bluuebunny/crossref_metadata_2025 huggingface dataset:
Cul3-KLHL20 E3 ubiquitin ligase plays a key role in the arms race between HIV-1 Nef and host SERINC5 restriction
Authors: Li Sunan , Li Rongrong , Ahmad Iqbal , Liu Xiaomeng , Johnson Silas F. , Sun Liangliang , Zheng Yong-Hui
Published: April 2022

HIV-1 must counteract various host restrictions to establish productive infection. SERINC5 is a potent restriction factor that blocks HIV-1 entry from virions, but its activity is counteracted by Nef. The SERINC5 and Nef activities are both initiated from the plasma membrane, where SERINC5 is packaged into virions for viral inhibition or downregulated by Nef via lysosomal degradation. However, it is still unclear how SERINC5 is localized to and how its expression is regulated on the plasma membrane. We now report that Cullin 3-KLHL20, a trans-Golgi network (TGN)-localized E3 ubiquitin ligase, polyubiquitinates SERINC5 at lysine 130 via K33/K48-linked ubiquitination. The K33-linked polyubiquitination determines SERINC5 expression on the plasma membrane, and the K48-linked polyubiquitination contributes to SERINC5 downregulation from the cell surface. Our study reveals an important role of K130 polyubiquitination and K33/K48-linked ubiquitin chains in HIV-1 infection by regulating SERINC5 post-Golgi trafficking and degradation.
Growing urban bicycle networks
Authors: Szell Michael , Mimar Sayat , Perlman Tyler , Ghoshal Gourab , Sinatra Roberta
Published: April 2022

Cycling is a promising solution to unsustainable urban transport systems. However, prevailing bicycle network development follows a slow and piecewise process, without taking into account the structural complexity of transportation networks. Here we explore systematically the topological limitations of urban bicycle network development. For 62 cities we study different variations of growing a synthetic bicycle network between an arbitrary set of points routed on the urban street network. We find initially decreasing returns on investment until a critical threshold, posing fundamental consequences to sustainable urban planning: cities must invest into bicycle networks with the right growth strategy, and persistently, to surpass a critical mass. We also find pronounced overlaps of synthetically grown networks in cities with well-developed existing bicycle networks, showing that our model reflects reality. Growing networks from scratch makes our approach a generally applicable starting point for sustainable urban bicycle network planning with minimal data requirements.
Successes and challenges of implementing teleprehabilitation for onco-surgical candidates and patients’ experience: a retrospective pilot-cohort study
Authors: Drummond Kenneth , Lambert Genevieve , Tahasildar Bhagya , Carli Francesco
Published: April 2022

This study documents the implementation of a multimodal teleprehabilitation program (e.g., completion rate, exercise metrics, and program successes and challenges) for cancer patients undergoing surgery. It also documents the patients’ experience of the program. This pilot-cohort study included adults scheduled for elective thoracic and abdominal cancer resection surgery, referred to the prehabilitation clinic to engage in physical activity, and received a teleprehabilitation program between August 1st, 2020, and February 28th, 2021. The technology platform provided to the patients included a tablet and a wearable device to facilitate communication and data collection. Data collected for this article were acquired through virtual physical activity monitoring in addition to patient charts. Qualitative data collected comprised of successes and challenges of implanting a teleprehabilitation program, in addition to patients’ perspectives of the program. Quantitative data collected comprised of the exercise metrics, perioperative functional outcomes, in addition to the surgical and postoperative outcomes. Ten patients (8 males and 2 females; mean age: 68.3 years, SD 11.96) diagnosed with various thoracoabdominal malignancies were included in the current descriptive study. The successes identified were related to recruitment and assessment, improvement in functional capacity, clinic scheduling and interventions, and optimal medical follow-up. The challenges identified were related to the adoption of the technologies by patients and the multidisciplinary team, the accurate acquisition of patient physical activity data, and the initial costs to acquire the new technologies. Patients were satisfied with the teleprehabilitation program (i.e., services delivered; average appreciation: 96%), and they perceived the technologies provided to be 90% user-friendly. The findings of the current study highlight important concepts in view of the current international health paradigm changes prioritizing remote interventions facilitated through digital communication technologies. It provides important insight into the clinical application of telehealth in elderly populations, notably in the context of acute preoperative cancer care. This article may provide guidance for other cancer care facilities aiming to implement teleprehabilitation programs.
Role of Ce in the enhanced performance of the water oxidation reaction and urea oxidation reaction for NiFe layered double hydroxides
Authors: Fan Jianfeng , Du Xiaoqiang
Published: April 2022

The Ce(OH)3@NiFe LDH material exhibits superior electrocatalytic performance for the water oxidation reaction (at an overpotential of 220 mV@10 mA cm−2) and urea oxidation reaction (at an potential of 1.40 V@10 mA cm−2).
Modulation of architectures and magnetic dynamics in pseudotetrahedral cobalt(ii) complexes
Authors: Zhou Yuting , Li Yuzhu , Xi Jing , Qin Yuanyuan , Cen Peipei , Zhang Yi-Quan , Guo Yan , Ding Yi , Liu Xiangyu
Published: April 2022

Distinct structures and dynamic magnetic behaviours have been observed in two pseudotetrahedral Co(ii) complexes.
Metabolic regulation of (−)-epicatechin and the colonic metabolite 2,3-dihydroxybenzoic acid on the glucose uptake, lipid accumulation and insulin signalling in cardiac H9c2 cells
Authors: García-Díez Esther , López-Oliva María Elvira , Pérez-Jiménez Jara , Martín María Angeles , Ramos Sonia
Published: April 2022

EC and DHBA decrease lipid accumulation, increase glucose uptake and strengthen the insulin-signalling pathway. EC and DHBA modulate the cardiac glucose uptake and lipid accumulation via AKT and AMPK.
Photoexcited sulfenylation of C(sp3)–H bonds in amides using thiosulfonates
Authors: Bi Wen-Zhu , Zhang Wen-Jie , Li Chen-Yu , Shao Lu-Hao , Liu Qing-Pu , Feng Su-Xiang , Geng Yang , Chen Xiao-Lan , Qu Ling-Bo
Published: April 2022

Photoexcited organic dye-catalyzed synthesis of sulfenyl amides through a direct sulfenylation of C(sp3)–H bonds using thiosulfonates as a sulfur source at room temperature.
Polymer-based chemical-nose systems for optical-pattern recognition of gut microbiota
Authors: Tomita Shunsuke , Kusada Hiroyuki , Kojima Naoshi , Ishihara Sayaka , Miyazaki Koyomi , Tamaki Hideyuki , Kurita Ryoji
Published: April 2022

A biomimetic ‘chemical-nose’ composed of twelve block copolymers with aggregation-induced emission units is presented, which can detect sleep disorder in mice from a small amount of microbiome samples (<10 μg) in a short time (<30 min).
Engineering lanmodulin's selectivity for actinides over lanthanides by controlling solvent coordination and second-sphere interactions
Authors: Mattocks Joseph A. , Cotruvo Joseph A. , Deblonde Gauthier J.-P.
Published: April 2022

Nature’s most potent protein for f-elements, lanmodulin, relies on subtle first-sphere/second-sphere interactions to bind metal ions. Dissecting lanmodulin’s binding mechanism yielded variants with enhanced actinide/lanthanide selectivity.
An economical approach for peptide synthesisviaregioselective C–N bond cleavage of lactams
Authors: Muramatsu Wataru , Yamamoto Hisashi
Published: April 2022

An economical, solvent-free, and metal-free method for peptide synthesisviaC–N bond cleavage using lactams has been developed.
A dysprosium single molecule magnet outperforming current pseudocontact shift agents
Authors: Santana Francielli S. , Perfetti Mauro , Briganti Matteo , Sacco Francesca , Poneti Giordano , Ravera Enrico , Soares Jaísa F. , Sessoli Roberta
Published: April 2022

A robust dysprosium(iii) single molecule magnet with large uniaxial magnetic anisotropy induces pseudocontact shifts at almost doubled distance compared to standard shift agents.
Differences in cell death and division rules can alter tissue rigidity and fluidization
Authors: Reddy Gudur Ashrith , Katira Parag
Published: April 2022

Different biophysical triggers of cell death and division events within tissues differentially alter tissue mechanical properties such as rigidity and fluidity, consequently affecting tissue reorganization, growth and invasion dynamics.
Whole‐line fault analysis method for unbalanced distribution networks with inverter interfaced distributed generators
Authors: Li Yingliang , Wang Deming
Published: April 2022

The integration of the inverter interfaced distributed generators (IIDGs) challenges the conventional fault analysis in distribution networks. However, the existing analysis methods mainly focus on the fault occurring at the network buses and little research has been done to analyse the whole‐line faults. To extend the fault analysis methods, this paper proposed a phase domain estimation method. The new method was designed to analyse the whole‐line faults in unbalanced distribution networks, considering the control strategy and fault‐ride‐through (FRT) capability of IIDG. A canonical method was developed and a compensation method was utilised, avoiding constructing the entire bus matrix and predefining the fault boundary conditions. Moreover, the new method is robust and can be used to analyse the simultaneous faults as well. Finally, the proposed method was programmed in MATLAB and different scenarios were tested on an unbalanced network. The calculation results were examined by the simulations, which verified the effectiveness of the new method. The new method can analyse whole‐line fault in unbalanced networks with IIDGs connection, extending the current fault analysis methods and providing foundations for relay protection.
Well-balanced positivity preserving adaptive moving mesh central-upwind schemes for the Saint-Venant system
Authors: Kurganov Alexander , Qu Zhuolin , Wu Tong
Published: April 2022

We extend the adaptive moving mesh (AMM) central-upwind schemes recently proposed in Kurganov et al. [Commun. Appl. Math. Comput. 3 (2021) 445–479] in the context of one- (1-D) and two-dimensional (2-D) Euler equations of gas dynamics and granular hydrodynamics, to the 1-D and 2-D Saint-Venant system of shallow water equations. When the bottom topography is nonflat, these equations form hyperbolic systems of balance laws, for which a good numerical method should be capable of preserving a delicate balance between the flux and source terms as well as preserving the nonnegativity of water depth even in the presence of dry or almost dry regions. Therefore, in order to extend the AMM central-upwind schemes to the Saint-Venant systems, we develop special positivity preserving reconstruction and evolution steps of the AMM algorithms as well as special corrections of the solution projection step in (almost) dry areas. At the same time, we enforce the moving mesh to be structured even in the case of complicated 2-D computational domains. We test the designed method on a number of 1-D and 2-D examples that demonstrate robustness and high resolution of the proposed numerical approach.
A combined EBSD/nanoindentation study of dislocation density gradients near grain boundaries in a ferritic steel
Authors: Chamma Layal , Pipard Jean-Marc , Arlazarov Artem , Richeton Thiebaud , Lecomte Jean-Sébastien , Berbenni Stéphane
Published: April 2022

Microstructural internal lengths play an important role on the local and macroscopic mechanical behaviors of steels. In this study, the dislocation density gradients near grain boundaries in a ferritic steel are investigated using SEM/EBSD together with instrumented nanoindentation for undeformed and pre-deformed aluminum-killed steels (Al-k) at 3% and 18% tensile plastic strains. The effect of the distance to grain boundaries on Geometrically Necessary Dislocations (GND) densities is first determined by analyzing orientation gradients from 2D-EBSD maps. Then, nanohardness measurements are performed in the vicinity of grain boundaries. Data analyses show a clear correlation between the spatial gradients of GND density and the ones of nanohardness. Using a mechanistic model, the total dislocation densities are estimated from the measured nanohardness values. From both GND and total dislocation density profiles, the value of an internal length, denoted λ, is estimated from the analysis of dislocation density gradients near grain boundaries. At the end, the capabilities of 2D-EBSD and nanoindentation methods to assess this value are discussed.
The QICK (Quantum Instrumentation Control Kit): Readout and control for qubits and detectors
Authors: Stefanazzi Leandro , Treptow Kenneth , Wilcer Neal , Stoughton Chris , Bradford Collin , Uemura Sho , Zorzetti Silvia , Montella Salvatore , Cancelo Gustavo , Sussman Sara , Houck Andrew , Saxena Shefali , Arnaldi Horacio , Agrawal Ankur , Zhang Helin , Ding Chunyang , Schuster David I.
Published: April 2022

We introduce a Xilinx RF System-on-Chip (RFSoC)-based qubit controller (called the Quantum Instrumentation Control Kit, or QICK for short), which supports the direct synthesis of control pulses with carrier frequencies of up to 6 GHz. The QICK can control multiple qubits or other quantum devices. The QICK consists of a digital board hosting an RFSoC field-programmable gate array, custom firmware, and software and an optional companion custom-designed analog front-end board. We characterize the analog performance of the system as well as its digital latency, important for quantum error correction and feedback protocols. We benchmark the controller by performing standard characterizations of a transmon qubit. We achieve an average gate fidelity of Favg=99.93%. All of the schematics, firmware, and software are open-source.
Cavity-dumping a single infrared pulse from a free-electron laser for two-color pump–probe experiments
Authors: Janssen T. , Davies C. S. , Gidding M. , Chernyy V. , Bakker J. M. , Kirilyuk A.
Published: April 2022

Electromagnetic radiation in the mid- to far-infrared spectral range represents an indispensable tool for the study of numerous types of collective excitations in solids and molecules. Short and intense pulses in this terahertz spectral range are, however, difficult to obtain. While wide wavelength-tunability is easily provided by free-electron lasers, the energies of individual pulses are relatively moderate, on the order of microjoules. Here, we demonstrate a setup that uses cavity-dumping of a free-electron laser to provide single, picosecond-long pulses in the mid- to far-infrared frequency range. The duration of the Fourier-limited pulses can be varied by cavity detuning, and their energy was shown to exceed 100 µJ. Using the aforementioned infrared pulse as a pump, we have realized a two-color pump–probe setup facilitating single-shot time-resolved imaging of magnetization dynamics. We demonstrate the capabilities of the setup first on thermally induced demagnetization and magnetic switching of a GdFeCo thin film and second by showing a single-shot time-resolved detection of resonant phononic switching of the magnetization in a magnetic garnet.
An alternative excitation method for electrical impedance tomography
Authors: Cui Ziqiang , Yang Pengyu , Li Xuan , Wang Huaxiang
Published: April 2022

Electrical impedance tomography (EIT) can be utilized to image the conductivity distribution of material under test. The EIT measurements depend on the quality in the current injection and voltage measuring circuits. The current source plays a vital role in the EIT instruments. In most of the research studies, the push–pull current sources were employed for the source and sink signal generation. It usually requires frequent calibration to achieve proper functioning, especially for the sweeping frequency measurements. In this paper, an alternative excitation method has been proposed for simplifying the design of the current source in EIT instruments, which aims to achieve the performance of the push–pull current source by using a single-ended current source. It could offer the following advantages: (1) hardware simplification and (2) reduced requirements on current source calibration. The corrected measurements could be consistent with that using push–pull excitation, as confirmed by the numerical simulations. In addition, the reconstructed images have also been investigated to illustrate the effectiveness of the proposed method.
Network approach reveals the spatiotemporal influence of traffic on air pollution under COVID-19
Authors: Wang Weiping , Yang Saini , Yin Kai , Zhao Zhidan , Ying Na , Fan Jingfang
Published: April 2022

Air pollution causes widespread environmental and health problems and severely hinders the quality of life of urban residents. Traffic is critical for human life, but its emissions are a major source of pollution, aggravating urban air pollution. However, the complex interaction between traffic emissions and air pollution in cities and regions has not yet been revealed. In particular, the spread of COVID-19 has led various cities and regions to implement different traffic restriction policies according to the local epidemic situation, which provides the possibility to explore the relationship between urban traffic and air pollution. Here, we explore the influence of traffic on air pollution by reconstructing a multi-layer complex network base on the traffic index and air quality index. We uncover that air quality in the Beijing–Tianjin–Hebei (BTH), Chengdu–Chongqing Economic Circle (CCS), and Central China (CC) regions is significantly influenced by the surrounding traffic conditions after the outbreak. Under different stages of the fight against the epidemic, the influence of traffic in some regions on air pollution reaches the maximum in stage 2 (also called Initial Progress in Containing the Virus). For the BTH and CC regions, the impact of traffic on air quality becomes bigger in the first two stages and then decreases, while for CC, a significant impact occurs in phase 3 among the other regions. For other regions in the country, however, the changes are not evident. Our presented network-based framework provides a new perspective in the field of transportation and environment and may be helpful in guiding the government to formulate air pollution mitigation and traffic restriction policies.
Measurement of the stray light in the Advanced Virgo input mode cleaner cavity using an instrumented baffle
Authors: Ballester O , Blanch O , Cardiel L , Cavalli-Sforza M , Chiummo A , García C , Illa J M , Karathanasis C , Kolstein M , Martínez M , Menéndez-Vázquez A , Mir Ll M , Mundet J , Romero-Rodríguez A , Serrano D , Yamamoto H
Published: April 2022

A new instrumented baffle was installed in Spring 2021 at Virgo surrounding the suspended mirror in the input mode cleaner triangular cavity. It serves as a demonstrator of the technology designed to instrument the baffles in the main arms in the near future. We present, for the first time, results on the measured scattered light distribution inside the cavity as determined by the new device using data collected between May and July 2021, with Virgo in commissioning phase and operating with an input laser power in the cavity of 28.5 W. The sensitivity of the baffle is discussed and the data is compared to scattered light simulations.
Frequency-selective signal enhancement by a passive dual coil resonator for magnetic particle imaging
Authors: Pantke Dennis , Mueller Florian , Reinartz Sebastian , Philipps Jonas , Mohammadali Dadfar Seyed , Peters Maximilian , Franke Jochen , Schrank Franziska , Kiessling Fabian , Schulz Volkmar
Published: April 2022

Objective. Magnetic particle imaging (MPI) visualizes the spatial distribution of magnetic nanoparticles. MPI already provides excellent temporal and good spatial resolution, however, to achieve translation into clinics, further advances in the fields of sensitivity, image reconstruction and tracer performance are needed. In this work, we propose a novel concept to enhance the MPI signal and image resolution by a purely passive receive coil insert for a preclinical MPI system. Approach. The passive dual coil resonator (pDCR) provides frequency-selective signal enhancement. This is enabled by the adaptable resonance frequency of the pDCR network, which is galvanically isolated from the MPI system and composed of two coaxial solenoids connected via a capacitor. The pDCR aims to enhance frequency components related to high mixing orders, which are crucial to achieve high spatial resolution. Main Results. In this study, system matrix measurements and image acquisitions of a resolution phantom are carried out to evaluate the performance of the pDCR compared to the integrated receive unit of the preclinical MPI and a dedicated rat-sized receive coil. Frequency-selective signal increase and spatial resolution enhancement are demonstrated. Significance. Common dedicated receive coils come along with noise-matched receive networks, which makes them costly and difficult to reproduce. The presented pDCR is a purely passive coil insert that gets along without any additional receive electronics. Therefore, it is cost-efficient, easy-to-handle and adaptable to other MPI scanners and potentially other applications providing the basis for a new breed of passive MPI receiver systems.
Physical performance of adaptive axial FOV PET scanners with a sparse detector block rings or a checkerboard configuration
Authors: Karakatsanis Nicolas A , Nehmeh Mohammad H , Conti Maurizio , Bal Girish , González Antonio J , Nehmeh Sadek A
Published: April 2022

Objective. Using Monte-Carlo simulations, we evaluated the physical performance of a hypothetical state-of-the-art clinical PET scanner with adaptive axial field-of-view (AFOV) based on the validated GATE model of the Siemens Biograph VisionTM PET/CT scanner. Approach. Vision consists of 16 compact PET rings, each consisting of 152 mini-blocks of 5 × 5 Lutetium Oxyorthosilicate crystals (3.2 × 3.2 × 20 mm3). The Vision 25.6 cm AFOV was extended by adopting (i) a sparse mini-block ring (SBR) configuration of 49.6 cm AFOV, with all mini-block rings interleaved with 16 mm axial gaps, or (ii) a sparse mini-block checkerboard (SCB) configuration of 51.2 cm AFOV, with all mini-blocks interleaved with gaps of 16 mm (transaxial) × 16 mm (axial) width in checkerboard pattern. For sparse configurations, a ‘limited’ continuous bed motion (limited-CBM) acquisition was employed to extend AFOVs by 2.9 cm. Spatial resolution, sensitivity, image quality (IQ), NECR and scatter fraction were assessed per NEMA NU2-2012. Main Results. All IQ phantom spheres were distinguishable with all configurations. SBR and SCB percent contrast recovery (% CR) and background variability (% BV) were similar (p-value > 0.05). Compared to Vision, SBR and SCB %CRs were similar (p-values > 0.05). However, SBR and SCB %BVs were deteriorated by 30% and 26% respectively (p-values < 0.05). SBR, SCB and Vision exhibited system sensitivities of 16.6, 16.8, and 15.8 kcps MBq−1, NECRs of 311 kcps @35 kBq cc−1, 266 kcps @25.8 kBq cc−1, and 260 kcps @27.8 kBq cc−1, and scatter fractions of 31.2%, 32.4%, and 32.6%, respectively. SBR and SCB exhibited a smoother sensitivity reduction and noise enhancement rate from AFOV center to its edges. SBR and SCB attained comparable spatial resolution in all directions (p-value > 0.05), yet, up to 1.5 mm worse than Vision (p-values < 0.05). Significance. The proposed sparse configurations may offer a clinically adoptable solution for cost-effective adaptive AFOV PET with either highly-sensitive or long-AFOV acquisitions.
Efficiency improvement of an E × B Penning discharge source by enhanced cross-field transport of electrons
Authors: Kim June Young , Choi Jinyoung , Choi Jaeyoung , Hwang Y S , Chung Kyoung-Jae
Published: April 2022

Precise control of the particle motion in externally applied electric and magnetic fields is of great significance in the development of the E × B source to generate high-density plasma and deliver a stable ion beam current. Especially, in the E × B Penning discharge source, the heating and energy relaxation of the beam electrons is concentrated in the plasma column along the magnetic field line. Plasma researchers have thus far focused on the relevant physical phenomena of the partially magnetized plasma that arises from the gradient of the plasma properties in the E × B Penning source. Here, we point out that current methods of radially centered electron confinement do not guarantee efficient ion beam extraction, and newly introduce the improvement of the efficiency of a cylindrical E × B Penning source targeting radial extraction of ion beam. We concentrate on the method to enhance the cross-field transport of electrons toward the extraction region. The generation of a spatially asymmetric sheath structure allows the beam and energetic electrons to be transported to the extraction region via the E × B drift of the electrons. The transported electrons contribute to expansion of the electron heating and ionization regions to the extraction region by breaking of axial symmetry of the sheath, thereby increasing the temperature and density of the electrons in the extraction region as the magnetic field strength increases. The enhanced discharge efficiency defined as the ratio of the electron density to the discharge current is noticeable, recording approximately twice the improved efficiency compared to the conventional mode with symmetric sheath structure.
Low Mass Stars as Tracers of Star and Cluster Formation
Authors: Megeath S. T. , Gutermuth R. A. , Kounkel M. A.
Published: April 2022

We review the use of young low mass stars and protostars, or young stellar objects (YSOs), as tracers of star formation. Observations of molecular clouds at visible, infrared, radio and X-ray wavelengths can identify and characterize the YSOs populating these clouds, with the ability to detect deeply embedded objects at all evolutionary stages. Surveys with the Spitzer, Herschel, XMM-Newton and Chandra space telescopes have measured the spatial distribution of YSOs within a number of nearby (<2.5 kpc) molecular clouds, showing surface densities varying by more than three orders of magnitude. These surveys have been used to measure the spatially varying star formation rates and efficiencies within clouds, and when combined with maps of the molecular gas, have led to the discovery of star-forming relations within clouds. YSO surveys can also characterize the structures, ages, and star formation histories of embedded clusters, and they illuminate the relationship of the clusters to the networks of filaments, hubs and ridges in the molecular clouds from which they form. Measurements of the proper motions and radial velocities of YSOs trace the evolving kinematics of clusters from the deeply embedded phases through gas dispersal, providing insights into the factors that shape the formation of bound clusters. On 100 pc scales that encompass entire star-forming complexes, Gaia is mapping the young associations of stars that have dispersed their natal gas and exist alongside molecular clouds. These surveys reveal the complex structures and motions in associations, and show evidence for supernova driven expansions. Remnants of these associations have now been identified by Gaia, showing that traces of star-forming structures can persist for a few hundred million years.
A Conditional Autoencoder for Galaxy Photometric Parameter Estimation
Authors: Yin Jun E. , Eisenstein Daniel J. , Finkbeiner Douglas P. , Protopapas Pavlos
Published: April 2022

Astronomical photometric surveys routinely image billions of galaxies, and traditionally infer the parameters of a parametric model for each galaxy. This approach has served us well, but the computational expense of deriving a full posterior probability distribution function is a challenge for increasingly ambitious surveys. In this paper, we use deep learning methods to characterize galaxy images, training a conditional autoencoder on mock data. The autoencoder can reconstruct and denoise galaxy images via a latent space engineered to include semantically meaningful parameters, such as brightness, location, size, and shape. Our model recovers galaxy fluxes and shapes on mock data with a lower variance than the Hyper Suprime-Cam photometry pipeline, and returns reasonable answers even for inputs outside the range of its training data. When applied to data in the training range, the regression errors on all extracted parameters are nearly unbiased with a variance near the Cramr-Rao bound.
Understanding the Impact of Semi-numeric Reionization Models when Using CNNs
Authors: Zhou Yihao , La Plante Paul
Published: April 2022

Interpreting 21 cm measurements from current and upcoming experiments like HERA and the SKA will provide new scientific insights and exciting implications for astrophysics and cosmology regarding the Epoch of Reionization (EoR). Several recent works have proposed using machine learning methods, such as convolutions neural networks (CNNs), to analyze images of reionization generated by these experiments since they could take full advantage of the information contained in the image. Generally, these studies have used only a single semi-numeric method to generate the input 21 cm data. In this work, we investigate the extent to which training CNNs for reionization applications depends on the underlying semi-numeric models. Working in the context of predicting CMB τ from 21 cm images, we compare networks trained on similar data sets from 21cmFAST and zreion, two widely used semi-numeric reionization methods. We show that neural networks trained on input data from only one model produce poor predictions on data from the other model. Satisfactory results are only achieved when both models are included in the training data. This finding has important implications for future analyzes on observation data, and encourages the use of multiple models to produce images that capture the full complexity of the EoR.
Experimental method of Guide wave based on piezoelectric transducers under high temperature
Authors: Xue Zhaopeng , Qiu Lei , Zheng Hui , Xiong Ke
Published: April 2022

In recent years, the importance of Structural health monitoring (SHM) has been widely recognized. Among all the SHM methods, Guide Wave (GW) based SHM method using bonded piezoelectric transducers proves promising for its sensitivity to minor damage and minor amplitude loss in the large monitoring area. The thermal protection structure (TPS) is the most fundamental guarantee to ensure the safety of aerospace vehicles, and its structural health monitoring has great safety significance and economic value; however, it is often used in high-temperature environments. Conventional GW experimental methods fail in high-temperature environments due to the effects of high-temperature environments, so experimental methods for stable and reliable acquisition of GW signals at high temperatures need to be considered. In this paper, an experimental method for regular purchase of GW signals in a high-temperature environment, which uses a high-temperature sensor, a high-temperature resistant glue, and a high-temperature integration process, is proposed. The experimental results show that the practical method can obtain stable and reliable GW signals at 200°C, beneficial for damage monitoring in high-temperature environments.
Effect of Pre-creep Time on Creep Life of Nickel-based Single Crystal Superalloy CMSX-4
Authors: Xing Yuming , Sun Tong , Hu Xiaoan
Published: April 2022

The effect of overheating with different time on creep life and strain curve of CMSX-4 nickel-based single crystal superalloy was studied. The overheating tests at different temperatures and stresses were carried out. The tests results showed that the duration of the second stage of creep would be reduced when the overheating happened at the beginning of the creep test. The deformation of the alloy quickly entered the third stage of creep, which obviously reduces the creep life and total strain of the material. When the overheating occurs in the second stage of creep, the rate of strain would increase after overheating and then the total creep life decreased. When the overheating was introduced at the beginning of the creep tests, the strain accumulation during the overheating was greater than that in the second stage of creep. However, the rate of strain after the overheating at the beginning is lower than that in the second stage of creep.
Research on rapid batch test of whole star based on pulsating production line
Authors: Li Yongqiang , Dai jianfeng , Zhao Chuan , Zhang Shaopo
Published: April 2022

In recent years, small satellites at home and abroad have been developing rapidly, and constellation have been deeply studied and applied. In particular, a series of commercial satellites companies led by SpaceX in the United States have successfully launched a number of satellites for network formation, and the annual output of their small satellites can reach 1000 magnitude. At present, China is also in the stage of rapid development of all kinds of small satellites , and the annual production of small satellites is also increasing rapidly, in order to adapt to the characteristics of large number of small satellites, short development period and rapid launch and deployment, it is urgent to study the matching test and test technology with the characteristics of batch, rapid, intelligent and efficient. In this paper, the rapid batch test research based on pulsating production line is carried out for the development of small satellites. Based on the establishment of satellite pulsation test system, the test mode, test method and on-line standard of key subsystem are studied. The research results were successfully applied to the batch test of a certain type of satellite. In the factory test stage, multiple satellites completed the test within 347 hours and left the factory at the same time, which greatly improved the test efficiency and laid a certain foundation for comprehensively forming the capacity of parallel and rapid batch test of multiple small satellites.
Research on Embedded Detection System Based on Intelligent Pressure Transmitter
Authors: Zhang Lin-rui , Xiao Jun , Zhang Wei-wei , Zhang Xu-guang
Published: April 2022

A new development scheme of check equipment for recoil device is designed. In view of the existing reverse recoil device check there is a long time to prepare, data interpretation and difficult problems, the application of advanced touch technology and sensor technology, completed the embedded test system scheme based on intelligent pressure transmitter design, can quickly test reverse recoil device to check the key parameters, and be able to compare the interpretation of data in real-time, Shorten the inspection time of recoil device and improve the accuracy of test data. The simulation research of the scheme design system is carried out in the computer of LINUX system. Through the simulation, it is found that each system module can work correctly and normally, with higher generality and artificial intelligence.
Study on Improvement of Spacer Ring of an Aero-engine Considering Fit Tolerance
Authors: Wu Pei , Qian Zhengming , Lu Jin , Mi Dong
Published: April 2022

Aiming at the fatigue crack failure of a spacer ring of an aero-engine, the fracture analysis and finite element analysis of the spacer ring failure were carried out, the cause of the failure was accurately located, and an improvement plan was proposed for the spacer ring according to the analysis results. The equivalent stress of the spacer ring has decreased significantly, and the improved spacer ring has passed the test verification of parts and the whole engine, which proves the effectiveness of the improvement. The method used in this paper can provide a reference for the design and improvement of similar structures in aeroengines.
Design of Ionospheric TEC Gradient Anomaly Detection Platform Based on GNSS
Authors: Liu Mingyuan , Hu Tieqiao
Published: April 2022

Ionospheric anomalies can seriously threaten important flight phases such as approach and landing, so accurate real-time monitoring is necessary. In this paper, an ionospheric anomaly gradient detection platform is designed for satellite navigation receiver. Based on GNSS observation data, the spatial gradient of ionospheric vertical total electron content is calculated, and anomaly ionospheric gradient is detected using generalized likelihood ratio test method. To verify the correctness of detection results, rate of TEC change index is also calculated for comparison. Simulation results show that the platform can detect ionospheric anomaly gradient state fast and accurately, and the proposed approach can used by GNSS receivers to detect ionospheric anomaly.
Fade probability simulation analysis for aircraft platform wireless optical communication based on Hermite-Gaussian beam
Authors: Liu Xin , Zhang Yu , Jiang Dagang , Qin Kaiyu
Published: April 2022

Wireless optical communication technology can provide larger channel capacity for aircraft platforms which has great potentiality. In the application scenario of aircraft platform, the pointing error is inevitable. This study analyzes the fade probability of the link based on Hermite-Gaussian beam by using single-layer phase screen with pointing error simulation method and comparing with Gaussian beam. The higher order Hermite-Gaussian beam shows better link stability performance. Atmosphere turbulence has obvious effect on fade probability when the standard variance of pointing error is small, with the increase of standard variance of pointing error, the major influence factor for fade probability is pointing error rather than atmosphere turbulence.
Research and application of Civil Aircraft Function analysis Technology based on SysML Modeling
Authors: Zhang Jun , Li Piao
Published: April 2022

The design and development of civil aircraft is a systematic engineering project with high precision and high complexity. Traditional aircraft requirements are based on document transmission, which is not intuitive and logical, and are easy to miss requirements in different scenarios The Model-based function analysis is a method that can identify and define all elements of a certain function. In the process of function analysis, the relation between the function interfaces can be determined and the relative requirements can be obtained, which can consequently ensure the validity and integrity of aircraft functional requirements. The functional modeling analysis is carried out based on a SysML model in this paper, and the function is described from the perspective of structural level, behavioral level and activity level by using graphical and hierarchical expression. The internal logic of the function is analyzed in depth to obtain the functional requirements of the aircraft.
Fault Modeling and Simulation of Engine Driven Pump in Aircraft Hydraulic System
Authors: Han Bingjie , Niu Wei , Yan Tanbao
Published: April 2022

The structure of engine driven pump in aircraft hydraulic system is complex, its fault forms are diverse, and the fault transmission path is complex and multi factor coupling. In view of the above problems, based on the in-depth analysis of the working principle of the engine driven pump, the engine driven pump model is established, and the leakage fault injection mechanism of the friction pair is added. The relationship between the flow fluctuation characteristics of engine driven pump and the changes of pump spindle speed, swashplate inclination and pump outlet cavity volume are obtained through model simulation analysis. The mechanism of internal leakage fault of plunger pair, port pair and slipper pair are analyzed, the influence of leakage clearance parameters on key performance indexes such as pump pressure and flow are simulated, and the simulation test data of internal leakage fault of pump are obtained. The simulation results show that the inclination angle of swashplate and spindle speed are positively correlated with the output flow of the pump. The increase of pump outlet volume can effectively alleviate the pressure and flow fluctuation behind the pump. In addition, when the radial clearance of the plunger pair of this type of pump exceeds 0.2mm, the pump fault characteristics begin to appear. At the same time, the load change behind the pump will affect the characterization of the fault of internal leakage of the pump.
Method of civil aircraft emergency electrical power requirement analysis based on Systems Engineering
Authors: Zhao Zhiqiao , Zhang Jun
Published: April 2022

In this paper, the minimum function of civil aircraft power supply emergency is defined based on the model- based system engineering method and the principle of ensuring aircraft flight safety. Through functional architecture-logical architecture-physical architecture modeling, realize the mapping from minimum functions to minimum equipment. The system equipment that needs to work under the emergency electrical power supply of each aircraft system is sorted out from the forward direction, and the electricity requirements of the electrical equipment in different scenarios are analyzed statistically, and then the emergency electrical power requirements of the whole aircraft are obtained as the design input of the electrical power system.
A Novel Conflicting Evidence Combination Method for Fault Diagnosis of Civil Aircraft Electrical System
Authors: Jiang Xiaoting
Published: April 2022

D-S Evidence theory plays an important role in fault diagnosis of civil aircraft electrical system, but it is still difficult to deal with highly conflicting evidence. This paper introduces the idea of grey relational analysis, and proposes a new conflicting evidence combination method. The grey relational degree is used for calculating evidence’s credibility degree, by which conflicting evidence was processed before combination according to traditional D-S combination rule. One numerical example is employed and implemented. Through analysis and comparison of the combined results, of the existing alternatives, the proposed method shows better convergence and accuracy. It can effectively accelerate the fault diagnosis of the civil aircraft electrical system.
Study on the logical relationship between system safety and PMMEL project
Authors: Li Huan , Zheng You Shi
Published: April 2022

The Master Minimum Equipment List (MMEL) is an important technical manual for civil aircraft to meet release conditions and achieve release with failures, and it is also a key reference manual for airlines to develop the minimum equipment list. This paper firstly elaborates the relationship between PMMEL, MMEL and MEL, initially studies the system safety assessment process, and focuses on the logical relationship between system safety and PMMEL project development by detailing the role of system safety assessment FHA, FMEA and FTA in the development and analysis process of PMMEL during the aircraft development phase, to ensure the PMMEL work and The logical relationship between system safety and PMMEL project development is discussed to ensure the close integration between PMMEL work and civil aircraft development, to provide theoretical basis for manufacturers to fully consider the design of PMMEL in the development phase, and then to improve the capability of the developed aircraft with failure release.
Design and Actual Data Analysis of Chang’E-5 Landing Region Microwave Backscatter Coefficient
Authors: Niu Wenbo , Pan Lin , Li Shuanlao , Zhang Aijun , Dang Hongxing , Tan Xiaomin
Published: April 2022

Chang’E-3 landed at the north part of the Mare Imbrium on 14 December 2013, Chang’E-4 landed at South Pole’s Aitken Basin on 3 January 2019 and Chang’E-5 landed at Rümker region in northern Oceanus Procellarum on 1 December 2020. The microwave range and velocity sensor (MRVS) on the lander provided the range and velocity information relative to the lunar surface during the powered descent phase, ensuring landing softly. In this paper, we use the lunar surface backscatter coefficient of Ka-band which was analyzed from the telemetry of MRVS equipped on Chang’E-3 and Chang’E-4, as for the important design basis of Chang’E-5 MRVS; at the same time, actual data is analyzed from the telemetry of Chang’E-5 sensor, and the accumulated analysis of lunar surface backscatter coefficient as the important reference will be used in the future MRVS design and lunar detection.
A study on development of intelligent ground-based air defense radar under the background of modern war
Authors: Yang PENG
Published: April 2022

The new characteristics of modern war put forward new requirements for intelligent ground-based air defense radar. This paper refines the new characteristics of modern war from the aspects of combat object, combat environment and combat style; Based on this, from the perspective of adapting to modern war, this paper analyzes and summarizes the intelligent development of ground-based air defense radar in intelligent perception, resource allocation, man-radar integration and so on, which plays a guiding role in the theoretical research and engineering realization of ground-based air defense radar technology. In addition, the combat effectiveness of intelligent and traditional ground air defense radar is evaluated by analytic hierarchy process, which can be used as a reference for subsequent research.
The Research on Evasion Strategy of Unpowered Aircraft Based on Deep Reinforcement Learning
Authors: Chen Keqin , Lei Jianchang , Li Bin
Published: April 2022

For the pursuit-evasion (PE) game, this paper proposes an evasion strategy with coordinated control of angle of attack, bank angle and body morphing control using deep reinforcement learning. Considering the evasion and ballistic regression of the aircraft, the specified miss distance (SMD) and residual energy are used as the optimization objectives, to acquire the optimal control strategy against the encounter with pursuer in the terminal guidance phase. For the problem of sparse rewards, reward reshaping cannot be performed for this problem, we modify DQN algorithm with the mechanism of Monte-Carlo reinforcement learning to improve the sampling efficiency and realize the end-to-end learning. Finally, the linear analytical solution of the problem based on SMD is analyzed theoretically. With it, the strategy obtained by reinforcement learning is compared and explained.
Influence of atmospheric density and area-to-mass errors on orbit prediction accuracy
Authors: Hao Yimeng , Zhang Shuo , Zheng Xiaoyu , Qu Jinye
Published: April 2022

Due to the fact that the space is becoming increasingly congested, there is a high requirement for the orbit prediction accuracy of space targets to support collision warning tasks. This is especially true for space debris with high area-to-mass ratio and low orbit altitude. This paper focuses on the along-track position error caused by the atmospheric density error and area-to-mass ratio error for targets with near-circular orbit in the orbit prediction. We derive a semi-analytical expression to describe the along-track position error, and the expression’s validity is evaluated by a goodness-of-fit index compared with the simulated “true” along-track position error. The simulation is based on Encke’s special perturbation method, in which the drag error is treated as a perturbation. The drag error is modeled by the difference between the JB2008 and MISIS density model and the sinusoidal oscillation error model concerning the inexact area-to-mass ratio. Furthermore, targets with various orbit altitudes ranging from 300km to 800km are selected to investigate whether the along-track position error can meet the collision warning requirements.