Anaerobic digestion of organic fraction of municipal solid waste combining two pretreatment modalities, high temperature microwave and hydrogen peroxide

In order to enhance anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW), pretreatment combining two modalities, microwave (MW) heating in presence or absence of hydrogen peroxide (H₂O₂) were investigated. The main pretreatment variables affecting the characteristics of the OFMSW were temperature (T) via MW irradiation and supplemental water additions of 20% and 30% (SWA20 and SW30). Subsequently, the focus of this study was to evaluate mesophilic batch AD performance in terms of biogas production, as well as changes in the characteristics of the OFMSW post digestion. A high MW induced temperature range (115-175 °C) was applied, using sealed vessels and a bench scale MW unit equipped with temperature and pressure controls. Biochemical methane potential (BMP) tests were conducted on the whole OFMSW as well as the liquid fractions. The whole OFMSW pretreated at 115 °C and 145 °C showed 4-7% improvement in biogas production over untreated OFMSW (control). When pretreated at 175 °C, biogas production decreased due to formation of refractory compounds, inhibiting the digestion. For the liquid fraction of OFMSW, the effect of pretreatment on the cumulative biogas production (CBP) was more pronounced for SWA20 at 145 °C, with a 26% increase in biogas production after 8 days of digestion, compared to the control. When considering the increased substrate availability in the liquid fraction after MW pretreatment, a 78% improvement in biogas production vs. the control was achieved. Combining MW and H₂O₂ modalities did not have a positive impact on OFMSW stabilization and enhanced biogas production. In general, all samples pretreated with H₂O₂ displayed a long lag phase and the CBP was usually lower than MW irradiated only samples. First order rate constant was calculated.     

某省医用电子直线加速器治疗室辐射环境监测分析

通过对省内医用电子直线加速器辐射环境监测,对比不同等级医院医用电子直线加速器辐射防护水平的差异,为放射治疗工作正常开展提供放射防护数据参考,确保放射工作人员、受检者及公众健康安全.按照标准方法采用辐射剂量仪AT1123及中子周围剂量当量仪BH3105E对加速器治疗室周围环境进行光子及中子的监测,采用热释光法对放疗科放射...     

20个小麦品种对UV-B辐射增强响应的形态学差异

研究了大田栽培和自然光条件下 ,模拟UV -B辐射增强对 2 0个小麦品种影响的形态学差异。结果表明 ,叶面积指数、株高、节间长、茎基粗对UV -B辐射增强响应具有品种间差异。株高和节间长对UV -B辐射响应具有一致性 ,呈极显著正相关。根据形态响应指数 (MRI) ,耐性品种 (MRI>- 8 5 )为 :辽春 9>文麦 3>大理 90 5 >兰州 80 10 1>绵阳 2 6 >YV 97- 31>毕 90 - 5。敏感品种 (MRI <- 49 4)为 :会宁 18>繁 19>楚雄 880 7>My 94- 9>黔 14>云麦 39>陇春 16。耐性品种具有较小的叶展开角度 ,敏感品种具有较大的叶展开角度。UV -B辐射还不同程度抑制小麦条锈病的发生     

微波消解-ICP/MS法同时测定水产品中13种元素

用硝酸-双氧水体系微波消解,以In、Sc为内标,采用电感耦合等离子体质谱法（ICP／MS）同时测定水产品中V、Cr、C0、Ni、Cu、Zn、As、Se、Cd、Sb、Ba、T1、Pb等13种元素。各元素的检出限在0．05ng／g～0．064μg／g之间,样品平行测定4次的RSD〈5％,鲢鱼样品的加标回收率在81％～117％之间。     

微波消解-原子荧光法测定环境空气中的砷

建立了浸渍滤膜吸附-微波消解-原子荧光法测定环境空气中的砷的方法,改进了原有的采样方法,有效地克服了原方法中湿法消解的缺点,并大大降低了检出限,能够满足《环境空气质量标准》（GB3095—2012）中对砷排放的参考浓度限值要求。     

微波消解-石墨炉原子吸收分光光度法测定海洋沉积物中镉和铬

以硝酸作为消解液,采用微波消解仪对海洋沉积物进行消解,用石墨炉原子吸收分光光度法测定消解液中的Cd和Cr。该方法在0μg/L~10.0μg/L范围内线性良好,Cd和Cr的方法检出限分别为0.04 mg/kg和2.0 mg/kg,实际样品的加标回收率在96.0%~100%之间,RSD为0.3%~5.2%。用该方法与国标法同时测定北部湾海域海洋沉积物实际样品,结果无明显差异,而该方法处理样品更为省时省力。     

医用电子直线加速器室辐射屏蔽防护设计

在满足《电离辐射防护与辐射安全基本标准》（GB18871—2002）的同时,合理设计医用加速器室的辐射屏蔽防护。以《电离辐射防护与辐射安全基本标准》（GB18871—2002）为准则,运用电离辐射屏蔽原理、计算方法,根据安装的医用加速器所具有的辐射物理特点和辐射防护的发展需求,对所有产生的射线进行严谨、规范和优化的屏蔽计算。结果表明,辐射屏蔽防护符合我国医用加速器机房使用标准。     

微波萃取-气相色谱法测定土壤中有机氯残留

采用微波萃取-硅镁吸附剂净化-气相色谱法测定土壤中有机氯农药,优化了试验条件。方法线性良好,8种有机氯农药的检出限为0.09ng／g-0.62ng／g,样品测定的RSD为2.6％-13.2％,基质加标平均回收率为93.7％-112％,质控样的测定结果与参考值相吻合。     

微波消解-电感耦合等离子体质谱法同时测定废水中20种元素

采用微波消解-电感耦合等离子体质谱法,同时测定了废水中Be、V、Cr、Mn、Co、Ni、Cu、Zn、As、Se、Mo、Ag、Cd、Sb、Ba、Hg、Tl、Pb、Th、U等20种元素,比较了5种不同消解体系对废水样品的加标回收结果,确定采用硝酸+过氧化氢消解体系。Hg在0.050μg/L～2.00μg/L、其他元素在5.00μg/L～500μg/L范围内线性良好,检出限为0.01μg/L～0.2μg/L,国家有证标准物质的测定结果符合要求,废水样品平行测定的RSD为2.6%～6.5%,加标回收率为84%～110%。     

微波消解ICP-MS法同时测定大气颗粒物中多种痕量元素

采用微波消解电感耦合等离子体质谱法同时测定大气颗粒物中13种元素,选择硝酸体系消解20 min,硝酸加入体积为8 mL。Cu、Ni、Cr、Pb、Al、Mg、Mn、Ca在0μg/L～100μg/L,Ag、Ba、Co、Cd、Sn在0μg/L～5.00μg/L范围内线性良好,除Al、Mg、Ca检出限较高外,其他10种元素的检出限为0.07 ng/m3～1.82 ng/m3(按采样体积0.688 m3、定容体积50 mL计),滤膜样品平行测定3次的RSD≤1.2%,加标回收率在92%～108%之间。