Due to the difference of crystallization temperature and enthalpy for free water and interfacial water during the course of cooling, a series of water-in-oil emulsions were studied experimentally by means of differential scanning calorimetry (DSC). The free water and interfacial water and to measure the time-dependent changes were characterized. From the result can only find one exothermic peak corresponding to the interfacial water at about -40 ℃ when the solubilized water mass fraction 15%. By increasing the amount of the solubilized water to 15%, a new significant exothermic peak is present (at -18 ℃) which is attributed to free water. Both the crystallization temperature of free water and interfacial water are affected by the concentration of solubilized water weekly. The stabilization of the 30%W/O emulsion is decreased with the increase of time placed, and the concentration of interfacial water is also reduced. The peak for the crystallization of interfacial water can not found in the DSC thermogram for the sample prepared over 8 days, and the area of the exothermic peak for the free water crystallization is increased apparently. The change for DSC thermogram indicates that the stabilization of 30%W/O emulsion is destroyed absolutely. 

The study of de － emulsification mechanism for water － in － oil emulsions by electrostatic coalescence in rectangular flow channel was the basis and prerequisite of developing vessel internal electrostatic coalescer．The influence factors of electric field intensity with insulating coating in rectangular flow channel and coalescence mechanism of dispersed droplets under homogeneous alternating current electric field were analyzed ．Then the continuous－flow electro－coalescence experimental apparatus with rectangular flow channel was designed ．Based on this apparatus ，the effects of electric field intensity，pulsed
frequency ，pulse width ratio ，flow velocity to the electrostatic coalescing characteristics of dispersed droplets were studied by applying rectangular － wave high－voltag and high－frequency pulsed alternating current with water－ in －oil emulsions．The experimental results show that electric field intensity and flow velocity play an important role in electrostatic coalescing process of dispersed droplets，and have an optimal operating condition．

A two － dimensional axisymmetric model of friction hydro pillar processing （FHPP） was established base on
Gambit software ．Using the commercial computational fluid dynamics software Fluent ， the numerical simulation of plastic
metal flow pattern was carried out in steady phase of FHPP ．While keeping the other parameters constantly during the process
of numerical simulation ，the velocity field and static pressure field distribution change of ideal metal plastic fluid during the
forming process were analyzed by changing only one critical parameter respectively ，such as the radial clearance between metal
stud and the base hole ，the material viscosity ，the rotary speed of metal stud ，the feed rate of metal stud and the bottom shape
of the base hole ．The result show that the static pressure distribution of plastic metal is affected remarkably by the feed rate （i ．
e ．the axial force） and the material viscosity of metal stud ，and has little to do with the rotary speed and the radial clearance ．
Although the feed rate and the radial clearance have little influence on the velocity distribution of plastic metal ，the effect of
rotary speed is relatively remarkable ，especially for the material neighboring to the wall of the velocity inlet and nearby the
metal stud ．The flow condition of the plastic metal material can be improved by changing the bottom shape of the base hole ，
which can also reveal the reason why there exist some defects at the bottom of the hole ．The above － mentioned research can
provide some guidance to the future experimental study adopting appropriate parametric combination ，and can also lay solid
foundation for the future numerical simulation by thermo － mechanical coupling ．

aking the surface-contact model between rigid flat punch and elastic half-space as the research subject, and through comparing the results of analytical solution and numerical simulation by the finite element method (FEM) software MSC.Marc, it is determined that the non-uniform meshing method and the third grade FEM calculation are reliable as to the surface-contact problem with definite contact area. For the most fundamental surface-contact problem involved with friction hydro pillar processing in friction stitch welding, the normal stress on the contact surface increases quadratically from center to the marginal side. The diameter of the metal stud and the applied external load has more influence to the distribution of normal stress on the contact surface, while the influence of radial clearance, the material combination between the metal stud and the predrilled hole are relatively small.

he hyperbaric welding test chamber and the automatic GTAW machine were developed for high air ambient pressures. The arc static characteristics curves were tested under 0.1~0.7 MPa air ambient pressures, and the mathematical model of GTAW between arc voltage and parameters such as air ambient pressure, arc length, and current, was created. Based on arc static characteristics and the arc voltage mathematical model, main parameters of the automatic GTAW machine and the welding power were set, then typical position free forming joints of 16Mn steel plate under 0.1~0.7 MPa were manufactured, which were classified as class A in AWS D3.6M: 1999.