Large size titanium alloy parts are widely used in aerospace.However,they are difficult to manufacture using mechanical cutting technology because of severe tool wear.Electrochemical jet machining is a promising techn...Large size titanium alloy parts are widely used in aerospace.However,they are difficult to manufacture using mechanical cutting technology because of severe tool wear.Electrochemical jet machining is a promising technology to achieve high efficiency,because it has high machining flexibility and no machining tool wear.However,reports on the macro electrochemical jet machining of large size titanium alloy parts are very scarce,because it is difficult to achieve effective constraint of the flow field in macro electrochemical jet machining.In addition,titanium alloy is very sensitive to fluctuation of the flow field,and a turbulent flow field would lead to serious stray corrosion.This paper reports a series of investigations of the electrochemical jet machining of titanium alloy parts.Based on the flow analysis and experiments,the machining flow field was effectively constrained.TB6 titanium alloy part with a perimeter of one meter was machined.The machined surface was smooth with no obvious machining defects.The machining process was particularly stable with no obvious spark discharge.The research provides a reference for the application of electrochemical jet machining technology to achieve large allowance material removal in the machining of large titanium alloy parts.展开更多
In the face of data scarcity in the optimization of maintenance strategies for civil aircraft,traditional failure data-driven methods are encountering challenges owing to the increasing reliability of aircraft design....In the face of data scarcity in the optimization of maintenance strategies for civil aircraft,traditional failure data-driven methods are encountering challenges owing to the increasing reliability of aircraft design.This study addresses this issue by presenting a novel combined data fusion algorithm,which serves to enhance the accuracy and reliability of failure rate analysis for a specific aircraft model by integrating historical failure data from similar models as supplementary information.Through a comprehensive analysis of two different maintenance projects,this study illustrates the application process of the algorithm.Building upon the analysis results,this paper introduces the innovative equal integral value method as a replacement for the conventional equal interval method in the context of maintenance schedule optimization.The Monte Carlo simulation example validates that the equivalent essential value method surpasses the traditional method by over 20%in terms of inspection efficiency ratio.This discovery indicates that the equal critical value method not only upholds maintenance efficiency but also substantially decreases workload and maintenance costs.The findings of this study open up novel perspectives for airlines grappling with data scarcity,offer fresh strategies for the optimization of aviation maintenance practices,and chart a new course toward achieving more efficient and cost-effective maintenance schedule optimization through refined data analysis.展开更多
The aim of this study was to isolate the chemical constituents of the aerial parts of Polygala tenuifolia Willd. and to determine their antioxidant activities. Ten flavonoids were isolated and purified by silica gel, ...The aim of this study was to isolate the chemical constituents of the aerial parts of Polygala tenuifolia Willd. and to determine their antioxidant activities. Ten flavonoids were isolated and purified by silica gel, Sephadex LH-20, and ODS column chromatography, and semi-preparative HPLC. Their structures were elucidated by spectroscopic analysis and identified as isorhamnetin-3-O-13-D-glucopyranoside （1）, isorhamnetin-3-O-13-D-galactopyranoside （2）, quercetin-3-O-13-o-glucopyranosyl （1--＊2）-I^-D-galactopyranoside （3）, quercetin-3-O-13-O-glucopyranosyl （1---~2）-13-D-glucopyranoside （4）, linarin （5）, quercetin-3-O- 13-D-glucopyranoside （6）, 5,7-dihydroxy-8-methxoyflavone-7-O-13-o-glucuronoside （7）, isorhamnetin （8）, kaempferol （9） and quercetin （10）. All these compounds were isolated from this plant for the first time, and compounds 1-5 and 7 were isolated from the genus of Polygala for the first time. The antioxidant activities of the isolated compounds were evaluated by DPPH free radical scavenging assay, and compounds 3, 4, 6, 8, 9 and 10 showed potent antioxidant activities.展开更多
As a key technology of rapid prototyping and manufacturing (RP&M), rapid manufacturing of metal parts is a target of RP&M. Introducing selective laser sintering (SLS), an important branch of RP&M, this pap...As a key technology of rapid prototyping and manufacturing (RP&M), rapid manufacturing of metal parts is a target of RP&M. Introducing selective laser sintering (SLS), an important branch of RP&M, this paper gives a new method oriented on low power SLS system to fabricate metal parts. With this kind of technology, the mixture of metal and polymer powder is sintered first to get green part, then, after debinding and metal infiltration, dense parts are gotten. In the end, influencing factors of this technology are analyzed. At the same time, some applications are given.展开更多
This paper presents a mathematical model for components/parts unification (CPU) policy. This model considers two components/parts that are functionally interchangeable but purchased from suppliers with different price...This paper presents a mathematical model for components/parts unification (CPU) policy. This model considers two components/parts that are functionally interchangeable but purchased from suppliers with different prices and quality characteristics. Because of the buyer's quality preference and suppliers' discount rates for bulky purchases, the model assists the procurement manager to determine how best to purchase the components/parts to meet its demand while minimizing the total acquisition costs.展开更多
[Objective] This study was conducted to determinate the contents of poliumoside and forsythoside B in Callicarpa kwangtungensis,so as to reveal the distribution of two index components（poliumoside and forsythoside B...[Objective] This study was conducted to determinate the contents of poliumoside and forsythoside B in Callicarpa kwangtungensis,so as to reveal the distribution of two index components（poliumoside and forsythoside B） in the plant and to compare the contents of these components in the medicinal materials from different habitats.[Methods] Comparison and analysis of the contents of the two target components in different parts（root,branch,leaf and fruit） of Callicarpa kwangtungensis from the same habitat and in Callicarpa kwangtungensis from different production areas were performed according to the pharmacopoeia standard.[Result]The highest content of poliumoside wasdetected in fruit,and the content of forsythoside B was the highest in the branch.The contents of the two kinds of components were in order of branch fruit leafroot;The contents of the components were four times higher than China pharmacopeia（0.5%） in Jian,Tonggu,Anyuan,and Ganzhou of Jiangxi Province and the fifth area,Taijiang County of Qiandongnan Miao and Dong Autonomous Prefecture（QMDAP）,among which Ganzhou and Taijiang showed the highest contents.[Conclusion] The differences of poliumoside and forsythoside B were obvious in different habitats and different parts of Callicarpa kwangtungensis.展开更多
Based on an investigation on the current situation of SPM in some enterprises, this paper presents the common probletns and poor fields existing in SPM in enterprise; analyzes the reasons which resulted in the situati...Based on an investigation on the current situation of SPM in some enterprises, this paper presents the common probletns and poor fields existing in SPM in enterprise; analyzes the reasons which resulted in the situation, and then puts forward some feasible measures to improve it. Lastly, some fields that should be paid more attention in SPM are provided.展开更多
Due to the advantages of large workspace,low cost and the integrated vision/force sensing,robotic milling has become an important way for machining of complex parts.In recent years,many scholars have studied the probl...Due to the advantages of large workspace,low cost and the integrated vision/force sensing,robotic milling has become an important way for machining of complex parts.In recent years,many scholars have studied the problems existing in the applications of robotic milling,and lots of results have been made in the dynamics,pose planning,deformation control etc.,which provides theoretical guidance for high precision and high efficiency of robotic milling.From the perspective of complex parts robotic milling,this paper focuses on machining process planning and control techniques including the analysis of the robot-workspace,robot trajectory planning,vibration monitoring and control,deformation monitoring and compensation.As well as the principles of these technologies such as robot stiffness characteristics,dynamic characteristics,chatter mechanisms,and deformation mechanisms.The methods and characteristics related to the theory and technology of robotic milling of complex parts are summarized systematically.The latest research progress and achievements in the relevant fields are reviewed.It is hoped that the challenges,strategies and development related to robotic milling could be clarified through the carding work in this paper,so as to promote the application of related theories and technologies in high efficiency and precision intelligent milling with robot for complex parts.展开更多
In many fields of high-tech industry the ultra-t hi n wall parts are employed. In this paper the experiments were carried out to dis cuss the surface microstructure of the camera’s guided drawtube by applying ult ras...In many fields of high-tech industry the ultra-t hi n wall parts are employed. In this paper the experiments were carried out to dis cuss the surface microstructure of the camera’s guided drawtube by applying ult rasonic vibration cutting device to the traditional lathe. The influence rule of the cutting condition on the surface roughness was put forward, which was drawn by comparing the ultrasonic cutting with the common cutting by use of the cemen ted carbide tool and the polycrystalline diamond (PCD) tool. The test results sh owed that the ultrasonic cutting performs better than the common cutting in the same condition. According to the test results analyzing, the surface characteriz ation is influenced clearly by the rigidity of the acoustic system and the machi ne tool, as well the setting height of the tool tip. Otherwise, the dense regula r low frequency vibration ripples will be scraped on the machined surface. When the tool tip is set higher than the rotating center of the work piece by three t imes of the amplitude of ultrasonic vibration, the vibration ripples behave alig ht; they turn light and shade alternatively when the tool tip is lower than the rotating center of the work piece by three times of the amplitude of ultrasonic vibration. According to the test result analyzing, the following conclusions are put forward: 1) The surface roughness in ultrasonic cutting is better than that in common cutting. Under a one third critical cutting velocity, the value of th e surface roughness in ultrasonic cutting rise slightly along with the cutting v elocity, while in common cutting it decreases contrast to the cutting velocity; the curves of the surface roughness in ultrasonic cutting and common cutting see m to be alike, both increase along with the feed rate and the cutting depth, but the value in ultrasonic cutting is smaller in the same condition.2) The influen ce of the coolant on the surface roughness cannot be ignored. The kerosene can b e employed to improve the surface roughness in ultrasonic machining.3) In ultras onic cutting process of aluminum alloy ultra-thin wall work piece, the PCD tool performs better than the cemented carbide tools.4) The vibration ripples result from the not enough rigidity of the acoustic system and the improper setting he ight of the tool tip. The departure of the tool tip from the rotating center of the work piece to some extent causes the vibration ripples on the machined surfa ce.展开更多
In order to optimize the spares configuration project at different stages during the life cycle, the factor of time is considered to relax the assumption of the spares steady demand in multi-echelon technique for reco...In order to optimize the spares configuration project at different stages during the life cycle, the factor of time is considered to relax the assumption of the spares steady demand in multi-echelon technique for recoverable item control (METRIC) theory. According to the method of systems analysis, the dynamic palm theorem is introduced to establish the prediction model of the spares demand rate, and its main influence factors are analyzed, based on which, the spares support effectiveness evaluation index system is studied, and the system optimization-oriented spares dynamic configuration method for multi-echelon multi-indenture system is proposed. Through the analysis of the optimization algorithm, the layered marginal algorithm is designed to improve the model calculation efficiency. In a given example, the multi-stage spares configuration project during its life cycle is gotten, the research result conforms to the actual status, and it can provide a new way for the spares dynamic optimization.展开更多
A three-dimensional finite element model was established for the milling of thin-walled parts. The physical model of the milling of the part was established using the AdvantEdge FEM software as the platform. The alumi...A three-dimensional finite element model was established for the milling of thin-walled parts. The physical model of the milling of the part was established using the AdvantEdge FEM software as the platform. The aluminum alloy impeller was designated as the object to be processed and the boundary conditions which met the actual machining were set. Through the solution, the physical quantities such as the three-way cutting force, the tool temperature, and the tool stress were obtained, and the calculation of the elastic deformation of the thin-walled blade of the free-form surface at the contact points between the tool and the workpiece was realized. The elastic deformation law of the thin-walled blade was then predicted. The results show that the maximum deviation between the predicted value and the actual measured machining value of the elastic deformation was 26.055 μm; the minimum deviation was 2.011 μm, with the average deviation being 10.154 μm. This shows that the prediction is in close agreement with the actual result.展开更多
As a traditional Chinese herbal medicine exhibiting analgesic,fever-reducing and anti-inflammatory effects,Radix Bupleuri（Chai-Hu） is commonly used for the treatment of influenza,which is derived from the dried root...As a traditional Chinese herbal medicine exhibiting analgesic,fever-reducing and anti-inflammatory effects,Radix Bupleuri（Chai-Hu） is commonly used for the treatment of influenza,which is derived from the dried roots of Bupleurum chinense DC.and Bupleurum scorzonerifolium Willd.Among of diverse chemical components,saikosaponins are the key active components of the herb medicine.In the present study,we established a method of high performance liquid chromatography（HPLC） coupled with evaporative light scattering detection（ELSD） for simultaneous determination of saikosaponin a,c and d in root,stem,leaf and flower of Bupleurum chinense（B chinense） collected from different areas of Shanxi Province,China.The results from 16 samples of root,stem,leaf and flower of B chinense demonstrated that the total contents of the three saikosaponins in the root of B chinense collected from Dongshan Taiyuan,Xishan,Tianlongshan and Pangquangou were 4.26 mg/g,3.22 mg/g,4.23 mg/g and 3.05 mg/g,respectively.However,there was scarcely any saikosaponins in the stem,leaf and flower of B chinense collected from above-mentioned areas.The method of HPLC coupled with ELSD was suitable for quality control of Radix Bupleuri.The result also confirmed that the root of B chinense was the best medicinal part.展开更多
In the process of thin-wall parts assembly for an antenna,the parts assembly deformation deviation is occurring due to the riveting assembly.In view of the riveting assembly deformation problems,it can be analyzed thr...In the process of thin-wall parts assembly for an antenna,the parts assembly deformation deviation is occurring due to the riveting assembly.In view of the riveting assembly deformation problems,it can be analyzed through transient and static simulation.In this work,the theoretical deformation model for riveting assembly is established with round head rivet.The simulation analysis for riveting deformation is carried out with the riveting assembly piece including four rivets,which comparing with the measuring points experiment results of riveting test piece through dealing with the experimental data using the point coordinate transform method and the space line fitting method.Simultaneously,the deformation deviation of the overall thin-wall parts assembly structure is analyzed through finite element simulation;and its results are verified by the measuring experiment for riveting assembly with the deformation deviation of some key points on the thin-wall parts.Through the comparison analysis,it is shown that the simulation results agree well with the experimental results,which proves the correctness and effectiveness of the theoretical analysis,simulation results and the given experiment data processing method.Through the study on the riveting assembly for thin-wall parts,it will provide a theoretical foundation for improving thin-wall parts assembly quality of large antenna in future.展开更多
Revealing the development of microstructural inhomogeneity in the multi-pass flow forming of titanium alloy components is of great significance to the microstructure control and property tailoring.To this end,the micr...Revealing the development of microstructural inhomogeneity in the multi-pass flow forming of titanium alloy components is of great significance to the microstructure control and property tailoring.To this end,the microstructural inhomogeneity of TA15 alloy spun cylindrical parts was analyzed based on the deformation history.The results indicate that the material underwent significant compressive strain in the normal direction(ND),tension strain in the rolling and circumferential directions(RD and CD),while tension strain in the CD is slightly small due to the limited material flow in this direction.These strain characteristics make the microstructure,especially the primary a(ap),present different morphologies in the different planes of the part.Meanwhile,the combined effects of inhomogeneous deformation and temperature distribution in the ND also cause the inhomogeneity of microstructure morphology and parameters in this direction.Quantitative analyses show that with the forming pass increasing,the aspect ratio of apincreases most in the normal-rolling plane,then in the normal-circumferential plane and least in the circumferential-rolling plane,whereas apcontent decreases in an opposite trend.Along the ND,the aspect ratio and content of apis relatively high in the outer and inner surface areas but lowest in the central area,and these inhomogeneous characteristics can be gradually diminished with the forming pass increasing.Furthermore,the variation of hardness inhomogeneity factor indicates that a four-pass forming with the total reduction ratio of 63%could obtain a homogenous microstructure along the ND of the TA15 alloy spun cylindrical part.展开更多
Location layout of aircraft assembly is an important factor affecting product quality.Most of the existing re-searches use the combination of finite element analysis and intelligent algorithm to optimize the location ...Location layout of aircraft assembly is an important factor affecting product quality.Most of the existing re-searches use the combination of finite element analysis and intelligent algorithm to optimize the location layout,which are limited by numerical simulation accuracy and the selection and improvement of intelligent algorithms.At present,the analysis and decision-making technology based on field data is gradually applied in aircraft manufacturing.Based on the perception data of intelligent assembly unit of aircraft parts,a regression model of multi-input and multioutput support vector machine with Gauss kernel function as radial basis function is established,and the hyperparameters of the model are optimized by hybrid particle swarm optimization genetic algorithm(PSO-GA).GA-MSVR,PSO-MSVR and PSOGA-MSVR model are constructed respectively,and their results show that PSOGA-MSVR model has the best performance.Finally,the design of the aircraft wing location layout is taken as an example to verify the effectiveness of the method.展开更多
A novel technique of electroforming with orbital moving cathode was carried out for the fabrication of non-rotating thin-walled parts.This technique features a large number of insulating and insoluble hard particles a...A novel technique of electroforming with orbital moving cathode was carried out for the fabrication of non-rotating thin-walled parts.This technique features a large number of insulating and insoluble hard particles as a real-time polishing to the cathode.When cathode moves,hard particles polish its surface and provide the nickel non-rotating parts with near-mirror finishing.Morphology,microstructure,surface roughness and micro hardness of deposits fabricated by novel method were studied in contrast with the sample produced by traditional electroforming methods.Theoretical analysis and experimental results showed that the novel technique could effectively remove the hydrogen bubbles and nodules,disturb the crystal nucleation,and refine the grains of layer.The mechanical properties were significantly improved over traditional method.The micro-hardness of the layer was in a uniform distribution ranging from 345 HV to 360 HV.It was confirmed that this technique had practical significance to non-rotating thin-walled parts.展开更多
In equipment integrated logistics support(ILS), the supply capability of spare parts is a significant factor. There are lots of depots in the traditional support system, which makes too many redundant spare parts and ...In equipment integrated logistics support(ILS), the supply capability of spare parts is a significant factor. There are lots of depots in the traditional support system, which makes too many redundant spare parts and causes high cost of support. Meanwhile,the inconsistency among depots makes it difficult to manage spare parts. With the development of information technology and transportation, the supply network has become more efficient. In order to further improve the efficiency of supply-support work and the availability of the equipment system, building a system of one centralized depot with multiple depots becomes an appropriate way.In this case, location selection of the depots including centralized depots and multiple depots becomes a top priority in the support system. This paper will focus on the location selection problem of centralized depots considering ILS factors. Unlike the common location selection problem, depots in ILS require a higher service level. Therefore, it becomes desperately necessary to take the high requirement of the mission into account while determining location of depots. Based on this, we raise an optimal depot location model. First, the expected transportation cost is calculated.Next, factors in ILS such as response time, availability and fill rate are analyzed for evaluating positions of open depots. Then, an optimization model of depot location is developed with the minimum expected cost of transportation as objective and ILS factors as constraints. Finally, a numerical case is studied to prove the validity of the model by using the genetic algorithm. Results show that depot location obtained by this model can guarantee the effectiveness and capability of ILS well.展开更多
The inner hole parts played an oriented or supporting role in engineering machinery and equipment,which are prone to appear surface damages such as wear,strain and corrosion. The precise pulse plasma arc powder weldin...The inner hole parts played an oriented or supporting role in engineering machinery and equipment,which are prone to appear surface damages such as wear,strain and corrosion. The precise pulse plasma arc powder welding method is used for surface damage repairing of inner hole parts in this paper. The working principle and process of the technology are illustrated,and the microstructure and property of repairing layer by precise pulse plasma powder welding and CO2 gas shielded welding are tested and observed by microscope,micro hardness tester and X-ray residual stress tester etc. Results showed that the substrate deformation of thin-walled inner hole parts samples by precise pulse plasma powder welding is relatively small. The repair layer and substrate is metallurgical bonding,the transition zones( including fusion zone and heat affected zone) are relatively narrow and the welding quality is good. It showed that the thin-walled inner hole parts can be repaired by this technology and equipment.展开更多
基金the National Natural Science Foundation of China(No.52205468)China Postdoctoral Science Foundation(No.2022M710061 and No.2023T160277)Natural Science Foundation of Jiangsu Province(No.BK20210755)。
文摘Large size titanium alloy parts are widely used in aerospace.However,they are difficult to manufacture using mechanical cutting technology because of severe tool wear.Electrochemical jet machining is a promising technology to achieve high efficiency,because it has high machining flexibility and no machining tool wear.However,reports on the macro electrochemical jet machining of large size titanium alloy parts are very scarce,because it is difficult to achieve effective constraint of the flow field in macro electrochemical jet machining.In addition,titanium alloy is very sensitive to fluctuation of the flow field,and a turbulent flow field would lead to serious stray corrosion.This paper reports a series of investigations of the electrochemical jet machining of titanium alloy parts.Based on the flow analysis and experiments,the machining flow field was effectively constrained.TB6 titanium alloy part with a perimeter of one meter was machined.The machined surface was smooth with no obvious machining defects.The machining process was particularly stable with no obvious spark discharge.The research provides a reference for the application of electrochemical jet machining technology to achieve large allowance material removal in the machining of large titanium alloy parts.
文摘In the face of data scarcity in the optimization of maintenance strategies for civil aircraft,traditional failure data-driven methods are encountering challenges owing to the increasing reliability of aircraft design.This study addresses this issue by presenting a novel combined data fusion algorithm,which serves to enhance the accuracy and reliability of failure rate analysis for a specific aircraft model by integrating historical failure data from similar models as supplementary information.Through a comprehensive analysis of two different maintenance projects,this study illustrates the application process of the algorithm.Building upon the analysis results,this paper introduces the innovative equal integral value method as a replacement for the conventional equal interval method in the context of maintenance schedule optimization.The Monte Carlo simulation example validates that the equivalent essential value method surpasses the traditional method by over 20%in terms of inspection efficiency ratio.This discovery indicates that the equal critical value method not only upholds maintenance efficiency but also substantially decreases workload and maintenance costs.The findings of this study open up novel perspectives for airlines grappling with data scarcity,offer fresh strategies for the optimization of aviation maintenance practices,and chart a new course toward achieving more efficient and cost-effective maintenance schedule optimization through refined data analysis.
基金New-Century Talent Program, Ministry of Education of China (Grant No.985-2-102-113)National Science Fund for Excellent Young Scholars (Grant No. 81222051)National Key Technology R&D Program "New Drug Innovation" of China (Grant No. 2012ZX09304-005, 2012ZX09301002-002)
文摘The aim of this study was to isolate the chemical constituents of the aerial parts of Polygala tenuifolia Willd. and to determine their antioxidant activities. Ten flavonoids were isolated and purified by silica gel, Sephadex LH-20, and ODS column chromatography, and semi-preparative HPLC. Their structures were elucidated by spectroscopic analysis and identified as isorhamnetin-3-O-13-D-glucopyranoside （1）, isorhamnetin-3-O-13-D-galactopyranoside （2）, quercetin-3-O-13-o-glucopyranosyl （1--＊2）-I^-D-galactopyranoside （3）, quercetin-3-O-13-O-glucopyranosyl （1---~2）-13-D-glucopyranoside （4）, linarin （5）, quercetin-3-O- 13-D-glucopyranoside （6）, 5,7-dihydroxy-8-methxoyflavone-7-O-13-o-glucuronoside （7）, isorhamnetin （8）, kaempferol （9） and quercetin （10）. All these compounds were isolated from this plant for the first time, and compounds 1-5 and 7 were isolated from the genus of Polygala for the first time. The antioxidant activities of the isolated compounds were evaluated by DPPH free radical scavenging assay, and compounds 3, 4, 6, 8, 9 and 10 showed potent antioxidant activities.
文摘As a key technology of rapid prototyping and manufacturing (RP&M), rapid manufacturing of metal parts is a target of RP&M. Introducing selective laser sintering (SLS), an important branch of RP&M, this paper gives a new method oriented on low power SLS system to fabricate metal parts. With this kind of technology, the mixture of metal and polymer powder is sintered first to get green part, then, after debinding and metal infiltration, dense parts are gotten. In the end, influencing factors of this technology are analyzed. At the same time, some applications are given.
文摘This paper presents a mathematical model for components/parts unification (CPU) policy. This model considers two components/parts that are functionally interchangeable but purchased from suppliers with different prices and quality characteristics. Because of the buyer's quality preference and suppliers' discount rates for bulky purchases, the model assists the procurement manager to determine how best to purchase the components/parts to meet its demand while minimizing the total acquisition costs.
文摘[Objective] This study was conducted to determinate the contents of poliumoside and forsythoside B in Callicarpa kwangtungensis,so as to reveal the distribution of two index components（poliumoside and forsythoside B） in the plant and to compare the contents of these components in the medicinal materials from different habitats.[Methods] Comparison and analysis of the contents of the two target components in different parts（root,branch,leaf and fruit） of Callicarpa kwangtungensis from the same habitat and in Callicarpa kwangtungensis from different production areas were performed according to the pharmacopoeia standard.[Result]The highest content of poliumoside wasdetected in fruit,and the content of forsythoside B was the highest in the branch.The contents of the two kinds of components were in order of branch fruit leafroot;The contents of the components were four times higher than China pharmacopeia（0.5%） in Jian,Tonggu,Anyuan,and Ganzhou of Jiangxi Province and the fifth area,Taijiang County of Qiandongnan Miao and Dong Autonomous Prefecture（QMDAP）,among which Ganzhou and Taijiang showed the highest contents.[Conclusion] The differences of poliumoside and forsythoside B were obvious in different habitats and different parts of Callicarpa kwangtungensis.
文摘Based on an investigation on the current situation of SPM in some enterprises, this paper presents the common probletns and poor fields existing in SPM in enterprise; analyzes the reasons which resulted in the situation, and then puts forward some feasible measures to improve it. Lastly, some fields that should be paid more attention in SPM are provided.
基金supported by National Science Fund for Distinguished Young Scholars of China(No.51625502)Innovative Group Project of National Natural Science Foundation of China(No.51721092)Innovative Group Project of Hubei Province of China(No.2017CFA003)。
文摘Due to the advantages of large workspace,low cost and the integrated vision/force sensing,robotic milling has become an important way for machining of complex parts.In recent years,many scholars have studied the problems existing in the applications of robotic milling,and lots of results have been made in the dynamics,pose planning,deformation control etc.,which provides theoretical guidance for high precision and high efficiency of robotic milling.From the perspective of complex parts robotic milling,this paper focuses on machining process planning and control techniques including the analysis of the robot-workspace,robot trajectory planning,vibration monitoring and control,deformation monitoring and compensation.As well as the principles of these technologies such as robot stiffness characteristics,dynamic characteristics,chatter mechanisms,and deformation mechanisms.The methods and characteristics related to the theory and technology of robotic milling of complex parts are summarized systematically.The latest research progress and achievements in the relevant fields are reviewed.It is hoped that the challenges,strategies and development related to robotic milling could be clarified through the carding work in this paper,so as to promote the application of related theories and technologies in high efficiency and precision intelligent milling with robot for complex parts.
文摘In many fields of high-tech industry the ultra-t hi n wall parts are employed. In this paper the experiments were carried out to dis cuss the surface microstructure of the camera’s guided drawtube by applying ult rasonic vibration cutting device to the traditional lathe. The influence rule of the cutting condition on the surface roughness was put forward, which was drawn by comparing the ultrasonic cutting with the common cutting by use of the cemen ted carbide tool and the polycrystalline diamond (PCD) tool. The test results sh owed that the ultrasonic cutting performs better than the common cutting in the same condition. According to the test results analyzing, the surface characteriz ation is influenced clearly by the rigidity of the acoustic system and the machi ne tool, as well the setting height of the tool tip. Otherwise, the dense regula r low frequency vibration ripples will be scraped on the machined surface. When the tool tip is set higher than the rotating center of the work piece by three t imes of the amplitude of ultrasonic vibration, the vibration ripples behave alig ht; they turn light and shade alternatively when the tool tip is lower than the rotating center of the work piece by three times of the amplitude of ultrasonic vibration. According to the test result analyzing, the following conclusions are put forward: 1) The surface roughness in ultrasonic cutting is better than that in common cutting. Under a one third critical cutting velocity, the value of th e surface roughness in ultrasonic cutting rise slightly along with the cutting v elocity, while in common cutting it decreases contrast to the cutting velocity; the curves of the surface roughness in ultrasonic cutting and common cutting see m to be alike, both increase along with the feed rate and the cutting depth, but the value in ultrasonic cutting is smaller in the same condition.2) The influen ce of the coolant on the surface roughness cannot be ignored. The kerosene can b e employed to improve the surface roughness in ultrasonic machining.3) In ultras onic cutting process of aluminum alloy ultra-thin wall work piece, the PCD tool performs better than the cemented carbide tools.4) The vibration ripples result from the not enough rigidity of the acoustic system and the improper setting he ight of the tool tip. The departure of the tool tip from the rotating center of the work piece to some extent causes the vibration ripples on the machined surfa ce.
基金supported by the National Defense Pre-research Project in 13th Five-Year(41404050502)the National Defense Science and Technology Fund of the Central Military Commission(2101140)
文摘In order to optimize the spares configuration project at different stages during the life cycle, the factor of time is considered to relax the assumption of the spares steady demand in multi-echelon technique for recoverable item control (METRIC) theory. According to the method of systems analysis, the dynamic palm theorem is introduced to establish the prediction model of the spares demand rate, and its main influence factors are analyzed, based on which, the spares support effectiveness evaluation index system is studied, and the system optimization-oriented spares dynamic configuration method for multi-echelon multi-indenture system is proposed. Through the analysis of the optimization algorithm, the layered marginal algorithm is designed to improve the model calculation efficiency. In a given example, the multi-stage spares configuration project during its life cycle is gotten, the research result conforms to the actual status, and it can provide a new way for the spares dynamic optimization.
基金Project(U1530138)supported by the National Natural Science Foundation of ChinaProject(A1-8903-17-0103)supported by the Natural Science Foundation of Shanghai Municipal Education Commission,China
文摘A three-dimensional finite element model was established for the milling of thin-walled parts. The physical model of the milling of the part was established using the AdvantEdge FEM software as the platform. The aluminum alloy impeller was designated as the object to be processed and the boundary conditions which met the actual machining were set. Through the solution, the physical quantities such as the three-way cutting force, the tool temperature, and the tool stress were obtained, and the calculation of the elastic deformation of the thin-walled blade of the free-form surface at the contact points between the tool and the workpiece was realized. The elastic deformation law of the thin-walled blade was then predicted. The results show that the maximum deviation between the predicted value and the actual measured machining value of the elastic deformation was 26.055 μm; the minimum deviation was 2.011 μm, with the average deviation being 10.154 μm. This shows that the prediction is in close agreement with the actual result.
基金Shanxi Educational Committee(Grant No.20111113)Shanxi Science and Technology Department(Grant No.2016ZD0201)
文摘As a traditional Chinese herbal medicine exhibiting analgesic,fever-reducing and anti-inflammatory effects,Radix Bupleuri（Chai-Hu） is commonly used for the treatment of influenza,which is derived from the dried roots of Bupleurum chinense DC.and Bupleurum scorzonerifolium Willd.Among of diverse chemical components,saikosaponins are the key active components of the herb medicine.In the present study,we established a method of high performance liquid chromatography（HPLC） coupled with evaporative light scattering detection（ELSD） for simultaneous determination of saikosaponin a,c and d in root,stem,leaf and flower of Bupleurum chinense（B chinense） collected from different areas of Shanxi Province,China.The results from 16 samples of root,stem,leaf and flower of B chinense demonstrated that the total contents of the three saikosaponins in the root of B chinense collected from Dongshan Taiyuan,Xishan,Tianlongshan and Pangquangou were 4.26 mg/g,3.22 mg/g,4.23 mg/g and 3.05 mg/g,respectively.However,there was scarcely any saikosaponins in the stem,leaf and flower of B chinense collected from above-mentioned areas.The method of HPLC coupled with ELSD was suitable for quality control of Radix Bupleuri.The result also confirmed that the root of B chinense was the best medicinal part.
基金Project(51675100)supported by the National Natural Science Foundation of ChinaProject(2016ZX04004008)supported by the National Numerical Control Equipment Major Project of ChinaProject(6902002116)supported by the Foundation of Certain Ministry of China
文摘In the process of thin-wall parts assembly for an antenna,the parts assembly deformation deviation is occurring due to the riveting assembly.In view of the riveting assembly deformation problems,it can be analyzed through transient and static simulation.In this work,the theoretical deformation model for riveting assembly is established with round head rivet.The simulation analysis for riveting deformation is carried out with the riveting assembly piece including four rivets,which comparing with the measuring points experiment results of riveting test piece through dealing with the experimental data using the point coordinate transform method and the space line fitting method.Simultaneously,the deformation deviation of the overall thin-wall parts assembly structure is analyzed through finite element simulation;and its results are verified by the measuring experiment for riveting assembly with the deformation deviation of some key points on the thin-wall parts.Through the comparison analysis,it is shown that the simulation results agree well with the experimental results,which proves the correctness and effectiveness of the theoretical analysis,simulation results and the given experiment data processing method.Through the study on the riveting assembly for thin-wall parts,it will provide a theoretical foundation for improving thin-wall parts assembly quality of large antenna in future.
基金the financial support from the National Science Fund for Distinguished Young Scholars of China(No.51625505)the Key Program Project of the Joint Fund of Astronomy and National Natural Science Foundation of China(No.U1537203)+1 种基金National Natural Science Foundation of China(No.51875467)the support of Young Elite Scientists Sponsorship Program by CAST of China(No.2018QNRC001)。
文摘Revealing the development of microstructural inhomogeneity in the multi-pass flow forming of titanium alloy components is of great significance to the microstructure control and property tailoring.To this end,the microstructural inhomogeneity of TA15 alloy spun cylindrical parts was analyzed based on the deformation history.The results indicate that the material underwent significant compressive strain in the normal direction(ND),tension strain in the rolling and circumferential directions(RD and CD),while tension strain in the CD is slightly small due to the limited material flow in this direction.These strain characteristics make the microstructure,especially the primary a(ap),present different morphologies in the different planes of the part.Meanwhile,the combined effects of inhomogeneous deformation and temperature distribution in the ND also cause the inhomogeneity of microstructure morphology and parameters in this direction.Quantitative analyses show that with the forming pass increasing,the aspect ratio of apincreases most in the normal-rolling plane,then in the normal-circumferential plane and least in the circumferential-rolling plane,whereas apcontent decreases in an opposite trend.Along the ND,the aspect ratio and content of apis relatively high in the outer and inner surface areas but lowest in the central area,and these inhomogeneous characteristics can be gradually diminished with the forming pass increasing.Furthermore,the variation of hardness inhomogeneity factor indicates that a four-pass forming with the total reduction ratio of 63%could obtain a homogenous microstructure along the ND of the TA15 alloy spun cylindrical part.
基金supported by the Equipment Pre-research Project of China (No. 41423010202)
文摘Location layout of aircraft assembly is an important factor affecting product quality.Most of the existing re-searches use the combination of finite element analysis and intelligent algorithm to optimize the location layout,which are limited by numerical simulation accuracy and the selection and improvement of intelligent algorithms.At present,the analysis and decision-making technology based on field data is gradually applied in aircraft manufacturing.Based on the perception data of intelligent assembly unit of aircraft parts,a regression model of multi-input and multioutput support vector machine with Gauss kernel function as radial basis function is established,and the hyperparameters of the model are optimized by hybrid particle swarm optimization genetic algorithm(PSO-GA).GA-MSVR,PSO-MSVR and PSOGA-MSVR model are constructed respectively,and their results show that PSOGA-MSVR model has the best performance.Finally,the design of the aircraft wing location layout is taken as an example to verify the effectiveness of the method.
基金Funded partly by the National Natural Science Foundation of China(No.50975143)the Aviation Science Funds,China (No.2009ZE52048)
文摘A novel technique of electroforming with orbital moving cathode was carried out for the fabrication of non-rotating thin-walled parts.This technique features a large number of insulating and insoluble hard particles as a real-time polishing to the cathode.When cathode moves,hard particles polish its surface and provide the nickel non-rotating parts with near-mirror finishing.Morphology,microstructure,surface roughness and micro hardness of deposits fabricated by novel method were studied in contrast with the sample produced by traditional electroforming methods.Theoretical analysis and experimental results showed that the novel technique could effectively remove the hydrogen bubbles and nodules,disturb the crystal nucleation,and refine the grains of layer.The mechanical properties were significantly improved over traditional method.The micro-hardness of the layer was in a uniform distribution ranging from 345 HV to 360 HV.It was confirmed that this technique had practical significance to non-rotating thin-walled parts.
基金supported by the Science Challenge Project(TZ2018007)the National Natural Science Foundation of China(71671009+2 种基金 61871013 61573041 61573043)
文摘In equipment integrated logistics support(ILS), the supply capability of spare parts is a significant factor. There are lots of depots in the traditional support system, which makes too many redundant spare parts and causes high cost of support. Meanwhile,the inconsistency among depots makes it difficult to manage spare parts. With the development of information technology and transportation, the supply network has become more efficient. In order to further improve the efficiency of supply-support work and the availability of the equipment system, building a system of one centralized depot with multiple depots becomes an appropriate way.In this case, location selection of the depots including centralized depots and multiple depots becomes a top priority in the support system. This paper will focus on the location selection problem of centralized depots considering ILS factors. Unlike the common location selection problem, depots in ILS require a higher service level. Therefore, it becomes desperately necessary to take the high requirement of the mission into account while determining location of depots. Based on this, we raise an optimal depot location model. First, the expected transportation cost is calculated.Next, factors in ILS such as response time, availability and fill rate are analyzed for evaluating positions of open depots. Then, an optimization model of depot location is developed with the minimum expected cost of transportation as objective and ILS factors as constraints. Finally, a numerical case is studied to prove the validity of the model by using the genetic algorithm. Results show that depot location obtained by this model can guarantee the effectiveness and capability of ILS well.
文摘The inner hole parts played an oriented or supporting role in engineering machinery and equipment,which are prone to appear surface damages such as wear,strain and corrosion. The precise pulse plasma arc powder welding method is used for surface damage repairing of inner hole parts in this paper. The working principle and process of the technology are illustrated,and the microstructure and property of repairing layer by precise pulse plasma powder welding and CO2 gas shielded welding are tested and observed by microscope,micro hardness tester and X-ray residual stress tester etc. Results showed that the substrate deformation of thin-walled inner hole parts samples by precise pulse plasma powder welding is relatively small. The repair layer and substrate is metallurgical bonding,the transition zones( including fusion zone and heat affected zone) are relatively narrow and the welding quality is good. It showed that the thin-walled inner hole parts can be repaired by this technology and equipment.
