http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A New Triterpene and an Antiarrhythmic Liriodendrin from Pittosporum brevicalyx
Chun Feng,Bo-Gang Li,Xiao-Ping Gao,Hua-Yi Qi,Guo-Lin Zhang 대한약학회 2010 Archives of Pharmacal Research Vol.33 No.12
A new triterpene, 21-O-senecioyl-R1-barrigenol (1) and 13 known compounds were isolated from the ethanol extracts of the leaves and bark of Pittosporum brevicalyx (Oliv.) Gagnep. Their structures were elucidated based on spectral data. The antiarrhythmic action of one furofuran lignan, liriodendrin (2), was tested on a model of CaCl2-induced arrhythmia and compared with the effect of verapamil. The prophylactic administration of liriodendrin (2) was effective in prolonging latency of arrhythmia and reducing the occurrence of ventricular fibrillation from 75% to 25%. The overall mortality rate was significantly reduced by the prophylactic administration of liriodendrin from 87.5% to 25%. The antiarrhythmic effect of liriodendrin (5.0 mg/kg) was similar to that of verapamil (1.05 mg/kg). Thus, liriodendrin may be a potent suppressor of CaCl2-induced arrhythmias.
Damage identification using chaotic excitation
Chunfeng Wan,Tadanobu Sato,Zhishen Wu,Jian Zhang 국제구조공학회 2013 Smart Structures and Systems, An International Jou Vol.11 No.1
Vibration-based damage detection methods are popular for structural health monitoring. However, they can only detect fairly large damages. Usually impact pulse, ambient vibrations and sine-wave forces are applied as the excitations. In this paper, we propose the method to use the chaotic excitation to vibrate structures. The attractors built from the output responses are used for the minor damage detection. After the damage is detected, it is further quantified using the Kalman Filter. Simulations are conducted. A 5-story building is subjected to chaotic excitation. The structural responses and related attractors are analyzed. The results show that the attractor distances increase monotonously with the increase of the damage degree. Therefore, damages, including minor damages, can be effectively detected using the proposed approach. With the Kalman Filter, damage which has the stiffness decrease of about 5% or lower can be quantified. The proposed approach will be helpful for detecting and evaluating minor damages at the early stage.
Chunfeng Wan,Akira Mita 국제구조공학회 2010 Smart Structures and Systems, An International Jou Vol.6 No.4
This paper proposes a method for early warning of hazard for pipelines. Many pipelines transport dangerous contents so that any damage incurred might lead to catastrophic consequences. However, most of these damages are usually a result of surrounding third-party activities, mainly the constructions. In order to prevent accidents and disasters, detection of potential hazards from third-party activities is indispensable. This paper focuses on recognizing the running of construction machines because they indicate the activity of the constructions. Acoustic information is applied for the recognition and a novel pipeline monitoring approach is proposed. Principal Component Analysis (PCA) is applied. The obtained Eigenvalues are regarded as the special signature and thus used for building feature vectors. One-class Support Vector Machine (SVM) is used for the classifier. The denoising ability of PCA can make it robust to noise interference, while the powerful classifying ability of SVM can provide good recognition results. Some related issues such as standardization are also studied and discussed. On-site experiments are conducted and results prove the effectiveness of the proposed early warning method. Thus the possible hazards can be prevented and the integrity of pipelines can be ensured.
Chunfeng Wan,Guangcai Zhang,Liyu Xie,Songtao Xue 국제구조공학회 2023 Smart Structures and Systems, An International Jou Vol.31 No.3
The absence of excitation measurements may pose a big challenge in the application of structural damage identification owing to the fact that substantial effort is needed to reconstruct or identify unknown input force. To address this issue, in this paper, an iterative strategy, a synergy of Tikhonov regularization method for force identification and modified Jaya algorithm (M-Jaya) for stiffness parameter identification, is developed for damage identification with partial output-only responses. On the one hand, the probabilistic clustering learning technique and nonlinear updating equation are introduced to improve the performance of standard Jaya algorithm. On the other hand, to deal with the difficulty of selection the appropriate regularization parameters in traditional Tikhonov regularization, an improved L-curve method based on B-spline interpolation function is presented. The applicability and effectiveness of the iterative strategy for simultaneous identification of structural damages and unknown input excitation is validated by numerical simulation on a 21-bar truss structure subjected to ambient excitation under noise free and contaminated measurements cases, as well as a series of experimental tests on a five-floor steel frame structure excited by sinusoidal force. The results from these numerical and experimental studies demonstrate that the proposed identification strategy can accurately and effectively identify damage locations and extents without the requirement of force measurements. The proposed M-Jaya algorithm provides more satisfactory performance than genetic algorithm, Gaussian bare-bones artificial bee colony and Jaya algorithm.
An Improved Differential Evolution Algorithm for Solving High Dimensional Optimization Problem
Chunfeng Song,Yuanbin Hou 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.10
In order to improve the weak situation of the global search ability, the stability and time consuming of optimization of differential evolution(DE) algorithm in solving high dimensional optimization problem, an improved differential evolution algorithm with multi- population and multi-strategy(MPMSIDE) is proposed to solve high dimensional optimization problem. Firstly, the different DE mutation strategies are studied. Then the MPMSIDE algorithm divides the population into several sub-populations, which evolve independently and communicate with each other at regular intervals by using different DE strategies, in order to save the computation time. And the improved mutation strategy and local optimization strategy are introduced to raise and balance the global searching ability and local searching ability, and improve the optimization efficiency. The selfadaptive update strategy is used to adjust the scaling factor and crossover factor for making the parameter sensitivity of DE algorithm and improving the stability and robustness. Finally, the proposed MPMSIDE algorithm is applied to standard test function optimization for verifying the effectiveness. The experimental results show that the proposed MPMSIDE algorithm has a relatively better optimization performance for solving complex optimization problem, and takes on remarkable optimizing ability, higher searching accuracy and faster convergence speed.
Chunfeng Wang,Jun Yang,Guilin Liu,Hong Gao,Meiling Chen 한양대학교 세라믹연구소 2022 Journal of Ceramic Processing Research Vol.23 No.4
This study aims to reveal the changes in the microstructure of hypoeutectic gray cast iron under the addition of compositesilicon carbide powder of different mass fractions, and to explore how modified silicon carbide (SiC) particles of different sizesand contents improve the mechanical properties of hypoeutectic gray cast iron. The results showed that the modified SiCparticles increased the nucleation, the undercooling and microstructure of hypoeutectic gray cast iron, and the tensile strengthof the iron at room temperature was increased by 18,28%. The present work solves the problem that traditional SiC ceramicparticles are prone to agglomeration in molten metal, analyzes its action mechanism, and can expand the application of SiCceramic particles to strengthening metal properties of casting materials.
Design of Abnormal Data Analysis and Processing System Based on RFID Supply Chain
Chunfeng Wang,Shuiming Zhong,Jin Wang 보안공학연구지원센터 2014 International Journal of Multimedia and Ubiquitous Vol.9 No.11
With the deep application of RFID, the deployment of the RFID system is gradually to have the large-scale, networked, distributed development trend. The previous abnormal data analysis and processing way can not meet with the need of data processing. According to the survey of international famous consulting company (Gartner) for the "information overload", results show that more than 90% of the enterprises think the enterprise competitiveness is closely related to its information capacity. In order to obtain the useful information, we must analyze, process the data, and exclude "exception" data. So, it is very important to realize the detection of abnormal data. This paper presents the RFID supply an abnormal data analysis and processing system of RFID supply chain based on distance, rules and middleware technology .This system is divided into three levels: data processing layer, anomaly analysis lay and graphical display layer. Finally, through the performance analysis of the system, the effectiveness of the system has been verified.