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Search Results: 1 - 10 of 86642 matches for " 邓社军 "
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路外停车场出入口接入主路车流的车头时距特性分析
Analysis of Vehicle Headway Characters on the Main Road at the Sections of Off-Street Parking Access
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, 叶晓飞
Open Journal of Transportation Technologies (OJTT) , 2014, DOI: 10.12677/OJTT.2014.36022
Abstract: 为了能深入分析我国城市路外停车场出入口接入主路车流的车头时距特性,论文以停车场出入口接入路段的影响区域作为研究对象,以城市常见的双向六车道的四幅路断面形式为例,选择南京市商贸大厦路外停车场出入口接入主路区域进行了数据的采集。综合运用数学方法与SPSS软件,分析了主路各车道的车头时距特性,分别建立了各车道的车头时距概率密度函数,主要研究结论有:①各车道的车头时距不服从正态分布,但是服从对数正态分布;②车道1的概率密度函数为\"\" ;车道2的概率密度函数为\"\" ;车道3的概率密度函数为\"\" 。研究结论为进一步分析车辆的变道特性提供了一定的理论基础。
In order to analyze the headway characters of the main road at the sections of off-street parking access deeply in the cities of China, this paper chooses the influence area of the section of off-street parking access in the city as the research object. Also, the carriageway road including six lanes on two-direction was introduced as a typical example. By using the parameters observed from area of the section of off-street parking access in Nanjing Shangmao Building, a probability density function was established that described the characters of the vehicles on the main road by the method of SPSS and mathematics. Some conclusions can be drawn. First, the headway of all the lanes cannot be subjected to the normal distribution except for logarithmic normal distribution. Secondly, the probability density function of the first lane is \"\", while the second is \"\" and the third is \"\". It would be more beneficial for the further study on change-lane characters of the vehicles.
化石稳定碳同位素记录的中国华北第四纪陆地生态系统演变
,,王杨
科学通报 , 2001,
Abstract: 分析了采自中国华北地区11个第四纪地点共70个哺乳动物牙齿釉质样品的碳同位素组成,结果表明中国华北第四纪陆地生态系统中以C3植物占优势,与纬度相当的巴基斯坦以C4植物占绝对统治地位的情况完全不同.这一巨大差异是由于青藏高原的隆升引起的,模拟结果显示高原北侧将发生显著的温度下降,同时期南侧的温度将上升.南侧的升温使C4植物在巴基斯坦取代了C3植物;而北侧,高原上升引起的温度下降抑制了C4植物的分布,所以直到现代,中国华北地区仍然以C3植物占优势.
胶东半岛西北部金矿带成矿构造应力场及成矿微量元素分布特征研究
,方云,周显强,
地球学报 , 1995,
Abstract: 本文重点研究成矿构造应力场控制的成矿期构造活动,以讨论矿带范围内构造应力、应变能的分布规律,分析矿液运移、富集成矿的机制,并探讨构造应力与成矿元素分布之间的关系和构造作用中的地球化学过程。
路外停车右转驶入对主路上游车流影响的动态长度模型
,叶晓飞,陈峻
公路交通科技 , 2014,
Abstract: 以城市路外停车出入口影响区作为研究对象,将拟停放车辆从最右侧车道右转驶离主路进入停车场的过程对于上游运行车辆的影响区长度表述为停放车辆减速进入停车场距离和跟驰运行车辆的交通波传播距离2个部分。通过理论分析并结合调查数据建立了基于不同驶入时间及不同饱和度下影响区动态长度的计算模型,确定了停车影响时间、速度变化系数等主要参数的适用条件。通过实例并采用VISSIM5.3软件对模型进行了仿真对比验证,主要结论有(1)当驶入时间在4~8s时,饱和度与影响区长度呈现反比关系;驶入时间大于8s时,饱和度与影响区长度呈现正比关系;(2)当饱和度在[0.46~0.5]驶入时间在4~15s时车辆驶入对主路上游车辆没有影响;(3)当饱和度大于0.6,驶入时间大于9s时,车辆驶入对主路上游车辆的影响长度增幅明显。
第四纪初气候转寒事件的化石稳定碳同位素证据
,薛祥煦,
科学通报 , 1998,
Abstract: 研究了甘肃庆阳巴家嘴动物群以马科为主的有蹄类化石,根据牙齿釉质与动物取食草类之间的碳同位素富集关系,恢复了当时该地区草本植物中C3和C4类型所占的比例,表明以C3植物为主.C3草本植物适应于冷湿的气候,分析结果显示巴家嘴动物群生活的时期正处于冰期开始和夏季风退缩的临界状态,是第四纪初全球气候转寒事件的反映
公王岭蓝田人时期的季风气候特征
,魏明建,
第四纪研究 , 1999,
Abstract: 作者用目前在黄上与全球变化研究中使用较多、效果较好的气候代用指标,重建了公王岭蓝田人生活时期高分辨率的气候演变序列。从气候环境变迁的角度,研究了115MaBP的公王岭蓝田人及其伴生动物群与气候环境演化的关系。明确提出,蓝田人及其伴生动物群的死亡与夏季风剧烈衰减和冬季风猛烈增强的气候严重恶化事件有关。这种气候恶化除受与地球轨道变化密切相关的太阳辐射和全球冰量变化的影响外,还与青藏高原的剧烈隆升有关。
路外停车驶入对出入口交通流影响模型
,叶晓飞,陈峻
- , 2016, DOI: 10.11918/j.issn.0367-6234.2016.03.017
Abstract: 为寻找停放车辆的驶入特征与主路车流速度之间的变化规律,以路阻函数(BPR)模型为理论基础,以城市路外停车场出入口接入主路的最右侧车道为研究对象,通过实测数据分析,建立了无停车驶入时出入口影响区范围内该车道的路阻函数模型及停车驶入后对该车道的影响模型.研究结果表明,当无停车驶入时,最右侧车道的车流速度仅与本车道流量密切相关,且该车道的利用系数仅为0.384;当有停车驶入时,最右侧车道的车流速度与停放车辆的驶入频率、驶入影响时间、减速距离及本车道流量等参数密切相关.通过对影响模型的各个参数进一步进行敏感性分析发现:受停车影响后的社会车辆的平均车速与停放车辆的减速距离呈现反比关系,与停放车辆的驶入影响时间呈现正比关系;当减速距离小于10 m时,社会车辆的速度受停车驶入影响变化幅度大.
The BPR model was used to release the law between the characters of parking vehicle and speed of the main road. This paper focuses on the rightmost lane on the main road at the sections of off-street parking access in the city. An impedance function model describing the off-street parking vehicle enters or not was established through the analysis of theory and specific cases based on parameters. Some conclusions can been drawn as follows:firstly, speed of the rightmost vehicle is only related to its flow and proportion of the lane been utilized is only 0.384, while there is no off-street parking vehicle; secondly, speed of the rightmost vehicle is related to the influence time, frequency of parking, deceleration distance and its flow, while the off-street parking vehicle entry into the access. Meanwhile, sensitivity analysis of influence of relative factor on the speed of the social vehicles was conducted. Results show that the parking vehicle's deceleration distance is contrast to the average speed and it's influence time is in proportion to the average speed, while the off-street parking vehicle affected the vehicles on the rightmost lane. Moreover, the social vehicles would be deeply affected by the off-street parking vehicle, while the deceleration distance is less than 10 m.
bepcⅱ逐束团测量系统的研制及应用研究
庆勇,曹建,张源,,何俊
强激光与粒子束 , 2015,
Abstract: ?基于北京正负电子对撞机二期工程储存环,研制了一套逐束团束流测量系统。系统包括模拟前端、数据采集处理控制和显示软件三个部分。储存环束流位置探头的四路信号作为逐束团测量系统的输入,该系统宽带模拟前端完成信号幅度相位的调理,并保证束团间无干扰;四路500mhz模数转换器对信号采样实现逐束团测量;基于现场可编程门阵列的数字信号处理逻辑计算得到每个束团的位置。系统在线实时束流位置测量分辨率优于4.5μm,同时该测量系统可实现实时逐束团振荡幅度和工作点的测量。系统还拥有存储大容量逐束团原始数据的功能,为日常的机器研究提供了有力的测量手段。
bepcⅱ储存环束团流强测量
庆勇,曹建,叶强,,张丛,王鹏飞
强激光与粒子束 , 2014,
Abstract: ?针对北京正负电子对撞机二期工程(bepcⅱ)原束团流强测量系统(bcm)不能稳定运行的问题,对系统进行了升级。利用高速adc对束流位置探头(bpm)信号直接采样,在现场可编程门阵列(fpga)内进行实时数字信号处理,进而得到加速器储存环内的束团流强值。基于反射内存网络,系统可以实现测量结果高速共享、实时显示。升级后系统实现了更高精度的测量,实时显示精度到0.1ma,最佳测量精度达到10μa。通过对系统的触发时钟和算法结构调整,系统实现了长时间的稳定工作,正负电子储存环均实现了对束团流强的均匀性控制,提高了加速器的对撞亮度。
路内停车影响下非机动车流速度模型Symbol`@@
叶晓飞,陈峻,冯树民,
- , 2016, DOI: 10.11918/j.issn.0367-6234.2016.03.019
Abstract: 为解析设置于物理分隔非机动车道的路内停车对非机动车交通运行的影响,将行程时间比拟成生存分析中持续期,构建基于风险持续期模型的非机动车流行程时间和速度模型;提炼和筛选表征路内停车影响的因素,包括非机动车道有效宽度、驶入和驶出事件数、时间障碍率、电动自行车和自行车流量等作为协变量,纳入到模型当中,并利用实测数据标定模型参数.结果表明:模型估计的速度分布特征量化表征了路内停车相关因素的影响效应,模型具有较好拟合优度和预测效果;驶入和驶出事件数、自行车所占比例和时间障碍率对速度具有负效应影响;而非机动车道有效宽度对速度具有正效应影响,随着有效宽度的增加,非机动车流速度降低的风险减小.
To analyze the effect of non-motorized vehicle flow caused by curbside parking on segregated bicycle lane, this study draws an analogy between travel time and duration data of survival analysis. A proportional hazard-based duration model is proposed to establish travel time and speed models of non-motorized vehicle flow. The speed model extracts and screens the influential factors related to curbside parking, including the effective width of bicycle lane, the inbound and outbound parking maneuvers, the time influence rate, electric bike and bicycle flow and so on. The parameters of model are calibrated by using the survey data. The results show the distribution characteristic of speed estimated by the model would give a quantitative analysis of the influence of curbside parking; the model could pass goodness of fit tests and make prediction effectively; the events of inbound and outbound parking maneuvers, the rate of bicycle and the time influence rate show a negative effect on speed whereas the effective width of non-motorized lane shows a positive effect on travel speed; the hazard of non-motorized vehicle speed decreases with the increase of the effective width of bicycle lane.
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