A theoretical mapping model for bridge deformation and rail geometric irregularity considering interlayer nonlinear stiffness

Lei-xin Nie,Lizhong Jiang,Yulin Feng,Wang-Bao Zhou,Xiang Xiao 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.46 No.1

This paper examines a high-speed railway CRTS-Ⅱ ballastless track-bridge system. Using the stationary potential energy theory, the mapping analytical solution between the bridge deformation and the rail vertical geometric irregularity was derived. A theoretical model (TM) considering the nonlinear stiffness of interlayer components was also proposed. By comparing with finite element model results and the measured field data, the accuracy of the TM was verified. Based on the TM, the effect of bridge deformation amplitude, girder end cantilever length, and interlayer nonlinear stiffness (fastener, cement asphalt mortar layer (CA mortar layer), extruded sheet, etc.) on the rail vertical geometric irregularity were analyzed. Results show that the rail vertical deformation extremum increases with increasing bridge deformation amplitude. The girder end cantilever length has a certain influence on the rail vertical geometric irregularity. The fastener and CA mortar layer have basically the same influence on the rail deformation amplitude. The extruded sheet and shear groove influence the rail geometric irregularity significantly, and the influence is basically the same. The influence of the shear rebar and lateral block on the rail vertical geometric irregularity could be negligible.

Comparison research and phylogenetic implications of mitochondrial control regions in four soft‐shelled turtles of Trionychia (Reptilia, Testudinata)

Lei Xiong,Xiaosan Li,Xin Liu,Liuwang Nie 한국유전학회 2010 Genes & Genomics Vol.32 No.4

The mitochondrial control regions (CRs) and flanking sequences of Pelodiscus sinensis, Apalone ferox, Palea steindachneri and Carettochelys insculpta were obtained using Long‐PCR with gene‐specific primers. The CR lengths of the four species were 1843 bp, 1356 bp, 1725 bp, and 969 bp. The base composition percentages of A+T were 60.5%, 60.7%,65.7%, 64.7%, respectively. Combined with CR sequences of other three soft‐shelled turtles published in GenBank (Pelodiscus sinensis, Korea, AY962573; Dogania subplana,AF366350; Lissemys punctata, EF050073), we compared the CR structures and identified three functional domains (TAS,CD and CSB) in which conserved sequence blocks (TAS, CSB ‐F, CSB‐1, CSB‐2 and CSB‐3) were also successfully identified according to their sequence similarities to those of other turtles. The variable numbers of tandem repeats (VNTRs 1)with 50‐52 bp motif were identified at 5'‐end of CR among the five soft‐shelled turtles P. sinensis (China), P. sinensis (Korea), A. ferox, P. steindachneri, D. subplana. The copy number of the VNTRs varied from 5 to 15. VNTRs 2 with 2‐11 bp motif were identified in the 3'‐ end of CR among all of the six soft‐shelled turtles with variable number of motifs from 4 to 29. Moreover, VNTRs 3 with 6 bp motif were identified between CSB‐1 and CSB‐2 of CR both in P. sinensis (China) and P. sinensis (Korea), in which the number of motifs varied from 19 to 29. The types and distribution of VNTRs of the six soft‐shelled turtles were also discussed. With Alligator mississippiensis as an outgroup, combined with the CR sequences (excluding VNTRs) of other five turtles which were published in GenBank, the molecular phylogenetic trees were constructed using PAUP 4.0b10 and MrBayes ver. 3.0. The results strongly supported the monophyly of Carretochelyidae and Carettochelyidae as sister group to an assemblage of Cryptodira. Our research suggested that the earliest phylogenetic tree splits into three separated basal branches; the Pelomedusidira (Pelomedusa subrufa), the Carettochelyidae (C. insculpta), and an assemblage of Cryptodira and the C. insculpta that might be a representation of distinctive suborder.

Shorter Distance Between the Nodule and Capsule has Greater Risk of Cervical Lymph Node Metastasis in Papillary Thyroid Carcinoma

Wang, Qiu-Cheng,Cheng, Wen,Wen, Xin,Li, Jie-Bing,Jing, Hui,Nie, Chun-Lei Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.2

Background: The purpose of this study was to assess the relationship between different sonographic features of papillary thyroid carcinoma (PTC) on high-frequency ultrasound and cervical lymph node metastasis (CLNM). Materials and Methods: We enrolled 548 patients who underwent initial surgery for PTC between May 2011 and December 2012 in our hospital at diagnosis. The sonographic features of 513 PTC nodules in 513 eligible patients, who had single PTC nodules in their thyroid glands, were retrospectively investigated. All patients with a suspect malignant nodule (d<0.5cm) among multiple nodules were initially diagnosed by fine-needle aspiration biopsy (FNAB) to ascertain if the suspect nodule was PTC. The final diagnosis of all the thyroid nodules and existence of CLNM were based on postoperative pathology. Patients were divided into two groups: a positive group with CLNM (224 nodules) and a negative group without CLNM (289 nodules). The following factors were investigated: gender, age, echogenicity, echotexture, size, shape, location, margin, contour, calcification morphology, distance between the nodule and pre- or post-border of the thyroid capsule, vascularity and the differences between the two groups. Results: Correlation analysis showed that shorter distances between the nodule and pre- or postborder of thyroid capsule resulted in greater risk of CLNM (Spearman correlation coefficient=-0.22, p<0.0001). The significant factors in multivariate analysis were age<45yrs, larger size (d>1cm), "wider than tall" shape, extrathyroid extension and mixed flow (internal and peripheral) (p<0.05, OR=0.406, 2.093, 0.461, 1.610, 1.322). Conclusions: Significant sonographic features of PTC nodules in preoperative high-frequency ultrasound are crucial for predicting CLNM.

Distortional Buckling Analysis of I-Steel Concrete Composite Beams Subjected to Hogging Moment

Lili Liu,Lizhong Jiang,Chun-dan Li,Wang-Bao Zhou,Lei-xin Nie 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.3

Bending-torsional distortion buckling is one of the most critical buckling modes of steel–concrete composite beams when they are working under hogging moment. The rotational and lateral restraint stiff ness provided by the steel web to the steel bottom fl ange are the key factors to determine this form of buckling. Firstly, the formula for solving the elastic rotational restraint stiff ness of the composite fl ange of steel beam upper fl ange and concrete slab to the steel web is derived. Then, the equivalent lateral and rotational restraint stiff ness of the steel bottom fl ange subjected to hogging moment are thoroughly studied. Considering the rotation restraint eff ect of the composite fl ange, this paper provides the calculation formula for the critical bending moment of I-steel concrete composite beams (I-SCCB) under hogging moment. Fifteen examples are considered to calculate the critical bending moment of the I-SCCB under hogging moment with the simplifi ed analytical method introduced in this paper. The results are compared with the ones derived by ANSYS numerical analyses and relevant research of other scholars. The infl uence of the arrangement of the shear studs on the critical bending moment of the I-SCCB is investigated. It is concluded that the results given by the simplifi ed analytical method are in good agreement with the ones obtained by the ANSYS fi nite element numerical method. Both methods show that the critical load of the distortional buckling of the I-SCCB under hogging moment is less aff ected by the member’s length. The critical bending moment of distortional buckling of the I-SCCB signifi cantly increases with the presence of shear studs. However, once shear studs are used, it tends to be stable with the increase of equivalent restrained torsional rotational stiff ness at the top edge of the steel web.