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Search Results: 1 - 10 of 265061 matches for " 张昌锁 "
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复线隧道爆破优化设计与实践
柳明,
金属矿山 , 2013,
Abstract: 以新风平岭2号隧道复线隧道进口开挖为研究对象,通过在隧道施工爆破过程中对邻近隧道进行现场的振动监测,应用萨道夫斯基经验公式对现场监测数据进行回归分析,控制不同目标、不同间距情况下最大起爆药量,炮眼布置方案等。既有隧道和新开发隧道间采用超前锚杆加固,增强稳定性。通过对振速波形图的分析,找到延时爆破最大振速的段位,降低该段位最大装药量以便降低最大振速,保证邻近隧道振动速度控制在安全范围内,指导后续施工。
带攻击角度约束的自适应终端滑模导引律
Adaptive terminal sliding mode guidance law with impact angle constraint

,宽桥,陈鹏
- , 2016, DOI: 10.13700/j.bh.1001-5965.2015.0502
Abstract: 摘要 针对某些导弹在对目标进行打击时需要满足零脱靶量和攻击角度约束的要求,首先基于终端滑模控制和有限时间控制理论,改进了一种快速收敛的非奇异终端滑模函数,用于设计滑模面,结合自适应指数趋近律,提出了一种自适应非奇异终端滑模控制方法,解决了传统终端滑模控制中存在的奇异问题,并使状态变量在有限时间内快速收敛到平衡点。然后将所提方法用于导引律的设计,提出了一种带攻击角度约束的自适应非奇异和有限时间收敛导引律,实现了导弹对脱靶量和攻击角度约束的要求;采用有限时间控制理论对该导引律的收敛特性进行了分析,证明了制导系统状态的全局有限时间快速收敛特性。与传统的非奇异终端滑模导引律相比,本文所提导引律能够在更短的时间内以更小的脱靶量和更高精度的攻击角度对目标实施打击。最后进行了大量的对比仿真实验,仿真结果验证了所提导引律的有效性。
Abstract:Aimed at the requirement of zero miss-distance and terminal impact angle constraint for some missiles attacking the targets, an adaptive nonsingular terminal sliding mode control algorithm based on the theories of terminal sliding mode control and finite-time control is proposed first. The algorithm avoids the singularity of terminal sliding mode control, and makes the state variables achieve the equilibrium point by improving a fast nonsingular terminal sliding mode function to construct the sliding mode surface, and employing an adaptive exponential reaching law. Then the algorithm is utilized to design the guidance law, and an adaptive nonsingular and finite-time convergent guidance law with impact angle constraint is proposed. Realizing the requirement of miss distance and attack angle of the missiles. Finite-time control theory is used to analyze the convergence of the guidance law, and proves the fast and finite-time convergence of guidance system states during the whole process. Compared with conventional nonsingular terminal sliding mode guidance law, the designed guidance law can attack the targets with less miss-distance and higher precision of expected impact angle in a shorter time. A large number of simulation experiments verify the validity of the proposed law.
河北省果园氮素投入特点及其土壤氮素负荷分析
卢树, 陈 清*, , 贾文竹
植物营养与肥料学报 , 2008, DOI: 10.11674/zwyf.2008.0507
Abstract: 以河北省果园土壤地力调查、农户调查和统计数据为基础,采用氮盈余法从果树种类和区域角度分析了果园生产体系中的氮素输入输出特点及氮养分盈余状况。结果表明,河北果园平均化肥氮投入量为438.0kg/hm2,主要品种为尿素和复合肥,有机肥氮为181.6kg/hm2,以畜禽粪为主,其中禽粪占25.5%。京津东部区和冀中、南平原区的果园氮素投入、盈余量较高;葡萄园和桃园的氮素投入水平较高;果园氮素施用与养分盈余量之间存在极显著的正相关,过量施用氮肥是氮盈余量很高的主要原因。随着氮盈余量增加,果园土壤全氮呈增加趋势,而土壤C/N均呈下降趋势,氮素盈余对土壤全氮的影响大于对土壤有机质的影响。
锚杆锚固体系中的波系特征研究
张世平,,王成,steve,zou
岩土力学 , 2007,
Abstract: 采用凝固过程中的混凝土模拟不同物理力学特性的锚固介质,用数值模拟和试验的方法研究了锚固锚杆中的波系及锚固锚杆中界面波的形成过程。数值模拟和试验模拟都表明随着锚固介质力学性质的改变锚杆中传播的波的特性发生改变。锚杆中传播的p波对锚固介质的力学特性非常敏感,随着锚固强度的增加,界面波产生,p波逐渐衰减消失。锚杆中传播的波由原来的p波占主导成为界面波占主导,波在锚固段的传播速度也由杆速度成为界面波波速。界面波的波速与锚固介质的力学性质相关,因此可以用界面波的波速来评价锚杆锚固质量以及计算锚杆锚固段长度。
注浆锚杆完整性检测方法研究
张世平,,白云龙,韩世勇
岩土力学 , 2011,
Abstract: 采用理论分析和实验室测试的方法对锚固锚杆和自由锚杆中的导波传播规律进行了研究,并在频率为20khz~3mhz范围内对锚固锚杆和自由锚杆波的传播速度进行了测试,发现锚固锚杆内不同频率的导波传播速度对锚固介质具有不同的敏感性。低频率段(20~200khz)的导波传播速度对锚杆锚固质量较为敏感,自由锚杆和锚固锚杆中导波的传播速度相差较大,适合于检测锚杆的锚固质量。高频率段(1~3mhz)的导波传播速度对锚杆锚固质量不敏感,导波的传播速度基本不变,适合于锚杆完整性检测。探索了利用高频段多频率导波检测锚固锚杆长度的方法。实验室检测结果显示,本检测方法具有很高的精度
考虑导弹自动驾驶仪动态特性的新型制导律
Novel guidance law accounting for dynamics of missile autopilot

,,宽桥,永伟,陈鹏
- , 2017, DOI: 10.13700/j.bh.1001-5965.2016.0630
Abstract: 摘要 针对拦截空中飞行目标需要满足零脱靶量和攻击角约束提高导弹制导性能等问题,首先,利用考虑噪声干扰的扩张状态观测器对目标加速度进行估计,其次,改进一种非奇异终端滑模面,将自动驾驶仪视为理想环节,然后,基于终端滑模控制理论和有限时间收敛理论推导一种滑模制导律,最后,考虑自动驾驶仪二阶动态特性,将得到的滑模制导律结合动态面控制法提出一种新型制导律。分别以不同的攻击角对机动飞行和匀速飞行的目标进行拦截,大量仿真表明,所提制导律具有良好的制导性能,能够保证导弹在零脱靶量击中目标的同时达到期望攻击角。
Abstract:Interception of air targets requires zero miss-distance and impact angle constraint to improve the missile guidance performance. First, the acceleration of the target was estimated by extended disturbance observer which also considered the noise interference. Second, a nonsingular terminal sliding mode surface was improved, which considered autopilot ideally. Third, a sliding-mode guidance law was designed based on the terminal sliding mode control theory and the theory of finite time convergence. Finally, considering the second-order dynamic characteristics of autopilot, the novel guidance law was developed combining both sliding-mode guidance law and dynamic surface control method. In simulation experiments, both maneuvering targets and constant velocity targets were intercepted with different impact angle. A large number of simulation results demonstrate that the proposed guidance law canguarantee that the missile hits the target and at the same time achieves a desired angle of impact, which performs well.
STUDY ON SEVERAL KEY ISSUES IN NONDESTRUCTIVE DETECTION OF BOLT BONDING INTEGRITY
锚杆锚固质量无损检测几个关键问题的研究

LI Yi,ZHANG Changsuo,WANG Cheng,
李 义
,,王 成

岩石力学与工程学报 , 2008,
Abstract: The latest researches on nondestructive detection of rock bolt bonding integrity are summarized.By means of theoretical analysis and laboratory research,several key issues in nondestructive detection,i.e.end reflection,consolidation wave and dynamic response of rock bolt under loading,are discussed.With the variation of free part length of different grouted rock bolts,the fact is found that the end reflection is not very obvious when the grouted length is shorter than 3/4 wave length of input signal.If changing the grout concrete strength,the relationship between consolidation wave speed and bolt bonding integrity is achieved.In addition,the testing rock bolt response under loading and the relationship between basic frequency of dynamic response and loading level are also gained.All of these relationships are valuable in engineering practice.
高频超声导波检测锚杆有效锚固长度分析
潘立业,,马洁腾,王银涛,柳明
煤炭科学技术 , 2014,
Abstract: 为检测锚杆实际有效锚固长度,得到锚固锚杆和自由锚杆中的高频超声导波传播规律,在1~15MHz频率范围内对不同锚固锚杆试件进行频率扫描,并根据试验结果得到了群速度和频率之间的关系曲线。结果表明,激发频率为2.007~2.312和3.266~3.491MHz时,导波在不同锚固质量的锚杆中传播速度几乎一致,且锚杆锚固质量对高频超声导波的传播速度影响很小,并据此得出在这个频率范围内可检测超声导波在自由锚杆中的传播速度,进而计算出锚杆的锚固长度。
高温高压下花岗岩中钻孔变形规律实验研究
郤保平,赵阳升,,康志勤
岩石工程学报 , 2010,
Abstract: 首次运用光学原理钻孔变形观测仪对600℃以内,6000m埋深静水应力以内花岗岩中钻孔变形规律及其稳定性条件进行了深入细致的实验研究。研究发现:①高温高压下花岗岩中钻孔变形根据温度和埋深应力不同,可分为黏弹性变形、黏弹–塑性变形及破坏3个阶段;②恒温恒压下花岗岩中钻孔变形具有明显的时效特性,随着时间的延长,钻孔孔壁位移逐渐增大,孔径缩小,钻孔蠕变变形量达到一定量后趋于稳定,钻孔并不发生破坏;③温度和加载应力对钻孔变形具有很大影响,保持岩体加载应力不变,逐渐升高温度,钻孔变形逐渐增大,直径缩小,温度保持不变,加载应力越大,钻孔孔壁变形量越大,钻孔内径就越小。
20~1000kHz超声导波用于锚杆锚固质量检测的探索
廖霖, , 柳明, 张胜利, 王银涛
金属矿山 , 2013,
Abstract: 为使超声波无损检测技术应用于锚杆锚固质量的检测,采用理论分析和实验室测试的方法对超声导波在锚杆中的传播规律进行了研究。在20~1000kHz导波频率范围内,对不同锚固质量的锚固锚杆进行了扫频,并根据实验结果得出了群速度随频率变化曲线。研究结果表明:频率较低时,同一频率导波在不同锚固质量的锚杆传播的群速度不一样,可用于锚杆锚固质量的检测;频率较高时,它们的群速度几乎一致,可用来检测锚固锚杆的长度,但存在一些可用于锚杆锚固质量检测的导波。
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