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oe1(光电查) - 科学论文

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出版时间
  • 2018
研究主题
  • electropolymerization
  • polyporphyrin films
  • quartz crystal microbalance method
  • oxygen electroreduction.
应用领域
  • Applied Chemistry
机构单位
  • G.A. Krestov Institute of Solution Chemistry of RAS
  • University Union Nicola Tesla
  • Ivanovo State University of Chemistry and Technology
61 条数据
?? 中文（中国） ▾

  • Powder Quartz/Nano-TiO2 Composite: Mechanochemical Preparation and Photocatalytic Degradation of Formaldehyde

    摘要： Powder quartz (PQ)/nano-TiO2 composite was prepared by a mechanochemical method. Based on as-prepared PQ/nano-TiO2 composite, we prepared interior paints and investigated the degradation efficiency of formaldehyde (DEF). Scanning electron microscopy showed that nano-TiO2 got well dispersed by the adding of PQ. Thermogravimetric analysis indicated that the mass ratio of 4:1 was a relatively good proportion for the most production of PQ/nano-TiO2 composite. Fourier transform-infrared spectrometry showed that the peak position of Ti-O-Si bond varied with the milling time. At the early stage, no characteristic peak of Ti-O-Si bond was observed, while at the later stage, new peaks at 902 cm-1 and 937 cm-1 appeared. Meanwhile, PQ/nano-TiO2 composite-based interior paint exhibited significant DEF of 96.3% compared to that consisting of sole nano-TiO2 of 92.0% under visible light illumination. As an abundant mineral resource, PQ would make interior paints with HCHO purifying effect much more efficient and cheaper.

    关键词： powder quartz,formaldehyde,interior paint,nano-TiO2

    更新于2025-11-21 11:18:25

  • A review of Quartz Crystal Microbalances for Space Applications

    摘要： The aim of this work is a technical review about Quartz Crystal Microbalance (QCM) sensors used in space missions, i.e. Space Shuttle flights, i.e. NASA Space Transportation System (NASA STS) and satellite missions, that aimed at monitoring the contamination generated by outgassing processes of materials onboard satellites and sensitive payloads. The contamination processes are critical for scientific instrumentation (e.g. optics, telescopes, detectors) because scientific measurements and performances can be jeopardized or worsened by uncontrolled contamination. This issue has been addressed by the space agencies, e.g. NASA, ESA and JAXA that have implemented many different studies to monitor the material outgassing and degradation in space environment. During the past years, the QCM sensors have become the baseline solution for measuring material outgassing and characterizing the on-orbit contamination environment. This work summarizes the main QCM applications in Space and their findings, providing an overview of the sensors’ performances in terms of stability, power, data rate, measurement accuracy and resolution. Different QCM technologies will be compared highlighting the advantages of their use for the next space missions and instrumentations that require an accurate monitoring of contamination environment. In particular, due to more severe contamination requirements for next payloads and instrumentations, QCM sensors would be useful to estimate the cleanliness degree by evaluating the induced contamination and degradation on sensitive instrumentations.

    关键词： quartz crystal microbalance,contamination monitoring,spacecraft contamination,molecular and particulate contamination,outgassing,satellite contamination

    更新于2025-09-23 15:23:52

  • Reduction and compensation of humidity measurement errors at cold temperatures using dual QCM humidity sensors based on graphene oxides

    摘要： One of the difficulties in measurements of relative humidity in a variety of environments is temperature-dependence especially at cold temperatures. Here, we report on the reduction and the compensation of temperature effects on humidity measurements using dual humidity sensors based on quartz crystal microbalance (QCM). Graphene oxide film is coated on quartz crystals as a humidity sensing layer for the detection of water sorption by the change of resonance frequency. Relative humidity in a test chamber, where dual QCM humidity sensors are located, is precisely controlled using a humidity generator at the temperature range from 20 °C to ?60 °C. It is found that single QCM humidity sensors measure humidity significantly higher than reference relative humidity by the generator as temperature is lowered due to the temperature-dependent resonance of quartz crystals. In an attempt to cancel out the temperature-dependent oscillation of QCM sensors, the ratio of resonance frequencies of dual QCM humidity sensors is used. Consequently, temperature-dependent errors in humidity measurement at low temperatures are evidently reduced. For the compensation of the remaining errors in the humidity measurement by dual QCM humidity sensors, a single formula is empirically obtained. After the compensation of low temperature effects, the dual QCM humidity sensors provide the measurement capability in terms of residual errors less than 1.1%rh throughout temperatures from 20 °C to ?60 °C. This study provides a useful insight to extend the applicability of QCM-based humidity sensors to environments with cold temperatures.

    关键词： Compensation,Graphene oxide,Cold temperature,Quartz crystal microbalance,Humidity measurement,Humidity sensor

    更新于2025-09-23 15:23:52

  • Haloalkanes and aromatic hydrocarbons sensing using Langmuir–Blodgett thin film of pillar[5]arene-biphenylcarboxylic acid

    摘要： Here, a pillar[5]arene derivative including biphenylcarboxylic acid groups was designed for obtaining a macrocycle with an ideal cavity for volatile organic compounds. The pillar[5]arene-biphenylcarboxylic acid (P5-BPCA) based Langmuir-Blodgett (LB) thin films were produced onto 50 nm thick gold-coated glass and 3.5 MHz quartz crystal substrates to form a thin film chemical sensor element. Surface plasmon resonance (SPR) and Quartz crystal microbalance (QCM) techniques were employed to characterize all the P5-BPCA LB thin film layers. The mass of LB film layer loaded onto a quartz crystal and the resonance frequency shifts per layer were determined to be 711.71 ng per layer (2.68 ng mm?2) and 48.24 Hz per layer, respectively. The P5-BPCA LB thin film sensor element was exposed to various haloalkane and aromatic hydrocarbon vapors. The sensitivities of the P5-BPCA LB film sensor were determined between 1.776 and 3.976 Hz ppm-1. Sensitivity with detection limits were obtained between 0.754 and 1.689 ppm against organic vapors. The results showed that P5-BPCA LB thin film was highly selective with a large response to chloromethane vapor.

    关键词： Quartz Crystal Microbalance,Pillararene,Langmuir-Blodgett,Volatile Organic Compounds,Swelling,Surface Plasmon Resonance

    更新于2025-09-23 15:23:52

  • Production of industry-specific quartz raw material using Sri Lankan vein quartz

    摘要： High-purity quartz is a major raw material in many high-tech applications. Sri Lanka is rich in quartz mineralization, with an abundance of major vein quartz deposits with purity levels exceeding 99.5% SiO2. Developing high-tech products requires considerable capital investment, expertise, and advanced processing technologies which are lacking in developing countries like Sri Lanka. In most developing countries raw quartz with limited added value is exported to industrialized countries in grit and powder forms only after size reduction of run-of quarry quartz. We here examine an alternative approach, in which value addition is achieved by production of semi-processed and processed industry-specific quartz raw material for export. Chemical compositions of major types of vein quartz from seven vein quartz deposits and products of mass scale quartz processing at a plant located in the Badulla district of Uva Province, Sri Lanka were determined in study. Critical step evaluation in mining, transport and processing activities was carried out with reference to Fe and other critical trace elements, from data determined using inductively coupled plasma optical emission spectroscopy and atomic absorption spectroscopy. The results show that industrially critical trace element contents vary with type of quartz, association of accessory minerals, physical separation methods, transport practices, and comminution methods. We conclude that industry-specific quartz raw material can be produced through a combination of selective mining and exercising quality control during mining, transportation and processing activities.

    关键词： Quartz,High-quality quartz,Quartz purification,Quartz raw material

    更新于2025-09-23 15:22:29

  • Quartz-containing glass-ceramics in the SiO <sub/>2</sub> -Li <sub/>2</sub> O-K <sub/>2</sub> O-MgO-CaO-Al <sub/>2</sub> O <sub/>3</sub> -P <sub/>2</sub> O <sub/>5</sub> system

    摘要： Volume crystallization of quartz, triggered by adding P2O5, was investigated in the multicomponent SiO2–Li2O–K2O–MgO–CaO–Al2O3–P2O5 glass system. Glass‐ceramics comprising quartz as the main crystal phase besides lithium disilicate (Li2Si2O5) as a minor crystal phase were produced by controlled crystallization from the parent glass. According to quantitative crystal phase analysis by means of Rietveld refinement the mass fraction of the minor Li2Si2O5 phase decreased with increasing P2O5 content, while the fraction of quartz increased. Scanning electron microscopy revealed lath‐like Li2Si2O5 embedded in a matrix of rather globular quartz crystals forming an interlocking microstructure. Well machinable glass‐ceramics with a mean biaxial flexural strength of about 300 MPa and a fracture toughness of about 2.0 MPa × m0.5 could be realized. With mean values ≥13.6 × 10?6 K?1 the glass‐ceramics coefficient of thermal expansion is close to the one reported for low‐quartz crystals. The ease of production based on conventional glass melting and fabrication technology together with the good mechanical, optical, and machining properties enables the application of these materials in prosthodontics.

    关键词： nucleation,lithium disilicate,low-quartz,glass-ceramics,quartz

    更新于2025-09-23 15:22:29

  • Quartz force-sensitive resonator cluster using energy trapping theory

    摘要： The quartz resonator can be used as a force-sensitive element for sensors. The resonance energy distribution of thickness-shear quartz crystal is derived and calculated using the energy trapping theory. To reduce temperature and other interference factors as well as improve force-sensitivity, a multi-electrode force-sensitive resonator cluster is designed based on resonance energy distribution results. The output frequency signals of the resonator cluster are subtracted from each other to form beat frequency signals to suppress the temperature and other interference factors using the common mode rejection principle. Next, the beat frequency signals are superimposed to improve the overall force-sensitivity of the quartz crystal resonator cluster. The experimental results show that the temperature characteristics of the quartz resonator cluster are better than the traditional single electrode resonator and that the frequency stability reaches 10?10 orders of magnitude. The overall force-frequency coef?cient of the resonator cluster increases to 9992 Hz/N.

    关键词： Quartz force-sensitive resonator cluster,thickness-shear quartz crystal,energy trapping

    更新于2025-09-23 15:22:29

  • Granular Inhomogeneity Formation during Quartz Glass Melting

    摘要： This paper examines the formation of fine-grain inhomogeneity in quartz glass. We demonstrate that this defect emerges during the melting of fine-particle crystalline raw materials and the formation of a three-dimensional intergranular network, which contains a high impurity concentration and has a disordered structure. The present results are inconsistent with the existing believe that incomplete melting of quartz grains is the main cause of the development of fine-grain inhomogeneity. In contrast, prolonged high-temperature heat treatment increases the intergranular impurity concentration and intensifies the effect.

    关键词： quartz grit grains,grain boundaries,structural impurities,structure of quartz glass

    更新于2025-09-23 15:22:29

  • Humidity sensing properties of metal organic framework-derived hollow ball-like TiO2 coated QCM sensor

    摘要： This paper demonstrates three kinds of TiO2 with hollow ball, nanosphere, and nanoflower nanostructures coated quartz crystal microbalance (QCM) humidity sensors, which were synthesized by metal organic framework (MOF)-derived, hydrothermal and solvothermal route, respectively. The compositional and morphological characteristics of three kinds of TiO2 nanostructures were characterized by means of X-ray diffraction (XRD), specific surface area analysis (BET), scanning electron microscopy (SEM) and water contact angle measurement. We found that the surface structure plays a crucial role in the humidity-sensing response properties of QCM sensors. The humidity sensing experiment was performed at room temperature. The MOF-derived hollow ball-like TiO2 coated QCM sensor exhibited excellent humidity sensing characteristics over a wide RH range (0%-97%RH), such as high sensitivity (33.8 Hz/%RH), good repeatability and short dynamic response/recovery times (5 s/2 s). In addition, Langmuir adsorption model was developed to explain the humidity-sensing properties of the TiO2-based QCM sensor. This work proves that MOF-derived hollow-ball TiO2 is a potential candidate nanomaterial for humidity sensor fabrication.

    关键词： humidity sensor,Langmuir adsorption model,quartz crystal microbalance,hollow ball-like TiO2

    更新于2025-09-23 15:22:29

  • Fabrication and electromagnetic wave absorption property of quartz ceramics with a gradient distribution of BaTiO3

    摘要： Quartz ceramics with a uniform/gradient distribution of BaTiO3 (U/G–SO–BTO) are fabricated by cold pressing a powder blend with BTO followed by sintering and using a combined technique of spreading the powder blends with gradually increased BTO layer–by–layer and sintering. The electromagnetic wave absorption properties of these two ceramics are studied in detail. For U–SO–BTO samples, the primary electromagnetic re?ection is strong due to the aggravated impedance mismatch at their surfaces. The electromagnetic wave re?ectivity of U–SO–BTO could only reach ?7.0 dB when the sample thickness is 6 mm and the BTO content is 8.0 wt%, and it decreases slightly to ?8.1 dB when the sample thickness is increased to 10.0 mm and the BTO content is decreased to 5.0 wt% simultaneously. For G–SO–BTO samples, electromagnetic waves could enter with little re?ection due to the weak surface impedance mismatch, and the electromagnetic waves entering these samples could propagate forward while being absorbed gradually with little re?ection because of the weak impedance mismatch at the interfaces. The G–SO–BTO samples are promising excellent electromagnetic absorbing materials because their electromagnetic wave re?ectivity could reach a level lower than ?12.0 dB and could decrease further from –12.2 to ?13.1 dB as the layer thickness increases from 1.0 to 2.0 mm.

    关键词： Impedance mismatch,Electromagnetic wave absorption,Quartz ceramics,Electromagnetic re?ection,Gradient distribution,BaTiO3

    更新于2025-09-23 15:22:29