The Study of Variational Feed Rate in 4-Axis Machining of Blades

Qing-Chun Tang,ShaoHui Yin,Jun-Xiao Geng,Hu Luo,Yue-Ping Chen 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.10

As a core part of aerospace, space, and steam turbine plants, blades are generally machined via 5-axis linkage processing to satisfy the high precision requirements of the rigorous surface. To save costs in blade machining, many small- and medium-sized enterprises often combine standard 3-axis computer numeric control machines with the automatic indexing turntable. The traditional 4-axis machining method adopts a constant feed rate, which causes overcutting near the leading and trailing edges of the blade because of the rapid changes in tool orientation. To solve this problem, we propose a speed optimization method that utilizes variational speed to ensure that the decomposition velocity and acceleration of each axis do not exceed the allowable values. First, we guarantee the correct tool lead angle. Second, a corrected speed model is established to obtain the component speed of each axis and to determine the constraint conditions of maximum and accelerated speed. Third, a 4-axis post processor for blade processing is developed using Java advanced language combined with the optimization algorithm. The cutting experiment reveals that our proposed speed optimization method effectively controls the precision of the surface profile and overcomes the overcut phenomenon that often occurs in traditional 4-axis machining.

Automatic Detection and Classification of Rib Fractures on Thoracic CT Using Convolutional Neural Network: Accuracy and Feasibility

Zhou Qing-Qing,Wang Jiashuo,Tang Wen,Hu Zhang-Chun,Xia Zi-Yi,Xue-Song Li,Zhang Rongguo,Yin Xindao,Zhang Bing,Zhang Hong 대한영상의학회 2020 Korean Journal of Radiology Vol.21 No.7

Objective: To evaluate the performance of a convolutional neural network (CNN) model that can automatically detect and classify rib fractures, and output structured reports from computed tomography (CT) images. Materials and Methods: This study included 1079 patients (median age, 55 years; men, 718) from three hospitals, between January 2011 and January 2019, who were divided into a monocentric training set (n = 876; median age, 55 years; men, 582), five multicenter/multiparameter validation sets (n = 173; median age, 59 years; men, 118) with different slice thicknesses and image pixels, and a normal control set (n = 30; median age, 53 years; men, 18). Three classifications (fresh, healing, and old fracture) combined with fracture location (corresponding CT layers) were detected automatically and delivered in a structured report. Precision, recall, and F1-score were selected as metrics to measure the optimum CNN model. Detection/diagnosis time, precision, and sensitivity were employed to compare the diagnostic efficiency of the structured report and that of experienced radiologists. Results: A total of 25054 annotations (fresh fracture, 10089; healing fracture, 10922; old fracture, 4043) were labelled for training (18584) and validation (6470). The detection efficiency was higher for fresh fractures and healing fractures than for old fractures (F1-scores, 0.849, 0.856, 0.770, respectively, p = 0.023 for each), and the robustness of the model was good in the five multicenter/multiparameter validation sets (all mean F1-scores > 0.8 except validation set 5 [512 x 512 pixels; F1-score = 0.757]). The precision of the five radiologists improved from 80.3% to 91.1%, and the sensitivity increased from 62.4% to 86.3% with artificial intelligence-assisted diagnosis. On average, the diagnosis time of the radiologists was reduced by 73.9 seconds. Conclusion: Our CNN model for automatic rib fracture detection could assist radiologists in improving diagnostic efficiency, reducing diagnosis time and radiologists’ workload.

Simulation of the Structural Parameters of Anti-resonant Hollow-core Photonic Crystal Fibers

Qing Liu,Yujun Feng,Yinhong Sun,Zhe Chang,Yanshan Wang,Wanjing Peng,Yi Ma,Chun Tang 한국광학회 2022 Current Optics and Photonics Vol.6 No.2

Anti-resonant hollow-core photonic crystal fiber (AR-HCF) has unique advantages, such as low nonlinearity and high damage threshold, which make it a promising candidate for high-power laser delivery at distances of tens of meters. However, due to the special structure, optical properties such as modefield profile and bending loss of hollow-core fibers are different from those of solid-core fibers. These differences have limited the widespread use of AR-HCF in practice. In this paper we conduct numerical analysis of AR-HCFs with different structural parameters, to analyze their influences on an AR-HCF’soptical properties. The simulation results show that with a 23-μm air-core diameter, the fundamentalmode profile of an AR-HCF can well match that of the widely used Nufern’s 20/400 fiber, for nearlysingle-mode power delivery applications. Moreover, with the ratio of cladding capillary diameter to aircore diameter ranging from 0.6 to 0.7, the AR-HCF shows excellent optical characteristics, including low bending sensitivity while maintaining single-mode transmission at the same time. We believe these results lay the foundation for the application of AR-HCFs in the power delivery of high power fiber laser systems.

Landscape structures of the Central Yangtze region, China

Tang, Zhi Yao,Fang, Jing Yun,Zhao, Shu Qing,Rao, Sheng,Lei, Guang Chun,Cui, Hai Ting 대한원격탐사학회 2000 International Symposium on Remote Sensing Vol.16 No.1

As habitats for many migratory birds, the plain regions of Central Yangtze plays an important role in biodiversity conservation, especially in conservation for birds and fishes. In this study, the landscape structures of the plain regions of the Central Yangtze were analyzed by using remote sensing image data (Landsat TM) and technique of geographical information system (GIS). The landscape component was divided into eight types, broad-leaved forest, shrub, meadow, water body, cropland, urban and bared land. The main results are summarized as follow: (1) Broad-leaved forest is almost made of small patches, while water body and cropland mainly made of large-area patches, suggesting that water body and cropland are the dominant components for landscape structures. (2) Shrub and meadow are highly fragmented, compared to cropland and water body. Water body, meadow and shrub are randomly distributed, whilst bared land and urban occur aggregately. (3) Places with high fragmentation index show a low dominance index value and unapparent dominant components, while the areas with low fragmentation indices, such as Dongting Lake, Poyang Lake and Jianghan Plain, indicate a high dominance index value in which the dominant components were distinct.

Screening and Cloning of RAPD Markers from the W Chromosome of Silkworm, Bombyx mori L.

( Chun Xia Zhang ),( Qin Yao ),( Qing Gang Xu ),( Xu Dong Tang ),( Ke Ping Chen ) 한국잠사학회 2007 International Journal of Industrial Entomology Vol.8 No.2

Silkworms sex determination drew high attention from researchers. Sex chromosomes on the silkworm are of ZW type for females and ZZ type for males. Chromosome W plays an important role in sex determination. Although several molecular linkage maps have been constructed for silkworm, very few markers are discovered on the W chromosome. In order to look for molecular markers and to further locate the Fem gene on chromosome W, we used genomic DNA from both female and male larvae of a silkworm strain named 937 as PCR templates for RAPD amplification with 200 arbitrary 10-mer primers. The amplification results showed three female-specific bands, namely OPG-07(496), OPC-15(1,660) and OPE-18(1,279). Further verification, however, revealed no band from OPG-07 and OPC-15 in either sex in the strain 798, but OPE-18 provided female-specific band in the strains Suluan7 and C108, and absent in both males and strain 798. This indicates that the bands from OPG-07(496) and OPC-15(1,660) are probably female-specific in strain 937, and the band from OPE-18 was probably amplified from a common segment shared by most strains. The genomic DNAs from OPG-07 and OPC-15 were cloned and sequenced. Sequence analysis showed that the DNAs from OPG-07 and OPC-15 have high identities with the retrotransposable elements, and DNA from OPC-15 contains a portion of sequence which probably encodes an eukaryotic translation initiation factor 4E binding protein (eIF4EBP).

Lentivirus-mediated Silencing of Rhomboid Domain Containing 1 Suppresses Tumor Growth and Induces Apoptosis in Hepatoma HepG2 Cells

Liu, Xue-Ni,Tang, Zheng-Hao,Zhang, Yi,Pan, Qing-Chun,Chen, Xiao-Hua,Yu, Yong-Sheng,Zang, Guo-Qing Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.1

Rhomboids were identified as the first intramembrane serine proteases about 10 years ago. Since then, the study of the rhomboid protease family has blossomed. Rhomboid domain containing 1 (RHBDD1), highly-expressed in human testis, contains a rhomboid domain with unknown function. In the present study, we tested the hypothesis that RHBDD1 was associated with proliferation and apoptosis in hepatocellular carcinoma using recombinant lentivirus-mediated silencing of RHBDD1 in HepG2 cells. Our results showed that down-regulation of RHBDD1 mRNA levels markedly suppressed proliferation and colony formation capacity of HepG2 human hepatoma cancer cells in vitro, and induced cell cycle arrest. We also found that RHBDD1 silencing could obviously trigger HepG2 cell apoptosis. In summary, it was demonstrated that RHBDD1 might be a positive regulator for proliferative and apoptotic characteristics of hepatocellular carcinoma.