Both experimental and mechanical analyses were carded out to investigate the characteristics of thickness distribution for tailor-welded tube (TWT) hydroforming with dissimilar thickness. Then, the effects of weld-s...Both experimental and mechanical analyses were carded out to investigate the characteristics of thickness distribution for tailor-welded tube (TWT) hydroforming with dissimilar thickness. Then, the effects of weld-seam position and thickness difference were also revealed. A multiple-diameter tube was formed to reveal the characteristics and the regularity of thickness distribution during TWT hydroforming. It is indicated that there are obvious fluctuations in thickness distribution though the TWTs have the same expansion ratio. The thinning ratio of thinner tube is bigger than that of thicker tube especially in the zone closed to the weld-seam. The difference in thinning ratio between two tube segments can reach 9%. Consequently, sudden and large fluctuation of thickness appears in the zone nearby the weld-seam. The difference in thinning ratio between thinner and thicker tubes enlarges as the thickness difference increases, but improves as length ratio increases. Different strain states are the main reason to induce nonuniform thickness distribution. The difference in thickness is the main reason to induce different strain states on thinner and thicker tubes.展开更多
Abstract:ools. The effective strain rate for for determining the total pressure developed during forging of a rectangular bar forging with bulging was expressed in terms of four-dimensional strain rate vector. The in...Abstract:ools. The effective strain rate for for determining the total pressure developed during forging of a rectangular bar forging with bulging was expressed in terms of four-dimensional strain rate vector. The inner-product of the vector was termwise integrated and summed. The integral mean value theorem was applied to determining the ratio of the strain rate components and the values of direction cosine of the vector and then an analytical solution of stress effective factor was obtained. The compression experiments of pure lead bar were performed to test the accuracy of the solution. The optimized results of total pressure by golden section search were compared with those of the indicator readings of the testing machine. It indicates that the optimized total pressures are 2.60%-10.14% higher than those measured. The solution is available and still an upper-bound solution.展开更多
Security relations are crucial in China-Japan relations. Since the"nationalization"of the Diaoyu Islands by Japan in 2012, mutual trust between China and Japan has been declining, and bilateral security rela...Security relations are crucial in China-Japan relations. Since the"nationalization"of the Diaoyu Islands by Japan in 2012, mutual trust between China and Japan has been declining, and bilateral security relations have reached a low point. China-Japan security relations are typified by ongoing dispute over the Diaoyu Islands, lack of mutual trust exacerbated by various actions by Japan, and the delay of China-Japan security dialogues. The evolution of China-Japan security relations derived from the Diaoyu Islands dispute is clearly beyond the scope of the dispute itself, with deep-rooted internal and external factors. In the near future,China-Japan security relations will face more challenges than opportunities. China should take measures, including enhancing mutual trust in politics and security between the two countries, to impose necessary pressure on Japan to change course, to win over neighboring countries so as to avoid pretext for Japan's intervention in regional issues,and to strengthen interpersonal communication and understanding between people of the two countries in order to stabilize security relations.展开更多
The authors’previous study identified the wave trains of intraseasonal oscillations,which are mainly in the band of 10–30 days,over the North Pacific during summer.The wave trains are zonally oriented and trapped al...The authors’previous study identified the wave trains of intraseasonal oscillations,which are mainly in the band of 10–30 days,over the North Pacific during summer.The wave trains are zonally oriented and trapped along the upper-tropospheric westerly jet,and accordingly gain energy mainly through baroclinic energy conversion.In this study,the authors investigate the distinct features of the wave trains between early summer(1 June to 7 July)and late summer(8 July to 31 August),considering that the westerly jet experiences a remarkable subseasonal variation over the North Pacific during summer—that is,the jet is much stronger in early summer than late summer.The results indicate that the wave trains are stronger in early summer compared with late summer.Further analysis suggests that,in early summer,the wave trains can obtain energy more efficiently from the basic flow;or more exactly,stronger westerlies through baroclinic energy conversion.展开更多
Purpose: Traumatic optic neuropathy (TON) is a serious complication of head trauma with the incidence rate of 0.5%-5%. The aim of this study was to investigate the therapeutic efficacy of endoscopic decompression o...Purpose: Traumatic optic neuropathy (TON) is a serious complication of head trauma with the incidence rate of 0.5%-5%. The aim of this study was to investigate the therapeutic efficacy of endoscopic decompression of the optic canal for optic nerve injuries. Methods: In this study, 11 patients treated in our hospital from January 2009 to January 2015 with the visual loss resulting from TON were retrospectively reviewed for preoperative vision, visual evoked potential (VEP) scan, surgical approach, postoperative visual acuity, complications, and follow-up results. Results: All these patients received endoscopic decompression of the optic canal. At the 3-month follow- up, the visual acuity improvement rate of the 11 patients was 45.5%. The vision acuity of 2 cases improved from hand movement to 0.08 and 0.3 after operation. Another patient's vision acuity returned to 0.05 compared to light sensation preoperatively. Two cases had finger counting before surgery but they had a vision acuity of 0.4 and light sensation respectively after surgery. However, the other 6 cases' vision did not improve after surgery. Conclusion: Endoscopic decompression of the optic canal is an effective way to cure TON. VEP could be used as an important reference for preoperative and prognosis evaluation. Operative time after trauma is only a relative condition that may affect the therapeutic effect of optic canal decompression. Poor results of this procedure may be related to the severity of the optic nerve injury.展开更多
基金Projects(51005054, 50575051) supported by the National Natural Science Foundation of ChinaProject(HIT.BRETI.2010010) supported by the Fundamental Research Funds for the Central Universities, ChinaProject(20100471025) supported by the National Science Foundation for Post-doctoral Scientists of China
文摘Both experimental and mechanical analyses were carded out to investigate the characteristics of thickness distribution for tailor-welded tube (TWT) hydroforming with dissimilar thickness. Then, the effects of weld-seam position and thickness difference were also revealed. A multiple-diameter tube was formed to reveal the characteristics and the regularity of thickness distribution during TWT hydroforming. It is indicated that there are obvious fluctuations in thickness distribution though the TWTs have the same expansion ratio. The thinning ratio of thinner tube is bigger than that of thicker tube especially in the zone closed to the weld-seam. The difference in thinning ratio between two tube segments can reach 9%. Consequently, sudden and large fluctuation of thickness appears in the zone nearby the weld-seam. The difference in thinning ratio between thinner and thicker tubes enlarges as the thickness difference increases, but improves as length ratio increases. Different strain states are the main reason to induce nonuniform thickness distribution. The difference in thickness is the main reason to induce different strain states on thinner and thicker tubes.
基金Project(51074052)supported by the National Natural Science Foundation of ChinaProject(20100470676)supported by the China Postdoctoral Science Foundation
文摘Abstract:ools. The effective strain rate for for determining the total pressure developed during forging of a rectangular bar forging with bulging was expressed in terms of four-dimensional strain rate vector. The inner-product of the vector was termwise integrated and summed. The integral mean value theorem was applied to determining the ratio of the strain rate components and the values of direction cosine of the vector and then an analytical solution of stress effective factor was obtained. The compression experiments of pure lead bar were performed to test the accuracy of the solution. The optimized results of total pressure by golden section search were compared with those of the indicator readings of the testing machine. It indicates that the optimized total pressures are 2.60%-10.14% higher than those measured. The solution is available and still an upper-bound solution.
基金a stage of the “Study on Post-war China-Japan Security Relations”(project number 3262015T76),with supplementary funding for basic research from the University of International Relations
文摘Security relations are crucial in China-Japan relations. Since the"nationalization"of the Diaoyu Islands by Japan in 2012, mutual trust between China and Japan has been declining, and bilateral security relations have reached a low point. China-Japan security relations are typified by ongoing dispute over the Diaoyu Islands, lack of mutual trust exacerbated by various actions by Japan, and the delay of China-Japan security dialogues. The evolution of China-Japan security relations derived from the Diaoyu Islands dispute is clearly beyond the scope of the dispute itself, with deep-rooted internal and external factors. In the near future,China-Japan security relations will face more challenges than opportunities. China should take measures, including enhancing mutual trust in politics and security between the two countries, to impose necessary pressure on Japan to change course, to win over neighboring countries so as to avoid pretext for Japan's intervention in regional issues,and to strengthen interpersonal communication and understanding between people of the two countries in order to stabilize security relations.
基金This work was supported by the National Natural Science Foundation of China[grant numbers 42130504 and 41721004].
文摘The authors’previous study identified the wave trains of intraseasonal oscillations,which are mainly in the band of 10–30 days,over the North Pacific during summer.The wave trains are zonally oriented and trapped along the upper-tropospheric westerly jet,and accordingly gain energy mainly through baroclinic energy conversion.In this study,the authors investigate the distinct features of the wave trains between early summer(1 June to 7 July)and late summer(8 July to 31 August),considering that the westerly jet experiences a remarkable subseasonal variation over the North Pacific during summer—that is,the jet is much stronger in early summer than late summer.The results indicate that the wave trains are stronger in early summer compared with late summer.Further analysis suggests that,in early summer,the wave trains can obtain energy more efficiently from the basic flow;or more exactly,stronger westerlies through baroclinic energy conversion.
文摘Purpose: Traumatic optic neuropathy (TON) is a serious complication of head trauma with the incidence rate of 0.5%-5%. The aim of this study was to investigate the therapeutic efficacy of endoscopic decompression of the optic canal for optic nerve injuries. Methods: In this study, 11 patients treated in our hospital from January 2009 to January 2015 with the visual loss resulting from TON were retrospectively reviewed for preoperative vision, visual evoked potential (VEP) scan, surgical approach, postoperative visual acuity, complications, and follow-up results. Results: All these patients received endoscopic decompression of the optic canal. At the 3-month follow- up, the visual acuity improvement rate of the 11 patients was 45.5%. The vision acuity of 2 cases improved from hand movement to 0.08 and 0.3 after operation. Another patient's vision acuity returned to 0.05 compared to light sensation preoperatively. Two cases had finger counting before surgery but they had a vision acuity of 0.4 and light sensation respectively after surgery. However, the other 6 cases' vision did not improve after surgery. Conclusion: Endoscopic decompression of the optic canal is an effective way to cure TON. VEP could be used as an important reference for preoperative and prognosis evaluation. Operative time after trauma is only a relative condition that may affect the therapeutic effect of optic canal decompression. Poor results of this procedure may be related to the severity of the optic nerve injury.