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When lithium-ion batteries (LIBs) are located at high altitude and low pressure,the characteristics of thermal runaway (TR) and its propagation are different,such as time to TR, the toxicity of TR gases, TR propagation time, mass loss rate, etc. In this article, the author summarized a series of relevant literatures and proposed an instrument that can be used to analyse the TR behavior at different pressure. It is found that: with the decrease of ambient pressure, the TR trigger time becomes longer and the maximum surface temperature decrease. Moreover, the gas released by TR becomes more toxic as the environmental pressure decreases. Beside, the average propagation time between adjacent LIBs is not much difference when the environmental pressure decreases, and when the 18,650 battery module is distributed in a cylindrical shape, the thermal runaway propagation path is basically unchanged as the environmental pressure decreases. This work details TR and its propagation feature under different pressure, and can provide the guidelines for the Air transportation of LIBs.

During the process of liquid forging, a host of hot cracking defects were found in the Al-Cu-Mg-Zn aluminum alloy. Therefore, mechanical tests and analyses by optical microscope, scanning electron microscope, and X-ray diffraction were performed to research the influences of zinc, magnesium, and copper (three main alloying elements) on hot cracking tendency and mechanical properties. It was concluded that all the three alloying elements exerted different effects on the performances of newly designed alloys. And the impact of microstructures on properties of alloys was stronger than that of solution strengthening. Among new alloys, Al-5Cu-4.5Mg-2.5Zn alloy shows better properties as follows: σb=327 MPa, δ=2.7%, HB=107 N/mm2, and HCS=40.

In alkaline in-situ leaching uranium, oxygen is the most common oxidizer with bicarbonate as a complexing agent. For those sandstone uranium deposits with strongly reductive capacity or complicated hydrogeological environment, the oxidation by oxygen is low efficiency. An efficient leaching method, therefore, is needed for these uranium deposits. In this study, a typical sandstone uranium deposit which characterizes with high TDS and high chloride content in groundwater and intractable uranium leach is selected to investigate the effects of synergetic oxidation by a strong oxidant with oxygen. Based on the research on batch leach, pressure leach and field trials, the oxidants such as hydrogen peroxide, potassium permanganate and sodium dichloroisocyanurate (NaDCC) are tested. The results of pressure batch leach indicate that synergetic oxidization is achieved by NaDCC in oxygen leaching process. Leaching tests indicate that a minor oxidizer of NaDCC shows good synergetic oxidization with oxygen and leaching effects on uranium minerals. The results also demonstrate that hydrogen peroxide shows no oxidation effects when it is used as a single oxidant. While potassium permanganate shows good oxidation on uranium when it is used as a single oxidant, however, it leads inhibiting effects on oxygen oxidation on uranium minerals. The further field tests are conducted to study the synergetic effects of oxygen with and without sodium dichloroisocyanurate. The preliminary results indicate that a fast leach is observed by the composite oxidants in early stage while no synergetic leach is found after 200 days. Further studies should be conducted in laboratory experiments and pilot scale tests for its potential applications.

In this study, catalyst formation [Pb(H2O)6][ATZ]·H2O (ATZ = azo tetrazolium anion) was successfully synthesized originally; meanwhile, the single-crystal structure of the compound was cultivated and analyzed by diffraction single-crystal method. The influence of the compound in which [Pb(H2O)6][ATZ]·H2O was used as combustion catalyst on the decomposition temperature of potassium nitrate was studied by TG–DSC. The result proved that [Pb(H2O)6][ATZ]·H2O can effectively reduce the decomposition temperature. In other words, [Pb(H2O)6][ATZ]·H2O can reduce the decomposition temperature of potassium nitrate, so the addition of [Pb(H2O)6][ATZ]·H2O can make potassium nitrate better to be used in the fields of initiating explosive device and fire engineering.

The objective of this study is to investigate the impact of different fractions (0–0.05) of C6F12O addition on laminar flame speed of hydrocarbon syngas by varying the fuel/oxidizer equivalence ratio (0.6–1.2) using Bunsen burner method. The determination of the syngas composition comes from the venting gas of lithium-ion cell during thermal runaway. It is found that C6F12O is significantly more effective at stoichiometric and fuel-rich conditions compared to lean flames regardless of fuel species, which implies more suitable for syngas/air flame inhibition than CH4. The laminar flame speeds of syngas/air increased with lower concentration (

A novel environmental-friendly unpacking powder for fireworks which has no sulfur, no magnesium, no aluminum or their alloys has been prepared in this study: potassium perchlorate (75%), potassium hydrogen terephthalate (13%), micronano porous silicon (9%), carbon (2%), ferrocene (1%). The PM2.5 and PM10 were collected by the ambient air particulate sampler, and the gas product was tested with a smoke analyzer and gas chromatograph to investigate its environmental-friendly performance. The detonation radius was measured by similar triangulation method, and p–t curves were measured in a closed bomb to investigate its practicality. The heat of combustion, sensitivity and hygroscopicity of the formula were measured according to China fireworks industry standard to verify the safety of the novel unpacking powder. The test results suggest that new unpacking powder using micronano porous silicon can effectively reduce the PM content and the product does not contain SO2, so it can be applied to export.

A quantitative feeding system of molten metal was designed based on a special vehicle cover, which achieved the quantitative transport of molten metal in a fully enclosed environment. There are lots of advantages of this novel device, such as improving the accuracy of the molten metal pouring, reducing the oxide inclusions defects, improving the quality of forming parts, etc. The numerical simulation of the casting process of filling mold was carried out based on the software ProCAST, which optimized the processing parameters of the quantitative feeding device. The result shows that the optimal movement speed of the punch piston is 0.08 m/s. The forming process of the aluminum alloy cover was designed and the process was conducted on the novel quantitative feeding device of molten metal. The structure and process performance of the forming parts were summarized and the defects were analyzed. The influence of technological parameters such as pouring temperature, filling speed, initial mold temperature, and feeding distance on the quality of forming parts was studied, which resulted in the optimum process parameters for the dosing device.

Gas generators are the functional materials producing gas by combustion. In situations such as pneumatics, fire extinguishing bomb, air bag, deep-water salvage, the gas generators can be ignited to provide power and energy through rapid release of gas. However, the research about gas generators with low water vapor is blank in world. The most widely used gas generators (such as nitroguanidine gas generators) produce a lot of water vapor through combustion, whose liquefaction will cause the reduction of gas pressure. This work selected 4,5-diazolyl-1,2,3-triazole (BTTZ) as gas-generating material. Two kinds of gas generator formulations based on BTTZ with common oxometallate (KNO3) and metal oxide (CuO) were designed. The properties of these gas generator formulations were studied by calculation and experiments. The gas production, gas production rate, water vapor content, compatibility and mechanical sensitivity were measured. The gas specific volume of the formulation 1 was 4.08 m3 kg−1. The clean harmless gas content reaches 93.55%. The water vapor content of the product was 6.08% (volume percentage), which is much lower than the nitroguanidine gas generators (53.47%). Therefore, formulation 1 is a low-water vapor environmental-friendly gas generator as a cleaner production material with practical value.

Black powder is often used as propellant in the fireworks industry, but the sulphur in the black powder will pose great risks to the environment and human health. Although there are sulphur-free propellant with metal powder and smokeless propellant prepared from expired military gunpowder to solve the problem, the high sensitivity and huge explosive power of the mental powder and instability of the expired military gunpowder lead to low security in actual application. Therefore, sulphur-free propellant which can replace black powder is urgently needed. In this study, a discharge height test was conducted for the sulphur-free environmental protection formulation [potassium perchlorate (70%), potassium hydrogen terephthalate (10%), carbon (11%), ferrocene (1%), phenolic resin (7%), calcium stearate (2%)] optimized by an orthogonal test. The thermal explosion in critical temperature was used to determine the thermal stability of sulphur-free propellant and black powder, then compared with combustion heat. The preesure-time test was used to compare the peak pressure of this two propellant. The impact, friction and flame sensitivity were also measured. It is thought that sulphur-free propellant can replace the black powder as the new environmental-friendly propellant in the fireworks industry with low sensitivity and excellent storage performance, and have great potential in application.

This work sets focus on producing hydrophobic silica and fire-extinguishing-composition solution into dry water extinguishant powder by high-speed shearing. The solid-to-liquid ratio, different stirring periods and rotational speed were taken into account to analyze their influence on the covering effect. The dry water extinguishants containing ammonium dihydrogen phosphate (ADP) and phosphoric acid are respectively produced added with gel. The jet apparatus is improved for the experiment. According to the results, the phosphoric acid gel dry water extinguishant works best to put out Type-A fire. The ADP dry water extinguishant excels in putting out Type-B fire, equivalent to superfine ABC dry powder extinguishant in terms of effectiveness but with a low cost. For this reason, dry water extinguishant has a broad prospect of application.

Mg-Zn-Zr-Y billets with different mass fraction of Y (wt%(Y)=0.2%、0.5%、1.0%、1.5%、2.0%) was prepared by permanent mold casting. The increase in Y content has shown grain refinement effects on the microstructure morphologies of Mg–Zn–Y–Zr alloys. When the content of Y achieves 1.0 wt%, the grain refinement effect of the Y is most obvious than any more contents of the Y content. In the test result of XRD, the type of precipitated phase in Mg-Zn-Zr-Y alloys is related to atomic ratio of Y/Zn. With content of Y increases, atomic ratio of Y/Zn increases,the precipitated phase in alloy is changed from Phase I to Phase W. Tensile strength and extension rate of alloy increase with the increasing of Y content; When Y content reaches 1.0%, mechanical property reaches maximum value.When content of Y exceeds 1.0%, with the increasing of Y content, mechanical property of alloy declines gradually.

The normal pyrotechnically generated aerosol extinguishing agent is effective in extinguishing Class B fire, but have difficulty extinguishing the Class A wood-crib fire. To solve this problem, an experiment has been made in this paper to study the extinction effectiveness of a new type of pyrotechnically generated aerosol extinguishing agent in wood crib fire. Differing from the old ones, the new type of pyrotechnically generated aerosol extinguishing agent generates via combustion of aerosol forming agents containing a kind of phosphorus-containing compound named P90x, which is flammable and has been widely used as fire retardants in materials. P90x was added, for the first time, as a reducer into aerosol forming agents to improve the capabilities against the Class A wood-crib fire. Five aerosol forming agents with the different mass ratio of P90x and potassium nitrate were tested for fire extinguishing efficiency. The fire extinguishing efficiency increased as the amount of P90x increases. And the best fire extinguishing efficiency in this experiment was 20 g/m 3 for wood-crib fire. This new type of aerosol extinguishing agents can adhere to the surface of burning wood and react with it to extinguish fire efficiently. Therefore, the Class A fire (wood cribs) can be extinguished by pyrotechnically generated aerosol extinguishing agents for the first time from all over the world.

Up to now, the research studies about 5-aminotetrazole (5-AT) gas generators are still not complete. In this work, ten gas generators based on 5-AT with different ordinary oxidants were designed. A...

The Nalinggou–Daying uranium metallogenic belt is situated at the northern Ordos Basin, China. Petrographical, mineralogical and geochemical techniques were used to study the ore-bearing sandstones and host rocks in the Nalinggou–Daying uranium metallogenic belt. The present study shows that uranium minerals, i.e., coffinite, pitchblende, and brannerite, are mostly disseminated around pyrite and detrital particles. The ore-bearing sandstones are enriched in organic matter, with which this reductive environment influenced uranium leaching. The carbonate concentration of the uranium ores is markedly higher than that of the host rocks, and intense carbonatization occurs in the ore-bearing sandstones. In this case, the usage of the classical in-situ leach uranium mining technique by injecting H2SO4 + H2O2 solution produces calcium sulfate precipitate, which can lead to blocking of the ore-bearing strata. For this reason, laboratory and field uranium mining tests were conducted using CO2 + O2 in-situ leaching technology and were demonstrated to be successful, illustrating that this approach is technically feasible. Inhibiting ore bed blockage and increasing the amount of injected O2 are important for uranium leaching in this setting.

Six types of gas generators based on guanidinium azotetrazolate (GZT) were designed into six formulations having different oxidants: GZT-LiNO3 (1), GZT-NaNO3 (2), GZT-KNO3 (3), GZT-Mg(NO3)2 (4), GZT-Sr(NO3)2 (5) and GZT-KMnO4 (6), respectively. The properties of these formulations were investigated in terms from gas production, appropriate combustion temperature and nontoxic gaseous emission. REAL software calculation program [1] was used to calculate the combustion heat at constant pressure, combustion heat at constant volume and specific volume in standard state. It showed that gas generators based on GZT with nitrate salts as oxidant exhibited better performance. Thus its thermal behavior and combustion temperature were studied further and the experimental results were consistent with the theoretical calculation results. Therefore, it can be concluded that formulation 3 has comprehensive optimal performance: low moisture content, insensitivity to friction, heightened vacuum stability, high combustion heat and specific volume. Namely, formulation 3 exhibited the most promising indications of commercial application, such as using in air bags of motor vehicles.

A cup burner was used to measure the minimum fire extinguishing concentrations for methane extinguishment by fine water mist with additives/air co-flow diffusion flames based on ultrasonic atomization. The comparison of the minimum fire extinguishing concentrations of pure and fine water mist revealed that the existence of additives could change the fire extinguishing efficiency of pure water, with their improvement effect ranked as KCl > KH 2 PO 4 > NH 4 H 2 PO 4 . A flame thermal balance equation was established, and a model for predicting the minimum fire extinguishing concentrations of different fire extinguishing agents was developed. A differential scanning calorimeter was used to measure solution heat capacity, and the physicochemical properties of different liquid extinguishers were predicted. When the mass fractions of the additives equated to 2%, the chemical fire extinguishing effect was superior. The influence of additives on fire extinguishing efficiency mainly involves an increase in chemical actions and a reduction in the competition between the evaporative capacities of pure water.

Solid–liquid segregation often occurred during thixoforming of wrought aluminum alloys, which can result in uneven structures and mechanical properties. In this work, a novel compound loading method was introduced in thixoforming 7075 aluminum alloys. The results show that the solid–liquid segregation can be alleviated evidently by compound loading, and the microstructures of periphery area were improved significantly. As the secondary loading displacement increased from 0 mm to 5 mm, the ultimate tensile strength (UTS) of the periphery area increased little (∼510 MPa), and the yield strength (YS) even decreased slightly from 486 MPa to 470 MPa. However, the elongation to fracture of the periphery area increased from 1.94% to 4.3% with increment of 122%. On the contrary, the compound loading has limited effect on the tensile mechanical properties of the center area. The tensile fracture surfaces exhibited typical brittle rupture in the periphery area, while the fracture surfaces of the center were dominated by a large number of dimples and tear ridges showing typical ductile fracture features. Compound loading is an effective method to homogenize the microstructures and mechanical properties of thixoformed wrought aluminum alloys.

1,5-diaminotetrazolium chloride (DATC) and 1,5-diaminotetrazolium sulfate (DATS) were synthesized in this work. The structures of DATS and DATC were characterized. The single crystal of DATS was first cultured, and its structure was analyzed. The thermal behavior of DATS was investigated. The activation energy and pro-exponential factor were calculated, Ek = 120.86 KJ/mol, Ak = 1012.96 s−1. The density, heat of formation, detonation pressure, and detonation velocity of DATS were first calculated. The detonation pressure and detonation velocity of DATS are P = 11.877 GPa, D = 5.617 km s−1, which are smaller than those of 1,5-diaminotetrazolium nitrate (DATN) (P = 33.3GPa, D = 8.77 km s−1).

The synthesis mechanism of 3-nitro-4-(tetrazol-5-yl)furazan (NTZF) was calculated by Gaussian 09 for the first time, and NTZF was successfully synthesized based on the theoretical design. Its ionic salts (RbNTZF and CsNTZF) were synthesized and studied by single-crystal X-ray diffraction firstly. The thermal stability of NTZF was investigated by TG-DSC and the kinetic data of thermal decomposition were calculated. The sensitivity of NTZF was measured. The formation heat, detonation velocity (D) and detonation pressure (P) of NTZF were calculated. NTZF is insensitive to impact and friction (impact > 40 J, friction > 360 J) and has higher detonation velocity and pressure (D = 7.838 km s−1, P = 27.32 GPa) compared to TNT (D = 6881 m s−1, P = 19.5 GPa). NTZF has appropriate sensitivity and detonation performance, so it can be used as a low explosive and gas generant.

2-Methyl-4,5-dicyano-2H-1,2,3-triazole was synthesized with 4,5-dicyano-2H-1,2,3-triazole as the raw material for the first time. Its structure was characterized by elemental analysis, infrared spectrum, and nuclear magnetic resonance spectrum. The thermal stability of 2-methyl-4,5-dicyano-2H-1,2,3-triazole was investigated by TG–DSC technique. Its kinetic parameters including activation energy and pre-exponential factor were calculated by Kissinger equation. The combustion heat, heat of formation, impact and friction sensitivity of 2-methyl-4,5-dicyano-2H-1,2,3-triazole were measured. Also, 2-methyl-4-acylamino-5-cyano-2H-1, 2,3-triazole was formed by the hydrolysis of one of the cyano groups of the 2-methyl-4,5-dicyano-2H-1,2,3-triazole, and its single crystal was cultivated. The molecular structure of 2-methyl-4-acylamino-5-cyano-2H-1,2,3-triazole was determined using X-ray diffraction [triclinic P-1, a = 4.956(2) A, b = 10.058(5) A, c = 14.142(7) A, β = 91.169(4)°, V = 658.7(6) A3, Z = 4]. It exhibited potential application prospect in gas generant, explosive, and solid propellant field.

4,5-Bis(5-tetrazolyl)-1,2,3-triazole (BTT) was synthesized by a new method. Its structure was characterized by IR and 13C NMR spectroscopy and elemental analysis (EA). The thermal stability of BTT was investigated by TG-DSC technique. The kinetic parameters including activation energy and pro-exponential factor were calculated by Kissinger equation. The combustion heat, detonation products, hygroscopicity, impact, and friction sensitivity were also measured. The formation heat, detonation pressure, and detonation velocity of BTT were calculated. BTT has high detonation pressure and detonation velocity (P=35.36 GPa, D=8.971 km s−1). BTT has potential application prospect as environmentally friendly gas generant, insensitive explosive and solid propellant.

Bis (1, 5-diamino-4-methyl-tetrazolium) azotetrazolate (BMDATZT) was synthesized with high yield in this work. The yield is 97.46%. The structure was characterized by IR, 1H NMR, and MS. The single crystal of BMDATZT•2H2O was first cultivated. The heat of formation, detonation pressure, and detonation velocity were first calculated. The crystalline density of BMDATZT•2H2O is 1.573 g/cm3. BMDATZT has high detonation pressure and detonation velocity (P =25.06 GPa, D = 7.805 km s−1), which are higher than those of 2,4,6-Trinitrotoluene (TNT). Its thermal and mechanical sensitivities are moderate. Therefore, it is a kind of insensitive nitrogen-rich energetic ionic salt with good performance, and it has potential application prospect in gas generating agent, explosive and solid propellant.

Al-Zn-Mg-Cu alloys are the strongest aluminum alloys which have been widely used for aerospace applications. They are usually machined from the wrought state usually with a high waste percentage. To reduce waste, it is important to thixoform these alloys in near net shape. In this work, the thixoformability of a commercial high performance Al-Zn-Mg-Cu alloy 7075 was studied. A novel multistep reheating regime was developed in recrystallization and partial melting (RAP) route to obtain spheroidal semi-solid microstructures. The as-extruded 7075 alloy was fully recrystallized for a short holding time using the multistep reheating regime. Semi-solid microstructures with fine and spherical solid grains with a grain size of 40-50 μm embedded in liquid matrix were obtained. The advantage of the multistep reheating regimes over those conventional routes was also discussed. Some wheel-shaped components were thixoformed from the as-received 7075 alloy. The ultimate tensile strength, yield strength and elongation to fracture of the thixoformed component based on multistep reheating regime, are 510 MPa, 446 MPa and 17.5% respectively. These values are superior to those of the products manufactured with the conventional RAP route. As the results indicated, thixoforming could be conducted based on commercial extruded Al-Zn-Mg-Cu alloys, which has important practical significance.

The synthesis and characterization of the 4,5-dicyano-2H-1,2,3-triazole anion in its 5-aminotetrazole, 1,5-diaminotetrazole, and 1,5-diamino-4-methyl-tetrazole salts are reported. All compounds were characterized by IR, 1H NMR, and 13C NMR spectroscopy, as well as elemental analyses. Their thermal decompositions were investigated by TG-DSC. The densities, combustion heats, and sensitivity properties were tested. Additionally, enthalpies of formation, detonation pressures, detonation velocities, and heats of detonation were calculated. The compounds have potential application in the energetic materials field.

Taking carbon series conductive coatings as the research object, research on a modificatory filler was carried out to achieve higher electrical conductivity. Under the condition of this paper, the conductivity of the modified carbon black was improved, while the performance of the modified graphite was not obviously improved. The conductivity and dispersion of the modified carbon fibre were both improved. Analysing the impact of the additive on the performance of conductive coatings in which carbon black accounted for 10%, the conductivity was best when the weight of the tetra-butyl titanate was 1% of the filler. Adding an anti-settlement agent also improved the performance of the conductive coatings, and the best consumption was about 0.6% of the weight of the filler.

The nitrogen content of tetrazolo[l,5-b][1,2,4]triazine is 68.9%. It has a good application prospect in energetic material field. The synthesis was carried out, and the single crystal was cultivated. The analysis showed that the two rings of tetrazolo[l,5-b][1,2,4]triazine are in the same flat, and the molecular accumulation displayed the net-like structure in the space. The thermal decomposition process was studied. The relationship between weight loss and temperature, and the thermal decomposition temperature were gained from thermogravimetry-differential thermogravimetry and differential scanning calorimetry. These provide the reference for its application in energetic material.

1,1′-Diamino-5,5′-azotetrazole (DAZT) has been synthesized using acetic acid (HAc) and 1,1′-diisopropylideneamino-5,5′-azotetrozole (DPrZT) as the raw material. Three of the most important factors which affect the yield of DAZT are the reaction temperature, the reaction time, and n(DPrZT):n(HAc). Based on single-factor experiments, orthogonal experiments were carried out. The most optimal experimental conditions were determined to be: a reaction temperature of 70 °C, a reaction time of 20 min, and a reactant ratio n(DPrZT)–n(HAc) of 1:48. The maximum yield was 97.6 % under optimum reaction conditions. Elemental analysis, IR, and NMR confirmed the structure of DAZT. The morphology was analyzed by SEM. The thermal decomposition behavior of DAZT was investigated by TG-DSC and DTA techniques. The mode of thermal decomposition was analyzed. The kinetic parameters including activation energy and pre-exponential factor were calculated from the Kissinger equation. The mechanical sensitivity on this compound was evaluated. Results suggest that it might be useful as an energetic material.

1,1′-diisopropylideneamino-5,5′-azotetrozole (DPrZT) was synthesized with 1-isopropylideneamino-5-aminotetrozole as the raw material and sodium urate isocyanide dichloride as oxidant. Three of the most important factors which affect the yield of DPrZT were gained from the single factor experiments. Based on the single factor experiments, the orthogonal experiments were carried out. The most optimal experimental condition was gained as follows: In the first stage, the reaction temperature was 30 °C, the reaction time was 20 min, and the dropping temperature was 30 °C; In the second stage, the reaction temperature was 30 °C, the reaction time was 20 min, and n(HAc):n(SDCI) was 0.5. The maximum yield was 89.6 % under the optimum reaction condition. The structure and performance of DPrZT were studied in detail in this paper. It showed good thermal stability and explosive performance. It exhibited prospective application in explosion field.

1,5-Diaminotetrazolium nitrate (HDATN) was synthesized with 1,5-diaminotetrazole (DAT) as the raw material. The maximum yield of HDATN was 95.3 %. The structure was characterized by elemental analysis, infrared spectrum, nuclear magnetic resonance spectrum and mass spectrum, and the possible fragmentation mechanism was discussed. The morphology was analyzed by SEM. The thermal stability of HDATN was investigated by TG-DSC and DTA techniques. The kinetic parameters including activation energy and pro-exponential factor were calculated by Kissinger equation. The performance of combustion, combustion heat, and formation enthalpy of HDATN were measured. The detonation products of HDATN were most nitrogen, which were analyzed by gas chromatograph and smoke analyzer. The density, formation heat, detonation pressure, and detonation velocity of HDATN were calculated. It exhibited prospective application in environmentally friendly gas generant and explosion field.

As a new azide-free gas generating pyrotechnic composition, the performance of four kinds of 5-aminotetrazole nitrate (5-ATN) gas generating compositions were investigated by hygroscopicity, compatibility, impact sensitivity, heat of combustion and burning temperature measurement. The advantages of the gas generant using KNO3 as an oxidizing agent include small hygroscopicity, better compatibility, lower impact sensitivity and proper burning temperature. The degree of water sorption in the mixed system with Sr (NO3)2 was much higher than that with KNO3. The participation of CuO can reduce the hygroscopicity of the system with Sr (NO3)2. As the oxidizing agent and catalyst, CuO can also decrease the impact sensitivity, heat of combustion and burning temperature of both systems. 5-ATN gas generant provides fair compatibility using 5-ATN as separate system.

Bis(1,5-diamino-4-methyl-tetrazolium)hydrazinetetrazolate (BMDATHBT) was synthesized for the first time from 1,5-diamino-4-methyl-tetrazolium sulfate (MDATS) and hydrazino bitetrazole barium (HBTBa·5H2O) as raw materials. The structure was characterized by elemental analysis, IR, 1HNMR and MS. A single crystal of BMDATHBT was cultivated. Its crystalline density was 1.660 g cm−3. BMDATHBT has high detonation pressure and detonation velocity (P = 25.93 GPa, D = 7.839 km s−1), which are higher than those of TNT. Its thermal and mechanical sensitivities are moderate. The thermal decomposition products are almost all gases. Therefore, it has potential application prospects as a gas generating agent, explosive and solid propellant.

To study the influence of temperature on cylindrical fireworks and crackers in production and storage, this article establishes a physical and mathematical model of thermal explosion critical ambient temperature of finite cylindrical fireworks with shell based on two-dimensional steady state thermal explosion theory. The numerical program is written by difference method and Newton-homotopy method. The partial differential equations of thermal explosion model are calculated in Matlab. Comparison of numerical solutions and classical solutions proves the accuracy of model. The influence of Biot number of each surface and length diameter ratio on critical ambient temperature is analyzed. It is founded that the scope of length diameter ratio is \( 0.08 < H < 4.3 \) when Biot number tends to infinite. The thermal safety temperature of the fireworks without inner barrel when it is stored individually is obtained. This provides theoretical support for the safety of fireworks and crackers in production, storage transportation, and setting off process.

The high strength 7xxx series aluminium alloys are usually difficult to be prepared as semi-solid feedstock, because some dispersoid particles (soluble only in liquid) could pin at grain and subgrain boundary to make the alloy difficultly recrystallise. In this work, a novel multistep reheating regime is developed for recrystallisation and partial melting (RAP) route to prepare fine spheroidal microstructure of semi-solid Al–Zn–Mg–Cu alloy. After reheating to 665 °C, holding for 4 min and subsequent isothermally holding at 620 °C with total heating time of 15 min, fine spheroidal microstructures with grain size of ∼40 μm were prepared without remained unrecrystallised grains and directionality, which are much finer than the conventionally obtained microstructures (∼100 μm).

In order to study the influence of the environmental humidity on thermal decomposition of pyrotechnic compositions, this experiment has been set up with artificial simulation environment of high humidity. The thermal analysis experiments have been done by using the integrated thermal analyzer. Thermal decomposition curves in the high humidity environmental conditions and the normal environmental conditions have been obtained. And the starting temperature, peak temperature, as well as the change rules of the activation energy in the decomposition reaction have been gotten, which shows that the thermal safety of the pyrotechnic compositions in the high humidity environment is lower.

In order to analyze thermal safety of fireworks and crackers, thermal explosion models of three kinds of sphere fireworks and crackers with different structures are achieved on the basis of thermal explosion theory, and thermal resistance of shell and effective Biot number are deduced as for boundary conditions. Two models are calculated with target-shooting method in Matlab program, and the rationality is proved through comparison of numerical solution and classical solution. Meanwhile, calculation steps are shown about a type of firework. The study has a great significance to thermal safety analysis of fireworks and crackers.

Pyrotechnical battery is successfully prepared, including an anode and cathode having pyrotechnic charges with an excess of fuel-anode and an excess of oxidation agent cathode (Zr, CuO and asbestos), the anode and cathode being separated by a separator formed from LiF, ZrO2 and fibrous sponge. Main performance indexes system of pyrotechnical battery is put forward and tested under the premise of appropriate mass and corresponding size, such as discharge voltage, discharge time, activation time, excitation time, internal resistance, combustion temperature and storage life. The results show that pyrotechnical battery of Zr/CuO system can basically meet application requirements. Activation time is usually about 0.2 s. Discharge voltage is about 1.96 V and the discharge time is up to 13.8 s or more. The internal resistance keeps a low fixed value (0.47Ω , for example). Combustion temperature of pyrotechnic composition can reach 1500.6 °C (the case temperature of battery is lower) to ensure that electrode and separator is adequately melted, consequently, the internal resistance is reduced, and achieving satisfactory discharge effect.

An easy method to synthesize hollow carbon nanospheres (HCSs) with polystyrene as template and phenol as precursor is reported. The obtained HCSs have very thin shells and big hollow cores. The diffraction peaks of X-ray diffraction patterns located at about 2 θ = 22° and 43° are assigned to the (0 0 2) and (1 1 0) graphite plane of HCSs. Transmission electron microscopy shows every state in the synthesis process of HCSs.

Ventricular hypertrophy is a powerful and independent predictor of cardiovascular morbid events. The vascular properties of low-dose acetyl salicylic acid (aspirin) provide cardiovascular benefits through the irreversible inhibition of platelet cyclooxygenase 1; however, the possible anti-hypertrophic properties and potential mechanism of aspirin have not been investigated in detail. In this study, healthy wild-type male mice were randomly divided into three groups and subjected to transverse aortic constriction (TAC) or sham operation. The TAC-operated mice were treated with the human equivalent of low-dose aspirin (10 mg·kg(-1)·d(-1)); the remaining mice received an equal amount of phosphate buffered saline with 0.65% ethanol, which was used as a vehicle. A cardiomyocyte hypertrophy model induced by angiotensin II (10 nmol·L(-1)) was treated with the human equivalent of low (10 or 100 μmol·L(-1)) and high (1000 μmol·L(-1)) aspirin concentrations in plasma. Changes in the cardiac structure and function were assessed through echocardiography and transmission electron microscopy. Gene expression was determined through RT-PCR and western blot analysis. Results indicated that aspirin treatment abrogated the increased thickness of the left ventricular anterior and posterior walls, the swelling of mitochondria, and the increased surface area in in vivo and in vitro hypertrophy models. Aspirin also normalized the upregulated hypertrophic biomarkers, β-myosin heavy chain (β-MHC), atrial natriuretic peptide (ANP), and b-type natriuretic peptide (BNP). Aspirin efficiently reversed the upregulation of β-catenin and P-Akt expression and the TAC- or ANG II-induced downregulation of GSK-3β. Therefore, low-dose aspirin possesses significant anti-hypertrophic properties at clinically relevant concentrations for anti-thrombotic therapy. The downregulation of β-catenin and Akt may be the underlying signaling mechanism of the effects of aspirin.

The molecule of the title compound, C6H8N6, is approximately planar, with a maximum deviation from planarity of 0.099 (1) Å. In the crystal, molecules are linked to each other via pairs of N—H...N hydrogen bonding, forming inversion dimers. The crystal structure is further stabilized by π–π stacking interactions, with a centroid–centroid distance of 3.419 (1) Å.

1,1′-Diamino-5,5′-azotetrazole, which was obtained from the reaction of 1,5-diaminotetrazole with acetone, sodium dichloroisocyanurate and acetic acid respectively, was well characterized. Its structure was confirmed by X-ray crystallography and the thermal stability and explosive performance were also investigated.

In the crystal structure of the title compound, C7H10N6O3, there are N—H...O, N—H...N and C—H...O interactions, generating a three-dimensional supramolecular network structure. A short intermolecular O...C contact of 2.8994 (18) Å is alsopresent in the crystal structure, but no π–π contacts are observed.

The molecule of the title compound, C4H8N6, assumes an approximately planar structure, the methyl C atoms and the C atom to which they are bonded being out of the mean tetrazole ring plane by 0.108 and 0.139, and 0.144 Å, respectively. π–π stacking between parallel tetrazole rings [centroid–centroid distance = 3.4663 (11) Å] is observed in the crystal structure. Intermolecular N—H...N hydrogen bonding further helps to stabilize the crystal structure.