An improved fusion algorithm for infrared and visible images based on multi-scale transform

In this paper, an improved fusion algorithm for infrared and visible images based on multi-scale transform is proposed. First of all, Morphology-Hat transform is used for an infrared image and a visible image separately. Then two images were decomposed into high-frequency and low-frequency images by contourlet transform (CT). The fusion strategy of high-frequency images is based on mean gradient and the fusion strategy of low-frequency images is based on Principal Component Analysis (PCA). Finally, the final fused image is obtained by using the inverse contourlet transform (ICT). The experiments and results demonstrate that the proposed method can significantly improve image fusion performance, accomplish notable target information and high contrast and preserve rich details information at the same time.     

Band gap modulation of transition-metal dichalcogenide MX2 nanosheets by in-plane strain

The electronic properties of quasi-two-dimensional honeycomb structures of MX₂ nanosheets (M=Mo, W and X=S, Se) subjected to in-plane biaxial strain have been investigated using first-principles calculations. We demonstrate that the band gap of MX₂ nanosheets can be widely tuned by applying tensile or compressive strain, and these ultrathin materials undergo a universal reversible semiconductor-metal transition at a critical strain. Compared to WX₂, MoX₂ need a smaller critical tensile strain for the band gap close, and MSe₂ need a smaller critical compressive strain than MS₂. Taking bilayer MoS₂ as an example, the variation of the band structures was studied and the semiconductor-metal transition involves a slightly different physical mechanism between tensile and compressive strain. The ability to tune the band gap of MX₂ nanosheets in a controlled fashion over a wide range of energy opens up the possibility for its usage in a range of application.     

Enhanced photocatalytic degradation of rhodamine B under visible light irradiation on mesoporous anatase TiO2 microspheres by codoping with W and N

Mesoporous anatase TiO₂ microspheres were prepared via solvothermal method. Ammonium tungstate was used as the W source, and ammonia gas flowing in an ammonothermal reactor as the N source for codoping. TiO₂:(W,N) mesoporous microspheres, which were prepared from solvothermal treatment at 160 °C for 16 h and thermal ammonolysis at 500 °C for 2 h after calcination, have high specific surface area of 106 m² g⁻¹. XPS results indicate the presence of N_O, N_i and W⁶⁺ in the codoped mesoporous TiO₂ microspheres. Monodoping with N shifts the absorption band edge of anatase TiO₂ from ultraviolet region to visible region. Although codoping with W makes the visible light absorbance decrease a little, the photocatalytic degradation of a cationic dye rhodamine B (RhB) on mesoporous TiO₂:(W,N) microspheres is increased to 1.7 times of that on mesoporous TiO₂:N microspheres. This may due to decreasing recombination centers by W-doping charge compensation.     

A general method for preparing lanthanide oxide nanoparticles via thermal decomposition of lanthanide(III) complexes with 1-hydroxy-2-naphthoic acid and hydrazine ligands

Six new lanthanide(III) complexes (i.e., [Ln(L)₂(NA)_1.5]·3H₂O, where Ln=La(III), Pr(III), Nd(III), Sm(III), Gd(III), and Ce(III) and L and NA indicate N₂H₄ and C₁₀H₆(1-O)(2-COO), respectively) with 1-hydroxy-2-naphthoic acid [C₁₀H₆(1-O)(2-COOH)] and hydrazine (N₂H₄) as co-ligands were characterized by elemental, FTIR, UV-visible, and XRD techniques. In the FT-IR spectra, the N-N stretching frequency in the range of 981–949 cm⁻¹ demonstrates evidence of the presence of coordinated N₂H₄, indicating the bidentate bridging nature of hydrazine in the complexes. These complexes show symmetric and asymmetric COO⁻ stretching from 1444 to 1441 cm⁻¹ and 1582 to 1557 cm⁻¹, respectively, indicating bidentate coordination. TG-DTA studies revealed that the compounds underwent endothermic dehydration from 98 to 110 °C. This was followed by the exothermic decomposition of oxalate intermediates to yield the respective metal oxides as the end products. From SEM images, the average size of the metal oxide particles prepared by thermal decomposition of the complexes was determined to be 39–42 nm. The powder X-ray and SEM coupled with energy dispersive X-ray (EDX) studies revealed the presence of the respective nano-sized metal oxides. The kinetic parameters of the decomposition of the complexes were calculated using the Coats-Redfern equation.     

The novel sandwich-type heteropolyoxotungstates [M2Bi2(beta-B-MW9O34)2]14- (M = Co(II), Zn(II)): beta-type dimeric heteropolyanions with a transition metal as the central heteroatom and Bi(III) and M as linking atoms

Two new sandwich-type heteropolyoxometalates, Na(14)[Co(2)Bi(2)(beta-B-CoW(9)O(34))(2)].48H(2)O (1) and Na(14)[beta-B-Zn(2)Bi(2)(ZnW(9)O(34))(2)].51H(2)O (2), have been synthesized at pH = 7.5-8 and characterized by elemental analysis, IR, UV-vis, TG-DSC and electrochemistry. Structural analysis indicates that both polyanions, M(2)Bi(2)(beta-B-MW(9)O(34))(2)](14-) (M = Co(II) and Zn(II)), are isomorphic and consist of two unprecedented [beta-B-MW(9)O(34)](12-) subunits linked by two M(II) and two Bi(III) which are coplanar. The polyanions are also the first examples of dimeric heteropolyanions with Bi(III) only as the second (linking) heteroatom and the transition metals (Co(II) or Zn(II)) as the first and second heteroatoms as well. The lower absorption of nu(W-O(d)) (915 cm(-1)) in the IR is a simple and feasible judgment of sandwich-type polyanions with a transition metal ion as a central heteroatom.     

Research on the chelation between quercetin and Cr(III) ion by Density Functional Theory (DFT) method

In order to locate the exact chelation site, the chelation between quercetin and Cr(III) ion is studied using the theoretical methods. Many different potential complexes, formed with natural and deprotonated quercetin chelating bare and hydrated Cr(III) ion, respectively, are studied by using Density Functional Theory method. Both total and binding energies are calculated. The results from the studies indicate that Cr(III) ion is affine in forming a complex with quercetin at the 5-hydroxy-4-keto site and that deprotonated quercetin has stronger chelating power than natural quercetin. Apart from the theoretical studies, the experiments are performed to modify the theoretical conclusions. Meanwhile, quercetin–Cr(III) complex has been synthesized, and the chelation site is analyzed using IR spectroscopy and UV/vis spectrum. The experimental results are found to have the same conclusions as those by theoretical studies.     

Two New Nitrone Alkaloids from Huperzia serrata

Two new nitrone alkaloids were isolated from the whole plant of Huperzia serrata (Thunb .) Trev . They are both phlegmarine‐type lycopodium alkaloids with a nitrone moiety. Their structures were elucidated on the basis of spectral evidences, and their configurations were established on the basis of optical rotation, CD, and NOESY‐NMR data.     

An unusual asymmetric polyoxomolybdate containing mixed-valence antimony and its derivatives: [Sb4VSb2IIIMo18O73(H2O)2]12- and {M(H2O)2[Sb4VSb2IIIMo18O73(H2O)2]2}22- (M = MnII, FeII, CuII or CoII)

A new type of heteropolyanion containing mixed-valence antimony, [Sb4(V)Sb2(III)Mo18O73(H2O)2](12-) (1a), and its four derivatives, {M(H2O)2[Sb4(V)Sb2(III)Mo18O73(H2O)2]2}(22-) (M = Mn(II), Fe(II), Cu(II), or Co(II)) (2a-5a), have been isolated as ammonium salt, and their structures were determined by single-crystal X-ray diffraction. The framework of the polyanion 1a displays a curious asymmetric structure, and there exist six types of Sb coordination environments and seven types of {MoO6} octahedra. The title compounds were also characterized by elemental analyses, IR, UV-vis, Raman spectra, and cyclic voltammogramms.     

2,6-二氨基-3,5-二硝基吡嗪-1-氧化物(LLM-105)晶体结构、安全性及密度泛函理论研究

利用DMSO和水的混合溶剂培养出2,6-二氨基-3,5-二硝基吡嗪-1-氧化物(LLM-105)的单晶,晶体属单斜晶系,空间群为Pna2(1)。运用Dmol3中的密度泛函理论计算了LLM-105的晶体性质,态密度计算表明C-N 为该物质的热解引发键。通过设计等键反应预测得到LLM-105的生成热(HOF),结合HOF与晶体密度利用 Kamlet-Jacobs公式得到该物质的爆速、爆压;键断裂能的计算结果表明 C-NO2为热解引发键。运用微热量仪对其进行比热容测定,由比热容与温度的关系式及LLM-105的热分解参数得到了该化合物从开始分解到爆炸所需的时间即绝热至爆时间。     

方波伏安法未标记测定天然蛋白质材料丝素蛋白

首次采用循环伏安法和方波伏安法在0.01 mol/L HCl溶液中考察丝素蛋白的电化学行为。在0-1.2V的电位扫描范围内,在0.2V/s的扫速下,丝素蛋白有两个分别位于0.91V和0.43V的氧化峰Pa, 1和Pa,2,一个位于0.24V的还原峰(vs.SCE）Pc。峰Pa, 1的峰电流与丝素蛋白的浓度在5.8×10-8 ~1.1×10-6 mol/L范围成正比,检测限为3.0×10-8 mol/L (S/N=3)。本方法选择性高,共存物质如另一种天然蛋白质丝胶和其他小分子物质并不干扰测定。本方法不经过预分离和预纯化就可直接用来测定生丝液体样品中丝素蛋白含量。