Search

In tunable diode laser absorption spectroscopy (TDLAS) tomography, high-resolution images require sufficient projections of absorbed spectral data along line-of-sight laser paths. A reflective TDLAS tomography system was designed to improve the spatial resolved ability of the images, and more than 100 projected laser paths are available in each projection coverage view. In the numerical simulations, the number of projection views and beams per view were evaluated in terms of the image errors of the flame temperature and H2O concentration. The number of projection views and beams per view are optimized for the filtered backprojection (FBP) algorithms, and the proposed reflective TDLAS tomography system yielded a spatial resolution of a grid sizing 1.625 mm. In actual experiments, reconstructed images of different flame distributions in a McKenna burner achieved a high frame rate of 20 frames/s, with a small image error for the flame imaging of temperature and H2O concentration.

Wavelength modulation spectroscopy (WMS) is recognized as a good noise immunity method in tunable diode laser absorption spectroscopy (TDLAS). It can obtain high signal-to-noise ratio harmonic intensity signals for precise gas parameter measurement, such as temperature and concentration. However, the TDLAS-based velocity is sensitive to the Doppler shift in the laser frequency caused by the high-speed flow, which usually requires complex wavelength calibration and precise signal alignment. This work proposed a novel method for the precise velocity measurement directly by extracting the time interval of the even-symmetric 2f/1f harmonics signal with a self-convolution algorithm. The even-symmetric 2f/1f harmonics signal is obtained from the up-and-down laser optical frequency scanning WMS with lock-in amplification technology. A portable measurement system has been developed to achieve simultaneous velocity and temperature measurement of the gas in turbojet engine exhaust with different operation states. The maximum standard deviation of the velocity derived by the proposed method is 15.6 m/s, while that by traditional direct absorption spectroscopy (DAS) and WMS are 69.2 and 26.4 m/s, respectively. Experimental results have verified the improvement of velocity precision by the proposed method. It can provide reliable experimental data for improving the design of combustors and optimizing numerical combustion simulations.

Transient temperature field imaging was realized via lateral shearing interferograms at multiple wavelengths. Three lasers of different wavelengths were coupled to generate a multiwavelength laser. Three phase difference distributions caused by the flame were initially extracted by identifying the centerline of the fringes, followed by three optical path difference distributions. An iterative correction method was introduced to improve the accuracy of the optical path difference. The refractive index image was reconstructed by using the inverse Abel transform, and the temperature image was then retrieved. Numerical simulations were carried out for performance evaluations. Reconstruction errors of optical path difference and optical path distributions caused by the flame were 0.0241 and 0.0293, respectively. Images of refractive index and temperature were retrieved with errors of 0.0465 and 0.0935, respectively. In experiments, interferometric temperatures for a steady flame produced by a Bunsen burner agreed well with the thermocouple readings. Dynamical flame extinguishment was captured at a frame rate of 20k frames/s. Temporal variations of average temperatures at different heights were visualized. The temperature distribution caused by a high-voltage pulsed glow discharging in less than 0.5 ms was also clearly imaged.

A single dual-wavelength comb fiber laser was designed to emit simultaneously two asynchronous ultrashort pulse sequences for gas temperature detection. The interpulse coherence can be easily realized by sharing the same cavity and experiencing the same environment, and complicated feedback control is no longer required. The asynchronous pulses yield an optical sampling for interferogram in the time domain. A heatable cell filled with acetylene and nitrogen was used as the target object. The absorption spectrum of acetylene from 6492.52 to 6496.4 cm-1 was obtained by performing fast Fourier transform (FFT) on the phase-corrected interferograms. The standard deviation (STD) of the residual error between the measured spectra and HITRAN database was within 0.01. A baseline-immune multispectral fitting method for gas absorption estimation was proposed to enable precise temperature calculation. Simulation results demonstrate that compared with two classical methods, i.e., the frequency-domain (FD) multispectral fitting method and time-domain (TD) molecular free-induction decay (mFID) method, the proposed method shows a higher accuracy of gas temperature and concentration measurement and is applicable to various baseline types and noises. In the experiment, compared with the two classical methods, the maximum relative error between the measured and reference temperatures of the proposed method was reduced to 3.2%. Simulation and experiment results verify that the proposed method yields higher accuracy and noise immunity than the two classical methods.

Laser absorption spectroscopy (LAS) tomography is an effective method for cross-sectional imaging of temperature and gas concentration distributions in combustion diagnosis. In this article, the adaptive basis function fitting and artifact removal method is proposed to realize robust imaging in LAS tomography. Modified Mexican hat functions are introduced as basis functions to depict continuous distributions in the region of interest (ROI). Adaptive basis function fitting is realized by introducing a second reconstruction with core parameters of basis functions, the scale factors, and center points, determined adaptively from the first reconstruction. After obtaining the integral absorbance densities of two different spectral lines by adaptive basis function fitting, the similarity between their ratio and one of them is used to locate and remove the artifacts in reconstructed temperature images. The proposed method yields less artifacts and shows stronger noise immunity. The temperature image error can decrease by 12% at high noise levels. Dynamic flames of a McKenna burner were measured and temperature images with less artifacts were achieved. In an acoustically excited Bunsen burner, the proposed method precisely extracted the fundamental frequency and acoustical excitation frequency and yielded a higher structural similarity index. For a high-temperature wind tunnel, the maximum relative error of temperature in the center of the imaging region was 5.43% and the robustness of the proposed method in practical applications was verified.

A planar laser-induced fluorescence (PLIF) using the third harmonic of the neodymium-doped yttrium aluminum garnet (Nd-YAG) laser at 355 nm is employed to visualize temperature and H2O/CH2O concentration distributions inside flames. Laser absorption spectroscopy (LAS) is employed for initial images of temperature and H2O concentration, and the measured absorption offers constraints to update temperature and H2O concentration images. A chemical reaction kinetics model based on ethanol combustion mechanisms is established, offering the production rate of H2O and CH2O, thereby bridging PLIF and LAS. The images of temperature and CH2O/H2O concentration are produced iteratively for quantitative imaging of the flame cross-section. A flame fueled with ethanol vapor was used, and the images of temperature, H2O concentration, and CH2O concentration were given. Compared with thermocouples, the temperature difference was found to be no more than 40 K. The images of H2O and CH2O concentrations detailed the area of incomplete combustion within the flame and its temporal variations. Relative deviations from the experiment results to the ideal values are, respectively, 3.05% and 5.34% for H2O and CH2O.

Tunable diode laser absorption spectroscopy (TDLAS) tomography is widely used for gas temperature and concentration imaging. Laser beam optimization is an efficient way to improve imaging quality with limited available projections for tomography. A beam optimization method independent of any specific distribution was proposed. Asymptotic point spread functions (PSFs) were generated with the Dirac function approximated by Gaussian functions, and the shape proximity between PSF and the Dirac function was estimated. Simultaneous algebraic reconstruction technique (SART) was applied for fan-beam layout optimization. Typical beam optimization methods were compared for numerical verifications. Reconstruction errors of the optimal beam layouts obtained from the proposed method were generally smaller than or equivalent to those from the literature. A TDLAS tomographic sensor with the optimal layout was realized, with only five pairs of distributed feedback (DFB) lasers used for nine projection angles. The flame of a Bunsen burner with a flat nozzle was detected, and beam layouts from the real sensor with projections missing were evaluated for experimental verifications. Averaged deteriorations of image quality indicated by the structural similarity index (SSIM) of temperature and H2O mole fraction were only 0.7% and 1.5%, implying the immunity of missing projections by the optimal beam layout. The SSIM variation with the number of missing projections was also well predicted by the proposed method, which verified the correlation between shape proximity and image quality.

Tunable diode laser absorption spectroscopy (TDLAS) is a popular technique for noncontact temperature measurement but is highly susceptible to beam-steering distortion due to the time-varying along-path inhomogeneity of refractive index in dynamic process monitoring. An adaptive beam-steering-distortion compensation method is proposed to eliminate the distortion in TDLAS measurement. A high-frequency modulated laser at a nonabsorbing wavelength is coupled with a conventional low-frequency scanning laser at an absorbing wavelength and passes through the target field along an identical path. A synchronous demodulation method is proposed to demodulate the transmitted hybrid laser signal into the distorted absorption and distortion signals. The distortion signal is utilized to adaptively compensate the distortion parasitic on the distorted absorption signal. Experimental results obtained on a vibrated water thermostat show that the maximum deviation of temperature derived by the proposed method is 4.97 K, while that by the traditional DAS method is 34.64 K. Experimental results on a turbulent flame show that the relative standard deviation of temperature obtained by the proposed method has decreased from 36.7% (DAS) to 4.20%. Also, the temperature fitting success rate has increased from 88.0% to 100% in the turbulent flame case. The results show that the proposed method is more precise and robust than the traditional method. The proposed method will potentially play an important role in laser-based dynamic combustion monitoring and diagnosis.

A laser absorption spectroscopy (LAS) fused electrical tomography (ET) is introduced to non-invasively measure the admittivity and temperature distributions of Bunsen burner flames. All the operations are carried out at the same region and height at multiple fuel-rich combustion states in the same cross section. The closer the fuel-to-air ratio of the combustion state is to one, the greater the values of admittivity and temperature. Random forest (RF) regression method is used to construct a mapping model for admittivity and combustion state to temperature. The maximum absolute error and relative error between mean temperatures of flame region estimated from reconstructed admittivity distributions and constructed mapping model with those measured by LAS are 60.45 K and 4.8%. The proposed method is used to monitor dynamic acoustically excited Bunsen burner flame, and the flame frequency measured in the spectrums of admittivity and temperature matches the measurements of a visible light photodetector. Experiments demonstrate the ability of ET to monitor the combustion states and temperature distribution of dynamic combustion fields.

Designing a solid-state electrolyte that satisfies the operating requirements of solid-state batteries is key to solid-state battery applications. The consensus is that solid-state electrolytes need to allow fast ion transport, while providing better interfacial compatibility and mechanical tolerance. Herein, a simple but effective strategy is proposed, combining hard and soft component polymer systems, to exploit a solid polymer electrolyte (SPE) with a 3D network via an in situ graft polymerization. The 3D structure is constructed by a hard cellulose nanocrystal (CNC) as the skeleton and a soft polyacrylonitrile (PAN) as the filler through a dry-processing method. The reported systems have several advantages, including ease of processing, only requiring using an exceedingly small amount of solvent, light weight (ρ = 1.2 g cm–3), excellent mechanical stability (tensile strength of 9.5 MPa), and high ionic conductivity (3.9 × 10–4S cm–1, 18 °C) and migration number (tLi+= 0.8). In particular, the high conductivity is enabled: the efficient Li+transportation path constructed between CNC-PAN powders and abundant sulfonate radicals and hydroxyl groups on the CNC surface acts as the bridge of Li+transition. When the CNCs are grafted onto the PAN polymer, the dipole–dipole interaction between the nitrile groups of the PAN and the hydroxyl groups of the CNCs can help to improve the mechanical stability and ionic conductivity of the SPE. Moreover, a tightly formed interface between SPE and LiFePO4(LFP)/carbon black/SPE cathode can be achieved in an assembled solid-state battery by hot pressing, thus further enhancing the battery’s performance.

A single spectral line method for gas temperature as well as concentration extraction was proposed by using iterations with a fuzzy proportional–integral-derivative (PID) controller in tunable diode laser absorption spectroscopy (TDLAS). Usually, two or more spectral lines are essential to extract temperatures from coupled gas concentration and pressure. The proposed method utilized the line shape of a single absorption spectrum to decouple gas parameters along the laser path simultaneously and simplified the optical implementations. Differential equations of the Voigt profile were introduced at multiple wavenumbers to extract gas parameters from a single spectral line. A fuzzy PID controller was utilized to iteratively achieve the single spectral line from widely existed overlapping spectra. A relative temperature error within 2.5% at reference temperatures ranged from 300 to 2300 K was achieved by using the spectral line of $7444.35\,\,{\mathrm {cm}}^{-1}$ from noise free data. At low temperatures below 350 K, the proposed method using the single spectral line of $7181.14\,\,{\mathrm {cm}}^{-1}$ yielded smaller errors in noisy cases, and the temperature errors were verified within 5 °C on the water-based thermostat below 100 °C using the single spectral line. Experiments of axisymmetric counterflow flames at different heights were also implemented. The proposed method effectively reconstructed distributions of flame temperature and water vapor concentration inside, by only using a single spectral line of $7444.35\,\,{\mathrm {cm}}^{-1}$ .

Electrical capacitance tomography (ECT) utilizes mutual capacitances at the boundary of the region of interest for noninvasive and contactless visualization of the distribution within the field, but the low quality of reconstructed image is a major constraint to its application. A $\text {PI}^{\lambda }\text {D}^{\mu }$ -controlled Calderon’s method is proposed by using the sparsity and low rankness of the triple-valued distributions and online tuning ability of the $\text {PI}^{\lambda }\text {D}^{\mu }$ control scheme. The iterations of the method are realized in a closed control loop. The fractional $\text {PI}^{\lambda }\text {D}^{\mu }$ the controller reduces the difference between the measured capacitance matrix and the estimated capacitance matrix derived from the reconstructed distribution. Calderon’s method is fed by the controller output and generates enhanced edges in the reconstructed image via a Sobel–Feldman operator. Also, the smooth segmentation function is then adopted to fuse the triple values known in advance to improve the image quality. Both numerical simulations and experiments demonstrate that the proposed method yields images of well-defined edges and shapes for triple-valued distributions.

Laser absorption spectroscopy (LAS) tomography is an effective combustion diagnosis method for its simultaneous imaging of temperature and gas molar concentration. Only limited projections are available in many applications, the unknowns in the image reconstruction are much more, and it restricts the quality of reconstructed images. The radial basis function (RBF) is introduced to simplify the expressions of continuous distributions in the region of interest (ROI). The number of unknowns is greatly reduced, as gray values in the imaging region are depicted by the coefficient vector of these RBFs. The continuity in temperature distributions was coupled with the simultaneous algebraic reconstruction technique (SART) method. The coefficient vector of these RBFs and density distributions of integral absorbances were obtained. Gaussian compactly supported RBF was selected to reduce computation burden and reconstruction error. Performance comparisons between the proposed method and the classical SART method were made. The imaging quality of the proposed method was superior to SART, the temperature error was smaller than SART by nearly 10% and high spatial resolution was achieved. Dynamic flames in the McKenna burner and wind tunnel were used to verify its robustness and applicability in harsh cases.

3-D objects are illustrated in terms of depth and reflectivity, and these parameters are usually detected by different devices. A modulated single pixel imaging (MSI) method is introduced for simultaneous detections of both depth and reflectivity in 3-D targets. Two modulations for spatial resolution and noise immunity are realized by operations of a digital-micro-mirror device (DMD) and emitted laser amplitude. Laser intensities are modulated at a high frequency up to 100 MHz and demodulated for their amplitude and phase shift. Modulated laser is reflected by the imaged object and collected by a single photodetector. The imaging model is termed as a minimization problem and solved by a proposed modified log-barrier method at optimal iteration steps. The proposed method yields faster convergence and fewer steps of about a half of that used in the typical line-searching method. Two mirrors were positioned in parallel to fabricate a 3-D phantom. The distributions of both depth and surface reflectivity of these mirrors are well reconstructed. Both simulated and experiment data verified the efficacy of proposed MSI on 3-D objects.

A parameter fitting-based fast imaging method for axisymmetric flame temperature field was proposed in a lateral shearing interferometer. In the extinction state, a sawtooth waveform was used to modulate a distributed feedback (DFB) laser to obtain the quantitative mapping from modulated voltage to phase. In the combustion state, the laser was rapidly driven by an irregular waveform of five steps. Linear equations were established, and the phase difference caused by the flame at each pixel was extracted by parameter fitting. Flame phase distribution was obtained to image refractive indexes and temperatures. Compared with the existing waveform fitting-based wavelength modulation for flame monitoring, the proposed method reduced the modulation steps to five and improved the imaging speed up to eight times. In numerical simulations, an axisymmetric counterflow flame was reconstructed to evaluate the performance of the proposed method. Reconstruction errors of phase difference, refractive index, and temperature distributions were 0.0117, 0.0692, and 0.0795, respectively. In experiments, three counterflow flames of different flow conditions were imaged. The flame structures were clearly visualized, and the interferometric temperatures matched well with the readings of a thermocouple. A Bunsen-type flame with 100-Hz acoustic excitation was monitored at 8 kHz. The variation of the temperature distributions well reflected the flame oscillations. The frequencies of fundamental, second, and third harmonics were captured, and the harmonic at 99.43 Hz caused by the acoustic excitation was also precisely identified.

Tunable diode laser absorption spectroscopy (TDLAS) techniques usually utilize direct absorption spectroscopy (DAS) to measure absorbance profiles for temperature measurements. The DAS method is sensitive to thermal noises and fails to work in harsh application cases. A noise-immune method is proposed for robust temperature measurement by using coherent detection and retroflected optical alignment. The absorption spectrum is shifted to a high-frequency band of MHz level away from ambient noises. The optical alignment suppresses thermal radiations along the laser path. Gas temperatures were measured in cases of both laboratory and porotype setup of aeroengine, i.e., the steady and the harsh states. Transition lines of H2O at 7182.94, 7185.59, and 7444.35 cm−1 were selected for performance evaluations of target molecules, i.e., of water vapor. Performance comparisons were made with the DAS method for temperature detection. In a steady-state case, standard deviations of the proposed method were below 0.9 K at SNR of 25 dB, while those of the DAS method were above 3.9 K. In an onsite harsh application case, the fluctuations of path-averaged temperatures obtained by the proposed method were also smaller. The coherent detection and retroflected alignment enable better performance in hostile cases.

Precise and bias-immune absorption spectrum was directly extracted from wavelength-modulated intensities for dynamic gas temperatures by a proposed novel downsampling scheme. Absorbed wavelength-modulated laser intensity generated multiple direct absorption profiles by downsampling at equal phases in each modulation cycle. The number of achieved profiles equals that of sampled intensities in each wavelength modulation cycle. All these profiles are employed to remove intensity biases from thermal radiations and obtain an entire absorption spectrum of target gases. A water-based thermostat was used to evaluate the noise reduction of the proposed method in controlled noisy cases. Deviations of achieved gas temperatures are less than 4 °C, and precision is quantitated by signal-to-noise (SNR) values that are achieved by the proposed method are respectively 15 and 5 dB higher than those of direct absorption spectroscopy (DAS) and wavelength modulation spectroscopy (WMS) methods. Dynamic temperatures measured by the proposed method are used to evaluate temporal variations of an acoustically excited flame. It identified the sinusoidal temperature variation, and its harmonic strength at the target frequency is 1.5 times stronger than that of the direct absorption spectrum method in noisy cases, e.g., SNR from 40 to 60 dB. The intensity bias from the thermal radiation is also derived by the proposed method, and the bias value agrees well with that of the reference detector for radiative variations of a correlation coefficient of 0.98. Both simulated and experiment results verified the robust performance of the proposed method for flame temperatures with strong thermal radiation and noises.

A planar laser-induced fluorescence (PLIF) of a single wavelength is introduced to image temperature and concentration distribution inside flames. Laser absorption spectroscopy (LAS) tomography was used to provide initial images of gas temperature for image iteration. The images of temperature and concentration are used to update the fluorescence image. The fluorescence images are also corrected to update images of temperature and radical concentrations iteratively. The intensity attenuation losses due to absorption in PLIF is corrected in the iterations. Single wavelength PLIF and LAS tomography are simultaneously performed, and fluorescence image at a single wavelength is required only for each quantitative measurement. The proposed method has a twice higher speed than the classical dual wavelength PLIF. In numerical simulations, the relative error of reconstructed images of temperature is within 7% and that of the concentration is less than 3% with a signal-to-noise ratio (SNR) higher than 30 dB. Experiments were conducted on a McKenna burner, quantitative images of temperature and OH concentration were obtained and compared with computational fluid dynamics (CFDs), thermocouple, and two-color PLIF. The absolute errors are less than 30 K in the center of the burner. The relative errors of concentration are less than 7% in the flat flames.

A discrete tomographic imaging method is introduced to reconstruct distributions of temperature and gas molar concentration in tunable diode laser absorption spectroscopy (TDLAS). The proposed method uses projection histograms along laser paths from different projecting angles. Continuously distributed temperature and specific gaseous concentration in the combustion region of interest are discretized into two finite sets of value pairs in the feasible ranges of temperature and gas concentration, and in this way, these two distributions are well approximated by the value discretization. The Voigt model between absorption spectral profiles and gas temperature, as well as concentration, is simplified to a linear matrix equation, and its binary-valued solution yields values of temperature and gaseous concentration from these two finite sets. These sets are composed of discrete value pairs of the gas temperature and molar concentration. The projection histogram along each laser path is determined by the coefficients of the gas temperature and concentrations from the measured line-of-sight absorption spectrum. From projection histograms along various laser paths, cross-sectional distributions of temperature and concentration are simultaneously obtained from the combinations of distributions of optimally selected discrete pairs. Numerical simulations are conducted to evaluate the proposed discrete tomography method, and relative errors of temperature and concentration are reduced by more than 30% compared with the classical two-color method, especially in noisy cases. A McKenna burner at different airflow rates and Bunsen flames with acoustical excitations are applied to verify the proposed method in stable and dynamical flames. Both simulated and experimental results show that the proposed method generates better images and noise-immune performance.

Although SiOx/graphite (SiOx/Gr) composite anodes are commercially applied to a certain extent, there are still some unsolved challenges, such as a large volume expansion during the lithiation/delithiation process, rapid performance attenuation at a high temperature, etc. In this work, we systematically discuss the effect of a fluoroethylene carbonate (FEC) additive on the SiOx/Gr anode-based pouch cells and make an in-depth attenuation mechanism analysis at a high temperature. Experimental results show that FEC can accelerate the generation of gas and HF after 60 °C storage, which will cause cathodic corrosion. Moreover, the loss of active Li and the failure of the electrode structure are two main factors resulting in performance degradation of SiOx/Gr||NCM811 pouch cells at a high temperature.

A solid electrolyte interphase (SEI) layer on a graphite anode plays a crucial role in deciding electrochemical properties of the electrode including the first Coulombic efficiency, rate capability, operating temperature, and long-term cycling stability. However, the ultrathin functional SEI layer is always naturally grown via electrolyte reduction decomposition reactions. Herein, we report a new strategy of in situ transformed solid electrolyte interphase of high stability by implanting a 4-vinylbenzoic acid (4-VBA) nanolayer on a mildly oxidized graphite surface. A 4-VBA layer of 40 nm contributes to the transformation of a robust and stable SEI layer, which not only significantly enhances the overall electrochemical performances of the natural graphite electrode but also greatly prolongs the cycle life of the full cell with the LiNi0.6Co0.2Mn0.2O2cathode. The effectively suppressed surface evolution aroused from the stable organic SEI transformed from the implanted 4-VBA nanolayer explains the enhanced electrochemical properties.

Random vibrations were employed to pick up each monochromatic component in a continuous-wave cavity ringdown spectroscopy (CRDS) system using a bichromatic laser source. Light frequencies were selected within flat portions of an absorption profile to suppress the jitter in laser frequency during measurements. An interference effect caused by cavity length variations was suppressed by optimizing the initial fit point for each ringdown transient. The difference in exponential decay rates of two frequencies determined the gas mole fraction, and no calibration of empty cavity losses was necessary. Experiments on varying humidity were conducted, and the results agreed with the readings of a commercial hygrometer.

We propose a method to reconstruct the two-dimensional (2D) velocity distribution of flow fields by laser absorption spectroscopy tomography. A mathematic model is established to reveal the dependence of spectral absorbance on line-of-sight velocity distribution. Then, with multiple laser beams from different angular views covering the region of interest, a nonlinear equation set of 2D velocity distribution is established according to the model. The integrated absorbance coefficient distribution is reconstructed using the Landweber iteration algorithm and substituted into the nonlinear equation set for further simplification. Finally, the velocity distribution is reconstructed by solving the simplified equation group via the interior point algorithm. The proposed method is validated numerically by reconstructing the velocity distribution of water molecules, as calculated by computational fluid dynamics, over a cross section of a double-mode scramjet combustor. The method does not require adding extra tracer particles and avoids issues arising from the short lifetime of molecular tags. It is suitable for diagnosis of high-speed flow fields.

Lipolysis-stimulated lipoprotein receptor (LSR) is a multi-functional protein that is best known for its roles in assembly of epithelial tricellular tight junctions and hepatic clearance of lipoproteins. Here, we investigated whether LSR contributes to intestinal epithelium homeostasis and pathogenesis of intestinal disease. By using multiple conditional deletion mouse models and ex vivocultured organoids, we find that LSR elimination in intestinal stem cells results in the disappearance of Paneth cells without affecting the differentiation of other cell lineages. Mechanistic studies reveal that LSR deficiency increases abundance of YAP by modulating its phosphorylation and proteasomal degradation. Using gain- and loss-of-function studies, we show that LSR protects against necrotizing enterocolitis through enhancement of Paneth cell differentiation in small-intestinal epithelium. Thus, this study identifies LSR as an upstream negative regulator of YAP activity, an essential factor for Paneth cell differentiation, and a potential therapeutic target for necrotizing enterocolitis.

In this paper, a digital micro-mirror device (DMD)-based detector is proposed for the detection of light intensity in particle-sizing instruments using Fraunhofer diffraction. The detector consists of only one photodiode, which eliminates the distortions caused by the nonuniformity of the detector arrays used in traditional instruments. The center of the diffraction pattern was accurately located to distribute the optimized arc-shaped mirror arrays for the intensity detection. Both simulated and experimental results showed that the proposed detector was superior to the classical one as it was less sensitive to noise than the detector arrays used in traditional systems.

In this paper, a robust modified Landweber algorithm was proposed to retrieve the particle size distributions from Fraunhofer diffraction. Three typical particle size distributions, i.e., Rosin–Rammler, lognormal, and bimodal normal distributions for particles ranging from 4.8 to 96 μm, were employed to verify the performance of the algorithm. To show its merits, the proposed algorithm was compared with the Tikhonov regularization algorithm and the ℓ_1-norm-based algorithm. Simulation results showed that, for noise-free data, both the modified Landweber algorithm and the ℓ_1-norm-based algorithm were better than the Tikhonov regularization algorithm in terms of accuracy. When the data was noise-contaminated, the modified Landweber algorithm was superior to the other two algorithms in both accuracy and speed. An experimental setup was also established and the results validated the feasibility and effectiveness of the proposed method.

Rational design and construction of stable artificial interface for silicon (Si) anodes exhibits great promise in shielding the Si particles against their intrinsic volumetric changes and minimizing the side reactions, both constituting prerequisites towards the long-term stability of the high-energy density Si-based batteries. Herein, a multifunctional solid-electrolyte interphase (SEI) precursor of 4-trifluoromethylphenylboronic acid (TFPBA) nano-layer is tailored, which readily polymerizes to form 2,4,6-tris-4-(trifluoromethylphenyl)boroxine (TTFPB) on Si surface during high-temperature drying process of the electrodes. After one-electron reduction, the BO bonds in TTFPB molecule break where the radical molecules are thus generated, initiating the spontaneous polymerization to form the poly-4-trifluoromethylphenylboronic acid (PTFPBA) with repeated B–O chains. Such polymerized nano-layer not only manifests a desirable artificial SEI for its high robustness and elasticity in accommodating the volume expansions, but also effectively improves the electrolyte absorption rate of the electrode, providing accelerated kinetics for Li+transfer. Under the stable framework formed by PTFPBA, preferential adsorption of LiPF6molecules is enabled with the electron-deficient boron (B) species, further inducing a continuous and dense SEI rich in benzene rings and inorganic substances. As such, the as-obtained Si@TTFPB anode demonstrates significantly enhanced rate capability and long-cycle performance. After 500 cycles at 0.2 C rate, the modified Si electrode still delivers a capacity of 1778.7 mA h g−1, while the reference Si anode has almost no capacity.

Electrokinetic remediation is in-situ remediation technique. Potassium dichromate was chosen as the pollutant and its initial concentration was 500mg·kg-1 in Kaolin soil. This experiment, we are to study the feasibility ,the factors which influence the whole course, including applied voltage, treatment time, soil moisture, OH- produced at the cathode and its control. It indicate that, there is separating out oxygen at anode, hydry at cathode. Cr2O72-and CrO42- absorb electron to change to Cr3+, and unite to Cr (OH)3. The experiment results show OH- produced at the cathode has crucial effects on the removal efficiency of chromium; secondly the applied voltage and treatment time have important influence on the efficiency, and the soil moisture affects the efficiency in some degree.

Regularization methods were combined with line-of-sight tunable diode laser absorption spectroscopy (TDLAS) to measure nonuniform temperature and concentration distributions along the laser path when a priori information of the temperature distribution tendency is available. Relying on measurements of 12 absorption transitions of water vapor from 1300 to 1350 nm, the nonuniform temperature and concentration distributions were retrieved by making the use of nonlinear and linear regularization methods, respectively. To examine the effectiveness of regularization methods, a simulated annealing algorithm for nonlinear regularization was implemented to reconstruct the temperature distribution, while three linear regularization methods, namely truncated singular value decomposition, Tikhonov regularization, and a revised Tikhonov regularization method, were implemented to retrieve the concentration distribution. The results show that regularization methods not only can be used to retrieve temperature and concentration distributions closer to the original but also are less sensitive to measurement noise. When no sufficient optical access is available for TDLAS tomography, the methods proposed in the paper can be used to obtain more details of the combustion field with higher accuracy and robustness, which are expected to play a more important role in combustion diagnosis.

Autogenous shrinkage is an important factor for cracking of cement-based materials at early ages. This review summarizes different definitions and testing methods for autogenous shrinkage in literature. Autogenous shrinkage should be defined as the sum of chemical shrinkage and self-desiccation shrinkage. All testing methods in the literature can be divided into two categories: direct and indirect testing methods. Direct testing methods usually measure volumetric or linear dimensional changes. Indirect methods usually measure porosity or change in relative humidity of cement-based materials, which can reflect the change in autogenous shrinkage. Indirect methods need to establish correlations between autogenous shrinkage and porosity or relative humidity.

Based on the principle of ENV 196-4 “Methods of testing cement – Part 4: Quantitative determination of constituents” or Chinese Standard GB/12960-2007 “quantitative measurement of mineral admixtures in cement”, a method was developed for quantitative determination of fly ash (FA) in fresh cement mortars and concretes. The effects of several factors, such as residue content of FA on an 80-μm sieve, silt content of aggregates, water-reducing agent, and hydration time on the measurement were studied. Experimental results indicated that during the first 3 h, the hydration time did not show an effect on measured results, but the residues of FA on an 80-μm sieve and silt contents of aggregates demonstrated significant effects on the measured results. The results obtained from the developed method were very close to the actual contents after the consideration of the residue content of FA and silt content of aggregates. Therefore, the method developed can be effective for quality control and analysis of fresh concrete.

Water resources is the important strategic resources, and how to realize the sustainable is the world's theme, is the foundation of human survival. The purpose of this study is: useing building wastewater as the research object, using MBR (membrane bioreactor) technology as the sewage processing.Through the analysis on the actual case,put forward the reclaimed water process and operation cost accounting.It appears that the costs of water reuse is 0.83 yuan per ton, is in a very low level. The technology is in the actual water reuse processing, and have the reality significance.

Feathers, as a waste, are produced in large quantities from poultry processing industry every year. In this paper, feathers were biodegraded by Stenotrophomonas maltophilia DHHJ which was isolated from soil samples. The results show that the optimal conditions for the feather degradation and the keratinase production are 2.5% feather as substrate, the initial pH of 7.8 and cultivation at 40 ℃ for 5 days. Salts, KCl and NaCl, can increase feather degradation slightly. The proper concentration of Tween 80 can enhance keratinase production significantly. EDTA, as a metalloprotease inhibitor, greatly inhibits keratinolytic activity.

Abstract: Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is expressed on epithelial cells throughout the intestinal tract and is a negative regulator of tumor cell growth, suggesting that it may function as a tumor suppressor. In this study, to determine whether the CEACAM1 is involved in colorectal tumorigenesis, we have investigated the genetic alterations, including mutations and allelic loss, of the CEACAM1 gene in 17 colonic adenomas and 123 sporadic colorectal cancers. In addition, the expression pattern of the CEACAM1 protein was examined in 60 colonic adenomas and 123 sporadic colorectal adenocarcinomas. No mutation was found in colonic adenomas, but four somatic missense mutations, L36F, T312I, V398I and A445V, were detected in colorectal cancers. Interestingly, all of the mutations were found in left-side colon cancers of the patients with clinical stage III. In LOH analysis, nine adenomas were informative for at least one of the markers and five (55.6%) showed allelic loss. Thirty-eight cancers were informative at D19S211 and D19S872 markers and 21 (56.3%) showed LOH at these markers. Statistically, the frequency of allelic loss at the CEACAM1 locus was not associated with clinicopathologic parameters (P > 0.05). In immunohistochemical analysis, loss of expression of CEACAM1 protein was detected in nine (15.0%) and 30 (24.4%) of 60 colorectal adenomas and 123 colorectal cancers. Statistically, there was no significant relationship between loss of CEACAM1 expression and clinicopathologic parameters, including clinical stage, tumor location, tumor size, lymph node metastasis and 5-year survival (P > 0.05). These data suggest that genetic alteration and loss of expression of the CEACAM1 may contribute to the development of colorectal cancers, as an early event.

A new solution to the inversion of Fraunhofer diffraction for particle sizing was introduced. Compared with the well-known Chin-Shifrin inversion, it is an inversion of the form of integral transform and less sensitive to noise. Simulation results with noise-contaminated data were obtained and showed that the new inversion is better than the Chin-Shifrin inversion. Especially when the particle diameter was small, the new inversion still performed well, whereas the Chin-Shifrin inversion did not converge.