Os autores graças a pesquisa nacional de tecnologia de chave e o programa de desenvolvimento do Ministério da ciência e tecnologia da China (n. º 2011BAK15B06) pelo seu apoio. Agradece o Shuya Zhuang que é um estudante de mestre do nosso laboratório por nos ajudar a completar a gravação do vídeo.

1. observação da estrutura de superfície na perna de Strider da água
<ol><li>Colete água striders de lagoas de água doce locais, usando a rede de aterragem de pesca.</li>
	<li>Corte pelo menos 5 pares de pernas meio como amostras experimentais, usando a tesoura. Toque a parte inferior das pernas com cuidado, para evitar a contaminação de superfície e o desintegrador de microestrutura na frente de pernas.</li>
	<li>Seca as pernas no ar, naturalmente.</li>
	<li>Observe a microestrutura superficial das pernas usando um microscópio eletrônico de varredura com resolução de nível micro, como mostrado na Figura 1um.</li>
	<li>Observe o microsetae das pernas usando um microscópio de elétrico com nano-níveis de resolução, conforme mostrado naFigura 1b.</li>
</ol>2. prepare o componente do sistema de medição de força dinâmica
<ol><li>Comprar um sensor de filme PVDF com uma dimensão de 14,9 X 10,2 mm2 X 28 μm, que produz mais de 10 mV por microtensão. Nota: O sensor de película PVDF é usado para sentir a força de contacto dinâmica com alta sensibilidade.</li>
	<li>Comprar um amplificador de carga com ganho de carga máximo 1000 mV/pC e baixo ruído inferior a 5 μV. Nota: O amplificador de carga é utilizado para ampliar o sinal do sensor de película de PVDF, em que a saída de carga do transdutor é convertida para uma tensão.</li>
	<li>Compra um dispositivo de aquisição de dados, em que a entrada analógica tem as taxas de amostra em um intervalo de 1 s/s 102.4 kS/s. Nota: O dispositivo de aquisição de dados é usado para ler os dados de tensão do amplificador de carga e enviá-los para o computador para processamento adicional e exibir.</li>
	<li>Compra de vários estágios de alta precisão de deslocamento e um servomotor. Nota: As pernas partem de água em diferente velocidade impulsionada por servomotor.</li>
	<li>Compra uma câmera CCD, cujo comprimento de foco é em um intervalo de 5 mm a 30 mm e taxa de quadros é 30 fps. Nota: Esta câmera é usada para gravar e monitorar a deformação da superfície da água e a distância entre as pernas e a superfície da água.</li>
	<li>Prepare um computador de alto desempenho.</li>
</ol>3. montagem de todas as partes do sistema de medição de força dinâmica
<ol><li>Monte o sistema de medição de força dinâmica, de acordo com a ilustração esquemática mostrada na Figura 2uma e o instrumento de experiência real mostrado na Figura 2b.</li>
	<li>Consertar um dos lados do sensor de película de PVDF com os eléctrodos para a fase de deslocamento de alta precisão, que é colocado no quadro horizontal, como o outro lado está pendurado. Este método de instalação do sensor de película PVDF ajuda a melhorar a resolução da medição para a força dinâmica do micro.</li>
	<li>Conecte o sensor de película PVDF com o amplificador de carga, o amplificador de carga para o dispositivo de aquisição de dados e o dispositivo de aquisição de dados para o computador.</li>
	<li>Conserte a câmera para a fase de alta precisão de deslocamento, que é colocada no lado esquerdo do sensor de película PVDF.</li>
	<li>Para aproximadamente ajustar a distância entre as pernas e a água rapidamente, arrumar um estágio de alta precisão de deslocamento para o quadro acima o sensor de película PVDF, cuja separação do sensor de película de PVDF é cerca de 10 cm.</li>
	<li>Para levantar a perna longe da superfície da água a uma velocidade precisa, conserte o servomotor abaixo do palco de alta precisão de deslocamento.</li>
</ol>4. calibração do sistema de medição de força dinâmica
<ol><li>Usar o sistema de força eletrostática26 para gerar uma força constante de micro atuou na extremidade livre do sensor de película PVDF, cuja magnitude deve ser menos de 0.5 µN. controlar a força eletrostática do sistema por uma tensão aplicada aos eletrodos internos e exteriores do capacitor cilíndrico igualado. Atenção: A força deve agir em uma direção normal à superfície de película PVDF e o ponto de aplicação é suposto para ser tão próximo quanto possível para a ponta do sensor de película de PVDF para aumentar a sensibilidade.</li>
	<li>Liberte a força em um tempo curto para gerar uma entrada de passo.</li>
	<li>Ler o sinal de tensão-tempo da etapa 4.2 no computador utilizando o software LabVIEW, que ajuda ler os sinais de tensão de saída do sensor de película de PVDF.<ol>
<li>Baixe o software LabVIEW e o driver de hardware NI-DAQmx no site oficial da National Instruments.</li>
		<li>Abra o demo da medição contínua tensão analógica usando o LabVIEW, como mostra a Figura 3.</li>
		<li>Selecione o canal físico do dispositivo de aquisição de dados conectados com o amplificador de carga no módulo de Configurações de canal.</li>
		<li>Defina a taxa de amostra de 100000 e o número de amostras a 100000 no módulo de Configurações de temporização.</li>
		<li>Selecione o Log e leitura como o modo de log e escrever o caminho do arquivo para armazenar os dados de tensão no módulo de Configurações de log.</li>
		<li>Não selecione nenhum gatilho no módulo de Configurações de gatilho.</li>
		<li>Clique no botão de seta-forma na barra de ferramentas para o sinal de tensão da amostra.</li>
	</ol>
</li>
	<li>Analise a curva de tensão, em que o pico de tensão é correspondente para forçar agiu no sensor.</li>
	<li>Repita as etapas de 4,1-4,4 na entrada de força diferentes, em que uma série de pontos de tensão-força são ganhadas.</li>
	<li>Determine a relação sobre o pico de tensão de saída e o padrão força no resultado da calibração.</li>
</ol>5. medição de força de adesão a uma certa velocidade
<ol><li>Coloque uma gota de água (5 µ l) na extremidade livre do sensor de película de PVDF usando uma micropipeta mecânica. Nota: A localização da gota deve ser próximo a ponta do sensor de película de PVDF.</li>
	<li>Enfiar uma perna única para o servomotor abaixo do palco de alta precisão de deslocamento.</li>
	<li>Mova o estágio de alta precisão de deslocamento para baixo até os contatos de perna com a superfície da água, como mostrado na Figura 4um. Monitore a distância entre a superfície de perna e água por sistema de câmera montada no lado esquerdo do sensor.</li>
	<li>Levante a perna afastada da superfície da água a uma velocidade constante através do servo motor.</li>
	<li>Calcular a força correspondente a cada ponto da curva de tensão do processo de partida, com o modelo estabelecido na etapa 4.6 e em seguida, desenhe a curva força-tempo de partida do processo, conforme mostrado na Figura 4b.</li>
	<li>Recorde a adesão de pico do processo de partida a uma certa velocidade.</li>
</ol>6. medição de força de aderência em velocidades diferentes.
<ol><li>Alterar a velocidade de levantamento das pernas por servomotor e medir a força de adesão de acordo com a etapa 5.</li>
	<li>Traça a força de adesão contra o levantamento de curva de velocidade usando os dados que obteve na etapa 6.1.</li>
	<li>Analise a relação entre a força de adesão e a velocidade de levantamento através da curva.</li>
</ol>

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O autor não tem nada para divulgar.

Neste protocolo, um sistema de medição de força dinâmica baseado no sensor de película de PVDF foi com êxito concebeu, montado, calibrado para medir a força de adesão longe da superfície da água. Entre as etapas de toda, que era crucial que a força de adesão foi medida em diferentes velocidades, levantando a perna da superfície da água, como este estudo centrou-se a característica marcante de manobras rápidas sobre a água. Os resultados de partida a experiência mostraram que a força de adesão diminuiu...

Na natureza, água striders possui notável capacidade de saltar ou deslizam facilmente e rapidamente sobre a superfície da água com a ajuda das pernas delgadas e nonwetting1,2,3,4,5, mas raramente se movem lentamente, que é ao contrário os insetos terrestres. A estrutura hierárquica de água strider estabiliza o estado de superhydrophobic, que processa a dramática redução no esforço de aderência e área de contacto entre a água e a perna6,7,8, 9. no entanto, as vantagens hidrodinâmicas da retirada rápida de striders da água da superfície da água permanecem mal interpretado10,11,12.
O processo de saltar da superfície da água principalmente é dividido em três etapas13,14,15,16. Em primeiro lugar, água striders empurre para baixo a superfície da água com as pernas meio e traseiras para converter a energia biológica para a energia de superfície da água até afundar até a profundidade máxima, que permitem que o inseto inicializar a direção pula e determinar a velocidade de desmontar. Seguido pela fase ascendente, o inseto é empurrado para cima pela força capilar a curva da superfície da água até atingir a velocidade máxima. Na fase final de retirada, o strider da água continua a levantar-se pela inércia até quebrar longe da superfície da água, mas a velocidade é reduzida em grande parte devido a força de adesão com a água, que tem a principal influência sobre o consumo de energia da strider da água. Este protocolo propõe-se, portanto, para medir a força de adesão a diferentes velocidades de decolagem na fase de retirada e explicar a característica distinta de mover-se rápido.
Tem havido muitos estudos para explorar a força de adesão da água striders quando propelindo da superfície da água. Lee & Kim teoricamente e experimentalmente confirmou que a força de adesão e a energia necessária elevação pernas do strider água diminuiu drasticamente quando o ângulo de contacto aumentada para 160 graus17. Pan Jen Wei projetado um experimento de hidrostático para medir a força de adesão pelo sistema TriboScope, que foi encontrado para ser 1/5 do seu peso, 18. Kehchih Hwang analisou o processo quase estático das pernas desanexação da água com um modelo 2D e encontrei que o superhydrophobicity das pernas desempenhou um papel significativo na redução da adesão força e energia dissipação19. No entanto, a medição da força de adesão em estudos anteriores foi apenas na condição de um processo quase estático, que foi incapaz de monitorar as mudanças de força de adesão durante o salto rápido.
Neste estudo, nós projetamos um sistema de medição de força dinâmica usando polivinilideno fluoreto (PVDF) filme sensor e outro instrumento adjuvante. Comparado com outros materiais piezoelétricos, PVDF é mais apropriado para medir o microforce dinâmico com maior sensibilidade20,21,22. Integrando o sensor de película PVDF no sistema, a força de adesão em tempo real pode ser detectada e processada quando a perna estava puxando para cima de água de superfície23,24,25.

<table border="0" cellpadding="0" cellspacing="0" style="width:559px;" width="559">
	<tbody>
		<tr height="32">
			<td height="32" style="height:32px;width:87px;">PVDF film sensor</td>
			<td style="width:111px;">TE Connectivity</td>
			<td style="width:87px;">DT1-028K/L</td>
			<td style="width:275px;">The PVDF film sensor is used to sense the dynamic contact force .</td>
		</tr>
		<tr height="48">
			<td height="48" style="height:48px;width:87px;">Charge amplifier</td>
			<td style="width:111px;">Wuxi Shiao Technology co.,Ltd</td>
			<td style="width:87px;">YE5852B</td>
			<td style="width:275px;">The charge amplifier&#160;is an electronic current integrator that produces a voltage output proportional to the integrated value of the input</td>
		</tr>
		<tr height="48">
			<td height="48" style="height:48px;width:87px;">Data acquisition device</td>
			<td style="width:111px;">National Instruments</td>
			<td style="width:87px;">USB-4431</td>
			<td style="width:275px;">The data acquisition device is used to read the voltage data.</td>
		</tr>
		<tr height="48">
			<td height="48" style="height:48px;width:87px;">Displacement stage</td>
			<td style="width:111px;">ZOLIXINSTRUMENTS CO.LTD</td>
			<td style="width:87px;">KSAV1010-ZF</td>
			<td style="width:275px;">KSAV1010/2030-ZF is a wedge vertical stage with high-resolution, high-stability and high-load.</td>
		</tr>
		<tr height="48">
			<td height="48" style="height:48px;width:87px;">CCD camera</td>
			<td style="width:111px;">Shenzhen Andonstar Tech Co., Ltd</td>
			<td style="width:87px;">digital microscope A1</td>
			<td style="width:275px;">Frame rate: 30 frames/sec;Focal distance: 5mm - 30mm</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:87px;">Computer</td>
			<td style="width:111px;">Lenovo</td>
			<td style="width:87px;">G480</td>
			<td style="width:275px;"></td>
		</tr>
		<tr height="32">
			<td height="32" style="height:33px;width:87px;">Servomotor</td>
			<td style="width:111px;">EMAX US Inc.</td>
			<td style="width:87px;">ES08MD</td>
			<td style="width:275px;">It&#39;s not bad this servo with speed varying from 0.10 sec/60&#176; / 4.8v to 0.08 sec/60&#176;/6.0v.</td>
		</tr>
		<tr height="48">
			<td height="48" style="height:48px;width:87px;">Mechanical Pipettes</td>
			<td style="width:111px;">Dragon Laboratory Instruments Limited</td>
			<td style="width:87px;">YE5K693181</td>
			<td style="width:275px;">The pipettes cover volume range of 0.1 &#956;l to 2.5 &#956;l</td>
		</tr>
	</tbody>
</table>

measurement of dynamic force acted on water strider leg jumping upward by the pvdf film sensor

Este estudo teve como objetivo fazer uma explicação para o fenômeno na natureza que strider da água geralmente pula ou desliza sobre a superfície da água facilmente, mas rapidamente, com sua locomoção de pico de velocidade atingindo 150 cm/s. Em primeiro lugar, observamos a microestrutura e a hierarquia das pernas de strider da água usando o microscópio eletrônico de varredura. Com base na morfologia observada das pernas, foi estabelecido um modelo teórico do destacamento da superfície da água, que explicou a capacidade dos striders água para deslizar na superfície da água sem esforço em termos de redução de energia. Em segundo lugar, um sistema de medição de força dinâmica foi concebido utilizando o medidor de película PVDF com excelente sensibilidade, que poderia detectar o processo de interação toda. Posteriormente, um único pé em contacto com a água foi puxado para cima em diferentes velocidades, e a força de adesão foi medida ao mesmo tempo. Os resultados do experimento partido sugeriram uma compreensão profunda do pulo rápido de striders da água.

A relação entre força de aderência e velocidade de levantamento é mostrada na tabela 1. Aumenta a velocidade do levantamento de 0,01 m/s a 0,3 m/s, force a adesão entre a água superfície e perna diminui drasticamente a partir de 0,10-0,03. Os resultados do experimento partido mostraram que a força de adesão máxima iria diminuir drasticamente, como o aumento de velocidade do levantamento, que indicou que os striders da água pode se sentir confortáveis se movem...

Watch this Scientific Journal Video about Measurement of Dynamic Force Acted on Water Strider Leg Jumping Upward by the PVDF Film Sensor at JoVE.com

Measurement of Dynamic Force Acted on Water Strider Leg Jumping Upward by the PVDF Film Sensor

Medição de força dinâmica Agida na perna de Strider da água, saltar para cima pelo Sensor de película de PVDF

O protocolo aqui é dedicado a investigar o livre e rápida manobra de strider da água na superfície da água. O protocolo inclui observar a microestrutura de pernas e medir a força de adesão quando partem da superfície da água em diferentes velocidades.

This study aimed to make an explanation for the phenomenon in nature that water strider usually jumps or glides on the water surface easily but quickly, ...

measurement-dynamic-force-acted-on-water-strider-leg-jumping-upward

Research

JoVE Journal

Engineering

5.9K visualizações.  Tianjin University. O protocolo aqui é dedicado a investigar o livre e rápida manobra de strider da água na superfície da água. O protocolo inclui observar a microestrutura de pernas e medir a força de adesão quando partem da superfície da água em diferentes velocidades.

Vídeo: Measurement of Dynamic Force Acted on Water Strider Leg Jumping Upward by the PVDF Film Sensor

The Preparation of Electrohydrodynamic Bridges from Polar Dielectric Liquids

Horizontal and vertical liquid bridges are simple and powerful tools for exploring the interaction of high intensity electric fields (8-20 kV/cm) and polar dielectric liquids. These bridges are unique from capillary bridges in that they exhibit extensibility beyond a few millimeters, have complex bi-directional mass transfer patterns, and emit non-Planck infrared radiation. A number of common solvents can form such bridges as well as low conductivity solutions and colloidal suspensions. The macroscopic behavior is governed by electrohydrodynamics and provides a means of studying fluid flow phenomena without the presence of rigid walls. Prior to the onset of a liquid bridge several important phenomena can be observed including advancing meniscus height (electrowetting), bulk fluid circulation (the Sumoto effect), and the ejection of charged droplets (electrospray). The interaction between surface, polarization, and displacement forces can be directly examined by varying applied voltage and bridge length. The electric field, assisted by gravity, stabilizes the liquid bridge against Rayleigh-Plateau instabilities. Construction of basic apparatus for both vertical and horizontal orientation along with operational examples, including thermographic images, for three liquids (e.g., water, DMSO, and glycerol) is presented.

Horizontal and vertical electrohydrodynamic liquid bridges are simple and powerful tools for exploring the interaction of high intensity electric fields and polar dielectric liquids. The construction of basic apparatus and operational examples, including thermographic images, for three liquids (e.g., water, DMSO, and glycerol) is presented.

A preparação de eletro Pontes de Polar dielétricos líquidos

Horizontal and vertical liquid bridges are simple and powerful tools for exploring the interaction of high intensity electric fields (8-20 kV/cm) and ...

Engenharia

Investigating Single Molecule Adhesion by Atomic Force Spectroscopy

Atomic force spectroscopy is an ideal tool to study molecules at surfaces and interfaces. An experimental protocol to couple a large variety of single molecules covalently onto an AFM tip is presented. At the same time the AFM tip is passivated to prevent unspecific interactions between the tip and the substrate, which is a prerequisite to study single molecules attached to the AFM tip. Analyses to determine the adhesion force, the adhesion length, and the free energy of these molecules on solid surfaces and bio-interfaces are shortly presented and external references for further reading are provided. Example molecules are the poly(amino acid) polytyrosine, the graft polymer PI-g-PS and the phospholipid POPE (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine). These molecules are desorbed from different surfaces like CH3-SAMs, hydrogen terminated diamond and supported lipid bilayers under various solvent conditions. Finally, the advantages of force spectroscopic single molecule experiments are discussed including means to decide if truly a single molecule has been studied in the experiment.

A protocol to couple a large variety of single molecules covalently onto an AFM tip is presented. Procedures and examples to determine the adhesion force and free energy of these molecules on solid supports and bio-interfaces are provided.

Investigando única molécula de adesão de Força Atômica Spectroscopy

Atomic force spectroscopy is an ideal tool to study molecules at surfaces and interfaces. An experimental protocol to couple a large variety of single ...

How to Build a Vacuum Spring-transport Package for Spinning Rotor Gauges

The spinning rotor gauge (SRG) is a high-vacuum gauge often used as a secondary or transfer standard for vacuum pressures in the range of 1.0 x 10-4 Pa to 1.0 Pa. In this application, the SRGs are frequently transported to laboratories for calibration. Events can occur during transportation that change the rotor surface conditions, thus changing the calibration factor. To assure calibration stability, a spring-transport mechanism is often used to immobilize the rotor and keep it under vacuum during transport. It is also important to transport the spring-transport mechanism using packaging designed to minimize the risk of damage during shipping. In this manuscript, a detailed description is given on how to build a robust spring-transport mechanism and shipping container. Together these form a spring-transport package. The spring-transport package design was tested using drop-tests and the performance was found to be excellent. The present spring-transport mechanism design keeps the rotor immobilized when experiencing shocks of several hundred g (g = 9.8 m/sec2 and is the acceleration due to gravity), while the shipping container assures that the mechanism will not experience shocks greater than about 100 g during common shipping mishaps (as defined by industry standards).

Here we describe how to build a robust spring-transport mechanism for a spinning rotor gauge. This device securely immobilizes the rotor and keeps it under vacuum during transportation. We also describe packaging that minimizes the risk of damage during transport. Tests show our design works for typical shocks during transport.

Como construir um pacote Spring-transporte a vácuo para Spinning Rotor Gauges

The spinning rotor gauge (SRG) is a high-vacuum gauge often used as a secondary or transfer standard for vacuum pressures in the range of 1.0 x 10-4 Pa to ...

Quantitative Hardness Measurement by Instrumented AFM-indentation

In this work, a combination of amplitude-modulated non-contact atomic force microscopy and atomic force spectroscopy is applied for instrumented hardness measurements on an Au(111) surface with atomistic resolution of single plasticity events. A careful experimental procedure is described that includes the force sensor selection, its calibration, the calibration of the cantilever deflection detection system, and the minimization of instrumental drift for accurate and reproducible force-distance measurements. Also, a method for the data analysis is presented that allows the extraction of force-penetration curves from recorded force-distance curves. A typical curve displays a clear elastic deformation regime up to the first plasticity event, or pop-in, with a length in the range of one to two Burger's vectors. Later plasticity events exhibit the same magnitude. The work of plasticity is further extracted from the measurements. Finally, the hardness is determined in combination with the indentation curve using non-contact atomic force microscopy images of the remaining indents.

This experimental protocol describes how atomic force microscopy can be used to measure hardness at the true nanometer scale and to detect single atomistic plasticity events.

Medição de dureza quantitativa por Instrumented AFM-recuo

In this work, a combination of amplitude-modulated non-contact atomic force microscopy and atomic force spectroscopy is applied for instrumented hardness ...

Optical Trap Loading of Dielectric Microparticles In Air

We demonstrate a method to trap a selected dielectric microparticle in air using radiation pressure from a single-beam gradient optical trap. Randomly scattered dielectric microparticles adhered to a glass substrate are momentarily detached using ultrasonic vibrations generated by a piezoelectric transducer (PZT). Then, the optical beam focused on a selected particle lifts it up to the optical trap while the vibrationally excited microparticles fall back to the substrate. A particle may be trapped at the nominal focus of the trapping beam or at a position above the focus (referred to here as the levitation position) where gravity provides the restoring force. After the measurement, the trapped particle can be placed at a desired position on the substrate in a controlled manner. 
In this protocol, an experimental procedure for selective optical trap loading in air is outlined. First, the experimental setup is briefly introduced. Second, the design and fabrication of a PZT holder and a sample enclosure are illustrated in detail. The optical trap loading of a selected microparticle is then demonstrated with step-by-step instructions including sample preparation, launching into the trap, and use of electrostatic force to excite particle motion in the trap and measure charge. Finally, we present recorded particle trajectories of Brownian and ballistic motions of a trapped microparticle in air. These trajectories can be used to measure stiffness or to verify optical alignment through time domain and frequency domain analysis. Selective trap loading enables optical tweezers to track a particle and its changes over repeated trap loadings in a reversible manner, thereby enabling studies of particle-surface interaction.

A protocol for launching and stably trapping selected dielectric microparticles in air is presented.

Armadilha óptica carregamento de dielétrico micropartículas no ar

We demonstrate a method to trap a selected dielectric microparticle in air using radiation pressure from a single-beam gradient optical trap. Randomly ...

Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source

Silicon photonic chips have the potential to realize complex integrated quantum information processing circuits, including photon sources, qubit manipulation, and integrated single-photon detectors. Here, we present the key aspects of preparing and testing a silicon photonic quantum chip with an integrated photon source and two-photon interferometer. The most important aspect of an integrated quantum circuit is minimizing loss so that all of the generated photons are detected with the highest possible fidelity. Here, we describe how to perform low-loss edge coupling by using an ultra-high numerical aperture fiber to closely match the mode of the silicon waveguides. By using an optimized fusion splicing recipe, the UHNA fiber is seamlessly interfaced with a standard single-mode fiber. This low-loss coupling allows the measurement of high-fidelity photon production in an integrated silicon ring resonator and the subsequent two-photon interference of the produced photons in a closely integrated Mach-Zehnder interferometer. This paper describes the essential procedures for the preparation and characterization of high-performance and scalable silicon quantum photonic circuits.

Silicon photonic chips have the potential to realize complex integrated quantum systems. Presented here is a method for preparing and testing a silicon photonic chip for quantum measurements.

Medição de Interferência Quântica em uma fonte de silício anel ressonador Photon

Silicon photonic chips have the potential to realize complex integrated quantum information processing circuits, including photon sources, qubit ...

Generation of Size-controlled Poly (ethylene Glycol) Diacrylate Droplets via Semi-3-Dimensional Flow Focusing Microfluidic Devices

Uniform and size-controllable poly (ethylene glycol) diacrylate (PEGDA) droplets could be produced via the flow focusing process in a microfluidic device. This paper proposes a semi-three-dimensional (semi-3D) flow-focusing microfluidic chip for droplet formation. The polydimethylsiloxane (PDMS) chip was fabricated using the multi-layer soft lithography method. Hexadecane containing surfactant was used as the continuous phase, and PEGDA with the ultraviolet (UV) photo-initiator was the dispersed phase. Surfactants allowed the local surface tension to drop and formed a more cusped tip which promoted breaking into tiny micro-droplets. As the pressure of dispersed phase was constant, the size of droplets became smaller with increasing continuous phase pressure before dispersed phase flow was broken off. As a result, droplets with size variation from 1 &#181;m to 80 &#181;m in diameter could be selectively achieved by changing the pressure ratio in two inlet channels, and the average coefficient of variation was estimated to be below 7%. Furthermore, droplets could turn into micro-beads by UV exposure for photo-polymerization. Conjugating biomolecules on such micro-beads surface have many potential applications in the fields of biology and chemistry.

Generation of Size-controlled Poly ethylene Glycol Diacrylate Droplets via Semi-3-Dimensional Flow Focusing Microfluidic Devices

Here, we present a protocol to illustrate the fabrication processes and verifying experiments of a semi-three-dimensional (semi-3D) flow-focusing microfluidic chip for droplet formation.

Geração de tamanho controlado poli (etileno glicol) Diacrylate gotículas através de Semi-3-Dimensional Flow focando Microfluidic dispositivos

Uniform and size-controllable poly (ethylene glycol) diacrylate (PEGDA) droplets could be produced via the flow focusing process in a microfluidic device. ...

Near-Infrared Temperature Measurement Technique for Water Surrounding an Induction-heated Small Magnetic Sphere

A technique to measure the temperature of water and non-turbid aqueous media surrounding an induction-heated small magnetic sphere is presented. This technique utilizes wavelengths of 1150 and 1412 nm, at which the absorption coefficient of water is dependent on temperature. Water or a non-turbid aqueous gel containing a 2.0-mm- or 0.5-mm-diameter magnetic sphere is irradiated with 1150 nm or 1412 nm incident light, as selected using a narrow bandpass filter; additionally, two-dimensional absorbance images, which are the transverse projections of the absorption coefficient, are acquired via a near-infrared camera. When the three-dimensional distributions of temperature can be assumed to be spherically symmetric, they are estimated by applying inverse Abel transforms to the absorbance profiles. The temperatures were observed to consistently change according to time and the induction heating power.

A technique utilizing wavelengths of 1150 and 1412 nm to measure the temperature of water surrounding an induction-heated small magnetic sphere is presented.

Técnica de medição de temperatura infravermelha para a água ao redor de uma esfera magnética pequena aquecida a indução

A technique to measure the temperature of water and non-turbid aqueous media surrounding an induction-heated small magnetic sphere is presented. This ...

Fabrication of Flexible Image Sensor Based on Lateral NIPIN Phototransistors

Flexible photodetectors have been intensely studied for the use of curved image sensors, which are a crucial component in bio-inspired imaging systems, but several challenging points remain, such as a low absorption efficiency due to a thin active layer and low flexibility. We present an advanced method to fabricate a flexible phototransistor array with an improved electrical performance. The outstanding electrical performance is driven by a low dark current owing to deep impurity doping. Stretchable and flexible metal interconnectors simultaneously offer electrical and mechanical stabilities in a highly deformed state. The protocol explicitly describes the fabrication process of the phototransistor using a thin silicon membrane. By measuring I-V characteristics of the completed device in deformed states, we demonstrate that this approach improves the mechanical and electrical stabilities of the phototransistor array. We expect that this approach to a flexible phototransistor can be widely used for the applications of not only next-generation imaging systems/optoelectronics but also wearable devices such as tactile/pressure/temperature sensors and health monitors.

We present a detailed method to fabricate a deformable lateral NIPIN phototransistor array for curved image sensors. The phototransistor array with an open mesh form, which is composed of thin silicon islands and stretchable metal interconnectors, provides flexibility and stretchability. The parameter analyzer characterizes the electrical property of the fabricated phototransistor.

Fabricação de imagem flexível Sensor baseado no NIPIN Lateral Phototransistors

Flexible photodetectors have been intensely studied for the use of curved image sensors, which are a crucial component in bio-inspired imaging systems, ...

O-cresol Concentration Online Measurement Based On Near Infrared Spectroscopy Via Partial Least Square Regression

Unlike macroscopic process variables, near-infrared spectroscopy provides process information at the molecular level and can significantly improve the prediction of the components in industrial processes. The ability to record spectra for solid and liquid samples without any pretreatment is advantageous and the method is widely used. However, the disadvantages of analyzing high-dimensional near-infrared spectral data include information redundancy and multicollinearity of the spectral data. Thus, we propose to use partial least squares regression method, which has traditionally been used to reduce the data dimensionality and eliminate the collinearity between the original features. We implement the method for predicting the o-cresol concentration during the production of polyphenylene ether. The proposed approach offers the following advantages over component regression prediction methods: 1) partial least squares regression solves the multicollinearity problem of the independent variables and effectively avoids overfitting, which occurs in a regression analysis due to the high correlation between the independent variables; 2) the use of the near-infrared spectra results in high accuracy because it is a non-destructive and non-polluting method to obtain information at microscopic and molecular scales.

The protocol describes a method of predicting o-cresol concentration during the production of polyphenylene ether using near-infrared spectroscopy and partial least squares regression. To describe the process more clearly and completely, an example of predicting the o-cresol concentration during the production of polyphenylene is used to clarify the steps.

Medição on-line de concentração de o-cresol com base em espectroscopia infravermelha próxima via regressão parcial pelo menos quadrado

Unlike macroscopic process variables, near-infrared spectroscopy provides process information at the molecular level and can significantly improve the ...