The Unified Representation of Interface Conditionsof Electromagnetic Quantities Using Exterior Differential Forms

A continuity condition of p-forms across a p-dimensional submanifold isderived.The,various interface conditions of electromagnetic quantities are obtained through theapplication of the continuity condition to Minkowski manifold of space-time.     

Application of Fe83Ga17 line to magnetostrictive displacement sensors

The range of magnetostrictive displacement sensors (MDS) is directly determined by the electromagnetic properties of the magnetostrictive line (ML). The small measuring range of domestic MDS is caused by the ML of Fe-Ni. In accordance with the problem,applying the ML of Fe83Ga17to MDS is proposed and the possibility is demonstrated from the point of electromagnetic properties. A magnetic field model based on the fourier analysis and electromagnetic theory is firstly built,which lays a foundation for the research on electromagnetic properties. And then,the distribution of the magnetic field simulated by MATLAB helpful for wiedemann effect is obtained. The feasibility of our scheme is demonstrated by the good effect of echo signal finally.     

Mine transient electromagnetic field multiples phenomenon

In order to accurately calculate the magnetic field parameters of mine transient electromagnetic field based on the former research theory of transient electromagnetic field full-space and half-space combined with transient electromagnetic space applications in mines this article studies the relationship of transient electromagnetic field intensity and half-space transient electromagnetic field and proposes the multiple phenomenon of transient electromagnetic. Research results show that full-space transient electromagnetic field intensity and half-space transient electromagnetic field intensity has multiple phenomenon. They have 2 times relationship in the early stage and have 2.5 times relationship in the late stage. Similarly mine transient electromagnetic field intensity electric field intensity and apparent resistivity calculations also have multiple relationships. Putting forward the multiple phenomenon has important reference value in theory and practice for researching the mine transient electromagnetic field.     

Apply the Hybrid Method of FDTD/MoM to Calculate the Radiation from the Aperture

This paper presents a hybrid method of the Finite-Difference Time-Domain(FDTD) and the method of moment(MoM) to compute the radiation from the aperture.The FDTD is a commonly used electromagnetic simulation way.It can solve the question with complex dielectric,but it is difficult(even cannot) for FDTD to calculate the far field because of large compute time and computer memory.So the authors can make use of the FDTD to get a large number of near electric field intensity,and then use the MoM,which based on electric field integral equation to compute the far field.Using this procedure,the authors solve the radiation of the box with apertures on one or more sides and reduced the compute time and the computer memory.     

电磁场辅助冻结-解冻技术研究进展

介绍了电场、磁场辅助冻结-解冻技术的研究成果,对其作用机理进行了分析,并介绍了电磁场辅助冻结-解冻设备研发现状,展望了电磁场辅助冻结-解冻技术的应用前景,以期为食品冷冻保鲜提供参考借鉴。     

A NEW METHOD BY USE OF MASS AND ACCELARATION PARAMETERS FOR BALANCING THE SHAKING MOMENT OF ARTICULATED MULTI-BAR LINKAGES

In this paper,a new method with general purpose ispresented for balancing the shaking moment of articulated multi-barlinkage.The concept of this method is clear.The moment equation oflinkages is easy to establish and solve.Furthermore its pattern structuremakes it convenient to be programmed.     

The Biological Effects of Low Frequency Electromagnetic Fields on Cells

The biological effects of ELFMES including proliferation and apoptosis of cells as well as the damage of DNA are initially evaluated with the treatment of plant cells and human pulmonary fibroblasts in low frequency magnetic fields with certain intensity and different time intervals in vitro. Cell culture, counting in vitro, fluorescent dyeing analysis and single cell gel electrophoresis are adopted. The results demonstrate that the electromagnetic field with the intensity of 3mT can affect the proliferation and apoptosis of cells significantly.     

Several Matters to be Noticed During the Moment Modulation Design of Prestressed Concrete Frame

The moment modulation of prestressed concrete frame has some differences compared with that of continuous beam.Based on the analysis of ratio of column linear rigidity to beam one,form of load,second moment and plastic hinge in column,this paper is intended to get some helpful advise for moment modulation design.     

Productive Efficiency and Territorial Externalities in Small and Medium‐Sized Industrial Firms: A Dynamic Analysis of the District Effect

A series of works have analysed differential behaviour in terms of productive efficiency between companies inside a hypothetical industrial district and those outside the district. This objective has been addressed using measures of technical efficiency. The results obtained provide valuable information for quantifying the district effect at a given moment in time. However, constant changes in the market and business behaviour mean that it is worthwhile studying the business district effect from a dynamic point of view. In this study, we provide this new vision through the use of Malmquist productivity indices. This methodology enables us to analyse possible differential evolutions by comparing the productive efficiency of companies inside and outside a district over a period of time. An empirical application has been made on a set of small and medium‐sized Spanish ceramic producers during the period of economic expansion between 1996 and 2007.     

A new measurement method for mass property parameters

Mass property parameters (mass, center of mass, moment of inertia) are important technology parameters of aircraft. The traditional mass and center of mass measurement uses centroid units, and the moment of inertia measurement torsion units, which can only get results in installing direction. Because of the structural reasons, there is a need to get all high accurate physical parameters in clamping once. To solve this problem, this study merges centroid units and torsion units into one composite unit, installs a table which can tilt and rotation to measure the moment of inertia in different conditions. The moment of inertia and product of inertia relative to three axis are calculated by the method of coordinate transformation. Measurement theory of mass, center of mass and mass moment of inertia are described, the main reason of causing measurement errors is discussed, and the measurement accuracy affected by tilt error is analyzed.     

氮肥用量和栽插密度对水稻茎秆力学特性的影响研究

以6个抗倒伏性有一定差异的中籼稻品种为材料,设置了3个氮肥水平、3个栽插密度,分别测定了各处理下的茎秆力学特性,分析了氮肥用量和栽插密度对水稻茎秆力学特性的影响。结果表明：在同等密度下,随着施氮量的增加,弯曲应力,株高,基节弯矩,都逐渐增大;而倒伏指数先降低再升高,即中肥区倒伏指数最小,倒伏的可能性最小。在同一施氮水平下,随着栽插密度的减小,基节弯矩,断面模数和倒伏指数先减小后增大,弯曲应力先增大后减小,而折断弯矩却明显增高。即在适宜的施肥水平下,栽插不宜过稀也不宜过密。高肥水平下稀植,低肥水平下密植,都有可能降低倒伏指数。稀植条件下,基节折断弯矩的变化单靠构成茎秆材料的数量来实现;密植条件下,基节折断弯矩的变化是通过断面模数和弯曲应力两因素共同实现的。实际生产中,施氮量既不能过高,也不能过低,而且不同类型的品种,对施氮量和栽插密度的要求有所不同。改进现有高产品种茎秆的质地可能是进一步提高水稻抗倒性的有效途径。     

铝板材电磁超声兰姆波换能器的有限元分析及优化设计

电磁超声兰姆波换能器由于其激发的兰姆波具有多模式、频散性和信号较弱的特点,在一定程度上限制了其发展及应用。针对增强电磁超声兰姆波信号强度问题,提出了一种优化设计方法。通过在永磁铁和线圈之间加入超微晶叠片来减小永磁铁表面的涡流,增加试件中的涡流,同时改善静磁场的分布,从而增强铝板中的信号强度。重点研究了超微晶对电磁超声信号的影响,采用有限元软件进行仿真分析,并进行了实验验证。实验结果表明,该优化方法能够有效增强兰姆波信号强度。     

A Calculating Method for the Crack Tensor of theOrthotropic Rockmass by the Elastic Wave Velocity

A method was proposed for calculating the crack tensor by the elastic wave velocities in the orthotropic rock masses,based on the theoretical relations of crack tensor and compliance tensor and elastic wave velocities,The numerical results show that there is a good correlation with the measured data.     

A Receiving Surface of Perturbative Photon Fluxes in Interaction Between Gravitational Waves and EM Fields

According to Electrodynamics in curved spacetime, the interaction between gravitational waves (GW) and electromagnetic (EM) fields will produce perturbative electromagnetic fields. In a special EM system, namely, a Gaussian beam (Gb) propagating through a static magnetic field, the photon flux along the direction of the electric field of the Gb will be only a pure perturbative photon flux,when a GW propagates along the symmetric axis of a Gaussian beam. Detailed alanysis and calculation of the photon flux along several typical surfaces are performed, and a possible optimum plane which can receive perturbative photons up to 10~4s~(-1) is proposed. It is possible to provide an important method to detection of GW.     

AREA-VECTOR METHOD CALCULATJJNG THE DISPLACEMENTS OF BEAMS AND FRAMES

A new method with which to calculat the displacements of beams and frames is presented. The areas of tending moment diagram of beam or frame and the slope at the origin of the elastic curve are treated as some rotatable vectors with this method. Angular displacement and in-line displacement can be calculated by using the projection and moment of these vectors. This method can be used to calculate displacement of the bar and the bar syttem ( including three dimensional forms. ) , which made from linear or ncnlinear elastic materials. The cross section of the bar is changeable.     

Experimental Study on Moment Modulation of Prestressed Frames

Based on the experimental study of two prestressed frames in redistribution of Internal force, it can be concluded that the dominating influence factors on moment modulation are the relative height of equivalent compression zone, the secondary moment, the ratio of beam rigidity to column and development of cracks in the top of columns.The secondary moment is very important in modulation of frames. Especially, the secondary moment will governing the modulation when the relative height of equivalent compression zone is large enough.     

GIS Partial Discharge Signal and Its Internal Sensor Detection

Partial discharge electromagnetic waves in GIS propagate is not only in the transverse electric and magnetic(TEM)mode, but also in transverse electric(TE) and transverse magnetic(TM)mode. The paper deduces out the mathematic expressions transient field excited by PD in GIS anywhere by using dyadic Green function theory. The contributions of TEM mode and all high order modes in the detecting frequency scope should be taken into consideration when calculating the electric field excited by PD in GIS. In simulative GIS laboratory, the designed inner couplers are superior to other outer sensors in detection of partial discharge. Inner couplers for the GIS model are developed and their frequency responses are analyzed in antenna model. At last the PD pulses excited by man-made defect are detected by inner couplers using high parameters oscilloscope.     

Experimental Study on a Prestressed Frame of Two Spans Under Unsymmetric Load

By the experimental study on a full-dimensioned prestressed frame of two spans, the relative factors are analyzed such as relative height of equivalent compression zone in critical section, secondary moment, ratio of beam rigidity to column and development of cracks in the top of columns etc., which influence the moment distribution of the post-tensioned prestressed concrete frame from the side of internal force redistribution. It is believed that that the factors of relative height of concrete equivalent compression zone and secondary moment influence the moment modulation in most degree, and ratio of column rigidity to beam also plays a part in the moment modulation to some extent. Second, the plastic joints of frame with excessive spans exit in the span which endure the whole load, at last the whole frame is destroyed because of the destruction of the loading frame, the influence to the non-loading span is little.     

不同熔化速率下的电渣重熔过程数值模拟分析

电渣重熔能提高钢锭的质量,从而满足特种行业的需要,其过程伴随着复杂的物理现象,存在着磁流体流动、传热和传质以及电化学等多方面的影响。通过耦合电磁以及流动和温度方程对电渣重熔过程的三维瞬态进行了数学模拟,研究了熔化速率对重熔过程的影响。结果表明：电流密度、焦耳热和电磁力都随着熔化速率的增大而增大,当熔化速率由14.4 kg/h增加到27.0kg/h,电流密度、焦耳热和电磁力最大值的增大比例超过100%。随着熔化速率的增大,温度最大值有小幅的增加,而且速度最大值的增大幅度接近50%;金属熔池深度则由27 mm增大到38 mm,不利于保证铸坯的质量。     

EXPERIMENTAL RESEARCH OF THE MOMENT MODULATION INFLUENCE ON CRACKING AND DEFLECTION OF CONTINUOUS REINFORCED CONCRETE BEAMS UNDER SERVICE LOADS

Through the static tests of five two-span continuous beams with a relatively small steel ratio, the regularity of redistribution of internal forces of continuous beams with moment modulation is studied, and the moment modulation influence on cracking and deflection of continuous reinforced concrete beams under service loads is analyzed in detail. The conclusions obtained may be used as reference materials for drafting of design code considering redistribution of internal forces.