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
In this paper,the Reynolds number,velocity,pressureand kinetic energy of the BCF processing hot air-floware analyzed with the help of the aero-dynamic theory,and their distributions inside the texturing tube are ob-ta...In this paper,the Reynolds number,velocity,pressureand kinetic energy of the BCF processing hot air-floware analyzed with the help of the aero-dynamic theory,and their distributions inside the texturing tube are ob-tained by pressure measuring.展开更多
Our previous study showed an association between advanced glycation end products （AGEs） and neural tube defects （NTDs）. To understand the molecular mechanisms underlying the effect of AGEs on neural tube developme...Our previous study showed an association between advanced glycation end products （AGEs） and neural tube defects （NTDs）. To understand the molecular mechanisms underlying the effect of AGEs on neural tube development, C57BL/6 female mice were fed for 4 weeks with com- mercial food containing 3% advanced glycation end product bovine serum albumin （AGE-BSA） or 3% bovine serum albumin （BSA） as a control. After mating mice, oxidative stress markers including malondialdehyde and H202 were measured at embryonic day 7.5 （E7.5） of ges- tation, and the level of intracellular reactive oxygen species （ROS） in embryonic cells was determined at E8.5. In addition to evaluating NTDs, an enzyme-linked immunosorbent assay was used to determine the effect of embryonic protein administration on the N-（carboxymethyl） lysine reactivity of acid and carboxyethyl lysine antibodies at E10.5. The results showed a remarkable increase in the incidence of NTDs at El0.5 in embryos of mice fed with AGE-BSA （no hyperglycemia） compared with control mice. Moreover, embryonic protein administration resulted in a noticeable increase in the reactivity of N-（carboxymethyl） lysine and N（ε）-（carboxyethyl） lysine antibodies. Malondialdehyde and H2O2 levels in embryonic cells were increased at E7.5, followed by increased intracellular ROS levels at E8.5. Vitamin E supplementation could partially recover these phenomena. Collectively, these results suggest that AGE-BSA could induce NTDs in the absence of hyperglycemia by an underlying mechanism that is at least partially associated with its capacity to increase embryonic oxidative stress levels.展开更多
Measurement of out-of-plane deformation is significant to understanding of the deflection mechanisms of the plate and tube structures.In this study,a new surface contouring technique with color structured light is app...Measurement of out-of-plane deformation is significant to understanding of the deflection mechanisms of the plate and tube structures.In this study,a new surface contouring technique with color structured light is applied to measure the out-of-plane deformation of structures with one-shot projection.Through color fringe recognizing,decoding and triangulation processing for the captured images corresponding to each deformation state,the feasibility of the method is testified by the measurement of elastic deflections of a flexible square plate,showing good agreement with those from the calibrated displacement driver.The plastic deformation of two alloy aluminum rectangular tubes is measured to show the technique application to surface topographic evaluation of the buckling structures with large displacements.展开更多
In this study,two sandblasting textures,namely,quartz and high-chromium(Cr)stainless steel sands,were used for sandblasting of the internal surface L80-13Cr tubing and casing.The contrastive analysis on the properties...In this study,two sandblasting textures,namely,quartz and high-chromium(Cr)stainless steel sands,were used for sandblasting of the internal surface L80-13Cr tubing and casing.The contrastive analysis on the properties of the pipes before and after abrasive blasting was conducted,including the metallographic phase detection of the internal surface,simulating accelerated corrosion tests,and residual stress tests for the pipe after abrasive blasting.Based on the analysis results,it is explained why the API standard requires that no scale appears on the internal surface of L80-13Cr and iron contamination when internal sandblasting media are applied.The results show that abrasive blasting can effectively remove scales on the internal surface of L80-13Cr tubing and casing and improve corrosion resistance.The abrasive blasting process does not produce obvious residual stress on the internal surface of the tubing and casing.Also,the de-rusting effect of stainless sand is better than that of quartz sand,and the former does not produce iron contamination.展开更多
Background: Psoriasis is a common dermatosis characterized by erythematous skin plaques and associated arthritis. Microvessels of the papillary dermis in psoriatic lesions are elongated, tortuous, and dilated, which c...Background: Psoriasis is a common dermatosis characterized by erythematous skin plaques and associated arthritis. Microvessels of the papillary dermis in psoriatic lesions are elongated, tortuous, and dilated, which contributes significantly to the proinflammatory response. Angiopoietin (Ang) 1 and 2 and their receptor, Tie2, are a family of growth factors recognized in inflammatory lesions to be critical for new blood vessel growth and maintenance, with recent studies suggesting tumor necrosis factor (TNF)-α -induced angiogenesis is in partmediated by the Tie2 receptor. The aim of this study was to evaluate the effect of anti-TNF-α therapy on angiogenic growth factor expression and on the cellular infiltrate in psoriatic lesional skin. Methods: Sixteen patients with moderate to severe psoriasis and associated psoriatic arthritis (n = 13) received infliximab infusions (3- 5 mg/kg) at baseline and at 2 and 6 weeks. Clinical assessments and skin biopsies were undertaken at baseline, and at 2 and 12 weeks. Ang 1,Ang 2, Tie2, and TNF-α messenger RNA expression were quantified by real-time polymerase chain reaction. Protein expression of vascular endothelial growth factor, Ang 2, Tie2, TNF-α , and the inflammatory infiltrate was determined using immunohistology. We conducted clinical assessments including Psoriasis Area and Severity Index, percentage body surface area, Arthritis Disease Activity Score, and Health Assessment Questionnaire. Results: At baseline expression of Ang 1/2, vascular endothelial growth factor, Tie2, and TNF-α messenger RNA and protein were greater in preinvolved skin compared with uninvolved skin (P < .05). Infliximab produced a significant reduction in protein expression of Ang 2, vascular endothelial growth factor, and Tie2 (P < .001) along with a decrease in messenger RNA expression of Ang 1 (P < .045) and Tie2 (P < .021). This was paralleled by a significant reduction in the inflammatory infiltrate scores (P < .001) and platelet-endothelial cell adhesion molecule (CD31) expression (P = .001), suggesting deactivation of endothelial cell. There was a 93% mean reduction in Psoriasis Area and Severity Index (P = .001), and a significant reduction in Disease Activity Score 28 (P = .012) and mean Health Assessment Questionnaire scores by week 12. Limitations: This study involves a small number of patients. Conclusion: These results suggest infliximab is both effective and well tolerated in severe psoriasis, resulting in deactivation of endothelium and down-regulation of growth factor and cytokine expression, leading to a decrease in the cellular infiltrate and clinical improvement in psoriasis. Furthermore, the effect of infliximab on growth factor expression, in particular Tie2, supports previous in vitro work suggesting TNF-α may be a major regulator of the Ang/Tie2 pathway.展开更多
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.
文摘In this paper,the Reynolds number,velocity,pressureand kinetic energy of the BCF processing hot air-floware analyzed with the help of the aero-dynamic theory,and their distributions inside the texturing tube are ob-tained by pressure measuring.
基金supported by the grant from Shaanxi Technology Committee of China,No.2013JM4001the China Scholarship Council(CSC)
文摘Our previous study showed an association between advanced glycation end products （AGEs） and neural tube defects （NTDs）. To understand the molecular mechanisms underlying the effect of AGEs on neural tube development, C57BL/6 female mice were fed for 4 weeks with com- mercial food containing 3% advanced glycation end product bovine serum albumin （AGE-BSA） or 3% bovine serum albumin （BSA） as a control. After mating mice, oxidative stress markers including malondialdehyde and H202 were measured at embryonic day 7.5 （E7.5） of ges- tation, and the level of intracellular reactive oxygen species （ROS） in embryonic cells was determined at E8.5. In addition to evaluating NTDs, an enzyme-linked immunosorbent assay was used to determine the effect of embryonic protein administration on the N-（carboxymethyl） lysine reactivity of acid and carboxyethyl lysine antibodies at E10.5. The results showed a remarkable increase in the incidence of NTDs at El0.5 in embryos of mice fed with AGE-BSA （no hyperglycemia） compared with control mice. Moreover, embryonic protein administration resulted in a noticeable increase in the reactivity of N-（carboxymethyl） lysine and N（ε）-（carboxyethyl） lysine antibodies. Malondialdehyde and H2O2 levels in embryonic cells were increased at E7.5, followed by increased intracellular ROS levels at E8.5. Vitamin E supplementation could partially recover these phenomena. Collectively, these results suggest that AGE-BSA could induce NTDs in the absence of hyperglycemia by an underlying mechanism that is at least partially associated with its capacity to increase embryonic oxidative stress levels.
文摘Measurement of out-of-plane deformation is significant to understanding of the deflection mechanisms of the plate and tube structures.In this study,a new surface contouring technique with color structured light is applied to measure the out-of-plane deformation of structures with one-shot projection.Through color fringe recognizing,decoding and triangulation processing for the captured images corresponding to each deformation state,the feasibility of the method is testified by the measurement of elastic deflections of a flexible square plate,showing good agreement with those from the calibrated displacement driver.The plastic deformation of two alloy aluminum rectangular tubes is measured to show the technique application to surface topographic evaluation of the buckling structures with large displacements.
文摘In this study,two sandblasting textures,namely,quartz and high-chromium(Cr)stainless steel sands,were used for sandblasting of the internal surface L80-13Cr tubing and casing.The contrastive analysis on the properties of the pipes before and after abrasive blasting was conducted,including the metallographic phase detection of the internal surface,simulating accelerated corrosion tests,and residual stress tests for the pipe after abrasive blasting.Based on the analysis results,it is explained why the API standard requires that no scale appears on the internal surface of L80-13Cr and iron contamination when internal sandblasting media are applied.The results show that abrasive blasting can effectively remove scales on the internal surface of L80-13Cr tubing and casing and improve corrosion resistance.The abrasive blasting process does not produce obvious residual stress on the internal surface of the tubing and casing.Also,the de-rusting effect of stainless sand is better than that of quartz sand,and the former does not produce iron contamination.
文摘Background: Psoriasis is a common dermatosis characterized by erythematous skin plaques and associated arthritis. Microvessels of the papillary dermis in psoriatic lesions are elongated, tortuous, and dilated, which contributes significantly to the proinflammatory response. Angiopoietin (Ang) 1 and 2 and their receptor, Tie2, are a family of growth factors recognized in inflammatory lesions to be critical for new blood vessel growth and maintenance, with recent studies suggesting tumor necrosis factor (TNF)-α -induced angiogenesis is in partmediated by the Tie2 receptor. The aim of this study was to evaluate the effect of anti-TNF-α therapy on angiogenic growth factor expression and on the cellular infiltrate in psoriatic lesional skin. Methods: Sixteen patients with moderate to severe psoriasis and associated psoriatic arthritis (n = 13) received infliximab infusions (3- 5 mg/kg) at baseline and at 2 and 6 weeks. Clinical assessments and skin biopsies were undertaken at baseline, and at 2 and 12 weeks. Ang 1,Ang 2, Tie2, and TNF-α messenger RNA expression were quantified by real-time polymerase chain reaction. Protein expression of vascular endothelial growth factor, Ang 2, Tie2, TNF-α , and the inflammatory infiltrate was determined using immunohistology. We conducted clinical assessments including Psoriasis Area and Severity Index, percentage body surface area, Arthritis Disease Activity Score, and Health Assessment Questionnaire. Results: At baseline expression of Ang 1/2, vascular endothelial growth factor, Tie2, and TNF-α messenger RNA and protein were greater in preinvolved skin compared with uninvolved skin (P < .05). Infliximab produced a significant reduction in protein expression of Ang 2, vascular endothelial growth factor, and Tie2 (P < .001) along with a decrease in messenger RNA expression of Ang 1 (P < .045) and Tie2 (P < .021). This was paralleled by a significant reduction in the inflammatory infiltrate scores (P < .001) and platelet-endothelial cell adhesion molecule (CD31) expression (P = .001), suggesting deactivation of endothelial cell. There was a 93% mean reduction in Psoriasis Area and Severity Index (P = .001), and a significant reduction in Disease Activity Score 28 (P = .012) and mean Health Assessment Questionnaire scores by week 12. Limitations: This study involves a small number of patients. Conclusion: These results suggest infliximab is both effective and well tolerated in severe psoriasis, resulting in deactivation of endothelium and down-regulation of growth factor and cytokine expression, leading to a decrease in the cellular infiltrate and clinical improvement in psoriasis. Furthermore, the effect of infliximab on growth factor expression, in particular Tie2, supports previous in vitro work suggesting TNF-α may be a major regulator of the Ang/Tie2 pathway.
