Preparation of β²‑Homologous Amino Acids Bearing Polar Side Chains via a Collective Synthesis Strategy

β-Homologous amino acids (βhAAs) are a valuable class of building blocks for novel analogues of bioactive peptides. Thus, practical methods to synthesize enantiopure βhAAs are desirable. We report the application of a collective synthesis strategy to prepare protected β2-homologous amino acids with polar side chains. In this approach, a core structure is constructed via proline-catalyzed Mannich reaction and subsequently derivatized to furnish more than one protected β2-homologous amino acid with a proteinogenic side chain

Response of Methylammonium Lead Iodide to External Stimuli and Caloric Effects from Molecular Dynamics Simulations

The power conversion efficiency for solar cells fabricated using organometal halide perovskites (OMHPs) has risen to more than 20% in a short span of time, making OMHPs promising solar materials for harnessing energy from sunlight. The hybrid perovskite architecture that consists of organic molecular cations and an inorganic lattice could also potentially serve as a robust platform for materials design to realize functionalities beyond photovoltaic applications. Taking methylammonium lead iodide (MAPbI3) as an example, we explore the response of organometal halide perovskites to various stimuli, using all-atom molecular dynamics simulations with a first-principles-based interatomic potential. We find that a large electric field is necessary to introduce a sizable molecular ordering at room temperature in unstrained MAPbI3. Molecular dipoles in epitaxially strained MAPbI3 are more susceptible to an electric field. We also report various caloric effects in MAPbI3. The adiabatic thermal change is estimated directly by introducing different driving fields in the simulations. We find that MAPbI3 exhibits both electrocaloric and mechanocaloric effects at room temperature. Local structural analysis reveals that the rearrangement of molecular cations in response to electric and stress fields is responsible for the caloric effects. The enhancement of caloric response could be realized through strain engineering and chemical doping

Preparation of β²‑Homologous Amino Acids Bearing Polar Side Chains via a Collective Synthesis Strategy

β-Homologous amino acids (βhAAs) are a valuable class of building blocks for novel analogues of bioactive peptides. Thus, practical methods to synthesize enantiopure βhAAs are desirable. We report the application of a collective synthesis strategy to prepare protected β2-homologous amino acids with polar side chains. In this approach, a core structure is constructed via proline-catalyzed Mannich reaction and subsequently derivatized to furnish more than one protected β2-homologous amino acid with a proteinogenic side chain

PADP: A parallel data possession audit model for cloud storage

PADP: A parallel data possession audit model for cloud storag

Three-Dimensional Activity Volcano Plot under an External Electric Field

An external electric field (EEF) can impact a broad range of catalytic processes beyond redox systems. Computational design of catalysts under EEFs targeting specific operation conditions essentially requires accurate predictions of the response of a complex physicochemical system to collective parameters such as EEF strength/direction and temperature. Here, we develop a multiscale approach that progressively bridges finite-field density functional theory, chemical reaction network theory, microkinetic modeling, and machine learning-assisted high-throughput computations, which leads to the construction of a three-dimensional activity volcano plot under EEFs for thousands of metallic alloys. Taking steam reforming of methanol as an example, we discover a nontrivial collective effect of EEF and temperature on the conversion of methanol: a positive EEF can increase the conversion at high temperatures but strongly suppress the conversion at low temperatures, highlighting the necessity of multiscale modeling for catalyst design under EEFs

The structure of hydraulic wave energy power generation system.

The structure of hydraulic wave energy power generation system.</p

Feinberg_OnlineAppendix – Supplemental material for A World of Blame to Go Around: Cross-Cultural Determinants of Responsibility and Punishment Judgments

Supplemental material, Feinberg_OnlineAppendix for A World of Blame to Go Around: Cross-Cultural Determinants of Responsibility and Punishment Judgments by Matthew Feinberg, Ray Fang, Shi Liu and Kaiping Peng in Personality and Social Psychology Bulletin</p

The topology structure of the power generation system.

The topology structure of the power generation system.</p

Wave diagram under different conditions.

(a) Hs = 1m, Tp = 3s, (b) Hs = 2m, Tp = 5s, and (c) Hs = 3m, Tp = 6s.</p

Hydraulic cylinder structure.

Wave energy is one of the primary sources of marine energy, representing a readily available and inexhaustible form of renewable clean energy. In recent years, wave energy generation has garnered increasing attention from researchers. To study wave energy generation technology, we have constructed a real wave energy generation system and designed wave simulation and hydraulic energy storage systems. The wave simulation system is mainly composed of a frequency converter and an electric boost pump, while the hydraulic energy storage system consists of a hydraulic control unit and hydraulic motors. Corresponding mathematical models have been established to investigate the characteristics of wave energy generation. Specifically, a mathematical model for wave input using the double-parameter JONSWAP wave spectrum has been created for wave simulation in the wave simulation system. For the hydraulic energy storage system, known as the Power Take Off (PTO) system, mathematical models have been developed for double-acting hydraulic cylinders, energy storage devices, and precise displacement hydraulic motors, taking into consideration fluid Reynolds numbers and leakage. During the generation of wave energy, there is a problem of prolonged power interruption when wave conditions are unfavorable, which hinders continuous power generation. To address this issue, a system structure with an energy storage unit and two parallel generator sets, as well as a power operation optimization scheme, have been proposed. This system structure and optimization approach efficiently and reasonably utilize wave energy, achieving the goal of uninterrupted power supply in the hydraulic wave energy generation system.</div