Straight-line compliant mechanisms are important building blocks to design a linear-motion stage, which is very useful in precision applications. However, only a few configurations of straight-line compliant mechanism...Straight-line compliant mechanisms are important building blocks to design a linear-motion stage, which is very useful in precision applications. However, only a few configurations of straight-line compliant mechanisms are applicable. To construct more kinds of them, an approach to design large-displacement straight-line flexural mechanisms with rotational flexural joints is proposed, which is based on a viewpoint that the straight-line motion is regarded as a compromise of rigid and compliant parasitic motion of a rotational flexural joint. An analytical design method based on the Taylor series expansion is proposed to quickly obtain an approximate solution. To illustrate and verify the proposed method, two kinds of flexural joints, cross-axis hinge and leaf-type isosceles-trapezoidal flexural（LITF） pivot are used to reconstruct straight-line flexural mechanisms. Their performances are obtained by analytic and FEA method respectively. The comparisons of the results show the accuracy of the approach. Both examples show that the proposed approach can convert a large-deflection flexural joint into approximate straight-line mechanism with a high linearity that is higher than 5 000 within 5 man displacement. This can lead to a new way to design, analyze or optimize straight-line flexure mechanisms.展开更多
In order to solve four-bar straight-line guidance mechanism synthesis problem for the arbitrarily given straight-line’s"angle requirement"and"point-position requirement",a numerical comparison syn...In order to solve four-bar straight-line guidance mechanism synthesis problem for the arbitrarily given straight-line’s"angle requirement"and"point-position requirement",a numerical comparison synthesis method for single and double straight-line guidance mechanism is presented,which is convenient to realize by computer program.The basic idea of this method is:to select a four-bar linkage whose relative bar length of crank is 1 as a basic four-bar linkage.Then the other three relative bars’length is changed,and a lot of basic four-bar linkage can be obtained.There are many single and double ball-points of each basic four-bar linkage.With the motion of a basic four-bar linkage,there is straight-line segment of each Ball-point’s path.The data of these basic four-bar linkages is saved to a database.When designing a four-bar straight-line guidance mechanism,the design data is compared with the data in database and a satisfactory four-bar linkage can be obtained.The method effectively solves the straight-line guidance mechanism synthesis problem.展开更多
The straight-line method in computing for depreciation expense is the prevailing method used in the Philippines. This paper aims to determine the rationale behind the use of this method. The objective of the study is ...The straight-line method in computing for depreciation expense is the prevailing method used in the Philippines. This paper aims to determine the rationale behind the use of this method. The objective of the study is to determine the length of time within which the depreciation method is used, reasons in using the method, the rate of depreciation used by the companies, and the effects of the depreciation expense on their operating expenses. It also determines if the companies＇ decisions to use the straight-line method are influenced by the factors mentioned by Reynolds （196 I）----expected amount of services over the life of assets, the amount and timing of operating costs, the decline in the physical efficiency of the assets, and the rate of return--and if they considered capital investments and tax reduction in using this method. The study shows that companies and educational institutions use the straight-line method of computing depreciation expenses, because it is easy to use in computing the depreciation expenses, in comparing with previous years＇ computations, and in keeping track of the expenses. It is also convenient for tax administration and financial reporting. The rate of depreciation used varies, because the companies and educational institutions use their past experiences in determining the life of fixed assets. The percentage of depreciation to the operating expenses also varies. The companies and educational institutions adhered to the factors mentioned by Reynolds （1961） in choosing the straight-line method of depreciation. The companies did not consider reduction of tax in using the straight-line method.展开更多
·AIM: To introduce a new technique for iridoschisis management during phacoemulsification: “capsule drape wrap”.·METHODS: “Capsule drape wrap” technique was used for an 80-year-old man with idiopathic ir...·AIM: To introduce a new technique for iridoschisis management during phacoemulsification: “capsule drape wrap”.·METHODS: “Capsule drape wrap” technique was used for an 80-year-old man with idiopathic iridoschisis in the right eye during phacoemulsification. The inserted flexible nylon iris hooks to hold anterior capsule in place, the margin of the anterior capsule could act as drape wrap, tracking the fibrillary iris strands firmly from free floating and stabilizing the capsular bags simultaneously. ·RESULTS: The eye with iridoschisis was successfully treated. Iris fibrils remained immobile during the procedure, and despite the severity of iridoschisis, there were no intraoperative complications such as tear of the iris, hyphema, iris prolapse, loss of mydriasis, or rupture of the posterior lens capsule during phacoemulsification. The bestcorrected visual acuity was increased by 0.1(log MAR) 6mo after the surgery.·CONCLUSION: “Capsule drape wrap” for iridoschisis is easily manageable, prevents further disruption to the loose iris fibers and ensures the stability of capsule–iris complex simultaneously, consequently minimizing the risk of surgical complications in phacoemulsification.展开更多
On the backdrop of dwindling conventional reserves,unconventional reservoirs have emerged as a pivotal chapter in resource extraction.Despite their challenges,such as low permeability,complex fluid storage,and flow me...On the backdrop of dwindling conventional reserves,unconventional reservoirs have emerged as a pivotal chapter in resource extraction.Despite their challenges,such as low permeability,complex fluid storage,and flow mechanisms,hydraulic fracturing technology has underpinned the development of unconventional reservoirs.Consequently,this has brought about a shift in the sequence of flow regimes,e.g.,the transient radial flow regime has been largely shortened by the lengthy transient linear flow regime due to the low permeability of unconventional reservoirs.Moreover,straight-line analysis(SLA),the simplest technique in rate transient analysis(RTA),is a fundamental and potent tool for swiftly extracting reservoir and hydraulic fracture information,estimating oil and gas reserves,and furnishing crucial initial data for subsequent historical matching processes.However,there is currently a dearth of review papers pertaining to a necessary guide of applying SLA in various transient linear flow(TLF)regimes and different unconventional reservoirs.Hence,this paper commences by elucidating the classification of TLF regimes,commonly used methods for recognizing flow regimes,and the diverse SLA methods used for different TLF regimes.Subsequently,it delves into a discussion of different modification techniques for variable rate/flowing pressure,gas phase,complex reservoir characteristics in unconventional reservoirs,and dynamic drainage area concepts etc.Furthermore,the application of SLA in specific domains,namely core analysis and the flowback period,is described.It culminates by surveying the advancements through an integration of novel technologies to enhance estimation accuracy.The paper also highlights certain drawbacks of current SLA technology and proposes new research directions.Ultimately,this paper would serve as an indispensable resource,offering foundational knowledge for the application of SLA in TLF to promote the production of global unconventional resources in a cost-effective and environmentally sustainable fashion in the face of a climate-resilient world.展开更多
On the basis of our previous research work, an expressing index was proposed for the lively degree of dynamic fabric drape. Meanwhile, the main factor analysis for parameters of fabric drape was applied and the 5 main...On the basis of our previous research work, an expressing index was proposed for the lively degree of dynamic fabric drape. Meanwhile, the main factor analysis for parameters of fabric drape was applied and the 5 main factors, comprehensive indexes of expressing aesthetics of fabric drape, were obtained. Through the scored diagrams of main factors of fabric drape aesthetics, 100 kinds of fabric samples could be identified and catalogued. A new method was found out for the objective evaluation of aesthetics of fabric drape.展开更多
The performance of image-analysis-based drape tester is studied by analyzing the testing results. The accelerating and decelerating method is used to make the initial testing condition same before draping. A feature v...The performance of image-analysis-based drape tester is studied by analyzing the testing results. The accelerating and decelerating method is used to make the initial testing condition same before draping. A feature vector is proposed to describe the drapenbility of fabrics comprehensively. Moreover, the exponential relationship curves between drape coefficient and rotating speed are obtained from the drape tester to describe the dynamic drapeability Finally, the stability of tested results of image-analysis-based system is studied.展开更多
This paper introduces a new method of measuring the three-dimensional drape shape of fabrics with structural light. First, we apply parallel annular structural light to form light and shade alternating contour stripes...This paper introduces a new method of measuring the three-dimensional drape shape of fabrics with structural light. First, we apply parallel annular structural light to form light and shade alternating contour stripes on the surface of fabrics. We then collect the images of contour stripes using Charge Coupled Device (CCD). Subsequently, we process the images to identify the contour stripes and edges of fabrics, and obtain the fabric contour lines of curved surfaces. Finally, we apply three-dimensional curved surface modeling method based on a network of polar coordinates, and reconstruct the three-dimensional drape shape of fabrics. Experiments show that our method is effective in testing and reconstructing three-dimensional drape shape of fabrics.展开更多
基金supported by National Natural Science Foundation of China(Grant No.51275552)Foundation for the Author of National Excellent Doctoral Dissertation of China(Grant No.201234)
文摘Straight-line compliant mechanisms are important building blocks to design a linear-motion stage, which is very useful in precision applications. However, only a few configurations of straight-line compliant mechanisms are applicable. To construct more kinds of them, an approach to design large-displacement straight-line flexural mechanisms with rotational flexural joints is proposed, which is based on a viewpoint that the straight-line motion is regarded as a compromise of rigid and compliant parasitic motion of a rotational flexural joint. An analytical design method based on the Taylor series expansion is proposed to quickly obtain an approximate solution. To illustrate and verify the proposed method, two kinds of flexural joints, cross-axis hinge and leaf-type isosceles-trapezoidal flexural（LITF） pivot are used to reconstruct straight-line flexural mechanisms. Their performances are obtained by analytic and FEA method respectively. The comparisons of the results show the accuracy of the approach. Both examples show that the proposed approach can convert a large-deflection flexural joint into approximate straight-line mechanism with a high linearity that is higher than 5 000 within 5 man displacement. This can lead to a new way to design, analyze or optimize straight-line flexure mechanisms.
文摘In order to solve four-bar straight-line guidance mechanism synthesis problem for the arbitrarily given straight-line’s"angle requirement"and"point-position requirement",a numerical comparison synthesis method for single and double straight-line guidance mechanism is presented,which is convenient to realize by computer program.The basic idea of this method is:to select a four-bar linkage whose relative bar length of crank is 1 as a basic four-bar linkage.Then the other three relative bars’length is changed,and a lot of basic four-bar linkage can be obtained.There are many single and double ball-points of each basic four-bar linkage.With the motion of a basic four-bar linkage,there is straight-line segment of each Ball-point’s path.The data of these basic four-bar linkages is saved to a database.When designing a four-bar straight-line guidance mechanism,the design data is compared with the data in database and a satisfactory four-bar linkage can be obtained.The method effectively solves the straight-line guidance mechanism synthesis problem.
文摘The straight-line method in computing for depreciation expense is the prevailing method used in the Philippines. This paper aims to determine the rationale behind the use of this method. The objective of the study is to determine the length of time within which the depreciation method is used, reasons in using the method, the rate of depreciation used by the companies, and the effects of the depreciation expense on their operating expenses. It also determines if the companies＇ decisions to use the straight-line method are influenced by the factors mentioned by Reynolds （196 I）----expected amount of services over the life of assets, the amount and timing of operating costs, the decline in the physical efficiency of the assets, and the rate of return--and if they considered capital investments and tax reduction in using this method. The study shows that companies and educational institutions use the straight-line method of computing depreciation expenses, because it is easy to use in computing the depreciation expenses, in comparing with previous years＇ computations, and in keeping track of the expenses. It is also convenient for tax administration and financial reporting. The rate of depreciation used varies, because the companies and educational institutions use their past experiences in determining the life of fixed assets. The percentage of depreciation to the operating expenses also varies. The companies and educational institutions adhered to the factors mentioned by Reynolds （1961） in choosing the straight-line method of depreciation. The companies did not consider reduction of tax in using the straight-line method.
基金Supported by the National Key R&D Program of China (No.2020YFC2008202)the National Natural Science Foundation of China (No.81970813)+1 种基金the Natural Science Foundation of Guangdong Province (No.2023A1515011198)Guangzhou Municipal Science and Technology Project (No.SL2022A03J00553)。
文摘·AIM: To introduce a new technique for iridoschisis management during phacoemulsification: “capsule drape wrap”.·METHODS: “Capsule drape wrap” technique was used for an 80-year-old man with idiopathic iridoschisis in the right eye during phacoemulsification. The inserted flexible nylon iris hooks to hold anterior capsule in place, the margin of the anterior capsule could act as drape wrap, tracking the fibrillary iris strands firmly from free floating and stabilizing the capsular bags simultaneously. ·RESULTS: The eye with iridoschisis was successfully treated. Iris fibrils remained immobile during the procedure, and despite the severity of iridoschisis, there were no intraoperative complications such as tear of the iris, hyphema, iris prolapse, loss of mydriasis, or rupture of the posterior lens capsule during phacoemulsification. The bestcorrected visual acuity was increased by 0.1(log MAR) 6mo after the surgery.·CONCLUSION: “Capsule drape wrap” for iridoschisis is easily manageable, prevents further disruption to the loose iris fibers and ensures the stability of capsule–iris complex simultaneously, consequently minimizing the risk of surgical complications in phacoemulsification.
基金support from the China Scholarship Council(CSC)the University of Calgary.
文摘On the backdrop of dwindling conventional reserves,unconventional reservoirs have emerged as a pivotal chapter in resource extraction.Despite their challenges,such as low permeability,complex fluid storage,and flow mechanisms,hydraulic fracturing technology has underpinned the development of unconventional reservoirs.Consequently,this has brought about a shift in the sequence of flow regimes,e.g.,the transient radial flow regime has been largely shortened by the lengthy transient linear flow regime due to the low permeability of unconventional reservoirs.Moreover,straight-line analysis(SLA),the simplest technique in rate transient analysis(RTA),is a fundamental and potent tool for swiftly extracting reservoir and hydraulic fracture information,estimating oil and gas reserves,and furnishing crucial initial data for subsequent historical matching processes.However,there is currently a dearth of review papers pertaining to a necessary guide of applying SLA in various transient linear flow(TLF)regimes and different unconventional reservoirs.Hence,this paper commences by elucidating the classification of TLF regimes,commonly used methods for recognizing flow regimes,and the diverse SLA methods used for different TLF regimes.Subsequently,it delves into a discussion of different modification techniques for variable rate/flowing pressure,gas phase,complex reservoir characteristics in unconventional reservoirs,and dynamic drainage area concepts etc.Furthermore,the application of SLA in specific domains,namely core analysis and the flowback period,is described.It culminates by surveying the advancements through an integration of novel technologies to enhance estimation accuracy.The paper also highlights certain drawbacks of current SLA technology and proposes new research directions.Ultimately,this paper would serve as an indispensable resource,offering foundational knowledge for the application of SLA in TLF to promote the production of global unconventional resources in a cost-effective and environmentally sustainable fashion in the face of a climate-resilient world.
文摘On the basis of our previous research work, an expressing index was proposed for the lively degree of dynamic fabric drape. Meanwhile, the main factor analysis for parameters of fabric drape was applied and the 5 main factors, comprehensive indexes of expressing aesthetics of fabric drape, were obtained. Through the scored diagrams of main factors of fabric drape aesthetics, 100 kinds of fabric samples could be identified and catalogued. A new method was found out for the objective evaluation of aesthetics of fabric drape.
文摘The performance of image-analysis-based drape tester is studied by analyzing the testing results. The accelerating and decelerating method is used to make the initial testing condition same before draping. A feature vector is proposed to describe the drapenbility of fabrics comprehensively. Moreover, the exponential relationship curves between drape coefficient and rotating speed are obtained from the drape tester to describe the dynamic drapeability Finally, the stability of tested results of image-analysis-based system is studied.
基金National Natural Science Foundation of China (50275139) Natural Science Foundation of Zhejiang (01388-G)
文摘This paper introduces a new method of measuring the three-dimensional drape shape of fabrics with structural light. First, we apply parallel annular structural light to form light and shade alternating contour stripes on the surface of fabrics. We then collect the images of contour stripes using Charge Coupled Device (CCD). Subsequently, we process the images to identify the contour stripes and edges of fabrics, and obtain the fabric contour lines of curved surfaces. Finally, we apply three-dimensional curved surface modeling method based on a network of polar coordinates, and reconstruct the three-dimensional drape shape of fabrics. Experiments show that our method is effective in testing and reconstructing three-dimensional drape shape of fabrics.
