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Extraction and Crystal Structure of Karounidiol

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Chinese Journal of Structural Chemistry 2003年第4期22卷 431-434页

作者： CHAOZhi-mao WANGCheng InstituteofChineseMateriaMedica ChinaAcademyofTraditionalChineseMedicineBeijing100700China InstituteofMateriaMedica PekingUnionMedicalCollegeandChineseAcademyofMedicalSciencesBeijing100050China

The title compound of karounidiol (C30H48O2), a main active triterpene component of snakegourd seed, was isolated from unsaponifiable matter of the seed oil of Trichosanthes kirilowii Maxim., and characterized by X-ray diffraction analysis. It crystallizes in orthorhombic system, space group P212121 with C30H48O2CH3OHH2O (C31H54O4), a = 7.515(1), b = 14.407(1), c = 27.799(2) , V = 3009.8(5) 3, Z = 4, dx = 1.087 g/cm3, Mr = 490.77, F(000) = 1088 and = 0.086 mm-1. The final R = 0.0840 and wR = 0.2289 for 2752 observed reflections (|F|2 ≥ 2|F|2). The molecular crystal structure of karounidiol shows relative stereochemistry of (3,13,14, 20)-3,29-dihydroxy-13-methyl-26-norolean-7,9(11)-diene. The molecule is composed of five six- membered rings with ring junctures of A/B trans, C/d trans and d/E cis.

关键词： karounidiol crystal structure Trichosanthes kirilowii triterpene

The effects of corrugation and wing planform on the aerodynamic force production of sweeping model insect wings

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Acta Mechanica Sinica 2005年第6期21卷 531-541页

作者： Guoyu Luo mao Sun Ministry-of-Education Key Laboratory of Fluid Mechanics Institute of Fluid Mechanics Beihang University Beijing 100083 China

The effects of corrugation and wing planform （shape and aspect ratio） on the aerodynamic force production of model insect wings in sweeping （rotating after an initial start） motion at Reynolds number 200 and 3500 at angle of attack 40℃ are investigated, using the method of computational fluid dynamics. A representative wing corrugation is considered. Wing-shape and aspect ratio （AR） of ten representative insect wings are considered; they are the wings of fruit fly, cranefly, dronefly, hoverfly, ladybird, bumblebee, honeybee, lacewing （forewing）, hawkmoth and dragon- fly （forewing）, respectively （AR of these wings varies greatly, from 2.84 to 5.45）. The following facts are shown. （1） The corrugated and flat-plate wings produce approximately the same aerodynamic forces. This is because for a sweeping wing at large angle of attack, the length scale of the corrugation is much smaller than the size of the separated flow region or the size of the leading edge vortex （LEV）. （2） The variation in wing shape can have considerable effects on the aerodynamic force; but it has only minor effects on the force coefficients when the velocity at r2 （the radius of the second ：moment of wing area） is used as the reference velocity; i.e. the force coefficients are almost unaffected by the variation in wing shape. （3） The effects of AR are remarkably small： whenAR increases from 2.8 to 5.5, the force coefficients vary only slightly; flowfield results show that when AR is relatively large, the part of the LEV on the outer part of the wings sheds during the sweeping motion. As AR is increased, on one hand, the force coefficients will be increased due to the reduction of 3-dimensional flow effects; on the other hand, they will be decreased due to the shedding of part of the LEV; these two effects approximately cancel each other, resulting in only minor change of the force coefficients.

关键词： insect flight - Sweeping wing Unsteady aerodynamics Wing corrugation Planform

Lateral Flight Stability of Two Hovering Model Insects

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Journal of Bionic Engineering 2014年第3期11卷 439-448页

作者： Na Xu mao Sun Ministry-of-Education Key Laboratory of Fluid Mechanics Beihang University Beijing 100191 P. R. China

The longitudinal disturbance motion of different insects at hovering flight has the same modal structure. Here, we consider the case of lateral motion. The lateral dynamic flight stability of two model insects, hoverfly and honeybee, at hovering flight is studied. The method of computational fluid dynamics is applied to compute the stability derivatives. The techniques of eigenvalue and eigenvector analysis are used to solve the equations of motion. Results show that the lateral disturbance motion of the hoverfly has three natural modes of motion： an unstable divergence mode, a stable oscillatory mode and a stable subsidence mode, and the flight is unstable; while the honeybee has a different modal structure （a stable slow subsidence mode, a stable fast subsidence mode, and a nearly neutrally stable oscillatory mode） and the flight is nearly neutrally stable. The change in modal structure between the two insects is due to their roll-moment/side-velocity derivative having different sign, and the sign difference is because that the hoverfly has a relatively small, but the honeybee has a relatively large, distance between the wing roots and the center of mass. Thus, unlike the case of longitudinal motion, for lateral motion, some insects have different modal structures and stability properties from others.

关键词： insect hovering flight dynamic flight stability modal structure

Wing kinematics measurement and aerodynamics of free-flight maneuvers in drone-flies

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Acta Mechanica Sinica 2010年第3期26卷 371-382页

作者： Yanlai Zhang mao Sun Ministry-of-Education Key Laboratory of Fluid Mechanics Institute of Fluid Mechanics Beihang University 100191 Beijing China

The time courses of wing and body kinematics of two free-flying drone-flies, as they performed saccades, were measured using 3d high-speed video, and the morpho- logical parameters of the wings and body of the insects were also measured. The measured wing kinematics was used in a Navier-Stokes solver to compute the aerodynamic forces and moments acting on the insects. The main results are as following. （1） The turn is mainly a 90° change of heading. It is made in about 10 wingbeats （about 55 ms）. It is of interest to note that the number of wingbeats taken to make the turn is approximately the same as and the turning time is only a little different from that of fruitflies measured recently by the same approach, even if the weight of the droneflies is more than 100 times larger than that of the fruitflies. The long axis of body is about 40° from the horizontal during the maneuver. （2） Although the body rotation is mainly about a vertical axis, a relatively large moment around the yaw axis （axis perpendicular to the long axis of body）, called as yaw moment, is mainly needed for the turn, because moment of inertial of the body about the yaw axis is much larger than that about the long axis. （3） The yaw moment is mainly pro- duced by changes in wing angles of attack： in a right turn, for example, the dronefly lets its right wing to have a rather large angle of attack in the downstroke （generally larger than 50°） and a small one in the upstroke to start the turn, and lets its left wing to do so to stop the turn, unlike the fruitflies who generate the yaw moment mainly by changes in the stroke plane and stroke amplitude.

关键词： drone-fly - Maneuver Wing kinematicsmeasurement Aerodynamics Navier-Stokes simulation

Forward flight of a model butterfly: Simulation by equations of motion coupled with the Navier-Stokes equations

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Acta Mechanica Sinica 2012年第6期28卷 1590-1601页

作者： Hua Huang mao Sun Ministry-of-Education Key Laboratory of Fluid Mechanics. Beihang University

The forward flight of a model butterfly was stud- ied by simulation using the equations of motion coupled with the Navier-Stokes equations. The model butterfly moved under the action of aerodynamic and gravitational forces, where the aerodynamic forces were generated by flapping wings which moved with the body, allowing the body os- cillations of the model butterfly to be simulated. The main results are as follows：（1） The aerodynamic force produced by the wings is approximately perpendicular to the long-axis of body and is much larger in the downstroke than in the up- stroke. In the downstroke the body pitch angle is small and the large aerodynamic force points up and slightly backward, giving the weight-supporting vertical force and a small neg- ative horizontal force, whilst in the upstroke, the body an- gle is large and the relatively small aerodynamic force points forward and slightly downward, giving a positive horizon- tal force which overcomes the body drag and the negative horizontal force generated in the downstroke. （2） Pitching oscillation of the butterfly body plays an equivalent role of the wing-rotation of many other insects. （3） The body-mass- specific power of the model butterfly is 33.3 W/kg, not very different from that of many other insects, e.g., fruitflies and dragonflies.

关键词： Butterfly Forward flight - Unsteady aerody-namics - Equations of motion Navier-Stokes equations

development of coal geological information technologies in China

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International Journal of Coal Science & Technology 2020年第2期7卷 320-328页

作者： Shanjun mao School of Earth and Space Sciences Peking UniversityBeijing100871China

The history of coalfield geology and mine geology IT applications is over 30 years,which is gaining remarkable *** paper sheds light on the development of geological and surveying spatial management information ***,this study proposed the development trend,system structure and function design and sub-systems of the new generation of geological and surveying spatial management information system by benefitting from the recent advancements in computer and spatial information *** sub-systems include the“One Map”online collaborative(2d-GIS)management platform,the geological survey mapping collaborative management system,the integrated service system based on“one map”,the three-dimensional dynamic geological model system,the three-dimensional transparent management platform,and water prevention and control information management *** work is an important foundation to realize the IT information and intelligent management of coal *** successful development and application of the new generation of geological and surveying spatial management information system will provide the dynamic data support for the online decision-making of the intelligent coal mining.

关键词： Coalfield geology Mine geology IT application Intelligent mining

Aerodynamic Interactions Between Wing and Body of a Model Insect in Forward Flight and Maneuvers

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Journal of Bionic Engineering 2013年第1期10卷 19-27页

作者： Bin Liang mao Sun Ministry-of-Education Key Laboratory of Fluid Mechanics Beihang University Beoing 100191 P. R. China

The aerodynamic interactions between the body and the wings of a model insect in forward flight and maneuvers are studied using the method of numerically solving the Navier-Stokes equations over moving overset grids. Three cases are con- sidered, including a complete insect, wing pair only and body only. By comparing the results of these cases, the interaction effect between the body and the wing pair can be identified. The changes in the force and moment coefficients of the wing pair due to the presence of the body are less than 4.5% of the mean vertical force coefficient of the model insect; the changes in the aero- dynamic force coefficients of the body due to the presence of the wings are less than 5.0% of the mean vertical force coefficient of the model insect. The results of this paper indicate that in studying the aerodynamics and flight dynamics of a flapping insect in forward flight or maneuver, separately computing （or measuring） the aerodynamic forces and moments on the wing paig and on the body could be a good approximation.

关键词： insect wing-body aerodynamic interaction forward flight maneuvers Navier-Stokes simulation

Application of material-mesh algebraic collapsing acceleration technique in method of characteristics——based neutron transport code

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Nuclear Science and Techniques 2021年第8期32卷 95-109页

作者： Ming dai mao-Song Cheng Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China CAS Innovative Academies in TMSR Energy System Chinese Academy of SciencesShanghai 201800China

The algebraic collapsing acceleration(ACA)technique maximizes the use of geometric flexibility of the method of characteristics(MOC).The spatial grids for loworder ACA are the same as the high-order transport,which makes the numerical solution of ACA equations costly,especially for large-size *** speed-up the MOC transport iterations effectively for general geometry,a coarse-mesh ACA method that involves selectively merging fine-mesh cells with identical materials,called material-mesh ACA(MMACA),is *** energy group batching(EGB)strategy in the tracing process is proposed to increase the parallel efficiency for microscopic crosssection *** and macroscopic crosssection benchmark problems are used to validate and analyse the accuracy and efficiency of the MMACA *** maximum errors in the multiplication factor and pin power distributions are from the VERA-4 B-2 d case with silver-indium-cadmium(AIC)control rods inserted and are 104 pcm and 1.97%,*** with the single-thread ACA solution,the maximum speed-up ratio reached 25 on 12 CPU cores for microscopic cross-section VERA-4-2 d *** the C5 G7-2 d and LRA-2 d benchmarks,the MMACA method can reduce the computation time by approximately one *** present work proposes the MMACA method and demonstrates its ability to effectively accelerate MOC transport iterations.

关键词： Algebraic collapsing acceleration Material-mesh ACA Method of characteristics OpenMP Arbitrary geometry

ELECTRIC HEXAdECAPOLE OF 3d ELECTRON CLOUd OF Ti^(3+) ION

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Chinese Physics Letters 1989年第9期6卷 401-404页

作者： mao Xi'an Coordination Chemistry Institute Nanjing UniversityNanjing

The concept of electric hexadecapole is adopted to d electron clouds of transition *** analogous treatment of nuclear electric hexadecapole internetion with the surrounding electric field,the ligand field splittings of d orbitals is the electric hexadecapole *** electric hexadecapole moment of 3d electron cloud of Ti^(3+) ion has been evaluated as 2.5×10^(-50)C·m^(4).

关键词： splitting analogous internet