脱硫浆液循环使用造成其组成复杂,尤其是卤族元素易在浆液内积累而较难脱除。氧化态汞水溶性较好,可被湿法脱硫(Wet Flue Gas Desulfurization,WFGD)系统脱除,然而脱硫浆液内已脱除的汞存在二次释放的问题。实验室采用汞在线实时监测方...脱硫浆液循环使用造成其组成复杂,尤其是卤族元素易在浆液内积累而较难脱除。氧化态汞水溶性较好,可被湿法脱硫(Wet Flue Gas Desulfurization,WFGD)系统脱除,然而脱硫浆液内已脱除的汞存在二次释放的问题。实验室采用汞在线实时监测方法对模拟脱硫浆液内卤族元素影响汞释放行为进行系统研究,考察反应温度、卤族元素种类、卤族元素浓度和反应pH对汞释放的影响,并通过模拟计算研究汞释放机理。结果表明,卤族元素对汞释放的抑制能力按Cl<Br<I顺序逐渐增大。提高反应温度有利于降低汞的释放强度,温度由40℃升至60℃时,添加卤族元素的体系汞释放量降幅超20%。增加卤族元素浓度可明显降低汞释放量,当Cl、Br和I物质的量浓度由5 mmol/L升至50 mmol/L后,汞释放量分别降低了23.5%、53.8%和62.8%。增大反应pH后,反应体系的还原电势降低,可减弱中间产物的质子化作用,有利于降低汞释放强度。体系内加入卤族元素后会改变汞的反应路径,汞与卤素生成一系列配合物,减少了汞与体系内还原性物质接触生成不稳定的中间产物HgSO_(3),从而降低汞的释放强度。展开更多
The relative risk(RR)of stroke in patients with hypertension was evaluated by using synthetic index of cerebrovascular hemodynamics.A total of 7,371 patients with hypertension with ages i40 years were selected from a ...The relative risk(RR)of stroke in patients with hypertension was evaluated by using synthetic index of cerebrovascular hemodynamics.A total of 7,371 patients with hypertension with ages i40 years were selected from a population-based cohort study of the risk factors for stroke.The data on the baseline investigation of risk factors,the determination of cerebrovascular hemodynamic parameters(CVHP),and stroke follow-up were analyzed.The RR of stroke in patients with hypertension was evaluated by CVHP scores.Univariate analysis indicated that hypertension,complicated by other risk factors,had significant statistical association with the onset of stroke.RRs for stroke when hypertension complicated with decrease of hemodynamic scores,heart disease,cigarette smoking and alcohol consumption were 4.93(95%CI,3.26–7.45),1.90(95%CI,1.36–2.66),1.99(95%CI,1.42–2.79)and 1.73(95%CI,1.19–2.53)respectively.In multivariate analysis,hemodynamic score,age,sex,cigarette smoking,family history of stroke and systolic blood pressure were selected by the Cox regression for inclusion in the final analysis.Among them,the RR of hemodynamic score was highest.The analysis of doseresponse relationships indicated that when the hemodynamic scores in patients with hypertension were lower than 75 points,the RR of stroke at 75,60,45,30 and 15 points were 2.85,4.43,4.54,5.40 and 9.88,respectively.The risk of stroke in patients with hypertension is closely asso ciated with hemodynamic impairment and the hemodynamic score may be used for quantitative evaluation of relative risks of stroke.展开更多
基金The study was supported by the National Natural Science Foundation of China(Grant No.39370612).
文摘The relative risk(RR)of stroke in patients with hypertension was evaluated by using synthetic index of cerebrovascular hemodynamics.A total of 7,371 patients with hypertension with ages i40 years were selected from a population-based cohort study of the risk factors for stroke.The data on the baseline investigation of risk factors,the determination of cerebrovascular hemodynamic parameters(CVHP),and stroke follow-up were analyzed.The RR of stroke in patients with hypertension was evaluated by CVHP scores.Univariate analysis indicated that hypertension,complicated by other risk factors,had significant statistical association with the onset of stroke.RRs for stroke when hypertension complicated with decrease of hemodynamic scores,heart disease,cigarette smoking and alcohol consumption were 4.93(95%CI,3.26–7.45),1.90(95%CI,1.36–2.66),1.99(95%CI,1.42–2.79)and 1.73(95%CI,1.19–2.53)respectively.In multivariate analysis,hemodynamic score,age,sex,cigarette smoking,family history of stroke and systolic blood pressure were selected by the Cox regression for inclusion in the final analysis.Among them,the RR of hemodynamic score was highest.The analysis of doseresponse relationships indicated that when the hemodynamic scores in patients with hypertension were lower than 75 points,the RR of stroke at 75,60,45,30 and 15 points were 2.85,4.43,4.54,5.40 and 9.88,respectively.The risk of stroke in patients with hypertension is closely asso ciated with hemodynamic impairment and the hemodynamic score may be used for quantitative evaluation of relative risks of stroke.
