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Segmentation is an essential part in SAR image analysis and application. However, the presence of speckle noise and intensity inhomogeneity regions leads to great difficulty in SAR image segmentation. In this letter, we propose a novel level set method that integrates the local intensity and the global feature information for better segmentation results. To establish the energy function, a new image model is developed to describe the inhomogeneous SAR images and form the local intensity clustering term. Meanwhile, the feature map extracted by invariant moment is used to define the global fitting term through a piecewise constant function. Segmentation is realized by solving the level set function from the minimization of the energy function. Experiments on the synthetic and real SAR images verify the effectiveness of the proposed method.

Al-based composites reinforced by high volume fraction ceramic particles have attracted much attention because of their high specific strength, high specific modulus, good wear resistance, and low thermal expansion properties. The preparation technology, advantages, and disadvantages of Al-based composites reinforced by high ceramic content are reviewed in this study. The research status of the microstructure and mechanical properties of Al-based composites reinforced by high ceramic particles content is summarized. The effects of ceramic content and preparation technology on the properties of Al-based composites are described. The strengthening mechanism of micro-nano-scale ceramic particles in composites is also expounded. The development trend of micro-nano-scale high content ceramic particle-reinforced Al-based composites is prospected.

The sensory responses of cortical neuronal populations following training have been extensively studied. However, the spike firing properties of individual cortical neurons following training remain unknown. Here, we have combined two-photon Ca2+ imaging and single-cell electrophysiology in awake behaving mice following auditory associative training. We find a sparse set (~5%) of layer 2/3 neurons in the primary auditory cortex, each of which reliably exhibits high-rate prolonged burst firing responses to the trained sound. Such bursts are largely absent in the auditory cortex of untrained mice. Strikingly, in mice trained with different multitone chords, we discover distinct subsets of neurons that exhibit bursting responses specifically to a chord but neither to any constituent tone nor to the other chord. Thus, our results demonstrate an integrated representation of learned complex sounds in a small subset of cortical neurons., Using a combination of two-photon imaging and single-cell electrophysiology, the authors discover that associative learning induces the emergence of a unique subset of neurons in the auditory cortex, exhibiting high-rate bursting responses to the learned complex sounds but not to any of the constituents.

As an active microwave remote sensing device, synthetic aperture radar (SAR) has been widely used in the field of marine surveillance. However, moving ships appear defocused in SAR images, which seriously affects the classification and identification of ships. Considering the three-dimensional (3-D) rotational motions (roll, pitch, and yaw) of the navigating ship, a novel method for refocusing moving ships in SAR images based on inverse synthetic aperture radar (ISAR) technique is proposed. First, a rectangular window is used to extract the defocused ship subimage. Next, the subimage is transformed into the ISAR equivalent echo domain, and the range migration and phase error caused by the identical movement of all ship scatterers are compensated. Then, the optimal imaging time can be selected by the maximum image contrast search method. Finally, the iterative adaptive approach (IAA) is used to obtain the image with high resolution. This method has satisfactory imaging performance in both azimuth resolution and image focus, and the amount of calculation is small due to the processing of subimages. Simulated data and Gaofen-3 real SAR data are used to verify the effectiveness of the proposed method.

Hyperspectral LiDAR (HSL) is a new remote sensing detection method with high spatial and spectral information detection ability. In the process of laser scanning, the laser echo intensity is affected by many factors. Therefore, it is necessary to calibrate the backscatter intensity data of HSL. Laser incidence angle is one of the important factors that affect the backscatter intensity of the target. This paper studied the radiometric calibration method of incidence angle effect for HSL. The reflectance of natural surfaces can be simulated as a combination of specular reflection and diffuse reflection. The linear combination of the Lambertian model and Beckmann model provides a comprehensive theory that can be applied to various surface conditions, from glossy to rough surfaces. Therefore, an adaptive threshold radiometric calibration method (Lambertian-Beckmann model) is proposed to solve the problem caused by the incident angle effect. The relationship between backscatter intensity and incident angle of HSL is studied by combining theory with experiments, and the model successfully quantifies the difference between diffuse and specular reflectance coefficients. Compared with the Lambertian model, the proposed model has higher calibration accuracy, and the average improvement rate to the samples in this study was 22.67%. Compared with the results before calibration with the incidence angle of less than 70 degrees, the average improvement rate of the Lambertian-Beckmann model was 62.26%. Moreover, we also found that the green leaves have an obvious specular reflection effect near 650-720 nm, which might be related to the inner microstructure of chlorophyll. The Lambertian-Beckmann model was more helpful to the calibration of leaves in the visible wavelength range. This is a meaningful and a breakthrough exploration for HSL.

Road network is an important part of modern transportation. For the demands of accurate road information in practical applications such as urban planning and disaster assessment, we propose a multiscale method to extract road network from high-resolution synthetic aperture radar (SAR) images, which consists of three stages: potential road area segmentation, preliminary network generation, and road network refinement. Multiscale analysis is implemented using an image pyramid framework together with a fixed-size filter. First, a directional road detector is designed to highlight road targets in feature response maps. Subsequently, adaptive fusion is performed independently at each image scale, followed by a threshold method to produce potential road maps. Then, binary maps are decomposed according to the obtained direction information. For each connected component (CC), quality evaluation is conducted to further distinguish road segments and polynomial curve fitting is adopted as a thinning method. Multiscale information fusion is realized through the weighted sum of road curves. Finally, tensor voting and spatial regularization are employed to generate the final road network. Experiments on three TerraSAR images demonstrate the effectiveness of the proposed algorithm to extract road network completely and correctly.

Multibranched gold nanoparticles (M-AuNPs) can serve as photothermal agents for near-infrared (NIR) photothermal therapy (PTT) of cancer, but a major shortcoming is that they tend to strongly scatter NIR light, causing a significant reduction in absorption. This work addresses this issue, based on theoretical simulations and experimental determinations, to enhance the absorption and reduce the scattering of these materials by screening their structural parameters. Our finite-difference time-domain simulations predict that M-AuNPs with a core size of ∼25 nm, a tip number of 5, and a tip height of ∼40 nm (i.e., an aspect ratio of ∼2) are optimal for trapping NIR light and yielding the highest light-to-heat conversion efficiency (η) and for trapping NIR light of various polarization and incident directions. The predicted M-AuNPs were synthesized by a seed-mediated growth method, and the measured optical properties agreed well with the simulation results. The M-AuNPs were further used as photothermal agents f...

A two-medium solar collector was designed to supply hot water or air to a building, either separately or simultaneously. Its design was based on that of a ceramic collector. The heat efficiency of the two-medium collector was experimentally determined. The design of the collector intended for use in residential buildings was studied. A two-medium collector was designed for a congregated dwelling, which is a priority to determine the heat collector area for the amount of hot water required. For an area 2 , the preheated fresh air from a 1.47 m 2 collector meets the air volume regulation standard. If not, the collector quantity or area can be increased (conditions permitting). For small areas, preheated fresh air of a higher temperature is provided by the collector, thereby increasing energy conservation and user comfort. The integration of the collector with the residence allows it to function in all seasons, by supplementing the heat supplied by conventional heating and meeting the health needs through ventilation.

The kindergartens, characterized by large scale and daytime usage, possess evident typicality and necessity for the application of low cost solar energy. As the main learning place for school-age children, the indoor air quality of kindergarten has significant influence on children’s physical health. To verify the effects of a new flat plate solar air collector system (SACS) with metallic heating panels on the improvement of indoor living environment in kindergarten buildings, the indoor temperature, humidity and air quality in kindergarten were tested and investigated in this paper. Two indoor activity units with the same conditions in kindergarten of Shandong Jianzhu University, were selected as the test rooms. The working conditions of solar air collector in these two test rooms were taken as the reference variable. The systematic monitoring and analysis of air quality parameters such as temperature, humidity and carbon dioxide concentration in 12 reasonably distributed sampling positions were carried out during the continuous five days. The results show that the SACS possesses evident auxiliary heating function for indoor air. The maximum value of the average temperature raise nearly reaches 15%. The preheated air near the air outlet exhibits 10°C higher temperature than outdoor air. Besides, the system leads to slightly lower indoor humidity. In addition, the value of indoor CO 2 concentration significantly decreases up to 800 ppm due to the filtration of the system. Instead of air conditioning to a certain extent during transition seasons, this system can effectively reduce the building energy consumption. It can provide children a more healthy and comfortable indoor air environment through the effective use of green solar energy. The research results in this paper can provide important reference for the wide application of solar air collector system in the special building environment of kindergartens.

As the construction of infrastructures becomes increasingly complex, it has often been challenged by construction delay with enormous losses. The delivery of complex infrastructures provide...

The vanadium-titanium black ceramic (VTBC) coating on all-ceramic solar collectors has both high absorptance (0.94) and high emissivity (90%). However, the thermal conductivity of ceramic is very low (1.256 W/mK). To improve the heat collection efficiency of VTBC solar collectors, this paper establishes a mathematical model based on the energy-conservation relationships under steady-state conditions and creates a corresponding computer program. Key parameters for VTBC solar collectors include the heat-removal factor, effective transmittance-absorptance product for the absorber, total heat loss coefficient, etc. Then, via experimental testing, this study proposes a reference model for domestic VTBC solar collectors in a cold location (η = 0.89 − 2.20Tm*). Last, this work analyzes the influences of fin design and transparent cover design on VTBC solar collectors individually, using the created computer program. Results show that the most effective optimization method is to increase the transmittance of the transparent cover. By increasing the transmittance from 0.93 to 0.96, this study creates an optimized VTBC solar collector theoretical model (η = 0.92 − 2.20Tm*).

This letter proposes a new semantic segmentation network called IGFUnet to map the urban areas from large scale SAR images. The network is based on U-net structure which is especially suitable for semantic segmentation of small data set. Inception module is adopted as the encoder to extract rich and dense features. We develop a global feature attention module (GFA) as a channel attention module to perform feature correction on each decoding layer. Combing the inception module and GFA module can take full use of the feature map and efficiently integrate features from different scales. Qualitative and quantitative experiments based on Sentinel-1A have proved the effectiveness of our IGFUnet model.

It is very attractive to explore topological physics beyond three-dimensional space. This work experimentally demonstrates the realization of a classical analog of higher order/dimensional topological phases in electric circuits. Multiple robust corner states have been observed. These result from the nontrivial hexadecapole moment and may have potential applications in the field of topological analog signal processing with multiple channels. The authors expect that experimental access to higher order/dimensional topological physics with electric circuits can provide a valuable reference for investigating the higher-dimensional topological phase in full real space.

In transition to “Industry 4.0”, the integration capability of innovation resource is a key motivation for the technical progress of manufacturing enterprises. A statistical analysis of the innovation status of manufacturing enterprises in Guangdong province reveals that local enterprises have been increasing in the internal R&D investment, scientific research outputs, and connection strength with international markets. However, the bottlenecks of innovation are also prominent, such as insufficient foreign technology introduction, low levels of innovation internationalization and inadequate overseas cooperative patents for inventions. In the context of global open innovation, some implications are proposed to promote the deep integration of enterprises into the global innovation chain to improve innovation capabilities and transformation and upgrading of manufacturing industry.

Estimating directions of arrival (DOA) without knowledge of the source number is regarded as a challenging task, particularly when coherence among sources exists. Researchers have trained deep learning (DL)-based models to attack the problem of DOA estimation. However, existing DL-based methods for coherent sources do not adapt to variable source numbers or require signal independence. Herein, we put forward a new framework combining parallel DOA estimators with Toeplitz matrix reconstruction to address the problem. Each estimator is constructed by connecting a multi-label classifier to a spatial filter, which is based on convolutional-recurrent neural networks. Spatial filters divide the angle domain into several sectors, so that the following classifiers can extract the arrival directions. Assisted with Toeplitz-based method for source-number determination, pseudo or missed angles classified by the estimators will be reduced. Then, the spatial spectrum can be more accurately recovered. In addition, the proposed method is data-driven, so it is naturally immune to signal coherence. Simulation results demonstrate the predominance of the proposed method and show that the trained model is robust to imperfect circumstances such as limited snapshots, colored Gaussian noise, and array imperfections.

Water area segmentation is an important problem in SAR image comprehension and interpretation. This paper presents an improved region merging approach for SAR complex water area segmentation. First, a new regional similarity criterion is defined based on the gray distance, structure distance and shape distance. The edge response intensity graph and direction graph with the maximum discriminability are used as the structural feature. Geometric constraint is added into the distance criterion as shape distance. Then, the minimum spanning tree (MST) algorithm is used for region merging. The method proposed in this paper does not need complex parameter estimation. Experiments on Sentinel-1A (S-1A) images verify the effectiveness of the proposed method.

Organic sulfur functional groups in coal not only have certain oxidation characteristics at low temperature and but also can break to produce free radicals, which is bound to have a considerable effect on coal spontaneous combustion. However, this area has not been reported yet. There are relatively few studies on variation laws of organic sulfur functional groups in coal in the coal spontaneous combustion process (especially low-temperature oxidation stage), and the release of SO2, the gaseous product of organic sulfur during the low-temperature oxidation, is also rarely reported. Therefore, it is necessary to systematically obtain the change laws of organic sulfur forms in coal during low-temperature oxidation. In this paper, the morphological changes of organic sulfur in coal during low-temperature oxidation were studied first, and then the changes of organic sulfur forms in coal before and after low-temperature oxidation and the release of the low-temperature oxidation product SO2 were studied by using the X-ray photon spectroscopy (XPS) technique and the XLZ-1090 infrared gas analyzer. The XPS analysis results show that the relative contents of mercaptan and sulfide are reduced; the content of thiophene sulfur decreases slightly or remains unchanged; and the contents of sulfone, sulfonate and sulfate all increase. This verifies that the low-temperature oxidation process of active organic sulfur functional groups in coal is: sulfide → sulfoxide → sulfone, mercaptan → disulphide → sulfoxide → sulfone → sulfonic acid. The study reveals that the release of gaseous SO2 is not detected during the low-temperature oxidation of the raw coal samples, whereas it is detected during the low-temperature oxidation of the acid-treated coal samples. This is because the acid treatment can remove alkaline minerals in coal, weakens the inhibitory effect of alkaline minerals on SO2 and enable SO2 to escape almost completely. In addition, the study also discovers that the time and amount of SO2 gas release during the low-temperature oxidation process are directly related to the metamorphic degree and organic sulfur content of coal.

In this study, interactions between free radicals during co-pyrolysis of lignite and biomass were explored. Changes in free radical concentrations were investigated using electron spin resonance (ESR). Additionally, the interactions between free radicals during co-pyrolysis were analyzed based on free radical concentration, thermogravimetric (TG) behavior, and changes in yields and properties of pyrolysis products in a fixed-bed reactor. The results of ESR and TG analyses indicate that, during co-pyrolysis, the combination of radicals, especially that of stable and volatile free radicals, leads to a decrease in both radical concentration and mass loss. The main temperature range for the interaction of free radicals was ~ 380–600 °C. The co-pyrolysis results from the fixed-bed reactor show that the yields of products such as gas, tar, and char are higher than their calculated values, except for water, which confirms the existence of synergy between the coal and biomass. As the resistance of the volatile free radicals escaping from the bed increases, the secondary reactions of volatiles increase during co-pyrolysis, which leads to changes in the composition and properties of gas and tar.

Functional poly(amino acid)s such as poly(e-lysine) have many potential high-value applications. However, the effective chemosynthetic strategy for these materials remains a big challenge in polymer chemistry; the key issue is how to design and protect amino groups for the effective ring-opening polymerization (ROP). Our lab succeeded in chemosynthesis of poly(e-lysine) via delicate design of a 2,5-dimethylpyrrole protecting group and metal-catalyzed ROP processes, but harsh reaction conditions (e.g., ca. 260 °C) were required. Herein, we developed a superbase t-BuP4-catalyzed ROP of e-lactam derivatives, affording high molecular weight poly(e-lysine) bearing pendant protected amino groups with high monomer conversion (up to 95%). The organocatalytic polymerization could proceed at low reaction temperature (e.g., 60 °C) compatible with readily removable protecting groups, providing a sustainable and new methodology toward facile preparation of poly(e-lysine).

The composition and structure of organic sulfur in coal are rather complicated. Thus, no workable method has been adopted to accurately and quantitatively study organic sulfur in coal so far. Coal spontaneous combustion (CSC) is a severe disaster occurring widely in coal industry. It is an extremely complex physical and chemical process as well as a major scientific and technical problem that has always puzzled researchers. Studying the complex chemical reaction of coal by model compounds is a reasonable method extensively recognized and used in the international coal chemistry research field. Model compounds represent certain kinds of specific functional groups in coal. Through an investigation on the reaction mechanism of model compounds, the complex mechanism of coal molecules can be revealed. In this study, in order to better investigate the mechanism of organic sulfur during CSC, representative organic sulfur model compounds containing different organic sulfur functional groups were selected for the low-temperature oxidation experiment and the thermal analysis. Their oxygen consumption amounts and oxidized products concentrations were determined by gas chromatography and infrared analyzer. Besides, the weights and endothermic/exothermic rates of these model compounds during low-temperature oxidation were measured using the thermogravimetry/differential scanning calorimetry (TG/DSC) method. In this way, their oxidative and thermodynamic characteristics were revealed. On this basis, the organic sulfur model compounds were uniformly mixed with the coal samples for the low-temperature oxidation experiment in the hope of exploring its effect on oxygen consumption amounts and indicative gas products during CSC. Finally, the mechanism of the interactions between organic sulfur and other reactive groups in coal during low-temperature oxidization were obtained.

Solvent extraction of coals has been practiced extensively for various purposes including the determination of coal structure. It is generally assumed that the extraction is mainly a physical process involving little change in covalent bonds. But different opinions were reported. This work studies the behavior of radicals during extraction of 3 low rank bituminous coals using 5 solvents, including hexane, toluene, tetrahydrofuran (THF), 1,2,3,4-tetrahydronaphthalene (THN), and N-methyl-2-pyrrolidinone (NMP), using electron spin resonance (ESR). The extractions are carried out at temperatures from the ambient temperature to temperatures somewhat higher than the boiling points of the solvents, as well as under ultrasound. It is found that the radical concentration of the coals changes during the extraction, and the change is influenced by temperature and varies with the solvent. The decrease in radical concentration in most solvents at temperatures lower than their boiling points is attribute to coupling of free radicals dissolved from the coals, while the increase in radical concentration at high temperatures and in NMP is attributed to the cleavage of weak bonds in coals by the solvents.

The reaction of volatiles in a coal pyrolysis reactor determines the yield and quality of tar. This paper studies the yield, group composition and radical concentration of tars obtained from pyrolysis of a subbituminous coal, mainly on the effect of the tars' residence time in the pyrolysis reactor and in post-pyrolysis heating. The latter operation simulates the environment of tars, if they were in a large fast pyrolysis reactor. It is found that an increase in the volatiles' residence time in the pyrolysis reactor reduces the yield and increases the radical concentration of tars. The pitch fraction of the tars is mainly responsible for coke formation which occurs significantly at temperatures higher than 420 °C. The tars contain radicals, mainly in their coke and pitch fractions. The coke concentration in the tars increases with increasing heating time, linearly at 420 and 450 °C but in a sigmoidal pattern at higher temperatures. The coking behavior within 10 min can be expressed by the zero-order or zero-order + autocatalytic kinetics with activation energies of 128–138 kJ/mol.

An activated carbon fiber (ACF) cathode was fabricated and used to treat glyphosate containing wastewater by the Electro-Fenton (EF) process. The results showed that glyphosate was rapidly and efficiently degraded and the BOD5/COD ratio was increased to >0.3 implying the feasibility of subsequent treatment of the treated wastewater by biological methods. The results of ion chromatography and HPLC measurements indicated that glyphosate was completely decomposed. Effective OH generation and rapid recycling/recovery of the Fe2+ ions at the cathode were responsible primarily for the high performance of the ACF-EF process. Factors such as inlet oxygen gas flow rate, Fe2+ dosage, initial glyphosate concentration, applied current intensity, and solution pH that may affect the efficiency of the ACF-EF process were further studied and the optimum operation condition was established. Results of SEM/EDX, BET and XPS analysis showed the deposition of highly dispersed fine Fe2O3 particles on the ACF surface during the EF reaction. The possibility of using the Fe2O3-ACF as iron source in the EF process was assessed. Results showed that the Fe2O3-ACF electrode was effective in degrading glyphosate in the EF process. The deposition of Fe2O3 particles on the ACF electrode had no adverse effect on the reusability of the ACF cathode.

The pyrolysis of 14 coals with carbon contents (C%) of 67.5–94.9% are studied in the presence of 9,10-dihydrophenanthrene (DHP) at 440 °C. The amounts of stable radicals in the coals and that generated in the pyrolysis are quantified by electron spin resonance (ESR). The amounts of active radicals generated in the pyrolysis are quantified by the amounts of hydrogen donated by DHP. The changes in quantity of these radicals during the pyrolysis are correlated with the parameters representing the coal rank (C%, the amounts of aromatic and aliphatic carbon). It is found that the quantity of stable radicals of the coals in the pyrolysis increases with an increase in C%. The lignites and bituminous coals break up significantly in the first 2 min in the pyrolysis. All the coals contain some rigid structures that do not break at 440 °C and the structure can be categorized to fusinite. The quantities of active radicals generated in the pyrolysis are approximately 3 orders of magnitude higher than that of the stable radicals in the coals. The total amounts of cleavable bonds in the coals and the rate constants of the bond cleavage are determined by the first order kinetics.

OEGylation is an attractive approach to modifying poly(amino acid)s. OEG conjugation improves water-solubility of poly(amino acid)s, and confers possible thermal-responsive functionality for the conjugated poly(amino acid)s. Nevertheless, the impact of OEG architecture and the manner in which the OEG moiety interferes with the performances of poly(amino acid)s remain a work in progress. In this study, a series of new linear and Y-shaped OEG-substituted poly(glutamic acid)s were designed and synthesized. It is found that the thermoresponsive behavior of OEGylated poly(glutamic acid)s experiences steric repulsion effect, the strengths of which are architecture and length-dependent, and grows pronounced only when the number of the OEG units is ≥6. Notably, the Y-shaped architecture is able to stabilize the helicity of poly(glutamic acid) backbones, while maintaining higher α-helical conformation than its linear counterparts. In sum, our result indicate that Y-shaped architecture is more appropriate toward OEGylating poly(amino acid)s for biomedical applications.

Recent theoretical studies have extended the Berry phase framework to account for higher electric multipole moments, quadrupole and octupole topological phases have been proposed. Although the two-dimensional quantized quadrupole insulators have been demonstrated experimentally, octupole topological phases have not previously been observed experimentally. Here we report on the experimental realization of classical analog of octupole topological insulator in the electric circuit system. Three-dimensional topolectrical circuits for realizing such topological phases are constructed experimentally. We observe octupole topological states protected by the topology of the bulk, which are localized at the corners. Our results provide conclusive evidence of a form of robustness against disorder and deformation, which is characteristic of octupole topological insulators. Our study opens a new route toward higher-order topological phenomena in three-dimensions and paves the way for employing topolectrical circuitry to study complex topological phenomena., Comment: Physical Review B Rapid Communication

Polyaniline (PANI) nanobelts were successfully synthesized by a low temperature induced polymerization method. Morphology results confirmed that p-phenylenediamine and low temperature were vital for the formation of PANI nanobelts. Comparative study between a rotating packed bed (RPB) and a stirring tank reactor demonstrated that high mixing degree of raw materials was beneficial for the growth of uniformly shaped PANI nanobelts. Electrochemical analysis revealed that the PANI nanobelts obtained in RPB possessed a specific capacitance of 304.4F/g at 0.5 A/g and a capacitance retention of 40.65% after 1000 cycles, respectively.

Motivation The metabolites of exogenous and endogenous compounds play a pivotal role in the domain of metabolism research. However, they are still unclear for most chemicals in our environment. The in silico methods for predicting the site of metabolism (SOM) are considered to be efficient and low-cost in SOM discovery. However, many in silico methods are focused on metabolism processes catalyzed by several specified Cytochromes P450s, and only apply to substrates with special skeleton. A SOM prediction model always deserves more attention, which demands no special requirements to structures of substrates and applies to more metabolic enzymes. Results By incorporating the use of hybrid feature selection techniques (CHI, IG, GR, Relief) and multiple classification procedures (KStar, BN, IBK, J48, RF, SVM, AdaBoostM1, Bagging), SOM prediction models for six oxidation reactions mediated by oxidoreductases were established by the integration of enzyme data and chemical bond information. The advantage of the method is the introduction of unlabeled SOM. We defined the SOM which not reported in the literature as unlabeled SOM, where negative SOM was filtered. Consequently, for each type of reaction, a series of SOM prediction models were built based on information about metabolism of 1237 heterogeneous chemicals. Then optimal models were attained through comparisons among these models. Finally, independent test set was used to validate optimal models. It demonstrated that all models gave accuracies above 0.90. For receiver operating characteristic analysis, the area under curve values of all these models over 0.906. The results suggested that these models showed good predicting power. Availability and implementation All the models will be available when contact with wangyun@bucm.edu.cn Supplementary information Supplementary data are available at Bioinformatics online.

Fast and slow pyrolysis are good means of biomass transformation. Studying the formation of bio-char is not only helpful to intensify the transformation of biomass, but also to improve its performance. However, little work has been reported on the similarities and differences of bio-chars in fast and slow pyrolysis. We investigated the fast and slow pyrolysis of walnut shell at 400–800 °C to find the evolvement law of bio-char. It was found that the formation mechanism of bio-char in fast pyrolysis is almost the same as that in slow pyrolysis. There are two stages in the formation of bio-char: the generation of free radicals caused by the covalent bond breaking at temperature less than 600 °C; the reduce of free radicals through the condensation reactions from 600 to 800 °C. The contents of various oxygen-containing functional groups presented regularity with the increase of pyrolysis temperature, in which the quinone group increases with the pyrolysis temperature increasing, which phenomenon could be used as a signal to exhibit the stabilization of oxygen in bio-char. The bio-char yields, free radicals and quinone contents are slightly higher in slow pyrolysis. The graphite crystals in bio-char have the tendency of microcrystallization with the increase of temperature, in which progress the fast pyrolysis has superiority at the low temperature.

Hyperspectral LiDAR (HSL) possesses the advantages of the LiDAR and the hyperspectral detection, and detects ranging and spectrum information synchronously, by one HSL system. The data fusion is also avoided. At present, the spectrum range of reported HSLs usually covers only 500 nm-1000 nm (from visual (VIS) to near infrared (NIR) band). However, there is requirement to extend the spectrum range to short wave infrared (SWIR) band, which often contains more useful spectral information. In this paper, a HSL covering the spectrum from VIS to SWIR is reported. In the HSL, the echoes are divided into two sections and are detected by the different optoelectronic devices, of which the spectral response ranges are respectively compatible to the corresponding echoes. The HSL detection experiment in the laboratory was carried out. The waveforms of the echoes were analyzed, and the spectra of different targets were measured by the HSL. The experiment results demonstrate the capability of the prototyped HSL that obtaining the ranging information and the spectrum information of the targets in VIS-SWIR bands synchronously.

Hyperspectral Light Detection And Ranging (Hyperspectral LiDAR), a recently developed technique, combines the advantages of the LiDAR and hyperspectral imaging and has been attractive for many applications. Supercontinuum laser (SC laser), a rapidly developing technique offers hyperspectral LiDAR a suitable broadband laser source and makes hyperspectral Lidar become an installation from a theory. In this paper, the recent research and progressing of the hyperspectral LiDAR are reviewed. The hyperspectral LiDAR has been researched in theory, prototype system, instrument, and application experiment. However, the pulse energy of the SC laser is low so that the range of the hyperspectral LiDAR is limited. Moreover, considering the characteristics of sensors and A/D converter, in order to obtain the full waveform of the echo, the repetition rate and the pulse width of the SC laser needs to be limited. Recently, improving the detection ability of hyperspectral LiDAR, especially improving the detection range, is a main research area. A higher energy pulse SC laser, a more sensitive sensor, or some algorithms are applied in hyperspectral LiDAR to improve the detection distance from 12 m to 1.5 km. At present, a lot of research has been focused on this novel technology which would be applied in more applications.