北京交通拥堵的外部性及其政府解决方法初探

本文针对北京市日益严重的交通拥堵及由此引起的大气污染和安全问题, 结合环境经济 学的外部性理论, 提出应该重视汽车交通的外部性, 认为北京市的交通拥堵症结在于外部性引起 的市场失效。由于汽车交通的群体性特点, 应该使用政府方法来解决城市汽车交通的外部性, 文 章结合英国伦敦市、新加坡和日本名古屋市的交通管理措施, 建议采取管制和经济手段相结合的 方式, 从控制机动车拥有量和机动车出行率及鼓励市民采取公共交通方式出行等各个方面加强 对北京市交通的管理。     

对矿物包裹体溶液性质的新认识——兼论含矿溶液是酸性溶液的地质证据

对金属矿床成矿溶液的性质 ,特别是 pH值 (酸碱度 )的确定 ,是认识含矿溶液的成因、成矿条件和成矿机理的关键。目前对成矿溶液性质的研究主要局限在对围岩蚀变矿物包裹体的测定方面 ,并得出近中性热卤水成矿的结论。作者认为 ,多数围岩蚀变矿物的包裹体溶液不能代表原成矿溶液的性质 ,“近中性的热卤水成矿”的认识有误 ,应是酸性水形成的含矿溶液成矿 ,并从矿物包裹体溶液的特征、Roedder的高金属含量的矿物包裹体溶液的发现、氢氧同位素资料、矿物包裹体中高卤水溶液的起源以及成矿溶液的演化机理等方面论述了酸性金属含矿溶液的成因及成矿演化过程。     

Wind-driven, double-gyre, ocean circulation in a reduced-gravity, 2.5-layer, lattice boltzmann model

A coupled lattice Boltzmann （LB） model with second-order accuracy is applied to the reduced-gravity, shallow water, 2.5-layer model for wind-driven double-gyre ocean circulation. By introducing the secondorder integral approximation for the collision operator, the model becomes fully explicit. The Coriolis force and other external forces are included in the model with second-order accuracy, which is consistent with the discretization accuracy of the LB equation. The feature of the multiple equilibria solutions is found in the numerical experiments under different Reynolds numbers based on this LB scheme. With the Reynolds number increasing from 3000 to 4000, the solution of this model is destabilized from the anti-symmetric double-gyre solution to the subtropic gyre solution and then to the subpolar gyre solution. The transitions between these equilibria states are also found in some parameter ranges. The time-dependent variability of the circulation based on this LB simulation is also discussed for varying viscosity regimes. The flow of this model exhibits oscillations with different timescales varying from subannual to interannual. The corresponding statistical oscillation modes are obtained by spectral analysis. By analyzing the spatiotemporal structures of these modes, it is found that the subannual oscillation with a 9-month period originates from the barotropic Rossby basin mode, and the interarmual oscillations with periods ranging from 1.5 years to 4.6 years originate from the recirculation gyre modes, which include the barotropic and the baroclinic recirculation gyre modes.     

考虑土体结构性损伤的沉桩挤土效应解析分析

根据土塑性力学基本原理,采用简化的线性软化模型并考虑土的结构性损伤影响,推导出沉桩时产生的挤压应力的空间解析解,并在此基础上分析了土体具有不同的损伤程度时沉桩产生的挤压应力和极限扩张压力的空间分布规律。同时,采用Henkel孔隙水压力公式,进一步分析孔隙水压力的发展规律,该解析解可以弥补经典圆孔扩张理论在沉桩应用中的不足,能更好地揭示沉桩时的挤土机理。     

三种猪毛菜种子耐盐性与幼苗干燥存活能力

在控制条件下研究了三种藜科植物紫翅猪毛菜(Salsola affinisC.A.Mey.)、浆果猪毛菜(Salsola foliosa(L.)Schrad.)和钠猪毛菜(Salsola nitrariaPall.)种子的萌发特性以及萌发后的幼苗在室温中放置14天和30天之后重新放置在原溶液中的存活状况。结果表明:三种猪毛菜种子在无菌水、0.085 mol/L、0.17 mol/L、0.34 mol/L NaCl溶液中萌发的很好,但是在0.51 mol/LNaCl中萌发率很低,三种猪毛菜幼苗在干燥30天重新放置在原溶液中以后仍然具有很高的存活率。上述结果表明:已经萌发了的幼苗在干燥环境中仍然保持存活的能力是盐生植物为了适应极端干旱和盐渍荒漠环境的一个重要的生存策略。     

2016年安徽无为MS3.0震群序列发震构造与震后趋势研究

首先通过模板匹配方法检测无为震群活动期间目录遗漏的地震事件,共识别出5次遗漏地震事件,震级为M_L0.5～1.2,得到了更为完整的地震目录;然后基于波形互相关震相检测技术标定震相到时,进而采用双差定位方法进行精定位,精定位后震群分布更加集中,未见明显的优势方位分布;采用Snoke方法计算震级较大地震的震源机制,结果表明,此次震群为NEE向的水平挤压与NNE向的水平拉张应力场作用下具逆冲分量的走滑型地震活动,严家桥-枫沙湖断裂可能为其发震构造;最后,计算了震群序列的视应力,结果显示,视应力和扣除震级影响后的差视应力随着震群序列的衰减逐渐恢复,因此,分析认为,随着无为震群序列的衰减,震源区发生更大地震的可能性不大。     

The Cosmological Scalar in the Jordan-Brans-Dicke Theory. II.

Cosmological solutions are examined in the proper representation of the JBD theory with a dominant nonminimally coupled scalar field. It is shown that only the introduction of a cosmological scalar that transforms to the ordinary cosmological constant in the Einstein representation enables a phase of evolution with a uniform and then an accelerated expansion of the universe over cosmological time scales. __________ Translated from Astrofizika, Vol. 48, No. 4, pp. 633–640 (November 2005).     

The equilibrium configurations of the restricted problem of 2+2 triaxial rigid bodies

The restricted 2+2 body problem is considered. The infinitesimal masses are replaced by triaxial rigid bodies and the equations of motion are derived in Lagrange form. Subsequently, the equilibrium solutions for the rotational and translational motion of the bodies are detected. These solutions are conveniently classified in groups according to the several combinations which are possible between the translational equilibria and the constant orientations of the bodies.     

An improved method for delineating source protection zones for karst springs based on analysis of recession curve data

A standard method for delineating source protection zones, particularly for karst and carbonate springs, has been improved. The method, based on recession curve analysis, defines four vulnerability scenarios with an evaluation of the appropriate dimensions of the protection areas, accommodating situations where field-test data are not available. The new approach makes it easier to separate the components of the spring discharge hydrograph. The objective is to achieve simplification, and an effective, more rigorous, procedure in the determination of the parameters used by Mangin’s model—Mangin A (1975) Contribution a l’étude hydrodynamique des aquifères karstiques-Troisieme partie: Constitution et fonctionnement des aquifères karstiques (Contribution to the hydrodynamic study of karst aquifers, part 3: formation and work of karst aquifers). Ann Speleol 30(1):21–124. The original procedure, plus the lack of sufficient data, was open to subjective interpretation. With the aid of modern technology, a very large quantity of data is now available and it is necessary to process it using denoise type computer-based filters before passing to interpretation. Working with discharge data series, a statistical approach is proposed to give an analytical solution for determining the values of fundamental parameters of the recession curve model. The new procedure is defined and compared with the original methodology. The new approach has been tested and applied to a number of karst springs in Italy. A case history for a spring located in the Piedmont region of the Maritime Alps, is presented. The proposed new procedure can be utilised to mark the limits of the protection zones of tapped groundwater supplied for potable use, as required by European and local legislation.