[en] A strip damage-zone model of the Dugdale-Barenblatt-model type is presented in this paper for analyzing crack growth in ductile materials with damage evolution. In particular, a semi-infinite Mode-1 crack in plane stress or plane strain is considered. The damage is assumed to be present in form of dispersed microvoids, which are localized into a narrow strip direct ahead of a crack-tip. This configuration approximates the real situation naturally arising due to the high stress and strain concentrations in the proximity of the crack-tip. A simple damage model of the Gurson-model type is developed for uniaxial tension to describe the macroscopic properties of the strip damage-zone. Under small-scale yielding and small-scale damage conditions, a system of nonlinear integral equations for the plastic strain and the length of the damage-zone is derived. Numerical results are presented and discussed for the crack opening displacement, the stress and damage distribution within the plastic/damage zone, and the crack resistance curve. Special attention is devoted to reveal the effect of damage evolution on the ductile crack growth

[en] The New SUBARU is a synchrotron light source being constructed at the SPring-8 site. The main facility is a 1.5 GeV electron storage ring that provides light beam in the region from VUV to soft X-ray using SPring-8's 1 GeV linac as an injector. The ring, with a circumference of about 119 meters, is composed of six bending cells. Each bending cell has two normal dipoles of 34 degree and one inverse dipole of -8 degree. The ring has six straight sections: two very long straight sections for a 11-m long undulator and an optical klystron, four short straight sections for a 2.3-m undulator, a super-conducting wiggler, rf cavity and injection, etc. The magnets of the storage ring are composed of 12 dipoles (BMs), 6 invert dipoles (BIs), 56 quadrupoles and 44 sextupoles, etc. For the magnet alignment, positions of the dipoles (the BMs and BIs) are determined by network survey method. The multipoles, which are mounted on girders between the dipoles, are aligned with a laser-CCD camera system. This article presents the methodology used to position the different components and particularly to assure the precise alignment of the multipoles. (authors)

[en] The Crossbar-H mode (CH) structure developed at the IAP in Frankfurt is a multi-cell drift tube cavity for the efficient acceleration of low- and medium-energy ions and protons. A room temperature as well as a superconducting prototype cavity have been developed and tested. These cavities could h used for high-intensity linacs like accelerator-driven systems (AIDS, EUROTRANS) or the international Fusion material irradiation facility (IFMIF). Additionally, the new proton injector for FAIR (324 MHz, 70 mA, 70 MeV) will use room temperature CH cavities. The development of this new type of drift tube cavity and the tests of the prototypes are presented. (authors)

[en] The positron annihilation techniques were used to investigate the quenched-in vacancies and the defects of the thermoelastic martensite transformation in a Cu-base shape memory alloy as well as their behaviors during the martensite aging. Their average positron lifetime τ-bar and the Doppler broadening lineshape parameter S were measured and the relationship between the relative intensity I₂ obtained by three component constrained fit analysis and aging temperature was determined. It suggests that mechanism for the martensite stabilization effect in the alloy should also consider the contribution of martensite transformation defects, particularly the mismatching dislocation on the various interfaces

[en] Objective: Diabetic retinopathy (DR) poses a significant challenge as a leading cause of vision impairment among diabetic individuals. Previous endeavors in optical coherence tomography (OCT) image segmentation using conventional deep learning methodologies have exhibited limitations in achieving robust generalization. Our study endeavors to explore the application of deep transfer learning models on OCT images for DR identification, juxtaposing their performance against conventional deep learning approaches. Methods: Our investigation involved a cohort of 103 DR patients admitted to the ophthalmology department of our institution spanning from January 2023 to January 2024. Through a randomized allocation process, these patients were partitioned into distinct training and validation sets at a ratio of 7:3. Two convolution models, VGG19 and Dense Net, were constructed and transfer learning was carried out. The recognition effect of the traditional model and transfer model is compared and verified. Results: Our findings demonstrate that both the VGG19 and Dense Net prediction models exhibit notable segmentation performance following transfer learning compared to their non-transfer learning counterparts. Post transfer learning, the VGG model achieved accuracy, precision, recall, and F1-score values of 0.890, 0.924, 0.950, and 0.867, respectively, while the Dense Net model achieved corresponding values of 0.897, 0.900, 0.931, and 0.859. Furthermore, in the test set, the area under the curve (AUC) improved significantly for both models post-transfer learning, with the VGG model showcasing an AUC of 0.9118 and the Dense Net model exhibiting an AUC of 0.951. Conclusion: The neural network model leveraging deep transfer learning demonstrates a notable enhancement in the recognition capability of DR based on OCT images. Furthermore, it effectively streamlines the work flow of ophthalmologists, thus warranting further promotion and adoption in clinical practice ophthalmology

[en] This paper reports our recent research works on crack analysis in continuously non-homogeneous and linear elastic functionally graded materials. A meshless boundary element method is developed for this purpose. Numerical examples are presented and discussed to demonstrate the efficiency and the accuracy of the present numerical method, and to show the effects of the material gradation on the crack-opening-displacements and the stress intensity factors.

[en] The polymeric materials could degrade due to the electron irradiation, photo-irradiation and heat effect following with the surface flashover in vacuum. On the other hand, the surface insulating performance could be improved by electron irradiation. In order to study the effect of electron irradiation on the insulating materials, the surface parameters were measured and the flashover experiment was performed in vacuum after electron beam irradiation. First, several typical polymeric samples, such as polytetrafluoroethylene (PTFE), polymethylmethacrylate (PMMA) and polyamide (PA6), were exposed by different energy electron beam from 10 keV to 30 keV and in different radiation times. Then the surface parameters, such as surface topography, chemical group and surface roughness, were measured for insulating samples in different processing conditions. Since the surface trap distribution is closely related to the microscopic structure and defects, the trap parameters of PA6 samples were deduced based on the surface potential data. In this measurement, the polymeric surface was charged by needle-to-plane corona discharge, and then the surface potential was measured by Kelvin electrostatic probe. The surface flashover experiment in vacuum was performed using finger-type plane-electrodes, and the relationship between electron beam energy, irradiation time, and flashover voltage was analyzed. The experiment results indicate that the surface trap energy level is deeper and the trap density is greater after electron irradiation, and the surface flashover voltages for several materials are also improved to different degrees. Combined the macroscopic dielectric parameters with the microscopic one, the effect of electron irradiation on surface insulating property was analyzed. (authors)

[en] Based on the surface piezoelectricity model, the anti-plane or horizontally polarized shear (SH) waves propagating in an infinite piezoelectric plate of nano-thickness are investigated to show the surface effect on wave characteristics. The influence on the overall properties of piezoelectric structures resulting from the surface effect is treated as a spring force exerting on the boundary of the bulk. The frequency equations of anti-symmetric and symmetric waves are presented analytically for the electrically short-circuited case. Numerical results show that the wave properties are size-dependent, and the surface effect becomes very pronounced at a high frequency. -- Highlights: ► We studied the SH waves propagating in a piezoelectric plate with nano-thickness. ► The properties of waves behaviors become size-dependent at nanoscale. ► The results show the effects on the frequency by the surface piezoelectricity.

[en] The bending of multilayer graphene nanoribbons incorporating the effect of interlayer shear is analyzed in this Letter. An improved beam theory is adopted and extended in which the in-plane extension of each layer is also taken into account. The governing equations for bilayer and trilayer graphene nanoribbons subjected to bending are presented as illustrative examples. Exact solutions for cantilever multilayer graphene nanoribbons are derived. Compared with the molecular dynamics (MD) simulations, the present beam model predicts much better results than the previous beam model in which the in-plane extension is ignored. The current study provides a strong evidence to include the in-plane extension effect in the continuum modeling of multilayer graphene structures.

[en] Objective: To explore the effect of Tangshen formula on the oxidative renal injury in UUO mice. Method: Seven-week-old male mice C57BL/6N were selected and randomly divided into sham-surgery group, UUO model group (UUO-7d and UUO-14d), Tangshen formula (TF) group (UUO + TF-7d and UUO + TF-14d) and fosinopril group (UUO + fosinopril-7d, UUO + fosinopril-14d). The model were established after 5d medication, and continuous postoperative medications for 7d or 14d were also carried out. The renal pathology was observed, the MDA concentration and SOD activity of renal tissue and serum were evaluated, along with the expression of NADPH oxidase in renal tissue. Result: Compared with that of sham-surgery group, the inflammatory cells in renal interstitium of UUO mice is characterized by diffuse infiltration and dramatical proliferation of collagen fibers, while the introduction of Tangshen formula helps to alleviate this situation, which decreases MDA concentration (all P < 0.001 for renal tissue and serum) but increases SOD activity (P < 0.001 in renal tissue, P < 0.05 in serum), as well as down-regulates the expression of Nox4 (P < 0.001) and phosphorylated p47phox (P < 0.001) in renal tissue. Conclusion: Tangshen formula alleviates the pathological injury of renal tissue in UUO mice and fibrosis of renal interstitium, the underlying mechanism is relative to the down regulated expression of NADPH oxidase, upon which the oxidative stress level of kidney and serum in UUO mice is decrease