One-Pot Synthesis,Crystal Structure,and Thermal Decomposition Behavior of 1,1ʹ-Diamino-4,4ʹ,5,5ʹ-Tetranitro-2,2ʹ-Biimidazole

1,1?-Diamino-4,4?,5,5?-tetranitro-2,2?-biimidazole (DATNBI) was synthesized, by employing one-pot facile method, from 4,4?,5,5?-tetranitro-2,2?-biimidazole. The crystal structure was determined by X-ray diffraction for the first time. DATNBI crystallized in monoclinic system P2₁/c, with a crystal density of 1.934 g cm^?3 at 293(2) K and 2.019 g cm^?3 at 130(2) K, respectively. Its crystal parameters at 293 K are a = 4.8833(15) Å, b = 6.960(2) Å, c = 6.928(4) Å, α = γ = 90°, β = 93.418(6)°, V = 591.1(3) ?³, Z = 2, μ = 0.178 mm^?1, and F(000) = 348. The thermal stability and non-isothermal kinetics of DATNBI were studied by differential scanning calorimeter (DSC) with heating rates of 5, 10, 15, and 20 K min^?1. The apparent activation energy (E_a) at the first decomposition peak calculated by Kissinger, Ozawa, and Starink equations were 85.50, 89.67, and 86.10 kJ mol^?1, respectively. For the second peak, these were 116.49, 119.82, and 117.45 kJ mol^?1, respectively, with individual pre-exponential factors lnA = 18.40 s^?1 and lnA = 25.11 s^?1. The thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR) analysis of thermal decomposition products reveals that the main decomposition gas products are H₂O, N₂O, CO₂, and NO₂. Based on the new crystalline densities, the detonation velocity and pressure predicted by EXPLO5 are 9062 m s^?1 and 36.4 GPa, respectively.     

Palladium and Copper Cocatalyzed Intermolecular Cyclization Reaction: Synthesis of 5‐Aminopyrazole Derivatives

A novel and efficient palladium and copper co‐catalyzed intermolecular cyclization of acetonitriles with hydrazones has been developed for the synthesis of 5‐aminopyrazoles through C C and C N bond formation. The reaction has the advantages of easily available starting materials, simple manipulation and mild reaction conditions. The reaction involving various substituted acetonitriles and hydrazones proceeds smoothly and 5‐aminopyrazoles are synthesized in good yields. In contrast to the aliphatic and heteroaromatic substrates, the aromatic substrates tend to have a higher degree of reactivity.

     

A Novel LaAlO3 Perovskite with Large Surface Area Supported Ni-Based Catalyst for Methane Dry Reforming

Catalysis Letters - In this paper, the LaAlO3 perovskite with large specific surface area and abundant surface oxygen vacancies is prepared by the hard template method, on which Ni metal...     

Numerical modeling of the 2008 Wenchuan earthquake-triggered Niumiangou landslide considering effects of pore-water pressure

Bulletin of Engineering Geology and the Environment - Ring-shear experiments are commonly conducted to analyze the kinematic mechanisms of landslides triggered by earthquakes, particularly for...     

Fabrication of shish-kebab-structured carbon nanotube/poly(ε-caprolactone) composite nanofibers for potential tissue engineering applications

The electrospinning process was applied to fabricate the nanofibers of biodegradable poly(ε-caprolactone)(PCL) in which different contents of multiwalled carbon nanotubes(MWCNTs) were embedded. Afterward,the electrospun nanofibers were successfully decorated with shish-kebab structure via a self-induced crystallization technique. The topographical features and the mechanical properties of the composite scaffolds were characterized,and the biocompatibility of the material was assessed by using human osteogenic sarcoma osteoblasts(MG-63 cells). The carbon nanotube(CNT) concentration is found to affect the fiber diameter and mechanical properties of electrospun nanofibers and the periodic distance of the shish-kebab architecture. Cellular attachment and proliferation assays reveal that 0.5 wt% CNT-embedded PCL scaffold shows enhanced biocompatibility with MG-63 cells than their counterparts made of neat PCL, and the collagen-like nanotopology provided by the shish-kebab structure further facilitates the cell adhesion and proliferation. The superior interactions between cells and scaffolds demonstrate that the shish-kebab-structured CNTs/PCL nanofibers may be promising candidate for tissue engineering scaffold application.     

Chemical synthesis of SmCo_5/Co magnetic nanocomposites

A three-step chemical synthesis of SmCo_5/Co nanocomposites was developed. Firstly, the Co-Sm(OH)_3-Ca(OH)_2 precursors were prepared by co-precipitation.Secondly, SmCo_5 particles were obtained by reductive annealing of the precursors. At last, the SmCo_5/Co nanocomposites were achieved by chemical deposition based on SmCo_5 particles. The SmCo_5/Co nanocomposites contain hard magnetic phase of SmCo_5 with about 100 nm in size and soft magnetic phase of Co with about 8 nm in size,exhibiting independent two-phase structure without alloying. Compared to that of single-phase SmCo_5 particles, the saturation magnetization of SmCo_5/Co nanocomposites is increased by 27.5%. The synthesis provides a new route to fabricate SmCo-based nanocomposites.     

Quench Sensitivity of AA7N01 Alloy Used for High-Speed Train Body Structure

JOM - The quench sensitivity of AA7N01 aluminum alloy used for high-speed train body structure was investigated by end-quenching test, time–temperature-transformation curves simulation,...     

Preface

Evolutionary Algorithms(EAs)mimicking the principles of natural evolution can be used as powerful search and optimization methods.These Evolutionary Optimization methods are superior to traditional optimization methods especially in situations where gradient information is not readily available.EAs are generic and robust optimization methods since they do not make any assumption about the underlying search space.This is clearly evident by the success of EAs in a diverse range of real-world applications.T...     

化工企业关键设备评估方法的研究及应用

企业关键设备的评估涉及到维修策略选择的优劣,针对化工企业设备运行要求安全性高、对环境影响大、生产工艺连续等特点,构建了化工企业关键设备评估指标体系,运用模糊综合评价算法评估出关键设备,根据其关键性的不同等级采取不同的维修模式,并以某化工企业为对象进行应用验证。     

严重事故下吸湿性气溶胶的自然去除研究

反应堆发生严重事故时,堆芯释放出的吸湿性气溶胶会在潮湿的安全壳内增大,从而影响其自然去除过程。本文理论推导了吸湿性气溶胶的增大模型并通过多种方法对其进行了验证。模型计算结果表明,气溶胶的增大过程由于受到溶解度的限制而存在临界湿度值,在该临界值以下时气溶胶不发生吸湿,但这未被其他严重事故分析程序所考虑。同时,基于某三代先进压水堆的特定严重事故工况,本文分析了干颗粒半径及湿度对气溶胶的平衡半径和自然去除系数的影响。结果表明:气溶胶的自然去除系数随干颗粒半径的增大将先减小后增加,并在1μm时达到最小值;相同湿度下,干颗粒半径对气溶胶半径的最大增大比例的影响不大;湿度的增加对不同干颗粒半径气溶胶去除系数的影响不同。