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1.
Initial return and short-term return are two totally different conceptions. When the anticipated year return is evaluated, we should stand on the conception of short-term return not the initial return. Based on the primary conception of the investment return, and considering the cost of purchasing, this paper gives the method of calculating the rate of short-term return. After the experienced analyses, we think there is excess return in the primary market. However, influenced by the low hit rate, only those investors, whose capital over some limit, can get it. The result explains the phenomena that why little investors leave the primary market for the secondary market. From the other way, the result proves that the investors are rational.  相似文献   

2.
冬小麦粒叶比遗传效应分析   总被引:1,自引:0,他引:1  
用9个冬小麦品种按5×4不完全双列杂交设计组配20个杂交组合,对小麦粒叶比的杂种优势和遗传效应进行分析。结果表明,小麦粒叶比表现出一定的杂种优势;一般配合力和特殊配合力方差均达极显著水平,说明亲本的粒叶比差异及杂交互作均对F1代产生遗传差异,该试验中石6021、农大99260080等的一般配合力较大,石6021×农大99260080、鲁麦14×济南17等组合的特殊配合力较大,产生了较强的杂种优势;粒叶比遗传符合加性—显性遗传模型,但以加性效应为主,其遗传决定度达87.65%,狭义遗传力为64.71%;在高粒叶比品种选育上应重视高粒叶比亲本筛选利用和杂交后代的早代选择。  相似文献   

3.
源—库比改变对玉米群体光合和其它性状的影响   总被引:16,自引:0,他引:16  
在抽丝授粉期,通过不去叶、去穗上所有叶、去穗下所有叶和去整株叶的处理,研究了改变源-库比对玉米群体光合速率、产量及其构成因素、以及植株内可溶性糖含量的影响。结果表明,去叶后群体光合速率下降,粒数减少,粒重降低,成粒率下降,植株体内可溶性糖浓度下降。去叶效应的大小顺序是:去整株叶〉去穗上所有叶〉去穗下所有叶。单株籽粒产量减产的最大的是去整株叶,平均减产87%;其次是去穗上所有叶,平均减产51%;去穗  相似文献   

4.
高林森  陈军平 《华北农学报》2006,21(Z2):163-165
盛花前使用SM 盛花期GA3 花后10d GA3处理的藤稔葡萄无核率达到94%以上,单粒重平均增加1.3g,提早成熟一周,但对果实的品质没有影响。  相似文献   

5.
SIMPLE method is used to study the influence of aspect ratio on the natural convection in an enclosure with five discrete heat sources on a vertical wall and an isothermal heat sink on another vertical wall. The range of aspect ratio is from 3. 0 to 12. 22. At high aspect ratio, multiple secondary flow cells can be found,which enhance heat transfer strongly and cause the highest heat transfer coefficient based on cooling area Nuc. With the decrease of aspect ratio,secondary flow cells become weaker gradually and finally reach the lowest Nuc at H/W = 7. 35. If H/W continues to decrease,natural convection is gradually developed,and heat transfer is improved. At H/W = 3. 67,Nuc becomes stable. Then the decrease of aspect ratio will not affect heat transfer. Besides, A heat transfer correlation including the influence of aspect ratio is .also provided.  相似文献   

6.
Summary As a follow up to a previous paper on growth curves (Keuls & Garretsen, 1982) a procedure is described to derive functions of time for growth characters from elementary growth curves which are suited for statistical analysis.For each plot from the parameters , , of the second degree growth curves of type + (t–t) + (t–t)2, corresponding functions of time (of harvest) are obtained for the derived growth characters: relative growth rate (of dry weight per plant), net assimilation rate, leaf area ratio, specific leaf area, leaf weight ratio. The elementary growth curves concern ln W, ln LA and ln LW, where W = dry weight per plant, LA = leaf area per plant, LW = leaf dry weight per plant.Only relative growth rate is a simple linear expression in t, i.e., + 2(t–t), where t represents average harvest time.The functions for the four other growth characters are approximated by quadratic functions in t, such that for each plot a curve is characterized by a triple of parameters f(t), f(t), % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0dh9WrFfpC0xh9vqqj-hEeeu0xXdbba9frFj0-OqFf% ea0dXdd9vqaq-JfrVkFHe9pgea0dXdar-Jb9hs0dXdbPYxe9vr0-vr% 0-vqpWqaaeaabaGaaiaacaqabeaadaqaaqaaaKabGfaammaalaaaba% Gaaiymaaqaaiaackdaaaaaaa!3946!\[\frac{1}{2}\]f(t), representing respectively mean, slope and curvature for that plot at time t The approximation of the function of time is given by f(t) + (t–t)f(t) + % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0dh9WrFfpC0xh9vqqj-hEeeu0xXdbba9frFj0-OqFf% ea0dXdd9vqaq-JfrVkFHe9pgea0dXdar-Jb9hs0dXdbPYxe9vr0-vr% 0-vqpWqaaeaabaGaaiaacaqabeaadaqaaqaaaKabGfaammaalaaaba% Gaaiymaaqaaiaackdaaaaaaa!3946!\[\frac{1}{2}\](t–t)2f(t).These sets of parameters per plot: (, , ) for ln W(t) etc.; (, 2, 0) for RGR(t) or (f(t), f(t), % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0dh9WrFfpC0xh9vqqj-hEeeu0xXdbba9frFj0-OqFf% ea0dXdd9vqaq-JfrVkFHe9pgea0dXdar-Jb9hs0dXdbPYxe9vr0-vr% 0-vqpWqaaeaabaGaaiaacaqabeaadaqaaqaaaKabGfaammaalaaaba% Gaaiymaaqaaiaackdaaaaaaa!3946!\[\frac{1}{2}\]f(t)) for the four other growth characters can be analysed by the MANOVA-procedure for 3 parameters as exemplified by Keuls & Garretsen (1982).  相似文献   

7.
Numerical study is performed to analyse the influence of aspect ratio on the nat-ural convection of high Pr fluid in a cavity with five discrete heaters at the bottom and an isothermalheat snk at the top,The range of aspect ratio is from 0.082 to 0.333, Raw is 107 and Pr is 90.Inthe half of the eavity five independent flow cells seperated by zero stream lines can be observed atsmall aspect ratio,which gradually merge into a single flow when aspect ratio increases and finallybeeome a big cell at A = 0.333.The average nusselt number based on the cooling arca,Nuc,showsthe highest value at A=0.082.With the incrcase of A,Nuc decreases and arrives the lowest valuewhile A=0.138,then increases and reaches an extreme value as A=0.164.After that Nuc fluctu-ates with the variation of increasing rate of flow velocity.  相似文献   

8.
研究施氮时期和光质(红光/远红光,R/FR)对玉米植株形态及产量构成因素的影响,对于探讨高密度种植玉米的生长和产量响应机制具有重要意义。以‘郑单958’和‘鲁单981’2个玉米品种为材料,在盆栽基施和追施2种施氮时期下,采用人工加装远红光LED灯设置低R/FR比值光环境,研究玉米生长生理性状和产量对低R/FR的响应。低R/FR处理后,各取样期植株的高度、总叶面积、比叶重都不同程度增加,而总叶片数却与对照持平;低R/FR处理还降低了叶片的SPAD值,却提高了叶片的净光合速率;低R/FR处理最终提高了玉米果穗的行粒数、穗粒重及果穗总重量,降低了穗轴重,而千粒重变化未达统计显著水平。低R/FR×品种互作和低R/FR×施氮时期在各个农艺性状上互作基本都未达到统计显著水平。低R/FR比值通过增加行粒数提高穗粒重。  相似文献   

9.
康峻菡  胥义 《中国农学通报》2020,36(32):130-139
为了建立扩散型时间-温度指示器(Time-Temperature Indicator,TTI)与鲜银耳品质参数的关联模型,实现TTI对鲜银耳品质的监控,分别研究了4种贮藏温度(5℃、13℃、17℃和23℃)下,扩散型TTI的RGB值及鲜银耳品质参数(失重率、可溶性蛋白质含量、可溶性糖含量以及丙二醛含量)的变化情况,通过反应动力学模型及Arrhenius模型获得了扩散型TTI颜色变化和鲜银耳品质变化的活化能Ea,并建立了扩散型TTI的RGB值与鲜银耳品质参数的关联模型。研究结果表明,在贮藏过程中,随着贮藏时间的延长,TTI的RGB值均呈下降趋势,且贮藏温度越高,RGB值下降幅度越大,其颜色变化的活化能值为36.1135 KJ/mol;随着贮藏时间的延长及贮藏温度的升高,鲜银耳的品质发生了劣变,其品质参数均与扩散型TTI的活化能差值在25 KJ/mol之内;基于扩散型TTI颜色变化与鲜鲜银耳品质参数构建了二者之间的关联模型,经实验验证其相对误差均在15%之内,证明了扩散型TTI在银耳品质监控中的应用潜力。因此,有望将此扩散型TTI用于鲜银耳贮藏过程中的品质监控并实现对银耳品质的预测。  相似文献   

10.
There are some controversies on influences of stone powder on performances of concrete, and its content determination is one of the hot issues of manufactured fine aggregate (MFA) concrete. Slump and compressive strength of limestone MFA concrete were analyzed on contents of stone powder for middle-low strength and different flowability concrete. The experiment results show that there are different optimums percent of stone powder of MFA, such as 5, 10, and 20 for different types of concrete, but the water-powder ratio for them is 0.4. It is concluded that optimum percent of stone powder may be predicted by water-powder 0.4 for middle and low strength MFA concrete.  相似文献   

11.
玉米出籽率、籽粒深度和百粒重的QTL分析   总被引:4,自引:1,他引:3  
为研究玉米出籽率、籽粒深度、百粒重的遗传机制,以豫82×沈137组配的229个F2:3家系为试验材料,采用复合区间作图法进行QTL定位分析。在3个环境下共检测到10个QTL。其中,控制出籽率、籽粒深度、百粒重相关QTL分别为3个、3个和4个,它们的联合贡献率分别为35.5%、28.1%和39.0%。位于第1染色体上介于标记umc1335与umc2236之间控制出籽率的QTL qKR1b和位于第9染色体上介于标记bnlg1209–umc2095之间控制百粒重QTL q100-KW9b,分别解释18.9%和11.7%的表型变异,且作用方式为加性效应,分析表明这些区域可能包含调控玉米籽粒性状关键基因,对剖析玉米产量形成机制具有重要的参考价值。  相似文献   

12.
易秋香  刘英  常存  钟瑞森 《作物学报》2020,46(8):1266-1274
类胡萝卜素(Car)与叶绿素a含量比值(Car/Chla)的变化与植被生长发育变化、环境胁迫及叶片衰老特征等密切相关,可作为植被生理生态及物候的监测指标。不同植被类型和植被品种其色素变化随植被生长发育呈现出不同的变化特征。为了探究适用于干旱区棉花Car/Chla比值估算的光谱指数和估算方法,本研究通过2011年和2012年连续2年的大面积田间试验,获取了棉花不同生育期的叶片及冠层尺度光谱反射率及色素含量信息,对多种光谱指数及偏最小二乘回归(Partial Least Square Regression, PLSR)用于Car/Chla比值和Car估算进行了探讨。对比表明,基于光化学指数(PhotochemicalReflectanceIndex,PRI)的线性和一元二次模型对Car/Chla比值和Car的估算精度最高,由PRI-Car/Chla线性模型得到的叶片和冠层尺度的Car/Chla比值估算值与实测值之间的决定系数R2大于0.6, PRI-Car的R2大于0.36;基于PLSR模型得到的Car/Chla比值估算值与实测值之间的拟合关系略优于基于PRI的估算模型,由其得到的叶片及冠...  相似文献   

13.
analyzing the primary characteristic and the power performance, this article discusses the changing regularities of the ratio in two types of HTC, which have different penetrativity. The effect to the AT efficiency is also discussed. It is pointed out that to find the best match of the percentage of penetrating and engine accommodation coefficient is a good way to increase AT efficiency and car driving power.  相似文献   

14.
通过田间观察,采用TTC法、联苯胺-过氧化氢法、花粉-胚珠比等方法,对黄蜀葵的花部特征、花粉活力、柱头可授性、繁育系统进行了研究.结果表明:黄蜀葵花为两性花,单花开花期为1d,每棵开花历时70 d左右,花粉-胚珠比为83.74±12.956 9,表明其繁育系统类型为兼性自交.柱头可授性在开花初期最强.花朵即将开放与开花初期花粉活力最高、最强,达到90%左右.  相似文献   

15.
对民政部极力推荐的TX社区调查表明,为增加农村公共服务数量、改善结构,建立公共服务供给的长效机制,弥补政府与市场的缺陷,必须发挥社区的平台作用,构筑农村公共服务社区化模式。文章介绍了TX社区公共服务社区化经验,并得出了几点启示:走“内源式”的发展道路,构建有效的公共服务社区化运作机制,积极运用社会资本,合理界定政府与社区权责边界。  相似文献   

16.
A model for the dynamic simulation of dry matter distribution between shoots and roots of a grass forage plant is presented. The objective of this work was to develop a relatively simple mechanistic model of grass growth to simulate the response of assimilate partitioning to variations in light and nitrogen supply based on an original theoretical scheme [Gillet, M., Lemaire, G., Gosse, G., 1984. Essai d'élaboration d'un schéma global de la croissance des gramineés forragères. Agronomie 4 (1), 75–82]. In the model, called MecaNiCAL, C and N assimilates are partitioned between shoots and roots according to the availability of carbohydrate substrate, organ demands and a fixed priority between each demand. Demand related to organ synthesis is described as a function of the plant concentration in the organic nitrogen substrate and temperature. To stay within an acceptable range of complexity, the model is applied only in one vegetative regrowth performed on a hydroponic system with different light and nitrogen nutrition. Carbon and nitrogen acquisition per day are computed by independent submodels, which makes it possible to connect simple and robust functions of carbon assimilation and nitrogen uptake to the partitioning model. Carbon assimilation is simulated for a plant in a canopy, and nitrogen uptake is simulated by a function which depends on nitrogen plant requirements directly related to plant net photosynthesis and the amount of nitrogen available in the nutritive solution. All the assumptions used to describe assimilate partitioning are discussed in relation to knowledge of physiological processes in order to examine closely the limits of the model.  相似文献   

17.
基于三维SWOT模型的国家南繁育制种产业化研究   总被引:1,自引:0,他引:1  
研究国家南繁育制种产业,为产业规划提供参考。引入孙膑和孟子关于"天时、地利、人和"的古典战略思想,改进SWOT分析法,对产业进行全方位分析,找出产业发展的关键问题和内在发展动力,并提出相应的对策建议。经过综合分析,提出3个维度的SWOT矩阵。南繁产业发展的人和X维度虽有南繁科技资源、人才资源和人文资源支持,但欠缺了产学研等产业实体与相关的人才支撑,南繁创新优势未转化为海南科技创新优势,这是南繁产业发展的最大短板;地利Y维度有一定的优势,具备发展南繁种业和科技服务业的自然环境,有面向东南亚的区位优势,有南繁产业创新创业的社会环境,但也面对竞争激烈的市场;天时Z维度有良好的外部环境,纳入了战略性新兴产业,种业产业发展的国际和国内时机较好。南繁产业发展存在的关键问题是南繁资源未转化为海南优势,缺乏产学研用相关的实体,海南种业产业薄弱,没有种业配套优惠政策,发展机遇可能稍纵即逝。南繁产业发展存在种业科研机构与企业成长的内在动力,南繁系统自身建设的内在动力,产业结构优化调整的内在动力,"一带一路"门户建设的内在动力,及南繁产业化发展的内在动力。  相似文献   

18.
利用DH群体动态检测水稻抗褐飞虱数量性状基因位点   总被引:9,自引:0,他引:9  
利用籼粳交珍汕97/武育粳2号F1花培获得的190个双单倍体群体(doubled—haploid population,DH系)及其构建的179个SSR分子标记遗传图谱,通过对DH系群体苗期重复接虫试验和2个不同时期对褐飞虱危害程度进行动态调查,并应用Mapmaker/exp Version3.0和Windows QTL Cartographer V2.0对水稻抗褐飞虱数量性状基因位点(quantative trait locus,QTL)进行动态检测和遗传效应分析。结果表明,在苗期对褐飞虱抗性的检测中,共检测到6个抗性QTL,分别位于第2、3、4、8和10染色体上,各QTL的LOD值分别为2.22-4.64,贡献率为5.04%~13.73%,第3染色体和第4染色体上各有1个OTL的加性效应为正值,表明来自于亲本武育粳2号的这2个位点的等位基因可以提高水稻对褐飞虱的抗性,其余4个QTL的加性效应均为负值,表明来自于亲本珍汕97的这些位点的等位基因可以提高水稻对褐飞虱的抗性。  相似文献   

19.
基于作物生长模型的夏玉米灌溉需求分析   总被引:13,自引:1,他引:13  
用校正后的作物模拟模型(PS123模型)和河北曲周县1966~1999年的逐日气象资料为依据,分析了当地夏玉米的需水量和优化灌溉方案.结果表明,该地区玉米生长季灌溉需水量的年际变异高达80%以上.用模拟的蒸散量计算的1999玉米水分利用效率一般在17~25kg*hm-2*mm-1之间,雨养条件下的水分利用效率较高,可达29kg*hm-2*mm-1.在引入灌  相似文献   

20.
The archtecture and characteristic of digital matched filter circuit used for PN code synchronization are introduced and the method of PN code serial search acquition based on DMF has been researched in AWGN channel.Furthermore the detection probability and false alarm probability are derived for different correlation time(partitive period or whole period).Finally,the results of calculation and emulation are given in order to be employed as useful theoretical bases for reserching the acquisition performance of digital matched filter.  相似文献   

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