室温平衡顶空气相色谱法测定水中苯系物影响因素的研究

对室温下用顶空气相色谱法测定水中苯系物的影响因素进行了研究 ,结果表明 ,室温平衡顶空气相色谱法简单易行 .随着样品浓度的增高 ,平衡时间缩短 ;气液平衡瓶体积增大 ,平衡时间加长 ;同一瓶样品重复进样次数不能多于 2次 ;适宜的气液体积比为 1∶

室温平衡顶空气相色谱法测定水中挥发性卤代烃影响因素的研究

对室温下用顶空气相色谱法测定水中挥发性卤代烃的影响因素进行了研究 ,结果表明 ,随着样品浓度的增高 ,平衡时间缩短 ;气液平衡瓶体积增大 ,平衡时间加长 ;同一瓶样品重复进样次数不得多于 2次 ;适宜的气液体积比为 1∶2。

边缘计算在清洁能源供热系统中的应用分析

介绍了边缘计算设备在分布式清洁能源供热系统中应用的必要性,通过相关案例,分析了通过边缘计算设备实现供热系统中以室温为导向的智能化调控的技术方案、调控策略及实际应用效果,通过边缘计算设备的应用,以达到均衡室温、减小昼夜室温波动、降低能耗的效果。

冰冻红细胞甘油化与去甘油化的改进

目的探讨在冰冻红细胞去甘油化时添加适量的蔗糖溶液,提高红细胞回收率的可行性。方法选择6天内制备的400 ml去白悬浮红细胞60袋,制备成冰冻红细胞,置于-80℃^-65℃的冰箱内保存,在保存4个月后取出解冻去甘油化,并随机分成实验组和对照组,每组各30袋。实验组在去甘油化过程中的第1次洗涤液改用10%的蔗糖溶液,第2次洗涤液改用10%的蔗糖溶液,对照组仍用0.9%的氯化钠溶液进行洗涤,然后分别比较两组的红细胞回收率,甘油残留量和去甘油化过程中的各个洗涤阶段的游离血红蛋白含量。应用SPSS13.0软件,所获数据采用方差分析、t检验。结果两组红细胞回收率比较,P<0.0005;,甘油残留量比较,P>0.05。两组去甘油化第1次洗涤比较,P<0.0005;第2次洗涤、第3次洗涤、第4次洗涤比较,P>0.05。结论冰冻红细胞去甘油化过程中第一阶段的洗涤过程非常重要,对红细胞进行保护,可以显著提高红细胞回收率。

Algorithm of heating temperature for Chongqing's winter greenhouses

Internal temperature is crucial to plant growth in the greenhouse. We investigated the patterns of constructing and managing greenhouses in Chongqing, and developed an algorithm of heating temperature for closed winter plastic greenhouses under the conditions of no man-made illumination, no ventilation and hot wind machine as the heating equipment, which are the most adopted pattern of greenhouses in Chongqing area. The algorithm includes two functions of temperature outside the greenhouse, which calculate the values of the warming estimation coefficient (WEC) and the gap between temperatures inside and outside the greenhouse with the measured data of outside temperature, and then give the value of internal temperature; the heat rating of heating facilities required by a greenhouse can be determined by this algorithm with given values of floor area and internal temperature, measured outside temperature and calculated WEC. Verification of the algorithm demonstrates a desirable accuracy of estimation. Algorithms of computing heating temperature for greenhouses of different constructing and managing patterns and in different geographic conditions can also be derived in a similar way. This research presents a paradigm for developing a feasible method to fit out greenhouses with appropriate heating facilities, aiming at energy efficient and cost efficient production.

Effect on greenhouse gas balance of converting rice paddies to vegetable production

Rice paddies are increasingly being converted to vegetable production due to economic benefits related,in part,to changes in demand during recent decades.Here,we implemented a parallel field experiment to simultaneously measure annual emissions of CH_4and N_2O,and soil organic carbon(SOC)stock changes,in rice paddies(RP),rice paddy–converted conventional vegetable fields(CV),and rice paddy–converted greenhouse vegetable fields(GV).Changing from rice to vegetable production reduced CH_4emissions by nearly 100%,and also triggered substantial N_2O emissions.Furthermore,annual N_2O emissions from GV significantly exceeded those from CV due to lower soil p H and higher soil temperature.Marginal SOC losses occurred after one year of cultivation of RP,CV,and GV,contributing an important share(3.4%,32.2%,and 10.3%,respectively)of the overall global warming potential(GWP)balance.The decline in CH_4emissions outweighed the increased N_2O emissions and SOC losses in CV and GV,leading to a 13%–30%reduction in annual GWP as compared to RP.These results suggest that large-scale expansion of vegetable production at the expense of rice paddies is beneficial for mitigating climate change in terms of the overall GWP.

Optimal scenario balance of reduction in costs and greenhouse gas emissions for municipal solid waste management

To reduce carbon intensity, an improved management method balancing the reduction in costs and greenhouse gas(GHG)emissions is required for Tianjin's waste management system. Firstly, six objective functions, namely, cost minimization, GHG minimization, eco-efficiency minimization, cost maximization, GHG maximization and eco-efficiency maximization, are built and subjected to the same constraints with each objective function corresponding to one scenario. Secondly, GHG emissions and costs are derived from the waste flow of each scenario. Thirdly, the range of GHG emissions and costs of other potential scenarios are obtained and plotted through adjusting waste flow with infinitely possible step sizes according to the correlation among the above six scenarios. And the optimal scenario is determined based on this range. The results suggest the following conclusions. 1) The scenarios located on the border between scenario cost minimization and GHG minimization create an optimum curve, and scenario GHG minimization has the smallest eco-efficiency on the curve; 2) Simple pursuit of eco-efficiency minimization using fractional programming may be unreasonable; 3) Balancing GHG emissions from incineration and landfills benefits Tianjin's waste management system as it reduces GHG emissions and costs.

Nitrogen Balance and Loss in a Greenhouse Vegetable System in Southeastern China

High rates of fertilizer nitrogen (N) are applied in greenhouse vegetable fields in southeastern China to maximize production;however,the N budgets of such intensive vegetable production remain to be explored.The goal of this study was to determine the annual N balance and loss in a greenhouse vegetable system of annual rotation of tomato,cucumber,and celery at five N (urea) application rates (0,348,522,696,and 870 kg N ha-1 year-1).Total N input to the 0-50 cm soil layer ranged from 531 to 1 053 kg ha-1,and N fertilizer was the main N source,accounting for 66%-83% of the total annual N input.In comparison,irrigation water,wet deposition,and seeds in total accounted for less than 1% of the total N input.The fertilizer N use efficiency was only 18% under the conventional application rate of 870 kg N ha-1 and decreased as the application rate increased from 522 to 870 kg N ha-1.Apparent N losses were 196-201 kg N ha-1,of which 71%-86% was lost by leaching at the application rates of 522-870 kg N ha-1.Thus,leaching was the primary N loss pathway at high N application rates and the amount of N leached was proportional to the N applied during the cucumber season.Moreover,dissolved organic N accounted for 10% of the leached N,whereas NH3 volatilization only contributed 0.1%-0.6% of the apparent N losses under the five N application rates in this greenhouse vegetable system.