反距离加权法天气衍生品空间基差风险对冲效果

天气衍生品作为一项金融创新产品,为天气风险的管理和转移提供了新的途径.与传统衍生品不同的是,天气衍生品合约标的物是常见的天气变量,本身不具有资产价格,因此面临的并不是传统意义上的基差风险.天气衍生品的基差风险包括产品基差风险和空间基差风险,这些基差风险严重影响着天气衍生品的风险对冲效果,阻碍了市场发展,也是研究的重点与难点.相比产品基差风险因特定部门而异,空间基差风险具有不可避免的特点.依据反距离加权法,增加空间多样性构建天气衍生品组合,可用于对冲空间基差风险,但需要经验数据验证.研究表明,天气衍生品收益与假设收益的均方根误差(RMSE)能够很好的量化天气敏感企业遇到的天气风险,天气风险对冲效果可以通过RMSE的变化值进行度量;构建中国华东地区降雨量看跌期权交易,相较单一地区收益偏差,期权买方采用空间组合策略取得了更好的空间基差风险对冲效果.此外,研究结果发现,在构建天气衍生品空间组合时,组合中气象观测点的数目并不是越多越好,即较少的观测点个数即能显著降低天气风险对冲效果,这也为实践操作提供了便利.     

废催化裂化催化剂的危险性及污染特征

为考察我国废催化裂化(FCC)催化剂的危险性及污染特征,以国内典型FCC装置的废催化剂为研究对象,分析其易燃性、反应性、腐蚀性、浸出毒性、毒性物质含量及急性毒性。研究发现:废FCC催化剂无易燃性、反应性、腐蚀性、急性毒性危险;未检测出具有致癌致突变性的有机污染物;废FCC催化剂的特征污染物为Ni及其化合物,Ni的浸出浓度低于国家标准限值,Ni的存在形态为Ni Al2O4尖晶石,而非具有致癌性的Ni O形态。     

催化分解N_2O催化剂的研究新进展

直接催化分解N2O技术已成为当前国内外工业脱除N2O应用研究的主流和发展方向,催化剂是技术核心。综述了贵金属、金属氧化物、沸石以及其他用于分解N2O的新型固体催化剂的最新研究现状。对催化剂的研究方法、思路进行了评述,总结了现存的问题,并展望了直接催化分解N2O催化剂未来的发展方向。其中,沸石类催化剂由于高活性和结构稳定性,有望成为理想的商用催化剂。     

一种复合催化剂及其光催化降解煤矿瓦斯的性能研究

为提高催化剂光催化降解煤矿瓦斯效率,运用溶胶-凝胶浸渍过程将具有优异吸附性能的活性炭颗粒引入催化剂,制备了新型复合催化剂Ga2O3/AC。采用XRD、SEM、N2吸附等方法对新型复合催化剂的结构形貌及比表面积进行理化表征,验证了复合催化剂制备方法的可行性。同时以真空紫外灯为光源,进行光催化氧化降解瓦斯的模拟实验,对比考察Ga2O3、活性炭颗粒及复合催化剂的光催化活性。结果表明,相比单一Ga2O3,复合催化剂光照时间为180 min后对甲烷的降解率提高了13%,达到100%去除率。     

加拿大发布6项偶氮金属筛查评估

正2014年5月20日来源:Chemical Watch网站加拿大规制部门开始就它们认定6种偶氮金属配合物和物质不构成《加拿大环境保护法》(CEPA)定义的环境或健康威胁的决定征求公众评议。针对偶氮基团的快速筛查评估是加拿大对其《国内物质清单》上的优先性物质进行评估的工作的一部分。在确定这些配合物和物质不满足将要求进行进一步研究或更严格规制的任何标准前,环境和卫生主管部门已经发现,所有6种偶氮物质的国内生产量均不足以触发进一步评估。只有一种基于C10-14烷基胺的     

A potentiometric cobalt-based phosphate sensor based on screen-printing technology

A potentiometric cobalt-based screen-pritning sensor was fabricated by electroplating cobalt on the surface of a screen-printing electrode as the sensitive layer for the determination of dihydrogenphosphate （H2PO4） in wastewater samples. The electrochemical performance of this sensor was fully examined to determine its detection calibration, detection limit, response time, selectivity, and interference with pH, various ions, and dissolved oxygen （DO）. The cobalt-based phosphate sensor showed a phosphate-selective potential response in the range of 10 5mol·L^-1 to 10^-1 mol^-1, yielding a detection limit of 3.16 × 10μmol·L^l and a slope of -37.51 mV·decade＇ in an acidic solution （pH 4.0） of H2PO4-. DO and pH were found to interfere with sensor responses to phosphate. Ultimately, the performance of the sensor was validated for detecting wastewater samples from the Xiaojiahe Waste- water Treatment Plant against the standard speetrophotometric methods for HzPO4 analysis. The discrepancy between the two methods was generally ＋5% （relative standard deviation）. Aside from its high selectivity, sensitivity, and stability, which are comparable with conventional bulk Co-wire sensors, the proposed phosphate sensor presents many other advantages, such as low price, compactness, ease of use, and the possibility of integration with other analytical devices, such as flow injectors.     

Novel synthetic approaches and TWC catalytic performance of flower-like Pt/CeO2

A novel Ultrasonic Assisted Membrane Reduction （UAMR）-hydrothermal method was used to prepare flower-like Pt/CeO2 catalysts. The texture, physical/chemical properties, and reducibility of the flower-like Pt/CeO2 catalysts were characterized by X-Ray Diffraction （XRD）, Scanning Electron Microscope （SEM）, Transmission Electron Microscope （TEM）, N2 adsorption, and hydrogen temperature programmed reduction （HE-TPR） techniques. The catalytic performance of the catalysts for treating automobile emission was studied relative to samples prepared by the conventional wetness impregnation method. The Pt/CeO2 catalysts fabricated by this novel method showed high specific surface area and metal dispersion, excellent three-way catalytic activity, and good thermal stability. The strong interaction between the Pt nanoparticles and CeO2 improved the thermal stability. The Ce4＋ ions were incorporated into the surfactant chains and the Pt nanoparticles were stabilized through an exchange reaction of the surface hydroxyl groups. The SEM results demonstrated that the Pt/CeO2 catalysts had a typical three-dimensional （3D） hierarchical porous struc- ture, which was favorable for surface reaction and enhanced the exposure degree of the Pt nanoparticles. In brief, the flower-like Pt/CeO2 catalysts prepared by UAMR-hydrothermal method exhibited a higher Pt metal dispersion, smaller particle size, better three-way catalytic activity, and improved thermal stability versus conven- tional materials.     

Effects of bicarbonate and cathode potential on hydrogen production in a biocathode electrolysis cell

A biocathode with microbial catalyst in place of a noble metal was successfully developed for hydrogen evolution in a microbial electrolysis cell （MEC）. The strategy for fast biocathode cultivation was demonstrated. An exoelectrogenic reaction was initially extended with an H2-full atmosphere to enrich Ha-utilizing bacteria in a MEC bioanode. This bioanode was then inversely polarized with an applied voltage in a half-cell to enrich the hydrogen-evolving biocathode. The electrocatalytic hydrogen evolution reaction （HER） kinetics of the biocathode MEC could be enhanced by increasing the bicarbonate buffer concentration from 0.05 mol·L-1 to 0.5 mol· L-1 and/or by decreasing the cathode potential from -0.9 V to - 1.3 V vs. a saturated calomel electrode （SCE）. Within the tested potential region in this study, the HER rate of the biocathode MEC was primarily influenced by the microbial catalytic capability. In addition, increasing bicarbonate concentration enhances the electric migration rate of proton carriers. As a consequence, more mass H＋ can be released to accelerate the biocathode-catalyzed HER rate. A hydrogen production rate of 8.44 m3. m 3. d1 with a current density of 951.6 A. m-3 was obtained using the biocathode MEC under a cathode potential of - 1.3 V vs. SCE and 0.4 mol· L-1 bicarbonate. This study provided information on the optimization of hydrogen production in biocathode MEC and expanded the practical applications thereof.     

Using crosslinked polyvinyl alcohol polymer membrane as a separator in the microbial fuel cell

Separator between anode and cathode is an essential part of the microbial fuel cell （MFC） and its property could significantly influence the system perfor- mance. In this study we used polyvinyl alcohol （PVA） polymer membrane crosslinked with sulfosuccinic acid （SSA） as a new separator for the MFC. The highest power density of 7594-4 mW-m-2 was obtained when MFC using the PVA membrane crosslinked with 15% of SSA due to its desirable proton conductivity （5.16 x 10-2 S.cml）. The power density significantly increased to 11064- 30 mW.m-2 with a separator-electrode-assembly config- uration, which was comparable with glass fiber （11704- 46 mW.m-2）. The coulombic efficiencies of the MFCs with crosslinked PVA membranes ranged from 36.3% to 45.7% at a fix external resistance of lO00f2. The crosslinked PVA membrane could be a promising alter- native to separator materials for constructing practical MFC system.     

气相色谱-串联质谱法测定塑料食品接触材料中DBP及DEHP迁移量

建立了气相色谱串联质谱法(GC-MS/MS)测定食品接触材料中邻苯二甲酸二丁酯(DBP)及邻苯二甲酸二(2-乙基己基)酯(DEHP)向食品模拟物中迁移量的方法.按一定条件浸泡后,脂性模拟物异辛烷直接进样分析,而水性模拟物(水、3%乙酸溶液及10%乙醇溶液)用正己烷进行液液萃取后进样分析.结果表明,DBP标准溶液在0.02—1.00 mg.L-1范围内线性良好,而DEHP标准溶液在0.04—1.00 mg.L-1范围内线性良好;本方法在4种模拟物浸泡液中,回收率为80.3%—103.4%,相对标准偏差(n=6)为1.37%—5.71%.该方法灵敏度高、定量准确、抗干扰能力强、重现性好,可用于食品接触材料中DBP及DEHP向食品模拟物中的迁移量测定.