Objective:Oleic acid,a subtype of monounsaturated fatty acid(MUFA),is present in abundance in certain edible oils,particularly olive oils.Epidemiological evidence concerning dietary oleic acid intake and the long-term...Objective:Oleic acid,a subtype of monounsaturated fatty acid(MUFA),is present in abundance in certain edible oils,particularly olive oils.Epidemiological evidence concerning dietary oleic acid intake and the long-term risk of mortality is lacking.This study aimed to evaluate the associations of the dietary intake of oleic acid and other specific subtypes of MUFAs,olive oil,and other vegetable oils with cardiovascular disease(CVD)and all-cause mortality.Methods:This prospective cohort study included adults aged 40 years or older who participated in the included U.S.adults National Health and Nutrition Examination Survey(NHANES).Dietary MUFA intake was assessed via 24-h dietary recall interviews in NHANES 1999–2018,and the consumption of olive oil and other vegetable oils was assessed via a food frequency questionnaire in NHANES 2003–2006.Deaths and underlying causes of death were ascertained by linkage to the National Death Index through December 31,2019.Weighted Cox proportional hazards regression models were used to estimate the hazard ratio(HR)and 95%CIs.Results:Dietary intake of total MUFAs and oleic acid was associated with a lower risk of CVD mortality,with HRs(95%CI)of 0.62(0.39–0.99)and 0.61(0.39–0.97),respectively.Total MUFA and oleic acid intake were inversely associated with all-cause mortality;the multivariable-adjusted HRs were 0.77(95%CI:0.60–0.99)and 0.78(95%CI:0.62–0.99),respectively.There was no significant association between palmitoleic acid intake and all-cause mortality.The habitual consumption of olive oil,but not the consumption of other vegetable oils,was inversely associated with the risk of cardiovascular mortality.In the joint association analysis,the HRs(95%CI)of cardiovascular mortality were 0.36(0.19–0.69)for people who exclusively consumed olive oil,0.59(0.27–1.32)for people who consumed both olive oil and other vegetable oils,and 0.73(0.46–1.14)for people who exclusively consumed other vegetable oils compared with people who never consumed vegetable oils.Conclusions:In a U.S.nationally representative prospective cohort,higher dietary oleic acid intake and olive oil consumption were associated with a lower risk of cardiovascular mortality.展开更多
For contact dominated numerical control(NC) bending process of tube, the effect of friction on bending deformation behaviors should be focused on to achieve precision bending forming. A three dimensional(3D) elastic-p...For contact dominated numerical control(NC) bending process of tube, the effect of friction on bending deformation behaviors should be focused on to achieve precision bending forming. A three dimensional(3D) elastic-plastic finite element(FE) model of NC bending process was established under ABAQUS/Explicit platform, and its reliability was validated by the experiment. Then, numerical study on bending deformation behaviors under different frictions between tube and various dies was explored from multiple aspects such as wrinkling, wall thickness change and cross section deformation. The results show that the large friction of wiper die-tube reduces the wrinkling wave ratio η and cross section deformation degree ΔD and increases the wall thinning degree Δt. The large friction of mandrel-tube causes large η, Δt and ΔD, and the onset of wrinkling near clamp die. The large friction of pressure die-tube reduces Δt and ΔD, and the friction on this interface has little effect on η. The large friction of bending die-tube reduces η and ΔD, and the friction on this interface has little effect on Δt. The reasonable friction coefficients on wiper die-tube, mandrel-tube, pressure die-tube and bending die-tube of 21-6-9(0Cr21Ni6Mn9N) stainless steel tube in NC bending are 0.05-0.15, 0.05-0.15, 0.25-0.35 and 0.25-0.35, respectively. The results can provide a guideline for applying the friction conditions to establish the robust bending environment for stable and precise bending deformation of tube bending.展开更多
It is necessary to use the integrated stainless steel pipe having two fitting bodies without welds while train travelling at high speed. In order to form this type of integrated stainless steel pipe, the method of pre...It is necessary to use the integrated stainless steel pipe having two fitting bodies without welds while train travelling at high speed. In order to form this type of integrated stainless steel pipe, the method of preforming combined finish forming process is developed. The preforming process is characterized by flaring combined upsetting for left fitting body which is like a flange, and is characterized by tube axial compressive process under die constraint for right fitting body which is like a double-wall pipe. The finite element simulations of the processes are carried out by software package DEFORM, and the results indicate that: 1) left or right fitting body can be formed by a two-step forming process without folding and under-filling defects; 2) by using two-step forming, strain and stress in left fitting body are larger than those in right fitting body, and deformation in right fitting body is more homogenous than the deformation in left fitting body; 3) two or more preforming steps may be needed for left fitting body considering the distributions of strain and stress.展开更多
In order to explore drum instability problems of thinning spinning ultra thin-walled tubes with large diameter-to-hickness ratio, experiments of thinning spinning ultra thin-walled tubes with different clearances betw...In order to explore drum instability problems of thinning spinning ultra thin-walled tubes with large diameter-to-hickness ratio, experiments of thinning spinning ultra thin-walled tubes with different clearances between the mandrel and the tube were carried out. The phenomena of drum instability were analyzed. Drum instability mechanism was studied. The important influence of the mandrel-locked ring on stable thinning spinning was found. Besides, two important parameters, namely drum ratio and drum stiffness, were proposed to characterize the drum instability of spinning ultra thin-walled tubes with large diameter-to-thickness ratio. What's more, numerical simulations were applied to explore the influences of different clearance ratios and diameter-to-thickness ratios on the drum instability. As a result, it is found that the mandrel-locked ring is the key to the stability and precision of spinning; drum ratio can reflect the degree of the deformation of the tubes; drum stiffness is a comprehensive index to measure the influences of the tube's own parameters on the spinning instability; both the clearance ratio and diameter-thickness ratio have significant influences on the drum ratio and drum stiffness.展开更多
基金supported by the Joint Fund for New Medicine of the University of Science and Technology of China(YD9100002029).
文摘Objective:Oleic acid,a subtype of monounsaturated fatty acid(MUFA),is present in abundance in certain edible oils,particularly olive oils.Epidemiological evidence concerning dietary oleic acid intake and the long-term risk of mortality is lacking.This study aimed to evaluate the associations of the dietary intake of oleic acid and other specific subtypes of MUFAs,olive oil,and other vegetable oils with cardiovascular disease(CVD)and all-cause mortality.Methods:This prospective cohort study included adults aged 40 years or older who participated in the included U.S.adults National Health and Nutrition Examination Survey(NHANES).Dietary MUFA intake was assessed via 24-h dietary recall interviews in NHANES 1999–2018,and the consumption of olive oil and other vegetable oils was assessed via a food frequency questionnaire in NHANES 2003–2006.Deaths and underlying causes of death were ascertained by linkage to the National Death Index through December 31,2019.Weighted Cox proportional hazards regression models were used to estimate the hazard ratio(HR)and 95%CIs.Results:Dietary intake of total MUFAs and oleic acid was associated with a lower risk of CVD mortality,with HRs(95%CI)of 0.62(0.39–0.99)and 0.61(0.39–0.97),respectively.Total MUFA and oleic acid intake were inversely associated with all-cause mortality;the multivariable-adjusted HRs were 0.77(95%CI:0.60–0.99)and 0.78(95%CI:0.62–0.99),respectively.There was no significant association between palmitoleic acid intake and all-cause mortality.The habitual consumption of olive oil,but not the consumption of other vegetable oils,was inversely associated with the risk of cardiovascular mortality.In the joint association analysis,the HRs(95%CI)of cardiovascular mortality were 0.36(0.19–0.69)for people who exclusively consumed olive oil,0.59(0.27–1.32)for people who consumed both olive oil and other vegetable oils,and 0.73(0.46–1.14)for people who exclusively consumed other vegetable oils compared with people who never consumed vegetable oils.Conclusions:In a U.S.nationally representative prospective cohort,higher dietary oleic acid intake and olive oil consumption were associated with a lower risk of cardiovascular mortality.
基金Project(51164030)supported by the National Natural Science Foundation of China
文摘For contact dominated numerical control(NC) bending process of tube, the effect of friction on bending deformation behaviors should be focused on to achieve precision bending forming. A three dimensional(3D) elastic-plastic finite element(FE) model of NC bending process was established under ABAQUS/Explicit platform, and its reliability was validated by the experiment. Then, numerical study on bending deformation behaviors under different frictions between tube and various dies was explored from multiple aspects such as wrinkling, wall thickness change and cross section deformation. The results show that the large friction of wiper die-tube reduces the wrinkling wave ratio η and cross section deformation degree ΔD and increases the wall thinning degree Δt. The large friction of mandrel-tube causes large η, Δt and ΔD, and the onset of wrinkling near clamp die. The large friction of pressure die-tube reduces Δt and ΔD, and the friction on this interface has little effect on η. The large friction of bending die-tube reduces η and ΔD, and the friction on this interface has little effect on Δt. The reasonable friction coefficients on wiper die-tube, mandrel-tube, pressure die-tube and bending die-tube of 21-6-9(0Cr21Ni6Mn9N) stainless steel tube in NC bending are 0.05-0.15, 0.05-0.15, 0.25-0.35 and 0.25-0.35, respectively. The results can provide a guideline for applying the friction conditions to establish the robust bending environment for stable and precise bending deformation of tube bending.
基金Project(51305334)supported by the National Natural Science Foundation of ChinaProject(51335009)supported by the National Natural Science Foundation of China for Key Program+1 种基金Project(CXY1442(4))supported by the Science and Technology Planning Project of Xi’an,ChinaProject supported by Shaanxi Province Postdoctoral Science Research Program of China
文摘It is necessary to use the integrated stainless steel pipe having two fitting bodies without welds while train travelling at high speed. In order to form this type of integrated stainless steel pipe, the method of preforming combined finish forming process is developed. The preforming process is characterized by flaring combined upsetting for left fitting body which is like a flange, and is characterized by tube axial compressive process under die constraint for right fitting body which is like a double-wall pipe. The finite element simulations of the processes are carried out by software package DEFORM, and the results indicate that: 1) left or right fitting body can be formed by a two-step forming process without folding and under-filling defects; 2) by using two-step forming, strain and stress in left fitting body are larger than those in right fitting body, and deformation in right fitting body is more homogenous than the deformation in left fitting body; 3) two or more preforming steps may be needed for left fitting body considering the distributions of strain and stress.
基金Project(2014CB046600)supported by the National Basic Research Program of China
文摘In order to explore drum instability problems of thinning spinning ultra thin-walled tubes with large diameter-to-hickness ratio, experiments of thinning spinning ultra thin-walled tubes with different clearances between the mandrel and the tube were carried out. The phenomena of drum instability were analyzed. Drum instability mechanism was studied. The important influence of the mandrel-locked ring on stable thinning spinning was found. Besides, two important parameters, namely drum ratio and drum stiffness, were proposed to characterize the drum instability of spinning ultra thin-walled tubes with large diameter-to-thickness ratio. What's more, numerical simulations were applied to explore the influences of different clearance ratios and diameter-to-thickness ratios on the drum instability. As a result, it is found that the mandrel-locked ring is the key to the stability and precision of spinning; drum ratio can reflect the degree of the deformation of the tubes; drum stiffness is a comprehensive index to measure the influences of the tube's own parameters on the spinning instability; both the clearance ratio and diameter-thickness ratio have significant influences on the drum ratio and drum stiffness.
