Aquatic photolysis of hydroxylated polybromodiphenyl ethers under direct UV irradiation: a case study of 2′-HO-BDE-68

Environmental Science and Pollution Research - Hydroxylated polyhalodiphenyl ethers (HO-PXDEs) have attracted considerable scientific interest as examples of emerging aquatic pollutants. However, a...     

Simple model for estimating dry deposition velocity of ozone and its destruction in a polluted nocturnal boundary layer

Determining the destructions of both ozone and odd oxygen, O_x, in the nocturnal boundary layer (NBL) is important to evaluate the regional ozone budget and overnight ozone accumulation. This work develops a simple method to determine the dry deposition velocity of ozone and its destruction at a polluted nocturnal boundary layer. The destruction of O_x can also be determined simultaneously. The method is based on O₃ and NO₂ profiles and their surface measurements. Linkages between the dry deposition velocities of O₃ and NO₂ and between the dry deposition loss of O_x and its chemical loss are constructed and used. Field measurements are made at an agricultural site to demonstrate the application of the model. The model estimated nocturnal O₃ dry deposition velocities from 0.13 to 0.19 cm s^?1, very close to those previously obtained for similar land types. Additionally, dry deposition and chemical reactions account for 60 and 40% of the overall nocturnal ozone loss, respectively; ozone dry deposition accounts for 50% of the overall nocturnal loss of O_x, dry deposition of NO₂ accounts for another 20%, and chemical reactions account for the remaining 30%. The proposed method enables the use of measurements made in typical ozone field studies to evaluate various nocturnal destructions of O₃ and O_x in a polluted environment.     

Process,Characterization and Biodegradability of Aliphatic Aromatic Polyester/Sisal Fiber Composites

The biodegradability, morphology, and mechanical properties of composite materials made of Poly(butylene adipate-co-terephthalate) (PBAT) and sisal fiber (SF) were evaluated. Composites containing acrylic acid-grafted PBAT (PBAT-g-AA/SF) exhibited noticeably superior mechanical properties due to greater compatibility between the two components. The dispersion of SF in the PBAT-g-AA matrix was highly homogeneous as a result of ester formation between the carboxyl groups of PBAT-g-AA and hydroxyl groups in SF and the consequent creation of branched and cross-linked macromolecules. Each composite was subjected to biodegradation tests in Rhizopus oryzae compost. Morphological observations indicated severe disruption of film structure after 60 days of incubation, and both the PBAT and the PBAT-g-AA/SF composite films were eventually completely degraded. Water resistance of PBAT-g-AA/SF was higher than that of PBAT/SF, although weight loss of composites buried in Rhizopus oryzae compost indicated that both were biodegradable, even at high levels of SF substitution. The PBAT-g-AA/SF films were more biodegradable than those made of PBAT, implying a strong connection between these characteristics and biodegradability.     

高台位旱地石灰性紫色土培肥研究

本文研究了高台位旱地石灰性紫色土的肥力退化因子,并针对紫色母岩矿质养分丰富、易风化成土的特点,以一种培肥耕作法-聚土免耕耕作法培肥土壤。结果表明,采用此耕作法的土壤具有防蚀、抗旱、培肥和自调能力,能提高系统生产力。     

改性脲醛树脂絮凝浮选剂在污水处理中的应用

用尿素和甲醛作为主要原料合成脲醛树脂季胺盐和脲醛树脂叔胺盐。采用ＷＥＭＣＯ浮选模型机和自行设计的模拟现场充气浮选的气浮设备及现场污水对絮凝浮选剂除油、除悬浮物的性能进行了评价。另外，用核磁共振和红外光谱测定了脲醛树脂叔胺盐的结构，并用凝胶色谱法测定了其分子量。     

河南省自然灾害的地域分界规律

河南省自然灾害的地域空间分异，主要遵循水平地带性规律、非地带性规律与垂直地带性规律。水平地带性主要影响以致控制灾害的不同类型，非地带性与垂直地带性则主要影响各种灾害的成灾强度。它们相互联系与制约，从而形成该省域灾害的三维分异。     

江苏省近40年洪涝灾害概况及防洪对策

本文分析了江苏省４０ａ来洪涝灾害概况及１９９１年特大洪涝受灾情况。针对江苏实际，提出了减灾对策。     

论减灾效益的显现类型与减灾心理

减灾效益的获得离不开民众的参与,而其参与意识又与减灾效益的可见度有关。减灾效益越能迅速、明确地被人们见到或预见到,人们的减灾参与意识越高。在客观现实中,减灾效益的显现时间具有各种类型,而人们主观意识中“见”到的类型却又可能有质的差异。本文划分了减灾效益的显现类型并提出与论述了与其有关的一些问题,分析了其与主观意识之间的复杂关系,以及影响人们的减灾参与心理的作用机制。进而探讨了如何通过这些关系、机制的认识与把握,效益意识引导,对减灾见效时间意识的人为控制等途径提高民众的减灾参与意识与减灾效益。     

OPTIMAL IDENTIFICATION OF MUSKINGUM ROUTING COEFFICIENTS1

Traditionally, identification of the Muskingum routing coefficients has been based on observations of the linearity of a loop formed by graphically plotting a forward and a reverse path. This graphical procedure is time-consuming and may not minimize the error of estimation. A procedure was developed to improve the drawbacks of the graphical method. This procedure calls for (a) the use of least square regression on the forward and reverse paths to determine their respective slopes, and (b) the use of statistical t-test to evaluate the hypothesis that these two slopes are equal. The computational procedure is repeated, using incremental values of the flow weighting coefficient, x. A graph of the computed t-value versus x can be constructed. The optimal value of x, as read from the graph, occurs at the minimum computed t-value. The procedure has been demonstrated superior to the graphical method for three illustrative examples, resulting in a reduction of the error squares by factors ranging from 5 to 6.     

建立我国重大事故预防控制体系之探讨

简述了我国重大工业事故发生的主要原因，提出了建立重大事故预防控制体系的建议，制定《重大事故预防和控制法》，实行重大危险源上报、登记、评价、分级监察管理，建立国家、省、市三级重大事故应急反应系统和重大危险源动态监控网络系统。