Abstract: The crystal structure of a new compound NdFeSb3 has been determined by X-ray powder
diffraction using the Rietveld method. The compound crystallizes in the orthorhombic, space group
Pbcm (No.57) with the CeNiSb3 structure type and lattice parameters a=1.26828(2)nm,
b=0.61666(2)nm, c=1.81867(4) nm, z=12 and Dcalc=7.917g/cm3.
Abstract: The DDA method parallels the finite element, which solves a finite element type of mesh
where all the elements are bounded by discontinuities. In the current studies on the DDA method, the
deformation of all the discontinuities is neglected, only the deformation of blocks is concerned with.
The actual engineering indicates that the deformation of control discontinuity is often greater than that
of block, and can not be neglected; but the deformation of the smaller discontinuities may be
neglected. In this paper, the deformation of discontinuity is studied, and the result indicates that the
displacement and stress of block element are affected by the deformation of discontinuity to a degree.
Therefore, the deformation of control discontinuity can not be neglected in the study of the DDA
Abstract: In the present paper, TiB2/Al composite with 5% volume fraction of TiB2 was fabricated by
LSM method. The effects of purification and degassing methods on TiB2/Al composite were
examined by means of X-ray diffraction (XRD) and image analysis. Hydrogen contents in the molten
composites were detected and compared among flux, inert gas and vacuum purification processes.
The experimental results indicate that under general cast condition a majority of the TiB2 particles
distribute on grain boundary, and only a few particles disperse within grains. The flux and vacuum
purifications have no virtual impact on the distribution of TiB2 and the fraction of TiB2 remains the
same after purification. However, degassing with inert gas will be detrimental; the TiB2 particles will
be separated and removed from the matrix. The hydrogen contents for flux, inert gas and vacuum
processes are 0.15ml/100g/Al, 0.12ml/100g/Al and 0.12ml/100g/Al respectively.
Abstract: A polyimide-epoxy blend has been prepared by reacting epoxy resin with imide
compounds containing carboxyl groups at the ends of the molecular. When coated on the silicon steel
sheets, the blend can be used as a kind of adhesive to bind together the silicon steel sheets of
aerospace electrical machineries. Put pressure of 0.4-0.5MPa on a stack of coated silicon steel sheets,
and cured at 200°C for 2 hours, binding course of 0.01- 0.02mm on the sheets was formed. Tensile
shear strength of the binding course on stainless steal substrate is greater than 23MPa at room
temperature, 8MPa at 200°C. After enduring in air at 300°C for 48 hours the tensile shear strength at
room temperature remained 17MPa, dipping in aerospace lubricant at 250°C for 48 hours remained
18 MPa, steeping in dimathylacetamide at 160°C for 12 hours remained 12 MPa.
Abstract: In this paper, a new low-pressure die-casting with degassing function, casting under
adjusted pressure (CAP), is proposed. The working principle of CAP process is introduced in details.
This paper focuses on the influences of moisture of compressed air on the hydrogen content within the
melt aluminum during the cyclic vacuum-pressurizing programs for CAP process. The experimental
results indicate that degassing under vacuum acts positive in refining aluminum melt. The relative
moisture of compressed air exerts a significant influence on the hydrogen content of aluminum melt.
After the melt aluminum is exposed to the air with a relative moisture of 85% for 90 min, the
hydrogen content of the melt aluminum can get to 0.4 ml/100g/Al; while under the circumstance of
CAP process, the hydrogen content is maintained between 0.05 and 0.15 ml/100g/Al depending on
the moisture capacity of the air, which virtually has no more influence on the casting qualities. Under
the condition of dry compressed air, the hydrogen content can be kept at a level as low as
0.05ml/100g/Al, which facilitates to obtain high air-tightness castings.
Abstract: The influences of Sn addition of 3%-30% on the friction and thermal expansion properties
of Al-Sn bearing alloys were investigated in this paper. The experiments were carried out on a
specially designed friction testing machine and a dilatometer. It is shown by the experiments that the
friction coefficient and hardness of the alloys decrease with the increasing of Sn content. The friction
coefficient decreases dramatically when Sn content is higher than 6%. On the other hand, the friction
coefficient is also dependent on the load. The friction coefficient increases as the load rises. The linear
CTE is also a function of temperature and Sn contents. CTE increases when the temperature rises but
has no obvious differences for the alloy system when the temperature is below 80°C. As the
temperature rises, the differences become large among the alloy system. The higher the Sn content,
the lower the CTE.
Abstract: Based on a large number of investigation and analysis for slag detection system (SDS), a
kind of automatic SDS using vibration measurements had been put forward in this paper. After
studying casting process from ladle to pouring box and protection casting supporting mechanical
structure, vibration dynamics model of supporting structure was established, also variation of steel
water impact force and influencing factors of inspecting spot vibration are analyzed. Theories of
wavelet, wavelet package and their applications in signal processing are presented. Vibration signal of
steel water was processed by the way of wavelet package, then its eigenvector and tolerance range
were obtained, and that can realize effective identification for steel water status. Experimental results
indicate that this system is very effective and achieves anticipated outcomes.
Abstract: In order to obtain the total cutting energy and the ratios of the three parts of the total energy
during cutting off the rubber, a test method was proposed and a test apparatus was constructed to
perform the rubber cutting experiment. In the test, the friction force and the cutting force were
obtained. Through the analysis of the test results, the friction work, the deformation energy, the
surface fracture energy in cutting different thickness of the rubber were calculated. This work
originally proposed a test method to acquire the friction force, the friction work between the cutter and
workpiece during punching process.
Abstract: Based on COMPASS forcefield, the relationship between microstructure and
macroscopic properties of poly (propylene-co-γ-butyrolactone carbonate) (PPCG) was firstly
investigated with ‘Materials Studio’ simulation soft successfully. The results of simulation showed
that the molecular chain of PPCG was flexible. Degradable carbonic and carboxylic ester groups
were distributed outside the PPCG cell. Furthermore the structure of micro-phase separation was
observed in PPCG cell. The structure of micro-phase separation of PPCG can be applied to the
self-assembly of drug molecule.
Abstract: Chemical components of the soil take an important role in the structure stability. It controls
the soil structure under the normal water environment such as ordinary temperature, atmospheric
pressure, and slowly changing hydro-chemical environment etc. It also has an important influence on
the ground subsidence and the formation of soil caves as well as the collapse of dispersive soil.
Scanning Electron Microscopy(SEM), CT technology and X diffraction were used to measure the
chemical damage of water to the soil structure in the laboratory. Results indicate that under normal
water environment, the change of the environmental parameters is not sufficient to cause damage to
the internal crystal force of mineral intergranulars and to activate atoms in crystal lattice, which leads
some defects and displacement of the crystal lattice. However, it can activate linking substance of
clay grains be defined as “soil mini-structure”. As the greatest contributor of soil stability, the
mini-structure is the "platform" and main place in which soil stability and instability will develop.