In recent years,China has implemented measures to advance the building of a unified national market,aiming to boost domestic demand and consolidate the foundations of its economic recovery.In March 2022,the Chinese go...In recent years,China has implemented measures to advance the building of a unified national market,aiming to boost domestic demand and consolidate the foundations of its economic recovery.In March 2022,the Chinese government issued a guideline on accelerating the construction of a unified national market.The issue was also a focus at the annual Central Economic Work Conference held in December 2023.展开更多
The Cap Pushing Response (CPR) is a free-flying technique used to study learning and memory in honey bees (Apis mellifera). The series of experiments outlined in this paper aimed to test whether honey bees exhibit the...The Cap Pushing Response (CPR) is a free-flying technique used to study learning and memory in honey bees (Apis mellifera). The series of experiments outlined in this paper aimed to test whether honey bees exhibit the cognitive concept of “expectancy” utilizing the CPR in a weight differentiation paradigm. Five previous experiments in our laboratory have explored whether the concept of expectancy can account for honey bee performance and have all failed to support the cognitive interpretation. The first experiment examined if bees could differentiate between the two caps in the amount of force they used to push the cap and the distance the cap was pushed when the caps were presented one at a time. The second experiment explored cap weight preference by presenting bees with a choice between the two caps. The third and fourth experiments tested the bee’s ability to expect reward or punishment based on cap weight. Results revealed that bees were found to have a strong preference for the light cap and therefore were not able to expect reward or punishment based on cap weight. These experiments contribute to the debate on whether bees have “cognitive” representations and continue to support the behaviorist interpretation.展开更多
MANCHESTER,UK-Having successfully demonstrated its WebSpector automated fabric inspection system detecting faults on camouflage fabrics at speeds of up to 100metres a minute during ITMA 2023,BTMA member Shelton Vision...MANCHESTER,UK-Having successfully demonstrated its WebSpector automated fabric inspection system detecting faults on camouflage fabrics at speeds of up to 100metres a minute during ITMA 2023,BTMA member Shelton Vision has secured an unprecedented number of new orders in many fields of the textile industry.The company has subsequently been recruiting additional staff in order to beef up its operations to meet delivery times and to grow capacity for the ongoing increased demand.展开更多
Half a century—plus 37 seconds—after it was first introduced to the world,the leap second has been scheduled for retirement.On 18 November 2022 at the General Conference on Weights and Measures(CGPM)outside of Paris...Half a century—plus 37 seconds—after it was first introduced to the world,the leap second has been scheduled for retirement.On 18 November 2022 at the General Conference on Weights and Measures(CGPM)outside of Paris,France,representatives of governments around the globe decided that astronomical time(known as UT1),which is determined by Earth’s rotation,will be allowed to diverge by more than one second from Coordinated Universal Time(UTC),which is based on the steady ticking of atomic clocks[1].While the change—not to be implemented until 2035—will go unnoticed by most people,it promises to simplify the timekeeping vital to services provided by a wide range of global industries,including transportation,defense,and finance.展开更多
“China is shoring up its position as the world leader in renewable power and potentially outpacing its own ambitious energy targets,”states a recent article in the British newspaper The Guardian.The piece,citing a r...“China is shoring up its position as the world leader in renewable power and potentially outpacing its own ambitious energy targets,”states a recent article in the British newspaper The Guardian.The piece,citing a report by Global Energy Monitor,finds China is set to double its capacity and produce 1,200 gigawatts of energy through wind and solar power by 2025,reaching its 2030 goal five years ahead of time,a development which a project manager at the firm said was“jaw-dropping”.展开更多
On a rainy night in October 1985,23-year-old archaeologist Zhang Xingde embarked on a 100-mile trek with the Niuheliang Hongshan Culture site excavation team including Guo Dashun to Xingcheng,where highly revered arch...On a rainy night in October 1985,23-year-old archaeologist Zhang Xingde embarked on a 100-mile trek with the Niuheliang Hongshan Culture site excavation team including Guo Dashun to Xingcheng,where highly revered archaeologist Su Bingqi was living.They brought a wooden box containing a goddess statue.展开更多
Confining stresses serve as a pivotal determinant in shaping the behavior of grouted rock bolts.Nonetheless,prior investigations have oversimplified the three-dimensional stress state,primarily assuming hydrostatic st...Confining stresses serve as a pivotal determinant in shaping the behavior of grouted rock bolts.Nonetheless,prior investigations have oversimplified the three-dimensional stress state,primarily assuming hydrostatic stress conditions.Under these conditions,it is assumed that the intermediate principal stress(σ_(2))equals the minimum principal stress(σ_(3)).This assumption overlooks the potential variations in magnitudes of in situ stress conditions along all three directions near an underground opening where a rock bolt is installed.In this study,a series of push tests was meticulously conducted under triaxial conditions.These tests involved applying non-uniform confining stresses(σ_(2)≠σ_(3))to cubic specimens,aiming to unveil the previously overlooked influence of intermediate principal stresses on the strength properties of rock bolts.The results show that as the confining stresses increase from zero to higher levels,the pre-failure behavior changes from linear to nonlinear forms,resulting in an increase in initial stiffness from 2.08 kN/mm to 32.51 kN/mm.The load-displacement curves further illuminate distinct post-failure behavior at elevated levels of confining stresses,characterized by enhanced stiffness.Notably,the peak load capacity ranged from 27.9 kN to 46.5 kN as confining stresses advanced from σ_(2)=σ_(3)=0 to σ_(2)=20 MPa and σ_(3)=10 MPa.Additionally,the outcomes highlight an influence of confining stress on the lateral deformation of samples.Lower levels of confinement prompt overall dilation in lateral deformation,while higher confinements maintain a state of shrinkage.Furthermore,diverse failure modes have been identified,intricately tied to the arrangement of confining stresses.Lower confinements tend to induce a splitting mode of failure,whereas higher loads bring about a shift towards a pure interfacial shear-off and shear-crushed failure mechanism.展开更多
Afterburning behind the detonation front of an aluminized explosive releases energy on the millisecond timescale,which prolong the release of detonation energy and the energy release at different stages also shows sig...Afterburning behind the detonation front of an aluminized explosive releases energy on the millisecond timescale,which prolong the release of detonation energy and the energy release at different stages also shows significant differences.However,at present,there are few effective methods for evaluating the energy release characteristics of the middle reaction stage of such explosives,which can have a duration of tens to hundreds of microseconds.The present work demonstrates an approach to assessing the midstage of an aluminized explosive detonation based on a water push test employing a high degree of confinement.In this method,the explosive is contained in a steel cylinder having one end closed that is installed at the bottom of a transparent water tank.Upon detonation,the gaseous products expand in one direction while forcing water ahead of them.The resulting underwater shock wave and the interface between the gas phase products and the water are tracked using an ultra-high-speed framing and streak camera.The shock wave velocity in water and the expansion work performed by the gaseous detonation products were calculated to assess the energy release characteristics of aluminized explosives such as CL-20 and RDX in the middle stage of the detonation reaction.During the middle stage of the detonation process of these aluminized explosives,the aluminum reaction reduced the attenuation of shock waves and increased the work performed by gas phase products.A higher aluminum content increased the energy output while the presence of oxidants slowed the energy release rate.This work demonstrates an effective means of evaluating the performance of aluminized explosives.展开更多
Key policy document sets goals for China’s rural work for 2023 China has outlined nine key tasks for comprehensively promoting rural revitalisation this year in the “No.1 central document” of 2023 released on 13 Fe...Key policy document sets goals for China’s rural work for 2023 China has outlined nine key tasks for comprehensively promoting rural revitalisation this year in the “No.1 central document” of 2023 released on 13 February. As the first policy statement from China’s central authorities each year, the document.展开更多
As Africa pushes forward its industrialisation process,the Chinese-built industrial parks and free trade zones have assumed special significance as drivers of the region’s industrial development and job creation.At t...As Africa pushes forward its industrialisation process,the Chinese-built industrial parks and free trade zones have assumed special significance as drivers of the region’s industrial development and job creation.At the same time,Africa is also learning from China’s successful experience in industrialisation.What are the ways in which China and African countries can deepen industrial cooperation?What are the roadblocks to such cooperation and the process of industrialisation in Africa?展开更多
Understanding the dominant force responsible for supercontinent breakup is crucial for establishing Earth's geodynamic evolution that includes supercontinent cycles and plate tectonics. Conventionally,two forces have...Understanding the dominant force responsible for supercontinent breakup is crucial for establishing Earth's geodynamic evolution that includes supercontinent cycles and plate tectonics. Conventionally,two forces have been considered: the push by mantle plumes from the sub-continental mantle which is called the active force for breakup, and the dragging force from oceanic subduction retreat which is called the passive force for breakup. However, the relative importance of these two forces is unclear. Here we model the supercontinent breakup coupled with global mantle convection in order to address this question. Our global model features a spherical harmonic degree-2 structure, which includes a major subduction girdle and two large upwelling(superplume) systems. Based on this global mantle structure,we examine the distribution of extensional stress applied to the supercontinent by both subsupercontinent mantle upwellings and subduction retreat at the supercontinent peripheral. Our results show that:(1) at the center half of the supercontinent, plume push stress is ~3 times larger than the stress induced by subduction retreat;(2) an average hot anomaly of no higher than 50 K beneath the supercontinent can produce a push force strong enough to cause the initialization of supercontinent breakup;(3) the extensional stress induced by subduction retreat concentrates on a ~600 km wide zone on the boundary of the supercontinent, but has far less impact to the interior of the supercontinent. We therefore conclude that although circum-supercontinent subduction retreat assists supercontinent breakup, sub-supercontinent mantle upwelling is the essential force.展开更多
The diagnosis and opportunity for endoscopic therapy of gastric or duodenal lesions may be missed at esophagogastroduodenoscopy(EGD) because of technical difficulty in intubating at EGD the postoperatively excluded st...The diagnosis and opportunity for endoscopic therapy of gastric or duodenal lesions may be missed at esophagogastroduodenoscopy(EGD) because of technical difficulty in intubating at EGD the postoperatively excluded stomach and proximal duodenum in patients status post Roux-en-Y gastric bypass(RYGB). Two cases are reported of acute upper gastrointestinal bleeding 10 or 11 years status postRYGB, performed for morbid obesity, in which the EGD was non-diagnostic due to failure to intubate the excluded stomach and proximal duodenum, whereas subsequent push enteroscopy or single balloon enteroscopy were diagnostic and revealed 4-cm-wide or 5-mm-wide bulbar ulcers and even permitted application of endoscopic therapy. These case reports suggest consideration of push enteroscopy, or single balloon enteroscopy, where available, in the endoscopic evaluation of acute UGI bleeding in patients status post RYGB surgery when the EGD was non-diagnostic because of failure to intubate these excluded segments.展开更多
On 9 September 2016,global Internet data traffic flew past the milestone of 1 ZB,or 1021 bytes-a trillion gigabytes-per year.If you imagine every one of those gigabytes as a brick,a trillion of them would allow you to...On 9 September 2016,global Internet data traffic flew past the milestone of 1 ZB,or 1021 bytes-a trillion gigabytes-per year.If you imagine every one of those gigabytes as a brick,a trillion of them would allow you to build 258 Great Walls of China,one analyst estimated[1].It took nearly 40 years for the Internet to hit that mark.By 2022,annual Internet traffic is expected to reach almost 5 ZB[2].展开更多
Objective: To compare maternal and fetal outcome associated with two methods Reverse breech extraction versus Head pushing to deliver the impacted fetal head in advanced labor requiring emergency Cesarean section. Met...Objective: To compare maternal and fetal outcome associated with two methods Reverse breech extraction versus Head pushing to deliver the impacted fetal head in advanced labor requiring emergency Cesarean section. Method: A prospective comparative study was conducted on 80 pregnant women at term with cephalic presentation in advanced labour, requiring emergency Cesarean Section. Reverse breech extraction technique (pull method) was used in 40 cases (group I) and pushing the head up through the vagina (“push” method) was tried in (group II) 40 cases. The maternal outcome was assessed by extension of the uterine Incision, bladder injury, intra and postoperative blood transfusion, Postpartum hemorrhage, wound infection and duration of hospital stay. Fetal outcome was Apgar score and admission to neonatal intensive care unit. Results: Extension of the uterine incision was significantly lower in women undergoing reverse breech extraction compared to cephalic delivery (20% versus 50%;p = 0.001). The mean operative time (pull group) was lower than that in the (push group) 59.7 ± 4.2, versus 75.2 ± 6.1 p = 0.001 and blood loss was significantly lower in the (pull group) than that in the (push group) 878 ± 67 ml, versus 1321 ± 57 ml, p = 0.001. No significant difference between groups regarding maternal and neonatal outcome. Conclusion: Reverse breech extraction (pull) is safer than pushing head up through vagina (push) for delivery of a deeply impacted fetal head in advanced labour sensitizing emergency Cesarean Section and is associated with the least maternal complications.展开更多
The movie Pushing Hands demonstrated the conflicts in the process of intercultural communication between China andwestern countries, revealing different perspectives of culture values. However, these conflicts of inte...The movie Pushing Hands demonstrated the conflicts in the process of intercultural communication between China andwestern countries, revealing different perspectives of culture values. However, these conflicts of intercultural communication canbe handled by accepting and communicating, and understanding others' cultures.展开更多
In recent years,China's college English education has achieved a great success.However,at the same time,it also brings a lot of negative effects,and problems emerge endlessly.According to her own learning experien...In recent years,China's college English education has achieved a great success.However,at the same time,it also brings a lot of negative effects,and problems emerge endlessly.According to her own learning experience,as well as combining the experience of her own college English teaching,the writer is trying to combine the famous marketing theory"Push& Pull" with college English teaching methods,hoping to provide some suggestions to improve the current teaching situation.展开更多
Due to the influence of material characteristics and winding power, single output electromagnet has limited ability to improve the dynamic characteristic of electro-hydraulic valve. Therefore, an electromechanical con...Due to the influence of material characteristics and winding power, single output electromagnet has limited ability to improve the dynamic characteristic of electro-hydraulic valve. Therefore, an electromechanical converter with double push rods is proposed in this paper, which can simultaneously output two electromagnetic forces, can push or pull the valve core and sleeve according to the current direction and realize rapid operation of load. According to the electromagnetic principle and the magnetic circuit analysis method, the mathematical model and equivalent circuit of the electromechanical converter with double push rods are established. Through the finite element simulation model of the electromechanical converter with double push rods with the same magnetization directions, the changing rules of its magnetic field distribution and force–displacement behaviors are studied and analyzed. According to the analysis results, the electromagnetic mechanical parameters and mechanical structure of the electromechanical converter with double push rods are determined, and the prototype is made. The test platform for the push-pull characteristics of the electromechanical converter with double push rods is built, and its static and dynamic characteristics are tested and analyzed. The results show that the thrust and pull output characteristics of the internal and external push rods are basically consistent with the simulation output, and proportional to the current density of the coil;the push-pull hysteresis of internal and external push rods output force is less than 5%;and the dynamic time response characteristics of the displacement and force are obtained. The hysteresis e ect of output force is improved e ectively through the H bridge drive control circuit modulated by PWM. Compared with the displacement response of a singlewinding electromagnet with a similar volume, it can e ectively improve the dynamic displacement response. Followup work will further optimize the structure of the electromechanical converter and test the corresponding pilot valve. The research results provide a new theory for improving the output characteristics of electro-hydraulic pilot valve and have an extremely high engineering application value and broad application prospect.展开更多
文摘In recent years,China has implemented measures to advance the building of a unified national market,aiming to boost domestic demand and consolidate the foundations of its economic recovery.In March 2022,the Chinese government issued a guideline on accelerating the construction of a unified national market.The issue was also a focus at the annual Central Economic Work Conference held in December 2023.
文摘The Cap Pushing Response (CPR) is a free-flying technique used to study learning and memory in honey bees (Apis mellifera). The series of experiments outlined in this paper aimed to test whether honey bees exhibit the cognitive concept of “expectancy” utilizing the CPR in a weight differentiation paradigm. Five previous experiments in our laboratory have explored whether the concept of expectancy can account for honey bee performance and have all failed to support the cognitive interpretation. The first experiment examined if bees could differentiate between the two caps in the amount of force they used to push the cap and the distance the cap was pushed when the caps were presented one at a time. The second experiment explored cap weight preference by presenting bees with a choice between the two caps. The third and fourth experiments tested the bee’s ability to expect reward or punishment based on cap weight. Results revealed that bees were found to have a strong preference for the light cap and therefore were not able to expect reward or punishment based on cap weight. These experiments contribute to the debate on whether bees have “cognitive” representations and continue to support the behaviorist interpretation.
文摘MANCHESTER,UK-Having successfully demonstrated its WebSpector automated fabric inspection system detecting faults on camouflage fabrics at speeds of up to 100metres a minute during ITMA 2023,BTMA member Shelton Vision has secured an unprecedented number of new orders in many fields of the textile industry.The company has subsequently been recruiting additional staff in order to beef up its operations to meet delivery times and to grow capacity for the ongoing increased demand.
文摘Half a century—plus 37 seconds—after it was first introduced to the world,the leap second has been scheduled for retirement.On 18 November 2022 at the General Conference on Weights and Measures(CGPM)outside of Paris,France,representatives of governments around the globe decided that astronomical time(known as UT1),which is determined by Earth’s rotation,will be allowed to diverge by more than one second from Coordinated Universal Time(UTC),which is based on the steady ticking of atomic clocks[1].While the change—not to be implemented until 2035—will go unnoticed by most people,it promises to simplify the timekeeping vital to services provided by a wide range of global industries,including transportation,defense,and finance.
文摘“China is shoring up its position as the world leader in renewable power and potentially outpacing its own ambitious energy targets,”states a recent article in the British newspaper The Guardian.The piece,citing a report by Global Energy Monitor,finds China is set to double its capacity and produce 1,200 gigawatts of energy through wind and solar power by 2025,reaching its 2030 goal five years ahead of time,a development which a project manager at the firm said was“jaw-dropping”.
文摘On a rainy night in October 1985,23-year-old archaeologist Zhang Xingde embarked on a 100-mile trek with the Niuheliang Hongshan Culture site excavation team including Guo Dashun to Xingcheng,where highly revered archaeologist Su Bingqi was living.They brought a wooden box containing a goddess statue.
文摘Confining stresses serve as a pivotal determinant in shaping the behavior of grouted rock bolts.Nonetheless,prior investigations have oversimplified the three-dimensional stress state,primarily assuming hydrostatic stress conditions.Under these conditions,it is assumed that the intermediate principal stress(σ_(2))equals the minimum principal stress(σ_(3)).This assumption overlooks the potential variations in magnitudes of in situ stress conditions along all three directions near an underground opening where a rock bolt is installed.In this study,a series of push tests was meticulously conducted under triaxial conditions.These tests involved applying non-uniform confining stresses(σ_(2)≠σ_(3))to cubic specimens,aiming to unveil the previously overlooked influence of intermediate principal stresses on the strength properties of rock bolts.The results show that as the confining stresses increase from zero to higher levels,the pre-failure behavior changes from linear to nonlinear forms,resulting in an increase in initial stiffness from 2.08 kN/mm to 32.51 kN/mm.The load-displacement curves further illuminate distinct post-failure behavior at elevated levels of confining stresses,characterized by enhanced stiffness.Notably,the peak load capacity ranged from 27.9 kN to 46.5 kN as confining stresses advanced from σ_(2)=σ_(3)=0 to σ_(2)=20 MPa and σ_(3)=10 MPa.Additionally,the outcomes highlight an influence of confining stress on the lateral deformation of samples.Lower levels of confinement prompt overall dilation in lateral deformation,while higher confinements maintain a state of shrinkage.Furthermore,diverse failure modes have been identified,intricately tied to the arrangement of confining stresses.Lower confinements tend to induce a splitting mode of failure,whereas higher loads bring about a shift towards a pure interfacial shear-off and shear-crushed failure mechanism.
基金supported by the National Natural Science Foundation of China(Grant No.11832006)。
文摘Afterburning behind the detonation front of an aluminized explosive releases energy on the millisecond timescale,which prolong the release of detonation energy and the energy release at different stages also shows significant differences.However,at present,there are few effective methods for evaluating the energy release characteristics of the middle reaction stage of such explosives,which can have a duration of tens to hundreds of microseconds.The present work demonstrates an approach to assessing the midstage of an aluminized explosive detonation based on a water push test employing a high degree of confinement.In this method,the explosive is contained in a steel cylinder having one end closed that is installed at the bottom of a transparent water tank.Upon detonation,the gaseous products expand in one direction while forcing water ahead of them.The resulting underwater shock wave and the interface between the gas phase products and the water are tracked using an ultra-high-speed framing and streak camera.The shock wave velocity in water and the expansion work performed by the gaseous detonation products were calculated to assess the energy release characteristics of aluminized explosives such as CL-20 and RDX in the middle stage of the detonation reaction.During the middle stage of the detonation process of these aluminized explosives,the aluminum reaction reduced the attenuation of shock waves and increased the work performed by gas phase products.A higher aluminum content increased the energy output while the presence of oxidants slowed the energy release rate.This work demonstrates an effective means of evaluating the performance of aluminized explosives.
文摘Key policy document sets goals for China’s rural work for 2023 China has outlined nine key tasks for comprehensively promoting rural revitalisation this year in the “No.1 central document” of 2023 released on 13 February. As the first policy statement from China’s central authorities each year, the document.
文摘As Africa pushes forward its industrialisation process,the Chinese-built industrial parks and free trade zones have assumed special significance as drivers of the region’s industrial development and job creation.At the same time,Africa is also learning from China’s successful experience in industrialisation.What are the ways in which China and African countries can deepen industrial cooperation?What are the roadblocks to such cooperation and the process of industrialisation in Africa?
基金supported by Australian Research Council Australian Laureate Fellowship grant to ZXL (FL150100133)by China’s Thousand Talents Plan (2015)+2 种基金NSFC41674098 to NZsupported by resources provided by the High-performance Computing Platform of Peking Universitythe Pawsey Supercomputing Centre with funding from the Australian Government and the Government of Western Australia
文摘Understanding the dominant force responsible for supercontinent breakup is crucial for establishing Earth's geodynamic evolution that includes supercontinent cycles and plate tectonics. Conventionally,two forces have been considered: the push by mantle plumes from the sub-continental mantle which is called the active force for breakup, and the dragging force from oceanic subduction retreat which is called the passive force for breakup. However, the relative importance of these two forces is unclear. Here we model the supercontinent breakup coupled with global mantle convection in order to address this question. Our global model features a spherical harmonic degree-2 structure, which includes a major subduction girdle and two large upwelling(superplume) systems. Based on this global mantle structure,we examine the distribution of extensional stress applied to the supercontinent by both subsupercontinent mantle upwellings and subduction retreat at the supercontinent peripheral. Our results show that:(1) at the center half of the supercontinent, plume push stress is ~3 times larger than the stress induced by subduction retreat;(2) an average hot anomaly of no higher than 50 K beneath the supercontinent can produce a push force strong enough to cause the initialization of supercontinent breakup;(3) the extensional stress induced by subduction retreat concentrates on a ~600 km wide zone on the boundary of the supercontinent, but has far less impact to the interior of the supercontinent. We therefore conclude that although circum-supercontinent subduction retreat assists supercontinent breakup, sub-supercontinent mantle upwelling is the essential force.
文摘The diagnosis and opportunity for endoscopic therapy of gastric or duodenal lesions may be missed at esophagogastroduodenoscopy(EGD) because of technical difficulty in intubating at EGD the postoperatively excluded stomach and proximal duodenum in patients status post Roux-en-Y gastric bypass(RYGB). Two cases are reported of acute upper gastrointestinal bleeding 10 or 11 years status postRYGB, performed for morbid obesity, in which the EGD was non-diagnostic due to failure to intubate the excluded stomach and proximal duodenum, whereas subsequent push enteroscopy or single balloon enteroscopy were diagnostic and revealed 4-cm-wide or 5-mm-wide bulbar ulcers and even permitted application of endoscopic therapy. These case reports suggest consideration of push enteroscopy, or single balloon enteroscopy, where available, in the endoscopic evaluation of acute UGI bleeding in patients status post RYGB surgery when the EGD was non-diagnostic because of failure to intubate these excluded segments.
文摘On 9 September 2016,global Internet data traffic flew past the milestone of 1 ZB,or 1021 bytes-a trillion gigabytes-per year.If you imagine every one of those gigabytes as a brick,a trillion of them would allow you to build 258 Great Walls of China,one analyst estimated[1].It took nearly 40 years for the Internet to hit that mark.By 2022,annual Internet traffic is expected to reach almost 5 ZB[2].
文摘Objective: To compare maternal and fetal outcome associated with two methods Reverse breech extraction versus Head pushing to deliver the impacted fetal head in advanced labor requiring emergency Cesarean section. Method: A prospective comparative study was conducted on 80 pregnant women at term with cephalic presentation in advanced labour, requiring emergency Cesarean Section. Reverse breech extraction technique (pull method) was used in 40 cases (group I) and pushing the head up through the vagina (“push” method) was tried in (group II) 40 cases. The maternal outcome was assessed by extension of the uterine Incision, bladder injury, intra and postoperative blood transfusion, Postpartum hemorrhage, wound infection and duration of hospital stay. Fetal outcome was Apgar score and admission to neonatal intensive care unit. Results: Extension of the uterine incision was significantly lower in women undergoing reverse breech extraction compared to cephalic delivery (20% versus 50%;p = 0.001). The mean operative time (pull group) was lower than that in the (push group) 59.7 ± 4.2, versus 75.2 ± 6.1 p = 0.001 and blood loss was significantly lower in the (pull group) than that in the (push group) 878 ± 67 ml, versus 1321 ± 57 ml, p = 0.001. No significant difference between groups regarding maternal and neonatal outcome. Conclusion: Reverse breech extraction (pull) is safer than pushing head up through vagina (push) for delivery of a deeply impacted fetal head in advanced labour sensitizing emergency Cesarean Section and is associated with the least maternal complications.
文摘The movie Pushing Hands demonstrated the conflicts in the process of intercultural communication between China andwestern countries, revealing different perspectives of culture values. However, these conflicts of intercultural communication canbe handled by accepting and communicating, and understanding others' cultures.
文摘In recent years,China's college English education has achieved a great success.However,at the same time,it also brings a lot of negative effects,and problems emerge endlessly.According to her own learning experience,as well as combining the experience of her own college English teaching,the writer is trying to combine the famous marketing theory"Push& Pull" with college English teaching methods,hoping to provide some suggestions to improve the current teaching situation.
基金Supported by National Natural Science Foundation for Young Scientists of China(Grant No.51505317)Shanxi Provincial Natural Science Foundation of China(Grant No.201601D102039)
文摘Due to the influence of material characteristics and winding power, single output electromagnet has limited ability to improve the dynamic characteristic of electro-hydraulic valve. Therefore, an electromechanical converter with double push rods is proposed in this paper, which can simultaneously output two electromagnetic forces, can push or pull the valve core and sleeve according to the current direction and realize rapid operation of load. According to the electromagnetic principle and the magnetic circuit analysis method, the mathematical model and equivalent circuit of the electromechanical converter with double push rods are established. Through the finite element simulation model of the electromechanical converter with double push rods with the same magnetization directions, the changing rules of its magnetic field distribution and force–displacement behaviors are studied and analyzed. According to the analysis results, the electromagnetic mechanical parameters and mechanical structure of the electromechanical converter with double push rods are determined, and the prototype is made. The test platform for the push-pull characteristics of the electromechanical converter with double push rods is built, and its static and dynamic characteristics are tested and analyzed. The results show that the thrust and pull output characteristics of the internal and external push rods are basically consistent with the simulation output, and proportional to the current density of the coil;the push-pull hysteresis of internal and external push rods output force is less than 5%;and the dynamic time response characteristics of the displacement and force are obtained. The hysteresis e ect of output force is improved e ectively through the H bridge drive control circuit modulated by PWM. Compared with the displacement response of a singlewinding electromagnet with a similar volume, it can e ectively improve the dynamic displacement response. Followup work will further optimize the structure of the electromechanical converter and test the corresponding pilot valve. The research results provide a new theory for improving the output characteristics of electro-hydraulic pilot valve and have an extremely high engineering application value and broad application prospect.