Material decomposition of spectral CT images via attention-based global convolutional generative adversarial network

Spectral computed tomography(CT)based on photon counting detectors can resolve the energy of every single photon interacting with the sensor layer and be used to analyze material attenuation information under different energy ranges,which can be helpful for material decomposition studies.However,there is a considerable amount of inherent quantum noise in narrow energy bins,resulting in a low signal-to-noise ratio,which can consequently affect the material decomposition performance in the image domain.Deep learning technology is currently widely used in medical image segmentation,denoising,and recognition.In order to improve the results of material decomposition,we propose an attention-based global convolutional generative adversarial network(AGC-GAN)to decompose different materials for spectral CT.Specifically,our network is a global convolutional neural network based on an attention mechanism that is combined with a generative adversarial network.The global convolutional network based on the attention mechanism is used as the generator,and a patchGAN discriminant network is used as the discriminator.Meanwhile,a clinical spectral CT image dataset is used to verify the feasibility of our proposed approach.Extensive experimental results demonstrate that AGC-GAN achieves a better material decomposition performance than vanilla U-Net,fully convolutional network,and fully convolutional denseNet.Remarkably,the mean intersection over union,structural similarity,mean precision,PAcc,and mean F1-score of our method reach up to 87.31%,94.83%,93.22%,97.39%,and 93.05%,respectively.

Photon-counting computed tomography thermometry via material decomposition and machine learning

Thermal ablation procedures,such as high intensity focused ultrasound and radiofrequency ablation,are often used to eliminate tumors by minimally invasively heating a focal region.For this task,real-time 3D temperature visualization is key to target the diseased tissues while minimizing damage to the surroundings.Current computed tomography(CT)thermometry is based on energy-integrated CT,tissue-specific experimental data,and linear relationships between attenuation and temperature.In this paper,we develop a novel approach using photon-counting CT for material decomposition and a neural network to predict temperature based on thermal characteristics of base materials and spectral tomographic measurements of a volume of interest.In our feasibility study,distilled water,50 mmol/L CaCl2,and 600 mmol/L CaCl2 are chosen as the base materials.Their attenuations are measured in four discrete energy bins at various temperatures.The neural network trained on the experimental data achieves a mean absolute error of 3.97°C and 1.80°C on 300 mmol/L CaCl2 and a milk-based protein shake respectively.These experimental results indicate that our approach is promising for handling non-linear thermal properties for materials that are similar or dis-similar to our base materials.

Decomposition of Different Organic Materials and Variation of Active Organic Carbon and Nitrogen Contents in Tobacco-planted Soil

The oilseed cake, vetch, rapeseed straw, wheat straw and corn straw were buried in tobacco-planted soil. The decomposition rates, the variation of active organic C and N contents in the residues and the relationship between active organic C and N contents and decomposition rate were investigated. The results showed the decomposition rates of different organic materials were all high in the early period and then low in the late period. Among the organic materials, the decomposition rates ranked as oilseed cake 〉 vetch 〉 wheat straw and rapeseed straw 〉 corn straw. The decomposition rate was positively related to total N content （P〈0.01）, but was negatively related to the active organic C/N ratio （P〈0.01）. However, there was no significant relationship between decomposition ratio and active organic C content. With the proceeding of decomposition, the active organic C content and the total N content in rapeseed straw, vetch, wheat straw and corn straw all trended to increase, but the active organic C/N ratio trended to decrease. However, the variation of active organic C content, total N content and active organic C/N ratio in oilseed cake was on the contrary.

Progress in the research on organic piezoelectric catalysts for dye decomposition

Organic contaminants have posed a direct and substantial risk to human wellness and the environment.In recent years,piezo-electric catalysis has evolved as a novel and effective method for decomposing these contaminants.Although piezoelectric materials offer a wide range of options,most related studies thus far have focused on inorganic materials and have paid little attention to organic materi-als.Organic materials have advantages,such as being lightweight,inexpensive,and easy to process,over inorganic materials.Therefore,this paper provides a comprehensive review of the progress made in the research on piezoelectric catalysis using organic materials,high-lighting their catalytic efficiency in addressing various pollutants.In addition,the applications of organic materials in piezoelectric cata-lysis for water decomposition to produce hydrogen,disinfect bacteria,treat tumors,and reduce carbon dioxide are presented.Finally,fu-ture developmental trends regarding the piezoelectric catalytic potential of organic materials are explored.

Progress on the application of graphene-based composites toward energetic materials:A review

Carbon material is an important additive in energetic materials.Graphene is a monolayer carbon material in which carbon atoms are arranged in two-dimensional honeycomb structure,who has special optical,electrical,and mechanical properties.Recently,the application of graphene-based composites in energetic materials has received extensive attention.This review mainly summarizes the applications of graphene and graphene-based nanomaterials in energetic materials.The effects of these materials on the thermal stability,sensitivity,mechanical property,ignition and combustion of energetic materials were discussed.Furthermore,the progress of functionalized modification of graphene has been summarized,including covalent bonding modification and doping modification.These studies show that graphenebased materials exhibit excellent performances and might emerge as promising candidate for energetic materials.

Facile preparation of Fe/N-based biomass porous carbon composite towards enhancing the thermal decomposition of DAP-4

Fe/N-based biomass porous carbon composite(Fe/N-p Carbon) was prepared by a facile high-temperature carbonization method from biomass,and the effect of Fe/N-p Carbon on the thermal decomposition of energetic molecular perovskite-based material DAP-4 was studied.Biomass porous carbonaceous materials was considered as the micro/nano support layers for in situ deposition of Fe/N precursors.Fe/Np Carbon was prepared simply by the high-temperature carbonization method.It was found that it showed the inherent catalysis properties for thermal decomposition of DAP-4.The heat release of DAP-4/Fe/N-p Carbon by DSC curves tested had increased slightly,compared from DAP-4/Fe/N-p Carbon-0.The decomposition temperature peak of DAP-4 at the presence of Fe/N-p Carbon had reduced by 79°C from384.4°C(pure DAP-4) to 305.4°C(DAP-4/Fe/N-p Carbon-3).The apparent activation energy of DAP-4thermal decomposition also had decreased by 29.1 J/mol.The possible catalytic decomposition mechanism of DAP-4 with Fe/N-p Carbon was proposed.

Price prediction of power transformer materials based on CEEMD and GRU

The rapid growth of the Chinese economy has fueled the expansion of power grids.Power transformers are key equipment in power grid projects,and their price changes have a significant impact on cost control.However,the prices of power transformer materials manifest as nonsmooth and nonlinear sequences.Hence,estimating the acquisition costs of power grid projects is difficult,hindering the normal operation of power engineering construction.To more accurately predict the price of power transformer materials,this study proposes a method based on complementary ensemble empirical mode decomposition(CEEMD)and gated recurrent unit(GRU)network.First,the CEEMD decomposed the price series into multiple intrinsic mode functions(IMFs).Multiple IMFs were clustered to obtain several aggregated sequences based on the sample entropy of each IMF.Then,an empirical wavelet transform(EWT)was applied to the aggregation sequence with a large sample entropy,and the multiple subsequences obtained from the decomposition were predicted by the GRU model.The GRU model was used to directly predict the aggregation sequences with a small sample entropy.In this study,we used authentic historical pricing data for power transformer materials to validate the proposed approach.The empirical findings demonstrated the efficacy of our method across both datasets,with mean absolute percentage errors(MAPEs)of less than 1%and 3%.This approach holds a significant reference value for future research in the field of power transformer material price prediction.

Decomposition characteristics of organic materials and their effects on labile and recalcitrant organic carbon fractions in a semi-arid soil under plastic mulch and drip irrigation

Labile organic carbon （LC） and recalcitrant organic carbon （RC） are two major fractions of soil organic carbon （SOC） and play a critical role in organic carbon turnover and sequestration. The aims of this study were to evaluate the variations of LC and RC in a semi-arid soil （Inner Mongolia, China） under plastic mulch and drip irrigation after the application of organic materials （OMs）, and to explore the effects of OMs from various sources on LC and RC by probing the decomposition characteristics of OMs using in-situ nylon mesh bags burying method. The field experiment included seven treatments, i.e., chicken manure （CM）, sheep manure （SM）, mushroom residue （MR）, maize straw （MS）, fodder grass （FG）, tree leaves （TL） and no OMs as a control （CK）. Soil LC and RC were separated by Huygens D＇s method （particle size-density）, and the average soil mass recovery rate and carbon recovery rate were above 95%, which indicated this method was suitable for carbon pools size analysis. The LC and RC contents significantly （P〈0.01） increased after the application of OMs. Moreover, LC and RC contents were 3.2%-8.6% and 5.0%-9.4% higher in 2016 than in 2015. The applications of CM and SM significantly increased （P〈0,01） LC content and LC/SOC ratio, whereas they were the lowest after the application of TL. However, SOC and RC contents were significantly higher （P〈0.01） after the applications of TL and MS. The correlation analysis indicated the decomposition rate of OMs was positively related with LC content and LC/SOC ratio. In addition, lignin, polyphenol, WOM （total water-soluble organic matter）, WHA （water-soluble humic acid）, HSL （humicdike substance） and HAL （humic acid-like） contents in initial OMs played important roles in SOC and RC. In-situ nylon mesh bags burying experiment indicated the decomposition rates of CM, SM and MS were significantly higher than those of MR, FG, and TL. Furthermore, MS could result in more lignin derivatives, WHA, and HAL polymers in shorter time during the decomposition process. In conclusion, the application of MS in the semi-arid soil under a long-term plastic mulch and drip irrigation condition could not only improve soil fertility, but also enhance soil carbon sequestration.

Decomposition Analysis on Direct Material Input and Dematerialization of Mining Cities in Northeast China

Material dematerialization is a basic approach to reduce the pressure on the resources and environment and to realize the sustainable development. The material flow analysis and decomposition method are used to calculate the direct material input (DMI) of 14 typical mining cities in Northeast China in 1995–2004 and to analyze the demateri- alization and its driving factors in the different types of mining cities oriented by coal, petroleum, metallurgy and multi-resources. The results are as follows: 1) from 1995 to 2006, the increase rates of the DMI and the material input intensity of mining cities declined following the order of multi-resources, metallurgy, coal, and petroleum cities, and the material utilizing efficiency did following the order of petroleum, coal, metallurgy, and multi-resources cities; 2) during the research period, all the kinds of mining cities were in the situation of weak sustainable development in most years; 3) the pressure on resources and environment in the multi-resources cities was the most serious; 4) the petro- leum cities showed the strong trend of sustainable development; and 5) in recent years, the driving function of eco- nomic development for material consuming has continuously strengthened and the controlling function of material utilizing efficiency for it has weakened. The key approaches to promote the development of circular economy of min- ing cities in Northeast China are put forward in the following aspects: 1) to strengthen the research and development of the technique of resources’ cycling utilization, 2) to improve the utilizing efficiency of resources, and 3) to carry out the auditing system of resources utilization.

Effects of phase change material(PCM)-based nanocomposite additives on thermal decomposition and burning characteristic of high energy propellants containing RDX

A kind of phase change material(PCM)-based nanocomposite was prepared and added into high energy propellants containing RDX as additives to investigate its effect on thermal decomposition and burning characteristic of high energy propellants.The effect of PCM-based nanocomposites on thermal decomposition of high energy propellants is investigated by TG/DSC-FTIR-MS technology.Due to the delayed protection effect(PCM-based nanocomposites can absorb lots of heat at the range of certain temperature when it undergoes structure change or phase transitions)of PCM-based nanocomposites under the thermal decomposition condition,the thermal stability of high energy propellants modified with PCMbased nanocomposites is improved.At the same time,the concentration of N2,NO2,H2O and CO_(2)is increased during thermal decomposition of high energy propellants whereas NO and CO is decreased.The burning gaseous products and burning characteristic of high energy propellants are studied by the combination of closed bomb test and Fourier transform infrared spectrum.The main burning gaseous products are N2,CO_(2),CO,H2O,CH4,etc.After the high energy propellant modified with PCM-based nanocomposites,the concentration of CH4is increased while CO,CO_(2) and H2O is decreased under the high-pressure burning condition.The progressivity factor of high energy propellants is increased by22.2%compared with the control sample while the maximum pressure is merely decreased 1.25%after the addition of the PCM-based nanocomposite,thus PCM-based nanocomposites can be used to adjust the burning process and improve the burning progressivity of high energy propellants.This study is expected to boost the practical application of PCM-based nanocomposite to the propellant formulation and effectively control the burning characteristic of high energy propellants.

Advances in Microbial Strains and Bedding Materials in a Deep-Litter System for Pig Breeding

The selection and compatibility of the microbial strains and bedding materials in a deep-litter system is the primary issues for this ecological breeding technology. In this paper, we analyzed and summarized the categories of microbial strains and bedding materials suitable for a deep-litter system, the fermentation properties of different microbes, the parameter requirements of bedding materials, and the fermentation process led by functional microbial flora in a deep-litter system, with the objective to provide theoretical bases and practical guidance for the promotion of deep-litter breeding method nationwide.

Characterization and technology of fast reducing roasting for fine iron materials

The features of the techniques of fast reducing roasting （FRR） and conventional magnetic roasting, as well as tremendous demands of iron ores in iron and steel industry of China, were briefly described. The test equipment suitable for FRR of fine-grained materials was introduced. Weakly magnetic materials with grain size of 〈0.30 mm were converted into strongly magnetic materials by FRR for several to dozens of seconds. In a weakly reducing atmosphere and at 740-800 ~C, refractory powder iron material （〈0.30 mm） which is rich in specularite, limonite and Mg-Mn siderite was subjected to FRR for a few seconds to 60 s. Concentrate with iron grade of 55.67%-55.21%, high contents of Mg and Mn in the ore is obtained and the yield of magnetic separation reaches 81.66%-86.57%. The results of X-ray diffraction （XRD） analysis and magnetism detection of the material before and after FRR indicate that weakly magnetic material is mainly converted into strongly magnetic material Fe304 with specific saturation magnetic moment. The efficiency of FRR is consistent with TFe recovery of magnetic separation; meantime, the specific sa^u＇ation magnetic moment increases from 33 to 42 times after FRR. Calculations show that speeds of flash magnetic roasting are obtained from several dozen to two or three hundred times, compared with rotary kiln or shaft furnace. This indicates that it is practicable to use the fast reducing roasting technique to improve the comprehensive utilization of iron ore resources.

Catalysis of Nanometer α-Fe_2O_3 on the Thermal Decomposition of AP

Nanometer α-Fe2O3 catalysts were prepared by hydrolyzation in high temperature. Three kinds of precipitators, NaOH, （NH4）2CO3 and urea were used to compare the effect in the process of hydrolyzation. Nanometer sizer, transmission electron microscopy （TEM） and X-ray diffraction （XRD） were employed to test the profiles and diameters of the product particles. The test results indicate that the production is nanometer α-Fe2O3 with narrow particle size distribution （PSD） and good dispersibility. The catalysts are mixed with ammonia perchlorate （AP） in 1.0 wt.%. And the composite particles of catalysts with AP are prepared using a new solvent-nonsolvent method. Differential thermal analyzer （DTA） is employed to analysis the thermal decomposition of the composite particles and pure AP sample. The results imply that the thermal decomposition curve peaks of the samples in which nanometer α-Fe2O3 catalysts are added appear comparatively more ahead than that of pure AP sample. Among these mixtures added nanometer material, the smaller the particle diameter of catalyst is, the more ahead the thermal decomposition curve peaks of AP appear. The high and low temperature thermal decomposition curve peaks of AP mixed with the catalyst deposed by urea are more ahead of 77.8?℃ and 9.7?℃ than that of pure AP, respectively. The mechanism of the catalyst deposed by urea with smaller diameter and the distinct catalysis of the particles on the thermal decomposition of AP are discussed.

Enhanced CO2 decomposition via metallic foamed electrode packed in self-cooling DBD plasma device

A self-cooling dielectric barrier discharge reactor, packed with foamed Cu and Ni mesh and operated at ambient conditions, was used for the composition of CO2 into CO and O2.The influences of power, frequency, and other discharge characteristics were investigated in order to have a better understanding of the effect of the packing materials on CO2 decomposition.It is found that porous foamed Cu and Ni not only played a role as the carrier of energy transformation and electrode distributed in discharge gaps but also promoted the equilibrium shifting toward the product side to yield more CO by consuming some part of O2 and O radicals generated from the decomposition of CO2.The maximum CO2 decomposition rates of 48.6%and 49.2% and the maximum energy efficiency of 9.71% and 10.18% were obtained in the foamed Ni and Cu mesh, respectively.

Kinetic Laws of Heating Initiated Reactions for Materials in Aerospace Applications

Cure and decomposition reaction kinetics of typical organic materials in aerospace applications are introduced.From the data of dynamic differential scanning calorimetry(DSC)experiments,and based on changes of the peak temperatures(T_(p))with different heating rates(β),a linear equation,T_(p)=T_(1)+△Tlnβ,has been obtained more reasonably.The above equation can be used to explain some laws of higher or lower of apparent activation energies(E_(a)),by which the apparent activation energy(E_(a))is nearly equal to RT^(2)_(1)/△T.A number of kinetic investigations of typical thermosetting resins and energetic materials in aerospace applications were chosen to validate the above equations.

Experimental Research on Toluene Degradation in Plasma as the Driving Force of Nanomaterials

Plasma technology has some shortcomings, such as higher energy consumption and byproducts produced in the reaction process. However non-thermal plasma associated with catalyst can resolve these problems. So this kind of technology was paid more and more attention to treat waste gas. In this paper, we make use of this technology to decompose toluene under different electric field and packed materials. At the same time, the mechanism of toluene decomposition using plasma and catalyst is discussed. The experimental results show toluene decomposition increases with electric field strength increasing and flow velocity and initial concentration decreasing. There are four conditions in plasma: without packed materials (1);with packed materials (2);with BaTiO3 in the surfaces of packed materials (3);and with nanometer Ba0.8Sr0.2Zr0.1Ti0.9O3 (4). Toluene decomposition represents a obvious trend, that is, η(4) > η(3) > η(2) > η(1). The best decomposition efficiency of toluene arrives at 95%.

Spherical and Radiate Ni Particles Prepared by the Tartrate Precipitation and Thermal Decomposition Method

Nickel tartrate precursor particles were synthesized by the liquid phase precipitation method in an ethanol-water-ammonia mixed solution, with tartaric acid and using nickel chlorate as raw materials, with the pH value controlled at 4.0, and the temperature controlled at 50 ℃. Nickel particles with complicated morphology were prepared by the decomposition of nickel taratrate precursor particles at temperatures of 360, 380 and 400 ℃, respectively. The study of infrared spectroscopy （IR） indicated that the product was pure nickel tartrate. The studies of the atomic absorption spectrometry （AAS） and organic elemental analysis （OEA） indicated that the molar ratio of Ni2＋ to （C4H4O6）2- is close to 1：1. The studies of the differential scanning calorimeter and thermo-gravimetric analysis （DSC-TG） indicated that the chemical formula Niz（C4H4O6） 2.5H2O was confirmed. The studies of X-ray diffractions （XRD） indicated that the silvery white metal powders were pure Ni, with a face-centered cubic crystal structure. The images of scanning electron microscopy （SEM） showed that the morphology of metal Ni particles was obvious spherical and radiate. The diameter of nickel tartrate particles was about 60 μm, which consisted of many nanolathes; and the diameter of metal Ni particles was about 30 μm, which consisted of many lathes about 0.5 μm in thickness.

Precipitation of flaky moolooite and its thermal decomposition

Moolooite particles with flaky morphology were synthesized by mixing dilute solutions of copper nitrate and sodium oxalate in the presence of citric acid. Solution p H value, citric acid concentration, and stirring were found to have large effect on the shape of the precipitated particles. Under the stirring, the radial area of flaky moolooite particles was enlarged and extended to become a thinner and larger flake. This is ascribed to growth promotion caused by the selective absorption of citric ligands onto a particular crystalline surface of the moolooite particles. Flaky shape of the moolooite particles tended to become spherical and disappeared completely when decomposed under an Ar atmosphere, leading to the formation of large porous aggregated particles composed of many tiny nanosized copper crystals.

Highly efficient and stable electrooxidation of methanol and ethanol on 3D Pt catalyst by thermal decomposition of In2O3 nanoshells

In this paper In2O3nanoshells have been synthesized via a facile hydrothermal approach. The nanoshells can be completely cracked into pony-size nanocubes by annealing, which are then used as a support of Pt catalyst for methanol and ethanol electrocatalytic oxidation. The prepared In2O3and supported Pt catalysts (Pt/In2O3) were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), field effect scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry and electrochemical impedance spectroscopy (EIS) were carried out, indicating the excellent catalytic performance for alcohol electrooxidation can be achieved on Pt/In2O3nanocatalysts due to the multiple active sites, high conductivity and a mass of microchannels and micropores for reactant diffusions arising from 3D frame structures compared with that on the Pt/C catalysts. © 2016 Science Press

电力嗅觉传感原理与关键技术研究综述

仿生感知技术在电力设备状态监测与故障诊断领域已被广泛应用。结合微型气体传感器与智能算法的电力嗅觉技术,通过检测绝缘介质的特征分解气体,可以有效评估电力设备的故障类型和严重程度。因其成本低、体积小和集成度高的优势,电力嗅觉技术受到越来越多关注。因此,该文针对SF6气体绝缘设备、空气绝缘设备、变压器、电力电缆和储能电池的应用背景,梳理了当前电力嗅觉传感技术的研究现状。首先,总结了不同电力设备状态劣化的产气特性及内在机理,分析了特征分解气体的异同;之后,针对不同特征分解气体,总结了电力嗅觉敏感材料的研究进展与改进方向;然后,对比了陶瓷基底、柔性基底和硅基底的封装差异性,提出了电力嗅觉传感器件的芯片化、集成化发展方向;最后,讨论了基于特征工程和数据驱动的传感器信号处理算法,点明了边缘计算技术在电力嗅觉智能算法方面的应用潜力。该文对电力嗅觉传感原理与关键技术进行了详细归纳,强调了在气体分析方法、气敏材料开发、传感器制备技术和智能算法应用等方面的技术创新潜力,为电力设备的智能化发展提供了指导方向。