A decision tree approach modelling functional group abundance in a pasture ecosystem

Decision tree, one of the data mining approaches, was used to model the relative abundance of five functional groups of plant species, namely high fertility response grasses (HFRG), low fertility tolerance grasses (LFTG), legume, moss and flatweeds in a New Zealand hill-pasture ecosystem using aboveground biomass. The model outputs were integrated with a geographic information system (GIS) to map and validate the predictions on a pasture. The decision tree models clearly revealed the interactions between the functional groups and environmental and management factors, and also indicated the relative importance of these factors in influencing the functional group abundance. Soil Olsen P was the most significant factor influencing the abundance of LFTG and moss, while soil bulk density, slope and annual P fertiliser input were the most significant factors influencing the abundance of legume, HFRG and flatweeds, respectively. Generally, slope and soil Olsen P were the two key factors underlying the patterns of abundance for these five functional groups. For the five functional groups studied, there was an overall predictive accuracy of 75%. Modelling functional group abundance simplified the investigation of the complex interrelationship between species and environment in a pasture ecosystem. The integration of the decision tree with GIS in this study provides a platform to investigate community structure and functional composition for a pasture over space, and thus can be applied as a tool in pasture management.     

过程工业安全仪表系统的等级评定

介绍了安全整体性要求级别、安全联锁系统评定的内容、安全联锁系统评定的程序以及确定安全仪表联锁系统等级的方法,并介绍了安全保护层分析在安全联锁系统评定中的应用.     

张恒东

原油管道储运行业地域辽阔、点多线长、易燃易爆，职业危害因素种类繁多，人员接触广泛，职业卫生 工作难度较大。笔者结合工作实际，就原油管道储运企业职业健康监护谈谈工作体会，     

美国化学品危害信息的传递

1970年美国颁布<职业安全卫生法>,要求企业将作业场所化学品的危害告知作业人员.为贯彻该法的要求,20世纪80年代初期,美国职业安全卫生管理局(OSHA)颁布危害信息传递标准(HCS),要求化学品生产和进口商对生产和进口的化学品进行危害评估,并要求所有企业将有害化学品的信息传递给作业人员.     

Robust magnetic laccase-mimicking nanozyme for oxidizing o-phenylenediamine and removing phenolic pollutants

In this study, we report a novel magnetic biomimetic nanozyme(Fe_3O_4@Cu/GMP(guanosine5′-monophosphate)) with high laccase-like activity, which could oxidize toxic ophenylenediamine(OPD) and remove phenolic compounds.The magnetic laccase-like nanozyme was readily obtained via complexed Cu~(2+)and GMP that grew on the surface of magnetic Fe_3O_4 nanoparticles.The prepared Fe_3O_4@Cu/GMP catalyst could be magnetically recycled for at least five cycles while still retaining above 70% activity.As a laccase mimic,Fe_3O_4@Cu/GMP had more activity and robust stability than natural laccase for the oxidization of OPD.Fe_3O_4@Cu/GMP retained about 90% residual activity at 90℃ and showed little change at pH 3–9, and the nanozyme kept its excellent activity after long-term storage.Meanwhile, Fe_3O_4@Cu/GMP had better activity for removing phenolic compounds, and the removal of naphthol was more than 95%.Consequently, the proposed Fe_3O_4@Cu/GMP nanozyme shows potential for use as a robust catalyst for applications in environmental remediation.     

In situ preparation of g-C3N4/Bi4O5I2 complex and its elevated photoactivity in Methyl Orange degradation under visible light

A graphite carbon nitride(g-C_3N_4) modified Bi_4O_5I_2 composite was successfully prepared insitu via the thermal treatment of a g-C_3N_4/Bi OI precursor at 400°C for 3 hr.The as-prepared g-C_3N_4/Bi_4O_5I_2 showed high photocatalytic performance in Methyl Orange(MO) degradation under visible light.The best sample presented a degradation rate of 0.164 min~(-1),which is 3.2 and 82 times as high as that of Bi_4O_5I_2 and g-C_3N_4,respectively.The g-C_3N_4/Bi_4O_5I_2 was characterized by X-ray powder diffractometer(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Raman,X-ray photoelectron spectroscopy(XPS),ultraviolet-visible diffuse reflectance spectra(DRS),electrochemical impedance spectroscopy(EIS) and transient photocurrent response in order to explain the enhanced photoactivity.Results indicated that the decoration with a small amount of g-C_3N_4 influenced the specific surface area only slightly.Nevertheless,the capability for absorbing visible light was improved measurably,which was beneficial to the MO degradation.On top of that,a strong interaction between g-C_3N_4 and Bi_4O_5I_2 was detected.This interplay promoted the formation of a favorable heterojunction structure and thereby enhanced the charge separation.Thus,the g-C_3N_4/Bi_4O_5I_2 composite presented greater charge separation efficiency and much better photocatalytic performance than Bi_4O_5I_2.Additionally,g-C_3N_4/Bi_4O_5I_2 also presented high stability.·O_2~-and holes were verified to be the main reactive species.     

兰炼烷基化废酸处理工艺选择

对目前四种烷基化硫酸处理工艺进行了分析比较，认为兰炼应依托现有硫酸装置，采用裂解制硫酸工艺来处理烷基化废酸。     

运用生物循环理论建立多元生物污水处理新工艺

以活性污泥法为主流工艺的现代污水处理技术,存在着工程投资大，运行费用高，管理复杂等缺点，按照生物循环基本理论要示是不完善的。多元生物污水处理是按照食物链代谢规律,运有生物循环理论，设计成微生物－植物－水生动物3个处理单元。污水中的有机物作为微生物人良料在第1单元被套氧微生物消化降解成CO2，H2O，NH^ 4,CH^-4等，除CH4作为生物能源可回收利用外，其它物质是植物的营养物质，在第2单元藻类等多种植物吸收，通过光合作用合成植物细胞，并释放氧气，在第1单元和第2单元增殖的细胞和藻类成为水生动物的食料，在第3单元被浮游动物和鱼类捕食，转化成动物蛋白，污水中的有机物在3个单元组成的生态净化系统中，被多样生物逐级利用，最终转化成植物细胞和动物蛋白，使污水得到净化，达到三级处理水平，不产生二次污 ，是一种安全的，对环境友好的污水处理新技术，在国外被誉为21世纪的新科技。该污水净化系统，按照生物循环基本理论进行工艺设计，通过生态平衡自我调控，具有工艺流程简单，投资省，运行费用低，管理简便等优点，适合我国国情，有广阔的应用前景，尤其适有于小城镇污水处理。     

Effect of long-term fertilization on soil nitrate distribution

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溢油应急处理的优化决策

提出了溢油应急处理的优化决策方法，并运用优化理论建立评价模型来对技术决策结果进行最优化处理，从而使得各港口的溢油处理设备能够得到合理的调配，同时使溢油处理的费用降低到最低程度，而溢油处理的效果最佳，为区域合作计划的制定提供了依据。