[Objectives]This study was conducted to establish a quantitative assessment method for the textural quality of chieh-qua fruit.[Methods]Using two modes of a texture analyzer,namely TPA(texture profile analysis)and pun...[Objectives]This study was conducted to establish a quantitative assessment method for the textural quality of chieh-qua fruit.[Methods]Using two modes of a texture analyzer,namely TPA(texture profile analysis)and puncture,the index data of the fruit were obtained by setting different trigger forces,deformation levels,test speeds,as well as puncture speeds and puncture depths.The data included TPA hardness,adhesiveness,springiness,cohesiveness,gumminess,chewiness,resilience,as well as skin hardness,skin toughness,flesh hardness,fracturability,and compactness.[Results]Different deformation levels had a significant impact on all parameters.Hardness,adhesiveness,gumminess and chewiness showed a trend of first increasing and then decreasing with the deformation level increasing.When the deformation level was 30%,the adhesiveness,gumminess and chewiness reached their maximum values.When the deformation level was 50%,TPA hardness reached its maximum.When the compression speed was 3 mm/s,the measured values of TPA hardness,adhesiveness,chewiness,and resilience were at their maximums.The skin hardness varied significantly under different trigger forces.When the trigger force was 15 g,the skin hardness reached a maximum value of 944.63 g,and the skin toughness,flesh hardness,fracturability,and compactness also reach their maximum values respectively.When the puncture depth was 12 mm,the flesh hardness and skin toughness reached their maximums of 682.51 g and 1.82 mm,respectively.In the TPA mode,the flesh hardness of chieh-qua showed an extremely significant negative correlation with springiness,cohesiveness,and resilience(P<0.01).The fruit fracturability detected by puncture had an extremely significant positive correlation with compactness(P<0.01).[Conclusions]The evaluation method for measuring chieh-qua texture by combining TPA and the puncture mode could accurately and quantitatively reflect the differences in the flesh texture quality of chieh-qua.The optimal parameters for texture measurement of chieh-qua fruit were determined as a 15 g trigger force with 50%deformation and a 3 mm/s compression speed in TPA mode,and a 15 g trigger force with a 12 mm puncture depth in puncture mode.Puncture speed was found to have no significant effect on the texture indices of chieh-qua.展开更多
Cost-effectiveness analysis（CEA） is increasingly important in health care decision making.Cost-effectiveness threshold is a critical parameter in the cost-effectiveness analysis.This review introduces the concept of...Cost-effectiveness analysis（CEA） is increasingly important in health care decision making.Cost-effectiveness threshold is a critical parameter in the cost-effectiveness analysis.This review introduces the concept of cost-effectiveness threshold, summarizes its determining methods,and classifies the existing methods into two kinds according to budget constraints,then analyzes the merit and demerit of every methods.When there is a flexible budget,the methods for determining the cost-effectiveness threshold include inferring the threshold from previous decisions,comparison with other health care technology or transfer from elsewhere in the public sector,social willingness-to-pay approach,GDP per capita criteria,and rule of thumb.When there is a fixed budget,the methods for determining the cost-effectiveness threshold include shadow price approach,opportunity cost approach,and ICER threshold-searcher model.Each approach to determining threshold has its strength and weakness.The aim of this article is to introduce the existing methods and discuss the features of each method.The background information,such as the definition of threshold,is also described.The basic theory of cost-effectiveness threshold is elaborated,and we recommend the establishment of a cost-effectiveness threshold in the Chinese health care.展开更多
Identifying state transition and determining the critical value of the Duffing oscillator are crucial to indicating external signal existence and have a great influence on detection accuracy in weak signal detection. ...Identifying state transition and determining the critical value of the Duffing oscillator are crucial to indicating external signal existence and have a great influence on detection accuracy in weak signal detection. A circular zone counting （CZC） method is proposed in this paper, by combining the Duffing oscillator＇s phase trajectory feature and numerical calculation for quickly and accurately identifying state transition and determining the critical value, to realize a high- efficiency weak signal detection. Detailed model analysis and method construction of the CZC method are introduced. Numerical experiments into the reliability of the proposed CZC method compared with the maximum Lyapunov exponent （MLE） method are carried out. The CZC method is demonstrated to have better detecting ability than the MLE method, and furthermore it is simpler and clearer in calculation to extend to engineering application.展开更多
Evapotranspiration of a natural secondary white birch (Betula populifolia)forest in Maoershan Ecological Station was determined by water balance method, heat balance method and water and heat combination method. Resul...Evapotranspiration of a natural secondary white birch (Betula populifolia)forest in Maoershan Ecological Station was determined by water balance method, heat balance method and water and heat combination method. Results showed that the total evapotranspiration of the forest in the growing season was 3. 6mm/d. of which evapotrans piration from canopy xvas 2. 91 mm/d and that from forest floor was 0. 57 mm/d. and that in the non-growing season was 0. 8 mm/d.展开更多
Digital elevation models （DEMs） are widely used to define the flow direction in distributed hydrological models for simulation of streamflow. In recent decades, numerous methods for flow direction determination have...Digital elevation models （DEMs） are widely used to define the flow direction in distributed hydrological models for simulation of streamflow. In recent decades, numerous methods for flow direction determination have been applied successfully to mountainous regions. Nevertheless, some problems still exist when those methods are used for flat or gently sloped areas The present study reviews the conventional methods of determining flow direction for such landscapes and analyzes the problems of these methods. Two different methods of determining flow direction are discussed and were applied to the Xitiaoxi Catchment, located in the Taihu Basin in southern China, which has both mountainous and flat terrain. Both the agree method and the shortest path method use drainage networks derived from a remote sensing image to determine the correct location of the stream. The results indicate that the agree method provides a better fit with the DEM for the hilly region than the shortest path method. For the flat region where the flow has been diverted and rerouted by land managers, both methods require observation of the drainage network to determine the flow direction. In order to clarify the applicability of the two methods, both are employed in catchment hydrological models conceptually based on the Xinanjiang model and implemented with PCRaster. The simulation results show that both methods can be successfully applied in hydrological modeling. There are no evident differences in the modeled discharge when using the two methods at different spatial scales.展开更多
The effect from the interaction of the alternating current(AC)magnetic field with kilogram-level test mass(TM)limits the detectivity of the TianQin space-based gravitational wave detection.The quantifed effect require...The effect from the interaction of the alternating current(AC)magnetic field with kilogram-level test mass(TM)limits the detectivity of the TianQin space-based gravitational wave detection.The quantifed effect requires the determination of the AC magnetic susceptibilityχ(f)of the TM.A torque method is proposed to measure theχ(f)of kg-level samples at the mHz band with a precision of 1×10^(-7).Combined with our previous work[Phys.Rev.Appl.18044010(2022)],the general frequency-dependent susceptibility of the alloy cube with side length L and electrical conductivityσis determined asχ(f)=χ0+(0.24±0.01)σμ0L^(2)f from 0.1 mHz to 1 Hz.The determination is helpful for the preliminary estimation of the in-band eddy current efect in the TianQin noise budget.The technique can be adopted to accurately measureχ(f)of the actual TM in other precision experiments,where the magnetic noise is a signifcant detection limit.展开更多
A method to determine the design value of the extreme wave height is introduced in this paper. The method is, based on the theoretical distribution of wave heights or the experiential probability distribution of wave ...A method to determine the design value of the extreme wave height is introduced in this paper. The method is, based on the theoretical distribution of wave heights or the experiential probability distribution of wave heights, to calculate the mode of the extreme wave height and the design value with good assuredness. In fitting the experiential distribution of the observed wave heights, the paper adopts the simulating function of F(x) = 1 - exp[ ?axb exp( -cxd )] and the non-linear parameter in the function is determined by the Non-Linear Least Square Method. The practical application of the method has proved that it is not only simple and convenient, but also very effective in engineering design practice.展开更多
The time-dependent Jones Wilkins-Lee equation products for aluminized explosives. To obtain the of state （JWL-EOS） is applied to describe detonation state time-dependent JWL-EOS parameters, cylinder tests and underw...The time-dependent Jones Wilkins-Lee equation products for aluminized explosives. To obtain the of state （JWL-EOS） is applied to describe detonation state time-dependent JWL-EOS parameters, cylinder tests and underwater explosion experiments are performed. According to the result of the wall radial velocity in cylinder tests and the shock wave pressures in underwater explosion experiments, the time-dependent JWL-EOS parameters are determined by iterating these variables in AUTODYN hydroeode simulations until the experimental values are reproduced. In addition, to verify the reliability of the derived JWL-EOS parameters, the aluminized explosive experiment is conducted in concrete. The shock wave pressures in the affected concrete bodies are measured by using manganin pressure sensors, and the rod velocity is obtained by using a high-speed camera. Simultaneously, the shock wave pressure and the rod velocity are calculated by using the derived time-dependent JWL equation of state. The calculated results are in good agreement with the experimental data.展开更多
A single three point bend specimen compliance method for determining JIC of high strength high fracture toughness steels is presented and a formula for calculatinff J-integral is proposed as follows.It is simple and v...A single three point bend specimen compliance method for determining JIC of high strength high fracture toughness steels is presented and a formula for calculatinff J-integral is proposed as follows.It is simple and valid for high strength high fracture toughness steels. The values of JIC and KIC measured by this method are in good agreement with those measured by standard test method.展开更多
[ Objective] To study the effects of different pretreatment methods on determination of microelement in feed and thus find the best pre treatment method for each microetement, t Method] The samples （concentrated feed...[ Objective] To study the effects of different pretreatment methods on determination of microelement in feed and thus find the best pre treatment method for each microetement, t Method] The samples （concentrated feeding stuff and fodder） were pretreated through throe methods, that is, dry incineration method, HNOs HCIO, wetdecomposition method and microwave digestion method. Then the content of seven kinds of mi croelement （AI, Ca, Cu, Fe, Mn, Se and Zn） was determined by inductively coupled plasma atomic emission spectrometer （ICPAES）. I Result] These three methods were all suitable for the determination of Cu, Mn and Zn in concentrated feeding stuff and the determination of Cu and Ca in fodder. The content of Cu and Ca was higher in fodder detected by HNO3 HCIO, wetdecomposition method. The microwave digestion method was suitable for the determination of AI and Ca in concentrated feeding stuff and the determination of AI, Fe, Mn and Zn in fodder. The dry incinera tion method was fit for the determination of Fe in concentrated feeding stuff. [ Condusionl The content of different microelements should be deter mined after the feed is treated with different Ioretreatment methods.展开更多
According to the response relationship between landscape and water resource,the selection principle of important landscapes was determined from the perspectives of nature and history in this study,and determination me...According to the response relationship between landscape and water resource,the selection principle of important landscapes was determined from the perspectives of nature and history in this study,and determination methods or steps of important landscapes along the mainstream of Yellow River were also established to select important landscapes that should be protected.展开更多
Comprehensive English is a very basic and important course for English majors,according to the features of the text-book A New English Course,teachers should adopt the integration of grammar translation method and com...Comprehensive English is a very basic and important course for English majors,according to the features of the text-book A New English Course,teachers should adopt the integration of grammar translation method and communicative approach to improve students' linguistic competence and communicative competence.展开更多
Words acquisition should be the most decisive and basic part, though modern English education does not take enough attention, especially in college English teaching. A recent survey on the Internet reveals that colleg...Words acquisition should be the most decisive and basic part, though modern English education does not take enough attention, especially in college English teaching. A recent survey on the Internet reveals that college students are worrying about their words power very much, eager to find an efficient and effective way. Hence, various modes of word memorizing methods are collected and a brief classification and remark are available. By an overall analysis of those methods, a new approach compromised by different kinds of methods turns out. This new approach completely abides by the philosophy of pragmatism, and every idea with practical use will be introduced to it, e.g. psychology of language and so on.展开更多
This paper covers an experimental study on vocational students' participation in the class under task-based approach and traditional grammar-translation teaching method.As vocational colleges in China have develop...This paper covers an experimental study on vocational students' participation in the class under task-based approach and traditional grammar-translation teaching method.As vocational colleges in China have developed rapidly,teachers are still exploring and experimenting with different teaching approaches in order to find the suitable one(s).Using the theory of task-based approach,the grammartranslation method,the author conducts an experiment by recording.The following key issue has been addressed and some conclusive results have been made.The paper intends to find an answer to the following question:Under which teaching approach can students participate in the class more actively? Based on the above research work,the following result has been reached:Task-based approach can promote students' mastering of vocabulary and grammar,and students participate in the class more actively.The author would like to share her experiences with others in pedagogical studies of teaching vocational college students English.展开更多
With the world globalization, China's communication with other countries has become more frequent. It is in great demand that a large number of college graduates who not only master their major but also do well in...With the world globalization, China's communication with other countries has become more frequent. It is in great demand that a large number of college graduates who not only master their major but also do well in communication in English with English speakers. However, such graduates are scare because the backward teaching method-the Grammar-Traditional Method, cannot meet what the contemporary Chinese society demands. The reforms of the college English teaching are urgent and necessary. This paper first explores the major problems existing in the college English teaching. Furthermore, it introduces the basic theory of the Communicative Approach and analyzes its advantages in college English teaching.展开更多
Establishing the nutrient reference condition（baseline environmental condition） of lakes in an ecoregion is a critical consideration in the development of scientifically defensible aquatic nutrient criteria.Three me...Establishing the nutrient reference condition（baseline environmental condition） of lakes in an ecoregion is a critical consideration in the development of scientifically defensible aquatic nutrient criteria.Three methods were applied to determine reference conditions in the Eastern plain ecoregion lakes with respect to total phosphorus（TP）,total nitrogen（TN）,planktonic chlorophyll a（Chl-a） and Secchi depth（SD）.The reference condition value for the lakes in the Eastern plain ecoregion by the trisection method is TP of 0.029 mg/L,TN of 0.67 mg/L,Chl-a of 3.92 mg/m 3,SD of 0.85 m,and the reference condition range by the lake population distribution approach is TP of 0.014-0.043 mg/L,TN of 0.360-0.785 mg/L,Chl-a of 1.78-4.73 mg/m 3,SD of 0.68-1.21 m.Additionally,empirical models were developed for estimating the reference Chl-a concentration and SD successfully for lakes in the Eastern plain ecoregion.Overall,the data suggest that multiple methods can be used to determine reference conditions and that in Eastern plain ecoregion lakes the reference condition corresponds to a mesotrophic status.展开更多
Community resilience is becoming a growing concern for authorities and decision makers.This paper introduces two indicator-based methods to evaluate the resilience of communities based on the PEOPLES framework.PEOPLES...Community resilience is becoming a growing concern for authorities and decision makers.This paper introduces two indicator-based methods to evaluate the resilience of communities based on the PEOPLES framework.PEOPLES is a multi-layered framework that defines community resilience using seven dimensions.Each of the dimensions is described through a set of resilience indicators collected from literature and they are linked to a measure allowing the analytical computation of the indicator’s performance.The first method proposed in this paper requires data on previous disasters as an input and returns as output a performance function for each indicator and a performance function for the whole community.The second method exploits a knowledge-based fuzzy modeling for its implementation.This method allows a quantitative evaluation of the PEOPLES indicators using descriptive knowledge rather than deterministic data including the uncertainty involved in the analysis.The output of the fuzzy-based method is a resilience index for each indicator as well as a resilience index for the community.The paper also introduces an open source online tool in which the first method is implemented.A case study illustrating the application of the first method and the usage of the tool is also provided in the paper.展开更多
In one step inverse finite element approach, an initial blank shape is normally predicted from the final deformed shape. The final deformed shape needs to be trimmed into a final part after stamping, the trimmed area,...In one step inverse finite element approach, an initial blank shape is normally predicted from the final deformed shape. The final deformed shape needs to be trimmed into a final part after stamping, the trimmed area, therefore, needs to be compensated manually before using one step inverse approach, which causes low efficiency and in consistency with the real situation. To solve this problem, one step positive approach is proposed to simulate the sheet metal stamping process. Firstly the spatial initial solution of one step positive method is preliminarily obtained by using the mapping relationship and area coordinates, then based on the deformation theory the iterative solving is carried out in three-dimensional coordinate system by using quasi-conjugate-gradient method. During iterative process the contact judgment method is introduced to ensure that the nodes on the spatial initial solution are not separated from die surface. The predicted results of sheet metal forming process that include the shape and thickness of the stamped part can be obtained after the iterative solving process. The validity of the proposed approach is verified by comparing the predicted results obtained through the proposed approach with those obtained through the module of one step inverse approach in Autoform and the real stamped part. In one step positive method, the stamped shape of regular sheet can be calculated fast and effectively. During the iterative solution, the quasi-conjugate-gradient method is proposed to take the place of solving system of equations, and it can improve the stability and precision of the algorithm.展开更多
The hydroxyl radical(·OH)has a crucial function in the oxidation and removal of many atmospheric compounds that are harmful to health.Nevertheless,high reactivity,low atmospheric abundance,determination of hydrox...The hydroxyl radical(·OH)has a crucial function in the oxidation and removal of many atmospheric compounds that are harmful to health.Nevertheless,high reactivity,low atmospheric abundance,determination of hydroxyl,and hydroperoxyl radical’s quantity is very difficult.In the atmosphere and troposphere,hydroperoxyl radicals(HO_(2))are closely demanded in the chemical oxidation of the troposphere.But advances in technology have allowed researchers to improve the determination methods on the research of free radicals through some spectroscopic techniques.So far,several methods such as laser-induced fluorescence(LIF),high-performance liquid chromatography(HPLC),and chemical ionization mass spectroscopy have been identified and mostly used in determining the quantity of hydroxyl and hydroperoxyl radicals.In this systematic review,we have advised the use of scavenger as an advance for further researchers to circumvent some of these problems caused by free radicals.The primary goal of this review is to deepen our understanding of the functions of the most critical free radical(·OH,HO_(2))and also understand the currently used methods to quantify them in the atmosphere and troposphere.展开更多
Parasitic flows may occur in the numerical simulation of incompressible multiphase flow due to errors in the calculation of surface tension terms, specifically for the curvature and unit normal vector. An improved met...Parasitic flows may occur in the numerical simulation of incompressible multiphase flow due to errors in the calculation of surface tension terms, specifically for the curvature and unit normal vector. An improved method for calculating the surface tension based on the level set approach is proposed, in which the contribution of not only the center node but also the rest area of a control volume to the calculation of surface tension is considered in a balanced manner. The weighted integration method (WIM) is more consistent with the concept of a banded interface in the level set method. It is applied to the temporal evolution of a two-dimensional neutrally buoyant liquid drop and a buoyancy driven deformable bubble in an immiscible fluid for the validation of WIM. The results show that the parasitic flows are evidently suppressed by the weighted integration method. The weight factors for WIM in 3-D cases are also suggested.展开更多
基金Supported by Shanghai Agriculture Applied Technology Development Program (Grant No.T20220120).
文摘[Objectives]This study was conducted to establish a quantitative assessment method for the textural quality of chieh-qua fruit.[Methods]Using two modes of a texture analyzer,namely TPA(texture profile analysis)and puncture,the index data of the fruit were obtained by setting different trigger forces,deformation levels,test speeds,as well as puncture speeds and puncture depths.The data included TPA hardness,adhesiveness,springiness,cohesiveness,gumminess,chewiness,resilience,as well as skin hardness,skin toughness,flesh hardness,fracturability,and compactness.[Results]Different deformation levels had a significant impact on all parameters.Hardness,adhesiveness,gumminess and chewiness showed a trend of first increasing and then decreasing with the deformation level increasing.When the deformation level was 30%,the adhesiveness,gumminess and chewiness reached their maximum values.When the deformation level was 50%,TPA hardness reached its maximum.When the compression speed was 3 mm/s,the measured values of TPA hardness,adhesiveness,chewiness,and resilience were at their maximums.The skin hardness varied significantly under different trigger forces.When the trigger force was 15 g,the skin hardness reached a maximum value of 944.63 g,and the skin toughness,flesh hardness,fracturability,and compactness also reach their maximum values respectively.When the puncture depth was 12 mm,the flesh hardness and skin toughness reached their maximums of 682.51 g and 1.82 mm,respectively.In the TPA mode,the flesh hardness of chieh-qua showed an extremely significant negative correlation with springiness,cohesiveness,and resilience(P<0.01).The fruit fracturability detected by puncture had an extremely significant positive correlation with compactness(P<0.01).[Conclusions]The evaluation method for measuring chieh-qua texture by combining TPA and the puncture mode could accurately and quantitatively reflect the differences in the flesh texture quality of chieh-qua.The optimal parameters for texture measurement of chieh-qua fruit were determined as a 15 g trigger force with 50%deformation and a 3 mm/s compression speed in TPA mode,and a 15 g trigger force with a 12 mm puncture depth in puncture mode.Puncture speed was found to have no significant effect on the texture indices of chieh-qua.
文摘Cost-effectiveness analysis（CEA） is increasingly important in health care decision making.Cost-effectiveness threshold is a critical parameter in the cost-effectiveness analysis.This review introduces the concept of cost-effectiveness threshold, summarizes its determining methods,and classifies the existing methods into two kinds according to budget constraints,then analyzes the merit and demerit of every methods.When there is a flexible budget,the methods for determining the cost-effectiveness threshold include inferring the threshold from previous decisions,comparison with other health care technology or transfer from elsewhere in the public sector,social willingness-to-pay approach,GDP per capita criteria,and rule of thumb.When there is a fixed budget,the methods for determining the cost-effectiveness threshold include shadow price approach,opportunity cost approach,and ICER threshold-searcher model.Each approach to determining threshold has its strength and weakness.The aim of this article is to introduce the existing methods and discuss the features of each method.The background information,such as the definition of threshold,is also described.The basic theory of cost-effectiveness threshold is elaborated,and we recommend the establishment of a cost-effectiveness threshold in the Chinese health care.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61172047 and 61071025)
文摘Identifying state transition and determining the critical value of the Duffing oscillator are crucial to indicating external signal existence and have a great influence on detection accuracy in weak signal detection. A circular zone counting （CZC） method is proposed in this paper, by combining the Duffing oscillator＇s phase trajectory feature and numerical calculation for quickly and accurately identifying state transition and determining the critical value, to realize a high- efficiency weak signal detection. Detailed model analysis and method construction of the CZC method are introduced. Numerical experiments into the reliability of the proposed CZC method compared with the maximum Lyapunov exponent （MLE） method are carried out. The CZC method is demonstrated to have better detecting ability than the MLE method, and furthermore it is simpler and clearer in calculation to extend to engineering application.
文摘Evapotranspiration of a natural secondary white birch (Betula populifolia)forest in Maoershan Ecological Station was determined by water balance method, heat balance method and water and heat combination method. Results showed that the total evapotranspiration of the forest in the growing season was 3. 6mm/d. of which evapotrans piration from canopy xvas 2. 91 mm/d and that from forest floor was 0. 57 mm/d. and that in the non-growing season was 0. 8 mm/d.
基金supported by the Studies and Research in Sustainability Program (Deutscher Akademischer Austausch Dienst, DAAD)
文摘Digital elevation models （DEMs） are widely used to define the flow direction in distributed hydrological models for simulation of streamflow. In recent decades, numerous methods for flow direction determination have been applied successfully to mountainous regions. Nevertheless, some problems still exist when those methods are used for flat or gently sloped areas The present study reviews the conventional methods of determining flow direction for such landscapes and analyzes the problems of these methods. Two different methods of determining flow direction are discussed and were applied to the Xitiaoxi Catchment, located in the Taihu Basin in southern China, which has both mountainous and flat terrain. Both the agree method and the shortest path method use drainage networks derived from a remote sensing image to determine the correct location of the stream. The results indicate that the agree method provides a better fit with the DEM for the hilly region than the shortest path method. For the flat region where the flow has been diverted and rerouted by land managers, both methods require observation of the drainage network to determine the flow direction. In order to clarify the applicability of the two methods, both are employed in catchment hydrological models conceptually based on the Xinanjiang model and implemented with PCRaster. The simulation results show that both methods can be successfully applied in hydrological modeling. There are no evident differences in the modeled discharge when using the two methods at different spatial scales.
基金supported by the National Key R&D Program of China(Grant No.2020YFC2200500)the Key Laboratory of Tian Qin Project(Sun Yat-sen University),Ministry of Education+1 种基金the National Natural Science Foundation of China(Grant Nos.12075325,12005308,and 11605065)the Doctoral Research Foundation Project of Hubei University of Arts and Science(Grant No.kyqdf2059017)。
文摘The effect from the interaction of the alternating current(AC)magnetic field with kilogram-level test mass(TM)limits the detectivity of the TianQin space-based gravitational wave detection.The quantifed effect requires the determination of the AC magnetic susceptibilityχ(f)of the TM.A torque method is proposed to measure theχ(f)of kg-level samples at the mHz band with a precision of 1×10^(-7).Combined with our previous work[Phys.Rev.Appl.18044010(2022)],the general frequency-dependent susceptibility of the alloy cube with side length L and electrical conductivityσis determined asχ(f)=χ0+(0.24±0.01)σμ0L^(2)f from 0.1 mHz to 1 Hz.The determination is helpful for the preliminary estimation of the in-band eddy current efect in the TianQin noise budget.The technique can be adopted to accurately measureχ(f)of the actual TM in other precision experiments,where the magnetic noise is a signifcant detection limit.
文摘A method to determine the design value of the extreme wave height is introduced in this paper. The method is, based on the theoretical distribution of wave heights or the experiential probability distribution of wave heights, to calculate the mode of the extreme wave height and the design value with good assuredness. In fitting the experiential distribution of the observed wave heights, the paper adopts the simulating function of F(x) = 1 - exp[ ?axb exp( -cxd )] and the non-linear parameter in the function is determined by the Non-Linear Least Square Method. The practical application of the method has proved that it is not only simple and convenient, but also very effective in engineering design practice.
基金Supported by the National Natural Science Foundation of China under Grant No 11172042
文摘The time-dependent Jones Wilkins-Lee equation products for aluminized explosives. To obtain the of state （JWL-EOS） is applied to describe detonation state time-dependent JWL-EOS parameters, cylinder tests and underwater explosion experiments are performed. According to the result of the wall radial velocity in cylinder tests and the shock wave pressures in underwater explosion experiments, the time-dependent JWL-EOS parameters are determined by iterating these variables in AUTODYN hydroeode simulations until the experimental values are reproduced. In addition, to verify the reliability of the derived JWL-EOS parameters, the aluminized explosive experiment is conducted in concrete. The shock wave pressures in the affected concrete bodies are measured by using manganin pressure sensors, and the rod velocity is obtained by using a high-speed camera. Simultaneously, the shock wave pressure and the rod velocity are calculated by using the derived time-dependent JWL equation of state. The calculated results are in good agreement with the experimental data.
文摘A single three point bend specimen compliance method for determining JIC of high strength high fracture toughness steels is presented and a formula for calculatinff J-integral is proposed as follows.It is simple and valid for high strength high fracture toughness steels. The values of JIC and KIC measured by this method are in good agreement with those measured by standard test method.
文摘[ Objective] To study the effects of different pretreatment methods on determination of microelement in feed and thus find the best pre treatment method for each microetement, t Method] The samples （concentrated feeding stuff and fodder） were pretreated through throe methods, that is, dry incineration method, HNOs HCIO, wetdecomposition method and microwave digestion method. Then the content of seven kinds of mi croelement （AI, Ca, Cu, Fe, Mn, Se and Zn） was determined by inductively coupled plasma atomic emission spectrometer （ICPAES）. I Result] These three methods were all suitable for the determination of Cu, Mn and Zn in concentrated feeding stuff and the determination of Cu and Ca in fodder. The content of Cu and Ca was higher in fodder detected by HNO3 HCIO, wetdecomposition method. The microwave digestion method was suitable for the determination of AI and Ca in concentrated feeding stuff and the determination of AI, Fe, Mn and Zn in fodder. The dry incinera tion method was fit for the determination of Fe in concentrated feeding stuff. [ Condusionl The content of different microelements should be deter mined after the feed is treated with different Ioretreatment methods.
基金Supported by Modern Water Science Innovation Project of Ministry of Water Resources(XD2004-03-05)Key Project for National Science and Technology Supporting Plan during the Eleventh Five-Year Plan(2006BAB06B08-04)~~
文摘According to the response relationship between landscape and water resource,the selection principle of important landscapes was determined from the perspectives of nature and history in this study,and determination methods or steps of important landscapes along the mainstream of Yellow River were also established to select important landscapes that should be protected.
文摘Comprehensive English is a very basic and important course for English majors,according to the features of the text-book A New English Course,teachers should adopt the integration of grammar translation method and communicative approach to improve students' linguistic competence and communicative competence.
文摘Words acquisition should be the most decisive and basic part, though modern English education does not take enough attention, especially in college English teaching. A recent survey on the Internet reveals that college students are worrying about their words power very much, eager to find an efficient and effective way. Hence, various modes of word memorizing methods are collected and a brief classification and remark are available. By an overall analysis of those methods, a new approach compromised by different kinds of methods turns out. This new approach completely abides by the philosophy of pragmatism, and every idea with practical use will be introduced to it, e.g. psychology of language and so on.
文摘This paper covers an experimental study on vocational students' participation in the class under task-based approach and traditional grammar-translation teaching method.As vocational colleges in China have developed rapidly,teachers are still exploring and experimenting with different teaching approaches in order to find the suitable one(s).Using the theory of task-based approach,the grammartranslation method,the author conducts an experiment by recording.The following key issue has been addressed and some conclusive results have been made.The paper intends to find an answer to the following question:Under which teaching approach can students participate in the class more actively? Based on the above research work,the following result has been reached:Task-based approach can promote students' mastering of vocabulary and grammar,and students participate in the class more actively.The author would like to share her experiences with others in pedagogical studies of teaching vocational college students English.
文摘With the world globalization, China's communication with other countries has become more frequent. It is in great demand that a large number of college graduates who not only master their major but also do well in communication in English with English speakers. However, such graduates are scare because the backward teaching method-the Grammar-Traditional Method, cannot meet what the contemporary Chinese society demands. The reforms of the college English teaching are urgent and necessary. This paper first explores the major problems existing in the college English teaching. Furthermore, it introduces the basic theory of the Communicative Approach and analyzes its advantages in college English teaching.
基金supported by the Mega-projects of Science Research for Water Environment Improvement(No. 2009ZX07106-0012012ZX07101-002)+1 种基金he National Natural Science Foundation of China (No. 40901248)the National Basic Research Program (973) of China(No. 2008CB418206)
文摘Establishing the nutrient reference condition（baseline environmental condition） of lakes in an ecoregion is a critical consideration in the development of scientifically defensible aquatic nutrient criteria.Three methods were applied to determine reference conditions in the Eastern plain ecoregion lakes with respect to total phosphorus（TP）,total nitrogen（TN）,planktonic chlorophyll a（Chl-a） and Secchi depth（SD）.The reference condition value for the lakes in the Eastern plain ecoregion by the trisection method is TP of 0.029 mg/L,TN of 0.67 mg/L,Chl-a of 3.92 mg/m 3,SD of 0.85 m,and the reference condition range by the lake population distribution approach is TP of 0.014-0.043 mg/L,TN of 0.360-0.785 mg/L,Chl-a of 1.78-4.73 mg/m 3,SD of 0.68-1.21 m.Additionally,empirical models were developed for estimating the reference Chl-a concentration and SD successfully for lakes in the Eastern plain ecoregion.Overall,the data suggest that multiple methods can be used to determine reference conditions and that in Eastern plain ecoregion lakes the reference condition corresponds to a mesotrophic status.
基金European Research Council under Grant Agreement No.ERC_IDEAL RESCUE_637842 of the project IDEAL RESCUE-Integrated Design and Control of Sustainable Communities during Emergencies
文摘Community resilience is becoming a growing concern for authorities and decision makers.This paper introduces two indicator-based methods to evaluate the resilience of communities based on the PEOPLES framework.PEOPLES is a multi-layered framework that defines community resilience using seven dimensions.Each of the dimensions is described through a set of resilience indicators collected from literature and they are linked to a measure allowing the analytical computation of the indicator’s performance.The first method proposed in this paper requires data on previous disasters as an input and returns as output a performance function for each indicator and a performance function for the whole community.The second method exploits a knowledge-based fuzzy modeling for its implementation.This method allows a quantitative evaluation of the PEOPLES indicators using descriptive knowledge rather than deterministic data including the uncertainty involved in the analysis.The output of the fuzzy-based method is a resilience index for each indicator as well as a resilience index for the community.The paper also introduces an open source online tool in which the first method is implemented.A case study illustrating the application of the first method and the usage of the tool is also provided in the paper.
基金supported by National Natural Science Foundation of China (Grant No. 51075187)
文摘In one step inverse finite element approach, an initial blank shape is normally predicted from the final deformed shape. The final deformed shape needs to be trimmed into a final part after stamping, the trimmed area, therefore, needs to be compensated manually before using one step inverse approach, which causes low efficiency and in consistency with the real situation. To solve this problem, one step positive approach is proposed to simulate the sheet metal stamping process. Firstly the spatial initial solution of one step positive method is preliminarily obtained by using the mapping relationship and area coordinates, then based on the deformation theory the iterative solving is carried out in three-dimensional coordinate system by using quasi-conjugate-gradient method. During iterative process the contact judgment method is introduced to ensure that the nodes on the spatial initial solution are not separated from die surface. The predicted results of sheet metal forming process that include the shape and thickness of the stamped part can be obtained after the iterative solving process. The validity of the proposed approach is verified by comparing the predicted results obtained through the proposed approach with those obtained through the module of one step inverse approach in Autoform and the real stamped part. In one step positive method, the stamped shape of regular sheet can be calculated fast and effectively. During the iterative solution, the quasi-conjugate-gradient method is proposed to take the place of solving system of equations, and it can improve the stability and precision of the algorithm.
基金the National Key R&D Program of China(No.2016YFC0202900)the National Natural Science Foundation of China(Nos.21567015 and 21407072)+5 种基金the West Light Foundation of The Chinese Academy of Sciences(2019)special fund of State Key Joint Laboratory of Environment Simulation and Pollution Control(No.20K03ESPCP)the Natural Science Foundation of Gansu Province(Nos.18JR3RA079 and 17JR5RA109)the Project of Food and Drug Administration of Gansu Province(No.2018GSFDA014)the Gansu Provincial Party Committee Young Creative Talents(No.Ganzutongzi[2017]121)the Hongliu Science Fund for Distinguished Young Scholars(2018)。
文摘The hydroxyl radical(·OH)has a crucial function in the oxidation and removal of many atmospheric compounds that are harmful to health.Nevertheless,high reactivity,low atmospheric abundance,determination of hydroxyl,and hydroperoxyl radical’s quantity is very difficult.In the atmosphere and troposphere,hydroperoxyl radicals(HO_(2))are closely demanded in the chemical oxidation of the troposphere.But advances in technology have allowed researchers to improve the determination methods on the research of free radicals through some spectroscopic techniques.So far,several methods such as laser-induced fluorescence(LIF),high-performance liquid chromatography(HPLC),and chemical ionization mass spectroscopy have been identified and mostly used in determining the quantity of hydroxyl and hydroperoxyl radicals.In this systematic review,we have advised the use of scavenger as an advance for further researchers to circumvent some of these problems caused by free radicals.The primary goal of this review is to deepen our understanding of the functions of the most critical free radical(·OH,HO_(2))and also understand the currently used methods to quantify them in the atmosphere and troposphere.
基金Supported by the National Natural Science Foundation of China (No.20490206) and the Special Funds for Major State Basic Research Program of China (973 Program, 2004CB217604).
文摘Parasitic flows may occur in the numerical simulation of incompressible multiphase flow due to errors in the calculation of surface tension terms, specifically for the curvature and unit normal vector. An improved method for calculating the surface tension based on the level set approach is proposed, in which the contribution of not only the center node but also the rest area of a control volume to the calculation of surface tension is considered in a balanced manner. The weighted integration method (WIM) is more consistent with the concept of a banded interface in the level set method. It is applied to the temporal evolution of a two-dimensional neutrally buoyant liquid drop and a buoyancy driven deformable bubble in an immiscible fluid for the validation of WIM. The results show that the parasitic flows are evidently suppressed by the weighted integration method. The weight factors for WIM in 3-D cases are also suggested.
