土地利用/覆被变化对土地生态系统有机碳库的影响——以吉林省通榆县为例

土地利用/覆被变化对陆地碳循环影响显著.文章基于实地采集的土壤、植物样品的测试数据和1989、2004两年8月陆地卫星TM遥感影像数据,采用生态系统类型法分析吉林省通榆县1989-2004年耕地、林地、草地、盐碱地、沙地等11 种地类之间土地利用变化对土地生态系统有机碳库的影响.计算结果表明1989-2004年通榆县土地生态系统有机碳库共损失了3.18 TgC(1Tg=106t),年均损失约为0.265 Tgc.其中,湿地、草地有机碳库分别损失5.54 TgC和3.71 TgC,盐碱地面积的增加导致有机碳库损失4.75 TgC.林地面积增加和沙地面积减少分别使有机碳库增加了4.58 TgC和3.75 TgC.研究区总体上为一个碳失汇,草地退化、湿地萎缩、土地沙化和盐碱化造成了有机碳库的碳损失,而植树造林、草地植被的恢复和重建等活动则可以显著增加土壤有机碳储量.该研究对于评估自然环境与人为活动影响下,特别是大规模土地整治与生态修复对土壤有机碳的增汇潜力和固碳效应的影响具有重要的理论意义和应用价值.     

农田土壤自养微生物碳同化潜力及其功能基因数量、关键酶活性分析

研究农田土壤自养微生物碳同化潜力,对全面认识农田生态系统碳吸收和碳储存有着重要意义.选取6种典型农田土壤,通过14C连续标记示踪技术结合密闭系统模拟培养,量化了土壤自养微生物碳同化潜力及其向土壤活性碳库组分转化,同时结合分子生物学技术及酶学分析方法,探讨了不同土壤自养微生物细菌固碳功能基因(cbbL)丰度及关键酶(RubisCO)活性.结果表明,土壤自养微生物具有可观的CO2同化潜力,在本实验条件下,全球每年表层(0~20 cm)土壤通过自养微生物的同化作用可固定的碳为0.57~7.3 Pg.供试土壤的14C土壤有机碳(14C-SOC)含量范围为10.63~133.81 mg·kg-1,而14C可溶性有机碳(14C-DOC)、14C微生物生物量碳(14C-MBC)含量范围分别为0.96~8.10 mg·kg-1、1.70~49.16 mg·kg-1.土壤可溶解性有机碳(DOC)、微生物量碳(MBC)和SOC的更新率分别为5.07%~14.3%、2.51%~13.12%和0.09%~0.64%.土壤细菌cbbL丰度范围为2.40×107~1.9×108copies·g-1,且RubisCO酶活性(CO2/soil)范围为34.06~71.86 nmol·(g·min)-1.相关分析表明,土壤14C-SOC与14C-MBC及RubisCO酶活性均呈极显著正相关关系(P<0.01).说明土壤对大气CO2的同化作用主要是由自养微生物参与的同化过程,且较高的RubisCO酶活性意味着较高的自养微生物CO2同化潜力.     

大空间仓库堆垛特性对水炮雾状射流灭火性能影响的实验研究

大空间堆垛储物仓库的消防安全日益引起重视,自动消防炮灭火系统已广泛应用其中。堆垛物遮挡和柱状射流特性对水炮灭火有影响,雾状射流由于覆盖区域增大可提高灭火效率,堆垛特性可能会影响雾状射流灭火效果,目前缺乏相关研究。通过预喷水、布水和灭火实验研究大空间仓库堆垛特性对水炮雾状射流喷水强度分布和灭火性能的影响。结果表明:该文所研究自动消防炮(安装高度8m,雾化角度90°)在5m至15m射程间,能够有效扑灭或控制大空间仓库火灾;喷水强度和有效保护面积随射程的增大而减小,仓库危险级Ⅰ级和Ⅱ级储物高度为3.0m-3.5m时有效保护面积在5m射程处分别为27.5m2和25.5m2;堆垛高度一定时存在最小堆垛间距,小于此值时火灾将不能被扑灭或控制。     

大型LNG储罐灾难性破裂后LNG扩散范围分析

采用DNV公司的SAFETI 6.42软件,对容量为16×104m3 LNG储罐灾难性破裂后LNG扩散范围进行了仿真分析.     

Pd/CZ/Al2O3催化剂的制备、表征与三效催化性能

以共浸渍法制得的氧化铝负载铈锆固溶体为载体,并浸渍贵金属Pd得到了Pd/CZ/Al₂O₃催化剂.实验结果表明,该催化剂在老化前后都表现出良好的三效催化活性,新鲜样品Pd/CZ/Al₂O₃活性与Pd/CZ相当,老化后样品前者优于后者.结合XRD,BET,TPR等表征手段,讨论了Pd/CZ/Al₂O₃的催化活性特别是高温老化后活性与其组成结构之间的内在关系,揭示了其老化后仍具有较高活性的主要原因在于保持了Pd与CZ/Al₂O₃复合载体之间的强相互作用(SMSI).     

BioDopp中试系统强化脱氮除磷及微生物菌群分析

为论证存量市政污水处理厂同时提标和扩容的可行性,以北京市某低C/N的生活污水处理中心提标扩容改造项目为依托,采用基于BioDopp工艺的IFAS-微氧AO技术构建了中试系统,考察了该工艺对有机物和氮磷营养物的去除效能及其微生物菌群特征,并核算了其经济效益.试验结果表明,基于实际污水污染物浓度较低,通过逐渐提高处理水量以提高负荷的启动策略是可行的.中试装置启动8d后,系统稳定运行,出水COD、NH₃-N、TN和TP浓度分别为18.9,0.4,8.3和0.7mg/L.高通量测序结果表明,该工艺强化了对功能菌,尤其是反硝化聚磷菌的富集,其总相对丰度7.6%,达接种活性污泥的23.6倍.该系统HRT 16.6h,仅为该污水处理中心原工艺(27.2h)的61.0%,节地优势显著;生物除磷效率高,节省药剂投加成本;且微氧控制和空气提推回流大幅降低了污水处理的曝气和回流能耗,由此可见,BioDopp工艺可用于紧凑型污水处理厂建设,是污水处理厂高效节能减碳利器.     

浅谈油品储运系统静电灾害的预防与控制

结合油品储运系统的工作特点,通过分析静电灾害发生的过程,得出产生静电灾害事故的4个必要条件,并从如何控制每个条件的形成出发,分别提出了针对性的防控措施。     

Evaluation of RothC model using four Long Term Fertilizer Experiments in black soils, India

Carbon content in soils changes depending on the land use system, type of management practice and time. There is an increasing concern about the soil quality vis-à-vis organic carbon content in soils due to global warming and enhanced CO₂ concentration in the atmosphere. This has led to estimate carbon stock in soils at global and regional levels. The objective of the present study was to evaluate RothC model to estimate total organic carbon (TOC) changes under four long term fertilizer experimental sites representing sub-humid moist (Sarol and Nabibagh), sub-humid dry (Panjri) and semi-arid (Teligi) climate in India. The plant carbon input rate was calibrated using organic carbon and other soil parameters using RothC. The results showed that RothC could simulate changes in TOC in two contrasting eco-sites for surface soil layers. The root mean square error (RMSE) considered as modelling error ranged from 11.50 to 15.01, 4.70 to 11.60, 2.14 to 6.52 and 1.45 to 13.74 in the surface layers of Sarol, Nabibagh, Panjri, and Teligi sites, respectively. The simulation biases expressed by M (relative error) by Student‘t’ value for all the treatments at these sites were non-significant with two exceptions. Observed trends in TOC consist of an increase for all the four treatments in the sub-humid site of Sarol and Nabibagh; while manures alone or in combination increase TOC appreciably in Teligi and Panjri. TOC remained, however, almost similar over years for the control (no fertilizer or manure) and NPK treatments in all the four sites. Analysis of RothC output data showed that this model could be used as a tool to arrive at different threshold values of rainfall to influence decomposition rate modifier and thus to find out rate of organic carbon sequestration in various bioclimatic systems.     

神农架大九湖泥炭地碳储量估算及固碳能力研究

通过对神农架大九湖泥炭地进行野外调查和长期观测,采用经验公式和实验室分析方法,计算了神农架大九湖泥炭地土壤有机碳含量和有机碳储量,并对2016-2018年神农架大九湖泥炭地的固碳能力特征进行了分析.结果 表明:在0～100 cm深度范围内,神农架大九湖泥炭地土壤有机碳含量的变化范围为282.90～516.10 g/kg...     

Treatment of Sulfate/Sulfide-Containing Wastewaters Using a Microbial Fuel Cell: Single and Two-Anode Systems

The microbial fuel cell (MFC) was employed to convert reductive potential in sulfate-laden wastewaters to electricity via reducing sulfate to sulfide by sulfate-reducing bacteria and then oxidizing sulfide to sulfur by exoelectrogens. The excess sulfide presented in the anodic solution inhibited the activities of functional strains in MFC. This study proposed the use of a two-anode system, with a sulfate-reducing bacteria anode and an exoelectrogen (C27) anode in the anodic cell, to efficiently convert reductive potential of sulfate into electricity. The microbial community of sulfate-reducing bacteria anode and the electrochemical characteristics of the studied MFCs were reported.