Wide-Gap Repair of Mar-M247 Superalloy via Powder Metallurgy Route

Xiufang Gong,Yankang Yu,Tianjian Wang,Ye Liu,Lin Zhang,Zhenhuan Gao,Hou Ziyong,Xu Chen,Shuang He,Xuanhui Qu 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.11

Wide-gap defects repair of Mar-M247 superalloy was investigated by utilizing powder metallurgy. New interlayer alloy withrelatively high content of B and Zr was designed based on the isothermal solidification principle. The interlayer alloy ischaracterized by relative low melting temperature (1100 °C), and the contact angle of interlayer on the Mar-M247 substrateis ~ 70º. Based on the thermodynamic calculation results, the mixture powders with 80 wt% substrate powder and 20 wt%interlayer alloy powder was used as a filler to repair the wide gap with width of 2 mm. After repaired at 1230 °C for 2 h, nearfullydense gap was obtained. MC-type carbides, MB2-type boride, M3B2-type boride and Ni5(Zr,Hf)-type intermetallic wereobserved in the liquid zone. After post-weld heat treatment, the block borides, chain carbides and eutectic are successfullyremoved, and the tensile strength of the bonding zone is close to that of the Mar-M247 superalloy.

Research of Image Edge Detection Based on Mathematical Morphology

Xiufang Wang,Xingyuan Zhang,Running Gao 보안공학연구지원센터(IJSIP) 2013 International Journal of Signal Processing, Image Vol.6 No.5

Ce_(0.9)Sr_(0.1)Cr_(0.5)Mn_(0.5)O_(3-δ) as the anode materials for solid oxide fuel cells running on H_2 and H_2S

Xiufang Zhu,Qin Zhong,Han Yan,Xuejun Zhao,Wenyi Tan 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.8

Perovskite-type Ce_(0.9)Sr_(0.1)Cr_(0.5)Mn_(0.5)O_(3-δ) (CSCMn) was synthesized and evaluated as anode for solid oxygen fuel cells based on Ce_(0.8)Sm_(0.2)O_(1.9) (SDC). The conductivities of CSCMn were evaluated with DC four-probe method in 3% H_2-N_2 and 5% H_2S-N_2 at 450-700 ℃, respectively. The compositions of CSCMn powders were studied by XRD and thermodynamic calculations. Meanwhile, sintering temperatures affecting phases of CSCMn is also proposed with XRD, and the analysis is given with thermodynamic calculations. CSCMn exhibits good chemical compatibility with electrolyte (SDC) in N_2. After exposure to 5% H_2S-N_2 for 5 h at 800 ℃, CSCMn crystal structures change and some sulfides are detected, as evidenced by XRD and Raman analyses. The electrochemical properties are measured for the cell comprising CSCMn- SDC/SDC/Ag in 5% H_2S-N_2 at 600 ℃ and in 3% H_2-N_2 at 450 and 500 ℃. The electrochemical impedance spectrum (EIS) is used to analyze ohm and polarization resistance of the cell at various temperatures.

Traffic Flow Prediction Model Based on Spatio-Temporal Dilated Graph Convolution

( Xiufang Sun Jianbo Li ),( Zhiqiang Lv ),( Chuanhao Dong ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.9

With the increase of motor vehicles and tourism demand, some traffic problems gradually appear, such as traffic congestion, safety accidents and insufficient allocation of traffic resources. Facing these challenges, a model of Spatio-Temporal Dilated Convolutional Network (STDGCN) is proposed for assistance of extracting highly nonlinear and complex characteristics to accurately predict the future traffic flow. In particular, we model the traffic as undirected graphs, on which graph convolutions are built to extract spatial feature informations. Furthermore, a dilated convolution is deployed into graph convolution for capturing multi-scale contextual messages. The proposed STDGCN integrates the dilated convolution into the graph convolution, which realizes the extraction of the spatial and temporal characteristics of traffic flow data, as well as features of road occupancy. To observe the performance of the proposed model, we compare with it with four rivals. We also employ four indicators for evaluation. The experimental results show STDGCN’s effectiveness. The prediction accuracy is improved by 17% in comparison with the traditional prediction methods on various real-world traffic datasets.

Discrete Time Modeling of Wireless Power Transfer System Using LCC Compensation Topology

Xiufang Hu,Yue Wang,Shuangqing Lv,Xiaoshuai Dong,Tianjin Chen,Yongbin Jiang,Pengfan Xu 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

In recent years, wireless power transfer (WPT) technology has developed rapidly. However, conventional modeling methods for the dynamics of WPT suffer from the order increase problem and complicated derivations and expressions. In this paper, a discrete time modeling method is used for wireless power transfer systems which use magnetic resonant coupling. The proposed method aims on the dynamics of the overall WPT system, including the nonlinear inverter and rectifier. The orders of the developed models are lower than that of the generalized state space averaging method and the extended describing functions technique. Control to output voltage small-signal behaviors predicted by the discrete time model are verified by circuit simulation results.

Involvement of Social Media in Disaster Management during the Wenchuan and Ya'an Earthquakes

Li, Leah Xiufang Center for Asian Public Opinion ResearchCollaborat 2014 Asian journal for public opinion research Vol.1 No.4

Social media is being increasingly utilized in disaster relief work to identify safety issues, locate displaced-victims, and seek or provide support for those who need help. The presence of social media in disaster management has changed significantly in recent years, as it was not prevalent in the 2008 Wenchuan earthquake, but had become a powerful force in the 2013 Ya'an earthquake. This paper discusses the development of social media in disaster management via making a comparison between how it functioned in the two earthquakes. It examines the following aspects: who are the stakeholders that use social media in the earthquake management; how do they adopt this means in response to the earthquakes; and what are the outcomes of adopting social media with regards to public engagement and collaboration in an emergency event. As Sina Weibo acts as the equivalent of China's Twitter, the methodology relies on an analysis of posts in Weibo. The outcomes primarily show that: (1) authorities, celebrities and the public actively adopted social media for the purpose of information dissemination and resource mobilization; and (2) social media users are both content consumers and content generators in the times of earthquakes. The study concludes that social media as a backchannel communication tool is helpful for government institutions, corporations, and nonprofit organizations to build relationships with their stakeholders in the disaster management cycle. The result will interest academics and emergency management practitioners who are concerned with improving disaster communication.

Microstructure and Thermal Stability of a Ni-Cr-Co-Ti-V-Al High-Entropy Alloy Coating by Laser Surface Alloying

Zhaobing Cai,Xiufang Cui,Guo Jin,Zhe Liu,Wei Zheng,Yang Li,Liquan Wang 대한금속·재료학회 2017 METALS AND MATERIALS International Vol.23 No.5

A Ni-Cr-Co-Ti-V-Al high-entropy alloy (HEA) coating with a BCC phase and (Ni, Co)Ti2 compounds was synthesizedsuccessfully by laser surface alloying on a Ti-6Al-4V substrate. The microstructure of as-synthesizedcoatings is typical, namely, the microstructure from the coating to the substrate changes from equiaxed grains tocolumnar grains. After remaining at 900 °C for 8 h, the constituent phases remain unchanged. However, owing tothe unceasing dissolution of the Ti element, the lattice parameter of the BCC HEA phase changes from 3.06 Å to3.16 Å. The thermoanalysis results show that the oxidation film on the Ni-Cr-Co-Ti-V-Al HEA coating is mainlycomposed of TiO2, V2O5, and NiO. The oxidation resistance of this HEA coating may be due to the existence ofNiO and the alloying elements Al, Cr, and Co; the oxidation phenomenon should be responsible for the massincrease in the thermogravimetry process. The differential scanning calorimetry and the dynamic differential scanningcalorimetry curves show that the synthesized HEA coating is stable below 1005 °C.

A Pilot Study of Clinical Evaluation and Formation Mechanism of Irritable Bowel Syndrome-like Symptoms in Inflammatory Bowel Disease Patients in Remission

( Haiyang Wang ),( Xiaojing Zhao ),( Xiufang Cui ),( Meifeng Wang ),( Chunhua Jiao ),( Jiajia Li ),( Yan Yang ),( Yi Li ),( Hongjie Zhang ) 대한소화기기능성질환·운동학회 2021 Journal of Neurogastroenterology and Motility (JNM Vol.27 No.4

Background/Aims Some inflammatory bowel disease (IBD) patients in remission suffer from irritable bowel syndrome (IBS)-like symptoms (IBD-IBS). The pathogenesis has not yet been elucidated. The study aim is to evaluate relationships among quality of life (QOL), psychological status, and visceral sensitivity, and explore the formation mechanism of IBD-IBS. Methods Forty-seven patients with Crohn’s disease in remission, 24 ulcerative colitis in remission, 26 IBS, and 20 healthy controls were included in the study. The abdominal pain, QOL, anxiety, and depression were evaluated through questionnaires. Visceral sensitivity was measured by rectal balloon distension. The serum levels of 5-hydroxytryptamine (5-HT) and nerve growth factor (NGF) were measured by enzyme-linked immunosorbent assay. The expressions of tryptase, 5-HT, NGF, and related receptors in colonic tissues were detected by immunohistochemistry and western blot. Results Prevalence of IBS-like symptoms in Crohn’s disease and ulcerative colitis patients in clinical remission was 29.8% and 50.0%, respectively. The QOL was lower, the anxiety/depression scores were higher in IBD-IBS patients than those without IBS-like symptoms. Additionally, patients with IBD-IBS existed visceral hypersensitivity. Besides, abdominal pain was associated with poor QOL, visceral hypersensitivity, anxiety, and depression in IBD-IBS patients. The number of mast cells (MCs) and expressions of 5-HT, NGF, and related receptors were higher in IBD-IBS patients than those with no such symptoms. The serum levels of 5-HT and NGF positively correlated with abdominal pain and visceral hypersensitivity. Conclusion IBD-IBS patients may have low QOL and psychological abnormalities, as wells as visceral hypersensitivity which may be related to increased 5-HT and NGF levels released from activated mast cells. (J Neurogastroenterol Motil 2021;27:612-625)

Zirconia-supported niobia catalyzed formation of propanol from 1,2-propanediol via dehydration and consecutive hydrogen transfer

Gongming Peng,Xicheng Wang,Xiufang Chen,Yijun Jiang,Xindong Mu 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

Vapor-phase catalytic dehydration of 1,2-propanediol was investigated over Zirconia-supported niobia catalysts. The catalysts exhibit selectivity favoring propanol (approximately 39%) at 85.0% 1,2-propanediol conversion at 290 8C under 1 atm N2. The ZrNbO catalysts were analyzed by various techniques; the results indicated that the active sites were weak Brønsted acid sites. A dehydration and hydrogen transfer mechanism was also proposed. 2013 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V.

Real-time Evaluation Mechanism Based on Double Evidence Classification of User Behavior

Jiale Zhang,Guiling Zhang,Xiufang Zhang 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.12

With the development of trusted network, the research of trusted evaluation mechanism of user behavior is a hotpot in the network security. In order to solve the problems of subjectivity, limitations and static in traditional trusted network user behavior evaluation models, we have to find a real-time and dynamic evaluation method for user behavior. In this paper, the authors construct a real-time evaluation mechanism based on double evidence classification of user behavior (DEC-UB). The evaluation mechanism includes the process classification and characteristic classification of user behavior evidence, which makes the user behavior evidence of any time can be directly involved in the trust evaluation, and the evaluation result is more comprehensive and accurate. Simulation experiments have evaluated the three kinds of user behaviors based on the DEC-UB, and compared them with the other two kinds of trust evaluation methods of user behavior, the results show that the proposed methods can evaluate the user's behavior comprehensively, accurately and dynamically in complex network environments, and the results are more realistic.