Pulling growth technique serves as a popular method to grow congruent melting single crystals with multiscale sizes ranging from micrometers to centimeters.In order to obtain high quality single crystals,the crystal c...Pulling growth technique serves as a popular method to grow congruent melting single crystals with multiscale sizes ranging from micrometers to centimeters.In order to obtain high quality single crystals,the crystal constituents would be arranged at the lattice sites by precisely controlling the crystal growth process.Growing interface is the position where the phase transition of crystal constituents occurs during pulling growth process.The precise control of energy at the growing interface becomes a key technique in pulling growth.In this work,we review some recent advances of pulling technique towards rare earth single crystal growth.In Czochralski pulling growth,the optimized growth parameters were designed for rare earth ions doped Y_3Al_5O_(12)and Ce:(Lu_(1-x)Y_x)_2Si O_5on the basis of anisotropic chemical bonding and isotropic mass transfer calculations at the growing interface.The fast growth of high quality rare earth single crystals is realized by controlling crystallization thermodynamics and kinetics in different size zones.On the other hand,the micro pulling down technique can be used for high throughput screening novel rare earth optical crystals.The growth interface control is realized by improving the crucible bottom and temperature field,which favors the growth of rare earth crystal fibers.The rare earth laser crystal fiber can serve as another kind of laser gain medium between conventional bulk single crystal and glass fiber.The future work on pulling technique might focus on the mass production of rare earth single crystals with extreme size and with the size near that of devices.展开更多
Usually,an unfocused light beam,such as a paraxial Gaussian beam,can exert a force on an object along the direction of light propagation,which is known as light pressure.Recently,however,it was found that an unfocused...Usually,an unfocused light beam,such as a paraxial Gaussian beam,can exert a force on an object along the direction of light propagation,which is known as light pressure.Recently,however,it was found that an unfocused light beam can also exert an optical pulling force(OPF)on an object toward the source direction;the beam is accordingly named an optical tractor beam.In recent years,this intriguing force has attracted much attention and a huge amount of progress has been made both in theory and experiment.We briefly review recent progress achieved on this topic.We classify the mechanisms to achieve an OPF into four different kinds according to the dominant factors.The first one is tailoring the incident beam.The second one is engineering the object’s optical parameters.The third one is designing the structured material background,in which the light–matter interaction occurs,and the fourth one is utilizing the indirect photophoretic force,which is related to the thermal effect of light absorption.For all the methods,we analyze the basic principles and review the recent achievements.Finally,we also give a brief conclusion and an outlook on the future development of this field.展开更多
Radial drilling technology, of which the jet bit is the key device, is a research focus in the field of oil drilling and production. This paper establishes mechanical equations for jet bits and analyzes the hydroseal ...Radial drilling technology, of which the jet bit is the key device, is a research focus in the field of oil drilling and production. This paper establishes mechanical equations for jet bits and analyzes the hydroseal of backward jets in bottom holes. Meanwhile this paper establishes a mechanical equation for a high pressure hose and analyzes the axial force distribution. Laboratory experiments indicate that the flow rate, the angle between the backward nozzle axis and the jet bit axis, and the hole diameter are the major influencing factors; the generation of the pulling force is mainly due to the inlet pressure of the jet bit; the backward jets can significantly increase not only the pulling force but also the stability of jet bits. The pulling force would reach 8,376 N under experimental conditions, which can steadily pull the high-pressure hose forward.展开更多
During the harvesting process,rigid materials are prone to causing damage to the cotton stalks,which will increase the risk of stalk breakage.A cotton stalk pulling component that blends stiff and flexible materials w...During the harvesting process,rigid materials are prone to causing damage to the cotton stalks,which will increase the risk of stalk breakage.A cotton stalk pulling component that blends stiff and flexible materials was devised to lower the breaking rate.The cotton stalk pulling component was made up of rollers and flexible belts that pull the stalks using clamping force and the forward speed of the tractor.The influence of various factors in the equipment on the harvesting effect of cotton stalks were analyzed through response surface experiments,and a multiple quadratic regression response surface model with missing pulling rate and breakage rate as response values was established.The significant of influencing factors on the breaking rate of cotton stalks are in a descending order as:the angle of cotton stalk pulling,tractor’s forward speed,and the clamping speed of the cotton stalk component.The working parameters of the wheel-belt type cotton stalk pulling machine have been optimized using the response surface combination experimental method,and the optimal parameter combination was obtained as:tractor forward speed of 4.5 km/h,cotton stalk pulling angle of 60°,and clamping speed of the cotton stalk pulling component of 349 r/min.The results of validation experiments showed that the missing pulling rate of cotton stalks was 5.06%and the breakage rate was 13.12%,indicating a good harvesting effect of the cotton stalks.The model was reasonable and the performance parameters could meet the relevant inspection requirements.The results can provide a reference for further research on the technology of flexible cotton stalk pulling.展开更多
基金supported by Jilin Province Science and Technology Development Project(Grant No.21521092JH)
文摘Pulling growth technique serves as a popular method to grow congruent melting single crystals with multiscale sizes ranging from micrometers to centimeters.In order to obtain high quality single crystals,the crystal constituents would be arranged at the lattice sites by precisely controlling the crystal growth process.Growing interface is the position where the phase transition of crystal constituents occurs during pulling growth process.The precise control of energy at the growing interface becomes a key technique in pulling growth.In this work,we review some recent advances of pulling technique towards rare earth single crystal growth.In Czochralski pulling growth,the optimized growth parameters were designed for rare earth ions doped Y_3Al_5O_(12)and Ce:(Lu_(1-x)Y_x)_2Si O_5on the basis of anisotropic chemical bonding and isotropic mass transfer calculations at the growing interface.The fast growth of high quality rare earth single crystals is realized by controlling crystallization thermodynamics and kinetics in different size zones.On the other hand,the micro pulling down technique can be used for high throughput screening novel rare earth optical crystals.The growth interface control is realized by improving the crucible bottom and temperature field,which favors the growth of rare earth crystal fibers.The rare earth laser crystal fiber can serve as another kind of laser gain medium between conventional bulk single crystal and glass fiber.The future work on pulling technique might focus on the mass production of rare earth single crystals with extreme size and with the size near that of devices.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.11874134 and 11474077).
文摘Usually,an unfocused light beam,such as a paraxial Gaussian beam,can exert a force on an object along the direction of light propagation,which is known as light pressure.Recently,however,it was found that an unfocused light beam can also exert an optical pulling force(OPF)on an object toward the source direction;the beam is accordingly named an optical tractor beam.In recent years,this intriguing force has attracted much attention and a huge amount of progress has been made both in theory and experiment.We briefly review recent progress achieved on this topic.We classify the mechanisms to achieve an OPF into four different kinds according to the dominant factors.The first one is tailoring the incident beam.The second one is engineering the object’s optical parameters.The third one is designing the structured material background,in which the light–matter interaction occurs,and the fourth one is utilizing the indirect photophoretic force,which is related to the thermal effect of light absorption.For all the methods,we analyze the basic principles and review the recent achievements.Finally,we also give a brief conclusion and an outlook on the future development of this field.
基金supported by High-tech Research and Development Program of China (No. 2007AA09Z315)Doctoral Foundation of Ministry of Education of China (No. 20070425006)
文摘Radial drilling technology, of which the jet bit is the key device, is a research focus in the field of oil drilling and production. This paper establishes mechanical equations for jet bits and analyzes the hydroseal of backward jets in bottom holes. Meanwhile this paper establishes a mechanical equation for a high pressure hose and analyzes the axial force distribution. Laboratory experiments indicate that the flow rate, the angle between the backward nozzle axis and the jet bit axis, and the hole diameter are the major influencing factors; the generation of the pulling force is mainly due to the inlet pressure of the jet bit; the backward jets can significantly increase not only the pulling force but also the stability of jet bits. The pulling force would reach 8,376 N under experimental conditions, which can steadily pull the high-pressure hose forward.
基金financially supported by the National Nature Foundation Project(Grant No.52365038)the National Nature Foundation Project(Grant No.51865058)+3 种基金the Xinjiang Uygur Autonomous Region Agricultural Science and Technology Extension and Service Project(Grant No.NTFW-2022-17)the Xinjiang Uygur Autonomous Region Key R&D Project(Grant No.2022B02022-2)the Xinjiang Uygur Autonomous Region Key R&D Project(Grant No.2022B02023-3)the Xinjiang Uygur Autonomous Region Youth Science Fund(Grant No.2022D01B91).
文摘During the harvesting process,rigid materials are prone to causing damage to the cotton stalks,which will increase the risk of stalk breakage.A cotton stalk pulling component that blends stiff and flexible materials was devised to lower the breaking rate.The cotton stalk pulling component was made up of rollers and flexible belts that pull the stalks using clamping force and the forward speed of the tractor.The influence of various factors in the equipment on the harvesting effect of cotton stalks were analyzed through response surface experiments,and a multiple quadratic regression response surface model with missing pulling rate and breakage rate as response values was established.The significant of influencing factors on the breaking rate of cotton stalks are in a descending order as:the angle of cotton stalk pulling,tractor’s forward speed,and the clamping speed of the cotton stalk component.The working parameters of the wheel-belt type cotton stalk pulling machine have been optimized using the response surface combination experimental method,and the optimal parameter combination was obtained as:tractor forward speed of 4.5 km/h,cotton stalk pulling angle of 60°,and clamping speed of the cotton stalk pulling component of 349 r/min.The results of validation experiments showed that the missing pulling rate of cotton stalks was 5.06%and the breakage rate was 13.12%,indicating a good harvesting effect of the cotton stalks.The model was reasonable and the performance parameters could meet the relevant inspection requirements.The results can provide a reference for further research on the technology of flexible cotton stalk pulling.
