这项工作是由石油技术发展基金 (尼日利亚 PTDF) 和英国工程和自然科学研究理事会 (赠款编号 EP/K003976/1) 赞助的。作者还感谢 Zhizhao 博士的卓有成效的讨论。

1. 实验台安装
注: 见图 1。
<ol><li>
降膜单元
	<ol>
<li>首先用干净的软布清洁基板 (玻璃) 表面。确保不粘附在其表面上的污垢, 这将改变液体的性质。</li>
		<li>将玻璃基底的枢轴设置为所需倾角。在这项工作中使用了一个倾斜角, β, 15˚。</li>
		<li>打开电泵, 确保薄膜表面有正常的液体流动, 进一步清洁玻璃基体。对于这项工作, 测试液是去离子水。</li>
		<li>确保承印物的整个表面被润湿。</li>
		<li>使用流量计测量胶片流量。对于这项工作, 流量是不同的 1.667 x 10-3和 10 x 10-3 m3/秒与相应的胶片雷诺数,再 = ρq/wµ, 范围在55.5 和333之间。w是下落的影片宽度, 0.30 m。</li>
		<li>逐步调整流量连接上的阀门, 以获得所需的玻璃基板的流量。</li>
		<li>在胶片入口调整一组千分尺步骤, 以对应的努塞尔膜厚度值为所选流速, 避免在胶片进气道上进行水力跳跃或将空气回流到配电室。</li>
		<li>手动虹吸分配室中的所有空气, 以获得在薄膜表面下游的均匀流。</li>
	</ol>
</li>
	<li>
胶片控制单元
	<ol>
<li>通过数据采集卡 (DAC) 确保功能发生器通过非闭锁中继连接到电磁阀。</li>
		<li>开关电磁阀和功能发生器。</li>
		<li>将函数生成器设置为所需的强制频率。在这项工作中, 使用了2和 3 Hz 的频率。</li>
		<li>选择所需的波形信号 (正弦波、锯齿波、方波等) 。在这项工作中, 使用了正弦波信号。图 2A和2B显示了控制膜与受控薄膜的对比度。</li>
	</ol>
</li>
	<li>
液滴生成系统
	<ol>
<li>把一个干净的塑料油管连接到充水的注射器上。</li>
		<li>将注射器插入液滴发生器中。</li>
		<li>将所选尺寸的注射器针 (取决于所需的水滴直径) 粘贴到塑料管材的另一端。研究的雾滴直径范围介于0.0023 到0.0044 米之间。</li>
		<li>调整薄膜表面上方的跌落高度。在这项工作中, 下落的下落高度从0.005 到 0.45 m 是不同的, 给冲击速度在0.30 里-0.02-2.96 @ 0.06 米/s 之间。</li>
		<li>同样, 设置从胶片入口滴的流向冲击点。这在这项工作中设置为0.3 米, 以确保波浪在撞击之前形成良好的波形。</li>
		<li>设置注射器泵所需的流量。</li>
		<li>调整流量以达到比薄膜表面形成的波的波长大的雾滴产生频率;确保水滴连续撞击受控薄膜的不同区域。见图 2C;随着图 2D中奇异波形的增大, 显示出每个区域19、20下的流剖面上的不同之处在。</li>
	</ol>
</li>
	<li>
高速成像设置
	<ol>
<li>将相机放在三脚架架上 (或任何其他合适的安排)。</li>
		<li>选择需要焦距的宏透镜并将其连接到照相机。</li>
		<li>打开高速摄像机, 确保直接聚焦在胶片表面上。将相机与7˚和12˚的水平和垂直偏差分别对准胶片表面。这给出了影响过程的极好的侧面视图图像, 从而分别在流向和展方向上产生了67.5 µm/像素和46.6 µm/像素的分辨率。</li>
		<li>使用精确放置在液滴撞击点上的校准项, 调整相机透镜 (最大光圈) 的焦距。</li>
		<li>一旦获得了尖锐的焦点, 减少光圈, 以确保只有少量的光线进入相机。</li>
		<li>设置高速相机所需的帧速率、分辨率和快门速度。本工作采用帧速率为 5000 fps, 800 x 600 分辨率, 孔径 1/16, 快门速度为1µs。</li>
		<li>将光扩散器放在光源的前面, 如图 1C所示, 以确保光线在成像区域内均匀扩散。</li>
		<li>电源上的光源, 以确认均匀传播光在成像区域。</li>
	</ol>
</li>
</ol>2. 校准
注: 见图 3。
<ol><li>把尺子放在胶片的流动方向上 (正好在撞击现场), 并获得胶片表面上测量点的快照。</li>
	<li>重复 2.1, 但与统治者在展方向。</li>
	<li>使用上面的空间分辨率来获取胶片表面。</li>
</ol>3. 视频记录和数据采集
<ol><li>一旦在钻机上建立了薄膜流, 启动注射器泵并观察滴水滴对薄膜表面的影响。</li>
	<li>启动函数发生器, 观察薄膜表面 spatiotemporally 规则波的产生。</li>
	<li>确保连续水滴对受控薄膜表面的不同区域产生影响。</li>
	<li>观察触发后的帧数, 并将其设置为视频长度的大约一半, 以充分捕捉影响。</li>
	<li>电源上的光源, 并触发图像捕获一旦影响发生。</li>
	<li>一旦图像捕获完成, 就关闭光源电源, 以避免液体膜过热。</li>
	<li>在计算机屏幕上直观地分析获得的快照。检查是否在平面薄膜、毛细管波或波浪驼峰区域中发生了撞击。</li>
	<li>将视频修剪到显示影响过程的部分, 并将帧范围保存为视频/图像格式。</li>
	<li>重复 3.5-3.8, 记录个人对胶片表面上所有区域的影响, 即孤立的驼峰、毛细管波和平板薄膜。</li>
</ol>4. 图像后处理和分析
<ol><li>将标尺放在视图字段中, 计算空间分辨率, 方法是计算1厘米的像素大小. 使用标定图像, 获得图像尺寸测量的比例因子。</li>
	<li>将撞击过程的结果与高速图像的不同撞击区域进行比较。检查以看到显著的差异。</li>
	<li>采用合适的 MATLAB 图像处理程序, 测量冲击过程产品的特性特征: 即在飞溅模式下, 测量树冠高度、直径、壁厚、倾角、顶面方向、数量和尺寸喷射二次滴的分布。</li>
	<li>对低韦伯的影响进行类似的定量分析, 如4.3。从时间帧图像中计算出卫星下落的时间, 测量二次滴下的部分聚结中形成的柱的先端长度和宽度。测量被弹出的二次水滴的大小。计算重复的收缩过程中的级联数。</li>
	<li>观察每个区域的质量差异。</li>
</ol>

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作者没有什么要申报的。

在本节中, 我们提供了一些必要的提示, 以确保从协议中获得质量结果。首先, 必须保持液体膜流动的玻璃基片完全无污垢, 以确保液膜的性能保持不折不扣。这是可以实现的定期清洁 (可能使用适当的洗涤剂, 并擦过托盘, 以避免溶解进入系统)。同样地, 在试验过的几回合后, 应定期更换整个试验液, 以保证准确的结果。
其次, 流体分配室必须良好的啮合, 并保持气密, 以确保出水液膜是均匀的。这可以通过手动将空气从配电箱中抽取出来, 然后再进行实验。还建议在胶片进气口使用千分尺步骤, 将胶片入口的间隙高度设置为在相应雷诺数努塞尔估计的胶片流的精确胶片厚度。这将防止水力跳跃或回流在入口。
电磁阀的操作也必须始终进行正确的检查和确定。这是因为需要一个适当的脉动的流量, 以确保生产的强迫波。这可以从正常点击的电磁阀的声音, 以及感知脉动沿连接管道。液体流量进入注射器泵也必须小心设置, 以确保水滴被弹出的方式, 避免任何前加速度下降之前。
必须确保高速相机的适当校准, 以获得非常准确的结果。考虑到景深、曝光时间和整体图像亮度等参数, 还必须仔细选择孔径大小。对于在视频录制过程中触发的摄像头, 用户还需要估计在触发前应该记录多少帧。这可能与个人不同, 这取决于下落影响时间, 因此, 建议在实际测量之前进行几次练习试验。同样, 光源必须正确排列和扩散, 以最小化图像中的阴影。
重要的是要注意和记住, 研究的主要焦点是波浪对下落下落的冲击动力学的贡献, 因此规则波浪结构的形成是对基础物理的精确研究的必要。在观测到波浪结构迅速过渡到三维结构的情况下, 建议将基底倾角减小14,19 , 以促进波浪结构的缓慢过渡。.
在没有测量装置的情况下, 观察到在每个撞击区域的实际瞬时膜厚度时, 该技术的一个局限性。这将提供关于整个观察到的现象的更多细节。
总之, 本报告概述的程序也可以用来研究简单的波演化动力学, 而所描述的高速成像系统可以应用到许多研究领域的快速动力学, 如液滴分解21,22/聚结23, 颗粒射流24,等重要现象在微观时间刻度上观察到。

水滴撞击是自然界中非常常见的现象, 吸引了好奇的观察者1的注意。它是一个活跃的研究领域, 因为它的许多应用, 包括喷雾冷却, 防火, 喷墨打印, 喷涂, 在印制电路板上的焊点沉积, 内燃机的设计,表面清洗和细胞印刷2。它的应用也延伸到农业,例如喷洒灌溉和作物喷洒3,4。创业的工作可以追溯到 19世纪, 与沃灵顿5的工作, 而主要的进展是最近才作出的, 因为出现了高速成像6。从那时起, 进行了几项研究;使用不同类型的撞击面, 从固体7,8, 浅,9和深液池10,11到薄膜12,13。
然而, 尽管大量的研究液滴撞击液体表面 (即浅和深池和淡静膜), 对流动薄液膜的影响没有得到重视。此外, 迄今为止, 研究忽略了波浪空间结构对水滴撞击动力学的贡献。
在本报告中, 我们提出了一个详细的实验程序, 以研究液滴冲击过程的流动薄膜, 其动力学受进口强迫的液体流速;下面, 我们把它们称为 "受控" 的电影。我们发现, 这些在多相工业中有许多应用 (例如,在冷却塔, 精馏塔, 以及在两相流中观察到的环状流系统), 尤其是薄膜控制已经成为在许多过程工业中强化传热和传质14。感兴趣的读者被提到我们以前的工作15 , 更多的细节, 我们的研究成果, 在这方面。
这一应用的频率振荡的入口流量产生的规则波在薄膜表面的形成。我们专注于孤立波家庭, 它的特点是广泛分离的窄峰, 前面是一系列前运行的毛细管波16,17,18。我们研究了与孤波结构的三主要部分有关的影响的结果: "平板薄膜"、"波浪驼峰" 和前运行的 "毛细管波" 区域。我们还将这些结果与不受控制的流动薄膜相比较。结果表明, 在不受控薄膜上的波出现的随机性质明显地影响了水滴撞击的结果, 而控制膜的分离区域也显示出新的机制, 我们在定性和定量。
在前15篇论文中, 采用相同的程序, 研究了膜控制对溅淋体系中液滴冲击动力学的影响。所得结果表明, 在冠层形态 (高度、直径、壁厚、倾角和方向) 上的数量和质量差异, 以及喷射二次滴的数量和大小分布。
在本报告中, 我们描述了设计的设置, 以了解这些空间结构在液滴撞击动力学中所起的关键作用, 同时也提供了我们的研究结果的简明细节, 不仅在飞溅的机制, 也为其他结果的水滴冲击 (即弹跳, 滑动, 部分/总接合)。按照下面描述的标准协议, 薄膜控制对液滴撞击动力学的影响可以以可重现的方式进行研究。

<table>
	<tbody>
		<tr>
			<td>Function generator</td>
			<td>GW INSTEK</td>
			<td>AFG 2005 Series, Digital. Geo0852266</td>
			<td>Produces a varied type of wave signals, ranging from sine, square to saw-tooth wave at different frequencies (0.1 Hz - 5 MHz).</td>
		</tr>
		<tr>
			<td>Syringe pump</td>
			<td>Braintree Scientific Inc.</td>
			<td>Bs-8000 /225540</td>
			<td></td>
		</tr>
		<tr>
			<td>Solenoid valve</td>
			<td>SMC-VXD</td>
			<td>2142A. 
			0AE-5001</td>
			<td>Series-pilot-operated-two-port</td>
		</tr>
		<tr>
			<td>Relay</td>
			<td>Takamisara</td>
			<td>A5W-K. 
			154424C-03L</td>
			<td></td>
		</tr>
		<tr>
			<td>Electric pump</td>
			<td>Clarke SP</td>
			<td>SPE1200SS 1</td>
			<td></td>
		</tr>
		<tr>
			<td>Flow meter</td>
			<td>RS Component</td>
			<td>CYNERGY3 UF25B 14011600040110</td>
			<td>Measurement range: 0.2-25 L/min</td>
		</tr>
		<tr>
			<td>Micrometer step</td>
			<td>RS Component</td>
			<td>Micrometer Head</td>
			<td>0.01 mm/0 -13 mm</td>
		</tr>
		<tr>
			<td>High-speed camera</td>
			<td>Olympus</td>
			<td>I-SPEED 3.</td>
			<td>Capable of recording at up to 100, 000 frames per second.</td>
		</tr>
		<tr>
			<td>Light source</td>
			<td>TLC Electrical supplies</td>
			<td>IP54 -black</td>
			<td>Double enclosed halogen floodlight. Rating 500 W.</td>
		</tr>
		<tr>
			<td>Light diffusor</td>
			<td>OptiGraphix</td>
			<td>DFPMET</td>
			<td>250 &#956;m thickness</td>
		</tr>
		<tr>
			<td>Glass substrate</td>
			<td>Instrument Glasses Ltd</td>
			<td>Soda Lime Float Glass; 570 mm x 300 mm x 4 mm</td>
			<td>Flatness tolerance 0.02/0.04.</td>
		</tr>
		<tr>
			<td>Macro-lenses</td>
			<td>(a) Nikon 
			(b) Sigma</td>
			<td>(a) AF-Micro-Nikkor 60 mm f/2.8 D 
			(b) 105 mm f/2.8 Macro-Ex</td>
			<td></td>
		</tr>
		<tr>
			<td>Test-liquid</td>
			<td>De-ionized water from the Imperial College Analytical Lab.</td>
			<td>Standard solution 
			(AnalaR)</td>
			<td></td>
		</tr>
	</tbody>
</table>

film control to study contributions of waves to droplet impact dynamics on thin flowing liquid films

水滴撞击是自然界中常见的一种现象, 由于其审美魅力和广泛应用, 引起了人们的关注。以往对流动液体薄膜的研究忽略了波浪空间结构对撞击结果的贡献, 而这最近被证明对水滴撞击动力学有很大的影响。在本报告中, 我们概述了一步一步的过程, 以研究一个流动的液体膜周期性进口强迫的影响, 导致生产 spatiotemporally 规则波结构的下降冲击动力学。一个与电磁阀连接的函数发生器用来激发这些 spatiotemporally 的规则波结构在薄膜表面, 而均匀大小的水滴的撞击动力学使用高速相机捕获。然后研究了三个不同的区域;即峰、扁膜区和波浪驼峰区前的毛细管波区。研究了膜雷诺、降韦伯和 Ohnesorge 数等重要无量纲量对膜流速、降速度和降径参数的影响。我们的结果显示了有趣的, 迄今未被发现的动态, 这一应用的电影进口强迫的流动薄膜的低和高惯性下降。

Watch this Scientific Journal Video about Film Control to Study Contributions of Waves to Droplet Impact Dynamics on Thin Flowing Liquid Films at JoVE.com

Film Control to Study Contributions of Waves to Droplet Impact Dynamics on Thin Flowing Liquid Films

本文提出了一种研究波浪对液滴撞击动力学的影响的协议。

薄膜控制研究波浪对液滴冲击动力学的影响薄流动液体薄膜

Droplet impact is a very common phenomenon in nature and attracts attention due to its aesthetic fascination and wide-ranging applications. Previous ...

film-control-to-study-contributions-waves-to-droplet-impact-dynamics

Research

JoVE Journal

Engineering

7.3K 次观看.  Imperial College London. 本文提出了一种研究波浪对液滴撞击动力学的影响的协议。

视频: Film Control to Study Contributions of Waves to Droplet Impact Dynamics on Thin Flowing Liquid Films

Polycrystalline Silicon Thin-film Solar cells with Plasmonic-enhanced Light-trapping

One of major approaches to cheaper solar cells is reducing the amount of semiconductor material used for their fabrication and making cells thinner. To compensate for lower light absorption such physically thin devices have to incorporate light-trapping which increases their optical thickness. Light scattering by textured surfaces is a common technique but it cannot be universally applied to all solar cell technologies. Some cells, for example those made of evaporated silicon, are planar as produced and they require an alternative light-trapping means suitable for planar devices. Metal nanoparticles formed on planar silicon cell surface and capable of light scattering due to surface plasmon resonance is an effective approach.
The paper presents a fabrication procedure of evaporated polycrystalline silicon solar cells with plasmonic light-trapping and demonstrates how the cell quantum efficiency improves due to presence of metal nanoparticles.
To fabricate the cells a film consisting of alternative boron and phosphorous doped silicon layers is deposited on glass substrate by electron beam evaporation. An Initially amorphous film is crystallised and electronic defects are mitigated by annealing and hydrogen passivation. Metal grid contacts are applied to the layers of opposite polarity to extract electricity generated by the cell. Typically, such a ~2 &mu;m thick cell has a short-circuit current density (Jsc) of 14-16 mA/cm2, which can be increased up to 17-18 mA/cm2 (~25% higher) after application of a simple diffuse back reflector made of a white paint.
To implement plasmonic light-trapping a silver nanoparticle array is formed on the metallised cell silicon surface. A precursor silver film is deposited on the cell by thermal evaporation and annealed at 23&deg;C to form silver nanoparticles. Nanoparticle size and coverage, which affect plasmonic light-scattering, can be tuned for enhanced cell performance by varying the precursor film thickness and its annealing conditions. An optimised nanoparticle array alone results in cell Jsc enhancement of about 28%, similar to the effect of the diffuse reflector. The photocurrent can be further increased by coating the nanoparticles by a low refractive index dielectric, like MgF2, and applying the diffused reflector. The complete plasmonic cell structure comprises the polycrystalline silicon film, a silver nanoparticle array, a layer of MgF2, and a diffuse reflector. The Jsc for such cell is 21-23 mA/cm2, up to 45% higher than Jsc of the original cell without light-trapping or ~25% higher than Jsc for the cell with the diffuse reflector only.
Introduction
Light-trapping in silicon solar cells is commonly achieved via light scattering at textured interfaces. Scattered light travels through a cell at oblique angles for a longer distance and when such angles exceed the critical angle at the cell interfaces the light is permanently trapped in the cell by total internal reflection (Animation 1: Light-trapping). Although this scheme works well for most solar cells, there are developing technologies where ultra-thin Si layers are produced planar (e.g. layer-transfer technologies and epitaxial c-Si layers) 1 and or when such layers are not compatible with textures substrates (e.g. evaporated silicon) 2. For such originally planar Si layer alternative light trapping approaches, such as diffuse white paint reflector 3, silicon plasma texturing 4 or high refractive index nanoparticle reflector 5 have been suggested.
Metal nanoparticles can effectively scatter incident light into a higher refractive index material, like silicon, due to the surface plasmon resonance effect 6. They also can be easily formed on the planar silicon cell surface thus offering a light-trapping approach alternative to texturing. For a nanoparticle located at the air-silicon interface the scattered light fraction coupled into silicon exceeds 95% and a large faction of that light is scattered at angles above critical providing nearly ideal light-trapping condition (Animation 2: Plasmons on NP). The resonance can be tuned to the wavelength region, which is most important for a particular cell material and design, by varying the nanoparticle average size, surface coverage and local dielectric environment 6,7. Theoretical design principles of plasmonic nanoparticle solar cells have been suggested 8. In practice, Ag nanoparticle array is an ideal light-trapping partner for poly-Si thin-film solar cells because most of these design principle are naturally met. The simplest way of forming nanoparticles by thermal annealing of a thin precursor Ag film results in a random array with a relatively wide size and shape distribution, which is particularly suitable for light-trapping because such an array has a wide resonance peak, covering the wavelength range of 700-900 nm, important for poly-Si solar cell performance. The nanoparticle array can only be located on the rear poly-Si cell surface thus avoiding destructive interference between incident and scattered light which occurs for front-located nanoparticles 9. Moreover, poly-Si thin-film cells do not requires a passivating layer and the flat base-shaped nanoparticles (that naturally result from thermal annealing of a metal film) can be directly placed on silicon further increases plasmonic scattering efficiency due to surface plasmon-polariton resonance 10.
The cell with the plasmonic nanoparticle array as described above can have a photocurrent about 28% higher than the original cell. However, the array still transmits a significant amount of light which escapes through the rear of the cell and does not contribute into the current. This loss can be mitigated by adding a rear reflector to allow catching transmitted light and re-directing it back to the cell. Providing sufficient distance between the reflector and the nanoparticles (a few hundred nanometers) the reflected light will then experience one more plasmonic scattering event while passing through the nanoparticle array on re-entering the cell and the reflector itself can be made diffuse - both effects further facilitating light scattering and hence light-trapping. Importantly, the Ag nanoparticles have to be encapsulated with an inert and low refractive index dielectric, like MgF2 or SiO2, from the rear reflector to avoid mechanical and chemical damage 7. Low refractive index for this cladding layer is required to maintain a high coupling fraction into silicon and larger scattering angles, which are ensured by the high optical contrast between the media on both sides of the nanoparticle, silicon and dielectric 6. The photocurrent of the plasmonic cell with the diffuse rear reflector can be up to 45% higher than the current of the original cell or up to 25% higher than the current of an equivalent cell with the diffuse reflector only.

Polycrystalline silicon thin-film solar cells on glass are fabricated by deposition of boron and phosphorous doped silicon layers followed by crystallisation, defect passivation and metallisation. Plasmonic light-trapping is introduced by forming Ag nanoparticles on the silicon cell surface capped with a diffused reflector resulting in ~45% photocurrent enhancement.

多晶硅薄膜太阳能电池电浆增强光捕获

One of major approaches to cheaper solar cells is reducing the amount of semiconductor material used for their fabrication and making cells thinner. To ...

科研

工程学

Nanomoulding of Functional Materials, a Versatile Complementary Pattern Replication Method to Nanoimprinting

We describe a nanomoulding technique which allows low-cost nanoscale patterning of functional materials, materials stacks and full devices. Nanomoulding combined with layer transfer enables the replication of arbitrary surface patterns from a master structure onto the functional material. Nanomoulding can be performed on any nanoimprinting setup and can be applied to a wide range of materials and deposition processes. In particular we demonstrate the fabrication of patterned transparent zinc oxide electrodes for light trapping applications in solar cells.

We describe a nanomoulding technique which allows low-cost nanoscale patterning of functional materials, materials stacks and full devices. Nanomoulding can be performed on any nanoimprinting setup and can be applied to a wide range of materials and deposition processes.

Nanomoulding功能材料，灵活的互补模式的复制方法，以奈米

We describe a nanomoulding technique which  allows low-cost nanoscale patterning of functional materials, materials stacks  and full devices. Nanomoulding ...

Fast Imaging Technique to Study Drop Impact Dynamics of Non-Newtonian Fluids

In the field of fluid mechanics, many dynamical processes not only occur over a very short time interval but also require high spatial resolution for detailed observation, scenarios that make it challenging to observe with conventional imaging systems. One of these is the drop impact of liquids, which usually happens within one tenth of millisecond. To tackle this challenge, a fast imaging technique is introduced that combines a high-speed camera (capable of up to one million frames per second) with a macro lens with long working distance to bring the spatial resolution of the image down to 10 &#181;m/pixel. The imaging technique enables precise measurement of relevant fluid dynamic quantities, such as the flow field, the spreading distance and the splashing speed, from analysis of the recorded video. To demonstrate the capabilities of this visualization system, the impact dynamics when droplets of non-Newtonian fluids impinge on a flat hard surface are characterized. Two situations are considered: for oxidized liquid metal droplets we focus on the spreading behavior, and for densely packed suspensions we determine the onset of splashing. More generally, the combination of high temporal and spatial imaging resolution introduced here offers advantages for studying fast dynamics across a wide range of microscale phenomena.

Drop impact of non-Newtonian fluids is a complex process since different physical parameters influence the dynamics over a very short time (less than one tenth of a millisecond). A fast imaging technique is introduced in order to characterize the impact behaviors of different non-Newtonian fluids.

快速成像技术来研究非牛顿流体的跌落冲击动力学

In the field of fluid mechanics, many dynamical processes not only occur over a very short time interval but also require high spatial resolution for ...

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 ...

Recombination Dynamics in Thin-film Photovoltaic Materials via Time-resolved Microwave Conductivity

A method for investigating recombination dynamics of photo-induced charge carriers in thin film semiconductors, specifically in photovoltaic materials such as organo-lead halide perovskites is presented. The perovskite film thickness and absorption coefficient are initially characterized by profilometry and UV-VIS absorption spectroscopy. Calibration of both laser power and cavity sensitivity is described in detail. A protocol for performing Flash-photolysis Time Resolved Microwave Conductivity (TRMC) experiments, a non-contact method of determining the conductivity of a material, is presented. A process for identifying the real and imaginary components of the complex conductivity by performing TRMC as a function of microwave frequency is given. Charge carrier dynamics are determined under different excitation regimes (including both power and wavelength). Techniques for distinguishing between direct and trap-mediated decay processes are presented and discussed. Results are modelled and interpreted with reference to a general kinetic model of photoinduced charge carriers in a semiconductor. The techniques described are applicable to a wide range of optoelectronic materials, including organic and inorganic photovoltaic materials, nanoparticles, and conducting/semiconducting thin films.

A Time Resolved Microwave Conductivity technique for investigating direct and trap-mediated recombination dynamics and determining carrier mobilities of thin film semiconductors is presented here.

通过时间分辨微波电导率重组动力学薄膜光伏材料

A method for investigating recombination dynamics of photo-induced charge carriers in thin film semiconductors, specifically in photovoltaic materials ...

In Situ Monitoring of the Accelerated Performance Degradation of Solar Cells and Modules: A Case Study for Cu(In,Ga)Se2 Solar Cells

The levelized cost of electricity (LCOE) of photovoltaic (PV) systems is determined by, among other factors, the PV module reliability. Better prediction of degradation mechanisms and prevention of module field failure can consequently decrease investment risks as well as increase the electricity yield. An improved knowledge level can for these reasons significantly decrease the total costs of PV electricity. 
In order to better understand and minimize the degradation of PV modules, the occurring degradation mechanisms and conditions should be identified. This should preferably happen under combined stresses, since modules in the field are also simultaneously exposed to multiple stress factors. Therefore, two 'Combined Stress test with in situ measurement' setups have been designed and constructed. These setups allow the simultaneous use of humidity, temperature, illumination, and electrical biases as independently controlled stress factors on solar cells and minimodules. The setups also allow real-time monitoring of the electrical properties of these samples. This protocol presents these setups and describes the experimental possibilities. Moreover, results obtained with these setups are also presented: various examples about the influence of both deposition and degradation conditions on the stability of thin film Cu(In,Ga)Se2 (CIGS) as well as Cu2ZnSnSe4 (CZTS) solar cells are described. Results on the temperature dependency of CIGS solar cells are also presented.

In Situ Monitoring of the Accelerated Performance Degradation of Solar Cells and Modules: A Case Study for CuIn,GaSe2 Solar Cells

Two &#39;Combined Stress test with in situ measurement&#39; setups, which allow real-time monitoring of accelerated degradation of solar cells and modules, were designed and constructed. These setups allow the simultaneous use of humidity, temperature, electrical biases, and illumination as independently controlled stress factors. The setups and various experiments executed are presented.

就地太阳能电池和模块加速性能退化的监测: 铜 (in, Ga) Se2太阳能电池的实例研究

The levelized cost of electricity (LCOE) of photovoltaic (PV) systems is determined by, among other factors, the PV module reliability. Better prediction ...

Fabrication of Ultra-thin Color Films with Highly Absorbing Media Using Oblique Angle Deposition

Ultra-thin film structures have been studied extensively for use as optical coatings, but performance and fabrication challenges remain.&#160; We present an advanced method for fabricating ultra-thin color films with improved characteristics. The proposed process addresses several fabrication issues, including large area processing. Specifically, the protocol describes a process for fabricating ultra-thin color films using an electron beam evaporator for oblique angle deposition of germanium (Ge) and gold (Au) on silicon (Si) substrates.&#160; Film porosity produced by the oblique angle deposition induces color changes in the ultra-thin film. The degree of color change depends on factors such as deposition angle and film thickness. Fabricated samples of the ultra-thin color films showed improved color tunability and color purity. In addition, the measured reflectance of the fabricated samples was converted into chromatic values and analyzed in terms of color. Our ultra-thin film fabricating method is expected to be used for various ultra-thin film applications such as flexible color electrodes, thin film solar cells, and optical filters. Also, the process developed here for analyzing the color of the fabricated samples is broadly useful for studying various color structures.

We present a detailed method for fabricating ultra-thin color films with improved characteristics for optical coatings. The oblique angle deposition technique using an electron beam evaporator allows improved color tunability and purity. Fabricated films of Ge and Au on Si substrates were analyzed by reflectance measurements and color information conversion.

用斜角沉积法制备高吸收介质的超薄彩色薄膜

Ultra-thin film structures have been studied extensively for use as optical coatings, but performance and fabrication challenges remain.&#160; We present ...

Bulk and Thin Film Synthesis of Compositionally Variant Entropy-stabilized Oxides

Here, we present a procedure for the synthesis of bulk and thin film multicomponent (Mg0.25(1-x)CoxNi0.25(1-x)Cu0.25(1-x)Zn0.25(1-x))O (Co variant) and (Mg0.25(1-x)Co0.25(1-x)Ni0.25(1-x)CuxZn0.25(1-x))O (Cu variant) entropy-stabilized oxides. Phase pure and chemically homogeneous (Mg0.25(1-x)CoxNi0.25(1-x)Cu0.25(1-x)Zn0.25(1-x))O (x = 0.20, 0.27, 0.33) and (Mg0.25(1-x)Co0.25(1-x)Ni0.25(1-x)CuxZn0.25(1-x))O (x = 0.11, 0.27) ceramic pellets are synthesized and used in the deposition of ultra-high quality, phase pure, single crystalline thin films of the target stoichiometry. A detailed methodology for the deposition of smooth, chemically homogeneous, entropy-stabilized oxide thin films by pulsed laser deposition on (001)-oriented MgO substrates is described. The phase and crystallinity of bulk and thin film materials are confirmed using X-ray diffraction. Composition and chemical homogeneity are confirmed by X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy. The surface topography of thin films is measured with scanning probe microscopy. The synthesis of high quality, single crystalline, entropy-stabilized oxide thin films enables the study of interface, size, strain, and disorder effects on the properties in this new class of highly disordered oxide materials.

The synthesis of high quality bulk and thin film (Mg0.25(1-x)CoxNi0.25(1-x)Cu0.25(1-x)Zn0.25(1-x))O and (Mg0.25(1-x)Co0.25(1-x)Ni0.25(1-x)CuxZn0.25(1-x))O entropy-stabilized oxides is presented.

组分变熵稳定氧化物的体积和薄膜合成

Here, we present a procedure for the synthesis of bulk and thin film multicomponent (Mg0.25(1-x)CoxNi0.25(1-x)Cu0.25(1-x)Zn0.25(1-x))O (Co variant) and ...

Radio Frequency Magnetron Sputtering of GdBa2Cu3O7&#8722;&#948;/ La0.67Sr0.33MnO3 Quasi-bilayer Films on SrTiO3 (STO) Single-crystal Substrates

Here, we demonstrate a method of coating ferromagnetic La0.67Sr0.33MnO3 (LSMO) nanoparticles on (001) SrTiO3 (STO) single-crystal substrates by radio frequency (RF) magnetron sputtering. LSMO nanoparticles were deposited with diameters from 10 to 20 nm and heights between 20 and 50 nm. At the same time, (Gd) Ba2Cu3O7&#8722;&#948; ((Gd) BCO) films were fabricated on both undecorated and LSMO nanoparticle decorated STO substrates using RF magnetron sputtering. This report also describes the properties of GdBa2Cu3O7&#8722;&#948;/ La0.67Sr0.33MnO3 quasi-bilayer films structures (e.g., crystalline phase, morphology, chemical composition); magnetization, magneto-transport, and superconducting transport properties were also evaluated.

Radio Frequency Magnetron Sputtering of GdBa2Cu3O7ÃƒÆ’Ã‚Â¢Ãƒâ€¹Ã¢â‚¬Â 'ÃƒÆ’Ã…Â½ Â´/ La0.67Sr0.33MnO3 Quasi-bilayer Films on SrTiO3 STO Single-crystal Substrates

Here, we present a protocol to grow LSMO nanoparticles and (Gd) BCO films on (001) SrTiO3 (STO) single-crystal substrates by radio frequency (RF)-sputtering.

Gdba2cu 3 o7 的射频磁控管散射-/la0.67sr 0.67 mno 3 准双层薄膜上的 srtio 3 (sto) 单晶基板上

Here, we demonstrate a method of coating ferromagnetic La0.67Sr0.33MnO3 (LSMO) nanoparticles on (001) SrTiO3 (STO) single-crystal substrates by radio ...

Determining Tribocorrosion Rate and Wear-Corrosion Synergy of Bulk and Thin Film Aluminum Alloys

The increasing complexity and severity of service conditions in areas, such as aerospace and marine industries, nuclear systems, microelectronics, batteries, and biomedical devices, etc., impose great challenges on the reliable performance of alloys exposed to extreme conditions where mechanical and electrochemical attack co-exist. Finding ways for alloys to mitigate the combined attack of wear and corrosion (i.e., tribocorrosion) under such extreme conditions is thus highly critical for improving their reliability and service lifetime when used in such conditions. The challenge lies in the fact that wear and corrosion are not independent of each other, but rather work synergistically to accelerate the total material loss. Thus, a reliable method to evaluate the tribocorrosion resistance of metals and alloys is needed. Here, a protocol for measuring the tribocorrosion rate and wear-corrosion synergy of Al-based bulk and thin film samples in a corrosive environment under room temperature is presented.

Here, we present a protocol to measure the tribocorrosion rate and wear-corrosion synergy of thin film and bulk Al alloys in simulated sea water at room temperature.

薄膜控制研究波浪对液滴冲击动力学的影响薄流动液体薄膜

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