http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Second order effects of external prestress on frequencies of simply supported beam by energy method
Fang, De-Ping Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.52 No.4
Based on the energy method considering the second order effects, the natural frequencies of externally prestressed simply supported beam and the compression softening effect of external prestress force were analyzed. It is concluded that the compression softening effect depends on the loss of external tendon eccentricity. As the number of deviators increases from zero to a large number, the compression softening effect of external prestress force decreases from the effect of axial compression to almost zero, which is consistent with the conclusion mathematically rigorously proven. The frequencies calculated by the energy method conform well to the frequencies by FEM which can simulate the frictionless slide between the external tendon and deviator, the accuracy of the energy method is validated. The calculation results show that the compression softening effect of external prestress force is negligible for the beam with 2 or more deviators due to slight loss of external tendon eccentricity. As the eccentricity and area of tendon increase, the first natural frequency of the simply supported beams noticeably increases, however the effect of the external tendon on other frequencies is negligible.
Second order effects of external prestress on frequencies of simply supported beam by energy method
De-Ping Fang 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.52 No.4
Based on the energy method considering the second order effects, the natural frequencies of externally prestressed simply supported beam and the compression softening effect of external prestress force were analyzed. It is concluded that the compression softening effect depends on the loss of external tendon eccentricity. As the number of deviators increases from zero to a large number, the compression softening effect of external prestress force decreases from the effect of axial compression to almost zero, which is consistent with the conclusion mathematically rigorously proven. The frequencies calculated by the energy method conform well to the frequencies by FEM which can simulate the frictionless slide between the external tendon and deviator, the accuracy of the energy method is validated. The calculation results show that the compression softening effect of external prestress force is negligible for the beam with 2 or more deviators due to slight loss of external tendon eccentricity. As the eccentricity and area of tendon increase, the first natural frequency of the simply supported beams noticeably increases, however the effect of the external tendon on other frequencies is negligible.
Fang Guo,Zong-De Fang 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.3
To study the actual changing rule of the meshing-in impact considering the measured pitch error and the effect on the dynamic characteristics of a gear system, this paper presents a new algorithm to calculate the meshing-in impact considering the measured pitch error. Based on the tooth contact analysis and loaded tooth contact analysis considering the measured pitch error, the algorithm can determine the exact original position where each mating tooth pair comes into contact in the process of gear transmission. Furthermore, we consider the meshing-in impact as dynamic excitation and simulate the dynamic response of the gear system with or without this excitation. The simulation result is expressed in time and frequency domains, phase plane plots and Poincaré maps. By using the wavelet packet transformation, the impact feature is extracted from the vibration response of the gear system.
Jian, Fang-Fang,Zhao, Pu-Su,Wang, Huan-Xiang,Lu, Lu-De Korean Chemical Society 2004 Bulletin of the Korean Chemical Society Vol.25 No.5
The tetranuclear copper(II) cluster compound $[Cu_4OCl_6(C_{14}H_{12}N_2)_4]$ has been synthesized by hydrothermal reaction and studied by X-ray diffraction. The four copper(II) atoms locate four capsheaves of a tetrahedral skeletal structure and a oxygen atom as interstitial atom occupies the center position of the same tetrahedron, and each edge of the Cu-Cu tetrahedron is bridged by one ${\mu}_2$-Cl anion. The copper atom possesses slightly distorted trigonal bipyramidal geometry with three ${\mu}_2$-Cl atoms in equatorial position and the interstitial O atom and one N atom from 3-benzyl-benzimidazole ligand occupying axial position. The Cu-Cu distances are in the range of 3.0986-3.1162 ${\AA}$. The EPR spectrum suggested that the copper(II) ground state $d_{x2-y2}$ and the coordination geometry was trigonal bipyramidal.
Study on Corner Reflectors Identification in Highway Deformation Monitoring
Xue Min Xing,De Bao Wen,Fang Bin Zhou 보안공학연구지원센터 2014 International Journal of Multimedia and Ubiquitous Vol.9 No.12
CRInSAR is a newly developed technique to monitor ground deformation. In CRInSAR algorithm, the identification of Corner Reflectors in SAR images is necessary. Due to the uncertainty of traditional identification method, a new method based on the intensity and correlation coefficient of each CR candidates in SAR images is presented. The method has been successfully used to determine the locations of 11 CRs installed along a highway in six SAR images over the study area. The results show that the identification accuracy of the new method is about 1 pixel. It is effective and reliable especially in the area with lots of lightspots around the CR points. The method proposed can play important role in the highway deformation monitoring within CRInSAR algorithm.
De-Jun Cheng,Jie Zhang,Zhong-Tai Hu,Sheng-Hao Xu,Xi-Feng Fang 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.10
This paper aims to propose a digital twin-driven (DTD) approach that consists of the machining data (MD) in twin data (TD), design of MD acquisition methodology, construction of intelligent algorithm, real-virtual data interaction analysis and fusion technology, which improvs the predictability and management of on-line quality control of marine diesel engine (MDE) critical parts. Firstly, this paper introduces the theoretical framework of DTD on-line quality control in machining process. Secondly, we construct the process of DTD on-line quality control and introduce the digital twin model of on-line quality control based on TD-driven; the operation of data-driven quality on-line control based on digital twin including description and modeling of MD; acquisition of MD based on digital twin; TD-driven on-line tool life prediction and data fusion on-line machining parameters optimization methods. Finally, a case study is applied to validate the accuracy and availability of the DTD approach. The proposed approach provides a new way for the on-line quality control of MDE critical parts in machining process.
Two New Metabolites with Cytotoxicities from Deep-Sea Fungus, Aspergillus sydowi YH11-2
De-Hai Li,Sheng-Xin Cai,Li Tian,Zhen-Jian Lin,Tian-Jiao Zhu,Yu-Chun Fang,Pei-Pei Liu,Qian-Qun Gu,Wei-Ming Zhu 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.9
Two new compounds, 2, 3, 5-trimethyl-6-(3-oxobutan-2-yl)-4H-pyran-4-one (1) and (2R)-2, 3- dihydro-7-hydroxy-6, 8-dimethyl-2-[(E)-prop-1-enyl] chromen-4-one (2), together with six known compounds (3-8), were isolated from a deep-sea fungus, identified as Aspergillus sydowi, by a bioassay-guided method. Their structures were elucidated by spectroscopic methods and the cytotoxicities were evaluated by SRB method.
Evaluation of barrier plants for the cultural control of tomato yellow leaf curl disease
Fang-Yu Hu,De-Fen Mou,Chi-Wei Tsai 한국응용곤충학회 2020 Journal of Asia-Pacific Entomology Vol.23 No.1
Barrier cropping plays an essential role in controlling insect pests and insect-transmitted diseases in cultural control. It has been proven efficient in suppressing the spread of nonpersistently transmitted viruses. For suppressing the spread of persistently transmitted viruses, barrier cropping is not considered an effective control strategy because barrier plants cannot act as a virus sink to purge the virus in the vector. However, few successful cases of barrier cropping suppressing the spread of persistently transmitted viruses have been reported. The objectives of the present study were to screen candidates (cucumber, okra, Chinese kale, soybean, and corn) for potential barrier plants to control tomato yellow leaf curl Thailand virus (TYLCTHV) and examine whether prefeeding on these plants can reduce the virus titer in its vector, Bemisia tabaci, thus reducing TYLCTHV transmission. The results revealed that nonviruliferous whiteflies preferred cucumber and okra to tomato, whereas viruliferous whiteflies preferred cucumber to tomato. Although prefeeding on cucumber, okra, and Chinese kale did not reduce the titer of TYLCTHV in viruliferous whiteflies, the vector transmission rate decreased after the whiteflies fed on Chinese kale. It implies that planting Chinese kale as a barrier plant for tomato cultivation may reduce the incidence of TYLCTHV. In addition, the preference to cucumber plants may reduce the incidence of whiteflies acquiring TYLCTHV from virus-infected tomato plants and of viruliferous whiteflies inoculating the virus into healthy tomato plants, thereby reducing the disease incidence. Further field trials of barrier cropping using the candidate plants are warranted.