Three-dimensional Electromagnetic Characteristics Analysis of Novel Linear Synchronous Motor under Lateral and Yaw Conditions of MAGLEV

Dynamic stability analysis of superconducting electro-dynamic maglev train under lateral and yawing motion condition is the key research content.The novel three-dimensional electromagnetic model of integrated linear synchronous motor in electro-dynamic maglev train with yawing operation condition is proposed,which can not only simultaneously achieve the propulsion,levitation and guidance performances of maglev vehicle,but also analyze the dynamic stability performance of train with yawing condition.The three-dimensional analytical method is introduced for analyzing the electromagnetic force characteristics of the linear synchronous motor with the yawing operation condition.Firstly,the topology structure and operation principle of the linear synchronous motor with yawing attitude are proposed.Secondly,the three-dimensional analytical model and expressions of electromagnetic characteristics are obtained by equivalent circuit method and Fourier decomposition method,such as levitation force,guidance force,propulsion force and yawing torque,etc.Finally,the three-dimensional electromagnetic characteristics of the linear synchronous motor are calculated under yawing operation conditions of maglev train,and the correctness of the analytical theory is verified by the finite element analysis and measured data on the test line.

Mesoscale and Microphysical Characteristics of a Double Rain Belt Event in South China on May 10–13,2022

A second rain belt sometimes occurs ahead of a frontal rain belt in the warm sector over coastal South China,leading to heavy precipitation.We examined the differences in the mesoscale characteristics and microphysics of the frontal and warm sector rain belts that occurred in South China on May 10–13,2022.The southern rain belt occurred in an environment with favorable mesoscale conditions but weak large-scale forcing.In contrast,the northern rain belt was related to low-level horizontal shear and the surface-level front.The interaction between the enhanced southeasterly winds and the rainfall-induced cold pool promoted the persistent growth of convection along the southern rain belt.The convective cell propagated east over the coastal area,where there was a large temperature gradient.The bow-shaped echo in this region may be closely related to the rear-inflow jet.By contrast,the initial convection of the northern rain belt was triggered along the front and the region of low-level horizontal shear,with mesoscale interactions between the enhanced warm-moist southeasterly airflow and the cold dome associated with the earlier rain.The terrain blocked the movement of the cold pool,resulting in the stagnation of the frontal convective cell at an early stage.Subsequently,a meso-γ-scale vortex formed during the rapid movement of the convective cell,corresponding to an enhancement of precipitation.The representative raindrop spectra for the southern rain belt were characterized by a greater number and higher density of raindrops than the northern rain belt,even though both resulted in comparable hourly rainfalls.These results help us better understand the characteristics of double rain belts over South China.

Dynamic physical characteristics of DC arc on arcing horn for HVDC grounding electrode line

The dynamic physical characteristics of a DC arc on an arcing horn for a high voltage direct current(HVDC)grounding electrode line are significantly different from those of the switching device arc,secondary arc,AC fault arc and pantograph-catenary arc.In this work,an experimental platform for the DC arc on the arcing horn was built,and mechanisms of the arc column short circuit and arc root movement were studied.This work further analyzes the characteristics and mechanisms of the arc motion when wind speed and direction,magnetic field and the expansion angle of the electrode are varied.Arc root movement is more likely to occur at the upper electrode.There is a competitive relationship between arc expansion and the transferring effect.The effect of wind on the arc column is greater than the effect on the arc root.The magnetic field has a significant driving effect on both the arc column and the arc root.The research results provide a comprehensive experimental basis for forther probing the method of DC arc suppression,and the improvement of the arcing horn.

Three-Dimensional and Cross-sectional Characteristics of Normal Grain Growth Based on Monte Carlo Simulation

An appropriate Monte Carlo method was developed to simulate the three-dimensional normal grain growth more completely. Comparative investigation on the three-dimensional and the cross-sectional characteristics of normal grain growth was done. It was found that the time exponent of grain growth determined from cross-section exhibits the same rule of increasing slowly with time and approaching the theoretical value n = 0.5 of steadygrain growth as the three-dimensional (3-D) system. From change of the number of grains per unit area with timemeasured in cross-section, the state of 3-D normal grain growth may be predicted. The gtain size distribution incross-section is different from that in 3-D system and can not express the evolution characteristic of the 3-D distribution. Furthermore, there exists statistical connection between the topological parameters in cross-section and thosein three-dimensions.

THE CHARACTERISTIC FINITE DIFFERENCE METHOD FOR THREE-DIMENSIONAL MOVING BOUNDARY VALUE PROBLEM

The software for oil-gas transport and accumulation is to describe the history of oil-gas transport and accumulation in basin evolution. It is of great value in rational evaluation of prospecting and exploiting oil-gas resources. The mathematical model can be discribed as a coupled system of nonlinear partial differential equations with moving boundary value problem. For a generic case of the three-demensional bounded region, bi this thesis, the effects of gravitation、buoyancy and capillary pressure are considered, we put forward a kind of characteristic finite difference schemes and make use thick and thin grids to form a complete set, and of calculus of vaviations, the change of variable, the theory of prior estimates and techniques, Optimal order estimates in l^2 norm are derived for the error in approximate assumption, Thus we have completely solved the well-known theoretical problem proposed by J. Douglas, Jr.

Analysis on Three-dimensional Structure and Echo Characteristic Quantity of a Supercell Storm

[Objective] The research aimed to study three-dimensional structure and echo characteristic quantity of a supercell storm in central Gansu on May 30,2005.[Method] By monitoring data of Lanzhou CINRAD/CC Doppler radar,the three-dimensional structure characteristics of a rare supercell storm which happened in central Gansu on May 30,2005 were analyzed.We tried to reveal three-dimensional structure and echo characteristic index of supercell storm in the northeast of Qinghai-Tibet Plateau,and find reason of rare heavy hail appearance.[Result] The large-scale strong storm was formed by the common effect of Mongolia cold vortex,low-level jet and ground cold front.When the development of main echo was mature,on reflectivity factor map,it presented obvious inverted 'V' shaped structure in left front of low-level storm,typical hooked and 'person'-type echo characteristics in the right rear.The bounded weak echo zone(vault) in low level corresponded with strong echo overhanging body in high level.It surpassed 60 dBz in the strong reflectivity factor zone.It presented one weak meso-cyclone on corresponding radial velocity map.The jumped increase characteristic of VIL could be as one of indices for judging that hail started to grow.Almost all storms(VILD ≥4.0 g/m3) had more obvious indication significance than VIL for judging heavy hail(diameter ≥20 mm).[Conclusion] The research provided reference for nowcasting of strong convection weather and artificial hail suppression.

CHARACTERISTICS OF THE MERIDIONALLY ORIENTED SHEAR LINES OVER THE TIBETAN PLATEAU AND ITS RELATIONSHIP WITH RAINSTORMS IN THE BOREAL SUMMER HALF-YEAR

In this paper,European Center for Medium-Range Weather Forecasts(ECMWF)Reanalysis-Interim(ERAInterim)data and daily precipitation data in China from May to October during 1981-2016 are used to study the climatic characteristics of the meridionally oriented shear lines(MSLs)over the Tibetan Plateau(TP).The relationship between the MSL and rainstorms in the eastern TP and neighboring areas of the TP during the boreal summer half-year is also investigated.An objective method,which uses a combination of three parameters,i.e.the zonal shear of the meridional wind,the relative vorticity and the zero line of meridional wind,is adopted to identify the shear line.The results show that there are two high-occurrence centers of MSL.One is over the central TP(near 90°E)and the other is over the steep slope area of the eastern TP.Fewer MSLs are found along the Yarlung Zangbo River over the western TP and the southern Tibet.There are averagely 42.2 MSL days in each boreal summer half-year.The number of MSL days reaches the maximum of 62 in 2014 and the minimum of 22 in 2006.July and October witness the maximum of 10.2 MSL days/year and the minimum of 4.2 MSL days/year,respectively.The annual number of the MSL days shows periodicities of 2-4 and 4-6 years,which is quite similar to those of the MSL rainstorm days.In the neighboring areas of the TP,nearly56%of the MSLs lead to rainstorms,and nearly 40%of rainstorms are caused by the MSLs,indicating a close relationship between the MSLs and rainstorms in this region.

Optimized analysis of sharpening characteristics of a compact RF pulse source based on a gyro-magnetic nonlinear transmission line for ultrawideband electromagnetic pulse application

We constructed a compact high-power RF pulse generator based on a gyro-magnetic nonlinear transmission line(GNLTL) to produce a high-voltage pulse with a sub-nanosecond rise time and a relatively high repetition rate, which shows great potential for application in the high-power ultrawideband electromagnetic effect, etc. The influence of incident pulse parameters(rise time and voltage amplitude) and line length on the sharpening characteristics of the GNLTL were investigated experimentally to optimize the rising rate of the modulated pulse front. Based on the GNLTL equivalent circuit model consisting of an LC ladder network, the rise time, the voltage conversion coefficient and the rising rate properties of a modulated pulse were also numerically analyzed in a wider range. The results show that a?>?90 k V RF pulse with a rise time of 350 ps and a repetition rate of 1 kHz in burst mode is produced by the GNLTL at an axial biasing magnetic field of 22 kA m^-1 and a line length of 30 cm under the condition of a 70 kV incident pulse. Applying a faster and higher incident pulse is conducive to improving the sharpening effect of the GNLTL. Furthermore, within a certain range, increasing the line length of the GNLTL not only reduces the rise time, but increases the voltage conversion coefficient and the rising rate of a modulated pulse. Furthermore, considering the energy loss of ferrite rings, there is an optimal line length to obtain the fastest rising rate of a modulated pulse front edge.

Three-Dimensional Conjugate Tooth Surface Design and Contact Analysis of Harmonic Drive with Double-Circular-Arc Tooth Profle

A three-dimensional conjugate tooth surface design method for Harmonic Drive with a double-circular-arc tooth profle is proposed. The radial deformation function of the fexspline (FS), obtained through Finite Element (FE) analysis, is incorporated into the kinematics model. By analyzing the FS tooth enveloping process, the optimization of the overlapping conjugate tooth profle is achieved. By utilizing the hobbing process, the three-dimensional machinable tooth surface of FS can be acquired. Utilizing the coning deformation of the FS, simulations are conducted to analyze the multi-section assembly and meshing motion of the machinable tooth surface. The FE method is utilized to analyze and compare the loaded contact characteristics. Results demonstrate that the proposed design method can achieve an internal gear pair consisting of a circular spline with a spur gear tooth surface and the FS with a machinable tooth surface. With the rated torque, approximately 24% of the FS teeth are engaged in meshing, and more than 4/5 of the tooth surface in the axial direction carries the load. The contact patterns, maximum contact pressure, and transmission error of the machinable tooth surface are 227.2%, 40.67%, and 71.24% of those on the spur gear tooth surface, respectively. It clearly demonstrates exceptional transmission performance.

Nutritional and Technological Characteristics of New Cowpea (<i>Vigna unguiculata</i>) Lines and Varieties Grown in Eastern Kenya

Protein sources in the diet of people living in semi-arid land of Kenya are lacking and if available it is costly to them. In terms of safe food and a healthy food supply, cowpeas (Vigna unguiculata.) are a significant source of protein, carbohydrates, and minerals especially for poor populations in the Kenya, it is said to be poor man’s meat. The aim of this study was to determine nutritional composition of newly bred ten cowpea lines and five varieties commonly grown in Eastern Kenya of Kitui, Machakos and Makueni counties to understand their potential utilization in curbing rising food and nutrition insecurity in arid and semi-arid lands ASALs and in any other food applications in Kenya. The experiment was arranged in Completely Randomized Design (CRD) whereby proximate composition and minerals were determined using standard AOAC and AACC methods and technological characteristics checked using modified methods used by other researchers. Collected data were subjected to Analysis of Variance (ANOVA) using SAS (2006) version 9.1, mean separation was done using Tukey’s Honestly Significant Difference (HSD) method at 5% level of significance. Cowpeas composition ranged from 12.28% - 13.35% for moisture content, 49.37% - 55.74% for total carbohydrates, 2.99% - 3.34% for crude ash, 0.13% - 0.81% for crude lipids, 23.37% - 29.70% for crude protein and 1.40% - 4.34% for crude fibers. Cowpea samples recorded highest percentage of essential amino acids (60.71%) and non-essential amino acids (39.29%). Minerals ranged from 1.97 - 2.69 mg/100g for calcium, 3.23 - 3.90 mg/100g for magnesium, 205.53 - 223.30 mg/100g for sodium, 0.80 - 1.23 mg/100g for zinc, 1071.15 - 1152.62 mg/100g for potassium and 0.62 - 1.06 mg/100g for phosphorus. For technological properties, lines absorbed water equivalent to their weights and they were comparable to varieties grown in the region. From the results it showed that cowpea line IT97K-1042-3, TEXAN PINKIYE, TX123, IT85F-867-5, IT82D-889-1 and IT82D-889 have desirable attributes such as high crude protein contents, good water absorption capacities and volumetric expansion. They compared well with existing K80 variety. These cowpea lines could possibly be bred and combined into a single cowpea line and further improved by breeders to have other good properties such as higher levels of water absorption during soaking hence reduced cooking times. Therefore, this work has shown that cowpea lines developed can be used as food security crop, industrial food applications and enriching foods of low protein like in complementary foods for healthy food supply in Eastern Kenya.

AN APPLICATION OF TOPOLOGICAL ANALYSIS TO STUDYING THE THREE-DIMENSIONAL FLOW IN CASCADES;PART I—TOPOLOGICAL RULES FOR SKIN-FRICTION LINES AND SECTION STREAMLINES

Based on the working of Lighthill and Hunt et al., in the present paper the author has established the topological rules adapting to analysing the skin-friction lines and the section streamlines in cascades. These rules are (1) for a rotor cascade without shroud band, the total number of nodal points equals that the saddle points on the skin-friction line vector fields in eachpitch range; (2) for an annular or straight cascade with no-clearances at blade ends, the total number of saddle points is two more than that of nodal points on the skin-friction line fields in a pitch; (3) the total number of saddles in the secondary flow fields on cross-sections in cascade is one less than that of nodes; (4) in the section streamline vector fields on a meridian surface penetrating a flow passage, and on leading and trailing edge sections, the total number of nodes is equal to that of saddles; (5) on the streamline vector fields of a blade-to-blade surface, the total number of nodes is one less than that of saddles.

One modified method of characteristics used to analyze the multiconductor transmission lines

To solve the coupling effect of multiconductor transmission lines excited by external electromagnetic wave, the modified method of characteristics is proposed. The modified method of characteristics which can compute the terminal induced voltages excited by the external electromagnetic wave when the terminal networks or intereonnection networks contain the dynamic elements is introduced. The simulation results indicate that the modified method can analyze the terminal induced voltages when the terminal networks or the interconnection networks contain the dynamic elements excited by the external electromagnetic wave. And the results are compared with the results acquired by FDTD method, the two results are completely same. So one effective modified method is implemented to compute the transmission lines.

ANALYSIS OF DYNAMIC CHARACTERISTICS FOR RCG LINES USING THEORY OF LADDER NETWORKS

The theory of RC uniform ladder networks based upon the recurrence of voltage and cur-rent functions is extended as a vehicle to analyse the dynamic characteristics of reg lines. Meth-ods for computing the time constants and simplifying the transfer functions for reg lines are alsopresented.

Characteristic fractional step finite difference method for nonlinear section coupled system

For the section coupled system of multilayer dynamics of fluids in porous media, a parallel scheme modified by the characteristic finite difference fractional steps is proposed for a complete point set consisting of coarse and fine partitions. Some tech- niques, such as calculus of variations, energy method, twofold-quadratic interpolation of product type, multiplicative commutation law of difference operators, decomposition of high order difference operators, and prior estimates, are used in theoretical analysis. Optimal order estimates in 12 norm are derived to show accuracy of the second order approximation solutions. These methods have been used to simulate the problems of migration-accumulation of oil resources.

A fast and precise three-dimensional measurement system based on multiple parallel line lasers

This paper conducts a trade-off between efficiency and accuracy of three-dimensional(3 D)shape measurement based on the triangulation principle,and introduces a flying and precise 3 D shape measurement method based on multiple parallel line lasers.Firstly,we establish the measurement model of the multiple parallel line lasers system,and introduce the concept that multiple base planes can help to deduce the unified formula of the measurement system and are used in simplifying the process of the calibration.Then,the constraint of the line spatial frequency,which maximizes the measurement efficiency while ensuring accuracy,is determined according to the height distribution of the object.Secondly,the simulation analyzing the variation of the systemic resolution quantitatively under the circumstance of a set of specific parameters is performed,which provides a fundamental thesis for option of the four system parameters.Thirdly,for the application of the precision measurement in the industrial field,additional profiles are acquired to improve the lateral resolution by applying a motor to scan the 3 D surface.Finally,compared with the line laser,the experimental study shows that the present method of obtaining 41220 points per frame improves the measurement efficiency.Furthermore,the accuracy and the process of the calibration are advanced in comparison with the existing multiple-line laser and the structured light makes an accuracy better than 0.22 mm at a distance of 956.02 mm.

ESTABLISHMENT OF A MAMMARY CANCER CELL LINE Ca 761-86 AND ITS BIOLOGICAL CHARACTERISTICS IN INBRED 615 MICE

A cell line designated as Ca 761-86 has been established from the solid mouse mammary cancer (Ca 761) by suspension culture. It has been passaged for more than 212 generations. Moderate round cells were predominant and most of them were mononuclear. Some characteristics of malignant cells and A-type viral-like particles were observed by electron microscopy. The results of cytochemical studies (DNA, RNA, SDH, 5' AMPase, ACP etc.) were comparable to the ultramicroscopic results. It multiplied approximately 27.4 fold on day 5 with mitotic index reaching 1.8% on day 3. This cell line was a hyperdiploid with karyotype of 45 or 45, -2X, tril2, tri17, +M1-5. Cell agglutination was observed when treated with ConA (≥7 fig, ml). Spontaneous agglutination might also take place without adding any ConA. After 5×106 cells of Ca 761-86 suspension were transplanted into the normal inbred 615 mice by different ways (subcutan eous, intrafoot-pad or intraperitoneal), the transplan lability rate reached 100%. Spontaneous remission was never observed and its metastatic ability reserved. PPLO were not detected. Ca 761-86 may be of value for practical purposes.

A quasi-isentropic model of a cylinder driven by aluminized explosives based on characteristic line analysis

A quasi-isentropic study on the process of driving a cylinder with aluminized explosives was carried out to examine the influence of the aluminum(Al) reaction rate on cylinder expansion and the physical parameters of the detonation products. Based on the proposed quasi-isentropic hypothesis and relevant isentropic theories, the characteristic lines of aluminized explosives driving a cylinder were analyzed,and a quasi-isentropic model was established. This model includes the variation of the cylinder wall velocity and the physical parameters of the detonation products with the Al reaction degree. Using previously reported experimental results, the quasi-isentropic model was verified to be applicative and accurate. This model was used to calculate the physical parameters for cylinder experiments with aluminized cyclotrimethylenetrinitramine explosives with 15.0 % and 30.0 % Al content. The results show that this quasi-isentropic model can be used not only to calculate the cylinder expansion rule or Al reaction degree, but also to calculate the physical parameters of the detonation products in the process of cylinder expansion. For explosives with 15.0 % and 30.0 % Al, 24.3 % and 18.5 % of the Al was found to have reacted at 33.9 μs and 34.0 μs, respectively. The difference in Al content results in different reaction intensity, occurrence time, and duration of two forms of reaction(diffusion and kinetic) between the Al powder and the detonation products;the post-detonation burning reaction between the Al powder and the detonation products prolongs the positive pressure action time, resulting in a continuous rise in temperature after detonation.

ESTABLISHMENT OF A CELL LINE INFECTED WITH SRS MOUSE LEUKEMIA VIRUS AND ITS BIOLOGICAL CHARACTERISTICS

NIH/3T3 cells were infected with a cell-free extract from the mouse SRS ascltic tumor and propagated at vitro. Experimental results showed that type A and type C virus particles were observed in the cytoplasm of infected NIH/ 3T3 cells by electron-microscopy, X-C assay and reverse transcriptase were both positive. Free proviral-DN A of the leukemia vims was found in the infected NIH/3T3 cell by Southern blot hybridization.Morphologically, the NIH/3T3 cells infected in vitro appeared spherical and formed monolayer cell colonies of various sizes after 24 - 48 hours. When the cultured cells were Inoculated into nude mice (BALB/ c, nu nu ) subcutaneously, flbrosarcoma was Induced, 100%. Inoculation of the cell-free extract of the same cultured cells into Inbred SW-1 newborn mice, resulted in the production of lymphocytic leukemia and lymphoma in 52. 3% within 191 days.

ESTABLISHMENT OF A MURINE ASCITES HEPATOMA CELL LINE H_(22)-F_(25)/L AND ITS BIOLOGICAL CHARACTERISTICS

Having been passed for 160 generations, a cell linedesignated as H22-F25/L was established from a murine tumorlymphatic metastatlc model H22-F25 which had been set up in our college. The cell line was in suspension culture with a rapid proliferation and stable growth. The peak tune of cell division and proliferation was 48 and 96 hours after culture. In a week, the cell number was Increased by 25 tunes. H22-F25/L still keeps the features of a poorly differentiated cancer. Its tumor inducing rate (in vivo)was 100% in 615 mice. Lymph node metastasis rate was 50% and pulmonary metastasis rate 10%. H22- F25/ L Is a population of heterogenetlc tumor cells Including 2 stem cell lines (the model number of chromosomes being 43 in 40% tumor cells and 86 in 32%) and some side lines. The common marker chromosomes M1, M2, M3 and M4 were present in all stem and side lines.