Time-domain simulations of transient response in LiFePO4 cathode lithium ion batteries

Xiaoping Xu,Miao Shui,Weidong Zheng,Jie Shu,Lei Hui,Linxia Xu,Liangliang Cheng,Lin Feng,Yuanlong Ren 한국물리학회 2014 Current Applied Physics Vol.14 No.5

The time domain transients of batteries comprised of LiFePO4 cathode material exhibit large nonlinearity with the increasing discharging rates. Hence, the calculated overpotential transients match the experimental determined well only when the discharging current is low enough. The results of electrochemical impedance spectra at different OCV level indicate that the change of the parameters of equivalent circuit or even the circuit architecture are probably responsible for the large discrepancy between the predicted and the measured transient profiles. By taking the change of equivalent circuit model at high discharging current into consideration, we successfully simulate the time domain transients of polarization within the entire discharging current range. Also with the help of circuit analysis, the contribution of the ohmic resistance, charge transfer impedance and solid-state diffusion impedance to total polarization has been differentiated as a function of discharging time.

Fluoroscopically Guided Three-Tube Insertion for the Treatment of Postoperative Gastroesophageal Anastomotic Leakage

Guowen Yin,Qingyu Xu,Shixi Chen,Xiangjun Bai,Feng Jiang,Qin Zhang,Lin Xu,Weidong Xu 대한영상의학회 2012 Korean Journal of Radiology Vol.13 No.2

Objective: To retrospectively evaluate the feasibility and effectiveness of three-tube insertion for the treatment of postoperative gastroesophageal anastomotic leakage (GEAL). Materials and Methods: From January 2007 to January 2011, 28 cases of postoperative GEAL after an esophagectomy with intrathoracic esophagogastric anastomotic procedures for esophageal and cardiac carcinoma were treated by the insertion of three tubes under fluoroscopic guidance. The three tubes consisted of a drainage tube through the leak, a nasogastric decompression tube, and a nasojejunum feeding tube. The study population consisted of 28 patients (18 males, 10 females) ranging in their ages from 36 to 72 years (mean: 59 years). We evaluated the feasibility of three-tube insertion to facilitate leakage site closure, and the patients’ nutritional benefit by checking their serum albumin levels between pre- and post-enteral feeding via the feeding tube. Results: The three tubes were successfully placed under fluoroscopic guidance in all twenty-eight patients (100%). The procedure times for the three tube insertion ranged from 30 to 70 minutes (mean time: 45 minutes). In 27 of 28 patients (96%), leakage site closure after three-tube insertion was achieved, while it was not attained in one patient who received stent implantation as a substitute. All patients showed good tolerance of the three-tube insertion in the nasal cavity. The mean time needed for leakage treatment was 21 ± 3.5 days. The serum albumin level change was significant, increasing from pre-enteral feeding (2.5 ± 0.40 g/dL) to post-enteral feeding (3.7 ± 0.51 g/dL) via the feeding tube (p < 0.001). The duration of follow-up ranged from 7 to 60 months (mean: 28 months). Conclusion: Based on the results of this study, the insertion of three tubes under fluoroscopic guidance is safe, and also provides effective relief from postesophagectomy GEAL. Moreover, our findings suggest that three-tube insertion may be used as the primary procedure to treat postoperative GEAL. Objective: To retrospectively evaluate the feasibility and effectiveness of three-tube insertion for the treatment of postoperative gastroesophageal anastomotic leakage (GEAL). Materials and Methods: From January 2007 to January 2011, 28 cases of postoperative GEAL after an esophagectomy with intrathoracic esophagogastric anastomotic procedures for esophageal and cardiac carcinoma were treated by the insertion of three tubes under fluoroscopic guidance. The three tubes consisted of a drainage tube through the leak, a nasogastric decompression tube, and a nasojejunum feeding tube. The study population consisted of 28 patients (18 males, 10 females) ranging in their ages from 36 to 72 years (mean: 59 years). We evaluated the feasibility of three-tube insertion to facilitate leakage site closure, and the patients’ nutritional benefit by checking their serum albumin levels between pre- and post-enteral feeding via the feeding tube. Results: The three tubes were successfully placed under fluoroscopic guidance in all twenty-eight patients (100%). The procedure times for the three tube insertion ranged from 30 to 70 minutes (mean time: 45 minutes). In 27 of 28 patients (96%), leakage site closure after three-tube insertion was achieved, while it was not attained in one patient who received stent implantation as a substitute. All patients showed good tolerance of the three-tube insertion in the nasal cavity. The mean time needed for leakage treatment was 21 ± 3.5 days. The serum albumin level change was significant, increasing from pre-enteral feeding (2.5 ± 0.40 g/dL) to post-enteral feeding (3.7 ± 0.51 g/dL) via the feeding tube (p < 0.001). The duration of follow-up ranged from 7 to 60 months (mean: 28 months). Conclusion: Based on the results of this study, the insertion of three tubes under fluoroscopic guidance is safe, and also provides effective relief from postesophagectomy GEAL. Moreover, our findings suggest that three-tube insertion may be used as the primary procedure to treat postoperative GEAL.

Formation of Hyperbranched Amphiphilic Terpolymers and Unimolecular Micelles in One-pot Copolymerization

Xu Wang,Lianwei Li,Weidong He,Chi Wu 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2

Delamination identification of laminated composite plates using measured mode shapes

Yongfeng Xu,Da-Ming Chen,Weidong Zhu,Guoyi Li,Aditi Chattopadhyay 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.23 No.2

An accurate non-model-based method for delamination identification of laminated composite plates is proposed in this work. A weighted mode shape damage index is formulated using squared weighted difference between a measured mode shape of a composite plate with delamination and one from a polynomial that fits the measured mode shape of the composite plate with a proper order. Weighted mode shape damage indices associated with at least two measured mode shapes of the same mode are synthesized to formulate a synthetic mode shape damage index to exclude some false positive identification results due to measurement noise and error. An auxiliary mode shape damage index is proposed to further assist delamination identification, by which some false negative identification results can be excluded and edges of a delamination area can be accurately and completely identified. Both numerical and experimental examples are presented to investigate effectiveness of the proposed method, and it is shown that edges of a delamination area in composite plates can be accurately and completely identified when measured mode shapes are contaminated by measurement noise and error. In the experimental example, identification results of a composite plate with delamination from the proposed method are validated by its C-scan image.

A NOTE ON THE FINITE-DIMENSIONAL ODD CONTACT SUPERALGEBRA OVER A FIELD OF PRIME CHARACTERISTIC

Hong, Weidong,Xu, Xiaoning Korean Mathematical Society 2021 대한수학회보 Vol.58 No.5

This paper aims to analyze the PTG module for the finite-dimensional odd Contact superalgebra over a field of prime characteristic by using the method of Hu and Shen's mixed product realization. The general acting law in odd Contact superalgebra is obtained. In addition, the structure and irreducibility of graded module for odd Contact superalgebra are discussed.

Classification of Motor Imagery Tasks for Electrocorticogram Based Brain-Computer Interface

Fangzhou Xu,Weidong Zhou,Yilin Zhen,Qi Yuan 대한의용생체공학회 2014 Biomedical Engineering Letters (BMEL) Vol.4 No.2

Purpose In the present study, we propose a novel schemefor motor imagery (MI) classification of multichannelelectrocorticogram (ECoG) recordings from patients withmedically intractable focal epilepsy. Methods This scheme proposes a combination of the twofeatures which includes autoregressive (AR) model coefficientsand local binary pattern (LBP) operators. It can providespatial resolution and angular space information. Then thegradient boosting (GB) in conjunction with ordinary leastsquares (OLS) algorithm is employed as the classifier toimprove the performance of MI classification for ECoGbased Brain Computer Interface (BCI) system. Results Experimental results on the BCI Competition IIIdata set I indicate that the novel method has excellentperformance and yields a cross-validation accuracy of 88.8%and accuracy of 93%, respectively. Conclusions From the experimental results and comparativestudies, we can infer that the scheme may serve as a good MIclassification tool for a better tradeoff between the classificationaccuracy and computational complexity.

A modified U-net for crack segmentation by Self-Attention-Self-Adaption neuron and random elastic deformation

Yang Xu,Jin Zhao,Fangqiao Hu,Weidong Qiao,Weida Zhai,Yuequan Bao,Hui Li 국제구조공학회 2022 Smart Structures and Systems, An International Jou Vol.29 No.1

Despite recent breakthroughs in deep learning and computer vision fields, the pixel-wise identification of tiny objects in high-resolution images with complex disturbances remains challenging. This study proposes a modified U-net for tiny crack segmentation in real-world steel-box-girder bridges. The modified U-net adopts the common U-net framework and a novel Self-Attention-Self-Adaption (SASA) neuron as the fundamental computing element. The Self-Attention module applies softmax and gate operations to obtain the attention vector. It enables the neuron to focus on the most significant receptive fields when processing large-scale feature maps. The Self-Adaption module consists of a multiplayer perceptron subnet and achieves deeper feature extraction inside a single neuron. For data augmentation, a grid-based crack random elastic deformation (CRED) algorithm is designed to enrich the diversities and irregular shapes of distributed cracks. Grid-based uniform control nodes are first set on both input images and binary labels, random offsets are then employed on these control nodes, and bilinear interpolation is performed for the rest pixels. The proposed SASA neuron and CRED algorithm are simultaneously deployed to train the modified U-net. 200 raw images with a high resolution of 4928 × 3264 are collected, 160 for training and the rest 40 for the test. 512 × 512 patches are generated from the original images by a sliding window with an overlap of 256 as inputs. Results show that the average IoU between the recognized and ground-truth cracks reaches 0.409, which is 29.8% higher than the regular U-net. A five-fold cross-validation study is performed to verify that the proposed method is robust to different training and test images. Ablation experiments further demonstrate the effectiveness of the proposed SASA neuron and CRED algorithm. Promotions of the average IoU individually utilizing the SASA and CRED module add up to the final promotion of the full model, indicating that the SASA and CRED modules contribute to the different stages of model and data in the training process.

Systemic Delivery of an Oncolytic Adenovirus Expressing Decorin for the Treatment of Breast Cancer Bone Metastases

Yang, Yuefeng,Xu, Weidong,Neill, Thomas,Hu, Zebin,Wang, Chi-Hsiung,Xiao, Xianghui,Stock, Stuart R.,Guise, Theresa,Yun, Chae-Ok,Brendler, Charles B.,Iozzo, Renato V.,Seth, Prem Mary Ann Liebert, Inc. Publishers 2015 Human gene therapy Vol.26 No.12

Clonal Spread of Carbapenem Non-susceptible Acinetobacter baumannii in an Intensive Care Unit in a Teaching Hospital in China

Qiao Zhong,Weidong Xu,Yuanjian Wu,Hongxing Xu 대한진단검사의학회 2012 Annals of Laboratory Medicine Vol.32 No.6

Background: This study was aimed to investigate the genetic diversity and antibiotic resistance profile of the nosocomial infection agent Acinetobacter baumannii from a medical intensive care unit (ICU) in a teaching hospital in Suzhou, China. Methods: The genetic relationship among A. baumannii isolates in an ICU was investigated using multilocus sequence typing (MLST). The antibiotic resistance pattern was determined by performing an antibiotic susceptible test, which included an agar dilution method and an E-test method. Resistant determinants, e.g., carbapenemase genes, metallo-β- lactamases, and class 1 integron, were analyzed by specific PCR and DNA sequencing. Results: In the present study, 33 non-duplicate isolates were identified as 5 existing sequence types (STs) (ST92, ST75, ST112, ST145, and ST345) and 1 new sequence type STn, which has a G-A mutation at nt268 on ropD40 of ST251. These results reveal limited diversity in carbapenem non-susceptible A. baumannii (CNSAb) isolates in our ICU, which are comprised of only 2 distinct STs, with ST92 and ST75 clustering into a clonal complex (CC) 92. Most CNSAb isolates (94.4%, 17/18) harbored the OXA-23 gene, while no carbapenem-susceptible A. baumannii (CSAb) isolates harbored it. In addition, 66.7% (22/33) isolates were positive for class 1 integrase, and gene cassette analysis showed there are 3 gene arrays among them, i.e., aacA4-catB8-aadA1 (77.3%, 17/22), aacA4 (22.7%, 5/22), and aacC1-orfX-orfX’-aadA1 (4.5%, 1/22). Conclusions: When all these data are combined, the antibiotic resistance and wide distribution of CNSAb isolates in our ICU are probably caused by expansion of the CC92 clone. Background: This study was aimed to investigate the genetic diversity and antibiotic resistance profile of the nosocomial infection agent Acinetobacter baumannii from a medical intensive care unit (ICU) in a teaching hospital in Suzhou, China. Methods: The genetic relationship among A. baumannii isolates in an ICU was investigated using multilocus sequence typing (MLST). The antibiotic resistance pattern was determined by performing an antibiotic susceptible test, which included an agar dilution method and an E-test method. Resistant determinants, e.g., carbapenemase genes, metallo-β- lactamases, and class 1 integron, were analyzed by specific PCR and DNA sequencing. Results: In the present study, 33 non-duplicate isolates were identified as 5 existing sequence types (STs) (ST92, ST75, ST112, ST145, and ST345) and 1 new sequence type STn, which has a G-A mutation at nt268 on ropD40 of ST251. These results reveal limited diversity in carbapenem non-susceptible A. baumannii (CNSAb) isolates in our ICU, which are comprised of only 2 distinct STs, with ST92 and ST75 clustering into a clonal complex (CC) 92. Most CNSAb isolates (94.4%, 17/18) harbored the OXA-23 gene, while no carbapenem-susceptible A. baumannii (CSAb) isolates harbored it. In addition, 66.7% (22/33) isolates were positive for class 1 integrase, and gene cassette analysis showed there are 3 gene arrays among them, i.e., aacA4-catB8-aadA1 (77.3%, 17/22), aacA4 (22.7%, 5/22), and aacC1-orfX-orfX’-aadA1 (4.5%, 1/22). Conclusions: When all these data are combined, the antibiotic resistance and wide distribution of CNSAb isolates in our ICU are probably caused by expansion of the CC92 clone.

p-Doping of organic hole transport layers in p-i-n perovskite solar cells: correlating open-circuit voltage and photoluminescence quenching

Du, Tian,Xu, Weidong,Daboczi, Matyas,Kim, Jinhyun,Xu, Shengda,Lin, Chieh-Ting,Kang, Hongkyu,Lee, Kwanghee,Heeney, Martin J.,Kim, Ji-Seon,Durrant, James R.,McLachlan, Martyn A. The Royal Society of Chemistry 2019 Journal of Materials Chemistry A Vol.7 No.32

<P>Doping is a widely implemented strategy for enhancing the inherent electronic properties of charge transport layers in photovoltaic (PV) devices. Here, in direct contrast to existing understanding, we find that a reduction in p-doping of the organic hole transport layer (HTL) leads to substantial improvements in PV performance in planar p-i-n perovskite solar cells (PSCs), driven by improvements in open circuit voltage (<I>V</I>OC). Employing a range of transient and steady state characterisation tools, we find that the improvements of <I>V</I>OC correlate with reduced surface recombination losses in less p-doped HTLs. A simple device model including screening of bulk electric fields in the perovskite layer is used to explain this observation. In particular, photoluminescence (PL) emission of complete solar cells shows that efficient performance is correlated to a high PL intensity at open circuit and a low PL intensity at short circuit. We conclude that desirable transport layers for p-i-n PSCs should be charge selective contacts with low doping densities.</P>