After-fracture behaviour of steel-concrete composite twin I-girder bridges: An experimental study

Weiwei Lin 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.42 No.1

To simplify the design and reduce the construction cost of traditional multi-girder structural systems, twin I-girder structures are widely used in many countries in recent years. Due to the concern on post-fracture redundancy, however, twin girder bridges are currently classified as fracture critical structures in AASHTO specifications for highway bridges. To investigate the after-fracture behavior of such structures, a composite steel and concrete twin girder specimen was built and an artificial fracture through the web and the bottom flange was created on one main girder. The static loading test was performed to investigate its mechanical performance after a severe fracture occurred on the main girder. Applied load and vertical displacement curves, and the applied load versus strain relationships at key sections were measured. To investigate the load distribution and transfer capacities between two steel girders, the normal strain development on crossbeams was also measured during the loading test. In addition, both shear and normal strains of studs were also measured in the loading test to explore the behavior of shear connectors in such bridges. The functions and structural performance of structural members and possible load transfer paths after main girder fractures in such bridges were also discussed. The test results indicate in this study that a typical twin I-girder can resist a general fracture on one of its two main girders. The presented results can provide references for postfracture performance and optimization for the design of twin I-girder bridges and similar structures.

A quantitative assessment method of network information security vulnerability detection risk based on the meta feature system of network security data

( Weiwei Lin ),( Chaofan Yang ),( Zeqing Zhang ),( Xingsi Xue ),( Reiko Haga ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.12

Because the traditional network information security vulnerability risk assessment method does not set the weight, it is easy for security personnel to fail to evaluate the value of information security vulnerability risk according to the calculation value of network centrality, resulting in poor evaluation effect. Therefore, based on the network security data element feature system, this study designed a quantitative assessment method of network information security vulnerability detection risk under single transmission state. In the case of single transmission state, the multi-dimensional analysis of network information security vulnerability is carried out by using the analysis model. On this basis, the weight is set, and the intrinsic attribute value of information security vulnerability is quantified by using the qualitative method. In order to comprehensively evaluate information security vulnerability, the efficacy coefficient method is used to transform information security vulnerability associated risk, and the information security vulnerability risk value is obtained, so as to realize the quantitative evaluation of network information security vulnerability detection under single transmission state. The calculated values of network centrality of the traditional method and the proposed method are tested respectively, and the evaluation of the two methods is evaluated according to the calculated results. The experimental results show that the proposed method can be used to calculate the network centrality value in the complex information security vulnerability space network, and the output evaluation result has a high signal-to-noise ratio, and the evaluation effect is obviously better than the traditional method.

Numerical Study on Horizontally Curved Steel-Concrete Composite Beams Subjected to Hogging Moment

Weiwei Lin,Teruhiko Yoda 한국강구조학회 2014 International Journal of Steel Structures Vol.14 No.3

The horizontally curved continuous composite steel-concrete beams, for instance, curved continuous composite bridges, haveexcellent qualities, such as quick construction, good seismic performance, saving construction formwork and convenience inspatial arrangement etc. At present, the application research of this kind of structures is becoming more of a concern, but veryfew studies have been conducted to study the mechanical performance of composite beams subjected to combined hogging(negative) bending and torsion. The purpose of the present study is to investigate the effects of curvatures on both elastic andinelastic behaviours of curved continuous steel-concrete composite beams in the interior support regions. Based on theexperimental observations in a straight composite beam, a three-dimensional FE model capable of analysing the compositebeams subjected to negative bending moment is built. Further numerical studies on curved composite beams with differentcurvatures are performed in this study. Strength and load carrying capacity, sectional strain distribution and movement ofcomposite neutral axis before and after cracking, as well as the strain results of longitudinal reinforcing bars are investigated. Besides, the interaction equation for ultimate bending and torsional moments is proposed.

Analysis, Design and Construction of Curved Composite Girder Bridges: State-of-the-Art

Weiwei Lin,Teruhiko Yoda 한국강구조학회 2010 International Journal of Steel Structures Vol.10 No.3

The horizontally curved composite girder bridges have excellent properties, such as quick construction, good seismic performance, saving construction formwork and convenience in spatial arrangement.etc, which have greatly promoted the application of such bridges. The objective of this paper is to provide and summarize important references related to the analysis,design and construction of curved composite girder bridges. Subjects discussed in this review include (1) different curved girder bridge configurations and their applied range; (2) current specifications; (3) construction issues; (4) design methods; (5) analytical methods; (6) load distribution; (7) torsional behavior; (8) warping stresses; (9) stability; (10) ultimate load-carrying capacity; (11)dynamic and seismic response; (12) loading test; (13) long-term behavior; and (14) design details. The literature survey presented herein mainly focuses on papers written in English, Japanese and Chinese in relation to curved composite girders.

Numerical Study on Post-Fracture Redundancy of the Two-girder Steel-Concrete Composite Highway Bridges

Weiwei Lin,Teruhiko Yoda,Yoji Kumagai,Takeshi Saigyo 한국강구조학회 2013 International Journal of Steel Structures Vol.13 No.4

As the Japan bridge inventory ages and traffic volumes increase, the government is spending more on maintaining theirexisting structures to extend the service life of the current bridge inventory. This includes two-girder bridges that are classifiedas fracture critical and non-redundant. Owing to the increased inspection costs associated with these fracture-critical bridges,there is a need to evaluate alternate load paths and to implement retrofit methods on existing bridge structures to avoid bridgereplacement. In this paper, fracture redundancy of the two-girder bridge is investigated through a case study for a three-spancontinuous twin I-girder bridge. The finite element analysis is carried out to evaluate the load-carrying capacity after fractureof a girder of the two-girder bridge. Damage of studs near the moment contra-flexure regions are also considered in this study. Spacing between the transverse beams is discussed as possible techniques to improve redundancy and reduce the fracturepotential of two-girder bridge structures. The concrete slab is indicated to be a significant member for guarantying theredundancy of the two-girder steel-concrete composite bridges.

Long-term Survivals, Toxicities and the Role of Chemotherapy in Early-Stage Nasopharyngeal Carcinoma Patients Treated with Intensity-modulated Radiation Therapy: A Retrospective Study with 15-year Follow-up

Lin Wang,Jingjing Miao,Huageng Huang,Boyu Chen,Xiao Xiao,Manyi Zhu,Yingshan Liang,Weiwei Xiao,Shaomin Huang,Yinglin Peng,Xiaowu Deng,Xing Lv,Weixiong Xia,Yanqun Xiang,Xiang Guo,Fei Han,Chong Zhao 대한암학회 2022 Cancer Research and Treatment Vol.54 No.1

Purpose This study was aimed to investigate long-term survivals and toxicities of early-stage nasopharyngeal carcinoma (NPC) in endemic area, evaluating the role of chemotherapy in stage II patients. Materials and Methods Totally 187 patients with newly diagnosed NPC and restaged American Joint Committee on Cancer/ International Union Against Cancer 8th T1-2N0-1M0 were retrospectively recruited. All received intensity-modulated radiotherapy (IMRT)±chemotherapy (CT) from 2001 to 2010. Results With 15.7-year median follow-up, 10-year locoregional recurrence-free survival, distant metastasis-free survival (DMFS), disease-specific survival (DSS), and overall survival (OS) were 93.3%, 93.5%, 92.9% and 88.2%, respectively. Multivariable analyses showed cervical lymph nodes positive and pre-treatment prognostic nutritional index ≥ 52.0 could independently predict DMFS (p=0.036 and p=0.011), DSS (p=0.014 and p=0.026), and OS (p=0.002 and p < 0.001); Charlson comorbidity index < 3 points could predict DSS (p=0.011); age > 45 years (p=0.002) and pre-treatment lactate dehydrogenase ≥ 240 U/L (p < 0.001) predicted OS. No grade 4 late toxicity happened; grade 3 late toxicities included subcutaneous fibrosis (4.3%), deafness or otitis (4.8%), skin dystrophy (2.1%), and xerostomia (1.1%). No differences on survivals were shown between IMRT+CT vs. IMRT alone in stage II patients, even in T2N1M0 (p > 0.05). Unsurprising, patients in IMRT+CT had more acute gastrointestinal reaction, myelosuppression, mucositis, late ear toxicity, and cranial nerve injury (all p < 0.05) than IMRT alone group. Conclusion Superior tumor control and satisfying long-term outcomes could be achieved with IMRT in early-stage NPC with mild late toxicities. As CT would bring more toxicities, it should be carefully performed to stage II patients.

Amplification at 1400–1450 nm of the Large-Core Nd-Doped Fiber by White LED Pumping

Lin Htein,Weiwei Fan,Watekar, P. R.,Won-Taek Han IEEE 2013 Photonics Technology Letters Vol.25 No.11

<P>A novel cost-effective fiber amplifier operating over 1400-1450 nm is developed based on pumping of a large-core Nd-doped fiber with a high-power white light-emitting diode (LED). An optical gain of 6 dB at 1400 nm is obtained by simultaneously exciting the multiple absorption bands in the visible wavelength of the Nd-doped fiber.</P>

Amplification by white light-emitting diode pumping of large-core Er-doped fiber with 12 dB gain.

Htein, Lin,Fan, Weiwei,Watekar, Pramod R,Han, Won-Taek Optical Society of America 2012 Optics letters Vol.37 No.23

<P>We have developed a cost-effective, high-capacity Er-doped fiber amplifier based on the high-power white LED and a large-core Er-doped fiber. Er ions of the fiber with absorption bands at 453, 488, 523, and 654 nm were simultaneously excited by LED pumping and amplification with optical gain over 12 dB at 1550 nm was obtained.</P>

A Fuzzy Algorithm of Peer Selection for P2P Streaming Media System Based on Gossip Transmission Protocol

Xunli Fan,Weiwei Zhang,Lin Guan 보안공학연구지원센터 2009 International Journal of Multimedia and Ubiquitous Vol.4 No.1

The traditional Gossip protocol selects the neighbor nodes randomly. It does not consider the factors, such as the capacities of network transmission and node storage, which affect the network performance. It further causes the drawback of successful search ratio relatively lower, and also network transmission payloads have the characteristics of randomness. In this paper, to overcome those drawbacks of traditional Gossip protocol, a neighbor node selection algorithm has been studied, and various factors that may affect the neighbor node selection have been analyzed in P2P networks. A new neighbor node selection policy has been proposed, which is a reliable Gossip message transmission Protocol based on fuzzy theory. Empirical simulation experiments with various data analysis have demonstrated the improvement of efficiency of the proposed strategy on node selection and correctness of the proposed algorithm in P2P networks.

Synthesis of CdS, ZnS, and CdS/ZnS Core/Shell Nanocrystals Using Dodecanethiol

Jinzhong Niu,Weiwei Xu,Huaibin Shen,Sen Li,Hongzhe Wang,Lin Song Li 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.2

We report a new route to synthesize high quality zinc blende CdS and ZnS nanocrystals in noncoordinating solvent 1-octadecene, using dodecanethiol (DDT) molecules as both the sulfur source and surface capping ligands. Different reaction temperatures and Cd(Zn)/DDT molar ratios were tested to optimize the synthesis conditions. Absorption photoluminescence (PL) spectroscopy, Fourier transform infrared (FTIR) spectroscopy,X-ray diffraction (XRD) pattern, and transmission electron microscopy (TEM) were used to characterize assynthesized nanocrystals. The narrow half width at the half-maximum on the long wavelength side of the firstexcitonic absorption peak and TEM images demonstrated nearly monodisperse size distributions of asprepared CdS, ZnS, and CdS/ZnS core/shell nanocrystals. Only trap emissions of the nanocrystals were detected when the amount of DDT was excessive, this came from the strong quenching effect of thiol groups on the nanocrystal surfaces. After overcoating with ZnS shells, band-gap emissions of CdS nanocrystals were partially recovered.