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141.
分子拓扑指数在晶格能中的应用凌天才(重庆师范学院化学系重庆630047)关键词拓扑指数,晶格能分子拓扑指数实际上是分子图的不变量。自wiener ̄[1]于1947年首次提出wiener指数并用以关联烃类的沸点等数据以来,分子拓扑指数广泛用于关联与预测... 相似文献
142.
The paper presents the results of testing
the thermal stability and flammability of butadiene-acrylonitrile rubber vulcanizates
with different contents of combined acrylonitrile: Perbunan NT 1845 and Perbunan
NT 3945 from Bayer, containing unmodified and bromine- or iodine-modified
silica. The test results were obtained with the use of a derivatograph, measurements
of flammability by the method of oxygen index, in air and also with the use
of a cone calorimeter. The effect of the modification on the zeta potential
was also examined.
A considerable reduction in the flammability
of nitrile rubber vulcanizates filled with silica can be obtained by the modification
of filler with bromine or iodine. All the vulcanizates containing modified
silica are self-extinguishing. An appropriate filling of NBR 39 vulcanizates
with bromine-modified silica makes it possible to obtain non-flammable polymeric
materials. They neither ignite nor glow under the action of a flame source
for 30 s.
The findings can be a rational basis for the synthesis
of modified silica that can act as active filler and effective flame-retardant
agent at the same time. 相似文献
143.
Alexander Scheeline Bernita Williams Eric Williksen Jeffrey Steinfeld Brian McEnroe 《Spectrochimica Acta Part B: Atomic Spectroscopy》1998,53(14):1855-1861
This article is an electronic publication in Spectrochimica Acta Electronica (SAE), a section of Spectrochimica Acta, Part B (SAB). The hardcopy text is accompanied by an electronic archive, stored on the SAE homepage at http://www.elsevier.nl/locate/sabe. The archive contains data, index and program files. The main article discusses the bibliographical purpose of the program and data files. A collective index for Spectrochimica Acta for volumes since it was split into Parts A and B, and continuing through 1991 for SAA and 1997 for SAB, is presented in DBF format, along with rudimentary data entry and access software. 相似文献
144.
145.
A homologous series of 2,4-dichlorobenzyl alkyl ethers (DCBEs) have been synthesized and purified for use as retention index calibrants and internal standards. They are stable, sensitive to ECD and FID and ideal for GC-MS, with base peaks at m/z 159/161. The retention index calibration against the n-alkanes for a linear temperature program (LTP) series is given and recommendations made for the most suitable members of the DCBE series for use as internal standards in organochlorine (OC) residue analysis. 相似文献
146.
固固相反应合成牛磺酸水杨醛钾与锑、铋的配合物 总被引:2,自引:0,他引:2
合成了牛磺酸水杨醛钾,并采用室温固固相反应法合成了牛磺酸水杨醛钾与三氯化锑和三氯化铋的配合物,其组成为:K2MC18H20O8N2S2 (M = Sb, Bi)。两种配合物的晶体结构均属于单斜晶系,锑配合物的晶胞参数为:a = 1.2869 nm, b = 1.7636 nm, c = 1.9917 nm, β= 93.79埃活榕浜衔锏木О问篴 = 1.4770 nm, b = 2.0334 nm, c = 2.0149 nm, β= 94.05。红外光谱表明N、Cl原子参与了配位,中心离子的配位数为5。 相似文献
147.
Summary Reproducibility of the Kovats retention indices of alkylbenzenes was studied on conventional “PONA” fused-silica capillary
columns coated with crosslinked dimethyl silicone phase, with a film thickness of 0.5 μm. The data were compared with those
obtained on conventional OV-101 columns. The tested PONA columns showed reproducible chromatographic properties, capacity
ratios and high efficiencies. Having a standard deviation of s=0.03 i.u. of the retention indices on a single column, the
column-to-columns differences were found to be up to 0.3 i.u. Higher indices were determined for crosslinked columns, the
difference being in most cases about one i.u. 相似文献
148.
Our two original approaches, the first based on the topological (connectivity) index 3χv and the second based on the model of overlapping spheres (OS), were applied for the estimation of stability constants of copper(II) complexes (CuL) with ethylenediamines (N = 14) and diethylenetriamines (N = 8), and mixed complexes (CuLA) of amino acids and diethylenetriamines (N = 18). The stability constants of the ethylenediamine complexes were predicted “indirectly” from calibration models developed on diethylenetriamines and vice versa, and also by a more direct method using the leave-one-out procedure of cross validation (cv). By averaging all the estimates, stability constants were reproduced with a rms error of 0.56 and 0.43 log K units for diethylenetriamines and ethylenediamines, respectively. 相似文献
149.
从充分利用气相色谱/质谱(GC/MS)提供的信息来鉴定GC流出组分的目的出发,并以脂肪醇分析为例讨论了GC保留指数在MS谱图解析及MS鉴定结果的合理性检验方面的作用。总结了GC保留的同系物规律、极性规律、加和规律及异构物规律来指导MS谱图解析。提出了含氧化合物官能团相对于-CH2-质量数的保留指数附加贡献值辅助MS确定化合物的类别。同时采用了GC/MS中选择离子检测方法(SIM)在分子离子峰受噪音干扰或太弱以至完全未观测到时来进一步佐证其相对分子质量。 相似文献
150.
Comparison
of the fragility index of different eudragit polymers determined by activation
enthalpies
Gabriella Csóka A. Gelencsér Dorottya Kiss Eszter Pásztor I. Klebovich Romána Zelkó 《Journal of Thermal Analysis and Calorimetry》2007,87(2):469-473
The present study aimed to apply fragility
index (m) of polymers in the determination
of the optimal amount of plasticizer in polymer films. The fragility index
of different Eudragit polymers (RS, RL, EPO) was assessed by differential
scanning calorimerty (DSC), applying the Arrhenius connection (logq–1/T
g).
The fragility of Eudragit EPO films proved to be the highest, while in the
case of RS and RL, the increase of the alkyl-chain length caused the increase
of fragility. Studying the effect of plasticizer (triethyl citrate, TEC) on
the m value of Eudragit RL and RS films,
a near linear reduction of the fragility index could be observed between 5–30%
TEC concentration, but above 30%, this value leveled out to constant. 相似文献