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A class of KdV-Burgers equations with large Reynolds numbers and weak dispersions were discussed, which were mathematically expressed as a class of singularly perturbed KdV-Burgers equations. The interaction between the nonlinear term and the dispersion term in the KdV-Burgers equation forms a stable forward-propagation soliton. Through mathematical analysis, the propagation path and speed of the soliton were described. By means of the singularly perturbed expansion method, the asymptotic solution to the problem was constructed. First, the degenerate solution was obtained with the Riemann-Earnshaw method, and the simple wave was obtained. There is a velocity difference between any point of the simple wave shape and the initial point, which makes the wave form continuously distorted in the process of propagation, and finally forms the shock wave surface, namely discontinuity. There is a time-varying jump in the velocity of particles between both sides of the discontinuity. Second, a modified traveling wave transformation was built through substitution of variables at the discontinuity of the degenerate solution, to obtain soliton solutions of the expansion of internal solutions and prove the existence and uniqueness of the internal and external solutions. Finally, the residual term was estimated with the existence of the uniformly bounded inverse operator, and the uniform effectiveness of the asymptotic solution was obtained. The results show that, the perturbations of KdV-Burgers equations with large Reynolds numbers and weak dispersions concentrate on the neighbourhoods of the discontinuities of the degenerate solutions. The soliton links the particles across the 2 sides, and its propagation path is not a linear form of time and space, but leads along the discontinuity of the degenerate solution, forming a stable waveform. [ABSTRACT FROM AUTHOR]

The wave model generated for laser plasma was discussed, which can be expressed as the Riemann problem of Burgers equations with initial value discontinuity. The singularly perturbed asymptotic solution of the Burgers equations with discontinuous initial values was obtained with the singularly perturbed expansion method. The solution was divided into 2 parts: an outer solution and an inner layer correction term. Since the initial condition is constant, the wave will generate the characteristic boundary in the process of propagation, and the correction term will make the parabolic characteristic boundary. The external solution was corrected at the internal layer along the characteristic lines. The existence and uniqueness of the asymptotic solution was proved through the HopfCole transform, Fourier transform and the extremum principle. Then the asymptotic expansion is obtained with the uniform validity proved. [ABSTRACT FROM AUTHOR]

In order to determine the release characteristics of phosphorus in Dianchi Lake, Yunnan, China under suitable conditions and evaluate its effects on algae in the presence of exogenous phosphorus, an outdoor simulation method was used to study the characteristics of phosphorus in the sediment and overlying water of Dianchi Lake and to explore the effects of phosphorus release from sediments on algae. The results showed that the phosphorus content（total phosphorus, dissolved phosphorus, and orthophosphate）in the lower layer of the over-lying water was higher than that of the upper layer. Phosphorus was mainly present in the sediment as calcium-bound phosphorus and organic phosphorus. The most important contributions to phosphorus content in water were from iron-aluminum-bound phosphorus and organic phosphorus. There was a positive correlation between orthophosphate and chlorophyll content in water. The increase in orthophosphate content significantly aggravated the eutrophication of water. The exchangeable phosphorus content in the sediment was significantly positively correlated with chlorophyll in water. The release of phosphorus from the sediment was the most important endogenous load for algae growth. Therefore, controlling the concentration of iron-aluminum-bound phosphorus in orthophosphates and in sediment in water bodies, as well as limiting the conversion and mineralization of organic phosphorus, could be an effective control measure. [ABSTRACT FROM AUTHOR]

A temperature field model for single-layer materials was constructed with the non-Fourier heat conduction law, i.e. a type of singularly perturbed hyperbolic equations with small parameters in an unbounded domain. The asymptotic solution to the problem was obtained with the singularly perturbed expansion method. Firstly, the singular perturbation method was used to obtain the external solution and boundary layer correction terms of the problem. Through estimation of the maximum norms of the internal solution and the external solution, and the maximum norms of the time derivative, and under the theory of linear parabolic equations, the existence and uniqueness of the internal and external solutions were obtained, and the formal asymptotic expansion of the solution was obtained. The L2 estimator of the asymptotic solution was given with the remainder estimator. The uniform validity of the asymptotic solution and the distribution of the temperature field in the unbounded domain were got. Through singular perturbation analysis, the relationship between the non-Fourier temperature field and the Fourier temperature field was given, and the specific behaviors of the non-Fourier temperature field were described. [ABSTRACT FROM AUTHOR]

In order to study the effect of different types and particle size of passivators on the repair of heavy metal pollution in soils, three particle sizes（60~100, 100~200, >200 mesh）with four different passivating agents（self-made inorganic passivating agent, lime+biochar, diatomaceous earth, phosphate rock powder）were added through laboratory cultivation experiments to study the effect of the type and size of passivation agents on the effective Cd and Pb in heavy metal complex contaminated soil. The results after 60 days passivation showed that self-made inorganic passivation agent, biochar+lime and phosphate rock powder had the best passivation effect on soil available Cd at >200 mesh particle size, which reduced by 9.54%, 13.93% and 11.08%, respectively, compared with the control; Diatomite had the best effect at a particle size of 100~200 mesh, and the effective Cd content reduced by 22.35% compared with the control. The passivation effect of self-made inorganic passivation agent, lime+biochar, diatomaceous earth and phosphate rock powder on soil available Pb is best under the particle size of >200 mesh, which reduced by 17.81%, 18.7%, 11.54% and 22.19%, compared with the control, the phosphate rock pow- der passivation had the best passivation effect. It indicated that the self-made inorganic passivation agent, lime+biochar and phosphate rock powder had the better effect of Cd and Pb on the passivated soil heavy metals at the smaller particle size. There is not significantly different among the three particle size treatments of diatomaceous earth. [ABSTRACT FROM AUTHOR]

Using Gleeble 3500，the deformation behaviors of a single-pass compression for Fe-6.5%Si steel at temperature ranging from 300 to 600°C and strain rate ranging from 0.05 to 5s-1 were studied. The flowstress increases dramatically at initial uniform plastic deformation stage due to work hardening， while the increment of flow stress is to be weakened during further deformation when the dynamic softening occurs. The strain hardening index decreases with increasing the temperature and decreasing the strain rate. A new constitutive model of Fe-6.5%Si steel at moderate-temperature deformation was proposed through describing the strain hardening index as the function of temperature and strain rate. The results predicted by this model are in good agreement with the experimental data， with an average relative error about 5.35%. [ABSTRACT FROM AUTHOR]

The singular perturbation solutions to a class of bounded stochastic Burgers equations under colored noises were discussed, of which the volatility followed the weak noise Orn-stein-Uhlenbeck (O-U) process. With the Kolmogorov equation satisfied by the probability density function of wave motion, the Kolmogorov equation satisfied by the expectation of the random Burgers equation was obtained. Since the initial boundary conditions for the Kolmogorov e-quation relate to a class of deterministic solutions to the Burgers equation, this problem is actually a simultaneous form of the Burgers equation and the Kolmogorov equation. Firstly, the regular asymptotic expansion of a class of deterministic Burgers equations was given. Based on the Schauder estimates and the Ascoli-Arzela theorem, boundedness and existence of the asymptotic solutions to the nonlinear parabolic equations were proved; moreover, according to the Lax-Milgram theorem, boundedness and existence of the asymptotic solutions to the linear parabolic equations were proved. The formal asymptotic solution of wave expectation was obtained. Secondly, with the singular perturbation theory, the asymptotic expansion of singular perturbation and the boundary layer correction of a class of expected equations were got. The existence and boundedness of the asymptotic solutions to the boundary layer functions were obtained according to the theory of linear partial differential equations. By means of the extremum principle and the De-Giorgi iterative techniques, the boundedness of the remainder terms of the asymtotic solutions of wave velocity and wave expectation was proved respectively, and the uniformly valid estimate for the asymptotic solution of the system was obtained. [ABSTRACT FROM AUTHOR]

It has been paid much attention to soil heavy metal pollution in the Bijiang watershed caused by the Lanping lead-zinc mine. We collected 35 arable soil samples along Bijiang, then sampled and tested the contents of As, Cu. Zn. Cd, Pb, Hg. And then with Nemerow Multi-Factor Index and the Potential Ecological Risk Index method, we evaluated the heavy metal pollution risk. The results showed; (1)The accumulation of Pb, Zn, Cd was in a relatively high level, the average was 1 146.97, 579.15, 4.85 mg·kg-1 respectively, which was seriously polluted; the average accumulation of As was 26.85 mg·kg-1; but Cu, Hg was slightly polluted. (2) Statistical analysis showed that Lanping area was a main point source pollution of As, Zn. Pb, Cd, while Cu, Hg was pollution caused by different non-point source pollution. (3) Within this basin, the JNemerow index was 17.69, which was serious heavy metal pollution, while the comprehensive potential ecological risk index was 773.38, which was a strong potential ecological risk. Hie contribution of pollutants was Cd>Pb>Zn>As>Hg>Cu. (4)As a whole, the soil heavy metal pollution of paddy field was higher than of the dry land. [ABSTRACT FROM AUTHOR]

The simulation experiment of three types soil phosphorous, respectively activated by the zeolite, the high temperature modified am monium saturated zeolite, the ammonium saturated zeolite, and the high temperature modified zeolite was conducted to determine the incre ment of soil available phosphorus in 0 - 10, 10 - 20, 20 - 30, 30 - 40 d, respectively, and studied the ability of different phosphate-dissolving way activating immobilized phosphorus in soil. The result showed that the unification of the zeolite and saturated NH/ unify could in crease the exchange quantity of zeolite cations, obviously enhanced the phosphate-dissolving quantity of zeolite; the organic matter adsorbing in the zeolite crevice might be removed by the high temperature modified way, thus increased the adsorptive capacity and the loading capacity of the zeolite, enhanced the phosphate-dissolving quantity of zeolite. Effect about the zeolite without processing was not obvious. In 4 time sections, the high temperature modified ammonium saturated zeolite and the ammonium saturated zeolite could dissolve the most phosphorus in 0 - 10 d with different soil types; the phosphate-dissolving quantity of the high temperatu remodified zeolite and the zeolite in 0 - 10d were smallest; the phosphate-dissolving efficiency of the four kinds of zeolite was the high temperature modified ammonium saturated zeolite > the ammonium saturated zeolite > the high temperature modified zeolite > the zeolite. There was big difference of phosphorus element activated rate between different soil types with matched quantity of phosphorus, which mostly related to total phosphorus content and available phosphorus content in the soil. The lower the total phosphorus content, the higher the phosphorus element activation rate was; the lower the avail able phosphorus content, the lower the phosphorus element activation rate was. [ABSTRACT FROM AUTHOR]

The soil type in China are rich and diverse, and the occurrence forms of heavy metals in different regions are different. It is difficult to compare and evaluate the effectiveness of heavy metals in different regions and different types of soils. In order to screen and establish a method for evaluating the effectiveness of heavy metals in farmland soils in suitable areas, five typical farmland soils (yellow brown soil, yellow soil, red soil, lime soil and purple soil) with different properties in eastern Yunnan were selected. The extraction conditions (solid-liquid ratio, extractant pH value and oscillation time) of ABDTPA method were orthogonally combined by orthogonal test, the soil-crop Pb migration model was established to compare the goodness of fit with the total method, CaCl2 -DTPA method and AB-DTPA method. Pot experiments were carried out with Chinese cabbage and spinach as indicator plants to explore the correlation between different analysis methods and plant Pb accumulation ability, and then comprehensively evaluate the suitability of different methods.The results showed that the solidliquid ratio (g/mL) 1:3, pH 7.6 and shaking time 120 min had a great influence on the extraction amount of Pb; The optimized AB-DTPA method (solid-liquid ratio (g/mL) 1:3, pH 7.6, and oscillation time of 120 min) obtained through orthogonal experimental screening has the best effect on predicting the effective state extraction amount of Pb and the amount of Pb absorbed by crops, which can better predict the crop's ability to absorb Pb; The pot experiment showed that the available Pb content extracted by the optimized AB-DTPA method had a better correlation with the Pb content absorbed by Chinese cabbage and spinach ( R² = 0.898, R² = 0.752 ), with a Pb spiked recovery rate range of 99.5%-113.0% and high accuracy. Therefore, the optimized AB-DTPA method (Solid-liquid ratio 1:3, pH 7.6 and shaking time 120 min) is suitable for the extraction of Pb available state in Yunnan farmland soil. The method is feasible, universal and accurate. The research results provide a basis for the effect of regional farmland soil remediation technology and pollution risk assessment. [ABSTRACT FROM AUTHOR]

【Objective】Whether the effect of exogenous microorganism was stable was a great significance to biological composting. The present paper aimed to obtain compound microbial inoculum with better environmental tolerance and enhance the competitiveness and effect of the microorganism bacteria in biological composting.【Method】25 groups of compound microbes were constructed from 20 strains with cellulose decomposing ability isolated from the natural environment in the previous research work. 21 groups of compound microbes were screened out through the antagonistic relationship test, and the cellulase activities of 21 groups were determined by the method of liquid fermentation and DNS, which included filter paper enzyme activity(FPase) and carboxymethyl cellulose sodium enzyme activity(CMCase) under different temperature conditions(35, 45 and 55 ℃) and different acid and alkali conditions(pH value 6, 7.5 and 10). 【Result】Finally, CM17 with wide temperature adaptability and acid-base adaptability was screened out, and the compound bacteria could decompose cellulose normally within the temperature from 35 to 55 ℃ and the pH value 6 to 10. 16 SrDNA molecular identification showed that the 4 strains of CM17 were Alternaria alternate, Streptomyces sp., Oerskovia sp. and Aureobasidium sp.. CM17 had better cellulase activity than single strain, and when the ratio of 4 bacteria was 1∶1∶1∶1, the compound had the best cellulolytic enzyme activity. 【Conclusion】CM17 was stable and had better environmental tolerance. This study had certain theoretical and applied value for biological composting in complex environment. [ABSTRACT FROM AUTHOR]

该文回顾性分析该院收治的1例肺肉瘤样癌(PSC)伴胸椎、空肠转移患者的临床诊断过程。患者入院完善胸腹 增强CT:左肺下叶肿瘤病变,肺癌可能,双肺多个转移结节,纵隔淋巴结考虑转移,空肠套叠,肿瘤病变可能,近端小肠梗阻。术中 发现空肠肿物致空肠套叠,近端空肠梗阻扩张,行空肠肿物切除+端侧吻合术,术后病理确诊小肠肉瘤样癌。结合病情发展、增强 CT影像特征及空肠病理结果的分析,临床诊断为PSC伴空肠转移。 [ABSTRACT FROM AUTHOR]