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991.
首先正确估计样品BOD5浓度范围,并测定稀释水的溶解氧,然后根据稀释倍数公式计算3个适当的稀释倍数.与其它方法相比,本方法省时、可靠,适用性强,能够确保BOD5样品分析一次成功.在BOD5样品分析中具有广泛的应用价值. 相似文献
992.
The growth and alkaline phosphatase activity (APA) of two raphidophyceae species Chattonella marina and Heterosigma akashiwo were investigated in response to P-limitation and subsequent addition of dissolved inorganic phosphorus (DIP, NaH2PO4) and two dissolved organic phosphorus (DOP) compounds: guanosine 5-monophosphate (GMP) and triethyl phosphate (TEP). APAlevels increased greatly after P-starvation as the decrease of the cellular phosphorus quotes (Qp). C. marina responded to P-limitation quickly and strongly, with 10-fold increase in APA within 24 hr after P-starvation. The larger difference between maximal and minimal Qp values in C. marina indicated its high capacity in P storage. APA of H. akashiwo wasmaximally enlarged about 2.5 times at 48 hr of P-starvation. After the addition of nutrients, cell numbers of C. marina increased in all treatments including the P-free culture, demonstrating the higher endurance of C. marina to P-limitation. However, those of H. akashiwo increased only in DIP and GMP cultures. APA increased only after the addition of the monophosphate ester GMP. The results suggest that quick responses of C. marina to P-limitation, high capacity in P storage as well as endurance for P-depletion provide this species an ecological advantage in phytoplankton community competition under DIP-limited conditions. 相似文献
993.
Carbonyl compounds are important intermediates in atmospheric photochemistry, but their primary sources are still not understood well. In this work, carbonyls, hydrocarbons, and alkyl nitrates were continuously measured during November 2011 at a rural site in the Yangtze River Delta region of China. Mixing ratios of carbonyls and hydrocarbons showed large fluctuations during the entire measurement. The average level for total measured volatile organic compounds during the pollution episode from 25th to 27th November, 2011 was 91.6 ppb, about 7 times the value for the clean period of 7th-8th, November, 2011. To preliminarily identify toluene sources at this site, the emission ratio of toluene to benzene (T/B) during the pollution episode was determined based on photochemical ages derived from the relationship of alkyl nitrates to their parent alkanes. The calculated T/B was 5.8 ppb/ppb, significantly higher than the values of 0.2-1.7 ppb/ppb for vehicular exhaust and other combustion sources, indicating the dominant influence of industrial emissions on ambient toluene. The contributions of industrial sources to ambient carbonyls were then calculated using a multiple linear regression fit model that used toluene and alkyl nitrates as respective tracers for industrial emission and secondary production. During the pollution episode, 18.5%, 69.0%, and 52.9% of measured formaldehyde, acetaldehyde, and acetone were considered to be attributable to industrial emissions. The emission ratios relative to toluene for formaldehyde, acetaldehyde, and acetone were determined to be 0.10, 0.20 and 0.40 ppb/ppb, respectively. More research on industrial carbonyl emission characteristics is needed to understand carbonyl sources better. 相似文献
994.
The pollution status and characteristics of PAEs (phthalate esters) were investigated in indoor air of offices, and PAEs of both gas-phase and particulate-phase were detected in all the samples. The concentration (sum of the gas phase and the particulate phase) was 4748.24 ng/m3, ranging between 3070.09 and 6700.14 ng/m3. Diethyl phthalate, dibutyl phthalate, and di(2-ethylhexyl) phthalate were the most abundant compounds, together accounting for 70% of the Σ6PAEs. Dividing the particulate-phase PAEs into four size ranges (<2.5, 2.5-5, 5-10, >10 μm), the result indicated that PAEs in PM2.5 were the most abundant, with the proportion of 72.64%. In addition, the PAE concentration in PM2.5 correlated significantly with the total particulate-phase PAEs (R2 = 0.85). Thus, the amount of PAEs in PM2.5 can be estimated from the total amount of particulate-phase PAEs using this proportion. In a comparison between the offices and a newly decorated study room, it was found that pollution characteristics were similar between these two places. Thus, it is implied that the PAE concentration decreased by 50% 2 yr after decorating. 相似文献
995.
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997.
本文从实际出发对市辖区餐饮业这个突出的环境敏感问题,查摆了现象,分析了产生原因,结合现阶段市辖区餐饮业环境管理实际,提出了针对性整改的措施。 相似文献
998.
我省环境监测的远程数据传输也应用多年,但目前普遍存在着设备老化、传输手段落后、设备运行不稳定等状况,急需对现有系统进行换代或改造。通过对目前常用的数据传输方式的比较分析,采用GPRS传输方案实现我省环境监测数据远程传输系统是最优的,是斜学的、可行的。 相似文献
999.
她注定是一名行者。她用镜头和笔记录下了视野中的中国生态环境,她倾听大自然的每一次呼吸,她体味着那些被生态所累的无奈:风沙喧嚣,乌啼虫鸣,江河呜咽,地球变迁……她叫汪永晨,绿家园志愿者的召集人——她用专业化的目光,审视着自然与生态最细微的变化。她在记录中行走,她在行走中记录。某种意义上说,通过她的眼睛,我们看到了一部生动的环境史。
本期,汪永晨为读者提供的是阿尔金山的一组图片与文字。让我们一起走进汪永晨,一起聆听她讲的生态环境与家园的故事。[编者按] 相似文献
1000.
《中共广东省委关于制定全省国民经济和社会发展第十一个五年规划的建议》指出,要坚持继承、创新、提高、发展,科学总结过去、谋划未来。其中,有关可持续发展和建设资源节约型和环境友好型社会等内容将开启和谐社会之门。
《建议》在正式向社会公布后,立即引起社会各界的广泛关注。未来广东,如何谋求经济发展模式之变?如何应对城镇化进程加快带来的环境压力?
本期特推出“广东‘十一五’:奏响可持续发展强音”嘉宾访谈。[编者按] 相似文献