Search results

Third is mechanical vibration effect inducing loess landslide.
From many times under the influence of human activities loess landslide disaster can be seen, each time landslide caused an extremely serious loss of life and property.
On May 16, 2009, Lanzhou happened landslide (Fig. 2), it mainly because of slope mass excavation at bottom to housing estate development and formed the high and steep slope , slopes top vegetation caused water infiltration, it caused 7 people killed and buildings were destroyed and formed serious social unstable factors.
However, these engineering activity not only correlation, but also with inducing factors intercoupling of the natural landslide, engineering loess landslide disaster complex varied, the characteristics of complex displays for: 1) Disasters frequent occurrence, universal. 2) Mechanism of factor is complicated, particularity; 3) Disasters it is difficult to identify, latent; 4) Disasters is not easy to predict.
This kind of slide is many geological factors superimposed effect and human engineering force together formative.

A New Method of Characterization on Microstructure of Casting Alloy Zheng Liua, Xiao-mei Liub Faculty of Mechanical and Electronic Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China a liukk66@163.com, b liuxm66@163.com Keywords: A356 alloy, fractal dimension, primary phase, morphology, casting Abstract.
Introduction There are the great effects of the morphology of microstructure in casting alloy on the forming ability and the mechanical properties, in which one of the microstructural characteristics in casting alloy with good forming properties has certain amount of particle-like microstructure [1].
At present, shape factor is a more accurate analysis method to quantitatively describe the phase morphology in metallic material [2].
During formation and growth of primary phase, because of affecting by preparing condition and external physical field (for example pouring temperature, isothermal holding, ultrasonic or mechanical disturbance, addition of modifier and so on), there will be change on the morphology, size and structure for primary phase grain, at the same time, there is other change, included growth and migration of the grain, even fuse and separation of the grain to make morphology of the grain change.
There are the numerous complicated factors affecting the morphology during evolution of primary phase morphology in the casting alloy, in which they are nonlinear in essence.

There has heretofore been a large number of research on the acicular ferrite steel [4, 5, 6], and the results show that compared with the traditional ferrite-pearlite steel, the acicular ferrite steel has better comprehensive mechanical property, and also has excellent welding performance and corrosion resistance.
Fatigue performance has become one of the most important performances of bridge steel for it directly affects the service life of the steel bridge.
In this paper, the fatigue limit and S-N curve of Q500q bridge steel were obtained by high-cycle fatigue test, the experimental steel fatigue properties have been studied through the fracture morphology observation and the analysis of fatigue crack initiation and propagation process.
The steel plates were produced using the thermo-mechanical control process (TMCP) that involves a controlled rolling and on-line accelerated cooling.
The crack tip stress intensity factor, K Ι , was calculated using the following equation [10]: Where σ is nominal stress, a is crack length and Y is form factor of the specimen.

Among these earthquakes，the 8.5 Haiyuan earthquake in 1920 and the 8.0 Gulang earthquake in 1927 caused serious disasters and the loss of lives and properties was huge[2].
Because of the special characteristics of loess in thickness, geomorphology and soil mechanical properties, etc. the earthquake damages are serious and the range is large.
The peak acceleration, as far as site factors are concerned, is mainly affected by the thickness of soil, topography, conformation and the soil properties, etc.
Among these factors, the overburden thickness and the slope grade are two important factors influencing earthquake damage.
As a result, the influence of these two factors on ground motion amplification was analyzed and the distribution of the peak acceleration under different seismic load was obtained as well.

As the portable exoskeleton system functions as an assistant device for human body weight-bearing exercises, human factors must be taken into account in designing of the mechanism, which are design constraints brought about by the upper limit of human body weight-bearing capacity and human body size.
As the most important parameter that affecting the particle speed renewal, the inertial weight ω directly performs control over speed and direction.
To set the appropriate material properties in ANSYS, select the SOLID92 units, and assign the corresponding element attributes for each component in the mechanical structure of portable exoskeleton, the finite element model can be obtained, as shown in Fig. 2.
Mechanical Science And Technology. 2007,26(8):1063-70
Beijing: Mechanical Industry Press;2008.

While physical (strength, flexibility, etc.) and chemical (e.g. stability) characteristics are among the outstanding properties of all-surface-atoms graphene, the added value of graphene in electronics and optoelectronics, derives from its very special, intrinsic electronic structure, the zero band gap and linear dispersion of the p band at the Fermi level.
As a second observation, the imperfections of wafer slicing of the on-axis cut 6H-SiC crystal can lead to intrinsic defect properties of the surface in a macroscopic order (Fig. 2).
As a basic discussion about the graphene-on-SiC deposition mechanism, we contemplate that a priori a reduced number of surface structural defects, as it results from CMP pre-graphene deposition substrate conditioning, might reduce the average amount of graphene flakes formed if those factors determine the graphene nucleation sites.
Further study of the impact of CMP for specific-shape graphene deposition and the clarification of the predominant factors, e.g. step bunching, faceting, graphene nucleation points, growth propagation, etc., should be addressed.
Tanaka et al., The atomic step induced by off angle CMP influences the electrical properties of the SiC surface, Materials Science Forum 717-720 (2012) 569-572

From the obtained results it is not easy to conclude a definitive conclusion or to set the boundaries between the factors that are responsible for wear resistance.
The small particles of sand and rocks affect as small abrasive particles which destroy the pressing tool by several wear mechanisms [3].
A very important factor in the pressing of a briquette is the pressing temperature which should be from 80°C to 220°C [1,3].
According to [1] it is desirable that the pressing temperature is in the range from 160°C to 220°C, because the mechanical properties of the briquettes and their other properties (heat value) are very plausible.
It happened because the nitrided layer contained the so called ε phase and so called grids of nitrides, which degraded the mechanical properties of the layer as a result of different chemical composition on the edge of the carbides and the steel matrix.

However, the properties of the adhesive can also be classified as a failure criterion.
Several authors have found that the environmental factors can affect the properties of an adhesive joint and ultimate mechanical performance of the adhesive joint [4-6].
Thus, these factors must be considered as critical factors in determining long term durability of adhesive joint.
This is due to the change in adhesive properties.
This is because at high temperature, the failure is determined by the change of mechanical properties of adhesive.

CMC are used in many industries, for example, automotive, aircraft, space, chemical and energy industries, shipbuilding, oil- production and refining due to the possibility of combining different properties in one part.
St/Al clad composites are characterized by a combination of high mechanical properties and toughness, good corrosion resistance, high thermal and electrical conductivity, and find application in automobile and shipbuilding industries as well as in the manufacturing of the building panels and bearings [1–3].
For this reason, study of the influence of various factors on the bond strength between dissimilar materials is actual scientific direction.
Jafarian, Effect of thermal tempering on microstructure and mechanical properties of Mg-AZ31/Al-6061 diffusion bonding, Materials Science and Engineering A, 666 (2016) 372–379
Taherizadeh, Effect of Roughness and Surface Hardening on the Mechanical Properties of Three-Layered Brass/IF Steel/Brass Composite, Trans.

Total energy of underwater explosion can be regarded as the effective energy explosive.The mian idea of study the relationship between formulation and energy output structure,is to increase the total explosion energy based on reasonable distribution of shock wave energy and bubble energy. 2.2 The technical approach of underwater powerful explosives The formula design of underwater powerful explosives is a very complicated subject.It does not only include the research on energy structure properties by underwater explosion,but also involves many subjects such as mechanics, chemistry,physics,charging process and cost.There are many problems which remain to be researched.In this paper,we study of explosive energy.And the technical approachs of underwater powerful explosivesidentified we used in underwater weapons described as follows: (1)The loss of explosive energy increases with the increase of explosion pressure.The improvement of explosion heat is increased the output energy of explosion.Therefore
(2)The detonation mechanism of aluminized explosive shows that the oxidation reaction of aluminum powder obviously increase the decay time constantof of underwater explosion shock wave and reduce the explosive blast and decay rate of energy density.The kinetic characteristic of aluminum powder is one of the important factors that affected the underwater explosion shock wave characteristics[4]
(3)To ensure the mechanical properties of explosives,sensitivity,charging technology and economy and other performance,a way of improving the energy is to reduce the mixed explosives inert binder or switch energetic blender[5].
Aluminized explosives and explosive energy design with meso system components are also closely linked,such as Al powder particle size,surface area and other factors affect meso explosion heat,detonation pressure, detonation velocity and energy of wavefront consumption.Charge density and the charge process also have a significant impact on the structure of energy output of aluminized explosives.Therefore,for the design of aluminized energy explosives,it should be calculated on the basis of repeated theoretical repeated experiments,in order to obtain a good overall performance for explosives[6]. 2.3 Formula design Explosive JULH-1 is made up of RDX as its main explosive,AP as its oxidizing agent,Al as its raw materials and HTPB as its binder.Making the raw materials to micor order or sub-nanometerorder by ultrafine grinding and using the technology of grain composition,several experiments of measuring energy output structure were carried out under water and some scientific and reasonable
The ultrafine technology is introduced to JULH-1,in which part of RDX and ammonium perchlorate processed by ultra-attenuation,particle size reach micron or sub-nanometer.Contrast the explosion energy,JULH-1 output shock wave energy,bubble energy and the total energy is much higher than the domestic popular explosives of Underwater Ordance in the main charge of TNT,RS211,THL,etc.Because the surface of RDX explosives were significantly increased after super fine crushing,an explosion reaction, the reaction speed accelerated, the energy loss in the process of detonation decreased.The ultrafine ammonium perchlorate can improve the physical structure, mechanical properties of explosive mixture and accelerate the detonation reaction speed,reduce the energy loss in the water,can effectively improve the water energy output, improve the level of the explosive power[7]. 4.