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We are developing a multi-wavelength laser for the two-step laser time-of-flight mass-spectrometer (L2MS). The L2MS is designed to detect hydrocarbons in organically-doped analog minerals, including cryogenic Ocean World-relevant ices and mixtures for future astrobiology missions.
InAs/InGaAs quantum dot mode-locked lasers are fabricated and characterized. The modal gain as the saturable absorber voltage (SAV) changes is investigated. The ground state lasing dominates at low SAV, and excited state transition emerges when SAV increases.
The ideality factor of a 2 μm InGaSb/AlGaAsSb quantum well laser is investigated. The total ideality factor comes mainly from the central p-n junction and two metal-semiconductor junctions. It decreases from 4.0 to 3.3 when the temperature is increased from 20 to 80 oC.
The visible light communications properties of a microLED-pumped inorganic perovskite quantum dot color converter are reported. Free-space data communications at 364 Mb/s, using solely the color-converted light as the data signal optical carrier, is demonstrated.
We have demonstrated 1200V and 3300V planar 4H-SiC MOSFET technology at our 6-inch foundry. 1200V MOSFETs demonstrate good avalanche ruggedness under single-and one million (1,000,000) repetitive unclamped inductive switching (UIS) pulse tests. 1200V MOSFETs can pass one hundred (100) 10 microsecond short-circuit events at 600V bus voltage, while 3300V MOSFETs can pass 5 microsecond short-circuit...
Exploitation and using of clean and renewable energy to improve the domestic energy structure is important for building smart city. Photovoltaic (PV) power generation is a good choose, and modules inspection is an important direction of PV power generation. The manual inspection is a common way but is not feasible for large-scale PV systems in practice due to low efficiency, high error rate and long...
A constant modulus algorithm-(CMA) based carrier frequency offset estimation method for coherent optical orthogonal frequency division multiplexing (CO-OFDM) system is proposed. Theoretical analysis and simulation results indicate that the frequency offset estimation range of the proposed algorithm can achieve [−5.9, +5.9] GHz, and the mean normalized estimation error can be kept under 0.001 even...
Understanding the surrounding environment including both still and moving objects is crucial to the design and optimization of intelligent vehicles. Knowledge about the vehicle environment could facilitate reliable detection of moving objects, especially irregular events (e.g., pedestrians crossing the road, vehicles making sudden lane changes,) for the purpose of avoiding collisions. Inspired by...
The design of high-speed electrical machines for flywheel systems should consider simultaneously electromagnetic, mechanical and thermal constraints. This paper presents the design of a 4-pole permanent magnet synchronous machine (PMSM) for a flywheel energy storage system, which is applied in an urban railway system. The machine has a maximum speed of 24000 min−1 and a rated power of 130 kW. A design...
By using a hybrid energy-harvesting mode, a novel self-powered wireless-sensing-node is developed for vibration-type distinguishable environment/event monitoring. The dual-stage piezoelectric vibration energy harvester has threshold-triggered electricity generating function. Such harvesters generate considerable power when the ambient vibration reaches the two preset conditions of acceleration and...
Deposition is found in many engineering processes, such as the asphaltene deposition in oil pipelines/wellbores, and biological and chemical foulings in pipes or heat exchangers. These deposition processes usually occur in a two-phase flow environment. This study develops a model for two-phase flow with deposition in vertical pipes. The model consists of three modules: Fluid Transport, Particle Transport,...
Radiomics, an emerging field of quantitative imaging, encompasses a broad class of analytical techniques. Recent literature have interrogated associations between quantitatively derived GLCM-based texture features and clinical/pathology information using machine learning algorithms in many cancer settings, but often fail to elucidate the predictive power of these features. Moreover, for many cancers...
We present single-intensity, energy- and angle-resolved photoelectron spectra from laser-driven gas-phase gold nanoparticles. Via single-shot, single particle analysis we sort the results according to particle's position in the laser focus avoiding focal volume averaging.
We demonstrate a 16×2.5 Gb/s (40 Gb/s aggregate) OFDM-CDMA PON for next-generation access applications. Four-channel error-free transmission over 25 km SMF shows 6 dB coding gain, with 0.1 dB dispersion and 0.9 dB crosstalk penalties.
The advent of several key enabling electro-optics technologies afford advanced, non-topographic remote sensing instruments for space. We will present progress on several new, space-based laser instruments that are being developed at NASA GSFC. Long Abstract: In the past 20+ years, NASA Goddard Space Flight Center (GSFC) has successfully developed and flown lidars for mapping of Mars, the Earth, Mercury...
We demonstrate a compact terahertz source based on a bimodal laser diode and a plasmonic photomixer, which generates 0.45 mW power at 1.62 THz and offers a broad radiation frequency tuning range of 0.15–3 THz.
We develop a sensitive collinear pump-probe technique to resolve small amplitude and phase modulations of laser pulses in hybrid PbS/CdS-quantum-dot-SiN waveguides. It shows that at high excitation rate biexciton creation governs the optical interaction.
The study explored how authentic leadership (AL) affected employees' work engagement (WE) both directly and through the mediating role of employees' Psychological Capital (PsyCap). Using a correlation research design, the authors collected valid responses from 304 employees across organizations through a paper survey in Beijing (China). The results showed both authentic leadership and PsyCap positively...
In this paper we demonstrate various configurations of THz microstrip antenna on GaN-on low resistivity silicon substrates (ρ < 40 Ω.cm). To reduce the losses caused by the substrate and to enhance the antenna performance, the driven patch is shielded by a ground plane and silicon nitride, with BCB as the inset layer between them. Second patch (elevated patch) is suspended in air using gold posts,...
The study aims to explore the influence of work-family conflicts on job involvement and organizational commitment, we also investigated the moderating effect of perceived supervisor support and the mediating effect of job satisfaction. 558 employees from small and middle size enterprise participated in our research, they came from 19 organizations including Eight different regions such as Beijing,...
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