Acrylonitrile-butadiene-Styrene (ABS), with and without calcium carbonate (calcite) particles,was used as the matrix for reinforcement with as-received short-glass fibres (were originallytreated by the manufacturer) a...Acrylonitrile-butadiene-Styrene (ABS), with and without calcium carbonate (calcite) particles,was used as the matrix for reinforcement with as-received short-glass fibres (were originallytreated by the manufacturer) and sized short-glass fibres with two amino-silane coupling agents.The calcite particle content is 0, 11.7 and 23.5 vol. pct for the matrices. The glass fiber contentis 0, 10 and 15 vol. pct. The matrix materials and corresponding composites were compoundedusing a twin screw extruder and dumbbell-shaped tensile bars were prepared with an injectionmolding process. The tensile and flexural properties as well as the unnotched and notchedCharpy impact energies of short glass fibre/calcite/ABS composites were studied in this paper.The effects of fibres, fibre surface treatments and particles on these mechanical properties ofthe composites were discussed in detail. An importarit information was obtained, which is thatthe tensile and flexural strengths of hybrid SGF/calcite/ABS composites are the same as thoseof corresponding fibre composites when the ratio of the interfacial adhesion strength betweenparticles and matrix to that between fibres and matrix is higher than certain value. otherwise theformer are lower than the latter.展开更多
The difference analysis of physical-mechanical properties of muddy sediments is made in the central South Yellow Sea and the Zhe-Min（Zhejiang Province to Fujian Province of China） coastal area. The results show that...The difference analysis of physical-mechanical properties of muddy sediments is made in the central South Yellow Sea and the Zhe-Min（Zhejiang Province to Fujian Province of China） coastal area. The results show that sediments in the two regions are both dominated by mud. There are perfect negative power function correlations between the water content and the density, the compression coefficient and the compression modulus; a good positive power function correlation between the liquid limit and the plastic limit, a perfect positive linear correlation between the water content and the void ratio, and a perfect polynomial function correlation between the miniature vane shear strength and the pocket penetration resistance. In general, compared with sediments in the Zhe-Min coastal area, sediments in the central South Yellow Sea possess high water content, high void ratio,low density, high plasticity, high compressibility, low shear strength. The causes of the differences between physical-mechanical properties of sediments are analyzed from the topographic features, material sources,hydrodynamic conditions, deposition rate, and material composition. Compared with the Zhe-Min coastal area,the central South Yellow Sea is far from the Mainland and low-lying; has poor hydrodynamic condition; the materials diffused to the area are less and dominated by fine clay, have the high content of smectite and organic matters. These factors lead to sediments of the central South Yellow Sea has the higher water content, the higher plasticity, the lower density, and the lower strength than sediments in the Zhe-Min coastal area.展开更多
A new copper complex 2{Cu（C10H8N2）[C8H11O2（COO）]（H2O）3}·（H2O）5 with bicycle[2.2.1]hept-2-en-5,6-dicarboxylic acid（H2L） [C7H8（COOH）2], basic copper carbonate and 2,2＇-bipyridine has been synthesized i...A new copper complex 2{Cu（C10H8N2）[C8H11O2（COO）]（H2O）3}·（H2O）5 with bicycle[2.2.1]hept-2-en-5,6-dicarboxylic acid（H2L） [C7H8（COOH）2], basic copper carbonate and 2,2＇-bipyridine has been synthesized in the mixed solvents of methanol and water. It crystallizes in the triclinic system, space group P1, with a = 7.4626（5）, b = 11.9779（8）, c = 12.9841（8）A, α = 109.7040（10）, β = 98.7550（10）, γ = 90.6240（10）°, V = 1077.50（12）A3, Dc = 1.538 g/cm^3, Z = 1, F（000） = 520, GOOF = 1.065, R = 0.0360 and wR = 0.0950. The copper ion is coordinated with four oxygen atoms from one H2 L molecule and three water molecules together with two nitrogen atoms from the 2,2＇-bipyridine molecule, forming a distorted octahedral coordination geometry. The thermal stability and electrochemical properties were also studied.展开更多
A one-dimensional chain coordination polymer [Cu（phen）（2,4,6-TMBA）2（H2O）]n has been synthesized by reacting 2,4,6-trimethyl-benzoic acid, 1,10-phenanthroline and Cu（Ⅱ） perchlorate and its structure was charac...A one-dimensional chain coordination polymer [Cu（phen）（2,4,6-TMBA）2（H2O）]n has been synthesized by reacting 2,4,6-trimethyl-benzoic acid, 1,10-phenanthroline and Cu（Ⅱ） perchlorate and its structure was characterized. Crystal data for this complex： tetragonal, space group I41, a = 2.0293（3）, b = 2.0293（3）, c = 1.3758（2） nm, α =β= γ = 90°, V= 5.6657（13） nm3, Dc= 1.379 g/cm3, Z = 8, μ（MoKa） = 0.815 mm-1, Mr = 588.14, F（000） = 2456, S = 1.047, R = 0.0459 and wR = 0.1053. The crystal structure shows that two neighboring Cu（Ⅱ） ions are linked together by one bridging-chelating 2,4,6-trimethyl-benzoic group, forming a one-dimensional chain structure. Each Cu（Ⅱ） ion is coordinated with two nitrogen atoms from one 1,10-phenanthroline molecule, three oxygen atoms from three 2,4,6-trimethyl-benzoic acid molecules and one oxygen atom from one water molecule, giving a six-coordinate distorted octahedral coordination geometry. The cyclic voltammetry behavior of the complex was also investigated.展开更多
A novel one-dimensional chain coordination polymer [Mn（NAAh（4,4′-bipy）（H2O）4], has been synthesized with a-naphthaleneacetic acid, 4,4′-bipy and manganese（Ⅱ） sulfate as raw materials. Crystal data for this c...A novel one-dimensional chain coordination polymer [Mn（NAAh（4,4′-bipy）（H2O）4], has been synthesized with a-naphthaleneacetic acid, 4,4′-bipy and manganese（Ⅱ） sulfate as raw materials. Crystal data for this complex： monoclinic, space group P21/c, a = 1.1421（2）, b = 1.6337（3）, c = 0.94177（19） nm, β = 112.15（3）°, V = 1.6275（6） nm^3, De = 1.407 g/cm^3, Z = 2, μ（MoKa） = 0.467 mm^-1, F（000） = 722, S = 1.007, R= 0.0412 and wR = 0.1022. The crystal structure shows that two neighboring manganese（Ⅱ） ions are linked together by one 4,4′-bipy molecule, and the whole complex molecule forms a one-dimensional chain structure. Each manganese（Ⅱ） ion is coordinated with two oxygen atoms of two a-naphthaleneacetic acid molecules, two nitrogen atoms of two 4,4′-bipy molecules and two oxygen atoms from two water molecules, giving a distorted octahedral coordination geometry. The electrochemical properties were also analyzed.展开更多
A new cadmium complex [Cd（phen）3]·（ClO4）2·（α-FRA）-（H2O）3 was prepared by self-assembly of α-furoic acid, 1,10-phenanthroline （phen）, and cadmium perchlorate. It crystallizes in the monoclinic sys...A new cadmium complex [Cd（phen）3]·（ClO4）2·（α-FRA）-（H2O）3 was prepared by self-assembly of α-furoic acid, 1,10-phenanthroline （phen）, and cadmium perchlorate. It crystallizes in the monoclinic system, space group P21/n, with a = 1.28130（15）, b = 2.5957（3）, c = 1.35449（16） nm, β = 109.395（2）°, V = 4.2492（9） nm^3, Dc = 1.491 g/cm^3, Z = 4, F（000） = 1926, GOOF = 1.023, the final R = 0.0729 and wR = 0.2086. The crystal structure analysis indicates that the cadmium ion is coordinated with six nitrogen atoms from six 1,10-phenanthroline molecules, giving a distorted octahedral coordination geometry. The cyclic voltametric behavior of the complex was also investigated.展开更多
One new cadmium complex [Cd（phen）3]·（ClO4）2·（p-MBA）2·（H2O）2 has been hydrothermally synthesized by reacting p-methylbenzoic acid （p-MBA）, 1,10-phenanthroline （phen） and cadmium perchlorate. ...One new cadmium complex [Cd（phen）3]·（ClO4）2·（p-MBA）2·（H2O）2 has been hydrothermally synthesized by reacting p-methylbenzoic acid （p-MBA）, 1,10-phenanthroline （phen） and cadmium perchlorate. It crystallizes in the triclinic system, space group P1, with a = 1.2809（3）, b = 1.3431（3）, c = 1.3734（3） nm, α = 84.259（4）, β = 71.603（3）, γ = 74.424（3）°, V= 2.1594（8） nm3, Do = 1.532 g/cm3, Z = 2, F（000） = 1008, μ= 0.697 mm^-1, R = 0.0646 and wR = 0.1648. The crystal structure shows that the cadmium ion is coordinated with six nitrogen atoms from three 1,10-phenanthroline molecules, forming a distorted octahedral coordination geometry. The result of electrochemical property analysis shows that the electron transfer in the electrode reaction is irreversible.展开更多
For the handling, treatment and utilization of fly ash from biomass combustion its chemical composition and physical properties are important. In this study eight filter fly ashes from different grate-fired biomass co...For the handling, treatment and utilization of fly ash from biomass combustion its chemical composition and physical properties are important. In this study eight filter fly ashes from different grate-fired biomass combustion plants were investigated. In fly ash from straw combustion high concentrations of（K） were found, whereas in the fly ash from wood combustion the concentrations of Ca and Mg were higher. The average concentration of PO3-4was similar in both types of fly ashes. In all wood fly ashes some measured heavy metal concentrations were above the limits for utilization. The straw fly ashes were much less contaminated and can be utilized. For wood fly ash most parameters showed little variation, except from one fly ash where the dust pre-separator is in poor condition. The average values were： mass median diameter 4.3 ± 0.8 μm, spread of particle size distribution19 ± 11, particle density 2620 ± 80 kg/m^3 and angle of repose 50°± 1°. The density of the straw fly ashes is lower（2260 ± 80 kg/m^3） and the spread of the size distribution is higher（72 ± 24）.For one straw combustion fly ash the values of the mass median diameter and the angle of repose were similar to the values of wood combustion fly ash, for the other straw fly ash the values differed considerably. While the particle size of this fly ash was much smaller,surprisingly the angle of repose was also lower. This can be attributed to the formation of small agglomerates in this fly ash, which were not disintegrated without a certain stress.展开更多
Bistatic forward-looking synthetic aperture radar（SAR） has many advantages and applications owing to its twodimensional imaging capability.There could be various imaging configurations because of the geometric flexi...Bistatic forward-looking synthetic aperture radar（SAR） has many advantages and applications owing to its twodimensional imaging capability.There could be various imaging configurations because of the geometric flexibility of bistatic platforms,resulting in kinds of models built independently among which there could be some similar even the same motion features.Comprehensive research on such systems in a more comprehensive and general point of view is required to address their difference and consistency.Property analysis of bistatic forwardlooking SAR with arbitrary geometry is achieved including stripmap and spotlight modes on airborne platform,missile-borne platform,and hybrid platform of both.Emphasis is placed on azimuth space variance of some key parameters significantly affecting the subsequent imaging processing,based on which the frequency spectra are further described and compared considering respective features of different platforms for frequency imaging algorithm developing.Simulation results confirm the effectiveness and correctness of our analysis.展开更多
In open-pit mines,pit slope as one of the important parameters affects the mine economy and total minable reserve,and it is also affected by different uncertainties which arising from many sources.One of the most crit...In open-pit mines,pit slope as one of the important parameters affects the mine economy and total minable reserve,and it is also affected by different uncertainties which arising from many sources.One of the most critical sources of uncertainty effects on the pit slope design is rock mass geomechanical properties.By comparing the probability of failure resulted from deterministic procedure and probabilistic one,this paper investigated the effects of aforesaid uncertainties on open-pit slope stability in metal mines.In this way,to reduce the effect of variance,it implemented Latin Hypercube Sampling(LHS)technique.Furthermore,a hypothesis test was exerted to compare the effects on two cases in Middle East.Subsequently,the investigation approved high influence of geomechanical uncertainties on overall pit steepness and stability in both iron and copper mines,though on the first case the effects were just over.展开更多
Discrete models such as the lumped parameter model and the finite element model are widely used in the solution of soil amplification of earthquakes. However, neither of the models will accurately estimate the natural...Discrete models such as the lumped parameter model and the finite element model are widely used in the solution of soil amplification of earthquakes. However, neither of the models will accurately estimate the natural frequencies of soil deposit, nor simulate a damping of frequency independence. This research develops a new discrete model for onedimensional viscoelastic response analysis of layered soil deposit based on the mode equivalence method. The new discrete model is a one-dimensional equivalent multi-degree-of-freedom（MDOF） system characterized by a series of concentrated masses, springs and dashpots with a special configuration. The dynamic response of the equivalent MDOF system is analytically derived and the physical parameters are formulated in terms of modal properties. The equivalent MDOF system is verified through a comparison of amplification functions with the available theoretical solutions. The appropriate number of degrees of freedom（DOFs） in the equivalent MDOF system is estimated. A comparative study of the equivalent MDOF system with the existing discrete models is performed. It is shown that the proposed equivalent MDOF system can exactly present the natural frequencies and the hysteretic damping of soil deposits and provide more accurate results with fewer DOFs.展开更多
Recycled ceramic mixed sand（RCMS） was obtained by partially replacing ultra-fine sand with recycled ceramic coarse sand（RCCS）. The effects of RCCS replacement rate on the apparent density, workability, compressive...Recycled ceramic mixed sand（RCMS） was obtained by partially replacing ultra-fine sand with recycled ceramic coarse sand（RCCS）. The effects of RCCS replacement rate on the apparent density, workability, compressive strength and splitting tensile strength of recycled ceramic concrete（RCC） were investigated. In addition, the relationship between the water-cement ratio and compressive strength of RCC was also studied. The experimental results indicate that the reusing of recycled ceramic aggregate can improve the cohesiveness and water retentiveness of fresh concrete and benefit the mechanical properties development. When the RCCS replacement rate is not less than 40%, the mechanical properties of RCC are superior to those of the reference concrete. Moreover, when recycled ceramic medium sand was completely used as fine aggregate, the maximum increase in both compressive strength and splitting tensile strength were obtained, comparing with those of reference concrete, the increment ratio was 19.85% and 32.73%, respectively. The microscopic analysis shows that the using of recycled ceramic aggregate can meliorate distinctly the structure of the interfacial transition zone（ITZ） and increase the compaction degree of cement paste. Furthermore, an expression of the compressive strength of RCC and the cement-water ratio is regressed and gains a good linear relativity. It is an effective way to recycle waste ceramic, and the consumption of recycled ceramic aggregate could reach from 26.9% to 47.6% of the total weight of aggregate in producing concrete.展开更多
Influence of the gassing materials, such as PA6, PMMA, and POM on the dielectric properties of air are investigated. In this work, the fundamental electron collision cross section data were carefully selected and vali...Influence of the gassing materials, such as PA6, PMMA, and POM on the dielectric properties of air are investigated. In this work, the fundamental electron collision cross section data were carefully selected and validated. Then the species compositions of the air–organic vapor mixtures were calculated based on the Gibbs free energy minimization. Finally, the Townsend ionization coefficient, the Townsend electron attachment coefficient and the critical reduced electric field strength were derived from the calculated electron energy distribution function by solving the Boltzmann transport equation. The calculation results indicated that H;O with large attachment cross sections has a great impact on the critical reduced electric field strength of the air–organic vapor mixtures. On the other hand, the vaporization of gassing materials can help to increase the dielectric properties of air circuit breakers to some degree.展开更多
Nd Sr2Mn2O7＋δ compounds were synthesized by ceramic method under three different cooling conditions. The Nd Sr2Mn2O7＋δ samples were characterized by powder X-ray diffraction（XRD）. Oxygen non-stoichiometry data f...Nd Sr2Mn2O7＋δ compounds were synthesized by ceramic method under three different cooling conditions. The Nd Sr2Mn2O7＋δ samples were characterized by powder X-ray diffraction（XRD）. Oxygen non-stoichiometry data for the studied powders were determined by using gravimetric and X-ray photoelectron spectroscopy（XPS） methods. The correlation of cooling method and oxygen as non-stoichiometry was established. The electroconductivity in samples was studied by using four-point probe method, and the strong correlation with non-stoichiometry was found out. Magnetization measurements were carried out. It was found that the magnetic and transport properties of the samples were also influenced by oxygen non-stoichiometry. The evolution of the magnetic properties could be explained by the formation of magnetic clusters in the vicinity of oxygen vacancies（OV） and strong competition between the superexchange and double exchange interactions.展开更多
This research aims to investigate the effect of pulsed Nd：YAG laser micro-welding on the microstructure,texture and magnetic properties of ultra-thin Fe-Co-7.15 wt%V magnetic alloy.Optical microscopy,scanning electro...This research aims to investigate the effect of pulsed Nd：YAG laser micro-welding on the microstructure,texture and magnetic properties of ultra-thin Fe-Co-7.15 wt%V magnetic alloy.Optical microscopy,scanning electron microscopy and electron backscattered diffraction techniques were used to study the microstructural evolutions.Also,vibrating sample magnetometry was used to characterize the magnetic properties.The results showed that the fractions of low Σ coincidence site lattice boundaries in the fusion zone are higher than those of the base metal.The welded samples experience a significant decrease in their magnetic properties.It was found that the formation of new fiber texture in the fusion zone and grain coarsening are the most important factors affecting the magnetic properties.展开更多
Marine natural gas hydrate has recently attracted global attention as a potential new clean energy source. Laboratory measurements of various physical properties of gas hydrate-bearing marine sediments can provide val...Marine natural gas hydrate has recently attracted global attention as a potential new clean energy source. Laboratory measurements of various physical properties of gas hydrate-bearing marine sediments can provide valuable information for developing efficient and safe extraction technology of natural gas hydrates. This study presents comprehensive measurement results and analysis of drilled hydrate-bearing sediments samples recovered from Qiongdongnan Basin in the South China Sea. The results show that the gas hydrate in the core samples is mainly methane hydrate with a methane content of approximately 95%, and the other components are ethane and carbon dioxide. The saturation of the samples fluctuates from 2%–60%, the porosity is approximately 38%–43%, and the water content is approximately 30%–50%, which indicate that high water saturation means that timely drainage should be paid attention to during hydrate extraction. In addition, the median diameter of the sediment samples is mainly distributed in the range of 15 to 34 µm, and attention should be paid to the prevention and control of sand production in the mining process. Moreover, the thermal conductivity is distributed in the range of 0.75 to 0.96 W/(m·K) as measured by the flat plate heat source method. The relatively low thermal conductivity of hydrates at this study site indicates that a combined approach is encouraged for natural gas production technologies. It is also found that clay flakes and fine particles are attached to the surface of large particles in large numbers. Such characteristics will lead to insufficient permeability during the production process.展开更多
This article analyses and summarizes issues of intellectual property involved in animal-derived regenerative,implantable medical devices(ADRIMD)in order to better understand global trends in patent applications and di...This article analyses and summarizes issues of intellectual property involved in animal-derived regenerative,implantable medical devices(ADRIMD)in order to better understand global trends in patent applications and disclosures,the legal status of patent families(i.e.sets of patents filed in various countries to protect a single invention),and International Patent Classification topics such as main assignee and core expertise.Analysis of research trends will enhance and inform the decision-making capacity of researchers,investors,government regulators and other stake-holders as they undertake to develop,deploy,invest in or regulate ADRIMD.展开更多
Micro-robots have the characteristics of small size,light weight and flexible movement.To design a micro three-legged crawling robot with multiple motion directions,a novel driving scheme based on the inverse piezoele...Micro-robots have the characteristics of small size,light weight and flexible movement.To design a micro three-legged crawling robot with multiple motion directions,a novel driving scheme based on the inverse piezoelectric effect of piezoelectric ceramics was proposed.The three legs of the robot were equipped with piezoelectric bimorphs as drivers,respectively.The motion principles were analyzed and the overall force analysis was carried out with the theoretical mechanics method.The natural frequency,mode shape and amplitude were analyzed with simulation software COMSOL Multiphysics,the optimal size was determined through parametric analysis,and then the micro three-legged crawling robot was manufactured.The effects of different driving voltages,different driving frequencies,different motion bases and different loads on the motion speed of the robot were tested.It is shown that the maximum speed of single-leg driving was 35.41 cm/s,the switching ability between different motion directions was measured,and the movements in six different directions were achieved.It is demonstrated the feasibility of multi-directional motion of the structure.The research may provide a reference for the design and development of miniature piezoelectric three-legged crawling robots.展开更多
The probability, main effect factors and diffusion theory of structural superplastic diffusion bonding of W6Mo5Cr4V2/45 steel have been observed and analyzed by means of tensile test at the room temperature, scanning ...The probability, main effect factors and diffusion theory of structural superplastic diffusion bonding of W6Mo5Cr4V2/45 steel have been observed and analyzed by means of tensile test at the room temperature, scanning electron microscope and microhardness test. Results show that after fine graining treatment and short time superplastic pressing formation under the conditions of superplastic temperature and strain rate, W6Mo5Cr4V2/45 specimens can achieve solid state diffusion bonding and the property of welded area is the same as the other parts in the specimen. The diffusion path of carbon element is intergranular and of dislocation.展开更多
文摘Acrylonitrile-butadiene-Styrene (ABS), with and without calcium carbonate (calcite) particles,was used as the matrix for reinforcement with as-received short-glass fibres (were originallytreated by the manufacturer) and sized short-glass fibres with two amino-silane coupling agents.The calcite particle content is 0, 11.7 and 23.5 vol. pct for the matrices. The glass fiber contentis 0, 10 and 15 vol. pct. The matrix materials and corresponding composites were compoundedusing a twin screw extruder and dumbbell-shaped tensile bars were prepared with an injectionmolding process. The tensile and flexural properties as well as the unnotched and notchedCharpy impact energies of short glass fibre/calcite/ABS composites were studied in this paper.The effects of fibres, fibre surface treatments and particles on these mechanical properties ofthe composites were discussed in detail. An importarit information was obtained, which is thatthe tensile and flexural strengths of hybrid SGF/calcite/ABS composites are the same as thoseof corresponding fibre composites when the ratio of the interfacial adhesion strength betweenparticles and matrix to that between fibres and matrix is higher than certain value. otherwise theformer are lower than the latter.
基金The NSFC-Shandong Joint Fund for Marine Science Research Centers under contract No.U150640007the Natural Science Foundation of Shandong Province of China under contract No.BS2015HZ009the National Natural Science Foundation of China under contract No.41506071
文摘The difference analysis of physical-mechanical properties of muddy sediments is made in the central South Yellow Sea and the Zhe-Min（Zhejiang Province to Fujian Province of China） coastal area. The results show that sediments in the two regions are both dominated by mud. There are perfect negative power function correlations between the water content and the density, the compression coefficient and the compression modulus; a good positive power function correlation between the liquid limit and the plastic limit, a perfect positive linear correlation between the water content and the void ratio, and a perfect polynomial function correlation between the miniature vane shear strength and the pocket penetration resistance. In general, compared with sediments in the Zhe-Min coastal area, sediments in the central South Yellow Sea possess high water content, high void ratio,low density, high plasticity, high compressibility, low shear strength. The causes of the differences between physical-mechanical properties of sediments are analyzed from the topographic features, material sources,hydrodynamic conditions, deposition rate, and material composition. Compared with the Zhe-Min coastal area,the central South Yellow Sea is far from the Mainland and low-lying; has poor hydrodynamic condition; the materials diffused to the area are less and dominated by fine clay, have the high content of smectite and organic matters. These factors lead to sediments of the central South Yellow Sea has the higher water content, the higher plasticity, the lower density, and the lower strength than sediments in the Zhe-Min coastal area.
基金Supported by the Natural Science Foundation of Hunan Province(No.11JJ9006)Key Project of Science and Technology Plan of Hunan Province(2012FJ2002)the Construct Program of the Key Discipline in Hunan Province
文摘A new copper complex 2{Cu（C10H8N2）[C8H11O2（COO）]（H2O）3}·（H2O）5 with bicycle[2.2.1]hept-2-en-5,6-dicarboxylic acid（H2L） [C7H8（COOH）2], basic copper carbonate and 2,2＇-bipyridine has been synthesized in the mixed solvents of methanol and water. It crystallizes in the triclinic system, space group P1, with a = 7.4626（5）, b = 11.9779（8）, c = 12.9841（8）A, α = 109.7040（10）, β = 98.7550（10）, γ = 90.6240（10）°, V = 1077.50（12）A3, Dc = 1.538 g/cm^3, Z = 1, F（000） = 520, GOOF = 1.065, R = 0.0360 and wR = 0.0950. The copper ion is coordinated with four oxygen atoms from one H2 L molecule and three water molecules together with two nitrogen atoms from the 2,2＇-bipyridine molecule, forming a distorted octahedral coordination geometry. The thermal stability and electrochemical properties were also studied.
基金supported by the Foundation of Education Committee of Hunan Province(06C195)the Research Award Fund for Outstanding Young Teachers of Hengyang Normal University(2006)Supported by the construct program of the key discipline in hunan province.
文摘A one-dimensional chain coordination polymer [Cu（phen）（2,4,6-TMBA）2（H2O）]n has been synthesized by reacting 2,4,6-trimethyl-benzoic acid, 1,10-phenanthroline and Cu（Ⅱ） perchlorate and its structure was characterized. Crystal data for this complex： tetragonal, space group I41, a = 2.0293（3）, b = 2.0293（3）, c = 1.3758（2） nm, α =β= γ = 90°, V= 5.6657（13） nm3, Dc= 1.379 g/cm3, Z = 8, μ（MoKa） = 0.815 mm-1, Mr = 588.14, F（000） = 2456, S = 1.047, R = 0.0459 and wR = 0.1053. The crystal structure shows that two neighboring Cu（Ⅱ） ions are linked together by one bridging-chelating 2,4,6-trimethyl-benzoic group, forming a one-dimensional chain structure. Each Cu（Ⅱ） ion is coordinated with two nitrogen atoms from one 1,10-phenanthroline molecule, three oxygen atoms from three 2,4,6-trimethyl-benzoic acid molecules and one oxygen atom from one water molecule, giving a six-coordinate distorted octahedral coordination geometry. The cyclic voltammetry behavior of the complex was also investigated.
基金Supported by the Foundation of Education Committee of Hunan Province (06C195)Fund for Construction of Key Subject in the Eleventh Five-year Plan of Higher Learning of Education in Hunan Province
文摘A novel one-dimensional chain coordination polymer [Mn（NAAh（4,4′-bipy）（H2O）4], has been synthesized with a-naphthaleneacetic acid, 4,4′-bipy and manganese（Ⅱ） sulfate as raw materials. Crystal data for this complex： monoclinic, space group P21/c, a = 1.1421（2）, b = 1.6337（3）, c = 0.94177（19） nm, β = 112.15（3）°, V = 1.6275（6） nm^3, De = 1.407 g/cm^3, Z = 2, μ（MoKa） = 0.467 mm^-1, F（000） = 722, S = 1.007, R= 0.0412 and wR = 0.1022. The crystal structure shows that two neighboring manganese（Ⅱ） ions are linked together by one 4,4′-bipy molecule, and the whole complex molecule forms a one-dimensional chain structure. Each manganese（Ⅱ） ion is coordinated with two oxygen atoms of two a-naphthaleneacetic acid molecules, two nitrogen atoms of two 4,4′-bipy molecules and two oxygen atoms from two water molecules, giving a distorted octahedral coordination geometry. The electrochemical properties were also analyzed.
基金Supported by the construct program of the key discipline in hunan provincethe Research Award Fund for the Outstanding Young Teachers of Hengyang Normal University (2006)
文摘A new cadmium complex [Cd（phen）3]·（ClO4）2·（α-FRA）-（H2O）3 was prepared by self-assembly of α-furoic acid, 1,10-phenanthroline （phen）, and cadmium perchlorate. It crystallizes in the monoclinic system, space group P21/n, with a = 1.28130（15）, b = 2.5957（3）, c = 1.35449（16） nm, β = 109.395（2）°, V = 4.2492（9） nm^3, Dc = 1.491 g/cm^3, Z = 4, F（000） = 1926, GOOF = 1.023, the final R = 0.0729 and wR = 0.2086. The crystal structure analysis indicates that the cadmium ion is coordinated with six nitrogen atoms from six 1,10-phenanthroline molecules, giving a distorted octahedral coordination geometry. The cyclic voltametric behavior of the complex was also investigated.
基金the Foundation of Education Committee of Hunan Province (06C195)the Research Award Fund for Outstanding Young Teachers of Hengyang Normal University (2006)the construct program of the Key Discipline in Hunan Province
文摘One new cadmium complex [Cd（phen）3]·（ClO4）2·（p-MBA）2·（H2O）2 has been hydrothermally synthesized by reacting p-methylbenzoic acid （p-MBA）, 1,10-phenanthroline （phen） and cadmium perchlorate. It crystallizes in the triclinic system, space group P1, with a = 1.2809（3）, b = 1.3431（3）, c = 1.3734（3） nm, α = 84.259（4）, β = 71.603（3）, γ = 74.424（3）°, V= 2.1594（8） nm3, Do = 1.532 g/cm3, Z = 2, F（000） = 1008, μ= 0.697 mm^-1, R = 0.0646 and wR = 0.1648. The crystal structure shows that the cadmium ion is coordinated with six nitrogen atoms from three 1,10-phenanthroline molecules, forming a distorted octahedral coordination geometry. The result of electrochemical property analysis shows that the electron transfer in the electrode reaction is irreversible.
文摘For the handling, treatment and utilization of fly ash from biomass combustion its chemical composition and physical properties are important. In this study eight filter fly ashes from different grate-fired biomass combustion plants were investigated. In fly ash from straw combustion high concentrations of（K） were found, whereas in the fly ash from wood combustion the concentrations of Ca and Mg were higher. The average concentration of PO3-4was similar in both types of fly ashes. In all wood fly ashes some measured heavy metal concentrations were above the limits for utilization. The straw fly ashes were much less contaminated and can be utilized. For wood fly ash most parameters showed little variation, except from one fly ash where the dust pre-separator is in poor condition. The average values were： mass median diameter 4.3 ± 0.8 μm, spread of particle size distribution19 ± 11, particle density 2620 ± 80 kg/m^3 and angle of repose 50°± 1°. The density of the straw fly ashes is lower（2260 ± 80 kg/m^3） and the spread of the size distribution is higher（72 ± 24）.For one straw combustion fly ash the values of the mass median diameter and the angle of repose were similar to the values of wood combustion fly ash, for the other straw fly ash the values differed considerably. While the particle size of this fly ash was much smaller,surprisingly the angle of repose was also lower. This can be attributed to the formation of small agglomerates in this fly ash, which were not disintegrated without a certain stress.
基金supported by the National Natural Science Foundation of China(6100121161303035+1 种基金61471283)the Fundamental Research Funds for the Central Universities(K5051202016)
文摘Bistatic forward-looking synthetic aperture radar（SAR） has many advantages and applications owing to its twodimensional imaging capability.There could be various imaging configurations because of the geometric flexibility of bistatic platforms,resulting in kinds of models built independently among which there could be some similar even the same motion features.Comprehensive research on such systems in a more comprehensive and general point of view is required to address their difference and consistency.Property analysis of bistatic forwardlooking SAR with arbitrary geometry is achieved including stripmap and spotlight modes on airborne platform,missile-borne platform,and hybrid platform of both.Emphasis is placed on azimuth space variance of some key parameters significantly affecting the subsequent imaging processing,based on which the frequency spectra are further described and compared considering respective features of different platforms for frequency imaging algorithm developing.Simulation results confirm the effectiveness and correctness of our analysis.
文摘In open-pit mines,pit slope as one of the important parameters affects the mine economy and total minable reserve,and it is also affected by different uncertainties which arising from many sources.One of the most critical sources of uncertainty effects on the pit slope design is rock mass geomechanical properties.By comparing the probability of failure resulted from deterministic procedure and probabilistic one,this paper investigated the effects of aforesaid uncertainties on open-pit slope stability in metal mines.In this way,to reduce the effect of variance,it implemented Latin Hypercube Sampling(LHS)technique.Furthermore,a hypothesis test was exerted to compare the effects on two cases in Middle East.Subsequently,the investigation approved high influence of geomechanical uncertainties on overall pit steepness and stability in both iron and copper mines,though on the first case the effects were just over.
基金National Natural Science Foundation of China(51208296&51478343)Shanghai Committee of Science and Technology(13231200503)+2 种基金Fundamental Research Funds for the Central Universities(2013KJ095&101201438)Shanghai Educational Development Foundation(13CG17)National Key Technology R&D Program(2012BAK24B04)
文摘Discrete models such as the lumped parameter model and the finite element model are widely used in the solution of soil amplification of earthquakes. However, neither of the models will accurately estimate the natural frequencies of soil deposit, nor simulate a damping of frequency independence. This research develops a new discrete model for onedimensional viscoelastic response analysis of layered soil deposit based on the mode equivalence method. The new discrete model is a one-dimensional equivalent multi-degree-of-freedom（MDOF） system characterized by a series of concentrated masses, springs and dashpots with a special configuration. The dynamic response of the equivalent MDOF system is analytically derived and the physical parameters are formulated in terms of modal properties. The equivalent MDOF system is verified through a comparison of amplification functions with the available theoretical solutions. The appropriate number of degrees of freedom（DOFs） in the equivalent MDOF system is estimated. A comparative study of the equivalent MDOF system with the existing discrete models is performed. It is shown that the proposed equivalent MDOF system can exactly present the natural frequencies and the hysteretic damping of soil deposits and provide more accurate results with fewer DOFs.
基金Funded by the National Natural Science Foundation of China(No.50902107)the Fundamental Research Funds for the Central Universities(No.2013-YB-25)
文摘Recycled ceramic mixed sand（RCMS） was obtained by partially replacing ultra-fine sand with recycled ceramic coarse sand（RCCS）. The effects of RCCS replacement rate on the apparent density, workability, compressive strength and splitting tensile strength of recycled ceramic concrete（RCC） were investigated. In addition, the relationship between the water-cement ratio and compressive strength of RCC was also studied. The experimental results indicate that the reusing of recycled ceramic aggregate can improve the cohesiveness and water retentiveness of fresh concrete and benefit the mechanical properties development. When the RCCS replacement rate is not less than 40%, the mechanical properties of RCC are superior to those of the reference concrete. Moreover, when recycled ceramic medium sand was completely used as fine aggregate, the maximum increase in both compressive strength and splitting tensile strength were obtained, comparing with those of reference concrete, the increment ratio was 19.85% and 32.73%, respectively. The microscopic analysis shows that the using of recycled ceramic aggregate can meliorate distinctly the structure of the interfacial transition zone（ITZ） and increase the compaction degree of cement paste. Furthermore, an expression of the compressive strength of RCC and the cement-water ratio is regressed and gains a good linear relativity. It is an effective way to recycle waste ceramic, and the consumption of recycled ceramic aggregate could reach from 26.9% to 47.6% of the total weight of aggregate in producing concrete.
基金supported by the National Key Basic Research Program of China(973 Program)2015CB251002National Natural Science Foundation of China under Grant 51521065,51577145+1 种基金the Fundamental Research Funds for the Central UniversitiesShaanxi Province Natural Science Foundation 2013JM-7010
文摘Influence of the gassing materials, such as PA6, PMMA, and POM on the dielectric properties of air are investigated. In this work, the fundamental electron collision cross section data were carefully selected and validated. Then the species compositions of the air–organic vapor mixtures were calculated based on the Gibbs free energy minimization. Finally, the Townsend ionization coefficient, the Townsend electron attachment coefficient and the critical reduced electric field strength were derived from the calculated electron energy distribution function by solving the Boltzmann transport equation. The calculation results indicated that H;O with large attachment cross sections has a great impact on the critical reduced electric field strength of the air–organic vapor mixtures. On the other hand, the vaporization of gassing materials can help to increase the dielectric properties of air circuit breakers to some degree.
基金Project supported by Russian Foundation for Basic Research(12-03-00042)
文摘Nd Sr2Mn2O7＋δ compounds were synthesized by ceramic method under three different cooling conditions. The Nd Sr2Mn2O7＋δ samples were characterized by powder X-ray diffraction（XRD）. Oxygen non-stoichiometry data for the studied powders were determined by using gravimetric and X-ray photoelectron spectroscopy（XPS） methods. The correlation of cooling method and oxygen as non-stoichiometry was established. The electroconductivity in samples was studied by using four-point probe method, and the strong correlation with non-stoichiometry was found out. Magnetization measurements were carried out. It was found that the magnetic and transport properties of the samples were also influenced by oxygen non-stoichiometry. The evolution of the magnetic properties could be explained by the formation of magnetic clusters in the vicinity of oxygen vacancies（OV） and strong competition between the superexchange and double exchange interactions.
文摘This research aims to investigate the effect of pulsed Nd：YAG laser micro-welding on the microstructure,texture and magnetic properties of ultra-thin Fe-Co-7.15 wt%V magnetic alloy.Optical microscopy,scanning electron microscopy and electron backscattered diffraction techniques were used to study the microstructural evolutions.Also,vibrating sample magnetometry was used to characterize the magnetic properties.The results showed that the fractions of low Σ coincidence site lattice boundaries in the fusion zone are higher than those of the base metal.The welded samples experience a significant decrease in their magnetic properties.It was found that the formation of new fiber texture in the fusion zone and grain coarsening are the most important factors affecting the magnetic properties.
基金This work was supported by the National Natural Science Foundation of China (Grant No. U19B2005).
文摘Marine natural gas hydrate has recently attracted global attention as a potential new clean energy source. Laboratory measurements of various physical properties of gas hydrate-bearing marine sediments can provide valuable information for developing efficient and safe extraction technology of natural gas hydrates. This study presents comprehensive measurement results and analysis of drilled hydrate-bearing sediments samples recovered from Qiongdongnan Basin in the South China Sea. The results show that the gas hydrate in the core samples is mainly methane hydrate with a methane content of approximately 95%, and the other components are ethane and carbon dioxide. The saturation of the samples fluctuates from 2%–60%, the porosity is approximately 38%–43%, and the water content is approximately 30%–50%, which indicate that high water saturation means that timely drainage should be paid attention to during hydrate extraction. In addition, the median diameter of the sediment samples is mainly distributed in the range of 15 to 34 µm, and attention should be paid to the prevention and control of sand production in the mining process. Moreover, the thermal conductivity is distributed in the range of 0.75 to 0.96 W/(m·K) as measured by the flat plate heat source method. The relatively low thermal conductivity of hydrates at this study site indicates that a combined approach is encouraged for natural gas production technologies. It is also found that clay flakes and fine particles are attached to the surface of large particles in large numbers. Such characteristics will lead to insufficient permeability during the production process.
基金supported by the National Engineering Laboratory for Regenerative Medical Implantable Devices(Grant No.2012NEL2MD005).
文摘This article analyses and summarizes issues of intellectual property involved in animal-derived regenerative,implantable medical devices(ADRIMD)in order to better understand global trends in patent applications and disclosures,the legal status of patent families(i.e.sets of patents filed in various countries to protect a single invention),and International Patent Classification topics such as main assignee and core expertise.Analysis of research trends will enhance and inform the decision-making capacity of researchers,investors,government regulators and other stake-holders as they undertake to develop,deploy,invest in or regulate ADRIMD.
基金supported by the National Natural Science Foundation of China (grant no.51505133)by Key Research Project in Colleges and Universities of Henan Province (23A460010)by Opening Project of Henan Engineering Laboratory of Photoelectric Sensor and Intelligent Measurement and Control,Henan Polytechnic University (grant no.HELPSIMC-2020-006).
文摘Micro-robots have the characteristics of small size,light weight and flexible movement.To design a micro three-legged crawling robot with multiple motion directions,a novel driving scheme based on the inverse piezoelectric effect of piezoelectric ceramics was proposed.The three legs of the robot were equipped with piezoelectric bimorphs as drivers,respectively.The motion principles were analyzed and the overall force analysis was carried out with the theoretical mechanics method.The natural frequency,mode shape and amplitude were analyzed with simulation software COMSOL Multiphysics,the optimal size was determined through parametric analysis,and then the micro three-legged crawling robot was manufactured.The effects of different driving voltages,different driving frequencies,different motion bases and different loads on the motion speed of the robot were tested.It is shown that the maximum speed of single-leg driving was 35.41 cm/s,the switching ability between different motion directions was measured,and the movements in six different directions were achieved.It is demonstrated the feasibility of multi-directional motion of the structure.The research may provide a reference for the design and development of miniature piezoelectric three-legged crawling robots.
文摘The probability, main effect factors and diffusion theory of structural superplastic diffusion bonding of W6Mo5Cr4V2/45 steel have been observed and analyzed by means of tensile test at the room temperature, scanning electron microscope and microhardness test. Results show that after fine graining treatment and short time superplastic pressing formation under the conditions of superplastic temperature and strain rate, W6Mo5Cr4V2/45 specimens can achieve solid state diffusion bonding and the property of welded area is the same as the other parts in the specimen. The diffusion path of carbon element is intergranular and of dislocation.
