丹江口大坝加高工程左岸贴坡混凝土施工

南水北调中线丹江口大坝加高工程是目前国内最大的水利枢纽改扩建工程,技术复杂、施工难度大、工艺要求高。通过制定合理的贴坡混凝土施工方案、科学的施工工序及合理的资源配置,采用先进的施工技术,在确保枢纽安全运行的前提下,保证了左岸贴坡混凝土施工按节点工期顺利完成。

Hot deformation behavior and workability of pre-extruded ZK60A magnesium alloy

The hot deformation behavior and workability of pre-extruded ZK60A magnesium alloy were investigated by compression tests in the temperature range of 250-450 ℃and the strain rate range of 0.001-10 s 1. The constitutive equation for the pre-extruded ZK60A alloy can be described by hyperbolic sine function. Processing maps were constructed from true strains of -0.2 to -0.8. The alloy experienced complete dynamic recrystallization （DRX） and showed good workability in the temperature range of 300-400 ℃ and the strain rate range of 0.01-0.001 s-Z, where hot working in pre-extruded ZK60A, such as forging, can be carried out. For large deformation to true strain of over -0.5, strain rates above 0.1 s-1 are not recommended at all temperatures, where flow instability such as local strain concentration, twinning deformation, abnormal grain growth, micro-cracks, and shear fracture were observed. Climb-controlled dislocation creep dominates both the plastic deformation and nucleation of DRX of the pre-extruded ZK60A magnesium alloy.

Coefficients of earth pressure at rest in thick and deep soils

The effect of test methods and stress paths on the experimental value of the coefficient of earth pressure at rest, K0, was investigated under high pressures. The results indicate that the rigid pressure chamber and flexible lateral confining pressure medium method gives a stress ratio at the initial stage that is not the real K0. Moreover, K0 increases during the loading process becoming greater at high pressures. In the unloading process, however, K0 increases only at the initial stage but decreases thereafter. In addition, the incremental magnitude definition, K0=dσ3/dσ1, gives higher values than the total magnitude definition, K0=σ3/σ1, under loading. This is also true during initial stages of unloading. The experiment results also indicate that earth pressure at rest in deep and thick soils can be estimated by a power function of axial and confining pressures. It is necessary to choose the appropriate Kn to avoid some accidents.

Global lateral buckling analysis of idealized subsea pipelines

In order to avoid the curing effects of paraffin on the transport process and reduce the transport difficulty,usually high temperature and high pressure are used in the transportation of oil and gas.The differences of temperature and pressure cause additional stress along the pipeline,due to the constraint of the foundation soil,the additional stress can not release freely,when the additional stress is large enough to motivate the submarine pipelines buckle.In this work,the energy method is introduced to deduce the analytical solution which is suitable for the global buckling modes of idealized subsea pipeline and analyze the relationship between the critical buckling temperature,buckling length and amplitude under different high-order global lateral buckling modes.To obtain a consistent formulation of the problem,the principles of virtual displacements and the variation calculus for variable matching points are applied.The finite element method based on elasto-plastic theory is used to simulate the lateral global buckling of the pipelines under high temperature and pressure.The factors influencing the lateral buckling of pipelines are further studied.Based upon some actual engineering projects,the finite element results are compared with the analytical ones,and then the influence of thermal stress,the section rigidity of pipeline,the soil properties and the trigging force to the high order lateral buckling are discussed.The method of applying the small trigging force on pipeline is reliable in global buckling numerical analysis.In practice,increasing the section rigidity of a pipeline is an effective measure to improve the ability to resist the global buckling.

Changes in Texture, Structure and Pectin of Peach during Pressurization, Heating or Processing of High-pressure-induced and Heat-induced Jam

The objectives of this study are to research the relationship between pectin and the softening of peach by soaking in citric acid solutions for 24 h at 35 ℃, pressurizing for 30 rain at 500 MPa or heating for 10 min. Also, comparing high-pressure-induced jam （HP-jam） and heat-induced jam （H-jam） were evaluated. It was found that firmness of the peach decreased greatly when soaked at pH 2.0 〉 heated 〉 soaked at pH 2.2 or 2.5 〉 pressurized, respectively. About 88% of the peach pectin was water-soluble-pectin and high-methoxyl pectin, while low-methoxyl pectin was slight. During pressurization, the pectin did not change. However, pectin degraded through hydrolysis during heating; consequently, the middle lamella separated. Also, eight kinds of peach jam （65% sugar, pH 2.0 or pH 2.2, and 50% or 60% sugar, pH 2.5） were compared. Both color and flavor of HP-jam were better than H-jam. As the pH values were lower, L-, a-, b-values of jam became higher, and the jam became pinker. Raw peach contained about 0.3%-0.4% pectin, therefore, an addition of 0.6% pectin was needed for both HP- and H-jams. However, there was no great difference in rheology or sensory evaluation between HP- and H-jams.

Football Diplomacy

This research ＂Football Diplomacy＂ represents a political activity implemented in the Caucasian policy of Turkey in one special direction, in particular it addresses settlement of relations broken offwith the Republic of Armenia in the early 1990s. The author of the submitted political project is the President of Turkey, Abdullah Gul together with the Foreign Minister by that time-Ahmet Davutoglu. By his direct instruction, the Turkish diplomacy developed one more plan known under the name of ＂Football Diplomacy＂ by 2009. Despite the fact that high-rank officials of both countries were engaged in implementation of this plan and works necessary for consolidation of public opinion were carried out in both countries, the process was suspended anyway and principal changes have not occurred in bilateral relations until now.

Study on high rock slop anchoring technique of large rock engineering

Monitoring data from the Three Gorges Project show that the resulted tensile stresses are mainly distributed within the front section of the internal anchoring section which is often measuring 2.5 m in length. The composition of two early strength cement grout mixes marked as R_3350 and R_7350 was successfully developed to accelerate anchoring facilities installation and to reduce its intervention with the shiplock construction. It was measured that the ground water pH value in the sidewall slopes of the permanent navigation shiplock during the construction period was close to 8. Based on those characteristics it is concluded that the groundwater is weakly corrosive to steel material and will appear as non-corrosive to the steel wire strands embedded in the cement grout set. The advanced model of 3 MN unbonded anchor cables with double anti-corrosion protection(including the corrugated pipe) is developed to meet the needs of stabilizing the high sidewall rock slopes of the permanent navigation shiplock on the Three Gorges Project.

Equation of state of Zr_(41)Ti_(14)Cu_(12.5)Ni_(10)Be_(22.5) bulk metallic glass

The knowledge of the equation of state(EOS)and the compressibility of a solid are of central importance for the understanding of the behavior and the application of a condensed matter.The compression behavior of Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass(BMG)is investigated at room temperature up to 24 GPa using in-situ high pressure energy dispersive X-ray diffraction with synchrotron radiation.A model of basic cell volume has been established and the equation of state of BMG is determined by the calculation of radial distribution function.The experimental results indicate that the BMG contains a large amount of vacancy-like free volume.Low pressure(below 7 GPa)induces the collapse of the free volume to some extent and structure relaxation in the BMG.

The application study of polycarboxylates water-reducing admixture in passenger dedicated line engineering

Polycarboxylate water-reducing admixture possesses the capability which could meet with the comprehensive performance of high performance concrete used in passenger dedicated line engineering.The problems of polycarboxylates water-reducing admixtures existed in the engineering application of were analyzed.At present the key for polycarboxylates application was to settle the compatibility between the water-reducing admixture and the cement and to keep the quality retention of this admixture.

An Improved Method for Modeling Spatial Distribution of δD in Surface Snow over Antarctic Ice Sheet

Using the recent compilation of the isotopic composition data of surface snow of Antarctic ice sheet, we proposed an improved interpolation method of δD, which utilizes geographical factors （i.e., latitude and altitude） as the primary predictors and incorporates inverse distance weighting （IDW） technique. The method was applied to a high-resolution digital elevation model （DEM） to produce a grid map of multi-year mean δD values with lkm spatial resolution for Antarctica. The mean absolute deviation between observed and estimated data in the map is about 5.4‰, and the standard deviation is 9‰. The resulting δD pattern resembles well known characteristics such as the depletion of the heavy isotopes with increasing latitude and distance from coast line, but also reveals the complex topographic effects.

Geoid Deformation and Elevation Influence Caused by Building Loading

The paper studies the ground vertical deformation and the geoid undulation caused by loading of neighboring buildings, based on the loading tides theory. The influence on elevation is also considered. The results show that the ground vertical deformation and the geoid undulation both reach millimeter magnitude. Therefore, it is obvious that the building loading significantly affects the precise engineering surveying, and it must be seriously considered in application.

Biomechanism of impact resistance in the woodpecker's head and its application

The woodpecker does not suffer head/eye impact injuries while drumming on a tree trunk with high acceleration （more than 1000xg） and high frequency. The mechanism that protects the woodpecker＇s head has aroused the interest of ornithologists, biologists and scientists in the areas of mechanical engineering, material science and electronics engineering. This article reviews the literature on the biomechanisms and materials responsible for protecting the woodpecker from head impact injury and their applications in engineering and human protection.

Progress of Jinping Underground laboratory for Nuclear Astrophysics(JUNA)

Jinping Underground laboratory for Nuclear Astrophysics(JUNA) will take the advantage of the ultra-low background of CJPL lab and high current accelerator based on an ECR source and a highly sensitive detector to directly study for the first time a number of crucial reactions occurring at their relevant stellar energies during the evolution of hydrostatic stars. In its first phase, JUNA aims at the direct measurements of^(25)Mg(p,γ)^(26)Al,^(19)F(p,α)^(16)O,^(13)C(α,n)^(16)O and ^(12)C(α,γ)^(16)O reactions. The experimental setup,which includes an accelerator system with high stability and high intensity, a detector system, and a shielding material with low background, will be established during the above research. The current progress of JUNA will be given.