Upper Andean tropical forests are renowned for their extraordinary biodiversity and heterogeneous environmental conditions.Despite the critical role of litter decomposition in carbon and nutrient cycles,its dynamics i...Upper Andean tropical forests are renowned for their extraordinary biodiversity and heterogeneous environmental conditions.Despite the critical role of litter decomposition in carbon and nutrient cycles,its dynamics in this region remains unexplored at finer scales.This study investigates how micro site conditions influence litter decomposition of 15 upper Andean species over time.A reciprocal translocation field experiment was conducted over 18 months in 14 permanent plots within four sites in Colombian Andean mountain forests.Each plot contained three litterbeds(microsites),each with the 15 species,harvested at 3,6,12 and 18 months,totaling 2520 litterbags.Different forest variables,including canopy openness,leaf area index,slope and depth of litter,were measured in each litterbed.ANOVAs and linear mixed models were used to assess variation between sites and plots respectively,while multiple linear regression analyses evaluated the effects of forest variables on decay rates over time at the micro site scale.Results showed differences in absolute decay rates between sites but consistent relative decay rates,indicating varying magnitudes of decomposition,yet maintaining the same order based on their litter quality.Decay rates varied between species,with more variation in labile species compared to recalcitrant ones.Despite substantial variation in forest characteristics within sites,their influence on litter decomposition was minimal and declined over time.This suggests that,at finer spatial scales,the forest microenvironment plays a lesser role in litter decomposition,with litter quality emerging as the primary driver.This study is a step towards understanding the fine-scale dynamics of litter decomposition in upper Andean tropical forests,highlighting the intricate interplay between microenvironmental factors and decomposition processes.展开更多
Underwater imaging posts a challenge due to the degradation by the absorption and scattering occurred during light propagation as well as poor lighting conditions in water medium Although image filtering techniques ar...Underwater imaging posts a challenge due to the degradation by the absorption and scattering occurred during light propagation as well as poor lighting conditions in water medium Although image filtering techniques are utilized to improve image quality effectively, problems of the distortion of image details and the bias of color correction still exist in output images due to the complexity of image texture distribution. This paper proposes a new underwater image enhancement method based on image struc- tural decomposition. By introducing a curvature factor into the Mumford_Shah_G decomposition algorithm, image details and struc- ture components are better preserved without the gradient effect. Thus, histogram equalization and Retinex algorithms are applied in the decomposed structure component for global image enhancement and non-uniform brightness correction for gray level and the color images, then the optical absorption spectrum in water medium is incorporate to improve the color correction. Finally, the en- hauced structure and preserved detail component are re.composed to generate the output. Experiments with real underwater images verify the image improvement by the proposed method in image contrast, brightness and color fidelity.展开更多
The structural damage identification through modal data often leads to solving a set of linear equations. Special numerical treatment is sometimes required for an accurate and stable solution owing to the ill conditio...The structural damage identification through modal data often leads to solving a set of linear equations. Special numerical treatment is sometimes required for an accurate and stable solution owing to the ill conditioning of the equations. Based on the singular value decomposition (SVD) of the coefficient matrix, an error based truncation algorithm is proposed in this paper. By rejection of selected small singular values, the influence of noise can be reduced. A simply-supported beam is used as a simulation example to compare the results to other methods. Illustrative numerical examples demonstrate the good efficiency and stability of the algorithm in the nondestructive identification of structural damage through modal data.展开更多
A hierarchical structural decomposition analysis(SDA) model has been developed based on process-level input-output(I-O) tables to analyze the drivers of energy consumption changes in an integrated steel plant during 2...A hierarchical structural decomposition analysis(SDA) model has been developed based on process-level input-output(I-O) tables to analyze the drivers of energy consumption changes in an integrated steel plant during 2011-2013. By combining the principle of hierarchical decomposition into D&L method, a hierarchical decomposition model for multilevel SDA is obtained. The developed hierarchical IO-SDA model would provide consistent results and need less computation effort compared with the traditional SDA model. The decomposition results of the steel plant suggest that the technology improvement and reduced steel final demand are two major reasons for declined total energy consumption. The technical improvements of blast furnaces, basic oxygen furnaces, the power plant and the by-products utilization level have contributed mostly in reducing energy consumption. A major retrofit of ancillary process units and solving fuel substitution problem in the sinter plant and blast furnace are important for further energy saving. Besides the empirical results, this work also discussed that why and how hierarchical SDA can be applied in a process-level decomposition analysis of aggregated indicators.展开更多
As China's energy intensity fluctuated in recent years, it is necessary to examine whether this fluctuation happened at a regional level. This paper establishes a decomposition model by using the structural decomp...As China's energy intensity fluctuated in recent years, it is necessary to examine whether this fluctuation happened at a regional level. This paper establishes a decomposition model by using the structural decomposition analysis (SDA) method at a regional level. Then this model is employed to empirically analyze the changes of Beijing's energy intensity. The conclusions are as follows: during 2002-2010, except petroleum, the energy intensity decreased and the changes were mostly attributed to the technology changes, while the final use variation actually increased the energy intensity; comparing different periods of 2002-2010, the decline rates of energy intensity for coal and hydropower were decreasing, resulting from the production technology being more energy-intensive than before; the energy intensity changes of petroleum firstly increased substantially and then decreased moderately.展开更多
Analysis of carbon emission mechanism based on regional perspectives is an im- portant research method capable of achieving energy savings and emission reductions. Xin- jiang, an important Chinese energy production ba...Analysis of carbon emission mechanism based on regional perspectives is an im- portant research method capable of achieving energy savings and emission reductions. Xin- jiang, an important Chinese energy production base, is currently going through a period of strategic opportunities for rapid development. Ensuring stable socio-economic development while achieving energy savings and meeting emission reductions targets, is the key issue currently facing the region. This paper is based on the input-output theory, and conducts a structural decomposition analysis on the factors affecting energy-related carbon emissions in Xinjiang from 1997 to 2007; this analysis employs a hybrid input-output analysis framework of ＂energy - economy - carbon emissions＂. （1） Xinjiang＇s carbon emissions from energy con- sumption increased from 20.70 million tons in 1997 to 40.34 million tons in 2007; carbon emissions growth was mainly concentrated in the production and processing of energy re- sources, the mining of mineral resources, and the processing industry. （2） The analysis of the direct effects of the influencing factors on carbon emissions showed that the change in per capita GDP, the final demand structure, the population scale, and the production structure were the important factors causing an increase in carbon emissions, while the decrease in carbon emission intensity during this period was the important influencing factor in stopping the growth of carbon emissions. This showed that while the sizes of Xinjiang＇s economy and population were growing, the economic structure had not been effectively optimized and the production technology had not been efficiently improved, resulting in a rapid growth of carbon emissions from energy consumption. （3） The analysis of the indirect effects of the influencing factors of carbon emission showed that the inter-provincial export, fixed capital formation, and the consumption by urban residents had significant influence on the changes in carbon emissions from energy consumption in Xinjiang. （4） The growth of investments in fixed assets of carbon intensive industry sectors, in addition to the growth of inter-provincial exports ofenergy resource products, makes the transfer effect of inter-provincial ＂embodied carbon＂ very significant.展开更多
Eleven rare earth salts of 3-nitro-1, 2 , 4-triazol-5-one (NTO) was prepared by using aqueous solutions of lithium salt of NTO and corresponding rare earth nitrates. The formulae of these salts are determined as RE(NT...Eleven rare earth salts of 3-nitro-1, 2 , 4-triazol-5-one (NTO) was prepared by using aqueous solutions of lithium salt of NTO and corresponding rare earth nitrates. The formulae of these salts are determined as RE(NTO)3. nH2O, where RE is Y, La, Ce, Pr, Nd, Sm, Eu, Gd,Tb, Dy or Yb, and n is 6, 7, 7, 7, 8, 7, 7, 7, 5, 5 and 6 correspondingly. Their thermal decomposition mechanism was studied by using DSC, TG-DTG and FT-IR techniques under linearly increasing temperature.展开更多
This paper presents a brief description of the software toolbox, linear systems toolkit, developed in Matlab environment. The toolkit contains 66 m-functious, including structural decompositions of linear autonomous s...This paper presents a brief description of the software toolbox, linear systems toolkit, developed in Matlab environment. The toolkit contains 66 m-functious, including structural decompositions of linear autonomous systems, unforced/uuseused systems, proper systems, and singular systems, along with their applications to system factorizations, sensor/actuator selection, H-two and H-infinity control, and disturbance decoupling problems.展开更多
Alkyl dinitrites have at-tracted attention as an im-portant type of nitrosating agent and a pollution source in atmosphere.The reac-tivity and chemistry of alkyl dinitrites induced by the two ONO functional groups are...Alkyl dinitrites have at-tracted attention as an im-portant type of nitrosating agent and a pollution source in atmosphere.The reac-tivity and chemistry of alkyl dinitrites induced by the two ONO functional groups are relatively unknown.In this work,decompositions of 1,3-cyclohexane dinitrite and 1,4-cyclohexane dinitrite are studied by electron impact ionization mass spectroscopy(EI-MS).Apart from NO^(+)(m=z=30),fragment ions m=z=43 and 71 are the most abundant for the 1,3-isomer.On the other hand,fragments m=z=29,57,85,and 97 stand out in the EI-MS spectrum of 1,4-isomer.Possible dissociation mechanisms of the two dinitrites are proposed by theoretical calculations.The results reveal that the ring-opening of 1,3-cyclohexane dinitrite mainly starts from the intermediate ion(M-NO)^(+)by cleavage of twoαC-βC bonds.For 1,4-cyclohexane dinitrite,in addition to the decomposition via intermediate(M-NO)^(+),cleavage ofβC-βC bonds can occur directly from the parent cation(M)^(+).The results will help to understand the structural related chemistry of alkyl dinitrites in atmosphere and in NO transfer process.展开更多
In order to find the dominant factor of energy efficiency change, this paper uses the modified structural model to analyze energy efficiency change from 1990 to 2012 in Xinjiang. The result shows that the energy effic...In order to find the dominant factor of energy efficiency change, this paper uses the modified structural model to analyze energy efficiency change from 1990 to 2012 in Xinjiang. The result shows that the energy efficiency increase is largely due to energy technological innovation especially by the industrial sector, and the contribution from structural shift is limited. Therefore, we should vigorously support energy-saving technological progress in the industrial sector and develop the modern service industries with lower energy consumption, in order to realize the goal of improving energy efficiency.展开更多
Three complexes, [Pr（NO3）3（HL）2] （1）, [Nd（NO3）3（HL）2] （2） and [Er（NO3）3（HL）2] ·0.5H2O （3）, were synthesized from the reaction of a Schiff base ligand 2-[ （4-methylphenylimino）methyl ]-6-methox...Three complexes, [Pr（NO3）3（HL）2] （1）, [Nd（NO3）3（HL）2] （2） and [Er（NO3）3（HL）2] ·0.5H2O （3）, were synthesized from the reaction of a Schiff base ligand 2-[ （4-methylphenylimino）methyl ]-6-methoxyphenol （C15 H15 NO2, HL） with Ln（NO3）3·6H2O （Ln = Pr, Nd, Er）. Characterization by single-crystal X-ray diffraction technique, elemental analysis, molar conductance, FT-IR, UV-Vis, ^1H NMR and thermal analysis shows the title complexes are neutral molecules where the central Ln（ Ⅲ） ion is ten-coordinated in biapical anti-hexahedron prism geometry, with four oxygen atoms of the phenolic hydroxy and methoxy groups in the two bidentate Schiff base ligands and six oxygen atoms provided by the three bidentate NO3 - anions. Additionally, the kinetic mechanism of thermal decomposition of complex 3 was determined with a TG-DTG curves by both integral and differential methods. The functions of thermal decomposition reaction mechanism and the equation of kinetic compensation effect were obtained.展开更多
A new energetic organic potassium salt bis（dinitromethyl）difurazanyl ether potas- sium salt [K2（BDFE）] was synthesized, and structurally characterized by elemental analysis, IR spectra, t3C NMR and single-crystal ...A new energetic organic potassium salt bis（dinitromethyl）difurazanyl ether potas- sium salt [K2（BDFE）] was synthesized, and structurally characterized by elemental analysis, IR spectra, t3C NMR and single-crystal X-ray diffraction. K2（BDFE） crystallizes in monoclinic system, space group C2/c with a = 17.342（3）, b = 12.6943（17）, c = 8.0972（11） A, β = 110.630（2）°, V = 1668.3（4） A3, Z = 4, Dc = 2.000 g/cm3, F（000） = 1000,μ= 0.675 mm-1, S = 1.058, the final R = 0.0499 and wR = 0.1452. The K ion is eight-coordinated with eight O atoms from one water molecule and four bis（dinitromethyl）difurazanyl ethers （BDFE）, forming a distorted dodecahedral structure. Thermal decomposition of the title complex was studied by using DSC and TG-DTG. There are primarily two exothermic decomposition processes between 200 and 370 ℃.展开更多
Cold-drawn pearlitic steel wire is irreplaceably used in industry owing to its outstanding mechanical property which is dominated by the cementite/ferrite(Fe_(3)C/Fe) interfaces in the material. However, the fine stru...Cold-drawn pearlitic steel wire is irreplaceably used in industry owing to its outstanding mechanical property which is dominated by the cementite/ferrite(Fe_(3)C/Fe) interfaces in the material. However, the fine structures of the Fe3C/Fe interfaces in the deformed wires are less known to date. In this work, transmission electron microscopic investigation was performed on the atomic structures of the interfaces with the Isaichev orientation relationship(OR) in the wires with progressive deformation strains. In addition to the effect of the dislocation/interface interactions, this work revealed that the deformation-induced partial decomposition of cementite plays an important role in the interface reconstruction during deformation. The interfacial carbon vacancies generated by cementite decomposition and particularly, the amorphization of cementite layers in the sample with ε > 1 could effectively annihilated the interfacial dislocations and consequently relaxed the interfacial stress. The correlations between the interface structure changes and the mechanical properties of the wires were discussed.展开更多
The proximal-based decomposition method was originally proposed by Chen and Teboulle （Math. Programming, 1994, 64：81-101 for solving corrvex minimization problems. This paper extends it to solving monotone variation...The proximal-based decomposition method was originally proposed by Chen and Teboulle （Math. Programming, 1994, 64：81-101 for solving corrvex minimization problems. This paper extends it to solving monotone variational inequalities associated with separable structures with the improvements that the restrictive assumptions on the involved parameters are much relaxed, and thus makes it practical to solve the subproblems easily. Without additional assumptions, global convergence of the new method is proved under the same mild assumptions on the problem＇s data as the original method.展开更多
Improving the thermal decomposition performance of hexanitrohexaazaisowurtzitane(CL-20)by appropriate methods is helpful to promote the combustion performance of CL-20-based solid propellants.In this study,we synthesi...Improving the thermal decomposition performance of hexanitrohexaazaisowurtzitane(CL-20)by appropriate methods is helpful to promote the combustion performance of CL-20-based solid propellants.In this study,we synthesized a sandwich structure of CL-20 and nanoporous carbon scaffolds film(NCS)and emphatically studied the thermal decomposition performance of the composite structure.Thermogravimetric analysis and differential scanning calorimetry were used to measure the thermal decomposition process of the composite structure.The kinetic parameters of thermal decomposition were calculated by the thermal dynamic analysis software AKTS.These results showed that the thermal decomposition performance of the sandwich structure of CL-20 and NCS was better than CL-20.Among the tested samples,NCS with a pore size of 15 nm had the best catalytic activity for the thermal decomposition of CL-20.Moreover,the thermal decomposition curve of the composite structure at the heating rate of 1 K/min was deconvoluted by mathematical method to study the thermal decomposition process.And a possible catalytic mechanism was proposed.The excellent thermal decomposition performance is due to the sandwich structure enhances the interface reaction of CL-20 and NCS.This work may promote the extensive use of CL-20 in the field of solid rocket propellant.展开更多
Two new energetic compounds(AIM)(HTNR)and(AIM)(PA)(AIM=2-azidoimidazole,TNR=2,4,6-trini troresorcinol,PA=picric acid)have been prepared by AIM(2-azidoimidazolium)and TNR(2,4,6-trinitroresorcinol)or PA(picric acid)and ...Two new energetic compounds(AIM)(HTNR)and(AIM)(PA)(AIM=2-azidoimidazole,TNR=2,4,6-trini troresorcinol,PA=picric acid)have been prepared by AIM(2-azidoimidazolium)and TNR(2,4,6-trinitroresorcinol)or PA(picric acid)and characterized by elemental analysis and FTIR spectrum.Their crystal structures were determined by X-ray single-crystal diffraction analysis.The obtained results show that(AIM)(HTNR)crystal belongs to monoc linic,P21/c space group,a=1.1306(2)nm,b=0.70305(14)nm,c=1.7398(4)nm,β=106.91°,V=1.3231(5)nm3,Dc=1.778 g/cm3,Z=4,R1=0.0524,wR2[I〉2σ(I)]=0.1067 and S=1.092 and(AIM)(PA)crystal belongs to monoclinic P21/c space group,a=0.80303(16)nm,b=0.81395(16)nm,c=2.0471(4)nm,β=93.93(3)°,V=1.3349(5)nm3,Dc=1.683 g/cm3,Z=4,R1=0.0784,wR2[I〉2σ(I)]=0.1814 and S=1.098.Both the compounds have electrostatic attraction and hy drogen bonds,which contribute to making the constructions more stable.The decomposition of the two compounds was studied via differential scanning calorimetry(DSC)and thermogravimetry-derivative thermogravimetry(TG-DTG)techniques at a heating rate of 10 oC/min,and the results show that both the compounds underwent one intensive exothermic decomposition stage.Sensitivity tests reveal that the title compounds were insensitive to friction and im pact and sensitive to flame and could be applied in potential pyrotechnics.展开更多
Structural health monitoring (SHM) is a relevant topic for civil systems and involves the monitoring, data processing and interpretation to evaluate the condition of a structure, in order to detect damage. In real str...Structural health monitoring (SHM) is a relevant topic for civil systems and involves the monitoring, data processing and interpretation to evaluate the condition of a structure, in order to detect damage. In real structures, two or more sites or types of damage can be present at the same time. It has been shown that one kind of damaged condition can interfere with the detection of another kind of damage, leading to an incorrect assessment about the structure condition. Identifying combined damage on structures still represents a challenge for condition monitoring, because the reliable identification of a combined damaged condition is a difficult task. Thus, this work presents a fusion of methodologies, where a single wavelet-packet and the empirical mode decomposition (EMD) method are combined with artificial neural networks (ANNs) for the automated and online identification-location of single or multiple-combined damage in a scaled model of a five-bay truss-type structure. Results showed that the proposed methodology is very efficient and reliable for identifying and locating the three kinds of damage, as well as their combinations. Therefore, this methodology could be applied to detection-location of damage in real truss-type structures, which would help to improve the characteristics and life span of real structures.展开更多
A new coordination complex [Cu（IMI）4]（PA）2 had been synthesized with imidazole（IMI） as ligands and picrate（PA-） groups as outer anions,and characterized by Fourier transform infrared（FTIR） spectrum and eleme...A new coordination complex [Cu（IMI）4]（PA）2 had been synthesized with imidazole（IMI） as ligands and picrate（PA-） groups as outer anions,and characterized by Fourier transform infrared（FTIR） spectrum and elemental analysis.Its crystal structure was determined by single crystal X-ray diffraction（XRD） analysis.The crystallographic data show that the crystal belongs to monoclinic,C2/c space group,a=2.542（5） nm,b=0.91773（18） nm,c=1.3778（3） nm,β=107.854（3）° and Z=4.Furthermore,the central copper（II） ion is coordinated by four N atoms from four imidazole ligands.All the molecular units are linked into a zigzag pattern along a-axis by the hydrogen bonds,and extended to the distance regularly.Thermal decomposition mechanisms were determined based on differential scanning calorimetry（DSC） and thermogravimetry-differential thermogravimetry（TG-DTG） analysis,and kinetic parameters of the first exothermic process were studied using Kissinger＇s and Ozawa-Doyle＇s method,respectively.Sensitivity tests show that the title complex has low sensitivity to external stimulus,but it has a higher energy of combustion of 14.2 kJ/g due to which it may be used as the additives of energetic materials to improve the explosive performance.展开更多
The title complex, Zn（C24H13NO）2Cl21, has been synthesized by the reaction of zinc chloride with Schiff base ligand N-salicylidene-p-toluidine and its structure was determined by single-crystal X-ray diffraction. Th...The title complex, Zn（C24H13NO）2Cl21, has been synthesized by the reaction of zinc chloride with Schiff base ligand N-salicylidene-p-toluidine and its structure was determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group Cc with a = 14.896（3）, b = 12.506（2）, c = 15.352（3） A,β = 114.711 （4）°, V = 2598.0（8） A^3, C28H26ZnCl2N2O2, Mr = 558.80, Z = 4, Dc = 1 .429 g/cm^3,μ = 1.179 mm^-1, Flack parameter = 0.027（19）, F（000） = 1152, R = 0.0709 and wR = 0.1041 for 3117 observed reflections （Ⅰ 〉 2σ（Ⅰ））. In complex 1, the center Zn ion is four-coordinated by two O atoms from two Schiff base ligands and two Cl atoms in a distorted tetrahedral geometry. Additionally, the thermal decomposition of complex 1 as well as its kinetic mechanisms and equations is studied under the non-isothermal integral and differential methods in air by TG-DTG curves.展开更多
A new energetic complex, Ni（3,4＇-Hbpt）2（Hoba）2（H20）2 （3,4＇-Hbpt = 3-（3-pyridyl）- 5-（4＇-pyridyl）-l-H-l,2,4-triazole and H2oba = 4,4＇-oxybis（benzoic acid））, has been synthesized by hydrothermal reactio...A new energetic complex, Ni（3,4＇-Hbpt）2（Hoba）2（H20）2 （3,4＇-Hbpt = 3-（3-pyridyl）- 5-（4＇-pyridyl）-l-H-l,2,4-triazole and H2oba = 4,4＇-oxybis（benzoic acid））, has been synthesized by hydrothermal reaction and characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, thermogravimetric analyses and X-ray powder diffraction. Single-crystal X-ray diffraction analysis indicates that the complex belongs to the monoclinic system, space group P2j/c with a = 10.2357（9）, b = 24.594（2）, c = 10.4225（9）/k, β = 114.0110（10）°, V = 2396.7（4） A3, Dc = 1.460 g/cm3,μ = 0.482 mm-1, Mr = 1053.63, F（000） = 1088, Z = 2, the final R = 0.0358 and wR = 0.0973 with I 〉 2σ（I）. Both 3,4＇-Hbpt and H2oba ligands adopt monodentate modes linking one Ni（II） ion to form a 0D motif. Furthermore, the 0D motifs are linked into a 3D supramolecular architecture with hydrogen bonds. In addition, the catalytic performance for thermal decomposition of the efficacy of ammonium perchlorate （AP） is explored by differential scanning calorimetry （DSC）, which indicates that the complex is a good candidate for a promoter of the thermal decomposition of ammonium perchlorate.展开更多
基金supported by the Universidad del Rosario(Small grant ID:IV-FPD003)。
文摘Upper Andean tropical forests are renowned for their extraordinary biodiversity and heterogeneous environmental conditions.Despite the critical role of litter decomposition in carbon and nutrient cycles,its dynamics in this region remains unexplored at finer scales.This study investigates how micro site conditions influence litter decomposition of 15 upper Andean species over time.A reciprocal translocation field experiment was conducted over 18 months in 14 permanent plots within four sites in Colombian Andean mountain forests.Each plot contained three litterbeds(microsites),each with the 15 species,harvested at 3,6,12 and 18 months,totaling 2520 litterbags.Different forest variables,including canopy openness,leaf area index,slope and depth of litter,were measured in each litterbed.ANOVAs and linear mixed models were used to assess variation between sites and plots respectively,while multiple linear regression analyses evaluated the effects of forest variables on decay rates over time at the micro site scale.Results showed differences in absolute decay rates between sites but consistent relative decay rates,indicating varying magnitudes of decomposition,yet maintaining the same order based on their litter quality.Decay rates varied between species,with more variation in labile species compared to recalcitrant ones.Despite substantial variation in forest characteristics within sites,their influence on litter decomposition was minimal and declined over time.This suggests that,at finer spatial scales,the forest microenvironment plays a lesser role in litter decomposition,with litter quality emerging as the primary driver.This study is a step towards understanding the fine-scale dynamics of litter decomposition in upper Andean tropical forests,highlighting the intricate interplay between microenvironmental factors and decomposition processes.
基金supported by the National Natural Science Foundation of China (Grant Nos.60772058 and 61271406)
文摘Underwater imaging posts a challenge due to the degradation by the absorption and scattering occurred during light propagation as well as poor lighting conditions in water medium Although image filtering techniques are utilized to improve image quality effectively, problems of the distortion of image details and the bias of color correction still exist in output images due to the complexity of image texture distribution. This paper proposes a new underwater image enhancement method based on image struc- tural decomposition. By introducing a curvature factor into the Mumford_Shah_G decomposition algorithm, image details and struc- ture components are better preserved without the gradient effect. Thus, histogram equalization and Retinex algorithms are applied in the decomposed structure component for global image enhancement and non-uniform brightness correction for gray level and the color images, then the optical absorption spectrum in water medium is incorporate to improve the color correction. Finally, the en- hauced structure and preserved detail component are re.composed to generate the output. Experiments with real underwater images verify the image improvement by the proposed method in image contrast, brightness and color fidelity.
文摘The structural damage identification through modal data often leads to solving a set of linear equations. Special numerical treatment is sometimes required for an accurate and stable solution owing to the ill conditioning of the equations. Based on the singular value decomposition (SVD) of the coefficient matrix, an error based truncation algorithm is proposed in this paper. By rejection of selected small singular values, the influence of noise can be reduced. A simply-supported beam is used as a simulation example to compare the results to other methods. Illustrative numerical examples demonstrate the good efficiency and stability of the algorithm in the nondestructive identification of structural damage through modal data.
基金Project(2012GK2025)supported by Science-Technology Plan Foundation of Hunan Province,ChinaProject(2013zzts039)supported by the Fundamental Research Funds for Central South University,China
文摘A hierarchical structural decomposition analysis(SDA) model has been developed based on process-level input-output(I-O) tables to analyze the drivers of energy consumption changes in an integrated steel plant during 2011-2013. By combining the principle of hierarchical decomposition into D&L method, a hierarchical decomposition model for multilevel SDA is obtained. The developed hierarchical IO-SDA model would provide consistent results and need less computation effort compared with the traditional SDA model. The decomposition results of the steel plant suggest that the technology improvement and reduced steel final demand are two major reasons for declined total energy consumption. The technical improvements of blast furnaces, basic oxygen furnaces, the power plant and the by-products utilization level have contributed mostly in reducing energy consumption. A major retrofit of ancillary process units and solving fuel substitution problem in the sinter plant and blast furnace are important for further energy saving. Besides the empirical results, this work also discussed that why and how hierarchical SDA can be applied in a process-level decomposition analysis of aggregated indicators.
基金Supported by Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA05150600)National Natural Science Foundation of China (No. 71273027 and No. 70903066)Beijing Planning Office of Philosophy and Social Science (No. 11JGC105)
文摘As China's energy intensity fluctuated in recent years, it is necessary to examine whether this fluctuation happened at a regional level. This paper establishes a decomposition model by using the structural decomposition analysis (SDA) method at a regional level. Then this model is employed to empirically analyze the changes of Beijing's energy intensity. The conclusions are as follows: during 2002-2010, except petroleum, the energy intensity decreased and the changes were mostly attributed to the technology changes, while the final use variation actually increased the energy intensity; comparing different periods of 2002-2010, the decline rates of energy intensity for coal and hydropower were decreasing, resulting from the production technology being more energy-intensive than before; the energy intensity changes of petroleum firstly increased substantially and then decreased moderately.
基金National Natural Science Foundation of China, No.41501144 National Key Research and Development Program, No.2016YFA0602801+2 种基金 Guangdong Academy of Sciences Youth Science Foundation, No.qn.ij201501 High-level Leading Talent Introduction Program of GDAS, No.2016GDASRC-0101 Scientific Platform and Innovation Capability Construction Program of GDAS, No.2016GDASPT-0210.
文摘Analysis of carbon emission mechanism based on regional perspectives is an im- portant research method capable of achieving energy savings and emission reductions. Xin- jiang, an important Chinese energy production base, is currently going through a period of strategic opportunities for rapid development. Ensuring stable socio-economic development while achieving energy savings and meeting emission reductions targets, is the key issue currently facing the region. This paper is based on the input-output theory, and conducts a structural decomposition analysis on the factors affecting energy-related carbon emissions in Xinjiang from 1997 to 2007; this analysis employs a hybrid input-output analysis framework of ＂energy - economy - carbon emissions＂. （1） Xinjiang＇s carbon emissions from energy con- sumption increased from 20.70 million tons in 1997 to 40.34 million tons in 2007; carbon emissions growth was mainly concentrated in the production and processing of energy re- sources, the mining of mineral resources, and the processing industry. （2） The analysis of the direct effects of the influencing factors on carbon emissions showed that the change in per capita GDP, the final demand structure, the population scale, and the production structure were the important factors causing an increase in carbon emissions, while the decrease in carbon emission intensity during this period was the important influencing factor in stopping the growth of carbon emissions. This showed that while the sizes of Xinjiang＇s economy and population were growing, the economic structure had not been effectively optimized and the production technology had not been efficiently improved, resulting in a rapid growth of carbon emissions from energy consumption. （3） The analysis of the indirect effects of the influencing factors of carbon emission showed that the inter-provincial export, fixed capital formation, and the consumption by urban residents had significant influence on the changes in carbon emissions from energy consumption in Xinjiang. （4） The growth of investments in fixed assets of carbon intensive industry sectors, in addition to the growth of inter-provincial exports ofenergy resource products, makes the transfer effect of inter-provincial ＂embodied carbon＂ very significant.
文摘Eleven rare earth salts of 3-nitro-1, 2 , 4-triazol-5-one (NTO) was prepared by using aqueous solutions of lithium salt of NTO and corresponding rare earth nitrates. The formulae of these salts are determined as RE(NTO)3. nH2O, where RE is Y, La, Ce, Pr, Nd, Sm, Eu, Gd,Tb, Dy or Yb, and n is 6, 7, 7, 7, 8, 7, 7, 7, 5, 5 and 6 correspondingly. Their thermal decomposition mechanism was studied by using DSC, TG-DTG and FT-IR techniques under linearly increasing temperature.
文摘This paper presents a brief description of the software toolbox, linear systems toolkit, developed in Matlab environment. The toolkit contains 66 m-functious, including structural decompositions of linear autonomous systems, unforced/uuseused systems, proper systems, and singular systems, along with their applications to system factorizations, sensor/actuator selection, H-two and H-infinity control, and disturbance decoupling problems.
基金This work was supported by the the National Nat-ural Science Foundation of China(No.21773011 and No.21373033).
文摘Alkyl dinitrites have at-tracted attention as an im-portant type of nitrosating agent and a pollution source in atmosphere.The reac-tivity and chemistry of alkyl dinitrites induced by the two ONO functional groups are relatively unknown.In this work,decompositions of 1,3-cyclohexane dinitrite and 1,4-cyclohexane dinitrite are studied by electron impact ionization mass spectroscopy(EI-MS).Apart from NO^(+)(m=z=30),fragment ions m=z=43 and 71 are the most abundant for the 1,3-isomer.On the other hand,fragments m=z=29,57,85,and 97 stand out in the EI-MS spectrum of 1,4-isomer.Possible dissociation mechanisms of the two dinitrites are proposed by theoretical calculations.The results reveal that the ring-opening of 1,3-cyclohexane dinitrite mainly starts from the intermediate ion(M-NO)^(+)by cleavage of twoαC-βC bonds.For 1,4-cyclohexane dinitrite,in addition to the decomposition via intermediate(M-NO)^(+),cleavage ofβC-βC bonds can occur directly from the parent cation(M)^(+).The results will help to understand the structural related chemistry of alkyl dinitrites in atmosphere and in NO transfer process.
基金supported by the National Natural Science Foundation of China (Grant No.71463057)the Young Innovative Talent Training Project of Xinjiang Uygur Autonomous Region (Grant No. 2013731005)+1 种基金the Natural Science Foundation of Xinjiang Uygur Autonomous Region (Grant No. 2012211B02)the Humanities and Social Science Project of Ministry of Education of China (Grant No. 11YJC790148)
文摘In order to find the dominant factor of energy efficiency change, this paper uses the modified structural model to analyze energy efficiency change from 1990 to 2012 in Xinjiang. The result shows that the energy efficiency increase is largely due to energy technological innovation especially by the industrial sector, and the contribution from structural shift is limited. Therefore, we should vigorously support energy-saving technological progress in the industrial sector and develop the modern service industries with lower energy consumption, in order to realize the goal of improving energy efficiency.
文摘Three complexes, [Pr（NO3）3（HL）2] （1）, [Nd（NO3）3（HL）2] （2） and [Er（NO3）3（HL）2] ·0.5H2O （3）, were synthesized from the reaction of a Schiff base ligand 2-[ （4-methylphenylimino）methyl ]-6-methoxyphenol （C15 H15 NO2, HL） with Ln（NO3）3·6H2O （Ln = Pr, Nd, Er）. Characterization by single-crystal X-ray diffraction technique, elemental analysis, molar conductance, FT-IR, UV-Vis, ^1H NMR and thermal analysis shows the title complexes are neutral molecules where the central Ln（ Ⅲ） ion is ten-coordinated in biapical anti-hexahedron prism geometry, with four oxygen atoms of the phenolic hydroxy and methoxy groups in the two bidentate Schiff base ligands and six oxygen atoms provided by the three bidentate NO3 - anions. Additionally, the kinetic mechanism of thermal decomposition of complex 3 was determined with a TG-DTG curves by both integral and differential methods. The functions of thermal decomposition reaction mechanism and the equation of kinetic compensation effect were obtained.
基金supported by the National Natural Science Foundation of China(No.21243007)National Defense Fundamental Scientific Research(No.B09201100051)
文摘A new energetic organic potassium salt bis（dinitromethyl）difurazanyl ether potas- sium salt [K2（BDFE）] was synthesized, and structurally characterized by elemental analysis, IR spectra, t3C NMR and single-crystal X-ray diffraction. K2（BDFE） crystallizes in monoclinic system, space group C2/c with a = 17.342（3）, b = 12.6943（17）, c = 8.0972（11） A, β = 110.630（2）°, V = 1668.3（4） A3, Z = 4, Dc = 2.000 g/cm3, F（000） = 1000,μ= 0.675 mm-1, S = 1.058, the final R = 0.0499 and wR = 0.1452. The K ion is eight-coordinated with eight O atoms from one water molecule and four bis（dinitromethyl）difurazanyl ethers （BDFE）, forming a distorted dodecahedral structure. Thermal decomposition of the title complex was studied by using DSC and TG-DTG. There are primarily two exothermic decomposition processes between 200 and 370 ℃.
基金financially supported by the National Natural Science Foundation of China (No. 51501195)the Fund of SYNL。
文摘Cold-drawn pearlitic steel wire is irreplaceably used in industry owing to its outstanding mechanical property which is dominated by the cementite/ferrite(Fe_(3)C/Fe) interfaces in the material. However, the fine structures of the Fe3C/Fe interfaces in the deformed wires are less known to date. In this work, transmission electron microscopic investigation was performed on the atomic structures of the interfaces with the Isaichev orientation relationship(OR) in the wires with progressive deformation strains. In addition to the effect of the dislocation/interface interactions, this work revealed that the deformation-induced partial decomposition of cementite plays an important role in the interface reconstruction during deformation. The interfacial carbon vacancies generated by cementite decomposition and particularly, the amorphization of cementite layers in the sample with ε > 1 could effectively annihilated the interfacial dislocations and consequently relaxed the interfacial stress. The correlations between the interface structure changes and the mechanical properties of the wires were discussed.
基金the National Natural Science Foundation of China(No.70671024)the Na-tional High-Tech Research and Development Program of China(863 Program)(No.2006AA11Z209)
文摘The proximal-based decomposition method was originally proposed by Chen and Teboulle （Math. Programming, 1994, 64：81-101 for solving corrvex minimization problems. This paper extends it to solving monotone variational inequalities associated with separable structures with the improvements that the restrictive assumptions on the involved parameters are much relaxed, and thus makes it practical to solve the subproblems easily. Without additional assumptions, global convergence of the new method is proved under the same mild assumptions on the problem＇s data as the original method.
基金supported by the National Natural Science Foundation of China(No:21975227)the Shanxi Province Graduate Student Innovation Project(No:2020SY403)。
文摘Improving the thermal decomposition performance of hexanitrohexaazaisowurtzitane(CL-20)by appropriate methods is helpful to promote the combustion performance of CL-20-based solid propellants.In this study,we synthesized a sandwich structure of CL-20 and nanoporous carbon scaffolds film(NCS)and emphatically studied the thermal decomposition performance of the composite structure.Thermogravimetric analysis and differential scanning calorimetry were used to measure the thermal decomposition process of the composite structure.The kinetic parameters of thermal decomposition were calculated by the thermal dynamic analysis software AKTS.These results showed that the thermal decomposition performance of the sandwich structure of CL-20 and NCS was better than CL-20.Among the tested samples,NCS with a pore size of 15 nm had the best catalytic activity for the thermal decomposition of CL-20.Moreover,the thermal decomposition curve of the composite structure at the heating rate of 1 K/min was deconvoluted by mathematical method to study the thermal decomposition process.And a possible catalytic mechanism was proposed.The excellent thermal decomposition performance is due to the sandwich structure enhances the interface reaction of CL-20 and NCS.This work may promote the extensive use of CL-20 in the field of solid rocket propellant.
基金Supported by the Program for New Century Excellent Talents in Universities of China(No.NCET-10-0051)the Exploration Foundation of State Key Laboratory of Explosion Science and Technology,China(No.YBKT10-05)+1 种基金the Key Support Foundation of State Key Laboratory of Explosion Science and Technology,China(No.ZDKT10-01b)the Science and Technology Fund on Applied Physical Chemistry Laboratory(No.9140C3703051105)
文摘Two new energetic compounds(AIM)(HTNR)and(AIM)(PA)(AIM=2-azidoimidazole,TNR=2,4,6-trini troresorcinol,PA=picric acid)have been prepared by AIM(2-azidoimidazolium)and TNR(2,4,6-trinitroresorcinol)or PA(picric acid)and characterized by elemental analysis and FTIR spectrum.Their crystal structures were determined by X-ray single-crystal diffraction analysis.The obtained results show that(AIM)(HTNR)crystal belongs to monoc linic,P21/c space group,a=1.1306(2)nm,b=0.70305(14)nm,c=1.7398(4)nm,β=106.91°,V=1.3231(5)nm3,Dc=1.778 g/cm3,Z=4,R1=0.0524,wR2[I〉2σ(I)]=0.1067 and S=1.092 and(AIM)(PA)crystal belongs to monoclinic P21/c space group,a=0.80303(16)nm,b=0.81395(16)nm,c=2.0471(4)nm,β=93.93(3)°,V=1.3349(5)nm3,Dc=1.683 g/cm3,Z=4,R1=0.0784,wR2[I〉2σ(I)]=0.1814 and S=1.098.Both the compounds have electrostatic attraction and hy drogen bonds,which contribute to making the constructions more stable.The decomposition of the two compounds was studied via differential scanning calorimetry(DSC)and thermogravimetry-derivative thermogravimetry(TG-DTG)techniques at a heating rate of 10 oC/min,and the results show that both the compounds underwent one intensive exothermic decomposition stage.Sensitivity tests reveal that the title compounds were insensitive to friction and im pact and sensitive to flame and could be applied in potential pyrotechnics.
基金Project (No. PIFI-2012 U. de Gto.) supported by the Secretariat of Public Education (SEP), Mexico
文摘Structural health monitoring (SHM) is a relevant topic for civil systems and involves the monitoring, data processing and interpretation to evaluate the condition of a structure, in order to detect damage. In real structures, two or more sites or types of damage can be present at the same time. It has been shown that one kind of damaged condition can interfere with the detection of another kind of damage, leading to an incorrect assessment about the structure condition. Identifying combined damage on structures still represents a challenge for condition monitoring, because the reliable identification of a combined damaged condition is a difficult task. Thus, this work presents a fusion of methodologies, where a single wavelet-packet and the empirical mode decomposition (EMD) method are combined with artificial neural networks (ANNs) for the automated and online identification-location of single or multiple-combined damage in a scaled model of a five-bay truss-type structure. Results showed that the proposed methodology is very efficient and reliable for identifying and locating the three kinds of damage, as well as their combinations. Therefore, this methodology could be applied to detection-location of damage in real truss-type structures, which would help to improve the characteristics and life span of real structures.
基金Supported by the Project of Science and Technology of Applied Physical Chemistry Laboratory of China(No.9140C3703051105)the Project of State Key Laboratory of Explosion Science and Technology,China(Nos. QNKT12-02,ZDKT10-01b)
文摘A new coordination complex [Cu（IMI）4]（PA）2 had been synthesized with imidazole（IMI） as ligands and picrate（PA-） groups as outer anions,and characterized by Fourier transform infrared（FTIR） spectrum and elemental analysis.Its crystal structure was determined by single crystal X-ray diffraction（XRD） analysis.The crystallographic data show that the crystal belongs to monoclinic,C2/c space group,a=2.542（5） nm,b=0.91773（18） nm,c=1.3778（3） nm,β=107.854（3）° and Z=4.Furthermore,the central copper（II） ion is coordinated by four N atoms from four imidazole ligands.All the molecular units are linked into a zigzag pattern along a-axis by the hydrogen bonds,and extended to the distance regularly.Thermal decomposition mechanisms were determined based on differential scanning calorimetry（DSC） and thermogravimetry-differential thermogravimetry（TG-DTG） analysis,and kinetic parameters of the first exothermic process were studied using Kissinger＇s and Ozawa-Doyle＇s method,respectively.Sensitivity tests show that the title complex has low sensitivity to external stimulus,but it has a higher energy of combustion of 14.2 kJ/g due to which it may be used as the additives of energetic materials to improve the explosive performance.
文摘The title complex, Zn（C24H13NO）2Cl21, has been synthesized by the reaction of zinc chloride with Schiff base ligand N-salicylidene-p-toluidine and its structure was determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group Cc with a = 14.896（3）, b = 12.506（2）, c = 15.352（3） A,β = 114.711 （4）°, V = 2598.0（8） A^3, C28H26ZnCl2N2O2, Mr = 558.80, Z = 4, Dc = 1 .429 g/cm^3,μ = 1.179 mm^-1, Flack parameter = 0.027（19）, F（000） = 1152, R = 0.0709 and wR = 0.1041 for 3117 observed reflections （Ⅰ 〉 2σ（Ⅰ））. In complex 1, the center Zn ion is four-coordinated by two O atoms from two Schiff base ligands and two Cl atoms in a distorted tetrahedral geometry. Additionally, the thermal decomposition of complex 1 as well as its kinetic mechanisms and equations is studied under the non-isothermal integral and differential methods in air by TG-DTG curves.
基金Supported by the National Natural Science Foundation of China(No.21263019)
文摘A new energetic complex, Ni（3,4＇-Hbpt）2（Hoba）2（H20）2 （3,4＇-Hbpt = 3-（3-pyridyl）- 5-（4＇-pyridyl）-l-H-l,2,4-triazole and H2oba = 4,4＇-oxybis（benzoic acid））, has been synthesized by hydrothermal reaction and characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, thermogravimetric analyses and X-ray powder diffraction. Single-crystal X-ray diffraction analysis indicates that the complex belongs to the monoclinic system, space group P2j/c with a = 10.2357（9）, b = 24.594（2）, c = 10.4225（9）/k, β = 114.0110（10）°, V = 2396.7（4） A3, Dc = 1.460 g/cm3,μ = 0.482 mm-1, Mr = 1053.63, F（000） = 1088, Z = 2, the final R = 0.0358 and wR = 0.0973 with I 〉 2σ（I）. Both 3,4＇-Hbpt and H2oba ligands adopt monodentate modes linking one Ni（II） ion to form a 0D motif. Furthermore, the 0D motifs are linked into a 3D supramolecular architecture with hydrogen bonds. In addition, the catalytic performance for thermal decomposition of the efficacy of ammonium perchlorate （AP） is explored by differential scanning calorimetry （DSC）, which indicates that the complex is a good candidate for a promoter of the thermal decomposition of ammonium perchlorate.
