Analytical Behavior of Eccentrically Loaded Concrete Encased Steel Columns Subjected to Standard Fire including Cooling Phase

Er-Feng Du,Gan-Ping Shu,Xiao-Yong Mao 한국강구조학회 2013 International Journal of Steel Structures Vol.13 No.1

A nonlinear 3-D finite element analysis (FEA) model was developed to predict the behavior of eccentrically loaded concrete encased steel (CES) columns subjected to ISO-834 standard fire including heating and cooling phases. The finite element model has been validated against published tests conducted at elevated temperatures. Comparisons between the predicted results and the test results show that this model can accurately predict the behavior of CES columns under fire. The FEA model was then used to investigate the typical temperature-time curve and mid-height lateral deformation-time curve of eccentric compression CES columns in a complete loading history including initial loading, heating and cooling. It is shown that the temperature delay is obvious at the inner layers of concrete. The fire resistance of a CES column should be checked for the full process of fire exposure until temperatures everywhere in the column start to decrease. The lateral deformation of the column still gradually increases during the cooling phase and the column may fail during that phase. There is a large residual deformation after the fire exposure. Furthermore, the variables that influence the behavior of the CES columns under fire were investigated in parametric studies. It is found that the main parameters which influence the lateral deformation-time curve of the column during the full process of fire exposure are load ratio, slenderness ratio, duration time, depth to width ratio and steel ratio, and the main parameters which influence the residual deformation ratio of the column after fire are load ratio, duration time, cross-sectional depth and steel ratio.

DEPTOR Expression Negatively Correlates with mTORC1 Activity and Tumor Progression in Colorectal Cancer

Lai, Er-Yong,Chen, Zhen-Guo,Zhou, Xuan,Fan, Xiao-Rong,Wang, Hua,Lai, Ping-Lin,Su, Yong-Chun,Zhang, Bai-Yu,Bai, Xiao-Chun,Li, Yun-Feng Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.11

The mammalian target of rapamycin (mTOR) signaling pathway is upregulated in the pathogenesis of many cancers, including colorectal cancer (CRC). DEPTOR is an mTOR inhibitor whose expression is negatively regulated by mTOR. However, the role of DEPTOR in the development of CRC is not known. The aim of this study was to investigate the expression of DEPTOR and mTORC1 activity (P-S6) in a subset of CRC patients and determine their relation to tumor differentiation, invasion, nodal metastasis and disease-free survival. Here, Immunohistochemical expression of P-S6 (S235/236) and DEPTOR were evaluated in 1.5 mm tumor cores from 90 CRC patients and in 90 samples of adjacent normal mucosa by tissue microarray. The expression of P-S6 (S235/236) was upregulated in CRC, with the positive rate of P-S6 (S235/236) in CRC (63.3%) significantly higher than that in control tissues (36.7%, 30%) (p<0.05). P-S6 (S235/236) also correlated with high tumor histologic grade (p=0.002), and positive nodal metastasis (p=0.002). In contrast, the expression level of DEPTOR was correlated with low tumor histological grade (p=0.006), and negative nodal metastasis (p=0.001). Interestingly, P-S6 (S235/236) expression showed a significant negative association with the expression of DEPTOR in CRC (p=0.011, R= -0.279). However, upregulation of P-S6 (S235/236) (p=0.693) and downregulation of DEPTOR (p=0.331) in CRC were not significantly associated with overall survival. Thus, we conclude that expression of DEPTOR negatively correlates with mTORC1 activity and tumor progression in CRC. DEPTOR is a potential marker for prognostic evaluation and a target for the treatment of CRC.

Human Recombinant Endostatin Combined with Cisplatin Based Doublets in Treating Patients with Advanced NSCLC and Evaluation by CT Perfusion Imaging

Zhang, Feng-Lin,Gao, Er-Yun,Shu, Rong-Bao,Wang, Hui,Zhang, Yan,Sun, Peng,Li, Min,Tang, Wei,Jiang, Bang-Qin,Chen, Shuang-Qi,Cui, Fang-Bo Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.15

Aims: To study the effectiveness of human recombinant endostatin injection (Endostar(R)) combined with cisplatin doublets in treating advanced non-small cell lung cancer (NSCLC), and to evaluate outcome by CT perfusion imaging. Methods: From April 2011 to September 2014, 76 patients with advanced NSCLC who were treated with platinum-based doublets were divided into group A (36 patients) and group B (40 patients). Endostar(R) 15mg/day was administered 4 days before chemotherapy and combined with chemotherapy from day 5 in group A, and combined with chemotherapy from the first day in Group B. Endostar(R) in the two groups was injected intravenously for 14 days. Results: Treatment effectiveness in the two groups differed with statistical significance (p<0.05). Effectiveness evaluated by CT perfusion imaging, BF, BV, MTT and PS also demonstrated significant differences (all p<0.05). Adverse reactions in the two groups did not significantly vary (p> 0.05). Conclusions: The response rate with Endostar(R) administered 4 days before chemotherapy and combined with chemotherapy from day 5 in group A was better than Endostar(R) combined with chemotherapy from the first day, and CT perfusion imaging could be a reasonable method for evaluation of patient outcomes.

Ultrafast UV Switch Based on ZnO-Ag Heterostructures

XIU-YUN AN,Feng Teng,Zhenxing Zhang,Xiaojun Pan,Jinyuan Zhou,ER-QING XIE 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.1

ZnO-silver (Ag) heterostructure nanoparticle films were prepared by spin-coating, followed by annealing at 700°C for 2 h. The films were then used as UV photodetector which show high photoresponse. The heterostructure-film device displayed an ultrafast decay time of 18 ms and a rise time of 50 ms upon ultraviolet irradiation. Additionally, the time-dependent photocurrent upon UV switching reveals a rectangularly shaped profile, rarely reported in previous literature. The highly improved photoresponse properties of ZnO-Ag heterostructure-film device could be attributed to the Schottky barrier height (SBH) and depletion width reduction from the embedded Ag nanoclusters. Compared to a pure ZnO film, both the responsivity (Rλ) and external quantum efficiency (EQE) of the ZnO-Ag heterostructure-film photodetectors were improved more than 13-fold. This research provides a promising strategy for fabricating UV-photodetectors with ultrafast response.

Parameters Effect on Predicting Fire Resistance of Ultra-high Strength Concrete Filled Protected Square Steel Tubular Columns

Xiao Lyu,Gan-Ping Shu,Er-Feng Du 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.5

Ultra-high strength concrete (UHSC) with compressive strength greater than 100 MPa at room temperature has been developed for concrete fi lled square steel tubular column for use in high-rise buildings. The fi re resistance of UHSC fi lled protected square steel tubular columns exposed to the standard ISO fi re is investigated in this paper. For this purpose, numerical heat transfer analysis and nonlinear thermal stress analysis were conducted by taking into account the existing material properties, such as the thermal and mechanical properties of UHSC and high strength steel. The numerical analyses were carried out and the results were validated against the test results in terms of heat distribution and mechanical behavior. Comparison with the test results showed a reasonable agreement with fi nite element results in terms of temperature fi eld prediction and load displacement behavior during the fi re. Finally, based on the validated fi nite element model, the eff ects of fi re protection thickness, load ratio, the strengths of concrete and steel, steel contribution ratio, and relative slenderness ratio on the fi re resistance of UHSC fi lled square steel tubular columns were carried out and discussed.

A Study of Urodynamic Parameters at Different Bladder Filling Stages for Predicting Upper Urinary Tract Dilatation

Lei Lyu,Ya Xiong Yao,Er Peng Liu,Yan Ping Zhang,Hui Jie Hu,Feng Ping Ji,Qing Song Pu,Xing Huan Yang,Qing Wei Wang,Yan Wang,Jian Guo Wen 대한배뇨장애요실금학회 2022 International Neurourology Journal Vol.26 No.1

Purpose: To identify more accurate predictors of upper urinary tract dilatation (UUTD) in neurogenic bladder (NB) children, we studied the relationship among urodynamic parameters at different bladder filling stages, detrusor leak point pressure (DLPP) and UUTD. Methods: A total of 158 children (3–16 years) with NB were included and then divided into 2 groups according to whether their NB diagnosis was complicated with UUTD: the UUTD group (39 patients) and those without UUTD group (control group, 119 patients). The bladder filling phase was divided into 3 equal parts: the early, middle, and end filling stages. The bladder compliance (BC) and detrusor pressure (△Pdet) at each phase and DLPP at the end filling stage were recorded. Results: A BC<8 mL/cm H2O both in the middle and end stages is more specific than a BC<9 mL/cm H2O in the end stage (72%, 73%, vs. 66%), and △Pdet >8 cm H2O in the early stage, 20 cm H2O in the middle stage and 25 cm H2O in the end stage are more sensitive than △Pdet >40 cm H2O in the end stage (82%, 85%, 85%, vs. 49%). A DLPP cutoff value of 20 cm H2O showed higher sensitivity for predicting UUTD than 40 cm H2O. Conclusions: Low BC and a high △Pdet in the middle and end filling stages are more accurate factors than classic indicators for predicting UUTD. In addition, a DLPP value of >20 cm H2O in the end bladder filling stage shows high sensitivity.

Buckling analysis of elastically-restrained steel plates under eccentric compression

Ying Qin,Gan-Ping Shu,Er-Feng Du,Rui-Hua Lu 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.29 No.3

In this research, the explicit closed-form local buckling solution of steel plates in contact with concrete, with both loaded and unloaded edges elastically restrained against rotation and subjected to eccentric compression is presented. The Rayleigh-Rize approach is applied to establish the eigenvalue problem for the local buckling performance. Buckling shape which combines trigonometric and biquadratic functions is introduced according to that used by Qin <i>et al</i>. (2017) on steel plate buckling under uniform compression. Explicit solutions for predicting the local buckling stress of steel plate are obtained in terms of the rotational stiffness. Based on different boundary conditions, simply yet explicit local buckling solutions are discussed in details. The proposed formulas are validated against previous research and finite element results. The influences of the loading stress gradient parameter, the aspect ratio, and the rotational stiffness on the local buckling stress resultants of steel plates with different boundary conditions were evaluated. This work can be considered as an alternative to apply a different buckling shape function to study the buckling problem of steel plate under eccentric compression comparing to the work by Qin <i>et al</i>. (2018), and the results are found to be in consistent with those in Qin <i>et al</i>. (2018).

Effects of graphite additives in electrolytes on the microstructure and corrosion resistance of Alumina PEO coatings

Guo-Hua Lv,Huan Chen,Wei-Chao Gu,Wen-Ran Feng,Li Li,Er-Wu Niu,Xian-Hui Zhang,Si-Ze Yang 한국물리학회 2009 Current Applied Physics Vol.9 No.3

In the present work, graphite grains of different sizes were added into the electrolyte to prepare ceramic coatings on aluminum by plasma electrolytic oxidation (PEO). Scanning electron microscopy (SEM) coupled with an energy dispersive X-ray analysis system (EDX), Raman spectroscopy and X-ray diffractometer (XRD) were used to characterize the coatings. A three-electrode system was used to evaluate the corrosion performances of the coatings in a 3.5 wt.% NaCl solution. It was found that the morphology and corrosion performance of the coatings were significantly influenced by the size of the graphite grains. Compared with bigger graphite grains, finer ones were involved in the oxidation process and embedded within the ceramic coatings, which made the coatings less porous and more compact. Thus, the corrosion resistance of the coatings with embedded graphite grains was greatly improved. In the present work, graphite grains of different sizes were added into the electrolyte to prepare ceramic coatings on aluminum by plasma electrolytic oxidation (PEO). Scanning electron microscopy (SEM) coupled with an energy dispersive X-ray analysis system (EDX), Raman spectroscopy and X-ray diffractometer (XRD) were used to characterize the coatings. A three-electrode system was used to evaluate the corrosion performances of the coatings in a 3.5 wt.% NaCl solution. It was found that the morphology and corrosion performance of the coatings were significantly influenced by the size of the graphite grains. Compared with bigger graphite grains, finer ones were involved in the oxidation process and embedded within the ceramic coatings, which made the coatings less porous and more compact. Thus, the corrosion resistance of the coatings with embedded graphite grains was greatly improved.

Fatigue crack propagation behavior at a notch for needled C/SiC composite under tension-tension loading

Geng Hou,De-Guang Shang,Lin-Xuan Zuo,Lin-Feng Qu,Ming Xia,Yi-Er Guo,Xiang Yin,Shao-Dong Wu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.1

Fatigue test of a needled C/SiC composite with a notch under tension-tension cyclic loading was completed, and the main fatigue crack propagation curve of the needled composite was obtained by the in situ observation of the fatigue process. By analyzing the influence of the failure number and distribution on the tensile loading subjected by 0° fiber bundles, the relationship between the main fatigue crack propagation and the distribution of 0° fiber bundles in the needled composite was established. By observing the fracture microstructure (especially the distribution of 0° fiber bundles) of the needled composite through scanning electron microscopy, the reasons for the varying fatigue resistance of different notched specimens were also explained. In addition, acoustic emission (AE) was also used to analyze the AE energy characteristics during the fatigue crack propagation process of the needled composite.

Post-fire Study on Mechanical Properties of Damaged Ultra-high Strength Concrete

Xiao Lyu,Guang-Hao Jia,Gan-Ping Shu,Xin Zhang,Er-Feng Du,Wen-Ming Wang 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.6

In order to study the eff ect of steel tube, pre-load and temperature on residual performance of heated ultra-high strength concrete (UHSC), an experimental program was carried out to investigate the physical and mechanical properties of UHSC post-fi re in room temperature. With total of 54 standard cylindrical concrete specimens subjected to various temperatures ranging from 62 °C to 496 °C, their residual compressive strength, elastic modulus, peak strain was measured after natural cooling down. By comparing the test results of standard cylindrical concrete specimens with the results of the bare specimens in and after fi re, it is known that the residual compressive strength of standard cylindrical concrete specimens decayed more serious after exposing to same temperature. Seen from the results, the temperature which the specimens suff ered was found to be responsibility to the reduction of the compressive strength, elastic modulus, peak strain. As the temperature up to 300 °C, the strength reduction coeffi cient of UHSC was 0.67 ~ 0.68 and the elastic modulus reduction coeffi cient of UHSC was 0.41 ~ 0.51 with peak strain coeffi cient ε cr ( T ) /ε 0 1.57 ~ 1.67. Finally, based on the analysis of test results, simple formulae were proposed to describe the eff ect of temperature on residual performance of heated UHSC which infi lled the steel tube.