226Ra in Tap and Mineral Water and Related Health Risk in the Republic of Croatia

The presence of 226Ra in drinking water may sometimes make important contribution to natural background radiation exposures. The paper describes the study of 226Ra content in drinking water of Croatia: tap water from the public supply system of several major towns and bottled mineral water from two selected mineral water springs. 226Ra was determined by alpha-spectrometric measurement after radiochemical separation. The radiation doses originating from drinking tap water and bottled mineral water were estimated. The annual dose from consumption of bottled mineral water was compared to that received from ingestion of public system tap water. The study showed that 226Ra content for investigated categories of waters is below the levels at which any unacceptable dose due to ingestion would arise.     

电化学氧化法降解马拉硫磷废水的研究

研究了在单独电解作用下及超声辐射．电解联合作用下，降解马拉硫磷农药废水的不同效果，详细探讨了电解时间、酸碱性、电压、电流及加入电解质的量等因素对结果的影响。实验结果表明，马拉硫磷农药废水在电解单独作用下，COD去除率可达到86．86％；在超声辐射-电解联合作用下，COD去除率可达到91．53％。     

BLEVE火球热辐射及其影响评价模型介绍

高压液化易燃、易爆化学品储罐易发生BLEVE,引起热辐射,会造成周围人员伤亡和设备损坏.介绍了BLEVE火球热辐射及其影响模型,通过该模型可以计算BLEVE火球的尺寸、持续时间、升空高度、热辐射通量及预测暴露在BLEVE火球热辐射通量下人的致死概率.     

火球热辐射后果计算动态模型的应用

为了精确地评估火球的热辐射后果,需要深入研究火球热负荷对影响区域暴露人员所造成的伤害.详细介绍了具有时间属性的火球热辐射动态模型,以实例描绘了火球直径、高度以及目标接受到的热通量等火球参数的动态变化规律.结果表明:具有时间属性的火球热辐射动态模型计算出的热辐射值小于静态模型计算的值,动态模型有可能更准确地描述火球参数的实际动态变化,进而合理地确定火球热辐射的人员伤亡区域,并为过热可燃液体容器的安全设计及风险分析提供一种新的后果评估技术及方法.     

手机基站电磁辐射问题释疑

本文就社会普遍关心的手机基站电磁辐射对人体健康的影响问题,从基站电磁辐射属性,强度,对人体健康的影响等,作了较为详细的论述。     

环境辐射有关问题的讨论

本文论述了与环境辐射有关的问题。根据其剂量当量和危险水平,讨论了公众剂量限值的实践性     

UV-B辐射增强与1,2,4-三氯苯污染复合胁迫对青菜生长的影响

采用盆栽实验,分析了单一UV-B辐射增强或1,2,4-三氯苯(TCB)污染土壤与两种胁迫复合作用对青菜生长发育、气孔阻力及叶片结构的影响.结果表明,单一1,2,4-TCB污染对青菜生长发育的抑制作用大于两种胁迫复合作用.UV-B辐射增强和1,2,4-TCB污染均显著增加青菜叶片正面和反面气孔阻力.UV-B辐射增强使青菜叶片产生白化现象.1,2,4-TCB污染使叶片颜色变淡,并使青菜叶片表面出现黑斑症状,且UV-B辐射增强使黑斑症状加剧.总之,单一增强UV-B辐射或1,2,4-TCB污染及其复合作用对青菜各生长发育指标的影响结果不同.     

Photocatalytic degradation of Rhodamine B bymicrowave-assisted hydrothermal synthesized N-doped titanate nanotubes

Microwave-induced nitrogen-doped titanate nanotubes（NTNTs） were characterized by transmission electron microscopy（TEM）, X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）, Fourier transform infrared spectroscopy（FT-IR）, Zeta potential analysis,specific surface area（SBET）, and UV-Visible spectroscopy. TEM results indicate that NTNTs retain a tubular structure with a crystalline multiwall and have a length of several hundred nanometers after nitrogen doping. XRD findings demonstrate that the crystalline structure of NTNTs was dominated by anatase, which is favored for photocatalytic application. The Ti-O-N linkage observed in the XPS N 1s spectrum is mainly responsible for narrowing the band gap and eventually enhancing the visible light photoactivity. FT-IR results demonstrated the existence of H3O＋, which could be excited by photo-generated holes to form hydroxyl radicals and degrade environmental pollutants. After sintering at 350°C, the UV-Vis absorbance edges of NTNTs significantly shift to the visible-light region, which indicates N atom doping into the nanotubes. Photocatalytic degradation of Rhodamine B（RhB） via NTNTs show good efficiency, with pseudo first-order kinetic model rate constants of 3.7 × 10-3, 2.4 × 10-3and 8.0 × 10-4sec-1at pH 3, 7, and 11, respectively.     

Radiation induced decomposition of a refractory cefathiamidine intermediate

Diisopropylthiourea（DPT）, an intermediate of a widely used cephalosporin, has been found to be one of the most refractory components in cephalosporin synthesis wastewater.This compound cannot be completely removed by conventional biological processes due to its antimicrobial property. Ionizing radiation has been applied in the decomposition of refractory pollutants in recent years and has proved effective. Therefore, the decomposition of DPT by γ-irradiation was studied. The compound was irradiated at the dose of 150–2000 Gy before a change of concentration and UV absorption of the solutions was detected.Furthermore, the decomposition kinetics and radiation yield（G-value） of DPT was investigated. The results of radiation experiments on DPT-containing aqueous showed that the DPT can be effectively degraded by γ-radiation. DPT concentration decreased with increasing absorbed doses. G-values of radiolytic decomposition for DPT（20 mg/L） were 1.04 and 0.47 for absorbed doses of 150 and 2000 Gy, respectively. The initial concentration and p H of the solutions affected the degradation. As the concentration of substrate increased,the decomposition was reduced. The decrease of removal rate and radiation efficacy under alkaline condition suggested that lower p H values benefit the γ-induced degradation. UV absorption from 190 to 250 nm decreased after radiation while that from 250 to 300 nm increased, indicating the formation of by-products.     

脱水污泥热干化和微波干化过程及机理比较分析

以脱水污泥为原料,分别采用恒温热干化和微波干化2种不同的方法考察脱水污泥的干化情况;对不同干化阶段的污泥进行显微观察,分析干化过程;并对2种干化过程的机理进行了探讨。实验结果表明随着加热温度的升高,污泥中水分脱除速度加快。加热温度低于100℃时,在120 min以内,热干化无法达到较高的脱水率。加热温度在140℃以上,加热时间120 min时,脱水污泥的脱水率可达到98.26%。微波干化法在功率为500~900 W,5~10 min内可使脱水污泥的脱水率到达99.20%以上。机理分析表明热干化传质与传热方向相反,微传热和传质的方向相同,因此微波干化具有更快速、高效的特点。