The factors that influence the properties of spandex/cotton core-spun yarns are introduced. The pre-drafting multiple of spandex is an important parameter that influences the yarn properties such as elasticity,breakin...The factors that influence the properties of spandex/cotton core-spun yarns are introduced. The pre-drafting multiple of spandex is an important parameter that influences the yarn properties such as elasticity,breaking force, breaking elongation and costs. The experiment with different pre-drafting multiple isdesigned. The effects of pre-drafting multiple on yarn properties are evaluated by fuzzy mathematical decision.3.3 is the optimum pre-drafting multiple for 14.6tex +40D spandex/cotton core-spun yarns. At this multiple,the spandex content is proper and the spandex core is less prone to breakage. The cotton fibers wrap spandex more closely and transfer more frequently between inside and outside.展开更多
Once operating trains are disabled on the railway lines,an efficient manner is to utilize the train for train rescue.Owning to the different train and coupler types,it is difficult to formulate uniform regulations for...Once operating trains are disabled on the railway lines,an efficient manner is to utilize the train for train rescue.Owning to the different train and coupler types,it is difficult to formulate uniform regulations for train to train rescue.In this paper,the longitudinal train dynamics of electric multiple units under rescue were analyzed by field and laboratory tests.The angling behavior of the brakinginduced coupler under compressed in-train forces was analyzed.A dynamic model for the train and draft gear system was developed considering accurate boundary limitations and braking characteristics.The safety indices and their limits for the coupled rescue train were defined.Thedynamic evaluations of different train to train rescue scenarios were analyzed.It is indicated that the coupler vertical rotation occurs during the emergency braking applied by the assisting train.The vertical force components of intrain forces lead to the carbody pitch behavior and even cause local destructions to the coupler system.The carbody pitch motion can arise the inference of in-train devices.Based on the safety evaluation of train and coupler system,the regulations for typical train to train rescue scenarios were formulated.展开更多
文摘The factors that influence the properties of spandex/cotton core-spun yarns are introduced. The pre-drafting multiple of spandex is an important parameter that influences the yarn properties such as elasticity,breaking force, breaking elongation and costs. The experiment with different pre-drafting multiple isdesigned. The effects of pre-drafting multiple on yarn properties are evaluated by fuzzy mathematical decision.3.3 is the optimum pre-drafting multiple for 14.6tex +40D spandex/cotton core-spun yarns. At this multiple,the spandex content is proper and the spandex core is less prone to breakage. The cotton fibers wrap spandex more closely and transfer more frequently between inside and outside.
基金supported by the National Natural Science Foundation of China [No.U1334206]the National Key R&D Program of China [No.2016YFB1200500]
文摘Once operating trains are disabled on the railway lines,an efficient manner is to utilize the train for train rescue.Owning to the different train and coupler types,it is difficult to formulate uniform regulations for train to train rescue.In this paper,the longitudinal train dynamics of electric multiple units under rescue were analyzed by field and laboratory tests.The angling behavior of the brakinginduced coupler under compressed in-train forces was analyzed.A dynamic model for the train and draft gear system was developed considering accurate boundary limitations and braking characteristics.The safety indices and their limits for the coupled rescue train were defined.Thedynamic evaluations of different train to train rescue scenarios were analyzed.It is indicated that the coupler vertical rotation occurs during the emergency braking applied by the assisting train.The vertical force components of intrain forces lead to the carbody pitch behavior and even cause local destructions to the coupler system.The carbody pitch motion can arise the inference of in-train devices.Based on the safety evaluation of train and coupler system,the regulations for typical train to train rescue scenarios were formulated.
