The content of total sugar, sucrose, fructose and protein in the leaves of3-yr.-old Betula platyphylla was measured after the treatment by three exogenous sugar solutions(sucrose, fructose, glucose) and three high con...The content of total sugar, sucrose, fructose and protein in the leaves of3-yr.-old Betula platyphylla was measured after the treatment by three exogenous sugar solutions(sucrose, fructose, glucose) and three high concentrations of CO_2 (700, 1 400, 2 100 μL/L·L^(-1))for about a month in 1998. The results showed that spraying three exogenous sugar solutionsincreased markedly the content of sugar and protein of leaves under 700 μL·L^(-1) and 1 400μL·L^(-1) CO_2 The effect of spraying exogenous sucrose solution was the best among the threeexogenous sugars. The treatment of spraying exogenous sugar solution and 2 100 μL·L^(-1) CO_2constrained the accumulation of total sugar and protein of leaves. There was no difference inprotein content of leaves when spraying glucose and fructose solutions under 700 μL·L^(-1) and 1400 μL·L^(-1) CO_2. The treatment of 2 100 μL·L^(-1) CO_2 concentration significantly increasedthe contents of total sugar, sucrose, fructose, and protein of leaves compared with that of the 700μL·L^(-1) and 1 400 μL·L^(-1) CO_2 except the plants spraying fructose solution. There waspositive correlation between the content of sugar of leaves and CO_2 concentration when sprayingsame exogenous sugar solution.展开更多
Based on statistics, this paper reviews China＇s economic growth and industrial upgrade since the reform and opening up in 1978 and estimates the contribution of industrial restructuring to economic growth. With the y...Based on statistics, this paper reviews China＇s economic growth and industrial upgrade since the reform and opening up in 1978 and estimates the contribution of industrial restructuring to economic growth. With the years of schooling as the proxy variable of human capital, this paper describes changes in China＇s labor competence during the industrial restructuring process. Then, this paper estimates China＇s future human capital demand and shortage based on economic and demographic forecast. Lastly, this paper proposes recommendations for improving human capital in China with skills development and education.展开更多
This paper establishes the mathematical model in calculating the effective thermal conductivity and the effective mass diffusivity of dried layer of beef undergoing freeze drying process.First,experimental measurement...This paper establishes the mathematical model in calculating the effective thermal conductivity and the effective mass diffusivity of dried layer of beef undergoing freeze drying process.First,experimental measurements are done on the dehydrated quantity as well as temperature variations at different locations of the beef steak.Then the effective thermal conductivity and the effective mass diffusivity are calculated by applying the above mathematical model on the data of the dehydrated quantity.These two coefficients are further used in the calculation of temperature distribution.The result is in agreement with the measurement,thus confirming the correctness of the model and the values of the coefficients.展开更多
Developing efficient approaches for lignin upgrading is of interest for the industrial production of chemicals and fuels from renewable biomass.Electrocatalytic lignin upgrading powered by renewable electricity operat...Developing efficient approaches for lignin upgrading is of interest for the industrial production of chemicals and fuels from renewable biomass.Electrocatalytic lignin upgrading powered by renewable electricity operating under gentle conditions(at or near ambient pressures and temperatures)enables a decentralized production of chemicals and fuels.Herein,we will cover the structures of lignin and review the recent advances in the electrocatalytic lignin upgrade,the electrocatalytic depolymerization of lignin,and the electrocatalytic upgrading of lignin monomers to value-added chemicals and fuels.Finally,we provide insights into the main challenges and future perspectives of this field.展开更多
In this experiment, lignite was refined and processed through binderless briquette preparation process from low-rank coal and became briquette. Then, lignite and its briquette were pyrolysed as materials to compare th...In this experiment, lignite was refined and processed through binderless briquette preparation process from low-rank coal and became briquette. Then, lignite and its briquette were pyrolysed as materials to compare the nature of their pyrolysis. In this study, the experiment was carried out through a lab tube furnace, at a heating rate of 10 ~C/min, and the gas was analyzed and compared, which was collected at different temperatures. The results show that： in the pyrolysis temperature of 550-850 ℃, the semi-coke yield of briquette is 2%-6% higher than lignite, the tar yield of briquette is 2%-3% higher than lignite and the gas yield of briquette is 4%-9% less than lignite. The time required for complete release of the briquette is about 20 min less than lignite. The components in the pyrolysis gas of lignite and its briquette are the same, and their variation with the pyrolysis temperature is similar.展开更多
The quality of Yi＇an gas coal before and after low temperature upgrading under either a N2 or H2 atmosphere was examined by thermogravimetric and infrared analyses. The effect of upgrading on the prepared coke qualit...The quality of Yi＇an gas coal before and after low temperature upgrading under either a N2 or H2 atmosphere was examined by thermogravimetric and infrared analyses. The effect of upgrading on the prepared coke quality was analyzed. The results show that the carboxyl and phenolic hydroxyls in the coal molecular structure are removed after upgrading by low temperature pyrolysis under either N2 or Hz atmospheres. This improves coal caking properties to a certain extent. The upgrading effect under a Hz atmosphere is remarkably better than the effect observed after upgrading under N2. Compared to coke obtained from raw coal, the compressiveand micro-strength of the cokes obtained from upgraded coal are greatly improved. The effect on coke reactivity with CO2 is not significant. The best upgrading temperature for Yi＇an gas coal under either a N2 or H2 atmosphere is 250 or 275 ℃ respectively.展开更多
Inter-phase mass transfer is important to the design and performance of airlift loop reactors for either chemical or biochemical applications, and a good measurement technique is crucial for studying mass transfer in ...Inter-phase mass transfer is important to the design and performance of airlift loop reactors for either chemical or biochemical applications, and a good measurement technique is crucial for studying mass transfer in multiphase systems. According to the model of macro-scale mass transfer in airlift loop reactors, it was proved that the airlift loop reactor can be regarded as a continuous stirred tank reactor for measuring mass transfer coefficient. The calculated mass transfer coefficient on such a basis is different from the volumetric mass transfer coefficient in the macro-scale model and the difference is discussed. To describe the time delay of the probe response to the change of oxygen concentration in the liquid phase, a model taking into account the time constant of response is es-tablished. Sensitivity analysis shows that this model can be used to measure the volumetric mass transfer coefficient. Applying this model to the measurement of volumetric mass transfer coefficient in the loop reactor, results that co-incide with the turbulence theory in the literate were obtained.展开更多
In this paper, silt sediment is considered to be Bingham body, which is made up of coarse and fine particles in front of a hydraulic gate. The coarse and fine particles provide friction and shear stress in the course ...In this paper, silt sediment is considered to be Bingham body, which is made up of coarse and fine particles in front of a hydraulic gate. The coarse and fine particles provide friction and shear stress in the course of opening the gate. They constitute together the adhesion force of the sediment. Based on this viewpoint, this paper puts forward a formula for the effect of silt sediment on the lifting force. The formula includes gate weight, down-suction force, sealing rubber friction, plus-weight, water-column pressure, plus-silted-sediment weight and rolling(or sliding)-bearing friction. Finally, the verification results show that the formula has certain reliability and the calculation accuracy can meet the need of practical engineering.展开更多
Activated carbons （ACs） with different surface properties were prepared from different raw materials. N2 adsorption, pH value, Boehm titration, Temperature-programmed reduction （TPR） and FTIR were employed to char...Activated carbons （ACs） with different surface properties were prepared from different raw materials. N2 adsorption, pH value, Boehm titration, Temperature-programmed reduction （TPR） and FTIR were employed to characterize the pore structure and surface chemical properties of the ACs. The results show that AC from bituminous coal （AC-B） has more meso-pores, higher pH value, more carboxylic groups and basic site than ACs from coconut shell and hawthorn（AC-C, AC-H）. Oxygen in the mixture gas has great effect on S02 catalytic oxidation/oxidation ability of AC-B. In the absence of oxygen, the adsorbed SO2 on AC-B is 0.16 mmollg and the conversion ratio of adsorbed S02 to S03 is 22.07~; while in the presence of oxygen, the adsorbed amount of S02 is 0.42 retool/g, and all of the adsorbed S02 was totally converted to SO3. This feature of AC-B is consistent with its higher pH value, basic site and the reaction ability with H2 from TPR. The conversion ratios of S02 absorbed on both AC-C and AC-H were 100%, respectively.展开更多
A novel modified poly(dl-lactic acid) (PDLLA) was obtained by covalently grafting of maleic anhydride onto the backbone of PDLLA, attempting to improve PDLLA’s hydrophilicity and cell affinity and to provide reactive...A novel modified poly(dl-lactic acid) (PDLLA) was obtained by covalently grafting of maleic anhydride onto the backbone of PDLLA, attempting to improve PDLLA’s hydrophilicity and cell affinity and to provide reactive groups for further chemical modification. FTIR, 13C NMR and DSC were used to characterize the maleic anhydride-modified PDLLA.展开更多
基金This paper was supported by the National Natural Science Foundation of China (No. 39970627) and the Key Project of State Department of Science Technology (2002BA515B05).
文摘The content of total sugar, sucrose, fructose and protein in the leaves of3-yr.-old Betula platyphylla was measured after the treatment by three exogenous sugar solutions(sucrose, fructose, glucose) and three high concentrations of CO_2 (700, 1 400, 2 100 μL/L·L^(-1))for about a month in 1998. The results showed that spraying three exogenous sugar solutionsincreased markedly the content of sugar and protein of leaves under 700 μL·L^(-1) and 1 400μL·L^(-1) CO_2 The effect of spraying exogenous sucrose solution was the best among the threeexogenous sugars. The treatment of spraying exogenous sugar solution and 2 100 μL·L^(-1) CO_2constrained the accumulation of total sugar and protein of leaves. There was no difference inprotein content of leaves when spraying glucose and fructose solutions under 700 μL·L^(-1) and 1400 μL·L^(-1) CO_2. The treatment of 2 100 μL·L^(-1) CO_2 concentration significantly increasedthe contents of total sugar, sucrose, fructose, and protein of leaves compared with that of the 700μL·L^(-1) and 1 400 μL·L^(-1) CO_2 except the plants spraying fructose solution. There waspositive correlation between the content of sugar of leaves and CO_2 concentration when sprayingsame exogenous sugar solution.
文摘Based on statistics, this paper reviews China＇s economic growth and industrial upgrade since the reform and opening up in 1978 and estimates the contribution of industrial restructuring to economic growth. With the years of schooling as the proxy variable of human capital, this paper describes changes in China＇s labor competence during the industrial restructuring process. Then, this paper estimates China＇s future human capital demand and shortage based on economic and demographic forecast. Lastly, this paper proposes recommendations for improving human capital in China with skills development and education.
基金the National Natural Science Foundation of China!(No.597760 14 )
文摘This paper establishes the mathematical model in calculating the effective thermal conductivity and the effective mass diffusivity of dried layer of beef undergoing freeze drying process.First,experimental measurements are done on the dehydrated quantity as well as temperature variations at different locations of the beef steak.Then the effective thermal conductivity and the effective mass diffusivity are calculated by applying the above mathematical model on the data of the dehydrated quantity.These two coefficients are further used in the calculation of temperature distribution.The result is in agreement with the measurement,thus confirming the correctness of the model and the values of the coefficients.
文摘Developing efficient approaches for lignin upgrading is of interest for the industrial production of chemicals and fuels from renewable biomass.Electrocatalytic lignin upgrading powered by renewable electricity operating under gentle conditions(at or near ambient pressures and temperatures)enables a decentralized production of chemicals and fuels.Herein,we will cover the structures of lignin and review the recent advances in the electrocatalytic lignin upgrade,the electrocatalytic depolymerization of lignin,and the electrocatalytic upgrading of lignin monomers to value-added chemicals and fuels.Finally,we provide insights into the main challenges and future perspectives of this field.
文摘In this experiment, lignite was refined and processed through binderless briquette preparation process from low-rank coal and became briquette. Then, lignite and its briquette were pyrolysed as materials to compare the nature of their pyrolysis. In this study, the experiment was carried out through a lab tube furnace, at a heating rate of 10 ~C/min, and the gas was analyzed and compared, which was collected at different temperatures. The results show that： in the pyrolysis temperature of 550-850 ℃, the semi-coke yield of briquette is 2%-6% higher than lignite, the tar yield of briquette is 2%-3% higher than lignite and the gas yield of briquette is 4%-9% less than lignite. The time required for complete release of the briquette is about 20 min less than lignite. The components in the pyrolysis gas of lignite and its briquette are the same, and their variation with the pyrolysis temperature is similar.
文摘The quality of Yi＇an gas coal before and after low temperature upgrading under either a N2 or H2 atmosphere was examined by thermogravimetric and infrared analyses. The effect of upgrading on the prepared coke quality was analyzed. The results show that the carboxyl and phenolic hydroxyls in the coal molecular structure are removed after upgrading by low temperature pyrolysis under either N2 or Hz atmospheres. This improves coal caking properties to a certain extent. The upgrading effect under a Hz atmosphere is remarkably better than the effect observed after upgrading under N2. Compared to coke obtained from raw coal, the compressiveand micro-strength of the cokes obtained from upgraded coal are greatly improved. The effect on coke reactivity with CO2 is not significant. The best upgrading temperature for Yi＇an gas coal under either a N2 or H2 atmosphere is 250 or 275 ℃ respectively.
基金Supported by the Specialized Research Fund for the Program of Higher Education (No.20050003030) and byTsinghua-Zhongda Postdoctoral Fellowship Program (No.20283600131).
文摘Inter-phase mass transfer is important to the design and performance of airlift loop reactors for either chemical or biochemical applications, and a good measurement technique is crucial for studying mass transfer in multiphase systems. According to the model of macro-scale mass transfer in airlift loop reactors, it was proved that the airlift loop reactor can be regarded as a continuous stirred tank reactor for measuring mass transfer coefficient. The calculated mass transfer coefficient on such a basis is different from the volumetric mass transfer coefficient in the macro-scale model and the difference is discussed. To describe the time delay of the probe response to the change of oxygen concentration in the liquid phase, a model taking into account the time constant of response is es-tablished. Sensitivity analysis shows that this model can be used to measure the volumetric mass transfer coefficient. Applying this model to the measurement of volumetric mass transfer coefficient in the loop reactor, results that co-incide with the turbulence theory in the literate were obtained.
基金Supported by Shandong Province Outstanding Young Scientist Award Fund(No.BS2014SF016)the National Natural Science Foundation of China(No.50979067)+1 种基金Ludong University Doctor Introduction Foundation(No.LY2014026 and No.LY2014028)the Open Research Fund Program of State Key Laboratory of Water Resources and Hydropower Engineering Science(No.2012B104)
文摘In this paper, silt sediment is considered to be Bingham body, which is made up of coarse and fine particles in front of a hydraulic gate. The coarse and fine particles provide friction and shear stress in the course of opening the gate. They constitute together the adhesion force of the sediment. Based on this viewpoint, this paper puts forward a formula for the effect of silt sediment on the lifting force. The formula includes gate weight, down-suction force, sealing rubber friction, plus-weight, water-column pressure, plus-silted-sediment weight and rolling(or sliding)-bearing friction. Finally, the verification results show that the formula has certain reliability and the calculation accuracy can meet the need of practical engineering.
基金support from the National Natural Science Foundation of China (No.50204011)
文摘Activated carbons （ACs） with different surface properties were prepared from different raw materials. N2 adsorption, pH value, Boehm titration, Temperature-programmed reduction （TPR） and FTIR were employed to characterize the pore structure and surface chemical properties of the ACs. The results show that AC from bituminous coal （AC-B） has more meso-pores, higher pH value, more carboxylic groups and basic site than ACs from coconut shell and hawthorn（AC-C, AC-H）. Oxygen in the mixture gas has great effect on S02 catalytic oxidation/oxidation ability of AC-B. In the absence of oxygen, the adsorbed SO2 on AC-B is 0.16 mmollg and the conversion ratio of adsorbed S02 to S03 is 22.07~; while in the presence of oxygen, the adsorbed amount of S02 is 0.42 retool/g, and all of the adsorbed S02 was totally converted to SO3. This feature of AC-B is consistent with its higher pH value, basic site and the reaction ability with H2 from TPR. The conversion ratios of S02 absorbed on both AC-C and AC-H were 100%, respectively.
文摘A novel modified poly(dl-lactic acid) (PDLLA) was obtained by covalently grafting of maleic anhydride onto the backbone of PDLLA, attempting to improve PDLLA’s hydrophilicity and cell affinity and to provide reactive groups for further chemical modification. FTIR, 13C NMR and DSC were used to characterize the maleic anhydride-modified PDLLA.
