ANALYSIS MODEL ON GRADUAL CHANGE PRINCIPLE OF EFFECT ZONES OF LAYER FACE FOR ROLLED CONTROL CONCRETE DAM

The effect zones of layer face for RCC （rolled control concrete） dam have gradual change characteristics. Based on the analysis thought of complex material, a model was built to analyze above principle of RCC dam by use of series-wound and shunt-wound connection. Some methods were proposed to determine the instantaneous Young＇s modulus, delayed Young＇s modulus and viscosity coefficient of effect zones of layer face. Above models and methods were used to mine the principle of gradual change of key calculation parameters which can response the characteristics of effect zones. The principle of gradual change was described. A model was established to analyze the threedimensional viscoelastic problem of RCC dam. Above programs were developed. The examples show that the proposed models and methods to determine the key calculation parameters of effect zones can reflect the status of RCC dam accurately.

Unraveling the Stray Current-Induced Interfacial Transition Zone(ITZ)Effect on Sulfate Corrosion in Concrete

The rail transit in sulfate-rich areas faces the combined effects of stray current and salt corrosion;however,the sulfate ion transport and concrete degradation mechanisms under such conditions are still unclear.To address this issue,novel sulfate transport and mesoscale splitting tests were designed,with a focus on considering the differences between the interfacial transition zone(ITZ)and cement matrix.Under the influence of stray current,the ITZ played a pivotal role in regulating the transport and mechanical failure processes of sulfate attack,while the tortuous and blocking effects of aggregates almost disappeared.This phenomenon was termed the“stray current-induced ITZ effect.”The experimental data revealed that the difference in sulfate ion transport attributed to the ITZ ranged from 1.90 to 2.31 times,while the difference in splitting strength ranged from 1.56 to 1.64 times.Through the real-time synchronization of splitting experiments and microsecond-responsive particle image velocimetry(PIV)technology,the mechanical properties were exposed to the consequences of the stray currentinduced ITZ effect.The number of splitting cracks in the concrete increased,rather than along the central axis,which was significantly different from the conditions without stray current and the ideal Brazilian disk test.Furthermore,a sulfate ion mass transfer model that incorporates reactivity and electrodiffusion was meticulously constructed.The embedded finite element calculation exhibited excellent agreement with the experimental results,indicating its reliability and accuracy.Additionally,the stress field was determined utilizing analytical methods,and the mechanism underlying crack propagation was successfully obtained.Compared to the cement matrix,a stray current led to more sulfates,more microstructure degradation,and greater increases in thickness and porosity in the ITZ,which was considered to be the essence of the stray current-induced ITZ effect.

Experiment on Adiabatic Film Cooling Effectiveness in Front Zone of Effusion Cooling Configuration

Experimental investigation is performed to investigate the cooling characteristics in the front zone of effusion configuration. Effects of blowing ratio,multi-hole arrangement mode,hole-to-hole pitch and jet orientation angle on the adiabatic film cooling effectiveness are concentrated on. The results show that the film layer displays an obvious"developing"feature in the front zone of effusion cooling scheme,for either the staggered or inline multi-hole arrangement. The varying gradient of the laterally-averaged adiabatic cooling effectiveness along the streamwise direction is greater for the staggered arrangement than that for the inline arrangement. The holes array arranged in staggered mode with small hole-tohole pitches is in favor of obtaining developed film coverage layer rapidly.

Influence of permeation effect on themicrofabric of the slip zone soils: A case study from the Huangtupolandslide

This study aims to investigate the correlation between the permeation effect and microfabric of the slip zone soils with Huangtupo landslide in the Three Gorges Reservoir as the study case. Based on the permeability test and scanning electron microscope(SEM) images analysis, the fractal theory and probability entropy are used to quantify the characteristics of the remodeling specimens. First, the relationships between initial moisture content(IMC) and microstructure of the soil(percentage of particle area(PPA), pore roundness(Rp)) before and after permeability test are summarized. Then, the fractal dimension of the soil(pore distribution(Dpd), pore size(Dps)) are analyzed under the permeation effect. Based on the probability entropy, the entropy of pore(Ep) is used to characterize the porosity orientation, and the rose diagrams are used to show the particle orientation under the permeation effect. Finally, the relationship between the microstructure of the soil and its mechanical property is discussed. Results show that under the permeation effect, the microstructure of the soil has undergone tremendous changes. A flat long pore channel is formed. The order of the pore arrangement is enhanced, and soil particles switch the long axis to parallel infiltration direction to reach a new steady state. It can be inferred that the strength of soil would be weakened if the fractal dimension of soil pore decreases under any external environment.

Delineation and Scale Effect of Precision Agriculture Management Zones Using Yield Monitor Data Over Four Years

In this study, precision agriculture management zones were delineated using yield data over four years from the combine harvester equipped with yield monitor and DGPS receiver. Relative yields measured during each year were interpolated to 4 m2 grid size using ordinary kriging. The resultant interpolated yield maps were averaged across years to create a map of the mean relative yield, which was then used for cluster analysis. The mean yield map of post-classification was processed by applying majority filtering with window sizes that were equivalent to the grid sizes of 12, 20, 28, 36, 44, 52 and 60 m. The scale effect of management zones was evaluated using relative variance reduction, test of significant differences of the means of yield zones, spatial fragmentation, and spatial agreement. The results showed that the post-classification majority filtering （PCMF） eliminated lots of isolated cells or patches caused by random variation while preserving yield means, high variance reduction, general yield patterns, and high spatial agreement. The zoned result can be used as yield goal map for preplant or in-season fertilizer recommendation in precision agriculture.

Implementation Effect of Farmland Protection in Urumqi-Changji Economic Zone,China

A multi-level evaluation index system is established with farmland protection as the target layer,farmland quantity,farmland quality andfarmland sustainable development as the criterion layer.And the index layer includes the quantity change of farmland,per capita farmland area,multiple cropping index,total grain yield,unit grain yield,per capita grain security coefficient,and unit machinery dynamical input.Both expert eval-uation method and factor analysis method are used to determine the weight of index.According to the data in farmland area,grain yield and eco-nomic development in Urumqi-Changji Economic Zone in the years 1996-2007,a comprehensive evaluation model of intensive farmland use inUrumqi-Changji Economic Zone is established after data standardization.The overall implementation effect of farmland protection policy is ana-lyzed by integrating the farmland quantity,farmland quality and sustainable development.Result shows that implementation effect of farmland pro-tection shows an upward trend in general in Urumqi-Changji Economic Zone in the years 1996-2007,with a fluctuation in the years 2000-2003and a stable rising phase from 2004 till now.The maximum value is 0.779 in the year 2007;the minimum value is 0.242 in the year 1996;and themean value in the years 1996-2007 is 0.454.Farmland protection at first strictly controls the farmland quantity,then pays attention to farmlandquality,and finally focuses on the sustainable use of farmland.

Interaction between cracks and effect of microcrack zone on main crack tip

Mechanism interaction between cracks with different orientation angles is analyzed based on the principle of superposition and a flattening method. It is found that the maximum interaction effect does not occur when the microcrack is along the direction parallel or perpendicular to the principal tensile stress, which is different from the conclusion drawn by Ortiz （1987）. The mechanism of microcrack generation and the effect of the microcrack zone on the main crack tip are studied. It is concluded that the microcrack zone has effect on the main crack tip, which increases with the increase of microcrack density and length.

The effects of the intertropical convergence zone on the easterly jet stream during Northern summer

In this paper, a strong 1TCZ process and an 1TCZ - absent process during FGGE in 1979 were selected for comparison to explore how they were subject to the influence of the evolution of the upper easterly jets.

Determination of Effective Segregation Coefficient of Oxygen in Terbium During Floating Zone Refining

The effective segregation coefficient K-e of oxygen in terbium metal was deduced from a comparison of the theoretical curves with the concentration distributions found experimentally after a floating zone refining treatment. Thp result shows that K-e is equal to 1.2 which is an important parameter for floating zone refining terbium.

ECOLOGICAL LANDSCAPE EFFECTS OF WINDBREAK SYSTEMS IN DESERT ZONE OF WESTERN CHINA

This paper, by applying the theories of landscape ecology, illustrates the role and mechanism of windbreak system in the establishment and maintenance of oasis ecosystem on the basis of systematic analysis of characteristics and ecological crises of China's desert, and especially of desert zone in western China. Furthermore, direct economic benefits are summarized.

Mineralogy,M-type tetrad effect and radioactivity of altered granites at the G.Abu Garadi shear zone,central Eastern Desert,Egypt

The G. Abu Garadi area is covered mainly by metasediments, alkali feldspar granites and stream sediments. The alkali feldspar granite is traversed by a major strike-slip fault trending in an N-S direction as well as two subordinate sets of faults trending NW to WNW for the first one and NE for the second one. These faults represent the shear zones affected by magmatic (syngenetic) as well as hydrothermal (epigenetic) activities causing alteration of the granitic rocks. The most common alteration features are albitization, greisenization and koalinitization. The mass balance calculations of the studied altered samples show enrichments in Zr, Y, Ni, U, Th and Ga and depletions in Zn, Sr, Nb, Ba, Pb, Cu and V. Only the greisenized samples exhibit a significant enrichment in Nb, ∑REE budget and pronounced lanthanide tetrad effect (M-type), especially TE1,4, while weakly expressed tetrad effects are for the other albitized and koalinitized samples. Mineralogically, the common accessory minerals in the altered samples include samarskite-(Y), betafite, uranothorite, zircon, fluorite and cassiterite. The greisenized granites contain high eU and eTh than the other altered types, where they are characterized by an assemblage of the radioactive minerals; samarskite-(Y), betafite, uranothorite in addition to zircon. The inter-element relationships between U and Th and also their ratios illustrate that the radioelement distribution in these granites is mainly governed by magmatic processes, in addition to post-magmatic ones. The distribution of chemical elements and the fractionation of some isovalents within the shear zone are largely controlled by the newly formed mineral phases. With respect to uranium mobilization, uranium migrated from the host alkali feldspar granites of G. Abu Garadi, while the shear zones acted as traps for the migrated uranium. Moreover, U migrated in the shear zone during greisenization and albitization, and migrated out during koalinitization.

Possible effect of climate changes on the coastal zone of the Yangtze River Delta

A coastal historical evolution of the Yangtze River Delta was discussed in this paper on the basis of the historical data of the coastal zone and an estimation was made for the future change of the coast The emphasis was put on the future climate change that will have influence on the sea wall, coastal navigation and freshwater resources in the Delta It was also pointed out that the global warming and precipitation increase in the Yangtze River Valley may exert more impact on the zone In addition, some measures describing how to adapt to the climate change and reduce its impact were put forward

Spatial Variability of Microclimate Characteristics in Transition Zone of the Forest: A Case Study of Slătioara Secular Forest

Although the importance of forest margins in ecology is recognized, no study has been carried out in the Slătioara Secular Forest Reserve with reference to the variability of abiotic parameters along forest margins. With this study, we investigate to what extent microclimatic variables (air temperature—T_air, air humidity—H_air, soil temperature—T_soil, soil humidity—H_soil wind intensity (WIND) and photosynthetically active radiation intensity (PAR)) are correlated with the distance from the edge to the forest interior and the habitat type (forest interior, inner and outer edge and meadow) in the Slătioara Secular Forest Reserve. In order to measure these microenvironment variables we used the strip transect method, positioned perpendicular to the forest edge. Differences in the microenvironment variables considered in the analysis between the four habitat types were assessed using one-way ANOVA followed by Tukey-test post-hoc. To assess differences along transects, each of the six measurements went through a one-way ANOVA against distance to edge, followed by a Levene’s test for variances and finally a Tukey-test post-hoc. The results indicate that the values of microclimatic variables were significantly different in relation to the gradient of distance from the edge and to the habitat type (interior-exterior forest) and that edge habitats are significantly more susceptible to lower humidity, high winds, lower light and higher air temperatures than forest interior habitats. The ecological study of the edge areas in this reserve provides the basis for future research on forest dynamics and can guide conservation efforts to maintain the diversity and endemism of species in the Slătioara Secular Forest.

A STUDY OF ELECTROCHEMICAL BEHAVIOUR OF VARIOUS THERMAL HISTORY ZONES AND DIFFERENT PHASE STRUCTURES ON THE WELDMENT FOR LOW ALLOY STEEL 16Mn IN NITRAfE SOLUTION

The electrochemical behaviour, including free corrosion potential, free corrosion current density and polarization curve, of various thermal history zones on the weldment was measured in this paper. The weldment consisted of matrix, tempering zone. incomplete normalized zone, normalized zone, overtemperature zone, fusion line zone and weld metal zone. The electrochemical behaviour of the ferrite, pearlite and mixed structure in various zones have successfully measured. The results showed that there was a difference of free corrosion potential which is smaller than ca. 200mV between various zones and about 20-150mV potential difference between ferrite and pearlite in every zone. The free cormsion potential of fusion line zone was the most negative between various zones. The free corrosion potential of pearlite was some dozens mV more negative than ferrite. The corrosion course of various zones and of different phase structures on the weldment and their effect on corrosion attack of weldment were discussed.

Hydrocarbon migration and accumulation along the fault intersection zone-a case study on the reef-flat systems of the No.1 slope break zone in the Tazhong area, Tarim Basin

Understanding hydrocarbon migration and accumulation mechanisms is one of the key scientif ic problems that should be solved for effective hydrocarbon exploration in the superimposed basins developed in northwest China. The northwest striking No.1 slope break zone, which is a representative of superimposed basins in the Tarim Basin, can be divided into five parts due to the intersection of the northeast strike-slip faults. Controlled by the tectonic framework, the types and properties of reservoirs and the hydrocarbon compositions can also be divided into five parts from east to west. Anomalies of all the parameters were found on the fault intersection zone and weakened up-dip along the structural ridge away from it. Thus, it can be inferred that the intersection zone is the hydrocarbon charging position. This new conclusion differs greatly from the traditional viewpoint, which believes that the hydrocarbon migrates and accumulates along the whole plane of the No.1 slope break zone. The viewpoint is further supported by the evidence from the theory of main pathway systems, obvious improvement of the reservoir quality （2-3 orders of magnitude at the intersection zone） and the formation mechanisms of the fault intersection zone. Differential hydrocarbon migration and entrapment exists in and around the strike- slip faults. This is controlled by the internal structure of faults. It is concluded that the more complicated the fault structure is, the more significant the effects will be. If there is a deformation band, it will hinder the cross fault migration due to the common feature of two to four orders of magnitude reduction in permeability. Otherwise, hydrocarbons tend to accumulate in the up-dip structure under the control of buoyancy. Further research on the internal fault structure should be emphasized.

HEAT-AFFECTED ZONE FRACTURE TOUGHNESS OF HIGH STRENGTH STEELS EVALUATED USING THE WEAKEST LINK MODEL

A probabilistic model is derived based on the weakest link theory to evaluate the specimen thickness effect and the size effect of coarse-grained heat-affected zone (CGHAZ) on CTOD toughness values in heat-affected zones (HAZ) of high strength steels. The scatter of CTOD fracture toughness values in heterogeneous weldments is predicted using this model. The specimen thickness has influence on the CTOD toughness values of HAZ. With increase in the specimen thickness the estimated and experimental mean CTOD values decrease while the lower boundary CTOD values remain almost unchanged. The size of CGHAZ has strong negative effect on the mean CTOD values of HAZ. The estimated mean CTOD values and lower boundary CTOD values agree with experimental CTOD testing results of HAZ notched specimens. The facture toughness scatter is dependent on the Weibull shape parameter a and specimen thickness.

深层-超深层致密储层天然裂缝分布特征及发育规律

天然裂缝是深层-超深层致密储层的有效储集空间和主要渗流通道,影响着致密储层油气的运移、富集、单井产能、开发方式及开发效果。通过对近年来致密储层裂缝研究成果总结和文献综述,分析了深层-超深层致密储层天然裂缝分布特征及发育规律。将致密储层天然裂缝分为大尺度裂缝、中尺度裂缝、小尺度裂缝和微尺度裂缝4个级别。不同尺度裂缝分布具有幂律分布的特点,裂缝尺度越大,数量越少;裂缝尺度越小,数量越多。大、中尺度裂缝主要起渗流作用,小尺度裂缝主要起渗流和储集作用,而微尺度裂缝主要起储集作用。在地层埋藏过程中的应力体制演化决定了不同时期天然裂缝的类型、产状及其力学性质;构造应力大小、岩石力学层的力学性质和厚度差异控制了多尺度裂缝的形成分布及其发育程度。构造变形导致不同构造部位的局部应力和应变分布产生差异,增强了裂缝发育的非均质性。逆冲断层通过控制其上盘地层变形控制了“裂缝域”的分布规律;走滑断层的组合样式、活动方式和岩石力学层共同控制了相关裂缝的三维空间展布。裂缝形成演化过程中的开启-闭合规律决定了裂缝的储集空间,记录了裂缝有效性的演化历史。

考虑采动效应的闭坑矿井水硫酸盐污染规律

高硫煤矿闭坑后成为埋藏在地表以下深部的产酸污染场,对相邻含水层和周边环境造成了潜在危害,且因采动效应影响和矿井空间分布复杂导致相邻含水层的污染过程与污染程度评价困难。以某闭坑矿区为研究对象,选取SO_(4)^(2-)作为特征污染物,考虑多煤层采动裂隙对含水层结构的破坏影响,运用数值模拟技术对闭坑矿区酸性矿井水中SO_(4)^(2-)污染迁移特征进行研究,并分析流体扩散系数对含水层污染物运移的影响。结果表明:SO_(4)^(2-)在二叠系童子岩组砂岩含水层中水平迁移面积随时间增大而增大,增大速率逐渐减小,垂向渗透系数扩大10倍,空间变异性增强;闭坑5、10、15a后,最大水平迁移距离分别为215、414、612m,最大垂向迁移距离分别达到50、65、70m;而扩散系数越大,产酸时间越长,SO_(4)^(2-)迁移距离和污染范围将随之增大,相较于水平方向,垂向上SO_(4)^(2-)浓度变化对扩散系数的敏感度更高。基于模拟结果,结合闭坑矿区实际条件,针对性提出了“源头减量-过程阻断-末端治理”的综合防控与治理方案。研究结果将为该闭坑煤矿酸性矿井水污染治理与防控提供理论基础,也为其他同类矿井提供科学借鉴。

Research on Two Types of Buffer Zone Impact on Surrounding Office Space Environment in Winter in Cold Climate Zone—a Fieldwork in Architectural Design Institute Building of Tsinghua University,Beijing

Building buffer zone space is not only one of essential approaches for better mental quality of interior building space, but also an important factor that may influence interior thermal comfort and energy consumption. This study aims to analyze regulative advantages of buffer zone to the surrounding functional spaces. Based on a fieldwork test in a typical office building in cold climate zone in Beijing,China,the monitor data show interior physical performance in the Winter. The research selects two types of different buffer zones in the same building. One is a south-faced greenhouse which has large dimension with plenty of vegetation,and the other is a simple atrium in the middle of five floor building with mount of skylights. The factors and their influence to surrounding functional spaces and the whole building are found out from the comparisons of collected data by floor to floor monitor test on both buffer zones at the same time. The comparisons of two types of buffer zones conclude that the greenhouse is more effective to air quality regulation but not so clearly wellperformed to thermal buffering as expected due to the dominate active central heating in the Winter. This fieldwork test results for building performance can be helpful for both architects and engineers in the early phase of sustainable design.