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The Microstructural Evolution in HMX Based Plastic-bonded Explosive During Heating and Cooling Process: an in situ Small-angle Scattering Study

Yan G., Tian Q., Liu J., Fan Z., Sun G., Zhang C., Wang Y., Chen B., Gong J., Zhou X., Yang Z., Nie F., Li J., Li X.

Central European Journal of Energetic Materials

2016

Vol. 13, no. 4

916--926

The thermal damage in octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) based plastic-bonded explosive (PBX) was investigated using in situ small-angle neutron and X-ray scattering techniques. The microstructural evolution was quantitatively characterized by the model fitting parameters of total interfacial surface area (Sv) and void volume distribution. The Sv of HMX-PBX decreased markedly above 100 °C, indicating the movement of binder into the voids. After subsequent cooling to room temperature, the scattering intensity increased significantly with increasing storage time, and a new population of voids with average diameter of 20 nm was observed, accompanied by the gradual phase transition of HMX from δ- to β-phase. The experimental results implied that serious damage within the HMX-PBX was developed during storage after heating.

Polarity-reversed ultra-wideband monocycle pulse generation with dual-channel multicasting in a photonic crystal fiber

Gong J, Hui Z

Optica Applicata

2015

Vol. 45, nr 1

25--39

This paper proposes and demonstrates a novel scheme of a two-channel-output ultra-wideband monocycle pulse generator consisting of a 100 m dispersion-flattened highly nonlinear photonic crystal fiber and two optical bandpass filters. Based on the cross-phase modulation effect in a dispersion-flattened highly nonlinear photonic crystal fiber, two polarity-reversed ultra-wideband monocycle pulses simultaneously output from two different channels are successfully achieved by appropriately locating the probe wavelength at the left linear slope and the right linear slope of the two optical bandpass filters transmission spectra, respectively. The full width at half-maximum and a fractional bandwidth of 24 ps and 260% for a positive pulse, 24 ps and 251% for a negative pulse are obtained. Moreover, the influences of input signal powers, the polarization misalignment between the data light and the continuous wave probe light, and probe wavelength variation on the double output ultra-wideband signals quality are also investigated. The results show that the system has some tolerance to both the input signal power fluctuation and the slight polarization mismatch and even can efficiently operate with a widely tunable wavelength range. This makes it very attractive for engineering applications in future multiuser ultra-wideband-over-fiber communication systems.

Three-Level Adapted Output Space Mapping Technique for Two-Objective Optimization

Gong J., Ben-Ayed R., Gillon F., Brisset S., Brochet P.

Przegląd Elektrotechniczny

2012

R. 88, nr 7b

65-68

Multi-objective optimization with 3D finite element model is a complex and time consuming process. Output space-mapping techniques allow having an affordable computation cost with a minimum number of computationally expensive FEM evaluations. In this paper, a three-level adapted output space-mapping technique is proposed to assist two-objective optimization problems. Three models having different granularity and describing the same device are used jointly in the optimization process. The results for the safety isolating transformer show that the proposed algorithm allows saving a substantial amount of computation time compared to the classical two-level output space-mapping technique.

Przedmiotem artykułu jest dwukryterialna optymalizacja, trójpoziomowa, wykorzystująca metody odwzorowania zewnętrznej przestrzeni. Przypadek techniczny (transformator bezpieczeństwa) przeanalizowano trzema metodami, różniącymi się od siebie ziarnistością. Wyniki analizy wskazały na istotną redukcję czasu obliczeń w porównaniu do podejścia klasycznego dwupoziomowego.