We report phase-programmable Gaussian boson sampling (GBS) which produces up to 113 photon detection events out of a 144-mode photonic circuit. A new high-brightness and scalable quantum light source ...is developed, exploring the idea of stimulated emission of squeezed photons, which has simultaneously near-unity purity and efficiency. This GBS is programmable by tuning the phase of the input squeezed states. The obtained samples are efficiently validated by inferring from computationally friendly subsystems, which rules out hypotheses including distinguishable photons and thermal states. We show that our GBS experiment passes a nonclassicality test based on inequality constraints, and we reveal nontrivial genuine high-order correlations in the GBS samples, which are evidence of robustness against possible classical simulation schemes. This photonic quantum computer, Jiuzhang 2.0, yields a Hilbert space dimension up to ∼ 1043, and a sampling rate ∼ 1024 faster than using brute-force simulation on classical supercomputers.
Closed-loop supply chain network design (CLSCND) has been increasingly spotlighted over the latest decade. The focus has been given to maximize the economic performance, resource utilization and ...sustainability through incorporating a holistic decision-making on both forward and reverse logistics. In this paper, a new fuzzy-stochastic multi-objective mathematical model is formulated for sustainable CLSCND. The model aims at balancing the trade-off between cost effectiveness and environmental performance under different types of uncertainty. The environmental performance of CLSCND is measured by carbon emission. Moreover, the network flexibility is modeled and incorporated in the decision-making so that customer demands can be fulfilled by different means. In order to solve the complex optimization problem, the model is first defuzzilized and converted into an equivalent crisp form. Then, a sample average approximation based weighting method (SAAWM) is developed to obtain a set of Pareto optimal solutions between cost and carbon emission under different uncertain environments. The model is validated through a set of numerical experiments. The computational results show, through the incorporation with network flexibility, the proposed mathematical model and solution approach can effectively generate consistent objective values and solutions over different scenario trees and obtain robust strategic decisions on facility locations. Meanwhile, the flexibility and rationality of the decision-making on transportation management, demand allocation and facility operations can be improved as well.
•We formulate a new fuzzy-stochastic multi-objective model for sustainable design of a closed-loop supply chain.•We develop a new solution approach to solve the optimization problem.•We obtain both modelling and managerial implications from computational experiments.
Quantum computers promise to perform certain tasks that are believed to be intractable to classical computers. Boson sampling is such a task and is considered a strong candidate to demonstrate the ...quantum computational advantage. We performed Gaussian boson sampling by sending 50 indistinguishable single-mode squeezed states into a 100-mode ultralow-loss interferometer with full connectivity and random matrix-the whole optical setup is phase-locked-and sampling the output using 100 high-efficiency single-photon detectors. The obtained samples were validated against plausible hypotheses exploiting thermal states, distinguishable photons, and uniform distribution. The photonic quantum computer,
, generates up to 76 output photon clicks, which yields an output state-space dimension of 10
and a sampling rate that is faster than using the state-of-the-art simulation strategy and supercomputers by a factor of ~10
.
Hybrid organic–inorganic perovskites have attracted substantial interest as the most favorable prospective material for efficient photovoltaic and optoelectronic devices. However, their extreme ...sensitivity to electron beam radiation makes it difficult to obtain their intrinsic structure by transmission electron microscopy and can even lead to significant misidentifications. In 2018, the coexistence of methylammonium lead iodide (MAPbI3) in the cubic and tetragonal phase using electron microscopy and electron diffraction techniques was reported in article “Self‐Organized Superlattice and Phase Coexistence inside Thin Film Organometal Halide Perovskite”. Herein, however, that claim is challenged by comparing their experimental data to simulated diffraction patterns and arguing that their perovskite samples may have been damaged due to excessive electron beam irradiation. Consequently, true phase coexistence was not observed in that previously reported work, rather merely the decomposition products of MAPbI3.
Clearly, (1Ē2), (112) planes exist in the electron diffraction pattern. ...П2), (112) planes are also present in HRTEM images under low electron dose2, selected-area electron diffraction (SAED)3,4 ...and X-ray diffraction (XRD)5-7 characterizations. Owing to lack of the corresponding in situ high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image in the original paper, it is impossible to prove that the higher-contrast spots are PbS quantum dots rather than PbI2 particles. If possible, it would also be better if they compared the particle size and size distribution of colloidal quantum dots and quantum dots in perovskite in the original paper. ...a low dose10-15 and low temperature2,13 can reduce the damage of electron-beam irradiation to perovskite, and may help to obtain the real structure of the quantum dots in perovskite solids.
Organic‐inorganic hybrid perovskites (OIHPs) have recently emerged as groundbreaking semiconductor materials owing to their remarkable properties. Transmission electron microscopy (TEM), as a very ...powerful characterisation tool, has been widely used in perovskite materials for structural analysis and phase identification. However, the perovskites are highly sensitive to electron beams and easily decompose into PbX2 (X = I, Br, Cl) and metallic Pb. The electron dose of general high‐resolution TEM is much higher than the critical dose of MAPbI3, which results in universal misidentifications that PbI2 and Pb are incorrectly labelled as perovskite. The widely existed mistakes have negatively affected the development of perovskite research fields. Here misidentifications of the best‐known MAPbI3 perovskite are summarised and corrected, then the causes of mistakes are classified and ascertained. Above all, a solid method for phase identification and practical strategies to reduce the radiation damage for perovskite materials have also been proposed. This review aims to provide the causes of mistakes and avoid misinterpretations in perovskite research fields in the future.
Levitated optomechanics has great potential in precision measurements, thermodynamics, macroscopic quantum mechanics, and quantum sensing. Here we synthesize and optically levitate silica ...nanodumbbells in high vacuum. With a linearly polarized laser, we observe the torsional vibration of an optically levitated nanodumbbell. This levitated nanodumbbell torsion balance is a novel analog of the Cavendish torsion balance, and provides rare opportunities to observe the Casimir torque and probe the quantum nature of gravity as proposed recently. With a circularly polarized laser, we drive a 170-nm-diameter nanodumbbell to rotate beyond 1 GHz, which is the fastest nanomechanical rotor realized to date. Smaller silica nanodumbbells can sustain higher rotation frequencies. Such ultrafast rotation may be used to study material properties and probe vacuum friction.
With the focus on sustainable development, the value recovery from End-of-Life (EOL) and End-of-Use (EOU) products has been given considerable attention by the whole society. Reverse logistics is the ...process for value recovery and re-creation through a series of activities, i.e., repair, remanufacturing, recycling and energy recovery. However, due to the stochastic reverse product flow, unstable quality of used products, and the price fluctuation of recycled and remanufactured products, the planning of a reverse logistics system is more complex compared with that of a forward supply chain. In this paper, we propose a two-stage stochastic bi-objective mixed integer programming model for the network design problem of a multi-product multi-echelon sustainable reverse logistics system under uncertainty, which aims at providing a set of Pareto solutions between profitability and environmental performance. Furthermore, due to the heterogeneous nature, the processing operations performed at remanufacturing and recycling centers for different products are by no means identical. Different from the previous modelling efforts derived from a genetic “capacitated location problem”, this paper considers the impact from the system flexibility on sustainable reverse logistics network design. Thus, the model is formulated in two parallel ways with either efficiency-focused non-flexible capacity or effectiveness-focused flexible capacity. The experimental analysis illustrates that increasing environmental requirement will decrease the profitability of the reverse logistics system, while, increasing flexibility may yield positive impacts on both economic and environmental performance when the efficiency loss is kept at a proper level.
•Incorporating flexibility in sustainable reverse logistics network design.•Formulating mathematical model for decision support under uncertainty.•Different solution methods were tested, compared and discussed.•Results were analyzed for providing managerial implications.
•Core-shell Ni@SiO2@CeO2 catalyst was successful fabricated.•The Ni@SiO2@CeO2 catalyst exhibited high MDR performance at low temperatures.•Bi-functional mechanism of MDR over the Ni@SiO2@CeO2 ...catalyst was discussed.•Carbon deposition was significantly reduced for MDR.
Low temperature methane dry reforming by Ni-based catalysts is an economic way to convert greenhouse gases of CH4 and CO2, but carbon deposition is a great challenge. Taking the advantage of mobile oxygen on CeO2, we synthesized a Ni@SiO2@CeO2 catalyst by coating ceria on surface of Ni@SiO2 to reduce carbon deposition. H2 temperature-programmed reduction, X-ray photoelectron spectra and oxygen temperature-programmed desorption demonstrated the high oxygen mobility from ceria in Ni@SiO2@CeO2 catalyst, which significantly reduced carbon deposition and enhanced stability of methane dry reforming reaction. Experimental results revealed that methane dry reforming performance was one and a half times higher, but carbon deposition was one half lower, over the Ni@SiO2@CeO2 catalyst than over the Ni@SiO2 catalyst. The strategy of ceria coating in reducing carbon deposition and enhancing reaction stability could also be applied to other heterogeneous reactions suffering carbon deposition.
Aconitine (AC) is well‐known as the main toxic ingredient and active compound of Aconitum species, of which several aconites are essential herbal medicines of Traditional Chinese Medicine (TCM) and ...widely applied to treat diverse diseases for their excellent anti‐inflammatory, analgesic, and cardiotonic effects. However, the cardiotoxicity and neurotoxicity of AC attracted a lot of attention and made it a favorite botanic poison in history. Nowadays, the narrow therapeutic window of AC limits the clinical application of AC‐containing herbal medicines; overdosing on AC always induces ventricular tachyarrhythmia and heart arrest, both of which are potentially lethal. But the underlying cardiotoxic mechanisms remained chaos. Recently, beyond its cardiotoxic effects, emerging evidence shows that low doses of AC or its metabolites could generate cardioprotective effects and are necessary to aconite's clinical efficacy. Consistent with TCM's theory that even toxic substances are powerful medicines, AC thus could not be simply identified as a toxicant or a drug. To prevent cardiotoxicity while digging the unique value of AC in cardiac pharmacology, there exists a huge urge to better know the characteristic of AC being a cardiotoxic agent or a potential heart drug. Here, this article reviews the advances of AC metabolism and focuses on the latest mechanistic findings of cardiac efficacy and toxicity of this aconite alkaloid or its metabolites. We also discuss how to prevent AC‐related cardiotoxicity, as well as the issues before the development of AC‐based medicines that should be solved, to provide new insight into the paradoxical nature of this ancient poison.
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