Method For Direct Construction Research Articles

Research on the microscopic mechanism and model applicability differences of CH4 and CO2 adsorption based on molecular dynamics

To verify the accuracy and rationality of the molecular simulation model, the microscopic mechanism of gas adsorption was analyzed and clarified from a microscopic perspective. The effect of molecular models created by direct construction and supercell expansion on the adsorption capacities of CH4 and CO2 has been analyzed. Eight coal-based molecular configurations were created to simulate the isothermal adsorption process of CH4 and CO2 using various coal-based molecular configurations. Using physical experiments, the validity of different construction methods for coal-based molecular structures was verified. The direct construction method was chosen to simulate the effect of various coal-based molecular numbers on the adsorption capacity of CH4 and CO2. The results show that the adsorption capacity of CO2 on coal is greater than that of CH4. The isothermal adsorption curves of CH4 and CO2 in coal-based molecular systems constructed using different methods reveal that the adsorption of methane on coal molecules adheres to the Langmuir monolayer adsorption theory. The adsorption sites for methane increase with the rise in free volume. The structure directly constructed and the supercell expansion directly determines the amount of methane adsorbed by each coal based molecule. The adsorption constants of CH4 and CO2 on the supercell extended structure are more volatile than those on the directly constructed structure, and the structure constructed directly for different coal based molecules is better than the supercell extended structure. The simulation using the direct construction method shows that as the number of coal-based molecules in the molecular configuration increases, The isothermal adsorption quantities of CH4 and CO2 increase linearly. The molecular configuration is not affected by the number of anthracite molecules. Molecular configuration is not affected by the number of anthracite molecules. The rationality of model construction has no obvious relationship with the number of coal based molecules.

Desulfonation-associated direct amide bond formation between N-sulfonyl-1,2,3-triazoles with carboxylic acids

We have developed a highly N2-regioselective method for direct construction of amide bond from N-sulfonyl-1,2,3-triazoles and carboxylic acids in the presence of bases at 60 °C in air. The developed reaction provides the corresponding products with high yields (up to 90 %) and a broad substrate compatibility including aryl acids, heterocyclic acids, and alkyl acids. Mechanistic studies show that the reaction proceeds through a direct nucleophilic attack of N-sulfonyl-1,2,3-triazoles to carboxylate anions via a base- and water-involved synergistic desulfonation process. This work presents an unusual water-involved example for direct synthesis of amides utilizing readily available starting materials under mild conditions.

Controllable Synthesis of Cyclopenta[b]indolines via Photocatalytic Fluoroalkylative Radical Cyclization Cascade of Ynamides.

A de novo method for direct construction of cyclopenta[b]indolines via a photocatalytic fluoroalkylative radical cyclization cascade of ynamides has been established, which proceeds via a sequence of radical addition, 1,5-HAT, 5-endo-trig cyclization, intramolecular arylation, and oxidative deprotonation. This protocol allows for the controllable assembly of a tricyclic architecture with three contiguous stereocenters, showcasing its high efficiency, compatibility, and regio- and diastereoselectivity for accessing pharmacologically significant fluoroalkylated cyclopenta[b]indolines. It represents one of the very few examples of tetrafunctionalization of alkynes.

Multicomponent Reductive Coupling for Selective Access to Functional γ-Lactams by a Single-Atom Cobalt Catalyst.

Despite their significant importance to numerous fields, the difficulties in direct and diverse synthesis of α-hydroxy-γ-lactams pose substantial obstacles to their practical applications. Here, we designed a nitrogen and TiO2 co-doped graphitic carbon-supported material with atomically dispersed cobalt sites (CoSA-N/NC-TiO2), which was successfully applied as a multifunctional catalyst to establish a general method for direct construction of α-hydroxy-γ-lactams from cheap and abundant nitro(hetero)arenes, aldehydes, and H2O with alkynoates. The striking features of operational simplicity, broad substrate and functionality compatibility (>100 examples), high step and atom efficiency, good selectivity, and exceptional catalyst reusability highlight the practicality of this new catalytic transformation. Mechanistic studies reveal that the active CoN4 species and the dopants exhibit a synergistic effect on the formation of key acid-masked nitrones; their subsequent nucleophilic addition to the alkynoates followed by successive reduction, alkenyl hydration, and intramolecular ester ammonolysis delivers the desired products. In this work, the concept of reduction interruption leading to new reaction route will open a door to further develop useful transformations by rational catalyst design.

A new hybrid method combining search and direct based construction ideas to generate all 4 × 4 involutory maximum distance separable (MDS) matrices over binary field extensions.

This article presents a new hybrid method (combining search based methods and direct construction methods) to generate all involutory maximum distance separable (MDS) matrices over . The proposed method reduces the search space complexity at the level of , where n represents the number of all invertible matrices over to be searched for. Hence, this enables us to generate all involutory MDS matrices over and . After applying global optimization technique that supports higher Exclusive-OR (XOR) gates (e.g., XOR3, XOR4) to the generated matrices, to the best of our knowledge, we generate the lightest involutory/non-involutory MDS matrices known over , and in terms of XOR count. In this context, we present new involutory MDS matrices over , and , which can be implemented by 13 XOR operations with depth 5, 25 XOR operations with depth 5 and 42 XOR operations with depth 4, respectively. Finally, we denote a new property of Hadamard matrix, i.e., (involutory and MDS) Hadamard matrix form is, in fact, a representative matrix form that can be used to generate a small subset of all involutory MDS matrices, where k > 1. For k = 1, Hadamard matrix form can be used to generate all involutory MDS matrices.

Conservation law and Lie symmetry analysis of the Zakharov–Kuznetsov equation

The Zakharov–Kuznetsov (ZK) equation is extensively investigated in this study. This equation is a two-dimensional (2D) generalization of the well-known Korteweg–de Vries (KdV) equation, which is spatially limited as the 1D model of weakly nonlinear waves in shallow water. In this paper, we use three different methods to solve the conservation laws of it. First, the direct construction method is used to calculate the multipliers of the objective equation, and the conservation laws can be obtained by using the multipliers. Then its strict self-adjoint property is verified, and its conservation laws are solved by Ibragimov’s method. Finally, the conservation laws of the target equation are solved by Noether’s theorem. Then we calculate some exact solutions of the ZK equation by the extended Kudryashov method and seek a few solutions in terms of hyperbolic tangent functions and [Formula: see text]. Meanwhile, the conservation law analysis of the target equation is carried out, and its Lie point symmetries, reduced order form and invariant solution are determined. In the end, the Hamiltonian structure of the target equation, the generalized pre-symplectic that maps symmetries into adjoint-symmetries and some of its soliton solutions are calculated.

Spatial Path Smoothing for Car-like Robots Using Corridor-Based Quadratic Optimization

The global planning module of car-like robots usually plans a coarse spatial path, which may be non-smooth and kinematically infeasible for car-like robots. This study proposes an efficient spatial path smoothing approach, which is capable of optimizing a rough spatial path to be a high quality one. Two novel designs contribute to the proposed approach. One is a direct corridor construction method that provides an optimization region for path optimization. Based on a redefined path representation in the generated corridor, the second one is a core spatial path optimization method, where the optimization problem is formulated as a multi-objective quadratic programming (QP) with corridor and maximum-curvature constraints. Meanwhile, integrating a two-steps strategy into an optimization process yields a good trade-off between efficiency and quality. Experiment results validate that the proposed approach has the ability to online generate a high quality path.

Selective access to fused tetrahydroquinolines via a copper-catalysed oxidative three-component annulation reaction.

Via a copper-catalyzed three-component annulation reaction, we herein report a new method for the direct and syn-selective construction of cyclic ether-fused tetrahydroquinolines from readily available secondary anilines, saturated five or six-membered cyclic ethers, and paraformaldehyde. The synthesis features operational simplicity, excellent step and atom efficiency, good functionality and substrate compatibility. In comparison with the reported synthetic protocols capable of synthesizing N-alkyl fused tetrahydroquinolines, this newly developed chemistry allows access to both N-alkyl and N-aryl products. The current work complements the preparation of fused tetrahydroquinolines.

A Gaussian process-driven worst realistic imperfection method for cylindrical shells by limited data

In this study, we propose a Gaussian process-driven worst imperfection method to generate simulated geometric imperfections and find the lower limit of buckling capability. First, we utilize the nested stochastic Kriging to estimate the global trend and envelopes of the geometric imperfections. Second, the expansion optimal linear estimation and direct weighting construction method are used to expand limited data, which allow the simulated geometric imperfections to have the same characteristics as the initial data. Third, two magnitude-based constraints are provided, which can make the simulated geometric imperfections more consistent with the realistic data and can represent more design space. Finally, for the cylindrical shells, the data pre-processing method is further provided in this paper. Two numerical examples with assumed geometric imperfections are used to validate the proposed method, and the minimum buckling capacity of a cylindrical shell with 8 realistic geometric imperfections data is estimated. The results show that the proposed method can achieve the best performance in terms of accuracy, efficiency, and robustness.

Controllability Results for First Order Impulsive Fuzzy Differential Systems

In this paper, we investigate the controllability of first-order impulsive fuzzy differential equations. Using the direct construction method, the controllability of first-order linear impulsive fuzzy differential equations is considered with a<0, the (c1) solution, and a<0, the (c2) solution, respectively.In addition, by employing the Banach fixed-point theorem, the controllability of first-order nonlinear impulsive fuzzy differential equations is studied. Finally, examples are presented to illustrate our theoretical results.

Direct Construction of Quinoxaline Derivatives from Vicinal Diols and o‐Nitroanilines via NaOH‐Mediated Intermolecular Cascade Redox and Annulation Reactions

AbstractAn alkali base, such as NaOH, alone can effectively mediate the intermolecular cascade redox and annulation reactions of o‐nitroanilines with vicinal diols, providing an efficient transition metal‐free method for direct construction of the useful quinoxaline derivatives. This method tolerates a wide range of substrates, can be readily performed in open air and scaled up for gram synthesis of several pharmaceutically and biologically active quinoxaline derivatives. Studies revealed that the nitro group works as the internal oxidant and the diols the reductant. Possible reaction paths were also proposed based on control reactions. For simple operation of the reactions, requiring no external reducing and oxidizing reagents, no inert atmosphere protection and no transition metal catalysts/ligands but only a water‐soluble alkali base, and having no transition metal residue contaminant in the products, this method may be a relatively greener and practical way for construction of the quinoxaline skeleton, especially for the pharmacy‐ or biology‐oriented quinoxaline derivatives.

Controllability Results for First Order Linear Fuzzy Differential Systems

In this paper, we investigate the controllability of first order linear fuzzy differential systems. We use the direct construction method to derive the controllability results for three types of first order linear fuzzy controlled systems via (c1)-solution and (c2)-solution, respectively. An example is presented to illustrate our theoretical results.

Construction and Characterization of Optical Orthogonal Codes (n,w,1) for Fast Frequency Hopping-Optical Code Division Multiple Access

This paper investigates a new combinatorial construction approach based on cyclic difference packings for the construction of an optical orthogonal code that is suitable as a time spreading sequence for fast frequency hopping optical code division multiple access (OCDM) systems. The proposed construction provides a solution to the electrical decoding delay problem when compared to its optical counterpart, as well as other optimization issues. The criteria for optimizing the performance of such an OCDMA system are provided, namely: the flexibility and simplicity in constructing the optimal code for any length and weight, a reduction in the encoding/decoding complexity that complies with changes in the fast frequency hopping system, and the provision of system transfer transparency, a decoding rule that exploits the embedded asymmetric error correcting capability of the code. Our neighbor difference approach refers to the partition of different solutions into sub-classes, given in the correlation matrix form. It takes into account both direct and recursive combinatorial code construction methods, and the resulting characteristics are evaluated accordingly. A performance analysis based on the OCDMA channel is given, and a comparison with other difference family solutions is performed.

Optimization of the Manufacturing Process by Molding Cobalt-Chrome Alloys in Assembled Dental Frameworks

In oral rehabilitation, the treatment of partial edentulism (PEd) is performed by removable partial dentures (RPD) or assembled prosthetic works (APW) composed of several components, fixed to the prosthetic field (Pa) and a removable one (Pb), in order to facilitate the daily hygiene but also the damping of the occlusal forces applied in mastication. Cobalt-Chromium alloys are materials used to manufacture modern prosthetic assembles. In order for this study to be relevant, it was necessary to standardize the design of the framework (Pa) in terms of shape and volume so that the experiment could be reproducible for the five Co-Cr alloys: 0-A (Co-Cr-Mo), 5-A and 10-A (Co-Cr-Mo-W), 15-A and 16.4-A (Co-Cr-W-Fe) and for the three fabrication methods of dental assembled prosthetic frameworks: refractory duplicate method (RD) resulting removable framework (Pb), direct construction method (DC) resulting removable framework (Pb-) and casting over metal method (CoM) resulting removable framework (Pb+). The time allocated to the adaptation process (AP), mechanical processing and sandblasting, in order to assemble the two components was between 43–70 min, even though the assembly between the Pa-framework and the complementary framework (Pb+) was not necessary, CoM-method hs been provide the elimination of AP step. By applying the arithmetic simple rule of three, the percentages for each of the three methods used were calculated, the values of the difference were obtained. The CoM method improves the joining precision between the components of the removable assembly of prosthetic frameworks by 91.7% compared to the RD method and by 80.62% compared to the DC method. According to the efficiency of the methods used in the precision of joining between frameworks components, their order is: casting over metal, direct construction and refractory duplicate method.

Direct construction of three-level designs with less β-aberration

The β-wordlength pattern has been justified as an appropriate criterion for measuring designs with quantitative factors. However, construction methods of designs with less β-aberration have not been fully investigated. In this paper, some properties of β-wordlength pattern for three-level designs will be firstly provided, and then a direct construction method is proposed to generate three-level designs with using 2-level orthogonal arrays. Subsequently, two methods of level rearrangement are discussed to reduce the β 3 and β 4 of the resultant designs. Moreover, the advantages of these two methods are also compared. Finally, numerical examples are presented to illustrate the effectiveness of the proposed methods.

Forward rank‐dependent performance criteria: Time‐consistent investment under probability distortion

AbstractWe introduce the concept of forward rank‐dependent performance criteria, extending the original notion to forward criteria that incorporate probability distortions. A fundamental challenge is how to reconcile the time‐consistent nature of forward performance criteria with the time‐inconsistency stemming from probability distortions. For this, we first propose two distinct definitions, one based on the preservation of performance value and the other on the time‐consistency of policies and, in turn, establish their equivalence. We then fully characterize the viable class of probability distortion processes and provide the following dichotomy: it is either the case that the probability distortions are degenerate in the sense that the investor would never invest in the risky assets, or the marginal probability distortion equals to a normalized power of the quantile function of the pricing kernel. We also characterize the optimal wealth process, whose structure motivates the introduction of a new, ‘distorted’ measure and a related market. We then build a striking correspondence between the forward rank‐dependent criteria in the original market and forward criteria without probability distortions in the auxiliary market. This connection also provides a direct construction method for forward rank‐dependent criteria. Finally, our results on forward rank‐dependent performance criteria motivate us to revisit the classical (backward) setting. We follow the so‐called dynamic utility approach and derive conditions for existence and a construction of dynamic rank‐dependent utility processes.

A Survey of Computational Intelligence Techniques for Wind Power Uncertainty Quantification in Smart Grids.

The high penetration level of renewable energy is thought to be one of the basic characteristics of future smart grids. Wind power, as one of the most increasing renewable energy, has brought a large number of uncertainties into the power systems. These uncertainties would require system operators to change their traditional ways of decision-making. This article provides a comprehensive survey of computational intelligence techniques for wind power uncertainty quantification in smart grids. First, prediction intervals (PIs) are introduced as a means to quantify the uncertainties in wind power forecasts. Various PI evaluation indices, including the latest trends in comprehensive evaluation techniques, are compared. Furthermore, computational intelligence-based PI construction methods are summarized and classified into traditional methods (parametric) and direct PI construction methods (nonparametric). In the second part of this article, methods of incorporating wind power forecast uncertainties into power system decision-making processes are investigated. Three techniques, namely, stochastic models, fuzzy logic models, and robust optimization, and different power system applications using these techniques are reviewed. Finally, future research directions, such as spatiotemporal and hierarchical forecasting, deep learning-based methods, and integration of predictive uncertainty estimates into the decision-making process, are discussed. This survey can benefit the readers by providing a complete technical summary of wind power uncertainty quantification and decision-making in smart grids.

An asymmetric information mean‐field type linear‐quadratic stochastic Stackelberg differential game with one leader and two followers

SummaryThis paper is concerned with an asymmetric information linear‐quadratic (AILQ) stochastic Stackelberg differential game with one leader and two followers, where the game system is governed by mean‐field type stochastic differential equation (MF‐SDE). With the help of two systems of Riccati equations, the followers solve a MF‐type stochastic LQ game problem with partial information first, and then, the leader turns to address an optimal control problem driven by linear MF‐type forward‐backward stochastic differential filtering equation (MF‐FBSDFE). By maximum principle, direct construction method and optimal filtering, the open‐loop Stackelberg solution is expressed as a feedback form of state, state estimation, and state mean.

Direct construction of globally D‐optimal designs for factors at two levels and main effects models

AbstractIn developing screening experiments for two‐level factors, practitioners typically are familiar with regular fractional factorial designs, which are orthogonal, globally D‐optimal (ie, 100% D‐efficient), and exist if is a power of two. In addition, nonregular D‐optimal orthogonal designs can be generated for almost any a multiple of four, the most notable being the family of Plackett and Burman1 designs. If resource constraints dictate that is not a multiple of four, while an orthogonal design for two‐level factors does not exist, one can still consider a D‐optimal design. Exchange algorithms are available in commercial computer software for creating highly D‐efficient designs. However, as the number of factors increases, computer searches eventually fail to find the globally optimal design for any or require impractical search times. In this article, we compile state‐of‐the‐art direct construction methods from the literature for producing globally D‐optimal designs for virtually any number of two‐level factors as well as any greater than the number of factors. We summarize the known methods as well as areas for continued research, with the intention of catalyzing research in extending these construction methods.

Conservation laws for partial differential equations based on the polynomial characteristic method

In this paper, the direct construction method combined with the differential polynomial characteristic set algorithm is used to complete conservation laws of PDE. The process of the direct construction method is to solve a system of linear determining equations, which is not easy to be solved. This paper uses the differential polynomial characteristic set algorithm to overcome the shortcoming, and constructs an explicit conservation law.