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Chemical vapor deposition of graphene on refractory metals: The attempt of growth at much higher temperature
摘要： Large area graphene is usually grown by chemical vapor deposition on Cu or Ni catalysts at ～1000 °C. For most materials, high temperature leads to high quality. However, graphene growth at even higher temperatures is rarely reported. Therefore, here we systematically investigate the graphene deposition on refractory metals i.e. metals with extremely high melting points. The growth parameters and material characterizations are given in detail. On Ta which readily forms carbides during the carbon deposition, the growth mode is monolayer due to the chemical absorption of excess carbon in the bulk metal. On Re, there is no carbide formed (except in extreme conditions), which greatly simpli?es the scenario. Because of the relatively high carbon solubility in Re, the growth temperature has to be limited in order not to drift into the dominantly multilayer graphene regime caused by the carbon segregation. Graphene with reasonable quality has been achieved, although not as good as expected. For example, on Ta, the residual bonds between the graphene and substrate deteriorate the graphene crystalline quality. Despite the di?culties in refractory metal etching, the transfer technique of the graphene is also explored. This research contributes to the fundamental understanding of the graphene growth theory and technology on refractory metals.
关键词： Refractory metal,Graphene,Chemical vapor deposition,High temperature growth
更新于2025-09-23 15:23:52
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Photodynamic Therapy in the Treatment of Bladder Cancer: Past Challenges and Current Innovations
摘要： There are limited treatment options for patients with recurrent non-muscle-invasive bladder cancer. In this report, we will talk about the history of photodynamic therapy; although it showed encouraging therapeutic results, it was largely abandoned due to toxicity or bystander effects on normal cells. Monoclonal antibody-conjugates represent an emerging therapeutic approach for malignancies that improves upon tumor specificity. The use of a monoclonal antibody-photosensitizer conjugate is a more selective method of delivering light therapy and has been termed 'photoimmunotherapy', which we will discuss in the last part of this report.
关键词： Hematoporphyrin,Urothelial cancer,Hexaminolevulinic acid,Photoimmunotherapy,PIT,BCG-refractory NMIBC,PDT,Bladder cancer,5-Aminolevulinic acid,Photodynamic therapy
更新于2025-09-23 15:23:52
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Light Metals 2014 (Grandfield/Light) || N-SiC Side Lining - Variations of Materials Structure
摘要： The key process in fabrication of Nitride bonded silicon carbide side lining of reduction pots is the reaction between Nitrogen and Silicon. Silicon may react with Nitrogen in solid, liquid and gaseous phase. The reaction is strongly exothermal. Almost all N-SiC refractory materials of more or less big shapes have the gradients of porosity from middle to the edges. The reason for these gradients may be the overheating of the middle part of shapes, compared to near surface layers, due to the exothermal effect and consequent increased concentration of volatile Silicon. Volatile Silicon tends to move to areas of lower temperature and the gradients of porosity are 1-2 %, but sometimes it may reach 5-7%. The problems with side lining of reduction pots may be because of the design of the pots, due to the overheating of the bath, yet the structure of N-SiC materials might be also critical.
关键词： corrosion resistance,side lining,N-SiC refractory
更新于2025-09-23 15:22:29
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Calculating the Minimum Thickness of Glass Fuse by Zr Kα Line for Phosphorus-Containing Zircon-Refractory Material
摘要： In this paper, we take Zr Kα line as the analysis object due to the existence of overlapping phenomenon, which the zirconium La line (0.607nm) and phosphorus Ka line (0.615nm), in phosphorus-containing zircon-refractory material. We discovered and calculated the critical thickness of glass fuse by the theoretical calculation method, and we verified the feasibility of the theory. By experiment we found that critical thickness of glass fuse can be reduced by adding additives in flux. Conventional thickness of glass fuse can reaches a critical thickness by adding 20% of calcium oxide (in the form of calcium carbonate was added) in flux. This method could also increase significantly the measurement sensitivity to guarantee good result.
关键词： Zircon-refractory material,Minimum thickness,Zr Kα line
更新于2025-09-23 15:22:29
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Role of laser ablation in multimodal treatment of radioiodine- refractory bone metastases of thyroid cancer: a retrospective study
摘要： Purpose To assess the efficacy, safety, and pain benefits of imaging-guided laser ablation (IGLA) in patients with radioiodine-refractory (RR) bone metastases from differentiated thyroid carcinoma (DTC). Patients and methods The institutional medical records of patients with bone metastases from DTC treated with laser ablation (LA) were reviewed retrospectively. Local response, complications, and effects on pain relief were investigated. Results Six osteolytic lesions in five patients (one male, four females; mean age 65.4 ± 5.1 years, range 58–72) were treated with IGLA. All lesions were osteolytic and all have had previous treatments with high-dose radioiodine therapy followed by external radiotherapy (EBRT). All patients assumed opioid analgesics for severe pain. Overall, the lesions (mean size 5.8 ± 3.2 cm; median 5.0 cm, range 3.0–12.0 cm) underwent nine IGLA sessions (mean 1.8 ± 0.4 sessions; median 2.0 sessions, range 1–2). In four (80%) out five lesions, cross-sectional imaging showed a nearly complete response (CR) while the largest lesion was ablated by 80%. Pain changes were assessed with the Brief Pain Inventory-Short Form, that was administered before IGLA and during a 6-month follow-up. Patients experienced significant reduction in worst pain, average pain, and pain interference. Following IGLA, the average daily opioid requirement rapidly and progressively decreased. Treatments were well-tolerated and no major complications occurred. Conclusions IGLA is an effective and safe debulking procedure and provides significant pain relief in patients suffering from DTC bone metastases that are not responsive to standard treatments. So, IGLA could be considered as part of a multi-modality management of advanced thyroid cancer with RR metastatic skeletal involvement.
关键词： Minimally invasive techniques,Laser ablation,Differentiated thyroid cancer,Thermal ablation therapies,Radioiodine-refractory thyroid cancer,Bone metastases
更新于2025-09-23 15:21:01
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Development of laser ablation absorption spectroscopy for nuclear fuel materials: plume expansion behavior for refractory metals observed by laser-induced fluorescence imaging spectroscopy
摘要： The dynamic behavior of an ablation plume in low pressure rare gas ambient was investigated with laser-induced fluorescence imaging spectroscopy for three refractory metals, i.e. titanium, zirconium and hafnium. A comparison of the plume expansion behaviors for the species of these elements revealed an atomic weight effect on the plume structure formation. A hemispherical thin layer and cavity structure reported previously for gadolinium were observed also for these elements. It was found that the plume size increases as well as the layer thickness decreases with increasing atomic weight. For ground state atoms of Ti, substantial amount of atoms were observed even at the center of the plume. Also, the persistence of the Ti atomic plume was as long as 300 μs, which was significantly longer than the other species studied. Furthermore, the mass-dependent elemental separation was observed in the ablation plume produced from a multielement sample. These results suggest that the observed plume structure arises from the ion-electron recombination process and the recoil of the ablated species during the multiple collisions with gas atoms.
关键词： LIBS,Laser-induced fluorescence spectroscopy,Laser ablation,Ablation plume structure,Refractory metals
更新于2025-09-23 15:21:01
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Stabilizing the Plasmonic Response of Titanium Nitride Nanocrystals with a Silicon Oxynitride Shell: Implications for Refractory Optical Materials
摘要： We discuss the synthesis and properties of nanoparticles and thin films for refractory plasmonic applications. The approach focuses on titanium nitride (TiN), which overcomes the limitations of more common plasmonic materials like silver and gold with respect of temperature stability. Free-standing TiN-based nanoparticles are produced in two serially connected plasma reactors, where TiN nanocrystals are nucleated in a first plasma stage, then aerodynamically dragged in a second stage and conformally coated with a silicon nitride layer. An in-depth comparison between bare and coated TiN nanoparticles is presented in terms of the structural, chemical and optical properties. Coating of the titanium nitride core reduces its oxidation upon exposure to air, drastically improving plasmonic response. Thin films realized using the core-shell structure show practically no change in reflectivity even when the thin films are heated to 900°C in an inert atmosphere. This study introduces a simple surface passivation schemes that enhances the functionality of the material, providing further confirmation of the potential of nitride-based plasmonic material as high-quality refractory optical compounds for a broad range of applications.
关键词： Titanium nitride,Non-thermal plasma,Thin films,Nanocrystals,Refractory nanomaterials,Plasmonic nanomaterials
更新于2025-09-23 15:19:57
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The Role of Subthreshold Micropulse Yellow Laser as an Alternative Option for the Treatment of Refractory Postoperative Cystoid Macular Edema
摘要： Background: To evaluate the efficacy and the safety of subthreshold micropulse yellow laser (SMYL) in the treatment of chronic postoperative cystoid macular edema (PCME), which is refractory to standard therapies. Methods: A retrospective chart review of ten eyes of ten patients affected by refractory PCME who underwent SMYL was performed. Five PCME cases were subsequent to uncomplicated cataract surgery (CS), two cases to complicated CS (CCS) with posterior capsule rupture and three cases occurred after retinal detachment surgery (RD). All conditions were refractory to conventional treatments prior to SMYL interventions for at least 4 months, including nonsteroidal anti-inflammatory eyedrops, topical steroids, oral indomethacin, sub-Tenon’s triamcinolone injections and Dexamethasone intravitreal implants. All patients underwent one or more treatments with 577 nm SMYL photo-stimulation, with 7 × 7 grids with confluent spots and a 5% duty cycle covering the whole edematous retina, including the foveal center. Best corrected visual acuity (BCVA) and central macular thickness (CMT) were obtained using OCT, and evaluated before and after the treatment at 1, 2, 3 and 6-month follow-ups. Results: A complete subfoveal macular edema resolution was observed in all of the eyes, with statistically significant improvements in terms of BCVA and CMT in all of the follow-up timelines (at 6 months, p = 0.002 and p = 0.005, respectively). The mean number of laser treatments was 1.3. At the final follow-up, a complete subfoveal edema reabsorption was observed in all patients with visual acuity improvement. No complications were observed in any case. Conclusions: SMYL seems to be a safe and effective treatment for the long-term resolution of refractory PCME and may be a useful alternative to expensive and invasive therapeutic options.
关键词： micropulse yellow laser,cataract surgery,refractory macular edema,post-surgical cystoid macular edema
更新于2025-09-23 15:19:57
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Refractory plasmonics enabling 20% efficient lead-free perovskite solar cells
摘要： Core-shell refractory plasmonic nanoparticles are used as excellent nanoantennas to improve the efficiency of lead-free perovskite solar cells (PSCs). SiO2 is used as the shell coating due to its high refractive index and low extinction coefficient, enabling the control over the sunlight directivity. An optoelectronic model is developed using 3D finite element method (FEM) as implemented in COMSOL Multiphysics to calculate the optical and electrical parameters of plain and ZrN/SiO2-modified PSCs. For a fair comparison, ZrN-decorated PSCs are also simulated. While the decoration with ZrN nanoparticles boosts the power conversion efficiency (PCE) of the PSC from 12.9% to 17%, the use of ZrN/SiO2 core/shell nanoparticles shows an unprecedented enhancement in the PCE to reach 20%. The enhancement in the PCE is discussed in details.
关键词： lead-free perovskite solar cells,refractory plasmonics,ZrN/SiO2 core/shell nanoparticles,power conversion efficiency,optoelectronic modeling
更新于2025-09-23 15:19:57
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Micropulse Transscleral Diode Laser Cyclophotocoagulation in Refractory Glaucoma
摘要： Purpose: To assess the short-term ef?cacy and safety of micropulse transscleral diode laser cyclophotocoagulation (MP-TSCPC) in the management of refractory glaucoma and to compare outcomes based on prior glaucoma surgeries. Design: Retrospective analysis. Participants: Patients with refractory glaucoma who underwent MP-TSCPC at a single institution by 1 of 4 surgeons. Methods: Chart review of cases of MP-TSCPC using the Iridex Cyclo G6 (Mountain View, CA) laser with standard parameters and laser duration at the discretion of each treating physician. Main Outcome Measures: Probability of postoperative success was estimated by the Kaplan-Meier method. Success parameters included intraocular pressure (IOP) 6 to 21 mmHg with or without topical antihypertensive therapy, 20% or more IOP reduction from baseline for any 2 consecutive visits after 3 postoperative months, and no subsequent glaucoma surgery. Results: One hundred sixteen eyes of 116 patients (mean age, 65.8±16.9 years) were included. Baseline IOP was 22.2±7.9 mmHg, and mean postoperative follow-up time was 6.3±3.4 months (range, 3e12 months.) Postoperative IOP at the ?nal follow up was 15.3±6.6 mmHg (P < 0.01), corresponding to a reduction of approximately 6.9 mmHg (31.1%). Most eyes (66.4%) underwent at least 6 months of follow-up. Short-term probability of success was 93.1% at 3 months and 74.3% at 6 months. Eyes that had undergone prior traditional glaucoma surgery (trabeculectomy, tube shunt, excessive pressure-regulating shunt system miniature glaucoma shunt [Alcon, Fort Worth, TX], or a combination thereof) demonstrated a higher probability of success (67.6%) compared with eyes that had not (41.4%; P ? 0.014). The most common complications were decline in best-corrected visual acuity (7.8%) and hypotony (1.7%). Conclusions: Micropulse transscleral diode laser cyclophotocoagulation has a signi?cant short-term ocular hypotensive effect and favorable safety pro?le in eyes with refractory glaucoma. The probability of successful outcome was greater in eyes that had undergone prior traditional glaucoma surgery. Ophthalmology Glaucoma 2019;-:1e11 a 2019 by the American Academy of Ophthalmology
关键词： efficacy,micropulse transscleral diode laser cyclophotocoagulation,intraocular pressure,safety,refractory glaucoma
更新于2025-09-12 10:27:22