YSB-Ag复合电极在氧传感器中的应用研究

通过在氧化物电极材料中引入适量导电性能优良的金属Ag,降低了氧化物电极的电阻,改善其氧敏响应特性;研究了YSB-Ag复合电极在氧化锆氧传感器中的应用。结果表明:这种复合电极具有较低的电阻值和很好的低温氧敏响应特性,在不使用加热装置条件下,氧传感器的起始工作温度可以降低至450℃左右,池内阻在100Ω以下。     

ZnO薄膜的成分与电阻率的关系

为了弄清ZnO薄膜的导电机理及电阻率与工艺参数的关系,对薄膜的成分进行了精确测定。结果表明,电阻率主要受膜中Zn/O比的影响。对电导机理提出的模型认为,主要由导带电子传导和缺陷间跳跃电导决定膜的电导性能。膜中施主为氧空位,陷阱由填隙氧原子提供。当膜中Zn多于氧时,主要为导带电导,而氧多于Zn时,则以跳跃电导为主。     

纳米点调控氧化物忆阻器电导特性研究进展

从调控氧化物忆阻器电导特性的主要方法与机理出发,综述了纳米点在氧化物忆阻器电导行为调制及其参数稳定性改善等方面的研究进展。针对纳米点调控氧空位的扩散迁移、电场迁移及其共同作用,分析了纳米点对氧化物忆阻器的电形成过程、开态过程和关态过程的作用机制,并讨论了其对参数均一性、耐久能力、疲劳特性、电阻比率及开关时间等参数的影响。结果表明,纳米点的引入可以显著改善忆阻器性能参数的稳定性和可控性,并进一步指出纳米点在优化其电导特性方面存在的不足和可能的解决措施,预测了性能优化的氧化物忆阻器在非易失存储、人工神经网络等领域的应用前景。     

Bi_2Cu_(0.1)V_(0.9)O_(5.35-δ)固态电解质化学溶液法的合成与性能

用化学溶液法合成了Bi2Cu0.1V0.9O5.35-δ(BICUVOX.10)材料,研究了材料的物相、表面形貌和电学特性.BICUVOX.10薄膜具有室温稳定的高电导γ相.在LaNiO3/Si衬底上,BICUVOX.10薄膜具有(001)择优取向,平均晶粒大小约为200nm.低频范围的介电损耗来源于氧空位的短程扩散,BICUVOX.10薄膜主要表现为晶粒电导特性.BICUVOX.10薄膜中氧离子电导激活能约为0.3 eV,氧离子电导率约为5×10-2S.cm-1.     

氧的电子探针定量分析

用电子探针显微分析的方法进行氧的直接定量，对于催化剂的研究和化工产品的分析鉴别等有一定的实际意义。但由于氧和其它超轻元素的特点，其定量至今仍是电子探针分析中的难题。氧化物体系的很多试样由于导电不良，需表面喷涂导电层（如碳等）。另外，试样在电子探针分析...     

RFe2O4体系电荷有序及相变研究

铁电材料广泛应用于包括记忆装置在内的现代电子设备中。传统的铁电性主要来源于离子位移，但研究人员在RF32O4结构的混合价氧化物中发现了一种基于有序电子的新机制，这种类型铁电材料的出现，使研制具有更高可控制性能的器件成为可能。     

用于纳电子器件的超薄氮氧硅薄膜的软失效电导

研究了2.5nm超薄氮氧硅薄膜的软击穿电导特性. 统计实验结果表明，软失效电导和软失效时间与环境温度之间均遵从Arrhenius规则，而且软失效电导和软失效时间遵从一个反对称的规律. 它们源于同一个应力诱生缺陷导电机制.     

纳米阴离子导体离子导电性能的研究进展

介绍了纳米技术在氧离子导体和氟离子导体的制备及导电性能研究方面的应用。纳米尺度的氧化物在烧结过程中致密化温度可降低50～200℃,最终产物的晶粒尺寸可小于1μm,离子电导率较高,可达到10–1S·cm–1量级。纳米氟离子导体与传统粗晶氟离子导体相比,具有明显的纳米尺寸效应,导电激活能可降低30%,离子电导率可提高1～2个数量级。     

（MgCoNi）O厚膜氧传感器的制备及特性研究

对厚膜（ＭｇＣｏＮｉ）Ｏ氧敏元件进行了制备，对元件的高温电导与氧分压关系进行了测试，微观结构分析及性能测试表明，当氧敏浆料中的玻璃相含量适当时，氧敏元件具有较大的机械强度及优异的氧敏工作特性。     

LaBaCo_2O_(5+δ)薄膜的电输运及氧敏性质研究

采用高分子辅助沉积法制备了Si基La BaCo2O5+δ(LBCO)薄膜,主要研究了Si基LBCO薄膜的电输运性质及氧敏性质。通过对LBCO薄膜的电输运性质研究,发现LaBaCo2O5+δ薄膜的激活能Ea为0.32 e V,远小于同类体材料PrBaCo2O5+δ激活能(Ea=0.67 e V),说明将材料薄膜化以后,有利于降低材料的激活能;此外,LBCO薄膜阻-温曲线满足小极化子热激化跳跃理论,证明该材料的导电机制是小极化子电子电导。氧敏性质研究发现,在较低的温度356℃下,当测试气体从氢气切换到氧气时,薄膜电阻从3×105Ω迅速下降到4.5×102Ω(ΔR≈3.0×105Ω),响应时间为4.2 s,说明在较低温度下,LBCO薄膜对氧气具有较高的敏感度。同时,发现LBCO薄膜材料导电能力并不与氧气的浓度成正比。     

A versatile high-permittivity phantom for EIT

Phantoms are frequently used in medical imaging systems to test hardware, reconstruction algorithms, and the interpretation of data. This report describes and characterizes the use of powdered graphite as a means of adding a significant reactive component or permittivity to useful phantom media for electrical impedance imaging. The phantom materials produced have usable complex admittivity at the electrical impedance tomography (EIT) frequencies from a few kilohertz to 1 MHz, as measured by our EIT system (ACT4) and by a commercial bioimpedance analyzer (BIS 4000, Xitron). We have also studied a commercial ultrasound coupling gel, which is highly electrically conductive and semisolid but that permits objects to move within it. The mixture of agar–graphite and gel–graphite, increases in permittivity and conductivity are proportional to the graphite concentration. We also report the use of a porous polymer membrane to simulate skin. A thin layer of this membrane increased resistance and the characteristic frequency of the phantoms, providing a promising candidate to simulate the effect of skin and the layered structure of a breast or other anatomical structure. The graphite also provides a realistic level of “speckle” in ultrasound images of the phantom, which may be useful in developing dual-mode imaging systems with ultrasound and the EIT.      

Acoustically actuated flextensional Si/sub x/N/sub y/ and single-crystal silicon 2-D micromachined ejector arrays

We propose using two-dimensional (2-D) micromachined droplet ejector arrays for environmentally benign deposition of photoresist and other spin-on materials, such as low-k and high-k dielectrics used in IC manufacturing. Direct deposition of these chemicals will reduce waste as well as production cost. The proposed device does not harm heat or pressure sensitive fluids and they are chemically compatible with the materials used in IC manufacturing. Each element of the 2-D ejector array consists of a flexurally vibrating circular membrane on one face of a cylindrical fluid reservoir. The membrane has an orifice at the center. A piezoelectric transducer generating ultrasonic waves, located at the open face of the reservoir, actuates the membranes. As a result of this actuation, droplets are fired through the membrane orifice. Ejector arrays were built with either Si/sub x/N/sub y/ or single-crystal silicon membranes using two different fabrication processes. We show that single-crystal silicon membranes are more uniform in their thickness and material quality than those of Si/sub x/N/sub y/ membranes. The single-crystal silicon membrane-based devices showed thickness and material uniformity across all the membranes of an array. This improvement eliminated nonuniform membrane resonance frequencies across an array as observed with Si/sub x/N/sub y/ membrane-based devices. Therefore, it should be possible to repeatably build devices and to predict their dynamic characteristics. Using the fabricated devices, we demonstrated water ejection at 470 kHz, 1.24 MHz, and 2.26 MHz. The corresponding droplet diameters were 6.5, 5, and 3.5 /spl mu/m, respectively.     

Bioinspired High Tolerant Vein–Membrane Al2O3 Coating

The vein–membrane structure inspired by insect wings is applied to the artificial structural design of materials, with the aim of enhancing the intrinsic low strain tolerance and bonding strength of Al₂O₃ coating. Al₂O₃ platelets with high aspect ratio are used as veins, forming a bioinspired vein–membrane structure along with the Al₂O₃ membrane. Further, Al₂O₃ platelets take “root” in the substrate, forming a bioinspired root–soil interlocking structure. The greatest highlight of this coating is that it can restrict the cracks to the submicron area enclosed by the vein. The multi-bioinspired structure enabled the Al₂O₃ coating to sustain strains as high as 8%, which is 2 orders of magnitude higher than the reported failure strain of Al₂O₃ film. The bonding strength is also increased by at least five times. The vein–membrane structure opens a novel technological space for the artificial structural design of materials.     

3.7～4.8 μm中红外带通滤光膜研制

以光学薄膜理论为出发点,系统介绍了3.7～4.8 m带通滤光膜的理论设计与优化、实际生产制备以及成品测试方法。考虑到膜料性能及膜层匹配等问题,分别选用锗和一氧化硅作为高低折射率材料,并以氧化铝作为薄膜基底。确定了滤光膜的基础膜系,并使用Filmaster软件对膜系进行了设计和优化计算。在薄膜蒸镀过程中,根据材料选取合适的镀制工艺。通过温度控制、离子辅助等方法研制出了可靠性与光谱特性皆优的带通滤光膜,并对其光谱特性及膜层质量等进行了测试。根据设计目标修改工艺参数,最终确定可行的工艺流程,从而研制出了符合光学性能设计指标的3.7～4.8 m带通滤光膜。     

Silica Films with Bimodal Pore Structure Prepared by Using Membranes as Templates and Amphiphiles as Porogens

Extended porous silica films with thicknesses in the range of 60 to 130 μm and pores on both the meso‐ and macroscale have been prepared by simultaneously using porous membrane templates and amphiphilic supramolecular aggregates as porogens. The macropore size is determined by the cellulose acetate or polyamide membrane structure and the mesopores by the chosen ethylene‐oxide‐based molecular self‐assembly (block copolymer or non‐ionic surfactants). Both the template and the porogen are removed during an annealing step leaving the amorphous silica material with a porous structure that results from sol–gel chemistry occurring in the aqueous domains of the amphiphilic liquid‐crystalline phases and casting of the initial template membrane. The surface area and total pore volume of the inorganic films vary from 473 to 856 m² g^–1, and 0.50 to 0.73 cm³ g^–1, respectively, depending on the choice of template and porogen. The combined benefits of both macro‐ and mesopores can potentially be obtained in one film. Such materials are envisaged to have applications in areas of large molecule (biomolecule) separation and catalysis. Enhanced gas and liquid flow rates through such membranes, due to the presence of the larger pores, also makes them attractive as supports for other catalytic materials.     

用于谐振式传感器的微型双层薄板热挠曲的研究

本文对微机械中热胀系数不同的材料构成的双层复合薄板在均匀温升下的挠曲特性进行了研究,提出了在均匀温升下双层薄板热挠曲求解的能量法,并给出了小挠度下中心挠度与板厚的解析关系,为薄膜谐振式传感器温度特性的研究和新型温度传感器的设计与开发打下了基础.     

多孔阳极氧化铝模板合成纳米点阵列的研究进展

多孔阳极氧化铝具有耐高温、成本低、空洞分布均匀有序且大小可控等优点,是制备高度有序纳米材料的理想模板.介绍了多孔阳极氧化铝模板的制备和以多孔阳极氧化铝为模板采用常规方法制备高度有序纳米点阵列材料的最新研究进展,以及纳米点阵列的应用前景.     

Engineering a Robust,Versatile Amphiphilic Membrane Surface Through Forced Surface Segregation for Ultralow Flux‐Decline

Unlike biofoulants/pollutants, oil foulants/pollutants are prone to coalesce, spread and migrate to form continuous fouling layer covering on the surfaces. Therefore, such kind of fouling can not be simply alleviated by hydrophilic modification with currently extensively used antifouling materials such as poly(ethylene glycol) (PEG)‐based or zwitterionic polymers etc. In the present study, an amphiphilic porous membrane surface, comprising hydrophilic fouling resistant domains and hydrophobic fouling release microdomains, is explored via a "forced surface segregation" approach. The resultant membranes exhibit both superior oil‐fouling and bio‐fouling resistant property: membrane fouling is exquisitely suppressed and the permeation flux‐decline is decreased to an ultralow level. It can be envisaged that the present study may open a novel avenue to the design and construction of robust, versatile antifouling surfaces.     

Visible‐Light‐Activated Photocatalytic Films toward Self‐Cleaning Membranes

Membranes are among the most promising means of delivering increased supplies of fit‐for‐purpose water, but membrane fouling remains a critical issue restricting their widespread application. Coupling photocatalysis with membrane separation has been proposed as a potentially effective approach to reduce membrane fouling. However, commonly used materials in photocatalysis limit use of low‐cost sources such as sunlight due to their large bandgaps. There are few examples of in situ photocatalytic self‐cleaning of membranes, with removal from the filtration system and ex situ illumination being more common. In this work, a visible‐light‐activated photocatalytic film prepared by nitrogen doping into the lattice of TiO₂ is deposited on commercial ceramic membranes via atomic layer deposition. The synergy between membrane separation and redox reactions between organic pollutants and reactive oxygen species produced by the visible‐light‐activated layer offers a possibility for stable and sustainable membrane operation under in situ solar irradiation.     

Superprotonic Conductivity of MOFs and Other Crystalline Platforms Beyond 10−1 S cm−1

The proton-exchange membrane (PEM) is a fundamental module of proton-exchange membrane fuel cells (PEMFCs), permitting proton passage and thus governing the overall performance of PEMFCs. Till now, Nafion has been the extensively used marketable PEM material due to its high protonic conductivity of 10⁻²–10⁻¹ S cm⁻¹ under high relative humidity and 80–85 °C. On the other hand, crystalline materials such as metal-organic frameworks (MOFs), coordination polymers (CPs), covalent organic frameworks (COFs), hydrogen-bonded organic framework (HOFs), metalo hydrogen-bonded organic framework (MHOFs), and polyoxometalates (POMs) are emerging as potential PEM materials, where crystallinity has paved the way to study the conduction pathway and associated mechanisms to understand structure-function relationships. However, to date, ultrahigh superprotonic conductivity to the level of 10⁻¹ S cm⁻¹, close to Nafion, is relatively scarce for the crystalline proton conductors. In this review, the discussion is focused on materials that demonstrate a conductivity order of 10⁻¹ S cm⁻¹ and higher for those individual crystalline platforms (to be on the equal footing and superior to nafion, respectively) based on their synthesis approach while highlighting the design norms and key features for attaining such ultrahigh conductivity. While a critical analysis is made, the key issues and future prospects are also addressed.