四川省巫山县两个村的贫富差距

1979年后,城镇经济的辐射,交通运输的发展,激发了兴胜人的致富动机,75％的农民成为多重职业者,人的素质及经营能力得到提高。这是兴胜脱贫致富的重要原因。庙堂这样的贫困村要脱贫致富,一是依靠政策;三是依靠科技;三是依靠投入,以便改善自然-社会环境;四是依靠服务。在开发资源、发展经济的过程中,提高人的素质和经营能力,落后村庄的脱贫致富是有望的。     

城市水环境"红黄绿"分区整治规划的方法研究——以长春市为例

对城市水环境实行“红黄绿”分区整治规划,目的在于综合考虑各水层水质水量开采现状、污染程度、工业布局、农业灌溉城市发展规划及水源地保护目标等因素,突出主要矛盾,分期分区整治,使之既符合经济技术约束原则,又强化了目标管理。该方法现代化城市的水环境保护与治理具有较强的可操作性和实际意义。     

金沙江干流水电工程区岸坡失稳危险性预测及防治对策

笔者通过调查研究和综合分析金沙江干流水电工程区岸坡地质背景和岩体力学环境条件，定性分析与定量评价相结合，采用与三峡工程库区岸坡失稳危险性评价相类比的方法，针对崩滑体失稳按总体积的1／8和1／11入江方量进行了计算和按美国土木工程学会涌浪图解计算法计算了入水点及在向家坝坝址、溪洛渡坝址和邻近城镇的涌浪高度，并围绕大坝施工安全、库区周边城镇安全，水库运营安全等方面对岸坡失稳的危险性进行了评价预测，提出了岸坡失稳的防治对策。评价结果表明，向家坝库区和溪洛渡库区土质岸坡坍塌及崩滑体入江和涌浪不会影响水库的正常运行及长期效益。     

内陆单斜构造内咸水入侵淡水含水层三维数值模拟：——以山西柳林？…

本文建立了内陆单斜构造内咸水入侵淡水含水层的三维可混溶溶质运移模型。同时,为了尽可能提高模拟精度,还建立了区域二维水流模型和水质模型,为三维模型提供边界条件。模型应用于描述柳林电厂水源地咸－淡水界面运移特征,模拟效果良好,还据此预报了咸水入侵的可能性并探讨了淡水流的强弱对咸－淡水界面运移的影响。     

Engineering Strategies on Flood Control in Middle Reach of Yangtze River, China

CAUSE FOR FL OODS IN MIDDL E REACH OF YANGTZERIVERFlood,a kind of interface disaster,occurs atthe interfacebetween atmosphere and lithosphere. Flood happens when at-mosphere and lithosphere interplay and couple each other(ofcourse,biosphere may also join in this) . Both meteorologicaland geographical factors can bring about flood;the formercontrols the time of flood and the latter controls the place ofdisaster. The second Neocathaysian tectonic subsidence area(L i,1973) is the…     

红崖山水库径流量减少与民勤绿洲水资源危机分析

民勤绿洲是武威、金昌等重要经济区的生态屏障。近半个世纪以来,随着石羊河中游工农业经济的持续发展,用水量不断增加,致使红崖山水库入库径流量不断减少,进而引起了下游民勤绿洲一系列生态环境问题,已到了"崩溃"的边缘。本文在定量分析入库径流量减少原因的基础上,全面阐述了民勤绿洲生态环境恶化的严重程度,并以流域水资源承载能力为依据,提出了解决民勤绿洲水资源危机之途径。     

压密注浆在既有房屋地基加固中的应用与实践

本文结合作者从事的压密注浆加固软土地基的设计及检测的工程.叙述了压密注浆的加固原理、加固效果;影响加固效果的各种因素、适用范围等,并例举了二个项目成功加固案例,同时指出了压密注浆在建筑工程上其它方面的应用前景。     

滨海工业入海排污口选址研究——以湛江钢铁项目为例

滨海工业入海排污口位置的合理选择对于减轻陆源排污对海洋环境污染有很重要的作用.本文以湛江钢铁项目为例,从海洋功能区要求、海洋环境容量、环境保护目标和扩散条件等因素考虑,对滨海工业入海排污口的选址进行了多方案的比选研究.通过比选研究结果,推荐符合当地海洋功能区划、远离主要环境保护目标、离岸深海排放(10m)、环境容量较大...     

Approximate general solution of 2-degrees of freedom dynamical systems using `les solutions precieuses'

This paper presents the procedure of a computational scheme leading to approximate general solution of the axi-symmetric,2-degrees of freedom dynamical systems. Also the results of application of this scheme in two such systems of the non-linear double oscillator with third and fifth order potentials in position variables. Their approximate general solution is constructed by computing a dense set of families of periodic solutions and their presentation is made through plots of initial conditions. The accuracy of the approximate general solution is defined by two error parameters, one giving a measure of the accuracy of the integration and calculation of periodic solutions procedure, and the second the density in the initial conditions space of the periodic solutions calculated. Due to the need to compute families of periodic solutions of large periods the numerical integrations were carried out using the eighth order, variable step, R-K algorithm, which secured for almost all results presented here conservation of the energy constant between 10^-9 and 10^-12 for single runs of any and all solutions. The accuracy of the approximate general solution is controlled by increasing the number of family curves and also by `zooming' into parts of the space of initial conditions. All families of periodic solutions were checked for their stability. The computation of such families within areas of `deterministic chaos' did not encounter any difficulty other than poorer precision. Furthermore, on the basis of the stability study of the computed families, the boundaries of areas of `order' and `chaos' were approximately defined. On the basis of these results it is concluded that investigations in thePoincaré sections have to disclose 3 distinct types of areas of `order' and 2 distinct types of areas of `chaos'. Verification of the `order'/`chaos' boundary calculation was made by working out several Poincaré surfaces of sections. This revised version was published online in July 2006 with corrections to the Cover Date.     

Numerical Investigation of the Galactic Problem by Computing Families of Periodic Solutions

The galactic dynamical system expressed by a third-order axisymmetric polynomial potential is investigated numerically by computing periodic solutions. We define as Sthe compact set of initial conditions generating bounded motions, and as S ^p , with S ^p ? S, the countable set of all initial conditions generating periodic solutions. Then, we consider the subsets S _s ^p and S _a ^p of S ^p , where S _s ^p ∪ S _a ^p = S ^p , S _s ^p S _a ^p = Ø, the first of which corresponds to symmetric periodic solutions, and the second to asymmetric solutions. Then, we approximate the set S _s ^p , leaving treatment of the set S _a ^p of asymmetric solutions for a future publication. The set S _s ^p is known to be dense in S (‘Last Geometric Theorem of Poincar;’, Birkhoff, 1913). Using a computer programme capable to locate all elements of the set S _s ^p that generate symmetric periodic solutions that re-enter after intersecting the axis of symmetry from 1 to ntimes. The results of the approximation of S _s ^p in the total domain and in the sample sub-domains of zooming, we present in graphical form as family curves in the (x, C) plane. The solutions located with the largest periods re-enter after 440 galaxy revolutions while the families calculated fully (initial conditions, period, energy, stability co-efficient) include solutions that re-enter after 340 galaxy revolutions. To advance further the approximation of the set S _s ^p thus obtained, we applied the same procedure inside eight sub-domains of the domain Sinto which we ‘zoomed’ through selection of finer search steps and double maximum periods. The family curves thus calculated presented in the (x, C) plane do not intersect anywhere in some sub-domains and their pattern resembles that of laminar flow. In other sub-domains, however, we found family curves from which branching families emanate. The concepts of completeand non-completeapproximation of S _s ^p in sub-domains of laminar and sub-domains with branching family curves, respectively, is introduced. Also, the concept of basic family of order1, 2, ..., n, are defined. The morphology of individual periodic solutions of all families is investigated, and the types of envelopes found are described. The approximate set S _s ^p was also checked by computing Poincar; sections for energy values corresponding to the mean energy range of the eight sub-domains of zooming mentioned above. These sections show that most parts of the compact domain in Sgenerating non-periodic but bounded solutions correspond to with well-shaped tori that intersect the x-axis, a fact that implies that dominant to exclusive type of periodic solutions are the symmetric ones with two normal crossings of this axis. The presence of non-symmetric periodic solutions as well as of chaotic regions is encountered. All calculations reported here were performed using the variable step R-K 8th-order direct integration and setting the allowable energy variation Δ C= |C _start? C _end| < 10^?13. The output, consisting of many thousands of families and their properties (initial conditions, morphology, stability, etc.), is stored in a directory entitled ‘Atlas of the Symmetric Periodic Solution of the Galactic Motion Problem’.