作者感谢巴里 g. 杜曼, 罗伯特 a. Icenogle, 胡安. 罗德里格斯, 莫里斯 g. 韦尔奇, 和马林 Siegford 在实验测量方面的技术援助, 以及对吉姆. 克拉克和德克斯特. 拉格朗的计算机模拟帮助。我们感谢夏 LLC 允许在这个项目中使用他们的电子和探测器。这项工作是支持 NIFA ALA 研究合同没有 ALA061-4-15014 "的土壤碳含量的精确地理空间测绘农业生产力和生命周期管理"。

1. 构建 ins 系统 <ol> <li> 使用在 图 1 中显示的常规 ins 系统几何. </li> </ol>
 <img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56270/56270fig1.jpg"/> 图 1 。 INS 系统几何 <a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56270/56270fig1large.jpg" target="_blank"> 请单击此处查看此图的较大版本. </a> 
<ol start="2"> <li> 使用在 图 2 中显示的 INS 系统设计. 10 </li> </ol> <img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56270/56270fig2.jpg"/> 图 2 。 INS 系统概述 
 A) 第一块包含中子发生器、中子探测器和电力系统; B) 第二块包含三奈 (Tl) 探测器; C) 第三个区块包含系统操作设备; D) 显示单个组件的第一个块的一般视图;和 E) 关闭伽玛探测器的视图。 10 <a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56270/56270fig2large.jpg" target="_blank"> 请单击此处查看此图的较大版本. </a> 
<ol start="3"> <li> 在 INS 系统中使用三块 (见附录)。
	<ol> <li> 对于第一个块 (a), 使用中子发生器 (NG) 和电源系统 ( 图 2A 和 2D )。该发生器的脉冲中子输出将为 10 7 -10 8 n/秒, 中子能量为14兆伏特。电力系统将包括四电池 (12 伏, 105 Ah), 直流交流逆变器和充电器。该区块还将包含铁 (10 厘米 x 20 cm x 30 厘米) 和硼酸 (5 cm x 20 cm x 30 cm) 屏蔽, 以保护γ探测器免受中子辐照. 
		注: 中子探测器也包括在该区块中, 用于检查 NG 是否正常工作. </li>
		<li> 对于第二个块 (B), 使用伽玛射线测量设备 ( 图 2B 和 2E )。该区块将包含三 12.7 cm x 12.7 cm x 15.2 cm 闪烁奈 (Tl) 探测器与相应的电子学。探测器的外部尺寸与电子学将测量 15.2 cm x 15.2 cm x 46 cm. </li>
		<li> 对于第三个块 (C), 使用便携式计算机控制中子发生器 (使用 DNC 软件)、探测器和数据采集系统 ( 图 2C ). </li>
	</ol> </li> </ol> 2。警告和个人要求 <ol> <li> 让 INS 系统的每个用户都通过辐射训练. </li>
	<li> 确保操作 NG 的每个人都携带辐射监测徽章。在测量期间, 受限区域边界 (#62; 20 和 #181; Sv/h) 在 ng 附近将有辐射标志与词和 #34; 小心, 辐射区域. 和 #34; 禁区的所有边缘将不少于4米从 NG. </li>
	<li> 紧急情况下, 立即推 #34; 紧急中断和 #34; 在 ng 上的按钮, 从 ng 中删除该密钥, 然后从电源中拔下 ng. </li>
</ol> 3。测试 INS 系统的准备 <ol> <li> 检查电源系统。充电器上的电源电平指示器将是绿色的, 或者超过3盏红灯必须照亮。如果没有, 将充电器连接到电源插座, 等到电池完全充电 (绿灯亮亮), 或直到达到可接受的功率电平 (和 #8805; 3 盏红灯亮起). </li>
	<li> 打开逆变器 (绿灯灯照明) 和笔记本电脑. </li>
	<li> 运行便携式计算机上的数据采集程序以操作伽玛探测器, 并检查每个检测器所需的参数。这些参数的值将在 INS 系统测试之前定义和记录。
	<ol> <li> 将 Cs-137 控制源 (任何类型) 放在探测器的 5-15 cm 内. </li>
		<li> 启动光谱采集 1-3 分钟; 检查所有探测器的 662 Cs-137 峰值的质心。他们必须在同一个频道。如果不是, 使用数据获取程序的能量系数刻度, 通过改变值来调整662质心峰值. </li>
	</ol> </li> <li> 使用特殊键打开 NG。NG 上的指示灯将照亮绿色和黄色. </li>
</ol> 4。INS 系统的校准 <ol> <li> 准备4坑大小 1.5 m x 1.5 m x 0.6 m 与均匀的沙子-碳混合物 ( 图 3 )。碳含量为0、2.5、5和 10 w%. 
	注: 混凝土搅拌机用于建筑砂和椰子壳组成的合成土 (100% 碳含量, 平均粒径和 #60; 0.5 毫米)。这些混合物的均一性在视觉上被确定. </li>
</ol> <img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/56270/56270fig3.jpg"/> 图 3 。 坑用沙子和坑的看法与 10 Cw% 沙子-碳混合物 。<a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56270/56270fig3large.jpg" target="_blank"> 请单击此处查看此图的较大版本. </a> 
<ol start="2"> <li> 使用以下步骤在凹坑上进行测量。
	<ol> <li> 手动将 INS 系统放置在坑上, 或用适当的车辆拖曳。定位 INS 系统, 使中子源的投射集中在坑上. </li>
		<li> 运行 NG 发生器的便携式计算机上的 DNC 软件。在 DNC 程序屏幕右侧的故障列中, 所有的灯都将照亮绿色;如果没有, 请单击 "清除" 按钮。插入以下参数: 对于脉冲参数-频率5赫, 占空比 25%, 延时0和 #181; s, 扩展2和 #181;对于梁-高电压 50 kV, 光束电流50和 #181; A (请注意, 根据特定的 INS 系统设置和任务, 这些参数可能会有所不同)。
		<ol> <li> 激活 DNC 程序屏幕上的开关, 等待 NG 进入工作状态, 在那里, 高压和光束电流将进入与输入值对应的稳定值;油藏电流也会趋于稳定值. </li>
		</ol> </li> <li> 运行便携式计算机上的数据采集软件以操作伽玛探测器。通过运行1小时的数据采集程序启动频谱采集。两种光谱采集过程 (INS 和 #38; 跨国公司和跨国公司) 将出现在屏幕上. </li>
		<li> 1 小时后, 停止频谱采集并将频谱保存到硬盘 (文件 |保存 MCA 数据 |选择文件夹并输入文件名. 
		注: 将有两个保存的频谱 (跨国公司和 INS) 与文件扩展名. mca 和 _gated 分别). </li>
		<li> 选择第二个探测器 (单击左上角的箭头) 并保存此探测器的频谱。对第三个探测器也这样做. </li>
		<li> 单击文件 |退出以关闭软件. </li>
		<li> 通过关闭 dnc 程序屏幕上的开关来关闭 dnc 软件. </li>
		<li> 对其他坑重复步骤 4.2.1 4.2.7. </li>
		<li> 使用特殊键关闭 NG。NG 上的指示灯会变暗. </li>
	</ol> </li> <li> 通过将整个 ins 系统提升到地面上方大于4米的距离并远离任何大型对象来确定 ins 系统的背景光谱, 并重复数据获取步骤 4.2.2-4.2.9. </li>
	<li> 数据处理 <ol> <li> 使用电子表格程序打开保存在步骤4.2.4 中的数据文件。分别查找28、27和30行中的输出和输入计数率 (OCR 和民事代表) 和实时 (RT) 的值. </li>
		<li> 计算 INS 和 #38 的生命时间 (LT); 跨国公司和跨国公司光谱为所有测量作为 LT 我 = OCR i /民事代表 i 和 #183; RT i (1), 在那里进行 OCR i 和民事代表 i 是 i/o 测量和 RT i 是真实的输出和输入计数率时间的测量. </li>
		<li> 通过将光谱 (电子表格中的33-2080 行) 除以对应的 LT 来计算每秒计数 (cps) 的伽玛谱. </li>
		<li> 计算每个坑的对应测量的净 INS 光谱为 
		净 ins 频谱 = (ins 和 #38; 跨国公司-跨国公司) 中继站 -(ins 和 #38; 跨国公司-跨国公司) Bkg (2) </li> <li> 在每个坑的网络 INS 频谱中查找伽玛峰1.78 兆伏特 ( 28 Si) 和4.44 兆伏特 ( 12 c), 并计算峰值区域 (4.44 兆电子伏特 c 峰值区域, 1.78 兆伏特 Si 峰顶区域) 使用伊戈尔软件。
		<ol> <li> 通过双击图标打开软件。在表中插入第一个净 INS 频谱. </li>
			<li> 单击窗口 |新图表 |从目标 |#34; 文件名和 #34; |做吧。频谱出现在图形窗口中。点击图 |显示信息。带有 a 和 B 标记的窗口显示在 "图形" 窗口下. </li>
			<li> 将鼠标指针放在符号 A 上, 按下鼠标左键, 并将光标拖动到1.78 兆伏特峰值的左侧的频谱上。将鼠标指针放在符号 B 上, 按下鼠标左键, 将光标拖动到1.78 兆伏特峰值的右侧频谱上. </li>
			<li> 单击分析 |多峰配合 |开始新的多峰值匹配 |从目标 |继续.在被标记的弹出窗口使用图表游标 |基线线性 |现在自动定位峰值 |做它 |峰值结果。峰值区域显示在弹出窗口中. </li>
			<li> 对4.44 兆伏特峰值重复相同的操作. </li>
			<li> 使用剩余的净 INS 频谱重复以前的所有操作. </li>
		</ol> </li> <li> 通过公式查找每个坑的净碳峰值区域 净 c 峰值区域 i = 4.44 兆伏特 c 峰值区域 i -0.058 和 #183; 1.78 兆伏特 Si 峰值区域 i (3) </li> <li> 建立 INS 系统的校准线作为直接支柱ortional 碳峰面积与碳浓度的关系, 以重量百分比表示。
		<ol> <li> 在伊戈尔软件中打开新表: 单击窗口 |新表。在第一列中输入坑碳浓度值, 第二列中的相应净 C 峰值区域. </li>
			<li> 绘制网 C 峰值区 vs 坑碳浓度: 单击窗口 |新图。选择净 C 峰面积为 YWave, 碳浓度为 XWave。单击 "执行"。这些点出现在图表上. </li>
			<li> 生成校准行: 单击分析 |曲线拟合 |功能线 |从目标 |做吧。校准线和校准系数 (k) 将出现在窗口中. </li>
		</ol> </li> </ol> </li> </ol> 5。在静态模式下进行野外土壤测量 <ol> <li> 根据步骤3准备用于测量的 INS 系统. </li>
	<li> 将系统放置在需要手动或使用合适的车辆拖曳土壤碳含量分析的站点上。定位 INS 系统, 使中子源的投射集中在被测量的站点上. </li>
	<li> 执行以下步骤 4.2.2-4.2.9 和 4.4.1-4.4.6 用于确定研究站点的净 C 峰值区域. </li>
	<li> 使用校准系数计算重量百分比中的碳浓度 
	<img alt="Equation 1" src="/files/ftp_upload/56270/56270eq1.jpg"/> </li> </ol> 6. 在扫描模式下进行野外土壤测量 <ol> <li> 评估 INS 系统将在该域中旅行的路径, 而计算旅行速度 (和 #8804; 5 公里/小时)、字段大小、INS 系统占地面积 (半径1米) 和测量时间 (1 h), 使移动轨迹最终覆盖整个领域。为方便起见, 将标志放置在沿外围区域的转弯处. </li>
	<li> 根据步骤3准备测试 INS 系统. </li>
	<li> 执行以下步骤的操作 4.2.2-4.2.3. </li>
	<li> 遵循预定的旅行路径1小时 </li>
	<li> 执行以下步骤 4.2.4-4.2.9 和 4.4.1-4.4.6 用于确定所研究字段的净 C 峰值区域. </li>
	<li> 使用校准系数按公式4计算重量的碳浓度%. </li>
</ol>

<ol>
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作者没有什么可透露的。

在以前的研究人员建立的基础上, NSDL 工作人员讨论了在实际和成功地使用这项技术在现实世界领域中的关键问题。最初, NSDL 研究人员证明了在确定净碳峰值区时, 需要考虑 INS 系统的背景信号。11另一项努力表明, 净碳峰值面积是通过直接比例依赖性来表征上部 10 cm 土层 (不论碳深度分布形状) 的平均碳重量百分比。此外, 为 INS 系统校准所需的设备 (即, 1.5 m x 1.5 m x 0.6 m 坑与不同的沙子碳混合物) 被构造了和校准规程必要为实际世界应用被开发和执行。由此产生的标定线使其能够从实测的净碳峰区中测定土壤碳含量。虽然 NSDL 研究人员已经纳入了许多 ins 系统的设计改进, 最近加入的伽玛探测器的磁场屏蔽允许实际使用 ins 系统扫描模式进行大规模的土壤碳调查。
应用 INS 法进行土壤碳分析的经验揭示了几种关键的协议步骤。为了获得正确的测量结果, 使用参考源仔细检查和调整探测器参数是至关重要的;这对于系统稳定性和再现测量结果是非常重要的。系统背景和校准测量也是准确测定土壤碳含量的关键步骤。请注意, 对于系统背景和校准测量, 探测器参数应相同。为了提高校准系数的准确度, 进行几个小时的校准测量 (坑和系统背景) 是适宜的。在探测器上安装磁性屏幕对于准确测量扫描模式至关重要, 因为屏蔽探测器由于地球磁场的影响产生了非常大的误差。此外, 磁屏蔽改善了静态模式的结果。
在野外测绘过程中, 应用 INS 法与 "金本位" 直流法的重要性进行了论证。用 INS 方法定义碳含量的速度比直流法大30倍。介绍部分还讨论了 INS 方法的其他优点。
尽管 ins 和 DC ("金本位") 方法之间已显示出协议, 但 ins 技术的当前修改有一个主要的限制, 即最小可级别 (1.5 w%)。由于土壤碳含量可以小于此, 未来的努力将集中在提高 INS 系统的灵敏度, 增加伽玛探测器的数量和优化整体系统设计或应用目标中子方法。13
尽管存在这一限制, 可建议对 INS 系统进行现有的修改, 以确定各个地点的土壤碳含量, 并对野外地形的碳分布进行测绘。未来可能的工作使用 INS 方法可以探索测量其他土壤元素, 如氮, 铁, 氢。

需要了解土壤碳含量, 以优化土壤生产力和利润率, 理解农用土地利用做法对土壤资源的影响, 并评估碳螯合的策略1, 2,3,4。土壤碳是土壤质量的普遍指标5。为土壤碳量测量开发了几种方法。干式燃烧 (DC) 是多年来使用最广泛的方法6;该方法是基于野外样品收集和实验室处理和测量, 具有破坏性, 劳动强度大, 耗时。两个新的方法是激光诱导击穿光谱学, 和近和中红外光谱学7。这些方法也是破坏性的并且只分析非常近表面土壤层数 (0.1-1 cm 土壤深度)。此外, 这些方法只对小样本量 (60 厘米3的 DC 方法) 和 0.01-10 cm3的红外光谱方法的碳含量进行点测量。这样的点测量使得很难将结果推断出场或横向尺度。因为这些方法是破坏性的, 所以重复的测量也是不可能的。
前文国家实验室的研究人员建议应用中子技术进行土壤碳分析 (INS 方法)7,8,9。这一初步的努力发展的理论和实践中使用中子伽马分析土壤碳测量。从2013年开始, 这项工作继续在美国农业部-ARS 国家土壤动力学实验室 (NSDL)。在过去10年中, 这种技术应用的扩大是由于两个主要因素: 相对便宜的商用中子发生器、伽玛探测器和相应的电子软件的可用性;和状态的艺术中子-原子核相互作用参考数据库。这种方法比其他方式有几个优点。一个 INS 系统, 放置在一个平台上, 可以操纵任何类型的领域, 需要测量。这种非破坏性的原位方法可以分析大的土壤体积 (约300千克), 可以通过少量的测量来对整个农业领域进行插值。这个 INS 系统也能够在扫描模式下运行, 它可以根据预先确定的域或横向网格的扫描来决定一个区域的平均碳含量。

<table border="0" cellpadding="0" cellspacing="0" width="717">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:195px;">Neutron Generator</td>
			<td style="width:327px;">Thermo Fisher Scientific, Colorado Springs, CO 
			DNC software</td>
			<td style="width:125px;">MP320</td>
			<td style="width:72px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Gamma-detector:</td>
			<td></td>
			<td>na</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">- NaI(Tl) crystal</td>
			<td>Scionix USA, Orlando, FL</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">- Electronics</td>
			<td>XIA LLC, Hayward, CA</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">- Software</td>
			<td>ProSpect</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Battery</td>
			<td>Fullriver Battery USA, Camarillo, CA</td>
			<td>DC105-12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Invertor</td>
			<td>Nova Electric, Bergenfield, NJ</td>
			<td>CGL 600W-series</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Charger</td>
			<td>PRO Charging Systems, LLC, LaVergne, TN</td>
			<td>PS4</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Block of Iron</td>
			<td>Any</td>
			<td>na</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Boric Acid</td>
			<td>Any</td>
			<td>na</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Laptop</td>
			<td>Any</td>
			<td>na</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">mu-metal</td>
			<td>Magnetic Shield Corp., Bensenville, IL</td>
			<td>&#160;MU010-12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Construction sand</td>
			<td>Any</td>
			<td>na</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Coconut shell</td>
			<td>General Carbon Corp., Patterson, NJ</td>
			<td>GC 8 X 30S</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">Reference Cs-137 source</td>
			<td>Any</td>
			<td>na</td>
			<td></td>
		</tr>
	</tbody>
</table>

measurements of soil carbon by neutron-gamma analysis in static and scanning modes

本文介绍了非弹性中子散射 (INS) 法在土壤碳分析中的应用, 其基础是在中子与土壤元素相互作用时所产生的伽玛射线的登记和分析。ins 系统的主要部分是脉冲中子发生器, 奈 (Tl) 伽玛探测器, 分裂电子学, 以分离伽马谱由于 INS 和热中子捕获 (跨国公司) 的过程, 和软件的伽马谱采集和数据处理。这种方法比其他方法有几个优点, 因为它是一种非破坏性的原位方法, 用于测量大容量土壤中的平均碳含量, 地受土壤碳的局部剧烈变化的影响, 可用于静止或扫描模式。INS 方法的结果是, 在静止状态下, 从一个站点的碳含量为 2.5-3 m2 , 或者扫描体制中所遍历区域的平均碳含量。当前 INS 系统的测量范围是和 #62; 1.5 碳重量% (标准偏差± 0.3 w%) 在上部 10 cm 土壤层数为 1 hmeasurement。

土壤和 #38; 跨国公司和跨国公司的伽马谱
在图 4中显示了测量的土壤伽玛谱的一般视图。光谱由连续背景上的一组峰组成。主要的兴趣峰值质心在4.44 兆伏特和1.78 兆伏特在 INS 和 #38; 跨国公司光谱。第二峰可归因于土壤中的硅核, 第一峰是碳和硅核的重叠峰值。本文介绍了从这些光谱中提取净碳峰面积的方法。这一程序应用于所有情况下, 以确定净碳峰面积完全由于碳核。11
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/56270/56270fig4.jpg">
图 4。由 INS 系统测量的典型土壤伽马谱.<a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56270/56270fig4large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
INS 系统背景测量
在图 5中显示了在不同的系统海拔高度测量的净 INS 光谱。11峰值区域与具有高度的质心在1.78 兆伏特、4.44 兆伏特和6.13 兆伏特 (氧峰值) 之间的依赖关系在图 6中进行了说明。如图所示, 光谱不再在地表以上4米以上的高度变化。因此, 在高度大于4米的光谱可以归因于伽马谱, 出现由于中子与系统建筑材料的相互作用。我们用这些光谱 (在 H=6 m) 作为系统背景谱在我们的数据处理。
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/56270/56270fig5.jpg">
图 5。a)在不同 ins 系统高度之上的网络 ins 频谱;b)网络 INS 谱的片段大约1.78 兆伏特;和c)片段的净 INS 谱约4.44 兆伏特。箭头选定增加的高度。11 <a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56270/56270fig5large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/56270/56270fig6.jpg">
图 6。峰值区域与质心的依赖关系在 1.78, 和4.44 兆伏特在 ins 系统的频谱中, 在/d.<a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56270/56270fig6large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
校准
ins 系统校准期间生成的网络 ins 频谱显示在图 7a中。11在1.78 兆伏特和4.44 兆伏特峰值附近的净 INS 谱片段分别显示在图 7b和7c的更大范围内。可以看出, 4.44 兆伏特的质心的峰值随着坑内碳含量的增加而增加。同时, 以1.78 兆伏特为中心的峰值随着凹坑中的碳增加而略有下降。在图 8中显示了净碳峰值区 (从这些光谱中计算) 与坑中碳含量 (以重量表示%) 的相关性.11正如可以看到的, 这可以由直接比例依赖关系通过原点 (0, 0 点) 在实验误差范围内表示。此依赖性用于校准进一步的测量。
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/56270/56270fig7.jpg">
图 7。a)用砂碳混合物在0、2.5、5和10碳 w% (均匀混合物) 上的凹坑光谱;b)在1.78 兆伏特左右的净 INS 谱片段;c)在4.44 兆伏特左右的网络 INS 片段。11 <a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56270/56270fig7large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 8" class="xfigimg" src="/files/ftp_upload/56270/56270fig8.jpg">
图 8。网碳峰值区域与凹坑中碳浓度的相关性 (点与误差线), 以及 INS 系统校准行 (实线).11 <a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56270/56270fig8large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
静态模式下碳含量的现场测量
静态模式下的碳含量测量在几个现场进行。结果从阿拉巴马农业实验站山麓研究单位, 阵营山, AL (110 m x 30 m) 在表 1中介绍。现场测量在3乘5网格的交叉点进行, 网格线之间的距离相等 (总共15站点)。从表中可以看出, 单个交点的碳含量在1.4 到 3.1 w% 之间变化, 所有测量的标准偏差为 0.3 w%。为了比较, 在每个地点也采取破坏性土壤样品, 用标准直流法测定土壤碳含量。这些数据也显示在表 1中。两个数据集的比较表明, 每个位置的方法和整个领域的平均值都有很好的一致性。
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td rowspan="4">位置</td>
			<td></td>
			<td colspan="3" rowspan="2">INS 测量</td>
			<td colspan="3" rowspan="2">干燃烧测量</td>
		</tr>
		<tr>
			<td>网站#</td>
		</tr>
		<tr>
			<td></td>
			<td rowspan="2">c</td></tr></tbody></table>炭, w%
			<td>性病,</td>
			<td>绘图平均值</td>
			<td rowspan="2">碳、w%</td>
			<td>性病,</td>
			<td>绘图平均值</td>
		
		<tr>
			<td></td>
			<td>w%</td>
			<td>±STD, w%</td>
			<td>w%</td>
			<td>±STD, w%</td>
		</tr>
		<tr>
			<td rowspan="15">阵营小山</td>
			<td>OF1</td>
			<td>2。2</td>
			<td>0.29</td>
			<td rowspan="15">2.23±0.45</td>
			<td>2.85</td>
			<td>0.25</td>
			<td rowspan="15">2.25±0.51</td>
		</tr>
		<tr>
			<td>OF2</td>
			<td>2.51</td>
			<td>0.29</td>
			<td>2.54</td>
			<td>0.31</td>
		</tr>
		<tr>
			<td>OF3</td>
			<td>1.76</td>
			<td>0.22</td>
			<td>1.91</td>
			<td>0.13</td>
		</tr>
		<tr>
			<td>OF4</td>
			<td>1.88</td>
			<td>0.23</td>
			<td>2.99</td>
			<td>0.94</td>
		</tr>
		<tr>
			<td>OF5</td>
			<td>2.82</td>
			<td>0.25</td>
			<td>3.03</td>
			<td>0.37</td>
		</tr>
		<tr>
			<td>OF6</td>
			<td>2.15</td>
			<td>0.21</td>
			<td>1.99</td>
			<td>0.26</td>
		</tr>
		<tr>
			<td>OF7</td>
			<td>2.77</td>
			<td>0.32</td>
			<td>1.92</td>
			<td>0.41</td>
		</tr>
		<tr>
			<td>OF8</td>
			<td>2.52</td>
			<td>0.25</td>
			<td>2.44</td>
			<td>0.15</td>
		</tr>
		<tr>
			<td>OF9</td>
			<td>2.06</td>
			<td>0.26</td>
			<td>1.79</td>
			<td>0.27</td>
		</tr>
		<tr>
			<td>OF10</td>
			<td>2.17</td>
			<td>0.27</td>
			<td>2.25</td>
			<td>0.45</td>
		</tr>
		<tr>
			<td>OF11</td>
			<td>2.39</td>
			<td>0.22</td>
			<td>2.23</td>
			<td>0。3</td>
		</tr>
		<tr>
			<td>OF12</td>
			<td>3.11</td>
			<td>0.31</td>
			<td>2.91</td>
			<td>0.47</td>
		</tr>
		<tr>
			<td>OF13</td>
			<td>1.44</td>
			<td>0.25</td>
			<td>1.49</td>
			<td>0.42</td>
		</tr>
		<tr>
			<td>OF14</td>
			<td>1.93</td>
			<td>0.29</td>
			<td>1。8</td>
			<td>0.19</td>
		</tr>
		<tr>
			<td>OF15</td>
			<td>1.86</td>
			<td>0.27</td>
			<td>1.67</td>
			<td>0.25</td>
		</tr>
	

表 1.在上部土层中, 通过干燃烧和 INS 法的平均重量百分比.
根据 INS 和 DC 方法 (图 9和10) 比较该字段的碳分布图是很有趣的。这两个地图看起来非常相似, 但应该注意的是, 2 天的 INS 映射, 而〜2月被要求处理样品, 以创建 DC 地图。
<img alt="Figure 9" class="xfigimg" src="/files/ftp_upload/56270/56270fig9.jpg">
图 9。基于 INS 方法的营丘场碳分布图.<a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56270/56270fig9large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 10" class="xfigimg" src="/files/ftp_upload/56270/56270fig10.jpg">
图 10。基于 DC 方法的阵营山场碳分布图.<a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56270/56270fig10large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
扫描模式中碳含量的现场测量
土壤科学家通常对测定大面积的碳含量有兴趣(例如, 100 米 x 100 米)。使用 ins 扫描模式确定 100 m x 100 m 字段的平均碳含量, 而不是在10米之外的位置确定碳 (需要每测量1小时)。在扫描模式下, 可以在传递整个字段时对 INS 进行测量。这种扫描测量可以在静态模式 (1 h) 中测量单个位置所需的相同时间内进行。本文给出了 INS 扫描模式的证明和原理。
值得注意的是, 第一次尝试测量碳的扫描模式是不太满意。所获得的扫描光谱明显不同于 INS 和 #38; 跨国公司和跨国公司的静态模式谱;在静态模式中, 峰值面积比观测值低得多, 而兴趣峰更宽、更短。调查确定, 这种失真是由于地球磁场对伽玛探测器的光电倍增管的影响12。为了解决这个问题, 使用了一个磁屏 (mu 金属) 来屏蔽伽玛探测器。测试表明, Co-60 控制源的伽马谱几乎是完全相同的, 无论被屏蔽伽玛探测器的方向 (垂直, 水平, 倾斜), 而峰值的质心和峰值宽度的变化取决于方向屏蔽探测器结果表明, 利用磁屏可以抑制地球磁场对光电倍增管的影响。磁屏蔽消除了峰值展宽, 产生了与静态模式谱非常相似的扫描伽马谱。
为了比较静态和扫描模式, 在 15 m x 45 m 场内的5随机位置进行了碳含量的静态测量 (每1小时), 并在具有相当均匀碳含量的同一字段上进行了扫描模式 (1 h 总计) 的测量。图 11说明了显示各个测量位置和扫描路径的字段的映射。5静态模式位置和扫描模式的网络 INS 频谱显示在图 12中。如图 12所示, 扫描模式频谱看起来类似于静态模式谱, 并在所有静态频谱中都属于中端。
<img alt="Figure 11" class="xfigimg" src="/files/ftp_upload/56270/56270fig11.jpg">
图 11.显示静态测量位置 (星) 和扫描路径 (行) 的字段的映射。<a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56270/56270fig11large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 12" class="xfigimg" src="/files/ftp_upload/56270/56270fig12.jpg">
图 12.静态和扫描模式的净 ins 谱; 插页是一个片段的净 ins 频谱约4.44 兆伏特。<a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56270/56270fig12large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
净碳峰值面积计算的结果显示在表 2中。从所提出的数据可以看出, 在扫描模式下测量的净碳峰面积值与实验误差范围内的平均静态模式值一致。这些结果证明, INS 扫描模式的测量可以用来定义一个领域的平均碳含量。值得注意的是, 5 h 用于确定静态模式下的平均碳含量, 而在扫描模式中只需要 1 h。
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td rowspan="2">模式</td>
			<td rowspan="2">网站#</td>
			<td>净碳</td>
			<td>性病,</td>
			<td>字段平均值</td>
		</tr>
		<tr>
			<td>峰区, cps</td>
			<td>cps</td>
			<td>±STD, cps</td>
		</tr>
		<tr>
			<td rowspan="5">静态</td>
			<td>1</td>
			<td>64。8</td>
			<td>3。9</td>
			<td rowspan="5">63.3±3。8</td>
		</tr>
		<tr>
			<td>2</td>
			<td>58。1</td>
			<td>3。5</td>
		</tr>
		<tr>
			<td>3</td>
			<td>65。4</td>
			<td>3。4</td>
		</tr>
		<tr>
			<td>4</td>
			<td>68。9</td>
			<td>4。1</td>
		</tr>
		<tr>
			<td>5</td>
			<td>59。4</td>
			<td>4。1</td>
		</tr>
		<tr>
			<td>扫描</td>
			<td>结束领域</td>
			<td>64。4</td>
			<t></t></tr></tbody></table>d > 3。3
			<td>64.4±3。3</td>
		
	

表 2.静态和扫描模式的净碳峰值区域.

Watch this Scientific Journal Video about Measurements of Soil Carbon by Neutron-Gamma Analysis in Static and Scanning Modes at JoVE.com

Measurements of Soil Carbon by Neutron-Gamma Analysis in Static and Scanning Modes

静态和扫描模式下中子伽马分析法测量土壤碳

在这里, 我们提出了使用中子伽玛技术进行单点测量 (静态模式) 或场平均值 (扫描模式) 的土壤碳的原位测量的协议。我们还描述系统建设和详细的数据处理程序。

The herein described application of the inelastic neutron scattering (INS) method for soil carbon analysis is based on the registration and analysis of ...

measurements-soil-carbon-neutron-gamma-analysis-static-scanning

Nanyang Technological University

Research

JoVE Journal

Engineering

7.2K 次观看.  Agricultural Research Service, United States Department of Agriculture. 在这里, 我们提出了使用中子伽玛技术进行单点测量 (静态模式) 或场平均值 (扫描模式) 的土壤碳的原位测量的协议。我们还描述系统建设和详细的数据处理程序。

视频: Measurements of Soil Carbon by Neutron-Gamma Analysis in Static and Scanning Modes

Fabrication, Densification, and Replica Molding of 3D Carbon Nanotube Microstructures

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip devices, and their applications. In particular, capabilities for cost-effective fabrication of polymer microstructures were transformed by the advent of soft lithography and other micromolding techniques 1, 2, and this led a revolution in applications of microfabrication to biomedical engineering and biology. Nevertheless, it remains challenging to fabricate microstructures with well-defined nanoscale surface textures, and to fabricate arbitrary 3D shapes at the micro-scale. Robustness of master molds and maintenance of shape integrity is especially important to achieve high fidelity replication of complex structures and preserving their nanoscale surface texture. The combination of hierarchical textures, and heterogeneous shapes, is a profound challenge to existing microfabrication methods that largely rely upon top-down etching using fixed mask templates. On the other hand, the bottom-up synthesis of nanostructures such as nanotubes and nanowires can offer new capabilities to microfabrication, in particular by taking advantage of the collective self-organization of nanostructures, and local control of their growth behavior with respect to microfabricated patterns. 
Our goal is to introduce vertically aligned carbon nanotubes (CNTs), which we refer to as CNT "forests", as a new microfabrication material. We present details of a suite of related methods recently developed by our group: fabrication of CNT forest microstructures by thermal CVD from lithographically patterned catalyst thin films; self-directed elastocapillary densification of CNT microstructures; and replica molding of polymer microstructures using CNT composite master molds. In particular, our work shows that self-directed capillary densification ("capillary forming"), which is performed by condensation of a solvent onto the substrate with CNT microstructures, significantly increases the packing density of CNTs. This process enables directed transformation of vertical CNT microstructures into straight, inclined, and twisted shapes, which have robust mechanical properties exceeding those of typical microfabrication polymers. This in turn enables formation of nanocomposite CNT master molds by capillary-driven infiltration of polymers. The replica structures exhibit the anisotropic nanoscale texture of the aligned CNTs, and can have walls with sub-micron thickness and aspect ratios exceeding 50:1. Integration of CNT microstructures in fabrication offers further opportunity to exploit the electrical and thermal properties of CNTs, and diverse capabilities for chemical and biochemical functionalization 3.

We present methods for fabrication of patterned microstructures of vertically aligned carbon nanotubes (CNTs), and their use as master molds for production of polymer microstructures with organized nanoscale surface texture. The CNT forests are densified by condensation of solvent onto the substrate, which significantly increases their packing density and enables self-directed formation of 3D shapes.

制备，致密，副本三维碳纳米管微结构成型

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip ...

科研

工程学

Speciation and Bioavailability Measurements of Environmental Plutonium Using Diffusion in Thin Films

The biological uptake of plutonium (Pu) in aquatic ecosystems is of particular concern since it is an alpha-particle emitter with long half-life which can potentially contribute to the exposure of biota and humans. The diffusive gradients in thin films technique is introduced here for in-situ measurements of Pu bioavailability and speciation. A diffusion cell constructed for laboratory experiments with Pu and the newly developed protocol make it possible to simulate the environmental behavior of Pu in model solutions of various chemical compositions. Adjustment of the oxidation states to Pu(IV) and Pu(V) described in this protocol is essential in order to investigate the complex redox chemistry of plutonium in the environment. The calibration of this technique and the results obtained in the laboratory experiments enable to develop a specific DGT device for in-situ Pu measurements in freshwaters. Accelerator-based mass-spectrometry measurements of Pu accumulated by DGTs in a karst spring allowed determining the bioavailability of Pu in a mineral freshwater environment. Application of this protocol for Pu measurements using DGT devices has a large potential to improve our understanding of the speciation and the biological transfer of Pu in aquatic ecosystems.

The technique of diffusive gradients in thin films (DGT) is proposed for speciation studies of plutonium. This protocol describes diffusion experiments probing the behavior of Pu(IV) and Pu(V) in presence of organic matter. DGTs deployed in a karstic spring allow assessment of the bioavailability of Pu.

环境钚的薄膜弥散形态和生物利用度测量

The biological uptake of plutonium (Pu) in aquatic ecosystems is of particular concern since it is an alpha-particle emitter with long half-life which can ...

Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis

Nuclear reaction analysis (NRA) via the resonant 1H(15N,&#945;&#947;)12C reaction is a highly effective method of depth profiling that quantitatively and non-destructively reveals the hydrogen density distribution at surfaces, at interfaces, and in the volume of solid materials with high depth resolution. The technique applies a 15N ion beam of 6.385 MeV provided by an electrostatic accelerator and specifically detects the 1H isotope in depths up to about 2 &#956;m from the target surface. Surface H coverages are measured with a sensitivity in the order of ~1013 cm-2 (~1% of a typical atomic monolayer density) and H volume concentrations with a detection limit of ~1018 cm-3 (~100 at. ppm). The near-surface depth resolution is 2-5 nm for surface-normal 15N ion incidence onto the target and can be enhanced to values below 1 nm for very flat targets by adopting a surface-grazing incidence geometry. The method is versatile and readily applied to any high vacuum compatible homogeneous material with a smooth surface (no pores). Electrically conductive targets usually tolerate the ion beam irradiation with negligible degradation. Hydrogen quantitation and correct depth analysis require knowledge of the elementary composition (besides hydrogen) and mass density of the target material. Especially in combination with ultra-high vacuum methods for in-situ target preparation and characterization, 1H(15N,&#945;&#947;)12C NRA is ideally suited for hydrogen analysis at atomically controlled surfaces and nanostructured interfaces. We exemplarily demonstrate here the application of 15N NRA at the MALT Tandem accelerator facility of the University of Tokyo to (1) quantitatively measure the surface coverage and the bulk concentration of hydrogen in the near-surface region of a H2 exposed Pd(110) single crystal, and (2) to determine the depth location and layer density of hydrogen near the interfaces of thin SiO2 films on Si(100).

We illustrate the application of 1H(15N,&#945;&#947;)12C resonant nuclear reaction analysis (NRA) to quantitatively evaluate the density of hydrogen atoms on the surface, in the volume, and at an interfacial layer of solid materials. The near-surface hydrogen depth profiling of a Pd(110) single crystal and of SiO2/Si(100) stacks is described.

通过与核反应分析深度剖面的表面和界面层和颗粒材料氢含量的定量

Nuclear reaction analysis (NRA) via the resonant 1H(15N,&#945;&#947;)12C reaction is a highly effective method of depth profiling that quantitatively and ...

Comprehensive Characterization of Extended Defects in Semiconductor Materials by a Scanning Electron Microscope

Extended defects such as dislocations and grain boundaries have a strong influence on the performance of microelectronic devices and on other applications of semiconductor materials. However, it is still under debate how the defect structure determines the band structure, and therefore, the recombination behavior of electron-hole pairs responsible for the optical and electrical properties of the extended defects. The present paper is a survey of procedures for the spatially resolved investigation of structural and of physical properties of extended defects in semiconductor materials with a scanning electron microscope (SEM). Representative examples are given for crystalline silicon. The luminescence behavior of extended defects can be investigated by cathodoluminescence (CL) measurements. They are particularly valuable because spectrally and spatially resolved information can be obtained simultaneously. For silicon, with an indirect electronic band structure, CL measurements should be carried out at low temperatures down to 5 K due to the low fraction of radiative recombination processes in comparison to non-radiative transitions at room temperature. For the study of the electrical properties of extended defects, the electron beam induced current (EBIC) technique can be applied. The EBIC image reflects the local distribution of defects due to the increased charge-carrier recombination in their vicinity. The procedure for EBIC investigations is described for measurements at room temperature and at low temperatures. Internal strain fields arising from extended defects can be determined quantitatively by cross-correlation electron backscatter diffraction (ccEBSD). This method is challenging because of the necessary preparation of the sample surface and because of the quality of the diffraction patterns which are recorded during the mapping of the sample. The spatial resolution of the three experimental techniques is compared.

The optical, electrical, and structural properties of dislocations and of grain boundaries in semiconductor materials can be determined by experiments performed in a scanning electron microscope. Electron microscopy has been used to investigate cathodoluminescence, electron beam induced current, and diffraction of backscattered electrons.

通过扫描电子显微镜在半导体材料的扩展缺陷的全面表征

Extended defects such as dislocations and grain boundaries have a strong influence on the performance of microelectronic devices and on other applications ...

Scanning SQUID Study of Vortex Manipulation by Local Contact

Local, deterministic manipulation of individual vortices in type 2 superconductors is challenging. The ability to control the position of individual vortices is necessary in order to study how vortices interact with each other, with the lattice, and with other magnetic objects. Here, we present a protocol for vortex manipulation in thin superconducting films by local contact, without applying current or magnetic field. Vortices are imaged using a scanning superconducting quantum interference device (SQUID), and vertical stress is applied to the sample by pushing the tip of a silicon chip into the sample, using a piezoelectric element. Vortices are moved by tapping the sample or sweeping it with the silicon tip. Our method allows for effective manipulation of individual vortices, without damaging the film or affecting its topography. We demonstrate how vortices were relocated to distances of up to 0.8 mm. The vortices remained stable at their new location up to five days. With this method, we can control vortices and move them to form complex configurations. This technique for vortex manipulation could also be implemented in applications such as vortex based logic devices.

We present a protocol for manipulation of individual vortices in thin superconducting films, using local mechanical contact. The method does not include applying current, magnetic field or additional fabrication steps.

由当地接触式扫描涡操纵SQUID研究

Local, deterministic manipulation of individual vortices in type 2 superconductors is challenging. The ability to control the position of individual ...

Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent

The aim of this work is to present a zero-waste process for storing CO2 in a stable and benign mineral form while producing zeolitic minerals with sufficient heavy metal adsorption capacity. To this end, blast furnace slag, a residue from iron-making, is utilized as the starting material. Calcium is selectively extracted from the slag by leaching with acetic acid (2 M CH3COOH) as the extraction agent. The filtered leachate is subsequently physico-chemically purified and then carbonated to form precipitated calcium carbonate (PCC) of high purity (&lt;2 wt% non-calcium impurities, according to ICP-MS analysis). Sodium hydroxide is added to neutralize the regenerated acetate. The morphological properties of the resulting calcitic PCC are tuned for its potential application as a filler in papermaking. In parallel, the residual solids from the extraction stage are subjected to hydrothermal conversion in a caustic solution (2 M NaOH) that leads to the predominant formation of a particular zeolitic mineral phase (detected by XRD), namely analcime (NaAlSi2O6&#8729;H2O). Based on its ability to adsorb Ni2+, as reported from batch adsorption experiments and ICP-OES analysis, this product can potentially be used in wastewater treatment or for environmental remediation applications.

A protocol for the parallel production of precipitated calcium carbonate and zeolitic material from blast furnace slag via mineral carbonation and alkaline hydrothermal conversion, respectively, is presented. The performance of the zeolitic material towards nickel adsorption is tested.

高炉矿渣的双向稳定物价:沉淀碳酸钙和沸石重金属吸附剂的合成

The aim of this work is to present a zero-waste process for storing CO2 in a stable and benign mineral form while producing zeolitic minerals with ...

Precision Milling of Carbon Nanotube Forests Using Low Pressure Scanning Electron Microscopy

A nanoscale fabrication technique appropriate for milling carbon nanotube (CNT) forests is described. The technique utilizes an environmental scanning electron microscope (ESEM) operating with a low pressure water vapor ambient. In this technique, a portion of the electron beam interacts with the water vapor in the vicinity of the CNT sample, dissociating the water molecules into hydroxyl radicals and other species by radiolysis. The remainder of the electron beam interacts with the CNT forest sample, making it susceptible to oxidation from the chemical products of radiolysis. This technique may be used to trim a selected region of an individual CNT, or it may be used to remove hundreds of cubic microns of material by adjusting ESEM parameters. The machining resolution is similar to the imaging resolution of the ESEM itself. The technique produces only small quantities of carbon residue along the boundaries of the cutting zone, with minimal effect on the native structural morphology of the CNT forest.

Low pressure scanning electron microscopy in a water vapor ambient is used to machine nanoscale to microscale features in carbon nanotube forests.

碳纳米管森林精密铣床使用低压扫描电子显微镜

A nanoscale fabrication technique appropriate for milling carbon nanotube (CNT) forests is described. The technique utilizes an environmental scanning ...

High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia (YSZ) Scaffolds by In Situ Carbon Templating Xerogels

We demonstrate a method for the high temperature fabrication of porous, nanostructured yttria-stabilized-zirconia (YSZ, 8 mol% yttria - 92 mol% zirconia) scaffolds with tunable specific surface areas up to 80 m2&#183;g-1. An aqueous solution of a zirconium salt, yttrium salt, and glucose is mixed with propylene oxide (PO) to form a gel. The gel is dried under ambient conditions to form a xerogel. The xerogel is pressed into pellets and then sintered in an argon atmosphere. During sintering, a YSZ ceramic phase forms and the organic components decompose, leaving behind amorphous carbon. The carbon formed in situ serves as a hard template, preserving a high surface area YSZ nanomorphology at sintering temperature. The carbon is subsequently removed by oxidation in air at low temperature, resulting in a porous, nanostructured YSZ scaffold. The concentration of the carbon template and the final scaffold surface area can be systematically tuned by varying the glucose concentration in the gel synthesis. The carbon template concentration was quantified using thermogravimetric analysis (TGA), the surface area and pore size distribution was determined by physical adsorption measurements, and the morphology was characterized using scanning electron microscopy (SEM). Phase purity and crystallite size was determined using X-ray diffraction (XRD). This fabrication approach provides a novel, flexible platform for realizing unprecedented scaffold surface areas and nanomorphologies for ceramic-based electrochemical energy conversion applications, e.g. solid oxide fuel cell (SOFC) electrodes.

High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia YSZ Scaffolds by In Situ Carbon Templating Xerogels

A protocol for fabricating porous, nanostructured yttria-stabilized-zirconia (YSZ) scaffolds at temperatures between 1,000 &#176;C and 1,400 &#176;C is presented.

通过纳米氧化钇稳定的二氧化锆（YSZ）的支架的高温加工<em&gt;原位</em&gt;碳模板干凝胶

We demonstrate a method for the high temperature fabrication of porous, nanostructured yttria-stabilized-zirconia (YSZ, 8 mol% yttria - 92 mol% zirconia) ...

Fabrication of 3D Carbon Microelectromechanical Systems (C-MEMS)

A wide range of carbon sources are available in nature, with a variety of micro-/nanostructure configurations. Here, a novel technique to fabricate long and hollow glassy carbon microfibers derived from human hairs is introduced. The long and hollow carbon structures were made by the pyrolysis of human hair at 900 &#176;C in a N2 atmosphere. The morphology and chemical composition of natural and pyrolyzed human hairs were investigated using scanning electron microscopy (SEM) and electron-dispersive X-ray spectroscopy (EDX), respectively, to estimate the physical and chemical changes due to pyrolysis. Raman spectroscopy was used to confirm the glassy nature of the carbon microstructures. Pyrolyzed hair carbon was introduced to modify screen-printed carbon electrodes ; the modified electrodes were then applied to the electrochemical sensing of dopamine and ascorbic acid. Sensing performance of the modified sensors was improved as compared to the unmodified sensors. To obtain the desired carbon structure design, carbon micro-/nanoelectromechanical system (C-MEMS/C-NEMS) technology was developed. The most common C-MEMS/C-NEMS fabrication process consists of two steps: (i) the patterning of a carbon-rich base material, such as a photosensitive polymer, using photolithography; and (ii) carbonization through the pyrolysis of the patterned polymer in an oxygen-free environment. The C-MEMS/NEMS process has been widely used to develop microelectronic devices for various applications, including in micro-batteries, supercapacitors, glucose sensors, gas sensors, fuel cells, and triboelectric nanogenerators. Here, recent developments of a high-aspect ratio solid and hollow carbon microstructures with SU8 photoresists are discussed. The structural shrinkage during pyrolysis was investigated using confocal microscopy and SEM. Raman spectroscopy was used to confirm the crystallinity of the structure, and the atomic percentage of the elements present in the material before and after pyrolysis was measured using EDX.

Fabrication of 3D Carbon Microelectromechanical Systems C-MEMS

Long and hollow glassy carbon microfibers were fabricated based on the pyrolysis of a natural product, human hair. The two fabrication steps of carbon microelectromechanical and carbon nanoelectromechanical systems, or C-MEMS and C-NEMS, are: (i) photolithography of a carbon-rich polymer precursor and (ii) pyrolysis of the patterned polymer precursor.

3D碳微机电系统（C-MEMS）的制造

A wide range of carbon sources are available in nature, with a variety of micro-/nanostructure configurations. Here, a novel technique to fabricate long ...

Production and Characterization of Vacuum Deposited Organic Light Emitting Diodes

A method for producing simple and efficient thermally-activated delayed fluorescence organic light-emitting diodes (OLEDs) based on guest-host or exciplex donor-acceptor emitters is presented. With a step-by-step procedure, readers will be able to repeat and produce OLED devices based on simple organic emitters. A patterning procedure allowing the creation of personalized indium tin oxide (ITO) shape is shown. This is followed by the evaporation of all layers, encapsulation and characterization of each individual device. The end goal is to present a procedure that will give the opportunity to repeat the information presented in cited publication but also using different compounds and structures in order to prepare efficient OLEDs.

A protocol for the production of simple structured organic light-emitting diodes (OLEDs) is presented.

真空沉积有机发光二极管的生产与表征

A method for producing simple and efficient thermally-activated delayed fluorescence organic light-emitting diodes (OLEDs) based on guest-host or exciplex ...