激励器结构参数对合成射流影响的试验研究

为了设计高性能的合成射流激励器,实验采用热线风速仪测量激励器出口的流动速度,对不同大小激励器、不同出口形状激励器、单 双膜激励器以及金属振动膜处于不同装配受压状态下的激励器分别进行了试验。实验结果显示:激励器的结构决定了合成射流激励器的性能;激励器出口射流平均速度除了与激励器大小、出口面积有关外,还与出口形状有关,采用方孔 矩形孔形式的开口有利于建立较强的合成射流;双膜与单膜工作相比,合成射流最大速度基本上是成两倍关系;金属振动膜的安装形式(受压状态)不影响合成射流随频率的变化规律,但对合成射流速度影响很大,当激励器振动膜处于螺栓拧紧受压状态时,与振动膜不受压状态相比,合成射流出口速度几乎下降了一个数量级。     

基于灰局势决策理论的维修级别分析方法

简要介绍了某型无人机维修级别分析及灰局势决策理论的一般概念,针对传统维修级别分析中经济性分析的数据来源广、模型可信度较差的情况,研究基于灰局势决策原理建模的一般方法,通过筛选原始数据并修正计算公式,大大减少了冗余计算,最后运用这一模型对某机载无线电设备进行了经济性分析。     

Blast resistance evaluation of urban utility tunnel reinforced with BFRP bars

To improve corrosion-resistance of shallow-buried concrete urban utility tunnels(UUTs),basalt fiber reinforced polymer(BFRP)bars are applied to reinforce UUTs.As the UUT must have excellent survival capability under accidental explosions,a shallow-buried BFRP bars reinforced UUT(BBRU)was designed and constructed.Repetitive blast experiments were carried out on this BBRU.Dynamic responses,damage evolutions and failure styles of the BBRU under repetitive explosions were revealed.The tunnel roof is the most vulnerable component and longitudinal cracks develop along the tunnel.When the scaled distance is larger than 1.10 m/kg1/3,no cracks are observed in the experiments.When the BBRU is severely damaged,there are five cracks forming and developing along the roof.The roof is simplified as a clamped-supported one-way slab,proved by the observation that the maximum strain of the transverse bar is much larger than that of the longitudinal bar.Dynamic responses of the roof slab are predicted by dynamic Euler beam theory,which can consistently predict the roof displacement under large-scaled-distance explosion.Compared with the UUT reinforced with steel bars,the BBRU has advantages in blast resistance with smaller deflections and more evenly-distributed cracks when the scaled distance is smaller than 1.260 m/kg1/3 and the steel bars enter plastic state.Longer elastic defamation of the BFRP bars endows the UUT more excellent blast resistance under small-scaled-distance explosions.     

Pressure relief of underground ammunition storage under missile accidental ignition

Safety of underground ammunition storage is an important issue, especially during the accidental ignition of missiles. This work investigates the pressure and temperature distribution of the multi-layer underground ammunition storage with a pressure relief duct during the accidental ignition process of the missile. A large-scale experiment was carried out using a multi-layered restricted space with a pressure relief duct to simulate the underground ammunition store and a solid rocket motor to simulate the accidental ignition of the missile. The results show that when the motor gas mass flow increased by 5.6 times, the maximum pressure of the ammunition storage increased by 5.87 times. At a certain motor flow rate, when the pressure relief exhaust area at the end of the relief duct was reduced by 1/2, the maximum pressure on the first layer did not change. But the rate of pressure relief was reduced and the time delayed for the pressure of ammunition store to drop to zero. In this experiment, when the motor ignition position was located in to the third layer ammunition chamber, the maximum pressure was reduced by 32.9％ and also reduced the rate of change of pressure. In addition, for the experimental conditions, the theoretical analysis of the pressure relief of the ammunition storage is given by a simplified model. Based on the findings, some suggestions to the safety protection design of ammunition store are proposed.     

小口径火炮侵彻钢靶模拟实验研究及有限元分析

对小口径火炮侵彻钢靶问题,分别进行了实验和有限元分析,并将所得结果进行了比较;分析了小口径火炮侵彻钢靶的侵彻过程,得到了带空腔弹丸高速垂直侵彻钢板的典型破坏模式.     

长坑道中防护门上的化爆冲击波压力研究

为了对坑道中的防护门抗化爆冲击波进行有效的设计,先需确切知道作用在防护门上的反射压力。首先基于Hopkinson比例定律,用LS-DYNA动力有限元软件模拟了常规炸药在坑道入口外爆炸情况下,长坑道中自由场冲击波峰值压力的衰减规律,并由此确定作用在防护门上的反射压力。计算结果与其他经验方法的预测结果进行了比较。可供防护门的设计及动力响应研究参考。     

非晶态Ni-P合金化学镀镀液的稳定性研究

采用PdCl2溶液的稳定性试验方法,对非晶态Ni-P合金化学镀镀液(ZFHN防腐蚀镀液)的稳定性和试验条件进行了关系曲线测试及分析.规定和提出了其试验条件和最佳控制参数;试验镀液中PdCl2的最佳浓度是2.4 mg/L、可靠的pH值范围为4.0～5.0.温度、搅拌、PdCl2用量、镀液pH值是决定镀液稳定时间的重要试验条件和试验偏差大的主要因素.研究镀液的稳定性高、组分协同稳定性好,稳定试验时间大于3 min.     

任职教育青年教员应多途径提高自身素质能力

任职教育是我军院校教育改革的重要举措。青年教员作为任职教育的生力军,却存在着诸多先天性不足,制约了教学质量和教学效果。通过分析当前任职教育青年教员普遍存在的问题,并结合我校实际情况,对其如何多途径提高自身素质能力进行了探讨。     

新疆学前教育职前与职后教师的课程观现状调查

课程观是人们对课程的看法和认识,包括对课程的内容、目的、价值等问题的看法。研究运用问卷调查法对新疆193名幼儿园教师和138名学前教育专业本科学生进行幼儿教育课程观调查,研究发现:学前教育专业学生和幼儿园教师在观念上都倾向于教育训练理论;幼儿园教师的课程观倾向在职称上无显著差异;在地域上存在差异,即城市和乡镇幼儿园教师的课程观均倾向于教育训练理论,而连队(村)幼儿园教师无明显的课程观倾向。     

中国传统文化精神在抗战文学中的表现

抗日战争决定了抗战文学必然和中国传统文化保持着血肉联系,这使得抗战文学表现出向传统文化回归的价值趋向。传统文化观念中的正气、骨气、义气,以及缘、忍、孝等许多东西在抗战文学中得到了生动地表现。因此,极大地丰富了抗战文学的内容。