最新刊期
卷 52 ， 期 3 ， 2013
- 摘要：A creative concept of uniqueness logic is proposed and defined. Uniquenss logic is used to determine whether a unique component exists in an input vector. Possible prospects for the applications of uniqueness logic are presented. BP neural network is employed to construct the uniqueness detection and application models. Computer experiments show that the models based on BP neural network can realize the dectection and application of uniqueness logic accurately and effectively.关键词：neural network;back propagation;uniqueness logic;detection model
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发布时间：2023-12-11 - 摘要：By removing the sericin from the silk fibers using Na2CO3solution, bio-fibers in diameters of 5~15 μm were fabricated and their morphology was observed using SEM and TEM. With the method of evanescent wave coupling, red/green/blue light at the wavelength of 671/532/473 nm was coupled into the micrometer-sized silk fiber-based optical fibers, followed by the investigation of the waveguiding properties and measurement of the optical propagating loss. Various photonic devices, including 2×2, 3×1, 1×4 and ring structures, were fabricated using the silk fibers. Experimental results confirm that the silk fiber-based bio-optical fibers exhibit good flexibility and surface smoothness. A propagating loss of 0.78 dB·mm-1was obtained for the green light at 532 nm guided in the silk fiber with diameter of 9.0 μm.关键词：optical device;micro/nano bio-optical fiber;evanescent wave coupling;silk fiber
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发布时间：2023-12-11 - 摘要：For the separation problem of bridge deflection monitoring, a precise method of separation deflection is presented using sigular value decomposition principle according to the periodic characteristics of the bridge deflection. Experimental and analytical results show that the method separate the various deflection components from the long term monitoring deflection,and the separation effect of temperature deflection with the periodic characteristics was good specially from the long term monitoring deflection.A new and precise method of separation deflection is provided.关键词：sigular value decomposition;bridge deflection;separation;temperature effect
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发布时间：2023-12-11 - 摘要：According to the defect of the embankment due to the river scour effect, a coupling analysis method of the river scour prediction and the slope stability analysis is established. First, based on the neural network method, the deformation prediction of the embankment and riverbed with river scour effect are made and the geometric shape of the embankment slope toe after the river scour is got. Then，the stability analysis and the stressstrain analysis of the slope are carried on to get the overall stability evaluation and the deformation features of the embankment with river scour effect. The established model and the efficiency of the adopted method have been verified by the calculate of the typical section of the BeiJiang embankment. It has important theoretical basis and practical value for the operation management of the important manmade embankment.关键词：slope stability;river scour;neural network;man-made embankment;overall stability
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发布时间：2023-12-11 - 摘要：Porous structures have the property of diminishing wave loads. Based on first order cnoidal wave theory and Biot consolidation theory, the mathematical solutions are derived for shallow water wave diffracted pressure and waveinduced seepage pressure on a porous vertical circular cylinder resting on porous elastic seabed in shallow water, and direct wave force and moment and waveinduced uplift force and overturn moment on the circular cylinder are correspondingly evaluated. The result shows that the variation of ocean condition and structure parameter have different effects on various wave loads， the magnitude of wave-induced seepage loads may have same order of horizontal wave loads, and the permeability of the cylinder surface will lead an obvious reduction in direct wave effects on cylinder and certain reduction in seepage overturn moment on the bottom of cylinder. Furthermore, the suitable choice of the ratio of the cylinders inside diameter to outside diameter may lead effects of both diminishing wave loads and ensuring stability of circular cylinder. Compared with the results from Airy wave theory, the wave load prediction values from shallow water wave theories can reflect wave nonlinearity effects.关键词：cnoidal wave;diffraction;radiation;wave force;wave-induced seepage force
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发布时间：2023-12-11 - 摘要：At present, utilizing Compressed Sensing(CS) theory to improve image quality of reconstructions is a research focus of image process technology. By deploying blockbased CS variable sampling within the domain of a wavelet transform, a multiscale blockCS algorithm with smoothed projected Landweber reconstruction algorithm is provided. Blockbased CS sampling is applied independently within each subband of each decomposition level of a wavelet transform of a image. Experimental results reveal that the algorithm achieves a 1~3 dB gain in reconstruction PSNR over the BCS-SPL and TV as well as multiscale GPSR algorithm.关键词：multiscale;DWT;compressed sensing;variable sampling rate;reconstruction
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发布时间：2023-12-11 - 摘要：In order to implement the highefficiency velocity control of AC permanent magnet synchronous motors, a fractionalorder PD controller satisfying the system stability and robustness is proposed. Then, for the purpose of evaluating the performance of the controller, a comparison between the designed controller and the conventional optimal integerorder PI controller is made via simulations and prototype experiments. The results show that the designed fractionalorder PD controller outperforms the optimal integerorder PI controller in response speed and tracking performance, and energysaving efficiency.关键词：fractional order PD controller;integer order PI controller;PMSM;tracking performance;Energy-saving efficiency
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发布时间：2023-12-11 - 摘要：The considered concretes include ordinary portland cement (OPC)、High Strength Concrete( HSC) and High performance Concrete ( HPC)with the water to binder 0.53、0.35 and 0.27 under three different conditions. This study revealed that the relative dynamic elastic modulus of concrete went through strengthen and deterioration stages subjected to stress corrosion under three conditions, the length of time of these stages are closely related with test environment and concrete type.With the increase of water to binder, the ratio of deterioration was increased, and the length of strength stages was decreased. Immersing drying+30%loading action significantly accelerated the process of stress corrosion damage. Under the action of Immersingdrying +30% load, strengthen section of the length of OPC shorter 67%, compared with the length of time at exposure salt lake. The effect of immersing and drying, HSC Immersingdrying cycles when the stress strength occurred were longer 1.8 times than the OPC and HPC. HSC showed more resistance to stress corrosion in the salt lake regions of china.关键词：immersing-drying cycle;stress corrosion;concrete;relative dynamic elastic modulus
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发布时间：2023-12-11 - 摘要：The existence of solution of second-order nonautonomous equations with (q,p) Laplacian is discussed. Under the new condition, it is well known that second-order nonautonomous equations with (q,p)Laplacian corresponds to functional satisfies PS condition. Some existence theorems of unique solution of second-order nonautonomous equations with (q,p)Laplacian are obtained by using the saddle point theorem.关键词：PS condition;saddle point theorem;second-convex;unique solution
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发布时间：2023-12-11 - 摘要：The growth and development of solid tumors occurs in two distinct phases： the avascular and the vascular phase. During the former growth phase the tumor remains in a diffusionlimited dormant state of a few millimeters in diameter, while during the later phase, invasion and metastasis do take place. A mathematical model of cancer cell breakout and invasion of normal tissue or extracellular matrix is studied. The model consists of a system of four Reactiondiffusiontaxis partial differential equations and a degenerate parabolic partial differential equations. By using the parabolic Lptheory, the parabolic Schauder estimates, principle of comparison and the Banach fixed point theorem, it is proved that this system has a unique global solution.关键词：tumor growth;local solution;global solution
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发布时间：2023-12-11 - 摘要：A boundary control in two-dimensional is proposed for a distributedparameter flexible beam with unknown disturbance and varying tension to minimize the beam vibrations．Flexible beam is a typical infinite-dimensional distributed parameter systems，and its hybrid dynamic model is described in terms of partial differential equations (PDEs) and ordinary differential equations (ODEs)．To avoid control spillover and achieve vibration control in two-dimensional，the PD （Proportional Derivative）boundary controllers in longitudinal and lateral direction are designed respectively based on the original infinitedimensional PDEs model and Lyapunov's direct method to reduce the flexible vibrations．With the proposed PD boundary control，the real-time and robustness of control system are ensured because the proposed controller is simple and independent of system parameters．The uniform boundedness and closed-looped stability can be achieved by Lyapunov's direct method．Simulation results illustrate the effectiveness of the proposed boundary control．关键词：flexible beam;boundary control;Lyapunov‘s direct method;stability
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发布时间：2023-12-11 - 摘要：By use of the backward shift invariant subspace，a necessary and sufficient condition under which a product of a circular analytic signal and a conjugate circular analytic signal is still circular analytic is presented. Particularly, if the Ztransform of the circular analytic signal is holomorphic across the unit circle, the conjugate circular analytic signal is a rational function whose poles are the zeros of the Ztransform of the circular analytic signal. As applications of the above results, the conditions under which two circular analytic signals with length n Fourier series have the same amplitude are discussed.关键词：circular analytic signals;conjugate circular analytic signals;backward shift invariant subspace;amplitude preservation
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发布时间：2023-12-11 - 摘要：A stochasitc models on predator-prey system of two species with ratio-dependence is studied.The property of stochastic ultimate boundedness, the asymptotic moment estimation and the pathwise estimation of the global solution are studied by five techniques, including the theory on stochastic differential equation constructs stochasitc models, the V function, stopping time, some inequalties and It o^ formula.关键词：predatorprey system;stochastic differential equation;It o^ formula;stochastic ultimate boundedness;asymptotic moment estimation;pathwise estimation
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发布时间：2023-12-11 - 摘要：Dendrobium loddigesiiis used in clinical applications widely.In order to further investigate its effective constituent, seven compounds including shihunine (1), 9,10dihydrophenanthrene2,4,7triol (2), moscatin (3), loddigesiinols C (4), moscatilin (5), gigantol (6) and tristin (7) were isolated by silica gel, Sephadex LH-20 and ODS-18 column chromatography from the methanol extract ofDendrobium loddigesiiTheir structures were analyzed by MS and NMR spectroscopy. The compounds 2 and 7 were obtained fromDendrobium loddigesiifor the first time.关键词：Dendrobium loddigesii;isolation;structure identification;effective constituents
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发布时间：2023-12-11 - 摘要：The influence of secondary metabolites on the mix-cultivate marine bacteria and fungus were studied.The result indicated that bacteria obviously affected the secondary metabolites of fungus in the mix-cultivate, and even produce substances that were not found in the fungus or bacteria separately culture by TLC. Eight compounds were obtained from the fermentation broth of coral-derived bacteria L-4 in South China Sea. Their structures were determined to be cyclo (TrpAla)(1),cyclo (GlyTyr)(2), cyclo (AlaTyr) (3), and cyclo (ValTyr)(4), cyclo (GlyPhe)(5)，cyclo (GlyPro)(6), cyclo (AlaVal)(7), and cyclo (GlyAla)(8) by spectroscopic analysis. The compounds1,2,3,4,5,6,7,8were all cyclo-dipeptides and first obtained from the marine coral-derived bacterium of South China Sea, which attributed to further research metabolism of mix-cultivation.关键词：coral derived bacteria;mix-cultivate;secondary metabolites;cyclo-dipeptides;structure identification
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发布时间：2023-12-11 - 摘要：Multi-armed polypropylenimine dendrimer-poly(benzyl-L-glutamate) was synthesized by ring-opening polymerization of BLG-NCA using primary amineterminated polypropylenimine dendrimer (PPI) as the macroinitiator. Its chemical structure was characterized by IR, 1H NMR13C NMR, and GPC analysis. The results showed that the primary amine of PPI participated in initiating the ring-opening polymerization of BLG-NCA monomer. And multiarmed polypropylenimine dendrimer-poly(benzyl-L-glutamate) was successful synthesized. The multi-armed polymer might be a potential candidate as nonviral gene carriers.关键词：polypropylenimine dendrimer;poly(benzyl-L-glutamate);nonviral gene carrier;ring-opening polymerization
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发布时间：2023-12-11 - 摘要：Carbon aerogel spheres were activated by carbon dioxide (CO2) and potassium hydroxide (KOH), respectively. The electrodes of supercapacitor were made from the products before and after activation. To understand the activation mechanism, the pore structure and electrochemical performance of these products were investigated. The results showed that both CO2and KOH activation could improved the pore structure and electrochemical performance, the highest BET surface area of active products could reach 1 320 m2/g and the capacitance were increased by three times, respectively. Furthermore the results also showed that the activation mechanisms of CO2and KOH were different. The mesopores of carbon aerogel spheres were kept after CO2activation. Such mesopores acted as the fast channel of electrons to enhance mass transfer rate. The micropores of carbon aerogel spheres were increased significantly after KOH activation, which enhanced the active surface area to improve the electrochemical performance.关键词：carbon aerogel sphere;activation;electrochemical performance;structure;supercapacitor
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发布时间：2023-12-11 - 摘要：Shenzhen Special Economic Zone (SEZ) was established as a model city in 1979 and it has become a modern industrialization urban during the past three decades. The rapid urbanization has a significant effect on the wetland landscape, and Shenzhen Bay is a typical example. In this paper, the urbanization process in Shenzhen special zone was divided into four stages: early urbanization phase, developed urbanization phase, accelerated urbanization phase and later urbanization phase. The quantitative description characteristic of three main wetland landscape types, including Gei Wei, Mangrove and Intertidal Zone in Shenzhen Bay, were analyzed with grid analysis method, including three different grid scales, 100, 200 and 300 m, by applying the platforms of ARCGIS. The results are as followed:①In the developed urbanization phase, most grids of Gei Wei were transfered with medium strength and focus on the fastest urbanization zone — Futian District, which means Gei Wei suffered heavily humanity destruction and a lot of Gei Wei changed to the humanity landscape such as the builtup area. From 1989, the number of grids which turned out to other landscape types was small with low transfer intensity. ②The transfer area of mangrove was mainly concentrated in the vicinity of the Futian mangrove conservation area, and the transfer strength of which is essential low. From 1989 to 1998, the strength that grid of mangrove turned out to other landscape types was very high. ③The transfer situation of intertidal zone is more complicated. First, its transfer space range was discontinuous. Second, there was a cycle for turn in or out in time. ④The analyses of three different scales for transfer intensity grid were all based on the Jenks natural classification method.The size of grid may cause greater impact in the space distribution of four transfer intensity types.The grid with 200 m scale was the most appropriate scale for the analysis.关键词：urbanization;gei wei;mangrove;intertidal zone;landscape transfer intensity;GRID
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发布时间：2023-12-11 - 摘要：In some Camellia classification literatures, C. longgangensis, C.ptilosperma and C.longruiensis were treated as synonyms of C. flavida,and C.quinqueloculosa ,C. longgangensis var.patens, C.multipetala and C.wumingensis were treated as synonyms of C.flavida var.patens,the taxonomic status of these species was discussed in this paper. The morphological characters of flowers, fruits, seeds and leaves in the 15 populations of these species were studied.According to the similarity of the characters,15 populations were divided into three classification groups. Based on the data of prominent classificational characters including corolla tube height, characteristics of flower color,locular number of ovaries, pericarp thickness,with indumentum of the testa of seeds or not,the correlation between the texture and the thickness of the leaves with the lateral nerves, etc, the morphological variations of samples from three groups were compared and analyzd. The results are as follows: The prominent classificational characters except locular number of ovaries among three groups show significant differentiations. Therefore, these species reduced as synonyms of C. flavida are unreasonable. After examining the type specimens and the original literatures,the authors suggest that C.ptilosperma and C.longruiensis are treated as synonyms of C. longgangensis, and C. longgangensis var.patens and C.multipetala are treated as synonyms of C.quinqueloculosa; both and C. wumingensis should be regarded as three independent species.
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发布时间：2023-12-11 - 摘要：In Arabidopsis thaliana, the red and farred light photoreceptors phytochromes (PHYs) act to involve in regulating flowering. Phytochromobilin synthase (HY2) synthesizes the open chain tetrapyrrole chromophore which is essential to the lightsensing function of phytochromes, and it is a member of the ferredoxindependent bilin reductases (FDBRs). Here, we found a DsTDNA insertion line of Arabidopsis thaliana for the gene encoding the most major ferredoxin (Fd2, At1g60950), which can promote flowering in the process of growth both under longday and shortday conditions. In this report we show that loss of AtFd2 can promote flowering, AtFd2 interacts with AtHY2 in the chloroplast, and Fd2KO mutants are impaired in the responses mediated by phytochromes. Together, these results implicate that loss of AtFd2 may promote flowering by impairing the physiology function of phytochromes.
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发布时间：2023-12-11 - 摘要：The weathering of the rock has a very close relationship with the carbon cycle. The Hanjiang River is the second largest river in Guangdong Province. A hot and humid climate prevails in the Hanjiang River basin. Based on tests and analysis of the samples from the Hanjiang River Basin, it is found that the chemical compositions of waters of the Hanjiang River and its tributaries are dominated by HCO-3SO2-4Ca2+and Na+.Gibbs graph analysis showed that the ion compositions were mainly from chemical weathering of rocks. Correlation analysis and principal composition analysis showed that weathering processes of evaporates, carbonates, and silicate rocks contributed to the total dissolved mass of the Hanjiang River water by 33.4%, 27.7% and 10.5%, respectively, and atmospheric CO2by 202%. The contribution proportion of atmospheric CO2to the HCO-3in the river water is about 50.2%, from which the quantity of CO2consumption is calculated to be 73.33×108mol/a. The descending order of atmospheric CO2consumptions of main tributaries of the Hanjiang River is the Tingjiang River, Shikuhe River, Ningjiang River, Wuhuahe River, Meitanhe River, with 28.08×10813.26×10810.22×1085.17×108 and 2.90×108mol/a, respectively. The total CO2consumption rate is about 252.2×103mol/(km2.a). The descending order of atmospheric CO2consumption rates of main tributaries of the Hanjiang River is the Ningjiang River (718.55×103mol/(km2.a)), Shikuhe River(360.14×103mol/(km2.a)), Wuhuahe River (282.04×103mol/(km2.a)）,Tingjiang River (237.73×103mol/(km2.a)) , and the Meitanhe River (181.18×103mol/(km2.a)). The average chemical weathering rate of the Hanjiang River is 5411 t/(km2.a). The chemical weathering rates of main tributaries are 140.5 t/(km2.a) in the Ningjiang River,71.2 t/(km2.a) in the Shikuhe River, 52.39 t/(km2.a) in the Tingjiang River, 51.02 t/(km2.a) in the Wuhuahe River and 38.04 t/(km2.a) in the Meitanhe River.关键词：hydro chemical characteristics;chemical weathering;atmospheric CO2consumption;Hanjinag River Basin
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发布时间：2023-12-11 - 摘要：Microfaunas of borehole PRD16 in the Pearl River Delta have been quantitatively analyzed in this paper. A total of 24 benthic foraminifera species referred to 12 genera and 13 ostracod species referred to 9 genera were found in the borehole. They can be divided into 3 ecological groups. The microfaunal analytical results, combined with lithological and sedimentary grain characteristics, suggest that the study area experienced environmental changes since the Late Pleistocene. A riverine environment began to develop before 34 600 cal a BP. Between 34 600 and 23 900 cal a BP, the environment generally changed to an estuarine condition. Between 23 900 and 7 960 cal a BP, the sediments experienced weathering and erosion, characterized by a layer of mottled clay. At around 7 960 cal a BP, sea level rose rapidly and an estuary environment with euryhaline foraminifera and brackish ostracod faunas existed until 2 810 cal a BP. Two secondorder sea level fluctuations can be recognized based on the composition and abundance of microfaunas. The maximum water depth occurred at approximately 3 873 cal a BP, demonstrated by the highest abundance of foraminifera and ostracods in the borehole. Since 2 810 cal a BP, the environment gradually changed into a fluvial supratidal zone with increased influence of river processes.关键词：Pearl River Delta;foraminifera;ostracod;Late Quaternary;palaeoenvironment
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发布时间：2023-12-11 - 摘要：Urban spatial growth differentiation of Guangzhou during the transitional period is studied in this paper. The results indicate that urban space can be divided into four parts: urban district, fringe zone, outer space and regional space. The old urban district is subdivided into commercial, residential, and official areas. The fringe zone is mainly in residential and industrial land use with a sprawl growth pattern. The outer space is mainly in industrial and infrastructure land use with a jump growth pattern. The regional space is mainly in infrastructure land use with an extend pattern. The factors affecting urban spatial growth include grovernment, marketing and community forces. Urban spatial growth of Chinese metropolitans is discussed based on the case study of Guangzhou.关键词：urban growth;spatial differentiation;Guangzhou
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发布时间：2023-12-11 - 摘要：Urban spatial growth differentiation of Guangzhou during the transitional period is studied in this paper. The results indicate that urban space can be divided into four parts: urban district, fringe zone, outer space and regional space. The old urban district is subdivided into commercial, residential, and official areas. The fringe zone is mainly in residential and industrial land use with a sprawl growth pattern. The outer space is mainly in industrial and infrastructure land use with a jump growth pattern. The regional space is mainly in infrastructure land use with an extend pattern. The factors affecting urban spatial growth include grovernment, marketing and community forces. Urban spatial growth of Chinese metropolitans is discussed based on the case study of Guangzhou.关键词：urban growth;spatial differentiation;Guangzhou
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发布时间：2023-12-11 - 摘要：Carbon transportation by river system constitutes a key link of the global carbon cycle. Based on monthly sampling and analysis of riverine particulate organic matter for a full hydrological year in the Wuhua River, eastern Guangdong Province,the characteristics and sources of particulate organic matter in the river were discussed and carbon transport fluxes were estimated. The results show that the average contents of particulate organic carbon (POC) and particulate organic nitrogen (PON) in the Wuhua River are 0.77 mg/L and 0.12mg/L, respectively, which are much higher during the flood season than those during the dry season. The relationships between discharge and the TSS, POC, PON contents, and the ratio of C to N reveal that the POM of the Wuhua River is mainly from soil organic matter within the drainage basin, which is decomposed by microorganisms during transportation. POC and PON fluxes exported by the Wuhua River are 430 kg/〖DK〗(km2.a) and 70 kg/〖DK〗(km2.a), respectively. The output fluxes in the flood season account for 74.23% and 76.17% of the total annual output.关键词：riverine particulate organic matter;C/N ratio;soil erosion;the Wuhua River
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发布时间：2023-12-11
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