优质预应力钢绞线技术装备创新集成

通过对张宣高科优质预应力钢绞线开展技术研究以及实施过程智能控制,实现了专业化、精品化生产。通过原料降缓时效技术研究,实现断丝率≤1.9次/ht;通过原料投料数据分析,量化明确二级原料投入比不得高于82.35%;冷拉拔工序采用强制润滑、高效冷却等新型技术装备,及时传导变形热量,最大限度地冷却钢丝;通过闭环水冷温控,满足了恒温控制,稳定了产品性能。

Influence of Cu content on microstructure and mechanical properties of thixoformed Al-Si-Cu-Mg alloys

The effects of Cu content on the microstructure and mechanical properties of thixoformed Al-6Si-xCu-0.3Mg(x= 3,4,5and 6,mass fraction,%) alloys were studied.The samples were thixoformed at 50%liquid content and several of the samples were treated with the T6 heat treatment.The samples were then examined by optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive X-ray(EDX) spectroscopy and X-ray diffraction(XRD) analysis,as well as hardness and tensile tests.The results show that the cooling slope casting and thixoforming process promote the formation of very fine and well distributed intermetallic compounds in the aluminium matrix and the mechanical properties of the alloys increase considerably compared with the permanent mould casting.The results also reveal that as the Cu content in the alloy increases,the hardness and tensile strength of the thixoformed alloys also increase.The ultimate tensile strength,yield strength and elongation to fracture of the thixoformed heat-treated Al-6Si-3Cu-0.3Mg alloy are 298 MPa,201 MPa and 4.5%,respectively,whereas the values of the thixoformed heat-treated alloy with high Cu content(6%) are 361 MPa,274 MPa and 1.1%,respectively.The fracture of the thixoformed Al-6Si-3Cu-0.3Mg alloy shows a dimple rupture,whereas in the alloy that contains the highest Cu content(6%),a cleavage fracture is observed.

Thermal deformation analysis of the composite material satellite antenna

Controlling the thermal deformation is a crucial index for the design of the satellite antenna. To calculate and measure the satellite antenna’s thermal deformation is also an important step for the design of satellite antenna. Based on the foundation of equivalent assumption, the thermal deformation of the parabolic satellite antenna was analyzed by the finite element method for different design project. The best design project that had the minimum of the thermal deformation could be obtained through changing the lay-angle, lay-layers and lay-thickness of each layer. Results show the asymmetry structure has the minimum of thermal deformation. This paper may provide useful information for the further investigation on the coupling of thermal-stress structure.

Number-Conserving Coherent State in Rindler Space

We introduce a kind of number-conserving coherent state in Rindler space which can describe the quantum state of thermal particles observed in Rindler space. This is based on the Unruh effect that the thermal particles seen by an accelerating observer in fiat space can be seen by an inertial observer in curved space under a conformal transformation.

Numerical Convergence of the Sinc Discrete Variable Representation for Solving Molecular Vibrational States with a Conical Intersection in Adiabatic Representation

Within the Born-Oppenheimer(BO)approximation,nuclear motions of a molecule are often envisioned to occur on an adiabatic potential energy surface(PES).However,this single PES picture should be reconsidered if a conical intersection(CI)is present,although the energy is well below the CI.The presence of the CI results in two additional terms in the nuclear Hamiltonian in the adiabatic presentation,i.e.,the diagonal BO correction(DBOC)and the geometric phase(GP),which are divergent at the CI.At the same time,there are cusps in the adiabatic PESs.Thus usually it is regarded that there is numerical difficulty in a quantum dynamics calculation for treating CI in the adiabatic representation.A popular numerical method in nuclear quantum dynamics calculations is the Sinc discrete variable representation(DVR)method.We examine the numerical accuracy of the Sinc DVR method for solving the Schrodinger equation of a two dimensional model of two electronic states with a CI in both the adiabatic and diabatic representation.The results suggest that the Sinc DVR method is capable of giving reliable results in the adiabatic representation with usual density of the grid points,without special treatment of the divergence of the DBOC and the GP.The numerical uncertainty is not worse than that after the introduction of an arbitrary vector potential for accounting the GP,whose accurate form usually is not easy to obtain.

New method for analyzing recrystallization kinetics of deformed metal by differential scanning calorimeter

The drawn copper wires have been analyzed by differential scanning calorimeter(DSC) and a new method, which uses DSC measurements to determine the Johnson-Mehl-Avrami-Kolmogorov(JMAK) exponent via introducing Arrhenius behavior and modifying the baseline of DSC curves, has been proposed. The results show that JMAK exponent and recrystallization activation energy of the drawn copper wires with a strain of 2.77 are about 2.39 and 125 k J/mol, respectively. The line linking the tangency points of DSC curve hypotenuse can be used as the baseline when calculating recrystallization fraction. The JMAK exponent obtained by the DSC method is in a good agreement with that obtained by microhardness measurements. Compared to traditional methods to measure the exponent, the proposed method is faster and less labor intensive.

Morphological Evolution of a Void under Thermal and Mechanical Loads

A model for the morphological evolution of a void under thermal and mechanical loads is established, and the thermodynamics potential of the model is given based on energy principle. Thus, the path and the bifurcation condition of the morphological evolution of the void are described, which gives some insight into the reliability of the interconnect under combined thermal and mechanical loads.