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CONSTRAINED INTERPOLATION USING RATONAL CUBIC SPLINE WITH LINEAR DENOMINATORS
Duan, Qi,Xu, Gongxue,Liu, Aikui,Wang, Xuefu,Chen, Fuhua 한국전산응용수학회 1999 Journal of applied mathematics & informatics Vol.6 No.1
In this paper a rational cubic interpolant spline with linear denominator has been constructed and it is used to constrain interpolation curves to be bounded in the given region. Necessary and sufficient conditions for the interpolant to satisfy the constraint have been developed. The existence conditions are computationally efficient and easy to apply. Finally the approximation properties have been studied.
CONVEXITY CONTROL AND APPROXIMATION PROPERTIES OF INTERPOLATING CURVES
Qi, Duan,Chen, Tzer-Shyong,Djidjeli, K.,Price, W.G.,Twizell, E.H. 한국전산응용수학회 2000 Journal of applied mathematics & informatics Vol.7 No.2
A constrained rational cubic spline with linear denominator was constructed in [1]. In the present paper, the sufficient condition for convex interpolation and some properties in error estimation are given.
Qi Duan,Tingting Wang,Na Zhang,Vern Perera,Xue Liang,Iruni Roshanie Abeysekera,Xiaomei Yao 대한내분비학회 2016 Endocrinology and metabolism Vol.31 No.1
Background: Increased oxidative stress has been suggested as one of the underlying mechanisms in iodide excess-induced thy roid disease. Metallothioneins (MTs) are regarded as scavengers of reactive oxygen species (ROS) in oxidative stress. Our aim is to investigate the effects of propylthiouracil (PTU), a thyroid peroxidase inhibitor, perchlorate (KClO4), a competitive inhibitor of iodide transport, and thyroid stimulating hormone (TSH) on mitochondrial superoxide production instigated by high concentra tions of iodide in the thyroids of MT-I/II knockout (MT-I/II KO) mice. Methods: Eight-week-old 129S7/SvEvBrd-Mt1 tm1Bri Mt2tm1Bri/J (MT-I/II KO) mice and background-matched wild type (WT) mice were used. Results: By using a mitochondrial superoxide indicator (MitoSOX Red), lactate dehydrogenase (LDH) release, and methyl thia zolyl tetrazolium (MTT) assay, we demonstrated that the decreased relative viability and increased LDH release and mitochon drial superoxide production induced by potassium iodide (100 μM) can be relieved by 300 μM PTU, 30 μM KClO4, or 10 U/L TSH in the thyroid cell suspensions of both MT-I/II KO and WT mice (P<0.05). Compared to the WT mice, a significant de crease in the relative viability along with a significant increase in LDH release and mitochondrial superoxide production were de tected in MT-I/II KO mice (P<0.05). Conclusion: We concluded that PTU, KClO4, or TSH relieved the mitochondrial oxidative stress induced by high concentrations of iodide in the thyroids of both MT-I/II KO and WT mice. MT-I/II showed antioxidant effects against high concentrations of io dide-induced mitochondrial superoxide production in the thyroid.
Engineering of a Bacillus subtilis Strain Deficient in Cellulase: Application in Degumming of Ramie
Qi Yang,Shengwen Duan,Lifeng Cheng,Xiangyuan Feng,Ke Zheng,Chunliang Xie,Zhiyuan Liu,Yuande Peng 한국섬유공학회 2019 Fibers and polymers Vol.20 No.1
Degumming is the most important step before ramie fibers are used in textile industry. Conventional chemical degumming technology with alkaline treatment at high temperature causes critical problems in environment. In addition to multiple degumming enzymes (e.g. pectinases and xylanases), Bacillus subtilis strain 168 can also produce cellulase which brings irreversible damage to ramie fibers. In this study, a strain deficient in cellulase was constructed by insertional inactivation of gene eglS to make it suitable for microbial degumming. Results showed that the cellulase activity was not detected in strain ΔeglS, after 25 h of incubation with strain ΔeglS, the weight loss of the ramie fibers was 20.20 %. Though the residual gum content of ramie fibers obtained in microbial degumming process was 19.67 %, microbial intervention followed by diluted alkaline solution treatment showed lower residual gum content (2.73 %) than chemical degumming (2.96 %). The single fiber breaking strength value of ramie fibers from bio-chemical degumming process reached 27.19 cN, which was the highest of three samples. Moreover, bio-chemical degumming process resulted in a 75 % decrease of alkali dosage as compared with chemical degumming process. This study provides a suggestion to genetically modify wild-type strain in order to protect ramie fibers from cellulase damage, and indicates a sustainable alternative for the traditional chemical degumming in the textile industry.
Qi Meng,Jianguo Duan,Ying-Jie Zhang,Peng Dong 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-
In this study, a novel efficient and environmentally friendly recycling process is developed to recoverspent LiMn2O4 powder as raw materials for high-performance LiMnPO4/C nanocomposites. The processcomprises a mechanochemical liquid-phase activation of the precursor mixture followed by a single-stepsolid-state heat treatment. The results indicate that the recovered LiMnPO4/C nano-composite has apromising electrochemical performance with discharge capacities of 148.5, 136.1, and 116.5 mA h g 1 at0.05, 0.2, and 1C rate, respectively, in the voltage range of 2.5–4.5 V. A perfect cyclic performance is alsodisplayed with a capacity retention of 98% after 100 cycles at 1C rate.
CNN-based damage identification method of tied-arch bridge using spatial-spectral information
Yuanfeng Duan,Qianyi Chen,Hongmei Zhang,Chung Bang Yun,Sikai Wu,Qi Zhu 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.23 No.5
In the structural health monitoring field, damage detection has been commonly carried out based on the structural model and the engineering features related to the model. However, the extracted features are often subjected to various errors, which makes the pattern recognition for damage detection still challenging. In this study, an automated damage identification method is presented for hanger cables in a tied-arch bridge using a convolutional neural network (CNN). Raw measurement data for Fourier amplitude spectra (FAS) of acceleration responses are used without a complex data pre-processing for modal identification. A CNN is a kind of deep neural network that typically consists of convolution, pooling, and fully-connected layers. A numerical simulation study was performed for multiple damage detection in the hangers using ambient wind vibration data on the bridge deck. The results show that the current CNN using FAS data performs better under various damage states than the CNN using time-history data and the traditional neural network using FAS. Robustness of the present CNN has been proven under various observational noise levels and wind speeds.
Yuanfeng Duan,Qi Zhu,Hongmei Zhang,Wei Wei,Chung Bang Yun 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.28 No.6
High-voltage isolating switches play a paramount role in ensuring the safety of power supply systems. However, their exposure to outdoor environmental conditions may cause serious physical defects, which may result in great risk to power supply systems and society. Image processing-based methods have been used for anomaly detection. However, their accuracy is affected by numerous uncertainties due to manually extracted features, which makes the anomaly detection of isolating switches still challenging. In this paper, a vision-based anomaly detection method for isolating switches, which uses the rotational angle of the switch system for more accurate and direct anomaly detection with the help of deep learning (DL) and image processing methods (Single Shot Multibox Detector (SSD), improved frame differencing method, and Hough transform), is proposed. The SSD is a deep learning method for object classification and localization. In addition, an improved frame differencing method is introduced for better feature extraction and a hough transform method is adopted for rotational angle calculation. A number of experiments are conducted for anomaly detection of single and multiple switches using video frames. The results of the experiments demonstrate that the SSD outperforms the You-Only-Look-Once network. The effectiveness and robustness of the proposed method have been proven under various conditions, such as different illumination and camera locations using 96 videos from the experiments.
Wang, Hao,Duan, Xiang-Long,Qi, Xiao-Li,Meng, Lei,Xu, Yi-Song,Wu, Tong,Dai, Peng-Gao Korean Society for Molecular and Cellular Biology 2017 Molecules and cells Vol.40 No.1
Aberrant hypermethylation of Wnt antagonists has been observed in gastric cancer. A number of studies have focused on the hypermethylation of a single Wnt antagonist and its role in regulating the activation of signaling. However, how the Wnt antagonists interacted to regulate the signaling pathway has not been reported. In the present study, we systematically investigated the methylation of some Wnt antagonist genes (SFRP2, SFRP4, SFRP5, DKK1, DKK2, and APC) and their regulatory role in carcinogenesis. We found that aberrant promoter methylation of SFRP2, SFRP4, DKK1, and DKK2 was significantly increased in gastric cancer. Moreover, concurrent hypermethylation of SFRP2 and DKK2 was observed in gastric cancer and this was significantly associated with increased expression of ${\beta}-catenin$, indicating that the joint inactivation of these two genes promoted the activation of the Wnt signaling pathway. Further analysis using a multivariate Cox proportional hazards model showed that DKK2 methylation was an independent prognostic factor for poor overall survival, and the predictive value was markedly enhanced when the combined methylation status of SFRP2 and DKK2 was considered. In addition, the methylation level of SFRP4 and DKK2 was correlated with the patient's age and tumor differentiation, respectively. In conclusion, epigenetic silencing of Wnt antagonists was associated with gastric carcinogenesis, and concurrent hypermethylation of SFRP2 and DKK2 could be a potential marker for a prognosis of poor overall survival.