The Effects of Simulated Acid Rain on Photosynthetic Characteristics of Spring Wheat Leaves at the Jointing Stage

In order to investigate the effect of acid rain on photosynthetic characteristics of spring wheat,spring wheat at the jointing stage was sprayed with simulated acid rain at different pH levels of 1.5,2.5,3.5,4.5 and 5.6,and then,the photosynthetic parameters of spring wheat leaf was monitored.The results indicated that the pH value of simulated acid rain was positively and very significantly correlated with the net photosynthetic rate,stomata conductance,transpiration rate,water use efficiency and the chlorophyll relative content,whereas very significantly and negatively correlated with intercellular CO2 concentration.Due to acid rain,the net photosynthetic rate,stomata conductance,transpiration rate and the chlorophyll relative content decreased by 4.08%-67.04%,17.44%-58.44%,12.08%-48.08% and 12.16%-37.23% respectively,while intercellular CO2 concentration increased by 9.01%-14.29%.After simulated treatment with acid rain,the net photosynthetic rate had high significant positive correlation with stomata conductance,transpiration rate,water use efficiency,and the chlorophyll relative content,but high significant negative correlation with intercellular CO2 concentration.At the same time,transpiration rate was observed to be very significantly and positively correlated to stomata conductance and chlorophyll relative content,being significantly and positively correlated with water use efficiency,and very significantly and negatively correlated with intercellular CO2 concentration.In a word,the influence of simulated acid rain on photosynthetic characteristics of spring wheat leaf became more and more obvious with the increase of hydrogen ion concentration.

Study on the Pollen Rain in Lanzhou University in Spring in 2009

[Objective] The aim was to explore the relationship of pollen types and blooming plants,pollen fertility and meteorological factors during the falling process of pollen in the atmosphere.[Method] The falling record of pollen in Lanzhou University in spring in 2009 was obtained by 10 m platform natural falling method.The pollen falling number,duration,relationship among falling types and surrounding plants,as well as weather were discussed.[Result] Main pollen types included Populus L.,Salix,Paulownia and Platanaceae.Its pollen falling number,duration was consistent with the flowering period of corresponding plants in the garden;the classification and richness of falling of pollen was influenced by wind.The larger the wind was,the richer the variety become.There was basically no pollen from outside.The authors failed to observe the distinct changes of palynological assemblage in sandy storm weather.[Conclusion] The study could lay basis for the study of the modern progress of natural plants pollen.

New Evidences on the Climatic Causes of the Formation of the Spring Persistent Rains over Southeastern China

The spring persistent rains（SPR）over southeastern China（SEC）are a unique synoptic and climatic phenomenon in East Asia.A former study has found that the southwesterly flow which lies on the southeastern flank of the Tibetan Plateau（TP）is one of the deflected westerly flows of the TP,and it is suggested to be the direct climatic cause of SPR.This study found that the southwesterly flow is also highly correlated with the sensible heating of the southeastern TP in interannual variability,in addition to having a high correlation in seasonal variability.These facts suggest that the thermal forcing of the TP is another important climatic cause of SPR.Numerical sensitivity experiments further prove that the mechanical and thermal forcings of the TP are the climatic causes of the formation of the SPR.On the other hand,the Nanling Mountains and Wuyi Mountains（NWM）over southeastern China not only increase the SPR precipitation amount evidently,but also make the SPR rain belt move to the south by blocking the strong southwesterly flow.

Shallow Analysis on the First Spring Soaking Rain Weather and Its Precipitation Enhancement Potential Forecast in Jinzhou Area in 2010

[Objective] The research aimed to study the first spring soaking rain weather and its precipitation enhancement potential forecast in Jinzhou area in 2010. [Method] From the weather situation characteristics, main influence system, forecast service, artificial precipitation enhancement operation and so on, the first spring soaking rain weather process in Jinzhou area in 2010 was summarized comprehensively. [Result] The weather situation characteristics of soaking rain were that the high-altitude cold air was weak, and the low-level warm wet airflow was obvious. The main influence systems were the high-altitude trough, the high-altitude shear line and the ground Mongolian cyclone. The ground inverted trough system advanced northward and got through with the same phase of Mongolian cyclone, which provided the certain energy and water vapor for the precipitation in Jinzhou area. It was one of key reasons for generating the soaking rain. The numerical forecast product played the certain guidance role in the forecast service work. The situation field forecast was accurate, but the precipitation forecast deviation was big. Therefore, the forecast service couldn’t depend on the numerical forecast product simply and totally, and should combine with the actual monitoring data to analyze and apply comprehensively. [Conclusion] The research played the safeguarding role in carrying out the large-scale artificial precipitation enhancement operation successfully in the whole area of Jinzhou.

A Comparative Study of Water Imagery in the Chinese Poem Happy Rain on a Spring Night and American Poem A Drop Fell on the Apple Tree

This essay directs at the water imagery of two poems Happy Rain on a Spring Night and A Drop Fell on the Apple Tree.Although living in different time and place, Chinese poet Du Fu and American poetess Emily Dickinson share some deep understanding of the water. This secret of water imagery is unveiled in this essay with the help of Archetypal Criticism, revealing its significance to the human beings as a race.

Study on the Prediction Method of the First Heavy Rain in the Spring of Xi'an City Based on Markov Chain

[Objective] The aim was to study the Markov chain prediction method of first heavy rain in spring in Xi’an City.[Method] According to the dependent random variables of the occurrence of heavy rain,precipitation in spring in seven meteorological stations in Xi’an City from 1959 to 2010 was selected.Its occurrence date was determined by the standard of first heavy rain in spring in meteorology.According to the length of the sequence of the problem and actual situation,six states were divided.And by dint of Markov chain,first heavy rain prediction model in spring was set up.[Result] The predicted occurrence time of first heavy rain in spring in Xi’an in 2009 and 2010 was consistent with the actual situation.The prediction effect was fine.The method had clear thought and was convenient for calculation,with certain dependence and practicality.[Conclusion] This method provided reference value for the actual forecast of first heavy rain in spring.

Effectiveness of Rain Classroom Intelligent Teaching Design : A Case Study of the Course of Spring Water Tourism Resources

[Objectives]To evaluate the effectiveness of Rain Classroom intelligent teaching in the course of Spring Water Tourism Resources.[Methods]The course of Spring Water Tourism Resources in the course of Overview of Tourism Resources was taken as an example,the pre-class preparation,in-class teaching,and after-class evaluation links were designed separately through the Rain Classroom platform.Then,a questionnaire survey was carried out for the students of Spring Water Tourism Resources.[Results]About 58.3%of the students believed that the greatest advantage of using the Rain Classroom teaching platform is that the learning method is flexible and can improve the ability of independent learning;61.78%of students stated that playing 3D animation in the classroom has the best effect for learning different tourism resources;with the aid of the Rain Classroom platform,the communication between teachers and students becomes more timely,and the students' ability to deal with practical problems can be practiced.[Conclusions]This study is intended to build an intelligent classroom model suitable for tourism management department based on the Rain Classroom platform.It is recommended to promote and apply this model in the teaching of tourism management.

Nourishing as a Fine Spring Rain

BY arrangement of the Office of Chinese Language Council International, my wife Shi Yanhua and I visited the U.S. from November 3 to 19, 2010. Our journey took us from the West Coast to the

清初文人雅集与文学书写——以春雨草堂为中心

清初的文人雅集活动是值得关注的文化现象。经历了改朝换代的鼎革巨变,基于易代本身的残酷、易代史事之于汉人的严重性及其历史记忆的创伤感,置身泛地化、泛政治化的混层型社会文化群落,清初文人在公开场域的雅集唱和呈现出创作思维的趋同性和文学书写的类型化特点。寄情林泉的隐逸诗、以文会友的酬赠诗、诗酒风流的任诞诗、发幽阐微的心志诗都濡染了时代风习,是特殊历史语境下进退失据的汉族文人游寓、聚合、交际、抒怀的典型写影。清初文人雅集的泛地化流动形成了文人群落—群丛—文化圈的网络化延展,具有延续性、开放性和经典化意义。泰州宫伟鏐之春雨草堂成为彼时江南一隅的文渊诗薮、文人重要的“精神桃源”,南北文士躬亲与会,其诗文化活动成为清初江淮流域引人瞩目的文化现象,对认识、审视清初文人雅集与文学书写具有代表性意义。

低温阴雨天气对农作物的影响

对黑龙江省部分地区20年以来4—5月5 cm土壤温度和降水量的研究。分析粮食减产的原因,得出的结论是由于土壤温度低、降水少严重影响农作物生长,导致粮食减产。针对低温阴雨天气带来的危害,应采取的应对措施和面对恶劣天气带来的不利因素进行补救措施进行了探讨。

近60年来广东春季低温阴雨的时空变化特征

利用广东74个国家气象观测站1964—2023年2—4月逐日平均气温资料、日照时数资料,采用线性倾向估计、M-K突变检验、小波分析等方法,对近60年来低温阴雨天气的时空变化特征进行分析。结果表明:广东低温阴雨平均总日数、各等级低温阴雨日数呈西北多南部少的分布特征;北部低温阴雨结束时间迟。广东低温阴雨日数呈减少趋势,年际、年代际波动明显;低温阴雨总日数、重度日数减少及终日提前趋势显著;低温阴雨轻度日数、中度日数下降趋势不显著。区域低温阴雨的总日数、重度日数呈减少趋势;终日呈提前趋势,轻度和中度日数变化趋势不显著。低温阴雨总日数和轻度、重度日数存在准28年的显著周期震荡;中度低温阴雨日数具有准14年的显著周期震荡;终日具有准24年的显著周期震荡。广东低温阴雨总日数、轻度日数及终日在2017年前后发生日数减少和终日提前的突变;低温阴雨重度日数在2002年发生日数减少的突变;低温阴雨中度日数没有突变发生。

基于m法计算桩-土效应时m取值对桥梁动力响应的敏感性分析

本文以某公园人行玻璃悬索桥为研究对象,基于m法选取不同的m值分析桩基础在地震作用下的水平位移和内力响应,研究m值选取对弹性桩水平位移及内力响应的影响程度,为采用m法计算弹性桩水平位移及内力响应时m值的选取提供理论依据,为以后同类型桥梁相关计算提供参考。

自动喷水灭火系统联动控制设计

为保障建筑设计中自动喷水灭火系统联动控制系统的合理性、可靠性,文章从电气专业的角度分析解读自动喷水灭火系统中的五种常见的系统形式。对不同系统的结构形式、设备组成及运行原理进行了比照研究,并对各系统的控制要求、受控部位及信号处理进行了综合的分析,不同自动喷水灭火系统的联动控制有很大的差异,电气设计须对不同的自喷系统做出针对性的联动控制设计。

龙源新解

现在一般认为,龙是人类想象的产物,龙的原型是鱼类、爬行动物结合某些天象而形成的。但该文认为龙的源头在于水,水是动物所必需的,龙与水不能分离。龙乃水之物,是泉瀑之类条形水的升华与神化。龙能幽能显、能短能长的外形活动,与水流的明暗延曲有关,龙字的发音来源悬瀑涌泉的“隆隆”之声。水部中,与龙同一声母且同韵近韵的字大多有水的撞击、奔流之义。以“龙”作为声旁的一些字词,都有收束、聚集、条形性集中的内涵。经笔者长期探索,认为龙最基本、最原始的形象是水,是泉瀑一类特殊的水。水是生命之源,是生存的必需,最贴近人的生活,把泉瀑之类的条形水,想象为龙并不奇怪。

膜式空气弹簧变活塞型线对静刚度特性的影响

现代汽车悬架技术的快速发展,要求汽车在操纵稳定性、行驶平顺性等方面进一步提高性能。高度和刚度可调、吸振能力较佳和使用寿命较长的空气弹簧在中高端乘用车上得到使用。活塞型线对空气弹簧的刚度特性影响较大,不同的活塞型线会直接影响空气弹簧的有效作用直径。文章以乘用车膜式空气弹簧为研究对象,设计了四种不同的活塞型线(L型、S型、O型、反O型),基于有限元分析软件ABAQUS研究分析了不同初始内压下活塞型线对空气弹簧刚度特性的影响。结果表明,O型活塞空气弹簧的承载能力最强,反O型与O型活塞成对称结构,其承载能力最弱,随着初始内压的增大,其承载能力的差距会愈发明显,S型活塞空气弹簧的承载能力介于O型与反O型活塞之间,并表现出理想的反S特性。

水平轴风力机叶片风雨作用下气动性能分析

基于N-S方程和欧拉-拉格朗日法对NREL 5 MW风机叶片在风雨共同作用下的气动性能展开研究。通过数值模拟不同风速对雨滴轨迹的影响,探究风力机叶片表面在不同风速下的雨滴收集情况和在风雨共同作用下风力机叶片表面的压力分布。结果表明:风速对雨滴在流场中的运动轨迹影响十分显著;无论何种风速,风力机收集到的绝大多数雨滴直径范围为1.75~3.75 mm,占有率在85%左右;相较与纯风场,风力机在风雨共同作用下,雨滴的撞击会增强风力机叶片表面的压力。研究结果可为风机的叶片设计和在风电场中的合适布置提供参考。

Particulate matter trends and quantification of the spring sand-dust contribution in Hohhot,Inner Mongolia,from 2013 to 2017

On 10 September 2013,the State Council promulgated the Action Plan for the Prevention and Control of Air Pollution(hereinafter referred to as the Action Plan).To study the variations in the air pollutant concentrations in Hohhot during the implementation of the Action Plan and the effects of various measures,the daily concentrations of air pollutants(fine particulate matter(PM_(2.5)),inhalable PM(PM 10),SO_(2),and NO_(2))in Hohhot published by the China Environmental Monitoring Station were obtained to analyze the general meteorological conditions in Inner Mongolia from 2013 to 2017.The variations and causes of the ambient PM concentration in Hohhot were examined,and the quantitative influence of sandstorms on the ambient PM concentration in Hohhot was analyzed by selecting the spring season with frequent sandstorms as an example.The results showed the following.(1)The air quality in Hohhot continuously improved,and compared with those in 2013,the PM_(2.5)and PM 10 concentrations decreased by 24.6%and 48.2%,respectively,in 2017.However,the air pollutant concentrations remained high,with the average PM_(2.5)and PM 10 concentrations exceeding the national secondary standards by 22.9%and 35.7%,respectively.(2)The reductions in the spring PM_(2.5)and PM 10 concentrations were 5.6%and 8.9%,respectively,and the annual decreases in the PM_(2.5)and PM 10 concentrations were 3.6 and 15.1μg m^(−3)yr−1,respectively,from 2013 to 2017.(3)The absolute contribution ranges of dust weather to the concentrations of PM_(2.5),PM 10,and TSP during 2013–17 were 0.6–5.2μg m^(−3),9.0–16.9μg m^(−3),and 14.7–30.0μg m^(−3),respectively,in Hohhot during the spring.

安徽春季连阴雨与不同类型厄尔尼诺/拉尼娜衰减年的关系

研究安徽省最近几十年春季连阴雨变化规律及其与厄尔尼诺/拉尼娜事件的关系,对提高春季连阴雨认识和防灾减灾具有重要意义。基于1961—2018年安徽省77站逐日降水量和日照时数、美国国家环境预报中心/美国国家大气研究中心(NCEP/NCAR)再分析资料,采用EOF、合成等方法分析了安徽省春季连阴雨的变化特征,并探讨不同类型厄尔尼诺/拉尼娜衰减年对春季连阴雨的可能影响。结果表明:近58 a安徽春季连阴雨日数、频次和最长连阴雨过程天数均呈北少南多的分布特征,其中江南南部是大值中心。连阴雨日数具有明显的减少趋势,平均每10 a减少1.0 d。连阴雨日数变化主要为全省一致型和南北反向型。东部型厄尔尼诺(拉尼娜)衰减年对应安徽春季连阴雨日数偏多(少),中部型厄尔尼诺/拉尼娜衰减年均有利于连阴雨日数偏少。东部型厄尔尼诺(拉尼娜)衰减年对应春季西太平洋副热带高压明显偏强(弱)偏北(南),厄尔尼诺衰减年日本海高压偏强,欧亚中高纬500 hPa高度场为两脊一槽(一槽一脊)形势,乌拉尔山高压脊(低压槽)明显,贝加尔湖为宽广低槽(高压脊),槽底部(脊前)冷空气持续南下,与西北太平洋异常反气旋(气旋)西侧的西南暖湿(东北)气流在江淮上空不断汇合,有利于安徽春季连阴雨日数偏多(少)。中部型厄尔尼诺衰减年西太平洋副热带高压偏强偏西偏南、外兴安岭为低压槽,中部型拉尼娜衰减年贝加尔湖和西太平洋均为异常气旋性环流,江淮地区均受偏北风控制,对应春季连阴雨日数偏少。

商洛金丝峡“6.26”极端短时强降水成因分析

受河套低槽和低涡切变的共同影响,2022年6月26日12∶00-13∶00(北京时,下同)陕西商洛境内商南县西部的金丝峡出现了极端短时强降水(简称“6.26”过程),小时雨强高达108.3 mm·h^(-1),是一次典型的由中尺度新生雷暴引发的局地强降水过程。局地性和突发性强、持续时间短、降水强度大,各家业务模式均出现漏报。本文基于常规气象观测资料及加密自动站观测资料、多普勒天气雷达资料与欧洲中期天气预报中心第五代大气再分析资料(ERA5),对此次短时强降水成因进行了详细分析。结果表明:(1)该过程发生在500 hPa河套低槽配合700 hPa低涡切变缓慢东移的环流背景下,商南地区动力抬升条件和能量条件较好,对流发生前K指数达到42.83℃。(2)局地充沛的水汽加之低层较强的垂直上升运动可将水汽迅速向上输送,有利于在金丝峡形成极端短时大暴雨。(3)金丝峡附近热力非均匀下垫面造成的局地环流和变压风引起的局地流场之间形成的中小尺度地面辐合线是导致金丝峡极端短时强降水的主要原因。金丝峡特殊的河谷地形,一方面有利于触发对流,另一方面阻挡了低层东南气流沿山爬坡抬升,进一步加强了金丝峡上空大气的辐合,促使暴雨增幅。

雨潮共同作用下滨海城镇洪涝模拟研究——以珠海市高新区为例

随着气候变化加剧和城市下垫面的改变,我国滨海城镇地区面临着日益严重的洪涝灾害威胁。文章以珠海市高新区为例,通过构建一、二维耦合水动力模型,模拟不同重现期外海潮位和降雨组合条件下研究区域内淹没情况。结果表明:当外海潮位重现期超过50 a一遇时,将发生海水倒灌,沿海区域受到严重影响;在以暴雨为主工况条件下,城市低洼地区将发生内涝,当遭遇200 a一遇暴雨时,最大淹没水深超过2 m。模拟淹没范围与实际城市易涝点位置吻合良好,结果可为当地防洪避险提供理论依据。