Lattice preferred orientation （LPO） and seismic anisotropy of orthopyroxene （enstatite） in mantle xenoliths from Spitsbergen, Svalbard, near the Arctic, are studied. LPOs of enstatite were determined using electro...Lattice preferred orientation （LPO） and seismic anisotropy of orthopyroxene （enstatite） in mantle xenoliths from Spitsbergen, Svalbard, near the Arctic, are studied. LPOs of enstatite were determined using electron backseattered diffraction （EBSD）. We found four types of LPOs of orthopyroxene and defined them as type-AC, -AB, -BC, and -ABC. Type-AC LPO of orthopyroxene is defined as （100） plane aligned subparallel to foliation and [001] axis aligned subparallel to lineation. Type-AB LPO is defined as （100） plane aligned subparallel to foliation and [010] axis aligned subparallel to linea- tion. Type-BC LPO is defined as （010） plane aligned subparallel to foliation and [001] axis aligned subparallel to lineation. Type-ABC LPO is defined as both （100） and （010） planes aligned subparallel to foliation with a girdle distribution of both [100] and [010] axes normal to lineation and [001] axis aligned subparallel to lineation. We report for the first time the type-AB, -BC, and -ABC LPO of orthopyroxerie. We found that the LPO pattern has a correlation with the content of orthopyroxene in the specimen. Nicolet 6700 FTIR （Fourier transformation infrared） study of enstatite showed that type-AC LPO was observed mostly in the samples of enstatite with low water content. It is found that the strength of the LPO of enstatite decreases with increasing water content and has a correlation with the strength of the LPO of olivine： the stronger the LPO of enstatite, the stronger the LPO of olivine. Seismic anisotropy of enstatite was smaller than that of olivine in the same specimen.展开更多
Melt-spun （Nd11.4Fe82.9B5.7）0.99M1 ribbons （M = Zr, Nb, Ga, Zr＋ Ga, Nb ＋ Ga）were prepared by melt-spinning technique. Ga addition is found to be effective for the orientation of c-axis of Nd2Fe14B grains perpend...Melt-spun （Nd11.4Fe82.9B5.7）0.99M1 ribbons （M = Zr, Nb, Ga, Zr＋ Ga, Nb ＋ Ga）were prepared by melt-spinning technique. Ga addition is found to be effective for the orientation of c-axis of Nd2Fe14B grains perpendicular to the ribbon plane. Better magnetic properties can be achieved by adding both the two kinds of elements Zr ＋ Ga, Nb ＋ Ga, and it is found that the preferred orientation is further improved. The alignment degree changes with ribbon thickness and is highest when ribbon thickness is 120 μm. Heat treatment can improve the texture degree, but lead to coarser grains. Cryogenic treatment is first applied for the treatment of nanocomposite Nd2Fe14B/α-Fe melt-spun ribbons. The effects on magnetic properties and texture degree of nanocomposite magnets after cryogenic treatment were studied. The result shows that cryogenic treatment is beneficial to the enhancement of texture degree of melt-spun ribbon and the grain size has no obvious change.展开更多
The relationship between crystal growth mode, preferred orientation and magnetostrictive properties of （Tb0.3Dy0.7）Fe1.95 alloys was investigated at different directional solidification rates. The results showed tha...The relationship between crystal growth mode, preferred orientation and magnetostrictive properties of （Tb0.3Dy0.7）Fe1.95 alloys was investigated at different directional solidification rates. The results showed that preferred orientation had a strong influence on the characteristics of （Tb0.3Dy0.7）Fe1.95 alloys. At lower solidification rates, the sample with 〈110〉 preferred orientation showed larger low-field magnetostriction and apparent compressive stress effect. The excessive solidification rate resulted in failure of preferred orientation and a poor magnetostrictive performance. With an increase in solidification rates, the crystal growth modes changed gradually from cellular and primary dendrite morphology to developed dendritic morphology. In addition, domain configurations were observed using magnetic force microscopy, and the change of magnetostrictive properties was interpreted in terms of revealing the domain configurations.展开更多
High density lanthanum hexaboride(LaB_(6))polycrystalline with(100)preferred orientation was prepared by spark plasma sintering(SPS)using LaB_(6) nanocubes as raw materials in this work.Microstructure and thermionic e...High density lanthanum hexaboride(LaB_(6))polycrystalline with(100)preferred orientation was prepared by spark plasma sintering(SPS)using LaB_(6) nanocubes as raw materials in this work.Microstructure and thermionic electron emission property of LaB_(6) polycrystalline were investigated detailedly.The results show that the LaB_(6) polycrystalline had a relative density of 95.8%,and there was a(100)preferred orientation on its surface normal to SPS pressing direction.The work function of LaB_(6) polycrystalline normal surface was only 2.73 eV,which was almost close to the theoretical work function of LaB_(6)(100)single crystal surface.The reasons for preferential orientation of LaB_(6) polycrystalline were analyzed.展开更多
Through an understanding of diffusion,precise control of the size distribution of nano-precipitates can be essential to developing superior properties in precipitation-strengthened alloys.Although a significant influe...Through an understanding of diffusion,precise control of the size distribution of nano-precipitates can be essential to developing superior properties in precipitation-strengthened alloys.Although a significant influence of crystallographic orientation on the diffusion process is known to exist in low-symmetry hexagonal close-packed alloys,such anisotropic diffusion is still unidentified in high-symmetry cubic alloys.In this work,we reveal the diffusion-controlled coarsening induced anisotropic growth process of nano-precipitates in an Al-Zn-Mg-Cu alloy.Our experimental and theoretical studies demonstrate that with an increase in the residual stress,the diffusion-controlled coarsening rate is slow along the<112>fiber texture in the alloy matrix with smaller grain sizes.As such,we find that the diffusion activation energy will be increased along the preferred orientation with largest residual stress,which leads to a reduced diffusion-controlled coarsening rate.Specifically,we demonstrate that the increase in the volume fraction of nano-precipitates originates from the rapid grain-boundary controlled coarsening of the grainboundary precipitates.Based on these results,an underlying microstructural design strategy is proposed,involving the crystallographic orientation,the residual stress and the grain boundaries to manipulate the precipitate size distribution in this class of alloys.展开更多
Nanoparticle-reinforced metal matrix composite coatings have significant potential in mechanical part surface strengthening owing their excellent mechanical properties.This paper reports a phenomenon in which the grai...Nanoparticle-reinforced metal matrix composite coatings have significant potential in mechanical part surface strengthening owing their excellent mechanical properties.This paper reports a phenomenon in which the grain orientation gradually evolves to(220)as the deposition current density increases when preparing nanoparticle-reinforced nickel-based composite coatings through jet electrodeposition(JED).During the preparation of the Ni-SiC composite coatings,the deposition current density increased from 180 A/dm2 to 220 A/dm2,and TC(220)gradually increase from 41.4%to 97.7%.With an increase of TC(220),the self-corrosion potential increases from−0.575 to−0.477 V,the corrosion current density decreases from 9.52μA/cm^2 to 2.76μA/cm^2,the diameter of the corrosion pits that after 10 days of immersion in a 3.5 wt%NaCl solution decreases from 278–944 nm to 153–260 nm,and the adhesion of the coating increases from 24.9 N to 61.6 N.Compared a conventional electrodeposition(CED),the Ni-SiC composite coating using JED has the advantages of a smooth surface morphology,high corrosion resistance,and strong adhesion,which are more obvious with an increase in TC(220).展开更多
Investigation was made of the deposited rate,surface morphology and crystal pre- ferred orientation of the dense TiC coating onto austenitic stainless steel in relation with CH_4/TiCl_4 mole ratio and temperature adop...Investigation was made of the deposited rate,surface morphology and crystal pre- ferred orientation of the dense TiC coating onto austenitic stainless steel in relation with CH_4/TiCl_4 mole ratio and temperature adopted in CVD processing. When the CH_4/TiCl_4 ratio is low or high,the preferred orientation may be(220)or(200),respec- tively,which is mainly dependent on the equilibrium concentration of active C in vapour phase.展开更多
The room temperature tensile properties of cold rolled and annealed Fe 3(Al,Cr,Zr) alloy are similar to those of warm rolled Fe 3Al alloys. The cold rolled Fe 3(Al,Cr,Zr) alloy is also susceptible to test enviro...The room temperature tensile properties of cold rolled and annealed Fe 3(Al,Cr,Zr) alloy are similar to those of warm rolled Fe 3Al alloys. The cold rolled Fe 3(Al,Cr,Zr) alloy is also susceptible to test environments. It has been shown that the ductility in various environments decreases in sequence of oxygen—oil—air—distilled water. The results of X ray diffraction analysis show that (211) preferred orientation of B 2 phase appears in cold rolled Fe 3(Al,Cr,Zr) alloy after recrystallization annealing.展开更多
The electro-oxidation of ethanol on a highly preferred orientation (220) Ni electrode and alower texture degree Ni electrode in 1 mol/L NaoH was investigated with cyclicvoltammetry. The mechanism of ethanol oxidation ...The electro-oxidation of ethanol on a highly preferred orientation (220) Ni electrode and alower texture degree Ni electrode in 1 mol/L NaoH was investigated with cyclicvoltammetry. The mechanism of ethanol oxidation on the highly preferred orientation Nielectrode is proposed. It is shown that the current peak of electro-oxidation of ethanol onthe highly preferred orientation (220) Ni electrode is much higher than that of the lowertextUre degree (220) Ni electrode, Ni(Ⅲ) on the surface of the highly preferredorientation(220)Ni electrode is responsible for the oxidation ethanol.展开更多
Polycrystalline Bi_4Ti_3O_（12） thin films with various fractions of a-axis, c-axis and random orientations have been grown on Pt（111）/Ti/Si O_2/Si substrates by laser-ablation under different kinetic growth condit...Polycrystalline Bi_4Ti_3O_（12） thin films with various fractions of a-axis, c-axis and random orientations have been grown on Pt（111）/Ti/Si O_2/Si substrates by laser-ablation under different kinetic growth conditions. The relationship between the structure and ferroelectric property of the films was investigated, so as to explore the possibility of enhancing ferroelectric polarization by controlling the preferred orientation. The structural characterization indicated that the large growth rate and high oxygen background pressure were both favorable for the growth of non-c-axis oriented grains in the Bi_4Ti_3O_（12） thin films. The films with high fractions of a-axis and random orientations, i e, f（a-sxis） = 28.3% and f（random） = 69.6%, could be obtained at the deposition temperature of 973 K, oxygen partial pressure of 15 Pa and laser fluence of 4.6 J/cm^2, respectively. It was also noted that the variation of ferroelectric polarization was in accordance with the evolution non-c-axis orientation. A large value of remanent polarization（2 Pr = 35.5 μC/cm^2） was obtained for the Bi_4Ti_3O_（12） thin films with significant non-c-axis orientation, even higher than that of rare-earth-doped Bi_4Ti_3O_（12） films.展开更多
In this work, we make an investigation on the preferences of orientations between amino acids using the orientation defined based on the local geometry of the amino acids concerned. It is found that there are common p...In this work, we make an investigation on the preferences of orientations between amino acids using the orientation defined based on the local geometry of the amino acids concerned. It is found that there are common preferences of orientations （70°, 30°, 140°） and （110°, 340°, 100°） for various pairs of amino acids. Different side chains may strengthen or weaken the common preferences, which is related to the effect of packing. Some amino acids having specific local flexibility may possess some preferences of orientations besides the common ones, such as （10°, 280°, 210°）. Another analysis on the pairs of the amino acids with different secondary-structure preferences shows that the directional interaction may affect the distribution of orientation more effectively than the packing or local flexibility. All these results provide us some insight of the organization of amino acids in protein, and their relation with some related interactions.展开更多
This work focuses on the preferable orientation analysis of the hybrid system where the C60 molecules are encap- sulated inside the boron nitride nanotubes by using the two-molecule model. The low-energy state can be ...This work focuses on the preferable orientation analysis of the hybrid system where the C60 molecules are encap- sulated inside the boron nitride nanotubes by using the two-molecule model. The low-energy state can be acquired in the contour map, which provides the visual information of the systematical van der Waals interaction potential for the C60 molecules adopting different orientations. Our results show that the C60 molecules exhibit the pre- ferred pentagon and hexagon orientations with the tube＇s diameter smaller and larger than 13.55A, respectively. The preferred two-bond orientation obtained in the single-molecule model is absent in this study, indicating that the intermolecular interaction of adjacent C60 molecules plays an important role in the orientational behaviors of this peapod structure.展开更多
Aqueous zinc-ion batteries(AZIBs)are facing the challenges of low stability of Zn anodes with dendrite growth and hydrogen evolution reaction in promoting commercial applications.We report herein a dualconfiguration b...Aqueous zinc-ion batteries(AZIBs)are facing the challenges of low stability of Zn anodes with dendrite growth and hydrogen evolution reaction in promoting commercial applications.We report herein a dualconfiguration bifunctional DL-citrulline(DL-Cit)as an electrolyte additive to stabilize Zn anodes for ultralong cycle-life aqueous energy storage.Trace amounts of DL-Cit reconstruct the solvation structure of Zn^(2+)via strong interactions with Zn^(2+),while DL-Cit is preferentially adsorbed on Zn anode surfaces to orchestrate the ion flux and ensure uniform Zn deposition.The well-formed flat Zn(002)texture not only enhances the electrochemical stability of Zn anodes but also exhibits more significant orientation priority upon increasing current density.These properties endow Zn anodes with an average coulombic efficiency of 99.7% after 1500 cycles and a long cycle life of over 3000 h,achieving an ultrahigh cumulative plating capacity of 4.8 Ah cm^(-2)even under rigorous plating/stripping conditions(8 mA cm^(-2)).Consequently,the Zn||MnO_(2)full cells provide a high capacity of 143.35 mA h g-1after continuous cycling for more than3000 cycles.The Zn||activated carbon hybrid capacitors with DL-Cit additives operate stably beyond30,000 cycles.This versatile electrolyte strategy provides an effective solution for the practical application of Zn-based energy storage devices.展开更多
Compared with sintered silicon carbides(SiC),highly-orientated 3C-SiC by CVD methods boast out-of-plane orientation uniformity,which ensures that such materials produce lower surface damage.Through the electrolytic in...Compared with sintered silicon carbides(SiC),highly-orientated 3C-SiC by CVD methods boast out-of-plane orientation uniformity,which ensures that such materials produce lower surface damage.Through the electrolytic in-process dressing(ELID)grinding technique,the differences in grinding behaviors between<110>and<111>-orientated 3C-SiC were investigated.Both highly-orientated 3C-SiC exhibited a grinding surface where brittle and ductile removal coexisted.Specifically,brittle removal regions were observed at grain boundaries,while ductile removal regions were observed within the grains.Further indentation experiments between the two 3C-SiC show that<111>-oriented 3C-SiC displays a larger critical cut depth of 28.99 nm,with 1.5 times higher than that of<110>-oriented 3C-SiC.The larger critical depth of cut contributes to more ductile removal regions with only a few brittle pits in the<111>-oriented 3C-SiC grinding surface.In addition,the subsurface deformation of<110>-oriented 3C-SiC was characterized by the presence of amorphous zones,dislocations and stacking faults.In contrast to the<111>-oriented,the<110>-oriented 3C-SiC tends to exhibit a brittle removal mode dominated by pits and cracks at the twin boundaries,as its pre-existing twins hinder the dislocation glide,resulting in stress concentration and thus forming cracks.展开更多
基金supported by the Korea Meteorological Ad-ministration Research and Development Program (No. CATER 2008-5112)
文摘Lattice preferred orientation （LPO） and seismic anisotropy of orthopyroxene （enstatite） in mantle xenoliths from Spitsbergen, Svalbard, near the Arctic, are studied. LPOs of enstatite were determined using electron backseattered diffraction （EBSD）. We found four types of LPOs of orthopyroxene and defined them as type-AC, -AB, -BC, and -ABC. Type-AC LPO of orthopyroxene is defined as （100） plane aligned subparallel to foliation and [001] axis aligned subparallel to lineation. Type-AB LPO is defined as （100） plane aligned subparallel to foliation and [010] axis aligned subparallel to linea- tion. Type-BC LPO is defined as （010） plane aligned subparallel to foliation and [001] axis aligned subparallel to lineation. Type-ABC LPO is defined as both （100） and （010） planes aligned subparallel to foliation with a girdle distribution of both [100] and [010] axes normal to lineation and [001] axis aligned subparallel to lineation. We report for the first time the type-AB, -BC, and -ABC LPO of orthopyroxerie. We found that the LPO pattern has a correlation with the content of orthopyroxene in the specimen. Nicolet 6700 FTIR （Fourier transformation infrared） study of enstatite showed that type-AC LPO was observed mostly in the samples of enstatite with low water content. It is found that the strength of the LPO of enstatite decreases with increasing water content and has a correlation with the strength of the LPO of olivine： the stronger the LPO of enstatite, the stronger the LPO of olivine. Seismic anisotropy of enstatite was smaller than that of olivine in the same specimen.
文摘Melt-spun （Nd11.4Fe82.9B5.7）0.99M1 ribbons （M = Zr, Nb, Ga, Zr＋ Ga, Nb ＋ Ga）were prepared by melt-spinning technique. Ga addition is found to be effective for the orientation of c-axis of Nd2Fe14B grains perpendicular to the ribbon plane. Better magnetic properties can be achieved by adding both the two kinds of elements Zr ＋ Ga, Nb ＋ Ga, and it is found that the preferred orientation is further improved. The alignment degree changes with ribbon thickness and is highest when ribbon thickness is 120 μm. Heat treatment can improve the texture degree, but lead to coarser grains. Cryogenic treatment is first applied for the treatment of nanocomposite Nd2Fe14B/α-Fe melt-spun ribbons. The effects on magnetic properties and texture degree of nanocomposite magnets after cryogenic treatment were studied. The result shows that cryogenic treatment is beneficial to the enhancement of texture degree of melt-spun ribbon and the grain size has no obvious change.
基金National High-Tech R&D Program(2006AA03Z106)Beijing Natural Science Foundation (2062012)
文摘The relationship between crystal growth mode, preferred orientation and magnetostrictive properties of （Tb0.3Dy0.7）Fe1.95 alloys was investigated at different directional solidification rates. The results showed that preferred orientation had a strong influence on the characteristics of （Tb0.3Dy0.7）Fe1.95 alloys. At lower solidification rates, the sample with 〈110〉 preferred orientation showed larger low-field magnetostriction and apparent compressive stress effect. The excessive solidification rate resulted in failure of preferred orientation and a poor magnetostrictive performance. With an increase in solidification rates, the crystal growth modes changed gradually from cellular and primary dendrite morphology to developed dendritic morphology. In addition, domain configurations were observed using magnetic force microscopy, and the change of magnetostrictive properties was interpreted in terms of revealing the domain configurations.
基金Project(51902342)supported by the National Natural Science Foundation of China。
文摘High density lanthanum hexaboride(LaB_(6))polycrystalline with(100)preferred orientation was prepared by spark plasma sintering(SPS)using LaB_(6) nanocubes as raw materials in this work.Microstructure and thermionic electron emission property of LaB_(6) polycrystalline were investigated detailedly.The results show that the LaB_(6) polycrystalline had a relative density of 95.8%,and there was a(100)preferred orientation on its surface normal to SPS pressing direction.The work function of LaB_(6) polycrystalline normal surface was only 2.73 eV,which was almost close to the theoretical work function of LaB_(6)(100)single crystal surface.The reasons for preferential orientation of LaB_(6) polycrystalline were analyzed.
基金supported by the National Key Research and Development Program of China(No.2017YFF0210002)the National Science and Technology Major Projects of China(No.J2019VII-0015-0155).
文摘Through an understanding of diffusion,precise control of the size distribution of nano-precipitates can be essential to developing superior properties in precipitation-strengthened alloys.Although a significant influence of crystallographic orientation on the diffusion process is known to exist in low-symmetry hexagonal close-packed alloys,such anisotropic diffusion is still unidentified in high-symmetry cubic alloys.In this work,we reveal the diffusion-controlled coarsening induced anisotropic growth process of nano-precipitates in an Al-Zn-Mg-Cu alloy.Our experimental and theoretical studies demonstrate that with an increase in the residual stress,the diffusion-controlled coarsening rate is slow along the<112>fiber texture in the alloy matrix with smaller grain sizes.As such,we find that the diffusion activation energy will be increased along the preferred orientation with largest residual stress,which leads to a reduced diffusion-controlled coarsening rate.Specifically,we demonstrate that the increase in the volume fraction of nano-precipitates originates from the rapid grain-boundary controlled coarsening of the grainboundary precipitates.Based on these results,an underlying microstructural design strategy is proposed,involving the crystallographic orientation,the residual stress and the grain boundaries to manipulate the precipitate size distribution in this class of alloys.
基金Supported by National Natural Science Foundation of China(Grant No.51675535)Major Research Project of Shandong Province of China(Grant No.2019GGX104068)+3 种基金Key Pre-Research Foundation of Military Equipment of China(Grant No.6140923030702)National Science and Technology Major Project of China(Grant No.2017ZX05072)Graduate Innovation Protect of China University of Petroleum(East China)(Grant No.YCX2020059)Science and Technology Support Plan for Youth Innovation of Universities in Shandong Province of China(Grant No.2019KJB016).
文摘Nanoparticle-reinforced metal matrix composite coatings have significant potential in mechanical part surface strengthening owing their excellent mechanical properties.This paper reports a phenomenon in which the grain orientation gradually evolves to(220)as the deposition current density increases when preparing nanoparticle-reinforced nickel-based composite coatings through jet electrodeposition(JED).During the preparation of the Ni-SiC composite coatings,the deposition current density increased from 180 A/dm2 to 220 A/dm2,and TC(220)gradually increase from 41.4%to 97.7%.With an increase of TC(220),the self-corrosion potential increases from−0.575 to−0.477 V,the corrosion current density decreases from 9.52μA/cm^2 to 2.76μA/cm^2,the diameter of the corrosion pits that after 10 days of immersion in a 3.5 wt%NaCl solution decreases from 278–944 nm to 153–260 nm,and the adhesion of the coating increases from 24.9 N to 61.6 N.Compared a conventional electrodeposition(CED),the Ni-SiC composite coating using JED has the advantages of a smooth surface morphology,high corrosion resistance,and strong adhesion,which are more obvious with an increase in TC(220).
文摘Investigation was made of the deposited rate,surface morphology and crystal pre- ferred orientation of the dense TiC coating onto austenitic stainless steel in relation with CH_4/TiCl_4 mole ratio and temperature adopted in CVD processing. When the CH_4/TiCl_4 ratio is low or high,the preferred orientation may be(220)or(200),respec- tively,which is mainly dependent on the equilibrium concentration of active C in vapour phase.
文摘The room temperature tensile properties of cold rolled and annealed Fe 3(Al,Cr,Zr) alloy are similar to those of warm rolled Fe 3Al alloys. The cold rolled Fe 3(Al,Cr,Zr) alloy is also susceptible to test environments. It has been shown that the ductility in various environments decreases in sequence of oxygen—oil—air—distilled water. The results of X ray diffraction analysis show that (211) preferred orientation of B 2 phase appears in cold rolled Fe 3(Al,Cr,Zr) alloy after recrystallization annealing.
文摘The electro-oxidation of ethanol on a highly preferred orientation (220) Ni electrode and alower texture degree Ni electrode in 1 mol/L NaoH was investigated with cyclicvoltammetry. The mechanism of ethanol oxidation on the highly preferred orientation Nielectrode is proposed. It is shown that the current peak of electro-oxidation of ethanol onthe highly preferred orientation (220) Ni electrode is much higher than that of the lowertextUre degree (220) Ni electrode, Ni(Ⅲ) on the surface of the highly preferredorientation(220)Ni electrode is responsible for the oxidation ethanol.
基金Funded by the International Science and Technology Cooperation Project of Hubei Province(2016AHB008)the Natural Science Foundation of Hubei Province(2015CFB724,2016CFA006)+1 种基金the National Natural Science Foundation of China(51272195,51521001)the National Key Research and Development Program of China(2017YFB0310400)
文摘Polycrystalline Bi_4Ti_3O_（12） thin films with various fractions of a-axis, c-axis and random orientations have been grown on Pt（111）/Ti/Si O_2/Si substrates by laser-ablation under different kinetic growth conditions. The relationship between the structure and ferroelectric property of the films was investigated, so as to explore the possibility of enhancing ferroelectric polarization by controlling the preferred orientation. The structural characterization indicated that the large growth rate and high oxygen background pressure were both favorable for the growth of non-c-axis oriented grains in the Bi_4Ti_3O_（12） thin films. The films with high fractions of a-axis and random orientations, i e, f（a-sxis） = 28.3% and f（random） = 69.6%, could be obtained at the deposition temperature of 973 K, oxygen partial pressure of 15 Pa and laser fluence of 4.6 J/cm^2, respectively. It was also noted that the variation of ferroelectric polarization was in accordance with the evolution non-c-axis orientation. A large value of remanent polarization（2 Pr = 35.5 μC/cm^2） was obtained for the Bi_4Ti_3O_（12） thin films with significant non-c-axis orientation, even higher than that of rare-earth-doped Bi_4Ti_3O_（12） films.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10204013, 90103031, 10074030, 10474041, 90403120 and 10021001）, and the Nonlinear Project （973） of the National Science Ministry, China.
文摘In this work, we make an investigation on the preferences of orientations between amino acids using the orientation defined based on the local geometry of the amino acids concerned. It is found that there are common preferences of orientations （70°, 30°, 140°） and （110°, 340°, 100°） for various pairs of amino acids. Different side chains may strengthen or weaken the common preferences, which is related to the effect of packing. Some amino acids having specific local flexibility may possess some preferences of orientations besides the common ones, such as （10°, 280°, 210°）. Another analysis on the pairs of the amino acids with different secondary-structure preferences shows that the directional interaction may affect the distribution of orientation more effectively than the packing or local flexibility. All these results provide us some insight of the organization of amino acids in protein, and their relation with some related interactions.
基金Supported by the National Basic Research Program of China under Grant No 2011CB808200the National Natural Science Foundation of China under Grant Nos 11504150,11304020 and 51320105007the Cheung Kong Scholars Programme of China
文摘This work focuses on the preferable orientation analysis of the hybrid system where the C60 molecules are encap- sulated inside the boron nitride nanotubes by using the two-molecule model. The low-energy state can be acquired in the contour map, which provides the visual information of the systematical van der Waals interaction potential for the C60 molecules adopting different orientations. Our results show that the C60 molecules exhibit the pre- ferred pentagon and hexagon orientations with the tube＇s diameter smaller and larger than 13.55A, respectively. The preferred two-bond orientation obtained in the single-molecule model is absent in this study, indicating that the intermolecular interaction of adjacent C60 molecules plays an important role in the orientational behaviors of this peapod structure.
基金financially supported by the National Natural Science Foundation of China(22375170,21875111)the Tan Kah Kee Innovation Laboratory(HRTP-[2022]-45)the Plans for the Recruitment of Top-notch Talent by Fujian Province and Xiamen City。
文摘Aqueous zinc-ion batteries(AZIBs)are facing the challenges of low stability of Zn anodes with dendrite growth and hydrogen evolution reaction in promoting commercial applications.We report herein a dualconfiguration bifunctional DL-citrulline(DL-Cit)as an electrolyte additive to stabilize Zn anodes for ultralong cycle-life aqueous energy storage.Trace amounts of DL-Cit reconstruct the solvation structure of Zn^(2+)via strong interactions with Zn^(2+),while DL-Cit is preferentially adsorbed on Zn anode surfaces to orchestrate the ion flux and ensure uniform Zn deposition.The well-formed flat Zn(002)texture not only enhances the electrochemical stability of Zn anodes but also exhibits more significant orientation priority upon increasing current density.These properties endow Zn anodes with an average coulombic efficiency of 99.7% after 1500 cycles and a long cycle life of over 3000 h,achieving an ultrahigh cumulative plating capacity of 4.8 Ah cm^(-2)even under rigorous plating/stripping conditions(8 mA cm^(-2)).Consequently,the Zn||MnO_(2)full cells provide a high capacity of 143.35 mA h g-1after continuous cycling for more than3000 cycles.The Zn||activated carbon hybrid capacitors with DL-Cit additives operate stably beyond30,000 cycles.This versatile electrolyte strategy provides an effective solution for the practical application of Zn-based energy storage devices.
基金the Central Guidance on Local Science and Technology Development Fund of Hubei Province(No.2022BFE002)the Independent Innovation Projects of the Hubei Longzhong Laboratory(No.2022ZZ-06)the National Natural Science Foundation of China(Nos.52002075 and 62204179)。
文摘Compared with sintered silicon carbides(SiC),highly-orientated 3C-SiC by CVD methods boast out-of-plane orientation uniformity,which ensures that such materials produce lower surface damage.Through the electrolytic in-process dressing(ELID)grinding technique,the differences in grinding behaviors between<110>and<111>-orientated 3C-SiC were investigated.Both highly-orientated 3C-SiC exhibited a grinding surface where brittle and ductile removal coexisted.Specifically,brittle removal regions were observed at grain boundaries,while ductile removal regions were observed within the grains.Further indentation experiments between the two 3C-SiC show that<111>-oriented 3C-SiC displays a larger critical cut depth of 28.99 nm,with 1.5 times higher than that of<110>-oriented 3C-SiC.The larger critical depth of cut contributes to more ductile removal regions with only a few brittle pits in the<111>-oriented 3C-SiC grinding surface.In addition,the subsurface deformation of<110>-oriented 3C-SiC was characterized by the presence of amorphous zones,dislocations and stacking faults.In contrast to the<111>-oriented,the<110>-oriented 3C-SiC tends to exhibit a brittle removal mode dominated by pits and cracks at the twin boundaries,as its pre-existing twins hinder the dislocation glide,resulting in stress concentration and thus forming cracks.
