To reduce the influence of linear birefringence of sensing fiber on the measurement accuracy of all-fiber current transformers, a spun high birefringence (SHB) fiber can be used as the sensing fiber of transformer. A mathematical model of transformer is established based on Jones matrix. The influences of plane mirror and Faraday rotator mirror on the measurement accuracy of reflection interference type transformer are studied. The relationship between the rotation ratio of SHB fiber and the ability of resistance temperature disturbance of transformer is analyzed, and the error compensation scheme for the SHB-type transformer which uses the fiber 1/4 wave plate is discussed. Results show that, for the plane mirror type transformer, the harmonic division method and the closed-loop signal modulation can eliminate the length sensitivity of SHB fiber. When the rotation ratio is larger than 30,the scale factor variation is less than 0.2% in the temperature range of -40~60 ℃. For the Faraday rotator mirror type transformer, the minimum rotation ratio for SHB fiber is 3.4 under the same condition. It indicates that the Faraday rotator mirror improves the temperature stability of transformer, and the scale factor temperature error of transformer caused by linear birefringence can be compensated when we choose an appropriate fiber 1/4 wave plate.

A three-mode division multiplexer and demultiplexer based on two-dimensional square-lattlie photonic crystal with wavelength of 1550 nm was designed. Two asymmetrical directional couplers are included, which can achieve modes conversion function of TE0, TE1 and TE2 modes. In order to avoid phase mismatching in bus waveguide, taper structure is applied at waveguide junction which can reduce the insertion loss effectively. Plane waves method and finite difference time domain methods are used to simulate the performance. Numerical simulations show that the designed device has the potential for high-capacity mode division multiplexing optical communication systems with insertion loss less than 0.14 dB and mode crosstalk less than -20 dB.

A method for chirped fiber Bragg grating (FBG) fabrication using an uniform phase mask is proposed. In the scanning exposure process, the phase mask jitters periodically along the length direction, and the jittering amplitude varies with the grating scanning length, which causes the phase of FBG changing with the position of the mask. As a result, the period of FBG is modulated linearly, and a linely chirped FBG is obtained. The chirped coefficient of FBG is determined by the variation of the jittering amplitude of phase mask. Three different jittering functions of phase mask are designed, and FBGs with different chirp values are fabricated in experiment.

A 90° mixer plays an important role in achieving a high sensitivity detection in space coherent laser communication. The relationship between signal light polarization state and mixing efficiency of space coherent detection is studied. The circularly polarized light is more stable than the linearly polarized light used in traditional programs, and it is beneficial to achieving a high efficient mixing. A method that a 1/4 wave plate is introduced at the signal input end is proposed to change the polarization state of the signal light, and the simulation for the change of signal light polarization state is carried out when the signal light is influenced by external factors. The calculated signal power is used as a parameter, and the influence of the signal light polarization state on the mixing efficiency is studied. When incident local oscillator lights are same and other limited conditions are ignored, we come to a conclusion that the maximum relative signal power can be obtained by the mixer when the mixer receives circularly polarized signal light, and its mixing efficiency is the highest.

A selection algorithm of mode selection threshold is proposed to applied to adaptive modulation coding technology for atmospheric laser communication is proposed. The performance of atmospheric weak turbulence channel is analyzed, the threshold selection algorithm for Gauss channel is modified. A selection method named signal to noise ratio-turbulence intensity is proposed to determine the mode for threshold region, and a equation for threshold selection is presented. The bit error rates of the adaptive modulation coding system are analyzed under three transmission modes when the turbulence intensity is 0, 0.1, 0.2, 0.3 respectively. The corresponding relationships between signal-to-noise ratio and turbulence intensity threshold region of the three transmission modes are obtained under the condition that the maximum bit error rate is 10-4. Simulation results show that the proposed method is feasible, and it can accurately realize mode selection.

The traffic sign recognition (TSR) system is an important research direction in the field of intelligent transport system. Due to traffic complexity, large scale of traffic signs database and other reasons, the feasibility of TSR design must take computational complexity and recognition rate into consideration. An efficient and fast traffic sign algorithm is proposed based on the improved principal component analysis (PCA) and extreme learning machine (ELM), as known as PCA-ELM. Firstly, the histogram of gradient direction (HOG) features for each TSR are extracted from traffic sign database. HOG dimensional features are reduced by the improved PCA algorithm. ELM model training is presented based on the HOG after dimension reduction. Image recognition is tested based on the trained ELM model. Experimental results show that the recognition algorithm based on PCA-HOG and ELM model can get a high recognition rate of 97.69% and perform low in computational complexity.

To achieve a robust and precise face tacking, the color information, gradient direction information and spatial structure information of face are fully exploited. The eyes, nose and mouth patches are employed as tracking regions from human face. The dominant features in these patches are extracted as the basis for tracking. Markov random fields are used to build the spatial constraints between these patches, and a robust tracking algorithm is realized. Experimental results show that, compared with several typical tracking algorithms, the proposed algorithm has well performance in robustness and precision.

In order to obtain the complex regions of cover image in adaptive steganography and improve the coherence between pixels, a novel adaptive steganography algorithm based on non-directional filter is proposed. The complex regions, which are difficult to be modeled and detected, are obtained by filter calculation on images through using a non-directional filter. The Gaussian low-pass filter is used for smoothing the complex regions, and enhance the coherence of different pixels in those regions and the cost function is established. Finally, according to the cost function, the messages are embedded by syndrome trellis codes. Experimental results demonstrate that the performance of anti-detection by the proposed algorithm is similar as that of the S-UNIWARD algorithm when the information embedding rate is small, and the proposed algorithm is better than the S-UNIWARD algorithm when the information embedding rate is large.

In order to solve the problem of difficulty of both the high perception robustness and tampering identification rate in the current image Hash algorithm, the compact image Hash algorithm based on data projection dimension reduction mechanism and fuzzy symmetric local binary pattern is proposed. The generated Hash has a fixed length by introducing the bilinear interpolation mechanism to preprocess the image. And the pretreatment image is transformed into the secondary image by the log polar transformation. The secondary image is smoothed by Gabor filter. The fuzzy symmetric local binary pattern operator is designed based on the fuzzy theory. And the compact intermediate Hash sequence is got by defining the data projection dimension reduction mechanism. The image Hash is generated by diffusing the bit Hash based on designing the one-dimensional combined chaotic map. The similarity between the original image and the image of the receiving end is estimated by introduction the Hamming distance and decision threshold to finish the authentication of image. Testing data show that this algorithm has stronger perception robust and sensitivity with tighter Hash length than the current image Hash technologies.

Aiming at the problem of motion image deblurring, a fuzzy kernel method based on L0 norms regularization term is presented. This method applies the image gradient L0 norms as the regularization term to construct a non-convex optimization energy function through the sparse prior condition of the image and the appropriate parameter estimation method. In the process of solving the function, the alternating iteration method is used to update the original image and the estimated values of the fuzzy kernel. In the process of original image estimation, the sparse regularization term of the image gradient L0 norms can effectively retain the sharp edges as well as suppress the influence of the weak edges on the fuzzy kernel estimation, which can obviously improve the accuracy of kernel estimation. In the process of fuzzy kernel calculation, the optimization energy function of fuzzy kernel converts to a classic convex optimization. Using the fast Fourier transform to compute the energy function can quickly get the estimated kernel. After getting the appropriate kernel of image, the problem of image blind deconvolution can be converted to the image non-blind deconvolution. A hyper-Laplacian priors using L0.5 as the regularization term is applied in deconvolution. This algorithm can well model the heavey-tailed distribution of gradients in natural scenes so that a perfect result can be obtained. Experimental results demonstrate that the proposed method gets higher quality deblurring results than the previous methods.

Order subset expectation maximization (OSEM) iterative algorithm is rapidly developed in recent years. But this algorithm is easy to generate some striation artifact, metal artifact or scattering artifact during iterative process. So a new iterative method named smooth constrained OSEM (SC-OSEM) is built, which utilizes smoothing constrained matrix as priori information in OSEM reconstruction. Median filtering algorithm and total variation minimization algorithm (TVM) are introduced as smoothing constrained conditions. The images reconstructed by computer tomography are consistent well with the initial model for the situations of incomplete projection data with ideal, metal, and noise, whose reconstruction qualities are better than only OSEM iterative algorithm. Median filtering constraint makes reconstructed image denoised, while TVM makes metal boundary clearer. These results manifest that SC-OSEM iterative algorithm is an adaptable and high precision CT reconstruction method.

To solve the problem that the finger vein image enhancement algorithm based on guided filter fails to highlight the vein texture details, the weighted guided filter algorithm based on edge detection is proposed. Through calculating the amplitude value of the vein image edge operator to punish the fixed neat parameter in the guided filter, the adaptive neat parameters of the vein texture area and the smooth area are obtained respectively, which makes the filter possess a better edge protection feature. This algorithm can reduce the noise, and simultaneously retain and highlight more vein texture details of images. A comparison experiment between two finger vein image enhancement algorithms proposed here and based on the guided filter is conducted in domestic and foreign image databases, and the results indicate that, under the condition of time complexity being constant, the former has a lower false recognition rate.

Different from the artificial classification of the inscription and seal, the computer classification uses image content characteristic as a source of information and is a key work in the digital management. Aiming at the non-standard problems and deficiencies of the existing feature extraction algorithms, a segmentation filtering method based on image entropy is proposed. The texture characteristics of traditional Chinese paintings are extracted by the method combined with the complex network theory, and then a support vector machine is used to classify. Experimental results show that this method can effectively extract textural features and categorize Chinese paintings, and it still has a good performance in the case of non-standard images.

A three-dimensional (3D) scanning system based on a single camera of four planar mirrors is presented. The 3D scanning geometric path of the system is introduced. The 3D height acquisition algorithm, the relationship between spatial resolution and image resolution are analyzed. The techniques of algorithm optimization and 3D reproduction are also discussed. The result shows that, compared with those 3D scanning methods using laser scanning, this proposed system based on mirror parallax is an effective 3D acquisition method because it can capture the spatial structure and color texture of a surface simultaneously, and the structure is simple.

Based on the compressed sensing theory, a compressive imaging system with parallel visible light focal plane is proposed. The system reconstructs the original image based on block compressed sensing imaging. Due to the use of a panel detector, every small block of the image is sampled at the same time. In the part of the imaging experiment, 0,1 binary Bernoulli measurement matrices are served as the measurement matrices to reconstruct different target images. Experimental results show that the method of parallel blocked-based compressive imaging system not only decreases the number of sampling, but also aviods a great deal of memory space and calculation because of the excessive measurement matrices. And the proposed imaging system is suitable for high resolution image reconstruction.

In order to satisfy the requirement of high precision optical fiber fault diagnosis, we have developed a chaotic light source module, which is composed of a bandwidth chaotic signal source and a laser modulation circuit. Among them, the bandwidth chaotic signal source produces a chaotic electrical signal with flat frequency spectrum and 10 dB bandwidth up to 500 MHz. When the signal is amplified by the modulation circuit, the driving distributed feedback (DFB) semiconductor laser can output high power and broadband chaotic laser signal. When the chaotic source module is applied in optical fiber fault diagnosis, it can not only realize the detection of fiber breakpoints and mismatch junctions, but also achieve a range-independent spatial resolution of 0.35 m in the detection range of approximately 107 km. In addition, the chaotic source module can be conveniently applied to such fields as chaotic radar and chaotic secure communications.

The liquid crystal optical phased array, which has the ability of deflecting non-mechanical beam, can be applied to space laser communications acquisition-tracking system to realize fast, flexible, and multiple-user access. A fast-tracking method based on liquid crystal optical phased array is presented, and the method uses charge coupled device (CCD) as a beacon light detector. Proportional integral differentiation (PID) closed-loop control algorithm is used to generate beam angle of direction control point data. Agile deflection of the incident light beam can be achieved, which points to the center of the acquisition-tracking detector, thus the purpose of tracking is achieved. The theoretical simulation shows that PID closed-loop control system can suppress Gaussian white noise and the tracking accuracy is less than 6.5 μrad. Experimental results show that after around 10 ms adjustment, the system enters the state of steady tracking, and the tracking accuracy is less than 12.6 μrad.

The biaxial straightness of a numerical control machine tool is measured by a self-developed 6-degree-of-freedom (6DOF) motion error simultaneous measurement system based on single fiber-coupled dual-frequency laser. Through the linear fitting of the two-axis straightness error, the angle between the two fitting axes is obtained, and the vertical measurement of the two axes is indirectly realized. The corresponding error model is established by using ray vector tracing method, and the influence of installation and processing error of the pentagonal prism on the measurement error are analyzed. The experimental results show that our system has high accuracy. Compared with commercial measuring instruments, the difference between the measured results is within 1″.

The high-speed and high-accuracy geometric calibration is the key step for building projection display system, which is especially important for the panoramic display system that composed of a large number of projectors. In response to this, a geometric calibration method based on fisheye camera is proposed and its theoretical derivation is given. The proposed method firstly calibrates the fisheye camera, and then builds the sub-pixel level mapping relationship between projector and camera through capturing the structured light feature fringes on the display wall. Finally, the geometric calibration data for each projection channel is calculated. Experimental results show that the proposed method can provide a high-speed and high-accuracy solution for large-scale panoramic display system, and it has a good application value.

Cryogen spray cooling (CSC) was proved to be an effective method to avoid the hyper-thermal injury in epidermal layer during the laser treatment of port wine stain (PWS). A numerical analysis was performed to show the thermal history during the CSC process. The analysis reveals that CSC does not only reduce the surface temperature and protect the skin surface from burning but also makes a high energy density possible to improve the clinic outcomes. The impact of the heat transfer coefficient and the initial tissue temperature on the cooling effect of CSC was also examined. We find that the surface temperature decreases as the heat transfer coefficient increases and a high initial temperature improves the clinical outcomes by increasing the final temperature in the PWS layer. However, a high initial temperature might increase the possibility of heat injuries, which should be avoided by extending the cryogen spraying time.

With respect to varied components and weak edge in tumor areas during the segmentation of computed tomography (CT) image of liver cancer ablation, a level set algorithm using the improved Chan-Vese model was proposed to accurately extract the contour of the hepatic tumor. According to significant difference of Gaussian mean and standard deviation between liver and tumor, the Gaussian mixture model was used to distinguish the subjection of pixels between target and background, and the bound terms of length and shape of edge gradient were combined to construct energy functions. The priori knowledge of tumor was applied to determining the initial profile of target, so that the active contour can converge on the edge of target area. By virtue of the verification algorithm of experimental data set of liver CT image, it is feasible to extract irregular contour of components such as inactivated or partially inactivated carcinoma tissues and iodized oil accumulation in liver. Experimental results showed that the average similarity value of our approach was higher than 0.87, the accuracy and precision of the improved algorithm were better than those of local Chan-Vese and local binary fitting models.

The electronic endoscope can only observe the front field of view. In order to eliminate patients′ injury from the blind area in the rear, an electronic endoscope which can observe both the front and rear field of view at the same time is designed. The first lens is designed according to the method similar to double agglutination. Circular reflective film is added to the front surface of the lens to meet the need of transmission and reflection. The endoscope chooses spherical design to reduce the cost. The system is optimized by Zemax stimulation, and equipped with 1/10 in (1 in=2.54 cm) charge coupled device (CCD) to receive image. The results show that the radial dimension of the system is 5.5 mm, which meets the requirement of small size. It also has uniform illumination at image plane on axis and off-axis. The modulation transfer function (MTF) value of this system is greater than 0.75 at the spatial frequency of 100 lp/mm at the whole view, which is close to the diffraction limit and meets the resolution requirement.

Magnitude simulator is the calibration and critical testing equipment on the ground for star sensor. A collimation optical system is designed to simulate the "infinity" starlight. In this system, four lens separation structure is used to meet the demand of weak light and improve the quality of image. The beam passes through the external exit pupil to the star sensor, and high-precision star image simulation is achieved. Based on the pulse width modulation (PWM) signal, a single-point controllable LED light is adjusted as the high-precision variable light source. With a contrast of 631∶1, the single-point control and joint control functions of the light source system are realized. The magnitude is tested in a darkroom. Results show that, under 10 μm star hole, the system can simulate 0-7 star magnitude. The magnitude of the tuning range is not less than half of a star, the simulation precision is less than 0.1 (the points of repeat tests fall within ± 0.4% of the required range), and the spectral range covers the entire visible spectrum.

Light emitting diode (LED) focusing lens with angle deflection for machine vision is designed by optical modeling software Light Tools. The lens is made of polymethyl methacrylate (PMMA). Firstly, the LED model is built according to the working distance and the illumination size. Secondly, a total reflection lens model is established with a lens model inside, and the illumination gridding optimization function is made to obtain the uniform illumination in the target area. Lastly, the lens is cut with tilted angle to meet the requirements of the angle based on the refractive law. The lens has simple structure, good uniformity, and it is easy to achieve the processing requirements. The lens meets the requirements of the angle deflection in the machine vision field.

The design principle of a grazing incident multi-included-angle plane grating monochromator is introduced, and the feasibility of the monochromator is analyzed and verified theoretically. This system is an improvement of SX-700 monochromator. Rising or falling the multi-angle plane reflection mirror can easily change the included-angle of covering a certain wavelength range, thus the desired wavelength of monochromatic light is chosen. Also, the monochromatization effect with X-LAB optical simulation software by monochromator at soft X-ray region 1-2.48 nm are simulated when the light incidents in the reflecting surface of a certain angular in multi-angle plane reflection mirror. This proves in theory that the wide energy spectrum scanning and high harmonics suppression can be realized with the proposed design. Furthermore, the structure of the monochromator is simple, which makes it easy to popularize for practical applications.

The property of two-dimensional quantum walks (QWs) with phase disorder is investigated and the research results indicate that this property depends on coin operations, coin initial state, and different types of phase disorder. Because of the symmetry-breaking of standard QWs, the localization effect can be observed. With the usage of initial-state-dependence of localization, the filter and trap of particles with QWs can be realized.

The key technology in practical optical fiber quantum private communication is the co-fiber-transmission technology for quantum signal and classical optical signal. The cost of quantum private communication network construction can be decreased remarkably by the co-fiber-transmission technology. The co-fiber-transmission principles of propagating classical optical signal together with discrete-variable quantum signal and continuous-variable quantum signal are compared. The co-fiber-transmission of discrete-variable quantum signal, continuous-variable quantum signal and classical optical signal based on mode division multiplexing in few-mode fiber (FMF) is proposed to reduce nonlinear damage and noise. This new scheme can use the fiber resource efficiently. A stable and efficient quantum private communication network is established when we integrate the technical advantages of discrete-variable quantum key distribution and continuous-variable quantum key distribution.

Negatively charged nitrogen-vacancy (NV) centers in diamond are attractive candidates because of their excellent spin and optical characteristics for quantum information and metrology. To research these characteristics, precise orientation of the NV axis in the lattice is essential. The information of axis orientation of two adjacent NV centers in diamond can be efficiently measured through multi linearly polarized beams, and the method can measure axial information of two adjacent NV centers from four possible axes.

One navigation scheme by integrating inertial navigation system (INS)/optical flow/magnetometer/barometer is proposed based on the extended Kalman filtering. Through data fusion of INS, optical flow and barometer, the speed and position of unmanned aerial vehicle (UAV) are estimated. When UAV is at rest or in motion with constant velocity, the UAV attitude is estimated by means of data fusion of gyro, accelerometer, magnetometer, and optical flow. When UAV is accelerated or decelerated, the gyroscope data is used to estimate the UAV attitude. The experimental results show that, the speed error for UAV is reduced from the maximum 20 m/s to 10 m/s, and the angle error is reduced from the maximum 80° to 10°. This scheme can effectively solve the cumulative error problem of velocity, position and attitude estimation.

The recent development status of the sensors based on metallic photonic structures integrated onto end facets of fibers is reviewed. On the basis of the differences in schemes of plasmon resonances and detection principles of sensors, the above sensors are usually categorized into fiber sensors based on surface plasmon resonance (SPR), fiber sensors based on localized surface plasmon resonance (LSPR), fiber sensors based on hybrid plasmons, and fiber sensors based on surface-enhanced Raman scattering (SERS) effect. In addition, the fabrication techniques, photophysical principles, and detection performances of these kinds of sensors are summarized, compared, and concluded.

In the last decade, the self-accelerating Airy beam is perhaps one of the most widely studied laser modes. Existing research show that Airy beams have propagation-invariant, self-healing and self-accelerating properties, which make them very useful in the fields of particle manipulation, plasma wave, laser-driven acceleration, optical routing, optical imaging, laser-guided sparks, matter-wave, quantum gravity and so on. In this article, an overview on self-accelerating Airy beams, their generation, characteristics and potential applications is provided and the potential perspective of the Airy beams is also presented.

The mid-infrared laser has the important application value and broad development prospects in military sensing range, environmental monitoring, atmospheric communication, biotechnology, medical, processing, and other fields because of its spectral coverage over many characteristic lines of molecular absorption. As for luminescence emission from the rare earth ions in chalcogenide glass fiber, it is an effective way to directly obtain mid-infrared lasing in the region of 3-5 μm. The latest progress of rare earth ions doped chalcogenide fibers and the main doping problems of chalcogenide fibers are reviewed, the current challenges in the development of mid-infrared chalcogenide glass fiber are discussed, and the research directions and development trends of the rare earth doped mid-infrared chalcogenide glass fibers are prospected.

Amplified spontaneous emission (ASE) is one key factor influencing the performance of high-peak-power high-energy pulsed fiber amplifiers with low repetition rate. The main methods used for ASE suppression in pulsed fiber amplifiers, including filtering, optimization of pump characteristics (pump power, backward pumping, and pumping schemes), and optimization of seed characteristics (signal power and signal pulse width) are reviewed. The suppression effect comparison among the above methods indicates that, filtering and synchronous pulse pumping are major technical means to suppress ASE and to achieve high-peak-power high-energy pulse outputs.

Laser pulse generated by phase modulation with certain spectrum distribution can suppress buildup of stimulated Brioullin scattering in large aperture laser optics and smooth the speckle pattern illuminating the target by spectral smoothing dispersion, but spectral distortion happening during the pulse transmission and amplification in each system of the laser facility can induce FM-to-AM effect, which will seriously affect the performance of the laser facility and physics experiments. The principal of phase modulated pulse, the reason why FM-to-AM effect happened and the factors which induced the FM-to-AM effect are introduced. And also the progress on suppression of FM-to-AM effect in National Ignition Facility, Laser Mégajoule laser megaioule facility and SG-Ⅲ laser facility are reviewed.

Myofascial pain syndrome (MPS) is a common syndrome characterized by chronic pain with high incidence and wide range of patients, which seriously affects the labor efficiency. Physical therapy is often used in clinical treatment for MPS. Low level laser therapy, one of the common physical therapies, has the effect of anti-inflammation, relieving pain and eliminating swelling. In recent years, it has become a new hot field of clinical research on MPS. We reviewed the basic research, laser parameters, and outcome measurements of low level laser therapy for MPS to provide a basis for optimizing the mechanism study, improving clinical therapy, and improving the clinical curative effect.

An algorithm of inverting atmospheric turbulence phase screen based on non-uniform sampling power spectrum is analyzed. Parallel progressing can be realized in the algorithm, and a graphics processing unit (GPU) is introduced. The speed of phase screen simulation can be effectively improved without affecting the simulation precision. Atmospheric turbulence phase screen is generated based on GPU technique while the Kolmogorov power spectrum is used. The simulation accuracy, simulation speed and error of phase screen are statistically analyzed and compared with theoretical values. Results show that the atmospheric turbulence phase screen simulated by GPU technique is consistent with the theoretical value, and has high simulation speed and high simulation precision. The generation speed of atmospheric turbulence phase screen is greatly improved.

In order to satisfy the requirement of the polarized light celestial positioning for the high-precision solar spatial position, one method based on the Rayleigh atmospheric polarization pattern is proposed. The experimental results indicate that, this method is capable of obtaining relatively reliable geographic position information with an average longitude error of 0.251° and latitude error of 0.171°. Although the precision of this method needs to be further improved, this method possesses important application value as a supplement to other positioning methods.

To develop a model for rapid, accurate grading of lumbers based on knots, near infrared spectroscopy was used to detect knots on coniferous wood surface. We explored the effects of spectral preprocess methods and modelling methods on knot detection, and investigated the feasibility of using a model built within one species to discriminate the samples from other species. Successive projections algorithm (SPA) was used to select effective wavelengths. The results showed that least squares-support vector machines (LS-SVM) coupled with first derivative preprocessed spectra achieved the best performance for both single and mixed models. Fifteen effective wavelengths, only 0.87% of the full wavelengths, were selected by SPA to build an LS-SVM model, and the sensitivity, specificity and accuracy in validation set were 0.990, 0.954, 97.44%. The results showed that near infrared spectroscopy combined with SPA and LS-SVM can be used to detect surface knots on different coniferous wood varieties. SPA is a powerful tool to select the efficient variables, and it can simplify model and improve model prediction precision.

In order to improve the accuracy of on-line monitoring of ethanol solid-state fermentation process, We carried out the fast quantitative detection of ethanol solid state fermentation process parameters based on Fourier transform near infrared spectroscopy (FT-NIRS). The synergic interval partial least squares (siPLS) method was taken to select the optimal wavelength intervals from the standard normal variate transformation (SNV) preprocessing spectra. Characteristic wavelength variables were extracted from the optimal wavelength intervals by genetic algorithm (GA), competitive adaptive reweighted sampling (CARS) and iteratively retaining informative variables (IRIV). The partial least squares (PLS) forecast model of solid state fermentation process parameters (the level of ethanol and glucose) was established. The characteristic wavelength variables of these parameters were selected by different methods. The results show that compared with GA and CARS methods, IRIV method can select the fewest wavelength variables and the number of characteristic variables associated with ethanol and glucose is 43 and 40, respectively. In IRIV-siPLS model, root mean square error of prediction (RMSEP) is 0.2511 and correlation coefficient of prediction Rp is 0.9934 for ethanol, RMSEP is 0.1730 and Rp is 0.9926 for glucose in prediction set, and the prediction accuracy of the results is also higher than those of other methods. Based on the result, on-line detection of key process parameters in the process of solid-state fermentation is feasible with the near infrared spectral technology. IRIV is an effective method to select characteristic wavelength from the near infrared spectra and improve precision of the prediction model.

The flow-field of dynamic gas lock (DGL) of single-component purge gas is simulated with the type and flux of purge gas and the outgassing rate of dirty gases as variables, and that of multi-component purge gas is also simulated with the volume ratio of mixed purge gases as variable. The simulation results indicate that, for single-component purge gas, the suppression ratio of DGL increases with the increment of gas flux and molecular weight, but has no relation to the outgassing rate of dirty gas. As for the multi-component purge gas, the suppression ratio of DGL approximately remains constant with the increment of volume fraction of the purge gas with large molecular weight. As for the practical application in engineering, it is recommended to use argon-hydrogen mixture as the purge gas in DGL. When the purge gas flux reaches 6.5 Pa·m3·s-1, nearly 25% of the purge gas flows into wafer-stage chamber and the suppression ratio of DGL is more or less 75%. This simulation result provides a basis for the development of DGL in extreme ultraviolet lithography.