SnO_2/ZnO及ZnO/SnO_2双层膜的气敏性质

采用动态脉冲法研究了ＳｎＯ２／ＺｎＯ及ＺｎＯ／ＳｎＯ２ 双层膜的气敏性质。结果表明：选择合适的膜厚及膜厚比,可获得灵敏度及选择性良好的气敏元件。讨论了一些影响双层膜气敏性质的因素,结合元素的扩散,初步解释了膜厚与灵敏度的关系。     

ZnSnO3陶瓷材料气敏特性与导电机理

Ｘ－射线光电子光谱（ＸＰＳ）分析表明，在２５～３００℃时，ＺｎＳｎＯ３的表面存在及Ｏ￣－两种吸附氧，且随工作温度的增加，逐渐转变成Ｏ￣－或Ｏ￣（２－）。ＺｎＳｎＯ＿３周表面电阻控制型气敏材料，氧的吸附活化能为０．５２ｅＶ。ＺｎｓｎＯ＿３基元件对各种还原性气体都有一定气敏效应，它对乙醇比汽油的分辨率高５倍以上。     

表面气氛处理对气敏元件特性的影响

选择适当气体对气敏元件进行处理是气敏元件表面修饰的重要方法，本文利用ＳＯ２对Ｈ２Ｓ气敏元件进行了不同条件的处理，使得气敏元件的灵敏度和选择性得到了明显的改善。     

几种尖晶石型氧化物纳米粉体的制备及气敏性

采用化学共沉淀法合成了４种尖晶石型复合氧化物ＭＦｅ２Ｏ４（Ｍ＝Ｃｕ＾２＋，Ｚｎ＾２＋，Ｃｄ＾２＋，Ｍｇ＾２＋），Ｘ射线粉末衍射分析，透射电镜及比表面测定等表征结果表明它们均具较大比表面积的纳米粉体，平均粒径〈５０ｎｍ，将样品做成厚膜型气敏元件，测定了其对乙炔，液化石油气，一氧化碳、氢气和乙醇等还原（可燃）性气体的气敏特性。     

钐对不同氧空位SnO2气敏性能的影响

用Ｓｍ对不同氧空位浓度的ＳｎＯ２－ｘ气敏材料进行掺杂化学改性,并进行ＸＲＤ,ＸＰＳ,ＳＥＭ分析和比表面积测定,考察改性后的气敏材料对Ｃ６Ｈ６,Ｃ６Ｈ１２,Ｃ２Ｈ５ＯＨ,ＣＯ,Ｈ２等的气敏性能。     

纳米SnO2微粉的制备与性能

纳米ＳｎＯ_２微粉的制备与性能刘杏芹，陶善文，沈瑜生（中国科学技术大学材料科学与工程系合肥２３００２６）关键词纳米微粉，二氧化锡，溶胶－凝胶法，气敏性能ＳｎＯ２作为一种功能基体材料，在气敏、湿敏、光学技术等方面已有广泛的应用，而ＳｎＯ２微粉或超微粉的?..     

WO3基气敏传感器*

气敏传感器已在生物、化学、航空、军事等领域获得了广泛的应用。鉴于WO₃基气敏传感器是检测H₂S、NO_x、O₃和NH₃等气体最有前景的新型氧化物气敏传感器之一,本文以不同的敏感气体为分类依据系统阐述了近年来WO₃基气敏传感器的研究进展,详细探讨了制备方法及贵金属掺杂对上述各种气体气敏性能的影响,并指出了目前WO₃基气敏传感器在研究过程中存在的问题。     

CdO—SnO2复合氧化物的组成与性能

通过控制共沉淀时溶液中Ｃｄ／Ｓｎ摩尔比的方法，合成了物相组成不同的ＣｄＯ－ＳｎＯ２复合氧化物粉料，探讨了相组成与材料电导及气敏性能之间的关系。     

α-Fe2O3气敏材料制备及掺杂效应近期发展

本文综合介绍了α－Ｆｅ２Ｏ３气敏材料近年来在制备方法（含影响因素）、防团聚技术、掺杂效应（含气敏机理）上的研究新进展，提出了今后气敏传感器研究及改进方向。     

氧化锌薄膜/锡掺杂玻璃光波导元件及其对氯苯的气敏性研究

建立了玻璃光波导气敏元件检测氯苯气体的方法.采用浸渍-提拉法将ZnO敏感膜固定在锡掺杂玻璃光波导表面,研制出了检测氯苯气体的ZnO薄膜/锡掺杂玻璃光波导气敏元件,并用该玻璃光波导气敏元件对挥发性有机气体进行了检测.实验结果表明,在室温下,气敏元件对氯苯气体有明显的响应,而对相同浓度的其它挥发性有机气体的响应相对较小,对...     

7,7,8,8—四氰基对苯醌二甲烷的光伏—气敏特性

用表面光电压谱技术研究了7,7,8,8-四氰基对苯醌二甲烷多晶的光伏-气敏特性。结果表明,在较高真空度条件下,该化合物有两类不同的表面光电压响应峰,分别位于390 nm(P_1)和480 nm(P_2)。探针气体吸附证明,P_1表现出较强的受体性,而P_2则显示出给体性质。给体性分子与该化合物的∏键轨道作用,而受体分子与其C≡N端基作用。     

氧化锡多晶电导的氧空位控制模型

SnO_2、ZnO等金属氧化物的气敏特性通常以它们在不同气氛中电导值的变化来体现。为弄清这类多晶材料及气敏元件电导变化的基本规律,本文根据表面势垒控制模型和晶界势垒控制模型讨论了氧空位密度对SnO_2多晶材料及气敏元件电导值的重要影响,并根据SnO_2多晶电导的氧空位控制模型,讨论了在不同烧结条件下元件电导的变化规律,并用X光电子能谱(XPS)对结果进行了分析。     

配位-沉淀法制备镍酸镧敏感材料

用配位－沉淀法制备了片状镍酸镧粉体,通过Ｘ射线射,热重－着热分析及扫描电子显微镜等实验段材料的结构组成及性能进行一分析表征表。研究表明该法制备ＬａＮｉＯ３具有方法简单,易过滤,制备时间短等特点。     

Tetrakis-4-(2,4-di-tertamylphenoxy)phthalo-cyaninato-polysiloxane Langmuir-Blodgett Films and Their Gas Sensitive Properties

Tetrakis-4-(2,4-di-amylphenoxy) phthalocyaninato-polysiloxane (R₁PcPS) Langmuir-Blodgett (LB) films were prepared onto planar interdigital microelectrode arrays and their pas sensitive, properties were investigated. The results of response and recovery process were Shown when the (R₁PcPS) LB films were exposed to NH₃, NO₂ and I₂ gas in air. THh gas sensitive sensor consisting of (R₁PcPS) LB film can be used to detect NH₃ gas down to 0.0005% in air.     

Gas permeabilities of polyurethane films for fresh produce packaging: Response of O2 permeability to temperature and relative humidity

Thermoplastic shape memory polyurethane (SMPU) polymers were synthesized, cast to films, and their gas barrier properties were characterized. In addition, performance of an optical method was assessed by measuring oxygen permeability (P_O2) of the films. P_O2 of the SMPU film was at least two times higher than that of low density polyethylene (LDPE and increased at higher relative humidity. Permselectivity (P_CO2/P_O2) of the SMPU film was 15, which is approximately three times higher than for LDPE. The film absorbed circa 18% water vapor at 98% relative humidity. The optical method agreed very well (maximum 20% deviation) with a standard carrier gas method in P_O2 measurement. Overall our results show that SMPU is an attractive polymer for fresh produce packaging.     

聚苯胺基LB膜的制备及气敏特性的研究

以聚苯胺 (PAN)为原料 ,利用LB(Langmuir Blodgett)超薄分子膜技术 ,制备了不同层数的纯聚苯胺LB膜及聚苯胺与乙酸 (AA)混合 (PAN AA)LB膜 ,对其进行了紫外 可见光光谱分析研究 ,并对不同层数的聚苯胺基LB膜的二氧化氮 (NO2 )气敏特性进行了研究 ,发现PANLB膜较PAN AALB膜具有更好的敏感性、响应性和可逆性 ,3层和 15层PANLB膜对相对百分比为 2 0× 10 -6NO2 的响应时间分别为 10s和 30s,15层PANLB膜的恢复时间约为 4min     

手持数显式乙醇测试仪的研制

用半导体氧化物气敏传感器及微控制器８９Ｃ５１研制的手持式数显乙醇测试仪能对气体中的乙醇含量进行现场实时检测。该文从硬件、软件两方面介绍其优化电路和抗干扰技术。该仪器具有灵敏度高、选择性好、抗干扰能力强等特点,可用于交通安全检测、酒厂和食品工厂发酵监控。     

Synthesis and properties of pH and temperature sensitive P(NIPAAm-co-DMAEMA) hydrogels

In order to investigate the influence of the continuous alkylamide sequence having pH sensitive unit on the temperature sensitivity of poly(N-isopropylacrylamide) (PNIPAAm)-based hydrogel, a monomer, N-(2-(dimethylamino) ethyl)-methacrylamide (DMAEMA), having an ethylamide group as well as an aliphatic tertiary amino group, was designed and synthesized. Hydrogels based on NIPAAm and DMAEMA were prepared via free radical polymerization. The resulted P(NIPAAm-co-DMAEMA) hydrogels were characterized in terms of maximum swelling ratio, swelling kinetics, temperature response kinetics, and effect of pH. The data obtained show that the novel hydrogels have the strong desire to respond to external temperature and pH stimuli. Importantly, because the P(NIPAAm-co-DMAEMA) hydrogels have the continuous alkylamide sequence containing isopropylamide pendant groups from PNIPAAm and ethylamide pendant groups from PDMAEMA, the incorporation of DMAEMA moiety not only provides the pH sensitivity, but also maintains the thermal properties of P(NIPAAm-co-DMAEMA) hydrogels, even as the molar percentage of DMAEMA moiety reaches 14 mol%.     

水凝胶纳米粒及其在生物医药领域的应用

作为环境响应性和纳米控释给药系统，水凝胶纳米粒主要用于毒副作用大、生物半衰期短、易被生物酶降解的多肽类、蛋白质等生物大分子药物的给药，在生物医药领域具有越来越广阔的应用前景。本文主要综述了水凝胶纳米粒的分类、制备方法及其在生物医药领域的应用。     

CO2‐ and O2‐Sensitive Fluorophenyl End‐Capped Poly(ethylene glycol)

Pentafluorophenyl end‐capped poly(ethylene glycol) (PF‐PEG‐PF) aqueous solution shows a lower critical solution temperature (LCST), which is sensitive to the type of gases dissolved in the solution. LCST increases from 24.5 to 26 °C when dissolved carbon dioxide is replaced by oxygen. The transparent‐to‐turbid transition is reversibly observed when the dissolved carbon dioxide in the PF‐PEG‐PF aqueous solution is exchanged with oxygen, and vice versa, at 24.5 °C. ¹⁹F NMR and ¹H NMR spectra of the PF‐PEG‐PF in D₂O suggest that 1) dehydration of PEG is the main reason of developing LCST of the PF‐PEG‐PF aqueous solution, 2) minute differences in the intermolecular interactions, as demonstrated by changes in the chemical shift of the PF‐PEG‐PF peaks, induce such a difference in LCST. This paper provides a new insight in designing a stimuli‐responsive polymer in that fine tuning of a phase transition can be controlled by the type of dissolved gas.