最新刊期
卷 63 ， 期 3 ， 2024
- 摘要：Based on remote sensing images and measurements of soil organic carbon content （including 28 sample sites， 112 soil samples from forests， grasslands， croplands， and construction lands）， methods including Sen's trend analysis， Hurst exponent， partial correlation analysis， and the InVEST model were employed to investigate the spatiotemporal variations in vegetation and carbon storage of the mountainous ecosystem in northeastern Guangdong province. The results show that： （1） The research area exhibits relatively high vegetation coverage， with a Normalized Difference Vegetation Index （NDVI） ranging from 0.14 to 0.95 and an average value of 0.79. From 2000 to 2021， the vegetation coverage of the study region increased. Apart from the city area of Meizhou， the rest showed varying degrees of NDVI increase， especially in mountainous areas， where it showed a trend of rising and subsequently declining with elevation. The Hurst exponent （<0.5） implies a potential declining trend in vegetation changes in the study area. （2） From 2000 to 2020， the carbon storage in the study area displayed a decreasing trend， amounting to a total reduction of 1.33 teragrams （Tg）. Land use changes， particularly the conversion of forests and grasslands into agricultural and urban areas， are the primary reasons for the decrease in carbon storage in the study area. The conclusions can serve as fundamental data for investigating the changes in carbon sequestration functionality within subtropical ecosystems in China.关键词：vegetation changes;carbon storage;NDVI;land use changes;InVEST model;mountainous ecosystems
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发布时间：2024-05-30 - 摘要：The storage of soil organic carbon is a crucial metric for assessing soil nutrients and environmental quality， and it is of great importance for land development， utilization， and achieving carbon neutrality. However， little research has been done on soil organic carbon storage in cultivated land in the red beds region. This study focused on the 0-20 cm surface soil of cultivated land in the red beds region of Lianzhou city， utilizing the ordinary Kriging interpolation method to estimate the density and storage of soil organic carbon. The study analyzed the distribution characteristics and soil carbon sequestration potential as well. The results indicate that overall organic carbon density showed a downward trend from 2007 to 2019. The average organic carbon density decreased from 4.624 kg/m2 to 2.668 kg/m2， and the organic carbon storage decreased from 1.99×109 kg to 1.21×109 kg. The soil carbon sequestration potential was calculated to be 9.42×108 kg. The significant decrease in soil organic carbon storage in the red beds region of Lianzhou city is primarily due to weak irrigation facilities， high intensity of farmland utilization， insufficient fertilizer input， and lack of precise fertilization in agricultural conditions. By improving basic agricultural facilities， reducing abandoned farmland， decreasing high-intensity soil utilization， and scientifically and reasonably applying fertilizers， the organic carbon storage of farmland in the red beds region of Lianzhou city can be increased， promoting the sustainable development of green， low-carbon agriculture in Lianzhou city.关键词：organic carbon density;organic carbon storage;carbon sequestration potential
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发布时间：2024-05-30 - 摘要：Based on hourly precipitation data from 28 rainfall stations in the Pearl River Delta （PRD） region from 2001 to 2012，the accuracy of CMORPH，GPM and ERA5 is evaluated in the PRD on the annual，monthly and daily time scales by calculating 6 statistical metrics and exploring the frequency of different precipitation events. The results show that：（1） Compared with the three time scales of year，month and day，three products showed a highly positive correlation with the measured rainfall station on the monthly scale，but the correlation is weak on the annual and daily scales. （2） At the daily scale，all three precipitation products perform worse in the flood season than in the non-flood season. They are less accurate in detecting precipitation events in dry months than in other months，but the false alarm rate is higher in autumn and winter，and they all have a higher false alarm rate for stations near the coast than for inland stations. （3） In contrast，GPM can more accurately reflect the spatio-temporal trend and spatial distribution characteristics of precipitation in the PRD region. （4） Both CMORPH and GPM show high capacity to estimate various types of precipitation events，which can well reflect the contribution of the measured data to different types of precipitation events. Overall，GPM can best reflect the actual situation in the PRD region among the three products.关键词：precipitation accuracy assessment;CMORPH;GPM;ERA5;the Pearl River Delta
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发布时间：2024-05-30 - 摘要：The Hongwan area in Zhuhai has widespread silt distribution, with specific engineering characteristics of low strength, significant deformation, and poor permeability. Its physical and mechanical properties are crucial for engineering safety. To explore the engineering characteristics of the silt, this study used undisturbed samples taken from the field to conduct laboratory experiments of basic physical property test, one-dimensional consolidation test, and consolidated undrained triaxial test. The results show that the natural moisture content of the soil samples is high, with a significant plasticity index and a hydraulic conductivity k ranging from 3.68×10-7 to 5.86×10-7 cm/s. It is classified as highly compressible soil based on the determined compression coefficient av ranging from 1.269 to 1.618 MPa-1 and a compression modulus Es ranging from 1.449 to 1.919 MPa. With increasing depth, samples show a gradual decrease in the compression coefficient and an increase in the compression modulus. The shear strength of the undisturbed soil samples is relatively low, with a cohesion c range of 10.10 to 20.84 kPa and an internal friction angle φ ranging from 7.28° to 12.09°. With increasing sample depth, the change in the internal friction angle is relatively small, while the cohesion significantly decreases.关键词：silt in Zhuhai;basic physical properties;one-dimensional compression characteristics;triaxial mechanical properties
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发布时间：2024-05-30 - 摘要：To study the influence of buildings layout on the wind environment of residential district，this paper takes a residential district in Zhuhai as the research object. Based on the local climatic characteristics，the PHOENICS software is used to conduct CFD （computational fluid dynamics） simulation of wind environment for two kinds of buildings layout with and without podium buildings. The ventilation conditions and comfort of the two kinds of layout under the background of east，south and north-northeast wind were compared and analyzed，and the results are as follows：1） When there is no podium building，the wind environment of the residential district under the three wind directions are improved without the obstruction of large-scale buildings，the unevenness of the wind speed is reduced，the size and number of areas with good ventilation conditions and good comfort are increased，the size and number of areas with low wind speed are reduced，and the ventilation corridors are increased. 2） Whether there are podium buildings or not，when the angle between the incoming flow direction and the passage of the building is small，the building's wind blocking and weakening effect is small，and ventilation corridors are more easily formed between buildings with better ventilation conditions. When the angle between the incoming flow direction and the passage of the building is large，the building's blocking effect is significant，the wind speed of the residential district is significantly weakened and it is prone to be uneven，so the ventilation conditions are poor. 3） The wind environment of residential district is jointly affected by buildings layout and wind direction，and the local dominant wind should be taken into account in the planning and design of residential district.关键词：residential district;wind environment;CFD simulation;comfort degree;podium building;buildings layout
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发布时间：2024-05-30 - 摘要：Ozone（O₃） has become the primary factor affecting air quality over the Pearl River Delta and even the entire Guangdong Province. Although data-driven statistical models have shown improved forecast capabilities compared to numerical models， most of them operate grid-by-grid and cannot resolve the spatial dependence between site data of non-Euclidean structures. Based on in-situ measurements from national environmental stations and surrounding weather stations in Zhuhai， this study performs hourly O₃ concentration forecasts for up to three days over multiple sites by constructing a graph convolution memory network （GCN-LSTM）. The results show that GCN_LSTM forecasts at different lead times could accurately reproduce the annual， seasonal， and diurnal variations of O3， but the capability of capturing daily variations decreases significantly with the increase in lead time. Further comparisons with the operational numerical model（GRACEs） and Long Short-Term Memory （LSTM） reveal that GCN-LSTM performs the best， with mean RMSE=27.13 μg/m3 and R=0.64， LSTM is the second （RMSE=28.44 μg/m3； R=0.61）， and GRACEs presents distinct results （RMSE = 40.93 μg/m3；R=0.33） in 72h forecasting. Compared with LSTM， GCN-LSTM considers all sites and their interconnections， it not only increases the calculation speed by 71% but also performs better and more stably over different sites. Moreover， it is also optimal for capturing O₃ pollution events in cold seasons. Additional sensitivity experiments reveal that considering more correlated variables improves forecasting capabilities.关键词：ozone（O₃）;spatial-temporal forecast;machine learning;graph convolution memory network
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发布时间：2024-05-30 - 摘要：Studying the soil stoichiometric ratios and the influencing factors of different altitude gradients in mountain ecosystems in arid zones is significant in revealing the soil nutrient status and maintaining the sustainable development of mountain ecosystems. In this paper, 13 sample plots were established along the elevation gradient in the mountains of the southern Ili River Valley, and soil in the depth of 0-20 cm was studied to investigate nutrient stoichiometric ratios and their influencing factors. The results showed that: (1) Soil acidity gradually increased with elevation. Organic carbon and total nitrogen contents are significantly higher in the middle and high mountain belts than in the low mountain belts, while total phosphorus and total potassium contents are opposite. (2) Due to altitudinal differences, the carbon-to-nitrogen ratio is significantly higher in the mid-alpine belt than in the low and alpine belts; carbon and phosphorus ratios are significantly higher in the middle and high mountain belts than in the middle and low mountain belts; carbon and potassium ratios are significantly higher in the middle and high mountain belts than in the low mountain belts; nitrogen-phosphorus ratios are higher in the alpine zone, but there is no major difference between the transition zone and the low mountain zone; nitrogen-potassium ratios are much higher in the alpine zone, whereas there is no significant difference between the mid-alpine zone and the transition zone; the differences of phosphorus/potassium ratios between altitudinal gradients are ignorable. (3) The dominant factors affecting the stoichiometric ratios of soil physicochemical indicators are soil organic carbon (62.4%), total phosphorus (15.9%), and total carbon (13.7%); while the major environmental factors are mean annual soil temperature (27.1%), vegetation index (11.2%), elevation (12.3%), and mean annual atmospheric temperature (3.4%). The study showed that the physicochemical indicators have an important influence on the soil stoichiometric ratio, further verified that the altitude is still the dominant factor affecting the stoichiometric ratio, and revealed that the influence of microenvironmental factors on the soil stoichiometric ratio should not be neglected, which provides a scientific basis for the in-depth study of the nutrient status of soils in mountainous areas of the Ili River Valley.关键词：stoichiometric ratio;impact factor;soil nutrients;Ili River valley mountains
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发布时间：2024-05-30 - 摘要：Few studies have been done on the interspecific relationship between fishes species， an important part of mangrove wetlands. In 2022-2023， a sampling survey was conducted on the mangrove tidal gully fish in the estuary area of Haishan Town， Raoping County， Guangdong Province in spring， summer， autumn and winter， and the composition of fish species in the mangrove wetland was studied. The aim of this study was tried to elucidate the response relationship between the distribution and interspecific relationships of wetland fish and the effects of environmental factors by calculating the spatiotemporal niche width and interspecific overlap values. The results showed that a total of 14 species belonging to 12 families and 6 orders were identified ， including 6 dominant species （IRI≥500）， 3 common species （500>IRI≥100）， 2 rare species （100>IRI≥10） and 3 occasional species （IRI<10）. The spatiotemporal niche width of the fish in mangrove tidal gullies ranged from 0.000 to 2.428， with a large variation range， including 1 species of wide niche species （Bij≥2.0） （Oreochromis niloticus）， 2 species of medium niche species （1.0≤Bij<2.0）（Odontamblyopus rubicundus and Bostrichthys sinensis）， and the remaining 11 species narrow niche species （0<Bij<1.0）. The spatiotemporal niche overlap value between the fish species in the tidal gully of seamount mangrove forest was 0.000-0.956， again with a large variation range， among which 43 pairs （>0.6） were highly significant overlapped （0.6）， accounting for 47% of the total logs， and 21 pairs （0.3< overlap value <0.6） were significant overlapped， accounting for 23% of the total logs， and the two pairs accounted for 70% of the total logs. The highest spatiotemporal niche overlap values were found in Siganus oramin and Periophthalmus cantnensis （up to 0.956）， while the lowest non-overlap values were included in O. niloticus and Platycephalus indicus， B. sinensis and P. indicus， and Paraplagusia bilineata and P. indicus， all with the value of 0. BIOENV analysis showed that the most suitable combinations of environmental factors for fish abundance in the study area were water temperature， salinity， pH and chlorophyll a content， which the correlation coefficient is 0.475， and the RELATE test results were significant （R= 0.461， P<0.05）， indicating that these four environmental factors were important in affecting fish distribution. In general， the spatiotemporal niche of fish in the mangrove wetland of Raoping Haishan town was dominated by narrow niche species， and the spatiotemporal niche overlap between different fish species was significant and meaningful. The water temperature， salinity， pH and chlorophyll a content of the water body were important environmental factors affecting the distribution of fish in the wetland in the forest area.关键词：fish;niche width;ecological niche overlap;spatiotemporal niches;mangrove
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发布时间：2024-05-30 - 摘要：Zhanjiang City， with an area of 37 000 hm2 of mariculture， is an important production and processing base for aquatic products in Guangdong Province and even in the whole country. Conducting carbon sink accounting for mariculture bivalve and seaweed is of great significance， as it will provide data support for Zhanjiang City to conduct fishery carbon sink trading in the future and meet the national carbon neutral demand. Based on the field surveys and laboratory analysis， the key basic data of carbon sink accounting of native bivalve and seaweed in Zhanjiang was obtained in this study. And the carbon sink capacity of mariculture in Zhanjiang based on the whole life cycle carbon emissions of bivalve and seaweed were also evaluated. The results showed that the total carbon sink （measured in CO2） of mariculture bivalve and seaweed in Zhanjiang was 155 436 t in 2021， with bivalve accounting for 155 359 t and seaweed accounting for 77 t. According to the current CO2 trading price in China's blue carbon market， the economic value created by the carbon sinks of bivalve and seaweed in Zhanjiang was 16.48 million RMB. Using the comprehensive method of carbon emission in the whole life cycle assessment， the net carbon sink of the bivalve in Zhanjiang City was 135 176 t， and the seaweed was 39 t. It is evident that Zhanjiang City has a high carbon sequestration capacity in marine bivalve cultivation， which can bring significant economic benefits through emission reduction， and making an important contribution to China's climate change solutions and achieving the "dual carbon" goals.关键词：blue carbon;carbon sink;life-cycle assessment;bivalve;carbon footprint
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发布时间：2024-05-30 - 摘要：The aims of the study was to evaluate dynamic change of volatile oil in the flowers of Citri Grandis Exocarpium（CGE）， and to provide data for application of CGE flower and development of its volatile oil. Prior to ingredient evaluation of the volatile oil by gas chromatography-mass spectrometry （GC-MS）， distillation extraction was conducted on freshly-picked flowers of CGE at four flower development stages （bud initiation， pre-bloom， full-bloom and withered flower）. Activity analysis of volatile oil was then carried out based on network for flower of CGE-activity components-targets. Results showed that volatile oil of CGE flower mainly involve γ-terpinene， D-limonene， linalool， farnesol， nerolidol， β-pinene， alkenes （56.84% ~ 70.19%） and alcohols （21.33% ~ 38.34%）. The alkenes displayed a gradual declination at flower development stages， and the alcohols showed a tendency to increase and then decrease， peaking at full-bloom. The total amount of volatile components kept a high level at bud initiation， pre-bloom， full-bloom stages， and individually decreased at withered flower stages. Farnesol， linalool， α-phellandrene， nerolidol and citronellol， of all the volatile components， has a higher activity in antibacterial and oxidation-resistant properties.关键词：flower of Citri Grandis Exocarpium;volatile oil;dynamic change;GC-MS;activity analysis
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发布时间：2024-05-30 - 摘要：Modern coal chemical industry is an important means to realize the clean utilization of coal resources， the coal chemical sludge generated during the process of coal conversion process is a typical refractory solid waste restricting the development of coal chemical industry since its extremely high water content and the poor dewaterability. It has been documented that the dewaterability of coal chemical sludge is affected by the microbial community structure and water distribution characteristics； and thus， it is necessary to investigate the microbial community information and water distribution in coal chemical sludge to provide theoretical guidance for the high-efficiency sludge dewatering technology. In this study， coal-to-olefins sludge and coal-to-oil sludge were selected and the microbial community structure of the two sludge was obtained through analyzing 16s rRNA gene sequencing， and the water distribution was obtained by DSC and LF-NMR method. The results show that the different sewage treatment processes chosen by two coal chemical industries lead to certain differences in the microbial community structures of coal chemical sludge， Proteobacteria， Bacteroidetes and Chloroflexi are the dominant phylum in the two sludge. The LF-NMR method can more accurately measure the water distribution， and the water in the sludge can be classified into bound water， mechanical bound water and free water according.关键词：coal chemical sludge;microbial community structure;high throughput sequencing;water distribution;low-field nuclear magnetic resonance
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发布时间：2024-05-30 - 摘要：Taking agricultural water use in Emin Irrigation District as the research object， In this study， we applied principal component analysis， information entropy and equilibrium degree to carry out principal component analyze the 10 indicators data of the irrigation district from 2009 to 2021. The result shows that： the main drivers affecting agricultural water use in irrigation districts are six indicators： length of lined impermeable canals， irrigated area， area sown to crops， water-saving irrigated area， volume of irrigation water， and number of people in agriculture. Temporally， the water use composition of Emin Irrigation District from 2009 to 2022 is dominated by agricultural irrigation water， and the water use for irrigation of cropland， garden land， forest land and pasture land accounted is 90.25%， 3.12%， 5.05% and 1.58%， respectively， and the water use for agricultural irrigation showed a decreasing trend year by year from 2010 to 2020. Spatially， the upstream of the irrigation area is dominated by surface water for agricultural water use， and the ratio of surface water and groundwater in the middle and downstream of the irrigation area is basically the same. From 2009 to 2022， the information entropy value and balance degree in different geographical locations of the irrigation area are： downstream > upstream > midstream， and the information entropy of the Northeast， Central， and West are 0.36， 0.32， and 0.56 Nat respectively， and the mean values of the Northeast， Central， and West equilibrium are 0.26， 0.23， and 0.40 ， respectively.The results of the analysis can provide theoretical references for the status quo of water use for irrigated agriculture in the irrigation area and the management of water use.关键词：Emin Irrigation District;agricultural irrigation water use;principal component analysis;information entropy;equilibrium
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发布时间：2024-05-30 - 摘要：A novel coordination polymer ｛［Cd2.5（L）2（bpy）2Cl（NO3）（H2O）3］·（NO3）·2H2O｝ was constructed by self-assembly at room temperature using a mixture of N containing rigid ligand 4，4'- bipyridine （bpy）， zwitterionic ligand 4-carboxyl-1- （3-carboxybenzyl） pyridin-1-onium chloride （H2LCl） and Cd2+ using liquid phase diffusion method. The structures and properties of the coordination polymer were analyzed by single crystal X-ray diffraction， Hirshfeld surface and two-dimensional fingerprint， powder X-ray diffraction， thermogravimetry， and solid fluorescence. The results showed that the coordination polymer is a one-dimensional ladder shaped chain composed of ［Cd（bpy）2］ symmetric rod-shaped unit and two parallel ring chain structures. By abundant intermolecular interactions （π···π stacking interactions， O—H···O， and C—H···O hydrogen bonding）， the ladder shaped chains penetrate parallel and stack with each other， ultimately forming a stable three-dimensional supramolecular structure. In addition， due to the presence of d10 metal ions， the coordination polymer exhibits a similar but enhanced light green fluorescence to the ligand H2LCl in the wavelength range of 425-466 nm， with CIE coordinates is （0.287 0， 0.334 6）.关键词：coordination polymer;crystal structure;liquid phase diffusion method;intermolecular interactions;solid state fluorescence
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发布时间：2024-05-30 - 摘要：In this paper， hydroxyapatite （HAP） was synthesized by clean and simple multi-scan cycle voltammetry. The crystal structure and functional group of intermediate products calcium hydrogen phosphate dihydrate （DCPD） and hydroxyapatite（HAP） were characterized by X-ray diffraction and infrared spectroscopy. Scanning electron microscope showed that the surface of HAP was a rod-like structure with good dispersion. Taking fluorine ions in water as adsorption objects， the effects of the parameters such as pH， possible coexistence anions and temperature on the adsorption capacity of synthesized HAP were studied. The results showed that in the range of pH of 3-6， the adsorption capacity of HAP to fluorine ions gradually increased with the increase of pH and reached the maximum when the pH was 6； in the range of pH of 6-10， and the adsorption of HAP to fluorine ions gradually decreased with the increase of pH. Anions that may coexist in water， such as Cl-、 NO
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发布时间：2024-05-30 - 摘要：The rapid development of modern agriculture generally relies on the massive use of pesticides， which also become the main organic pollutants in the environment due to the structural stability and high toxicity effects of pesticide molecules. In this study， IRMOF-3 with high fluorescence efficiency was prepared by a simple and rapid room-temperature synthesis method， and then applied to the fluorescence detection and analysis of the toxic neonicotinoid pesticide， nitenpyram （NIT）. The results show that the prepared IRMOF-3 is a pure-phase crystalline material with stable photoluminescence at 427 nm； The blue fluorescence of IRMOF-3 can be quenched quickly by NIT in the aqueous environment， which shows a good selectivity and a strong anti-interference ability among many interferences. The fluorescence analytical method developed by this method showed a significant correlation in the concentration range of 0~38 μmol/L of NIT， and the limit of detection（LOD） was as low as 0.35 μmol/L. The spiked recoveries demonstrated that the method had good recoveries （95.16%~106.51%） with the relative standard deviations（RSDs）≤ 6.68%. The analysis of the multiple characterization results indicated that the fluorescence detection mechanism mainly refers to the energy competition absorption of NIT for the excitation light. In addition， the fluorescence quenching due to electron transfer is also one of the fluorescence detection mechanisms of IRMOF-3 for NIT. In conclusion， IRMOF-3 based on fluorescence analysis has realized the detection of NIT with high sensitivity， which provides a simple and reliable analytical method for the future detection of NIT-type pollution in water environment.关键词：IRMOF-3;nitenpyram;fluorescence detection;energy competition absorption;electron transfer
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发布时间：2024-05-30 - 摘要：This study focuses on synthesizing ultrafine platinum nanoparticles (Pt/C60-E) by irradiating a mixture of C60 and K2[PtCl4] with ethylene glycol (EG) as the reducing agent. The process utilizes near-ultraviolet (UV) light at a wavelength of 395 nm, along with visible light at 450 and 650 nm. The composition and morphology of the Pt/C60 catalyst were investigated using characterization techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HR-TEM). The results revealed a well-dispersed distribution of Pt nanoparticles on the C60 surface, with an average particle size of about 2.6 nm. In the catalytic reduction experiments of p-NP, the Pt/C60-E3 catalyst, prepared under near-ultraviolet irradiation (395 nm), exhibited superior catalytic activity, with a rate constant (k) of 0.12 min-1. Furthermore, in the catalyst cycling experiments, the catalysts remained highly active even after multiple cycles, demonstrating the effectiveness of the photochemical method in synthesizing precursor Pt catalysts.关键词：platinum ultrafine nanoparticles;fullerene;photochemical method;degradation of p-nitrophenol
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发布时间：2024-05-30 - 摘要：A describing function method with balancing in time domain （DFBT） is used to efficiently solve 2-DOF airfoil system with nonlinear energy sink （NES）. This method uses a set of basis functions to describe the periodic motion， discretes the dynamic equation in time domain and lists the equilibrium equation point by point to solve the basis function and obtain the harmonic coefficient. The point-by-point equilibrium equation obtained by discretization can provide overdetermined algebraic equations for solving harmonic coefficients， and the iterative convergence can be easily combined with minimum optimization.The method does not need to switch the time-domain and frequency-domain responses of the nonlinear system frequently， which brings convenience to the solution. The results of the solution agree well with those of the numerical method， which verifies the effectiveness of the method. At the same time， due to the semi-analytic form of DFBT results， the unsteady solution of the flutter system and the complete subcritical bifurcation diagram can be obtained. Therefore， DFBT is suitable for solving the steady-state response of multi-degree-of-freedom flutter systems with complex nonlinearity.关键词：nonlinear flutter system;limit cycle;nonlinear energy sink;semi-analytic method
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发布时间：2024-05-30 - 摘要：The composition and formation behavior of each component of decommissioned
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发布时间：2024-05-30 - 摘要：In order to improve the solution precision of the plane problem， the Q8_Legendre element is constructed based on the idea of introducing Bubble function to enhance the mapping relationship based on Legendre orthogonal function. Because the displacement field of the element contains Bubble function， the size of the element stiffness matrix becomes larger. In order to reduce the size of the overall stiffness matrix and save the computer memory space， the additional degrees of freedom are condensed after the stiffness matrix of the element is obtained. Some numerical examples show that the Legendre element can pass the patch test， and the displacement accuracy of the element is improved with the increasing of Bubble function number， while the stress accuracy remains almost the same. When the distortion mesh is encountered， the Q8_Legendre element exhibits the performance of anti-distortion ability， and locking phenomenon does not appear.关键词：plane problem;Bubble function;displacement correction model;Gauss quadrature;anti-distortion
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发布时间：2024-05-30 - 摘要：The inverse scattering problem for obstacles and cavities with Neumann boundary conditions is studied by using the factorization method. The data from near-field measurements is used to deal with both inverse scattering for obstacles and cavities without making any asymptotic assumption about the distance between the measured surface and the scatterers. Firstly， mathematical model for the inverse scattering problem is given， and the results of the estimation of the double-layer operator are given by using the jump relation of the double-layer potential and Green's formula. Secondly， the decomposition of the near-field operators of obstacles and cavities is studied separately. Finally， the imaging function of obstacles and cavities under Neumann boundary conditions is constructed.关键词：inverse scattering;near-field measurements;the factorization method
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发布时间：2024-05-30
Research articles
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