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1.
Soil salinity and waterlogging are two major environmental problems in estuarine wetlands. The objective of this study was to investigate the effects of salt stress, water table, and their combination on growth, chlorophyll content, antioxidant system, and ion accumulation in Suaeda salsa plant, which is the pioneer plant in coastal wetland of the Yellow River Delta (YRD). The results showed that plant height, number of branches, and biomass were significantly affected by water table and salt stress. With enhanced salt stress, the ratio of leaf to total biomass increased and the ratio of root to total biomass decreased. The contents of Chl‐a, ‐b, Chl‐a + b, and carotenoids (Car) decreased significantly with increasing soil salinity and the water table level. Salt stress enhanced the activity of superoxide dismutase (SOD) and catalase (CAT), but reduced the content of protein. With the lowering water table level, the activity of CAT and protein content increased, and activity of SOD decreased. Na+ and Cl? content were up‐regulated with increasing salt stress (NaCl), whereas, the contents of other cations (K+, Ca2+, and Mg2+) and anions ( and ) were decreased. In summary, the results indicated that the S. salsa plants could adapt to the adverse soil environments through modifying their growth and physiology status at the highly saline and intertidal zone, such as the YRD estuarine wetlands, and also could be used as a bio‐reclamation plant to decline the high salt in saline soils.  相似文献   

2.
In the present work, experiments have been carried out with a focus to reduce the volume requirement of solvent by mixing with imidazolium based ionic liquids (ILs) for the solvent extraction of phenol, p‐chlorophenol, 2,4‐dichlorophenol, 2,4,6‐trichlorophenol, and pentachlorophenol from aqueous solutions. The effect of aqueous phase pH (2–12), agitation speed (100–450 rpm), solute concentration in feed (2–50 mg/L), temperature (303–333 K), treat ratio (1–11), and 1‐butyl‐3‐methyl imidazolium tetrafluoroborate [Bmim]+[BF4]? volume in tributyl phosphate (TBP; 0–0.7% v/v) on extraction of phenols has been studied and optimized. Parameters like strip phase pH (3–13) and stripping agent concentration (0.001–0.009 N) have also been studied for stripping of phenols from solvent phase. It has been found that 0.5% v/v of ionic liquid [Bmim]+[BF4]? in solvent TBP extracts more than 97.5% of phenol and chlorophenols from aqueous solutions with a treat ratio (aqueous to solvent phase ratio) of 5. Transport mechanism for extraction and stripping of phenol and chlorophenols using ionic liquid [Bmim]+[BF4]? has been discussed. The results show that by appropriate selection of extraction and stripping conditions, it is possible to remove nearly all phenols with a treat ratio of 5.  相似文献   

3.
An optimized analysis method based on headspace liquid phase microextraction (HS‐LPME) and gas chromatography coupled with mass spectrometry was proposed for the determination of trihalomethanes (THMs) in drinking water. The response surface method (RSM) was used to optimize the extraction of THMs for analysis by HS‐LPME. The temperature, extraction time and NaCl concentration were found to be important extraction parameters. The coefficient of determination (R2) for the model was 94.97%. A high probability value (P < 0.0001) for the regression indicated that the model had a high level of significance. The optimum conditions were seen to be: temperature 42.0°C, NaCl concentration 0.30 g/mL, and extraction time 28 min. The response variable was the summation of the THMs chromatography peak areas and the reproducibility of this was investigated in five replicate experiments under the optimized conditions. The relative standard deviations (RSD%) of the THMs ranged from 8.0–11.6%. The limits of detection (LODs), based on a signal‐to‐noise ratio (S/N) of three ranged from 0.42–0.78 μg/L, and were lower than the maximum limits for THMs in drinking water established by the WHO.  相似文献   

4.
The organic composition and organic‐inorganic interaction in paper mill sludge (PS) solvent extracts (hexane, ethyl acetate, acetone and ethanol) and humic fractions, humic acid (HA) and humin (HU) were studied by electron paramagnetic resonance spectroscopy (EPR), proton and carbon‐13 nuclear magnetic resonance spectroscopy (1H NMR; 13C NMR), Fourier‐transformed infrared spectroscopy (FTIR), and ultraviolet‐visible spectroscopy (UV‐vis). The strategy of fractionating the PS, sequentially, with organic solvents of increasing polarity is a reliable analytical procedure for humic substance sample separation because it results in more purified fractions. FTIR, 1H NMR and 13C NMR results showed that hexane extract consisted mainly of aliphatic hydrocarbon structures. Their contents in the extracts decreased as the polarity of the extracting solvent increased and the content of oxygen functional groups increased. Carboxylic and carboxylate functional groups were found in the acetone extract, and ester and ether functions were predominantly found in the ethanol extract. EPR spectra revealed some Fe3+ complexes with rhombic structure (g1 = 4.3; g2 = 9.0) in the humic fractions and in all solvent extracts, except hexane. Quasi‐octahedral Fe3+ complexes (g = 2.3; ΔHpp ≤ 400 G) were found in the HU fraction and in the acetone extract. The organic free radical content in the HA fraction was higher than the non‐fractionated PS sample and HU fraction.  相似文献   

5.
Sedimentary pigments are useful proxy indicators of phytoplankton biomass, community structure, primary productivity and human influence in lacustrine and oceanic ecosystems. Pigments are relatively labile due to their complex chemical structures, which makes the extraction and analysis of sedimentary pigments challenging. In addition, it is important to select appropriate methods to study sedimentary pigments in regions which lack previous investigations. In this study, we adopted the L_9(3~4) orthogonal design to develop methods of extraction and HPLC(high performance liquid chromatography) analysis of sedimentary pigments at two lakes on the Tibetan Plateau: meromictic lake-Dagze Co and dimictic lake-Jiang Co. The orthogonal design comprises 9 combinations of various parameters for extraction and HPLC analysis. The results show that the type and volume of solvent are the most important factors for pigment extraction, and the mobile phase and column selection are the most important for HPLC analysis. For the study sites, we found that the best methods to extract sedimentary pigments are as follows: the use of a mixture of acetone:methanol:water(80:15:5, v:v:v) as the extraction solvent; solvent/sample ratio of 10 m L/g; sonication for 30 s and standing extraction for 6 h. The best methods for HPLC analysis are as follows: Zorbax Eclipse plus C8 column with mobile phase A, methanol:acetonitrile:0.25 M aqueous pyridine(50:25:25, v:v:v) and mobile phase B, methanol: acetonitrile: acetone(20:60:20, v:v:v); p H of mobile phase A adjusted to 6 with acetic acid; and HPLC column temperature maintained at 40°C. The study provides an experimental basis for future investigations of past changes in primary productivity and the response of lake ecosystems to climate change and human activities on the Tibetan Plateau.  相似文献   

6.
Research interest in speciation of arsenic stems from its species dependent behavior in the environment and in living organisms. The complexity of the matrix to be analyzed and low concentrations of target arsenic species that may be labile or difficult to chromatogram, indicate that a suitable pre‐treatment methodology is required. This study investigated the usefulness of chelation solvent extraction – high performance liquid chromatography (CSE‐HPLC) for the speciation of arsenic in water. It involved reacting arsenic with the chelant known for its affinity towards arsenic, followed by extraction, separation, and identification of the arsenic‐chelant‐arsenic complex. Arsenic species having different physicochemical properties were investigated. Species, such as, As2O3, As3O5, KH2AsO4, Na2HAsO4, and NaAsO2 were detected as a group of closely eluted peaks with different retention times and spectral properties, whereas, the organic arsenic species CH3Na2AsO3, o‐arsanilic acid, roxarson and triphenyl arsine separated quite well on the EnviroseP‐CM HPLC column. Key method parameters, such as, type of HPLC column, composition of mobile phase and organic solvents affecting peak resolution and sensitivity were optimized. Real environmental matrices contaminated with arsenic were analyzed under varying wavelengths (λmax = 190, 210, 220, 234, 244, and 282 nm), with good precision. Different arsenic species were detected in these samples with excellent background and signal‐to‐noise ratios demonstrating the robustness of the method. The detection limit, reproducibility, selectivity, accuracy, and dynamic range of the calibration curves were evaluated.  相似文献   

7.
A highly sensitive and specific enzyme immunoassay (EIA) is described for the detection of the atrazine metabolite hydroxyatrazine. Polyclonal antibodies were raised in rabbits by immunization with a hapten-bovine serum albumin (BSA) conjugate containing 8 hapten residues per molecule of BSA. An EIA with a horseradish peroxidase (HRP) hapten tracer was optimized in microtitre plates. A concentration of 50% B/B0 was found at 0.10 μg/L for hydroxyatrazine. A limit of determination for hydroxyatrazine was reached at approximately 0.01 μg/L, i.e. well below the maximum concentration permitted by the EU guidelines for drinking water and the drinking water ordinance of the FRG. The assay did not require concentration or clean-up steps for drinking water or ground water samples. Validation experiments confirmed a good accuracy and precision. Hydroxyatrazine is reported to be the main atrazine metabolite found in soil samples. As organic solvents are usually employed for soil extraction, the influence of methanol as representative organic solvent on the assay was examined. Up to a concentration of 5% (v/v) methanol, the organic solvent did not affect the assay.  相似文献   

8.
Dispersive liquid–liquid microextraction based on solidification of floating organic droplet (DLLME‐SFO) technique was successfully applied for simultaneous assay of eight polychlorinated biphenyls, two organochlorine, and four pyrethroid pesticides multi‐residue in aqueous samples by using GC‐electron capture detection. The effects of various parameters such as kind of extractant and dispersant and volume of them, extraction time, effect of salt addition, and pH were optimized. As a result, 5.0 µL 1‐dodecanol was chosen as extraction solvent, 600 µL methanol were used as dispersive solvent without salt addition, pH was adjusted to 7. Under the optimized conditions, the limits of detection (LOD) were ranged from 1.4 to 8.3 ng L?1. Satisfactory linear range was observed from 5.0 to 2000 ng L?1 with correlation coefficient better than 0.9909. Good precisions were also acquired with RSD better than 13.6% for all target analytes. The enrichment factors of the method were ranged from 786 to 1427. The method can be successfully applied to simultaneous separation and determination of three class residues in real water samples and good recoveries were obtained ranging from 76 to 130, 73 to 129, and 78 to 130% for tap water, lake water, and industrial waste water, respectively.  相似文献   

9.
As a result of discontinuous water flow, agriculture, and increasing urban use of fresh water affecting the natural wetlands of the Yellow River Delta, these areas have experienced significant degradation in the past two decades, ultimately diminishing the overall natural wetland land area in the region. This study aimed to address the issue of decreasing fresh water in the Yellow River Delta by studying the effects of three different approaches to restoration on long‐term wetland recovery. The results of the study demonstrated that soil salt and available Na contents significantly decreased in response to all three restoration treatments. Impacts of the restoration treatments were more significant in 2009 than in 2010, as shown by the high rate of activity in the reed debris group. The highest phosphatase activity of the experimental period was also observed in the reed debris group. Meanwhile, a marked variation in soil nutrient elements (total carbon (TC), total nitrogen (TN), available phosphorus, and available potassium) was observed in the restoration treatment plots throughout the experimental period. TC and TN contents were generally higher in the restoration treatment groups than in the control group. Moreover, urease and phosphatase activity levels were highly correlated with one another, as well as with soil nutrient elements. In 2009, the yield of the Suaeda salsa plant was highest in the reed debris treatment group and lowest in the ploughing treatment group. The S. salsa plant did show a positive response to all of the different restoration treatments. Taken together, these results suggest that restoration approaches that implement ploughing techniques aided in the restoration of degraded saline wetlands.  相似文献   

10.
A novel, simple method based on magnetic separation was developed for analytical purposes. In this method, N‐methyl‐D‐glucamine (NMDG) modified magnetic microparticles that were synthesized by using the sol‐gel method were used for the selective extraction and preconcentration of boron from aqueous solutions. This method combines the simplicity and selectivity of solvent extraction with the easy separation of magnetic microparticles from a solution with a magnet without any preliminary filtration step. The structure of the prepared γ‐Fe2O3‐SiO2‐NMDG (magnetic sorbent) composites were characterized by using X‐ray diffraction (XRD), Transmission Electron Microscopy (TEM), and Fourier Transform Infrared Spectroscopy (FTIR). The influence of different parameters on the sorbent capacity, such as the sorption/desorption of boron, magnetic sorbent dosage, pH, equilibrium time, type, and amount of stripping solution, were evaluated by using the magnetic sorbent. Any equilibrium pH greater than 6 can be used for sorption. Desorption from the sorbent was carried out by using 1.0 M HCl. The sorption and desorption efficiency of the γ‐Fe2O3‐SiO2‐NMDG was found as 92.5 ± 0.5% and 99.8 ± 6%, respectively.  相似文献   

11.
《Marine pollution bulletin》2009,58(6-12):275-279
Nuclear magnetic resonance spectroscopy (NMR) has been employed over many years for the elucidation of chemical structures. However, in more recent years it has been used to characterize sublethal actions of pollutants in aquatic organisms. For instance, in vivo NMR involves live, intact organisms or cell cultures and the application of chemical stressors to reveal toxic mechanisms in real time. Alternatively, NMR-based metabolomics involves rapid cessation of metabolic activity following chemical exposure (via liquid N2) to provide an assessment of metabolic actions via more traditional NMR analysis. Two examples are briefly presented to exemplify the power of NMR for assessing toxic actions in marine and freshwater organisms.  相似文献   

12.
Post‐wildfire runoff was investigated by combining field measurements and modelling of infiltration into fire‐affected soils to predict time‐to‐start of runoff and peak runoff rate at the plot scale (1 m2). Time series of soil‐water content, rainfall and runoff were measured on a hillslope burned by the 2010 Fourmile Canyon Fire west of Boulder, Colorado during cyclonic and convective rainstorms in the spring and summer of 2011. Some of the field measurements and measured soil physical properties were used to calibrate a one‐dimensional post‐wildfire numerical model, which was then used as a ‘virtual instrument’ to provide estimates of the saturated hydraulic conductivity and high‐resolution (1 mm) estimates of the soil‐water profile and water fluxes within the unsaturated zone. Field and model estimates of the wetting‐front depth indicated that post‐wildfire infiltration was on average confined to shallow depths less than 30 mm. Model estimates of the effective saturated hydraulic conductivity, Ks, near the soil surface ranged from 0.1 to 5.2 mm h?1. Because of the relatively small values of Ks, the time‐to‐start of runoff (measured from the start of rainfall), tp, was found to depend only on the initial soil‐water saturation deficit (predicted by the model) and a measured characteristic of the rainfall profile (referred to as the average rainfall acceleration, equal to the initial rate of change in rainfall intensity). An analytical model was developed from the combined results and explained 92–97% of the variance of tp, and the numerical infiltration model explained 74–91% of the variance of the peak runoff rates. These results are from one burned site, but they strongly suggest that tp in fire‐affected soils (which often have low values of Ks) is probably controlled more by the storm profile and the initial soil‐water saturation deficit than by soil hydraulic properties. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.  相似文献   

13.
Some of the pesticides listed in the European 76/464/EC Directive and in the Directive 2000/60/EC are very polar and require special analytical methodology with respect to their extraction from water. The extraction of the organophosphorus pesticides methamidophos, omethoate, oxydemeton‐methyl, mevinphos and trichlorfon with lg POW below 1 was investigated using 21 different solid‐phase materials. Each material was tested on spiked natural water at 4 different pH values, adjusted prior to extraction. The following range of materials were tested: octadecyl silica, polymers, modified silica, ion exchange and carbon. Extraction of the above compounds from water is possible. A relationship between the octanol‐water partition coefficient and recovery rates was obtained not only for octadecyl solid phases but also for some polymeric materials. General conclusions about the use of solid‐phase materials and specific conclusions about the extraction of particular compounds were made. An optimized extraction procedure was deduced and confirmed.  相似文献   

14.
Fracture aperture is an important transport property in subsurface hydrology because it influences well productivity and the volume of the water resource. Nuclear magnetic resonance (NMR) well logging measures the hydrogen‐bearing fluid molecules in porous or fractured strata, and the NMR signal intensity increases with the amount of fluid in the sensed region of the NMR sonde. Fluid confined in a large fracture of >>0.2 mm in aperture has T2 (i.e. spin‐spin relaxation time) values as long as those of the bulk fluid. The bulk‐fluid porosity (i.e. porosity calculated using this long T2 component in a T2 histogram data) increases linearly with aperture. Therefore, NMR logging enables quantitative estimation of fracture apertures of >>0.2 mm using the bulk‐fluid porosity data if the calibration of the NMR sonde is performed adequately. We applied NMR logging to a borehole in a Holocene andesite lava at Sumikawa, Japan, to estimate the aperture of open fractures within the lava. A test well of 100 m depth and 20 cm diameter, filled with bentonite drilling mud, was scanned with an NMR sonde to obtain a profile of the porosity and the T2 histogram of the andesite. The bulk‐fluid porosity was calculated from the T2 histogram data, as the porosity at which the T2 value is larger than or equal to a threshold T2 of bulk bentonite mud. The bulk‐fluid porosity of a specific inclined fracture responsible for the total loss of circulation at 61.2 m depth during drilling was calculated assuming a threshold or T2 cut‐off of 33 ms, and again for a cut‐off of 100 ms. Calibration of the NMR sensor in a laboratory and measurement of the fracture dip angle by electrical microimaging logging enabled us to estimate the fracture aperture as 1.7 cm, assuming a T2 cut‐off of 33 ms, or 1.6 cm for a T2 cut‐off of 100 ms. The method of aperture determination described in this study is independent of fluid species and lithology, and is applicable to various hydrogen‐bearing borehole fluids (clean water, mud and oil) and geological settings.  相似文献   

15.
Cadmium (Cd) has become an important heavy metal contaminant in the sediment and seawater along the Bohai Sea and been of great ecological risk due to its toxic effects to marine organisms. In this work, the toxicological effects caused by environmentally relevant concentrations (10 and 40 µg L?1) of Cd were studied in the gill tissues of Manila clam Ruditapes philippinarum after exposure for 24, 48, and 96 h. Both low (10 µg L?1) and high (40 µg L?1) doses of Cd caused the disturbances in energy metabolism and osmotic regulation and neurotoxicity based on the metabolic biomarkers such as succinate, alanine, branched chain amino acids, betaine, hypotaurine, and glutamate in clam gills after 24 h of exposure. However, the recovery of toxicological effects of Cd after exposure for 96 h was obviously observed in clam to Cd exposures. Overall, these results indicated that NMR‐based metabolomics was applicable to elucidate the toxicological effects of heavy metal contaminants in the marine bioindicator.  相似文献   

16.
Hydrological connectivity inside the soil is related to the spatial patterns inside the soil (i.e., the structural connectivity). This, in turn, is directly associated with the physical and the chemical processes at a molecular level (i.e., the functional connectivity). Nuclear magnetic resonance (NMR) relaxometry can be successfully applied to reveal both structural and functional components of soil hydrological connectivity. In the present study, the low field NMR relaxometry was applied on water suspended soils sampled at the upstream‐ and downstream‐end of three different length plots. Also the sediments collected from the storage tanks at the end of each plot were water suspended and monitored by NMR relaxometry. The results from the NMR investigations were elaborated by using a mathematical approach in order to quantify both the functional and structural connectivity components. In particular, following integration of the T1 distribution curve, an S‐shaped curve was obtained. It revealed two plateaus corresponding to the shortest (low component) and the longest (high component) intervals of relaxation times, respectively. According to relaxometry theory, the two T1 intervals, associated to the different plateaus, were attributed to micro and macro soil pores, respectively. The two T1 intervals were used to define a functional connectivity index, while the central part of the S‐shaped distribution was used to define a structural connectivity index. Here we provide the physical meaning of the our mathematical approach, thereby revealing that functional connectivity index increases with plot length, as a result of a selective eroded particle transport. Moreover, the relationship structural connectivity index versus plot length resulted quasi‐independent of grainsize distribution, whereas the values of the structural connectivity index for the sediment samples resulted lower than those obtained for the corresponding soils.  相似文献   

17.
A field tracer test was carried out in a light nonaqueous phase liquid (LNAPL) source zone using a well pattern consisting of one injection well surrounded by four extraction wells (5‐spot well pattern). Multilevel sampling was carried out in two observation wells located inside the test cell characterized by heterogeneous lithology. Tracer breakthrough curves showed relatively uniform flow within soil layers. A numerical flow and solute transport model was calibrated on hydraulic heads and tracer breakthrough curves. The model was used to estimate an average accessible porosity of 0.115 for the swept zone and an average longitudinal dispersivity of 0.55 m. The model was further used to optimize the relative effects of viscous forces versus capillary forces under realistic imposed hydraulic gradients and to establish optimal surfactant solution properties. Maximum capillary number (NCa) values between injection and extraction wells were obtained for an injection flow rate of 16 L/min, a total extraction flow rate of 20 L/min, and a surfactant solution with a viscosity of 0.005 Pa?s. The unconfined nature of the aquifer limited further flow rate or viscosity increases that would have led to unrealistic hydraulic gradients. An NCa range of 3.8 × 10?4 to 7.6 × 10?3 was obtained depending on the magnitude of the simulated LNAPL‐water interfacial tension reduction. Finally, surfactant and chase water slug sizing was optimized with a radial form of the simplified Ogata‐Banks analytical solution (Ogata and Banks 1961) so that injected concentrations could be maintained in the entire 5‐spot cell.  相似文献   

18.
In this study, a new solid‐phase extraction procedure has been developed for preconcentration and determination of Co ions in different water samples by flame atomic absorption spectrometry (FAAS). Cobalt was preconcentrated as N,N′‐bis(pyridine‐2‐yl‐methyl)benzene‐1,4‐diamine (Co‐BPMBDA) from sample solutions using a column containing Amberlite XAD‐7 and was determined. In order to achieve the best performance for the method, effects of several parameters such as pH, concentrations of ligand, sample flow rate, eluent, and matrix ions on the method efficiency were investigated. Under optimum conditions, the preconcentration factor was found to be 200 for 1000 mL waters samples. Detection limit based on the 3Sb criterion was calculated as 0.24 µg/L for 100 mL of sample solution and relative standard deviation was found to be 1.8%. The method was applied to determine the trace amounts of cobalt in water samples.  相似文献   

19.
In this study, a field experiment was conducted to investigate the soil water dynamics and water percolation through the deep vadose zone. A calibrated HYDRUS‐1D model was used to simulate the process of soil water movement and the water budget. Based on the measured volumetric soil water contents, the model was well calibrated and validated. Then, we conducted scenario analyses to determine the combined effects of irrigation amount (IA), antecedent soil moisture (AM), crop evapotranspiration, and deep percolation (DP) in an irrigation event. Four IAs (5, 10, 15, and 20 cm) and three AM conditions (AM‐1, AM‐2, and AM‐3) were controlled in the scenario analyses. The results indicate that according to the Se's (effective saturation) values status and the observed or simulated depth, there could be different conclusions on the influence of DP. Under different IAs in dry (AM‐1) and medium (AM‐2) AM status, DP changed slightly; it was 0.39 and 2.47 cm in AM‐1 and 0.40 and 2.48 cm in AM‐2 for the summer maize and winter wheat crop, respectively; the AM had a crucial contribution to DP. While under the condition of wet AM (AM‐3) or small observation depth, the water inputs could have a significant effect on DP. According to increasing irrigation intensity, the higher values of Se (>0.6) in the whole profile were only displayed between 70 and 300 cm at AM‐1, 70–500 cm at AM‐2, and 70‐below 600 cm at AM‐3, which were gradually extended and moved down with increasing AM. Hence, the IA significantly affected the water percolation at a depth of 200 cm, whereas there was a weak influence at 600 cm except in AM‐3. Furthermore, in the higher values of the Se (>0.65) domain, the correlation between IA and DP was an exponential function and significantly under P < 0.05. In addition, DP began to occur when the soil water content was equal to or greater than 0.75 times that of the field water capacity or the Se > 0.65. When the coarse silt layer became embedded in the silt clay soil profile, it lagged the process of water transport but did not affect permeability in the end.  相似文献   

20.
The objective of this paper is to simulate the progress of the soil water content distribution in the soil profile with a water table at the bottom of the soil profile during ponding irrigation. This simulation can be done by solving the two‐dimensional Richards's equation for the assimilation of the advancing water jet, which uses the conditions of the two exponential functional forms k = ks eαψ and θ = θr + (θs − θr) eαψ to represent the hydraulic conductivity and volumetric water content, with ψ the pressure as the third variable. We assume that the ground surface becomes ponded and saturated as soon as the water flux passes the dry ground surface. By the technique of transformation, the analytical solution of these two‐dimensional Richards' equations has enabled figures of volumetric water content distribution to be obtained in successive time periods after irrigation. For the example of loam soil, it can simulate the variation of volumetric water content during and after irrigation in the soil profile. The analytical solutions of this paper reflect the real situation simulated, and can be applied to verify those complicated solutions from other analytical models. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

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