1 Introduction Currently,all six different continents have discovered potash deposits and potash-bearing salt lake saline water.However,the distribution is extremely uneven,which is mostly concentrated in Canada,Russi...1 Introduction Currently,all six different continents have discovered potash deposits and potash-bearing salt lake saline water.However,the distribution is extremely uneven,which is mostly concentrated in Canada,Russia,Middle-Asia and展开更多
We statistically analyze the tropical typhoon forming in the South China Sea and use TC (Tropical Cyclone) for short in the following) by typhoon yearbook. The typhoon quantity is very different in different months an...We statistically analyze the tropical typhoon forming in the South China Sea and use TC (Tropical Cyclone) for short in the following) by typhoon yearbook. The typhoon quantity is very different in different months and years. TC appears in all months except March, and the most TC quantity in a year is 11, the least is 1 and 6.2 on average. The most TC quantity in a month is 5 and the least is 0. TC lands most in August and no TC lands on Chinese continent from December to the following April. The primary landing area is between Shantou and Hainan Island. The sustaining period of TC is usually between 4 days to 7days, and the longest is 19 days. Only 15% of the TC forming in the South China Sea can intensify to typhoon, and they all form in the ocean area deeper than 150m. The South China Sea is the ocean area over which the TC occurs frequently.展开更多
The forming limit diagram（FLD） is an important tool to be used when characterizing the formability of metallic sheets used in metal forming processes. Experimental measurement and determination of the FLD is timecon...The forming limit diagram（FLD） is an important tool to be used when characterizing the formability of metallic sheets used in metal forming processes. Experimental measurement and determination of the FLD is timeconsuming and therefore the analytical prediction based on theory of plasticity and instability criteria allows a direct and efficient methodology to obtain critical values at different loading paths, thus carrying significant practical importance.However, the accuracy of the plastic instability prediction is strongly dependent on the choice of the material constitutive model [1–3]. Particularly for materials with hexagonal close packed（HCP） crystallographic structure, they have a very limited number of active slip systems at room temperature and demonstrate a strong asymmetry between yielding in tension and compression [4, 5]. Not only the magnitude of the yield locus changes, but also the shape of the yield surface is evolving during the plastic deformation [4]. Conventional phenomenological constitutive models of plasticity fail to capture this unconventional mechanical behavior [4, 6]. Cazacu and Plunkett [6] have proposed generic yield criteria, by using the transformed principal stress, to account for the initial plastic anisotropy and strength differential（SD） effect simultaneously. In this contribution, a generic FLD MATLAB script was developed based on Marciniak–Kuczynski analytical theory and applied to predict the localized necking. The influence of asymmetrical effect on the FLD was evaluated. Several yield functions such as von Mises, Hill, Barlat89, and Cazacu06 were incorporated into analysis. The paper also presents and discusses the influence of different hardening laws on the formability of materials with HCP crystal structures. The findings indicate that the plastic instability theory coupled with Cazacu model can adequately predict the onset of localized necking for HCP materials under different strain paths.展开更多
Fiber metal laminates have many advantages over traditional laminates （e.g., any type of fiber and resin material can be placed anywhere between the metallic layers without risk of failure of the composite fabric she...Fiber metal laminates have many advantages over traditional laminates （e.g., any type of fiber and resin material can be placed anywhere between the metallic layers without risk of failure of the composite fabric sheets）. Furthermore, the process requirements to strictly control the temperature and punch force in fiber metal laminates are also less stringent than those in traditional laminates. To further explore the novel method, this study conducts a finite element method-based （FEM-based） strain analysis on multilayer blanks by using the 3A method. Different forming modes such as wrinkling and fracture are discussed by using experimental and numerical studies. Hydroforming is used for multilayer forming. The Barlat 2000 yield criteria and DYNAFORM/LS-DYNA are used for the simulations. Optimal process parameters are determined on the basis of fixed die-binder gap and variable cavity pressure. The results of this study will enhance the knowledge on the mechanics of multilayer structures formed by using the 3A method and expand its commercial applications.展开更多
Informal urban development is seldomly covered in academic studies or professional architectural training. This article sets forth the first stage of a novel study that observes the informal city using the methodology...Informal urban development is seldomly covered in academic studies or professional architectural training. This article sets forth the first stage of a novel study that observes the informal city using the methodology of analysis of architecture called shape grammars. The idea is to recognize peculiarities in the occupation of the land and the volumetric features of the buildings. Rocinha favela, in Rio de Janeiro, Brazil, is taken as a case study with the primary aim of extrapolating a set of rules for its morphological features so that these rules can be used to generate new shapes, whilst bearing in mind the issues of adaptation and transformation which are so characteristic of informal settlements. There is some expectation that this study may help improve the housing and public space in the favela and enable new housing programs to observe the way the buildings and different architectural elements combined, forming a new channel of interchange with the spatial organization of the favela.展开更多
Purpose: Assessment of contractile function is a major challenge in patients with left ventricular dysfunction, especially during cardiac surgery. The initial tangent of the femoral arterial pressure increase (tanin) ...Purpose: Assessment of contractile function is a major challenge in patients with left ventricular dysfunction, especially during cardiac surgery. The initial tangent of the femoral arterial pressure increase (tanin) has recently been described to be an estimate of left ventricular (LV) contractility. To confirm these findings tanin was compared to various indices of LV performance in patients undergoing cardiac surgery. Methods: Data from 17 patients were evaluated retrospectively. Myocardial performance was estimated by the echocardiographic indices ejection fraction (EF), shortening fraction (FS), circumferential fiber shortening velocity (Vcf), the parameters of pulse contour analysis area under the curve (AUC) and tanin. Measurements were taken before and after cardiopulmonary bypass (CPB). Results: Tanin increased significantly (813 ± 216 mmHg/s vs. 1490 ± 450 mmHg/s, p < 0.05) after CPB, as well as Vcf (0.89 ± 0.14 circ/s vs. 1.47 ± 0.27 circ/s, p < 0.05) and EF (65% ± 7% vs. 74% ± 6%, p < 0.05). FS did not change (40.7% ± 7% vs. 46.5% ± 5%, p = 0.30). AUC significantly dropped after CPB (435 ± 54 mmHg*s vs. 263 ± 27 mmHg*s). Tanin and Vcf correlated strongly (r = 0.70, p < 0.001), while tanin showed only weak correlation with EF (r = 0.36, p = 0.037). There was no significant correlation with FS (r = 0.31, p = 0.079). Tanin and AUC correlated inversely (r = -0.62, p < 0.001). Conclusions: While showing little or no correlation with EF and FS respectively, tanin correlated well with the less preload-dependent parameter Vcf, thus suggesting that tanin may be used as an easily accessible estimate of LV contractility during cardiac surgery.展开更多
When femtosecond laser pulses interfere with chirped femtosecond laser pulses in As2S3 fiber, a chirped fiber grating is formed. An analytical expression is given to describe the chirped grating, and its Bragg reflect...When femtosecond laser pulses interfere with chirped femtosecond laser pulses in As2S3 fiber, a chirped fiber grating is formed. An analytical expression is given to describe the chirped grating, and its Bragg reflectivity is calculated. Because of the high photosensitive effect of As2S3 material, the chirped fiber grating has a wide Bragg reflective spectrum and high reflectivity by choosing proper parameters. This indicates that the chirped fiber grating can be used as a stretcher in the femtosecond chirped pulse amplification (CPA) system.展开更多
Purpose:The purpose of this paper is to develop a novel interval Multi-Objective Optimization by a Ratio Analysis plus the Full Multiplicative Form(MULTIMOORA)with combination weights to evaluate the employment qualit...Purpose:The purpose of this paper is to develop a novel interval Multi-Objective Optimization by a Ratio Analysis plus the Full Multiplicative Form(MULTIMOORA)with combination weights to evaluate the employment quality of college graduates,where the criteria are expressed by interval numbers and the weights of criteria are completely unknown.Design/methodology/approach:Firstly,considering the subjective uncertainty of the weights of the criteria,the interval best worst method(I-BWM)was present to determine the subjective weights of the criteria.Secondly,bythe improvedinterval numberdistance measure,an improved interval deviationmaximizationmethod(I-MDM)was introduced to detemine the objective weights.In the following,based on the I-BWM and the improved I-MDM,a combination weighting method that takes into account the subjective and objective weights is proposed.Finally,a multi-criteria decision-making method based on the interval MULTIMOORA with combination weights is present toevaluate the employment quality of college graduates,and then a comparative analysis withsome of the existing distance measures of interval numberswas conducted to illustrate the flexibility.Findings:According to the data of the Report on Employment Quality of Chinese College Graduats released by MycosResearchInstitutein2016:2020and2021:2022,theproposedmethodwasusedtoevaluate theemployment quality of college graduates during the period before and after the COVID-19 epidemic.The results verify that the method is more reasonable because the subjective and objective weights of the criteria can be fully considered.Finally,the feasibility and practicability of the proposed method are further verified by varying parameters.Originality/value:Present an evaluation method on the employment quality of college graduates based on the Interval MULTIMOORA with combination weights considering the subjective and objective weights.And the proposed method is proved that it can provide a more reasonable evaluation results.At the same time,it is verified that the feasibility and the practicability of the proposed method are affected by varying parameters in the paper.展开更多
基金funded by National Program on Key Basic Research Project of China - 973 Program" Potash formation mechanism, conditions and late evolution in Ordovician ancient epicontinental sea basin, Erdos" (No. 2011CB403001)China Geological survey work Program - " Potash resources investigation and evaluation in Northern Shaanxi Ordovician Salt Basin " (No. 1212011085516)
文摘1 Introduction Currently,all six different continents have discovered potash deposits and potash-bearing salt lake saline water.However,the distribution is extremely uneven,which is mostly concentrated in Canada,Russia,Middle-Asia and
基金National Science Fund Project of Guangdong Province (04102749) Ocean Science andTechnology Director General Fund Project of the South China Sea Branch
文摘We statistically analyze the tropical typhoon forming in the South China Sea and use TC (Tropical Cyclone) for short in the following) by typhoon yearbook. The typhoon quantity is very different in different months and years. TC appears in all months except March, and the most TC quantity in a year is 11, the least is 1 and 6.2 on average. The most TC quantity in a month is 5 and the least is 0. TC lands most in August and no TC lands on Chinese continent from December to the following April. The primary landing area is between Shantou and Hainan Island. The sustaining period of TC is usually between 4 days to 7days, and the longest is 19 days. Only 15% of the TC forming in the South China Sea can intensify to typhoon, and they all form in the ocean area deeper than 150m. The South China Sea is the ocean area over which the TC occurs frequently.
基金support from the Portuguese Foundation for Science and Technology (FCT) via the projects PTDC/EMS-TEC/2404/2012, and PTDC/EMS-TEC/1805/2012FEDER funds through the program COMPETE-‘‘Programa Operacional Factores de Competitividade’’ is greatly acknowledged
文摘The forming limit diagram（FLD） is an important tool to be used when characterizing the formability of metallic sheets used in metal forming processes. Experimental measurement and determination of the FLD is timeconsuming and therefore the analytical prediction based on theory of plasticity and instability criteria allows a direct and efficient methodology to obtain critical values at different loading paths, thus carrying significant practical importance.However, the accuracy of the plastic instability prediction is strongly dependent on the choice of the material constitutive model [1–3]. Particularly for materials with hexagonal close packed（HCP） crystallographic structure, they have a very limited number of active slip systems at room temperature and demonstrate a strong asymmetry between yielding in tension and compression [4, 5]. Not only the magnitude of the yield locus changes, but also the shape of the yield surface is evolving during the plastic deformation [4]. Conventional phenomenological constitutive models of plasticity fail to capture this unconventional mechanical behavior [4, 6]. Cazacu and Plunkett [6] have proposed generic yield criteria, by using the transformed principal stress, to account for the initial plastic anisotropy and strength differential（SD） effect simultaneously. In this contribution, a generic FLD MATLAB script was developed based on Marciniak–Kuczynski analytical theory and applied to predict the localized necking. The influence of asymmetrical effect on the FLD was evaluated. Several yield functions such as von Mises, Hill, Barlat89, and Cazacu06 were incorporated into analysis. The paper also presents and discusses the influence of different hardening laws on the formability of materials with HCP crystal structures. The findings indicate that the plastic instability theory coupled with Cazacu model can adequately predict the onset of localized necking for HCP materials under different strain paths.
文摘Fiber metal laminates have many advantages over traditional laminates （e.g., any type of fiber and resin material can be placed anywhere between the metallic layers without risk of failure of the composite fabric sheets）. Furthermore, the process requirements to strictly control the temperature and punch force in fiber metal laminates are also less stringent than those in traditional laminates. To further explore the novel method, this study conducts a finite element method-based （FEM-based） strain analysis on multilayer blanks by using the 3A method. Different forming modes such as wrinkling and fracture are discussed by using experimental and numerical studies. Hydroforming is used for multilayer forming. The Barlat 2000 yield criteria and DYNAFORM/LS-DYNA are used for the simulations. Optimal process parameters are determined on the basis of fixed die-binder gap and variable cavity pressure. The results of this study will enhance the knowledge on the mechanics of multilayer structures formed by using the 3A method and expand its commercial applications.
文摘Informal urban development is seldomly covered in academic studies or professional architectural training. This article sets forth the first stage of a novel study that observes the informal city using the methodology of analysis of architecture called shape grammars. The idea is to recognize peculiarities in the occupation of the land and the volumetric features of the buildings. Rocinha favela, in Rio de Janeiro, Brazil, is taken as a case study with the primary aim of extrapolating a set of rules for its morphological features so that these rules can be used to generate new shapes, whilst bearing in mind the issues of adaptation and transformation which are so characteristic of informal settlements. There is some expectation that this study may help improve the housing and public space in the favela and enable new housing programs to observe the way the buildings and different architectural elements combined, forming a new channel of interchange with the spatial organization of the favela.
文摘Purpose: Assessment of contractile function is a major challenge in patients with left ventricular dysfunction, especially during cardiac surgery. The initial tangent of the femoral arterial pressure increase (tanin) has recently been described to be an estimate of left ventricular (LV) contractility. To confirm these findings tanin was compared to various indices of LV performance in patients undergoing cardiac surgery. Methods: Data from 17 patients were evaluated retrospectively. Myocardial performance was estimated by the echocardiographic indices ejection fraction (EF), shortening fraction (FS), circumferential fiber shortening velocity (Vcf), the parameters of pulse contour analysis area under the curve (AUC) and tanin. Measurements were taken before and after cardiopulmonary bypass (CPB). Results: Tanin increased significantly (813 ± 216 mmHg/s vs. 1490 ± 450 mmHg/s, p < 0.05) after CPB, as well as Vcf (0.89 ± 0.14 circ/s vs. 1.47 ± 0.27 circ/s, p < 0.05) and EF (65% ± 7% vs. 74% ± 6%, p < 0.05). FS did not change (40.7% ± 7% vs. 46.5% ± 5%, p = 0.30). AUC significantly dropped after CPB (435 ± 54 mmHg*s vs. 263 ± 27 mmHg*s). Tanin and Vcf correlated strongly (r = 0.70, p < 0.001), while tanin showed only weak correlation with EF (r = 0.36, p = 0.037). There was no significant correlation with FS (r = 0.31, p = 0.079). Tanin and AUC correlated inversely (r = -0.62, p < 0.001). Conclusions: While showing little or no correlation with EF and FS respectively, tanin correlated well with the less preload-dependent parameter Vcf, thus suggesting that tanin may be used as an easily accessible estimate of LV contractility during cardiac surgery.
基金The authors acknowledge the support of the National Key Basic Research Special Foundation of China (No. G1999075201-2)the National Natural Science Foundation of China (No. 60178007)the Science Foundation of China for Post Ph. D (2002032163).
文摘When femtosecond laser pulses interfere with chirped femtosecond laser pulses in As2S3 fiber, a chirped fiber grating is formed. An analytical expression is given to describe the chirped grating, and its Bragg reflectivity is calculated. Because of the high photosensitive effect of As2S3 material, the chirped fiber grating has a wide Bragg reflective spectrum and high reflectivity by choosing proper parameters. This indicates that the chirped fiber grating can be used as a stretcher in the femtosecond chirped pulse amplification (CPA) system.
基金supported in part by the National Natural Science Foundation of China(No.11371130)the Youth Innovation Fund of Xiamen City(3-502Z20206020).
文摘Purpose:The purpose of this paper is to develop a novel interval Multi-Objective Optimization by a Ratio Analysis plus the Full Multiplicative Form(MULTIMOORA)with combination weights to evaluate the employment quality of college graduates,where the criteria are expressed by interval numbers and the weights of criteria are completely unknown.Design/methodology/approach:Firstly,considering the subjective uncertainty of the weights of the criteria,the interval best worst method(I-BWM)was present to determine the subjective weights of the criteria.Secondly,bythe improvedinterval numberdistance measure,an improved interval deviationmaximizationmethod(I-MDM)was introduced to detemine the objective weights.In the following,based on the I-BWM and the improved I-MDM,a combination weighting method that takes into account the subjective and objective weights is proposed.Finally,a multi-criteria decision-making method based on the interval MULTIMOORA with combination weights is present toevaluate the employment quality of college graduates,and then a comparative analysis withsome of the existing distance measures of interval numberswas conducted to illustrate the flexibility.Findings:According to the data of the Report on Employment Quality of Chinese College Graduats released by MycosResearchInstitutein2016:2020and2021:2022,theproposedmethodwasusedtoevaluate theemployment quality of college graduates during the period before and after the COVID-19 epidemic.The results verify that the method is more reasonable because the subjective and objective weights of the criteria can be fully considered.Finally,the feasibility and practicability of the proposed method are further verified by varying parameters.Originality/value:Present an evaluation method on the employment quality of college graduates based on the Interval MULTIMOORA with combination weights considering the subjective and objective weights.And the proposed method is proved that it can provide a more reasonable evaluation results.At the same time,it is verified that the feasibility and the practicability of the proposed method are affected by varying parameters in the paper.
