One of the most significant challenges in commercializing organic second-order nonlinear optical(NLO)materials lies in the inherent trade-off between nonlinearity and stability.A key factor in mitigating this compromi...One of the most significant challenges in commercializing organic second-order nonlinear optical(NLO)materials lies in the inherent trade-off between nonlinearity and stability.A key factor in mitigating this compromise is achieving precise temporal synchronization between the formation of the cross-linked network and the establishment of an optimal non-centrosymmetric alignment of the chromophores.Guided by this principle,we developed a series of NLO polymers incorporating multiple ether chains with low rotational energy barriers,which facilitate molecular reorientation during electric field poling,thereby enhancing the NLO response effectively.Combined with an optimized photocrosslinking strategy,the resulting PX4o/PETMP doped film achieved large macroscopic NLO coefficient of 190 pm·V^(-1)and thermal degradation temperature as high as 120℃.This work offers a universal approach to alleviating the“nonlinearity-stability”trade-off in a wide range of polymeric systems.展开更多
Landslides pose a formidable natural hazard across the Qinghai-Tibet Plateau(QTP),endangering both ecosystems and human life.Identifying the driving factors behind landslides and accurately assessing susceptibility ar...Landslides pose a formidable natural hazard across the Qinghai-Tibet Plateau(QTP),endangering both ecosystems and human life.Identifying the driving factors behind landslides and accurately assessing susceptibility are key to mitigating disaster risk.This study integrated multi-source historical landslide data with 15 predictive factors and used several machine learning models—Random Forest(RF),Gradient Boosting Regression Trees(GBRT),Extreme Gradient Boosting(XGBoost),and Categorical Boosting(CatBoost)—to generate susceptibility maps.The Shapley additive explanation(SHAP)method was applied to quantify factor importance and explore their nonlinear effects.The results showed that:(1)CatBoost was the best-performing model(CA=0.938,AUC=0.980)in assessing landslide susceptibility,with altitude emerging as the most significant factor,followed by distance to roads and earthquake sites,precipitation,and slope;(2)the SHAP method revealed critical nonlinear thresholds,demonstrating that historical landslides were concentrated at mid-altitudes(1400-4000 m)and decreased markedly above 4000 m,with a parallel reduction in probability beyond 700 m from roads;and(3)landslide-prone areas,comprising 13%of the QTP,were concentrated in the southeastern and northeastern parts of the plateau.By integrating machine learning and SHAP analysis,this study revealed landslide hazard-prone areas and their driving factors,providing insights to support disaster management strategies and sustainable regional planning.展开更多
Polarization-dependent second harmonic generation is a widely utilized technique for characterizing symmetry.However,in collinear reflective geometry,the essential beam-splitting device significantly influences both t...Polarization-dependent second harmonic generation is a widely utilized technique for characterizing symmetry.However,in collinear reflective geometry,the essential beam-splitting device significantly influences both the polarization state of the fundamental and harmonic beams,thereby affecting the accuracy of the obtained second-order nonlinear susceptibility.Here,we propose a data correction method to solve this problem to obtain accurate secondorder nonlinear susceptibility.The feasibility and generality of the method are demonstrated through theoretical and experimental validation.展开更多
The second-order effect of axial force on horizontal vibrating characteristics of a large-diameter pipe pile is theoretically investigated.Governing equations of the pile-soil system are established based on elastodyn...The second-order effect of axial force on horizontal vibrating characteristics of a large-diameter pipe pile is theoretically investigated.Governing equations of the pile-soil system are established based on elastodynamics.Threedimensional wave equations of soil are decoupled through differential transformation and variable separation.Consequently,expressions of soil displacements and horizontal resistances can be obtained.An analytical solution of the pile is derived based on continuity conditions between the pile and soil,subsequently from which expressions of the complex impedances are deduced.Analyses are carried out to examine the second-order effect of axial force on the horizontal vibrating behavior of the pipe pile.Some conclusions can be summarized as follows： stiffness and damping factors are decreased with the application of axial force on the pile head; distributions of the pile horizontal displacement and rotation angle are regenerated due to the second-order effect of the applied axial force; and redistributions of the bending moment and shearing force occur due to the second-order effect of the applied axial force.展开更多
A chiral lanthanide metal-organic framework based on enantiopure camphoric acid （D-H2cam）, [Nd3（D-cam）8（H2O）4Cl]n （1）, has been synthesized and characterized by single-crystal X-ray structural analysis, elemen...A chiral lanthanide metal-organic framework based on enantiopure camphoric acid （D-H2cam）, [Nd3（D-cam）8（H2O）4Cl]n （1）, has been synthesized and characterized by single-crystal X-ray structural analysis, elemental analysis, IR, thermal gravimetric, and X-ray powder diffraction. Crystal data for the title compound are as follows： orthorhombic system, space group P212121 with a = 13.8287（7）, b = 14.0715（7）, c = 25.7403（12） A^°, V = 5008.8（4） A^°3, Mr = 1333.08, Z = 4, F（000） = 2644, Dc = 1.768 g/cm^3, μ（MoKα） = 3.189 mm^-1, the final R = 0.0351 and wR = 0.0814 （I 〉 2σ（I））. Compound 1 displays an 8-connected bcu topology 3D framework and hydrogen-bonding interactions stabilize the solid-state structure. The vibrational circular dichroism （VCD） spectrum and second-order nonlinear optical effect of compound 1 have been studied in the solid state.展开更多
The effect from the interaction of the alternating current(AC)magnetic field with kilogram-level test mass(TM)limits the detectivity of the TianQin space-based gravitational wave detection.The quantifed effect require...The effect from the interaction of the alternating current(AC)magnetic field with kilogram-level test mass(TM)limits the detectivity of the TianQin space-based gravitational wave detection.The quantifed effect requires the determination of the AC magnetic susceptibilityχ(f)of the TM.A torque method is proposed to measure theχ(f)of kg-level samples at the mHz band with a precision of 1×10^(-7).Combined with our previous work[Phys.Rev.Appl.18044010(2022)],the general frequency-dependent susceptibility of the alloy cube with side length L and electrical conductivityσis determined asχ(f)=χ0+(0.24±0.01)σμ0L^(2)f from 0.1 mHz to 1 Hz.The determination is helpful for the preliminary estimation of the in-band eddy current efect in the TianQin noise budget.The technique can be adopted to accurately measureχ(f)of the actual TM in other precision experiments,where the magnetic noise is a signifcant detection limit.展开更多
The profilc of susceptibility uear the surfuce of a senni-ifinite frrclectric is calculatel from Luidau free energy.In surfunce ferroclectric plase,the susceptibility is reduced at surface for|δ|<<βand much en...The profilc of susceptibility uear the surfuce of a senni-ifinite frrclectric is calculatel from Luidau free energy.In surfunce ferroclectric plase,the susceptibility is reduced at surface for|δ|<<βand much enhanced for|δ|-β,whereδandβare the.extrapolation le1ngth and tle coluerent lengtl respectiv:ly.In ferroelectric phase,the surface susceptibility is gcllcrally reduced for8<0.But the crurve is not molnotonic,there is a mininum in the surface layer.Forδ>0,the surface susceptibility is.redced forδ<<βand enhanced fo rδ-β.The curve has a maxiln11 in the srface layer.展开更多
In this paper,we investigate the photon correlations and the statistical properties of light produced by an optical cavity with an embedded quantum well interacting with squeezed light.We show that the squeezed source...In this paper,we investigate the photon correlations and the statistical properties of light produced by an optical cavity with an embedded quantum well interacting with squeezed light.We show that the squeezed source substantially improves the intensity of the emitted light and generates a narrowing and a duplication of the spectrum peaks.With a strong dependence on frequency detuning,the cavity produces considerably squeezed radiation,and perfect squeezing is predicted for weak light–matter interactions.Furthermore,the system under consideration presents a bunching effect of the transmitted radiation resulting from weak pumping of the coherent field.The results obtained may have potential applications in the fields of very accurate measurement and quantum computing.展开更多
We theoretically study the effect of Kerr effect on the second-order nonlinearity induced transparency in a double-resonant optical cavity system.We show that in the presence of the Kerr effect,as the strength of the ...We theoretically study the effect of Kerr effect on the second-order nonlinearity induced transparency in a double-resonant optical cavity system.We show that in the presence of the Kerr effect,as the strength of the Kerr effect increases,the absorption curve exhibits an asymmetric-symmetric-asymmetric transition,and the zero absorption point shifts with the increase of the Kerr effect.Furthermore,by changing the strength of the Kerr effect,we can control the width of the transparent window,and the position of the zero-absorption point and meanwhile change the left and right width of the absorption peak.The asymmetry absorption curve can be employed to improve the quality factor of the cavity when the frequency detuning is tuned to be around the right peak.The simple dependence of the zeroabsorption point on the strength of Kerr effect suggests that the strength of Kerr effect can be measured by measuring the position of the zero-absorption point in a possible application.展开更多
Dynamic equations of motional flexible beam elements were derived considering second-order effect. Non-linear finite element method and three-node Euler-Bernoulli beam elements were used. Because accuracy is higher in...Dynamic equations of motional flexible beam elements were derived considering second-order effect. Non-linear finite element method and three-node Euler-Bernoulli beam elements were used. Because accuracy is higher in non-linear structural analysis,three-node beam elements are used to deduce shape functions and stiffness matrices in dynamic equations of flexible elements. Static condensation method was used to obtain the finial dynamic equations of three-node beam elements. According to geometrical relations of nodal displacements in concomitant and global coordinate system,dynamic equations of elements can be transformed to global coordinate system by concomitant coordinate method in order to build the global dynamic equations. Analyzed amplitude condition of flexible arm support of a port crane,the results show that second-order effect should be considered in kinetic-elastic analysis for heavy load machinery of big flexibility.展开更多
Large magnetic entropy change(△S_(M))can realize a prominent heat transformation under the magnetic field and directly strengthen the efficacy of the magnetocaloric effect,which provides a pioneering environmentally ...Large magnetic entropy change(△S_(M))can realize a prominent heat transformation under the magnetic field and directly strengthen the efficacy of the magnetocaloric effect,which provides a pioneering environmentally friendly solidstate strategy to improve refrigeration capacities and efficiencies.The second-order magnetic transition(SOMT)materials have broader△S_(M) peaks without thermal hysteresis,making them highly attractive in magnetic refrigeration,especially in the room temperature range.Here,we report a significant enhancement of△S_(M) at room temperature in single-crystal Mn_(5)Ge_(3).In this SOMT system,we realize a 60%improvement of-△S_(M)^(max) from 3.5 J/kg·K to 5.6 J/kg·K at T=300 K.This considerable enhancement of△S_(M) is achieved by intentionally introducing strain energy through high-pressure constrained deformation.Both experimental results and Monte Carlo simulations demonstrate that the enhancement of△S_(M) originates from the microscopic strain and lattice deformation induced by strain energy after deformation.This strain energy will reconstruct the energy landscape of this ferromagnetic system and enhance magnetization,resulting in a giant intensity of magnetocaloric responses.Our findings provide an approach to increase magnetic entropy change and may give fresh ideas for exploring advanced magnetocaloric materials.展开更多
A novel transition appeared above thc glass transition temperature of chlorinated polyethylene (CPE) for binaryblends of CPE and additives such as organic small molecules or oligomers. This transition was assigned to ...A novel transition appeared above thc glass transition temperature of chlorinated polyethylene (CPE) for binaryblends of CPE and additives such as organic small molecules or oligomers. This transition was assigned to the dissociation ofintermolecular hydrogen bonds between the polymer ard additive within the edditive rich phase. Of particular interest is thata novel pyramid crystal was observed in the annealed CPE/hindered phenol blends. Another intriguing observation is thatthese polymer/small molecule blends organized by intermolecular hydrogen bonding have several potential properties, suchas shape-memorization, self-restoration, self-adhesiveness and super damping.展开更多
The magneto-optical Kerr effect susceptometry technique is proposed to determine the uniaxial magnetic anisotropy （UMA） constant Ku. The magnetic properties of Cu/Fe/SiO2/Si grown by dc magnetron sputtering were inv...The magneto-optical Kerr effect susceptometry technique is proposed to determine the uniaxial magnetic anisotropy （UMA） constant Ku. The magnetic properties of Cu/Fe/SiO2/Si grown by dc magnetron sputtering were investigated. The in-plane uniaxial magnetic anisotropy was probed by the magneto-optical Kerr effect （MOKE）. The value of UMA, Ku = 2.5 x 103 J/m3, was simulated from the field dependence of ac susceptibility along the hard axis according to the Stoner-Wohlfarth （S-W） model, which is consistent with Ku = 2.7~ 103 J/m3 calculated from the magnetic hysteresis loops. Our results show that the magneto-optical Kerr effect susceptometry can be employed to determine the magnetic anisotropy constant owing to its high sensitivity.展开更多
A perturbative approach is used to study the AC response of nonlinear composite media, which obey a current-field relation of the form with components having nonlinear response at finite frequencies. For a sinusoidal...A perturbative approach is used to study the AC response of nonlinear composite media, which obey a current-field relation of the form with components having nonlinear response at finite frequencies. For a sinusoidal applied field, we extend the local potential in terms of sinusoidal components at fundamental frequency and high-order harmonic frequencies to treat the nonlinear composites. For nonlinear composite media with a low concentrations of spherical inclusions, we give the formulae of the nonlinear effective AC susceptibility at the third harmonic frequency.展开更多
alculations of the nonlinear second-order optical susceptlbilities(β_(ijk))for sub- stituted tl1iophene derivative;with quinoidlike conformation are reported.These systetems possess small dipole moment;and large diff...alculations of the nonlinear second-order optical susceptlbilities(β_(ijk))for sub- stituted tl1iophene derivative;with quinoidlike conformation are reported.These systetems possess small dipole moment;and large differences between dipole mo- ments of ground and first-excited states.Geometry optimizations of the molecules investigated were carried out using AM 1 method.The calculations were performed using INDO/CI method comboned with a sum-over-states expression for β_(jik). The calculated results sbw that the second-order susceptibility is a function of the na- ture and location of substituents and is larger for disubstituted molecules than monosubstituted molecules. Bipolymeric thiophenemetmne with NH_2/NO_2 groups was calctilated to have a β_μof 79. 920 × 10￣(-30) esu. It was found that the NH_2 and NO_2 groups in above disubstituted molecules are pull-pull groups in ground states,but are usual push-pull groups in the first excited states.展开更多
A detailed analysis of the magnetic response of field-cooled type-I superconducting hollow cylinders shows that the so-called “paramagnetic Meissner effect” can take place in opportunely devised multiply connected s...A detailed analysis of the magnetic response of field-cooled type-I superconducting hollow cylinders shows that the so-called “paramagnetic Meissner effect” can take place in opportunely devised multiply connected superconductors. Adopting simple circuital analogs of the latter superconducting systems, the magnetic susceptibility of micro-cylinders with one or two holes is studied by means of energy considerations.展开更多
Objective:To evaluate the efficacy and side effects of praziquantel(PZQ) in the treatment of schistosomiasis in Ethiopia.Methods:In a cross-sectional study,stool specimens were collected from randomly selected 299 sch...Objective:To evaluate the efficacy and side effects of praziquantel(PZQ) in the treatment of schistosomiasis in Ethiopia.Methods:In a cross-sectional study,stool specimens were collected from randomly selected 299 school children in Shesha Kekele Elementary School,Wondo Genet, Southern Ethiopia,in April 2010.Stool specimens were examined using a single Kato-Katz thick smear for Schistosoma mansoni(5.mansoni) ova.Children who were found positive for S.mansoni were treated with a single oral dose of PZQ at 40 mg/kg bw and interviewed for treatment-related symptoms 24 hours after drug administration.Four weeks post-treatment,stool specimens were collected from the same children and examined following the same procedure as in the pretreatment.Drug efficacy was determined based on cure and egg reduction rates.Results:Pretreatment prevalence of S.mansoni infection was 74.9%with geometric mean egg count of 268. The evaluated generic PZQ produced an overall cure rate of 73.6%(P<0.000 1,OR:8.33,CI:5.3-13.1) and egg reduction rate of 68.2%(P=0.03,F=0.64).The cure rate showed significant association with age(x^2=H,P=0.004),the highest rate being observed in the 15-22 age group.83%of S. mansoni infected children showed various treatment-related symptoms,the most frerjiient being headache,nausea,and abdominal pain.These symptoms were associated with age(P<0.001) and pre-treatment intensity of infection(P<0.05).Conclusions:The present observations revealed relatively lower cure and egg reduction rates of the PZQ evaluated as compared to previous reports for other PZQ brands in Ethiopia.Hence,in depth studies are recommended to clarify whether the present relatively lower cure rate is the actual cure rate of the praziquantel evaluated,treatment failure,or reduced susceptibility of the parasite.Treatment-related side effects observed were transient and tolerable.展开更多
The large disc LaFe11.6Si1.4 alloy, which was prepared by medium-frequency induction furnace, was annealed at 1503 K for different time. The main phases were 1：13 phase in the edge parts of the large discs alloy; the...The large disc LaFe11.6Si1.4 alloy, which was prepared by medium-frequency induction furnace, was annealed at 1503 K for different time. The main phases were 1：13 phase in the edge parts of the large discs alloy; the impurity phases included α-Fe phase, LaFeSi phase, and even very small amount of La5Si3 phase. The amounts of impurity phases reduced with increasing in annealing time. The magnetic properties in the edge parts of the large discs LaFe11.6Si1.4 alloy were investigated. The magnetic susceptibility had an abrupt change at Curie temperature（TC） as the magnetization in M-T curves. The alloys had almost the same TC（191 K）, the magnetocaloric effect（MCE） and relative cooling power（RCP） increased with increasing in annealing time. In addition, for the same alloy, the magnetic hysteresis decreased with the increase in temperature.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22235006 and 22475157)Foundation of Hubei Scientific Committee(Nos.2024 AFA021 and 2024BAB014)Fundamental Research Funds for the Central Universities(No.2042025kf0009)。
文摘One of the most significant challenges in commercializing organic second-order nonlinear optical(NLO)materials lies in the inherent trade-off between nonlinearity and stability.A key factor in mitigating this compromise is achieving precise temporal synchronization between the formation of the cross-linked network and the establishment of an optimal non-centrosymmetric alignment of the chromophores.Guided by this principle,we developed a series of NLO polymers incorporating multiple ether chains with low rotational energy barriers,which facilitate molecular reorientation during electric field poling,thereby enhancing the NLO response effectively.Combined with an optimized photocrosslinking strategy,the resulting PX4o/PETMP doped film achieved large macroscopic NLO coefficient of 190 pm·V^(-1)and thermal degradation temperature as high as 120℃.This work offers a universal approach to alleviating the“nonlinearity-stability”trade-off in a wide range of polymeric systems.
基金The National Key Research and Development Program of China,No.2023YFC3206601。
文摘Landslides pose a formidable natural hazard across the Qinghai-Tibet Plateau(QTP),endangering both ecosystems and human life.Identifying the driving factors behind landslides and accurately assessing susceptibility are key to mitigating disaster risk.This study integrated multi-source historical landslide data with 15 predictive factors and used several machine learning models—Random Forest(RF),Gradient Boosting Regression Trees(GBRT),Extreme Gradient Boosting(XGBoost),and Categorical Boosting(CatBoost)—to generate susceptibility maps.The Shapley additive explanation(SHAP)method was applied to quantify factor importance and explore their nonlinear effects.The results showed that:(1)CatBoost was the best-performing model(CA=0.938,AUC=0.980)in assessing landslide susceptibility,with altitude emerging as the most significant factor,followed by distance to roads and earthquake sites,precipitation,and slope;(2)the SHAP method revealed critical nonlinear thresholds,demonstrating that historical landslides were concentrated at mid-altitudes(1400-4000 m)and decreased markedly above 4000 m,with a parallel reduction in probability beyond 700 m from roads;and(3)landslide-prone areas,comprising 13%of the QTP,were concentrated in the southeastern and northeastern parts of the plateau.By integrating machine learning and SHAP analysis,this study revealed landslide hazard-prone areas and their driving factors,providing insights to support disaster management strategies and sustainable regional planning.
基金This work was supported by the National Natural Science Foundation of China(No.U2230203)the Fundamental Research Funds for the Central Universities.
文摘Polarization-dependent second harmonic generation is a widely utilized technique for characterizing symmetry.However,in collinear reflective geometry,the essential beam-splitting device significantly influences both the polarization state of the fundamental and harmonic beams,thereby affecting the accuracy of the obtained second-order nonlinear susceptibility.Here,we propose a data correction method to solve this problem to obtain accurate secondorder nonlinear susceptibility.The feasibility and generality of the method are demonstrated through theoretical and experimental validation.
基金National Natural Science Foundation of China under Grant Nos.51622803 and 51708064the National Key Research and Development Program of China under Grant No.2016YFE0200100
文摘The second-order effect of axial force on horizontal vibrating characteristics of a large-diameter pipe pile is theoretically investigated.Governing equations of the pile-soil system are established based on elastodynamics.Threedimensional wave equations of soil are decoupled through differential transformation and variable separation.Consequently,expressions of soil displacements and horizontal resistances can be obtained.An analytical solution of the pile is derived based on continuity conditions between the pile and soil,subsequently from which expressions of the complex impedances are deduced.Analyses are carried out to examine the second-order effect of axial force on the horizontal vibrating behavior of the pipe pile.Some conclusions can be summarized as follows： stiffness and damping factors are decreased with the application of axial force on the pile head; distributions of the pile horizontal displacement and rotation angle are regenerated due to the second-order effect of the applied axial force; and redistributions of the bending moment and shearing force occur due to the second-order effect of the applied axial force.
基金supported by National Natural Science Foundation of China(21401147)Basic Research Program of Natural Science from Shaanxi Provincial Government(2015JQ2032)+2 种基金Scientific Research Program from Education Department of Shaanxi Provincial Government(2013JK0654)Opening Foundation from State Key Laboratory of Coordination Chemistry in Nanjing University(201219)the Program for Distinguished Young Scholars of Xi’an Polytechnic University(201403)
文摘A chiral lanthanide metal-organic framework based on enantiopure camphoric acid （D-H2cam）, [Nd3（D-cam）8（H2O）4Cl]n （1）, has been synthesized and characterized by single-crystal X-ray structural analysis, elemental analysis, IR, thermal gravimetric, and X-ray powder diffraction. Crystal data for the title compound are as follows： orthorhombic system, space group P212121 with a = 13.8287（7）, b = 14.0715（7）, c = 25.7403（12） A^°, V = 5008.8（4） A^°3, Mr = 1333.08, Z = 4, F（000） = 2644, Dc = 1.768 g/cm^3, μ（MoKα） = 3.189 mm^-1, the final R = 0.0351 and wR = 0.0814 （I 〉 2σ（I））. Compound 1 displays an 8-connected bcu topology 3D framework and hydrogen-bonding interactions stabilize the solid-state structure. The vibrational circular dichroism （VCD） spectrum and second-order nonlinear optical effect of compound 1 have been studied in the solid state.
基金supported by the National Key R&D Program of China(Grant No.2020YFC2200500)the Key Laboratory of Tian Qin Project(Sun Yat-sen University),Ministry of Education+1 种基金the National Natural Science Foundation of China(Grant Nos.12075325,12005308,and 11605065)the Doctoral Research Foundation Project of Hubei University of Arts and Science(Grant No.kyqdf2059017)。
文摘The effect from the interaction of the alternating current(AC)magnetic field with kilogram-level test mass(TM)limits the detectivity of the TianQin space-based gravitational wave detection.The quantifed effect requires the determination of the AC magnetic susceptibilityχ(f)of the TM.A torque method is proposed to measure theχ(f)of kg-level samples at the mHz band with a precision of 1×10^(-7).Combined with our previous work[Phys.Rev.Appl.18044010(2022)],the general frequency-dependent susceptibility of the alloy cube with side length L and electrical conductivityσis determined asχ(f)=χ0+(0.24±0.01)σμ0L^(2)f from 0.1 mHz to 1 Hz.The determination is helpful for the preliminary estimation of the in-band eddy current efect in the TianQin noise budget.The technique can be adopted to accurately measureχ(f)of the actual TM in other precision experiments,where the magnetic noise is a signifcant detection limit.
文摘The profilc of susceptibility uear the surfuce of a senni-ifinite frrclectric is calculatel from Luidau free energy.In surfunce ferroclectric plase,the susceptibility is reduced at surface for|δ|<<βand much enhanced for|δ|-β,whereδandβare the.extrapolation le1ngth and tle coluerent lengtl respectiv:ly.In ferroelectric phase,the surface susceptibility is gcllcrally reduced for8<0.But the crurve is not molnotonic,there is a mininum in the surface layer.Forδ>0,the surface susceptibility is.redced forδ<<βand enhanced fo rδ-β.The curve has a maxiln11 in the srface layer.
文摘In this paper,we investigate the photon correlations and the statistical properties of light produced by an optical cavity with an embedded quantum well interacting with squeezed light.We show that the squeezed source substantially improves the intensity of the emitted light and generates a narrowing and a duplication of the spectrum peaks.With a strong dependence on frequency detuning,the cavity produces considerably squeezed radiation,and perfect squeezing is predicted for weak light–matter interactions.Furthermore,the system under consideration presents a bunching effect of the transmitted radiation resulting from weak pumping of the coherent field.The results obtained may have potential applications in the fields of very accurate measurement and quantum computing.
基金Supported by the Key Scientific Research Plan of Colleges and Universities in Henan Province(23B140006)the National Natural Science Foundation of China(11965017)。
文摘We theoretically study the effect of Kerr effect on the second-order nonlinearity induced transparency in a double-resonant optical cavity system.We show that in the presence of the Kerr effect,as the strength of the Kerr effect increases,the absorption curve exhibits an asymmetric-symmetric-asymmetric transition,and the zero absorption point shifts with the increase of the Kerr effect.Furthermore,by changing the strength of the Kerr effect,we can control the width of the transparent window,and the position of the zero-absorption point and meanwhile change the left and right width of the absorption peak.The asymmetry absorption curve can be employed to improve the quality factor of the cavity when the frequency detuning is tuned to be around the right peak.The simple dependence of the zeroabsorption point on the strength of Kerr effect suggests that the strength of Kerr effect can be measured by measuring the position of the zero-absorption point in a possible application.
文摘Dynamic equations of motional flexible beam elements were derived considering second-order effect. Non-linear finite element method and three-node Euler-Bernoulli beam elements were used. Because accuracy is higher in non-linear structural analysis,three-node beam elements are used to deduce shape functions and stiffness matrices in dynamic equations of flexible elements. Static condensation method was used to obtain the finial dynamic equations of three-node beam elements. According to geometrical relations of nodal displacements in concomitant and global coordinate system,dynamic equations of elements can be transformed to global coordinate system by concomitant coordinate method in order to build the global dynamic equations. Analyzed amplitude condition of flexible arm support of a port crane,the results show that second-order effect should be considered in kinetic-elastic analysis for heavy load machinery of big flexibility.
基金Project supported by the National Key Research and Decelopment Program of China(Grant No.2021YFB3500302)the National Natural Science Foundation of China(Grant Nos.U22A20116 and 52371200)the Innovation Capability Improvement Project of Hebei Province,China(Grant No.22567605H)。
文摘Large magnetic entropy change(△S_(M))can realize a prominent heat transformation under the magnetic field and directly strengthen the efficacy of the magnetocaloric effect,which provides a pioneering environmentally friendly solidstate strategy to improve refrigeration capacities and efficiencies.The second-order magnetic transition(SOMT)materials have broader△S_(M) peaks without thermal hysteresis,making them highly attractive in magnetic refrigeration,especially in the room temperature range.Here,we report a significant enhancement of△S_(M) at room temperature in single-crystal Mn_(5)Ge_(3).In this SOMT system,we realize a 60%improvement of-△S_(M)^(max) from 3.5 J/kg·K to 5.6 J/kg·K at T=300 K.This considerable enhancement of△S_(M) is achieved by intentionally introducing strain energy through high-pressure constrained deformation.Both experimental results and Monte Carlo simulations demonstrate that the enhancement of△S_(M) originates from the microscopic strain and lattice deformation induced by strain energy after deformation.This strain energy will reconstruct the energy landscape of this ferromagnetic system and enhance magnetization,resulting in a giant intensity of magnetocaloric responses.Our findings provide an approach to increase magnetic entropy change and may give fresh ideas for exploring advanced magnetocaloric materials.
文摘A novel transition appeared above thc glass transition temperature of chlorinated polyethylene (CPE) for binaryblends of CPE and additives such as organic small molecules or oligomers. This transition was assigned to the dissociation ofintermolecular hydrogen bonds between the polymer ard additive within the edditive rich phase. Of particular interest is thata novel pyramid crystal was observed in the annealed CPE/hindered phenol blends. Another intriguing observation is thatthese polymer/small molecule blends organized by intermolecular hydrogen bonding have several potential properties, suchas shape-memorization, self-restoration, self-adhesiveness and super damping.
基金Project supported by the National Basic Research Program of China(Grant Nos.2009CB929201,2011CB921801,and 2012CB933102)the National Natural Science Foundation of China(Grant Nos.50931006,11034004,51021061,and 11274033)
文摘The magneto-optical Kerr effect susceptometry technique is proposed to determine the uniaxial magnetic anisotropy （UMA） constant Ku. The magnetic properties of Cu/Fe/SiO2/Si grown by dc magnetron sputtering were investigated. The in-plane uniaxial magnetic anisotropy was probed by the magneto-optical Kerr effect （MOKE）. The value of UMA, Ku = 2.5 x 103 J/m3, was simulated from the field dependence of ac susceptibility along the hard axis according to the Stoner-Wohlfarth （S-W） model, which is consistent with Ku = 2.7~ 103 J/m3 calculated from the magnetic hysteresis loops. Our results show that the magneto-optical Kerr effect susceptometry can be employed to determine the magnetic anisotropy constant owing to its high sensitivity.
文摘A perturbative approach is used to study the AC response of nonlinear composite media, which obey a current-field relation of the form with components having nonlinear response at finite frequencies. For a sinusoidal applied field, we extend the local potential in terms of sinusoidal components at fundamental frequency and high-order harmonic frequencies to treat the nonlinear composites. For nonlinear composite media with a low concentrations of spherical inclusions, we give the formulae of the nonlinear effective AC susceptibility at the third harmonic frequency.
文摘alculations of the nonlinear second-order optical susceptlbilities(β_(ijk))for sub- stituted tl1iophene derivative;with quinoidlike conformation are reported.These systetems possess small dipole moment;and large differences between dipole mo- ments of ground and first-excited states.Geometry optimizations of the molecules investigated were carried out using AM 1 method.The calculations were performed using INDO/CI method comboned with a sum-over-states expression for β_(jik). The calculated results sbw that the second-order susceptibility is a function of the na- ture and location of substituents and is larger for disubstituted molecules than monosubstituted molecules. Bipolymeric thiophenemetmne with NH_2/NO_2 groups was calctilated to have a β_μof 79. 920 × 10￣(-30) esu. It was found that the NH_2 and NO_2 groups in above disubstituted molecules are pull-pull groups in ground states,but are usual push-pull groups in the first excited states.
文摘A detailed analysis of the magnetic response of field-cooled type-I superconducting hollow cylinders shows that the so-called “paramagnetic Meissner effect” can take place in opportunely devised multiply connected superconductors. Adopting simple circuital analogs of the latter superconducting systems, the magnetic susceptibility of micro-cylinders with one or two holes is studied by means of energy considerations.
基金financially supported by the Vice President Officefor Research and Dean of School of Graduate Studies and Aklilu Lemma Institute of Pathobiology(grant No.RDP/PY-014/09)
文摘Objective:To evaluate the efficacy and side effects of praziquantel(PZQ) in the treatment of schistosomiasis in Ethiopia.Methods:In a cross-sectional study,stool specimens were collected from randomly selected 299 school children in Shesha Kekele Elementary School,Wondo Genet, Southern Ethiopia,in April 2010.Stool specimens were examined using a single Kato-Katz thick smear for Schistosoma mansoni(5.mansoni) ova.Children who were found positive for S.mansoni were treated with a single oral dose of PZQ at 40 mg/kg bw and interviewed for treatment-related symptoms 24 hours after drug administration.Four weeks post-treatment,stool specimens were collected from the same children and examined following the same procedure as in the pretreatment.Drug efficacy was determined based on cure and egg reduction rates.Results:Pretreatment prevalence of S.mansoni infection was 74.9%with geometric mean egg count of 268. The evaluated generic PZQ produced an overall cure rate of 73.6%(P<0.000 1,OR:8.33,CI:5.3-13.1) and egg reduction rate of 68.2%(P=0.03,F=0.64).The cure rate showed significant association with age(x^2=H,P=0.004),the highest rate being observed in the 15-22 age group.83%of S. mansoni infected children showed various treatment-related symptoms,the most frerjiient being headache,nausea,and abdominal pain.These symptoms were associated with age(P<0.001) and pre-treatment intensity of infection(P<0.05).Conclusions:The present observations revealed relatively lower cure and egg reduction rates of the PZQ evaluated as compared to previous reports for other PZQ brands in Ethiopia.Hence,in depth studies are recommended to clarify whether the present relatively lower cure rate is the actual cure rate of the praziquantel evaluated,treatment failure,or reduced susceptibility of the parasite.Treatment-related side effects observed were transient and tolerable.
基金Project supported by the National Natural Science Foundation of China(51176050)China Postdoctoral Science Foundation(2013M542274)
文摘The large disc LaFe11.6Si1.4 alloy, which was prepared by medium-frequency induction furnace, was annealed at 1503 K for different time. The main phases were 1：13 phase in the edge parts of the large discs alloy; the impurity phases included α-Fe phase, LaFeSi phase, and even very small amount of La5Si3 phase. The amounts of impurity phases reduced with increasing in annealing time. The magnetic properties in the edge parts of the large discs LaFe11.6Si1.4 alloy were investigated. The magnetic susceptibility had an abrupt change at Curie temperature（TC） as the magnetization in M-T curves. The alloys had almost the same TC（191 K）, the magnetocaloric effect（MCE） and relative cooling power（RCP） increased with increasing in annealing time. In addition, for the same alloy, the magnetic hysteresis decreased with the increase in temperature.
