Large Dynamic Response Research Articles

Effects of catalytic combustion behavior and adsorption/desorption properties on ethanol-sensing characteristics of adsorption/combustion-type gas sensors

ABSTRACT Adsorption/combustion-type gas sensors, subspecies of catalytic combustion-type gas sensors, show large dynamic responses to volatile organic compounds (VOCs) under the operation with a mode of pulsed temperature heating, because of the flash catalytic combustion of target VOCs adsorbed on the gas-sensing films. Catalytic combustion behavior of ethanol over γ-Al2O3 powders loaded with and without 1 wt% Pt and/or 10 wt% metal oxide (MO: CeO2 or Bi2O3) and their adsorption/desorption properties of ethanol (adsorption temperature: 150°C) were investigated, and then the ethanol-sensing characteristics of the sensors utilizing the gas-sensing materials (low and high temperatures under dynamic operation: 150°C and 450°C, respectively) have been discussed on the basis of the findings on both their catalytic combustion behavior and adsorption/desorption properties. Especially, the co-loading of Pt with CeO2 onto γ-Al2O3 was the most effective in enhancing the dynamic response, because the relatively small amounts of various compounds that were adsorbed on the surface at 150°C efficiently oxidized at the initial stage of the pulse-driven heating to form CO2. The effects of low and high temperatures under the pulse-heating operation on the ethanol-sensing properties of the sensor utilizing γ-Al2O3 co-loaded with Pt and CeO2 were also clarified on the basis of the above findings.

Mixing during Trapping Enabled a Continuous-Flow Microfluidic Smartphone Immunoassay Using Acoustic Streaming.

Smartphone-enabled microfluidic chemiluminescence immunoassay is a promising portable system for point-of-care (POC) biosensing applications. However, due to the rather faint emitted light in such a limited sample volume, it is still difficult to reach the clinically accepted range when the smartphone serves as a standalone detector. Besides, the multiple separation and washing steps during sample preparation hinder the immunoassay's applications for POC usage. Herein, we proposed a novel acoustic streaming tweezers-enabled microfluidic immunoassay, where the probe particles' purification, reaction, and sensing were simply achieved on the same chip at continuous-flow conditions. The dedicatedly designed high-speed microscale vortexes not only enable dynamic trapping and washing of the probe particles on-demand but also enhance the capture efficiency of the heterogeneous particle-based immunoassay through active mixing during trapping. The enriched probe particles and enhanced biomarker capture capability increase the local chemiluminescent light intensity and enable direct capture of the immunobinding signal by a regular smartphone camera. The system was tested for prostate-specific antigen (PSA) sensing both in buffer and serum, where a limit of detection of 0.2 ng/mL and a large dynamic response range from 0.3 to 10 ng/mL using only 10 μL of sample were achieved in a total assay time of less than 15 min. With the advantages of on-chip integration of sample preparation and detection and high sensing performance, the developed POC platform could be applied for many on-site diagnosis applications.

Near-infrared band Gold nanoparticles-Au film “hot spot” model based label-free ultratrace lead (II) ions detection via fiber SPR DNAzyme biosensor

Heavy metal lead ion (Pb2+) detection takes more and more attention due to its synergistic toxicity to human health and undegradability in environment. Currently, there are urgent demands for portable, anti-interference and economical Pb2+ sensors with high sensitivity and selectivity for environmental monitoring as well as modern healthcare in clinic. In this article, via compact and high performed titled fiber Bragg grating (TFBG) surface plasmon resonance (SPR) sensing platform, we present a novel DNAzyme biosensor for ultratrace Pb2+ detection on the basis of “hot spot” effect in near-infrared band. A gold nanoparticle (GNP)-on-Au film construction was built by DNAzyme and its substrate strand. When Pb2+ with high catalytic activity cleave the DNAzyme linked rA (ribonucleotide adenosine) containing substrate strand, making DNA double helix structure transform to a single strand, the GNPs that connected with DNAzyme fall down to the sensor surface. By FDTD simulation, we have demonstrated that the appearing “hot spot” effect due to the narrow gap (<2 nm) will eventually result in enhancement of the spectrum signal response which is directly related to the Pb2+ concentration. In experiments, the proposed fiber biosensor exhibits a competitive low limit of detection ∼ 8.56 pM, excellent selectivity against other environmentally related metal ions and the large dynamic response range from 10−11 M to 10−6 M. More significantly, clinical human serum samples were used to verify the practicability of this TFBG-SPR-DNAzyme-GNPs biosensor showing great potential value in various clinical applications as a high efficiency, portable and easy to miniaturization point-of-care testing technology.

Non-linear transient response of porous functionally graded truncated conical panels using GDQ method

Present study deals with large displacement transient dynamic response of truncated conical panels made of Porous Functionally Graded Materials (P-FGMs) using Generalized Differential Quadrature (GDQ) method. In this study, geometric non-linearity is taken into consideration through Green-Lagrange non-linear strain-displacement relations. First order shear deformation theory (FSDT) is utilized to take transverse shear effects into account. Virtual work principle is used to derive the equation of motion. The solution methodology utilizes GDQ method for spatial discretization of the variables. Newmark average acceleration method is implemented in time integration. Effects of different types of porosity distribution, porosity ratio and conical parameters on non-linear transient behavior of truncated conical panels are investigated for functionally graded material made of Zirconia/Aluminum (ZrO2/Al) considering various volume fraction coefficients.

Low-Cost and Fast-Response Resistive Humidity Sensor Comprising Biopolymer-Derived Carbon Thin Film and Carbon Microelectrodes

In this study, we present a highly responsive room-temperature resistive humidity sensor based on a shellac-derived carbon (SDC) active film deposited on sub-micrometer-sized carbon interdigitated electrodes (cIDEs). This monolithic carbon-based sensor demonstrates an excellent linear relationship with humidity and ohmic contact between the active carbon film and carbon electrodes, which results in low noise and low power consumption (∼1 mW). The active SDC film is synthesized by a single-step thermal process, wherein the temperature is found to control the amount of oxygen functional moieties of the SDC film, thereby providing an efficient means to optimize the sensor response time, recovery time, and sensitivity. This SDC–cIDEs-based humidity sensor exhibits an excellent dynamic range (0%–90% RH), a large dynamic response (50%), and high sensitivity (0.54/% RH). In addition, the two-dimensional feature (thickness ∼10 nm) of the SDC film enables a swift absorption/desorption equilibrium, leading to fast response (∼0.14 s) and recovery (∼1.7 s) under a humidity range of 0%–70% RH. Furthermore, the thin SDC-based sensor exhibited excellent selectivity to humidity from various gases, which in combination with its fast response/recovery promises its application for an instant calibration tool for gas sensors.

Dynamic of a planing hull in regular waves: Comparison of experimental, numerical and mathematical methods

The unsteady planing motion in waves is a complicated problem, that can lead to uncomfortable riding situation and structural damages due to large wave-induced dynamic responses and vertical accelerations. In the current research, this problem is investigated using different approaches, including towing tank tests, Computational Fluid Dynamics (CFD), and the 2D + t model. Results obtained from all three approaches are compared against each other in details. The spectral analysis shows that all motions can be nonlinear, but CFD and 2D + t model may predict weaker nonlinear behaviour at higher speed, especially for the case of vertical accelerations corresponding to longer waves. Interestingly, the vertical acceleration found by 2D + t model is seen to be under-predicted at moderate and long wavelengths and to be over-predicted at short waves. The values of sectional forces found by 2D + t model were compared against CFD results, showing that, while the 2D + t model computes smaller sectional forces, it can also compute negative sectional forces near the bow of the vessel at short waves when the boat exits the water. The emergence of negative sectional forces is likely to be the reason why the 2D + t model over-predicts the vertical acceleration in short waves.

A New Strategy for Large Dynamic Piezoelectric Responses in Lead‐Free Ferroelectrics: The Relaxor/Morphotropic Phase Boundary Crossover

AbstractOne of the key problems in the existing lead‐free piezoelectrics lies in how to further boost their dynamic piezoelectric responses, i.e., electrostrain and dynamic piezoelectric constants, in an effective and facile manner, making them comparable to those of widely used lead‐based counterparts. In this work, a new strategy is developed to largely improve the dynamic piezoelectric properties of lead‐free ferroelectrics using phase field simulations by combining the relaxor/ferroelectric crossover rendering potentially reversible electrostrain and the morphotropic phase boundary (MPB) providing easy paths of ferroelectric polarization rotations. Following the guidance of simulation results, Mn‐doped (Bi0.5Na0.5)TiO3–BaTiO3 lead‐free piezoelectric ceramics with relaxor/MPB crossover are synthesized. A large reversible electrostrain (Smax) of 0.55% with a promising piezoelectric constant d33* (Smax/Emax) of 917 pm V–1 at the designed relaxor/MPB crossover is obtained, outperforming almost all practical lead‐free counterparts when taking both electrostrain and dynamic piezoelectric constants into consideration. The strategy of utilizing relaxor/MPB crossover provides a new route for enhancing the dynamic piezoelectric responses in lead‐free ferroelectric perovskites.

Large amplitude vibrations of a deepwater riser conveying oscillatory internal fluid flow

A marine riser operated in deepwater could encounter harsh environmental conditions and exhibit complex vibration phenomena which require thorough investigation, especially using nonlinear geometric diagnosis. The aim of this paper was to propose a theoretical formulation for undertaking large amplitude vibration analysis of a deepwater marine riser conveying oscillatory internal fluid flow. The work-energy principle based on virtual displacement was utilized to formulate the riser mathematical model, accounting for internal strain energy and external work done. The geometric nonlinearity of the riser regarding extensible elastica theory was considered, which accounted for axial stretching and the large deformed curvature of the riser. The finite element method was utilized to form the equation of the motion system for solving numerical solutions. Based on Taylor's series expansion, the stiffness matrices with second-order nonlinear dynamic displacements of the riser were regarded in the equation of motion. The hydrodynamic ocean force modeled in terms of the squared riser velocity also yielded the nonlinear hydrodynamic damping matrix. The inertial force initiated by the pulsatile flow of transported fluid was taken into account as a harmonic oscillation representing the pump operation. Performing the Newmark time integration incorporated direct iteration on the equation of motion provided the nonlinear vibration response. A thorough parametric study was accomplished which investigated the influences of geometric nonlinearity, the forcing frequencies of a hydrodynamic wave, and an internal pulsatile flow on the large amplitude dynamic response characteristics of a deepwater riser.

Large shaking table tests of pile-supported structures in different ground conditions

This study investigates the dynamic response of structures and the effect of soil-structure interaction for flexible structures supported by pile foundations located in non-liquefiable and liquefiable sites as well as a rigid foundation. A series of large-scale shaking table experiments were performed, and accelerations and dynamic displacements of model superstructures were recorded during the shaking events. It was observed that the structure in non-liquefiable soil deposits had the highest accelerations due to the amplification of ground motion within the soil. On the other hand, the accelerations of the structure in liquefied site was small due to the increased dissipation of seismic energy. The structures founded on soil experienced residual (permanent) lateral displacements, with the permanent lateral displacement and tilting of the structure in the liquefied site being much larger. The structure on rigid foundation (i.e. foundation on rock or fixed base) experienced high accelerations and oscillatory displacement as the seismic energy could not be dissipated. Therefore, structures in liquefiable soil are prone to overturning damage due to failure of their foundations. Furthermore, the base shear force of the structure in the non-liquefied site was significantly larger than that in the liquefied site and fixed-base, indicating it would be more susceptible to shear failure. On the other hand, the fixed-base structure experienced relatively large acceleration and dynamic displacement responses, which indicates increased seismic demands on its structural members.

Finite Element Analysis of Displacement and Vibration Characteristics of Cantilevered Plate

The cantilever structure will produce a large dynamic response under the vertical load, which will cause the user’s discomfort. Therefore, the vibration characteristics of the structure caused by the vertical load are an important part of the comfort design of the cantilever structure in the normal use limit state. This article takes the vertical displacement of a cantilevered balcony slab on one side of a project under load as an example, and builds a model in the nonlinear finite element software to calculate the structural displacement and the factors of the cantilever length and the tensile reinforcement, and the corresponding comfort evaluation is carried out, which provides a reference for the vibration comfort evaluation of the house cantilever structure.

Combined “mesh flow” and “re-meshing” technique for coupled magnetic-mechanical problem on electromagnetic forming process

Electromagnetic forming process (EMF), which uses Lorentz forces to deform sheet metal, is one of the high-speed forming techniques. In this process, Maxwell’s and Newton’s equations are coupled to govern the electromagnetic and mechanical behavior. Coupled variational principles to simultaneously account for eddy current and large strain rate effects are formulated in this work. First, the electromagnetic loading on conductors is solved at constant intervals. Then, mechanical code is employed to solve the large deformation dynamic response considering high strain rates of sheet metal under the results from electromagnetic field. The two fields are solved independently using a staggered solution scheme. The deformation of sheet metal has been considered in pursuing the coupling between the electromagnetic and mechanical filed by using a combined “mesh flow” and “re-meshing” technique. To improve the accuracy of the numerical methods, a gradient smoothing technique based on edges of the background meshes is employed in this work. As an illustration, several such processes in practical problems are simulated. Numerical results showed great agreement with experimental ones.

Versatile decentralised control of the DC microgrid

This study proposes a versatile decentralised control strategy for the direct current (DC) microgrid based on the DC bus signalling method. Performance of the proposed control strategy is investigated under various generation and load disturbances in both grid-connected and islanded operation modes of the DC microgrid. The studies are conducted using a realistic DC microgrid study system simulated in the PSCAD/EMTDC software. The study results indicate that the proposed control strategy: (i) effectively maintains the power balance in the DC microgrid, (ii) effectively limits the DC bus voltage deviations under large disturbances, (iii) improves stability and dynamic response, (iv) does not curtail renewable power generation unless it is necessary, (v) does not require excessively large grid-tied converter and battery energy storage systems, and (vi) enhances system reliability, flexibility, modularity, and expandability.

Polymeric Micelles Encapsulating a Small Molecule SO2 Fluorescent Probe Exhibiting Novel Analytical Performance and Enhanced Cellular Imaging Ability.

Because of the limited knowledge on the relationship between molecular structure and analytical performance, developing a small molecule fluorescent probe with desirable response properties is usually a laborious work. On the other hand, the application of small molecule fluorescent probe in biological samples is always limited due to the unwanted interaction between dyes and biomacromolecules. Polymer micelles, thanks to its unique core-shell structure, may have the potential to improve these situations. However, utilization of polymer micelles to improve these situations is rarely explored. Herein, we engineered the first micellar SO2 nanoprobe Nano-Cz by self-assembly of a carbazole-based SO2 small molecule probe and an amphiphilic copolymer (DSPE-mPEG2000). The optical and cell imaging experiments revealed that Nano-Cz can work in 100% aqueous environment and act as an effective mitochondrial-targeting ratio SO2 nanoprobe. Compared with the single small molecule probe, Nano-Cz showed extraordinary large dynamic response range (0-0.7 mM vs 0-50 μM), eliminated signal interference from DNA and superior cellular imaging performance. These results clearly show the ability of polymer micelles in modulating sensors' analytical performance and reducing the signal interference from the unwanted interaction between small molecule probe and biomacromolecule, indicating that polymer micelles encapsulating single small molecule probe can provide us an alternative strategy to explore sensors with various performance and promote the biological application of fluorescent sensors. In addition, we hope that more and more polymer micelles would be used to construct biosensors in the future.

Effect of Clamping Torque on Large Deflection Static and Dynamic Response of a Cantilever Beam: An Experimental Study

The present paper reports an experimental study on the effect of finite clamping on static and dynamic characteristics of cantilever beam. The experiment is carried out with two different beams, each of which is clamped at two different locations resulting in two different geometry settings. Under each of these four settings, specimen is clamped under two different torque ratings giving rise to different finite clamping effect. Under the eight settings, coordinates of tip point under static loading are measured directly using scales and plumb at each load step; whereas, complete deflection profiles of loaded beam under each static load step are obtained through post-processing of images captured during experimentation. Such image processing is carried out manually using AutoCAD® and in-built AutoLISP® software. Strain measurements at each static load step are carried out by using strain gauge, a universal data acquisition system and the associated Catman Easy® software. To obtain loaded free vibration characteristics, loaded beam under each setting is disturbed by a rubber hammer and its dynamic response is recorded from strain gauge signal through Catman Easy® software. These dynamic strain readings of loaded beam are post-processed and FFT plots are generated in MATLAB® software and first two loaded natural frequencies of beam under each setting are obtained. Finally, effects of clamping torques on the static strain and deflection results and loaded natural frequencies for beam settings with the four different thickness to length ratios are reported in a suitable manner. The result reported may be useful as ready reference to develop a theoretical model of clamped beam like structures incorporating the effect of finite clamping.

Effect of Clamping Torque on Large Deflection Static and Dynamic Response of a Cantilever Beam: An Experimental Study

The present paper reports an experimental study on the effect of finite clamping on static and dynamic characteristics of cantilever beam. The experiment is carried out with two different beams, each of which is clamped at two different locations resulting in two different geometry settings. Under each of these four settings, specimen is clamped under two different torque ratings giving rise to different finite clamping effect. Under the eight settings, coordinates of tip point under static loading are measured directly using scales and plumb at each load step; whereas, complete deflection profiles of loaded beam under each static load step are obtained through post-processing of images captured during experimentation. Such image processing is carried out manually using AutoCAD®and in-built AutoLISP®software. Strain measurements at each static load step are carried out by using strain gauge, a universal data acquisition system and the associated Catman Easy®software. To obtain loaded free vibration characteristics, loaded beam under each setting is disturbed by a rubber hammer and its dynamic response is recorded from strain gauge signal through Catman Easy®software. These dynamic strain readings of loaded beam are post-processed and FFT plots are generated in MATLAB®software and first two loaded natural frequencies of beam under each setting are obtained. Finally, effects of clamping torques on the static strain and deflection results and loaded natural frequencies for beam settings with the four different thickness to length ratios are reported in a suitable manner. The result reported may be useful as ready reference to develop a theoretical model of clamped beam like structures incorporating the effect of finite clamping.

Erosion and heating of polyurea under cavitating jets

Earlier observation of cavitation erosion of polyurea coatings has shown that failure is due to synergetic effects between the locally imparted impulsive loads and heating of the material. Both result from the interaction between large amplitude cavitation bubble dynamic and material response and deformation. In order to investigate this interaction and quantify damage and heat generation in the material subjected to cavitation, cavitating jet tests were conducted on polyurea coated samples while measuring both the erosion of the polyurea and the temperature evolution. The effects of polyurea composition, cavitation field intensity, material of the substrate, and thickness of the polyurea coating on the erosion and temperature were deduced from the tests.

Sensitivity enhanced, stability improved ethanol gas sensor based on multi-wall carbon nanotubes functionalized with Pt-Pd nanoparticles

This paper reports a kind of ethanol gas sensor with enhanced sensitivity and improved stability. It utilizes multi-wall carbon nanotubes (MWCNTs) functionalized with Pt-Pd nanoparticles as catalyst. The MWCNTs with large specific surface area were used as carbon supports for the bimetallic catalyst (Pt-Pd) to enhance the electrochemical activity. The results demonstrate that the highest sensitivity (0.938 mV/ppm, which is ∼1.47 times higher than existing sensors) is realized by utilizing the catalyst with 80 wt% Pt-Pd. On the other hand, the highest value (2.877 mV/mg·ppm, ∼1.64 times higher than the reported ones) of the mass-normalized sensitivity is obtained with the 20 wt% Pt-Pd catalyst. Repeated detection of ethanol gas demonstrated a low limit of detection (LOD) of 3 ppm and a large dynamic response range from 3 to 400 ppm. The linear correlation coefficient (R2) of the signal was ≥0.998 from 0 to 400 ppm, and the performance degradation over 7 days was <2.7%, while that for existing sensors was 15%. These data illustrated that this sensor has potential applications for ethanol gas detection with high sensitivity.

Large deformation static and dynamic response of carbon nanotubes by mixed atomistic and continuum models

Multiscale modelling based finite element method is employed to investigate the nonlinear static and dynamic response of single walled carbon nanotubes and graphene sheets. The study is carried out using a four noded Kirchhoff rectangular field consistent finite element formulated in cylindrical coordinate system considering geometric and material nonlinearities. The atomic interactions are modelled through the Tersoff–Brenner potential. To avoid membrane locking, the circumferential strain is interpolated consistently using smoothed interpolation functions derived through the least square minimization. The accuracy and efficiency of the present approach are investigated by comparing the multiscale modelling based results with those obtained through molecular mechanics simulation. The quantitative contributions of material nonlinearity and different types of geometric nonlinearities (Green–Lagrange and von–Karman type nonlinearity) on the nonlinear response of carbon nanotubes and graphene sheets subjected to different kinds of load are brought out.

Vibration Control of Tower Structure with Multiple Cardan Gyroscopes

Tower structure is sensitive to hurricane and earthquake, and it is easy to generate large deflection and dynamic response. The multiple cardan gyroscope has two rotational degrees of freedom, which can generate strong moments to constrain the two horizontal orthogonal deflections if the rotor operates in high speeds, so the structural dynamic responses can be decreased. Hence, the method of dynamic control of the tower structure under wind load and earthquake action is proposed by using the multiple cardan gyroscopes as the dampers. The dynamic mechanism and the fixed axis principle of the multiple cardan gyroscope are introduced, and the dynamic equation of the gyroscope is established. The damping mechanism of the gyroscope is also described. For the tower structure equipped with the multiple cardan gyroscope dampers, the multidimensional control equation considering torsion effect is established, and the equivalent state space equation is presented. Taking a TV Tower with a number of gyroscope dampers as an analysis example, the structural dynamic responses and damping performance under fluctuating wind loads and earthquake action is studied. The results show that the multiple cardan gyroscope dampers with suitable parameters can effectively decrease the structural vibration in horizontal directions and torsional direction.

VOC-Sensing Properties of Adsorption/Combustion-Type Micro Gas Sensors Using Mesoporous Alumina Co-Loaded with Pt and Metal Oxide

Volatile organic compounds (VOCs), which are generated from adhesives, resins and paints of new building materials and furniture, cause sick house syndrome such as headache, dizziness and nausea, and thus portable VOC-detecting devices with high sensitivity and selectivity were required as an alternative to large and expensive VOC-analyzing systems. Among various types of VOC sensors, adsorption/combustion-type micro gas sensors, which were developed by our group, are quite promising to detect a low concentration of VOCs, because the VOCs, which are firstly adsorbed on the sensing materials at lower temperatures and then the adsorbed ones, are catalytically oxidized at pulsed heating to elevated temperatures leading to a large response to the VOCs. For example, the sensors using Pd-loaded mesoporous (mp-) alumina (Al2O3) exhibited excellent performance in detecting VOCs1), and co-loading of Au with Pd onto mp-Al2O3 by impregnation improved the sensing property to ethanol2). In addition, the ethanol-sensing property was further enhanced by highly dispersing Au(core)/Pd(shell) nanoparticles, which were prepared by ultrasonic-assisted reduction of Au and Pd chlorides with polyethylene glycol monostearate, on the mp-Al2O3 3). Recently, we have demonstrated that the loading of Pt nanoparticles on the mp-Al2O3 by utilizing the ultrasonic-assisted reduction is also effective in improving several VOCs such as ethanol, acetone, and ethyl acetate4). Therefore, VOC-sensing properties of adsorption/combustion-type micro gas sensors using mp-Al2O3 co-loaded with 1 wt% Pt and 10 wt% metal oxide (1Pt/10MO/mp-Al2O3 sensor, MO: metal oxide (Bi2O3, CeO2, Fe2O3, NiO, RuO2 or ZrO2)) have been investigated in this study. The mp-Al2O3 powder (specific surface area: ca. 250 m2 g-1) was prepared by microwave-assisted solvothermal treatment of Al(sec-OC4H9)3 in 1-propanol solution4). The 10 wt% MO-loaded mp-Al2O3 (10MO/mp-Al2O3) powders were prepared by impregnation with the constituent metal salt to the mp-Al2O3 powder, followed by firing at 700ºC for 1 h in air. Thereafter, the mp-Al2O3 and 10MO/mp-Al2O3 powders were loaded with 1.0 wt% Pt nanoparticles, which were synthesized by utilizing the ultrasonic-assisted reduction of H2PtCl6 (10 mM) in deionized water containing an appropriate amount of polyethylene glycol monostearate (MW: 4000). The obtained Pt-loaded powders (1 wt% Pt-loaded mp-Al2O3 (1Pt/mp-Al2O3) or 1 wt% Pt-loaded 10MO/mp-Al2O3 (1Pt/10MO/mp-Al2O3)) and mp-Al2O3 powder were set on the sensing and reference regions of a MEMS platform, respectively, and VOC-sensing properties of the adsorption/combustion-type micro gas sensors were measured with a mode of pulse-driven heating (high temperature (450°C) for 0.4 s after low temperature (150°C) for 9.6 s within a cycle of 10 s). In this operation mode, the target VOCs and/or the partially-decomposed products are adsorbed on the sensing materials at 150°C, and subsequently all the adsorbates abruptly burn upon the pulse heating up to 450°C. Thus, a sensor-signal profile typically consists of one large dynamic response and subsequent static response, which originate from the flash catalytic combustion of these adsorbates and general catalytic combustion, respectively, during the pulse heating at 450°C. The 1Pt/10CeO2-mp-Al2O3 sensor showed the largest static response to all target VOCs (ethanol, ethyl acetate, acetone, benzene, and toluene) among all the sensors tested, probably because Pt/10CeO2-mp-Al2O3 showed the largest specific surface area (ca. 187 m2 g-1). In addition, the magnitude of the static response was little dependent on the kinds of VOCs. On the other hand, all 1Pt/10MO/mp-Al2O3 sensors showed larger dynamic response to ethanol than other VOCs (ethyl acetate, acetone, benzene, and toluene). These sensors also showed relatively large dynamic responses to acetone and ethyl acetate, and the magnitude of dynamic responses to benzene and toluene was much smaller than that to acetone and ethyl acetate. Among them, the 1Pt/10CeO2-mp-Al2O3 sensor showed the largest dynamic response to most of target VOCs, while 1Pt/10Bi2O3-mp-Al2O3 showed the largest dynamic response to only toluene, even though the specific surface area of 1Pt/10Bi2O3-mp-Al2O3 (ca. 142 m2 g-1) is smaller than that of 1Pt/10CeO2-mp-Al2O3. Moreover, the dynamic response speed of the 1Pt/10Bi2O3-mp-Al2O3 sensor to toluene was faster than that of the 1Pt/10CeO2-mp-Al2O3 sensor. These toluene-sensing properties probably result from higher catalytic combustion behavior of toluene over 1Pt/10Bi2O3-mp-Al2O3 than 1Pt/10CeO2-mp-Al2O3. In addition, the adsorption property of toluene on 1Pt/10Bi2O3-mp-Al2O3 may also influence the dynamic response. 1. T. Sasahara, A. Kido, T. Sunayama, S. Uematsu, and M. Egashira, Sens. Actuators, 99, 532-538 (2004). 2. Y. Yuzuriha, T. Hyodo, T. Sasahara, Y. Shimizu, and M. Egashira, Sens. Lett, 9, 409-413 (2011) 3. T. Hyodo, Y. Yuzuriha, O. Nakagoe, T. Sasahara, S. Tanabe, and Y. Shimizu, Sens. Actuators, 202, 748-757 (2014). 4. T. Hyodo, T. Hashimoto, T. Ueda, O. Nakagoe, K. Kamada, T. Sasahara, S. Tanabe, and Y. Shimizy, Sens. Actuators, 220, 1091-1104 (2005).