硫化氢制氢电解槽设计的改进及实验研究

硫化氢间接电解制氢过程中,在电解槽内采用湍流网结构可以有效地改善传质,基本消除扩散传质的影响。当槽压为1．1V,阴阳极流速皆为200L／h,电解温度为40℃的情况下,电解槽可以长时间保持良好性能,电流密度约为160mA／cm^2。     

考虑区域特点和车型差异的氢燃料电池汽车全生命周期减碳预测分析

发展氢燃料电池汽车是我国实现“双碳”战略的重要路径之一,目前我国多个区域正在推广应用包括乘用车、客车以及重卡在内的氢燃料电池汽车,如何量化研究未来不同车型和不同区域的氢燃料电池汽车减碳潜力成为如今的研究热点之一.基于全生命周期的评价方法,考虑了未来的汽车燃油经济性、电力碳排放因子、氢能碳排放因子和氢燃料电池汽车推广规模及制氢方式的区域差异,量化评价了不同类型的氢燃料电池汽车（FCV）、传统燃油汽车（ICEV）和纯电动汽车（BEV）的全生命周期碳排放量（以CO₂当量计）,对比分析了氢燃料电池汽车在不同时间及不同区域的减碳潜力,并对百公里氢耗量进行了不确定性分析.结果发现,到2025年氢燃料电池客车的全生命周期碳排放比传统燃油客车降低36.0%,而氢燃料电池重卡相较于传统燃油重卡并没有减碳效益.随着未来我国氢能来源结构的不断优化,到2035年氢燃料电池重卡的全生命周期碳排放比传统燃油重卡降低36.5%,相较于乘用车和客车两种车型,其减碳效益是最明显的.以2035年京津冀示范群为例,随着百公里氢耗量降低20%,FCV乘用车、客车和重卡的减碳规模分别增加了7.29%、9.93%和19.57%.因此建议氢燃料电池汽车推广应短期以客车为主,长期以重卡为主,乘用车推广作为补充.分区域和分阶段推广氢燃料电池汽车更有助于推进我国汽车领域的低碳化进程.     

用紫外辐射反演气溶胶单次散射反照率的方法研究

利用紫外辐射监测资料,结合对流层紫外与可见光辐射传输模式,反演气溶胶单次散射反照率(SSA).敏感性试验和误差分析表明:紫外辐照度对SSA敏感;气溶胶光学厚度(AOD)对反演SSA的误差影响最大,波长指数次之,地表反照率和其他因素的影响较小.使用该方法计算的珠三角地区的气溶胶单次散射反照率为0.84~0.99,平均值为0.92,与以往研究相比具有较好的一致性.     

土荆芥挥发油对豌豆根边缘细胞的诱导和胁迫作用

为探讨化感胁迫对根边缘细胞的诱导效应,实验采用悬空气培养法培养豌豆(Pisum sativum L.)露白种子,在保留根边缘细胞和去除根边缘细胞状态下,选取相对根长、根边缘细胞数量及死亡率、果胶甲基酯酶（PME）等指标研究了豌豆根边缘细胞对不同剂量土荆芥挥发油化感作用的响应。结果表明：1）与对照相比,随着挥发油处理剂量增加,根的伸长被显著抑制（P<0.05）。2）每个处理时间内,随着土荆芥挥发油剂量增加,根边缘细胞数量整体表现出先增加后减少的趋势,在低剂量2μL处理中达极大值。3）土荆芥挥发油诱导豌豆根边缘细胞死亡,随着处理时间的延长和处理剂量的增加,这种毒害效应程度加剧,除去边缘细胞实验组中10μL挥发油处理24 h时,根边缘细胞死亡率达到100%。在较低剂量挥发油作用下,保留根边缘细胞组的根边缘细胞死亡率高于去除根边缘细胞组,而在高剂量挥发油处理情况则相反。4）在同一处理时间,随挥发油剂量增加,各处理组PME活性持续升高,去处边缘细胞组处理24 h后不同剂量处理皆显著高于对照,而根边缘细胞数量总体表现先增加后减少。综合以上结果,保留根边缘细胞的根尖根边缘细胞的数量减少量较少,说明根边缘细胞能缓解土荆芥挥发油的化感胁迫;去除根边缘细胞组的PME活性升高较多,表明土荆芥化感胁迫诱导了根边缘细胞的产生。     

Alteration of photosystem II activity by atrazine on Chlamydomonas reinhardtii synchronized and asynchronized cell cycle cultures

Inhibition of photosystem II (PSII) activity by atrazine was investigated in the green alga Chlamydomonas reinhardtii during different states of the cell cycle. The algal cultures were maintained under continuous light or under light/dark cycle (16/8?h) to obtain homogenized cell cycle distribution. The cycle state of algal population was determined by the DNA content using flow cytometry and defined as newly divided cells before the initiation of DNA replication (G₀/G₁) and cells at the end of the replication cycle with fully duplicated DNA content (G₂/M). Under different synchronized states of the cell population, the photosynthetic activity was investigated after treatment at 10, 100, and 1000?µmol?L^?1 atrazine exposed for 24?h by using fluorescence parameters related to PSII activity measured with a plant efficiency analyzer and pulse-amplitude modulated methods. In this study, we found that the atrazine effect was different depending on cell cycle phases and the period of illumination. Algal cells under light–dark cycle showed inhibition of the PSII electron transport leading to an increase of heat energy dissipation by the PSII reaction center. Algal cells grown under continuous light was shown to be more resistant to atrazine than the cells grown under light–dark cycle.     

The Role of Organic Matter in Natural Aquatic Systems: Analytical Constraints

The dissolved organic matter in aquatic systems consists of a heterogeneous mixture of compounds with wide ranging chemical properties and diverse origins. the presence of organic matter (OM) in surface and ground waters has important implications with regard to the mobility and therefore fate of many potential organic and inorganic pollutants. the majority of the analytical approaches in current use require exhaustive pre-treatment steps which may lead to the formation of artefacts within the sample. an analytical technique based upon gel permeation chromatography is proposed as a more reliable procedure for the characterisation of naturally occurring dissolved organic matter.     

Mobilization of different metals between Tamarix parts and their crystal salts – soil system at the banks of river Nile,Aswan, Egypt

In order to study the relation of the mobility and distribution of metals between Tamarix parts and their crystal salts – soil system, different experiments were conducted with plant-rich and plant-free soils at the banks of river Nile, Aswan, Egypt. For these purposes, Tamarix top and subsoil samples near and far from the plant were collected from six different locations at the banks of river Nile. Elemental analysis of Fe, Mn, Ca, Mg, Cr, Cu, Ni, Zn, Cd and Pb in soil, and in different parts of Tamarix and their crystal salt samples was carried out by atomic absorption spectrometry, whereas Na and K were measured by atomic emission spectrophotometry. The bioavailability of metals in the soil samples was evaluated by determining their contents using sequential extraction single-step, providing higher metal concentrations in occluded Fe/Mn oxide fraction. The ratio of heavy metal concentrations in topsoil to that in subsoil enhancement (RTE) ranged from 0.67 to 4.4 and 0.22 to 4.61 for soil Tamarix and soil free from plant, respectively for all measured total element concentrations. Data indicate that the mobility expressed as transfer factor (TF) was obtained as Fe?>?Mg?>?Cr?>?Mn?>?Ca?>?K?>?Na, for Tamarix leaves. The major part of accumulated Na in Tamarix is retained in the plant leaves, while roots accumulated high concentration of Co.     

当归中4种金属微量元素的检测及其健康风险评价

为客观评价当归中金属微量元素对长期服用患者的健康影响,在当归的道地产区随机选取了9个采样点,采用高效毛细管电泳法同时检测当归中Mn、Fe、Mo、Cu四种金属微量元素含量,并对当归中的4种金属微量元素进行健康风险评价.结果表明,9个采样点中,有5个采样点当归的危害指数大于1,4种微量元素中Cu和Mo是影响人体健康的主要因素.     

A Pt-Bi bimetallic nanoparticle catalyst for direct electrooxidation of formic acid in fuel cells

Direct formic acid fuel cells are a promising portable power-generating device, and the development of efficient anodic catalysts is essential for such a fuel cell. In this work Pt-Bi nanoparticles supported on micro-fabricated gold wire array substrate were synthesized using an electrochemical deposition method for formic acid oxidation in fuel cells. The surface morphology and element components of the Pt-Bi/Au nanoparticles were characterized, and the catalytic activities of the three Pt-Bi/Au nanoparticle electrodes with different Pt/Bi ratios for formic acid oxidation were evaluated. It was found that Pt₄Bi₉₆/Au had a much higher catalytic activity than Pt₁₁Bi₈₉/Au and Pt₁₃Bi₈₇/Au, and Pt₄Bi₉₆/Au exhibited a current density of 2.7 mA·cm^-2, which was 27-times greater than that of Pt/Au. The electro-catalytic activity of the Pt-Bi/Au electrode for formic acid oxidation increased with the increasing Bi content, suggesting that it would be possible to achieve an efficient formic acid oxidation on the low Pt-loading. Therefore, the Pt-Bi/Au electrode offers a promising catalyst with a high activity for direct oxidation of formic acid in fuel cells.     

DOW CORNING 1-2577 Conformal Coating as an efficient diffusion material for cathode in the microbial fuel cell

In this study, DOW CORNING 1-2577 Conformal Coating was proposed for the cathode diffusion layer of the microbial fuel cell (MFC). In MFCs, stainless steel mesh cathodes using DOW CORNING 1-2577 Conformal Coating/carbon as the diffusion layer and two poly (dimethylsiloxane) (PDMS)/carbon diffusion layers and carbon cloth cathode with four poly (tetrafluoroethylene) (PTFE) diffusion layers were constructed for comparison. Under the same operational condition, the MFCs with the DOW CORNING 1-2577 Conformal Coating/carbon diffusion layer produced the maximum power density of 1585±52 mW·m^-2, compared with those using poly (tetrafluoroethylene) (PTFE) diffusion layers (1421±45 mW·m^-2) and poly (dimethylsiloxane) (PDMS)/carbon diffusion layers (1353±49 mW·m^-2). The DOW CORNING 1-2577 Conformal Coating could be an alternative for the diffusion layer construction in the MFC due to its remarkable performance and much simple construction procedure.