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Highly efficient green upconversion luminescence of ZnMoO4:Yb3+/Er3+/Li+ for accurate temperature sensing
摘要： Upconversion luminescence and optical temperature sensing properties of Yb3+/Er3+/Li+ tri-doped ZnMoO4 phosphors were investigated. It has been demonstrated that Li+ doping affected not only the local symmetry of Yb3+ and Er3+ but also the distribution of them in the host lattice. As a result, the significantly improved green upconversion luminescence was obtained when excited at 980 nm. The pumping power dependent photo-thermal behavior was used to evaluate the reliability of upconversion temperature sensing. An accurate temperature scale was established by eliminating the impact of thermal effect, and the sensing ability was evaluated via a comparison with the results reported in literatures.
关键词： Li+ doping,Upconversion luminescence,Thermal effect,Temperature sensing,ZnMoO4
更新于2025-09-23 15:23:52
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[IEEE 2019 20th International Conference on Electronic Packaging Technology(ICEPT) - Hong Kong, China (2019.8.12-2019.8.15)] 2019 20th International Conference on Electronic Packaging Technology(ICEPT) - Effects of Cracks on Interfacial Thermal Properties of LED Packages by Entropy Generation
摘要： Entropy generation is a kind of available energy loss. Evolution of thermodynamic entropy during accelerated test of die attach in LED is studied with transient analysis. The existing models on the study of heat transfer in the solder layer, mainly including the effect of voids on the mechanical properties and the heat transfer performance. However, there are few investigations that relating the second law of thermodynamics to the voids in the DA layer, transient heat distribution is less considered. In this work, based on the temperature distribution, the convection entropy rate of the chip to the ambient and the conduction entropy of the DA layer are studied. The results show that, as the length of the crack increases, both the convection entropy rate and the conduction entropy increase. Particularly, when the crack length was increased from 30% to 40%, the normalized conduction entropy of the DA layer showed a sharp increase, which indicates that the large crack (more than 30%) will pose a serious challenge to the quality of the LED packaging.
关键词： thermal effect,DA layer,cracking,transient,entropy generation
更新于2025-09-23 15:21:01
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Optical Trapping of Nanoparticles Using All-Silicon Nanoantennas
摘要： The ability to optically trap nanoscale particles in a reliable and noninvasive manner is emerging as an important capability for nanoscience. Different techniques have been introduced, including plasmonic nanostructures. Nano-optical tweezers based on plasmonics face the problem of Joule heating however due to high losses in metals. Here we experimentally demonstrate the optical trapping and transport of nanoparticles using a non-plasmonic approach, namely a silicon nanoantenna. We trap polystyrene nanoparticles with diameters of 20 and 100 nm, and use fluorescence microscopy to track their positions as a function of time. We show that multiple nanoparticles can be trapped simultaneously with a single nanoantenna. We show that the infrared trapping laser beam also produces fluorescent emission from trapped nanoparticles via two-photon excitation. We present simulations of the nanoantenna that predict enhanced optical forces with insignificant heat generation. Our work demonstrates that silicon nanoantennas enable nanoparticles to be optically trapped without deleterious thermal heating effects.
关键词： Optical trapping,silicon nanoantenna,thermal effect,optical force,nanoparticle
更新于2025-09-23 15:21:01
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Experimental investigations on thermal effects of a long-pulse alexandrite laser on blood vessels and its comparison with pulsed dye and Nd:YAG lasers
摘要： Laser has been widely used in the treatment of vascular skin diseases, such as port wine stain, due to the effect of selective photothermolysis in laser on biological tissue. The 755 nm alexandrite laser was expected to achieve better curative effect than the commonly used 585 or 595 nm pulsed dye laser (PDL) because of its deeper tissue penetration. In this study, the dorsal chamber model and microscopic visualization system were used to observe morphology changes on 42 blood vessels before and after irradiation with the 755 nm laser. Results showed that thermal effects of blood vessels intensified with the increase in energy, and high energy was required to produce the same thermal effect as the extension of pulse width. Different from 595 and 1064 nm lasers, partial vessel contraction was dominant thermal effect caused by the 755 nm laser. The bleeding injury rate and thermal effect of the 755 nm laser were between those of 595 nm PDL and 1064 nm Nd:YAG laser. The simulation results proved that 595 nm PDLs were effective for small and shallow target blood vessels. The 755 nm alexandrite lasers were effective in the treatment of hypertrophic and resistant blood vessels to PDL in the skin with low or moderate melanin concentration. The 1064 nm Nd:YAG laser was effective in the treatment of deeply buried and enlarged target blood vessels in the skin with high melanin concentration. The simulation results were supported by published clinical observations.
关键词： Laser therapy,Port wine stain,Vascular thermal effect,755 nm lasers
更新于2025-09-23 15:19:57
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Temperature changes during laser lithotripsy with Ho:YAG laser and novel Tm-fiber laser: a comparative in-vitro study
摘要： Aim The aim of this study was to compare the thermal effects of Ho:YAG and Tm-fiber lasers during lithotripsy in an in-vitro model via real-time temperature measurement. Methods We compared a Ho:YAG laser (pav up to 100 W, Lumenis, Yokneam, Israel) and a superpulse Tm-fiber laser (SP TFL, pav up to 40 W, NTO IRE-Polus, Fryazino, Russia), both equipped with 200 μm bare-ended fibers. The following settings were used: 0.2 J, 40 Hz (nominal pav 8 W). Power meter FieldMaxII-TO (Coherent, Santa Clara, CA, USA) was used to verify output laser power (pav). Each laser was fired for 60 s in two setups: (1) thermos-insulated (quasi-adiabatic) cuvette; (2) actively irrigated setup with precise flow control (irrigation rates 0, 10, 35 mL/min). Results Power measurements performed before the test revealed a 10% power drop in Ho:YAG (up to 7.2 ± 0.1 W) and 6.25% power drop in SP TFL (up to 7.5 ± 0.1). At the second step of our experiment, irrigation reduced the respective temperatures in the same manner for both lasers (e.g., at 35 mL/s SP TFL ? 1.9 °C; for Ho:YAG laser ? 2.8 °C at 60 s). Conclusion SP TFL and Ho:YAG lasers are not different in terms of volume-averaged temperature increase when the same settings are used in both lasers. Local temperature rises may fluctuate to some degree and differ for the two lasers due to varying jet streaming caused by non-uniform heating of the aqueous medium by laser light.
关键词： Ho:YAG laser,Laser lithotripsy,Thermal effect,Thulium fiber laser,In-vitro
更新于2025-09-23 15:19:57
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Histological Effects of an Innovative 445 Nm Blue Laser During Oral Soft Tissue Biopsy
摘要： Continuously evolving laser devices can be used in various fields; they are an alternative to the traditional cold blade surgery to perform biopsies of oral soft tissues. The aspect focused on in this paper is the possibility to use the 445 nm diode laser (Eltech K-Laser srl, Treviso, Italy) in complete safety, by evaluating its thermal effects during microscopy. A histological evaluation of the alteration of the peri-incisional edges on 10 samples was realized. All excisional biopsies were related to clinically unsuspected lesions and performed by the same expert operator. The surgical procedure was performed with the same laser parameters and the same pathologist evaluated the thermal effect on the samples. An average value of the detected tissue alteration was calculated; the average damage of the epithelium was 650.93 μm, while in the connective tissue it was 468.07 μm. In all the cases a clear diagnosis was possible, and no clinical complications were observed; so, the 445 nm diode laser proved to be a device that can be safely used for biopsies of clinically unsuspicious lesions. Due to the small number of cases, this in vivo preliminary experience needs to be extended.
关键词： thermal effect,oral biopsy,blue laser 445 nm
更新于2025-09-23 15:19:57
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Re: Safety of a Novel Thulium Fibre Laser for Lithotripsy: An In Vitro Study on the Thermal Effect and Its Impact Factor
摘要： Peng et al present for the first time data regarding the temperature rise following activation of a thulium fibre laser (TFL) for lithotripsy. In an in vitro setting, the thermal effect of TFL was evaluated at different laser power settings and irrigation rates with the safety temperature threshold set to 43°C. Without irrigation, laser power >10 W caused an increase in temperature above this safety threshold. When low-flow irrigation (15 ml/min) was used, only laser power of 30 W exceeded the safety threshold. Higher flow rates prevented a rise in temperature above the threshold for any of the laser settings tested.
关键词： Thermal Effect,Thulium Fibre Laser,Lithotripsy,Safety Temperature Threshold
更新于2025-09-19 17:13:59
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Electricity-triggered Self-healing of Conductive and Thermostable Vitrimer Enabled by Paving Aligned Carbon Nanotubes
摘要： Electrically conducting films are important for the development of modern electronics. However, most of these conducting films become susceptible to structure fractures under the complex deformations or accidental damages, causing the devices to fail to work. Inspired by the self-healing capability of creatures, we developed a self-healing, thermostable, and electrically conducting film that can be healed by electricity by paving aligned carbon nanotube (CNT) sheets onto the surface of liquid-crystal elastomer composite films. The aligned CNT sheets make the composites conductive, so the composites can be healed not only by light, but also by electricity after breaking. The scratches on the self-healing film can be healed easily under a voltage of 1.18 V/mm because of the electro-thermal effect of aligned CNT sheets. The healed film has almost the same mechanical properties compared to the pristine sample. The electrical and mechanical self-heal of the film is derived from the electrical reconnection of carbon nanotubes and transesterification-induced topology change of the network, respectively. We further demonstrated soft actuators and high-performance supercapacitors based on the prepared self-healing conducting films. This method for preparing self-healing conducting films enables the development of self-healing electronics.
关键词： electro-thermal effect,soft actuator,self-healing conducting film,flexible electronics,carbon nanotube sheet
更新于2025-09-19 17:13:59
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Ex vivo histological analysis of the thermal effects created by a 445-nm diode laser in oral soft tissue biopsy
摘要： Objective The aim of this study was to evaluate, ex vivo, the histological effects of 445-nm diode laser (Eltech K-Laser srl, Treviso, Italy), during an oral soft tissue biopsy. Materials and methods Thirty samples from pig cadaver tongues were obtained, through five laser settings, in continuous and pulsed wave (CW and PW). Samples were divided into six groups of five pieces each. A control specimen was taken by a scalpel. All samples were examined with an optical microscope by a blinded pathologist. Thermal effects on epithelium and connective tissues were measured with LAS 4.8 software. Finally, a statistical evaluation was made using GraphPadPrism 7.0 software. Results All specimens, except one, showed a damage lower than 1 mm. Readability was always optimal; there was a different thermal effect between epithelial and connective tissue and in CW and PW samples, confirmed by statistical analysis too. Conclusions A 445-nm diode laser creates a minimum thermal effect, that has no implications in the histological evaluation of benign lesions. In suspicious lesions, a safety margin of 1 mm, compared with a scalpel, is preferable. Clinical relevance A 445-nm diode laser has excellent surgical properties and can manage many arduous clinical cases, such as vascularized lesions. In the excision of suspected lesions, it is necessary to compare, case by case, clinical advantages to possible histological implications.
关键词： Blue laser 445 nm,Oral biopsy,Thermal effect
更新于2025-09-16 10:30:52
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Nanoplasmonics - Fundamentals and Applications || Optical Absorption and Thermal Effects of Plasmonic Nanostructures
摘要： With resonant light illumination, metallic nanostructures convert electromagnetic fields’ energy into heat because of optical absorption associated with plasmonic resonance. The optical absorption triggers a heat generation process that involves not only the absorption of photon energy but also heat transfer from the nanostructures to the surrounding medium. In this chapter, we study enhanced optical absorption of plasmonic nanostructures. Moreover, thermal effects induced by optical absorption and heat transfer between nanostructures are analyzed.
关键词： nanoparticle,absorption,thermal effect,optical trapping,plasmonics
更新于2025-09-16 10:30:52