The spatial-temporal pattern and influencing factors of negative air ions in urban forests, Shanghai, China

Negative air ions are natural components of the air we breathe Forests are the main continuous natural source of negative air ions （NAI）. The spatio-temporal patterns of negative air ions were explored in Shanghai, based on monthly monitoring in 15 parks from March 2009 to February 2010. In each park, sampling sites were selected in forests and open spaces. The annual variation in negative air ion concentrations （NAIC） showed peak values from June to October and minimum values from December to January. NAIC were highest in summer and autumn, intermediate in spring, and lowest in winter. During spring and summer, NAIC in open spaces were significantly higher in rural areas than those in suburban areas. However, there were no significant differences in NAIC at forest sites among seasons. For open spaces, total suspended particles （TSP） were the dominant determining factor of NAIC in sum- mer, and air temperature and air humidity were the dominant determining factors of NAIC in spring, which were tightly correlated with Shanghai＇s ongoing urbanization and its impacts on the environment. R is suggested that urbanization could induce variation in NAIC along the urban-rural gradient, but that may not change the temporal variation pattern. Fur- thermore, the effects of urbanization on NAIC were limited in non-vegetated or less-vegetated sites, such as open spaces, but not in well-vegetated areas, such as urban forests. Therefore, we suggest that urban greening, especially urban forest, has significant resistance to theeffect of urbanization on NAIC.

Precipitation Chemistry and Corresponding Transport Patterns of Influencing Air Masses at Huangshan Mountain in East China

One hundred and ten samples of rainwater were collected for chemical analysis at the summit of Huangshan Mountain, a high-altitude site in East China, from July 2010 to June 2011. The volume-weighted-mean （VWM） pH for the whole sampling period was 5.03. SO2- and Ca2＋ were the most abundant anion and cation, respectively. The ionic concentrations varied monthly with the highest concentrations in winter/spring and the lowest in summer. Evident inter-correlations were found among most ions, indicating the common sources for some species and fully mixing characteristics of the alpine precipitation chemistry. The VWM ratio of [SO]-]/[NO3] was 2.54, suggesting the acidity of rainwater comes from both nitric and sulfuric acids. Compared with contemporary observations at other alpine continental sites in China, the precipitation at Huangshan Mountain was the least polluted, with the lowest ionic concentrations. Trajectories to Huangshan Mountain on rainy days could be classified into six groups. The rainwater with influencing air masses originating in Mongolia was the most polluted with limited effect. The emissions of Jiangxi, Anhui, Zhejiang and Jiangsu provinces had a strong influence on the overall rain chemistry at Huangshan Mountain. The rainwater with influencing air masses from Inner Mongolia was heavily polluted by anthropogenic pollutants.

Numerical Investigation on Flow Pattern of Air-Oil with Different Viscosities Lubrication

In the present work, the performance of oil-air two-phase flow under different lubricant oils was investigated. The simulation method was applied to study the influence of the oil viscosity on the flow pattern, velocity distribution and Re number in oil-air lubrication by FLUENT software with VOF model to acquire the working performance of oil-air lubrication for high-speed ball bearing. This method was used to obtain the optimum lubrication conditions of high-speed ball bearing. The optimum operating conditions that produce the optimum flow pattern were provided. The optimum annular flow was obtained by PAO6 oil with the low viscosity. Reynolds number influences the fluid shape and distribution of oil and air in pipe. The annular flow can be formed when Reynolds number is an appropriate value. The velocity distribution of oil-air two-phase flow at outlet was also discussed by different oil viscosities. The simulating results show that due to the effect of the oil viscosity and flow pattern the velocity decreased and expanded gradually close to the pipe wall, and the velocity increased close to the central pipe. The simulation results provide the proposal for the design and operation of oil-air two-phase flow lubrication experiments in the present work. This work provides a useful method in designing oil-air lubrication with the optimum flow pattern and the optimum operating conditions.

Air Target Fuzzy Pattern Recognition Threat-Judgment Model

Threat-judgment is a complicated fuzzy inference problem. Up to now no relevant unified theory and measur-ing standard have been developed. It is very difficult to establish a threat-judgment model with high reliability in the airdefense system for the naval warships. Air target threat level judgment is an important component in naval warship com-bat command decision-making systems. According to the threat level judgment of air targets during the air defense of sin-gle naval warship, a fuzzy pattern recognition model for judging the threat from air targets is established. Then an algo-rithm for identifying the parameters in the model is presented. The model has an adaptive feature and can dynamicallyupdate its parameters according to the state change of the attacking targets and the environment. The method presentedhere can be used for the air defense system threat judgment in the naval warships.

Optimization and Process Design Tools for Estimation of Weekly Exposure to Air Pollution Integrating Travel Patterns during Pregnancy

A growing number of international studies have highlighted that ambient air pollution exposures are related to different health outcomes. To do so, researchers need to estimate exposure levels to air pollution throughout everyday life. In the literature, the most commonly used estimate is based on home address only or taking into account, in addition, the work address. However, several studies have shown the importance of daily mobility in the estimate of exposure to air pollutants. In this context, we developed an R procedure that estimates individual exposures combining home addresses, several important places, and itineraries of the principal mobility during a week. It supplies researchers a useful tool to calculate individual daily exposition to air pollutants weighting by the time spent at each of the most frequented locations (work, shopping, residential address, etc.) and while commuting. This task requires the efficient calculation of travel time matrices or the examination of multimodal transport routes. This procedure is freely available from the Equit’Area project website: (https://www.equitarea.org). This procedure is structured in three parts: the first part is to create a network, the second allows to estimate main itineraries of the daily mobility and the last one tries to reconstitute the level of air pollution exposure. One main advantage of the tool is that the procedure can be used with different spatial scales and for any air pollutant.

The Analysis of the Line Pattern of Nonlinear Winding Filament on FRP Composite Air Vessel Resisting High Pressure

The FW process is a prefect method of manufacturing FRP composite air vessel resisting high pressure and aerial press vessel.In this paper FW pattern of FRP composite air vessel resisting high pressure was analyzed in a nutshell.The stability of FW patterns on end head is very sensitive to changing of pattern parameter.Consequently,its FW pattern was based on geodesic track.The FW angles and on equators depend on the dimension of end part and the condition of geodesic FW.Generally speaking, the polar holes of rocket engine shell are disproportional.Therefore,the FW angles of the shell column are changeable.The feasi- bility of nongeodesic FW of the shell column was discussed in this paper.Furthermore,it expounded the indispensable condition be- tween the length of shell column and the FW friction coefficient.At the same time,the general mathematic models of the movement control of nongeodesic FW were deduced.

朴素贝叶斯下新型建筑室内空调瞬态能耗预测

新型建筑通常具有较为复杂的结构,使得室内空调系统的能耗受到如建筑朝向、室内人员活动以及设备使用情况等因素影响,导致无法精准预测空调能耗。为此,提出新型建筑室内空调瞬态能耗朴素贝叶斯预测方法。采用K均值聚类(K-means clustering,K-Means)算法将新型建筑室内空调划分为除湿模式、制冷模式、通风模式、制热模式和自动模式,并分析影响空调瞬态能耗的因素,建立朴素贝叶斯预测模型,剔除空调瞬态能耗异常数据,输入至朴素贝叶斯预测模型中,实现新型建筑室内空调的瞬态能耗预测。仿真结果表明,所提方法可有效完成不同模式和运行时间下的瞬态能耗预测,与实际能耗之间的偏离程度较低,期望误差仅为2.31%,变异系数为4.76%,预测误差小。

融合改进NBEATSx和时间注意力机制的空气污染预测

针对现有空气污染预测存在结构复杂、对多元变量与不同时间步间依赖关系提取不充分和多步预测精度低的问题,引入了β分布和非线性动态控制函数改进星鸦优化算法(INOA),优化NBEATSx模型参数,提高收敛精度;并融合时间模式注意力机制(TPA)为不同时间尺度的多外生变量自适应分配权重,再结合预测因子获取时间模式关系.利用所提模型对北京地区的PM2.5进行预测,与传统模型相比精度提高超过18.45%,为空气污染预测提供了一种新方法.

稀密两相状态监测实验平台设计

为了实际测量稀密两相对应的管道尺寸、风压和空气体积流量,设计了一个稀密两相状态监测实验平台。基于空气动力学理论和比例-积分-微分(PID)控制方法,将旁路调节系统应用到实验平台入口处,以控制管道入口空气体积流量,从而实现对物料稀密两相输送的实时监测与调控。该实验平台可实现稀密两相边界条件测试和流形稳定性分析等多项测试。最后,通过多次物料流形实验,验证了旁路调节系统在调控空气体积流量方面的有效性,以及气动测控系统维持物料流形的可行性。

京津冀地区在职人员交通出行模式影响因素调查研究

为了解京津冀地区在职人员交通出行模式影响因素,深入研究交通出行中空气污染暴露水平,通过网络平台对京津冀地区在职人员展开出行模式影响因素问卷调查。利用描述性分析、独立样本t检验和完全随机的单因素方差分析,描述出行模式影响因素的重要程度,并对不同人群间的差异进行比较。结果显示:个人因素、交通因素、气象因素对选择出行模式影响的重要程度得分为2.53±0.99、3.02±1.05、3.21±1.07,气象因素是出行选择的关键影响因素。降雪、拥有交通工具、出行时长、出行距离等因素对京津冀在职人员出行选择有较大影响。不同年龄、学历、家庭年收入群体受个人因素、交通因素和气象因素影响程度存在差异,以上差异有统计学意义(P<0.05)。开展人群交通出行模式判定研究时,应综合考虑上述各方面因素,以提高判定结果的准确性。

中国北方典型地区人群活动模式特色数据集

本文介绍了《典型地区活动模式特色数据集》(Typical Regional Activity Patterns,TRAP),此数据集依托于“大气重污染成因与治理攻关项目”。为了探索大气污染与体力活动的交互效应,我们在空气污染物浓度高于周边地区的典型区域(济南市和保定市)收集了9,221名不同职业和生活方式居民连续3天的活动模式数据。TRAP数据集包括人口学指标(人口学、职业信息、个人习惯和居住条件)和体力活动模式数据(活动地点和活动强度)信息。此数据集提供了体力活动模式的暴露测量数据,数据使用者可以根据自己的特定目的将其与各种终点指标匹配。此数据集可为探究中国北方居民活动模式属性提供证据,为跨学科研究人员制定健康教育及健康促进策略和措施提供证据。

中国东部冬季气温变化的主要区域空间模态及其与大气环流的关系

本文利用1956—2017年我国519个站点逐日气温资料,通过旋转经验正交函数分析方法得到了近62年我国冬季气温变化主要的区域空间模态,研究了其与大气环流的关系,并进一步使用2018—2023年上述站点冬季气温资料进行验证分析。结果表明,我国冬季气温变化有两个较为稳定的区域空间模态:第一模态主要表现为南方大部分地区出现异常低温,低温极值区位于华南和东南沿海区,称之为南方型;第二模态的气温异常信号主要集中在东北地区,称之为东北型。其中,南方型模态与赤道中太平洋的海温呈显著负相关关系,与东亚冬季风的“南北反向”模态呈显著正相关。当冬季赤道中太平洋海温异常偏冷时,东亚南部地区表现为强烈的低层偏北风距平,北方则无显著偏北风距平,造成南方大部分地区出现异常低温。冬季北极涛动与东北型低温模态有显著联系,当北极涛动呈负位相时,冷高压主要集中在极区,高压东侧盛行东北风,造成东北地区冬季气温异常偏低。近6年中,2018年与2021年冬季呈东北型低温模态,其关键环流系统接近北极涛动负位相,验证了该结论。

符号学视角下汉代漆器云气纹在丝巾上的应用探究

汉代漆器云气纹是中华民族的一种传统纹样,是视觉化呈现的表现形式之一。为实现传统文化的传承和创新,将汉代漆器云气纹运用在现代丝巾上,提升丝巾的文化内涵。文章通过莫里斯符号学三个层面:语意层、语构层、语用层,解析汉代漆器云气纹的形态构成和审美意蕴,探究汉代漆器云气纹运用在现代丝巾设计的方法和路径,最后做出设计实践。

水轮发电机定子线棒端部绝缘内部气隙放电特性研究

水轮发电机定子线棒端部绝缘层多为手工绕制而成,其所造成的内部气隙缺陷极易导致局部放电,从而劣化绝缘,降低定子线棒绝缘性能,甚至引发重大电力安全事故。为此,根据实际运行中水轮发电机定子线棒端部的绝缘结构,构建端部主绝缘内部气隙放电模型,结合气隙模型计算放电参数,并基于Simulink研究气隙缺陷放电的发展过程;同时,开展气隙缺陷模型局部放电试验,采用脉冲电流法检测放电特征参数,依据放电统计特征图谱和相关放电理论研究绝缘内部气隙放电规律。结果表明,定子线棒端部绝缘气隙内部电场变化对气隙放电影响较大;气隙空间电荷的累积效应使放电相位发生偏移;气隙放电可分为放电发展阶段、加速发展阶段及稳定发展阶段,根据各阶段的放电特性可以有效判断线棒的绝缘状况;此外,气隙缺陷大小不影响各放电发展阶段的变化趋势。研究结果为水轮发电机定子线棒端部局部放电在线监测和检修维护提供了理论依据,有利于提升发电机的绝缘性能,延长定子线棒使用年限。

医药洁净厂房空调系统节能途径及措施

随着新版药品生产质量管理规范(GMP)对制药洁净室内生产环境要求越来越严格,医药工业净化空调系统的能耗大幅增加。文章从新风独立处理、值班工况、采用高效能冷水机组及凝结水热回收等四方面阐述了医药洁净厂房空调系统节能措施,通过对实际工程的能耗模拟,验证了采取以上措施能做到在满足工艺生产环境的前提下,更好地节约能源、降低生产成本。

川剧脸谱艺术在现代时装中的研究与应用

川剧作为巴蜀地区文化和传统戏剧文化的杰出代表,在2006年被纳为国家非物质文化遗产名录,其中“变脸”更是川剧戏曲中非常具有代表性的一种表演形式。随着快餐时代的来临,冗长繁琐的戏曲服饰渐渐淹没在科技化的浪潮之中。网络时代的到来既是挑战也是机遇,想要继承和发扬川剧脸谱文化,唯有紧跟时代潮流。将川剧脸谱艺术以一种独特的形式融入时装设计之中,让川剧脸谱元素在现代时装美学的基础上进行创新诠释,凸显脸谱文化的鲜明特色。并且深入研究川剧脸谱元素的色彩及图案,探寻脸谱图案与服装材料相结合的表现形式,致力于创造出多元化且符合现代个性审美需求的服装。本人尝试将传统元素作为国风文化推向市场,兼并文化创新,弘扬东方神韵,进行文化输出。

航空承运人强制责任保险国际接轨模式研究——以双循环新格局为背景

双循环新格局对中国航空产业的发展提出了更高的要求,大飞机项目的确立及C919的研发成功标志着中国航空产业取得了质的进步。航空产业作为高新技术领域的一项重要产业,理应是各国未来经济发展的重点,航空保险法治的完善可以为该产业的发展提供保障。分析1999年《蒙特利尔公约》发现,中国航空承运人强制责任保险的范围明显小于国际公约所作出的规定,且存在航空母法有待完善、仅规定地面第三人责任险、责任险立法缺失等不足。国际法因为其形成过程的国际交融性特点,更容易反映为各国所普遍接受的法律原则或规则,因而具有可被吸收和借鉴的特殊意义。鉴于此,中国的相关立法可以在完善相关法律规制、明确责任保险最低限额、保障被保险人权利的模式下进行同国际接轨的探索。

千瓦级风冷燃料电池堆性能的研究分析

风冷燃料电池较传统的质子交换膜燃料电池简化了冷却及供气系统,使其便携性能得到了极大的提高,但是对于风冷电堆的研究大部分趋向于小功率,本文设计、测试、研究了2kW的风冷燃料电池堆的性能,探究了实测风量和理论风量的关系,温度的分布情况以及氢气进出方式对电堆性能的影响。研究结果表明:电堆的实际风量仅为最大风量的80%;电堆的温度分布不均匀,靠近双极板或者电堆中间部分的温度较高;此电堆单电池片数为68片,最大功率达到了1.92kW;单进单出相对于双进双出氢气进出方式,电堆功率相当,但是电压一致性更好。

城市空气污染物与景观园林绿地格局的相关性研究

研究城市空气污染物与景观园林绿地格局的相关性,从而指出相应的景观园林绿地格局优化途径。通过收集11个空气质量监测点的日平均污染物数据,采用双变量相关分析法,从景观、类型、斑块三个尺度水平分析了4个景观格局指数与颗粒物、二氧化硫、氮氧化物的关系。绿地面积占比、形状及连通性与污染物浓度负相关,而绿地斑块形状复杂性则正相关。当绿地面积占比达到7级时,相关性最强。因此,优化途径包括增加绿地面积,优化绿地形状,降低斑块形状复杂性,提高绿地连通性,并适当增加绿地比例,以改善城市空气质量。

基于客流规律的地铁通风空调系统节能运行研究

随着城市地铁系统的快速发展,能耗需求越来越大,合理优化地铁环境,降低能耗标准至关重要。通过对设备运行状况、城市气候环境、客流分布规律、车站通风工艺及行内运营经验等进行数据分析,经过理论论证后选择部分车站开展实践测试。结果证明,车站的温度和二氧化碳指标均符合我国国家标准范围,通过计算每年能耗能够节约200余万元,研究成果满足运营需求,并且比传统的通风空调系统运行方案更加绿色环保,符合低碳型社会的发展趋势。