No abstract

[a] 1IntroductionSemiconductor bridges (SCB), whose basic principle is producing heat or plasmat oi gnite energeticm aterials under the stimulation of electric energy, are one of the most important ignition components manufacturedb ym icroelectronics integrationt echnology,a nd has been widely employed in recent years [1][2][3].I ti sa lso conceivable to lower SCB ignitionv oltage by focusingo nt he core technology development of MEMS fuse, that is, to research and develop micro-energy SCB.N evertheless, SCB with multiple ignition compositions is entirely different in ignitionv oltage and current signal,w hich has prompted substantial research on firing sensitivity [4][5][6].In 2002,Y ang et al. studied the ignition characteristics of lead styphnate and lead azide, and results revealed that compared with lead styphnate, lead azide got ah igher reaction rate, which shortened the total ignitione lapsed time of ignition compositions.H owever,t he authors did not achieve deep analysis of the reaction mechanism [7].Z hu et al. studied SCB ignition characteristics under electrostatic discharge stimulation [8].T he breakthrough from conventional energetic compositions to nanoscale energetic mixtures has dramatically enhanced energy release rate and firing sensitivity,t hence, nanoenergetics are possiblya vailablef or use on SCB. Many studies have shown that the criticali gnition voltage and threshold energy for nanoenergetics are considerably smaller [9][10][11][12].A dditionally,t he possibility of SCB igniting HMX and PETN has also been studied [13][14][15], but the initiating voltage is more than 1kV, which is not conducive to the miniaturization of electric circuit.To find out ignition compositions that can be ignited by SCB and provideb asis for pyrotechnicss election,t he ignition characteristics of SCBs with different ignition compositions were studied and analyzed. With the stimulation of 10 mFt antalumc apacitor discharge, the voltage and current signals under different stimulations were detected with the digital oscilloscope, then were processed;i na ddition, the reaction mechanism ignition characteristics was analyzed. The criticali gnition voltages of different pyrotechnics weret ested byt he Neyer-D optimals ensitivity test method to analyze firings ensitivity,w hich can provide certain evidencef or subsequent pyrotechnics selection. 2E xperimental Section Test SamplesSCB manufacture is at ypicalM EMS microelectronics technology,i nvolving the procedures of polysilicon vapor deposition on am onocrystalline silicon substrate, doping phosphorus atoms of high concentrations on the polycrystalline silicon, etching the bridge,s teaming metalized solder, etching welded panel, and scribing. The SCB sample usedi n the test has ac oncentration of 7.7 10 19 phosphorus atoms per cubic centimeter,w ith dimensions of 100 40 mm, thickness of 2 mm, and average resistance of 8.28 W.T he sample is shown in Figure 1, including the diagram of bridge area shown in Figure 1(a) and am icroscope image of the bridgea rea shown...

Aerospace missions require that pyrotechnic compositions are able to withstand 180 °C. Therefore, this paper studies the thermal stability and output performance of boron/potassium nitrate (abbreviated BPN) used in pyrotechnic devices. Firstly, differential scanning calorimetry (DSC) and thermogravimetric (TG) tests are used to analyze the thermal reaction process of KNO3, boron, and BPN to qualitatively judge their thermal stability. Then, apparent morphology analysis, component analysis, and the p-t curve test, which is the closed bomb test to measure the output power of the pyrotechnic composition, are carried out with BPN samples before and after the high-temperature test to verify BPN stability at 180 °C. The weight change of boron powder caused by chemical reactions occurs above 500 °C. When the temperature is lower than the peak exothermic temperature of decomposition, no obvious chemical reaction occurs with KNO3, and only physical changes (crystal transformation and melting) occur. Combined with a verification test at 180 °C for two days, it is concluded that boron and KNO3 components are stable at 180 °C. With an increase in boron content, the thermal stability of BPN is improved, with the best performance achieved when the ratio is 25:75 (B:KNO3). BPN samples without binder have the best thermal stability. In a test at 180 °C for five days, the binder affects the weight loss and p-t curve of BPN, and BPN with fluororubber binder is better than BPN with unsaturated polyester binder.

In the present study, Rhododendron rex soil from Jiaozishan national nature reserve and Xiaobaicaoling in Yunnan province of China was selected as the research object. Physicochemical properties and high-throughput sequencing techniques were used to analyze soil nutrients and microbial diversity to explore the soil nutrients and microbial community characteristics of Rhododendron rex in central Yunnan, and provide theoretical reference for future research on ex-situ conservation, bionic cultivation and artificial propagation of Rhododendron rex. Results showed that the Rhododendron rex soil in central Yunnan was acidic, and the contents of various nutrients in the soil were high and correlated with each other. The abundance of fungi was higher than that of bacteria, while the diversity of bacteria was higher than that of fungi. There was a correlation between soil nutrients and microbial community characteristics. The dominant phyla of soil bacteria were Acidobacteria, Proteobacteria and Actinobacteria, and the sum of relative abundance was 78.97%. The dominant phyla of fungi were Ascomycota and Basidiomycota, and the sum of relative abundance was 94.89%.

No abstract