The “2018 Chinese Guidelines for Prevention and Treatment of Hypertension”[1](hereinafter referred to as the 2018 Guidelines) published in this issue was revised by the Guidelines Revision Committee which is initiat...
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The “2018 Chinese Guidelines for Prevention and Treatment of Hypertension”[1](hereinafter referred to as the 2018 Guidelines) published in this issue was revised by the Guidelines Revision Committee which is initiated and organized by the Chinese Hypertension *** on the “2010 Chinese Guidelines for the Management of Hypertension” and recent evidence from domestic and international research in the field of hypertension,considering national conditions and the current situation of hypertension management in China,and reference to the latest European and American hypertension guidelines,the 2018 Guidelines make comprehensive and in-depth elaborations and recommendations of the diagnosis and assessment of hypertension,strategies and goals of prevention and treatment of hypertension and pathway of intervention,*** 2018 Guidelines not only provide Chinese medical personnel with guidance and reference for the clinical practice and population management of hypertension,but also serve as the latest textbook on updating concepts and knowledge in the field of hypertension.
A hybrid method of continuum and particle dynamics is developed for micro- and nano-fluidics, where fluids are described by a molecular dynamics （MD） in one domain and by the Navier-Stokes （NS） equations in anothe...
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A hybrid method of continuum and particle dynamics is developed for micro- and nano-fluidics, where fluids are described by a molecular dynamics （MD） in one domain and by the Navier-Stokes （NS） equations in another domain. In order to ensure the continuity of momentum flux, the continuum and molecular dynamics in the overlap domain are coupled through a constrained particle dynamics. The constrained particle dynamics is constructed with a virtual damping force and a virtual added mass force. The sudden-start Couette flows with either non-slip or slip boundary condition are used to test the hybrid method. It is shown that the results obtained are quantitatively in agreement with the analytical solutions under the non-slip boundary conditions and the full MD simulations under the slip bound- ary conditions.
The present experimental work is devoted to in- vestigate a new space-time correlation model for the turbulent boundary layer over a flat and a wavy walls. A turbulent boundary layer flow at Reo = 2460 is measured by ...
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The present experimental work is devoted to in- vestigate a new space-time correlation model for the turbulent boundary layer over a flat and a wavy walls. A turbulent boundary layer flow at Reo = 2460 is measured by tomographic time-resolved particle image velocimetry （Tomo-TRPIV）. The space-time correlations of instantaneous streamwise fluctuation velocity are calculated at 3 different wall-normal locations in logarithmic layer. It is found that the scales of coherent structure increase with moving far away from the wall. The growth of scales is a manifestation of the growth of prevalent coherent structures in the turbulent boundary layer like hairpin vortex or hairpin packets when they lift up. The resulting contours of the space-time correlation exhibit elliptic-like shapes rather than straight lines. It is suggested that, instead of Taylor hypothesis, the elliptic model of the space-time correlation is valid for the wallbounded turbulent flow over either a flat wall or a wavy wall. The elliptic iso-correlation curves have a uniform preferred orientation whose slope is determined by the convection velocity. The convection velocity derived from the space-time correlation represents the velocity at which the large-scale eddies carry small-scale eddies. The sweep velocity rep- resents the distortions of the small-scale eddies and is intimately associated with the fluctuation velocity in the logarithmic layer of turbulent boundary layers. The nondimensionalized correlation curves confirm that the elliptic model is more proper for approximating the space-time correlation than Taylor hypothesis, because the latter can not embody the small-scale motions which have non-negligible distortions. A second flow over a wavy wall is also recorded using TRPIV. Due to the combined effect of shear layers and the adverse pressure gradient, the space-time correlation does not show an elliptic-like shape at some specific heights over the wavy wall, but in the outer region of the wav
Because the aerospace-ground Internet no longer relies on deploying infrastructure such as base stations,it has the advantage of all-weather full coverage services that traditional terrestrial networks do not ***,the ...
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Because the aerospace-ground Internet no longer relies on deploying infrastructure such as base stations,it has the advantage of all-weather full coverage services that traditional terrestrial networks do not ***,the traditional global navigation satellite system does not support communication *** newly developing aerospace network system is still in the construction stage,and there is no applicable solution *** communication technology is an important method to solve the contradiction between the low battery capacity of the Internet of things(IoT)node and the high energy consumption of *** is the development trend of the ***,the current passive technology based on Wi-Fi and other signals cannot achieve arbitrary communication due to the excitation signal acquisition *** solve the above two major problems,this paper proposes a passive system design for aerospace-ground IoT *** system can use the global navigation signal as excitation signal for backscatter *** the global navigation signal has the characteristics of all-weather and full coverage,this design solves the carrier acquisition problem in previous *** addition,this paper also proposes a low-power signal detection technology that can detect navigation signals with high precision on passive *** evaluate system performance through simulation *** experimental results show that the backscatter system based on global navigation satellite signals can realize efficient communication of IoT nodes.
The spring snow cover(SC)over the western Tibetan Plateau(TP)(TPSC)(W_TPSC)and eastern TPSC(E_TPSC)have displayed remarkable decreasing and increasing trends,respectively,during 1985–*** current work investigates the...
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The spring snow cover(SC)over the western Tibetan Plateau(TP)(TPSC)(W_TPSC)and eastern TPSC(E_TPSC)have displayed remarkable decreasing and increasing trends,respectively,during 1985–*** current work investigates the possible mechanisms accounting for these distinct TPSC *** results indicate that the decrease in W_TPSC is primarily attributed to rising temperatures,while the increase in E_TPSC is closely linked to enhanced *** circulation analysis shows that the essential system responsible for the TPSC changes is a significant anticyclonic system centered over the northwestern *** anomalous descending motion and adiabatic heating linked to this anticyclone leads to warmer temperatures and consequent snowmelt over the western ***,anomalous easterly winds along the southern flank of this anticyclone serve to transport additional moisture from the North Pacific,leading to an increase in snowfall over the eastern *** analysis reveals that the anomalous anticyclone is associated with an atmospheric wave pattern that originates from upstream *** warming of the subtropical North Atlantic(NA)sea surface temperature(SST)induces an atmospheric pattern resembling a wave train that travels eastward across the Eurasian continent before reaching the ***,the decline in winter sea ice(SIC)over the Barents Sea exerts a persistent warming influence on the atmosphere,inducing an anomalous atmospheric circulation that propagates southeastward and strengthens the northwest TP anticyclone in ***,an enhancement of subtropical stationary waves has resulted in significant increases in easterly moisture fluxes over the coastal areas of East Asia,which further promotes more snowfall over eastern TP.
Iron sulfide is an attractive anode material for lithium-ion batteries (LIBs) due to its high specific capacity, environmental benignity, and abundant resources. However, its application is hindered by poor cyclabilit...
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Iron sulfide is an attractive anode material for lithium-ion batteries (LIBs) due to its high specific capacity, environmental benignity, and abundant resources. However, its application is hindered by poor cyclability and rate performance, caused by a large volume variation and low conductivity. Herein, iron sulfide porous nanowires confined in an N-doped carbon matrix (FeS@N-C nanowires) are fabricated through a simple amine-assisted solvothermal reaction and subsequent calcination strategy. The as-obtained FeS@N-C nanowires, as an LIB anode, exhibit ultrahigh reversible capacity, superior rate capability, and long-term cycling performance. In particular, a high specific capacity of 1,061 mAh·g−1 can be achieved at 1 A·g−1 after 500 cycles. Most impressively, it exhibits a high specific capacity of 433 mAh·g−1 even at 5 A·g−1. The superior electrochemical performance is ascribed to the synergistic effect of the porous nanowire structure and the conductive N-doped carbon matrix. These results demonstrate that the synergistic strategy of combining porous nanowires with an N-doped carbon matrix holds great potential for energy storage.
The single polycrystalline diamond compact(PDC)cutter test is widely used to investigate the mecha-nism of *** generated cuttings and cutting force are important indexes reflecting the rock failure ***,they were treat...
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The single polycrystalline diamond compact(PDC)cutter test is widely used to investigate the mecha-nism of *** generated cuttings and cutting force are important indexes reflecting the rock failure ***,they were treated as two separate parameters in previous *** this study,through a series of rock block cutting tests,the relationship between them was investigated to obtain an in-depth understanding of the formation of *** addition,to validate the standpoints obtained in the aforementioned experiments,rock sheet cutting tests were conducted and the rock failure process was monitored by a high-speed camera frame by *** cutting force was recorded with the same sampling rate as the *** this design,every sampled point of cutting force can match a picture captured by the camera,which reflects the interaction between the rock and the *** results indicate that the increase in cutting depth results in a transition of rock failure *** shallow cutting depth,ductile failure dominates and all the cuttings are produced by the compression of the *** corresponding cutting force fluctuates ***,beyond the critical depth,brittle failure occurs and chunk-like cuttings appear,which leads to a sharp decrease in cutting *** that,the generation of new surface results in a significant decrease in actual cutting depth,a parameter proposed to reflect the interaction between the rock and the ***,ductile failure dominates again and a slight fluctuation of cutting force can be *** the cutter moves to the rock,the actual cutting depth gradually increases,which results in the subsequent generation of chunk-like *** is accompanied by an obvious cutting force *** is,ductile failure and brittle failure,one following another,present at large cutting *** transition of rock failure mode can be correlated with the variation of cutting *** on the results of
A novel hydrochloride quaternary ammonium salt （E）-4-（benzyloxy）-2-（cinnamo- yloxy）-N,N,N-trimethyl-4-oxobutan-l-aminium chloride （Cz3HzgNO4Cl2, Mr = 454.37） has been synthesized via the sequence of acetylatio...
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A novel hydrochloride quaternary ammonium salt （E）-4-（benzyloxy）-2-（cinnamo- yloxy）-N,N,N-trimethyl-4-oxobutan-l-aminium chloride （Cz3HzgNO4Cl2, Mr = 454.37） has been synthesized via the sequence of acetylation and esterification by using L-carnitine （L-4-N-trimethy- lammonium-3-hydroxybutyric acid, LC） and cinnamic acid as the starting materials, and its crystal structure was determined by single-crystal X-ray diffraction method. The crystal belongs to monoclinic, space group P212121 with a = 10.1670（4）, b = 10.4488（4）, c = 22.9795（11）A, V = 2441.18（18）A3, Z = 4, Dc = 1.236 g/cm3,μ（MoKa） = 0.293 mm-1, F（000） = 960, Flack factor = -0.01（11）, the final R = 0.0489 and wR = 0.1550 for 3350 observed reflections （I 〉 2σ（/）） and R = 0.0953 for all 5648 unique reflections. The crystal structure involves a conjugated system which shows a reverse olefin structure.
Frequency is an important indicator for the oper-ation of ***,the randomness and uncertainty of renewable energy and load variability may lead to frequency ***,a robust load frequency control(LFC)is pro-posed for isol...
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Frequency is an important indicator for the oper-ation of ***,the randomness and uncertainty of renewable energy and load variability may lead to frequency ***,a robust load frequency control(LFC)is pro-posed for isolated wind-diesel microgrids considering time delay and parameter *** control strategy can suppress frequency fuctuation and optimize frequency dynamic ***,the double compensation loop,including feedforward control and integral sliding mode control(SMC),is devised to provide anti-disturbance compensation for the diesel generator system and ameliorate the frequency stability of independent ***,a dynamic fuzzy controller,composed of wind speed and load demand,is designed to provide real-time response reference power for doubly fed induction generator systems(DFIGs),which can promote the effective participation of a wind turbine system for frequency ***,the proportional differential(PD)parameters of a dynamic fuzzy controller and the frequency adjustment compensation of DFIGs can be obtained by using a particle swarm optimization(PSO)***,load demand is an important index of the robust dynamic load frequency control method;the radial basis function(RBF)neural network observer(NNO)based on the LFC model is presented to obtain more accurate load deviations and improve the control precision of *** performance of the proposed LFC method is tested under different operation *** Terms-Load frequency control,microgrid,neural network observer,sliding mode,time delay and parameter uncertainty.
作者：
Yunzhu weiSongbai ChenJiliang JingDepartment of Physics
Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of EducationInstitute of Interdisciplinary StudiesSynergetic Innovation Center for Quantum Effects and ApplicationsHunan Normal UniversityChangshaHunan 410081China Center for Gravitation and Cosmology
College of Physical Science and TechnologyYangzhou UniversityYangzhou 225009China
We have studied the equipotential surfaces of a thick accretion disk around a Casadio-Fabbri-Mazzacurati compact object in the brane-world scenario,which possesses a mass parameter together with a parameterized post-N...
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We have studied the equipotential surfaces of a thick accretion disk around a Casadio-Fabbri-Mazzacurati compact object in the brane-world scenario,which possesses a mass parameter together with a parameterized post-Newtonian(PPN)*** the increase in the PPN parameter,the size of the thick accretion disk decreases,but the corresponding Roche lobe size ***,the larger PPN parameter yields the larger region of existing bound disk structures,where the fluid is not accreted into the central ***,with the increase in the PPN parameter,the position of the Roche lobe gradually moves away from the central compact object,and the thickness of the region enclosed by the Roche lobe decreases near the compact object but increases in the region far from the compact *** results also show that the pressure gradient in the disk decreases with the PPN *** effects of the PPN parameter on the thick accretion disk could help one to further understand compact objects in the brane-world scenario.
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