生育生活质量量表(Fertility Quality of Life Questionnaire,FertiQoL)是不孕不育人群生活质量测量的特异性量表。生育生活质量下降会影响不孕不育人群的治疗积极性及治疗依从性,从而影响患者的助孕结局。大量研究表明,不孕不育人群生...生育生活质量量表(Fertility Quality of Life Questionnaire,FertiQoL)是不孕不育人群生活质量测量的特异性量表。生育生活质量下降会影响不孕不育人群的治疗积极性及治疗依从性,从而影响患者的助孕结局。大量研究表明,不孕不育人群生育生活质量各模块及维度均有受损,但影响因素及对不同维度的影响程度尚无统一结论。中国和国外不孕不育人群生育生活质量受损情况不同,中国患者治疗模块受损更严重,国外患者核心模块受损更严重。社会支持、心理韧性是生育生活质量的保护因素,焦虑、抑郁、述情障碍、生育压力、病耻感则与生育生活质量呈负相关。除此之外,性别、年龄、居住地、受教育程度及不孕年限等一般特征也是不孕不育人群生育生活质量的重要影响因素。但目前对于提高患者生育生活质量的干预措施及干预后临床妊娠率是否得到提升的研究尚不充分。展开更多
Paris law can reflect the failure mechanism of materials and is usually used to be a method to predict fatigue life or residual fatigue life.But the variable which can represent the health of machine is hardly measure...Paris law can reflect the failure mechanism of materials and is usually used to be a method to predict fatigue life or residual fatigue life.But the variable which can represent the health of machine is hardly measured on line.To a degree,the difficulty of on-line application restricts the scope of application of Paris law.The relationship between characteristic values of vibration signals and the variable in the Paris equation which can describe the health of machine is investigated by taking ball bearings as investigative objects.Based on 6205 deep groove ball bearings as a living example,historical lives and vibration signals are analyzed.The feasibility of describing that variable in the Paris equation by the characteristic value of vibration signals is inspected.After that vibration signals decomposed by empirical mode decomposition（EMD）,root mean square（RMS） of intrinsic mode function（IMF） involving fault characteristic frequency has a consistent trend with the diameter of flaws.Based on the trend,two improved Paris models are proposed and the scope of application of them is inspected.These two Paris Models are validated by fatigue residual life data from tests of rolling element bearings and vibration signals monitored in the process of operation of rolling element bearings.It shows that the first improved Paris Model is simple and plain and it can be easily applied in actual conditions.The trend of the fatigue residual life predicted by the second improved Paris model is close to the actual conditions and the result of the prediction is slightly greater than the truth.In conclusion,after the appearance of detectable faults,these improved models based on RMS can predict residual fatigue life on line and a new approach to predict residual fatigue life of ball bearings on line without disturbing the machine running is provided.展开更多
Fine root turnover plays a key role in carbon （C） budgets and nutrients cycles in forest ecosystems. However, the difference between branch-order-based and diameter-based approaches in estimating fine root turnover ...Fine root turnover plays a key role in carbon （C） budgets and nutrients cycles in forest ecosystems. However, the difference between branch-order-based and diameter-based approaches in estimating fine root turnover is still unclear. We studied root biomass turnover based on multiplying root standing biomass by turnover rate （inverse of median root longevity） in two Chinese temperate tree species, Fraxinus mand- shurica Rupr. and Larix gmelinii Rupr. The minirhizotron （MR） tech- nique was used to estimate longevities for first and second order roots, and total roots （R,o,al） apparent on the MR tube surface. The correspond- ing biomass for each root group was estimated by soil monolith. The difference in biomass turnover between Rtotal and the sum of the first and second order roots was used to represent the discrepancy between di- ameter- and order-based approaches. First order roots had shorter life spans and higher biomass turnover rates than the second order roots in both species. Biomass turnover estimated by the order-based method for F. mandshurica and L. gmelinii were 155.4 g.m2.aland 158.9 g.m2.a-1, respectively, in comparison with 99.5 g.m^-2-a^-1 and 117.7 g.m^-2.a^-1 estimated by the diameter-based method, indicating that the diameter-based approach underestimated biomass turnover. The most probable reason was that the order-based method enhanced separation of the heterogeneous root population into relatively homogenous root groups with varying turnover rates. We conclude that separating fine root pool into different branch orders can improve the accuracy of estimates for fine root turnover, as well as the understanding of the belowground C allocation and nutrient cycling at ecosystem level.展开更多
The blade root fatigue is one of important failure modes of turbocharger turbine for vehicle application,and the reliability and life of turbine with blade root fatigue failure mode are studied.Firstly,the stress char...The blade root fatigue is one of important failure modes of turbocharger turbine for vehicle application,and the reliability and life of turbine with blade root fatigue failure mode are studied.Firstly,the stress characteristics of turbine are analyzed,and based on the operating profile of turbocharger corresponding to the endurance test of engine,the stress spectrum of turbine with blade root fatigue failure mode is studied with the simulation method.Then,with the number of endurance test profile cycle as the life parameter,the reliability model and failure rate model of turbine with blade root fatigue failure mode are derived respectively. Finally,the rules that the reliability and failure rate of turbine with the blade root fatigue failure mode changes as life parameters are studied,and the life probabilistic characteristics of turbine are also studied.展开更多
文摘生育生活质量量表(Fertility Quality of Life Questionnaire,FertiQoL)是不孕不育人群生活质量测量的特异性量表。生育生活质量下降会影响不孕不育人群的治疗积极性及治疗依从性,从而影响患者的助孕结局。大量研究表明,不孕不育人群生育生活质量各模块及维度均有受损,但影响因素及对不同维度的影响程度尚无统一结论。中国和国外不孕不育人群生育生活质量受损情况不同,中国患者治疗模块受损更严重,国外患者核心模块受损更严重。社会支持、心理韧性是生育生活质量的保护因素,焦虑、抑郁、述情障碍、生育压力、病耻感则与生育生活质量呈负相关。除此之外,性别、年龄、居住地、受教育程度及不孕年限等一般特征也是不孕不育人群生育生活质量的重要影响因素。但目前对于提高患者生育生活质量的干预措施及干预后临床妊娠率是否得到提升的研究尚不充分。
基金supported by National Natural Science Foundation of China (Grant No. 50705096)National Science and Technology Major Project of China(Grant No. 2009zx04014-014)
文摘Paris law can reflect the failure mechanism of materials and is usually used to be a method to predict fatigue life or residual fatigue life.But the variable which can represent the health of machine is hardly measured on line.To a degree,the difficulty of on-line application restricts the scope of application of Paris law.The relationship between characteristic values of vibration signals and the variable in the Paris equation which can describe the health of machine is investigated by taking ball bearings as investigative objects.Based on 6205 deep groove ball bearings as a living example,historical lives and vibration signals are analyzed.The feasibility of describing that variable in the Paris equation by the characteristic value of vibration signals is inspected.After that vibration signals decomposed by empirical mode decomposition（EMD）,root mean square（RMS） of intrinsic mode function（IMF） involving fault characteristic frequency has a consistent trend with the diameter of flaws.Based on the trend,two improved Paris models are proposed and the scope of application of them is inspected.These two Paris Models are validated by fatigue residual life data from tests of rolling element bearings and vibration signals monitored in the process of operation of rolling element bearings.It shows that the first improved Paris Model is simple and plain and it can be easily applied in actual conditions.The trend of the fatigue residual life predicted by the second improved Paris model is close to the actual conditions and the result of the prediction is slightly greater than the truth.In conclusion,after the appearance of detectable faults,these improved models based on RMS can predict residual fatigue life on line and a new approach to predict residual fatigue life of ball bearings on line without disturbing the machine running is provided.
基金supported by the grants of the National Natural Science Foundation of China (No. 31100470)the Ministry of Science and Technology of China (No. 2011BAD37B02-2)
文摘Fine root turnover plays a key role in carbon （C） budgets and nutrients cycles in forest ecosystems. However, the difference between branch-order-based and diameter-based approaches in estimating fine root turnover is still unclear. We studied root biomass turnover based on multiplying root standing biomass by turnover rate （inverse of median root longevity） in two Chinese temperate tree species, Fraxinus mand- shurica Rupr. and Larix gmelinii Rupr. The minirhizotron （MR） tech- nique was used to estimate longevities for first and second order roots, and total roots （R,o,al） apparent on the MR tube surface. The correspond- ing biomass for each root group was estimated by soil monolith. The difference in biomass turnover between Rtotal and the sum of the first and second order roots was used to represent the discrepancy between di- ameter- and order-based approaches. First order roots had shorter life spans and higher biomass turnover rates than the second order roots in both species. Biomass turnover estimated by the order-based method for F. mandshurica and L. gmelinii were 155.4 g.m2.aland 158.9 g.m2.a-1, respectively, in comparison with 99.5 g.m^-2-a^-1 and 117.7 g.m^-2.a^-1 estimated by the diameter-based method, indicating that the diameter-based approach underestimated biomass turnover. The most probable reason was that the order-based method enhanced separation of the heterogeneous root population into relatively homogenous root groups with varying turnover rates. We conclude that separating fine root pool into different branch orders can improve the accuracy of estimates for fine root turnover, as well as the understanding of the belowground C allocation and nutrient cycling at ecosystem level.
基金National Natural Science Foundation of China(No.51375465)
文摘The blade root fatigue is one of important failure modes of turbocharger turbine for vehicle application,and the reliability and life of turbine with blade root fatigue failure mode are studied.Firstly,the stress characteristics of turbine are analyzed,and based on the operating profile of turbocharger corresponding to the endurance test of engine,the stress spectrum of turbine with blade root fatigue failure mode is studied with the simulation method.Then,with the number of endurance test profile cycle as the life parameter,the reliability model and failure rate model of turbine with blade root fatigue failure mode are derived respectively. Finally,the rules that the reliability and failure rate of turbine with the blade root fatigue failure mode changes as life parameters are studied,and the life probabilistic characteristics of turbine are also studied.
