Taking Au?Cu system as an example, three discoveries and two methods were presented. First, a new way for boosting sustainable progress of systematic metal materials science (SMMS) and alloy gene engineering (AGE) is ...Taking Au?Cu system as an example, three discoveries and two methods were presented. First, a new way for boosting sustainable progress of systematic metal materials science (SMMS) and alloy gene engineering (AGE) is to establish holographic alloy positioning design (HAPD) system, of which the base consists of measurement and calculation center, SMMS center, AGE center, HAPD information center and HAPD cybernation center; Second, the resonance activating-sychro alternating mechanism of atom movement may be divided into the located and oriented diffuse modes; Third, the equilibrium and subequilibrium holographic network phase diagrams are blueprints and operable platform for researchers to discover, design, manufacture and deploy advanced alloys, which are obtained respectively by the equilibrium lever numerical method and cross point numerical method of isothermal Gibbs energy curves. As clicking each network point, the holographic information of three structure levels for the designed alloy may be readily obtained: the phase constitution and fraction, phase arranging structure and properties of organization; the composition, alloy gene arranging structure and properties of each phase and the electronic structures and properties of alloy genes. It will create a new era for network designing advanced alloys.展开更多
BACKGROUND Neuroendoscopy is a very useful technique to Chronic Subdural Hematoma(CSH).But how to achieve the goal of treatment more minimally invasive?AIM To develop a simple,fast and accurate preoperative planning m...BACKGROUND Neuroendoscopy is a very useful technique to Chronic Subdural Hematoma(CSH).But how to achieve the goal of treatment more minimally invasive?AIM To develop a simple,fast and accurate preoperative planning method in our way for endoscopic surgery of patients with CSH.METHODS From June 2018 to May 2020,forty-two patients with CSH,admitted to our hospital,were performed endoscopic minimally invasive surgery;computed tomography(CT)imaging was employed to locate the intracerebral hematoma and select the appropriate endoscopic approach before the endoscopic surgery.The clinical data and treatment efficacy were analyzed.RESULTS According to the learning of CT scanning images,the surgeon can accurately design the best minimally invasive neuroendoscopic surgical approach and realize the precise positioning and design of the drilling site of the skull and the size of the bone window,so as to provide the most effective operation space with the smallest bone window.In this group,the average operation time was only about 1 h,and the clearance rate of hematoma was about 95%.CONCLUSION Patients with CSH can achieve good therapeutic effect by using our way to positioning and design to assist the operation of CSH according to CT scan and image,and our way is very useful and necessary.展开更多
Baseline observation as well as height measurement is the important content of the quality control of high-rise building construction.In order to strengthen the quality of construction projects,meet the requirement of...Baseline observation as well as height measurement is the important content of the quality control of high-rise building construction.In order to strengthen the quality of construction projects,meet the requirement of completion time,improve the accuracy and efficiency of locating observation and explore a scientific way of observation suitable for high-rise building construction,this paper studies the design and implementation of high-rise building construction based on GPS positioning technology.展开更多
The proper choice of optomechanical components along with alignment techniques is vital to the successful implementation of lens positioning and mounting. In general, there is a trade-off between lens positioning accu...The proper choice of optomechanical components along with alignment techniques is vital to the successful implementation of lens positioning and mounting. In general, there is a trade-off between lens positioning accuracy and manufacturing cost. In order to achieve optimal precision- to-cost ratio, a careful optomechanical design together with accurate alignment and assembly is necessary. This paper presents a lens positioning and mounting in a few microns accuracy using a kinematic mount module. The optomechanical design of the kinematic mount module and the associated fixtures based on the simulation study of components sensitivity are presented. The processes for alignment and assembly, which separate decenter from tip-tilt, are developed and presented. Finally, the prototypes are created and testing results are presented. The optomechanical design that allows the separation of decenter from tip-tilt considerably simplifies the positioning and assembly process and reduces the cost for mass production.展开更多
University hall is an important carrier of information exchange and sharing in higher education campuses,and the correct architectural design positioning can improve the value of university halls.There are many differ...University hall is an important carrier of information exchange and sharing in higher education campuses,and the correct architectural design positioning can improve the value of university halls.There are many different features in the design and use of university halls and urban theaters.This paper investigates the feasibility study report and indexes of university hall projects,analyzes the indexes,construction scale and functional positioning of university halls in the pre-design period,summarizes some design suggestions,and believes that the use efficiency of university halls should be improved through intensive and compound construction to meet the needs of the rapid development of Chinas Universitys and universities.展开更多
The design of aircraft hydraulic pipeline system is limited by many factors,such as the integrity of aviation structure or narrow installation space,so the limited clamp support position should be considered.This pape...The design of aircraft hydraulic pipeline system is limited by many factors,such as the integrity of aviation structure or narrow installation space,so the limited clamp support position should be considered.This paper studied the frequency adjustment and dynamic responses reduction of the multi-support pipeline system through experiment and numerical simulation.To avoid the resonance of pipeline system,we proposed two different optimization programs,one was to avoid aero-engine working range,and another was to avoid aircraft hydraulic pump pulsation range.An optimization method was introduced in this paper to obtain the optimal clamp position.The experiments were introduced to validate the optimization results,and the theoretical optimization results can agree well with the test.With regard to avoiding the aero-engine vibration frequency,the test results revealed that the first natural frequency was far from the aero-engine vibration frequency.And the dynamic frequency sweep results showed that no resonance occurred on the pipeline in the engine vibration frequency range after optimization.Additionally,with regard to avoiding the pump vibration frequency,the test results revealed that natural frequencies have been adjusted and far from the pump vibration frequency.And the dynamic frequency sweep results showed that pipeline under optimal clamp position cannot lead to resonance.The sensitivity analysis results revealed the changing relationships between different clamp position and natural frequency.This study can provide helpful guidance on the analysis and design of practical aircraft pipeline.展开更多
The existing third-order tracker known as α-β-γ-δ filter has been used for target tracking and predicting for years. The filter can track the target's position and velocity, but not the acceleration. To extend it...The existing third-order tracker known as α-β-γ-δ filter has been used for target tracking and predicting for years. The filter can track the target's position and velocity, but not the acceleration. To extend its capability, a new fourth-order target tracker called α-β-γ-δ filter is proposed. The main objective of this study was to find the optimal set of filter parameters that leads to minimum position tracking errors. The tracking errors between using the α-β-γ-δ filter and the α-β-γ-δ filter are compared. As a result, the new filter exhibits significant improvement in position tracking accuracy over the existing third-order filter, but at the expense of computational time in search of the optimal filter. To reduce the computational time, a simulation-based optimization technique via Taguchi method is introduced.展开更多
This paper proposes a tube-based method for the asynchronous observation problem of discrete-time switched linear systems in the presence of amplitude-bounded disturbances.Sufficient stability conditions of the nomina...This paper proposes a tube-based method for the asynchronous observation problem of discrete-time switched linear systems in the presence of amplitude-bounded disturbances.Sufficient stability conditions of the nominal observer error system under mode-dependent persistent dwell-time(MPDT)switching are first established. Taking the disturbances into account, a novel asynchronous MPDT robust positive invariant(RPI) set and an asynchronous MPDT generalized RPI(GRPI)set are determined for the difference system between the nominal and disturbed observer error systems. Further, the global uniform asymptotical stability of the observer error system is established in the sense of converging to the asynchronous MPDT GRPI set, i.e., the cross section of the tube of the observer error system. Finally, the proposed results are validated on a space robot manipulator example.展开更多
The numbers of beam positions(BPs)and time slots for beam hopping(BH)dominate the latency of LEO satellite communications.Aiming at minimizing the number of BPs subject to a predefined requirement on the radius of BP,...The numbers of beam positions(BPs)and time slots for beam hopping(BH)dominate the latency of LEO satellite communications.Aiming at minimizing the number of BPs subject to a predefined requirement on the radius of BP,a low-complexity user density-based BP design scheme is proposed,where the original problem is decomposed into two subproblems,with the first one to find the sparsest user and the second one to determine the corresponding best BP.In particular,for the second subproblem,a user selection and smallest BP radius algorithm is proposed,where the nearby users are sequentially selected until the constraint of the given BP radius is no longer satisfied.These two subproblems are iteratively solved until all the users are selected.To further reduce the BP radius,a duplicated user removal algorithm is proposed to decrease the number of the users covered by two or more BPs.Aiming at minimizing the number of time slots subject to the no co-channel interference(CCI)constraint and the traffic demand constraint,a low-complexity CCI-free BH design scheme is proposed,where the BPs having difficulty in satisfying the constraints are considered to be illuminated in priory.Simulation results verify the effectiveness of the proposed schemes.展开更多
The construction of International Tourism Island has accelerated the development of Sanya City. The population aggregation and the external extension of urban area have brought a lot of negative effects, such as disco...The construction of International Tourism Island has accelerated the development of Sanya City. The population aggregation and the external extension of urban area have brought a lot of negative effects, such as discontinuities of green space matrix, dysfunction of green wedge permeation, deficiency of eco-corridor, structural imbalance of green space system and so on. The overall layout of Green space system known as "One Belt & Three Bays, One Core & Six Towns, Two Axes & Three Wedges, Two Net Synchronous-construction" strengthens the eco-connection among different groups and green space in central area of the city, and realizes the collaborative construction of both resource corridor and landscape corridor. The eco-layout of green core, green corridor and green patch helps keep the integrity of large vegetation patches, enhances the eco-connection of different types of green space and improves finger-shaped network of urban green space. The most efficient way to promote the circulation of urban ecosystem and the positive development of Sanya City is to plan multilevel and three-dimensional eco-space structure and maximize ecological benefits of green space system.展开更多
In order to reduce nursing intensity and improve freedom of the elderly and the disabled, a multi-function nursing wheelchair which can switch chair to bed and realize many kinds of posture transformation is designed....In order to reduce nursing intensity and improve freedom of the elderly and the disabled, a multi-function nursing wheelchair which can switch chair to bed and realize many kinds of posture transformation is designed. This paper introduces the mechanical structure design (position adjustment mechanism and variable wheelbase mechanism) and control design of posture transformation unit of multifunctional nursing wheelchair.展开更多
The angular position controller is system (EHSAS) to control the output of the rotary applied to electro-hydraulic servo actuator actuator. It works as a compensator based on the frequency response of the EHSAS. Its...The angular position controller is system (EHSAS) to control the output of the rotary applied to electro-hydraulic servo actuator actuator. It works as a compensator based on the frequency response of the EHSAS. Its design model is verified on the state-space model of EHSAS by using simulation program SIMULINK. Real data used to test the system. Simulation results give a good agreement for the controller and also for the state-space model.展开更多
Digitization precision analysis is an important tool to ensure the design precision of machine tool currently. The correlative research about precision modeling and analysis mainly focuses on the geometry precision an...Digitization precision analysis is an important tool to ensure the design precision of machine tool currently. The correlative research about precision modeling and analysis mainly focuses on the geometry precision and motion precision of machine tool, and the forming motion precision of workpiece surface. For the machine tool with complex forming motion, there is not accurate corresponding relationship between the existing criterion on precision design and the machining precision of workpiece. Therefore, a design scheme on machine tool precision based on error prediction is proposed, which is divided into two-stage digitization precision analysis crucially. The first stage aims at the technology system to complete the precision distribution and inspection from the workpiece to various component parts of technology system and achieve the total output precision of machine tool under the specified machining precision; the second stage aims at the machine tool system to complete the precision distribution and inspection from the output precision of machine tool to the machine tool components. This article serves YK3610 gear hobber as the example to describe the error model of two systems and basic application method, and the practical cutting precision of this machine tool achieves to 5-4-4 grade. The proposed method can provide reliable guidance to the precision design of machine tool with complex forming motion.展开更多
China Petroleum Design & Engineering Company (CPDEC) is a new corporation established in the year 2001. The company puts forward its development objectives for becoming a first-class national and international des...China Petroleum Design & Engineering Company (CPDEC) is a new corporation established in the year 2001. The company puts forward its development objectives for becoming a first-class national and international desigh firm within 5 to 10 years. In this paper, the theories and techniques related to the business environment and strategy are used to make an analysis of the companys development objectives. According to the analysis of the environment and internal conditions of CPDEC, we suggest adoping the strategic measures for reaching the development objectives on the basis of the SWOT (the acronym of Strengths, Weaknesses, Opportunities and Threats) analysis method. Some conclusions and recommendations on the companys situation and strategies are given.展开更多
In this study, the overall planning of Ji Townlet in Jianshan Town, Tujia-Miao Autonomous Prefecture was analyzed. The landscape planning & design of small townlets combined with the natural environment, humanist ...In this study, the overall planning of Ji Townlet in Jianshan Town, Tujia-Miao Autonomous Prefecture was analyzed. The landscape planning & design of small townlets combined with the natural environment, humanist resources and ethnic features in ethnic area were discussed.展开更多
In 2014, the National Association of Homebuilders conducted an initial survey about the use of Building Information Modeling (BIM) in residential construction. They found that BIM had not been widely adopted, but ther...In 2014, the National Association of Homebuilders conducted an initial survey about the use of Building Information Modeling (BIM) in residential construction. They found that BIM had not been widely adopted, but there was interest in future use. Four years later, the authors, Prof. Ghosh Dastider and Matt Jefferies at Washington University in St. Louis used a similar methodology to see what has changed. They found a significant increase in BIM’s application in the multifamily residential industry. Based on data collected from the re-conducted survey, the authors concluded with the future predictions on how use of BIM will accelerate in residential construction market in next few years. Few significant findings indicate increased use of BIM among contractors along with design built firms, as well as during the construction phase and life cycle analysis.展开更多
Liuzhou City is located in Guangxi Zhuang Autonomous Region of China. It has a warm and rainy climate and belongs to the middle subtropical monsoon climate. It is a rainstorm and flood-prone area. The work of flood dr...Liuzhou City is located in Guangxi Zhuang Autonomous Region of China. It has a warm and rainy climate and belongs to the middle subtropical monsoon climate. It is a rainstorm and flood-prone area. The work of flood drainage and waterlogging prevention is very important. The “minute to minute” rainfall process data of Liuzhou National Meteorological Observation Station from 1975 to 2014 and the Pilgrim & Cordery method were used to estimate the short-time design rainstorm profile of Liuzhou City, and the profiles of the rainfall lasting for 30, 60, 90, 120, 150, and 180 min were obtained. The research shows that the same rain duration and different recurrence period conditions are consistent with the rainstorm profile. The rainfall duration of 30, 60, 90, 120, and 180 min generally shows single-peak rainstorm profile, and the rainfall duration of 150 min shows double-peak rainstorm profile. Most peaks of each short-time design rainstorm profile are at or ahead of the 1/3 part of the entire rainfall process. During the same recurrence period, the rainfall in peak period fluctuated with the increase of the duration, and the intensity of rainfall increased with the prolonging of the recurrence period.展开更多
This paper gives an overview of studies on parameters displayed on the Automotive Head Up Display (A-HUD) including calculation and construction of symbology page based on study results. A study has been made on vit...This paper gives an overview of studies on parameters displayed on the Automotive Head Up Display (A-HUD) including calculation and construction of symbology page based on study results. A study has been made on vital parameters required for car drivers and design calculations have been made based on design parameters like field of view, distance from the design eye position, minimum character size viewable from a distance of 1.5m between driver and the projected image, and optical magnification factor. lhe display format suitable for A-HUD applications depends upon the parameters required to be displayed. The aspect ratio chosen is 4:3. This paper also provides method to design the symbology page embedding six vital parameters with their relative positioning and size considering relative position between display device and optical elements which has been considered with a magnification factor of 2.5. The field of view obtained is 6.7° × 4.8°.展开更多
This paper investigates systematically the problem of multivariate robustparameter design. First, a measurement criterion for the total variation of multivariate qualitycharacteristics is introduced by the result of i...This paper investigates systematically the problem of multivariate robustparameter design. First, a measurement criterion for the total variation of multivariate qualitycharacteristics is introduced by the result of information theory. Then the implementation procedurein the robust design is presented. After that, a simulation example from a practical industrialprocess is provided. Finally, some comments and further work are discussed.展开更多
基金Project(51071181)supported by the National Natural Science Foundation of ChinaProject(2013FJ4043)supported by the Natural Science Foundation of Hunan Province,China
文摘Taking Au?Cu system as an example, three discoveries and two methods were presented. First, a new way for boosting sustainable progress of systematic metal materials science (SMMS) and alloy gene engineering (AGE) is to establish holographic alloy positioning design (HAPD) system, of which the base consists of measurement and calculation center, SMMS center, AGE center, HAPD information center and HAPD cybernation center; Second, the resonance activating-sychro alternating mechanism of atom movement may be divided into the located and oriented diffuse modes; Third, the equilibrium and subequilibrium holographic network phase diagrams are blueprints and operable platform for researchers to discover, design, manufacture and deploy advanced alloys, which are obtained respectively by the equilibrium lever numerical method and cross point numerical method of isothermal Gibbs energy curves. As clicking each network point, the holographic information of three structure levels for the designed alloy may be readily obtained: the phase constitution and fraction, phase arranging structure and properties of organization; the composition, alloy gene arranging structure and properties of each phase and the electronic structures and properties of alloy genes. It will create a new era for network designing advanced alloys.
文摘BACKGROUND Neuroendoscopy is a very useful technique to Chronic Subdural Hematoma(CSH).But how to achieve the goal of treatment more minimally invasive?AIM To develop a simple,fast and accurate preoperative planning method in our way for endoscopic surgery of patients with CSH.METHODS From June 2018 to May 2020,forty-two patients with CSH,admitted to our hospital,were performed endoscopic minimally invasive surgery;computed tomography(CT)imaging was employed to locate the intracerebral hematoma and select the appropriate endoscopic approach before the endoscopic surgery.The clinical data and treatment efficacy were analyzed.RESULTS According to the learning of CT scanning images,the surgeon can accurately design the best minimally invasive neuroendoscopic surgical approach and realize the precise positioning and design of the drilling site of the skull and the size of the bone window,so as to provide the most effective operation space with the smallest bone window.In this group,the average operation time was only about 1 h,and the clearance rate of hematoma was about 95%.CONCLUSION Patients with CSH can achieve good therapeutic effect by using our way to positioning and design to assist the operation of CSH according to CT scan and image,and our way is very useful and necessary.
文摘Baseline observation as well as height measurement is the important content of the quality control of high-rise building construction.In order to strengthen the quality of construction projects,meet the requirement of completion time,improve the accuracy and efficiency of locating observation and explore a scientific way of observation suitable for high-rise building construction,this paper studies the design and implementation of high-rise building construction based on GPS positioning technology.
文摘The proper choice of optomechanical components along with alignment techniques is vital to the successful implementation of lens positioning and mounting. In general, there is a trade-off between lens positioning accuracy and manufacturing cost. In order to achieve optimal precision- to-cost ratio, a careful optomechanical design together with accurate alignment and assembly is necessary. This paper presents a lens positioning and mounting in a few microns accuracy using a kinematic mount module. The optomechanical design of the kinematic mount module and the associated fixtures based on the simulation study of components sensitivity are presented. The processes for alignment and assembly, which separate decenter from tip-tilt, are developed and presented. Finally, the prototypes are created and testing results are presented. The optomechanical design that allows the separation of decenter from tip-tilt considerably simplifies the positioning and assembly process and reduces the cost for mass production.
文摘University hall is an important carrier of information exchange and sharing in higher education campuses,and the correct architectural design positioning can improve the value of university halls.There are many different features in the design and use of university halls and urban theaters.This paper investigates the feasibility study report and indexes of university hall projects,analyzes the indexes,construction scale and functional positioning of university halls in the pre-design period,summarizes some design suggestions,and believes that the use efficiency of university halls should be improved through intensive and compound construction to meet the needs of the rapid development of Chinas Universitys and universities.
基金Supported by National Natural Science Foundation of China(Grant No.51875460)Aviation Power Foundation(Grant No.6141B090320)Foundation of Innovation and Creation for Graduate Students in Northwestern Ploytechnical University(Grant No.ZZ2019124).
文摘The design of aircraft hydraulic pipeline system is limited by many factors,such as the integrity of aviation structure or narrow installation space,so the limited clamp support position should be considered.This paper studied the frequency adjustment and dynamic responses reduction of the multi-support pipeline system through experiment and numerical simulation.To avoid the resonance of pipeline system,we proposed two different optimization programs,one was to avoid aero-engine working range,and another was to avoid aircraft hydraulic pump pulsation range.An optimization method was introduced in this paper to obtain the optimal clamp position.The experiments were introduced to validate the optimization results,and the theoretical optimization results can agree well with the test.With regard to avoiding the aero-engine vibration frequency,the test results revealed that the first natural frequency was far from the aero-engine vibration frequency.And the dynamic frequency sweep results showed that no resonance occurred on the pipeline in the engine vibration frequency range after optimization.Additionally,with regard to avoiding the pump vibration frequency,the test results revealed that natural frequencies have been adjusted and far from the pump vibration frequency.And the dynamic frequency sweep results showed that pipeline under optimal clamp position cannot lead to resonance.The sensitivity analysis results revealed the changing relationships between different clamp position and natural frequency.This study can provide helpful guidance on the analysis and design of practical aircraft pipeline.
文摘The existing third-order tracker known as α-β-γ-δ filter has been used for target tracking and predicting for years. The filter can track the target's position and velocity, but not the acceleration. To extend its capability, a new fourth-order target tracker called α-β-γ-δ filter is proposed. The main objective of this study was to find the optimal set of filter parameters that leads to minimum position tracking errors. The tracking errors between using the α-β-γ-δ filter and the α-β-γ-δ filter are compared. As a result, the new filter exhibits significant improvement in position tracking accuracy over the existing third-order filter, but at the expense of computational time in search of the optimal filter. To reduce the computational time, a simulation-based optimization technique via Taguchi method is introduced.
基金supported in part by the National Defense Basic Scientific Research Program of China(JCKY2018603C015)Cultivation Plan of Major Research Program of Harbin Institute of Technology(ZDXMPY20180101)
文摘This paper proposes a tube-based method for the asynchronous observation problem of discrete-time switched linear systems in the presence of amplitude-bounded disturbances.Sufficient stability conditions of the nominal observer error system under mode-dependent persistent dwell-time(MPDT)switching are first established. Taking the disturbances into account, a novel asynchronous MPDT robust positive invariant(RPI) set and an asynchronous MPDT generalized RPI(GRPI)set are determined for the difference system between the nominal and disturbed observer error systems. Further, the global uniform asymptotical stability of the observer error system is established in the sense of converging to the asynchronous MPDT GRPI set, i.e., the cross section of the tube of the observer error system. Finally, the proposed results are validated on a space robot manipulator example.
基金supported in part by National Key Research and Development Program of China under Grant 2021YFB2900404。
文摘The numbers of beam positions(BPs)and time slots for beam hopping(BH)dominate the latency of LEO satellite communications.Aiming at minimizing the number of BPs subject to a predefined requirement on the radius of BP,a low-complexity user density-based BP design scheme is proposed,where the original problem is decomposed into two subproblems,with the first one to find the sparsest user and the second one to determine the corresponding best BP.In particular,for the second subproblem,a user selection and smallest BP radius algorithm is proposed,where the nearby users are sequentially selected until the constraint of the given BP radius is no longer satisfied.These two subproblems are iteratively solved until all the users are selected.To further reduce the BP radius,a duplicated user removal algorithm is proposed to decrease the number of the users covered by two or more BPs.Aiming at minimizing the number of time slots subject to the no co-channel interference(CCI)constraint and the traffic demand constraint,a low-complexity CCI-free BH design scheme is proposed,where the BPs having difficulty in satisfying the constraints are considered to be illuminated in priory.Simulation results verify the effectiveness of the proposed schemes.
基金Sponsored by Hainan Provincial Natural Science Fund(411095)Hainan Provincial Philosophical and Social Science Planning Program(HNSK(JD)11-1)Sanya University-Local Goverment Science&Technology Cooperation Program(2013YD53)
文摘The construction of International Tourism Island has accelerated the development of Sanya City. The population aggregation and the external extension of urban area have brought a lot of negative effects, such as discontinuities of green space matrix, dysfunction of green wedge permeation, deficiency of eco-corridor, structural imbalance of green space system and so on. The overall layout of Green space system known as "One Belt & Three Bays, One Core & Six Towns, Two Axes & Three Wedges, Two Net Synchronous-construction" strengthens the eco-connection among different groups and green space in central area of the city, and realizes the collaborative construction of both resource corridor and landscape corridor. The eco-layout of green core, green corridor and green patch helps keep the integrity of large vegetation patches, enhances the eco-connection of different types of green space and improves finger-shaped network of urban green space. The most efficient way to promote the circulation of urban ecosystem and the positive development of Sanya City is to plan multilevel and three-dimensional eco-space structure and maximize ecological benefits of green space system.
基金Supported by NSFC(61170005)Special Topic of the Ministry of Education about Humanities and Social Sciences(12JDGC007)+2 种基金University Quality Project of Anhui Province(20100096)Graduate Education Reform Project of Hefei University of Technology(2011yjs003)National College Students' Training Project of Innovation and Entrepreneurship(201210359078)
文摘In order to reduce nursing intensity and improve freedom of the elderly and the disabled, a multi-function nursing wheelchair which can switch chair to bed and realize many kinds of posture transformation is designed. This paper introduces the mechanical structure design (position adjustment mechanism and variable wheelbase mechanism) and control design of posture transformation unit of multifunctional nursing wheelchair.
文摘The angular position controller is system (EHSAS) to control the output of the rotary applied to electro-hydraulic servo actuator actuator. It works as a compensator based on the frequency response of the EHSAS. Its design model is verified on the state-space model of EHSAS by using simulation program SIMULINK. Real data used to test the system. Simulation results give a good agreement for the controller and also for the state-space model.
基金supported by National Natural Science Foundation of China (Grant No. 51075419)Chongqing Municipal Natural Science Foundation of China (Grant No. CSTC,2009BB3234)
文摘Digitization precision analysis is an important tool to ensure the design precision of machine tool currently. The correlative research about precision modeling and analysis mainly focuses on the geometry precision and motion precision of machine tool, and the forming motion precision of workpiece surface. For the machine tool with complex forming motion, there is not accurate corresponding relationship between the existing criterion on precision design and the machining precision of workpiece. Therefore, a design scheme on machine tool precision based on error prediction is proposed, which is divided into two-stage digitization precision analysis crucially. The first stage aims at the technology system to complete the precision distribution and inspection from the workpiece to various component parts of technology system and achieve the total output precision of machine tool under the specified machining precision; the second stage aims at the machine tool system to complete the precision distribution and inspection from the output precision of machine tool to the machine tool components. This article serves YK3610 gear hobber as the example to describe the error model of two systems and basic application method, and the practical cutting precision of this machine tool achieves to 5-4-4 grade. The proposed method can provide reliable guidance to the precision design of machine tool with complex forming motion.
文摘China Petroleum Design & Engineering Company (CPDEC) is a new corporation established in the year 2001. The company puts forward its development objectives for becoming a first-class national and international desigh firm within 5 to 10 years. In this paper, the theories and techniques related to the business environment and strategy are used to make an analysis of the companys development objectives. According to the analysis of the environment and internal conditions of CPDEC, we suggest adoping the strategic measures for reaching the development objectives on the basis of the SWOT (the acronym of Strengths, Weaknesses, Opportunities and Threats) analysis method. Some conclusions and recommendations on the companys situation and strategies are given.
文摘In this study, the overall planning of Ji Townlet in Jianshan Town, Tujia-Miao Autonomous Prefecture was analyzed. The landscape planning & design of small townlets combined with the natural environment, humanist resources and ethnic features in ethnic area were discussed.
文摘In 2014, the National Association of Homebuilders conducted an initial survey about the use of Building Information Modeling (BIM) in residential construction. They found that BIM had not been widely adopted, but there was interest in future use. Four years later, the authors, Prof. Ghosh Dastider and Matt Jefferies at Washington University in St. Louis used a similar methodology to see what has changed. They found a significant increase in BIM’s application in the multifamily residential industry. Based on data collected from the re-conducted survey, the authors concluded with the future predictions on how use of BIM will accelerate in residential construction market in next few years. Few significant findings indicate increased use of BIM among contractors along with design built firms, as well as during the construction phase and life cycle analysis.
文摘Liuzhou City is located in Guangxi Zhuang Autonomous Region of China. It has a warm and rainy climate and belongs to the middle subtropical monsoon climate. It is a rainstorm and flood-prone area. The work of flood drainage and waterlogging prevention is very important. The “minute to minute” rainfall process data of Liuzhou National Meteorological Observation Station from 1975 to 2014 and the Pilgrim & Cordery method were used to estimate the short-time design rainstorm profile of Liuzhou City, and the profiles of the rainfall lasting for 30, 60, 90, 120, 150, and 180 min were obtained. The research shows that the same rain duration and different recurrence period conditions are consistent with the rainstorm profile. The rainfall duration of 30, 60, 90, 120, and 180 min generally shows single-peak rainstorm profile, and the rainfall duration of 150 min shows double-peak rainstorm profile. Most peaks of each short-time design rainstorm profile are at or ahead of the 1/3 part of the entire rainfall process. During the same recurrence period, the rainfall in peak period fluctuated with the increase of the duration, and the intensity of rainfall increased with the prolonging of the recurrence period.
文摘This paper gives an overview of studies on parameters displayed on the Automotive Head Up Display (A-HUD) including calculation and construction of symbology page based on study results. A study has been made on vital parameters required for car drivers and design calculations have been made based on design parameters like field of view, distance from the design eye position, minimum character size viewable from a distance of 1.5m between driver and the projected image, and optical magnification factor. lhe display format suitable for A-HUD applications depends upon the parameters required to be displayed. The aspect ratio chosen is 4:3. This paper also provides method to design the symbology page embedding six vital parameters with their relative positioning and size considering relative position between display device and optical elements which has been considered with a magnification factor of 2.5. The field of view obtained is 6.7° × 4.8°.
基金theNationalNaturalScienceFoundationofP.R.ChinaunderGrantNo. 79900018andNo.70372010, andbyAeronauticalScienceFoundationofP. R. ChinaunderGrantNo. 02J55001
文摘This paper investigates systematically the problem of multivariate robustparameter design. First, a measurement criterion for the total variation of multivariate qualitycharacteristics is introduced by the result of information theory. Then the implementation procedurein the robust design is presented. After that, a simulation example from a practical industrialprocess is provided. Finally, some comments and further work are discussed.