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基于BP神经网络算法的温室番茄CO2增施策略优化 总被引:6,自引:0,他引:6
CO2浓度是植物光合作用的主要原料之一,确定植株生长阶段的最适CO2浓度需求量,对日光温室内CO2浓度调控具有重要意义。以开花期番茄植株为研究对象,将定植后的番茄分为4个CO2浓度梯度处理组,其中,C1、C2、C3处理组CO2增施摩尔比分别为(700±50)、(1 000±50)、(1 300±50)μmol/mol,CK处理组为温室内自然状态下CO2摩尔比(约450μmol/mol)。实验利用无线传感器网络节点实时监测温室环境因子,包括空气温湿度、光照强度和CO2浓度;利用LI-6400XT型便携式光合速率仪进行光合日动态和环境因子交互影响实验测定。光合日动态组间差异性研究表明,对开花期番茄增施1 000~1 300μmol/mol的CO2时,可使番茄单叶净光合速率提高约37.13%~40.42%。以环境因子为输入参数,建立基于BP神经网络的光合速率预测模型,用于不同CO2浓度梯度下的光合日动态预测。结果表明,模型训练集和测试集的相关系数分别为0.98和0.93,预测精度较高;C1、C2、C3和CK处理组的日动态预测相关系数分别为0.96、0.94、0.78和0.96,与实测结果吻合度较高且相对误差较小,因此该模型可以为可变环境下的番茄光合日变化动态预测提供依据。 相似文献
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生物质流化床气化反应过程数值模拟 总被引:1,自引:0,他引:1
建立了二维生物质流化床气化炉模型,模型包括气相质量、动量和能量守恒,热解过程动力学采用一步反应模型,气固均相与非均相反应采用物质输送模型,重点考察了颗粒在炉内的运动和热解气化过程,分析了温度和当量比对燃气组分的影响,并对模拟结果与实验结果进行对比验证.结果表明:颗粒在炉内的运行时间约为2.15s,0.8s左右时颗粒进入稳定的流化环境;CO2和CH4摩尔分数沿y轴方向逐渐将低,而CO和H2摩尔分数沿y轴方向不断增加.在不同温度和当量比条件下,模拟所获得的H2、CO、CH4和CO2摩尔分数与实验结果具有良好的一致性. 相似文献
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利用沃氏甲烷球菌将CO转化成CH4的研究初报 总被引:2,自引:0,他引:2
本实验对沃氏甲烷球菌(M.voltae)利用CO产甲烷进行了初步研究.实验结果表明该菌能利用H2/CO产甲烷,也能利用CO产甲烷.该菌利用H2/CO平均每24小时产甲烷0.76
mL·mg-1(细胞湿重);利用CO平均每24小时产甲烷0.11 mL·mg-1(细胞湿重),仅为H2/CO实验组的1/7.检测中间代谢产物发现该菌在利用CO产甲烷时有中间产物H2和CO2的生成;在利用H2/CO产甲烷时未产生中间产物CO2. 相似文献
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胡柚皮总黄酮超临界CO2萃取工艺 总被引:1,自引:0,他引:1
为研究超临界CO2萃取胡柚皮总黄酮的工艺,在夹带剂试验和单因素试验的基础上,采用四因素三水平正交试验设计,以萃取压力、萃取温度、动态萃取时间、CO2流量为考察因素,优选了超临界CO2萃取胡柚皮总黄酮的最佳工艺.结果表明:该试验无需使用夹带剂,各因素对得率的影响大小依次为:CO2流量、萃取时间、萃取压力、萃取温度.最佳萃取工艺条件为:萃取压力35 MPa,萃取温度45℃,静态萃取40 min后动态萃取60 min,CO2流量3 L/min,此条件下胡柚皮总黄酮的得率可达1.01 mg/g. 相似文献
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温室气体中最常见的就是CO2,它对于作物进行光合作用来说却是必不可少的.然而设施栽培中因CO,的不足已经成为限制设施栽培作物生长发育最不易控制的主导因素.由此,如何调控大棚内的CO2浓度,使之满足作物光合作用的需要,达到提高产量,改善品质的目的,已成为农业设施栽培发展迫切需要解决的问题.
据测,温室中的CO2仅稳定在350ppm左右,这就大大地限制了作物的生长潜能,造成作物生长环境的资源浪费.实验表明,当环境中的CO2浓度达到1000~1500ppm时,可以使作物比平时增产达到20%左右,且品质也有明显提高. 相似文献
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《Journal of Agricultural Engineering Research》1998,69(3):249-254
A model to represent the discolouration of dried powder of carrots as a function of temperature was developed. Two types of carrots, Asian and European, containing large amount of lycopene and β-carotene, respectively, were tested. The dried powder was stored under an atmosphere with O2and at three different temperatures, 5,20 and 35°C. The surface colour of the powder was monitored during storage by a Hunter colour ratioa/b. In the proposed model, the rate of oxidation was assumed to be represented by the product of the fraction of concentration of oxidized pigment at arbitrary time and a specific rate of oxidation of pigment. The rate parameters in the proposed model were calculated by fitting the experimental data with smooth curves by trial and error at the end of the induction period but before discolouration took place. The frequency constant and activation energy, expressing the temperature dependence of the rate parameters, were expressed by the Arrhenius relation. The simulation results of a Hunter colour ratioa/bof dried powder at 25°C showed good agreement with the experimental data, suggesting that the proposed model was effective for the prediction of discolouration of dried powder of both types of carrot. The use of the induction period in the manner described may enable the shelf life of dried powder to be predicted. 相似文献
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感官检验棉花的品级,这是农村常见的一种检测手段.它的一个主要特点就是存在不确定性.这是由于检验员的品级检验水平存在一定的差异,其中有很多因素制约着检验的结果.文章对影响感官检验结果的因素进行了系统的分析. 相似文献
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The fractional outflow rate of water from the rumen, measured as the rate of disappearance of the chromium complex of ethylenediamine tetra-acetic acid, was related to a number of dietary factors. A multiple regression equation was derived which expressed fractional outflow rate as a function of the intakes of dry matter, ash, acid-detergent fibre and crude protein.The data analysed consisted of 243 observations for sheep on 59 diets, including forage, concentrate and mixed diets. The ranges covered by the data were: fractional outflow rate 0.7–3.6 day?1; dry matter intake 560–1400g/day; ash 4–30%, acid-detergent fibre 7–41%, crude protein 5–26 % of dry matter; there were no observations for sheep of less than 34 kg liveweight.The equation accounted for 56·3 % of the total variance. Between-sheep variance could not be calculated for the whole of the data but was undoubtedly substantial since, for a sixth of the data, it was known to account for 38 % of the total variance. 相似文献
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从灾害经济学的角度探讨了城镇供水优化调度的必要性和可能性,认为在缺水不可避免的情况下,对供水进行优化调度可以减小缺水带来的损失,产生较好的减灾效益,特别是可以大大减小严重干旱的灾害效应。并根据水资源的特性,提出了缺水损失的计算模式以及优化调度的原则和方法。 相似文献