Virtual property has increasingly become a key issue,particularly regarding its nature,ownership,and goodwill acquisition,all of which are worthy of study.Analyzing these issues can contribute to a better understandin...Virtual property has increasingly become a key issue,particularly regarding its nature,ownership,and goodwill acquisition,all of which are worthy of study.Analyzing these issues can contribute to a better understanding of how to develop laws and regulations to protect virtual property.展开更多
Goji berry(Lycium barbarum L.)is substantially dependent on nitrogen fertilizer application,which can signifi-cantly enhance fruit yield and Goji berry industrial development in Ningxia,China.This study aimed to analyz...Goji berry(Lycium barbarum L.)is substantially dependent on nitrogen fertilizer application,which can signifi-cantly enhance fruit yield and Goji berry industrial development in Ningxia,China.This study aimed to analyze the functions of differential nitrogen application rates including low(N1),medium(N2),and high(N3)levels in soil microbial community structure(bacterial and fungal)at 2 diverse soil depths(0-20,20-40 cm)through high-throughput sequencing technology by targeting 16S RNA gene and ITS1&ITS2 regions.All the observed physicochemical parameters exhibited significant improvement(p<0.05)with increased levels of nitrogen and the highest values for most parameters were observed at N2.However,pH decreased(p<0.05)gradually.The alpha and beta diversity analyses for bacterial and fungal communities’metagenome displayed more similarities than differences among all groups.The top bacterial and fungal phyla and genera suggested no obvious(p>0.05)differences among three group treatments(N1,N2,and N3).Furthermore,the functional enrichment analysis demonstrated significant(p<0.05)enrichment of quorum sensing,cysteine and methionine metabolism,and transcriptional machinery for bacterial communities,while various saprotrophic functional roles for fungal communities.Conclusively,moderately reducing the use of N-supplemented fertilizers is conducive to increasing soil nitrogen utilization rate,which can contribute to sustainable agriculture practices through improved soil quality,and microbial community structure and functions.展开更多
Editor's note: On July 10,2005, a draft of Real Rights Law of the People's Republic of China was made public for opinions and suggestions from peo- ple of all walks of life. Following is a transcript of an int...Editor's note: On July 10,2005, a draft of Real Rights Law of the People's Republic of China was made public for opinions and suggestions from peo- ple of all walks of life. Following is a transcript of an interview by our reporter with Professor Wang Liming of the Renmin University of China, a noted expert of law, who is involved in the drafting of the law:展开更多
The structural parameters, chemical bonding and elastic properties of the tetragonal phase quaternary arsenide oxides YZnAsO and LaZnAsO were investigated by using density-functional theory (DFT) within generalized ...The structural parameters, chemical bonding and elastic properties of the tetragonal phase quaternary arsenide oxides YZnAsO and LaZnAsO were investigated by using density-functional theory (DFT) within generalized gradient approximation (GGA). The GGA calculated structural parameters are in agreement with the experimental results. Population analysis suggests that the chemical bonding in YZnAsO and LaZnAsO can be classified as a mixture of ionic and covalent characteristic. Single-crystal elastic constants were calculated and the polycrystalline elastic modules were estimated according to Voigt, Reuss and Hill's approximations (VRH). The result shows that both YZnAsO and LaZnAsO are relatively soft materials exhibiting ductile behavior. The calculated polycrystalline elastic anisotropy result shows that LaZnAsO is more anisotropy in compressibility and YZnAsO is more anisotropy in shear.展开更多
Bioleaching and electrochemical experiments were conducted to evaluate marmatite dissolution in the presence of pure S.thermosulfidooxidans.The effects of particle size,p H controlling and external addition of Fe^3+ ...Bioleaching and electrochemical experiments were conducted to evaluate marmatite dissolution in the presence of pure S.thermosulfidooxidans.The effects of particle size,p H controlling and external addition of Fe^3+ ions on the zinc extraction were investigated.The results show that in the bioleaching process the best particle size range is 0.043-0.074 mm and adjusting p H regularly to the initial value has a profound effect on obtaining high leaching rate.External addition of Fe^3+ ions could accelerate the bioleaching,while the concentration of additional Fe^3+ over 2.5 g/L weakens the positive effect,and even hinders the dissolution of marmatite.SEM and XRD analyses of the leaching residues reveal that a product layer composed of elemental sulfur and jarosite is formed on the mineral surface,which results in a low leaching speed at later phase.The results of electrochemical measurements illustrate that additional Fe^3+ ions could increase the corrosion current density,which is favorable to zinc extraction.The EIS spectra show that rate-limiting step does not change when Fe^3+ ions are added.展开更多
The Cu2S/tetrapod-like ZnO whisker(T-ZnOw) heterostructures were successfully synthesized via a simple polyol process employing the poly(vinyl pyrrolidone)(PVP) as a surfactant.The as-prepared heterostructures w...The Cu2S/tetrapod-like ZnO whisker(T-ZnOw) heterostructures were successfully synthesized via a simple polyol process employing the poly(vinyl pyrrolidone)(PVP) as a surfactant.The as-prepared heterostructures were characterized by X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),X-ray photoelectron spectroscopy(XPS) and Fourier transform infrared(FTIR).The photocatalytic properties of Cu2S/T-ZnOw nanocomposites synthesized with different PVP concentrations were evaluated by photodegradation of methyl orange(MO) under UV irradiation.The results show that the Cu2S/T-ZnOw nanocomposites exhibit remarkable improved photocatalytic property compared with the pure T-ZnOw.The sample prepared with 3.0 g/L PVP shows an excellent photocatalytic property and the highest photodegradation rate of MO is 97% after UV irradiation for 120 min.Besides,the photocatalytic activity of the photocatalyst has no evident decrease even after four cycles,which demonstrates that the Cu2S/T-ZnOw photocatalyst exhibits an excellent photostability.Moreover,the photocatalytic mechanism of the Cu2S/T-ZnOw nanocomposites was also discussed.展开更多
The effects of Zn content on the microstxucture and the mechanical and corrosion properties of as-cast low-alloyed Mg-xZn~.2Ca alloys (x = 0.6wt%, 2.0wt%, 2.5wt%, hereafter denoted as 0.6Zn, 2.0Zn, and 2.5Zn alloys, ...The effects of Zn content on the microstxucture and the mechanical and corrosion properties of as-cast low-alloyed Mg-xZn~.2Ca alloys (x = 0.6wt%, 2.0wt%, 2.5wt%, hereafter denoted as 0.6Zn, 2.0Zn, and 2.5Zn alloys, respectively) axe investigated. The results show that the Zn content not only influences grain refinement but also induces different phase precipitation behaviors. The as-cast microstxucture of the 0.6Zn alloy is composed of ct-Mg, Mg2Ca, and Ca2Mg6Zn3 phases, whereas 2.0Zn and 2.5Zn alloys only contain ct-Mg and Ca2Mg6Zn3 phases, as revealed by X-ray diffraction (XRD) and txonsmission electron microscopy (TEM) analyses. Moreover, with in- creasing Zn content, both the ultimate tensile strength (UTS) and the elongation to fracture first increase and then decrease. Among the three investigated alloys, the largest UTS (178 MPa) and the highest elongation to fracture (6.5%) are obtained for the 2.0Zn alloy. In addition, the corrosion rate increases with increasing Zn content. This paper provides on updated investigation of the alloy composi- tion-microstxucture-property relationships of different Zn-containing Mg-Zn-Ca alloys.展开更多
The interactions of Sn and S and their effects on the magnetic properties of non-oriented silicon steel sheets were discussed in reference to industrial production. Results show that minor amounts of Sn can improve ma...The interactions of Sn and S and their effects on the magnetic properties of non-oriented silicon steel sheets were discussed in reference to industrial production. Results show that minor amounts of Sn can improve magnetic induction sharply but have little effect on core loss when the S content is below 10 × 10 ^-4%. The precipitation of AlN can be restrained effectively by Sn. Sn, as the nucleus, can remove some of the inclusions with a size of 0.5μm or larger, but has little effect on inclusions smaller than 0.5 μm,which is the key factor affecting core loss. Sn improves the magnetic induction of finished steel sheets mainly through the change of the steel texture. The relationship between the magnetic induction and Sn and S content can be regressed as B50 = 1.69 -4.37 ws +0.30 Ws,. From the regression formulation,the magnetic induction can be improved by 0.03 T when 0.01% Sn is added under relatively low S content conditions.展开更多
The ecological effect of reclaimed water irrigation and fertilizer application on the soil environment is receiving more attention.Soil microbial activity and nitrogen(N)levels are important indicators of the effect...The ecological effect of reclaimed water irrigation and fertilizer application on the soil environment is receiving more attention.Soil microbial activity and nitrogen(N)levels are important indicators of the effect of reclaimed water irrigation on environment.This study evaluated soil physicochemical properties and microbial community structure in soils irrigated with reclaimed water and receiving varied amounts of N fertilizer.The results indicated that the reclaimed water irrigation increased soil electrical conductivity(EC)and soil water content(SWC).The N treatment has highly significant effect on the ACE,Chao,Shannon(H)and Coverage indices.Based on a 16S ribosomal RNA(16S rRNA)sequence analysis,the Proteobacteria,Gemmatimonadetes and Bacteroidetes were more abundant in soil irrigated with reclaimed water than in soil irrigated with clean water.Stronger clustering of microbial communities using either clean or reclaimed water for irrigation indicated that the type of irrigation water may have a greater influence on the structure of soil microbial community than N fertilizer treatment.Based on a canonical correspondence analysis(CCA)between the species of soil microbes and the chemical properties of the soil,which indicated that nitrate N(NO3-–-N)and total phosphorus(TP)had significant impact on abundance of Verrucomicrobia and Gemmatimonadetes,meanwhile the p H and organic matter(OM)had impact on abundance of Firmicutes and Actinobacteria significantly.It was beneficial to the improvement of soil bacterial activity and fertility under 120 mg kg^-1 N with reclaimed water irrigation.展开更多
The self-healing microcapsules can be buried in the coating to improve the anticorrosive ability.In this paper,self-healing microcapsules of polyurea(PU)/melamine resin(MF)double shell were prepared by in-situ polymer...The self-healing microcapsules can be buried in the coating to improve the anticorrosive ability.In this paper,self-healing microcapsules of polyurea(PU)/melamine resin(MF)double shell were prepared by in-situ polymerization and interfacial polymerization with isocyanate as the core material.Scanning electron microscope was used to observe the microcapsule morphology.The structures of microcapsules prepared with different chain extenders were characterized by Fourier transform infrared spectroscopy.The micromanipulation system was used to loading–holding,loading–unloading and loading to rupture individual microcapsules,so as to explore the mechanical properties of microcapsules.The Young’s modulus corresponding to microcapsules was calculated by mathematical model fitting.The self-healing properties of microcapsule coating were characterized by optical microscope.The experimental results showed that the microcapsule shell prepared under optimized conditions had a complete morphology and good mechanical properties.The microcapsule was in the elastic deformation stage under small deformation,and the plastic deformation stage under large deformation.The Young’s modulus range of microcapsules was 9.29–14.51 MPa,and the corresponding Young’s modulus could be prepared by adjusting the process.The surface crack of the coating containing microcapsule could heal itself after48 h in a humid environment.展开更多
A yeast strain R6 was obtained by the method of thiamine(VB1) auxotrophic negative selection from the edible oil-polluted soil in Zibo, China. Physiological and biochemical experiments revealed that strain R6 shared...A yeast strain R6 was obtained by the method of thiamine(VB1) auxotrophic negative selection from the edible oil-polluted soil in Zibo, China. Physiological and biochemical experiments revealed that strain R6 shared common feature with Rhodotorula mucilaginosa according to the API 20 C AUX yeast identification system which has been tested previously. Furthermore, the 18 S r DNA gene of strain R6 was amplified and sequenced. Phylogenetic analysis based on the 18 S r DNA sequence and the relatives indicated that R6 shared 99% homologies with the members of R. mucilaginosa, suggesting that strain R6 belonged to R. mucilaginosa.Investigation showed that strain R6 possessed the capacity of accumulating exocellular alpha-ketoglutaric acid(alpha-KG). Finally, the fermentation conditions of R6 to accumulate alpha-KG was optimized by controlling each single fermenting variable and detected through high performance liquid chromatography(HPLC). Results showed that both VB1 and Ca CO3 in fermentation medium were the key factors influencing the cumulant of alpha-KG. The discovery of natural auxotrophic strain R6 not only broadened the microbial resource which can achieve lots of alpha-KG production through fermentation, but also laid a foundation for further fermentation regulation to achieve excessive alpha-KG accumulation.展开更多
Calcined ginger nuts admixed by fly ash and quartz sand (CGN-(F+S)) has been validated to be basically compatible to earthen sites as an anchor grout. Accelerated ageing tests including water stability test, temperatu...Calcined ginger nuts admixed by fly ash and quartz sand (CGN-(F+S)) has been validated to be basically compatible to earthen sites as an anchor grout. Accelerated ageing tests including water stability test, temperature and humidity cycling test, soundness test and alkali resistance test are conducted with the objective to further research the property changes of CGN-(F+S) grout. Density, surface hardness, water penetration capacity, water permeability capacity, soluble salt, scanning electron microscopy (SEM) images and energy dispersive spectrometry (EDS) spectrum of these samples have been tested after accelerated ageing tests. The results show that densities of samples decrease, surface hardness, water penetration capacity and water permeability capacity of samples increase generally. Besides, soluble salt analysis, SEM and EDS results well corroborate the changes. Based on the results it can be concluded that property changes are most serious after temperature and humidity cycling test, followed by water stability, soundness and alkali resistance test in sequence. But in general, CGN-(F+S) still has good durability.展开更多
By using the steady-state seepage method, a patent seepage device together with the MTS815.02 Rock Mechanics Test System is used to test the seepage properties of non-Darcy flow in a granular gangue with five differen...By using the steady-state seepage method, a patent seepage device together with the MTS815.02 Rock Mechanics Test System is used to test the seepage properties of non-Darcy flow in a granular gangue with five different grain sizes during the compaction. The experimental results show that the seepage properties are not only related to the stress or displacement level, but also to the grain size, the pore structure of the granular gangue, and the current porosity The permeability and the non-Darcy flow coefficient can be fitted respectively by the cubic polynomials and the power functions of the porosity, Formally, the flow in granular gangue satisfies the Forchheimer's binomial flow, but under the great axial and confining pressure and owing to the grain's crushing, the flow in granular gangues is different from that in rock-fills which are naturallv oiled un. As a result, the non-Darer flow coefficient may be negative.展开更多
An excellent organic blue light-emitting diode based on 4,4'-bis(diphenylamino)-quinque(p-phenylene)s (OPP(5)-NPh) with a maximum luminance of up to 5000 cd/m^2 and a luminanous efficiency of 1.3 cd/A was rep...An excellent organic blue light-emitting diode based on 4,4'-bis(diphenylamino)-quinque(p-phenylene)s (OPP(5)-NPh) with a maximum luminance of up to 5000 cd/m^2 and a luminanous efficiency of 1.3 cd/A was reported. This diode was made by using a wide band-gap hole-blocking layer, F-TBB instead of PBD in the OLED devices. We attribute the good performance to the one trade-off involved in the use of F-TBB to obtain higher luminance is the increased turn-on voltages and slightly decreased device efficiencies.展开更多
Utilized degradable data of coal-filled films from the accelerated UV chamber ageing degradation experiments, and on the basis of control factors’ analysis, presented a predicting model on degradable properties of th...Utilized degradable data of coal-filled films from the accelerated UV chamber ageing degradation experiments, and on the basis of control factors’ analysis, presented a predicting model on degradable properties of this film in photo-degradation according to back-propagation artificial neural network (BP ANN). 4 controlling factors in films degrada-tion, including temperature, the time of UV irradiation, the concentration and the type of coals were used as input parameters in the ANN model. While the degradable properties after film degradation, including the mechanical properties and carbonyl index, were used as output parameters. It was carried out by the neural network toolbox of Matlab 6.5 soft-ware and Visual Basic 6.0. Discussed partition of sample data and model’s parameters, and then selected the best configuration of ANN network. The accurate scope of predicting results was analyzed. This model has a high precision in predicting on properties of the coal-filled film degradation.展开更多
Structural, electronic, and optical properties of alloys BexMgl-xX (X = S, Se, Te) in the assortment 0 〈 x 〈 1 were theoretically reported for the first time in zinc-blende (ZB) phase. The calculations were carr...Structural, electronic, and optical properties of alloys BexMgl-xX (X = S, Se, Te) in the assortment 0 〈 x 〈 1 were theoretically reported for the first time in zinc-blende (ZB) phase. The calculations were carried out by using full-potential linearized augmented plane wave plus local orbitals (FP-LAPW+lo) formalism contained by the framework of density functional theory (DFT). Wu--Cohen (WC) generalized gradient approximation (GGA), based on optimization energy, has been applied to calculate these theoretical results. In addition, we used Becke and Johnson (mBJ-GGA) potential, modified form of GGA functional, to calculate electronic structural properties up to a high precision degree. The alloys were composed with the concentrations x = 0.25, 0.5, and 0.75 in pursuance of 'special quasi-random structures' (SQS) approach of Zunger for the restoration of disorder around the observed site of alloys in the first few shells. The structural parameters have been predicted by minimizing the total energy in correspondence of unit cell volume. Our alloys established direct band gap at different concentrations that make their importance in optically active materials. Furthermore, density of states was discussed in terms of the contribution of Be and Mg s and chalcogen (S, Se, and Te) s and p states and observed charge density helped us to investigate the bonding nature. By taking into consideration of immense importance in optoelectronics of these materials, the complex dielectric function was calculated for incident photon energy in the range 0--15 eV.展开更多
The transport properties of hexagonal boron-nitride nanoribbons under the uniaxial strain are investigated by the Green's function method. We find that the transport properties of armchair boron-nitride nanoribbon st...The transport properties of hexagonal boron-nitride nanoribbons under the uniaxial strain are investigated by the Green's function method. We find that the transport properties of armchair boron-nitride nanoribbon strongly depend on the strain. In particular, the features of the conductance steps such as position and width are significantly changed by strain. As a strong tensile strain is exerted on the nanoribbon, the highest conductance step disappears and subsequently a dip emerges instead. The energy band structure and the local current density of armchair boron nitride nanoribbon under strain are calculated and analysed in detail to explain these characteristics. In addition, the effect of strain on the conductance of zigzag boron-nitride nanoribbon is weaker than that of armchair boron nitride nanoribbon.展开更多
In this paper, let T be a bounded linear operator on a complex Hilbert H. We give and prove that every p-w-hyponormal operator has Bishop's property(β) and spectral properties; Quasi-similar p-w-hyponormal operat...In this paper, let T be a bounded linear operator on a complex Hilbert H. We give and prove that every p-w-hyponormal operator has Bishop's property(β) and spectral properties; Quasi-similar p-w-hyponormal operators have equal spectra and equal essential spectra. Finally, for p-w-hyponormal operators, we give a kind of proof of its normality by use of properties of partial isometry.展开更多
文摘Virtual property has increasingly become a key issue,particularly regarding its nature,ownership,and goodwill acquisition,all of which are worthy of study.Analyzing these issues can contribute to a better understanding of how to develop laws and regulations to protect virtual property.
基金This work was funded by Ningxia Hui Autonomous Region Key Research and Development Project(2021BEF02004),Central Finance Forestry Reform and Development Fund“Forest Seed Cultivation”.
文摘Goji berry(Lycium barbarum L.)is substantially dependent on nitrogen fertilizer application,which can signifi-cantly enhance fruit yield and Goji berry industrial development in Ningxia,China.This study aimed to analyze the functions of differential nitrogen application rates including low(N1),medium(N2),and high(N3)levels in soil microbial community structure(bacterial and fungal)at 2 diverse soil depths(0-20,20-40 cm)through high-throughput sequencing technology by targeting 16S RNA gene and ITS1&ITS2 regions.All the observed physicochemical parameters exhibited significant improvement(p<0.05)with increased levels of nitrogen and the highest values for most parameters were observed at N2.However,pH decreased(p<0.05)gradually.The alpha and beta diversity analyses for bacterial and fungal communities’metagenome displayed more similarities than differences among all groups.The top bacterial and fungal phyla and genera suggested no obvious(p>0.05)differences among three group treatments(N1,N2,and N3).Furthermore,the functional enrichment analysis demonstrated significant(p<0.05)enrichment of quorum sensing,cysteine and methionine metabolism,and transcriptional machinery for bacterial communities,while various saprotrophic functional roles for fungal communities.Conclusively,moderately reducing the use of N-supplemented fertilizers is conducive to increasing soil nitrogen utilization rate,which can contribute to sustainable agriculture practices through improved soil quality,and microbial community structure and functions.
文摘Editor's note: On July 10,2005, a draft of Real Rights Law of the People's Republic of China was made public for opinions and suggestions from peo- ple of all walks of life. Following is a transcript of an interview by our reporter with Professor Wang Liming of the Renmin University of China, a noted expert of law, who is involved in the drafting of the law:
基金Project(50474051)supported by the National Natural Science Foundation of China
文摘The structural parameters, chemical bonding and elastic properties of the tetragonal phase quaternary arsenide oxides YZnAsO and LaZnAsO were investigated by using density-functional theory (DFT) within generalized gradient approximation (GGA). The GGA calculated structural parameters are in agreement with the experimental results. Population analysis suggests that the chemical bonding in YZnAsO and LaZnAsO can be classified as a mixture of ionic and covalent characteristic. Single-crystal elastic constants were calculated and the polycrystalline elastic modules were estimated according to Voigt, Reuss and Hill's approximations (VRH). The result shows that both YZnAsO and LaZnAsO are relatively soft materials exhibiting ductile behavior. The calculated polycrystalline elastic anisotropy result shows that LaZnAsO is more anisotropy in compressibility and YZnAsO is more anisotropy in shear.
基金Project(2010CB630903)supported by the National Basic Research Program of ChinaProject(51374249)supported by the National Natural Science Foundation of China
文摘Bioleaching and electrochemical experiments were conducted to evaluate marmatite dissolution in the presence of pure S.thermosulfidooxidans.The effects of particle size,p H controlling and external addition of Fe^3+ ions on the zinc extraction were investigated.The results show that in the bioleaching process the best particle size range is 0.043-0.074 mm and adjusting p H regularly to the initial value has a profound effect on obtaining high leaching rate.External addition of Fe^3+ ions could accelerate the bioleaching,while the concentration of additional Fe^3+ over 2.5 g/L weakens the positive effect,and even hinders the dissolution of marmatite.SEM and XRD analyses of the leaching residues reveal that a product layer composed of elemental sulfur and jarosite is formed on the mineral surface,which results in a low leaching speed at later phase.The results of electrochemical measurements illustrate that additional Fe^3+ ions could increase the corrosion current density,which is favorable to zinc extraction.The EIS spectra show that rate-limiting step does not change when Fe^3+ ions are added.
基金Project (2009AA03Z427) supported by the High-tech Research and Development Program of ChinaProject (2006z02-006-3) supported by the Science Foundation of Sichuan Province,China
文摘The Cu2S/tetrapod-like ZnO whisker(T-ZnOw) heterostructures were successfully synthesized via a simple polyol process employing the poly(vinyl pyrrolidone)(PVP) as a surfactant.The as-prepared heterostructures were characterized by X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),X-ray photoelectron spectroscopy(XPS) and Fourier transform infrared(FTIR).The photocatalytic properties of Cu2S/T-ZnOw nanocomposites synthesized with different PVP concentrations were evaluated by photodegradation of methyl orange(MO) under UV irradiation.The results show that the Cu2S/T-ZnOw nanocomposites exhibit remarkable improved photocatalytic property compared with the pure T-ZnOw.The sample prepared with 3.0 g/L PVP shows an excellent photocatalytic property and the highest photodegradation rate of MO is 97% after UV irradiation for 120 min.Besides,the photocatalytic activity of the photocatalyst has no evident decrease even after four cycles,which demonstrates that the Cu2S/T-ZnOw photocatalyst exhibits an excellent photostability.Moreover,the photocatalytic mechanism of the Cu2S/T-ZnOw nanocomposites was also discussed.
基金supported by the National Natural Science Foundation of China(No.51671017)Fundamental Research Funds for the Central Universities(No.FRF-GF-17-B3)+1 种基金Beijing Laboratory of Metallic Materials and Processing for Modern Transportation,the Opening Research Fund of State Key Laboratory for Advanced Metals and Materials(Nos.2016Z-11,2017Z-08)State's Key Project of Research and Development Plan(No.2016YFB0300801)
文摘The effects of Zn content on the microstxucture and the mechanical and corrosion properties of as-cast low-alloyed Mg-xZn~.2Ca alloys (x = 0.6wt%, 2.0wt%, 2.5wt%, hereafter denoted as 0.6Zn, 2.0Zn, and 2.5Zn alloys, respectively) axe investigated. The results show that the Zn content not only influences grain refinement but also induces different phase precipitation behaviors. The as-cast microstxucture of the 0.6Zn alloy is composed of ct-Mg, Mg2Ca, and Ca2Mg6Zn3 phases, whereas 2.0Zn and 2.5Zn alloys only contain ct-Mg and Ca2Mg6Zn3 phases, as revealed by X-ray diffraction (XRD) and txonsmission electron microscopy (TEM) analyses. Moreover, with in- creasing Zn content, both the ultimate tensile strength (UTS) and the elongation to fracture first increase and then decrease. Among the three investigated alloys, the largest UTS (178 MPa) and the highest elongation to fracture (6.5%) are obtained for the 2.0Zn alloy. In addition, the corrosion rate increases with increasing Zn content. This paper provides on updated investigation of the alloy composi- tion-microstxucture-property relationships of different Zn-containing Mg-Zn-Ca alloys.
文摘The interactions of Sn and S and their effects on the magnetic properties of non-oriented silicon steel sheets were discussed in reference to industrial production. Results show that minor amounts of Sn can improve magnetic induction sharply but have little effect on core loss when the S content is below 10 × 10 ^-4%. The precipitation of AlN can be restrained effectively by Sn. Sn, as the nucleus, can remove some of the inclusions with a size of 0.5μm or larger, but has little effect on inclusions smaller than 0.5 μm,which is the key factor affecting core loss. Sn improves the magnetic induction of finished steel sheets mainly through the change of the steel texture. The relationship between the magnetic induction and Sn and S content can be regressed as B50 = 1.69 -4.37 ws +0.30 Ws,. From the regression formulation,the magnetic induction can be improved by 0.03 T when 0.01% Sn is added under relatively low S content conditions.
基金the financial support for this research from the National High-Tech R&D Program of China (2012AA101404)the National Natural Science Foundation of China (51209208, 51479201)
文摘The ecological effect of reclaimed water irrigation and fertilizer application on the soil environment is receiving more attention.Soil microbial activity and nitrogen(N)levels are important indicators of the effect of reclaimed water irrigation on environment.This study evaluated soil physicochemical properties and microbial community structure in soils irrigated with reclaimed water and receiving varied amounts of N fertilizer.The results indicated that the reclaimed water irrigation increased soil electrical conductivity(EC)and soil water content(SWC).The N treatment has highly significant effect on the ACE,Chao,Shannon(H)and Coverage indices.Based on a 16S ribosomal RNA(16S rRNA)sequence analysis,the Proteobacteria,Gemmatimonadetes and Bacteroidetes were more abundant in soil irrigated with reclaimed water than in soil irrigated with clean water.Stronger clustering of microbial communities using either clean or reclaimed water for irrigation indicated that the type of irrigation water may have a greater influence on the structure of soil microbial community than N fertilizer treatment.Based on a canonical correspondence analysis(CCA)between the species of soil microbes and the chemical properties of the soil,which indicated that nitrate N(NO3-–-N)and total phosphorus(TP)had significant impact on abundance of Verrucomicrobia and Gemmatimonadetes,meanwhile the p H and organic matter(OM)had impact on abundance of Firmicutes and Actinobacteria significantly.It was beneficial to the improvement of soil bacterial activity and fertility under 120 mg kg^-1 N with reclaimed water irrigation.
基金Supported by State Key Laboratory of Advanced Power Transmission Technology(GEIRI-SKL-2018-005)Guangzhou Major Industrial Technology Research Plan(201802010022)Guangzhou Science and Technology Project(201710010186)。
文摘The self-healing microcapsules can be buried in the coating to improve the anticorrosive ability.In this paper,self-healing microcapsules of polyurea(PU)/melamine resin(MF)double shell were prepared by in-situ polymerization and interfacial polymerization with isocyanate as the core material.Scanning electron microscope was used to observe the microcapsule morphology.The structures of microcapsules prepared with different chain extenders were characterized by Fourier transform infrared spectroscopy.The micromanipulation system was used to loading–holding,loading–unloading and loading to rupture individual microcapsules,so as to explore the mechanical properties of microcapsules.The Young’s modulus corresponding to microcapsules was calculated by mathematical model fitting.The self-healing properties of microcapsule coating were characterized by optical microscope.The experimental results showed that the microcapsule shell prepared under optimized conditions had a complete morphology and good mechanical properties.The microcapsule was in the elastic deformation stage under small deformation,and the plastic deformation stage under large deformation.The Young’s modulus range of microcapsules was 9.29–14.51 MPa,and the corresponding Young’s modulus could be prepared by adjusting the process.The surface crack of the coating containing microcapsule could heal itself after48 h in a humid environment.
基金Supported by the Natural Science Foundation of Shandong Province,China(ZR2010CQ017)Program of Young Teachers Development of Shandong University of Technology~~
文摘A yeast strain R6 was obtained by the method of thiamine(VB1) auxotrophic negative selection from the edible oil-polluted soil in Zibo, China. Physiological and biochemical experiments revealed that strain R6 shared common feature with Rhodotorula mucilaginosa according to the API 20 C AUX yeast identification system which has been tested previously. Furthermore, the 18 S r DNA gene of strain R6 was amplified and sequenced. Phylogenetic analysis based on the 18 S r DNA sequence and the relatives indicated that R6 shared 99% homologies with the members of R. mucilaginosa, suggesting that strain R6 belonged to R. mucilaginosa.Investigation showed that strain R6 possessed the capacity of accumulating exocellular alpha-ketoglutaric acid(alpha-KG). Finally, the fermentation conditions of R6 to accumulate alpha-KG was optimized by controlling each single fermenting variable and detected through high performance liquid chromatography(HPLC). Results showed that both VB1 and Ca CO3 in fermentation medium were the key factors influencing the cumulant of alpha-KG. The discovery of natural auxotrophic strain R6 not only broadened the microbial resource which can achieve lots of alpha-KG production through fermentation, but also laid a foundation for further fermentation regulation to achieve excessive alpha-KG accumulation.
基金Project(51578272)supported by the National Natural Science Foundation of China
文摘Calcined ginger nuts admixed by fly ash and quartz sand (CGN-(F+S)) has been validated to be basically compatible to earthen sites as an anchor grout. Accelerated ageing tests including water stability test, temperature and humidity cycling test, soundness test and alkali resistance test are conducted with the objective to further research the property changes of CGN-(F+S) grout. Density, surface hardness, water penetration capacity, water permeability capacity, soluble salt, scanning electron microscopy (SEM) images and energy dispersive spectrometry (EDS) spectrum of these samples have been tested after accelerated ageing tests. The results show that densities of samples decrease, surface hardness, water penetration capacity and water permeability capacity of samples increase generally. Besides, soluble salt analysis, SEM and EDS results well corroborate the changes. Based on the results it can be concluded that property changes are most serious after temperature and humidity cycling test, followed by water stability, soundness and alkali resistance test in sequence. But in general, CGN-(F+S) still has good durability.
基金Projects 50225414 and 50574090 supported by National Natural Science Fund for Distinguished Young Scholars, and 105024 supported by the Key Projectof Educational Ministry
文摘By using the steady-state seepage method, a patent seepage device together with the MTS815.02 Rock Mechanics Test System is used to test the seepage properties of non-Darcy flow in a granular gangue with five different grain sizes during the compaction. The experimental results show that the seepage properties are not only related to the stress or displacement level, but also to the grain size, the pore structure of the granular gangue, and the current porosity The permeability and the non-Darcy flow coefficient can be fitted respectively by the cubic polynomials and the power functions of the porosity, Formally, the flow in granular gangue satisfies the Forchheimer's binomial flow, but under the great axial and confining pressure and owing to the grain's crushing, the flow in granular gangues is different from that in rock-fills which are naturallv oiled un. As a result, the non-Darer flow coefficient may be negative.
文摘An excellent organic blue light-emitting diode based on 4,4'-bis(diphenylamino)-quinque(p-phenylene)s (OPP(5)-NPh) with a maximum luminance of up to 5000 cd/m^2 and a luminanous efficiency of 1.3 cd/A was reported. This diode was made by using a wide band-gap hole-blocking layer, F-TBB instead of PBD in the OLED devices. We attribute the good performance to the one trade-off involved in the use of F-TBB to obtain higher luminance is the increased turn-on voltages and slightly decreased device efficiencies.
基金Supported by the National Natural Science Fund ( 20276056)Special Fund of Education Department of Shaanxi Province (03JK190)
文摘Utilized degradable data of coal-filled films from the accelerated UV chamber ageing degradation experiments, and on the basis of control factors’ analysis, presented a predicting model on degradable properties of this film in photo-degradation according to back-propagation artificial neural network (BP ANN). 4 controlling factors in films degrada-tion, including temperature, the time of UV irradiation, the concentration and the type of coals were used as input parameters in the ANN model. While the degradable properties after film degradation, including the mechanical properties and carbonyl index, were used as output parameters. It was carried out by the neural network toolbox of Matlab 6.5 soft-ware and Visual Basic 6.0. Discussed partition of sample data and model’s parameters, and then selected the best configuration of ANN network. The accurate scope of predicting results was analyzed. This model has a high precision in predicting on properties of the coal-filled film degradation.
基金the Deanship of Scientific Research at King Saud University for funding this Research group No.RG 1435-004
文摘Structural, electronic, and optical properties of alloys BexMgl-xX (X = S, Se, Te) in the assortment 0 〈 x 〈 1 were theoretically reported for the first time in zinc-blende (ZB) phase. The calculations were carried out by using full-potential linearized augmented plane wave plus local orbitals (FP-LAPW+lo) formalism contained by the framework of density functional theory (DFT). Wu--Cohen (WC) generalized gradient approximation (GGA), based on optimization energy, has been applied to calculate these theoretical results. In addition, we used Becke and Johnson (mBJ-GGA) potential, modified form of GGA functional, to calculate electronic structural properties up to a high precision degree. The alloys were composed with the concentrations x = 0.25, 0.5, and 0.75 in pursuance of 'special quasi-random structures' (SQS) approach of Zunger for the restoration of disorder around the observed site of alloys in the first few shells. The structural parameters have been predicted by minimizing the total energy in correspondence of unit cell volume. Our alloys established direct band gap at different concentrations that make their importance in optically active materials. Furthermore, density of states was discussed in terms of the contribution of Be and Mg s and chalcogen (S, Se, and Te) s and p states and observed charge density helped us to investigate the bonding nature. By taking into consideration of immense importance in optoelectronics of these materials, the complex dielectric function was calculated for incident photon energy in the range 0--15 eV.
基金Project supported by the Cultivation Fund of the Key Scientific and Technical Innovation Project,Ministry of Education of China(Grant No.708068)the Specialized Research Fund for the Doctoral Program of Higher Education,Ministry of Education of China(Grant No.200805301001)the Open Fund based on Innovation Platform of Hunan Colleges and Universities,China (Grant No.09K034)
文摘The transport properties of hexagonal boron-nitride nanoribbons under the uniaxial strain are investigated by the Green's function method. We find that the transport properties of armchair boron-nitride nanoribbon strongly depend on the strain. In particular, the features of the conductance steps such as position and width are significantly changed by strain. As a strong tensile strain is exerted on the nanoribbon, the highest conductance step disappears and subsequently a dip emerges instead. The energy band structure and the local current density of armchair boron nitride nanoribbon under strain are calculated and analysed in detail to explain these characteristics. In addition, the effect of strain on the conductance of zigzag boron-nitride nanoribbon is weaker than that of armchair boron nitride nanoribbon.
基金Natural Science and Education Foundation of Henan Province(2007110016)
文摘In this paper, let T be a bounded linear operator on a complex Hilbert H. We give and prove that every p-w-hyponormal operator has Bishop's property(β) and spectral properties; Quasi-similar p-w-hyponormal operators have equal spectra and equal essential spectra. Finally, for p-w-hyponormal operators, we give a kind of proof of its normality by use of properties of partial isometry.