超大型金属矿床研究现状和某些进展

介绍了近年来超大型金属矿床理论研究现状,探讨了超大型铜、铅、锌、金和铂族等有色贵金属矿床的成矿构造背景,认为该类超大型矿床产出的主要全球构造背景为板块俯冲带和大陆裂谷,并论述了不同构造背景中超大型矿床的成因类型、矿床特征、控矿构造和矿床空间展布规律以及裂谷构造垂向分带和不同地史时期裂谷与超大型矿床的关系,对当前研究工作中一些问题进行了讨论。     

On paleoecology of carnivorous dinosaurs(Tyrannosauridae,Dromaeosauridae) from Late Cretaceous fossil deposits of Amur region,Russian Far East

Present article is on Russian Far East carnivorous dinosaur paleoecology.Described summary is based on detailed study and comparison of isolated shed teeth morphology.     

On paleoecology of carnivorous dinosaurs ( Tyrannosauridae，Dromaeosauridae) from Late Cretaceous fossil deposits of Amur region，Russian Far East

Present article is on Russian Far East carnivorous dinosaur paleoecology． Described summary is based on detailed study and comparison of isolated shed teeth morphology．     

Cometary Physics

Unpredicted apparitions of bright comets appearing on the night sky for a few months movingfast among the stars have intrigued mankind whenever the sky was observed. Records ofcomets are found in the oldest documents and can be still useful as demonstrated during the as-sessment of the non-gravitational forces acting on comet Halley(Yeomans and Kiang, 1981).chinese records with relatively precise positions from more than 2000 years ago gave important     

THE ROLE OF RAILROAD IN THE DEVELOPMENT OF THE AMERICAN WEST—Railroad,Migration and Urban Growth

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THE EFFECT OF MISLABELED SAMPLES ON THE PERFORMANCE OF THE LINEAR LEARNING MACHINE

Over the past 15 years the linear learning machine has been applied to a large number of chemicalproblems.The learning machine approach is conceptually simple and does not require knowledge aboutthe statistical distribution of the data.However,there are problems associated with this approach.Oneproblem which has not been investigated is the influence of mislabeled samples on the positioning of thehyerplane in feature space.If a few samples in a data set are incorrectly tagged prior to training(i.e.thesamples are labeled as members of class 2 even though they are actually members of class 1),it is stilIpossible using the linear learning machine to achieve a classification success rate of 100% for the trainingset.However,unfavorable results will be obtained for the prediction set.The magnitude of this effect andits potential implications regarding the proper use of the linear learning machine are discussed.     

Field methods for amending marine sediment with activated carbon and assessing treatment effectiveness

Previous laboratory studies have shown reductions in PCB bioavailability for sediments amended with activated carbon (AC). Here we report results on a preliminary pilot-scale study to assess challenges in scaling-up for field deployment and monitoring. The goals of the preliminary pilot-scale study at Hunters Point Shipyard (San Francisco, USA) were to (1) test the capabilities of a large-scale mixing device for incorporating AC into sediment, (2) develop and evaluate our field assessment techniques, and (3) compare reductions in PCB bioavailability found in the laboratory with well-mixed systems to those observed in the field with one-time-mixed systems. In this study we successfully used a large-scale device to mix 500kg of AC into a 34.4m(2) plot to a depth of 1ft, a depth that includes the majority of the biologically active zone. Our results indicate that after 7 months of AC-sediment contact in the field, the 28-day PCB bioaccumulation for the bent-nosed clam, Macoma nasuta, field-deployed to this AC-amended sediment was approximately half of the bioaccumulation resulting from exposure to untreated sediment. Similar PCB bioaccumulation reductions were found in laboratory bioassays conducted on both the bivalve, M. nasuta and the estuarine amphipod, Leptocheirus plumulosus, using sediment collected from the treated and untreated field plots one year after the AC amendment occurred. To further understand the long-term effectiveness of AC as an in situ treatment strategy for PCB-contaminated sediments under field conditions, a 3-year comprehensive study is currently underway at Hunters Point that will compare the effectiveness of two large-scale mixing devices and include both unmixed and mixed-only control plots.     

Discussion on “Hydraulic parameters in channels with wall vegetation and gravel bed” by Hossein Afzalimehr, Jueyi Sui and Razieh Moghbel [Int. J. Sed. Res., 25 (2010) 81–90]

We discussants appreciate the authors’ investigation on the impacts of the vegetated channel walls and aspect ratio on flow velocity profiles,shear stress distribution and roughness coefficient of channel.The primary aim of this comment is to emphasize some of the points which were not considered by the authors during their study.The discussers would like to mention the following points regarding the paper. The expression of "wall vegetation" is a new term for the current literature.However the researchers have not given enough explanation about wall-vegetation.What is "wall vegetation"?Where can we observe wall-vegetation in nature?What are the characteristic species as "wall-vegetation"?We think that the clarification of this point will significantly improve the benefit of this study.