Demonstration and Operation of Quantum Harmonic Oscillators in AlGaAs/GaAs Heterostructure

The quantum harmonic oscillator (QHO), one of the most important and ubiquitous model systems in quantum mechanics, features equally spaced energy levels or eigenstates. Here we report on the design, demonstration and operation of nearly perfect QHOs in AlGaAs/GaAs heterostructure. On the basis of model calculations, we demonstrate that, when a substitutional Si donor substitutes the Ga/Al lattice site close to AlGaAs/GaAs heterointerface, a hydrogenic Si QHO, characterized by a restoring Coulomb force producing square law harmonic potential, is formed. This gives rise to QHO states with energy spacing of ~8-9 meV. We experimentally confirm this proposal by utilizing Stark effect and measuring QHO states using an aluminum single-electron transistor (SET). A sharp and fast oscillation with period of ~7-8 mV appears in addition to the regular Coulomb blockade (CB) oscillation with much larger period, for positive gate biases above 0.5 V. The observation of fast oscillation and its behavior is qualitatively consistent with our theoretical result, manifesting the harmonic motion of electrons from the QHO. Our results might establish a general principle to design, construct and manipulate QHOs in semiconductor heterostructures.Comment: 17 pages, 4 figure

Numerical Simulation Study on Propeller Slipstream Interference of High Altitude Long Endurance Unmanned Air Vehicle

AbstractIn this paper,thecontrol equation of Multiple Reference Frame(MRF) as the propeller calculation model was present and analyzed, the propeller slipstream interference on HALE UAV was studied with three-dimensional numerical simulation. It is shown that the flow field of the MRF model is good consistent with true propeller flow, and MRF can accurately simulate aerodynamic interference on the aircraft. The stream traces on the V-tail surface were deflected and shrank, pressure distribution,Cmx and Cmzon V-tail surface was changed apparently too.Butslipstream had little effect on wing. The influence of propeller slipstream on the aerodynamic performance of the UAV at the status of taking off is biggest, become weaker at status of climbing and smallest at the status of cruising. The influence of propeller slipstream is enhanced with increment of propeller thrust and basically familiar in the same thrust between the two blade attack angle. The pressure drag on aft of UAV fuselage increased rapidly by the interference of propeller slipstream, leading aerodynamic performance of UAV become badly

Water-Soluble 3D Covalent Organic Framework that Displays an Enhanced Enrichment Effect of Photosensitizers and Catalysts for the Reduction of Protons to H2.

Covalent organic frameworks (COFs) are emerging porous polymers that have 2D or 3D long-range ordering. Currently available COFs are typically insoluble or decompose upon dissolution, which remarkably restricts their practical implementations. For 3D COFs, the achievement of noninterpenetration, which maximizes their porosity-derived applications, also remains a challenge synthetically. Here, we report the synthesis of the first highly water-soluble 3D COF (sCOF-101) from irreversible polymerization of a preorganized supramolecular organic framework through cucurbit[8]uril (CB[8])-controlled [2 + 2] photodimerization. Synchrotron X-ray scattering and diffraction analyses confirm that sCOF-101 exhibits porosity periodicity, with a channel diameter of 2.3 nm, in both water and the solid state and retains the periodicity under both strongly acidic and basic conditions. As an ordered 3D polymer, sCOF-101 can enrich [Ru(bpy)3]2+ photosensitizers and redox-active polyoxometalates in water, which leads to remarkable increase of their photocatalytic activity for proton reduction to produce H2

Topological dissipative Kerr soliton combs in a valley photonic crystal resonator

Topological phases have become an enabling role in exploiting new applications of nonlinear optics in recent years. Here we theoretically propose a valley photonic crystal resonator emulating topologically protected dissipative Kerr soliton combs. It is shown that topological resonator modes can be observed in the resonator. Moreover, we also simulate the dynamic evolution of the topological resonator with the injection of a continuous-wave pump laser. We find that the topological optical frequency combs evolve from Turing rolls to chaotic states, and eventually into single soliton states. More importantly, such dissipative Kerr soliton combs generated in the resonator are inborn topologically protected, showing robustness against sharp bends and structural disorders. Our design supporting topologically protected dissipative Kerr soliton combs could be implemented experimentally in on-chip nanofabricated photonic devices.Comment: 16 pages, 12 figure

Identification of BST2 Contributing to the Development of Glioblastoma Based on Bioinformatics Analysis

Rigorous molecular analysis of the immune cell environment and immune response of human tumors has led to immune checkpoint inhibitors as one of the most promising strategies for the treatment of human cancer. However, in human glioblastoma multiforme (GBM) which develops in part by attracting immune cell types intrinsic to the human brain (microglia), standard immunotherapy has yielded inconsistent results in experimental models and patients. Here, we analyzed publicly available expression datasets to identify molecules possibly associated with immune response originating from or influencing the tumor microenvironment in primary tumor samples. Using three glioma datasets (GSE16011, Rembrandt-glioma and TCGA-glioma), we first analyzed the data to distinguish between GBMs of high and low tumor cell purity, a reflection of the cellular composition of the tumor microenvironment, and second, to identify differentially expressed genes (DEGs) between these two groups using GSEA and other analyses. Tumor purity was negatively correlated with patient prognosis. The interferon gamma-related gene BST2 emerged as a DEG that was highly expressed in GBM and negatively correlated with tumor purity. BST2high tumors also tended to harbor PTEN mutations (31 vs. 9%, BST2high versus BST2low) while BST2low tumors more often had sustained TP53 mutations (8 versus 36%, BST2high versus BST2low). Prognosis of patients with BST2high tumors was also poor relative to patients with BST2low tumors. Further molecular in silico analysis demonstrated that high expression of BST2 was negatively correlated with CD8+ T cells but positively correlated with macrophages with an M2 phenotype. Further functional analysis demonstrated that BST2 was associated with multiple immune checkpoints and cytokines, and may promote tumorigenesis and progression through interferon gamma, IL6/JAK/STAT3 signaling, IL2/STAT5 signaling and the TNF-α signaling via NF-kB pathway. Finally, a series of experiments confirmed that the expression of BST2 can be significantly increased by IFN induction, and knockdown of BST2 can significantly inhibit the growth and invasion of GBM cells, and may affect the phenotype of tumor-associated macrophages. In conclusion, BST2 may promote the progression of GBM and may be a target for treatment.publishedVersio

Development and application of a three-dimensional simulation test system for directional regional grouting

Directional regional grouting to transform aquifers is one of the effective ways to prevent and control mine water hazards. In order to study the diffusion law of grouting slurry in directional areas, a three-dimensional simulation test system for directional area grouting has been independently developed. The system is mainly composed of test bench, grouting system, water injection system, data monitoring and other subsystems, which can realize directional drilling grouting simulation, three-dimensional slurry diffusion simulation, high pressure water simulation and regional grouting simulation. The system can independently control the grouting hole unit to achieve porous and multi sequence grouting. With the help of six grouting holes, the slurry flow process is simulated under various parameters such as different grouting pressure, slurry viscosity, grouting rate, and water cement ratio. It can also achieve real-time monitoring of the slurry diffusion process in dynamic/static (high) water pressure environments. The paper takes the simulated naked hole lengths of 200 mm, 250 mm, and 300 mm as the research objects, and preliminarily explores the characteristics and effects of slurry diffusion in naked hole grouting under directional grouting. The study found that: in the case where only the naked hole length is a variable, the slurry diffusion range does not synchronously increase linearly with the linear increase of naked hole length; The slurry stone body of the short open hole is cylindrical with the drilling open hole as the axis, while the slurry stone body of the long open hole is circular with the drilling open hole as the axis; Increasing the same length of the bare hole results in a larger difference in the diffusion range of the slurry at both ends of the bare hole. At the same time, the more pressure loss there is, the smaller the diffusion distance of the slurry. Comparing the diffusion radius of the slurry obtained from the experiment with that calculated by the Maag formula, the difference between the two values is only 2.8% when the length of the grouting open hole is 200 mm. The experimental results comply with the Maag spherical diffusion theory and verified the scientificity and rationality of this experimental system

AsterixDB: A Scalable, Open Source BDMS

AsterixDB is a new, full-function BDMS (Big Data Management System) with a feature set that distinguishes it from other platforms in today's open source Big Data ecosystem. Its features make it well-suited to applications like web data warehousing, social data storage and analysis, and other use cases related to Big Data. AsterixDB has a flexible NoSQL style data model; a query language that supports a wide range of queries; a scalable runtime; partitioned, LSM-based data storage and indexing (including B+-tree, R-tree, and text indexes); support for external as well as natively stored data; a rich set of built-in types; support for fuzzy, spatial, and temporal types and queries; a built-in notion of data feeds for ingestion of data; and transaction support akin to that of a NoSQL store. Development of AsterixDB began in 2009 and led to a mid-2013 initial open source release. This paper is the first complete description of the resulting open source AsterixDB system. Covered herein are the system's data model, its query language, and its software architecture. Also included are a summary of the current status of the project and a first glimpse into how AsterixDB performs when compared to alternative technologies, including a parallel relational DBMS, a popular NoSQL store, and a popular Hadoop-based SQL data analytics platform, for things that both technologies can do. Also included is a brief description of some initial trials that the system has undergone and the lessons learned (and plans laid) based on those early "customer" engagements