海绵城市规划指标分解案例研究——以北京A新城为例

设计指标分解是海绵城市规划设计的重难点,但目前并没有统一的标准来指导实践.为探索海绵城市规划指标分解方法,以A新城海绵城市专项规划为例,将年径流总量控制率、控制容积作为控制性指标,下沉式绿地率、透水铺装率、绿色屋顶率和调蓄容积作为引导性指标,结合建设情况、汇水面种类及构成情况等条件,利用海绵城市规划设计辅助计算软件加权...     

结构与效率因素的节能效果分析——以北京为例

近年来,北京市能源强度呈现出不断下降的趋势,准确计量影响能源强度变动的各因素所产生的节能效果,可为未来进一步挖掘节能潜力提供参考。论文采用能源强度变化的完全分解模型,以1985—2007年为样本期,对影响北京市能源强度变化的结构因素和效率因素进行了计量。结果表明:在整个样本期内,效率和结构因素都对北京市的节能产生了正向作用,并且效率因素的节能效果大于结构因素。分阶段分析显示,2000年以后,结构节能效果表现出逐渐增强的趋势。由此可见,目前北京市的效率节能效果良好,结构节能效果有所发挥,但仍有潜力可挖,并且最大潜力在于工业部门内部结构的变化。     

A comparative investigation of NdSrCu_(1-x)Co_xO_(4-δ) and Sm_(1.8)Ce_(0.2)CU_(1-x)Co_xO_(4-δ) (x: 0-0.4) for NO decomposition

A series of single-phase T-structured NdSrCu_(1-x)Co_xO_(4-δ) with oxygen vacancies and T'-structured Sm_(1.8)Ce_(0.2)Cu_(1-x)Co_xO_(4-δ) (x:0-0.4) with oxygen excess were prepared using ultrasound-assisted citric acid complexing method, and characterized by means of techniques such as thermogravimetric analysis and NO temperature-progranuned desorption (NO-TPD). The catalytic activities of these materials were evaluated for the decomposition of NO. It was found that the NdSrCut_xCoxO4_b catalysts were of oxygen vacancies whereas the Sm_(1.8)Ce_(0.2)CU_(1-x)Co_xO_(4-δ) ones possessed excessive oxygen (i.e., over-stoichiometric oxygen); with a rise in Co doping level,the oxygen vacancy density of NdSrCu_(1-x)Co_xO_(4-δ) decreased while the over-stoichiometric oxygen amount of Sm_(1.8)Ce_(0.2)CU_(1-x)Co_xO_(4-δ)increased. The NO-TPD results revealed that NO could be activated much easier over the oxygen-deficient perovskite-like oxides than over the oxygen-excessive perovskite-like oxides, with the NdSrCuO_(3.702) catalyst showing the best efficiency in activating NO molecules. Under the conditions of 1.0% NO/helium, 2800 hr~(-1), and 600-900℃, the catalytic activity of NO decomposition followed the order of NdSrCuO_(3.702)> NdSrCu_(0.8)Co_(0.2)O_(3.736) > NdSrCu_(0.6)Co_(0.4)O_(3.789) > Sm_(1.8)Ce_(0.2)Cu_(0.6)Co_(0.4)O_(4.187)> Sm_(1.8)Ce_(0.2)Cu_(0.8)Co_(0.2)O_(4.104)> Sm_(1.8)Ce_(0.2)CuO_(4.045), in concord with the sequence of decreasing oxygen vacancy or oxygen excess density. Based on the results, we concluded that the higher oxygen vacancy density and the stronger Cu~(3+)/Cu~(2+) redox ability of NdSrCu_(1-x)Co_xO_(4-δ) account for the easier activation of NO and consequently improve the catalytic activity of NO decomposition over the catalysts.     

Mg(BH_4)_2和MgH_2对RDX热分解特性的影响

在黑索今(RDX)中加入具有高热值的金属氢化物(Mg(BH4)2和MgH2)有望提高RDX的爆炸性能,但同时给RDX的安全使用带来挑战。为了探索RDX与这2种金属氢化物的相容性与安定性,采用差示扫描量热法(DSC)研究Mg(BH4)2和MgH2对RDX热分解性能的影响,并由DSC得到的数据计算动力学参数,参照GJB770B—2005的方法分析这2种金属氢化物与RDX的相容性和安定性。结果表明,加入Mg(BH4)2使RDX的表观活化能从159.22 kJ/mol增加至180.27 kJ/mol,加入MgH2使RDX的表观活化能降低至133.69 kJ/mol;Mg(BH4)2与RDX的相容性为1级,MgH2与RDX的相容性为3级,加入Mg(BH4)2使RDX的安定性有所提高,加入MgH2降低了RDX的安定性。因此,在将MgH2作为RDX的高能添加剂以前,必须首先提高其与RDX的相容性以保证试验和存储过程的安全。     

鄱阳湖双退区受损湿地植被恢复对水质的影响

退化湿地的植被恢复有助于提高湿地生物多样性和净化水体功能。通过监测鄱阳湖双退区（湿地）生态恢复过程中前后水质变化,分析了不同植被覆盖率和植物残体分解对水质的影响。结果表明,在植物生长期间,湿地水体TN质量浓度下降65.4%～71.3%,NO3--N也呈较大幅度下降,并能降低水体TP浓度水平;高植被覆盖增加水体叶绿素质量浓度水平,中低植被覆盖不影响水体叶绿素质量浓度,植被覆盖能有效保持水体较高透明度,但不能降低水体COD质量浓度。在枯水期,高植被覆盖因为植物残体分解使氮素回流水体,导致水体含TN,NH4＋-N,NO3-_N质量浓度显著升高,中低植被覆盖植物残体分解同样显著增加水体氮素,但增加程度小于高植被覆盖;植物残体分解不影响水体TP质量浓度水平;高植被覆盖植物残体分解增加水体叶绿素质量浓度,中低植被覆盖则无影响;高中低植被覆盖区植物残体分解都显著增加水体混浊度,也提高了水体的BOD,对水体COD没有影响。     

太湖十八湾嗅味物质变化规律及除嗅方法

为了探索湖泊水体中嗅味物质的变化规律,解决湖泊水体的嗅味问题,本研究选取太湖十八湾围隔水域作为调查对象,从2009年12月到2010年8月,对嗅味物质土臭素(geosmin)和二甲基异茨醇(MIB)的含量进行分析检测,结果表明,geosmin的含量和MIB的含量在冬春季节较低,夏秋季节较高,随季节波动明显,MIB是主要的致嗅物质。为调控臭氧稳定性,降低臭氧衰减速率,室内实验采用硅藻土来吸附夹载臭氧,使臭氧分解速率常数由0.036/min降低到了0.015/min,由此制得了臭氧-硅藻土,并用该材料处理模拟嗅味物质水样。结果表明,10 min时,geosmin和MIB的去除率分别为73.4%和46.6%,高于对照中的45.9%和20.5%,30 min时,geosmin和MIB的去除率进一步提高到96.1%和79.7%,本研究结果为解决湖泊等天然水体的嗅味问题提供了新的思路。     

经济发展与环境退化的动态演进——环境库兹涅茨曲线研究进展

环境库兹涅茨曲线（EKC）阐述了经济发展和环境退化之间的动态演进过程，即随着经济的发展环境先不断恶化，到达顶点后逐渐改善。从实证研究、计量模型和分解分析三条线索回顾总结了国内外研究成果。随着EKC研究的发展，环境指标从污染指标扩展到资源生态指标和环境效率指标，而实证研究表明并非所有的环境指标和经济变量之间都存在“倒U型”关系。目前计量模型以简化式为多，结构式较少。由于分解分析方法能够定量化各种影响因素对污染排放变化的贡献率，因而在EKC成因研究中日益受到重视。尽管研究取得了较大进展，但生态环境阈值、污染的时空转移、数据处理与模型方法、环境控制政策和管理等方面仍需进一步研究，关键要在数据处理和模型构建方面取得突破。     

对总磷测定中样品消解加热时间的探讨

三组对照实验表明，地面水总磷的测定和消解时间可由30min缩减到15min.     

Quantification of the effects of management factors on maize (Zea mays L.) and cotton (Gossypium hirsutum L.) residues decomposition rate

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Thermal behaviors, combustion mechanisms, evolved gasses, and ash analysis of spent potlining for a hazardous waste management

An unavoidable but reusable waste so as to enhance a more circular waste utilization has been spent potlining (SPL) generated by the aluminum industry. The combustion mechanisms, evolved gasses, and ash properties of SPL were characterized dynamically in response to the elevated temperature and heating rates. Differential scanning calorimetric (DSC) results indicated an exothermic reaction behavior probably able to meet the energy needs of various industrial applications. The reaction mechanisms for the SPL combustion were best described using the 1.5-, 3- and 2.5-order reaction models. Fluoride volatilization rate of the flue gas was estimated at 2.24%. The SPL combustion emitted CO₂, HNCO, NO, and NO₂ but SO_x. The joint optimization of remaining mass, derivative thermogravimetry, and derivative DSC was achieved with the optimal temperature and heating rate combination of 783.5°C, and 5 °C/min, respectively. Interaction between temperature and heating rate exerted the strongest and weakest impact on DSC and remaining mass, respectively. The fluorine mainly as the formation of substantial NaF and CaF₂ in the residual ash. Besides, the composition and effect of environment of residual solid were evaluated. The ash slagging tendency and its mineral deposition mechanisms were elucidated in terms of turning SPL waste into a benign input to a circular waste utilization.