Ultrasonic guided wave approach incorporating SAFE for detecting wire breakage in bridge cable

Pengfei Zhang,Zhifeng Tang,Yuanfeng Duan,Chung Bang Yun,Fuzai Lv 국제구조공학회 2018 Smart Structures and Systems, An International Jou Vol.22 No.4

Ultrasonic guided waves have attracted increasing attention for non-destructive testing (NDT) and structural health monitoring (SHM) of bridge cables. They offer advantages like single measurement, wide coverage of acoustical field, and long-range propagation capability. To design defect detection systems, it is essential to understand how guided waves propagate in cables and how to select the optimal excitation frequency and mode. However, certain cable characteristics such as multiple wires, anchorage, and polyethylene (PE) sheath increase the complexity in analyzing the guided wave propagation. In this study, guided wave modes for multi-wire bridge cables are identified by using a semi-analytical finite element (SAFE) technique to obtain relevant dispersion curves. Numerical results indicated that the number of guided wave modes increases, the length of the flat region with a low frequency of L(0,1) mode becomes shorter, and the cutoff frequency for high order longitudinal wave modes becomes lower, as the number of steel wires in a cable increases. These findings were used in design of transducers for defect detection and selection of the optimal wave mode and frequency for subsequent experiments. A magnetostrictive transducer system was used to excite and detect the guided waves. The applicability of the proposed approach for detecting and locating wire breakages was demonstrated for a cable with 37 wires. The present ultrasonic guided wave method has been found to be very responsive to the number of broken wires and is thus capable of detecting defects with varying sizes.

Ultrasonic guided wave approach incorporating SAFE for detecting wire breakage in bridge cable

Zhang, Pengfei,Tang, Zhifeng,Duan, Yuanfeng,Yun, Chung Bang,Lv, Fuzai 국제구조공학회 2018 Smart Structures and Systems, An International Jou Vol.22 No.4

Ultrasonic guided waves have attracted increasing attention for non-destructive testing (NDT) and structural health monitoring (SHM) of bridge cables. They offer advantages like single measurement, wide coverage of acoustical field, and long-range propagation capability. To design defect detection systems, it is essential to understand how guided waves propagate in cables and how to select the optimal excitation frequency and mode. However, certain cable characteristics such as multiple wires, anchorage, and polyethylene (PE) sheath increase the complexity in analyzing the guided wave propagation. In this study, guided wave modes for multi-wire bridge cables are identified by using a semi-analytical finite element (SAFE) technique to obtain relevant dispersion curves. Numerical results indicated that the number of guided wave modes increases, the length of the flat region with a low frequency of L(0,1) mode becomes shorter, and the cutoff frequency for high order longitudinal wave modes becomes lower, as the number of steel wires in a cable increases. These findings were used in design of transducers for defect detection and selection of the optimal wave mode and frequency for subsequent experiments. A magnetostrictive transducer system was used to excite and detect the guided waves. The applicability of the proposed approach for detecting and locating wire breakages was demonstrated for a cable with 37 wires. The present ultrasonic guided wave method has been found to be very responsive to the number of brokenwires and is thus capable of detecting defects with varying sizes.

Fluorescent Nitrogen-Doped Carbon Dots via Single-Step Synthesis Applied as Fluorescent Probe for the Detection of Fe3+ Ions and Anti-Counterfeiting Inks

Chonghui Fan,Kelong Ao,Pengfei Lv,Jiancheng Dong,Di Wang,Yibing Cai,Qufu Wei,Yang Xu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.08

Fluorescent nitrogen-doped carbon dots (N-CDs) with excellent stability were prepared via single-step hydrothermal carbonization of citric acid (CA) and ethylenediamine (EDA). The as-prepared N-CDs emit blue fluorescence under the excitation of 365 nm and have a size distribution of 2.80 ffi 0.47 nm with benign size effect. The structure and morphology were further characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. It was found that the surface of the N-CDs was successfully functionalized, which presented water solubility and chelation with Fe3+. XRD results display a diffraction peak at 23.9 ℃, which corresponds to the (002) interlayer spacing of a graphitic structure revealing an amorphous carbon phase. Furthermore, due to good sensitivity, N-CDs were used as probes for Fe3+ detection. The low limit of detection of 0.6 μM as a fluorescence probe was successfully obtained based on the linear relationship between (F0 - F) / F0 and concentration of Fe3+ ions. Besides the satisfactory fluorescence, PVA/N-CDs membranes and fluorescent inks demonstrate potential for anti-counterfeiting applications due to its characteristic flexibility, transparency, removability and invisibility under ambient lighting.

Graphene Oxide/Polyester Fabric Composite by Electrostatic Self-Assembly as a New Recyclable Adsorbent for the Removal of Methylene Blue

Di Wang,Dawei Li,Pengfei Lv,Qingqing Wang,Yang Xu,Qufu Wei 한국섬유공학회 2018 Fibers and polymers Vol.19 No.8

A novel graphene oxide/polyester (GO/PET) composite fabric as a recyclable adsorbent was prepared via electrostatic self-assembly. The structure, morphology, and properties of the GO/PET composite fabrics were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transformed infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and contact angle (CA), respectively. The absorption property was evaluated by the absorption amount and removal efficiency of methylene blue (MB) solution on the GO/PET composite fabric. The results indicated that the absorption amount was found to be 21.80 mg/g and the removal efficiency reached 99.93 % under the experimental conditions of GO concentration of 2 mg/ml, initial concentration of 50 mg/l, and area of 64 cm2. The experimental parameters were investigated including the concentration of GO, the initial concentration of MB solutions, and adsorbent area. Simultaneously, according to a series of dynamic analysis, the absorption process revealed that the kinetics was well-described by pseudo-second-order model. This study showed that the GO/PET composite fabric could be a recyclable, efficient adsorbent material for the environmental cleanup.

Fertility-preserving treatment outcome in endometrial cancer or atypical hyperplasia patients with polycystic ovary syndrome

Lulu Wang,Xuezhen Luo,Qian Wang,Qiaoying Lv,Pengfei Wu,Wei Liu,Xiaojun Chen 대한부인종양학회 2021 Journal of Gynecologic Oncology Vol.32 No.5

Objective: This study aimed to investigate the impact of polycystic ovary syndrome (PCOS) on fertility-sparing treatment in young patients with atypical endometrial hyperplasia (AEH) or endometrioid endometrial cancer (EEC). Methods: A total of 285 patients with EEC (n=76, FIGO stage IA, without myometrium invasion) or AEH (n=209) who received progestin-based fertility-sparing treatment were evaluated retrospectively. Among the 285 patients, 103 (36.1%), including 70 AEH cases and 33 EEC cases, were diagnosed with PCOS. General characteristics, cumulative 16- and 32-week complete response (CR) rate, pregnancy outcome and recurrence were compared between patients with or without PCOS. Results: The cumulative 16-week CR rate was lower in the PCOS group than in the non- PCOS group (18.4% vs. 33.8%, p=0.006). Patients with PCOS took longer treatment duration to achieve CR (7.0 months vs. 5.4 months, p=0.006) and shorter time to relapse after CR (9.6 months vs. 17.6 months, p=0.040) compared with non-PCOS group. After adjusting for patient age, body mass index, PCOS, homeostasis model assessment-insulin resistance index, and serum testosterone levels, we found that body mass index ≥25 kg/m2 (HR=0.583; 95% CI=0.365–0.932; p=0.024) and PCOS (HR=0.545; 95% CI=0.324–0.917; p=0.022) were significantly correlated with lower 16-week CR rate. Conclusion: PCOS was associated with lower 16-week CR rate, longer treatment duration and shorter recurrence interval in patients with AEH or EEC receiving fertility-preserving treatment.

Management of COVID-19-related immune thrombocytopenia by rhTPO

Xuzhao Zhang,Min Li,Tao Chen,Dong Lv,Pengfei Xia,Wenbin Qian 대한혈액학회 2021 Blood Research Vol.56 No.3

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Predicting Pathological Complete Response in Breast Cancer After Two Cycles of Neoadjuvant Chemotherapy by Tumor Reduction Rate: A Retrospective Case-Control Study

Litong Yao,Xiaoyan Liu,Mozhi Wang,Keda Yu,Shouping Xu,Pengfei Qiu,Zhidong Lv,Xinwen Zhang,Yingying Xu 한국유방암학회 2023 Journal of breast cancer Vol.26 No.2

Purpose: We aimed to identify effectiveness-associated indicators and evaluate the optimal tumor reduction rate (TRR) after two cycles of neoadjuvant chemotherapy (NAC) in patients with invasive breast cancer. Methods: This retrospective case-control study included patients who underwent at least four cycles of NAC at the Department of Breast Surgery between February 2013 and February 2020. A regression nomogram model for predicting pathological responses was constructed based on potential indicators. Results: A total of 784 patients were included, of whom 170 (21.68%) reported pathological complete response (pCR) after NAC and 614 (78.32%) had residual invasive tumors. The clinical T stage, clinical N stage, molecular subtype, and TRR were identified as independent predictors of pCR. Patients with a TRR > 35% were more likely to achieve pCR (odds ratio, 5.396; 95% confidence interval [CI], 3.299–8.825). The receiver operating characteristic (ROC) curve was plotted using the probability value, and the area under the ROC curve was 0.892 (95% CI, 0.863–0.922). Conclusion: TRR > 35% is predictive of pCR after two cycles of NAC, and an early evaluation model using a nomogram based on five indicators, age, clinical T stage, clinical N stage, molecular subtype, and TRR, is applicable in patients with invasive breast cancer.