In modem manufacturing, a new type of sheet metal part with step cross-section in both inner hole and outer edge is proposed. The traditional stamping separating processes can only produce sheet metal part with vertic...In modem manufacturing, a new type of sheet metal part with step cross-section in both inner hole and outer edge is proposed. The traditional stamping separating processes can only produce sheet metal part with vertical cross-section. According to the latest developing theory and potential of cold pressure forming： combination of pressure and cold forging, a new flow control forming of sheet metal（FCF） is excogitated based on blanking process of general stamping and combined with cold forging processes such as extrusion and coining, etc, which is aiming at the above-mentioned new type of sheet metal part. With utilization of this new process, the new type of sheet metal parts can be manufactured. In order to shorten the testing period, the numerical simulation was carried out by using DEFORM-3D software, and both deformation and mechanics rules were analyzed. Based on the simulation, both punching part and blanked parts of this new type were successfully developed. Then a new conception of optimal distance between the step walls of inner hole and outside edge was proposed and the design principle for its numerical value was inferred. Furthermore, a mold set for combination of stamping ＆ cold forging was designed and manufactured, by which the technologic experiments were taken for validation with Aluminum plate of thickness 2.35 mm for power battery cover board, which verified the principle of the distance between the step walls. The research of cold pressure forming of thin sheet metal with step cross-section is significant, not only to the development of modem mechanical manufacture, but also to metal plastic forming science.展开更多
Objective: to explore the nursing experience of prevention of intestinal flatulence by acupoint massage and exhaust exercise after cesarean section. Methods: 100 parturients who underwent caesarean section with acupun...Objective: to explore the nursing experience of prevention of intestinal flatulence by acupoint massage and exhaust exercise after cesarean section. Methods: 100 parturients who underwent caesarean section with acupuncture point massage and exhaust exercise were selected and randomly divided into the control group and the observation group. The control group received routine nursing while the observation group received nursing intervention. The nursing quality of the parturients in both groups was counted. Results: the nursing quality of parturients in the observation group was better than that in the control group (P<0.05). Conclusion: abdominal distension will occur after caesarean section. Therefore, post-operative acupuncture point massage exercise should be performed clinically to reduce flatulence of parturients undergoing caesarean section, improve gastrointestinal function of parturients undergoing caesarean section, maintain intestinal peristalsis of parturients undergoing caesarean section, restore normal indexes of the body, and promote anal exhaust. High-quality nursing is indispensable during the implementation of acupuncture point massage exhaust exercise. The exploration of cesarean section parturient exhaust exercise, combined with the basic actual situation of cesarean section parturient, conforms to the cesarean section parturients own condition, formulates effective nursing policy for cesarean section parturient. During the period of acupuncture point nursing for cesarean section parturient, continuous education should be given to enable them to cooperate with the nursing work and improve the details of clinical nursing by combining with the specific opinions of cesarean section parturient on the nursing work, which has high clinical practicality.展开更多
While electrospinning is an effective method for fabricating nanofibers with good application prospects,controlling the length of stable section of electrospinning jet is critical and remains challenging.In the paper,...While electrospinning is an effective method for fabricating nanofibers with good application prospects,controlling the length of stable section of electrospinning jet is critical and remains challenging.In the paper,the effects of electrospinning parameters on the length of stable section have been investigated experimentally using polyacrylonitrile(PAN).The results based on single factor experiments and orthogonal experiments showed that the stable⁃jet length increased with the increase of solution concentration,receiving distance,voltage and solution flow rate,and decreased with the enhanced concentration of salt which was commonly utilized as additive to facilitate the spinning.Furthermore,experimental results based on polyethylene oxide(PEO)and polyvinyl alcohol(PVA)showed that the length of stable section changed with increasing salt concentration,and due to the parametric interaction,the change was distinct under different driving voltages or solution concentration conditions.展开更多
The aerodynamic characteristics of projectiles with triangular and circular cross sections are investigated respectively by use of free-flight experiment.Processed the experiment data,curves of flight velocity variati...The aerodynamic characteristics of projectiles with triangular and circular cross sections are investigated respectively by use of free-flight experiment.Processed the experiment data,curves of flight velocity variation and nutation of both projectiles are obtained,based on the curves,their aerodynamic force and moment coefficients are found out by data fitting,and their aerodynamic performances are compared and analyzed.Results show that the projectile with triangular cross section has smaller resistance,higher lift-drag ratio,better static stability,higher stability capability and more excellent maneuverability than those of the projectile with circular cross section,therefore it can be used in the guided projectiles;under lower rotation speed,the triangular section projectile has greater Magnus moment leading to bigger projectile distribution.展开更多
On the purpose of accurate data acquisition for the aeroacoustic testing mostly in open jet test section of aeroacoustic wind tunnel, the large scale anechoic chamber is specifically designed to build the low backgrou...On the purpose of accurate data acquisition for the aeroacoustic testing mostly in open jet test section of aeroacoustic wind tunnel, the large scale anechoic chamber is specifically designed to build the low background noise environment. A newly acoustic test section is presented in this paper, of which the contour is similar as the closed test section, and the wall is fabricated by the fiber fabric, both the characteristics of closed and open jet test section of conventional wind tunnel are combined in it. By thoroughly researching on the acoustics and aerodynamics of this acoustically transparent test section, significant progress in reducing the background noises in test section and improving the ratio of energy of the wind tunnel and some other aspects have been achieved. Acoustically transparent test section behaves better in acoustics and aerodynamics than conventional acoustic test section because of their high definition in detecting the sound sources and great performance in transmitting sounds.展开更多
文摘In modem manufacturing, a new type of sheet metal part with step cross-section in both inner hole and outer edge is proposed. The traditional stamping separating processes can only produce sheet metal part with vertical cross-section. According to the latest developing theory and potential of cold pressure forming： combination of pressure and cold forging, a new flow control forming of sheet metal（FCF） is excogitated based on blanking process of general stamping and combined with cold forging processes such as extrusion and coining, etc, which is aiming at the above-mentioned new type of sheet metal part. With utilization of this new process, the new type of sheet metal parts can be manufactured. In order to shorten the testing period, the numerical simulation was carried out by using DEFORM-3D software, and both deformation and mechanics rules were analyzed. Based on the simulation, both punching part and blanked parts of this new type were successfully developed. Then a new conception of optimal distance between the step walls of inner hole and outside edge was proposed and the design principle for its numerical value was inferred. Furthermore, a mold set for combination of stamping ＆ cold forging was designed and manufactured, by which the technologic experiments were taken for validation with Aluminum plate of thickness 2.35 mm for power battery cover board, which verified the principle of the distance between the step walls. The research of cold pressure forming of thin sheet metal with step cross-section is significant, not only to the development of modem mechanical manufacture, but also to metal plastic forming science.
文摘Objective: to explore the nursing experience of prevention of intestinal flatulence by acupoint massage and exhaust exercise after cesarean section. Methods: 100 parturients who underwent caesarean section with acupuncture point massage and exhaust exercise were selected and randomly divided into the control group and the observation group. The control group received routine nursing while the observation group received nursing intervention. The nursing quality of the parturients in both groups was counted. Results: the nursing quality of parturients in the observation group was better than that in the control group (P<0.05). Conclusion: abdominal distension will occur after caesarean section. Therefore, post-operative acupuncture point massage exercise should be performed clinically to reduce flatulence of parturients undergoing caesarean section, improve gastrointestinal function of parturients undergoing caesarean section, maintain intestinal peristalsis of parturients undergoing caesarean section, restore normal indexes of the body, and promote anal exhaust. High-quality nursing is indispensable during the implementation of acupuncture point massage exhaust exercise. The exploration of cesarean section parturient exhaust exercise, combined with the basic actual situation of cesarean section parturient, conforms to the cesarean section parturients own condition, formulates effective nursing policy for cesarean section parturient. During the period of acupuncture point nursing for cesarean section parturient, continuous education should be given to enable them to cooperate with the nursing work and improve the details of clinical nursing by combining with the specific opinions of cesarean section parturient on the nursing work, which has high clinical practicality.
基金National Natural Science Foundation of China(Nos.51773037,51973027,51803023,and 61771123)Fundamental Research Funds for the Central Universities(Nos.2232020D⁃15,2232020A⁃08,2232020G⁃01,2232020D⁃14,and 2232018A3⁃11)+3 种基金Changjiang Youth Scholars Program of ChinaInnovation Program of Shanghai Municipal Education Commission,ChinaShanghai Sailing Program,China(No.18YF 1400400)China Postdoctoral Science Foundation(No.2018M640317)。
文摘While electrospinning is an effective method for fabricating nanofibers with good application prospects,controlling the length of stable section of electrospinning jet is critical and remains challenging.In the paper,the effects of electrospinning parameters on the length of stable section have been investigated experimentally using polyacrylonitrile(PAN).The results based on single factor experiments and orthogonal experiments showed that the stable⁃jet length increased with the increase of solution concentration,receiving distance,voltage and solution flow rate,and decreased with the enhanced concentration of salt which was commonly utilized as additive to facilitate the spinning.Furthermore,experimental results based on polyethylene oxide(PEO)and polyvinyl alcohol(PVA)showed that the length of stable section changed with increasing salt concentration,and due to the parametric interaction,the change was distinct under different driving voltages or solution concentration conditions.
基金Supported by the National Natural Science Foundation of China （Nos. 11105081, 11275110 and 11375103） and the National Energy Application Project For Research and Demonstration （No. 20131660315）.
基金Sponsored by Foundation of National Defense Key Laboratory
文摘The aerodynamic characteristics of projectiles with triangular and circular cross sections are investigated respectively by use of free-flight experiment.Processed the experiment data,curves of flight velocity variation and nutation of both projectiles are obtained,based on the curves,their aerodynamic force and moment coefficients are found out by data fitting,and their aerodynamic performances are compared and analyzed.Results show that the projectile with triangular cross section has smaller resistance,higher lift-drag ratio,better static stability,higher stability capability and more excellent maneuverability than those of the projectile with circular cross section,therefore it can be used in the guided projectiles;under lower rotation speed,the triangular section projectile has greater Magnus moment leading to bigger projectile distribution.
文摘On the purpose of accurate data acquisition for the aeroacoustic testing mostly in open jet test section of aeroacoustic wind tunnel, the large scale anechoic chamber is specifically designed to build the low background noise environment. A newly acoustic test section is presented in this paper, of which the contour is similar as the closed test section, and the wall is fabricated by the fiber fabric, both the characteristics of closed and open jet test section of conventional wind tunnel are combined in it. By thoroughly researching on the acoustics and aerodynamics of this acoustically transparent test section, significant progress in reducing the background noises in test section and improving the ratio of energy of the wind tunnel and some other aspects have been achieved. Acoustically transparent test section behaves better in acoustics and aerodynamics than conventional acoustic test section because of their high definition in detecting the sound sources and great performance in transmitting sounds.
