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1. Causal effects of air pollutants on lung function and chronic respiratory diseases: a Mendelian randomization study

Author

Xuannian Li, Suqi Liu, Nan Jiang, Fei Xu, Huaman Liu, and Xinhua Jia

Subjects
air pollution, Mendelian randomization, inflammatory proteins, chronic respiratory diseases, lung function, Public aspects of medicine, RA1-1270
Abstract

ObjectivesOur study aims to clarify the causality between air pollutants and lung function, chronic respiratory diseases, and the potential mediating effects of inflammatory proteins.MethodWe employed Mendelian Randomization (MR) analysis with comprehensive instrumental variables screening criteria to investigate the effects of air pollutants on lung function and chronic lung diseases. Our study incorporated genetic instruments for air pollutants, ensuring F-statistics above 20.86. A total of 18 MR analyses were conducted using the inverse-variance weighted approach, along with heterogeneity and pleiotropy tests to validate the results. Mediated MR analysis was utilized to evaluate the inflammatory proteins mediating the effects of air pollutants.ResultMR analysis demonstrated significant causal interactions of particulate matter 2.5 (PM2.5), PM10, and Nitrogen dioxide (NO2) with lung function decline. Specifically, PM10 negatively affected forced expiratory volume in one second (FEV1) (OR: 0.934, 95% CI: 0.904–0.965, p = 4.27 × 10−5), forced vital capacity (FVC) (OR: 0.941, 95% CI: 0.910–0.972, p = 2.86 × 10−4), and FEV1/FVC (OR: 0.965, 95% CI: 0.934–0.998, p = 0.036). PM2.5 and NO2 were identified as potential risk factors for impairing FEV1 (OR: 0.936, 95% CI: 0.879–0.998, p = 0.042) and FEV1/FVC (OR: 0.943, 95% CI: 0.896–0.992, p = 0.024), respectively. For chronic respiratory diseases, PM2.5 and NO2 were associated with increased COPD incidence (OR: 1.273, 95% CI: 1.053–1.541, p = 0.013 for PM2.5; OR: 1.357, 95% CI: 1.165–1.581, p = 8.74 × 10−5 for NO2). Sensitivity analyses confirmed the robustness of these findings, with no significant heterogeneity or horizontal pleiotropy detected.ConclusionOur study ascertained the causal correlations of air pollutants with lung function and COPD, emphasizing the importance of reducing air pollution. Interleukin-17A mediates the reduction of FEV1 and FVC by PM10, revealing potential therapeutic targets.

Published
2024
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2. H∞ Differential Game of Nonlinear Half-Car Active Suspension via Off-Policy Reinforcement Learning

Author

Gang Wang, Jiafan Deng, Tingting Zhou, and Suqi Liu

Subjects
nonlinear active suspension, H∞ differential game, off-policy reinforcement learning, HJI equation, Mathematics, QA1-939
Abstract

This paper investigates a parameter-free H∞ differential game approach for nonlinear active vehicle suspensions. The study accounts for the geometric nonlinearity of the half-car active suspension and the cubic nonlinearity of the damping elements. The nonlinear H∞ control problem is reformulated as a zero-sum game between two players, leading to the establishment of the Hamilton–Jacobi–Isaacs (HJI) equation with a Nash equilibrium solution. To minimize reliance on model parameters during the solution process, an actor–critic framework employing neural networks is utilized to approximate the control policy and value function. An off-policy reinforcement learning method is implemented to iteratively solve the HJI equation. In this approach, the disturbance policy is derived directly from the value function, requiring only a limited amount of driving data to approximate the HJI equation’s solution. The primary innovation of this method lies in its capacity to effectively address system nonlinearities without the need for model parameters, making it particularly advantageous for practical engineering applications. Numerical simulations confirm the method’s effectiveness and applicable range. The off-policy reinforcement learning approach ensures the safety of the design process. For low-frequency road disturbances, the designed H∞ control policy enhances both ride comfort and stability.

Published
2024
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3. Gearbox Status Recognition based on TMD-SVD and POS-BP Networks Under Strong Interference

Author

Lei He and Suqi Liu

Subjects
Two-layer-mode decomposition（TMD）, Singular value decomposition（SVD）, POS-BP neural network, Fault diagnosis, Mechanical engineering and machinery, TJ1-1570
Abstract

The vehicle gearbox has a bad working environment and the fault mode is difficult to identify. On the basis of existing methods， a method based on two-layer-mode decomposition （TMD） and singular value decomposition （SVD） is proposed， combined with particle swarm （POS）-BP neural network for fault diagnosis. Firstly， the vibration signals under four typical conditions of normal transmission， rolling failure， outer ring crack and gear wear are collected on a self-built experimental platform. Then， the first 5 IMFs components of the signal is decomposed by EMD， since the spectrum of IMF1 is still complicated， the wavelet packet is used to continue the 2-layer decomposition. Finally， the eight sub-sequences are obtained by TMD， and the signal component matrix is constructed. Then， the singular value （SVD） of the component matrix is extracted as the eigenvalue， the eigenvalues are entered into the constructed POS-BP neural network diagnostic model， and the gearbox fault type is identified based on the output. The analysis results show that the method can be effectively applied to the fault diagnosis of special vehicle gearboxes， and the diagnostic accuracy rate reaches 92%， which provides an effective reference for gearbox state recognition under complex conditions.

Published
2021
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4. Assessing Future Climate Change Impacts on Potato Yields — A Case Study for Prince Edward Island, Canada

Author

Toyin Adekanmbi, Xiuquan Wang, Sana Basheer, Rana Ali Nawaz, Tianze Pang, Yulin Hu, and Suqi Liu

Subjects
potato (Solanum tuberusom), climate change, drought, food security, heat, phenology, Chemical technology, TP1-1185
Abstract

Crop yields are adversely affected by climate change; therefore, it is crucial to develop climate adaptation strategies to mitigate the impacts of increasing climate variability on the agriculture system to ensure food security. As one of the largest potato-producing provinces in Canada, Prince Edward Island (PEI) has recently experienced significant instability in potato production. PEI’s local farmers and stakeholders are extremely concerned about the prospects for the future of potato farming industries in the context of climate change. This study aims to use the Decision Support System for Agrotechnology Transfer (DSSAT) potato model to simulate future potato yields under the Coupled Model Intercomparison Project Phase 6 (CMIP6) climate scenarios (including SSP1–1.9, SSP1–2.6, SSP2–4.5, SSP3–7.0, and SSP5–8.5). The study evaluates the combined effects of changing climatic conditions at local scales (i.e., warming temperature and changing precipitation patterns) and increasing carbon dioxide (CO2) concentration in the atmosphere. The results indicate future significant declines in potato yield in PEI under the current farming practices. In particular, under the high-emission scenarios (e.g., SSP3–7.0 and SSP5–8.5), the potato yield in PEI would decline by 48% and 60% in the 2070s and by 63% and 80% by 2090s; even under the low-emission scenarios (i.e., SSP1–1.9 and SSP1–2.6), the potato yield in PEI would still decline by 6–10%. This implies that it is important to develop effective climate adaptation measures (e.g., adjusting farming practices and introducing supplemental irrigation plans) to ensure the long-term sustainability of potato production in PEI.

Published
2023
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5. Climate change impacts on global potato yields: a review

Author

Toyin Adekanmbi, Xiuquan Wang, Sana Basheer, Suqi Liu, Aili Yang, and Huiyan Cheng

Subjects
climate change, potato yield, crop model, DSSAT, food security, Meteorology. Climatology, QC851-999, Environmental sciences, GE1-350
Abstract

Potatoes as a food crop contribute to zero hunger: Sustainable Development Goal 2. Over the years, the global potato supply has increased by more than double consumption. Changing climatic conditions are a significant determinant of crop growth and development due to the impacts of meteorological conditions, such as temperature, precipitation, and solar radiation, on yields, placing nations under the threat of food insecurity. Potatoes are prone to climatic variables such as heat, precipitation, atmospheric carbon dioxide (CO _2 ), droughts, and unexpected frosts. A crop simulation model (CSM) is useful for assessing the effects of climate and various cultivation environments on potato growth and yields. This article aims to review recent literature on known and potential effects of climate change on global potato yields and further highlights tools and methods for assessing those effects. In particular, this review will explore (1) global potato production, growth and varieties; (2) a review of the mechanisms by which changing climates impact potato yields; (3) a review of CSMs as tools for assessing the impacts of climate change on potato yields, and (4) most importantly, this review identifies critical gaps in data availability, modeling tools, and adaptation measures, that lays a foundation for future research toward sustainable potato production under the changing climate.

Published
2023
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6. Gearbox Fault Diagnosis based on Improved LMD and BP Neural Network

Author

Lei He, Suqi Liu, Ting Jiang, and Zhijie Huang

Subjects
Gearbox, Mechanical engineering and machinery, TJ1-1570
Abstract

Aiming at the problem of the poor working environment and the fault mode is difficult to identify of the gearbox of military armored vehicles， based on the existing methods， the noise assisted analysis， LMD and BP neural network are combined to apply to the fault diagnosis of armored vehicle gearbox. Firstly， the vibration signals under the four typical states of normal gearbox， bearing clearance fault， indentation of outer ring and broken tooth of gear of the gearbox are collected on the self-built test bench. Then， the signal is decomposed by the noise-assisted LMD method， and the energy eigenvalues of the first eight PF components are extracted. The extracted feature values are used as the input of the BP neural network. The fault type of the gearbox is identified based on the output result. The results show that the method can be effectively applied to the fault diagnosis of military armored vehicle gearbox， and the diagnostic accuracy rate is 92.5%. An effective reference way for other special gearbox diagnosis is provided by this study， and it has certain engineering practical value.

Published
2020
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8. Comparison of Land Use Land Cover Classifiers Using Different Satellite Imagery and Machine Learning Techniques

Author

Sana Basheer, Xiuquan Wang, Aitazaz A. Farooque, Rana Ali Nawaz, Kai Liu, Toyin Adekanmbi, and Suqi Liu

Subjects
remote sensing, LULC classification, ArcGIS Pro, Google Earth Engine, machine learning, change detection, Science
Abstract

Accurate land use land cover (LULC) classification is vital for the sustainable management of natural resources and to learn how the landscape is changing due to climate. For accurate and efficient LULC classification, high-quality datasets and robust classification methods are required. With the increasing availability of satellite data, geospatial analysis tools, and classification methods, it is essential to systematically assess the performance of different combinations of satellite data and classification methods to help select the best approach for LULC classification. Therefore, this study aims to evaluate the LULC classification performance of two commonly used platforms (i.e., ArcGIS Pro and Google Earth Engine) with different satellite datasets (i.e., Landsat, Sentinel, and Planet) through a case study for the city of Charlottetown in Canada. Specifically, three classifiers in ArcGIS Pro, including support vector machine (SVM), maximum likelihood (ML), and random forest/random tree (RF/RT), are utilized to develop LULC maps over the period of 2017–2021. Whereas four classifiers in Google Earth Engine, including SVM, RF/RT, minimum distance (MD), and classification and regression tree (CART), are used to develop LULC maps for the same period. To identify the most efficient and accurate classifier, the overall accuracy and kappa coefficient for each classifier is calculated throughout the study period for all combinations of satellite data, classification platforms, and methods. Change detection is then conducted using the best classifier to quantify the LULC changes over the study period. Results show that the SVM classifier in both ArcGIS Pro and Google Earth Engine presents the best performance compared to other classifiers. In particular, the SVM in ArcGIS Pro shows an overall accuracy of 89% with Landsat, 91% with Sentinel, and 94% with Planet. Similarly, in Google Earth Engine, the SVM shows an accuracy of 87% with Landsat 8 and 92% with Sentinel 2. Furthermore, change detection results show that 13.80% and 14.10% of forest areas have been turned into bare land and urban class, respectively, and 3.90% of the land has been converted into the urban area from 2017 to 2021, suggesting the intensive urbanization. The results of this study will provide the scientific basis for selecting the remote sensing classifier and satellite imagery to develop accurate LULC maps.

Published
2022
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9. Smoke Back-Layering Phenomenon under the Combined External Wind and Stack Effects in a Staircase

Author

Man Li, Lingling Wang, Junya Chen, Zhenrong Mu, and Suqi Liu

Subjects
external wind, stack effect, staircase, open stair door, smoke back-layering, Technology, Engineering (General). Civil engineering (General), TA1-2040, Biology (General), QH301-705.5, Physics, QC1-999, Chemistry, QD1-999
Abstract

The external wind can change smoke movement patterns inside the staircase and affect smoke exhaust efficiency. This paper analyzes the smoke back-layering phenomenon in the staircase with open stair doors below the fire floor. The effect of the open stair door location and the heat release rate of fires and external wind velocities on smoke movement patterns are investigated numerically. The external wind ranges from 0–5.5 m/s. At 0 m/s, the smoke back-layering phenomenon driven by pressure difference can be found in the staircase with all stair doors closed. With the increasing wind velocity, four smoke behaviors are identified: upward moving smoke, first downward then upward moving smoke, downward moving smoke, and no smoke. Results show that the back-layering distance is mainly influenced by the external wind and heat release rate of fires. Correlations are modified and used to predict the longest back-layering distance with the first downward then upward moving smoke. This helps with arranging the smoke detectors inside a staircase and the fire safety design of high-rise buildings.

Published
2022
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11. Inter‐relay interference suppression for two‐path MIMO relay systems

Author

Xianyi Rui, Mengmeng Wang, and SuQi Liu

Subjects
interrelay interference suppression, two‐path MIMO relay systems, two‐path multiple‐input multiple‐output relay system, IRI, relay reception, transmit suppression vectors, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

A two‐path multiple‐input multiple‐output (MIMO) relay system is addressed, in which the inter‐relay interference (IRI) between two relays leads to deterioration of system performance. Transmit and receive weight vectors are employed for suppressing the IRI. Maximising the ratio between the power of the desired signal to the IRI power at the relay reception and transmission and forming a criterion function for jointly calculating the optimal receive and transmit suppression vectors, respectively. Simulation results show that the proposed scheme can improve the system performance.

Published
2016
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12. Dynamic impedance compensation for wireless power transfer using conjugate power

Author

Suqi Liu, Jianping Tan, and Xue Wen

Subjects
Physics, QC1-999
Abstract

Wireless power transfer (WPT) via coupled magnetic resonances has been in development for over a decade. However, the frequency splitting phenomenon occurs in the over-coupled region. Thus, the output power of the two-coil system achieves the maximum output power at the two splitting angular frequencies, and not at the natural resonant angular frequency. According to the maximum power transfer theorem, the impedance compensation method was adopted in many WPT projects. However, it remains a challenge to achieve the maximum output power and transmission efficiency in a fixed-frequency mode. In this study, dynamic impedance compensation for WPT was presented by utilizing the compensator within a virtual three-coil WPT system. First, the circuit model was established and transfer characteristics of a system were studied by utilizing circuit theories. Second, the power superposition of the WPT system was carefully researched. When a pair of compensating coils was inserted into the transmitter loop, the conjugate power of the compensator loop was created via magnetic coupling of the two compensating coils that insert into the transmitter loop. The mechanism for dynamic impedance compensation for wireless power transfer was then provided by investigating a virtual three-coil WPT system. Finally, the experimental circuit of a virtual three-coil WPT system was designed, and experimental results are consistent with the theoretical analysis, which achieves the maximum output power and transmission efficiency.

Published
2018
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13. Modeling of coupling mechanism of wireless power transfer system and vibration phenomenon of receiver-coil in three-coil system

Author

Suqi Liu, Jianping Tan, and Xue Wen

Subjects
Physics, QC1-999
Abstract

Wireless power transfer (WPT) via coupled magnetic resonances has become a focus recently, but the mechanisms responsible for such work are uncertain. We found that WPT system is a self-organization system by utilizing self-organization theory to judge. Firstly, the circuit model was established and transfer characteristic of a system was researched by utilizing circuit theories. Thus, with the introduction of entropy variable S, the energy equation of state can be established from the energy of the transmitter side and the energy of the receiver side. According to the energy equation of state, this paper obtains two equations when the reactance of the transmitter side and the receiver side equate to zero respectively. The vibration phenomenon of the receiver-coil in a three-coil WPT system was predicted and explained. Our findings illuminate the unusual self-organization in the WPT system and explain the vibration phenomenon of the receiver-coil in a three-coil WPT system.

Published
2017
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19. Study on the Two-Load Transmission Characteristics of a WPT System with Double Transmitting Coils.

Author

Suqi Liu, Xueying Yan, and Yuping Liu

Subjects
POWER transmission, CELL phones, COUPLINGS (Gearing), POLITICAL succession, TOPOLOGY
Abstract

It is expensive that each consuming power equipment needs to equip a separate wireless power charger. In addition, obtaining constant output power and high transfer efficiency in large coupling variation ranges is challenging. In this study, the two-load transmission characteristics of a WPT system with double transmitting coils are studied. The circuit model of the two-load WPT system is first developed, and the transmission characteristics are studied. The two-load WPT system achieving constant output power and transmission efficiency is then studied. Finally, the two-load WPT experimental system is designed. This system can achieve self-adjusting impedance compensation. Moreover, constant output power and transmission efficiency are achieved in each receiver, where their fluctuations are less than 5%. Furthermore, the utilization of the charger is improved by more than 8% due to the two receivers. This topology can provide a solution for practical application problems, such as the two-load wireless charger of the vehicle mobile phone [ABSTRACT FROM AUTHOR]

Published
2024
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26. Model-Free H∞ Output Feedback Control of Road Sensing in Vehicle Active Suspension Based on Reinforcement Learning

Author

Gang Wang, Kunpeng Li, Suqi Liu, and Hui Jing

Subjects
Control and Systems Engineering, Mechanical Engineering, Instrumentation, Computer Science Applications, Information Systems
Abstract

An active suspension system ensures the controllability of a vehicle in the vertical direction, which greatly enhances the control redundancy and safety of an intelligent driven vehicle. However, many calibrated model parameters are not conducive to the application of optimal control. To reduce the control cost of active suspension, a model-free H∞ output feedback control method is studied in this research. First, the optimal governing equation of the active suspension is transformed into a zero-sum game problem of two players, and an off-policy reinforcement learning algorithm is established to solve the game algebraic Riccati equation. This method could overcome the disadvantage of constant interactions between Q-learning and the environment. Secondly, with the consideration that some state variables are difficult to measure, a data-driven H∞ output feedback controller is designed using road sensing information and historical measurement data, and the Bellman equation of the system is solved using the least squares method to obtain the optimal control solution of the active suspension. The simulation and rapid prototype experimental results show that the proposed method could produce the optimal control strategy of the system without model parameters, overcome the strong dependence and sensitivity of traditional design methods to model parameters and improve the robust control effect of the active suspension.

Published
2023
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28. Research on Infrared Spectral Quantitative Analysis of Hydrocarbon Gases Based on Adaptive Boosting Classifier and PLS

Author

Haibo Liang, Zhongbing Li, Jinhong Guo, Yingjun Jiang, and Suqi Liu

Subjects
Boosting (machine learning), Infrared, Computer science, Component (UML), Partial least squares regression, Infrared spectroscopy, Electrical and Electronic Engineering, Spectroscopy, Biological system, Instrumentation, Spectral line, Data modeling
Abstract

The traditional gas logging using hydrogen flame gas chromatography is gradually difficult to meet the requirements of the current complex oil and gas reservoir exploration because of its long detection cycle, many additional equipment, complex use, maintenance process and other defects. Infrared spectroscopy has obvious advantages in detection speed and convenience. But when it comes to homologues with similar molecular structure, it is difficult to quantitatively analyze the component concentration because of the serious overlap of characteristic absorption peaks. To solve this problem, this paper uses the self-developed experimental platform to carry out a large number of infrared spectral experimental studies on the single substance and six component mixtures. Based on a large number of experimental data, a method combining the AdaBoost classifier with optimization window partial least squares (PLS) modeling is proposed. Through the PLS local modeling for the spectra of different components and different concentration ranges, the boosting algorithm is used to classify the original spectral data, and then the component concentration is calculated. This method solves the problems of difficult identification and inaccurate quantitative analysis of alkane mixed gas components in traditional methods, and effectively improves the detection accuracy of infrared spectrum quantitative analysis of mixed components, which provides the core theoretical support for infrared spectroscopy to replace hydrogen flame gas chromatography which is widely used in gas logging.

Published
2021
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29. Research on Human Motion Monitoring Method Based on Multi-Joint Constraint Filter Model

Author

Tao Luo, Suqi Liu, Lei Zhao, Hai Yang, Jialing Zou, and Haibo Liang

Subjects
Optimal estimation, Computer science, System of measurement, 010401 analytical chemistry, Gyroscope, Kalman filter, Accelerometer, Sensor fusion, 01 natural sciences, 0104 chemical sciences, law.invention, Constraint (information theory), Extended Kalman filter, law, Control theory, Electrical and Electronic Engineering, Instrumentation
Abstract

In recent years, with the increasing application of human motion monitoring technology in virtual reality, medical health, human-computer interaction, and other fields, higher requirements have been put forward for measurement accuracy. Aiming at the problem of large accumulative measurement error and multi-joint constraint in the traditional inertial measurement system, a multi-joint constrained filter model human motion monitoring method based on data fusion is proposed. Firstly, an accelerometer and magnetometer are used to construct the initial attitude angle calculation model of the human body at rest. Secondly, combined with gyroscope, accelerometer and magnetometer, the attitude optimal estimation model based on Extended Kalman Filter (EKF) algorithm for human body motion was established. Then, a global coordinate system of human multi-joints is established, and the joint constraint is introduced into the attitude optimal estimation model by using the estimation projection method, and the multi-joint constraint filtering model of human motion monitoring is constructed. Finally, a multi-inertial measurement unit (MIMU) human motion monitoring system was built, and the simulation and experimental analysis were carried out. The experimental results show that the maximum angular measurement error is about 1° after filtering with the motion monitoring method proposed in this paper. Compared with the existing algorithm, the accuracy of the three angle measurements is improved by 38.2%, 39.3% and 67.4%, respectively. Based on this, the human motion monitoring system designed can effectively monitor human motion.

Published
2021
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31. Research on the Calibration Method of MWD Under the Cooperation of Multiple Models

Author

Haibo Liang, Li Li, Yue Rao, Hai Yang, Tao Luo, Suqi Liu, and Muhammad Junaid Kan

Subjects
Field (physics), Computer science, 010401 analytical chemistry, Flux, Drilling, Interference (wave propagation), 01 natural sciences, 0104 chemical sciences, Magnetic field, Control theory, Electromagnetic shielding, Calibration, Measurement while drilling, Inclinometer, Electrical and Electronic Engineering, Instrumentation
Abstract

The accurate calculation of the attitude angle of the down-hole bit is the key technology to realize the automation and intelligence in the field of oil drilling. Therefore, in recent years, Measurement while drilling (MWD) has been widely recognized and rapidly developed in the field of precise target drilling. In order to solve the problem of azimuth error caused by the interference of the flux gate sensor by the fixed magnetic field and the induced magnetic field in the process of solving the attitude angle of the inclinometer, this paper proposes a calibration method of the inclinometer while drilling under the cooperation of multiple models. Firstly, the error analysis is carried out for the interference magnetic field of flux gate sensor. Secondly, the error compensation is carried out for the fixed magnetic field and the induced magnetic field respectively by using the ellipsoid fitting algorithm under the proposed limited conditions and the Newton iterative model under the magnetic shielding coefficient solution. Thirdly, the magnetic field environment during drilling is simulated by building an experimental platform composed of calibration frame and inclinometer carry out experimental verification. Finally, the experimental results show that compared with the accuracy of azimuth before error compensation, the maximum error of azimuth is reduced to 0.486° and the accuracy is increased to 98.58%. Thus, the interference of a fixed magnetic field and induced magnetic field on inclinometer is effectively suppressed, and the correctness and feasibility of the method proposed in this paper are verified.

Published
2021
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33. Transfer characteristics of the MCR-WPT system using two series transmitting coils

Author

Yuping Liu and Suqi Liu

Subjects
010302 applied physics, Physics, business.industry, 020208 electrical & electronic engineering, Electrical engineering, Topology (electrical circuits), 02 engineering and technology, 01 natural sciences, Industrial and Manufacturing Engineering, Power (physics), Experimental system, Electromagnetic coil, Transfer (computing), 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Wireless power transfer, Electrical and Electronic Engineering, Constant (mathematics), business, Electrical impedance
Abstract

PurposeThe impedance compensation approaches have been adopted to achieve the maximum output power and transfer efficiency in many magnetic coupling resonance wireless power transfer projects. However, it remains a challenge to obtain the constant output power and transfer efficiency in a fixed-frequency mode during variations in transfer distance and orientation of the coils. In this paper, using two series transmitting coils to achieve the constant output power and transfer efficiency is used.Design/methodology/approachFirst, the circuit model is established and transfer characteristics are studied. Second, using the two series transmitting coils to achieve the constant output power and transfer efficiency is investigated. Finally, the experimental system is designed; it can optimize the transfer performances by itself; the constant output power and transfer efficiency are achieved in the fixed-frequency mode.FindingsWhen the receiving coil moves between the two series transmitting coils, the tolerance of the output power and transfer efficiency is less than 5 per cent.Research limitations/implicationsWhen a receiving coil is placed between the two series transmitting coils, there are space limits. The receiving coil only shifts between the two transmitting coils.Practical implicationsHowever, the rail guide vehicle may achieve constant output power and transfer efficiency when it moves on the rail guide. So, this topology may provide a practical solution.Originality/valueIn this research, the three-coil MCR-WPT system including two series transmitting coils is presented. In a fixed-frequency mode, the constant output power and transfer efficiency is achieved in experiments during variations in transfer distance and orientation of the coils. The fluctuation of the output power and transfer efficiency is less than 5 per cent.

Published
2019
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34. Examining an Alternative Molecular Mechanism To Toughen Glassy Polymers

Author

Suqi Liu, Masoud Razavi, Hailan Guo, Shi-Qing Wang, and Da Huang

Subjects
chemistry.chemical_classification, Nanocomposite, Materials science, Polymers and Plastics, Organic Chemistry, Rubber toughening, 02 engineering and technology, Polymer, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Inorganic Chemistry, Chemical engineering, chemistry, Materials Chemistry, Molecular mechanism, 0210 nano-technology, Mechanism (sociology)
Abstract

Contrasting the conventional rubber-toughening mechanism, we show that the new PMMA-based rubber-toughened nanocomposite (PMMA-rt/nc) achieves the desired rubber toughening through molecular-level ...

Published
2019
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35. A Shared Parking Space Optimization Model to Alleviate China’s Parking Problem Considering Travelers’ Tiered Credit Risk

Author

Ying Tao, Suqi Liu, and Changmin Li

Subjects
Operations research, Computer science, Parking problem, ComputingMilieux_LEGALASPECTSOFCOMPUTING, Transportation, Shared parking, Space optimization, China, Credit risk
Abstract

A shared parking space optimization (SPSO) model is established to alleviate China’s parking problem considering travelers’ tiered credit risk. The SPSO model has the following characteristics: tra...

Published
2019
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36. Using uniform magnetic field to obtain the constant output power and transfer efficiency for MCR-WPT

Author

Suqi Liu and Jianping Tan

Subjects
010302 applied physics, Physics, business.industry, 020208 electrical & electronic engineering, Topology (electrical circuits), 02 engineering and technology, Topology, 01 natural sciences, Industrial and Manufacturing Engineering, Power (physics), law.invention, Battery charger, Relay, law, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Wireless, Maximum power transfer theorem, Wireless power transfer, Electrical and Electronic Engineering, Constant (mathematics), business
Abstract

PurposeThis paper aims to find an approach that achieves constant output power and transfer efficiency in an open space, such as charging pads.Design/methodology/approachIn this study, a topology of the five-coil system including two transmitting coils is presented. Also, in a fixed-frequency mode and an open space, this study focuses on the two transmitting coils to achieve the uniform magnetic field and ultimately, attain the constant output power and transfer efficiency.FindingsIn a fixed-frequency mode and an open space, the constant output power and transfer efficiency is then achieved in experiments by inserting the relay loop into the uniform magnetic field.Practical implicationsAn approach that achieves constant output power and transfer efficiency in an open space. The topology of the five-coil magnetically coupled resonant-wireless power transfer (MCR-WPT) system shows prospective value for various applications, which could be used at designing of wireless battery charger dedicated for cars or mobile phones.Originality/valueBy comparing the simulation and experimental results, the topology can be optimized in the transmission performance by itself. By doing so, the constant output power and transfer ef?ciency are achieved in the constant frequency mode.

Published
2019
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37. Electrospinning Polymer Nanofibers With Controlled Diameters

Author

Suqi Liu, Kevin L. White, and Darrell H. Reneker

Subjects
chemistry.chemical_classification, Materials science, Polyacrylonitrile, Nanotechnology, 02 engineering and technology, Polymer, Conductivity, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Polyvinylidene fluoride, Industrial and Manufacturing Engineering, Electrospinning, 0104 chemical sciences, Surface tension, chemistry.chemical_compound, chemistry, Control and Systems Engineering, Electrospun nanofibers, Nanofiber, Electrical and Electronic Engineering, 0210 nano-technology
Abstract

Rapidly growing needs for large-scale industrial production of polymer nanofibers produced by electrospinning require better control of electrospinning. In this paper, the capability of electrospinning polymer nanofibers with desired diameter and morphology was demonstrated. Concentration of the polymer solution, together with electrical conductivity and surface tension of the polymer solution, were adjusted to control the diameter and morphology of electrospun nanofiber. Nanofibers of polyacrylonitrile and polyvinylidene fluoride were successfully electrospun, with average diameters in the range from 100 to 400 nm. Real-time optical and electrical observations of electrospinning phenomena and adjustments of experimental variables in an electrospinning process contribute to a feedback system for online controlled electrospinning, which requires a multidisciplinary approach including chemistry, electrical engineering, and material science.

Published
2019
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38. Droplet-jet shape parameters predict electrospun polymer nanofiber diameter

Author

Suqi Liu and Darrell H. Reneker

Subjects
chemistry.chemical_classification, Jet (fluid), Materials science, Polymers and Plastics, Organic Chemistry, Physics::Optics, 02 engineering and technology, Polymer, 010402 general chemistry, 021001 nanoscience & nanotechnology, Curvature, 01 natural sciences, Electrospinning, Shape parameter, 0104 chemical sciences, Physics::Fluid Dynamics, chemistry, Electrospun nanofibers, Nanofiber, Materials Chemistry, Composite material, 0210 nano-technology, Voltage
Abstract

Correlations between observable features of the droplet-jet shape and the diameter of electrospun nanofiber were studied. Three shape parameters derived from optical images of the jet transforming from a droplet were identified. They are “L-R curvature”, “initial jet diameter”, and “transition slope”. Nanofiber diameter increased as the observed value of each shape parameter increased. The correlation between “initial jet diameter” and fiber diameter, as well as the correlation between “transition slope” and fiber diameter, were not affected by the variation of voltage or concentration of the polymer solution. “Initial jet diameter” and “transition slope” have potential applications in online controlled electrospinning to predict nanofiber diameter as real-time feedback information to guide the control of electrospun nanofiber diameter.

Published
2019
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39. ACHIEVING THE CONSTANT OUTPUT POWER AND TRANSFER EFFICIENCY OF A MAGNETIC COUPLING RESONANCEWIRELESS POWER TRANSFER SYSTEM BASED ON THE MAGNETIC FIELD SUPERPOSITION PRINCIPLE

Author

Suqi Liu, and Yuping Liu, and Jianping Tan

Subjects
Physics, Superposition principle, Transfer efficiency, Quantum electrodynamics, Maximum power transfer theorem, Condensed Matter Physics, Constant (mathematics), Inductive coupling, Electronic, Optical and Magnetic Materials, Magnetic field, Power (physics)
Published
2019
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41. Dynamic impedance compensation for WPT using a compensator in a three-coil wireless power transfer system

Author

Suqi Liu and Jianping Tan

Subjects
Angular frequency, Computer science, 020208 electrical & electronic engineering, 020206 networking & telecommunications, Topology (electrical circuits), 02 engineering and technology, Industrial and Manufacturing Engineering, law.invention, Compensation (engineering), Power (physics), Control theory, Electromagnetic coil, Relay, law, 0202 electrical engineering, electronic engineering, information engineering, Wireless power transfer, Electrical and Electronic Engineering, Energy (signal processing)
Abstract

Purpose The purpose of this paper is to study the wireless power transfer (WPT) system that always achieves the maximum output power at a fixed angular frequency using the dynamic impedance compensation and also the maximum transfer efficiency. Design/methodology/approach An efficient topology of the WPT system is proposed which states that the functions of the relay are transformed into the functions of the compensator in the three-coil WPT system. Findings Increasing the ratio of the frequency detuning factor of the compensator relative to the frequency detuning factor of the compensator also causes the curves of the normalized output power and the transfer efficiency to move toward the high frequency direction. Practical implications The scheme of the dynamic compensation for the WPT using a compensator is convenient to obtain the dynamic impedance compensation by adding or removing the capacitances or inductances from the compensator. Originality/value The functions of the relay are transformed into the functions of the compensator in the three-coil WPT system.

Published
2018
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42. STUDY ON THE VIBRATION MECHANISM OF THE RELAY COIL IN A THREE-COIL WPT SYSTEM

Author

Jianping Tan and Suqi Liu

Subjects
Computer science, Acoustics, 020208 electrical & electronic engineering, 020206 networking & telecommunications, 02 engineering and technology, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, law.invention, Vibration, Mechanism (engineering), Electromagnetic coil, Relay, law, 0202 electrical engineering, electronic engineering, information engineering
Published
2018
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43. Internet Finance Innovation and Transformation of Traditional Banks in the Era of Big Data

Author

Suqi Liu, Mengjia Wang, Yan Tian, and Ge An

Subjects
Hospital information system, Medical treatment, business.industry, Medical record, Spontaneous reporting, Big data, medicine, The Internet, Business, medicine.disease, Data science, Field (computer science), Adverse drug reaction
Abstract

To explore the application of data mining technology in adverse drug reaction (ADR), and provide reference for exploring new methods in the field of ADR monitoring in China. Searching for database related documents such as China Knowledge Network and Data with keywords such as “data mining”, “adverse drug reaction”, “electronic medical record” and “hospital information system”, data mining in spontaneous reporting system and electronic medical treatment the current status, common methods, advantages and disadvantages of ADR monitoring are reviewed. Data mining technology can effectively detect ADR signals in both spontaneous reporting systems and electronic medical records. It has excellent data analysis and ability to discover patterns and will play an important role in the field of ADR monitoring.

Published
2020
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44. Controlled electrospinning to produce polymer nanofibers with specified diameters

Author

Darrell H. Reneker, Kevin L. White, and Suqi Liu

Subjects
chemistry.chemical_classification, Materials science, Polyacrylonitrile, 02 engineering and technology, Polymer, Conductivity, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Polyvinylidene fluoride, Electrospinning, 0104 chemical sciences, Surface tension, chemistry.chemical_compound, chemistry, Nanofiber, Polymer solution, Composite material, 0210 nano-technology
Abstract

Rapidly growing needs for large-scale industrial production of polymer nanofibers produced by electrospining require better control on electrospinning. Essential electrical aspects of electrospinning are often ignored. Observations of electrical phenomenon and adjustments of experimental variables in an electrospinning process are needed to create a feedback system for controlled electrospinning. In this paper, conductivity of the polymer solution, together with concentration and surface tension of the polymer solution, were adjusted to conduct controlled electrospinning. Nanofibers of polyacrylonitrile and polyvinylidene fluoride were successfully electrospun, with specified diameters in the range from 100 nm to 400 nm.

Published
2017
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45. INHIBITION OF INSECT GLUTATHIONE S-TRANSFERASE (GST) BY CONIFER EXTRACTS

Author

Brendan Walshe-Roussel, Ammar Saleem, Luis A. Cáceres, John T. Arnason, Ian M. Scott, Zhiling Wang, Andrew Waye, Zhong Zhao, Rui Liu, Qin Wei, Mamdouh M. Abou-Zaid, and Suqi Liu

Subjects
chemistry.chemical_classification, biology, Physiology, fungi, Colorado potato beetle, Flavonoid, General Medicine, Glutathione, biology.organism_classification, Biochemistry, Black spruce, chemistry.chemical_compound, Glutathione S-transferase, chemistry, Insect Science, visual_art, Botany, visual_art.visual_art_medium, biology.protein, Taxifolin, Bark, Abies balsamea
Abstract

Insecticide synergists biochemically inhibit insect metabolic enzyme activity and are used both to increase the effectiveness of insecticides and as a diagnostic tool for resistance mechanisms. Considerable attention has been focused on identifying new synergists from phytochemicals with recognized biological activities, specifically enzyme inhibition. Jack pine (Pinus banksiana Lamb.), black spruce (Picea mariana (Mill.) BSP.), balsam fir (Abies balsamea (L.) Mill.), and tamarack larch (Larix laricina (Du Roi) Koch) have been used by native Canadians as traditional medicine, specifically for the anti-inflammatory and antioxidant properties based on enzyme inhibitory activity. To identify the potential allelochemicals with synergistic activity, ethanol crude extracts and methanol/water fractions were separated by Sephadex LH-20 chromatographic column and tested for in vitro glutathione S-transferase (GST) inhibition activity using insecticide-resistant Colorado potato beetle, Leptinotarsa decemlineata (Say) midgut and fat-body homogenate. The fractions showing similar activity were combined and analyzed by ultra pressure liquid chromatography-mass spectrometry. A lignan, (+)-lariciresinol 9′-p-coumarate, was identified from P. mariana cone extracts, and L. laricina and A. balsamea bark extracts. A flavonoid, taxifolin, was identified from P. mariana and P. banksiana cone extracts and L. laricina bark extracts. Both compounds inhibit GST activity with taxifolin showing greater activity compared to (+)-lariciresinol 9′-p-coumarate and the standard GST inhibitor, diethyl maleate. The results suggested that these compounds can be considered as potential new insecticide synergists.

Published
2014
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46. Facial synthesis of SnO2 nanoparticle film for efficient fiber-shaped dye-sensitized solar cells

Author

Xiao Yu, Ming Peng, Xin Cai, Bing Deng, Kafafy Hany, Dechun Zou, Yongping Fu, and Suqi Liu

Subjects
Materials science, Renewable Energy, Sustainability and the Environment, business.industry, Energy Engineering and Power Technology, chemistry.chemical_element, Nanoparticle, Nanotechnology, Substrate (electronics), Hybrid solar cell, Dye-sensitized solar cell, chemistry, Optoelectronics, Shielding effect, Fiber, Electrical and Electronic Engineering, Physical and Theoretical Chemistry, business, Tin, Titanium
Abstract

SnO2 nanoparticle film is directly prepared by in situ thermal calcining isopropanol solution of tin tetraisopropoxide, and is used to construct the SnO2–TiO2 junction on titanium wire substrate. The titanium wire supported SnO2–TiO2 junction is further applied to fiber-shaped dye-sensitized solar cells (FDSCs). High efficiency of 5.8% (Normal Model) and 12.4% (Diffuse Model) are achieved. Our results indicate that Jsc enhancement derived by SnO2–TiO2 junction and the recombination shielding effect of the compact TiO2 film could synergistically contribute to high efficiencies. This study offers a novel and alternative strategy for achieving efficient SnO2–TiO2 junction based solar cells in a facile, scalable and cost-effective way.

Published
2014
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47. Conifer flavonoid compounds inhibit detoxification enzymes and synergize insecticides

Author

Qin Wei, Zhiling Wang, Xiaofei Cheng, Suqi Liu, Ian M. Scott, and Zhong Zhao

Subjects
0106 biological sciences, 0301 basic medicine, Insecticides, Health, Toxicology and Mutagenesis, Pyrethrum, Flavonoid, 01 natural sciences, Esterase, 03 medical and health sciences, chemistry.chemical_compound, Taxifolin, Animals, Glutathione Transferase, chemistry.chemical_classification, Flavonoids, biology, Colorado potato beetle, Esterases, General Medicine, biology.organism_classification, Coleoptera, 010602 entomology, Tracheophyta, 030104 developmental biology, Glutathione S-transferase, chemistry, Biochemistry, Enzyme inhibitor, biology.protein, Esterase inhibitor, Agronomy and Crop Science
Abstract

Detoxification by glutathione S-transferases (GSTs) and esterases are important mechanisms associated with insecticide resistance. Discovery of novel GST and esterase inhibitors from phytochemicals could provide potential new insecticide synergists. Conifer tree species contain flavonoids, such as taxifolin, that inhibit in vitro GST activity. The objectives were to test the relative effectiveness of taxifolin as an enzyme inhibitor and as an insecticide synergist in combination with the organophosphorous insecticide, Guthion (50% azinphos-methyl), and the botanical insecticide, pyrethrum, using an insecticide-resistant Colorado potato beetle (CPB) Leptinotarsa decemlineata (Say) strain. Both taxifolin and its isomer, quercetin, increased the mortality of 1(st) instar CPB larvae after 48h when combined with Guthion, but not pyrethrum. Taxifolin had greater in vitro esterase inhibition compared with the commonly used esterase inhibitor, S, S, S-tributyl phosphorotrithioate (DEF). An in vivo esterase and GST inhibition effect after ingestion of taxifolin was measured, however DEF caused a greater suppression of esterase activity. This study demonstrated that flavonoid compounds have both in vitro and in vivo esterase inhibition, which is likely responsible for the insecticide synergism observed in insecticide-resistant CPB.

Published
2015

49. Achieving the Constant Output Power and Transfer Efficiency of a Magnetic Coupling Resonance Wireless Power Transfer System Based on the Magnetic Field Superposition Principle.

Author

Suqi Liu, Jianping Tan, and Yuping Liu

Subjects
WIRELESS power transmission, MAGNETIC coupling, SUPERPOSITION principle (Physics), MAGNETIC resonance, MAGNETIC fields, POLITICAL succession
Abstract

The output power of a magnetic coupling resonance wireless power transfer (MCR-WPT) system attains the maximum value at two frequencies splitting in an over-coupled region. To achieve suitable transfer characteristics, impedance compensation methods have been used in MCR-WPT domain. In securing the constant output power and transfer efficiency in a constant frequency mode, a topology of the MCR-WPT system with two transmitting coils is employed. First, the circuit model is designed while evaluating the transmission characteristics. Second, when the two transmitting coils are placed into the transmitting loop, the main transmitter and sub-transmitter loops are created by sharing the same transmitter. The use of two transmitting coils to achieve a magnetic field superposition is investigated. Constant output power and transfer efficiency are then investigated in a constant frequency mode. Finally, the experimental equipment is designed. Experimental results confirm the effectiveness and robustness of the topology. Such a topology can be optimized for the transfer performance by itself and can achieve constant output power and transfer efficiency. If the distance between the two transmitting coils is appropriate and the receiving coil moves between the two transmitting coils, the fluctuation of the output power and transfer efficiency of the MCR-WPT system is less than 5%. [ABSTRACT FROM AUTHOR]

Published
2019
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50. Inhibition of insect glutathione S-transferase (GST) by conifer extracts

Author

Zhiling, Wang, Zhong, Zhao, Mamdouh M, Abou-Zaid, John T, Arnason, Rui, Liu, Brendan, Walshe-Roussel, Andrew, Waye, Suqi, Liu, Ammar, Saleem, Luis A, Cáceres, Qin, Wei, and Ian M, Scott

Subjects
Insecticides, Plant Extracts, Fat Body, Pesticide Synergists, Lignans, Coleoptera, Gastrointestinal Tract, Insecticide Resistance, Tracheophyta, Larva, Animals, Quercetin, Enzyme Inhibitors, Glutathione Transferase
Abstract

Insecticide synergists biochemically inhibit insect metabolic enzyme activity and are used both to increase the effectiveness of insecticides and as a diagnostic tool for resistance mechanisms. Considerable attention has been focused on identifying new synergists from phytochemicals with recognized biological activities, specifically enzyme inhibition. Jack pine (Pinus banksiana Lamb.), black spruce (Picea mariana (Mill.) BSP.), balsam fir (Abies balsamea (L.) Mill.), and tamarack larch (Larix laricina (Du Roi) Koch) have been used by native Canadians as traditional medicine, specifically for the anti-inflammatory and antioxidant properties based on enzyme inhibitory activity. To identify the potential allelochemicals with synergistic activity, ethanol crude extracts and methanol/water fractions were separated by Sephadex LH-20 chromatographic column and tested for in vitro glutathione S-transferase (GST) inhibition activity using insecticide-resistant Colorado potato beetle, Leptinotarsa decemlineata (Say) midgut and fat-body homogenate. The fractions showing similar activity were combined and analyzed by ultra pressure liquid chromatography-mass spectrometry. A lignan, (+)-lariciresinol 9'-p-coumarate, was identified from P. mariana cone extracts, and L. laricina and A. balsamea bark extracts. A flavonoid, taxifolin, was identified from P. mariana and P. banksiana cone extracts and L. laricina bark extracts. Both compounds inhibit GST activity with taxifolin showing greater activity compared to (+)-lariciresinol 9'-p-coumarate and the standard GST inhibitor, diethyl maleate. The results suggested that these compounds can be considered as potential new insecticide synergists.

Published
2014

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