957 research outputs found

    Bis(2,4-dibromo-6-formyl­phenolato-κ2 O,O′)copper(II)

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    In the title compound, [Cu(C7H3Br2O2)2], the CuII atom, which lies on an inversion centre, is coordinated by four O atoms from two chelating bidentate 2,4-dibromo-6-formyl­phenolate ligands in a slightly distorted square-planar coordination geometry. In the crystal structure, short inter­molecular Br⋯Br [3.516 (4) and 3.653 (4) Å] and Cu⋯Br [3.255 (1) Å] contacts together with C—H⋯O hydrogen bonds generate a three-dimensional network

    An Adaptive Dynamic Surface Controller for Ultralow Altitude Airdrop Flight Path Angle with Actuator Input Nonlinearity

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    In the process of ultralow altitude airdrop, many factors such as actuator input dead-zone, backlash, uncertain external atmospheric disturbance, and model unknown nonlinearity affect the precision of trajectory tracking. In response, a robust adaptive neural network dynamic surface controller is developed. As a result, the aircraft longitudinal dynamics with actuator input nonlinearity is derived; the unknown nonlinear model functions are approximated by means of the RBF neural network. Also, an adaption strategy is used to achieve robustness against model uncertainties. Finally, it has been proved that all the signals in the closed-loop system are bounded and the tracking error converges to a small residual set asymptotically. Simulation results demonstrate the perfect tracking performance and strong robustness of the proposed method, which is not only applicable to the actuator with input dead-zone but also suitable for the backlash nonlinearity. At the same time, it can effectively overcome the effects of dead-zone and the atmospheric disturbance on the system and ensure the fast track of the desired flight path angle instruction, which overthrows the assumption that system functions must be known

    SjTPdb: integrated transcriptome and proteome database and analysis platform for Schistosoma japonicum

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    <p>Abstract</p> <p>Background</p> <p><it>Schistosoma japonicum </it>is one of the three major blood fluke species, the etiological agents of schistosomiasis which remains a serious public health problem with an estimated 200 million people infected in 76 countries. In recent years, enormous amounts of both transcriptomic and proteomic data of schistosomes have become available, providing information on gene expression profiles for developmental stages and tissues of <it>S. japonicum</it>. Here, we establish a public searchable database, termed SjTPdb, with integrated transcriptomic and proteomic data of <it>S. japonicum</it>, to enable more efficient access and utility of these data and to facilitate the study of schistosome biology, physiology and evolution.</p> <p>Description</p> <p>All the available ESTs, EST clusters, and the proteomic dataset of <it>S. japonicum </it>are deposited in SjTPdb. The core of the database is the 8,420 <it>S. japonicum </it>proteins translated from the EST clusters, which are well annotated for sequence similarity, structural features, functional ontology, genomic variations and expression patterns across developmental stages and tissues including the tegument and eggshell of this flatworm. The data can be queried by simple text search, BLAST search, search based on developmental stage of the life cycle, and an integrated search for more specific information. A PHP-based web interface allows users to browse and query SjTPdb, and moreover to switch to external databases by the following embedded links.</p> <p>Conclusion</p> <p>SjTPdb is the first schistosome database with detailed annotations for schistosome proteins. It is also the first integrated database of both transcriptome and proteome of <it>S. japonicum</it>, providing a comprehensive data resource and research platform to facilitate functional genomics of schistosome. SjTPdb is available from URL: <url>http://function.chgc.sh.cn/sj-proteome/index.htm</url>.</p

    Heavy flavor quenching and flow: the roles of initial condition, pre-equilibrium evolution and in-medium interaction

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    Within an advanced Langevin-hydrodynamics framework coupled to a hybrid fragmentation-coalescence hadronization model, we study heavy flavor quenching and flow in relativistic heavy-ion collisions. We investigate how the initial heavy quark spectrum, the energy loss and hadronization mechanisms of heavy quarks in medium, the evolution profile of pre-equilibrium stage, the flow of medium and the temperature dependence of heavy quark diffusion coefficient influence the suppression and elliptic flow of heavy mesons at RHIC and the LHC. Our result shows that different modeling of initial conditions, pre-equilibrium evolution and in-medium interaction can individually yield about 10-40% uncertainties in D meson suppression and flow at low transverse momentum. We also find that a proper combination of collisional versus radiative energy loss, coalescence versus fragmentation in hadronization, and the inclusion of medium flow are the most important factors for describing the suppression and elliptic flow of heavy mesons.Comment: 9 pages, 7 figures; to be published in Chinese Physics

    Widespread subsonic turbulence in Ophiuchus North 1

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    Supersonic motions are common in molecular clouds. (Sub)sonic turbulence is usually detected toward dense cores and filaments. However, it remains unknown whether (sub)sonic motions at larger scales (≳\gtrsim1~pc) can be present in different environments or not. Located at a distance of about 110 pc, Ophiuchus North 1 (Oph N1) is one of the nearest molecular clouds that allows in-depth investigation of its turbulence properties by large-scale mapping observations of single-dish telescopes. We carried out the 12^{12}CO (J=1−0J=1-0) and C18^{18}O (J=1−0J=1-0) imaging observations toward Oph N1 with the Purple Mountain Observatory 13.7 m telescope. The observations have an angular resolution of ∼\sim55\arcsec (i.e., 0.03~pc). Most of the whole C18^{18}O emitting regions have Mach numbers of ≲\lesssim1, demonstrating the large-scale (sub)sonic turbulence across Oph N1. Based on the polarization measurements, we estimate the magnetic field strength of the plane-of-sky component to be ≳\gtrsim9~μ\muG. We infer that Oph N1 is globally sub-Alfv{\'e}nic, and is supported against gravity mainly by the magnetic field. The steep velocity structure function can be caused by the expansion of the Sh~2-27 H{\scriptsize II} region or the dissipative range of incompressible turbulence. Our observations reveal a surprising case of clouds characterised by widespread subsonic turbulence and steep size-linewidth relationship. This cloud is magnetized where ion-neutral friction should play an important role.Comment: 16 pages, 12 figures, accepted for publication in A&
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