Calculation and Analysis of Magnetic Field Pattern for TEXT-U Equipment

In this paper, the toroidal field B of a tokamak produced by separate coils has been calculated from the basic electrodynamic theory. As an example, the toroidal magnetic field B(R) in TEXT-U tokamak is plotted, and the curve is fitted well to the analysis formula B(R) = BoRo/R with a precision of several percents.

Some properties on far-field pattern of scattering by penetrable obstacle in ocean waveguide

This paper is concerned with the properties of propagation fax-field patterns corresponding to the scattering of time harmonic acoustic waves by a bounded penetrable obstacle in an ocean waveguide. The sets of solutions to the transmission problem are constructed such that the restriction of these solutions to the boundary of the penetrable obstacle is dense in a Hilbert space. Then conditions under which a set of propagation far-field patterns is complete in a Hilbert space are determined. These properties are important in investigating inverse transmission problems in an ocean waveguide.

SOME PROPERTIES OF FAR FIELD PATTERNS OF ACOUSTIC WAVES IN AN INHOMOGENEOUS MEDIUM

In this paper, by using functional analysis and integral equation method, we obtain some results about the properties of far field of acoustic waves in an inhomogeneous medium. And we also discuss some ill-posed inverse scattering problems by Tikhonov regularization method.

Magnetic Field Configurations Corresponding to Electric Field Patterns That Evoke Long-Term Potentiation Shift Power Spectra of Light Emissions from Microtubules from Non-Neural Cells

Photon counts were measured every 15 ms for 75 s from microtubule-enriched preparations (and nuclei) from mouse melanoma cells during baseline and after 2 min exposures to 1 μT magnetic fields. The magnetic fields were generated from a circular array of solenoids and presented with accelerating or decelerating rotation velocities. The range of photon radiant flux density was in the order of 10-12 W·m-2. Microtubules preparations that had been exposed for only 2 min to a magnetic field configuration corresponding to the electric field pattern that induced long-term potentiation in neural tissue when applied as electric current displayed peaks of spectral power densities within 7 - 8 Hz, 9.5 Hz, 14 - 15 Hz, and 22 Hz bands. The major peak (9.4 Hz) bandwidth was approximately 0.1 Hz. While microtubule preparations exposed for 2 min to a 7 Hz sine-wave or in the absence of a field emitted an overall similar level of spectral power density, the peaks in power density were not present. Treatment with the LTP patterned fields, compared to the baseline or sine-wave fields primarily altered the frequency band in which the amplitude of the photon field was expressed. These results suggest that the photon emissions from microtubule preparations have the capacity to respond to specifically-patterned or geometric shapes of magnetic fields by altering spectral configurations rather than the absolute numbers of photons.

Effect of asymmetrical channel chirping on field intensity patterns of supermodes and modal discrimination in index guided laser arrays

The effect of channel-width chirping on near- and far-field intensity patterns of the six supermodes was investigated. The supermode discrimination was evaluated in various channel-chirped index guided laser arrays. The results show that the linearly channel-chirped laser array has very good supermode discrimination which is better than that of a uniform laser array, the V channel-chirped laser array has the smallest radiation angle of the fundamental supermode among the calculated arrays, and the asymmetrically V channel-chirped array has a very small radiation angle of the fundamental supermode, which is smaller than that of the uniform array and also allows for very good fundamental supermode discrimination against the higher-order supermodes, which is better than that of the V channel-chirped laser array.

Simultaneous Scatterer Shape Estimation and Partial Aperture Far-Field Pattern Denoising

We study the inverse problem of recovering the scatterer shape from the far-field pattern(FFP)in the presence of noise.Furthermore,only a discrete partial aperture is usually known.This problem is ill-posed and is frequently addressed using regularization.Instead,we propose to use a direct approach denoising the FFP using a filtering technique.The effectiveness of the technique is studied on a scatterer with the shape of the ellipse with a tower.The forward scattering problem is solved using the finite element method(FEM).The numerical FFP is additionally corrupted by Gaussian noise.The shape parameters are found based on a least-square error estimator.If eu¥is a perturbation of the FFP then we attempt to find G,the scatterer shape,which minimizes k u¥−eu¥k using the conjugate gradient method for the denoised FFP.

Pattern analysis of a linear dune field on the northern margin of Qarhan Salt Lake,northwestern China

In terms of formation mechanisms of linear dunes,there are open arguments for their widespread distribution and multi-morphological diversities.In order to clarify the formation mechanism of linear dunes of Qarhan Salt Lake,we used pattern analysis method to analyze the statistical characteristics and spatial variation of their pattern parameters.Except at the west-northwest margin,the pattern parameters showed regular spatial variation from the up-middle part towards the downwind end of the dune field.Based on the cumulative probability plots for inter-crest spacing and crest length,we divided the linear dunes into three groups,which corresponding to the three evolution stages of these dunes.The first group comprises erosional relics,with shorter crests,smaller inter-crest spacing and more random dune orientation.The second group comprises dunes whose sand supply is just sufficient to maintain stability and these dunes are approaching the net erosion stage.The crest length and inter-crest spacing of these dunes are much larger than those of the first group,and dune orientation is closer to the resultant drift direction （RDD） .The last group comprises linear dunes that are still undergoing vertical accretion and longitudinal elongation,which follows the RDD of the modern wind regime.The presence of regular spatial variation of pattern parameters and a similar geometry with the vegetated linear dunes suggest that deposition and erosion coexist in the development and evolution of linear dunes of Qarhan Salt Lake,i.e.deposition predominates at the downwind end of linear dunes in the vertical accretion and longitudinal elongation stage,whereas erosion mainly occurs at the upwind end of linear dunes in the degradation stage.Therefore,the formation mechanism of linear dunes in Qarhan Salt Lake can be reasonably explained by the combination of depositional and erosional theories.

A numerical study on pattern selection in crystal growth by using anisotropic lattice Boltzmann-phase field method

Pattern selection during crystal growth is studied by using the anisotropic lattice Boltzmann-phase field model.In the model,the phase transition,melt flows,and heat transfer are coupled and mathematically described by using the lattice Boltzmann(LB)scheme.The anisotropic streaming-relaxation operation fitting into the LB framework is implemented to model interface advancing with various preferred orientations.Crystal pattern evolutions are then numerically investigated in the conditions of with and without melt flows.It is found that melt flows can significantly influence heat transfer,crystal growth behavior,and phase distributions.The crystal morphological transition from dendrite,seaweed to cauliflower-like patterns occurs with the increase of undercoolings.The interface normal angles and curvature distributions are proposed to quantitatively characterize crystal patterns.The results demonstrate that the distributions are corresponding to crystal morphological features,and they can be therefore used to describe the evolution of crystal patterns in a quantitative way.

Dynamic pattern characteristics of fault deformation and gravity field in the development process of Yongdeng M_S=5.8 earthquake

In this paper, the fault deformation abnormality, dynamic evolution features of gravity and vertical deformation field in the seismogenic process of the Yongdeng, Gansu Province earthquake on July 22, 1995 are studied primarily. There appeared α β γ tri stage anomaly at three sites near the epicenter, and there appeared anomalies of step and sudden jump at more than 10 sites in outer region since 1993. The high value area before shock, coseismic effect and process of recovery aftershock were monitored by portable gravity data. Data reflects the changing process of fault movement from the quasi linear to the nonlinear in the near source region during seismogenic development of the Yongdeng earthquake and evolution of gravity field from heterogeneity of seismogenic term to quasi homogeneity of postseismic term. There exists close relationship between strong earthquake and dynamic evolution of regional stress strain field. Considering all above, the experience and lessons in this medium short term prediction test are summarized.

Active Faulting Pattern,Present-day Tectonic Stress Field and Block Kinematics in the East Tibetan Plateau

This paper examines major active faults and the present-day tectonic stress field in the East Tibetan Plateau by integrating available data from published literature and proposes a block kinematics model of the region. It shows that the East Tibetan Plateau is dominated by strike-slip and reverse faulting stress regimes and that the maximum horizontal stress is roughly consistent with the contemporary velocity field, except for the west Qinling range where it parallels the striking of the major strike-slip faults. Active tectonics in the East Tibetan Plateau is characterized by three faulting systems. The left-slip Kunlun-Qinling faulting system combines the east Kunlun fault zone, sinistral oblique reverse faults along the Minshan range and two major NEE-striking faults cutting the west Qinling range, which accommodates eastward motion, at 10--14 mm/a, of the Chuan-Qing block. The left-slip Xianshuihe faulting system accommodated clockwise rotation of the Chuan-Dian block. The Longmenshan thrust faulting system forms the eastern margin of the East Tibetan Plateau and has been propagated to the SW of the Sichuan basin. Crustal shortening across the Longmenshan range seems low （2-4 mm/a） and absorbed only a small part of the eastward motion of the Chuan-Qing block. Most of this eastward motion has been transmitted to South China, which is moving SEE-ward at 7-9 mm/a. It is suggested from geophysical data interpretation that the crust and lithosphere of the East Tibetan Plateau is considerably thickened and theologically layered. The upper crust seems to be decoupled from the lower crust through a decollement zone at a depth of 15-20 kin, which involved the Longmenshan fault belt and propagated eastward to the SW of the Sichuan basin. The Wenchuan earthquake was just formed at the bifurcated point of this decollement system. A rheological boundary should exist beneath the Longmenshan fault belt where the lower crust of the East Tibetan Plateau and the lithospheric mantle of the Yangze block are juxtaposed.

Spiking patterns of a hippocampus model in electric fields

We develop a model of CA3 neurons embedded in a resistive array to mimic the effects of electric fields from a new perspective. Effects of DC and sinusoidal electric fields on firing patterns in CA3 neurons are investigated in this study. The firing patterns can be switched from no firing pattern to burst or from burst to fast periodic firing pattern with the increase of DC electric field intensity. It is also found that the firing activities are sensitive to the frequency and amplitude of the sinusoidal electric field. Different phase-locking states and chaotic firing regions are observed in the parameter space of frequency and amplitude. These findings are qualitatively in accordance with the results of relevant experimental and numerical studies. It is implied that the external or endogenous electric field can modulate the neural code in the brain. Furthermore, it is helpful to develop control strategies based on electric fields to control neural diseases such as epilepsy.

Evolution of spiral wave and pattern formation in a vortical polarized electric field

In this paper, the evolution of the pattern transition induced by the vortical electric field （VEF） is investigated. Firstly, a scheme is suggested to generate the VEF by changing the spatial magnetic field. Secondly, the VEF is imposed on the whole medium, and the evolutions of the spiral wave and the spatiotemporal chaos are investigated by using the numerical simulation. The result confirms that the drift and the breakup of the spiral wave and the new net-like pattern are observed when different polarized fields are imposed on the whole medium respectively. Finally, the pattern transition induced by the polarized field is discussed theoretically.

Study on a new grain-cash cropping pattern in paddy field

We studied a new grain-cash cropping pattern composed of "barley/watermelon + waize-rice", comparing with "barley / watermelon-rice" (CKI), "watermelon-rice", (CK2). The experiment was conducted in CNRRI’s field for 3 yr, employing completely randomized design with three replications, and each plot occupied 207 m~2. The soil in the experiment field contained: N, 2.48 g. kg, quick effective P 4 mg. kg, and quick effective K 53 mg·kg. The varieties tested were Zhemai 2 (barley), Zhemi 1 (watermelon), Suyu 1 (maize), and Shanyou 63 (hybrid rice).

Numerical Simulation of a Domain-Tessellation Pattern on a Spherical Surface Using a Phase Field Model

A numerical simulation scheme is proposed to analyze domain tessellation and pattern formation on a spherical surface using the phase-field method. A multi-phase-field model is adopted to represent domain growth, and the finite-difference method (FDM) is used for numerical integration. The lattice points for the FDM are distributed regularly on a spherical surface so that a mostly regular triangular domain division is realized. First, a conventional diffusion process is simulated using this lattice to confirm its validity. The multi-phase-field equation is then applied, and pattern formation processes under various initial conditions are simulated. Unlike pattern formation on a flat plane, where the regular hexagonal domains are always stable, certain different patterns are generated. Specifically, characteristic stable patterns are obtained when the number of domains, n, is 6, 8, or 12;for instance, a regular pentagonal domain division pattern is generated for n = 12, which corresponds to a regular dodecahedron.

Preparation of patterned boron nanowire films with different widths of unit-cell and their field emission properties

Large-area patterned films of boron nanowires（BNWs） are fabricated at various densities by chemical vapor deposition（CVD）. Different widths of unit-cell of Mo masks are used as templates. The widths of unit-cell of Mo masks are100 μm, 150 μm, and 200 μm, respectively. The distance between unit cells is 50 μm. The BNWs have an average diameter of about 20 nm and lengths of 10 μm–20 μm. High-resolution transmission electron microscopy analysis shows that each nanowire has a β-tetragonal structure with good crystallization. Field emission measurements of the BNW films show that their turn-on electric fields decrease with width of unit-cell increasing.

基于VOF模型的真空引水罐内流动特性

为解决真空引水罐出口气体流出问题,探究罐内气液两相流动机理,基于RNG k-ε湍流模型和VOF模型对真空引水罐进行计算,对不同初始状态下真空引水罐内的气液两相交界面形态、出口管气体流出量以及出口管内流动状态进行分析,讨论了真空引水罐内初始状态对罐内流场的影响,总结了罐内水位对内部流场及出口管的作用关系.结果显示:当初始水位远高于进水管时会大幅优化真空引水罐内流场;与原初始水位相比,罐内气液两相交界面的交互作用减少;气体流出量体积分数峰值从最初的6.916%降至0.106%,平均值从3.442%降至0.027%;出口管流态得到明显改善,顶部低压区域减少.研究结果表明初始水位的变化会影响真空引水罐内流场特性、气体流出量及出口管流态,为深入认识真空引水罐内部流动及真空引水罐的设计提供了数据支撑.

Near-field optical observations of surface plasmon wave interference at subwavelength hole arrays perforated in Au film

We image optical near-field patterns at subwavelength circular hole arrays in Au film by using scanning near-field optical microscopy in near-infrared wavelengths. Periodical oscillation features are found in the near-field images at the air/Au interface and exhibit two typical kinds of standing wave oscillation forms at the wavelengths corresponding to the transmission minimum and maximum in the transmission spectrum, and the latter one originates from the excitation and interference of a surface plasmon wave at the metallic hole arrays. Our work indicates that monitoring optical near-field patterns can help to reveal many interesting properties of surface plasmon waves at metallic nanostructures and understand their underlying physical mechanisms.

Cluster analysis on summer precipitation field over Qinghai-Tibet Plateau from 1961 to 2004

The summer day-by-day precipitation data of 97 meteorological stations on the Qinghai-Tibet Plateau from 1961 to 2004 were selected to analyze the temporal-spatial distribution through accumulated variance,correlation analysis,regression analysis,empirical orthogonal function,power spectrum function and spatial analysis tools of GIS.The result showed that summer precipitation occupied a relatively high proportion in the area with less annual precipitation on the Plateau and the correlation between summer precipitation and annual precipitation was strong.The altitude of these stations and summer precipitation tendency presented stronger positive correlation below 2000 m,with correlation value up to 0.604（α=0.01）.The subtracting tendency values between 1961-1983 and 1984-2004 at five altitude ranges（2000-2500 m,2500-3000 m,3500-4000 m,4000-4500 m and above 4500 m）were above zero and accounted for 71.4%of the total.Using empirical orthogonal function, summer precipitation could be roughly divided into three precipitation pattern fields：the Southeast Plateau Pattern Field,the Northeast Plateau Pattern field and the Three Rivers＇ Headstream Regions Pattern Field.The former two ones had a reverse value from the north to the south and opposite line was along 35°N.The potential cycles of the three pattern fields were 5.33a,21.33a and 2.17a respectively,tested by the confidence probability of 90%.The station altitudes and summer precipitation potential cycles presented strong negative correlation in the stations above 4500 m,with correlation value of-0.626（α=0.01）.In Three Rivers Headstream Regions summer precipitation cycle decreased as the altitude rose in the stations above 3500 m and increased as the altitude rose in those below 3500 m.The empirical orthogonal function analysis in June precipitation,July precipitation and August precipitation showed that the June precipitation pattern field was similar to the July＇s,in which southern Plateau was positive and northern Plateau negative.But positive value area in July precipitation pattern field was obviously less than June＇s.The August pattern field was totally opposite to June＇s and July＇s.The positive area in August pattern field jumped from the southern Plateau to the northern Plateau.

行政区划视角下哈长城市群空间格局演化及优化调控研究

随着城镇化的推进,部分地区行政区划设置制约城市及城市群发展的问题逐渐暴露,行政区划调整成为各级政府解决城市问题的政策工具。从城市群尺度研究城市存在的行政区划问题、统筹优化行政区划格局有助于提高行政区划的全局性和系统性。利用空间场能模型,分析2010-2020年哈长城市群空间格局的演化特征,得出结论:(1)哈长城市群区域发展极化现象严重,长春市、哈尔滨市与其他城市的发展差距进一步扩大,大部分城市的发展处于衰落状态。(2)哈长城市群的总体场能表现为“中西高,东部低”的特征,长春市和哈尔滨市“双核”结构突出,中西部地区形成了城市发展和联系网络,东部、北部地区城市经济发展和联系水平较低。(3)中心城市腹地中,长春市、哈尔滨市约占了城市群60%的腹地。(4)吉林市、四平市、松原市、辽源市、绥化市等地级市发展不足,县级政区腹地被袭夺严重。基于分析结果,提出推进政区“精明收缩”、调整县级行政区划边界、消除政区“飞地”、核心圈层增设市辖区、辐射较弱圈层增设县级市的调整建议,希望能让哈长城市群空间格局更为优化。

Numerical Simulation of Solidification Microstructure and Effects of Phase-field Parameters on Grain Growth Morphologies

By a simple phase field model, a series of numerical simulations of solidification microstructure was performed to show a rich variety of dendritic patterns. At the same time, the relation between the morphology of grain growth and some parameters including the strength of anisotropy, dimensionless latent heat and the size of initial solid zone was studied. It is for the first time that patterns of grain growth were associated with the size of initial solid zone, which is an interesting issue. The possible reason for this may be that variation in the size of initial solid zone may bring about fluctuation of the interface energy, making the interface unstable.