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A cryogenic cylindrical ion trap velocity map imaging spectrometer
摘要： A cryogenic cylindrical ion trap velocity map imaging spectrometer has been developed to study photodissociation spectroscopy and dynamics of gaseous molecular ions and ionic complexes. A cylindrical ion trap made of oxygen-free copper is cryogenically cooled down to ～7 K by using a closed cycle helium refrigerator and is coupled to a velocity map imaging (VMI) spectrometer. The cold trap is used to cool down the internal temperature of mass selected ions and to reduce the velocity spread of ions after extraction from the trap. For CO2+ ions, a rotational temperature of ～12 K is estimated from the recorded [1 + 1] two-photon dissociation spectrum, and populations in spin-orbit excited X2Πg,1/2 and vibrationally excited states of CO2+ are found to be non-detectable, indicating an efficient internal cooling of the trapped ions. Based on the time-of-flight peak profile and the image of N3+ ions, the velocity spread of the ions extracted from the trap, both radially and axially, is interpreted as approximately ±25 m/s. An experimental image of fragmented Ar+ from 307 nm photodissociation of Ar2+ shows that, benefiting from the well-confined velocity spread of the cold Ar2+ ions, a VMI resolution of Δv/v ～ 2.2% has been obtained. The current instrument resolution is mainly limited by the residual radial speed spread of the parent ions after extraction from the trap.
关键词： cryogenic ion trap,velocity map imaging,ion cooling,photodissociation,spectroscopy
更新于2025-09-23 15:23:52
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Formation of Cobalt Impurity Microinclusions in Silicon Single Crystals
摘要： The structure and chemical composition of cobalt impurity microinclusions in silicon have been studied by electron probe microanalysis using n- and p-type Si?Co? samples prepared by diffusion doping and cooled at different rates after diffusion annealing. The cooling rate after diffusion annealing has been shown to have a significant effect on the structural parameters of the samples and the size of the forming impurity microinclusions. The size and shape of the impurity microinclusions determine their distribution over the bulk of the samples.
关键词： cobalt microinclusions,cobalt silicide,cooling rate,electron probe microanalysis
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Information and Communication Technology Robotics (ICT-ROBOT) - Busan (2018.9.6-2018.9.8)] 2018 International Conference on Information and Communication Technology Robotics (ICT-ROBOT) - Design of Air Cooling Housing for Image Sensors Using Additive Manufacturing Technology
摘要： Machine vision is widely used in industry for monitoring and inspection. In additive manufacturing technology (AM), it is especially important in that it can cover an entire 2-dimensional printed surface area instantly. Additionally, AM technologies can also be used to make a mechanical part for a machine vision system such as mount or illumination devices on a 3D printer. For the industrial 3D printer, the camera mount requires to have temperature control capabilities for the vision system. This research aims to develop a method to build a mount with cooling capability with AM technology. This paper introduces a 3D printed camera cooling housing and proposes a temperature feed-back control method based on the image sensor itself without adding a thermal sensor to increase the user friendliness and simplicity. In the demonstration, a camera cooling housing that was developed enabled a camera module to operate at 200°C in an industrial Fortus 400 (Stratasys, MN).
关键词： camera cooling system,3d printed heat exchanger,additive manufacturing,vision based thermal control
更新于2025-09-23 15:22:29
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Manipulation of nanomechanical resonator via shaking optical frequency
摘要： Cavity optomechanical system has made rapid advances in the past decades, which is mainly used to study the macroscopic quantum effects of the micromechanical resonators, such as the ground-state cooling of the mechanical resonator, mechanical squeezing, entanglement, macroscopic quantum superposition, etc. Owing to the unique advantages of optomechanical systems, numerous potential applications have been proposed, e.g., the ultrahigh precision metrology, exploring the quantum-classical boundary, and studying the weak signal transducer. The progress of the gravitational-wave detection is a great example for the application of optomechanics. In recent years, the periodically modulated optomechanical systems have attracted significant attention, which have been used to study various macroscopic quantum effects. However, in those modulation proposals, most of them focus on modulating the driven laser field, which results in the first-order moments of the system operators and the effective optomechanical coupling changing periodically to achieve and study some quantum effects. On the other hand, the frequency modulated quantum systems also exhibit a rich behavior and display nonequilibrium properties that are absent in their static counterparts, such as the phenomena of motional averaging and narrowing, Landau–Zener–Stückelberg–Majorana interference, and the formation of dressed states with the appearance of sidebands in the spectrum. However, in cavity optomechanical systems, the study of the influence coming from the frequency modulation is relatively rare to date. In this paper, we study an usual cavity optomechanical system where the frequency of the optical mode is shaken periodically. As we all know, the stability of optomechanical systems is closely related to the effective optomechanical coupling strength. For an excessively large coupling strength, the optomechanical systems are unstable and the studying is also meaningless. However, we find that the shaking optical mode can reduce the effective optomechanical coupling strength arbitrarily when the shaking frequency is much larger than the mechanical resonator frequency, and the deeply physical mechanism can be explained through the Raman-scattering and frequency domain pictures. The result indicates that it will be possible to study the steady quantum effects of optomechanical system even with strong coupling where the standard optomechanical systems without frequency modulation are always unstable. In order to verify the above analyses, we study the ground-state cooling of the mechanical resonator and the entanglement between the optical and mechanical modes in the conventional unstable region, and the results indicate that the final mean phonon number and entanglement not only can be achieved but also can be modulated by the optical shaking parameters. Our proposal provides a method to study the macroscopic quantum effects even in conventional unstable region.
关键词： micromechanical resonator cooling,entanglement,frequency modulation,optomechanics
更新于2025-09-23 15:22:29
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Localized Surface Plasmon Resonance Sensor Based at Metallic Sphere Dimer Particle
摘要： By the cooling holes in aero-engine turbine blade as the research object, this study focuses on two kinds of electrochemical machining(ECM) methods, which are mix gas added to the nonlinear electrolyte (NaNO3) and non-mixed gas. Mixed and non-mixed gas ECM experiments of turbine blade cooling holes were carried out respectively. The corresponding two-dimensional CAD model of cooling hole was constructed combined with the experimental data and theoretical analysis. Numerical simulation analysis was carried out of the flow field base on the above models by using the fluid dynamics analysis software FLUENT. The influence flow velocity and flow velocity distribution on the machining accuracy and efficiency of ECM were investigated in detail. The vortex zone distribution of gas-NaNO3 mixed phase flow field and single NaNO3 solution flow field was analyzed qualitatively. The simulation results indicated that the flow velocity in the machining gap with mixed gas was significantly higher than the velocity during ECM process for cooling holes. The electrolytic products and heat were washed away completely, the electrolyte can be updated in time. Fluid vortex zone distribution was improved obviously, the flow field distribution became more uniform after mixed gas in ECM process. The machining accuracy and efficiency for cooling holes making may be improved greatly with gas mixed in electrolyte NaNO3.
关键词： electrolytic machining,mixed gas,cooling hole,gas-liquid two-phase flow,CFD
更新于2025-09-23 15:22:29
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Nanoconfinement-Induced Giant Electrocaloric Effect in Ferroelectric Polymer Nanowire Array Integrated with Aluminum Oxide Membrane to Exhibit Record Cooling Power Density
摘要： The electrocaloric effect (ECE) offers a unique mechanism to realize environmentally friendly and highly efficient solid-state cooling that completely differs from the conventional vapor-compression refrigeration. Here a new class of hybrid films composed of ferroelectric polymer nanowire array and anodic aluminum oxide (AAO) membrane is reported, which displays pronounced ECE driven by relatively low electric fields. Under confinement and orientation of AAO channels on the crystallization of the polymer, the polymer nanowire array shows substantially enhanced ECE that is about three times that of the corresponding thin films. Simultaneously, the integrated AAO membrane forms thermally conducting channels for the polymer nanowires, enabling the efficient transfer of cooling energy and operation of the EC materials under high frequencies, which are unattainable based on the currently available EC structures. Consequently, the integrated polymer nanowire–AAO hybrid film exhibits the state-of-the-art cooling power density, outperforming the current ferroelectric polymers, ceramics, and composites. This work opens a new route for the development of scalable, high-performance EC materials for next-generation refrigeration.
关键词： electrocaloric effect,nanoconfinement,cooling power density,heat transfer,ferroelectric polymer
更新于2025-09-23 15:22:29
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Analysis of Sustainable Materials for Radiative Cooling Potential of Building Surfaces
摘要： The main goal of this paper is to explore the radiative cooling and solar heating potential of several materials for the built environment, based on their spectrally-selective properties. A material for solar heating, should have high spectral emissivity/absorptivity in the solar radiation band (within the wavelength range of 0.2–2 μm), and low emissivity/absorptivity at longer wavelengths. Radiative cooling applications require high spectral emissivity/absorptivity, within the atmospheric window band (8–13 μm), and a low emissivity/absorptivity in other bands. UV-Vis spectrophotometer and FTIR spectroscopy, are used to measure, the spectral absorption/emission spectra of six different types of materials. To evaluate the radiative cooling potential of the samples, the power of cooling is calculated. Heat transfer through most materials is not just a surface phenomenon, but it also needs a volumetric analysis. Therefore, a coupled radiation and conduction heat transfer analysis is used. Results are discussed for the selection of the best materials, for different applications on building surfaces.
关键词： sustainable materials,coupled radiation-conduction heat transfer,built environment,spectrally-selective surfaces,radiative cooling,roofs
更新于2025-09-23 15:22:29
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Deducing the Optimal Control Method for Electrochromic Triple Glazing through an Integrated Evaluation of Building Energy and Daylight Performance
摘要： Electrochromic glass is anticipated as the next generation of solar control glass for construction because it can control the transmittance of the glass itself. This study analyzed building energy and light environment performance by applying electrochromic glass in triple glazing in order to verify both the solar control characteristics of electrochromic glass and its high insulation performance. This paper evaluates the performance of the electrochromic glass developed by our research team in Korea in five control conditions of varying temperatures and solar radiation levels. By analyzing the cooling and heating load, lighting energy, Daylight Glare Index (DGI), and interior illuminance when applying the selected conditions to office buildings, this paper discerns the optimal control conditions for electrochromic glass. To do so, the optical characteristic data of the electrochromic glass was analyzed via an experiment, and the creation of triple glazing for construction was conducted. The performance of electrochromic glass was evaluated by analyzing hourly and yearly data for cooling, heating load, and lighting energy during a typical day in summer and winter. From this analysis, the control condition with an outstanding performance from an energy perspective was identified. The performance of the light environment was assessed, and the EDPI overall evaluation index was used to find the electrochromic glass’ optimum control conditions for integrating energy and light environment.
关键词： electrochromic glazing,EnergyPlus,optical properties,lighting energy,office building,heating and cooling loads,optimum control
更新于2025-09-23 15:22:29
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Photodetachment, electron cooling, and recombination, in a series of neat aliphatic room temperature ionic liquids
摘要： Transient absorption following photodetachment of a series of neat methyl-alkyl-pyrrolidinium bis(trifluoromethylsulfonyl)amides at 6.20 eV was measured with sub-picosecond time resolution in the visible and near-IR portions of the spectrum. This series spans the onset of structuring in the liquids in the form of polarity alternation. Excitation promotes the electron into a delocalized state with a very large reactive radius. Strong transient absorption is observed in the visible spectrum with a ～700 fs lifetime, and much weaker, long-lived absorption is observed in the near-IR spectrum. Absorption in the visible is shown to be consistent with the hole, and absorption in the near-IR is assigned to the free solvated electron. Yield of free electrons is estimated at ～4%, is insensitive to the size of the cation, and is determined in less than 1 ps. Solvation of free electrons depends strongly on the size of the cation and correlates well with the viscosity of the liquid. In addition to radiolytic stability of the aliphatic cations, ultrafast, efficient recombination of separated charge in NTf2? based ionic liquids following photo-excitation near the band-gap may prevent subsequent reactive damage associated with anions.
关键词： solvated electron,electron cooling,recombination,photodetachment,ionic liquids,transient absorption
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Conference on Imaging Systems and Techniques (IST) - Krakow (2018.10.16-2018.10.18)] 2018 IEEE International Conference on Imaging Systems and Techniques (IST) - Challenges for Electronic Displays in Sterile Medical Devices
摘要： Due to the ongoing digitalization, the demand for additional data is getting more into focus of users and industry. An approach for granting more data and enabling access to additional settings and parameters is since many decades the use of displays. Especially in medical industry, screens became an essential part of the daily work of doctors and medical staff. From patient monitors to blood sugar test devices, displays are present in all shapes and functions. However, these screens are still limited to be used in devices which can’t be sterilized. This is caused by the very harsh conditions of steam sterilizations, the most common type in Europe. Hereby, temperatures up to 135 degree Celsius and 3 bar pressure occur. This work is about the investigation of possible ways to insulate the displays to prevent them from permanent damages due to steam sterilizations and have a look on the possibility of cooling down the modules. For insulation an aerogel based insulation was tested with different LCD, LED and OLED displays. The aim of this research is enabling the use of displays in medical devices which need to be controlled manually and do not give back precise feedback. Therefore, the use of displays could increase safety for patients and usability for doctors significantly.
关键词： sterilization,healthcare,cooling,insulation,displays
更新于2025-09-23 15:22:29