p‐Type InP Nanopillar Photocathodes for Efficient Solar‐Driven Hydrogen Production

Lee, Min Hyung,Takei, Kuniharu,Zhang, Junjun,Kapadia, Rehan,Zheng, Maxwell,Chen, Yu‐,Ze,Nah, Junghyo,Matthews, Tyler S.,Chueh, Yu‐,Lun,Ager, Joel W.,Javey, Ali WILEY‐VCH Verlag 2012 Angewandte Chemie Vol.124 No.43

<P><B>Perfekte Textur</B>: Der Einfluss der Oberflächen‐Nanotexturierung, der TiO<SUB>2</SUB>‐Passivierung und des Ru‐Cokatalysators auf die photoelektrochemische Wasserstoffentwicklung durch p‐InP‐Photokathoden wurde untersucht. Höhere Stromdichten und günstigere Onset‐Potentiale werden nach Oberflächen‐Nanotexturierung beobachtet. NHE=Normalwasserstoffelektrode.</P>

miR-340 Reverses Cisplatin Resistance of Hepatocellular Carcinoma Cell Lines by Targeting Nrf2-dependent Antioxidant Pathway

Shi, Liang,Chen, Zhan-Guo,Wu, Li-li,Zheng, Jian-Jian,Yang, Jian-Rong,Chen, Xiao-Fei,Chen, Zeng-Qiang,Liu, Cun-Li,Chi, Sheng-Ying,Zheng, Jia-Ying,Huang, Hai-Xia,Lin, Xiang-Yang,Zheng, Fang Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.23

Many chemotherapeutic agents have been successfully used to treat hepatocellular carcinoma (HCC); however, the development of chemoresistance in liver cancer cells usually results in a relapse and worsening of prognosis. It has been demonstrated that DNA methylation and histone modification play crucial roles in chemotherapy resistance. Currently, extensive research has shown that there is another potential mechanism of gene expression control, which is mediated through the function of short noncoding RNAs, especially for microRNAs (miRNAs), but little is known about their roles in cancer cell drug resistance. In present study, by taking advantage of miRNA effects on the resistance of human hepatocellular carcinoma cells line to cisplatin, it has been demonstrated that miR-340 were significantly downregulated whereas Nrf2 was upregulated in HepG2/CDDP (cisplatin) cells, compared with parental HepG2 cells. Bioinformatics analysis and luciferase assays of Nrf2-3'-untranslated region-based reporter constructor indicated that Nrf2 was the direct target gene of miR-340, miR-340 mimics suppressing Nrf2-dependent antioxidant pathway and enhancing the sensitivity of HepG2/CDDP cells to cisplatin. Interestingly, transfection with miR-340 mimics combined with miR-340 inhibitors reactivated the Nrf2 related pathway and restored the resistance of HepG2/CDDP cells to CDDP. Collectively, the results first suggested that lower expression of miR-340 is involved in the development of CDDP resistance in hepatocellular carcinoma cell line, at least partly due to regulating Nrf2-dependent antioxidant pathway.

Empirical mode decomposition based on Fourier transform and band-pass filter

Zheng-Shou Chen,Shin Hyung Rhee,Gui-Lin Liu 대한조선학회 2019 International Journal of Naval Architecture and Oc Vol.11 No.2

A novel empirical mode decomposition strategy based on Fourier transform and band-pass filter techniques, contributing to efficient instantaneous vibration analyses, is developed in this study. Two key improvements are proposed. The first is associated with the adoption of a band-pass filter technique for intrinsic mode function sifting. The primary characteristic of decomposed components is that their bandwidths do not overlap in the frequency domain. The second improvement concerns an attempt to design narrowband constraints as the essential requirements for intrinsic mode function to make it physically meaningful. Because all decomposed components are generated with respect to their intrinsic narrow bandwidth and strict sifting from high to low frequencies successively, they are orthogonal to each other and are thus suitable for an instantaneous frequency analysis. The direct Hilbert spectrum is employed to illustrate the instantaneous time-frequency-energy distribution. Commendable agreement between the illustrations of the proposed direct Hilbert spectrum and the traditional Fourier spectrum was observed. This method provides robust identifications of vibration modes embedded in vibration processes, deemed to be an efficient means to obtain valuable instantaneous information.

A novel design method for improving collapse resistances of multi-story steel frames with unequal spans using steel braces

Zheng Tan,Wei-hui Zhong,Bao Meng,Shi-chao Duan,Hong-chen Wang3,Xing-You Yao,Yu-hui Zheng 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.47 No.2

The bearing capacities resisted by the two-bay beams of multi-story planar frames with unequal spans under column removal scenarios differ considerably owing to the asymmetric stress on the left and right beams connected to the failed column and cause the potential for beams with larger span-to-depth ratios to be unable to exert effectively, which is disadvantageous for resisting the vertical load in unequal-span frame structures. To address this problem, the structural measure of adding braces to the weak bays of multi-story unequal-span frames was proposed, with the objective of achieving a coordinated stress state in two-bay beams with unequal spans, thereby improving the collapse resistance of unequal-span frame structures. Before conducting the numerical simulation, the modeling methods were verified by previous experimental results of two multi-story planar frames with and without steel braces. Thereafter, the effects of the tensile and compressive braces on the collapse behavior of the frame structures were elucidated. Then, based on the mechanical action laws of the braces throughout the collapse process, a detailed design method for improving the collapse resistance of unequal-span frame structures was proposed. Finally, the proposed design method was verified by using sufficient example models, and the results demonstrated that the design method has good application prospects and high practical value.

Instantaneous multi-mode identification and analysis of vortex-induced vibration via a mode decomposition method

Chen, Zheng-Shou,Rhee, Shin Hyung Elsevier 2019 Applied ocean research Vol.93 No.-

<P><B>Abstract</B></P> <P>The dynamic characteristics of marine risers/pipes often present serried modes with various frequencies due to high levels of structural flexibility and slenderness, especially when the flow velocity is non-uniformly distributed along the span. Therefore, the vortex-induced vibration (hence VIV) for slender risers/pipes is usually characterized by multi-mode motions. In this paper, by means of a newly developed empirical mode decomposition (EMD) method which contributes to more efficient instantaneous multi-mode identification and analysis, new characteristics of a multi-mode “lock-in” vibration process of a large-scale flexible pipe subject to shear flow were discussed. Because the two-degree vibration along the span can be analyzed simultaneously, the effects of multi-mode VIV were investigated systematically. From the given illustrative examples, it was found that the vibration energy diffusion between the fluid and the structure, and among the participating modes, may be repeatable and reversible, or even irreversible, which causes VIV to be highly intricate. The coexistence of multiple modes, energy transfer, and mode switching/jump is observed when the reduced velocity is relatively high. The multi-dominant mode phenomenon is also found in both cross-flow (CF) and in-line (IL) VIVs. Energy transfers between the CF and IL directions occasionally occur, and CF VIV is apt to dominate the vibration process, because it is superior to IL VIV with the increment of the reduced velocity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> By means of a newly developed empirical mode decomposition (EMD) method, new characteristics of a multi-mode “lock-in” vibration process of a large-scale flexible pipe subject to shear flow were discussed. </LI> <LI> The vibration energy diffusion between the fluid and the structure, and among the participating modes, may be repeatable and reversible, or even irreversible, which causes VIV to be highly intricate. </LI> <LI> The multi-dominant mode phenomenon is found in both cross-flow (CF) and in-line (IL) VIVs. </LI> <LI> In contrast to IL VIV, CF VIV is superior and prone to dominate the vibration process with the increment of the reduced velocity. </LI> <LI> Energy transfers between the CF and IL directions occasionally occur. </LI> </UL> </P>

Grem1 accelerates nucleus pulposus cell apoptosis and intervertebral disc degeneration by inhibiting TGF-β-mediated Smad2/3 phosphorylation

Chen Shunlun,Lei Linchuan,Li Zemin,Chen Fan,Huang Yuming,Jiang Guowei,Guo Xingyu,Zhao Zhuoyang,Liu Hui,Wang Hua,Liu Caijun,Zheng Zhaomin,Wang Jianru 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Intervertebral disc degeneration (IVDD) is a main cause of low back pain, and inflammatory factors play key roles in its pathogenesis. Gremlin-1 (Grem1) was reported to induce an inflammatory response in other fields. This study aimed to investigate the mechanisms of Grem1 in the degenerative process of intervertebral discs. Dysregulated genes were determined by analyzing microarray profiles. The expression of Grem1 in 17 human disc samples (male:female = 9:8) and rat models (n = 5 each group) was measured by western blotting (WB), real-time quantitative PCR (RT-qPCR), and immunohistochemistry (IHC). The regulatory effects of Grem1 on apoptosis were examined using siRNAs, flow cytometry, immunofluorescence (IF), and WB. The therapeutic effect was evaluated by locally injecting specific Grem1 siRNA into IVDD rats. The expression of Grem1 was significantly increased in human degenerative intervertebral discs; furthermore, the expression of Grem1 positively correlated with the level of intervertebral disc degeneration. Grem1 was significantly overexpressed in tumor necrosis factor (TNF)-α-induced degenerative NP cells. Apoptosis in degenerative NP cells transfected with siRNA targeting Grem1 was significantly lower than that in the control group. Specific Grem1 siRNA markedly repressed the development of IVDD in surgery-induced IVDD rats. These results indicated that the expression of Grem1 was positively correlated with the severity of intervertebral disc degeneration, and Grem1 siRNA could inhibit Grem1-induced apoptosis and extracellular matrix alterations by mediating the TGF-β/Smad signaling pathway. This study may provide a therapeutic strategy for alleviating inflammation-induced apoptosis associated with intervertebral disc degeneration.

Study on the transient flow induced by the windbreak transition regions in a railway subject to crosswinds

Zheng-Wei Chen,Syeda Anam Hashmi,Tanghong Liu,Wenhui Li,Zhuang Sun,Dongrun Liu,Hassan Hemida,Hong-Kang Liu 한국풍공학회 2022 Wind and Structures, An International Journal (WAS Vol.35 No.5

Due to the complex terrain around high-speed railways, the windbreaks were established along different landforms, resulting in irregular windbreak transition regions between different subgrade infrastructures (flat ground, cutting, embankment, etc). In this paper, the effect of a windbreak transition on the wind flow around railways subjected to crosswinds was studied. Wind tunnel testing was conducted to study the wind speed change around a windbreak transition on flat ground with a uniform wind speed inflow, and the collected data were used to validate a numerical simulation based on a detached eddy simulation method. The validated numerical method was then used to investigate the effect of the windbreak transition from the flat ground to cutting (the “cutting” is a railway subgrade type formed by digging down from the original ground) for three different wind incidence angles of 90º, 75º, and 105º. The deterioration mechanism of the flow fields and the reasons behind the occurrence of the peak wind velocities were explained in detail. The results showed that for the windbreak transition on flat ground, the impact was small. For the transition from the flat ground to the cutting, the influence was relatively large. The significant increase in the wind speeds was due to the right-angle structure of the windbreak transition, which resulted in sudden changes of the wind velocity as well as the direction. In addition, the height mismatch in the transition region worsened the protective effect of a typical windbreak.

Fast Response Research of Magnetically Controlled Reactor

Chen Feng,Wang Jun,Zheng Hao,Lu Wenhua,Tian Cuihua,Yuan Jian,Chen Baichao,Yuan jiaxin 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.10

As a kind of reactive power compensation equipment with control flexibility and high reliability, magnetically controlled reactor (MCR) is widely used in reactive power compensation, over-voltage limitation and other aspects. However, low responding speed has severely limited the application of MCR. Especially when applied to suppress voltage flicker and arc suppression coil, the slow response of MCR will decrease the stability of control system, even causing the system shock. To improve the response performance of MCR, in this paper, the working principle of MCR has been analyzed, and a fast response structure of MCR has been designed with the novel fast response structure, fast excitation and rapid demagnetization can be achieved. According to the simulation and experiment results, the effectiveness of the proposed structure is verified by limiting the response time in 30ms.

Effect of bidirectional internal flow on fluid.structure interaction dynamics of conveying marine riser model subject to shear current

Chen, Zheng-Shou,Kim, Wu-Joan The Society of Naval Architects of Korea 2012 International Journal of Naval Architecture and Oc Vol.4 No.1

This article presents a numerical investigation concerning the effect of two kinds of axially progressing internal flows (namely, upward and downward) on fluid.structure interaction (FSI) dynamics about a marine riser model which is subject to external shear current. The CAE technology behind the current research is a proposed FSI solution, which combines structural analysis software with CFD technology together. Efficiency validation for the CFD software was carried out first. It has been proved that the result from numerical simulations agrees well with the observation from relating model test cases in which the fluidity of internal flow is ignorable. After verifying the numerical code accuracy, simulations are conducted to study the vibration response that attributes to the internal progressive flow. It is found that the existence of internal flow does play an important role in determining the vibration mode (/dominant frequency) and the magnitude of instantaneous vibration amplitude. Since asymmetric curvature along the riser span emerges in the case of external shear current, the centrifugal and Coriolis accelerations owing to up- and downward internal progressive flows play different roles in determining the fluid.structure interaction response. The discrepancy between them becomes distinct, when the velocity ratio of internal flow against external shear current is relatively high.

Preceding Vehicle Identification for Cooperative Adaptive Cruise Control Platoon Forming

Chen, Zheng,Park, Byungkyu Brian IEEE 2020 IEEE transactions on intelligent transportation sy Vol.21 No.1

<P>Cooperative adaptive cruise control (CACC) has shown great potential in enhancing traffic efficiency and sustainability. While past research efforts focused on the development of CACC systems and their demonstrations, very few of them considered in detail how to form a CACC platoon in real traffic, where the proper identification of preceding vehicle is required. To ensure safe and reliable CACC operations, the following vehicle needs to establish the correct connection with its preceding vehicle. Although this can be done by matching information shared by surrounding vehicles with the ego-vehicle’s radar measurements, the existence of sensor/global positioning system (GPS) errors makes it a challenging task. Considering possible sensor/GPS errors in real traffic, this paper proposes a procedure of identifying preceding vehicle under fully connected vehicle environment and evaluates three preceding vehicle identification systems (PVIS), namely, location-based PVIS, distance-based PVIS, and integrated PVIS combining both location and distance information. The mathematical models of PVISs are developed. The performance evaluation of the PVISs is conducted based on real vehicle trajectory data from the Next Generation Simulation (NGSIM) program, which reflects how vehicles’ relative positions change in a high-density segment of highway. The feasibility, performance, and potential of the three PVISs are compared. The results show that location-based PVIS requires a relative positioning accuracy below 1.1 m to ensure an acceptable identification time with zero failure rate. The integrated PVIS has the best performance, providing 99% confidence in identifying preceding vehicle within 1.3 s under typical sensor error settings.</P>