The effects of soil water regime and soil reaction on nitrogen distribution and fractional composition of newly-formed humus (decayed products) and the structural characteristics of the newly-formed humic acids (HAs) ...The effects of soil water regime and soil reaction on nitrogen distribution and fractional composition of newly-formed humus (decayed products) and the structural characteristics of the newly-formed humic acids (HAs) were studied in an incubation experiment, with the following results obtained:1. The humus newly formed under submerged conditions was higher in the relative content of α-amino acid-N and the humic acid/ fulvic acid (HA/ FA) ratio than that under upland conditions. The HAs extracted from the former were also higher in C / O ratio, aromaticity and the contents of methoxyl groups and lignin-like components, but lower in the content of carboxyl groups than the HAs from the latter.2. Under upland conditions, the C / organic N ratio and the relative content of mobile HA of newly-formed humus were lower, but the HA / FA ratio was higher in the CaCO3-amended treatment than in non-amended treatment. The presence of CaCO3 also resulted in a decrease of C / N ratio of HA and a slight increase of its carboxyl group content. On the other hand, there was no significant change in the composition and properties of the newly-formed humus with the addition of CaCO3 under submerged conditions.3. Compared with soil HAs, the newly-formed HAs contained more carbohydrates, polypeptides and lignin-like components, and were in lower degrees of oxidation and humification.展开更多
Heavy metal concentrations in soils may decrease over time,correlating with key soil variables such as pH,cation exchange capacity(CEC),clay,and organic carbon(organic C)content.The residual Cu and Zn were studied in ...Heavy metal concentrations in soils may decrease over time,correlating with key soil variables such as pH,cation exchange capacity(CEC),clay,and organic carbon(organic C)content.The residual Cu and Zn were studied in tropical soils about 20 years after amendment with heavy metal containing industrial waste.Soils amended one time in 1998 with industrial waste,calcite,and cassava-leaf compost were employed as models and analysed for topsoil and subsoil Cu,Zn and several soil properties including pH,CEC,clay and organic C content in 2018.The highest Cu and Zn were detected in high heavy metal plots with the highest waste amendment,lowered by calcite and/or compost.The lower subsoil Cu and Zn were strongly affected by topsoil Cu and Zn.Single variable linear regression showed that the soil Cu and Zn had good relationships with the soil organic C and clay content.The inclusion of soil pH,CEC,clay and organic C content in multiple linear regression analysis improved their correlation coefficients,in which the correlation coefficients of Zn were higher than Cu.Long-term reaction in soils reversed the positive correlation of Cu-pH and Zn-pH in 1998 to the negative correlations in 2018.The soil Cu can be predicted with 33.8%accuracy with equation Cu=-61-11.6(pH)+0.47(CEC)+2.71(Clay)+41.7(Org C)(R^(2))=-0.338 while the soil Zn with accuracy 39.2%by equation Zn=-26.2-8.73(pH)-0.276(CEC)+1.95(Clay)+24.0(Org C)(R2).This results could be utilized to monitor the dynamic of Cu and Zn contamination in soil.展开更多
This paper conducts laboratory tests to investigate detailedly the soil deformation law around the pipeline and its penetration depth under self-gravity. The seabed model is prepared by consolidating saturated soil us...This paper conducts laboratory tests to investigate detailedly the soil deformation law around the pipeline and its penetration depth under self-gravity. The seabed model is prepared by consolidating saturated soil using vacuum pressure technology, and the pipeline models are specifically designed to possess different radii. Based on the experimental results and digital images, the soil deformation process is analyzed and summarized, a kinematic admissible velocity field is given and an upper bound solution of pipeline penetration depth and soil reaction force is derived and proposed in this paper. In order to verify the accuracy of the upper bound solution deduced in this paper,a comparison is made among some published results and the solution suggested in this paper, the comparison results confirm that the upper bound solution and the soil failure mode are reasonable. Finally two empirical formulas are given in this paper to estimate the soil reaction force of seabed and the penetration depth of pipeline. The empirical formulas are in agreement with the upper bound solution derived in this paper, and the conclusion of this paper could provide some theoretical reference for the further study of the interaction between the pipeline and the soil.展开更多
Heterogeneous reactions of nitrogen dioxide （NO2） on soils collected from Dalian （S 1） and Changsha （S2） were investigated over the relative humidity （RH） range of 5%-80% and temperature range of 278-328 K usi...Heterogeneous reactions of nitrogen dioxide （NO2） on soils collected from Dalian （S 1） and Changsha （S2） were investigated over the relative humidity （RH） range of 5%-80% and temperature range of 278-328 K using a horizontal coated-wall flow tube. The initial uptake coefficients of NO2 on S2 exhibited a decreasing trend from （10 ± 1.3） × 10-8 to （3.1 ± 0.5） x 10-8 with the relative humidity increasing from 5% to 80%. In the temperature effect studies, the initial uptake coefficients of S1 and S2 decreased from （10± 1.2） × 10-8 to （3.8 ± 0.5） × 10-8 and from （16± 2.2） × 10-8 to （3.8 ±0.4） × 10-8 when temperature increased from 278 to 288 K for S1 and from 278 to 308 K for S2, respectively. As the temperature continued to increase, the initial uptake coefficients of S1 and S2 returned to （7.9 ± 1.1）× 10-8 and （20 ± 3.1） × 10-8 at 313 and 328 K, respectively. This study shows that relative humidity could influence the uptake kinetics of NO2 on soil and temperature would impact the heterogeneous chemistry of NO2.展开更多
Factors including Mg^2＋, dNTP and primer that affected RAPD were studied using orthogonal experimental design, and at the same time, anneal temperature, extending time and cycles were also studied. Finally, PCR react...Factors including Mg^2＋, dNTP and primer that affected RAPD were studied using orthogonal experimental design, and at the same time, anneal temperature, extending time and cycles were also studied. Finally, PCR reaction system that is feasible for black soil microbial PCR amplification was determined, containing 7 ng DNA template, 20 pM random primers, 1.5 U Taq DNA polymerase, 3.0 mM MgCl2 and 0.2 mmol ·L^-1 dNTP, with procedure： 40 cycles for 3 min at 94 ℃ （temperature）, 40 s at 37 ℃ （annealing）, 1.5 min at 72 ℃ （extension）, a final elongation step at 72 ℃ for 7 min.展开更多
In this paper, the flexural behavior of laterally loaded tapered piles in cohesive soils is investigated. The exact solution for the governing differential equation of the problem is obtained based on the beam-on-elas...In this paper, the flexural behavior of laterally loaded tapered piles in cohesive soils is investigated. The exact solution for the governing differential equation of the problem is obtained based on the beam-on-elastic foundation approach in which the soil reaction on the pile is related directly to the pile lateral deflection. In this investigation, the modulus of subgrade reactions is assumed to be constant along the pile depth. Parametric study through numerical examples is carried out to prove the validity and accuracy of the obtained results. In general, the derived displacement field can be used to study pile response in multilayered soil profiles by subdividing the pile into a number of elements. It is found that tapered piles show stiffer behavior than that for prismatic ones having the same material volume with an optimum stress distribution along the pile depth. Accordingly, tapered piles are more efficient and economic than those having the same material volume. Verification is also carried out for the obtained results through finite element analysis and the selected number of elements gives a very good agreement for lateral deflection and a larger number of elements is required to obtain better results for bending moment because of moment loss resulting from the lack of shear diagram.展开更多
The ideal reducing reagent in testing available nitrogen of soil by Conway Methodis Devard‘s alloy.The optimum ratio of soil:Devard’s alloy:1.0N NaOH solution is 5.0g:0.2g:5ml.When reaction goes on at 30℃ for 4 hou...The ideal reducing reagent in testing available nitrogen of soil by Conway Methodis Devard‘s alloy.The optimum ratio of soil:Devard’s alloy:1.0N NaOH solution is 5.0g:0.2g:5ml.When reaction goes on at 30℃ for 4 hours,the rate of soil NO<sub>3</sub>-N reduction is about 90%,and the recovery rate of soil NH<sub>4</sub>-N is about 95%.Some organic nitrogen can be measured at thesame time.This method is defined as the Modified Conway Method and the soil N-min is r=0.982（n=10）.In predicting soil nitrogen supplying power,the Modified Conway Method takesonly 1/6 of time needed by Conway Method.The Modified Conway Method can also be used forthe measure of soil N-min.展开更多
This work presents a new analytical method to analyze the influence of reaction piles on the test pile response in a static load test.In our method,the interactive effect between soil and pile is simulated using indep...This work presents a new analytical method to analyze the influence of reaction piles on the test pile response in a static load test.In our method,the interactive effect between soil and pile is simulated using independent springs and the shear displacement method is adopted to analyze the influence of reaction piles on test pile response.Moreover,the influence of the sheltering effect between reaction piles and test pile on the test pile response is taken into account.Two cases are analyzed to verify the rationality and efficiency of the present method.This method can be easily extended to a nonlinear response of an influenced test pile embedded in a multilayered soil,and the validity is also demonstrated using centrifuge model tests and a computer program presented in the literature.The present analyses indicate that the proposed method will lead to an underestimation of the test pile settlement in a static load test if the influence of the presence of reaction piles on the test pile response is neglected.展开更多
Fluorine contaminates the environment. The study of fluorine contamination profile can be made easy by the use of nuclear analytic method. Measurement of prompt gamma emitted from bombarding fluorine polluted environm...Fluorine contaminates the environment. The study of fluorine contamination profile can be made easy by the use of nuclear analytic method. Measurement of prompt gamma emitted from bombarding fluorine polluted environmental sample with proton beam from accelerator provides rapid assessment of fluorine contamination. In this paper, 340 keV proton beam induced F 19 (P,αγ) O 16 reaction is performed, measurement of prompt gamma 6130 keV gives fluorine content in the soil and leaves of plants (parasol, cotton and glossy privet), taken from the fluorine polluted area.展开更多
文摘The effects of soil water regime and soil reaction on nitrogen distribution and fractional composition of newly-formed humus (decayed products) and the structural characteristics of the newly-formed humic acids (HAs) were studied in an incubation experiment, with the following results obtained:1. The humus newly formed under submerged conditions was higher in the relative content of α-amino acid-N and the humic acid/ fulvic acid (HA/ FA) ratio than that under upland conditions. The HAs extracted from the former were also higher in C / O ratio, aromaticity and the contents of methoxyl groups and lignin-like components, but lower in the content of carboxyl groups than the HAs from the latter.2. Under upland conditions, the C / organic N ratio and the relative content of mobile HA of newly-formed humus were lower, but the HA / FA ratio was higher in the CaCO3-amended treatment than in non-amended treatment. The presence of CaCO3 also resulted in a decrease of C / N ratio of HA and a slight increase of its carboxyl group content. On the other hand, there was no significant change in the composition and properties of the newly-formed humus with the addition of CaCO3 under submerged conditions.3. Compared with soil HAs, the newly-formed HAs contained more carbohydrates, polypeptides and lignin-like components, and were in lower degrees of oxidation and humification.
基金funded by the Directorate General of Higher Education,the Ministry of National Education,the Republic of Indonesia through Competitive Research Grant in 1995-1999,in establishing the initial 1998 experimental plots.
文摘Heavy metal concentrations in soils may decrease over time,correlating with key soil variables such as pH,cation exchange capacity(CEC),clay,and organic carbon(organic C)content.The residual Cu and Zn were studied in tropical soils about 20 years after amendment with heavy metal containing industrial waste.Soils amended one time in 1998 with industrial waste,calcite,and cassava-leaf compost were employed as models and analysed for topsoil and subsoil Cu,Zn and several soil properties including pH,CEC,clay and organic C content in 2018.The highest Cu and Zn were detected in high heavy metal plots with the highest waste amendment,lowered by calcite and/or compost.The lower subsoil Cu and Zn were strongly affected by topsoil Cu and Zn.Single variable linear regression showed that the soil Cu and Zn had good relationships with the soil organic C and clay content.The inclusion of soil pH,CEC,clay and organic C content in multiple linear regression analysis improved their correlation coefficients,in which the correlation coefficients of Zn were higher than Cu.Long-term reaction in soils reversed the positive correlation of Cu-pH and Zn-pH in 1998 to the negative correlations in 2018.The soil Cu can be predicted with 33.8%accuracy with equation Cu=-61-11.6(pH)+0.47(CEC)+2.71(Clay)+41.7(Org C)(R^(2))=-0.338 while the soil Zn with accuracy 39.2%by equation Zn=-26.2-8.73(pH)-0.276(CEC)+1.95(Clay)+24.0(Org C)(R2).This results could be utilized to monitor the dynamic of Cu and Zn contamination in soil.
基金financially supported by the National Natural Science Foundation of China(Grant No.51679224)
文摘This paper conducts laboratory tests to investigate detailedly the soil deformation law around the pipeline and its penetration depth under self-gravity. The seabed model is prepared by consolidating saturated soil using vacuum pressure technology, and the pipeline models are specifically designed to possess different radii. Based on the experimental results and digital images, the soil deformation process is analyzed and summarized, a kinematic admissible velocity field is given and an upper bound solution of pipeline penetration depth and soil reaction force is derived and proposed in this paper. In order to verify the accuracy of the upper bound solution deduced in this paper,a comparison is made among some published results and the solution suggested in this paper, the comparison results confirm that the upper bound solution and the soil failure mode are reasonable. Finally two empirical formulas are given in this paper to estimate the soil reaction force of seabed and the penetration depth of pipeline. The empirical formulas are in agreement with the upper bound solution derived in this paper, and the conclusion of this paper could provide some theoretical reference for the further study of the interaction between the pipeline and the soil.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (No.KJCX2-EW-H01)the National Basic Research Program(973) of China (No. 2011CB403401)the National Natural Science Foundation of China (No. 21077109,41005070)
文摘Heterogeneous reactions of nitrogen dioxide （NO2） on soils collected from Dalian （S 1） and Changsha （S2） were investigated over the relative humidity （RH） range of 5%-80% and temperature range of 278-328 K using a horizontal coated-wall flow tube. The initial uptake coefficients of NO2 on S2 exhibited a decreasing trend from （10 ± 1.3） × 10-8 to （3.1 ± 0.5） x 10-8 with the relative humidity increasing from 5% to 80%. In the temperature effect studies, the initial uptake coefficients of S1 and S2 decreased from （10± 1.2） × 10-8 to （3.8 ± 0.5） × 10-8 and from （16± 2.2） × 10-8 to （3.8 ±0.4） × 10-8 when temperature increased from 278 to 288 K for S1 and from 278 to 308 K for S2, respectively. As the temperature continued to increase, the initial uptake coefficients of S1 and S2 returned to （7.9 ± 1.1）× 10-8 and （20 ± 3.1） × 10-8 at 313 and 328 K, respectively. This study shows that relative humidity could influence the uptake kinetics of NO2 on soil and temperature would impact the heterogeneous chemistry of NO2.
基金This Work was Supported by the National Natural Science Foundation of China (30230250, 30370819) Heilongjiang ProvinceScience Foundation (C0215)
文摘Factors including Mg^2＋, dNTP and primer that affected RAPD were studied using orthogonal experimental design, and at the same time, anneal temperature, extending time and cycles were also studied. Finally, PCR reaction system that is feasible for black soil microbial PCR amplification was determined, containing 7 ng DNA template, 20 pM random primers, 1.5 U Taq DNA polymerase, 3.0 mM MgCl2 and 0.2 mmol ·L^-1 dNTP, with procedure： 40 cycles for 3 min at 94 ℃ （temperature）, 40 s at 37 ℃ （annealing）, 1.5 min at 72 ℃ （extension）, a final elongation step at 72 ℃ for 7 min.
文摘In this paper, the flexural behavior of laterally loaded tapered piles in cohesive soils is investigated. The exact solution for the governing differential equation of the problem is obtained based on the beam-on-elastic foundation approach in which the soil reaction on the pile is related directly to the pile lateral deflection. In this investigation, the modulus of subgrade reactions is assumed to be constant along the pile depth. Parametric study through numerical examples is carried out to prove the validity and accuracy of the obtained results. In general, the derived displacement field can be used to study pile response in multilayered soil profiles by subdividing the pile into a number of elements. It is found that tapered piles show stiffer behavior than that for prismatic ones having the same material volume with an optimum stress distribution along the pile depth. Accordingly, tapered piles are more efficient and economic than those having the same material volume. Verification is also carried out for the obtained results through finite element analysis and the selected number of elements gives a very good agreement for lateral deflection and a larger number of elements is required to obtain better results for bending moment because of moment loss resulting from the lack of shear diagram.
文摘The ideal reducing reagent in testing available nitrogen of soil by Conway Methodis Devard‘s alloy.The optimum ratio of soil:Devard’s alloy:1.0N NaOH solution is 5.0g:0.2g:5ml.When reaction goes on at 30℃ for 4 hours,the rate of soil NO<sub>3</sub>-N reduction is about 90%,and the recovery rate of soil NH<sub>4</sub>-N is about 95%.Some organic nitrogen can be measured at thesame time.This method is defined as the Modified Conway Method and the soil N-min is r=0.982（n=10）.In predicting soil nitrogen supplying power,the Modified Conway Method takesonly 1/6 of time needed by Conway Method.The Modified Conway Method can also be used forthe measure of soil N-min.
基金Project supported by the China Postdoctoral Science Foundation (No. 2012M521339)the Independent Innovation Foundation of Shandong University (No. 2012GN012),China
文摘This work presents a new analytical method to analyze the influence of reaction piles on the test pile response in a static load test.In our method,the interactive effect between soil and pile is simulated using independent springs and the shear displacement method is adopted to analyze the influence of reaction piles on test pile response.Moreover,the influence of the sheltering effect between reaction piles and test pile on the test pile response is taken into account.Two cases are analyzed to verify the rationality and efficiency of the present method.This method can be easily extended to a nonlinear response of an influenced test pile embedded in a multilayered soil,and the validity is also demonstrated using centrifuge model tests and a computer program presented in the literature.The present analyses indicate that the proposed method will lead to an underestimation of the test pile settlement in a static load test if the influence of the presence of reaction piles on the test pile response is neglected.
文摘Fluorine contaminates the environment. The study of fluorine contamination profile can be made easy by the use of nuclear analytic method. Measurement of prompt gamma emitted from bombarding fluorine polluted environmental sample with proton beam from accelerator provides rapid assessment of fluorine contamination. In this paper, 340 keV proton beam induced F 19 (P,αγ) O 16 reaction is performed, measurement of prompt gamma 6130 keV gives fluorine content in the soil and leaves of plants (parasol, cotton and glossy privet), taken from the fluorine polluted area.
