An IBEM solution to the scattering of plane SH-waves by a lined tunnel in elastic wedge space

The indirect boundary element method （IBEM） is developed to solve the scattering of plane SH-waves by a lined tunnel in elastic wedge space. According to the theory of single-layer potential, the scattered-wave field can be constructed by applying virtual uniform loads on the surface of lined tunnel and the nearby wedge surface. The densities of virtual loads can be solved by establishing equations through the continuity conditions on the interface and zero-traction conditions on free surfaces. The total wave field is obtained by the superposition of free field and scattered-wave field in elastic wedge space. Numerical results indicate that the IBEM can solve the diffraction of elastic wave in elastic wedge space accurately and effi- ciently. The wave motion feature strongly depends on the wedge angle, the angle of incidence, incident frequency, the location of lined tunnel, and material parameters. The waves interference and amplification effect around the tunnel in wedge space is more significant, causing the dynamic stress concentration factor on rigid tunnel and the displacement amplitude of flexible tunnel up to 50.0 and 17.0, respectively, more than double that of the case of half-space. Hence, considerable attention should be paid to seismic resistant or anti-explosion design of the tunnel built on a slope or hillside.

Spatio-temporal characteristics of population and economy in transitional geographic space at the southern end of"Hu Huan-yong Line"

"Hu Huan-yong Line(Hu Line)"depicts a geographical pattern of China’s population distribution.Its essence is the regionality of humanland relationship and reflects basic characteristics and laws of human beings’adaptation to the natural environment.With the development of the times and the progress of modern science and technology,especially the rapid urbanization and construction of transportation network system in China,the connection between economic and geographical space has been continuously strengthened.The geographical transition zones from mountain areas to plains,i.e.,transitional geographical space,have promoted the changes in human-land relationships through population migration and agglomeration.Taking Sichuan-Yunnan provinces at the southern end of Hu Line as study area,this study analyzed the spatial correlation between population distribution and economy in this region,explored the pattern of geographical agglomeration and deagglomeration,and explained the changing characteristics of humanland relationship in transitional geographic space using global Moran’s I index,global regression model(GRM)and geographically weighted regression(GWR).The results show that population and Gross Domestic Product(GDP)have significant spatial dependence to this region,with obvious aggregation in geographical distribution and positive autocorrelation;comparing with the general least square model,the GWR model incorporating spatial effect was more suitable for revealing the distribution characteristics of geographical elements,with fine results and better fitting;the spatial model of population and GDP as well as the spatio-temporal evolution model of their changes,all of them strongly indicated that Normalized Difference Vegetation Index(NDVI)and road density were important factors governing the spatial differentiation of population and economy;under the rapid development of regional economy and continuous evolution of urban-rural relations,rural transformation and spatial reconstruction promoted the change of population migration and agglomeration.

RELAXED ELASTIC LINES OF SECOND KIND ON ORIENTED SURFACE IN MINKOWSKI SPACE

The relaxed elastic line of second kind on an oriented surface in the Minkowski space was defined and for the relaxed elastic line of second kind which is lying on an oriented surface the Euler-Lagrange equations were derived. Furthermore, whether these curves lie on a curvature line or not was investigated and some applications were given.

INTRINSIC EQUATIONS FOR A GENERALIZED RELAXED ELASTIC LINE ON AN ORIENTED SURFACE IN THE GALILEAN SPACE

In this article, we derive the intrinsic equations for a generalized relaxed elastic line on an oriented surface in the Galilean 3-dimensional space G3. These equations will give direct and more geometric approach to questions concerning about generalized relaxed elastic lines on an oriented surface in G3.

Study on Forced Straight-Line Guidance for the Final Translation Phase of Spacecraft Rendezvous

Aimed at the problem of final translation of space rendezvous for the applications such as docking,inspection and tracking,optimal straight-line guidance algorithm based on pulse/continuous low-thrust in the context of Clohessy-Wiltshire dynamics is proposed.Two modes of guidance strategy:varying-speed and fixed-speed approaching scheme for V-bar and R-bar approach by using constant/finite low-thrust propulsion respectively are studied,and the corresponding fuel-optimal conditions are obtained.Numerical simulation is conducted to verify and test the proposed algorithms.The results show that there is generally no different between the fuel consumptions by using the two different approaching modes for V-bar case.However,the conclusion for Rbar case is different that the using of continuous low-thrust cost more fuel and transfer time.

A Characterization of Complex Projective Spaces by Sections of Line Bundles

Let M be a n-dimensional compact irreducible complex space with a line bundle L. It is shown that if M is completely intersected with respect to L and dimH0(M, L) = n + 1, then M is biholomorphic to a complex projective space Pn of dimension n.

Study on the Relationship of Seedling Density and Line Spacing to Leaf-stem Ratio, DW/FW Ratio and Grass Yield of Forage Sweet Sorghum

[ Objectives ] The aim was to optimize the configuration of seedling density and line spacing of forage sweet sorghum （ Sorghum blcolor （ L. ） Moench） and explore its high-yield cultivation techniques. [ Methods] Effects of such two influencing factors as line spacing and seedling density on the leaf-stem ratio, DW/FW ratio and grass yield of forage sweet sorghum were analyzed by using split-plot experiment design experiment method and LSD method of IBM. SPSS. Statis- tics. v22 stati, stics software. [ Results ~ Seedling density and line spacing had no obvious effect on the leaf-stem ratio and DW/FW ratio of forage sweet sorghum but had obvious influences on the grass yield. Moreover, the optimal combination of seedling density and line spacing for high yield of forage sweet sorghum was A2 B4, that is, seedling density was 225 000 plants/hm2, and line spacing was 40 cm. [ Conclusions] The results provided a theoretical basis and technical support for high-yield cultivation techniques of forage sweet sorghum.

Momentum-space crystal in narrow-line cooling of ^(87)Sr

The discovery of the momentum space crystal based on the alkaline-earth atom ^(88)Sr in narrow-line cooling has paved the way to explore this novel physical phenomenon in other cold atom systems. In this paper, a momentum space crystal based on the fermions ^(87)Sr in narrow-line cooling of transition^1S_0–~3P_1 is demonstrated. We theoretically analyze and compare the formation principle of the narrow-line with that of broad-line cooling, and achieve the momentum space crystal in experiment. Beyond that we present a series of numerical calculations of those important parameters which influence the distribution and size of the momentum space crystal. Correspondingly, we vary the values of these parameters in experiment to observe the momentum space crystal evolution and distribution. The experimental results are in conformity with the results of the theoretically numerical calculations. These results and analyses provide a detailed supplementary study on the formation and evolution of momentum space crystal. In addition, this work could also give a guideline on atomic manipulation by narrow-line cooling.

Long-term Integration Ability of the Submillimeter Wave Astronomy Satellite(SWAS)Spectral Line Receivers

The Submillimeter Wave Astronomy Satellite(SWAS)was the first space telescope capable of high spectral resolution observations of terahertz spectral lines.We have investigated the integration ability of its two receivers and spectrometer during five and a half years of on-orbit operation.The CI,O_(2),H_(2)O,and^(13)CO spectra taken toward all observed Galactic sources were analyzed.The present results are based on spectra with a total integration time of up to 2.72×10~4hr(■10~8s).The noise in the spectra is generally consistent with that expected from the radiometer equation,without any sign of approaching a noise floor.This noise performance reflects the extremely stable performance of the passively cooled front end as well as other relevant components in the SWAS instrument throughout its mission lifetime.

Application of the sun line-of-sight vector in the optimal attitude estimation of deep-space probe

This paper proposed an optimal algorithm using the sun line-of-sight vector to improve the probe attitude estimation accuracy in deep-space mission.Firstly,the elaborate analysis of the attitude estimation error from vector observations was done to demonstrate that the geometric relation between the reference vectors is an important factor which influences the accuracy of attitude estimation.Then,with introduction of the sun line-of-sight vector,the attitude quaternion obtained from the star-sensor was converted into a pair of mutually perpendicular reference vectors perpendicular to the sun vector.The normalized weights were calculated according to the accuracy of the sensors.Furthermore,the optimal attitude estimation in the least squares sense was achieved with the quaternion estimation method.Finally,the results of simulation demonstrated the validity of the proposed optimal algorithm based on the practical data of the Deep Impact mission.

HALF-SPACE GREENS'S FUNCTION DUE TO A SPATIALLY HARMONIC LINE LOAD AND SCATTERED FIELDS IN THE FAR FIELD REGION

Half-space Green's function due to a spatially harmonic line load has been expressed as a sum of the full-space Green's functions and a 2-D integral representation of the reflected waves by the free surface of the half-space.By using the obtained half-space Green's function,an integral rep- resentation of the scattered waves by a cylindrical obstacle is then derived.Finally,by analyzing the far-zone behavior of the integrands of the integral representation.the far-field pattern of the scattered waves in a half-space obtained.

基于Edline线特征的图像快速匹配算法

特征分布不均匀或缺乏会严重影响点特征的检测和描述,从而增加图像错误匹配率和降低了计算效率。为了解决这些问题,论文提出了一种基于Edline进行边缘绘制,产生像素链,然后利用最小二乘线拟合方法提取Edline(Lind Band Descriptor)描述子进行图像匹配。实验结果表明:相比较传统的线特征检测算法,该方法能够在一些特征缺乏的场景中有效的提高线特征匹配精度,减少图像匹配时间。

基于CiteSpace的“三生空间”与“三区三线”研究综述

“三生空间”与“三区三线”作为区域空间管控治理的重要手段,二者联系紧密。基于CiteSpace对主题词含“三生空间”“三区三线”的样本文献分别进行图谱可视化与量化分析,从基础数据、研究热点、研究趋势、研究内容等方面进行梳理和对比研究。结果表明:“三生空间”相关研究具有阶段性特征,且阶段性与国家政策相适应,而“三区三线”阶段性不明显;“三生空间”侧重于生态文明建设、主体功能区划,“三区三线”侧重于国土空间用途管制;“三生空间”与“三区三线”优势互补,空间管控应当与国家发展战略相结合;二者关键问题均聚焦在国土空间如何划定上,需要兼顾多方利益,进一步优化技术手段。

THE RELATIONSHIP BETWEEN THE INVASION OF PARAPHARYNGEAL SPACES AND THE INVOLVEMENT OF CERVICAL NODES AND POSTERIOR GROUP CRANIAL NERVES IN NASOPHARYNGEAL CARCINOMA

Two hundred cates of nasopharyngeal carcinoma (NPC) admitted to this department from Feb. 1985 to May. 1988 were analysed according to the CT scanning and clinical findings of the primary lesions prior to radiotherapy. The results showed that involvement of parapharyngeal space was very common in NPC, about 80% (160/200 cases) ; particularly unilateral or bilateral retro-styloid spaces, about 69.5% (139/200 cases). It was proposed that patients with NPC had a high Incidence of ipsilateral cervical node metastasis. Contralateral cervical node metastasis was rare. The development of cervical node metastasto in NPC has two modes: one Is direct Infiltration of the retro-stylold space by the lesion; the other Is along the nasopharyngeal lymphatic rete. The data also showed that patients with NPC who presented symptoms of Ⅸ- Ⅲ cranial nerve paralyses always had ipsilateral or bilateral retro- styloid space Infiltrations.

The Uniform Convergence Topology On Multi-valued Mapping Space

Some convergences of topology are discussed. The definitions of almost uniform convergence topology and compatible topology are given. It is shown that the quasiuniform convergence and generalized uniform convergence have no compatible topology,but the almost uniform convergence has compatible topology. Moreover, the description of all uniform convergence limits and their mutual relation are investigated[1].

The detailed characteristics of positive corona current pulses in the line-to-plane electrodes

The corona current pulses generated by corona discharge are the sources of the radio interference from transmission lines and the detailed characteristics of the corona current pulses from conductor should be investigated in order to reveal their generation mechanism.In this paper,the line-to-plane electrodes are designed to measure and analyze the characteristics of corona current pulses from positive corona discharges.The influences of inter-electrode gap and line diameters on the detail characteristics of corona current pulses,such as pulse amplitude,rise time,duration time and repetition frequency,are carefully analyzed.The obtained results show that the pulse amplitude and the repetition frequency increase with the diameter of line electrode when the electric fields on the surface of line electrodes are same.With the increase of inter-electrode gap,the pulse amplitude and the repetition frequency first decrease and then turn to be stable,while the rise time first increases and finally turns to be stable.The distributions of electric field and space charges under the line electrodes are calculated,and the influences of inter-electrode gap and line electrode diameter on the experimental results are qualitatively explained.

Some Results on B_r-Spaces

In this paper,the following results are obtained: (1) The Sorgenfrey Line is a non-Br-space; (2) We introduce Well-distributed complete spaces and locally Cech complete spaces andprove both the two classes of spacs are Br-spaces. The first result shows that there is the non-Br-space which is paracompact, Lindelof and complete quasi-metric. The second result generalizes theByczowski &. Pol theorem(i. e. Cech-complete spaces are Br-spaces) in two aspects.

Perfect Combination of Architectural Functions and Flow Lines: Study on Roof Garden of Frank Gehry's Walt Disney Concert Hall

By exploring the space and the design techniques of roof garden in Frank Gehry's Walt Disney Concert Hall, this paper made further research on the combination of architectural functions and pedestrian fl ow lines, and attempted to summarize the unique design techniques of Frank Gehry by analyzing his works, improve and develop design theories of roof garden, and attract more attention from the public to roof garden design.

On Optimal Non-Overlapping Segmentation and Solutions of Three-Dimensional Linear Programming Problems through the Super Convergent Line Series

The solutions of Linear Programming Problems by the segmentation of the cuboidal response surface through the Super Convergent Line Series methodologies were obtained. The cuboidal response surface was segmented up to four segments, and explored. It was verified that the number of segments, S, for which optimal solutions are obtained is two (S = 2). Illustrative examples and a real-life problem were also given and solved.

Interference Phase of Neutrino Oscillation in Schwarzschild-de Sitter Space-Time

We study the mass neutrino interference phase in Schwarzschild-de Sitter space time along the null trajectory and the geodesic line and obtain the effects of cosmological constant A on the neutrino oscillation. Firstly, in the high energy limit, we find that the phase along the geodesic keeps the double of that along the null. Secondly, we calculate the phase on the condition that the cosmological constant, A, is a small quantity. The correction of the phase due to A is given. Finally, we calculate the proper oscillation length in Schwarzschild-de Sitter space-time, which increases because of the existence of A, compared with the result in Schwarzschild space-time. All of our results can be reduced to those in Schwarzschild space-time as A approaches to zero.