Femtosecond Photoelectron Imaging of N2 at 410 nm

Wei Guo,Shanshan Wei,Xingqiang Lu,Li Wang 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.12

We experimentally measure the kinetic energy and angular distributions of photoelectrons of N2 as a function of 410 nm femtosecond laser intensity by using velocity map imaging technique. The strong-field multiphoton ionization of molecules shares many of the characteristics with those of atoms. Electron kinetic energies are nearly independent of laser intensities. The independence suggests that the electron peaks in the photoelectron spectrum actually result from a twostep process, indicative of the occurrence of real population in the intermediate states. The relative amplitudes of electron peaks indicate that in the two-step process, nonresonant population transfer dominates for low intensities, while resonant population transfer dominates for higher intensities.

A new hybrid method for bearing fault diagnosis based on CEEMDAN and ACPSO-BP neural network

Shanshan Song,Shuqing Zhang,Wei Dong,Xiaowen Zhang,Wei Ma 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.11

As an important part of rotating machinery, the failure of bearings will cause serious vibration and noise of mechanical equipment, which will affect the normal operation of the equipment and even lead to economic losses and casualties. To accurately and efficiently diagnose the working state and fault category of bearings, a new fault diagnosis method for rolling bearings based on the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN), weighted permutation entropy (WPE) and adaptive chaotic particle swarm optimization back propagation (BP) neural network (ACPSO-BP) was proposed. CEEMDAN and WPE were used to extract fault features and optimize the feature vector by mean domain specification principles. ACPSO optimizes the convergence speed and recognition accuracy of the BP neural network by introducing an adaptive tent mapping interval. The experimental results on bearing data from Western Reserve University and actual wind turbine data show that the proposed diagnosis method can achieve high fault recognition accuracy with a small number of training samples.

Femtosecond Photoelectron Imaging of N₂ at 410 nm

Guo, Wei,Wei, Shanshan,Lu, Xingqiang,Wang, Li Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.12

We experimentally measure the kinetic energy and angular distributions of photoelectrons of $N_2$ as a function of 410 nm femtosecond laser intensity by using velocity map imaging technique. The strong-field multiphoton ionization of molecules shares many of the characteristics with those of atoms. Electron kinetic energies are nearly independent of laser intensities. The independence suggests that the electron peaks in the photoelectron spectrum actually result from a two-step process, indicative of the occurrence of real population in the intermediate states. The relative amplitudes of electron peaks indicate that in the two-step process, nonresonant population transfer dominates for low intensities, while resonant population transfer dominates for higher intensities.

A glassy carbon electrode modified with a composite consisting of electrodeposited chitosan and carboxylated multi‑walled carbon nanotubes for simultaneous voltammetric determination of dopamine, serotonin and melatonin

Shanshan Tang,Axin Liang,Miao Liu,Wei Wang,Fulai Zhang,Aiqin Luo 한국탄소학회 2023 Carbon Letters Vol.33 No.7

A glassy carbon electrode modified with a composite consisting of electrodeposited chitosan and carboxylated multi-walled carbon nanotubes (e-CS/MWCNTs/GCE) was used as a working electrode for simultaneous determination of dopamine (DA), serotonin (5-HT) and melatonin (MT), which were related to circadian rhythms. The electrochemical characterizations of the working electrode were carried out via electrochemical impedance spectroscopy and chronocoulometry. It was found that electrochemical modification method, that was cyclic voltammetry, may can cause continuous CS polymerization on MWCNTs surface to form a dense membrane with more active sites on the electrode, and the electrochemically active surface area of e-CS/MWCNTs/GCE obtained was about 7 times that of GCE. The electrochemical behaviour of DA, 5-HT and MT on working electrode were carried out via differential pulse voltammetry and cyclic voltammetry. The results showed that e-CS/MWCNTs/GCE solved the problem that the bare electrode could not detect three substances simultaneously, and can catalyze oxidation potential difference as low as 0.17 V of two substances reaction at the same time, indicating very good electrocatalytic activity. By optimizing the detection conditions, the sensor showed a good linear response to DA, 5-HT and MT in the range of 20-1000 μmol/L, 9-1000 μmol/L and 20-1000 μmol/L, and the detection limits were 12 μmol/L, 10 μmol/L and 22 μmol/L (S/N = 3), respectively. In addition, the proposed sensor was successfully applied to the simultaneous detection of DA, 5-HT and MT in human saliva samples.

A modified method to emergetic ecological footprint and its application

Shanshan Tai,Yuanman Hu,Mial Liu,Weidong Zhang,Wei Wang 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

The ecological footprint created by Wackernagel and Rees is a largely heuristic tool for evaluation the sustainability of a system and has been applied widely in economic and ecological researches. The emergetic ecological footprint indicator which created by Zhao et al. was based on emergy analysis created by Odum H.T. through combining emergy analysis into ecological footprint. It was used for evaluating sustainability of an ecosystem through flow. The aim of this paper is to show a modified form of emergetic ecological footprint by using yields of regional biological resources to substitute biological resources consumptions. To demonstrate the mechanics of this new method, we compared our calculation with the calculations of conventional ecological footprint and emergetic ecological footprint of a regional case. We select Dalian city of Liaoning province in northeast China, as an example for application of our study, and calculate ecological footprint, ecological carrying capacity, ecological overshoot, ecological footprint intensity index and ecological overshoot index. In this case the same conclusions were drawn using all methods: dalian city an ecological overshoot.

Pervaporation properties of polyvinyl alcohol/ceramic composite membrane for separation of ethyl acetate/ethanol/water ternary mixtures

Shanshan Xia,Wanqin Jin,Wang Wei,Gongping Liu,Xueliang Dong 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.2

In further purification of ethyl acetate (EAC) process, azeotropic distillation or extractive distillation is usually applied. High energy consumption limits the economic profit of the process. In this study, pervaporation separation of EAC/ethanol (EA)/water ternary mixtures using the ceramic-supported polyvinyl alcohol (PVA) composite membrane was investigated to substitute the azeotropic distillation or extractive distillation. Swelling experiments were performed to evaluate the sorption characteristic of the membrane. Flory-Huggins theory was applied to study the interaction between the membrane and the penetrant. The UNIFAC model was adopted to investigate the variation of the penetrant activity in the membrane. The effects of operation temperature, feed water content and feed flow rate on the PV performance of the membrane were systematically investigated. The composite membrane exhibited high PV performance with the total flux of 2.1 kg·m−2·h−1 and 94.9 wt% permeate concentration of water (operation condition:feed composition 82.6 wt% EAC, 8.4 wt% EA, 9 wt% water, feed temperature 60 oC, feed flow rate 252 mL·min−1). The PV performance of the membrane varied slightly over a continuous PV experiment period of 110 h. Our results demonstrated that the PVA/ceramic membrane was a potential candidate for the purification of EAC/EA/water ternary mixtures.

Study on land ecological risk in Shen-Fu Connection Area based on land use change

Wei Wang,Jinghai Zhu,Yuanman Hu,Weiling Liu,Shanshan Tai 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

Taking Shen-Fu Connection Area (SFCA) as a case, the purpose of this study is to analyze the characteristics of ecological risk based on land use change. Methods of RS, GIS and statistical analysis were employed. An integrated ecological risk index was built to analyze the ecological risk to landscape change in this region. The results show that the conversion of land type is mainly among agricultural land, construction land and fores land and it can strongly influence the characteristic and distribution of ecological risk, so the integrated ecological risk has been increasing from 1997 to 2008. With the economic development and urbanization course, the degree of land use will be increased and so is the ecological risk. So ecological construction and environment protection should be adopted in this area for sustainable development.

NF-jB activation was involved in reactive oxygen speciesmediated apoptosis and autophagy in 1-oxoeudesm-11(13)-eno- 12,8a-lactone-treated human lung cancer cells

Shanshan Liu,Di Wu,Lin Li,Xiao Sun,Wei-Dong Xie,Xia Li 대한약학회 2014 Archives of Pharmacal Research Vol.37 No.8

1-oxoeudesm-11(13)-eno-12,8a-lactone (OEL),a novel eudesmane-type sesquiterpene compound, has beenshown to inhibit the growth of some cancer cell lines andinduce significant apoptosis. Here, we investigated the anticanceractivities of OEL in human lung cancer cells. Ourstudies demonstrated that OEL induced both apoptosis andautophagy in A549 and H460 cells. OEL-induced autophagywas assessed by appearance of autophagic vacuoles,formation of acidic vesicular organelles, conversion ofLC3-I to LC3-II, recruitment of LC3-II to the autophagosomes,and activation of autophagy genes. Furthermore,administration of autophagic inhibitor 3-methyladenineaugments OEL-induced apoptotic cell death. The inductionof autophagy and apoptosis by OEL links to NF-jB activationand the generation of reactive oxygen species (ROS). Interruption of NF-jB activation by specific inhibitor promotesapoptosis, but decreases autophagy. ROS antioxidants(N-acetylcysteine) attenuated both OEL-inducedautophagy and apoptosis. Further experiments confirmedthat OEL-induced activation of ROS was increased by NFjBinhibitor whereas NF-jB activation was not affected by ROS inhibition. These findings suggest that OEL-elicitedautophagic response plays a protective role that impedescell death, and inhibition of autophagy could be anadjunctive strategy for enhancing the chemotherapeuticeffect of OEL as an antitumor agent.

Numerical calculation method for response of friction pendulum system when XY shear keys are sheared asynchronously

Biao Wei,Yunji Fu,Lizhong Jiang,Shanshan Li 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.81 No.5

When the friction pendulum system and shear keys work together to resist the ground motion ,which inclined inputs (non 45°) to the bridge structure, the shear keys in XY direction will be sheared asynchronously, endowed the friction pendulum system with a violent curvilinear motion on the sliding surface during earthquakes. In view of this situation, firstly, this paper abandons the equivalent linearization model of friction and constructs a Spring-Coulomb friction plane isolation system with XY shear keys, and then makes a detailed mechanical analysis of the movement process of friction pendulum system, next, this paper establishes the mathematical model of structural time history response calculation by using the step-by-step integration method, finally, it compiles the corresponding computer program to realize the numerical calculation. The results show that the calculation method in this paper takes advantage of the characteristic that the friction force is always , and creatively uses the "circle making method" to express the change process of the friction force and resultant force of the friction pendulum system in any calculation time step, which can effectively solve the temporal nonlinear action of the plane friction; Compared with the response obtained by the calculation method in this paper, the peak values of acceleration response and displacement response calculated by the unidirectional calculation model, which used in the traditional research of the friction pendulum system, are smaller, so the unidirectional calculation model is not safe.

Insulator Defects Detection for Aerial Photography of the Power Grid Using You Only Look Once Algorithm

Wang Shanshan,Zou Xinyi,Zhu Wei,Zeng Liang 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.4

The safe operation of the power grid system depends partly on regular inspections of transmission lines, in which the insulator is one of the most important inspections objects. The manual inspection of transmission lines is a chaotic process that is both time and cost-consuming since it involves an accurate manual inspection by an expert. For insulator defect detection, an improved YOLOv4 algorithm is proposed. First, a new data augmentation method is proposed to solve the problem of insufficient sample size. Then, the size of the anchor boxes is redesigned base on the K-means algorithm to further improve the detection precision. Finally, an insulator defects detection network is constructed based on YOLOv4. Experimental results show that the detection precision of the improved network is 37.2% higher after data enhancement and anchor boxes redesign. In addition, the detection method proposed in this paper is superior to other popularity detection algorithms, including the single shot detector, region-convolutional neural networks (Faster-RCNN) and released version of you only look once (YOLO). The value of mean average precision is 99.08% and frame per second is 56. The robustness test results demonstrate that our proposed algorithm performs well under different light intensities and complex environmental backgrounds, and can accurately detect all targets, which is significantly better than other comparative algorithms. In terms of detection accuracy, test speed and robustness, our proposed algorithm meets the requirements of industrial field applications of insulator defect detection.