This paper addresses the transmission expansion planning problem under long- and short-term uncertainty. Long-term uncertainty pertains to changes across years (demand growth and future increase in ...production capacity), whereas short-term uncertainty pertains to changes within a year (demand and wind/solar power production variability, and equipment availability). This expansion problem is formulated as an adaptive robust optimization problem that provides protection against long-term uncertainty while carefully representing short-term uncertainty via scenarios. The problem is solved via a tailored implementation of the primal Benders' decomposition algorithm that focuses on an efficient solution of the subproblem. The effectiveness of the proposed algorithm to identify robust expansion plans and its computational efficiency are illustrated through a realistic case study.
Decomposing chemical interactions into bonds and other higher order interactions is a common practice to analyse chemical structures, and gave birth to many chemical concepts, despite the fact that ...the decomposition itself might be subjective in nature. Fragment molecular orbitals (FMOs) offer a more rigorous alternative to such intuition, but might be less interpretable due to extensive delocalisation in FMOs. Inspired by the Principal Component Analysis in statistics, we hereby present a novel framework, Principal Interacting Orbital (PIO) analysis, that can very quickly identify the “dominant interacting orbitals” that are semi‐localised and easily interpretable, while still maintaining mathematical rigor. Many chemical concepts that are often taken for granted, but could not be easily inferred from other computational techniques like FMO analysis, can now be visualised as PIOs. We have also illustrated, through various examples covering both organic and inorganic chemistry, how PIO analysis could help us pinpoint subtle features that might play determining roles in bonding and reactions.
Principal Interacting Orbitals: A novel framework has been developed, based on Principal Component Analysis (PCA), to identify the Principal Interacting Orbitals (PIOs) accounting for the bonding interaction between two chemical fragments. The novel framework has been employed to analyse structure, bonding, and reactivity for a number of examples covering various aspects of chemistry.
Modular bonding picture is a central part of chemical understanding as exemplified by the wide usage of Lewis structure as a chemical language to describe molecular electronic structures. A ...chemically intuitive bonding picture requires the descriptors to be localized and transferable. Molecular orbitals directly derived from quantum calculations are too delocalized to interpret in this regard, hence many efforts have been devoted to the development of bonding analysis methods. After a brief overview of various bonding analysis methods, this review outlines the framework of principal interacting orbital (PIO) analysis and presents its role in recovering intuitive chemical concepts and producing modular bonding pictures. The PIO analysis identifies the most important fragment orbitals that are involved in fragment interactions and characterizes a one‐to‐one orbital interaction pattern that underlies a unique set of bonding and anti‐bonding orbitals derived from pairwise orbital interactions between two fragments. By making use of the principal component analysis (PCA), PIO analysis can effectively combine complex delocalized interaction patterns involved in numerous molecular orbitals into a handful of localized PIOs to provide easily interpretable results with intimate connection to localized chemical concepts, while maintaining necessary delocalized features when dealing with systems that involve mutlicentered interactions such as cluster compounds and various reactions. Such adaptability guarantees the robustness of PIO analysis with respect to change of substituents and the transferability of obtained PIOs across different systems.
This article is categorized under:
Structure and Mechanism > Molecular Structures
The recently developed Principal Interacting Orbital analysis provides a bridge between chemical intuition and theoretical rigor for interfragment orbital interactions.
Facile fabrication of advanced electrode material is highly desired for novel electrochemical sensor development. Herein, cerium oxide (CeO2) nanoparticles were successfully loaded on reduced ...graphene oxide (RGO) by one-step hydrothermal synthesis approach, and the as-prepared nanocomposite (CeO2/RGO) was used as novel electrode material for electrochemical detection of tryptophan. The structure and composition of CeO2/RGO nanocomposite were fully characterized by transmission electron microscope (TEM), X-ray powder diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The electrochemical properties were characterized by several techniques such as cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). It was found that the CeO2/RGO nanocomposite electrode exhibits an enhanced peak current response compared with individual CeO2 or RGO material. The electrochemical sensor based CeO2/RGO material showed a selective and sensitive response toward tryptophan determination, and a linear range of 0.2–25 μM with a detection limit of 80 nM (S/N = 3) was achieved. The present electrochemical sensor displayed an excellent stability and reproducibility, and was successfully applied in the determination of tryptophan in real food and biological samples.
CeO2 was loaded on reduced graphene oxide (CeO2-RGO) and used as active electrode material for electrochemical detection of tryptophan in food and biological samples. Display omitted
•CeO2 loaded on reduced graphene oxide (CeO2-RGO) composite was facilely fabricated by a hydrothermal reduction approach.•The CeO2-RGO was used as a novel electrode material for tryptophan detection.•The present electrochemical sensor exhibited improved analytical performance.•The CeO2-RGO electrode material has been successfully used for tryptophan detection in milk and bovine serum samples.
Heterobiaryls are important pharmacophores that are challenging to prepare by traditional cross‐coupling methods. An alternative approach is presented where pyridines and diazines are converted into ...heteroaryl phosphonium salts and coupled with aryl boronic acids. Nickel catalysts are unique for selective heteroaryl transfer, and the reaction has a broad substrate scope that includes complex pharmaceuticals. Phosphonium ions also display orthogonal reactivity in cross‐couplings compared to halides, enabling chemoselective palladium‐ and nickel‐catalyzed coupling sequences.
Pyridines and diazines can be selectively converted into heterocyclic phosphonium salts that function as generic alternatives to heteroaryl halides in a nickel‐catalyzed Suzuki–Miyaura coupling reaction. Complex pyridines, drug‐like fragments, and pharmaceuticals can be arylated according to this two‐step method.
We investigate the impacts of the gravitational-wave (GW) standard siren observation of the Einstein Telescope (ET) on constraining the total neutrino mass. We simulate 1000 GW events that would be ...observed by the ET in its 10-year observation by taking the standard ΛCDM cosmology as a fiducial model. We combine the simulated GW data with other cosmological observations including cosmic microwave background (CMB), baryon acoustic oscillations (BAO), and type Ia supernovae (SN). We consider three mass hierarchy cases for the neutrino mass, i.e., normal hierarchy (NH), inverted hierarchy (IH), and degenerate hierarchy (DH). Using Planck+BAO+SN, we obtain ∑mν<0.175 eV for the NH case, ∑mν<0.200 eV for the IH case, and ∑mν<0.136 eV for the DH case. After considering the GW data, i.e., using Planck+BAO+SN+GW, the constraint results become ∑mν<0.151 eV for the NH case, ∑mν<0.185 eV for the IH case, and ∑mν<0.122 eV for the DH case. We find that the GW data can help reduce the upper limits of ∑mν by 13.7%, 7.5%, and 10.3% for the NH, IH, and DH cases, respectively. In addition, we find that the GW data can also help break the degeneracies between ∑mν and other parameters. We show that the GW data of the ET could greatly improve the constraint accuracies of cosmological parameters.
A
bstract
We systematically calculate the quantum extremal surface (QES) associated with Hawking radiation for general
D
-dimensional (
D ≥
2) asymptotically flat (or AdS) eternal black holes using ...the island formula. We collect the Hawking radiation particles by a non-gravitational bath and find that a QES exists in the near-horizon region outside the black hole when
c
·
G
(
D
)
is smaller enough where
c
is the central charge of the conformal matter and
G
(
D
)
the
D
-dimensional Newton constant. The locations of the QES in these backgrounds are obtained and the late-time radiation entropy saturates the two times of black hole entropy. Finally, we numerically check that the no island configuration exists once
c
·
G
(
D
)
exceeds a certain upper bound in two-dimensional generalized dilaton theories (GDT). When
c
·
G
(
D
)
close to the upper bound, the backreaction of the matter field on the background can not be neglected. We also consider the conditions of existence of the island configuration with the backreaction and prove that the upper bound also exist for the Witten black hole and Weyl-related Witten black hole.
MicroRNAs (miRNA) play critical roles in regulating gene expressions at the posttranscriptional levels. The prediction of disease-related miRNA is vital to the further investigation of miRNA's ...involvement in the pathogenesis of disease. In previous years, biological experimentation is the main method used to identify whether miRNA was associated with a given disease. With increasing biological information and the appearance of new miRNAs every year, experimental identification of disease-related miRNAs poses considerable difficulties (e.g. time-consumption and high cost). Because of the limitations of experimental methods in determining the relationship between miRNAs and diseases, computational methods have been proposed. A key to predict potential disease-related miRNA based on networks is the calculation of similarity among diseases and miRNA over the networks. Different strategies lead to different results. In this review, we summarize the existing computational approaches and present the confronted difficulties that help understand the research status. We also discuss the principles, efficiency and differences among these methods. The comprehensive comparison and discussion elucidated in this work provide constructive insights into the matter.
Inversion symmetry breaking is critical for many quantum effects and fundamental for spin‐orbit torque, which is crucial for next‐generation spintronics. Recently, a novel type of gigantic intrinsic ...spin‐orbit torque is established in the topological van der Waals (vdW) magnet iron germanium telluride. However, it remains a puzzle because no clear evidence exists for interlayer inversion symmetry breaking. Here, the definitive evidence of broken inversion symmetry in iron germanium telluride directly measured by the second harmonic generation (SHG) technique is reported. The data show that the crystal symmetry reduces from centrosymmetric P63/mmc to noncentrosymmetric polar P3m1 space group, giving the threefold SHG pattern with dominant out‐of‐plane polarization. Additionally, the SHG response evolves from an isotropic pattern to a sharp threefold symmetry upon increasing Fe deficiency, mainly due to the transition from random defects to ordered Fe vacancies. Such SHG response is robust against temperature, ensuring unaltered crystalline symmetries above and below the ferromagnetic transition temperature. These findings add crucial new information to the understanding of this interesting vdW metal, iron germanium telluride: band topology, intrinsic spin‐orbit torque, and topological vdW polar metal states.
Definitive evidence for inversion symmetry breaking in iron germanium telluride (FGT) is reported using second harmonic generation (SHG). Fe deficiency and temperature dependent SHG evolution conclude that Fe vacancies break the inversion symmetry and reduce the centrosymmetric P63/mmc to noncentrosymmetric polar P3m1. These findings add crucial new information to understanding FGT: band topology, intrinsic spin orbit torque, skyrmion, and topological polar metal states.
Endowing a cholesteric liquid crystal elastomer (CLCE) exhibiting a helicoidal nanostructure with dynamically tailorable functionalities is of paramount significance for its emerging applications in ...diverse fields such as adaptive optics and soft robotics. Here, a mechanochromic, shape‐programmable and self‐healable CLCE is judiciously designed and synthesized through integrating dynamic covalent boronic ester bonds into the main‐chain CLCE polymer network. The circularly polarized reflection of CLCEs can be reversibly and dynamically tuned across the entire visible spectrum by mechanical stretching. Thanks to the introduction of dynamic boronic ester bonds, the CLCEs were found to show robust reprogrammable and self‐healing capabilities. The research disclosed herein can provide new insights into the development of 4D (color and 3D shape) programmable photonic actuators towards bioinspired camouflage, adaptive optical systems, and next‐generation intelligent machines.
Cholesteric liquid crystal elastomers (CLCEs) exhibiting mechanochromic, shape‐programmable and self‐healable properties were synthesized by introducing dynamic covalent boronic ester bonds into the main‐chain CLCE polymer networks. This research shines new light onto the development of dynamic covalent polymers for emerging applications in areas of bioinspired camouflage, adaptive optics and smart soft robotics.
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