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The selection of the dynamical properties of machines is one of the methods enhancing their durability and reliability.
Such task may be regarded as a support of the stage of designing mechanical systems, where an essential element is the fulfilment of the required dynamical properties.
These properties may be represented in a graphic or analytical form, or in a form of sequential zeros and poles, which shall be considered in the paper.
These requirements apply to obtaining the set dynamic properties of systems with control as characteristic functions (impedance, mobility).
The value of amplification factors of the control system is determined by comparing the characteristics (4), (5) and (6) with the characteristic of dynamic flexibility of the control system in the force feedback loop (8).

The state of stress that exists in welds during and following the thermal cycle and how this affects microstructure and properties of the joining can be predicted by modeling and observations during laboratory experiments and by analyzing results of case studies.
The character of important physical-chemical processes in a welding pool and near to its border influences technological and service properties of a welding joint.
The jet of plasma affecting a surface of a pool, and circulates it.
The account of these factors requires the heat conduction and heat and mass transfer, the pool hydrodynamics, and other variables to be included into the equations system.
Dependence of physical properties of a material on temperature and the requirements of welding defines influence of different forces on liquid metal convection.

To study the effect of mechanical interface on vibration behavior of industrial product, it is necessary to capture vibration data and investigate modal properties.
Some typical mechanical joints must have a significant influence on the dynamics and do make change of structural response properties.
And the dynamic properties of the mechanical system such as the natural frequency, damping ratio were also obtained with the experimental measurement for specimens.
The bolted joint specimen with free boundary was shocked by transient impulse in the horizontal direction and time-domain response properties for different preload levels were recorded in experimental results.
The processed FRF data as shown in Fig.4 not only shows the relationship between excitation and response signal but also reveals structural inherent properties.

Research Progress for Gypsum Retarder Ren Xiao-qiong1, Wu Ya-nan1,2,Li Ying1,3 ,Lin Mo-han1 ,Zhao Feng-qing1,a 1Hebei University of Science & Technology, Shijiazhuang 050018, PR China 2Hebei Engineering Research Center of Solid Wastes Utilization Shijiazhuang 050018, PR China 3Hebei Engineering Research Center of Pharmaceutical and Chemical Engineering Shijiazhuang 050018, PR China ,aemail:zhaofq3366@126.com(corresponding author) Keywords: Building gypsum; Retarder; Mechanical properties; Waste mycelium Abstract.
Although the effects of organic acids and phosphates have better retarding performances, there is still obvious a shortcoming that the mechanical strength reduces largely with time going by.
In the case of citric acid as a retarder, the suitable dosage should not exceed 0.1%. pH and temperature and other factors have a greater impact on its retarding effect.
Conclusion Gypsum retarder is an important material of building materials, and its performance will directly affect the performance of gypsum products.
Factors affecting citric acid retarding effect on the building plaster [J].

In this paper, based on uniaxial tension experiments of TRC plates, the loading behavior of TRC plates and influence factors on their ultimate load capacity are discussed.
Fig.1 Fig.2 Different reinforced structures Glass fibers used in the experiment Many scholars have achievements on mechanical properties of TRC structures both theoretically and practically.
In this paper, the basic properties of TRC plates are discussed both experimentally and theoretically.
Experimental investigation and results The mechanical properties of textiles and matrix.
Using the law of mixture, we can explain it [7] and simulate its mechanical properties before cracking.

The reliability of the electronic modules could be considered as expression of solder joints functionality (SJF) relating to working conditions and unique defined by their electrical, mechanical and thermal properties.
These properties are in close connection with the solder joints microstructures, result of the soldering Process temperature gradient action over the trinomial solder alloy Paste, Pin and Pad.
Taking into account his role as driving force in innovation with a horizontal position in global economy, three characteristic levels of the manufacturing processes in the electronics industry influencing factors could be identified: A.
The reliability of the electronic modules could be considered as expression of solder joints functionality (SJF) relating to working conditions and unique defined by their electrical, mechanical and thermal properties.
Indirect defects, as consequences of a manufacturing, are caused by impaired of the mechanical and/or thermal functionality of the solder joints [4, 5, 6], by changes in general at microstructural level during manufacture or during storage, transport or operation due to manufacturing defects unidentified after assembling process or appearing due to the action of environmental factors.

The functional similarity criteria and structural similarity criteria derived from this method can accurately describe the similar properties of mechanical components under different similar requirements and can be used to set up the experimental model.
Function is the nature when the components affect and exchange with the external environment, it’s the pattern of manifestation with the external environment.
Structure is the nature when the inner elements affect and impact with each other.
And the structure here is not the structure of the system, but the inner factor of the components for example size, modulus and other physical parameters.
The similarity theory and its application in mechanical engineering[J].

Pretension is a key factor affecting the performance of rock bolt.
Many factors affect the relationship between nut tightening torque and pretension [11], one of the important factors is the bolt thread machining accuracy.
The factors affecting the bolt threaded accuracy The main factors affecting the accuracy of the bolt thread are as follows: (1) The bolt material.
Table 1 lists the mechanical properties of SMG500 bolt steel.
Table 1 Mechanical properties of SGM500 rebar for rock bolts Specimen No.

A total 72 cubes mortar is cast and determined their properties of chemical and mechanical.
The first part deals to chemical properties of the WPSA and BA and second part is evaluated the mechanical properties especially the compression strength of the mortar.
Quantity of cement is the factors that affected the reactivity of aggregate.
Du, Use of Waste Glass as Sand in Mortar: part I – Fresh, Mechanical and Durability Properties, Cement and Concrete Composite. 35 (2013) 109 -117
Prince, Physical and Mechanical Properties of Mortars Containing PET and PC Waste Aggregates, Waste Management. 30 (2010) 2312 – 2320

Based on the experimental materials: specification for 30 mm x 25 mm x 10 mm specimens of 180 pieces of walnut, moisture content is about 10-12%. 2.2 design of orthogonal experiment In this experiment, considering the production line, pressure, time and dosage of curing agent in the three factors, if three factors comprehensive combination shall be 3 after = 27 kinds of combination of experiments, and the number of repeat each combination has not been considered, so the mining height are broken, rapid and economic efficiency of the orthogonal design method, experiments with 3 factors and 3 levels L9 (3) after the orthogonal experiment, the factors of a class are shown in table 2-2 experimental results and data processing are shown in table 3-1 Tab.2-2 Orthogonal test table Factor No Time（h） presure（MPa） The amount of MDI (the equivalent of dry glue quality) 1 1 1 10％ 2 1 2 20％ 3 1 3 30％ 4 2 1 30％ 5 2 2 10％ 6 2 3 20％ 7 3 1 20％ 8 3 2 30％ 9 3 3 10％ 2.3 the preparation of modified
Simulating finger-joint performance based on localized constituent lumber properties[J].
Localized modulus-of-elasticity properties of E-rated spruce-pine laminating lumber.
[11] Hao Jincheng, Wang Shixin, Li Jinjie, glued laminated wood configuration and strength properties of [J], forestry science and technology, 1997,22 (1):38-39
[12] Gu Jiyou, Cheng Ruixiang, larch, birch and oak wood adhesive bonding properties of integration of [J], wood processing machinery, 2003,14 (2):1-4