Progress in the Development of Control Strategies for the SBR Process     

Qing Yang  Shengbo Gu  Yongzhen Peng  Shuying Wang  Xiuhong Liu 《洁净——土壤、空气、水》2010,38(8):732-749

The sequencing batch reactor (SBR) process has shown great success in the treatment of industrial wastewater from intermittent discharge factories and for the treatment of domestic wastewater from medium or small towns. As automation technology has developed, many studies have been conducted to determine the optimal conditions for the SBR process. This review outlines the progress and application of control strategies that have been developed for the SBR process and provides a summary and comparison of the advantages and disadvantages of various control strategies, especially fixed‐time control strategies and various real‐time control strategies. Moreover, an analysis and discussion of novel optimal control methods for biologic nutrient removal are provided. Although previous studies in this field have greatly enriched our understanding of SBR systems, it is clear that many unsolved problems remain. Therefore, a summary of unanswered questions regarding control strategies for the SBR process is provided and future research directions are suggested.  相似文献   

基于多元回归分析的铬污染地下水风险评价方法   总被引：1，自引：0，他引：1  

刘海龙  马小龙  袁欣  穆环玲  冷冰原  洪梅 《吉林大学学报(地球科学版)》2016,46(6):1823-1829

土-水分配系数（K_d）是表征重金属污染物在土壤包气带中迁移能力的重要参数,受污染物质量浓度、pH值、有机质质量分数、铁铝氧化物质量分数等多种因素影响。本文通过实验研究了分配系数与各种影响因素之间的关系,基于多元回归分析方法得到了分配系数与影响因素的关系方程;并以分配系数、泄漏量、土壤孔隙度、初始含水率为风险因子建立了地下水污染风险评价方法。以某工厂铬废液的泄露为案例,采用构建的方法进行地下水污染风险评价。结果表明：该处地下水被污染的风险等级为中等。地下水污染风险评价方法的建立为重金属污染地下水的监测管理提供了一种有效方法。  相似文献   

基础数据库重点要素更新技术的运用     

余树影  苟卫涛  王莉莉 《测绘标准化》2013,(3):38-40

为提高基础地理信息数据库的现势性,需对国家基础地理信息数据库进行整合与更新。结合实际生产经验,较为全面地介绍国家基础地理信息数据库重点要素更新技术的运用、数据的生产流程及在各生产环节中的作业要点,并提出今后作业时要注意的问题,对提高基础数据库重点要素更新工作的速度和质量具有重要的实际意义。  相似文献   

Lake ecosystem dynamics and links to climate change inferred from a stable isotope and organic palaeorecord from a mountain lake in southwestern China (ca. 22.6–10.5 cal ka BP)     

Charlotte G. Cook  Melanie J. Leng  Richard T. Jones  Peter G. Langdon  Enlou Zhang 《Quaternary Research》2012,77(1):132-137

A detailed understanding of long-term climatic and environmental change in southwestern China is hampered by a lack of long-term regional palaeorecords. Organic analysis (%TOC, %TN, C/N ratios and δ¹³C values) of a sediment sequence from Lake Shudu, Yunnan Province (ca. 22.6–10.5 cal ka BP) indicates generally low aquatic palaeoproductivity rates over millennial timescales in response to cold, dry climatic conditions. However, the record is punctuated by two marked phases of increased aquatic productivity from ca. 17.7 to 17.1 cal ka BP and from ca. 11.9 to 10.5 cal ka BP. We hypothesise that these shifts reflect a marked, stepwise lacustrine response to Asian summer monsoon strengthening during the last deglaciation.  相似文献   

Variation in n-alkane δD values from terrestrial plants at high latitude: Implications for paleoclimate reconstruction     

Hong Yang  Weiguo Liu  Qin Leng  Michael T. Hren  Mark Pagani 《Organic Geochemistry》2011,42(3):283-288

The molecular hydrogen isotope composition (δD) of leaf waxes from terrestrial plants is increasingly used to infer hydrological characteristics of ancient high latitude climates. Analysis of the hydrogen isotope composition of n-alkanes (δD_n-alkane) from a global dataset of individual plants growing at low and middle latitudes indicates that plant ecological life form is an important factor in determining the hydrogen isotope fractionation. However, environmental and biological controls of high latitudinal leaf wax δD values are poorly understood because of a lack of δD records from modern flora in these regions. We previously noticed smaller apparent hydrogen isotope fractionations between n-alkanes and environmental water (ε_alk-water) in deciduous trees growing at high latitudes (>59°N; Liu, W.-G., Yang, H., 2008. Multiple controls for the variability of hydrogen isotopic compositions in higher plant n-alkanes from modern ecosystems. Global Change Biology 14, 2166-2177.) To further examine these issues, we measured δD_n-alkane from a variety of plants that inhabit high latitude environments and added critically needed leaf wax δD data from grass and herbs to the existing global δD_n-alkane database. Inclusion of these new data with the existing global dataset (n = 408) confirms plant ecological life form as an important control for leaf wax δD variation for terrestrial plants living at high latitudes. Our results suggest that, while precipitation δD is captured in these high latitude plants, physiological characters such as leaf area, venation pattern and hydraulic system, that enhance transpiration rate during summer growth, may impart δD_n-alkane differences among plants with different ecological life forms.  相似文献   

榕江双偏振雷达与三穗雷达在黔东南一次大暴雨过程中的应用对比分析          下载免费PDF全文

董文韬  毛倩  李舒颖  蔡垚  张超 《中低纬山地气象》2023,47(6):30-36,58

为进一步提升黔东南三穗CINRAD-CD雷达及榕江双偏振雷达产品在山区强降雨过程中的应用能力,提升短临预报预警服务水平,对2部雷达在2022年7月18日大暴雨过程中观测和定量降水估测的差异进行对比分析。结果表明：榕江雷达总体探测能力强于三穗雷达,在黔东南州西部地区,由于雷公山地形阻挡作用,榕江雷达对低层探测能力减弱,在黔东南州中部及以东地区榕江雷达探测能力明显强于三穗雷达;2部雷达探测得到的组合反射率因子峰值与地面分钟降雨量峰值对应关系较好,当降雨减弱时,三穗雷达衰减更明显;三穗单偏振雷达对降水的起止时段及累积降水量的估测能力明显不足,而榕江双偏振雷达QPE产品对降水起止时间及降雨定量估测结果基本接近实况,在业务应用中具有较高的参考价值。  相似文献   

Re–Os molybdenite ages and zircon Hf isotopes of the Gangjiang porphyry Cu–Mo deposit in the Tibetan Orogen     

Cheng-Biao Leng  Xing-Chun Zhang  Hong Zhong  Rui-Zhong Hu  Wei-De Zhou  Chao Li 《Mineralium Deposita》2013,48(5):585-602

The Miocene porphyry Cu–(Mo) deposits in the Gangdese orogenic belt in southern Tibet were formed in a post-subduction collisional setting. They are closely related to the Miocene adakite-like porphyries which were probably derived from a thickened basaltic lower crust. Furthermore, mantle components have been considered to have played a crucial role in formation of these porphyry deposits (Hou et al. Ore Geol Rev 36: 25–51, 2009; Miner Deposita doi:10.1007/s00126-012-0415-6, 2012). In this study, we present zircon Hf isotopes and molybdenite Re–Os ages on the newly discovered Gangjiang porphyry Cu–Mo deposit in southern Tibet to constrain the magma source of the intrusions and the timing of mineralization. The Gangjiang porphyry Cu–Mo deposit is located in the Nimu ore field in the central Gangdese porphyry deposits belt, southern Tibet. The copper and molybdenum mineralization occur mainly as disseminations and veins in the overlapped part of the potassic and phyllic alteration zones, and are predominantly hosted in the quartz monzonite stock and in contact with the rhyodacite porphyry stock. SIMS zircon U–Pb dating of the pre-mineral quartz monzonite stock and late intra-mineral rhyodacite porphyry yielded ages of 14.73?±?0.13 Ma (2σ) and 12.01?±?0.29 Ma (2σ), respectively. These results indicate that the magmatism could have lasted as long as about 2.7 Ma for the Gangjiang deposit. The newly obtained Re–Os model ages vary from 12.51?±?0.19 Ma (2σ) to 12.85?±?0.18 Ma (2σ) for four molybdenite samples. These Re–Os ages are roughly coincident with the rhyodacite porphyry U–Pb zircon age, and indicate a relatively short-lived episode of ore deposition (ca. 0.3 Ma). In situ Hf isotopic analyses on zircons by using LA-MC-ICP-MS indicate that the ε _Hf(t) values of zircons from a quartz monzonite sample vary from +2.25 to +4.57 with an average of +3.33, while zircons from a rhyodacite porphyry sample vary from +5.53 to +7.81 with an average of +6.64. The Hf data indicate that mantle components could be partly involved in the deposit formation, and that mantle contributions might have increased over time from ca. 14.7 to 12.0 Ma. Combined with previous works, it is proposed that the Gangjiang deposit could have resulted from the convective thinning of the lithospheric root, and the input of upper mantle components into the magma could have played a key role in the formation of the porphyry deposits in the Miocene Gangdese porphyry copper belt in the Tibetan Orogen.  相似文献   

加强自然科学基金资助方向引导,推动陆地表层研究深化     

冷疏影  宋长青 《地球科学进展》2013,28(4):509-515

着重阐述了近10年来,为推动陆地表层研究深入发展,国家自然科学基金在重点发展领域、重大研究计划、重大项目、申请代码及学科分类体系细化等层面对资助方向的引导作用。  相似文献   

Advances of Soil Microbiology in the Last Decade in China   总被引：7，自引：0，他引：7  

Song Changqing  Wu Jinshui  Lu Yahai  Shen Qirong  He Jizheng  Huang Qiaoyun  Jia Zhongjun  Leng Shuying  Zhu Yongguan 《地球科学进展》2013,28(10):1087-1105

Soils are fundamental to preservation and sustainability of life-support system on Earth. Soils develop as the most dynamic and complex interface linking atmosphere, hydrosphere, lithosphere and biosphere. Soils harbor enormous diversities of microbial communities as the primary driving forces for global exchanges of matter and energy on our planet. Despite of its profound importance, the invisible soil microbes have for long been underappreciated. In the early 2000s, there has been growing awareness that soil microbiology has attracted huge interest from nonsoil scientists due to the introduction of three domain phylogeny. It is also known as tree of life theory which is widely recognized as the most accurate reflection of the relatedness of all organisms and provides us with a tool to classify and elucidate the largely untapped resource of soil microbial communities. In January 2005, the Department of Earth Sciences of National Natural Science Foundation of China organized a workshop of ‘Soil Biology and Soil Processes’ with focused discussion on soil microbiology research frontiers. The workshop outlined research priorities, cross disciplinary research opportunities, technological needs and potential breakthroughs within soil microbiology. This workshop has witnessed the rapid advances of soil microbiology in soil nutrient transformation, global environmental changes and environmental remediation over the last decade in China. This article will give a brief review on soil microbial researches in the past decade in China, present the status quo of funding system and highlight the challenge and opportunities for future soil microbiology in China.  相似文献   

中国斑岩铜矿与埃达克(质)岩关系探讨   总被引：16，自引：2，他引：14  

冷成彪  张兴春  陈衍景  王守旭  苟体忠  陈伟 《地学前缘》2007,14(5):0-0

对比研究了中国26个主要斑岩铜矿的地球化学特征和年代学,结果表明其中25个矿床与埃达克(质)岩有成因联系,且多数与玄武质下地壳熔融形成的埃达克岩(C型)有关,现有数据表明土屋-延东和普朗斑岩铜矿可能与俯冲板片熔融形成的埃达克岩(O型)有关。容矿斑岩的初始锶值为0.7034～0.7090,均大于洋中脊玄武岩和亏损地幔的初始锶值,多数与EMI的初始锶值接近,推测其源区或源岩主要为玄武质下地壳,少数为洋中脊玄武岩,并受到中、上地壳不同程度的混染,这与两类埃达克岩的源区基本一致。虽然埃达克质岩浆具有形成斑岩铜矿的巨大潜力,但并非所有埃达克岩都能成矿,不同岩体需具体分析。  相似文献