bluuebunny/crossref_metadata_2025 huggingface dataset:
Speech-Language Pathologists' Perceptions of Language and Literacy Instruction for Pre-K Children With Developmental Language Disorder
Authors: Pfeiffer Danika L. , Feuerstein Julie , Landa Rebecca J.
Published: September 2023

Purpose:

Speech-language pathologists (SLPs) have multiple roles and responsibilities related to language and literacy instruction in schools. The purpose of this exploratory, qualitative study was to analyze school-based SLPs' perceptions related to effective language and early literacy instruction for pre-K children with developmental language disorder (DLD). The goal of this study was to inform development of a new language and early literacy professional development program for inclusive pre-K teachers.

Method:

Eight school-based SLPs participated in a 1-hr virtual focus group conducted via Zoom recording technology. The researchers used a conventional content analysis approach to analyze the focus group data and identify themes from the discussion.

Results:

The researchers developed two themes: (a) SLPs identified repeated exposure to books, peer interaction, and teaching vocabulary with visual supports and props as key elements of language and literacy instruction that can be integrated into a variety of contexts, and (b) SLPs want more time with parents and teachers to support their book reading and model specific language strategies.

Conclusions:

SLPs identified several instructional practices inclusive pre-K teachers could be taught to use during professional development programs to support the emergent literacy development of children with DLD. They also discussed the need for ongoing collaboration between SLPs, caregivers, and teachers to maximize children's early language and literacy experiences. Future research should explore the impact of partnerships with caregivers and teachers on children's language and literacy outcomes.
An intermediate frequency reconfigurable bandpass noise‐shaping SAR ADC for IoT and mobile application
Authors: Kim Jonghyun , Oh Younggyun , Chae Hyungil
Published: September 2023

This letter proposes a reconfigurable bandpass noise‐shaping successive approximation register analog‐to‐digital converter (ADC) with a cascade of integrators with feedforward (CIFF) structure. Unlike conventional CIFF structures that use a passive feedforward path, the new design incorporates an amplifier within the filter, providing effective bandpass noise transfer function regardless of passband location, and facilitating the use of a unity gain 2‐input comparator for low noise and high stability. The loop filter includes amplification by a low power Gm‐R amplifier and two‐step charge sharing. The proposed ADC supports three different intermediate frequencies (IFs), and 12‐bit resolution is achieved for all IFs in a 28‐nm complementary metal‐oxide‐semiconductor (CMOS) process.
Statistical properties of effective elastic moduli of random cubic polycrystals
Authors: Sheng Ningyue , Khazaie Shahram , Chevreuil Mathilde , Fréour Sylvain
Published: September 2023

The homogenized elastic properties of polycrystals depend on the grain morphology and crystallographic orientations. For simplification purposes, the orientations of the grains are usually considered three independent Euler angles. However, experimental investigations reveal spatial correlations in these angles. The Karhunen–Loève expansion is used to generate random fields of Euler angles having exponential kernel functions with varying correlation lengths. The effective elastic moduli for numerically generated statistically equiaxed cubic polycrystals are estimated via the classical Eshelby–Kröner Self-Consistent homogenization model. The influence of the correlation lengths of the orientations’ random fields on the statistical properties of the effective elastic moduli has been investigated. Our results show that spatially correlated Euler angles could increase the variability of the homogenized elastic properties compared to the ones having uncorrelated Euler angles. Nevertheless, using independent random variables for Euler angles remains valid when correlation lengths are close to the average grain size.
Observational evidence of thermospheric wind and composition changes and the resulting ionospheric disturbances in the European sector during extreme geomagnetic storms
Authors: Kim Jeongheon , Kwak Young-Sil , Lee Changsup , Lee Jaewook , Kam Hosik , Yang Tae-Yong , Jee Geonhwa , Kim YongHa
Published: September 2023

On November 1st and 2nd, 2021, four Halo coronal mass ejections were ejected from the Sun, releasing billions of tons of high-energy particles into interplanetary space. These were directed towards the Earth and reached our planet on November 3rd and 4th, 2021, generating the first G3-level extreme geomagnetic storm since the beginning of the 25th solar cycle. In this study, we investigate the thermospheric and ionospheric responses in the European sector to a G3-level storm using various observational data from Fabry-Perot interferometer, Ionospheric Connection Explorer/Michelson Interferometer for Global High-resolution Thermospheric Imaging (ICON/MIGHTI), and Thermosphere Ionosphere Mesosphere Energetics and Dynamics/Global Ultraviolet Imager (TIMED/GUVI). The results show positive ionospheric storms in the middle and low latitudes of Europe which may be associated with the equatorward and westward neutral winds induced by heating in the polar region. In contrast, negative storms were detected at high latitudes in association with the increase in thermospheric density (upwelling). These two antithetical responses were confirmed by using European ionosonde and total electron contents (TEC) observation chains distributed over a wide range of latitudes. Finally, we, for the first time, attempt to identify the imaginary boundary line between the two responses.
Chronic non-bacterial osteomyelitis (CNO) in childhood and adolescence – a disease with many faces
Authors: Steinborn Marc , Huf Veronika
Published: September 2023

Background Chronic non-bacterial osteomyelitis (CNO) is a chronic inflammatory skeletal disease that affects particularly children and adolescents and is often diagnosed with a delay. With whole-body MRI, early diagnosis of this disease is possible in many cases. Since children and adolescents frequently present with non-specific complaints for outpatient radiological diagnosis, every radiologist should have basic knowledge of this complex clinical picture.

Materials In this review the basics and current findings regarding the disease are discussed. Unusual courses are also presented.

Results and Conclusion With knowledge of the radiographic and MR tomographic characteristics of the mostly multifocal bone lesions, the diagnosis of CNO can be reliably made in many cases. In particular, the early use of whole-body MRI plays an important role. Thus, therapeutic delays and resulting complications and the number of unnecessary biopsies for diagnosis can be reduced.

Keywords:
Translation and Pilot Validation of Hindi, Marathi, and Bangla Translation of Quality-of-Life EORTC Radiation Proctitis Module (PRT-20) for Routine Clinical Use
Authors: Krishnamurthy Revathy , Krishnatry Rahul , Rane Devankshi , Pawar Purva , Chakraborty Debanjan , Gaikwad Utpal , Ghosh Suman , Siddiqui Aasma , Datta Debanjali , Anup Akanksha , Das Sayan , Gudi Shivakumar , Engineer Reena
Published: September 2023

The aim of this study was to translate and validate the European Organization for Research and Treatment for Cancer (EORTC) “Radiation Proctitis” (PRT-20) module in Hindi, Marathi, and Bangla languages. The EORTC PRT-20 was translated into Hindi, Marathi, and Bangla using EORTC guidelines. Two separate translators first translated the original questionnaire into the three regional languages, following which a reconciled forward translation was compiled. This reconciled version in each language was then back-translated into English by two other translators. This back-translated version was then compared with the original the EORTC questionnaire for correctness, and the preliminary questionnaires were formed in all three languages. The EORTC translation unit approved the questionnaires. The preliminary questionnaires were administered to 30 patients (10 for each language) diagnosed with rectal or anal canal cancer who had received pelvic radiotherapy and were at risk of developing PRT. None of the patients had seen the questionnaire before. After filling out the questionnaire, each patient was interviewed for difficulty in answering, confusion, understanding, or if any of the questions were upsetting and if patients would have asked the question differently. No changes were suggested for Marathi and Bangla translations. Two modifications were suggested in the Hindi translation, which was then retested in five patients and finalized. All the suggestions were incorporated into the preliminary questionnaires, which were sent back to the EORTC for final approval. After reviewing the entire report of pilot testing for the translated quality-of-life questionaire-PRT-20 in three languages, it was approved by the EORTC translation unit. The translated questionnaires were reliable, with Cronbach α values of 0.767, 0.799, and 0.898 for Hindi, Marathi, and Bangla, respectively. The Hindi, Marathi, and Bangla translations of PRT-20 have been approved by the EORTC and can be used in routine clinical practice.
Design, Synthesis, and Neuroprotective Effects of Novel Cinnamamide-Piperidine and Piperazine Derivatives
Authors: Li Jia-Yi , Peng Xin-Yan , Huang Yi-Lei , Jiang Ling , Li Jian-Qi , Yang Xue-Zhi , Zhang Qing-Wei
Published: September 2023

In our previous studies, Fenazinel has shown good neuroprotective effects; however, when Fenazinel entered phase 1 clinical trials, it was associated with certain side effects. This study aimed to explore novel neuroprotective agents with higher potency and lower toxicity. Evidence suggested that cinnamic acid and its analogs may serve as promising lead compounds for stroke treatment. In this study, a series of Fenazinel derivatives were first synthesized with potential neuroprotective effects with fragments including cinnamic acid and its analogs as key functional groups. The methyl thiazolyl tetrazolium assay was performed to assess the neuroprotective effects of the compounds in glutamate-induced neurotoxicity in SH-SY5Y cells. The hERG binding assay was conducted to assess drug-induced QT prolongation or other cardiotoxicity. The neuroprotective activity of the most potent compound in vivo was tested through the survival time of mice under the hypoxic condition and a middle cerebral artery occlusion model. Our data suggested that among those derivatives, compound 9d exhibited potent neuroprotective activity in vitro comparable to Fenazinel at the test concentrations. Significantly, 9d exhibited weak hERG inhibitory activity, showing moderate activities in both hypoxia-tolerant and MCAO models in vivo. Given the above, 9d has the potential for the treatment of stroke and could be considered a lead neuroprotective agent for further development.
Impact of Human Papillomavirus on Survival, Inflammation, and Immune Function in Patients with Cervical Cancer Undergoing Surgery
Authors: Hua Hui , Lei Xiaoyong , Yu Jia , Zhang Xinxin
Published: September 2023

No studies have examined the impact of human papillomavirus (HPV)-16 and HPV-18 on survival, inflammation biomarkers, and immune function in early-stage cervical cancer patients undergoing surgery. Patients diagnosed with early-stage cervical cancer were screened for high-risk HPV prior to surgery. The influence of HPV infection on survival, inflammatory markers, and immune function was investigated. Findings revealed that patients in the HPV-18 positive subgroup exhibited poorer disease-free survival (DFS) and elevated levels of interleukin-6 and C-reactive protein, along with decreased CD4+ T cells compared to patients who tested negative for HPV-18. Notably, early-stage cervical cancer patients with HPV-18 infection experienced worse DFS, heightened inflammatory markers, and compromised immune function.
Quantum-chemical investigation of the superoxide radical scavenging by graphene oxide surface
Authors: Demianenko Eugeniy , Sencha-Hlevatska Kateryna , Sementsov Yurii , Kartel Mykola
Published: September 2023

The current investigation presents the results of quantum-chemical calculations (using B3LYP/6–31G(d,p) and MP2/6–31G(d,p) methods) of the interaction of the superoxide anion radical with a graphene-like plane containing various functional groups on its surface. It was established that such an interaction occurs due to the physical adsorption of the radical on the surface, and this process is significantly enhanced in the presence of ketone groups on the periphery of the cluster. The obtained data make it possible to develop highly effective antioxidants based on graphene and graphene oxide.
Failure mode characterizations of semiconductor lasers
Authors: Ren Zhanqiang , Li Qingmin , Qiu Bocang , Zhang Jin , Li Xirong , Xu Bin , Song Kechang , Li Bo
Published: September 2023

Catastrophic optical mirror damage (COMD) and catastrophic optical bulk damage (COBD) are the main factors that affect the reliability of semiconductor lasers. In this paper, we characterize the COMD and COBD failure modes by examining the voltage changes at the current point where failure occurs, as well as by using the electroluminescent technique. Our study reveals that the voltage has an increase at the failure current point for COMD samples, in which failure occurs due to the damage to the facet mirrors; for COBD samples, in which failure occurs inside the laser cavity, the voltage exhibits a decrease and the amount of voltage decrease is roughly proportional to the size of the damaged area.
Plastic-strain-induced magnetocaloric effect of Pt3Fe ordered alloy
Authors: Kobayashi Satoru , Hotta Yuri
Published: September 2023

We report a magnetocaloric effect of a plastically strained Pt3Fe antiferromagnet, in which ferromagnetism is induced due to the changes in the atomic arrangement around the {110} glide plane. The magnetic entropy change after the application of magnetic field increases with increasing applied plastic strain and shows a peak value of ∼0.1 J/K kg for an applied field of 50 kOe around the Néel temperature of 170 K. The magnetic entropy change can be due to the magnetization reversal of Fe magnetic moments in ferromagnetic domains formed around the {110} glide planes, and the peak temperature is influenced by the magnetic interaction between ferromagnetic domains and antiferromagnetic matrix. These observations suggest that a Pt3Fe chemically ordered alloy is a unique type of antiferromagnets in which the magnetocaloric effect can be induced and controlled by applied plastic strain.
Recent progress in performance improvement strategies for quantum dot sensitization methods: Challenges, achievements, and future prospects
Authors: Najm A. S. , Selvanathan Vidhya , Aljuwaya Thaar M. , Sabri Laith S. , Jamal M. S. , Abdullah Al-Zahrani Asla , Holi Araa Mebdir , Jaber Israa , Al Ghamdi Ahmed , Amin Majdi T. , Sopian K. , Ismail Raid A. , Moria Hazim , Bais Badariah , Majdi Hasan Sh , Chowdhury Shahariar , Sultan Abbas J. , Alhuzaymi Thaqal M.
Published: September 2023

In the recent past, there has been an increase in the use of semiconductor nanostructures that convert solar energy to electrical energy. This has encouraged the development of better and more efficient solar cells (SCs). Numerous investigations have been conducted into synthesizing novel semiconductor materials and tuning the electronic properties based on the shape, size, composition, and assembly of the quantum dots to improve hybrid assemblies. Recent studies that are determining the prospects of quantum dot SCs can form the basis for improving photovoltaic efficiency. Here, we have reviewed studies that investigated the sensitization methods for fabricating highly efficient SCs. We also discussed some examples that would help other researchers who want to sensitize quantum dot (QD) SCs. Thereafter, we analyzed the main and popular strategies that can be used for sensitizing the QD SCs within the limitations, advantages, and prospects of fabricating high-efficiency and stable QDs. During this work, we offered strong technical support and a theoretical basis for improving the industrial applications of QD. In addition, we provide a reference that can inspire other researchers who aim to improve the performance of SCs.
Embedding stochastic differential equations into neural networks via dual processes
Authors: Sugishita Naoki , Ohkubo Jun
Published: September 2023

We propose a new approach to constructing a neural network for predicting expectations of stochastic differential equations. The proposed method does not need data sets of inputs and outputs; instead, the information obtained from the time-evolution equations, i.e. the corresponding dual process, is directly compared with the weights in the neural network. As a demonstration, we construct neural networks for the Ornstein–Uhlenbeck process and the noisy van der Pol system. The remarkable feature of learned networks with the proposed method is the accuracy of inputs near the origin. Hence, it would be possible to avoid the overfitting problem because the learned network does not depend on training data sets.
Transitions between quasi-stationary states in traffic systems: Cologne orbital motorways as an example
Authors: Wang Shanshan , Schreckenberg Michael , Guhr Thomas
Published: September 2023

Traffic systems can operate in different modes. In a previous work, we identified these modes as different quasi-stationary states in the correlation structure. Here, we analyze the transitions between such quasi-stationary states, i.e. how the system changes its operational mode. In the longer run this might be helpful to forecast the time evolution of correlation patterns in traffic. Taking Cologne orbital motorways as an example, we construct a state transition network for each quarter of 2015 and find a seasonal dependence for those quasi-stationary states in the traffic system. Using the PageRank algorithm, we identify and explore the dominant states which occur frequently within a moving time window of 60 days in 2015. To the best of our knowledge, this is the first study of this type for traffic systems.
The influence of creep on precision stability in precision instruments with assembly errors
Authors: Su Liang , Chen Xiao , Xiong Jian , Jin Xin , Zhang Zhijing
Published: September 2023

In the adhesive assembly of precision inertial instruments, it is easy for the center of mass to shift due to creep in the adhesive structure, resulting in a reduction in the accuracy of the instrument. In the presence of ambient temperature variations, these center of mass shifts can change further, causing variations in the accuracy of the instrument, that is, the accuracy stability problem. This paper investigates this accuracy stability problem. Firstly, numerical simulation modeling of an adhesive structure with assembly errors is carried out, then the center of mass displacement of the structure due to creep of the adhesive structure under different temperature loads is analyzed, and finally, experimental verification of the simulation results is carried out by developing a structural creep experimental device to verify the validity of the simulation results. This thesis provides a theoretical reference for the stability control of the accuracy of adhesive structures with assembly errors.
Design of magnetic flux leakage detector for mine wire rope
Authors: Ren Ming-Yue
Published: September 2023

At present, the online detection technology of wire rope damage in coal mine hoisting needs to be improved. Given the large number of detection elements and high detection cost in the wire rope detection device, the magnetic flux leakage detection device of the wire rope damage detection system is designed. The magnetic sensor is selected. At the same time, in order to improve the strength of the magnetic leakage field at the defect and reduce the number of magnetic sensors, a magnetic focusing device is designed. The finite element simulation shows that the magnetic focusing device can effectively improve the sensitivity of defect detection. The above research provides the basis for the design of steel wire rope damage detection systems and is of great significance to ensure the safe and efficient operation of mine hoisting equipment.
Research and Application of Calibration Device for Fire Emergency Lighting Detector
Authors: Deng Bin , Guan Ze-Xin , Ma Xue-Feng , Ru-Jia  , Wang Da-Long , Sun Xiao-Yan , Zhang Yuan-Yuan , Dong Guang-Kun , Wang Wei-Zhao
Published: September 2023

In order to solve the problem of quantitative traceability of detection devices for fire emergency lighting and evacuation indication systems. Method analysis and research were conducted on parameters such as emergency switching time, emergency working time, DC charging voltage, DC discharge voltage, DC charging current, DC discharge current, environmental test temperature, and environmental test humidity. We searched for appropriate calibration methods for the technical characteristics of each parameter and designed a set of calibration devices for fire emergency lighting detectors. The test results show that the technical indicators of the calibration device can meet the traceability requirements of the fire emergency lighting and evacuation indication system.
The Influence of Ball Milling Time and Sintering Temperature on the Structural and Capabilities of FeCoCrNiMn High-Entropy Alloy
Authors: Ma Yutian , Wang Zhenming , Tang Xingchang , Cheng Ganghu , Liu Yajun , Chen Kexuan , Zhang Zhijian , Lu Sujun , Sun Yuanjun , Liu Junzhao
Published: September 2023

This study reports the fabrication of FeCoCrNiMn high-entropy alloy using high-purity powders of Fe, Co, Cr, Ni, and Mn through the processes of mechanical alloying (MA) and spark plasma sintering (SPS). We systematically investigated the effects of different ball milling times (10 h, 20 h, 30 h, 40 h, 50 h) and sintering temperatures (700°C, 800°C, 900°C, 1000°C, 1100°C) on the structure and capabilities of the alloy. The findings indicate that the atomic proportion of Fe:Co:Cr:Ni:Mn approach 1:1:1:1:1. The distribution of all elements is basically uniform, but the Cr element is slightly biased in the structure after 40 h ball milling. The voids in the structure are gradually decreasing as temperatures rise. The matrix structure is mainly composed of a white FCC matrix phase and a gray Cr-rich σ phase. The alloy structure is the densest. It has the highest density of 7.060 g/cm3, the highest compressive strength of 1480 MPa, and a plastic deformation of 13% when the SPS temperature reaches 1000°C. The FeCoCrNiMn high-entropy alloy is prepared by a ball milling time of 40 h, and spark plasma sintering of 1000°C has the best comprehensive properties.
Study on the influence of Hf, Zr and Mo elements on the mechanical properties of equimolar TiVNbTa refractory high-entropy alloy
Authors: Wu Gang , Xu Ziqi
Published: September 2023

The addition of alloying elements would improve the properties of refractory high-entropy alloys at room temperature and high temperatures. Hf, Zr and Mo elements were added in TiVNbTa refractory high-entropy alloys. Mechanical properties and microstructures after deformation were studied through compressive and tensile tests and microstructural characterization. Hf, Zr and Mo elements would increase the ambient strength of TiVNbTa alloy owing to increased atomic size difference and shearing modulus difference. However, Zr and Mo would deteriorate the ambient ductility, and Hf and Zr would decrease the high-temperature strength owing to lower shearing modulus and melting points. Moreover, the Zr-enriched BCC phase would precipitate after compression at 1000°C.
Study on preparation process and seawater corrosion resisting properties of chopped CF/PEEK composites
Authors: Zhu Hao , Li Yong
Published: September 2023

CF/PEEK composite material is widely used in marine engineering construction due to its characteristics of lightweight, high strength, corrosion resistance, and aging resistance, and it will inevitably produce side materials and wastes in the forming process. Therefore, the research on CF/PEEK recycling is of great significance. Due to the characteristics of PEEK’s high melting point and high viscosity of the solution, it is difficult to recycle and reuse such materials. In this paper, a certain amount of PEEK resin powder is added to improve the hot pressing technology of the chopped prepreg. Through a simulated seawater corrosion experiment, the influence of simulated seawater corrosion on the microstructure and mechanical properties of the composite materials is studied. Combined with the principal component analysis method, the corrosion resistance of the chopped CF /PEEK composite was evaluated comprehensively, which provided a reference for the recycling of thermoplastic prepreg and thermoplastic composite products. The results show that the surface quality and mechanical properties of the composites with resin powder are obviously improved. The resin matrix on the surface of the sample was subjected to salt corrosion by chloride ions in a simulated seawater solution to form local corrosion, resulting in pores, cracks, and other defects. The longer the corrosion time of simulated seawater is, the more serious the surface damage of the composite material is, and the more obviously the mechanical property declines. Principal component analysis showed that the resin content had little effect on the seawater corrosion resistance of chopped CF/PEEK composite.
Forming Performance of Multi-way Tubes in Hydroforming
Authors: Meng Zhenpeng , Liu Jianwei , Wang Binhao
Published: September 2023

The tube hydroforming technology is a rapid-forming technique in multi-way tube integrated and lightweight manufacturing. The forming performance of the multi-way tube under this technology was comprehensively analyzed and summarized in this paper. Firstly, the influencing factors, such as axial feed loading path and internal pressure, forming friction, and die transition fillet, in the process of multi-way tube forming were analyzed and summarized. Secondly, the optimization method of the multi-way tube forming performance in hydroforming was analyzed. Finally, the reduction of hydraulic expansion costs and the development of new hydroforming technologies were expounded.
The optimization of thermo-compression process parameters of continuous carbon fiber reinforced PEEK composites
Authors: Ma Xiaolong , Wen Lihua , Wang Shiyu
Published: September 2023

Thermoplastic composites with high performance have become the primary material developed for aerospace applications. However, there are still numerous challenges for high-quality thermo-compression molding of thermoplastic composites. This paper investigated the control mechanism of porosity in continuous carbon fiber (CCF) reinforced polyether-ether-ketone (PEEK) composites based on an orthogonal molding scheme, which examines the effect of thermo-compression process parameters on porosity. Further insights were obtained regarding the correlation among molding process parameters, porosity, and mechanical properties. The experimental results indicated that the significant factors affecting the bending performance of CCF/PEEK composites were molding pressure, temperature, and sequence holding time. Moreover, the viscosity of molten PEEK resin significantly affected the porosity of the composites, and the descending order of effect on the porosity of the composites was molding temperature, holding time, and molding pressure. Based on these results, we identified the optimal molding process conditions for CCF/PEEK composites, which were 405 °C, 1.5 MPa, and 30 min.
Study on interface bonding performance of honeycomb reinforced polyurethane composite molding structure
Authors: Wang Min , Ding Wuxue , Han Jingwei
Published: September 2023

Honeycomb reinforced polyurethane composite structure has excellent performance and has been used in more interior and exterior parts. Based on the integrated molding technology of honeycomb-reinforced polyurethane composite structure and skin fabric, three important factors affecting the interface bonding performance are proposed, the orthogonal test scheme is designed, and the process parameters of the product applied to the battery cover of the new energy vehicles are optimized and verified by taking the flat tensile strength as the index. The results show that the test can obtain the best process parameters, effectively improve the interface bonding performance of composite products, and can be used to guide the production and preparation of new energy vehicle battery cover products.
Synthesis and Performance Study of pH/Magnetic Dual Response Chitosan Based Emulsifiers
Authors: He Runna , Sun Shuangqing , Wang Zhikun , Hu Songqing
Published: September 2023

Recently, stimuli-responsive emulsions have been widely applied due to their excellent structural stability, biocompatibility, and environmental friendliness. For this application, the emulsion needs to be able to respond quickly to environmental stimuli with controlled stabilization and destabilization. This paper reports a novel composite Pickering emulsifier using Fe3O4 as the core, silica as the intermediate layer, and chitosan as the outer shell, which possesses a pH/magnetic dual responsive feature when deionized water is used as the water phase, and liquid paraffin is used as the oil phase to form an emulsion. Fe3O4@SiO2@chitosan has good paramagnetism and pH responsiveness to realize controlled magnetic and pH-responsive breaking of an emulsion when needed. The size of the composite emulsifiers ranged from 90 nm to 120 nm. The strong magnetic responsiveness enables rapid emulsion breaking at pH=3-11. When used as stabilizer particles, the chitosan shell behaves differently depending on pH. At pH≤2, fully protonated chitosan as the free chain segment and Fe3O4@SiO2 stabilized emulsions together. The overall stabilization of the emulsion (Fe3O4@SiO2@chitosan as emulsifier) can be obtained at pH>2, and emulsion breaking is achieved at pH≈pKa condition.
Study on the Effect of ELID Grinding on corrosion wear properties of Co-Cr Alloy
Authors: Li Jiwu , Zhang Hui
Published: September 2023

Contemporary Co-Cr alloys used in artificial joints can cause health complications in long-term applications. A pin-on-disc friction and wear testing instrument was used to evaluate the corrosion and abrasion of two types of Co-Cr alloys for artificial joints under simulated body fluid conditions after surface electrolytic composite grinding. Co-materials with lower carbon content displayed superior corrosion resistance than those materials with higher carbon content. Moreover, surface processing with electrolytic composite grinding produced a stable surface modification layer, which improved the surface hardness and formed an oxide film that inhibited metal ionization. The formation of precipitates in the corrosive environment is likely to improve the friction and wear properties of the material. As such, a variety of hardness was observed for the artificial joint friction disc and pin, especially when the hardness of the disc was higher than that of the pin, which can improve the friction and wear behavior of joints.
The Effect of Laser Cladding Lap Ratio of TC4 Alloy on Microstructure and Properties of Ni60 Coating
Authors: Wang Fei , Li Xiao , Peng Jiahui , Liu Zengzhi , Feng Xinyi
Published: September 2023

For improving wear resistance and hardness, Ni60 coatings were applied to TC4 alloy using laser cladding techniques. The effects of different lap ratios on the microstructure, microhardness, and wear resistance of the Ni60 coating were analyzed using an ultra-deep field microscope, XRD, microhardness tester and wear testing machine, and a suitable lap ratio was sought to obtain a coating with a better performance. The results showed that the Ni60 coatings with a 30% lap ratio had the best morphology and no obvious defects. From the bottom to the top, there are coarse columnar crystals, fine columnar crystals, equiaxed crystals, and acicular crystals, mainly composed of γ-Ni and some Cr7C3 and Cr23C6 phases. Therefore, the suitable lap ratio is 30%, and the microhardness of the coating at this parameter is 900 HV, which is about 2.5 times of the substrate (360 HV). The wear amount of the coating is 5.05 mg, which is about 11% of the substrate (44.23 mg). The average friction coefficient of the coating is about 0.41, which is 63% of the substrate (0.65). TC4 alloy’s wear resistance and microhardness can be significantly improved by applying suitable coating material and laser cladding parameters.
Study on effects of ultrasound on microstructure refinement at semi-solid statement of ultrasonic-assisted brazing SiCp/Al composites
Authors: Liang Jindi , Ma Lin , Zhu Chao , Zhou Changhzhuang , Zhu Zhi , Wang Chunxia
Published: September 2023

Ultrasonic composite brazing uses ultrasonic cavitation and acoustic flow effects to ameliorate the soakage property of SiC particles and brazing material, enabling flux-free brazing of SiCp/Al-MMCs under atmospheric conditions. However, its mechanical properties are limited by the performance of the brazing material, which is often difficult to apply in structures with high strength requirements. In order to break through the limitations of conventional ultrasonic composite brazing of SiCp/Al-MMCs, this paper uses 50 vol.% SiCp/Al MMCs as base material and Zn-16Al brazing material. It applies secondary ultrasound at different times during the solidification of the liquid brazing material to reduce the weld grain size and reinforce the weld intensity by using ultrasonic cavitation and acoustic flow effects. The results show that the addition of secondary ultrasound can reduce the α-Al size and make the SiC particles and α-Al evenly distributed in the joint, which can significantly reinforce the intensity of the weld. The shear performance enhanced with the increase of supersound application second, but too long secondary sonication caused atomization of the brazing material, resulting in unfilled brazing material in the weld, which seriously affected the properties of the weld.
Time-depending Reliability Analysis of O-ring Sealing Performance
Authors: Zhang Jie , Ma Yong , Xie Liyun
Published: September 2023

O-rings are commonly used due to their simple structure and excellent performance. However, the time-dependent creep behavior of rubber during usage can significantly impact the working performance and service life of the O-ring. The phenomenological creep constitutive model establishes a relationship between the deformation of rubber materials under creep conditions and time, by incorporating a creep function that considers the significance of damage. Based on the phenomenological creep constitutive model, we establish a simulation model for the contact pressure of an engine O-ring. This model characterizes the time-dependent degradation process of the O-ring’s sealing performance by tracking the variation of contact pressure and contact surface width over time. To account for the randomness of rubber material model parameters and compression amount, we develop a time-dependent reliability analysis model for the O-ring using the first-order second-moment (FOSM) method. The research findings can establish a theoretical foundation for the assessment, analysis, and evaluation of O-ring sealing’s time-dependent reliability.
The adsorption of U(VI) by persimmon tannin modified aminated polyacrylonitrile fiber
Authors: Wu Fan , Xie Shuibo
Published: September 2023

In this study, a green and efficient persimmon tannin functionalized polyacrylonitrile fiber (PAN-TETA-PT) was prepared and used to treat U(VI). The influence of pH value, adsorption temperature and time, and fiber material dosage on the adsorption U(VI) of PAN-TETA-PT fibers were investigated, and the kinetics, isotherm, and thermodynamics of fibers were analyzed. When the pH is 6, the temperature is 30°C, and the fiber dosage is 0.2 g·L−1, the adsorption rate of PAN-TETA-PT fibers to U(VI) was 96.5%, and the U(VI) adsorption capacity was 159.75 mg/g. The kinetic and isothermal studies show that the adsorption of PAN-TETA-PT fibers to U(VI) is chemisorbed and multilayer adsorption. The thermodynamic analysis reflects that the PAN-TETA-PT is spontaneously endothermic for the adsorbed U(VI).
Characterization on chain-assembly of polystyrene micro-particles via dielectrophoresis
Authors: Zheng Xiongbiao , Huan Zhijie , Ma Weicheng , Chen Zexiang , Zhang Zhemin
Published: September 2023

In this paper, the characteristic of pearl chain formation was investigated with the dielectrophoretic manipulation of polystyrene micro-particles. Comsol-based simulations and dielectrophoretic experiments were conducted to analyze the detailed influence factors. With different parameters such as voltage amplitude and particle size, the length of the pearl chain varies. Simulation results are consistent with experimental results, indicating that voltage amplitude is a critical factor for chain formation, while particle size has minimal impact. Additionally, particle chains exhibit slight orientation differences between the experiment and simulation. These results provide significant insight into the behavior of chain formation under the influence of dielectrophoresis and offer practical guidance for implementing dielectrophoresis technology in microfluidic chips and biosensors.
Checkered Clusters Forming Mechanism Design
Authors: Yang Dingyong , Wang Bo , Lu Zhengjie , Wu Peiheng , Liang Yongge
Published: September 2023

As an important and widely used tool in the process of mulberry silkworm breeding in China, the wooden checkered clusters have the advantages of a high cocooning rate, good reliability, and good water absorption. For the moment, wooden checkered cluster production is still dominated by manual assembly. Such production methods are inefficient. In light of this problem, this paper designs a kind of automatic wooden checkered clusters machine based on the standard for wood grid clusters with a length of 530 mm, a width of 355 mm, and a grid number of 12 * 24. The main structure of the machine includes four parts: a checkered clusters mold conveying mechanism, a checkered clusters sheet loading mechanism, a checkered clusters sheet pressing mechanism, and a square cluster mold. The finite element analysis of the crankshaft (circulating downward press checkered clusters sheet) of the main part ball screw (transferring power) is carried out, and the results meet the design requirements. The machine uses a programmable controller (PLC) to achieve precise control and real-time detection of the actions of all aspects of the machinery to ensure long-term operation of mechanical energy and to produce a wooden checkered clusters machine with excellent quality and stability, which improves the production efficiency of the checkered clusters by three times.
Theoretical study of sound absorption performance for Al2O3-polyurethane foam composite
Authors: Yuan Binxia , Hou Weiguang , Liu Jianben , Zhou Bing , Cao Lan
Published: September 2023

To reveal the sound absorption property and mechanisms of Al2O3-polyurethane (Al2O3-PU) composite materials in theory, the impedance tube model is established by using the finite element method in this paper. Meantime, the theoretical modal and the calculation method adopt the Johnson-Champoux-Allard (JCA) modal and the standing wave ratio method, respectively. By comparing the experimental and simulation values of PU and Al2O3-PU composites from 0 to 1250 Hz, the results prove that the JCA predicted values can match the actual measured values. To further predict the sound property of Al2O3-PU composites in the medium and high frequency, the diameter of 29 mm and length of 600 mm for the impedance tube is installed. Finally, the sound pressure distribution diagram of the impedance tube is obtained.
Simulation And Design of a Vertical Gallium Nitride JFET with Dual Lateral Heterojunction Channels
Authors: Huang Hao , He Wei , Yang Jiaying , Zheng Ziyang , Peng Fangxi
Published: September 2023

A novel vertical gallium nitride (GaN) junction field-effect transistor (JFET) is reported in this article. Through the setup of dual lateral heterojunction channels in the body, the current density is high while the p-type gallium nitride growth area can be adjusted to easily achieve enhanced mode. Based on the structure parameter settings in this article, through the device simulation software TCAD, and under the condition of selecting the appropriate p-type GaN growth region, the threshold voltage of the device is 1.1 V, the source output current density can reach 7.2 kA/cm2, the breakdown voltage is about 750 V, and the on-resistance is 0.52 mΩ·cm2. Finally, the test circuit is built, and the switching characteristics of the device proposed in this paper are simulated under the consideration of parasitic inductance.
Insights of the pH-dependent emission of carbon dots: a density functional theory study
Authors: Pan Yuye
Published: September 2023

The mechanism of luminescence in carbon dots has long been a topic of controversy, as accurately characterizing their structure has proven difficult. This has made it challenging to guide the design and synthesis of carbon dots, hindering the development of highly efficient fluorescent varieties. Understanding the mechanism and regulatory mechanisms of carbon dot luminescence at the molecular level is important not only from a theoretical perspective but also has practical value. Previous studies have suggested that the fluorescence emission wavelength of carbon dots can be altered by changing the pH of the carbon dot solution, but the mechanism behind this modulation is not yet fully understood. In this study, we used density functional theory calculations and excited state simulations with 2, 3-Diaminophenazine, a representative luminescent molecule found in molecular state luminescent carbon dots, to investigate the effect of protonation on the absorption and fluorescence emission spectra of carbon dots. We analyzed the electronic structure and spatial distribution of the luminescent molecules before and after protonation and found that the change in molecular dipole moment caused by protonation was responsible for the significant red shift in the fluorescence spectrum. To further verify our findings, we modified the substituted functional groups with different electron-pulling abilities in the corresponding luminescent molecules to modulate the molecular dipole. The results showed that the larger the dipole moment in the luminescent molecules with different substituted functional groups, the longer the fluorescence emission wavelength. Therefore, the protonation-induced change in molecular dipole is the main reason for the pH-dependent modulation of luminescence in molecular state luminescent carbon dots.
Experimental study on the removal of U(VI) from wastewater by chitosan modified with persimmon tannin
Authors: Zhang Haibo , Xie Shuibo
Published: September 2023

Persimmon tannin modified chitosan (PT-CS) microspheres were synthesized by a water bath method using sodium tripolyphosphate (STPP) as a cross-linking agent for the removal of U(VI) from wastewater. The results showed that the optimal preparation conditions for PT-CS were a ratio of PT to CS mass of 4:1 and a reaction temperature of 80°C. When the initial concentration of U(VI) was 5 mg/L, and the pH value was 1.5, the PT-CS was injected at 0.06 g/L, and the reaction was 2.5 h. The removal rate of U(VI) from water reached 99.2%. The results of the deep removal test of U(VI) from rare earth wastewater showed that the concentrations of U(VI) in the combined wastewater and extraction wastewater were reduced from 4.42 mg/L and 2.12 mg/L to within 0.02 mg/L at pH 2.0, respectively. In contrast, the removal rate of high concentrations of Ca2+ in the wastewater reached 99%, meeting the emission standards of the rare earth industry.
Design and Simulation Analysis of Parallel Manipulator
Authors: Zhang Xiaokang , Wang Weiru , Geng Kaizhen , Yang Jianjun
Published: September 2023

With the rapid development of domestic manufacturing, industrial robots have become widely used and become a research hotspot. In this paper, the classical three-degree-of-freedom parallel manipulator is taken as the analysis object, the plane three-degree-of-freedom parallel positioning platform is designed, its kinematics model is established, and the dynamic simulation analysis is carried out in ADAMS software, and the drive motor is selected according to the simulation results.
Design of a New Method for Oxidizing Polypropylene Wax through the Scraper Reactor and Its Characterization
Authors: Li Chenyang , Xiang Nan , Wang Chuanxing
Published: September 2023

In this paper, a new scraper reactor is developed to oxidize polypropylene wax, and the reactor is studied through the characterization of the product. Compared with the traditional polyolefin wax high-pressure reactor, the scraper reactor made all samples heated evenly through the outer wall heating, effectively avoiding the problem of inconsistent reaction progress caused by uneven heating. The scraper constantly updates the interface, making the product fully in contact with the air and ensuring the atmosphere conditions for introducing polar groups. The scraper reactor not only simplifies the reaction conditions greatly but also saves the cost of oxidation. The scraper reactor replaces the traditional high-pressure stirring reactor, the membrane scraper in the reactor replaces the traditional stirring, and the air is used as the oxidant. A one-step reaction could obtain high-quality oxidized polypropylene wax (OPPW). The reaction time and temperature effects on OPPW products in new oxidation equipment are discussed. Through oxidation reaction, polar groups such as -C=O and -COOH are introduced into PPW to perform better in the polar environment and improve its thermal stability.
Design of a Broadband Double-layer Absorber Using a Resistive Ink Based on Frequency-selective Surfaces Arrangement
Authors: Wang Jiawen , Fan Caizhi
Published: September 2023

The traditional way to enhance the absorption performance of absorbers is to optimize the structural parameters of the unit cell, taking no consideration of the coupling between units. Here, based on the first presented double-layer metamaterial absorber unit cell using resistive ink patterns printed on an FR-4 sheet, the impact of arranging the frequency selective surfaces within constrained units on the absorption performance is studied, providing a method to improve the absorption performance through absorption and phase cancellation of the unit cell by arranging frequency selective surfaces. The optimized double-layer absorber structure achieves over 90% absorption within 3.3~15.6 GHz with a small thickness of 10.05 mm, and exhibits a preferred absorption performance than the original one within the operating frequency band.
Design of integrated robot for risk waste transfer and disinfection
Authors: Lin Rongfeng , Fan Jianan , Sun Zhijin , Yan Yonghuan , Zhan Xianghui
Published: September 2023

In order to solve the traditional elimination process cumbersome, manual cannot involve part of the hidden places, single function, and other problems, we designed an integrated risk garbage transfer and elimination robot. The robot is integrated based on the parent and child machines. The mother robot completes the garbage transfer task and the child robot completes the indoor elimination task. With DJI STM32-F4 series as the core board, the integrated robot control system is composed of ultrasonic obstacle avoidance technology. This system can automatically identify and transport garbage, spray disinfectant and autonomous navigation for unmanned elimination. The combination of the integrated mother robot greatly improves the efficiency of elimination and provides support for the direction of disinfection and cleaning robots.