土地整理项目生态环境影响评价——以富顺县怀德镇土地整理项目为例

论文以富顺县怀德镇司湾村、界牌村、坝中村土地整理项目为例,对土地整理项目主要工程对生态环境的影响进行了深入研究并加以归纳概括,构建了土地整理生态环境影响评价指标体系与评价模型。经评价,整理前项目区生态环境综合指数为0.797,整理后为1.164,提高46%,说明经过土地整理,该区生态环境大大改善,从而证明该土地整理项目是科学的、可行的。     

后评价方法在土地整理项目效益后评价上的应用

从项目后评价方法的特点出发，探讨了项目后评价方法在土地整理项目效益后评价上的应用，侧重分析了前后对比法、有无对比法、成功度法和模糊综合评判法4种方法的应用方法和应用特点，对指导我国土地整理项目后评价的理论研究和实践开展具有一定的意义。     

太谷县乌马河土地开发整理项目的后评价报告

通过详实的数据,从增加耕地数量、提高耕地生产能力、改善农民生产生活条件及生态环境等方面对土地开发整理项目工作的成效进行了系统评价和宣传。通过评价,我们发现进行土地开发整理项目实现了社会、生态、经济三大效益,促进整理事业可持续发展,宣传土地开发整理工作和增强土地开发整理事业生命力。     

商河县郑路镇中低产田项目治理综合效益分析

土地整理效益研究是土地整理理论及实践研究的重要组成部分,也是当今土地科学领域专家和学者关注的重要课题。结合商河县郑路镇项目区的自然和社会经济条件以及土地利用状况,对土地开发整理项目进行社会效益、生态效益及经济效益分析,指出土地整理应寻求社会、生态和经济三大效益的最大结合,实现效益最大化,最终促进农村经济的可持续发展。     

黄河三角洲盐渍土区土地整理实施及绩效评价

该文以垦利县永安镇五村片省级土地整理项目为例,在对土地整理规划设计、实施管理和效益评价的基础上,提出了黄河三角洲盐渍土区土地整理项目绩效评价的重点内容、主要指标和基本思路,对于丰富黄河三角洲盐渍土区土地整理理论,规范和指导黄河三角洲盐渍土区土地整理实践具有重要的指导和现实意义。     

区域建设用地节约集约利用评价研究——以三亚市为例

为促进区域土地资源的优化配置和合理利用,提高土地集约节约利用,本文结合研究区域的社会经济、土地利用等的实况,采用特尔斐法、定性分析与综合评价法开展研究。结果表明:三亚市建设用地基本还处在粗放向集约过度的阶段,全市集约利用值为62.763,节约集约利用水平不高,且地区差异显著,天涯区的集约利用值分别是崖州区和海棠区约1.5倍。三亚市的实证研究结果表明,本文所构建的综合评价法及其评价指标体系具有一定可行性和较强操作性,对其他区域土地集约节约利用评价具有参考价值。针对三亚市土地利用存在的问题,从建立健全土地交易市场、调整土地利用结构、建立区域建设用地节约集约利用的考核标准及奖惩制度、增强民众土地集约利用意识等方面提出了政策建议。     

基于综合评价的日照市农用地整理时序研究

通过探讨农用地整理的时序,为规范土地整治管理提供技术支撑。运用综合评价法、实证分析法,选取自然经济社会条件、耕地利用现状和农用地整理3个因素、6个评价因子,构建农用地整理评价指标体系。以山东省日照市为例,进行实证分析,确定49个乡镇农用地整理时序。得出通过综合评价确定农用地整理时序,能够使农用地整理管理更加科学化和规范化。     

富硒耕地质量评价体系构建及其在湖南省新田县新圩镇的应用

【研究目的】天然富硒农产品是人体摄入硒元素最安全有效的途径,依托天然富硒土地资源建立的富硒农业和富硒特色小镇等富硒产业,成为脱贫攻坚和乡村振兴的新兴产业支柱,其规划和建设需以富硒土地质量等级为基础,但国内缺乏富硒土地资源评价体系。【研究方法】本文以新田县为例,从耕地的开发利用条件和潜力、开发利用价值以及开发制约条件着手,构建耕地地力、经济质量和生态环境“三位一体”的富硒耕地质量评价体系;基于新田县新圩镇富硒土壤详查数据和全国土地调查成果开展富硒耕地质量评价研究,对耕地的自然属性、环境属性、经济属性等进行综合评价。【研究结果】其评价结果与农产品质量和富硒程度耦合良好,真实反映了耕地资源开发条件与潜力。【结论】构建的富硒耕地质量评价体系对富硒耕地资源开发利用有较科学指导价值,为富硒土地资源和富硒产业规划提供了重要参考和借鉴。创新点：从耕地的开发利用条件和潜力、开发利用价值和制约条件着手,构建耕地地力、经济质量和生态环境“三位一体”的富硒耕地质量评价体系,制定指标权重、调查评价单元、单因子等级和综合等别划定等方法与规则。     

丘陵山地农村公路水毁灾害成因分析与风险评价——以泉州市德化县农村公路为例

针对闽东南丘陵山地农村公路水毁灾害成因分析以及风险定量评价的问题,本文对风险评价体系进行了论述。以福建省泉州市德化县农村公路作为研究区,将农村公路水毁按照承灾体划分为5个类型,并对各类型的水毁成因进行关联系分析,得出农村公路水毁是一个综合的系统。通过对研究区内水毁灾害点的分析,将农村公路水毁风险划分为4个等级,选取降雨量、降雨强度、降雨历时、边坡土质等10个评价因子,利用层次分析法计算每个评价因子的权重,结合专家和工程技术人员对评价因子的打分值,计算得到德化农村公路典型水毁灾害点各风险等级的易发值,进而判断该点的水毁风险等级,评价结果与现场调查相符合。结果表明:层次分析法在农村公路水毁风险评价中的应用效果良好,该评价体系为闽东南丘陵山地类似的农村公路水毁风险定量评价提供了理论依据。     

惠民县两个土地整理项目顺利通过省级验收

8月25日,惠民县国家重点投资土地整理项目——何坊乡等土地整理项目和省重点投资土地整理项目——惠民镇省屯土地整理项目顺利通过省级土地开发整理项目验收组的考核验收,并被省验收组评价为全省为数不多的好项目之一。2个土地整理项目总投资4859万元,建设总规模2386．8hm2,新增耕地329．67hm2,新增加耕地率为16．5％。     

Physical properties of a horizon of a white hole and a Kruskal wormhole

The possible application of a Rindler type reference frame for studies of physical processes near the horizons of black and white holes is considered. New similar reference frames inside black and white holes in the region T of a Kruskal wormhole are introduced.     

Gamma-ray bursts as a result of the interaction of a shock from a supernova and a neutron-star companion

A supernova explosion in a close binary system in which one of the components is a compact magnetized object (neutron star or white dwarf) can form a narrow “tail” with length l _t ～10⁹ cm, width h _t ～10⁸ cm, and magnetic field B _t ～10⁶, due to the resulting shock wave flowing around the magnetosphere of the compact object. The energy released by the reconnection of magnetic field lines in this tail can accelerate electrons to relativistic speeds (γ≈10⁴), creating the conditions required for powerful synchrotron radiation at energies from hundreds of keV to several MeV, i.e., for a gamma-ray burst (GRB). The duration of this radiation will depend on the power of the shock that forms during the supernova. If the shock is not sufficiently powerful to tear off the magnetosphere tail from the compact object, the duration of the GRB will not exceed l _t /V _A ≤1 s, and the conditions necessary for an “afterglow” at softer energies will not arise. If the shock is more powerful, the tail can be torn from the magnetosphere, forming a narrow ejection, which is perceived in its relativistic motion toward the observer(Γ～10⁴) as an afterglow whose duration grows from tens of seconds at gamma-ray energies to tens of days in the optical. This may explain why afterglows are observed only in association with long GRBs (T ₉₀>10 s). Very short GRBs (T ₉₀<0.1 s) may be local, i.e., low-power, phenomena occurring in close pairs containing compact, magnetized objects, in which there is again an interaction between the magnetosphere of the compact object and a shock wave, but the shock is initiated by a flare on the companion, which is a red-dwarf cataclysmic variable, rather than by a supernova.     

Coupled consolidation of a porous medium with a cylindrical or a spherical cavity

This paper presents a theoretical approach to analyse coupled, linear thermoporoelastic fields in a saturated porous medium under radial and spherical symmetry. The governing equations account for compressibility and thermal expansion of constituents, heat sink due to thermal dilatation of water and thermal expansion of the medium, and thermodynamically coupled heat–water flow. It has been reported in the literature that thermodynamically coupled heat–water flows known as thermo-osmosis and thermal filtration have the potential to significantly alter the flow fields in clay-rich barriers in the near field of a underground waste containment scheme. This study presents a mathematical model and examines the effects of thermo-osmosis and thermal-filtration on coupled consolidation fields in a porous medium with a cavity. Analytical solutions of the governing equations are presented in the Laplace transform space. A numerical inversion scheme is used to obtain the time-domain solutions for a cylindrical cavity in a homogeneous or a non-homogeneous medium. A closed form time-domain solution is presented for a spherical cavity in a homogeneous medium. Selected numerical solutions for homogeneous and non-homogeneous media show a significant increase in pore pressure and displacements due to the presence of thermodynamically coupled flows and a negligible influence on temperature. © 1998 John Wiley & Sons, Ltd.     

Phase space of a two-dimensional model of a Parker dynamo

The dependences of the magnetic-field strength, variations of the magnetic field, and the multipole level on the amplitudes of the α and ω effects are considered using a two-dimensional model for a Parker dynamo in a spherical layer. Calculations have been carried out for both traditional spatial distributions of α and ω and geostrophic regimes obtained from three-dimensional modeling of thermal convection. Two-dimensional distributions of the dynamo-wave velocities in the zone where magnetic field is generated are presented. Comparisons with the solar and planetary dynamos are considered.     

Propagation of a shear crack in a compressed plane with a circular hole

The problem of the equilibrium of a plane with a circular hole and a shear crack is considered to model failure of an excavation (borehole or circular opening) in rocks weakened by discontinuities (planes of weakness). It is assumed that sliding occurs in a part of the plane of weakness when the Mohr–Coulomb friction criterion is satisfied due to the stress redistribution caused by the excavation. The method of singular integral equations is employed to solve the boundary value problem. Geomechanical problems concerning borehole breakout and rockburst caused by fault-opening interaction are discussed. © 1998 John Wiley & Sons, Ltd.     

Scattering of a plane wave by a lined cylindrical cavity in a poroelastic half-plane

The focus of this contribution is to develop a complex variable function method to solve the two-dimensional scattering of plane waves by a lined cylindrical cavity in the poroelastic half-plane. The poroelastic half-plane is based on Biot’s dynamic theory, and the governing equations are solved by reduction to three Helmholtz equations. The lining structure can be treated as an elastic material and decoupled into two Helmholtz equations. Here, the large circle assumption is applied to simulate the half-plane boundary. By using appropriate boundary conditions and continuity conditions, the unknown coefficients in the potentials can be determined. Selected numerical results are presented in this paper.     

Spreading of a NAPL lens in a double-porosity medium

Spreading of a non-aqueous phase liquid (NAPL) denser than water (DNAPL) lens (mound) in the unsaturated zone of double-porosity aquifer above an impervious plane boundary is investigated. The double-porosity aquifer is conceptualized as a fracture network surrounding pervious blocks. Vertical gravity equilibrium is assumed to prevail in each one of the two media, fractures and blocks. Through vertical integration, two coupled partial differential equations for the DNAPL content in each medium are obtained. The mass exchange rate between high- and low-permeability media is considered as a function of NAPL content. The dominant effect is gravity, whereas capillary forces are negligible. Analytical solutions for one-dimensional and axisymmetric problems of mound spreading are obtained.     

Toward a definition of a mineral sample in geology

Summary Any rock may be regarded as an aggregate of mineral species frequency distributions, thus opening up a new method of analyzing the problems of the nature of these discrete distributions.Based on theorems in mathematical probability, a subrock sample is defined as a probability sample under the conditions that every mineral species' distribution function in this subrock converges probabilistically to one and the same distributions the nature of which is immaterial at this point.For obvious reasons, the situation is excluded if the sample size approaches infinity, i.e., Chebyshev's theorem (Chebyshev, 1867).     

Strain analysis of a shear zone in a granodiorite

A ductile shear zone in a late Precambrian granodiorite, from the Rouergue (southwest part of the French Massif Central) has been studied.A single episode of deformation is responsible for the formation of a foliation and a well-defined lineation which are localized into an elongated zone, a few decimeters wide.The strain features can be attributed to a simple-shear mechanism (Ramsay and Graham, 1970), so that the main parameters of the deformation are defined.At stages of increasing deformation, the quartz isotropic sub-fabric of the undeformed host rock is progressively transformed into an anisotropic fabric composed of a single oblique girdle while the subgrain size progressively decrease and the dislocation density remains constant. It is suggested that the gliding planes of quartz are the basal plane (0001) and a predominant prismatic plane 101&#x0304;0 the slip directions may be a for both glide-planes.The results obtained in this investigation provide a basis for a high voltage electron microscope (H.V.E.M.) study which shows that the fabrics development may be related to dislocation processes. The difference of strain rates in the host rock and in the shear zone is calculated from the dislocation microstructures.