加拿大的职业教育与CBE教学模式

介绍了职业教育的基本概况和社区学院教育的主要特点,分析了CBE教学模式的形成背景、组成与结构、实施步骤、课程开发流程以及基本特征,最后指出了CBE教学模式的若干缺陷．     

应用短乳杆菌去除养殖水体中亚硝酸盐

对短乳杆菌(Lactobacillus brevis)在养殖水体中去除亚硝酸盐的能力以及主要影响因素的试验结果表明,短乳杆菌能够在复杂的养殖水环境中有效去除亚硝酸盐.短乳杆菌对养殖水体中亚硝酸盐去除的适宜条件为:水温25 ℃以上,pH≤8.0,菌液使用量≤10 mg·L-1,亚硝酸盐本底质量浓度≤1.0 mg·L-1,有效处理时间为0～48 h.除了活菌体,短乳杆菌的代谢产物也有去除亚硝酸盐的能力.研究表明,短乳杆菌可作为一种潜在的养殖水体环境生物修复产品而加以开发利用.     

锰砂催化电化学方法对染料K2G脱色效果的研究

研究了锰砂催化电化学方法对偶氮染料K2G的脱色效果 .结果表明 ,锰砂中的主要成份MnOOH对电化学过程具有催化作用 ,可有效地提高染料的脱色效率 .对锰砂的X光衍射实验证明 ,反应过程中MnOOH的含量无较大变化 .染料溶液的起始pH值对其脱色率没有明显的影响 .在最佳电流密度di 为 0 2 6A·dm- 2 ,Na2 SO4 浓度为0 0 1mol·l- 1时 ,电解 70min ,浓度为 1 0 0mg·l- 1的染料K2G的脱色率能达到 99% .     

富营养化水体中微囊藻细胞碎屑对氨氮的吸附特性

以微囊藻细胞碎屑作为水体有机质颗粒悬浮物的代表,模拟研究了有机质颗粒悬浮物对无机氮的吸附行为及吸附特性.实验表明,细胞碎屑颗粒对氨氮的吸附在30min内即可接近吸附平衡,吸附符合Henry吸附模式,在吸附剂浓度为10mg·l-1,氨氮初始浓度为1.0mg·l-1,pH7.0的实验条件下,吸附分配系数高达30426L·kg-1.碎屑浓度、pH值和盐度对吸附具有一定的影响.     

南岳自然保护区人文资源的调查研究

南岳自然保护区素为天下名山,层峦叠翠,风光旖旎,灵动俊秀的自然景观,源远流长的宗教文化,古朴神奇的历史遗迹,形成了博大精深的旅游资源.我国加入WTO后,随着世界旅游业的蓬勃发展,一个全新的旅游分支文化旅游正呈现出迅猛的发展势头.南岳作为素有文明奥区之称,进行文化资源的调查,构筑系统的旅游文化体系,开拓旅游市场,提升旅游品位,做好保护与利用旅游资源这篇文章有着重要意义.     

Use of subsampled traffic data to estimate roadway emissions, including conversion to MOBILE6 vehicle classifications

Air quality is degraded by many factors, among which the emissions from on-road vehicles play a significant role. Timely and accurate estimate of such emissions becomes very important for policy-making and effective control measures. However, lack of traffic data and outdated emission software make this task difficult. This research has demonstrated a new method that facilitates the vehicular emission inventories at the local level by using shorter-time Highway Performance Monitoring System (HPMS) traffic data along with the latest U.S. Environment Protection Agency (EPA) emission modeling software, MOBILE6. The conversion methodology was developed for converting readily available HPMS traffic volume data into EPA MOBILE-based traffic classifications, and a corresponding software program was written for automating the process. EPA MOBILE6 model was used to obtain emissions of nitrogen oxides (NOx), volatile organic compound (VOC), and cabon monoxide (CO) emitted by the parent traffic and subsampled traffic data, and these emissions were additionally compared. The case study has shown that the difference of the magnitude between the emission estimates produced by certain subsampled and parent traffic data are minor, indicating that subsampled HPMS data can be used for reporting parent traffic emissions. It was also observed that traffic emissions follow a Weibull distribution, and NOx emissions were more sensitive to the traffic data composition than VOC and CO. Lastly, use of average emission values of 20 or 30 consecutive minutes appears to be valid for representing hourly emissions.     

Distribution of organochlorine pesticides in seawater of the Bering and Chukchi Sea.

Organochlorine pesticides (OCPs) in the seawater collected in the Bering and Chukchi Seas during the First Chinese Arctic Research Expedition were confirmed by gas chromatography-mass spectrometry (GC-MS) and analyzed by capillary gas chromatography with micro-electron capture detector (GC-microECD). The average of hexachlorocyclohexanes (HCHs; sum of isomers alpha-, beta-, gamma-, delta-) was nearly equal in the Bering Sea (mean concentration 412.7 pg/l) and in the Chukchi Sea (mean concentration 445.8 pg/l), which showed no obvious latitudinal difference of these two regions. Compared with previously reported studies, concentrations of OCPs in these regions were much lower than the levels in the last decades. The ratio of alpha:gamma HCH was 5.0 and 3.4 for the Bering and Chukchi sea, respectively, which indicated the different pesticide composition in these two regions. Many other OCPs with different residue patterns were also found for the first time in the investigation regions. Heptachlor epoxide (in the Bering Sea) and heptachlor (in the Chukchi Sea) were main OCPs contaminants besides HCHs.     

甘蔗糖蜜酒精废液色素特性及脱除的研究

定性地分析了甘蔗糖蜜酒精废液色素的主要成分，并对其颜色特征及稳定性进行了深入的研究，通过对离子交换树脂，吸附树脂和活性炭等的脱色试验比较，筛选出较理想的脱色剂－－粉状活性炭，并得出了相应的脱色工艺参数，脱色率达１００％。     

Trace analysis of dissolved polychlorinated organic compounds in the water of the Yangtse River (Nanjing, China)

Eighteen organochlorine contaminants from the water samples of the Yangtse River have been qualitatively and quantitatively analyzed. The analysis of polychlorinated organic compounds (PCOCs) extracted by C18 Solid Phase Extract (SPE) was performed using HP6890 gas chromatograph coupled by ECD detector. The analytical results demonstrate that the analytical methods are reliable based on the fact that most of the recoveries for the targeted compounds are 60-90%. Most of the concerned contaminants, i.e. chlorinated pesticides and PCBs were found in the water samples of the Yangtse River, but their concentration was very low, <2.97 ng l(-1), which is far less than 1 microg l(-1)--the standard of drinking water of China. It is apparent that the PCOCs were in high concentration during the dry season, and in low concentration during the rainy season. The situation of PCOCs contamination in the water of the Yangtse River in 1999 was greatly improved in comparison with 10 years ago.     

磷酸铵镁沉淀法脱氨机理、应用及沉淀剂循环

铵根离子可以和镁盐、磷酸根在适当的条件下生成磷酸铵镁沉淀，利用这一反应可以去除水中的氨氮。本文从磷酸铵镁的性质、反应机理、反应条件及沉淀剂循环利用等方面，对这一方法进行了介绍和总结，并对今后该技术发展提出了建议。