Over the past century, the search for lead-free, environmentally friendly initiating substances has been a highly challenging task in the field of energetic materials. Here, an organic primary ...explosive featuring a fused-ring structure, 6-nitro-7-azido-pyrazol3,4-d1,2,3triazine-2-oxide, was designed and synthesized through a facile two-step reaction from commercially available reagents. This organic initiating substance meets nearly all of the stringent criteria of environmentally friendly primary explosives for commercial applications: it is free of toxic metals and perchlorate, has a high density, high priming ability, unusual sensitivities towards non-explosive stimuli, excellent environmental resistance, decent thermal stability, high detonation performance, satisfactory flowability and pressure durability, and is low-cost and easy to scale-up. These combined properties and performance measures surpass the current and widely used organic primary explosive, DDNP. The fused-ring organic primary explosive reported herein may find real-world application as an initiating explosive device in the near future.
A promising high-energy-density material Zhang, Wenquan; Zhang, Jiaheng; Deng, Mucong ...
Nature communications,
08/2017, Letnik:
8, Številka:
1
Journal Article
Recenzirano
Odprti dostop
High-energy density materials represent a significant class of advanced materials and have been the focus of energetic materials community. The main challenge in this field is to design and ...synthesize energetic compounds with a highest possible density and a maximum possible chemical stability. Here we show an energetic compound, 2,2'-bi(1,3,4-oxadiazole)-5,5'-dinitramide, is synthesized through a two-step reaction from commercially available reagents. It exhibits a surprisingly high density (1.99 g cm
at 298 K), poor solubility in water and most organic solvents, decent thermal stability, a positive heat of formation and excellent detonation properties. The solid-state structural features of the synthesized compound are also investigated via X-ray diffraction and several theoretical techniques. The energetic and sensitivity properties of the explosive compound are similar to those of 2, 4, 6, 8, 10, 12-(hexanitrohexaaza)cyclododecane (CL-20), and the developed compound shows a great promise for potential applications as a high-energy density material.High energy density materials are of interest, but density is the limiting factor for many organic compounds. Here the authors show the formation of a high density energetic compound from a two-step reaction between commercially available compounds that exhibit good heat thermal stability and detonation properties.
Finding new high-energy-density materials with desired properties has been intensely-pursued in recent decades. However, the contradictory relationship between high energy and low mechanical ...sensitivity makes the innovation of insensitive high-energy-density materials an enormous challenge. Here, we show how a materials genome approach can be used to accelerate the discovery of new insensitive high-energy explosives by identification of "genetic" features, rapid molecular design, and screening, as well as experimental synthesis of a target molecule, 2,4,6-triamino-5-nitropyrimidine-1,3-dioxide. This as-synthesized energetic compound exhibits a graphite-like layered crystal structure with a high measured density of 1.95 g cm
, high thermal decomposition temperature of 284 °C, high detonation velocity of 9169 m s
, and extremely low mechanical sensitivities (impact sensitivity, >60 J and friction sensitivity, >360 N). Besides the considered system of six-member aromatic and hetero-aromatic rings, this materials genome approach can also be applicable to the development of new high-performing energetic materials.
A fluorescent ionic liquid material with a dansylamide chromophore was designed and synthesized, which exhibited highly selective sensing ability towards nitroaromatic explosives, especially for ...picric acid (PA).
Display omitted
•A fluorescent ionic liquid with a dansylamide chromophore was synthesized.•The ionic probe showed highly sensitive and selective detection of nitroaromatic explosives, especially for picric acid (PA).•Theoretical calculations and NMR studies have demonstrated that the resonance energy transfer may play a cooperative role in determining the fluorescence quenching efficiency.•The test paper results validated that the unprecedented efficiency of FIL 3 for on-site and instant detection of PA.
A fluorescent ionic liquid with a dansylamide chromophore was designed and synthesized, which exhibited strong green fluorescence both in the solution and in the condensed phase. As a fluorescent sensor, this ionic probe showed highly sensitive and selective detection of nitroaromatic explosives, especially for picric acid (PA). Theoretical calculations and NMR studies have demonstrated that a ground-state charge transfer through a protonation process and favorable electrostatic π–π interactions between ionic probe and PA may be responsible to the fluorescence quenching mechanism. Moreover, the resonance energy transfer (RET) studies explained the higher sensitivity and selectivity of this ionic probe towards PA than other nitro-containing explosives. A fluorescent test paper was also prepared for the on-site and accurate detection of PA, which provided a new clue of thoughts for instant and highly selective detection of nitroaromatic explosives.
A luminescent heterometallic MOF with an interrupted cap topology was synthesized and characterized. This compound exhibits a strong blue-light emission and shows naked-eye selective detection toward ...trinitrobenzene (TNB) even in the presence of other nitro explosives. Furthermore, the compound is also capable of selectively sensing nitroaromatic picric acid (PA) based on the fluorescence quenching mechanism.
A Pt/FeOx catalyst exhibited high CO oxidation activity (TOF of 151 x 10-3 s-1, 1% CO balanced with air, atmospheric pressure, 27 degrees C) was reported. Clear evidence form characterizations show ...that FeOx acting as an oxygen supply is involved in the reaction. A series of FeOx- and Al2O3-supported Pt, Pd catalysts (0.23-2.1%) were prepared in this study. Pt/FeOx exhibited high CO oxidation activity with turnover frequency of 151 x 10-3 s-1 (1% CO balanced with air, atmospheric pressure, 27 degrees C). A systematical study of FeOx- and Al2O3-supported Pt, Pd catalysts by means of X-ray photoelectron spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy, temperature-programmed reduction, H2-O2 titration, and time-resolved CO titration is reported. From 7% to 39% of Fe3+ was reduced to Fe2+ over Fe(OH)x-supported Pd and Pt catalysts, accompanied by Pd, Pt hydrogenation and hydroxyl loss, and a large amount of oxygen vacancies were proposed to be produced. Results of H2-O2 titration and time-resolved CO titration showed that a large amount of oxygen adsorbed onto FeOx support in the presence of Pt, Pd. This made CO oxidations over Pt/FeOx, Pd/FeOx proceed over two adjacent but different active sites (Pt, Pd for CO and FeOx for oxygen) with low apparent activation energies (30-34 kJ/mol), which accounted for their high activity in low-temperature CO oxidation. PUBLICATION ABSTRACT
In a multicenter, randomized trial, live-birth rates did not differ significantly according to fresh- or frozen-embryo transfer among ovulatory women with infertility. Frozen-embryo transfer resulted ...in a lower risk of the ovarian hyperstimulation syndrome.
The fruit of the dioecious plant Actinidia arguta has become a great attraction recently. It has long been difficult to distinguish the genders of hybrid seedlings before flowering, therefore ...increasing the expenditures of breeding. To produce reliable molecular marker for gender identification, this research utilized whole-genome re-sequencing of 15 males and 15 females from an 8-year-old cross population to develop gender specific markers. P51 and P11 were identified as sex-linked markers after verification. Both of these markers, according to the PCR results, only amplified a single band in male samples. These two markers were tested in 97 hybrids (52 females and 45 males) and 31 wild individuals (13 females and 18 males), with an accuracy of 96.88% and 96.09%, correspondingly. This research also verified the universalities of the two markers in Actinidia chinensis samples, and it could be inferred from the PCR results that neither marker was applicable to A. chinensis samples. The BLAST results of the two markers demonstrated that the two markers were closely aligned with different parts of the Y male-specific region of A. chinensis genome, thus they were likely to be useful for the research on the mechanism of sex determination of A. arguta. The two male-linked makers, P51 and P11, have already been used in sex-identification of A. arguta seedlings.
The polarity of a series of ionic liquids (ILs) based on hydroxyethyl-imidazolium moiety with various anions (PF6, NTf2, ClO4, DCA, NO3, AC, and Cl) and their corresponding nonhydroxyl ILs was ...investigated by solvatochromic dyes and fluorescence probe molecules. Most of the nonhydroxyl ILs exhibit anion-independent polarity with similar E T(30) in the narrow range of 50.7−52.6 kcal/mol, except EMImAC (49.7 kcal/mol). However, the polarity of the hydroxyl ILs covers a rather wide range (E T(30) = 51.2−61.7 kcal/mol) and is strongly anion-dependent. According to their E T(30) or E T(33) values, the hydroxyl ILs can be further classified into the following three groups: (Ι) acetate-based hydroxyl ILs HOEMImAC exhibit polarity scale (E T(30) = 51.2 kcal/mol) similar to short chain alcohol and fall in the range of the nonhydroxyl ILs; (II) Hydroxyl ILs containing anions NO3, DCA, and Cl exhibit comparable polarity (E T(30) = 55.5−56.9 kcal/mol), moderately higher than those of their nonhydroxyl ILs; (III) Hydroxyl ILs containing anions PF6, NTf2, and ClO4 possess unusual “hyperpolarity” (E T(30) = 60.3−61.7 kcal/mol) close to protic ILs and water. Kamlet−Taft parameters and density functional theory calculations indicated that the greatly expanded range of polarity of hydroxyl ILs is correlated to an intramolecular synergistic solvent effect of the ionic hydrogen-bonded HBD/HBA complexes generated by intrasolvent HBD/HBA association between the anions and the hydroxyl group on cations, wherein hydroxyl group exhibits a significant differentiating effect on the strength of H-bonding and thus the polarity. Spiropyran-merocyanine equilibrium acted as a model polarity-sensitive reaction indeed shows obviously polarity-dependent solvatochromism, photochromism, and thermal reversion in hydroxyl ILs.
As important regulators, miRNAs could play pivotal roles in regulation of fruit coloring. Actinidia arguta is a newly emerged fruit tree with extensively application prospects. However, miRNAs ...involved in A. arguta fruit coloring are unknown. In this study, A. arguta fruit were investigated at three developmental stages by small RNAs high-throughput sequencing. A total of 482 conserved miRNAs corresponding to 526 pre-miRNAs and 581 novel miRNAs corresponding to 619 pre-miRNAs were grouped into 46 miRNA families. Target gene prediction and analysis revealed that miR858, a strongly candidate miRNA, was involved in anthocyanin biosynthesis in which contributes to fruit coloring. The anthocyanin level was determined in three A. arguta cultivars by UPLC-MS/MS (ultra-performance liquid chromatography coupled with tandem mass spectrometry). In addition, qPCR (quantitative real-time PCR), cluster analysis were conducted as well as correlation analysis. All results were combined to propose a model in which describes an association of miRNA and anthocyanin biosynthesis in A. arguta. The data presented herein is the first report on miRNA profile analysis in A. arguta, which can provide valuable information for further research into the regulation of the miRNAs in anthocyanin biosynthesis and fruit coloring.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
PDF
