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701.
702.
Becker E. W. Bier W. Ehrfeld W. Schubert K. Schütte R. Seidel D. 《Die Naturwissenschaften》1976,63(9):407-411
The Science of Nature - The development of reliable manufacturing methods for commercial separation elements, the successful operation of separative stages, and extensive tests performed on plant... 相似文献
703.
J. Altenburger Th. Dielacher P. Eder H. Ferner M. Fegerl J. Fresner O. Gelinek A. Kogler J. Jantschgi M. Nussbaumer B. Russegger H. Schnitzer K. Schauer B. Sebesta J. Seiler F. Sprenger H. Widenmeyer 《Journal of Cleaner Production》1994,2(3-4)
The paper focuses upon the organization of a federal state-funded pollution prevention project in the Styrian industry. The project includes 13 companies from the textile, pulp and paper, machine building, wood working and printed circuit board manufacturing industries, covering most of the sectors and sizes in the Styrian industry. It started in January 1994 and will last for one year. It will demonstrate the possibilities of pollution prevention and the need for further research work. This project will make use of the methods and tools that were refined in the Austrian Prepare project. As a first step, a systematic balance of all the inputs and outputs of a company is made, after which the weak points and inefficiencies of material and energy use are identified and the options for improvements, both economical and ecological, are defined. Consequently, modifications in products and production lead to a situation with less waste and emissions. The preliminary lessons from these projects are presented: as a rule, the utilities (consumption of process materials and water, cleaning, energy, preparatory and finishing steps) are treated as black boxes and usually represent a considerable optimization potential. In these areas especially there is usually a lack of information and coordination as well as a need for a systematic and comprehensive approach. Leadership in the company and creative consultants are needed for starting lasting successful pollution prevention projects. 相似文献
704.
ZHANG Jian-ying QIU Li-min HE Jia LIAO Yuan LUO Yong-ming College of Environmental Resource Sciences Zhejiang University Hangzhou China. Soil Environment Bioremediation Research Center Institute of Soil Science Chinese Academy of Sciences Nanjing China 《环境科学学报(英文版)》2007,(3)
A total of 198 agricultural soil samples were collected from Zhangjiagang and Changshu in Southern Jiangsu for analysis of 13 polychlorinated biphenyls (PCBs) in order to assess the levels of pollution, sources, area distribution, and potential risk for the environment. All methods were rigorously tested and an adequate quality control was ensured. Only one site had no PCBs residues, and the highest total PCBs concentration in the surface soils was 32.83 ng/g. The average concentration in all the soil samples was 4.13 ng/g, signaling low-level pollution. Tetra-, penta-, and hexa-chlorinated biphenyls were dominant species in soil samples, accounting for more than 75% ofΣPCBs in the soil samples. PCB118 was the most abundant congener in all the samples. The PCB118 was about 20% ofΣPCBs. The soil organic matter content showed only a weak correlation with the levels of all PCB congeners, in which a better correlation was noted for the more volatile lighter PCB congeners than for the heavier homologues. To a certain extent, the sources and land use seemed to influence the levels of PCBs. 相似文献
705.
706.
The modern theory of biological evolution: an expanded synthesis 总被引:12,自引:2,他引:12
In 1858, two naturalists, Charles Darwin and Alfred Russel Wallace, independently proposed natural selection as the basic mechanism responsible for the origin of new phenotypic variants and, ultimately, new species. A large body of evidence for this hypothesis was published in Darwins Origin of Species one year later, the appearance of which provoked other leading scientists like August Weismann to adopt and amplify Darwins perspective. Weismanns neo-Darwinian theory of evolution was further elaborated, most notably in a series of books by Theodosius Dobzhansky, Ernst Mayr, Julian Huxley and others. In this article we first summarize the history of life on Earth and provide recent evidence demonstrating that Darwins dilemma (the apparent missing Precambrian record of life) has been resolved. Next, the historical development and structure of the modern synthesis is described within the context of the following topics: paleobiology and rates of evolution, mass extinctions and species selection, macroevolution and punctuated equilibrium, sexual reproduction and recombination, sexual selection and altruism, endosymbiosis and eukaryotic cell evolution, evolutionary developmental biology, phenotypic plasticity, epigenetic inheritance and molecular evolution, experimental bacterial evolution, and computer simulations (in silico evolution of digital organisms). In addition, we discuss the expansion of the modern synthesis, embracing all branches of scientific disciplines. It is concluded that the basic tenets of the synthetic theory have survived, but in modified form. These sub-theories require continued elaboration, particularly in light of molecular biology, to answer open-ended questions concerning the mechanisms of evolution in all five kingdoms of life.Dedicated to Prof. Dr. Dr. hc mult. Ernst Mayr on the occasion of his 100th birthdayThis revised version was published online in March 2004, with corrections to the caption of Figure 6. 相似文献
707.
A. Raman 《Die Naturwissenschaften》1967,54(21):560-560
708.
709.
Bernd P. Maier 《Die Naturwissenschaften》1977,64(2):59-68
The 57-MW high-flux reactor of the Institute Max von Laue-Paul Langevin at Grenoble serves as a central neutron-beam facility for laboratories and research institutes in the three member countries, the United Kingdom, France, and the Federal Republic of Germany. The heavy-water-moderated and -cooled reactor is equipped with hot, thermal, and cold moderators, providing neutrons with high intensity over an unusual wide range of energies (wavelengths) extending from some 0.1 meV (30 Å) up to some 500 meV (0.4 Å). An extensive system of neutron guides with different curvatures permits the transport of neutrons over distances ranging up to 140 m with minimal intensity losses for neutrons in the useful wavelength band. The transmitted beams, in addition, exhibit very low background contamination by fast and epithermal neutrons, and γ-radiation. A large variety of high-resolution neutron spectrometers provide unique opportunities in fields such as nuclear physics, crystallography, solid-state physics, chemistry, metallurgy, and biology. 相似文献
710.
C. K. Jørgensen 《Die Naturwissenschaften》1980,67(4):188-189