Metal-organic frameworks (MOFs) have attracted great attention because of their intriguing molecular topologies and potential applications in chemical separation, [1] gas storage, [2] drug delivery, [3] catalysis [4] and chemical sensor technology. [5] Particularly, MOFs could also be potential energetic materials because of their high densities and high heats of detonation. For example, Hope-Weeks and co-workers recently reported two hydrazine-perchlorate 1D MOFs [(Ni(NH 2 NH 2 ) 5 (ClO 4 ) 2 ) n (NHP), and (Co(NH 2 NH 2 ) 5 (ClO 4 ) 2 ) n (CHP)] with linear polymeric structures, [6] which were regarded as possibly the most powerful metal-based energetic materials known to date, with heats of detonation comparable with that of hexanitrohexaazaisowutzitane (CL-20; about 1.5 kcal g À1 ).Unfortunately, these coordination polymers were highly sensitive to impact deriving from their low rigidity characteristic of such linear polymeric structures, which makes practical use infeasible. In order to decrease the sensitivities, the same authors also used a hydrazine derivative (hydrazine-carboxylate) as the ligand to construct MOFs with 2D sheet structures [((

Non-negative Matrix Factorization (NMF) is a part-based image representation method which adds a non-negativity constraint to matrix factorization. NMF is compatible with the intuitive notion of combining parts to form a whole face. In this paper, we propose a framework of face recognition by adding NMF constraint and classifier constraints to matrix factorization to get both intuitive features and good recognition results. Based on the framework, we present two novel subspace methods: Fisher Non-negative Matrix Factorization (FNMF) and PCA Non-negative Matrix Factorization (PNMF). FNMF adds both the non-negative constraint and the Fisher constraint to matrix factorization. The Fisher constraint maximizes the between-class scatter and minimizes the within-class scatter of face samples. Subsequently, FNMF improves the capability of face recognition. PNMF adds the non-negative constraint and characteristics of PCA, such as maximizing the variance of output coordinates, orthogonal bases, etc. to matrix factorization. Therefore, we can get intuitive features and desirable PCA characteristics. Our experiments show that FNMF and PNMF achieve better face recognition performance than NMF and Local NMF.

Metal-organic frameworks (MOFs) have attracted great attention because of their intriguing molecular topologies and potential applications in chemical separation, [1] gas storage, [2] drug delivery, [3] catalysis [4] and chemical sensor technology. [5] Particularly, MOFs could also be potential energetic materials because of their high densities and high heats of detonation. For example, Hope-Weeks and co-workers recently reported two hydrazine-perchlorate 1D MOFs [(Ni(NH 2 NH 2 ) 5 (ClO 4 ) 2 ) n (NHP), and (Co(NH 2 NH 2 ) 5 (ClO 4 ) 2 ) n (CHP)] with linear polymeric structures, [6] which were regarded as possibly the most powerful metal-based energetic materials known to date, with heats of detonation comparable with that of hexanitrohexaazaisowutzitane (CL-20; about 1.5 kcal g À1 ).Unfortunately, these coordination polymers were highly sensitive to impact deriving from their low rigidity characteristic of such linear polymeric structures, which makes practical use infeasible. In order to decrease the sensitivities, the same authors also used a hydrazine derivative (hydrazine-carboxylate) as the ligand to construct MOFs with 2D sheet structures [((

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A series of trinitromethyl/trinitroethyl substituted derivatives of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo[5,5,0, 0(3.11),0(5.9)] dodecane (CL-20) were designed and investigated by theoretical methods. Intramolecular interactions between the trinitromethyl/trinitroethyl and the cage were investigated. The effects of trinitromethyl/trinitroethyl groups on stability of the parent compound are discussed. The results reveal a mutual influence of bond length and dihedral angle between the trinitromethyl and the cage. Compared to CL-20, the sensitivity of derivatives is barely affected. Properties such as density, heat of formation and detonation performance of these novel compounds were also predicted. The introduction of the trinitromethyl group can significantly enhance the oxygen balance, density and detonation properties of the parent compound. The remarkable energy properties make these novel cage compounds competitive high energy density materials.