Four phenoxysilicon networks for nonlinear optical (NLO) applications were designed and prepared by an extended sol-gel process without additional H2O and catalyst. All poled polymer network films possess high second-...Four phenoxysilicon networks for nonlinear optical (NLO) applications were designed and prepared by an extended sol-gel process without additional H2O and catalyst. All poled polymer network films possess high second-order nonlinear optical coefficients (d(33)) Of 10(-7)similar to 10(-8) esu. The investigation of NLO temporal stability at room temperature and elevated temperature (120 degreesC) indicated that these films exhibit high d(33) stability because the orientation of the chromophores are locked in the phenoxysilicon organic/inorganic networks.展开更多
By the generalized Riccati transformation and the integral averaging technique, some sufficient conditions of oscillation of the solutions for second order nonlinear differential equations with damping were discussed....By the generalized Riccati transformation and the integral averaging technique, some sufficient conditions of oscillation of the solutions for second order nonlinear differential equations with damping were discussed.Some sufficient oscillation criteria for previous equations were built up.Some oscillation criteria have been expanded and strengthened in some other known results.展开更多
On the basis of ZINDO method and according to the sum over states(SOS) expression, the program is devised for the calculation of nonlinear second order optical susceptibilites β ijk and studying how ...On the basis of ZINDO method and according to the sum over states(SOS) expression, the program is devised for the calculation of nonlinear second order optical susceptibilites β ijk and studying how different substituents on the phenyl ring attached to the atom silicon influence on the nonlinear second order optical properties of substituted silane series of molecules. The properties of (CH 3) 3Si? ?has been studied particularly. The effect of the length of silica chains on the calculated values has been studied too. The regularity summarized from the calculated results has been explained micromechanically.展开更多
Films were prepared from mixtures of copolymers of 4-nitro-4'-[N-methylacryloyloxyethyl, N'-ethyl] amino azobenzene with glycidyl methacrylate (chromophore content: 6 mol%) and copolymers containing anhydride ...Films were prepared from mixtures of copolymers of 4-nitro-4'-[N-methylacryloyloxyethyl, N'-ethyl] amino azobenzene with glycidyl methacrylate (chromophore content: 6 mol%) and copolymers containing anhydride units, which was obtained by the reaction of 4-nitro-4'-[N-hydroxyethyl, N'-ethyl] amino azobenzene with polymethacryloyl chloride (chromophore content: 25 mol %). During thermal poling process the anhydride reacts with the epoxy group and the resulting crosslinked network structure will stabilize the second harmonic generation in the poled film. The second harmonic generation of the poled film shows a maximum with the variation of composition this is presumed to be due to the effects of the increasing of concentration, orientation order as well as orientation stability of chromophore groups during crosslinking.展开更多
Second order nonlinear optical active 2,3-dichloro-5,6-dicyanopyrazine (DCDCP) and its monoamine-substituted derivatives had been synthesized. Their facile synthesis, high melt point, high incidence af substantial SHG...Second order nonlinear optical active 2,3-dichloro-5,6-dicyanopyrazine (DCDCP) and its monoamine-substituted derivatives had been synthesized. Their facile synthesis, high melt point, high incidence af substantial SHG activity and increased transparency inthe blue and near infrared make this class compounds appealling for further investigation.展开更多
Several oscillation criteria are given for the second order nonlinear differential equation with damped term of the form [α(t)(y'(t))σ]' +p(t)(y'(t))σ+ q(t)f(y(t)) = 0, where α∈C(R, (0,∞)), p(t) and ...Several oscillation criteria are given for the second order nonlinear differential equation with damped term of the form [α(t)(y'(t))σ]' +p(t)(y'(t))σ+ q(t)f(y(t)) = 0, where α∈C(R, (0,∞)), p(t) and q(t) are allowed to change sign on [t0, ∞), and f∈C1 (R, R) such that xf(x) > 0 for x ≠0. Our results improve and extend some known oscillation criteria. Examples are inserted to illustrate our results.展开更多
Some new oscillation theorems are established for the second order nonlinear differential equations with damping of the form where p（t） and q（t） are allowed to change sign on [t0,∞).
Temperature-induced phase transitions offer a promising route to engineer nonlinear optical materials,particularly for infrared applications where conventional design approaches face fundamental limitations.Herein,a t...Temperature-induced phase transitions offer a promising route to engineer nonlinear optical materials,particularly for infrared applications where conventional design approaches face fundamental limitations.Herein,a temperature-induced centrosymmetric(CS)to noncentrosymmetric(NCS)irreversible phase transition strategy was employed to successfully prepare a novel NCS diamond-like(DL)chalcogenide,β-Ag_(4)P_(2)S_(7),which was derived from the CS phaseα-Ag_(4)P_(2)S_(7) transformation.Structural analysis reveals that this transformation involves a reorganization of[Ag_(2)PS_(4)]^(2-)layers from an AA’AA’to AA’A’’AA’A’’stacking pattern,facilitated by bridging[Ag1S_(4)]^(7-)tetrahedra.β-Ag_(4)P_(2)S_(7) has exceptional IR NLO properties,including a strong phase-matchable second-harmonic generation(SHG)response(1.02×AgGaS2)and a wide band gap of 2.90 eV(the largest one in ternary Ag-based DL chalcogenides),which balances excellent NLO response with a wide band gap.Further structure–property relationship analyses show that superior NLO properties and band gap broadening ofβ-Ag_(4)P_(2)S_(7) mainly originate from the alteration of the[Ag_(2)PS_(4)]^(2-)layer stacking configuration,which is driven by a temperature-induced irreversible phase transition.This work not only presents a new paradigm for designing high-performance NLO materials through phase transitions but also significantly advances the potential of temperature-mediated crystal engineering for optical applications.展开更多
The first alkali–metal selenate nonlinear optical (NLO) crystal,Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2),has been obtained by in situ hydrothermal synthesis.It crystallizes in the polar and noncentrosymmetric (NCS) ...The first alkali–metal selenate nonlinear optical (NLO) crystal,Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2),has been obtained by in situ hydrothermal synthesis.It crystallizes in the polar and noncentrosymmetric (NCS) space group Cc (no.9).The structure of Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2) can be described as isolated [SeO_(4)]/[HSeO_(4)] tetrahedra connected by H-bonding interactions and Na–O bonds,forming a three-dimensional framework.Powder second-harmonic generation (SHG) measurements show that Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2) is phase-matching with a moderate SHG response of ca.1.6 times that of benchmark KH_(2)PO_(4).The UV-Vis-NIR spectrum shows that the title compound is a wide-band semiconductor with an optical band gap of 3.57 eV.The birefringence of Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2) was calculated to be 0.037 at 1064 nm.First-principles studies show that the [SeO_(4)]/[HSeO_(4)] tetrahedra are the main contributors to its NLO properties.This study indicates that pure selenate is a promising material system to afford NCS structures with SHG responses.展开更多
Infrared(IR)nonlinear optical(NLO)materials have attracted tremendous interest for civil and military applications,but it remains a great contemporary challenge to develop high-effciency NLO crystals that possess suff...Infrared(IR)nonlinear optical(NLO)materials have attracted tremendous interest for civil and military applications,but it remains a great contemporary challenge to develop high-effciency NLO crystals that possess suffciently high second-harmonic generation(SHG)effciencies coupled to wide transparency ranges and high laser damage thresholds.A series of new hydrous rare-earth iodates RE(IO_(3))_(3)·(H_(2)O)(RE=Y 1,Eu 2)and La_(2)(IO_(3))_(6)(H_(2)O)(3)have been synthesized through facile hydrothermal methods.1 and 2 are isostructural,crystallizing in the polar space group P21,while 3 crystallizes in the polar space group Pc.1-3 feature three-dimensional(3D)frameworks composed of alternately connected corner-shared dis torted[REO_(x)]polyhedra(RE=Y,Eu,and La;x=8,9)and[IO_(3)]^(−)groups.Optical studies showed that 1–3 exhibit good NLO properties,including strong SHG intensities(3.0×(1),4.5×(2),and 1.5×KH_(2)PO_(4)(3)),large band gaps(4.12(1),4.36(2),and 4.24 eV(3),with 2 possessing the largest band gap among the known SHG-active rare-earth-based iodates,high laser damage thresholds(LDT)(53×(1),43×(2),and 44×AgGaS_(2)(3)),and wide transparency ranges(ca.3.0–11.3μm)in the mid-IR region covering two criti cal IR transparency windows;1–3 are therefore potential candidate NLO materials.Density functional theory calculations on 1–3 confirm that their strong SHG responses and large band gaps are mainly derived from the synergistic effect of[IO_(3)]^(−)groups and rare-earth oxide polyhedra[REOx]in their 3D frameworks.We conclude that the introduction of rare-earth cations with moderate electropositivity into iodates may optimize the balance between SHG effciency and optical band gaps,the key requirement for high-performance NLO materials for practical applications.展开更多
The geometrical structures of Wells-Dawson derivatives[X-C(CH_(2)O)_(3)P_(2)M’_(3)M_(15)O_(59)]^(6-)(X=NO_(2),NH_(2),and CH_(3),M’=V and Nb,M=W and Mo)have been calculated by the density functional theory(DFT)method...The geometrical structures of Wells-Dawson derivatives[X-C(CH_(2)O)_(3)P_(2)M’_(3)M_(15)O_(59)]^(6-)(X=NO_(2),NH_(2),and CH_(3),M’=V and Nb,M=W and Mo)have been calculated by the density functional theory(DFT)method.The results show that the distances of P…P and P…C are controlled by the{M’_(3)}triads,and{M’_(3)}triads also affect the sizes of W_(6) hexagonal belts.The second-order polarizabilities and origin of nonlinear optical(NLO)properties of those clusters have been investigated by a time-dependent density functional theory(TDDFT)method.The NLO property analysis reveals that[X-C(CH_(2)O)3P_(2)V_(3)Mo_(15)O_(59)]^(6-)(X=NH_(2))anions have the largest β_(vec) values,75.064×10^(-30) esu.Grafting electron donors to POM clusters is an efficient way to improve the NLO response.The major electron transition orbitals show that the charge transfer from the organic groups to the metal atoms is responsible for the NLO properties of these polyoxometalates.展开更多
Low-dimensional hybrid organic-inorganic chiral perovskites with intrinsic non-centrosymmetric structures have shown promising potential for second-order nonlinear optical applications due to their structural diversit...Low-dimensional hybrid organic-inorganic chiral perovskites with intrinsic non-centrosymmetric structures have shown promising potential for second-order nonlinear optical applications due to their structural diversity and large lattice distortions.Simultaneously,“structure-level”low-dimensional single crystal perovskites have attracted wide attention to meet the increasing demand of on-chip integrated nonlinear optical devices.Herein,we synthesized two new chiral hybrid 0D perovskites(R/S-MBA)_(4)Bi_(2)Cl_(10)based on the non-toxic element bismuth by introducing chiral R/S-MBA as the organic component.The highly ordered assembly microwire arrays were further prepared using a capillary-bridge confined technique.These high-crystallinity chiral perovskite microwire arrays preserve their structures with high distortion levels and achieve high-efficiency frequency conversion across a wide range of bands and different polarization states with a high polarization ratio of up to 0.992,which is superior to those of the corresponding polycrystalline films that cause undesirable light scattering.Such non-toxic Bi-based low-dimensional chiral perovskite single-crystalline microwire arrays with excellent NLO performances might provide a strategy for NLO-integrated applications in advancing photonic devices.展开更多
The exploration of new infrared(IR)nonlinear optical(NLO)crystals with large second-harmonic generation(SHG)responses and high laser-induced damage thresholds(LIDTs)concurrently is urgently needed and challenging.Here...The exploration of new infrared(IR)nonlinear optical(NLO)crystals with large second-harmonic generation(SHG)responses and high laser-induced damage thresholds(LIDTs)concurrently is urgently needed and challenging.Herein,the first-type of noncentrosymmetric(NCS)alkali metal Ag-based thiophosphates KAg_(2)PS_(4)(1)and(Na_(0.30)K_(0.70))Ag_(2)PS_(4)(2)were successfully synthesized using a high-temperature solid-state method.展开更多
In this paper we consider the existence of infinitely many positive solutions for second order nonlinear eigenvalue problem with singular coefficient function. By the use of Krasnosel'skii fixed point theorem of c...In this paper we consider the existence of infinitely many positive solutions for second order nonlinear eigenvalue problem with singular coefficient function. By the use of Krasnosel'skii fixed point theorem of cone expansion-compression type we give several sufficient conditions.展开更多
This paper concerns the calculation of the wave trough exceedance probabilities in a nonlinear sea. The calculations have been carried out by incorporating a second order nonlinear wave model into an asymptotic method...This paper concerns the calculation of the wave trough exceedance probabilities in a nonlinear sea. The calculations have been carried out by incorporating a second order nonlinear wave model into an asymptotic method. This is a new approach for the calculation of the wave trough exceedance probabilities, and, as all of the calculations are performed in the probability domain, avoids the need for long time-domain simulations. The proposed asymptotic method has been applied to calculate the wave trough depth exceedance probabilities of a sea state with the surface elevation data measured at the coast of Yura in the Japan Sea. It is demonstrated that the proposed new method can offer better predictions than the theoretical Rayleigh wave trough depth distribution model. The calculated results by using the proposed new method have been further compared with those obtained by using the Arhan and Plaisted nonlinear distribution model and the Toffoli et al.’s wave trough depth distribution model, and its accuracy has been once again substantiated. The research findings obtained from this study demonstrate that the proposed asymptotic method can be readily utilized in the process of designing various kinds of ocean engineering structures.展开更多
The title compound of isonicotinato lead（Ⅱ） [Pb（C5H4NCOO）2] has been optimized at B3LYP/LANL2DZ level of theory and calculated results show that the lead（Ⅱ） ion adopts 4-coordinate geometry. Atomic charge dist...The title compound of isonicotinato lead（Ⅱ） [Pb（C5H4NCOO）2] has been optimized at B3LYP/LANL2DZ level of theory and calculated results show that the lead（Ⅱ） ion adopts 4-coordinate geometry. Atomic charge distributions indicate that during forming the title compound, each isonicotinic acid ion transfers -0.452 e to lead（Ⅱ） ion. The electronic spectra calculations show that there exist two absorption bands and the electronic transitions are mainly derived from the contribution of intraligand π→π^＊ transition and ligand-to-metal charge transfer （LMCT） transition. The thermodynamic properties of the title compound at different temperatures have been calculated and corresponding relations between property and temperature have also been obtained. The calculation of the second order optical nonlinearity was carried out, and the molecular hyperpolarizability was 3.62365^＊10^-30 esu.展开更多
In this paper,we study the existence of quasi-periodic solutions and the bound- edness of solutions for a wide class nonlinear differential equations of second order.Using the KAM theorem of reversible systems and the...In this paper,we study the existence of quasi-periodic solutions and the bound- edness of solutions for a wide class nonlinear differential equations of second order.Using the KAM theorem of reversible systems and the theory of transformations,we obtain the existence of quasi-periodic solutions and the boundedness of solutions under some reasonable conditions.展开更多
P91 steel is an important bearing material used in nuclear power plants. The study of its mechanical degradation behavior is important for ensuring safe operation. The relationship between the dislocation density of P...P91 steel is an important bearing material used in nuclear power plants. The study of its mechanical degradation behavior is important for ensuring safe operation. The relationship between the dislocation density of P91 steel under different strains and the corresponding nonlinear ultrasonic parameter β was studied. The dislocation density of strained samples was estimated by X-ray diffraction. Nonlinear ultrasonic testing was conducted to evaluate β, showing that this value increased with increasing dislocation density induced by different tensile elongations. It was shown that the ultrasonic secondharmonic generation technique can effectively evaluate the degradation behavior of metallic materials, and the prediction of the residual life of bearing parts in service can be made based on β and the dislocation density.展开更多
In this paper,we discuss the oscillatory behavior of a class of nonlinear neutral perturbed dynamic equations on time scales.Some new oscillation criteria are obtained for such dynamic equations.Finally,an example tha...In this paper,we discuss the oscillatory behavior of a class of nonlinear neutral perturbed dynamic equations on time scales.Some new oscillation criteria are obtained for such dynamic equations.Finally,an example that dwells upon the sharp conditions of our result is also included.展开更多
For diethylenetriamino-trioxo-molybdenum（Ⅵ）, density functional theory （DFT） method calculations of the structure, atomic charge distributions, electronic spectra, natural population analyses and thermodynamic pr...For diethylenetriamino-trioxo-molybdenum（Ⅵ）, density functional theory （DFT） method calculations of the structure, atomic charge distributions, electronic spectra, natural population analyses and thermodynamic properties at different temperatures have been performed by B3LYP method using LANL2DZ, CEP-121G and CEP-31G basis sets, respectively. The calculated results show that B3LYP/LANL2DZ method can best reproduce the molecular structure. The atomic charge distribution analyses indicate that during forming the complex, the ligand of diethylenetriamine donates negative charges to MoO3 and these charges are accepted by molybdenum（Ⅵ） atom as well as three oxygen atoms. The electronic spectra calculations indicate that B3LYP/ LANL2DZ results are nearest to experimental data among the three methods and electronic transitions are mainly derived from the contribution of bands π→π^＊. The calculation of the second order optical nonlinearity was carried out, and the molecular hyperpolarizability was 0.7881^＊10^30 esu.展开更多
文摘Four phenoxysilicon networks for nonlinear optical (NLO) applications were designed and prepared by an extended sol-gel process without additional H2O and catalyst. All poled polymer network films possess high second-order nonlinear optical coefficients (d(33)) Of 10(-7)similar to 10(-8) esu. The investigation of NLO temporal stability at room temperature and elevated temperature (120 degreesC) indicated that these films exhibit high d(33) stability because the orientation of the chromophores are locked in the phenoxysilicon organic/inorganic networks.
文摘By the generalized Riccati transformation and the integral averaging technique, some sufficient conditions of oscillation of the solutions for second order nonlinear differential equations with damping were discussed.Some sufficient oscillation criteria for previous equations were built up.Some oscillation criteria have been expanded and strengthened in some other known results.
文摘On the basis of ZINDO method and according to the sum over states(SOS) expression, the program is devised for the calculation of nonlinear second order optical susceptibilites β ijk and studying how different substituents on the phenyl ring attached to the atom silicon influence on the nonlinear second order optical properties of substituted silane series of molecules. The properties of (CH 3) 3Si? ?has been studied particularly. The effect of the length of silica chains on the calculated values has been studied too. The regularity summarized from the calculated results has been explained micromechanically.
文摘Films were prepared from mixtures of copolymers of 4-nitro-4'-[N-methylacryloyloxyethyl, N'-ethyl] amino azobenzene with glycidyl methacrylate (chromophore content: 6 mol%) and copolymers containing anhydride units, which was obtained by the reaction of 4-nitro-4'-[N-hydroxyethyl, N'-ethyl] amino azobenzene with polymethacryloyl chloride (chromophore content: 25 mol %). During thermal poling process the anhydride reacts with the epoxy group and the resulting crosslinked network structure will stabilize the second harmonic generation in the poled film. The second harmonic generation of the poled film shows a maximum with the variation of composition this is presumed to be due to the effects of the increasing of concentration, orientation order as well as orientation stability of chromophore groups during crosslinking.
文摘Second order nonlinear optical active 2,3-dichloro-5,6-dicyanopyrazine (DCDCP) and its monoamine-substituted derivatives had been synthesized. Their facile synthesis, high melt point, high incidence af substantial SHG activity and increased transparency inthe blue and near infrared make this class compounds appealling for further investigation.
文摘Several oscillation criteria are given for the second order nonlinear differential equation with damped term of the form [α(t)(y'(t))σ]' +p(t)(y'(t))σ+ q(t)f(y(t)) = 0, where α∈C(R, (0,∞)), p(t) and q(t) are allowed to change sign on [t0, ∞), and f∈C1 (R, R) such that xf(x) > 0 for x ≠0. Our results improve and extend some known oscillation criteria. Examples are inserted to illustrate our results.
文摘Some new oscillation theorems are established for the second order nonlinear differential equations with damping of the form where p（t） and q（t） are allowed to change sign on [t0,∞).
基金supported by the National Natural Science Foundation of China(No.62275042)the Institute of Chemical Materials,China Academy of Engineering Physics(TCGH0319)+1 种基金the Sichuan Province Key Research&Development Cooperation Project(2024YFHZ0348)J.Wu thanks Tianfu Jiangxi Lab for financial support.
文摘Temperature-induced phase transitions offer a promising route to engineer nonlinear optical materials,particularly for infrared applications where conventional design approaches face fundamental limitations.Herein,a temperature-induced centrosymmetric(CS)to noncentrosymmetric(NCS)irreversible phase transition strategy was employed to successfully prepare a novel NCS diamond-like(DL)chalcogenide,β-Ag_(4)P_(2)S_(7),which was derived from the CS phaseα-Ag_(4)P_(2)S_(7) transformation.Structural analysis reveals that this transformation involves a reorganization of[Ag_(2)PS_(4)]^(2-)layers from an AA’AA’to AA’A’’AA’A’’stacking pattern,facilitated by bridging[Ag1S_(4)]^(7-)tetrahedra.β-Ag_(4)P_(2)S_(7) has exceptional IR NLO properties,including a strong phase-matchable second-harmonic generation(SHG)response(1.02×AgGaS2)and a wide band gap of 2.90 eV(the largest one in ternary Ag-based DL chalcogenides),which balances excellent NLO response with a wide band gap.Further structure–property relationship analyses show that superior NLO properties and band gap broadening ofβ-Ag_(4)P_(2)S_(7) mainly originate from the alteration of the[Ag_(2)PS_(4)]^(2-)layer stacking configuration,which is driven by a temperature-induced irreversible phase transition.This work not only presents a new paradigm for designing high-performance NLO materials through phase transitions but also significantly advances the potential of temperature-mediated crystal engineering for optical applications.
基金supported by the National Natural Science Foundation of China(nos.51432006 and 52002276)the Ministry of Education of China for the Changjiang Innovation Research Team(no.IRT14R23)+2 种基金the Ministry of Education and the State Administration of Foreign Experts Affairs for the 111 Project(no.B13025)the Innovation Program of Shanghai Municipal Education Commission.C.W.thanks the National and Shanghai Postdoctoral Program for Innovative Talents(no.BX201800216 and 2018192)the Australian Research Council for support(DP170100411).
文摘The first alkali–metal selenate nonlinear optical (NLO) crystal,Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2),has been obtained by in situ hydrothermal synthesis.It crystallizes in the polar and noncentrosymmetric (NCS) space group Cc (no.9).The structure of Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2) can be described as isolated [SeO_(4)]/[HSeO_(4)] tetrahedra connected by H-bonding interactions and Na–O bonds,forming a three-dimensional framework.Powder second-harmonic generation (SHG) measurements show that Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2) is phase-matching with a moderate SHG response of ca.1.6 times that of benchmark KH_(2)PO_(4).The UV-Vis-NIR spectrum shows that the title compound is a wide-band semiconductor with an optical band gap of 3.57 eV.The birefringence of Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2) was calculated to be 0.037 at 1064 nm.First-principles studies show that the [SeO_(4)]/[HSeO_(4)] tetrahedra are the main contributors to its NLO properties.This study indicates that pure selenate is a promising material system to afford NCS structures with SHG responses.
基金supported by the National Natural Science Foundation of China(no.51432006)the Ministry of Education of China for the Changjiang Innovation Research Team(no.IRT13R24)+1 种基金the Ministry of Education and the State Administration of Foreign Experts Affairs for the 111 Project(no.B13025)the Innovation Program of Shanghai Municipal Education Commission.M.G.H.and C.Z.thank the Australian Research Council for support(DP170100411).
文摘Infrared(IR)nonlinear optical(NLO)materials have attracted tremendous interest for civil and military applications,but it remains a great contemporary challenge to develop high-effciency NLO crystals that possess suffciently high second-harmonic generation(SHG)effciencies coupled to wide transparency ranges and high laser damage thresholds.A series of new hydrous rare-earth iodates RE(IO_(3))_(3)·(H_(2)O)(RE=Y 1,Eu 2)and La_(2)(IO_(3))_(6)(H_(2)O)(3)have been synthesized through facile hydrothermal methods.1 and 2 are isostructural,crystallizing in the polar space group P21,while 3 crystallizes in the polar space group Pc.1-3 feature three-dimensional(3D)frameworks composed of alternately connected corner-shared dis torted[REO_(x)]polyhedra(RE=Y,Eu,and La;x=8,9)and[IO_(3)]^(−)groups.Optical studies showed that 1–3 exhibit good NLO properties,including strong SHG intensities(3.0×(1),4.5×(2),and 1.5×KH_(2)PO_(4)(3)),large band gaps(4.12(1),4.36(2),and 4.24 eV(3),with 2 possessing the largest band gap among the known SHG-active rare-earth-based iodates,high laser damage thresholds(LDT)(53×(1),43×(2),and 44×AgGaS_(2)(3)),and wide transparency ranges(ca.3.0–11.3μm)in the mid-IR region covering two criti cal IR transparency windows;1–3 are therefore potential candidate NLO materials.Density functional theory calculations on 1–3 confirm that their strong SHG responses and large band gaps are mainly derived from the synergistic effect of[IO_(3)]^(−)groups and rare-earth oxide polyhedra[REOx]in their 3D frameworks.We conclude that the introduction of rare-earth cations with moderate electropositivity into iodates may optimize the balance between SHG effciency and optical band gaps,the key requirement for high-performance NLO materials for practical applications.
基金financial support by NSFC(20971020,21073030 and 21131001)Program for New Century Excellent Talents in University(NCET-10-318)+1 种基金Doctoral Fund of Ministry of Education of China(20100043120007)the Science and Technology Development Planning of Jilin Province(20100104 and 20100320).
文摘The geometrical structures of Wells-Dawson derivatives[X-C(CH_(2)O)_(3)P_(2)M’_(3)M_(15)O_(59)]^(6-)(X=NO_(2),NH_(2),and CH_(3),M’=V and Nb,M=W and Mo)have been calculated by the density functional theory(DFT)method.The results show that the distances of P…P and P…C are controlled by the{M’_(3)}triads,and{M’_(3)}triads also affect the sizes of W_(6) hexagonal belts.The second-order polarizabilities and origin of nonlinear optical(NLO)properties of those clusters have been investigated by a time-dependent density functional theory(TDDFT)method.The NLO property analysis reveals that[X-C(CH_(2)O)3P_(2)V_(3)Mo_(15)O_(59)]^(6-)(X=NH_(2))anions have the largest β_(vec) values,75.064×10^(-30) esu.Grafting electron donors to POM clusters is an efficient way to improve the NLO response.The major electron transition orbitals show that the charge transfer from the organic groups to the metal atoms is responsible for the NLO properties of these polyoxometalates.
基金supported by the Ji Hua Laboratory Science Program(grant no.X190251UZ190)the National Natural Science Foundation of China(22205077,52173190,and 21988102)+2 种基金the Ministry of Science and Technology(MOST)of China(2018YFA0208502,and 2018YFA0704803)the project funded by the China Postdoctoral Science Foundation(2021M701401)the Youth Innovation Promotion Association CAS(2018034).
文摘Low-dimensional hybrid organic-inorganic chiral perovskites with intrinsic non-centrosymmetric structures have shown promising potential for second-order nonlinear optical applications due to their structural diversity and large lattice distortions.Simultaneously,“structure-level”low-dimensional single crystal perovskites have attracted wide attention to meet the increasing demand of on-chip integrated nonlinear optical devices.Herein,we synthesized two new chiral hybrid 0D perovskites(R/S-MBA)_(4)Bi_(2)Cl_(10)based on the non-toxic element bismuth by introducing chiral R/S-MBA as the organic component.The highly ordered assembly microwire arrays were further prepared using a capillary-bridge confined technique.These high-crystallinity chiral perovskite microwire arrays preserve their structures with high distortion levels and achieve high-efficiency frequency conversion across a wide range of bands and different polarization states with a high polarization ratio of up to 0.992,which is superior to those of the corresponding polycrystalline films that cause undesirable light scattering.Such non-toxic Bi-based low-dimensional chiral perovskite single-crystalline microwire arrays with excellent NLO performances might provide a strategy for NLO-integrated applications in advancing photonic devices.
基金support by the National Natural Science Foundation of China(21771159,22071212)the Qinglan Project of Jiangsu Province of China,the Youth Innovation Promotion Association of Chinese Academy of Sciences(2022303)the Foundation of Excellent Doctoral Dissertation of Yangzhou University.
文摘The exploration of new infrared(IR)nonlinear optical(NLO)crystals with large second-harmonic generation(SHG)responses and high laser-induced damage thresholds(LIDTs)concurrently is urgently needed and challenging.Herein,the first-type of noncentrosymmetric(NCS)alkali metal Ag-based thiophosphates KAg_(2)PS_(4)(1)and(Na_(0.30)K_(0.70))Ag_(2)PS_(4)(2)were successfully synthesized using a high-temperature solid-state method.
文摘In this paper we consider the existence of infinitely many positive solutions for second order nonlinear eigenvalue problem with singular coefficient function. By the use of Krasnosel'skii fixed point theorem of cone expansion-compression type we give several sufficient conditions.
基金financially supported by the funding of an independent research project from the Chinese State Key Laboratory of Ocean Engineering(Grant No.GKZD010038)
文摘This paper concerns the calculation of the wave trough exceedance probabilities in a nonlinear sea. The calculations have been carried out by incorporating a second order nonlinear wave model into an asymptotic method. This is a new approach for the calculation of the wave trough exceedance probabilities, and, as all of the calculations are performed in the probability domain, avoids the need for long time-domain simulations. The proposed asymptotic method has been applied to calculate the wave trough depth exceedance probabilities of a sea state with the surface elevation data measured at the coast of Yura in the Japan Sea. It is demonstrated that the proposed new method can offer better predictions than the theoretical Rayleigh wave trough depth distribution model. The calculated results by using the proposed new method have been further compared with those obtained by using the Arhan and Plaisted nonlinear distribution model and the Toffoli et al.’s wave trough depth distribution model, and its accuracy has been once again substantiated. The research findings obtained from this study demonstrate that the proposed asymptotic method can be readily utilized in the process of designing various kinds of ocean engineering structures.
基金This work was supported by the Natural Science Foundation of Shandong Province (No. Y2002B06)
文摘The title compound of isonicotinato lead（Ⅱ） [Pb（C5H4NCOO）2] has been optimized at B3LYP/LANL2DZ level of theory and calculated results show that the lead（Ⅱ） ion adopts 4-coordinate geometry. Atomic charge distributions indicate that during forming the title compound, each isonicotinic acid ion transfers -0.452 e to lead（Ⅱ） ion. The electronic spectra calculations show that there exist two absorption bands and the electronic transitions are mainly derived from the contribution of intraligand π→π^＊ transition and ligand-to-metal charge transfer （LMCT） transition. The thermodynamic properties of the title compound at different temperatures have been calculated and corresponding relations between property and temperature have also been obtained. The calculation of the second order optical nonlinearity was carried out, and the molecular hyperpolarizability was 3.62365^＊10^-30 esu.
文摘In this paper,we study the existence of quasi-periodic solutions and the bound- edness of solutions for a wide class nonlinear differential equations of second order.Using the KAM theorem of reversible systems and the theory of transformations,we obtain the existence of quasi-periodic solutions and the boundedness of solutions under some reasonable conditions.
基金Item Sponsored by National Natural Science Foundation of China(61171145,11274226)
文摘P91 steel is an important bearing material used in nuclear power plants. The study of its mechanical degradation behavior is important for ensuring safe operation. The relationship between the dislocation density of P91 steel under different strains and the corresponding nonlinear ultrasonic parameter β was studied. The dislocation density of strained samples was estimated by X-ray diffraction. Nonlinear ultrasonic testing was conducted to evaluate β, showing that this value increased with increasing dislocation density induced by different tensile elongations. It was shown that the ultrasonic secondharmonic generation technique can effectively evaluate the degradation behavior of metallic materials, and the prediction of the residual life of bearing parts in service can be made based on β and the dislocation density.
基金Supported by the NNSF of China(11161049)the SF of the Zhangjiakou Bureau of Science and Technology(1112027B-1)
文摘In this paper,we discuss the oscillatory behavior of a class of nonlinear neutral perturbed dynamic equations on time scales.Some new oscillation criteria are obtained for such dynamic equations.Finally,an example that dwells upon the sharp conditions of our result is also included.
基金This work was supported by the Natural Science Foundation of Shandong Province (No. Y2002B06)
文摘For diethylenetriamino-trioxo-molybdenum（Ⅵ）, density functional theory （DFT） method calculations of the structure, atomic charge distributions, electronic spectra, natural population analyses and thermodynamic properties at different temperatures have been performed by B3LYP method using LANL2DZ, CEP-121G and CEP-31G basis sets, respectively. The calculated results show that B3LYP/LANL2DZ method can best reproduce the molecular structure. The atomic charge distribution analyses indicate that during forming the complex, the ligand of diethylenetriamine donates negative charges to MoO3 and these charges are accepted by molybdenum（Ⅵ） atom as well as three oxygen atoms. The electronic spectra calculations indicate that B3LYP/ LANL2DZ results are nearest to experimental data among the three methods and electronic transitions are mainly derived from the contribution of bands π→π^＊. The calculation of the second order optical nonlinearity was carried out, and the molecular hyperpolarizability was 0.7881^＊10^30 esu.
