The effects of super absorbent polymers (SAP) on yield as well as water-saving and drought-escaping mechanism in spring maize in the seasonal drought region were studied. As shown by the results, during the seasonal...The effects of super absorbent polymers (SAP) on yield as well as water-saving and drought-escaping mechanism in spring maize in the seasonal drought region were studied. As shown by the results, during the seasonal drought in southern China, SAP treatment promoted the soil moisture, improved the capability of absorption and transportation of roots, promoted physiological and biochemical functions, increased the chlorophyll content, photosynthetic rate and intercellular CO2 concentration, and reduced the stomatal conductance and transplre.tion rate. As a result, the economic characters of spring maize were improved, and the yield was increased.展开更多
Aim To research the computer optimization design in material formulation. Methods The professional software including experimental design, mathematical modeling and optimization of single and multiple purposes was d...Aim To research the computer optimization design in material formulation. Methods The professional software including experimental design, mathematical modeling and optimization of single and multiple purposes was developed and applied to the formulation design for the flame retardant ethylenepropylene-diene mischpolymer (EPDM) insulation composites. With the aid of equipartition design, the mathematical models were established based on the optimization of the four properties (limiting oxygen index, volume resistance, tensile strength and elongation). Results The models from limited experiments had good significance, and the modeling analysis conclusions were in good agreement with later experiments. The optimization formulation was practically excellent. Conclusion The software enables practically a comprehensive multi-purpose use of material formulation research.展开更多
Li3V2(PO4)3 precursor was obtained with V2Os.nH2O , LiOH'H2O, NH4H2PO4 and sucrose as starting materials by grinding-sol-gel method, and then the monoclinic-typed Li3Vz(PO4)3 cathode material was prepared by sint...Li3V2(PO4)3 precursor was obtained with V2Os.nH2O , LiOH'H2O, NH4H2PO4 and sucrose as starting materials by grinding-sol-gel method, and then the monoclinic-typed Li3Vz(PO4)3 cathode material was prepared by sintering the amorphous Li3V2(PO4)3. The as-sintered samples were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption-desorption and electrochemical measurement. It is found that Li3Vz(PO4)3 sintered at 700 ℃ possesses good wormhole-like mesoporous structure with the largest specific surface area of 188 cmZ/g, and the smallest pore size of 9.3 nm. Electrochemical test reveals that the initial discharge capacity of the 700 ℃ sintered sample is 155.9 mA.h/g at the rate of 0.2C, and the capacity retains 154 mA.h/g after 50 cycles, exhibiting a stable discharge capacity at room temperature.展开更多
At present, the technology of biomass fuel composite molding technique is relatively lagging in China, which brings several negative influences, such as high energy consumption, short service life of the equipment. Th...At present, the technology of biomass fuel composite molding technique is relatively lagging in China, which brings several negative influences, such as high energy consumption, short service life of the equipment. The current situation of the biomass pellet fuel molding technology at home and abroad was introduced, and the development direction in China was put forward, which was of great significance for enhancing the level of pellet fuel molding technology in China.展开更多
The paper firstly reviews the developments of language transfer research. Utilizing the results supplied by CEM and AntConc, the present writer conducts analyses of the lexicai errors committed by the students in TEM-...The paper firstly reviews the developments of language transfer research. Utilizing the results supplied by CEM and AntConc, the present writer conducts analyses of the lexicai errors committed by the students in TEM-8 test and reveals the contributions to SLA and EFL language teaching that language transfer may make.展开更多
[Objective] This study aimed to investigate the feasibility of agricultural irri- gation with reclaimed water in Urumqi City. [Method] Chinese cabbages were used as experimental materials and irrigated with control wa...[Objective] This study aimed to investigate the feasibility of agricultural irri- gation with reclaimed water in Urumqi City. [Method] Chinese cabbages were used as experimental materials and irrigated with control water, 50% reclaimed water and 100% reclaimed water, and then the number of endophytic bacteria in Chinese cab- bages was measured. [Result] Using 50% reclaimed water, the fresh weight of Chi- nese cabbage was improved by 68.94%; however, with the deepening internalization of exogenous microorganism internalization, the total number of endophytic bacteria and coliform flock in Chinese cabbages treated with 50% reclaimed water was sig- nificantly higher than the other two treatment groups (P〈0.05). [Conclusion] Re- claimed water enhances both the weight of Chinese cabbage and the number of endophytic bacteria, which is unsuitable for irrigation of edible crops such as Chi- nese cabbage. Strengthening disinfection during the process of sewerage treatment could solve this problem.展开更多
AIM:To investigate the prevalence of gallstone dis-ease(GSD) and to evaluate the risk of symptomatic GSD among diabetic patients.METHODS:The study was conducted by analyzing the National Health Research Institutes(NHR...AIM:To investigate the prevalence of gallstone dis-ease(GSD) and to evaluate the risk of symptomatic GSD among diabetic patients.METHODS:The study was conducted by analyzing the National Health Research Institutes(NHRI) dataset of ambulatory care patients,inpatient claims,and the updated registry of beneficiaries from 2000 to 2008.A total of 615 532 diabetic patients without a prior history of hospital treatment or ambulatory care visits for symptomatic GSD were identified in the year 2000.Age-and gender-matched control individuals free from both GSD and diabetes from 1997 to 1999 were randomly selected from the NHIR database(n = 614 871).The incidence densities of symptomatic GSD were estimated according to the subjects' diabetic status.The distributions of age,gender,occupation,income,and residential area urbanization were compared between diabetic patients and control subjects using Cox proportion hazards models.Differences between the rates of selected comorbidities were also assessed in the two groups.RESULTS:Overall,60 734 diabetic patients and 48 116 control patients developed symptomatic GSD and underwent operations,resulting in cumulative operation rates of 9.87% and 7.83%,respectively.The age and gender distributions of both groups were similar,with a mean age of 60 years and a predominance of females.The diabetic group had a significantly higher prevalence of all comorbidities of interest.A higher incidence of symptomatic GSD was observed in females than in males in both groups.In the control group,females under the age of 64 had a significantly higher incidence of GSD than the corresponding males,but this difference was reduced with increasing age.The cumulative incidences of operations for symptomatic GSD in the diabetic and control groups were 13.06 and 9.52 cases per 1000 person-years,respectively.Diabetic men exhibited a higher incidence of operations for symptomatic GSD than did their counterparts in the control group(12.35 vs 8.75 cases per 1000 person-years).CONCLUSION:The association of diabetes with increased symptomatic GSD may provide insight to the treatment or management of diabetes in clinical settings.展开更多
The dynamic response of vitreous carbon to uniaxial strain loading has been investigated by means of the plate impact experiments. The two x cut shorted quartz gauges assembled with impactor and target were used ...The dynamic response of vitreous carbon to uniaxial strain loading has been investigated by means of the plate impact experiments. The two x cut shorted quartz gauges assembled with impactor and target were used to obtain the wave speeds in material and the stress histories at the sample gauge interface. The wave speed and stress histories were analyzed to determine the peak state in the sample. For compressive stress up to 4 0 GPa, the wave profiles were observed to be simple and steady, the uniaxial strain response is essentially nonlinear elastic, and no inelastic deformation has been found. All the experiment results indicate that the Hugoniot curve of vitreous carbon is concave downward just like that of fused silicon. There is no shock wave but the compressed wave propagating in the impacted samples.展开更多
The most important grinding processes were realized in a single pass of the grinding wheel,such as continuous path controlled grinding (CPCG/Peelgrinding/HSP),CPCG with reduced contact of the grinding wheel (Quickpoin...The most important grinding processes were realized in a single pass of the grinding wheel,such as continuous path controlled grinding (CPCG/Peelgrinding/HSP),CPCG with reduced contact of the grinding wheel (Quickpoint),single-pass longitudinal internal grinding,creep feed grinding (CFG),longitudinal cylindrical grinding with grinding wheels made of conventional abrasive materials and longitudinal internal cylindrical grinding using grinding wheels with zone-diversified structure.展开更多
Based on a method combined artificial neural network (ANN) with particle swarm optimization (PSO) algorithm, the thermo-mechanical fatigue reliability of plastic ball grid array (PBGA) solder joints was studied. The s...Based on a method combined artificial neural network (ANN) with particle swarm optimization (PSO) algorithm, the thermo-mechanical fatigue reliability of plastic ball grid array (PBGA) solder joints was studied. The simulation experiments of accelerated thermal cycling test were performed by ANSYS software. Based on orthogonal array experiments, a back-propagation artificial neural network (BPNN) was used to establish the nonlinear multivariate relationship between thermo-mechanical fatigue reliability and control factors. Then, PSO was applied to obtaining the optimal levels of control factors by using the output of BPNN as the affinity measure. The results show that the control factors, such as print circuit board (PCB) size, PCB thickness, substrate size, substrate thickness, PCB coefficient of thermal expansion (CTE), substrate CTE, silicon die CTE, and solder joint CTE, have a great influence on thermo-mechanical fatigue reliability of PBGA solder joints. The ratio of signal to noise of ANN-PSO method is 51.77 dB and its error is 33.3% less than that of Taguchi method. Moreover, the running time of ANN-PSO method is only 2% of that of the BPNN. These conclusions are verified by the confirmative experiments.展开更多
Peripheral nerve injury is a common clinical problem and affects the quality of life of patients. Traditional restoration methods are not satisfactory. Researchers increasingly focus on the field of tissue engineering...Peripheral nerve injury is a common clinical problem and affects the quality of life of patients. Traditional restoration methods are not satisfactory. Researchers increasingly focus on the field of tissue engineering. The three key points in establishing a tissue engineering material are the biological scaffold material, the seed cells and various growth factors. Understanding the type of nerve injury, the construction of scaffold and the process of repair are necessary to solve peripheral nerve injury and promote its regeneration. This review describes the categories of peripheral nerve injury, fundamental research of peripheral nervous tissue engineering and clinical research on peripheral nerve scaffold material, and paves a way for related research and the use of conduits in clinical practice.展开更多
It is of great significance for cleaner production to substitute bio-energy for fossil fuels in iron ore sintering. However, with the replacement ratio increasing, the consistency of heat front and flame front is brok...It is of great significance for cleaner production to substitute bio-energy for fossil fuels in iron ore sintering. However, with the replacement ratio increasing, the consistency of heat front and flame front is broken, and the thermal utilizing efficiency of fuel is reduced, which results in the decrease of yield and tumble index of sinter. Circulating flue gas to sintering bed as biochar replacing 40% coke, CO in flue gas can be reused so as to increase the thermal utilizing efficiency of fuels, and the consistency of two fronts is recovered for the circulating flue gas containing certain CO2, H2 O and lower O2, which contributes to increasing the maximum temperature, extending the high temperature duration time of sintering bed, and results in improving the output and quality of sinter. In the condition of circulating 40% flue gas, the sintering with biomass fuels is strengthened, and the sintering indexes with biomass fuel replacing 40% coke breeze are comparative to those of using coke breeze completely.展开更多
The performance of a rotating packed bed (RPter solutioB) with three kinds of packings was investigated using alcohol/wan under continuous distillation conditions at atmospheric pressure. The effects of average high...The performance of a rotating packed bed (RPter solutioB) with three kinds of packings was investigated using alcohol/wan under continuous distillation conditions at atmospheric pressure. The effects of average high gravity factor (β), reflux ratio (R), and feedstock flux (F) on mass-transfer in distillation were examined separately. Experimental results indicated that the total number of theoretical units (NTU) of RPB increased with β, R, and F.Of the three kinds of packings, the wave thread packing of stainless steel (Packing-Ⅲ)-had the best mass transfer efficiency with the height equivalent of a theoretical plate (HETP) of approximately 7.35 mm- 23.58 ram, whereas the corrugated disk pacing of stainless steel,(Packing Ⅰ) had the worst one with the HETP of about 13.4 mm-48.07 mm.Correlations were cleveloped to describe the mass transfer efficiency for packings Comparing.experimental data with the data calculated by correlation, the average deviate obtained for each packing was 0.72%, 1.98%, and 2.7%, respectively, implying that the accuracy of correlations developed was reasonable.展开更多
A kW-scale molten carbonate fuel cells stack was developed and 800-hours’ operating test and performance experimental research had been done. Utilizing domestic materials completely, we developed NiO cathode and Ni-A...A kW-scale molten carbonate fuel cells stack was developed and 800-hours’ operating test and performance experimental research had been done. Utilizing domestic materials completely, we developed NiO cathode and Ni-Al anode with the active area of 336cm 2 and Υ-LiAlO 2 electrolyte tile and bipolar plate with the area of 900cm 2. The stack was composed of thirty cells, with 62%Li 2CO 3+38%K 2CO 3 as its electrolyte. During the 800 hours’ continuous operating, the performance of the stack was stable. With 99.7%(mole fraction) H 2 as fuel and O 2 from air as oxidant, the average operating voltage of a cell was about 0.72 V. The maximal current density attained to 165mA/cm 2, and the maximal output power attained to 1080 Watt. The whole performance of the stack approached to the international level in the early 90’s. This paper gives the main works and experiments results.展开更多
The unique properties of carbon quantum dots (CQDs) make them promising materials in many ?elds. Herein, we present a facile method for the preparation of photo-luminescent CQDs using humins as the carbon precursor...The unique properties of carbon quantum dots (CQDs) make them promising materials in many ?elds. Herein, we present a facile method for the preparation of photo-luminescent CQDs using humins as the carbon precursor for the purpose of providing a high value-added solution for this “biomass conversion process waste”. The structure of the CQDs was analyzed, and the effects of reaction temperature and time on the CQDs’ ?uorescence were investigated. The results showed that humins were effectively carbonized during the reaction. The ?uorescence intensity of humin-based CQDs initially increased with reaction temperature and time, and subsequently decreased beyond 200℃ and 4 h. Polyaromatic structures and hydrophilic groups such as O-H, C-O, -COOH and C==O groups exist in the CQDs. The humin-based CQDs have the dimension of 3~7 nm with an average size of about 5.5 nm. The highest emission intensity of blue/cyan ?uorescence light at 440 nm is achieved on the excitation with UV light at the wavelength of 330 nm.展开更多
基金Supported by Key Projects in the National Science&TechnologyPillar Program(2006BAD04B07-2)Sic-tech Innovation Projectof Hunan Academy of Agricultural Sciences(2009hnnkycx30)~~
文摘The effects of super absorbent polymers (SAP) on yield as well as water-saving and drought-escaping mechanism in spring maize in the seasonal drought region were studied. As shown by the results, during the seasonal drought in southern China, SAP treatment promoted the soil moisture, improved the capability of absorption and transportation of roots, promoted physiological and biochemical functions, increased the chlorophyll content, photosynthetic rate and intercellular CO2 concentration, and reduced the stomatal conductance and transplre.tion rate. As a result, the economic characters of spring maize were improved, and the yield was increased.
文摘Aim To research the computer optimization design in material formulation. Methods The professional software including experimental design, mathematical modeling and optimization of single and multiple purposes was developed and applied to the formulation design for the flame retardant ethylenepropylene-diene mischpolymer (EPDM) insulation composites. With the aid of equipartition design, the mathematical models were established based on the optimization of the four properties (limiting oxygen index, volume resistance, tensile strength and elongation). Results The models from limited experiments had good significance, and the modeling analysis conclusions were in good agreement with later experiments. The optimization formulation was practically excellent. Conclusion The software enables practically a comprehensive multi-purpose use of material formulation research.
基金Project (51162026) supported by the National Natural Science Foundation of ChinaProjects (20100480949, 201104509) supported by China Postdoctoral Science FoundationProject (133274341015501) supported by Postdoctoral Science Foundation of Central South University, China
文摘Li3V2(PO4)3 precursor was obtained with V2Os.nH2O , LiOH'H2O, NH4H2PO4 and sucrose as starting materials by grinding-sol-gel method, and then the monoclinic-typed Li3Vz(PO4)3 cathode material was prepared by sintering the amorphous Li3V2(PO4)3. The as-sintered samples were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption-desorption and electrochemical measurement. It is found that Li3Vz(PO4)3 sintered at 700 ℃ possesses good wormhole-like mesoporous structure with the largest specific surface area of 188 cmZ/g, and the smallest pore size of 9.3 nm. Electrochemical test reveals that the initial discharge capacity of the 700 ℃ sintered sample is 155.9 mA.h/g at the rate of 0.2C, and the capacity retains 154 mA.h/g after 50 cycles, exhibiting a stable discharge capacity at room temperature.
基金Supported by the Special Fund for Agro-Scientific Research in the Public Interest(201003063)the Key Technology R&D Program of Jiangsu Province(BE2013412)the Fund for Independent Innovation of Agricultural Sciences in Jiangsu Province(XC(13)3030)~~
文摘At present, the technology of biomass fuel composite molding technique is relatively lagging in China, which brings several negative influences, such as high energy consumption, short service life of the equipment. The current situation of the biomass pellet fuel molding technology at home and abroad was introduced, and the development direction in China was put forward, which was of great significance for enhancing the level of pellet fuel molding technology in China.
文摘The paper firstly reviews the developments of language transfer research. Utilizing the results supplied by CEM and AntConc, the present writer conducts analyses of the lexicai errors committed by the students in TEM-8 test and reveals the contributions to SLA and EFL language teaching that language transfer may make.
基金Supported by National Natural Science Foundation of China(Grant No.30960178)Natural Science Foundation of Xinjiang Province(Grant No.200821126)~~
文摘[Objective] This study aimed to investigate the feasibility of agricultural irri- gation with reclaimed water in Urumqi City. [Method] Chinese cabbages were used as experimental materials and irrigated with control water, 50% reclaimed water and 100% reclaimed water, and then the number of endophytic bacteria in Chinese cab- bages was measured. [Result] Using 50% reclaimed water, the fresh weight of Chi- nese cabbage was improved by 68.94%; however, with the deepening internalization of exogenous microorganism internalization, the total number of endophytic bacteria and coliform flock in Chinese cabbages treated with 50% reclaimed water was sig- nificantly higher than the other two treatment groups (P〈0.05). [Conclusion] Re- claimed water enhances both the weight of Chinese cabbage and the number of endophytic bacteria, which is unsuitable for irrigation of edible crops such as Chi- nese cabbage. Strengthening disinfection during the process of sewerage treatment could solve this problem.
基金Supported by The Cheng-Hsin General Hospital and National Yang-Ming University
文摘AIM:To investigate the prevalence of gallstone dis-ease(GSD) and to evaluate the risk of symptomatic GSD among diabetic patients.METHODS:The study was conducted by analyzing the National Health Research Institutes(NHRI) dataset of ambulatory care patients,inpatient claims,and the updated registry of beneficiaries from 2000 to 2008.A total of 615 532 diabetic patients without a prior history of hospital treatment or ambulatory care visits for symptomatic GSD were identified in the year 2000.Age-and gender-matched control individuals free from both GSD and diabetes from 1997 to 1999 were randomly selected from the NHIR database(n = 614 871).The incidence densities of symptomatic GSD were estimated according to the subjects' diabetic status.The distributions of age,gender,occupation,income,and residential area urbanization were compared between diabetic patients and control subjects using Cox proportion hazards models.Differences between the rates of selected comorbidities were also assessed in the two groups.RESULTS:Overall,60 734 diabetic patients and 48 116 control patients developed symptomatic GSD and underwent operations,resulting in cumulative operation rates of 9.87% and 7.83%,respectively.The age and gender distributions of both groups were similar,with a mean age of 60 years and a predominance of females.The diabetic group had a significantly higher prevalence of all comorbidities of interest.A higher incidence of symptomatic GSD was observed in females than in males in both groups.In the control group,females under the age of 64 had a significantly higher incidence of GSD than the corresponding males,but this difference was reduced with increasing age.The cumulative incidences of operations for symptomatic GSD in the diabetic and control groups were 13.06 and 9.52 cases per 1000 person-years,respectively.Diabetic men exhibited a higher incidence of operations for symptomatic GSD than did their counterparts in the control group(12.35 vs 8.75 cases per 1000 person-years).CONCLUSION:The association of diabetes with increased symptomatic GSD may provide insight to the treatment or management of diabetes in clinical settings.
文摘The dynamic response of vitreous carbon to uniaxial strain loading has been investigated by means of the plate impact experiments. The two x cut shorted quartz gauges assembled with impactor and target were used to obtain the wave speeds in material and the stress histories at the sample gauge interface. The wave speed and stress histories were analyzed to determine the peak state in the sample. For compressive stress up to 4 0 GPa, the wave profiles were observed to be simple and steady, the uniaxial strain response is essentially nonlinear elastic, and no inelastic deformation has been found. All the experiment results indicate that the Hugoniot curve of vitreous carbon is concave downward just like that of fused silicon. There is no shock wave but the compressed wave propagating in the impacted samples.
文摘The most important grinding processes were realized in a single pass of the grinding wheel,such as continuous path controlled grinding (CPCG/Peelgrinding/HSP),CPCG with reduced contact of the grinding wheel (Quickpoint),single-pass longitudinal internal grinding,creep feed grinding (CFG),longitudinal cylindrical grinding with grinding wheels made of conventional abrasive materials and longitudinal internal cylindrical grinding using grinding wheels with zone-diversified structure.
基金Project(60371046) supported by the National Natural Science Foundation of ChinaProject(9140C0301060C03001) supported by the National Defense Science and Technology Foundation of Key Laboratory, China
文摘Based on a method combined artificial neural network (ANN) with particle swarm optimization (PSO) algorithm, the thermo-mechanical fatigue reliability of plastic ball grid array (PBGA) solder joints was studied. The simulation experiments of accelerated thermal cycling test were performed by ANSYS software. Based on orthogonal array experiments, a back-propagation artificial neural network (BPNN) was used to establish the nonlinear multivariate relationship between thermo-mechanical fatigue reliability and control factors. Then, PSO was applied to obtaining the optimal levels of control factors by using the output of BPNN as the affinity measure. The results show that the control factors, such as print circuit board (PCB) size, PCB thickness, substrate size, substrate thickness, PCB coefficient of thermal expansion (CTE), substrate CTE, silicon die CTE, and solder joint CTE, have a great influence on thermo-mechanical fatigue reliability of PBGA solder joints. The ratio of signal to noise of ANN-PSO method is 51.77 dB and its error is 33.3% less than that of Taguchi method. Moreover, the running time of ANN-PSO method is only 2% of that of the BPNN. These conclusions are verified by the confirmative experiments.
基金supported by the National Natural Science Foundation of China,No.31040043,31671248(to NH),No.81171146,81372044,30971526(to BGJ)the Chinese National Ministry of Science and Technology(973 Project),No.2014CB542201(to PXZ)+4 种基金the Ministry of Education Innovation Team,China,No.IRT1201(to PXZ)the Fostering Young Scholars of Peking University Health Science Center,China,No.BMU2017PY013(to PXZ)the Chinese National General Program of National Natural Science Fund,China(to PXZ)the Beijing City Science&Technology New Star Cross Project,China,No.2018019(to PXZ)the National Natural Science Foundation of China,No.31771322,31571235,51373023,21171019,31640045,31571236,31471144,31100860,31371210(to PXZ)
文摘Peripheral nerve injury is a common clinical problem and affects the quality of life of patients. Traditional restoration methods are not satisfactory. Researchers increasingly focus on the field of tissue engineering. The three key points in establishing a tissue engineering material are the biological scaffold material, the seed cells and various growth factors. Understanding the type of nerve injury, the construction of scaffold and the process of repair are necessary to solve peripheral nerve injury and promote its regeneration. This review describes the categories of peripheral nerve injury, fundamental research of peripheral nervous tissue engineering and clinical research on peripheral nerve scaffold material, and paves a way for related research and the use of conduits in clinical practice.
基金Projects(51174253,51304245) supported by National Natural Science Foundation of China
文摘It is of great significance for cleaner production to substitute bio-energy for fossil fuels in iron ore sintering. However, with the replacement ratio increasing, the consistency of heat front and flame front is broken, and the thermal utilizing efficiency of fuel is reduced, which results in the decrease of yield and tumble index of sinter. Circulating flue gas to sintering bed as biochar replacing 40% coke, CO in flue gas can be reused so as to increase the thermal utilizing efficiency of fuels, and the consistency of two fronts is recovered for the circulating flue gas containing certain CO2, H2 O and lower O2, which contributes to increasing the maximum temperature, extending the high temperature duration time of sintering bed, and results in improving the output and quality of sinter. In the condition of circulating 40% flue gas, the sintering with biomass fuels is strengthened, and the sintering indexes with biomass fuel replacing 40% coke breeze are comparative to those of using coke breeze completely.
基金the Specialized Research Fund for the Doctoral Program of Higher Education of China(20060110003)
文摘The performance of a rotating packed bed (RPter solutioB) with three kinds of packings was investigated using alcohol/wan under continuous distillation conditions at atmospheric pressure. The effects of average high gravity factor (β), reflux ratio (R), and feedstock flux (F) on mass-transfer in distillation were examined separately. Experimental results indicated that the total number of theoretical units (NTU) of RPB increased with β, R, and F.Of the three kinds of packings, the wave thread packing of stainless steel (Packing-Ⅲ)-had the best mass transfer efficiency with the height equivalent of a theoretical plate (HETP) of approximately 7.35 mm- 23.58 ram, whereas the corrugated disk pacing of stainless steel,(Packing Ⅰ) had the worst one with the HETP of about 13.4 mm-48.07 mm.Correlations were cleveloped to describe the mass transfer efficiency for packings Comparing.experimental data with the data calculated by correlation, the average deviate obtained for each packing was 0.72%, 1.98%, and 2.7%, respectively, implying that the accuracy of correlations developed was reasonable.
基金ShanghaiScienceandTechnologyDevelopmentFunds (No .9930 12 0 13),andtheNational985ScientificProjectDevelopmentFundsandpartoffundsupportofShanghaiElectricalGroups
文摘A kW-scale molten carbonate fuel cells stack was developed and 800-hours’ operating test and performance experimental research had been done. Utilizing domestic materials completely, we developed NiO cathode and Ni-Al anode with the active area of 336cm 2 and Υ-LiAlO 2 electrolyte tile and bipolar plate with the area of 900cm 2. The stack was composed of thirty cells, with 62%Li 2CO 3+38%K 2CO 3 as its electrolyte. During the 800 hours’ continuous operating, the performance of the stack was stable. With 99.7%(mole fraction) H 2 as fuel and O 2 from air as oxidant, the average operating voltage of a cell was about 0.72 V. The maximal current density attained to 165mA/cm 2, and the maximal output power attained to 1080 Watt. The whole performance of the stack approached to the international level in the early 90’s. This paper gives the main works and experiments results.
基金supported by the Research Project for Hot Tracking Items of Beijing Forestry University(2017BLRD03)the National Natural Science Foundation of China(51603012)Beijing Municipal Natural Science Foundation(6182031)
文摘The unique properties of carbon quantum dots (CQDs) make them promising materials in many ?elds. Herein, we present a facile method for the preparation of photo-luminescent CQDs using humins as the carbon precursor for the purpose of providing a high value-added solution for this “biomass conversion process waste”. The structure of the CQDs was analyzed, and the effects of reaction temperature and time on the CQDs’ ?uorescence were investigated. The results showed that humins were effectively carbonized during the reaction. The ?uorescence intensity of humin-based CQDs initially increased with reaction temperature and time, and subsequently decreased beyond 200℃ and 4 h. Polyaromatic structures and hydrophilic groups such as O-H, C-O, -COOH and C==O groups exist in the CQDs. The humin-based CQDs have the dimension of 3~7 nm with an average size of about 5.5 nm. The highest emission intensity of blue/cyan ?uorescence light at 440 nm is achieved on the excitation with UV light at the wavelength of 330 nm.