芯片实验室的制备技术

阐述了芯片实验室的材料、微细加工、流体驱动等制备技术的近期研究进展。系统介绍了芯片实验室的各种制备技术,这些技术包括紫外光刻、软刻蚀、LIGA技术、DEM技术、键合等。流体驱动是芯片实验室的动力,对多种新颖的流体驱动设计进行了对比,这些设计包括压力驱动、电渗驱动、电水力驱动、表面张力驱动、离心力驱动等。     

Time-resolved fluorescence detection of mosaic DNA chip

We demonstrated a time-resolved fluorescence (TRF) label and detection of mosaic DNA chip in this paper. We synthesized oligonucleotide sequences in situ on glass slides directly, and then sliced them up into small pieces and patched up the pieces bearing different sequences to generate a mosaic DNA chip. With multiple 4, 7-bis(chlorosulfophenyl)-1, 10-phenanthroline-2, 9-dicarboxylic acid (BCPDA, abbreviated as BCPDA) labeling method based on avidin-biotin amplification, we established a TRF detection format on the mosaic DNA chip. The detection method allows discriminatory signals for perfect match, one-base mismatch, two-base mismatch, and three-base mismatch by TRF labeled DNA hybridization, whereby Europium (III, Eu3+) was captured and released on the principle of complexation and dissociation interaction between BCPDA and Eu3+ solution when the BCPDA-tagged avidin and biotin-capped oligonucleotide sequence linked. The fluorescence spectra and related lifetimes were determined. We also compared the TRF detection mode with the conventional fluorescence one. These results showed the former is a potential alternative replacement of the latter, especially for labeling the mosaic DNA chip. The discovery is of fundamental interest and has significant implications to biochips and biosensors based on time-resolved-fluorescence detection.     

Thermal stress analysis and design optimization of direct chip attach (DCA) and chip scale package (CSP) in flip chip technology

Underfill encapsulation is a technique used to reinforce the solder bumps between the chip and the substrate in flip chip technology. To determine the optimal geometrical parameters and material properties for the package and candidate underfill materials is an important strategy for improving the thermo-mechanical reliability of flip chip packages. In this study, a stress-function-based energy method was developed to evaluate the interfacial peel and shear stress distributions in multilayered packaging structures. The stress functions were expressed in terms of sine and cosine trigonometric series. Simple programming and short CPU time lead to accurate stress distributions. After comparisons with other proposed numerical methods and results, the developed model was then coupled with a Genetic Algorithm to optimize the design of the direct chip attach (DCA) and chip scale package (CSP) in order to diminish the interfacial stresses and the possibility of crack initiation. The results revealed that the maximum peel and shear stress values were productively decreased and their peaks moved toward the center after conducting the optimizations in both cases. Improved geometrical and material parameters of the flip chip package were determined.     

Engineering DNA quadruplexes in DNA nanostructures for biosensor construction

DNA quadruplexes are nucleic acid conformations comprised of four strands.They are prevalent in human genomes and increasing efforts are being directed toward t...     

A MutS-based protein chip for detection of DNA mutations

This paper describes a new protein chip method for detection of single-base mismatches and unpaired bases of DNA, using a genetic fusion molecular system Trx-His6-Linker peptide-Strep-tagII-Linker peptide-MutS (THLSLM). The THLSLM coding sequence was constructed by attaching Strep-tag II and mutS gene to pET32a (+) sequentially with insertion of a linker peptide coding sequence before and behind Strep-tagII gene, respectively. THLSLM was expressed in E. coli AD494 (DE3) and purified using Ni(2+)-chelation affinity resin. THLSLM retained both mismatch recognition activity and streptavidin binding affinity. THLSLM was then immobilized on the chip matrix coated with streptavidin through the Strep-tag II-streptavidin binding reaction. The resulting protein chip was used to detect the mismatched and unpaired mutations in the synthesized oligonucleotides, as well as a single-base mutation in rpoB gene from Mycobacterium tuberculosis, with high specificity. The method could potentially serve as a platform to develop the high-throughput technology for screening and analysis of genetic mutations.     

Dynamic DNA hybridization on a chip using paramagnetic beads

Dynamic DNA hybridization is presented as an approach to perform gene expression analysis. The method is advantageous because of its dynamic supplies of both DNA samples and probes. The approach was demonstrated on a microfluidic platform by incorporating paramagnetic beads as a transportable solid support. A glass chip was fabricated to allow simultaneous interrogation of eight DNA target samples by DNA probes. DNA targets were immobilized on beads via streptavidin-biotin conjugation or base pairing between oligonucleotide residues. The DNA/bead complex was introduced into the device in which hybridization took place with a complementary probe. The hybridized probe was then removed by heat denaturation to allow the DNA sample to be interrogated again by another probe with a different sequence of interest. A pneumatic pumping apparatus was constructed to transport DNA probes and other reagents into the microfluidic device while hydrostatic pumping was used for the introduction of paramagnetic beads with samples. After investigating three types of paramagnetic beads, we found Dynabeads Oligo(dT)25 best suited this application. Targets on the beads could be sequentially interrogated by probes for 12 times, and the hybridization signal was maintained within experimental variation. Demonstration of specific hybridization reactions in an array format was achieved using four synthesized DNA targets in duplicate and five probes in sequence, indicating the potential application of this approach to gene expression analysis.     

用于批量快速筛选最佳低温保存程序的生物芯片技术

低温生物学应用中,筛选最佳的冻结、复温程序以及相应的保护剂配方,通常需要大量繁琐、费时且高度重复性的测试工作.将样品准备及其活性检测功能加以集成,首次在低温保存程序优化方面引入了生物芯片技术的概念.设计制作了相应的原型器件并开展实验研究.结果表明,流道式芯片用于样品分配时效果不佳,而点样式芯片则可实现快速、可靠的样品加载,红外实验进一步表明其传热一致性较好.在此基础上,利用点样式芯片与集成化的半导体制冷器件相结合,对多种生物样品的低温冷冻及复温效果进行了测试,基于对结果的比较分析可以筛选出最优的降温、复温程序及低温保护剂浓度配比.此外,还对批量测定低温保护剂溶液的热物性也进行了考察.研究表明,借助于功能集成化及检测自动化的生物芯片,可以实现大规模快速优化复杂低温保存程序.     

Electrokinetically controlled DNA hybridization microfluidic chip enabling rapid target analysis

Biosensors and more specifically biochips exploit the interactions between a target analyte and an immobilized biological recognition element to produce a measurable signal. Systems based on surface nucleic acid hybridization, such as microarrays, are particularly attractive due to the high degree of selectivity in the binding interactions. One of the drawbacks of this reaction is the relatively long time required for complete hybridization to occur, which is often the result of diffusion-limited reaction kinetics. In this work, an electrokinetically controlled DNA hybridization microfluidic chip will be introduced. The electrokinetic delivery technique provides the ability to dispense controlled samples of nanoliter volumes directly to the hybridization array (thereby increasing the reaction rate) and rapidly remove nonspecific adsorption, enabling the hybridization, washing, and scanning procedures to be conducted simultaneously. The result is that all processes from sample dispensing to hybridization detection can be completed in as little as 5 min. The chip also demonstrates an efficient hybridization scheme in which the probe saturation level is reached very rapidly as the targets are transported over the immobilized probe site enabling quantitative analysis of the sample concentration. Detection levels as low as 50 pM have been recorded using an epifluorescence microscope.     

浅谈DNA防伪技术

随着市场经济的深入发展,人们的物质生活得到了极大的丰富,但是当人们充分享受生活的同时,也被市场上大量假冒伪劣产品所困扰。为了保护消费者的权益和商家的经济利益,各种防伪技术应运而生,DNA防伪技术便是其中的一种。本文主要从原理、特点、产品种类、应用及前景等方面来介绍DNA防伪这种高科技生物技术。     

Intelligent construction technology of railway engineering in China

Intelligent construction technology has been widely used in the field of railway engineering. This work first analyzes the connotation, function, and characteristics of intelligent construction of railway engineering (ICRE) and establishes its system structure from three dimensions, namely, life cycle, layers of management, and intelligent function, to deeply understand the development situation of intelligent railway construction in China. Second, seven key technical support systems of ICRE, which include building information modeling (BIM) standard system for China’s railway sector, technology management platform and life cycle management based on BIM+GIS (geography information system), ubiquitous intelligent perception system, intelligent Internet-of-Things (IoT) commu-nication system based on mobile interconnection, construction management platform based on cloud computing and big data, unmanned operation system based on artificial intelligence, intelligent machinery and robot, and intelligent operation and maintenance system based on BIM and PHM (prediction and health management), are established. Third, ICRE is divided into three development stages: primary (perception), intermediate (substitution), and advanced (intelligence). The evaluation index system of each stage is provided from the aspects of technology and function. Finally, this work summarizes and analyzes the application situation of ICRE in the entire railway sector of China, represented by Beijing–Zhangjiakou and Beijing–Xiong’an high-speed railways. Result shows that the technical support systems of the ICRE have emerged in China and are still in the process of deepening basic technology research and preliminary application. In the future, the ICRE of China’s railway sector will develop toward a higher stage.     

高寒地区混凝土井塔快速施工关键技术的研究

在西北高寒地区钢筋混凝土井塔施工中,通过对桩基范围人工冻土的快速解冻技术和高寒地区冬期井塔快速施工成套技术的研究应用,确保了工程质量,加快了井塔桩基和冬期井塔主体的施工速度,缩短了井塔施工工期,解决了高寒地区煤矿建设周期长的施工技术瓶颈问题。     

水下交通隧道的设计与施工

综合论述了水下隧道在穿越江河湖海时所有的优势,介绍了水下交通隧道的设计与施工概况,讨论了水下隧道勘察设计、施工的几项关键技术,详细介绍了水下隧道施工的常用方法.     

斜坡海涂上修建海堤的爆炸挤淤施工技术

采用爆炸挤淤置换法在较陡的斜坡海涂上修筑海堤,因堤身内外侧涂面高差大,施工过程中抛填堤身容易滑塌。最初在浙江舟山某海堤工程中遇到了这个难题。通过对堤身稳定性的计算分析,将堤身抛填方法调整为内侧突前、外侧迟后,炸药布置侧重于内侧。既保证了施工期抛填堤身的稳定,又使得爆炸处理后形成的堤身断面满足设计要求。此后该方法又在多条类似海堤的施工中得到成功的应用,由此总结出了在斜坡海涂上修建海堤的爆炸挤淤技术,并申报了发明专利(201510908384.1)。     

斜坡海涂上修建海堤的爆炸挤淤施工技术

采用爆炸挤淤置换法在较陡的斜坡海涂上修筑海堤,因堤身内外侧涂面高差大,施工过程中抛填堤身容易滑塌。最初在浙江舟山某海堤工程中遇到了这个难题。通过对堤身稳定性的计算分析,将堤身抛填方法调整为"内侧突前、外侧迟后",炸药布置侧重于内侧。既保证了施工期抛填堤身的稳定,又使得爆炸处理后形成的堤身断面满足设计要求。此后该方法又在多条类似海堤的施工中得到成功的应用,由此总结出了在斜坡海涂上修建海堤的爆炸挤淤技术,并申报了发明专利(201510908384.1)。     

厦门翔安海底隧道修建技术初论

对厦门翔安海底隧道从桥梁隧道方案比选到跨海隧道方案的确定进行研究.介绍了在此作海底隧道方案的优越性,以及该海底隧道的特点、难点和施工技术方案,并对隧道设计、施工中所存在的不足之处进行论述.     

The role of particle technology in developing sustainable construction materials

This paper presents a brief review of the role of particle technology in the development of low-CO₂ aluminosilicate ‘geopolymer’ binders and concretes as an alternative to traditional Portland cement-based materials. The role of particle shape in particular is highlighted, both in the context of its effect on paste rheology and on water demand. The spherical particles of fly ash and the platy particles of metakaolin show opposite effects in each of these areas, and this must be understood and controlled if an effective geopolymer concrete is to be designed. The angular particles of blast furnace slag are also important in determining paste rheology and porosity. The selection of the correct combination of aggregate gradings is critical in maximising concrete durability, as the ability of aggregates to pack sufficiently densely in a hardened concrete product then hinders the ability of aggressive external agents to migrate into the concrete and cause structural damage to either the binder or the embedded steel reinforcing.     

Electrochemical assay of nonlabeled DNA chip and SNOM imaging by using streptavidin-biotin interaction

The assay of DNA biosensor-based nucleic acid recognition using microfabrication technology provides for high sensitivity, good surface coverage and reproducibility. We have achieved efficient immobilization and hybridization of nonlabeled DNA using cyclic voltammetry (CV), square wave voltammetry (SWV) and scanning near-field optical microscopy (SNOM) techniques. The increased electrochemical response observed following the immobilization of biotinlyated ssDNA probe suggests that nucleic acid is a somewhat better medium for electronic transfer. We demonstrated the high coverage of immobilized FITC-labeled biotinylated DNA probe on a streptavidin-modified surface using SNOM imaging. SNOM imaging of FITC-labeled complementary DNA also exhibited fluorescent light spots of hybridization distributed throughout. No fluorescent light was observed with the hybridization of non-complementary DNA.     

Affordable housing and clean technology transfer in construction firms in Brazil

The affordable housing deficit in Brazil is 5.6 million homes. The Main Brazilian housing government program was called “Minha Casa, Minha Vida” from 2009 to 2020. It had little progress in the housing sustainability requirements in the last ten years. For that reason, construction industry has very little changed in terms of innovation. However, this sector has maintained standard production on a large scale. So, the crucial change could become from companies. The clean technology transfer is limited in the Brazilian affordable housing firms. One solution is to analyse this transfer process like a network. Then, it will be possible to evaluate the technological adaptability of these kinds of construction firms. This research aimed to estimate the clean technology transfer between construction firms in Brazil dedicated to building affordable housing. For this, it was identified the 69 construction firms in five cities of Rio Grande do Sul. The cities were Canoas, Caxias do Sul, Passo Fundo, Pelotas, Porto Alegre. Then, a network analysis identified the degree, betweenness, closeness, and density. These studies identify poor performance versus sustainability needs of current low-cost construction. As a result, it identifies the technology transfer capabilities that allow medium-term gains for Brazilian construction firms. Finally, we developed technology transfer indicators to understand the complexity of affordable housing production in Brazil.     

立井井塔建安工程综合施工新技术

以龙固煤矿1#主井提升系统施工为例,介绍了井塔建筑和井筒装备、提升机等设备安装工程平行作业的施工组织特点以及立井井塔滑模施工、井筒装备采用6层吊盘一次成井安装和永久提升机安装的施工技术,为同类型工程施工提供了一种可借鉴的综合施工应用技术。