Exact and approximate solutions for free vibrations of continuous partialinteraction composite beams

Kai Q. Sun,Nan Zhang,Qun X. Zhu,Xiao Liu 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.44 No.4

An exact dynamic analytical method for free vibrations of continuous partial-interaction composite beams is proposed based on the Timoshenko beam theory. The main advantage of this method is that the independent shear deformations and rotary inertia of sub-beams are considered, which is more in line with the reality. Therefore, the accuracy of eigenfrequencies obtained by this method is significantly improved, especially for higher order modes, compared to the existing methods where the rotary angles of both sub-beams are assumed to be equal irrespective of the differences in the shear stiffness of each sub-beam. Furthermore, the solutions obtained by the proposed method are exact owing to no introduction of approximated displacement and force fields in the derivation. In addition, an exact analytical solution for the case of simply supported is obtained. Based on this, an approximate expression for the fundamental frequency of continuous partial-interaction composite beams is also proposed, which is useful for practical engineering applications. Finally, the practicability and effectiveness of the proposed method and the approximate expression are explored using numerical and experimental examples; The influence factors including the interfacial interaction, shear modulus ratio, span-to-depth ratio, and side-to-main span length ratio on the eigenfrequencies are presented and discussed in detail.

Experimental research on seismic behavior of SRC-RC transfer columns

Kai Wu,Jianyang Xue,Yang Nan,Hongtie Zhao 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.1

It was found that the lateral stiffness changes obvious at the transfer position of the section configuration from SRC to RC. This particular behavior leads to that the transfer columns become as the important elements in SRC-RC hybrid structures. A comprehensive study was conducted to investigate the seismic behavior of SRC-RC transfer columns based on a low cyclic loading test of 16 transfer columns compared with 1 RC column. Test results shows three failure modes for transfer columns, which are shear failure, bond failure and bend failure. Its seismic behavior was completely analyzed about the failure mode, hysteretic and skeleton curves, bearing capacity deformation ability, stiffness degradation and energy dissipation. It is further determined that displacement ductility coefficient of transfer columns changes from 1.97 to 5.99. The stiffness of transfer columns are at the interval of SRC and RC, and hence transfer columns can play the role of transition from SRC to RC. All specimens show similar discipline of stiffness degradation and the process can be divided into three parts. Some specimens of transfer column lose bearing capacity swiftly after shear cracking and showed weak energy dissipation ability, but the others show better ability of energy dissipation than RC column.

An equivalent single-layer theory for free vibration analysis of steel-concrete composite beams

Kai Q. Sun,Nan Zhang,Xiao Liu,Yan X. Tao 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.38 No.3

An equivalent single-layer theory (EST) is put forward for analyzing free vibrations of steel-concrete composite beams (SCCB) based on a higher-order beam theory. In the EST, the effect of partial interaction between sub-beams and the transverse shear deformation are taken into account. After using the interlaminar shear force continuity condition and the shear stress free conditions at the top and bottom surface, the displacement function of the EST does not contain the first derivatives of transverse displacement. Therefore, the C0 interpolation functions are just demanded during its finite element implementation. Finally, the EST is validated by comparing the results of two simply-supported steel-concrete composite beams which are tested in laboratory and calculated by ANSYS software. Then, the influencing factors for free vibrations of SCCB are analyzed, such as, different boundary conditions, depth to span ratio, high-order shear terms, and interfacial shear connector stiffness.

Analysis on Extension Length of Shape Steel in Transfer Columns of SRC–RC Hybrid Structures

Kai Wu,Jianyang Xue,Yang Nan,Hong-tie Zhao 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.3

Seismic performance of SRC–RC transfer column was analyzed based on the experiment of 16 transfer columns specimens under low cyclic reversed loading, which mainly focus on the extension length of shape steel. Analysis of ductility, bearing capacity, energy dissipation capacity and degeneration ratio of strength were completed. Displacement ductility promotes at fi rst and then reduces with increasing of extension length of shape steel, reaching the peak value when extension length gets close to three fi fths of column height. Extension length of shape steel has little eff ect on bearing capacity, while energy dissipation capacity of transfer columns is infl uenced by many factors. Three fi fths of column height is the rational extension length of shape steel, of which specimens have advanced in energy dissipation, good stability of stiff ness and strength. The bond performance between concrete and shape steel decreases with the increasing of extension length of shape steel, and hence the stability of strength decreases. Minimum extension length of shape steel was confi rmed and the calculation method was proposed, which is mainly used to ensure the bend yielding of shape steel at bottom section. Moment at the truncation section leads to pull-out eff ect of steel bars, which enhances with increasing of the moment and section ratio of shape steel. Contrafl exure point is at three fi fths of column height. If the shape steel extends to contrafl exure point, moment of steel truncation section will reach minimum. So the reduce the concrete damage with better deformation ability and mechanical behavior of transfer column.

Duration-Related Variations in Archaeal Communities after a Change from Upland Fields to Paddy Fields

( Nan Jiang ),( Kai Wei ),( Lijun Chen ),( Rui Chen ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.5

Archaea substantially contribute to global geochemical cycling and energy cycling and are impacted by land-use change. However, the response of archaeal communities to a change from upland field to paddy field has been poorly characterized. Here, soil samples were collected at two depths (0-20 cm and 20-40 cm) from one upland field and six paddy fields that were established on former upland fields at different times (1, 5, 10, 20, 30, and 40 years before the study). Barcoded pyrosequencing was employed to assess the archaeal communities from the samples at taxonomic resolutions from phylum to genus levels. The total archaeal operational taxonomic unit (OTU) richness showed a significant positive correlation with the land-use change duration. Two phyla, Euryarchaeota and Crenarchaeota, were recorded throughout the study. Both the relative abundance and OTU richness of Euryarchaeota increased at both depths but increased more steadily at the subsurface rather than at the surface. However, these data of Crenarchaeota were the opposite. Additionally, the archaeal composition exhibited a significant relationship with C/N ratios, total phosphorus, soil pH, Olsen phosphorus, and the land-use change duration at several taxonomic resolutions. Our results emphasize that after a change from upland fields to paddy fields, the archaeal diversity and composition changed, and the duration is an important factor in addition to the soil chemical properties.

Gallbladder Cancer: a Subtype of Biliary Tract Cancer Which is a Current Challenge in China

Qu, Kai,Liu, Si-Nan,Chang, Hu-Lin,Liu, Chang,Xu, Xin-Sen,Wang, Rui-Tao,Zhou, Lei,Tian, Feng,Wei, Ji-Chao,Tai, Ming-Hui,Meng, Fan-Di Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.4

Biliary tract cancers, broadly described as malignancies that arise from the biliary tract epithelia, are usually divided into two major clinical phenotypes: cholangiocarcinoma and gallbladder cancer, differing in etiopathogenesis, risk factors, and perhaps molecular and genetic signatures. Atypical symptoms and lack of tumor biomarkers make it difficult to diagnose in early stages. At the time of presentation, few patients are candidates for potentially curative surgical resection. We here assessed and compared features of a total of 150 cases divided into extra- and intrahepatic cholangiocarcinomas and gallbladder cancers (GBC). Althought there were no significant differences in serum tumour marker levels, GBC patients had the poorest prognosis. Furthermore, gallbladder cancer respond poorly to chemotherapy or radiation therapy and approximately half of untreated patients died within 10 months. Therefore, treatment for patients with gallbladder cancer is still in challenge. Outcomes and survival of these patients had improved little over the past three decades - a period in which new successful treatments have greatly contributed to the prolonged patient survival for many other cancers.

The Research of the Oil Drilling Materials Information Management System Based on RFID

Bai Kai,Xia Hong-Nan,Jin Guo-Xing,Wang Hua-Bing 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.10

In the present drilling materials supplies management informationization level is low, which lead to low efficiency of management in the Chinese oil enterprises. This paper presents an effective solution combined with RFID and web technology for oil enterprise information service platform system, and studies several key technologies in the design. The system has taken the advantages of RFID and web services in the practical application process, the enterprises can use this RFID solution to enhance the logistics management efficiency in the oil-drilling materials supplies. At the end of the paper we proposed technical barriers is one of the reasons for RFID popularization.

Sulforaphane Inhibits TNF-α-Induced Adhesion Molecule Expression Through the Rho A/ROCK/NF-κB Signaling Pathway

Chi-Nan Hung,Hui-Pei Huang,Chau-Jong Wang,Kai-Li Liu,Chong-Kuei Lii 한국식품영양과학회 2014 Journal of medicinal food Vol.17 No.10

Endothelial dysfunction is an early indicator of cardiovascular diseases. Increased stimulation of tumor necrosis factor-a (TNF-a) triggers the inflammatory mediator secretion of endothelial cells, leading to atherosclerotic risk. In this study, we investigated whether sulforaphane (SFN) affected the expression of intracellular adhesion molecule-1 (ICAM-1) in TNF-a-induced ECV 304 endothelial cells. Our data showed that SFN attenuated TNF-a-induced expression of ICAM-1 in ECV 304 cells. Pretreatment of ECV 304 cells with SFN inhibited dose-dependently the secretion of proinflammatory cytokines, such as interleukin (IL)-1b, IL-6, and IL-8. SFN inhibited TNF-a-induced nuclear factor-jB (NF-jB) DNA binding activity. Furthermore, SFN decreased TNF-a-mediated phosphorylation of IjB kinase (IKK) and IjBa, Rho A, ROCK, ERK1/2, and plasminogen activator inhibitor-1 (PAI-1) levels. Collectively, SFN inhibited the NF-jB DNA binding activity and downregulated the TNF-a-mediated induction of ICAM-1 in endothelial cells by inhibiting the Rho A/ROCK/NF-jB signaling pathway, suggesting the beneficial effects of SFN on suppression of inflammation within the atherosclerotic lesion.

Prognosis and Management for Gallbladder Cancer with Hepatic Invasion: Long-term Results of 139 Patients from a Single Center in China

Qu, Kai,Chang, Hu-Lin,Liu, Si-Nan,Liu, Chang,Xu, Xin-Sen,Wang, Rui-Tao,Zhou, Lei,Tian, Feng,Wei, Ji-Chao,Tai, Ming-Hui,Meng, Fan-Di Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.3

Objective: To improve the diagnosis of primary gallbladder carcinoma (GBC) with/without hepatic metastases by analyzing our experience of different GBC treatment in our patients. Methods: A retrospective study was carried out to analyze the clinical data of the 139 patients with GBC who underwent hepatic resection in our unit from January 2003 to December 2007. Patients were divided into two groups according to whether they demonstrated hepatic invasion. Tumor presentation, surgical modes, and prognosis of each patient were retrospectively reviewed. Kaplan-Meier curves and log-rank tests were employed to compare the survival rates of those patients undergoing different surgical procedures. Results: Of the 139 patients, 46 were men and 93 were women with the male to female ratio of 1:2.0. Their ages were ranged from 35 to 86 years with a mean age of $62.8{\pm}10.4$ years. There were 73 patients complicated with hepatic invasion (group A), and no hepatic invasion occurred in the other 66 patients (group B). Compared with the group B, the patients with hepatic invasion suffered lower differentiation of tumor (p=0.000), more advanced Nevin staging (p=0.008) and poorer prognosis (p=0.013). Radical resection were more frequently performed in group B (75.76%) than in group A (45.20%) with better outcomes (p=0.000). Conclusion: GBC patients complicated with hepatic invasion had poorer prognosis than those without invasion in long-term follow-ups. Radical resection might result in a satisfied prognosis in patients without hepatic invasion, but appears less favorable than palliative resection in those who were complicated with hepatic invasion.

A Further Result Related to a Conjecture of R. Brück

Li, Nan,Yang, Lianzhong,Liu, Kai Department of Mathematics 2016 Kyungpook mathematical journal Vol.56 No.2

In this paper, we investigate the uniqueness problem of a meromorphic function sharing one small function with its differential polynomial, and give a result which is related to a conjecture of R. $Br{\ddot{u}}ck$.