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排序方式: 共有244条查询结果,搜索用时 94 毫秒
111.
Priority pollutants in surface waters and settleable particles within a densely urbanised area: Case study of Paris (France) 总被引:1,自引:0,他引:1
Johnny Gasperi Stéphane Garnaud Régis Moilleron 《The Science of the total environment》2009,407(8):2900-2908
Implementation of the European Water Framework Directive 2000/60/EC (WFD) requires Member States to expand their collective knowledge of priority pollutants (PPs) within receiving waters. To achieve this objective, information on the occurrence of PPs in surface waters and, more specifically, within densely urbanised areas needs to be collected. This study has therefore been designed to provide information on both PP occurrence and concentration build-up along a heavily urbanised transect of the Seine River in the Paris region (France). A large range of PPs were observed in settleable particles and, to a lesser extent, in the waters surveyed. In surface waters, a total of 18 PPs, including 15 priority hazardous substances?, were indeed detected, yet concentrations rarely exceeded the limit of quantification. In fact, only diuron?, DEHP?, fluoranthene and para-tert-octylphenol? are observed on a frequent basis, with concentrations ranging from < 0.01 to 1.0 µg l− 1. As regards the Environmental Quality Standards (EQS), 10 substances or groups of substances were found in surface waters to exhibit concentrations above the annual average value, while only the benzo(a)pyrene? concentration exceed the maximum allowable level. As for the Canadian Sediment Quality Guidelines, settleable particles collected in the Seine River appear to be heavily contaminated since most samples contain PP levels above the guideline values (18 PPs) and, in many cases, above the probable effect levels (15 PPs), which underscores that the levels of metals, PAHs and PCBs in settleable particles constitute a potential risk to freshwater organisms. 相似文献
112.
Wetter Martha W.; Baer Ruth A.; Berry David T. R.; Robison Lori H.; Sumpter Johnny 《Canadian Metallurgical Quarterly》1993,5(3):317
Two groups of normal adults were given specific symptom information on posttraumatic stress disorder (PTSD) and paranoid schizophrenia, respectively, and instructed to simulate these disorders on the MMPI-2. Monetary prizes were offered for successful faking. To determine whether symptom information helped Ss produce responses that closely resembled patients' profiles, scores from fakers were compared with scores from patients with these disorders, using a 2?×?2 (Disorder?×?Response Style) ANOVA. Results showed significant differences for response style, with fakers in both groups producing lower scores on K and higher scores on F, Fb, F–K, Ds, as well as on all 10 clinical scales, than patients. The findings suggest that having specific information about the symptoms of psychological disorder does not enable fakers to avoid detection and/or produce profiles equivalent to those produced by patients with the disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
113.
The electrical properties of micrometre-sized inversion-layer (IL) emitters in crystalline Si are investigated by measuring their current–voltage characteristics using a so-called NOSFET device. The IL emitter is induced by a SiN/SiO double-layer stack. We show that by scanning the surface with a negatively biased tip, the IL emitter below the tip can be controllably eliminated. 相似文献
114.
Rosmary N. Brandalise Mara Zeni Johnny D. N. Martins Maria M.C. Forte 《Polymer Bulletin》2009,62(1):33-43
Summary Blends of post-consumer high density polyethylene (HDPEr) and poly(vinyl alcohol) (PVA) were prepared with maleic anhydride-grafted
HDPEr (HDPEr-AM), as the compatibilizer, to evaluate the effectiveness of the PVA as a modifier for polyethylene and influence
of PVA concentration on the blend properties. Films of polyethylene having biodegradable polymers could be a good solution
for agricultural purpose since they can degrade more easily. The blends HDPEr/HDPEr-AM/PVA were investigated by physical tests,
dynamic-mechanical analysis (DMA) and scanning electron microscopy (SEM). Thermal properties were measured by means of differential
scanning calorimetry (DSC). The blend HDPEr/HDPEr-AM/PVA (50/10/40) with 10wt% of compatibilizer showed the highest tensile
strength (28 MPa) compared to the blends (60/40) without compatibilizer (11 MPa). On the other hand, morphologic analysis
showed synergism of the polymers in the blend HDPEr/HDPEr-AM/PVA (30/10/60), with 10wt% of compatibilizer. Overall, it was
observed that the blend HDPEr/HDPEr-AM/PVA with composition of (70/10/20) showed the best properties for agricultural films
processing application. 相似文献
115.
Johnny Andrew Normaz Wana Ismail Marcel Djama 《Journal of the science of food and agriculture》2018,98(1):12-17
The application of agricultural biotechnology attracts the interest of many stakeholders. Genetically modified (GM) crops, for example, have been rapidly increasing in production for the last 20 years. Despite their known benefits, GM crops also pose many concerns not only to human and animal health but also to the environment. Malaysia, in general, allows the use of GM technology applications but it has to come with precautionary and safety measures consistent with the international obligations and domestic legal frameworks. This paper provides an overview of GM crop technology from international and national context and explores the governance and issues surrounding this technology application in Malaysia. Basically, GM research activities in Malaysia are still at an early stage of research and development and most of the GM crops approved for release are limited for food, feed and processing purposes. Even though Malaysia has not planted any GM crops commercially, actions toward such a direction seem promising. Several issues concerning GM crops as discussed in this paper will become more complex as the number of GM crops and varieties commercialised globally increase and Malaysia starts to plant GM crops. © 2017 Society of Chemical Industry 相似文献
116.
117.
Tennyson Robert D.; Chao Johnny N.; Youngers Judith 《Canadian Metallurgical Quarterly》1981,73(3):326
Investigated whether concept learning is a 2-fold process: acquisition of a prototype and development of generalization and discrimination skills. Data analyses showed that learning was facilitated for 120 4th-grade students by a presentation form that combined expository statements of best examples (prototype acquisition) with interrogatives (skill development) over presentations that were expository or interrogatory only. At the concrete and identity levels of concept attainment, a prototype was learned with all 3 presentation forms, but only with the expository–interrogatory form was the acquired prototype maintained on the retention test. At the classificatory and formal levels, skills were developed and maintained with the expository-interrogatory presentation form only. A 2nd independent variable contrasted instructional materials designed with and without formative evaluations. Results show no difference in posttest performance. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
118.
A Software Fault Tree Approach to Requirements Analysis of an Intrusion Detection System 总被引:2,自引:0,他引:2
Guy Helmer Johnny Wong Mark Slagell Vasant Honavar Les Miller Robyn Lutz 《Requirements Engineering》2002,7(4):207-220
Requirements analysis for an intrusion detection system (IDS) involves deriving requirements for the IDS from analysis of
the intrusion domain. When the IDS is, as here, a collection of mobile agents that detect, classify, and correlate system
and network activities, the derived requirements include what activities the agent software should monitor, what intrusion
characteristics the agents should correlate, where the IDS agents should be placed to feasibly detect the intrusions, and
what countermeasures the software should initiate. This paper describes the use of software fault trees for requirements identification
and analysis in an IDS. Intrusions are divided into seven stages (following Ruiu), and a fault subtree is developed to model
each of the seven stages (reconnaissance, penetration, etc.). Two examples are provided. This approach was found to support
requirements evolution (as new intrusions were identified), incremental development of the IDS, and prioritisation of countermeasures.
Correspondence and offprint requests to: G. Helmer, Department of Computer Science, 226 Atanasoff Hall, Iowa State University, Ames, Iowa 50011, USA. Email: ghelmer@cs.iastate.edu 相似文献
119.
Air pollution problems in three different tropical areas are presented. The levels of various atmospheric contaminants (i.e. SO4=) indicate that the operation of a large petroleum refinery affects a substantial portion of the island of Curacao. A significant fraction of the suspended particles in Curacao are due to non-traditional open source emissions aided by the predominantly high wind speeds. Particulate emissions from the industrial complex in Guayana, Venezuela, noticeably affect the surrounding savannah. The constant direction of the Trade Winds is an important factor in the high long-term average particulate levels down-wind of the complex. A serious atmospheric contamination problem (i.e. TSP) exists in The Valley of Caracas. The high emission, principally due to the circulation of vehicles, exceed the average dispersion capacity of the atmosphere. 相似文献
120.
A generic approach for deploying various types of synthetic nanomaterials, including single-walled carbon nanotubes and nanoparticles, at well-defined locations on substrates is presented. The assembly is achieved through the complementary design of the stationary and carrier phases and utilizes the dewetting process during which polymer-encapsulated nanomaterials are delivered and positioned on predefined locations of substrates. Covalent modification of the nano-objects is not required for the building block positioning, therefore, preserving their intrinsic chemical and physical properties. The potency of this new approach is demonstrated for various synthetic nanomaterials, such as polystyrene, silica, and gold nanoparticles as well as single-walled carbon nanotubes, showing highly specific and direct patterning of cm2 areas using a generic assembly strategy. 相似文献