Multilayer Defects Research Articles

Simultaneous processing of both handheld biomixing and biowriting of kombucha cultured pre-crosslinked nanocellulose bioink for regeneration of irregular and multi-layered tissue defects

The nanocellulosic pellicle derived from the symbiotic culture of bacteria and yeast (Kombucha SCOBY) is an important biomaterial for 3D bioprinting in tissue engineering. However, this nanocellulosic hydrogel has a highly entangled gel network. This needs to be partially modified to improve its processability and extrusion ability for its applications in the 3D bioprinting area. To control its mechanical and biological properties for direct 3D bioprinting applications, uniform reinforcement of nanocellulose-interacting polymers and nanoparticles in such a prefabricated gel network is essential. In this study, the hydrogel network is partially hydrolyzed with organic acid and subsequently transformed into a 3D bioprintable polyelectrolyte complex with chitosan and kaolin nanoparticles without any chemical crosslinker using a handheld 3D bioprinter. This handheld bioprinter ensures homogeneity in both biomixing and bioprinting of chitosan and kaolin within the modified nanocellulose network for multi-layered bioprinted scaffolds through an extensional shear mechanism. The biomixing simulation, mechanical (static, dynamic, and cyclic), 3D bioprinting, and cellular studies confirm the homogeneous biomixing of kaolin nanoparticles and live cells in this nanocellulose-chitosan polyelectrolyte hydrogel. The combination of SCOBY-derived nanocellulose-chitosan bioink with kaolin nanoparticles and a screw-driven handheld extrusion bioprinter demonstrates a promising platform for layer-by-layer regeneration of complex tissues with homogeneous cell/particle distribution with high cell viability.

Characterization of Multi-Layer Rolling Contact Fatigue Defects in Railway Rails Using Sweeping Eddy Current Pulse Thermal-Tomography

Railways play a pivotal role in national economic development, freight transportation, national defense, and regional connectivity. The detection of rolling contact fatigue (RCF) defects in rail tracks is essential for railway safety and maintenance. Due to its efficiency and non-contact capability in detecting surface and near-surface defects, Eddy Current Pulsed Thermography (ECPT) has garnered significant attention from researchers. However, detecting multi-layer RCF defects remains a challenge. This paper introduces a sweeping Eddy Current Pulsed Thermal-Tomography system (ECPTT) to detect multi-layer RCF defects effectively. This system utilizes varying excitation frequencies to heat defects, altering skin depth and facilitating feature extraction to distinguish multi-layer RCF defects. Skewness and thermographic signal reconstruction (TSR) values are employed as features in the experiments. These features are qualitatively analyzed to differentiate the layers and depths of multi-layer RCF defects. Additionally, five different coils were compared and analyzed quantitatively. The results indicate that the ECPTT system can effectively detect and distinguish multi-layer RCF defects, thereby providing more detailed defect information and enhancing railway safety and maintenance efficiency.

Detection of Multi-Layered Bond Delamination Defects Based on Full Waveform Inversion.

This study aimed to address the challenges encountered in traditional bulk wave delamination detection methods characterized by low detection efficiency. Additionally, the limitations of guided wave delamination detection methods were addressed, particularly those utilizing reflected waves, which are susceptible to edge reflections, thus complicating effective defect extraction. Leveraging the full waveform inversion algorithm, an innovative approach was established for detecting delamination defects in multi-layered structures using ultrasonic guided wave arrays. First, finite element modeling was employed to simulate guided wave data acquisition by a circular array within an aluminum-epoxy bilayer structure with embedded delamination defects. Subsequently, the full waveform inversion algorithm was applied to reconstruct both regular and irregular delamination defects. Analysis results indicated the efficacy of the proposed approach in accurately identifying delamination defects of varying shapes. Furthermore, an experimental platform for guided wave delamination defect detection was established, and experiments were conducted on a steel-cement bilayer structure containing an irregular delamination defect. The experimental results validated the exceptional imaging precision of our proposed technique for identifying delamination defects in multi-layered boards. In summary, the proposed method can accurately determine both the positions and sizes of defects with higher detection efficiency than traditional pulse-echo delamination detection methods.

Reconstruction options for infection-related defects : Plastic surgery armamentarium

The occurrence of infections has always been feared in all surgical disciplines. Plastic reconstructive surgery faces the challenge of treating infection-related defects on apatient-specific basis, which requires amultidisciplinary treatment concept. Satisfactory treatment success can only be achieved through radical debridement for infection cleansing, optimization of the perfusion situation paired with targeted anti-infective treatment and, if necessary, with soft tissue reconstruction by plastic surgery. This article presents the current possibilities of plastic and reconstructive surgery with respect to the reconstruction of infection-related defects. Proven and reliable strategies are presented and supplemented by promising experimental approaches. Due to the often multilayered defect situation caused by infections, from the epidermis to cancellous bone, the entire armamentarium of plastic and reconstructive surgery is used for reconstruction. The early involvement of plastic surgery in the treatment of infections and the interdisciplinary and multimodal treatment approach have proven their worth in the treatment of complex infection situations.

Review of the types, formation mechanisms, effects, and elimination methods of binder jetting 3D-printing defects

Additive Manufacturing (AM), commonly referred to as 3D printing, has ushered in a transformative era in the realm of material fabrication. Due to its innovative layer-adhesive methodology, Binder Jetting (BJ) is anticipated to ascend as the method of choice for synthesizing a vast array of materials. Presently, the defects inherent in BJ technique have precipitated considerable detriments to the quality of resultant components. In response, this exhaustive review delineates the foundational principles of the BJ methodology firstly and endeavors to compile a comprehensive inventory of potential defects encountered during printing. Based on formation mechanism, for the first time, the defects associated with BJ are methodically categorized into quintuple classifications, including slicing defect, powder spreading defect, single-layer printing defect, multi-layer accumulation defect and depowdering defect. Particular heed is devoted to the anomalies precipitated by the binder's interaction with the powder bed, which fundamentally sets BJ apart from conventional AM methodologies. An amalgamation of numerical algorithms and physical paradigms is introduced in each corresponding classification to arm researchers with a profound comprehension of the mechanism behind these defects. Moreover, a variety of mitigation strategies for these corresponding defects, encompassing binder selection, procedural parameter refinement, post-processual interventions and the integration of hybridized techniques are further explored and summarized. Finally, it concludes by pinpointing existing lacunae within the domain of BJ research and projects their future directions. This manuscript, by offering a comprehensive review of defects, aspires to serve as a scholarly compendium for the impending scientific and technological advancements in BJ technology.

Phase defect characterization using generative adversarial networks for extreme ultraviolet lithography.

The multilayer defects of mask blanks in extreme ultraviolet (EUV) lithography may cause severe reflectivity deformation and phase shift. The profile information of a multilayer defect is the key factor for mask defect compensation or repair. This paper introduces an artificial neural network framework to reconstruct the profile parameters of multilayer defects in the EUV mask blanks. With the aerial images of the defective mask blanks obtained at different illumination angles and a series of generative adversarial networks, the method enables a way of multilayer defect characterization with high accuracy.

Through-focus EUV multilayer defect compensation considering optical proximity correction.

Extreme ultraviolet (EUV) multilayer defects result in the degradation of through-focus imaging quality. The optical proximity effect is another crucial factor that degrades the imaging quality. Both the impacts of the defects and the optical proximity effects could be mitigated by modifying the original mask patterns. A heuristic-based defect compensation method considering optical proximity correction and through-focus optimization is proposed in this paper. The edge of the mask pattern and the insertion of sub-resolution assist features (SRAFs) are optimized by covariance matrix adaptation evolution strategy (CMA-ES) to compensate for the degradation of the imaging quality with a certain defocus range. New encoding strategies for the edge pixels of the mask pattern and the SRAFs are proposed and utilized in this paper to ensure the manufacturability of the mask and the efficiency of the optimization at the same time. The rigorous database approach based on the scattering matrix is adopted to simulate the mask diffraction spectrum efficiently. Simulations verify that the through-focus imaging quality of both the defective masks with bump defects and pit defects could be obviously improved by the proposed defect compensation method.

Dynamic Structural Changes of Iron Oxide Nanostructures On Cu(111)

Understanding the structural dynamics of supported iron oxide nanostructures (NSs) and their interfaces with metals is essential for the rational design of iron-oxide-based catalysts for a number of major catalytic reactions. In this study, we have constructed well-defined FeO NSs on Cu(111) to study their surface structures and dynamic changes during the redox treatments using the combination of scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). As deposited FeO NSs were found to exhibit various orientations on Cu(111) with the presence of multilayer FeOx, dislocation, and defect lines on the surface plane of FeO. The oxidation of the FeO/Cu(111) surface in O2 was facilitated by the presence of FeO NSs, causing the formation of the stripe phase of Cu2O1+x surrounding FeO. Meanwhile, the oxidation of FeO NSs also led to the formation of FeOx clusters with predominantly Fe3+ species, which were transformed into 3D FeOx nanoparticles (NPs) upon the annealing at 800 K in UHV while no reduction of Fe3+ species was obvious from XPS. Overall, an irreversible structural dynamics was observed at the atomic level for FeO NSs on Cu(111) during the redox treatments, which furthered our understanding of the FeO–Cu interface.

Reconstruction of columella and nasal vestibuli by bilateral nasolabial flaps - A case report.

Introduction and importanceThe nose is a common location for non-melanoma skin cancers. Resection of such cancers can result in large, multilayer defects that are challenging to reconstruct. The surgical approach is determined by multiple factors and the main goal is to obtain a satisfactory functional and aesthetic result. We present a case of reconstruction of the nasal vestibuli and columella by two transnasal nasolabial flaps.Presentation of caseA 66-year-old male underwent resection of a large squamous cell carcinoma in the right nasal vestibulum that extended through the columella into the left vestibulum. The resection resulted in a multilayer defect including the floor and roof of the right vestibulum, the entire columella, part of the septum cartilage and floor of the left vestibulum. The defect was reconstructed in two stages by bilateral nasolabial flaps, that were brought into the nasal cavity through incisions on the side of the nose and were used to line the vestibuli and sutured to each other medially to form the neocolumella. No complications or surgical site infections were observed.Clinical discussionTransnasal nasolabial flaps can be used for larger columellar defects. The length of the flaps in our case provided enough tissue to reconstruct the columella as well as the entire vestibular linings.ConclusionWe describe a successful reconstruction of the nasal vestibuli and columella with two transnasal nasolabial flaps, which provided an acceptable aesthetic and functional result.

Nasal reconstruction with paramedian forehead flaps

The nose has an important function in the esthetic perception of the face. The esthetic coverage of defects on the nose is therefore of particular importance; however, the position is exposed to sunlight and poses aparticular risk for the development of non-melanoma skin cancer (NMSC) and melanomas. After tumor excision, the size of the defect is decisive for defect closure. In addition, multilayer defects in which the cartilage or mucous membranes must be reconstructed by plastic surgery, represent aparticular challenge for the surgeon. There are various options for reconstruction depending on the extent of the defects on the nose. This article gives an overview of the paramedian forehead flap, the indications and implementation.

EUV multilayer defect characterization via cycle-consistent learning

Extreme ultraviolet (EUV) lithography mask defects may cause severe reflectivity deformation and phase shift in advanced nodes, especially like multilayer defects. Geometric parameter characterization is essential for mask defect compensation or repair. In this paper, we propose a machine learning framework to predict the geometric parameters of multilayer defects on EUV mask blanks. With the proposed inception modules and cycle-consistent learning techniques, the framework enables a novel way of defect characterization with high accuracy.

The relationship between hole size and the voltage-driven formation of surface structures in an ITO/liquid crystal polymer/perforated metal electrode system

A device consisting of a multidomain liquid crystal polymer network sandwiched between a continuous electrode and a perforated silver electrode shows strong surface deformations upon application of an electric field between the electrodes. Here, a new method is presented for the preparation of such a device, in which a silver film with circular holes of a well-controlled diameter was made by evaporating silver onto a monolayer of polystyrene spheres. Due to multilayer defects of the polystyrene microparticle lithography template, larger combined holes were present, which provided interesting information about the effect of pore size on the deformation behavior. The results were compared to an electrostatic field distribution, from which the conclusion could be drawn that there is a minimum hole size that allows deformation. This knowledge is important for the development of applications for this kind of device, as the aspect ratio of the deformations is of crucial importance for effects such as switchable wetting and self-cleaning.

Inspection of Stochastic Defects With Broadband Plasma Optical Systems for Extreme Ultraviolet (EUV) Lithography

As extreme ultraviolet (EUV) lithography enters high volume manufacturing (HVM) to enable the sub-7nm scaling roadmap, characterizing and monitoring defects that print at wafer level are of critical importance to yield. This is especially true for defects coming from the EUV mask, due to multi-layer defects or added particles or growth on mask during its use, and for defects coming from the pattern formation process itself, which are known as stochastic printing defects or simply stochastic defects. In this paper we focus on developing inspection solutions for stochastic defects, which essentially are random local variations that occur between structures that should, in principle, print identically. These defects occur at significant frequencies with current state-of-the-art processes. Specifically, we discuss the importance of detecting these defects using KLA broadband plasma (BBP) optical inspection systems and the development of useful analysis methodologies. In addition, we describe use of traditional focus-dose process window discovery methodology developed on these optical inspection systems, for a foundry N5 equivalent M2 layer with both hybrid EUV and direct EUV patterning schemes. We highlight the impact of EUV stochastics to the overall process window.

Tumor Control and Quality of Life in Skin Cancer Patients With Extensive Multilayered Nasal Defects.

Objectives.The reconstruction after nasal skin cancer (NSC) resection is often practiced differently. The objective of this study is to evaluate the influence of patient-, tumor- and management-related factors on the role of surgery and choice of reconstruction.Methods.This was a monocentric retrospective study of patients who were diagnosed with a NSC (squamous cell or basal cell carcinoma) and suffered from an extended defect after ablative surgery between 2003 and 2013. Twenty-five patients were included. Tumors were staged using the Union for International Cancer Control (eighth edition) TNM classification for primary cutaneous skin cancer of the head and neck. Preferred treatment was surgery in all patients. Health-related quality of life (HRQoL) measurement was evaluated by one generic (36-Item Short Form Health Survey [SF-36]) and two organ-specific questionnaires (Rhinoplasty Outcome Evaluation [ROE] and Functional Rhinoplasty Outcome Inventory 17 [FROI-17]) after therapy. Survival data were estimated by the Kaplan-Meier method and statistical analysis was performed by log-rank, analysis of variance, Levene’s and t-tests. The median follow-up time was 2.1 years.Results.According to the Union for International Cancer Control classification, 13 of 25 tumors were staged as pT1 (52%), four as pT2 (16%), seven as pT3 (28%) and one as pT4a (4%). Seventy-two percent of patients (n=18) chose plastic reconstruction, and for the remaining 28% (n=7) of the patients opted for an implant-retained prosthesis. The overall survival was 69.5% after 5 years, the 5-year recurrence-free survival was 90.9% and the 5-year disease-specific survival was 100%. There was no significant difference in the HRQoL outcome between both rehabilitation methods.Conclusion.Surgery in NSC gives an excellent oncologic prognosis. Nasal reconstruction and prostheses are both very viable options depending on tumor stage and biology, the patient’s wishes as well as the experience of the surgeon.

Fast optimization of defect compensation and optical proximity correction for extreme ultraviolet lithography mask

Mask multilayer defect and optical proximity effect bring harmful impact on the imaging quality of extreme ultraviolet lithography. The undesirable impact could be compensated for by modification of the mask patterns. Based on machine learning and quasi-rigorous electromagnetic method, two fast simulation methods are utilized to accelerate the optimization of the defect compensation patterns. Defect compensation considering simultaneous optical proximity correction is also studied for further improvement of pattern fidelity. Combined with a well-performed evolutionary searching algorithm, the two fast simulation methods are adopted in the defect-compensation optimization for different mask patterns. Mask modification optimization considering both defect compensation and optical proximity correction is also demonstrated by a simulation study. Simulation results demonstrated the acceleration due to the adoption of the two fast simulation methods. Simulation results also validated that both the defect impact and the optical proximity effect can be compensated for under the same mask modification frame. The mask modification strategy combining the two fast simulation methods and the evolutionary algorithm provides a potential and flexible compensation approach for EUVL masks that influenced by multilayer defect and proximity effect.

Time‐Domain Topological Energy Imaging Method of Concrete Cavity Defect by Lamb Wave

This paper presents an ultrasonic Lamb wave imaging method based on time‐domain topological energy to address artifacts in the results of traditional ultrasound imaging methods. This method is based on topological theory and the calculation of the direct and adjoint sound fields in a defect‐free reference medium. It focuses the direct and adjoint sound fields at the cavity defect using time reversal and their time‐domain topological energy as the pixel values of the image to reduce the artifacts. The physical mechanism of time‐domain topological energy (TDTE) imaging is revealed by finite element simulation and experiment. The feasibility of this method for multilayer concrete cavity defect imaging is verified. Compared with the traditional synthetic aperture focusing technique (SAFT) imaging method, the numerical simulation and experimental results show that the method can overcome the influence of ultrasonic Lamb wave dispersion and locate cavity defects with high accuracy and few artifacts. These features indicate the potential of the method in imaging damage concrete structures.

Electronic excitations in transition metal dichalcogenide monolayers from an LDA+GdW approach

Monolayers of transition metal dichalcogenides (TMDCs) have unique optoelectronic properties. Density functional theory allows only for a limited description of the electronic excitation energies in these systems, while a more advanced treatment within many-body perturbation theory employing the $\mathit{GW}/\mathrm{BSE}$ approximation is often rather time consuming. Here, we show that the recently developed $\mathrm{LDA}+\mathit{GdW}$ approach provides an efficient and at the same time reliable description of one-particle energies, as well as optical properties including bound excitons in TMDCs. For five exemplary materials (${\mathrm{MoSe}}_{2}, {\mathrm{MoS}}_{2}, {\mathrm{WSe}}_{2}, {\mathrm{WS}}_{2}$, and ${\mathrm{ReSe}}_{2}$), we discuss the numerical convergence, in particular with respect to k-point sampling, and show that the $\mathit{GdW}/\mathrm{BSE}$ approximation gives results similar to common $\mathit{GW}/\mathrm{BSE}$ calculations. Such efficient approaches are essential to treat larger multilayer systems or defects.

Modulating acoustic Fano resonance of self-collimated sound beams in two dimensional sonic crystals

Controlling the lineshape of Fano resonance has great potential applications. Here we propose a type of acoustic Fano resonator, which is composed of a multi-layer zigzag line defects (ZLDs) sandwiched by double-layer zigzag steel rods in two-dimensional sonic crystals (SCs). We have theoretically and experimentally observed the asymmetric Fano resonances caused by the interference between the resonant and propagating self-collimated acoustic waves. It is demonstrated that the resonance dip frequency and Fano profile can be modulated by adjusting the structure parameters of the SC-based resonator. Our finding provides an efficient approach to manipulate sound propagation for future acoustic devices.

微分干涉差共焦显微膜层微结构缺陷探测系统

微分干涉差共焦显微膜层微结构缺陷探测系统

Notice of Retraction: Localization of Short and Open Defects in Multilayer Through Silicon Vias (TSV) Daisy-Chain Structures

Small form factors and high bandwidth are two imperatives nowadays for three-dimensional integrated circuits (3-D-ICs). These requirements can be achieved by the use of through silicon vias, by the reduction of their radius and, at the same time, of the pitch among them. Having a considerable number of devices in a limited space inevitably increases the probability of the creation of defects (short, open, void, etc.). The study of the nature, topology, and creation mechanism of defects is crucial for 3-D-IC design. This paper suggests a procedure able to determine the nature of a defect (open- or short-circuit) and to estimate its position, basing its approach on the study of the electrical parameters of the defected structure, avoiding the use of invasive method such as Lock-in Thermography. A daisy-chain structure is manufactured and open or short defects are intentionally placed along the channel. With and without defects, the equivalent capacitance and inductance are extracted from the S-Parameters, from measurement and three-dimensional electromagnetic simulations, and used to define and validate the proposed procedure.