什么是放射源

指用放射性物质制成的能产生辐射照射的物质或实体。按其密封状况可分为密封源和非密封源。密封源是密封在包壳或紧密覆盖层里的放射性物质,工农业生产中应用的料位计、探伤机等使用的都是密封源,如钴-60、铯-137、铱-192等。非密封源是指没有包壳的放射性物质,医院里使用的放射性示踪剂属于非密封源,-碘131、碘-125、锝-99m等。放射源发射出来的射线具有一定的能量,它可以破坏细胞组织,重则死亡,轻则伤人肌体。     

公民反恐防范小常识(连载一)

正常见的恐怖袭击手段有哪些常规手段:1.袭击爆炸恐怖袭击。炸弹爆炸、汽车炸弹爆炸、自杀性人体炸弹爆炸等;枪击恐怖袭击。手枪射击、制式步枪或冲锋枪射击等。2.劫持劫持人,劫持车辆、船、飞机等。3.破坏纵火破坏及破坏电力、交通、通讯、供气供水设施等。非常规手段:1.核与辐射恐怖袭击通过核爆炸或放射性物质的散布,造成环境污染或使人员受到辐射照射。2.生物恐怖袭击利用有害生物或有害生物产品侵害人、农作物、家畜等,如发生在美国"911"事件以后的炭疽邮件事件。     

如何防范核辐射

应急状态下为避免或减少工作人员和公众可能接受的核辐射剂量,可采取一定的应急防护措施,如隐蔽、撤离、服碘防护、通道控制、食物和饮水控制、去污,以及临时避迁、永久再定居等。隐蔽是指人员停留在或进入室内,并闭门窗及通风系统;撤离是指将人们由受影响地区紧急转移,以避免或减少来自烟雨或高水平放射性沉积物引起的大剂量照射。     

注意让你家的食物归队

牛奶:躲着光线储藏。光线不仅能杀菌,也会"杀死"牛奶中的营养素。研究发现,牛奶直接暴露在阳光下4分钟就会酸化、变质;在超市冷藏柜的灯光下,其"最佳保鲜期"也只有4小时左右。台湾林口长庚医院营养师张丽玲透露,牛     

20个驾驶误区要不得

1、夜晚远光灯越强行驶越安全。错误，灯光的照射角度越大越安全，灯光抬得越高越亮越危险。[第一段]     

辐射防护

辐射有什么危害 人们在长期的实践和应用中发现，少量的辐射照射不会危及人类的健康，过量的放射性射线照射对人体会产生伤害，使人致病、致死。剂量越大，危害越大。     

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     

Abiotic degradation of four phthalic acid esters in aqueous phase under natural sunlight irradiation

Abiotic degradability of four phthalic acid esters (PAEs) in the aquatic phase was evaluated over a wide pH range 5–9. The PAE solutions in glass test tubes were placed either in the dark and under the natural sunlight irradiation for evaluating the degradation rate via hydrolysis or photolysis plus hydrolysis, respectively, at ambient temperature for 140 d from autumn to winter in Osaka, Japan. The e ciency of abiotic degradation of the PAEs with relatively short alkyl chains, such as butylbenzyl phthalate (BBP) and di-nbutyl phthalate (DBP), at neutral pH was significantly lower than that in the acidic or alkaline condition. Photolysis was considered to contribute mainly to the total abiotic degradation at all pH. Neither hydrolysis nor photolysis of di-ethylhexyl phthalate (DEHP) proceeded significantly at any pH, especially hydrolysis at neutral pH was negligible. On the other hand, the degradation rate of diisononyl phthalate (DINP) catalyzed mainly by photolysis was much higher than those of the other PAEs, and was almost completely removed during the experimental period at pH 5 and 9. As a whole, according to the half-life (t1=2) obtained in the experiments, the abiotic degradability of the PAEs was in the sequence: DINP (32–140 d) > DBP (50–360 d), BBP (58–480 d) > DEHP (390–1600 d) under sunlight irradiation (via photolysis plus hydrolysis). Although the abiotic degradation rates for BBP, DBP, and DEHP are much lower than the biodegradation rates reported, the photolysis rate for DINP is comparable to its biodegradation rate in the acidic or alkaline condition.     

利用光线识假酒

苏格兰的研究人员近日宣布,他们可以使用光线来鉴别出苏格兰威士忌的品牌和年份。目前假酒被认为是酿酒业的一个主要问题,人们一直在寻求鉴别真伪的方法。研究人员表示,这个测试只需使用一小滴样本,便可鉴别出威士忌酒的真伪。