Surface Projection Research Articles

Experimental Investigations of Ni-Ti-Ru System: Liquidus Surface Projection and 1150 °C Isothermal Section.

Ruthenium addition inhibits the formation of the topologically close-packed phases in Ni-based superalloys and improves the solid solution strength of Ni-Ti shape memory alloys. Therefore, the Ni-Ti-Ru phase stability is a very valuable indicator of the effects of Ru in Ni-based superalloys and Ni-Ti shape memory alloys. In this study, the isothermal section at 1150 °C and liquidus surface projection of the Ni-Ti-Ru ternary system were determined experimentally using the equilibrated alloy method and diffusion couple method, respectively. Alloys were prepared through the arc-melting of Ni, Ti, and Ru (all 99.99% purity), and then vacuum encapsulation in quartz tubes, followed by annealing at 1150 °C for 36 to 1080 h depending on the alloy composition. Diffusion couples were fabricated by joining one single-phase block (τ1) with one two-phase block (Ni3Ti + γ(Ni)), and the couples were annealed under vacuum at 1150 °C for 168 h. Reaction temperatures of as-cast alloys were determined by differential scanning calorimetry performed with heating and cooling rates of 10 °C/min. Scanning electron microscopy and X-ray diffraction were used to analyze the microstructure. Seven three-phase regions were found at the 1150 °C isothermal section. Seven primary solidification regions and five ternary invariant reactions were deduced in the liquidus surface projection. A new ternary compound τ1 was discovered in both the isothermal section at 1150 °C and liquidus surface projection. The results aid in thermodynamic modeling of the system and provide guidance for designing Ni-based superalloys and Ni-Ti shape memory alloys.

Poster 141: Does the Traditional TT-TG Distance Accurately Reflect the Relative Position of the Tibial Tubercle to the Trochlear Groove? A Three-Dimensional Analysis

Objectives: The tibial tubercle to trochlear groove (TT-TG) distance often guides surgical decision- making for patellar instability. Traditional TT-TG measurements are limited by interrater reliability and lack of consideration for variable anatomy throughout flexion. The purpose of this study was to compare the traditional TT-TG measurement to three-dimensional measures generated from automated trochlear groove detection with sequential radial slices on magnetic resonance imaging (MRI). Methods: Twenty-four knees (4 healthy controls, 20 patellar instability patients) were segmented into three-dimensional distal femur and tibia models. A custom-designed program was employed to detect the trochlear groove through its course based on the shortest distance to the origin in a polar (radial) axis defined by the distal femoral condyles. The program also identified the surface projection of the tibial tubercle center of mass. The medial-lateral distance between the trochlear groove and tibial tubercle was calculated for the first 45 degrees of the detected groove to generate radial TT-TG (rTT-TG) values. The mean and maximum rTT-TG values were compared to the traditional TT-TG MRI measurement performed by one grader. Results: Mean rTT-TG values were significantly greater than traditional measurements (21.8 mm versus 17.9 mm, p=.003) with moderate correlation between measurements (Pearson r = 0.59, p=.002). In Dejour C and D dysplasia, the mean rTT-TG measurements trended towards being greater than traditional measurements (C: 24.3 mm versus 16.6 mm; D: 28.5 mm versus 21.8 mm; p=0.057 for both comparisons). Dejour C dysplasia demonstrated a significantly greater maximum rTT-TG than the traditional measurement (27.9 mm versus 16.6 mm, p=0.029), and Dejour D dysplasia demonstrated a similar trend (30.2 mm versus 21.8 mm; p=0.057). Conclusions: Traditional TT-TG distances may underestimate the true medial-lateral offset between trochlear groove and tibial tubercle, particularly in patients with high- grade dysplasia. This represents a potential alternative to the current standard measurement techniques which may improve measurement reliability by automation. Our study suggests that utilizing 3D radial TT-TG values via automated measurement may more accurately portray the variable anatomy of the trochlear entrance and offer a standardized alternative to a frequently used measurement to overcome reader reliability.

Analytical and computer modeling of surfaces with the curvilinear projection method

The article discusses the shaping of surfaces by analytical methods and their visualization by means of computer graphics. This topic attracts the attention of architects, engineers and mechanical scientists, for whom it is important to see the surfaces in the structures of machines for various purposes and in the forms of structures, to approximate complex surfaces with simpler ones - analytical ones; choose a rational form of the shell from several options, taking into account the functional, technological and ergonomic requirements for the product. The purpose of the work is to study the methods of formation of surface shapes. The research method is the general analytical theory of applied surface shaping, which meets modern requirements for the use of computer technology. In this paper, parametric equations of the cyclic surface of Joachimsthal are obtained, the possibilities of shaping such surfaces, which are recommended for practical use, are shown. Using examples of visualization of surfaces by means of computer graphics (Maple program), the use of analytical models is shown, which makes it possible to quickly and reliably assess the constructive and aesthetic qualities of the shell in scientific research, design, and manufacture. The ways of developing an analytical apparatus are determined, which allows modeling the process of curvilinear projection and the formation of surfaces as a system of projecting rays passing through a given surface projection. The purposeful choice of the parametric form of analytical modeling of surfaces contributes to the direct use of models in automated design systems, pre-production systems and in modern computer graphics packages (Kompas 3D, Renga, Revit, Ansys, Lira Sapr, Scad, etc.).

Dy–Al–Si System: Experimental Study of the Liquid–Solid Phase Equilibria in the Al-Rich Corner

The Dy–Al–Si ternary system has been experimentally studied, as the effect of the dysprosium addition on the constitution and topology of the liquidus surface, focusing on the (Al) rich part. The system has been investigated in a composition range of up to about 58 at% silicon. The alloys constitution and the liquidus surface projection have been determined by means of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDXS), X-ray powder diffraction (XRPD), and differential thermal analysis (DTA). This work is part of a research framework on the properties and solid–liquid phase equilibria of the R Al–Si (R: rare earth) systems. These data, along with the ternary systems isothermal section, are needed to outline the design, plan, and development of new Al–Si-based alloys. In the Dy–Al–Si system, four primary crystallization fields have been experimentally detected: (Si), DyAlxSi(2−x) (orthorhombic form), Dy2Al3Si2 (Τ2), and DyAl(3−x)Six. The following three invariant equilibria have been identified: at 566 °C the ternary eutectic L ⇆ DyAl2Si2 + (Al) + (Si), at 630 °C the U1 L+ DyAl3 ⇆ Dy2Al3Si2 + (Al), and at 562 °C the U2: L+ Dy2Al3Si2 ⇆ DyAl2Si2 +(Al) reactions. A comparison with other known R Al–Si systems has been conducted.

Critical Evaluation and Thermodynamic Re-Optimization of the Si-P and Si-Fe-P Systems.

Thermodynamic modeling of the Si-P and Si-Fe-P systems was performed using the CALculation of PHAse Diagram (CALPHAD) method based on critical evaluation of available experimental data in the literature. The liquid and solid solutions were described using the Modified Quasichemical Model accounting for the short-range ordering and Compound Energy Formalism considering the crystallographic structure, respectively. In the present study, the phase boundaries for the liquidus and solid Si phases of the Si-P system were reoptimized. Furthermore, the Gibbs energies of the liquid solution, (Fe)3(P,Si)1, (Fe)2(P,Si)1, and (Fe)1(P,Si)1 solid solutions and FeSi4P4 compound were carefully determined to resolve the discrepancies in previously assessed vertical sections, isothermal sections of phase diagrams, and liquid surface projection of the Si-Fe-P system. These thermodynamic data are of great necessity for a sound description of the entire Si-Fe-P system. The optimized model parameters from the present study can be used to predict any unexplored phase diagrams and thermodynamic properties within the Si-Fe-P alloys.

Phase equilibra in the Ag2S–Ag8GeS6–Ag8SiS6 system and some properties of solid solutions

Phase equilibria in the Ag2S–Ag8SiS6–Ag8GeS6 system were studied using differential thermal analysis and powder X-ray diffraction technique. Boundary section Ag8SiS6 – Ag8GeS6, liquidus surface projection, an isothermal section of the phase diagram at 300 K, and some polythermal sections of the studied system were constructed. The formation of continuous series of solid solutions between both crystalline modifications of the starting compounds was determined in the Ag8SiS6–Ag8GeS6 system. The liquidus surface of the Ag2S–Ag8SiS6–Ag8GeS6 system consists of two fields corresponding to the primary crystallization of the high-temperature modifications of the HT-Ag8Si1-xGexS6 and HTAg 2S phases. Lattice parameters for both modification of solid solutions were calculated based on powder X-ray diffraction data. The concentration dependence of lattice parameters obeys Vegard’s rule. The obtained new phases are of interest as environmentally safe materials with thermoelectric properties and mixed ionelectron conductivity

Maximum isotope accumulation in the retrosplenial cortex during amnesia attack and its temporal change suggest cortical spreading depression as a pathophysiology of patients with transient global amnesia

AbstractTransient global amnesia (TGA) is a clinical syndrome that is characterized by the sudden onset of anterograde amnesia and a less prominent impairment in retrograde memory lasting up to 24 h. Although several etiologies have been proposed, including migraine, epilepsy, ischemia, venous congestion, and glutamate toxicity, none sufficiently explain the disorder in its entirety. We retrospectively investigated images obtained using single‐photon emission computed tomography (SPECT), performed with 99mtechnetium hexamethylpropyleneamine oxime, from 11 patients with TGA divided into the following groups based on the timing of SPECT: during TGA (n = 2, Group 1), at the start of the attenuation of memory impairments (n = 2, Group 2), and after TGA (n = 7, Group 3). Regional isotope accumulation was examined using a three‐dimensional stereotactic surface projection (3D‐SSP) analysis. After calculating the mathematical product of the mean severity and extent ratio, unique comparable bar graphs were prepared with respect to Brodmann's areas (B). Increases in isotope accumulation were the largest in the retrosplenial cortex (B29, B30), posterior cingulate cortex (B23, B31), and precuneus (B7) in Groups 1 and 2, whereas decreases were noted in the same regions in Group 3. This is the first study to identify cerebral sites and describe changes consistent with the completion of amnesia as a symptom using an image analysis, such as a 3D‐SSP analysis. We consider cortical spreading depression (CSD) to be the etiology of TGA based on maximum isotope accumulation in the above sites and a literature review on CSD.

Constraints on ground deformation processes at the Tulu Moye volcanic complex, Main Ethiopian Rift

Tulu Moye is an actively deforming volcanic complex with a geothermal field in the Main Ethiopian Rift. We use InSAR between 2014 and 2022, integrated with other geophysical data, to investigate the temporal and spatial characteristics of the deformation signal in the area, and to model its source. Velocity maps and time series analysis show a deformation signal consistent with uplift at a velocity of up to 50 mm/yr in the satellite Line-of-Sight (LOS) in 2014–2017, then decreasing to 12 mm/yr until 2022. The centre of deformation is located about 10 km west of a main geothermal drilling site at Tulu Moye, between the Bora, Berecha, and Tulu Moye volcanoes, with a NW-SE elongation direction. Our best-fit model suggests that the deformation is caused by an 8.7 km by 1.2 km sill situated ∼7.7 km below the surface (∼5.9 km below sea-level), elongate in the N54°W direction and dipping S11°W, and experienced an average velocity of volume change of ∼8.9 × 106 m3/yr in 2014–2017. The surface projection of the sill overlaps with local transverse faults and hydrothermal manifestations. The sill is ∼1–2 km below clusters of microseismic swarms and a region of high resistivity, both indicating hydrothermal fluid flow. The location and geometry of the sill correlates with the upper edge of high conductivity interpreted as a zone of partial melt, and we therefore attribute the uplift at the Tulu Moye volcanic complex to inflow of magma in the sill. We also suggest that the transverse caldera rims faults may restrict magma flow, and also facilitate both vertical and lateral hydrothermal fluid flow.

Assessment of the Sea Surface Salinity Simulation and Projection Surrounding the Asian Waters in the CMIP6 Models

Sea surface salinity (SSS) is a crucial indicator that is used to monitor the hydrological cycle in the ocean system. In this study, we evaluated the simulation skill of the Coupled Model Intercomparison Project Phase 6 (CMIP6) models in reproducing the SSS in the Asian Marginal Seas (AMSs). The results show that the AMSs’ SSS simulated by most CMIP6 models is generally in good agreement with the observations in terms of spatial patterns and seasonal variability. However, these models tend to overestimate the SSS in the Eastern Arabian Sea and the Bay of Bengal by up to 1.3 psu, while they underestimate the SSS in the Bohai Sea, the Yellow Sea, the Southern South China Sea, and the Indonesian Seas, with the bias exceeding −1.5 psu. Additionally, the seasonal variations in the Sea of Okhotsk, the Bay of Bengal, and the Arabian Sea exhibit large biases with phase shift or reversal in some CMIP6 models. Notably, the observed magnitudes in the AMSs are significantly higher than the global average of 0.2 psu, ranging from 0.22 to 1.19 psu. Furthermore, we calculated the projected trends in sea surface salinity under different future scenarios by using the CMIP6 models. The results reveal relatively larger SSS freshening trends in the second half of the 21st century compared to the first half. Specifically, the freshening trends for the Shared Socio-Economic Pathway (SSP) of low- (global radiative forcing of 2.6 W/m2 by the year 2100), medium- (global radiative forcing of 4.5 W/m2 by 2100), and high-end (8.5 W/m2 by 2100) pathways are 0.05–0.21, 0.12–0.39, and 0.28–0.78 psu/century, respectively. The most rapid freshening trends of SSS are observed in the East China Seas and the Indonesian Seas, which are over two times greater than the global mean. On the other hand, the SSS freshening trends in the Arabian Sea are slightly lower than the global mean SSS freshening trend.

Experimental investigation and thermodynamic optimization of the Co–Ta–Zr system

This work is focused on a deeper understanding of the solidification microstructure of the as-cast alloys, as well as the phase constituents and phase fractions of annealed samples in the Co–Ta–Zr system. Nine primary solidification regions were experimentally determined in the liquidus surface projection, and three primary solidification regions were deduced based on binary phase diagrams. Six three-phase equilibria were observed in the isothermal sections at 1373 and 1273 K. The maximum solubilities of Zr in μ and CoTa2 were determined to be ∼ 6.1 and ∼ 6.7 at% at 1373 K, and ∼ 3.9 and ∼ 5.9 at% at 1273 K, respectively. The maximum solubilities of Ta in Co23Zr6 and CoZr were determined to be ∼ 3.3 and ∼ 14.1 at% at 1373 K, and in Co23Zr6, CoZr and CoZr2 were determined to be ∼ 2.6, ∼ 13.5 and ∼ 11.9 at% at 1273 K, respectively. The Co–Ta–Zr system was optimized by CALculation of PHAse Diagram (CALPHAD) method based on the experimental data. Four solution phases, liquid, bcc, fcc, and hcp, were described as substitutional solution. The thermodynamic models of intermetallic phases Co11Zr2, Co23Zr6, CoZr2, Co3Ta, CoTa2, λ1, λ2 and λ3 were treated as (Co)11(Ta,Zr)2, (Co)23(Ta,Zr)6, (Co,Zr)(Ta,Zr)2, Co3(Co,Ta), (Co,Ta,Zr)(Co,Ta,Zr)2, (Co,Ta)2(Co,Ta), (Co,Ta,Zr)2(Co,Ta,Zr) and (Co,Ta)2(Co,Ta) using a two-sublattice model, respectively. CoZr3 was described as (Co,Zr)(Co,Zr)Zr2 by a three-sublattice model. μ phase was modeled as (Co,Ta,Zr)1(Ta,Zr)4(Co,Ta,Zr)2(Co,Ta,Zr)6 using a four-sublattice model. And CoZr with a B2 structure was described as an ordered phase of bcc_A2, and the model was treated as (Co,Ta,Zr,Va)0.5(Co,Ta,Zr,Va)0.5(Va)3. A set of self-consistent thermodynamic parameters of the Co–Ta–Zr system was obtained using CALPHAD method. The calculated solidification paths and phase fractions can provide theoretical guidance for material design and thermal processing.

Microneurosurgical Anatomic Study of the Horizontal Fissure of the Cerebellum.

The horizontal fissure of the cerebellum, which is the largest and most prominent fissure, has received less interest from anatomists and neurosurgeons. Hence, the current study aims to provide comprehensive detail about the horizontal fissure and its anatomic and surgical relationship with deeper structures such as the dentate nucleus and middle cerebellar peduncle for the benefit of the neurosurgeon. Ten whole formalin-fixed human cadaveric cerebellar hemispheres were obtained from human cadavers donated to the institution. Different parameters of the horizontal fissure were studied, such as length, depth (medial end, lateral end, and middle), sulcal and gyral variations (superficial and deep), and its close relationship, especially at depth, with the dentate nucleus and middle cerebellar peduncle. The total length of the horizontal fissure on the right and the left side was 64.3 ± 7.9 mm (range, 53-77 mm) and 65.6 ± 8.01 mm (range, 53-79 mm), respectively. The medial third of the horizontal fissure, with the fewest vessels, was the most suitable place to puncture or start the dissection of the horizontal fissure. The surface projection of the center of the posterior border of the dentate nucleus lies within 20-21 mm on either side of the posterior midline along the horizontal fissure and is only approximately 4 mm deep from the horizontal fissure. The anatomic measurements and relationships provided in this description of the horizontal fissure will serve as a tool for surgery selection and planning, as well as an aid to improve microneurosurgical techniques, with the final goal being better patient outcomes.

A dual-transformation with contrastive learning framework for lymph node metastasis prediction in pancreatic cancer.

Pancreatic cancer is a malignant tumor, and its high recurrence rate after surgery is related to the lymph node metastasis status. In clinical practice, a preoperative imaging prediction method is necessary for prognosis assessment and treatment decision; however, there are two major challenges: insufficient data and difficulty in discriminative feature extraction. This paper proposed a deep learning model to predict lymph node metastasis in pancreatic cancer using multiphase CT, where a dual-transformation with contrastive learning framework is developed to overcome the challenges in fine-grained prediction with small sample sizes. Specifically, we designed a novel dynamic surface projection method to transform 3D data into 2D images for effectively using the 3D information, preserving the spatial correlation of the original texture information and reducing computational resources. Then, this dynamic surface projection was combined with the spiral transformation to establish a dual-transformation method for enhancing the diversity and complementarity of the dataset. A dual-transformation-based data augmentation method was also developed to produce numerous 2D-transformed images to alleviate the effect of insufficient samples. Finally, the dual-transformation-guided contrastive learning scheme based on intra-space-transformation consistency and inter-class specificity was designed to mine additional supervised information, thereby extracting more discriminative features. Extensive experiments have shown the promising performance of the proposed model for predicting lymph node metastasis in pancreatic cancer. Our dual-transformation with contrastive learning scheme was further confirmed on an external public dataset, representing a potential paradigm for the fine-grained classification of oncological images with small sample sizes. The code will be released at https://github.com/SJTUBME-QianLab/Dual-transformation.

Treating Osteoporotic Spinal Fractures in Elderly Patients via a Modified Clinical Bone Cement Injection Technique.

The minimally invasive injection of bone cement (MIIBC) is an effective way to treat senile osteoporotic spinal fractures (OSF) in clinical practice. However, the intraspinal dura and nerves may be damaged when the puncture needle passes through the pedicle. Therefore, in this protocol, the puncture site was optimized during the surgery, selecting the same 1-2 cm away from the surface projection of the diseased vertebra. The needle was punctured along the lateral cortex of the pedicle from the junction of the pedicle and the vertebral body into the vertebral body. Meanwhile, bone cement was used as a filling material, and the MIIBC was performed by a percutaneous puncture at the external edge of the pedicle under C-arm fluoroscopy. This modified puncture site is far away from the spinal canal as possible, thereby reducing the risk of the puncture needles penetrating the spinal canal and damaging the nerves and dura mater. In conclusion, a modified MIIBC by percutaneous lateral pedicle puncture can effectively relieve pain in elderly patients with OSF.

Mid-frequency acoustic localization of breaking waves

During an experiment in deep water off the coast of Southern California, winds between 20 and 25 knots resulted in large breaking waves. A mid-frequency planar hydrophone array recorded underwater ambient noise while an airplane equipped with a high-resolution video camera recorded images of the sea surface above the array. Beams of ambient noise between 5 and 6kHz were projected onto the sea surface and aligned in space and time with the aerial images. The array’s resolution of the surface is coarse (20 by 50 m) due to its modest 1 meter horizontal aperture and relatively deep 130meter deployment depth. Nonetheless, concentrated regions of high intensity in the acoustic surface projection match visible breaking events in the aerial images. [Work supported by the Office of Naval Research.]

Non-planar multinozzle additive manufacturing of thermoset composite microscaffold networks

Material extrusion-based non-planar additive manufacturing (AM) using 6-axis industrial robot arms shows great promise for three-dimensional (3D) printing of non-planar parts, despite its typical use of a single large coarse nozzle and high printing time. Here, a non-planar multinozzle AM method capable of achieving high resolution large-scale 3D printing with short printing time using 6-axis robots is reported. A custom Multinozzle Toolpath Generator (MTG), based on non-planar parameterized surface projection, is used to compute the orientation of a multinozzle extrusion array along the curvature of a 3D scanned substrate. The method is demonstrated by the fast 3D printing of large periodic structures (up to an area of ∼5.2 × 104 mm2 within 20 min) consisting of interconnected epoxy composite microscaffolds on a single curvature sinusoidal surface and a double curvature surface of an actual aircraft casing, with an error of 15 μm. The method could be used for AM in various fields such as tissue engineering, microfluidic channels, and porous acoustic coatings of aircraft components.

Cerebral white matter lesions and regional blood flow are associated with reduced cognitive function in early-stage cognitive impairment.

Differences in the extent of cerebral white matter lesions (WML) and regional cerebral blood flow (rCBF) in early-stage cognitive impairment (ESCI) contribute to the prognosis of cognitive decline; however, it is unclear precisely how WML and rCBF affect cognitive decline in ESCI. We examined the association between WML, rCBF, and cognitive impairment in the ESCI, using path analysis to clarify how these variables affect each other. Eighty-three patients who consulted our memory clinic regarding memory loss were included in this study based on the Clinical Dementia Rating. Participants underwent the Mini-Mental State Examination (MMSE), brain magnetic resonance imaging (MRI) for voxel-based morphometry analysis, and brain perfusion single-photon emission computed tomography (SPECT) for rCBF evaluation in cortical regions, using 3D stereotactic surface projection (3D-SSP) analysis. Path analysis was performed on the MRI voxel-based morphometry and SPECT 3D-SSP data, showing a significant correlation between both and MMSE scores. In the most suitable model (GFI = 0.957), correlations were observed between lateral ventricular (LV-V) and periventricular WML (PvWML-V) volumes [standardized coefficient (SC) = 0.326, p = 0.005], LV-V and rCBF of the anterior cingulate gyrus (ACG-rCBF; SC = 0.395, p < 0.0001), and ACG-rCBF and PvWML-V (SC = 0.231, p = 0.041). Furthermore, a direct relationship between PvWML-V and MMSE scores was identified (SC = -0.238, p = 0.026). Significant interrelationships were observed among the LV-V, PvWML-V, and ACG-rCBF that directly affected the MMSE score in the ESCI. The mechanisms behind these interactions and the impact of PvWML-V on cognitive function require further investigation.

Finite-Source Model of the 8 July 2021 M 6.0 Antelope Valley, California, Earthquake

Abstract We present a finite-source coseismic slip model of the 2021 Mw 6.0 Antelope Valley earthquake based on the joint inversion of regional seismic waveforms, Interferometric Synthetic Aperture Radar (InSAR), and Global Navigation Satellite Systems data. The results show that the mainshock rupture was dominated by normal slip along a nearly north–south-trending fault dipping to the east. The rupture lasted for ∼10 s, with primarily unilateral propagation toward the south. Most coseismic slip is found to be within a depth range between 6 and 10 km, with apparently no slip reaching the surface. Surface projection of the modeled fault plane matches well with the southern extension of the previously mapped Slinkard Valley fault (SVF). Aftershocks one year after the mainshock are mostly distributed within a relatively narrow band of 2–3 km thickness around the up-dip portion of the inferred coseismic rupture plane. There is little aftershock activity below 10 km, suggesting a relatively shallow brittle-to-ductile transition in this area. Aftershocks are also clustered at shallow depth beneath several branches of the Antelope Valley faults to the east of the mainshock rupture, including the Mw 4.4 event on 27 August 2021, which produced clear coseismic surface deformation observed by InSAR. Most aftershocks, immediately up-dip of the coseismic rupture and to the east beneath the Antelope Valley faults, are in areas of substantial coseismic Coulomb stress increase, particularly when assuming that all faults in this area dip to the east. This suggests that like the SVF that hosted the mainshock, the Antelope Valley faults in this area also dip to the east. There is little to no postseismic deformation seen from InSAR observations ∼2 months after the mainshock. The lack of clear coseismic and postseismic slip on the shallow portion of the fault suggests the potential for future shallow seismic activity.

Experimental investigation and thermodynamic description of the Fe–Hf–Nb system

According to solidification microstructure of as-cast alloys and phase constituents of annealed samples, the liquidus surface projection and phase relationships at 1373 and 1273 K in the Fe–Hf–Nb system were constructed. A ternary phase τ with AlCuHf-structure was found, and the composition ranges of Nb in τ at 1373 and 1273 K were ∼ 20.5–30.8 at.% and ∼ 20.8–30.2 at.%, respectively. Moreover, the maximum solubilities of Nb in FeHf2 was determined to be ∼ 16.9 at.% and ∼ 16.0 at.% at 1373 and 1273 K, and the maximum solubilities of Hf in μ was measured to be ∼ 4.6 at% and ∼ 3.3 at.% at 1373 and 1273 K. Fe2Hf and Fe2Nb with the same C14 structure formed a homogeneous solid solution from Fe2Hf to Fe2Nb at 1373 and 1273 K. Seven primary solidification regions in the liquidus surface projection and two three-phase regions and seven two-phase regions in the isothermal sections at 1373 and 1273 K were experimentally determined. On the basis of experimental data, the thermodynamic parameters of individual phases in the Fe–Hf–Nb system were optimized by CALculation of PHAse Diagram (CALPHAD) method. Four solution phases (liquid, bcc, fcc, and hcp) were described as the substitutional solution. The intermetallic phases FeHf2, λ1, λ2, λ3 and τ were modeled as (Fe)1(Hf,Nb)2, (Fe,Hf,Nb)2(Fe,Hf,Nb)1, (Fe)2(Hf)1, (Fe)2(Hf,Nb)1, and (Fe,Hf,Nb)1(Fe,Hf,Nb)1 by a two-sublattice model, respectively. μ was described as (Fe,Hf,Nb)1(Hf,Nb)4(Fe,Hf,Nb)2(Fe,Hf,Nb)6 by a four-sublattice model. A set of self-consistent thermodynamic parameters of the Fe–Hf–Nb system was obtained.

A novel feature fusion model based on non-subsampled shear-wave transform for retinal blood vessel segmentation

Background: Fundus image is a projection of the inner surface of the eye, which can be used to analyze and judge the distribution of blood vessels on the retina due to its different shape, bifurcation and elongation. Vascular trees are the most stable features in medical images and can be used for biometrics. Ophthalmologists can effectively screen and determine the ophthalmic conditions of diabetic retinopathy, glaucoma and microaneurysms by the morphology of blood vessels presented in the fundus images. Traditional unsupervised learning methods include matched filtering method, morphological processing method, deformation model method, etc. However, due to the great difference in the feature complexity of different fundus image morphology, the traditional methods are relatively simple in coding, poor in the extraction degree of vascular features, poor in segmentation effect, and unable to meet the needs of practical clinical assistance. Methods: In this paper, we propose a new feature fusion model based on non-subsampled shearwave transform for retinal blood vessel segmentation. The contrast between blood vessels and background is enhanced by pre-processing. The vascular contour features and detailed features are extracted under the multi-scale framework, and then the image is postprocessed. The fundus images are decomposed into low frequency sub-band and high frequency sub-band by non-subsampled shear-wave transform. The two feature images are fused by regional definition weighting and guided filtering respectively, and the vascular detection image is obtained by calculating the maximum value of the corresponding pixels at each scale. Finally, the Otsu method is used for segmentation. Results: The experimental results on DRIVE data set show that the proposed method can accurately segment the vascular contour while retaining a large number of small vascular branches with high accuracy. Conclusion: The proposed method has a high accuracy and can perform vascular segmentation well on the premise of ensuring sensitivity.

PHASE EQUILIBRA IN THE Ag2Se–Ag8GeSe6–Ag8SiSe6 SYSTEM AND CHARACTERIZATION Of the Ag8Si1-xGexSe6 SOLID SOLUTIONS

Phase equilibria in the Ag2Se–Ag8SiSe6–Ag8GeSe6 system were studied by differential thermal analysis and X-ray diffraction thechnique. Based on the experimental results and literature data, the projection of the liquidus surface of the Ag2Se–Ag8SiSe6–Ag8GeSe6 system, the isothermal section at 300 K and some polythermal sections of the phase diagram were constructed. It was determined that continuous series of solid solution are formed based on high-temperature cubic modification and limited solid solution areas are formed based on low-temperature modification of initial compounds on the Ag8SiSe6–Ag8GeSe6 side of concentration triangle. The formation of solid solutions leads to a sharp decreasing of polymorphic transition temperatures of ternary compounds and stabilization of high-temperature phases at room temperature. The liquidus surface of the Ag2Se–Ag8SiSe6–Ag8GeSe6 system consists of 2 areas reflecting the initial crystallization of α'-phase based on HT-Ag2Se and HT-Ag8Si1-xGexSe6 solid solutions. The obtained new phases are of interest as environmentally safe materials with thermoelectric properties and mixed ion-electron conductivity.