Application of encapsulated hollow Gold nanocluster targets for high-quality and quasi-monoenergetic ions generation

With persistent progress in ultra-intense laser pulses, Coulomb explosion (CE) of spherical nanoclusters can in principle produce high-quality-quasi-monoenergetic ions. Focusing on using CE framework, in this paper, we have proposed a target scheme to accelerate light/heavy ions’ beam. The scheme relies on encapsulating a hollow Gold nanocluster inside a hollow proton-Carbon (HC) nanosphere. The ability of this suggestion has been simulated by the two-dimensional particle-in-cell code (EPOCH). Simulation results exhibit that a hollow Gold cluster can positively increase the electrons’ extraction. This condition may improve the acceleration of low-divergence H+, C6+, and Au67+ ions. Our simulation shows that at the end of the interaction, for a Gold cluster with an optimal hollow radius of 91.3 nm, the cut-off energy of H+, C6+, and Au67+ are about 54.9 MeV/u, 51.5 MeV/u, and 54.9 MeV/u, respectively. In this case, an increase of about 52% for H+ and 61% for C6+ is obtained, contrast to bare HC hollow nanosphere (i.e., a hollow nanosphere with no cluster), while the relative divergence decreases to 1.38 and 1.86, respectively for H+ and C6+ ions. We have also compared our simulation results with another proposed target structure composed of a void area with an optimum diameter of 70.4 nm between the fully- Gold nanocluster and HC nanosphere. We have exhibited that the results are improved, contrast to bare nanosphere. However, the cut-off energy suppression and angular divergence increase are shown compared with encapsulated hollow Gold nanocluster structure.

Dimensions and Forms of Artefacts in 1.5T and 3T MRI Caused by Cochlear Implants

Introduction:Cochlear implantation is a standard treatment option due to expanding indicationsCranial magnetic resonance imaging (cMRI) has become a widespread diagnostic tool. Therefore, an increased number of cochlear implant (CI) users are undergoing cMRI scans.This study aimed to investigate the issue of the CI magnet impacting MRI quality and artifacts.Material and Methods:1.5T and 3T MRI scans with 4 defined sequences (T2-TSE, T2-TIRM, T1-3D-MPRAGE, and TDI) were performed on a phantom with a CI (Synchrony® System by MEDEL Austria®) in place. The resulting MRI artifacts were retrospectively compared to MRI artifacts observed in patients with a CI. All images were transferred to Amira® and visualized by manual segmentation.Results:Usable image quality was achieved in three sequences(T2-TSE, T2-TIRM and T1-mprage). Observed artifacts differed in shape and size depending on the sequence. Maximum diameters of fully extinguished areas ranged from 58x108x98 mm to 127x123x153 mm. Image distortions were larger.Conclusion:MRI artifacts caused by the Synchrony® system are asymmetric with varying shape, depending on the sequence. The phantom artefacts are similar to those in CI users. Considering the observed asymmetry, the hypothesis of varying implantation locations resulting in varying positions of the signal void area needs to be further investigated.

EVALUATION OF ROOT CANAL OBTURATION RESULTS WITH THE CANAL SHAPING SYSTEM WAVE ONE AND GUTTA THERMAFIL

Objective: To evaluate the results of root canal obturation with Wave One (WO) canal shaping system and Gutta Thermafil obturation system. Design: Nonrandomized prospective experimental trial between December 2020 and March 2021. Setting: Central Military Hospital 108. Subject: 30 lower incisors extracted teeth without stem rupture, without root damage such as fracture, stray, fissure. Results: The number of slices with the biggest gaps accounting for 16.7%. The number of slices with the smallest gaps accounting for 10%. The number of slices with gaps over the total slices accounted for 14.4%. The void area in the apical slice was 1,413 ± 519.5 µm2 and the largest void area was 38,654.2 ± 3,939.8 µm2. Conclusion: Thermafil Gutta Percha has a good fit to the canal wall, which can seal the canal more easily and accurately.

Integrative analysis of the choroid by quantifying Haller vessel and choriocapillaris parameters in different drusen subtypes

This study aimed to quantify the Haller vessel and choriocapillaris (CC) parameters in drusen subtypes in nonexudative age-related macular degeneration (AMD) and pachydrusen. Ninety-five eyes of 80 patients and 28 control eyes were categorized into soft drusen, subretinal drusenoid deposit (SDD), soft drusen plus SDD, pachydrusen, and control groups. The diameter, length and intersections of Haller vessels and the total area, size and number of CC flow voids were quantified using en face optical coherence tomography (OCT) or OCT angiography. The pachydrusen group showed the largest Haller vessel area and diameter and shortest total length but similar CC parameters to those in the control group. The soft drusen plus SDD group showed the largest CC flow void area and size, while the Haller parameters were similar to those in the control group. The area and size of the flow voids in the SDD group were smaller than those in the soft drusen plus SDD group. Based on unsupervised machine learning, the eyes were classified into 4 clusters—the control, pachydrusen, soft drusen plus SDD and soft drusen plus SDD groups. Cluster 3 showed a larger diameter and shorter total length of the Haller vessels than cluster 4.

Effect of Wood Flour Addition on Warm/Cool Feeling of Green Composite

In this study, effect of wood flour addition on warm/cool feeling of green composite using wood flour and poly(lactic acid) was investigated for comfortability of interior product. Additive amounts of wood flour were 10 – 40 wt.%. Measurement of initial maximum values of heat flux of green composite using wood flour was conducted under constant temperature and humidity chamber. Surface of green composite using wood flour was observed by Scanning Electron Microscope (SEM). Following conclusions were obtained. The initial maximum value of heat flux of green composite decreased with an increase of wood flour additive amount until 20 wt.%. But, initial maximum value of heat flux of green composite at more than wood flour additive amount 30 wt.% almost did not change. From SEM observation, the appearance void area on surface of green composite at wood flour additive amount 20 wt.% was larger than that of green composite at wood flour additive amount 10 wt.%. Therefore, initial maximum value of heat flux of green composite was mainly affected because of increase of void area and wood flour until wood flour additive amount 20 wt.%.

Temperature Field Variation Law of Low Exothermic Polymer Grouting Material in Repairing Void Damage of Frozen Soil Subgrade

In this study, the self-developed grouting mold was used to study the heat release characteristics of different density polymer grouting material under different temperature conditions. The spatial distribution characteristics of the frozen soil subgrade temperature field under the effect of polymer grouting repair were analyzed. Further, the rules governing the temperature change of a frozen soil subgrade monitoring point under the effect of polymer grouting repair were studied. The heat transfer mechanism of polymer grouting material in frozen soil subgrade was revealed. The results showed that in the void region of the frozen soil subgrade, a discontinuity zone appeared in the temperature field distribution isotherm due to the effect of voids; this zone exhibited a layered radioactive distribution along the two sides of the void area. Furthermore, during the exothermic stage of the curing reaction, the temperature distribution isotherms changed from a layered radioactive distribution to a ring distribution that decreased from the inside to outside. During the natural cooling process, the peripheral temperature of the ring isotherm first decreased and a negative temperature ring-shaped isotherm gradually formed. Finally, the upper boundary of the influence of the heat energy released by the curing reaction on the frozen soil subgrade temperature field was determined to be 30 cm, and the lower boundary was 20 cm.

Studying Bump at Bridge Approach of Short Subgrade with Oblique Prestressed Concrete Overlaying Asphalt Layer

The differential settlement of short subgrade between two highway structures (bridges, tunnels, culverts, etc.) is significantly greater than that of the other subgrade for the insufficient compaction of short subgrade owing to limited construction site. This paper aims to establish the control criteria to prevent bump at bridge approach for differential settlement of short subgrade with oblique prestressed concrete overlying asphalt layer (AC + OPC) composite pavement. In this work, the short subgrade and AC + OPC composite pavement were defined. Meanwhile, the driving comfort was analysed and the control criteria for differential settlement of short subgrade with different lengths were obtained based on the driving comfort using the driving comfort test. Finally, the effects of different layer parameters on stress and deflection were investigated and the control criteria for differential settlement of short subgrade were established based on the void area beneath the slab using the finite element software ANSYS. Results show that the length of short subgrade between two highway structures is defined to be less than 200 m. The vehicle speed and longitudinal slope have significant effects on the vertical acceleration. The asphalt layer modulus, OPC layer thickness and modulus, base layer thickness and modulus, and foundation modulus have effects on the flexural stress and deflection, especially the OPC layer thickness. The relationship between the additional stress and void area beneath the slab is derived. In addition, the control criteria for differential settlement of short subgrade with different lengths are put forward based on the void area beneath the slab and driving comfort. The application of AC + OPC composite pavement can prevent bump at bridge approach of short subgrade effectively. The results of this paper can provide guidance for the application of AC + OPC composite pavement.

Study on microstructure influence mechanism to mechanical behavior of OGFC asphalt mixture

Microstructure characteristics of OGFC (open graded friction course) asphalt mixture are closely related to the mechanical behavior. To study the microstructure influence mechanism to mechanical behavior of OGFC asphalt mixture, the digital image processing technology is used to process the specimen’s fault images and obtain the microstructure parameters of the OGFC asphalt mixture with different gradation. At the same time, the microstructure influence on mechanical behavior of OGFC asphalt mixture is explored by using the Grey correlation theory based on the experimental results of mechanical performance and the microstructure parameters. The influence of four key sieve passing percentage (1.18, 2.36, 4.75, and 9.5 mm) on the microstructure was discussed by using the Grey correlation theory, and the influence mechanism to mechanical behavior of OGFC asphalt mixture was further revealed. The results show that with the increase of air void content, the total void area, the equivalent pore diameter, and the number of big voids (here, “big” means voids with an area greater than 10 mm2) increase, the length of void and corresponding void area increase synchronously, the drainage performance is enhanced, and the mechanical performance is decreased. With the increase of nominal maximum particle size, the average area of single void, the percentage of number of big voids, and the equivalent diameter increase, and the drainage performance, anti-skidding performance, and mechanical performance of pavement are enhanced. It is considered that the key sieve passing percentage affects the mechanical behavior by influencing the microstructure of asphalt mixtures. The influence degree of microstructure parameters on mechanical behavior and the influence degree of the key sieve passing percentage on microstructure parameters were obtained. The research results have a certain reference value for the optimization of mechanical behavior of OGFC asphalt mixture.