The Experimental Investigation of Recirculation of Air-Cooled System for a Large Power Plant

The paper introduces thermal buoyancy effects to experimental investigation of wind tunnel simulation on direct air-cooled condenser for a large power plant. In order to get thermal flow field of air-cooled tower, PIV experiments are carried out and recirculation ratio of each condition is calculated. Results show that the thermal flow field of the cooling tower has great influence on the recirculation under the cooling tower. Ameliorating the thermal flow field of the cooling tower can reduce the recirculation under the cooling tower and improve the efficiency of air-cooled condenser also.

Efficiency of white lupin in the removal of mercury from contaminated soils: Soil and hydroponic experiments

This study examined the ability of the white lupin to remove mercury （Hg） from a hydroponic system （Hg concentrations 0, 1.25, 2.5, 5 and 10 μmol/L） and from soil in pots and lysimeters （total Hg concentration （19.2 ± 1.9） mg/kg availability 0.07%, and （28.9 ± 0.4） mg/kg availability 0.09%, respectively）, and investigated the accumulation and distribution of Hg in different parts of the plant. White lupin roots efficiently took up Hg, but its translocation to the harvestable parts of the plant was low. The Hg concentration in the seeds posed no risk to human health according to the recommendations of the World Health Organization, but the shoots should not be used as fodder for livestock, at least when unmixed with other fodder crops. The accumulation of Hg in the hydroponically-grown plants was linear over the concentration range tested. The amount of Hg retained in the roots, relative to the shoots, was almost constant irrespective of Hg dose （90%）. In the soil experiments, Hg accumulation increased with exposure time and was the greater in the lysimeter than in the pot experiments. Although Hg removal was the greater in the hydroponic system, revealing the potential of the white lupin to extract Hg, bioaccumulation was the greatest in the lysimeter-grown plants; the latter system more likely reflects the true behaviour of white lupin in the field when Hg availability is a factor that limits Hg removal. The present results suggest that the white lupin could be used in long-term soil reclamation strategies that include the goal of profitable land use in Hg-polluted areas.

Wu Zhengyi and his contributions to plant taxonomy and phytogeography

Wu Zhengyi,a master in science and a giant in botany,was born in Jiujiang,Jiangxi province,China 100 years ago and passed away on June 20,2013 in Kunming,China.He was an Academician of the Chinese Academy of Sciences,Professor and Director Emeritus of Kunming Institute of Botany,Chinese Academy of Sciences。

Potential of plant identification apps in urban forestry studies in China:comparison of recognition accuracy and user experience of five apps

Information on species composition of an urban forest is essential for its management.However,to obtain this information becomes increasingly difficult due to limited taxonomic expertise.In this study,we tested the possibility of using plant identification applications running on mobile platforms to fill this vacuum.Five plant identification apps were compared for their potential in identifying urban tree species in China.An online survey was conducted to determine the features of apps that contributed to users’satisfaction.The results show that identification accuracy varied significantly among the apps.The best performer achieved an accuracy of 74.6%at the species level,which is comparable to the accuracy by professionals in field surveys.Among the features of apps,accuracy of identification was the most important factor that contributed to users’satisfaction.However,plant identification apps did not perform well when used on rare species or outside of the regions where they have been developed.Results indicate that plant identification apps have great potential in urban forest studies and management,but users need to be cautious when deciding which one to use.

Experimental Study on Working Performance of Rice Rope Direct Seeding Machine

Structure and sowing principles of rice rope direct seeding machine are introduced. In order to test the machine＇ s working performance, such as compacting effect, sowing depth, influence of sowing device to rice rope, etc., field experiments were conducted. It is concluded that mean slip ratio of compacting wheel 1 is 4.44%, wheel 2 is 5.58%, wheel 3 is 7.81%, and wheel 4 is 6.96%; mean depth of planting is 29.72 mm, and mean variability coefficient of planting depth is 6.39%. Maximum variability coefficient of planting depth is 8.40%. Rice rope＇s snapping is closely related with the machine＇s speed and guide thread wheel by sowing device orthogonal experiments. Test results show that the machine has a rational design, safe work and meets to the requirements of planting. This study has laid the foundation for further studying the project.

Are Invasive Genotypes Superior? An Experimental Approach Using Native and Invasive Genotypes of the Invasive Grass <i>Phalaris Arundinacea</i>

The admixture and recombination of individuals from the native range into a new range may lead to the production of invasive genotypes that have higher fitness and wider climatic tolerances than the native genotypes. In this paper, we compare the survival and growth of native EU and invasive NA genotypes when planted back into the native EU range near where the EU genotypes were collected. We test this hypothesis using the invasive wetland grass Phalaris arundinacea. If invasive genotypes have evolved to have higher survival and growth, then they should outperform the native EU genotypes under field conditions that are better suited to the EU genotypes. Individual plants of the wetland grass, Phalaris arundinacea collected from native Europe (Czech Republic (CZ) and France (FR)) and North America (Vermont (VT) and North Carolina (NC)) were planted into common gardens in Trebon, Czech Republic (49.0042&deg;N, 14.7721&deg;E) and Moussac, France (43.9808&deg;N, 4.2241&deg;E). Invasive genotypes from North Carolina (NC) survived as well or better than native genotypes in both the Trebon and Moussac garden. Additionally, invasive NC genotypes suffered higher herbivore damage than native genotypes but their growth and survival were not significantly different than genotypes from the other re-gions. A companion field experiment that simulated biomass removal through grazing indicated that invasive NC genotypes recovered faster following grazing than genotypes from other regions. Our results suggest that not all invasive genotypes are superior and regional differences in aggressiveness between invasive genotypes are as great as differences between individuals from native and invasive populations. Introduction of genotypes leading to invasion depends upon the environmental conditions and the suitability of the climate for the introduced individuals.

Clonal Transgenerational Effects Transmit for Multiple Generations in a Floating Plant

Environmental conditions of a parent plant can influence the performance of their clonal offspring,and such clonal transgenerational effects may help offspring adapt to different environments.However,it is still unclear how many vegetative generations clonal transgenerational effects can transmit for and whether it depends on the environmental conditions of the offspring.We grew the ancestor ramets of the floating clonal plant Spirodela polyrhiza under a high and a low nutrient level and obtained the so-called 1^(st)-generation offspring ramets of two types(from these two environments).Then we grew the 1^(st)-generation offspring ramets of each type under the high and the low nutrient level and obtained the so-called 2^(nd)-generation offspring ramets of four types.We repeated this procedure for another five times and analyzed clonal transgenerational effects on growth,morphology and biomass allocation of the 1^(st)-to the 6^(th)-generation offspring ramets.We found positive,negative or neutral(no)transgenerational effects of the ancestor nutrient condition on the offspring of S.polyrhiza,depending on the number of vegetative generations,the nutrient condition of the offspring environment and the traits considered.We observed significant clonal transgenerational effects on the 6^(th)-generation offspring;such effects occurred for all three types of traits(growth,morphology and allocation),but varied depending on the nutrient condition of the offspring environment and the traits considered.Our results suggest that clonal transgenerational effects can transmit for multiple vegetative generations and such impacts can vary depending on the environmental conditions of offspring.

勉县玉米-大豆带状复合种植玉米品种筛选试验

玉米-大豆带状复合种植技术目标是保证带状复合种植条件下玉米与单作相比不减产,增收一季豆。与玉米常规种植相比,种植的株行距变化较大,密度增加,玉米品种的株型、耐密性、抗逆性、丰产性等指标成为此项技术应用成功的前提。通过试验,“1.8m带型2+2模式”玉米-大豆带状复合种植玉米品种主推登海605、农科大8号和延科288,搭配种植五单2号、中金368。

2BP-2000型水稻育秧播种机分盘装置研制

针对现有育秧播种机分盘装置生产效率较低、高速作业时易出现卡盘和秧盘输送不连续等问题,该研究设计了一种生产效率不低于2000盘/h的机械气动式自动分盘装置,可快速、准确完成分盘和供盘,适配2BP-2000型水稻育秧播种机高速播种。阐述了分盘装置的基本结构和工作原理,开展分盘、接盘过程分析,确定装置稳定分盘、接盘作业的关键机构与工作参数。分盘稳定性试验结果表明,生产率为1600~2000盘/h时,分盘稳定性不低于98.67%。开展以层叠秧盘数、生产率和秧盘质量为试验因素,以接盘成功率为试验指标的三因素三水平正交旋转组合试验,得到影响接盘成功率的因素主次关系为生产率、层叠秧盘数、秧盘质量,其中生产率、层叠秧盘数对接盘成功率影响显著(P<0.05),秧盘质量对接盘成功率影响不显著(P≥0.05),表明分盘装置对不同质量的秧盘适应性较好,其最优参数组合为:生产率2000盘/h、层叠秧盘数6盘/层、秧盘质量750 g/盘,该条件下分盘装置的接盘成功率均值为98.43%,与预测值仅相差0.29个百分点。研究结果对提高水稻硬盘育秧播种机械化水平具有实用价值。

植物生理学综合设计性实验教学的改进与实践

植物生理学实验是高等院校生物类专业重要的专业基础课程之一,与理论课程相辅相成。在科学技术快速发展阶段,植物生理学实验教学也要与之相匹配,大量的生物学仪器设备在实验中得到广泛应用。针对植物生理学实验中的验证性、演示性实验多,综合设计性实验较少,实验方法新颖性有待提高等问题,对植物生理学实验教学进行了综合改革,设计了适合于当前植物生理学实验发展趋势和教学要求的综合性实验,实现培养学生科学探究、合作精神、自我发展和学习意识及能力的课程目标。

一型手推式玉米小区播种机研制与试验

由于我国育种单位众多且较分散,考虑投入产出比等经济效益指标影响,面临着小区试验面积小、分布不均等问题。针对玉米小区试验播种用工多、出苗差等问题,研制一种简单实用的手推式玉米小区试验播种机。对比国内外研发推广的小区播种机,该机械对操作人员技术要求不高,操作更简单;对播种地块、种子排列没有严格要求,实用性更强。非常切合我国玉米育种现状,具有很好的应用前景。

青菜高密度移栽机植苗机构的设计与试验

目前国内移栽机尚无成熟的适用于青菜等多行密植蔬菜移栽的植苗机构;针对小株距小行距、高效率的密植移栽要求,设计了一种非圆齿轮行星轮系八行同步植苗机构,并进行了运动学仿真和田间移栽试验。对非圆齿轮行星轮系进行了运动学建模与分析,开发了植苗机构辅助分析与优化设计软件;分析了不同机构参数对植苗轨迹姿态的影响,并通过人机交互的方式得到一组满足青菜小株距移栽要求的机构参数;建立了八行同步植苗机构的三维模型,利用虚拟样机仿真技术绘制出仿真轨迹,并与理论轨迹进行对比,以验证植苗机构三维设计的正确性;开展了田间移栽试验,以验证该机构的可行性和实用性。试验结果表明:在作业转速为15r/min、前进速度为55mm/s的情况下,八行植苗机构的作业株距和行距均为110mm,平均植苗成功率为93.9%,移栽密度超过70株/m2,试验移栽效率为240株/min,表明该机构在机械化密植移栽作业中有较高的应用价值。该研究为高密度移栽机植苗机构的研发提供了理论和试验依据,促进了密植型蔬菜钵苗机械化移栽的进程,为密植移栽机的进一步研究提供技术支持和参考。

基于Plant Simulation的白车身侧围焊装线仿真与优化

虚拟仿真技术是目前对焊装生产线进行工艺规划的主要手段。在分析某汽车白车身侧围焊装线的基础上,利用仿真软件Plant Simulation对侧围焊装线建立离散系统仿真模型,对设备工作情况和瓶颈工位进行分析,评估焊装线生产能力;通过设计Experiment Manager分析模块中的多因子试验,将焊装线产量作为指标,暂存区容量及添加位置作为影响因子,对暂存区的配置进行研究。结果表明合适的暂存区容量和添加位置能极大提高焊装线生产能力,为焊装线的优化提供理论依据和科学参考。

以检测为基础的高校转基因试验基地安全管理研究

转基因技术对选育高产、高品质的作物品种和全球粮食安全具有重要贡献。我国高度重视农业转基因技术的研究和发展,但转基因仍然存在一定的环境风险,需要被严格监管。高校转基因试验基地是开展转基因技术及其应用研究的重要平台。该文从转基因植物的种植现状及其潜在风险出发,以浙江大学为例详细介绍了以转基因检测为基础的全方位监管溯源流程,包括从种子—幼苗—果实—秸秆—土壤残留根系等不同阶段的取样检测,提出了以检测为基础的高校转基因试验基地安全监管方式。

防风仿生挖掘铲的设计与试验

针对河北一年生栽种防风采收过程中挖掘装置挖掘阻力大、碎土能力差等问题,设计了一种防风仿生挖掘铲。结合仿生学原理,采用高精度三维扫描技术对鼹鼠前爪最长的第3趾进行仿生数据采集,运用Imageware逆向设计软件对第3趾点云数据进行处理,以获取轮廓曲线点云数据,并经MatLab软件进行数据拟合得到仿生铲结构曲线。根据根茎类中药材挖掘铲设计原则及栽种防风农艺要求,确定仿生铲关键性能参数,并建立三维模型。利用EDEM离散元仿真分析软件从减阻性能、碎土性能两方面对仿生铲和普通铲的挖掘性能进行对比分析,结果表明:同一仿真条件下,仿生铲减阻率为12.50%,碎土率提升2.92%。通过土槽试验验证仿生铲的挖掘性能及离散元仿真模型的准确性,结果表明:仿生铲减阻率为13.42%,实测值与仿真值相对误差为6.86%,仿生铲具有较好的减阻和碎土性能,所构建离散元仿真模型准确程度较高。

云南不同入侵地区的加拿大一枝黄花表型观测分析

旨在明确加拿大一枝黄花在云南省11个不同发生地区的生态适应性。在同质园条件下分别观测其植物性状及差异。试验可以看出,不同入侵地区发生的加拿大一枝黄花,在同质园条件下进一步的生长、繁殖特征差异显著,其中根萌芽性状指数的变异幅度达到了54.23%,茎秆直径、叶宽和叶形指数变异幅度为23.63%~26.31%。在生物量分配比中,花生物量分配占比最高的植株来自文山州丘北县,叶生物量分配占比最高的植株来自昆明西山区,茎秆生物量分配占比最高的植株来自昆明盘龙区,根部生物量分配占比最高的同样来自昆明盘龙区。进一步测定加拿大一枝黄花POD、SOD、CAT、MDA酶活,来自11个不同入侵地区和生境的植株群体表现出显著差异,其中以文山州丘北点和昆明盘龙点的加拿大一枝黄花植株的茎秆、株高和酶活等性状表现较为突出。通过聚类分析发现植物性状中叶表现出一定差异性,但在气候因子的偏相关性分析中发现,原始地的气候因子对加拿大一枝黄花的影响较小。结果表明,加拿大一枝黄花的植物性状基本稳定一致,但不同入侵地区由于环境条件的不同,表型具有一定差异和可塑性。研究结果对明确该加拿大一枝黄花在云南省的生态适应性奠定重要科学基础,同时为预警、监测及防范该入侵植物的扩展提供科学依据。

育种试验马铃薯播种机的设计与试验

目前,我国马铃薯育种试验播种工作缺少专用机具,存在人工播种劳动量大、效率低、播种质量参差不齐等问题,对育种试验的准确性产生了误差。为此,设计了一种育种试验马铃薯播种机,可用于马铃薯育种试验过程中的播种环节。工作时,采用圆盘式排种装置进行排种,可一次性完成开沟、施肥、播种及起垄作业,在此主要对圆盘式排种装置、导种装置以及种薯存放装置进行了研究分析。田间试验表明:育种试验马铃薯播种机可保证种薯的单株播种,无重种、漏种现象,种植深度合格率为92%,株距变异系数平均值为13.2%,各项性能指标均达到国家设计标准,填补了我国马铃薯育种试验播种缺少专用机具的空白。

水生植物对水体流速的影响规律

为探究水生植物对水体流速的影响规律,设计波—流—水生植物试验方案,其试验装置系统包含P-FIS水生植物-水槽集成系统、HCS水动力控制系统和HMS水动力监测系统;试验条件设计涵盖3类水生植物、6套植株密度及8种水动力工况。研究结果表明,在不规则波作用下,柔性挺水植物和柔性沉水植物的消浪和阻流效果优于刚性挺水植物。波条件下,植株矮的柔性沉水植物过流能力较强;流条件下,植株高的挺水类植物过流能力较强。在测点位置z/H=(0.28±0.04)范围,流速波动达到峰值。柔性挺水植物和柔性沉水植物,在水面以下有繁茂的枝叶结构,其种植密度会显著影响水体流速。研究结果可为水域种植适宜、适量的水生植物提供依据,以期保持水体流动性,同时削减对底泥的冲刷作用,改善水质。

弃土坡面不同建植恢复方式的减流减沙效应

[目的]生产建设项目弃土场进行植被恢复后能够有效防治水土流失。探讨弃土场不同植被恢复方式的减流减沙效果,可以为弃土场后续治理与监管提供理论依据。[方法]选取皖西大别山区生产建设项目弃土,通过人工模拟降雨试验获得不同建植方式(撒播、条播、穴播)和植被恢复阶段(生长期、成熟期、枯萎期)的弃土坡面产流产沙特征,并利用累积距平等方法分析其规律和差异。[结果]相对裸坡,植被恢复可有效延缓初始产流时间,撒播种植的效果最为明显。不同建植方式均起到一定的减流减沙效应,坡面累积产流产沙量呈现出:撒播<条播<穴播<裸坡以及生长期<成熟期<枯萎期的规律;坡面产沙与产流过程存在差异性,减流效应弱于减沙效应。[结论]建植方式减流减沙效益表现为撒播优于条播,穴播最差。生长期减流减沙效益优于成熟期,枯萎期最差。撒播方式在生长期内呈现出最佳的减流减沙效益,减流率和减沙率分别达到49.6%,95.5%。