Risk Assessment of Coal Mine Water Hazard Based on Three-Dimensional Model of Geology and Underground Space

Mine safety have top-five disasters,which including the water,gas,fire,dust and geological dynamic disaster.The coal mine water disaster is one of the important factors which restricted the development of China’s coal production.It is showed by statistics that 60%of mine accidents are affected by groundwater,which not only result in the production losses,casualties and a variety of

Three-dimensionally ordered macroporous cross-linked polystyrene incorporating functional group via hydrophilic spacer arm

A versatile and effective method for incorporating functional groups on the pore wall of three-dimensionally ordered macroporous cross-linked polystyrene（3DOM CLPS） by hydrophilic spacer arm has been investigated.The 3DOM CLPS with pore size 865 nm was prepared by sacrifice template method.The hydrophilic spacer arm（polyethylene glycol,molecular weight is 600） was grafted to the 3DOM CLPS via nucleophilic substitution reaction.The other side of active hydroxyl can be further converted into a lot of other functional groups.In this report,the chelating ligand 2-mercaptobenzothiazole（MBZ） group was introduced on the end of the PGE chain to evidence the versatile functionalization approach.The functionalized ordered macroporous materials were characterized by FT-IR,element analyzer,SEM.The results reveal that the pores were successfully bonded with 2-mercaptobenzothiazole groups via hydrophilic spacer arms and the original morphology of ordered macroporous materials were remained after functionalization.The MBZ group density is 0.052 mmol/m^2.The functionalized 3DOM CLPS are expected to application as heavy metal ions adsorbent.

Continuous imaging space in three-dimensional integral imaging

We report an integral imaging method with continuous imaging space. This method simultaneously reconstructs real and virtual images in the virtual mode, with a minimum gap that separates the entire imaging space into real and virtual space. Experimental results show that the gap is reduced to 45% of that in a conventional integral imaging system with the same parameters.

Using"Three-dimensional Space Resources"for Fenlong Technology to Improve Grain Econoloy and Expand Human Living Spaces

Fenlong Technology has been applied to increase yield by 20%-50%,improve quality by 5%,and retain water by 100%in 40 kinds of crop cultivated land and saline-alkali land in 26 provinces of China.This paper clarified for the first time the scientific theory system of Fenlong Technology using three-dimensional space resources"Fenlong Agricultural Nature Theory"and the development of the relative"limits"of agricultural growth,which provides a huge power support and natural force for expanding human living spaces.Through inventing and creating a scientific and technological system of farming tools,farming machinery,farming modes,and magic weapons for cultivation,Fenlong Technology can increase grain,promote ecological development,and greatly expand the living spaces of the Chinese nation and achieve sustainable development.Using Fenlong Technology,China has expanded from the current single"cultivated land agriculture"to the"big pattern agriculture"of Fenlong"cultivated land+saline land+degraded grassland+marginal land+desertified land+river water",flexibly used 147 million ha of"three-dimensional space resources"of land,and the newly increased food,meat,and fish can feed 300 million to 400 million people,increased the water storage by 100 billion m^(3),and reduced the collection of groundwater by 20 million to 60 billion m^(3).

Three-Dimensional Space Interpolation of Grey / Depth Image Sequence-A New Technique of Computer Graphics Synthesis

This paper advances a three-dimensional space interpolation method of grey / depth image sequence, which breaks free from the limit of original practical photographing route. Pictures can cruise at will in space. By using space sparse sampling, great memorial capacity can be saved and reproduced scenes can be controlled. To solve time consuming and complex computations in three-dimensional interpolation algorithm, we have studied a fast and practical algorithm of scattered space lattice and that of 'Warp' algorithm with proper depth. By several simple aspects of three dimensional space interpolation, we succeed in developing some simple and practical algorithms. Some results of simulated experiments with computers have shown that the new method is absolutely feasible.

Multiconstraint adaptive three-dimensional guidance law using convex optimization

The traditional guidance law only guarantees the accuracy of attacking a target. However, the look angle and acceleration constraints are indispensable in applications. A new adaptive three-dimensional proportional navigation(PN) guidance law is proposed based on convex optimization. Decomposition of the three-dimensional space is carried out to establish threedimensional kinematic engagements. The constraints and the performance index are disposed by using the convex optimization method. PN guidance gains can be obtained by solving the optimization problem. This solution is more rapid and programmatic than the traditional method and provides a foundation for future online guidance methods, which is of great value for engineering applications.

Obstacle avoidance method of three-dimensional obstacle spherical cap

Focusing on obstacle avoidance in three-dimensional space for unmanned aerial vehicle(UAV), the direct obstacle avoidance method in dynamic space based on three-dimensional velocity obstacle spherical cap is proposed, which quantifies the influence of threatening obstacles through velocity obstacle spherical cap parameters. In addition, the obstacle avoidance schemes of any point on the critical curve during the multi-obstacles avoidance are given. Through prediction, the insertion point for the obstacle avoidance can be obtained and the flight path can be replanned. Taking the Pythagorean Hodograph(PH) curve trajectory re-planning as an example, the three-dimensional direct obstacle avoidance method in dynamic space is tested. Simulation results show that the proposed method can realize the online obstacle avoidance trajectory re-planning, which increases the flexibility of obstacle avoidance greatly.

Three-Dimensional Metacomposite Based on Different Ferromagnetic Microwire Spacing for Electromagnetic Shielding

An electromagnetic shielding metacomposite based on the absorbing mechanism was prepared by weaving ferromagnetic microwires into the three-dimensional(3D)fabric.The influence of the ferromagnetic microwire spacing on electromagnetic shielding performance and the electromagnetic shielding mechanism of 3D metacomposites were studied.The total electromagnetic shielding performance increases with the increase of electromagnetic wave frequency.3D metacomposites based on the absorbing mechanism can avoid the secondary pollution of electromagnetic waves,and have great potential in military,civil,aerospace and other fields.

Constructing Three-Dimension Space Graph for Outlier Detection Algorithms in Data Mining

Outlier detection has very important applied value in data mining literature. Different outlier detection algorithms based on distinct theories have different definitions and mining processes. The three-dimensional space graph for constructing applied algorithms and an improved GridOf algorithm were proposed in terms of analyzing the existing outlier detection algorithms from criterion and theory. Key words outlier - detection - three-dimensional space graph - data mining CLC number TP 311. 13 - TP 391 Foundation item: Supported by the National Natural Science Foundation of China (70371015)Biography: ZHANG Jing (1975-), female, Ph. D, lecturer, research direction: data mining and knowledge discovery.

Three-Dimensional Exact Solution for Dynamic Damped Response of Plates with Two Free Edges

A three-dimensional state space method has been developed for the calculation of dynamic response of plates with two free edges and two simply supported edges.A complex damping model was introduced, then the exact solutions which satisfy all the governing equations and boundary conditions were obtained.In order to overcome the difficulty of satisfying all the stress conditions at free edges, the displacement functions of free edges were assumed.The boundary conditions were strictly satisfied when the convergence rate was good.The computing time was evidently less than that of finite element method.The comparison of the solution with those of finite element method show that there is an excellent agreement for displacements.When the imaginary parts of normal stress deviated, the finite element results showed existence of shear stresses at top and bottom surfaces, and the boundary conditions of FEM model were not strictly satisfied.

Researches on Cartographic Database-Based Interactive Three-Dimensional Topographic Map

With the development of computer graphics, the three-dimensional (3D) visualization brings new technological revolution to the traditional cartography. Therefore, the topographic 3D-map emerges to adapt to this technological revolution, and the applications of topographic 3D-map are spread rapidly to other relevant fields due to its incomparable advantage. The researches on digital map and the construction of map database offer strong technical support and abundant data source for this new technology, so the research and development of topographic 3D-map will receive greater concern. The basic data of the topographic 3D-map are rooted mainly in digital map and its basic model is derived from digital elevation model (DEM) and 3D-models of other DEM-based geographic features. In view of the potential enormous data and the complexity of geographic features, the dynamic representation of geographic information becomes the focus of the research of topographic 3D-map and also the prerequisite condition of 3D query and analysis. In addition to the equipment of hardware that are restraining, to a certain extent, the 3D representation, the data organization structure of geographic information will be the core problem of research on 3D-map. Level of detail (LOD), space partitioning, dynamic object loading (DOL) and object culling are core technologies of the dynamic 3D representation. The object- selection, attribute-query and model-editing are important functions and interaction tools for users with 3D-maps provided by topographic 3D-map system, all of which are based on the data structure of the 3D-model. This paper discusses the basic theories, concepts and cardinal principles of topographic 3D-map, expounds the basic way to organize the scene hierarchy of topographic 3D-map based on the node mechanism and studies the dynamic representation technologies of topographic 3D-map based on LOD, space partitioning, DOL and object culling. Moreover, such interactive operation functions are explored, in this paper, as spatial query, scene editing and management of topographic 3D-map. Finally, this paper describes briefly the applications of topographic 3D-map in its related fields.

圆之缘——中国传统建筑中的圆门窗探源

圆形门和圆形窗是中国传统建筑中典型的形式语言和象征符号,它们随处可见甚至到了泛滥之态,然而这种圆形母题的“中国式样”究竟源自何时、如何发展、意义何在尚未有公论。通过梳理历史文献和相关学者论述,结合传统造型、传统绘画、传统园林建筑等具体案例,试图厘清圆门窗的发展源流、形式特点,以及其在中国传统建筑中的空间和文化意义。

马克思恩格斯城市空间理论的政治哲学意蕴及其现实启示

通过对资本主义社会的整体性考量,马克思和恩格斯将城市空间纳入唯物主义的整体性视野,认为资本逻辑与城市空间具有紧密的关系,资本逻辑所秉持的普遍物化关系与其固有的剥削属性不断形塑着城市空间的面貌,使城市空间呈现资本化和等级化,城市中空间拜物教盛行。资本逻辑对城市空间的形塑潜在意涵着资本对劳动的统摄,以及劳资空间占有的不均衡,体现着最复杂的社会关系和最隐蔽的剥削关系。从对现实城市空间问题的深入批判到对未来理想空间形式和制度形态的科学构想,马克思和恩格斯旨在建构一种回应空间压迫的空间政治哲学话语叙事,即充分激发工人变革现存空间的革命意识,以工人被规训的身体空间为空间革命的基本单元,通过自由人联合的空间实现空间正义,实现人的自由全面发展。今天,马克思和恩格斯的城市空间理论仍具有丰富的价值意蕴,是推进城市空间变革、构建美好城市空间的科学理论指南。

Quadratic Programming-based Approach for Autonomous Vehicle Path Planning in Space

Path planning for space vehicles is still a challenging problem although considerable progress has been made over the past decades.The major difficulties are that most of existing methods only adapt to static environment instead of dynamic one,and also can not solve the inherent constraints arising from the robot body and the exterior environment.To address these difficulties,this research aims to provide a feasible trajectory based on quadratic programming（QP） for path planning in three-dimensional space where an autonomous vehicle is requested to pursue a target while avoiding static or dynamic obstacles.First,the objective function is derived from the pursuit task which is defined in terms of the relative distance to the target,as well as the angle between the velocity and the position in the relative velocity coordinates（RVCs）.The optimization is in quadratic polynomial form according to QP formulation.Then,the avoidance task is modeled with linear constraints in RVCs.Some other constraints,such as kinematics,dynamics,and sensor range,are included.Last,simulations with typical multiple obstacles are carried out,including in static and dynamic environments and one of human-in-the-loop.The results indicate that the optimal trajectories of the autonomous robot in three-dimensional space satisfy the required performances.Therefore,the QP model proposed in this paper not only adapts to dynamic environment with uncertainty,but also can satisfy all kinds of constraints,and it provides an efficient approach to solve the problems of path planning in three-dimensional space.

Swept-Volume Display System Based on Cylindrical Space Projection and Curved Reflectors

In order to achieve a clear and steady swept-volume display,the method of swept-volume display based on cylindrical space projection was presented. One projector generated the image volume in π× 70 mm × 70 mm × 150 mm space. Experimentally,the resolution of images was 800 pixel × 600 pixel × 360 pixel,which resulted in almost 345 million voxels. In order to achieve space voxels with uniform brightness, curved reflectors were also designed. In addition,the match conditions between triangles and the scanning planes in the volume space were classified and a sweptvolume graphics engine based on embedded platform was designed.The image rendering the hardware foundation for three-dimensional( 3D) dynamic images generation was achieved. Demonstrated in the experiments,light source utilization of the second-generation system based on curved mirror is about three times brighter than the firstgeneration 3D minitor based on flat mirror,and this system is able to display color,clear and well-proportioned 3D images in brighter room light.

并列不等直径倒角柱体绕流的数值模拟

为研究间距比和倒角半径对并列不等直径柱体绕流水动力特性的影响,采用大涡模拟(LES)方法,数值模拟3种间距比L/D和5种倒角半径R+并列布置不等直径柱体的三维流场。验证数值方法的准确性,分析柱体后方受力特性、瞬时流场和时均流场的变化情况。结果表明:倒角变化能改善柱体剪切层的分离发展,同时减小柱体所受的阻力和升力,随着R^(+)的增大,3种L/D下大柱的C_(d-ave)和C_(l-rms)总体呈现出减小趋势,最大降幅分别为38.6%和92.3%。L/D变化对柱体后方流场和尾流形态有较大影响,随着L/D的增大依次观察到两柱体后方的2种尾流形态,即偏斜流态和双涡脱落流态。研究结果可为相关工程设计根据不同影响因素选取合适的倒角柱体提供参考。

基坑钢围檩极限承载能力研究

在基坑中,钢支撑的极限承载能力与围檩的受力密切相关。通过精细化数值计算方法研究钢支撑系统特殊节点构造中围檩的极限承载能力。结果表明,伺服支撑直接作用下围檩极限承载力随偏心距增大而降低;伺服系统的端头圆板构造,较钢支撑直接作用下钢围檩的承载力小很多,设置钢垫板以及加密加劲肋可提高端头圆板模型承载能力。总结的经验可供类似工程参考。

圆中园——从圆门(窗)管窥中国园林的符号与空间

圆形门和圆形窗是中国传统园林建筑中典型的形式符号和空间语言,一方面其抽象的几何原型蕴含着极强的理性和哲学意味,另一方面与月亮的形式关联又将之引向诗情画意的移情想象。圆洞门(窗)因其特殊形态成为了中国园林中无可比拟的一种设计语汇,承载了“如画视觉”和“入画行为”的双重属性。通过解析传统园林中具体的圆门(窗)案例,探究其形式渊源、造型操作、符号特征和空间意义,探讨在现代建筑中重构和转译这种古典语汇的可能性。

Reduced Imaging Time and Improved Image Quality of 3D Isotropic T2-Weighted Magnetic Resonance Imaging with Compressed Sensing for the Female Pelvis

This study is to compare three-dimensional(3D)isotropic T2-weighted magnetic resonance imaging(MRI)with compressed sensing-sampling perfection with application optimized contrast(CS-SPACE)and the conventional image(3D-SPACE)sequence in terms of image quality,estimated signal-to-noise ratio(SNR),relative contrast-to-noise ratio(CNR),and the lesions’conspicuous of the female pelvis.Thirty-six females(age:51,28-73)with cervical carcinoma(n=20),rectal carcinoma(n=7),or uterine fibroid(n=9)were included.Patients underwent magnetic resonance(MR)imaging at a 3T scanner with the sequences of 3D-SPACE,CS-SPACE,and twodimensional(2D)T2-weighted turbo-spin echo(TSE).Quantitative analyses of estimated SNR and relative CNR between tumors and other tissues,image quality,and tissue conspicuity were performed.Two radiologists assessed the difference in diagnostic findings for carcinoma.Quantitative values and qualitative scores were analyzed,respectively.The estimated SNR and the relative CNR of tumor-to-muscle obturator internus,tumor-to-myometrium,and myometrium-to-muscle obturator internus was comparable between 3D-SPACE and CS-SPACE.The overall image quality and the conspicuity of the lesion scores of the CS-SPACE were higher than that of the 3D-SPACE(P<0.01).The CS-SPACE sequence offers shorter scan time,fewer artifacts,and comparable SNR and CNR to conventional 3D-SPACE,and has the potential to improve the performance of T2-weighted images.

甘蓝型油菜太空诱变后代农艺性状调查及品质分析

通过对“神舟四号”飞船、第十八颗返回式卫星搭载甘蓝型油菜种子及其后代的初步研究,结果表明:12个搭载品系种子的出苗率、存苗率、结实率和植株性状在当代(SP1)与对照相比均没有明显变化;但在SP2代,通过田间观测、室内考种和品质测试,发现出长果、多果、早花、矮杆、大粒等有利变异株,多头茎、主茎短缩等畸形变异株,还有一些芥酸、硫甙、含油率、蛋白质含量发生改变的变异群体。从后代中有可能选择出有利于育种目标的变异单株或群体。