In this paper we give a new and elementary proof to the following fact:each closed orientable surface of positive genus admits a both chaotic and expansive homeomorphism.Further more,we show that the homeomorphisms gi...In this paper we give a new and elementary proof to the following fact:each closed orientable surface of positive genus admits a both chaotic and expansive homeomorphism.Further more,we show that the homeomorphisms given are also weakly mixing.展开更多
In this paper, we discuss the crossing numbers of two one-vertex maps on orientable surfaces. By using a reductive method, we give the crossing number of two one-vertex maps with one face on an orientable surface and ...In this paper, we discuss the crossing numbers of two one-vertex maps on orientable surfaces. By using a reductive method, we give the crossing number of two one-vertex maps with one face on an orientable surface and the crossing number of a one-vertex map with one face and a one-vertex map with two faces on an orientable surface. This provides a lower bound for the crossing number of two general maps on an orientable surface.展开更多
Interaction of straight chain alcohol vapors with MOF-199-functionalized films was studied by SPR. The signals had linear relationships with the concentration of alcohols over a wide range from 0 to 70% （v/v） and we...Interaction of straight chain alcohol vapors with MOF-199-functionalized films was studied by SPR. The signals had linear relationships with the concentration of alcohols over a wide range from 0 to 70% （v/v） and were reversible in proportional to the chain length, with R2 all above 0.99.展开更多
The performance of double gate GaSb nMOSFETs with surface orientations of（100） and（111） are compared by deterministically solving the time-dependent Boltzmann transport equation（BTE）.Results show that the on-sta...The performance of double gate GaSb nMOSFETs with surface orientations of（100） and（111） are compared by deterministically solving the time-dependent Boltzmann transport equation（BTE）.Results show that the on-state current of the device with（111） surface orientation is almost three times larger than the（100） case due to the higher injection velocity.Moreover,the scattering rate of the（111） device is slightly lower than that of the（100） device.展开更多
The influence of the magnetism of transition metal oxide,nickel(II)oxide(NiO),on its surface reactivity and the dependence of surface reactivity on surface orientation and reactant magnetism were studied by density fu...The influence of the magnetism of transition metal oxide,nickel(II)oxide(NiO),on its surface reactivity and the dependence of surface reactivity on surface orientation and reactant magnetism were studied by density functional theory plus U calculations.We considered five different antiferromagnetically ordered structures and one ferromagnetically ordered structure,NiO(001)and Ni(011)surfaces,paramagnetic molecule NO,and nonparamagnetic molecule CO.The calculations showed that the dependence of surface energies on magnetism was modest,ranging from49to54meV/?2for NiO(001)and from162to172meV/?2for NiO(011).On NiO(001),both molecules preferred the top site of the Ni cation exclusively for all NiO magnetic structures considered,and calculated adsorption energies ranged from?0.33to?0.37eV for CO and from?0.42to?0.46eV for NO.On NiO(011),both molecules preferred the bridge site of two Ni cations irrespective of the NiO magnetism.It was found that rather than the long‐range magnetism of bulk NiO,the local magnetic order of two coordinated Ni cations binding to the adsorbed molecule had a pronounced influence on adsorption.The calculated NO adsorption energy at the(↑↓)bridge sites ranged from?0.99to?1.05eV,and become stronger at the(↑↑)bridge sites with values of?1.21to?1.30eV.For CO,although the calculated adsorption energies at the(↑↓)bridge sites(?0.73to?0.75eV)were very close to those at the(↑↑)bridge sites(?0.71to?0.72eV),their electron hybridizations were very different.The present work highlights the importance of the local magnetic order of transition metal oxides on molecular adsorption at multi‐fold sites.展开更多
For reducing the core loss of grain oriented silicon steel and improving its aging property, a new method, the LLSA by using Sb as the laser surface alloying element, was investigated, and at proper technique conditio...For reducing the core loss of grain oriented silicon steel and improving its aging property, a new method, the LLSA by using Sb as the laser surface alloying element, was investigated, and at proper technique conditions rather good result was obtained.展开更多
The precipitation of epsilon copper at 1023 K ageing in ferrite antibacterial stainless steel was investigated by a combination of electron microscopy and micro-Vickers hardness measurement. The results show that epsi...The precipitation of epsilon copper at 1023 K ageing in ferrite antibacterial stainless steel was investigated by a combination of electron microscopy and micro-Vickers hardness measurement. The results show that epsilon copper precipitation occurs within 90 s, Complex multilayer structure confirmed as twins and stacking faults on {111}ε-Cu planes was observed in the precipitates. The precipitates grow by the lengthwise enlargement of a set of parallel layers, having [111]ε-Cu and [112]ε-Cu preferred growth orientations. The volume fraction of precipitates f formed within 120 min can be predicted by a modified Avrami equation （In1/1-f= kt ＋ b）. Simultaneously, substituent atom clusters with a size of 5-10 nm was found to occur in the solution and cause matrix strain. The precipitate morphology and distribution on the surface of ferrite antibacterial stainless steel are associated with surface crystallographic orientation of the matrix. The precipitates are predominantly located within the ferrite grains of 〈110〉 orientation. The precipitates located on {111}α-Fe surface planes have sphere or ellipse shape.展开更多
The salt effects on molecular orientation at air/liquid methanol interface were investigated by the polarization-dependent sum frequency generation vibrational spectroscopy（SFG-VS）. We clarified that the average til...The salt effects on molecular orientation at air/liquid methanol interface were investigated by the polarization-dependent sum frequency generation vibrational spectroscopy（SFG-VS）. We clarified that the average tilting angle of the methyl group to be u = 308 58 at the air/pure methanol surface assuming a d-function orientational distribution. Upon the addition of 3 mol/L Na I, the methyl group tilts further away from the surface normal with a new u = 418 38. This orientational change does not explain the enhancement of the SFG-VS intensities when adding Na I, implying the number density of the methanol molecules with a net polar ordering in the surface region also changed with the Na I concentrations. These spectroscopic findings shed new light on the salt effects on the surfaces structures of the polar organic solutions. It was also shown that the accurate determination of the bulk refractive indices and Raman depolarization ratios for different salt concentrations is crucial to quantitatively interpret the SFG-VS data.展开更多
This study employs the kinetics framework of Marcus-Hush-Chidsey(MHC)to investigate the charge transfer at the interface of lithium electrode and electrolyte in lithium(ion)-batteries.The chargetransfer rate constant ...This study employs the kinetics framework of Marcus-Hush-Chidsey(MHC)to investigate the charge transfer at the interface of lithium electrode and electrolyte in lithium(ion)-batteries.The chargetransfer rate constant is evaluated for different facets of lithium,namely(100),(110),(101),and(111)as a function of surface charge density with the aid of density functional theory(DFT)calculations.The results highlight and quantify the sensitivity of the rate of lithium plating and stripping to the surface orientation,surface charge density,and charge-transfer over-potential.An intrinsic kinetics competition among the different surface orientations is identified together with an asymmetry between the lithium plating and stripping and showcased to influence the deposit morphology and surface protrusions and indentations.展开更多
Work function plays a significant role in surface chemistry. Local work function provides the information of local d/pole-d/pole interaction and charge distribution between adsorbates and substrate, highlighting the l...Work function plays a significant role in surface chemistry. Local work function provides the information of local d/pole-d/pole interaction and charge distribution between adsorbates and substrate, highlighting the local charge effect of the targeted spot which is normally smeared out in conventional average work function measurements. Chloroaluminum phthalocyanine （CIA1Pc）, an important optoelectronic molecule with a permanent dipole moment pointing from the Pc ring to the ending CI atom, adsorbed on Au（111） in either Cl-up or Cl-down configuration. Scanning tunneling microscopy/spectroscopy measurements revealed that at the centers of Cl-up and CI-down molecules, the local work functions changed oppositely with respect to the Au（111） substrate. At their Pc lobes, however, the local work functions unanimously increased due to charging effect of the indole lobes in the CIAIPc molecule.展开更多
The embedding technique based on an operator appeared in [Liu, Y. P., Scientia Sinica, Special Issue on Math,1 (1979),191-201 (in Chinese)] for determining the maximum non-orientable genus of a graph is developed to o...The embedding technique based on an operator appeared in [Liu, Y. P., Scientia Sinica, Special Issue on Math,1 (1979),191-201 (in Chinese)] for determining the maximum non-orientable genus of a graph is developed to obtain the general theorem which presents a necessary and sufficient condition for a graph to be embeddable into either the orientable or the non-orientable surface of genus k. Furthermore,the greatest lower bound of the lengths of genus ranges of the class of nonplanar graphs which are up-embeddable is also obtained.展开更多
A near-triangular embedding is an embedded graph into some surface whose all but one facial walks are 3-gons. In this paper we show that if a graph G is a triangulation of an orientable surface Sh, then G has a near-t...A near-triangular embedding is an embedded graph into some surface whose all but one facial walks are 3-gons. In this paper we show that if a graph G is a triangulation of an orientable surface Sh, then G has a near-triangular embedding into Sk for k=h, h＋1,...1,[β（G）/2], where β（G） is the Betti number of G.展开更多
基金The first author is supported by the Special Foundation of National Prior Basis Research of China(Grant No.G1999075108)the second author is supported by National Natural Science Foundation of China(11171320 and 11431012).
文摘In this paper we give a new and elementary proof to the following fact:each closed orientable surface of positive genus admits a both chaotic and expansive homeomorphism.Further more,we show that the homeomorphisms given are also weakly mixing.
基金Supported by the National Natural Science Foundation of China (Grant No.10671073)Science and Technology Commission of Shanghai Municipality (Grant No.07XD14011)
文摘In this paper, we discuss the crossing numbers of two one-vertex maps on orientable surfaces. By using a reductive method, we give the crossing number of two one-vertex maps with one face on an orientable surface and the crossing number of a one-vertex map with one face and a one-vertex map with two faces on an orientable surface. This provides a lower bound for the crossing number of two general maps on an orientable surface.
基金supported by NSFC(Nos.21027003, 21235007 and 91117010)Ministry of Science and Technology(No. 2012IM030400) and Chinese Academy of Sciences
文摘Interaction of straight chain alcohol vapors with MOF-199-functionalized films was studied by SPR. The signals had linear relationships with the concentration of alcohols over a wide range from 0 to 70% （v/v） and were reversible in proportional to the chain length, with R2 all above 0.99.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61674008,61421005,and 61404005)
文摘The performance of double gate GaSb nMOSFETs with surface orientations of（100） and（111） are compared by deterministically solving the time-dependent Boltzmann transport equation（BTE）.Results show that the on-state current of the device with（111） surface orientation is almost three times larger than the（100） case due to the higher injection velocity.Moreover,the scattering rate of the（111） device is slightly lower than that of the（100） device.
基金supported by the National Natural Science Foundation of China(91645202)the National Key R&D Program of China(2017YFB602205)+1 种基金the National Basic Research Program of China(2013CB834603)the Frontier Science Key Project of Chinese Academy of Sciences(QYZDJ-SSW-SLH054)~~
文摘The influence of the magnetism of transition metal oxide,nickel(II)oxide(NiO),on its surface reactivity and the dependence of surface reactivity on surface orientation and reactant magnetism were studied by density functional theory plus U calculations.We considered five different antiferromagnetically ordered structures and one ferromagnetically ordered structure,NiO(001)and Ni(011)surfaces,paramagnetic molecule NO,and nonparamagnetic molecule CO.The calculations showed that the dependence of surface energies on magnetism was modest,ranging from49to54meV/?2for NiO(001)and from162to172meV/?2for NiO(011).On NiO(001),both molecules preferred the top site of the Ni cation exclusively for all NiO magnetic structures considered,and calculated adsorption energies ranged from?0.33to?0.37eV for CO and from?0.42to?0.46eV for NO.On NiO(011),both molecules preferred the bridge site of two Ni cations irrespective of the NiO magnetism.It was found that rather than the long‐range magnetism of bulk NiO,the local magnetic order of two coordinated Ni cations binding to the adsorbed molecule had a pronounced influence on adsorption.The calculated NO adsorption energy at the(↑↓)bridge sites ranged from?0.99to?1.05eV,and become stronger at the(↑↑)bridge sites with values of?1.21to?1.30eV.For CO,although the calculated adsorption energies at the(↑↓)bridge sites(?0.73to?0.75eV)were very close to those at the(↑↑)bridge sites(?0.71to?0.72eV),their electron hybridizations were very different.The present work highlights the importance of the local magnetic order of transition metal oxides on molecular adsorption at multi‐fold sites.
基金National Natural Science FOundation of China! (No. 59974010).
文摘For reducing the core loss of grain oriented silicon steel and improving its aging property, a new method, the LLSA by using Sb as the laser surface alloying element, was investigated, and at proper technique conditions rather good result was obtained.
文摘The precipitation of epsilon copper at 1023 K ageing in ferrite antibacterial stainless steel was investigated by a combination of electron microscopy and micro-Vickers hardness measurement. The results show that epsilon copper precipitation occurs within 90 s, Complex multilayer structure confirmed as twins and stacking faults on {111}ε-Cu planes was observed in the precipitates. The precipitates grow by the lengthwise enlargement of a set of parallel layers, having [111]ε-Cu and [112]ε-Cu preferred growth orientations. The volume fraction of precipitates f formed within 120 min can be predicted by a modified Avrami equation （In1/1-f= kt ＋ b）. Simultaneously, substituent atom clusters with a size of 5-10 nm was found to occur in the solution and cause matrix strain. The precipitate morphology and distribution on the surface of ferrite antibacterial stainless steel are associated with surface crystallographic orientation of the matrix. The precipitates are predominantly located within the ferrite grains of 〈110〉 orientation. The precipitates located on {111}α-Fe surface planes have sphere or ellipse shape.
基金supported by the National Natural Science Foundation of China (Nos. 21227802, 21303216 and 21473217)
文摘The salt effects on molecular orientation at air/liquid methanol interface were investigated by the polarization-dependent sum frequency generation vibrational spectroscopy（SFG-VS）. We clarified that the average tilting angle of the methyl group to be u = 308 58 at the air/pure methanol surface assuming a d-function orientational distribution. Upon the addition of 3 mol/L Na I, the methyl group tilts further away from the surface normal with a new u = 418 38. This orientational change does not explain the enhancement of the SFG-VS intensities when adding Na I, implying the number density of the methanol molecules with a net polar ordering in the surface region also changed with the Na I concentrations. These spectroscopic findings shed new light on the salt effects on the surfaces structures of the polar organic solutions. It was also shown that the accurate determination of the bulk refractive indices and Raman depolarization ratios for different salt concentrations is crucial to quantitatively interpret the SFG-VS data.
基金supported by the European Union’s Horizon 2020 Research and Innovation Program for the Solidify Project(875557)。
文摘This study employs the kinetics framework of Marcus-Hush-Chidsey(MHC)to investigate the charge transfer at the interface of lithium electrode and electrolyte in lithium(ion)-batteries.The chargetransfer rate constant is evaluated for different facets of lithium,namely(100),(110),(101),and(111)as a function of surface charge density with the aid of density functional theory(DFT)calculations.The results highlight and quantify the sensitivity of the rate of lithium plating and stripping to the surface orientation,surface charge density,and charge-transfer over-potential.An intrinsic kinetics competition among the different surface orientations is identified together with an asymmetry between the lithium plating and stripping and showcased to influence the deposit morphology and surface protrusions and indentations.
基金supported by National Natural Science Foundation of China(Nos. 91527303, 21333001,21373020, 61321001)MOST(Nos.2013CB933404,2014CB239302),China
文摘Work function plays a significant role in surface chemistry. Local work function provides the information of local d/pole-d/pole interaction and charge distribution between adsorbates and substrate, highlighting the local charge effect of the targeted spot which is normally smeared out in conventional average work function measurements. Chloroaluminum phthalocyanine （CIA1Pc）, an important optoelectronic molecule with a permanent dipole moment pointing from the Pc ring to the ending CI atom, adsorbed on Au（111） in either Cl-up or Cl-down configuration. Scanning tunneling microscopy/spectroscopy measurements revealed that at the centers of Cl-up and CI-down molecules, the local work functions changed oppositely with respect to the Au（111） substrate. At their Pc lobes, however, the local work functions unanimously increased due to charging effect of the indole lobes in the CIAIPc molecule.
文摘The embedding technique based on an operator appeared in [Liu, Y. P., Scientia Sinica, Special Issue on Math,1 (1979),191-201 (in Chinese)] for determining the maximum non-orientable genus of a graph is developed to obtain the general theorem which presents a necessary and sufficient condition for a graph to be embeddable into either the orientable or the non-orientable surface of genus k. Furthermore,the greatest lower bound of the lengths of genus ranges of the class of nonplanar graphs which are up-embeddable is also obtained.
基金the National Natural Science Foundation of China (19831080)Shanghai City Fundation of Selected Academic Research (04JC14031)
文摘A near-triangular embedding is an embedded graph into some surface whose all but one facial walks are 3-gons. In this paper we show that if a graph G is a triangulation of an orientable surface Sh, then G has a near-triangular embedding into Sk for k=h, h＋1,...1,[β（G）/2], where β（G） is the Betti number of G.
