Flash Lamps as Ignition and Initiation Sources of the VS-2 Pyrotechnic Composition

In the present work it is found that the pyrotechnic composition VS-2 can be initiated with flash lamps IFC-500 and EVIS. VS-2 pyrotechnic composition contains 90% of mercury（Ⅱ） 5-hydrazinotetrazolate perchlorate and 10% of optically transparent copolymer of 2-methyl-5-vinyltetrazole and methacrylic acid （PVMT）. We have found that the flash lamps make it possible to initiate combustion of VS-2 composition with its transition to detonation both in cylindrical charges placed in brass caps of 5 mm diameter and 2 mm high， and film charges with 10 mm×80 mm in size and surface weights of 60 mg·cm^-2 and 90 mg·cm^-2， showing ignition delay times 10 μs and 3 μs， respectively. We also measured detonation velocities for VS-2 composition film charges， which were 4375-4505 m·s^-1 （of the charge being surface mass 60 mg·cm^-2） and 4221-4281 m·s^-1 （of the charge being surface mass 90 mg·cm^-2） and their blasting action on the aluminum plate. The depths of the normal shock wave imprints at the charge-barrier interface were 0.6-0.7 mm （for surface mass of the film charges 60 mg·cm^-2） and 1.2-1.3 mm （for surface mass of the film charges 90 mg·cm^-2）.     

Advantages and disadvantages of nuclear reactions used in reactors or cyclotrons,in addition to a theoretical study based on photodisintegration on natural indium for 111Ag production

Production routes were recorded on available reactions for ¹¹¹Ag production from nuclear reactors or cyclotrons using a natural palladium target based on ¹¹⁰Pd（n, γ） and ¹¹⁰pd（d, n） reactions, respectively.^natCd（γ,x） based on ¹¹⁰Cd（γ, p） has also been studied as a prospective reaction for the production of ¹¹¹Ag. Unfortunately, these nuclear reactions are difficult to utilize because, in some cases, they reduce the specific activi...     

Fe3O4-carbon spheres core–shell supported palladium nanoparticles: A robust and recyclable catalyst for suzuki coupling reaction

Suzuki-Miyaura (S-M) is regarded the most powerful way for synthesis biaryls, triaryls, or incorporating of substituted aryl moieties in organic preparation by the cross-coupling of aryl boronic acid with aryl halides using the Pd catalyst. This work reports the combining of the hydrothermal and microwave-assisted protocol to convert the glucose to magnetic carbon spheres (Fe₃O₄-CSPs) decorated with Pd nanoparticles (NPs) as the catalyst for Suzuki-Miyaura cross-coupling reactions. The physicochemical properties in the produced composite were examined using FESEM, HRTEM, nitrogen isotherms, Raman spectroscopy, FTIR, XPS, and XRD. The as-fabricated composite Pd/Fe₃O₄-CSPs is mostly spherical with a core–shell structure and possesses a great surface area of 253.2 m²·g^-1. Its catalytic performance demonstrates that the composite has excellent stability and high tolerance Suzuki-Miyaura cross-coupling reactions in 30 min at 80 ℃. Both activated and deactivated aryl halides provided excellent yield. The as-fabricated catalyst was recycled for up to four catalytic cycles without a substantial decline in performance. Moreover, this research offers a facile roadmap for synthesizing Pd/Fe₃O₄-CSPs composites and promoting the practical implementation of Pd/Fe₃O₄-CSPs catalysts for organic transformation processes.     

Methods and mechanisms for uniformly refining deformed mixed and coarse grains inside a solution-treated Ni-based superalloy by two-stage heat treatment

The uniform refinement mechanisms and methods of deformed mixed and coarse grains inside a solution-treatment Ni-based superalloy during two-stage annealing treatment have been investigated.The two-stage heat treatment experiments include an aging annealing treatment(AT)and a subsequent recrystallization annealing treatment(RT).The object of AT is to precipitate some δ phases and consume part of storage energy to inhibit the grain growth during RT,while the RT is to refine mixed and coarse grains by recrystallization.It can be found that the recrystallization grains will quickly grow up to a large size when the AT time is too low or the RT temperature is too high,while the deformed coarse grains cannot be eliminated when the AT time is too long or the RT temperature is too low.In addition,the mixed microstructure composed of some abnormal coarse recrystallization grains(ACRGs)and a large number of fine grains can be observed in the annealed specimen when the AT time is 3 h and RT tem-perature is 980℃.The phenomenon attributes to the uneven distribution of δ phase resulted from the heterogeneous deformation energy when the AT time is too short.In the regions with a large number of δ phases,the recrystallization nucleation rate is promoted and the growth of grains is limited,which results in fine grains.However,in the regions with few δ phases,the recrystallization grains around grain boundaries can easily grow up,and the new recrystallization nucleus is difficult to form inside grain,which leads to ACRGs.Thus,in order to obtain uniform and fine annealed microstructure,it is a prereq-uisite to precipitate even-distributed δ phase by choosing a suitable AT time,such as 12 h.Moreover,a relative high RT temperature is also needed to promote the recrystallization nucleation around δ phase.The optimal annealing parameters range for uniformly refining mixed crystal can be summarized as:900℃×12 h+990℃×(40-60 min)and 900℃×12 h+1000℃×(10-15 min).     

Protection and control of microgrids usingdynamic state estimation

High penetration of Converter Interfaced Generations (CIGs) presents challenges in both microgrid (μGrid) circuit and other system with CIG resources, such as wind farms and PV plants. Specifically, protection challenges are mainly brought by the insufficient separation between fault and load currents, especially for μGrids in islanded operation, and the short connection length in μGrids. In addition, CIG resources exhibit limited inertia and weak coupling to any rotating machinery, which can result in large transients during disturbances. To address the above challenges, this paper proposes a Dynamic State Estimation (DSE) based algorithm for protection and control of systems with substantial CIG resources such as a μGrid. It requires a high-fidelity dynamic model and time domain (sampled value) measurements. For μGrid circuit protection, the algorithm dependably and securely detects internal faults by checking the consistency between the circuit model and available measurements. For CIG control, the algorithm estimates the frequency at other parts of a μGrid using CIG local information only and then utilizes it to provide supplementary feedback control. Simulation results prove that DSE based protection algorithm detects internal faults faster, ignores external faults and has improved sensitivity towards high impedance faults when compared to conventional protection methods. DSE based CIG control scheme also minimizes output oscillation and transient during system disturbances.     

ZrCuAlNi系大块金属玻璃的非晶形成能力、热学和力学性能（英文）

分析ZrCuAlNi系大块金属玻璃的非晶形成能力、热学和力学性能。运用密实堆积和动态脆性指数模型从理论上确定合金的成分。采用铜模吸铸法在氩气保护下制备圆柱形和圆锥形铸锭。用X射线衍射表征圆锥形铸锭以便确定非晶结构。结果表明:两种合金的临界非晶直径为3 mm。用差示扫描量热法(DSC)分析其热行为,加热速率分别为0.5、0.67和0.83 K/s。γ参数、过冷液相区ΔT_x和约化玻璃转变温度T_(rg)等这些实验所得的参数均表明其具有高的非晶形成能力。非晶成分显示其脆性指数为40。合金的压缩试验采用的应变速率为0.016 s~(-1),得到弹性模量约为83 GPa,总应变约为5%,屈服强度为1.6 GPa,硬度为4 GPa。运用密实堆积和动态脆性指数模拟可以预测ZrCuAlNi系合金的非晶形成成分。     

Easy access to pharmaceutically relevant heterocycles by catalytic reactions involving α-imino gold carbene intermediates

This review summarizes recent advances in the field of gold-catalyzed synthesis of pharmaceutically relevant aza-heterocycles via in situ generated α-imino gold carbene complexes as intermediates.     

由刨花金属短纤维制备技术用金属纱线

目前,德国纺织机械和高性能材料技术研究所(ITM)正对刨花金属短纤维纺制纱线的工艺过程进行广泛的调查研究。为顺利纺纱,必须考虑这类纤维的高耐磨性、高脆性和高刚性等特性,以及它们较高的塑性变形和粘滑运动倾向。基于传统成纱工艺,开发出以刨花金属短纤维为原料,经拉伸断裂、牵伸和纺纱过程制备纯金属纱线的纺纱工艺链。基于目前的研究,由刨花金属短纤维制备纯金属纱线的可行性已得以证实。所得金属纤维在高性能、低成本技术应用方面具有较高的潜力。