이 작품에 대한 부분적인 재정 지원은 물 장비 및 위스콘신 - 밀워키 (IIP-0968887)과 마켓 대학 (IIP-0968844)의 대학에있는 정책에 대한 산업 / 대학 협동 연구 센터를 통해 미국 국립 과학 재단 (National Science Foundation)에 의해 제공되었다. 우리는 도움이 토론 글렌 M. 워커, 우 진 장과 샨 Radhakrishnan 감사합니다.

1. 열 입자 감지 (TPD) <ol><li> 표준 반도체 공정 기술을 이용하여 2, 마이크로 머신에 의한 박막 실리콘 질화물 막, 및 온도 센서가 내장 마이크로 제조 실리콘 장치를 준비한다. 탈 (DI) 물 제조 장치를 씻어. 주 : 열 입자 탐지기를위한 미세 유체 소자의 제조 방법은 선행 문헌 2에 설명되어있다. </li><li> 마이크로 채널이 폴리 디메틸 실록산 (PDMS) 기판을 제조, (5)를 처리 표준 리소그래피를 이용한 몰드를 만들 SU8. 참고 : 채널 크기는 각각의 특정 입자의 차원을 위해 설계되었습니다. <ol><li> 염기의 1 비율 (30 mL) 및 제 (3 ml)에 경화 : 10 혼합하여 PDMS합니다. 금형에 PDMS를 붓고 잠시 진공 (5 ~ 10 분)에 노출하여 거품을 제거합니다. 진공 탈기 레벨에 임계 값이 아니며 가스 bubb까지 계속한다 : 참고레 완전히 혼합 된 PDMS에서 제거됩니다. </li><li> PDMS를 치료하기 위해 2 시간 동안 열판 (~ 70 ° C)에 금형을 놓습니다. 금형 손상되지 않도록 매우 조심스럽게이어서 PDMS 벗겨져. 주 : 진공 레벨이 임계 값이 아니다. </li></ol></li><li> 수동 펀치를 사용하여, 일단 PTFE 관용 단단한 구멍 (1 mm)를 펀치. PDMS 저수지를 만들기 위해 다른 쪽 끝에서 큰 펀치 (2mm)를 사용합니다. 현미경 장치 위에 펀칭 미세 통로를 배치하고, 마이크로 채널 (도 1a)의 중심에 정렬 RTD. </li><li> 전기 인터페이스에있어서, 콘택 패드의 위치에서의 전기 핀을 연결하고 잠금 나사를 조여. 높이 조절 핀 (포고 핀) 장치의 올바른 전극 패드에 앉아 있는지 확인하십시오. </li><li> 1.5 ㎖의 튜브에 DI 물 100 ㎕의 농축 PS 비드의 10 μl를 희석. </li><li> (글리세롤의 2.7 μl를 추가, 1.26 구슬이 중성 부력을 유지 PS를 보장하기 위해g / cm 3) DI 물에 폴리스티렌 (PS) 비드 밀도 유체 밀도 (일치 1.05 g / cm 3). </li><li> 일단 채널 및 1 mL 유리 주사기 타단에 PTFE 튜브를 연결한다. DI 물 0.5 mL를 유리 주사기를 입력합니다. 참고 : 튜브의 누설을 방지 할 수있는 권리 펀치 크기를 선택하여 만든 단단한 피팅. </li><li> 컴퓨터 제어 주사기 펌프에 주사기를 가득 탈 이온수를 놓습니다. 유체 저장조 줄곧 전체 채널을 채우기 위해 채널에 물 (5-20 μL / 분)를 누른다. </li><li> 저장조에 평형 비드 용액 10 ㎕를 부하하고 주사기 펌프에 흐름 방향을 변화시켜 마이크로 채널에 비드 용액을 소개한다. </li><li> (그림 2) 원 / m로 저항을 측정하는 동안 컴퓨터 제어 소스 / 미터를 통해 직류 전류 1mA 바이어스하고 측정 된 데이터를 정렬하여 RTD를 켭니다. 주 : 실험 기간 동안, 센서 바이어스; 따라서, 온도를 연속적으로 카운팅 실험이 끝날 때까지 측정한다. RTD 센서가 전기적으로 연속적으로 카운팅 실험이 끝날 때까지의 온도를 측정하기 위해 100 μA에서 1mA의 범위 DC 전류를인가함으로써 바이어스된다. 이는 잡음 레벨과 검출 신호 진폭 간의 트레이드 오프가 존재하기 때문에 정확한 전류 레벨을 선택하는 것이 중요하다. 주사기 펌프는 마이크로 채널의 플로우를 생성하기 위해 사용된다. TPD 실험을 수행 할 수있는 적절한 유량을 선택하면 측정 속도로 제한된다. 이 속도는 전기 장치 및 측정 속도의 열 시상수의 함수이다. 열 입자 검출 실험 결과를도 3에 나타낸다. </li><li> Callendar-van Dusen 방정식 (6)을 이용하여 온도 측정 저항의 데이터를 변환하기 위해 개발 된 데이터 처리 소프트웨어 (LabVIEW를) 사용. </li></ol> 열 (2)마이크로 열량계를 사용하여 액체 물질의 특성 <ol><li> 이 과정에서, 열 확산율 및 샘플의 비열을 측정하는 온 - 칩 열량계 장치 (도 4a) (3)를 사용한다. 참고 : 각 죽을에서 2 마이크로 열량계 챔버 (도 4b는)이있다. 각 챔버는 2 입구와 하나의 출구가 있습니다. 그리고 각 챔버는 히터와 통합 RTD 센서를 가지고 있습니다. </li><li> 장치 홀더 (그림 4C)에 마이크로 열량계 장치를 놓습니다. 홀더 피팅 미세 유체 입구 및 출구에 장치를 맞 춥니 다. 장치의 상단에있는 PDMS 도장 층을 놓습니다. </li><li> 장치 홀더에 전기 연결 핀을 설치하고 홀더 나사를 잠급니다. 참고 : 높이 조절 포고 핀은 전기 접촉 패드와 정렬되어 있는지 확인합니다. </li><li> 장치 홀더 (그림 4D)에 자기 래치와 미세 유체 인터페이스 층을 설치합니다. PT를 연결합니다FE는 입구와 출구 모두 튜브. 샘플 로딩 주사기 펌프에 하나의 입구를 연결 엔탈피이 경우 측정되지 않는 한, 다른 하나를 닫는다. </li><li> 마이크로 채널 및 챔버로 샘플을로드하기 위해 개발 된 컴퓨터 제어 프로그램을 사용하십시오. 참고 :이 프로그램은 박막 중단 챔버에 과도한 압력을 해제 중단 흐름을 사용합니다. <ol><li> 유리 주사기로 300 μL 샘플을로드하고 주사기 펌프에 놓습니다. 점도가 높은 샘플 (예를 들어, 글리세롤 및 이온 성 액체)에 대한 매우 느린 (0.25 μL / 분) 일정한 유량을 사용합니다. 비열 측정을위한 열 확산율 측정 및 이온 성 액체 글리세린 샘플을 사용합니다. </li></ol></li><li> 측정 <ol><li> 열 확산율 측정 <ol><li> 도 5a에 도시 된 바와 같이, 측정 설정을 연결합니다. 마이크로 열량계 챔버로 글리세롤 샘플을로드합니다. 난방을위한 수정 된 컴퓨터 제어 프로그램을 실행<html> T 침투 시간 측정. </li><li> 측정 된 열 침투 시간 7에서 열 확산을 계산하는 보정 열 침투 방정식을 사용하여 <img alt="식 (1)" src="/files/ftp_upload/52828/52828eq1.jpg" width="100" /> α는 열확산이고, L은 실의 두께가 (P)으로 인해 제조 공정 변화에 두께 보정 인자이고, t는 0 열 침투 시간이다. </li></ol></li><li> 비열 측정 <ol><li> 도 5b에 도시 된 바와 같이 TWA 측정 설정을 사용한다. 동일한 샘플 로딩 프로그램을 사용하여 챔버 내에서 이온 성 액체를 넣습니다. AC 온도 변동 (∂ T AC)의 진폭을 얻을 수있는 TWA 프로그램을 실행하고 계산하는 비열 식을 사용하는 특정, C P는, 각각의 이온 성 액체 샘플 8 열 : 28eq2.jpg &quot;폭 =&quot;117 &quot;/&gt; C 0 입력 파워 교정 인자이고, 입력 힘 P에서, ω는 구동 신호의 주파수이고, m은 액체 시료의 질량이다. </li></ol></li></ol></li></ol> 종이 기반 미세 유체 소자 3. 열량 생화학 감지 <ol><li> 미세 박막 (40 ~ 50 nm의 니켈) RTD 센서를 사용합니다. RTD 센서의 제조 단계 이전 작품 4에 설명되어 있습니다. </li><li> 종이 기반의 채널 제조 4, 용지를 디자인 패턴 (L 자형)과 미세 유체 채널을 절단 칼 플로터를 사용합니다. , 커팅 매트 위에 종이를 놓고 종이와 칼 플로터 커팅 매트를로드하고, 미세 유체 종이 채널 4를 잘라 적절한 조리법을 사용합니다. </li><li> 장치 및 채널 통합, RTD 센서에 용지를 통합하는 아크릴계 점착제 층 (5 μm의)를 사용합니다. 깨끗한 B를 사용하여짐을 싣다는 장치에 용지를 밀어 기포를 (그림 6A)를 제거합니다. 아크릴 필름은 RTD 센서 위에 종이를 보유하는 접착제 층이다. </li><li> 효소 활성화를위한, GOD 효소 활성화의 50 mM 아세트산 나트륨 완충액을 사용한다. 1 ㎎ / ㎖ 솔루션을 만들기 위해 아세트산 나트륨 완충액 1 ㎖로 신 효소의 1 mg을 추가합니다. 5.1 용액의​​ pH를 조정한다. 주 : 5.1 용액의​​ pH를 유지하기 위해 아세트산 나트륨 완충액, 아세트산의 양을 조정한다. </li><li> 바이어스 1mA의 DC 전류 RTD는 RTD를 활성화하고 저항 실험 (~ 4 분) 이후에 정착하면서 지속적으로 저항 소스 / 미터 측정을 시작합니다. 참고 : 그림 6b는 종이 기반의 열량 테스트의 측정 설정을 보여줍니다. </li><li> 피펫을 통해 종이 마이크로 채널 (고정 부위)의 중심 제조 GOD 용액 2 μl를 소개한다. 검출 된 온도 (그림 7A)는 T 시작해야합니다O 감소. 참고 :이 냉각 효과가 함께 샘플의 높은 동작 측온 저항체의 온도와 증발 때문이다. </li><li> 글루코스 농도를 측정하기 위해, 채널 입구 표준 혈당 조절 용액 (9)을 도입하고, 반응에 의한 저항 변화를 측정한다. 모든 (높음, 보통 및 낮은 농도) 다른 혈당 조절 솔루션이 실험을 반복 저항 데이터를 저장합니다. </li><li> 니켈 -은 Callandar RTD 및 반 Dusen 방정식 저항 (TCR)의 온도 계수를 이용하여, 온도에 대한 저항 변화를 변환한다. 글루코오스 반응 엔탈피 및 GOD 효소 (Δ H = -80 kJ의 / 몰)을 고려하고 수학 식 (10)의 농도를 이용하여 각 샘플에서 포도당의 농도를 계산한다 : <img alt="식 (3)" src="/files/ftp_upload/52828/52828eq3.jpg" width="83" /> N p를 몰 농도, C가 감지되는 경우 <sub&gt; P는 시스템의 열용량 및 ΔT는 온도를 계산한다. </li></ol>

<ol>
	<li>Zhang, H., Chon, C., Pan, X., Li, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methods+for+counting+particles+in+microfluidic+applications.">Methods for counting particles in microfluidic applications.</a> Microfluid Nanofluid. 7 (6), 739-749 (2009).</li><li>Vutha, A. K., Davaji, B., Lee, C. H., Walker, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+microfluidic+device+for+thermal+particle+detection.">A microfluidic device for thermal particle detection.</a> Microfluid Nanofluid. 17 (5), 871-878 (2014).</li><li>Davaji, B., Bak, H. J., Chang, W. J., Lee, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Novel+On-chip+Three-dimensional+Micromachined+Calorimeter+with+Fully+Enclosed+and+Suspended+Thin-film+Chamber+for+Thermal+Characterization+of+Liquid+Samples.">A Novel On-chip Three-dimensional Micromachined Calorimeter with Fully Enclosed and Suspended Thin-film Chamber for Thermal Characterization of Liquid Samples.</a> Biomicrofluidics. 8 (3), 034101-034113 (2014).</li><li>Davaji, B., Lee, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+paper-based+calorimetric+microfluidics+platform+for+bio-chemical+sensing.">A paper-based calorimetric microfluidics platform for bio-chemical sensing.</a> Biosens. Bioelectron. 59, 120-126 (2014).</li><li>Liu, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Process+research+of+high+aspect+ratio+microstructure+using+SU-8+resist.">Process research of high aspect ratio microstructure using SU-8 resist.</a> Microsystem Technologies. 10, 265-268 (2004).</li><li>Dusen, M. S. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Platinum-resistance+thermometry+at+low+temperatures.">Platinum-resistance thermometry at low temperatures.</a> J. Am. Chem. Soc. 47 (2), 326-332 (1925).</li><li>Arpaci, V. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Conduction Heat Transfer. , (1966).</li><li>Garden, J. L., Chteau, E., Chaussy, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+sensitive+ac+nanocalorimeter+for+microliter-scale+liquids+or+biological+samples.">Highly sensitive ac nanocalorimeter for microliter-scale liquids or biological samples.</a> Appl. Phys. Lett. 84, 3597-3599 (2004).</li><li>Kilo, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+a+New+Blood+Glucose+Monitoring+System+with+Auto-Calibration.">Evaluation of a New Blood Glucose Monitoring System with Auto-Calibration.</a> Diabetes Technol. Ther. 7 (2), 283-294 (2005).</li><li>Scheper, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Thermal Biosensors Bioactivity Bioaffinity (Advances in Biochemical Engineering/Biotechnology). , (1999).</li></ol>

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Different thermal measurement techniques in microfluidic devices and their respective setup procedures are presented in this work. These thermal measurement methods such as thermal conductivity monitoring, thermal penetration time, amplitude of AC thermal fluctuations, and amplitude measurement of the generated heat are used to detect specific substances and investigate different reactions and interactions. 
The thermal time constant plays a key role in the aforementioned thermal measurement t...

세 가지 다른 마이크로 크기의 열 측정 기술은이 문서에 제시되어있다. 미세 유체 장치의 세 가지 상이한 구성은 열 입자 검출부 (TPD), 열적 특성 (열전도율 및 비열), 및 화학 반응과 상호 작용 열량 검출에 사용된다. 열 입자 검출 검출 및 미세 유체 장치에서 입자를 계산하는 것은 널리, 환경 산업, 생물 응용 프로그램 (1)에 사용됩니다. TPD는 미세 유체 장치 2 열 측정의 새로운 응용 프로그램 중 하나입니다. 검출 및 입자 크기에 기초하여 입자를 계수 열 전달을 사용하여 시스템의 복잡성, 비용 및 크기를 감소시킨다. 다른 방법, 복잡한 광학 또는 복잡한 전기 측정 및 고급 신호 처리 소프트웨어에서 입자를 검출하기 위해 사용된다. 열 체인지마이크로 열량계를 사용하여 액체 물질의 cterization 액체 시료의 열 특성은 미세 유체 장치의 열 측정의 두 번째 응용 프로그램입니다. 마이크로 스케일 열량을 수행하면 샘플 소모를 줄이고, 종래의 벌크 열량 방법에 비해 더 높은 반복성을 제공하여 정확도를 증가시킬 것이다. 온 - 칩 마이크로 - 열량계 장치를 이용하여 열전도율 및 비열 측정을위한 절차는 다른 세 제시된다. 열전도율 측정 용 히트 침투 시간 기술 및 마이크로 유체 디바이스들에서 비열 측정을위한 열 파 분석 (TWA)의 세부 사항은 프로토콜 절에서 설명된다. 열량 바이오 화학에있는 검색, 탐지 종이 기반 미세 유체 소자 열 측정의 또 다른 응용 프로그램은 종이 기반 미세 유체에서 생화학 감지입니다. 에서 모세관 작용종이의 다공질 구조가 액체를 운반 마이크로 채널 거품 개시 문제를 피할 수있다. 종이 기반의 미세 유체 소자에서 가장 일반적인 검출 메커니즘은 광학 또는 전기 화학적 기술이다. 광 검출은 높은 복잡성 앓고 고급 화상 처리 소프트웨어의 필요성이 검출 된 신호를 양자화하는. 이들은 활성 반응 부산물을 생산에 적용 할 수 있기 때문에, 전기 화학 탐지가 또한 제한된다. 최근 소개 열량 종이 기반 생화학 센서 플랫폼 (4)은 종이 기반 마이크로 유체 시스템 및 라벨없는 열 감지 메커니즘을 이용한다. 종이 기반의 미세 유체 플랫폼에 글루코스 옥시 다제 (GOD) 효소를 이용한 글루코스의 열량 검출 절차는 프로토콜 부분에 제시되어있다. 본 연구의 목적은 미세 유체 소자에서 열 측정 기술의 능력을 입증하는 것이다. 장치 혼합물 준비N, 액체 시료 처리 및 저항 온도 감지기 (RTD) 센서 여기 및 측정은 다음 절에 제시되어있다.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Polydimethylsiloxane (PDMS)&#160;</td>
			<td>Dow Corning</td>
			<td>Sylgard 184</td>
			<td></td>
		</tr>
		<tr>
			<td>PS beads - 90 um&#160;</td>
			<td>Corpuscular</td>
			<td>100265</td>
			<td></td>
		</tr>
		<tr>
			<td>PS beads - 200 um&#160;</td>
			<td>Corpuscular</td>
			<td>100271</td>
			<td></td>
		</tr>
		<tr>
			<td>Glycerol</td>
			<td>SigmaAldrich</td>
			<td>G5516</td>
			<td></td>
		</tr>
		<tr>
			<td>GOD enzyme</td>
			<td>SigmaAldrich</td>
			<td>G7141</td>
			<td></td>
		</tr>
		<tr>
			<td>Glucose Control Solution-Low</td>
			<td>Bayer contour</td>
			<td>Low Control</td>
			<td></td>
		</tr>
		<tr>
			<td>Glucose Control Solution-Normal</td>
			<td>Bayer contour</td>
			<td>Normal Control</td>
			<td></td>
		</tr>
		<tr>
			<td>Glucose Control Solution-High</td>
			<td>Bayer contour</td>
			<td>High Control</td>
			<td></td>
		</tr>
		<tr>
			<td>Chromatography filter paper</td>
			<td>Whatman</td>
			<td>3001-845</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass</td>
			<td>VWR&#160;</td>
			<td>48393-106</td>
			<td></td>
		</tr>
		<tr>
			<td>Acrylic Film</td>
			<td>Nitto Denko</td>
			<td>5600</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass syringe (1 mL)</td>
			<td>Hamilton</td>
			<td>1001</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe pump</td>
			<td>New Era</td>
			<td>NE-500</td>
			<td></td>
		</tr>
		<tr>
			<td>knife plotter</td>
			<td>Silhouette</td>
			<td>portrait</td>
			<td></td>
		</tr>
		<tr>
			<td>Current Preamplifier</td>
			<td>Stanford Research</td>
			<td>SR-570</td>
			<td></td>
		</tr>
		<tr>
			<td>Ocilloscope</td>
			<td>Agilent</td>
			<td>DSO 2420A</td>
			<td></td>
		</tr>
		<tr>
			<td>Signal Generator</td>
			<td>HP</td>
			<td>HP3324A</td>
			<td></td>
		</tr>
		<tr>
			<td>Lock-in Amplifire</td>
			<td>Stanford Research</td>
			<td>SRS-830</td>
			<td></td>
		</tr>
		<tr>
			<td>Source/meter 2400</td>
			<td>Keithley</td>
			<td>2400</td>
			<td></td>
		</tr>
		<tr>
			<td>Source/meter 2600</td>
			<td>Keithley</td>
			<td>2436A</td>
			<td></td>
		</tr>
	</tbody>
</table>

thermal measurement techniques in analytical microfluidic devices

Thermal measurement techniques have been used for many applications such as thermal characterization of materials and chemical reaction detection. Micromachining techniques allow reduction of the thermal mass of fabricated structures and introduce the possibility to perform high sensitivity thermal measurements in the micro-scale and nano-scale devices. Combining thermal measurement techniques with microfluidic devices allows performing different analytical measurements with low sample consumption and reduced measurement time by integrating the miniaturized system on a single chip. The procedures of thermal measurement techniques for particle detection, material characterization, and chemical detection are introduced in this paper.

그림 3은 측정 된 온도 신호의 플롯을 보여줍니다. 해당 광학 이미지 비드의 존재 하에서 생성 된 신호는 마이크로 채널에서 미세 구 PS 비드의 성공적인 검출을 나타낸다. 마이크로 채널을 통과하는 액체의 열전도 PS 비드의 존재로 인해 변경된다. 채널의 열전도율의 변화는 마이크로 채널에서의 열전달에 영향을주지한다. 마이크로 채널에서의 열 전달의 변화는 저항의 변동 (?...

Watch this Scientific Journal Video about Thermal Measurement Techniques in Analytical Microfluidic Devices at JoVE.com

Thermal Measurement Techniques in Analytical Microfluidic Devices

Here, we present three protocols for thermal measurements in microfluidic devices.

분석 미세 유체 장치의 열 측정 기술

Thermal measurement techniques have been used for many applications such as thermal characterization of materials and chemical reaction detection. ...

thermal-measurement-techniques-in-analytical-microfluidic-devices

Research

JoVE Journal

Engineering

9.5K 조회수.  Marquette University. Here, we present three protocols for thermal measurements in microfluidic devices. 

비디오: Thermal Measurement Techniques in Analytical Microfluidic Devices

Characterization of Thermal Transport in One-dimensional Solid Materials

The TET (transient electro-thermal) technique is an effective approach developed to measure the thermal diffusivity of solid materials, including conductive, semi-conductive or nonconductive one-dimensional structures. This technique broadens the measurement scope of materials (conductive and nonconductive) and improves the accuracy and stability. If the sample (especially biomaterials, such as human head hair, spider silk, and silkworm silk) is not conductive, it will be coated with a gold layer to make it electronically conductive. The effect of parasitic conduction and radiative losses on the thermal diffusivity can be subtracted during data processing. Then the real thermal conductivity can be calculated with the given value of volume-based specific heat (&#961;cp), which can be obtained from calibration, noncontact photo-thermal technique or measuring the density and specific heat separately. In this work, human head hair samples are used to show how to set up the experiment, process the experimental data, and subtract the effect of parasitic conduction and radiative losses.

The TET (transient electro-thermal) technique is an effective approach developed to measure the thermal diffusivity of solid materials.

한 차원 고체 물질의 열 수송의 특성

The TET (transient electro-thermal) technique is an effective approach developed to measure the thermal diffusivity of solid materials, including ...

연구

공학

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.

공기에서 유전체 미세 입자의 광학 트랩로드

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

Solvent Bonding for Fabrication of PMMA and COP Microfluidic Devices

Thermoplastic microfluidic devices offer many advantages over those made from silicone elastomers, but bonding procedures must be developed for each thermoplastic of interest. Solvent bonding is a simple and versatile method that can be used to fabricate devices from a variety of plastics. An appropriate solvent is added between two device layers to be bonded, and heat and pressure are applied to the device to facilitate the bonding. By using an appropriate combination of solvent, plastic, heat, and pressure, the device can be sealed with a high quality bond, characterized as having high bond coverage, bond strength, optical clarity, durability over time, and low deformation or damage to microfeature geometry. We describe the procedure for bonding devices made from two popular thermoplastics, poly(methyl-methacrylate) (PMMA), and cyclo-olefin polymer (COP), as well as a variety of methods to characterize the quality of the resulting bonds, and strategies to troubleshoot low quality bonds. These methods can be used to develop new solvent bonding protocols for other plastic-solvent systems.

Solvent bonding is a simple and versatile method for fabricating thermoplastic microfluidic devices with high quality bonds. We describe a protocol to achieve strong, optically clear bonds in PMMA and COP microfluidic devices that preserve microfeature details, by a judicious combination of pressure, temperature, an appropriate solvent, and device geometry.

PMMA의 제조 및 COP 미세 유체 장치에 대한 솔벤트 본딩

Thermoplastic microfluidic devices offer many advantages over those made from silicone elastomers, but bonding procedures must be developed for each ...

Micro/Nano-scale Strain Distribution Measurement from Sampling Moir&#233; Fringes

This work describes the measurement procedure and principles of a sampling moir&#233; technique for full-field micro/nano-scale deformation measurements. The developed technique can be performed in two ways: using the reconstructed multiplication moir&#233; method or the spatial phase-shifting sampling moir&#233; method. When the specimen grid pitch is around 2 pixels, 2-pixel sampling moir&#233; fringes are generated to reconstruct a multiplication moir&#233; pattern for a deformation measurement. Both the displacement and strain sensitivities are twice as high as in the traditional scanning moir&#233; method in the same wide field of view. When the specimen grid pitch is around or greater than 3 pixels, multi-pixel sampling moir&#233; fringes are generated, and a spatial phase-shifting technique is combined for a full-field deformation measurement. The strain measurement accuracy is significantly improved, and automatic batch measurement is easily achievable. Both methods can measure the two-dimensional (2D) strain distributions from a single-shot grid image without rotating the specimen or scanning lines, as in traditional moir&#233; techniques. As examples, the 2D displacement and strain distributions, including the shear strains of two carbon fiber-reinforced plastic specimens, were measured in three-point bending tests. The proposed technique is expected to play an important role in the non-destructive quantitative evaluations of mechanical properties, crack occurrences, and residual stresses of a variety of materials.

Micro/Nano-scale Strain Distribution Measurement from Sampling Moir&amp;#233; Fringes

A sampling moir&#233; technique featuring 2-pixel and multi-pixel sampling methods for high-accuracy strain distribution measurements at the micro/nano-scale is presented here.

샘플링 모아레 프린지에서의 마이크로 / 나노 스케일 변형률 측정

This work describes the measurement procedure and principles of a sampling moir&#233; technique for full-field micro/nano-scale deformation measurements. ...

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.

크기 제어 폴 리 (에틸렌 글리콜) 빛 방울 장치를 통해 세미 3 차원 흐름 초점 미세의 세대

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

Simultaneous Measurement of Turbulence and Particle Kinematics Using Flow Imaging Techniques

Numerous problems in scientific and engineering fields involve understanding the kinematics of particles in turbulent flows, such as contaminants, marine micro-organisms, and/or sediments in the ocean, or fluidized bed reactors and combustion processes in engineered systems. In order to study the effect of turbulence on the kinematics of particles in such flows, simultaneous measurements of both the flow and particle kinematics are required. Non-intrusive, optical flow measurement techniques for measuring turbulence, or for tracking particles, exist but measuring both simultaneously can be challenging due to interference between the techniques. The method presented herein provides a low cost and relatively simple method to make simultaneous measurements of the flow and particle kinematics. A cross section of the flow is measured using a particle image velocimetry (PIV) technique, which provides two components of velocity in the measurement plane. This technique utilizes a pulsed-laser for illumination of the seeded flow field that is imaged by a digital camera. The particle kinematics are simultaneously imaged using a light emitting diode (LED) line light that illuminates a planar cross section of the flow that overlaps with the PIV field-of-view (FOV). The line light is of low enough power that it does not affect the PIV measurements, but powerful enough to illuminate the larger particles of interest imaged using the high-speed camera. High-speed images that contain the laser pulses from the PIV technique are easily filtered by examining the summed intensity level of each high-speed image. By making the frame rate of the high-speed camera incommensurate with that of the PIV camera frame rate, the number of contaminated frames in the high-speed time series can be minimized. The technique is suitable for mean flows that are predominantly two-dimensional, contain particles that are at least 5 times the mean diameter of the PIV seeding tracers, and are low in concentration.

The technique described herein offers a low cost and relatively simple method to simultaneously measure particle kinematics and turbulence in flows with low particle concentrations. The turbulence is measured using particle image velocimetry (PIV), and particle kinematics are calculated from images obtained with a high-speed camera in an overlapping field-of-view.

Numerous problems in scientific and engineering fields involve understanding the kinematics of particles in turbulent flows, such as contaminants, marine ...

Method Development for Contactless Resonant Cavity Dielectric Spectroscopic Studies of Cellulosic Paper

The current analytical techniques for characterizing printing and graphic arts substrates are largely ex situ and destructive. This limits the amount of data that can be obtained from an individual sample and renders it difficult to produce statistically relevant data for unique and rare materials. Resonant cavity dielectric spectroscopy is a non-destructive, contactless technique which can simultaneously interrogate both sides of a sheeted material and provide measurements which are suitable for statistical interpretations. This offers analysts the ability to quickly discriminate between sheeted materials based on composition and storage history. In this methodology article, we demonstrate how contactless resonant cavity dielectric spectroscopy may be used to differentiate between paper analytes of varying fiber species compositions, to determine the relative age of the paper, and to detect and quantify the amount of post-consumer waste (PCW) recycled fiber content in manufactured office paper.

A protocol for the non-destructive analysis of the fiber content and relative age of paper.

비접촉식 공진성 유전체 분광연구용 셀룰로오스 종이 공진법 개발

The current analytical techniques for characterizing printing and graphic arts substrates are largely ex situ and destructive. This limits the amount of ...

Fabrication of Nanoheight Channels Incorporating Surface Acoustic Wave Actuation via Lithium Niobate for Acoustic Nanofluidics

Controlled nanoscale manipulation of fluids is known to be exceptionally difficult due to the dominance of surface and viscous forces. Megahertz-order surface acoustic wave (SAW) devices generate tremendous acceleration on their surface, up to 108 m/s2, in turn responsible for many of the observed effects that have come to define acoustofluidics: acoustic streaming and acoustic radiation forces. These effects have been used for particle, cell, and fluid manipulation at the microscale, although more recently SAW has been used to produce similar phenomena at the nanoscale through an entirely different set of mechanisms. Controllable nanoscale fluid manipulation offers a broad range of opportunities in ultrafast fluid pumping and biomacromolecule dynamics useful for physical and biological applications. Here, we demonstrate nanoscale-height channel fabrication via room-temperature lithium niobate (LN) bonding integrated with a SAW device. We describe the entire experimental process including nano-height channel fabrication via dry etching, plasma-activated bonding on lithium niobate, the appropriate optical setup for subsequent imaging, and SAW actuation. We show representative results for fluid capillary filling and fluid draining in a nanoscale channel induced by SAW. This procedure offers a practical protocol for nanoscale channel fabrication and integration with SAW devices useful to build upon for future nanofluidics applications.

We demonstrate fabrication of nanoheight channels with the integration of surface acoustic wave actuation devices upon lithium niobate for acoustic nanofluidics via liftoff photolithography, nano-depth reactive ion etching, and room-temperature plasma surface-activated multilayer bonding of single-crystal lithium niobate, a process similarly useful for bonding lithium niobate to oxides.

음향 나노 유체학용 리튬 니오바테를 통한 표면 음향파 작동을 통합한 나노높이 채널 제조

Controlled nanoscale manipulation of fluids is known to be exceptionally difficult due to the dominance of surface and viscous forces. Megahertz-order ...

In Situ Surface Temperature Measurement in a Conveyor Belt Furnace via Inline Infrared Thermography

Measuring the surface temperature of objects that are processed in conveyor belt furnaces is an important tool in process control and quality assurance. Currently, the surface temperature of objects processed in conveyor belt furnaces is typically measured via thermocouples. However, infrared (IR) thermography presents multiple advantages compared to thermocouple measurements, as it is a contactless, real-time, and spatially resolved method. Here, as a representative proof-of-concept example, an inline thermography system is successfully installed into an IR lamp powered solar firing furnace, which is used for the contact firing process of industrial Si solar cells. This protocol describes how to install an IR camera into a conveyor belt furnace, conduct a customer correction of a factory calibrated IR camera, and perform the evaluation of spatial surface temperature distribution on a target object.

This protocol describes how to install an infrared camera into a conveyor belt furnace, conduct a customer correction of a factory calibrated IR camera, and evaluate the spatial surface temperature distribution of an object of interest. The example objects are industrial silicon solar cells.

인라인 적외선 테르모그래피를 통한 컨베이어 벨트 용광로의 시투 표면 온도 측정

Measuring the surface temperature of objects that are processed in conveyor belt furnaces is an important tool in process control and quality assurance. ...

Microfluidic Fabrication Techniques for High-Pressure Testing of Microscale Supercritical CO2 Foam Transport in Fractured Unconventional Reservoirs

Pressure limitations of many microfluidic platforms have been a significant challenge in microfluidic experimental studies of fractured media. As a result, these platforms have not been fully exploited for direct observation of high-pressure transport in fractures. This work introduces microfluidic platforms that enable direct observation of multiphase flow in devices featuring surrogate permeable media and fractured systems. Such platforms provide a pathway to address important and timely questions such as those related to CO2 capture, utilization and storage. This work provides a detailed description of the fabrication techniques and an experimental setup that may serve to analyze the behavior of supercritical CO2 (scCO2) foam, its structure and stability. Such studies provide important insights regarding enhanced oil recovery processes and the role of hydraulic fractures in resource recovery from unconventional reservoirs. This work presents a comparative study of microfluidic devices developed using two different techniques: photolithography/wet-etching/thermal-bonding versus Selective Laser-induced Etching. Both techniques result in devices that are chemically and physically resistant and tolerant of high pressure and temperature conditions that correspond to subsurface systems of interest. Both techniques provide pathways to high-precision etched microchannels and capable lab-on-chip devices. Photolithography/wet-etching, however, enables fabrication of complex channel networks with complex geometries, which would be a challenging task for laser etching techniques. This work summarizes a step-by-step photolithography, wet-etching and glass thermal-bonding protocol and, presents representative observations of foam transport with relevance to oil recovery from unconventional tight and shale formations. Finally, this work describes the use of a high-resolution monochromatic sensor to observe scCO2 foam behavior where the entirety of the permeable medium is observed simultaneously while preserving the resolution needed to resolve features as small as 10 &#181;m.

Microfluidic Fabrication Techniques for High-Pressure Testing of Microscale Supercritical CO2 Foam Transport in Fractured Unconventional Reservoirs

This paper describes a protocol along with a comparative study of two microfluidic fabrication techniques, namely photolithography/wet-etching/thermal-bonding and Selective Laser-induced Etching (SLE), that are suitable for high-pressure conditions. These techniques constitute enabling platforms for direct observation of fluid flow in surrogate permeable media and fractured systems under reservoir conditions.

골절된 비전통적인 저수지에서 마이크로스케일 초임계 CO2 폼 수송의 고압 테스트를 위한 미세 유체 제조 기술

Pressure limitations of many microfluidic platforms have been a significant challenge in microfluidic experimental studies of fractured media. As a ...