共查询到20条相似文献,搜索用时 78 毫秒
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本文以聚苯乙烯磺酸钠为湿敏材料制备了高分子电阻型湿度传感器,研究了其在高温高湿环境下,施加交流电激励后的老化行为。考察了通电电压、通电时间等对传感器响应特性的影响,并对其老化机理进行了探讨。提出通电老化后,湿敏材料在不同湿度下的电阻变化决定于高温高湿环境造成的溶解效应和施加电压后引起的通道效应和离子破坏效应。研究表明,在较高湿度环境下(87~93%RH),施加800mv的电压可加速湿敏材料的老化过程,使湿度传感器响应信号较快达到稳定,从而有望改善湿度传感器的稳定性。 相似文献
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SnO2-K2O-LiZnVO4系材料湿敏性能及导电机理的研究 总被引:1,自引:0,他引:1
采用共沉淀法制备出SnO2-K2O-LiZnVO4系湿敏粉体,考察了液相掺杂K 对材料湿敏特性的影响,并用直流特性法对材料的导电机理进行了分析.实验结果表明,适当的K 液相掺杂可使材料具有低湿电阻小,灵敏度适中的特性.直流特性法分析表明,材料属电子-离子混合导电机制,且离子电导成分越多材料的湿敏特性越好. 相似文献
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碱金属掺杂的铁系陶瓷湿敏材料特性研究 总被引:3,自引:0,他引:3
本文报导了碱金属掺杂对以 Fe_2O_3为基的陶瓷材料湿敏特性影响的研究结果。碱金属掺杂对改善材料敏感性与微组织结构有显著作用。研究发现,K~+,La~(3+)等离子的掺杂能明显降低材料固有阻值,提高低湿区敏感特性,改善阻—湿特性的线性关系。文中对水法处理与多元掺杂对减小材料湿滞,提高感湿灵敏度的作用机制给予了讨论。 相似文献
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WANG Jinxing LIU Tianmo LI Jiang 《材料导报》2004,18(Z3):116-118
综述了近年来国内外发展迅速的高分子电容式湿敏材料的研究状况,并对其今后的研究方向作了分析与展望. 相似文献
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E. Kulatov Y. Uspenskii H. Mariette J. Cibert D. Ferrand H. Nakayama H. Ohta 《Journal of Superconductivity》2003,16(1):123-126
Electronic structure and magnetic properties of Ga1–x
Mn
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As, Ga1–x
Mn
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N, Zn1–x
M
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O, and Zn1–x
M
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Te (M=V, Cr, Mn, Fe, and Co) diluted magnetic semiconductors (DMS) are calculated by the tight-binding LMTO method in the 64-atom supercell. Calculations are made at several x with varied spatial distribution of dopant atoms and codoping of DMSs. The results show that stability of the ferro- and antiferromagnetic (FM and AFM) states in DMSs strongly correlates with the occupation and energy position of 3d-dopant bands. Adequacy of the double exchange and superexchange mechanisms for explanation of the FM vs. AFM competition is discussed. 相似文献
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S. Lee D. Y. Shin L. V. Titova M. Kutrowski J. K. Furdyna M. Dobrowolska 《Journal of Superconductivity》2003,16(2):453-456
Magneto-optical experiments were carried out on structures comprised of multiple layers of self-assembled quantum dots (QDs) involving diluted magnetic semiconductors (DMSs). Photoluminescence (PL) from interband ground state transitions was clearly observed in these DMS-based QD systems. The PL energy from QD multilayers appears at a lower energy than that emitted by a single QD layer, suggesting that there exists electronic coupling between the QD layers. When an external magnetic field is applied, the PL peaks from QDs both in single-layer and in multilayer form exhibit large Zeeman shifts and a significant enhancement of intensity, a behavior that is typical for many low dimensional systems involving DMSs. In contrast to this behavior, however, we have observed a decrease of the PL intensity as a function of magnetic field in multilayer structures where alternating QW layers contain DMS and non-DMS QDs. We will show evidence that this effect arises from carrier transfer between pairs of QDs from adjacent layers (double QDs) due to the large Zeeman shifts of the conduction and valence bands characteristic of DMS QDs. 相似文献
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本文采用从头计算的方法研究了基于过渡性金属共掺杂Ⅱ-Ⅵ族稀释半导体的磁性和电子结构.并系统的研究了氧化锌基的稀释半导体铁磁态的稳定性和对其材料设计.在所有的共掺杂体系中,发现(Mn,Co),(Co,Ni)和(Mn,Ni)共掺杂体系是铁磁态的,而(Fe,Ni)共掺杂体系是自旋玻璃态.另一方面,Fe-,Co-和Ni掺杂ZnO基系统的稳态是铁磁态.同时,本文研究了ZnO基稀释半导体的载流子传导铁磁性,计算分析了电子态密度,铁磁态的稳定性.结合双交换和超交换理论解释共掺杂稀释半导体的磁性机理. 相似文献
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J. Kudrnovský I. Turek V. Drchal F. Máca J. Maek P. Weinberger P. Bruno 《Journal of Superconductivity》2003,16(1):119-122
The Curie temperature of diluted (Ga,Mn)As magnetic semiconductors in the presence of As antisites is studied from first principles. We map total energies associated with rotations of Mn-magnetic moments onto the effective classical Heisenberg Hamiltonian which is treated in the mean-field approximation to find the Curie temperature. The presence of donors strongly reduces the Curie temperature and gives rise to a ground state with a partial disorder of local moments. We show that the observed dependence of the Curie temperature on the Mn concentration indicates that the concentration of As antisites increases with the Mn content. 相似文献
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采用静电纺丝法制备了多级中空结构的SnO2纳米纤维, 然后将SnO2纳米纤维置于90℃乙酸锌溶液中, 恒温水浴条件下, 在SnO2纳米纤维上生长了ZnO纳米球, 形成了异质结构的SnO2/ZnO复合纳米纤维。分别通过XRD、SEM、EDX和XPS等表征手段对异质复合纳米纤维SnO2/ZnO材料的结构、形貌及元素含量进行了表征分析。异质结构的SnO2/ZnO复合纳米纤维保持了SnO2纳米纤维多级中空的纤维结构, SnO2纳米纤维长度约为300 nm, 依附于SnO2纤维表面的SnO2纳米颗粒生长的ZnO纳米球直径为250~300 nm。采用静态气体测试系统对异质复合纳米纤维SnO2/ZnO气敏元件的气敏性能进行了测试。测试结果表明: 异质复合纳米纤维SnO2/ZnO气敏元件在最佳工作温度350℃下, 对(0.5~100)×10-6丙酮具有优异的响应灵敏度、较好的选择性和长期稳定性。异质复合纳米纤维SnO2/ZnO中存在于ZnO纳米球与SnO2纳米颗粒间的N-N同型异质结导致复合材料晶界势垒高度的降低, 改善了电子与空穴的输运特性, 促使SnO2/ZnO异质复合纳米纤维的吸附能力大大增强, 从而改善了SnO2/ZnO元件的丙酮敏感特性。 相似文献
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Wearable electronics are attracting increasing interest due to the emerging Internet of Things (IoT). Compared to their inorganic counterparts, stretchable organic semiconductors (SOSs) are promising candidates for wearable electronics due to their excellent properties, including light weight, stretchability, dissolubility, compatibility with flexible substrates, easy tuning of electrical properties, low cost, and low temperature solution processability for large-area printing. Considerable efforts have been dedicated to the fabrication of SOS-based wearable electronics and their potential applications in various areas, including chemical sensors, organic light emitting diodes (OLEDs), organic photodiodes (OPDs), and organic photovoltaics (OPVs), have been demonstrated. In this review, some recent advances of SOS-based wearable electronics based on the classification by device functionality and potential applications are presented. In addition, a conclusion and potential challenges for further development of SOS-based wearable electronics are also discussed. 相似文献