一株耐辐射枯草芽孢杆菌的辐照抗性研究

研究室经过对枯草芽孢杆菌黑色变种进行了两次中子辐照,一次γ辐照和一次紫外线辐照,筛选得到了一株辐射抗性较强的菌株,称为耐辐射株.为了系统地考察这株耐辐射株的辐照抗性,分别以芽孢和营养体为材料,研究了其对中子、脉冲X光和紫外线的耐受性.结果显示,这株耐辐射株与原菌相比,对不同射线的耐受性都有不同程度的提高.但对于不同的辐...     

宁波市大气污染概况及影响因素分析

为研究宁波市大气污染状况及其影响因素,利用2013—2018年宁波市国控站点实时监测污染物数据以及气象数据,探讨分析了宁波市大气污染特征以及所受气象因素的影响概况。结果表明：宁波市颗粒物污染和O₃污染呈现典型的季节性特征,颗粒物浓度冬季最高,O₃最大滑动8 h平均质量浓度春、秋季最高。宁波市O₃污染问题越来越突出,且呈现出春、秋季O₃超标天数最多的季节变化特征。O₃小时质量浓度与气温和太阳辐射成正相关关系,NO₂和颗粒物浓度与气温成负相关关系。NO₂与O₃浓度成负相关关系,与颗粒物浓度成正相关关系。     

核技术利用辐射安全监管法律法规解读

随着核技术日益广泛的利用,我国放射性同位素和射线装置技术的应用发展迅速,它在给人类带来巨大利益的同时也带来了辐射危害,安全隐患突出,安全监管任务重。本文就与核技术利用辐射安全监管有关的问题进行法律法规解读,以提高辐射安全监管依法行政能力。     

Prediction of global solar radiation using support vector machines

This article utilizes Support Vector Machines (SVM) for predicting global solar radiation (GSR) for Sharurha, a city in the southwest of Saudi Arabia. The SVM model was trained using measured air temperature and relative humidity. Measured data of 1812 values for the period from 1998–2002 were obtained. The measurement data of 1600 were used for training the SVM, and the remaining 212 were used for comparison between the measured and predicted values of GSR. The GSR values were predicted using the following four combinations of data sets: (i) Daily mean air temperature and day of the year as inputs, and global solar radiation as output; (ii) daily maximum air temperature and day of the year as inputs, and GSR as output; (iii) daily mean air temperature and relative humidity and day of the year as inputs, and GSR as output; and (iv) daily mean air temperature, day of the year, relative humidity, and previous day’s GSR as inputs, and GSR as output. The mean square error was found to be 0.0027, 0.0023, 0.0021, and 7.65 × 10^?4 for case (i), (ii,), (iii), and (iv) respectively, while the corresponding absolute mean percentage errors were 5.64, 5.08, 4.48, and 2.8%. Obtained results show that the SVM method is capable of predicting GSR from measured values of temperature and relative humidity.     

Available solar energy for flat-plate solar collectors mounted on a fixed or tracking structure

The solar energy received by a flat plate collector is calculated for various tracking modes: fixed, inclination depending on the season or the month; variable inclination with fixed azimuth, variable azimuth with fixed inclination and double tracking. At first, we take into account only the sun position and then, we use validated radiation models for estimating the ground solar radiation. Using a tracker is questionable particularly if the additional costs are taken into account. A good solution to increase the available solar energy is to change seasonally the inclination, that is, 4 times per year.     

Evaluation of various global solar radiation models for Nigeria

This study assessed the performance of six solar radiation models. The objective was to determine the most accurate model for estimating global solar radiation on a horizontal surface in Nigeria. Twenty-two years meteorological data sets collected from the Nigerian Meteorological agency and the National Aeronautics and Space Administration for the three regions, covering the entire climatic zones in Nigeria were utilized for calibrating and validating the selected models for Nigeria. The accuracy and applicability of various models were determined for three locations (Abuja, Benin City, and Sokoto), which spread across Nigeria using seven viable statistical indices. This study found that the estimation results of considered models are statistically significant at the 95% confidence level, but their accuracy varies from one location to another. However, the multivariable regression relationship deduced in terms of sunshine ratio, air temperature ratio, maximum air temperature, and cloudiness performs better than other relationships. The multivariable relationship has the least root mean square error and mean absolute bias error, not exceeding 1.0854 and 0.8160 MJ m^?2 day^?1, respectively, and monthly relative percentage error in the range of ± 12% for the study areas.     

某社保(终端/便民/访客)服务器终端EMC整改案例分析

介绍了某社保(终端/便民/访客)服务器终端在电子产品电磁兼容认证中经常遇见的辐射骚扰和传导骚扰测试项目,重点从PCB板级电路EMC设计方面进行测试不合格原因分析,并给出整改对策。并由此案例引出电子产品电磁兼容设计时的注意事项,以图能给电子产品设计工程师提供参考,使其能以较高概率一次性通过EMC认证。     

Hydroxycinnamic acid derivatives in an aquatic liverwort as possible bioindicators of enhanced UV radiation

We examined, under laboratory conditions, the physiological responses of the aquatic liverwort Jungermannia exsertifolia subsp. cordifolia to artificially enhanced ultraviolet (UV) radiation for 82 days, especially considering the responses of five hydroxycinnamic acid derivatives. This species lives in mountain streams, where it is exposed to low temperatures and high UV levels, and this combination is believed to increase the adverse effects of UV. Enhanced UV radiation hardly caused any change in several physiological variables indicative of vitality, such as Fv/Fm and chlorophylls/phaeopigments ratio (OD430/OD410). Thus, this liverwort seemed to be tolerant to UV radiation, probably due to the accumulation of three UV-absorbing hydroxycinnamic acid derivatives: p-coumaroylmalic acid, 5'-(7',8'-dihydroxycoumaroyl)-2-caffeoylmalic acid, and 5'-(7',8'-dihydroxy-7-O-beta-glucosyl-coumaroyl)-2-caffeoylmalic acid. These compounds might serve as bioindicators of enhanced UV radiation.     

京津冀秋冬季工业生产热异常遥感监测探讨

为全面、客观掌握工业生产热排放对大气污染的影响,利用遥感手段分析了2018—2019年秋冬季京津冀工业生产热排放及其同比变化。结果显示:2018—2019年秋冬季,京津冀地区工业热异常点数量及秋冬热异常点辐射功率(FRP秋冬)较上年同期明显增加,工业生产活动规模及强度同比有所扩大,区域PM2. 5浓度呈增长趋势。根据FRP秋冬分布特点可将京津冀工业生产分为3类,密集型、分散型和稀少型。工业生产密集型城市FRP秋冬通常 1 500 MW,较为典型的城市如唐山、邯郸,FRP秋冬可达2 000 MW以上甚至上万MW,这些城市的空气质量也相对较差;保定是工业生产分散型城市,该城市热异常点增长显著,FRP秋冬也可达2 000 MW以上,但空间分布分散;工业生产稀少型城市热异常点较少且空气质量相对较好。     

UV-H2O2工艺对饮用水中 DMP的去除效果和影响因素

采用UV-H2O2工艺对饮用水中内分泌干扰物邻苯二甲酸二甲酯(DMP)的去除进行研究,结果表明,单独的UV或H2O2都不能有效氧化去除DMP;而UV-H2O2联用工艺对饮用水中DMP具有很好的去除效果.在原水DMP浓度为5.1496×10-3mmol·l-1(1.0mg·l-1)左右,UV光强133.9μW·cm-2,H2O2投加量20mg·l-1和反应时间60min条件下,DMP的去除率可达到97.8%.探讨了反应速率常数随影响因素变化的规律,其中H2O2浓度、pH值、DMP初始浓度和本底TOC值对该工艺去除DMP的影响较大.