A computational model of two stage double helical tooth planetary gear set is employed to built the lateraltorsional coupling dynamic governing equations. Base on the dynamic equation, the free vibration properties ...A computational model of two stage double helical tooth planetary gear set is employed to built the lateraltorsional coupling dynamic governing equations. Base on the dynamic equation, the free vibration properties of the system with unequally spaced planets and stars are analyzed. The vibration modes are classified into three types: star mode, planet mode, and coupling mode. For each of the modes, the relation between inherent frequency and vibration amplitude is investigated in detail by the eigenvalue and mode characteristics.展开更多
In order to understand the key mechanisms of the composting processes, the municipal solid waste(MSW) composting processes were divided into two stages, and the characteristics of typical experimental scenarios from t...In order to understand the key mechanisms of the composting processes, the municipal solid waste(MSW) composting processes were divided into two stages, and the characteristics of typical experimental scenarios from the viewpoint of microbial kinetics was analyzed. Through experimentation with advanced composting reactor under controlled composting conditions, several equations were worked out to simulate the degradation rate of the substrate. The equations showed that the degradation rate was controlled by concentration of microbes in the first stage. The degradation rates of substrates of inoculation Run A, B, C and Control composting systems were 13 61 g/(kg·h), 13 08 g/(kg·h), 15 671 g/(kg·h), and 10 5 g/(kg·h), respectively. The value of Run C is around 1 5 times higher than that of Control system. The decomposition rate of the second stage is controlled by concentration of substrate. Although the organic matter degradation rates were similar to all Runs, inoculation could reduce the values of the half velocity coefficient K \-m and could be more efficient to make the composting stable. Particularly, for Run C, the degradation rate is high in the first stage, and K \-m is low in the second stage. The results indicated that the inoculation was efficient for the composting processes.展开更多
Multivariate seemingly unrelated regression system is raised first and the two stage estimation and its covariance matrix are given. The results of the literatures[1-5] are extended in this paper.
In some domain expert's decision-making is intelligent output by comprehensive analysis and reasoning for the numerous decision-making factors,constraints and the goal in their domain,it is the concentrated expres...In some domain expert's decision-making is intelligent output by comprehensive analysis and reasoning for the numerous decision-making factors,constraints and the goal in their domain,it is the concentrated expression of domain knowledge.Be aimed at field knowledge induction;sum up the exploration with systematization method,the two stages case-based reasoning(CBR)technology on the basis of the expert decision cased is present.The main idea,according to the characteristic of problem,analysis and decision process of field expert is carried out case-reasoning by two steps,and the field knowledge can be classified,induction and accumulated from different angles by multi case libraries.This technology includes two aspects,first,through two state case-based reasoning mechanisms to achieve area of decision-making process simulation;second,the CBR service in two more cases of library design process.First,two stage case-based reasoning mechanism,the first stage case-based reasoning to analyze the main level,clear nature of the problem,type,degree and character as the main content;the second stage case reasoning takes first order case reasoning result as basis then,the case reasoning,gives to making policy holding out being that purpose is in progress to out a decision-making suggestion once again.Secondly,in many cases the design of the library,to serve two-stage case-based reasoning process,the design of the four case libraries:First,property type case library,is a static case base can be modified,the effect is to performance differences between actual case and plan case of the qualitative distinction,indicate difference type attribute;Second,hierarchic quantization case library,is a static case base can be modified,the effect is to performance differences between actual case and plan case the quantitative distinction between the scope,indicate degree,size that the type issues in some difference etc.Three are that decision-making supports case library,is a static case base can be modified,the effect is similar enumeration all possible decision-makings content,indicate the decision-making that field expert possibility carries out;Four are decision match case library,is a self-study and dynamic case library,the effect is the library recording history decision-making case,is used to gain the decision-making scheme specifically for current reality achievement case is similar,to provide the support making policy,to learn composing in reply the case accumulating the new decision-making at the same time.The method is based on real business needs for research and development obtained after the conclusion,the paper shows through examples of the technology industry has a good adaptability,practicality and effectiveness.展开更多
The double fire two stage method of underground coal gasification was suggested. On the basis of material balance, the ideal gasification parameters were calculated, and the field test process was briefly introduced. ...The double fire two stage method of underground coal gasification was suggested. On the basis of material balance, the ideal gasification parameters were calculated, and the field test process was briefly introduced. In addition, the cause for a middle to a high heat value of water gas was described. And the reasonableness and feasiblity of the method was proved, showing that the double fire two stage gasification is an important technique for commercialized production.展开更多
Gall bladder torsion(GBT) is a relatively uncommon entity and rarely diagnosed preoperatively. A constant factor in all occurrences of GBT is a freely mobile gall bladder due to congenital or acquired anomalies. GBT i...Gall bladder torsion(GBT) is a relatively uncommon entity and rarely diagnosed preoperatively. A constant factor in all occurrences of GBT is a freely mobile gall bladder due to congenital or acquired anomalies. GBT is commonly observed in elderly white females. We report a 77-year-old, Caucasian lady who was originally diagnosed as gall bladder perforation but was eventually found with a two staged torsion of the gall bladder with twisting of the Riedel's lobe(part of tongue like projection of liver segment 4A). This together, has not been reported in literature, to the best of our knowledge. We performed laparoscopic cholecystectomy and she had an uneventful postoperative period. GBT may create a diagnostic dilemma in the context of acute cholecystitis. Timely diagnosis and intervention is necessary, with extra care while operating as the anatomy is generally distorted. The fundus first approach can be useful due to altered anatomy in the region of Calot's triangle. Laparoscopic cholecystectomy has the benefit of early recovery.展开更多
Non-response is a regular occurrence in Sample Surveys. Developing estimators when non-response exists may result in large biases when estimating population parameters. In this paper, a finite population mean is estim...Non-response is a regular occurrence in Sample Surveys. Developing estimators when non-response exists may result in large biases when estimating population parameters. In this paper, a finite population mean is estimated when non-response exists randomly under two stage cluster sampling with replacement. It is assumed that non-response arises in the survey variable in the second stage of cluster sampling. Weighting method of compensating for non-response is applied. Asymptotic properties of the proposed estimator of the population mean are derived. Under mild assumptions, the estimator is shown to be asymptotically consistent.展开更多
We study a two stage queuing model where the server provides two stages of service one by one in succession. We consider reneging to occur when the server is unavailable during the system breakdown or vacation periods...We study a two stage queuing model where the server provides two stages of service one by one in succession. We consider reneging to occur when the server is unavailable during the system breakdown or vacation periods. We concentrate on deriving the steady state solutions by using supplementary variable technique and calculate the mean queue length and mean waiting time. Further some special cases are also discussed and numerical examples are presented.展开更多
A two stage turbocharging control system was proposed,in which the pressure regulator valve with a close-loop pressure adjusting function instead of a high speed on-off solenoid valve,is used as a driving mechanism of...A two stage turbocharging control system was proposed,in which the pressure regulator valve with a close-loop pressure adjusting function instead of a high speed on-off solenoid valve,is used as a driving mechanism of waste gate.A digital-analog（DA）conversion circuit based on pulse width modulation（PWM）generates one analog voltage signal required by the pressure regulating valve control.The principle of the DA conversion circuit was analyzed,meanwhile,the performance of the conversion circuit was improved by adopting a speed-up capacitor,which helps to increase the stability and responsiveness of the control voltage generated by the conversion circuit;the structure parameters of the circuit was optimized by simulation.After the optimization,the ripple wave of circuit output voltage was kept within16mV under the 12bit conversion accuracy,the conversion time of the circuit could be reduced to 4ms.The engine bench test show that the turbocharging boost pressure control system which adopted the circuit had a rather good stable control accuracy（the steady state within 0.8%）and dynamic response（the regulation time is less than 4s）.展开更多
The full bridge zero voltage zero current switching （ FB-ZVZCS ） , which could adjust the output power by keeping the duty ratio of lagging leg constant and changing the duty ratio of leading leg, was a common circu...The full bridge zero voltage zero current switching （ FB-ZVZCS ） , which could adjust the output power by keeping the duty ratio of lagging leg constant and changing the duty ratio of leading leg, was a common circuit of soft switching arc welding inverter power source. However, when the duty ratio of leading leg was reduced to zero, the output power stayed the constant value instead of becoming zero. The working status and waveforms of some major parameters were studied in this paper while the duty ratio of leading leg was zero. It was concluded that the minimum output power of soft switching inverter was related to the charging voltage of paraUel capacitors, and the output power also could be reduced by reducing the duty ratio of lagging leg. A novel two-stage continuous PWM control method that could switch working-mode between full bridge and half bridge was put forward in this paper. This kind of control method could further reduce the output power of soft switching inverter in order to meet the requirement of low heat input of sheet metal welding.展开更多
The paper deals with the comparative analysis of the performance of cooling and heating systems operating with NH3 （ammonia） or CO2 （carbon dioxide）, both natural refrigerants. The study is based on the exergetic ...The paper deals with the comparative analysis of the performance of cooling and heating systems operating with NH3 （ammonia） or CO2 （carbon dioxide）, both natural refrigerants. The study is based on the exergetic analysis that points out the location and the magnitude of a system malfunction. Both systems, with NH3 or CO2 operate in two stages. The exergetic analysis gives the direction of the structural optimization. The exergetic analysis has shown that the best structural schematic is not the same for the two agents. The exergetic analysis points out that the largest exergy destruction in the CO2 cycle is due to the throttling process and offers solutions to diminish it.展开更多
AIM: To assess the cost-effectiveness of two populationbased hepatocellular carcinoma(HCC) screening programs, two-stage biomarker-ultrasound method and mass screening using abdominal ultrasonography(AUS).METHODS: In ...AIM: To assess the cost-effectiveness of two populationbased hepatocellular carcinoma(HCC) screening programs, two-stage biomarker-ultrasound method and mass screening using abdominal ultrasonography(AUS).METHODS: In this study, we applied a Markov decision model with a societal perspective and a lifetime horizon for the general population-based cohorts in an area with high HCC incidence, such as Taiwan. The accuracy of biomarkers and ultrasonography was estimated from published meta-analyses. The costs of surveillance, diagnosis, and treatment were based on a combination of published literature, Medicare payments, and medical expenditure at the National Taiwan University Hospital. The main outcome measure was cost per lifeyear gained with a 3% annual discount rate. RESULTS: The results show that the mass screening using AUS was associated with an incremental costeffectiveness ratio of USD39825 per life-year gained, whereas two-stage screening was associated with an incremental cost-effectiveness ratio of USD49733 per life-year gained, as compared with no screening. Screening programs with an initial screening age of 50 years old and biennial screening interval were the most cost-effective. These findings were sensitive to the costs of screening tools and the specificity of biomarker screening.CONCLUSION: Mass screening using AUS is more cost effective than two-stage biomarker-ultrasound screening. The most optimal strategy is an initial screening age at 50 years old with a 2-year inter-screening interval.展开更多
A two-stage UASB reactor was employed to remove sulfate from acrylic fiber manufacturing wastewater.Mesophilic operation（35±0.5℃） was performed with hydraulic retention time（HRT） varied between 28 and 40 hr....A two-stage UASB reactor was employed to remove sulfate from acrylic fiber manufacturing wastewater.Mesophilic operation（35±0.5℃） was performed with hydraulic retention time（HRT） varied between 28 and 40 hr.Mixed liquor suspended solids（MLSS） in the reactor was maintained about 8000 mg/L.The results indicated that sulfate removal was enhanced with increasing the ratio of COD/SO24-.At low COD/SO42-,the growth of the sulfate-reducing bacteria（SRB） was carbon-limited.The optimal sulfate removal efficiencies were 75% when the HRT was no less than 38 hr.Sulfidogenesis mainly happened in the sulfate-reducing stage,while methanogenesis in the methane-producing stage.Microbes in sulfate-reducing stage performed granulation better than that in methaneproducing stage.Higher extracellular polymeric substances（EPS） content in sulfate-reducing stage helped to adhere and connect the flocculent sludge particles together.SRB accounted for about 31% both in sulfate-reducing stage and methane-producing stage at COD/SO42-ratio of 0.5,while it dropped dramatically from 34% in sulfate-reducing stage to 10% in methane-producing stage corresponding to the COD/SO42-ratio of 4.7.SRB and MPA were predominant in sulfate-reducing stage and methane-producing stage respectively.展开更多
Poria cocos(Schw.) Wolf, an important medicinal and food fungus, is well known in East Asia. Due to growing market demand, long cultivation period, and consumption of pine trunk during cultivation, developing alternat...Poria cocos(Schw.) Wolf, an important medicinal and food fungus, is well known in East Asia. Due to growing market demand, long cultivation period, and consumption of pine trunk during cultivation, developing alternative methods for producing P. cocos and/or its active components is of interest. In the present study, the effects of different culture methods on biomass and accumulation of four triterpenoids were investigated. The ethanol extract of fermented mycelium(EFM) was orally administered to rats. Urine output and concentrations of electrolytes(Na^+, K^+, and Cl^-) were measured. Our results showed that mycelia grew better under continuous shaking culture condition(7.5 g DW·L^(-1)), and higher triterpenoid levels were accumulated in two-stage culture(112 mg·L-1, 2.03%). The optimal starting time of static culture for triterpenoid yield was 4^(th) d after shaking culture. Single administration of middle and high dose of EFM significantly increased urine output, Na^+ and Cl^- excretion, and Na^+/K^+ ratio. These results suggested that ethanol extract of cultured mycelia showed significant diuretic activity in rats and two-stage culture of P. cocos could be an alternative way to produce mycelia and triterpenoids.展开更多
Oil and gas pipeline networks are a key link in the coordinated development of oil and gas both upstream and downstream.To improve the reliability and safety of the oil and gas pipeline network, inspections are implem...Oil and gas pipeline networks are a key link in the coordinated development of oil and gas both upstream and downstream.To improve the reliability and safety of the oil and gas pipeline network, inspections are implemented to minimize the risk of leakage, spill and theft, as well as documenting actual incidents. In recent years, unmanned aerial vehicles have been recognized as a promising option for inspection due to their high efficiency. However, the integrated optimization of unmanned aerial vehicle inspection for oil and gas pipeline networks, including physical feasibility, the performance of mission, cooperation, real-time implementation and three-dimensional(3-D) space, is a strategic problem due to its large-scale,complexity as well as the need for efficiency. In this work, a novel mixed-integer nonlinear programming model is proposed that takes into account the constraints of the mission scenario and the safety performance of unmanned aerial vehicles. To minimize the total length of the inspection path, the model is solved by a two-stage solution method. Finally, a virtual pipeline network and a practical pipeline network are set as two examples to demonstrate the performance of the optimization schemes. Moreover, compared with the traditional genetic algorithm and simulated annealing algorithm, the self-adaptive genetic simulated annealing algorithm proposed in this paper provides strong stability.展开更多
Different artificial two-stage ageing behaviors and their effect on stress corrosion cracking （SCC） susceptibility of AI-Zn-Mg alloy have been investigated. The experimental results show that two hardness peaks pres...Different artificial two-stage ageing behaviors and their effect on stress corrosion cracking （SCC） susceptibility of AI-Zn-Mg alloy have been investigated. The experimental results show that two hardness peaks present on the second-stage ageing-hardening curve when the first-stage ageing is dealt with comparatively lower temperature than the conventional one. The first peak is caused by dispersive and evenly distributed G.P. zones, while η ′phases and coarsened G.P. zones contribute to the second peak. Tensile strength of experimental alloy raises 9.6% （33.2 MPa） and SCC susceptibility decreases 38.9% by applying the second peak ageing regime instead of conventional T73. AI-Zn-Mg alloy obtains high strength and SCC resistance due to its finely dispersive matrix precipitates （MPts）, coarsened and discontinuous grain boundary precipitates （GBPs）, as well as the narrow precipitate free zone （PFZ） in the second peak ageing condition. 2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.展开更多
基金Sponsored by the Programme of Introducing Talents of Discipline to Universities (the 111 Project)(Grant No. B07018)
文摘A computational model of two stage double helical tooth planetary gear set is employed to built the lateraltorsional coupling dynamic governing equations. Base on the dynamic equation, the free vibration properties of the system with unequally spaced planets and stars are analyzed. The vibration modes are classified into three types: star mode, planet mode, and coupling mode. For each of the modes, the relation between inherent frequency and vibration amplitude is investigated in detail by the eigenvalue and mode characteristics.
文摘In order to understand the key mechanisms of the composting processes, the municipal solid waste(MSW) composting processes were divided into two stages, and the characteristics of typical experimental scenarios from the viewpoint of microbial kinetics was analyzed. Through experimentation with advanced composting reactor under controlled composting conditions, several equations were worked out to simulate the degradation rate of the substrate. The equations showed that the degradation rate was controlled by concentration of microbes in the first stage. The degradation rates of substrates of inoculation Run A, B, C and Control composting systems were 13 61 g/(kg·h), 13 08 g/(kg·h), 15 671 g/(kg·h), and 10 5 g/(kg·h), respectively. The value of Run C is around 1 5 times higher than that of Control system. The decomposition rate of the second stage is controlled by concentration of substrate. Although the organic matter degradation rates were similar to all Runs, inoculation could reduce the values of the half velocity coefficient K \-m and could be more efficient to make the composting stable. Particularly, for Run C, the degradation rate is high in the first stage, and K \-m is low in the second stage. The results indicated that the inoculation was efficient for the composting processes.
基金Supported by the NSF of Henan Province(0611052600)
文摘Multivariate seemingly unrelated regression system is raised first and the two stage estimation and its covariance matrix are given. The results of the literatures[1-5] are extended in this paper.
文摘In some domain expert's decision-making is intelligent output by comprehensive analysis and reasoning for the numerous decision-making factors,constraints and the goal in their domain,it is the concentrated expression of domain knowledge.Be aimed at field knowledge induction;sum up the exploration with systematization method,the two stages case-based reasoning(CBR)technology on the basis of the expert decision cased is present.The main idea,according to the characteristic of problem,analysis and decision process of field expert is carried out case-reasoning by two steps,and the field knowledge can be classified,induction and accumulated from different angles by multi case libraries.This technology includes two aspects,first,through two state case-based reasoning mechanisms to achieve area of decision-making process simulation;second,the CBR service in two more cases of library design process.First,two stage case-based reasoning mechanism,the first stage case-based reasoning to analyze the main level,clear nature of the problem,type,degree and character as the main content;the second stage case reasoning takes first order case reasoning result as basis then,the case reasoning,gives to making policy holding out being that purpose is in progress to out a decision-making suggestion once again.Secondly,in many cases the design of the library,to serve two-stage case-based reasoning process,the design of the four case libraries:First,property type case library,is a static case base can be modified,the effect is to performance differences between actual case and plan case of the qualitative distinction,indicate difference type attribute;Second,hierarchic quantization case library,is a static case base can be modified,the effect is to performance differences between actual case and plan case the quantitative distinction between the scope,indicate degree,size that the type issues in some difference etc.Three are that decision-making supports case library,is a static case base can be modified,the effect is similar enumeration all possible decision-makings content,indicate the decision-making that field expert possibility carries out;Four are decision match case library,is a self-study and dynamic case library,the effect is the library recording history decision-making case,is used to gain the decision-making scheme specifically for current reality achievement case is similar,to provide the support making policy,to learn composing in reply the case accumulating the new decision-making at the same time.The method is based on real business needs for research and development obtained after the conclusion,the paper shows through examples of the technology industry has a good adaptability,practicality and effectiveness.
基金Supported by National Natural Science Foundation of China(5 990 60 14 )
文摘The double fire two stage method of underground coal gasification was suggested. On the basis of material balance, the ideal gasification parameters were calculated, and the field test process was briefly introduced. In addition, the cause for a middle to a high heat value of water gas was described. And the reasonableness and feasiblity of the method was proved, showing that the double fire two stage gasification is an important technique for commercialized production.
基金Supported by Lilavati Hospital and Research Centre
文摘Gall bladder torsion(GBT) is a relatively uncommon entity and rarely diagnosed preoperatively. A constant factor in all occurrences of GBT is a freely mobile gall bladder due to congenital or acquired anomalies. GBT is commonly observed in elderly white females. We report a 77-year-old, Caucasian lady who was originally diagnosed as gall bladder perforation but was eventually found with a two staged torsion of the gall bladder with twisting of the Riedel's lobe(part of tongue like projection of liver segment 4A). This together, has not been reported in literature, to the best of our knowledge. We performed laparoscopic cholecystectomy and she had an uneventful postoperative period. GBT may create a diagnostic dilemma in the context of acute cholecystitis. Timely diagnosis and intervention is necessary, with extra care while operating as the anatomy is generally distorted. The fundus first approach can be useful due to altered anatomy in the region of Calot's triangle. Laparoscopic cholecystectomy has the benefit of early recovery.
文摘Non-response is a regular occurrence in Sample Surveys. Developing estimators when non-response exists may result in large biases when estimating population parameters. In this paper, a finite population mean is estimated when non-response exists randomly under two stage cluster sampling with replacement. It is assumed that non-response arises in the survey variable in the second stage of cluster sampling. Weighting method of compensating for non-response is applied. Asymptotic properties of the proposed estimator of the population mean are derived. Under mild assumptions, the estimator is shown to be asymptotically consistent.
文摘We study a two stage queuing model where the server provides two stages of service one by one in succession. We consider reneging to occur when the server is unavailable during the system breakdown or vacation periods. We concentrate on deriving the steady state solutions by using supplementary variable technique and calculate the mean queue length and mean waiting time. Further some special cases are also discussed and numerical examples are presented.
基金Supported by the Ministerial Level Research Project of China(D2220112901)
文摘A two stage turbocharging control system was proposed,in which the pressure regulator valve with a close-loop pressure adjusting function instead of a high speed on-off solenoid valve,is used as a driving mechanism of waste gate.A digital-analog（DA）conversion circuit based on pulse width modulation（PWM）generates one analog voltage signal required by the pressure regulating valve control.The principle of the DA conversion circuit was analyzed,meanwhile,the performance of the conversion circuit was improved by adopting a speed-up capacitor,which helps to increase the stability and responsiveness of the control voltage generated by the conversion circuit;the structure parameters of the circuit was optimized by simulation.After the optimization,the ripple wave of circuit output voltage was kept within16mV under the 12bit conversion accuracy,the conversion time of the circuit could be reduced to 4ms.The engine bench test show that the turbocharging boost pressure control system which adopted the circuit had a rather good stable control accuracy（the steady state within 0.8%）and dynamic response（the regulation time is less than 4s）.
文摘The full bridge zero voltage zero current switching （ FB-ZVZCS ） , which could adjust the output power by keeping the duty ratio of lagging leg constant and changing the duty ratio of leading leg, was a common circuit of soft switching arc welding inverter power source. However, when the duty ratio of leading leg was reduced to zero, the output power stayed the constant value instead of becoming zero. The working status and waveforms of some major parameters were studied in this paper while the duty ratio of leading leg was zero. It was concluded that the minimum output power of soft switching inverter was related to the charging voltage of paraUel capacitors, and the output power also could be reduced by reducing the duty ratio of lagging leg. A novel two-stage continuous PWM control method that could switch working-mode between full bridge and half bridge was put forward in this paper. This kind of control method could further reduce the output power of soft switching inverter in order to meet the requirement of low heat input of sheet metal welding.
文摘The paper deals with the comparative analysis of the performance of cooling and heating systems operating with NH3 （ammonia） or CO2 （carbon dioxide）, both natural refrigerants. The study is based on the exergetic analysis that points out the location and the magnitude of a system malfunction. Both systems, with NH3 or CO2 operate in two stages. The exergetic analysis gives the direction of the structural optimization. The exergetic analysis has shown that the best structural schematic is not the same for the two agents. The exergetic analysis points out that the largest exergy destruction in the CO2 cycle is due to the throttling process and offers solutions to diminish it.
基金Supported by Kaohsiung Municipal Min-Seng Hospital(KMSH 9702)
文摘AIM: To assess the cost-effectiveness of two populationbased hepatocellular carcinoma(HCC) screening programs, two-stage biomarker-ultrasound method and mass screening using abdominal ultrasonography(AUS).METHODS: In this study, we applied a Markov decision model with a societal perspective and a lifetime horizon for the general population-based cohorts in an area with high HCC incidence, such as Taiwan. The accuracy of biomarkers and ultrasonography was estimated from published meta-analyses. The costs of surveillance, diagnosis, and treatment were based on a combination of published literature, Medicare payments, and medical expenditure at the National Taiwan University Hospital. The main outcome measure was cost per lifeyear gained with a 3% annual discount rate. RESULTS: The results show that the mass screening using AUS was associated with an incremental costeffectiveness ratio of USD39825 per life-year gained, whereas two-stage screening was associated with an incremental cost-effectiveness ratio of USD49733 per life-year gained, as compared with no screening. Screening programs with an initial screening age of 50 years old and biennial screening interval were the most cost-effective. These findings were sensitive to the costs of screening tools and the specificity of biomarker screening.CONCLUSION: Mass screening using AUS is more cost effective than two-stage biomarker-ultrasound screening. The most optimal strategy is an initial screening age at 50 years old with a 2-year inter-screening interval.
基金supported by the National Science and Technology Major Project (No. 2009ZX07529-004-2)the National High Technology Research and Development Program (863) of China (No. 2009AA063901)
文摘A two-stage UASB reactor was employed to remove sulfate from acrylic fiber manufacturing wastewater.Mesophilic operation（35±0.5℃） was performed with hydraulic retention time（HRT） varied between 28 and 40 hr.Mixed liquor suspended solids（MLSS） in the reactor was maintained about 8000 mg/L.The results indicated that sulfate removal was enhanced with increasing the ratio of COD/SO24-.At low COD/SO42-,the growth of the sulfate-reducing bacteria（SRB） was carbon-limited.The optimal sulfate removal efficiencies were 75% when the HRT was no less than 38 hr.Sulfidogenesis mainly happened in the sulfate-reducing stage,while methanogenesis in the methane-producing stage.Microbes in sulfate-reducing stage performed granulation better than that in methaneproducing stage.Higher extracellular polymeric substances（EPS） content in sulfate-reducing stage helped to adhere and connect the flocculent sludge particles together.SRB accounted for about 31% both in sulfate-reducing stage and methane-producing stage at COD/SO42-ratio of 0.5,while it dropped dramatically from 34% in sulfate-reducing stage to 10% in methane-producing stage corresponding to the COD/SO42-ratio of 4.7.SRB and MPA were predominant in sulfate-reducing stage and methane-producing stage respectively.
基金financially supported by the post-doctoral program of 54~(th) China Postdoctoral Science Foundation(No.2013M541255)Career Development Support Program for Young and Middle-aged Teachers of Shenyang Pharmaceutical University(No.ZQN2015034)+1 种基金the funds from Shenyang Pharmaceutical UniversityKanion Pharmaceutical Co.Ltd
文摘Poria cocos(Schw.) Wolf, an important medicinal and food fungus, is well known in East Asia. Due to growing market demand, long cultivation period, and consumption of pine trunk during cultivation, developing alternative methods for producing P. cocos and/or its active components is of interest. In the present study, the effects of different culture methods on biomass and accumulation of four triterpenoids were investigated. The ethanol extract of fermented mycelium(EFM) was orally administered to rats. Urine output and concentrations of electrolytes(Na^+, K^+, and Cl^-) were measured. Our results showed that mycelia grew better under continuous shaking culture condition(7.5 g DW·L^(-1)), and higher triterpenoid levels were accumulated in two-stage culture(112 mg·L-1, 2.03%). The optimal starting time of static culture for triterpenoid yield was 4^(th) d after shaking culture. Single administration of middle and high dose of EFM significantly increased urine output, Na^+ and Cl^- excretion, and Na^+/K^+ ratio. These results suggested that ethanol extract of cultured mycelia showed significant diuretic activity in rats and two-stage culture of P. cocos could be an alternative way to produce mycelia and triterpenoids.
基金part of the Program of "Study on Optimization and Supply-side Reliability of Oil Product Supply Chain Logistics System" funded under the National Natural Science Foundation of China, Grant Number 51874325
文摘Oil and gas pipeline networks are a key link in the coordinated development of oil and gas both upstream and downstream.To improve the reliability and safety of the oil and gas pipeline network, inspections are implemented to minimize the risk of leakage, spill and theft, as well as documenting actual incidents. In recent years, unmanned aerial vehicles have been recognized as a promising option for inspection due to their high efficiency. However, the integrated optimization of unmanned aerial vehicle inspection for oil and gas pipeline networks, including physical feasibility, the performance of mission, cooperation, real-time implementation and three-dimensional(3-D) space, is a strategic problem due to its large-scale,complexity as well as the need for efficiency. In this work, a novel mixed-integer nonlinear programming model is proposed that takes into account the constraints of the mission scenario and the safety performance of unmanned aerial vehicles. To minimize the total length of the inspection path, the model is solved by a two-stage solution method. Finally, a virtual pipeline network and a practical pipeline network are set as two examples to demonstrate the performance of the optimization schemes. Moreover, compared with the traditional genetic algorithm and simulated annealing algorithm, the self-adaptive genetic simulated annealing algorithm proposed in this paper provides strong stability.
基金financial supports by National Key R&D Program of China (No. 2016YFB1200600 and No. 2016YFB1200504)Strategic Priority Program of the Chinese Academy of Sciences (No. XDB22000000)
文摘Different artificial two-stage ageing behaviors and their effect on stress corrosion cracking （SCC） susceptibility of AI-Zn-Mg alloy have been investigated. The experimental results show that two hardness peaks present on the second-stage ageing-hardening curve when the first-stage ageing is dealt with comparatively lower temperature than the conventional one. The first peak is caused by dispersive and evenly distributed G.P. zones, while η ′phases and coarsened G.P. zones contribute to the second peak. Tensile strength of experimental alloy raises 9.6% （33.2 MPa） and SCC susceptibility decreases 38.9% by applying the second peak ageing regime instead of conventional T73. AI-Zn-Mg alloy obtains high strength and SCC resistance due to its finely dispersive matrix precipitates （MPts）, coarsened and discontinuous grain boundary precipitates （GBPs）, as well as the narrow precipitate free zone （PFZ） in the second peak ageing condition. 2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.
