基于BioMEMS技术的DNA芯片研究

近年来基于微电子机械系统 (MEMS)技术研究和开发的一个新领域就是BioMEMS ,特别是对生物芯片和生物化学微分析系统的研究。文中叙述了基于BioMEMS技术的DNA芯片研究 ,介绍了几种不同结构的DNA芯片 ,以及DNA PCR扩增器芯片、DNA CE毛细管电泳芯片、微流动控制器件和实验室芯片 (LabonaChip)等。还报告了作者们成功采用MEMS技术 ,研制成集成化微结构型PCR DNA扩增芯片 ,芯片上包括有加热器、温度传感器、2 μL容积的反应池以及输入输出通道 ;能实现快速扩增 ,最快加热速度为 15℃ s ,降温速度为 10℃ s。研制成Si—玻璃 ,玻璃—玻璃和玻璃—PDMS三种结构的毛细管电泳芯片 ,沟道宽 2 0 0 μm ,深 2 0 0 μm。研制成一种表面等离子体谐振 (SPR)生化分析系统 ,其入射光扫描角范围从 40°到 70° ,分辨率 0 .1%度 ,可测折射率范围 1.0 4～ 1.47。     

基于荧光显微镜的毛细管电泳系统的构建

毛细管电泳仪具有灵敏度高、分析速度快等优势,为降低其生产成本,基于电泳原理,以荧光显微镜为基础,设计了一套毛细管电泳系统。以20 bp(base pairs,碱基对)DNA ladder和100 bp DNA ladder为样本,全面分析了系统的稳定性、灵敏度和分离效果。结果表明:该系统在9 min内可以实现1500 bp以内DNA片段的高效分离,系统检测极限为0.1 ng/μL;在优化的电泳条件下,对限制性内切酶φX174-HincⅡ作用过的λ-DNA片段5 min内实现了291 bp与297 bp DNA片段的区分。     

一种集成PCR反应室与CE的生物芯片的研究

生物芯片是便携式生物化学分析器的核心技术.主要研究内容是研制一种集成了聚合酶链式反应PCR(Polymerase Chain Reaction)反应室与毛细管电泳CE(Capillary Electrophoresis)的生物芯片,它的用途有DNA测序,DNA突变检测等,另外还可以改制成便携生物传感器,通过与现有的实验数据的对照分析可以快速检测并识别不明微生物,便于及时采取针对措施.     

一种低温供暖自然对流散热器的换热特性及结构的研究

我国的低温热源资源非常丰富,但由于部分低温热源的温度较低,利用率不高,造成了一定的浪费。毛细管自然对流散热器是一种新型的低温供暖末端设备,以毛细管网为换热芯,以自然对流为主要散热方式,可使用不低于30℃的热水采暖,从而对其他类型供暖末端设备难以利用的低品位热源加以循环利用。本文利用数值模拟的方法,分析了毛细管自然对流散热器的散热规律,得出了设备高度、厚度、进风口和送风口尺寸等几个结构因素与设备散热强度的制约关系,并根据关系曲线和数据总结出了最优结构因素的计算公式,为毛细管自然对流散热器的进一步研究和应用提供了依据。为保证结果的可信性,本文还通过相应样机的散热量试验结果和温度场实测数据对模拟结果进行验证,结果表明模拟计算结果正确。     

21世纪毛细管电泳在刑侦分析中的应用

介绍了毛细管电泳的分离机理和方法分类;评述了2000～2009年毛细管电泳法在刑侦分析中的应用,重点是在DNA分析方面的应用;对未来发展做了讨论,引用文献49篇。     

毛细管电泳的进展

在本综述中简要地介绍了毛细管电泳的发展,毛细管电泳的仪器,微型电泳仪,毛细管电泳检测器,毛细管电色谱,毛细管电泳柱,毛细管电泳的应用和毛细管电泳的手性分离。     

DNA测序电泳荧光信号的小波去噪分析

在DNA荧光测序中,噪声影响分析的准确度和检出限。相比其他滤波方法,小波分析具有良好的时频域分辨特性。在小波去噪处理中,正确选择合适的小波基函数和去噪阈值直接关系到信号去噪处理的质量。通过对毛细管电泳(CE)荧光信号的仿真分析,结果表明:选择sym7小波基函数、分解层数(lev=5)与使用软阈值,可以有效去除CE荧光光谱信号的噪声,提高分析准确度。将其用于处理实际的DNA电泳荧光信号,效果良好。     

毛细管电泳的进展

在本综述中简要地介绍了毛细管电泳的发展，毛细管电泳的仪器，微型电泳仪，毛细管电泳检测器，毛细管电色谱，毛细管电泳柱，毛细管电泳的应用和毛细管电泳的手性分离。     

便携式PCR-CE微流体芯片分析仪控制系统设计

本文设计并开发出用于DNA聚合酶链式反应（PCR）和毛细管电泳（CE）分离的微流体芯片分析仪控制系统.本系统采用32位嵌入式微控制器ARM实现PCR扩增所需的3条恒温区的闭环温度控制和毛细管电泳分离功能所需的高压电场自动控制.由于对恒温区温度的精确控制是影响PCR反应的关键因素,因此温度控制系统采用模糊免疫PID算法实现对温度的精确控制,其控制性能优于常规PID控制器.本仪器还包括矩阵式键盘、小型液晶显示屏、串行通信模块和毛细管电泳分离模块.实验结果表明本系统不但完全满足设计要求,而且PCR温度控制更加精确,分析软件功能全面,系统体积小,便于室外使用.     

毛细管电泳法检测化妆品中对羟基苯甲酸酯类防腐剂

采用毛细管区带电泳法同时测定化妆品中4种对羟基苯甲酸酯类防腐剂。色谱条件是:75 μm× 57 cm(有效长度50 cm)毛细管,电解质为25 mmol/L硼砂(pH 10.0)缓冲溶液,分离电压20kV,温度25℃,0.5 psi进样5s,检测波长200 nm。对羟基苯甲酸甲酯、对羟基苯甲酸乙酯、对羟基苯甲酸丙酯、对羟基苯甲酸丁酯在10 min内基线分离,10～500 μg/mL范围内线性关系良好(r>0.9949),检出限为0.60～1.20 μg/mL,样品加标回收率为75.5%～112.0%。     

磁场强化磁性液体自然对流传热的实验测量

磁场能强化磁性液体的自然对流传热。为了准确测量磁场对磁性液体强化自然对流传热的贡献,设计制作了一个由均匀磁场和均匀梯度磁场矢量叠加合成的新磁场。在恒定温度梯度下,新磁场使磁性液体各处密度变化均等,各处自然对流传热变化均等。从而比较准确地测量了磁场引起的磁性液体自然对流传热系数的变化,为深入研究磁场强化磁性液体自然对流传热的效应提供了比较准确的测量手段。     

Natural convection between concentric spheres in electromagnetic fields

This study performs numerical analyses for two different working fluids. One is an analysis of natural convection using a model with air that is compared with the results of applied experiments. Then, it can be used to investigate the pattern of natural convection in concentric spheres. The other is an investigation for the relationship between velocity field, electromagnetic field, and temperature field in a model with molten metal. The subject of the analysis model is the natural convection between two concentric spherical shells. In particular, a process where induced magnetic fields intensify the imposed magnetic field can be called a dynamo process. This study uses a modified B method in order to investigate the role of this induced magnetic field. This method is also compared to a ϕ method that only considers imposed magnetic fields. In addition, this study examines the relationship between the velocity field and the electromagnetic field for the velocity field through applying Coriolis forces.     

高深宽比微细结构电铸时传质过程数值分析

针对高深宽比微细结构电铸时存在严重传质受限的问题,以微深槽特征为分析对象建立液相传质两种数学模型——维扩散模型和二维对流—扩散模型,并分别用Matlab专用工具箱和Fluent 6.2流体仿真软件进行数值求解,依次分析以扩散、强制对流－扩散、复合对流(强制对流和自然对流)－扩散等为主导传质模式作用下微细电铸时,流场和离子浓度场的空间变化规律及其对液相传质效果的影响,并进行试验验证。结果表明：微细结构电铸时,单一扩散作用仅能用于深宽比小于2且电流密度小于2 A/dm2的液相传质场合;槽外强制对流只能对深宽比小于2的微槽内电解液产生一定搅拌作用;强化槽内自然对流作用并与槽外强制对流协同配合时,槽(深宽比为5)内可形成独特的单个或多个占据整个槽空间的涡流循环胞,涡流流速约为强制对流流速的1/20～1/2,明显改善传质效果,试验结果与此相印证。     

Design and operation of a portable scanner for high performance microchip capillary array electrophoresis

We have developed a compact, laser-induced fluorescence detection scanner, the multichannel capillary array electrophoresis portable scanner (McCAEPs) as a platform for electrophoretic detection and control of high-throughput, integrated microfluidic devices for genetic and other analyses. The instrument contains a confocal optical system with a rotary objective for detecting four different fluorescence signals, a pneumatic system consisting of two pressure/vacuum pumps and 28 individual addressable solenoid valves for control of on-chip microvalves and micropumps, four Polymerase Chain Reaction (PCR) temperature control systems, and four high voltage power supplies for electrophoresis. The detection limit of the instrument is ~20 pM for on-chip capillary electrophoresis of fluorescein dyes. To demonstrate the system performance for forensic short tandem repeat (STR) analysis, two experiments were conducted: (i) electrophoretic separation and detection of STR samples on a 96-lane microfabricated capillary array electrophoresis microchip. Fully resolved PowerPlex(?) 16 STR profiles amplified from 1 ng of 9947A female standard DNA were successfully obtained; (ii) nine-plex STR amplification, sample injection, separation, and fluorescence detection of 100-copy 9948 male standard DNA in a single integrated PCR- capillary electrophoresis microchip. These results demonstrate that the McCAEPs can be used as a versatile control and detection instrument that operates integrated microfluidic devices for high-performance forensic human identification.     

大直径高质量太阳能级硅单晶磁场直拉技术研究

直拉法易于制备大直径单晶,但在其拉制过程中,晶体生长系统中的熔体会产生自然对流、毛细对流以及强迫对流。在上述三种熔体对流的相互作用下,会使晶体中的氧、碳等杂质产生不均匀分布而影响晶体质量。通过在熔体空间中引入磁场可以有效抑制熔体各种对流,应用于硅单晶生长系统的磁场有横向磁场、纵向磁场和勾形磁场,其中勾形磁场在控制大直径硅单晶中的氧等杂质的含量以及径向分布均匀性方面效果较好。     

荧光标记DNA分子量内标的设计与制备

目的:设计并制备65bp-500bp范围的荧光标记DNA分子量内标。方法:p MD18-T Vector连接任意一段割胶回收的DNA片段,克隆后提取重组质粒经双酶切后作为模板,在其上游设计一条固定引物并用荧光标记,在其下游设计一系列引物,经PCR扩增后在ABI 3100遗传分析仪上检测。结果:扩增产物DNA片段大小分别为65bp、105bp、149bp、200bp、241bp、269bp、311bp、345bp、400bp、450bp、500bp,与预期片段大小一致。结论:11个片段经混合调平后,峰型良好,出峰位置均匀,可用于毛细管电泳中DNA片段大小的确定。     

Utilization of honeycomb structures for a flat-plate solar collector by reduction of natural convection heat loss

A most common and economical way of utilizing solar energy is to use a flatplate collector to capture incoming solar energy by heating either liquids or gases. Therefore, a solar collector should be the most critical part of the performance necessary for the system, since maximum available heat depends solely on the collector. In the present investigation, considering that most heat loss from solar collectors results from the natural convection between an absorber plate and a coverglass,it has been demonstrated that this natural convection can be suppressed and heat performances of a solar collector are enhanced by placing thin and poorly conducting honeycomb material between an absorber plate and a coverglass. By suppressing natural convection within collector spacing it has been shown experimentally that honeycomb structures effectively raise critical Rayleigh number, since they provide more shear surfaces.     

Effect of thermal radiation on convection heat transfer in cooling channel of photovoltaic thermal system

The effect of thermal radiation on convection heat transfer in flat-box type cooling channel of photovoltaic thermal system with tilt angle of 30 degree was studied by 3D numerical simulation under constant heat flux boundary condition. The temperature contours and velocity fields of fluid near the outlet were obtained. The variations of wall temperature and convection Nusselt number along flow direction for all the separate walls composing the cooling channel were compared and analyzed. The results show that due to thermal radiation, the deflection of the maximum velocity region to heated top wall, together with the asymmetry of temperature field is weakened. For natural convection, radiation promotes the formation of multi-vortices. For mixed convection, heat transfer on all the cooling channel walls is enhanced under the condition of lower heat flux while heat transfer on heated top wall is deteriorated when the heat flux is relative high. Also, pressure re-rising is promoted by thermal radiation.     

Pressure drop and flow distribution characteristics of single and parallel serpentine flow fields for polymer electrolyte membrane fuel cells

This study numerically investigates pressure drop and flow distribution characteristics of serpentine flow fields (SFFs) that are designed for polymer electrolyte membrane fuel cells, which consider the Poiseuille flow with secondary pressure drop in the gas channel (GC) and the Darcy flow in the porous gas diffusion layer (GDL). The numerical results for a conventional SFF agreed well with those obtained via computational fluid dynamics simulations, thus proving the validity of the present flow network model. This model is employed to characterize various single and parallel SFFs, including multi-pass serpentine flow fields (MPSFFs). Findings reveal that under-rib convection (convective flow through GDL under an interconnector rib) is an important transport process for conventional SFFs, with its intensity being significantly enhanced as GDL permeability increases. The results also indicate that under-rib convection can be significantly improved by employing MPSFFs as the reactant flow field, because of the closely interlaced structure of GC regions that have different path-lengths from the inlet. However, reactant flow rate through GCs proportionally decreases as under-rib convection intensity increases, suggesting that proper optimization is required between the flow velocity in GCs and the under-rib convection intensity in GDLs.