bluuebunny/crossref_metadata_2025 huggingface dataset:
Predictive Set Point Modulation Control for Lithium-ion battery Management Systems with DC-DC Converters
Authors: Yan Jiahao , Meng Qianqian , He Yuanhao , Chen Ze
Published: July 2024

Lithium-ion batteries, widely used in devices such as smartphones, remote controllers, and electric vehicles, often require adjustments to the output voltage to meet the varying demands of different devices. For instance, smartphones dynamically change the battery supply to enhance battery life, and electric vehicles necessitate different load voltages due to frequent start-stop cycles. This introduces the need for DC-DC converters to step up or step down the load voltage. However, this poses challenges to the stability of the bus voltage. In this study, we adopt a method for regulating the bus voltage reference value to predict and stabilize the voltage supplied by lithium-ion batteries. We first model the power supply system of lithium-ion batteries and then design a cascaded control framework for the voltage of DC bus. We introduce a predictive set-point control approach that eliminates the necessity to modify the energy storage system to mitigate voltage fluctuations. Simulation results illustrate that the proposed method effectively mitigates voltage overshoots in the DC bus.
Analysis of Parasitic Parameters and Winding Loss Characteristics of High-Frequency Transformer under Different Winding Structures
Authors: Dou Minglei , Zhao Wenliang , Zhang Li , Sun Youliang
Published: July 2024

With the development of the smart grid and the increasing access of renewable energy to the distribution grid, the traditional AC power grid puts forward an urgent demand for power electronic transformer (PET). The high-frequency transformer (HFT) serves as the core equipment of PET, and its electromagnetic structure and parasitic parameters are the hot spot of study in the field of power electronics. In this paper, the parasitic parameters, winding loss, and leakage magnetic field characteristics of the 20 kHz, 20 kVA HFT are investigated under different winding structures. The results show that the higher the degree of crossover of HFT winding, the lower the leakage magnetic field. The cross winding reduces winding loss and leakage inductance, and also attenuates the impact of frequency variations. The higher the winding height, the lower the leakage inductance. As the insulation thickness increases, the leakage inductance rises. The distribution capacitance varies opposite to the leakage inductance. Based on the analysis of winding loss and parasitic parameters, as well as the consideration of insulation, the final winding layout, the height of winding and the thickness of insulation of the HFT are determined.
Optimization Scheduling Strategy for Energy Storage and Cement Load Aggregation Considering Production Constraints
Authors: Xiao Kang , He Zichen , Xiao Yuduo , Chang Delong , Zhang Pengchao
Published: July 2024

For energy-intensive cement enterprises closely related to adjustable potential and production processes, an optimization scheduling model is proposed based on the coupling relationship between tasks and materials, taking into account the production constraints of cement users. In addition, energy storage-side pumped storage is aggregated to regulate resources, further enhancing the flexibility of regulation. For pumped storage devices, the constraints include power constraints during the charging and discharging process, power equality constraints, state constraints during charging and discharging, energy state constraints, and final energy constraints. For cement enterprises, taking the example of the new dry cement production process, the generation/consumption of materials and the occupation/release of equipment in each process are analyzed. The state-task network method is used to abstract materials and processes into states and tasks respectively, establishing process constraints for cement load production. Case simulation verifies that the proposed method can effectively reduce the comprehensive electricity cost of pumped storage and cement enterprises while ensuring the normal operation of pumped storage and cement enterprises, providing data guidance and support for cement enterprises to participate in grid interaction.
Research on Anti-breakage Target Detection Method of Transmission Line based on Improved YOLOv5
Authors: Chen Wentao , Ding Yang , Lin Menghao , Song Hui , Li Tong , Gong Songbai
Published: July 2024

Illegal construction operations and sudden outbursts in transmission corridor protection areas pose a threat to the safe and stable operation of transmission lines. It is very important to identify the transmission line breakage risk to guarantee power grid security. The existing target detection model has many parameters and a large capacity, which makes it difficult to implement the deployment of edge terminals and cannot detect the risk of transmission line outbreaks in real time. This paper proposed a transmission line anti-breach detection method based on improved YOLOv5. Firstly, the CSPdarknet53 module is replaced with a lightweight MobilenetV3 module to reduce the model parameter number. The SPP module is replaced by SimSPPF module to realize the fast conversion of multi-scale image convolution features. Finally, the ECA attention mechanism is introduced to improve the ability of the model to focus on key features, thereby improving the overall performance of the model. Experiment results show that the proposed method has a smaller parameter number and a mAP value of 97.77%, which is the best overall performance, and provides support for the realization of outbreak risk warning of transmission lines based on edge intelligence.
An Equivalent PCS Model for Energy Storage System
Authors: Ma Dajun , Zhang Xing , Li Xu , Ding Yong , Li Gang , Lu Yu
Published: July 2024

The power conversion system (PCS) for energy storage system (ESS) has been rapidly developed in recent years, due to the more and more integration of new energy sources. Before the large-scale applications of PCSs in practice, the simulation works are essential to verify its performances. The conventional switching PCS model has been reliably used to complete simulation work, when the number of PCS is less. Nevertheless, when the simulation work with large-scale PCSs is carried out, the number of PCS will be enormous, the simulation work will be difficult to be completed by the switching PCS model, because of the unacceptable long simulation time. Hence, an equivalent PCS model is needed and proposed in this paper. The topology and control mothed of the equivalent PCS model are concretely introduced. The simulation works with steady state and dynamic process are completed by both switching PCS model and the proposed equivalent PCS model. The compared results illustrate the high accuracy of proposed equivalent PCS model. The real simulation times for two models are calculated and compared, which illustrates the high rapidity of proposed equivalent PCS model.
Multi-Objective Optimization Scheduling of Microgrids Considering Single Use Cost of Energy Storage and Unit Combination Startup and Shutdown Cost
Authors: Zhang Baojie , Sun Yiqian , Zhao Hongfeng , Hao Hongyan , Kang Pengpeng , Yang Guixing , Liu Defu , Fan Guowei , Liu Guowei
Published: July 2024

Microgrids typically consist of various energy resources such as thermal power, solar energy, wind energy, energy storage, and so on. These energy resources have different characteristics and fluctuations. By utilizing the characteristics of different energy resources in a complementary and synergistic manner, their energy utilization efficiency can be promoted and the system stability can be improved. This paper considers the energy storage device in the completion of a single charge and discharge loss, that is, the single-use cost. Special attention to the impact of start-stop costs of unit combinations on microgrid operations. It proposes that in the daily dispatch and operation of microgrids, sinking costs can be reasonably reduced within a reasonable range, and power supply reliability can be appropriately lowered to improve the economic performance of power systems. Using the single-use cost of energy storage devices and the start-stop costs of unit combinations as variables, their impact on the economic operation of isolated microgrids is analyzed. For grid-connected microgrids with the objectives of minimizing operating costs and achieving optimal environmental protection, an optimal balance between economic and environmental performance is achieved through solving by Anti-Entropy weight method and Particle Swarm Optimization combination.
Analysis on Discharge Fault of Busbar in 220kV Gas Insulated Switchgear
Authors: Wang Yi , Bi Conglai , Qi Zhuang , Gao Qian , Sun Zhe , Bai Xuelei
Published: July 2024

In this paper, the disintegration of the 220kV gas insulated switchgear (GIS) basin-type insulator which discharge is occurred during the restoring power supply process of a 220kV transformer substation is introduced. The relay protection action is analyzed and the results of predelivery test are traced. Meanwhile, the electric field of the basin-type insulator is simulated and analyzed. Finally, the cause of discharge fault of basin-type insulator is determined.
Architecture Research on Differentiated Lightning Protection of Distribution Network Considering Plateau Microtopography
Authors: Hu Chunhua , Dong Tiezhu , Chen Xin
Published: July 2024

Lightning is the main and severe threat to 10kV and 35kV medium-voltage distribution networks. It will cause equipment failures or damage, tripping and even power outages. With the construction of modern distribution networks, the requirements for power supply reliability are getting higher and higher. Therefore, lightning protection of distribution networks has received great attention. The key point is to find a cost-effective way to protect against lightning. This paper proposed an architecture for differentiated lightning protection of distribution networks considering plateau micro-topography. The main idea is to take multiple measures to obtain rich data, including a lightning positioning system, 3D laser scanning and digital elevation model. Differences in lightning parameters, line and tower parameters, topographic parameters are thought to bring different lightning tripping rates for each tower. Then tripping rate of each area element is obtained through meshing and discrete calculation. Total tripping rate is finally obtained by summation of all elements. The proposed architecture plans to provide a clue for differentiated lightning protection for the distribution network.
Research on Probabilistic Load Modeling and Simulation Model of Electric Vehicle Charging Station
Authors: Pan Yan , Zhang Peiwen , Zhao Wei , Xu Peng , Chen Qifang , Dong Ye
Published: July 2024

The stochastic nature of electric vehicle charging station loads poses certain challenges in establishing relevant load models. This paper introduces a probabilistic load modeling approach that considers factors such as the time electric vehicles begin charging, daily travel distance, charging power, and charging duration. By comprehensively studying the influencing factors of charging station load modeling and combining Monte Carlo simulation with probabilistic statistical analysis, a comprehensive probability load model for typical charging stations is developed. Building upon this, a charging load simulation model is constructed using Simulink. This model can generate daily load curves consistent with the probability load model, making a positive contribution to the study of the impact of electric vehicles on the power grid.
Review on Risk Assessment of Power System under Rainstorm-Flood and Disaster Control Improvement Strategies
Authors: Wu Wenjie , Hou Hui , Zhou Yangjun , Wei Guohui , Zhang Wei , Zhong Shiwen
Published: July 2024

The global warming and El Nino effects are becoming more and more obvious now. These result in frequent rainstorms, especially in coastal areas. It is necessary to deeply study evolution mechanism of rainstorm-flood disasters, assess disaster risk of power grid, and formulate efficient power grid flood control strategies. Firstly, the research progress of disaster modeling is summarized according to the disaster evolution mechanism. The differences between hydrological models and machine learning models are compared, and the possibility of combining them is discussed. Secondly, current disaster risk assessment methods of power grid and their application in rainstorm-flood disasters to quantify flood prevention capacity are reviewed. Thirdly, the power grid flood control measures are studied from the perspective of pre-disaster grid reinforcement and post-disaster repair to improve resilience. Finally, in view of the above content, the shortcomings of current researches and feasible research directions in the future are proposed.
Integrated Structural Hole and K-shell Algorithm for Tsallis Entropy-based Identification of Key Nodes in Power Grids
Authors: Wei Qian , Song Wenrong , Ji Li , Zhang Yiwei , Sun Yongguang , Sun Hongjun
Published: July 2024

Considering the low-carbon development goals of “peak carbon emissions and carbon neutrality,” traditional energy enterprises, including oil fields, have accelerated the incorporation of new energy into their power grids. However, incorporating new energy generation into traditional oilfield power grids yields a series of safety hazards, making the stability of the oilfield power grid structure increasingly important. In this paper, a redefined theory of structural holes and the K-shell algorithm are utilized to identify both local and global key nodes in the oilfield power grid. The improved Tsallis entropy is employed to recognize these key nodes, accounting for their local influence within the oilfield power grid as well as their global status. Additionally, considering the electrical characteristics of the nodes, a set of measurement metrics suitable for oilfield power grid research is constructed. Finally, the IEEE-39 feeder system is simulated and compared with other key node identification methods. By analyzing the robustness of the topological structure and the loss load value of the power system after removing key nodes, the reliability and superiority of the proposed method are verified.
Research on Partial Discharge Characteristics of Suspension Defect in GIS under the Action of Voltage and Current
Authors: Bao Zhenghong , Ren Jiyun , Wang Lili , Wang Shengjie , Chen Yao , Li Zibin , Wang Zile , Ma Yongfu , Li Liao , Chen Huan
Published: July 2024

Gas insulated switchgear (GIS) is a critical component in power system, and the insulation testing is crucial before putting it into operation. Despite passing AC withstand tests, some GIS equipment exhibit insulation faults during operation. Existing AC withstand tests fall short in detecting all insulation faults in GIS equipment. To address this issue, a proposal is made to conduct a comprehensive simulation of actual GIS equipment operating conditions through a combined voltage and current boost test, aiming to address the limitations of existing tests. This study, based on a 330kV GIS test platform, compares the partial discharge characteristics of suspension defects under traditional voltage-boosting mode and the combined voltage and current boost mode. The research investigates the influence of simultaneously applying voltage and current on discharge characteristics. It is observed that the voltage and current boost combined mode significantly increase the partial discharge inception voltage (PDIV) and the corresponding apparent discharge compared to other modes. The apparent discharge quantity after a certain period of current flow during the discharge development process is greater than that observed in other modes. The current notably enhances the ultrasonic amplitude of partial discharge. These findings establish an experimental foundation for conducting voltage and current combined boost tests in the field.
Low-voltage Compensation of Distribution Networks Based on A Hybrid UPQC with Single and Three-phase Converters
Authors: Chen Shichuan , Shen Xielin , Yuan Bo , Peng Weiwen , Ye Hua , Lei Zhiping
Published: July 2024

For remote distribution networks, low voltage is prevalent, which seriously affects the normal use of electricity. Aiming at solving the voltage sag/dip problems in 10.5 kV distribution networks, a hybrid UPQC with a shunt single-phase rectifier and a series three-phase inverter is proposed in this paper. The shunt single-phase rectifier is connected to the feeder lines with the highest and lowest voltage phases to supply enough energy to the series inverter, and the three-phase inverter compensates the voltage deviation by injecting active power through a series transformer, such that the voltage sag/dip problems can be mitigated. The control strategies of the two converters are designed in detail in this paper. Compared with the traditional UPQC with two three-phase converters, the proposed method has the advantage of simpler control methods and lower cost. Finally, the proposed method is verified through MATLAB/Simulink model.
Analysis of the dynamic characteristics of air-breathing supersonic missiles considering the effects of elasticity and actuator faults
Authors: Wei Zhihua , Ming Chao , Yang Kaiyuan , Yan Suyu
Published: July 2024

The air-breathing supersonic missile has the characteristics of strong nonlinearity, strong coupling, fast time degeneration, and strong uncertainty. With the increasing requirements for missile speed and accuracy, the elasticity and actuator fault of air-breathing supersonic missiles have become a problem that cannot be ignored. In this paper, the longitudinal dynamics model of the elastic air-breathing supersonic missile is established, the influence of the elasticity of the air-breathing supersonic missile on the attitude is analyzed considering the real-time change of fuel mass, and finally, the comprehensive influence of the elasticity of the air-breathing supersonic missile and the actuator failure on the dynamic characteristics of the missile is analyzed, and the research results can provide reference for related research in this field.
Gap distance of UHV substation in areas with an altitude of 5000 m and below
Authors: Yao Xiuyuan , Su Yu , Zhou Songsong , Ding Yujian , Lin Yifan , Jiang Ling , Xie Shijun
Published: July 2024

In view of the increasing energy consumption and power demand, the construction of UHV AC is growing rapidly, and the construction of the project is gradually advancing to higher altitudes. It is urgent to conduct research on typical gap discharge in substations at high altitudes. Combined with the engineering requirements, this paper corrects the test data at an altitude of 0 m according to GB/T 24842 standard through altitude correction and combines the discharge voltage requirements of various typical gaps in substations to obtain the minimum air gap distance in UHV substations at an altitude of 5000 m and below. The calculation results of the two altitude correction methods are compared and analyzed, and the applicability of the two methods is analyzed.
Research on electromagnetism scattered from electricity power supply towers based on orthogonal test designs
Authors: Zong Shiqi , Jiao Chaoqun , Zhang Jiangong , Gan Zheyuan
Published: July 2024

For the protection of transmission towers against electromagnetism interference to peripheral radio radar stations, this paper designs orthogonal tests to investigate the electromagnetism scattered efficiency of UHV transmission towers. The towers were mathematically modeled, and the influence of three main factors, tower spacing, frequency, and number of transmitting pylons, on the electromagnetism scattered is investigated. Each factor corresponds to three levels of study and nine sets of orthogonal tests were designed to greatly simplify the number of simulations. Three-factor analysis of variance was undertaken on test data and demonstrated that frequency was the main factor affecting electromagnetic scattering, with tower spacing being the next most influential and many towers the least influential. With the main and secondary effects in mind, the combination with the most significant effect of interaction effects on electromagnetic scattering was selected as the five towers with frequency 1400 kHz and tower spacing 200 m. The investigated outcomes lay the foundation and supply instructions for multi-factor analyses of electromagnetic scattering.
Optimal design of electromagnetic repulsion mechanism based on hybrid infill criterion and kriging surrogate model
Authors: Xie Haixin , Miao Xiren
Published: July 2024

In the optimization design of the electromagnetic repulsion mechanism in finite element simulation, there are problems of high computational cost and long optimization time. To shorten the development cycle of the prototype and improve the efficiency of optimization, an optimization algorithm based on the Hybrid Infill Criterion and Kriging Surrogate Model (HIC-KSM) is proposed by organically combining the Expected Improvement (EI) infill criterion and the Pareto front infill criterion to make full use of the performance of parallel computation and to accelerate the convergence speed of the algorithm. The proposed algorithm is compared with the other optimization algorithms, the optimization results of five multi-objective test functions are compared to verify the efficiency of the proposed algorithm, and the algorithm is applied to the parameter optimization of the electromagnetic repulsion mechanism.
Learning predictive control of wheeled mobile robot with communication delays
Authors: Wu Ruizhuo , Xu Xin , He Ming , Liu Daxue , Zhang Xinglong
Published: July 2024

This paper proposed a learning predictive control method for wheeled mobile robots with communication delays. In consideration of the property in the Networked Control System (NCS), communication delay was divided into two types: delay from sensor to controller and delay from controller to actuator. For each type of delay, state prediction and state augmentation techniques were utilized respectively to diminish their passive impact on the control of WMR. Then receding horizon reinforcement learning approach was adopted to learn the optimal policy based on the delay compensation. Finally, simulations were performed applying the proposed method to the trajectory tracking of WMR and showed the validity of the proposed scheme.
Design of a textile storage environment fire detection system based on ZigBee and NB-IoT
Authors: Lin Jun , Xu Xiaobin
Published: July 2024

A fire monitoring and early warning system based on Zigbee and NB-IoT (Narrow Band Internet of Things) has been designed for fire prevention in textile storage environments. The NB-IoT architecture is used for fire monitoring and early warning system systems. Zigbee terminal equipment is used as a node to collect environmental data and process data through the fog sensor MQ-5. The data is uploaded to cloud servers through NB-IoT technology to achieve remote fire monitoring and early warning. The experimental results show that the detection system can obtain real-time and accurate information in the storage environment. The detection system can achieve monitoring and early warning functions. In order to improve security, the warehouse is set up with five different detection positions. The detection system can, to some extent, reduce the probability of fire occurrence.
Integral global fast terminal sliding mode control for LLC converters
Authors: Lu Jinzhi
Published: July 2024

The complex characteristics of full-bridge LLC converters and PFM mode of operation result in a variety of operating modes and characteristic changes at different operating frequencies, thus increasing the difficulties in small signal characteristic analysis and good compensator design. In terms of control strategy, the traditional linear controller has limited response performance under various operating conditions such as input voltage ripple perturbation, input voltage mutation, and load mutation. To obtain greater transient response performance, stronger disturbance capability, and higher input stability of the system under different operating conditions, this paper proposes a new integral global sliding mode control law for LLC converters. In contrast to conventional control methods, the proposed control strategy exhibits enhanced dynamic response capabilities in the presence of load variations. It effectively mitigates jitter issues during steady-state operation, demonstrating a superior control performance.
Directional motion behavior of metallic conductive particles in GIS
Authors: You Yi , Yang Zhushi , Zhao Puzhi , He Cheng
Published: July 2024

Currently, metallic conductive particles constitute a significant risk to GIS insulation, and the motion of the particle is the direct cause of GIS insulation failure. The motion characteristic of particles is the key to conducting the study about the mechanism of particle-induced GIS insulation failure and the technology of particle suppression. However, current research lacks an analysis of the axial motion of particles, which should not be ignored. In this paper, the intensity and direction of the axial Coulomb force in the vicinity of the basin insulator are analyzed. Based on this, the relationship between the polarity of the charge on particles and the axial Coulomb force with time under AC voltage is analyzed. The research results show that the axial Coulomb forces on the outwardly and inwardly curved surfaces of the basin insulator have opposite directions so that they can propel the particles in the direction of the outwardly curved surface. Finally, the verification experiment conducted on the 252 kV GIS can also prove that particles indeed have the trend of directional motion under AC voltage, and multiple particles will eventually gather on the outwardly curved surface side. The research provides theoretical support for the motion of metallic particles and the particle suppression technology in GIS.
Coordinated control system of driving equipment
Authors: Cheng Fengxia
Published: July 2024

This paper introduces the composition of complete sets of driving equipment, including driving equipment, anchoring and breaking equipment, transportation equipment, and the control principle of the linkage of driving equipment, anchoring and breaking equipment, and transportation equipment, puts forward the hardware system composition of each sub-equipment, and redundant design has been carried out for communication between devices, with wired as the main and wireless as the auxiliary. The application shows that based on the dual communication network, the collaborative linkage control of the complete set of mining equipment has achieved good results, achieving coordinated control of equipment walking, starting and stopping, and improving the excavation speed of the tunnel. Its successful application has accumulated valuable experience for achieving unmanned control of excavation face equipment.
Research on prediction model of quantitative relationship of pressure attenuation of hydrogen fuel cell air compressor based on artificial neural network
Authors: Liu Qi , Han Yubo , Liu Zhen , Yuan Shuo , Liu Jianxiong
Published: July 2024

This thesis considers the field of the pressure attenuation of hydrogen fuel cell air compressors as the main subject of its study. Traditional methods usually model the prediction of pressure attenuation based on a durability test or physical model, which is costly and time-consuming. Based on the method of artificial neural network (ANN), this paper establishes a prediction model of the quantitative relationship of outlet pressure attenuation of hydrogen fuel cell air compressors. A neural network is used to capture the nonlinear relationship of outlet pressure of air compressors, and the prediction results of the model are analyzed and explained to explore the attenuation process of outlet pressure of hydrogen fuel cell air compressors. The comparison between the actual test data and the predicted data through the endurance test of the air compressor shows that the prediction ability of the model is good, and the correlation of the regression analysis results of the prediction model is above 0.99, which can be used to predict the quantitative relationship of outlet pressure attenuation of hydrogen fuel cell air compressor.
Intelligent analysis method of power grid monitoring signals based on affinity propagation clustering
Authors: Pei Zhen , Gao Xuebing
Published: July 2024

As the scale of the power grid continues to expand, power supply companies centralize the management of grid monitoring signals at substations to adapt to the actual development of the power grid and improve the performance of grid operation. However, this leads to problems such as too many invalid signals, unidentified signal classification, excessive signal volume, and too many interfering signals at the monitoring site on a daily basis, which leads to difficulties in monitoring and certain security risks. Addressing this problem, this paper introduces a method of spatialization of text data using unique thermal coding and intelligent analysis of monitoring signals using AP clustering. The affinity propagation clustering algorithm can classify the monitoring signals faster and more accurately, count the number of signals, and deeply excavate the intelligent information implied therein. This greatly enhances the stability and safety of power grid operation. The proposed method is validated by the actual monitoring signal data.
Modelling remote barrier detection to achieve free-flowing river targets
Authors: Parks Millicent V , Garcia de Leaniz Carlos , Jones Peter E , Jones Josh
Published: July 2024

Fragmentation caused by artificial barriers is one of the main stressors of rivers worldwide. However, many barrier inventories only record large barriers, which underestimates barrier numbers, and hence fragmentation. Corrected barrier numbers can be obtained via river walkovers, but these are costly and time consuming. We assessed the performance of remote sensing as an alternative to river walkovers for barrier discovery by comparing the number and location of barriers detected in the field with those detected using Google Earth imagery. Only 56% of known barriers could be detected remotely, but machine learning models predicted the likelihood of remote detection with 62%–65% accuracy. Barriers located downstream were twice as likely to be detected remotely than those in the headwaters, the probability of detection diminishing by 3%–4% for every decrease in Strahler stream order and for every 10 km increase in distance from the river mouth. Barriers located in forested reaches were 35% less likely to be detected than those in open reaches. Observer skills also affected the ability to locate barriers remotely and detection rate varied by 11% between experienced and less experienced observers, suggesting that training might improve barrier detection. Our findings have implications for estimates of river fragmentation because they show that the most under-represented structures in barrier inventories, i.e. small barriers located in forested headwaters, are unlikely to be detected remotely. Although remote sensing cannot fully replace ‘boots on the ground’ field surveys for filling barrier data gaps, it can reduce the field work necessary to improve barrier inventories and help inform optimal strategies for barrier removal under data-poor scenarios.
Green finance and grey air: Assessing the impact of green finance pilot zones on company-level pollution in China
Authors: Luo Chen , Lyu Huaiqian , Wen Tianzuo , Qiang Will W , Lee Harry F
Published: July 2024

In 2017, China introduced the Pilot Zones for Green Finance Reform and Innovations to achieve sustainable and high-quality economic growth. While this policy aims to promote the green transition of businesses and has drawn significant attention, its micro-operational mechanism and firm-level impact remain largely unexplored. This study addresses this research gap by employing a quasi-experimental approach to examine the policy’s effects on companies. The empirical results of our research highlight an unexpected 5.54% surge in the PM2.5 concentration levels in the vicinity of these firms. Given these findings, we call on policymakers to reflect on the environmental consequences following the roll-out of the Green Finance Reform. Simultaneously, we stress the significance of corporate responsibility in disclosing pertinent indicators and environmental data.
Volatile organic compounds in exhaled breath: a promising approach for accurate differentiation of lung adenocarcinoma and squamous cell carcinoma
Authors: Li Xian , Shi Lin , Long Yijing , Wang Chunyan , Qian Cheng , Li Wenwen , Tian Yonghui , Duan Yixiang
Published: July 2024

Lung cancer subtyping, particularly differentiating adenocarcinoma (ADC) from squamous cell carcinoma (SCC), is paramount for clinicians to develop effective treatment strategies. In this study, we aimed: (i) to discover volatile organic compound (VOC) biomarkers for precise diagnosis of ADC and SCC, (ii) to investigated the impact of risk factors on ADC and SCC prediction, and (iii) to explore the metabolic pathways of VOC biomarkers. Exhaled breath samples from patients with ADC (n = 149) and SCC (n = 94) were analyzed by gas chromatography-mass spectrometry. Both multivariate and univariate statistical analysis method were employed to identify VOC biomarkers. Support vector machine (SVM) prediction models were developed and validated based on these VOC biomarkers. The impact of risk factors on ADC and SCC prediction was investigated. A panel of 13 VOCs was found to differ significantly between ADC and SCC. Utilizing the SVM algorithm, the VOC biomarkers achieved a specificity of 90.48%, a sensitivity of 83.50%, and an area under the curve (AUC) value of 0.958 on the training set. On the validation set, these VOC biomarkers attained a predictive power of 85.71% for sensitivity and 73.08% for specificity, along with an AUC value of 0.875. Clinical risk factors exhibit certain predictive power on ADC and SCC prediction. Integrating these risk factors into the prediction model based on VOC biomarkers can enhance its predictive accuracy. This work indicates that exhaled breath holds the potential to precisely detect ADCs and SCCs. Considering clinical risk factors is essential when differentiating between these two subtypes.
Optical information hiding system with pixel-free expansion visual cryptography
Authors: Liu Ruize , Wu Chengzhe , Ke Changjun , Shi Yishi
Published: July 2024

We propose an optical information hiding system with pixel-free expansion visual cryptography (PEVC). In the optical concealment process, initially, a PEVC scheme is utilized to encode the secret image. This approach generates visual keys of the same size as the secret image, addressing the pixel expansion issue inherent in visual cryptography encoding schemes. As a result, it significantly reduces both storage space requirements and the network bandwidth occupied during the transmission process and exhibits a higher hidden capacity. Furthermore, PEVC is combined with the optical phase retrieval algorithm for hiding, embedding the visual keys into the phase keys. In this process, wavelength and diffraction distance are introduced as keys, enhancing the security of the system. The phase keys can be fabricated into diffractive optical elements for physical preservation and transmission in tangible form. Simulation experiments and optical experimental results indicate that the system is applicable in practical scenarios and possesses excellent security and exhibits a higher hidden capacity.
Ytterbium-doping effect on the electrochemical and piezoelectric properties of poly(vinylidene fluoride) films
Authors: Perdigon-Lagunes P , Estevez J Octavio , Zorrilla-Cangas M C , Herrera-Becerra R , Chavez-Esquivel G
Published: July 2024

The optimal molar ratio of poly(vinylidene fluoride) (PVDF): dimethyl sulfoxide (DMSO) was investigated that promoted the β-phase formation, used during the PVDF film synthesis. The solution cast method was used for doping the PVDF films with ytterbium (III) nitrate salt hexahydrate. In general, Yb-doping in PVDF films improves thermal resistance, promotes β-phase formation, modifies the monomer conformation, reduces reversibility to electrochemical processes, and increases the d33 coefficient of piezoelectricity. The β-phase formation caused by Yb-doping alters the internal structures of the trans-gauche-trans-gauche’ (TGTG’) and all-trans (TTTT) chains inside the polymeric network. The coexistence between the trans-gauche and all-trans structures provides in both films the α-phase and β-phase coexistence. The presence of self-polarized CH2-CF2 dipoles, where the concentration of fluorine remains the same and the CH2 drastically increases after Yb3+ incorporation. The quasi-reversible shape shown in both voltammetry cyclic curves is related to irreversible oxidation and reduction reactions. Yb-PVDF exhibits specific pseudocapacitance values that are 30% higher than those of the PVDF films. Finally, the piezoelectric properties were improved with ytterbium incorporation.
Investigating mechanical properties of 3D printed porous titanium scaffolds for bone tissue engineering
Authors: Yang Jiajie , Qin Chao , Lu Jianhua , Shi Xiaojian , Shi Kaibing , Cui Yiyun , Xiong Xiaqing , Wan Keming , Shen Meihua
Published: July 2024

Objective. Three-dimensional (3D) printed porous titanium scaffolds serve as a bone tissue engineering technology that offers a promising solution for addressing bone defects. The scaffold’s pore structure offers structural support and facilitates the proliferation of bone cells. Therefore, investigating the aperture and pore shape is of crucial for the development of 3D printed porous titanium scaffolds. Methods. Ti6Al4V scaffolds with the specified structure were fabricated using selective laser melting (SLM) technology. The scaffolds comprised fifteen cylindrical models measuring 20 mm in diameter and 20 mm in height. These models featured five scaffold shapes: imitation diamond-60°, imitation diamond-90°, imitation diamond-120°, regular tetrahedron and regular hexahedron. Each of these structural shapes was characterized by three different aperture sizes (400 μm, 600 μm and 800 μm). The porosity and mechanical properties of Ti6Al4V scaffolds were examined. Results. The measured porosity of Ti6Al4V scaffolds varied between 56.50% and 95.28%. The porosity increased with the size of the aperture. The mechanical properties tests revealed that, for identical apertures, the compressive strength and torsional strength were influenced by the configuration of the unit structure. Furthermore, the positive and lateral compressive strength as well as torsional strength of various unit structures exhibited distinct advantages and disadvantages. Within a uniform unit structure shape, the compressive strength and torsional strength were found to be correlated with the size of apertures, indicating that larger apertures result in decreased compressive and torsional strength. Conclusion. The configuration of the aperture and the shape of the pore were identified as significant factors that influenced the compressive strength. The compressive strength of Ti6Al4V scaffolds with various unit structure shapes exhibited both advantages and disadvantages when subjected to positive, lateral, and torsional forces. The enlarged aperture augmented the scaffold’s porosity while diminishing its compressive and torsional strength.
Numerical experimental study on combined support of bolt-arch in circular roadway
Authors: Yang Ning , Li Donghao , Zhao Meixia , Li Weiteng
Published: July 2024

The deep soft rock roadway is in high stress environment, and the surrounding rock is prone to large deformation. Appropriate roadway cross-section form and high-strength support are effective control methods for surrounding rock deformation. Circular roadway is widely used in mine engineering because of its uniform stress and deformation, which gives full play to the characteristics of rock compression and non-tension. With the advantages of high strength, high cost performance and stability, the application of arch frame in deep soft rock roadway is increasing day by day. Based on this, based on the engineering background of deep roadway in extremely soft rock in sea area, numerical experiments were carried out using the FLAC3D bolt-arch fine numerical simulation platform. The progressive failure characteristics of bolt-arch combined support in soft rock roadway are revealed. The influence law of roadway section form, geostress grade and lateral pressure coefficient on support effect is clarified. The results show that: (1) Under the condition of deep soft rock, the surrounding rock deformation of circular roadway is uniform. Compared with the straight wall semi-circular roadway, the deformation is reduced by about 86% at most. (2) The failure of arch frame in circular roadway has a significant influence on the final control effect of surrounding rock. When the ground stress exceeds 15 MPa, the loss of bearing capacity of arch frame is instantaneous, and the deformation of surrounding rock increases suddenly. (3) When the support of circular roadway in deep soft rock fails, the axial force of bolt is very small, and it basically does not play a supporting role. According to the research results, the support optimization design is carried out, and the field verification is obtained.
Masked particle modeling on sets: towards self-supervised high energy physics foundation models
Authors: Golling Tobias , Heinrich Lukas , Kagan Michael , Klein Samuel , Leigh Matthew , Osadchy Margarita , Andrew Raine John
Published: July 2024

We propose masked particle modeling (MPM) as a self-supervised method for learning generic, transferable, and reusable representations on unordered sets of inputs for use in high energy physics (HEP) scientific data. This work provides a novel scheme to perform masked modeling based pre-training to learn permutation invariant functions on sets. More generally, this work provides a step towards building large foundation models for HEP that can be generically pre-trained with self-supervised learning and later fine-tuned for a variety of down-stream tasks. In MPM, particles in a set are masked and the training objective is to recover their identity, as defined by a discretized token representation of a pre-trained vector quantized variational autoencoder. We study the efficacy of the method in samples of high energy jets at collider physics experiments, including studies on the impact of discretization, permutation invariance, and ordering. We also study the fine-tuning capability of the model, showing that it can be adapted to tasks such as supervised and weakly supervised jet classification, and that the model can transfer efficiently with small fine-tuning data sets to new classes and new data domains.
Estimating coccidioidomycosis endemicity while accounting for imperfect detection using spatio-temporal occupancy modeling
Authors: Hepler Staci A , Kaufeld Kimberly A , Kline David , Greene Andrew , Gorris Morgan E
Published: July 2024

Coccidioidomycosis, or Valley fever, is an infectious disease caused by inhaling Coccidioides fungal spores. Incidence has risen in recent years, and it is believed the endemic region for Coccidioides is expanding in response to climate change. While Valley fever case data can help us understand trends in disease risk, using case data as a proxy for Coccidioides endemicity is not ideal because case data suffer from imperfect detection, including false positives (eg, travel-related cases reported outside of endemic area) and false negatives (eg, misdiagnosis or underreporting). We proposed a Bayesian, spatio-temporal occupancy model to relate monthly, county-level presence/absence data on Valley fever cases to latent endemicity of Coccidioides, accounting for imperfect detection. We used our model to estimate endemicity in the western United States. We estimated high probability of endemicity in southern California, Arizona, and New Mexico, but also in regions without mandated reporting, including western Texas, eastern Colorado, and southeastern Washington. We also quantified spatio-temporal variability in detectability of Valley fever, given an area is endemic to Coccidioides. We estimated an inverse relationship between lagged 3- and 9-month precipitation and case detection, and a positive association with agriculture. This work can help inform public health surveillance needs and identify areas that would benefit from mandatory case reporting.

This article is part of a Special Collection on Environmental Epidemiology.
Reduction of benztropine use duration in acute psychiatry: A quality improvement initiative
Authors: Seals Whitney , Holder Mary Pat , Polancich Shea , Bryant James Edward , Birur Badari , Burk Bradley G
Published: July 2024

Purpose

Secondary to the risk of antipsychotic-induced acute dystonia, prophylactic use of benztropine is occasionally warranted but is recommended for no longer than 7 days after initiating an antipsychotic, correlating to the period of highest dystonia risk. Despite the associated increased anticholinergic burden, many clinicians continue to order benztropine for periods exceeding the recommended prophylactic duration. We investigated the reduction of benztropine use duration subsequent to implementation of truncated electronic entry orders to improve benztropine prescribing within an acute psychiatric facility.

Methods

Data were collected for psychiatric inpatients admitted between January and June 2020 who were prescribed scheduled benztropine. In a quality improvement initiative implemented in April 2022, electronic orders for benztropine were modified from a 180-day to a 7-day duration, with subsequent postintervention data collection. The primary outcomes included a change in the duration of benztropine use for any indication in the hospital, and a change in the percentage of patients meeting predetermined “unnecessary use” criteria. Secondary analyses included the percentage of patients with discharge prescriptions for scheduled benztropine (either for prophylaxis or for other indications) in the pre- and postintervention periods.

Results

73 pre- and 77 postintervention individual patients/encounters were included. Following the intervention, in-hospital duration of benztropine use for any indication decreased from a median of 14 days to a median of 7.5 days (P < 0.05), and appropriate use increased by 92.9%. The percentage of patients with prescriptions for scheduled benztropine decreased from 67.1% in the preintervention group to 29.9% in the postintervention group.

Conclusion

Decreased benztropine use duration, by means of truncated order entry sentences, during inpatient psychiatric admissions, appears feasible regardless of dual antipsychotic or first-generation antipsychotic use, and may reduce the rates of benztropine prescriptions written for discharge.