Blank Defects Research Articles

Compensation of EUV lithography mask blank defect based on an advanced genetic algorithm.

Mask blank defect is one of the most important factors that degrades the image quality of extreme ultraviolet (EUV) lithography system, and further leads to a yield lose. In order to compensate the amplitude and phase distortions caused by the EUV mask blank defects, this paper proposes an advanced algorithm to optimize the mask absorber pattern based on genetic algorithm. First, a successive approximation correction method is used to roughly compensate the effect of mask blank defect. Then, an advanced genetic algorithm is proposed to obtain higher efficiency and compensation accuracy, which uses an adaptive coding strategy and a fitness function considering normalized image log slope of lithography image. For illustration, the proposed method is verified based on rectangular contact patterns and complex pattern with different defects. The aerial images of optimized masks are evaluated by a commercial lithography simulator. It will show that the proposed method can mitigate the impact of mask defects, and improve the fidelity of lithography print image. The simulation results also demonstrate the higher convergence efficiency and mask manufacturability can be guaranteed by the proposed method.

Construction of Microunits by Adipose-Derived Mesenchymal Stem Cells Laden with Porous Microcryogels for Repairing an Acute Achilles Tendon Rupture in a Rat Model.

ObjectiveTissue engineering approaches seem to be an attractive therapy for tendon rupture. Novel injectable porous gelatin microcryogels (GMs) can promote cell attachment and proliferation, thus facilitating the repair potential for target tissue regeneration. The research objectives of this study were to assess the efficacy of tissue-like microunits constructed by multiple GMs laden with adipose-derived mesenchymal stem cells (ASCs) in accelerated tendon regeneration in a rat model.MethodsThrough a series of experiments, such as isolation and identification of ASCs, scanning electron microscopy, mercury intrusion porosimetry (MIP), laser scanning confocal microscopy and the CCK-8 test, the biocompatibility of GMs was evaluated. In an in vivo study, 64 rat right transected Achilles tendons were randomly divided into four groups: the ASCs+GMs group (microunits aggregated by multiple ASC-laden GMs injected into the gap), the ASCs group (ASCs injected into the gap), the GMs group (GMs injected into the gap) and the blank defect group (non-treated). At 2 and 4 weeks postoperatively, the healing tissue was harvested to evaluate the gross observation and scoring, biomechanical testing, histological staining and quantitative scoring. Gait analysis was performed over time. The 64 rats were randomly assigned into 4 groups: (1) micro-unit group (ASCs+GMs) containing ASC (105)-loaded 120 GMs in 60 μL DMEM; (2) cell control group (ASCs) containing 106 ASCs in 60 μL DMEM; (3) GM control group (GMs) containing 120 blank GMs in 60 μL DMEM; (4) blank defect group (Defect) containing 60 μL DMEM, which were injected into the defect sites. All animals were sacrificed at 2 and 4 weeks postsurgery (Table 1).ResultsIn an in vitro study, GMs (from 126 μm to 348 μm) showed good porosities and a three-dimensional void structure with a good interpore connectivity of the micropores and exhibited excellent biocompatibility with ASCs. As the culture time elapsed, the extracellular matrix (ECM) secreted by ASCs encased the GMs, bound multiple microspheres together, and then formed active tendon tissue-engineering microunits. In animal experiments, the ASCs+GMs group and the ASCs group showed stimulatory effects on Achilles tendon healing. Moreover, the ASCs+GMs group was the best at improving the macroscopic appearance, histological morphology, Achilles functional index (AFI), and biomechanical properties of repair tissue without causing adverse immune reactions.ConclusionPorous GMs were conducive to promoting cell proliferation and facilitating ECM secretion. The ASCs-GMs matrices showed an obvious therapeutic efficiency for Achilles tendon rupture in rats.

Characterisation and evaluation of the regenerative capacity of Stro-4+ enriched bone marrow mesenchymal stromal cells using bovine extracellular matrix hydrogel and a novel biocompatible melt electro-written medical-grade polycaprolactone scaffold

Many skeletal tissue regenerative strategies centre around the multifunctional properties of bone marrow derived stromal cells (BMSC) or mesenchymal stem/stromal cells (MSC)/bone marrow derived skeletal stem cells (SSC). Specific identification of these particular stem cells has been inconclusive. However, enriching these heterogeneous bone marrow cell populations with characterised skeletal progenitor markers has been a contributing factor in successful skeletal bone regeneration and repair strategies. In the current studies we have isolated, characterised and enriched ovine bone marrow mesenchymal stromal cells (oBMSCs) using a specific antibody, Stro-4, examined their multipotential differentiation capacity and, in translational studies combined Stro-4+ oBMSCs with a bovine extracellular matrix (bECM) hydrogel and a biocompatible melt electro-written medical-grade polycaprolactone scaffold, and tested their bone regenerative capacity in a small in vivo, highly vascularised, chick chorioallantoic membrane (CAM) model and a preclinical, critical-sized ovine segmental tibial defect model.Proliferation rates and CFU-F formation were similar between unselected and Stro-4+ oBMSCs. Col1A1, Col2A1, mSOX-9, PPARG gene expression were upregulated in respective osteogenic, chondrogenic and adipogenic culture conditions compared to basal conditions with no significant difference between Stro-4+ and unselected oBMSCs. In contrast, proteoglycan expression, alkaline phosphatase activity and adipogenesis were significantly upregulated in the Stro-4+ cells. Furthermore, with extended cultures, the oBMSCs had a predisposition to maintain a strong chondrogenic phenotype. In the CAM model Stro-4+ oBMSCs/bECM hydrogel was able to induce bone formation at a femur fracture site compared to bECM hydrogel and control blank defect alone. Translational studies in a critical-sized ovine tibial defect showed autograft samples contained significantly more bone, (4250.63 mm3, SD = 1485.57) than blank (1045.29 mm3, SD = 219.68) ECM-hydrogel (1152.58 mm3, SD = 191.95) and Stro-4+/ECM-hydrogel (1127.95 mm3, SD = 166.44) groups.Stro-4+ oBMSCs demonstrated a potential to aid bone repair in vitro and in a small in vivo bone defect model using select scaffolds. However, critically, translation to a large related preclinical model demonstrated the complexities of bringing small scale reported stem-cell material therapies to a clinically relevant model and thus facilitate progression to the clinic.

In vivo bone regeneration assessment of offset and gradient melt electrowritten (MEW) PCL scaffolds

BackgroundBiomaterial-based bone tissue engineering represents a promising solution to overcome reduced residual bone volume. It has been previously demonstrated that gradient and offset architectures of three-dimensional melt electrowritten poly-caprolactone (PCL) scaffolds could successfully direct osteoblast cells differentiation toward an osteogenic lineage, resulting in mineralization. The aim of this study was therefore to evaluate the in vivo osteoconductive capacity of PCL scaffolds with these different architectures.MethodsFive different calcium phosphate (CaP) coated melt electrowritten PCL pore sized scaffolds: 250 μm and 500 μm, 500 μm with 50% fibre offset (offset.50.50), tri layer gradient 250–500-750 μm (grad.250top) and 750–500-250 μm (grad.750top) were implanted into rodent critical-sized calvarial defects. Empty defects were used as a control. After 4 and 8 weeks of healing, the new bone was assessed by micro-computed tomography and immunohistochemistry.ResultsSignificantly more newly formed bone was shown in the grad.250top scaffold 8 weeks post-implantation. Histological investigation also showed that soft tissue was replaced with newly formed bone and fully covered the grad.250top scaffold. While, the bone healing did not happen completely in the 250 μm, offset.50.50 scaffolds and blank calvaria defects following 8 weeks of implantation. Immunohistochemical analysis showed the expression of osteogenic markers was present in all scaffold groups at both time points. The mineralization marker Osteocalcin was detected with the highest intensity in the grad.250top and 500 μm scaffolds. Moreover, the expression of the endothelial markers showed that robust angiogenesis was involved in the repair process.ConclusionsThese results suggest that the gradient pore size structure provides superior conditions for bone regeneration.

Nanocomposite scaffold seeded with mesenchymal stem cells for bone repair.

The mechanical property of bone tissue scaffolds is one of the most important aspects in bone tissue engineering that has remained problematic. In our previous study, we fabricated a three-dimensional scaffold from nano-hydroxyapatite/gelatin (nHA/Gel) and investigated its efficiency in promoting bone regeneration both in vitro and in vivo. In the present study, the effect of adding silicon carbide (SiC) on the mechanical and biological behaviors of the nHA/Gel/SiC and bone regeneration in vivo were determined. nHA and SiC were synthesized and characterized by the X-ray diffraction pattern and transmission electron microscope image. Layer solvent casting, freeze drying, and lamination techniques were applied to prepare these scaffolds. Then, the biocompatibility and cell adhesion behavior of the synthesized nHA/Gel/SiC scaffolds were investigated. For in vivo studies, rats were categorized into three groups: blank defect, blank scaffold, and rat bone marrow mesenchymal stem cells (rBM-MSCs)/scaffold. After 1, 4, and 12 weeks post-injury, the rats were sacrificed and the calvaria were harvested. Sections with a thickness of 5 µm thickness were prepared and stained with hematoxylin-eosin and Masson's Trichrome, and immunohistochemistry was performed. Our results showed that SiC effectively increased the mechanical properties of the nHA/Gel/SiC scaffold. No significant differences were observed in biocompatibility, cell adhesion, and cytotoxicity of the nHA/Gel/SiC in comparison with the nHA/Gel nanocomposite. Based on histological and immunohistochemical studies, both osteogenesis and collagenization were significantly higher in the rBM-MSCs/scaffold group, quantitatively and qualitatively. The present study strongly suggests the potential of SiC as an alternative strategy to improve the mechanical and biological properties of bone tissue engineering scaffolds, and shows that the pre-seeded nHA/Gel/SiC scaffold with rBM-MSCs improves osteogenesis in the engineered bone implant.

The Obliteration of Noncritical Size Bone Defects With Bone Dust or Bone Replacement Material (Bioactive Glass S53P4).

Bone dust (BD) harvested during operation may be suitable as an autologous obliteration material for noncritical size defects. Bioactive glass (BA) can be an alternative. To treat noncritical size defects, BD and BA are commonly used for obliteration techniques. However, the optimal harvesting method and parameters for BD have not been examined. In this study, we analyzed the osseoregenerative potential of both materials. Thirteen female merino sheep (7-yr old) underwent surgery on the frontal calvaria. Three defects were inserted. The first defect was considered a reference and remained unfilled, the second defect was filled with BD from the calvaria bone, and the third defect was filled with BA S53P4. The animals were sacrificed after 3 weeks. To evaluate bone regeneration, we used digital volume tomography, bone density measurement, fluorochrome sequence labeling, and histological analysis. All analyses showed quantitative and qualitative bone regeneration 3 weeks after operation. The control blank defect showed significantly less new bone growth than the BD-filled defect. Moreover, bone regeneration occurred from the surrounding bone and showed only a defect bridge in the BD-filled defect. The BA completely filled the defect and had the highest density although the same amount of new mineralized bone generated as in the reference. BD and BA seemed to be suitable bone replacement materials for obliteration techniques because they completely filled the defects. Thus, BD harvested under standardized conditions provided a higher level of osteoreparation potential for the generation of woven bone and establishment of defect bridges.

Investigation of blank bow defect after roller leveller by finite element analysis

Sheet metal often shows curvature, shape defects and internal (residual) stresses which are not complying with the increasing requirements for the quality needed for customers. Roller levelling is one of the ways to flatten a metal sheets. The setting up of such machines is extremely complex and mainly depends on the operator’s experience. The main objective of this paper is investigation of adjustable parameters of roller leveller together with elastic-plastic material behaviour on the internal stresses formation. High and unbalanced values of residual stresses lead to blank bow defects in a final product. In this study, numerical finite element (FE) 2D-model of roller levelling process is proposed to use. Properties of the material were determined experimentally. The blank bow magnitude was simulated and compared with experimental results and have a good accuracy for FE prediction.

A Biomimetic Alternative to Synthetic Hydroxyapatite: "Boron-Containing Bone-Like Hydroxyapatite" Precipitated From Simulated Body Fluid.

Biological hydroxyapatite (HA), has several mechanical and physical advantages over the commercially available synthetic apatite (CAP-HA). The aim of this in vivo study was to investigate the effect of osteoinductive "bone-like hydroxyapatite" obtained from simulated body fluid (SBF) combined with osteoinductive "boron" (B) on bone healing. Bone like nanohydroxyapatite (SBF-HA) was precipitated from 10× simulated body fluid (10×SBF). Thirty Sprague-Dawley rats were randomly divided into 5 experimental groups (n = 6 each). The groups were involving blank defect, chitosan, SBF-HA, SBF-HA/B, and CAP-HA. Two biparietal round critical sized bone defect was created using a dental burr. The rats were sacrificed respectively at the end of second and fourth months after surgery and their calvarium were harvested for further macroscopic, microtomographic, and histologic evaluation. The SBF-HA/B group demonstrated the highest mineralized matrix formation rates (30.69 ± 3.73 for the second month, 62.68 ± 7.03 for the fourth month) and was significantly higher than SBF-HA and the CAP-HA groups. The SBF-HA/B group demonstrated the highest mineralized matrix formation rates (30.69 ± 3.73 for the second month, 62.68 ± 7.03 for the fourth month) and was significantly higher than SBF-HA and the CAP-HA groups. In means of bone defect repair histologically, the highest result was observed in the SBF-HA/B group (P < 0.001). The "bone-like hydroxapatite" obtained from simulated body fluid is worth attention when both its beneficial effects on bone healing and its biological behavior is taken in consideration for further bone tissue engineering studies. It appears to be a potential alternative to the commercially available hydroxyapatite samples.

Osteogenic potential of recombinant human bone morphogenetic protein-9/absorbable collagen sponge (rhBMP-9/ACS) in rat critical size calvarial defects.

It has been reported that bone morphogenetic protein (BMP)-9 has potent osteoinductive properties among the BMP family by adenovirus-transfection experiments. We very recently reported that absorbable collagen sponge (ACS) as a carrier for recombinant human (rh) BMP-9, compared with chitosan sponge, was suitable for inducing bone healing/regeneration by BMP-9 in a rat calvarial defect model. The aim of this study was to evaluate different doses of rhBMP-9/ACS on new bone formation in rat critical size calvarial defects. Bilateral calvarial defects (n=32) were surgically created in 16 wistar rats and randomly filled with one of the following materials: (1) absorbable collagen sponge (ACS) alone; (2) 1μg-rhBMP-9/ACS (L-rhBMP-9/ACS); (3) 5μg-rhBMP-9/ACS (H-rhBMP-9/ACS); and (4) blank defects (control). The animals were sacrificed 8weeks postsurgery for radiographic and histomorphometric analyses. Bone volume and defect closure were statistically higher in the rhBMP-9/ACS-implanted (L-rhBMP-9/ACS and H-rhBMP-9/ACS) groups when compared with ACS-alone group (p<0.05). Furthermore, defects filled with H-rhBMP-9/ACS showed the highest levels of newly formed bone area (NBA) and NBA/total defect area among all groups. No significant differences in any of the radiographic and histometric parameters could be observed between both concentrations of rhBMP-9. Within the limits of this study, it can be concluded that rhBMP-9/ACS-induced bone formation can be reached with as little as 1μg/site in rat critical size calvarial defects. RhBMP-9 could be a potential therapeutic growth factor for future bone regenerative procedures.

Poly(L-Lactide)/Poly(∊-Caprolactone) and Collagen/β-Tricalcium Phosphate Scaffolds for the Treatment of Critical-Sized Rat Alveolar Defects: A Microtomographic, Molecular-Biological, and Histological Study

To determine the efficacy of a newly developed scaffold (col/β-TCP) in a preclinical rat model as compared with the gold standard treatment (autograft) and control scaffolds (PLLA/PCL). Fifty-six Sprague-Dawley rats were randomized into four experimental groups, and critical-sized alveolar defects (7 × 4 × 3 mm) were created in each animal. Group A was the blank defect group, group B received autograft, group C received col/β-TCP scaffolds, and group D received PLLA/PCL blend scaffolds to fill the bone defects. New bone formation was assessed radiomorphometrically, histomorphometrically, and molecular-biologically at 1 and 4 months following surgery. Radiomorphometrically, the best new bone volume rate at 1 month (43.7%) and 4 months (45.4%) was observed in the autograft group, and the difference was significantly higher than in the other three groups (P < .005, P < .001, P < .001 for 1 month and P = .004, P < .001, P < .001 for 4 months). Even though the new bone volume rate in the col/β-TCP group (21.5%) was higher than that of the PLLA/PCL group (18.2%), the difference was not significant (P = .08). Molecular-genetic analysis revealed significantly higher BSP and ALP gene expression levels in the autograft and col/β-TCP groups than in the blank defect group (P = .002 and P = .004). The engineered tissue scaffolds described herein have great potential as an alternative treatment option when cost, donor region morbidity, and duration of hospitalization are considered.

Toward defect-free fabrication of extreme ultraviolet photomasks

Defect-free fabrication of extreme ultraviolet (EUV) masks relies on the appropriate detection of native defects and subsequent strategies for their elimination. Commercial unavailability of actinic mask-blank inspection systems motivates the identification of an optical inspection methodology most suitable for finding relevant EUV blank defects. Studies showed that 193-nm wavelength inspection found the greatest number of printable defects as compared with rival higher-wavelength systems, establishing deep ultraviolet inspections as the blank defectivity baseline for subsequent mitigation strategies. Next, defect avoidance via pattern shifting was explored using representative 7-nm node metal/contact layer designs and 193-nm mask-blank inspection results. It was found that a significant percentage of native defects could be avoided only when the design was limited to active patterns (i.e., layouts without dummy fill). Total pattern-defect overlap remained ≤5 when metal layer blanks were chosen from the top 35% least defective substrates, while the majority of blanks remained suitable for contacts layers due to a lower active pattern density. Finally, nanomachining was used to address remaining native/multilayer defects. Native catastrophic defects were shown to recover 40% to 70% of target critical dimension after nanomachining, demonstrating the enormous potential for compensating multilayer defects.

Repair of rat critical size calvarial defect using osteoblast-like and umbilical vein endothelial cells seeded in gelatin/hydroxyapatite scaffolds.

The present study used a previously developed three-dimensional Gelatin/Hydroxyapatite (Gel/HA) homogeneous nanocomposite scaffold with porosity of 82% and interconnecting pores ranging from 300 to 500 μm. Cell-seeded scaffolds were used to evaluate bone regeneration of rat critical-size calvarial defect. Totally, 36 male Wistar rats were randomly divided into four experimental groups, including blank defect (defects without any graft), blank scaffold (defects filled with Gel/HA scaffold without cells), and two groups of cell-seeded scaffolds (defects filled with either Gel/HA scaffold seeded with osteoblast-like and endothelial cells or osteoblast-like cell-seeded constructs). After 1, 4, and 12 weeks of scaffold implantation, rats were sacrificed and the calvaria were harvested for histological, immunohistochemical and histomorphometric analysis. In vitro tests showed that scaffolds were nontoxic to cells and promoted ideal cellular attachment. In vivo investigation on scaffold revealed that blank calvarial defects indicated incomplete tissue coverage and little evidence of bone healing. However, blank scaffold and cell-seeded scaffolds significantly promoted osteoconduction and ostegogenesis. Taken together, pre-seeded Gel/HA nanocomposite scaffold with osteoblasts and endothelial cells presented an effective combination to improve osteogenesis in the engineered bone implant. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1770-1778, 2016.

Extreme ultraviolet multilayer defect analysis and geometry reconstruction

This paper proposes a method for the characterization of multilayer defects from extreme ultraviolet (EUV) projection images at different focus positions. The transport-of-intensity equation is applied to retrieve the phase distribution of the reflected light in the vicinity of the defect. The defect-induced intensity and phase modifications and their dependency from defect geometry parameters are analyzed by several selected optical properties of multilayer defect. To reconstruct the defect geometry parameters from the intensity and phase of a defect, a principal component analysis (PCA) is employed to parameterize the intensity and phase distributions into principal component coefficients. In order to construct the base functions of the PCA, a combination of a reference multilayer defect and appropriate pupil filters is introduced to obtain the designed sets of intensity and phase distributions. Finally, an artificial neural network is applied to correlate the principal component coefficients of the intensity and the phase of the defect with the defect geometry parameters and to reconstruct the unknown defect geometry parameters. The performance of the proposed approach is evaluated both for mask blank defects and for defects in the vicinity of an absorber pattern.

Conjunctival structural and functional reconstruction using acellular bovine pericardium graft (Normal GEN®) in rabbits.

To evaluate the effectiveness of acellular bovine pericardium grafts (Normal GEN®) used as scaffolds for conjunctival reconstruction. The acellular bovine pericardium graft and the amnion graft were implanted into the bulbar conjunctival defects of adult rabbits. Conjunctival samples of implanted materials and blank defect controls were observed at day 3, 7, 14, 21, 28, and 56 postoperatively. Histological examination was observed at day 14, 28, and 56 of surgery, including hematoxylin-eosin staining, periodic acid-Schiff staining, and Masson's trichrome staining, while immunofluorescent microscopy was observed at 14days and 28days after surgery. Results were compared among the Normal GEN®, amnion, and blank defect controls. All three groups showed complete conjunctival reconstruction. Wounds that were not grafted closed by formation of conjunctival scar characterized by a linear array of densely packed collagen fibers in Tenon's capsule. Subepithelial tissue in the grafted groups comprised a loosely organized network of randomly oriented collagen that resembled that of the normal bulbar conjunctiva. However, there was a dense layer of aligned collagen between the conjunctival Tenon's capsule and the sclera in the NormalGEN® group, about 250μm in thickness. Implantation of the NormalGEN® graft promoted the formation of conjunctiva as a kind of scaffold both in structure and in function. It had more advantageous mechanical properties than the amnion, strong and elastic, during the period of conjunctival reconstruction.

Evaluating printability of buried native extreme ultraviolet mask phase defects through a modeling and simulation approach

Since completely defect-free masks will be hard to achieve, it is essential to have a good understanding of the printability of the native extreme ultraviolet (EUV) mask defects. In this work, we performed a systematic study of native mask defects to understand the defect printability they cause. The multilayer growth over native substrate mask blank defects was correlated to the multilayer growth over regular-shaped defects having similar profiles in terms of their width and height. To model the multilayer growth over the defects, a multilayer growth model based on a level-set technique was used that took into account the tool deposition conditions of the Veeco Nexus ion beam deposition tool. Further, the printability of the characterized native defects was studied at the SEMATECH-Berkeley Actinic Inspection Tool (AIT), an EUV mask-imaging microscope at Lawrence Berkeley National Laboratory. Printability of the modeled regular-shaped defects, which were propagated up the multilayer stack using level-set growth model, was studied using defect printability simulations implementing the waveguide algorithm. Good comparison was observed between AIT and the simulation results, thus demonstrating that multilayer growth over a defect is primarily a function of a defect’s width and height, irrespective of its shape.

Level-set multilayer growth model for predicting printability of buried native extreme ultraviolet mask defects

The availability of defect-free masks is considered to be a critical issue for enabling extreme ultraviolet lithography (EUVL) as the next generation technology. Since completely defect-free masks will be hard to achieve, it is essential to have a good understanding of the printability of EUV mask defects. In this work, two native mask blank defects were characterized using atomic force microscopy (AFM) and cross-section transmission electron microscopy (TEM), and the defect printability of the characterized native mask defects was evaluated using simulations implementing the finite-difference time-domain and the waveguide algorithms. The simulation results were compared with through-focus aerial images obtained at the SEMATECH Berkeley Actinic Inspection Tool (AIT), an EUV mask-imaging microscope at Lawrence Berkeley National Laboratory. The authors found agreement between the through-focus simulation results and the AIT results. To model the Mo/Si multilayer growth over the native defects, which served as the input for the defect printability simulations, a level-set technique was used to predict the evolution of the multilayer disruption over the defect. Unlike other models that assume a constant flux of atoms (of materials to be deposited) coming from a single direction, this model took into account the direction and incident fluxes of the materials to be deposited, as well as the rotation of the mask substrate, to accurately simulate the actual deposition conditions existing inside the ion beam deposition tool. The modeled multilayer growth was compared to the cross-section TEM images through the defects, as well as to the AFM scans for the given defects, and a good agreement was observed between them.

Comprehensive defect avoidance framework for mitigating extreme ultraviolet mask defects

Defect avoidance methods are likely to play a key role in overcoming the challenge of mask blank defectivity in extreme ultraviolet (EUV) lithography. In this work, we propose an innovative EUV mask defect avoidance method. It is the first approach that allows exploring all the degrees of freedom available for defect avoidance (pattern shift, rotation and mask floorplanning). We model the defect avoidance problem as a global, nonconvex optimization problem and then solve it using a combination of random walk and gradient descent. For a 8-nm polysilicon layer of an ARM Cortex M0 layout, our method achieves a 60% point better mask yield compared to prior art in defect avoidance for a 40-defect mask. We show that pattern shift is the most significant degree of freedom for improving mask yield. Rotation and mask floorplanning can also help improve mask yield to a certain extent.

PREDICTION AND EVALUATION OF THE MOLDS STATE USING THE TOOLS OF ARTICICIAL INTELLIGENCE

In this paper is presented part of the results from grant project, which is concern the area of primary cooling in continuous steel casting device, especially crystallizer’s surface quality. It was presented part results from crystallizer’s defect catalogue and Methodology of their evaluation. In terms of this paper was presented a method to evaluate narrow crystallizer’s desk qualities, which are dismantled when they are in maintenance department. In this paper is described proposal and development of monitoring and information system for support of crystallizer maintenance control and increase quality of processes which are performing basic functions of monitoring and localization of crystallizer’s desks, crystallizer lifetime prediction and prediction of blank defects. Target of the system is to optimize preventive maintenance of crystallizers desks, with utilizing maximum count of relevant data from technological and maintenance processes. The Department of Automation and Computing in Metallurgy, VSB-TU Ostrava has long dealt with the challenge of life of technical systems. In the frame of this solution it is solved an area of metallurgical objects life. One of these objects is the mold of the continuous steel casting device. The current solution results shows that is necessary to use knowledge, not based only on objective qualitative knowledge, so then knowledge subjective and heuristics. The results are the constructions processes using effective model structures, the same principles which utilize human experts. This approach to solving complex systems leading to deployment of systems based on artificial intelligence methods.

Osteogenic properties of PBLG-g-HA/PLLA nanocomposites.

New development of biomaterial scaffolds remains a prominent issue for the regeneration of lost or fractured bone. Of these scaffolds, a number of bioactive polymers have been synthesized and fabricated for diverse biological roles. Although recent evidence has demonstrated that composite scaffolds such as HA/PLLA have improved properties when compared to either HA or PLLA alone, recent investigations have demonstrated that the phase compatibility between HA and PLLA layers is weak preventing optimal enhancement of the mechanical properties and making the composites prone to breakdown. In the present study, poly (γ-benzyl-L-glutamate) modified hydroxyapatite/(poly (L-lactic acid)) (PBLG-g-HA/PLLA) composite scaffolds were fabricated with improved phase compatibility and tested for their osteogenic properties in 18 Wistar female rats by analyzing new bone formation in 3 mm bilateral femur defects in vivo. At time points, 2, 4 and 8 weeks post surgery, bone formation was evaluated by µ-CT and histological analysis by comparing 4 treatment groups; 1) blank defect, 2) PLLA, 3) HA/PLLA and 4) PBLG-g-HA/PLLA scaffolds. The in vivo analysis demonstrated that new bone formation was much more prominent in HA/PLLA and PBLG-g-HA/PLLA groups as depicted by µ-CT, H&E staining and immunohistochemistry for collagen I. TRAP staining was also utilized to determine the influence of osteoclast cell number and staining intensity to the various scaffolds. No significant differences in either staining intensity or osteoclast numbers between all treatment modalities was observed, however blank defects did contain a higher number of osteoclast-like cells. The results from the present study illustrate the potential of PBLG-g-HA/PLLA scaffolds for bone tissue engineering applications by demonstrating favorable osteogenic properties.

Study on Deformation Law of Drum-Shaped Blank and Collapse Defect in Rolling Process

Based on the FEM software simufact.forming, a finite element model of the radial-axial ring rolling for one ring product was constructed and the rolling process under different drum-shaped blanks were simulated in this paper, which revealed the variation of drum-shaped blank in the rolling process, analyzed the formation process and further proposed measures of eliminating collapse defect. The results show that the drum disappearing rate in initial rolling stage is greater than in later stage and it becomes increasingly difficult to disappear, which leads to collapse defect in the end. The drum-shape can be reduced by greater radial feed in initial rolling stage in the case of small drum-shape or rounding before rolling on ring rolling machine in the case of large drum-shape for avoiding collapse defect. The results provide valuable guiding significance for practical production.