Study of Dynamics of Floodwater Nitrogen and Regulation of Its Runoff Loss in Paddy Field-Based Two-Cropping Rice with Urea and Controlled Release Nitrogen Fertilizer Application

The article deals with the effects of urea and controlled release nitrogen fertilizer （CRNF） on dynamics of pH, electronic conductivity （EC）, total nitrogen （TN）, NH4^＋-N and NO3 -N in floodwater, and the regulation of runoff TN loss from paddy field-based two-cropping rice in Dongting Lake, China, and probes the best fertilization management for controlling N loss. Studies were conducted through modeling alluvial sandy loamy paddy soil （ASP） and purple calcareous clayey paddy soil （PCP） using lysimeter, following the sequence of the soil profiles identified by investigating soil profile. After application of urea in paddy field-based two-cropping rice, TN and NHa＋-N concentrations in floodwater reached peak on the 1st and the 3rd day, respectively, and then decreased rapidly over time; all the floodwater NO3--N concentrations were very low; the pH of floodwater gradually rose in case of early rice within 15 d （late rice within 3 d） after application of urea, and EC remained consistent with the dynamics of NH4^＋-N. The applied CRNF, especially 70% CRNF, led to significantly lower floodwater TN and NH4^＋ concentrations, pH, and EC values compared with urea within 15 d after application. The monitoring result for N loss due to natural rainfall runoff indicated that the amount of TN lost in runoff from paddy field- based two-cropping rice with urea application in Dongting Lake area was 7.47 kg ha^-1, which accounted for 2.49% of urea- N applied, and that with CRNF and 70% CRNF application decreased 24.5 and 27.2% compared with urea application, respectively. The two runoff events, which occurred within 20 d after application, contributed significantly to TN loss from paddy field. TN loss due to the two runoffs in urea, CRNF, and 70% CRNF treatments accounted for 72, 70, and 58% of the total TN loss due to runoff over the whole rice growth season, respectively. And the TN loss in these two CRNF treatments due to the first run-off event at the 10th day after application to early rice decreased 44.9 and 44.2% compared with urea, respectively. In conclusion, the 15-d period after application of urea was the critical time during which N loss occurred due to high floodwater N concentrations. But CRNF decreased N concentrations greatly in floodwater and runoff water during this period. As a result, it obviously reduced TN loss in runoff over the whole rice growth season.

Effects of Different Proportions of Controlled Release Urea and Ordinary Urea on Peanut Yield

[Objectives]To study the effects of different proportions of controlled release urea and ordinary urea on peanut yield.[Methods]A total of 5 treatments were set up according to different proportions of controlled release urea and ordinary urea,randomly arranged in blocks and repeated 3 times.[Results]The test results of field districts showed that different proportions of controlled release urea and conventional urea had different effects on peanut yield.On the basis of applying 50 kg/666.7 m^(2)of calcium superphosphate and 17 kg/666.7 m^(2)of potassium sulfate,13.34 kg/666.7 m^(2)of pure nitrogen was applied.The optimal ratio of controlled release urea to ordinary urea was 75:25,followed by 50:50.The output was 379.83 and 371.83 kg/666.7 m^(2),separately increased by 6.74%and 4.50%compared to the application of ordinary urea.[Conclusions]The combined application of controlled release urea and ordinary urea in peanuts can significantly increase peanut yield compared to just applying ordinary urea.

膜曝气生物膜反应器处理航天生活废水效能研究

针对未来星球基地与长期地外飞行产生废水的处理需求,构建了膜曝气生物膜反应器(MABR),以探究该工艺对含尿液与卫生废水的模拟航天废水的处理效能。通过为期376 d的连续试验,开展了反应器启动和驯化,对含不同体积分数尿液的生活废水、飞行阶段废水的处理效能进行研究。结果表明,对尿液体积分数10%的生活废水,MABR稳定运行时可实现97%的总有机碳(TOC)去除率,以及83%的总氮(TN)去除率;对尿液体积分数40%的生活废水,可实现99%的TOC去除率,以及92%的总氮去除率;对飞行阶段废水,可实现98%的TOC去除率,以及65%的总氮去除率。从反应器的活性污泥中检测到丰富的反硝化细菌以及少量厌氧氨氧化菌。经历驯化后,MABR在286 d内对航天生活废水中碳、氮保持了较高的去除率,从而初步验证了该工艺应用于载人航天生活废水处理的可行性。

制氮机控制系统的设计与实现研究

为实现制氮机的自动化控制,文章对制氮机的原理进行概述,深入分析控制系统的功能需求。其次,针对传感器和执行器的选择与配置,提出合适的方案,确保对关键参数的准确监测和调节。在控制算法的设计上,采用PID(比例-积分-微分)控制方法,提高制氮机的稳定性和输出质量。随后,详细介绍控制系统的硬件和软件实现过程,并进行实验验证与性能评估。通过上述措施,制作一种高性能的制氮机控制系统,满足工业生产和实验室等领域的需求。

常压储罐氮封系统的设计

氮封流程是储罐工艺设计的常用流程,为防止储罐内物料因与进入的外界气体(空气)接触而被污染变质或与外界进入的气体(空气)发生化学和(或)生物反应,常需设置气封系统。储罐设置氮封系统是降低油品蒸发损耗必不可少的重要措施。在石油、化工等行业,储罐是必不可少的储存设备,对储罐进行氮封可以有效减少油品蒸发损耗,提高储罐的使用寿命,避免环境污染等问题。对于不同性质的物料,氮封系统方案需要根据物料性质进行改进。例如,对于轻质油品储罐,需要增加氮气流量,保持储罐内部压力稳定,防止油品挥发;对于高温易结晶的液硫,需要增加氮气流动速度,防止液硫结晶,影响储罐使用寿命;对于顺酐,需要增加氮气流量,减少顺酐受潮,防止产生燃爆事故。基于此,本文主要针对氮封系统设计展开相关探讨分析。

煤矿制氮系统的自动化控制设计与应用

以某煤矿为例,从硬件和软件2个方面优化设计原制氮装置控制系统,以期实现设备的自动化联动,进而分析研究制氮系统的自动化控制应用效果和经济性。

制氮自动化控制系统的设计及监控运行分析

为实现制氮控制系统的智能化控制,提升工作效率,设计了制氮自动化控制系统。该系统组网以S7-300为核心、Profibus-DP为总线,通过Modbus协议获得高低压开关柜的电压电流功率等信号,并增加上位机系统实现数字化监控管理,以实时掌握系统的运行情况。经应用,该监控系统显示直观,能够实现系统的整体自动化控制以及无人值守,操作及维护简单,实时性高。

空分氮循环压缩机组控制研究

为解决空分氮循环压缩机组运行波动过程中的问题,介绍了横河CENTUM CS3000集散控制系统、Tricon TS3000系统平台对林德空分C1461机组的控制及防喘振;结合控制系统、现场仪表及执行单元存在的问题和处理措施,通过技术改造,全面解决了稳定性问题,为机组安全稳定运行提供了强有力的技术支撑,对同类型装置有参考和借鉴意义。

矿井移动式膜分离制氮自动控制系统设计与研究

为提高煤矿制氮系统智能化程度,减少制氮过程中问题发生率,实现制氮系统自主化和独立化,利用移动式膜下分离制氮工艺,设计了以PLC为基础的制氮控制系统方法。通过对自动控制器的硬件与软件两个维度进行系统设计与研究,结果显示,制氮自动控制系统装置可以根据传感器采集到的目标参数值进行检测与处理,实时地智能控制制氮进程,有效地减少运维工作投入力度,简化制氮人工操作步骤,保障设备安全有效地制造所需氮气,提高了制氮效率。

Experimental study on water-saving and emission-reduction effects of controlled drainage technology

Field experiments and laboratory analysis were carried out to determine the effects of controlled drainage（CTD） and conventional drainage（CVD） technologies on drainage volume, concentrations of NH4^＋ -N, NO3^-N, and total phosphorus（TP）, nitrogen and phosphorus losses, rice yield,and water utilization efficiency. Results show that CTD technology can effectively reduce drainage times and volume; NH4^＋ -N, NO3^-N, and TP concentrations, from the first to the fourth day after four rainstorms decreased by 28.7%e46.7%, 37.5%e47.5%, and 22.7e31.2%, respectively,with CTD. These are significantly higher rates of decrease than those observed with CVD. CTD can significantly reduce nitrogen and phosphorus losses in field drainage, compared with CVD; the reduction rates observed in this study were, respectively, 66.72%, 55.56%, and 42.81% for NH4^＋ -N, NO3^-N, and TP. Furthermore, in the CTD mode, the rice yield was cut slightly. In the CVD mode, the water production efficiencies in unit irrigation water quantity, unit field water consumption, and unit evapotranspiration were, respectively, 0.85, 0.48, and 1.22 kg/m^3, while in the CTD mode they were 2.91, 0.84, and 1.61 kg/m^3 din other words, 3.42, 1.75, and 1.32 times those of CVD. Furthermore, the results of analysis of variance（ANOVA） show that the indicators in both the CVD and CTD modes, including the concentrations of NH4^＋ -N, NO3^-N, and TP, the losses of NH4^＋ -N, NO3^-N, and TP, irrigation water quantity, and water consumption, showed extremely significant differences between the modes, but the rice yield showed no significant difference.

Studies on the Mechanism of Single Basal Application of Controlled-Release Fertilizers for Increasing Yield of Rice (Oryza sativa L.)

This paper was to explore the mechanism of single basal application of controlled-release fertilizers for increasing yield of rice （Oryza sativa L.）. Pot trials and cylinder trials were carried out from 2002 to 2005 to study the influences of single basal application of 3 controlled-release fertilizers on the changes of soil available N, root development, senescence and lodging resistance at late growth stages. Results showed that at 30 days after fertilization, single basal application of controlled-release fertilizers coated with vegetal-substance （CRF1） and polymer materials （CRF3） increased soil available N to 12.0 and 147.9%, respectively, in comparison to split fertilization of rice-specific fertilizer （RSF1）. Treatments of the two CRFs obviously benefited the development of root system, resulting in greater rice root weights with extensive distribution and higher root activity. In addition, the two CRF treatments, in comparison to RSF1, enhanced chlorophyll consents of the flag leaves to 9.5 and 15.5%, and soluble protein up to 89.7 and 108.0% respectively. Application of the two CRFs also made the base of rice stems strong and large, declined the proportion of shoot and root, increased root depth index. Though relatively low K rate, single basal application of the CRF3 coated with NH4MgPO4 could also promote the development of root system, enhance root activity and some physiological functions of flag leaves. Based on these results, it was concluded that major mechanisms for increasing rice yield by single basal application of the CRFs should be attributed to grater soil available N supply, superior development of root systems, better nutrient absorption capacity, slower senescence and enhancement of lodging resistance at late stages.

单级硝化反应器处理CELSS尿液废水效能研究

针对环控生保系统(CELSS)中尿液废水的处理与回用需求,构建了单级生物硝化反应器,以完成废水中有机物的矿化处理,并实现对其中的氮素的硝化处理,以便进一步资源化利用。在389 d的试验周期内进行了反应器启动、驯化,并完成对不同浓度尿液废水的处理效能研究,考察了生物反应器对不同尿液浓度废水的有机物矿化、氮素转化性能。对尿液体积分数10%的生活废水,稳定运行时可实现97%的总有机碳(TOC)去除率,97%的硝酸盐转化率,碱度消耗约为34 mg CaCO_(3)/mgN;对尿液体积分数40%的生活废水,可实现99%的TOC去除率,52%的硝酸盐转化率,碱度消耗约为234 mg CaCO_(3)/mgN;对纯尿液,可实现99%的TOC去除率,以及50%的硝酸盐转化率,碱度消耗约为146 mg CaCO_(3)/mgN。从反应器的活性污泥中检测出高丰度的硝化细菌。经历驯化后,硝化反应器在长达261 d内对航天生活废水保持了较高的有机物去除率。对尿液体积分数10%的生活废水,使水力停留时间(HRT)保持278 d;对尿液体积分数40%的生活废水,使HRT保持833 d;可在以上工艺条件下实现较高的硝酸盐转化率,初步验证了该工艺作为载人航天生活废水处理单元的应用潜力。

基于工控云的智能移动充氮系统的研究

本文介绍了一种有别于传统充氮系统的智能移动充氮系统,该系统可通过工控云实现对平房仓的智能化、全自动充氮作业,具有体积小、使用灵活、操作方便、建设和维护成本低、高智能化、高扩展性等优点。

全国疾病预防控制系统蛋白粉中蛋白质能力验证结果分析

目的组织全国疾病预防控制系统蛋白粉中蛋白质测定能力验证项目,评价实验室检测蛋白粉中蛋白质含量的技术能力和水平。方法采用单因素方差分析法评价考核样品的均匀性和稳定性,并向实验室发放蛋白质考核样品;各实验室参照GB 5009.5—2016《食品安全国家标准食品中蛋白质的测定》第一法凯氏定氮法对蛋白质进行检测;对检测结果进行稳健统计分析,通过Z值评定实验室的检测能力。结果全国疾病预防控制系统有48家实验室完成了本项能力验证,蛋白质检测结果满意率为97.9%。结论多数参加实验室检测能力结果满意,表明蛋白粉中蛋白质检测水平总体良好。此次能力验证促进了各参加实验室对该类测试项目检测能力的提高。

充氮气调智能控制管理系统在浅圆仓中的应用

将充氮气调储粮智能控制管理系统应用于浅圆仓储粮,试验了储粮过程中仓内氮气浓度分布及变化、仓内温度变化、杀虫效果,探讨了该体统使用的气密性、成本以及工艺问题。结果表明,充氮气调储粮智能控制管理系统可以确保充进的氮气浓度达到浅圆仓廒所需的工艺浓度要求,破坏害虫及霉菌的生存环境,延缓粮食品质陈化,实现绿色储粮。该系统性能稳定,工艺简单实用,具有先进、安全、高效的特性,能有效控制仓内氮气浓度,减少仓储人员工作量,提高充氮效率。

保鲜运输用液氮充注气调控制系统的设计与试验

为实现对气调保鲜运输厢体内气体成分的自动控制,以液氮充注气调为对象,搭建了液氮充注气调试验平台。设计了基于低温保护优先的气调方案,采用双限值的控制方法,实现了液氮充注气调的自动控制。以香蕉为试验物料,开展液氮充注气调保鲜试验。结果表明:运输厢体气密性对氧气体积分数变化影响较大,气密性差则增加了系统执行机构的工作频率及液氮消耗量;塑料筐和纸皮箱2种香蕉包装条件对液氮充注降氧影响不大;初始温度对液氮充注的降氧时间影响较大,初始温度高时降氧时间短,初始温度低时降氧时间长;系统实现了以温度优先的气调控制策略,系统工作稳定性良好。上述研究为开发液氮充注气调保鲜运输车提供了参考。

Time-optimal control for hybrid systems based on the nitrogen-vacancy center

Fast and high fidelity quantum control is the key technology of quantum computing. The hybrid system composed of the nitrogen-vacancy center and nearby Carbon-13 nuclear spin is expected to solve this problem. The nitrogen-vacancy center electron spin enables fast operations for its strong coupling to the control field, whereas the nuclear spins preserve the coherence for their weak coupling to the environment. In this paper, we describe a strategy to achieve time-optimal control of the Carbon-13 nuclear spin qubit by alternating controlling the nitrogen-vacancy center electron spin as an actuator. We transform the qubit gate operation into a switched system. By using the maximum principle, we study the minimum time control of the switched system and obtain the time-optimal control of the qubit gate operation. We show that the X gate and Y gate operations are within 10μs while the fidelity reaches 0.995.

分程控制在焦炉煤气制氢装置中的应用

阐述了分程控制的实现方式、类别及应用场景;以焦炉煤气制氢装置氮气减压系统作为分析对象,介绍了低压氮气应用范围和控制要求,通过不同分程控制方案的对比,选择了固定分程点的控制方案;经过氮气减压系统放空测试,证明选择的分程控制方案满足工艺生产运行要求;总结了氮气减压系统分程控制设计的安全设置要求和注意事项,为分程控制在公用工程系统中应用提供参考。

灌排调控的稻田排水中氮素浓度变化规律

基于农田排水氮素浓度及湿地进出口断面总氮(TN)、氨态氮(NH4+-N)、硝态氮(NO3--N)浓度的监测,研究了灌溉排水措施以及沟塘湿地对农田排水中氮素浓度变化的影响。结果表明,控制灌溉的水稻全生育期稻田排水中TN、NH4+-N和NO3--N浓度分别较常规灌溉处理低12.08%、20.33%和13.51%;控制排水处理下稻田排水中TN、NH4+-N和NO3--N浓度分别较常规排水处理低2.21%、7.08%和20.92%;湿地出口水体中TN、NH4+-N和NO3--N浓度分别比入口降低了16.8%、14.4%和50.9%,湿地水体中TN、NH4+-N、NO3--N浓度随时间近似服从指数函数衰减趋势。控制灌溉、控制排水及沟渠塘湿地系统的调控措施对农田排水中氮素的净化效果比较显著。