双向两车道交通流模型的车辆转道规则研究

在对已有双向两车道模型的车辆转道规则研究的基础上,考虑驾驶员转道特性,提出均一车辆双向交通流模型两种新的车辆转道规则,并绘制了新车辆转道规则的交通流基本图.模拟结果表明,当逆行道初始密度较小时,与单车道模型相比,两种新规则均能够提高母车道的车辆通行能力,且通过选择合适的模型参数,模拟误差率<5‰,与实测数据近似.

痫性放电实现异体间转道并致痫动物的研究报道

目的观察青霉素癫痫模型痫性放电能否被引导电极转道至异体大鼠脑内并致痫。方法实验大鼠海马局部注射青霉素建立癫痫模型,通过引导电极拟将痫性放电导入异体大鼠同侧海马,观察实验大鼠的行为学、脑电图变化。结果致痫组、痫能导出组12只大鼠全部点燃,痫能导入组6只大鼠亦出现痫性发作,痫能导出组痫性发作时程缩短,致痫组、痫能导出组、痫能导入组大鼠脑电图均可记录到痫性波;对照组、电极组无痫性发作。结论实验性痫性放电可通过引导电极在异体大鼠脑组织间传导,脑内痫性放电有可能被电极导出。

自体脑外转道模式下青霉素致痫大鼠海马C-fos、C-jun表达的影响

观察在脑内置入引导电极接自体脑外肌肉组织对青霉素致痫大鼠行为学、脑电图(EEG)及海马C-fos、C-jun的表达,探讨其对大鼠痫性发作的影响。实验动物随机分为三组,每只6只,分别为致痫组(海马内微注射青霉素制备痫性发作模型)、脑电转道组(致痫灶置入引导电极并接自体脑外肌肉组织)及对照组(脑内置入引导电极,不致痫)。观察各组大鼠行为学、EEG变化并应用免疫组化方法检测海马C-fos、C-jun的表达。实验中观察到致痫组、脑电转道组大鼠痫性发作次数无显著差别;脑电转道组EEG放电次数较致痫组显著减少(P<0.05);4 h点脑电转道组注药侧海马CA3、CA1区C-fos、C-jun表达明显低于致痫组注药侧(P<0.05)。本实验证实了自体脑外转道模式下,引导电极置入减少了致痫大鼠痫性放电次数,下调了致痫大鼠海马C-fos、C-jun的表达。

转道和尚创建新加坡普陀寺、普觉禅寺相关问题研究

本文详细考察了转道法师在新加坡创建佛教寺庙的经过。转道法师在新加坡兴建普陀寺和普觉禅寺时,正是汉传佛教在新加坡逐渐扎根之时,理清这两所寺庙复杂的创建过程,有助于我们更好地认识中、新两国佛教间的渊源,也对当今中国佛教走向世界有着重要启示。

车辆长度和速度对双车道交通流的影响

为研究大型车辆转道及敏感驾驶行为对公路交通的影响,在SDNS(Sensitive Driving Nash)交通流模型基础上,引入长短车辆转道规则,假定双车道上同时存在长度和最大速度均不同的车辆,建立混合交通流模型.在周期性边界条件下,模拟得到当转道概率、混合比例、减速概率、车辆长度、速度等参数改变时,混合交通流的速度、流量与密度的基本图.仿真结果表明,系统临界密度、最大平均速度、流量随减速概率增加而减小;当慢速长车占总车辆比例大于50%时,更容易产生阻塞,此时车辆转道成功率小于5%;当系统中长车比例为50%时,流量峰值仅为0.42,比全小车的情况减少了20%;长车是造成转道困难的主要因素,当转道概率均为50%时,系统长车比例从25%增加至75%,转道成功率最大值由6.32%减少至2.78%.

相邻两航天器相对运动近似方程的解析解及比动能方程

给出了地心引力场中受控航天器相对目标航天器运动的推力加速度随时间线性变化时Ｈｉｌｌ方程的解析解，根据Ｈｉｌｌ方程导出了受控航天器相对目标航天器运动的比动能方程，并讨论了比动能方程在上述两航天器轨道相遇和轨道交会问题中的应用．

Akt和mTOR蛋白在肾透明细胞癌中的表达及意义

目的探讨Akt和mTOR蛋白是否可作为一种新的诊断肾透明细胞癌标志和药物靶向治疗的靶点。方法采用免疫组化和逆转录聚合酶链反应(RT-PCR)技术对60例肾透明细胞癌组织和30例癌旁正常肾组织中的Akt和mTOR的蛋白及mRNA表达进行检测分析。结果 Akt和mTOR蛋白及mRNA在肾透明细胞癌组织中均呈高表达,在癌旁正常组织中均呈低表达(P<0.05);mTOR和Akt蛋白在肾细胞癌组织中的阳性表达率呈正相关。结论 Akt、mTOR蛋白在肾透明细胞癌中的高表达与肾细胞癌的发生有关,可作为一种新的肾细胞癌诊断标志物。

课程思政视域下《轨道交通联锁系统》课程教学改革与实践

本文从分析轨道交通联锁系统课程教学改革现状出发,提出了基于课程思政的轨道交通联锁系统课程教学改革新路径,并从教学内容、教学方法、教学模式、考核评价等方面系统阐述了课程思政改革的思路和方法,从而有效实现思政育人与专业课程相辅相成、有机融合,促进轨道交通联锁系统课程的理论知识、实践技能和思政素质三位一体、全面提升。

试论城市轨道交通对土地空间的利用

城市轨道交通是包含现代有轨电车、城市地铁、城市轨道、市郊快速列车等在内的整个城市交通体系的重要组成部分.

乒乓缓存在地震采集系统中的应用

由于数据处理系统的吞吐量和响应时间的限制,地震数据采集无法进行连续响炮,两炮之间必须要有一定的时间间隔,即死时间。为了消除死时间,设计并实现了一种地震数据的乒乓缓存机制,在乒乓缓存的同时进行了地震数据的时序道序转换。详细介绍了乒乓缓存控制器的硬件和FPGA设计方法。硬件上实现乒乓缓存机制和时序道序转换能够消除地震采集系统的死时间,降低上位机软件的开发难度,提高采集仪器的稳定性和实时性。

国际市场“平行进口”问题分析

平行进口(Parallel Import),指国际贸易中非正规渠道的进口,国际营销中非正规渠道的销售。平行进口的发生,与国际市场营销的定价策略密切相关。只要同一商品在各国存在价格差,只要存在自由流动的人员,平行进口就极易发生。各国经济管理当局对平行进口态度不一,但总的趋势可能走向在一定规范下的许可。这种情况将促使拥有全球化品牌的跨国公司逐渐考虑实行全球价格统一的策略。

星载GPS定轨中精密GPS卫星钟差的改正和应用

低轨道卫星星载GPS精密定轨的最主要的误差源是在SA影响下GPS卫星钟的高频抖动。为了克服这一误差，本文分析了在SA影响下GPS卫星钟差变化的特性，探讨了利用GPS地面跟踪站的观测数据估算GPS卫星钟的可行性，建立了相应的算法和软件系统，并把由地面跟踪站的实测数据估算的GPS卫星钟差应用于星载GPS定轨计算，得到1m的定轨精度。

Effect of equal-channel angular pressing and aging on corrosion behavior of ZK60 Mg alloy

Commercial ZK60 Mg alloy was processed by multi-pass equal-channel angular pressing（ECAP） and subsequent aging to investigate the effect of grain refinement and second-phase redistribution on its corrosion behavior. Electrochemical tests show that the fine-grained samples after more ECAP passes have higher corrosion current densities（Jcorr） in the polarization curves, lower charge-transfer resistance（Rt） values in the EIS plots. The severe plastic deformation decreases the alloy corrosion resistance besides the well-known strengthening and toughening. Scanning Kelvin probe（SKP） measurement shows that the anodic and cathode sites are homogeneously distributed on the surface of the fine-grained alloy, which inhibits localized corrosion. The SKP potential, having linear relationship with the corrosion potential（φcorr）, decreases with increasing the ECAP pass. Furthermore, the post-ECAP aging can slightly improve the corrosion resistance of the fine-grained ZK60 Mg alloy and enhance the comprehensive performances, due to the stress relief and uniform distribution of second-phase particles.

Large-scale manufacturing of aluminum alloy plate extruded from subsize billet by new porthole-equal channel angular processing technique

To manufacture plate by the combination of equal channel angular processing （ECAP） and porthole die extrusion techniques, a novel technique, namely portholes-equal channel angular processing （P-ECAP）, was studied. Extrusion of AL6005A plate used for the bullet train plate was investigated by finite element method. The relevant porthole dies involving ECAP technique in channels were designed. Dimensional changes in the scrap part of the extrudate obtained after extrusion from the P-ECAP die, with different channel angles, were predicted. Effects of the channel angle and extrusion speed on the maximum temperature of the workpiece and other field variables were evaluated. At the channel angle of 160° of P-ECAP dies, the extrudate exhibited the optimal performance and the least amount of extrudate scrap was obtained. The optimal extrusion speed was 3-5 mm/s. Moreover, with the increase in ram speed from 1 to 9 mm/s, the peak extrusion load increased by about 49% and the maximum temperature was increased by about 70 ℃. The effective strain exhibited ascending trend in the comer of the ECAP deformation zone. In the solder seam and the side of die bearing of extrudate, the maximum principal stresses were tensile stress.

Equal channel angular extrusion of NiTi shape memory alloy tube

As a new attempt, equal channel angular extrusion （ECAE） of nickel-titanium shape memory alloy （NiTi SMA） tube was investigated by means of process experiment, finite element method （FEM） and microscopy. NiTi SMA tube with the steel core in it was inserted into the steel can during ECAE of NiTi SMA tube. Based on rigid-viscoplastic FEM, multiple coupled boundary conditions and multiple constitutive models were used for finite element simulation of ECAE of NiTi SMA tube, where the effective stress field, the effective strain field and the velocity field were obtained. Finite element simulation results are in good accordance with the experimental ones. Finite element simulation results reveal that the velocity field shows the minimum value in the corner of NiTi SMA tube, where severe shear deformation occurs. Microstructural observation results reveal that severe plastic deformation leads to a certain grain orientation as well as occurrence of substructures in the grain interior and dynamic recovery occurs during ECAE of NiTi SMA tube. ECAE of NiTi SMA tube provides a new approach to manufacturing ultrafine-grained NiTi SMA tube.

Aging behavior and mechanical properties of 6013 aluminum alloy processed by severe plastic deformation

Structural features, aging behavior, precipitation kinetics and mechanical properties of a 6013 Al–Mg–Si aluminum alloy subjected to equal channel angular pressing （ECAP） at different temperatures were comparatively investigated with that in conventional static aging by quantitative X-ray diffraction （XRD） measurements, differential scanning calorimetry （DSC） and tensile tests. Average grain sizes measured by XRD are in the range of 66-112 nm while the average dislocation density is in the range of 1.20×10^14-1.70×10^14 m^-2 in the deformed alloy. The DSC analysis reveals that the precipitation kinetics in the deformed alloy is much faster as compared with the peak-aged sample due to the smaller grains and higher dislocation density developed after ECAP. Both the yield strength （YS） and ultimate tensile strength （UTS） are dramatically increased in all the ECAP samples as compared with the undeformed counterparts. The maximum strength appears in the samples ECAP treated at room temperature and the maximum YS is about 1.6 times that of the statically peak-aged sample. The very high strength in the ECAP alloy is suggested to be related to the grain size strengthening and dislocation strengthening, as well as the precipitation strengthening contributing from the dynamic precipitation during ECAP.

Effect of processing route on grain refinement in pure copper processed by equal channel angular extrusion

An experimental study of the microstructures in pure copper billets processed by 8 passes of equal channel angular extrusion （ECAE） via an extended range of processing routes with a 90° die is carried out. Each processing route is defined according to the inter-pass billet rotation angle （χ）, which varies from 0° to 180°. According to the generation of high-angle boundaries and reduction of grain size by electron backscatter diffraction （EBSD） measurements, the grain refinement is found to be most efficient for route with χ=90°and least efficient with χ=180°, among the seven routes studied. This trend is supported by supplementary transmission electron microscopy （TEM） measurements. Comparison of the EBSD and TEM data reveals the importance of considering the non-equiaxity of grain structures in quantitative assessment of microstructural differences in ECAE-processed materials.

Strain rate-dependent high temperature compressive deformation characteristics of ultrafine-grained pure aluminum produced by ECAP

To explore the effect of strain rate ε on the high temperature deformation characteristics of ultrafine-grained materials, the deformation and damage features as well as microstructures of ECAP-treated pure Al at different temperatures T and strain ratesε were systematically studied through compression tests and microscopic observations. The increase in ε eliminates strain softening at T≤473 K, and largely enhances the yield strength and flow stress at 473?573 K. The shear deformation dominates the plastic deformation of ECAP-treated Al. Many cracks along shear bands (SBs) are formed at T≥473 K and secondary SBs basically disappear at 1×10?3 s?1; however, at 1×10?2 s?1, cracks are only observed at temperature below 473 K, and secondary SBs become clearer at T≥473 K. The microstructures of ECAP-treated Al mainly consist of sub-grains (SGs). The increase in ε inhibits the SG growth, thus leading to the increases both in yield strength and flow stress at high temperatures.

Influence of dye molecular structure on electron transfer in 2,9,16,23-tetracarboxy zinc phthalocyanine sensitized solar cell

2, 9, 16, 23-tetracarboxy zinc phthalocyanine （ZnTCPc） is synthesized and characterized by physicochemical and theoretical methods and it is used as a photosensitizer in dye-sensitized solar cells （DSSC）. The excited lifetime, band gap and frontier orbital distribution of ZnTCPc are investigated by fluorescence spectra, cyclic voltammetry and quantum calculation. The results show that the excited lifetime and band gap are 0. 1 ns and 1.81 eV, respectively. Moreover, it is found that the highest occupied molecular orbital （HOMO） location is not shared by both the zinc metal and the isoindoline ligands, and the lowest unoccupied molecular orbital（LUMO） location does not strengthen the interaction coupling between ZnTCPc and TiO：. As a result, the ZnTCPc-DSSC gains a short-circuit current density of 0. 147 mA/cm2, an open-circuit photovoltage of 277 mV, a fill factor of 0. 51 and an overall conversion efficiency of 0. 021%.