究竟哪种光对光合作用最有效?——对2009年高考理综山东卷第26题第3小题的讨论

<正>1题目图5表示温室内光照强度(E)与作物光合速率(v)的关系。在温度、水分和无机盐均适宜的条件下,当E相似文献   

基于决策支持的控制环境作物生产管理系统

控制环境作物生产的相关管理决策问题主要包括资金预算分配决策、环境控制决策、以及作物生产经济最优决策等.针对解决这些管理问题的需要,设计了基于决策支持的控制环境作物生产管理系统,系统以MS Access数据库的方式表示模型,并在试验温室中运行此系统,验证了相关模型.     

智能温室多点温度检测系统电路设计与仿真

温度检测系统是智能温室中的重要系统之一,因为温度决定着卷帘系统、风机系统、补光系统等自动控制系统模块的工作,而且精确的温度采集系统还决定着植物的生长。为了精确采集温室的温度,本文设计了一款基于嵌入式微控制器单片机作为上位机和美国DALLAS公司的可编程分辨率的1-Wire数字温度传感器DS18B20构成的多点温室温度检测采集系统,通过在EDA软件——Proteus平台中进行电路设计与仿真,实现了多点温度采集与显示。在实际应用中,该多点温度检测电路的特点是温度采集精度高、电路成本低、功耗小、系统稳定性高,可以推广应用。     

塑料大棚,温室补充CO2气肥的原理及操作技术

调节和控制作物光合作用是农业生产的核心。提高光合作用效率就能提高产量。影响光合率的主要因素之一是二氧化碳的浓度。在一定范围内，：二氧化碳浓度越高，植物的光合率就越大；反之，光合率就越低。农作物光合作用所需的二氧化碳浓度范围是50ppm～10000ppm，小于50ppm，则光合作用不能正常进行，作物停止生长；大于10000ppm，则作物呼吸作用明显受到抑制，作物因能量不足，活动减弱，不利于作物生长；高于10snpm，作物会中毒死亡。作物生长所需的上氧化碳最适浓度为10OOPPm，而空气中二氧化碳浓度一般为340PPm（体积比0．033％，重量…     

基于MSP430的智能温室控制系统设计

针对目前智能温室控制系统功能单一,成本高昂,稳定性不足等问题,设计了一款基于MSP430的智能温室控制系统.以低功耗的处理器MSP430为下位机的核心,合理选择传感器件,优化设计接口电路,完成信号采集和处理任务,直接控制执行机构调节参数,降低了对上位机的硬件要求.上位机软件设计了数据分析、报表统计等功能,可满足不同用户的多样化需求.通过系统测试,证明该温室智能控制系统性能稳定,控制参数符合生产要求.     

教学型温室大棚电源系统的研制

研制了一套既能满足农机专业本科生机电一体化的课程实验教学,又能满足部分研究生科研工作需要的教学型温室大棚。该温室大棚不仅能模拟出真实的外界环境变化,还能通过传感器及多套控制系统,采集模拟环境的变化对大棚的内部环境自动进行实时调节,达到农业生产的需求。特别针对单片机控制系统中,不同的传感器、执行机构对电源需求的不同,而专门设计了教学型温室大棚的电源供给系统,能够将原有的220 V AC单相电转变成5、12、24 V的稳定电压,提供给不同的设备使用,并进行供电系统功耗的要求计算。同时根据系统控制的要求给出单片机系统的控制流程图,使其能满足教学型温室大棚的控制系统需求。     

精细农业生产中Web监控系统设计

精细农业(Precision Agriculture)基于信息技术和现代农业经营管理理念,是传统农业走向高科技农业的必然趋势。新疆是农业大省,农业在新疆经济全局中占有举足轻重的地位,发展精细农业是新疆农业发展的必经之路。精细农业中,解决作物生产环境的智能监测、作物生长状况的实时监控等尤为重要。依托新疆农业大学大学生创新项目,以目前温室栽培和蔬菜大棚为原型,利用Web技术,实现了环境数据的实时显示和监测。     

第四代温室材料阳光板

目前我国现代温室建设主要用玻璃、双层薄膜等作为温室建设的覆盖材料.采用这些材料建造的现代温室主要存在的问题是,温室的能耗高,抵御自然灾害的能力差,在遇到冰雹、大雪等自然灾害时,温室自身将受到严重的破坏,温室中种植的作物同时受到很大损失,薄膜用过后还将造成白色污染.     

大棚温室环境监控系统的设计

为了更好地控制大棚温室环境,提高作物产量,设计了大棚温室环境监控系统。系统对温室大棚的温度、湿度、光照和CO2浓度等信号进行了监测,一旦某些参数值超过设定的上、下限值,微控制器将发出报警,并提示对相应参量进行人工或自动调节控制。通过在永州苗圃农场对4号温室实地检测（此温室种植黄瓜）,该装置对农作物产量的提高起到了积极作用。     

依据单片机设计的温度湿度控制系统分析

随着国家新兴农业的不断发展,整个农业活动中的科技含量逐渐增加.而温室作为高科技农业中的重要组成部分,对整个农业生产的推动力逐渐增加.据有关数据表示,我国国产温室如今正以每年180万公顷的面积飞速发展.在温室的发展过程中,整个温室温度和湿度的合理控制能够有效提高温室作物的产量和质量,提高资源的利用效率和质量.伴随科学技术的不断发展,关于温室温度湿度管理方面的研究也逐渐形成了一定的体系.长期以来,我国国产温室中关于温度湿度的控制系统科技含量较低,管理混乱,因此,在引入单片机设计下的温度湿度控制系统能够转化形成智能型控制系统,通过智能系统和程序来管理温室的温度和湿度.本文拟从单片机的作用入手,引入温度湿度控制系统的操作模型,进而阐述其工作原理和改进之处,从而推动这一研究及早进入实用化.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.