Moment Properties Research Articles

The Role of the Various Solvent Polarities on Piperine Reactivity and Stability

Piperine is a natural cytotoxic agent aware of various therapeutic acts. The aim of this study is to look into the effects of solvent polarity on solvent-free energy, dipole moment, polarizability, and hyper-polarizability of the first order, as well as various molecular properties including chemical hardness and softness, chemical potential, electronegativity, and electrophilicity index, in order to gain a better understanding of its reactivity and stability. The Becke, 3-parameter, Lee-Yang-Parr (B3LYP) level of theory with the cc-pVDZ basis set was used to perform all forms of calculations in both the gas phase and in solution. The Solvation Model on Density (SMD) was used to measure the solvation-free energy, dipole moment, and molecular properties of five solvent systems: water, DMSO, ethanol, cyclohexane, and heptane. As the dielectric constant was reduced, the solving energies gradually decreased, i.e. free energy decreased with declining solvent polarity. Piperine's dipole moment has been found to increase when transitioning from non-polar to polar solvents. The dipole moment of piperine was greater than that of the gas phase in various solvents. PPN's dipole moment and first order hyper-polarizability gradually increased as the solvent polarity increased, while its polarizability decreased. In addition, the hardness, chemical potential and electrophilicity index were decreased from non-polar to polar solvent, but with the rise in solvent polarity for the PPN molecule, softness and electronegativity were increased. The determined free energy solvation, dipole moment, polarizability, hyper-polarizability of the first order, and molecular properties identified in this research may contribute to an understanding of the stability and reactivity of piperine in specific solvent systems.

The Moment Properties of Order, Reversed Order and Upper Record Statistics for the Power Ailamujia Distribution

The power Ailamujia distribution has been successfully developed in statistics, both theoretically and practically, performing well in the fitting of various types of data. This paper investigates the moment properties of the associated order, reversed order and upper record statistics, which are indeed unexplored aspects of this distribution. In particular, the exact expressions for the single moments of the order and reversed order statistics are provided. Some recurrence relationships for both single and product moments for the order and upper record statistics are proved. For additional goals, certain joint distributions are also given.

Quantum chemical studies on structural, spectroscopic, nonlinear optical, and thermodynamic properties of the 1,2,4-triazole compound

AbstractIn this study, the structure of 4-[4-(diethylamino)-benzylideneamino]-5-benzyl-2H-1,2,4-triazol-3(4H)-one (DBT) was examined through spectroscopic and theoretical analyses. In this respect, the geometrical, vibrational frequency,1H and13C-nuclear magnetic resonance (NMR) chemical shifts, thermodynamic, hyperpolarizability, and electronic properties including the highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) energies of DBT as a potential non-linear optical (NLO) material were investigated using density functional theory at the B3LYP level with the 6-311G basis set.1H and13C-NMR chemical shifts of DBT with the gauge-invariant atomic orbital and continuous set of gauge transformation methods (in the solvents) were estimated, and the computed chemical shift values displayed excellent alignment with observed ones. Time-dependent density-functional theory (TD-DFT) calculations with the integral equation formalism polarizable continuum model within various solvents and gas phases in the ground state were used to evaluate UV-vis absorption and fluorescence emission wavelengths. Thermodynamic parameters including enthalpy, heat capacity, and entropy for DBT were also calculated at various temperatures. Moreover, calculations of the NLO were carried out to obtain the title compound’s electric dipole moment and polarizability properties. To illustrate the effect of the theoretical method on the spectroscopic and structural properties of DBT, experimental data of structural and spectroscopic parameters were used. The correlational analysis results were observed to indicate a strong relationship between the experimental and theoretical results.

Impact of Solvent Polarity on the molecular properties of Dimetridazole

Recently molecular activity of dimetridazole (DMZ) gained interested due to medical applications. In this study, a computational investigation of the solvent impact on solvation free energy, dipole moments, polarizability, hyper-polarizability and characteristic atomic properties; hardness and softness quality, chemical potential, electronegativity and electrophilicity have been accounted for DMZ. All forms of the calculation for both gas phase and solution phase used Becke 3-Parameter of Lee-Yang parr (B3LYP) theory with a 631++G basis set. Using the Solvation Model on Density (SMD), the effect of solvent polarity on solvation free energy, dipole moment, polarizability, hyper-polarizability and molecular properties were measured. The dipole moment of the DMZ was lower value in a gas phase comparative with solution phase. Furthermore, the electronegativity and chemical potential were increased from non-polar to polar solvents, while electrophilicity index was decreased. However, in case of chemical hardness & softness, the opposite relationship has been found. The results of this study contribute to an understanding of the molecular activity of DMZ, and stimulate its activity in solution phase. Keywords: Dimetrizole, Solvation model, Dipole moment, Solvent-free energy, Molecule polarizability.

Enantio-detection via cavity-assisted three-photon processes.

We propose a method for enantio-detection of chiral molecules based on a cavity-molecule system, where the left- and right-handed molecules are coupled with a cavity and two classical light fields to form cyclic three-level models. Via the cavity-assisted three-photon processes based on the cyclic three-level model, photons are generated continuously in the cavity even in the absence of external driving to the cavity. However, the photonic fields generated from the three-photon processes of left- and right-handed molecules differ with the phase difference π according to the inherent properties of electric-dipole transition moments of enantiomers. This provides a potential way to detect the enantiomeric excess of chiral mixture by monitoring the output field of the cavity.

Moment properties of Markov chain-based claim processes

Aggregate discrete random variables (rvs) may have several possible scenarios: the number of rvs is either deterministic or stochastic; sequence of rvs may be (in)dependent and (not) identically distributed. In this paper, we investigate claim process as deterministic aggregate of dependent discrete rvs constructed from two-states and three-states Markov chain (MC) processes. In particular, the moment properties of such process are explored. We also observe persistence (index) property and its relationship with other properties of Markov chain with absorbing states. Moreover, we show some features of relationship between persistence index and correlation coefficient. A simulation study is carried out to illustrate such property and relationship.

Hysteretic dipolar and quadrupolar properties of the spin-1 Blume–Emery–Griffiths model under pair approximation

As a continuation of previously published work [A. Erdinç and M. Keskin, Int. J. Mod. Phys. B 18, 1603 (2004), doi:10.1142/S0217979204024823] the hysteretic properties of magnetization ([Formula: see text]) and quadrupolar moment ([Formula: see text] have been investigated for the spin-1 Blume–Emery–Griffiths model using pair approximation. The magnetic field ([Formula: see text]) dependence of [Formula: see text] is produced for different values of the lattice coordination number ([Formula: see text]), biquadratic interaction ([Formula: see text]) and single-ion anisotropy ([Formula: see text]). The ([Formula: see text]) loops show different and novelty properties when [Formula: see text]. We also observed the hysteresis cycles in the ([Formula: see text], ([Formula: see text] and ([Formula: see text]) planes. These curves strongly depend on biquadratic interaction [Formula: see text]. Our results are found to be in good agreement with the other theoretical findings.

Multifunctional fluorinated ammonium salt for high-performance all-inorganic CsPbI2Br perovskite solar cells with efficiency of 16.29%

All-inorganic CsPbI2Br material has attracted considerable attention due to its good balance between phase stability and absorption capacity. However, the power conversion efficiency (PCE) and device stability of CsPbI2Br-based perovskite solar cells (PSCs) still lag far behind those of their counterparts, mainly deriving from the notoriously poor moisture stability under humid environment and large serious charge recombination. Herein, a typical phenethylammonium chlorine (PEACl) and its fluorinated derivative 4-fluoro-phenethylammonium chlorine (F-PEACl) are individually incorporated to modify the surface of CsPbI2Br film to ameliorate the above issues. Benefiting from the comprehensive passivation effect of ammonium halogen, the trap states of treated CsPbI2Br are vastly suppressed. In particular, fluorination significantly increased the dipole moment and hydrophobic property of F-PEACl. Thus, the present CsPbI2Br PSC achieves a champion PCE of 16.29% with high open-circuit voltage of 1.272 V, while the reference device and PEACl-treated device yield PCEs of 14.30% and 15.64%, respectively. More importantly, the PSC with F-PEACl capping layer retains 87.2% of its initial PCE after 1000 h storage under 20% RH ambient without encapsulation. Our results reveal the underlying mechanism of performance improvement by surface passivation strategy and provide an effective approach to further boost the CsPbI2Br PSC efficiency and stability.

A Study on Moments of Dual Generalized Order Statistics from Exponentiated Generalized Class of Distributions

In this paper, relations between moments of dual generalized order statistics from an exponentiated generalized class of distributions, given by Cardeiro (2013) are studied. Some particular cases of dual generalized order statistics and examples based on it are discussed. The characterization of given distribution based on moment properties is also presented.

Miejsca, chwile, przedmioty i ludzie (część II)

In the text I analyze the flea market in Świdnica (Poland): items from different places and times present there. I argue that the meeting of these objects is at the same time indirectly the meeting of these different places and moments in one moment and place. I wonder how is this possible? I refer to three concepts: the global cultural ecumen, the palimpsest and the postulate of treating local and global as closely related. I come to the conclusion that these concepts should be supplemented with ontic properties of place, space, moments and time. Continuity is one of the most important here. The continuity of space and time is a necessary condition for the ecumenical character of culture, the close relationship between local and global, and the palimpsest character of the present day.

Structural and vibrational spectral investigation on the identification of Non-Linear Optical properties and wave function analyses (electrostatic potential, electron localisation function, localised orbital locator) of 3-Ethoxy Salicilaldehyde

ABSTRACT In the present study, 3-Ethoxy Salicilaldehyde (3ES) was investigated in terms of structural, vibrational spectroscopic and theoretical analyses. All the theoretical calculations were done with the density functional theory method. The natural bond orbital analysis had been done to understand the probable charge transfer interaction in the molecule. The Frontier molecular orbitlas’ molecular electrostatic potential surface has been plotted and the reactive sites of electrophilic and nucleophilic attacks of the molecule have been estimated. The possible vibrations were identified and analysed using the Vibrational Energy Distribution Analysis 4 (VEDA 4) program and Vibrational spectrum. The Fukui function analysis was also used to predict the reactive sites of electrophilic and nucleophilic attacks for the 3ES molecule. Based on electron density, weak interactions of the studied molecules were identified with the aid of RDG analysis. The dipole moment, polarisaility, first-order hyperpolarisability (α 0) and related properties (β, α 0 and Δα) and second-order hyperpolarisabilties were calculated for the identification of non-linear optical activity of the molecule. The second harmonic generation study also has been done for understanding the non-linear optical activity of the molecule.

A note on the stability of multivariate non-linear time series with an application to time series of counts

We introduce a simple criterion for studying stationarity and moments properties of some multivariate Markovian autoregressive processes, under a contracting mapping assumption. We apply our results to the Poisson INGARCH model and to one of its multivariate extension recently introduced in the literature. In particular, we obtain optimal stationarity conditions and existence of some exponential moments.

Moment properties of lower record values from generalized inverse Weibull distribution and characterization

In this paper, the exact expressions as well as recurrence relations for single and product moments of the generalized lower record values from generalized inverse Weibull distribution are obtained. Further, the characterization of the given distribution is carried out through recurrence relations and conditional moment.

New non-fullerene electron acceptors-based on quinoxaline derivatives for organic photovoltaic cells: DFT computational study

In this work, we develop a new non-fullerene electron acceptor for organic photovoltaic cells. Precisely, we present a computational study of new engineered molecules-based quinoxaline derivative (R, C1-C5) using density functional theory (DFT) and time dependent-density functional theory (TD-DFT). In particular, we investigate the frontier molecular orbitals (FMOs), density of states (DOS) analysis, molecular electrostatic potential (MEP), global reactivity descriptors, dipole moment, charge mobilities and optical properties of designed compounds. Among others, we find that all engineered compounds involve a small band gap, good optical aspects and charge mobilities. Considering PTB7-Th as an electron donor, we study the photovoltaic properties of novel acceptors. Consequently, designed compounds provide a strong charge conduction ability and effective electron transport from the donor to the acceptor. The obtained results encourage to test experimentally such molecules which could enhance the performance of non-fullerene organic photovoltaic cells.

A Weighted Poisson Distribution for Underdispersed Count Data

In this paper, we present a new weighted Poisson distribution for modeling underdispersed count data. Weighted Poisson distribution occurs naturally in contexts where the probability that a particular observation of Poisson variable enters the sample gets multiplied by some non-negative weight function. Suppose a realization y of Y a Poisson random variable enters the investigator’s record with probability proportional to w(y): Clearly, the recorded y is not an observation on Y, but on the random variable Yw, which is said to be the weighted version of Y. This distribution a two-parameter is from the exponential family, it includes and generalizes the Poisson distribution by weighting. It is a discrete distribution that is more flexible than other weighted Poisson distributions that have been proposed for modeling underdispersed count data, for example, the extended Poisson distribution (Dimitrov and Kolev, 2000). We present some moment properties and we estimate its parameters. One classical example is considered to compare the fits of this new distribution with the extended Poisson distribution.

Stieltjes moment properties and continued fractions from combinatorial triangles

Many combinatorial numbers can be placed in the following generalized triangular array [Tn,k]n,k≥0 satisfying the recurrence relation:Tn,k=λ(a0n+a1k+a2)Tn−1,k+(b0n+b1k+b2)Tn−1,k−1+d(da1−b1)λ(n−k+1)Tn−1,k−2 with T0,0=1 and Tn,k=0 unless 0≤k≤n for suitable a0,a1,a2,b0,b1,b2,d and λ. For n≥0, denote by Tn(q) the generating function of the n-th row. In this paper, we develop various criteria for x-Stieltjes moment property and 3-x-log-convexity of Tn(q) based on the Jacobi continued fraction expression of ∑n≥0Tn(q)tn, where x is a set of indeterminates consisting of q and those parameters occurring in the recurrence relation. With the help of a criterion of Wang and Zhu (2016) [36], we show that the corresponding linear transformation of Tn,k preserves Stieltjes moment properties of sequences. Finally, we present some related examples including factorial numbers, Whitney numbers, Stirling permutations, minimax trees and peak statistics.

Study of a unit power-logarithmic distribution

This article proposes a new unit distribution based on the power-logarithmic scheme. The corresponding cumulative distribution function is defined by a special ratio of power and logarithmic functions that is dependent on one parameter. We show that this function benefits from great flexibility characterized by a large selection of convex and concave shapes. The other key functions are determined and studied. In particular, we show that the probability density function may take on different decreasing or U shapes, and the hazard rate function has a wide panel of U shapes. These functional capabilities are rare for a one-parameter unit distribution. In addition, we prove certain stochastic order results, provide the expression of the quantile function via the Lambert function, some interesting distributional results, and give simple expressions for the ordinary moments, mean, variance, skewness, kurtosis, moment generating function and incomplete moments. Subsequently, a basic statistical approach is described, to show how the new distribution can be applied in a data analysis scenario. Finally, complementary mathematical findings are presented, yielding new integrals linked to the Euler constant via some well-known moments properties.

Graph Evaluation and Review Technique for Emergency Logistics Distribution in Complex Environment

Emergency logistics is one of the important measures to solve the unconventional sudden disaster. The research on the distribution design of emergency logistics project has an important supporting role for the whole emergency rescue system. Therefore, it is necessary to analyze and plan the emergency logistics project scientifically in order to better serve the emergency rescue system. In view of the defect that the current emergency logistics model cannot completely describe the whole emergency logistics process, this paper proposes a new emergency logistics distribution model by using GERT random network. From the perspective of system, this model fully considers the possible situation in the process of emergency material transportation and puts forward the corresponding countermeasures, so as to improve the transportation efficiency of rescue materials in the actual disaster relief activities to speed up disaster relief. Based on the properties of moment generating function and the calculation method of Mason formula, this paper fully considers the success probability, risk probability, delivery time, and other factors of the distribution route and puts forward the transshipment scheme of each logistics site to the disaster sites. After that, the effectiveness of GERT stochastic network in the process of emergency distribution is verified by an example of a logistics distribution route, which provides decision-making basis for relevant departments. Compared with the literature, this paper uses GERT network model to intuitively and clearly express the overall process of emergency material distribution, breaks through the thinking mode of simply choosing the distribution path in the distribution process, combines with the dynamic changes of the distribution environment, and comprehensively considers the timeliness and traffic capacity of emergency material distribution in sudden disasters, so as to provide reference for emergency management in complex and random situations for decision-making reference.

On a Stirling–Whitney–Riordan triangle

Based on the Stirling triangle of the second kind, the Whitney triangle of the second kind and one triangle of Riordan, we study a Stirling–Whitney–Riordan triangle \([T_{n,k}]_{n,k}\) satisfying the recurrence relation: $$\begin{aligned} T_{n,k}= & {} (b_1k+b_2)T_{n-1,k-1}+[(2\lambda b_1+a_1)k+a_2+\lambda ( b_1+b_2)] T_{n-1,k}+\\&\lambda (a_1+\lambda b_1)(k+1)T_{n-1,k+1}, \end{aligned}$$where initial conditions \(T_{n,k}=0\) unless \(0\le k\le n\) and \(T_{0,0}=1\). We prove that the Stirling–Whitney–Riordan triangle \([T_{n,k}]_{n,k}\) is \(\mathbf{x} \)-totally positive with \(\mathbf{x} =(a_1,a_2,b_1,b_2,\lambda )\). We show that the row-generating function \(T_n(q)\) has only real zeros and the Turán-type polynomial \(T_{n+1}(q)T_{n-1}(q)-T^2_n(q)\) is stable. We also present explicit formulae for \(T_{n,k}\) and the exponential generating function of \(T_n(q)\) and give a Jacobi continued fraction expansion for the ordinary generating function of \(T_n(q)\). Furthermore, we get the \(\mathbf{x} \)-Stieltjes moment property and 3-\(\mathbf{x} \)-log-convexity of \(T_n(q)\) and show that the triangular convolution \(z_n=\sum _{i=0}^nT_{n,i}x_iy_{n-i}\) preserves Stieltjes moment property of sequences. Finally, for the first column \((T_{n,0})_{n\ge 0}\), we derive some properties similar to those of \((T_n(q))_{n\ge 0}.\)

Study on the growth behavior and photoelectron spectroscopy of neodymium-doped silicon nanoclusters NdSin0/- (n = 8-20) with a double-hybrid density functional theory.

Structural evolution, magnetic moment, and thermochemical and spectral properties of NdSin0/- (n = 8-20) nanoclusters were studied. Optimized structures for NdSin demonstrated that the configuration with quintet ground state prefers Nd-substituted for a Si of the most stable Sin + 1 (n = 8-11) structure to Nd-linked configuration with Si9 tricapped trigonal prism subcluster (n = 12-19). Finally, the configuration prefers to Nd-encapsulated into Si cage framework (n = 20). For anion, the evolution at the quartet state prefers Nd-linked structure for n = 8-19 (excluded 9), and prefers Nd-encapsulated structure of n = 20. The spectral information including electron affinity, vertical detachment energy, and simulated photoelectron spectroscopy were also observed. The 4f electrons of Nd atom in NdSin with n = 8-10 hardly participate in bonding, but take part in remaining neutral clusters and all anionic NdSin- clusters. The calculations of average bond energy, HOMO-LUMO gap, and chemical bonding analyses reveal that NdSi20- possesses perfect thermodynamic and ideal chemical stability, making it as the most appropriate constitutional units for novel multi-functional semiconductors.