排序方式: 共有7条查询结果,搜索用时 640 毫秒
1
1.
Thitirat Siriborvornratanakul 《Computer-Aided Civil and Infrastructure Engineering》2023,38(16):2300-2316
Because roads are the major backbone of the transportation network, research about crack detection on road surfaces has been popular in computer and infrastructure engineering. When training a convolutional neural network (CNN) for pixel-level road crack detection, three common challenges include (1) the data are severely imbalanced, (2) crack pixels can be easily confused with normal road texture and other visual noises, and (3) there are many unexplainable characteristics regarding the CNN itself. When it comes to very fine and thin cracks, these challenges are exaggerated and a new challenge is introduced, as there can be a discrepancy between the actual width and the annotated width of a crack. To tackle all these challenges of thin crack detection, this paper proposes a new variant of CNN named ThinCrack U-Net, designed to provide thin results upon pixel-level crack detection on road surfaces. The main contribution is to demystify how pixel-level thin crack detection results are affected by different loss functions as well as various combinations of the U-Net components. The experimental results show that ThinCrack U-Net yields a significant performance boost in CrackTree260, from 65.71% to 94.48% F-measure, compared to the existing variant of U-Net previously proposed in the context of pixel-level thin crack detection. Finally, this paper locates the source of undesirable result thickness and solves it with the balanced usage of downsampling/upsampling layers and atrous convolution. Unlike suggested by previous works, different loss functions show no significant impact on ThinCrack U-Net, whereas normalization layers are proved crucial in pixel-level thin crack detection. 相似文献
2.
Thitirat Charoonsuk Taras Kolodiazhnyi Naratip Vittayakorn 《Journal of the American Ceramic Society》2019,102(10):5772-5785
The “top-down” process via direct conversion of the micro (μm)-to-submicroscale (sub-μm) particle was applied in this work by using eutectic chloride salts to prepare BaZrO3. The particle size at optimum condition could be decreased by more than 10 times from 2.1 ± 0.9 μm to 168 ± 23 nm without destroying the 1:1 of Ba:Zr stoichiometry. The uniform sub-μm-BaZrO3 powder was sintered in order to obtain ~98% dense ceramic at 1400°C/10 h, which is significantly lower than the 1650°C in normal cases. The microwave dielectric constant, tan δ, and quality factor were also determined. Furthermore, this method also was applied to lead-free piezoelectric material in the 0.87BaTiO3–0.13BaZrO3–CaTiO3 (0.87BT–0.13BZ–CT) system. The particle size of 0.87BT–0.13BZ–CT was reduced greatly from >10 µm to 2.8 ± 0.4 µm. It can be proved that salt flux dissolution method enables high-purity with uniform sub-micro/nanometer powder production in one step by using simple laboratory equipment and low-cost raw materials. 相似文献
3.
CaTiO3 induced ferroelectric phase coexistence and low temperature dielectric relaxation in BaTiO3–BaZrO3 ceramics 下载免费PDF全文
Manoon Sutapun Thitirat Charoonsuk Taras Kolodiazhnyi Naratip Vittayakorn 《Journal of the American Ceramic Society》2018,101(5):1957-1966
The series of 0.86BaTiO3–(0.14?x)BaZrO3–xCaTiO3 (abbreviated as BT–BZ–xCT) ceramics with 0.03 ≤ x ≤ 0.11 were studied to obtain high piezoelectric properties. Rietveld refinement analysis indicated that the BT–BZ–CT compositions follow a gradual rhombohedral (R) → orthorhombic (O) + R → O + tetragonal (T) → T phase transformation with increasing x. Clear evidence of the series of ferroelectric phase transitions was also found in the dielectric results. The R‐O and O‐T transition temperature shifted close to ambient temperature, while the Curie temperature slightly increased with increasing x. In addition to the dielectric loss peaks associated with the structural phase transitions, a broad low‐temperature dielectric loss peak was detected in the R phase at T = 90‐150 K. This dielectric relaxation was attributed to the domain wall freezing and fits well to the Vogel‐Fulcher model with activation energy Ea ≈ 60‐300 meV and freezing temperature TVF ≈ 75‐140 K. High piezoelectric strain coefficient (d33*) of about 1030 pm/V at 10 kV was achieved at x = 0.07, and a high Curie temperature (TC) was maintained at about 375 K. 相似文献
4.
AbstractDielectric properties of nanocrystalline barium zirconate titanate (Ba(ZrxTi1-x)O3; BZT for x?=?0.1 and 0.3) synthesized by glycine-nitrate autocombustion method were investigated in this study. The phase formation examined by TGA-DTA, XRD, FT-IR and Raman spectroscopy confirmed that high purity single-phase BZT with perovskite structure was obtained by using glycine-to-nitrate molar ratio of 2.2:4 and calcining in air at 1100?°C for 4?h. TEM analysis showed that BZT had agglomerate particles consisted of primary spherical nanocrystals with the size of 8-11?nm. The diffuse phase transition behavior of BZT ceramics increased with increasing Zr concentration and for x?=?0.3, the Curie temperature; Tc, shifted to below room temperature. The BZT ceramics for x?=?0.1 had relatively high dielectric constant (ε), 13007, low Tc, 76?°C and comparable dielectric loss (tan δ) at Tc, 0.012 which caused by the high degree of Zr diffuseness into the perovskite structure. These results suggest that glycine-nitrate autocombustion is the effective method for preparing high quality BZT ceramics. 相似文献
5.
Piyanut Charoonsuk Wanwilai Vittayakorn Rangson Muanghlua Banjong Boonchom Surasak Niemcharoen Naratip Vittayakorn 《Ceramics International》2013
The perovskite phase formation of nanocrystalline powder of lead zirconate (PbZrO3, PZ) was investigated. The structure, phase formation and morphology of PZ powders were characterized using the X-ray diffraction technique (XRD), Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, transmission electron microscope (TEM) and differential scanning calorimetry (DSC). Tetragonal zirconia (t-ZrO2) phase was found as an intermediate phase during the calcinations process, followed by the crystallization of the orthorhombic PZ phase. The change in relative amount of the residual t-ZrO2 phase as a function of calcination temperature was estimated from the relative intensities of selected Raman peaks. From a TEM photograph, the PbZrO3 powder was found to be spherical in shape with uniform nanosized features. The average particle size for the calcined powders was about 10.44±1.21 nm. 相似文献
6.
Pisutsaran Chitichotpanya Thitirat Inprasit Chayanisa Chitichotpanya 《Journal of Natural Fibers》2019,16(1):88-99
The environmental-friendly, economical, and simple one pot formulation for enhanced antibacterial and mechanical property finishing on medical cotton fabrics was successfully developed and optimized using a central composite design in conjunction with response surface methodology. It combines the concepts of in situ synthesis of AgNPs and photocatalytic property of TiO2 in waterborne polyurethane as the finishing emulsion without additional organic reducing or stabilizing agent. The optimal formulation with contents of AgNO3 (240 ppm) and TiO2 NPs (980 ppm) exhibited excellent antibacterial activities against Klebsiella pneumoniae and Staphylococcus aureus with over 99% reduction and improved mechanical properties as well as non-toxicity to mammalian cells. 相似文献
7.
Phase Formation,Microstructure, and Densification of Yttrium‐Doped Barium Zirconate Prepared by the Sonochemical Method 下载免费PDF全文
Panpailin Seeharaj Thitirat Charoonsuk Patchara Pasupong Pattaraporn Kim‐Lohsoontorn Naratip Vittayakorn 《International Journal of Applied Ceramic Technology》2016,13(1):200-208
Spherical monodispersed yttrium‐doped barium zirconate (BaY0.1Zr0.9O3; BYZ) particles were successfully prepared in single step without the requirement of calcination process by the sonochemical method in highly basic aqueous solution. The stoichiometric solution of BaCl2.2H2O, ZrOCl2.8H2O, and YCl4.6H2O was precipitated in a 20 M NaOH under high‐intensity ultrasonic irradiation (20 kHz, 150 W/cm2) for 15, 30, and 60 min. As‐prepared powders were identified by XRD, FT‐IR, and Raman spectroscopy as cubic perovskite BYZ. The microstructure examined by SEM and TEM showed spherical‐shaped BYZ particles formed by aggregation of primary nanocrystals, and this unique morphology was induced by the effects of the ultrasonication and the strong alkaline environment. BYZ powders prepared under ultrasonication for 60 min had narrow‐sized distribution with the average particle size of 267 ± 26 nm and the specific surface area of 40.2 m2/g. BYZ ceramics sintered in the air at 1550°C for 20 h showed good densification (95%) and consisted of large grain size (7.67 ± 2.79 μm). 相似文献
1