黄山松木材物理力学性质研究

测计黄山松木材的物理力学性质，结果表明，黄山松木材主要物理力学性质属中等；某些指标优于同类树种马尾松等；幼龄材与成熟材材质差异显著；木材容许应力优于红松、落叶松等木材，完全可用作建筑材料。

某抽水蓄能电站长探洞花岗岩岩体力学研究

不同时期、不同环境下形成的花岗岩岩体,具有不同的物理力学性质。为研究某抽水蓄能电站地下厂房花岗岩岩体力学特性,通过长探洞,进行现场地震波测试、变形试验、岩/岩抗剪试验、岩/砼抗剪试验、三维地应力试验等试验和室内物理力学试验,得出花岗岩岩体的密度、抗压强度、软化系数、泊松比、变形模量、抗剪强度、地应力等参数,再结合相应规范规程,参考其它项目,最后给出该项目地下厂房花岗岩岩体物理力学参数,为工程建设提供真实可靠的保障。

Physical and Mechanical Properties of Coral Sand in the Nansha Islands

Coral sand is a unique material developed in the tropical ocean environment, which is mainly composed of coral and other marine organism debris, with the CaCO3 content up to 96 %. It has special physical and mechanical properties due to its composition, structure and sedimentary environment. In this contribution, we discuss its specific gravity, porosity ratio compressibility, crushing, shearing and intensity for coral sand samples from the Nansha islands based on laboratory mechanical tests. Our results show distinct high porosity ratio, high friction angle and low intensity as compared with the quartz sand. We believe that grain crushing is the main factor that influences the deformation and strength of coral sand. Comprehensive study on the physical and mechanical properties of coral sands is significant in providing reliable scientific parameters to construction on coral islet, and thus avoids accidents in construction.

A first-principle calculation of structural,mechanical and electronic properties of titanium borides

The first-principle calculations are performed to investigate the structural,mechanical and electronic properties of titanium borides （Ti2B,TiB and TiB2）.Those calculated lattice parameters are in good agreement with the experimental data and previous theoretical values.All these borides are found to be mechanically stable at ambient pressure.Compared with parent metal Ti （120 GPa）,the larger bulk modulus of these borides increase successively with the increase of the boron content in three borides,which may be due to direction bonding introduced by the boron atoms in the lattice and the strong covalent Ti-B bonds.Additionally,TiB can be regarded as a candidate of incompressible and hard material besides TiB2.Furthermore,the elastic anisotropy and Debye temperatures are also discussed by investigating the elastic constants and moduli.Electronic density of states and atomic Mulliken charges analysis show that chemical bonding in these titanium borides is a complex mixture of covalent,ionic,and metallic characters.

Wood Physical and Mechanical Properties of Populus × canadensis Moench and Populus ×euramericana(Dode) Guinier cv. Gelrica

The physical-mechanical properties of Populus x canadensis Moench and Populus x euramericana （Dode） Guinier cv. Gelrica were studied to provide theoret- ical and scientific bases for the directional breeding and efficient use of artificial forests with P. canadensis and P. euramericana Gelrica. The results showed the air-dried density, basic density of P. canadensis were 0.468 g/cm3 and 0.372 g/cm3, respectively; the shrinkage coefficient of radial, tangential and volume were 0.133%, 0.270% and 0.553%, respectively;the modulus of elasticity in static bending, the bending strength and the compressive strength parallel to grain were 9 302.99 MPa, 79.69 MPa and 40.32 Mpa, respectively. As for the P. euramericana Gelrica, the air-dried density, basic densitywere 0.453 and 0.355 g/cm3, respectively; the shrink- age coefficient of radial, tangential and volume were 0.205%, 0.304% and 0.554%, respectively; the modulus of elasticity in static bending, the bending strength and the compressive strength parallel to grain were 9 014.44, 55.87 and 33.09 Mpa respectively. Comprehensive analysis of the indicators showed that the properties of P. canadensis were better than those of P.euramericana Gelrica.

Effects of Freeze–thaw Cycles on Soil Mechanical and Physical Properties in the Qinghai–Tibet Plateau

Extreme freeze-thaw action occurs on the Qinghai-Tibet Plateau due to its unique climate resulting from high elevation and cold temperature.This action causes damage to the surface soil structure, as soil erosion in the Qinghai-Tibet Plateau is dominated by freeze-thaw erosion.In this research,freezing–thawing process of the soil samples collected from the Qinghai–Tibet Plateau was carried out by laboratory experiments to determinate the volume variation of soil as well as physical and mechanical properties, such as porosity, granularity and uniaxial compressive strength, after the soil experiences various freeze–thaw cycles.Results show that cohesion and uniaxial compressive strength decreased as the volume and porosity of the soil increased after experiencing various freeze–thaw cycles, especially in the first six freeze–thaw cycles.Consequently, the physical and mechanical properties of the soil were altered.However, granularity and internal friction angle did not vary significantly with an increase in the freeze–thaw cycle.The structural damage among soil particles due to frozen water expansion was the major cause of changes in soil mechanical behavior in the Qinghai–Tibet Plateau.

Evaluation of Soil Fertility Under Different Cupressus chengiana Forests Using Multivariate Approach

The distribution and growing conditions of Cupressus chengiana forests along with the physical and chemical properties of soils in Northwest Sichuan were studied in 2002 to investigate the conditions and characteristics of soil fertility of C. chengiana and to compare and investigate differences of soil fertility for six C. chengiana populations and their relationships with vegetation, climate and disturbance. The results of the study at 0-20 cm soil depth showed that 1) significant differences (P < 0.05) existed among populations for soil bulk density, soil total porosity, capillary porosity, maximum water-holding capacity, capillary water-holding capacity and topsoil natural water content; 2) chemical characteristics of soil organic matter, total N, total P, alkali-hydrolyzable N, available P, available K and cation exchange capacity were significantly different among the populations; and 3) based on the significant effect of soil fertility factors on forest growth, soil physical and chemical characteristics could be selected as an integrated fertility index (IFI) for evaluation of different C. chengiana populations. Principal component and cluster analyses showed significant differences probably due to the difference of vegetation conditions, management measurements, human-induced disturbances and environmental factors. In order to protect the soil ecological functions in fragile ecological regions, C. chengiana could be used in programs enclosing the hill for natural afforestation, natural forest protection programs, and programs replacing agriculture with afforestation measures.

Analytical solution for stress and deformation of the mining floor based on integral transform

Following exploitation of a coal seam, the final stress field is the sum of in situ stress field and an excavation stress field. Based on this feature, we firstly established a mechanics analytical model of the mining floor strata. Then the study applied Fourier integral transform to solve a biharmonic equation,obtaining the analytical solution of the stress and displacement of the mining floor. Additionally, this investigation used the Mohr–Coulomb yield criterion to determine the plastic failure depth of the floor strata. The calculation process showed that the plastic failure depth of the floor and floor heave are related to the mining width, burial depth and physical–mechanical properties. The results from an example show that the curve of the plastic failure depth of the mining floor is characterized by a funnel shape and the maximum failure depth generates in the middle of mining floor; and that the maximum and minimum principal stresses change distinctly in the shallow layer and tend to a fixed value with an increase in depth. Based on the displacement results, the maximum floor heave appears in the middle of the stope and its value is 0.107 m. This will provide a basis for floor control. Lastly, we have verified the analytical results using FLAC3 Dto simulate floor excavation and find that there is some deviation between the two results, but their overall tendency is consistent which illustrates that the analysis method can well solve the stress and displacement of the floor.

Optimum cutting speed of block-cutting machines in natural stones for energy saving

Energy consumption of block-cutting machines represents a major cost item in the processing of travertines and other natural stones. Therefore, determining the optimum sawing conditions for a particular stone is of major importance in the natural stone-processing industry. An experimental study was carried out utilizing a fully instrumented block-cutter to investigate the sawing performances of five different types of travertine blocks during cutting with a circular diamond saw. The sawing tests were performed in the down-cutting mode. Performance measurements were determined by measuring the cutting speed and energy consumption. Then, specific energy was determined. The one main cutting parameter, cutting speed, was varied in the investigation of optimum cutting performance. Furthermore, some physico-mechanical properties of file travertine blocks were determined in the laboratory. As a result, it is found that the energy consumption （specific energy） of block cutting machines is highly affected by cutting speed. It is determined that specific energy value usually decreases when cutting speed increases. When the cutting speed is higher than the determined value, the diamond saw can become stuck in the travertine block; this situation can be a problem for the block-cutting machine. As a result, the optimum cutting speed obtained for the travertine mines examined is approximately 1.5-2.0 m/min.

Physical and mechanical properties of sandstone containing a single fissure after exposure to high temperatures

In order to investigate the physical and mechanical properties of sandstone containing fissures after exposure to high temperatures,fissures with different angles α were prefabricated in the plate sandstone samples,and the processed samples were then heated at 5 different temperatures.Indoor uniaxial compression was conducted to analyze the change rules of physical properties of sandstone after exposure to high temperature,and the deformation,strength and failure characteristics of sandstone containing fissures.The results show that,with increasing temperature,the volume of sandstone increases gradually while the quality and density decrease gradually,and the color of sandstone remains basically unchanged while the brightness increases markedly when the temperature is higher than 585 ℃;the peak strength of sandstone containing fissures first decreases then increases when the temperature is between 25℃and 400℃.The peak strain of sandstone containing fissures increases gradually while the average modulus decreases gradually with increasing temperature,and the mechanical properties of sandstone show obvious deterioration after 400 ℃.The peak strain of sandstone containing fissures increases gradually while the average modulus decreases gradually with increasing temperature;with increasing angle αof the fissure,the evolution characteristics of the macro-mechanical parameters of sandstone are closely related to the their own mechanical properties.When the temperature is 800 ℃,the correlation between the peak strength and average modulus of sandstone and the angle α of the fissure is obviously weakened.The failure modes of sandstone containing fissures after high temperature exposure are of three different kinds including:tensile crack failure,tensile and shear cracks mixed failure,and shear crack failure.Tensile and shear crack mixed failure occur mainly at low temperatures and small angles;tensile crack failure occurs at high temperatures and large angles.

Information Entropy Squeezing for a Atom in Mode-Mode Competition System

The entropy squeezing properties for a two-level atom interacting with a two-mode field via two differentcompeting transitions are investigated from a quantum information point of view.The influences of the initial state of thesystem and the relative coupling strength between the atom and the field on the atomic information entropy squeezingare discussed.Our results show that the squeezed direction and the frequency of the information entropy squeezing canbe controlled by choosing the phase of the atom dipole and the relative competing strength of atom-field,respectively.We find that,under the same condition,no atomic variance squeezing is predicted from the HUR while optimal entropysqueezing is obtained from the EUR,so the quantum information entropy is a remarkable precision measure for theatomic squeezing in the considered system.

Influences of Soil Physical Properties on Water-Supplying Capacity

The water-supplying capacity of two agricultural soils, red soil in Jiangxi Province and meadow soil in Henan Province, was assessed mainly using physical investigations. The reticulated mottting horizon in the red soil was a horizon limiting roots distribution due to its high density and hardness in structure and low pH (pH 5.05). The resistance of the red soil to drought hazard was poor because of its low water-supply capacity and poor hydraulic conductivity. The meadow soil had superior profile infiltration to that of the red soil and great available water-storage capacity) which resulted in low run-off loss, especially in the wheat-growth season. It was difficult for water stored in the deep layers of the meadow soil to reach the surface due to the low unsaturated hydraulic conductivity of its clay-rich horizon in subsoil. However, water stored in deep layers was still available because the roots could extend to the deep layers due to the relatively low density in soil structure.

Sediment consolidation settlement of Chengbei Sea area in the northern Huanghe River subaqueous delta,China

One of the most important factors controlling the morphology of the modem Huanghe （Yellow） River delta is consolidation settlement, which is impacted by fast deposition, high water content, and low density of seafloor sediment. Consolidation settlement of the Huanghe River subaqueous delta was studied based on field data, laboratory experiments on 12 drill holes, and the one-dimensional consolidation theory. Results show that vertical sediment characteristics varied greatly in the rapidly forming sedimentary bodies of the modem Huanghe River subaqueous delta. Sediments in the upper parts of drill holes were coarser than those in the deeper parts, and other physical and mechanical properties changed accordingly. On the basis of the one-dimensional consolidation theory and drilling depth, the final consolidation settlement of drill holes was between 0.6 m and 2.8 m, and the mean settlement of unit depth was at 1.5-3.5 cm/m. It takes about 15-20 years for the consolidation degree to reach 90% and the average sedimentation rate within the overlying 50 m strata was at 5 cm/a to 12 cm/a. This study helps to forecast the final consolidation settlement and settlement rate of the modem Huanghe River subaqueous delta, which provides key geotechnical information for marine engineers.

PROGRESS OF ACOUSTIC WAVE TECHNIQUE ANDITS APPLICATION IN UNDERGROUND PRESSURE MEASUREMENT

This paper carries out tbe experirnent study on the correlation between am stress-strain process of rock samples and the acoustie parameter change of rock by using the measurement system of KS acoustic wave data processing device. On the spot, the stability of surrounding rock is studied by means of experiments on the relationship between the change process (from elastie to plastic failure zone) in surrounding rock of roadway and the change law of acoustic parameters of rock. These acoustie parameters inelude wave amplitude, spectral amplitude, spectrum area, spectral density,wave veloeity and attenuation coefficient etc.

Coherence of a Chain of Chaotic Oscillators in a Nonlinear Gyrotropic Medium

We investigate the generalized Kuhn＇s model, namely, a chain of nonlinear chaotic oscillators describing a nonlinear gyrotropic medium. It is shown that despite the chaotic behavior of separate oscillators the chain preserves some coherency as a whole. The relation between the chain synchronization and the physical properties of a random mean field is established.

Effect of Microwave Power on the Zn2SnO4 Synthesis and Its Use for Photodegradation of Phenol

Spinel structure Zn2SnO4 was successfully synthesized by microwave-assisted hydrothermal process. The effects of the microwave power on the formation and physical properties of the Zn2SnO4 particles are discussed. The products were characterized by X-ray diffraction, atomic force microscopy, infrared spectroscopy, and N2 adsorption. The results indicated that the microwave power had important influence on the formation of the spinel phase. The results also revealed that the physical properties of Zn2SnO4 particles did not change with the increase of the microwave power above 600 W, with 20 min of reaction time. Furthermore, the photocatalytic activity of the Zn2SnO4 particles for the phenol degradation under sunlight was also investigated.

Thermodynamic Properties of Caprolactam Ionic Liquids

A series of caprolactam ionic liquids(ILs) containing incorporated halide anions were synthesized.Their physical properties,such as melting points,heats of fusion and heat capacities,were measured by differential scanning calorimeter(DSC).The results indicate that these ionic liquids exhibit proper melting points,high value of heats of fusion,and satisfying heat capacities which are suitable for thermal energy storage applications.

A Micro-Mechanism Model for Porous Media

Based on the tortuous-expanding path/channel model,a micro-mechanism model for porous media is developed.The proposed model is expressed as a function of tortuosity,porosity,resistance coefficient,and fluid properties.Every parameter in the proposed model has clear physical meaning.The results show that the model predictions are ingood agreement with those from the existing experimental data.

Solution of Modern Thermo Physical Problems of Applied External and Internal Aerodynamics with Dark Matter-Energy Simulation

The paper is devoted to new, experimentally registered thermo physical problems of high temperature applied external and internal aerodynamics which is defined first of all by intensive interaction of the gaseous media and thermal radiation. The first report section analyses basic complexities of designing high temperature air breathing engines related to origin of so-called ＂unexpected＂ heat of working process. The next parts of the report consider physical, chemical and plasma features of aerodynamics of reentry space blunt bodies and meteors with specified account of thermal radiation influence. Our solutions are based on the classical Dark Matter-Energy simulation. We present special experimental data for Dark Matter pressure registration on the earth conditions.

High-P/T experimental studies and water in the silicate mantle

Water(or H) in the silicate mantle is a key element in influencing Earth's climate, habitability, geochemical evolution, geophysical properties and geodynamical processes, and has received increasing attention in the past decades. Experimental work under simulated high-pressure and high-temperature conditions is a powerful tool in characterizing the species, distribution, storage capacity and various physicochemical impacts of water in the mantle. In recent years, significant approaches have been acquired about some key physical, chemical and dynamical properties of water in the mantle and their various impacts, as a result of extensive studies by high-pressure and temperature experiments, and our knowledge of Earth's water cycle, especially the deep water cycle, on both temporal and spatial scales has been greatly enhanced. In this paper, a brief review based mainly on experimental studies is presented concerning the current understanding and some recent approaches of water in the silicate mantle, such as the possible origin, amount, storage and the effect on mantle properties.