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21.
陈卫红 《中国个体防护装备》2011,(6):40-41,46
生产性粉尘是我国作业场所最普遍且严重威胁劳动者健康的职业有害因素,接触生产性粉尘引发的尘肺病是我国发病最高的职业病。为控制尘肺病的发生,以《中华人民共和国职业病防治法》为依据,我国已经进行了大量配套职业卫生标准的研制工作,同时,在生产粉尘健康危害评价、接尘人群的健康监护和呼吸防护用品研制方面开展了大量科研工作。要达到国际劳工组织和世界卫生组织提出的2030年消除矽肺病目标,我们的尘肺防治工作任重道远。 相似文献
22.
Predicting tree diversity across the United States as a function of modeled gross primary production. 总被引:1,自引:0,他引:1
Joanne M Nightingale Weihong Fan Nicholas C Coops Richard H Waring 《Ecological applications》2008,18(1):93-103
At the regional and continental scale, ecologists have theorized that spatial variation in biodiversity can be interpreted as a response to differences in climate. To test this theory we assumed that ecological constraints associated with current climatic conditions (2000-2004) might best be correlated with tree richness if expressed through satellite-derived measures of gross primary production (GPP), rather than the more commonly used, but less consistently derived, net primary production. To evaluate current patterns in tree diversity across the contiguous United States we acquired information on tree composition from the USDA Forest Service's Forest Inventory and Analysis program that represented more than 17,4000 survey plots. We selected 2693 cells of 1000 km2 within which a sufficient number of plots were available to estimate tree richness per hectare. Our estimates of forest productivity varied from simple vegetation indices indicative of the fraction of light intercepted by canopies at 16-d intervals, a product from the MODIS (Moderate Resolution Imaging Spectro-radiometer), to 8- and 10-d GPP products derived with minimal climatic data (MODIS) and SPOT-Vegetation (Systeme Pour l'Observation de la Terre), to 3-PGS (Physiological Principles Predicting Growth with Satellites), which requires both climate and soil data. Across the contiguous United States, modeled predictions of gross productivity accounted for between 51% and 77% of the recorded spatial variation in tree diversity, which ranged from 2 to 67 species per hectare. When the analyses were concentrated within nine broadly defined ecoregions, predictive relations largely disappeared. Only 3-PGS predictions fit a theorized unimodal function by being able to distinguish highly productive forests in the Pacific Northwest that support lower than expected tree diversity. Other models predicted a continuous steep rise in tree diversity with increasing productivity, and did so with generally better or nearly equal precision with fewer data requirements. 相似文献
23.
宁波市城市污水处理厂污泥处置方案探讨 总被引:2,自引:0,他引:2
随着城市污水处理率提高导致的污水污泥产量的增长趋势也使得污水污泥的处理问题更为突出。在总结国内外城市污泥处置技术发展趋势的基础上,结合宁波市的实际情况,根据无害化、减量化和资源化的原则,提出城市污泥近远期处置方案,并对处置方案作出可行性分析。 相似文献
24.
PAC-chitosan复合絮凝剂中铝形态 总被引:1,自引:1,他引:0
以不同碱化度(B)的聚合氯化铝(PAC)和不同粘度的壳聚糖为原料制备出一系列PAC-chitosan复合絮凝剂。采用Al-Ferron逐时络合比色法研究了PAC-chitosan复合絮凝剂中铝的形态分布,探讨了PAC的B值、壳聚糖的含量(C)和粘度(η)对复合絮凝剂中铝的形态分布的影响。结果表明:壳聚糖与PAC之间发生了一定的相互作用,通过试验结果推断出当B=1.5,壳聚糖粘度η=800 Pa·s,C=0.6 mg/mL絮凝效果最佳。并用某造纸废水进行了烧杯絮凝试验。絮凝试验结果与推断结果相一致。 相似文献
25.
制药行业VOCs排放组分特征及其排放因子研究 总被引:1,自引:0,他引:1
为研究制药行业产品工艺过程的挥发性有机物(VOCs)排放特征,以华东地区某工业园区的两家化学合成类制药企业为研究对象,采集并分析了来自不同生产线和生产环节的VOCs样品.结果表明,同行业不同企业、同企业不同车间的VOCs排放特征差异显著,基于获得的产品生产线不同环节的VOCs排放特征,结合产品工艺流程,推测排放的VOCs组分主要与原料和生产工序有关;处理设施对不同VOCs组分的脱除效率也存在明显差别,RTO对不同VOCs种类的处理效率由高至低依次为OVOCs(80.5%)、芳香烃(72.7%)、烷烯烃(68.3%)和卤代烃(66.1%);根据浓度测试结果,计算得到48种VOCs的排放量和排放因子,制药企业A和B的VOCs排放总量分别为14.2 t·a-1和0.4 t·a-1,均以卤代烃占比最大,分别为56.1%和48.2%. 相似文献
26.
不同温度下微生物和纤维素酶对发酵猪粪理化特性的影响 总被引:3,自引:0,他引:3
采用恒温发酵培养试验,研究了5℃和25℃时分别接种纤维素酶(X)、枯草芽孢杆菌(K)和EM菌(E)及其组合对新鲜猪粪发酵中的全氮、铵态氮、有机质、p H及微生物数量的影响.结果表明,5℃条件下,猪粪中微生物生长受抑制,细菌、真菌、放线菌数量均明显低于25℃,发酵终期猪粪有机质含量为70%~83%,p H值为7.16~7.36;25℃条件时,发酵终期猪粪有机质含量降至61%~72%,p H值升至8.09~8.94.与对照相比较,25℃下添加微生物和纤维素酶的处理有机质含量降低了2.95%~7.70%(除了K和XE处理),C/N值降低了4.04%~37.59%(除了XK处理),p H值增加了1.7%~26.8%.在总的添加量一致的条件下,发酵剂组合KE、XE、XK、XKE对猪粪发酵的效果优于单一发酵剂的X、K、E处理. 相似文献
27.
Adsorption characteristic of bensulfuron-methyl at variable added Pb^2+ concentrations on paddy soils 总被引:1,自引:0,他引:1
WU Weihong WANG Haizhen XU Jianming XIE Zhengmiao 《环境科学学报(英文版)》2009,21(8):1129-1134
The combined pollution of heavy metal Pb2+ and bensulfuron-methyl (BSM), originating from chemical herbicides, in agroecological environments has become commonplace in southern China. The adsorption of BSM on three paddy soils in the presence of Pb2+ was examined using high-performance liquid chromatograph (HPLC). Results indicated that adsorption of BSM could accurately be described by a Freundlich isotherm equation with correlation constant (R) > 0.98, irrespective of the presence of spiked Pb2+. Of the various factors influencing BSM sorption, soil pH appeared to be the most influential. The constant Kf of Freundlich isotherm equation tended to increase with increasing Pb2+ concentration in soil which indicated that the spiked of Pb2+ in paddy soils would promote the sorption of BSM. ΔGθ of BSM in three paddy soils was less than 40 kJ/mol in all treatments, indicating the adsorption of BSM is mainly physical in nature. The elution of soil dissolved organic matter (DOM) enhanced the adsorption of BSM in paddy soils. The mechanisms involved in the promotion effects of the spiked Pb2+ on BSM adsorption might be the modified surface characteristics of paddy soil solids due to the soil acidification and the increase of soil organic matter concentration because of DOM binding. 相似文献
28.
肥水养殖显著增加了长寿湖底泥中的磷含量。为了解肥水养殖积累在湖泊底泥中磷的释放情况,以长寿湖大坝口枯水期底泥为实验材料,模拟研究了不同环境条件(上覆水pH、温度、DO含量和扰动)下湖泊底泥的释磷特征。结果表明,在弱碱性条件下,底泥释磷量随上覆水pH的升高而升高;温度升高有利于底泥磷的释放,温度每升高5℃,第21天时底泥释磷量增大0.0045~0.0074 mg/L;DO含量降低有利于底泥中铁/铝结合态磷的释放;扰动对底泥磷的释放没有明显影响。研究表明,网箱养殖增加了底泥中的有机磷含量,促进有机磷向无机磷转化,增大了底泥中磷的释放风险。 相似文献
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