Effect of oxidizing treatment on electrocatalytic activity of boron‑doped amorphous carbon thin films

Chen‑Song Wang,Ni Suo,Hao Huang,Ai‑min Wu,Guo‑Zhong Cao,Gui‑Feng Zhang 한국탄소학회 2019 Carbon Letters Vol.29 No.5

Boron-doped amorphous carbon (BDAC) thin films with a regular oxygen reduction reaction (ORR) catalytic activity were synthesized in a hot filament chemical vapor deposition device using a mixture of CH4 and H2 as a gas source and B2O3 as a boron source and then oxidized in air at 380–470 °C for 15–75 min. Scanning electron microscope, transmission electron microscope, Raman spectroscopy, X-ray photoelectron spectroscopy, and electrochemical tests were used to characterize the physical and electrochemical properties of the BDAC catalysts. It was concluded that the BDAC catalyst oxidized at 450 °C for 45 min showed the best ORR catalytic activity in alkaline medium. The oxygen reduction potential and the transfer electron number n, respectively, are − 0.286 V versus Ag/AgCl and 3.24 from the rotating disk electrode experiments. The treated carbon film has better methanol resistance and stability than the commercial Pt/C catalyst.

Adaptive Separation Model for Electromagnetic Pulse Coupling Signals of Engine Digital Controllers

Chen Kai,Wei Minxiang,Cao Jie,Chen Xinda,Li Shunming 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.4

The engine digital controller is vulnerable to attacks of wide-spectrum and uncertain electromagnetic pulses (EMPs). To address this issue, herein, we propose a novel “internal cluster evaluation cluster” clustering integrated signal separation method and establish an adaptive separation model for EMP coupling signals of engine digital controllers. Specifi cally, the proposed method mainly includes generation of base clusterings to form a candidate pool of base clusterings, evaluation of the uncertainty of clusters, and establishing an integration strategy. To verify the model, we adopt two types of EMP coupling signal data for simulation and actual measurement. The proposed method is compared with fi ve typical clustering ensemble methods in terms of their normalized mutual information (NMI) values. For the simulated EMP coupled signal data, the hyperparameter is 0.4, and the NMI values of fi ve sets of data are 0.721, 0.576, 0.329, 0.201, and 0.466. For the measured data, the hyperparameter is 0.8, and the NMI values of fi ve sets of data are 0.738, 0.555, 0.377, 0.511, and 0.485. The NMI values of the two types of EMP coupling signal data of the proposed method are generally better than those of the other classical methods. The results confi rm the superior separation eff ect of the proposed method on EMP coupled signals.

Flash Flood Hazard Susceptibility Mapping Using Two Statistical Methods in Coalmine Subsidence Areas

( Chen Cao ),( Peihua Xu ),( Jianping Chen ),( Qing Wang ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2

This study focused on producing flash flood hazard susceptibility maps (FFHSM) using frequency ratio (FR) and statistical index (SI) models in the Xiqu Gully (XQG) of Beijing, China. First, a total of 85 flash flood hazard locations (n= 85) were surveyed in the field and plotted using geographic information system (GIS) software. Based on the flash flood hazard locations, a flood hazard inventory map was built. Seventy percent of the flooding hazard locations were randomly selected for building the models. The remaining 30% of the flooded hazard locations were used for validation. XQG used to be a coal mining area, coalmine caves and subsidence caused by coal mining exist in this catchment, as well as many ground fissures. Thus, this study took the subsidence risk level into consideration for FFHSM. The ten conditioning parameters were elevation, slope, curvature, land use, geology, soil texture, subsidence risk area, stream power index (SPI), topographic wetness index (TWI), and short-term heavy rain. This study also tested different classification schemes for the values for each conditional parameter and checked their impacts on the results. The accuracy of the FFHSM was validated using area under the curve (AUC) analysis. Classification accuracies were 86.61%, 83.35%, and 78.52% using frequency ratio (FR)-natural breaks, statistical index (SI)-natural breaks and FR-manual classification schemes, respectively. Associated prediction accuracies were 83.69%, 81.22%, and 74.23%, respectively. It was found that FR modeling using a natural breaks classification method was more appropriate for generating FFHSM for the Xiqu Gully.

Clinical Predictive Value of Serum Angiogenic Factor in Patients with Osteosarcoma

Chen, Zhe,Chen, Qi-Xin,Hou, Zhao-Yang,Hu, Jiong,Cao, Yan-Guang Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.9

Objective: To explore serum angiogenic factor expression in patients with osteosarcoma and its relationship with metastasis. Methods: Immunohistochemistry was used to test the expression of CD34 and FVIII-Rag in osteosarcoma tissues of 36 patients (osteosarcoma group) and microvessel density (MVD) was also recorded. In addition, ELISA was used to test the level of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), transforming growth factor-${\beta}1$ (TGF-${\beta}1$) and endostatin (ES) in the osteosarcoma group and in a control group. Results: VEGF and ES level were significantly higher than in the control group before operation (P<0.01), VEGF, bFGF and TGF-${\beta}1$ correlating with the ES level (P<0.01). Serum VEGF and ES levels of osteosarcoma patients before surgery were closely related to relapse and metastasis; moreover, serum VEGF increased with MVD (P<0.01). Postoperative VEGF and ES levels were lower than the preoperation values (P<0.01); ES level in relapse group was significantly higher than that of the non-relapse group (P<0.01). Conclusion: Preoperative serum VEGF and postoperative ES levels have great predictive value with regard to relapse of osteosarcoma patients.

Expression and Prognostic Role of MEKK3 and pERK in Patients with Renal Clear Cell Carcinoma

Chen, Qi,Lu, Hong-sheng,Gan, Mei-fu,Chen, Lan-xi,He, Kai,Fan, Guang-min,Cao, Xue-quan Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.6

Mitogen-activated protein kinase/extracellular signal-regulated kinase kinase kinase 3 (MEKK3) is an important serine/threonine protein kinase and a member of the MAPK family. MEKK3 can effectively activate the MEK/ERK signaling pathway and promote an autocrine growth loop critical for tumor genesis, cell proliferation, terminal differentiation, apoptosis and survival. To explore the relationship between MEKK3 and cell apoptosis, clinicopathology and prognosis, we characterize the expression of MEKK3, pERK and FoxP3 in the renal clear cell carcinoma (RCCC). Protein expression was detected by tissue microarray and immunochemistry in 46 cases of RCCC and 28 control cases. Expression levels of CD3+,CD3+CD4+,CD3+CD8+,CD4+CD25+, CD4+CD25+ FoxP3+ were assessed by flow cytometry and analyzed for their association with pathological factors, correlation and prognosis in RCCC. Expression of MEKK3, pERK and FoxP3 was significantly up-regulated in RCCC as compared to control levels (p<0.01), associated with pathological grade (p<0.05)and clinical stage (p<0.05). CD4+CD25+ Foxp3+ Treg cells were also significantly increased in RCCC patients (p<0.05). Cox multivariate regression analysis showed that MEKK3, pERK expression and patholigical stage were independent prognostic factors in patients with RCCC (p<0.05). MEKK3 can be used as an important marker of early diagnosis and prognostic evaluation in RCCC. It may be associated with imbalance of anti-tumor immunity and overexpression of pERK. Expression of MEKK3 and pERK are significantly increased in RCCC, with protein expression and clinical stage acting as independent prognostic factors.

An Improved African Vulture Optimization for Biding Strategy of Two-Settlement Market in China

Cao Wei,Chen Xiao,Cao Zhiwei,Badami Benjamin 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2

The present study introduces a new optimal bidding strategy (BS) in the Two-settlement market for a case study in China. Here, an enhanced design of the African Vulture Optimizer (AVO) is utilized for optimizing the process based on the market-clearing price probability function. Subtractive clustering is also used for the similarity measures clustering between the present day and the later day. Non-decreasing bidding curves and a cap price bordered about 70 $/MWh has been considered for the production part of the day-ahead market competition. Also, the hourly maximum power of the generation company and hourly market clearing price are considered for providing a suitable examination of the model in the dataset. The optimal bidding strategy in this study is used to testify on bidding data from China from 2010 to 2019. Simulation results show that the average return in the company of generation in the sets raise to 25.84% and 13.83% compared with Model 1 as a simple model and Model 2 with a Q-Learning model, respectively which is for China's real electricity market.

A RIF Based Mapping of RDB2RDF

Ying Chen,Zhuoming Xu,Yuyan Ni,Guangxu Cao,Shiqing Zhang 보안공학연구지원센터 2014 International Journal of Database Theory and Appli Vol.7 No.6

Mapping RDB to RDF (i.e., RDB2RDF) is the key to constructing the Semantic Web, hence has been an active research field during the last decade. Many technically heterogeneous RDB2RDF tools resulted in non-interchangeable and unreusable RDB2RDF mapping descriptions. In 2009, the W3C RDB2RDF Incubator Group Report once strongly suggested that the RDB2RDF mapping language be expressed in rules as defined by the W3C Rule Interchange Format (RIF) Working Group, because rules are an effective way to express mappings between information models, and RIF, as part of the infrastructure for the Semantic Web, is now a standard for exchanging rules among Web rule systems. This paper addresses the issue of RIF-based RDB2RDF mapping and proposes a database semantics-driven, RIF Production Rule Dialect (RIF-PRD) based mapping description approach. The work includes defining a set of generic RIF-PRD mapping rules for RDB2RDF, developing a prototype mapping engine called RIFD2RME (stands for RIF-based RDB2RDF Mapping Engine), and conducting case study experiments with the prototype. The experimental results indicate that the proposed mapping approach is achievable and effective.

Paranasal Sinus Invasion in Nasopharyngeal Carcinoma after Intensity-Modulated Radiotherapy

Caineng Cao,Feng Jiang,Qifeng Jin,Ting Jin,Shuang Huang,Qiaoying Hu,Yuanyuan Chen,Yongfeng Piao,Yonghong Hua,Xinglai Feng,Xiaozhong Chen 대한암학회 2019 Cancer Research and Treatment Vol.51 No.1

Purpose The aim of this study is to evaluate the prognostic significance of paranasal sinus invasion for nasopharyngeal carcinoma (NPC) and its suitable position in the T classification. Materials and Methods The magnetic resonance imaging (MRI) scans of 695 patients with previously untreated, biopsy-proven, non-metastatic NPC that was treated with intensity-modulated radiotherapy (IMRT) were reviewed retrospectively. Results The incidence of paranasal sinus invasion was 39.4% (274 of 695 patients). Multivariate analysis showed that paranasal sinus invasion was an independent negative prognostic factor for local failure-free survival (LFFS) (p < 0.05). According to the eighth American Joint Committee on Cancer (AJCC) staging system, 275 patients were classified as T3 classification. Of these, 78 patients (28.4%) developed paranasal sinus invasion (T3b) and 197 (71.6%) didn’t (T3a). The estimated 5-year LFFS and overall survival (OS) rates for the patients with T3b and T3a classification were 88.6% versus 95.0% (p=0.047), and 84.5% versus 93.3% (p=0.183), respectively. The estimated 5-year LFFS and OS rates for the patients with T4 classification were 89.5% and 83.2%, which were similar with the outcomes of patients with T3b classification. Conclusion MRI-determined paranasal sinus invasion is an independent prognostic factor of NPC treated by IMRT. Paranasal sinus invasion is recommended to classify as T4 classification in the 8th AJCC staging system for NPC.

Experimental study on vibration serviceability of cold-formed thin-walled steel floor

Bin Chen,Liang Cao,Faming Lu,Y. Frank Chen 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.46 No.4

In this study, on-site testing was carried out to investigate the vibration performance of a cold-formed thin-walled steel floor system. Ambient vibration, walking excitation (single and double persons), and impulsive excitation (heel-drop and jumping) were considered to capture the primary vibration parameters (natural frequencies, damping ratios, and mode shapes) and vertical acceleration response. Meanwhile, to discuss the influence of cement fiberboard on structural vibration, the primary vibration parameters were compared between the systems with and without the installation of cement fiberboard. Based on the experimental analysis, the cold-formed thin-walled steel floor possesses high frequency (> 10 Hz) and damping (> 2%); the installed cement fiberboard mainly increases the mass of floor system without effectively increasing the floor stiffness and may reduce the effects of primary vibration parameters on acceleration response; and the human-structure interaction should be considered when analyzing the vibration serviceability. The comparison of the experimental results with those in the AISC Design Guide indicates that the cold-formed thin-walled steel floor exhibits acceptable vibration serviceability. A crest factor βrp (ratio of peak to root-mean-square accelerations) is proposed to determine the root-mean-square acceleration for convenience.

Mechanism analysis of pressure fluctuation in wheel loader articulated steering hydraulic system

Bing-wei Cao,Xinhui Liu,Wei Chen,Chen Zhou,Fei-xiang Xu 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.10

This paper studies the influence of hinge point positioning of a steering cylinder on the pressure fluctuation of the steering system of a wheel loader. Affected by the hinge point position of the steering cylinder, the main causes of the pressure fluctuation are found to be the stroke difference and the force arm difference. Based on theoretical analysis, the hinge point positioning of the steering cylinder was optimized by using genetic algorithm (GA). The AMEsim simulation model of the steering system was built to verify the accuracy of the GA. The wheel loader was reformed according to the optimized articulated points position. Steering tests showed a significant drop in system pressure fluctuation, the energy consumed is also reduced. Further, the analysis shows that the force arm difference is the main factor causing the pressure fluctuation, providing the theoretical and experimental basis for the design of a steering system of wheel loaders.