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- 实验方案
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Single-shot Real-time Sub-nanosecond Electron Imaging Aided by Compressed Sensing: Analytical Modeling and Simulation
摘要： Bringing ultrafast (nanosecond and below) temporal resolution to transmission electron microscopy (TEM) has historically been challenging. Despite significant recent progress in this direction, it remains difficult to achieve sub-nanosecond temporal resolution with a single electron pulse, in real-time (i.e., duration in which the event occurs) imaging. To address this limitation, here, we propose a methodology that combines laser-assisted TEM with computational imaging methodologies based on compressed sensing (CS). In this technique, a two-dimensional (2D) transient event [i.e. (??, ??) frames that vary in time] is recorded through a CS paradigm, which consists of spatial encoding, temporal shearing via streaking, and spatiotemporal integration of an electron pulse. The 2D image generated on a camera is used to reconstruct the datacube of the ultrafast event, with two spatial and one temporal dimensions, via a CS-based image reconstruction algorithm. Using numerical simulation, we find that the reconstructed results are in good agreement with the ground truth, which demonstrates the applicability of CS-based computational imaging methodologies to laser-assisted TEM. Our proposed method, complementing the existing ultrafast stroboscopic and nanosecond single-shot techniques, opens up the possibility for single-shot, real-time, spatiotemporal imaging of irreversible structural phenomena with sub-nanosecond temporal resolution.
关键词： ultrafast imaging,compressed sensing,streak imaging,transmission electron microscopy
更新于2025-09-09 09:28:46
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Blind Transmitter IQ Imbalance Compensation in M-QAM Optical Coherent Systems
摘要： We investigate transmitter IQ imbalance compensation based on the blind adaptive source separation (BASS) method in a dual-polarization M-QAM optical coherent system. The robustness of the BASS method against the residual carrier frequency offset (CFO) is numerically investigated and compared to that of the Gram–Schmidt orthogonalization procedure (GSOP). We further validate experimentally the proposed method with 10 Gbaud optical 4-QAM and 16-QAM signals at 30° and 10° phase imbalance, respectively, with simulated impairments. More specifically, in the presence of 5 × 10?6 residual CFO (normalized to the sample rate), the optical signal-to-noise ratio penalty reduction of the BASS method compared to the GSOP method is 1 dB for 4-QAM at a bit error ratio (BER) of 2 × 10?3 and 2 dB for 16-QAM at a BER of 10?3. In contrast to the GSOP, which requires an independent block, the BASS method can be integrated into an equalizer, simplifying the operation and allowing parallel implementation.
关键词： M-QAM,IQ imbalance compensation,Digital signal processing,Optical coherent transmission
更新于2025-09-09 09:28:46
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A MODIFIED GYSEL POWER DIVIDER WITH ARBITRARY POWER DIVIDING RATIO
摘要： A modi?ed Gysel power divider with arbitrary power dividing ratio is proposed in this letter. The power dividing ratio of the proposed circuit is determined by both the electrical lengths and characteristic impedances of transmission lines. The proposed circuit is analyzed based on transmission line theory, and design equations are derived. For veri?cation, two prototypes operating at 2 GHz with power dividing ratios of 1 : 1 and 4 : 1 are designed, fabricated and measured, respectively. The measured results are in good agreements with the simulated ones.
关键词： characteristic impedances,electrical lengths,arbitrary power dividing ratio,transmission lines,Gysel power divider
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE 3rd Optoelectronics Global Conference (OGC) - Shenzhen, China (2018.9.4-2018.9.7)] 2018 IEEE 3rd Optoelectronics Global Conference (OGC) - Domestically Designed Integrated Silicon-Based Module for Coherent Optical Transmission Network
摘要： A line card with low power silicon-based module is demoed on current commercial network by Shanghai Telcom. This is China’s first domestically designed silicon-based module in coherent transmission systems. This module has an excellent performance. All key parameters passed the test requirements of Nx100Gbit/s optical wavelength division multiplexing systems and shows a more than 6-watt power consumption reduction.
关键词： silicon photonics,inhouse design,coherent optical transmission network
更新于2025-09-09 09:28:46
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Latent tracks in bulk yttrium-iron garnet crystals irradiated with low and high velocity krypton and xenon ions
摘要： Bulk yttrium-iron garnet (YIG) single crystals have been irradiated with swift Kr and Xe ions having energies from 0.4 to 22.8 MeV/u and electronic stopping powers from 8.9 to 28.9 keV/nm near the irradiated surface. Transmission electron microscopy (TEM) has been used for direct observation of non-overlapping amorphous latent tracks in the near surface region of the irradiated bulk YIG crystals. The amorphous track radii observed in this work have been compared with previously reported data from direct and indirect measurements. It was found that the thickness of the sample subjected to swift heavy ion irradiation does not significantly affect the resulting amorphous track size observed by TEM in YIG. The results also support previously observed consistency between direct TEM and indirect Rutherford backscattering in channelling mode (RBS/C) and Mossbauer spectroscopy (MS) methods for amorphous track evaluation in YIG when electronic stopping power is greater than ～13 keV/nm, which is sufficient to create cylindrical amorphous tracks by high velocity ions (E > 10 MeV/u). Indirect methods provide underestimated values compared to TEM when the electronic stopping power is below ～13 keV/nm, for which discrete amorphous tracks are supposed to be formed by high velocity ions.
关键词： Transmission electron microscopy,Latent tracks,Radiation damage,Yttrium-iron garnet,Swift heavy ions
更新于2025-09-09 09:28:46
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[IEEE 2018 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC) - Xuzhou (2018.7.21-2018.7.24)] 2018 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC) - A New Design for Spoof Surface Plasmon Polaritons Using Periodic Holes Etched on the Stripline
摘要： In this paper, a symmetrical ultrathin spoof surface plasmon polaritons (SSPPs) is realized based on the traditional coplanar waveguide (CPW), which can achieve multi-band high-efficiency transmission by employing the periodic holes etched on the middle stripline. Physical mechanism of the proposed SSPPs is explained by using the dispersion curves and electric field distributions. The measured results have a good agreement with the simulated ones, which indicate that the proposed SSPPs will be potentially very useful for microwave applications.
关键词： multi-band,spoof surface plasmon polaritons,high-efficiency transmission
更新于2025-09-09 09:28:46
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EXPRESS: Bulk Protein and Oil Prediction in Soybean Using Transmission Raman Spectroscopy: A Comparison of Approaches to Optimize Accuracy
摘要： Rapid measurements of protein and oil content are important for a variety of uses, from sorting of soybeans at the point of harvest to feedback during soybean meal production. In this study, our goal is to develop a simple protocol to permit rapid and robust quantitative prediction of soybean constituents using transmission Raman spectroscopy (TRS). To develop this approach, we systematically varied the various elements of the measurement process to provide a diverse test bed. First, we utilized an in-house-built benchtop TRS instrument such that suitable optical configurations could be rapidly deployed and analyzed for experimental data collection for individual soybean grains. Second, we also utilized three different soybean varieties with relatively low (33.97%), medium (36.98%), and high protein (41.23%) contents to test the development process. Third, samples from each variety were prepared using whole bean and three different sample treatments (i.e., ground bean, whole meal, and ground meal). In each case, we modeled the data obtained using partial least squares (PLS) regression and assessed spectral metric-based multiple linear regression (metric-MLR) approaches to build robust prediction models. The metric-MLR models showed lower root mean square errors (RMSEPs), and hence better prediction, compared to corresponding classical PLS regression models for both bulk protein and oil for all treatment types. Comparing different sample preparation approaches, a lower RMSEPs was observed for whole meal treatment and thus the metric-MLR modeling with ground meal treatment was considered to be optimal protocol for bulk protein and oil prediction in soybean, with RMSEP values of 1.15±0.04 (R2= 0.87) and 0.80±0.02 (R2= 0.87) for bulk protein and oil, respectively. These predictions were nearly two- to three-fold better (i.e., lower RMSEPs) than the corresponding NIR spectroscopy measurements (i.e., secondary gold standards in grain industry). For content prediction in whole soybean, incorporating physical attributes of individual grains in metric-MLR approach show up to 22% improvement in bulk protein and a relatively mild (up to ~ 5%) improvement in bulk oil prediction. The unique combination of metric-MLR modeling approach (which is rare in the field of grain analysis) and sample treatments resulted in improved prediction models, and using the physical attributes of individual grains is suggested as a novel measure for improving accuracy in prediction.
关键词： near-infrared spectroscopy,Soybean,NIR spectroscopy,MLR,transmission Raman spectroscopy,multiple liner regression,PLS regression
更新于2025-09-09 09:28:46
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Cloud removal based on dual tree complex wavelet transformation and improved atmosphere transmission
摘要： Clouds produce obstacles which hinder satellites from collecting clear ground information. Removing clouds from satellite images becomes a promising way to recover valuable information efficiently. It reduces the demands for weather and improves the image collecting flexibility. In this paper, a cloud removal algorithm from single images is studied. Firstly, the fundamental principle of the dual tree complex wavelet transformation (DTCWT) is introduced briefly. The scheme of dividing the clouds from the scenery and the background roughly according to their frequencies after the image is decomposed by DTCWT is discussed. Secondly, a new method to estimate the atmosphere transmission coefficient is designed after analyzing the atmosphere radiation model and the dark channel priori theory. Then, a cloud removal algorithm from single images is proposed by combining DTCWT and the improved atmosphere transmission. Its implement procedures are described completed. Image processing experiments are carried out and evaluated. The results prove the proposed algorithm is satisfactory and superior to algorithms based on the weighted wavelet coefficients and the dark channel prior.
关键词： atmosphere transmission,DTCWT,dark channel prior,Cloud removal
更新于2025-09-09 09:28:46
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Manipulating and monitoring nanoparticles in micellar thin film superstructures
摘要： Understanding the dynamics of discrete self-assembled structures under influence of external triggers is of interest to harvest the potential of nano- and mesoscale materials. In particular, controlling the hierarchical organization of (macro)molecular and nanoparticle building blocks in monolayer superstructures is of paramount importance for tuning properties and characteristics. Here we show how the electron beam in cryo-transmission electron microscopy can be exploited to induce and follow local migration of building blocks and global migration of micellar aggregates inside micrometer-sized superstructures. We employ stroboscopic exposure to heat up and convert the vitrified superstructure into a liquid-like thin film under cryogenic conditions, resulting in controlled evaporation of water that finally leads to rupture of the micelle-containing superstructure. Micelle-embedded nanoparticles prove a powerful tool to study the complex hierarchically built-up superstructures, and to visualize both global movement of individual dendrimicelles and local migration of nanoparticles inside the micellar core during the exposure series.
关键词： cryo-transmission electron microscopy,self-assembly,nanoparticles,hierarchical organization,micellar thin film
更新于2025-09-09 09:28:46
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Monitoring the Antiplatelet Effect of Cilostazol with Light Transmission Aggregometer: Two Cases of Possible Cilostazol Resistance
摘要： Background: Coronary artery disease is an important cause of death in adults and stent insertion is one of the treatment modalities. The most severe adverse effect of a stent insertion is the formation of a thrombus; therefore, antiplatelet agents are used. The addition of cilostazol to low-dose aspirin and clopidogrel results in a better antiplatelet effect. However, laboratory tests to monitor the effect of cilostazol are insufficient. Methods: We tested the inhibitory effect of cilostazol using maximal platelet aggregation in 20 healthy volunteers. Conditions for incubation and concentrations of cilostazol and prostaglandin E1 (PGE1) were established and aggregation was induced by 5′-adenosine diphosphate (ADP) and measured with light transmission aggregometry (LTA). Blood samples were incubated with 1 μM and 2 μM cilostazol for 10 minutes at room temperature, and 80 nM PGE1 was added and incubated for an additional 10 minutes. Aggregation was induced by ADP and reactivity was evaluated. Results: The average maximum aggregation (MA) was 58.1% at 1 μM cilostazol and 22.0% when PGE1 was added. The average MA was 42.8% when cilostazol concentration was increased to 2 μM and 21.2% when PGE1 was added. Average inhibition of aggregation at 1 μM cilostazol was not statistically significant (P=0.085), but was significant (P=0.004) at 2 μM cilostazol. Aggregation was not inhibited even with 2 μM cilostazol and PGE1 in 2 volunteers, which suggests possible resistance to cilostazol. Conclusions: We designed a method to monitor the effect of cilostazol using in vitro incubation with PGE1.
关键词： Antiplatelet,Light transmission aggregometry,Cilostazol
更新于2025-09-09 09:28:46