Sea-based rocket launches encounter significant challenges stemming from dynamic marine environmental interactions.During the hot launch phase,characterized by low-velocity ascent,the departure of the rocket from the ...Sea-based rocket launches encounter significant challenges stemming from dynamic marine environmental interactions.During the hot launch phase,characterized by low-velocity ascent,the departure of the rocket from the oscillatory platform exhibits heightened sensitivity to external disturbances.In the development stage,assessing the launch dynamics and the clearance between the rocket and framed launcher are crucial for improving the reliability of sea-based rocket launches in rough sea conditions.This study presents a high-fidelity dynamic model of maritime hot launch system,demonstrating 3.21%prediction error through rigorous validation against experimental datasets from comprehensive modal analyses and the full-scale rocket flight test.To mitigate collision risks,we develop a computational method employing spatial vector analysis for dynamic measurement of rocket-launcher clearance during departure.Systematic investigations reveal that in rough sea conditions,optimal departure dynamics are achieved at θ_(thrust)=270°nozzle azimuth configuration,reducing failure probability compared to conventional orientations.The developed assessment framework not only resolves critical safety challenges in current sea launch systems but also establishes foundational principles for optimizing adapter axial configuration patterns in future designs.展开更多
A new definition of the dual descriptor,namely,thethermodynamic dual descriptor,is developed within the grand canonicalpotential formalism.This new definition is formulated to describe the same △f_r(r)=β/2C[f^+(r)-f...A new definition of the dual descriptor,namely,thethermodynamic dual descriptor,is developed within the grand canonicalpotential formalism.This new definition is formulated to describe the same △f_r(r)=β/2C[f^+(r)-f^-(r)](C>0) physical phenomenon as the original definition proposed by Morell,Grand,and Toro-Labbé(J.Phys.Chem.A2005,109,205),which is characterized by a second-order response of the electron density towards an electron flux.To formulate the new definition,we performed two successive partial derivatives of the average electron density,one with respect to the average number of electrons,and the other with respect to the chemical potential of the electron reservoir.When the derivative is expressed in terms of the three-state ensemble model,in the regime of low temperatures up to temperatures of chemical interest,one finds that the thermodynamic dual descriptor can be expressed as?f_T(r)=(β/2)C[f^+(r)-f^-(r)],whereβ=1/k_BT,Cis a global quantity that depends on the temperature and global electronic properties of the molecule(the first ionization potential and the electron affinity),C=1 for systems with zero fractional charge,and C=C_ω>0(albeit very close to zero)for systems with nonzero fractional charge,,and f^+(r)and f^-(r)are the nucleophilic and electrophilic Fukui functions,respectively.The quantity within the square brackets is the original definition of the dual descriptor.As the local terms(the ones containing regioselectivity information)are equal to those of the dual descriptor,?f_T(r)has the same regioselectivity information,multiplied by the global quantity(β/2)C.This implies that the regioselectivity information contained in the original dual descriptor is preserved at all temperatures different from zero,and for any value of C>0.One of the most important features of this new definition is that it avoidsthe undesired Dirac delta behavior observed when the second order partial derivative of the average density is taken with respect to the average number of electrons,using the exact density dependence of the average number of electrons.展开更多
This paper investigates the sliding-mode-based fixed-time distributed average tracking (DAT) problem for multiple Euler-Lagrange systems in the presence of external distur-bances. The primary objective is to devise co...This paper investigates the sliding-mode-based fixed-time distributed average tracking (DAT) problem for multiple Euler-Lagrange systems in the presence of external distur-bances. The primary objective is to devise controllers for each agent, enabling them to precisely track the average of multiple time-varying reference signals. By averaging these signals, we can mitigate the influence of errors and uncertainties arising dur-ing measurements, thereby enhancing the robustness and stabi-lity of the system. A distributed fixed-time average estimator is proposed to estimate the average value of global reference sig-nals utilizing local information and communication with neigh-bors. Subsequently, a fixed-time sliding mode controller is intro-duced incorporating a state-dependent sliding mode function coupled with a variable exponent coefficient to achieve dis-tributed average tracking of reference signals, and rigorous ana-lytical methods are employed to substantiate the fixed-time sta-bility. Finally, numerical simulation results are provided to vali-date the effectiveness of the proposed methodology, offering insights into its practical application and robust performance.展开更多
为解决犹豫模糊集(hesitant fuzzy set,HFS)隶属度数值个数不一致的问题,讨论了现有数值延拓(numerical extending,NE)方法的局限性,提出基于Normative算子的HFS NE方法,在没有新息加入的条件下,依次选取现有HFS隶属度可能值的均值作为...为解决犹豫模糊集(hesitant fuzzy set,HFS)隶属度数值个数不一致的问题,讨论了现有数值延拓(numerical extending,NE)方法的局限性,提出基于Normative算子的HFS NE方法,在没有新息加入的条件下,依次选取现有HFS隶属度可能值的均值作为一个新的延拓隶属度,直至所有HFS隶属度个数相等为止,并基于有序加权平均(ordered weighted averaging,OWA)算子归纳隶属度统一方法。最后将所提出的方法应用到多传感器电子侦察情报的多属性决策问题中,基于改进的逼近理想解(technique for order preferences by similarity to ideal solution,TOPSIS-ε)法对各信源HFS属性判决进行多属性决策。仿真试验分析了距离、距离参数、属性权重对决策结果的影响,并详细对比和验证了新方法在HFS隶属度NE方面的稳定性和直观性。展开更多
目的分析2012—2023年重庆市老年人自杀死亡率与死亡疾病负担变化趋势,为开展有针对性的干预提供建议。方法利用重庆市2012—2023年死因监测数据中根本死因为自杀(《国际疾病与相关健康问题统计分类第10版》编码:X60~X84、Y87)的60岁及...目的分析2012—2023年重庆市老年人自杀死亡率与死亡疾病负担变化趋势,为开展有针对性的干预提供建议。方法利用重庆市2012—2023年死因监测数据中根本死因为自杀(《国际疾病与相关健康问题统计分类第10版》编码:X60~X84、Y87)的60岁及以上老年人死亡个案,分析死亡率、标化死亡率、早死寿命损失年(years of life lost,YLL)率、平均寿命损失年(average years of life lost,AYLL)及不同死因构成比,比较不同性别和地区死亡率,率的趋势变化采用年度变化百分比(annual percent of change,APC)和平均年度变化百分比(average annual percent of change,AAPC)进行分析。结果2012—2023年60岁及以上老年人自杀死亡率与标化死亡率总体呈下降的趋势,分别以年均3.54%与4.02%下降,变化趋势均有统计学意义(P<0.05)。2012—2016年自杀死亡率以年均4.53%上升,2016—2021年以年均8.91%下降,变化趋势均有统计学意义(P<0.05)。仅2020年与2022年男性自杀死亡率高于女性(P<0.05)。2012—2023年男性自杀死亡率与标化死亡率分别以年均2.86%和3.44%下降,女性分别以年均4.21%和4.69%下降,变化趋势均有统计学意义(P<0.05)。农村地区老年人历年自杀死亡率均高于城市地区,差异均有统计学意义(P<0.05)。2012—2023年城市地区老年人自杀死亡率与标化死亡率均保持相对平稳的水平(P>0.05),而农村地区老年人自杀死亡率与标化死亡率分别以年均3.44%与4.02%下降(P<0.05)。60岁及以上老年人自杀导致的YLL率与AYLL分别由2012年的3.03‰与18.54年下降至2023年的2.26‰与17.50年,AAPC分别为-4.02%与-0.60%,变化趋势均有统计学意义(P<0.05)。比较历年不同自杀方式构成发现,杀虫剂中毒死亡占比呈下降的趋势,而悬吊死亡、从高处跳下、淹溺占比均呈上升的趋势(P<0.05)。结论重庆市60岁及以上老年人自杀死亡率较高,疾病负担较重,总体呈下降的趋势,应重视老年人自杀的早期识别与干预。展开更多
基金the experimental technology support provided by the China Academy of Launch Vehicle Technology
文摘Sea-based rocket launches encounter significant challenges stemming from dynamic marine environmental interactions.During the hot launch phase,characterized by low-velocity ascent,the departure of the rocket from the oscillatory platform exhibits heightened sensitivity to external disturbances.In the development stage,assessing the launch dynamics and the clearance between the rocket and framed launcher are crucial for improving the reliability of sea-based rocket launches in rough sea conditions.This study presents a high-fidelity dynamic model of maritime hot launch system,demonstrating 3.21%prediction error through rigorous validation against experimental datasets from comprehensive modal analyses and the full-scale rocket flight test.To mitigate collision risks,we develop a computational method employing spatial vector analysis for dynamic measurement of rocket-launcher clearance during departure.Systematic investigations reveal that in rough sea conditions,optimal departure dynamics are achieved at θ_(thrust)=270°nozzle azimuth configuration,reducing failure probability compared to conventional orientations.The developed assessment framework not only resolves critical safety challenges in current sea launch systems but also establishes foundational principles for optimizing adapter axial configuration patterns in future designs.
基金PWA thanks NSERC for support from the Canada Research Chairs, Compute Canada, and an NSERC Discovery Grant. MFP thanks Universidad Autonoma Metropolitana-Iztapalapa for a Visiting Professor Invitation. JLG and AV thank Conacyt for Grants 237045 and 128369
文摘A new definition of the dual descriptor,namely,thethermodynamic dual descriptor,is developed within the grand canonicalpotential formalism.This new definition is formulated to describe the same △f_r(r)=β/2C[f^+(r)-f^-(r)](C>0) physical phenomenon as the original definition proposed by Morell,Grand,and Toro-Labbé(J.Phys.Chem.A2005,109,205),which is characterized by a second-order response of the electron density towards an electron flux.To formulate the new definition,we performed two successive partial derivatives of the average electron density,one with respect to the average number of electrons,and the other with respect to the chemical potential of the electron reservoir.When the derivative is expressed in terms of the three-state ensemble model,in the regime of low temperatures up to temperatures of chemical interest,one finds that the thermodynamic dual descriptor can be expressed as?f_T(r)=(β/2)C[f^+(r)-f^-(r)],whereβ=1/k_BT,Cis a global quantity that depends on the temperature and global electronic properties of the molecule(the first ionization potential and the electron affinity),C=1 for systems with zero fractional charge,and C=C_ω>0(albeit very close to zero)for systems with nonzero fractional charge,,and f^+(r)and f^-(r)are the nucleophilic and electrophilic Fukui functions,respectively.The quantity within the square brackets is the original definition of the dual descriptor.As the local terms(the ones containing regioselectivity information)are equal to those of the dual descriptor,?f_T(r)has the same regioselectivity information,multiplied by the global quantity(β/2)C.This implies that the regioselectivity information contained in the original dual descriptor is preserved at all temperatures different from zero,and for any value of C>0.One of the most important features of this new definition is that it avoidsthe undesired Dirac delta behavior observed when the second order partial derivative of the average density is taken with respect to the average number of electrons,using the exact density dependence of the average number of electrons.
基金supported by the National Natural Science Foundation of China(61673130).
文摘This paper investigates the sliding-mode-based fixed-time distributed average tracking (DAT) problem for multiple Euler-Lagrange systems in the presence of external distur-bances. The primary objective is to devise controllers for each agent, enabling them to precisely track the average of multiple time-varying reference signals. By averaging these signals, we can mitigate the influence of errors and uncertainties arising dur-ing measurements, thereby enhancing the robustness and stabi-lity of the system. A distributed fixed-time average estimator is proposed to estimate the average value of global reference sig-nals utilizing local information and communication with neigh-bors. Subsequently, a fixed-time sliding mode controller is intro-duced incorporating a state-dependent sliding mode function coupled with a variable exponent coefficient to achieve dis-tributed average tracking of reference signals, and rigorous ana-lytical methods are employed to substantiate the fixed-time sta-bility. Finally, numerical simulation results are provided to vali-date the effectiveness of the proposed methodology, offering insights into its practical application and robust performance.
文摘为解决犹豫模糊集(hesitant fuzzy set,HFS)隶属度数值个数不一致的问题,讨论了现有数值延拓(numerical extending,NE)方法的局限性,提出基于Normative算子的HFS NE方法,在没有新息加入的条件下,依次选取现有HFS隶属度可能值的均值作为一个新的延拓隶属度,直至所有HFS隶属度个数相等为止,并基于有序加权平均(ordered weighted averaging,OWA)算子归纳隶属度统一方法。最后将所提出的方法应用到多传感器电子侦察情报的多属性决策问题中,基于改进的逼近理想解(technique for order preferences by similarity to ideal solution,TOPSIS-ε)法对各信源HFS属性判决进行多属性决策。仿真试验分析了距离、距离参数、属性权重对决策结果的影响,并详细对比和验证了新方法在HFS隶属度NE方面的稳定性和直观性。
文摘目的分析2012—2023年重庆市老年人自杀死亡率与死亡疾病负担变化趋势,为开展有针对性的干预提供建议。方法利用重庆市2012—2023年死因监测数据中根本死因为自杀(《国际疾病与相关健康问题统计分类第10版》编码:X60~X84、Y87)的60岁及以上老年人死亡个案,分析死亡率、标化死亡率、早死寿命损失年(years of life lost,YLL)率、平均寿命损失年(average years of life lost,AYLL)及不同死因构成比,比较不同性别和地区死亡率,率的趋势变化采用年度变化百分比(annual percent of change,APC)和平均年度变化百分比(average annual percent of change,AAPC)进行分析。结果2012—2023年60岁及以上老年人自杀死亡率与标化死亡率总体呈下降的趋势,分别以年均3.54%与4.02%下降,变化趋势均有统计学意义(P<0.05)。2012—2016年自杀死亡率以年均4.53%上升,2016—2021年以年均8.91%下降,变化趋势均有统计学意义(P<0.05)。仅2020年与2022年男性自杀死亡率高于女性(P<0.05)。2012—2023年男性自杀死亡率与标化死亡率分别以年均2.86%和3.44%下降,女性分别以年均4.21%和4.69%下降,变化趋势均有统计学意义(P<0.05)。农村地区老年人历年自杀死亡率均高于城市地区,差异均有统计学意义(P<0.05)。2012—2023年城市地区老年人自杀死亡率与标化死亡率均保持相对平稳的水平(P>0.05),而农村地区老年人自杀死亡率与标化死亡率分别以年均3.44%与4.02%下降(P<0.05)。60岁及以上老年人自杀导致的YLL率与AYLL分别由2012年的3.03‰与18.54年下降至2023年的2.26‰与17.50年,AAPC分别为-4.02%与-0.60%,变化趋势均有统计学意义(P<0.05)。比较历年不同自杀方式构成发现,杀虫剂中毒死亡占比呈下降的趋势,而悬吊死亡、从高处跳下、淹溺占比均呈上升的趋势(P<0.05)。结论重庆市60岁及以上老年人自杀死亡率较高,疾病负担较重,总体呈下降的趋势,应重视老年人自杀的早期识别与干预。
