Through a modified inherent strain model based on the minimum residual stress and deformation,three building schemes with different building postures and support structures were evaluated by finite element analysis.Re...Through a modified inherent strain model based on the minimum residual stress and deformation,three building schemes with different building postures and support structures were evaluated by finite element analysis.Results demonstrate that according to the principle of reducing the overall height of the building and reducing the support structure with a large tilt angle from the building direction,the residual stress and deformation can be effectively reduced by proper design of building posture and support before laser powder bed melting.Moreover,without the data of thermophysical property variation of Ti-6Al-4V artificial knee implants with temperature,predicting the residual stress and deformation with acceptable accuracy and reduced time cost can be achieved by the inherent strain model.展开更多
Clay deposits typically exhibit significant degrees of heterogeneity and anisotropy in their strength and stiffness properties.Such non-monotonic responses can significantly impact the stability analysis and design of...Clay deposits typically exhibit significant degrees of heterogeneity and anisotropy in their strength and stiffness properties.Such non-monotonic responses can significantly impact the stability analysis and design of overlying shallow foundations.In this study,the undrained bearing capacity of shallow foundations resting on inhomogeneous and anisotropic clay layers subjected to oblique-eccentric combined loading is investigated through a comprehensive series of finite element limit analysis(FELA)based on the well-established lower-bound theorem and second-order cone programming(SOCP).The heterogeneity of normally consolidated(NC)clays is simulated by adopting a well-known general model of undrained shear strength increasing linearly with depth.In contrast,for overconsolidated(OC)clays,the variation of undrained shear strength with depth is considered to follow a bilinear trend.Furthermore,the inherent anisotropy is accounted for by adopting different values of undrained shear strength along different directions within the soil medium,employing an iterative-based algorithm.The results of numerical simulations are utilized to investigate the influences of natural soil heterogeneity and inherent anisotropy on the ultimate bearing capacity,failure envelope,and failure mechanism of shallow foundations subjected to the various combinations of vertical-horizontal(V-H)and vertical-moment(V-M)loads.展开更多
Large-scale and heavily jointed rocks have inherent planes of anisotropy and secondary structural planes,such as dominant joint sets and random fractures,which result in significant differences in their failure mechan...Large-scale and heavily jointed rocks have inherent planes of anisotropy and secondary structural planes,such as dominant joint sets and random fractures,which result in significant differences in their failure mechanism and deformation behavior compared to other rock types.To address this issue,inherent anisotropic rocks with large-scale and dense joints are considered to be composed of the rock matrix,inherent planes of anisotropy,and secondary structural planes.Then a new implicit continuum model called LayerDFN is developed based on the crack tensor and damage tensor theories to characterize the mechanical properties of inherent anisotropic rocks.Furthermore,the LayerDFN model is implemented in the FLAC3D software,and a series of numerical results for typical example problems is compared with those obtained from the 3DEC,the analytical solutions,similar classical models,laboratory uniaxial compression tests,and field rigid bearing plate tests.The results demonstrate that the LayerDFN model can effectively capture the anisotropic mechanical properties of inherent anisotropic rocks,and can quantitatively characterize the damaging effect of the secondary structural planes.Overall,the numerical method based on the LayerDFN model provides a comprehensive and reliable approach for describing and analyzing the behavior of inherent anisotropic rocks,which will provide valuable insights for engineering design and decision-making processes.展开更多
Welding is commonly employed to connect large-scale components in practical engineering.Predicting the resulting deforma-tion and residual stresses during the welding process is typically essential.The thermal-elastic...Welding is commonly employed to connect large-scale components in practical engineering.Predicting the resulting deforma-tion and residual stresses during the welding process is typically essential.The thermal-elastic-plastic method simulates the welding process by examining heat distribution and elastic-plastic stresses.Despite its high computational accuracy,this method is often time-consuming,rendering it less suitable for large component welding predictions.In contrast,the inherent strain method skips the welding process and fo-cuses on the inherent strain in the weld and joint areas post-welding.This method is fast and convenient,particularly suitable for the analysis of large and complex structures.The results show that the error rate is 4.6%when using the inherent strain method to calculate the welding deformation of the test plate.In the calculation of welded parts,the error rate is 5%,which is within the tolerance of the actual engineering.In this paper,the simulation accuracy of the deformation results of the inherent strain method is validated by simulating fusion vacuum ves-sel mockup,aiming to reduce the cost of welding analysis by using this method and to provide reference for practical welding applications.展开更多
This thesis takes the Skopostheorie as the guiding principle,analyzes and explains some important yet tend-to-be neglected standards,that is,the inherent characteristics unique to each product or service category.By m...This thesis takes the Skopostheorie as the guiding principle,analyzes and explains some important yet tend-to-be neglected standards,that is,the inherent characteristics unique to each product or service category.By means of analyzing cases,either successful or undesirable,it suggests the brand name translation had better imply their underlying features.Such principles may result in amazing translations.展开更多
We tested and modified the quasi-analytical algorithm （QAA） using 57 groups of field data collected in the spring of 2003 in the Yellow Sea and East China Sea. The QAA performs well in deriving total absorption coef...We tested and modified the quasi-analytical algorithm （QAA） using 57 groups of field data collected in the spring of 2003 in the Yellow Sea and East China Sea. The QAA performs well in deriving total absorption coefficients of typical coastal waters. The average percentage difference （APD） is in a range of 13.9%-38.5% for the total absorption coefficient （13.9% at 440 nm）, and differences in particle backscattering coefficient bbp（2） are less than 50% （in the case of the updated QAA）. To obtain improved results, we modified the QAA by adjusting the empirical relationships. The modified algorithm is then applied to the field data to test its performance. The APDs were 44.7%-46.6% for bbp（λ） and 9.9%-32.8% （9.9% at 555 nm） for the total absorption coefficient. This indicates that the modified QAA derives better results. We also used the modified model to derive phytoplankton pigment absorption （aph） and detritus and CDOM absorption （aug） coefficients. The APDs for aph and a dg at 440 nm are 37.1% and 19.8%. In this paper, we discuss error sources using the measured dataset. More independent field data can improve this algorithm and derive better results.展开更多
Welding deformations can be predicted by inherent strains that are assumed to be distributed in the welds and nearby area. This method is more convenient compared with the thermo elasto plastic finite element method b...Welding deformations can be predicted by inherent strains that are assumed to be distributed in the welds and nearby area. This method is more convenient compared with the thermo elasto plastic finite element method because only elastic analysis is necessary. The problem is how to know the inherent strains in advance during deformation analysis. The relations between inherent strains and welding parameters based on some experimental curves and a 3 D FEM model were introduced. According to this study, the longitudinal and transverse inherent strains that are the most important factors on welding deformations can be determined. The effectiveness of the proposed methods is demonstrated through the deformation analysis of a large welded cylinder with multipass welds as an example.展开更多
With a growing population, an increasing number of petrochemical facilities are built with larger capacity and more complexity, which pose a great risk to assets, community and environment. The value of inherently saf...With a growing population, an increasing number of petrochemical facilities are built with larger capacity and more complexity, which pose a great risk to assets, community and environment. The value of inherently safer design is recognized with time by all stakeholders, and an effective tool is needed to evaluate and compare inherent safety of alternative technologies. This study developed a safety index to evaluate existing technologies for their safety levels and guide inherently safer design. The Integrated Risk-based Safety Index(IRSI) was developed based on a comprehensive review of petrochemical processes, incident cases from Sinopec and US Chemical Safety Board, and existing safety index systems. The IRSI included all major hazards, including fire, explosion,toxic release, dust explosion, physical explosion, and runaway. Also, the integrated life cycle approach considered chemical hazards, equipment failure rates and safety measures in this risk-based index. Advanced modeling techniques, PHAST simulation and Neural Network, were used in the development of three novel sub-indices in the projects, fire, explosion and toxic release. The index system could be easily incorporated into a user friendly tool for the ease of application. A case study of hydrogen dioxide was conducted using the IRSI, which showed its capability for evaluating the safety level of process facilities.展开更多
A potential energy framework for assessment of grid vulnerability was presented.In the framework,the branch potential energy function model was constructed.Two indexes,current vulnerability and forecasting vulnerabili...A potential energy framework for assessment of grid vulnerability was presented.In the framework,the branch potential energy function model was constructed.Two indexes,current vulnerability and forecasting vulnerability,were calculated.The current vulnerability was used to identify the current vulnerable area through calculating the distance between the current transmitted power and initial transmitted power;and the forecast vulnerability under variation of power injection was used to predict the vulnerable area of next step and verify the current vulnerable area.Numerical simulation was performed under variant operating conditions with IEEE-30 bus system,which shows that almost area of 90% overlaps between current vulnerable area and forecasting vulnerable area,the overlapped area is termed as inherent vulnerable area of grid.When considering N-1 contingency,the assessment results of this method proposed agree with those of optimal power flow.When considering N-2 contingency,optimal power flow fails to obtain correct results,while the method based on energy framework gives reliable results.展开更多
Digraph-based causal models have been widely used to model the cause and effect behavior of process systems. Signed digraphs （SDG） capture the direction of the effect. It should be mentioned that there are loops in ...Digraph-based causal models have been widely used to model the cause and effect behavior of process systems. Signed digraphs （SDG） capture the direction of the effect. It should be mentioned that there are loops in SDG generated from chemical process. From the point of the inherent operability, the worst unsafe factor is the SDG having positive loops that means any disturbance occurring within the loop will propagate through the nodes one by one and are amplified gradually, so the system may lose control, which may lead to an accident. So finding the positive loops in a SDG and treating these unsafe factors in a proper manner can improve the inherent safety of a chemical process. This article proposed a method that can detect the above-mentioned unsafe factors in the proc- ess conceptual design stage automatically through the analysis of the SDG generated from the chemical process. A case study is illustrated to show the working of the algorithm, and then a complicated case from industry is studied to depict the effectiveness of the proposed algorithm.展开更多
Strengthening and toughening mechanisms in composite ceramics is complex. A change in a single parameter induces multiple property variations. The multiple changes in properties are often incompletely represented in t...Strengthening and toughening mechanisms in composite ceramics is complex. A change in a single parameter induces multiple property variations. The multiple changes in properties are often incompletely represented in theoretical models. This incompleteness in the parameter chosen fails to explain the mechanism of failure in composite ceramics. The exponential toughness function is used to represent the pull-out toughening mechanism, which dominates the crack growth resistance curve（R-curve）. The strengthening-toughening model is established based on the Mori-Tanaka method（M-T method）. The influence of inherent defects on toughness function and strength is analyzed by using this model. The theoretical result is compared with the experiment data. This model exactly reflects the change in strength. The theoretical result indicates that defects change the toughness function. Moreover, micro-cracks increase toughness size ac, and the strength of crack instable extensions acutely decreases as defect content increases. This presented model establishes the relationship among the important mechanical parameters of defect, strength, elastic modulus, and the R-curve.展开更多
Although the exact mechanism（s）of the degeneration of dopaminergic neurons in Parkinson’s disease（PD）is not well understood,mitochondrial dysfunction is proposed to play a central role.This proposal is strongly s...Although the exact mechanism（s）of the degeneration of dopaminergic neurons in Parkinson’s disease（PD）is not well understood,mitochondrial dysfunction is proposed to play a central role.This proposal is strongly strengthened by the findings that compromised mitochondrial functions and/or exposure to mitochondrial toxins such as rotenone,paraquat,or MPTP causes degeneration of the midbrain dopaminergic.展开更多
The contribution percentage of inherent soil productivity(CPISP)refers to the ratio of crop yields under no-fertilization versus under conventional fertilization with the same field management.CPISP is a comprehensive...The contribution percentage of inherent soil productivity(CPISP)refers to the ratio of crop yields under no-fertilization versus under conventional fertilization with the same field management.CPISP is a comprehensive measure of soil fertility.This study used 1086 on-farm trials(from 1984-2013)and 27 long-term field experiments(from 1979-2013)to quantify changes in CPISP.Here,we present CPISP3 values,which reflect the CPISP states during the first three years after site establishment,for a series of sites at different locations in China collected in 1984-1990(the 1980s),1996-2000(the 1990s),and 2004-2013(the 2000s).The results showed that the average CPISP3 value for three crops(wheat,rice,and maize)was 53.8%.Historically,the CPISP3 in the 1990s(57.5%)was much higher than those in the 1980s(50.3%),and the 2000s(52.0%)(P≤0.05).Long-term no-fertilization caused CPISP levels to gradually decline and then stabilize;for example,in a mono-cropping system with irrigation,the CPISP values in Northwest and Northeast China declined by 4.5 and 4.0%,respectively,each year for the first ten years,but subsequently,the CPISP values stabilized.In contrast,the CPISP for upland crops in double-cropping systems continued to decrease at a rate of 1.1%per year.The CPISP for upland-paddy cropping decreased very slowly(0.07%per year),whereas the CPISP for paddy cropping decreased sharply(3.1%per year,on average)for the first two years and then remained steady during the following years.Therefore,upland crops in double-cropping systems consume the most inherent soil productivity,whereas paddy fields are favourable for maintaining a high level of CPISP.Overall,our results demonstrate a need to further improve China’s CPISP3 values to meet growing productivity demands.展开更多
The molten salt reactor(MSR) has received much recent attention. The presence of beryllium and the mixing of actinides with light nuclei in the fuel salt result in a relatively strong neutron source that can affect th...The molten salt reactor(MSR) has received much recent attention. The presence of beryllium and the mixing of actinides with light nuclei in the fuel salt result in a relatively strong neutron source that can affect the surveillance at subcritical and transient characteristics during operation. In this study, we predict the inherent neutron sources based on a MSR model. The calculation shows that in the fresh core, the inherent neutron sources are mainly from alpha-induced neutrons. After power operation, the inherent neutron sources become remarkably stronger due to photoneutrons. Although being an insignificant part in the total neutron population during operation, the inherent neutron sources can be used as the installed neutron source after shutdown. If the MSR has continuously operated at full power(2 MWt) for 10 days,then there would be no need for the installed source within80 days after shutdown. After operating constantly for500 days, the installed neutron source can be eliminated within 2 years after shutdown.展开更多
According to the relationship between the meshing stiffness and the inherent characteristics of a seven-speed three-row coupled planetary transmission mechanism,a equivalent concentrated mass dynamics model of the pla...According to the relationship between the meshing stiffness and the inherent characteristics of a seven-speed three-row coupled planetary transmission mechanism,a equivalent concentrated mass dynamics model of the planetary transmission mechanism is established.The natural frequency of the planetary gear train at a specific gear is calculated and extracted.The relationship between the meshing stiffness of each row and the natural frequency of the system is analyzed,thereby avoiding possible resonance behavior by changing the meshing stiffness.These results show that the meshing stiffness,in its range of possible values,has nearly no effect on the low order natural frequency(<4.000.Hz),and that the time-varying meshing stiffness mainly affects the natural frequencies of the higher-and middle-order parts of the system.Changes of the natural frequencies lead to the change of the system's corresponding vibration mode,which will change the vibration situation of the system.展开更多
This paper introduces the composition of the premium rate of Inherent Defects Insurance,and analyzes the factors influencing the premium rate of the Inherent Defects Insurance.
A fundamental theory for the analysis of residual welding stresses and deformation based on the inherent strain distribution along the welded joint is introduced. The method of predicting maximum hardness Hv(y, z) and...A fundamental theory for the analysis of residual welding stresses and deformation based on the inherent strain distribution along the welded joint is introduced. The method of predicting maximum hardness Hv(y, z) and maximum inherent strain gmax is given. The model T.E.P-Tav-hardness calculation is proposed to predict distribution of inherent strains in T type welding structure. By T.E.P-Tav-hardness calculation, distribution of longitudinal inherent strains can be predicted in T type welding structure, and calculation and experimental results are consistent.展开更多
The NMR spectra revealed that the calixarene frame of 1, 3-disubstituted calix[4]arenes beating optically active groups is asymmetric, even without the formation of a sub-ring. This inherent chirality arises from the ...The NMR spectra revealed that the calixarene frame of 1, 3-disubstituted calix[4]arenes beating optically active groups is asymmetric, even without the formation of a sub-ring. This inherent chirality arises from the interaction of the two chiral groups, which hinder the substituents＇ free rotation. Thus, these chiral calix[4]arenes display good chiral recognition ability.展开更多
A model Cu-AlN composite has been prepared by ion implantation technique and annealing. The atomic configuration and lattice relationship of a low-energy inherent interface(11)Cn//(0001)AlN were studied by using trans...A model Cu-AlN composite has been prepared by ion implantation technique and annealing. The atomic configuration and lattice relationship of a low-energy inherent interface(11)Cn//(0001)AlN were studied by using transmission electron microscopy and geometrical modelling. By analysing the dichromatic pattern of the composite,a primary structural unit of the interface atomic configuration was determined for purpose of HREM image simulations and of studying the structurul relaxation state in the near-interface region.展开更多
基金Natural Science Foundation of Shandong Province(ZR2020ME020)。
文摘Through a modified inherent strain model based on the minimum residual stress and deformation,three building schemes with different building postures and support structures were evaluated by finite element analysis.Results demonstrate that according to the principle of reducing the overall height of the building and reducing the support structure with a large tilt angle from the building direction,the residual stress and deformation can be effectively reduced by proper design of building posture and support before laser powder bed melting.Moreover,without the data of thermophysical property variation of Ti-6Al-4V artificial knee implants with temperature,predicting the residual stress and deformation with acceptable accuracy and reduced time cost can be achieved by the inherent strain model.
文摘Clay deposits typically exhibit significant degrees of heterogeneity and anisotropy in their strength and stiffness properties.Such non-monotonic responses can significantly impact the stability analysis and design of overlying shallow foundations.In this study,the undrained bearing capacity of shallow foundations resting on inhomogeneous and anisotropic clay layers subjected to oblique-eccentric combined loading is investigated through a comprehensive series of finite element limit analysis(FELA)based on the well-established lower-bound theorem and second-order cone programming(SOCP).The heterogeneity of normally consolidated(NC)clays is simulated by adopting a well-known general model of undrained shear strength increasing linearly with depth.In contrast,for overconsolidated(OC)clays,the variation of undrained shear strength with depth is considered to follow a bilinear trend.Furthermore,the inherent anisotropy is accounted for by adopting different values of undrained shear strength along different directions within the soil medium,employing an iterative-based algorithm.The results of numerical simulations are utilized to investigate the influences of natural soil heterogeneity and inherent anisotropy on the ultimate bearing capacity,failure envelope,and failure mechanism of shallow foundations subjected to the various combinations of vertical-horizontal(V-H)and vertical-moment(V-M)loads.
基金supported by financial support from the National Natural Science Foundation of China(Grant Nos.52309122 and U2340229)the Innovation Team of Changjiang River Scientific Research Institute(Grant No.CKSF2024329/YT).
文摘Large-scale and heavily jointed rocks have inherent planes of anisotropy and secondary structural planes,such as dominant joint sets and random fractures,which result in significant differences in their failure mechanism and deformation behavior compared to other rock types.To address this issue,inherent anisotropic rocks with large-scale and dense joints are considered to be composed of the rock matrix,inherent planes of anisotropy,and secondary structural planes.Then a new implicit continuum model called LayerDFN is developed based on the crack tensor and damage tensor theories to characterize the mechanical properties of inherent anisotropic rocks.Furthermore,the LayerDFN model is implemented in the FLAC3D software,and a series of numerical results for typical example problems is compared with those obtained from the 3DEC,the analytical solutions,similar classical models,laboratory uniaxial compression tests,and field rigid bearing plate tests.The results demonstrate that the LayerDFN model can effectively capture the anisotropic mechanical properties of inherent anisotropic rocks,and can quantitatively characterize the damaging effect of the secondary structural planes.Overall,the numerical method based on the LayerDFN model provides a comprehensive and reliable approach for describing and analyzing the behavior of inherent anisotropic rocks,which will provide valuable insights for engineering design and decision-making processes.
基金supported by the National Key Scientific and Technological Infrastructure Construction Project(No.2018-000052-73-01-001228)National Natural Science Foundation of China Young Scientists Fund Project(12105185)Science Foundation of Institute of Plasma Physics,Chinese Academy of Sciences(No.DSJJ-2023-06).
文摘Welding is commonly employed to connect large-scale components in practical engineering.Predicting the resulting deforma-tion and residual stresses during the welding process is typically essential.The thermal-elastic-plastic method simulates the welding process by examining heat distribution and elastic-plastic stresses.Despite its high computational accuracy,this method is often time-consuming,rendering it less suitable for large component welding predictions.In contrast,the inherent strain method skips the welding process and fo-cuses on the inherent strain in the weld and joint areas post-welding.This method is fast and convenient,particularly suitable for the analysis of large and complex structures.The results show that the error rate is 4.6%when using the inherent strain method to calculate the welding deformation of the test plate.In the calculation of welded parts,the error rate is 5%,which is within the tolerance of the actual engineering.In this paper,the simulation accuracy of the deformation results of the inherent strain method is validated by simulating fusion vacuum ves-sel mockup,aiming to reduce the cost of welding analysis by using this method and to provide reference for practical welding applications.
文摘This thesis takes the Skopostheorie as the guiding principle,analyzes and explains some important yet tend-to-be neglected standards,that is,the inherent characteristics unique to each product or service category.By means of analyzing cases,either successful or undesirable,it suggests the brand name translation had better imply their underlying features.Such principles may result in amazing translations.
基金Supported by the National Natural Science Foundation of China (Nos.40706060,60802089)the National High Technology Research and Development Program of China (863 Program) (No.2007AA092102)the Dragon Project (No.5292)
文摘We tested and modified the quasi-analytical algorithm （QAA） using 57 groups of field data collected in the spring of 2003 in the Yellow Sea and East China Sea. The QAA performs well in deriving total absorption coefficients of typical coastal waters. The average percentage difference （APD） is in a range of 13.9%-38.5% for the total absorption coefficient （13.9% at 440 nm）, and differences in particle backscattering coefficient bbp（2） are less than 50% （in the case of the updated QAA）. To obtain improved results, we modified the QAA by adjusting the empirical relationships. The modified algorithm is then applied to the field data to test its performance. The APDs were 44.7%-46.6% for bbp（λ） and 9.9%-32.8% （9.9% at 555 nm） for the total absorption coefficient. This indicates that the modified QAA derives better results. We also used the modified model to derive phytoplankton pigment absorption （aph） and detritus and CDOM absorption （aug） coefficients. The APDs for aph and a dg at 440 nm are 37.1% and 19.8%. In this paper, we discuss error sources using the measured dataset. More independent field data can improve this algorithm and derive better results.
基金National Natural Science Foundation ofChina!( No. 592 752 0 3)
文摘Welding deformations can be predicted by inherent strains that are assumed to be distributed in the welds and nearby area. This method is more convenient compared with the thermo elasto plastic finite element method because only elastic analysis is necessary. The problem is how to know the inherent strains in advance during deformation analysis. The relations between inherent strains and welding parameters based on some experimental curves and a 3 D FEM model were introduced. According to this study, the longitudinal and transverse inherent strains that are the most important factors on welding deformations can be determined. The effectiveness of the proposed methods is demonstrated through the deformation analysis of a large welded cylinder with multipass welds as an example.
基金Supported by the National Key Research and Development Program of China(2016YFB0301701)National Natural Science Foundation of China(21606258).
文摘With a growing population, an increasing number of petrochemical facilities are built with larger capacity and more complexity, which pose a great risk to assets, community and environment. The value of inherently safer design is recognized with time by all stakeholders, and an effective tool is needed to evaluate and compare inherent safety of alternative technologies. This study developed a safety index to evaluate existing technologies for their safety levels and guide inherently safer design. The Integrated Risk-based Safety Index(IRSI) was developed based on a comprehensive review of petrochemical processes, incident cases from Sinopec and US Chemical Safety Board, and existing safety index systems. The IRSI included all major hazards, including fire, explosion,toxic release, dust explosion, physical explosion, and runaway. Also, the integrated life cycle approach considered chemical hazards, equipment failure rates and safety measures in this risk-based index. Advanced modeling techniques, PHAST simulation and Neural Network, were used in the development of three novel sub-indices in the projects, fire, explosion and toxic release. The index system could be easily incorporated into a user friendly tool for the ease of application. A case study of hydrogen dioxide was conducted using the IRSI, which showed its capability for evaluating the safety level of process facilities.
基金Project(51007006) supported by the National Natural Science Foundation of ChinaProject(20090185120023) supported by the Ph.D Programs Foundation for New Teacher of Ministry of Education of China
文摘A potential energy framework for assessment of grid vulnerability was presented.In the framework,the branch potential energy function model was constructed.Two indexes,current vulnerability and forecasting vulnerability,were calculated.The current vulnerability was used to identify the current vulnerable area through calculating the distance between the current transmitted power and initial transmitted power;and the forecast vulnerability under variation of power injection was used to predict the vulnerable area of next step and verify the current vulnerable area.Numerical simulation was performed under variant operating conditions with IEEE-30 bus system,which shows that almost area of 90% overlaps between current vulnerable area and forecasting vulnerable area,the overlapped area is termed as inherent vulnerable area of grid.When considering N-1 contingency,the assessment results of this method proposed agree with those of optimal power flow.When considering N-2 contingency,optimal power flow fails to obtain correct results,while the method based on energy framework gives reliable results.
文摘Digraph-based causal models have been widely used to model the cause and effect behavior of process systems. Signed digraphs （SDG） capture the direction of the effect. It should be mentioned that there are loops in SDG generated from chemical process. From the point of the inherent operability, the worst unsafe factor is the SDG having positive loops that means any disturbance occurring within the loop will propagate through the nodes one by one and are amplified gradually, so the system may lose control, which may lead to an accident. So finding the positive loops in a SDG and treating these unsafe factors in a proper manner can improve the inherent safety of a chemical process. This article proposed a method that can detect the above-mentioned unsafe factors in the proc- ess conceptual design stage automatically through the analysis of the SDG generated from the chemical process. A case study is illustrated to show the working of the algorithm, and then a complicated case from industry is studied to depict the effectiveness of the proposed algorithm.
基金Supported by National Natural Science Foundation of China(Grant No11272355)
文摘Strengthening and toughening mechanisms in composite ceramics is complex. A change in a single parameter induces multiple property variations. The multiple changes in properties are often incompletely represented in theoretical models. This incompleteness in the parameter chosen fails to explain the mechanism of failure in composite ceramics. The exponential toughness function is used to represent the pull-out toughening mechanism, which dominates the crack growth resistance curve（R-curve）. The strengthening-toughening model is established based on the Mori-Tanaka method（M-T method）. The influence of inherent defects on toughness function and strength is analyzed by using this model. The theoretical result is compared with the experiment data. This model exactly reflects the change in strength. The theoretical result indicates that defects change the toughness function. Moreover, micro-cracks increase toughness size ac, and the strength of crack instable extensions acutely decreases as defect content increases. This presented model establishes the relationship among the important mechanical parameters of defect, strength, elastic modulus, and the R-curve.
文摘Although the exact mechanism（s）of the degeneration of dopaminergic neurons in Parkinson’s disease（PD）is not well understood,mitochondrial dysfunction is proposed to play a central role.This proposal is strongly strengthened by the findings that compromised mitochondrial functions and/or exposure to mitochondrial toxins such as rotenone,paraquat,or MPTP causes degeneration of the midbrain dopaminergic.
基金financially supported by the Agro-scientific Research in the Public Interest of China (201503122)the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences (CAAS-XTCX2016008)
文摘The contribution percentage of inherent soil productivity(CPISP)refers to the ratio of crop yields under no-fertilization versus under conventional fertilization with the same field management.CPISP is a comprehensive measure of soil fertility.This study used 1086 on-farm trials(from 1984-2013)and 27 long-term field experiments(from 1979-2013)to quantify changes in CPISP.Here,we present CPISP3 values,which reflect the CPISP states during the first three years after site establishment,for a series of sites at different locations in China collected in 1984-1990(the 1980s),1996-2000(the 1990s),and 2004-2013(the 2000s).The results showed that the average CPISP3 value for three crops(wheat,rice,and maize)was 53.8%.Historically,the CPISP3 in the 1990s(57.5%)was much higher than those in the 1980s(50.3%),and the 2000s(52.0%)(P≤0.05).Long-term no-fertilization caused CPISP levels to gradually decline and then stabilize;for example,in a mono-cropping system with irrigation,the CPISP values in Northwest and Northeast China declined by 4.5 and 4.0%,respectively,each year for the first ten years,but subsequently,the CPISP values stabilized.In contrast,the CPISP for upland crops in double-cropping systems continued to decrease at a rate of 1.1%per year.The CPISP for upland-paddy cropping decreased very slowly(0.07%per year),whereas the CPISP for paddy cropping decreased sharply(3.1%per year,on average)for the first two years and then remained steady during the following years.Therefore,upland crops in double-cropping systems consume the most inherent soil productivity,whereas paddy fields are favourable for maintaining a high level of CPISP.Overall,our results demonstrate a need to further improve China’s CPISP3 values to meet growing productivity demands.
基金supported by the Chinese TMSR Strategic Pioneer Science and Technology Project under Grant No.XDA02010000
文摘The molten salt reactor(MSR) has received much recent attention. The presence of beryllium and the mixing of actinides with light nuclei in the fuel salt result in a relatively strong neutron source that can affect the surveillance at subcritical and transient characteristics during operation. In this study, we predict the inherent neutron sources based on a MSR model. The calculation shows that in the fresh core, the inherent neutron sources are mainly from alpha-induced neutrons. After power operation, the inherent neutron sources become remarkably stronger due to photoneutrons. Although being an insignificant part in the total neutron population during operation, the inherent neutron sources can be used as the installed neutron source after shutdown. If the MSR has continuously operated at full power(2 MWt) for 10 days,then there would be no need for the installed source within80 days after shutdown. After operating constantly for500 days, the installed neutron source can be eliminated within 2 years after shutdown.
基金National Natural Science Foundation of China(51375043)。
文摘According to the relationship between the meshing stiffness and the inherent characteristics of a seven-speed three-row coupled planetary transmission mechanism,a equivalent concentrated mass dynamics model of the planetary transmission mechanism is established.The natural frequency of the planetary gear train at a specific gear is calculated and extracted.The relationship between the meshing stiffness of each row and the natural frequency of the system is analyzed,thereby avoiding possible resonance behavior by changing the meshing stiffness.These results show that the meshing stiffness,in its range of possible values,has nearly no effect on the low order natural frequency(<4.000.Hz),and that the time-varying meshing stiffness mainly affects the natural frequencies of the higher-and middle-order parts of the system.Changes of the natural frequencies lead to the change of the system's corresponding vibration mode,which will change the vibration situation of the system.
文摘This paper introduces the composition of the premium rate of Inherent Defects Insurance,and analyzes the factors influencing the premium rate of the Inherent Defects Insurance.
文摘A fundamental theory for the analysis of residual welding stresses and deformation based on the inherent strain distribution along the welded joint is introduced. The method of predicting maximum hardness Hv(y, z) and maximum inherent strain gmax is given. The model T.E.P-Tav-hardness calculation is proposed to predict distribution of inherent strains in T type welding structure. By T.E.P-Tav-hardness calculation, distribution of longitudinal inherent strains can be predicted in T type welding structure, and calculation and experimental results are consistent.
基金support of the National Natural Science Foundation of China(No.20072007).
文摘The NMR spectra revealed that the calixarene frame of 1, 3-disubstituted calix[4]arenes beating optically active groups is asymmetric, even without the formation of a sub-ring. This inherent chirality arises from the interaction of the two chiral groups, which hinder the substituents＇ free rotation. Thus, these chiral calix[4]arenes display good chiral recognition ability.
文摘A model Cu-AlN composite has been prepared by ion implantation technique and annealing. The atomic configuration and lattice relationship of a low-energy inherent interface(11)Cn//(0001)AlN were studied by using transmission electron microscopy and geometrical modelling. By analysing the dichromatic pattern of the composite,a primary structural unit of the interface atomic configuration was determined for purpose of HREM image simulations and of studying the structurul relaxation state in the near-interface region.
