最新刊期
卷 48 ， 期 6 ， 2009
- 摘要：Key words:multivalued stochastic differential equation,coupling,coupling operator,coupling time,martingale approach,Harnack inequality,strong Feller关键词：multivalued stochastic differential equation;coupling;coupling operator;coupling time;martingale approach;Harnack inequality;strong Feller
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发布时间：2023-12-11 - 关键词：curve shortening flow;triple junction;Young's law
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发布时间：2023-12-11 - 摘要：In order to distinguish the target class from outliers accurately, One-Class Classifier (OCC) should take into account the prior knowledge of the target class. However, One-Class SVM (OCSVM), the stateoftheart OCC, neglects the data's distribution information while finding the optimal hyperplane. Structured OCSVM(SOCSVM), the novel proposed OCC, alleviates this problem by embedding the withinclass scattered matrix of the target data into OCSVM. As a result, SOCSVM not only overcomes the above disadvantage of the OCSVM, but also provides a unified framework for the present SVM algorithms how to consider intrinsic structure of the data. Moreover, to improve the efficiency of SOCSVM, linear programming algorithm called SlpOCSVM is proposed to instead of the quadratic programming solving for SOCSVM. Through minimizing the functional distance of the data's mean to the hyperplane, the optimal hyperplane is attracted automatically to the place of the minimum positive half space without borrowing the origin as a representative of the outlier anymore . The experiment results on toy problem and real data sets demonstrate the advantage of SOCSVM and its linear programming algorithm.关键词：one-class classifier;support vector machine;structured information;quadratic programming;linear programming
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发布时间：2023-12-11 - 摘要：Combining the approximate gradientbased steepest descent algorithm and the pattern search algorithm, the GP algorithm, a new local optimization algorithm for conceptual hydrologic model parameters is presented. With Nash facticity coefficient as the target function the random search techniques is used for searching parameter space, then optimize the selected parameter set using GP algorithm. The global optimization parameter is achieved by filtering parameter space strategy. The abovementioned method comprise the derivative information and stochastic properties, make the optimization set escaping the local maximum to the global set. The practical efficiency is verified by using a case in YandLou unite drainage basin. It is shown that parameters of hydrologic model can be automatically calibrated successfully关键词：GP algorithm;stochastic optimization;parameters calibration;Xinyanjiang model
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发布时间：2023-12-11 - 摘要：By employing Krasnoselskiis fixed pomt theorem,the existence of nonoscillatory solutions of the secondorder nonlinear neutral dynamic equations on time scalesis established.The obtained results cover those for secondorder nonlinear neutral differential equations and provide new crtteria for secondorder nonlinear neutral differential equations.关键词：second-order nonlinear dynamic equations on time scales;nonoscillatory solutions;existence;neutral;Krasnoselskii's fixed point theorem
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发布时间：2023-12-11 - 摘要：The use of mass spectrometry as a proteomics tool is poised to revolutionize early disease diagnosis and treat. Unfortunately, due to existing “the curse of dimensionality”, most standard machine learning techniques cannot be directly applied to recognition proteomic mass spectrometry,and these methods also faced with the problem of poor recognition performance. For better efficiency to use principal component analysis (PCA) and local linear discriminant embedding (LLDE) for face recognition, a Double-Time Projections method and a Modified Double-Time Projections method are proposed for recognition proteomic mass spectrometry. The proposed methods first do denoising and dimension reduction by T-test, and then obtain first projection feature vectors with minimum mean square error and get second projection feature vectors with maximum separability. Finally, preprocessed data are projected in the sub space based on two feature vectors and, are classified. The experimental result from the dataset of ovarian cancer proteomic mass spectrometry indicates that the proposed methods have a better accuracy than available methods.关键词：proteomic mass spectrometry;principal component analysis;locally linear embedding;maximum margin criterion;pattern recognition
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发布时间：2023-12-11 - 关键词：quantum dots;magic angular momentum;electronic structures;symmetry constraints
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发布时间：2023-12-11 - 摘要：Investigation of optical pumping for binary mixtures may provide information on the interaction between atomic systems and open up possibility to control response time.Considered Rb isotope85Rb and87Rb as binary mixtures, optical pumping response can be observed with using square modulated field at 10Hz and two channels of RF sources for NMR of85Rb and87Rb respectively.Based on proposed model of three energy levels, unitary system or binary mixtures of85Rb and87Rb can be accurately described with an exponential function.According to the relation of response time between binary and unitary, the response time for mixtures is contributed from unitary ones and their concentrations.关键词：optical pumping;nuclear magnetic resonance;binary mixtures;responsibility
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发布时间：2023-12-11 - 摘要：By employing the three-dimensional finite element method, the working mechanism of whiteandblack pavement treated by impact compaction was studied, and then the influence of the overlays' thickness on the mechanical properties of the new asphalt concrete layer (AC) was explored. The simulation results show that a gap will appear between the overlay and the broken existed concrete slab under the wheel load, which is the special working mechanism of the recovered pavement. Under traffic load the potential cracks will rise transversely at the bottom of AC, while the asphalt surface is undestroyed although it is directly suffered from the wheel load. The maximal stress in AC decreases linearly with the increase of the overlays thickness, either AC or the cement treated base (CTB). The pavement cracks would be efficiently decreased with the increase of the overlays' thickness, especially with the increase of CTB's thickness. However, the effect is not evident in improving the rutting resistance of AC by increasing the thickness of the overlays.关键词：overlay;pavement;impact compaction;mechanical properties;finite element method
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发布时间：2023-12-11 - 摘要：The gradation impact on mineral granular masses segregation was studied for less segregation materials in pavement. The segregation test was built for pavement material detection, and mineral granular materials of different gradation index was designed by gradation theory. According to segregation test, the relation between gradation and segregation of granular masses was analyzed with gradation index, average diameter and diameter distribution index as the representation parameters of gradation. For granular masses with the same maximum diameter particle, the study shows that average diameter and diameter distribution index both having critical value, the critical value gradation has the minimize segregation and other gradations have more serious segregation. Critical value gradation is the gradation that remains reasonable voids when the next smaller particles fill the voids left by the bigger particles. It also found that average diameter and diameter distribution index have a good correspondence and the latter reduces with the former increasing. Finally, the results of mineral granular material segregation test and asphalt mixture segregation in pavement was analyzed.关键词：highway engineering;granular masses;continuous distribution model;segregation;diameter distribution index;gradation
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发布时间：2023-12-11 - 摘要：Damage effective functions reflect the affections related the damage variables to the elastic constants independent of each other of the materials, and its detailed expressions were defined by the geometric features and could be derived from the micro-mechanical damage theories. Firstly, the relationship between the porosity rate and damage variables of the porous materials were given, and then the double scalar damage variables expressions of the isotropic elastic damage were derived. Then, the different influence to damage effective functions by the porosity rate and damage variable in porous media materials was discussed and some valuable conclusions were derived from the point of the relationship between the porosity rate and damage variable. It is shown that the conclusions are beneficial to the further research on the damage mechanics theory.关键词：isotropic elastic damage;damage effective functions;porous media;porosity rate
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发布时间：2023-12-11 - 摘要：Distyrylarylene derivative is one of the most promising blue OLED materials with good film forming ability and high thermal stability. Two compounds were synthesized by introducing the conjugated groups to the distyrylarylene backbone by using WittigHorner reactions. Their chemical structures were characterized by 1H NMR,IR,MS and EA analyses, and the properties were investigated by UV,PL,TGA,DSC,PLM and XRD analyses. The results showed that (1) two compounds emitted strong fluorescence, and the emitting strength of the compound with phenothiazine structure was stronger than that with carbazole structure; (2) the compounds possessed high thermal stability; (3) the compounds had good solubility in organic solvents and film forming ability, which was advantaged for OLED device fabrication using spincoating method; (4) the compound containing phenothiazine groups exhibited a Smectic A liquid crystalline phase under hot-stage PLM.关键词：organic electroluminescent materials;distyrylarylene;synthesis;characterization;liquid crystalline property
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发布时间：2023-12-11 - 摘要：A new chromone derivative named as 5-dihydroxy-2-methyl-6-(3-methylbut-2- enyl)-4H-chromen-4-one (1), a novel cyclic tetrapeptide(2)and three cyclic dipeptides were isolated from the mangrove endophytic fungus ZZF41 from the South China Sea. Their structures were characterized by MS, NMR. Compound 1 exhibited weak cytotoxicity towards KB and KBv200 withIC50values of more 50 μg/mL. Compound 2 showed cytotoxicity towards KB and KBv200 with IC50values of less 3.56 μg/mL, respectively.关键词：endophytic fungus;chromone derivative;cyclic peptide;metabolites
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发布时间：2023-12-11 - 摘要：1-butyl-3-methylimidazolium hydrosulfate(［BMIM］HSO4) was synthesized with N-methylimidazolium and characterized. Some physical chemistry properties concerned, such as density, surface tension, viscosity, and electrical conductivity, are investigated and solvent performance is also studied. It is discovered from the experiments that this kind of ionic liquid has comparative electrical conductivity with familiar ionic liquids and the electrical conductivity follows the Arrhenius equation. Density, surface tension as well as viscosity of the ionic liquid decrease with increase of temperature. In addition, the ionic liquid is soluble in most conventional solvents and metal oxides have some solubility in it, which lays the foundation of direct electrolysis of metal oxides in ionic liquids.关键词：room temperature ionic liquid;1-butyl-3-methylimidazolium hydrosulfate;physical chemistry properties;solubility
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发布时间：2023-12-11 - 摘要：The interaction between potassium sorbate (PSA) and bovine serum albumin (BSA) was investigated by fluorescence spectroscopy, resonance lightscattering (RLS) spectroscopy. The quenching mechanism was analyzed referring to PSA against the fluorescence and the resonance light scattering spectra of BSA. The apparent binding constants (KA) between PSA and BSA were 223×103 L· mol-1 (288 K), and 274×103 L· mol-1 (293 K), respectively. The corresponding binding sites values (n) were 102 and 099. The changes of negative entropy change and enthalpy indicate that the interaction of PSA and BSA was driven mainly by electrostatic interactions. The binding process was a spontaneous process in which Gibbs free energy change was negative. The effect of PSA on the conformation of BSA was analyzed by synchronous fluorescence spectroscopy. Furthermore, the binding distance r=2.83 nm between PSA and BSA was obtained based on the mechanism of Forster non-radiation energy transfer.关键词：potassium sorbate;bovine serum albumin;interaction;fluorescence spectra;resonance light scattering spectra
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发布时间：2023-12-11 - 摘要：A mixed culture of two epiphytic fungi from a rotten fruit of mangrove Avicennia marina produced two antibacterial secondary metabolites (A and B). Their structures were elucidated as neoaspergillic acid (A) and kojic acid (B) by comprehensive spectral methods (mainly by 2D NMR spectral methods). The structure of compound B was further characterized by single crystal X-Ray diffraction analysis. The crystal of compound B belongs to monoclinic system, space group is P 21/n. The unit cell parameters are: a=0.378 33 (3) nm,b=1.837 58 (14) nm, c =0.848 89 (7) nm, α=90°, β=96.752 0 (10)°, γ=90°, V=0.586 06 (8) nm 3 and Z=4. Compound A was not obtained when either strains was cultured individually. The results showed that the application of mixed culture technique would be contribute to discover more novel natural products from marine microorganisms.关键词：Avicennia marina;epiphytic fungus;mixed culture;metabolite;crystal structure
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发布时间：2023-12-11 - 摘要：The endo-β-glucanase III gene (eg3 was obtained from the total RNA of Trichoderma viride AS3.3711 by RTPCR. Sequence analysis indicated that this eg3 gene was composed of 1 257 nucleotides, coding for 418 amino acid residues, and had its own signal peptide. The sequence homologies between this gene with Trichoderma Reesei eg3 were 99.6%. Then it was cloned into the high-copy integrative expression vector pScIKP, generating a recombinant plasmid named pScIKP-eg3, which was then transformed by electroporation into Saccharomyces cerevisiae AS2.489 after linearization. Transformants were detected by SDS-PAGE analysis, Congo Red method and enzyme activity assay. The results showed that transformants could secrete recombinant EG III and produced hydrolysis halos on the Congo-Red-CMC plate, indicating that this eg3 gene was correctly expressed in S. cerevisiae.The highest enzyme activity of recombinant EG III reached 120 U/mL after 60 h cultivation, and the optimum temperature and pH were 60 ℃ and 6.0 respectively. The genetic stability of transformants achieved 99.17% after 50 generations in nonselective medium. In conclusion, the eg3 gene of T. viride could be expressed in industrial yeast strain stably and efficiently.关键词：endo-β-glucanase III;Saccharomyces cerevisiae;Trichoderma viride;integrative expression
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发布时间：2023-12-11 - 关键词：Paralichthys olivaceus;fibrinogen β;cloning;expression
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发布时间：2023-12-11 - 摘要：A variety of factors affect edge influence, edge influence depths vary in different time and space scales.At present,only small amount of qualitative researches on edge influence depth's affecting factors were reported, furthermore quantitative analysis researches lack, thus more researches, especially quantitative researches, are needed. This paper analyzed affecting factors of biomass edge influence depth using data of the upper reaches of Min River forest and farmland boundaries. Using GIS software, we overlap boundary type map, digital elevation map, land-use map and rainfall data map to get elevations, slopes, aspects and precipitations of the edges and patch areas on both sides of the edges, which are further processed with DEI using multiple linear regression analysis method in SPSS. The results show that edge influence depth between forest and farmland is affected by elevation and slope evidently and there is negative correlation between them. When elevation and slope of the boundary is less, the DEI is broader. Aspect impacts DEI less obviously, while precipitation and patch area have no evident impacts on DEI.关键词：Min River;depth of edge influence;affecting factor;multivariate linear regression
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发布时间：2023-12-11 - 摘要：To observe anatomy of the Hucho tai men digestive system,describe the morphological characteristics of the teeth, tongue and gill rakers which were related with feeding; measurement of body length, head length, snout length , aperture of mouth breadth, mouth length. The shape of Hucho tai men stomach, pyloric caeca, liver, pancreas, gallbladder were described;the lengths of esophagus, stomach, intestine and digestive tract were measured;and the relevant ratioes were calculated. The results showed that:The Hucho tai men digestive tract had typical characteristics of the carnivorous fish digestive tract , aperture of mouth was big, cavum oropharyngeum length / head length was 062,intestine was shorter, intestinal length / body length was 069, a clear mucous membrane folds were shaped in the inner process of esophagus 、stomach and intestinal walls. Its liver did not divide into mala and the pancreas existed by the form of line.Meanwhile, the section of the digestive tract 、the feeding habits and morphosis of the digestive system were discussed.
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发布时间：2023-12-11 - 摘要：κ-Carrageenan oligosaccharides were prepared by the method of enzymatic hydrolysis using κ-carrageenase from Pseudoalteromonas sp. AJ5-13. With the analysis of composition and structure by using ESI-TOF-MS and13关键词：κ-carrageenan oligosaccharides;enzymatic hydrolysis;HSV-1;antiviral activity
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发布时间：2023-12-11 - 摘要：In order to research the effects of anthraquinones extracte from Rheum officinale Baill on prevention of high temperature of Macrobrachium rosenbergii, Macrobrachium rosenbergii were divided into five groups randomly. The controls were fed with basal diet, the treated groups were fed with basal diet supplemented with 0.05%, 0.10%, 0.200%, 0.40% anthraquinones extracte for 8 weeks, respectively. After that, shrimp were stressed by high temperature at 35 ℃ for 48 hours continuously. Then the growth and the changes of nitrogen oxide, lysozyme, glucose, triglyceride and cholesterol and in haemolymph before and after the stress were investigated. The results showed that 0.10% dose group significantly increased weight gains and reduced feed conversion rate, and 0.40% dose group significantly increased haemolymph lysozymes contents before the stress. After the stress, 0.10% and 0.20% dose groups were relatively higher in haemolymph lysozymes and nitrogen oxides contents than those of the control. Stress also caused mortality in all groups of which 0.10%~0.20% dose groups were less than 30%, but the control was about 60%. It is concluded that ingestion of 0.10%~0.20% dose of anthraquinones extracte could help prevent negative effects of stress and improve shrimp growth.关键词：Macrobrachium rosenbergii;anthraquinones extracte from Rheum officinale Baill;immune ability;high temperature stress;growth
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发布时间：2023-12-11 - 摘要：The data collected from the Pearl River Delta were used to study the impact of urban planning on local meteorology. The results show that urban heat island became stronger and the influenced area was larger compared with preurban situation. Wind speed decreased and light wind speed area increased. The influence of Guangzhou urban planning was assessed based on atmospheric environmental assessment indices. The apparent influencing indices are urban heat island intense, distribution of light wind speed and atmospheric selfclear capability. With urban expansion, urban heat island became stronger, wind speed decreased and atmospheric selfclear capability decreased. The integrated analysis shows that urban expansion has obvious influence on atmospheric environment.关键词：urban scale planning;atmospheric environment effect;the Pearl River Delta
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发布时间：2023-12-11 - 关键词：Pb isotope;petrogenesis;volcanic rocks;late Mesozoic;the southern Da Hinggan Mountain
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发布时间：2023-12-11 - 摘要：Incorporating physical characteristics of processes in hydrological analysis is one of the focuses of hydrological field. A scale model is introduced and its merits and limitations in calculating design rainfall depths, compared to traditional frequency analysis (direct method), are analyzed in this paper. The data were collected from rainfall gauges of Hong Kong New Territory. It is found that the scale model is applicable for rainfall durations of 120, 360, 720 and 1 440 min. The calculated rainfall depths are smaller than those from the direct method. The differences between rainfall depths increase with return periods. It is concluded that the scale model is more reasonable than traditional frequency analysis and can be used as an alternative or complement to design rainfall depth calculation.关键词：direct method;scale model;design rainfall depths
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发布时间：2023-12-11 - 摘要：Isotopic variations of soil water and rainfall are studied through rainfall infiltration experiments under isotopically depleted rainfall inputs condition. The isotopic compositions of rainfall and soil water mix in the process of rainfall infiltration, and the isotopic compositions of outflow decrease with time and then keep constant. The slope of hydrogen and oxygen isotopes of outflow is determined by that of mixing line connecting the isotopic compositions of rainfall and the initial soil water. Using curve fitting method to fit isotopic variations of outflow, it is found that the transfer function distribution of isotopic composition of outflow is exponentialpiston flow model distribution, and the transfer function of hydrogen isotope is similar to that of oxygen isotope.关键词：hydrogen and oxygen stable isotopes;rainfall infiltration;mixing;transfer function
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发布时间：2023-12-11 -
Effect of Water Content on Strength and DeformationCharacteristics of Reinforced Expansive Soils
摘要：Expansive soil samples reinforced with a biaxial geogrid are adopted to carry out a series of unconfined compression, consolidated and undrain tests at different water content. Effects of water content on the strength and deformation characteristics of reinforced expansive soils are studied. Water content has significant effect on the failure model of reinforced expansive soils; With increasing water content, the effect of reinforce on the stressstrain curves decreases, and the change of peak strength and residual strength decrease. Water content has little effect on the failure mode, in which all the stress-strain curves show strain-hardening; With increasing water content, both the peak strength, and increment after reinforcement decrease sharply. The effect of water content on the initial yield stress is related to the layers of reinforce.关键词：biaxial geogrid;reinforced expansive soils;water content;strength and deformation characteristics;failure model;South to North Water Transfer Project (SNWT)- 1377
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发布时间：2023-12-11 - 摘要：To ensure the carrying safety and longterm durability of nuclear waste, the tests of flexural properties were carried out respectively at normal temperature and after being heated to 150℃ using orthogonal mix proportion design and incorporating steel, polypropylene hybrid fiber, fly ash or steel fiber solely in the concrete. Based on gradation and variance analyses, different kinds of admixtures and their effects on toughness of concrete are quantified. Fiber type and incorporation can improve the mechanical properties of high performance concrete effectively after cracking, which is more remarkable after being heated. Steel fiber A with sheared threads has the best effect on anticracking and toughening at preand post heating. With the increase of fiber incorporations, the flexibility of hybrid steel fiber concrete increases basically. The hybrid steel fiber is better than steel fiber with single incorporation in flexural properties at normal temperature, but no difference after being heated.关键词：hybrid fiber concrete;flexural property;steel fiber;polypropylene fiber;fly ash
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发布时间：2023-12-11 - 摘要：This paper firstly analyses the performances of several RFID anti-collision algorithms under the environment of dense tags. The performances discussed include total time consumed, system efficiency, total bits transmitted by the reader and average bits sent by each tag and so on. Then a novel improved algorithm based on ALOHA algorithms is present. The new algorithm has high system efficiency around 0.41 and less amount of data transmitted which is decreased by 50 percent at least compared with treebased algorithms. Lastly, conclusions are made and directions of further work are given.关键词：RFID;tag anticollision;framed slotted ALOHA;binary tree;query tree
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发布时间：2023-12-11
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