Due to the randomness of earthquake wave magnitude and direction, and the uncertain direction of strong axis and weak axis in the construction of engineering structures, the effect of the direction of ground motion on...Due to the randomness of earthquake wave magnitude and direction, and the uncertain direction of strong axis and weak axis in the construction of engineering structures, the effect of the direction of ground motion on a structure are studied herein. Ground motion records usually contain three vertical ground motion data, which are obtained by sensors arranged in accordance with the EW （East -West） direction, NS （South- North） direction and perpendicular to the surface （z） direction, referring to the construction standard of seismic stations. The seismic records in the EW and NS directions are converted to Cartesian coordinates in accordance with the rotation of θ = 0°-180°, and consequently, a countless group of new ground motion time histories are obtained. Then, the characteristics of the ground motion time history and response spectrum of each group were studied, resulting in the following observations： （1） the peak and phase of ground motion are changed with the rotation of direction θ, so that the direction θ of the maximum peak ground motion can be determined; （2） response spectrum values of each group of ground motions change along with the direction θ, and their peak, predominant period and declining curve are also different as the changes occur; then, the angle θ in the direction of the maximum peak value or the widest predominant period can be determined; and （3） the seismic response of structures with different directions of ground motion inputs has been analyzed under the same earthquake record, and the results show the difference. For some ground motion records, such as the Taft seismic wave, these differences are significant. Next, the Lushan middle school gymnasium structure was analyzed and the calculation was checked using the proposed method, where the internal force of the upper space truss varied from 25% to 28%. The research results presented herein can be used for reference in choosing the ground motion when checking the actual damage to structures following earthquakes and explaining the seismic damage. Meanwhile, it also provides a reference value for research into the most severe ground motion.展开更多
In the present research, hierarchical structure observation and mechanical property characterization for a type of biomaterial are carried out. The investigated bioma- terial is Hyriopsis cumingii, a typical limnetic ...In the present research, hierarchical structure observation and mechanical property characterization for a type of biomaterial are carried out. The investigated bioma- terial is Hyriopsis cumingii, a typical limnetic shell, which consists of two different structural layers, a prismatic ＂pillar＂ structure and a nacreous ＂brick and mortar＂ structure. The prismatic layer looks like a ＂pillar forest＂ with variationsection pillars sized on the order of several tens of microns. The nacreous material looks like a ＂brick wall＂ with bricks sized on the order of several microns. Both pillars and bricks are composed of nanoparticles. The mechanical properties of the hierarchical biomaterial are measured by using the nanoindentation test. Hardness and modulus are measured for both the nacre layer and the prismatic layer, respectively. The nanoindentation size effects for the hierarchical structural materials are investigated experimentally. The results show that the prismatic nanostructured material has a higher stiffness and hardness than the nacre nanostructured material. In addition, the nanoindentation size effects for the hierarchical structural materials are described theoretically, by using the trans-scale mechanics theory considering both strain gradient effect and the surface/interface effect. The modeling results are consistent with experimental ones.展开更多
In this study dynamic analysis of Soil Structure Interaction (SSI) effect on multi story reinforced concrete (RC) frame founded on soft soil (flexible base) is made and compared with fixed base. Two model 2D RC frames...In this study dynamic analysis of Soil Structure Interaction (SSI) effect on multi story reinforced concrete (RC) frame founded on soft soil (flexible base) is made and compared with fixed base. Two model 2D RC frames with 7 and 12 story are selected for analysis. Winkler Spring and half space direct method models are used for flexible base for the frames founded on two types of soft soils with shear velocity Vs < 150 m/s Asper Seismic Codes of Chinese GB50011-2010 Soil IV and Ethiopian ES8-2015 soil D. The frames are subjected to strong ground motion matched to response spectrums of soft soil of Chinese GB50011-2010 and Ethiopian ES8-2015 for linear time history analysis. The dynamic analysis result shows Spring and Fixed base mass participation 90% reaches in 2 or 3 modes but in direct method 11 to 30 modes for story 12 and 7 respectively. However, both flexible base models have bigger fundamental period of vibration and inter story drift but smaller base shear than fixed base. In addition, within the flexible base models the inter-story drift, second order effect (P-Δ) and Story shear distribution are different along the height of frames. The spring model shows larger Story drift and second order effect (P-Δ) at the bottom of Story for both soft soils types. On the other hand, half space direct method model indicates value reverse to spring model;it gives bigger Story drift and P-Δ effect in the top stories than fixed base. Finally, this study concludes that base shear reduction due to SSI may not be always beneficial. Because the gravity load is constant in both fixed and flexible bases that cause bigger P-Δ effect at the bottom stories due to increase, inter story drift and decrease story shear in flexible base.展开更多
Optimization of composition and microstructure is important to enhance performance of solid oxide fuel cells （SOFC） and lithium-ion batteries （LIB）. For this, the porous electrode structures of both SOFC and LIB a...Optimization of composition and microstructure is important to enhance performance of solid oxide fuel cells （SOFC） and lithium-ion batteries （LIB）. For this, the porous electrode structures of both SOFC and LIB are modeled as a binary mixture of electronic and ionic conducting particles to estimate effective transport properties. Particle packings of 10000 spherical, binary sized and randomly positioned particles are created numerically and densified considering the different manufacturing processes in SOFC and LIB： the sintering of SOFC electrodes is approximated geometrically, whereas the calendering process and volume change due to intercalation in LIB are modeled physically by a discrete el- ement approach. A combination of a tracking algorithm and a resistor network approach is developed to predict the con- nectivity and effective conductivity for the various densified structures. For SOFC, a systematic study of the influence of morphology on connectivity and conductivity is performed on a large number of assemblies with different compositions and particle size ratios between 1 and 10. In comparison to percolation theory, an enlarged percolation area is found, es- pecially for large size ratios. It is shown that in contrast to former studies the percolation threshold correlates to varying coordination numbers. The effective conductivity shows not only an increase with volume fraction as expected but also with size ratio. For LIB, a general increase of conductivity during the intercalation process was observed in correlation with increasing contact forces. The positive influence of cal- endering on the percolation threshold and the effective conductivity of carbon black is shown. The anisotropy caused by the calendering process does not influence the carbon black phase.展开更多
Using n-propylamine as a template,deioned water and secondary-butanol(butan-2-ol)as solvents,a three-dimensional(3D)open-framework aluminophosphate[C3NH10]·[HAl3P3O13](1)and a two-dimensional layered aluminophosp...Using n-propylamine as a template,deioned water and secondary-butanol(butan-2-ol)as solvents,a three-dimensional(3D)open-framework aluminophosphate[C3NH10]·[HAl3P3O13](1)and a two-dimensional layered aluminophosphate[C3NH10]3·[Al3P4O16](2)were crystallized from the initial mixtures with compositions of Al2O3:2.4 P2O5:5.0 n-propylamine:100 H2O/butan-2-ol,respectively.They are characterized by X-ray powder diffraction(XRD),thermogravimetric(TG),and elemental(CHN)analyses and structurally determined by single-crystal X-ray diffraction analysis.Compound 1 crystallizes in the monoclinic space group P21/c with a=0.85831(13)nm,b=1.7677(3)nm,c=1.04353(12)nm,=123.887(9)°,and V=1.3143(3)nm3.Compound 2 crystallizes in the monoclinic space group P21/c with a=1.1313(2)nm,b=1.4874(3)nm,c=1.8020(6)nm,=125.07(2)°,and V=2.4817(11)nm3.The results show that the properties of solvent have a significant influence on the structure-directing effect of n-propylamine in the crystallization of the open-framework aluminophosphates.展开更多
The crystallization behavior of the initial mixture with the composition of Al2O3：4.0P2O5：3.0 diethylenetriamine（DETA）：xHF：153H2O was investigated at 180 ℃, where 0≤x≤3. If x≤1.8, three-dimensional openframe...The crystallization behavior of the initial mixture with the composition of Al2O3：4.0P2O5：3.0 diethylenetriamine（DETA）：xHF：153H2O was investigated at 180 ℃, where 0≤x≤3. If x≤1.8, three-dimensional openframework aluminophosphate AIPO-CJ31 was obtained. If 2 ≤x≤3, a chain-like aluminophosphate（1） was obtained. The crystallization process of both compounds was investigated by means of powder X-ray diffraction（XRD） and the concentrations of A1 and P in the liquid product during the crystallization process were analysed by means of induc- tively coupled plasma atomic emission spectroscopy（ICP-AES）. The evolution of the coordination state of A1, P and F during the crystallization was monitored with 27A1, 31p and 19F MAS NMR technique. The influence of the fluoride ions and the source of fluoride ions on the structure-directing effect of DETA was discussed. It was found that the fluoride ions changed the crystallization direction of the initial mixture, i.e., the structure-directing effect of DETA, via altering the distribution or micro-structure of the inorganic fragments.展开更多
Using the statistical model of parton and applying the rescaling model tochoose nuclear parameters by fitting the experimental data in low-X and medium-X re-gion,the influence of EMC(European Muon Collaboration)effect...Using the statistical model of parton and applying the rescaling model tochoose nuclear parameters by fitting the experimental data in low-X and medium-X re-gion,the influence of EMC(European Muon Collaboration)effect on large-P_T directphoton production is studied.The result shows that the influence of EMC effect issmall.展开更多
Gaseous detonation propagating in a toroidal chamber was numerically studied for hydrogen/oxygen/nitrogen mixtures. The numerical method used is based on the three-dimensional Euler equations with detailed finiterate ...Gaseous detonation propagating in a toroidal chamber was numerically studied for hydrogen/oxygen/nitrogen mixtures. The numerical method used is based on the three-dimensional Euler equations with detailed finiterate chemistry. The results show that the calculated streak picture is in qualitative agreement with the picture recorded by a high speed streak camera from published literature. The three-dimensional flow field induced by a continuously rotating detonation was visualized and distinctive features of the rotating detonations were clearly depicted. Owing to the unconfined character of detonation wavelet, a deficit of detonation parameters was observed. Due to the effects of wall geometries, the strength of the outside detonation front is stronger than that of the inside portion. The detonation thus propagates with a constant circular velocity. Numerical simulation also shows three-dimensional rotating detonation structures, which display specific feature of the detonation- shock combined wave. Discrete burning gas pockets are formed due to instability of the discontinuity. It is believed that the present study could give an insight into the interest- ing properties of the continuously rotating detonation, and is thus beneficial to the design of continuous detonation propulsion systems.展开更多
Existing research on the measurement of the valuation effect mainly follows the residual method proposed by Lane and Milesi-Ferretti(2001).This cannot be used to perform structural decomposition.We propose an aggregat...Existing research on the measurement of the valuation effect mainly follows the residual method proposed by Lane and Milesi-Ferretti(2001).This cannot be used to perform structural decomposition.We propose an aggregation approach rather than the residual method to measure structurally the investment flow and valuation effect of China's external assets.The results indicate that the valuation effect of China's external assets has been highly volatile and it was negative during the pandemic period.The structural decomposition shows that portfolio investment and direct investment made the main contributions to the valuation effect.The impact of exchange rates on the valuation effect has generally been higher than that of asset price in terms of direct investment and total external assets but the opposite has been true for portfolio investment.China's outward investments are currently more inclined to Asian countries and a few European countries but inflows to China still mainly come from developed countries.展开更多
Dynamic characteristics of large permanent magnet direct‐drive generators(PMDGs)considering electromagnetic–structural coupling effects are analyzed in this study.Using the conformal mapping method,the scalar magnet...Dynamic characteristics of large permanent magnet direct‐drive generators(PMDGs)considering electromagnetic–structural coupling effects are analyzed in this study.Using the conformal mapping method,the scalar magnetic potential of the air gap magnetic field considering the slot effect is calculated.On the basis of the discrete current element and magnetic equivalent circuit model,the local magnetic saturation effect of the stator and rotor is quantitatively simulated and the air gap magnetic field intensity distribution is obtained via numerical simulation.A series of uniformly distributed equivalent electromagnetic springs are introduced to develop an electromagnetic–structural coupling finite element PMDG model.The proposed air gap field analysis method is verified by the finite element analysis results.On the basis of the test platform for the Goldwind 1.5MW PMDG,both modal and dynamic response tests for the stator/rotor coupling system are conducted,and the results are compared with the natural frequencies,mode shapes,and vibration responses obtained using the numerical model.The effects of the air gap length and rotor speed on the natural frequencies of the coupling system are analyzed.The proposed model has the potential to accurately evaluate the PMDG vibration energy,avoiding resonance points,and maintaining stable operations of the unit.展开更多
基金National Technology Research and Development Program of the Ministry of Science and Technology of China under Grant No.2015BAK17B03National Natural Science Foundation of China(General Program)under Grant No.51278152+1 种基金National Science & Technology Pillar Program(2015BAK17B06)Program for Innovation Research Team in China Earthquake Administration
文摘Due to the randomness of earthquake wave magnitude and direction, and the uncertain direction of strong axis and weak axis in the construction of engineering structures, the effect of the direction of ground motion on a structure are studied herein. Ground motion records usually contain three vertical ground motion data, which are obtained by sensors arranged in accordance with the EW （East -West） direction, NS （South- North） direction and perpendicular to the surface （z） direction, referring to the construction standard of seismic stations. The seismic records in the EW and NS directions are converted to Cartesian coordinates in accordance with the rotation of θ = 0°-180°, and consequently, a countless group of new ground motion time histories are obtained. Then, the characteristics of the ground motion time history and response spectrum of each group were studied, resulting in the following observations： （1） the peak and phase of ground motion are changed with the rotation of direction θ, so that the direction θ of the maximum peak ground motion can be determined; （2） response spectrum values of each group of ground motions change along with the direction θ, and their peak, predominant period and declining curve are also different as the changes occur; then, the angle θ in the direction of the maximum peak value or the widest predominant period can be determined; and （3） the seismic response of structures with different directions of ground motion inputs has been analyzed under the same earthquake record, and the results show the difference. For some ground motion records, such as the Taft seismic wave, these differences are significant. Next, the Lushan middle school gymnasium structure was analyzed and the calculation was checked using the proposed method, where the internal force of the upper space truss varied from 25% to 28%. The research results presented herein can be used for reference in choosing the ground motion when checking the actual damage to structures following earthquakes and explaining the seismic damage. Meanwhile, it also provides a reference value for research into the most severe ground motion.
基金The research was supported by the National Basic Research Program of China (Grant 2012CB937500),the National Natural Science Foundation of China (Grants 91216108,11432014),and the CAS/SAFEA International Partnership Program for Creative Reserch Teams
文摘In the present research, hierarchical structure observation and mechanical property characterization for a type of biomaterial are carried out. The investigated bioma- terial is Hyriopsis cumingii, a typical limnetic shell, which consists of two different structural layers, a prismatic ＂pillar＂ structure and a nacreous ＂brick and mortar＂ structure. The prismatic layer looks like a ＂pillar forest＂ with variationsection pillars sized on the order of several tens of microns. The nacreous material looks like a ＂brick wall＂ with bricks sized on the order of several microns. Both pillars and bricks are composed of nanoparticles. The mechanical properties of the hierarchical biomaterial are measured by using the nanoindentation test. Hardness and modulus are measured for both the nacre layer and the prismatic layer, respectively. The nanoindentation size effects for the hierarchical structural materials are investigated experimentally. The results show that the prismatic nanostructured material has a higher stiffness and hardness than the nacre nanostructured material. In addition, the nanoindentation size effects for the hierarchical structural materials are described theoretically, by using the trans-scale mechanics theory considering both strain gradient effect and the surface/interface effect. The modeling results are consistent with experimental ones.
文摘In this study dynamic analysis of Soil Structure Interaction (SSI) effect on multi story reinforced concrete (RC) frame founded on soft soil (flexible base) is made and compared with fixed base. Two model 2D RC frames with 7 and 12 story are selected for analysis. Winkler Spring and half space direct method models are used for flexible base for the frames founded on two types of soft soils with shear velocity Vs < 150 m/s Asper Seismic Codes of Chinese GB50011-2010 Soil IV and Ethiopian ES8-2015 soil D. The frames are subjected to strong ground motion matched to response spectrums of soft soil of Chinese GB50011-2010 and Ethiopian ES8-2015 for linear time history analysis. The dynamic analysis result shows Spring and Fixed base mass participation 90% reaches in 2 or 3 modes but in direct method 11 to 30 modes for story 12 and 7 respectively. However, both flexible base models have bigger fundamental period of vibration and inter story drift but smaller base shear than fixed base. In addition, within the flexible base models the inter-story drift, second order effect (P-Δ) and Story shear distribution are different along the height of frames. The spring model shows larger Story drift and second order effect (P-Δ) at the bottom of Story for both soft soils types. On the other hand, half space direct method model indicates value reverse to spring model;it gives bigger Story drift and P-Δ effect in the top stories than fixed base. Finally, this study concludes that base shear reduction due to SSI may not be always beneficial. Because the gravity load is constant in both fixed and flexible bases that cause bigger P-Δ effect at the bottom stories due to increase, inter story drift and decrease story shear in flexible base.
基金supported by the Helmholtz Portfolio "elektrochemische Speicher",particularly the work related to lithium-ion batteriespartially supported as part of the HeteroFoam Center,an Energy Frontier Research Center funded by the U.S.Department of Energy,Office of Science, Basic Energy Sciences(DE-SC0001061)+1 种基金support from the Center for Scientific Computing at the CNSI and MRL:an NSF MRSEC(DMR-1121053) and NSF (CNS-0960316)Australian Research Council Grant DE130101639
文摘Optimization of composition and microstructure is important to enhance performance of solid oxide fuel cells （SOFC） and lithium-ion batteries （LIB）. For this, the porous electrode structures of both SOFC and LIB are modeled as a binary mixture of electronic and ionic conducting particles to estimate effective transport properties. Particle packings of 10000 spherical, binary sized and randomly positioned particles are created numerically and densified considering the different manufacturing processes in SOFC and LIB： the sintering of SOFC electrodes is approximated geometrically, whereas the calendering process and volume change due to intercalation in LIB are modeled physically by a discrete el- ement approach. A combination of a tracking algorithm and a resistor network approach is developed to predict the con- nectivity and effective conductivity for the various densified structures. For SOFC, a systematic study of the influence of morphology on connectivity and conductivity is performed on a large number of assemblies with different compositions and particle size ratios between 1 and 10. In comparison to percolation theory, an enlarged percolation area is found, es- pecially for large size ratios. It is shown that in contrast to former studies the percolation threshold correlates to varying coordination numbers. The effective conductivity shows not only an increase with volume fraction as expected but also with size ratio. For LIB, a general increase of conductivity during the intercalation process was observed in correlation with increasing contact forces. The positive influence of cal- endering on the percolation threshold and the effective conductivity of carbon black is shown. The anisotropy caused by the calendering process does not influence the carbon black phase.
基金supported by the National Natural Science Foundation of China(21171063)the Excellent Young Scientists Fund(21222103)+1 种基金the National Basic Research Program of China(2011CB808-703)the Specialized Research Fund for the Doctoral Program of Higher Education
文摘Using n-propylamine as a template,deioned water and secondary-butanol(butan-2-ol)as solvents,a three-dimensional(3D)open-framework aluminophosphate[C3NH10]·[HAl3P3O13](1)and a two-dimensional layered aluminophosphate[C3NH10]3·[Al3P4O16](2)were crystallized from the initial mixtures with compositions of Al2O3:2.4 P2O5:5.0 n-propylamine:100 H2O/butan-2-ol,respectively.They are characterized by X-ray powder diffraction(XRD),thermogravimetric(TG),and elemental(CHN)analyses and structurally determined by single-crystal X-ray diffraction analysis.Compound 1 crystallizes in the monoclinic space group P21/c with a=0.85831(13)nm,b=1.7677(3)nm,c=1.04353(12)nm,=123.887(9)°,and V=1.3143(3)nm3.Compound 2 crystallizes in the monoclinic space group P21/c with a=1.1313(2)nm,b=1.4874(3)nm,c=1.8020(6)nm,=125.07(2)°,and V=2.4817(11)nm3.The results show that the properties of solvent have a significant influence on the structure-directing effect of n-propylamine in the crystallization of the open-framework aluminophosphates.
基金Supported by the National Natural Science Foundation of China（Nos.21571075, 21320102001, 21621001）, the National Key Research and Development Program of China（No.2016YFB0701100） and the Programme of Introducing Talents of Discipline to Universities（the 111 Project）, China（No.B 17020）.
文摘The crystallization behavior of the initial mixture with the composition of Al2O3：4.0P2O5：3.0 diethylenetriamine（DETA）：xHF：153H2O was investigated at 180 ℃, where 0≤x≤3. If x≤1.8, three-dimensional openframework aluminophosphate AIPO-CJ31 was obtained. If 2 ≤x≤3, a chain-like aluminophosphate（1） was obtained. The crystallization process of both compounds was investigated by means of powder X-ray diffraction（XRD） and the concentrations of A1 and P in the liquid product during the crystallization process were analysed by means of induc- tively coupled plasma atomic emission spectroscopy（ICP-AES）. The evolution of the coordination state of A1, P and F during the crystallization was monitored with 27A1, 31p and 19F MAS NMR technique. The influence of the fluoride ions and the source of fluoride ions on the structure-directing effect of DETA was discussed. It was found that the fluoride ions changed the crystallization direction of the initial mixture, i.e., the structure-directing effect of DETA, via altering the distribution or micro-structure of the inorganic fragments.
基金The project supported in part by the Provincial Science Foundation of Fujian,China.
文摘Using the statistical model of parton and applying the rescaling model tochoose nuclear parameters by fitting the experimental data in low-X and medium-X re-gion,the influence of EMC(European Muon Collaboration)effect on large-P_T directphoton production is studied.The result shows that the influence of EMC effect issmall.
基金supported by the National Natural Science Foundation of China (10872096)the Open Fund of State Key Laboratory of Explosion Science and Technology, Beijing University of Science and Technology (KFJJ09-13)
文摘Gaseous detonation propagating in a toroidal chamber was numerically studied for hydrogen/oxygen/nitrogen mixtures. The numerical method used is based on the three-dimensional Euler equations with detailed finiterate chemistry. The results show that the calculated streak picture is in qualitative agreement with the picture recorded by a high speed streak camera from published literature. The three-dimensional flow field induced by a continuously rotating detonation was visualized and distinctive features of the rotating detonations were clearly depicted. Owing to the unconfined character of detonation wavelet, a deficit of detonation parameters was observed. Due to the effects of wall geometries, the strength of the outside detonation front is stronger than that of the inside portion. The detonation thus propagates with a constant circular velocity. Numerical simulation also shows three-dimensional rotating detonation structures, which display specific feature of the detonation- shock combined wave. Discrete burning gas pockets are formed due to instability of the discontinuity. It is believed that the present study could give an insight into the interest- ing properties of the continuously rotating detonation, and is thus beneficial to the design of continuous detonation propulsion systems.
基金The authors appreciate the insightful comments and suggestions of editors and two anonymous reviewers.Guowei Cai thanks the National Natural Science Foundation of China(No.72073147)the National Social Science Major Project(No.22&ZD058)the Ministry of Education Humanities and Social Sciences Planning Foundation Project of China(No.19YJA790001)for their financial support.
文摘Existing research on the measurement of the valuation effect mainly follows the residual method proposed by Lane and Milesi-Ferretti(2001).This cannot be used to perform structural decomposition.We propose an aggregation approach rather than the residual method to measure structurally the investment flow and valuation effect of China's external assets.The results indicate that the valuation effect of China's external assets has been highly volatile and it was negative during the pandemic period.The structural decomposition shows that portfolio investment and direct investment made the main contributions to the valuation effect.The impact of exchange rates on the valuation effect has generally been higher than that of asset price in terms of direct investment and total external assets but the opposite has been true for portfolio investment.China's outward investments are currently more inclined to Asian countries and a few European countries but inflows to China still mainly come from developed countries.
基金National Natural Science Foundation of China,Grant/Award Numbers:11872222,11902173State Key Laboratory of Tribology,Grant/Award Number:SKLT2021D11。
文摘Dynamic characteristics of large permanent magnet direct‐drive generators(PMDGs)considering electromagnetic–structural coupling effects are analyzed in this study.Using the conformal mapping method,the scalar magnetic potential of the air gap magnetic field considering the slot effect is calculated.On the basis of the discrete current element and magnetic equivalent circuit model,the local magnetic saturation effect of the stator and rotor is quantitatively simulated and the air gap magnetic field intensity distribution is obtained via numerical simulation.A series of uniformly distributed equivalent electromagnetic springs are introduced to develop an electromagnetic–structural coupling finite element PMDG model.The proposed air gap field analysis method is verified by the finite element analysis results.On the basis of the test platform for the Goldwind 1.5MW PMDG,both modal and dynamic response tests for the stator/rotor coupling system are conducted,and the results are compared with the natural frequencies,mode shapes,and vibration responses obtained using the numerical model.The effects of the air gap length and rotor speed on the natural frequencies of the coupling system are analyzed.The proposed model has the potential to accurately evaluate the PMDG vibration energy,avoiding resonance points,and maintaining stable operations of the unit.
