This paper intends to introduce and explain a deconstructionist approach to translation with the discussion on Walter Benjamin’s The Task of the Translator by Derrida, Paul De Man and Andrew Benjamin as the main them...This paper intends to introduce and explain a deconstructionist approach to translation with the discussion on Walter Benjamin’s The Task of the Translator by Derrida, Paul De Man and Andrew Benjamin as the main theme. Through our discussion, we have come to the conclusion that though deconstructionists approach translation in an attempt to expound their philosophical thinking on language instead of translation theory itself, their ideas might broaden our mind on translation and its related problems. [展开更多
This paper presents a scheme for quantum secure direct communication with quantum encryption. The two authorized users use repeatedly a sequence of the pure entangled pairs （quantum key） shared for encrypting and de...This paper presents a scheme for quantum secure direct communication with quantum encryption. The two authorized users use repeatedly a sequence of the pure entangled pairs （quantum key） shared for encrypting and decrypting the secret message carried by the travelling photons directly. For checking eavesdropping, the two parties perform the single-photon measurements on some decoy particles before each round. This scheme has the advantage that the pure entangled quantum signal source is feasible at present and any eavesdropper cannot steal the message.展开更多
The properties of water and their changes under the action of a magnetic field were gathered by the spectrum techniques of infrared, Raman, visible, ultraviolet and X-ray lights, which may give an insight into molecul...The properties of water and their changes under the action of a magnetic field were gathered by the spectrum techniques of infrared, Raman, visible, ultraviolet and X-ray lights, which may give an insight into molecular and atomic structures of water. It was found that some properties of water were changed, and a lot of new and strange phenomena were discovered after magnetization. Magnetized water really has magnetism, which has been verified by a peak shift of X-ray diffraction of magnetized water + Fe3O4 hybrid relative to that of pure water + Fe3O4 hybrid, that is a saturation and memory effect. The properties of infrared and ultraviolet absorptions, Raman scattering and X-ray diffraction of magnetized water were greatly changed relative to those of pure water; their strengths of peaks were all increased, the frequencies of some peaks did also shift, and some new peaks, for example, at 5198, 8050 and 9340 cm?1, occurred at 25°C after water was magnetized. In the meanwhile, the magnetized effects of water are related to the magnetized time, the intensity of an externally applied magnetic field, and the temperature of water, but they are not a linear relationship. The study also showed a lot of new and unusual properties of magnetized water, for example, the six peaks in 3000–3800 cm?1 in infrared absorption, the exponential increase of ultraviolet absorption of wave with the decreasing wavelength of light of 200–300 nm, the frequency-shifts of peaks, a strange irreversible effect in the increasing and decreasing processes, as well as a stronger peak of absorption occurring at 50°C, 70°C and 80°C, the existence of many models of motion from 85°C to 95°C in 8000–10000 cm?1, and so on. These results show that the molecular structure of water is very complicated, which needs further study. Furthermore, the macroscopic feature of mechanics, for instance, surface tension force of magnetized water, was also measured. Experiments discovered that the size in contact angles of magnetized water on the surface展开更多
As an important development direction of pure electric vehicle drive system,the distributed drive system has the advantages of compact structure,high transmission efficiency,and flexible control,but there are some ser...As an important development direction of pure electric vehicle drive system,the distributed drive system has the advantages of compact structure,high transmission efficiency,and flexible control,but there are some serious problems such as high performance requirements to the drive motors,complex control strategies,and poor reliability.To solve these problems,a two motors dual-mode coupling drive system has been developed at first,which not only has the capacity of two-speed gear shifting,but also can automatically switch between the distributed drive and the centralized drive by means of modes change control.So,the performance requirements to the drive motors can be reduced,the problem of abnormal running caused by the fault of unilateral distributed drive systems also can be resolved by replacing the drive mode with centralized drive.Then,the system parameters primary and the optimum matching under the principle of efficiency optimization have been carried out,which makes the drive system achieve predetermined functions and meet the actual demands of different operating statuses.At last,the economic comparison of a pure electric vehicle installation with a dual-mode coupling drive sytem,a single-motor centralized drive system or a dual-motor distributed drive system in the simulation conditions has been completed.Compared with other systems,the driving range of the electric vehicle driven by the designed system is significantly increased,which proves the better efficiency and application value of the system.展开更多
Unlike inorganic quantum dots,fluorescent graphene quantum dots(GQDs)display excitation-dependent multiple color emission.In this study,we report N-doped GQDs(N-GQDs)with tailored single color emission by tuning p-con...Unlike inorganic quantum dots,fluorescent graphene quantum dots(GQDs)display excitation-dependent multiple color emission.In this study,we report N-doped GQDs(N-GQDs)with tailored single color emission by tuning p-conjugation degree,which is comparable to the inorganic quantum dot.Starting from citric acid and diethylenetriamine,as prepared N-GQDs display blue,green,and yellow light emission by changing the reaction solvent from water,dimethylformamide(DMF),and solvent free.The X-ray photoelectron spectroscopy,ultraviolet-visible spectra results clearly show the N-GQDs with blue emission(N-GQDs-B)have relatively short effective conjugation length and more carboxyl group because H_(2)O is a polar protic solvent,which tends to donate proton to the reagent to depress the H_(2)O elimination reaction.On the other hand,the polar aprotic solvent(DMF)cannot donate hydrogen,the elimination of H_(2)O is promoted and more nitrogen units enter GQD framework.With the increase of effective p-conjugation length and N content,the emission band of N-GQDS red-shifts to green and yellow.We also demonstrate that N-GQDs could be a potential great biomarker for fluorescent bioimaging.展开更多
Published results on the growth interactions of non-nitrogen fixing mixed plantations species, and their impact on the regeneration of woody plants are scant. This paper addresses the growth interactions of pure and m...Published results on the growth interactions of non-nitrogen fixing mixed plantations species, and their impact on the regeneration of woody plants are scant. This paper addresses the growth interactions of pure and mixed plantations of Eucalyptus camaldulensis and Cupressus lusitanica and their impact on the regeneration of woody plants in relation with light. Data on the regenerated woody plants, individual characteristics of the plantation species and light reaching under the canopies were collected using sample plots (n = 4) with a size of 20 m × 20 m for each plantation type. The result showed that, E. camaldulensis was suppressing the growth of C. lusitanica while its growth was favored when it was mixed with C. lusitanica (p < 0.05). There were no significant differences between the pure and mixed plantations in their diversity and density of undergrowth woody plants (p > 0.05). Density of plantation trees were found not having a significant relationship with diversity of species (p = 0.801). There was a significant but not direct relationship between light reached in the understory of the canopies and diversity of species in the plantations (p = 0.027). Overall, the result indicated that both the pure and the mixed plantations were favoring the recruitment of woody plants.展开更多
The effects of cold rolling and annealing on the microstructure and textural evolution of a commercially pure titanium（CP-Ti） sheet were investigated. Electron backscatter diffractometry demonstrates that the deform...The effects of cold rolling and annealing on the microstructure and textural evolution of a commercially pure titanium（CP-Ti） sheet were investigated. Electron backscatter diffractometry demonstrates that the deformation during rolling is accommodated by twinning and slip. Additionally, twinning is the dominant deformation mechanism when the cold rolling reduction is less than 40%. During rolling, {11ˉ22}11ˉ2ˉ3contraction twinning（CT） and {10ˉ12}10ˉ11 extension twinning（ET） are activated. And, the intensity of the（0002） pole along the ND gradually increases with increasing deformation. During annealing, the fraction of low angle grain boundaries（LAGBs） and the intensity of the（0002） pole along the ND gradually decrease slightly with increasing annealing time, while twinning lamellae disappear rapidly. When the annealing time reaches 60 min, 20% cold-rolled sheet recrystallizes almost completely.展开更多
As-cast Cu-La alloys with La contents in the range of 0–0.32 wt.% were fabricated by vacuum melting method. The effects of La on microstructure and mechanical properties of as-cast pure copper were investigated using...As-cast Cu-La alloys with La contents in the range of 0–0.32 wt.% were fabricated by vacuum melting method. The effects of La on microstructure and mechanical properties of as-cast pure copper were investigated using optical microscopy（OM）, scanning electronic microscopy（SEM）, transmission electron microscopy（TEM）, X-ray diffraction（XRD） and tensile test. The results showed that La had obvious effects on the solidification microstructure and the grain refinement of as-cast pure copper. With the increase of La content, the ultimate tensile strength, the yield strength and the microhardness increased gradually, but the elongation increased first and then decreased while La content exceeded 0.089 wt.%. The improvement of mechanical properties was attributed to the effect of grain refinement strengthening, solid solution strengthening, second phase strengthening and purifying. However, excessive adding La would deteriorate the elongation owing to the excessive Cu6 La phases.展开更多
High-performance white light-emitting diodes (WLEDs) hold great potential for the next-generation backlight display applications.However,achieving highly efficient and stable WLEDs with wide-color-gamut has remained a...High-performance white light-emitting diodes (WLEDs) hold great potential for the next-generation backlight display applications.However,achieving highly efficient and stable WLEDs with wide-color-gamut has remained a formidable goal.Reported here is the first example of pure red narrow bandwidth emission triangular CQDs (PR-NBE-T-CQDs) with photoluminescence peaking at 610 nm.The PR-NBE-T-CQDs synthesized from resorcinol show high quantum yield (QY) of 72% with small full width at half maximum of 33 nm.By simply controlling the reaction time,pure green (PG-) NBE-T-CQDs with high QY of 75% were also obtained.Highly efficient and stable WLEDs with wide-color-gamut based on PR- and PG-NBE-T-CQDs was achieved.This WLED showed a remarkable wide-color gamut of 110% NTSC and high power efficiency of 86.5 lumens per Watt.Furthermore,such WLEDs demonstrate outstanding stability.This work will set the stage for developing highly efficient,low cost and environment-friendly WLEDs based on CQDs for the next-generation wide-color gamut backlight displays.展开更多
Principle on temperature response to the stress-strain variation is fundamental to the relationship between thermal radiation variation and stress-strain field. Current research indicates that temperature has a sensit...Principle on temperature response to the stress-strain variation is fundamental to the relationship between thermal radiation variation and stress-strain field. Current research indicates that temperature has a sensitive response to rock deformation under the condition of normal temperature background. However, the basic physical relationship between deformation and temperature variation is not clear and need to be investigated further. In this paper, principle on temperature response to stress-strain variation is studied in detail, based on thermodynamics, elastic strain theory, and experiments on both ideal material and rock. In the stage of elastic deformation, results indicate that: 1) temperature increment is positively correlated with volume strain variation. Temperature rises with hydrostatic pressure increase. In other words, temperature rises when the specimen is under the compressive state whereas temperature drops under the tensile state. 2) Pure shear deformation does not contribute to tempera- ture variation. Namely, shape change of specimen does not produce temperature variation. However, there exist the relative tensile area and the compressive one in the specimen under the state of pure shear. Temperature drops within the relative tensile area while temperature rises within the compressive areas during the process of loading.展开更多
The effects of a pulsed magnetic field on the solidified microstructure of pure Mg were investigated.The results show that microstructure of pure Mg is considerably refined via columnar-to-equiaxed growth under the pu...The effects of a pulsed magnetic field on the solidified microstructure of pure Mg were investigated.The results show that microstructure of pure Mg is considerably refined via columnar-to-equiaxed growth under the pulsed magnetic field and the average grain size is refined to 260？？ under the optimal processing conditions.A mathematical model was built to describe the interaction of the electromagnetic-flow fields during solidification with ANSYS software.The pulsed electric circuit was first solved and then it is substituted into the magnetic field model.The fluid flow model was solved with the acquired electromagnetic force.The effects of pulse voltage frequency on the current wave and on the distribution of magnetic and flow fields were numerically studied.The pulsed magnetic field increases melt convection,which stirs and fractures the dendritic arms into pieces.These broken pieces are transported into the bulk liquid by the liquid flow and act as nuclei to enhance grain refinement.The Joule heat effect produced by the electric current also participates in the microstructural refinement.展开更多
Starting from Witten’s eleven dimensional M-theory, the present work develops in an analogous way a corresponding dimensional fractal version where . Subsequently, the new fractal formalism is utilized to determine t...Starting from Witten’s eleven dimensional M-theory, the present work develops in an analogous way a corresponding dimensional fractal version where . Subsequently, the new fractal formalism is utilized to determine the measured ordinary energy density of the cosmos which turns out to be intimately linked to the new theory’s fractal dimension via non-integer irrational Lorentzian-like factor: where is Hardy’s probability of quantum entanglement. Consequently, the energy density is found from a limiting classical kinetic energy to be Here, is ‘tHooft’s renormalon of dimensional regularization. The immediate logical, mathematical and physical implication of this result is that the dark energy density of the cosmos must be in astounding agreement with cosmic measurements and observations.展开更多
Two bacterial stains were isolated from the activated sludge and identified as Leucobacter sp. and Alcaligenesfaecalis by 16S rDNA sequencing. Pure cultures of these two strains, representing well or poorly settled ba...Two bacterial stains were isolated from the activated sludge and identified as Leucobacter sp. and Alcaligenesfaecalis by 16S rDNA sequencing. Pure cultures of these two strains, representing well or poorly settled bacteria, were used to investigate the mechanism of bioflocculation in activated sludge. Based on the analyses of the characteristics of cells hydrophobicity, ζ-potential, flocculation ability and extracellular polymeric substance （EPS） composition under different growth stages, it was found that the ratio of cell EPS protein had the highly influence on ζ-potential and hydrophobicity, which were important factors to bioflocculation. Cellulase and Proteinase K could destroy the extracellular biopolymer and resulted in a decrease in the hydrophobicity and ζ-potential. However, in our study, the flocculation characteristics exhibited differently in relation to cellulase and Proteinase K. Flocculation of cells treated with cellulase and Proteinase K decreased sharply, and then recovered quickly in cellulase treatment, while cells treated with Proteinase K showed no sign of recovery. This reveals that the presence of protein in extracellular biopolymer plays an important role to the bioflocculation of cells.展开更多
Poor corrosion resistance is one of the main disadvantages for biodegradable magnesium-based metals,especially applied for bone fixation,where there is a high demand of bio-mechanical strength and stability.Surface co...Poor corrosion resistance is one of the main disadvantages for biodegradable magnesium-based metals,especially applied for bone fixation,where there is a high demand of bio-mechanical strength and stability.Surface coating has been proved as an effective method to control the in vivo degradation.In this study a Ca-P self-sealing micro-arc oxidation(MAO)coating was studied to verify its efficacy and biological properties by in vitro and in vivo tests.It was found that the MAO coating could effectively retard the degradation according to immersion and electrochemical tests as well as 3D reconstruction by X-ray tomography after implantation.The MAO coating exhibited no toxicity and could stimulate the new bone formation.Therefore,the Ca-P self-sealing MAO coating could be a potential candidate for application of biodegradable Mg-based implant in bone fixations.展开更多
The biocorrosion of magnesium in the external physiological environment is still difficult to accurately evaluate the degradation behavior in vivo,particularly,in the microenvironment of the patients with hyperglycemi...The biocorrosion of magnesium in the external physiological environment is still difficult to accurately evaluate the degradation behavior in vivo,particularly,in the microenvironment of the patients with hyperglycemia or diabetes.Thus,we explored the synergistic effects of glucose and protein on the biodegradation of pure magnesium,so as to have a deeper understanding the mechanism of the degradation in vivo.The surface morphology and corrosion product composition of pure magnesium were investigated using SEM,EDS,FTIR,XRD and XPS.The effect of glucose and albumin on the degradation rate of pure magnesium was investigated via electrochemical and immersion tests.The adsorption of glucose and albumin on the sample surface was observed using fluorescence microscopy.The results showed that the presence of 2 g/L glucose changed the micromorphology of corrosion products on the magnesium surface by reacting with metal cations,thus inhibiting the corrosion of pure magnesium.Protein formed a barrier layer to protect the magnesium at early stage of immersion.The chelation reaction between protein and magnesium surface might accelerate the degradation at later stage.There may be a critical glucose(albumin)content.Biodegradation of pure magnesium was inhibited at low concentrations and promoted at high concentrations.The synergistic effect of glucose and protein restrained the adsorption of aggressive chloride ions to a certain extent,and thus inhibited the degradation of pure magnesium considerably.Moreover,XPS results indicated that glucose promoted the adsorption of protein on the sample surface.展开更多
The existing research about ductile grinding of fused silica glass was mainly focused on how to carry out ductile regime material removal for generating very ＂smoothed＂ surface and investigate the machining-induced ...The existing research about ductile grinding of fused silica glass was mainly focused on how to carry out ductile regime material removal for generating very ＂smoothed＂ surface and investigate the machining-induced damage in the grinding in order to reduce or eliminate the subsurface damage.The brittle/ductile transition behavior of optical glass materials and the wear of diamond wheel are the most important factors for ductile grinding of optical glass.In this paper,the critical brittle/ductile depth,the influence factors on brittle/ductile transition behavior,the wear of diamond grits in diamond grinding of ultra pure fused silica（UPFS） are investigated by means of micro/nano indentation technique,as well as single grit diamond grinding on an ultra-stiff machine tool,Tetraform ＂C＂.The single grit grinding processes are in-process monitored using acoustic emission（AE） and force dynamometer simultaneously.The wear of diamond grits,morphology and subsurface integrity of the machined groves are examined with atomic force microscope（AFM） and scanning electron microscope（SEM）.The critical brittle/ductile depth of more than 0.5 μm is achieved.When compared to the using roof-like grits,by using pyramidal diamonds leads to higher critical depths of scratch with identical grinding parameters.However,the influence of grit shapes on the critical depth is not significant as supposed.The grinding force increased linearly with depth of cut in the ductile removal regime,but in brittle removal regime,there are large fluctuations instead of forces increase.The SEM photographs of the cross-section profile show that the median cracks dominate the crack patterns beneath the single grooves.Furthermore,The SEM photographs show multi worn patterns of diamond grits,indicating an inhomogeneous wear mechanism of diamond grits in grinding of fused silica with diamond grinding wheels.The proposed research provides the basal technical theory for improving the ultra-precision grinding of UPFS.展开更多
Key Laboratory for Beam Technology and Materials Modification, Institute ofLow Energy Nuclear Physics, Beijing Normal UniversityThe morphology, composition, and phase structure of the oxide coatings produced on the su...Key Laboratory for Beam Technology and Materials Modification, Institute ofLow Energy Nuclear Physics, Beijing Normal UniversityThe morphology, composition, and phase structure of the oxide coatings produced on the surface ofpure titanium by alternating-current microarc discharge in aluminate solution were investigated byX-ray diffraction and scanning electron microscopy. The profiles of the hardness H and the elasticmodulus E in the coatings were determined using a nanoindentation method. The concentrationdistributions of Ti, Al, and O in the coating show that this coating over 30 mu m thick contains twolayers: an outer layer and an inner layer. The oxide coating is mainly composed of TiO_2 rutile andAl_2TiO_5 compounds. During oxidation, the temperature in the microarc discharge channel was veryhigh to make the local coating molten. From the surface to the interior of the coating, H and Eincrease gradually, and then reach maximum values of 9.78 GPa and 176 GPa respectively at a distanceof 7 mu m from the coating/titanium interface. They are also rather high near the interface.展开更多
文摘This paper intends to introduce and explain a deconstructionist approach to translation with the discussion on Walter Benjamin’s The Task of the Translator by Derrida, Paul De Man and Andrew Benjamin as the main theme. Through our discussion, we have come to the conclusion that though deconstructionists approach translation in an attempt to expound their philosophical thinking on language instead of translation theory itself, their ideas might broaden our mind on translation and its related problems. [
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10604008 and 10435020） and the Beijing Education Committee （Grant No XK100270454）.
文摘This paper presents a scheme for quantum secure direct communication with quantum encryption. The two authorized users use repeatedly a sequence of the pure entangled pairs （quantum key） shared for encrypting and decrypting the secret message carried by the travelling photons directly. For checking eavesdropping, the two parties perform the single-photon measurements on some decoy particles before each round. This scheme has the advantage that the pure entangled quantum signal source is feasible at present and any eavesdropper cannot steal the message.
基金the National Basic Research Program of China (Grant No. 2007CB936103)
文摘The properties of water and their changes under the action of a magnetic field were gathered by the spectrum techniques of infrared, Raman, visible, ultraviolet and X-ray lights, which may give an insight into molecular and atomic structures of water. It was found that some properties of water were changed, and a lot of new and strange phenomena were discovered after magnetization. Magnetized water really has magnetism, which has been verified by a peak shift of X-ray diffraction of magnetized water + Fe3O4 hybrid relative to that of pure water + Fe3O4 hybrid, that is a saturation and memory effect. The properties of infrared and ultraviolet absorptions, Raman scattering and X-ray diffraction of magnetized water were greatly changed relative to those of pure water; their strengths of peaks were all increased, the frequencies of some peaks did also shift, and some new peaks, for example, at 5198, 8050 and 9340 cm?1, occurred at 25°C after water was magnetized. In the meanwhile, the magnetized effects of water are related to the magnetized time, the intensity of an externally applied magnetic field, and the temperature of water, but they are not a linear relationship. The study also showed a lot of new and unusual properties of magnetized water, for example, the six peaks in 3000–3800 cm?1 in infrared absorption, the exponential increase of ultraviolet absorption of wave with the decreasing wavelength of light of 200–300 nm, the frequency-shifts of peaks, a strange irreversible effect in the increasing and decreasing processes, as well as a stronger peak of absorption occurring at 50°C, 70°C and 80°C, the existence of many models of motion from 85°C to 95°C in 8000–10000 cm?1, and so on. These results show that the molecular structure of water is very complicated, which needs further study. Furthermore, the macroscopic feature of mechanics, for instance, surface tension force of magnetized water, was also measured. Experiments discovered that the size in contact angles of magnetized water on the surface
基金supported by the National Key Technology R&D Program of the Ministry of Science and Technology(Grant No.2013BAG14B01)the Shandong Provincial Natural Science Foundation of China(Grant No.ZR2012EEL08)China Postdoctoral Science Foundation Funded Project(Grant No.2013M530608)
文摘As an important development direction of pure electric vehicle drive system,the distributed drive system has the advantages of compact structure,high transmission efficiency,and flexible control,but there are some serious problems such as high performance requirements to the drive motors,complex control strategies,and poor reliability.To solve these problems,a two motors dual-mode coupling drive system has been developed at first,which not only has the capacity of two-speed gear shifting,but also can automatically switch between the distributed drive and the centralized drive by means of modes change control.So,the performance requirements to the drive motors can be reduced,the problem of abnormal running caused by the fault of unilateral distributed drive systems also can be resolved by replacing the drive mode with centralized drive.Then,the system parameters primary and the optimum matching under the principle of efficiency optimization have been carried out,which makes the drive system achieve predetermined functions and meet the actual demands of different operating statuses.At last,the economic comparison of a pure electric vehicle installation with a dual-mode coupling drive sytem,a single-motor centralized drive system or a dual-motor distributed drive system in the simulation conditions has been completed.Compared with other systems,the driving range of the electric vehicle driven by the designed system is significantly increased,which proves the better efficiency and application value of the system.
基金The authors thank the National Natural Science Foundation of China(No.21301166,21201159,61306081,and 61176016)Science and Technology Department of Jilin Province(No.20130522127JH)are gratefully acknowledged+1 种基金ZS thanks the support of the‘Hundred Talent Program’of CAS and Innovation and Entrepreneurship Program of JilinThe project was supported by Open Research Fund of State Key Laboratory of Polymer Physics and Chemistry and the open research fund program of the State Key Laboratory of Luminescence and Applications.
文摘Unlike inorganic quantum dots,fluorescent graphene quantum dots(GQDs)display excitation-dependent multiple color emission.In this study,we report N-doped GQDs(N-GQDs)with tailored single color emission by tuning p-conjugation degree,which is comparable to the inorganic quantum dot.Starting from citric acid and diethylenetriamine,as prepared N-GQDs display blue,green,and yellow light emission by changing the reaction solvent from water,dimethylformamide(DMF),and solvent free.The X-ray photoelectron spectroscopy,ultraviolet-visible spectra results clearly show the N-GQDs with blue emission(N-GQDs-B)have relatively short effective conjugation length and more carboxyl group because H_(2)O is a polar protic solvent,which tends to donate proton to the reagent to depress the H_(2)O elimination reaction.On the other hand,the polar aprotic solvent(DMF)cannot donate hydrogen,the elimination of H_(2)O is promoted and more nitrogen units enter GQD framework.With the increase of effective p-conjugation length and N content,the emission band of N-GQDS red-shifts to green and yellow.We also demonstrate that N-GQDs could be a potential great biomarker for fluorescent bioimaging.
文摘Published results on the growth interactions of non-nitrogen fixing mixed plantations species, and their impact on the regeneration of woody plants are scant. This paper addresses the growth interactions of pure and mixed plantations of Eucalyptus camaldulensis and Cupressus lusitanica and their impact on the regeneration of woody plants in relation with light. Data on the regenerated woody plants, individual characteristics of the plantation species and light reaching under the canopies were collected using sample plots (n = 4) with a size of 20 m × 20 m for each plantation type. The result showed that, E. camaldulensis was suppressing the growth of C. lusitanica while its growth was favored when it was mixed with C. lusitanica (p < 0.05). There were no significant differences between the pure and mixed plantations in their diversity and density of undergrowth woody plants (p > 0.05). Density of plantation trees were found not having a significant relationship with diversity of species (p = 0.801). There was a significant but not direct relationship between light reached in the understory of the canopies and diversity of species in the plantations (p = 0.027). Overall, the result indicated that both the pure and the mixed plantations were favoring the recruitment of woody plants.
基金Projects(51505046,51421001)supported by the National Natural Science Foundation of China
文摘The effects of cold rolling and annealing on the microstructure and textural evolution of a commercially pure titanium（CP-Ti） sheet were investigated. Electron backscatter diffractometry demonstrates that the deformation during rolling is accommodated by twinning and slip. Additionally, twinning is the dominant deformation mechanism when the cold rolling reduction is less than 40%. During rolling, {11ˉ22}11ˉ2ˉ3contraction twinning（CT） and {10ˉ12}10ˉ11 extension twinning（ET） are activated. And, the intensity of the（0002） pole along the ND gradually increases with increasing deformation. During annealing, the fraction of low angle grain boundaries（LAGBs） and the intensity of the（0002） pole along the ND gradually decrease slightly with increasing annealing time, while twinning lamellae disappear rapidly. When the annealing time reaches 60 min, 20% cold-rolled sheet recrystallizes almost completely.
基金Project supported by Science Foundation of The Chinese Academy of Sciences
文摘As-cast Cu-La alloys with La contents in the range of 0–0.32 wt.% were fabricated by vacuum melting method. The effects of La on microstructure and mechanical properties of as-cast pure copper were investigated using optical microscopy（OM）, scanning electronic microscopy（SEM）, transmission electron microscopy（TEM）, X-ray diffraction（XRD） and tensile test. The results showed that La had obvious effects on the solidification microstructure and the grain refinement of as-cast pure copper. With the increase of La content, the ultimate tensile strength, the yield strength and the microhardness increased gradually, but the elongation increased first and then decreased while La content exceeded 0.089 wt.%. The improvement of mechanical properties was attributed to the effect of grain refinement strengthening, solid solution strengthening, second phase strengthening and purifying. However, excessive adding La would deteriorate the elongation owing to the excessive Cu6 La phases.
基金supported by the National Natural Science Foundation of China (NSFC)(Nos.21573019 and 21872010)the Major Research Plan of the National Natural Science Foundation of China (No.21233003)the Fundamental Research Funds for the Central Universities.
文摘High-performance white light-emitting diodes (WLEDs) hold great potential for the next-generation backlight display applications.However,achieving highly efficient and stable WLEDs with wide-color-gamut has remained a formidable goal.Reported here is the first example of pure red narrow bandwidth emission triangular CQDs (PR-NBE-T-CQDs) with photoluminescence peaking at 610 nm.The PR-NBE-T-CQDs synthesized from resorcinol show high quantum yield (QY) of 72% with small full width at half maximum of 33 nm.By simply controlling the reaction time,pure green (PG-) NBE-T-CQDs with high QY of 75% were also obtained.Highly efficient and stable WLEDs with wide-color-gamut based on PR- and PG-NBE-T-CQDs was achieved.This WLED showed a remarkable wide-color gamut of 110% NTSC and high power efficiency of 86.5 lumens per Watt.Furthermore,such WLEDs demonstrate outstanding stability.This work will set the stage for developing highly efficient,low cost and environment-friendly WLEDs based on CQDs for the next-generation wide-color gamut backlight displays.
基金Supported by Basic Research Funds from Institute of Geology,China Earthquake Administration (Grant No. DF-IGCEA-0607-1-5)National Natural Science Founda-tion of China (Grant Nos. 40572125, 90202018) Special Funds for Social Public of Ministry of Science and Technology (Grant No. 2004DIB3J129)
文摘Principle on temperature response to the stress-strain variation is fundamental to the relationship between thermal radiation variation and stress-strain field. Current research indicates that temperature has a sensitive response to rock deformation under the condition of normal temperature background. However, the basic physical relationship between deformation and temperature variation is not clear and need to be investigated further. In this paper, principle on temperature response to stress-strain variation is studied in detail, based on thermodynamics, elastic strain theory, and experiments on both ideal material and rock. In the stage of elastic deformation, results indicate that: 1) temperature increment is positively correlated with volume strain variation. Temperature rises with hydrostatic pressure increase. In other words, temperature rises when the specimen is under the compressive state whereas temperature drops under the tensile state. 2) Pure shear deformation does not contribute to tempera- ture variation. Namely, shape change of specimen does not produce temperature variation. However, there exist the relative tensile area and the compressive one in the specimen under the state of pure shear. Temperature drops within the relative tensile area while temperature rises within the compressive areas during the process of loading.
基金Project(50774075)supported by the National Natural Science Foundation of ChinaProject(2006BAE04B01-4)supported by Key Technologies R&D Program,China
文摘The effects of a pulsed magnetic field on the solidified microstructure of pure Mg were investigated.The results show that microstructure of pure Mg is considerably refined via columnar-to-equiaxed growth under the pulsed magnetic field and the average grain size is refined to 260？？ under the optimal processing conditions.A mathematical model was built to describe the interaction of the electromagnetic-flow fields during solidification with ANSYS software.The pulsed electric circuit was first solved and then it is substituted into the magnetic field model.The fluid flow model was solved with the acquired electromagnetic force.The effects of pulse voltage frequency on the current wave and on the distribution of magnetic and flow fields were numerically studied.The pulsed magnetic field increases melt convection,which stirs and fractures the dendritic arms into pieces.These broken pieces are transported into the bulk liquid by the liquid flow and act as nuclei to enhance grain refinement.The Joule heat effect produced by the electric current also participates in the microstructural refinement.
文摘Starting from Witten’s eleven dimensional M-theory, the present work develops in an analogous way a corresponding dimensional fractal version where . Subsequently, the new fractal formalism is utilized to determine the measured ordinary energy density of the cosmos which turns out to be intimately linked to the new theory’s fractal dimension via non-integer irrational Lorentzian-like factor: where is Hardy’s probability of quantum entanglement. Consequently, the energy density is found from a limiting classical kinetic energy to be Here, is ‘tHooft’s renormalon of dimensional regularization. The immediate logical, mathematical and physical implication of this result is that the dark energy density of the cosmos must be in astounding agreement with cosmic measurements and observations.
基金supported by the National Natural Science Foundation of China(No. 20977031)the Natural Science Foundation of Shanghai(No. 09zr1409000)+2 种基金the Research Initiatives of the University of Hong Kong(2006)the Royal Society of New Zealand(ISAT B09-33)Faculty of Health & Environmental Sciences,Auckland University of Technology
文摘Two bacterial stains were isolated from the activated sludge and identified as Leucobacter sp. and Alcaligenesfaecalis by 16S rDNA sequencing. Pure cultures of these two strains, representing well or poorly settled bacteria, were used to investigate the mechanism of bioflocculation in activated sludge. Based on the analyses of the characteristics of cells hydrophobicity, ζ-potential, flocculation ability and extracellular polymeric substance （EPS） composition under different growth stages, it was found that the ratio of cell EPS protein had the highly influence on ζ-potential and hydrophobicity, which were important factors to bioflocculation. Cellulase and Proteinase K could destroy the extracellular biopolymer and resulted in a decrease in the hydrophobicity and ζ-potential. However, in our study, the flocculation characteristics exhibited differently in relation to cellulase and Proteinase K. Flocculation of cells treated with cellulase and Proteinase K decreased sharply, and then recovered quickly in cellulase treatment, while cells treated with Proteinase K showed no sign of recovery. This reveals that the presence of protein in extracellular biopolymer plays an important role to the bioflocculation of cells.
基金This work was financially supported by National Basic Research program of China(973 program,No.2012CB619101)Innovative R&D Team of Biodegradable Magnesium Alloy and Related Implanted Device(No.201001C0104669453).
文摘Poor corrosion resistance is one of the main disadvantages for biodegradable magnesium-based metals,especially applied for bone fixation,where there is a high demand of bio-mechanical strength and stability.Surface coating has been proved as an effective method to control the in vivo degradation.In this study a Ca-P self-sealing micro-arc oxidation(MAO)coating was studied to verify its efficacy and biological properties by in vitro and in vivo tests.It was found that the MAO coating could effectively retard the degradation according to immersion and electrochemical tests as well as 3D reconstruction by X-ray tomography after implantation.The MAO coating exhibited no toxicity and could stimulate the new bone formation.Therefore,the Ca-P self-sealing MAO coating could be a potential candidate for application of biodegradable Mg-based implant in bone fixations.
基金supported by the National Natural Science Foundation of China(51571134)the Scientific Research Foundation of Shandong University of Science and Technology Research Fund(2014TDJH104)Undergraduate Innovation and Entrepreneurship Training Program of Shandong University of Science and Technology(201710424082).
文摘The biocorrosion of magnesium in the external physiological environment is still difficult to accurately evaluate the degradation behavior in vivo,particularly,in the microenvironment of the patients with hyperglycemia or diabetes.Thus,we explored the synergistic effects of glucose and protein on the biodegradation of pure magnesium,so as to have a deeper understanding the mechanism of the degradation in vivo.The surface morphology and corrosion product composition of pure magnesium were investigated using SEM,EDS,FTIR,XRD and XPS.The effect of glucose and albumin on the degradation rate of pure magnesium was investigated via electrochemical and immersion tests.The adsorption of glucose and albumin on the sample surface was observed using fluorescence microscopy.The results showed that the presence of 2 g/L glucose changed the micromorphology of corrosion products on the magnesium surface by reacting with metal cations,thus inhibiting the corrosion of pure magnesium.Protein formed a barrier layer to protect the magnesium at early stage of immersion.The chelation reaction between protein and magnesium surface might accelerate the degradation at later stage.There may be a critical glucose(albumin)content.Biodegradation of pure magnesium was inhibited at low concentrations and promoted at high concentrations.The synergistic effect of glucose and protein restrained the adsorption of aggressive chloride ions to a certain extent,and thus inhibited the degradation of pure magnesium considerably.Moreover,XPS results indicated that glucose promoted the adsorption of protein on the sample surface.
基金supported by National Key Science and Technology Projects of China (Grant No. 2009ZX04001-101, Grant No. 2009ZX01001-151)New Century Excellent Talents in University,China (GrantNo. NCET-07-0246)National Natural Science Foundation of China(Grant No. 50675051)
文摘The existing research about ductile grinding of fused silica glass was mainly focused on how to carry out ductile regime material removal for generating very ＂smoothed＂ surface and investigate the machining-induced damage in the grinding in order to reduce or eliminate the subsurface damage.The brittle/ductile transition behavior of optical glass materials and the wear of diamond wheel are the most important factors for ductile grinding of optical glass.In this paper,the critical brittle/ductile depth,the influence factors on brittle/ductile transition behavior,the wear of diamond grits in diamond grinding of ultra pure fused silica（UPFS） are investigated by means of micro/nano indentation technique,as well as single grit diamond grinding on an ultra-stiff machine tool,Tetraform ＂C＂.The single grit grinding processes are in-process monitored using acoustic emission（AE） and force dynamometer simultaneously.The wear of diamond grits,morphology and subsurface integrity of the machined groves are examined with atomic force microscope（AFM） and scanning electron microscope（SEM）.The critical brittle/ductile depth of more than 0.5 μm is achieved.When compared to the using roof-like grits,by using pyramidal diamonds leads to higher critical depths of scratch with identical grinding parameters.However,the influence of grit shapes on the critical depth is not significant as supposed.The grinding force increased linearly with depth of cut in the ductile removal regime,but in brittle removal regime,there are large fluctuations instead of forces increase.The SEM photographs of the cross-section profile show that the median cracks dominate the crack patterns beneath the single grooves.Furthermore,The SEM photographs show multi worn patterns of diamond grits,indicating an inhomogeneous wear mechanism of diamond grits in grinding of fused silica with diamond grinding wheels.The proposed research provides the basal technical theory for improving the ultra-precision grinding of UPFS.
文摘Key Laboratory for Beam Technology and Materials Modification, Institute ofLow Energy Nuclear Physics, Beijing Normal UniversityThe morphology, composition, and phase structure of the oxide coatings produced on the surface ofpure titanium by alternating-current microarc discharge in aluminate solution were investigated byX-ray diffraction and scanning electron microscopy. The profiles of the hardness H and the elasticmodulus E in the coatings were determined using a nanoindentation method. The concentrationdistributions of Ti, Al, and O in the coating show that this coating over 30 mu m thick contains twolayers: an outer layer and an inner layer. The oxide coating is mainly composed of TiO_2 rutile andAl_2TiO_5 compounds. During oxidation, the temperature in the microarc discharge channel was veryhigh to make the local coating molten. From the surface to the interior of the coating, H and Eincrease gradually, and then reach maximum values of 9.78 GPa and 176 GPa respectively at a distanceof 7 mu m from the coating/titanium interface. They are also rather high near the interface.
