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.     

Properties and carbonization behavior of asphalt modified with the THF-soluble fraction of a coal liquefaction residue

This study focuses on the effects of the tetrahydrofuran-soluble fraction of direct coal liquefaction residue as a modifier to modify asphalt with formaldehyde. The properties and carbonization behavior of matrix asphalt and the modified asphalts were studied. The results indicate that the ductility properties of modified asphalts have been effectively improved. The morphology of modified asphalts without the addition of formaldehyde is a set of uniform distribution point, and it is converted from linear distribution to clustered distribution observed in fluorescence microscope images with the increase of the adding amount of formaldehyde.     

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.

     

Efficient Catalyst for Both Suzuki and Heck Cross‐Coupling Reactions: Synthesis and Catalytic Behaviour of Geometry‐ Constrained Iminopyridylpalladium Chlorides

A series of geometry‐constrained iminopyridyl‐palladium chlorides were synthesized and characterized. These phosphine‐free palladium complexes were explored for their catalytic activities in both Suzuki and Heck cross‐coupling reactions, achieving turnover numbers as high as 10⁶ towards various aryl bromides, even those containing various functionalities. In addition, the influence of substituents with steric and electronic factors was reflected by the differences observed in their activities.

     

磷化工"双废"联用工艺研究

以磷化工"双废"——磷石膏、磷尾矿为原料,通过硫酸循环酸浸磷尾矿,经盐酸分解磷尾矿、碳化磷石膏、转晶、酸化、析钙、析磷、浓缩、析镁等过程,得到了转化率为96.94％ 的CaCO 3,CaO质量分数为23.38％ 的二水石膏,MgO质量分数为8.27％、P2O5质量分数为23.89％、氮质量分数为6.83％ 的氮镁磷肥,氮质量分数为23.76％ 的氯化铵以及M g O质量分数为30.04％ 的碳酸镁等,所得产品均符合工业应用要求.讨论了循环酸浸过程中离子浓度的变化情况,为联合处理磷石膏、磷尾矿提供了新思路.     

Synthesis of Polymer Nanospheres Conjugated Ce (IV) Complexes for Constructing Double Antibacterial Centers

Journal of Inorganic and Organometallic Polymers and Materials - The antimicrobial materials are rapidly emerging as a primary component in mitigation of bacterial pathogens, and functional...     

From Directive to Legislation,from Separation to Integration: Rural Planning Evolution Since the Founding of New China

Since the founding of new China in 1949, rural development in China has experienced three periods, which have been first the collective economy, second the household contract responsibility system, and third the chronological coordination of the urban and rural. Meanwhile, there are three types of statutory planning that guide rural construction and management in China, i.e., land use planning, land consolidation planning, and village and town planning. This paper summarizes their different characteristics in the three periods respectively. Firstly, the period of the collective economy from 1949 to 1978 is the embryonic stage of rural planning, during which land use planning was just introduced from abroad, while land consolidation planning and village and town planning had not yet been formed. In this period, rural planning had a strong planned economy feature. The following period of the household contract responsibility system from 1978 to 2003 is the growth stage of rural planning, during which all three types of planning developed their independent preparation, regulation, and management systems. In the period of urban and rural coordination from 2003 to the present, there has been a trend towards urban and rural integration and joint development among three types of planning. Based on the rural development history in China since 1949, this paper concludes that the three types of statutory planning have transformed in adapting to China's national conditions toward a more standardized, legislated, and integrated mode.     

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...     

Stability analysis of deep-buried hard rock underground laboratories based on stereophotogrammetry and discontinuity identification

Bulletin of Engineering Geology and the Environment - In a tunnel, instabilities in the surrounding rock mostly occur within the sidewalls and crown. After acquiring the rock mass structure, a...     

As-cast microstructure of Al-Zn-Mg-Cu-Zr alloy containing trace amount of Sc

It has been reported that the element scandium(Sc) is the most effective modificator which can significantly refine the grain size, prohibit recrystallization process and increase the strength. Adding trace of Sc in 7000 series aluminum alloys is considered to be an effective way to modify its micros tructure and promote mechanical properties. In order to study the effect of Sc element on ascast microstructure of Al-Zn-Mg-Cu-Zr alloy, ingots containing different amounts of Sc were prepared by ferrous-mold cast. Microstructures were characterized by means of differential scanning calorimeter(DSC), X-ray diffraction(XRD), optical microscope(OM) and scanning electrical microscope(SEM). The results indicate that when the Sc level exceeds a critical concentration,Al_3(Sc,Zr) primary phase would form in the melt and act as an efficient nucleant, resulting in very refined grain and an equiaxed grain structure. Sc element reduces the number of eutectic phases formed during solidification,coupled with an increase in the concentration of major alloying elements retained in the solute. This behavior suggests possible benefits in improving the integrated properties of terminal products.