期刊文献+
共找到1,804篇文章
< 1 2 91 >
每页显示 20 50 100
Design of Diversified Intelligent Control System for Energy-saving Optimization of Solar Greenhouse in North China
1
作者 Yanmeng HE Baohui MA 《Asian Agricultural Research》 2023年第7期45-50,53,共7页
Intelligent greenhouse can promote the development of modern agriculture, realize the high quality and high yield of crops, and also bring greater economic benefits. In accordance with the climate conditions in northw... Intelligent greenhouse can promote the development of modern agriculture, realize the high quality and high yield of crops, and also bring greater economic benefits. In accordance with the climate conditions in northwest China, a set of intelligent control system for diversified environment of solar greenhouse was designed. The system divides the annual greenhouse control into six stages according to the optimal energy saving. It uses modern detection technology to collect the greenhouse environmental temperature, environmental humidity, soil humidity, CO_(2) concentration and illumination parameters under different working modes. It uses programmable logic control technology to realize the data processing of various parameters and the action control of rolling film, wet curtain fan and other actuators. It uses KingView monitoring software to realize the monitoring and manual control of greenhouse environment parameters. The operation results indicate that the control system runs stably and basically meets the control requirements. 展开更多
关键词 solar greenhouse energy-saving optimization Diversified Control Intelligent control
下载PDF
Design and Development of a Parabolic Trough Solar Air Heater for a Greenhouse Dryer
2
作者 Eric King’ori Isaac N. Simate 《Journal of Power and Energy Engineering》 2024年第9期1-18,共18页
Design and Development of a Parabolic Trough Solar Air Heater (PTSAH) for a Greenhouse Dryer (GD) was done to improve the dryer’s performance. The materials used for the fabrication of the PTSAH included galvanized s... Design and Development of a Parabolic Trough Solar Air Heater (PTSAH) for a Greenhouse Dryer (GD) was done to improve the dryer’s performance. The materials used for the fabrication of the PTSAH included galvanized sheets covered with aluminium foil, an absorber tube made of GI pipe painted matt black to increase heat absorbance at the focal line, mild steel square tubes, shutter plywood, and an axial fan to push air through the absorber tube. Key geometrical parameters used for the design of the PTSAH were a rim angle of 98 degrees, focal length of 0.2608 m, height of 0.3451 m, length of 2 m, and an aperture width of 1.2 m. The PTSAH’s total aperture surface area was 2.4 m2, while its absorber tube surface area was 0.1587 m2. The PTSAH was experimentally tested to establish its thermal performance. It was found that the ambient air recorded an average value of 31.1˚C and that the air heater could increase the air temperature by 45.6˚C above ambient with a thermal efficiency of 5.3%. It can, therefore, be concluded that the PTSAH can significantly improve the performance of a GD by supplying the GD with air at a higher temperature than ambient. 展开更多
关键词 solar Air Heater greenhouse Dryer Parabolic Trough Thermal Performance
下载PDF
The Actuality and Prospect of Meteorological Service Technology for Solar Greenhouse 被引量:2
3
作者 黎贞发 李春 刘淑梅 《Meteorological and Environmental Research》 CAS 2010年第3期112-116,共5页
The solar greenhouse's construction and its demand on meteorological service in the process of production management in China were analyzed,and the current situation of meteorological service on it was summarized.... The solar greenhouse's construction and its demand on meteorological service in the process of production management in China were analyzed,and the current situation of meteorological service on it was summarized.Combined with the trend of related technology,the future development of solar greenhouse meteorological service was prospected. 展开更多
关键词 solar greenhouse Meteorological service ACTUALITY PROSPECT China
下载PDF
Construction of Cucumber Powdery Mildew Early Warning System in Solar Greenhouse Based on Internet of Things 被引量:1
4
作者 吕雄杰 王晓蓉 贾宝红 《Agricultural Science & Technology》 CAS 2016年第12期2873-2876,2884,共5页
ln order to explore the design and construction of cucumber powdery mildew warning system in solar greenhouse, internet of things technology was used to conduct the real-time dynamic monitoring of the incidence of cuc... ln order to explore the design and construction of cucumber powdery mildew warning system in solar greenhouse, internet of things technology was used to conduct the real-time dynamic monitoring of the incidence of cucumber powdery mildew and cucumber growth environment in solar greenhouse. The growth environ-ment included temperature and humidity of air and soil. Logistic regression model was used to construct cucumber powdery mildew warning model. The results showed that humidity characteristic variable (maximum air humidity) and temperature characteristic variable (maximum air temperature) had significant effects on the inci-dence probability of cucumber powdery mildew in solar greenhouse. And it was fea-sible to construct cucumber powdery mildew warning system in solar greenhouse with internet of things. 展开更多
关键词 solar greenhouse CUCUMBER Powdery Mildew lnternet of Things Warning Model
下载PDF
Impact of Illumination and Temperature Performance of Blanket-Inside Solar Greenhouse and CO_2 Enrichment on Cucumber Growth and Development
5
作者 孙潜 崔世茂 +4 位作者 宋阳 杨志刚 董乔 孙世君 伍虹宇 《Agricultural Science & Technology》 CAS 2016年第8期1757-1761,1776,共6页
To evaluate the effects of solar greenhouse with different structure and CO2 enrichment on illumination and temperature performance of greenhouse and cucumber growth and development in the central region of Inner Mong... To evaluate the effects of solar greenhouse with different structure and CO2 enrichment on illumination and temperature performance of greenhouse and cucumber growth and development in the central region of Inner Mongolia, the research used traditional solar greenhouse (A) and blanket-inside solar greenhouse(B), and set 4 treatments: AE (traditional solar greenhouse A with CO2 enrichment), AN (traditional solar greenhouse A without CO2 enrichment), BE (blanket-inside solar greenhouse B with CO2 enrichment) and BN (blanket-inside solar greenhouse B without CO2 enrichment), to explore the influence of cucumber growth, photosynthetic property, quality and yield in different structure solar greenhouses with CO2 enrichment. The results showed that the illumination and temperature in blanket-inside solar greenhouse was superior to traditional solar greenhouse, and the average light intensity in blanket-inside solar greenhouse increased by 21.05%, compared with traditional solar greenhouse. Under the condition of same greenhouse structure, stem height ,average stem diameter, contents of soluble sugar, vitamin C, net photosynthetic rate and yield showed any significant difference between the treatments with CO2 enrichment or not. Under the condition of same CO2 concentration, BE cucumber average stem height, average stem diameter, contents of soluble sugar, net photosynthetic rate and yield in BE was higher than which in AE. Therefore, the optimization in structure of blanket-inside solar greenhouse remarkably improved illumination and temperature property, combining with CO2 enrichment as application technology, there was crucial significance to promote the greenhouse performance and improve the efficiency of greenhouse vegetable production. 展开更多
关键词 solar greenhouse Illumination and temperature performance CO2 Net photosynthetic rate
下载PDF
Characters of Temperature Variation and Minimal Temperature Forecast inside of Solar Greenhouse in Winter in Shouguang City of Shandong Province 被引量:2
6
作者 袁静 李树军 +2 位作者 崔建云 邱刚 李楠 《Agricultural Science & Technology》 CAS 2012年第9期2001-2005,共5页
[Objective] The aim was to improve meteorological service of protected agriculture and to reduce effects of meteorological disasters. [Method] Characters of temperature variation in solar greenhouse and minimal temper... [Objective] The aim was to improve meteorological service of protected agriculture and to reduce effects of meteorological disasters. [Method] Characters of temperature variation in solar greenhouse and minimal temperature forecast models in winter were analyzed based on meteorological data inside and outside of solar greenhouse in winter during 2008-2011, as per correlation and stepwise regression method. [Result] Temperature was of significant changes in solar greenhouse in sunny and cloudy days and the change was higher in sunny days. In overcast days, temperature in solar greenhouse was lower and plants were affected seriously. In addition, the minimal temperature was of good correlation with outside temperature and humidity, temperature and soil temperature in greenhouse. [Conclusion] The minimal temperature forecast model of solar greenhouse is established and the average absolute error of the forecasted minimums in different types of weather was less than 1 ℃ and the average relative error was lower than 10%. 展开更多
关键词 solar greenhouse Temperature Variation characters Forecast model
下载PDF
Estimation of Cucumber Evapotranspiration in Solar Greenhouse in Northeast China 被引量:16
7
作者 ZHANG Zi-kun, LIU Shi-qi, LIU Su-hui and HUANG Zhi-jun State Key Laboratory of Crop Biology/Key Laboratory of Horticultural Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an 271018, P.R.China 《Agricultural Sciences in China》 CSCD 2010年第4期512-518,共7页
The solar greenhouse without heating system has been widely used for vegetable production in Northeast China since the 1980s. The experiment was conducted in the solar greenhouse to study the relationship between evap... The solar greenhouse without heating system has been widely used for vegetable production in Northeast China since the 1980s. The experiment was conducted in the solar greenhouse to study the relationship between evapotranspiration (ET) of cucumber and climatic factors. Reference evapotranspiration (ET0) and pan evaporation (Ep) were applied to determine cucumber evapotranspiration by regression methods. Results showed that the ET of cucumber increased with the increasing of solar radiation, air temperature and vapor pressure. The solar radiation was the most important factor that influences ET among environmental parameters. The determination coefficient (R2) was 0.865 between ET and Ep, higher than that between ET and ET0 (application of a constant vegetation coefficient, R2 = 0.46). The pan coefficient (kp, determined from the ratio of ET to Ep) and the crop coefficients (kc, determined from the ratio of ET to ET0) showed considerable variability and no obvious systematic pattern could be described throughout the study period. Ep was linearly related to ET and 20 cm pan can be well used to determine the water requirement of cucumber under subsurface drip irrigation in this type of solar greenhouse. 展开更多
关键词 EVAPOTRANSPIRATION reference evapotranspiration PENMAN-MONTEITH CUCUMBER solar greenhouse
下载PDF
Anti-solvent engineering for efficient semitransparent CH3NH3PbBr3 perovskite solar cells for greenhouse applications 被引量:3
8
作者 Waqas Siddique Subhani Kai Wang +4 位作者 Minyong Du Xiuli Wang Ningyi Yuan Jianning Ding Shengzhong(Frank)Liu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2019年第7期12-19,共8页
With ideal combination of benefits that selectively converts high photon energy spectrum into electricity while transmitting low energy photo ns for photos yn thesis,the CH3NH3PbBr3 perovskite solar cell(BPSC)is a pro... With ideal combination of benefits that selectively converts high photon energy spectrum into electricity while transmitting low energy photo ns for photos yn thesis,the CH3NH3PbBr3 perovskite solar cell(BPSC)is a promising candidate for efficient greenhouse based building integrated photovoltaic(BIPV)applications.However,the efficiency of BPSCs is still much lower than their theoretical efficiency.In general,interface band alignment is regarded as the vital factor of the BPSCs whereas only few reports on enhancing perovskite film quality.In this work,highly efficient BPSCs were fabricated by improving the crystallization process of CH3NH3PbBr3 with the assistance of anti-solvents.A new anti-solvent of diphenyl ether(DPE)was developed for its strong interaction with the solvents in the perovskite precursor solution.By using the anti-solvent of DPE,trap-state density of the CH3NH3PbBr3 film is reduced and the electron lifetime is enhanced along with the large-grain crystals compared with the samples from conventional anti-solvent of chlorobenzene.Upon preliminary optimization,the efficiencies of typical and semitransparent BPSCs are improved to as high as 9.54%and 7.51%,respectively.Optical absorption measurement demonstrates that the cell without metal electrode shows 80%transparency in the wavelength range of 550-1000 nm that is perfect for greenhouse vegetation.Considering that the cell absorbs light in the blue spectrum before 550 nm,it offers very high solar cell efficiency with only 17.8%of total photons,while over 60%of total photons can transm让through for photosynthesis if a transparent electrode can be obtained such as indium doped SnO2. 展开更多
关键词 CH3NH3PbBr3 SEMITRANSPARENT PEROVSKITE solar cell ANTI-SOLVENT greenhouse
下载PDF
Dual-Roof Solar Greenhouse—A Novel Design for Improving the Heat Preserving Capacity in Northern China 被引量:1
9
作者 Lilong Chai Baoju Wang +2 位作者 Mingchi Liu Zhanhui Wu Yong Xu 《Natural Resources》 2014年第12期681-686,共6页
Dual-roof solar greenhouse, a new style of solar greenhouse, was designed in this study intending to reduce heat loss in cold time and improve land use efficiency in Beijing, the Capital city of China. Designing and a... Dual-roof solar greenhouse, a new style of solar greenhouse, was designed in this study intending to reduce heat loss in cold time and improve land use efficiency in Beijing, the Capital city of China. Designing and applying the dual-roof greenhouse in metropolitan area had dual effects of saving energy and enhancing land use efficiency. According to the monitoring study and analysis conducted in winter of 2012, the averaged night temperature of south room was about 12.1°C in December, which was satisfying for growing average leaf vegetables. Total energy saved by dual-roof in whole winter was quantified as 1.1 × 107 MJ&#46yr-1 (winter), potentially about 37.4 t coal was saved in Beijing area during whole winter-growing period. Considering the application of north room, the land use efficiency was improved by 62.5% in dual-roof solar greenhouse. 展开更多
关键词 Agricultural Resource Dual-Roof greenhouse solar Energy Land Use Efficiency HEAT Storage
下载PDF
The Relationship between Working Conditions and Adverse Health Symptoms of Employee in Solar Greenhouse 被引量:1
10
作者 ZHANG Min WANG Xiu Feng +2 位作者 CUI Xiu Min WANG Jian YU Shi Xin 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2015年第2期143-147,共5页
To determine the correlation between the working environment and the health status of employees in solar greenhouse, 1171 employees were surveyed. The results show the 'Greenhouse diseases' are affected by many fact... To determine the correlation between the working environment and the health status of employees in solar greenhouse, 1171 employees were surveyed. The results show the 'Greenhouse diseases' are affected by many factors. Among general uncomforts, the morbidity of the bone and joint damage is the highest and closely related to labor time and age. Planting summer squash and wax gourd more easilv cause skin pruritus. 展开更多
关键词 The Relationship between Working Conditions and Adverse Health Symptoms of Employee in solar greenhouse
下载PDF
Effects of Light and Temperature on Uptake andDistribution of Nitrogen, Phosphorus and Potassiumof Cucumber in Solar Greenhouse
11
作者 PEI Xiao-bo, ZHANG Fu-man and WANG Liu(College of Horticulture, China Agricultural University , Beijing 100094 , P. R. China) 《Agricultural Sciences in China》 CAS CSCD 2002年第11期1246-1250,共5页
The influence of light and temperature conditions inside solar greenhouse of winter-spring and autumn-winter crop in northern China on uptake and distribution of nitrogen. phosphorus and potassium of cucumber was stud... The influence of light and temperature conditions inside solar greenhouse of winter-spring and autumn-winter crop in northern China on uptake and distribution of nitrogen. phosphorus and potassium of cucumber was studied. The results showed that plant root development and uptake and distribution of N, P and K benefited more from inside light and temperature changes in winter-spring crop. Root volume and root activity increased more rapidly in winter-spring than in autumn-winter. Uptake of total N, P2O5 and K2O increased with plant development in winter-spring, and declined in autumn-winter crop. Distribution of total N, P2O5 and K2O at different part of cucumber at fruit bearing stage was significantly influenced by inside light and temperature of solar greenhouse. Total N, P2O5 and K2O were mainly distributed to leaves and stems at early stage, and increasingly to fruits after fruit bearing. 展开更多
关键词 CUCUMBER solar greenhouse Light and temperature conditions NUTRIENT UPTAKE Distribu-tion
下载PDF
Comparative Experiment on Different Pepper Varieties in Solar Greenhouse in Lhasa Area
12
作者 Shibin WANG Baohai LI +1 位作者 Rongjie ZHU Bin YANG 《Agricultural Biotechnology》 CAS 2019年第2期39-41,共3页
In order to screen the pepper varieties suitable for planting in the solar greenhouse in Lhasa, variety comparison test was conducted to the continuous cropping of pepper in solar greenhouse. The results showed that Q... In order to screen the pepper varieties suitable for planting in the solar greenhouse in Lhasa, variety comparison test was conducted to the continuous cropping of pepper in solar greenhouse. The results showed that Qianlv Tianshi F_1, Oriental Changlong F_1 and Qujiao 1 F_1 had higher yields than the control, and significantly lower root incidence rates than the control. Therefore, the 3 varieties were suitable fro planting in Lhasa. 展开更多
关键词 LHASA solar greenhouse Pepper. VARIETY
下载PDF
Determination and Analysis on Heat of Trapezoidal Soil Wall in Solar Greenhouse
13
作者 Qing BAI Yahong ZHANG +1 位作者 Lixin Sun Meiqi FEN 《Agricultural Science & Technology》 CAS 2017年第12期2596-2602,共7页
Solar greenhouse with trapezoidal soil wall is widely used due to its good heat retaining property and cost efficiency.In this study, solar irradiance, heat flux and the temperature 0.05 and 0.3 m from the inner surfa... Solar greenhouse with trapezoidal soil wall is widely used due to its good heat retaining property and cost efficiency.In this study, solar irradiance, heat flux and the temperature 0.05 and 0.3 m from the inner surface of the wall at the upper,middle and lower measured positions were determined to study the thermal condition of the trapezoidal soil wall in solar greenhouse. The results showed: first, both the solar irradiance and the temperature increased from the upper to the lower measured position. Second, the heat absorption also increased from the upper to the lower measured position. In clear day, the heat absorption at the three measured positions accounted for 31.4%, 32.6% and 36.0% of the total amount of heat absorption of the whole wall. In cloudy day, the heat absorption at the three measured positions were 0.249, 0.370 and 0.440 MJ/m^2, which accounted for 23.5%, 35.0% and 41.4% of the total amount of heat absorption of the whole wall. When P<0.05, the heat fluxes were strikingly different between the upper and lower measured positions. But when P<0.01, the heat flux had no big difference among the three measured positions. Third, in clear day, the heat emission was the biggest at the middle measured position and smallest at the upper measured position. The heat emission at the three measured positions accounted for 27.5%, 36.7%and 35.8% of the total amount of heat emission of the whole wall. And the heat emission between the middle and lower measured position was not strikingly different. In cloudy day, the heat emission was the biggest at the lower measured position and smallest at the upper measured position. The average heat emission at the three measured positions accounted for 26.1%,36.4% and 37.4% of the total amount of heat emission of the whole wall. Fourthly, correlativity, the solar irradiance directly influenced the heat absorption and had close relation with heat emission. And heat emission again had close relation with the temperature in the greenhouse. Solar irradiance directly influences the thermal condition of a solar green house. It is hoped that this study can be referred to optimize trapezoidal structure and to improve the thermal conditions of the solar greenhouse. 展开更多
关键词 solar greenhouse Soil Wall HEAT
下载PDF
Analysis of Variation Characters and Prediction Model of Soil Temperature in Solar Greenhouse
14
作者 JIA Hong XU Wei-gen +1 位作者 PENG Ming-yan SUN Lei 《Meteorological and Environmental Research》 CAS 2011年第1期15-18,共4页
[Objective] The aim was to study the soil temperature changes and its forecast model in greenhouse by solar heat. [Method] Annual and daily variation characters of soil temperature were analyzed in this paper by using... [Objective] The aim was to study the soil temperature changes and its forecast model in greenhouse by solar heat. [Method] Annual and daily variation characters of soil temperature were analyzed in this paper by using the observation data of air temperature out of solar greenhouse and different layers soil temperature in it. The soil temperature (daily maximum, daily minimum and daily mean) forecasting models were also studied. Simulation and test were conducted to the forecast model of soil temperature in the greenhouse. [Result] The annual changes and daily changes of soil temperature of each layer in the greenhouse were in single peak curve. The lower layer temperature changes were smaller than the upper layer. The soil temperature of each layer within the greenhouse was closely related to the relevance of same type temperature outside the greenhouse of the day. Taking the average daily temperature, daily maximum temperature and daily lowest temperature of the day and the day before as forecast factors, soil temperature forecast model of different layer of same type within greenhouse was constructed. The simulation outcome of average daily temperature of each layer within the greenhouse was better than the simulation outcome of highest temperature of corresponding layer, worse than the simulation of lowest temperature of corresponding layer. The highest temperature of lower soil and daily temperature of soil were better than the upper layer. The simulated soil temperature was much more close to the observation when the observation was during 15-30 ℃. In other interval, it was lower than the observation. [Conclusion] The study offered theoretical reference for the growth environment of sunlight greenhouse plantation. 展开更多
关键词 greenhouse by solar heat Soil temperature Changes characters Prediction model China
下载PDF
Energy-saving Technology of Vent in Passive Solar Wall of Rural House of Severe Cold Region
15
作者 Wei Ling Tian-Yu Zhao +1 位作者 Hong Jin Xi-Peng Zhao 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2014年第4期30-36,共7页
This paper aims at solving the problems of low thermal collection rate,inconvenient maintenance,hindering indoor using during the application of passive solar technologies in rural houses in severe cold region.All the... This paper aims at solving the problems of low thermal collection rate,inconvenient maintenance,hindering indoor using during the application of passive solar technologies in rural houses in severe cold region.All these defects prevent the passive solar houses' further development. This paper chooses trombe wall,which has higher thermal efficiency of the passive solar house,as research object. The traditional vent is improved into a new type of ventilation device. This improvement overcomes the shortcoming,which traditional vent loses huge heat,and simplifies the construction of vent. Comparing with traditional trombe wall,the energy saving rate is 15. 69%. 展开更多
关键词 severe cold region rural house passive solar wall energy-saving technology of vent
下载PDF
Selection and Design of WSN Node Based on Solar Power in Facility Greenhouse
16
作者 Jianchun WANG Chunyang QIAN +1 位作者 Yan WANG Xuefei ZHANG 《Agricultural Science & Technology》 CAS 2017年第10期1955-1959,共5页
In this study, the green energy saving of greenhouse sensor node is de- signed to reduce the system power consumption and high efficiency. The green renewable solar energy resources are used as the energy source of no... In this study, the green energy saving of greenhouse sensor node is de- signed to reduce the system power consumption and high efficiency. The green renewable solar energy resources are used as the energy source of nodes; the lowenergy consumed and cost effective MSP430 chip is used as the main control chip of the processor unit; the transmission frequency of the wireless transmission unit is 433 MHz, which has the characteristics of low power consumption, high signal strength, long transmission distance and small signal attenuation during the transmission; the power supply system unit is composed of monocrystalline silicon solar panel and high performance rechargeable lithium ion battery. The selection basis of each unit is clarified in detail, and optimization is performed by hardware circuit and software program to further reduce power consumption. The power consumption of the node is calculated by the experiment, and the charging conditions of the solar panel used in the node is tested. The results show that the system can achieve the setting target through the selection and design. 展开更多
关键词 Facility greenhouse Low power consumption WSN node solar energy
下载PDF
Control Technology of Solanaceous Vegetable Diseases in Solar Greenhouse in Shandong Province
17
作者 Dongwen Sun Yanchun Gao +3 位作者 Na Li Yizhe Feng Tianyi Yang Jialing Xu 《Plant Diseases and Pests》 CAS 2021年第2期9-10,15,共3页
The occurrence of major diseases of protected solanaceous vegetables in Shandong Province,including tomato Pythium root rot,tomato Phytophthora root rot,tomato Pythium basal stem rot,tomato stem blight,sweet pepper ro... The occurrence of major diseases of protected solanaceous vegetables in Shandong Province,including tomato Pythium root rot,tomato Phytophthora root rot,tomato Pythium basal stem rot,tomato stem blight,sweet pepper root rot,pepper blight and eggplant stem rot,are studied,and corresponding comprehensive control measures are put forward. 展开更多
关键词 solar greenhouse Solanaceous vegetables DISEASES CONTROL
下载PDF
Study on Photosynthesis of Different Position Leaves of Cucumber in Solar-Greenhouse
18
作者 AIXi-zhen ZHANGZhen-xian +1 位作者 YUXian-Chang XINGYu-xian 《Agricultural Sciences in China》 CAS CSCD 2003年第1期56-61,共6页
The photosynthetic rate (Pn) and carboxylation efficiency (CE) were observed to be the highest in mid-position leaves of cucumber in solar-greenhouse, second in upper and middle-lower position leaves, and lowest in lo... The photosynthetic rate (Pn) and carboxylation efficiency (CE) were observed to be the highest in mid-position leaves of cucumber in solar-greenhouse, second in upper and middle-lower position leaves, and lowest in lower-position leaves. The saturation light of the mid-position leaves was also the highest, while the photo compensation points of the upper, middle and lower position leaves decreased as the leaf-position descended. During the growth period, the Pn of most leaves enhanced as PFD increased. Pn curves of diurnal variation in different position leaves had single-peak which appeared at 12: 00 a. m. As the plant density increased, the PFD of different layer leaves decreased, especially of the lower position leaves. The effect of plant density on the Pn of the upper-position leaves was not visible, but on the light compensation points was obvious. As to lower position leaves, the Pn and saturation light decreased as the plant density increased, but the light compensation points were not obviously affected. Cucumber leaves had certain capacity of adaptation and adjustment to light intensity which expressed as the lower the PFD, the higher the apparent quantum yield (AQY). So the AQY increased as the leaf position descended and plant density increased. 展开更多
关键词 CUCUMBER Leaf-position PHOTOSYNTHESIS solar-greenhouse
下载PDF
Experimental Performance and Neural Network Modeling of a Large-scale Greenhouse Solar Dryer for Drying Natural Rubber Sheets
19
作者 Serm Janjai Jagrapan Piwsaoad +1 位作者 Wanich Nilnont Prasan Pankaew 《Journal of Control Science and Engineering》 2015年第1期48-53,共6页
This paper presents experimental performance and artificial neural network modeling of a large-scale greenhouse solar dryer for drying of natural rubber sheets. The dryer consists of a parabolic roof structure covered... This paper presents experimental performance and artificial neural network modeling of a large-scale greenhouse solar dryer for drying of natural rubber sheets. The dryer consists of a parabolic roof structure covered with polycarbonate sheets on a concrete floor. The dryer is 9.0 m in width, 27.0 m in length and 3.5 m in height. Nine 15-W DC fans powered by three 50-W PV modules were used to ventilate the dryer. To investigate its performance, the dryer was used to dry six batches of natural rubber sheets. For each batch, 750 kg of rubber sheets were dried in the dryer. Results obtained from the experiments showed that drying temperatures varied from 32 ~C to 55 ~C and the use of the dryer led to a considerable reduction of drying time, as compared to the open air sun drying. In addition, the quality of the product from the dryer was high-quality dried products. A multilayer neural network model was developed to predict the performance of this dryer. The predictive power of the model was found to be high after it was adequately trained. 展开更多
关键词 solar energy solar drying natural rubber sheets greenhouse solar dryer ANN model.
下载PDF
Study on Growth and Development and Dry Matter Production of Greenhouse Tomato in North China
20
作者 王停停 温祥珍 +2 位作者 张玲 袁婷婷 李亚灵 《Agricultural Science & Technology》 CAS 2016年第7期1638-1641,1713,共5页
[Objective] This study aimed to investigate the growth and development and dry matter production and allocation of greenhouse tomato in North China. [Method] With tomato cultivar 'Jinguo No.l' as the experimental ma... [Objective] This study aimed to investigate the growth and development and dry matter production and allocation of greenhouse tomato in North China. [Method] With tomato cultivar 'Jinguo No.l' as the experimental material, the ex- periments were conducted in a solar greenhouse located in Taigu, Shanxi (37o25' N, 112o25' E) from March to July, in 2014 and 2015. [Result] The plant height, leaf number, leaf area and dry matter production of greenhouse tomato increased lin- early with the increased days after transplantation, and their growth rates were 2.74 cm/d, 0.32 leaf/d, 70 cm2/d and 9.4 g/(m2.d), respectively. The fruit dry weight also showed a linear relationship with the plant dry weight. After fruit setting, the fruit dry weight was increased by about 0.69 g when the plant dry weight was increased by 1 g. The allocation proportions of dry matter in tomato roots, stems and leaves de- clined significantly from plant flowering to fruiting, while the proportion of fruit dry weight in plant dry weight increased significantly, exceeding 60%. There was a strong linear relationship between dry matter production of tomato and effective cu- mulative temperature (sum of temperature higher than 10 ^(3) in the solar green- house, and the dry matter production was increased by about 0.73 g/m2 when the effective cumulative temperature was increased by one unit. The dry matter produc- tion of tomato plant also showed a strong linear relationship with photosynthetic ac- tive radiation (PAR) in the greenhouse, and about 3.4 g of dry matter was synthe- sized per unit (M J) of PAR. [Conclusion] Extending the growing period and improv- ing the temperature and light conditions could increase the dry matter production of tomato. 展开更多
关键词 solar greenhouse TOMATO Growth and development Dry matter alloca- tion
下载PDF
上一页 1 2 91 下一页 到第
使用帮助 返回顶部