In terms of single-atom induced dipole moment by Lewenstein model, we present the macroscopic high-order harmonic generation from mixed He and Ne gases with different mixture ratios by solving three-dimensional Maxwel...In terms of single-atom induced dipole moment by Lewenstein model, we present the macroscopic high-order harmonic generation from mixed He and Ne gases with different mixture ratios by solving three-dimensional Maxwell＇s equation of harmonic field. And then we show the validity of mixture formulation by Wagner et al. [Phys. Rev. A 76 （2007） 061403（R）] in macroscopic response level. Finally, using/east squares fitting we retrieve the electron return time of short trajectory by formulation in Kanai et al. [Phys. Rev. Lett. 98 （2007） 153904] when the gas jet is put after the laser focus.展开更多
Effects of reduced frequency, stop angle, and pause duration have been studied on a thin supercritical airfoil undergoing a pitch-pause-return motion, which is one of the classic maneuvers introduced by the AIAA Fluid...Effects of reduced frequency, stop angle, and pause duration have been studied on a thin supercritical airfoil undergoing a pitch-pause-return motion, which is one of the classic maneuvers introduced by the AIAA Fluid Dynamics Technical Committee. Experiments were conducted in a low-speed wind tunnel at both a constant mean angle of attack and an oscillation amplitude with a reduced frequency ranging from 0.01 to 0.12. The desired stop angles of the airfoil were set to occur during the upstroke motion. The unsteady pressure distribution on the airfoil was measured for below, near, and beyond static stall conditions. Results showed that the reduced frequency and stop angle were the dominant contributors to the time lag in the flowfield. For stop angles in both belowand post-stall regions, the time for the flowfield to reach its steady state conditions, known as the time lag, decreased as the reduced frequency was increased. However, in the static-stall region and for a certain value of reduced frequency, a resonance phenomenon was observed, and a minimum time lag was achieved. The pressure distribution in this condition was shown to be highly influenced by this phenomenon.展开更多
Qiyechangbai and Hadacongl were used to study the relationship of the leaf age of overwinter to bolting and, returning green by the difference of sowing time. The results showed that the earlier the seeds were sown, t...Qiyechangbai and Hadacongl were used to study the relationship of the leaf age of overwinter to bolting and, returning green by the difference of sowing time. The results showed that the earlier the seeds were sown, the older leaf age of overwinter was, the higher the rates of returning green and bolting rate were, the earlier the bolting time was. The leaf age of overwinter of Qiyechangbai sown August 31 to September 14 was 2.1-3.1 leaves and the rate of returning green was 86.5%-92.1%, while the leaf age of overwinter of Hadacongl sown September 7 to September 14 was 2.3-2.7 leaves and the rate of returning green was 88.5%-93.8%, both varieties didn＇t bolt. In addition, in the same sowing time, the bolting rate of Hadacong I was higher than that of Qiyechangbai slightly.展开更多
我国每年生产大量的作物秸秆,不加处理或处理不当,会严重威胁水体或大气环境质量。秸秆还田是当前解决作物秸秆田间焚烧或无序堆放威胁环境质量的最主要方法。秸秆还田按目的可分为两种方式:以处置秸秆为目的的处置化原位还田和以消除...我国每年生产大量的作物秸秆,不加处理或处理不当,会严重威胁水体或大气环境质量。秸秆还田是当前解决作物秸秆田间焚烧或无序堆放威胁环境质量的最主要方法。秸秆还田按目的可分为两种方式:以处置秸秆为目的的处置化原位还田和以消除作物生长障碍因素为目的的消障化异地还田。无论何种秸秆还田方式均未利用秸秆生物能,虽在一定程度上可以提高土壤有机质含量,但作用有限,且无显著的时间累积效应。秸秆沼气化利用了秸秆生物能,但因产气不稳定,沼渣、沼液处理难等因素,推广应用难度大。笔者提出了一种能够在同一时间和空间,实现秸秆改土和产能等多重目标的秸秆处理方式,称作“秸秆改土产能时空一体化处理”方法(space-time Integration of Soil improvement and Energy production by using Straw,ISES),即就近集中秸秆于需要改良的土壤,使秸秆施用量达到5%土重以上,与土壤充分混匀,在淹水条件下,密封培养,收集厌氧发酵产生的沼气用作家庭燃料或作它用。ISES处理可跨肥力等级提升土壤有机质含量,产气量及气体中CH4浓度与沼气发酵相当,且不需要处理沼液和沼渣,可服务于改土、产能和固碳等多重目标。加强对ISES系统碳转化和CH4产生过程及其产气率和CH4浓度影响因素的研究,评估ISES处理过程及处理后的环境效应,对于优化处理工艺,明确可采用ISES处理的土壤类型、适宜的处理时间,降低ISES处理的环境效应,制订安全生产措施,预测经济可行性都是十分必要的。展开更多
AIM To systemically review all studies reporting return to sport following tibial plateau fracture, in order to provide information on return rates and times to sport, and to assess variations in sporting outcome for ...AIM To systemically review all studies reporting return to sport following tibial plateau fracture, in order to provide information on return rates and times to sport, and to assess variations in sporting outcome for different treatment methods.METHODS A systematic search of CINAHAL, Cochrane, EMBASE, Google Scholar, MEDLINE, PEDro, Scopus, SPORTDiscus and Web of Science was performed in January 2017 using the keywords "tibial", "plateau", "fractures", "knee", "athletes", "sports", "non-operative", "conservative", "operative", "return to sport". All studies which recorded return rates and times to sport following tibial plateau fractures were included. RESULTS Twenty-seven studies were included: 1 was a randomised controlled trial, 7 were prospective cohort studies, 16 were retrospective cohort studies, 3 were case series. One study reported on the outcome of conservative management(n = 3); 27 reported on the outcome of surgical management(n = 917). Nine studies reported on Open Reduction Internal Fixation(ORIF)(n = 193), 11 on Arthroscopic-Assisted Reduction Internal Fixation(ARIF)(n = 253) and 7 on Frame-Assisted Fixation(FRAME)(n = 262). All studies recorded "return to sport"rates. Only one study recorded a "return to sport" time. The return rate to sport for the total cohort was 70%. For the conservatively-managed fractures, the return rate was 100%. For the surgically-managed fractures, the return rate was 70%. For fractures managed with ORIF, the return rate was 60%. For fractures managed with ARIF, the return rate was 83%. For fractures managed with FRAME was 52%. The return rate for ARIF was found to be significantly greater than that for ORIF(OR 3.22, 95%CI: 2.09-4.97, P < 0.001) and for FRAME(OR 4.33, 95%CI: 2.89-6.50, P < 0.001). No difference was found between the return rates for ORIF and FRAME(OR 1.35, 95%CI: 0.92-1.96, P = 0.122). The recorded return time was 6.9 mo(median), from a study reporting on ORIF.CONCLUSION Return rates to sport for tibial plateau fractures remain limited compared to other fractures. ARIF provides the best return rates. There is limited data regarding return times to sport. Further research is required to determine return times to sport, and to improve return rates to sport, through treatment and rehabilitation optimisation.展开更多
Using China Health and Nutrition Survey(CHNS) data between 1989 and 2011, this paper measures the returns to education in China based on the Mincer earnings function and reaches the following findings through an analy...Using China Health and Nutrition Survey(CHNS) data between 1989 and 2011, this paper measures the returns to education in China based on the Mincer earnings function and reaches the following findings through an analysis of the tendency of continuous variations over a long timeframe: returns to education are on the rise within the range of samples both under relative and absolute scenarios; returns to different levels of education are characterized by increasing marginal return; no significant difference exists between the returns to junior middle school and the returns to primary school education. Further discussions consider that the requirements of job positions for the overall competence of personnel, differentiated decline of corporate demand for recruitment, lack of an evaluation system in the labor market, information asymmetry in the job market, the development strategy adopted in a particular stage of history and the current slow progress of economic transition have jointly led to the underemployment of college graduates and the great enthusiasm of parents investing in higher education for their children. Conclusions of this paper not only have important practical relevance to the ongoing implementation of China's innovation-driven development strategy, but offer inspirations for the new round of educational reform as well.展开更多
The Economic Production Quantity (EPQ) model is commonly used by practitioners in the fields of production and inventory management to assist them in making decision on production lot size. The common assumptions in t...The Economic Production Quantity (EPQ) model is commonly used by practitioners in the fields of production and inventory management to assist them in making decision on production lot size. The common assumptions in this model are that all units produced are perfect and shortages are not allowed. But, in real situation the defective items will be produced in each cycle of production and shortages and scrap are possible. These assumptions will underestimate the actual required quantity. Hence, the defective items can not be ignored in the production process. Rework process is necessary to convert those defective into finished goods. This study proposes EPQ model that incorporates both imperfect production quality and falsely not screening out a proportion of defects, thereby passing them on to customers, resulting in defect sales returns. To active this objective a suitable mathematical model is developed and the optimal production lot size which minimizes the total cost is derived. An illustrative example is provided and numerically verified. The validation of result in this model was coded in Microsoft Visual Basic 6.0.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No. 10674112the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No. 20096203110001+1 种基金the Foundation of Center of Theoretical Nuclear Physics of National Laboratory of Heavy Ion Accelerator of LanzhouFoundation of Northwest Normal University under Grant No. NWNUKJCXGC-03-62
文摘In terms of single-atom induced dipole moment by Lewenstein model, we present the macroscopic high-order harmonic generation from mixed He and Ne gases with different mixture ratios by solving three-dimensional Maxwell＇s equation of harmonic field. And then we show the validity of mixture formulation by Wagner et al. [Phys. Rev. A 76 （2007） 061403（R）] in macroscopic response level. Finally, using/east squares fitting we retrieve the electron return time of short trajectory by formulation in Kanai et al. [Phys. Rev. Lett. 98 （2007） 153904] when the gas jet is put after the laser focus.
文摘Effects of reduced frequency, stop angle, and pause duration have been studied on a thin supercritical airfoil undergoing a pitch-pause-return motion, which is one of the classic maneuvers introduced by the AIAA Fluid Dynamics Technical Committee. Experiments were conducted in a low-speed wind tunnel at both a constant mean angle of attack and an oscillation amplitude with a reduced frequency ranging from 0.01 to 0.12. The desired stop angles of the airfoil were set to occur during the upstroke motion. The unsteady pressure distribution on the airfoil was measured for below, near, and beyond static stall conditions. Results showed that the reduced frequency and stop angle were the dominant contributors to the time lag in the flowfield. For stop angles in both belowand post-stall regions, the time for the flowfield to reach its steady state conditions, known as the time lag, decreased as the reduced frequency was increased. However, in the static-stall region and for a certain value of reduced frequency, a resonance phenomenon was observed, and a minimum time lag was achieved. The pressure distribution in this condition was shown to be highly influenced by this phenomenon.
基金Supported by Science and Technology Innovation Fund of Undergraduation of Northeast Agricultural University(20060201)
文摘Qiyechangbai and Hadacongl were used to study the relationship of the leaf age of overwinter to bolting and, returning green by the difference of sowing time. The results showed that the earlier the seeds were sown, the older leaf age of overwinter was, the higher the rates of returning green and bolting rate were, the earlier the bolting time was. The leaf age of overwinter of Qiyechangbai sown August 31 to September 14 was 2.1-3.1 leaves and the rate of returning green was 86.5%-92.1%, while the leaf age of overwinter of Hadacongl sown September 7 to September 14 was 2.3-2.7 leaves and the rate of returning green was 88.5%-93.8%, both varieties didn＇t bolt. In addition, in the same sowing time, the bolting rate of Hadacong I was higher than that of Qiyechangbai slightly.
文摘我国每年生产大量的作物秸秆,不加处理或处理不当,会严重威胁水体或大气环境质量。秸秆还田是当前解决作物秸秆田间焚烧或无序堆放威胁环境质量的最主要方法。秸秆还田按目的可分为两种方式:以处置秸秆为目的的处置化原位还田和以消除作物生长障碍因素为目的的消障化异地还田。无论何种秸秆还田方式均未利用秸秆生物能,虽在一定程度上可以提高土壤有机质含量,但作用有限,且无显著的时间累积效应。秸秆沼气化利用了秸秆生物能,但因产气不稳定,沼渣、沼液处理难等因素,推广应用难度大。笔者提出了一种能够在同一时间和空间,实现秸秆改土和产能等多重目标的秸秆处理方式,称作“秸秆改土产能时空一体化处理”方法(space-time Integration of Soil improvement and Energy production by using Straw,ISES),即就近集中秸秆于需要改良的土壤,使秸秆施用量达到5%土重以上,与土壤充分混匀,在淹水条件下,密封培养,收集厌氧发酵产生的沼气用作家庭燃料或作它用。ISES处理可跨肥力等级提升土壤有机质含量,产气量及气体中CH4浓度与沼气发酵相当,且不需要处理沼液和沼渣,可服务于改土、产能和固碳等多重目标。加强对ISES系统碳转化和CH4产生过程及其产气率和CH4浓度影响因素的研究,评估ISES处理过程及处理后的环境效应,对于优化处理工艺,明确可采用ISES处理的土壤类型、适宜的处理时间,降低ISES处理的环境效应,制订安全生产措施,预测经济可行性都是十分必要的。
文摘AIM To systemically review all studies reporting return to sport following tibial plateau fracture, in order to provide information on return rates and times to sport, and to assess variations in sporting outcome for different treatment methods.METHODS A systematic search of CINAHAL, Cochrane, EMBASE, Google Scholar, MEDLINE, PEDro, Scopus, SPORTDiscus and Web of Science was performed in January 2017 using the keywords "tibial", "plateau", "fractures", "knee", "athletes", "sports", "non-operative", "conservative", "operative", "return to sport". All studies which recorded return rates and times to sport following tibial plateau fractures were included. RESULTS Twenty-seven studies were included: 1 was a randomised controlled trial, 7 were prospective cohort studies, 16 were retrospective cohort studies, 3 were case series. One study reported on the outcome of conservative management(n = 3); 27 reported on the outcome of surgical management(n = 917). Nine studies reported on Open Reduction Internal Fixation(ORIF)(n = 193), 11 on Arthroscopic-Assisted Reduction Internal Fixation(ARIF)(n = 253) and 7 on Frame-Assisted Fixation(FRAME)(n = 262). All studies recorded "return to sport"rates. Only one study recorded a "return to sport" time. The return rate to sport for the total cohort was 70%. For the conservatively-managed fractures, the return rate was 100%. For the surgically-managed fractures, the return rate was 70%. For fractures managed with ORIF, the return rate was 60%. For fractures managed with ARIF, the return rate was 83%. For fractures managed with FRAME was 52%. The return rate for ARIF was found to be significantly greater than that for ORIF(OR 3.22, 95%CI: 2.09-4.97, P < 0.001) and for FRAME(OR 4.33, 95%CI: 2.89-6.50, P < 0.001). No difference was found between the return rates for ORIF and FRAME(OR 1.35, 95%CI: 0.92-1.96, P = 0.122). The recorded return time was 6.9 mo(median), from a study reporting on ORIF.CONCLUSION Return rates to sport for tibial plateau fractures remain limited compared to other fractures. ARIF provides the best return rates. There is limited data regarding return times to sport. Further research is required to determine return times to sport, and to improve return rates to sport, through treatment and rehabilitation optimisation.
文摘Using China Health and Nutrition Survey(CHNS) data between 1989 and 2011, this paper measures the returns to education in China based on the Mincer earnings function and reaches the following findings through an analysis of the tendency of continuous variations over a long timeframe: returns to education are on the rise within the range of samples both under relative and absolute scenarios; returns to different levels of education are characterized by increasing marginal return; no significant difference exists between the returns to junior middle school and the returns to primary school education. Further discussions consider that the requirements of job positions for the overall competence of personnel, differentiated decline of corporate demand for recruitment, lack of an evaluation system in the labor market, information asymmetry in the job market, the development strategy adopted in a particular stage of history and the current slow progress of economic transition have jointly led to the underemployment of college graduates and the great enthusiasm of parents investing in higher education for their children. Conclusions of this paper not only have important practical relevance to the ongoing implementation of China's innovation-driven development strategy, but offer inspirations for the new round of educational reform as well.
文摘The Economic Production Quantity (EPQ) model is commonly used by practitioners in the fields of production and inventory management to assist them in making decision on production lot size. The common assumptions in this model are that all units produced are perfect and shortages are not allowed. But, in real situation the defective items will be produced in each cycle of production and shortages and scrap are possible. These assumptions will underestimate the actual required quantity. Hence, the defective items can not be ignored in the production process. Rework process is necessary to convert those defective into finished goods. This study proposes EPQ model that incorporates both imperfect production quality and falsely not screening out a proportion of defects, thereby passing them on to customers, resulting in defect sales returns. To active this objective a suitable mathematical model is developed and the optimal production lot size which minimizes the total cost is derived. An illustrative example is provided and numerically verified. The validation of result in this model was coded in Microsoft Visual Basic 6.0.
