By using demand & supply theory to analysis the imbalance problem of our countrys civil aviation transportation market, I pointed out that our current city-pair network can no longer satisfied the market requirement, the key to solve the problem lay in the adjustment of air lines structure.

In the fierce competition, Aotai Electric re-arranges quickly the lines structure to increase quality, promoting manufacturing technology and optimizing performance of welding machines as well as enlarging enterprise size and enhancing competitiveness.

The airfield is recognized according to the parallel lines structure features of main and additional runways and structure feature of Chinese “ri(sun)”, “mu(eye)” words consisting of the runways and the paths connecting with them.

Magnetic field topology and field lines structure in the Dynamic Ergodic Divertor of TEXTOR-94

The structure of cometary dust tails is studied in the frame of mechanical theory with special regards to threedimensional treatment of the problem. We begin with the reexamination of orbit mechanics of cometary particles to derive a set of formulae convenient to subsequent discussions and calculations.Mak- ing use of Hamilton's integral b,we have obtained,for example,the equation of orbit in a vectorial form with generalization respecting to force parameter μ(Part 2).On the basis of Part 2,we consider...

The structure of cometary dust tails is studied in the frame of mechanical theory with special regards to threedimensional treatment of the problem. We begin with the reexamination of orbit mechanics of cometary particles to derive a set of formulae convenient to subsequent discussions and calculations.Mak- ing use of Hamilton's integral b,we have obtained,for example,the equation of orbit in a vectorial form with generalization respecting to force parameter μ(Part 2).On the basis of Part 2,we consider such problems as follows:the relation between initial conditions together with μ and the orbit characteristics;the algorithm for computer-calculation of the motion of particles some interesting features of ele- mentary space distributions vertical motion relative to the comet orbit plane and its implications to the tail structure. Arguments given in §2.5 yield two important results.One is a criterion to check the applicability of the FP(Finson and Probstein)-method.The other con- cerns with the somewhat peculiar structure to appears in the dust tail of comet after perihelion passage,which might be termed as《Neck-line structure(henceforce ab- breviated to NLS)》. In Part 3,we present a new interpretation of the anomalous tails refered to the concept of NLS.A discussion of the development of NLS is given,and it is shown that the emergence and development of NLS can provide an adequate expla- nation for the behaviour of the anomalous tail of C/Arend-Roland,1957 Ⅲ.Fur- thermore,statistical consideration on the visibility of anomalous sunward tail is at- tempted,the result of which also shows that the NLS-interpretation seems to be compatible with the data since 1801. In Part4,we develop a new method for numerical analysis of tail brightness. The basic idea of this method is to combine exact treatment of the motion of a large number of sample particles and counting-technique to estimate the surface brightness integral,taking account of the dust emission characteristics of comets which may be expressed by three source functions,namely,the emission rate N_d(t),the modified size-distribution f(γ;t),and the velocity distribution where Ψ(v;r,t)γ=1-μ). Distribution of tail brightness thus obtained gives essentially the exact solution for the assigned source funtions,in the sense that it is not affected by any auxiliary approximations.Moreover,no difficulties arise in the handling of source functions, because the requisite procedure can be reduced to the sampling of values of relevant parameters;thus the present method is applicable equally well for the case of ani- sotropic emission. In an application of the method for C/Arend-RolandPart4),we suppose that the emission rate varies as the inverse-square of heliocentric distanceN_d(t)∝[rc(t)]~(-2)), and that the velocity distribution is characterized as the isotropic one with a unique speed vo(t,γ).The function f(γ;t)is left as one to be determined through the comparison with observation. The function f(r)for C/Arend-Roland,derived by neglecting its time-dependency, is shown in Fig.16.The corresponding brightness probiles are compared with observed ones in Figs.14 and 15,for Apr.28 and Apr.30,respectively,it is worth noting that both main and anomalous tails have been treated in a unified manner, that is,without any temporal anomalies in emission characteristics. With these results,we conclude:(1)The simple forms presupposed for two functionsN_d(t)and Ψ(v;γ,t))may be well accepted as first approximations;(2) The derived function f(γ)shows its broad peak around γ=0.10～0.12 and possibly a secondary peak around γ～0.015;(3)The present brightness analysis adds support, in a quantitative way,to the NLS-interpretation of the.anomalous tails;(4)More observational data and careful analyses are needed,however,to establish the dust emission characteristics of comets.It is hoped that methods and viewpoints described in the present article may serve as the basis for future investigations.

Many previous literatures considered that the operating frequency of an impulse governed oscillator (IGO) was difficult to be extended to the microwave band. One of the reasons put forward was that the width of the synchronizing pulse must be narrower than 1/5 to 1/3 of the period of the VCO, which was relatively difficult to achieve in the microwave band. Some recent literatures raised an objection to this, but still considered the narrower the synchronizing pulse for a microwave IGO in the case of non-ideal...

Many previous literatures considered that the operating frequency of an impulse governed oscillator (IGO) was difficult to be extended to the microwave band. One of the reasons put forward was that the width of the synchronizing pulse must be narrower than 1/5 to 1/3 of the period of the VCO, which was relatively difficult to achieve in the microwave band. Some recent literatures raised an objection to this, but still considered the narrower the synchronizing pulse for a microwave IGO in the case of non-ideal sample-and-hold, the better. This paper proves that neither of these conclusions is exactly true. In addition, previous literatures also doubted the loop stability of IGO, and held that its phase noise might be greater than that of a common phase lock loop. This paper discusses the problems concerning phase noise and loop stability. Theoretical analysis and an IGO experiment at 3GHz show that a correctly designed microwave IGO has low phase noise, better stability and a simpler, compact strip-line structure. Therefore further advances of the IGO may be expected.

Nova Cygni 1978 was observed from October 11 to December 23, 1978 at the Beijing Observatory with the grating spectrograph attached to the Naysmith focus of the 60/90-cm Schmidt telescope. This paper gives postmaximum photographic magnitudes, identification of the spectral features, emission line structures, intensity ratios of some emission lines and temperatures of the underlying star. The main spectral lines in wavelength range λλ3400—6700 from October 11 to 30 are those of the following...

Nova Cygni 1978 was observed from October 11 to December 23, 1978 at the Beijing Observatory with the grating spectrograph attached to the Naysmith focus of the 60/90-cm Schmidt telescope. This paper gives postmaximum photographic magnitudes, identification of the spectral features, emission line structures, intensity ratios of some emission lines and temperatures of the underlying star. The main spectral lines in wavelength range λλ3400—6700 from October 11 to 30 are those of the following atoms or ions: H, FeⅡ, NⅡ, TiⅡ, [0Ⅰ], [NⅡ], NⅢ. From November 10, lines of [OⅢ], HeⅠ and HeⅡ become visible one after another. The emission line H_α shows three components, of which the most redshifted is the strongest. In turn, each component consists of a number of weak emission peaks. Temperature of the underlying star increases with decline of the nova brightness. The upper limit of temperature may be～120000K.