排序方式: 共有114条查询结果,搜索用时 15 毫秒
1.
2.
Nitro aromatic compound can be obtained in high yields via nitration of aromatic compound with wet carbon-based solid acid and NaNO_3 under solvent free oxidation at room temperature. 相似文献
3.
Amirfazli A Keshavarz A Zhang L Neumann AW 《Journal of colloid and interface science》2003,265(1):152-160
Contact angle measurements for three n-alkanes, heptane, octane, and nonane, on two different self-assembled surfaces (SAM) are reported as a function of drop size. These liquids all formed low contact angles (below 20 degrees ); the measurements were performed using an accurate method for systems with low contact angle, ADSA-D. The observed drop size dependence of the contact angles was interpreted using the modified Young equation. It was concluded that the observed drop size dependence of contact angles was due to line tension. The choice of systems also provided the opportunity to examine the behavior of the line tension for systems near wetting (i.e., low contact angles). It was determined that the line tension is positive and ranges from below 10(-7) to just below 10(-6) J/m for the systems studied; the observations suggested that the line tension decreases as the contact angle decreases and likely vanishes at complete wetting. 相似文献
4.
5.
6.
Mohammad Hossein Keshavarz Somayeh Moradi Bahman Ebrahimi Saatluo Hadi Rahimi Ali Reza Madram 《Journal of Thermal Analysis and Calorimetry》2013,112(3):1453-1463
A novel general method is introduced to predict deflagration temperature of organic energetic compounds containing at least –NNO2, –ONO2, or –CNO2 groups. Deflagration temperature is an important safety parameter in working with dangerous energetic compounds and their environmental problems. It is shown that the contribution of some molecular structure parameters can be used to interpret thermal decomposition of an energetic compound. For 86 energetic materials (corresponding to 102 measured values) with different molecular structures, the new correlation has the root mean square (rms) and the average deviations of 23.8 and 19.0 K, respectively. The new method is also tested for some energetic compounds with complex molecular structures, e.g., two new organic energetic molecules N,N′-bis(1,2,4-triazol-3yl)-4,4′-diamino-2,2′,3,3′,5,5′,6,6′-octanitroazobenzene (BTDAONAB) and 2,4,6-trinitrophloroglucinol. 相似文献
7.
Narges Zohari Mohammad Hossein Keshavarz Seyed Abolfazl Seyedsadjadi 《Journal of Thermal Analysis and Calorimetry》2014,115(1):93-100
This study presents a novel relationship between electric spark sensitivity of nitroaromatic energetic compounds and their activation energies of thermal decomposition. The new correlation can help to elucidate the mechanism of initiation of energetic materials by electric spark. It can be used to predict the magnitude of electric spark sensitivity of new nitroaromatics, which is difficult to measure. The methodology assumes that electric spark sensitivity of a nitroaromatic energetic compound with general formula CaHbNcOd can be expressed as a function of its activation energy of thermal decomposition as well as optimized elemental composition and the contribution of specific molecular structural parameters. The new correlation has the root mean square and the average deviations of 1.43 and 1.17 J, respectively, for 22 nitroaromatic energetic compounds with different molecular structures. The proposed new method is also tested for eight nitroaromatic energetic compounds, which have complex molecular structures, e.g., 1,3,7,9-tetranitrophenoxazine, 2,4,6-tris(2,4,6-trinitrophenyl)-1,3,5-triazine, and 1-(2,4,6-trinitrophenyl)-5,7-dinitrobenzotriazole. 相似文献
8.
Hafiz M. N. Iqbal Godfrey Kyazze Thierry Tron Tajalli Keshavarz 《Cellulose (London, England)》2014,21(5):3613-3621
In the present study, a novel enzyme-based grafting of poly(3-hydroxybutyrate) [P(3HB)] onto the ethyl cellulose (EC) as a backbone polymer was developed under a mild and ecofriendly environment and laccase was used as a grafting tool. The resulting composites were characterised using various instrumental and imaging techniques. The high intensity of the 3,358 cm?1 band in the FTIR spectra showed an increase of hydrogen–bonding interactions between P(3HB) and EC at that distinct wavelength region. The morphology was examined by scanning electron microscopy, which showed the well dispersed P(3HB) in the backbone polymer of EC. X-ray diffraction pattern for P(3HB) showed distinct peaks at 2-theta values of 28°, 32°, 34°, 39°, 46°, 57°, 64°, 78° and 84°. In comparison with those of neat P(3HB), the degree of crystallinity for P(3HB)-g-EC decreased. The tensile strength, elongations at break and Young’s modulus of P(3HB)-g-EC reached the highest levels in comparison to the film prepared with pure P(3HB) only, which was too brittle to measure any of the above said characteristics. Results obtained in the present study suggest P(3HB)-g-EC as a potential candidate for various biotechnological applications, such as tissue engineering and packaging. 相似文献
9.
4-Amino-1,2,4-triazolium nitrate (4-ATN) is an energetic and non-sensitive ionic liquid, which was introduced as a good candidate in previous works for the replacement of 2,4,6-trinitrotoluene (TNT) in melt-cast explosives. Since previous studies used pure nitric acid for nitration of 4-ATN, the effect of the use of low price industrial nitric acids (50 %, 70 % and 98 %) is investigated on the percent yields of 4-ATN. The thermogravimetric and differential scanning calorimetry (TGA/DSC) are done on the synthesized 4-ATN with impure nitric acid at a heating rate of 10 K · min–1 by the vacuum system. The obtained TGA/DSC curves confirm decomposition of 4-ATN involving melting and dissociation. Derivative thermogravimetric (DTG) curves of 4-ATN at various heating rates are applied to obtain activation energy of thermolysis by several model-free techniques. The calculated activation energies are in the range 78.7–87.7 kJ · mol–1, which are about 10 kJ · mol–1 more than the reported activation energy of industrial TNT (purity 98.2 %), i.e. 66–70 kJ · mol–1. Assessments of detonation performance of 4-ATN are also compared with TNT, which show higher detonation performance of 4-ATN. Thus, 4-ATN can be used with nitramine compounds as melt-cast explosives with higher thermal stability and detonation performance than corresponding nitramine compound/TNT explosives. 相似文献
10.
Javad Hosseini Mehdi Abdolmaleki Hamid Reza Pouretedal Mohammad Hossein Keshavarz 《催化学报》2015,(7):1029-1034
An electrochemical approach to fabricate a nanostructured Fe/Pt-Fe catalyst through electrodepo-sition followed by galvanic replacement is presented. An Fe/Pt-Fe nanostructured electrode was prepared by deposition of Fe-Zn onto a Fe electrode surface, followed by replacement of the Zn by Pt at open-circuit potential in a Pt-containing alkaline solution. Scanning electron microscopy and energy-dispersive X-ray techniques reveal that the Fe/Pt-Fe electrode is porous and contains Pt. The electrocatalytic activity of the Fe/Pt-Fe electrode for oxidation of methanol was examined by cyclic voltammetry and chronoamperometry. The electrooxidation current on the Fe/Pt-Fe catalyst is much higher than that on flat Pt and smooth Fe catalysts. The onset potential and peak potential on the Fe/Pt-Fe catalyst are more negative than those on flat Pt and smooth Fe electrodes for methanol electrooxidation. All results show that this nanostructured Fe/Pt-Fe electrode is very attractive for integrated fuel cell applications in alkaline media. 相似文献