bluuebunny/crossref_metadata_2025 huggingface dataset:
Aggregation of discoidal particles due to depletion interaction
Authors: Calero C. , Díaz-Morata M. , Pagonabarraga I.
Published: August 2021

Depletion interactions between colloids of discoidal shape can induce their self-assembly into columnar aggregates. This is an effect of entropic origin with important implications in a range of colloidal systems, particularly in the clustering of erythrocytes that determine the rheological properties of blood. Here, we investigate the equilibrium state reached by discoidal colloids in a solution of smaller depletant particles. We develop a thermodynamic model of depletion-induced aggregation based on self-assembly theory and solve it analytically. We test the validity of the model by using Langevin simulations of a system of discs and depletant particles in which the depletion interaction emerges naturally. In addition, we consider the effect of an attractive interaction between depletant and discoidal particles, which we show induces a re-entrant dependence of aggregation with temperature.
A double-layer wideband radial-line waveguide power divider/combiner for high-power microwave application
Authors: Xu Liang , Yuan Cheng-wei , Zhang Qiang , Sun Yun-fei , Liu Jin-liang
Published: August 2021

A compact double-layer wideband 1:60 power divider/combiner based on a radial-line waveguide is designed and investigated for high-power microwave (HPM) applications. Compared with other HPM radial-line power dividers, the proposed power divider is smaller and more compact. The power divider is miniaturized by the double-layer method, and the wideband characteristic is realized by a specially designed wavy disk. Moreover, it can divide the microwave energy into 60 output ports equally by symmetrical design. As for simulation, in the range of 1.64–3.6 GHz, the voltage standing-wave ratio is below 2 (the relative bandwidth is 76%) and the return loss reaches −44 dB at 2.1 GHz. Additionally, a prototype is fabricated and the wideband performance from 1.6 to 2.6 GHz is verified by an existing wideband antenna array. Furthermore, filled with SF6 (0.3 MPa), the theoretical power handling capacity is more than 200 MW and the device works steadily in HPM tests under the condition of 140 MW. To sum up, the compact power divider/combiner has important application potentials in HPM fields.
Small-polaron-induced infrared opacification in rutile TiO2
Authors: González de Arrieta I. , González-Fernández L. , Echániz T. , del Campo L. , De Sousa Meneses D. , López G. A.
Published: August 2021

The infrared emittance of single-crystal rutile TiO2 has been measured from room temperature to 2000 K in dry air for two polarization states. A very strong thermally induced opacification phenomenon has been found, with the sample being completely opaque in the near-infrared range several hundred K before its melting point. A large contribution from small-polaron hopping conduction can explain this anomalous degree of opacification, much stronger than similar phenomena present in other octahedrally coordinated oxide materials. These quasiparticles manifest in the high-temperature optical conductivity as a thermally activated contribution, with an activation energy close to that of DC conductivity. The small-polaron nature of this phenomenon is strengthened by the observation of broad near-infrared bands.
Manipulating heat transport of photoluminescent composites in LEDs/LDs
Authors: Xie Bin , Hu Run , Luo Xiaobing
Published: August 2021

Photoluminescent composites play a critical role of light converters in light-emitting devices, especially in high-power light-emitting diodes and laser diodes, while the nonradiative Stokes loss in photoluminescent particles not only generates thermal phonons with temperature rise but also degrades their photonic/electronic properties. Moreover, these micro/nanoscale heat sources are usually dispersed in a low-thermal-conductivity polymer matrix, which makes it tough to dissipate heat out efficiently, resulting in significant thermal quenching. Reinforcing the heat dissipation of photoluminescent composites is considerably important and challenging since their optical performance will be easily damaged by the thermal reinforcement processes. In this Perspective, we briefly introduce the heat generation and transportation mechanisms in photoluminescent composites and then emphasize the recent progresses in heat manipulation of photoluminescent composites. Finally, we outline some challenges and possible solutions for addressing the thermal management of photoluminescent composites as well as some future directions in this field.
How coronavirus survives for hours in aerosols
Authors: Chatterjee Sanghamitro , Murallidharan Janani Srree , Agrawal Amit , Bhardwaj Rajneesh
Published: August 2021

COVID (CoronaVirus Disease)-19, caused by severe acute respiratory syndrome-CoronaVirus-2 (SARS-CoV-2) virus, predominantly transmits via airborne route, as highlighted by recent studies. Furthermore, recently published titer measurements of SARS-CoV-2 in aerosols have disclosed that the coronavirus can survive for hours. A consolidated knowledge on the physical mechanism and governing rules behind the significantly long survival of coronavirus in aerosols is lacking, which is the subject of the present investigation. We model the evaporation of aerosolized droplets of diameter ≤5 μm. The conventional diffusion-limited evaporation is not valid to model the evaporation of small size (μm–nm) droplets since it predicts drying time on the order of milliseconds. Also, the sedimentation timescale of desiccated droplets is on the order of days and overpredicts the virus survival time; hence, it does not corroborate with the above-mentioned titer-decay timescale. We attribute the virus survival timescale to the fact that the drying of small (∼μm–nm) droplets is governed, in principle, by the excess internal pressure within the droplet, which stems from the disjoining pressure due to the cohesive intermolecular interaction between the liquid molecules and the Laplace-pressure. The model predictions for the temporal reduction in the aerosolized droplet number density agree well with the temporal decay of virus titer. The findings, therefore, provide insight on the survival of coronavirus in aerosols, which is particularly important to mitigate the spread of COVID-19 from indoors.
ZnO/graphene heterostructure nanohybrids for optoelectronics and sensors
Authors: Wu Judy , Gong Maogang
Published: August 2021

The discovery of graphene has prompted an intensive exploration and research of heterostructure nanohybrids that integrate functionalities of semiconductor nanostructures with graphene's high charge carrier mobility, extraordinary mechanical strength, and flexibility for various applications. Among others, zinc oxide (ZnO) presents a promising candidate due to its unique physical properties including direct bandgap in ultraviolet spectrum, ferroelectricity, and hence piezoelectricity, moderate Debye length for electron depletion effect in ZnO nanostructures (quantum dots, nanowire, nanoparticles), etc. For ZnO/graphene heterostructure nanohybrids, the low thermal budget for growth of crystalline ZnO makes it possible for direct deposition of ZnO on graphene with controlled morphology and interface, enabling a large spectrum of devices including photodetectors, gas sensors, strain sensors, and self-power devices. In this Perspective, we discuss the recent progress made in ZnO/graphene heterostructure nanohybrids through understanding and engineering the ZnO/graphene interface to realize high performance. An overview of the remaining issues and future perspectives toward commercialization of the ZnO/graphene heterostructure nanohybrids will also be provided.
Vertical Josephson field-effect transistors based on black phosphorus
Authors: Xu Zuyu , Chen Wei , Huang Junwei , Tian Wanghao , Chen Shixian , Yue Wencheng , Chi Tianyuan , Lyu Yang-Yang , Sun Hancong , Wang Yong-Lei , Sun Guozhu , Chen Jian , Jin Biaobing , Li Song-Lin , Yuan Hongtao , Li Jun , Koelle Dieter , Kleiner Reinhold , Wang Huabing , Wu Peiheng
Published: August 2021

The gate-tunable Josephson junction, generally achieved in planar Josephson field-effect transistors (JoFETs), is a key element for the applications of superconducting devices. At present, the performance of these systems with planar JoFETs is often impeded by the large channel length, which, at best, lies in the range of tens of nanometers. In contrast, the channel length in vertical junctions can be easily scaled down to nano-scale to realize the strong Josephson coupling. However, the vertical junctions are believed to be insensitive to the field-effect due to the atomic screening of electric fields in metals. Here, we report on a novel realization of few-layer black phosphorus (BP)-based vertical JoFETs using an electric-double-layer configuration. In transport experiments, using junctions of different shape, superconducting quantum interference device-like magnetic diffraction patterns of the junction critical current and anomalous Shapiro steps on current voltage characteristics are observed, strongly indicating that the critical current density in the junctions is highly inhomogeneous and peaked at the edges or even near the junction corners. The electric-field tunability of the Josephson coupling could be attributed to the edge- or corner-dominated supercurrent density profile combining with the carrier diffusivity in the few-layer BP. The ability to control the vertical Josephson coupling provides us with new opportunities to study high-performance and high-temperature superconducting Josephson field-effect transistors operating on an atomic-scale channel length.
Correlates of sexually transmitted infection knowledge among late adolescents
Authors: Lederer Alyssa M. , Vertacnik Amy L.
Published: August 2021

Background Accurate knowledge about sexually transmitted infections (STIs) is imperative for young people’s development and sexual health outcomes, but STI knowledge has been found to be inadequate among youth. Little is known about the factors that are associated with STI knowledge. This study therefore comprehensively assessed correlates of STI knowledge among late adolescents. Methods: Undergraduate students (n = 419) at a large public Midwestern university completed an online survey that assessed general STI knowledge using an established modified scale, demographics, sexual health and behavioural factors, and sources of STI information. Exploratory bivariate analyses were first conducted followed by a multiple linear regression examining the correlates initially identified as significantly and strongly associated with STI knowledge. Results: Although many factors were significantly correlated with STI knowledge, gender, nationality, sexual identity, STI testing history, knowing someone diagnosed with an STI, prior school-based STI education, and receiving STI information from a healthcare provider were most strongly associated (P < 0.001 with medium or large effect sizes). All but prior school-based STI education were predictive of STI knowledge score (P = 0.103), with nationality (β = 0.172, P = 0.003) and gender (β = 0.147, P = 0.002) being the strongest predictors. Conclusions: Late adolescents’ STI knowledge was universally low, but disparities existed and were related to a variety of characteristics. These findings expand the current literature on young people’s STI knowledge and provide needed information to prioritise populations and methods for educational interventions in order to enhance STI knowledge among youth.
When Qing Law Encountered British Anthropology
Authors: Liu Rui
Published: August 2021

This article conducts a textual and reception analysis of George Jamieson’s translation of Qing marriage law with
the aim of probing a translational encounter between traditional Chinese law and British anthropology. Approaching a Qing clause
against marriage between persons of the same family name as an object of anthropological study, Jamieson annotated his rendition
with rich paratexts to orient it under the concept of exogamy. After reflecting upon predecessors’ theories, he advanced his own
by restructuring existing anthropological constructs. Taking his translation as a knowledge source, Jamieson further highlighted
the existence of an endogamous limit upon the exogamy rule; this observation was absorbed by Henry Maine to strengthen his
argument that exogamy and endogamy were not oppositional in agnatic societies. As revealed in Jamieson’s interaction with British
anthropologists, he proved himself more than a translator of Qing marriage law but also a contributor to nineteenth-century
British anthropology.
Effect of laser temporal intensity skew on enhancing pair production in laser—electron-beam collisions
Authors: Bradley L E , Streeter M J V , Murphy C D , Arran C , Blackburn T G , Galletti M , Mangles S P D , Ridgers C P
Published: August 2021

Recent high-intensity laser experiments (Cole et al 2018 Phys. Rev. X
8 011020; Poder et al 2018 Phys. Rev. X
8 031004) have shown evidence of strong radiation reaction in the quantum regime. Experimental evidence of quantum effects on radiation reaction and electron–positron pair cascades has, however, proven challenging to obtain and crucially depends on maximising the quantum parameter of the electron (defined as the ratio of the electric field it feels in its rest frame to the Schwinger field). The quantum parameter can be suppressed as the electrons lose energy by radiation reaction as they traverse the initial rise in the laser intensity. As a result the shape of the intensity temporal envelope becomes important in enhancing quantum radiation reaction effects and pair cascades. Here we show that a realistic laser pulse with a faster rise time on the leading edge, achieved by skewing the temporal envelope, results in curtailing of pair yields as the peak power is reduced. We find a reduction in pair yields by orders of magnitude in contrast to only small reductions reported previously in large-scale particle-in-cell code simulations (Hojbota et al 2018 Plasma Phys. Control. Fusion
60 064004). Maximum pairs per electron are found in colliding 1.5 GeV electrons with a laser wakefield produced envelope 7.90 × 10−2 followed by a short 50 fs Gaussian envelope, 1.90 × 10−2, while it is reduced to 8.90 × 10−5, a factor of 100, for an asymmetric envelope.
Closed-loop automated reaching apparatus (CLARA) for interrogating complex motor behaviors
Authors: Bowles S , Williamson W R , Nettles D , Hickman J , Welle C G
Published: August 2021

Objective. Closed-loop neuromodulation technology is a rapidly expanding category of therapeutics for a broad range of indications. Development of these innovative neurological devices requires high-throughput systems for closed-loop stimulation of model organisms, while monitoring physiological signals and complex, naturalistic behaviors. To address this need, we developed CLARA, a closed-loop automated reaching apparatus. Approach. Using breakthroughs in computer vision, CLARA integrates fully-automated, markerless kinematic tracking of multiple features to classify animal behavior and precisely deliver neural stimulation based on behavioral outcomes. CLARA is compatible with advanced neurophysiological tools, enabling the testing of neurostimulation devices and identification of novel neurological biomarkers. Results. The CLARA system tracks unconstrained skilled reach behavior in 3D at 150 Hz without physical markers. The system fully automates trial initiation and pellet delivery and is capable of accurately delivering stimulation in response to trial outcome with short latency. Kinematic data from the CLARA system provided novel insights into the dynamics of reach consistency over the course of learning, suggesting that learning selectively improves reach failures but does not alter the kinematics of successful reaches. Additionally, using the closed-loop capabilities of CLARA, we demonstrate that vagus nerve stimulation (VNS) improves skilled reach performance and increases reach trajectory consistency in healthy animals. Significance. The CLARA system is the first mouse behavior apparatus that uses markerless pose tracking to provide real-time closed-loop stimulation in response to the outcome of an unconstrained motor task. Additionally, we demonstrate that the CLARA system was essential for our investigating the role of closed-loop VNS stimulation on motor performance in healthy animals. This approach has high translational relevance for developing neurostimulation technology based on complex human behavior.
Enhancing transfer performance across datasets for brain-computer interfaces using a combination of alignment strategies and adaptive batch normalization
Authors: Xu Lichao , Xu Minpeng , Ma Zhen , Wang Kun , Jung Tzyy-Ping , Ming Dong
Published: August 2021

Objective. Recently, transfer learning (TL) and deep learning (DL) have been introduced to solve intra- and inter-subject variability problems in brain-computer interfaces (BCIs). However, current TL and DL algorithms are usually validated within a single dataset, assuming that data of the test subjects are acquired under the same condition as that of training (source) subjects. This assumption is generally violated in practice because of different acquisition systems and experimental settings across studies and datasets. Thus, the generalization ability of these algorithms needs further validations in a cross-dataset scenario, which is closer to the actual situation. This study compared the transfer performance of pre-trained deep-learning models with different preprocessing strategies in a cross-dataset scenario. Approach. This study used four publicly available motor imagery datasets, each was successively selected as a source dataset, and the others were used as target datasets. EEGNet and ShallowConvNet with four preprocessing strategies, namely channel normalization, trial normalization, Euclidean alignment, and Riemannian alignment, were trained with the source dataset. The transfer performance of pre-trained models was validated on the target datasets. This study also used adaptive batch normalization (AdaBN) for reducing interval covariate shift across datasets. This study compared the transfer performance of using the four preprocessing strategies and that of a baseline approach based on manifold embedded knowledge transfer (MEKT). This study also explored the possibility and performance of fusing MEKT and EEGNet. Main results. The results show that DL models with alignment strategies had significantly better transfer performance than the other two preprocessing strategies. As an unsupervised domain adaptation method, AdaBN could also significantly improve the transfer performance of DL models. The transfer performance of DL models that combined AdaBN and alignment strategies significantly outperformed MEKT. Moreover, the generalizability of EEGNet models that combined AdaBN and alignment strategies could be further improved via the domain adaptation step in MEKT, achieving the best generalization ability among multiple datasets (BNCI2014001: 0.788, PhysionetMI: 0.679, Weibo2014: 0.753, Cho2017: 0.650). Significance. The combination of alignment strategies and AdaBN could easily improve the generalizability of DL models without fine-tuning. This study may provide new insights into the design of transfer neural networks for BCIs by separating source and target batch normalization layers in the domain adaptation process.
Features of the numerical solution of bi-characteristic equations by methods of computer mathematics
Authors: Bova Yu I , Kryukovsky A S
Published: August 2021

The features of applying the methods of computer mathematics to the numerical solution of the bi-characteristic system of equations describing the propagation of radio waves in the ionospheric plasma are considered. Based on the comparison of the numerical and exact solutions obtained for the parabolic plasma layer, the accuracy of the numerical solution was investigated.
On the reaction of atmospheric characteristics in the Gulf of Mexico to the origin of hurricanes based on satellite microwave radiometric measurements
Authors: Grankov A G , Milshin A A , Novichikhin E P , Shelobanova N K
Published: August 2021

Based on satellite microwave radiometric measurements, the spatial and temporal variability of the brightness temperature in the spectral band of the resonant radiation of atmospheric water vapor, as well as meteorological parameters in the Gulf of Mexico during the origin and development of the tropical hurricanes Humberto and Lorenzo in September-October 2007, were analyzed. The results of the analysis indicate that large areas of the Gulf of Mexico are involved in the formation of the brightness temperature response to the origin of hurricanes. The role of spatial dispersion of atmospheric moisture content over the Gulf of Mexico is evaluated as a quantitative indicator of the processes of origin and development of the hurricanes Humberto and Lorenzo.
Simulation of microwave spatial field of atmospheric brightness temperature under discontinuous cumulus cloudiness
Authors: Egorov D P , Ilyushin Ya A , Koptsov Ya V , Kutuza B G
Published: August 2021

Planck’s model for random discontinuous cloud fields generation in a three-dimensional computational domain is considered. An algorithm has been developed for computation a 2D picture of downwelling microwave radiation brightness temperature distribution from altitude profiles of the main meteorological parameters, including liquid water profile obtained during the generation of cloud field. The inverse problem of integral moisture content parameters distribution retrieval by means of dual-frequency method is solved. Systematic errors in the cloud liquid water content estimation associated with the use of a homogeneous flat-layered model of the cloud field, which ignores its real, inhomogeneous structure, are investigated.
Short-term forecasting of atmospheric meteorological parameters based on the results of the neural network of a three-band microwave radiometric system
Authors: Rostokin I N , Karyaev V V , Fedoseeva E V , Rostokina E A , Shchukin G G
Published: August 2021

The article considers a variant of inclusion of a neural network into the microwave radiometric system of remote sensing of the atmosphere to perform short-term forecasting of meteorological parameters, based on current measurements of power of own radio-thermal emission of the atmosphere in three frequency bands. The initial data for the training of the neural network- the results of daily microwave radiometric measurements in three frequency bands and data on atmospheric meteorological parameters in the near ground layer obtained using a mobile meteorological station- are indicated. The results of forecasting the temperature and humidity of the near ground layer of the atmosphere based on the current results of microwave radiometric measurements for the current moment and with a two-hour lead time are presented.
Distributed natural areas of Earth covers as verification tool of spaceborne SAR radiometric stability
Authors: Zakharov A , Zakharova L , Sinilo V , Ivanychev E
Published: August 2021

The analysis of the long-term stability of the scattering properties of various types of natural covers was carried out using Japanese PALSAR-1 and PALSAR-2 spaceborne synthetic aperture radar observations. High stability of the reflective properties of the extended objects of the Antarctica and South America, comparable with stability of specialized artificial targets, has been revealed. For that reason, distributed targets under discussion may be considered as suitable targets for spaceborne radars intercalibration and monitoring of their stability.
Calibration of a three-band microwave radiometric system by an external noise signal source
Authors: Fedoseeva E V , Rostokin I N , Rostokina E A , Shchukin G G
Published: August 2021

The article considers a method of solving the problem of calibration of a tri-band microwave radiometric system by an external source of noise signal. The peculiarity of the given method of calibration is the location of the calibrated noise signal source in the base of the common antenna mirror with reception to the common aperture of the system’s illuminator. The questions of technical realization of a noise source as a broadband noise generator taking into account frequency dependence of output noise power value supplemented by an attenuator for obtaining a two-level calibration signal are considered. In article the theoretical positions underlying the given way of calibration in values of measured radio-luminous temperature are resulted, and time dependences of measurements of radio-luminous temperature of atmosphere are shown at an antenna direction in a zenith with inclusion of an external source of a noise signal at performance of calibration of microwave radiometric system.
Classification of slope area types and hydrocarbon accumulation rules in Wuerxun-Beier Depression
Authors: Li Junhui
Published: August 2021

After more than 50 years of exploration and development, Wuerxun-Beier depression has entered a high exploration stage. It is more and more difficult to find large-scale structural reservoirs. Therefore, structural-lithologic reservoirs in slope areas have gradually become the focus of exploration. Based on the overall study and dissection of the depression, the geological differentiation characteristics of the large-scale slope area are discussed. According to the occurrence of the slope, the intensity of tectonic activity, the intensity of source supply and the pattern of synsedimentary fault combination, the slope zone in the study area can be divided into six types, namely, the steep slope with strong source along the fault step type, the compound fault step type of medium slope with strong source, the reverse fault step type of the gentle slope with strong source, and the weak supply type. Different types of slope have different sand control mechanisms and reservoir forming characteristics, such as the source gentle slope forward fault terrace type, the weak source gentle slope reverse fault terrace type and the weak source middle slope forward fault terrace type. Source supply intensity and slope dip control the development type of sedimentary system, the combination of synsedimentary faults and valleys controls the distribution characteristics of sedimentary system. Through exploration practice, significant discoveries have been made on the southwestern, southeastern and northern slopes of Beixi, Wuerxun-Beier depression, which confirms that the slope area is the main breakthrough direction for oil and gas exploration and large-scale reservoir increase in continental fault-depression lake basins.
Study on the evaluation and transformation path of green industrial development in Sichuan Province
Authors: Zhang Jiwen , Yao Jian , Li Xinlong , Zhang Tao
Published: August 2021

This paper calculated the green index of 37 industries in Sichuan province by constructing a comprehensive model reflecting the economic contribution rate and environmental pollution contribution rate of industry, and the K-means method was used for clustering analysis. The results show that the green index of industry in Sichuan is at a good level among the country, but there is still a large development space. Based on the green index of clustering results show that the industry is divided into 4 major categories: encouraged development, optimized development, allowed development and restricted development, and the differentiated countermeasures proposed by the paper based on the research results are the practical needs of the green development of industries in the new era.
Discussion on the design of solar aerator for fish pond
Authors: Rao Guoran , Chen Songtao
Published: August 2021

The solar energy is used as the power of the aerator in the solar aerator for fish pond to provide sufficient oxygen for fishes in pond, which meets the needs of general aquaculture. In this paper, solar energy is used as the power source of aerator, and weak current DC aerator replaces the traditional existing strong alternating aerator. The system comprises of a polycrystalline solar panel square array, solar panel bracket, controller, colloidal battery, DC aeration blower, micro-porous aeration coil, DC-DC regulated adjustable power supply module, DC brushless water spray aerator, etc. The experimental results show that the solar aerator can work for 6.5 hours per day on average. Furthermore, after adding the DC-DC regulated and adjustable power supply module, the voltage and the current of the solar aerator are relatively stable. Therefore, the aerator has a noticeable effect on the dissolved oxygen in the water, and it can effectively and stably provide the necessary oxygen for the fish pond.
“Factory-like” horizontal well plan optimization techniques in tight oil exploration—A case study in Fuyu oil-bearing layer of Y63 well block, Northern Songliao Basin
Authors: Sun Hailei , Zhu Zhengyuan
Published: August 2021

In Zhaoyuan region of Sanzhao Depression, Fuyu oil layer is of considerable resource potential, and its tight reservoir is continuous and extensively oil-bearing. How to improve the deliverability of tight reservoir, however, is still a major problem facing explorationists. As for the sweet spot Y63 in Zhaoyuan region, this paper uses well logging, well testing and laboratory test data to identify the geological characteristics of F II 1, determines the sand body boundaries of the sweet spot by means of seismic attributes and geostatistical inversion, and then carry out batches of horizontal well plans on the same platform. The drilling result of five horizontal wells shows that the oil layer thickness ranges from 934m to 1177m, with an average of 1080m. By comparison with its adjacent straight wells, the deliverability of horizontal well is improved by a factor of 5-12. This proves the advantage and feasibility of the horizontal well plan proposed in this paper.
High frequency sequence stratigraphic framework and sedimentary characteristics of P oil layer in the southern part of A area
Authors: Zhang Xu
Published: August 2021

Based on the high resolution sequence stratigraphy theory, 42 wells and 2745 well logging curves are used to study the evolution of all levels of base level cycles and the development pattern of high-resolution sequence in the P reservoir in the southern part of Songfangtun area. The results show that the 4 sequence interface of the grape flower beds in the Songfangtun area can be divided into 2 medium-term, 5 short term and 12 ultra short term sequences. On this basis, the sedimentary microfacies type and distribution evolution law have been carried out. It is considered that the shallow water delta depositional system is developed in P reservoir in the Songfangtun area. The main development of delta front subfacies is to identify 8 kinds of microfacies such as subwater distributary channel, inter channel, inter channel, slime, overflow sand, mouth fan, estuarine dam, far sand bar and mat sand. The underwater distributary channel sandbodies are widely developed at the front of the delta. Due to frequent bifurcations and diversions, the underwater distributary channel sandbodies cut and overlap each other, forming branches and striped sand bodies. The sandbody reservoir has good physical property and is the main reservoir sand body with oil and gas enrichment. The detailed study of sedimentary microfacies provides a reference for further exploration and development of lithologic reservoirs in this area.
Co-relation between mechanical properties and porosity in thick, thin and thinnest sections of stepped casted workpiece using A-356 Aluminum alloy
Authors: Jamal Quaid , Shah Feroz , Nawaz Ahmad , Bibi Saira , Islam Bilal , Ali Ahad
Published: August 2021

A-356 aluminum alloy stepped casted workpiece were prepared with step casting technique was investigated for the mechanical properties and porosity defects using various gating elements (ingate/runner) profiles. Similarly, casted workpieces were produced using single and double gating elements with circular (vortex free), square and rectangular runner and ingate profiles. Hardness (HV) and ultimate tensile strength (UTS) of the thick section prepared from single circular runner/ingate system was more in comparison to thin and thinnest sections extracted at respective heights. Similarly, hardness and tensile strengths of thick specimen prepared from double ingate/runner having circular shape was found greater in comparison to thin and thinnest sections accordingly. SEM images depicted increase of porosity levels in thin and thinnest sections prepared from single or double within workpiece manufactured from circular runner & ingate arrangements respectively. In addition, X-ray diffraction results further revealed increase in crystallite size, hardness and tensile strength for specimens manufactured through circular profiled single or double runner/ingate arrangement. The prepared specimens also follow inverse Hall-Petch and D
2/%P statistical fit with p < 0.05 between hardness and crystallite size. Hence, the specimen with lower crystallite size or finer grains depicted attenuated mechanical properties due to higher porosity levels. In other words, D
2/%P index ratio value <1.40 (≥95% data points follows) exhibited reductions in mechanical properties accompanied by decreasing crystallite size and vise-versa. Moreover, double gating runner & ingate combination exhibited comparatively lesser pores relative to single gating design. Hence, this study suggests double runner & ingate arrangement accompanied with circular cross-section are appropriate for large size step castings or complicated geometries production in foundries.
Microstructure evolution and corrosion behavior of 316L stainless steel subjected to torsion
Authors: Zhang Pengyan , Han Weixue , Huang Zhenyi , Li Guisheng , Zhang Mingya , Li Jinghui
Published: August 2021

The microstructure evolution of 316L stainless steels subjected to torsion deformation and its corrosion resistance in 1 M H2SO4 solutions were studied. Microstructure evolution of the annealed and torsion-processed samples was characterized by x-ray diffraction and electron backscatter diffraction techniques. The results showed that no martensitic transformation occurred during torsion deformation, while dynamic recrystallization occurred within the samples slowing down the tendency of increasing dislocation density and storage energy. Electrochemical tests including potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) were used in the 1 M H2SO4 solution to evaluate the corrosion resistance of the annealed and torsion-processed samples. The results illustrated that small deformation (torsion for 1 turn) could enhance the corrosion resistance of the 316L stainless steels by increasing the stability of the passive film, the medium deformation (torsion for 3 turns) will deteriorate the corrosion resistance due to high-density dislocations formed during torsion deformation, while large deformation (torsion for 5 turns) could improve the corrosion resistance compared with the medium deformation due to the occurrence of dynamic recrystallization and the high-density deformation twins formed.
Estimations of ambient fine particle and ozone level at a suburban site of Beijing in winter
Authors: Liu Weixuan , Yang Zheng , Liu Qingyang
Published: August 2021

Estimates of PM2.5 and O3 in suburban areas are of importance for assessing exposure risk and epidemiological studies of air pollution where large scale and long-term measurements network are absent. To fulfill this goal, our study develops a flexible approach to predict levels of PM2.5 and O3 at a suburban site of Beijing using multilayer perceptron (MLP) neural network analysis with the inputs of gaseous air pollutants (CO, SO2, NO, and NO2) and meteorological parameters (wind direction, wind speed, temperature, pressure and humidity). Daily ambient data of PM2.5, O3, PM10, CO, SO2, NO, and NO2 were estimated using hourly data collected from January 20 to March 10 in the years from 2016–2020 at a suburban site of Beijing, respectively. Ambient measured levels of PM2.5 and O3 were compared with the output estimates of PM2.5 and O3 through MLP neural network analysis with limited input variables. Overall, MLP neural network analysis could explain 97% of measured PM2.5 mass and 82% of measured O3 level with R2 values of 0.983 and 0.905, respectively. This approach could be helpful for reconstruct historical PM2.5 and O3 levels in suburban areas.
2022 Roadmap on integrated quantum photonics
Authors: Moody Galan , Sorger Volker J , Blumenthal Daniel J , Juodawlkis Paul W , Loh William , Sorace-Agaskar Cheryl , Jones Alex E , Balram Krishna C , Matthews Jonathan C F , Laing Anthony , Davanco Marcelo , Chang Lin , Bowers John E , Quack Niels , Galland Christophe , Aharonovich Igor , Wolff Martin A , Schuck Carsten , Sinclair Neil , Lončar Marko , Komljenovic Tin , Weld David , Mookherjea Shayan , Buckley Sonia , Radulaski Marina , Reitzenstein Stephan , Pingault Benjamin , Machielse Bartholomeus , Mukhopadhyay Debsuvra , Akimov Alexey , Zheltikov Aleksei , Agarwal Girish S , Srinivasan Kartik , Lu Juanjuan , Tang Hong X , Jiang Wentao , McKenna Timothy P , Safavi-Naeini Amir H , Steinhauer Stephan , Elshaari Ali W , Zwiller Val , Davids Paul S , Martinez Nicholas , Gehl Michael , Chiaverini John , Mehta Karan K , Romero Jacquiline , Lingaraju Navin B , Weiner Andrew M , Peace Daniel , Cernansky Robert , Lobino Mirko , Diamanti Eleni , Vidarte Luis Trigo , Camacho Ryan M
Published: August 2021

Integrated photonics will play a key role in quantum systems as they grow from few-qubit prototypes to tens of thousands of qubits. The underlying optical quantum technologies can only be realized through the integration of these components onto quantum photonic integrated circuits (QPICs) with accompanying electronics. In the last decade, remarkable advances in quantum photonic integration have enabled table-top experiments to be scaled down to prototype chips with improvements in efficiency, robustness, and key performance metrics. These advances have enabled integrated quantum photonic technologies combining up to 650 optical and electrical components onto a single chip that are capable of programmable quantum information processing, chip-to-chip networking, hybrid quantum system integration, and high-speed communications. In this roadmap article, we highlight the status, current and future challenges, and emerging technologies in several key research areas in integrated quantum photonics, including photonic platforms, quantum and classical light sources, quantum frequency conversion, integrated detectors, and applications in computing, communications, and sensing. With advances in materials, photonic design architectures, fabrication and integration processes, packaging, and testing and benchmarking, in the next decade we can expect a transition from single- and few-function prototypes to large-scale integration of multi-functional and reconfigurable devices that will have a transformative impact on quantum information science and engineering.
Bilayer MoS2 on silicon for higher terahertz amplitude modulation
Authors: Jakhar Alka , Kumar Prabhat , Husain Sajid , Dhyani Veerendra , Chouksey Abhilasha , Rai Prashant Kumar , Rawat J S , Das Samaresh
Published: August 2021

The terahertz (THz) amplitude modulation has been experimentally demonstrated by employing bilayer molybdenum disulfide (MoS2) on high-resistivity silicon (Si). The Raman spectroscopy and x-ray photoelectron spectra confirm the formation of bilayer MoS2 film. The THz transmission measurements are carried out using a continuous wave (CW) frequency-domain THz system. This reveals the higher modulation depth covering wide THz spectra of 0.1–1 THz at low optical pumping power. The modulation depth up to 72.3% at 0.1 THz and 62.8% at 0.9 THz under low power optical excitation is achieved. After annealing, the strong built-in electric field is induced at the MoS2–Si interface due to p-type doping in MoS2. This improves modulation depth to 86.4% and 79.7%, respectively. The finite-difference time-domain (FDTD) based numerical simulations match well with the experimental results. The higher modulation depth at low optical power, broadband response, low insertion losses, and simplicity in the design are the key attributes of this THz modulator.
Invariant measures on nilpotent orbits associated with holomorphic discrete series
Authors: Božičević Mladen
Published: August 2021

Let

G

R

G_\mathbb R

be a real form of a complex, semisimple Lie group

G
G

. Assume

G

R

G_\mathbb R

has holomorphic discrete series. Let

W

\mathcal W

be a nilpotent coadjoint

G

R

G_\mathbb R

-orbit contained in the wave front set of a holomorphic discrete series. We prove a limit formula, expressing the canonical measure on

W

\mathcal W

as a limit of canonical measures on semisimple coadjoint orbits, where the parameter of orbits varies over the positive chamber defined by the Borel subalgebra associated with holomorphic discrete series.
Existence of partially hyperbolic motions in the 𝑁-body problem
Authors: Burgos J.
Published: August 2021

In the context of the Newtonian

N
N

-body problem, we prove the existence of a partially hyperbolic motion with prescribed positive energy and any initial collisionless configuration. Moreover, it is a free time minimizer of the respective supercritical Newtonian action or equivalently a geodesic ray for the respective Jacobi-Maupertuis metric.
Physiological Impacts of Surgical Mask Coverage of Elastomeric Half-mask Respirator Exhalation Valves in Healthcare Workers
Authors: Zhuang Eileen , Thurman Paul , Chen Hegang H , McDiarmid Melissa A , Hines Stella E
Published: August 2021

Objectives

Elastomeric half-mask respirator (EHMR) use in healthcare increased significantly during the COVID-19 pandemic. Concern for potential release of infectious aerosols from EHMR exhalation valves prompted recommendations to cover them with surgical masks (SMs), thereby improving source control. The physiological and subjective effects of wearing a SM over the exhalation valve of an EHMR, however, are unknown.

Methods

Twelve healthy healthcare worker volunteers completed a 30-min series of simulated healthcare-related tasks, including resting, talking, walking, and bending, proning and supinating a weighted manikin, and performing cardiopulmonary resuscitation. This series recurred three times with different mask configurations—SM only, EHMR only, or EHMR with SM covering the exhalation valve. A transcutaneous sensor continuously measured carbon dioxide (tcPCO2), oxygen saturation (SpO2), and heart rate (HR) from each subject. Subjects scored their rates of perceived exertion (RPE) and levels of discomfort after each round. Physiological parameters and subjective scores were analyzed using mixed linear models with a fixed effect for mask type, activity, age, body mass index (BMI), and gender. Analysis also tested for interaction between mask type and activity.

Results

Physiological parameters remained within normal ranges for all mask configurations but varied by task. Statistically significant but small decreases in mean tcPCO2 (37.17 versus 37.88 mmHg, P < 0.001) and SpO2 (97.74 versus 97.94%, P < 0.001) were associated with wearing EHMR with SM over the exhalation valve compared with EHMR alone. Mean HR did not differ between these mask configurations. Wearing SM only was associated with lower RPE and level of discomfort compared with EHMR, but these subjective scores did not differ when comparing EHMR with SM to EHMR only. Age, BMI, and gender had no significant effect on any outcomes.

Conclusions

Wearing a SM over an EHMR did not produce clinically significant changes in tcPCO2, SpO2, or HR compared with uncovered EHMR during healthcare-related tasks. Covered EHMR use also did not affect perceived exertion or discomfort compared with uncovered EHMR use. Covering the exhalation valve of an EHMR with a SM for source control purposes can be done safely.
High-throughput single-cell RNA-seq data imputation and characterization with surrogate-assisted automated deep learning
Authors: Li Xiangtao , Li Shaochuan , Huang Lei , Zhang Shixiong , Wong Ka-chun
Published: August 2021

Single-cell RNA sequencing (scRNA-seq) technologies have been heavily developed to probe gene expression profiles at single-cell resolution. Deep imputation methods have been proposed to address the related computational challenges (e.g. the gene sparsity in single-cell data). In particular, the neural architectures of those deep imputation models have been proven to be critical for performance. However, deep imputation architectures are difficult to design and tune for those without rich knowledge of deep neural networks and scRNA-seq. Therefore, Surrogate-assisted Evolutionary Deep Imputation Model (SEDIM) is proposed to automatically design the architectures of deep neural networks for imputing gene expression levels in scRNA-seq data without any manual tuning. Moreover, the proposed SEDIM constructs an offline surrogate model, which can accelerate the computational efficiency of the architectural search. Comprehensive studies show that SEDIM significantly improves the imputation and clustering performance compared with other benchmark methods. In addition, we also extensively explore the performance of SEDIM in other contexts and platforms including mass cytometry and metabolic profiling in a comprehensive manner. Marker gene detection, gene ontology enrichment and pathological analysis are conducted to provide novel insights into cell-type identification and the underlying mechanisms. The source code is available at https://github.com/li-shaochuan/SEDIM.
Determining the number of factors in high-dimensional generalized latent factor models
Authors: Chen Y , Li X
Published: August 2021

As a generalization of the classical linear factor model, generalized latent factor models are useful for analysing multivariate data of different types, including binary choices and counts. This paper proposes an information criterion to determine the number of factors in generalized latent factor models. The consistency of the proposed information criterion is established under a high-dimensional setting, where both the sample size and the number of manifest variables grow to infinity, and data may have many missing values. An error bound is established for the parameter estimates, which plays an important role in establishing the consistency of the proposed information criterion. This error bound improves several existing results and may be of independent theoretical interest. We evaluate the proposed method by a simulation study and an application to Eysenck’s personality questionnaire.
Situating Crime Pattern Theory Into The Explanation Of Co-Offending: Considering Area-Level Convergence Spaces
Authors: Rowan Zachary R , Appleby Sarah , McGloin Jean Marie
Published: August 2021

Features of the environment including activity nodes and the level of connectivity in spaces help offenders develop awareness spaces for criminal opportunities. Based on arguments forwarded by Felson, the current study argues these environmental features also facilitate convergence spaces that promote interaction among offenders that increase the likelihood of group crime. Data include street connectivity measures from the Environmental Protection Agency and publicly available arrest information from Baltimore City (2013–16). Findings provide support for the influence of certain activity nodes and pedestrian-oriented street connectivity in explaining group crime. The discussion evaluates how crime pattern theory can be extended to understand the social nature of crime.