bluuebunny/crossref_metadata_2025 huggingface dataset:
Regio- and stereo-selective construction of cis-indeno[1,2-c]isoxazoles via a C–H allylation/1,3-dipolar cycloaddition cascade
Authors: Zhu Man , Zhang Yanan , Tian Miaomiao , Li Xingwei , Liu Bingxian , Chang Junbiao
Published: September 2022

Synthesis of fused cis-indole[1,2-c]isoxazoles with excellent regio- and stereo-selectivity via a rhodium-catalyzed C–H allylation/intramolecular 1,3-dipolar cycloaddition cascade has been realized.
Ratiometric fluorescence sensing of temperature based on perovskite nanocrystals and rhodamine B doped electrospun fibers
Authors: Tan Xiaohong , Lu Heng , Zhou Yanmei , Wu Shaoru , Huang Guobin , Wang Xudong , Zeng Jingbin , Li Feiming , Cai Zhixiong , Zhang Maosheng
Published: September 2022

Sensing temperature (T) has gained great attention since T is the most important parameter in daily life, scientific research and industry.
Biorefinery of galacturonic acid using a biofuel cell as a reactor
Authors: Nakagawa Tomoe , Abe Hayato , Gessei Tomoko , Takeda Kouta , Igarashi Kiyohiko , Nakamura Nobuhumi
Published: September 2022

A reactor based on an enzymatic biofuel cell (an EBFC reactor) was constructed to simultaneously generate electricity and chemical products from biomass.
Radical generation enabled by photoinduced N–O bond fragmentation
Authors: McClain Edward J. , Wortman Alan K. , Stephenson Corey R. J.
Published: September 2022

Recent advances in synthetic chemistry have seen a resurgence in the development of methods for visible light-mediated radical generation.
Surface differences of oxide nanocrystals determined by geometry and exogenously coordinated water molecules
Authors: Chen Junchao , Wu Xin-Ping , Hope Michael A. , Lin Zhiye , Zhu Lei , Wen Yujie , Zhang Yixiao , Qin Tian , Wang Jia , Liu Tao , Xia Xifeng , Wu Di , Gong Xue-Qing , Tang Weiping , Ding Weiping , Liu Xi , Chen Liwei , Grey Clare P. , Peng Luming
Published: September 2022

Both atomic geometry and the influence of surroundings (e.g., exogenously coordinated water) are key issues for determining the chemical environment of oxide surfaces, whereas the latter is usually ignored and should be considered in future studies.
An ESIPT-based fluorescent probe for the detection of multiple analytes and a facile approach to discriminate between arsenate and pyrophosphate in water
Authors: Gadiyaram Srushti , Ghule Vikas D. , Ghosh Amrita , Jose D. Amilan
Published: September 2022

A simple ESIPT-based fluorescent probe for the detection of the multiple analytes such as chromium (Cr3+), arsenate (HAsO42−), and pyrophosphate (PPi, P2O74−) has been reported.
Bio-based poly(hexamethylene 2,5-furandicarboxylate-co-2,6-naphthalate) copolyesters: a study of thermal, mechanical, and gas-barrier properties
Authors: Mao Hsu-I , Yang Zhi-Yu , Chen Chin-Wen , Rwei Syang-Peng
Published: September 2022

The gas barrier properties of PHFN copolyesters were improved with the introduction of 2,6-naphthalene dicarboxylic acid, and the chain flexibility was increased to enhance processability when 1,6-hexanediol was introduced.
High-loading Fe1 sites on vanadium disulfides: a scalable and non-defect-stabilized single atom catalyst for electrochemical nitrogen reduction
Authors: Liu Yunxia , Fan Xing , Bian Wenyi , Yang Yingke , Huang Peipei , Hofer Werner A. , Huang Hui , Lin Haiping , Li Youyong , Lee Shuit-Tong
Published: September 2022

Atomically dispersed Fe atoms on a non-defective VS2 monolayer as a high loading, scalable and stable single atom catalyst for electrochemical nitrogen reduction.
Polarity-induced dual room-temperature phosphorescence involving the T2 states of pure organic phosphors
Authors: Zang Lixin , Shao Wenhao , Bolton Onas , Ansari Ramin , Yoon Seong Jun , Heo Jung-Moo , Kieffer John , Matzger Adam J. , Kim Jinsang
Published: September 2022

Polarity-induced room-temperature dual phosphorescence involving the T2 state of purely organic phosphors.
Did Changes to Adult Hearing Aid Pathways Due to COVID-19 Affect Patient Outcomes? A Service Evaluation
Authors: Duckworth Zoe , Beckman Adam , Heinrich Antje
Published: September 2022

Objective:

The objective of this study was to determine whether changes to adult hearing aid provision during COVID-19 affected patient outcomes or service efficiency.

Design:

A service evaluation compared three cohorts: patients who had hearing aid provision prior to the COVID-19 pandemic (the conventional pathway); patients who had hearing aid provision during the initial national lockdown (remote fittings); and patients who had hearing aid provision during the gradual reopening phase (a blended service with both face-to-face and remote service provision). Outcomes measured the effectiveness and efficiency of the service, using the Glasgow Hearing Aid Benefit/Difference Profiles (GHABP/DP) and number of follow-up appointments required. Results were assessed using descriptive statistics and error bars, separately for new and existing users.

Sample:

This study included 240 hearing aid users.

Results:

Remote fittings adversely impacted the effectiveness of provision for new hearing aid users with a reduction in all GHABP domains. While new users' benefit was equally as good for blended and conventional service provision, blended provision was less efficient and required more follow-up visits. For existing hearing aid users, no differences were seen in GHADP outcomes of different pathways and remote fittings increased service efficiency.

Conclusions:

Remote hearing aid fittings are less effective for new users than hearing aids fitted using standard face-to-face service provision or service provision using a blended model of remote and face-to-face care. Current pathways using a blended model of care are less efficient but equally effective for new hearing aid users compared with provision prior to COVID-19 and result in equivalent patient outcomes in terms of benefit.

Supplemental Material:

https://doi.org/10.23641/asha.21067585
CDFM: A cross‐domain few‐shot model for marine plankton classification
Authors: Guo Jin , Li Wengen , Guan Jihong , Gao Hang , Liu Baobo , Gong Lili
Published: September 2022

Marine plankton classification is important for monitoring marine biological populations and understanding marine ecosystems. However, it is difficult to obtain abundant annotated image data of marine plankton to train classification models of high quality. To classify marine plankton with a small number of image samples, a cross‐domain few‐shot learning model (CDFM) is proposed. First, CDFM learns knowledge from existing labelled images and then transfers the knowledge to new images. In this process, there is an issue of domain differences between the new images and the existing datasets due to differences in data acquisition time and locations. To address this issue, the authors pre‐train a model in the source domain and then use fine‐tuning to adapt it to the target domain. Second, the graph neural network is used as a meta‐learning module to learn a feature distance metric for marine plankton classification with limited samples. Extensive experiments on four marine plankton image datasets are conducted, including Kaggle Plankton, miniPPlankton, ZooScan and WHOI, and CDFM outperforms existing methods for marine plankton classification.
Optimal quantised bits for estimation over a capacity and power limited, lossy channel
Authors: Akumalla Venkatareddy , Khan Mohammed Zafar Ali
Published: September 2022

This letter considers the problem of estimating the state of a scalar dynamical system over a wireless channel that is lossy, capacity, and power limited. The limited power assumption, which is valid for most real problems, links the number of quantisation bits and packet error rate. As the number of quantisation bits increases, the quantisation noise decreases but the packet loss rate increases. It is shown that the estimation error variance (EEV) is minimised for a range of quantisation bits. Further, it is shown that operating beyond the optimal range sharply increases the EEV. Simulation results corroborating the analytical results are also presented.
Identifying and correcting the errors of vehicle trajectories from roadside millimetre‐wave radars
Authors: Lei Cailin , Zhao Cong , Ji Yuxiong , Shen Yu , Du Yuchuan
Published: September 2022

Millimetre‐wave (MMW) radars have been increasingly deployed along the roadside highways to collect vehicle trajectory data, which are valuable for traffic safety analyses and traffic control decisions. Nevertheless, possible errors of the trajectories resulting from roadside MMW radars have not been well documented. This study scrutinizes roadside MMW radar data and the concurrent video ground truth to identify five typical errors of vehicle trajectories, including different vehicles tagged with the same ID, different trajectories produced by the same vehicle, ghost vehicles, erroneous vehicle classification, and vehicle location drift. Data cleaning methods were developed to identify and correct these errors. The performance of the developed methods was evaluated empirically in a case study based on the data of five radars, which were installed at different locations along the highway and had different headings. The thresholds of the developed method were calibrated using one radar data and then applied to the data of the five radars. The results showed that the data qualities of all radars are greatly improved by the developed methods, demonstrating that the developed methods are generally applicable for cleaning vehicle trajectory data from roadside MMW radars.
Momentary finite element for elasticity 3D problems
Authors: Chekmarev Dmitry , Abu Dawwas Yasser
Published: September 2022

A description of a new 8-node finite element in the form of a hexahedron is given for solving elasticity 3D problems. This finite element has the following features. This is a linear approximation of functions in the element, one point of integration and taking into account the moments of forces in the element. The finite element is based on “rare mesh” FEM schemes—finite element schemes in the form of n-dimensional cubes (square, cube, etc.) with templates in the form of inscribed simplexes (triangle, tetrahedron, etc.). Among the rare mesh schemes, schemes in 3-dimensional and 7-dimensional spaces are successful, in which the simplex can be arranged symmetrically with respect to the center of the n-dimensional cube. The rare mesh FEM schemes have not the hourglass instability due to the fact that the template of the finite element operator has the form of a simplex. Compared to traditional linear finite elements in the form of a simplex, rare mesh schemes are more economical and converge better, since they do not have the effect of overestimated shear stiffness. Moment FEM schemes are constructed by rare mesh schemes higher dimensional projection, respectively, on a two-dimensional or three-dimensional finite element mesh. The resulting finite elements are close to the known polylinear elements and surpass them in efficiency. The schemes contain parameters that allow you to control the convergence of numerical solutions. The possibility of applying this approach to the construction of numerical schemes for solving other problems of mathematical physics is discussed.
Mathematical methods for predicting the durability of polymer composites under extreme conditions
Authors: Gusev Evgeny , Bakulin Vladimir , Chernykh Vera
Published: September 2022

The paper investigates the issue of promising ways to predict the durability of polymer composites under extreme conditions. A study of the possibility of predicting the durability of the material, based on the information obtained in the first years of operation. Based on themodern provisions of molecular kinetic theory (MKT), the issue ofmatching the defining parameters ofmathematical models calculated because of solving forecasting problems within the framework of the formulated variational formulation, considering the results of experimental measurements at the macro level, with the corresponding defining parameters of physical models describing molecular interactions at the microlevel, was investigated. The results of computational experiments are presented.
About the development of applied software for mechatronic systems of SLM technology
Authors: Tretiyakova Olga , Molotkov Andrey
Published: September 2022

The article describes the structure of the created software package for mechatronic systems that implements the technology of selective laser melting (SLM). One of the part of this software package is a software platform for solving machine vision tasks. Examples of several problems solved using the software platformare given. The solution to define the geometry and location of a metal sheet is considered in detail. The developed algorithm is used to solve the task of determining the geometry of the melted layer, the results of which will later be used for layer-by-layer reconstruction of the geometry of the manufactured part. The presented software platform was developed to implement analysis and control functions within the application software for implementing in SLM technology, however, as a result, the created software platform has received a wider range of applications.
La mémoire insupportable
Authors: Givord-Bartoli Augustin
Published: September 2022

Aujourd’hui, les troubles de la mémoire s’installent dans nos pratiques et notre questionnement. S’il nous paraît logique de lier ce phénomène à celui du vieillissement global de la population, une observation approfondie ouvre le champ d’une réflexion au-delà du seul sujet âgé. L’approche ici proposée part d’un trouble mémoriel déclaré sur le tard, pour mieux expliquer l’organisation de la mémoire depuis sa formation. Il s’agit de traiter les éléments manifestes en tant que signes structurels.

Ainsi, les désordres de la mémoire révèlent la trame inconsciente du sujet, et nous aident à penser son inscription psychique. Ceci au sein d’un monde où les technologies d’assistance à l’être humain, via l’informatique et la robotique principalement, sont en plein essor... au risque de croire en une science idéale, capable de biaiser tous nos insupportables.
Assessment of pediatric radiation doses in brain CT procedures
Authors: Bawazeer O. , Saleem R. , Alhazmi M. , Asiri N. , Mohammed T. , Alsaab A. , Algethami M. , Sedayo A. , Ajlouni A.
Published: September 2022

Background:To date in Saudi Arabia, a limited number of studies conducted to assess radiation doses received by pediatrics in computed tomography (CT) brain procedure. National diagnostic reference levels (NDRL) have been established for adults, but neither NDRL’s nor Local diagnostic reference levels (LDRL) have been established for pediatric patients. Objective: This study aimed to assess radiation doses experienced by pediatric patients in CT brain procedure, and derive LDRLs. Materials and methods: The values of three radiological indexes: volume CT dose index (CTDIvol) and dose-length product (DLP) were assessed. Then effective dose (ED) were estimated, and LDRLs are suggested for CT procedures based on data retrieved from 353 pediatric patients aged between 0 and 15 years old. LDRLs were estimated based on age and weight. Results: Built on 75 percent of the median distribution of the CTDIvol and DLP values, weight assemblage LDRL values ranged from 12.29 to 28.72 mGy and from 173.32 to 565.38 mGy.cm, respectively, whereas age assemblage LDRL values ranged from 11.76 to 25.07 mGy and from 147.04 to 479.23 mGy.cm, respectively. Conclusion: This study derived the typical CTDIvol, DLP, and ED received by pediatric patient during CT brain procedure in Saudi Arabia. Then, LDRLs were proposed based on age and weight for pediatric patients aged between 0 to 15 years old.
Face validity of a virtual reality simulation platform to improve competency in endoscopy: a prospective observational cohort study
Authors: Eley Catherine , Hawkes Neil D , Egan Richard J , Robinson David B , Brown Chris , Murray Sam , Siau Keith , Lewis Wyn
Published: September 2022

Background and study aims Virtual reality endoscopic simulation training has the potential to expedite competency development in novice trainees. However, simulation platforms must be realistic and confer face validity. This study aimed to determine the face validity of high-fidelity virtual reality simulation (EndoSim, Surgical Science, Gothenburg), and establish benchmark metrics to guide the development of a Simulation Pathway to Improve Competency in Endoscopy (SPICE).

Methods A pilot cohort of four experts rated simulated exercises (Likert scale score 1–5) and following iterative development, 10 experts completed 13 simulator-based endoscopy exercises amounting to 859 total metric values.

Results Expert metric performance demonstrated equivalence (P = 0.992). In contrast, face validity of each exercise varied among experts (median 4 (interquartile range [IQR] 3–5), P < 0.003) with Mucosal Examination receiving the highest scores (median 5 [IQR 4.5–5], P = 1.000) and Loop Management and Intubation exercises receiving the lowest scores (median 3 [IQR 1–3], P < 0.001, P = 0.004), respectively. The provisional validated SPICE comprised 13 exercises with pass marks and allowance buffers defined by median and IQR expert performance.

Conclusions EndoSim Face Validity was very good related to early scope handling skills, but more advanced competencies and translation of acquired clinical skills require further research within an established training program. The existing training deficit with superadded adverse effects of the COVID pandemic make this initiative an urgent priority.
Underwater endoscopic submucosal dissection and hybrid endoscopic submucosal dissection as rescue therapy in difficult colorectal cases
Authors: Cecinato Paolo , Lucarini Matteo , Campanale Chiara , Azzolini Francesco , Bassi Fabio , Sassatelli Romano
Published: September 2022

Background and study aims Colorectal endoscopic submucosal dissection (ESD) is still not widely used due to its technical difficulty and the risk of complications. Rescue therapies such as hybrid ESD (H-ESD) have been proposed for very difficult cases, as has underwater ESD (U-ESD). This study evaluated the safety and efficacy of H-ESD and U-ESD in difficult cases.

Patients and methods The hospital charts of consecutive patients referred for colorectal ESD between January 2014 and February 2021 because they were considered difficult cases were retrospectively analyzed. The primary outcome of the study was en bloc resection rate; secondary outcomes were the rate of complete resection, procedure speed, and incidence of adverse events (AEs).

Results Fifty-nine colorectal neoplasms were considered, 22 of which were removed by U-ESD and 37 by H-ESD. The en bloc resection rate in the U-ESD group was 100 %, while it was 59.5 % in the H-ESD group. Dissection speed was 17.7mm2/min in the U-ESD group and 8.3 mm2/min in the H-ESD group. The AE rate was low in the U-ESD group and moderately high during H-ESD (5 % and 21.6 %, respectively; and perforation rate 0 % and 10.8 %, respectively). Larger lesions were treated with U-ESD, while more fibrotic ones were treated with H-ESD.

Conclusions U-ESD and H-ESD are both effective and safe techniques in difficult colorectal situations. U-ESD is particularly effective and fast for large lesions when it is not possible to obtain comfortable knife position, while H-ESD is more suitable for very fibrotic lesions.
Educational interventions to improve ergonomics in gastrointestinal endoscopy: a systematic review
Authors: Shergill Amandeep K. , Grover Samir C. , Scaffidi Michael A. , Gimpaya Nikko , Fecso Andras B. , Khan Rishad , Li Juana , Bansal Rishi , Torabi Nazi
Published: September 2022

Background and study aims Endoscopists are at high risk of musculoskeletal pain and injuries (MSPI). Recently, ergonomics has emerged as an area of interest to reduce and prevent the incidence of MSPI in endoscopy. The aim of this systematic review was to determine educational interventions using ergonomic strategies that target reduction of endoscopist MSPI from gastrointestinal endoscopy.

Methods In December 2020, we conducted a systematic search in MEDLINE, EMBASE, PsycINFO, Web of Science, Scopus, the Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews for articles published from inception to December 16, 2020. Studies were included if they investigated educational interventions aimed at changing knowledge and/or behaviors related to ergonomics in gastrointestinal endoscopy. After screening and full-text review, we extracted data on study design, participants, type of training, and assessment of primary outcomes. We evaluated study quality with the Medical Education Research Study Quality Instrument (MERSQI).

Results Of the initial 575 records identified in the search, five met inclusion criteria for qualitative synthesis. We found that most studies (n = 4/5, 80 %) were single-arm interventional studies that were conducted in simulated and/or clinical settings. The most common types of interventions were didactic sessions and/or videos (n = 4/5, 80%). Two (40 %) studies used both standardized assessment studies and formal statistical analyses. The mean MERSQI score was 9.7.

Conclusions There is emerging literature demonstrating the effectiveness of interventions to improve ergonomics in gastrointestinal endoscopy.
Angiosarcoma on Top of a Meningioma Mimicking a Transosseous Meningioma: an Interdisciplinary Point of View
Authors: Kohl Jana , König Rebecca E , Kraus Armin , Mawrin Christian , Paukisch Harald , Stein Klaus-Peter , Rashidi Ali , Luchtmann Michael , Sandalcioglu I Erol , Lilla Nadine
Published: September 2022

Cutaneous angiosarcoma is a rare type of sarcoma with poor prognosis. Meningioma is the most frequent benign intracranial tumor. Despite the fact that meningiomas are mostly benign, bone and skin can be infiltrated. We report the rare case of an angiosarcoma on top of a meningioma with hyperostosis at exactly the same location mimicking a transosseous growth of a meningioma. An 84-year-old man presented with progressive swelling and ulcerous lesion of the forehead. The patient underwent surgery in an interdisciplinary setting together with a plastic surgeon, including resection of the intracranial tumor and infiltrated bone and skin. To the best of our knowledge, this is the only reported case of a meningioma and angiosarcoma in direct neighborhood. A preoperative biopsy of the skin tumor would have led initially to the correct diagnosis of an angiosarcoma and would have allowed a better planning of the operation and extent of resection.
Imaging of Structural Abnormalities of the Sacrum: The Old Faithful and Newly Emerging Techniques
Authors: Vereecke Elke , Herregods Nele , Morbée Lieve , Laloo Frederiek , Chen Min , Jans Lennart
Published: September 2022

The sacrum and sacroiliac joints pose a long-standing challenge for adequate imaging because of their complex anatomical form, oblique orientation, and posterior location in the pelvis, making them subject to superimposition. The sacrum and sacroiliac joints are composed of multiple diverse tissues, further complicating their imaging. Varying imaging techniques are suited to evaluate the sacrum, each with its specific clinical indications, benefits, and drawbacks. New techniques continue to be developed and validated, such as dual-energy computed tomography (CT) and new magnetic resonance imaging (MRI) sequences, for example susceptibility-weighted imaging. Ongoing development of artificial intelligence, such as algorithms allowing reconstruction of MRI-based synthetic CT images, promises even more clinical imaging options.
Using phylogenetics to infer HIV-1 transmission direction between known transmission pairs
Authors: Villabona-Arenas Christian Julian , Hué Stéphane , Baxter James A. C. , Hall Matthew , Lythgoe Katrina A. , Bradley John , Atkins Katherine E.
Published: September 2022

Inferring the transmission direction between linked individuals living with HIV provides unparalleled power to understand the epidemiology that determines transmission. Phylogenetic ancestral-state reconstruction approaches infer the transmission direction by identifying the individual in whom the most recent common ancestor of the virus populations originated. While these methods vary in accuracy, it is unclear why. To evaluate the performance of phylogenetic ancestral-state reconstruction to determine the transmission direction of HIV-1 infection, we inferred the transmission direction for 112 transmission pairs where transmission direction and detailed additional information were available. We then fit a statistical model to evaluate the extent to which epidemiological, sampling, genetic, and phylogenetic factors influenced the outcome of the inference. Finally, we repeated the analysis under real-life conditions with only routinely available data. We found that whether ancestral-state reconstruction correctly infers the transmission direction depends principally on the phylogeny's topology. For example, under real-life conditions, the probability of identifying the correct transmission direction increases from 32%—when a monophyletic–monophyletic or paraphyletic–polyphyletic tree topology is observed and when the tip closest to the root does not agree with the state at the root—to 93% when a paraphyletic–monophyletic topology is observed and when the tip closest to the root agrees with the root state. Our results suggest that documenting larger differences in relative intrahost diversity increases our confidence in the transmission direction inference of linked pairs for population-level studies of HIV. These findings provide a practical starting point to determine our confidence in transmission direction inference from ancestral-state reconstruction.
Emergence of a random field at the yielding transition of a mean-field elasto-plastic model
Authors: Rossi Saverio , Tarjus Gilles
Published: September 2022

We study the mean-field limit of an elasto-plastic model introduced to describe the yielding transition of athermally and quasi-statically sheared amorphous solids. We focus on the sample-to-sample fluctuations, which we characterize analytically, and investigate in detail the analogy with the athermally driven random-field Ising model. We stress that the random field at the yielding transition is an emerging disorder and we investigate the various factors that determine its strength.
Community detection based on competitive walking network embedding method
Authors: Xue Kun , Han Xiaoxia , Wu Jinde , Shen Yadi , Xu Xinying , Xie Gang
Published: September 2022

Currently, much of the information of the real world is network-structured, and extracting hidden information from network-structured data helps to understand the corresponding systems, but can also be a challenging problem. In recent years, network embedding has been an effective way to extract network information, which represents nodes in complex networks as low-dimensional space vectors, while preserving the properties of the network. Community attributes are an important property of networks, and in most network embedding algorithms, the community structure is usually ignored or cannot be explicitly preserved. In this paper, we propose a new network embedding framework that explicitly considers community structure feature extraction. The framework, called competitive walking network embedding (CWNE), extracts sample sequences by competitive walking and obtains node representation vectors by skip-gram training. Competitive walking allows the extracted sample sequences to be concentrated within the same community, effectively preserving the community structure features of the network. The results of testing the proposed method on artificial and real-world networks show that our model is more effective in detecting community structure in networks. In addition, visualization experiments show that the results of CWNE show that nodes from the same community are more tightly distributed in low-dimensional space.
Microstructural evolution in S31042 heat-resistant steel after service and the effect on hardness
Authors: Jin Xiao , Xia Xianxi , Zhu Baoyin , Zhao Yanfen , Duan Peng , Liang Jun , Du Jinfeng , Zhou Chao , Zhang Guodong
Published: September 2022

The ultra-supercritical power generation technology with high energy efficiency and low emissions is one of the important ways to solve the current increasingly prominent energy problems in the context of international development requirements for carbon neutrality and the increasingly prominent energy shortage. Because of its excellent resistance to high temperature corrosion and organizational stability, S31042 is commonly employed in the most severe working environment of ultra-supercritical units. Due to its great resistance to high-temperature corrosion and organizational stability, S31042 is commonly employed in the most demanding components of ultra-supercritical units such as high-temperature reheaters and high-temperature superheaters. Various characterisation approaches were employed in this research to reflect the microstructure of S31042 heat-resistant steel in service under various time length conditions, and the hardness of S31042 heat-resistant steel was assessed under the corresponding service conditions. The results showed that the hardness of S31042 increased significantly with increasing service time, from around 160 Hv at the time of non-service to nearly 220 Hv after 75360 hours of service. The continuous distribution of uniformly sized M23C6 phase on the grain boundaries of S31042 developed toward grain coarsening after service, but the precipitation strengthening effect produced by the nanoscale secondary NbCrN phase appearing in the grains was the main reason for the increase of the hardness value of S31042, according to the microstructure of the material.
Analysis of the effect of bending rigidity on Gaussian Curvature for clamped and simply supported thin circular plates
Authors: Huang Pengfei , Song Yanping , Su Guanlong
Published: September 2022

Negative Gaussian curvature in deformed surface subjected to concentrated loads is a key weakening factor on the surface accuracy of umbrella antennas. The negative impacts can be mitigated by increasing the bending rigidity of the reflector surface. Thus, firstly, this paper is concerned with the effect of bending rigidity on Gaussian curvature based on the analysis of bending circular thin plate with large deflection. Exact expressions of Gaussian curvature for deformed circular thin plates are derived using the analytical solution of the von-Karman plate equation and the properties of positive and negative for Gaussian curvature is investigated. After solving the zeroes of Gaussian curvature using the Newton iteration method, Gaussian curvature distribution of the deformed surface is obtained.
Heat Transfer Modelling of Friction Stir Lap Welding of PP Plastics and 6061 Aluminium Alloy
Authors: Guo Hua , Zhou Jian , Sun Haijie , Cao Bowen , Yu Wangyang , Li Hongjun
Published: September 2022

Structures with dissimilar materials can make full use of the advantages of each material. However the welding of the aluminum alloy plate and plastic plate are difficult due to high difference in melting point. The friction stir lap welding method is selected in this paper. The numerical model was built to study the heat transfer behavior inside the plates, as the temperature plays an important role in determine the weld quality. The model was validated through experimentally measured temperature results. The influence of welding process parameters such as welding speed, tool rotating speed and downward feed was analyzed. It was found that under the welding speed of 100r/min and downward feed of 0.3mm/s, sound weld was produced.
Strength Analysis and Research of one Touring Car Frame
Authors: Liu Meng , Liu Jing
Published: September 2022

In order to evaluate the static strength and reliability of touring car frame structure, based on the finite element theory and the simplified model, this paper establishes the finite element model to numerically simulate the static strength reliability of the structure under four common working conditions of bending, torsion, braking and turning. It analyses its maximum stress under the limit load, and finds out the weak area of the structure, The corresponding structural optimization scheme is proposed, which largely replaces the physical prototype verification process in the transmission design, greatly reduces the product R & D cycle, and provides theoretical support for the structural optimization of the whole vehicle.
Preparation of flexible titanium dioxide nanofiber membrane and its degradation of malachite green dye
Authors: Guo Bin , Liu Xiao-Yan , Liu Yi-Tao
Published: September 2022

With the continuous development of science and technology, people begin to pay attention to environmental protection. At present, there are many fields causing environmental pollution, among which printing and dyeing wastewater has become the most difficult to degrade in our daily life due to the complexity and instability of organic substances in its water. The seriousness of printing and dyeing wastewater pollution has a great impact on our living ecological environment. As a typical material in semiconductors, titanium dioxide has the advantages of low price, strong compatibility, non toxicity, self-cleaning and stable physical and chemical properties. These advantages determine that titanium dioxide has absolute advantages and deeper potential in the field of photocatalysis. There are a variety of types and forms of titanium dioxide, including titanium dioxide film, powder, particle, fiber and so on. The flexible titanium dioxide nanofiber membrane prepared by electrospinning has the characteristics of high specific surface, large pore size and high transmittance. Flexible titanium dioxide nanofiber membrane is more available and recyclable and can avoid secondary pollution as well. Therefore, the preparation and selection of reasonable photocatalytic materials is also a key step in the field of photocatalytic technology.
Heat-resistant poly (arylene ether nitriles) separator for high-safety lithium batteries via dual-functional modification
Authors: Lin Guo , Liu Chenchen , Bai Zhongxiang , Liu Shuning , Han Mangui , Huang Yumin , Liu Xiaobo
Published: September 2022

Herein, we report a dual-modified organic-inorganic separator as an alternative to polyolefin commercial separator for lithium metal batteries. This composite separator exhibits high thermal stability properties due to the use of an engineering plastic matrix of poly (arylene ether nitriles) (PEN). The dual hydrophilic modification strategy also allows the separator to have a high ionic conductivity and a low interfacial impedance. With this new separator, lithium-metal batteries have high charge/discharge capacity and high-rate performance. Moreover, Li/Li symmetric cells display long-term stability and phenomenon of suppressing the lithium dendrite in lithium-metal batteries.
Incident-angle dependence of deformation characteristics of aluminum surface under low-energy xenon-ion impact
Authors: Zhang Cheng , Zhou Jiang , Xie Wenkai
Published: September 2022

Ion thruster is a revolution technology with potential applications in space mission but the thruster’s operation lifetime is limited by the sputtering from thruster components. In this work, molecular dynamic simulations are performed to explore the dependence of deformation characteristics of an aluminum surface on incident angle and kinetic energy under low-energy xenon-ion impact. The fraction of non-12-coordinated atoms is used to quantitatively characterize the microstructural evolution and defect density levels. It is found that defect density level has a linear relation with incident energy, and there exists a critical incident angle around 20°, at which the aluminum surface has the maximum defect density level. In addition, a collision model is developed to theoretically reveal the physical mechanisms behind the dependence. Our findings may helpful in developing long endurance electric propulsion devices for practical applications.
Dielectric properties of polyarylene ether nitrile composites based on modified boron nitride
Authors: Liu Shuning , Liu Chenchen , Feng Xiaofang , Lin Guo , Bai Zhongxiang , Liu Xiaobo
Published: September 2022

Polyarylene ether nitrile (PEN) is a new type of super engineering polymer with excellent high-temperature resistance, radiation resistance, good electrical insulation, and mechanical properties. In this work, boron nitride (BN) and copper phthalocyanine (CuPc) hybrids were integrated as fillers, which were further dispersed into PEN matrix by solution casting method to obtain a series of PEN composite films. The successful preparation of hybrid fillers was proved by means of X-ray photoelectron spectroscopy and scanning electron microscopy. The test results of the dielectric properties of the composite films show that the CuPc-BN/PEN films exhibit good dielectric properties. When the mass fraction of filler reaches 10 wt%, the dielectric constant of the PEN composite film increases by 17%. This study shows that the composites composed of modified BN and PEN has excellent dielectric properties and has great application potential in heat-resistance thin-film capacitors.
Analysis of Chemical Reaction C6H12N6 + KCLO4 + Mg + SrSO4 in Solid-phase Oscillating Combustion
Authors: Wang Xiaoxia , Gao Xing
Published: September 2022

In this paper, aiming at the chemical reaction system of solid-phase oscillating combustion, the basic dynamic behavior of laser system in terms of bifurcation diagram, Lyapunov exponent and complexity C0 is analyzed by using Matlab software, and the chaotic characteristics and sensitivity to parameters of the chemical reaction system of solid-phase oscillating combustion are expounded.
Thermal Stress Analysis for Carbon/Carbon Material Throat Lining Based on Finite Element Analysis
Authors: Xiong Xuefeng , Li Li , Li Hong , Zan Peng
Published: September 2022

As a key part of the solid rocket motor, the nozzle always withstands a series of problems such as high-temperature, high-pressure, and chemical erosion and faces more severer environmental challenges. So its Stability plays a vital role in the normal operation of the engine. This paper takes the engine nozzle throat lining as the research object, uses the ANSYS to establish a carbon/carbon composite throat lining model in the ACP module, and analyzes the stress and displacement of the throat lining in a high-temperature and high-pressure environment. The experimental results show that under the high-temperature condition of 3500°C, the maximum stress value is 2734.8MPa, and more than 96% of the area is below 1000MPa, lower than the prescribed stress threshold. The superiority in the performance of the throat lining prepared for carbon/carbon materials is verified, and the structural integrity of the throat lining can still be guaranteed under high-temperature conditions.
Research on deformation coordination of composite metal gears in the process of cold extrusion
Authors: Wang Tao , Zhang Yishuai , Sun Hongxing , Wang ZhengBing , Liu Hua
Published: September 2022

In order to realize lightweight manufacturing of gear parts, the cold extrusion forming process of steel-aluminum composite metal gears was studied. Using numerical simulation software Deform, the effects of five steel rings with different thicknesses on forming pressure and shapes of formed forgings were compared. The simulation results showed that final forming force of the gear was smaller and the radial deformation degree of steel ring was larger when using thinner steel ring. This radial deformation degree was characterized by height difference between the convex and the concave in steel-aluminum bonding position, and great deformation presented as obvious bimetal occlusion. The physical experiment verified numerical simulation results, and meanwhile found that the thickness of steel sleeve had an important effect on bonding tightness of steel-aluminum contact surface of formed part and the composite gear formed by thin steel ring had a gap at tooth tip between steel and aluminum. Comprehensive analysis suggested the ratio of outer diameter to inner diameter (R0/Ri) of steel sleeve reflected different deformation regularity. Consequently, the thick-walled axial compression model was used to analyze forming process of steel sleeve with high R0/Ri ratio, and the thin-walled cylindrical shell model was used to analyze forming process of steel sleeve with low R0/Ri ratio. The axial compression of thin cylindrical shell produced local buckling deformation, which led to the appearance of gaps in steel-aluminum bonding position. In order to avoid gaps in bimetal contact surface, the influence of steel ring thickness on deformation coordination of two metals should be fully considered in cold extrusion of steel-aluminum composite metal gear.
Analysis of Stiffness Performance of one Insulated Carriage
Authors: Jing Liu , Meng Liu
Published: September 2022

Based on the finite element theory, the stiffness of an insulated carriage is analysed in this paper. Different from the traditional car, the thermal insulation car puts forward higher requirements for the bending stiffness and torsional stiffness under static and full load conditions. Through the finite element stiffness analysis, the stiffness of the whole frame can be preliminarily determined. The results show that under the bending condition, the tail deformation of the carriage is large and the tail stiffness is insufficient. In the follow-up, it is necessary to improve the tail bending stiffness of the carriage through structural optimization.
Exfoliation of hexagonal boron nitride nanosheets assisted with covalent organic frameworks by ball-milling
Authors: Yan Yunrui
Published: September 2022

Boron nitride nanosheets have superior chemical and physical properties. However, there are many problems in the preparation of hexagonal boron nitride nanosheets, and an effective exfoliation method is still lacking. To solve this problem, this paper intends to obtain boron nitride nanosheets by ball milling using TpPa from COFs material as a ball milling aid, and to investigate various factors affecting the ball milling effect. The h-BN obtained by using some other polymer materials such as starch and pvp as ball milling aids were compared with the h-BN peeled by using COFs materials as ball milling aids, and the results showed that the peeling effect of using TpPa as ball milling aids was not satisfactory because the structure of COFs materials was too stable. This paper also further conducted ball milling experiments on a variety of dry auxiliaries and compared them according to the ball milling effect The strength, friction, softening point and hardness were analyzed by machine learning. The analysis revealed that these aspects affect the cross-sectional area, thickness and aspect ratio of h-BN nanosheets. To obtain good h-BN nanosheets, the main conclusions of this paper are as follows: For the cross-sectional area of h-BNNS: the bond strength, friction, hardness and softening point of the ball milling agents have a strong influence on it and are positively correlated with it, while the friction and softening point of the ball milling agents are negatively correlated with it. For the thickness of h-BNNS: the bond strength and decomposition point of ball abrasives have influence on it, but not much, while hardness, softening point and contact angle have more influence on it, and hardness and contact angle are positively correlated with it, and softening point is negatively correlated with it. For the aspect ratio of h-BNNS: the hardness, softening point and contact angle of the ball abrasive have a greater effect on it, while the softening point has the greatest effect on it with a positive trend and the hardness and contact angle with a negative trend.
Study on dynamic characteristics of flexible feed system by mechanical parameters
Authors: Luo Fei , Chen Hongsheng , Wei Nan
Published: September 2022

The dynamic characteristics of CNC feed system are determined by the dynamic characteristics of mechanical drive and control parameters. The dynamic characteristics of transmission link are closely related to the mechanical characteristic parameters. The designer must find the matching control parameters by analyzing the law of mechanical characteristic parameters and dynamic characteristics. In this paper, the relationship between inertia ratio, resonant frequency and velocity loop control gain is analyzed by using the established three-inertia system model, and the parameters are input into the system model for simulation. It provides a method for the designers of CNC machine tools to adjust the internal control parameters, which has important theoretical and practical value.
Research on Reliability Analysis of Axial-Symmetric Vectoring Exhaust Nozzle Based on Parametric Modeling
Authors: Du Quhu , Li Jia , Xie Liyang , Fu Xingming , Wang Yi
Published: September 2022

According to the motion characteristics of Axial-Symmetric Vectoring Exhaust Nozzle (AVEN), its motion process is divided into the convergence deflection of the adjusting piece of the A8 sub-mechanism and the expansion deflection of the adjusting piece of the A9 sub-mechanism. Taking the A9 sub-mechanism as an example, proposing a method based on Solidworks-Abaqus-Adams multi-software platform to establish a rigid-flexible coupled parametric model and run the motion simulation model to analyze the influence of different factors on the motion accuracy of the mechanism. Basing on the Monte Carlo sampling algorithm to design a program of automatic sampling solution that is separated from Adams platform. Under the condition of meeting certain accuracy requirements, the degree of automation in the sampling process is greatly improved. Finally, the probability distribution of the performance parameters of the A9 mechanism is obtained, and its reliability is calculated. The research results show that when considering various influencing factors, the motion accuracy of the mechanism will have corresponding deviations, which will have a certain impact on the reliability of the mechanism.
Random Vibration Analysis of L-type Electric Luggage Conveyor Vehicle Frame
Authors: Gao Jianshu , Meng Xiangsen
Published: September 2022

In order to verify the rationality of the designed L-type electric luggage conveyor vehicle frame structure, this paper imports the frame structure of the designed L-type conveyor vehicle into ANSYS Workbench software, conducts modal analysis, and evaluates the performance of the frame by analyzing the inherent frequency and vibration pattern, then uses Matlab to build the simulation model of the airfield pavement, calculates the power spectrum density, and the dynamic response and stress solution of the conveyor vehicle under specific operating conditions, and conducts random vibration The dynamic response and stress solution of the frame under the specific operating conditions are obtained. The results show that the frame of the L-type electric luggage conveyor is less excited by the road surface during the driving process, which will not cause large damage to the structure and is reasonably designed in terms of vibration characteristics.