Lattice dynamics properties of chalcopyrite ZnSnP_2:Density-functional calculations by using a linear response theory

We present a first-principles study of the structural,dielectric,and lattice dynamical properties for chalcopyrite semiconductor ZnSnP2.The structural properties are calculated using a plane-wave pseudopotential method of densityfunctional theory.A linear response theory is used to derive Born effective charge tensors for each atom,dielectric constants in low and high frequency limits,and phonon frequencies.We calculate all zone-center phonon modes,identify Raman and infrared active modes,and report LO-TO splitting of the infrared modes.The results show an excellent agreement with experiment and propose several predictive behaviors.

Dynamic electron transport theory for multiprobe mesoscopic structures

Using the linear response theory and random phase approximation, we develop a general dynamic electron transport theory for multiprobe mesoscopic structures in an arbitrarily time-dependent external field. In this case, the responses of the dynamic current, charge and internal potential to the external fields can be determined self-consistently. Without loss of generality, charge （current） conservation and gauge invariance under a potential shift are satisfied. As an example, we employ a quantum wire with a single barrier to discuss the response of the internal potential.

The Transition of the International System: From the Perspective of the Theory of Responsibility

The international system refers to the whole of the interacting and stable relationship formed by actors of

Discussion on Nida's Translation Theory and Applications Through MuLAN

Eugene Nida's Translation Theory has a profound influence both on global and Chinese translation circle.Although this theory is widely used,it also become a controversial topic in a certain extent.Through the movie MuLAN and some applications in useful areas to discuss whether Nida's Translation Theory is still applicable within translating field.

Ion Dynamics in Concentrated Electrolyte Solutions:Relating Equilibrium Fluctuations of the Ions to Transport Properties in Battery Cells

In recent years,the interest in the development of highly concentrated electrolyte solutions for battery applications has increased enormously.Such electrolyte solutions are typically characterized by a low flammability,a high thermal and electrochemical stability and by the formation of a stable solid electrolyte interphase(SEI)in contact to electrode materials.However,the classification of concentrated electrolyte solutions in terms of the classical scheme"strong"or"weak"has been controversially discussed in the literature.In this paper,a comprehensive theoretical framework is presented for a more general classification,which is based on a comparison of charge transport and mass transport.By combining the Onsager transport formalism with linear response theory,center-of-mass fluctuations and collective translational dipole fluctuations of the ions in equilibrium are related to transport properties in a lithium-ion battery cell,namely mass transport,charge transport and Li^(+)transport under anion-blocking conditions.The relevance of the classification approach is substantiated by showing that i)it is straightforward to classify highly concentrated electrolytes and that ii)both fast charge transport and fast mass transport are indispensable for achieving fast Li^(+)transport under anion-blocking conditions.

Evaluation of latent links between irritable bowel syndrome and sleep quality

AIM:To examine the links between quality of sleep and the severity of intestinal symptoms in irritable bow-el syndrome(IBS).METHODS:One hundred and forty-two outpatients(110female,32 male)who met the Rome Ⅲ criteria for IBS with no psychiatric comorbidity were consecutively en-rolled in this study.Data on age,body mass index(BMI),and a set of life-habit variables were recorded,and IBS symptoms and sleep quality were evaluated using the questionnaires IBS Symptom Severity Score(IBS-SSS)and Pittsburgh Sleep Quality Index(PSQI).The associa-tion between severity of IBS and sleep disturbances was evaluated by comparing the global IBS-SSS and PSQI score(Pearson's correlation and Fisher's exact test)and then analyzing the individual items of the IBS-SSS and PSQI questionnaires by a unitary bowel-sleep model based on item response theory(IRT).RESULTS:IBS-SSS ranged from mild to severe(120-470).The global PSQI score ranged from 1 to 17(median 5),and 60 patients were found to be poor sleepers(PSQI>5).The correlation between the global IBS-SSS and PSQI score indicated a weak association(r=0.2 and 95% CI:-0.03 to 0.35,P<0.05),which becomes stronger using our unitary model.Indeed,the IBS and sleep disturbances severities,estimated as latent variables,resulted significantly high intra-subject cor-relation(posterior mean of r=0.45 and 95% CI:0.17 to 0.70,P<0.05).Moreover,the correlations between patient features(age,sex,BMI,daily coffee and alcohol intake)and IBS and sleep disturbances were also ana-lyzed through our unitary model.Age was a signif icant regressor,with patients≤50 years old showing more severe bowel disturbances(posterior mean=-0.38,P<0.05)and less severe sleep disturbances(posterior mean=0.49,P<0.05)than older patients.Higher daily coffee intake was correlated with a lower sever-ity of bowel disturbances(posterior mean=-0.31,P<0.05).Sex(female)and daily alcohol intake(modest)were correlated with less severe sleep disturbances.CONCLUSION:The unitary bowel-sleep model based on IRT revealed a strong positive correlation between the severity of IBS symptoms and sleep disturbances.

Theoretical Studies on One-photon and Two-photon Absorption Properties of Pyrene-core Derivatives

The analytic response theory at density functional theory level is applied to investigate onephoton and two-photon absorption properties of a series of recently synthesized pyrene-core derivatives. The theoretical results show that there are a few charge-transfer states for each compound in the lower energy region. The one-photon absorption properties of the five investigated compounds are highly consistent with those given by experimental measurements. The two-photon absorption intensities of the compounds are greatly enhanced with the increments of the molecular sizes, in which the two-photon absorption cross section of the four-branched compound is about 5.6 times of that of the mono-branched molecule. Fhrthermore, it is shown that the two-photon absorption properties are sensitive to the geometrical arrangements.

Reducing Item Exposure in Computerized Adaptive Testing Systems Using Automatic Item Generation

This paper studies the technics of reducing item exposure by utilizing automatic item generation methods. Known test item calibration method uses item parameter estimation with the statistical data, collected during examinees prior testing. Disadvantage of the mentioned item calibration method is the item exposure; when test items become familiar to the examinees. To reduce the item exposure, automatic item generation method is used, where item models are being constructed based on already calibrated test items without losing already estimated item parameters. A technic of item model extraction method from the already calibrated and therefore exposed test items described, which can be used by the test item development specialists to integrate automatic item generation principles with the existing testing applications.

Solvent effects on structure and optical properties of a D-π-A azobenzene dye

Time-dependent hybrid density functional theory in combination with Onsager reaction field model and super-molecular model has been applied to study solvent effects on the geometrical and electronic structures, as well as one/two-photon absorption properties, of 4-（N-（2-hydroxyethyl）-N-methyl）-amino-4＇-nitroazobenzene. It is found that the short-range interaction has a large effect on the electronic structure of the solute molecule, namely, large red-shift of the maximum one-photon absorption is induced by hydrogen bonding. The solute molecule has a large two-photon absorption cross section, which is enhanced by the solvent effect. The computational results are in good agreement with measurements.

Protonation Effect on One- and Two-photon Absorption Property of a Newly Synthesized Octupolar Chromophore

The protonation effects on one- and two-photon absorption properties of an octupolar molecule TA with 1,3,5-triazine core and pyrrole electron-donating end-groups have been studied at hybrid density functional theory level. A computational scheme is developed to simulate a proton attached to an atom. The numerical results show that large changes in both one- and two-photon absorption properties are observed when the compound is transformed from neutral to threefold protonated states. When the compound is protonated, more charge transfer states appear and the absorption band has a red-shift. Furthermore, the two-photon absorption cross-section is largely enhanced. The theoretical calculations demonstrate the protonation effect on promoting the intramolecular charge transfer strength. The results present qualitative agreement with the experimental observations. A two-photon absorption switch with the compound TA based on the protonation effect is proposed.

Responsive mechanism of 2-(2'-hydroxyphenyl)benzoxazole-based two-photon fluorescent probes for zinc and hydroxide ions

Response theory is used to investigate one- and two-photon absorption（TPA） as well as the emission properties of a series of potential zinc ion and pH sensitive materials containing 2-（2＇-hydroxyphenyl）benzoxazole（HPBO） end groups.Special emphasis is placed on the evolution of their optical properties upon combining with zinc ions or deprotonation.Our calculated results indicate that upon combining with zinc ions or deprotonation,these HPBO derivatives show drastic changes in their one-photon absorption（OPA）,emission,and TPA properties.Moreover,the mechanisms of the probes are analyzed and found to be an intramolecular charge transfer.These compounds are thus proved to be excellent candidates for two-photon fluorescent zinc and pH probes.

Surface plasmon-polaritons on ultrathin metal films

We discuss the surface plasmon-polaritons used for ultrathin metal films with the aid of linear response theory and make comparisons with the known result given by Economou E N. In this paper we consider transverse electromagnetic fields and assume that the electromagnetic field in the linear response formula is the induced field due to the current of the electrons. It satisfies the Maxwell equation and thus we replace the current （charge） term in the Maxwell equation with the linear response expectation value. Finally, taking the external field to be zero, we obtain the dispersion relation of the surface plasmons from the eigenvalue equation. In addition, the charge-density and current-density in the z direction on the surface of ultrathin metal films are also calculated. The results may be helpful to the fundamental understanding of the complex phenomenon of surface plasmon-polaritons.

Particles inside electrolytes with ion-specific interactions, their effective charge distributions, and effective interactions

In this work, we explore the statistical physics of colloidal particles that interact with electrolytes via ion-specific interactions. Firstly we study particles interacting weakly with electrolyte using linear response theory. We find that the mean potential around a particle is linearly determined by the effective charge distribution of the particle, which depends both on the bare charge distribution and on ion-specific interactions. We also discuss the effective interaction between two such particles and show that, in the far field regime, it is bilinear in the effective charge distributions of two particles. We subsequently generalize the above results to the more complicated case where particles interact strongly with the electrolyte.Our results indicate that in order to understand the statistical physics of non-dilute electrolytes, both ion-specific interactions and ionic correlations have to be addressed in a single unified and consistent framework.

The aggregation effects on the two-photon absorption properties of para-nitroaniline polymers by hydrogen-bond interactions

This paper has theoretically designed a series of aggregate polymers on the basis of several para-nitroaniline monomers by hydrogen-bond interactions. At the level of time-dependent hybrid density functional theory, it has optimized their geometrical structures and studied their two-photon absorption （TPA） properties by using analytical response theory. The calculated results exhibit that the aggregation effects not only bring out the conaiderable red shift of the excited energies but also greatly enhance the TPA intensities of the aggregate polymers in comparison with the para-nitroaniline monomer. The aggregate configurations also have an important influence on the TPA abilities of the polymers; the trimer has the largest TPA cross section. The electron transitions between the molecular orbits involving the strong TPA excitations of the trimer are depicted to illuminate the relationship between the intermolecular charge transfer and the TPA property.

Broadband strong optical dichroism in topological Dirac semimetals with Fermi velocity anisotropy

Prototypical three-dimensional(3D)topological Dirac semimetals(DSMs),such as Cd3As2 and Na3Bi,contain electrons that obey a linear momentum-energy dispersion with different Fermi velocities along the three orthogonal momentum dimensions.Despite being extensively studied in recent years,the inherent Fermi velocity anisotropy has often been neglected in the theoretical and numerical studies of 3D DSMs.Although this omission does not qualitatively alter the physics of light-driven massless quasiparticles in 3D DSMs,it does quantitatively change the optical coefficients which can lead to nontrivial implications in terms of nanophotonics and plasmonics applications.Here we study the linear optical response of 3D DSMs for general Fermi velocity values along each direction.Although the signature conductivity-frequency scaling,σ(ω)∝ω,of 3D Dirac fermion is well-protected from the Fermi velocity anisotropy,the linear optical response exhibits strong linear dichroism as captured by the universal extinction ratio scaling law,Λi j=(vi/v j)^2(where i=j denotes the three spatial coordinates x,y,z,and vi is the i-direction Fermi velocity),which is independent of frequency,temperature,doping,and carrier scattering lifetime.For Cd3As2 and Na3Bi3,an exceptionally strong extinction ratio larger than 15 and covering a broad terahertz window is revealed.Our findings shed new light on the role of Fermi velocity anisotropy in the optical response of Dirac semimetals and open up novel polarization-sensitive functionalities,such as photodetection and light modulation.

One- and two-photon absorption properties of two metalloporphyrin complexes

The linear and nonlinear optical properties of two metalloporphyrin complexes formed by the complementary coordination of central zinc or magnesium ions to the ligand 5, 10, 15-tri-（p-tolyl）-20-phenylethynylporphyrin are theo- retically investigated by using the analytic response theory at the density functional theory level. The results indicate that the studied complexes present more symmetric geometry structures than the ligand. The charge-transfer states of the two complexes in the lower energy region are all almost degenerate but those of the ligand are well separated. The ratio of the two-photon absorption cross sections of the ligand, zinc-porphyrin and magnesium-porphyrin com- plexes is 1.0：1.5：1.8, demonstrating that the two-photon absorption capability can be greatly increased when the ligand is coordinated with a metal ion. Moreover, several physical micro-mechanisms including electron transitions and in- tramolecular charge-transfer processes are discussed to explore the differences in optical property between the ligand and two complexes.

The theoretical studies on the two-photon absorption properties of symmetric l,4-bis{2-[4-(2-aryl)phenyl]vinyl}-2,5-bisdialkoxybenzenes

On the level of the time-dependent hybrid density functional theory, the one- and two-photon absorption properties of a series of symmetric 4-bis{2-[4-（2-aryl） phenyl]vinyl）-2,5-bisdialkoxybenzenes are studied respectively utilizing the analytic response theory and the few-state model methods. The calculated results show that the planarity of the geometrical structure plays a great role in enhancing the linear and nonlinear optical abilities of the molecule. However the effect of the length of the chain linked to the π-centre on the optical property is very little. For the investigated compounds, the A-π-A type charge-transfer molecules display more superior one- and two-photon absorption characteristics than the D-π-D type ones. Furthermore, the two-photon absorption results by use of few-state model are generally consistent with those by analytic response theory, demonstrating the reliability of the few-state model for evaluating the two-photon absorption cross section. The numerical simulations are in good agreement in tendency with the available experimental measurements.

Atom Response Theory of Nonlinear Optical Responses and Its Applications

Second-order nonlinear optical(NLO)crystalline materials are fundamentally and technologically important for their ability to double or triple the frequency of lasers.This article provides a brief review of the atom response theory(ART)of NLO responses recently developed on the basis of the partial response functional method.The ART analysis enables one to quantitatively evaluate the contributions of individual constituent atoms to the second harmonic generation(SHG)response of a NLO crystal material on the basis of first principles DFT calculations.The general partitioning principles developed in our recent work provide the conceptual foundation for determining the functional motifs of SHG responses.In this mini review we will focus on the concepts and principles as well as on applications with examples.Some practically important empirical rules resulting from the ART studies will also be reviewed.

Media Ethics as Key to Sound Professionalism in Nigerian Journalism Practice

This paper examines the implications of ethics as key to sound professionalism in Nigerian journalism. The paper sets out to assess how ethics affect the standard of journalism practice in the country, using media practitioners in Rivers State, Nigeria as case study. The population of study consisted of the 300 registered journalists in Rivers State of Nigeria, including the editors and managers. The survey research method was used while the questionnaire was used as the primary instrument for data gathering. It was revealed that despite the importance of ethics to journalism practice, journalists＇ adherences to the ethical codes were low. The study also revealed that journalists most times go against the ethics of the profession due to sycophancy, security reasons, desperation, greed, ethical dilemmas, and ignorance of the code of ethics. Based on the timings of the study, it was recommended that media establishments should liaise with the Nigerian Union of Journalist （NUJ） to ensure that only trained journalists are employed to work as journalists. Again the NUJ, it should institute standing disciplinary committee to discipline erring journalists both at the State and National levels. The Ethics Committee of the Nigeria Union of Journalists should regularly review the ethical conducts of journalists and encourage them to adhere to their code of practice

Extreme value of wind-excited response considering influence of bandwidth

This paper addresses the peak factors of wind- excited responses including alongwind, acrosswind tall building responses and vortex-induced vibration considering the bandwidth parameter. The influence of bandwidth parameter on the peak factor is investigated using advanced upcrossing theory taking the bandwidth influence into account. Results show that Davenport＇s formula without consideration of bandwidth parameter servers well in general. However, the advanced upcrossing theory leads to a better prediction of the peak factor of wind-induced response of very lightly damped buildings.