10 µrad magnitude at the acquisition camera. The experimental system realizes methodological demonstration of the acquisition scheme. The results offer the experimental foundation and theoretical basis for the acquisition system of the Taiji/LISA program.Herein, we verify that a Raman/EDFA hybrid amplifier can improve the stability of fiber-optic time and frequency synchronization systems compared to the Er3+-doped fiber amplifier (EDFA), owing to its higher gain and lower noise figure (NF) performance. We studied the variation law of Raman gain efficiency for a fiber Raman amplifier (FRA) as a function of pump power and input signal power, designed a bidirectional Raman/EDFA hybrid amplifier, and proved that equivalent NF below 0 dB can be obtained. Finally, hybrid amplifiers were compared to EDFAs in a free-running frequency synchronization system. The transfer stabilities reached 1.9678 × 10-13/1 s and 2.0248 × 10-13/1 s when FRA + EDFA and EDFA + FRA configurations were used, respectively, both exhibiting better performance than the stability of 3.0905 × 10-13/1 s obtained by EDFA.A multi-channel interference (MCI) widely tunable semiconductor laser is described in detail with improved performance in this paper. The MCI laser without the common phase section was packaged into a standard 14-pin butterfly package. The device realized a tuning range of more than 40 nm with side mode suppression ratios (SMSRs) higher than 48 dB and about 7 dBm fiber power. By making the gain section and the phase sections to be surface ridge waveguides, threshold currents of the laser have become less than 18 mA across the tuning range. Besides, tuning characteristics of the MCI laser were experimentally studied in detail for the first time. The MCI laser can be treated as a combination of eight Fabry-Pérot (FP) cavity lasers which share the same gain section. It is found that when the eight arm phase sections are completely in phase at the lasing wavelength, the operating currents are at maxima of the output power curves. The relationship between the lasing wavelength and the injection currents of the eight arm phase sections has been introduced and analyzed.Pre-chirp managed amplification (PCMA) allows the generation of optical pulses with a duration well below 100 fs. However, the pulse peak power is limited to 30 times improvement in both pulse energy and peak power compared with current Yb-fiber PCMA systems.Thin-film lithium niobate (TFLN) modulators are expected to be an ideal solution to achieve a super-wide modulation bandwidth needed by the next-generation optical communication system. To improve the performance, especially to reduce the driving voltage, we have carried out a detailed design of the TFLN push-pull modulator by calculating 2D maps of the optical losses and Vπ for different ridge waveguide depths and electrode gaps. Afterwards the modulator with travelling wave electrodes was fabricated through i-line photolithography and then characterized. The measured Vπ for a modulator with 5-mm modulation arm length is 3.5 V, corresponding to voltage-length product of 1.75 V·cm, which is the lowest among similar modulators as far as we know. And the measured electro-optic response has a 3-dB bandwidth beyond 40 GHz, which is the limitation of our measurement capability. The detailed design, fabrication and measurement results are presented.
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