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241.
The overall regional development planning pattern has been considered to be a new and effective pattern as for development of provincial economy. The article analyzed the current conditions of the west of Shandong Province and tried to find the generation mechanisms of current non-balanced economic devel- opment of Shandong Province. And then approaches to regional development were put forward according to the theory of regional development pattern as a whole.  相似文献   
242.
In China, vegetable croplands are characterized by intensive fertilization and cultivation, which produce significant nitrogenous gases to the atmosphere. In this study, nitric oxides (NOX) and nitrous oxide (N2O) emissions from the croplands cultivated with three typical vegetables had been measured in Yangtze River Delta of China from September 2 to December 16, 2006. The NO fluxes varied in the ranges of 1.6–182.4, 1.4–2901 and 0.5–487 ng Nm?2 s?1 with averages of 33.8 ± 44.2, 360 ± 590 and 76 ± 112 (mean ± SD) ngNm?2 s?1 for cabbage, garlic, and radish fields (n = 88), respectively. N2O fluxes from the three vegetable fields were found to occur in pulses and significantly promoted by tillage with average values of 5.8, 8.8, and 4.3 ng Nm?2 h?1 for cabbage, garlic, and radish crops, respectively. Influence of vegetables canopy on the NO emission was investigated and quantified. It was found that on cloudy days the canopy can only shield NO emission from croplands soil while on sunny days it cannot only prevent NO emission but also assimilate NO through the open leaves stomas. Multiple linear regression analysis indicated that soil temperature was the most important factor in controlling NO emission, followed by fertilizer amount and gravimetric soil water content. About 1.2%, 11.56% and 2.56% of applied fertilizers N were emitted as NO–N and N2O–N from the cabbage, garlic and radish plots, respectively.  相似文献   
243.
为了研究使用随机化Pushover方法进行RC框架结构整体抗震可靠度计算过程中相关参数的适应性,使用Matlab调用SAP2000编制出基于随机化Pushover的结构整体抗震可靠度程序,以一榀11层RC框架结构为例,通过该程序统计出不同参数下结构最大层间位移角的分布情况及整体失效概率,并以大样本实际地震波进行时程分析所统计出的相应结果为基准进行对比。结果表明,在常规参数设置下随机化Pushover方法统计出的最大层间位移角分布情况和结构整体失效概率与大样本时程分析结果有较大差异,然后提出了一种修正方式,有效地减小了两者的差异,并以某算例验证了该修正方式的适用性。  相似文献   
244.
Carbamazepine is frequently detected in waters and hardly eliminated during conventional wastewater treatment processes due to its complicated chemical structure and resistance to biodegradation. A carbamazepine-degrading bacterium named CBZ-4 was isolated at a low temperature (10℃) from activated sludge in a municipal wastewater treatment plant. Strain CBZ-4, which can use carbamazepine as its sole source of carbon and energy, was identified as Pseudomonas sp. by the 16S rRNA gene sequence. The composition and percentage of fatty acids, which can reveal the cold-adaptation mechanism of strain CBZ-4, were determined. Strain CBZ-4 can effectively degrade carbamazepine at optimal conditions: pH 7.0, 10℃, 150 r/min rotation speed, and 13% inoculation volume. The average removal rate of carbamazepine was 46.6% after 144 hr of incubation. The biodegradation kinetics of carbamazepine by CBZ-4 was fitted via the Monod model. Vmax and Ks were found to be 0.0094 hr^-1 and 32.5 mg/L, respectively.  相似文献   
245.
A home-made inexpensive passive diffusion bag (PDB) sampler, prepared by filling deionized water in low-density polyethylene (LDPE) tubes, was evaluated for volatile organic compounds (VOC) sampling in groundwater at industrial contamination sites. Impacts of environmentally relevant conditions on the sampling equilibration time and partitioning of VOCs between the sampler and the water sample were investigated. Sample salinity, agitation and temperature can influence the equilibration time, but generally sampling equilibration was obtained in 14 days under real field sampling of VOCs in groundwater. Both laboratory study and field testing in a contaminated site showed that the VOC concentrations in the developed sampler were equal to those in the water samples at equitibrium. Coupled with a purge and trap concentrator-gas chromatograph-mass spectrometer (P&T-GC-MS), the developed PDB sampler provided a low-cost sampling device for routine monitoring of VOCs in groundwater in wells, with LODs in the range of 2.9-10 μg/L. The proposed PDB was applied to determine VOCs in groundwater at an industrial contamination site, and the present results agreed well with those determined using conventional pump-and-sample monitoring. All the studied 13 VOCs were tested in the four wells in the industrial contamination sites, with their concentrations in the range of 12-73660 μg/L. In addition, while benzene and toluene were heavily contaminated up to a maximum concentration of 74000 μg/L and 6000 μg/L, respectively, 1,2,3-trichlorobenzene and bromobenzene had relatively low contamination levels (below 25 μg/L).  相似文献   
246.
夏季渤海NOx、O3、SO2和CO浓度观测特征   总被引:6,自引:2,他引:6  
利用2000-08~2000-09渤海海上观测资料,初次揭示了渤海污染物浓度的时间变化特点,分析了光照、天气等因素对NOx、O3、SO2和CO气体浓度的影响.SO2浓度比较稳定,浓度平均值在0.006 mg·m-3左右.O3浓度变化主要受辐射影响.在弱天气形势下,CO和NOx浓度分别在2.5~3.5 mg·m-3.和0.1 mg·m-3左右,台风天气会造成浓度在短时间内的剧烈增长.文中还简要说明了渤海大气污染与陆地污染的差异,评价了渤海夏季的空气质量.  相似文献   
247.
微波辐射技术在聚乙烯醇降解反应中的应用   总被引:10,自引:0,他引:10  
考察了微波功率、pH值、H2O2用量和反应时间对聚乙烯醇降解反应的影响.实验表明,在微波辐射条件下,微波功率为800W,辐射时间为1min,pH值为3, H2O2用量为22g H2O2·100g-1 PVA时,5ml聚乙烯醇(7%)的平均聚合度能够在1min内降至67.与常规油浴加热相比,反应速度提高10-20倍.  相似文献   
248.
Near-shore surface sediment was collected from five stations off Redang Island located on the eastern coast of Peninsular Malaysia. Freeze-dried sediments were Soxhlet extracted and then fractionated using column chromatography into aliphatic and polar fractions. Determination of these fractions was carried out using gas chromatography mass spectrometry. The concentration of total resolved aliphatic hydrocarbons in sediments ranged from 157 to 308 ng/g. The distribution of aliphatic fraction showed the presence of n-alkanes ranging from nC15 to nC33 with a minor odd-to-even predominance exhibiting carbon maximum, depending on station, at nC17, nC26, nC29 or nC31. Calculation of Carbon Preference Index (CPI) for CPI15–33 gave values ranging from 1.09 to 1.46. n-Alkanol in all sediment exhibits even-to-odd carbon predominance ranging from nC16 to nC28 and maximising at nC22. n-Fatty acids distribution ranged from nC14 to nC24 with a dominant maximum at nC16 and exhibiting high values of short chain fatty acids (≤nC20) to long chain fatty acids (>nC20) ratios. Unsaturated fatty acids, particularly nC16:1 and nC18:1 is also ubiquitous in all samples. Cholesterol is the most abundant compound amongst the sterol group ranging from 42.8 to 62.6 % of the total sterols. β-Sitosterol, brassicasterol and stigmasterol, are also present but of relatively lower amount. These observations suggest that the aliphatic lipids and sterols in the study area originate, mainly, from biogenic sources of marine microbial with minor contribution from epiticular waxes of terrestrial plants.  相似文献   
249.
为了探索一种高效、快速处理典型挥发性有机物的方法,对微波协同作用下霍加拉特剂催化氧化苯的性能进行了研究,主要考查了微波作用模式、微波功率、苯初始浓度、气体流量、催化剂用量和气体湿度对处理苯效果的影响,并对影响规律进行总结。实验结果表明,微波功率70 W,苯初始浓度1 917 mg/m3,气体流量1.0 L/min,催化剂床层高度3.86 cm时,苯转化率可达99.2%。微波辐照条件下霍加拉特剂能够有效实现苯的催化氧化,并且比传统加热具有更高的能量利用率。  相似文献   
250.
Synthetic musks are ubiquitous pollutants in aquatic environments. As hydrophobic chemicals, they can accumulate in terrestrial and aquatic organisms. Investigations into the bioaccumulation of these chemicals in aquatic ecosystem have, however, been limited, and previous results were inconsistent among species and ecosystem. Studies on this topic have been carried out in European countries, the USA, and Japan, but very few are known of the situation in China. The aim of this study was to investigate contaminant levels of musks in fish from Taihu Lake, the second largest freshwater lake in China, as well as bioaccumulation and biomagnification of the pollutants in the freshwater food chain. Five polycyclic musks and two nitro musks were determined in 24 fish species and nine surface sediment samples from Taihu Lake. HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[γ]-2-benzopyran) and AHTN (7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene) were the predominant contaminants in the fish samples, with concentrations ranging from below the limit of detection (LOD) to 52.9 and from <LOD to 7.5 ng/g lipid weight, respectively. Other contaminants were at low detection frequencies. The results indicated low concentrations of musks yet widespread occurrence of these contaminants in fish from Taihu Lake. Species-specific and lipid-related bioaccumulation characteristics were suggested, but no significant region-specific differences were observed. Normalized biota-sediment accumulation factors for HHCB and AHTN were noted to increase with trophic levels in fish. Trophic magnification factors were estimated at 1.12 for HHCB and 0.74 for AHTN. A biomagnification for HHCB, and probably biodilution for AHTN, in the freshwater food chain are indicated, when trophic magnification factors were concerned. However, the correlations between logarithmic concentrations of the chemicals and trophic levels were not statistically significant. Further study using long food chains in this lake is still needed.  相似文献   
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