最新刊期
卷 53 ， 期 2 ， 2014
- 摘要：As low field1H NMR relaxation can effectively measure moisture and fat in oil seed, the key problem is technology for identification of the contribution from these components respectively. The peanut mass change with hydrogenation is recorded for optimizing NMR measurement process. The CPMG(Carr-Purcell-Meiboom-Gill）technique was applied to obtain the NMR transverse relaxation of peanut and peanut oil samples, and the resonance relaxation spectrum was analyzed with the method of continuous spectrum iteration. According to the variation of relaxation spectrum peak area with peanut mass, the assignments of the relaxation peaks were determined with the results from peanut oil. The study found that the transverse relaxation spectrum peaks reflected the fat content in dry peanut. Compared with fat content measured with traditional technology, the peak areas for dry fresh peanut had a positive linear correlation with its fat concentration. The results demonstrate that the NMR transverse relaxation spectrum can be used for determination of fat content in fresh peanut.关键词：nuclear magnetic resonance;transverse relaxation spectrum;fat;peanut
- 1039
- |
- 323
- |
- 0
发布时间：2023-12-11 - 摘要：Based on the cusp catastrophe theory, the lateral buckling of parallel dual-arch-ribs was studied. The displacement function, as well as the energy representation were constructed when there was a lateral buckling in the dual arch-ribs. By mathematical transform，the energy cusp catastrophe model was established, then the system's equilibrium surface M equation and bifurcation point set B equation were obtained. Through the analysis of buckling conditions of dual-arch-ribs system, bifurcation point was calculated, and the formula of lateral buckling critical load was derived，furthermore, a new calculation method of lateral buckling critical load of parallel dual-arch-ribs was proposed. At last, comparing theoretical results based on the cusp catastrophe theory with those obtained from FEM, it is verified that the calculation method presented is sufficiently accurate. The study has opened up a new way for the lateral buckling of the arch structures.关键词：parallel dual-arch-ribs;cusp catastrophe theory;lateral buckling;critical load;new calculation method
- 479
- |
- 350
- |
- 0
发布时间：2023-12-11 - 摘要：A method for traffic impact analysis with pre-trip traffic information is presented, in which travellers'reactions to the traffic information are described by stochastic route choice models. Travellers are divided into two groups according to the information provision: the travellers who receive information will avoid the congested region when they making decisions, otherwise they follow the logit style stochastic route choice behavior. Traffic assignment algorithm for such mixed behaviours is proposed.The central business district, the Pearl River New Town in Guangzhou, China, is chosen to evaluate the impacts of traffic information.It is found that the inappropriate information has negative impact on road network, and more information does not guarantee improvements of the network. A discussion on the optimization of traffic information providing is presented.
- 619
- |
- 315
- |
- 0
发布时间：2023-12-11 - 摘要：A design scheme of multi-target real-time tracking system is presented and factors affecting tracking performance are analyzed.A kind of Extended Kalman Filter(EKF) algorithm based on single observation and self-adaptive node scheduling scheme based on the function of the EKF algorithm is proposed. In addition, many mechanisms and strategies are introduced as auxiliary for trajectory tracking. The experimental result validates the good performance of the tracking algorithm and node scheduling strategy. It has advantages of reducing calculation and energy consumption, shortening measurement period and improving tracking precision.关键词：wireless sensor network;target tracking;self-adaptive node scheduling;EKF
- 564
- |
- 364
- |
- 0
发布时间：2023-12-11 - 摘要：The kernel technology of Compressed sensing theory is to find the sparsest representation to recover original signal data, in which the convex optimization algorithm of minimization the l1norm is a important method. At present, a key algorithm solved minimization the lp(p≤1)norm is iterative reweighted least squares algorithm（IRLS－p0关键词：iterative reweighted;matrix rank;compressed sensing;Frobenius norm
- 685
- |
- 374
- |
- 0
发布时间：2023-12-11 - 摘要：Laser irradiation induced phase change of a new amorphous N:GeSb film is studied by coherent phonon spectroscopy, which is very sensitive to its microstructure. It is found that a new coherent optical phonon(COP) occurs as laser irradiation fluence reaches some threshold, implying laser-induced phase change emerged. Meanwhile, this new phonon also occurs in annealed crystallized N:GeSb film, which proves that the laser irradiation does lead to the crystallization of the N:GeSb film. Pump fluence dependence of COP dynamics of laser-induced crystallized N:GeSb film shows that the frequency and life time of COP decrease as pump energy density increases, which is in accordance with the annealed crystallized N:GeSb film. So it implies the high crystalline quality of the laser-induced phase-change film and the potential application of N:GeSb films in optical phase change memory.关键词：ultrafast spectroscopy;laser-induced phase change;coherent phonon;N:GeSb film;pump-probe
- 710
- |
- 336
- |
- 0
发布时间：2023-12-11 - 摘要：The method of cross-compiler building step by step has high complexity and low rate of success. To address the problem, a simplified and robust method is proposed. The method utilizes a full-featured cross-compiler to compiler Glibc instead of the static GCC, which reduces the build process steps, the number of parameters and complexity of the entire process, and improves the rate of success. The results show that the method can effectively reduce the complexity of the method to build a cross-compiler step by step and improve the rate of success of the method. In order to enhance the universality of the method, the parameter setting, version selection, dependencies of library files and other issues are analyzed and summarized also on the method proposed.关键词：ARM;LINUX;cross-compiler;embedded;step by step
- 469
- |
- 386
- |
- 0
发布时间：2023-12-11 - 摘要：Semi-fragile watermark has wider applicability, as it can distinguish malicious tampering and normal mesh processing. Most present algorithms can only tolerate a few types of normal mesh processing. A novel semi-fragile watermarking algorithm based on mesh content is proposed. In this algorithm, mesh is partitioned into some sub-meshes, and semi-fragile watermarks are hidden in DCT coefficients of each sub-mesh. When mesh is tampered, the position occurred can be located by matching the extracted watermark sequence and original watermark sequence. Experimental results show that the proposed algorithm can tolerate various mesh normal processing, such as mesh RST similar transforming, and quantization of vertex coordinates with low intensity, while is sensitive to malicious tampering. The proposed algorithm can also locate the tamering positions with relatively high precision.关键词：3D watermark;mesh watermark;semi-fragile watermark;DCT;content authentication
- 605
- |
- 282
- |
- 0
发布时间：2023-12-11 - 摘要：Based on the Banach fixed point theorem and properties of differential and integral calculus of fractionalorder, the existence and uniqueness of solutions for the fractional-order generalized Logistic equation with delay are discussed. Some sufficient conditions for uniform stability of solutions are obtained. The numerical solution is obtained by the modified Adams-Bashforth-Moulton predictor-corrector scheme.关键词：fractional-order derivative of Caputo;fractional-order logistic equation with delay;Banach's fixed point theorem;existence and uniqueness
- 641
- |
- 323
- |
- 0
发布时间：2023-12-11 - 摘要：The existence of the global-in-time entropy weak solutions is obtained for the Cauchy problem of the weakly dissipative Degasperis-Procesi equation with the initial value in L2(R) ∩ L4(R).关键词：the weak dissipative Degasperis-Procesi equation;well-posedness;blow-up scenario;strong solution;global weak solution
- 560
- |
- 319
- |
- 0
发布时间：2023-12-11 - 摘要：Some pointwise properties of Orlicz function spaces which are generated by a N－function and equipped with the generalized Orlicz norm are studied. By using geometrical theories and techniques of Banach spaces, criteria of UR points and WUR points in these spaces are presented. Sufficient and necessary conditions are obtained to make the Orlicz function spaces be locally uniform rotund and weakly locally uniform rotund .关键词：UR point;WUR point;generalized Orlicz norm;Orlicz function space
- 461
- |
- 278
- |
- 0
发布时间：2023-12-11 - 摘要：This study explore the possibility of structural breaks in daily realized volatility series of agricultural commodity futures, and conduct an out-of-sample forecast to explore the effects of structural break on the performance of ARFIMAX-FIGARCH models for the realized volatility forecast, concentrating on procedures that utilize a variety of estimation window sizes designed to accommodate the potential structural breaks. The results indicate that the realized volatility of agricultural commodity futures exhibits the properties of structural breaks, asymmetry, and double long memory. In addition, combination forecasts with time varying weights across individual forecast models estimated with different estimation windows performs well, and the nonlinear combination forecasts with weights chosen based on a nonparametric kernel regression and the linear combination forecasts with weights chosen based on non-negative restricted least squares and Schwarz Information Criterion appears to be the most effective methods for forecasting the realized volatility of agricultural commodity futures under structural breaks.关键词：agricultural commodity futures;realized volatility;forecast;structural breaks
- 526
- |
- 345
- |
- 0
发布时间：2023-12-11 - 摘要：In order to investigate the influence of β-phase on the mechanical properties of CaCO3/polypropylene (CaCO3/PP) composites, β-PP composites were prepared by PP filled with the mixture of nano CaCO3(CC) supported with β-nucleating agent (β-CC) and CC or micro CaCO3(WC). Using PP-g-MA, POE-g-MA and EVA-g-MA as compatibilizers, the compatibilized composites were also prepared. The results indicated that the tensile strength of PP composites decreased and tensile modulus increased with increasing the content of CaCO3. Addition of β-CC increased tensile modulus of PP and had no influence on the tensile strength of PP. Compatibilization of PP-g-MA increased the tensile strength, tensile modulus and impact strength of filled PP composites. Compatibilization of POE-g-MA significantly increased the impact strength of filled PP composites. Compatibilization of EVA-g-MA decreased the tensile properties of filled PP composites. The impact strength of β-CC/PP composites increased with increasing the content of β-CC and the impact strength of β-CC/CC/PP and β-CC/WC/PP were higher than those of CC/PP(w(CC)/w(PP)=5/95) and WC/PP(w(WC)/w(PP)=5/95),due to the formation of βphase.关键词：isotactic polypropylene;CaCO3;β-nucleation;mechanical properties
- 565
- |
- 303
- |
- 0
发布时间：2023-12-11 - 摘要：Two mangrove endophytic fungi K38 and E33 from the South China Sea Coast were chosen to co-cluture. Ten secondary metabolites, cyclo(L-phe-L-pro)（1），cyclo(L-phe-L-pro) (1), cyclo(D-pro-L-phe) (2) , cyclo (L-phe-trans-4-hydroxy-L-pro) (3)，cyclo(cis-4-hydroxy-D-pro-L-phe) (4)，cyclo(L-pro-L-tyr)（5）, cyclo(D-pro-L-tyr)（6）, cyclo(D-pro-D-trp)（7）, xylitol（8）, adenosine（9）and uridine（10）were isolated from the nbutyl alcohol extracts. Among them, Compound 6 was obtained from fungi for the first time, and compound 2, 6, 7, 8 were isolated from marine fungi for the first time.关键词：mangrove endophytic fungi;co-culture;dipeptide
- 577
- |
- 301
- |
- 0
发布时间：2023-12-11 - 摘要：Static tests were carried out to study the effect of ozonic disintegration characteristics on waste activated sludge in laboratory. The results showed that ozone improved the effect of sodium hydroxide with increasing oxidizing time at different levels. A substantial increasement in the concentration of protein and UV254 were observed. The concentration of protein increased to 56.3 mg/L and had a largest increase of 40.81% with 30minute ozonation. Meanwhile, UV254 was 46.21% more than the raw samples.The pH value reduced gradually with the increase of the ozone dose. The microscopic analysis and the particle size assay also showed that ozone favored the destruction of the activated sludge flocculate structures, reduced and disrupted the crystal size.关键词：ozone;excess sludge;oxidation;pH;protein;UV254;particle size
- 552
- |
- 308
- |
- 0
发布时间：2023-12-11 - 摘要：β-Ionone was pyrolyzed under helium atmospheres at 300, 400, 500, 600, 700 and 800 ℃ respectively, and the pyrolysates were analyzed by online gas chromatography /mass spectrometry (GC/MS). The results showed that (1) Forty-eight substances were detected from the pyrolysates at 800 ℃; (2) At 600 ℃ only 10.765% of β-ionone was pyrolyzed. The pyrolysis reaction became more intensive at 700 and 800 ℃, 18.149% and 21.286% of β-ionone was pyrolyzed; (3) the percentage of aromatic compounds increased with the increase of pyrolysis temperature. The possible pyrolysis mechanism of β-ionone was preliminarily investigated based on the major pyrolysates.
- 527
- |
- 336
- |
- 0
发布时间：2023-12-11 - 摘要：7-Amino-4-methyl-2(1H)-quinolinone was synthesized by the reaction of m-phenylenediamine with ethyl acetoacetate (3), which was further reacted with nitrilotriacetic acid and produced a new amide compound 5. The chemical structure of compound 5 was characterized by IR, 1HNMR, and MS analyses. Coordination of compound 5 with La(NO3)3produced a new La complex 6 with a molecular formula of ［La(C16H15N3O6)NO3］·4H2O, which was analyzed by IR, MS, TG-DTA, elemental analysis, and molar conductivity. The result of fluorescence analysis showed that the Lacomplex had a stronger fluorescence and narrower frequency-domain. The interaction of compound 5 with herring DNA solution was also studied by fluorescent spectroscopy at different concentrations. An obvious change of the fluorescent spectroscopy was observed, showing that there is a strong interaction between the DNA and compound 5. Addition of herring DNA could effectively enhance the luminescence intensity, and an intensity increased to 40% was observed at a DNA concentration of 4.02×10-6mol/L. Therefore, compound 5 has potential applications in DNA analysis and/or prevention and treatment of diseases.关键词：fluorescent compound;La complex;biological detection;synthesis
- 555
- |
- 329
- |
- 0
发布时间：2023-12-11 - 摘要：Chemotaxonomic study of 25 taxa(24 species and 1 variety) of Eurya, in a total of 28 samples were carried with high performance liquid chromatograms method. Twenty-three chemical components from the whole samples were recognized according to the relative retention time of the chromatograms. The results showed that the chromatograms stabilized between same species and varied among different species, which could be used to distinguish species from each other. In order to reveal the inter-specific relationships and the taxonomic positions of these species, chromatograms data were submitted to cluster analysis using UPGMA and NJ methods and then the taxonomic significance of chemical component in genus Eurya were discussed based on the two dendrograms. Our study showed that the HPLC chromatograms method was rapid, intuitive and repeatable, and it could be mentioned as a good marker to classify the plants of Eurya. In addition, this study also provided useful data for studying the resource utilization in the genus.关键词：Eurya;HPLC chromatogram;chemotaxonomy;cluster analysis;taxonomic significance
- 518
- |
- 276
- |
- 0
发布时间：2023-12-11 - 摘要：The present study was designed to reveal the composition principles of four herbs in compound xueshuantong capsule (CXC) based on grey relational analysis approach. According to uniform design, CXC samples with different proportions of the four herbs were prepared on the premise of the original formula proportion. Efficacy experiments on animals were conducted to evaluate the CXC samples effects of promoting blood circulation and removing blood stasis. Grey relational analysis approach was used to analyze the relevance between CXC samples and efficacy. The results demonstrated that Panax notoginseng was the key herb performing an obviously higher efficacy contribution in CXC. It could significantly regulate blood clotting activity, improve microcirculation and alleviate the blocking in the capillaries and small veins. Meanwhile, Radix astragali, Salvia miltiorrhizae and Radix scrophulariaceae could significantly reduce the aggregation between red blood cells, resulting in smooth blood flow and prevention of blood hypercoagulable state. Therefore, four herbs together could influence different aspects of blood system, which fully embodies the multi-component and multi-target peculiarities of CXC.关键词：Compound Xueshuantong Capsule;efficacy;grey relational analysis;composition principles
- 627
- |
- 381
- |
- 0
发布时间：2023-12-11 - 摘要：BALB/c mice were immunized with G1b-1 protein, the main allergen from wheat. The splenocytes of the immunized mice were fused with NS-1 myeloma cells. Cell fusion and limited dilution assay were used to screen hybridoma with stable secretion character and mice ascites were induced by the selected bybridoma. Monoclonal antibodies(McABs) were purified using affinity chromatography and further tested by their specificity，subtype，titers and crossreactivity. The antigen epitope specificity of the McABs was examined by ELISA method.Four cell lines secreting McABs against wheat G1b-1 protein were obtained, named 1C4，4H5，1A9 and 4F5，respectively. The four McABs belong to IgG1 subtype and their titer was above 9-10. Moreover, all the four McABs specially recognized wheat G1b-1 protein and had no crossreaction with other familiar foods. In order to establish a double-antibody sandwich ELISA system to detect wheat GIB1 proteins, we paired off the four monoclonal antibodies for ELISA assay and found 1C4 and 4h5 might have different epitopes.Four mice anti-wheat G1b-1 protein McABs were prepared successfully and a double-antibody sandwich ELISA method was set up in this work, which may facilitate other wheat allergen protein detection.关键词：antigenic epitope of Glb-1 protein from wheat;monoclonal antibodies;allergen test
- 568
- |
- 295
- |
- 0
发布时间：2023-12-11 - 摘要：Previous paleomagnetic studies have shown that the records of MatuyamaGauss(M/G) reversal event in Chinese loess are asynchronous, some located in loess, while the others located in red clay. This phenomenon will partially lead to the uncertainties in reconstructing the chronology of loess and correlating loess climatic proxies with marine sediments. To clarify our knowledge on the M/G reversal in loess, some representative section studies on the M/G reversal are carefully analyzed in this paper, using the magnetic susceptibilitydepth curve to synthesize the different sections. Comprehensive results show that M/G reversal is generally recorded in loess L33layer, suggesting that the asynchronous feature of M/G reversal record in loess is possibly attributed to the different loess stratigraphic division schemes. According to this idea, the stratigraphic classification scheme of the classic Luochuan and Xifeng loess is partially modified. Finally, the records of M/G reversal in Chinese loesspaleosol are further compared with that of the marine sediments. The perspective of using10Be to trace the M/G polarity reversal in loess is briefly introduced.关键词：Quaternary;Loess layer;geomagnetic polarity reversal;M/G boundary;cosmogenic nuclide10Be
- 575
- |
- 425
- |
- 0
发布时间：2023-12-11 - 摘要：In this paper, Bayesian methods are used to estimate parameters of the stagedischarge power law model in the Dongjiang River, the average low flow, medium flow and high flow uncertainty are calculated and factors affecting the flow uncertainty are analyzed. The results show that: (1) The overall uncertainty of flow data is at a middle-high level, in which high flow uncertainty is maximum, followed by medium and low flow. (2) Human activities, such as construction of reservoirs, river regulation, cofferdams damming, and large-scale mining river sand, have a significant impact on the size and trends of flow uncertainty; the impact of large river floods on hydraulic characteristics and geometric shape is complex, without obvious change in uniform trend.关键词：Bayesian method;stage-discharge relationship;uncertainty;Dongjiang River
- 645
- |
- 301
- |
- 0
发布时间：2023-12-11 - 摘要：It is a common view that climate change has influenced hydrological elements such as precipitation, temperature and river flow. Zhejiang Province has witnessed the climate extremes with high frequency in recent years and it has drawn a lot attention of hydrologists. Low flow hydrology is a very important part of hydrology. It is quite meaningful to analyze the low flow. The historical daily precipitation, temperature and flow in 1975-2004 in the Jinhua River Basin are used as baseline data in this study. Climate projections from Hadgem2_ES of CMIP5 for 2070-2100 are downscaled to stationscale projections based on a multisite statistical downscaling model GIST. The flows in future period are generated by a lumped hydrological model GR4J. Two typical low flow indices 7Q10 and 30Q10 are calculated and compared. The results show that the two indices have obvious rising trends, implying a better situation in low flow periods under climate change.关键词：climate change;low flow;GR4J model;multi-site statistical downscaling
- 612
- |
- 300
- |
- 0
发布时间：2023-12-11 - 摘要：The movement of grain sediment within the bottom boundary layer is influenced by complicated, multi-scale dynamic processes. Dynamic characteristics of turbulence and small-scale sediment exchange process within the bottom boundary layer at modaomen channel are discussed based on bottom boundary layer observation data over various tide levels by using ADV and OBS in winter of 2010. The result shows that: ① The ranges of sediment settling velocity, bottom stress and bed erodibility increase with tidal range.②Bed erodibility changes are similar to mean velocity. When velocity is less than 0.3m/s, the bed erodibility remains at about 0.002 kg/m2. If velocity is larger than 0.3 m/s, sediment will resuspend. ③ Suspended sediment and bed sediment exchange process is enhanced with increasing tidal range, and it is stronger during ebb tide than during flood tide.关键词：bottom boundary layer;sediment exchange;bed erodibility;effective settling velocity
- 526
- |
- 290
- |
- 0
发布时间：2023-12-11 - 摘要：The concepts of generalized frames，generalized frame transform and generalized frame operator and (strong) disjointness of generalized frames in Hilbert K-Modules are introduced. The necessary and sufficient conditions of disjointness of generalized frames in Hilbert K-Modules are given and proven.关键词：Hilbert K-module;generalized frames;generalized frame transform;disjointness
- 466
- |
- 271
- |
- 0
发布时间：2023-12-11 - 摘要：The first eigenvalue of Dirichlet boundary value problem is discussed for a class of WittenLaplacian operators in a bounded open domain Ω ∈Rn. Some better lower bound estimates of these eigenvalues are obtained. And the first eigenvalue of the Dirichlet boundary problem is discussed for another class of Witten-Laplacian operators in the interval (－d,d). The accurate value of these eigenvalues is obtained.关键词：Witten-Laplacian operator;Dirichlet boundary value problem;the first eigenvalue;Riemannian manifold
- 474
- |
- 263
- |
- 0
发布时间：2023-12-11
- Postal code：510275
- Tel：020-84112585，84113223 Email：xuebaozr@mail.sysu.edu.cn
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备09064830号-19
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0