Explosive synchronization in network of mobile oscillators

Recently, the explosive synchronization (ES) has attracted great interests. Motivated by the recent dynamic framework of complex network, we focus on the network of mobile oscillators and study synchronization phenomenon. The local synchronous order parameter of the neighbors of the oscillator is used as the controllable variable to adjust the coupling strength of the oscillator. Hence, it can be seen as a kind of adaptive strategy. By numerical simulation, we find that ES can be observed in the dynamic network of mobile oscillators, accompanying with hysteresis loop, as the coupling strength increases gradually. It is found that the critical value of coupling strength and hysteresis loop width is affected by the natural frequency distribution and the number of neighbors the oscillator owning. It can be deduced that ES will be motivated by increasing the number of oscillators in the network. Meanwhile, our results are feasible to different natural frequency distributions, such as Lorentzian, Gaussian power-law, and Rayleigh distribution, whether it is symmetric or not.     

防爆舱设计及抗爆炸冲击波超压试验研究

为了满足某驾驶操作舱对爆炸冲击波的防护,设计了防爆舱结构,选用了多种防护材料,数值计算了爆炸参数和结构强度,完成了防爆舱在距离爆炸点9 m处12 kg三硝基甲苯(trinitrotoluene, TNT)裸装药的爆炸试验,重点测试了防爆驾驶舱内外的声压、内部噪声及操作人员座椅处的3个方向的振动加速度曲线。结果表明:舱内脉冲噪声峰值最大为135.1 dB;压力峰值为882.5 Pa,持续时间约为1 472 ms;座椅处3个方向的振动加速度最大为15.41g,持续时间为0.23 s;均在相关标准安全限制内,满足对等效重量为12 kg TNT及以下爆炸物在9 m处的爆炸冲击波的有效防护,验证了该防爆舱的可靠和安全。     

Radiation-based security

The problems presented in different security areas are varied but the solutions that have been offered are generally based upon the same principles. Employing radiation to locate and identify explosives or contraband has been most obvious at airports but other locations are now receiving equal attention. Neutron and X-ray interrogation are the systems most frequently employed. However, the more recently developed approaches such as multi-view dual-energy imaging and the use of high-speed diffraction measurements are the most likely systems to become widely available. This review looks briefly at the neutron and X-ray based systems that have been developed indicating their mode of operation and their advantages and disadvantages. It then summarizes the current state-of-the-art. The paper finishes by looking in some detail at one of the most promising areas of development—in-line diffraction measurements.     

[Mn(CHZ)3](ClO4)2的制备、晶体结构和应用研究

碳酰肼[1]分子中有5个含孤电子对原子, 因此可作为单齿或多齿配体与多种金属离子配位[2～3]; 而且, 碳酰肼是肼的衍生物, 具有强还原性, 可用作含能材料的组分, 所以, 其配合物在含能材料领域引起了极大的关注[3～9]. 通过高氯酸锰水溶液和碳酰肼水溶液直接化合的方法得到了标题化合物的单晶, 测定了其晶体结构, 并研究了其爆炸性能.     

雷酸家族史话

This article describes an introduction of fulminic acid. The story of fulminic acid and fulminates was introduced from the discovery of mercury fulminate to the concept of isomers and the success of Alfred Nobel in the development of explosives. This process provides a good example of integrating science and technology.     

Selection of phage displayed peptides for the detection of 2,4,6-trinitrotoluene in seawater

We have selected for phage displayed peptides that showed specific binding to a 2,4,6-trinitrotoluene (TNT) derivative, 2,4,6-trinitrobenzene (TNB) in environmentally relevant conditions, and have integrated the selected phage into a continuous flow immunosensor platform for the detection of TNT. A library of 12 random amino acid peptides (12-mers) displayed on phage was panned against TNB coupled to the protein bovine serum albumin (BSA) in a solution of artificial seawater. Eight phage clones, seven of which share an identical amino acid sequence, bound selectively to TNB-BSA in artificial seawater as judged by enzyme-linked immunosorbent assay (ELISA). Addition of TNT, inhibited binding of the phage. Whole phage were labeled with the dye cyanine 5 (Cy5), and incorporated into a flow sensor platform. Labeled phage were loaded onto a TNB-affi-gel packed column, and a reproducible signal, at least five times greater than background, was observed on repeat injections of 10 mg/l TNT dissolved in seawater. This study presents one of the first examples of phage selection in a non-physiological medium, and the first demonstration that dye-labeled phage can be integrated into a continuous flow sensor.     

Extraction and determination of trace amounts of energetic compounds in blood by gas chromatography with electron capture detection (GC/ECD)

This paper describes an efficient and sensitive method for determining five energetic compounds at trace levels (ng/mL) in blood by gas chromatography with electron capture detection (GC/ECD). For seven test concentrations (1-1250 ng/mL), the average recoveries (%) were 104 ± 16, 108 ± 22, 105 ± 14, 100 ± 22 and 108 ± 16 for hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX), hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX), hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), hexahydro-1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and 2,4,6-trinitrotoluene (TNT) (n = 84), respectively. Analysis of DNX and RDX produced lower precision than other energetic compounds. Acetonitrile extracts of blood samples should be analyzed immediately as the test compounds can transform into unknown compounds, which lowered the recovery by 0-45% within 10 days at room temperature (∼20 °C). Maintaining sample extracts at 4 °C decreased loss of test compounds. The method described herein was validated by different analysis teams on different days. Two-way ANOVA indicated that there was no significant difference between analysis teams or days of analysis. The method was successfully employed in the analysis of blood samples from a mouse dosing study involving TNX and RDX.     

Kinetic modeling study of the laser-induced plasma plume of cyclotrimethylenetrinitramine (RDX)

A kinetic model of a laser-induced breakdown spectroscopy (LIBS) plume of cyclotrimethylenetrinitramine (RDX) was developed for the analysis of processes responsible for the LIBS signature of explosives. Air and argon were considered as buffer gases. The model includes a set of processes involving ion chemistry, as well as excitation, ionization, and other processes affecting neutral and ion species. Modeling results show that the overall reaction process can be considered a two-stage process. The first stage corresponds to a fast approach to a quasi-stationary state, while the second stage corresponds to the change of quasi-stationary species concentrations due to the change in temperature. As a result of the two-stage process, the initial mechanism of explosive decomposition is not important in determining its signature in the LIBS measurement time window (1–30 μs). The main processes responsible for generation of excited states for the LIBS emission are electron-excitation impact processes. A mechanism for the appearance of a double peak of the C₂ species concentration in the RDX plasma plume was suggested. Double-peak behavior of the C₂ species was previously experimentally observed during laser ablation of graphite.     

A theoretical study of explosive sensitizers

Quantum chemical calculations at the HF/6-31G^* and B3LYP/6-31G^* levels have been performed on five explosive sensitizers, ethyl nitrate (EN), n-propyl nitrate (NPN), isopropyl nitrate (IPN), 2-ethylhexyl nitrate (EHN) and tetraethylene glycol dinitrate (TEGDN). Theoretical study has made a detailed molecular-level investigation of the title compounds. Based on the Mulliken populations and bond lengths, the fission of the O₂–N₃ can be acceptable reasonably. Charge distribution analysis indicates that the five nitrates produce NO₂ gas during the dissociation of the O₂–N₃ weak bond. We also order the relative thermal stability of five nitrates on the basis of frontier orbital energy (E _HOMO, E _LUMO) and energy gap (ΔE = E _HOMO − E _LUMO).