Influence of a New Nano-PE-film on the Greenhouse Environmental Factors

[Objective] This study was to evaluate the impact of a new controlled release anti-drip nano-PE-film （CRANPF） on greenhouse environmental factors. [Method] CRANPF and conventional anti-drip PE film （CLAPF） were compared in terms of air temperature, light intensity and CO2 concentration by the leafy agriculture greenhouse intelligent monitoring system. [Result] Compared to CLAPF, the air temperature rose slower in CRANPF during hot weather and had better photosynthesis efficiency. [Conclusion] Compared with ODLAPF, CRANPF has better perfor- mance and more extensive application prospects.

Influence of misting system on the thermal environment and thermal comfort of seated people in semi-outdoor space in Xi’an,China

In summer,factors such as solar radiation could make semi-outdoor spaces uncomfortable,and the use of misting systems for evaporative cooling is a low-energy improvement measure.To investigate the impact of misting system on the thermal environment and thermal comfort of seated people improvement,a field study was conducted at a semi-outdoor cafeteria in Xi’an.The results indicated that the misting system was capable of reducing the ambient air temperature by 2.4-4.9℃and increasing the relative humidity by 17.1%-17.8%.Participants in misting condition reported lower thermal sensation and higher thermal acceptability,thermal preference,humidity sensation,humidity preference and humidity acceptability.In no misting condition,the upper SET*limit acceptable to 80%of the population was 28.5℃.However,in the misting condition,the acceptable percentage of participants in each SET)interval was more than 90%.When SET)was 22.1-23.7℃,the improvement in human thermal comfort through misting system was not significant.When SET)was 23.7-28.5℃,the misting system significantly improve human thermal comfort.Finally,two control temperature thresholds of the misting system were provided according to the relationship between 80%,the maximum(89.3%)acceptable percentage and the air temperature,which were 30.1℃and 26.5℃,respectively.

High-precision alkali-atom density measurement and control methods using light absorption for dual-beam SERF magnetometers

The alkali-atom density measurement method based on light absorption is highly suitable for a spin-exchange relaxationfree(SERF)atomic magnetometer because of its high-precision measurement and complete nonmagnetic interference.In this study,the optical rotation angle detection system based on polarization balance detection is utilized to realize the alkali-atom density real-time measurement without affecting magnetic field measurement.We discovered that there exists an optimal frequency detuning of the probe light,which offers the highest sensitivity in alkali-atom density measurement and the lowest susceptibility to temperature fluctuations in terms of the scale factor.In contrast to conventional light absorption measurements based on pump light,this method demonstrated a threefold improvement in alkali-atom density measurement sensitivity while remaining immune to ambient magnetic fields and incident light intensity fluctuations.Furthermore,we utilized this method to achieve closed-loop temperature control with an accuracy of 0.04℃.

Numerical Analysis on Ventilating and Air Conditioning Scheme of Shenyang Subway Station

Different cities have different climate conditions and outdoor temperature and humidity, so the scheme of an environment control in subway should be analyzed by considering objective conditions, project cost and operating status. In this paper, a physical and mathematical model is built according to the design of Shenyang subway (line 1), the boundary conditions of the model are defined by the design and experiments, the numerical analysis of ventilating scheme and air conditioning scheme is introduced individually, and the temperature field and air flow field of the two schemes are compared, so that the feasibility of using a ventilating scheme in subway of northeast cities is discussed. Considering comfort and economy, it can be concluded that mechanical ventilation is feasible in subway of northeast cities because the air temperature there is not very high in summer.

Relationship Between Allelopathic Effects and Functional Traits of Different Allelopathic Potential Rice Accessions at Different Growth Stages

In this study,effects of temperature,light and their interactions on allelopathic effects and the functional traits specific leaf area(SLA)and stem mass fraction(SMF)of different allelopathic potential rice accessions at different growth stages were analyzed.The main results were as follows:Allelopathic responses to temperature and light varied with different allelopathic potential rice accessions at different growth stages.With the rise of temperature and the extension of photoperiod,allelopathic effect increased firstly and then decreased at 2–3 leaf stage,but increased constantly at the 4–5 and 7–8 leaf stages in strong allelopathic rice accessions[O.longistaminata,F1(O.longistaminata×RD23),F2(RL159 and RL169)].Temperature had significant impact on allelopathic effect without considering light factors,but light showed little effect on rice allelopathy at the same temperature conditions.The greatest allelopathic effect was attained with moderate temperature and long photoperiod at 2–3 leaf stage in strong allelopathic rice accessions,but all the rice accessions showed weak allelopathic effects at the low temperature condition(15oC/10oC),and the influence of different factors on allelopathy followed a general trend as temperature>leaf stage>light,indicating that among the multiple factors impacting rice allelopathy,temperature was the main factor.Allelopathic characteristics of F1 and F2 to various temperature and light were similar to O.longistaminata,showing that allelopathic genes from wild rice can be expressed in its descendants.Temperature and light also had significant effects on SLA and SMF,and rice allelopathy was closely correlative to SLA in strong allelopathic rice accessions at the 4–5 and 7–8 leaf stages,but there was no correlation between rice allelopathy and SMF at different growth stages.These results suggested that rice adjust the relationship between allelopathy and SLA and adapt to the varied environments,and that high temperature and long photoperiod can enhance rice allelopathic activity.

基于相似日和Optuna-LightGBM的智能控制柜内部环境预警评估方法

针对基于事件驱动的智能控制柜温湿度预测精度较低,无法及时对柜内温湿度异常进行预警的问题,提出了一种基于相似日和Optuna-LightGBM的温湿度预测方法。利用相似日算法选取合适的模型训练数据集,构建基于LightGBM的温湿度预测模型,用Optuna优化模型参数。最后,提出了一种基于曲线拐点检测的预警参数阈值计算方法,分析预测模型得到的温湿度曲线特性,实现温湿度预警。实验结果显示,所提方法的温度预测误差MAPE为0.35%,湿度预测误差MAPE为0.73%,可实现对柜内温湿度的精准预测并及时预警。

Effects of light quality on growth and development of cucumber seedlings in controlled environment

Conventional light sources have been successfully used to cultivate a wide variety of horticultural crops.However,they are of limited use due to uncontrollability of spectra and energy inefficiency.Light-emitting diodes(LEDs)emerged with tremendous potential in controlled environment agriculture due to their energy efficiency,longevity,and spectral specificity,but the effects of different types of LEDs on plant growth and development must be examined.In this study,cucumber(Cucumis sativus L.cv.Zhongnong 26)seedlings were grown under four different lighting treatments that each delivered a photosynthetic photon flux density of 200μmol/m2·s at plant canopy including triphosphate fluorescent lamps(TF),high-frequency fluorescent lamps(HF),white LEDs(WL),and red and blue LEDs(RBL).Cucumber seedlings were grown in a growth chamber at(25.0±1.5)℃with 12-hour light and 12-hour dark for 30 days after sowing,and data were subsequently collected.Seedlings grown under the WL were 45%,12%,and 40%taller than those grown under the TF,HF and RBL,respectively.The leaf area was 23%smaller under the TF than under the HF.The shoot dry weight was 16%-22%lower under the TF than under the other lighting treatments.The transplants grown under the RBL had the lowest root dry weight and root to shoot ratio.The seedling quality index was similar among all the lighting treatments.The LEDs treatment yielded more total dry weight with unit electric power compared to the fluorescent lamps.The chlorophyll content was 13%-15%higher in plants grown under the HF and WL than that under the TF and RBL.Plants grown under the WL and RBL had greater photosynthetic rate,transpiration rate,and stomatal conductance than those grown under the TF and HF.It was concluded that high quality cucumber seedlings can be efficiently produced under the broad-spectrum WL that emit a reasonable amount of blue,green and red light,and the lack of green light and/or high ratio of red to blue light under the RBL may cause undesired plant attributes.

Effects of light intensity and LED spectrum on the medicinal component accumulation of hydroponic Hypericum perforatum L.under controlled environments

Medicinal components of Hypericum perforatum L.plants varies widely due to fluctuations in growth environment and biotic and abiotic contamination during cultivation management.The quality of extracts or preparations is difficult to control because of the unstable raw materials.The aim of this study is to enhance the yield and medicinal component contents of H.perforatum by optimizing lighting factors under controlled environment.H.perforatum plants were hydroponically cultivated for 30 d under 3 levels of photosynthetic photon flux density(PPFD)with 200,300,and 400μmol/(m^(2)·s)using white LEDs(R:B ratio is the ratio of red light to blue light,R:B ratio of 0.9 and 1.8)and white plus red LED(R:B ratio of 2.7).The results showed that PPFD and LED spectrum had significant effects on the growth and accumulation of medicinal components of H.perforatum.Biomass accumulation of stem,leaf,and root increased linearly with the increase of PPFD under each LED spectrum.Fresh weights and dry weights of stem,leaf,and root were significantly higher under a PPFD of 400μmol/(m^(2)·s)with R:B ratio of 0.9 than those of 200μmol/(m^(2)·s),respectively.The relative growth rate and net photosynthetic rate showed linear relationships with PPFD under the same LED spectrum.Total hypericin content,total hyperforin content,and energy yield of hypericin increased with increasing PPFD.Total hypericin content and energy yield of hypericin of P400-L0.9 were 78%and 89%more than those of P400-L2.7,respectively.Total hyperforin content and energy yield of hyperforin of P400-L0.9 and P400-L2.7 were no significant differences.Based on energy efficiency,an R:B ratio of 0.9 of white LEDs with a PPFD of 400μmol/(m^(2)·s)was beneficial to improve medicinal component contents of hydroponic H.perforatum in plant factory with LED lighting.

低温环境对乳化炸药爆炸性能的影响

在低温条件下乳化炸药爆炸性能的下降会严重影响爆破效果,研究药体温度改变后乳化炸药爆炸性能的变化规律具有一定的工程应用价值。为此,设计了一系列乳化炸药药体温度精确控制装置,对药体温度为25、0、-5、-10、-15℃的乳化炸药的爆速、猛度、做功能力及空中爆炸冲击波超压进行测量,并观察乳化炸药的微观结构。实验结果表明:当药体温度由25℃降至-15℃时,炸药的爆速由4227 m/s降至3291 m/s,猛度由13.0 mm降至5.2 mm,做功能力由323 mL降至208 mL,爆炸冲击波超压由284.9 kPa降至115.8 kPa。随着药体温度的降低,硝酸铵析晶量增加,乳胶粒子的局部结构被破坏,致使乳化炸药的微观结构发生变化,爆炸性能降低。低温环境对乳化炸药猛度的影响最大,对爆速的影响最小;随着温度的降低,爆炸性能的降幅增大。在工程应用中,需综合考虑爆炸性能的降幅进行爆破参数设计。

基于非视觉效应的建筑室内人工光环境动态调控方法

以电子信息制造业中的封闭流水线车间作为研究对象,提出了一种基于光非视觉效应及智能优化算法的动态调光方法.首先,基于流水线车间这一建筑室内照明场景,制定了相应动态调光策略,在此基础上结合脉冲宽度调制技术的LED灯具及DIAlux中的光照模拟,建立了光照调控数学模型;其次,为提升蚁狮算法的寻优能力及鲁棒性,提出了基于PWLCM混沌映射、Levy飞行、萤火虫扰动及自适应混合变异机制的改进蚁狮算法,并利用改进蚁狮算法求解光照调控数学模型,实现了光照的最优控制;最后,设计了算法对比实验、光照调控准确度实验及光照模拟实验.实验证明,改进蚁狮算法相较于其他算法寻优能力更强、稳定性更高;动态调光方法可将照度误差控制在5 lux以内,调光准确;动态调光方法在节能的同时有利于缓解工人疲劳.

基于Android手机的温室环境监测与补光控制系统的设计、实现与应用

为实现冬春茬温室作物的自动、智能补光,设计开发并实现了一套基于Android手机的温室环境监测与补光控制系统,用户通过手机APP不仅能够实时获取温室内的环境数据,还能够远程控制补光灯的开启、关闭。并以“京藏香”草莓为试材,通过4个试验重复对比了应用该系统补光对冬春茬温室草莓的影响。结果表明,该系统能够有效完成数据的采集、传输、展示和分析以及补光灯的手动和自动控制,具有性能稳定、实时性好、使用方便、节省人力等特点,而且应用该系统补光可促进草莓增产和早上市,提高收益。

基于SO-BP神经网络的温室环境预测模型研究

由于温室环境中温湿度的调控过程存在滞后响应特性,预测温室环境变化趋势是构建温室精准控制系统中不可或缺的一部分。针对传统神经网络算法在温室预测方面精度不足等问题,提出一种基于蛇优化算法(snake optimizer,SO)优化BP神经网络的温室环境预测方法。试验结果表明,该方法预测15 min内温度的决定系数R^(2)为0.9564,比BP模型、HHO-BP模型分别提高14.87%、2.19%,平均绝对误差MAE、平均绝对百分比误差MAPE、均方根误差RMSE值分别为0.4813、2.2378、0.6729;预测15 min内湿度的R^(2)为0.9821,比BP模型、HHO-BP模型分别提高13.12%、2.37%,预测指标MAE、MAPE、RMSE值分别为1.7090、2.5842、2.2838。该模型的预测结果较理想,可用于温室温湿度预测。

设施温室物联网智能测控系统研究

针对温室环境调控中手动控制和阈值条件调控存在调控精度低、参数超调严重等问题,以设施番茄温室为例,研究提出一种基于环境预测的精准调控策略。首先,构建专用物联网“六域”架构,采用MSP430F5438A作为主控模块,设计感知、通信等功能模块。其次,构建SSA-LSTM预测模型实现对温室环境的精准预测,并根据模型预测结果确定环境调控策略,通过PSO-PID控制模型实现对温室风口电机的精准控制。实验结果表明,相较于传统LSTM模型,SSA-LSTM预测模型的MAE降低58.52%,MAPE降低61.68%,RMSE降低63.84%。同时,相较于传统PID模型,PSO-PID控制模型的超调量降低89.99%,调节时间降低59.85%。系统经过实地部署验证,在保持种植品种和农事管理操作一致的情形下,智能调控的温室产量相较于传统温室提升约8.5%,证明了系统的有效实用性。

弱光环境下仓库搬运机器人抓取控制方法

为精准、稳定、可重复地完成抓取动作,研究了弱光环境下基于稳定轻量级网络的仓库搬运机器人抓取控制方法。首先,针对搬运环境弱光图像,基于稳定轻量级编/解码网络提取抓取区域弱光特征并进行融合处理,获得正常光抓取区域特征;其次,在深度分离融合提取层中,通过处理正常光抓取区域特征,重构深层特征,从而恢复特征提取时丢失的细节信息;再次,在网络输出层内输入重构特征,输出仓库搬运机器人手爪的抓取位姿参数;最后,通过手眼标定得到的搬运目标图像,采集相机坐标系与机器人坐标系的坐标转换关系,将抓取位姿参数转换成仓库搬运机器人抓取控制量,完成对仓库搬运机器人的抓取控制。实验证明,该方法可有效提取搬运目标抓取区域特征,并可有效预测仓库搬运机器人抓取位姿,能完成仓库搬运机器人抓取控制,且抓取精度较高。

极端环境下恒温晶体振荡器的传热过程仿真

晶体是恒温晶体振荡器的核心部件,需要保持温度恒定不变,外部环境温度的巨大变化必将影响晶振输出频率信号的稳定性。根据恒温晶体振荡器的工作状态和机制,建立其在稳态下传热过程的数学模型,探究晶体在高低温环境下的热稳定性,重点分析不同环境温度下功率管输出功率对晶体温度的影响,并利用恒温晶体振荡器实际运行过程中的数据进行验证。结果表明通过仿真得到的数据与实测数据基本一致,当环境温度分别为-40℃、25℃和70℃时,要使稳定后的晶体温度恒定为85℃,相应功率管稳定后的输出功率应为3.95 W、1.42 W和0.74 W。通过调节功率管的输出功率来使晶体在极端环境下达到预设温度并保持恒定,进而使晶振有较高的频率稳定度和较低的相位噪声水平,保证高精度的时钟信号输出。

教室健康照明控制设计

结合人体生理节律与照明的关系,依据教室照明设计相关研究成果,提出教室健康照明控制设计要点、控制策略,并对教室健康照明控制系统在满足照明调节人体生理节律的前提下的节能效果进行计算分析。

高原桥墩混凝土抗裂技术研究

高原、高寒、高海拔地区复杂的环境特点,使得桥墩大体积混凝土施工面临巨大的挑战,混凝土配合比设计、施工工艺、养护工艺及智能监测的全过程精细化控制是防止混凝土开裂的重要措施。通过混凝土配合比的优化、施工和养护方法的提升、施工装备的改进,有效克服大温差、低湿度、强风速等恶劣环境下混凝土的开裂难题,为高原、高寒地区桥墩大体积混凝土施工提供可靠的技术和装备保障,创造更大的经济和社会效益。

某纯电动车型的余热热源与空气源热泵控制策略研究

随着纯电动汽车市场的进一步拓展,为了满足北方客户在寒冷天气下的采暖需求,并缓解低温环境下纯电动汽车续驶里程的衰减,需要对纯电动汽车在低温下的整车热管理控制策略进行更加贴合使用场景的优化。通过针对某纯电动车型在低温环境下不同使用场景中余热热泵与空气源热泵热管理控制策略的研究与实车验证,将热泵热管理系统的有效使用环境温度下限从-15℃拓展到了-20℃,并且实现了该车型在-7℃低温环境下CLTC工况续驶里程衰减率达到31.2%的优秀水平。

典型大空间温湿度独立控制系统地面防结露分析

随着我国基础设施建设步伐的加快,涌现出越来越多空间高大、系统复杂的公共建筑。北方地区为更好地保证此类建筑舒适度,夏季多采用地板辐射供冷系统,但实际应用时易出现地面结露风险。本文通过现场测试的方式对青岛胶东机场进行系统研究,分析温湿度独立控制空调系统的典型大空间室内温湿度分布情况,研究影响露点温度的相关因素,并从供水温度设置策略、空调系统设备运行策略等方面进行深入分析,以期为其他大空间降低地板防结露风险提供借鉴和参考。

物联网在多肉植物园艺中的应用

近年来,随着多肉植物园艺的兴起,如何提高管理效率和保证植物生长质量成为业界关注的焦点。以物联网技术为切入点,探讨其在多肉植物园艺中的关键应用、面临的挑战与解决方案以及未来发展方向,旨在为多肉植物的园艺管理提供科学的决策依据,并推动该领域的创新与发展。