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The crack initiation load of freshly fractured surfaces for silica glass was evaluated with ball indentation. The fracture surfaces were formed during subcritical crack growth in the regions I, II, and III of the stress intensity factor (KI)—crack velocity (V) curve. From the KI–V curve, we linked the obtained fracture surfaces with the ones in the regions I, II, and III. It was found that the crack‐forming probability was the lowest for the fracture surface formed in the region III of the KI–V curve. In order to understand the controlling factors of the crack formation, some properties which are topography, relative nonbridging oxygens (NBO), hydrogen concentrations, and Si–O three‐ or four‐membered ring structures, of the fracture surfaces were measured by atomic force microscopy, X‐ray photoelectron spectroscopy, dynamic secondary ion mass spectroscopy, and Raman spectroscopy, respectively. No distinct difference in NBO and hydrogen concentrations nor the ring structures were found among the fracture surfaces formed in different regions in the KI–V curve. The peak‐to‐valley height of the fracture surface, however, decreased with increasing crack velocity. It is concluded that the roughness or topography of the freshly fractured surface is one of the controlling factors which reduce the intrinsic strength of silica glass. [ABSTRACT FROM AUTHOR]

Ammonia temperature-programmed desorption with water vapor treatment and theoretical analysis is used to determine the acidic property of sulfated zirconia. Two types of acid sites are generated, one being Lewis type generated on a submonolayer species of the sulfate covering the surface and the other type of acid site generated by loading excess sulfate possessing a high concentration.

The mixed alkali metaphosphate glass of 16.7Li2O‐16.7Na2O‐16.7K2O‐50P2O5 (in mol%, (Li,Na,K)PO3) showed large birefringence (significant anisotropy) due to highly oriented ‐P‐O‐P‐ chains when the glass was deformed under uniaxial tensile stress above glass transition temperature (Tg). To investigate structural features causing the significant anisotropy, 31P magic‐angle spinning nuclear magnetic resonance (MAS NMR), Raman, and Fourier‐transform infrared spectra of alkali metaphosphate glasses were analyzed. In the (Li,Na,K)PO3 and the 50Na2O‐50P2O5 (NaPO3) glasses, which have comparable force constant between alkali cation and oxygen (FM‐O), the number of Q2 units in ‐P‐O‐P‐ chains was equivalent. On the other hand, various types of alkali cations in the (Li,Na,K)PO3 glass result in larger distribution of FM‐O compared to the NaPO3 glass. Therefore, formation of the significant anisotropy for the (Li,Na,K)PO3 glass results from orientation of local structures with small FM‐O during suppression of shear flow between chains by local structures with large FM‐O. [ABSTRACT FROM AUTHOR]

Background: Using conventional computed tomography (CT), the accurate diagnosis of lymph node (LN) metastasis of esophageal cancer is difficult.Purpose: To examine dual-energy CT parameters to predict LN metastasis preoperatively in patients with esophageal cancer.Material and Methods: Twenty-six consecutive patients who underwent dual-energy CT before an esophageal cancer surgery (19 patients with LN metastases) were analyzed. The included LNs had a short-axis diameter of ≥4 mm and were confirmed to be resected on postoperative CT. Their short-axis diameter, CT value, iodine concentration (IC), and fat fraction were measured on early- and late-phase contrast-enhanced dual-energy CT images and compared between pathologically confirmed metastatic and non-metastatic LNs.Results: In total, 51 LNs (34 metastatic and 17 non-metastatic) were included. In the early phase, IC and fat fraction were significantly lower in the metastatic than in the non-metastatic LNs (IC = 1.6 mg/mL vs. 2.2 mg/mL; fat fraction = 20.3% vs. 32.5%; both P < 0.05). Furthermore, in the late phase, IC and fat fraction were significantly lower in the metastatic than in the non-metastatic LNs (IC = 2.0 mg/mL vs. 3.0 mg/mL; fat fraction = 20.4% vs. 33.0%; both P < 0.05). Fat fraction exhibited accuracies of 82.4% and 78.4% on early- and late-phase images, respectively. Conversely, short-axis diameter and CT value on both early- and late-phase images were not significantly different between the metastatic and non-metastatic LNs (P > 0.05).Conclusion: Using dual-energy CT images, IC and fat fraction are useful for diagnosing LN metastasis in patients with esophageal cancer. [ABSTRACT FROM AUTHOR]