9,740 research outputs found
Pertusadina metcalfii, a new combination in Chinese Rubiaceae
No full textPertusadina hainanensis (F.C. How) Ridsdale is replaced by Pertusadina metcalfii (Merr. ex H.L.
Li) Y.F. Deng & C.M. Hu
Performance Evaluation of Distributed-Antenna Communications Systems Using Beam-Hopping
No full textDigital beamforming (DBF) techniques are capable of improving the performance of communications systems significantly. However, if the transmitted signals are conflicted with strong interference, especially, in the direction of the transmitted beams , these directional jamming signals will severely degrade the system performance. In order to efficiently mitigate the interference of the directional jammers, in this contribution a beam-hopping (BH) communications scheme is proposed. In the proposed BH communications scheme, only one pair of the beams is used for transmission and it hops from one to the next according to an assigned BH pattern. In this contribution a range of expressions in terms of the average SINR performance have been derived, when both the uplink and downlink are considered. The average SINR performance of the proposed BH scheme and that of the conventional single-beam (SB) as well as multiple-beam (MB) assisted beam-processing schemes have been investigated. Our analysis and results show that the proposed BH scheme is capable of efficiently combating the directional jamming, with the aid of utilizing the directional gain of the beams generated by both the transmitter and the receiver. Furthermore, the BH scheme is capable of reducing the intercept probability of the communications. Therefore, the proposed BH scheme is suitable for communications, when several distributed antenna arrays are available around a mobile
Factors that influence physicians in providing palliative care in rural communities in Taiwan.
No full textTun hu: (du mu ju ji).
No full text復工之前 -- 母女們 -- 囤戶.吳天著.Drama.Wu Tian zhu.Fu gong zhi qian -- Mu nü men -- Tun hu
A new cohesive model for simulating delamination propagation in composite laminates under transverse loads
No full textIn this paper, we propose a new cohesive model to stably and accurately simulate the\ud
delamination propagations in composite laminates under quasi-static and low-velocity\ud
impact transverse loads using comparatively coarse meshes. In this model, a pre-softening\ud
zone ahead of the existing traditional softening zone is proposed. In this pre-softening zone,\ud
the initial stiffnesses and the interface strengths at the integration points of cohesive elements\ud
are gradually reduced as the corresponding effective relative displacements at these\ud
points increase. However, the onset displacement corresponding to the onset damage is\ud
not changed in this model. Moreover, the fracture toughness of materials for determining\ud
the final displacement of complete decohesion is kept constant. This cohesive model is\ud
implemented in the explicit time integration scheme combined with a powerful threedimensional\ud
(3D) hybrid finite element for evaluating the delamination propagations on\ud
interfaces in composite laminates. A DCB problem is employed to analyze the characteristics\ud
of the present cohesive model. In order to reduce the computational cost for dealing\ud
with more complex problems, a stress-based criterion is also adopted in our numerical\ud
model for evaluating various in-plane damages, such as matrix cracks, fiber breakage,\ud
etc. Finally, two experimental examples are employed to illustrate the validity of the present\ud
approach
Flow dynamics on a U shaped channel flow: a numerical study
No full textThe paper deals with the numerical simulation of river channel flows at laboratory scale. The adopted geometry
consists of a U shaped trapezoidal smooth open channel with fixed slope. The branches, 3m of length each, are linked with a joint, 0.40m long, realizing two 90 degrees bends. The system is fed upstream with a water discharge under critical conditions while a Cipolletti weir is set downstream to control flow profiles.
Steady flow movements are obtained by means of two different softwares: a pure Lagrangian developed by the author, based on the Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) technique and Flow3D®, a commercial CFD software based on a Finite Volume formulation of the Navier Stokes equations in the Eulerian framework. Depending on the assumed boundary conditions, velocity profiles and water interfaces at certain cross sections are deducted by using the codes. Results are discussed and compared, showing a satisfactory agreement
Broadband satellite multimedia
No full textThe broadband satellite multimedia (BSM) architecture standardised by ETSI defines a satellite independent service access point (SI-SAP) interface layer that separates the satellite independent features of the upper layers from the satellite dependant features of the lower layers, and provides a mechanism to carry IP-based protocols over these satellite dependent lower layers. This enables interoperability at the IP layer between satellite systems of different physical and link layers technologies that fully comply with the SI-SAP concept. This study reviews past and current standardisation activities including the BSM quality of service (QoS) architecture, security architecture, network management that have been carried out by the ETSI Technical Committee-Satellite Earth Stations and Systems (TC-SES)/BSM working group and looking into the future to extend current SI-SAP functions that can enhance existing QoS provision and security management
capabilities as well as proposing a mobility management architecture that complies with the IEEE 802.21 media independent handover framework to support BSM mobility and to allow integration of satellite networks with fixed and mobile network infrastructures. A service-based network management architecture is also proposed to allow management flexibility and integration of business and operation support functions, paving the way for satellite integration into the Internet of the future
HU Protein Induces Incoherent DNA Persistence Length
No full textHU is a highly conserved protein that is believed to play an important role in the architecture and dynamic compaction of bacterial DNA. Its ability to control DNA bending is crucial for functions such as transcription and replication. The effects of HU on the DNA structure have been studied so far mainly by single molecule methods that require us to apply stretching forces on the DNA and therefore may perturb the DNA-protein interaction. To overcome this hurdle, we study the effect of HU on the DNA structure without applying external forces by using an improved tethered particle motion method. By combining the results with DNA curvature analysis from atomic force microscopy measurements we find that the DNA consists of two different curvature distributions and the measured persistence length is determined by their interplay. As a result, the effective persistence length adopts a bimodal property that depends primarily on the HU concentration. The results can be explained according to a recently suggested model that distinguishes single protein binding from cooperative protein binding.Imaging Science and TechnologyApplied Science
Systematics of a Kleptoplastidal Dinoflagellate, Gymnodinium eucyaneum Hu (Dinophyceae), and Its Cryptomonad Endosymbiont
No full textNew specimens of the kleptoplastidal dinoflagellate Gymnodinium eucyaneum Hu were collected in China. We investigated the systematics of the dinoflagellate and the origin of its endosymbiont based on light morphology and phylogenetic analyses using multiple DNA sequences. Cells were dorsoventrally flattened with a sharply acute hypocone and a hemispherical epicone. The confusion between G. eucyaneum and G. acidotum Nygaard still needs to be resolved. We found that the hypocone was conspicuously larger than the epicone in most G. eucyaneum cells, which differed from G. acidotum, but there were a few cells whose hypocone and epicone were of nearly the same size. In addition, there was only one site difference in the partial nuclear LSU rDNA sequences of a sample from Japan given the name G. acidotum and G. eucyaneum in the present study, which suggest that G. eucyaneum may be a synonym of G. acidotum. Spectroscopic analyses and phylogenetic analyses based on nucleomorph SSU rDNA sequences and chloroplast 23 s rDNA sequences suggested that the endosymbiont of G. eucyaneum was derived from Chroomonas (Cryptophyta), and that it was most closely related to C. coerulea Skuja. Moreover, the newly reported kleptoplastidal dinoflagellates G. myriopyrenoides and G. eucyaneum in our study were very similar, and the taxonomy of kleptoplastidal dinoflagellates was discussed.New specimens of the kleptoplastidal dinoflagellate Gymnodinium eucyaneum Hu were collected in China. We investigated the systematics of the dinoflagellate and the origin of its endosymbiont based on light morphology and phylogenetic analyses using multiple DNA sequences. Cells were dorsoventrally flattened with a sharply acute hypocone and a hemispherical epicone. The confusion between G. eucyaneum and G. acidotum Nygaard still needs to be resolved. We found that the hypocone was conspicuously larger than the epicone in most G. eucyaneum cells, which differed from G. acidotum, but there were a few cells whose hypocone and epicone were of nearly the same size. In addition, there was only one site difference in the partial nuclear LSU rDNA sequences of a sample from Japan given the name G. acidotum and G. eucyaneum in the present study, which suggest that G. eucyaneum may be a synonym of G. acidotum. Spectroscopic analyses and phylogenetic analyses based on nucleomorph SSU rDNA sequences and chloroplast 23 s rDNA sequences suggested that the endosymbiont of G. eucyaneum was derived from Chroomonas (Cryptophyta), and that it was most closely related to C. coerulea Skuja. Moreover, the newly reported kleptoplastidal dinoflagellates G. myriopyrenoides and G. eucyaneum in our study were very similar, and the taxonomy of kleptoplastidal dinoflagellates was discussed
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