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Basic Principles of Creating an Expert System for Choosing TemperatureResistant Functional Coatings Designed for Multipurpose U


A Multipurpose Programmable Power Supply for Halogen Lamps


A multipurpose deepwater experimental string for neutrino experiments on Lake Baikal


A multipurpose deepwater experimental string has been developed for testing new promising techniques and performing methodical tasks of deepwater muon and neutrino detection in Lake Baikal.


Immobilization methods that retain the biological activity of nucleic acids and provide an opportunity to use them as multipurpose analytical reagents are described.

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Implications for the flexible design of fermenters for operation in multiuse campaign facilities are discussed.


The potential for chronic effects on human health is also unknown but of increasing concern because of the multiuse character of water, particularly in densely populated, arid areas.


These results provide additional support for the concept that protection of riparian wetlands is an important management strategy for controlling stream water quality in multiuse landscapes.


A large amount of the land surrounding South Holston Reservoir, owned by the USFS, offers public access and multiuse recreation opportunities.


Although the road was decommissioned, a singletrack, multiuse trail was left in its place.

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 In this paper we briefly review the existing types of large radio telescopes and sug gest certain principles to be considered in future design.With these in mind,a new type of telescopes is proposed.This consists of a large central paraboloid and a number of outer rings of discrete antenna elements. Fig.1 shows the arrangement of the paraboloid and one ring.When the two are connected by “correlation technique”,the resulting radiation pattern will be D∞F_1F_2, where F_1,F_2 are the field patterns of the paraboloid... In this paper we briefly review the existing types of large radio telescopes and sug gest certain principles to be considered in future design.With these in mind,a new type of telescopes is proposed.This consists of a large central paraboloid and a number of outer rings of discrete antenna elements. Fig.1 shows the arrangement of the paraboloid and one ring.When the two are connected by “correlation technique”,the resulting radiation pattern will be D∞F_1F_2, where F_1,F_2 are the field patterns of the paraboloid and the ring respectively.By suitably chosing the radius of the paraboloid R_0,the radius of the ring α,and the number of elements in the ring n (R_0 and a being expressed in unit of the working wavelength), one may neglect the influence of the “secondary patterns” in F_2 (which occurs because the aperture of the ring is not full,but discrete).The Fourier transform of D∞F_1F_2 will then be expressed by equation (22) and shown in Fig.3,in which we take the radia tion pattern of the paraboloid to be represented by Λ_2~2 (2πR_0r). When there are N rings with radii α_1=β_1R_0,α_2=β_2R_0,……,α_N=β_NR_0,and when they are connected with the central paraboloid by “correlation technique”,the radiation pattern will be D(r)=C_0[Λ_2(2πR_0r)]~2+CΛ_2(2πR_0r)[A_1J_0(2πα_1r)+A_2J_0(2πα_2r)+ +……+A_NJ_0(2παNr)],(26) where C_0,C,A_0…A_N are constants.The transform of D(r) is then expressed by equa tions (37),(23),and (27),and may be adjusted to the form as shown in Fig.5.We see from the figure that the curve has nonzero values between the zero spatial frequency and the high frequency cutoff.Hence by the principle of “convolution correction” as pointed out by Wild in [11],the pattern may be “transformed” into a desirable one when a correcting function G is applied. To obtain such a curve as in Fig.5,that is,a curve with nonzero values below cutoff,one may choose the parameters β_m=α_m/R_0(m=1,2,…,N) so that the individual Fourier transforms corresponding to the paraboloid and successive rings will overlap in certain spatial frequency ranges.With this condition and the consideration of economy of arrangement,we may determine β_m and hence n_m [eq.(30)]. Table 1 gives the values of β and n as required in such design.In the sixth column of the table,we also give the halfpower beam widths of the resulting patterns when they are corrected to Λ_1~2 (2πR_1r),where R_1=(β_N+1)R_0/2 (unit:R_0/2 minute of arc). For the sake of illustration,we take the total number of the rings N as 6.Denote the Fourier transform of radiation pattern D by (?),which curve is sketched in Fig.5. In the figure,the amplitude of (?) being modified to conform with the curve (?)_1~2 in order to suppress secondary lobes.The reverse transform of (?) is shown in Fig.6,which is the resulting radiation pattern.From it we see that the halfpower beam width is about (200/R_0)′,the secondary lobe is tolerable,but rather broad. For correcting the pattern to Λ_1~2 (Fig.9),one has to find the correcting function G. As was done by Wild in [11],we have calculated the functions (?)=(?) and G in the case of zenith distance z=0.(Figs.7 and 8) Such calculations may be extended to other zenith distances,but the mathematics will be much more tedious. This type of radio telescope has the following essential characters: (1)It may be looked upon as the extension of a large paraboloid in the sense of improving the resolution and the collecting area.The field of application is wider than most of the usual types of large radio telescopes. (2)The system of antennas is good for wide range of wavelength variation. (3)At any stage,it always permits further developement by addition of outer rings. (4)It is advantageous to have the central paraboloid as large as practicable,since the resolving power is proportional to the factor (β_N+1)R_0.For given β_N,the total num ber of elements required in the rings is the same for any R_0. (5)Away from the zenith,while the resolution in horizontal direction remains the same,that in vertical direction gradually deteriorates with the ihcrease of zenith distance. For N=6,the main lobe expands 1.8 times at z=60°,and 3.2 times at z=75°. (6)Beam swinging and scanning present some technical difficulties Owing to the path differences between different elements being functions of both azimuth and eleva tion. (7)The “convolution corrections” of the radiation pattern are different for dif ferent zenith distances.  本文从讨论现有各种大型射电望远镜系统出发,根据技术条件和研究工作的发展趋势,提出在设计中应当考虑的因素.按照这些考虑,提出了由一个中央大型抛物面天线和多个环状分布分立天线组合而成的系统,导出这种组合的设计公式,并以环的数目 N=6为例,计算了具体的天线方向图形空间谱,并算出为了调整方向图形所需的改正曲线,以及通过两种改正方法所得到的图形.这种系统有着多用途的特点.同时它可以适用于很宽的波长范围,而且通过增加环数可以得到不断的发展.文中讨论了这些特点,提出了一些问题,并且对实现这种方案的技术条件作了简要的叙述.  This paper presents a generalpurpose structural analysis program(JIGFEX) for the existing computers made in our country. It can be used to analyse various complex structures in aeronautical, shipbuilding, mechanical and civil engineering. This program is characterized with the following features: (1) multielement technology. (2) multilevel substructuring. (3) the"MasterSlave" relationship among the displacements of various nodes.  为了适应我国现有的计算机条件以实现组合结构计算，本文从实际应用的角度向大家介绍一个多用途的结构分析程序ＪＩＧＦＥＸ。它备有以下功能： （１）多种基本单元进行结构组合． （２）多层分级子结构的交叉组合； （３）结构位移的主──从关系。 本程序可适用于航空、造船、机械、土建工程等方面的组合结构分析。  The recent developments in nuclear technology bring us nearer to the possibility that the well developed thermal converters will play the role as nearbreeders or even breeders. For instance, the U233Th fuel cycle in LWR and HWR is expected to have a breeding ratio approaching or slightly over 1.0, and it is reported that in certain closepacked water lattice the breeding ratio of PnU238 cycle may be as high as 1.08. Thus the nuclear strategies formerly based mainly on the scenarios generally consisting... The recent developments in nuclear technology bring us nearer to the possibility that the well developed thermal converters will play the role as nearbreeders or even breeders. For instance, the U233Th fuel cycle in LWR and HWR is expected to have a breeding ratio approaching or slightly over 1.0, and it is reported that in certain closepacked water lattice the breeding ratio of PnU238 cycle may be as high as 1.08. Thus the nuclear strategies formerly based mainly on the scenarios generally consisting of two different types of reactors, i. e. converters and breeders, may give way to new strategies base on some different concepts taking into consideration the capability to substitute fossil energy sources; for instance, the future nuclear system may consist of low temperature reactors (1st generation) and high temperature reactors (2nd generation) in order to cover more areas in energy markets. The concepts "substitution capability" of reactor types is suggested as an important factor for such strategies and various factors having influences on determination of such "substitution capability" are discussed briefly in this article. The HTGR's, when coupling with new technologies such as longdistance nuclear heat and thermal splitting of water, is found to have the highest "substitution capability" and therefore considered to play an important role in future nuclear systems.  核能技术的最新进展，使成熟的热中子转化堆更接近于可能由其本身承担近增殖甚至增殖堆的任务。例如，据美国报导，轻水堆内采用铀－２３３／钍循环可望获得增殖比ＢＲ＝１．０，在稠密栅内采用钚／铀－２３８循环也有可能获得增殖比 ＢＲ≈１．０８，估计至少可以作为“近增殖堆”运行。因此，原来以核燃料的转化与增殖两类堆型为基础的核能战略，将来可能过渡到以考虑不同的“能源取代率”作为重要因素的新战略；例如核能体系可能由第一代的低温堆与第二代的高温堆所组成，以适应更多领域内的能源需要。本文提出并初步分析了这种考虑“能源取代率”概念进行核能战略分析的基本要素；并认为原已具备高温、多用途与安全性好等特点的高温气冷堆，在解决了远程核能传输与水的热裂解制氢等先进工艺的配合下，若在经济成本方面经过改进，将具有较高的能源取代率，从而可能在未来的核能系统内占据重要地位。   << 更多相关文摘 
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