Assessment of the Influence of Tunnel Settlement on Operational Performance of Subway Vehicles

In the realm of subway shield tunnel operations,the impact of tunnel settlement on the operational performance of subway vehicles is a crucial concern.This study introduces an advanced analytical model to investigate rail geometric deformations caused by settlement within a vehicle-track-tunnel coupled system.The model integrates the geometric deformations of the track,attributed to settlement,as track irregularities.A novel“cyclic model”algorithm was employed to enhance computational efficiency without compromising on precision,a claim that was rigorously validated.The model’s capability extends to analyzing the time-history responses of vehicles traversing settlement-affected areas.The research primarily focuses on how settlement wavelength,amplitude,and vehicle speed influence operational performance.Key findings indicate that an increase in settlement wavelength can improve vehicle performance,whereas a rise in amplitude can degrade it.The study also establishes settlement thresholds,based on vehicle operation comfort and safety.These insights are pivotal for maintaining and enhancing the safety and efficiency of subway systems,providing a valuable framework for urban infrastructure management and long-term maintenance strategies in metropolitan transit systems.

Relocation of the 10 March 2011 Yingjiang,China,earthquake sequence and its tectonic implications

An earthquake with Ms5.8 occurred on 10 March 2011 in Yingjiang county, western Yunnan, China. This earthquake caused 25 deaths and over 250 injuries. In order to better understand the seismotectonics in the region, we collected the arrival time data from the Yunnan seismic observational bulletins during 1 January to 25 March 2011, and precisely hand-picked the arrival times from high-quality seismograms that were recorded by the temporary seismic stations deployed by our Institute of Crustal Dynamics, China Earthquake Administration. Using these arrival times, we relocated all the earthquakes including the Yingjiang mainshock and its aftershocks using the double-difference relocation algorithm. Our results show that the relocated earthquakes dominantly occurred along the ENE direction and formed an upside-down bow-shaped structure in depth. It is also observed that after the Yingjiang mainshock, some aftershocks extended toward the SSE over about 10 km. These results may indicate that the Yingjiang mainshock ruptured a conjugate fault system consisting of the ENE trending Da Yingjiang fault and a SSE trending blind fault. Such structural features could contribute to severely seismic hazards during the moderate-size Yingjiang earthquake.

The 20 April 2013 Lushan, Sichuan, mainshock, and its aftershock sequence: tectonic implications

Using the double-difference relocation algo- rithm, we relocated the 20 April 2013 Lushan, Sichuan, earthquake （Ms 7.0）, and its 4,567 aftershocks recorded during the period between 20 April and May 3, 2013. Our results showed that most aftershocks are relocated between 10 and 20 km depths, but some large aftershocks were relocated around 30 krn depth and small events extended upward near the surface. Vertical cross sections illustrate a shovel-shaped fault plane with a variable dip angle from the southwest to northeast along the fault. Furthermore, the dip angle of the fault plane is smaller around the mainshock than that in the surrounding areas along the fault. These results suggest that it may be easy to generate the strong earthquake in the place having a small dip angle of the fault, which is somewhat similar to the genesis of the 2008 Wenchuan earthquake. The Lushan mainshock is underlain by the seismically anomalous layers with low-Vp, low-Vs, and high-Poisson＇s ratio anomalies, possibly suggesting that the fluid-filled fractured rock matrices might signifi- cantly reduce the effective normal stress on the fault plane to bring the brittle failure. The seismic gap between Lushan and Wenchuan aftershocks is suspected to be vulnerable to future seismic risks at greater depths, if any.

Effect of Schisandra chinensis polysaccharide on intracerebral acetylcholinesterase and monoamine neurotransmitters in a D-galactose-induced aging brain mouse model

BACKGROUND： The most prominent characteristic of brain aging is decreased learning and memory ability. The functions of learning and memory are closely related to intracerebral acetylcholinesterase （ACHE） and monoamine neurotransmitter activity. Previous studies have shown that Schisandra chinensis polysaccharide has an anti-aging effect. OBJECTIVE： To explore the effects of Schisandra chinensis polysaccharide on AChE activity and monoamine neurotransmitter content, as well as learning and memory ability in a D-galactose-induced aging mouse brain model compared with the positive control drug Kangnaoling. DESIGN, TIME AND SETTING： Completely randomized, controlled experiment based on neurobiochemistry was performed at the Pharmacological Laboratory, Henan University of Traditional Chinese Medicine from September to December 2003. MATERIALS： Schisandra chinensis was purchased from Henan Provincial Medicinal Company. Schisandra chinensis polysaccharide was obtained by water extraction and alcohol precipitation. Kangnaoling pellets were provided by Liaoning Tianlong Pharmaceutical （batch No. 20030804; state drug permit No. H21023095）. A total of 50 six-week-old Kunming mice were randomly divided into five groups： blank control, model, Kangnaoling, high and low dosage Schisandra chinensis polysaccharide groups, with 10 mice per group. METHODS： Mice in the blank control group were subcutaneously injected with 0.5 mL/20 g normal saline into the nape of the neck each day, while the remaining mice were subcutaneously injected with 5% D-galactose saline solution （0.5 mL/20 g） in the nape for 40 days to induce a brain aging model. On day 11, mice in the high and low dosage Schisandra chinensis polysaccharide groups were intragastrically infused with 20 mg/mL and 10 mg/mL Schisandra chinensis polysaccharide solution （0.2 mL/10 g）, respectively. Mice from the Kangnaoling group were intragastrically infused with 35 mg/mL Kangnaoling suspension （0.2 mL/10 g）, and the mice in the model group were intragastrically infused with the same volume of normal saline （0.2 mL/10 g） once per day for 30 consecutive days. MAIN OUTCOME MEASURES： Two hours after the final administration, pathohistological changes in the cerebral cortex and hippocampus were observed using hematoxylin ＆ eosin staining. AChE activity was detected using chromatometry. Monoamine neurotransmitter content was measured using fluorimetry. Learning and memory was measured using the step down test and darkness avoidance test. RESULTS： Both Schisandra chinensis polysaccharide and Kangnaoling improved pathological injury to the cerebral cortex and hippocampus in a mouse model of brain aging. Compared with the blank control group, AChE activity and content of norepinephrine （NA）, dopamine （DA）, and 5-hydroxytryptamine （5-HT） were significantly decreased in the model group （P 〈 0.01 ）. In contrast, AChE activity and NA, DA, and 5-HT levels significantly increased in the Kangnaoling and high dosage Schisandra chinensis polysaccharide groups （P 〈 0.01）, while NA levels significantly increased in the low dosage Schisandra chinensis polysaccharide group （P 〈 0.01）. Drug treatment improved learning and memory abilities （P 〈 0.01 or P 〈 0.05）. CONCLUSION： Schisandra chinensis polysaccharide significantly increased levels of central neurotransmitters and improved learning and memory in a mouse model of brain aging. The effects of Schisandra chinensis polysaccharide were equal to that of Kangnaoling pellets.

Fog Computing Architecture-Based Data Acquisition for WSN Applications

Efficient and effective data acquisition is of theoretical and practical importance in WSN applications because data measured and collected by WSN is often unreliable, such as those often accompanied by noise and error, missing values or inconsistent data. Motivated by fog computing, which focuses on how to effectively offload computation-intensive tasks from resource-constrained devices, this paper proposes a simple but yet effective data acquisition approach with the ability of filtering abnormal data and meeting the real-time requirement. Our method uses a cooperation mechanism by leveraging on both an architectural and algorithmic approach. Firstly, the sensor node with the limited computing resource only accomplishes detecting and marking the suspicious data using a light weight algorithm. Secondly, the cluster head evaluates suspicious data by referring to the data from the other sensor nodes in the same cluster and discard the abnormal data directly. Thirdly, the sink node fills up the discarded data with an approximate value using nearest neighbor data supplement method. Through the architecture, each node only consumes a few computational resources and distributes the heavily computing load to several nodes. Simulation results show that our data acquisition method is effective considering the real-time outlier filtering and the computing overhead.

龙门山断裂带深部结构与2008年汶川地震发震机理

汶川地震后,为认识发震机理,在龙门山断裂带及周边地区开展了丰富的地震学和地球物理学等方面的野外观测与研究工作,获得了有意义研究成果.近震成像获得的地壳结构显示,以汶川主震震中为界,龙门山断裂带南北两侧波速存在明显差别,以南地区为明显低波速异常,而以北地区为显著横向不均匀性,这也许可以解释汶川地震的余震为何向东北方向延伸.汶川主震发生在高低波速异常的边界,且其下方存在低波速高泊松比异常.这一结果表明,印度-欧亚板块的碰撞挤压在龙门山断裂带附近形成的高温高压导致了部分熔融或流体作用,降低了断层面处的有效正应力,因而诱发了汶川地震.远震成像获得的上地幔结构显示,龙门山断裂带处于松潘-甘孜地块下方的低波速异常向四川盆地下方的高波速异常的过渡区,且这种结构延伸至200~300 km深度,而在地幔转换带中的高波速异常与缅甸弧下方的上地幔高波速异常相连接,说明汶川地震的发生与印度板块深俯冲而形成的"大地幔楔"结构中的低波速异常所代表的热湿物质上涌等动力学过程密切相关.因此,本文认为汶川地震不仅与地壳结构密切相关,而且还受上地幔异常结构的影响.另外,汶川地震还可能与下地壳流、地壳缩短和紫坪铺水库触发等动力学过程有关.

Shield Excavation Analysis: Ground Settlement & Mechanical Responses in Complex Strata

This study delves into the effects of shield tunneling in complex coastal strata, focusing on how this constructionmethod impacts surface settlement, the mechanical properties of adjacent rock, and the deformation of tunnelsegments. It investigates the impact of shield construction on surface settlement, mechanical characteristics ofnearby rock, and segment deformation in complex coastal strata susceptible to construction disturbances. Utilizingthe Fuzhou Binhai express line as a case study, we developed a comprehensive numerical model using theABAQUS finite element software. The model incorporates factors such as face force, grouting pressure, jack force,and cutterhead torque. Its accuracy is validated against field monitoring data from engineering projects. Simulationswere conducted to analyze ground settlement and mechanical changes in adjacent rock and segments acrossfive soil layers. The results indicate that disturbances are most significant near the excavation zone of the shieldmachine, with a prominent settlement trough forming and stabilizing around 2.0–3.0 D from the excavation. Theexcavation face compresses the soil, inducing lateral expansion. As grouting pressure decreases, the segmentexperiences upward buoyancy. In mixed strata, softer layers witness increased cutting, intensifying disturbancesbut reducing segment floatation. These findings offer valuable insights for predicting settlements, ensuring segmentand rock safety, and optimizing tunneling parameters.

In situ stress state and seismic hazard in the Dayi seismic gap of the Longmenshan thrust belt

In the Longmenshan thrust belt,the Dayi seismic gap,an area with few earthquakes,is located between the ruptures of the 2008 Wenchuan Earthquake and the 2013 Lushan Earthquake,with a length of approximately 40–60 km.To date,however,the extent of the seismic hazard of the Dayi seismic gap and whether this gap is under high stress are still hotly debated.To further evaluate the seismic hazard of the Dayi seismic gap with regard to stress,two boreholes(1,000 and 500 m deep)were arranged to carry out hydraulic fracturing in situ stress measurement on either side of the Shuangshi-Dachuan fault zone.This zone has a high seismic hazard and the capacity to undergo surface rupture.Through the analogy of this new data with stability analysis using Byerlee’s Law and existing stress measurement data collected before strong earthquakes,the results show that the area surrounding the Shuangshi-Dachuan fault zone in the Dayi seismic gap(Dachuan Town)is in a state of high in situ stress,and has the conditions necessary for friction slip,with the potential hazard of moderate to strong earthquakes.Our results are the first to reveal the in situ stress profile at a depth of 1,000 m in the Dayi seismic gap,and provide new data for comprehensive evaluation of the seismic hazard in this seismic gap,which is of great significance to explore the mechanism of earthquake occurrence and to help mitigate future disaster.

Novel Porphyrin-Containing Polymer Based Memristor for Synaptic Plasticity Simulation

The porphyrin-based copolymer PZnTPP-SFX is designed and synthesized by alternating porphyrin and spiro[fluorene-9,9'-xanthene]via Suzuki copolymerization.A simple memristor structure of ITO/ZnTPP-SFX/AlOx/Al was fabricated by spin-coating process.The conventional synaptic plasticity is emulated using the single memristor including nonlinear transmission characteristics,spike-timing dependent plasticity and spike-rate dependent plasticity.New spike-voltage dependent plasticity is also found in the memristor which can selectively perform potentiation and depression behaviors at a unipolar voltage.Compared with the device performance of uncoordinated metalloporphyrin polymer,it was found that oxygen vacancies diffuse and migrate into PZnTPP-SFX layer with the assist of coordination metal.This study suggests that porphyrin-based polymers have great promise for synaptic simulation of artificial neural network.

电子烟对小鼠角膜上皮和结膜杯状细胞的影响

目的:研究电子烟对小鼠角膜上皮组织结构及结膜杯状细胞的影响。方法:实验研究。18只雄性c57BL小鼠,8周龄,随机分为A、B、C组,每组6只。A组不做任何干预,B组采用0 mg尼古丁电子烟进行干预,C组采用12 mg尼古丁电子烟进行干预。每日2次,每次30 min。干预12周后,行苏木精-伊红染色观察角膜上皮情况,透射电子显微镜下观察小鼠角膜上皮组织超微结构变化,免疫荧光染色观察Mucin 5AC阳性表达的杯状细胞的改变。各组间结果数据采用单因素方差分析和事后分析。结果:干预12周后,A组上皮细胞层数为5.0±0.7,而B、C组上皮细胞层数分别为7.0±0.7和7.0±0.6,A组与B、C组间差异有统计学意义(F=18.50,P<0.001),而B组和C组间差异无统计学意义。与A组相比,B、C组角膜上皮微绒毛明显减少(F=153.50,P<0.001),长度变短(F=29.54,P<0.001),排列紊乱。在结膜穹隆部的上皮中,B组和C组的Mucin 5AC阳性细胞数目比A组明显减少(F=420.10,P<0.001),但是B组和C组之间Mucin 5AC阳性细胞数目差异无统计学意义。结论:电子烟会损伤小鼠角膜上皮的组织结构,减少结膜杯状细胞的数目。