The design of mini-missiles(MMs)presents several novel challenges.The stringent mission requirement to reach a target with a certain precision imposes a high guidance precision.The miniaturization of the size of MMs m...The design of mini-missiles(MMs)presents several novel challenges.The stringent mission requirement to reach a target with a certain precision imposes a high guidance precision.The miniaturization of the size of MMs makes the design of the guidance,navigation,and control(GNC)have a larger-thanbefore impact on the main-body design(shape,motor,and layout design)and its design objective,i.e.,flight performance.Pursuing a trade-off between flight performance and guidance precision,all the relevant interactions have to be accounted for in the design of the main body and the GNC system.Herein,a multi-objective and multidisciplinary design optimization(MDO)is proposed.Disciplines pertinent to motor,aerodynamics,layout,trajectory,flight dynamics,control,and guidance are included in the proposed MDO framework.The optimization problem seeks to maximize the range and minimize the guidance error.The problem is solved by using the nondominated sorting genetic algorithm II.An optimum design that balances a longer range with a smaller guidance error is obtained.Finally,lessons learned about the design of the MM and insights into the trade-off between flight performance and guidance precision are given by comparing the optimum design to a design provided by the traditional approach.展开更多
Loitering munitions are increasingly used in armed conflicts.An extensive database of loitering munitions is developed based on information available in the public domain.This database includes dimensions,weights,and ...Loitering munitions are increasingly used in armed conflicts.An extensive database of loitering munitions is developed based on information available in the public domain.This database includes dimensions,weights,and performance parameters such as flight endurance and communication range.Based upon this dataset,6 categories of loitering munitions are identified and statistical trends in the form of equations are provided for each category.The statistical trends are supported by aircraft performance theory tailored to loitering munitions applications.Altogether,the combination of the database,statistical trends and aircraft performance theory can be used to analyse the flight performance and design considerations of new loitering munitions of which only limited non-technical information is available in the public domain such as pictures and news articles.Based on the statistical trends and aircraft performance theory it is concluded that for long range applications,the preferred design solution is the conventional configuration.The cruciform configuration is beneficial in case precision flight path control is of prime importance.The tandem wing configuration combines the benefits of a canister launch and relatively high aspect ratio wings suitable for long range flight.Finally,the delta wing design provides a large internal volume and a high terminal attack airspeed.Two example case studies are included to illustrate the flight performance capabilities of two types of loitering munitions used in the current conflict in Yemen(a long range conventional design and a delta wing configuration).展开更多
Douchi is a kind of traditional Chinese fermented soybean food.Ultra-high performance liquid chromatography quadrupole-time of flight mass spectrometry(UPLC-QTOF-MS)was applied to separate and identify 12 kinds of iso...Douchi is a kind of traditional Chinese fermented soybean food.Ultra-high performance liquid chromatography quadrupole-time of flight mass spectrometry(UPLC-QTOF-MS)was applied to separate and identify 12 kinds of isoflavones in Douchi within 16 min.The chromatographic separation was carried out on an ACQUITY UPLC HSS T3 column with a gradient elution program where water containing 0.1%formic acid and acetonitrile containing 0.1%formic acid were used as mobile phases.Detection by using electrospray ionization of positive ion mode was applied in the mass spectrometry.Isoflavones were identified by determining the accurate mass and referring to references in this study.展开更多
文摘The design of mini-missiles(MMs)presents several novel challenges.The stringent mission requirement to reach a target with a certain precision imposes a high guidance precision.The miniaturization of the size of MMs makes the design of the guidance,navigation,and control(GNC)have a larger-thanbefore impact on the main-body design(shape,motor,and layout design)and its design objective,i.e.,flight performance.Pursuing a trade-off between flight performance and guidance precision,all the relevant interactions have to be accounted for in the design of the main body and the GNC system.Herein,a multi-objective and multidisciplinary design optimization(MDO)is proposed.Disciplines pertinent to motor,aerodynamics,layout,trajectory,flight dynamics,control,and guidance are included in the proposed MDO framework.The optimization problem seeks to maximize the range and minimize the guidance error.The problem is solved by using the nondominated sorting genetic algorithm II.An optimum design that balances a longer range with a smaller guidance error is obtained.Finally,lessons learned about the design of the MM and insights into the trade-off between flight performance and guidance precision are given by comparing the optimum design to a design provided by the traditional approach.
文摘Loitering munitions are increasingly used in armed conflicts.An extensive database of loitering munitions is developed based on information available in the public domain.This database includes dimensions,weights,and performance parameters such as flight endurance and communication range.Based upon this dataset,6 categories of loitering munitions are identified and statistical trends in the form of equations are provided for each category.The statistical trends are supported by aircraft performance theory tailored to loitering munitions applications.Altogether,the combination of the database,statistical trends and aircraft performance theory can be used to analyse the flight performance and design considerations of new loitering munitions of which only limited non-technical information is available in the public domain such as pictures and news articles.Based on the statistical trends and aircraft performance theory it is concluded that for long range applications,the preferred design solution is the conventional configuration.The cruciform configuration is beneficial in case precision flight path control is of prime importance.The tandem wing configuration combines the benefits of a canister launch and relatively high aspect ratio wings suitable for long range flight.Finally,the delta wing design provides a large internal volume and a high terminal attack airspeed.Two example case studies are included to illustrate the flight performance capabilities of two types of loitering munitions used in the current conflict in Yemen(a long range conventional design and a delta wing configuration).
基金Supported by the Youth Fund Project from Beijing Academy of Agricultural and Forestry Sciences(QNJJ202001)。
文摘Douchi is a kind of traditional Chinese fermented soybean food.Ultra-high performance liquid chromatography quadrupole-time of flight mass spectrometry(UPLC-QTOF-MS)was applied to separate and identify 12 kinds of isoflavones in Douchi within 16 min.The chromatographic separation was carried out on an ACQUITY UPLC HSS T3 column with a gradient elution program where water containing 0.1%formic acid and acetonitrile containing 0.1%formic acid were used as mobile phases.Detection by using electrospray ionization of positive ion mode was applied in the mass spectrometry.Isoflavones were identified by determining the accurate mass and referring to references in this study.
