球面场论

本文对分布在球面上的数量场与向量场作了初步研究,得出"分布全球的非O无旋场必有源"和"分布全球的非O无源场必有旋"的结论,并通过投影建立了球面场与平面场的联系。

旋转抛物面天线近焦球面场分析

应用物理光学法和物理绕射理论分析计算了更接近馈源特性设计要求的焦区小球面上的场分量,得到了场分量的振幅、相位分布与反射面尺寸,小球面尺寸、位置的关系,并给出了数值计算结果曲线。

利用最小二乘配置在球面上整体解算GPS应变场的方法及应用

通过对位移与应变微分公式的分析,给出了球坐标系下应用最小二乘配置法由GPS数据整体解算应变场的方法.首先,对模拟数据的理论应变场与采用全部采样数据和随机抽取50%限定采样数据的应变场结果的对比分析,初步验证了最小二乘配置球面整体解应变场方法的有效性.然后,利用1 999～2001和2001～2004两期中国大陆区域网GPS速度场数据给出了基于最小二乘配置球面解获得的应变率场结果,概要分析了此期间中国大陆应变率场的动态变化.最后,讨论了最小二乘配置在球面上计算应变场需要注意的问题和建议.

球面聚焦超声场计算与测量实验

研究了球面聚焦超声场的声压场计算 .应用物理声学方法 ,推导了聚焦超声场声压的积分表达式 ,并通过数值分析法进行了计算和仿真 ,同时讨论了两种特殊情况下的声压近似解析式 .最后推出了测量高强度聚焦超声装置声压的实例 ,其结果与理论仿真结果相近 ,偏差不大于 3 % .

球面势场自由电子模型与C_（60）的电子吸收光谱

将富勒烯Ｃ（６０）中的π电子近似处理为球面势场中运动的自由电子，由此建立了Ｃ（６０）电子吸收光谱波长λ＝１９９２．６ｎｍ／（Ｌ＋１），并对实验观测到的吸收谱带进行了归属指认。

二能级原子在球面波场下的辐射压力

本文从理论上计算了原子在球面波场中的受力情况 ,计算结果表明 ,球面波冷却和捕陷原子的方法具有冷却原子的范围大和捕陷原子的数目多 ,冷却效率高等优点。

球面聚焦声场自易法从GB/T 32522-2016到IEC TS 62903-2018的技术进步

文章叙述了《球面聚焦超声换能器的电声特性和声功率测量》的自易法校准成为国家标准方法后,进而以其为基础在起草国际电工委员会技术规范的过程中,所做的主要技术进步,包括:理论叙述的改进、一些错误概念的修正、最新研究成果的吸纳、全频段实验验证、测量不确定度估计等重要方面。

纸膜双层缺陷检测的视觉成像光场设计

为实现包装盒纸质基底层和透明膜层缺陷的同步检测,开展了对纸和膜缺陷的同步成像研究。首先,分别建立了标准球面积分光场、椭球面积分光场和弧面积分光场模型,并利用COMSOL Multiphysics 5.6对3类光场进行射线仿真,对比分析了球面积分光场下射线角度均匀性及辐照均匀性,通过正交仿真优化椭球面积分光场参数;其次,在椭球面积分光场环境、亮场前打光环境、暗场前打光环境下对包装盒成像。与此同时,对包装盒的油污、抵触、开口、泡皱、破损5项常见缺陷依次进行物理检测和机器视觉检测,验证缺陷成像的有效性。试验结果表明,在椭球面积分光场下成像,图像对纸质基底层缺陷特征、透明膜层缺陷特征均有较好的呈现效果,图像上油污、抵触、开口、泡皱、破损的物理检出率分别为96.2%、92.5%、100%、95%、92%,异常检出率分别为98.6%、97.5%、100%、100%、98.4%,缺陷类别检出率分别为97.6%、96%、100%、97%、96%。研究结果表明,椭球面积分光场光路角度和辐照强度均匀,覆透明膜包装盒的缺陷特征呈现清晰,满足工业生产的检测要求。

鸡胚心脏心电位场电势分布的研究

目的探讨心电位场电势分布的本质。方法在电导率不同的3种液态媒质中,将参比点置于远离心电场源的近零电位处,分别采集60个5日龄鸡胚心脏2组相反方向上若干离场源不同距离的测试点的心电图。结果在2种电导率不同的液态媒质中,4个测试方向上所有采取点都记录到以正波为主的心电图;相同媒质相反方向相同距离点上记录的正立心电图,其R(r)波的振幅无统计学差异(P>0.05)。结论排除了导联参比点对心电标测的影响,以及多腔室壁厚薄的纷扰,心电位场电势一致向外的分布方式,表明心脏电位场不是偶极场,而可能是拟球状面分布的类单源场。

第十三届非物理类专业大学生物理竞赛试题及解答(1996)

第十三届非物理类专业大学生物理竞赛试题及解答（１９９６）试题说明：第一批录取院校的考生全部题必做（满分为１２０分）．第二批录取院校的考生第１２题、第１５题不做，不要求做的题做了也不计入总分（满分为１００分）．一、填空题（共４６分）１．（５分）一飞轮的...

球面高斯随机场像集和图集的Hausdorff测度

本文考虑了单位球面S2上取值于Rd中的球面高斯随机场T={T(t),t∈S^(2)}的像集和图集的Hausdorff测度,其中指数α满足2 <α <4.对S^(2)中每个紧集D,获得了当4 <(α-2)d时,以概率1,有0 <Φ-m(T(D))<∞,其中Φ-m(·)为Hausdorff测度,并且Φ(r)=r4/α-2loglog1/r.同时,也获得了图集的Hausdorff测度,即以概率1,有0 <Φ-m(Gr(T(D)))<∞,其中当(α-2)d <4时,Φ(r)=r^(2+(1-α-2/2)d)(log log1/r)((α-2)d/4);当(α-2)d>4时,Φ(r)=r^(4)/α-2log lor1/r.本文将欧氏空间相关结果推广到了球面情况.

Simulation of thermal field induced by concave spherical transducer in multi-layer media

High intensity focused ultrasound(HIFU)therapy is an effective method in clinical treatment of tumors,in order to explore the bio-heat conduction mechanism of in multi-layer media by concave spherical transducer,temperature field induced by this kind of transducer in multi-layer media will be simulated through solving Pennes equation with finite difference method,and the influence of initial sound pressure,absorption coefficient,and thickness of different layers of biological tissue as well as thermal conductivity parameter on sound focus and temperature distribution will be analyzed,respectively.The results show that the temperature in focus area increases faster while the initial sound pressure and thermal conductivity increase.The absorption coefficient is smaller,the ultrasound intensity in the focus area is bigger,and the size of the focus area is increasing.When the thicknesses of different layers of tissue change,the focus position changes slightly,but the sound intensity of the focus area will change obviously.The temperature in focus area will rise quickly before reaching a threshold,and then the temperature will keep in the threshold range.

Increase in Probability of the Correct Forecast of Tsunami Formation

The presented paper exhibits theory of the ＂gravitational＂ waves propagation near the Earth surface and in the ocean. There was determined an expression ＂gravitational＂ wave which was registered by the gravimeters being placed in several points of the Earth globe. Alteration of gravitational field was accompanied by alteration of the ＂gravitational＂ wave which has the velocity differing from the velocity of seismic waves. The theoretical model was proved by many experiments realized under registration of the underwater earthquake core by tens of gravimeters being placed in the Earth globe different points. The ＂gravitational＂ waves assist to increase the right forecast probability of the beginning tsunami to 50%.

EFFECT OF FEED ARRAY CONFIGURATION ON THE FIELD-OF-VIEW OF RADIO TELESCOPE ANTENNA

Phased Array Feed (PAF) is a small two-dimensional phased array antenna, playing a role as the multi-beam feed for the reflector antenna. The prominent capability of large continuous Field-of-View (FoV) coverage and fast survey speed makes PAF the promising feed for radio telescopes. In this paper, the effect of feed array of PAF on the gain fluctuations over FoV is analyzed on a sim- plified model of the Five-hundred-meter Spherical Aperture radio Telescope (FAST), including illu- mination pattern edge taper, element spacing, element arrangement and element amount. And the differences between rectangular and hexagonal array arrangements are compared. The relationship between the FoV and array configuration are concluded at last.

On the Mystery of the Interpulse Shift in the Crab Pulsar

A new mechanism of radiation emission in the polar gap of a pulsar is proposed. It is the curvature radiation emitted by positrons moving towards the surface of the neutron star along inclined magnetic field and reflected from the surface. Such radiation interferes with transition radiation emitted from the neutron star when positrons hit the surface. Proposed mechanism explains the mystery of the interpulse shift in the Crab pulsar at high frequencies discovered by Moffett and Hankins twenty years ago. We have found also reflected energy flux and spectrum, discussed coherence and disappearance of interpulse shift with increase of frequency.

Analysis of residual gas disturbance on the inner satellite of Inner Formation Flying System

The Inner Formation Flying System （IFFS） consisting of an freely flying in the shield cavity can construct a pure gravity outer satellite and an inner satellite which is a sphere proof mass orbit to precisely detect the earth gravity field. The residual gas in the cavity is a significant disturbance source due to the temperature inhomogeneity and relative motion of the inner satellite. The expressions of the disturbance forces were derived based on the property of rarefied gas, including the radiometer effect and the damping force. According to the current design of IFFS, heat transfer analysis of the cavity and the inner satellite was carried out, and the surface temperature distribution of the cavity and the inner satellite was given. The relative motion of the inner satellite was obtained from the formation control simulation of IFFS. Then the residual gas disturbance was calculated. The disturbance acceleration acting on the inner satellite due to the radiometer effect was on the order of 10^-11 m s^-2 and the damping acceleration was on the order of 10^-15 m s^-2.