Study on push-out test and bond stress-slip relationship of circular concrete filled steel tube

Yin Xiaowei,Lu Xilin 국제구조공학회 2010 Steel and Composite Structures, An International J Vol.10 No.4

According to the results of 9 circular concrete filled steel tube (CFT) push-out tests, a new theoretical model for average bond stress versus free end slip curve is proposed. The relationship between average bond stress and free end slip is obtained considering some varying influential parameters such as slenderness ratio and diameter-to-thickness ratio. Based on measured steel tube strain and relative slip at different longitudinal positions, the distribution of bond stress and relative slip along the length of steel tube is obtained. An equation for predicting the varying bond-slip relationship along longitudinal length and a position function reflecting the variation are proposed. The presented method can be used in the application of finite element method to analyze the behavior of CFT structures.

Heterogeneously Integrated Thin-film Lithium Niobate Electro-optic Modulator Based on Slot Structure

Xiaowei Li,Yin Xu,Dongmei Huang,Feng Li,Bo Zhang,Yue Dong,Yi Ni 한국광학회 2022 Current Optics and Photonics Vol.6 No.3

Electro-optic modulator (EOM) takes a vital role in connecting the electric and optical fields. Here, we present a heterogeneously integrated EOM based on the lithium niobate-on-insulator (LNOI) platform. The key modulation waveguide structure is a field-enhanced slot waveguide formed by embedding silicon nanowires in a thin-film lithium niobate (LN), which is different from the previously reported LN ridge or etchless LN waveguides. Based on such slot structure, optical mode field area is reduced and enhanced electric field in the slot region can interact well with LN material with high Electro-optic (EO) coefficient. Therefore, the improvements in both aspects have positive effects on enhancing the modulation performance. From results, the corresponding EOM by adding such modulation waveguide structure achieves better performance, where the key half-wave-voltage-length product (V π L) and 3 dBEO bandwidth are 1.78 V · cm and 40 GHz under the electrode gap width of only 6 μm, respectively. Moreover, Lower V π L can also be achieved. With these characteristics, such field-enhanced waveguide structure could further promote the development of LNOI-based EOM.

Study on the Micro-vibration Suppression of a MnCu Spring Isolation Platform with Low Stiffness and High Damping

Xianbo Yin,Yang Xu,Xiaowei Sheng,Song Wan,Yixin Wang 한국항공우주학회 2023 International Journal of Aeronautical and Space Sc Vol.24 No.3

Reaction wheels are the primary micro-vibration sources for microsatellites. To reduce the adverse effects of micro-vibrations, a six-degree-of-freedom (6-DOF) vibration isolation scheme with low stiffness and high damping is proposed. Through six-component force measurements, the harmonic characteristics of the micro-vibrations generated by a reaction wheel are determined. Based on an assumption of small deformation linear elasticity, a dynamic model of a convergent isolation platform is established. With high damping characteristics, helical springs made of MnCu (manganese copper) alloy are selected as the isolation element of the platform. After a modal analysis and stiffness design, the key structural parameters of the isolator are determined. According to the coupling of degrees of freedom, the transmissibility of the isolator is simulated and compared to titanium and aluminum alloys. Combined with on-ground and on-board tests, the effectiveness of the isolation platform is verified. The research shows that the 6-DOF isolation platform based on the MnCu spring realizes multidirectional low-frequency and low-magnitude micro-vibration suppression. The minimum initial isolation frequency of the designed isolator is 16.8 Hz, and the best suppression effect reaches 17.5 dB. The proposed isolator’s application successfully controls high-order harmonics and sensitive load response behaviors.

Experimental study on hysteretic properties of SRC columns with high steel ratio

Xilin Lu,Xiaowei Yin,Huanjun Jiang 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.17 No.3

8 steel reinforced concrete (SRC) columns with the encased steel ratio of 13.12% and 15.04% respectively were tested under the test axial load ratio of 0.33-0.80 and the low-frequency cyclic lateral loading. The cross sectional area of composite columns was 500 mm × 500 mm. The mechanical properties, failure modes and deformabilities were studied. All the specimens produced flexure failure subject to combined axial force, bending moment and shear. Force-displacement hysteretic curves, strain curves of encased steels and rebars were obtained. The interaction behavior of encased steel and concrete were verified. The hysteretic curves of columns were plump in shapes. Hysteresis loops were almost coincident under the same levels of lateral loading, and bearing capacities did not change much, which indicated that the columns had good energy-dissipation performance and seismic capacity. Based on the equilibrium equation, the suggested practical calculation method could accurately predict the flexural strength of SRC columns with cross-shaped section encased steel. The obtained M-N curves of SRC columns can be used as references for further studies.

Vibration Energy Transfer Characteristics of Panels with Multiple Coupling Forms in Satellites

Yan Shen,Yang Xu,Xiaowei Sheng,Song Wan,Xianbo Yin 한국항공우주학회 2023 International Journal of Aeronautical and Space Sc Vol.24 No.5

Micro-vibrations on-board a satellite have degrading effects on the performance of certain payloads like observation cameras. There are numerous sources and extremely complicated transfer paths for micro-vibration in satellites. The vibration energy transfer characteristics of panels with multiple coupling forms in satellites were analyzed, which can guide the vibration isolation measures of satellites. First, the satellite was divided into honeycomb panel subsystems with multiple coupling forms. In the next phase, based on the energy finite element analysis (EFEA), the energy finite element equation of the honeycomb subsystem and the connection matrix at the coupling boundary was established to determine the energy distribution and energy flow characteristics of the multiform coupled honeycomb panels under different excitation frequencies. Finally, the finite difference approximation based on the response obtained from the measurement point array was employed to obtain the energy density. By comparing the results of the experiment and EFEA simulation under different frequency excitations, the average error of the energy density was less than 4 dB, which proved the accuracy of EFEA in the transfer characteristics analysis of the vibration energy of the satellite. The experiment method of vibration transfer based on the finite difference approximation can directly obtain the energy density of the structure.

IL-34 Aggravates Steroid-Induced Osteonecrosis of the Femoral Head via Promoting Osteoclast Differentiation

Wang Feng,Min Hong Sung,Shan Haojie,Yin Fuli,Jiang Chaolai,Zong Yang,Ma Xin,Lin Yiwei,Zhou Zubin,Yu Xiaowei 대한면역학회 2022 Immune Network Vol.22 No.3

IL-34 can promote osteoclast differentiation and activation, which may contribute to steroid-induced osteonecrosis of the femoral head (ONFH). Animal model was constructed in both BALB/c and IL-34 deficient mice to detect the relative expression of inflammation cytokines. Micro-CT was utilized to reveal the internal structure. In vitro differentiated osteoclast was induced by culturing bone marrow-derived macrophages with IL-34 conditioned medium or M-CSF. The relative expression of pro-inflammation cytokines, osteoclast marker genes, and relevant pathways molecules was detected with quantitative real-time RT-PCR, ELISA, and Western blot. Up-regulated IL-34 expression could be detected in the serum of ONFH patients and femoral heads of ONFH mice. IL-34 deficient mice showed the resistance to ONFH induction with the up-regulated trabecular number, trabecular thickness, bone value fraction, and down-regulated trabecular separation. On the other hand, inflammatory cytokines, such as TNF-α, IFN-γ, IL-6, IL-12, IL-2, and IL-17A, showed diminished expression in IL-34 deficient ONFH induced mice. IL-34 alone or works in coordination with M-CSF to promote osteoclastogenesis and activate ERK, STAT3, and non-canonical NF-κB pathways. These data demonstrate that IL-34 can promote the differentiation of osteoclast through ERK, STAT3, and non-canonical NF-κB pathways to aggravate steroid-induced ONFH, and IL-34 can be considered as a treatment target.

3D-QSAR and Molecular Docking Studies on Benzotriazoles as Antiproliferative Agents and Histone Deacetylase Inhibitors

Li, Xiaolin,Fu, Jie,Shi, Wei,Luo, Yin,Zhang, Xiaowei,Zhu, Hailiang,Yu, Hongxia Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.8

Benzotriazole is an important synthetic auxiliary for potential clinical applications. A series of benzotriazoles as potential antiproliferative agents by inhibiting histone deacetylase (HDAC) were recently reported. Three-dimensional quantitative structure-activity relationship (3D-QSAR), including comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA), were performed to elucidate the 3D structural features required for the antiproliferative activity. The results of both ligand-based CoMFA model ($q^2=0.647$, $r^2=0.968$, ${r^2}_{pred}=0.687$) and CoMSIA model ($q^2=0.685$, $r^2=0.928$, ${r^2}_{pred}=0.555$) demonstrated the highly statistical significance and good predictive ability. The results generated from CoMFA and CoMSIA provided important information about the structural characteristics influence inhibitory potency. In addition, docking analysis was applied to clarify the binding modes between the ligands and the receptor HDAC. The information obtained from this study could provide some instructions for the further development of potent antiproliferative agents and HDAC inhibitors.

3D-QSAR and Molecular Docking Studies on Benzotriazoles as Antiproliferative Agents and Histone Deacetylase Inhibitors

Xiaolin Li,Jie Fu,Wei Shi,Yin Luo,Xiaowei Zhang,Hailiang Zhu,Hongxia Yu 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.8

Benzotriazole is an important synthetic auxiliary for potential clinical applications. A series of benzotriazoles as potential antiproliferative agents by inhibiting histone deacetylase (HDAC) were recently reported. Threedimensional quantitative structure-activity relationship (3D-QSAR), including comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA), were performed to elucidate the 3D structural features required for the antiproliferative activity. The results of both ligand-based CoMFA model (q2 = 0.647, r2 = 0.968, r2 pred = 0.687) and CoMSIA model (q2 = 0.685, r2 = 0.928, r2 pred = 0.555) demonstrated the highly statistical significance and good predictive ability. The results generated from CoMFA and CoMSIA provided important information about the structural characteristics influence inhibitory potency. In addition, docking analysis was applied to clarify the binding modes between the ligands and the receptor HDAC. The information obtained from this study could provide some instructions for the further development of potent antiproliferative agents and HDAC inhibitors.

Investigation on Mechanical and AE Characteristics of Yellow Sandstone Undergoing Wetting-Drying Cycles

Yaoyao Meng,Hongwen Jing,Qian Yin,Xiaowei Gu 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.11

The cyclic wetting-drying phenomenon is a complicated physical and chemical process. This kind of process will weaken the properties of rock to some extent. Some fundamental physical parameters of sandstone were first tested to study the weakening influence of wetting-drying cycles on the physical characteristics. Then, the water weakening effect on the mechanical and acoustic emission (AE) characteristics of rock on account of wetting-drying cycles was experimentally studied. Laboratory test results showed that when the number of cycles increased from 0 to 25, the density, P-wave velocity, uniaxial compressive strength (UCS), (elastic modulus (E)) and total AE counts of the rock specimens continuously decreased. However, the water absorption would increase as the number of cycles increased. The functional relationships between the total AE counts and the mechanical parameters (UCS and E) of sandstone after each cyclic number were established based on the test results. In addition, the chemical components and microstructure variations of rock undergoing wetting-drying cycles were examined. From the results, it can be concluded that microcrack growth and expansion inside the rocks undergoing wetting-drying cycles are the main reasons for the attenuation of the rock properties. Moreover, with increasing loading rate, the UCS, E and total AE counts of sandstone after each cyclic number would increase.