倾斜台阶重力异常灰色反演

迄今为止,想直接利用某一种重务异常曲线求解台阶是类隐 伏地质体的物性和几何参数是十分困难的,一般只能从异常曲线特征上作定性分析,详细分析了倾斜台阶△ｇ重力异常的理论公式及其特下点列的性质,提出了倾斜台阶的重力异常、规范特征点春序列以及差比变换等新概念,建立了直接利用△ｇ曲线反演倾斜台阶全部未特点及其序以及差比变换街等概念,建立了直接利用△ｇ曲线反演中队全部未知参数的一种新解法－规范特征点序列灰关联     

Automatic searching of control point in NOAA AVHRR image

This paper discusses the approaches for automatical searching of control points in the NOAA AVHRR image on the basis of data rearrangement in the form of latitude and longitude grid. The vegetation index transformation and multi-level matching strategies have been proven effective and successful as the experiments show while the control point database is established.     

椭球的倾斜像面空间透视投影正反解变换

利用矢量方法推出椭球的倾斜像面空间透视投影正解公式, 计算出此正解公式与球体的相应正解公式之间的误差, 并且利用矢量方法导出其相应反解公式。     

Fast transform from geocentric to geodetic coordinates

 A new iterative procedure to transform geocentric rectangular coordinates to geodetic coordinates is derived. The procedure solves a modification of Borkowski's quartic equation by the Newton method from a set of stable starters. The new method runs a little faster than the single application of Bowring's formula, which has been known as the most efficient procedure. The new method is sufficiently precise because the resulting relative error is less than 10⁻¹⁵, and this method is stable in the sense that the iteration converges for all coordinates including the near-geocenter region where Bowring's iterative method diverges and the near-polar axis region where Borkowski's non-iterative method suffers a loss of precision. Received: 13 November 1998 / Accepted: 27 August 1999     

On the adjustment of combined GPS/levelling/geoid networks

A detailed treatment of adjustment problems in combined global positioning system (GPS)/levelling/geoid networks is given. The two main types of `unknowns' in this kind of multi-data 1D networks are usually the gravimetric geoid accuracy and a 2D spatial field that describes all the datum/systematic distortions among the available height data sets. An accurate knowledge of the latter becomes especially important when we consider employing GPS techniques for levelling purposes with respect to a local vertical datum. Two modelling alternatives for the correction field are presented, namely a pure deterministic parametric model, and a hybrid deterministic and stochastic model. The concept of variance component estimation is also proposed as an important statistical tool for assessing the actual gravimetric geoid noise level and/or testing a priori determined geoid error models. Finally, conclusions are drawn and recommendations for further study are suggested. Received: 9 September 1998 / Accepted: 8 June 1999     

双层地基位移和应力场求解

通过对半无限弹性体的通解进行Hankel数值逆变换,得到两层地基内部受有轴对称荷载下的位移和应力解,通过改变参数进行了大量的数值计算,计算结果表明与文献中的研究结果一致,可用于设立于层状地基的桩基沉降计算。     

燃煤过程中有害元素转化机理研究进展

综述了煤中有毒、有害元素经燃烧之后的存在形式与去向,元素在燃烧过程中的热解释放行为及其转化机理;强调煤中无机组分为主要存在许多有毒、爱元素在燃烧过程中会释放出来,然后再分异扩散到各种燃烧产物之中,地民人体廷民危害;指出今后研究不仅限于煤中有毒、有害元素的形成机理,更应侧重对燃烧产物中毒、有害元素的分异与去除方法作进一步的研究与试验,力求使燃煤对环境与人体健康产生的危害降低到最低程度。     

Heating-induced phase transformation in zeolite brewsterite: new 4- and 5-coordinated (Si,Al) sites

The dehydration-rehydration processes and phase transformations of brewsterite (space group P2₁/m, ideal formula (Sr,Ba)Al₂Si₆O₁₆·5H₂O) were studied by single crystal X-ray diffraction on two samples heated in an evacuated capillary for 24 h at 280°C and 330°C, respectively, and then cooled to room temperature. After the data collection, the capillary of the crystal heated at 280°C was broken, the sample was kept at room conditions for one month, and diffraction data were recollected. Brewsterite heated in vacuum at 280°C shows a strong decrease of the unit cell volume (about 10%) and the statistical breaking of the T1-O7-T2 bridge of the 4-ring of the 4²5⁴ PBU. T1 cation, in 31% of cases, migrates to a new tetrahedral site, which shares three vertices with the previously occupied one; the fourth vertex is on the mirror plane, and joins two adjacent layers. T2 cation, in 20% of cases, migrates to a new site, which is characterized by a 5-fold coordination. This coordination polyhedron shares three vertices with the previously occupied tetrahedron; the fourth vertex is on the mirror plane, and joins two adjacent layers; the fifth one is unshared. The formation of these new T-O-T bridges prevents the re-expansion and rehydration of the heated brewsterite; as a consequence, the crystal brought back to room conditions does not show any noticeable structural difference with respect to that heated at 280°C. The exchangeable cations, which occupy only one extraframework site in the untreated brewsterite, spread over several sites. The sample heated at 330°C shows a further decrease in the unit cell volume of about 2% with respect to the sample heated at 280°C, and an increase in the migration percentage of T1 and T2 cations to the new sites. Received: 11 November 1997 / Revised, accepted: 26 June 1998     

Migration from the city to the countryside in Hungary and Poland

After the changes of 1989, urban-to-rural migration in Poland and Hungary remained stable compared to rural-to-urban migration. This was connected to a growing importance of suburbanisation around major Hungarian and Polish cities. Suburban areas around these cities are attracting increasing numbers of migrants from the major cities. Pollution and higher crime rates, as well as rising living costs and increasing uncertainties make many people to decide to leave the city for the surrounding countryside. Not only upper middle-class people move to the suburbs, but also lower status people, for whom life in the big city became too difficult. Long-distance migration from the cities to the rural areas is declining. Economic problems together with low employment opportunities prevent people from making such a move. Though the overall level of urban-to-rural migration did not change too much, this article shows the rapidly increasing importance of suburbanisation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Characteristics of post-socialist urban transformation in East Central Europe

The development of the post-socialist city has already been characterised by substantial restructuring processes. Particular emphasis should be drawn to the take-off of the tertiary sector and the comprehensive blight phenomena in the previously industrial areas. The urban housing sector has witnessed increasing housing affordability problems, a marginalisation of communal housing stock, an increase of segregation and an intensification of the decay in the old housing stock. In all East Central European states the spatial development processes of industry and services within the cities basically show clear parallels to the pattern of urban development in continental Europe. In Hungary housing policy, tenure structure and the level of segregation already show relatively closer similarities to the neoliberal, Anglo–American pattern of development. The other ECE states show closer similarities to the corporatist welfare states of continental Europe. As far as medium-term urban development in East Central Europe is concerned, it is to be assumed that – regardless of the specific path of further development – overall solutions shall not be found for the fundamental problems which are the legacy of the socialist era – the decay of old housing stock, large scale derelict industrial areas and the extent and deficiencies of high-rise housing estates. This revised version was published online in July 2006 with corrections to the Cover Date.