工业探伤机在野外作业中的辐射防护距离探讨

从技术角度对工业探伤机在野外作业中的辐射防护距离进行了探讨,为探伤企业在工业探伤机野外作业的辐射防护距离提出了更加合理、可行的解决办法。     

苍山5.2级地震前电磁辐射异常

利用枣庄电磁信息台ＤＰＪ Ⅲ、ＵＬＦ Ⅲ及ＪＤ ０３型电磁辐射仪观测到的资料,分析了山东苍山５．２级地震前多数台站记录到的异常信息及其特征。     

对新疆当前电磁辐射环境管理的认识

随着现代科学技术的进步和发展,在电磁辐射的运用范围越来越广的同时其污染水平也在不断增高,人类生存的环境也在不断受到电磁辐射的影响,加强电磁辐射环境管理已势在必行。通信系统电磁辐射应是新疆当前电磁辐射环境管理的重点。     

Cd2+和Pb2+对四环素超声降解性能的影响

通过紫外分光光度法,研究了Cd2+和Pb2+对四环素超声降解过程的影响。研究结果表明,Cd2+和Pb2+在水中与四环素发生络合反应后,在紫外光谱上发生蓝移,在206 nm处产生新的峰值。同时,在低摩尔比(四环素:重金属2+和Pb2+可以加快四环素的超声降解。0.01 mmol/L四环素溶液24 h的超声降解率为7.54%,加入Pb2+和Cd2+离子后,四环素去除率分别升高至20.82%和18.75%。在高摩尔比(四环素:重金属>2)时,Cd2+和Pb2+抑制了四环素的降解,在0.08 mmol/L四环素溶液中,加入Pb2+和Cd2+离子反而使四环素去除率从4.69%分别降低至2.04%和1.40%。     

紫外线消毒后耐药性大肠埃希氏菌的光复活特性

为了考察耐药性大肠埃希氏菌在紫外线消毒后的光复活特性及耐药性的变化,选用从城市污水处理厂分离得到的多重耐药性大肠埃希氏菌SER8作为受试菌株进行紫外线消毒和光复活研究。考察不同剂量紫外线辐照对大肠埃希氏菌SER8的光复活率和光复活速率的影响,以及在磷酸盐缓冲溶液和二沉池出水中复活情况的差别。采用Kirby-Bauer纸片琼脂扩散法考察在紫外线消毒和光复活过程中大肠埃希氏菌SER8对四环素、氨苄西林、诺氟沙星、链霉素、庆大霉素、头孢噻肟、磺胺甲恶唑、环丙沙星和氯霉素的耐药表型。结果表明,在10~40 mJ·cm-2紫外线辐照剂量范围内,大肠埃希氏菌SER8的光复活率和光复活速率基本上随着紫外线辐照剂量的增大而减小。在紫外线消毒后接受日光灯照射的48 h内,大肠埃希氏菌SER8在二沉池出水中的复活率基本与磷酸盐缓冲溶液中的相似,但在48~72 h阶段存在一定的差异。接受20 mJ·cm-2紫外线辐照后经日光灯照射48 h的过程中,大肠埃希氏菌SER8对9种抗生素的耐药表型均未发生变化。     

基于kintecus模型的紫外/次氯酸降解MC-LR的自由基稳态浓度及反应动力学模拟

蓝藻代谢产生的微囊藻毒素-LR(MC-LR)会污染饮用水源,并对人类健康构成威胁。紫外/次氯酸技术能产生氯自由基(Cl·)和羟基自由基(HO·)等强氧化性物质来降解MC-LR。但该技术的最优参数尚不可知,已报导的实验结果仅能提供部分参数,亟需通过数值模拟来确定更多重要参数。因此,采用kintecus化学动力模型模拟了先前报导过的实验数据并对未报导数据进行了预测。结果表明,模型预测值与实验值的变化趋势一致,误差在1.5倍以内。在pH为6时,紫外/次氯酸技术对MC-LR的降解效果最好,7 min左右降解率可达到90%。HO·和Cl·的稳态浓度分别为6.59×10⁻¹⁴ mol·L⁻¹和1.22×10⁻¹⁴ mol·L⁻¹,与原文献实验结果较为吻合(7.89×10⁻¹⁴ mol·L⁻¹,0.93×10⁻¹⁴ mol·L⁻¹)。在次氯酸添加量超过40 μmol·L⁻¹之后,降解效果提升并不明显。当紫外光波长由257.7 nm增加到301.2 nm时,MC-LR的表观降解速率常数由5.07×10⁻³ s⁻¹下降到4.69×10⁻³ s⁻¹,下降了7.5%。而在波长为257.7 nm、pH由6提升至8时,表观降解速率常数由5.07×10⁻³ s⁻¹下降到3.84×10⁻³ s⁻¹,下降了24%。因此,改变pH对降解效率的影响大于改变紫外光波长的情况。     

北京地区冬季重污染期间的雾层特征

大多数针对北京地区冬季重污染过程的研究侧重于气溶胶,关于该过程中雾的研究较少。利用北京南郊观象台L波段探空和地面气象观测资料,以及MODIS和VISSR卫星数据等,对2013年１月12—15日北京地区重污染期间的雾进行分析,发现4 d中共发生2次辐射雾和2次平流雾,每天的雾在类型、垂直分布、形成过程、层结等方面都完全不同：12日清晨为充分发展的辐射雾,辐射雾的生成和发展使近地层稳定层结转变为近中性;13日清晨为2层相连的高空平流雾,分别来自不同源地,平流雾的到来造成近地层雾的消散,也使低层大气扩散能力有所加强;14日清晨出现辐射雾,其发展仅限于初生阶段,生存时间仅约2 h,期间存在贴地逆温;15日清晨为加深的平流雾,较前1天夜间的平流雾,雾顶高度抬升约500 m。鉴于北京地区冬季重污染过程中,雾在形成过程、垂直结构和层结影响等方面呈现出的复杂和多变的状况,针对重污染期间雾层的研究,以及其在垂直扩散和辐射等方面的效应研究都有待加强。

     

The global solar radiation estimation and analysis of solar energy: Case study for Osmaniye,Turkey

This paper investigates the prediction of solar radiation model and actual solar energy in Osmaniye, Turkey. Four models were used to estimate using the parameters of sunshine duration and average temperature. In order to obtain the statistical performance analysis of models, the coefficient of determination (R²), mean absolute percentage error (MAPE), mean absolute bias error (MABE), and root mean square error (RMSE) were used. Results obtained from the linear regression using the parameters of sunshine duration and average temperature showed a good prediction of the monthly average daily global solar radiation on a horizontal surface. In order to obtain solar energy, daily and monthly average solar radiation values were calculated from the five minute average recorded values by using meteorological measuring device. As a result of this measurement, the highest monthly and yearly mean solar radiation values were 698 (April in 2013) and 549 (2014 year) W/m² respectively. On an annual scale the maximum global solar radiation changes from 26.38 MJ/m²/day by June to 19.19 MJ/m²/day by September in 2013. Minimum global solar radiation changes from 14.05 MJ/m²/day by October to 7.20 MJ/m²/day by January in 2013. Yearly average energy potential during the measurement period was 16.53 MJ/m²/day (in 2013). The results show that Osmaniye has a considerable solar energy potential to produce electricity.     

Effects of Electron-Beam Irradiation and Ultraviolet Light (365 nm) on Polylactic Acid Plastic Films

Strips of Ca-I [polylactic acid (PLA) monolayer plastic films from Cargill Dow Polymers LLC, Minnetonka, MN] cut in the machine and nonmachine directions were irradiated with an electron beam using a CIRCLE III Linear Accelerator (MeV Industries S.A., Jouy-en-Josas, Cedex, France). The effects of 33-kGy irradiation on the physical properties of the Ca-I strips were studied. In addition, the effects of ultraviolet (UV) light (365-nm) illumination on the degradation of three PLA plastic films, Ch-I (PLA monolayer plastic films from Chronopol, Golden, CO), GII (PLA trilayer plastic films from Cargill Dow Polymers LLC), MN), and Ca-I (PLA monolayer plastic films from Cargill Dow Polymers LLC) were analyzed by a modified ASTM D5208-91 method. Results showed that irradiation had decreased the weight-average molecular weight (M_w), stress at break, percentage of elongation, and strain energy of Ca-I by 35.5, 26.7, 32.3, and 44.8%, respectively (P < 0.01). The shelf life of the irradiated Ca-I strips at 5°C and <20 ± 5% RH was about 6 months. The degradation rate of Ch-I, GII, and Ca-I with no UV light treatment at 55°C and 10% RH was 2512, 5618, and 3785 M_w/week, respectively. Under the UV light illumination (365 nm), the degradation rate of Ch-I, GII, and Ca-I, was 2982, 8722, and 7467 M_w/week, respectively. Hence, the degradation rate of GII and Ca-I was increased 55 and 97% by UV light (P < 0.008), respectively. This trend was not observed in Ch-I because its starting M_w (78,000 g/mol) was close to the tensile strength lost range (50,000 to 75,000 g/mol) of PLA films. To our knowledge, this is the first study to demonstrate that UV light does further enhance the degradation of PLA films.     

煤灰渣利用中对人群所产生辐射影响的评价

煤的开发与利用产生了大量的灰，渣等固体废物，占用大量土地，污染土壤和水源，成为四大公害之一，因而对煤灰，渣的治理和综合利用一直受到人们的关注。然而，由于煤灰渣中的天然放射性水平较高，因此，在煤灰渣的综合利用，尤其在用作建筑材料时，不可避免地要受到其放射性核素的危害。本文在对四川省各燃煤电厂排放灰渣中的^238U,^232Th,^220R,^40X并无然放射性核素进行分析和研究的基础上，用UNSCEAR1982年报告所推荐的计算模式估算了各电厂煤灰渣制度建材对公众所产生的附加辐射剂量，评价了煤灰制度建材对环境和人群所产生的辐射影响，并提出了控制煤灰渣在建材中的最大掺合量，为其它作用的使用煤灰渣提出了科学的理论依据。