To fulfill the need of studying the deuterium retention in nuclear materials, the authors set up an NRA to analyze device with three channel detecting system based on 4.5 MV electrostatic accelerator in Peking University, and developed a multi-energies NRA method for quantitative depth profiling deuterium. With the simultaneous energy spectra of p and 4He created by the D (3He, p) 4He nuclear reaction, by adopting several different incident 3He+ energies (0.8?3.6 MeV), a reasonable better depth resolution and higher sensitivity in a larger analyzing depth could be obtained. The authors also measured differential cross-section of the 3He-D reaction at 135°. The relative accuracy of these data was better than ±3.9%. The initial measurement of concentration and depth profiles of D was carried out, using targets of implanted PC-W samples, as well as CMSIIW samples from a W-coated outer divertor tile of TOKAMAK AUG near the strike points. A ~6 μm analyzed depth could be obtained with a depth resolution less than 1.5 μm throughout the whole detecting range and a ~20 nm minimal resolution at the sample surfaces. The detection limit was around 5×1019 D/m2. Apart from the statistical and fitting error of NRA spectra, the NRA system had an experimental error of ±7.5% from the parameter measurement.

Recent developments in modeling of clearance joints and dynamics of mechanical systems with clearances are reviewed. Different modeling approaches for clearance joints are summarized firstly, which comprise the massless link approach, the non-smooth dynamics approach, the contact force approach and the 3D revolute joint approach. Then, applications of these approaches in the study of the nonlinear dynamics, and performance and reliability evaluation of the mechanical systems with clearances are systematically reviewed. Finally, the key problems and priorities which need to be further studied are proposed, including the modeling of clearace joints considering stick-slip phenomenon, contact surface profile and conformal contact condition, the dynamic analysis and kinematic accuracy evaluation of mechanical systems with both clearances and uncertainties, and the design for clearance joints.

The authors adopt molecular dynamics simulations to get a basic physical image of the tungsten ablation phenomenon induced by intense pulsed ions irradiation. A one-dimension heat transfer model is set up and a series of simulations with different pulse energy fluences are applied. Ablation threshold and ablation depth are calculated and compared with thermal dynamic theoretical values. Energy allocation condition of the simulation system are discussed, which depends on whether the pulse energy exceed ablation threshold. Based on the calculation results, the authors drew a preliminary profile of tungsten ablation under a transient high heat flux brought by energetic ions.

Thermal response of pure and two kinds of oxide dispersion strengthened tungsten alloys were investigated using intense pulsed ion beam (IPIB) device. Scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX) were used to examine the surface modifications and the distributions of dispersion elements. By comparing the results, it is found that pure tungsten show a better resistance to thermal shock. From the perspective of the tolerance of heat load, WL10 and WYT are not recommended for PFMs.

Two-dimensional micro-hole lattice arrays with specified structure parameters were fabricated on LiNbO₃ (LN) substrateby means of focused ion beam (FIB) etching, and the influence of etching parameters, such as spot current, etching time full rate, were investaged. In order to etch good quality holes, the authors used gas-assisted etching (GAE) with focused ion beam. The results show that GAE can reduce the effect of redeposition and obtain better hole profile compared with FIB etching. According to simulative calculation, the photonic bandgap of lattice array, etched by GAE with XeF₂, is more close to the ideal photonic bandgap.

The intense pulsed ion beam (IPIB) mixing effect of Ni/Ti and Al/Ti systems are studied. Compared with common ion beam, it is obvious that the mixing layers formed by IPIB irradiation are thicker, and the mixing rate is much higher. However, the IPIB mixing effects are various for different film/substrate systems because of their different thermodynamic properties. During IPIB irradiation, film material lost seriously, especially for the samples with big differences in their film and substrate thermal dynamic parameters. Two IPIB mixing mechanisms which are distinct from common ion beam mixing are discussed and the reason of mass loss of film materials are analyzed.