RESUMEN
Nowadays, thousands of energetic materials have been synthesized, but only a few compounds meet all the high standards of detonation performance comparable to that of the widely used military explosive RDX, thermal stability comparable to that of the most widely used heat-resistant explosive HNS, and impact sensitivity comparable to that of the traditional explosive TNT. Also, as a goal, a novel and unexpected one-step method for constructing the furoxan-bridged energetic compound 3,4-bis(3,8-dinitropyrazolo[5,1-c][1,2,4]triazin-4-amino-7-yl)-1,2,5-oxadiazole 2-oxide (OTF) has been achieved under the conventional TFA/100% HNO3 nitration reaction system from the acetic acid intermediate. In this work, OTF with a high density of 1.90 g cm-3, the highest decomposition temperature of 310 °C (onset) among furoxan-based high explosives to date, superior detonation velocity (DV: 9109 m s-1), and low sensitivity (IS: 25 J) is reported. This work is a giant step forward in the development of advanced high-energy heat-resistant explosives and could improve future possibilities for the design of furoxan-based energetic materials.
RESUMEN
Here, azo-fused dinitramino energetic compound 5,5'-dinitramino-8,8'-azo-1,2,5-oxadiazolo[3,4-e][1,2,4]triazolo[4,3-a]pyrazine (4) and its energetic salts 5-7 have been prepared. Azo-fused dinitramino compound 4 exhibits excellent detonation performance (P = 36.13 GPa, and Dv = 9126 m s-1), which is obviously better than that of RDX (Dv = 8796 m s-1, and P = 33.60 GPa). In addition, the thermal stability of carbonyl compound 2 (Td = 325 °C) is similar to that of HNS (Td = 318 °C) and 2 exhibits better energy properties. These properties indicate that azo-dinitramino compound 4 has potential as a new secondary explosive, while carbonyl compound 2 also has potential as a new type of heat-resistant explosive.
RESUMEN
A quadruped robot with intelligent properties is developed using a bionics approach to explore the potential value of gecko-like machinery. The robot structure incorporates mechanical links, steering engines, and wheel groups, which can expand the movement function of its leg joint. A pneumatic control circuit that can generate negative pressure is built by a vacuum pump, electromagnetic valve, sucker, hose, and others, to enable mobile climbing and adsorption of the gecko-inspired robot. By integrating gait planning, program compilation, Arduino board development, theoretical calculation, and digital modeling, the robot incorporates several practical functions such as "adsorption climbing, ultrasonic obstacle avoidance, remote control, Bluetooth communication, WiFi wireless image transmission, and multi-terrain maneuvering," which give a basis to realize the multi-dimensional integrated design of "machine, electricity, gas and intelligence" of biomimetic gecko. The experimental prototype of the gecko-inspired robot is designed and manufactured with 3D printing, combined with virtual prototype development, mechanism trajectory verification, finite element analysis, and CFD hydrodynamic simulation. Test results indicate that the biomimetic body has ideal characteristics of intelligent control and maneuvering response in the natural environment, which specifically manifested as that the robot can carry out stable adsorption and climb on the vertical wall, respond quickly to avoid obstacles intelligently, and detect and monitor the external environment in real-time with the help of a mobile phone control terminal. This work is promising for solving high-risk social production and engineering operation challenges.
RESUMEN
In recent years, with the development of deep coal mines and petroleum resources and the expansion of the aerospace industry, the pursuit of heat-resistant energetic materials with high thermal stability and high energy has been increasing. Bis(4-nitropyrazole) was employed as an energy bridge to link 1,2,4-triazole, thereby constructing a sophisticated tetracyclic framework in this study. A tetracyclic heat-resistant explosive 5,5'-(4,4'-dinitro-2H,2'H-[3,3'-bipyrazole]-5,5'-diyl)bis(4H-1,2,4-triazole-3,4-diamine) (3) and its derivatives 6-8 with excellent comprehensive performance have been successfully prepared. Particularly noteworthy is that compound 3 has a detonation velocity of 8604 m s-1, which exceeds that of the conventional heat-resistant explosive HNS with a velocity of 7164 m s-1. Furthermore, compound 3 has higher thermal stability (Td = 340 °C) than HNS (Td = 318 °C). In addition, the tetracyclic compound 3 also exhibited extraordinarily low sensitivity (IS > 40 J; FS > 360 N). These unique characteristics make it a potential candidate for novel heat-resistant and insensitive energetic materials.
RESUMEN
It is still an urgent problem in the field of energetic materials to explore the synthesis of heat-resistant compounds with balanced energy and thermal stability through simple synthetic routes. Recently, fused compounds are considered to provide a promising framework for the construction of ideal heat-resistant compounds. In this study, three novel C-C bonded bis-5,6 fused triazole-triazine compounds, 3,3'-dinitro-[7,7'-bi[1,2,4]triazolo[5,1-c][1,2,4]triazine]-4,4'-diamine (2), 4,4'-diamino-[7,7'-bi[1,2,4]triazolo[5,1-c][1,2,4]triazine]-3,3'-dicarbonitrile (3), and 3,3'-di(1H-tetrazol-5-yl)-[7,7'-bi[1,2,4]triazolo[5,1-c][1,2,4]triazine]-4,4'-diamine (4), were synthesized by a simple method. Compound 2 exhibited an approaching detonation velocity of 8837 m s-1 compared with that of the traditional high energy explosive RDX velocity of 8795 m s-1, while its thermal stability (Td = 327 °C) was comparable to that of the heat-resistant explosive HNS (Td = 318 °C). At the same time, the double fused compound 2 also realized high density (1.90 g cm-3) and extremely low sensitivity (FS > 360 N, IS > 40 J). The above good comprehensive properties prove that compound 2 can be used as a potential insensitive high-energy heat-resistant explosive. In addition, the effects of the crystal structure on the sensitivity and thermal stability were studied using the quantum chemical methods. These results imply that the formation of double fused ring compounds by the ring closing reaction at symmetrical positions is an ideal strategy for the development of advanced heat-resistant explosives.