Crystallography and Structure–Property Relationships of 2,2″,4,4′,4″,6,6′,6″‐Octanitro‐1,1′ : 3′,1″‐Terphenyl (ONT)

An X‐ray crystallographic study of 2,2″,4,4′,4″,6,6′,6″‐octanitro‐1,1′ : 3′,1″‐terphenyl (ONT) has been carried out. The dihedral angles between benzene rings vary from 84.9° to 89.4°. Nonbinding interatomic distances of oxygen atoms inside all the nitro groups are shorter than the intermolecular contact radii for oxygen. On the basis of the DFT B3LYP/6‐31(d, p) method it was found that the difference between the X‐ray structure in the solid phase and DFT result for the gas phase is 98 kJ mol⁻¹, and the bearer of the highest initiation reactivity of the ONT molecule in the solid phase should be the nitro group at 4″‐position, in contrast to those at 4′‐ or 6′‐position that play this role in the isolated molecule. It has been stated that the nitro groups at the reaction centers of the ONT molecule are relatively well specified by their ¹⁵N NMR chemical shifts.     

不同压缩算法性能的研究

移动通信网络中，建立一次多媒体会话通常需要数十秒钟的时间。通过对信令消息的压缩可以有效地减少所需时延，改善服务质量。文章先后使用了LZ77、LZW和Deflate压缩算法对因特网协议多媒体子系统中的会话发起协议信令消息的压缩进行了研究。仿真结果显示：Deflate算法的压缩性能最好，不使用辞典时压缩率可以达到30％，使用辞典时压缩率可以达到50％以上；接着是LZW算法，而LZ77算法的压缩性能最差。     

钝感弹药及安全可靠起爆新技术

叙述了国外钝感弹药发展概况,提出了几种钝感弹药起爆模型。     

On the Mechanism of Efficiency of Lead Azide

The mechanism of superior efficiency of lead azide (LA) in comparison with mercury fulminate (MF) is not understood. Indeed, both primary explosives have quite close detonation velocities and result in a large amount of condensed lead (Pb) and mercury (Hg), respectively. We explore an idea that the high efficiency of LA is due to the fact that the boiling point of lead markedly exceeds that of Hg. Then the products of LA in the detonation reaction zone could contain liquid Pb droplets, while MF products are gaseous. These lead droplets could violently impact the acceptor charge and favor its initiation. The plate dent studies of high explosives (HE) heavily loaded by metal particles provide an indirect support to the proposed mechanism. To check this hypothesis we numerically studied the donor/acceptor problem, where the donor is made of HE loaded with the inert metal particles. Pressure, velocity, and temperature relaxations of particles are taken into account. The model agrees with the experimental effect of metal addition on HE performance. However, the calculations show that the effect of particle penetration into the acceptor is late and weak in comparison with the effect of primary shock induced in the acceptor. Thus, the above hypothesis could not guide the development of green substitutes of LA. Hybrid mixtures of a nanothermite with a high explosive seem to be more promising for this purpose. A simple explanation is proposed for the superior triggering capacity of LA.     

爆炸逻辑网络起爆控制系统研究

介绍了采用微处理器控制爆炸逻辑网络起爆的方法．初步探讨了该技术的发展和应用。     

A Component-Based Conference Control Model and Implementation for Loosely Coupled Sessions

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电子雷管起爆法的安全技术探讨

针对我国电子雷管起爆安全技术及措施目前尚未有一个完整的标准和规程,介绍了电子雷管的结构原理,并针对隆芯1号数码电子雷管及其起爆系统进行了安全技术方面的探讨,对电子雷管起爆法在爆破工程中安全技术的制定提出了一些见解。可为使用电子雷管的爆破作业人员提供参考。     

基于身份的SIP认证与密钥协商机制研究

对SIP中的安全威胁和已有安全机制进行了分析,提出一种基于身份的SIP认证与密钥协商方案,通过3次交互实现双向认证,并在该过程中完成密钥协商.方案不需要公钥证书,以用户身份标识作为公钥,降低了计算复杂度和通信开销,保证了SIP消息传递过程中的完整性和真实性.     

Fretting fatigue life prediction using the extended finite element method

In this work, an efficient procedure to predict fatigue lives in fretting fatigue problems is presented. This is accomplished by means of a combined initiation-propagation approach in which the extended finite element method (X-FEM) is used. The procedure is verified by modelling several fretting fatigue tests available in the literature. The application of the X-FEM enables to numerically evaluate the stress intensity factors (SIFs) for cracks of different lengths emanating at the end of the contact zone and to estimate the propagation life corresponding to each of the tests. This propagation life is combined with the initiation life calculated using a multiaxial fatigue criterion (Fatemi-Socie). The predicted lives are then compared with the reported experimental lives, showing that the consideration of the crack-contact interaction through the numerical models tends to improve the life estimation when compared with a fully analytical approach. The procedure can be applied to more general fretting problems for which analytical solutions are not available.     

螺旋缝焊管静水压爆破试验分析

通过对螺旋缝焊管进行静水压爆破试验,得出钢管的屈服压力、最大压力值和爆破压力值,验证钢管成型和焊接工艺的合理性,为管线的设计单位和用户提供参考依据.介绍了螺旋缝焊管静水压爆破试验所用的装置;分析了爆破试验管的管内承压状况、爆破试验过程以及不同起爆点的由来,并以X65钢级Φ813 mm×9.5mm螺旋缝焊管的爆破试验进行...