Search

The recent proliferation of NISQ devices has made it imperative to understand their power. In this work, we define and study the complexity class NISQ, which encapsulates problems that can be efficiently solved by a classical computer with access to noisy quantum circuits. We establish super-polynomial separations in the complexity among classical computation, NISQ, and fault-tolerant quantum computation to solve some problems based on modifications of Simon's problems. We then consider the power of NISQ for three well-studied problems. For unstructured search, we prove that NISQ cannot achieve a Grover-like quadratic speedup over classical computers. For the Bernstein-Vazirani problem, we show that NISQ only needs a number of queries logarithmic in what is required for classical computers. Finally, for a quantum state learning problem, we prove that NISQ is exponentially weaker than classical computers with access to noiseless constant-depth quantum circuits. Our current understanding of the computational abilities of near-intermediate scale quantum (NISQ) computing devices is limited, in part due to the absence of a precise definition for this regime. Here, the authors formally define the NISQ realm and provide rigorous evidence that its capabilities are situated between the complexity classes BPP and BQP. [ABSTRACT FROM AUTHOR]

The iron-based friction material was prepared directly from vanadium-bearing titanomagnetite concentrates by in situ selective carbothermal reactions and vacuum sintering. In this study, drawing on the extraordinary properties of graphene, experiments were conducted to evaluate the effects of graphene additives with a range of 0.2 to 1.0 wt pct on the microstructure and properties of iron-based materials sintered at 1050 ∘ C for 3 hours. The graphene was added in the form of copper-coated graphene to solve the weak bonding between matrix and graphene. The results show that the microstructure and properties of iron-based friction materials with graphene are significantly improved, especially the iron-based material containing 0.8 wt pct graphene. The graphene reduces the lamellar spacing of pearlite and contributes a more uniform growth of the grain due to its considerable high thermal conductivity. In addition, graphene could also facilitate the austenite transformation to refine the grain. As a result, with the increasing of the graphene content, the hardness is enhanced while the wear rate and friction coefficient are decreased. Particularly, the oxide films on the worn surface are accumulated and transform from FeO to Fe3O4 and Fe2O3, together with the improved wear resistance, leading the wear behavior turns from severe abrasive and adhesive wear to mild abrasive wear. However, when the graphene content reaches to 1.0 wt pct, both the microstructure and tribological properties of the materials deteriorate again due to the aggregation of graphene. [ABSTRACT FROM AUTHOR]

The plants from genus Origanum are common folk Chinese herbs used to treat a variety of diseases. They are also used as a spice, a seasoning, and an ornament. Origanum plants are rich in essential oils and also have other compounds including terpenoids, flavonoids, organic acids, and sterols. They have a variety of biological activities such as antispasmodic, anti-inflammatory, growth-promoting, antibacterial, antioxidant, and anticancer properties. The chemical components and biological effects of genus Origanum were summarized by different scientific databases such as Web of Science, SciFinder, Baidu Scholar, PubMed, ScienceDirect, and SpringerLink. In conclusion, recent studies were mainly focused on the activities of their essential oils. The research studies for nonvolatile constituents and their pharmacological activities are few. Therefore, research on compounds in genus Origanum plants can be strengthened and their application prospect can be explored so as to make better use of the resources of these plants. [ABSTRACT FROM AUTHOR]

Flammulina velutipes is the fourth largest edible fungus in China with high nutritional value. In this paper, ultrahigh-performance liquid chromatography tandem hybrid quadrupole-Orbitrap mass spectrometry (UPLC-Q-Exactive-Orbitrap MS) was used to identify the secondary metabolites of F. velutipes. The metabolites were identified by comparing the retention time, accurate molecular weight, and MS2 data with standard databases of mzVault and mzCloud (compound: 17,000+) and BGI high-resolution accurate mass plant metabolome database (plant metabolite: 2500+). Finally, 26 secondary metabolites were preliminarily identified, including flavonoids, phenylpropanoids, organic acids, and steroids. [ABSTRACT FROM AUTHOR]

Poria is a common Traditional Chinese Medicine in clinic. In recent years, the chemical and pharmacological studies of Poria have made great progress, triterpenes and polysaccharides have been isolated, and various types of compounds containing lipids, octanoic acids, fatty acids, and trace elements have been found. In this paper, we reviewed the literature, summarized the main compound types, and reviewed in detail their pharmacological effects in antitumor, immunomodulatory, effects on kidney, hepatoprotective activity, effects on blood sugar, antioxidant effects, anti-inflammatory effects, effects on the gut, antidepressant, and so on, and also categorized the compounds with the same or similar pharmacological effects to provide a reference for the in-depth study of the material basis of the pharmacological effect, quality standards, and pharmacological activity of Poria. [ABSTRACT FROM AUTHOR]

Plants of Delphinium are herbal medicine used in the Tibet region with whole grass as a drug, which have the effects of analgesic, antibacterial, antipyretic, and anticancer. The main bioactive compounds are alkaloids, flavonoids, and sterols. This review summarized the compounds and pharmacological effects of Delphinium and provides a reference for further research on Delphinium. [ABSTRACT FROM AUTHOR]

The Collatz, or 3x + 1, Conjecture claims that for every positive integer n, there exists some k such that Tk(n) = 1, where T is the Collatz map. We present three cellular automata (CA) that transform the global prob-lem of mimicking the Collatz map in bases 2,3, and 4 into a local one of transforming the digits of iterates. The CAs streamline computation first by bypassing calculation of certain parts of trajectories: the binary CA bypasses division by two altogether. In addition, they allow for multiple trajectories to be calculated simultaneously, representing both a signif-icant improvement upon existing sequential methods of computing the Collatz map and a demonstration of the efficacy of using a massively parallel approach with cellular automata to tackle iterative problems like the Collatz Conjecture. [ABSTRACT FROM AUTHOR]

Ganoderma lucidum is widely used in traditional Chinese medicine (TCM). Ganoderic acid A and D are the main bioactive components with anticancer effects in G. lucidum. To obtain the maximum content of two compounds from G. lucidum, a novel extraction method, an ionic liquid-based ultrasonic-assisted method (ILUAE) was established. Ionic liquids (ILs) of different types and parameters, including the concentration of ILs, ultrasonic power, ultrasonic time, rotational speed, solid–liquid ratio, were optimized by the orthogonal experiment and variance analysis. Under these optimal conditions, the total extraction yield of the two compounds in G. lucidum was 3.31 mg/g, which is 36.21% higher than that of the traditional solvent extraction method. Subsequently, an artificial neural network (ANN) was developed to model the performance of the total extraction yield. The Levenberg–Marquardt back propagation algorithm with the sigmoid transfer function (logsig) at the hidden layer and a linear transfer function (purelin) at the output layer were used. Results showed that single hidden layer with 9 neurons presented the best values for the mean squared error (MSE) and the correlation coefficient (R), with respectively corresponding values of 0.09622 and 0.93332. [ABSTRACT FROM AUTHOR]

The microstructure and mechanical properties of brazing SiC ceramic with Zr-Cu filler metal under different brazing parameters (brazing temperature, holding time) were investigated. The phase of the joint reaction interface between Zr-Cu filler metal and SiC ceramic was characterized by XRD, the microstructure and fracture morphology of the brazing SiC ceramic joint were analyzed by SEM with EDS, and the strength of the joint was evaluated by compression shear test. The results show that the brazing join between SiC ceramic and Zr-Cu filler metal can be realized at the brazing temperature of 1100 °C~1300 °C, and the main products of interface reaction are ZrC and Zr2Si. The shear strength of the joint increases with the brazing temperature, and reaches the highest at 1200 °C. The thickness of interface reaction layer increases with the increase of holding time at brazing temperature of 1200 °C. Thickness of the interface reaction layer is 2.9 μm when the joint is holding for 20 min, and the maximum shear strength of the corresponding brazed SiC ceramic joint is 57 MPa. [ABSTRACT FROM AUTHOR]