Electrohydrodynamic(EHD)jet printing represents a novel micro/nano-scale additive manufacturing process that utilises a high-voltage induced electric field between the nozzle and the substrate to print micro/nanoscale...Electrohydrodynamic(EHD)jet printing represents a novel micro/nano-scale additive manufacturing process that utilises a high-voltage induced electric field between the nozzle and the substrate to print micro/nanoscale structures.EHD printing is particularly advantageous for the fabrication on flexible or non-flat substrates and of large aspect ratio micro/nanostructures and composite multi-material structures.Despite this,EHD printing has yet to be fully industrialised due to its low throughput,which is primarily caused by the limitations of serial additive printing technology.The parallel multi-nozzle array-based process has become the most promising option for EHD printing to achieve large-scale printing by increasing the number of nozzles to realise multichannel parallel printing.This paper reviews the recent development of multi-nozzle EHD printing technology,analyses jet motion with multi-nozzle,explains the origins of the electric field crosstalk effect under multi-nozzle and discusses several widely used methods for overcoming it.This work also summarises the impact of different process parameters on multi-nozzle EHD printing and describes the current manufacturing process using multi-nozzle as well as the method by which they can be realised independently.In addition,it presents an additional significant utilisation of multi-nozzle printing aside from enhancing single-nozzle production efficiency,which is the production of composite phase change materials through multi-nozzle.Finally,the future direction of multi-nozzle EHD printing development is discussed and envisioned.展开更多
Opposed multi-burner(OMB)gasification technology is the first large-scale gasification technology developed in China with completely independent intellectual property rights.It has been widely used around the world,in...Opposed multi-burner(OMB)gasification technology is the first large-scale gasification technology developed in China with completely independent intellectual property rights.It has been widely used around the world,involving synthetic ammonia,methanol,ethylene glycol,coal liquefaction,hydrogen production and other fields.This paper summarizes the research and development process of OMB gasification technology from the perspective of the cold model experiment and process simulation,pilotscale study and industrial demonstration.The latest progress of fundamental research in nozzle atomization and dispersion,mixing enhancement of impinging flow,multiscale reaction of different carbonaceous feedstocks,spectral characteristic of impinging flame and particle characteristics inside gasifier,and comprehensive gasification model are reviewed.The latest industrial application progress of ultralarge-scale OMB gasifier and radiant syngas cooler(RSC)combined with quenching chamber OMB gasifier are introduced,and the prospects for the future technical development are proposed as well.展开更多
In order to meet the requirements of the machining process of cone screw of the Opposed Conical High Pressure Seawater Hydraulic Pump,this work describes the design process to determine the theoretical profile of the ...In order to meet the requirements of the machining process of cone screw of the Opposed Conical High Pressure Seawater Hydraulic Pump,this work describes the design process to determine the theoretical profile of the tool,starting from the surface equation of the cone screw. Along with the expression of the theoretical tool profile,the equation of the contact line between the cone screw and the tool is established based on the coordinate transformation theory and the space meshing theory,as well as the surface equation and the position relationship between the screw and the tool during processing. By solving the contact condition based on the method of numerical discretization analysis via MATLAB,the contact line trajectory and theoretical tool profile curve are derived.The feasibility of the proposed method is verified by an example of tool profile design for machining the screw.展开更多
Based on the prototypes of a 130 t/h boiler, constant proportional cold-state test bench is established, flow characteristics of multi-nozzle in natural gas reburning burner and its influence on the covering effect fo...Based on the prototypes of a 130 t/h boiler, constant proportional cold-state test bench is established, flow characteristics of multi-nozzle in natural gas reburning burner and its influence on the covering effect for the upflow in the furnace are researched. Numerical simulations of this process are also made with standard ?turbulence model. The results show that air flow fullness in furnace is better in the case of the reburning zone with 8 nozzles compared to 4 nozzles and also coverage effect of the reburning flow for the updraft gas in the furnace is better. In the condition each nozzle airflow velocity is constant, the effect of reburning flow on coverage of up-secondary air is best when the incident angle for four corners is 14.17?, while Center of the furnace wall is 84.57. And while the best incident angle is invariable, the effect of reburning flow on coverage of up-secondary air is best when the speed of reburning gas in the corners of furnace is 51 m/s, the same to the center of the furnace wall’s.展开更多
The Great Gatsby narrates a symbolist tragedy in a transitional era.It’s ambivalent characterizationand themes find justifications in the writer’s own ideology of two opposed ideas ,and in his efforts to define andj...The Great Gatsby narrates a symbolist tragedy in a transitional era.It’s ambivalent characterizationand themes find justifications in the writer’s own ideology of two opposed ideas ,and in his efforts to define andjudge subjects of social problems.The ambivalent characterization concerns the writer’s dual response to theprotagonist’s corruption and innocence respectively.Ultimately the writer is convinced that both the corruptionand innocence are justifiable in the morality of his protagonist.Whereas the ambivalent themes dealing withthe American dream attach importance to the social class perspectives and the vision of history,undoubtedlythe writer slides into a compromise with his themes:repudation and approval.Because of the equally strong in-terplay of two opposed ideas,the writer fails to locate a definite position and scale,which results in his imma-ture control in the art of the work.The writer’s characteristic code and achievement are significant becausethey genuinely reveal human being’s fundamental dilemma in social life.展开更多
To experimentally match performance and structural features of an opposed-piston two- stroke engine （ OPTSE ）, two calculation models, a one-dimensional （ 1-D ） model and a three-di- mensional （3-D） model, of th...To experimentally match performance and structural features of an opposed-piston two- stroke engine （ OPTSE ）, two calculation models, a one-dimensional （ 1-D ） model and a three-di- mensional （3-D） model, of the combined charging matching simulation of an OPTSE was established by using the GT-Power software. To test and verify the one dimensional model, the three-dimension- al computational fluid dynamics simulation model was established using AVL FIRE software. Cylinder pressure curves in these two models match perfectly, showing that it is reasonable to use the one-di- mensional model to simulate the work process of an OPTSE. Moreover, the effects of delivery ratio, nozzle ring diameter and exhaust back pressure on brake specific fuel consumption （ BSFC ） were studied.展开更多
In order to improve the thermal power conversion capacity of the internal combustion engine,combined with existing opposed-piston two-stroke engine（ OP2S） and hydraulic free piston engine（HFPE）,the integral struct...In order to improve the thermal power conversion capacity of the internal combustion engine,combined with existing opposed-piston two-stroke engine（ OP2S） and hydraulic free piston engine（HFPE）,the integral structure for a newtype of opposed-piston hydraulic-output（ OPHO） engine has been designed,an operating principle has been introduced,the composition of its synchronous drive mechanism has been carefully analyzed,and a mathematical model has been built. In addition,the kinematics models of both the mechanism and the conventional crank-link mechanism have been established by utilizing MATLAB,and the movement rules of the pivotal moving components have been obtained. According to the simulation results,the piston movement of this newtype of opposed-piston hydraulic-output engine reveals a prominent asymmetry compared to the conventional crank-link engine. Under a fixed engine revolving speed,the compression time of the opposedpiston hydraulic-output engine is shortened while the expanding time is lengthened,thus the gas turbulence intensity is strengthened around the top dead center（ TDC） position. Meanwhile,the piston obtains a longer isometric process compared to conventional engines,which could be benefitial to enhance the combustion efficiency.展开更多
The effects of different flow forms on an opposed-piston two-stroke（OPTS）gasoline-directinjection（GDI）engine was studied by analyzing the mixture formation and combustion.Swirl was broken and dissipated gradually ...The effects of different flow forms on an opposed-piston two-stroke（OPTS）gasoline-directinjection（GDI）engine was studied by analyzing the mixture formation and combustion.Swirl was broken and dissipated gradually and the turbulence kinetic energy（TKE）was small in the compression process;however,tumble was strengthened and the TKE was strong in the compression process.For swirl around X axis（the axis of cylinder）and tumble around Y axis（the vertical direction of injector）,droplets were attached to the cylinder liner by the centrifugal force and the mixture distribution was poor.For tumble around Zaxis（the direction of injector）,the wall film in cylinder liner was thin and mixture distribution was homogeneous.Results showed that since the injector were installed on the wall of the cylinder liner in the OPTS-GDI engine,the spray angle was small and the mixture formation time was short.The 45° oblique axis tumble ratio of 1 was reasonable for the mixture formation and combustion for an OPTS-GDI engine.展开更多
A frequency compensation control method for the opposed-piston two-stroke folded-cranktrain（ OPFC） diesel engine＇s common rail system is presented as a result of the study of the loop-shaping theory. A common rail ...A frequency compensation control method for the opposed-piston two-stroke folded-cranktrain（ OPFC） diesel engine＇s common rail system is presented as a result of the study of the loop-shaping theory. A common rail working process and the classical frequency control theory are combined to construct a frequency restriction of common rail pressure. A frequency compensator is utilized to improve the robustness of multiplicative perturbations and disturbance. The loop-shaping method has been applied to design the common rail pressure controller of the OPFC diesel engine. Simulation and bench test results show that in the condition of perturbation that comes from the effect of injection,multi-injection,fuel pumping of a pre-cylinder,and instantaneous pressure fluctuation,the controller indicates high precision. Compared with the original controller,this method improves the control precision by 67. 3%.展开更多
Objective To observe the clinical efficacy of opposing needling for the treatment of migraine with the symptom of hyperactivity of liver yang type and its effect on NO level in plasma of patients. Methods Atotal of 60...Objective To observe the clinical efficacy of opposing needling for the treatment of migraine with the symptom of hyperactivity of liver yang type and its effect on NO level in plasma of patients. Methods Atotal of 60 migraine patients with the symptom of hyperactivity of liver yang who met the inclusive criteria were randomly divided into a opposing needling group （group A） and a routine acupuncture group （group B） by using SPSS 15.0 software according to the registration order with 30 patients in each group. Patients in group A were treated with opposing needling. Taich6ng （太冲 LR 3）, Zhongzhu （中渚 TE 3）, ZOlfnqi （足临泣 GB 41） and QiOxu （丘墟 GB 40） in the uninjured side were selected. After deqi, reducing method was used. Then Taixi （太溪 KI 3） in the uninjured side was selected. After deqi, rein forcing method was used. Needles were retained for 30 rain. Patients in group B were treated with routine acupuncture. Local Ash point, Sishncong （ 四神聪EX-HN1）, Yifeng （翳风 TE 17）, Fengchi （风池 GB 20）, Sizhukong （丝竹空 TE 23）, Shuaigu （率谷GB 8）, Hegu （合谷 LI 4） and LiEque （列缺 LU 7） were selected. After puncturing, reducing method was used routinely and needles were retained for 30 rain. After 2 weeks treatment, migraine specific quality of life questionnaire （MSQ）, visual analogue scale （VAS） and nitric oxide （NO） level in plasma of patients in two groups were observed. Results After treatment, the MSQ, VAS and NO of two groups were significantly improved compared with those before treatment. After treatment, score of MSQ functional limitation was 73.41±10.22 in group A and 60.95 ± 10.15 in group B; the score of MSQ dysfunction was 86.11 ±8.22 in group A and 75.45±8.34 in group B; score of MSQ emotion was 80.51±10.16 in group A and 75.01± 10.20 in group B. The improvements of group A were superior to those of group B, and the differences were all statistically significant （all P〈0.05）. After treatment, the VAS score was 0.93 ± 1.25 in group A and 2.17± 1.70 in group B. The improvement of group A was superior to that of group B, and the difference was statistically significant （P〈0.05）. After treatment, blood plasma NO level was （42.15 ± 16.15） μmol/L in group A and （62.76±15.17） μmol/L in group B. The improvement of group A was superior to that of group B, and the difference was statistically significant （P〈0.05）. Overall response rate was 86.7% （26/30） in group A and 53.3% （16/30） in group B, and the difference between two groups was statistically significant （P〈0.05）. Conclusion Opposing needling is an effective method for the treatment of migraine with the symptom of hyperactivity of liver yong. Its mechanism is to regulate the generation of NO in migraine patients, and improve the relaxation and contraction of cerebral vascular smooth muscle, so as to adjust the cerebral circulation.展开更多
基金National Natural Science Foundation of China(Grant Nos.52275345,52175331)the Support plan for Outstanding Youth Innovation Team in Universities of Shandong Province,China(2021KJ044)Natural Science Foundation of Shandong Province,China(Granted No.ZR2020ZD04)。
文摘Electrohydrodynamic(EHD)jet printing represents a novel micro/nano-scale additive manufacturing process that utilises a high-voltage induced electric field between the nozzle and the substrate to print micro/nanoscale structures.EHD printing is particularly advantageous for the fabrication on flexible or non-flat substrates and of large aspect ratio micro/nanostructures and composite multi-material structures.Despite this,EHD printing has yet to be fully industrialised due to its low throughput,which is primarily caused by the limitations of serial additive printing technology.The parallel multi-nozzle array-based process has become the most promising option for EHD printing to achieve large-scale printing by increasing the number of nozzles to realise multichannel parallel printing.This paper reviews the recent development of multi-nozzle EHD printing technology,analyses jet motion with multi-nozzle,explains the origins of the electric field crosstalk effect under multi-nozzle and discusses several widely used methods for overcoming it.This work also summarises the impact of different process parameters on multi-nozzle EHD printing and describes the current manufacturing process using multi-nozzle as well as the method by which they can be realised independently.In addition,it presents an additional significant utilisation of multi-nozzle printing aside from enhancing single-nozzle production efficiency,which is the production of composite phase change materials through multi-nozzle.Finally,the future direction of multi-nozzle EHD printing development is discussed and envisioned.
基金supported by the National Natural Science Foundation of China(21776086,21761132034)。
文摘Opposed multi-burner(OMB)gasification technology is the first large-scale gasification technology developed in China with completely independent intellectual property rights.It has been widely used around the world,involving synthetic ammonia,methanol,ethylene glycol,coal liquefaction,hydrogen production and other fields.This paper summarizes the research and development process of OMB gasification technology from the perspective of the cold model experiment and process simulation,pilotscale study and industrial demonstration.The latest progress of fundamental research in nozzle atomization and dispersion,mixing enhancement of impinging flow,multiscale reaction of different carbonaceous feedstocks,spectral characteristic of impinging flame and particle characteristics inside gasifier,and comprehensive gasification model are reviewed.The latest industrial application progress of ultralarge-scale OMB gasifier and radiant syngas cooler(RSC)combined with quenching chamber OMB gasifier are introduced,and the prospects for the future technical development are proposed as well.
基金National Natural Science Foundation of China(No.51075008)
文摘In order to meet the requirements of the machining process of cone screw of the Opposed Conical High Pressure Seawater Hydraulic Pump,this work describes the design process to determine the theoretical profile of the tool,starting from the surface equation of the cone screw. Along with the expression of the theoretical tool profile,the equation of the contact line between the cone screw and the tool is established based on the coordinate transformation theory and the space meshing theory,as well as the surface equation and the position relationship between the screw and the tool during processing. By solving the contact condition based on the method of numerical discretization analysis via MATLAB,the contact line trajectory and theoretical tool profile curve are derived.The feasibility of the proposed method is verified by an example of tool profile design for machining the screw.
文摘Based on the prototypes of a 130 t/h boiler, constant proportional cold-state test bench is established, flow characteristics of multi-nozzle in natural gas reburning burner and its influence on the covering effect for the upflow in the furnace are researched. Numerical simulations of this process are also made with standard ?turbulence model. The results show that air flow fullness in furnace is better in the case of the reburning zone with 8 nozzles compared to 4 nozzles and also coverage effect of the reburning flow for the updraft gas in the furnace is better. In the condition each nozzle airflow velocity is constant, the effect of reburning flow on coverage of up-secondary air is best when the incident angle for four corners is 14.17?, while Center of the furnace wall is 84.57. And while the best incident angle is invariable, the effect of reburning flow on coverage of up-secondary air is best when the speed of reburning gas in the corners of furnace is 51 m/s, the same to the center of the furnace wall’s.
文摘The Great Gatsby narrates a symbolist tragedy in a transitional era.It’s ambivalent characterizationand themes find justifications in the writer’s own ideology of two opposed ideas ,and in his efforts to define andjudge subjects of social problems.The ambivalent characterization concerns the writer’s dual response to theprotagonist’s corruption and innocence respectively.Ultimately the writer is convinced that both the corruptionand innocence are justifiable in the morality of his protagonist.Whereas the ambivalent themes dealing withthe American dream attach importance to the social class perspectives and the vision of history,undoubtedlythe writer slides into a compromise with his themes:repudation and approval.Because of the equally strong in-terplay of two opposed ideas,the writer fails to locate a definite position and scale,which results in his imma-ture control in the art of the work.The writer’s characteristic code and achievement are significant becausethey genuinely reveal human being’s fundamental dilemma in social life.
基金Supported by the National Natural Science Foundation of China(B2220110005)
文摘To experimentally match performance and structural features of an opposed-piston two- stroke engine （ OPTSE ）, two calculation models, a one-dimensional （ 1-D ） model and a three-di- mensional （3-D） model, of the combined charging matching simulation of an OPTSE was established by using the GT-Power software. To test and verify the one dimensional model, the three-dimension- al computational fluid dynamics simulation model was established using AVL FIRE software. Cylinder pressure curves in these two models match perfectly, showing that it is reasonable to use the one-di- mensional model to simulate the work process of an OPTSE. Moreover, the effects of delivery ratio, nozzle ring diameter and exhaust back pressure on brake specific fuel consumption （ BSFC ） were studied.
基金Supported by the Basic Research Projects of National Ministries and Commissions(62201070215)
文摘In order to improve the thermal power conversion capacity of the internal combustion engine,combined with existing opposed-piston two-stroke engine（ OP2S） and hydraulic free piston engine（HFPE）,the integral structure for a newtype of opposed-piston hydraulic-output（ OPHO） engine has been designed,an operating principle has been introduced,the composition of its synchronous drive mechanism has been carefully analyzed,and a mathematical model has been built. In addition,the kinematics models of both the mechanism and the conventional crank-link mechanism have been established by utilizing MATLAB,and the movement rules of the pivotal moving components have been obtained. According to the simulation results,the piston movement of this newtype of opposed-piston hydraulic-output engine reveals a prominent asymmetry compared to the conventional crank-link engine. Under a fixed engine revolving speed,the compression time of the opposedpiston hydraulic-output engine is shortened while the expanding time is lengthened,thus the gas turbulence intensity is strengthened around the top dead center（ TDC） position. Meanwhile,the piston obtains a longer isometric process compared to conventional engines,which could be benefitial to enhance the combustion efficiency.
基金Supported by the National Natural Science Foundation of China(B2220110005)
文摘The effects of different flow forms on an opposed-piston two-stroke（OPTS）gasoline-directinjection（GDI）engine was studied by analyzing the mixture formation and combustion.Swirl was broken and dissipated gradually and the turbulence kinetic energy（TKE）was small in the compression process;however,tumble was strengthened and the TKE was strong in the compression process.For swirl around X axis（the axis of cylinder）and tumble around Y axis（the vertical direction of injector）,droplets were attached to the cylinder liner by the centrifugal force and the mixture distribution was poor.For tumble around Zaxis（the direction of injector）,the wall film in cylinder liner was thin and mixture distribution was homogeneous.Results showed that since the injector were installed on the wall of the cylinder liner in the OPTS-GDI engine,the spray angle was small and the mixture formation time was short.The 45° oblique axis tumble ratio of 1 was reasonable for the mixture formation and combustion for an OPTS-GDI engine.
基金Supported by the National Natural Science Foundation of China(51406013)
文摘A frequency compensation control method for the opposed-piston two-stroke folded-cranktrain（ OPFC） diesel engine＇s common rail system is presented as a result of the study of the loop-shaping theory. A common rail working process and the classical frequency control theory are combined to construct a frequency restriction of common rail pressure. A frequency compensator is utilized to improve the robustness of multiplicative perturbations and disturbance. The loop-shaping method has been applied to design the common rail pressure controller of the OPFC diesel engine. Simulation and bench test results show that in the condition of perturbation that comes from the effect of injection,multi-injection,fuel pumping of a pre-cylinder,and instantaneous pressure fluctuation,the controller indicates high precision. Compared with the original controller,this method improves the control precision by 67. 3%.
基金Supported by Traditional Chinese Medicine Bureau of Guangdong Province,project number:20141240
文摘Objective To observe the clinical efficacy of opposing needling for the treatment of migraine with the symptom of hyperactivity of liver yang type and its effect on NO level in plasma of patients. Methods Atotal of 60 migraine patients with the symptom of hyperactivity of liver yang who met the inclusive criteria were randomly divided into a opposing needling group （group A） and a routine acupuncture group （group B） by using SPSS 15.0 software according to the registration order with 30 patients in each group. Patients in group A were treated with opposing needling. Taich6ng （太冲 LR 3）, Zhongzhu （中渚 TE 3）, ZOlfnqi （足临泣 GB 41） and QiOxu （丘墟 GB 40） in the uninjured side were selected. After deqi, reducing method was used. Then Taixi （太溪 KI 3） in the uninjured side was selected. After deqi, rein forcing method was used. Needles were retained for 30 rain. Patients in group B were treated with routine acupuncture. Local Ash point, Sishncong （ 四神聪EX-HN1）, Yifeng （翳风 TE 17）, Fengchi （风池 GB 20）, Sizhukong （丝竹空 TE 23）, Shuaigu （率谷GB 8）, Hegu （合谷 LI 4） and LiEque （列缺 LU 7） were selected. After puncturing, reducing method was used routinely and needles were retained for 30 rain. After 2 weeks treatment, migraine specific quality of life questionnaire （MSQ）, visual analogue scale （VAS） and nitric oxide （NO） level in plasma of patients in two groups were observed. Results After treatment, the MSQ, VAS and NO of two groups were significantly improved compared with those before treatment. After treatment, score of MSQ functional limitation was 73.41±10.22 in group A and 60.95 ± 10.15 in group B; the score of MSQ dysfunction was 86.11 ±8.22 in group A and 75.45±8.34 in group B; score of MSQ emotion was 80.51±10.16 in group A and 75.01± 10.20 in group B. The improvements of group A were superior to those of group B, and the differences were all statistically significant （all P〈0.05）. After treatment, the VAS score was 0.93 ± 1.25 in group A and 2.17± 1.70 in group B. The improvement of group A was superior to that of group B, and the difference was statistically significant （P〈0.05）. After treatment, blood plasma NO level was （42.15 ± 16.15） μmol/L in group A and （62.76±15.17） μmol/L in group B. The improvement of group A was superior to that of group B, and the difference was statistically significant （P〈0.05）. Overall response rate was 86.7% （26/30） in group A and 53.3% （16/30） in group B, and the difference between two groups was statistically significant （P〈0.05）. Conclusion Opposing needling is an effective method for the treatment of migraine with the symptom of hyperactivity of liver yong. Its mechanism is to regulate the generation of NO in migraine patients, and improve the relaxation and contraction of cerebral vascular smooth muscle, so as to adjust the cerebral circulation.
