Developments and Applications of Paper-based Microfluidics

纸芯片微流控技术是一种新型微流控技术。相比于以玻璃、石英、高聚物等为基底的传统微流控芯片,纸芯片具有成本低、易操作、可携带、耗样量小等优点。该文介绍了纸芯片的发展及常用的制作方法,并举例说明了光度法、荧光法、化学发光及电化学发光法和电化学法在纸芯片检测中的应用;归纳了纸芯片技术在临床诊断、环境监控以及食品安全分析等方面的应用;最后对纸芯片微流控的应用前景进行了展望。Paper-based microfluidics stand out as a new class of microfluidic technology,and present distinguishing features such as low cost,ease of use,portability,and low reagent consumption compared with the conventional microfluidic devices.In this paper,the development of μPADs was first introduced,and the common fabrication techniques were presented.Then the methods for quantitative analysis on μPADs were summarized including colorimetry,fluorescence,chemiluminescence,electrochemiluminescence and electrochemistry with their applications in clinical diagnostics,environmental monitoring as well as food quality control.Finally,the potential and future outlooks ofμPADs were discussed.国家重点基础研究发展计划项目(2010CB732402;2013CB933703); 国家自然科学基金项目(91313302;21205100;21275122); 国家杰出青年科学基金项目(21325522

Investigation on the Optical Properities of GaAsN

III-V族化合物半导体是制造固体发光器件的重要材料。GaAsN作为一种新型的掺氮III-V发光材料，由于在远红外到紫外波长范围的光电子器件有广泛的应用前景而倍受人们的关注。GaAsN有着特殊的光电性质，它的带隙宽度不是GaAs和GaN的线性内插关系，而是存在着巨大的带隙弯曲，因此又被称为“反常”混晶。 本文第一章主要回顾了近几十年来对GaAs:N等电子杂质体系的研究历史，介绍了GaAs:N的发光特性以及等电子束缚激子形成的机制等问题。第二章讨论了光致发光谱的理论知识，包括半导体带间光跃迁基本理论、激子复合发光、束缚激子辐射复合发光光谱以及在材料检测中的应用。 第三章测试了GaAs1-xN...III-V compound semiconductors are important materials for photoelectric devices. As a novel III-V-N material, GaAsN has been intensively studied for the past decade. The incorporation of small amounts of N leads to a giant band-structure change in the host semiconductor GaAs, so it is called as abnormal alloy. However, the mechanism underlying the N-induced band-gap reduction remains contentious. ...学位：理学硕士院系专业：物理与机电工程学院物理学系_凝聚态物理学号：20012400

Raman Study on GaAs_(1-x)N_x Alloys

【中文文摘】室温下采用背散射几何配置,在近共振条件下测量GaAs1-xNx混晶的喇曼散射谱.由于N原子的引入,导致类GaAs的LO1、TO1声子和类GaN的LO2声子线宽变大,禁戒的TO1声子变为喇曼活性;随着N组分的增加,TO1声子强度增大、LO1声子有红移的趋势、LO2声子有蓝移的趋势,根据它们随N组分x移动的速度推断出样品不存在应变效应.另外还讨论了布里渊区边界声子LA(L)与LO(L)、二级喇曼散射谱声子LO2、LO1+LA1(L)以及2LO1随N组分x增大的变化趋势. 【英文文摘】Near-resonant back-scattering Raman studies of GaAs_(1-x)N_x(x=0.1%～1.7%)alloys at room temperature are reported.The Raman spectra exhibits two-mode behavior.With the N incorporation,the full widths at half maximum (FWHM)of GaAs-like LO_1 mode and TO_1 mode are broader than those of the pure GaAs.The forbidden TO_1 mode is activated and its intensity is enhanced with increasing the N content, while the ratio of I_(TO1)/I_(LO1) remains constant.The red-shift of the LO_1 mode is smaller and the blue-shift of the GaNlike LO2 mode is larger than those reported in previous studies ,which indicate that the alloying effect instead of the strain effect exists in the alloys. The trends of LA( L ) 、LO( L ) 、LO2 、LO1 + LA1 ( L ) 、2LO1 phonons with increasing the N composition are also disscussed. These trends are attributed to the breakdown in the zinc blende国家自然科学基金(60276002);; 福建省自然科学基金(A0110007)资

Investigation on the Emission Recombination Mechanism of GaP_(1-x)N_(x) Alloys(x=0.24% ～3.1%)

【中文文摘】利用变温光致发光(PL)谱研究了一系列GaP1-xNx混晶的发光复合机制.GaP1-xNx混晶的PL谱从低组分的NN对束缚激子及其声子伴线到高组分杂质带发光的特征,表现出明显的带隙降低的趋势.测量结果显示,在组分x≥0.24%的样品的发光谱中NN1能量之下已经开始出现几个新的束缚态,在低组分的混晶中,只存在一种激活能,仍然保持有束缚激子的特征;而在高组分样品(x≥0.81%)中存在两种激活能.高组分样品一方面仍保留有束缚激子的特征,另一方面也表现出新的发光机制. 【英文文摘】This paper presented an investigation on the emission recombination mechanism of the novel GaP_(1-x)N_(x) alloys, using the temperature-dependent photoluminescence(PL) spectra. The GaP_(1-x)N_x alloys display obvious band-gap reduction characteristic, with the PL spectra developing from nitrogen bound excitons and their phonon replicas under low x composition to impurity band emission under high x composition. The results apparently indicate the appearance of several new bound states below the NN_1 bound exciton even when the composition x is as low as 0. 24 %. In low composition alloy , there is only one activation energy , which still remains the characteristic of bound exciton state. While in high composition alloy ( x ≥0. 81 %) , there exist two kinds of activation energies. The samples with high composition , on one hand , still remain the bound exciton characteristic , on the other hand , display new recombination mechanism. Such new recombination might be related to NNN cluster or have certain interaction with the NN bound excitons.国家自然科学基金(60276002); 福建省自然科学基金(A0110007)资

Fabrication of Large-Area Suspended MEMS Structures Using GaN-on-Si Platform

In this letter, piezosensitive elements featuring large-size suspended gallium nitride (GaN) microstructures are fabricated with a two-step dry-release technique using the GaN-on-Si platform. The suspended microstructures are integrated with highly piezosensitive AlGaN/GaN heterostructures as sensing units to realize the GaN-based integrated microsensors. To characterize the residual-stress distribution of the fabricated microstructures, micro-Raman spectroscopy is employed. A microaccelerometer structure with a 250 x 250-mu m(2) proof-mass area is fabricated with the proposed fabrication technique, and the piezoresponse properties of the integrated sensing elements are characterized through bending experiment

Study on the New Bound States in the GaP_(1-x)N_x Alloys

【中文文摘】利用变温光致发光(PL)谱及时间衰退发光谱研究了一系列CaP_(1-x)N_x混晶的光学性质。GaP_(1_x)N_x混晶的PL谱从低组分的NN对束缚激子及其声子伴线到高组分杂质带发光的特征,表现出明显的带降降低的趋势。测量结果显示,在组分x≥0.24％的样品的发光谱中NN_1能量之下已经开始出现几个新的束缚态,对其激活能的拟合及对时间衰退发光谱的分析表明,新的束缚态一方面仍保留有N束缚激子的性质,另一方面又表现出有别于NN对束缚激子的发光机制。说明新的束缚态有可能由新的N原子组成(如NNN原子)或与NN对束缚激子存在着某种相互作用。 【英文文摘】GaP_(1-x)N_x alloy is a remarkable and promising semiconductor for its giant band-gap bowing effect and its potential application in optoelectronic devices. In this article, we carried out a series of studies on the optical properties of GaP_(1-x)N_x alloys, especially focusing on the samples with composition x=0.24%, 0.6%, 0.81%, using temperature-dependent photoluminescence(PL) speetra and transient photoluminescense spectra. At 17 K PL spectra, the GaP_(1-x)N_x alloys exhibit an obvious tende...国家自然科学基金(60276002);福建省自然科学基金(A0110007

干旱内陆河灌区节水农业综合技术体系研究与集成

本课题从工程节水、农艺节水、管理节水三个方面,集成了农业高效节水、水肥盐调控、生态保护、监测与管理等关键技术,提出了干旱内陆河灌区农业节水技术集成体系与应用模式。提出了仅需根据水流推进过程确定土壤入渗参数和田面糙率系数的新方法,简化了地面灌溉设计。提出了根据土壤剖面含水率变化估算柽柳生长条件下潜水蒸发的理论方法与数学模型,为解决天然植被实际生态耗水问题提供了简易可行的方法