Analysis of THz generation through the asymmetry of photoelectron angular distributions

Citation: Zhou, Z. Y., Wang, X., & Lin, C. D. (2017). Analysis of THz generation through the asymmetry of photoelectron angular distributions. Physical Review A, 95(3), 6. doi:10.1103/PhysRevA.95.033418We analyze the mechanism of THz generation in a gas medium with intense two-color infrared lasers pulses. The dependence of the amplitude of THz emission on the relative phase between the fundamental color (800 nm) and its second harmonic (400 nm) is shown to be identical to the residual current as well as to the asymmetry of the above-threshold-ionization (ATI) photoelectrons along the left versus the right side of the linear polarization axis of the laser, thus confirming the validity of the semiclassical photocurrent model for the THz emission. We further analyze the even vs odd angular momentum distributions of the ATI electrons. The degree of overlap between the even-parity dominant electrons and the odd-parity dominant electrons within each ATI peak determines the strength of the THz emission, thus favoring the model that THz is generated through free-free transitions in the laser field. A model is also provided to obtain the same phase dependence as the four-wave mixing model

Ticking terahertz wave generation in attoseconds

We perform a joint measurement of terahertz waves and high-order harmonics generated from noble atoms driven by a fundamental laser pulse and its second harmonic. By correlating their dependence on the phase-delay of the two pulses, we determine the generation of THz waves in tens of attoseconds precision. Compared with simulations and models, we find that the laser-assisted soft-collision of the electron wave packet with the atomic core plays a key role. It is demonstrated that the rescattering process, being indispensable in HHG processes, dominant THz wave generation as well but in a more elaborate way. The new finding might be helpful for the full characterization of the rescattering dynamics.Comment: 4 figure

Theory of Retrieving Orientation-Resolved Molecular Information using Time-Domain Rotational Coherence Spectroscopy

We provide a unified theoretical framework for recently emerging experiments that retrieve fixed-in-space molecular information through time-domain rotational coherence spectroscopy. Unlike a previous approach by Makhija et al. (V. Makhija, arXiv:1611.06476), our method can be applied to the retrieval of both real-valued (e.g., ionization yield) and complex-valued (e.g., induced dipole moment) molecular response information. It is also a direct retrieval method without using iterations. We also demonstrate that experimental parameters, such as the fluence of the aligning laser pulse and the rotational temperature of the molecular ensemble, can be quite accurately determined using a statistical method

Prevalence of polypharmacy and potentially inappropriate medication use in older lung cancer patients: A systematic review and meta-analysis

Objectives: In older lung cancer patients, polypharmacy and the use of potentially inappropriate medications (PIMs) are commonly reported, but no systematic review or meta-analysis has been carried out to ascertain the prevalence and risk variables in this group. This study aimed to identify the prevalence of polypharmacy, PIMs and associated risk variables in older lung cancer patients.Methods: We searched for articles from the beginning to February 2022 in PubMed, Embase, and Web of Science that related the use of PIMs and polypharmacy by older lung cancer patients (PROSPERO Code No: CRD42022311603). Meta-analysis was performed on observational studies describing the prevalence and correlation of polypharmacy or PIMs in older patients with lung cancer.Results: Of the 387 citations, 6 articles involving 16,890 patients were included in the final sample. In older lung cancer patients pooled by meta-analysis, 38% and 35% of PIMs and polypharmacy, respectively. The prevalence of PIMs was 43%, 49%, and 28%, respectively, according to the 2019 AGS Beers criteria, 2014 screening tool for older people’s prescriptions/screening tool for alerting to the proper therapy (STOPP/START criteria) criteria, and other criteria.Conclusion: This systematic review and meta-analysis demonstrated a high prevalence of polypharmacy and PIMs among older lung cancer patients. Therefore, it is essential to take rational interventions for older lung cancer patients to receive reasonable pharmacotherapy.Systematic Review Registration: [https://www.crd.york.ac.uk/PROSPERO/], identifier [CRD42022311603]

Theory of retrieving orientation-resolved molecular information using time-domain rotational coherence spectroscopy

Citation: Wang, X., Le, A.-T., Zhou, Z., Wei, H., & Lin, C. D. (2017). Theory of retrieving orientation-resolved molecular information using time-domain rotational coherence spectroscopy. Physical Review A, 96(2), 023424. https://doi.org/10.1103/PhysRevA.96.023424We provide a unified theoretical framework for recently emerging experiments that retrieve fixed-in-space molecular information through time-domain rotational coherence spectroscopy. Unlike a previous approach by Makhija et al. (V. Makhija et al., arXiv:1611.06476), our method can be applied to the retrieval of both real-valued (e.g., ionization yield) and complex-valued (e.g., induced dipole moment) molecular response information. It is also a direct retrieval method without using iterations. We also demonstrate that experimental parameters, such as the fluence of the aligning laser pulse and the rotational temperature of the molecular ensemble, can be quite accurately determined using a statistical method

New mitogenomes in deep-water endemic Cocculinida and Neomphalida shed light on lineage-specific gene orders in major gastropod clades

Gastropoda is the most speciose class in Mollusca, the second largest animal phylum, whose internal relationships remain largely unsettled, partly due to the insufficient data from key deep-water endemic lineages, such as the subclass Neomphaliones. Neomphaliones currently includes two orders: Cocculinida, best known from sunken wood habitats, and Neomphalida, best known from hydrothermal vents and often referred to as the ‘hot vent clade’. Phylogenetic controversy has also been observed in this subclass across different studies, requesting additional investigations. Here, we assembled nine new mitogenomes from two cocculinids and seven neomphalines and analyzed them with published gastropod mitogenomes, with a particular focus on Neomphaliones. The phylogenetic reconstruction of Gastropoda based on 13 mitochondrial protein-coding genes resulted in a topology largely congruent with previous reconstructions based on morphological characters. Furthermore, we recovered characteristic mitochondrial gene order arrangements of Cocculinida and Neomphalida compared to the hypothetical ancestral gastropod gene order, at a level similar to other subclass-level clades. Divergence time estimation showed that Cocculinida and Neomphalida diverged approximately 322.68 million years ago. In addition to characteristic gene order arrangements for the clade, cocculinid mitogenomes also exhibit some minor rearrangements even among congeners. Within Neomphalida, our tree adds support to monophyletic Peltospiridae and Neomphalidae, with unique gene arrangement recovered for each family. Our results offer new insights into the rearrangement of mitogenomes in Gastropoda, providing another clue to the evolutionary history of gastropods

All-small-molecule organic solar cells with over 14% efficiency by optimizing hierarchical morphologies

The high efficiency all-small-molecule organic solar cells (OSCs) normally require optimized morphology in their bulk heterojunction active layers. Herein, a small-molecule donor is designed and synthesized, and single-crystal structural analyses reveal its explicit molecular planarity and compact intermolecular packing. A promising narrow bandgap small-molecule with absorption edge of more than 930 nm along with our home-designed small molecule is selected as electron acceptors. To the best of our knowledge, the binary all-small-molecule OSCs achieve the highest efficiency of 14.34% by optimizing their hierarchical morphologies, in which the donor or acceptor rich domains with size up to ca. 70 nm, and the donor crystals of tens of nanometers, together with the donor-acceptor blending, are proved coexisting in the hierarchical large domain. All-small-molecule photovoltaic system shows its promising for high performance OSCs, and our study is likely to lead to insights in relations between bulk heterojunction structure and photovoltaic performance.Funding Agencies|Ministry of Science and Technology of ChinaMinistry of Science and Technology, China [2016YFA0200700, 2016YFF0203803]; National Natural Science Foundation of ChinaNational Natural Science Foundation of China [51961135103, 51973043, 21822503, 21534003, 21721002]; Beijing Nova ProgramBeijing Municipal Science &amp; Technology Commission [Z17110001117062]; Youth Innovation Promotion Association; K.C.Wong Education Foundation; Chinese Academy of SciencesChinese Academy of Sciences; Swedish Research Council VRSwedish Research Council [2018-06048, 2018-05484]</p

Multi-Step Ahead Short-Term Electricity Load Forecasting Using VMD-TCN and Error Correction Strategy

The electricity load forecasting plays a pivotal role in the operation of power utility companies precise forecasting and is crucial to mitigate the challenges of supply and demand in the smart grid. More recently, the hybrid models combining signal decomposition and artificial neural networks have received popularity due to their applicability to reduce the difficulty of prediction. However, the commonly used decomposition algorithms and recurrent neural network-based models still confront some dilemmas such as boundary effects, time consumption, etc. Therefore, a hybrid prediction model combining variational mode decomposition (VMD), a temporal convolutional network (TCN), and an error correction strategy is proposed. To address the difficulty in determining the decomposition number and penalty factor for VMD decomposition, the idea of weighted permutation entropy is introduced. The decomposition hyperparameters are optimized by using a comprehensive indicator that takes account of the complexity and amplitude of the subsequences. Besides, a temporal convolutional network is adopted to carry out feature extraction and load prediction for each subsequence, with the primary forecasting results obtained by combining the prediction of each TCN model. In order to further improve the accuracy of prediction for the model, an error correction strategy is applied according to the prediction error of the train set. The Global Energy Competition 2014 dataset is employed to demonstrate the effectiveness and practicality of the proposed hybrid model. The experimental results show that the prediction performance of the proposed hybrid model outperforms the contrast models. The accuracy achieves 0.274%, 0.326%, and 0.405 for 6-steps, 12-steps, and 24 steps ahead forecasting, respectively, in terms of the mean absolute percentage error

Soil Water Content Estimation Using High-Frequency Ground Penetrating Radar

The rapid high-precision and nondestructive determination of shallow soil water content (SWC) is of vital importance to precision agriculture and water resource management. However, the low-frequency ground penetrating radar (GPR) technology currently in use is insufficient for precisely determining the shallow SWC. Therefore, it is essential to develop and use a high-precision detection technology to determine SWC. In this paper, a laboratory study was conducted to evaluate the use of a high-frequency GPR antenna to determine the SWC of loamy sand, clay, and silty loam. We collected soil samples (0&#8722;20 cm) of six soil types of loamy sand, clay, and silty loam and used a high-frequency (2-GHz) GPR antenna to determine the SWC. In addition, we obtained GPR data and images as well as characteristic parameters of the electromagnetic spectrum and analyzed the quantitative relationship with SWC. The GPR reflection two-way travel times and the known depths of reflectors were used to calculate the average soil dielectric permittivities above the reflectors and establish a spatial relationship between the soil dielectric permittivity ( &#949; ) and SWC ( &#952; ), which was used to estimate the depth-averaged SWC. The results show that the SWC, which affects the attenuation of wave energy and the wave velocity of the GPR signal, is a dominant factor affecting the soil dielectric permittivity. In addition, the conductivity, magnetic soil, soil texture, soil organic matter, and soil temperature have substantial effects on the soil dielectric permittivity, which consequentially affects the prediction of SWC. The correlation coefficients R2 of the &#8220; &#952; &nbsp; ~ &nbsp; &#949; &#8221; cubic curve models, which were used to fit the relationships between the soil dielectric permittivity ( &#949; ) and SWC ( &#952; ), were greater than 0.89, and the root-mean-square errors were less than 2.9%, which demonstrate that high-frequency GPR technology can be applied to determine shallow SWC under variable hydrological conditions