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To reveal the failure mechanism of fractured sandstone under the influence of the infilling material strength, uniaxial compression tests, and PFC3D numerical simulation analyses were conducted on fractured sandstone with different infilling material strengths, and the influence of the infilling material strength on the basic mechanical properties of the fracture‐filled sandstone was studied. The results showed that, with increasing infilling material strength, the peak strength and elastic modulus of the specimens increased nonlinearly and eventually stabilized. The failure pattern of the specimens changed from shear to tensile. When the infilling material strength was low, a wing crack or anti‐wing crack was generated; however, when the infilling material strength was high, a vertical tensile crack was generated. From the perspective of fracture mechanics, the filling of sandstone cracks can reduce or even suppress the stress concentration effect at the prefabricated crack tip and improve the bearing capacity of the fractured sandstone. Highlights: The basic mechanical properties of the fracture‐filled sandstone specimens were obtained.PFC3D numerical simulation analyses were conducted on fractured sandstone.The influence mechanism of filling materials on the fractured rock was revealed. [ABSTRACT FROM AUTHOR]

Obtaining the bursting liability is essential for rock burst mitigation. To reasonably evaluate the bursting liability of coal in deep coal mining, a new modified bursting energy index considering rebound and damage effects of rock is proposed. Then, uniaxial compressive tests of gypsum–rock combination specimens with different rock types are conducted for researching the energy evolution and bursting liability. Third, the traditional bursting energy index KE and modified bursting energy index KED are compared. At last, the reasonability of KED is verified through PFC2D simulation. Results show: (1) When evaluating the bursting liability of coal–rock combination, the rebound and damage effects of rock must be considered. (2) The uniaxial compressive strength of gypsum–rock combination specimen nonlinearly increases with increasing rock strength, but the dynamic failure duration exponentially decreases. (3) KE and KED all increase linearly when the rock strength increases. (4) The slope of fitting curve of KED is smaller than that of KE, indicating that the bursting liability calculated by KE is strengthened. (5) PFC2D simulation shows that KED decreases with increasing number of drilling hole in the coal component. When using KED to evaluate the bursting liability of coal–rock combination, it is more reasonable and applicable. [ABSTRACT FROM AUTHOR]

Purpose. To evaluate the prevalence and causes of visual impairment in a group of community people with type 2 diabetes mellitus (T2DM) in Northeast China. Methods. Population-based cross-sectional survey. Patients diagnosed with T2DM residing in 15 communities in Fushun, Northeast China, were enrolled between July 2012 and May 2013. All participants underwent an extensive and standardized eye examination (visual acuity testing, slit-lamp, and fundus examination). Low vision was defined as presenting VA of better-seeing eye <20/60 and ≥20/400, and blindness was defined as VA <20/400, according to the World Health Organization (WHO) definitions. The primary causes of blindness and low vision were assessed by senior ophthalmologists. Results. Visual acuity measurements were available for 1998 (89.8%) of 2224 subjects in the study. The prevalence of bilateral blindness and low vision defined was 0.90% and 10.81%. Uncorrected refractive error was the first leading cause of low vision (75.0%) and blindness (38.9%). After correcting the refractive error, the first leading cause of low vision was cataract (44.4%), followed by diabetic retinopathy (29.6%) and myopic maculopathy (18.5%), while the first leading cause of blindness was proliferative DR (45.4%), followed by cataract (36.4%) and myopic maculopathy (18.2%). Conclusions. This study suggested a high prevalence of low vision and blindness in this study cohort. Uncorrected refractive error and cataract remain the leading cause of visual impairment, but the major challenge is the early diagnosis and intervention of diabetic retinopathy to reduce diabetes-related blindness. [ABSTRACT FROM AUTHOR]

This letter demonstrates a possibility to overcome the polarization-dependent problem in surface enhanced Raman scattering (SERS) performance by two-dimensional (2D) sinusoidal silver grating. A reproducible SERS substrate with a large area can be easily fabricated by maskless laser interference photolithography. The polarization-independent SERS performance and SERS enhancement factor (EF) of this substrate are deduced by finite difference time domain and demonstrated by R6G SERS detection experiments. SERS performance of 2D sinusoidal grating is polarization-independent over the whole 360° and EF can be 5 orders of magnitude as possible. Moreover, this long-range SERS substrate can realize label-free SERS detection of 2,4,6-Trinitrotoluene (TNT). [ABSTRACT FROM AUTHOR]