Comprehensive Calculations Research Articles

Electron Properties of Baicalein and its Derivatives via Quantum Chemistry Calculation: The Effect of Hydroxyl-substitution at A and C Rings

Abstract: The electron properties of baicalein-family are of great importance in influencing its properties and corresponding bioactivities. In this work, we conducted comprehensive quantum chemistry calculations on pristine baicalein, and its two hydroxyl-substituted derivatives where the hydroxylsubstitution respectively occur at A and C rings. By contrasting with each other, the effects of the hydroxyl-substitution on the electron properties were studied from the aspects of the density of states, molecular orbital, electronic excitation, electrostatic potential, and electron delocalization. According to our computation, the hydroxyl-substitution results in variations in geometry and the consequent electron properties among the discussed molecules. Certainly, this research can contribute to the development of the research on the electron involved properties and the structure-property-activity relationship for the baicalein-family.

Exploring the efficacy of Re-Ni embedded KIT-6/H-Mor catalysts for renewable energy – A comprehensive experimental and theoretical (DFT) exploration

The global market for n-propyl benzene value is projected to reach $30.47 billion by 2030, with a CAGR of 4.3% from 2023 to 2030. This market analysis identifies diverse applications for propyl benzene, spanning the petroleum industry, industrial chemicals, automotive sector, and more. The research introduces eugenol, a compound derived from lignin, as a model compound for bio-oil to n-propyl benzene (bio-fuel analogs) production. A novel Re-Ni/KIT-6-H-Mordenite catalyst is developed for efficient hydrodeoxygenation of eugenol, showcasing high conversion rates and selectivity under moderate temperatures. Comprehensive characterization techniques and theoretical calculations highlight the synergistic interaction between Re and Ni metals. The catalyst’s reusability and successful application for bio-fuel production under atmospheric conditions further validate its potential. This study pioneers the exploration of Re-Ni bimetallic catalysts for HDO of lignin-derived compounds, offering valuable insights into sustainable bio-fuel development.

Robust global optimization of plasmonic filter based on Q factor analysis using graded index

Abstract To reduce the impact of uncertainties in various manufacturing processes while maintaining satisfactory performance level, we propose a robust global optimization approach for plasmonic filters based on extraordinary optical transmission by use of Q factor analysis with reasonable computational cost. The gradient index is employed as a metric for robustness, and the multiobjective genetic algorithm is selected as a global optimization tool. The figures of merit and gradient index are chosen as two objective functions with the design variables being the slit width, slit height, and period of the slit array, respectively. The finite element method is employed to investigate a variety of optical properties rigorously. The numerical optimization results demonstrate that the proposed approach provides improved effectiveness and efficiency in designing plasmonic filters under fabrication uncertainties by using Q factor analysis. The method proposed in this study enables systematic robust optimization while accounting for manufacturing uncertainties, which would be infeasible under typical time constraints. Specifically, within the proposed optimization framework, Q factor analysis can be employed due to a 20.60-times reduction in computational time. To the best of our knowledge, this represents the first robust optimization design for enhanced filter performance based on Q factor analysis in EOT, necessitating comprehensive spectrum calculations alongside fabrication tolerance considerations.

Self-Healable Hydrogels from Vegetable Oil: Preparation, Mechanism, and Applications.

Hydrogels are indispensable for a variety of applications. Conventional biomaterial-based hydrogels, typically made from proteins or polysaccharides, often suffer from high costs, poor mechanical properties, and limited chemical functionality for modification. In this work, we present a novel hydrogel developed from modified castor oil, which is a renewable and cost-effective resource. Castor oil-based oligomer (CG) was synthesized using glycidyl methacrylate and triethylamine via ring-opening polymerization. The oligomer formed a gel only with Cu2+ ions among the various systematically studied metal ions. Comprehensive density functional theory calculations, atoms in molecules analysis, and steady and dynamic shear rheology were conducted to investigate the metal-binding sites and metal-oligomer interactions as well as the self-healing and viscoelastic properties of the oil-based hydrogels. The hydrogel exhibited 94% self-healing efficiency and performed as a recyclable rhodamine B dye adsorbent (73-90%). This innovative approach offers a novel, cost-effective, and sustainable alternative to traditional hydrogels, paving the way for advanced applications.

Including Lifetime Hydraulic Turbine Cost into Short-Term Hybrid Scheduling of Hydro and Solar

In traditional short-term hydropower scheduling problems, which usually determine the optimal power generation schedules within one week, the off-design zone of a hydraulic turbine is modeled as a forbidden zone due to the significantly increased risk of turbine damage when operating within this zone. However, it is still plausible to occasionally operate within this zone for short durations under real-world circumstances. With the integration of Variable Renewable Energy (VRE) into the power system, hydropower, as a dispatchable energy resource, operates complementarily with VRE to smooth overall power generation and enhance system performance. The rapid and frequent adjustments in output power make it inevitable for the hydraulic turbine to operate in the off-design zone. This paper introduces the operating zones associated with various production costs derived from fatigue analysis of the hydraulic turbine and calculated based on the turbine replacement cost. These costs are incorporated into a short-term hybrid scheduling tool based on Mixed Integer Linear Programming (MILP). Including production costs in the optimization problem shifts the turbine’s working point from a high-cost zone to a low-cost zone. The resulting production schedule for a Hydro-Solar hybrid power system considers not only short-term economic factors such as day-ahead market prices and water value but also lifetime hydraulic turbine cost, leading to a more comprehensive calculation of the production plan. This research provides valuable insights into the sustainable operation of hydropower plants, balancing short-term profits with lifetime hydraulic turbine costs.

Probabilistic modeling of multivariate extreme non-Gaussian wind loads and its applications in envelope engineering

Probabilistic modeling for non-Gaussian wind load fields under extreme winds is crucial to the quantitative risk and reliability analysis of envelope structures. Based on the multi-point synchronous wind load data during typhoons, a probabilistic model is proposed to characterize multivariate non-Gaussian wind loads to improve the accuracy of the risk analysis considering data dimension reduction. In the proposed model, the Pareto distribution function is utilized to fit the marginal distribution, and the copula function is employed to construct the dependent structure of wind loads from different locations. In the marginal fitted results, the extreme wind load value in the edge region is about 0.10–0.15 higher than those from inner measurement points at quantile p = 95 %. In addition, the variation gradient from the different variable directions is approximately equal, and a sharp variation occurs at the point (0.10, 0.10) for bivariate joint distributions. Engineering applications given in this article are composed of three parts: calculating regional exceeding probability, estimating wind load vector under a specific regional exceeding probability, and determining the location of joint extreme wind loads using the joint gradient value. Finally, risk analysis of existing roof coverings is carried out, the edge corner region is weaker, and two engineering recommendations are given. For determining the regional design wind load, a comprehensive calculation framework considering the temporal dependence of different locations is established, and the reduction rates are in the range (5 %, 25 %).

A new calculation method for the response of active-passive bridge piles considering pile-soil interface friction

The pile foundation of bridges under unregulated surcharge loads experiences a complex force pattern, which is subject to active loads and passive loads. In this paper, a more comprehensive calculation method for the response of active-passive piles was proposed, which considered the effect of pile-soil interface friction and soil stress states on the passive loads. First, the Ito theory was improved by adopting the adhesion c a and external friction angle φ a to characterize the pile-soil interface friction. Then, the soil around the pile in elastic, elastoplastic, and plastic flow states was considered to calculate the variation of the passive load. Finally, a nonlinear p-y curve was introduced to establish the calculation model of active-passive piles, and the finite difference program CPAPP was prepared for the solution. The results show that the pile response calculated by CPAPP is consistent with the field measurement, indicating that the proposed calculation method has high accuracy. When the soil is in an elastic state, the pile-soil interface friction does not affect the passive load. When the soil is in a plastic state, the passive load is closely related to soil strength parameters and pile-soil interface friction parameters.

D-Electrons of Platinum Alloy Steering CO Pathway for Low-charge Potential Li-CO2 Batteries.

Aprotic Li-CO2 batteries suffer from sluggish solid-solid co-oxidation kinetics of C and Li2CO3, requiring extremely high charging potentials and leading to serious side reactions and poor energy efficiency. Herein, we introduce a novel approach to address these challenges by modulating the reaction pathway with tailored Pt d-electrons and develop an aprotic Li-CO2 battery with CO and Li2CO3 as the main discharge products. Note that the gas-solid co-oxidation reaction between CO and Li2CO3 is both kinetically and thermodynamically more favorable. Consequently, the Li-CO2 batteries with CoPt alloy-supported on nitrogen-doped carbon nanofiber (CoPt@NCNF) cathode exhibit a charging potential of 2.89 V at 50 µA cm-2, which is the lowest charging potential to date. Moreover, the CoPt@NCNF cathode also shows exceptional cycling stability (218 cycles at 50 µA cm-2) and high energy efficiency up to 74.6%. Comprehensive experiments and theoretical calculations reveal that the lowered d-band center of CoPt alloy effectively promotes CO desorption and inhibits further CO reduction to C. This work provides promising insights into developing efficient and CO-selective Li-CO2 batteries.

D‐Electrons of Platinum Alloy Steering CO Pathway for Low‐charge Potential Li‐CO2 Batteries

Aprotic Li‐CO2 batteries suffer from sluggish solid‐solid co‐oxidation kinetics of C and Li2CO3, requiring extremely high charging potentials and leading to serious side reactions and poor energy efficiency. Herein, we introduce a novel approach to address these challenges by modulating the reaction pathway with tailored Pt d‐electrons and develop an aprotic Li‐CO2 battery with CO and Li2CO3 as the main discharge products. Note that the gas‐solid co‐oxidation reaction between CO and Li2CO3 is both kinetically and thermodynamically more favorable. Consequently, the Li‐CO2 batteries with CoPt alloy‐supported on nitrogen‐doped carbon nanofiber (CoPt@NCNF) cathode exhibit a charging potential of 2.89 V at 50 µA cm‐2, which is the lowest charging potential to date. Moreover, the CoPt@NCNF cathode also shows exceptional cycling stability (218 cycles at 50 µA cm‐2) and high energy efficiency up to 74.6%. Comprehensive experiments and theoretical calculations reveal that the lowered d‐band center of CoPt alloy effectively promotes CO desorption and inhibits further CO reduction to C. This work provides promising insights into developing efficient and CO‐selective Li‐CO2 batteries.

Rupture energy coupling of alkali washing tower cylinder

The energy generated by the container during the explosion induces destructive effects on the surrounding objects and itself, such as deformation, compression, rupture, etc. The explosive energy is one of the richest pieces of evidence in the analysis of the accident cause, and therefore a comprehensive analysis of the accident explosive energy is essential for determining accident properties. Considering the rupture accident of an alkali washing tower in an aromatic hydrocarbon plant as an example, the destructive energy and the rupture internal pressure are estimated to ascertain the explosive properties of the accident by analyzing the field damage characteristics. This study aims to conduct a comprehensive analysis and calculation of the energy associated with an alkali washing tower rupture accident. The objective is to determine the cause of the accident, which can be attributed to the combined effect of wall thickness reduction and fluctuations of production process parameters. The findings of this analysis will serve as a scientific basis for the examination of similar accidents and the formulation of safety protection measures.

Identification of optically active vibrational modes of columbite AB2O6 using the correlation method

In the modern era, the examination of molecular structure heavily relies on the application of infrared and Raman spectra within crystalline structures. These methodologies are essential in understanding the arrangement of atoms within molecules and the internal forces governing them. An essential aspect of this analysis involves identifying vibrational modes that can be detected optically. The correlation method is employed to establish rules for selecting these vibrational modes, both in crystals and molecules, through a systematic calculation process that aids in predicting their activity in Infrared (IR) and Raman spectra. The correlation method utilizes group theory to determine which vibrational modes are spectroscopically active in crystals. In our research, our aim is to employ this method to identify the irreducible representations and determine the IR and Raman active vibrational modes of orthorhombic AB2O6 compounds within the Pbcn space group. By conducting comprehensive group theory calculations, our objective is to elucidate the spectroscopic properties using the correlation method.

Development and Validation of a 30-Day Point-Scoring Risk Calculator for Open Groin Vascular Surgery: The George Washington Groin Score

BackgroundOpen groin vascular surgeries are important in managing peripheral arterial diseases. Given its inherent risks and the diverse patient profiles, there is a need for risk assessment tools. This study aimed to develop a 30-d point-scoring risk calculator for patients undergoing open groin vascular surgeries. MethodsPatients underwent open groin vascular surgery, including aortobifemoral, axillofemoral, femorofemoral, iliofemoral, femoral-popliteal, and femoral-tibial bypass as well as thromboendarterectomy, were identified in American College of Surgeons National Surgical Quality Improvement Program database from 2005 to 2021. Patients were randomly sampled into experimental (2/3) and validation (1/3) groups. The George Washington (GW) groin score, a weighted point-scoring system, was developed for 30-d mortality from multivariable regression on preoperative risk variables by Sullivan's method. GW groin score was subjected to internal and external validation. Furthermore, the effectiveness of GW groin score was evaluated in 30-d major surgical complications. ResultsA total of 129,424 patients were analyzed, with 86,715 allocated to experimental group and 42,709 to validation group. GW groin score is derived as follows: aortobifemoral bypass (2 points), axillofemoral bypass (1 point), age (>75 y, 2 points; 65-75 y, 1 point), disseminated cancer (2 points), emergent presentation (1 point), American Society of Anesthesiology score 4 or 5 (1 point), dialysis (1 point), and preoperative sepsis (1 point).GW groin score exhibited robust discrimination (c-statistic = 0.794, 95% CI = 0.786-0.803) and calibration (Brier score = 0.029). The transition from individual preoperative variables (c-statistic = 0.809, 95% CI = 0.801-0.818) to the point-scoring system was successful and external validation of the score was confirmed (c-statistic = 0.789, 95% CI = 0.777-0.801, Brier score = 0.030). Furthermore, GW groin score can effectively discriminate major surgical complications. ConclusionsThis study developed GW groin score, a concise and comprehensive 10-point risk calculator. This well-validated score demonstrates robust discriminative and predictive abilities for 30-d mortality and major surgical complications following open groin vascular surgeries. GW groin score can anticipate potential perioperative complications and guide treatment decisions.

Computational Justification Towards Detection of Dual Anions on a Single Molecular Platform: The Role of Solvent in Decoration of Dual Channels

ABSTRACTRatiometric optical detection of analytes is a convenient strategy as the technique is devoid of relative error and background correction. Herein, solvent‐guided ratiometric optical recognition of fluoride and bisulfate anions by a low‐cost, “off‐the‐shelf” bioactive molecule, harmane (HRH) is thoroughly explored. Interestingly, solvent plays a dynamic role in the selective recognition of the dual anions via the dual channels of HRH in an intelligent manner. The probe displays high‐fidelity recognition behavior towards fluoride ion in an aprotic solvent (acetonitrile) and towards bisulfate ion in a protic environment (acetonitrile/water; 5:1; v/v). Both the channels of HRH are very selective for a particular anion (F−/HSO4−) in a specific solvent. Organized and comprehensive theoretical calculation denotes that hydrogen bonding between the acidic pyrrolic proton of HRH and fluoride for the first channel and the acidic proton of bisulfate and the pyridinic nitrogen for the second channel of HRH led to the formation of a hydrogen‐bonded ion pair (HBIP). Consequently, significant optical changes are observed in the visible region, which is convenient for real‐life detection of F− and HSO4− independently. The essential role of solvent in tuning the dual channels of HRH is an important artifact in the literature of fundamental photochemistry.

Hierarchical pore-enhanced ion transport and defect-induced dual strong interactions for highly efficient lithium extraction

In the past decade, adsorption method has attracted great attention on the lithium extraction. The key issue in adsorption technology is to develop adsorbents with high adsorption capacity, selectivity, and recycle-stability. Here, the highly efficient metal–organic framework adsorbents were developed for lithium extraction, which were fabricated by the in-situ conversion of MIL-121 in alkali solution. The adsorbent after acid activation, termed as H-CAOMIL, was featured with the hierarchical porosity, enhanced density of free carboxylic groups, and exposed aluminum-oxygen defect sites to enhance the ion transport and provide dual strong interaction for Li+. H-CAOMIL exhibited the remarkable Li+ adsorption capacity (QLi+ = 5.28 mg/g) and selectivity (αKLi = 21.33, αNaLi= 9) from low-concentration lithium-containing solutions. Moreover, the H-CAOMIL can be easily regenerated in weakly acidic solution. Impressively, Li+ adsorption capacity retained at 92 % of the initial capacity even after five adsorption–desorption cycles. Furthermore, the comprehensive characterizations and theoretical calculations indicated that the specific coordination of COO-Li and AlO-Li played a crucial role in the recovery capacity and selectivity of Li+. This work offers precious insights for the future exploration of highly efficient adsorbents for lithium extraction.

Aggregated health risk assessment of perfluoroalkyl acids migrated from convenience food contact materials.

Ingestion of perfluoroalkyl acids (PFAAs) via contaminated food contact materials (FCMs) is an important human exposure source. This study adopts a toxicity equivalent approach to evaluate the collective health risk of multiple PFAAs in FCMs. A comprehensive extraction and analysis of 21 PFAAs in FCMs was performed. Among the analyzed substances, 15 PFAAs were detected. Migration experiment using three food simulants revealed the migration range of seven PFAAs from FCMs into the simulant to be 0.47-46.7ng/cm2. The hazard quotient results suggest minimal health risk, except for 9% of packaged samples where perfluorooctanoic acid (PFOA) poses a higher risk. Utilizing PFOA toxic equivalent concentrations, comprehensive risk calculations showed ∼77% of samples potentially posing elevated health risks due to PFAA exposure. This emphasizes the substantial contribution of PFAAs beyond PFOA and underscores the importance of considering them in related assessments. The aggregated risk assessment reflects actual exposure circumstances more accurately.

A design of green slurry for copper/cobalt barrier-step chemical mechanical polishing with controlled removal selectivity and dynamic galvanic corrosion inhibition

Chemical mechanical polishing (CMP) is one critical process in chip fabrication while also regarded as highly polluting due to the toxic CMP slurries. Though green slurries were recently proposed and developed, few of them could satisfy the stringent requirements of the simultaneous planarization of copper/cobalt heterogeneous structure, especially in technology node below 14 nm. In this contribution, a green CMP slurry with a biodegradable chelator methylglycinediacetic acid (MGDA) and a plant-extract inhibitor disproportionated rosin (DR) was designed. Nanometer-scale smooth surface, removal selectivity, galvanic corrosion inhibition and residual control was realized with the developed slurry. Through comprehensive experiments and theoretical calculations, the roles of the ingredients played and their synergistic material removal mechanism were elucidated. MGDA partially dissolved the oxide film, especially Cu(OH)2 formed by H2O2 and the porous film could be more easily removed by the mechanical friction of abrasive particles. DR ensured post-polished surface quality by inhibiting over-corrosion through adsorption on copper surface. Density-functional-theory calculations analyzed DR's molecular reactivity and determined the most stable parallel adsorption configuration. The work provides useful insights into the fundamental interactions of components in CMP process. In addition, both MGDA and DR are commercially available with low cost, showing great practical application prospect in low-technology-node chip fabrication.

Six new prenylated flavonoids from Dodonaea viscosa with anti-Zika virus activity

Six new prenylated flavonoids, named visconaeas A-F (1–6), and eleven known isopentenyl flavonoids (7–17) were isolated from Dodonaea viscosa (L.) Jacq. The structures of the separated compounds were determined through comprehensive spectral analysis and quantum chemical calculations. These compounds were tested for their anti-Zika virus and cytotoxicity activities. The results indicated that compound 4 showed low cytotoxicity and strong anti-Zika virus potential with EC50 16.34 μM.

Dual electric field and defect engineering induced multi-channel electron transfer for boosting photocatalytic hydrogen production on Cu2+-doped ZnMoO4/ZnIn2S4 heterojunction

Serious recombination of photogenerated carriers is the bottleneck problem of achieving high-performance photocatalytic reaction. A high efficient Cu2+-doped ZnMoO4/ZnIn2S4 (CZMOZIS) heterojunction was synthesized by hydrothermal method. The CZMOZIS heterostructure achieved hydrogen production of 11637.5 µmol g−1 within 5 h, which was 9.7 times higher than that of pure ZnIn2S4. Comprehensive characterization and theoretical calculation demonstrated that the CZMOZIS composites exhibited broad light absorption, an increased specific surface area and an optimized Gibbs free energy. The presence of oxygen vacancies in CZMOZIS composites was confirmed by X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy, revealing the formation of defect levels below the conduction band (CB) of ZnMoO4. Kelvin probe force microscopy (KPFM) and Zeta potential demonstrated that the intrinsic electric field (IEF) of the CZMOZIS heterojunction was enhanced, which may be attributed to the generation of polarization electric field (PEF). The double electric field provided a robust driving force for the photogenerated carrier migration and separation. The electrons in the CB and defect levels of Cu2+-ZnMoO4 could be coupled with the holes of ZnIn2S4, thereby forming a multi-channel electron transfer. This work provides a theoretical support for promoting charge transfer to improve photocatalytic performance by dual electric field and defect engineering.

Immunosuppressive leucosceptrane-type sesterterpenoids with antipodal cyclopentenones isolated from Leucosceptrum canum

Ten undescribed leucosceptrane-type sesterterpenoids with antipodal cyclopentenone moieties were isolated from the leaves of Leucosceptrum canum. Their structures including absolute configurations were elucidated by comprehensive spectroscopic analyses (including 1D and 2D NMR, and HRMS) and ECD calculations. In vitro immunosuppressive effects of these sesterterpenoids against the proliferation of T cells and the secretion of cytokine IFN-γ were evaluated. Among them, 11α-H-leucosceptroid C, 5,13-dehydro-11α-H-leucosceptroid C, 5,13-dehydro- 11β-hydroxy-leucosceptroid C, and 5,13-dehydro-11α-hydroxy-leucosceptroid C significantly inhibited IFN-γ secretion with IC50 values of 12.55-23.62 μM. More remarkable inhibitory effects against IFN-γ secretion were observed for 5,13-dehydro-11β-hydroxy-leucosceptroid D, leucosceptroid U, 14-epi-leucosceptroid U, leucosceptroid V, and 14-epi-leucosceptroid V, with IC50 values of 4.32-9.47 μM.

Encapsulation of linear carbon chains in single-walled carbon nanotubes: Towards 1D van der Waals heterostructures for high-efficiency excitonic solar cells

One-dimensional van der Waals heterostructures (1D vdW HTs) based on single-walled carbon nanotubes (SWCNTs) encapsulating linear carbon chains (LCCs) with tunable optoelectronic properties provide a fresh ground for efficient excitonic solar cells (XSCs) alternative to those based on 2D monolayer materials. As an effort to identify for the first time 1D vdW HTs for efficient XSCs application, we perform here a systematic theoretical investigation on the energetic and structural stability, optoelectronic and photovoltaic properties of 1D vdW HTs based on SWCNTs encapsulating 50 symmetrical LCCs of different lengths, and capped with different conjugated endgroups through comprehensive first-principles calculations. We showed the fundamental role of the length and the endgroups effects in modulating the optoelectronic properties of LCCs. Through exploration of the energetic stability of the 1D vdW HTs of LCCs@SWCNTs from the universal force field (UFF) including vdW interactions, we determined the optimal SWCNTs diameters for which the resulting 1D vdW HTs are stable. Then, the band alignment in the 50 stable 1D vdW HTs of LCCs@SWCNTs is examined. Intriguingly, stable LCCs@SWCNTs are identified as type-II 1D vdW HTs complying the prerequisite of XSCs with strong optical absorption in the UV–visible-NIR spectral regions, and power conversion efficiency (PCE) reaching well over 21 %. These findings unravel the enormous potential of the 1D vdW HTs in designing next-generation XSCs devices competitive with state-of-the-art solar cells.