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21.
In this study, 40CrMnSiB steel cylindrical shells were tempered at 350, 500 and 600 ℃ to study the effect of tempering temperature on the dynamic process of expansion and fracture of the metal shell. A mid-explosion recovery experiment for the metal cylinder under internal explosive loading was designed, and the wreckage of the casings at the intermediate phase was obtained. The effects of different tempering temperatures on the macroscopic and microscopic fracture characteristics of 40CrMnSiB steel were studied. The influence of tempering temperatures on the fracture characteristic parameters of the recovered wreckage were measured and analyzed, including the circumferential divide size, the thick-ness and the number of the circumferential divisions. The results show that as the tempering temper-ature was increased from 350 to 600 ℃, at first, the degree of fragmentation and the fracture characteristic parameters of the recovered wreckage changed significantly and then became essentially consistent. Scanning electron microscopy analysis revealed flow-like structure characteristics caused by adiabatic shear on different fracture surfaces. At the detonation initiation end of the casing, fracturing was formed by tearing along the crack, which existed a distance from the initiation end and propagated along the axis direction. In contrast, the fracturing near the middle position consists of a plurality of radial shear fracture units. The amount of alloy carbide that was precipitated during the tempering process increased continuously with tempering temperature, leading to an increasing number of spherical carbide particles scattered around the fracture surface.  相似文献   
22.
在突发事件的应急处置过程中,思想政治教育通过对处于突发事件中的人们进行心理救助、情绪调控、挫折调适以及心理引导,发挥心理调适功能。应急处置突发事件的思想政治教育心理调适机制包括:心理干预机制、情绪调控机制、挫折调适机制及心理引导机制。  相似文献   
23.
为了有效抑制油气爆炸传播,根据抑制爆炸的特殊需要,研究了冷气溶胶抑爆剂新配方,解决了超细冷气溶胶易于团聚这一技术难题。首先采用超音速气流粉碎新技术成功研制了超细冷气溶胶抑爆剂,平均粒度小于5μm。其次通过表面复合改性显著提高了超细粉体的稳定性和分散性,表面改性剂用量的临界质量分数为0.5%。参数测试和灭火实验表明新型冷气溶胶对火焰有强抑制、强窒息作用和对热辐射的遮隔、冷却作用,具有较强的油气抑爆灭火效能;中/小型油料火的灭火时间小于1.6s,抑爆剂用量低于60g/m^3。  相似文献   
24.
我国现行宪法第45条规定:国家和社会保障残废军人的生活,抚恤烈士家属,优待军人家属。因此,军人优抚权属于宪法权利的范畴,军人享有优抚的宪法权利;国家和社会是法定的义务主体,必须依法履行法定义务。  相似文献   
25.
古建筑防火新技术研究   总被引:1,自引:0,他引:1  
阐述了古建筑火灾的危险性,并从本质安全的角度研究了古建筑中木材、纤维织物的阻燃措施。指出木材的阻燃处理方法通常采用物理和化学方法,而化学方法可采用表面涂覆、浸渍处理、化学改性三种方法;纤维织物阻燃处理采用共聚阻燃改性、共混阻燃改性、阻燃后整理、接枝共聚、皮芯型复合纺丝等方法。可以根据具体情况选用合适的阻燃处理方法,从而达到降低材料可燃性的目的,大大提高古建筑的火灾风险等级。  相似文献   
26.
曹亭  张相炎 《指挥控制与仿真》2012,34(5):115-118,133
制退机的性能好坏直接关系到火炮作战效能的发挥。针对目前装备保障方式大多停留在维修层面而理论研究不够深入的实际,对节制环磨损故障的机理进行分析。以某型火炮短节制杆式制退复进机为对象,利用MATLAB数值计算平台,编程仿真节制环磨损故障对后坐的影响。同时探讨了故障后对火炮的处理方案。研究表明,节制环磨损对后坐诸元都将产生不同影响,针对影响的程度可制定相应的故障处理方案。仿真模拟和方案探讨对装备保障工作具有参考意义。  相似文献   
27.
聚类方法在污水处理软测量中的应用机理研究   总被引:1,自引:0,他引:1  
通过对污水处理过程建立多神经网络模型的可行性研究以及对活性污泥微生物的生长繁殖规律分析,得出在污水处理工程中采用基于聚类方法的多神经网络建模的理论依据,试验表明多神经网络的扩散常数同类半径相当接近,预测精度较高,证实了聚类分析的正确性.分析了可能影响模型精度的原因,指出采用在线实时算法是未来的研究方向.  相似文献   
28.
We consider a design problem for wastewater treatment systems that considers uncertainty in pollutant concentration levels at water sources. The goal is to optimize the selection of treatment technologies and pipeline connections, so that treated wastewater can achieve specified effluents discharge limits as well as possible. We propose a new two-stage model to optimize a set of guarantee levels, that is, the maximum concentration level of source pollutants for which treated wastewater can be compliant with discharge limits. In the first stage, treatment technologies and pipeline connections are selected. In the second stage, when pollutant concentration levels are revealed, wastewater distribution and mixing are determined. A key attractiveness of the proposed guarantee rate optimization model is that it can be simplified into a single-stage mixed-integer linear program. In our numerical experiments based on real-world pollutants data, the guarantee rate model demonstrates its advantages in terms of computational efficiency, scalability and solution quality, compared with the standard probability maximization model. Finally, the methodology proposed in this paper can also be applied to other two-stage problems under uncertainty with similar uncertainty characteristics.  相似文献   
29.
卢新焵 《国防科技大学学报》1988,10(4):85-91 ,119
文中研究了临界点间热处理对Welten-80p钢、20CrMnSi钢及20CrmnSiNi2A钢低温韧性的影响。结果表明:与常规热处理相比,临界点间淬火及回火钢的a_k值提高了1~3倍,冷脆转变温度降低了54℃。临界点间热处理是提高结构钢低温韧性的有效措施。  相似文献   
30.
简述了我国合同制消防队伍的现状,全面总结了目前我国合同制消防队伍存在的问题,深刻分析了阻碍合同制消防队伍稳定发展的主要因素,并重点提出了针对性的改进措施,为我国合同制消防队伍健康有序发展提供了有益借鉴。  相似文献   
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