On Millimeter Wave and THz Mobile Radio Channel for Smart Rail Mobility

Guan, Ke,Li, Guangkai,Kurner, Thomas,Molisch, Andreas F.,Peng, Bile,He, Ruisi,Hui, Bing,Kim, Junhyeong,Zhong, Zhangdui IEEE 2017 IEEE Transactions on Vehicular Technology VT Vol.66 No.7

<P>As a widely acknowledged efficient and green transportation model, rail traffic is expected to evolve into a new era of 'smart rail mobility' whereby infrastructure, trains, and travelers will be interconnected to achieve optimized mobility, higher safety, and lower costs. Thus, a seamless high-data rate wireless connectivity with up to dozens of gigahertz bandwidth is required. Such a huge bandwidth requirement motivates the exploration of the underutilized millimeter (mm) wave and terahertz (THz) bands. In this paper, the motivations for developing millimeter wave and THz communications for railway are clarified by first defining the applications and scenarios required for smart rail mobility. Ray-tracing simulations at 100 GHz imply that to form high-gain directional antenna beams, dynamic beamforming strategies and advanced handover design are critical for the feasibility of THz communications to enable smart rail mobility.</P>

Effects of β Air Cooling and Subsequent Cold Rolling on Microstructure and Hardness of Zr702 Sheet

Haotian Guan,Lingguo Zeng,Zhijun Li,Linjiang Chai,Yufan Zhu,Yueyuan Wang,Qin Huang,Ke Chen,Liang‑yu Chen,Ning Guo 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.2

In this work, a Zr702 sheet was subjected to β air cooling and then rolled to 15% reduction at room temperature, with theirdetailed microstructural characteristics characterized by electron channeling contrast imaging and electron backscatterdiffraction techniques. Results show that after the β air cooling, the prior equiaxed grains in the as-received material arecompletely transformed into Widmanstätten structures featured by coarse plates with typical phase transformation misorientationsbetween them. The subsequent 15% rolling allows both slip and twinning (especially the {10–12} type) to beactivated readily, leading to significant grain refinement and the appearance of misorientation angle peaks around 3°–5° and85°. Analyses on kernel average misorientations reveal that there exist very low residual strains in the β-air-cooled specimenwhile they are markedly increased after the 15% rolling and preferably distributed near low-angle and twin boundaries. Hardnessmeasurements show that the specimen hardness is evidently decreased from ~ 199 to ~ 170 HV after the β air cooling,which can be attributed to grain coarsening and the scattered orientations associated with the slow β → α transformation. For the 15%-rolled specimen, however, effective grain refinement by twinning and denser low-angle boundaries jointly leadto ~ 35% hardness increment to ~ 228 HV.

Hybrid prediction method of load-carrying capacity considering boundary condition of expansion joint sleeve and rotation angle of spindle

Yongqiang Guan,Jianmei Wang,Ke Ning,Dingbang Hou 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.10

Taking the double-cone expansion joint sleeve (EJS) as an example, this paper proposes a hybrid prediction method of load-carrying capacity considering the displacement boundary conditions of EJS and rotation angle of spindle, and a comprehensive optimization method for the structure of EJS is established using this method. Firstly, based on the thickwalled cylinder theory and considering the displacement boundary conditions of interference contact surface, a new calculation method for calculating torque is presented, and the main parameters affecting load-carrying capacity are determined. Secondly, the finite element method is used to simulate assembly process and working process of EJS to obtain the ultimate torque, the effects of inner ring, outer ring, taper, elastic modulus, and friction coefficient are investigated. Based on the hybrid prediction results of load-carrying capacity, the multi-objective optimization is carried out using genetic algorithm through the construction of orthogonal experimental combination, the optimization of structural parameters of EJS is realized. The results indicate that the maximum equivalent stress is reduced by 20.88 %, the ultimate torque is increased by 0.23 %, and the mass is reduced by 5.11 %. It is proved that the method can effectively reduce maximum equivalent stress and solve design defects caused by stress concentration.

Expression, Purification, and Characterization of Iron-Sulfur Cluster Assembly Regulator IscR from Acidithiobacillus ferrooxidans

( Jia Zeng ),( Ke Zhang ),( Jian She Liu ),( Guan Zhou Qiu ) 한국미생물 · 생명공학회 2008 Journal of microbiology and biotechnology Vol.18 No.10

Effect of Cisplatin on the Frequency and Immuno-inhibitory Function of Myeloid-derived Suppressor Cells in A375 Melanoma Model

Huang, Xiang,Guan, Dan,Shu, Yong-Qian,Liu, Lian-Ke,Ni, Fang Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.10

Background: To investigate the change of frequency and immuno-inhibitory function of myeloid-derived suppressor cells (MDSCs) after treatment of cisplatin (DDP) in A375 human melanoma model. Materials and Methods: BALB/c nude mice were inoculated with A375 cells to establish the human melanoma model and randomly divided into control group given normal saline (NS) and experimental group treated with DDP (5 mg/kg). The percentages of MDSCs in the tumor tissue and peripheral blood after DDP treatment were detected by flow cytometry. The proliferation and interferon-${\gamma}$ (IFN-${\gamma}$) secretion of T cells co-cultured with MDSCs were analyzed through carboxyfluorescein succinimidyl ester (CFSE) labeling assay and enzyme-linked immunospot (ELISPOT) assay, respectively. Results: In A375 human melanoma model, DDP treatment could significantly decrease the percentage of MDSCs in the tumor tissue, but exerted no effect on the level of MDSCs in peripheral blood. Moreover, DDP treatment could attenuate the immuno-inhibitory function of MDSCs. T cells co-cultured with DDP-treated MDSCs could dramatically elevate the proliferation and production of INF-${\gamma}$. Conclusions: DDP can decrease the frequency and attenuate immuno-inhibitory function of MDSCs in A375 melanoma model, suggesting a potential strategy to augment the efficacy of combined immunotherapy.

Polymer nanofiber network reinforced gold electrode array for neural activity recording

Siting Yang,Ke Xu,Shouliang Guan,Liang Zou,Lei Gao,Jinfen Wang,Huihui Tian,Hui Li,Ying Fang,Hongbian Li 대한의용생체공학회 2023 Biomedical Engineering Letters (BMEL) Vol.13 No.2

Flexible and stretchable neural electrodes are promising tools for high-fidelity interfacing with soft and curvilinear brainsurface. Here, we describe a flexible and stretchable neural electrode array that consists of polyacrylonitrile (PAN) nanofibernetwork reinforced gold (Au) film electrodes. Under stretching, the interweaving PAN nanofibers effectively terminate theformation of propagating cracks in the Au films and thus enable the formation of a dynamically stable electrode-tissue interface. Moreover, the PAN nanofibers increase the surface roughness and active surface areas of the Au electrodes, leading toreduced electrochemical impedance and improved signal-to-noise ratio. As a result, PAN nanofiber network reinforced Auelectrode arrays can allow for reliable in vivo multichannel recording of epileptiform activities in rats.

Stochastic Channel Modeling for Railway Tunnel Scenarios at 25 GHz

Danping He,Bo Ai,Ke Guan,Zhangdui Zhong,Bing Hui,김준형,HeeSangChung,김일규 한국전자통신연구원 2018 ETRI Journal Vol.40 No.1

More people prefer using rail traffic for travel or for commuting owing to its convenience and flexibility. The railway scenario has become an important communication scenario in the fifth generation era. The communication system should be designed to support high-data-rate demands with seamless connectivity at a high mobility. In this paper, the channel characteristics are studied and modeled for the railway tunnel scenario with straight and curved route shapes. On the basis of measurements using the “Mobile Hotspot Network” system, a three-dimensional ray tracer (RT) is calibrated and validated for the target scenarios. More channel characteristics are explored via RT simulations at 25.25 GHz with a 500-MHz bandwidth. The key channel parameters are extracted, provided, and incorporated into a 3rd-Generation-Partnership-Project-like stochastic channel generator. The necessary channel information can be practically realized, which can support the link-level and system-level design of the communication system in similar scenarios.

Failure behaviors of C/C composite tube under lateral compression loading

Yantao Gao,Yuexia Guan,Ke Li,Min Liu,Can Zhang,Jinliang Song 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.7

Mechanical responses and failure behaviors of advanced C/C composite tube are very important for structural component design in nuclear reactor. In this study, an experimental investigation was conducted to study mechanical properties of C/C composite tube. Quasi-static compression loading was applied to a type of advanced composite tube to determine the response of the quasi-static load displacement curve during progressive damage. Acoustic emissions (AE) signals were captured and analyzed to characterize the crack formation and crack development. In addition, the crack propagation of the specimens was monitored by imaging technique and failure mode of the specimen was analyzed. FEM is appled to simulate the stress distribution. Results show that advanced C/C composite tube exhibits considerable energy absorption capability and stability in load-carrying capacity.

The impact of TNFSF14 on prognosis and immune microenvironment in clear cell renal cell carcinoma

Fangshi Xu,Yibing Guan,Peng Zhang,Li Xue,Xiaojie Yang,Ke Gao,Tie Chong 한국유전학회 2020 Genes & Genomics Vol.42 No.9

Background TNFSF14 has been proven to play an important role in various types of tumors. However, its function in renal cell carcinoma (RCC) has not yet been fully elucidated. Objective In order to explore molecular mechanism of RCC, we evaluated the efect of TNFSF14 on RCC progression, prognosis and immune microenvironment. Methods Using TCGA database, the diferential expression of TNFSF14 and its relationships between clinicopathological features and prognosis were determined. Cox univariate and multivariate analyses were successively performed to identify whether TNFSF14 was an independent prognostic factor. The discriminating ability of TNFSF14 in RCC prognosis analysis was validated under the same clinical subgroups. Tumor mutational burden (TMB) of each RCC samples was calculated and the diferential expression of TNFSF14 between high- and low-TMB groups was analyzed. The immune abundances of 22 leukocyte subtypes in each RCC samples were presented through the CIBERSORT algorithm. TIMER database was used to explore the relationships between copy number of TNFSF14 and the infltration levels of 6 immune cells. Results Overexpression of TNFSF14 implied adverse clinicopathological features and poor prognosis. Meanwhile, TNFSF14 was identifed as an independent prognostic factor (HR=1.047, P=0.028) and possessed prevalent applicability in RCC prognostic analysis. TNFSF14 was upregulated in high-TMB group than that in low-TMB group (Log2FC=0.722). Moreover, overexpression of TNFSF14 brought alteration of immune abundance of 8 leukocyte subtypes. Besides, somatic copy number alteration (SCNA) of TNFSF14 was associated with infltration levels of 6 immune cells. Conclusions TNFSF14 has crucial impact on progression, prognosis and immune microenvironment in RCC. Besides, TNFSF14 may be a potential biomarker for predicting the efcacy and response rate of RCC immunotherapy.

Soliton Transmission Experiment Employing Normal Dispersion Fiber with Large Dispersion

Jian Jun Yu,Ke Jian Guan,Bo Jun Yang 한국통신학회 1997 OPTOELECTRONICS & COMMUNICATIONS CONFERENCE Vol.2 No.1