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71.
Due to the difficulty in synthesizing perhalogenated metallophthalocyanine, the method of ammonium molybdate solid phase catalysis was introduced, and by using tetrachlorophthalic anhydride and urea as the raw materials, hexadecachloro zinc phthalocyanine (ZnPcCl16) was synthesized. Components of the composite were analyzed by energy spectrum, and its functional group structures and absorption peaks were characterized by IR and UV-vis spectroscopy. The thin films of gas sensors were prepared in a vacuum evaporation system and evaporated onto SiO2 substrates, where sensing electrodes were made by MEMS micromachining. The optimal conditions for the films are: substrate temperature of 150 ℃ evaporation current of 95 A and film thickness of 50 nm. The result showed that the sensors were ideally sensitive to Cl2 gas and could detect the minimum concentration of 0.3 ppm. 相似文献
72.
73.
74.
在溶剂热条件下,以含卤素有机羧酸3-溴-吡啶-2,6-二甲酸(H2L)为配体,以硝酸钴、硝酸铜为金属源,合成了两例配合物:[Co(L′)3](1)和[Cu(L′)2]n(2)(HL′=5-溴-吡啶-2-甲酸),通过元素分析(EA)、X射线单晶衍射(SXRD)、X射线粉末衍射(PXRD)、红外光谱(IR)和热重分析(TGA)进行结构表征。X射线单晶衍射结果表明,配体H2L在反应过程中发生脱羧现象,生成单羧酸配体5-溴-吡啶-2-甲酸。在配合物1中,每个Co(Ⅲ)都位于略微扭曲的八面体几何构型中,不对称单元中含有两个单核单元,单核单元通过C—H…O氢键形成三维超分子结构。配合物2的不对称单元中含有一个Cu(Ⅱ),两个脱质子的L′-配体,每个Cu(Ⅱ)都是六配位的,位于扭曲的八面体几何构型中。Cu(Ⅱ)由配体连接生成1D链结构,通过C—H…O氢键形成三维超分子结构。此外,研究了两例配合物的热稳定性能。 相似文献
75.
Recep Korkmaz 《Semigroup Forum》2009,78(3):528-535
In this paper we study dense inverse subsemigroups of topological inverse semigroups. We construct a topological inverse semigroup
from a semilattice. Finally, we give two examples of the closure of B
( −∞, ∞ )1, a topological inverse semigroup obtained by starting with the real numbers as a semilattice with the operation a
∨
b=sup{a,b}.
The author would like to thank to the referee for useful suggestions. 相似文献
76.
The production of the three normal neutrinos via e-e+ collision at Z-boson peak (neutrino production in a Z-factory) is investigated thoroughly. The differences of ve-pair production from vμ-pair and vτ-pair production are presented in various aspects. Namely the total cross sections, relevant differential cross sections and the forward-backward asymmetry etc. for these neutrinos are presented in terms of figures as well as numerical tables. The restriction on the room for the mixing of the three species of light neutrinos with possible externals (heavy neutral leptons and/or sterile neutrinos) from refined measurements of the invisible width of Z-boson is discussed. 相似文献
77.
78.
The chemical polymerization method is very convenient for obtaining a plurality of the polymer. Chemical synthesizes of polypyrrole (PPy) were performed in acetonitrile solutions containing different dopants: dodecylbenzene sulphonic acid (DBSA), tetrafluoroborate (BF4 ?), perchlorate (ClO4 ?) and oxalate (C2O4 2?). These polymers were characterized by using scanning electron microscopy (SEM), ultraviolet–visible (UV–Vis) spectrophotometer, Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD) techniques and dry conducting measurement. It was observed that the interactions between the polymers and dopant materials are completely different from each other. As a result of this interaction, the conductivities and crystal structures of PPy are also different from each other. Results in this work showed that the dopants used affected both electrical conductivities and crystal structures of PPy. 相似文献
79.
This paper proposes a narrowband interference (NBI) suppression algorithm for Direct Sequence-Code Division Multiple Access systems. The NBI is considered from heterogeneous networks, and predicted based on its cyclostationary characteristic using a nonlinear feed-forward neural network predictor which eliminates the nonlinearity of the spread spectrum (SS) signal in the NBI prediction. To further improve the suppression performance, this paper exploits the structure of the spreading code, and proposes an iterative code-aided algorithm to jointly estimate the NBI and the SS signal. Simulation results reveal that the proposed algorithm largely outperforms the conventional linear prediction filtering and linear-conjugate linear polyperiodically time-varying filtering methods in both the signal to interference plus noise ratio improvement and the bit error rates, when it operates in NBI-contaminated environments. 相似文献
80.
Yan Y Liu Q Wang J Wei J Gao Z Mann T Li Z He Y Zhang M Liu L 《Journal of colloid and interface science》2012,371(1):15-19
A novel single-step approach was developed to prepare large-scale MgAl-LDHs ultrathin nanosheets. The key point of the successful realization was that we employed a high concentration of H(2)O(2). Oxygen molecules, derived from in situ decomposition of H(2)O(2), were speculated to be the decisive factor leading to complete separation of LDHs layers. The ultrathin nanosheets were characterized by XRD, TEM, AFM, FT-IR, and TG-DSC. The results indicated that the thickness of these nanosheets was about 1.44 nm, which was almost in perfect agreement with the theoretical thickness of two LDHs layers. From the TG-DSC curves, the weight loss of these exfoliated MgAl-LDHs ultrathin nanosheets at 500°C was 18.5%, which was much smaller compared to the 32.3% weight loss of unexfoliated MgAl-LDHs. 相似文献