最新刊期
卷 56 ， 期 4 ， 2017
- 摘要：Fortran language has high execution efficiency. It is widely used in the field of numerical calculation. And it has accumulated a lot of highefficient and reliable source codes. For example, The Microsoft IMSLFortran Library can give powerful mathematical and statistical analysis. VB.NET is a fully objectoriented language. Compared against VB language, VB.NET is quicker and easier to develop a more powerful Windows program. Mixedlanguage programming of VB.NET calling Fortran through dynamic link library mode is studied. It gives the corresponding calling method for variable, string, array, structure and structure array. Also the typical examples are offered. It provides technical support for the development of software with both advantages of Fortran and VB.NET: high execution efficiency and quick and easy development ability.关键词：Fortran;VB.NET;mixed-language programming
- 288
- |
- 225
- |
- 0
发布时间：2023-12-11 - 摘要：The labeling of Graph is an important branch of the graph theory. Two kinds of new graphs, cyclic-dragon graphs and haired cyclic-dragon graphs, are defined. It is proved that they are odd-graceful. The haired cyclic-dragon graphs is made by adding leaves to cyclic-dragon graphs, so they inherit the odd-graceful property of cyclic-dragon graphs, whose method can algorithm that may be a theoretical guarantee for applying cyclic-dragon graphs and haired cyclic-dragon graphs to network.关键词：cyclic-dragon graphs;haired cyclic-dragon graphs;set-ordered odd-graceful labeling;odd-graceful labeling;leaf;odd-graceful graph
- 238
- |
- 169
- |
- 0
发布时间：2023-12-11 - 摘要：In order to further impoove noisy image fusion effect, a novel fusion method for noise image based on shearlet transform and sparse representation is presented. The proposed scheme performs the four stages: ① Perform a shearlet transform decomposition of each source image and obtain their low-pass and high-pass coefficients; ② Obtain the fused shearlet transform coefficients in the low-pass bands with a sparse representation based fusion approach while in the high-pass bands by fusing the largest absolution values; ③ The hard thresholding is applied to the fusion shearlet transform coefficients. ④ The result image is obtained by the inverse shearlet transform. Experimental results show that the proposed algorithm for image fusion is very effective.关键词：image fusion;shearlet;sparse representation;multi-scale transform
- 217
- |
- 211
- |
- 0
发布时间：2023-12-11 - 摘要：The global stability of the endemic equilibrium of a fractional order SIR model with birth and death on complex networks is studied. Under some additional conditions, the problem is discussed. It is proved by constructing a Lyapunov function that without any additional condition, the endemic equilibrium is globally asymptotically stable. The result improves previous work.关键词：complex networks;fractional order differential equation;global stability;Lyapunov function mehtod
- 186
- |
- 169
- |
- 0
发布时间：2023-12-11 - 摘要：A first-order discrete fractional boundary value problem with semipositone nonlinearity is studied. By virtue of some inequalities associated with Green function, and using the fixed point index, the existence of positive solutions is obtained for the problem, with the nonlinearity grows both superlinearly and sublinearly. The results extend known results.关键词：discrete fractional boundary value problem;fixed point index;positive solution;semipositone nonlinearity
- 250
- |
- 169
- |
- 0
发布时间：2023-12-11 - 摘要：Under inflation influence, an optimal time-consistent strategy selection problem for claims dependent risk model is studied. The two claim number processes are correlated by a common Poisson process. The insurer can purchase reinsurance for reducing claims and invest its surplus in finance market for increasing wealth. In the process of investment, the effect of inflation is taken into account, and the effect of inflation is achieved through the conversion of the risk asset to the inflation rate. The objective of the insurer is to choose an optimal time-consistent reinsurance-investment strategy so as to maximize the expected terminal surplus while minimizing the variance of the terminal surplus. Since this problem is time-inconsistent, it is studied by placing the problem within a game theoretic framework. Applying Hamilton-Jacobi-Bellman dynamic programming approach, closed form solutions for the optimal reinsurance-investment strategy and the corresponding value functions are obtained. Finally, the influence of some insurance market model parameters on optimal reinsurance strategy is explained by numerical calculation, and the influence of financial market model parameters and inflation model parameters on optimal investment strategy are also given. Through this study, it can guide investors to make reasonable investment under the influence of inflation, so that their wealth is the largest and the smallest risk.关键词：inflation;mean-variance criterion;reinsurance-investment;claims dependent;time-consistent
- 206
- |
- 160
- |
- 0
发布时间：2023-12-11 - 摘要：Polycrystalline silicon (poly-Si) thin films have been widely used in flat panel displays, MEMS(micro-electro-mechanical system) and integrated circuits, and also have great application prospects in other areas such as solar cells and SOP (system on panel). Since there exist grain boundaries (GBs) in poly-Si thin films, the crystal defects and dangling bonds in GB regions would introduce interface states in the band gap. On the one hand, the interface states would trap carriers thus creating barriers against carrier transportation, on the other hand, they could act as effective recombination centers to strengthen the recombination. Therefore, the performance of devices fabricated on poly-Si thin films is generally worse than that on single-crystal silicon thin films. To give a theoretical explanation on the electrical properties of poly-Si thin films under the dark and illumination conditions, various theoretical models have been proposed. In addition, two kinds of ways including analytical method and computer simulation have been developed to determine the energy distribution of interface states in the band gap. This article will briefly review the major research progress in electrical transport theory of poly-Si films and methods for determining the distribution of the interface states, so that researchers engaging in investigation on transport properties of poly-Si thin films or polycrystalline semiconductors could get some reference and inspiration.关键词：polycrystalline silicon thin film;grain boundaries;interface states;electrical properties
- 205
- |
- 183
- |
- 0
发布时间：2023-12-11 - 摘要：A two-step method is proposed to solve structural damage identification problem. First, the improved residual vector is used to locate the general damage range, and then used Tree-seed algorithm (TSA) is used to identify damage extents based on objective function related to damage structures. TSA is a heuristic algorithm with simple structure and easy to implement. In order to make it more powerful, two kinds of search modes and a self-adaptive judge factor are utilized to realize algorithms search. A beam and a plate are employed as numerical simulations. Studies show that the present techniques can produce more accurate damage identification results, comparing with other algorithms, even with a little noise contaminated measurements.关键词：TSA;residual vector;beam;plate;frequency domain.
- 190
- |
- 178
- |
- 0
发布时间：2023-12-11 - 摘要：In the study on the reliability of link travel time, the delay of intersection queue is set up with fixed delay value, and the dynamic analysis of the intersection delay under the condition of stochastic road network is lacking. Aiming at the time-varying road network, according to the operational characteristics of traffic flow, considering the interaction of passengers and traffic, considering the mutual influence of vehicle queuing, signal phase, and traffic speed, stochastic dynamic link travel time reliability under different road service level can be fixed. The results show that the travel time with stochastic dynamic intersection delay is highly reliable.关键词：service level;stochastic dynamic;travel time;reliability
- 234
- |
- 162
- |
- 0
发布时间：2023-12-11 - 摘要：According to the actual conditions, a switched system model and a control strategy based on the output feedback switching strategy method are proposed for a semi-active suspension system in this work. On the basis of this, in order to further analyze the control effect of the control strategy, a road roughness is produced based on the rational function filter white noise generation method, then analysis and comparison simulation about the vibration produced by the road roughness are carried out by MATLAB／Simulink. The simulation results show that compared with the passive suspension, the low-frequency semi-active suspension control strategy based on switching control is 22% lower, the suspension deflection is 36% lower, and the tire dynamic load is 13% lower. The results show that the low frequency semi-active suspension control strategy based on switching control can improve the dynamic performance of the vehicle and improve the ride comfort and handling stability of the vehicle.关键词：semi-active suspension;switching system;pavement roughness;dynamic performance
- 217
- |
- 166
- |
- 0
发布时间：2023-12-11 - 摘要：The problem of self-adaptive sliding mode chaos synchronization of fractional-order uncertainty duffling systems based on a new reaching law is studied in the paper. The sliding mode functions and controllers are given out using self-adaptive sliding mode approach and got the sufficient conditions for the master-slave systems getting sliding mode synchronization . It is proved that master-slave systems are sliding model chaos synchronization under proper controllers and sliding mode surface. The strict deduce and proof in mathematics are given out in the paper. Numerical simulations examples of chaotic system verify the effectiveness of the proposed method.关键词：fractional-order Duffling systems;self-adaptive sliding mode;chaos synchronization
- 201
- |
- 162
- |
- 0
发布时间：2023-12-11 - 摘要：A new crack detection method for bituminous pavements based on cluster and minimum spanning tree is proposed in this paper. Firstly, the Retinex model was used to dodging preprocessing for crack images, to reduce the difference of different lighting conditions, and then the edge detection and image segmentation technology was both used for extracting the crack area in the image, finally the clustering and minimum spanning tree technology was used for crack detection. The test images used in this study are captured from actual traffic intersections. The experimental results show that the method can accurately and effectively detect the crack for bituminous pavements, and can be applied on real traffic scene with considerable practical value.关键词：crack detection;dodging algorithm;clustering technology;minimum spanning tree
- 163
- |
- 207
- |
- 0
发布时间：2023-12-11 - 摘要：The chiral conversion mechanism and water solvation effect of three kinds of the most stable configurations of tyrosine molecules were researched by using the B3LYP method of density functional theory, the MP2 method of perturbation theory, and smd model method of self consistent reaction field theory. The study of reaction channels shows that there are three channels a, b and c in the title reaction. For the configuration one and two, the proton of the chiral carbon is transferred with amino group after the carboxyl cistrans isomerism, amino group and carboxyl/amino groups as the bridge, respectively. For the configuration three, the proton is transferred with amino group and carboxyl/amino groups as the bridge, and transferred proton of the carboxyl is transferred with amino group as the bridge, respectively. Calculations of potential energy surface show that channel a is the dominant reaction path in the configuration one and two, stepdetermining gibbs free energy barriers are 257.0 and 264.0（kJ·mol-1），respectively. In addition, channel b and c are the dominant reaction paths in the configuration three, step-determining gibbs free energy barriers are 257.4 and 257.0 kJ·mol-1which are generated by the transition state of proton transfer from the chiral carbon to the amino N. The water solvation effect enables the stepdetermining energy barrier is reduced to 113.1 kJ·mol-1for the dominant reaction path in the configuration one. The results show that: monomer tyrosine molecule is stable, tyrosine chiral conversion can be proceeded slowly in water environment.关键词：tyrosine;chirality;density functional theory;transition state;perturbation theory;SCRF
- 218
- |
- 154
- |
- 0
发布时间：2023-12-11 - 摘要：Low-cost and high performance electrocatalysts toward oxygen reduction reaction (ORR) is important for novel energy systems, such as proton exchange membrane fuel cells, direct methanol fuel cells, and etc. In this work, a N and S codoped porous grapheme-like catalyst was obtained using polyacrylonitrile and sulfur as precursors through a facile pyrolysis procedure. The catalyst exhibited excellent performance in alkaline medium, with a half-wave potential 32 mV more positive than that of commercial Pt/C catalyst. Beside excellent ORR performance, the catalyst also exhibited outstanding methanol tolerance, stability, as well as high catalytic efficiency. By studying the relationship among catalysts structures, compositions and its catalytic performance, we found that the unique compositions, morphologies and porous structures induced by sulfur addition should be the origin to the catalysts high ORR performance.
- 186
- |
- 206
- |
- 0
发布时间：2023-12-11 - 摘要：To investigate the secondary metabolites from the marine sponge Hyrtios sp. of South China Sea, seven compounds were isolated from the dichloromethane extraction of Hyrtiossp. by Silica gel, ODS and HPLC. Their structures were identified by spectroscopic analysis and comparison with the literature as smenospongimine (1), smenospongiarine (2), sesquiter-penyl-amyl-amino-hydroxy-quinone (3), smenospongidine (4), dictyoceratin C (5), dictyoceratin A (6) and polyfibrospongol A (7), respectively. Compounds 1，2，3，4，5，6，7 were isolated from the genus of Hyrtios for the first time.关键词：Hyrtios;secondary metabolites;identification
- 251
- |
- 185
- |
- 0
发布时间：2023-12-11 - 摘要：With the co-action of NH3and urea, TaON nano-photocatalyst was successfully synthesized within shorter time using the amorphous Ta2O5·nH2O compound as precursor, which was prepared by optimized treatment of commercial Ta2O5. The results indicated that TaON semiconductor present special structure with amounts of pores like honeycomb, and its specific surface area was 6 times higher than that of traditional TaON. For the photocatalytic performance, multihole TaON showed a certain ability of photocatalytic selective oxidation of benzyl alcohol. Such property could be improved with the coaction of Pd and Ag.关键词：nitrogen oxygen tantalum;selective oxidation;photocatalysis
- 238
- |
- 185
- |
- 0
发布时间：2023-12-11 - 摘要：The naringin's influence on the protein expressions in the lung tissues of cigarette smoke induced acute lung inflammation in mice was examined by iTRAQ technology. Twenty Balb/c mice were randomly divided into the model group and the naringin group with ten mice in each group. Naringin was administered by gavage at a dose of 60 mg（·kg-1·d-1） before smoke treatment, while mice in model group were given normal saline. All mice were sacrificed 16 h after the last smoke treatment. The lung tissues were collected and analyzed by iTRAQ technology. Differentially expressed proteins were screened through identification and quantification analysis. As a result, a total of 3 528 proteins were identified, of which 64 proteins were differentially expressed after administration of naringin, including 29 up-regulated and 35 down-regulated proteins. Bioinformatics analysis indicated that these differentially expressed proteins were mainly associated with the release of inflammatory mediator nitric oxide and the metabolism of pro-oxidant agent homocysteine. These may provide an important contribution to naringin's effects on the protection of lung tissue injury caused by inflammation and promotion of inflammation resolution. Arg1, Bhmt and Dnmt may play important roles in the therapeutic effects of naringin on the lung inflammation diseases. The present study could provide a useful basis for the mechanism study of naringin.关键词：naringin;iTRAQ;lung inflammation;protein expressions
- 252
- |
- 173
- |
- 0
发布时间：2023-12-11 - 摘要：In order to enhance the activity of pyrethroid degrading enzyme, error prone PCR technology was used to modify a novel esterase gene (est825) which was derived from marine sediment metagenomic library. A mutant enzyme EstM46 was cloned and characterized. The activity of EstM46 was 1.5-fold higher than wild type (Est825), and the optimum temperature was 5 degrees higher than that of Est825. Furthermore, the mutant enzyme stayed stable up to 70 ℃, remaining 80% (50% with Est825) of its activity after incubated at 70 ℃ for 2 h. The hydrolysis rates of cyhalothrin, cypermethrin, sumicidin and deltamethrin were 92.21%, 99.75%, 93.21% and 89.48%, respectively. A broad-spectrum pyrethroid-degrading enzyme with higher hydrolytic activity and more thermostability will play a better role in practical biodegradation.关键词：pyrethroids;pesticide degradation enzyme;directed evolution;biological degradation
- 231
- |
- 146
- |
- 0
发布时间：2023-12-11 - 摘要：CVN (Cyanovirin-N) is a highly potent anti-HIV protein. Cyanovirin-N homology (CVNH) family is a homologous protein to CVN, which exhibits a common fold structure similar to CVN and possess a highly conserved anti-HIV CVN domain. In this study, DNA encoding sequences of the wildtype and mutant CtCVNH from Ceratopteris thalictroides were separately cloned into eukaryotic expression vector pPICZαA. All wCtCVNH and mutated mCtCVNH genes produced two bands corresponding to 22 000 and 24 000, which were validated by western blot. The proteins were purified by ultra-filtered centrifugation and Ni-NTA affinity chromatograph. Glycosylation assay further confirmed that no N-glycosylation site occurred in wCtCVNH protein. The possible reasons were ascribed to incomplete cleavage of the α-factor signal peptide sequence in vector pPICZαA or some other post-translational modifications rather than N-glycosylation. The study laid a solid foundation for further exploring the pharmacokinetics and pharmacodynamics of CtCVNH in future.关键词：anti-HIV protein;Ceratopteris thalictroides;mutant;Pichia pastoris
- 207
- |
- 147
- |
- 0
发布时间：2023-12-11 - 摘要：The purpose of the study is to screen and identify amylase producing bacteria in the Black Lake in Yuli county, and to optimize the conditions of enzyme production. A high amylase producing strain HM-22 was screened from 43 strains of bacteria, has carried out morphological identification, molecular identification of 16S rDNA and optimization of enzyme production conditions were carried out. 43 strains of bacteria were isolated from 30 water, soil and mud samples in the Black Lake in Yuli County, and 14 strains producing amylase were screened out. The enzyme activity was determined by Yoo method, a strain with high enzyme activity was obtained and named as HM-22. By gram staining, colony morphology observation, physiological and biochemical tests, 16S rDNA sequence alignment and the similarity of Bacillus tequilensis was 99.8%, belonging to the genus Bacillus. The optimization of enzyme production conditions of strain HM-22 was determined and the best condition for producing the enzyme is: the optimum temperature of amylase production was 40 ℃, the optimal carbon source is soluble starch, the optimal nitrogen source was beef extract, the optimum reaction pH was 6.0, the optimum culture time was 24 h. After optimization, the enzyme activity of strain HM-22 reached 147.53 U/mL from the initial activity of 122.45 U/mL, enzyme activity increased by 17%. The study provides a theoretical basis and reference for the screening of strains with high amylase activity in Xinjiang salt lake bacteria
- 225
- |
- 177
- |
- 0
发布时间：2023-12-11 - 摘要：The newlydiscovered Huangnikeng gold deposit is located in the GuangningLuoding fault zone, southern section of the Qinzhou-Hangzhou Metallogenic Belt (QHMB). In view of the research blank of this gold deposit, the petrography observation combining with SEM-EDS analysis are applied to obtain its mineral sequences. The wall rock of the Huangnikeng gold deposit is composed of the sandstone of the Cambrian Shuishi Formation with greenschist facies metamorphism including chloritization, sericitization and carbonation. The ore minerals consist of electrum, pyrite, arsenopyrite, sphalerite, galena, chalcopyrite, polybasite and molybdenite, etc., whilst the gangue minerals are dominated by quartz, chlorite, sericite, carbonate minerals, rutile, apatite, zircon, monazite, etc. Based on minerals cross-cutting relation and mineral assemblage, four main ore-forming stages are identified, including: ① the stage A of chloritizationsericitization；② the stage B of pyrite-arsenopyrite-polymetallic sulphides；③ the-stage C of pyrite-arsenopyrite-electrumc；④ the stage D of carbonatization. The most important economic mineral is electrum of the stage C distributed in particles and fractures of pyrites and arsenopyrites. The geological characteristics and mineral sequences of the Huangnikeng deposit are accordant to the global orogenictype gold deposits. Therefore, the Huangnikeng gold deposit can be considered as an example of orogenictype gold deposit in the southern section of QHMB.关键词：Huangnikeng gold deposit;Qinzhou-Hangzhou Metallogenic Belt (QHMB);mineral sequences;SEM-EDS analysis;orogenic-type gold deposit
- 195
- |
- 216
- |
- 0
发布时间：2023-12-11 - 摘要：The ancient stress factors since the Indosinian movement in Rencha basin and its adjacent area have been recovered based on joint screening and statistical analysis. The Rencha region was squeezed by the northsouth stress during the Indosinian time, accompanying the formation of a series of eastwest folds and crust thickening. A series of sagtype basins began to form and accept deposition in the early Yanshan orogeny, but the northsouth extension led to instability induced by gravity and the embryonic formation of a NNE downfaulted volcanic basin in late Yanshan period. In the Eocene, the basin turned to uplifting and eroding stage, forming a modern tectonic pattern, with the east higher than the west. According to the regional stress analysis and geological characteristics, tectonic evolution model of the Rencha Basin was constructed. In the end, a preliminary fault system evolution of the Rencha Basin was carried out and the relationship between the fault system and uranium mineralization was proposed based on the deformation analysis.关键词：tectonic evolution;tectonic mechanism;uranium mineralization;Rencha Basin
- 204
- |
- 216
- |
- 0
发布时间：2023-12-11 - 摘要：On basis of daily precipitation data from 12 raingauge stations over the CircumBeibuGulf region of Guangxi from 1961 to 2011, the spatialtemporal variation characteristics of precipitation pattern were analyzed. The incidence rate and contribution rate of precipitation are defined and used to assess the spatial and temporal variation of precipitation pattern. And the MannKendall test method is used to discuss the trend of precipitation pattern. The results show that: ① The incidence rate of precipitation events for different durations decreases exponentially with the increase of precipitation durations, while the corresponding contribution rate firstly increases and then decreases; As far as disaster is concerned, precipitation events for 3~4 d are most likely to trigger flood disaster. The spatial distribution of precipitation events for different durations has a similar variation trend such as 1~2 d and ≥10 d with great difference and 3~9 d with little difference. ② The incidence rate for different grades decreases with the increase of precipitation grade, while the corresponding contribution rate is increasing；The incidence rate and the contribution rate of light rain events are lower in southern region (Bei hai, Qinzhou and Dongxing), while torrential rain events are higher than other regions. ③ Precipitation events for different durations throughout the region have a similar variation trend such as 1~2 d and ≥6 d showing a downward trend and 3~5 d showing an upward trend. Light, heavy and torrential rains throughout the region have a similar variation trend such as heavy and torrential rains with an upward trend and light rain with a downward trend; while the opposite trend is found for the incidence rate and the contribution rate of moderate rain events, showing upward and downward trends, respectively.关键词：incidence rate of precipitation;contribution rate of precipitation;precipitation duration;precipitation grade;Circum-Beibu-Gulf region of Guangxi
- 213
- |
- 158
- |
- 0
发布时间：2023-12-11 - 摘要：The Pearl River estuary is distinguished from other estuaries by its numerous rocky islands and complicated topography. Its energy dissipation and mechanism induced by island topography were studied based on three dimensional turbulent model in this area, including the dynamic structure, turbulence characteristic, energy transformation, energy dissipation in different local areas. The results showed that island-induced energy dissipation can be divided into branch zone, turbulent mixing zone, upstream zone and downstream zone, and their dynamic balance is between pressure term, horizontal advection term and turbulent stress term in the turbulent mixing zone, and between pressure term and horizontal advection term in the other zones.关键词：island morphological unit;the average flow and turbulent flow;turbulent energy dissipation;subarea of the energy dissipation zone
- 173
- |
- 187
- |
- 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