bluuebunny/crossref_metadata_2025 huggingface dataset:
A new method for age-dating the formation of bars in disc galaxies
Authors: de Sá-Freitas Camila , Fragkoudi Francesca , Gadotti Dimitri A. , Falcón-Barroso Jesús , Bittner Adrian , Sánchez-Blázquez Patricia , van de Ven Glenn , Bieri Rebekka , Coccato Lodovico , Coelho Paula , Fahrion Katja , Gonçalves Geraldo , Kim Taehyun , de Lorenzo-Cáceres Adriana , Martig Marie , Martín-Navarro Ignacio , Mendez-Abreu Jairo , Neumann Justus , Querejeta Miguel
Published: December 2022

The epoch in which galactic discs settle is a major benchmark for testing models of galaxy formation and evolution but remains largely unknown. Once discs settle and become sufficiently self-gravitating, stellar bars are able to form; therefore, determining the ages of bars can shed light on the epoch of disc settling, and on the onset of secular evolution. Nevertheless, timing when the bar formed has proven challenging. In this work we present a new methodology for obtaining the bar age, using the star formation history of nuclear discs. Nuclear discs are rotation-supported structures, built by gas pushed to the centre via bar-induced torques, and their formation is thus coincident with bar formation. In particular, we used integral field spectroscopic data from the TIMER survey to disentangle the star formation history of the nuclear disc from that of the underlying main disc, which enables us to more accurately determine when the nuclear disc formed. We demonstrate the methodology on the galaxy NGC 1433 – which we find to host an old bar that is 7.5−1.1+1.6(sys)−0.5+0.2(stat) Gyr old – and describe a number of tests carried out on both the observational data and numerical simulations. In addition, we present evidence that the nuclear disc of NGC 1433 grows in accordance with an inside-out formation scenario. This methodology is applicable to high-resolution integral field spectroscopic data of barred galaxies with nuclear discs, making it ideally suited for the TIMER survey sample. In the future we will thus be able to determine the bar age for a large sample of galaxies, shedding light on the epoch of disc settling and bar formation.
SMARCB1(INI-1)-Deficient Sinonasal Carcinoma: An Evolving Entity
Authors: Chung Sei Y. , Kenee Parker , Mitton Tanner , Halderman Ashleigh
Published: December 2022

SMARCB1(INI-1)-deficient sinonasal carcinoma is a rare, poorly differentiated neoplasm with a poor prognosis. Though historically most were identified as sinonasal undifferentiated carcinoma, we now understand it to be a distinct entity. There is currently a general consensus supporting multimodal therapy, though the optimal sequence of surgery, chemotherapy, and radiation has yet to be defined.
Effect of mole weight ratio of reaction on propagation of cellular detonations
Authors: Li Haoyang , Yao Kepeng , Yang Ruixin , Wang Chun
Published: December 2022

The propagation of two-dimensional cellular detonations is investigated numerically using a one-step reversible reaction model. The effect of the average mole weight ratio WB/WA of the product and reactant on the one-dimensional Zeldovich–von Neumann–Döring (ZND) detonation and cellular detonation behavior is analyzed in detail. Several interesting cellular detonation phenomena are observed in the numerical simulations. These can be divided into five categories according to the cell patterns of detonation, i.e., regular, relatively regular, irregular, half-cell propagating, and decoupled detonation. The results indicate that differences in cell size under different values of WB/WA modify the cellular detonation behavior. The ZND detonation parameters under various WB/WA values are studied and related to the cell size. The results show that the reaction zone length and maximum heat release rate are clearly influenced by WB/WA. Furthermore, for both ZND detonation and cellular detonation, the reaction zone length decreases as WB/WA increases, which effectively reduces the cell size. To elucidate the effects of the reaction zone length on cell size, thermoacoustic instability theory is introduced to investigate the acoustic perturbations in the reaction zone. This allows the correlation between the propagation frequency and cell number along the width of the duct to be determined. Correlation analysis indicates that the cell number has a strong linear dependence on the perturbation frequency.
Frogs vs fungus: the emergence of amphibian chytridiomycosis
Authors: Webb Rebecca J. , Waddle Anthony W.
Published: December 2022

By the late 1980s, widespread dramatic declines in amphibian populations were causing alarm. The culprit was identified as Batrachochytrium dendrobatidis (Bd), a chytrid fungus that infects the skin of various amphibian hosts, particularly anurans (frogs), and the first example of a chytridiomycete parasitising vertebrates. The disease, chytridiomycosis, has spread globally and is linked to the decline and extinction of many amphibian species. This review summarises the discovery of Bd, its emergence as a panzootic pathogen, and some current mitigation strategies to conserve amphibians.
The effect of pre-exposure prophylaxis (PrEP) on negotiating casual sex between gay men: disclosure, assumptions, and communication
Authors: Kolstee Johann , Prestage Garrett , Philpot Steven , Bavinton Benjamin , Hammoud Mohamed , Keen Phillip , Holt Martin
Published: December 2022

Background The disclosure of HIV status and pre-exposure prophylaxis (PrEP) use can be important in the negotiation of safe sex. With the rapid uptake of PrEP in Australia, norms and expectations about discussion and disclosure may have changed. Methods We explored the disclosure of PrEP use, HIV status and communication with sex partners by HIV-negative gay men in Sydney, Australia. We conducted semi-structured interviews from October 2017 to May 2018 and analysed data using a codebook thematic analysis approach. Results Participants had a variety of expectations of what they should tell their partners and what they expected in return. For some participants, PrEP had negated the need for any discussion about HIV. Many participants assumed their partners would find information about their HIV status or PrEP use on their online profiles or that partners would ask, if necessary. Conclusions Building a stronger, shared understanding among gay men that disclosure and discussion no longer automatically occur before sexual encounters may be useful.
Degrees and grammar
Authors: Luo Qiongpeng , Xie Zhiguo , Li Xiao
Published: December 2022

In this article, we discuss some fundamental issues as well as several unresolved questions of degree-based
theories in contemporary linguistics from the perspective of East Asian languages, with a view to pointing out some directions for
future research. We first focus on several controversies surrounding the studies of comparative constructions in the literature,
i.e., phrasal comparison vs. clausal comparison, individual comparison vs. degree comparison, big DegP vs. small DegP, the points
of cross-linguistic variation, etc. We then expand the discussion to comparative constructions and other degree-related
constructions in Mandarin Chinese, Japanese, and Korean, and demonstrate how an East Asian perspective offers a novel insight into
those controversies and uncovers considerable in-depth commonality underlying a variety of degree-related constructions
cross-linguistically. We conclude by suggesting some directions for future within- and cross-linguistic research.
Editorial: Celebrating the 30 Wonderful Year Journey of Chinese Physics B
Authors: Gao Hong-Jun , Xiong Qihua
Published: December 2022

The year 2022 marks the 30th anniversary of Chinese Physics B. This editorial provides a brief history of the journal and introduces the anniversary theme collection comprising over 30 invited reviews and perspective articles from renowned scholars in various branches of physics.
Numerical simulation study on the influence of scroll design parameters on helicopter intake system
Authors: Liu Xinhui , Yan Yan , Lu Jiping , Han Yafeng
Published: December 2022

Based on the numerical simulation theory, this paper establishes the two-phase flow calculation model of sand and air mixture in the sand control vortex tube, and combined with CFD numerical simulation, studies the influence rules of various design parameters of the vortex tube on the total pressure loss and sand dust separation efficiency of the helicopter intake system, optimizes the structural parameters of the vortex tube separator, and puts forward a set of vortex tube design method, it provides a basis for the design optimization of vortex tube.
Intelligent Cooling Devices for Truck’s Brake System
Authors: Li Teng
Published: December 2022

Many domestic traffic accidents are caused by high-temperature friction of truck’s brake drum resulting in failure of brake system. Therefore, it is the key to solve the problem of decline on brake drum performance caused by temperature. The following schemes are mainly adopted: improving brake structure and friction materials, adding auxiliary brake devices, and installing cooling devices for brake system. This paper summarizes the structure and characteristics of most intelligent cooling devices for brake system in China. In addition, based on these intelligent cooling devices, the paper also puts forward new intelligent cooling devices for truck’s brake system. The system uses sensors to analyze the temperature state of the brake drum. According to the analysis results, the central controller innovatively combines air pump and water pump to transform low-pressure water into high-pressure water, and then sprays and cools the brake drum through the water pipes and arc spray devices to ensure the normal operation of the brake system.
Design of chopper operational amplifier for leakage current protector chip
Authors: He Congrong , Wu Chenjian
Published: December 2022

Due to the low frequency and small amplitude of the input signal of the leakage current protection chip, an operational amplifier with low offset and low power consumption is designed by using the chopper stabilization technique and the dynamic element matching technique. Based on the TSMC 0.18um process, the spectre environment in cadence is used for design and simulation. The power supply voltage is 1.8V. The post simulation results show that under the TT corner, the average current of the operational amplifier is 139uA, the loop gain is 85.9dB, the phase margin is 68.01°, and the power supply rejection ratio(PSRR) is 101.62dB@50Hz, the common mode rejection ration(CMRR) is 104.52dB@50Hz, the equivalent input noise is 129.86nv/sqrt(Hz)@50Hz, and the value of equivalent input offset voltage is 8.2uV(mean).
Design and stability analysis of bionic end-effector fingers for yarn tube gripping
Authors: Guan Shengqi , Wang Jingguo , Wang Xu , Yu Zijiang , Hao Zhenhu , Zhang Libo , Wang Yingyu , Wang Junqiang
Published: December 2022

According to the development demand of automatic yarn tube loading equipment in textile field, a fingertip gripping stability evaluation method is proposed and applied to the end-effector structure design suitable for multi-size yarn tube gripping. Firstly, by studying the human hand mechanism, the tendon type underdrive principle is used to design the rope sheave layout and tendon path of the end-effector finger, and its overall structural design is introduced; secondly, a virtual spring is used to establish an equivalent model of fingertip contact, and the grasping stability is evaluated from the perspective of system potential energy by constructing a stiffness matrix; on this basis, an elliptical curve under geometric constraints is used as the fingertip profile curve, and the release sample is used to Finally, quantitative analysis of gripping stability based on a yarn tube gripping model. The research results lay the foundation for the design of an efficient and reliable yarn tube gripping device. The working principle and design ideas of the bionic end-effector have some implications for the design of robotic end-effectors serving other fields.
PEMF Device With Bipolar Pulse Waves Based on Single Chip Computer
Authors: Tai Au-Zou , Fang Jiunn
Published: December 2022

PEMF therapy, a non-invasive technology, is frequently reported in medical journals. It can send electric and magnetic fields to the body through induction coils [1,2], so as to provoke cells to stimulate nerves and muscles. Based on performances of large PEMF equipment on the market, on average, the low frequency emitted by most PEMF equipment is 0-300HZ An appropriate single chip is selected to make an extremely low frequency 0-30HZ that can be easily developed and easily changed. And has bipolar pulse wave so that simple equipment can also get enough effect.
High-performances ultraviolet photodetector based on vertical van der Waals heterostructures
Authors: Liu Zhiyi , Hu Xiaomei , Long Mingsheng
Published: December 2022

High-performance ultraviolet (UV) photodetectors play a very important role in many fields, especially in the military, biomedical and other fields. [1]In recent years, many studies have realized ultraviolet photodetectors of 2D layered materials, overcome the problems of traditional ultraviolet detectors that are large and use high voltages. [1]Up to now, most of these works use atomically thin layers and simple p-n van der Waals (vdW) heterostructures, which have difficulty meeting the conditions of high sensitivity and ultrafast response at the same time. we report the double p-n van der Waals (vdW) heterostructure built on a large electrode. The two p-n junctions connected in parallel were proven to be able to effectively separate photo-generated carriers and suitable for ultraviolet light. This new type of photodetector exhibits competitive performance, including high R up to 254.8 A/W under UV light, and fast photoresponse τr = 7.9 μs and τd = 3.9 μs. These results provide an ideal platform for realizing highly sensitive UV photodetectors.
Numerical simulation and experimental comparison of antagonistic shape memory alloy linear actuator for automotive applications
Authors: Shen Chuanliang , Yue Yubing , Hu Yibo , Yu Jing
Published: December 2022

This paper introduces several commonly used constitutive models of SMA materials, expounds the relationship between material temperature, stress and strain from the perspective of one-dimensional model, and establishes the simulation model of reciprocating motion of SMA actuator based on the material parameters obtained from quasi-static mechanical property experiments in the previous paper. A double wire pull SMA actuator is designed and a prototype is made. The output displacement data obtained from the experiment is compared with the established simulation model to prove the accuracy of the simulation process.
A logic level matching circuit in a communication circuit
Authors: Yang Cheng-ying
Published: December 2022

Aiming at the problems of using optocouplers to achieve logic level matching in the current communication circuit, there are many components, high cost, and high requirements for component parameters. Based on the basic requirements of circuit logic level matching, this paper combines The research on the basic principle of triode switch, using the Schottky diode’s unidirectional conduction and low conduction voltage drop characteristics, introduces a logic level matching circuit for inter-module communication with switch isolation function in communication circuits. Through the verification of relevant experiments such as functionality, stability and reliability, the circuit has a simple structure and stable performance, and is very suitable for use in communication circuits between modules of different voltage levels.
Fatigue reliability analysis of bridge crane metal structure considering maintenance
Authors: Zhang Yanchao , Wang Hua , Li Xiangdong , Ren Qinghua , Feng Yunwen , Xue Xiaofeng
Published: December 2022

Periodic inspection and maintenance of cracks have great influence on the reliability and safety of metal structures of bridge cranes. However, the influence of maintenance factors on the fatigue reliability of in-service bridge cranes is rarely considered at present. Taking a metal structure of a certain type bridge crane as an example, this paper establishes the limit state equation according to the residual strength of the structure. Considering the reduction of section modulus by fatigue cracks, the influence of periodic inspection and maintenance is quantitatively analyzed. The fatigue reliability of metal structure of bridge crane is analyzed and calculated by using MATLAB program. The results show that the fatigue damage will lead to the continuous decrease of reliability, and the fatigue reliability of metal structure can be restored to a certain extent by considering maintenance, which delays the decrease of reliability.
Research on Optimal Control of Dual Active Full-Bridge DCDC Converters
Authors: Shi Weichao , Zhang Haiyan
Published: December 2022

The dual active full-bridge (DAB) DC-DC converter is an important module for realizing bidirectional energy transmission. At present, it has been widely used in solid-state transformers, DC microgrids, electric vehicle charging piles and other fields. It can carry out high-capacity transmission, and can electrically insulate the primary and secondary sides, and has a wide range of uses.
Research on double cylinder synchronous linear loading system based on sliding mode control with exponentially converging disturbance observer
Authors: Yan Yu , Fan Yuanxun , Qiu Haodong , Yang Zeyu
Published: December 2022

In the valve opening control of spacecraft, electro-hydraulic servo position-controlled loading is generally adopted. The nonlinear factors and uncertain interference in the loading system will affect the system accuracy. In order to improve the loading tracking accuracy and response speed, the nonlinear model of dual-channel valve-controlled symmetrical cylinder electro-hydraulic position servo loading system was established. A disturbance observer is used to estimate the unmodeled disturbances of the system, which is set up in combination with the sliding mode controller. Cross-coupling control is used to improve the synchronization accuracy of the two cylinders. The simulation study shows that the sliding mode control method based on exponentially converging disturbance observer can effectively improve the position tracking accuracy and synchronization control accuracy of the system compared with the traditional PID control. It has shorter response time and better anti-disturbance capability, which makes it have good control performance.
Research on ultrasonic cleaning power frequency tracking technology based on fuzzy adaptive PID
Authors: Gui Zhiyong , Zhao Lihong
Published: December 2022

Ultrasonic cleaning technology has been used to a certain extent in home, but the resonant frequency of the ultrasonic transducer shift with the change of temperature and external environment, eventually leading to ultrasonic transducer work in a non-resonant state, resulting in lower power output. The amplitude of the transducer decreases, which affects the cleaning effect. In view of the above problems, a frequency tracking design scheme based on the fuzzy adaptive PID is proposed, which aims automatically track the ultrasonic cleaning power supply. In this scheme, the current - phase difference composite tracking method is selected, which improves the tracking speed and accuracy under the condition of ensuring that the optimal resonance point can be tracked. The static model and dynamic characteristics of the transducer are also analyzed to derive the design of matching circuit, which enables the transducer to get the maximum power input. The feasibility and high efficiency of the design scheme are demonstrated by LT-spice and MATLAB simulation experiments, which provide a reference for the practical application of ultrasonic cleaning devices.
The Modeling and Analysis of Fuel Metering System of Gas Turbine based on AMESim
Authors: He Fengshuo , Ning Ding , Yong Lu
Published: December 2022

The fuel metering system is an essential component of gas turbine and an in-depth research on its characteristics is the basis for the design and optimization of the gas turbine fuel system. This paper presents a mathematical modeling analysis of the main components of the fuel metering system and uses AMESim to build a numerical model for computer simulation. The model is used to verify and analyze important performance indicators such as differential pressure and fuel metering response, and to propose key points for optimization in the fuel metering system.
Simulation of Brake Disc Resistance Torque of High-speed Train Considering Air Flow Field
Authors: Zhou Sufen , Zuo Jianyong
Published: December 2022

In order to study the flow field characteristics in the transfer rack area during the operation of high-speed train and the influence law on the wind resistance torque of brake disc, the train aerodynamic model is established, and the flow field of high-speed train under six working conditions of 200km-450km per hour is simulated. The calculation results show that the resistance and torque of the brake disc are directly proportional to the square of the speed, and the power consumption is directly proportional to the cubic of the speed. When the train runs at 450km / h, the maximum wind resistance torque of a single brake disc can reach 71.26Nm. The energy loss caused by the brake disc resistance torque accounts for 31.32% of the total power consumption of the bogie, which is 2.47 times of the contribution value of brake disc resistance power consumption.
Simulation and modeling of manipulator for unmanned aerial vehicles
Authors: Qin Shilong , Zhang Meng , Li Guoxi , Zhang Zhenxin , Luo Kai
Published: December 2022

In order to improve the operation ability of unmanned aerial vehicles (UAV), this paper designs a lightweight manipulator for quadrotor UAV. First, according to the requirements of the task and the load of the UAV, an aerial manipulator with lightweight and small moment of inertia is designed, and the 3D model of the manipulator is established in the Creo software. The maximum deformation and stress under different load conditions were analyzed by Ansys Workbench software, and the dynamic analysis was carried out in ADAMS software to obtain the driving moment required by each joint of the manipulator under load conditions. Finally, the dynamic model of the aerial manipulator system is established according to the Newton-Euler method, and the maximum workspace of the manipulator in the hovering state is generated by the Monte Carlo method. The research results show that the deformation and stress level are small, and the workspace meets the operation requirements, which proves that the designed manipulator has certain engineering application value.
AUV Path Planning in Dynamic Environment Based on Improved Artificial Potential Field Method Based on Visibility Graph
Authors: Xin Zhou , Rongwu Xu , guo Cheng
Published: December 2022

In order to solve the forced shaking problem of the Autonomous Underwater Vehicle (AUV) facing dynamic obstacles in the path planning when the Artificial Potential Field Method is used, a method of removing the shaking state based on a favorable path is proposed, and on this basis, Visibility Graph Method is used to optimize the path of the AUV to avoid dynamic obstacles. By judging the relative motion direction of AUV and dynamic obstacle, the moving direction of AUV is adjusted based on Visibility Graph Method when it is far away from the obstacle. When it is close to the obstacle, the direction conducive to approaching the target point is selected as the favorable forward direction to bypass the obstacle. The simulation results show that the dynamic obstacle avoidance path optimization method based on the Visibility Graph Method reduces the number of moving steps by about 19% compared with the traditional method when dealing with a single dynamic obstacle, and can be applied in complex environments with multiple dynamic obstacles.
Indoor Top Mobile Service Robot Based on Improved RRT Algorithm
Authors: Chai Yeyu , Zhao Yiting , Yin Chenyang
Published: December 2022

An indoor top mobile service robot based on the improved RRT algorithm is proposed. The robot is mainly composed of a lifting truss platform and a manipulator, which avoids the mapping and positioning of complex ground and obstacle avoidance planning. At the same time, the kinematics analysis of the manipulator is carried out. In view of the function of obstacle avoidance planning when the manipulator completes the task, the traditional RRT algorithm is improved to overcome the shortcomings of the low efficiency of path planning in the traditional RRT algorithm, and the planned path quality is uncertain and not smooth enough. The simulation environment is built based on ROS platform to verify the feasibility of the algorithm. To a certain extent, it improves the autonomy of robots to complete tasks.
Simulation analysis of a specification package for high density and high voltage power module
Authors: Cai Jiawei , Zhang Long , Huang Yingzhuo , Lin Pengrong , Yao Quanbin
Published: December 2022

A novel packaging designing for high density and high voltage power module, namely TPak was proposed. It uses flip-chip welding technology and through-hole technology to avoid the parasitic parameters introduced by wire bonding in traditional electrical interconnection, so that the proposed efficiency of the entire high-voltage module is close to 100%, parasitics are reduced by an order of magnitude, and module manufacturing is simplified and the module mechanical stress capability is improved. The finite element simulation anakysis of heat and force are carried out by means of simulation software, and the problems existing in the current Tpak packaging are analyzed from the perspective of materials, and improvement methods are proposed to optimize performance and improve its reliability.
Simulation on control system of the parallel ankle rehabilitation mechanism driven by Pneumatic Artificial Muscles
Authors: Xu Zili , Zhang Hui , Qiu Jiahui
Published: December 2022

The ankle is the most weight-bearing joint in the body, which plays a vital role in ensuring people’s walking. Aiming at the problems of complex mechanism, rigid drive and difficult control of the current ankle joint rehabilitation equipment, a 3-SPS/S type ankle parallel rehabilitation mechanism based on pneumatic artificial muscles is developed, and a self-tuning PID controller based on BP neural network is proposed to improve the accuracy of the control system. According to the static characteristics of the pneumatic artificial muscle, the physicians mathematical model of the artificial muscle is optimized, the kinematic position inverse solution of the ankle joint parallel rehabilitation mechanism is analysed and the control system is established. Combined with traditional PID control and BP neural network control algorithm, the BP_PID controller is completed, the control system is simulated and analysed. The simulation results show that BP_PID controller can meet design requirements for the ankle joint parallel rehabilitation mechanism, and is obviously superior to the PID controller in response speed and control accuracy.
Obstacle avoidance path planning of mobile robot based on improved DWA
Authors: Wang Haojie , Ma Xianghua , Zhu Li
Published: December 2022

A new dynamic window algorithm is proposed to solve the problem that the optimal trajectory is difficult to plan and the trajectory is not smooth due to the dense obstacles in the complex workshop path planning task. The algorithm sets the initial direction angle, and then improves the evaluation function through the direction angle change factor to improve the efficiency and flexibility of the algorithm; The fuzzy controller is used to adjust the coefficient of the evaluation function, which improves the adaptability of the mobile robot to the complex workshop environment. The MATLAB simulation results show that the improved DWA can plan a more reasonable and smooth running path in the area with dense obstacles, and has better obstacle avoidance effect while ensuring the safety of the robot.
Welding Numerical Simulation Analysis of AP 1000 Insert Plate and Penetration Sleeves Based on ABAQUS
Authors: Yang Xiaoyu , Guo Qi , Tang Shengming , Zhang Lijun , Chen Xiaohu , Shi Xiumei
Published: December 2022

Frequently, cracks are found in welded joints of the insert plate assembly of a nuclear reactor containment vessel. To study the residual stress state of the dissimilar steel welded joint of the insert plate assembly and ensure that there are no defects after welding, the ABAQUS finite element analysis software was used to simulate the temperature field and the post-weld residual stress field of the dissimilar steel inserted into the plate assembly in the containment of the nuclear reactor. The insert plate and sleeve material are SA738GR.B and A350, respectively; the heat treatment process after welding is simulated to predict the residual stress state of the welded joint after heat treatment. The simulation results show that the weld zone is the most sensitive to the circumferential cracks, and the maximum residual stress appears near the weld toe near the tube side.
Research on static characteristics of the metal-rubber isolator based on Abaqus software
Authors: You Jingyue , Zhao Yinglong , Zhang Ben
Published: December 2022

The rubber isolator with metal embedded inside has been developed and has been used in ships. In this paper, based on Abaqus software, static characteristics of the metal-rubber isolator under rated load are calculated by finite element method. The simple deformation experimental data processing of the rubber material, the fitting method of the hyperelastic constitutive model and the model simplification of the metal-rubber isolator are described in detail. The feasibility and effectiveness of the finite element method to analyze the static characteristics of the metal-rubber isolator is verified by experiments. The conclusions obtained in this paper can provide guidance for the rapid development of serial products of the metal-rubber isolator.
Blending ZIF-67 into PDMS membranes to promote the separation performance of propylene/nitrogen mixed gas
Authors: Lv Ming-Yu , Mao Heng , Wang Sen , Xie Wen-Wen , Shi Xin-Yu , Zhao Zhi-Ping
Published: December 2022

The membrane-based gas separation is well-suited for the recovery of hydrocarbons from nitrogen-rich exhaust gases. However, the separation performance of the existing polymeric membranes was insufficient. In this study, zeolitic imidazolate framework-67 (ZIF-67) was synthesized and then incorporated into polydimethylsiloxane (PDMS) to prepare ZIF-67/PDMS mixed matrix membranes via the spin-coating method. The resultant ZIF-67 and membranes were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscope. The C3H6/N2 (20:80 vol) mixed gas separation tests indicated that the ZIF-67/PDMS membranes achieved the higher C3H6/N2 separation factor but the lower C3H6 permeance in contrast with pure PDMS membrane. At the ZIF-67 loading of 5 wt%, the membrane displayed the optimal separation factor of 16.5 with comparable C3H6 permeance of 86.9 GPU. Besides, the relatively low operating temperature and pressure were advantageous to gaining good gas separation performance.
Fabrication of black silicon using picosecond laser irradiation assisted by Se dopant film
Authors: Du Lingyan , Yin Jie , Zeng Wei , Pang Shangzhen
Published: December 2022

Black silicon with micro-nano structures were fabricated by irradiating silicon with 1064nm laser pulses of 8.7-ps duration, 4.5 μJ per single pulse, 100mm/s scanning speed in vacuum, and doping the black silicon by irradiating the silicon coated with Si-Se bilayer film. SEM images show that the surface micron-scale grooves covered with nano-scale particles pattern was produced on Si for both the sample with no film and with Se film, but the surface structure are smoother and more uniform in the presence of Se film. EDS graph demonstrated the presence of Selenium in the black silicon micro-nano structures. Furthermore, Raman spectra results indicate that the micro-nano structured black silicon is still crystal phase.
Effect of W particle size on mechanical properties of a tungsten heavy alloy
Authors: Li Xiaolin , Li Yunkai , Zhu Yichao , Liang Yaojian , Xue Yunfei , Wang Lu
Published: December 2022

Preparing fine tungsten particles tungsten heavy alloys (WHAs) is a method to improve the susceptibility to adiabatic shear of WHAs. In this paper, W-AlCrFeNiV alloy (W-HEA) with different size W particles were prepared by laser ultrashort-time liquid phase sintering (LULPS) and liquid phase sintering (LPS). The effects of W particle size of W-HEA on mechanical property and susceptibility to adiabatic shear are studied. The results show that W-HEA with 3 μm W particles has excellent mechanical properties-tensile strength nearly 1500 MPa. The tensile strength is 58% higher than that W-HEA with 20 μm W particle. W-HEA with 3 μm W particle dynamic compression strength is 2200 MPa under 4000 s-1. The dynamic strength is 22% higher than that tungsten heavy alloy with 20 μm W particle. And the smaller W particles are, the stronger susceptibility to adiabatic shear is. The adiabatic shear band width of W-HEA with 3 μm W particles is 10 μm after dynamic compression.
Superamphiphobic coatings based on graphene oxide with abrasion resistant property by a simple method
Authors: Chen Zheyu , Niu Huiyan , Li Jiayin , Zhang Yang , Zhang Zhiyuan , Chen Haotong , Li Li
Published: December 2022

Due to the excellent physiochemical properties of graphene oxide (GO), the fabrication of superamphiphobic coatings based on GO can explore the application fields of GO. Herein, superamphiphobic GO coatings are fabricated by simple dip coating GO and organosilane polymer (GO-FAS) dispersion on the cotton fabric, with GO acting as solid lubricant originating from its low friction coefficient. Through compound with PS/PTFE and PVDF-HFP/FAS, the PVDF-HFP/FAS/GO-FAS coating exhibit enhanced anti-abrasion property and can withstand 200 cycles of sandpaper abrasion. This study provides an opportunity for the applications of graphene oxide as superamphiphobic materials.
A metastable lightweight high entropy alloy with the transformation induced plasticity
Authors: Han Mengyunqing , Wang Liang , Wang Lu , Xue Yunfei , Wang Benpeng
Published: December 2022

Body-centered cubic (BCC) high entropy alloys (HEAs) usually have poor ductility, limiting their engineering application. Here we present a TiZrNbAl non-equal atomic-ratio HEA (Z25) which shows martensitic transformation during tensile deformation. This transformation effectively improved the uniform ductility to around 17%. The gradually induced martensite lamella shows the “dynamic Hall-Petch” effect during transformation, which reduces the mean free path of dislocation slip, resulting in Z25 alloy with excellent ductility and remarkable work hardening effect.
Modeling analysis of a novel hybrid 6-DOF vibration isolation platform for sensitive instruments
Authors: Zhang Yang , Fu Weiwei , Wang Lijun
Published: December 2022

The inevitable vibration caused by normal operation of the spacecraft in orbit will interfere sensitive instruments, such as space telescope, reconnaissance camera, space interferometer. Serious vibrations affect the accuracy and reliability of the sensitive instruments, even cause flight mission failed. This paper presents a hybrid 6-DOF vibration isolation platform (HVIP) with six degree-of-freedom for active vibration isolation of the space sensitive instruments. The HVIP is composed of three orthogonal vibration isolation module, which composed of the active piezoelectric actuator and passive rubber isolator. The dynamic model of the HVIP is established based Lagrange equation approach. Finally, the numerical simulations are performed to verify the vibration isolation effect of the HVIP.
Influence of brake chamber pressure and effective cross-sectional area on time delay of pneumatic braking system
Authors: Xu Shuquan , Wu Guofang , Liu Fujia , Yang Xiaojuan
Published: December 2022

To face the problem of freight safety and reduce the traffic accidents, the influence of the response time of the pneumatic braking system on the braking performance should be investigated, which can improve the safety level of vehicle. The mathematical model of the pneumatic braking response time was established in this paper. The parameters of the pneumatic braking time and the time delay characteristics of the pneumatic braking system was discussed. The results show that the pressure and effective cross-sectional area of the brake chamber are the main factors affecting the time delay of the pneumatic braking system. When the effective cross-sectional area of the brake chamber is certain, the push rod stroke of the brake chamber increases significantly with the increase of air pressure; when the brake chamber pressure is constant, the larger the effective cross-sectional area of the brake chamber, the greater the output thrust of the brake chamber push rod.
Research and Realization of Servo Control System Based on Medical Centrifuge
Authors: Shi Jite , Gu Huihui , Shi Chuandao
Published: December 2022

The power of the medical centrifuge is provided by the permanent magnet synchronous motor, so the AC control system of the permanent magnet synchronous motor directly determines the overall performance of the centrifuge. In this paper, the permanent magnet synchronous motor is the controlled object, the DSP28335 is used as the main control chip, and combined with the vector control strategy, the permanent magnet synchronous motor AC servo control system is designed. Finally, according to the design scheme, the soft and hard design of the motor control system is completed, and the system test is carried out. The test results show that the designed servo control system has fast response, good tracking performance, and stable operation, and has a certain market application prospect.
Simulation analysis of rolling bearings based on explicit dynamics
Authors: Zeng Fan , Liu Yong-bao , Wang Qiang , Li Jun
Published: December 2022

Based on LS-PrePost software, the three-dimensional display of healthy cylindrical roller bearings was established finite element model for dynamic simulation. Based on the explicit algorithm, the model analyzes the law of bearing stress level with radial outward load under the conditions of friction contact, speed and load, and based on the healthy roller bearing model, simulates the local spalling fault of the outer raceway by setting the unit defect, and analyzes the equivalent force change process when the roller through the fault area. The simulation results are compared with the theoretical calculation results to verify the correctness of the finite element model of the faulty bearings, and provide a certain reference for the fault diagnosis of rolling bearings.
Simulation and Optimization of Penalty Kicks and Shooting Probability Based on Monte Carlo Method
Authors: Jiao Tiankuo
Published: December 2022

Since there are few models that specialize Penalty kicks probability or shooting accuracy, this research innovatively uses the Monte Carlo method to simulate the situation of real football penalty kicks and shooting. Unifrom random generator and normal random generator are both used to better simulate the real situation, and finally the most suitable distribution model is chosen from these two distributions. Since the existence of goalkeepers is considered in a real football competition, this simulation experiment also divides the goalkeeper’s actions into 5 types, and the corresponding probability of each action is also considered. Finally, specific shooting probability is collected from the Premier League in 2021 to compare with our simulated situation to obtain the most accuracy model. By comparing with real probability, I finally confirm the appropriate model and the goalkeeper’s action probability. Similarly, the Monte Carlo method can also simulate some other real situations to determine the most suitable model.
Optimal Control of Microgrid Integrated with PV, WT and BESS
Authors: Sun Huaiyu
Published: December 2022

Distributed renewable sources (DES) are widely deployed to satisfy the requirements of increasing energy demand, slowing down the consumption traditional energy and reducing the side effect on environment. However, with the increasing amount of DES connected into the microgrid, the stability, robustness and economy of grid will encounter with some challenges. So, this paper will discuss the energy management system (EMS) of microgrid integrated with wind turbine (WT) system, photovoltaics (PV) system and battery energy storage systems (BESS) to realize the stability, enhance the robustness and reduce the cost of microgrid. This paper first reviews the current relative works. Secondly, the mathematical model of microgrid is constructed which is followed by the different microgrid control strategies. Then, the simulation with results is provided.
The Overview of Elliptic Curve Cryptography (ECC)
Authors: Yan Yuhan
Published: December 2022

Elliptic Curve Cryptography (ECC) is one of the strongest and most efficient cryptographic techniques in modern cryptography. This paper gives the following introduction: The introduction of cryptography’s development; the introduction of the elliptic curve; the principle of ECC; the horizontal comparison between ECC and other types of cryptography; the modern breakthrough of ECC; the applications of ECC; by using a method of literature review. The study’s findings indicate that this factor is responsible for the rapid historical development of cryptography, from the classical password to the leap to modern cryptography. Elliptic Curve Cryptography (ECC), as one of the most important modern cryptographies, is stronger than most other cryptographies both in terms of security and strength, because it uses an elliptic curve to construct and, at the same time, uses mathematical operations to encrypt and generate keys. At the same time, elliptic curve cryptography can continue to improve the speed and intensity with the improvement of accelerators, scalar multiplication, and the speed of order operation. The applications of the elliptic curve in ECDSA and SM2 are very efficient, which further illustrates the importance of elliptic curve cryptography.
Mission Planning in Time-Invariant Domains with MDPs and Gaussian Distribution
Authors: Yuan Minsen , Shi Zhenshan , Shen Zhouyi
Published: December 2022

This thesis uses the Markov decision process (MDP) to investigate how the optimal path is decided by the underwater robot in the presence of different currents. The use of this MDP decision allows the machine to reduce the unwanted travel energy and travel time in different environments, enhancing the cost of using the machine. The scope of the study is a specific problem, and the paper describes how to use a python planning framework to solve path selection in the case where the direction and strength of the currents are determined, while incorporating a probability distribution of Gaussian functions in a finite space. The dynamical ocean current problem is used as a basis to use the MDP decision process. The final results show that the present study meets the hypotheses presented in the expectations. The results are able to simulate that the robot can find the optimal path and reach the target point when facing different currents underwater. By expanding the spatial extent of the observation and changing the parameter settings, it is possible to simulate the robot’s path in other situations. The research method can be extended from specificity to generality, and the same research method can be used to obtain optimal path decisions for other different situations.
Group Theory and Ring Theory
Authors: Xue Zeqi
Published: December 2022

Group theory is an important theory in abstract algebra. A ring is a kind of algebraic system with two operations (addition and multiplication). It has a deep relationship with groups, especially with the Abelian group. In this essay, the ring and the residual class ring will be talked about. Firstly, this passage is aim to talk about some basic knowledge about the ring which will let readers have a basic understanding of a ring. Then this passage will discuss the residual class ring and subring of the residual class ring of modulo. Some concepts about the ring are also mentioned, such as the centre of the ring, the identity of the ring, the classification of a ring, the residual class ring, the field and the zero divisors. The definitions of mathematical terms mentioned before are stated, as well as some examples of the part of those terms are given. In this passage, there are also some lemmas which are the properties of ring and subring. Future studies of rings and subrings can focus on the application of physics.
Overview of Research Progress of Digital Image Processing Technology
Authors: Huang Yitao
Published: December 2022

Digital image processing technology has gone through rapid development and is extensively applied in daily life and production, with the rapid development of modern information technology. It plays an inestimable role in remote sensing, medicine, recognition and other fields. This paper briefly introduces the basic concept of digital image processing, summarizes and analyses the commonly used digital image processing technology and the latest scientific research achievements from four aspects, and puts forward the future development direction of digital image processing. In the future, it will pay more attention to artificial intelligence algorithms and achieve better processing results by optimizing the logical structure. By using the simplified image algorithm, the application scope of digital image processing will gradually expand, and will develop in the direction of miniaturization, intelligence, and convenience.
Literature Review on Image Restoration
Authors: Liu Zihan
Published: December 2022

Image restoration is an essential part in the field of computer vision, which aims at predicting and filling the pixels of the missing images to achieve satisfactory visual effects, it has extensive application value in the fields of film and television special effects production, image editing, digital cultural heritage protection and virtual reality. With the introduction and application of the concept of deep learning in recent years, it has been widely studied in the academic and industrial fields, the performance of image restoration has been significantly improved, so that this long-standing research topic has once again aroused widespread concern and heated discussion on the social level. In order to enable more researchers to explore the theory of image restoration and its development, this paper reviews the related technologies in this field: firstly, the traditional image restoration methods are described, secondly, the background of deep learning is introduced, then the image restoration methods based on deep learning are described, subsequently, the several deep-learning based methods are compared and analyzed, finally, the future research direction and emphasis of image restoration are analyzed and prospected.