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Kinking effects and transport properties of coaxial BN-C nanotubes as revealed by <i>in situ</i> transmission electron microscopy and theoretical analysis
摘要： The insights into transport behavior and the effects of bending on heterostructures constructed from boron nitride (BN) and carbon (C) nanotubes are important for their flexible device applications because the two systems have equally excellent mechanical but completely different electrical properties. In this work, coaxial BN–C nanotubes have been fabricated and their intrinsic transport properties, as well as structural and electrical response to bending deformation, are studied inside a high-resolution transmission electron microscope. Ballistic, diffusive, and hopping transports within different tube length ranges have been observed. When bending deformation was applied to the tubes, although severe kinking becomes apparent, their transport properties are not notably affected. Meanwhile, both theoretical and experimental analyses confirm that the kink positions depend on the ratio of tube diameter to its length. Possible formation of quantum dots, directly within the kink areas, was predicted through calculations of electron density redistribution between nanotube walls at bending.
关键词： bending deformation,transport properties,BN-C nanotubes,in situ TEM,quantum dots
更新于2025-09-11 14:15:04
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Investigations of the peritectic reaction and transformation in a hypo-peritectic steel: Using high-temperature confocal scanning laser microscopy and differential scanning calorimetry
摘要： The present work focuses on the peritectic reaction and transformation in a commercial hypo-peritectic steel. This multiple phase transformation was studied by means of the high temperature confocal scanning laser microscopy (HTCSLM) and the di?erential scanning calorimetry (DSC) analysis. The results indicate that the technique of combining HTCSLM and DSC can e?ectively distinguish and characterize the peritectic reaction and transformation. The results of these two methods verify and complement each other in interpreting the peritectic reaction and transformation. In situ observation of HTCSLM reveals that the austenite → δ-ferrite transformation during the continuous heating ?rstly occurred around the inclusion and at austenite grain boundary. The emerging δ/γ interfaces travel through previous γ grains by a ?nger-like morphology. With further heating, the unstable liquid phase formed by the peritectic reaction transforms into the δ-ferrite phases again. These stable δ-ferrite phases subsequently melt into liquid phase. During the peritectic solidi?cation, in situ observation reveals that the peritectic reaction is ?rstly observed to occur at the junction interface of the liquid phase and δ-ferrite phase. The γ intermediate phase propagates and thickens toward the liquid phase side and the δ-ferrite phase side in the subsequent peritectic transformation. The δ-ferrite and γ phases were observed to coexist in solid phase when the peritectic transformation ?nishes. Based on the linear regression of DSC results, it is found that the activation energy of the peritectic reaction is larger than that of the other phase transformations during heating, but it is on the contrary during cooling.
关键词： Peritectic reaction and transformation,In situ observation,DSC measurement,Hypo-peritectic steel,Continuous casting
更新于2025-09-11 14:15:04
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Stability of corneal topography and aberrometry after hyperopic laser in situ keratomileusis with a 500-Hz excimer laser platform: A 3-year follow-up study
摘要： The aim of this study is to analyze the long-term stability of the corneal topography, the functional optical zone, and the refractive stability throughout 3 years following laser in situ keratomileusis surgery for hyperopia using a 500-Hz excimer laser system. This retrospective consecutive observational case series study comprised 66 eyes that underwent laser in situ keratomileusis to correct hyperopia with a postoperative follow-up of 3 years. Laser in situ keratomileusis procedures were performed using the SCHWIND Amaris 500-Hz excimer laser. Main outcomes measured were stability of the functional optical zone at corneal topography and corneal aberrometry. Statistically significant differences were found in simulated keratometry (K2 (steep meridian) and Km (mean keratometry)) between 3 and 36 months postoperatively (p ? 0.01); these differences disappeared at 12 and 36 months (p ? 0.18). No statistically significant changes were observed in the horizontal and vertical diameter of the functional optical zone throughout the whole follow-up (p ? 0.07). A statistically significant difference was found in the spherical aberration between 3 and 36 months (p = 0.02); this difference disappeared when compared between 12 and 36 months (p = 0.72). Statistically significant correlations were detected between the vertical functional optical zone and coma root mean square (r = –0.510, p < 0.01) and between the vertical functional optical zone and spherical aberration (r = 0.441, p = 0.02) 36 months after surgery. Following 3 years of hyperopic laser in situ keratomileusis with a 500-Hz Amaris excimer laser, keratometry, functional optical zone, and corneal aberrations remain stable from 1 year after surgery. Topographical regression is not observed in hyperopic laser in situ keratomileusis with this excimer laser technology from 1 year after surgery.
关键词： corneal topography,refractive surgery,hyperopic laser in situ keratomileusis,hyperopia,Functional optical zone,corneal aberrations,hyperopic regression
更新于2025-09-11 14:15:04
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Polydopamine-Assisted Fabrication of Stable Silver Nanoparticles on Optical Fiber for Enhanced Plasmonic Sensing
摘要： We present a facile and effective method for fabrication of the localized surface plasmon resonance (LSPR) optical fiber sensor assisted by two polydopamine (PDA) layers with enhanced plasmonic sensing performance. The first PDA layer was self-polymerized onto the bare optical fiber to provide the catechol groups for the reduction from Ag+ to Ago through chelating and redox activity. As the reduction of Ag+ proceeds, Ag nanoparticles (NPs) were grown in-situ on the PDA layer with uniform distribution. The second PDA layer was applied to prevent Ag NPs from oxidating and achieve an improvement of LSPR signal. The PDA/Ag/PDA-based optical fiber sensor has an enhanced LSPR sensitivity of 961 nm/RIU and excellent oxidation resistance. The stable PDA/Ag/PDA-based LSPR sensor with high optical performance is very promising for future application in optical sensing field.
关键词： silver nanoparticles,in-situ growth,optical fiber,LSPR,polydopamine
更新于2025-09-11 14:15:04
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Recycling the GaN Waste from LED Industry by Pressurized Leaching Method
摘要： Background: Ductal carcinoma in situ with microinvasion (DCISM) represents ~1% of all breast cancer cases. Risk factors for lymph node (LN) metastasis and appropriate adjuvant therapy for DCISM are still widely debated. Methods: We retrieved DCISM data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results registry database (1998–2013). Chi-squared tests and logistic regression models were applied to investigate the potential risks of LN metastasis. Univariate and multivariate Cox proportional hazards regressions were performed to estimate the prognostic factors of DCISM. Survival outcomes were estimated using the Kaplan–Meier method. A 1:1 propensity score matching was used to minimize potential bias. Results: Overall, 6,219 patients with DCISM met our inclusion criteria. Younger age and higher grade disease were identified as risk factors for LN metastasis. In the multivariable analysis, LN metastasis and chemotherapy were prognostic factors for worse overall survival and breast cancer-specific survival. Furthermore, propensity score matching and subgroup analysis showed that chemotherapy may not be effective for DCISM patients. Conclusion: Younger patients with high-grade disease tend to have LN involved in DCISM. Adjuvant chemotherapy might not be necessary for patients with DCISM.
关键词： ductal carcinoma in situ with microinvasion,SEER database,breast cancer,lymphatic metastasis,adjuvant chemotherapy
更新于2025-09-11 14:15:04
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Development of a Cost-Effective Optical Sensor for Continuous Monitoring of Turbidity and Suspended Particulate Matter in Marine Environment
摘要： A cost-effective optical sensor for continuous in-situ monitoring of turbidity and suspended particulate matter concentration (SPM), with a production cost in raw materials less than 20 €, is presented for marine or fluvial applications. The sensor uses an infrared LED and three photodetectors with three different positions related to the light source—135o, 90o and 0o—resulting in three different types of light detection: backscattering, nephelometry and transmitted light, respectively. This design allows monitoring in any type of environment, offering a wide dynamic range and accuracy for low and high turbidity or SPM values. An ultraviolet emitter–receiver pair is also used to differentiate organic and inorganic matter through the differences in absorption at different wavelengths. The optical transducers are built in a watertight structure with a radial configuration where a printed circuit board with the electronic signal coupling is assembled. An in-lab calibration of the sensor was made to establish a relation between suspended particulate matter (SPM) or the turbidity (NTU) to the photodetectors’ electrical output value in Volts. Two different sizes of seashore sand were used (180 μm and 350 μm) to evaluate the particle size susceptibility. The sensor was tested in a fluvial environment to evaluate SPM change during sediment transport caused by rain, and a real test of 22 days continuous in-situ monitoring was realized to evaluate its performance in a tidal area. The monitoring results were analysed, showing the SPM change during tidal cycles as well as the influence of the external light and biofouling problems.
关键词： in-situ measurement,turbidity optical sensor,oceanography,suspended particulate matter
更新于2025-09-11 14:15:04
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European Microscopy Congress 2016: Proceedings || Quantitative measurement of doping and surface charge in a ZnO nanowire using in-situ biasing and off-axis electron holography
摘要： The measurement of doping and surface charge in a Zn2N3 nanowire using in-situ biasing and off-axis electron holography
关键词： surface charge,in-situ biasing,off-axis electron holography,Zn2N3 nanowire,doping
更新于2025-09-11 14:15:04
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Intraocular Lens Power Calculation in Eyes After Laser In Situ Keratomileusis or Photorefractive Keratectomy for Myopia
摘要： Intraocular power calculation is challenging for patients who have previously undergone corneal refractive surgery. The sources of prediction errors for these eyes are well known; however, the numerous formulas and methods available for calculating intraocular lens power in these cases are eloquent testimony to the absence of a definitive solution. This review discusses some of the available methods for improving the accuracy for predicting the refractive outcome for these patients. It focuses mainly on the methods available on the American Society of Cataract and Refractive Surgery (ASCRS) online calculator and provides some practical guidelines for cataract surgeons who encounter these challenging cases.
关键词： intraocular power calculation,in situ keratomileusis,photorefractive keratectomy
更新于2025-09-11 14:15:04
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In-Situ Observation of Coulomb Fission of Individual Plasmonic Nanoparticles
摘要： Reshaping plasmonic nanoparticles with laser pulses has been extensively researched as a tool for tuning their properties. However, in the absence of direct observations of the processes involved, important mechanistic details have remained elusive. Here, we present an in-situ electron microscopy study of one such process that involves Coulomb fission of plasmonic nanoparticles under femtosecond laser irradiation. We observe that gold nanoparticles encapsulated in a silica shell fission by emitting progeny droplets comprised of about 10-500 atoms, with ejection preferentially occurring along the laser polarization direction. Under continued irradiation, the emitted droplets coalesce into a second core within the silica shell, and the system evolves into a dual-core particle. Our findings are consistent with a mechanism in which electrons are preferentially emitted from the gold core along the laser polarization direction. The resulting anisotropic charge distribution in the silica shell then determines the direction in which progeny droplets are ejected. In addition to yielding insights into the mechanism of Coulomb fission in plasmonic nanoparticles, our experiments point towards a facile method for forming surfaces decorated with aligned dual-gold-core silica shell particles.
关键词： single-particle observation,gold-core silica shell particles,plasmonic nanoparticles,in-situ,nanoparticle reshaping,Coulomb fission,transmission electron microscopy
更新于2025-09-11 14:15:04
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Impact of In Situ Annealing Time on CdTe Polycrystalline Film and Device Performance
摘要： We studied the impact of in situ post-growth annealing process on cadmium telluride (CdTe) polycrystalline thin ?lm in this work. Samples of different annealing times have been characterized by x-ray diffraction (XRD) and a scanning electron microscope (SEM). The optoelectronic properties of CdTe ?lm were deeply studied with light I–V testing, external quantum ef?ciency (EQE) and photoluminescence (PL)/time-resolved photoluminescence (TRPL) measurements. It is found that the in situ post-growth annealing treatment has a great effect on cadmium sul?de (CdS)/CdTe intermixing as well as interface pinholes. Elementary correlations between annealing time, ?lm and junction morphology, carrier lifetime and device performance were investigated, and the annealing time turns out to be crucial to CdTe device performance. Solar cells with CdTe polycrystalline thin ?lm annealed in situ at 550(cid:2)C/550(cid:2)C for 10 min show the best performance. With the help of precisely controlled annealing time, better CdTe ?lm microstructure and morphology can be realized after in situ post-growth annealing.
关键词： CdTe solar cell,in situ annealing,TRPL
更新于2025-09-11 14:15:04