bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Co doping of (Ga, In) and 2N preferred orientation on the magnetic and optical properties of ZnO
Authors: Hou Qingyu , Qi Mude , Si Riguleng
Published: August 2023

Current research on the Zn1−xMxO1−yNy (M = Ga, In) system mainly focuses on the p-type property, where Ga–N or In–N has different preferred orientations for bonding. Studies on the magnetic, bandgap, and optical properties of ZnO co doped with N are also lacking. The generalized gradient approximation (GGA+U) plane wave ultrasoft pseudopotential method based on density functional theory is used to systematically investigate the effects of the magnetic, band gap, and optical properties of the system for addressing the aforementioned problems. Results show that the formation energy of the Zn1−xMxO1−yNy (M = Ga, In) system is negative, all doping is easy, and all doped systems are stable and magnetic. The magnetism comes from the double exchange effect of electron spin polarization. Research has found that the band gap in Ga–N or In–N bonding along the c-axis direction is narrower than that along the a-axis direction. In the low-energy region, the redshift of the absorption spectrum is more significant, and the absorption or reflection coefficient and the carrier polarization and activity are stronger. In particular, In–N forms bonds along the c-axis direction and is co doped with another N in ZnO, which results in the narrowest band gap and the most significant redshift in the absorption spectrum. The absorption of sunlight can also be achieved in the ultraviolet visible near-infrared region. The absorption or reflection coefficient and the carrier polarization and activity are relatively strongest. This work has certain reference value for the design and preparation of new solar cell light absorbing materials based on ZnO.
Effect of an inclined magnetic field on unsteady mixed convective stagnation point flow over a permeable stretching sheet with radiative heat transfer
Authors: Chen Haibo , Israr Ur Rehman M , Katbar Nek Muhammad , Hamid Aamir , Duraihem Faisal Z , Qi Haitao
Published: August 2023

In this study, we analyzed the time-dependent, 2D, inclined magnetohydrodynamics mixed convection stagnating point flow of nanoparticle toward a permeable stretchable surface with radiative heat effect. Four different types of water-based nanomaterials, namely titanium dioxide

T
i

O

2

,

copper

C
u

,

aluminum oxide

A

l

2

O

3

,

and copper oxide

C
u
O

are analyzed in this investigation. Numerous engineering disciplines, including energy systems, material processing, thermal management, and environmental engineering, can benefit greatly from research in mixed convection, MHD, and nanofluids. The boundary layer representations of the dominating partial differential equations PDEs are converted into strong nonlinear ordinary differential equations ODEs utilizing similarities approach. The ODEs are computed numerically employing 4th order Runge–Kutta methodology-based shooting scheme. Few special situations, a remarkable alignment is determined between the present study and the outcomes obtained in the existing research. The impact of numerous pertinent variables on the prominent quantities such as velocity, temperature and concentration distributions, drag friction coefficient and heat transport are demonstrated graphically. It is noticed that the velocity and thermal curve decrease as the nanoparticle volume friction factor increases. Moreover, it is analyzed that higher values of nanoparticle concentration diminishes the velocity and temperature distributions.
Entropy disorder and quantum correlations in two Unruh-deWitt detectors uniformly accelerating and interacting with a massless scalar field
Authors: Elghaayda Samira , Mansour Mostafa
Published: August 2023

This investigation focuses on studying the dynamics of entropy disorder and quantum correlations between two detectors interacting with a scalar field in a four-dimensional Minkowski space-time using the Unruh-deWitt model. The aim is to gain insights into the evolution of quantum resources in uniformly accelerated detectors that interact with a massless scalar field. To achieve this, useful metrics such as local quantum Fisher information (LQFI), quantum consonance, and linear entropy are employed to analyze the quantum correlations and entropy disorder. The results indicate that the quantum correlations are heavily reliant on the choice of the initial state of the detectors. Interestingly, the quantum correlations exhibit a surprising resurgence as the Unruh temperature increases for specific initial state parameters. However, for other values, the Unruh temperature takes over and leads to a monotonic decrease in the quantum correlations. In addition, the degree of disorder is observed to increase as the Unruh temperature increases. Furthermore, the investigation delves into how the energy spacing of the detector affects quantum correlations across various initial state parameters. Further elucidating the behavior of quantum resources in curved space-time, we demonstrate that some initial state parameters can cause sudden changes in correlation measures as a function of energy spacing. These results highlight the relevance of choosing adequate initial state parameters, as they have a significant impact on the variation of quantum resources in two Unruh-deWitt detectors.
The observed number counts in luminosity distance space
Authors: Fonseca José , Zazzera Stefano , Baker Tessa , Clarkson Chris
Published: August 2023

Next generation surveys will provide us with an unprecedented number of detections of supernovae Type Ia and gravitational wave merger events. Cross-correlations of such objects offer novel and powerful insights into the large-scale distribution of matter in the universe. Both of these sources carry information on their luminosity distance, but remain uninformative about their redshifts; hence their clustering analyses and cross-correlations need to be carried out in luminosity distance space, as opposed to redshift space. In this paper, we calculate the full expression for the number count fluctuation in terms of a perturbation to the observed luminosity distance. We find the expression to differ significantly from the one commonly used in redshift space. Furthermore, we present a comparison of the
number count angular power spectra between luminosity distance and redshift spaces. We see a wide divergence between the two at large scales, and we note that lensing is the main contribution to such differences. On such scales and at higher redshifts the difference between the angular power spectra in luminosity distance and redshift spaces can be roughly 50%.
We also investigate cross-correlating different redshift bins using different tracers, i.e. one in luminosity distance space and one in redshift, simulating the cross-correlation angular power spectrum between background gravitational waves/supernovae and foreground galaxies. Finally, we show that in a cosmic variance limited survey, the relativistic corrections to the density-only term ought to be included.
Prospects for detecting anisotropies and polarization of the stochastic gravitational wave background with ground-based detectors
Authors: Mentasti G. , Contaldi C.R. , Peloso M.
Published: August 2023

We build an analytical framework to study the observability of anisotropies and a net chiral polarization of the Stochastic Gravitational Wave Background (SGWB) with a generic network of ground-based detectors. We apply this formalism to perform a Fisher forecast of the performance of a network consisting of the current interferometers (LIGO, Virgo and KAGRA) and planned third-generation ones, such as the Einstein Telescope and Cosmic Explorer. Our results yield limits on the observability of anisotropic modes, spanning across noise- and signal-dominated regimes. We find that if the isotropic component of the SGWB has an amplitude close to the current limit, third-generation interferometers with an observation time of 10 years can measure multipoles (in a spherical harmonic expansion) up toℓ= 8 with 𝒪(10-3– 10-2) accuracy relative to the isotropic component, and an 𝒪(10-3) amount of net polarization. For weaker signals, the accuracy worsens as roughly the inverse of the SGWB amplitude.
Multi-scalar theories of gravity with direct matter couplings and their parametrized post-Newtonian parameters
Authors: Lacombe Osmin , Mukohyama Shinji
Published: August 2023

We study theories of gravity including, in addition to the metric, several scalar fields in the gravitational sector. The particularity of this work is that we allow for direct couplings between these gravitating scalars and the matter sector, which can generally be different for the source and the probe of gravity, in addition to the universal interactions generated by the Jordan frame metric. The weak gravity regime of this theory, which would describe solar-system experiments, is studied using the parametrized post-Newtonian (PPN) formalism. We derive the expression of the ten parameters of this formalism. Among them, ζ
3 and ζ
4 are modified with respect to their values in the theories without direct couplings. This fact holds even after eliminating the direct couplings between the gravitating scalars and the energy density of the source, by redefinition of the Jordan frame. All other PPN parameters are insensitive to the direct couplings once in the correctly identified Jordan frame. When direct couplings are different for the source and the probe of gravity, they make non-relativistic probes deviate from the geodesics of the PPN metric in this frame, already at Newtonian order. Such
couplings would thus be directly
detectable and would have been excluded by experiments.
This shows that, contrary to the claims in the recent literature, it is impossible to screen the presence of gravitating scalars relying only on a curved target space and direct couplings to matter.
Quantum Zeno effect in a classical viscous medium
Authors: Sazonov S V
Published: August 2023

Based on the formalism of quasi-classical canonical quantization, the translational motion of a particle in a viscous medium is studied. The case is considered when, in addition to the resistance forces, an external conservative force acts on the particle. It is shown that due to the forces of viscous resistance of the medium, the initial coherent state of the particle does not decay. This behavior of the wave function is accompanied by a partial suppression of the quantum properties of the particle. In this case, a viscous medium should be considered as a classical device that continuously measures the state of a particle. Therefore, the stability of the coherent state of a particle can be interpreted as a manifestation of the quantum Zeno effect.
Functional brain connectivity indexes derived from low-density EEG of pre-implanted patients as VNS outcome predictors
Authors: Germany Enrique , Teixeira Igor , Danthine Venethia , Santalucia Roberto , Cakiroglu Inci , Torres Andres , Verleysen Michele , Delbeke Jean , Nonclercq Antoine , Tahry Riëm El
Published: August 2023

Objective. In 1/3 of patients, anti-seizure medications may be insufficient, and resective surgery may be offered whenever the seizure onset is localized and situated in a non-eloquent brain region. When surgery is not feasible or fails, vagus nerve stimulation (VNS) therapy can be used as an add-on treatment to reduce seizure frequency and/or severity. However, screening tools or methods for predicting patient response to VNS and avoiding unnecessary implantation are unavailable, and confident biomarkers of clinical efficacy are unclear. Approach. To predict the response of patients to VNS, functional brain connectivity measures in combination with graph measures have been primarily used with respect to imaging techniques such as functional magnetic resonance imaging, but connectivity graph-based analysis based on electrophysiological signals such as electroencephalogram, have been barely explored. Although the study of the influence of VNS on functional connectivity is not new, this work is distinguished by using preimplantation low-density EEG data to analyze discriminative measures between responders and non-responder patients using functional connectivity and graph theory metrics. Main results. By calculating five functional brain connectivity indexes per frequency band upon partial directed coherence and direct transform function connectivity matrices in a population of 37 refractory epilepsy patients, we found significant differences (p < 0.05) between the global efficiency, average clustering coefficient, and modularity of responders and non-responders using the Mann–Whitney U test with Benjamini–Hochberg correction procedure and use of a false discovery rate of 5%. Significance. Our results indicate that these measures may potentially be used as biomarkers to predict responsiveness to VNS therapy.
Robust neural tracking of linguistic speech representations using a convolutional neural network
Authors: Puffay Corentin , Vanthornhout Jonas , Gillis Marlies , Accou Bernd , Van hamme Hugo , Francart Tom
Published: August 2023

Objective. When listening to continuous speech, populations of neurons in the brain track different features of the signal. Neural tracking can be measured by relating the electroencephalography (EEG) and the speech signal. Recent studies have shown a significant contribution of linguistic features over acoustic neural tracking using linear models. However, linear models cannot model the nonlinear dynamics of the brain. To overcome this, we use a convolutional neural network (CNN) that relates EEG to linguistic features using phoneme or word onsets as a control and has the capacity to model non-linear relations. Approach. We integrate phoneme- and word-based linguistic features (phoneme surprisal, cohort entropy (CE), word surprisal (WS) and word frequency (WF)) in our nonlinear CNN model and investigate if they carry additional information on top of lexical features (phoneme and word onsets). We then compare the performance of our nonlinear CNN with that of a linear encoder and a linearized CNN. Main results. For the non-linear CNN, we found a significant contribution of CE over phoneme onsets and of WS and WF over word onsets. Moreover, the non-linear CNN outperformed the linear baselines. Significance. Measuring coding of linguistic features in the brain is important for auditory neuroscience research and applications that involve objectively measuring speech understanding. With linear models, this is measurable, but the effects are very small. The proposed non-linear CNN model yields larger differences between linguistic and lexical models and, therefore, could show effects that would otherwise be unmeasurable and may, in the future, lead to improved within-subject measures and shorter recordings.
Study on the catalytic performance of a new double-shell composite energetic material
Authors: Fu Yu , Ba Shuhong , Feng Lu , Xia Ping , Sun Wendong , Zhang Bo , Zhao Yuanyu , Tian Jianing , Wang Fei
Published: August 2023

To improve the pyrolysis of ammonium perchlorate (AP), the effects of P-N junction metal oxides with different coating sequences on thermal decomposition were compared. AP / ZnO / ZnCo2O4 double-shell composite energetic materials and AP / ZnCo2O4 / ZnO double-shell composite energetic materials were manufactured by the liquid phase deposition method. XRD, FT-IR, and TEM characterize the structure of samples. The self-catalytic properties of double-shell composite energetic materials were investigated by differential thermal analysis (DTA). XRD, FT-IR, and TEM results show the formation of a P-N junction. The double-shell composite energetic material was successfully prepared and had a good coating effect. DTA results show the Pyrolytic peak of AP / ZnO / ZnCo2O4 double-shell composite energetic materials has been drowned to 262.85 °C. The decomposition peak of AP / ZnCo2O4 / ZnO double-shell composite energetic material is 272.31 °C, and the difference between the two is obvious. The coating of N-type metal semiconductor material can greatly improve the autocatalytic performance of the material, giving a new idea for designing AP catalysts.
Preparation of MIL-101(Fe, Al)/MoS2 and its Adsorption of Tetracycline Hydrochloride
Authors: Li Yue , Liu Zhuannian , Zhou Rui
Published: August 2023

A new adsorbent material MIL-101(Fe, Al)/MoS2 was composed by a solvothermal pathway for the adsorption of tetracycline hydrochloride simulated wastewater. The material was analyzed through XRD. Influences of adsorption time, initialization concentration, and pH on adsorptive effect were explored. It turned out that MIL-101(Fe, Al)/MoS2 on tetracycline hydrochloride adsorption reached equilibrium at approximately 180 min and the adsorptive amount of MIL-101(Fe, Al)/MoS2 for tetracycline hydrochloride was 118.96 mg/g at adsorption equilibrium. In contrast to MIL-101(Fe, Al), the adsorptive effect of MIL-101(Fe, Al)/MoS2 composite material on TC was substantially improved. The adsorptive process was more in accord with the Lagergren second-order kinetic model and Langmuir adsorption isotherm model. Besides, the TC adsorption on MIL-101(Fe, Al)/MoS2 was better under neutral conditions.
CoNiMn-Layered Double Hydroxide/Ti3C2TxNanosheet Composites for Enhanced Pseudocapacitive Performance
Authors: Fang Junyu , Wen Da , Zhang Zheng , Zheng Dan , Meng Aiyun , Su Yaorong , Zhou Shuang
Published: August 2023

Layered double hydroxides (LDHs) are considered prospective pseudocapacitors materials owing to their large theoretical capacitance and excellent redox capability. However, the low electrical conductivity and severe aggregation still hinder their practical applications. Herein, we synthesize CoNiMn-LDH/Ti3C2Txnanosheet composites, of which Ti3C2Txnanosheets enhance the electrical conductivity and provide a large surface area for LDH anchoring. Using metal-organic frameworks (MOFs) as sacrificial templates, the CoNiMn-LDHs are synthesized on the surface of Ti3C2Txnanosheets via ion exchange, and the original organometallic hollow frameworks of the MOFs can be well retained. The as-prepared CoNiMn-LDH/Ti3C2Txnanosheet composite delivers the largest specific capacitance as high as 1035 F g−1at 1 A g−1and retains 73.6 % of the capacitance at 10 A g−1. Moreover, the material of the electrode exhibits superior capacitance retention of 95.6 % with 5,000 charging/discharging cycles. This study might provide useful guidance for designing and constructing high-performance pseudocapacitive materials.
Constructions and applications of MXene-based porous films
Authors: Jiang Yuchen , Lu Zan , Xin Binjie , Zhang Zhihao , Gao Di
Published: August 2023

MXene-based films (MBFs) have a graphic structure composed of a horizontal arrangement of MXene thin tablets and/or layer interval parts. It usually has high electrode density, but high-rate charge transfer is limited, and ions are transmitted to oxidize the activity site. To overcome these problems, it is necessary to convert the plane configuration of the MXene membrane into an interactive structure with an open and porous architecture. In this paper, the first discovered and most widely studied Ti3C2Tx MXene materials are used as an example to introduce the unique construction methods of MXene-based porous film structures, structure-effect relationships, and the applications: supercapacitor, terahertz electromagnetic shielding, and flexible sensing, which show significantly improved performance.
Study on SH wave propagation in the elastic metamaterial layer
Authors: Wu Zhiguang , Shu Haisheng
Published: August 2023

Elastic metamaterial (EM) is a new type of structured material mainly built with repeatedly arranged sub-wavelength unit cells. EMs have shown many surprisingly new dynamic properties and provided us with a new idea for elastic wave/vibration control. Although a large amount of work has been conducted by researchers, wave behaviors in some important waveguides constructed with EM remain for further investigation. In this work, SH (shearing horizontal) wave propagating in the EM layer is studied. The effects of the abnormal properties of effective medium parameters (EMPs) on the SH wave dispersion features are discussed by comparison with a classical elastic layer. Our study shows that the behavior of EMPs can significantly influence the dispersion properties of SH wave propagation within the EM layer. Moreover, no SH surface wave mode could be supported near the stress-free surface of the EM layer, and the SH wave traveling in the EM layer must be composed of bulk wave components, and hence it will be blocked completely in those EM layers with imaginary effective transverse wave velocity which can be realized by single negative effective density or shear modulus. This work may serve as a theoretical reference for relevant metamaterial-based elastic wave/vibration control.
Study on the effect of tempering on the impact abrasive wear performance of 45Si2MnCr2Mo ultra-high strength steel
Authors: Yang Ming , Chen Xiaohua , Wang Zidong , Pan Peng
Published: August 2023

In this paper, three-body impact abrasive wear tests of 45Si2MnCr2Mo ultra-high strength steel (UHSS) at different tempering temperatures were carried out by using the MLD-10 impact abrasive wear machine. The effects of different tempering temperatures on the wear weight loss and the depth of the hardened layer of UHSS were investigated. The results show that the weight reduction rate of the steels tempered at 150 and 220 °C decreases at first and then increases with time, but the steels tempered at 290 and 360 °C gradually increase with time. The surface and subsurface areas of UHSS are strengthened by work hardening after wear. The wear performance of UHSS should consider the change of weight reduction rate with time rather than just considering short-term weight loss. UHSS tempered at 150 °C has the best comprehensive surface hardness, hardening percentage, and effective hardened layer depth, and the wear process is more uniform.
Mechanical Property of New Cast High Manganese Steel and Its Application
Authors: Zhou Liyan , Sun Wei
Published: August 2023

Based on the traditional Mn13, the new cast high manganese steel was prepared by adding different Cr, Mo, B, and Re elements in the composition. Its microstructure, mechanical properties, and wear quantity of surface were investigated. Results show that after water toughening, the pearlite dissolved and a few linear carbides were kept at the boundary of grains in the microstructure. All of the hardness was more than 220 HB, impact toughness reached or exceeded 140 J/cm2, and ultimate tensile strength was 753 MPa. The lowest abrasive wear quantity was 0.02 g. The newly cast high manganese steel was applied to produce breaking teeth casting of the crusher. Velocity and temperature fields were simulated to predict some defects during the mold filling and solidification process with finite element software for 4 foundry processes. The optimal technological parameter was adapted to make breaking teeth components.
Resistance spot welding properties of galvanized DP590 duplex steel and aluminum alloy A6061-T6
Authors: Wang Chunliang , Feng Qiaobo , Wang Jie , Yu Nie , Lei Haiyang , Zhou Guoyan
Published: August 2023

A6061-T6 aluminum alloy and DP590 duplex steel with a galvanized layer for resistance spot welding, the investigation of welding current on the A6061-T6 aluminum alloy / DP590 steel joint interface intermetallic compound and the effect of shear resistance. The results found that when the welding current increased, the intermetallic compound layer first became thicker and thinner, while the joint shear force always increased, and when the welding current reached 13 kA, the shear force was 4.0 kN.
Preparation of porous iridium-ruthenium-based acidic water oxidation catalyst by ascorbic acid reduction and evaporation
Authors: Chen Hui , Deng Runxu , Gao Shixin , Liu Feng
Published: August 2023

Green hydrogen is the ultimate direction for energy development technology. Hereon, the porous materials of promoted iridium-ruthenium-based catalyst were prepared by ascorbic acid reduction and evaporation drying methods. The unsupported iridium ruthenium-based catalysts were porous structures, characterized by scanning electron microscopes (SEM). In 0.5 mol·L−1 H2SO4, the electrochemical oxygen precipitation reaction overpotential was only 251 mV at 10 mA·cm2, compared to commercial 303 mV. The polarization overpotential was not significantly reduced, after 20 000 cycles of accelerated cyclic aging experiments. The porous structure of the iridium-ruthenium-based catalysts showed higher catalytic activity for oxygen precipitation than the commercial IrO2(ZrO2) catalysts. Porous materials could improve the activity of catalysts, which provides a good research idea for the synthesis of electrocatalysts.
Study on the effect of enhanced magnesium and copper contents on microstructure and property of Al-Zn-Mg-Cu alloys with high zinc element content during fabrication processes
Authors: Zhou Hua , Wen Kai , Yin He , Yu Ming-yang , Shi Guo-hui
Published: August 2023

Magnesium and copper elements can significantly influence precipitation characteristics, and furtherly change the property of final products in Al-Zn-Mg-Cu alloys. The current work chose a high Zn-containing Al-Zn-Mg-Cu alloy with synchronously enhanced magnesium and copper contents. Related microstructure and property were thoroughly investigated during the preparation process. The results showed that the solidification phase in as-cast microstructures was mainly AlZnMgCu. At the same time, the amount of it was enhanced with the increased content of magnesium and copper elements. After homogenization by 400°C/10h+472°C/56h, the eutectic ones dissolved into the α(Al), and only a sporadically distributed Fe-rich phase was observed. Mg(Zn, Cu, Al)2 phases with dense distribution and small size existed in extruded microstructure, most of them were re-dissolved in the α(Al) by solution treated with a regime of 472°C/4h. After single aged by 120°C/24h, the strength possessed an incremental trend with the increased content of magnesium and copper elements, while the elongation and electrical conductivity showed an opposite trend. MMC alloy possessed the largest fracture toughness value. When the alloys were aged by double-stage regimes, the strength, and electrical conductivity had incremental trends, while elongation possessed a decremental trend, as same as the single-aging ones.
The effects of Co percent on structure and electrochemical properties of LiNixMnyCo1-x-yO2 cathodes
Authors: Bai Xue , He Rui , Wei Aijia , Ji Yangfan , Zhang Lihui , Liu Zhenfa
Published: August 2023

The stretched supply and high cost of cobalt harm commercial Lithium-ion batteries production and manufacturing, and the fundamental understanding of the influences of Co percent on the structure and electrochemical performance of LiNixMnyCo1-x-yO2 cathodes is lacking. Therefore, hydrothermal and high-temperature solid-phase methods prepared the LiNixMnyCo1-x-yO2 cathodes with different Co content. The basic properties of materials, such as crystal structure and overall morphology, are studied in detail using common XRD diffraction and scanning electron microscopy techniques. Meanwhile, the electrochemical performance was tested by a battery-testing workstation. For different Co content, all LiNixMnyCo1-x-yO2 cathodes present an intact layered structure with R-3m space group and exhibit acceptable reversible discharge specific capacities. The cathodes deliver higher initial discharge-specific capacity when the Co content is 0.08. The LiNi0.92Co0.08Mn0.1O2 presents higher discharge capacities of 191.8, 182.6, 167.3, 157.9, 143.8, and 116.6 mAh g−1 at different rates from 0.2 to 10 C, respectively. The electrochemical performance analysis results indicate that the LiNi0.92Co0.08Mn0.1O2 cathode exhibits better rate capacities and cycle performance before the 200 cycles.
Preparation and Properties of New Starch-based Ceramic Body Reinforcing Agent
Authors: Nie Yufan , Li Yinger , Fan Bo , Qi Tao , Lu Ke , Liu Hongbo , Wang Ying
Published: August 2023

In ceramic production, the finished product is often fragile and defective due to low green strength, which greatly affects the ceramic yield and the preparation of advanced ceramics. It is important to develop a ceramic body reinforcement agent with an obvious reinforcement effect, no impact on slurry properties, low cost, and simple preparation process. In order to solve the above problems and analyze the influence of modification conditions on the green body enhancement results, the properties of three common starches were compared and corn starch was modified by substitution method to prepare a novel starch-based ceramic green body enhancer. The structural characterization and enhancement effect of the modified corn starch prepared by infrared spectroscopy and X-ray diffraction analysis showed that the addition of starch-based ceramic green body enhancer made the green body enhancement rate reach 61% and the mildew resistance increase for more than 4 days. The best preparation conditions for modified starch were soluble corn starch 33.3 g, 85% ethanol solution 300 mL, sodium hydroxide 16.46 g, chloroacetic acid 26.6 g, and reaction at 40 °C for 2.5 h.
Contour-Line Optimization and Performance Analysis of Yin-Yang Rotor in Twin-Screw Compressor
Authors: Chen Changsheng , Zhou Yalan , Wang Yuewu , Chen Biwen , Bian Jiahui , Wo Yang
Published: August 2023

To investigate the influence of the profile design of the Yin and Yang rotor on the performance of the twin-screw compressor such as outlet flow, exhaust pressure and turbulence intensity. In this paper, the Yin and Yang rotor profile optimization is carried out based on a type of twin-screw compressor, and the optimization profile and the original profile are numerically simulated, and the performance curves of the two groups of profile parameters are obtained. The results show that the optimized profile has better performance parameters under the same flow condition, that is, it is more stable in operation and has better vibration and noise index in operation.
A study on the variation of mechanical properties of Ti-8Al-1Mo-1V titanium alloy after electro-shocking treatment
Authors: Yao Yupeng , Zhou Jian , Zhao Hongjie
Published: August 2023

The electro-shocking treatment (EST) was a rising method for the strengthening of titanium alloys. This work conducted EST on Ti-8Al-1Mo-1V titanium alloy specimens with the purpose to shed insights on the influence of EST on the properties of the alloy. The results indicated that the number of the pulse current increased, the properties of the Ti-8Al-1Mo-1V titanium alloy were notably improved, and the fracture mode varied from ductile fracture to a mixed fracture mode of brittle and ductile.
Study on the effect of aging treatment on the mechanical properties of the die-forged Al-Cu-Mg-Ag heat-resistant alloy
Authors: Chen Lifang , Zhu Kai , Liu Qilong , Lin Haitao , Wang Zhengan , Liu Hongwei
Published: August 2023

In this research, the microstructure of large industrial Al-Cu-Mg-Ag alloy die-forgings at key load-bearing locations was examined using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and electron back-scattered diffraction (EBSD). Also, the impact of various age treatment methods on the mechanical characteristics of die-forged Al-Cu-Mg-Ag alloys was investigated. The findings indicate that deformed grains predominate in this alloy’s grain type at this site. The microstructure of the alloy exhibits distinct forging flow lines, according to the results of color metallographic characterization. In the direction of matrix deformation, the alloy’s second-phase particle distribution is streamlined. The peak aging time of the alloy gradually shortens as the temperature of the aging treatment rises. The mechanical characteristics of the alloy first show a rising trend at various aging treatment temperatures, followed by a steady fall as the aging duration is extended. For this forged aluminum alloy, optimization suggests that the ideal single-stage aging heat treatment regime is 165°C/20h.
Powder Preparation by Vacuum Atomization and 3D Printing Forming Performance of 316 Stainless Steel
Authors: Zhang Fenglong , Wang Shiyi , Yang Yu , Zhang Kexin , Li Zhenlong , Wei Zhaozhao , Li Likun
Published: August 2023

This work describes the process of preparing 316 L stainless steel powder by vacuum atomization, then a 3D print sample of 316 L stainless steel is prepared by selective laser melting (SLM) experiments. Over 77% of the powder particle size distribution ranges from 15 to 45 μm. The prepared sample shows a smooth surface with few satellite globules and high sphericity with the 4.5 Mpa atomization pressure. Under these atomization pressure conditions, the tensile strength can reach 798 Mpa and the elongation up to 32.3%. This work demonstrated that 3D printing metal materials with high tensile strength and good plasticity could be obtained under appropriate atomization pressure conditions.
Design of self-healing carbon-based hydrogels for wearable motion monitoring
Authors: Li Wen , Zhu Congcong , Wang Ping , Tao Luqi
Published: August 2023

Conductive hydrogels have been extensively exploited in wearable medical monitoring, intelligent robotics, and human-machine interaction. Here, we construct an interpenetrating network of self-healing hydrogel using gelatine-modified carbon nanotubes (G/C) and polyvinyl alcohol (PVA) polymerization chains (given as PGC). A bonding agent, borax, was chemically cross-linked with PVA molecular chains to impart self-healing ability. The addition of G/C enhances the tensile behavior and conductivity of the hydrogels. With superior sensing capability and favorable biocompatibility, the PGC hydrogel described in this study offers valuable insights for developing ideal wearable strain sensors.
Research on the gel casting process and flexural strength of high-stability alumina ceramics
Authors: Deng Zhe , Liu Rong
Published: August 2023

Gel casting is an advanced wet-forming method for ceramics. In this paper, Isoabm 104 is selected as the dispersant and gelation agent for gel casting. The optimization of gel casting slurry and the preparation of the green and sintered alumina bodies are investigated. TAC reduces the viscosity of the slurry significantly due to electrostatic interaction. Isopropanol alcohol and vacuum tank eliminates the slurry’s air bubbles, thus improving the density of green bodies. A staged drying process is necessary to produce smooth and defect-free green bodies. After optimization of the slurry formulation and gel casting process, alumina ceramics with a Weibull modulus of 11.1 are successfully prepared.
Synthesis and properties of novel drug-loaded nano micelles based on Jerusalem Artichoke polysaccharides.
Authors: Gao Ying , Qi Weiguo , Song Zifan , Zhang Ningning , Yang Yang , Song Yimin
Published: August 2023

To develop a novel polymeric nano micelle drug delivery system, JAP-based drug-loaded nano micelles (FFC/JAP-HA) were prepared by chemical modification/ultrasound/molecular self-assembly method. The results showed that JAP was connected with hyaluronic acid (HA) by an ester bond, the particle sizes of FFC/JAP-HA were 329.8 ± 2.3 nm, and the critical micelle concentration (CMC) of FFC/JAP-HA was 3.3 × 10−2 mg/mL. The hemolysis results, cytotoxicity test results, and histological results also showed that the FFC/JAP-HA had good biocompatibility. Furthermore, pharmacokinetic results suggested that the retention time (MRTINF_obs) of FFC/JAP-HA could be extended to 918.23 ± 37.25 min, which laid a foundation for the development of a new polymeric nano micelle drug loading system.
Programmable Multi-stable Structure Based on Cosine Beam
Authors: Wang Xin , Chen Zhuo , Yang Ao Hao , Zhou Deng Yu
Published: August 2023

Mechanical metamaterials with multi-stable properties are an emerging field of interest. In this paper, we present a novel 3D bi-stable cell element with negative stiffness characteristics designed based on a cosine-curved beam. Static compression simulations were performed for the single-cell model and the series model. Using “E” and “F” states as programming units, five array models were designed to analyze the stiffness variation rules. Dynamic simulations were conducted to compare the energy absorption rate and collision force of the model with variable stiffness. The conclusion shows that the structure has multi-stable and negative stiffness characteristics, and its stiffness can be adjusted in the range of 113.0 to 197.6 N/mm. Additionally, the energy absorption rate can be adjusted in the range of 8% to 65%. This study has made the structure configurable after manufacturing, breaking through the application limitations of predefined objects, and broadening its application prospects.
Thermal stability of epoxy-based Sn-58Bi solder joint
Authors: Li Xiao-guang , Yang Xiao-jun , Ma Limin , He Ding-yong
Published: August 2023

The epoxy(EP)-based Sn-58Bi solder paste consists of a curable flux and Sn-58Bi particles. In addition to its function as a flux, the curable flux forms a cured shell on the periphery of the solder joint. Under appropriate process parameters, the EP-based Sn-58Bi solder paste can form solder joints with a shell-core structure on the Cu substrate. Compared to conventional Sn-58Bi solder paste, the solder joint of EP-based Sn-58Bi solder paste has a higher heat resistance and joint strength. To investigate the heat resistance of the solder joint of EP-based Sn-58Bi solder paste, the thermal cycle test was carried out in the temperature range of 130-170°C. Metallographic microscopy and scanning electron microscopy (SEM) were used to observe the interfacial microstructure of the solder joints and to analyze the difference in the microstructure of the solder joints in relation to the thermal history. The results show that the solder joint interface of the EP-based Sn-58Bi solder paste is more stable than that of the conventional Sn-58Bi solder paste, indicating that the cured EP shell on the periphery of the solder joint can effectively improve the thermal stability of the solder joint.
Design of a constitutive model based on the evolution of creep cavities damage for 9Cr-1Mo steel
Authors: Cheng Huaxing , Yan Yabin
Published: August 2023

Considering the impact creep cavity evolution damage of 9Cr-1Mo steel, a new creep constitutive model was established based on the damage-coupled Norton equation and the strain hardening term in the theta projection method model, and the parameters were solved by optimization technique. The creep behavior was compared with that of the Kachanov-Robotnov model. According to the simulation results, the proposed constitutive model can represent the strengthening phenomenon during the first creep stage of 9Cr-1Mo steel. It provides a more accurate description of the behavior during the three creep periods.
Application of the Substructure Method in Direct Calculation of Hull Structures
Authors: Wang Xiaoqiang , Li Jiahao , Zhang Zhenhai
Published: August 2023

To study the application of the substructure method in the direct calculation of ship hull structures, this paper uses MSC. PATRAN software for modeling. Based on the full ship model, the structure components corresponding to the units before the tail structure are deleted to form a finite element submodel that only contains the tail structure. The constraints and various design loads under each working condition are retained on the units of the tail section model. The node displacement at the “boundary” of the submodel obtained from the full ship model is used as its constraint condition to study the correctness and applicability of the finite element analysis of the tail section structure based on full ship FEA (Finite Element Analysis). Comparing the deformation and stress results of the stern of the main hull obtained from the full ship model and the tail section model, it is shown that the substructure method is correct and feasible.
Construction of the visco-elastic constitutive model for polyethylene terephthalate in a rubbery state
Authors: Yin Zhansong , Zeng Lianghua , Peng Engao
Published: August 2023

Polyethylene terephthalate (PET) is an important commercial engineering polyester thermoplastic used in beverage bottles. PET is usually biaxial stretched above its glass transition temperature (T
g
) and molded into containers by injection stretch blow molding (ISBM) under a rubbery state. This paper constructs a visco-elastic constitutive model for PET above T
g
. The stress-strain behaviors of PET can be explained by the Eyring activation mechanism and the Arruda-Boyce eight-chain rubber model(A-B model). In the constitutive model, the overall stress of PET is equivalent to the sum of Eyring dashpot and A-B model stresses. The uniaxial tensile test data confirms the constitutive model under three stretch rates and temperatures. The constitutive model can furtherly be applied in the numerical simulation of the PET ISBM process.
Design of a Fatigue Analysis Method for Adhesive Bonding in Wind Turbine Blades Considering Multiple Uncertainties
Authors: Liu Haodong , He Zhenfeng , Li Yongjie , Liu Zheng
Published: August 2023

Adhesive bonding is widely distributed in wind turbine blades, and the fatigue performance analysis of the bonded layer is critical to investigate the safety and reliability of the whole structure. Various uncertainties influence the fatigue performance of adhesive bonding, originating from material, load, etc. A method for simulating fatigue that considers multiple uncertainties has been proposed in this paper based on the Cohesive Zone Model (CZM) and stochastic finite element theory. The study can provide reliable results for fatigue performance investigation of adhesive bonding in wind turbine blades.
Study on the effect of annealing and solution treatment on the peripheral coarse grain of 2195 alloy
Authors: Wang Tao , Wen Kai , Lin Ben , Li Yanan , Xiong Baiqing
Published: August 2023

In the actual production process, some aluminum alloys need to go through annealing heat treatment followed by solution treatment; this paper explores the evolution of peripheral coarse grain (PCG) structure during annealing and solution treatment by metallographic observation and electron back-scattered diffraction (EBSD) of materials in the extruded state, after different annealing heat treatments and different solution treatments. It was found that recrystallization occurred in the surface layer of the material during the extrusion process, and the recrystallized grains developed into PCG during the solution process. The PCG was smaller when the annealing temperature was too low, or the solution temperature was too high, but the PCG structure was thicker. The annealing time had no significant effect on the PCG structure. The coarse grains appeared first at the edge of the material and then engulfed each other to develop into several huge grains.
Effect of pulling speed on directional solidification structure of the single crystal blade
Authors: Zhao Xiao Yun , Cao Guo Qiang
Published: August 2023

In this paper, the influence of withdraw speed on the directional solidification structure of the single crystal blade was studied. The influence of 2.7 mm/min, 5.4 mm/min, and 9.5 mm/min drawing speed on temperature field, temperature gradient, and microstructure were analyzed. The results show that as the casting speed increases, the temperature gradient G decreases, the degree of downward depression of the temperature field also increases, and more stray grains appear at the single crystal blade platform. In addition, it is also found that the increase in the withdrawal speed helps to reduce the secondary dendrite arm spacing and refine the grains. This paper provides a theoretical basis for optimizing the directional solidification process of single crystal blades.
Study on the influence of pre-stretching degree on the strength and microstructure evolution of an Al-Cu-Li alloy
Authors: Li Changlin , Zhang Yongan , Xun Chenyang , Zhu Kai , Chen Pengcheng
Published: August 2023

Al-Li alloys can be strengthened by pre-stretching before artificial aging to promote the precipitation of the strengthened phase. This study investigates the mechanical properties and evolution of a 2 mm thick Al-Cu-Li alloy sheet’s microstructure with various pre-stretching degrees. From the results, as the degree of pre-stretching is increased, the strength gradually increases. Particularly noticeable is the upward trend in yield strength. By the pre-stretching volume of 4%, tensile strength can be enhanced by 95 MPa and yield strength by 187 MPa. Pre-stretching leads to a gradual reduction in precipitation of θ′, an increase in T1 phase number density but a reduction in T1 phase diameter. Meanwhile, a combination of strain-hardening and precipitation-strengthening determines the yield strength. Increasing the pre-stretching degree increases strain-hardening, while T1 phase strengthening decreases gradually.
Design of a Mobile Manipulator for Curtain Wall Installation
Authors: Gao Zhenzhou , Li Yang , Zhu Xiaoliu , Xiao Ming , Liu Hui , Wei Bo
Published: August 2023

The installation of the high-altitude curtain wall is mainly completed manually with simple mechanical assistance. The construction process is characterized by high labor intensity, high risk, low efficiency and low quality. To improve the automation and intelligence of curtain wall installation, improve construction efficiency and reduce labor intensity, a mobile manipulator for curtain wall installation is developed. Firstly, the curtain wall installation process is analyzed. Secondly, kinematics modeling is established, and the forward and inverse kinematics are analyzed and solved. Finally, the experiment is carried out to complete the tasks of grasping, rolling over and transporting stone, glass, ALC plate and other dense and semi-dense materials.
Preparation process optimization and characterization of Litinan-based drug delivery system
Authors: Yang Yang , Song Zifan , Qi Weiguo , Zhang Ningning , Gao Ying , Song Yimin
Published: August 2023

Adriamycin is an antitumor antibiotic, but its systemic side effects and large adverse effects in clinical application limit its wide application. In this study, we prepared Lentinan-oleic acid polymers by esterification reaction and optimized their preparation process by response surface methodology. ADM/LNT-OA micelles were prepared by self-assembly to alleviate the side effects associated with drug administration. The morphology and performance measurements of ADM/LNT-OA were investigated by particle size potentiometry, fluorescence spectroscopy, scanning electron microscopy, and transmission electron microscopy. The results showed that the reaction between Lentinan and oleic acid at pH 7 for 16 h at 25 °C was the best preparation condition for LNT-OA, and the degree of substitution of Lentinan could reach 53.6% with 97.5% yield. The ADM/LNT-OA micelles were spherical micelles of 164.2±11.4 nm with a potential of -30.9±1.5 mV, and their critical micelle concentration was 0.063 mg. In summary, our results suggest that the ADM/LNT-OA drug delivery system provides a basis for improving the efficacy and reducing the toxic side effects of the antitumor drug ADM.