Prediction and Monitoring of the Construction Vibration Effect on an Adjacent Old Long Span Double-Convex Arch Bridge

Yu-xiong Liang,Qing-song Feng,Mei-zhen Fu,Bi-tao Wu,Jian-fei Lu,Guo-xi Tang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.5

Ground vibrations caused by the construction of impact drilling piles may affect adjacent bridges, so corresponding prediction and monitoring are necessary to ensure the safety of bridges. In this study, the construction near an existing long-span double-convex arch bridge is taken as a case study to investigate different layouts of construction machines emanating harmful ground vibrations to the existing adjacent bridge by numerical simulations and monitoring. The peak acceleration and velocity acquired from numerical simulations, and monitoring were successfully used to implement impact drilling pile construction near the existing bridge. The results show that there are good consistencies between the monitoring and numerical simulation results, and the vibration acceleration of the foundation of abutments and piers are mainly derived from the vibration caused by the construction within a distance of 50 m, while the construction beyond 50 m has little effect on the old bridge. The numbers and locations of machines near the same foundation may have a weakening or strengthening effect on the peak acceleration and velocity due to destructive and constructive interference of waves, which can help to control the effects of the vibrations of the existing adjacent bridge.

Multi-Variable and Bi-Objective Optimization of Electric Upsetting Process for Grain Refinement and Its Uniform Distribution

Guo-zheng Quan,Le Zhang,Chao An,Zhen-yu Zou 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.6

It is significant to adjust the microstructures of preforms in pursuit of high-quality exhaust valves. This work is a novel attempt to identify the optimum process parameters in electric upsetting of 3Cr20Ni10W2 high-alloy to achieve grain refinement and uniform distribution by multi-objective genetic algorithm (MOGA) optimization. A finite element (FE) model on basis of electric-thermalmechanical and macro-micro sequential multi-physics analysis methods was developed in software MSC. Mar. And different schedules of four independent process variables (heating current (I), clamping length (L), upsetting pressure (Pset) and velocity of the anvil cylinder (v)) were performed aiming to achieve two objective indicators (average grain size (dav) and inhomogeneous degree of grain distribution (σd)). Then, two objective response surfaces were constructed as the functions between the two indicators and the four independent process variables. As per the criterion that simultaneously minimize dav and σd, the processing parameters (Pset, L, v, I) were optimized by MOGA, and corresponding numerical simulation were performed. The results show that both dav and σd are improved significantly at the optimal process condition as verified by the trial-manufacture experiments, which validated the optimal design and corresponding simulation based on grain refinement and uniform distribution by MOGA was credible and effective.

Investigation into performance enhancements of Li–S batteries via oxygen-containing functional groups on activated multi-walled carbon nanotubes using Fourier transform infrared spectroscopy

Yu Hai Wang,Zhe Dai,Chao Yue Zhang,Guo Wen Sun,Zhong Wei Lu,Xiu Ping Gao,Geng Zhi Sun,Wei Lan,Zhen Xing Zhang,Xiao Jun Pan,Jin Yuan Zhou 한국물리학회 2020 Current Applied Physics Vol.20 No.9

It was demonstrated that the electrochemical performance enhancements in KOH-activated carbon materials should be mainly due to the created polar oxygen-containing functional groups (OFGs, such as such as C–O, C–– O, –OH, and O–C–– O), while the role of each OFGs on the electrochemical enhancements is still unclear. In this work, KOH activation treatments were systematically conducted on carbon nanotubes (CNTs) to explore the role of each OFG on the performance enhancements of Li–S batteries (LSBs). Results showed that the capacity of activated-CNT-sulfur (a-CNT-S) cathodes is 33% higher than that of the pristine CNT-S cathodes, and their rate capability and cycling stability are also enhanced. And the electrochemical analysis combining with Fourier transform infrared spectroscopy indicated that the formed C–O bonds are the real factor for the enhanced electrochemical performances of a-CNT-S cathodes. Furthermore, the optimal activation conditions on CNTbased cathodes for LSBs were optimized to be 10 min at 700 ℃.

Construction of Processing Maps based on Expanded Data by BP-ANN and Identification of Optimal Deforming Parameters for Ti-6Al-4V Alloy

Guo-zheng Quan,Hai-rong Wen,Jia-Pan,Zhen-yu Zou 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.2

The intrinsic relationships between deforming parameters and microstructural mechanisms for Ti-6Al-4V alloy were analyzed by processing maps. A series of thermal compression tests were carried out in the temperatures range of 1023~1323 K (across β-transus) and strain rates range of 0.01~10 s-1 on a Gleeble-3500 thermo-mechanical simulator. Based on the stress-strain data collected from compression tests, a back-propagation artificial neural network (BP-ANN) model was developed, which presents reliable performance in tracking and predicting strain-stress data. By utilizing this model, the volume of stress-strain data was expanded. According to the intensive stress-strain data, the apparent activation energy was calculated to be 564.05 kJ mol-1 and 300.20 kJ mol-1 for α+β-phase field and single β-phase field, respectively. Moreover, the processing maps were constructed at finer intervals of temperature, from which, the stable regions with higher power dissipation efficiency (η > 0.3) and unstable regions with negative instability parameter (ξ < 0) were clarified clearly. By combining processing map with microstructure observations, two main stable softening mechanisms, i.e., globularization and dynamic recovery (DRV) were identified, and globularization-predominant (0.3 < η < 0.55) parameter domain ( < 0.1 s-1) in α+β-phase field and DRV-predominant (0.25 < η < 0.41) parameter domain (0.032 s-1< <1 s-1) in β- phase field were recommended. Manuscript

매드 - 창사 문화 공원_창사, 중국

Yu Kui,Li Guo Jin,Shen Jun,Florian Pucher,Yi Wen Zhen,Li Juan,Zhao Fan,Hao Yi,Yao Mengyao 현대건축사 2006 월간 CONCEPT Vol.- No.86

Modelling of the Hot Flow Behaviors for Ti-13Nb-13Zr Alloy by BP-ANN Model and Its Application

Guo-zheng Quan,Shi-ao Pu,Zong-yang Zhan,Zhen-yu Zou,Ying-ying Liu,Yu-feng Xia 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

The plastic deformation mechanisms and the constitutive model of flow behaviors at different deformation conditions in biomedical titanium alloy are an essential step to optimize the design of any forging process for implant productions. A series of isothermal compressions tests on Ti-13Nb-13Zr alloy in a wide range of true strain, temperature and strain rate were conducted on a thermomechanical simulator. The hot flow behaviors with different softening mechanisms, including dynamic recrystallization and dynamic recovery, were characterized based on true strain-stress curves. A back-propagational artificial neural network (BP-ANN) method was conducted to evaluate and predict this non-linear problem by self-training to be adaptable to the material characteristics. The flow stress of this material a wide deformation condition range can be predicted accurately by the BP-ANN model obtained in this study. The prediction ability of this BP-ANN Model was evaluated by three accuracy indexes, Absolute error, Relative error and Average absolute relative error. Sequently, the developed BP-ANN model was programed and implanted into the finite element (FE) analysis platform, Msc.Marc software. The results have sufficiently articulated that the well-trained ANN model has excellent capability to deal with the complex flow behaviors and has great application potentiality in hot deformation processes.

개선된 단순 쇄교자속 기법을 기반으로 하는 스위치드 릴럭턴스 센서리스 구동 시스템

Zhen-Guo Li,Si-Yang Yu,이동희,안진우 대한전기학회 2012 대한전기학회 학술대회 논문집 Vol.2012 No.7

Prevalence, Risk Factors, and Psychological Effects of Overactive Bladder in Chinese University Students

Yu Liang,Guo Wei Si,Hui Jie Hu,Zhen Wei Zhang,Cui Ping Song,Qi Feng Dou,Jian Guo Wen 대한배뇨장애요실금학회 2022 International Neurourology Journal Vol.26 No.4

Purpose: The purpose of this study was to investigate the prevalence and risk factors of overactive bladder (OAB) in young adults and to explore the influence of OAB on mental health. Methods: Between October 2019 and January 2020, 14,010 anonymous questionnaires were distributed to freshmen at 2 universities in Henan, China. The students came from all over the country. The questionnaire included general items and information necessary to calculate the overactive bladder symptom score, the Chinese version of the Pittsburgh Sleep Quality Index (PSQI) score, Self-Esteem Scale (SES) score, and Self-Rating Depression Scale (SDS) score. The relationships between the prevalence of OAB and its risk factors were evaluated. Results: The overall prevalence of OAB was 6.0%, with 4.3% of participants characterized as having dry OAB and 1.7% as having wet OAB. The prevalence of mild OAB was 5.5%, and that of moderate OAB was 0.5%; no severe OAB was observed. Higher prevalence rates of OAB were found among women, respondents with constipation, and respondents with primary nocturnal enuresis (PNE) (P <0.05). Compared to healthy controls, the OAB group exhibited a higher mean SDS score (52.12±8.986 vs. 47.71±9.399, P<0.001) and mean PSQI score (5.28±2.486 vs. 4.27±2.431, P<0.001), but a lower mean SES score (27.78±3.599 vs. 29.57±4.109, P<0.001). Conclusions: OAB significantly affects the mental health of young adults. Female sex, constipation, and PNE are risk factors for OAB.

Robust Secure UAV Relay-Assisted Cognitive Communications with Resource Allocation and Cooperative Jamming

Zhen Wang,Jichang Guo,Zhiqiong Chen,Zhiqiong Chen,Lisu Yu,Yuhao Wang,Hong Rao 한국통신학회 2022 Journal of communications and networks Vol.24 No.2

This paper considers a novel scenario, where a physicallayer security issue is studied in unmanned aerial vehicles(UAVs)-assisted cognitive relay system. A secondary unmannedaerial vehicle (SUAV) relay delivers information from multiplesecondary Internet of things (IoT) devices to a secondary user(SU) under the spectrum sharing with primary users (PUs). Inthe processing of the information transmission of the SUAV relay,a secondary eavesdropper (SE) wiretaps the information transmittedby the UAV relay with imperfect location information. Inorder to confuse the SE, a friendly SUAV jammer is employedto transmit jamming signals to the SE. To prevent the SEwiretapping information as much as possible, we aim to maximizeaverage worst-case secrecy rate of the secondary relay networkby jointly optimizing robust trajectories and power of the SUAVrelay and jammer under the power, trajectories, informationcausality and multiple interference temperature (IT) thresholdconstraints. Thus, we formulate the original problem whichis a challenging non-convex problem. We propose an effectivealgorithm to solve the original problem and attain locally optimalsolution based on the successive convex approximation (SCA)technology and the alternate optimization method. Simulationsare offered to demonstrate that our proposed resource allocationscheme can effectively improve the security performance ofthe SUAV relay network in comparison with other benchmarkschemes.

Microwave absorption and photocatalytic activity of MgxZn1−x ferrite/diatomite composites

Guo Wanmi,Wang Sulei,Ren Qifang,Jin Zhen,Ding Yi,Xiong Chun-Yu,Li Jinpeng,Chen Jing,Zhu Yuelei,오원춘 한국세라믹학회 2022 한국세라믹학회지 Vol.59 No.2

Mg x Zn 1−x ferrite/diatomite composites were synthesized by a two-step combination process (hydrothermal method and mechanical mixing method). The products were characterized by X-ray diff raction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), UV–visible absorption spectrum (UV–Vis), X-ray photoelectron spectroscope (XPS), and microwave vector network analyzer. The photocatalytic results showed that the degradation rate of Rhodamine B (RhB) was 50–90% after 90 min of visible light. At 2–18 GHz frequency, when the Mg–Zn ratio increases to 0.8, the refl ection loss of a single MgxZn 1−x ferrite reaches − 7.23 dB at 8.75 GHz frequency in 3.5 mm thickness while the ratio is 0.2, the refl ection loss at 10.23 GHz reaches − 4.07 dB. The photocatalytic performance of Mgx Zn 1−x ferrite /diatomite composite for the degradation of RhB and its microwave absorption performance as absorbent are studied. The importance of developing new functional coatings to improve human environment is discussed.