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61.
报道了用高效液用色谱法同时测定食用植物油中的抗氧剂叔丁基对羟基茴香醚(BHA)和2,6-二叔丁基对甲酚(BHT)的实验方法。采用ZorbaxODSC_(18)色谱住,甲醇:水(90:10,V/V)作流动相,检测波长为245nm,流速为1mL/min。检测下限分别为15ng(BHA),90ng(BHT),回收率分别是96.8%±9.8%(BHA),99.0%±3.2%(BHT)。方法快速、准确,灵敏度高。  相似文献   
62.
This Letter shows explicitly that the descent sequence of cocycles in a gauge group realizes the ech-de Rham double complex. Meanwhile the ech complex corresponds to finite gauge transformations. This Letter also shows how the indices of each order of cocycles characterizes the obstructions on overlapping spheres in different dimensions and how these indices are equal to a common one.  相似文献   
63.
Hou H  Li L  Li G  Fan Y  Zhu Y 《Inorganic chemistry》2003,42(11):3501-3508
Using FcCOONa (Fc = (eta(5)-C(5)H(5))Fe(eta(5)-C(5)H(4))) as starting material, we obtained an unprecedented metal-organic coordination polymer containing ferrocenecarboxylate components [[Pb(2)(FcCOO)(eta(2)-FcCOO)(mu(2)-eta(2)-FcCOO)(mu(3)-eta(2)-FcCOO)(CH(3)OH)].1.5CH(3)OH.H(2)O](n) (1), tetramer [Zn(4)(mu(2)-FcCOO)(6)(mu(4)-O)] (2), and coordination polymers [Pb(FcCOO)(mu(2)-FcCOO)(bpe)](n) (3) (bpe = 1,2-bis(4-pyridyl)ethene), [[Zn(FcCOO)(2)(bpt)].2.5H(2)O](n) (4) (bpt = N,N'-bis(3-pyridylmethyl)thiourea), and [Zn(FcCOO)(eta(2)-FcCOO)(bbp)](n) (5) (bbp = 4,4'-trimethylene-dipyridine). Compounds 1 and 2 are formed by ferrocenecarboxylate units coordinating with Pb(II) or Zn(II). In polymer 1, ferrocenecarboxylate units have four kinds of coordinate modes; just these novel coordinate modes lead to the unprecedented one-dimensional polymer where two kinds of rhomboids are arranged alternatively along the chain. Compound 2 is a tetramer, in which a distinct connectivity of the six ferrocene units is established through the four Zn atoms. Compounds 3-5 are obtained by organic ligands bridging Pb(II) or Zn(II), leading to a new type of metal-organic coordination polymer.  相似文献   
64.
本文对九种芳香单酮(苯乙酮、对氯苯乙酮、对甲氧基苯乙酮、对氨基苯乙酮、对硝基苯乙酮、间硝基苯乙酮、2.4-二甲基苯乙酮、1-萘乙酮和1-萘基苯基甲酮)在丙酮溶液中的吸收光谱进行了比较。发现芳香单酮在溶液中的分散是不均匀的, 随浓度增加, 有芳香单酮的聚集体生成。且芳香单酮分子的共轭体系越发达或苯环上电子云密度越犬, 分子就越易聚集。同时提出芳香单酮聚粲时的分子排列是苯环对苯环“面对面”取向的推断。  相似文献   
65.
The reaction of [NH4]2[MO2S2], AgI and (n-Bu)4NBr in solid state produced the polyoxometalates [(n-Bu)4N]4[M6O19][Ag2I4] (1, M? Mo; 2, M? W) which were structurally determined. The crystals of 1 and 2 are isomorphous, monoclinic, space group P21/c. 1, a = l.6624(2), b=1.6699(3), c=l.7217(2) nm, β=98.29(1)°, V=4.729(1) nm3, Z=2, R=0.040, Rw“0.037; 2, a = 1.6636(3), b = 1.6733(3), c = 1.7190(3) nm, β=98.25(1)°, V=4.736(l) nm3, Z = 2, R = 0.038, Rw = 0.047. The results of the structure determination showed that the two compounds had the same structures whose skeletons are composed of [Ag2I4]2. and [M6O19]2-. The difference of them and heteropolymetalate compounds synthesized in solution is that the title compounds contain cluster. ion, heteropolymetalate and organic cations, while the latter is only composed of heteropolymetalate and organic cations.  相似文献   
66.
Novel 2-(3-trifluoromethylphenoxy)-4-trifluoromethylthiazole-5-carboxamides were designed and synthesized utilizing ethyl 3-amino-4,4,4-trifluoro-2-butenoate as a starting material via six steps. Subsequently, their biological activities were evaluated in the greenhouse. Results indicated that several compounds have some insecticidal or fungicidal activity at 600 g ai/ha and 300 g ai/ha, respectively.  相似文献   
67.
Unicyclic Graphs with Minimal Energy   总被引:7,自引:0,他引:7  
If G is a graph and 1,2,..., n are its eigenvalues, then the energy of G is defined as E(G)=|1|+|2|++| n |. Let S n 3 be the graph obtained from the star graph with n vertices by adding an edge. In this paper we prove that S n 3 is the unique minimal energy graph among all unicyclic graphs with n vertices (n6).  相似文献   
68.
K助化Co—Mo/Al2O3催化剂的表征   总被引:1,自引:0,他引:1  
  相似文献   
69.
70.
A procedure for the Raman spectra calculation of vitreous and molten silicates was presented in this paper. It includes molecular dynamics MD simulation for the generation of equilibrium configurations, Wilson's GF matrix method for the calculations of eigenfrequencies and corresponding vectors, electro-optical parameters method (EOPM) for the Raman intensity calculations, and the bond polarizability model (BPM) for the determination of polarizability and polarizability derivative. One of the most important characteristics of this procedure is the achievement of the partial Raman spectra of five tetrahedral units, as well as the total spectral envelope. In this paper, the calculation was carried out for the vitreous and molten calcium silicates with different compositions and at various temperatures. It is worthwhile to note that the calculation is based on statistical configurations distribution in the space and so it is not needed to artificially adjust the full width at half maximum (FWHM) of spectra. It was also tested through the good agreement of the calculated spectra with the experimental, including some regularity of spectral properties. According to the calculation, the symmetrical stretching of whole tetrahedral units, to which the stretching of Si-O(nb) bond gives the main contribution to intensity, is proven to be the dominance in the high-frequency range (800-1200 cm(-1)) and the symmetrical bending of Si-O(b)-Si, to which the stretching of Si-O(b) bond exhibits the main contribution, is the dominance in the medium-frequency range (400-700 cm(-1)). As the first theoretical results, the Raman scattering coefficient of each Q(i) was found little change along with the variation of composition and temperature.  相似文献   
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