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Optimal midcourse trajectory cluster generation and trajectory modification for hypersonic interceptions

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Journal of Systems Engineering and Electronics 2017年第6期28卷 1162-1173页

作者： Humin lei Jin Zhou Dailiang Zhai lei shao Dayuan Zhang Air and Missile Defense College Air Force Engineering University Xi’an 710051 China Unit 95948 of the PLA Jiuquan 732750 China

The hypersonic interception in near space is a great challenge because of the target’s unpredictable trajectory, which demands the interceptors of trajectory cluster coverage of the predicted area and optimal trajectory modification capability aiming at the consistently updating predicted impact point(PIP) in the midcourse phase. A novel midcourse optimal trajectory cluster generation and trajectory modification algorithm is proposed based on the neighboring optimal control theory. Firstly, the midcourse trajectory optimization problem is introduced; the necessary conditions for the optimal control and the transversality constraints are ***, with the description of the neighboring optimal trajectory existence theory(NOTET), the neighboring optimal control(NOC)algorithm is derived by taking the second order partial derivations with the necessary conditions and transversality conditions. The revised terminal constraints are reversely integrated to the initial time and the perturbations of the co-states are further expressed with the states deviations and terminal constraints ***, the simulations of two different scenarios are carried out and the results prove the effectiveness and optimality of the proposed method.

关键词： neighboring optimal control(NOC) midcourse guidance trajectory cluster generation optimal trajectory modification

Optimal midcourse trajectory planning considering the capture region

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Journal of Systems Engineering and Electronics 2018年第3期29卷 587-600页

作者： ZHOU Jin shao lei WANG Huaji ZHANG Dayuan lei Humin Air and Missile Defense College Air Force Engineering UniversityXi'an 710051China Unit 95948 of the PLA Jiuquan 732750China

An optimal midcourse trajectory planning approach that considers the capture region（CR） of the terminal guidance is proposed in this article based on the Gauss pseudospectral method（GPM）. Firstly, the planar CR of the proportional navigation in terminal guidance is analyzed and innovatively introduced in the midcourse trajectory planning problems, with the collision triangle（CT） serving as the ideal terminal states parameters of the midcourse phase, and the CR area serving as the robustness against target maneuvers. Secondly, the midcourse trajectory planning problem that considers the path, terminal and control constraints is formulated and the well-developed GPM is used to generate the nominal trajectory that meets the CR demands. The interceptor will reshape the trajectory only when the former CR fails to cover the target, which has loosened the critical demand for frequent trajectory modification. Finally, the simulations of four different scenarios are carried out and the results prove the effectiveness and optimality of the proposed method.

关键词： capture region(CR) collision triangle(CT) midcourse guidance trajectory planning hypersonic interception trajectory modification

Preparation of ultrafine chitosan particles by reverse microemulsion

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China Particuology 2007年第6期5卷 384-390页

作者： Guogen Liu lei shao Fei Ge Jianfeng Chen Key Lab for Nanomaterials Ministry of Education Beijing University of Chemical Technology Beijing 100029 China Research Center of Ministry of Education for High Gravity Engineering and Technology Beijing University of Chemical Technology Beijing 100029 China

Ultrafine chitosan particles were prepared by reverse microemulsion consisting of water, Triton X-100, octanol and cyclohexane. Two methods of preparing ultrafine chitosan particles were adopted and compared using TEM and IR, and possible mechanisms for the formation of ultrafine chitosan particles were proposed. Experimental results show that the method which combined ionic gelation and cross-linking gave uniformly sized chitosan nanoparticles with an average diameter of 92 nm, while the cross-linking without ionic gelation produced spindly chitosan particles with an average length of 943 nm and width of 188 nm.

关键词： Chitosan Ultrafine particles Microemulsion

Synthesis and Photoconductivity of Nanosized Phthalocyanine

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Journal of Materials Science & Technology 2006年第4期22卷 533-535页

作者： Shuguang BIAN Xianggao LI lei shao Jianfeng CHEN Key Lab for Nanomaterials Ministry of Education Beijing University of Chemical Technology Beijing 100029 China College of Chemical Engineering Tianjin University Tianjin 300072 China Research Center of the Ministry of Education for High Gravity Engineering and Technology Beijing University of Chemical Technology. Beijing 100029. China

Functional phthalocyanine （Pc） compounds of H2Pc, TiOPc, FePc and CIAIPc were synthesized with a yield of 46.7%, 91.2%, 37.4% and 34.0%, respectively. Nanosized TiOPc was synthesized via a one-step sol-gel method and effects of surfactant doses, nucleation temperature on TiOPc particle size and photoconductivity were investigated. When re（PEG）： m（TiOPc） was 0.1 and nucleation temperature was 0℃, the as-obtained TiOPc had the smallest particle size and largest specific surface area, which were 60 nm and 83m^2/g, respectively. TiOPc synthesized under these conditions also exhibits excellent photoconductivity with charging potential V0, dark decay speed Rd and energy for half-discharging of potential E1/2 being 1160 V, 30 V/s and 0.6 1x.s, respectively.

关键词： Phthalocyanine Nanosize Synthesis Photoconductivity

Formation of Hengchun Accretionary Prism Turbidites and Implications for Deep-water Transport Processes in the Northern South China Sea

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Acta Geologica Sinica(English Edition) 2021年第1期95卷 55-65页

作者： CUI Yuchi shao lei YU Mengming HUANG Chiyue State Key Laboratory of Marine Geology Tongji UniversityShanghai 200092China Earth Dynamics Research Group The Institute for Geoscience Research(TIGeR)School of Earth and Planetary SciencesCurtin UniversityGPO Box U1987Australia

Located at the end of the northern Manila Trench,the Hengchun Peninsula is the latest exposed part of Taiwan Island,and preserves a complete sequence of accretionary deep-sea turbidite *** with extensive field observations,a’source-to-sink’approach was employed to systematically analyze the formation and evolutionary process of the accretionary prism turbidites on the Hengchun *** at the base of the Hengchun turbidites are abundant mafic normal oceanic crust gravels with a certain degree of *** gravels with U-Pb ages ranging from 25.4 to23.6 Ma are underlain by hundreds-of-meters thickness of younger deep-sea sandstone turbidites with interbedded *** indicates that large amounts of terrigenous materials from both the’Kontum-Ying-Qiong’River of Indochina and the Pearl River of South China were transported into the deep-water areas of the northern South China Sea during the late Miocene and further eastward in the form of turbidity *** turbidity flow drastically eroded and snatched mafic materials from the normal South China Sea oceanic crust along the way,and subsequently unloaded large bodies of basic gravel-bearing sandstones to form turbidites near the northern Manila *** the Philippine Sea Plate drifting clockwise to the northwest,these turbidite successions eventually migrated and,since the Middle Pleistocene,were exposed as an accretionary prism on the Hengchun Peninsula.

关键词： IODP boreholes source-to-sink analysis submarine canyon turbidite sandstones Hengchun Peninsula Taiwan

Sea surface temperature variations in the southwestern South China Sea over the past 160 ka

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Acta Oceanologica Sinica 2007年第2期26卷 49-55页

作者： XIE Hongqin JIA Guodong PENG Ping＇an shao lei State Key Laboratory of Organic Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China State Key Laboratory of Marine Geology Tongji University Shanghai 200092 China

Sea surface temperatures （SSTs） in the southwestern South China Sea have been reconstructed for the past 160 ka using the U37^k paleothermometer from the core MD01 - 2392. The temperature differences between glacial times （ MISs 6 and 2） and interglacial times （ MISs 5.5 and 1） are 2.2 ～ 2.5 ℃. Younger Dryas event during the last deglaciation was documented in both the planktonic foraminiferal δ^18 and SST records. After MIS 5.5, SSTs displayed a progressive cooling from 28.6 to 24.5 ℃ culminating at the LGM. During this gradual cooling period, warm events such as MISs 5.3, 5.1 and 3 were also clearly documented. By comparison of SST between the study core and Core 17954, a pattern of low or no meridional SST gradients during the interglacial periods and high meridional SST gradients during the glacial periods was exhibited. This pattern indicates the much stronger East Asian winter monsoon at the glacial than at the interglacial periods. Spectral analysis gives two prominent cycles：41 and 23 ka, with the former more pronounced, suggesting that SSTs in the southern SCS varied in concert with high-latitude processes through the connection of East Asian winter monsoon.

关键词： sea surface temperature alkenone Late Quaternary South China Sea East Asian monsoon

Measuring Spatio-temporal Characteristics of City Expansion and Its Driving Forces in Shanghai from 1990 to 2015

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Chinese Geographical Science 2017年第6期27卷 875-890页

作者： TIAN Li LI Yongfu shao lei ZHANG Yue Department of Urban Planning Tsinghua University Department of Architecture Shanghai University

Urbanization has both direct and indirect impacts on land use change, and analyzing spatio-temporal characteristics of land use change is essential for understanding these impacts. By comparing Landsat TM images, this paper examines the changes of land use structure and landscape patterns in Shanghai from 1990 to 2015. It finds that the city doubled in size, with the growth of isolated construction land being most significant among eight land use types. A land use change matrix was established and landscape indices were selected to evaluate the change of spatial structure in Shanghai. In order to identify the main driving forces of city expansion in Shanghai, this research ran partial least square regression models to assess the impact of 10 social-economic factors on land use change of Shanghai from 1990 to 2015. It then conducted bivariate correlation analysis to explore the drivers of change of various land use types: urban settlement, rural settlement and isolated construction land. Besides quantitative analysis, this paper analyzes the influence of policy-dimensional factors in land use change. It concludes with future potential research topics on land use change in a rapidly urbanizing context.

关键词： urbanization land use change partial least squares regression driving forces Shanghai

Preparation and characterization of NaY zeolite in a rotating packed bed

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Petroleum Science 2012年第1期9卷 106-109页

作者： Xu Yongquan Cai Lianguo shao lei Chen Jianfeng Research Center of the Ministry of Education for High Gravity Engineering and Technology Beijing University of Chemical TechnologyBeijing 100029China Department of Chemical and Pharmaceutical Engineering Hebei University of Science and TechnologyShijiazhuangHebei 050018China

NaY Zeolite was synthesized in a rotating packed bed （RPB） for the first time. A Si-A1 gel with a specific composition was used as the structure-directing agent. The as-synthesized NaY Zeolite was characterized with scanning electron microscopy （SEM）, X-ray diffraction （XRD） and specific surface area （BET）. The characterization result showed that the NaY Zeolite had a particle size of approximately 200 rim, n（SiO2）/n（Al203） ratio of 5.03, crystallinity of 96% and specific surface area of 714 m2/g. The experimental results indicated that the structure of NaY Zeolite was related to the synthesis conditions （such as reactors, crystallization time and so on）. The micromixing efficiency was proven to be the most important factor for synthesis of NaY Zeolite in the high-gravity environment in RPB.

关键词： NaY zeolite crystallinity high-gravity preparation characterization rotating packed bed

Measurement of mass diffusion coefficients of O_2 in aviation fuel through digital holographic interferometry

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Chinese Journal of Aeronautics 2019年第5期32卷 1184-1189页

作者： Chaoyue LI Weihua LIU Xiaotian PENG lei shao Shiyu FENG Key Laboratory of Aircraft Environment Control and Life Support of Ministry of Industry and Information Technology College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics

The experimental apparatus to measure the mass diffusion coefficients of O2 in aviation fuel was constructed based on the digital holographic interferometry method. The theory of mass diffusion coefficient and interference image processing were introduced in detail. The accuracy of the experiment was verified by measuring the mass diffusion coefficient of 0.33 mol/L KCl in aqueous solution at 298.15 K. The mass diffusion coefficients of O_2 in RP3 and RP5 aviation fuels were measured at temperature from 278.15 K to 333.15 K, and the Arrhenius equation was employed to fit the experimental data. In terms of the Stokes-Einstein equation, the viscosities of these two aviation fuels were tested to estimate the correlation among mass diffusion coefficient, viscosity and temperature. A uniform polynomial calculation correlation was proposed to predict the mass diffusion coefficients of O_2 in both RP3 and RP5 aviation fuels, and its accuracy is considerably higher than that of the Stokes-Einstein equation.

关键词： Aviation fuel Diffusion coefficients Digital holographic interferometry Oxygen Viscosity