The self-absorption effect is one of the main factors affecting the quantitative analysis accuracy of laser-induced breakdown spectroscopy.In this paper,the self-absorption effects of laserinduced 7050 Al alloy plasma...The self-absorption effect is one of the main factors affecting the quantitative analysis accuracy of laser-induced breakdown spectroscopy.In this paper,the self-absorption effects of laserinduced 7050 Al alloy plasma under different pressures in air,Ar,and N2have been studied.Compared with air and N2,Ar significantly enhances the spectral signal.Furthermore,the spectral self-absorption coefficient is calculated to quantify the degree of self-absorption,and the influences of gas species and gas pressure on self-absorption are analyzed.In addition,it is found that the spectral intensity fluctuates with the change of pressure of three gases.It can also be seen that the fluctuation of spectral intensity with pressure is eliminated after correcting,which indicates that the self-absorption leads to the fluctuation of spectral intensity under different pressures.The analysis shows that the evolution of optical thin spectral lines with pressure in different gases is mainly determined by the gas properties and the competition between plasma confinement and Rayleigh–Taylor instability.展开更多
Perovskite/silicon tandem solar cells(PSTSCs) have exhibited huge technological potential for breaking the Shockley-Queisser limit of single-junction solar cells. The efficiency of P-I-N type PSTSCs has surpassed the ...Perovskite/silicon tandem solar cells(PSTSCs) have exhibited huge technological potential for breaking the Shockley-Queisser limit of single-junction solar cells. The efficiency of P-I-N type PSTSCs has surpassed the single-junction limit, while the performance of N-I-P type PSTSCs is far below the theoretical value. Here, we developed a composite electron transport layer for N-I-P type monolithic PSTSCs with enhanced open-circuit voltage(VOC) and power conversion efficiency(PCE). Lithium chloride(Li Cl) was added into the tin oxide(SnO_(2)) precursor solution, which simultaneously passivated the defects and increased the electron injection driving force at the electron transfer layer(ETL)/perovskite interface.Eventually, we achieved monolithic PSTSCs with an efficiency of 25.42% and V_(OC) of 1.92 V, which is the highest PCE and VOCin N-I-P type perovskite/Si tandem devices. This work on interface engineering for improving the PCE of monolithic PSTSCs may bring a new hot point about perovskite-based tandem devices.展开更多
Topological insulators are insulating in the bulkbut have metallic surface states. Its unique physicochemicalproperties can find numerous applications in electronics,spintronics, photonics, the energy sciences, and th...Topological insulators are insulating in the bulkbut have metallic surface states. Its unique physicochemicalproperties can find numerous applications in electronics,spintronics, photonics, the energy sciences, and thesignal control of transportation. We report an experimentalapproach to synthesize the high-quality single crystal oftopological insulator Bi2Te3 by using self-flux method. Weobtained the optimal preparation conditions by adjustingthe parameters of heat treatment, and successfully preparedthe single-crystal Bi2Te3 sample. The as-grown sampleshave a surface with bright metallic luster and are soft andfragile. Furthermore, Bi2Te3 has the obvious layer structurefrom SEM results. The data of X-ray diffraction andscanning electron microscope show that Bi2Te3 singlecrystal grows along the c-axis with the order of Te（1）–Bi–Te（2）–Bi–Te（1） and crystallizes in the hexagonal systemwith space group of R/3 m. The q–T curve shows that qdecreases with temperature, showing metallic behaviorover the whole temperature range.展开更多
Adoption of powder-in-tube method to fabricatesuperconducting wire can realize a large application ofNb3Al prepared by powder metallurgy. Powder metallurgywas used to synthesize Nb3Al under various heat-treatmentcondi...Adoption of powder-in-tube method to fabricatesuperconducting wire can realize a large application ofNb3Al prepared by powder metallurgy. Powder metallurgywas used to synthesize Nb3Al under various heat-treatmentconditions, annealing temperature was varied from 700 to1,000 C and heating time was varied from 10 to 50 h.X-ray diffraction patterns reveal that a reaction between Nband Al took place and formed NbAl3 phase. Under currentheat-treatment conditions （annealing temperature wasvaried from 700 to 1,000 C and heating time was variedfrom 10 to 50 h）, NbAl3 was so stable that it did not furtherreact with the unreacted Nb and was not sensitive to theheat-treatment condition. By mechanical alloying, adoptionof high-energy ball milling significantly decreases particlesize and enhances surface free energy, which promotes theformation of Nb3Al phase. X-ray diffraction patternsindicate that relatively pure Nb3Al phase was obtainedunder the same heat-treatment condition. Energy-dispersiveX-ray analysis measurement demonstrates that theobtained samples were close to the right stoichiometry ofA15 structure Nb3Al.展开更多
[Objectives]To explore the effects of budesonide aerosol inhalation on the perioperative pulmonary function of patients undergoing cardiopulmonary bypass valve replacement.[Methods]A total of 82 patients who underwent...[Objectives]To explore the effects of budesonide aerosol inhalation on the perioperative pulmonary function of patients undergoing cardiopulmonary bypass valve replacement.[Methods]A total of 82 patients who underwent cardiopulmonary bypass valve replacement during January 2018 and May 2019 in the Affiliated Hospital of Chengde Medical College were selected.They were divided into blank control group(group A,n=28),aerosol control group(group B,n=27,normal saline aerosol treatment),and experimental group(group C,n=27,budesonide aerosol treatment)by the random number table method.Corresponding treatments were given 5 d before surgery and 5 d after surgery,and the treatment effects of the 3 groups were compared.[Results]The clinical symptom scores of the patients in the experimental group were significantly lower than those in the blank control group and the aerosol control group,and the total effective rate of treatment was significantly higher than that in the blank control group.[Conclusions]Perioperative application of budesonide aerosol inhalation can effectively improve the clinical symptoms,treatment effect,and clinical prognosis of patients undergoing cardiopulmonary bypass valve replacement.展开更多
[Objectives] This study was conducted to explore the effects of new fly maggot protein feed on the mRNA expression of genes related to the TOR signaling pathway in loaches(Misgurnus anguillicaudatus). [Methods] Two ki...[Objectives] This study was conducted to explore the effects of new fly maggot protein feed on the mRNA expression of genes related to the TOR signaling pathway in loaches(Misgurnus anguillicaudatus). [Methods] Two kinds of test feed with equal nitrogen and energy were prepared by replacing 60% of the fish meal in the control group with the new fly maggot protein feed, i.e., Diet1(control group) and Diet2(60% fish meal replacement group). The feeding experiment was carried out in an indoor circulating water system, and the breeding period was 60 d. [Results] For the livers, the mRNA levels of TOR and 4EBP1 in the Diet2 group were significantly higher than those in the Diet1 group(P<0.05), while the expression of 4 EBP2 was lower than in the Diet1 group(P<0.05);and as to the muscles, the mRNA levels of TOR and 4EBP1 in the Diet2 group were significantly lower than those in the Diet1 group(P<0.05), while there was no significant change in the mRNA level of 4EBP2 between the two groups. [Conclusions] The replacement of fish meal by fly maggot cultures affected the mRNA expression of TOR, 4EBP1 and 4EBP2 in loach livers and muscles.展开更多
Chronic liver disease(CLD)entails elevated risk of COVID-19 severity and mortality.The effectiveness of the booster dose of inactivated SARS-CoV-2 vaccine in stimulating antibody response in CLD patients is unclear.Th...Chronic liver disease(CLD)entails elevated risk of COVID-19 severity and mortality.The effectiveness of the booster dose of inactivated SARS-CoV-2 vaccine in stimulating antibody response in CLD patients is unclear.Therefore,we conducted a cross-sectional study involving 237 adult CLD patients and 170 healthy controls(HC)to analyze neutralizing antibodies(NAbs)against SARS-CoV-2 prototype and BA.4/5 variant,anti-receptor binding domain(RBD)IgG,and total anti-SARS-CoV-2 antibodies.Serum levels of the total anti-SARS-CoV-2 antibodies,anti-RBD IgG and inhibition efficacy of NAbs were significantly elevated in CLD patients after the booster dose compared with the pre-booster dose,but were relatively lower than those of HCs.Induced humoral responses decreased over time after booster vaccination.The neutralization efficiency of the serum against BA.4/5 increased but remained below the inhibition threshold.All four SARS-CoV-2 antibodies,including total anti-SARS-CoV-2 antibodies,anti-RBD IgG and NAbs against prototype and BA.4/5,were lower in patients with severe CLD than those with non-severe CLD.After booster shot,age and time after the last vaccine were the risk factors for seropositivity of NAb against BA.4/5 in CLD patients.Additionally,white blood cell counts and hepatitis B core antibodies were the protective factors,and severe liver disease was the risk factor associated with seropositivity of total anti-SARS-CoV-2 antibodies.Overall,our data uncovered that antibody responses were improved in CLD patients and peaked at 120 days after the booster vaccines.All antibodies excepting total anti-SARS-CoV-2 antibodies declined after peak.CLD patients exhibited impaired immunologic responses to vaccination and weakened NAbs against BA.4/5,which hindered the protective effect of the booster shot against Omicron prevalence.Cellular immune responses should be further evaluated to determine the optimal vaccine regimen for CLD patients.展开更多
Aiming at the problems of uneven plant spacing,row spacing and sowing depth due to the collision of seeds with the tube wall or bouncing on the floor of the seed guide tube with the increase of operation speed of the ...Aiming at the problems of uneven plant spacing,row spacing and sowing depth due to the collision of seeds with the tube wall or bouncing on the floor of the seed guide tube with the increase of operation speed of the current corn no-till planter,in this study,the high-speed seed belt technology was combined with the finger clip seed discharge device,a kind of high-speed no-till planter monomer was designed and installed in high-speed seed tube.At the same time,simulation analysis was made on the movement law of seeds in the seed guide tube when they fell from the finger clip seeder and the main structural parameters and the range of key parameters of the high-speed seed tube were determined.Through the prototype,the single-factor and quadratic orthogonal rotational combination test method,and the machine operating speed,the height of the high-speed seed tube and the seed guide angle were selected as the test factors in the seeding performance test.After parameter optimization,the optimal working parameters were determined:the machine forward speed was 12.18 km/h,the height of the high-speed seed tube from the ground was 42.22 mm,and the seed guide angle of the high-speed seed tube was 8.82°.The field test verified that under this parameter combination,the qualified-seeding index was 94.95%,the multiple-seeding index was 2.37%,and the missing-seeding index was 2.48%,showing stable working performance and satisfied the sowing and agronomic requirements of the no-till seeding operation.展开更多
An adaptable product can satisfy different customer requirements by changing its configuration and parameter values during the operation stage. Design of adaptable products aims at reducing the environment impact thro...An adaptable product can satisfy different customer requirements by changing its configuration and parameter values during the operation stage. Design of adaptable products aims at reducing the environment impact through replacement of multiple different products with single adaptable ones. Due to the complex architec- ture, multiple functional requirements, and changes of product configurations and parameter values in operation, impact of uncertainties to the functional performance measures needs to be considered in design of adaptable products. In this paper, a robust design approach is introduced to identify the optimal design configuration and parameters of an adaptable product whose functional performance measures are the least sensitive to uncertain- ties. An adaptable product in this paper is modeled by both configurations and parameters. At the configuration level, methods to model different product configuration candi- dates in design and different product configuration states in operation to satisfy design requirements are introduced. At the parameter level, four types of product/operating parameters and relations among these parameters are discussed. A two-level optimization approach is developed to identify the optimal design configuration and its parameter values of the adaptable product. A case study is implemented to illustrate the effectiveness of the newly developed robust adaptable design method.展开更多
Air flow distribution in radial flow adsorber was numerically investigated using computational fluid dynamics(CFD)method,which was proved to be applicable to study the problem of non-uniform distribution in radial flo...Air flow distribution in radial flow adsorber was numerically investigated using computational fluid dynamics(CFD)method,which was proved to be applicable to study the problem of non-uniform distribution in radial flow adsorber.Results showed that the degree of non-uniformity was more serious in desorption process than that is adsorption process.Therefore,it was considered that the non-uniform distribution of flow in a radial flow adsorber was mainly manifested in the desorption process.Optimum design of distributor parameters can improve the flow distribution in adsorber.Meanwhile,three different structures of distributor and the effect of breathing valve were analyzed.Results revealed that truncated cone is more effective than tubular and conical distributors in flow distribution.By inserting the truncated cone in central channel,desorption uniformity was increased by 6.56%and the breakthrough time of CO_(2)was extended from 564s to 1138s in the adsorption process.The“dead zone”problem at the top of adsorber during the desorption process was solved by opening breathing valve,which prolonged the working life of adsorber and was proved to have less effect on the uniform of airflow.展开更多
Isolation forest and elliptic envelope are used to detect geochemical anomalies,and the bat algorithm was adopted to optimize the parameters of the two models.The two bat-optimized models and their default-parameter c...Isolation forest and elliptic envelope are used to detect geochemical anomalies,and the bat algorithm was adopted to optimize the parameters of the two models.The two bat-optimized models and their default-parameter counterparts were used to detect multivariate geochemical anomalies from the stream sediment survey data of 1:50000 scale collected from the Helong district,Jilin Province,China.Based on the data modeling results,the receiver operating characteristic(ROC)curve analysis was performed to evaluate the performance of the two bat-optimized models and their default-parameter counterparts.The results show that the bat algorithm can improve the performance of the two models by optimizing their parameters in geochemical anomaly detection.The optimal threshold determined by the Youden index was used to identify geochemical anomalies from the geochemical data points.Compared with the anomalies detected by the elliptic envelope models,the anomalies detected by the isolation forest models have higher spatial relationship with the mineral occurrences discovered in the study area.According to the results of this study and previous work,it can be inferred that the background population of the study area is complex,which is not suitable for the establishment of elliptic envelope model.展开更多
基金National Key Research and Development Program of China(Nos.2017YFE0301306,2017YFE0301300,and 2017YFE0301506)Fujian Province Industrial Guidance Project(No.2019H0011).
文摘The self-absorption effect is one of the main factors affecting the quantitative analysis accuracy of laser-induced breakdown spectroscopy.In this paper,the self-absorption effects of laserinduced 7050 Al alloy plasma under different pressures in air,Ar,and N2have been studied.Compared with air and N2,Ar significantly enhances the spectral signal.Furthermore,the spectral self-absorption coefficient is calculated to quantify the degree of self-absorption,and the influences of gas species and gas pressure on self-absorption are analyzed.In addition,it is found that the spectral intensity fluctuates with the change of pressure of three gases.It can also be seen that the fluctuation of spectral intensity with pressure is eliminated after correcting,which indicates that the self-absorption leads to the fluctuation of spectral intensity under different pressures.The analysis shows that the evolution of optical thin spectral lines with pressure in different gases is mainly determined by the gas properties and the competition between plasma confinement and Rayleigh–Taylor instability.
基金supported by the National Key Research and Development Program of China (Grant No.2018YFB1500103)the National Natural Science Foundation of China (Grant No.61674084)+4 种基金the Overseas Expertise Introduction Project for Discipline Innovation of Higher Education of China (Grant No.B16027)the Tianjin Science and Technology Project (Grant No.18ZXJMTG00220)the Fundamental Research Funds for the Central Universities of Nankai University (Grant Nos.63191736,ZB19500204)the Natural Science Foundation of Tianjin (Grant No.20JCQNJC02070)the China Postdoctoral Science Foundation (Grant No.2020T130317)。
文摘Perovskite/silicon tandem solar cells(PSTSCs) have exhibited huge technological potential for breaking the Shockley-Queisser limit of single-junction solar cells. The efficiency of P-I-N type PSTSCs has surpassed the single-junction limit, while the performance of N-I-P type PSTSCs is far below the theoretical value. Here, we developed a composite electron transport layer for N-I-P type monolithic PSTSCs with enhanced open-circuit voltage(VOC) and power conversion efficiency(PCE). Lithium chloride(Li Cl) was added into the tin oxide(SnO_(2)) precursor solution, which simultaneously passivated the defects and increased the electron injection driving force at the electron transfer layer(ETL)/perovskite interface.Eventually, we achieved monolithic PSTSCs with an efficiency of 25.42% and V_(OC) of 1.92 V, which is the highest PCE and VOCin N-I-P type perovskite/Si tandem devices. This work on interface engineering for improving the PCE of monolithic PSTSCs may bring a new hot point about perovskite-based tandem devices.
基金supported by the National Magnetic Confinement Fusion Science Program (Grant No. 2011GB112001)the Program of International S&T Cooperation (Grant No. 2013DFA 51050)+3 种基金the National Natural Science Foundation of China (Grant No. 11104224, 11004162, 51271155)the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20110184120029)the Fundamental Research Funds for the Central Universities (Grant No. 2682013ZT16, SWJTU11ZT31, 2682013CX004, SWJTU11BR063)the Science Foundation of Sichuan Province (Grant No. 2011JY0031, 2011JY0130)
文摘Topological insulators are insulating in the bulkbut have metallic surface states. Its unique physicochemicalproperties can find numerous applications in electronics,spintronics, photonics, the energy sciences, and thesignal control of transportation. We report an experimentalapproach to synthesize the high-quality single crystal oftopological insulator Bi2Te3 by using self-flux method. Weobtained the optimal preparation conditions by adjustingthe parameters of heat treatment, and successfully preparedthe single-crystal Bi2Te3 sample. The as-grown sampleshave a surface with bright metallic luster and are soft andfragile. Furthermore, Bi2Te3 has the obvious layer structurefrom SEM results. The data of X-ray diffraction andscanning electron microscope show that Bi2Te3 singlecrystal grows along the c-axis with the order of Te（1）–Bi–Te（2）–Bi–Te（1） and crystallizes in the hexagonal systemwith space group of R/3 m. The q–T curve shows that qdecreases with temperature, showing metallic behaviorover the whole temperature range.
基金supported by the National Magnetic Confinement Fusion Science Program (Grant No. 2011 GB112001)the Program of International S&T Cooperation (Grant No. 2013DFA51050)+3 种基金the National Natural Science Foundation of China (Grant Nos. 11104224, 11004162, 51377138, and 51302224)the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20110184120029)the Fundamental Research Funds for the Central Universities (Grant Nos. 2682013ZT16, SWJTU11ZT31, 2682013CX004, and SWJTU11BR063)the Science Foundation of Sichuan Province (Grant Nos. 2011JY0031 and 2011JY0130)
文摘Adoption of powder-in-tube method to fabricatesuperconducting wire can realize a large application ofNb3Al prepared by powder metallurgy. Powder metallurgywas used to synthesize Nb3Al under various heat-treatmentconditions, annealing temperature was varied from 700 to1,000 C and heating time was varied from 10 to 50 h.X-ray diffraction patterns reveal that a reaction between Nband Al took place and formed NbAl3 phase. Under currentheat-treatment conditions （annealing temperature wasvaried from 700 to 1,000 C and heating time was variedfrom 10 to 50 h）, NbAl3 was so stable that it did not furtherreact with the unreacted Nb and was not sensitive to theheat-treatment condition. By mechanical alloying, adoptionof high-energy ball milling significantly decreases particlesize and enhances surface free energy, which promotes theformation of Nb3Al phase. X-ray diffraction patternsindicate that relatively pure Nb3Al phase was obtainedunder the same heat-treatment condition. Energy-dispersiveX-ray analysis measurement demonstrates that theobtained samples were close to the right stoichiometry ofA15 structure Nb3Al.
基金Young Researcher Science and Technology Project of Scientific Research Fund for the Health Commission of Hebei Province(Directive Project:20200182)Self-financing Project for Science and Technology Plan of Chengde City of Hebei Province(202006A048).
文摘[Objectives]To explore the effects of budesonide aerosol inhalation on the perioperative pulmonary function of patients undergoing cardiopulmonary bypass valve replacement.[Methods]A total of 82 patients who underwent cardiopulmonary bypass valve replacement during January 2018 and May 2019 in the Affiliated Hospital of Chengde Medical College were selected.They were divided into blank control group(group A,n=28),aerosol control group(group B,n=27,normal saline aerosol treatment),and experimental group(group C,n=27,budesonide aerosol treatment)by the random number table method.Corresponding treatments were given 5 d before surgery and 5 d after surgery,and the treatment effects of the 3 groups were compared.[Results]The clinical symptom scores of the patients in the experimental group were significantly lower than those in the blank control group and the aerosol control group,and the total effective rate of treatment was significantly higher than that in the blank control group.[Conclusions]Perioperative application of budesonide aerosol inhalation can effectively improve the clinical symptoms,treatment effect,and clinical prognosis of patients undergoing cardiopulmonary bypass valve replacement.
基金Supported by General Project of Natural Science Research in Higher Education Institutions in Jiangsu Province(18KJD240001)Xuzhou Science and Technology Planning Project(KC19200)2018“Qinglan Project”of Jiangsu Higher Education Institutions。
文摘[Objectives] This study was conducted to explore the effects of new fly maggot protein feed on the mRNA expression of genes related to the TOR signaling pathway in loaches(Misgurnus anguillicaudatus). [Methods] Two kinds of test feed with equal nitrogen and energy were prepared by replacing 60% of the fish meal in the control group with the new fly maggot protein feed, i.e., Diet1(control group) and Diet2(60% fish meal replacement group). The feeding experiment was carried out in an indoor circulating water system, and the breeding period was 60 d. [Results] For the livers, the mRNA levels of TOR and 4EBP1 in the Diet2 group were significantly higher than those in the Diet1 group(P<0.05), while the expression of 4 EBP2 was lower than in the Diet1 group(P<0.05);and as to the muscles, the mRNA levels of TOR and 4EBP1 in the Diet2 group were significantly lower than those in the Diet1 group(P<0.05), while there was no significant change in the mRNA level of 4EBP2 between the two groups. [Conclusions] The replacement of fish meal by fly maggot cultures affected the mRNA expression of TOR, 4EBP1 and 4EBP2 in loach livers and muscles.
基金This work was supported by the Beijing Natural Science Foundation(M23008)the National Key Research and Development Program of China(2018YFE0207300)+2 种基金Beijing Municipal Science&Technology Commission(Z211100002521021)the National High Level Hospital Clinical Research Funding(2022-PUMCH-B-124)Key Research and Development Plan of Hebei Province,Special Health Innovation Project(22377744D).
文摘Chronic liver disease(CLD)entails elevated risk of COVID-19 severity and mortality.The effectiveness of the booster dose of inactivated SARS-CoV-2 vaccine in stimulating antibody response in CLD patients is unclear.Therefore,we conducted a cross-sectional study involving 237 adult CLD patients and 170 healthy controls(HC)to analyze neutralizing antibodies(NAbs)against SARS-CoV-2 prototype and BA.4/5 variant,anti-receptor binding domain(RBD)IgG,and total anti-SARS-CoV-2 antibodies.Serum levels of the total anti-SARS-CoV-2 antibodies,anti-RBD IgG and inhibition efficacy of NAbs were significantly elevated in CLD patients after the booster dose compared with the pre-booster dose,but were relatively lower than those of HCs.Induced humoral responses decreased over time after booster vaccination.The neutralization efficiency of the serum against BA.4/5 increased but remained below the inhibition threshold.All four SARS-CoV-2 antibodies,including total anti-SARS-CoV-2 antibodies,anti-RBD IgG and NAbs against prototype and BA.4/5,were lower in patients with severe CLD than those with non-severe CLD.After booster shot,age and time after the last vaccine were the risk factors for seropositivity of NAb against BA.4/5 in CLD patients.Additionally,white blood cell counts and hepatitis B core antibodies were the protective factors,and severe liver disease was the risk factor associated with seropositivity of total anti-SARS-CoV-2 antibodies.Overall,our data uncovered that antibody responses were improved in CLD patients and peaked at 120 days after the booster vaccines.All antibodies excepting total anti-SARS-CoV-2 antibodies declined after peak.CLD patients exhibited impaired immunologic responses to vaccination and weakened NAbs against BA.4/5,which hindered the protective effect of the booster shot against Omicron prevalence.Cellular immune responses should be further evaluated to determine the optimal vaccine regimen for CLD patients.
基金supported by the Liaoning Revitalization Talents Program(Grant No.XLYC2007043)Scientific Research Fund Project of Liaoning Province(Grant No.LJKZZ20220087)from China Liaoning Province.
文摘Aiming at the problems of uneven plant spacing,row spacing and sowing depth due to the collision of seeds with the tube wall or bouncing on the floor of the seed guide tube with the increase of operation speed of the current corn no-till planter,in this study,the high-speed seed belt technology was combined with the finger clip seed discharge device,a kind of high-speed no-till planter monomer was designed and installed in high-speed seed tube.At the same time,simulation analysis was made on the movement law of seeds in the seed guide tube when they fell from the finger clip seeder and the main structural parameters and the range of key parameters of the high-speed seed tube were determined.Through the prototype,the single-factor and quadratic orthogonal rotational combination test method,and the machine operating speed,the height of the high-speed seed tube and the seed guide angle were selected as the test factors in the seeding performance test.After parameter optimization,the optimal working parameters were determined:the machine forward speed was 12.18 km/h,the height of the high-speed seed tube from the ground was 42.22 mm,and the seed guide angle of the high-speed seed tube was 8.82°.The field test verified that under this parameter combination,the qualified-seeding index was 94.95%,the multiple-seeding index was 2.37%,and the missing-seeding index was 2.48%,showing stable working performance and satisfied the sowing and agronomic requirements of the no-till seeding operation.
文摘An adaptable product can satisfy different customer requirements by changing its configuration and parameter values during the operation stage. Design of adaptable products aims at reducing the environment impact through replacement of multiple different products with single adaptable ones. Due to the complex architec- ture, multiple functional requirements, and changes of product configurations and parameter values in operation, impact of uncertainties to the functional performance measures needs to be considered in design of adaptable products. In this paper, a robust design approach is introduced to identify the optimal design configuration and parameters of an adaptable product whose functional performance measures are the least sensitive to uncertain- ties. An adaptable product in this paper is modeled by both configurations and parameters. At the configuration level, methods to model different product configuration candi- dates in design and different product configuration states in operation to satisfy design requirements are introduced. At the parameter level, four types of product/operating parameters and relations among these parameters are discussed. A two-level optimization approach is developed to identify the optimal design configuration and its parameter values of the adaptable product. A case study is implemented to illustrate the effectiveness of the newly developed robust adaptable design method.
基金The project is funded by the Fundamental Research Funds for the Central Universities with No.3082017NS2017005.
文摘Air flow distribution in radial flow adsorber was numerically investigated using computational fluid dynamics(CFD)method,which was proved to be applicable to study the problem of non-uniform distribution in radial flow adsorber.Results showed that the degree of non-uniformity was more serious in desorption process than that is adsorption process.Therefore,it was considered that the non-uniform distribution of flow in a radial flow adsorber was mainly manifested in the desorption process.Optimum design of distributor parameters can improve the flow distribution in adsorber.Meanwhile,three different structures of distributor and the effect of breathing valve were analyzed.Results revealed that truncated cone is more effective than tubular and conical distributors in flow distribution.By inserting the truncated cone in central channel,desorption uniformity was increased by 6.56%and the breakthrough time of CO_(2)was extended from 564s to 1138s in the adsorption process.The“dead zone”problem at the top of adsorber during the desorption process was solved by opening breathing valve,which prolonged the working life of adsorber and was proved to have less effect on the uniform of airflow.
基金supported by the National Natural Science Foundation of China(Nos.41672322,41872244)。
文摘Isolation forest and elliptic envelope are used to detect geochemical anomalies,and the bat algorithm was adopted to optimize the parameters of the two models.The two bat-optimized models and their default-parameter counterparts were used to detect multivariate geochemical anomalies from the stream sediment survey data of 1:50000 scale collected from the Helong district,Jilin Province,China.Based on the data modeling results,the receiver operating characteristic(ROC)curve analysis was performed to evaluate the performance of the two bat-optimized models and their default-parameter counterparts.The results show that the bat algorithm can improve the performance of the two models by optimizing their parameters in geochemical anomaly detection.The optimal threshold determined by the Youden index was used to identify geochemical anomalies from the geochemical data points.Compared with the anomalies detected by the elliptic envelope models,the anomalies detected by the isolation forest models have higher spatial relationship with the mineral occurrences discovered in the study area.According to the results of this study and previous work,it can be inferred that the background population of the study area is complex,which is not suitable for the establishment of elliptic envelope model.
