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2018年第2期(发布时间: Jun 25, 2018 发布者:王阳)  下载: 2018年第2期.doc       全选  导出
1   2018-06-25 10:45:17.343 美国环保署大湖区国家计划办公室的水质调查简史 (点击量:2)

The U.S. Environmental Protection Agency Great Lakes National Program Office (GLNPO) water quality survey (WQS) constitutes the longest-running, most extensive monitoring of water quality and the lower trophic level biota of the Laurentian Great Lakes, and has been instrumental in tracking shifts in nutrients and the lower food web over the past several decades. The initial impetus for regular monitoring of the Great Lakes was provided by the 1972 Great Lakes Water Quality Agreement (GLWQA) which asked the parties to develop monitoring and surveillance programs to ensure compliance with the goals of the agreement. The resulting monitoring plan, eventually known as the Great Lakes International Surveillance Plan (GLISP), envisioned a nine-year rotation of intensive surveys of the five lakes. A broadening of the scope of the GLWQA in 1978 and the completion of the first nine-year cycle of sampling, prompted reappraisals of the GLISP. During this pause, and using knowledge gained from GLISP, GLNPO initiated an annual WQS with the narrower focus of tracking water quality changes and plankton communities in the offshore waters of the lakes. Beginning in 1983 with lakes Erie, Huron, and Michigan, the WQS added Lake Ontario in 1986 and Lake Superior in 1992, evolving into its current form in which all five lakes are sampled twice a year. The WQS is unique in that all five lakes are sampled by one agency, using one vessel and one principal laboratory for each parameter group, and represents an invaluable resource for managing and understanding the Great Lakes.

2   2018-06-25 10:45:53.27 研究表明更可靠的碳基微电子技术可解决水问题 (点击量:0)

Research Charts the Way to More Reliable Carbon-based Microelectronics.
Details]Satish Kumar, an associate professor in the George W. Woodruff School of Mechanical Engineering, and Jialuo Chen, a graduate student at Georgia Tech.
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Posted June 14, 2018 • Atlanta, GA
Carbon nanotubes – cylindrical formations of carbon atoms with incredible strength and electrical conductivity – hold great promise for creating new micron-scale low-power electronic devices.
But finding a way to build a reliable computing platform based on the carbon material has been a major challenge for researchers.
Now, a team of mechanical and materials engineers at Georgia Institute of Technology has devised a method for identifying performance variabilities in transistors made from carbon nanotube networks. The new approach could help researchers create more reliable devices and ultimately harness that technology for a range of applications such as wearable electronics, sensors and antennas.
“Using carbon nanotubes to make thin-film transistors with good performance repeatability has been challenging because of the random imperfections in the fabrication process,” said Satish Kumar, an associate professor in the George W. Woodruff School of Mechanical Engineering. “Those random imperfections cause variations in the properties of the nanotubes – differences in length, diameter and chirality. All of those things can impact how conductive a nanotube is, which leads to these performance variations.
“What we’ve done now is created a systematic way to estimate these variations that could improve reliability for carbon nanotube network based devices,” he said.
Results from the study, which was sponsored by the National Science Foundation, were published in March in IEEE Transactions on Nanotechnology.
While earlier research has looked at how to improve production methods for carbon nanotubes in order to achieve more uniformity, Kumar’s team focused on analyzing performance variabilities in statistical way so that performance characteristics could be more estimable.
“Such analysis is crucial to explore the reliability and stability of carbon nanotube network based circuits and to devise techniques which can help reduce variability in circuit performance for various electronic applications,” Kumar wrote with in the paper with Jialuo Chen, a graduate student at Georgia Tech.
While some carbon nanotubes conduct electricity much in the same way that a semiconductor such as silicon, certain carbon nanotubes have conductivity properties more similar to metal. The latter types are called metallic carbon nanotubes. The prevalence of such metallic carbon nanotubes in a network is linked to performance problems.
The study found that the metallic-property carbon nanotubes caused performance variations more so in thin-film transistors with short channels than those with long channels, which means device designers could achieve higher performance by using networks that have a higher concentration of long channel thin-film transistors.
The researchers also found that variations in length of the carbon nanotubes seemed to have less impact on performance as long as the network of nanotubes was dense.
“Our results show that the performance variability of thin-film transistors can be reconstructed using the distribution function of relevant parameters which will help us to create more reliable  circuits to enable the next generation of low-cost flexible microelectronics,” Kumar said.
This material is based upon work supported by the National Science Foundation under Grant No. CCF-1319935. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.
CITATION: Jialuo Chen and Satish Kumar, “Variability in Output Characteristics of Single-Walled Carbon Nanotube Thin-Film Transistors,” (IEEE Transactions on Nanotechnology (March 2018). http://dx.doi.org/10.1109/TNANO.2018.2803106
DetailsA close up view of thin-film transistors formed from networks of carbon nanotubes.
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Contact Information.
Josh Brown
Research News
(404) 385-0500
Email: josh.brown@comm.gatech.edu
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Electronics and Nanotechnology.
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3   2018-06-25 10:46:22.567 美国环保局将主办大湖区恢复倡议计划三罗彻斯特公众参与会议 (点击量:0)

EPA to Host Great Lakes Restoration Initiative Plan III Public Engagement Session in Rochester.
06/12/2018
Contact Information:  Francisco Arcaute (arcaute.francisco@epa.gov) 312-886-7613 312-898-2042 Cell
For Immediate Release    No. 18-OPA25
CHICAGO (June 12, 2018) – U.S. Environmental Protection Agency (EPA) will host the second of six informal public engagement sessions on the Great Lakes Restoration Initiative Action Plan III next week in Rochester, N.Y. The session will run from 6-8 p.m. on Thursday, June 21, at the Roger Robach Community Center, 180 Beach Ave.
What
GLRI Plan III Public Engagement Session
When
Thursday, June 21 6:00 – 8:00 p.m.
Where
Roger Robach Community Center 180 Beach Ave.
 
At the June 21 engagement session, members of the public will be able to learn more about the GLRI Action Plan development process, talk with representatives from EPA and other agencies, and provide input on priorities to be used in the initial stage of developing a GLRI Action Plan covering fiscal years 2020 through 2024.
Meetings in Duluth, Minn.; Milwaukee, Wis.; Saginaw, Mich.; and Chicago, Ill., will follow later this summer.
Background
EPA and its federal partners are currently developing Action Plan III, which will outline GLRI priorities and goals for 2020-2024. Its focus will be on:  
Toxic substances and areas of concern;.
Invasive species;.
Nonpoint source pollution impacts on nearshore health;.
Habitat and species; and.
Future actions.
The proposed plan is expected to be available for formal public comment this fall.
For more information on GLRI and Action Plan III, visit: https://www.glri.us/

4   2018-06-25 10:47:54.077 美国环保局将在托莱多举办第一次大湖区恢复倡议计划III公众参与会议| 美国环保署 (点击量:0)

News Releases from Region 05 .
EPA to Host First Great Lakes Restoration Initiative Plan III Public Engagement Session in Toledo .
06/07/2018
Contact Information:  Francisco Arcaute (arcaute.francisco@epa.gov) 312-886-7613 312-898-2042 Cell
For Immediate Release    No. 18-OPA19
EPA to Host First Great Lakes Restoration Initiative Plan III Public Engagement Session in Toledo
CHICAGO (June 7, 2018) – U.S. Environmental Protection Agency (EPA) will host the first of six informal public engagement sessions on the Great Lakes Restoration Initiative Action Plan III next week in Toledo. The session will run from 6-8 p.m. on Wednesday, June 13, at the University of Toledo Law Auditorium at 1825 West Rocket Drive.
What
GLRI Plan III Public Engagement Session
When
Wednesday, June 13 6:00 – 8:00 p.m.
Where
University of Toledo Law Auditorium 1825 West Rocket Drive
At the June 13 engagement session, members of the public will be able to learn more about the GLRI Action Plan development process, talk with representatives from EPA and other agencies, and provide input on priorities to be used in the initial stage of developing a GLRI Action Plan covering fiscal years 2020 through 2024.
 
Meetings in Rochester, N.Y.; Duluth, Minn.; Milwaukee; Saginaw, Mich.; and Chicago will follow later this summer.
Background
EPA and its federal partners are currently developing Action Plan III, which will outline GLRI priorities and goals for 2020-2024. Its focus will be on:  
Toxic substances and areas of concern;.
Invasive species;.
Nonpoint source pollution impacts on nearshore health;.
Habitat and species; and.
Future actions.
The proposed plan is expected to be available for formal public comment this fall.
For more information on GLRI and Action Plan III, visit: https://www.glri.us/

5   2018-06-25 10:47:05.78 美国环境保护署大湖区国家计划办公室对劳伦琴大湖区的监测:从40年的数据收集的洞察力 (点击量:0)

The U.S. EPA Great Lakes National Program Office (GLNPO) implements long-term monitoring programs to assess Great Lakes ecosystem status and trends for many interrelated ecosystem components, including offshore water quality as well as offshore phytoplankton, zooplankton and benthos; chemical contaminants in air, sediments, and predator fish; hypoxia in Lake Erie's central basin; and coastal wetland health. These programs are conducted in fulfillment of Clean Water Act mandates and Great Lakes Water Quality Agreement commitments. This special issue presents findings from GLNPO's Great Lakes Biology Monitoring Program, Great Lakes Water Quality Monitoring Program, Lake Erie Dissolved Oxygen Monitoring Program, Integrated Atmospheric Deposition Network, Great Lakes Fish Monitoring and Surveillance Program, and Great Lakes Sediment Surveillance Program. These GLNPO programs have generated temporal and spatial datasets for all five Great Lakes that form the basis for assessment of the state of these lakes, including trends in nutrients, key biological indicators, and contaminants in air, sediments and fish. These datasets are used by researchers and managers across the Great Lakes basin for investigating physical, chemical and biological drivers of ongoing ecosystem changes; some of these analyses are presented in this special issue, along with discussion of new methods and approaches for monitoring.

6   2018-06-25 10:47:28.947 利用卫星观测来评估GLNPO水质监测计划的空间代表性 (点击量:1)

The U.S. EPA's Great Lakes National Program Office (GLNPO) annual water quality survey (WQS) collects data at a relatively small number of stations in each lake. The survey was designed to measure conditions in the open-water regions of the lakes where an assumption of spatial homogeneity was thought likely to be met and the measured variables could be characterized by simple statistics. Here we use satellite observations to assess how well statistics based on samples collected in the GLNPO sampling network represent the lake-wide values of two variables, surface chlorophyll concentration and Secchi depth. We find strong linear relationships between the mean values calculated from the samples and the corresponding averages based on the subsets of the full satellite images. Although overall the means of the values from the sample locations agree well with means calculated from most of the non-coastal regions of the lakes, in terms of water depth, the GLNPO station averages best represent the regions of Lake Huron deeper than 30?m, of Lakes Michigan and Superior deeper than 90?m, and of Lake Ontario deeper than 60?m. When the lake regions are defined by distance offshore rather than by depth, the GLNPO station chlorophyll means in Lakes Huron, Ontario, and Superior are closest to the means for the area of the lakes >10?km offshore. In Lake Michigan the closest correspondence is with the >20?km offshore region. On a whole-lake basis in Lake Erie the GLNPO station chlorophyll averages are closest to the average calculated from the entire lake.