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Guochao Zheng,Wei Hu,Yuanjia Liu,Qin Luo,Liping Tan,Guoqing Li 대한기생충학열대의학회 2015 The Korean Journal of Parasitology Vol.53 No.1
The objective of this study was to genetically characterize isolates of Giardia duodenalis and to determine if zoonotic potential of G. duodenalis could be found in stray cats from urban and suburban environments in Guangzhou, China. Among 102 fresh fecal samples of stray cats, 30 samples were collected in Baiyun district (urban) and 72 in Conghua district (suburban). G. duodenalis specimens were examined using light microscopy, then the positive specimens were subjected to PCR amplification and subsequent sequencing at 4 loci such as glutamate dehydrogenase (gdh), triose phosphate isomerase (tpi), β-giardin (bg), and small subunit ribosomal RNA (18S rRNA) genes. The phylogenetic trees were constructed using obtained sequences by MEGA5.2 software. Results show that 9.8% (10/102) feline fecal samples were found to be positive by microscopy, 10% (3/30) in Baiyun district and 9.7% (7/72) in Conghua district. Among the 10 positive samples, 9 were single infection (8 isolates, assemblage A; 1 isolate, assemblage F) and 1 sample was mixed infection with assemblages A and C. Based on tpi, gdh, and bg genes, all sequences of assemblage A showed complete homology with AI except for 1 isolate (CHC83). These findings not only confirmed the occurrence of G. duodenalis in stray cats, but also showed that zoonotic assemblage A was found for the first time in stray cats living in urban and suburban environments in China.
Effect of grinding depth on fatigue fracture behaviors of 40Cr steel
Jianzhi Chen,Guochao Li,Ning Li,Xiaoyan Guan,Yan Wang,Zhen Xu,Xiaoxiang Bai,Honggen Zhou 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4
40Cr steel specimens were ground with different grinding depth (a p ) varied from 0 μm to 35 μm, and the rotary bending fatigue behaviors of ground specimens were investigated. Fatigue results show that the fatigue life of ground specimens exhibits an increasing first and then decreasing tendency with the increment of a p , the specimen with a p of 15 μm exhibits the highest fatigue life, and the effect of a p on fatigue damage behaviors of ground specimens were analyzed from aspects of surface roughness, work hardening and compressive residual stress. Multiple crack initiation of fatigue fractured specimens was observed, the number of crack initiation sites tends to increase first and then decrease with increasing a p . The relationship model between the fatigue striation width and the a p was established, and the prediction deviation of the model is ~2.08 %. It is expected that the model may provide new clues for optimizing the grinding process of mechanical parts.
Dynamic and static structural displacement measurement using backscattering DC coupled radar
Shanyue Guan,Jennifer A. Rice,Changzhi Li,Yiran Li,Guochao Wang 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.16 No.3
Vibration-based monitoring is one approach used to perform structural condition assessment. By measuring structural response, such as displacement, dynamic characteristics of a structure may be estimated. Often, the primary dynamic responses in civil structures are below 5 Hz, making accurate low frequency measurement critical for successful dynamic characterization. In addition, static deflection measurements are useful for structural capacity and load rating assessments. This paper presents a DC coupled continuous wave radar to accurately detect both dynamic and static displacement. This low-cost radar sensor provides displacement measurements within a compact, wireless unit appropriate for a range of structural monitoring applications. The hardware components and operating mechanism of the radar are introduced and a series of laboratory experiments are presented to assess the performance characteristics of the radar. The laboratory and field experiments investigate the effect of factors such as target distance, motion amplitude, and motion frequency on the radar’s measurement accuracy. The results demonstrate that the radar is capable of both static and dynamic displacement measurements with sub-millimeter accuracy, making it a promising technology for structural health monitoring.
Yali Ma,Jiayong Wei,Cancan Li,Chen Liang,Guochao Liu 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.7
Aiming at the problem that the multi-objective evaluation of performance and the weighting coefficients of indexes is difficult to find, a fuzzy comprehensive performance evaluation method of rolling linear guide (RLG) is proposed. Considering the static and dynamic indexes, a structure model containing nine weighting coefficients was constructed. The performance evaluation function was established by the compromise programming method and the average power method, while weighting coefficients were determined by the improved analytic hierarchy process (I-AHP); the mathematical model was obtained to evaluate the RLG in a certain application. The evaluation results show that the confidence of the static, dynamic and comprehensive performance of the RLG is 59.21 %, 81.97 %, and 63.34 %, respectively. The feasibility of the method was verified by numerical simulation. This method indicates the pros and cons of the performance of the RLG and also indicates the direction for its optimized design.
Guizhong Tian,Zhengyu Ma,Donghao Zhao,Honggen Zhou,Xuwen Jing,Zhancheng Xie,Guochao Li 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6
The residual stresses (RS) generated during the thermal processing processes such as casting and heat treatment is one of the fundamental causes of irreversible deformation of diesel engine bodies (DEBs). However, previous studies only focused on the RS generated from casting or the effect of annealing heat treatment on the RS in castings unilaterally, and the analytical results were far from the actual conditions. Therefore, this paper proposes a comprehensive research method to consider the whole dynamic evolution of the casting from the RS generated by casting to the stress relief by heat treatment. Numerical simulation of DEBs casting process is carried out by PROCAST, and the results of casting RS obtained from the simulation are imported into ABAQUS, and then numerical simulation of annealing heat treatment is carried out for the DEB casting model with casting RS, so as to realize the analysis of dynamic evolution of RS from casting to heat treatment.