核电厂流出物排放氚的化学类别及监测方法

本文对核电厂液态流出物和气载流出物排放氚的化学类别进行了分析,根据调研给出了可能的排放量。结合对环境生物、空气中氚的监测经验,分析了开展核电厂液态流出物和气载流出物中不同化学类别氚监测的可行性。最后提出了开展相关监测和剂量评估模式改进的有关建议。

核电厂流出物排放氚的化学类别与监测方法研究

本文对核电厂液态流出物和气载流出物排放氚的化学类别进行了分析,根据调研给出了可能的排放量。结合对环境生物、空气中氚的监测经验,分析了开展核电厂液态流出物和气载流出物中不同化学类别氚监测的可行性。最后提出了开展相关监测和剂量评估模式改进的有关建议。

试论化学危险品储运的安全管理

化学危险品的种类繁多,性质各异,在储存运输中存在着极大的风险。不同的化学危险品具有不同的性质特点,根据化学危险品的性质特点,不同的化学危险品采用分库、分类、分区的办法储存养护和专车专业运输的办法,可以把危险的风险降低到最低限度。化学危险品储运安全管理的关键是以预防为主,危险品包装、仓储养护、车辆设备、人员资质等必须达到国家规定的标准,只有这样,才能防止重大事故的发生。

36种典型除草剂对绿藻的毒性研究

近年来,农药对生态系统的初级生产者——藻类的毒性及其生态毒理学研究引起了国内外学者的广泛关注。除草剂在生产中广泛应用,对藻类的毒性作用最强,其毒性效应远高于杀虫剂和杀菌剂。论文选择市场上具有典型代表性的36种除草剂原药,分析解读除草剂在国内的登记情况,以及在作物、旱田和水田的使用情况;明晰对藻类生长抑制急性毒性效应。结果表明:1)除草剂的作用方式和化学类别对绿藻毒性影响显著;对于抑制植物细胞分裂和作用于植物叶绿体的除草剂对绿藻毒性均较高,以人工合成植物生长素为代表的除草剂对绿藻毒性均较低;2)相同作用方式,不同化学类别的除草剂,对单一绿藻的毒性差异明显。在水稻上获得登记的除草剂对藻类毒性整体低于在旱田获得登记的除草剂对藻类的毒性。开展多种农药对水生生态毒性的研究,为农药的合理安全使用、农药在淡水环境中的生态效应评价以及保护淡水生态系统提供科学依据。

Machine learning strategies for lithostratigraphic classification based on geochemical sampling data: A case study in area of Chahanwusu River, Qinghai Province, China

Based on the complex correlation between the geochemical element distribution patterns at the surface and the types of bedrock and the powerful capabilities in capturing subtle of machine learning algorithms,four machine learning algorithms,namely,decision tree(DT),random forest(RF),XGBoost(XGB),and LightGBM(LGBM),were implemented for the lithostratigraphic classification and lithostratigraphic prediction of a quaternary coverage area based on stream sediment geochemical sampling data in the Chahanwusu River of Dulan County,Qinghai Province,China.The local Moran’s I to represent the features of spatial autocorrelations,and terrain factors to represent the features of surface geological processes,were calculated as additional features.The accuracy,precision,recall,and F1 scores were chosen as the evaluation indices and Voronoi diagrams were applied for visualization.The results indicate that XGB and LGBM models both performed well.They not only obtained relatively satisfactory classification performance but also predicted lithostratigraphic types of the Quaternary coverage area that are essentially consistent with their neighborhoods which have the known types.It is feasible to classify the lithostratigraphic types through the concentrations of geochemical elements in the sediments,and the XGB and LGBM algorithms are recommended for lithostratigraphic classification.

Identification of variety of rice and determination of content of each rice in mixtures of two rices by nonlinear chemical analysis

Fingerprints of two varieties of rice and their mixtures were investigated by a nonlinear chemical reaction system consisting of rice components,sodium bromate,manganese sulfate,sulfuric acid and acetone.The variety of rice was identified by the visual characteristic of fingerprint and system similarity pattern recognition,and the content of each variety of rice in the mixture was determined by the quantitative information of fingerprint.The results show that nonlinear chemical analysis may be used to exactly identify the variety of pure rice and to accurately determine the content of each variety of rice in the mixture,indicating the method is simple and convenient.

Genetic identification of two species of Pleuronichthys by DNA barcoding

DNA barcoding is a new method for biological taxonomy, offering the ability to identify species from fragments in any life-history stage. Pleuronichthys cornutus and P. japonicus are two morphologically similar species. Pleuronichthys japonicus has never been found previously in China. However, in this study, we identified both species using DNA barcoding （cytochrome c oxidase subunit I （COI））, the mtDNA control region and cytochrome b. The results reveal that： l） intraspecific variation in the DNA barcode is much less than interspecific variation; 2） the two morphologically similar species were placed into separate clades distinguishable by high bootstrap values; 3） COI barcodes are more powerful for identifying the two species than the other two mtDNA fragments.

Carob Origin Classification by FTIR Spectroscopy and Chemometrics

The goal of this study was to use Fourier transform mid-infrared （FTIR） spectroscopy for discrimination of samples of pods and seeds of carob from three Moroccan regions. The origin of samples Pods and seeds of carob could be distinguished from their IR spectra and this measurement was used for discriminate analysis. A multivariate analysis procedure based on the combined use of Hierarchical Cluster Aanalysis （HCA） and Partial Least Squares-Discriminant Analysis （PLS-DA） was tested and provided good classification results. Three distinctive clusters were recognised, related to the three Moroccan regions. Afterwards, PLS-DA was used for the discrimination and classification of the origin of the various Pods and seeds of carob samples. The results demonstrated that the combined use of FTIR and chemometric analysis （cluster analysis and discrimination by PLS- DA） can be used to rapidly and simply determine the origin of carob pulpe samples.

Study of Substrate and Physico-Chemical Base Classification of the Rivers of Nepal

The rivers in Nepal are classified in terms of geographical regions but a more scientific classification such as on the ba-sis of morphology is clearly lacking. This study was done in 9 rivers namely Jhikhukhola of the Koshi system, Aandhikhola, Arungkhola, East Rapti, Karrakhola, Seti and main channel Narayani of the Gandaki system, and two independent systems within Nepal, Bagmati and Tinau. Among the morphologies, river bed or the substratum was taken as the main variable for the analysis which was categorized into 7 types as rocks, boulders, cobbles, pebbles, gravels, sand and silt. There were 23 sampling sites each with 2 stretches of around 100m in those rivers. The data were taken as a percentage, and to avoid biases it was observed visually by the same person for a complete year in every season. With 23 sites each with 2 stretches and 4 replicates corresponding to 4 seasons, there are altogether 184 observations, each termed as a case, that constitute this work. Canonical Discrimination Analysis (CDA) which is most suitable when the data pool is huge was applied to see if the rivers studied distinguish themselves in terms of its morphology. The result was remarkably successful and was close to the established regional classification of the rivers. This kind of river classification has great application in the utilization, conservation and restoration of the most important natural re-source of the country.