Analysis of Corrosion Mechanisms of Low-cement or No-cement Al_(2)O_(3)-MgO Gunning Mix with Special Calcined Alumina in Rotary Slag Test

Al_(2)O_(3)-MgO and Al_(2)O_(3)-spinel low cement castables(LCC-AM and LCC-AS)have been extensively used in steel ladles as working linings.Nevertheless,the use of alumina-magnesia gunning mixes has been mainly kept for maintaining these castable linings,because of high rebound loss,poor green strength,high porosity and short life-span.Thanks to a high BET alumina(MC-G),it is now possible to develop a series of high-performance no-cement or low-cement Al_(2)O_(3)-MgO gunning mixes(NCG-AM or LCG-AM).The paper focuses on the BOF slag resistance of NCG-AM,LCG-AM,LCC-AM and LCC-AS.The corrosion mechanisms of rotary slag samples were studied by scanning electron microscopy(SEM/EDS).The results reveal different microstructures around MgO particles,depending on the four used compositions.Continuous and thicker spinel phases were formed in NCG-AM,which was proved to have the best corrosion resistance after the dynamic slag test.MC-G can provide a high diffusion flux of Al^(3+)in terms of kinetics and hence inhibits Kirkendall porosity around MgO particles.In addition,a continuous spinel phase acts like a pinning nail to reinforce the matrix and thus decreases erosion by slag.In contrast to NCG-AM,the porous spinel phase was found around unreacted MgO particles and some particles were carried away near the interface of LCC-AM and slag.The NCG-AM containing MC-G had been tested in two steel plants,and it extended the service life of the ladles up to 50%.In addition,this study suggests the potential application of NCG-AM as steel ladle linings.

Numerical Simulation and Measurement of Dynamics of Testing Gun Mount

In order to decrease the impact on shooting accuracy caused by human factors in the machine gun type approval testing,a new type testing gun mount system was developed to replace gunner to conduct the automatic shooting.The finite element model was first established and then the natural characteristics of the system were obtained by calculation.On basis of calculation results,the modal testing system was set up and the experimental points,including the exciting points and the measure points were determined.Finally,modal experiment of the system was carried out and the experimental modal parameters were obtained.The simulation and experiment results indicate that the dynamic characteristics of the system have a rational matching with the shooting frequency and the finite element model were well demonstrated.The study provides a new way for shooting accuracy test in type approval testing of firearms and possesses reference value for dynamic modification and optimization design.

Comparative analysis of the effects of gunpowder and plasma ignition in closed vessel tests

This paper presents the results of a comparative investigation into the effects of the ignition method on the ballistic properties of a single-base gun propellant,as determined via closed vessel tests.Conventional gunpowder ignition and plasma jet ignition methods were used,and differences in the ignition time were analysed.The influence of the ignition method on the dynamic vivacity is discussed.It is shown that this influence is significant in the first phase of the combustion process,and with respect to the low values of the loading density.In the second phase of the combustion process,and for large values of the loading density,the dynamic vivacity plots for the two ignition methods converge.Regarding the burning law,close values of the exponent were obtained for the two ignition methods.The dynamic vivacity plots determined for plasma ignition reveal stronger dependence on the loading density than those determined for gunpowder ignition.The conclusion is that plasma ignition is not a solution to the problems inherent to the process of determining the ballistic properties of propellants,which results in deviation of the burning process from the geometric burning law.

Design,fabrication,and testing of an X-band 9-MeV standing-wave electron linear accelerator

In this study,an X-band standing-wave biperiodic linear accelerator was developed for medical radiotherapy that can accel-erate electrons to 9 MeV using a 2.4-MW klystron.The structure works atπ/2 mode and adopts magnetic coupling between cavities,generating the appropriate adjacent mode separation of 10 MHz.The accelerator is less than 600-mm long and constitutes four bunching cells and 29 normal cells.Geometry optimizations,full-scale radiofrequency(RF)simulations,and beam dynamics calculations were performed.The accelerator was fabricated and examined using a low-power RF test.The cold test results showed a good agreement with the simulation and actual measurement results.In the high-power RF test,the output beam current,energy spectrum,capture ratio,and spot size at the accelerator exit were measured.With the input power of 2.4 MW,the pulse current was 100 mA,and the output spot root-mean-square radius was approximately 0.5 mm.The output kinetic energy was 9.04 MeV with the spectral FWHM of 3.5%,demonstrating the good performance of this accelerator.

Quantitative Testing of Defect for Gun Barrels

The magnetic flux leakage (MFL) method is commonly used in the nondestructive evaluation (NDE) of gun barrels. The key point of MFL testing is to estimate the crack geometry parameters based on the measured signal. The analysis of magnetic leakage fields can be obtained by solving Maxwell’s equations using finite element method (FEM). The radial component of magnetic flux density is measured in MFL testing. The peak-peak value, the separation distance between positive and negative peaks of signal and the lift-off value of Hall-sensor are used as the main features of every sample. This paper establishes the multi-regression equations related to the width (the depth) of crack and the main characteristic values. The regression model is tested by use of the magnetic leakage data. The experimental results indicate that the regression equations can accurately predict the 2-D defect geometry parameters and the MFL quantitative testing can be achieved.

基于身管应变的小口径火炮弹丸速度测试方法

针对传统火炮弹丸速度测试方法中存在难以获取整条速度曲线、易受环境影响、体积庞大、成本较高、操作复杂等问题,提出了一种基于身管应变的小口径火炮弹丸速度测试方法。基于30 mm口径火炮设计了应变测试仪,实现身管外壁应变测试。根据厚壁圆筒理论计算得出火炮膛压曲线,通过弹底压力解算模型得出弹底压力曲线,与弹载存储测试方法得到的弹底压力曲线进行对比。结合弹丸运动方程得出弹丸速度曲线,采用四阶龙格库塔算法建立弹丸速度仿真模型,将应变测试、弹载存储测试得到的弹丸速度曲线与仿真曲线进行对比。结果表明:应变测试、弹载存储测试与仿真弹丸速度曲线趋势基本吻合,最大速度误差分别为1.1%和0.5%,验证了应变测试方法的可行性,为小口径火炮弹丸测速开辟了新途径。

2/1樟单基发射药的真空与非真空环境安定性试验可替代性研究

基于深空探测用单基发射药在外太空中要经受长时间真空、温度交变等复杂的太空环境,而现有标准的安定性评估方法对其不适用的情况,设计了2/1樟单基发射药在75℃高温真空和非真空条件下的对比试验,测试双环境应力下药剂的安定剂含量、热分解性能及药剂成分等安定性敏感参量。结果表明:在试验周期10d内,药剂在75℃真空和非真空的试验环境下,其二苯胺含量、分解温度和氮含量等参数无显著性差异。本研究可为单基发射药在复杂多变环境下的安定性评估提供参考。

基于双气炮冲击试验系统的冲击响应谱试验技术

针对大尺寸结构垂向高量级冲击响应谱的试验需求,通过对比冲击响应谱试验的各类实现方式,提出基于高量级气炮冲击试验系统进行两点冲击的试验技术。验证试验表明,采用双气炮可以实现大尺寸结构垂向高频高量级冲击试验的边界均匀性,避免单点冲击响应谱试验的欠试验问题,为航天器整机研发提供更真实可靠的数据。同时,双气炮冲击试验系统在理论上具备扩展能力,可为更大尺寸产品的高量级冲击响应谱试验提供支持。

穿戴式机械臂立姿射击机枪动力响应试验研究

穿戴式机械臂是一种新型单兵装备,可以辅助士兵单手持机枪进行射击,提高单兵火力打击的能力。提出了一套穿戴式机械臂立姿射击机枪动力响应试验方案,构建了测试系统,对穿戴式机械臂立姿射击机枪动力响应进行了试验研究。利用高速摄影采集并分析了射击过程中的人体以及枪口的运动参数。结果表明,穿戴机械臂进行机枪连发射击时,机枪枪口位移响应不大且人体稳定,尤其是在上下方向上,人体各点的位移量均未超过5 mm且人体肩部承受的后坐力很小。故穿戴式机械臂起到了较好的辅助射击作用,提升了士兵立姿进行机枪射击的稳定性。

降低射孔爆轰伤害的超深探井测试管柱安全控制措施

国内超深探井试油采用射孔-测试联作工艺,超深井小井眼射孔易出现封隔器下部管柱及封隔器中心管弯曲和断裂等井下复杂情况。根据气体克拉柏龙方程和爆轰气体能量公式,导出射孔爆轰井底和封隔器处最大峰值压力计算公式;根据管柱力学屈曲理论和材料力学弯曲理论,导出射孔段管柱的弯曲应力计算公式;结合峰值压力下的活塞效应,导出射孔冲击载荷作用下管柱的应力计算公式,判断管柱的强度安全。根据射孔段管柱力学分析成果,采用改变管柱组合、调整工具下入顺序、加入双向减震器、分段延时射孔等技术,建立了超深探井测试管柱安全控制措施。以LX1井为例,实测了管柱震动加速度,上、下高速压力计实测上、下峰值分别为100、150 m/s^(2)和60、80 m/s^(2),相差40%~50%,说明双向减震器可以起到减震降损的作用。经多口超深井探井现场应用,验证了安全控制措施的可靠性。

软式内镜活检管腔干燥方法及时间研究

目的探讨软式内镜活检管腔的干燥方法和干燥时间。方法将临床诊疗使用过的胃镜随机分为5组,结肠镜随机分为6组,每组均进行60次实验。所有胃镜和结肠镜经规范清洗和消毒后,第1组活检管腔常规使用压力气枪持续吹气30 s进行干燥;剩余各组先用内镜干燥机干燥5 min,再使用压力气枪对活检管腔持续吹气30、40、50、60 s(胃镜)或30、40、50、60、70 s(结肠镜)。干燥时间结束时,使用氯化钴试纸判断内镜管腔的干燥程度。结果胃镜常规吹气30 s的干燥合格率为20.0%,结肠镜为18.3%;胃镜干燥机干燥5 min+吹气60 s,结肠镜干燥机干燥5 min+吹气70 s,干燥合格率均为100%;胃镜、结肠镜各组组内干燥合格率比较,差异有统计学意义(均P<0.05)。结论软式内镜用内镜干燥机干燥5 min的基础上,胃镜活检管腔吹气时间60 s,肠镜活检管腔吹气时间70 s,可以保证内镜活检管腔的干燥效果。

涡扇发动机吞雹试验

为研究某型涡扇发动机吞雹能力,按照CCAR-33R2标准33.78(a)条开展了整机吞雹试验方法研究及验证。梳理了试验流程,确定了试验条件,对发动机、试车台等进行了分析,开展了防护装置、摄影装置、投射装置设计,并对冰雹的制作方法进行了研究。通过投射装置实现了冰雹向发动机的投射,同时设计了试验前的校靶试验和空炮试验,通过校靶试验保证了投射的速度和准确性,通过空炮试验测试了投射装置对发动机进气的影响,又通过高速摄影验证了冰雹投射的速度和撞击位置的准确性。发动机吞入冰雹过程中推力出现短时减小,随后恢复了稳定工作,吞雹后发动机排气温度下降约2%~3%,转差变化约-0.6%~0.2%,推力下降约0.1%~1.6%;其余参数无明显变化,通过低压测点时域信号采集了风扇部分的冲击响应;试验后分解检查5片风扇叶片进气边变形,未出现掉块情况,未发现可能危及飞行安全的结构损坏,验证了某型涡扇发动机的吞雹适航符合性。

渤海C井深层超高温射孔断爆案例分析

随着渤海油田勘探向深层发展,探井测试作业中采用超高温射孔的频次逐渐增多。由于作业经验相对较少,采用超高温射孔测试联作工艺的渤海C井在作业过程中出现断爆事故。为了深入探究原因,建立了断爆原因分析决策树,从火工品质量、射孔器材、射孔枪装配质量控制以及射孔枪下入操作规范性四个方面进行了系统而详细的分析研究。最终,确定射孔枪弹架结构缺陷为主要原因,同时也不能排除射孔枪人员装配质量控制可能存在的次要因素。基于此,制定了一系列关于超高温射孔作业的质量控制措施,包括射孔枪装配、射孔枪送入操作规范以及作业管理等,对今后超高温射孔作业具有非常重要的指导意义。

Influence of Firing Temperature on Properties of Gun Propellants

Initial firing temperatures play an important role on the combustion rate of propellant. In gun propellants, initial temperature is a key factor for both accuracy and safety. Ideally, the initial temperature of the propellant should not influence the ballistic properties of the round. Nevertheless, constant initial temperature coefficients can not be achieved easily. This work focuses on the influence of the firing temperature on the ballistic properties, the mechanical integrity and the sensitivity to impact of nitrocellulose based propellants. Combustion rates have been determined by closed vessel tests. Ballistic properties have been investigated by firing 5.56 cartridges. The propellants have been conditioned at temperatures ranging from -54 ℃ to ＋71 ℃ before firing. The largest temperature coefficient is observed at high temperatures. The temperature sensitivity of the peak pressure in the combustion chamber can not be fully explained by the results from the closed vessel test. The authors speculated that the mechanical behaviour of the propellant grains at low temperatures influences also the overall ballistic properties of the round. Impact tests with propellants conditioned at low and high temperatures permit to investigate their mechanical strength under extreme temperatures and to better understand the propellant performance during firing. Tests on aged propellants have been conducted as well.

Influence of Gas Composition on the Resisting Ability of Gunning Material for Blast Furnace to Carbon Monoxide Corrosion

This paper describes the resisting ability of gunning material for blast furnace to carbon monoxide corrosion under the mixed gas condition through inletting hydrogen into pure CO . A standard for testing ike resisting ability of refractory to CO corrosion with mixed gas instead of pure CO has also been discussed. The results show : the addition of hydrogen accelerates the CO corrosion on gunning material ; the same results has been reached with the CO , 200 hours and CO 95 % + H2 5 % , 24 hours. It is reasonable to use CO 95% + H25% , 24 hours instead of pure CO, 200 hours to lest the resisting ability of refractory to carbon monoxide corrosion.

Test Apparatus for Performance Evaluation of Compressed Air End-Use Applications

Compressed air is an integral utility part of industrial utility systems. Any improvement in compressed air system will lead to reduction in utility cost. The effectiveness of utilization side of compressed air is usually dependent upon operator’s discretion. There are no performance testing methods available for testing existing end use equipments. A test apparatus for estimation of compressed air flow based on measurement of pressure reduction in a fixed volume cylinder in a given time is developed. The test apparatus is easy to build and simple to operate in an industrial environment. This can be used for measuring performance of any pneumatic end-use equipment and for benchmarking the performance. The test apparatus was used in a foundry for quantifying the performance of the old and new blow guns.

枪口焰烟光学特性测试研究

针对狙击作战中对狙击手的探测、定位及告警的需求,开展了枪口焰烟光学特性测试研究。根据枪口焰烟文献资料与光学测量设备的性能参数,设计了枪口焰烟光学特性外场测试详细方案。对某5.8 mm与7.62 mm口径弹道步枪的枪口焰烟光学特性进行了外场测试。测试结果表明,枪口焰烟辐射主要集中在2μm~5μm,持续时间约为6 ms,辐射能量最大值出现在2 ms附近,5.8 mm弹道步枪枪口焰烟在中波和长波的辐射强度均高于7.62 mm。枪口焰烟光学特性的测试结果为枪口焰烟的探测及武器发射药的改进提供了重要依据。

基于AMSAA模型的复杂舰炮武器系统可靠性增长方法

可靠性增长主要用于产品以完成初样机研制,在产品未定型之前,利用有限的时间完成故障纠正,对产品设计和制造工艺进行更改。针对复杂舰炮武器系统具有机、电、液高度耦合的工作方式,以及其系统失效时间分布复杂、难以用单一分布描述的特点,在完成系统故障模式、影响分析(FMEA)和故障树分析(FTA)的基础上,定义系统的两类故障(A类故障及B类故障),提出了基于AMSAA模型的复杂舰炮武器系统可靠性增长方法,通过趋势检验、参数估计、拟合度检验的过程,将有限的试验信息纳入AMSAA的可靠性增长和预测模型,并在系统完成定型时给出其可靠性增长水平,用于判断其可靠性指标是否满足用户提出的研制要求。

块煤智能干选技术在新疆某选煤厂的应用研究

为解决新疆某选煤厂200 mm以上块煤人工手选工艺中存在的分选效率低、劳动强度大、工人工作环境差等问题,对块煤智能干选工艺的不同智能煤矸识别方法、智能分离方式、智能算法等进行了特点对比和试验研究。采用智能干选工艺代替现有人工手选工艺。智能干选工艺突破了传统智能干选上限,使物料的识别和执行粒度上限由300 mm提高到600 mm及以上,大大提高了分选效率,降低了工人劳动强度,改善了工作环境。阐述了新疆某选煤厂采用智能干选工艺代替现有手选工艺的具体改造方案。改造后方案和原有手选系统相比,多回收块精煤3.36万吨/年,节约了人工成本,提高了选煤厂智能化水平,创造了可观的社会和经济效益。智能干选工艺的成功应用,为选煤行业超大块煤干法分选、代替手选、动筛和浅槽排矸、块煤智能干选直接出产品等工艺需求提供了参考。

基于无坐力炮复合身管上瞄准镜座的系统可靠性研究

针对无坐力炮复合身管和瞄准镜座的绑缚连接与单一金属无坐力炮身管瞄准镜座的机械连接比较而言,前者在连接瞄准镜后进行射击时,容易出现绑丝松脱、崩丝等造成瞄准镜座松动的问题,影响装备连接可靠性和射击瞄准精确度。为了验证无坐力炮复合身管上瞄准镜座在寿命周期内的可靠性问题,采用实炮射击试验,得到镜座绑缚处身管的轴向、环向最大变形率分别为0.082%、0.08%,X、Y和Z方向的振动加速度峰值分别为213 g、258g和230g,以实炮射击试验结果为依据,分析并确定冲击试验的X方向标准峰值加速度和标准脉冲宽度分别为225 g和2 ms,冲击试验结果表明:瞄准镜座的结构、强度、尺寸、与无坐力炮的绑缚连接满足可靠性要求;无坐力炮内膛尺寸偏差值在0.01~0.03 mm,其变化量值属于可控范围,对射击效果影响较小;无坐力炮配装瞄准镜后的系统零位走动量小于0.2 mil,对于400 m立靶密集度试验而言,弹丸着靶的距离偏差值约为8 cm,满足射击精度要求。该瞄准镜座可用作无坐力炮复合身管与瞄准镜的连接机构。