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排序方式: 共有655条查询结果,搜索用时 15 毫秒
101.
Holger Weiß Georg Teutsch Peter Fritz Birgit Daus Andreas Dahmke Peter Grathwohl Ralf Trabitzsch Bernd Feist Ralf Ruske Olaf Böhme Mario Schirmer 《Grundwasser》2001,6(3):113-122
The SAFIRA-project (remediation research in regionally contaminated aquifers) focuses on innovative in situ remediation technologies to treat complex groundwater contamination. For this purpose, a model site located in Bitterfeld, Germany, was selected. The site is heavily contaminated with aliphatic and aromatic chlorinated hydrocarbons. The goal of the project is to develop, test and optimize new technologies of reactive barriers under controlled in situ conditions in a pilot plant. In order to create the necessary basis for this model project, the hydrogeological and hydrogeochemical conditions at the selected field site were investigated and various technologies for the design of the in situ pilot plant were examinated. Small-scale laboratory studies and tests in a mobile test unit (scale 1 m) were carried out in order to test the technologies prior to their application in the field. The technologies now tested in the reactive columns at the pilot plant include physico-chemical, microbial and combined techniques. 相似文献
102.
在博洛尼亚宣言的背景下,为了在各学校之间建立一个积极的和共同的联系,欧洲建筑教育联合会将继续发挥重要作用。提出欧洲建筑教育主要的教学挑战和希望是:新的开放局面,新的见识以及所有通过机械发明的物质潜力将具有一个清晰的基础,而且从人文环境中汲取灵感。 相似文献
103.
We report a quantitative analysis of the forces acting on optically trapped single gold nanorods. Individual nanorods with diameters between 8 and 44 nm and aspect ratios between 1.7 and 5.6 were stably trapped in three dimensions using a laser wavelength exceeding their plasmon resonance wavelengths. The interaction between the electromagnetic field of an optical trap and a single gold nanorod correlated with particle polarizability, which is a function of both particle volume and aspect ratio. 相似文献
104.
Winkelmann S Schaeffter T Koehler T Eggers H Doessel O 《IEEE transactions on medical imaging》2007,26(1):68-76
In dynamic magnetic resonance imaging (MRI) studies, the motion kinetics or the contrast variability are often hard to predict, hampering an appropriate choice of the image update rate or the temporal resolution. A constant azimuthal profile spacing (111.246 degrees), based on the Golden Ratio, is investigated as optimal for image reconstruction from an arbitrary number of profiles in radial MRI. The profile order is evaluated and compared with a uniform profile distribution in terms of signal-to-noise ratio (SNR) and artifact level. The favorable characteristics of such a profile order are exemplified in two applications on healthy volunteers. First, an advanced sliding window reconstruction scheme is applied to dynamic cardiac imaging, with a reconstruction window that can be flexibly adjusted according to the extent of cardiac motion that is acceptable. Second, a contrast-enhancing k-space filter is presented that permits reconstructing an arbitrary number of images at arbitrary time points from one raw data set. The filter was utilized to depict the T1-relaxation in the brain after a single inversion prepulse. While a uniform profile distribution with a constant angle increment is optimal for a fixed and predetermined number of profiles, a profile distribution based on the Golden Ratio proved to be an appropriate solution for an arbitrary number of profiles. 相似文献
105.
Kuo J Bredthauer GR Castellucci JB von Ramm OT 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2007,54(2):313-318
Real-time, three-dimensional (RT3D) ultrasound allows video frame rate volumetric imaging. The ability to acquire full three-dimensional (3-D) image data in real-time is particularly helpful for applications such as cardiac imaging, which require visualization of complex and dynamic 3-D anatomy. Volume rendering provides a method for intuitive graphical display of the 3-D image data, but capturing the RT3D echo data and performing the necessary processing to generate a volumetric image in real time poses a significant technical challenge. We present a data capture and rendering implementation that uses off-the-shelf components to real-time volume render RT3D ultrasound images. Our approach allowed live, interactive volume rendering of RT3D ultrasound scans. 相似文献
106.
Wesolowski R Sommer A Arndt HD Koert U Reiss P Wimmers S Strauss O 《Chembiochem : a European journal of chemical biology》2007,8(5):513-520
The function of a gramicidin hybrid ion channel in living Chinese hamster ovary (CHO) cells was investigated by the patch clamp method. The synthetic ion channel 1 consists of two cyclohexyl ether amino acids that link two mini-gramicidin strands. With 1 at a concentration of 1.0 microM, an increase in the whole-cell membrane conductance was observed after 1.37 min. The conductance showed larger currents when Cs(+) was used as charge carrier than when Na(+) and K(+) were used. In single-channel recordings with Cs(+) as charge carrier, the substance showed comparable single-channel amplitudes in the membrane of living cells and artificial black lipid bilayers. In addition to functioning as a cation channel, compound 1 appeared to be a water channel. Exposure of the CHO cells to an extracellular hypoosmotic solution did not substantially change the cell volume. Extracellular hypoosmotic conditions in the presence of 1 increased the cell size to 146.5 % that of the control. Thus, the synthetic hybrid channel 1 can function as a cation channel with some Cs(+) specificity, and as a water channel in CHO cells. 相似文献
107.
Krishnamachari VV Potma EO 《Journal of the Optical Society of America. A, Optics, image science, and vision》2007,24(4):1138-1147
The coherent anti-Stokes Raman scattering (CARS) signal is calculated as a function of focal-field distributions with engineered phase jumps. We show that the focal fields in CARS microscopy can be shaped such that the signal from the bulk is suppressed in the forward detection mode. We present the field distributions that display enhanced sensitivity to vibrationally resonant object interfaces in the lateral dimension. The use of focus-engineered CARS provides a simple means to detect chemical edges against the strong background signals from the bulk. 相似文献
108.
The development of new propellant binder systems requires the thermodynamic calculation of physico‐chemical data as well as the adaption of the mechanical properties in order to achieve a reliable innerballistic profile of the resulting propellant. However, in most cases the mechanical data may not be easily predicted due to the complex interactions between the components of the binder like the resin, the curing agent or possibly plasticizers and curing catalysts. Therefore, this study focusses on the capability of the multivariate analysis on the prediction of the E‐modulus of a system comprising nitrocellulose as well as GAP, Desmodur N100 and an energetic plasticiser. Using this method, an equation has been derived which, within the regression intervall, may be used for the prediction of the E‐modulus as a function of the components mentioned above. 相似文献
109.
The development of new propellant binder systems requires the thermodynamic calculation of physico‐chemical data as well as the adaption of the mechanical properties in order to achieve a reliable innerballistic profile of the resulting propellant. Therefore, this study focuses on the mechanical properties of a binder system comprising GAP, NC as well as the energetic plasticizer DNDA and the curing agent Desmodur N100. By applying statistical methods, the mechanical properties of the binder can be predicted as a function of its composition. A macroscopic analysis of the interrelations between the E‐modulus, the ultimate tensile strength as well as the elongation at break and the specific deformation energy lead to the creation of failure master curves, which can be used as a rule of thumb criterion for the formulation of propellant binders. 相似文献
110.
Moo-Young Huh Hyun-Chul Kim Jong-Jin Park Olaf Engler 《Metals and Materials International》1999,5(5):437-443
In order to investigate the evolution of through-thickness texture gradients in various ferritic steel sheets, samples of
a deep drawing steel, a ferritic stainless steel and a low carbon steel were deformed by cold rolling with and without application
of a lubricant during the deformation process. The hot band texture of all samples examined showed notable through-thickness
texture gradients. The evolution of the cold rolling texture in the ferritic stainless steel and the low carbon steel in a
solution-treated state was nearly independent of the lubrication during rolling. However, in the deep drawing steel and the
as-received low carbon steel, the lubrication played an important role in the formation of the through-thickness texture gradients.
Whereas the samples rolled with lubrication showed uniform textures throughout the sheet thickness, in the samples rolled
without lubrication pronounced shear textures were observed on the sheet surface. The evolution of these through-thickness
texture gradients is discussed in terms of inhomogeneous strain states computed by an FEM model.
This article is based on a presentation made in the symposium “ ’99 International Symposium on Textures of Materials”, held
at Sunchun National University, Sunchun, April 21–22, 1999 under the auspices of The Korean Institute of Metals and Materials
and The Research and Development Center for Automobile’s Parts and Materials. 相似文献