type-II Defects Research Articles

Enhanced Ionic Power Generation via Light-Driven Active Ion Transport Across 2D Semiconductor Heterostructures.

2D semiconductor heterostructures exhibit broad application prospects. However, regular nanochannels of heterostructures rarely caught the researcher's attention. Herein, a metal-organic framework (i.e., Cu3(HHTP)2) and transition metal dichalcogenides (i.e., MoS2)-based multilayer van der Waals heterostructure (i.e., Cu3(HHTP)2/MoS2) realized band alignment-dominated light-driven ion transport and further light-enhanced ionic energy generation. High-density channels of the heterostructure provide high-speed pathways for ion transmembrane transport. Upon light illumination, a net ionic flow occurs at a symmetric concentration, suggesting a directional cationic transport from Cu3(HHTP)2 to MoS2. This is because Cu3(HHTP)2/MoS2 heterostructures containing type-II band alignment can generate photovoltaic motive force through light-induced efficient charge separation to drive ion transport. After introducing into the ionic power generation system, the maximum power density under illumination can achieve notable improvement under different concentration differences. In addition to the photovoltaic motive force, type-II band alignment and material defect capture-induced surface charge increase also raise ion selectivity and flux, greatly facilitating ionic energy generation. This work demonstrates that 2D semiconductor heterostructures with rational band alignment can not only be a potential platform for optimizing light-enhanced ionic energy harvesting but also provide a new thought for biomimetic iontronic devices.

FS-RSDD: Few-Shot Rail Surface Defect Detection with Prototype Learning.

As an important component of the railway system, the surface damage that occurs on the rails due to daily operations can pose significant safety hazards. This paper proposes a simple yet effective rail surface defect detection model, FS-RSDD, for rail surface condition monitoring, which also aims to address the issue of insufficient defect samples faced by previous detection models. The model utilizes a pre-trained model to extract deep features of both normal rail samples and defect samples. Subsequently, an unsupervised learning method is employed to learn feature distributions and obtain a feature prototype memory bank. Using prototype learning techniques, FS-RSDD estimates the probability of a test sample belonging to a defect at each pixel based on the prototype memory bank. This approach overcomes the limitations of deep learning algorithms based on supervised learning techniques, which often suffer from insufficient training samples and low credibility in validation. FS-RSDD achieves high accuracy in defect detection and localization with only a small number of defect samples used for training. Surpassing benchmarked few-shot industrial defect detection algorithms, FS-RSDD achieves an ROC of 95.2% and 99.1% on RSDDS Type-I and Type-II rail defect data, respectively, and is on par with state-of-the-art unsupervised anomaly detection algorithms.

Rail surface defect inspection via a self-reference template and similarity evaluation

Although railway transportation has rapidly evolved in recent times, the existing manual maintenance of rail infrastructure presents several challenges, such as labor intensity and tediousness. Computer vision, as one of the automatic inspection methods, shows promising prospects for railway detection tasks. In this study, we proposed a novel rail surface defect detection method based on a self-reference template and similarity evaluation. Firstly, a self-reference template was generated by extracting the domain information together with the longitudinal direction of the rail image. We further defined an image structural similarity index, and subsequently compared all the transversal rows with the background template. A coarse-to-fine segmentation method was further proposed to locate the defect. In the first step of the segmentation procedure, rows with large differences were selected using the Otsu algorithm adaptively. The exact position of the defect was then determined by utilizing both gradient magnitude and grayscale information. Our method was evaluated on a public rail surface defects dataset, which included two types of data. The experiment results showed that our method detected type-I and type-II defects with 89.04% and 89.61% recall, and 98.46% and 97.87% precision, respectively. This shows that our method achieved higher accuracy than the established detection algorithms.

Revision arthroplasty with rotating hinge systems for total knee arthroplasty instability.

Restoring stability after total knee arthroplasty (TKA) and improving joint function using acemented rotating hinge system. Ligament instability and/or osseous defects (including Anderson Orthopaedic Research Institute [AORI] classification typeII defects) after primary TKA or TKA revision surgery. Distal femoral or proximal tibial bowing requiring implant systems that provide femoral or tibial offset stems. Persistent periprosthetic infection. Poor therapeutic compliance. AORI typeIII defects. Medial arthrotomy. Femoral and tibial component removal with small saw blades and chisels. Intramedullary alignment for the tibial and femoral cuts. Debridement and removal of membranes and cement remnants. Reconstruction of joint line and correct TKA alignment. Trial reduction. Cement fixation. Unrestricted range of motion, partial weight bearing for 4weeks. Between 2012 and 2013, 18patients suffering from ligament insufficiency after TKA were revised using the described system and included in aprospective study protocol. The mean follow-up was 37months (range 30-46months). There was asignificant improvement of the Oxford Knee Score (OKS) from 19 (range 7-29) preoperatively to 29 (range 10-45) postoperatively (p = 0.004). The Knee Society Score (KSS) knee assessment subscore improved from 35 (range 9-70) to 67 (range 35-97) (p = 0.002) and the pain score from 7 (range 0-50) to 24 (range 0-50) (p = 0.008).

A critical analysis of the X-ray diffraction intensities in concentrated multicomponent alloys

AbstractThe decrease in the X-ray diffraction Bragg peak intensity from concentrated multicomponent alloys (CMA), has been modeled in literature akin to the effect of temperature. In the current work, experiments and computations are used to comprehend the effect of atomic disorder in CMA on the Bragg peaks of powder diffraction patterns. Ni–Co–Fe–Cr–Mn and Cu–Ni–Co–Fe–V have been used as model systems for the study. It is proved that the intensity decrease is not insignificant, but is not anomalous either. A recipe is evolved to compare the Bragg peak intensities across the alloys of a CMA. It is demonstrated that it is incorrect to model the effect of an increase in atomic disorder in a CMA, as a temperature effect. A ‘good measure’ of lattice distortion is identified and further it is established that full width half maximum is a good measure of the bond length distortion. It is demonstrated that the true strain due to bond length distortion is of significantly lower magnitude than that given by a priori measures of lattice strain. In the scheme of categorization of defects in crystals, it is argued that CMA is a separate class (as distinct from type-I and type-II defects); which should be construed as a defected solid, rather than a defect in a solid.

Unexpected Fe‐enriched compounds observed in Mg–Ce alloy: An atomic‐scale STEM investigation

This paper investigates into the unexpected nanosize Fe-enriched particles with defects incorporated, using EDS under STEM mode and atomic-resolution HAADF. The particle that locates between eutectic Mg12 Ce phase and α-Mg phase is identified as CeFe2 Si2 compound. Two types of defects are incorporated: Type-I defect is Ce-Si in a simple cubic lattice; Type-II defect is Ce in a FCC lattice. The interface between the defect-free CeFe2 Si2 and the defects is fully coherent. In addition, another two Ce/Fe/Si-enriched particles are observed, proving that the enrichment of Ce, Fe, and Si is not an accidental phenomenon. The observed formation of Ce/Fe/Si-enriched particles provides a possible explanation for the improvement in corrosion resistance and the purification effect induced by addition of rare earth elements into alloys. In addition, the present study demonstrates an advanced application of Cs-corrected HAADF by successfully directly imaging the dislocation and complex defects incorporated in the compound and by achieving a one-angstrom resolution. SCANNING 38:783-791, 2016. © 2016 Wiley Periodicals, Inc.

Fusing defect for the N = 2 super sinh-Gordon model

In this paper we derive the type-II integrable defect for the N =2 supersymmetric sinh-Gordon (sshG) model by using the fusing procedure. In particular, we show explicitly the conservation of the modified energy, momentum and supercharges.

Type-II super-Bäcklund transformation and integrable defects for the N = 1 super sinh-Gordon model

A new super-Bäcklund transformation for the N = 1 supersymmetric sinhGordon equation is constructed. Based on this construction we propose a type-II integrable defect for the supersymmetric sinh-Gordon model consistent with this new transformation through the Lagrangian formalism. Explicit expressions for the modified conserved energy, momentum and supercharges are also computed. In addition, we show for the model that the type-II defect can also been regarded as a pair of fused defects of a previously introduced type. The explicit derivation of the associated defect matrices is also presented as a necessary condition for the integrability of the model.

Type-II defects in the super-Liouville theory

The introduction of type-II defects is discussed under the Lagrangian formalism and Lax representation for the N = 1 super-Liouville model. We derive a new kind of super-Bäcklund transformation for the model and show explicitly the conservation of the modified energy and momentum, as well as supercharge.

A Visual Detection System for Rail Surface Defects

Discrete surface defects are the most common anomalies of rails and they should be carefully inspected. However, it is a challenge to detect such defects in a vision system because of illumination inequality and the variation of reflection property of rail surfaces. This paper presents an intelligent vision detection system (VDS) for discrete surface defects and focuses on two key issues of VDS: image enhancement and automatic thresholding. We propose the local Michelson-like contrast (MLC) measure to enhance rail images. MLC-based method is nonlinear and illumination independent; therefore, it notably improves the distinction between defects and background. In addition, we put forward the new automatic thresholding method-proportion emphasized maximum entropy (PEME) thresholding algorithm. PEME selects a threshold that maximizes the object entropy and meanwhile keeps the defect proportion in a low level. Our experimental results demonstrate that VDS detects the Type-II defects with a recall of 91.61% and Type-I defects with a recall of 88.53%, and the proposed MLC-based image enhancement method and PEME thresholding algorithm outperform the related well-established approaches.

A Real-Time Visual Inspection System for Discrete Surface Defects of Rail Heads

Discrete surface defects impact the riding quality and safety of a railway system. However, it is a challenge to inspect such defects in a vision system because of illumination inequality and the variation of reflection property of rail surfaces. This paper puts forward a real-time visual inspection system (VIS) for discrete surface defects. VIS first acquires a rail image by the image acquisition system, and then, it cuts the subimage of rail track by the track extraction algorithm. Subsequently, VIS enhances the contrast of the rail image using the local normalization (LN) method, which is nonlinear and illumination independent. At last, VIS detects defects using the defect localization based on projection profile (DLBP), which is robust to noise and very fast. Our experimental results demonstrate that VIS detects the Type-II defects with a recall of 93.10% and Type-I defects with a recall of 80.41%, and the proposed LN method and DLBP algorithm are better than the related well-established approaches. Furthermore, VIS is very fast with a linear computational time complexity, and it can be in real time to run on a 216-km/h test train under our experimental setup.

Inverse scattering approach for massive Thirring models with integrable type-II defects

We discuss the integrability of the bosonic and Grassmannian massive Thirring models in the presence of defects through the inverse scattering approach. We present a general method to compute the generating functions of modified conserved quantities for any integrable field equation associated with the m × m spectral linear problem. We apply the method to derive in particular the defect contributions for the number of occupation, energy and momentum of the massive Thirring models.

COMPARISON OF A HYDROXYAPATITE-COATED SLEEVE AND A POROUS-COATED SLEEVE WITH A MODULAR REVISION HIP STEM

Bone ingrowth into a cementless prosthesis can be achieved by both porous and hydroxyapatite coatings. The purpose of this study was to compare the performance of a hydroxyapatite-coated proximal sleeve and a porous bead-coated sleeve in patients managed with a modular revision hip system. Between August 1992 and December 1996, fifty-three consecutive femoral revisions performed with an S-ROM stem in fifty-two patients were prospectively randomized at the time of surgery to either a hydroxyapatite-coated or a porous-coated sleeve. All patients were evaluated clinically and radiographically at three months, six months, and yearly for a minimum of two years (average, four years; range, two to 7.5 years). Femoral defects were classified according to the criteria of Paprosky et al. Six patients died and four patients were lost to follow-up, leaving forty-two patients (forty-three hips) as the final study group. For the entire group, two femoral stems, one of which had been implanted in a hip with a Paprosky type-II femoral defect and the other in a hip with a Paprosky type-IIIB femoral defect, required a repeat revision, one for pain and the other for aseptic loosening. Radiographic evidence of bone ingrowth was observed in 96% (twenty-six) of the twenty-seven femora with type-I or II defects and in 81% (thirteen) of the sixteen femora with type-III defects. Femoral component survival, with use of revision as the end point, was 95% at four years for the entire group. The Harris hip scores were not significantly different when stratified by implant type, but were significantly different when stratified by bone loss (p < 0.05). In the femora with type-I or II defects, no difference was detected between those treated with a hydroxyapatite-coated implant and those that received a porous-coated implant with respect to bone ingrowth. However, in femora with type-III defects, the likelihood of the development of bone ingrowth was 2.6 (95% confidence interval, 1.3 to 5.17) times greater in hips that received a hydroxyapatite-coated implant (all eight developed ingrowth) than in hips that had a porous-coated implant (five of eight developed ingrowth) (p = 0.05). Bone fixation was achieved more often with hydroxyapatite-coated sleeves in femora with Paprosky type-III defects, but no significant difference was noted in outcomes between the two implant types when used in bone with type-I or type-II femoral defects. Overall, the S-ROM modular hip stem performed better in femora with type-I or II bone defects than in femora with type-III defects. Prognostic study, Level II-1 (retrospective study). See Instructions to Authors for a complete description of levels of evidence.

Connection structures between type-I and type-II defects in neutron irradiated beta-Si3N4.

High-resolution electron microscopy (HREM) observation clarified that various types of interstitial dislocations were induced into beta-Si3N4 by high-dose neutron irradiation, and two of them have been analysed and reported in our previous papers. These two defective structures are called type-I and type-II. They are interstitial dislocation loops introduced into [100] and [110] planes, respectively. In this study, it was found that some of these dislocation loops connected with each other. The connections of type-I-L2-type-II-B and type-I-R2-type-II-A dislocations were observed by HREM. Tetrahedral arrangements of the connected parts are proposed, based on the simplified crystal structure model of beta-Si3N4. In addition, a new type of defect, type-III, was found. Type-III is an interstitial dislocation loop introduced into [100] planes. It was also found that type-I-A and type-III dislocations connected with each other.

CLASSIFICATION AND AN ALGORITHMIC APPROACH TO THE RECONSTRUCTION OF FEMORAL DEFICIENCY IN REVISION TOTAL HIP ARTHROPLASTY

As the number of patients who have undergone total hip arthroplasty rises, the number of patients requiring revision surgery for a failed total hip arthroplasty increases as well. It is estimated that 183,000 total hip replacements were performed in the United States in 2000 and that 31,000 (17%) of these were revision procedures1. Femoral reconstruction at the time of revision total hip arthroplasty can be challenging both from a technical perspective and in terms of preoperative planning. With multiple reconstructive options available, it is helpful to have a classification system available to guide the surgeon in selecting the appropriate method of reconstruction. A system for the classification of femoral deficiency that was developed by the senior author (W.G.P.)2 and an algorithmic approach to femoral reconstruction are presented in the current report. Seventy-one consecutive femoral revision arthroplasties that involved reconstruction with an extensively coated, diaphyseal fitting stem were reviewed at a minimum of eight years2. Component stability was classified with use of the system of Engh et al.3. Femoral deficiency was classified as follows. Type I: A femur with a type-I defect has minimal loss of metaphyseal cancellous bone and an intact diaphysis. This type of defect often is seen after the removal of a cementless femoral component without a biological ingrowth surface (Figs. 1-A and 1-B). Fig. 1-A Figs. 1-A and 1-B Type-I femoral deficiency. There is minimal loss of metaphyseal cancellous bone and an intact diaphysis. Fig. 1-B Figs. 1-A and 1-B Type-I femoral deficiency. There is minimal loss of metaphyseal cancellous bone and an intact diaphysis. Type II: A femur with a type-II defect has extensive loss of metaphyseal cancellous bone and an intact diaphysis. This type of defect often is encountered after the removal of a cemented femoral component (Figs. 2-A and 2-B …

Short-lived primary radiation defects in LiF crystals

The spectral and kinetic parameters of electron-pulse-initiated transient absorption and emission of LiF crystals were studied using pulsed spectrometry with a nanosecond time resolution. The measurements were performed in the spectral region of 6 eV, the temperature range of 11–150 K, and within 10−8–10 s after the termination of an electron pulse. It is shown that the electron-pulse irradiation not only gives rise to F, Vk, and H centers in the LiF crystal but also to certain short-lived defects of two types that differ in the spectral positions of the absorptive and radiative transitions, the lifetime, and the temperature dependence of the production efficiency. Defects of type I feature absorptive transitions at 5.5 and 5.1 eV and a radiative transition at 5.8 eV, whereas the absorptive transitions at 5.3 and 4.75 eV and a radiative transition at 4.4 eV are characteristic of type-II defects. It is found that a variation in the ratio between the concentrations of the different types of short-lived centers in the range of 11–150 K does not affect the quantum efficiency of the F centers. It is assumed that the observed centers are self-trapped excitons of various types.

Growth inhibition due to complementation of transforming growth factor-beta receptor type II-defect by human chromosome 3 transfer in human colorectal carcinoma cells.

The transforming growth-beta receptor type II (TGF-beta RII) gene is one of the target genes of the DNA mismatch repair (MMR) defect. The human colorectal carcinoma cell line HCT116 has mutations in the hMLH1 gene and in the microsatellite region of the TGF-beta RII gene, both located on the short arm of chromosome 3. Introduction of the wild-type hMLH1 gene on transferred human chromosome 3 restores many characteristics of MMR-deficiency in HCT116. In this study, we determined whether transfer of chromosome 3 into HCT116 also complements the TGF-beta RII gene defect. We compared in vitro growth characteristics between HCT116 and HCT116 with a transferred chromosome 3 (HCT116 + ch3). The growth was suppressed in HCT116 + ch3 compared with parental HCT116. This suppression was abolished by frequent replacement with fresh medium, suggesting that the autocrine TGF-beta-TGF-beta RII system may be responsible for growth suppression. To explore this possibility, we determined several characteristics essential for the autocrine system. We found that HCT116 + ch3 expresses wild-type as well as mutated TGF-beta RII mRNA. In addition, phosphorylation of TGF-beta RI and growth inhibition were observed in HCT116 + ch3 but not in HCT116 by exposure to exogenous TGF-beta. The amount of TGF-beta1 in HCT116 + ch3 cultures was remarkably less than that in the HCT116, suggesting that TGF-beta produced by HCT116 + ch3 cells may be consumed by the cells. The conditioned medium from HCT116 cultures inhibits HCT116 + ch3 growth. This inhibition was neutralized by the anti-TGF-beta antibody. Taken together, these results strongly suggest that the TGF-beta RII gene defect in HCT116 is complemented by a wild-type gene on the transferred chromosome 3 and that HCT116 + ch3 gained the ability to respond to TGF-beta. Simultaneous complementation of defects of a responsible gene and a major target gene by the chromosome transfer is useful to prove the inactivated phenotypes acquired during colorectal tumorigenesis.

Positron and positronium studies of irradiation-induced defects and microvoids in vitreous metamict silica

To study irradiation-induced defects and structural microvoids in vitreous silica (v-SiO2), positron lifetime, angular correlation of positron annihilation radiation (ACAR), and electron spin resonance (ESR) were measured on v-SiO2 and quartz (c-SiO2) samples irradiated with fast neutrons up to a dose of 4.1×1020 n/cm2. Two kinds of positron-trapping defects have been found to form in v-SiO2 by fast neutron irradiation: type-I and type-II defects. Similar defects also appear in the irradiated c-SiO2, indicating that both the defects are common in v-SiO2 and c-SiO2. The detailed annealing and photo-illumination studies of positron annihilation and ESR for these two defects suggest that the type-I defects are non-bridging oxygen hole centers (NBOHC), while the type-II defects are oxygen molecules which cannot be detected by ESR. Higher dose irradiation than 1.0×1020 n/cm2 causes c-SiO2 to change to metamict (amorphous) phase (m-SiO2). Positronium (Ps) atoms are found to form in microvoids with an average radius of about 0.3 nm in the v-SiO2 and m-SiO2. This suggests that microvoids proved by Ps are structurally intrinsic open spaces and reflect the topologically disordered structure of these phases in the subnanometer scale.

Extended defects of ion-implanted GaAs

Ion-implantation-induced extended defect formation and annealing processes have been studied in GaAs. Mg, Be, Si, Ge, and Sn ions were implanted between 40 and 185 keV over the dose range of 1×1013–1×1015/cm2. Furnace annealing after capping with Si3N4 was performed between 700 and 900 °C for times between 5 min and 10 h. Plan-view and cross-sectional transmission electron microscopy results were correlated with secondary-ion-mass spectroscopy profiles. The results indicate subthreshold (type-I) defect formation occurs at a dose of 1×1014/cm2 for high-energy, light (Mg, Be) ions but not for heavier ions (Si, Ge, Sn) at shallower projected ranges (&amp;lt;500 Å). Si and Ge implants at a dose of 1×1015/cm2 both show extended defect formation upon annealing that is believed to be precipitation related (type-V defects). For Si implants, these dislocation loops are eliminated after 10 h at 900 °C. Upon annealing 1×1015/cm2 Sn implants, unusual precipitate motion both toward the surface and into the crystal was observed. Type-II defects are observed but only in the as-implanted cross section. In addition, a layer of dislocation loops formed at a depth much greater than the type-II defect layer. These defects appear to be a new type of defect possibly related to either the different binary recoil distributions of Ga and As or differences in vacancy and interstitial diffusivities. It is shown that, with modifications to account for the binary nature of the target, the classification scheme developed for extended defects in silicon can be applied to implantation of gallium arsenide.