bluuebunny/crossref_metadata_2025 huggingface dataset:
Modified advection upstream splitting method: Revolutionizing accuracy and convergence speed in low-Mach flows
Authors: Mohammadi Adnan , Djavareshkian Mohammad Hassan
Published: October 2023

The vital role of the numerical scheme is becoming increasingly critical as the use of computational fluid dynamics grows. To address the unfavorable effects experienced in low-speed flows when using the AUSM+M scheme (Improved Advection Upstream Splitting Method), the present paper presents an improved approach known as Modified-AUSM+M (M-AUSM+M). This novel method offers enhanced reliability in simulating low-Mach number flows, effectively mitigating the challenges associated with low-speed symptoms encountered in the original AUSM+M scheme. The novel scheme is facilitated by the parameter-free form of the pressure diffusion term in the mass flux and the low-dissipative form of the velocity diffusion term in the pressure flux. The impacts of these critical ingredients are then thoroughly evaluated, and the different characteristics are explored in terms of robustness and accuracy using a wide range of low-Mach test cases. The proposed scheme maintains a consistent correlation between accuracy and convergence speed. In addition, the recently devised technique demonstrates superior accuracy compared to AUSM+M and AUSM+UP schemes when dealing with low-Mach flows. Furthermore, the findings indicate an incredible reduction in iteration numbers, ranging from 30% to 80%, by employing the enhanced scheme in low-Mach domains. In the investigation of high-Mach test cases, the newly developed method preserves the accuracy achieved by AUSM+M in high-Mach flows.
Insights into electronic and transport properties of phosphorene nanorings in two perpendicular directions: Effects of circular and elliptical external potentials
Authors: Bazrafshan M. Amir , Khoeini Farhad , Szafran Bartlomiej
Published: October 2023

In this work, we study the electronic and transport properties of phosphorene nanorings in two perpendicular directions (zigzag and armchair directions) in the presence of a zigzag metallic source and drain leads. Our results are based on the non-equilibrium Green’s function method and a five-parameter tight-binding approach. We investigate how system parameters affect the electronic transport. These parameters include the radius of the rings, the width of the leads, and the external potential. Our results show that for all configurations studied, a transport energy gap exists whose size can be tuned by the width of the leads and the radius of the nanoring. The transmission function of wider leads shows more sensitivity to the variation of the inner radius due to higher electronic states that can respond to smaller changes in the scattering region. In addition, the transport along the armchair direction is more susceptible to tuning than the transport along the zigzag direction. The effects of external potentials on the conductance are more pronounced than the geometrical parameters. In particular, the circular potential of the amplitude of 0.1 eV can widen the transport gap by about ∼0.35 eV.
Propagation properties of the Pearcey Gaussian vortex electron plasma wave
Authors: Wang Jingze , Lu Zhili , Tu Jialong , Huang Zhichong , Deng Dongmei
Published: October 2023

In this Letter, we present an analytical discussion about the propagation properties of the Pearcey Gaussian vortex electron plasma (PGVEP) wave in an unmagnetized, collision-free plasma. Specifically, we examine the intensity, potential, energy flow density, and angular momentum density of the wave. Our findings reveal that the PGVEP wave exhibits the property of self-focusing, and intriguingly, it also demonstrates self-acceleration. Furthermore, we investigate the influence of the topological charge on the aforementioned propagation characteristics, considering the cases when the charge is n = 1 and n = 2, respectively.
Study of the energy spectrum of a few one-dimensional and quasi one-dimensional lattices through tight binding and density functional theory
Authors: Gupta Tribikram , Sharma Kalpana , M Lavanyaa , Gupta Sanjay
Published: October 2023

A graphene nanoribbon (GNR) is a strip of carbon atoms having sp2 hybridization. It has wide application in nanoelectronics and opto-electronics. Usual fields of application are found in field effect transistors, interconnects, logic gates, sensors, energy storage, and photovoltaics. A single unit graphene nanoribbon is a long strip of graphene rings. Such a GNR structure may be seen as two one-dimensional carbon chains that are suitable connected with bonds. We have done tight binding calculations and density functional theory simulation of carbon chains. We study the single bond and double bond one-dimensional carbon chain and the alternate bond (t1-t2), also called a bond order system in one dimension and quasi one-dimensional chain. We find evidence for the emergence of multiple gaps in the energy spectrum of these systems. We have mapped the alternate bond system to the Su–Schrieffer–Heeger model (with a small modification) in one dimension and quasi one dimension. This is the first time such a mapping has been attempted and a comprehensive theoretical and computational study of these chains has been performed.
Flow field reconstruction in inlet of scramjet at Mach 10 based on physical information neural network
Authors: Guo Mingming , Le Jialing , Deng Xue , Tian Ye , Ma Yue , Tong Shuhong , Zhang Hua
Published: October 2023

This paper proposed the physical information residual spatial pyramid pooling (PIResSpp) convolutional neural network that is highly robust and introduces a residual neural network architecture that can satisfactorily fit high-dimensional functions by using jumping connections to reduce the risk of overfitting. Key features of the flow field were extracted by using pooling kernels of different sizes and were then stitched together to fuse its local and global features. The axisymmetric inlet of the scramjet generated by the Bezier curve was established through highly precise numerical simulations, and datasets of flow fields under different geometric configurations were constructed according to the parametric design. The PIResSpp model was trained on a sample dataset, and mapping relationships were established between the parameters of incoming flow/those of the geometry of the inlet, and the velocity, pressure, and density fields in it. Finally, the results of reconstruction of the flow field at the inlet with different design parameters were tested and compared with the outcomes of various deep learning models. The results show that the average peak signal-to-noise ratio of the flow field reconstructed by the proposed model was 36.427, with a correlation coefficient higher than 97%.
Establishment and validation of a viscous-potential coupled and graphics processing unit accelerated numerical tank based on smoothed particle hydrodynamics and high-order spectral methods
Authors: Lyu Hong-Guan , Sun Peng-Nan , Yang Jun-Cheng , Liu Pu-Zhen , Xie Chun-Mei , Ye Yong-Lin
Published: October 2023

The smoothed particle hydrodynamics (SPH) method is an entirely Lagrangian and truly meshless numerical tool that is inherently suitable for simulating violent viscous free-surface flows, whilst it usually renders considerable simulation time when solving large-scale engineering problems. The high-order spectral (HOS) method is an accurate and very efficient numerical tool for modeling a large-scale inviscid gravity wave field, whilst it is hard to tackle complex physical phenomena due to the dependence on the potential flow theory. This paper aims to propose a viscous-potential coupled and graphics processing unit accelerated numerical model for establishing a high-fidelity and high-efficiency numerical wave tank. In this coupling scheme, the SPH method is applied in the near-field where violent physical processes exist to accurately capture complex free-surface behaviors such as overturning and breaking, whilst the HOS method is applied in the far-field where the water undergoes gentle motion to efficiently generate a desired gravity wave. A dedicated SPH–HOS coupling interface is also presented to accurately transmit the flow information from the HOS side to the SPH side. Meanwhile, an SPH–HOS buffer region with several key techniques is also proposed to ensure a successful coupling between the two numerical methods. Different benchmarks demonstrate that the present SPH–HOS coupling method absorbs the respective advantages of the two numerical methods and shows great feasibility and reliability in solving hydrodynamic problems involving gravity wave generation, propagation, deformation, and its interaction with marine structures.
Ferrofluid drops-based actuator in a narrow gap
Authors: Wu Jin-Lin , Chu Hong-Yu
Published: October 2023

Directional transport of a liquid is an important issue in microfluidic systems and application purpose. Here, through combining the ideas of pressure-driven gas bubble-induced acoustic streaming flow and magnetic field-deformed ferrofluid drop, we study the ambient flow induced by an oscillating ferrofluid drop as an in situ actuator in a millimeter-sized gap environment. A drop squeezed by two parallel glass sheets, under the influence of a magnetic field, is discovered to undergo multimodal oscillations. The particle image velocimetry technique helps us to reveal the vortex-typed flow structure surrounding the oscillating drop. The shape changes of drop are found including the circular, elliptical, triangular, inverse-triangular, and circular shapes. We employ the numerical front-tracking method and analytical mixed-mode model to elucidate a drop-driven flow. We find that the pulsating, translational, and quadrupole mode oscillation of the drop is capable to describe most features of the flow distribution. Furthermore, we demonstrate an in situ pump by applying a spatially non-uniform pulsating magnetic field onto the arranged ferrofluid drops. The ferrofluid drop-based in situ pump shows the ability to produce a flow rate of 108 μl/min, which should be a great help in microfluidic pumping.
High temperature annealing of n-type bulk β-Ga2O3: Electrical compensation and defect analysis—The role of gallium vacancies
Authors: von Bardeleben H. J. , He Gaohang , Wu Ying , Ding Sunan
Published: October 2023

The effect of high temperature annealing under O2 and N2 atmospheres on the electrical properties and defect formation on Sn doped n-type β-Ga2O3 bulk samples was investigated by electron paramagnetic resonance (EPR) spectroscopy. EPR, being a volume sensitive technique, probes the entire sample volume. Our results show an electrical compensation being correlated with the formation of a negatively charged Ga vacancy defect VGa2−. This VGa center is different from the one observed after particle irradiation. The associated shift of the Fermi level reveals the presence of Fe3+, Cu2+, and Cr3+, which are residuals related to the growth conditions. The 1100 °C N2 annealed sample is fully compensated, and the neutral donor resonance is no longer observed. Our results directly confirm the thermal instability of Ga and Sn in n-type conducting samples. No oxygen vacancy related centers were detected. We discuss the various Ga vacancy centers reported previously.
Quantum mechanics based non-bonded force field functions for use in molecular dynamics simulations of materials and systems: The nitrogen and oxygen columns
Authors: Geng Peng , Zybin Sergey , Naserifar Saber , Goddard William A.
Published: October 2023

Accurate Force Fields (FFs) are essential for Molecular Dynamics (MD) simulations of the dynamics of realistic materials in terms of atomic-level interactions. The FF parameters of short-range valence interactions can be derived through Quantum Mechanical (QM) calculations on model systems practical for QM (<300 atoms). Similarly, the dynamic electrostatic interactions can be described with methods such as QEq or PQEq that allow charges and polarization to adjust dynamically. However, accurately extracting long-range van der Waals (vdW) interactions from QM calculations poses challenges due to the absence of a definitive method to distinguish between the different energetic components of electrostatics, polarization, vdW, hydrogen bonding, and valence interactions. To do this we use the Perdew–Burke–Ernzerhof flavor of Density Functional Theory, including empirical D3 vdW corrections, to predict the Equation of State for each element (keeping any covalent bonds fixed), from which we obtain the two-body vdW nonbond potential. Here, we extend these calculations to include non-bonded parameters for the N and O columns of the periodic table so that we now describe columns 15 (N), 16 (O), 17 (F), and 18 (Ne) of the periodic table. For these 20 elements, we find that the two-body vdW potentials can all be mapped to a single universal two-body curve, with just three scaling parameters: Re, De, and L. We refer to this as the Universal NonBond (UNB) potential. We expect this to be useful for new MD simulations and a helpful starting point to obtain UNB parameters for the remainder of the periodic table.
Sulfur-graded kesterite structured film drives improvement of VOC
Authors: Wang Siyu , Liu Yue , Shen Zhan , Zhang Huamei , Wu Li , Li Juan , Liu Fangyang , Zhang Yi
Published: October 2023

Realizing the graded bandgap in absorber layer is very essential for high efficient thin film solar cells. However, such bandgap modification in kesterite-structured Cu2ZnSnSe4 is normally realized via high temperature sulfurization process (above 500°C), which is not only difficult to control the sulfurization depth, but also introduces additional deep defects because of the decomposition of absorber layer at such high temperature. In this study, a low-temperature sulfurization process (150°C) is developed. Such process not only inhibits the decomposition of Cu2ZnSnSe4 films and controls the elemental distribution very well, but also increase the surface bandgap of the absorber layer and form a gradient energy bandgap. Also, the density of deep-level defects in the Cu2ZnSnSe4 layer is reduced. As a consequence, the open circuit voltage of the solar cell is improved by 60 mV. This study paves the way towards the high efficient kesterite solar cell and other solar cells.
Demonstration of near-ideal Schottky contacts to Si-doped AlN
Authors: Quiñones C. E. , Khachariya D. , Bagheri P. , Reddy P. , Mita S. , Kirste R. , Rathkanthiwar S. , Tweedie J. , Pavlidis S. , Kohn E. , Collazo R. , Sitar Z.
Published: October 2023

Near-ideal behavior in Schottky contacts to Si-doped AlN was observed as evidenced by a low ideality factor of 1.5 at room temperature. A temperature-independent Schottky barrier height of 1.9 eV was extracted from temperature-dependent I–V measurements. An activation energy of ∼300 meV was observed in the series resistance, which corresponded to the ionization energy of the deep Si donor state. Both Ohmic and Schottky contacts were stable up to 650 °C, with around four orders of magnitude rectification at this elevated temperature. These results demonstrate the potential of AlN as a platform for power devices capable of operating in extreme environments.
Photonic spin Hall effect in twisted bilayer phosphorene
Authors: Xia Yu , Liu Jiaming , Zhou Renlong
Published: October 2023

We investigate the photonic spin Hall effect of a linearly polarized Gaussian beam reflected on the surface of twisted bilayer phosphorene. The photonic spin shift depends strongly on optical resonance behavior, which is determined by the twist angle. The magnified spin shift near the Brewster angle is sensitive to the twist angle and can be fitted by numerical models. In particular, the spin shifts in the terahertz region of frequency are well within the current experimental detection precision. Our findings suggest that the photonic spin Hall effect is promising for precise characterization of the optical property and the structure of twisted bilayer phosphorene.
Harmonic balance simulation of the influence of component uniformity and reliability on the performance of a Josephson traveling wave parametric amplifier
Authors: Zheng 郑 Yuzhen 煜臻 , Xiong 熊 Kanglin 康林 , Feng 冯 Jiagui 加贵 , Yang 杨 Hui 辉
Published: October 2023

A Josephson traveling wave parametric amplifier (JTWPA), which is a quantum-limited amplifier with high gain and large bandwidth, is the core device of large-scale measurement and control systems for quantum computing. A typical JTWPA consists of thousands of Josephson junctions connected in series to form a transmission line and hundreds of shunt LC resonators periodically loaded along the line for phase matching. Because the variation of these capacitors and inductors can be detrimental to their high-frequency characteristics, the fabrication of a JTWPA typically necessitates precise processing equipment. To guide the fabrication process and further improve the design for manufacturability, it is necessary to understand how each electronic component affects the amplifier. In this paper, we use the harmonic balance method to conduct a comprehensive study on the impact of nonuniformity and fabrication yield of the electronic components on the performance of a JTWPA. The results provide insightful and scientific guidance for device design and fabrication processes.
Compact generation scheme of path–frequency hyperentangled photons using 2D periodical nonlinear photonic crystal
Authors: Chen 陈 Yang-He 洋河 , Ji 季 Bo 波 , Li 李 Nian-Qin 念芹 , Jiang 姜 Zhen 震 , Li 李 Wei 维 , Li 李 Yu-Dong 昱东 , Feng 冯 Liang-Sen 梁森 , Wu 武 Teng-Fei 腾飞 , He 何 Guang-Qiang 广强
Published: October 2023

Hyperentanglement is a promising resource for achieving high capacity quantum communication. Here, we propose a compact scheme for the generation of path–frequency hyperentangled photon pairs via spontaneous parametric down-conversion (SPDC) processes, where six different paths and two different frequencies are covered. A two-dimensional periodical χ
(2) nonlinear photonic crystal (NPC) is designed to satisfy type-I quasi-phase-matching conditions in the plane perpendicular to the incident pump beam, and a perfect phase match is achieved along the pump beam’s direction to ensure high conversion efficiency, with theoretically estimated photon flux up to 2.068 × 105 pairs⋅s−1⋅mm−2. We theoretically calculate the joint-spectral amplitude (JSA) of the generated photon pair and perform Schmidt decomposition on it, where the resulting entropy S of entanglement and effective Schmidt rank K reach 3.2789 and 6.4675, respectively. Our hyperentangled photon source scheme could provide new avenues for high-dimensional quantum communication and high-speed quantum information processing.
Optimal and robust control of population transfer in asymmetric quantum-dot molecules
Authors: Guo 郭 Yu 裕 , Ma 马 Songshan 松山 , Shu 束 Chuan-Cun 传存
Published: October 2023

We present an optimal and robust quantum control method for efficient population transfer in asymmetric double quantum-dot molecules. We derive a long-duration control scheme that allows for highly efficient population transfer by accurately controlling the amplitude of a narrow-bandwidth pulse. To overcome fluctuations in control field parameters, we employ a frequency-domain quantum optimal control theory method to optimize the spectral phase of a single pulse with broad bandwidth while preserving the spectral amplitude. It is shown that this spectral-phase-only optimization approach can successfully identify robust and optimal control fields, leading to efficient population transfer to the target state while concurrently suppressing population transfer to undesired states. The method demonstrates resilience to fluctuations in control field parameters, making it a promising approach for reliable and efficient population transfer in practical applications.
Generating attosecond pulses with controllable polarization from cyclic
H32+
molecules by bichromatic circular fields
Authors: Zhang 张 Si-Qi 思琪 , Zhang 张 Bing 冰 , Yan 闫 Bo 博 , Jiang 姜 Xiang-Qian 向前 , Sun 孙 Xiu-Dong 秀冬
Published: October 2023

We investigate the polarization properties of harmonics from the cyclic

H
3

2
+

molecular ions in tailored bichromatic counter-rotating circularly polarized (BCCP) fields by solving the time-dependent Schrödinger equation. The allowed harmonics and their helicities are associated with the symmetry compatibility of the field-target systems, and large intensity difference between adjacent harmonics with opposite helicities appears in a wide spectral range when the BCCP field is at certain rotation angles. We try to explain the intensity difference by using a recombination model based on the quantum-orbit theory and by analyzing the ionization pathways. Moreover, to synthesize attosecond pulse trains with tunable polarization, the intensity difference is manipulated by introducing a seed XUV field, and by changing the relative amplitude ratio as well as the helicity of BCCP fields.
Rhythmic temporal prediction enhances neural representations of movement intention for brain–computer interface
Authors: Meng Jiayuan , Zhao Yingru , Wang Kun , Sun Jinsong , Yi Weibo , Xu Fangzhou , Xu Minpeng , Ming Dong
Published: October 2023

Objective. Detecting movement intention is a typical use of brain–computer interfaces (BCI). However, as an endogenous electroencephalography (EEG) feature, the neural representation of movement is insufficient for improving motor-based BCI. This study aimed to develop a new movement augmentation BCI encoding paradigm by incorporating the cognitive function of rhythmic temporal prediction, and test the feasibility of this new paradigm in optimizing detections of movement intention. Methods. A visual-motion synchronization task was designed with two movement intentions (left vs. right) and three rhythmic temporal prediction conditions (1000 ms vs. 1500 ms vs. no temporal prediction). Behavioural and EEG data of 24 healthy participants were recorded. Event-related potentials (ERPs), event-related spectral perturbation induced by left- and right-finger movements, the common spatial pattern (CSP) and support vector machine, Riemann tangent space algorithm and logistic regression were used and compared across the three temporal prediction conditions, aiming to test the impact of temporal prediction on movement detection. Results. Behavioural results showed significantly smaller deviation time for 1000 ms and 1500 ms conditions. ERP analyses revealed 1000 ms and 1500 ms conditions led to rhythmic oscillations with a time lag in contralateral and ipsilateral areas of movement. Compared with no temporal prediction, 1000 ms condition exhibited greater beta event-related desynchronization (ERD) lateralization in motor area (P< 0.001) and larger beta ERD in frontal area (P< 0.001). 1000 ms condition achieved an averaged left–right decoding accuracy of 89.71% using CSP and 97.30% using Riemann tangent space, both significantly higher than no temporal prediction. Moreover, movement and temporal information can be decoded simultaneously, achieving 88.51% four-classification accuracy. Significance. The results not only confirm the effectiveness of rhythmic temporal prediction in enhancing detection ability of motor-based BCI, but also highlight the dual encodings of movement and temporal information within a single BCI paradigm, which is promising to expand the range of intentions that can be decoded by the BCI.
A review on flexural behavior of reinforced concrete beams strengthened with prestressed carbon fiber reinforced polymer plates
Authors: Tang Weibai
Published: October 2023

In recent years, with the rapid development of China’s economy, reinforced concrete structure as an economical and good mechanical properties material, is widely used in buildings. In bridge engineering, Carbon Fiber Reinforced Polymer materials is mostly used as externally bonded reinforcement for flexural strengthening of reinforced concrete (RC) beams. However, this method makes the strength of CFRP plates cannot be fully utilized, while the prestressed technology can significantly improve the efficiency of CFRP materials and the flexural strength of the RC beams. This paper compares different methods of prestressed CFRP plates strengthening RC beams and discuss the development of the technology. The results shows that RC beams strengthened with prestressed CFRP plates have better flexural performance. The cracking, yield and ultimate loads increase significantly compared with ordinary beams or non-prestressed strengthened beams. The effectiveness of strengthening process are related to many factors ranging from anchorage methods, prestress levels, ratio of corrosion to bond length. Future research suggestions are also given. At present, most of the experiments are operated in ordinary environment, which is different from the project in real life. More testing environment like chlorine corrosion must be considered. The trials about prestress loss during strengthening process are not enough. There also need more comparative trials in prestressed CFRP plates strengthening concerning prestress loss and non-prestressed CFRP plates.
Research on the effect of sand content on stress and durability of cement
Authors: Lin Yuquan
Published: October 2023

With the progress of science and technology and the improvement of people’s quality of life, the demand for materials is getting higher and higher. As one of the most important civil engineering materials, concrete is widely used to repair a large number of broken infrastructures. Its production uses sand and aggregate from quarrying operation. If the use is unreasonable, a large amount of waste will be produced. In addition, there is a significant shortage of natural building raw materials in many regions (especially in developed regions). So improving the sustainability and durability of concrete materials can save transportation costs. This paper mainly discusses the influence of sand content in cement concrete on the performance of the material itself. The maximum pressure resistance of the corresponding specimen is measured by the pressure sensor and other experimental instruments, and compared with the specimen of different shape and volume under the condition of different sand rate. By changing the ambient temperature, the number of times that the specimen does not conform to the specified standard value is measured, and the durability of the specimen with different sand ratio is obtained. In this work, the optimal sand gravel ratio is successfully and relatively accurately measured. And it can be reasonably used in infrastructure construction.
Recent research of materials for emissive layer of OLED
Authors: Huang Yongqi
Published: October 2023

As time has gone on, a lot of changes in display technology have taken place. Organic light-emitting diode (OLED) is the one of the many types of display technology. They have attracted many interests in the academic filed and commercial worlds, and developed rapidly since their earliest introduction. They are now highly regarded and used in the display and lighting industries due to a number of promising characteristics, such as environmentally friendly, high energy efficiency, large area, light weight, and thin shape. Among various light emitting materials, polymers have higher glass transition temperature. Therefore, polymer-based OLEDs exhibit higher stability and have received wide attention. The development of OLED devices can be divided into three main generations of emitter materials based on the technique of the emissive layer of OLEDs. The first generation of OLED is fluorescent OLED (FOLED), the second generation is phosphorescent OLED (POLED), and the third generation is thermally activated delayed fluorescence (TAFD). In this article, device structure, mechanism and development of polymer-based OLEDs are introduced. Specifically, working principles and materials of the three generations are presented with a focus on TADF-based OLEDs. In addition, their device performances including quantum efficiency and lifetime are compared quantitatively.
Application of graphene as sensors: a review
Authors: Wang Yidi
Published: October 2023

Graphene is a modern material which is currently also a topic in great demand. It has some special characteristics like being super thin, high conductivity, highly flexible, and more. These specialities made graphene a genuine material for developing new sensors. Although graphene is relatively rare in commercial use due to the lack of a wide-range and low-cost production method, many laboratory-based research and studies have already developed excellent sensors using graphene in many fields. After analysing masses of articles, this synthesised review concluded the application of graphene as electrical sensors, indicating the future. This paper finds that based on the physical character of graphene, it is also commonly made to be physical sensors in many perspectives, like measuring pressure, strain, temperature, humidity and even magnetic field strength (using the quantum Hall Effect) and many more. Those sensors are showing extraordinary performance; however, they lack stability under severe environments. Also, more compositive graphene material could be developed to expand the scope of electrochemical sensing. The flexibility of graphene is also under consideration which contains high potential in medical fields by designing wearable sensing systems.
From synthesis to modification - a series of optimization strategies for hydrogels as drug delivery carriers
Authors: He Ziyu
Published: October 2023

In recent years, hydrogels have been gradually used in the fields of biochemistry and medicine due to their unique structure and properties. Particularly, it plays an important role in the application of tissue stents, coating material and drug delivery systems. However, a major problem with these kinds of application is that they can not satisfy some complex requirements due to their limitations such as poor mechanical properties and lack of specific responsiveness. This study aims to provide a set of feasible modification methods to obtain a hydrogel with better performance in all aspects. The blended hydrogel material and semi-interpenetrating network structure are adopted to enhance the mechanical properties of the product and achieve controllability initially. Moreover, the combination of multi-response hydrogels and 3D printing technology is conducive to manufacturing multilayer smartness hydrogels with high functionality and high controllability in a short period at a low cost. The techniques mentioned in this paper can be used in combination to improve the performance of target products and a set of strategies for realizing smart hydrogel is formed. This paper introduces the current status of advanced hydrogel and the development tendency of this material in the future, which provides a theoretical background for the research direction of hydrogel in drug delivery systems for other scholars.
Recycling of homogenous catalyst using organic solvent filtration and electrochemical separation
Authors: Li Jiawei
Published: October 2023

Homogenous catalyst has great selectivity and kinetic advantages. However, it is quite difficult to recover because it has same phase as the reaction mixture, so their utilization is being limited. A popular method to recover the catalyst is organic solvent nanofiltration, which use the transmembrane pressure and the different composition of the solvents to achieve the catalyst recovery. In recent research, a new method-separation using electrochemistry had been discovered which seems to increase the recovery percentage. In this paper, both strategies with recent developments are summarized, and focused on how the accompanied components such as solvents, electrolytes and electrode usage will influence the catalyst recovery.
A brief review of nanotechnology
Authors: Zhou Mingyu
Published: October 2023

It has been almost 50 years since the concept of nanotechnology was proposed, and it has had a significant impact on our society over the years. In this article, the development of nanotechnology will be briefly summarized. Besides, two main fabrication methods are going to be introduced, including top-down methods and bottom-up methods. Additionally, three typical nanomaterials, including graphene, fullerenes, and carbon nanotubes, are shown, as well as the corresponding preparation methods. What’s more, applications of nanotechnology in environmental protection, food, and agriculture are briefly discussed. It is believed that after decades of effort, nanotechnology will be further developed and have a more profound impact on the development of society. However, there are some problems that need to be fixed, such as the mass production of nanomaterials, the pollution problems and health problems that may occur in the application, etc.
Total synthesis of Oboflavanone B
Authors: Ke Shanwen , Pan Chenghao
Published: October 2023

Oboflavanone B, a revision of Oboflavanone A, has unique structure. Intrigued by its key 2,8-dioxabicyclo(3.3.1)nonane structure and chromanone structure, this paper discussed and reported a proposal towards the synthesis of this product. This work provides a theoretically feasible retrosynthesis, which utilized coupling reactions to connect the two main parts of the natural product. The key strategy of these syntheses involves Heck reactions, Fries rearrangement and addition reactions. To ensure the chiral of the target product, the chiral of the reactant was restricted in this work. The synthesis went through a total 12 steps process, containing 4 steps on protecting and deprotecting reactions. All the substrates given in each step are available in this strategy.
The conversion of carbon dioxide to methanol simulated by aspen plus
Authors: Wang Litong
Published: October 2023

The industrial anthropogenic emissions of the greenhouse gas, carbon dioxide (CO2) have surged over the past century. The unconscious emission of carbon dioxide into the environment leads to the greenhouse effect and causes global warming. The cement industry is regarded as one of the major sources of carbon dioxide emissions recently, numerous companies decide to construct relevant installations for mitigating the severe pollution caused by CO2. HeidelbergCement, a multinational building materials company, is also conscious of the issue and concentrates on the capture, usage, and storage of CO2 (CCUS). Apart from the direct use, the captured CO2 has the possibility to become a promising business. In the paper, one of the technologies that convert CO2 into methanol by hydrogenation is presented and simulated with the program named Aspen Plus. The improvements based on the purer output and energy saving on the initial simulation were accomplished. After purifying the solution, there is a rise in the concentration of CH3OH from 96.0%wt to 99.97%wt, which is an exceptionally high level that could be employed for spectroscopic or semiconductor applications. This paper may offer some references for the future studies of CCUS.
Damping Effect on Instability of Pressure Relief Valve Used for Cargo Venting System
Authors: Hu Jie , Zhou Haili , Huang Changan , Wan Ran , Wang Ji
Published: October 2023

A mathematical model for predicting an unstable working condition called cycling of a pressure relief valve controlled by weight and spring is proposed. The valve is connected to a reservoir used to store liquid cargo by a long pipe. A transient, compressible and one-dimensional fluid dynamic equation in the pipe is numerically solved, with boundary conditions given by the valve and reservoir dynamics. The effect of valve moving part damping coefficient is analysed, which can be changed by adding dampers. Installing a damper may solve the cycling problem for weight-loaded and spring-loaded pressure relief valves. The damping coefficient of the installed damper should be carefully selected, especially for spring-loaded valves. Too large damping coefficient may cause overpressure in the reservoir when the valve opens and too low pressure when the valve closes. After all, installing damper is a theoretically possible way to prevent cycling occurrence when the pipe length is too long in some practical situations.
Analysis of Cavitation Flow Performance in Centrifugal Pump Using OpenFOAM
Authors: Huang Si , Hu Yuxiong , Wei Yifeng , Mo Yushi
Published: October 2023

In order to explore the cavitation mechanism and cavitation cloud development process of centrifugal pump, OpenFOAM7.0 open-source software was used to simulate the unsteady cavitation gas-liquid two-phase flow of IS125 centrifugal pump under different flow conditions. Based on the flow field simulation results, the relationship between the flow rate of the centrifugal pump and the NPSHr was predicted and compared with the experimental data. The comparison showed that it is feasible to use OpenFOAM software to simulate the cavitation flow of centrifugal pump under design condition. Under the design condition, when NPSHa was different, the distribution of cavitation clouds in each blade channel was asymmetric. With the decrease of NPSHa, cavitation clouds continue to develop downstream in the impeller channel and appear on the blade pressure surface. Regardless of whether cavitation occurred in the centrifugal pump, the pressure coefficient showed periodic pulsation, and the pulsation number of the impeller in a rotation cycle was equal to the number of blades of the impeller. The research results can provide an effective open-source software calculation method for centrifugal pump performance prediction.
Research on Vibration Test Method of Hydrogen System in Fuel Cell Bus
Authors: Guo Ting , Xu Yue , Wang Guozhuo , Wu Shiyu , Wu Zhen , Wang Zhijun , Liang Rongliang , Zhou Mingyue , Wang Fang
Published: October 2023

As one of the important structures of fuel cell vehicles, the on-board hydrogen system provides certain fuel for the electrochemical reaction of fuel cell stacks. During the operation of the vehicle, it is necessary to ensure that the on-board hydrogen system does not leak during the vibration process. This paper collects the load spectrum of a commercial vehicle running on the actual social road surface, extrapolates the road load spectrum of the whole life cycle, and establishes a vibration test method for the platform of the on-board hydrogen system based on the principle of user correlation. Taking a bus as an example, this paper introduces the designated route and the result of the method in detail. Through the calculation of equal damage, a more reasonable bench acceleration verification method is established. This method can effectively verify the anti-vibration performance of vehicle hydrogen system and provide certain support for product development.
Numerical Study on the Effect of Partial Delamination of Thermal Barrier Coating on the Cooling Effect of Turbine Blade
Authors: Wang Yuqun , Wang Feilong , Wang Yubin , Zeng Jiawei
Published: October 2023

A localized delamination modeling method based on a thin-wall thermal resistance model is developed in this study. Numerical investigations are then conducted with this model to analyze the influence of factors such as the position, area, shape, and depth of localized delamination on blade cooling efficiency. Firstly, the simulation results of two coating modeling methods (the thin-wall thermal resistance model and the direct modeling method) are examined. Then, the overall insulation efficiency of the blade surface with a complete thermal barrier coating is analyzed based on the thin-wall thermal resistance model. Subsequently, the impact of different delamination factors on blade cooling effectiveness is explored. The research results indicate that compared to the direct modeling method, the thin-wall thermal resistance model has a simulation deviation of less than 7% and can effectively improve modeling and simulation efficiency while ensuring computational accuracy. The highest insulation efficiency of the thermal barrier coating is observed in the middle section of the blade’s back surface near the cold air inlet, reaching 8.3%. Under a constant delamination area, the shape of the localized delamination has a minor effect on blade cooling effectiveness. When more delamination occurs in areas with higher insulation efficiency, the impact on blade cooling effectiveness becomes more significant.
Numerical Study on Drag Reduction Performance of a New Type of Composite Skin
Authors: Guo Hong
Published: October 2023

In order to reduce the surface resistance of underwater vehicles, a new type of composite skin is proposed by combining flexible skin with flexible and miniaturized steel wire vibration isolators. Using ANSYS fluent and transient structure to conduct bidirectional Fluid-structure interaction and drag reduction performance of the skin was studied. The effects of flow velocity and material parameters on its drag reduction performance were discussed. Research results indicate that compared with the steel plate without skin, the resistance of the skin is significantly reduced. Analyzing its mechanism, the wall shear stress after laying the skin is reduced. This study provides a new approach for the design of skin for underwater vehicles.
A New Method for Evaluating Fracability Based on Cluster Analysis and Well Logging Petrophysical Facies Division
Authors: Zhang Xiao , Wei Jianguang , Zhou Xiaofeng , Lin Fengpeng , Liu Shiying , Gayubov Abdumalik , Wu Jie
Published: October 2023

The fracability of rock is a crucial parameter in determining the efficiency of fracturing in tight reservoirs. However, current methods for evaluating fracability have significant limitations. This paper proposes a new method for evaluating reservoir fracability based on cluster analysis of logging petrophysical facies. This method considers rock mechanics characteristics, petrophysical response characteristics, and reservoir physical parameters, among other factors. The Well X of the block was used as the research subject. Using the brittleness index and permeability evaluation index, the reservoir fracability of the target block is classified into five categories: high brittleness and low permeability rock, high brittleness and super low permeability rock, low brittleness and low permeability rock, low brittleness and super low permeability rock, and clay/shale. Geolog software is used to generate fracability prediction profiles for representative wells based on petrophysical facies. To further validate this evaluation method, the fracture construction data and microseismic monitoring interpretation results of Well Y in a tight block of an oil field were synthesized and analyzed to predict its fracability. The overall prediction accuracy reached 81.8%, indicating that the new fracability evaluation method has good application effect.
Study on the Influence of Machining Deviation of Vehicle Automatic Transmission Shifting Control Components on Calibration Parameters
Authors: Yi Chao , Du SongTao , Lei Yan , Qiu Tao
Published: October 2023

An automatic transmission (AT) shift control model was completed by commercial code Simulation X based on AT shift control system mechanism. The AT shift process under condition of varied machining deviation was analysed by virtual calibration method based on this AT shift model. The results show that the machining deviation of AT shifting control component causes effect on the shift quality, especially affecting the shift impact during the shift process. The machining deviation is larger, accordingly the calibrated parameters such as the hydraulic pressure gradient and the control time increase. It is helpful to improve the shift quality to set the suitable calibration parameters of clutch shift according to different machining deviation.
Research on Prediction Model of Interlayer Leakage in Separate Injection Wells in Offshore Oilfields
Authors: Gao Yonghua , Chen Jie , Liu Lei , Bao Chenyi , Liu Huawei , Li Baolong , Shi Shiying
Published: October 2023

In order to ensure effective layered water injection, it is of great significance to establish the functional relationship among the equivalent diameter of damage, leakage and pressure of sealing cylinder. In this paper, the experimental and numerical simulation experiments were carried out to study the relationship between gap flow rate, pressure drop and equivalent diameter of sealing cylinder under the conditions of uniform corrosion, fracture non-uniformity and random groove non-uniform distribution and scratches in different tubing, equivalent diameters and gap widths. Through a lot of data analysis, the relationship between the damage state and the leakage quantity is established and evaluated by physical simulation test. The research shows that the error between the established model function relation and the test data is no more than 10%. By simulating the damage condition of the shock sealing cylinder and quantitatively detecting the defect of the sealing cylinder, the model function relation can well predict the corresponding damage situation. Therefore, this model function can be used to solve sealing cylinder inspection problem, so as to judge the seal defect and leakage quantity which is independent of the experience of the person in charge of the site and able to use the data as a basis for judgment. This research provides a new technology for the effective prediction of the damage of sealing cylinder, and provides theoretical guidance for selecting matching sealing tools and realizing layered mining.
Particle Deposition Characteristics on Turbine Blade Surface Based on Critical Velocity Model
Authors: Zeng J W , Wang F L , Wang Y Q , Wang Y B , Shi J
Published: October 2023

Based on the critical velocity model of EI-Batsh, this paper further considered the particle deposition-bounce and the secondary collision deposition after the bounced, which improved the original particle deposition model. Then the particle deposition mass per unit of time and area (PDM) was proposed to characterize the particle deposition on the turbine blade surface. The effects of different rows of cooling film holes, blowing ratios, particle diameters and diameters of cooling film holes on the particle deposition characteristics of the blade surface were then investigated. The results show that the deposition amount of the single cooling film holes opening with radial inclination facing the leading edge is the smallest, and the deposition amount gradually increases when the inclination angle is shifted toward the pressure and suction surface. As the blowing ratio increases from 0.3 to 1.5, the amount of particle deposition tends to decrease and then increase, and reaches a minimum value when the blowing ratio is about 0.5. The deposition increases with increasing particle diameters in the range of 2-10 μm and gradually increases when the diameter of cooling film holes is from 0.99 mm to 1.5 mm.