EPro-PnP: Generalized End-to-End Probabilistic Perspective-N-Points for Monocular Object Pose Estimation.

Locating 3D objects from a single RGB image via Perspective-n-Point (PnP) is a long-standing problem in computer vision. Driven by end-to-end deep learning, recent studies suggest interpreting PnP as a differentiable layer, allowing for partial learning of 2D-3D point correspondences by backpropagating the gradients of pose loss. Yet, learning the entire correspondences from scratch is highly challenging, particularly for ambiguous pose solutions, where the globally optimal pose is theoretically non-differentiable w.r.t. the points. In this paper, we propose the EPro-PnP, a probabilistic PnP layer for general end-to-end pose estimation, which outputs a distribution of pose with differentiable probability density on the SE(3) manifold. The 2D-3D coordinates and corresponding weights are treated as intermediate variables learned by minimizing the KL divergence between the predicted and target pose distribution. The underlying principle generalizes previous approaches, and resembles the attention mechanism. EPro-PnP can enhance existing correspondence networks, closing the gap between PnP-based method and the task-specific leaders on the LineMOD 6DoF pose estimation benchmark. Furthermore, EPro-PnP helps to explore new possibilities of network design, as we demonstrate a novel deformable correspondence network with the state-of-the-art pose accuracy on the nuScenes 3D object detection benchmark. Our code is available at https://github.com/tjiiv-cprg/EPro-PnP-v2.

Maturation of the Female Pharyngeal Airway from Adolescence to Adulthood.

BACKGROUND: The present study aimed to investigate developmental changes in the female pharyngeal airway from adolescence to adulthood, considering variations in the anatomical structures related to the airway dimensions. METHODS: Lateral cephalograms of 214 females were analyzed and categorized into five developmental stages: early adolescence (10-13 years), middle adolescence (14-17 years), late adolescence (18-21 years), early adulthood (22-30 years), and middle adulthood (31-50 years). The focus of the analysis included the point A-Nasion-point B (ANB) angle, tongue pharyngeal airway space (TPS), epiglottis pharyngeal airway space (EPS), soft palate airway space (SPS), and the horizontal and vertical positions of the hyoid bone. RESULTS: The ANB angle exhibited significant variation across groups, being significantly larger in the early-adolescence group (4.22°) compared to the middle-adolescence, late-adolescence, and early-adulthood groups. The TPS and EPS were significantly shorter in the early-adolescence group. Negative correlations were observed between the ANB angle and the lengths of the pharyngeal airway spaces (SPS, TPS, and EPS). The horizontal and vertical positions of the hyoid bone remained stable after middle adolescence. CONCLUSION: The maturation of the ANB angle and pharyngeal airway in females seems nearly completed during middle adolescence (14-17 years). Additionally, a significant and negative correlation was identified between the ANB angle and the lengths of various pharyngeal airway spaces (SPS, TPS, and EPS). The horizontal and vertical positions of the hyoid bone showed stability after middle adolescence.

Strong and ductile titanium-oxygen-iron alloys by additive manufacturing.

Titanium alloys are advanced lightweight materials, indispensable for many critical applications1,2. The mainstay of the titanium industry is the α-ß titanium alloys, which are formulated through alloying additions that stabilize the α and ß phases3-5. Our work focuses on harnessing two of the most powerful stabilizing elements and strengtheners for α-ß titanium alloys, oxygen and iron1-5, which are readily abundant. However, the embrittling effect of oxygen6,7, described colloquially as 'the kryptonite to titanium'8, and the microsegregation of iron9 have hindered their combination for the development of strong and ductile α-ß titanium-oxygen-iron alloys. Here we integrate alloy design with additive manufacturing (AM) process design to demonstrate a series of titanium-oxygen-iron compositions that exhibit outstanding tensile properties. We explain the atomic-scale origins of these properties using various characterization techniques. The abundance of oxygen and iron and the process simplicity for net-shape or near-net-shape manufacturing by AM make these α-ß titanium-oxygen-iron alloys attractive for a diverse range of applications. Furthermore, they offer promise for industrial-scale use of off-grade sponge titanium or sponge titanium-oxygen-iron10,11, an industrial waste product at present. The economic and environmental potential to reduce the carbon footprint of the energy-intensive sponge titanium production12 is substantial.

The Use of Customized Three-Dimensionally Printed Mandible Prostheses with a Pressure-Reducing Device: A Finite Element Analysis in Different Chewing Positions, Biomechanical Testing, and In Vivo Animal Study Using Lanyu Pigs.

Segmental bony defects of the mandible constitute a complete loss of the regional part of the mandible. Although several types of customized three-dimension-printed mandible prostheses (CMPs) have been developed, this technique has yet to be widely used. We used CMP with a pressure-reducing device (PRD) to investigate its clinical applicability. First, we used the finite element analysis (FEA). We designed four models of CMP (P1 to P4), and the result showed that CMP with posterior PRD deployment (P4 group) had the maximum total deformation in the protrusion and right excursion positions, and in clenching and left excursion positions, posterior screws had the minimum von Mises stress. Second, the P4 CMP-PRD was produced using LaserCUSING from titanium alloy (Ti-6Al-4V). The fracture test result revealed that the maximum static pressure that could be withstood was 189 N, and a fatigue test was conducted for 5,000,000 cycles. Third, animal study was conducted on five male 4-month-old Lanyu pigs. Four animals completed the experiment. Two animals had CMP exposure in the oral cavity, but there was no significant inflammation, and one animal had a rear wing fracture. According to a CT scan, the lingual cortex of the mandible crawled along the CMP surface, and a bony front-to-back connection was noted in one animal. A histological examination indicated that CMP was significantly less reactive than control materials (p = 0.0170). Adequate PRD deployment in CMP may solve a challenge associated with CMP, thus promoting its use in clinical practice.

Reliability and benefits of single-energy projection-based metallic artifact reduction (SEMAR) in the different orthopedic hardware for the hip.

OBJECTIVE: To evaluate the performance and reliability of the single-energy metal artifact reduction (SEMAR) algorithm in patients with different orthopedic hardware at the hips. MATERIALS AND METHODS: A total of 153 patients with hip instrumentation who had undergone CT with adaptive iterative dose reduction (AIDR) 3D and SEMAR algorithms between February 2015 and October 2019 were included retrospectively. Patients were divided into 5 groups by the hardware type. Two readers with 21 and 13 years of experience blindly reviewed all image sets and graded the extent of artifacts and imaging quality using 5-point scales. To evaluate reliability, the mean densities and image noises were measured at the urinary bladder, veins, and fat in images with artifacts and the reference images. RESULTS: No significant differences were found in the mean densities of the urinary bladder, veins, and fat between the SEMAR images with artifacts (7.57 ± 9.49, 40.29 ± 23.07, 86.78 ± 38.34) and the reference images (7.77 ± 6.2, 40.27 ± 8.66, 89.10 ± 20.70) (P = .860, .994, .392). Image noises of the urinary bladder in the SEMAR images with artifacts (14.25 ± 4.50) and the SEMAR reference images (9.69 ± 1.29) were significantly higher than those in the AIDR 3D reference images (9.11 ± 1.12) (P < .001; P < .001). All AIDR 3D images were non-diagnostic (overall quality ≤ 3) and less than a quarter of the SEMAR images were non-diagnostic (16.7-23.7%), mainly in patients with prostheses [reader 1: 91.7% (22/24); reader 2: 92.6% (25/27)]. CONCLUSION: The SEMAR algorithm significantly reduces metal artifacts in CT images, more in patients with internal fixations than in patients with prostheses, and provides reliable attenuation of soft tissues.

Skeletal Stability after Mandibular Setback via Sagittal Split Ramus Osteotomy Verse Intraoral Vertical Ramus Osteotomy: A Systematic Review.

PURPOSE: The purpose of present study was to review the literature regarding the postoperative skeletal stability in the treatment of mandibular prognathism after isolated sagittal split ramus osteotomy (SSRO) or intraoral vertical ramus osteotomy (IVRO). MATERIALS AND METHODS: The articles were selected from 1980 to 2020 in the English published databases (PubMed, Web of Science and Cochrane Library). The articles meeting the searching strategy were evaluated based on the eligibility criteria, especially at least 30 patients. RESULTS: Based on the eligibility criteria, 9 articles (5 in SSRO and 4 in IVRO) were examined. The amounts of mandibular setback (B point, Pog, and Me) were ranged from 5.53-9.07 mm in SSRO and 6.7-12.4 mm in IVRO, respectively. In 1-year follow-up, SSRO showed the relapse (anterior displacement: 0.2 to 2.26 mm) By contrast, IVRO revealed the posterior drift (posterior displacement: 0.1 to 1.2 mm). In 2-year follow-up, both of SSRO and IVRO presented the relapse with a range from 0.9 to 1.63 mm and 1 to 1.3 mm respectively. CONCLUSION: In 1-year follow-up, SSRO presented the relapse (anterior displacement) and IVRO posterior drift (posterior displacement). In 2-year follow-up, both of SSRO and IVRO showed the similar relapse distances.

Investigation of the Effectiveness of Surgical Treatment on Maxillary Medication-Related Osteonecrosis of the Jaw: A Literature Review.

AIM: Medication-related osteonecrosis of the jaw (MRONJ) occurs after exposure to medication (antiresorptive or antiangiogenic agents) for bone-related complications. It is more common in the mandible than in the maxilla. The present study investigated maxillary MRONJ in elderly patients through a meta-analysis. METHODS: Keywords, including "MRONJ", "maxilla", and "surgery", were entered into databases, including Embase, PubMed/MEDLINE, Cochrane Library, and ProQuest, which were searched systematically. RESULTS: Investigating 77 studies, we found that 18 (2 case reports and 16 case series) papers conformed to the standards. The results revealed a 2.6:1 female-to-male ratio of disease occurrence. The average age of patients was 70.6 ± 5.5 years, and most patients were in the third stage (43.6%). The average time of medication usage was 50.0 ± 20.1 months. The pooled proportion of clinical efficacy of surgery was 86%. CONCLUSION: To prevent and manage MRONJ, all elderly patients should maintain proper oral hygiene and receive dental examinations regularly. Risk assessment and safety management of MRONJ should be performed by medical teams.

Effect of Microimplant Neck Design with and without Microthread on Pullout Strength and Destruction Volume.

The microthread neck concept has been applied to dental implants. This study investigated the pullout strength and destruction volume of orthodontic microimplants with and without the microthread neck design. Fifteen microimplants (diameter: 1.5 × 10 mm) of three types (Types A and B: without microimplant neck; Type C: with microimplant neck) were tested. The insertion torque (IT), Periotest value (PTV), horizontal pullout strength (HPS), and horizontal destruction volume (HDV) of each type were measured. Kruskal-Wallis H test and Dunn's post-hoc comparison test were performed to compare the measured values of the three types of microimplants. The correlations of the measured values were used to perform the Spearman's correlation coefficient analysis. The ITs of Types B (8.8 Ncm) and C (8.9 Ncm) were significantly higher than those of Type A (5.2 Ncm). Type B yielded the lowest PTV (4.1), and no statistical differences in PTV were observed among the three types. Type A had a significantly lower HPS (158.8 Ncm) than Types B (226.9 Ncm) and C (212.8 Ncm). The three types did not exhibit any significant differences in the HDV. The results of the Spearman's correlation coefficient test revealed that HDV (ρ = 0.710) and IT (ρ = 0.813) were strongly correlated with HPS, whereas for PTV and HPS, it was not. HPS was strongly and significantly correlated with HDV. The orthodontic microimplant with a microimplant neck design did not perform better than that without a microthread in the mechanical strength test.

Changes in Pharyngeal Airway Space and Craniocervical Angle after Anterior Bimaxillary Subapical Osteotomy.

PURPOSE: This study explored the effects of genioplasty (Gep) and anterior subapical osteotomy of the maxilla and mandible (ASOMx+ASOMd) on the pharyngeal airway dimensions of patients with bimaxillary protrusion (BiP). METHOD: Thirty-two patients were divided into 2 groups. Group 1 received ASOMx+ASOMd, and group 2 received ASOMx+ASOMd+Gep. The cephalograms of the patients were collected before surgery and 2 months after surgery. Changes in the landmarks, related cephalometric angles (gonial, SN-GoGn, Y-axis, and SN-C2C4 angles), and 2 pharyngeal airway dimensions (uvulo-pharyngeal airway [UOP] and tongue-pharyngeal airway [TOP]) were analyzed. RESULTS: Before surgery, the parameters (incisor superius, incisor inferius, menton, most superior and anterior point of the hyoid bone, tip of the uvula, inferoanterior point on the second cervical vertebra, and inferoanterior point on the fourth cervical vertebra) and measured angles (SNA, SNB, ANB, gonial, SN-GoGn, Y-axis, and C4C2-SN) of both groups showed no significant differences. Following ASOMx, the patients in groups 1 and 2 exhibited a setback by 7.0 and 6.6 mm, respectively. After ASOMd, groups 1 and 2 exhibited 4.9 and 5.3 mm setbacks, respectively. No significant difference in the amount of setback was observed between groups 1 and 2. The postoperative horizontal and vertical positions of Me in group 2 were significantly forward by 6.1 mm and upward by 1.5 mm, respectively. Regarding pharyngeal airway dimensions, TOP was decreased in group 1 (1.7 mm) and group 2 (1.3 mm). In the postoperative Pearson correlation coefficient test, the horizontal and vertical positions of Me showed no significant correlation with TOP in both groups. Therefore, Gep did not prevent the reduction of TOP in group 2. CONCLUSION: After bimaxillary anterior subapical osteotomy, the TOP of patients with BiP was decreased, and this situation was unavoidable, regardless of whether Gep was performed.

Solution Epitaxy of Halide Perovskite Thin Single Crystals for Stable Transistors.

Halide perovskites hold promise for energy and optoelectronic applications due to their fascinating photophysical properties and facile processing. Among various forms, epitaxial thin single crystals (TSCs) are highly desirable due to their high crystallinity, reduced defects, and easy epitaxial integration with other materials. However, a cost-effective method for obtaining TSCs with perfect epitaxial features remains elusive. Here, we demonstrate a direct epitaxial growth of high-quality all-inorganic perovskite CsPbBr3 TSCs on various substrates through a facile solution process under near-ambient conditions. Structural characterizations reveal a high-quality epitaxy between the obtained perovskite TSCs and substrates, thus leading to efficiently reduced defects. The resultant TSCs display a low trap density (∼1011 cm-3) and a long carrier lifetime (∼10.16 ns). Top-gate/top-contact transistors based on these TSCs exhibit high on/off ratios of over 105, an optimal hole mobility of 3.9 cm2 V-1 s-1, almost hysteresis-free operation, and high stability at room temperature. Such a facile approach for the high-yield production of perovskite epitaxial TSCs will enable a broad range of high-performance electronic applications.

Analysis of Facial Skeletal Morphology: Nasal Bone, Maxilla, and Mandible.

The growth and development of facial bones are closely related to each other. The present study investigated the differences in the nasomaxillary and mandibular morphology among different skeletal patterns. Cephalograms of 240 participants were divided into 3 groups based on the skeletal pattern (Class I, Class II, and Class III). The dimensions of nasomaxilla (nasal bone length, nasal ridge length, nasal depth, palatal length, and maxillary height) and mandible (condylar length, ramus length, body length, symphysis length, and entire mandibular length) were measured. One-way analysis of variance and Pearson's correlation test were used for statistical analysis. No significant differences were observed among the skeletal patterns in terms of nasal bone length, palatal length, maxillary height, or condylar length. Class II had a significantly shorter ramus, mandibular body, and entire mandibular length compared with those of Class I and Class III. Nasal ridge length exhibited a significant moderate correlated with nasal bone length (correlation coefficient: 0.433) and maxillary height (correlation coefficient: 0.535). The entire mandibular length exhibited a significant moderate correlated with ramus length (correlation coefficient: 0.485) and body length (correlation coefficient: 0.536). In conclusion, nasal and maxillary dimensions exhibited no significant difference among the 3 skeletal patterns. Mandibular body and entire mandibular lengths were significantly positively correlations with Class III skeletal patterns.

The investigation of pharyngeal airway space by cephalogram landmarks in primary school children in Taiwan.

BACKGROUND/PURPOSE: Proper breathing is essential to healthy growth and development of children. The present study aimed to investigate changes in the pharyngeal airway space in primary-school children. MATERIALS AND METHODS: Cephalometric radiographs were obtained from 93 primary-school children, who were divided into three age groups (Group I, aged 7-8 years; Group II, aged 9-10 years; and Group III, aged 11-12 years). Landmarks identified on each cephalogram included the tip of the uvula (U), hyoid bone (H), and epiglottis (E). Linear and angular measurements comprised nasopharyngeal airway (NP); PS (shortest distance from the soft palate to the pharyngeal wall); UP (distance from the tip of the uvula to the pharyngeal wall); TS (shortest distance from the posterior tongue to the pharyngeal wall); EP (distance, parallel to the X-axis, from the epiglottis to the pharyngeal wall). Statistical analysis was performed using one-way analysis of variance and Pearson correlation tests. RESULTS: Group III had the highest values for all the variables. The three groups exhibited significant differences for all pharyngeal airway variables, except for EP. The three groups had significantly different vertical U, H, and E. There were positive correlations between age and NP, PS, UP, and TS; however, no significant correlation was observed between age and EP. Age significantly correlated with the vertical U, E, and H. Correlations between age and the horizontal U, E, and H were nonsignificant. CONCLUSION: Among primary-school children from various grades, age significantly correlated with all pharyngeal airway variables, except with EP.

Antilingula as a Surgical Reference Point for Vertical Ramus Osteotomy.

PURPOSE: This study investigated the antilingula and its related landmarks, the mandibular rami, by using cone-beam computed tomography (CBCT). METHODS: CBCT images of 37 patients (74 sides of the mandibular ramus) were collected. The landmarks of antilingula (AntiL), anterior ramus (A), posterior ramus (P), superior ramus (S), and inferior ramus (I) were identified. The distances (A-AntiL, P-AntiL, S-AntiL, and I-AntiL) were statistically evaluated according to gender, side (right and left), and skeletal patterns. RESULTS: The distance from the antilingula to the anterior (A-AntiL) border of the ramus was significantly longer on the right side (14.69 mm) than on the left side (13.97 mm). Male patients had longer AntiL-P, AntiL-I, and S-I distances (18.96, 40.07, and 54.94 mm, respectively) than did female patients (16.66, 35, and 47.54 mm, respectively). Regarding skeletal patterns, the classes can be ordered as follows in terms of the measurements: class III>class II>class I. However, the differences between the classes were nonsignificant. Pearson correlation analysis revealed that gender and S-I distance were strongly correlated (r = 0.667); specifically, male patients had a longer S-I distance. A-AntiL and A-P also exhibited a strong correlation (r = 0.796). CONCLUSION: Antilingula-related distances did not differ between skeletal patterns. Among antilingula-related variables, A-AntiL could serve as a favorable measuring point during operation.

The correlation between surgical reference points: antilingula, lingula, and mandibular foramen.

The purpose of the present study was to investigate and determine the anatomical relationship between the antilingula, lingula, and mandibular foramen using cone-beam computed tomography (CBCT). METHODS: CBCT images of 90 participants (180 mandibular ramus) were collected. The locations of and distances between the antilingula, lingual, and mandibular foramen according to side (right and left) and skeletal patterns were measured and then evaluated by statistical analysis. RESULTS: Only 27 participants (15%) had bilateral distinct antilingula, lingula, and mandibular foramen. The antilingula was located anteriorly (4.28 mm and 3.59 mm) and above (1.99 mm and 8.52 mm) the lingula and mandibular foramen. The lingula was behind (0.69 mm) and above (6.53 mm) the mandibular foramen. Skeletal Class III was anterior and inferior to Class II and Class I in the antilingula, lingula, and mandibular foramen. Considering the correlations of landmarks, we found that the lingula was strongly correlated with the mandibular foramen on the X axis (r = 0.757) and Y-axis (r = 0.878). CONCLUSION: The antilingula is located anteriorly and above the lingula and mandibular foramen. The lingula is behind and above the mandibular foramen. The osteotomy line of orthognathic surgery can only be safely designed through actual measurement of the locations of the antilingula, lingula, and mandibular foramen.

Nanoscale pathways for human tooth decay - Central planar defect, organic-rich precipitate and high-angle grain boundary.

Understanding the pathways and mechanisms of human tooth decay is central to the development of both prophylaxes and treatments, but only limited information is presently available about the initiation of caries at the nanoscale. By combining atom probe tomography and high-resolution electron microscopy, we have found three distinct initial sites for human dental enamel dissolution: a) along the central dark line (CDL) within carbonated apatite nanocrystals, b) at organic-rich precipitates and c) along high-angle grain boundaries. 3D maps of the atoms within hydroxyapatite nanocrystallites in sound and naturally-decayed human dental enamel reveal a higher concentration of Mg and Na in the CDL. The CDL is therefore thought to provide a pathway for the exchange of ions during demineralization and remineralization. Mg and Na enrichment of the CDL also suggests that it is associated with the ribbon-like organic-rich precursor in amelogenesis. Organic-rich precipitates and high-angle grain boundaries were also shown to be more vulnerable to corrosion while low-angle grain boundaries remained intact. This is attributed to the lower crystallinity in these regions.

Clinical significance of buccal branches of the facial nerve and their relationship with the emergence of Stensen's duct: An anatomical study on adult Taiwanese cadavers.

OBJECTIVE: This observational study on adult Taiwanese cadavers focused mainly on the intersection of buccal branches of the facial nerve with Stensen's duct, using the emergence of Stensen's duct as the reference landmark. MATERIALS AND METHODS: Thirty-five cadaveric hemifaces were included in our research. Samples with facial defects due to tumor, trauma, or surgery were all excluded. Buccal branches of the facial nerve were identified according to the Gray's Anatomy 40th edition definition. The distance was measured from the intersection to the emergence of Stensen's duct, running from the anterior border of the parotid gland. RESULTS: In the 35 hemifaces, the number of buccal branch/Stensen's duct intersections ranged from 1 to 5 (average 2.49 ± 1.15). Two-point intersections accounted for 37% (13 hemifaces) of the sample, forming the largest group. Samples of facial nerve buccal branches were divided into four types: Type 1, with two buccal branches, accounted for 37.15% (13/35); Type 2, with three buccal branches, made up 48.59% (17/35) of our samples - the biggest group (Type 2-a was the most frequent pattern among our samples, with two superior buccal branches and one inferior buccal branch, accounting for 34.31% of our samples); Type 3, with four buccal branches, accounted for only 5.7%. Three cases of double Stensen's duct were classified as Type 4, though this is supposed to be a very rare anatomical variation. With Type 2a, the most frequent pattern among our specimens, the distance from the emergence of the Stensen's duct to the emergence point of the first superior buccal branch along the anterior border of the parotid gland was 9.58 ± 5.68 mm. The distance from the emergence point to the emergence of the inferior buccal branch along the anterior border of the parotid gland was 11.03 ± 5.38 mm. The distance (D1) from Stensen's duct to the emergence of the first superiorly located buccal branch of the group Type 2-a was statistically different from the distance (D1) of the other groups (p = 0.02). No direct anastomoses or communicating fibers between upper and lower buccal branches were noted in 11 hemifaces (31%). CONCLUSION: The distribution of buccal branches was described using the emergence of Stensen's duct as a reference landmark. According to our observations, the relationship between the buccal branches and Stensen's duct was much more complicated than described in previous studies. This was the first study to investigate the complete distribution of buccal branches of the facial nerve emerging from the anterior of the parotid gland, and their relative locations and branching numbers.

Quantitative Determination of How Growth Conditions Affect the 3D Composition of InGaAs Nanowires.

Covering a broad optical spectrum, ternary InxGa1-xAs nanowires, grown by bottom-up methods, have been receiving increasing attention due to the tunability of the bandgap via In composition modulation. However, inadequate knowledge about the correlation between growth and properties restricts our ability to take advantage of this phenomenon for optoelectronic applications. Here, three different InGaAs nanowires were grown under different experimental conditions and atom probe tomography was used to quantify their composition, allowing the direct observation of the nanowire composition associated with the different growth conditions.

Non-destructive analysis on nano-textured surface of the vertical LED for light enhancement.

In this work, the nano-textured surface of a GaN-based vertical light emitting diode (VLED) is characterized using a unified framework of non-destructive techniques (NDT) incorporating scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman spectroscopy, Photoluminescence (PL), and X-ray diffraction (XRD) to optimize the light output efficiency. The surface roughness of ∼300 nm is revealed by AFM. Compressive stress-state of 0.667 GPa in the GaN surface is indicated by the E2(high) and A1(LO) phonon peak values at 569 cm-1 and 736 cm-1, respectively, in Raman spectrum and the wavelength at 442 nm rather 450 nm in PL spectrum. Without damaging the LED, surface analysis by NDT helps to advance the understanding of the optimized angular light redistribution subject to the high-roughness surface and the negative impacts of the stress induced at the top GaN layer, which leads to the optical efficiency degradation of the VLED. Furthermore, the impact of texturing on underneath n-GaN and MQWs layers is investigated via SEM-based transmission Kikuchi diffraction (TKD) and aberration-corrected scanning transmission electron microscopy (AC-STEM) and revealed a smooth surface morphology and good crystalline quality, indicating that the etch-induced damage by texture engineering does not impair the active region of the VLED. Accordingly, prospective optimizations are suggested in the context of surface engineering for light enhancement in VLEDs.

Grain size quantification by optical microscopy, electron backscatter diffraction, and magnetic force microscopy.

Quantification of microstructure, especially grain size, in polycrystalline materials is a vital aspect to understand the structure-property relationships in these materials. In this paper, representative characterization techniques for determining the grain size, including optical microscopy (OM), electron backscatter diffraction (EBSD) in the scanning electron microscopy (SEM), and atomic force microscopy/magnetic force microscopy (AFM/MFM), are thoroughly evaluated in comparison, illustrated by rare-earth sintered Nd-Fe-B permanent magnets. Potential applications and additional information achieved by using aforementioned characterization techniques have been discussed and summarized.

3D Atomic-Scale Insights into Anisotropic Core-Shell-Structured InGaAs Nanowires Grown by Metal-Organic Chemical Vapor Deposition.

III-V ternary InGaAs nanowires have great potential for electronic and optoelectronic device applications; however, the 3D structure and chemistry at the atomic-scale inside the nanowires remain unclear, which hinders tailoring the nanowires for specific applications. Here, atom probe tomography is used in conjunction with a first-principles simulation to investigate the 3D structure and chemistry of InGaAs nanowires, and reveals i) the nanowires form a spontaneous core-shell structure with a Ga-enriched core and an In-enriched shell, due to different growth mechanisms in the axial and lateral directions; ii) the shape of the core evolves from hexagon into Reuleaux triangle and grows larger, which results from In outward and Ga inward interdiffusion occurring at the core-shell interface; and iii) the irregular hexagonal shell manifests an anisotropic growth rate on {112}A and {112}B facets. Accordingly, a model in terms of the core-shell shape and chemistry evolution is proposed, which provides fresh insights into the growth of these nanowires.