The method of two-dimensional viscous space-time conservation element and solution element (CE/SE) can be used to calculate the gas-liquid two-phase interior flow field in pulse detonation engine (PDE). In this paper,...The method of two-dimensional viscous space-time conservation element and solution element (CE/SE) can be used to calculate the gas-liquid two-phase interior flow field in pulse detonation engine (PDE). In this paper, the evolution of the detonation wave and the distribution of its physical parameters were analyzed. The numerical results show that the change of axial velocity of gas is the same as that of detonation pressure. The larger the liquid droplet radius is, the longer the time to get stable detonation wave is. The calculated results coincide with the experimented results better.展开更多
The characteristics of high-filled embankment rheological settlement were analyzed;mechanical calculation model of high-filled embankment rheological settlement during constructing and running period was also put forw...The characteristics of high-filled embankment rheological settlement were analyzed;mechanical calculation model of high-filled embankment rheological settlement during constructing and running period was also put forward.Combining the macroscopic and microscopic deformation properties of the engineering soil grain,its constitutive model was set up and its characters were fully revealed,at the same time,its practical calculation formula under the action of dead-weight load was derived,which is feasible by analysis and comparison.展开更多
The bearing beams and the supporting beams under low velocity impact may be in four different strain stages of deformation depending on the impact intensity and beam structure strength.Based on the different judging c...The bearing beams and the supporting beams under low velocity impact may be in four different strain stages of deformation depending on the impact intensity and beam structure strength.Based on the different judging conditions of deformation stages,the corresponding calculation models are proposed,the calculation formulae for the determination of the impact force and the beam's lateral displacement are obtained.Calculation shows that the beam's total deflection is small when the flexibility of the supporting component is high and the effect of diminishing deflection disappears almost when the stiffness of the supporting component is high.展开更多
The current popular methods for decision making and project optimisation in mine ventilation contain a number of deficiencies as they are solely based on either subjective knowledge or objective information.This paper...The current popular methods for decision making and project optimisation in mine ventilation contain a number of deficiencies as they are solely based on either subjective knowledge or objective information.This paper presents a new approach to rank the alternatives by G1-coefficient of variation method.The focus of this approach is the use of the combination weighing,which is able to compensate for the deficiencies in the method of evaluation index single weighing.In the case study,an appropriate evaluation index system was established to determine the evaluation value of each ventilation mode.Then the proposed approach was used to select the best development face ventilation mode.The result shows that the proposed approach is able to rank the alternative development face ventilation mode reasonably,the combination weighing method had the advantages of both subjective and objective weighing methods in that it took into consideration of both the experience and wisdom of experts,and the new changes in objective conditions.This approach provides a more reasonable and reliable procedure to analyse and evaluate different ventilation modes.展开更多
In the finite element method,the numerical simulation of three-dimensional crack propagation is relatively rare,and it is often realized by commercial programs.In addition to the geometric complexity,the determination...In the finite element method,the numerical simulation of three-dimensional crack propagation is relatively rare,and it is often realized by commercial programs.In addition to the geometric complexity,the determination of the cracking direction constitutes a great challenge.In most cases,the local stress state provides the fundamental criterion to judge the presence of cracks and the direction of crack propagation.However,in the case of three-dimensional analysis,the coordination relationship between grid elements due to occurrence of cracks becomes a difficult problem for this method.In this paper,based on the extended finite element method,the stress-related function field is introduced into the calculation domain,and then the boundary value problem of the function is solved.Subsequently,the envelope surface of all propagation directions can be obtained at one time.At last,the possible surface can be selected as the direction of crack development.Based on the aforementioned procedure,such method greatly reduces the programming complexity of tracking the crack propagation.As a suitable method for simulating tension-induced failure,it can simulate multiple cracks simultaneously.展开更多
A kind of international rapid field measurement methods of hydraulic conductivity and it's applications in Sanjiang Plain have been introduced in the paper.
A kind of international rapid field measurement methods of hydraulic conductivity and it's applications in Sanjiang Plain have been introduced in the paper.
The matters of equipment optimization development are usually discrete,fuzzy and non-quantitative.It is difficult directly to optimize the equipment development with a mathematical model.A set of methods for designing...The matters of equipment optimization development are usually discrete,fuzzy and non-quantitative.It is difficult directly to optimize the equipment development with a mathematical model.A set of methods for designing the equipment optimization development with six dimensions and eight main elements is established based on the theory and method of standardization.The top-tier design space of systematic development of equipment is built up by the relations of basic models,series and model spectrums.The relations of time and space for equipment optimization development are established.The design processes of a six dimension systematic space are expounded.The connotation of each plan in the main system space is analyzed.A design method for an entire equipment is established with standardization theory.The coordinating design methods of equipment technical system and the optimization design methods of equipment integration are discussed.The design methods for universalization and serialization of components and parts are established.The design methods of equipment optimization development highlight the relations of the basic model of platform,the serialization of platform basic models,the modularization of equipment functions,the model spectrum of variant equipment,and the universalization and serialization of components and parts.展开更多
Microsatellite marker (or Simple Sequence Repeate, SSR) is a marker technology based on DNA molecular length poly morphism. It is also one of the most commonly used molecular markers. Traditional SSR marker developm...Microsatellite marker (or Simple Sequence Repeate, SSR) is a marker technology based on DNA molecular length poly morphism. It is also one of the most commonly used molecular markers. Traditional SSR marker development methods are relatively time-consuming and mostly relying on the known genome sequence information while recently developed methods of SSR marker based on RAPD, ISSR-PCR SSR, the use of hybrid options, sequence tag SSR library access and screening EST-SSR have been widely used. This paper gave an overview of the methods mentioned above for the development of SSR markers.展开更多
沉香是我国传统名贵南药,广泛应用于医药、香水、香料、宗教等方面,现已形成了工业、文化产业和农业三大类产业,市场价值极高。本研究在中国知网、维普网和万方数据库中以“沉香结香”为主题词检索,导出1978—2022年发表的文章,利用Cite...沉香是我国传统名贵南药,广泛应用于医药、香水、香料、宗教等方面,现已形成了工业、文化产业和农业三大类产业,市场价值极高。本研究在中国知网、维普网和万方数据库中以“沉香结香”为主题词检索,导出1978—2022年发表的文章,利用CiteSpace软件进行可视化分析;在Web of Science以“agarwood production method”为检索词,可视化分析1978—2022年发表的外文文献。结果表明,国内沉香结香的研究一共分为3个阶段,1978—2007年为萌芽阶段,仅有零星文章产出;2008—2017年为快速发展阶段,大量文章产出并在2017年达到顶峰(41篇);2018—2022年为稳定阶段,持续产出文章并维持在年均20篇以上;有关沉香结香机理的研究发文量前10的期刊中,90%等级均在科技核心以上,排在前10的研究结构均处于沉香产业发达地区。国外沉香结香的研究起源于2008年,整体发文量趋势逐年增加;被引量前10的期刊均为SCI;研究量前10的国家均为GDP前列的国家。有关沉香自然结香和人工结香差异分析的研究成为当前研究热点,未来如何利用2种不同沉香结香方式的成分差异发展沉香资源,将会是新的研究趋势。本研究结果将为科研人员研究提供进一步参考方向,也为生产种植者提供沉香结香参考。展开更多
基金Sponsored by the National Natural Science Foundation of China (10672080)
文摘The method of two-dimensional viscous space-time conservation element and solution element (CE/SE) can be used to calculate the gas-liquid two-phase interior flow field in pulse detonation engine (PDE). In this paper, the evolution of the detonation wave and the distribution of its physical parameters were analyzed. The numerical results show that the change of axial velocity of gas is the same as that of detonation pressure. The larger the liquid droplet radius is, the longer the time to get stable detonation wave is. The calculated results coincide with the experimented results better.
基金Project(06C843) supported by the Scientific Research Fund of Hunan Provincial Education Department,China
文摘The characteristics of high-filled embankment rheological settlement were analyzed;mechanical calculation model of high-filled embankment rheological settlement during constructing and running period was also put forward.Combining the macroscopic and microscopic deformation properties of the engineering soil grain,its constitutive model was set up and its characters were fully revealed,at the same time,its practical calculation formula under the action of dead-weight load was derived,which is feasible by analysis and comparison.
基金the National Science Foundation of China(50578158)
文摘The bearing beams and the supporting beams under low velocity impact may be in four different strain stages of deformation depending on the impact intensity and beam structure strength.Based on the different judging conditions of deformation stages,the corresponding calculation models are proposed,the calculation formulae for the determination of the impact force and the beam's lateral displacement are obtained.Calculation shows that the beam's total deflection is small when the flexibility of the supporting component is high and the effect of diminishing deflection disappears almost when the stiffness of the supporting component is high.
基金Projects(51504286,51374242)supported by the National Natural Science Foundation of ChinaProject(2015M572270)supported by China Postdoctoral Science FoundationProject(2015RS4004)supported by the Science and Technology Plan of Hunan Province,China
文摘The current popular methods for decision making and project optimisation in mine ventilation contain a number of deficiencies as they are solely based on either subjective knowledge or objective information.This paper presents a new approach to rank the alternatives by G1-coefficient of variation method.The focus of this approach is the use of the combination weighing,which is able to compensate for the deficiencies in the method of evaluation index single weighing.In the case study,an appropriate evaluation index system was established to determine the evaluation value of each ventilation mode.Then the proposed approach was used to select the best development face ventilation mode.The result shows that the proposed approach is able to rank the alternative development face ventilation mode reasonably,the combination weighing method had the advantages of both subjective and objective weighing methods in that it took into consideration of both the experience and wisdom of experts,and the new changes in objective conditions.This approach provides a more reasonable and reliable procedure to analyse and evaluate different ventilation modes.
基金Project(2017YFC0404802)supported by the National Key R&D Program of ChinaProjects(U1965206,51979143)supported by the National Natural Science Foundation of China。
文摘In the finite element method,the numerical simulation of three-dimensional crack propagation is relatively rare,and it is often realized by commercial programs.In addition to the geometric complexity,the determination of the cracking direction constitutes a great challenge.In most cases,the local stress state provides the fundamental criterion to judge the presence of cracks and the direction of crack propagation.However,in the case of three-dimensional analysis,the coordination relationship between grid elements due to occurrence of cracks becomes a difficult problem for this method.In this paper,based on the extended finite element method,the stress-related function field is introduced into the calculation domain,and then the boundary value problem of the function is solved.Subsequently,the envelope surface of all propagation directions can be obtained at one time.At last,the possible surface can be selected as the direction of crack development.Based on the aforementioned procedure,such method greatly reduces the programming complexity of tracking the crack propagation.As a suitable method for simulating tension-induced failure,it can simulate multiple cracks simultaneously.
文摘A kind of international rapid field measurement methods of hydraulic conductivity and it's applications in Sanjiang Plain have been introduced in the paper.
文摘A kind of international rapid field measurement methods of hydraulic conductivity and it's applications in Sanjiang Plain have been introduced in the paper.
文摘The matters of equipment optimization development are usually discrete,fuzzy and non-quantitative.It is difficult directly to optimize the equipment development with a mathematical model.A set of methods for designing the equipment optimization development with six dimensions and eight main elements is established based on the theory and method of standardization.The top-tier design space of systematic development of equipment is built up by the relations of basic models,series and model spectrums.The relations of time and space for equipment optimization development are established.The design processes of a six dimension systematic space are expounded.The connotation of each plan in the main system space is analyzed.A design method for an entire equipment is established with standardization theory.The coordinating design methods of equipment technical system and the optimization design methods of equipment integration are discussed.The design methods for universalization and serialization of components and parts are established.The design methods of equipment optimization development highlight the relations of the basic model of platform,the serialization of platform basic models,the modularization of equipment functions,the model spectrum of variant equipment,and the universalization and serialization of components and parts.
文摘Microsatellite marker (or Simple Sequence Repeate, SSR) is a marker technology based on DNA molecular length poly morphism. It is also one of the most commonly used molecular markers. Traditional SSR marker development methods are relatively time-consuming and mostly relying on the known genome sequence information while recently developed methods of SSR marker based on RAPD, ISSR-PCR SSR, the use of hybrid options, sequence tag SSR library access and screening EST-SSR have been widely used. This paper gave an overview of the methods mentioned above for the development of SSR markers.
文摘沉香是我国传统名贵南药,广泛应用于医药、香水、香料、宗教等方面,现已形成了工业、文化产业和农业三大类产业,市场价值极高。本研究在中国知网、维普网和万方数据库中以“沉香结香”为主题词检索,导出1978—2022年发表的文章,利用CiteSpace软件进行可视化分析;在Web of Science以“agarwood production method”为检索词,可视化分析1978—2022年发表的外文文献。结果表明,国内沉香结香的研究一共分为3个阶段,1978—2007年为萌芽阶段,仅有零星文章产出;2008—2017年为快速发展阶段,大量文章产出并在2017年达到顶峰(41篇);2018—2022年为稳定阶段,持续产出文章并维持在年均20篇以上;有关沉香结香机理的研究发文量前10的期刊中,90%等级均在科技核心以上,排在前10的研究结构均处于沉香产业发达地区。国外沉香结香的研究起源于2008年,整体发文量趋势逐年增加;被引量前10的期刊均为SCI;研究量前10的国家均为GDP前列的国家。有关沉香自然结香和人工结香差异分析的研究成为当前研究热点,未来如何利用2种不同沉香结香方式的成分差异发展沉香资源,将会是新的研究趋势。本研究结果将为科研人员研究提供进一步参考方向,也为生产种植者提供沉香结香参考。