活性磷酸盐用标准色列快速测定

利用钒磷酸盐相对稳定的特点,采用一种快速测定活性磷酸盐的方法,标准色列稳定时间选定为5天,测定范围为0 5～5 0mg L,该方法具有标准制作简便,测定快速的特点,特别适合于工程调试现场监测。     

兰州市两场典型降水事件稳定同位素特征及其水汽来源

为了加深对短时间尺度下降水同位素变化规律的认识,利用兰州市2019年夏季典型的长历时弱降水(6月26～27日)和短时强降水(7月28日)事件短时间尺度(10 min和30 min)的连续样品,结合HYSPLIT模型对降水氢氧稳定同位素的变化特征及其机制进行分析.结果表明,降水初始阶段,二次蒸发效应使事件内连续降水的大气水线(SMWL)斜率偏小.连续样点大都分布在GMWL和LMWL上方,且SMWL的截距都大于局地年平均过量氘(8.13),说明降水一定程度上经历了水汽再循环. 6月26～27日连续2 d的降水事件,第1 d的δ¹⁸O呈"L"型变化,第2 d呈波动变化,δ¹⁸O不遵循降雨量效应. 7月28日,δ¹⁸O呈平稳下降趋势,变化范围超过9‰. 6月26日, 500 m高度层水汽输送路径整体较短, 27日以局地水汽蒸发为主. 7月28日降水的水汽来源变化不明显,气团较单一,同位素值无明显波动.因此,对于短时间尺度下的单次降水事件,水汽来源的异同也是降水期间同位素变化的原因之一.     

悬浮液直接进样塞曼石墨炉平台原子吸收法测定土壤中痕量铅

研究了悬浮液直接进样 ,石墨炉平台原子吸收法测定土壤中痕量铅 ,方法简便快速 ,检出限 (3σ)为 4.4× 1 0 - 1 2 g,相对标准偏差 (n=6)小于 3 .0 % ,回收率在 91 %～ 1 0 7%之间     

Crash and injury prevention estimates for intersection driver assistance systems in left turn across path/opposite direction crashes in the United States

Abstract

Objective: The objective of this research study was to estimate the number of left turn across path/opposite direction (LTAP/OD) crashes and injuries that could be prevented in the United States if vehicles were equipped with an intersection advanced driver assistance system (I-ADAS).

Methods: This study reconstructed 501 vehicle-to-vehicle LTAP/OD crashes in the United States that were investigated in the NHTSA National Motor Vehicle Crash Causation Survey (NMVCCS). The performance of 30 different I-ADAS system variations was evaluated for each crash. These variations were the combinations of 5 time-to-collision (TTC) activation thresholds, 3 latency times, and 2 different response types (automated braking and driver warning). In addition, 2 sightline assumptions were modeled for each crash: One where the turning vehicle was visible long before the intersection and one where the turning vehicle was only visible within the intersection. For resimulated crashes that were not avoided by I-ADAS, a new crash delta-V was computed for each vehicle. The probability of Abbreviated Injury Scale 2 or higher injury in any body region (Maximum Abbreviated Injury Scale [MAIS] 2+F) to each front-row occupant was computed.

Results: Depending on the system design, sightline assumption, I-ADAS variation, and fleet penetration, an I-ADAS system that automatically applies emergency braking could avoid 18–84% of all LTAP/OD crashes. Only 0–32% of all LTAP/OD crashes could have been avoided using an I-ADAS system that only warns the driver. An I-ADAS system that applies emergency braking could prevent 47–93% of front-row occupants from receiving MAIS 2?+?F injuries. A system that warns the driver in LTAP/OD crashes was able to prevent 0–37% of front-row occupants from receiving MAIS 2?+?F injuries. The effectiveness of I-ADAS in reducing crashes and number of injured persons was higher when both vehicles were equipped with I-ADAS.

Conclusions: This study presents the simulated effectiveness of a hypothetical intersection active safety system on real crashes that occurred in the United States. This work shows that there is a strong potential to reduce crashes and injuries in the United States.     

Biofluorescence as a survey tool for cryptic marine species

As ecosystems come under increasing anthropogenic pressure, rare species face the highest risk of extinction. Paradoxically, data necessary to evaluate the conservation status of rare species are often lacking because of the challenges of detecting species with low abundance. One group of fishes subject to this undersampling bias are those with cryptic body patterns. Twenty‐one percent of cryptic fish species assessed for their extinction risk (International Union for Conservation of Nature [IUCN]) are data deficient. We developed a nondestructive method for surveying cryptically patterned marine fishes based on the presence of biofluorescence (underwater biofluorescence census, UBC). Blue LED torches were used to investigate how widespread biofluorescence was in cryptic reef fishes in the Coral Triangle region. The effectiveness of UBC to generate abundance data was tested on a data‐deficient pygmy seahorse species (Hippocampus bargibanti) and compared with data obtained from standard underwater visual census (UVC) surveys. We recorded 95 reef fish species displaying biofluorescence, 73 of which had not been previously described as biofluorescent. Of those fish with cryptic patterns, 87% were biofluorescent compared with 9% for noncryptic fishes. The probability of species displaying biofluorescence was 70.9 times greater for cryptic species than for noncryptic species. Almost twice the number of H. bargibanti was counted using the UBC compared with UVC. For 2 triplefin species (Ucla xenogrammus, Enneapterygius tutuilae), the abundance detected with UBC was triple that detected with UVC. The UBC method was effective at finding cryptic species that would otherwise be difficult to detect and thus will reduce interobserver variability inherent to UVC surveys. Biofluorescence is ubiquitous in cryptic fishes, making this method applicable across a wide range of species. Data collected using UBC could be used with multiple IUCN criteria to assess the extinction risk of cryptic species. Adopting this technique will enhance researchers’ ability to survey cryptic species and facilitate management and conservation of cryptic marine species.     

生物炭施用5 a后对桂北桉树人工林土壤有机碳组分的影响

研究生物炭不同施用量施用5 a后桉树人工林土壤有机碳组分的变化特征，明确生物炭施用下土壤的固碳潜力，为桉树林业废弃物生物炭的土壤改良效应提供科学依据.基于2017年建立的桉树人工林生物炭中长期定位试验，以桉树人工林废弃枝条为原料，在500℃条件下厌氧制备生物炭，选取CK （0%）、T1（0.5%）、T2（1.0%）、T3（2%）、T4（4%）和T5（6%）这6个处理，一次性施用生物炭5 a后测定不同处理下有机碳组分含量特征.结果表明：①与对照相比，土壤有机碳及其组分随生物炭施用量的增加而增大，且在T4或T5达到最大值，土壤有机碳、可溶性有机碳、易氧化态有机碳、颗粒有机碳、微生物生物量碳和碳储量分别增加了101.62%、67.46%、143.03%、164.78%、110.88%和41.73%.②随着生物炭施用量的增加，各生物炭处理土壤轻组有机碳和重组有机碳含量在0~10、10~20、20~30 cm土层的增幅分别为41.41%~140.63%、9.26%~87.04%、-19.54%~106.90%和15.32%~78.99%、15.72%~75.25%、89.49%~148.64%.0~30 cm土层土壤轻组有机碳和重组有机碳含量的平均值亦呈现增大的趋势，土壤碳库中以较稳定的重组有机碳为主.③土壤有机碳、碳储量和有机碳组分含量均随着土层的加深而减小.总体上，生物炭施用5 a显著增加了土壤有机碳和碳组分含量，有利于提高土壤固碳能力和土壤稳定性碳库，生物炭施用是提升桉树林土壤质量的有效措施.研究结果可为林业废弃物资源化利用和桉树人工林土壤肥力提升提供参考依据.     

Effects of anthropogenic disturbance on primate density at the landscape scale

Accurate estimations of the abundance of threatened animal populations are required for assessment of species’ status and vulnerability and conservation planning. However, density estimation is usually difficult and resource demanding, so researchers often collect data at local scales. However, anthropogenic pressures most often have landscape-level effects, for example, through habitat loss and fragmentation. We applied hierarchical distance sampling (HDS) to transect count data to determine the effect of habitat and anthropogenic factors on the density of 3 arboreal primate species inhabiting 5 distinct tropical forests across a landscape of 19,000 km² in the Udzungwa Mountains of Tanzania. We developed a novel, multiregion extension of HDS that allowed us to model density and detectability jointly across forests without losing site-specific information. For all species, the effect of anthropogenic disturbance on density was overwhelmingly negative among metapopulations: −0.63 Angolan colobus (Colobus angolensis palliatus) (95% Bayesian CI −1.03 to −0.27), −0.54 Udzungwa red colobus (Procolobus gordonorum) (−0.89 to −0.22), and −0.33 Sykes' monkey (Cercopithecus mitis monoides) (−0.63 to −0.07). Some responses to habitat factors were shared, notably the negative effect of elevation and the positive effect of climber coverage. These results are important for conservation science and practice because: the among-populations negative responses to anthropogenic disturbance provides a foundation for development of conservation plans that hold at the landscape scale, which is a comprehensive and cost-efficient approach; the among-species consistency in responses suggests conservation measures may be generalized at the guild level, which is especially relevant given the functional importance of primates in tropical rainforests; and the greater primate densities in areas at low elevation, which are closer to human settlements, point to specific management recommendations, such as the creation of buffer zones and prioritization of areas for protection.     

大都市群的环境问题及其环境保护战略

从实现新时期统筹发展的国家战略需求出发,剖析了大都市群跨区域交叉污染、复合污染、累计污染的特点,指出这些区域已成为环境资源“漏斗区”和突发性环境危机的风险区。认为只有采取主动引导发展的国家环境战略才能有效地解决大都市群和环境的协调可持续发展问题。阐述了主动环保战略的重大措施包括引导调整发展布局、转变经济增长方式、转变生活方式、创新国家环境管理体制、创新环境科技体系和系统、人工提高环境承载能力等。     

Little effect of excessive biofouling on the uptake of organic contaminants by semipermeable membrane devices

The effects of water flow rate and antifouling agents on the extent of biofouling and on the uptake of non-polar organic contaminants by semipermeable membrane devices (SPMDs) were studied during four field experiments in the Western Wadden Sea. Biofouling densities on the sampler surface ranged from 0.3 to 16 g dry weight dm⁻². Water sampling rates were estimated from the dissipation rates of performance reference compounds (PRCs). The antifouling agents Irgarol and capsaicin (33 mg per ml triolein) had no noticeable effect on the extent of fouling, and caused only a 5–10% increase in the absorbed amounts. Enhanced flow rates had only a minimal effect on the amount of biofouling, but caused the water sampling rates to increase by a factor of 1.2–2. Increases in PRC-derived sampling rates were reflected by increases in the absorbed amounts for compounds that were in the linear uptake stage of the sampling process. The results imply (1) that extreme biofouling does not always result in reduced sampling rates, (2) that extreme biofouling does not preclude the existence of flow effects on the sampling rates, and (3) that differences in uptake rates are quantitatively reflected by the dissipation rates of PRCs.     

SBR法降解处理日化厂废水的实验研究

日化厂废水成分复杂,其中表面活性剂、含P化合物、油脂、色素等严重污染生态环镜,较难处理.本文采用小规模的间歇式活性污泥法(SBR)生物反应器降解处理日化厂废水,分析了废水降解过程中污泥体积指数、污泥负荷、容积负荷等微生物学的特性变化,并讨论了曝气时间、污泥负荷、容积负荷对污染物去除率的影响.结果表明,通过对普通活性污泥的培养与驯化,利用SBR工艺降解处理日化厂废水是可行的.当曝气时间为4.5 h,污泥负荷为1.2 kg/(kg·d)(以MLSS计的COD),容积负荷为2.1～2.3g/(L·d)时,COD、油脂、总磷、表面活性剂(SAA)、SO42-等的去除率分别可达92.3%,99.1%,99.3%,99.3%,99.0%和98.9%.