深液流悬杯式水培(DFT)设施设计及管理

深液流悬杯式水培技术(DFT)是在营养液膜技术(NFT)的基础上改进的。本文对DFT设施的设计与管理进行了系统的介绍。并对这种无土栽培方式的优缺点进行了科学的评价。     

无土栽培中根腐烂的形成因素及预防措施

无土栽培植物的根,长期浸泡在营养液中,管理不当更易造成烂根,从而导致植株死亡。通过实验证明,水中的溶解氧、营养液成份是否均匀、水中生物以及空气湿度和温度等四个方面都会影响无土栽培植物的根生长,要及早做好预防措施,保护好根的生长,才能使无土栽培成功。     

无土栽培西葫芦营养液性质变化研究

采用营养液栽培模式比较了几种营养液配方在无土栽培西葫芦过程中营养液性质的变化，结果表明：在栽培过程中营养液的性质有较大变化。无土栽培西葫芦各处理营养液的pH值在一日内均表现出明显的上升趋势，由pH6．5上升至pH7．2以上；营养液的溶解氧显著降低，一日内迅速由6mg／L降至4mg／L以下；营养液的EC值在一个营养周期内表现出明显的降低趋势。营养液的EC值与营养液中NO3^--N、P、K的含量呈极显著直线正相关。     

深液流无土栽培（DFT）营养液管理技术

营养液是无土栽培的关键,以黄瓜深液流无土栽培营养液为研究对象,根据实际测得的营养液温度,溶解氧和电导率,观察其试验数据判断对黄瓜生长的影响,并对其进行合理调控和管理,使其在特定时期维持在一定的范围之内,协调好它们之间的相互关系和相互影响,让黄瓜更好地正常快速生长。这一实践性的技术,将有利于无土栽培技术的提高与发展,为今后研究提供依据和方法。     

无土栽培西葫芦营养液性质变化研究

采用营养液栽培模式比较了几种营养液配方在无土栽培西葫芦过程中营养液性质的变化,结果表明:在栽培过程中营养液的性质有较大变化.无土栽培西葫芦各处理营养液的pH值在一日内均表现出明显的上升趋势,由pH6.5上升至pH7.2以上;营养液的溶解氧显著降低,一日内迅速由6mg/L降至4mg/L以下;营养液的EC值在一个营养周期内表现出明显的降低趋势.营养液的EC值与营养液中NO3-N、P、K的含量呈极显著直线正相关.     

营养液膜栽培法介绍

<正>营养液膜技术是水培的一种形式,其作物根系一部分浸在浅层营养液中,另一部分则暴露于种植槽内湿空气之中,由于维持浅层的营养液在根系周围循环流动,很好地解决了水培中空气不足的矛盾。营养液膜技术简称为NFT(Nutrient Film Technique)。用营养液膜技术栽培作物有许多优点,能较好地解决根呼吸对氧的需求;营养液膜技术的种植槽是用轻质的塑料薄膜     

无土栽培的三种方式及幼苗选择

高中生物学教材在“植物的矿质营养”、初中生物学教材在“植物生长需要哪些无机盐”的章节里,都安排了无土栽培的实践活动。所谓无土栽培,就是指不用土壤,而是采用营养液和其他栽培设施,对植物进行的一种特殊培养。由于无土栽培耗时长、难度大、技术要求高,教材上安排的这些实践活动在许多学校就形同虚设。笔者经过几年栽培试验,将无土栽培根据植物营养液和栽培设施的不同划分为三种形式：即普通无土栽培、简易无土栽培和最简无土栽培。三种栽培方式由繁到简、由难到易,分别适合高中、初中、小学不同层次的学生选用。     

改进水稻幼苗无土栽培方法的探讨

无土栽培是指不用土壤而用其它介质培养植物的方法,目前常用的包括水培、雾（气）培、基质栽培。探讨在实验室中不用天然土壤而采用含有植物生长发育必需的基本元素和微量元素的营养液使水稻幼苗正常生长的栽培技术,以期为利用溶液培养法（水培法）培养水稻幼苗提供参考依据。     

芹菜的水培实验

1课题提出 在人们的脑海里,总有这种思维定势;植物是靠土壤生长的,离开土壤就不能生长.而科学家研究表明,植物是靠土壤固定的,它所需要的营养物质是从土壤溶液中吸收的.现在有一种特殊的栽培方法--无土栽培.无土栽培就是不用土壤,一般只用化学肥料或化学试剂配成营养液,来满足植物生长发育所需要的各种无机盐.     

铬（Ⅲ）化学发光传感器的研究

将Ｌｕｍｉｎｏｌ－Ｈ２Ｏ２（ＫＢｒ）－Ｃｒ（Ⅲ）化学发光反应体系中的发光剂Ｌｕｍｉｎｏｌ用离子交换固定法固定在阴离子交换树脂上,串入流动注射系统中,Ｈ２Ｏ２是溶液里的溶解氧在流通池中电解产生的。当一定量的洗脱剂被注入阴离子交换树脂柱时,洗脱下来的Ｌｕｍｉｎｏｌ及试样中的Ｃｒ（Ⅲ）在流通池中与Ｈ２Ｏ２反应,产生化学发光,实现对Ｃｒ（Ⅲ）的在线检测,从而制得Ｃｒ（Ⅲ）化学发光传感器。该传感器的线性范围     

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.