作者希望通过管理科学学术联盟 NNSA (DE-NA0001989 和 DE-NA0002919) 在进行这项研究时承认美国能源部的财政支持。最后, 作者要感谢洛斯阿拉莫斯国家实验室的合作, 以支持目前和今后的调查工作。

1. 样品和靶材准备
注: 在下面的协议中, 我们将详细说明准备样品和目标材料所需的步骤, 稍后将在反向几何法板撞击实验中使用。在这个设置, 一个传单板 (也样品), 在一个穿甲弹的前面举行, 将通过一个单一的阶段气体枪发射, 并作出冲击的固定目标板放置在气体枪的目标室。下面的协议中描述了一个典型的传单和目标板组件, 如图 1所示。
<ol><li>a 节99.999% 商业纯度多晶铝棒成圆盘后, 将用作传单板 (样品)。 注: 这可以通过使用低速锯, 以防止高温和残余应力在工件。</li>
	<li>将车床上的样品盘转到直径76毫米, 厚度为5.6 毫米。</li>
	<li>在样品盘上钻三均布孔5毫米直径为62毫米直径的粗圆形, 稍后将用于将样品固定在穿甲弹上。</li>
	<li>研磨两侧的样品板, 以达到平整度和平行公差的近10µm 直径的样品。<ol>
<li>使用具有相对粗粒度 (10-20 µm) 的商用研磨机在样品板表面上进行粗圈。 注意: 可以在这个步骤中添加一个重量, 直到重叠曲面达到均匀的灰色, 表示磁盘直径的均匀性。</li>
		<li>用乙醇清洗研磨样品, 去除残余颗粒, 矿物油。然后, 用1µm 金刚石膏在抛光布上抛光样品板的两面。</li>
		<li>在绿色单色光源16下, 通过与感兴趣表面接触的光学平面观察光带, 检查样品的平整度。 注意: 平整度可以通过观察样品表面的光带的曲率来量化, 或者通过计算直径的带数, 如图 2所示。<ol>
<li>移动到下一步, 如果在样本直径上看到3个光带或更少, 表明平坦度约为2µm. 否则, 重复步骤 1.4.1-1.4.3, 直到3光带或更好的实现。</li>
		</ol>
</li>
	</ol>
</li>
	<li>重复步骤 1.1-1.3, 以制造目标板块。a 节将沉淀硬化 (高强度) 合金棒 (材料表) 放入圆盘中, 然后将其加工成直径为25毫米, 厚度为7毫米。最后, 研磨两边平到大约10µm。<ol>
<li>将目标板上的两个表面都用15µm 氧化铝粉在矿物油上, 直到表面达到甚至暗淡的灰色外观。 注: 金刚石浆料的等效粒径可用于获得更快的去除率和更好的表面沉思。此外, 还可以使用权重。</li>
		<li>重复步骤1.4.2。</li>
		<li>通过重复步骤1.4.3 检查目标板的平整度。如果观察到1波段或更好, 则继续下一步。否则, 重复步骤 1.4.1 1.4.3 直到1光波段或更好的实现。如果需要全息光栅, 请继续步骤 1.5.4, 否则跳到步骤1.6。</li>
	</ol>
</li>
	<li>利用步骤 1.1-1.3 中描述的类似过程来制造铝环。<ol>
<li>一节铝管的内外直径为41毫米和32毫米, 分别成环, 然后面对两侧厚度为7毫米。</li>
		<li>钻六3毫米直径槽均布在34.5 毫米直径螺栓圈子。这些将在稍后的房子六电压偏置铜引脚, 这将使倾斜测量将在冲击。</li>
		<li>使用步骤1.4 中详细的步骤, 研磨、圈、清洁和抛光铝环的两面。</li>
	</ol>
</li>
	<li>在平坦的固定钻机上使用两部分环氧树脂混合物将平板目标板粘在铝环上, 如图 3所示。允许环氧树脂在室温下过夜。 注: 这两部分是固定在一个平坦的钢阶段使用三螺丝, 这是轻轻地手收紧, 使施加的压力, 目标和环防止环氧树脂泄漏向外。<ol>
<li>使用丙酮从径向槽或板材表面除去任何遗留的粘合剂。</li>
		<li>将目标板/铝环组件插入 POM 环中。 注: POM 磁盘稍后将安装到一个具有旋转自由度的目标持有者, 这将使测试材料在枪管内的对准。</li>
		<li>将六径向插槽的位置标记为 POM 环的内部步骤, 并在标记的位置钻取六个穿过厚度的孔。</li>
		<li>第6节从 15 AWG 漆包线的线轴上的铜销, 长度为50毫米, 并从其中两个中取下漆包线层。按对称模式将针脚按在插槽中: 两个接地销放置在圆的相对位置。将引脚通过插槽, 并留下大约2毫米凸出向外从环的表面。 注: 引脚用于测量倾斜角度并提供触发信号。</li>
		<li>将铜销的弯曲端固定在 POM 环的后表面, 使用超快的环氧树脂。</li>
		<li>使用低粘度的两个部分环氧树脂混合物密封的缝隙之间的铝环和内壁的 POM 环。允许环氧树脂在室温下过夜。</li>
	</ol>
</li>
	<li>卸下从铝环表面凸出的多余的2毫米铜销。第一节用旋转工具将多余的针脚, 然后用湿300砂砂纸将剩余的沙子放到表面, 直到针脚几乎冲向铝环的表面。<ol>
<li>通过重复步骤 1.4. 1-1. 4.3, 对整个程序集进行清理和抛光。确保整个研磨组件在 2-3 光带内平整。</li>
		<li>在 pom 环的后表面焊接六铜销的两端, 并将 pom 环安装到目标持有者身上, 使用四6.35 毫米直径 pom 针脚。</li>
	</ol>
</li>
</ol>2. 自定义耐热穿甲弹的组装
<ol><li>收集耐热穿甲弹的组件组件, 如图 4所示。</li>
	<li>在铝盖的底部附加一个吊环, 并在瓶盖的凹槽上固定密封 O 形环和聚四氟乙烯键。 注: 钥匙和 O 形环是用来防止在飞行过程中, 在枪筒中的穿甲弹的倾斜和旋转。<ol>
<li>将热偶导线通过盖子底部的孔, 并将热偶导线固定在连接器上。</li>
	</ol>
</li>
	<li>将瓶盖粘附到后端, 并将全烧成硅酸铝熔岩管的前端的铝管用两部分快速设置环氧树脂。</li>
	<li>在76.2 毫米直径 H13 工具-钢合金试样持有者的孔中拉热耦合探头。</li>
	<li>采用高温水泥或等效高温胶粘剂, 将 H13 试样夹持到熔岩管的前端。</li>
	<li>将高温水泥涂在25毫米直径和3毫米厚的熔岩盘上, 坐在 H13 支架的内穿透厚度 19 mm 直径同心孔的顶部。允许高温水泥在室温下过夜。</li>
	<li>使用三氧化铝螺钉将样品固定在 H13 样品架上, 并确保样品的平整度不会因使用1.4.3 中描述的协议而改变。</li>
</ol>3. 气体枪内测试材料的装配
<ol><li>用异丙醇清洗样品的前表面和靶面, 然后使用胶带将第一面镜子固定在每个表面。</li>
	<li>螺钉拧紧一个3轴运动舞台上的一个挤压杆上方的枪管内的撞击室, 并附上棱镜持有人携带一个精密的光学棱镜到舞台上。</li>
	<li>拉一根绳子穿过枪管, 并通过铝帽上的吊环把绳子连接到穿甲弹上。</li>
	<li>将穿甲弹放入枪管中, 样品朝向撞击室, 并将目标保持器组件置于所面向样品的靶腔内。</li>
	<li>通过调整四 POM 定位销对齐目标位置, 直到目标上的第一面镜像与示例上的第一面镜像对齐。<ol>
<li>使用扩散灯泡和反射镜对样品和目标板之间的平行度进行粗对齐。调整舞台, 直到一个单一的连续反射图像的灯泡可以看到从所有的表面上对齐棱镜。</li>
	</ol>
</li>
	<li>使用自动准直器24实现精细对准。<ol>
<li>调整舞台, 直到从棱镜的后表面反射的图像与样品上的第一面镜反射的图像对齐。</li>
		<li>通过在目标保持架上转动定位螺钉来调整目标组件, 直到从棱镜的后表面反射的十字图像与目标上的第一面镜面反射的图像对齐。</li>
	</ol>
</li>
	<li>从示例和目标中移除第一面镜像。还可以从撞击室中取下反射镜、棱镜、棱镜架和调整阶段。</li>
	<li>用绳子把穿甲弹拉到气枪的臀端, 然后从帽上取下绳子。</li>
	<li>在穿甲弹和加热器头之间保持2.5 毫米的距离, 相应地调整螺钉的长度, 防止穿甲弹的背部运动朝向臀位。</li>
	<li>将热偶连接到温度诊断监视器。 注: 温度监控端上的热偶导线通过真空管在馈内。</li>
</ol>4. 激光诊断的排列和对准
<ol><li>将两个螺纹锚放在调焦探头支架背面的孔中。拧紧两个螺钉通过锚, 直到他们到达 POM, 使自由改变入射光束的角度。<ol>
<li>在调焦探头架的底部钻一个穿过厚度的孔, 并将其固定在螺纹圆柱磁铁上。</li>
		<li>将光纤调焦探头通过铝管, 并将探头粘附到铝管上, 在探头头和铝管尖端周围应用超快环氧。尽量将探头头向前推入管内, 但一定要使探头透镜远离环氧树脂。等待, 直到额外的快速设置环氧树脂硬化。</li>
		<li>将光学调焦连接到全光纤 NDI/TDI 干涉仪31, 并将调焦组件放在目标支架上, 瞄准目标的后表面。</li>
	</ol>
</li>
	<li>打开激光, 在这种情况下, 2W 铒光纤耦合激光器, 0.2-0.4 W 功率。接下来, 使用调焦组件上的螺钉调整调焦探头的位置, 直到达到适当的光耦合, 并优化获得的信号。</li>
	<li>调整可变比耦合器, 以匹配参考和多普勒移动光的强度, 直到在示波器显示的信号优化。 注: 如果需要横向运动诊断, 请参阅步骤 4.5-4.6。</li>
	<li>将两个螺纹锚放在 POM 调焦支架背面的孔中, 然后拧紧两个螺钉, 直到它们接触 pom。<ol>
<li>在调焦探头架的底部钻一个穿过厚度的孔, 并将其固定在螺纹圆柱磁铁上。</li>
		<li>将光纤准直探头通过铝管拉出, 并将探头和铝管的尖端环氧贴在铝管上。尽量将探头头向前推入管内, 但一定要使探头透镜远离环氧树脂。等待, 直到额外的快速设置环氧树脂硬化。</li>
		<li>在4.4 重复上述步骤, 使两个组件, 并把它们放在撞击室。</li>
	</ol>
</li>
	<li>调整接收光纤准直器的位置和角度, 用磁铁和两个螺钉对 POM 持有人, 直到功率监视器测量的一阶衍射光束的强度得到优化。</li>
	<li>断开电源显示器并将两个接收准直器连接到全光纤 TDI 干涉仪31。</li>
</ol>5. 高温反几何法/压力-剪切板冲击试验的执行
<ol><li>通过拧紧撞击室入口处的四个夹具来保证主法兰的安全, 然后使用螺栓固定在辅助法兰上的聚酯薄膜关闭腔室。</li>
	<li>将密封压力提高到207帕, 然后通过拧紧法兰中的螺钉关闭在臀端的气枪。</li>
	<li>打开臀端真空泵, 然后打开目标室端真空泵。</li>
	<li>确保不存在的穿甲弹的运动, 由前部和背部之间的压力差, 由穿甲弹。等待, 直到房间被疏散到压力小于 100 mTorr。</li>
	<li>打开基于激光振幅的穿甲弹冲击速度测量系统。</li>
	<li>将加热器移至标记位置, 然后打开加热器。将加热器的温度提高100摄氏度, 直到达到所需的样品温度。</li>
	<li>将点火转储室加压至1103帕, 并根据所选的撞击速度将所需的荷载室达到所期望的水平。另外, 把穿甲弹捕手固定在撞击室里。</li>
	<li>关闭加热器, 并立即将加热器向上移动到加热器-好的。记录在样品表面用穿甲弹热电偶测量的温度诊断显示器上显示的温度。</li>
	<li>一旦密封压力降到零, 立即打开密封阀, 释放点火转储室。</li>
</ol>

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S., Ahrens, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Compressional+sound+velocity,+equation+of+state,+and+constitutive+response+of+shock-compressed+magnesium+oxide.">Compressional sound velocity, equation of state, and constitutive response of shock-compressed magnesium oxide.</a> Journal of Geophysical Research: Solid Earth. 100, 529-542 (1995).</li><li>Tan, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hugoniot+and+sound+velocity+measurements+of+bismuth+in+the+range+of+11-70+GPa.">Hugoniot and sound velocity measurements of bismuth in the range of 11-70 GPa.</a> Journal of Applied Physics. 113, 093509 (2013).</li></ol>

作者没有什么可透露的。

上述方法和协议详细说明了在高温下正确执行反向几何正常板撞击实验的程序。在这种方法中, 我们对火炮枪管进行自定义修改, 在现有气体枪的高压 (臀) 端的情况下, 西预备队大学, 以房子的电阻式加热器线圈轴向和旋转自由度。电阻式加热器线圈系统, 使薄铝试样, 持有在加热器的前端, 耐高温弹, 加热到接近熔化温度 (超过640°c), 在射击之前。利用加热器壳体适应与耐热弹托结合, 进行了高温板撞击实验, 不需要特殊的实验考虑, 这在使用常规方法时是典型的, 如, 需要进行远程倾斜调整, 实时反馈, 以保持目标和传单板在加热过程中的平行度。总的来说, 与传统方法相比, 新方法大大减少了协议部分的步骤数目。
在实验性的协议部分, 我们详细的步骤: 1) 样品和目标材料的准备工作, 其中的传单和目标板是仔细加工, 研磨和抛光, 在平行和平整度公差所需的产生与撞击面足够平行的前平面波;2) 组装自定义耐热的木弹, 能够确保加热的样品板, 同时减轻热流到穿甲弹的身体, 和枪管。另外, 穿甲弹房子钥匙, 队友到现有的钥匙方式在枪桶防止整个穿甲弹装配的自转在它的旅行下在枪桶的长度期间。最后, 在步骤3-5 中, 我们详细介绍了在进行实验之前对样品和目标板进行对准的协议, 加热了飞行板 (样本) 和实验的执行。在后面的部分中, 我们演示了如何从图 1中提供的原始数据中验证协议的准确性。最后, 我们提出了成功的高温正常板撞击实验的结果, 使测量的应力/粒子速度状态在样品/目标界面, 以及, 温度相关的纵向声学样品材料的阻抗。
在不久的将来, 随着对穿甲弹设计的适当调整, 这种方法有望实现更高的温度板撞击实验, 这将使其能够在近距离探测高熔点材料的动态材料行为方面发挥作用。熔化温度。考虑到这种方法的通用性, 将使用几种不同的实验配置来研究跨板的动态材料行为。例如, 高温逆向几何板块撞击实验可以适当地设计来测量金属在升温时的冲击波速度, 而压力-剪切板撞击实验可以进行评估大应变和超高剪切速率下的动态不适应性。

在工程应用中, 材料受多种条件的限制, 其性质可以是静态的或动态的, 再加上高度的变形和温度, 从房间到靠近熔点的位置不等。在这些热力学极端之下材料行为可能剧烈地变化;因此, 近一个世纪以来, 在受控加载机制1、2、3的情况下, 开发了几个实验, 旨在探讨材料行为的动力响应和/或其他特性。,4,5,6,7,8,9,10,11,12,13,14. 对于负载在低到中间应变率 (10-6-100 /秒) 的金属, 采用伺服液压或精密螺杆万能试验机研究了各种加载方式下的材料反应, 并变形水平。但是, 随着应用应变率的增加超过了中间应变率 (i., > 102/秒), 其他实验技术就成为必要的, 以探测机械反应。例如, 在 103/秒的装货率高达 5 x 104/秒的全尺寸或小型化的拆分-霍普金森压力杆, 使此类测量可以做8,15。
传统上, 轻型气体枪和/或爆炸驱动的板块撞击实验已经被用来研究动态不适应性和其他现象, 如散裂, 或相变发生的非常高的应变率 (105-107/秒)16,17,18,19,20,21,22, 或组合的高压和动态负载。通常情况下, 板块撞击实验涉及发射一个飞行板, 最初在气枪的臀端, 然后沿着枪管的长度向下移动, 并与精心对准的固定靶板碰撞撞击室。由于撞击, 在飞行物/目标界面上产生了正常和/或联合的压力和剪切应力, 它通过板块的空间尺寸作为纵向和/或组合纵向和横向应力波。这些波在靶板后表面的到达会影响目标板的瞬时自由表面粒子速度, 这通常通过干涉技术进行监测。为了允许对测量的粒子速度和时间历史的解释, 有必要在撞击14,23产生与撞击表面平行的平面波。为确保前者, 撞击必须发生在小于一毫弧度12、24的顺序上, 其平面度的撞击面比两个千分尺5、25更佳。
板块撞击实验已经适应了包括加热元素, 使调查的材料行为延伸到热力学极端26,27,28,29。这些适应通常包括增加一个感应线圈, 或一个电阻加热器元件的目标端的气枪;虽然这些适应已经证明在实验上是可行的, 但这种方法内在地导致了特殊的实验挑战, 需要仔细考虑。其中一些实验性的并发症包括在加热目标 (样品) 板时, 目标保持器组件和/或校准夹具的不同成分的热膨胀, 这需要实时校准调整,通常采用带有连续反馈的遥控对准工具, 以保持样品和目标板之间的关键并行公差。在压力-剪切板冲击试验方案中, 加热试样需要用耐高温金属光栅代替传统的高分子光栅, 以监测在自由表面的横向粒子速度。靶板。此外, 加热的样品可以增加限制的冲击速度, 可以在某些实验方案, 如在高应变率联合压力和剪切板冲击配置, 在那里可能需要特殊的考虑为了防止对实验结果的明确解释, 利用可能是温度依赖性的前后靶板的声学阻抗计算。最后, 对于需要具有光学窗口的目标板的其他实验方案, 试样、粘结层和/或涂层之间的公差在高温下变得越来越难维持19。
为纾缓上述实验挑战, 我们已对位于西储大学 (CWRU)7、30、31、32 的现有单级气枪进行自订改装..这些修改使在耐热弹托的前端举行的薄金属试样被加热到超过1000年°c 的温度, 在射击之前, 这允许高温正常和/或联合压力-剪切板冲击实验是进行。与用于高温板撞击研究的大多数常规方法相比, 这种方法已被证明可以缓解上述几个实验难题。例如, 这种方法已经被利用来实现小于一毫弧度的倾斜角, 而不需要进行远倾角调整30, 或者在实验期间监测倾斜变化的额外光学元件。其次, 由于目标板在环境温度下保持不变, 这种方法不需要特殊的耐高温全息光栅来测量斜撞击实验中的横向粒子速度;此外, 可以利用更高的冲击速度, 而不会产生目标板的风险, 从而降低实验结果解释的复杂性。添加时, 这种方法可用于执行高温逆向几何正常板撞击实验, 为选择样品材料提供了我们的关系。这些可以通过阻抗匹配技术获得, 或者另外, 从样品的后表面对稀疏风扇进行分析, 在卸载33、34 期间对试样冲击速度的变化进行相关信息..在高温联合压力-剪切板冲击构型中, 这种方法使薄膜的动态不适应性能够被广泛的温度和塑性变形范围所研究, 应变率可达 107/秒, 取决于薄试样的厚度16,27,29。
我们将介绍执行上述典型的高温板撞击实验所需的协议。接下来将有一节专门介绍使用现有技术获得的代表性结果。最后, 对结果的讨论将在结论之前提出。

<table>
	<tbody>
		<tr>
			<td>99.999% commercial purity polycrystalline aluminum</td>
			<td>Goodfellow</td>
			<td>AL007970</td>
			<td>Material for flyer plate (sample)</td>
		</tr>
		<tr>
			<td>H13 tool steel</td>
			<td>Fabrication Center of CWRU</td>
			<td>N/A</td>
			<td>Material for the sample holder</td>
		</tr>
		<tr>
			<td>Solution treat &#38; age Inconel 718 alloy</td>
			<td>High Temp Metals</td>
			<td>N/A</td>
			<td>(1.005/1.015)&#34; Dia x 24&#34;, Material for target plate</td>
		</tr>
		<tr>
			<td>Photoresist S1805</td>
			<td>MicroChem</td>
			<td>N/A</td>
			<td>Material of the photoresist for holographic grating</td>
		</tr>
		<tr>
			<td>Developer CD-26</td>
			<td>MicroChem</td>
			<td>N/A</td>
			<td>Developer to the photoresist for holographic grating</td>
		</tr>
		<tr>
			<td>Aluminum 6063 tube</td>
			<td>McMaster-Carr</td>
			<td>4568T19</td>
			<td>Material for the ring in target assembly</td>
		</tr>
		<tr>
			<td>Black Delrin (R) Acetal Resin Rod (4-1/2&#34; Dia.)</td>
			<td>McMaster-Carr</td>
			<td>8576K81</td>
			<td>Material for the Delrin holder in target assembly</td>
		</tr>
		<tr>
			<td>White Delrin (R) Acetal Resin Rod (1/4&#34; Dia.)</td>
			<td>McMaster-Carr</td>
			<td>8572K51</td>
			<td>Material for the Delrin pins in target assembly</td>
		</tr>
		<tr>
			<td>Aluminum 6061 tube</td>
			<td>McMaster-Carr</td>
			<td>9056K24</td>
			<td>Material for the body in projectile assembly</td>
		</tr>
		<tr>
			<td>Aluminum 6061 rod</td>
			<td>McMaster-Carr</td>
			<td>8974K88</td>
			<td>Material for the cap in projectile assembly</td>
		</tr>
		<tr>
			<td>Teflon sheet</td>
			<td>McMaster-Carr</td>
			<td>8711K98</td>
			<td>Material for the key</td>
		</tr>
		<tr>
			<td>LAVA-FF - Alumina Silicate disc</td>
			<td>Technical Products</td>
			<td>CWR-033116-1</td>
			<td></td>
		</tr>
		<tr>
			<td>LAVA-FF - Alumina Silicate tube</td>
			<td>Technical Products</td>
			<td>ALR11515</td>
			<td></td>
		</tr>
		<tr>
			<td>Alumina Pan Slotted Head Bolt</td>
			<td>Ceramco</td>
			<td>A83200PANSLT0.500</td>
			<td></td>
		</tr>
		<tr>
			<td>409 N70 Buna-N O-ring</td>
			<td>The O-ring Store</td>
			<td>B70409</td>
			<td></td>
		</tr>
		<tr>
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conducting elevated temperature normal and combined pressure-shear plate impact experiments via a breech-end sabot heater system

提出了一种在1000摄氏度的试验温度下进行常规和/或联合压力-剪切板冲击实验的新方法。该方法使高温板撞击实验旨在探索材料在热力学极值下的动态行为, 同时减轻在进行类似实验时面临的几个特殊实验挑战。采用传统的板材冲击法。在西储大学的情况下, 对单级气枪的臀端进行自适应改装;这些改装包括由 SAE 4340 钢制成的精密加工延伸件, 它的战略设计是配合现有的枪管, 同时提供高公差匹配孔和键槽。延伸件包含一个垂直圆筒加热器-好, 安置加热器汇编。电阻线圈加热器头, 能够达到1200摄氏度的温度, 连接到一个垂直的阀杆, 具有轴向/旋转自由度;这使得在耐热的穿甲弹的前端举行的薄金属试样被均匀地加热到所需的试验温度。通过加热飞行板 (在这种情况下, 样品) 在枪筒的臀端, 而不是在目标端, 可以避免几个关键的实验挑战。这些指标包括: 1) 由于目标支架组件的几个成分的热膨胀, 在加热过程中靶板的对准发生了严重的变化;2) 由于诊断元素 (i.、聚合物全息光栅和光学探针) 太靠近加热目标组件而产生的挑战;3) 在具有光学窗口的目标板上出现的挑战, 在高温下, 试样、粘结层和窗口之间的关键公差变得越来越难以维持;4) 在组合压剪板撞击实验中, 需要用耐高温衍射光栅测量目标自由表面的横向粒子速度;5) 由于热软化和可能产生的边界目标板, 对测量的自由表面速度与时间剖面的明确解释所需的冲击速度施加限制。通过利用上述的适应性, 我们提出了一系列的反几何法平板撞击实验的结果, 对商业纯铝在一系列的样品温度。这些实验表明, 在受冲击状态下, 颗粒速度减小, 这表明材料软化 (后屈服流应力降低) 随试样温度的增加。

Watch this Scientific Journal Video about Conducting Elevated Temperature Normal and Combined Pressure-Shear Plate Impact Experiments Via a Breech-end Sabot Heater System at JoVE.com

Conducting Elevated Temperature Normal and Combined Pressure-Shear Plate Impact Experiments Via a Breech-end Sabot Heater System

在这里, 我们提出了一个新的方法来进行高温反向正常板冲击, 并结合压力和剪切板冲击的详细协议。该方法包括使用臀端电阻线圈加热器, 以加热在耐热的穿甲弹的前端举行的样品, 以达到预期的温度。

采用臀端穿甲弹加热系统进行高温常压联合压力-剪切板冲击试验

A novel approach for conducting normal and/or combined pressure-shear plate impact experiments at test temperatures up to 1000 &#176;C is presented. The ...

conducting-elevated-temperature-normal-combined-pressure-shear-plate

Nanyang Technological University

Research

JoVE Journal

Engineering

8.5K 次观看.  Case Western Reserve University. 在这里, 我们提出了一个新的方法来进行高温反向正常板冲击, 并结合压力和剪切板冲击的详细协议。该方法包括使用臀端电阻线圈加热器, 以加热在耐热的穿甲弹的前端举行的样品, 以达到预期的温度。

视频: Conducting Elevated Temperature Normal and Combined Pressure-Shear Plate Impact Experiments Via a Breech-end Sabot Heater System

Terahertz Microfluidic Sensing Using a Parallel-plate Waveguide Sensor

Refractive index (RI) sensing is a powerful noninvasive and label-free sensing technique for the identification, detection and monitoring of microfluidic samples with a wide range of possible sensor designs such as interferometers and resonators 1,2. Most of the existing RI sensing applications focus on biological materials in aqueous solutions in visible and IR frequencies, such as DNA hybridization and genome sequencing. At terahertz frequencies, applications include quality control, monitoring of industrial processes and sensing and detection applications involving nonpolar materials.
Several potential designs for refractive index sensors in the terahertz regime exist, including photonic crystal waveguides 3, asymmetric split-ring resonators 4, and photonic band gap structures integrated into parallel-plate waveguides 5. Many of these designs are based on optical resonators such as rings or cavities. The resonant frequencies of these structures are dependent on the refractive index of the material in or around the resonator. By monitoring the shifts in resonant frequency the refractive index of a sample can be accurately measured and this in turn can be used to identify a material, monitor contamination or dilution, etc.
The sensor design we use here is based on a simple parallel-plate waveguide 6,7. A rectangular groove machined into one face acts as a resonant cavity (Figures 1 and 2). When terahertz radiation is coupled into the waveguide and propagates in the lowest-order transverse-electric (TE1) mode, the result is a single strong resonant feature with a tunable resonant frequency that is dependent on the geometry of the groove 6,8. This groove can be filled with nonpolar liquid microfluidic samples which cause a shift in the observed resonant frequency that depends on the amount of liquid in the groove and its refractive index 9.
Our technique has an advantage over other terahertz techniques in its simplicity, both in fabrication and implementation, since the procedure can be accomplished with standard laboratory equipment without the need for a clean room or any special fabrication or experimental techniques. It can also be easily expanded to multichannel operation by the incorporation of multiple grooves 10. In this video we will describe our complete experimental procedure, from the design of the sensor to the data analysis and determination of the sample refractive index.

The procedure for implementing a refractive index sensor for terahertz frequencies based on a grooved parallel-plate waveguide geometry is described here. The method yields a measurement of the refractive index of a small volume of liquid through monitoring of the shift in the resonant frequency of the waveguide structure

太赫兹微流控测量中的一个平行板波导传感器

Refractive index (RI) sensing is a powerful noninvasive and label-free sensing technique for the identification, detection and monitoring of microfluidic ...

科研

工程学

Characterization of Surface Modifications by White Light Interferometry: Applications in Ion Sputtering, Laser Ablation, and Tribology Experiments

In materials science and engineering it is often necessary to obtain quantitative measurements of surface topography with micrometer lateral resolution. From the measured surface, 3D topographic maps can be subsequently analyzed using a variety of software packages to extract the information that is needed.
In this article we describe how white light interferometry, and optical profilometry (OP) in general, combined with generic surface analysis software, can be used for materials science and engineering tasks. In this article, a number of applications of white light interferometry for investigation of surface modifications in mass spectrometry, and wear phenomena in tribology and lubrication are demonstrated. We characterize the products of the interaction of semiconductors and metals with energetic ions (sputtering), and laser irradiation (ablation), as well as ex situ measurements of wear of tribological test specimens.
Specifically, we will discuss:
<ol class="lroman">
	<li>Aspects of traditional ion sputtering-based mass spectrometry such as sputtering rates/yields measurements on Si and Cu and subsequent time-to-depth conversion.</li>
	<li>Results of quantitative characterization of the interaction of femtosecond laser irradiation with a semiconductor surface. These results are important for applications such as ablation mass spectrometry, where the quantities of evaporated material can be studied and controlled via pulse duration and energy per pulse. Thus, by determining the crater geometry one can define depth and lateral resolution versus experimental setup conditions.</li>
	<li>Measurements of surface roughness parameters in two dimensions, and quantitative measurements of the surface wear that occur as a result of friction and wear tests.</li>
</ol>
Some inherent drawbacks, possible artifacts, and uncertainty assessments of the white light interferometry approach will be discussed and explained.

White light microscope interferometry is an optical, noncontact and quick method for measuring the topography of surfaces. It is shown how the method can be applied toward mechanical wear analysis, where wear scars on tribological test samples are analyzed; and in materials science to determine ion beam sputtering or laser ablation volumes and depths.

白光干涉表面改性中的应用离子溅射，激光烧蚀，与摩擦学实验表征

In materials science and engineering it is often necessary to obtain quantitative measurements of surface topography with micrometer lateral resolution. ...

Fabrication of Nano-engineered Transparent Conducting Oxides by Pulsed Laser Deposition

Nanosecond Pulsed Laser Deposition (PLD) in the presence of a background gas allows the deposition of metal oxides with tunable morphology, structure, density and stoichiometry by a proper control of the plasma plume expansion dynamics. Such versatility can be exploited to produce nanostructured films from compact and dense to nanoporous characterized by a hierarchical assembly of nano-sized clusters. In particular we describe the detailed methodology to fabricate two types of Al-doped ZnO (AZO) films as transparent electrodes in photovoltaic devices: 1) at low O2 pressure, compact films with electrical conductivity and optical transparency close to the state of the art transparent conducting oxides (TCO) can be deposited at room temperature, to be compatible with thermally sensitive materials such as polymers used in organic photovoltaics (OPVs); 2) highly light scattering hierarchical structures resembling a forest of nano-trees are produced at higher pressures. Such structures show high Haze factor (&gt;80%) and may be exploited to enhance the light trapping capability. The method here described for AZO films can be applied to other metal oxides relevant for technological applications such as TiO2, Al2O3, WO3 and Ag4O4.

We describe the experimental method to deposit nanostructured oxide thin films by nanosecond Pulsed Laser Deposition (PLD) in the presence of a background gas. By using this method Al-doped ZnO (AZO) films, from compact to hierarchically structured as nano-tree forests, can be deposited.

制备纳米设计的脉冲激光沉积透明导电氧化物

Nanosecond Pulsed  Laser Deposition (PLD) in the presence of a background gas allows the deposition  of metal oxides with tunable morphology, structure, ...

Flame Experiments at the Advanced Light Source: New Insights into Soot Formation Processes

The following experimental protocols and the accompanying video are concerned with the flame experiments that are performed at the Chemical Dynamics Beamline of the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory1-4. This video demonstrates how the complex chemical structures of laboratory-based model flames are analyzed using flame-sampling mass spectrometry with tunable synchrotron-generated vacuum-ultraviolet (VUV) radiation. This experimental approach combines isomer-resolving capabilities with high sensitivity and a large dynamic range5,6. The first part of the video describes experiments involving burner-stabilized, reduced-pressure (20-80 mbar) laminar premixed flames. A small hydrocarbon fuel was used for the selected flame to demonstrate the general experimental approach. It is shown how species&#8217; profiles are acquired as a function of distance from the burner surface and how the tunability of the VUV photon energy is used advantageously to identify many combustion intermediates based on their ionization energies. For example, this technique has been used to study gas-phase aspects of the soot-formation processes, and the video shows how the resonance-stabilized radicals, such as C3H3, C3H5, and i-C4H5, are identified as important intermediates7. The work has been focused on soot formation processes, and, from the chemical point of view, this process is very intriguing because chemical structures containing millions of carbon atoms are assembled from a fuel molecule possessing only a few carbon atoms in just milliseconds. The second part of the video highlights a new experiment, in which an opposed-flow diffusion flame and synchrotron-based aerosol mass spectrometry are used to study the chemical composition of the combustion-generated soot particles4. The experimental results indicate that the widely accepted H-abstraction-C2H2-addition (HACA) mechanism is not the sole molecular growth process responsible for the formation of the observed large polycyclic aromatic hydrocarbons (PAHs).

Gas sampling from laboratory-scale flames with online analysis of all species by mass spectrometry is a powerful method to investigate the complex mixture of chemical compounds occurring during combustion processes. Coupled with tunable soft ionization via synchrotron-generated vacuum-ultraviolet radiation, this technique provides isomer-resolved information and potentially fragment-free mass spectra.

火焰在实验的先进光源:全新洞察烟灰形成过程

The following experimental protocols and the accompanying video are concerned with the flame experiments that are performed at the Chemical Dynamics ...

Writing and Low-Temperature Characterization of Oxide Nanostructures

Oxide nanoelectronics is a rapidly growing field which seeks to develop novel materials with multifunctional behavior at nanoscale dimensions. Oxide interfaces exhibit a wide range of properties that can be controlled include conduction, piezoelectric behavior, ferromagnetism, superconductivity and nonlinear optical properties. Recently, methods for controlling these properties at extreme nanoscale dimensions have been discovered and developed. Here are described explicit step-by-step procedures for creating LaAlO3/SrTiO3 nanostructures using a reversible conductive atomic force microscopy technique. The processing steps for creating electrical contacts to the LaAlO3/SrTiO3 interface are first described. Conductive nanostructures are created by applying voltages to a conductive atomic force microscope tip and locally switching the LaAlO3/SrTiO3 interface to a conductive state. A versatile nanolithography toolkit has been developed expressly for the purpose of controlling the atomic force microscope (AFM) tip path and voltage. Then, these nanostructures are placed in a cryostat and transport measurements are performed. The procedures described here should be useful to others wishing to conduct research in oxide nanoelectronics.

Oxide nanostructures provide new opportunities for science and technology. The interfacial conductivity between LaAlO3 and SrTiO3 can be controlled with near-atomic precision using a conductive atomic force microscopy technique. The protocol for creating and measuring conductive nanostructures at LaAlO3/SrTiO3 interfaces is demonstrated.

写作和氧化物纳米结构的低温特性

Oxide nanoelectronics is a rapidly growing field which seeks to develop novel materials with multifunctional behavior at nanoscale dimensions.  Oxide ...

A Method for Studying the Temperature Dependence of Dynamic Fracture and Fragmentation

The dynamic fracture of a body is a late-stage phenomenon typically studied under simplified conditions, in which a sample is deformed under uniform stress and strain rate. This can be produced by evenly loading the inner surface of a cylinder. Due to the axial symmetry, as the cylinder expands the wall is placed into a tensile hoop stress that is uniform around the circumference. While there are various techniques to generate this expansion such as explosives, electromagnetic drive, and existing gas gun techniques they are all limited in the fact that the sample cylinder must be at room temperature. We present a new method using a gas gun that facilitates experiments on cylinders from 150 K to 800 K with a consistent, repeatable loading. These highly diagnosed experiments are used to examine the effect of temperature on the fracture mechanisms responsible for failure, and their resulting influence on fragmentation statistics. The experimental geometry employs a steel ogive located inside the target cylinder, with the tip located about halfway in. A single stage light gas gun is then used to launch a polycarbonate projectile into the cylinder at 1,000 m/sec-1. The projectile impacts and flows around the rigid ogive, driving the sample cylinder from the inside. The use of a non-deforming ogive insert allows us to install temperature control hardware inside the rear of the cylinder. Liquid nitrogen (LN2) is used for cooling and a resistive high current load for heating. Multiple channels of upshifted photon Doppler velocimetry (PDV) track the expansion velocity along the cylinder enabling direct comparison to computer simulations, while High speed imaging is used to measure the strain to failure. The recovered cylinder fragments are also subject to optical and electron microscopy to ascertain the failure mechanism.

Fracture and fragmentation are late stage phenomena in dynamic loading scenarios and are typically studied using explosives. We present a technique for driving expansion using a gas gun which uniquely enables control of both loading rate and sample temperature.

为研究动态断裂及破碎的温度敏感性的方法

The dynamic fracture of a body is a late-stage phenomenon typically studied under simplified conditions, in which a sample is deformed under uniform ...

Experiments on Ultrasonic Lubrication Using a Piezoelectrically-assisted Tribometer and Optical Profilometer

Friction and wear are detrimental to engineered systems. Ultrasonic lubrication is achieved when the interface between two sliding surfaces is vibrated at a frequency above the acoustic range (20 kHz). As a solid-state technology, ultrasonic lubrication can be used where conventional lubricants are unfeasible or undesirable. Further, ultrasonic lubrication allows for electrical modulation of the effective friction coefficient between two sliding surfaces. This property enables adaptive systems that modify their frictional state and associated dynamic response as the operating conditions change. Surface wear can also be reduced through ultrasonic lubrication. We developed a protocol to investigate the dependence of friction force reduction and wear reduction on the linear sliding velocity between ultrasonically lubricated surfaces. A pin-on-disc tribometer was built which differs from commercial units in that a piezoelectric stack is used to vibrate the pin at 22 kHz normal to the rotating disc surface. Friction and wear metrics including effective friction force, volume loss, and surface roughness are measured without and with ultrasonic vibrations at a constant pressure of 1 to 4 MPa and three different sliding velocities: 20.3, 40.6, and 87 mm/sec. An optical profilometer is utilized to characterize the wear surfaces. The effective friction force is reduced by 62% at 20.3 mm/sec. Consistently with existing theories for ultrasonic lubrication, the percent reduction in friction force diminishes with increasing speed, down to 29% friction force reduction at 87 mm/sec. Wear reduction remains essentially constant (49%) at the three speeds considered.

We present a protocol for using a piezoelectrically-assisted tribometer and optical profilometer to investigate the dependence of ultrasonic wear and friction reduction on linear velocity, contact pressure, and surface properties.

使用超声波润滑实验一压电辅助摩擦试验机和光学轮廓

Friction and wear are detrimental to engineered systems. Ultrasonic lubrication is achieved when the interface between two sliding surfaces is vibrated at ...

Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film synthesis) for the purpose of exploratory materials research. Certain materials pose a challenge wherein the traditional bulk Hall bar device fabrication method is insufficient to produce a measureable device for sample transport measurement, principally because the single crystal size is too small to attach wire leads to the sample in a Hall bar configuration. This can be, for example, because the first batch of a new material synthesized yields very small single crystals or because flakes of samples of one to very few monolayers are desired. In order to enable rapid characterization of materials that may be carried out in parallel with improvements to their growth methodology, a method of device fabrication for very small samples has been devised to permit the characterization of novel materials as soon as a preliminary batch has been produced. A slight variation of this methodology is applicable to producing devices using exfoliated samples of two-dimensional materials such as graphene, hexagonal boron nitride (hBN), and transition metal dichalcogenides (TMDs), as well as multilayer heterostructures of such materials. Here we present detailed protocols for the experimental device fabrication of fragments and flakes of novel materials with micron-sized dimensions onto substrate and subsequent measurement in a commercial superconducting magnet, dry helium close-cycle cryostat magnetotransport system at temperatures down to 0.300 K and magnetic fields up to 12 T.

We describe the methodology of mechanical exfoliation and deposition of flakes of novel materials with micron-sized dimensions onto substrate, fabrication of experimental device structures for transport experimentation, and the magnetotransport measurement in a dry helium close-cycle cryostat at temperatures down to 0.300 K and magnetic fields up to 12 T.

对于新材料的低温磁输运测量先进的实验方法

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film ...

The Modular Design and Production of an Intelligent Robot Based on a Closed-Loop Control Strategy

Intelligent robots are part of a new generation of robots that are able to sense the surrounding environment, plan their own actions and eventually reach their targets. In recent years, reliance upon robots in both daily life and industry has increased. The protocol proposed in this paper describes the design and production of a handling robot with an intelligent search algorithm and an autonomous identification function.
First, the various working modules are mechanically assembled to complete the construction of the work platform and the installation of the robotic manipulator. Then, we design a closed-loop control system and a four-quadrant motor control strategy, with the aid of debugging software, as well as set steering gear identity (ID), baud rate and other working parameters to ensure that the robot achieves the desired dynamic performance and low energy consumption. Next, we debug the sensor to achieve multi-sensor fusion to accurately acquire environmental information. Finally, we implement the relevant algorithm, which can recognize the success of the robot&#39;s function for a given application.
The advantage of this approach is its reliability and flexibility, as the users can develop a variety of hardware construction programs and utilize the comprehensive debugger to implement an intelligent control strategy. This allows users to set personalized requirements based on their needs with high efficiency and robustness.

We present a protocol on modular design and production of intelligent robots to help scientific and technical workers design intelligent robots with special production tasks based on personal needs and individualized design.

基于闭环控制策略的智能机器人模块化设计与制作

Intelligent robots are part of a new generation of robots that are able to sense the surrounding environment, plan their own actions and eventually reach ...

Atomic Layer Deposition of Vanadium Dioxide and a Temperature-dependent Optical Model

Vanadium dioxide is a material that has a reversible metal-insulator phase change near 68 &#176;C. To grow VO2 on a wide variety of substrates, with wafer-scale uniformity and angstrom level control of thickness, the method of atomic-layer deposition was chosen. This ALD process enables high-quality, low-temperature (&#8804;150 &#176;C) growth of ultrathin films (100-1000 &#197;) of VO2. For this demonstration, the VO2 films were grown on sapphire substrates. This low temperature growth technique produces mostly amorphous VO2 films. A subsequent anneal in an ultra-high vacuum chamber with a pressure of 7x10-4 Pa of ultra-high purity (99.999%) oxygen produced oriented, polycrystalline VO2 films. The crystallinity, phase, and strain of the VO2 were determined by Raman spectroscopy and X-ray diffraction, while the stoichiometry and impurity levels were determined by X-ray photoelectron spectroscopy, and finally the morphology was determined by atomic force microscopy. These data demonstrate the high-quality of the films grown by this technique. A model was created to fit to the data for VO2 in its metallic and insulating phases in the near infrared spectral region. The permittivity and refractive index of the ALD VO2 agreed well with the other fabrication methods in its insulating phase, but showed a difference in its metallic state. Finally, the analysis of the films&#39; optical properties enabled the creation of a wavelength- and temperature-dependent model of the complex optical refractive index for developing VO2 as a tunable refractive index material.

Thin films (100-1000 &#197;) of vanadium dioxide (VO2) were created by atomic-layer deposition (ALD) on sapphire substrates. Following this, the optical properties were characterized through the metal-insulator transition of VO2. From the measured optical properties, a model was created to describe the tunable refractive index of VO2.

二氧化钒原子层沉积与温度依赖性光学模型

Vanadium dioxide is a material that has a reversible metal-insulator phase change near 68 &#176;C. To grow VO2 on a wide variety of substrates, with ...