The twin-body plasma arc has the decoupling control ability of heat transfer and mass transfer,which is beneficial to shape and property control in wire arc additive manufacturing.In this paper,with the wire feeding s...The twin-body plasma arc has the decoupling control ability of heat transfer and mass transfer,which is beneficial to shape and property control in wire arc additive manufacturing.In this paper,with the wire feeding speed as a characteristic quantity,the wire melting control ability of twin-body plasma arc was studied by adjusting the current separation ratio(under the condition of a constant total current),the wire current/main current and the position of the wire in the arc axial direction.The results showed that under the premise that the total current remains unchanged(100 A),as the current separation ratio increased,the middle and minimum melting amounts increased approximately synchronously under the effect of anode effect power,the first melting mass range remained constant;the maximum melting amount increased twice as fast as the middle melting amount under the effect of the wire feeding speed,and the second melting mass range was expanded.When the wire current increased,the anode effect power and the plasma arc power were both factors causing the increase in the wire melting amount;however,when the main current increased,the plasma arc power was the only factor causing the increase in the wire melting amount.The average wire melting increment caused by the anode effect power was approximately 2.7 times that caused by the plasma arc power.The minimum melting amount was not affected by the wire-torch distance under any current separation ratio tested.When the current separation ratio increased and reached a threshold,the middle melting amount remained constant with increasing wire-torch distance.When the current separation ratio continued to increase and reached the next threshold,the maximum melting amount remained constant with the increasing wire-torch distance.The effect of the wire-torch distance on the wire melting amount reduced with the increase in the current separation ratio.Through this study,the decoupling mechanism and ability of this innovative arc heat source is more clearly.展开更多
AIM:To investigate the underlying factors by establishing a new paradigm for assessing control ability under stereopsis testing conditions.METHODS:This was a prospective observational study.We evaluated the control ab...AIM:To investigate the underlying factors by establishing a new paradigm for assessing control ability under stereopsis testing conditions.METHODS:This was a prospective observational study.We evaluated the control ability of intermittent exotropia(IXT)patients in three conditions:natural 2D optotype viewing,2D optotype viewing with polarized glasses,and 3D optotype viewing with polarized glasses.Recording with a smartphone,we captured videos to analyze the accurate time of spontaneous exodeviation and subsequent realignment before and after breaking fusion.Additionally,the correlation of stereopsis were also analyzed.RESULTS:A total of 48 patients(age range:4-33y;54.17%male)participated in the study.When viewing 3D optotypes with polarized glasses,their median control scores were 1(interquartile range,0-4)at distance and 0(0-1)at near.These scores were significantly better than those observed under natural viewing conditions,which were 2.5(1-5)at a distance and 1(0-3)at near(Friedman test,P=0.049).Furthermore,those subjects who exhibited exophoria(realignment within 2 seconds)while viewing 3D optotypes with polarized glasses were more likely to have measurable stereo vision(Kendall’sτb=-0.344,P=0.018).CONCLUSION:IXT patients exhibit enhanced control ability when using polarized glasses to view 3D optotypes,notably improving realignment capabilities.This expands our understanding of current tests and offers a potentially sensitive method for assessing IXT severity.展开更多
The gush-out water in the mineral pit endangers the underground mine safety directly. It is an important task for underground mine to guarantee its safety during the flood season. The authors analyzed the status of wa...The gush-out water in the mineral pit endangers the underground mine safety directly. It is an important task for underground mine to guarantee its safety during the flood season. The authors analyzed the status of water prevention and control in Chengchao Iron Mine,China,and put forward the necessary measures. The hydrogeological parameter controls the design of mine water prevention and affects the mineral well safety in operation. Enhance supervision and control,keeping the current facilities intact,using the existing pump house and the underground tunnel to adjust and control the amount of water and improving the hydrogeological conditions in the mine are the practical and remedial measures.展开更多
The country has a vast land area, rich in water resources and mineral resources, which plays an important role in China's economic and scientific and technological development. However, due to the gradual growth o...The country has a vast land area, rich in water resources and mineral resources, which plays an important role in China's economic and scientific and technological development. However, due to the gradual growth of population in recent years, the need for resources is increasing, especially water resources. In addition, for a long time, the industrial development of water resources brought huge pollution, so that the country's water resources are extremely serious. Based on this, even countries with abundant water resources still have a low equilibrium level of water resources per capita, and water resources are extremely scarce in most regions. For this problem, water conservancy project research and control personnel, should face up to the rational use and development of water resources, increase the awareness of water resources conservation and maintenance, improve the water conservancy project management level, can ensure the sustainable development of water resources in the future. This paper analyzes the current situation and importance of water resources management, and probes into the application of hydrology and water resources control in water conservancy projects, hoping to provide reference for the development of water conservancy. China is rich in water resources, but most of them are concentrated in the southeast of China. The per capita water resources are not sufficient and the water pollution is serious. Therefore, it is necessary to improve the management of hydrological resources in an all-round way. The use of hydrological resource management and control in water conservancy projects can provide better accurate information for the operation and management of water conservancy projects and ensure the normal operation of water conservancy projects.展开更多
New techniques for controlling the amplitudes of two orthogonal linearly polarized light are presented. One is based on adjusting the DC voltage into a Mach–Zehnder modulator（MZM） to alter the amplitude of the ligh...New techniques for controlling the amplitudes of two orthogonal linearly polarized light are presented. One is based on adjusting the DC voltage into a Mach–Zehnder modulator（MZM） to alter the amplitude of the light traveling on the slow axis of a fiber into the modulator with little changes in the fast-axis light amplitude.Another is based on adjusting the input DC voltages of a dual-polarization MZM operating in the reverse direction, which enables independent control of the two input orthogonal linearly polarized light amplitudes.Experimental results demonstrate that more than 30 dB difference in slow-and fast-axis light power can be obtained by controlling an MZM input DC voltage, and over 24 dB independent power adjustment for light traveling on the slow and fast axes into a dual-polarization MZM.展开更多
Detailed unsteady numerical simulation has been carried out to investigate the mechanism of adjacent syntheticjets and the influence of different phases on the mixing of coaxial jets. The results show the combined jet...Detailed unsteady numerical simulation has been carried out to investigate the mechanism of adjacent syntheticjets and the influence of different phases on the mixing of coaxial jets. The results show the combined jet, formedby coupling the vortex pairs at the orifice of two adjacent actuators, can exhibit better controlling effect. Spanwisepressure difference appears because of the existence of phase difference between the left jet and right jet, whichresults in the variation of the combined jet. When the phase difference is greater than zero, mixing enhancementof coaxial jets can be achieved, but there are maximum phase difference and optimal phase difference. On thecontrary, application of adjacent synthetic jets always leads to the mixing reduction when phase difference is lessthan zero.展开更多
基金Supported by Youth Program of National Natural Science Foundation of China(Grant No.51905008)Beijing Postdoctoral Research Foundation of China(Grant No.2021-zz-064)+2 种基金Shandong Provincial Major Science and Technology Innovation Project of China(Grant No.2020JMRH0504)Jinan Innovation Team Project of China(Grant No.2021GXRC066)Quancheng Scholars Construction Project of China(Grant No.D03032).
文摘The twin-body plasma arc has the decoupling control ability of heat transfer and mass transfer,which is beneficial to shape and property control in wire arc additive manufacturing.In this paper,with the wire feeding speed as a characteristic quantity,the wire melting control ability of twin-body plasma arc was studied by adjusting the current separation ratio(under the condition of a constant total current),the wire current/main current and the position of the wire in the arc axial direction.The results showed that under the premise that the total current remains unchanged(100 A),as the current separation ratio increased,the middle and minimum melting amounts increased approximately synchronously under the effect of anode effect power,the first melting mass range remained constant;the maximum melting amount increased twice as fast as the middle melting amount under the effect of the wire feeding speed,and the second melting mass range was expanded.When the wire current increased,the anode effect power and the plasma arc power were both factors causing the increase in the wire melting amount;however,when the main current increased,the plasma arc power was the only factor causing the increase in the wire melting amount.The average wire melting increment caused by the anode effect power was approximately 2.7 times that caused by the plasma arc power.The minimum melting amount was not affected by the wire-torch distance under any current separation ratio tested.When the current separation ratio increased and reached a threshold,the middle melting amount remained constant with increasing wire-torch distance.When the current separation ratio continued to increase and reached the next threshold,the maximum melting amount remained constant with the increasing wire-torch distance.The effect of the wire-torch distance on the wire melting amount reduced with the increase in the current separation ratio.Through this study,the decoupling mechanism and ability of this innovative arc heat source is more clearly.
基金Supported by the National Natural Science Foundation of China(No.82070995,No.82301256)Youth S&T Talent Support Programme of Guangdong Provincial Association for Science and Technology.
文摘AIM:To investigate the underlying factors by establishing a new paradigm for assessing control ability under stereopsis testing conditions.METHODS:This was a prospective observational study.We evaluated the control ability of intermittent exotropia(IXT)patients in three conditions:natural 2D optotype viewing,2D optotype viewing with polarized glasses,and 3D optotype viewing with polarized glasses.Recording with a smartphone,we captured videos to analyze the accurate time of spontaneous exodeviation and subsequent realignment before and after breaking fusion.Additionally,the correlation of stereopsis were also analyzed.RESULTS:A total of 48 patients(age range:4-33y;54.17%male)participated in the study.When viewing 3D optotypes with polarized glasses,their median control scores were 1(interquartile range,0-4)at distance and 0(0-1)at near.These scores were significantly better than those observed under natural viewing conditions,which were 2.5(1-5)at a distance and 1(0-3)at near(Friedman test,P=0.049).Furthermore,those subjects who exhibited exophoria(realignment within 2 seconds)while viewing 3D optotypes with polarized glasses were more likely to have measurable stereo vision(Kendall’sτb=-0.344,P=0.018).CONCLUSION:IXT patients exhibit enhanced control ability when using polarized glasses to view 3D optotypes,notably improving realignment capabilities.This expands our understanding of current tests and offers a potentially sensitive method for assessing IXT severity.
文摘The gush-out water in the mineral pit endangers the underground mine safety directly. It is an important task for underground mine to guarantee its safety during the flood season. The authors analyzed the status of water prevention and control in Chengchao Iron Mine,China,and put forward the necessary measures. The hydrogeological parameter controls the design of mine water prevention and affects the mineral well safety in operation. Enhance supervision and control,keeping the current facilities intact,using the existing pump house and the underground tunnel to adjust and control the amount of water and improving the hydrogeological conditions in the mine are the practical and remedial measures.
文摘The country has a vast land area, rich in water resources and mineral resources, which plays an important role in China's economic and scientific and technological development. However, due to the gradual growth of population in recent years, the need for resources is increasing, especially water resources. In addition, for a long time, the industrial development of water resources brought huge pollution, so that the country's water resources are extremely serious. Based on this, even countries with abundant water resources still have a low equilibrium level of water resources per capita, and water resources are extremely scarce in most regions. For this problem, water conservancy project research and control personnel, should face up to the rational use and development of water resources, increase the awareness of water resources conservation and maintenance, improve the water conservancy project management level, can ensure the sustainable development of water resources in the future. This paper analyzes the current situation and importance of water resources management, and probes into the application of hydrology and water resources control in water conservancy projects, hoping to provide reference for the development of water conservancy. China is rich in water resources, but most of them are concentrated in the southeast of China. The per capita water resources are not sufficient and the water pollution is serious. Therefore, it is necessary to improve the management of hydrological resources in an all-round way. The use of hydrological resource management and control in water conservancy projects can provide better accurate information for the operation and management of water conservancy projects and ensure the normal operation of water conservancy projects.
文摘New techniques for controlling the amplitudes of two orthogonal linearly polarized light are presented. One is based on adjusting the DC voltage into a Mach–Zehnder modulator（MZM） to alter the amplitude of the light traveling on the slow axis of a fiber into the modulator with little changes in the fast-axis light amplitude.Another is based on adjusting the input DC voltages of a dual-polarization MZM operating in the reverse direction, which enables independent control of the two input orthogonal linearly polarized light amplitudes.Experimental results demonstrate that more than 30 dB difference in slow-and fast-axis light power can be obtained by controlling an MZM input DC voltage, and over 24 dB independent power adjustment for light traveling on the slow and fast axes into a dual-polarization MZM.
基金National Natural Science Foundation of China for-the support projects Grant No.50806006.
文摘Detailed unsteady numerical simulation has been carried out to investigate the mechanism of adjacent syntheticjets and the influence of different phases on the mixing of coaxial jets. The results show the combined jet, formedby coupling the vortex pairs at the orifice of two adjacent actuators, can exhibit better controlling effect. Spanwisepressure difference appears because of the existence of phase difference between the left jet and right jet, whichresults in the variation of the combined jet. When the phase difference is greater than zero, mixing enhancementof coaxial jets can be achieved, but there are maximum phase difference and optimal phase difference. On thecontrary, application of adjacent synthetic jets always leads to the mixing reduction when phase difference is lessthan zero.
