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71.
在建筑工程设计中,要作出切合实际、安全适用、技术先进、经济效益好的设计,必须用质量特性来描述工程设计文件质量,用质量控制的方法来确保设计文件的质量。从功能性、安全性、可实施性、适应性、经济性和时间性等方面论述了质量控制的内容特性。 相似文献
72.
Jürgen R. Reichenbach Marco Essig E. Mark Haacke Benjamin C. Lee Christian Przetak Werner A. Kaiser Lothar R. Schad 《Magma (New York, N.Y.)》1998,6(1):62-69
The purpose of this study was to evaluate a non-flow related magnetic resonance imaging method to visualize small veins independent of arteries in the human brain. A long TE, high-resolution 3D gradient echo MR acquisition was used to highlight venous information. The method is based on the paramagnetic property of deoxyhemoglobin and the resulting phase difference between veins and brain parenchyma at long echo times. The MR magnitude images were masked with a phase mask filter to enhance small structure visibility.. Venous information down to sub-pixel vessel diameters of several hundred microns is visible. Venous data are displayed in an angiographic manner using a minimum intensity projection algorithm. Both superficial veins and deep white matter veins are visible. The method has been successfully applied in volunteers. Preliminary results in patients with cerebral arteriovenous malformations indicate its potential in clinical applications. The proposed method is easy to implement and does not require administration of a contrast agent or application of specially designed rf pulses to highlight the veins. Rather it exploits the intrinsic magnetic properties (BOLD-effect) and the prolonged T 2* of venous blood. The method may be of diagnostic potential in the assessment of arteriovenous malformations or other vascular venous lesions. © 1998 Elsevier Science B.V. All rights reserved. 相似文献
73.
Cavallaro A Fellner F Matzel KE Stadelmaier U Rupprecht T Böwing B Hohenberger W Bautz W 《Magma (New York, N.Y.)》1998,7(3):179-183
The aim of this study was to determine whether low-field magnetic resonance (MR) imaging can safely and accurately depict
inflammatory changes in patients with anal dynamic graciloplasty, in whom high-field MR imaging is contraindicated and ultrasonography
and computed tomography are inadequate. A 0.2-T field-strength MR examination was performed in six patients with anal dynamic
graciloplasty malfunction in whom reoperation was contemplated. The following sequences were applied:T
2-weighted turbo spinecho with fat saturation,T
1-weighted conventional spin-echo, and contrastenhancedT
1-weighted conventional spin-echo with fat saturation. Results indicated that none of the patients experienced relevant discomfort,
pacemaker malfunction, or electrode dislocation with low-field MR imaging. Inflammatory pelvic changes were visualized in
four patients and atrophy of the transposed gracilis muscle in another. Surgery was thus avoided in the four, who underwent
conservative treatment for their pelvic inflammation. It was concluded that these prelininary results demonstrate the feasibility
of MR imaging with a low field strength in patients with anal dynamic graciloplasty. In such patients, in whom diagnostic
imaging had been problematic, the potential for safe and accurate visualization will be a boon to treatment planning. 相似文献
74.
Viehweg P Heinig A Lampe D Buchmann J Heywang-Köbrunner SH 《Magma (New York, N.Y.)》1998,7(3):141-152
Purpose The aim of this study was to assess the value of contrast-enhanced (c.-e.) MRI in the follow-up of patients with conservatively
treated breast cancer since detection and exclusion of malignancy may interfere significantly with posttherapeutic changes
within the treated breast.
Material and methods A total of 207 patients with a history of limited surgery and radiation therapy underwent MR imaging, 40 patients were examined
0–12 months and 167 patients were examined later than 12 months after radiotherapy. Suspicious or indeterminate findings were
suggested by clinical examination or conventional imaging in 80 studies. In 127 women, MRI was performed within breast tissue
that was difficult to assess due to scarring or dense breast tissue.
Results Recurrent carcinoma was confirmed in 27 patients by surgical biopsy. All 27 carcinomas, except for one with a slow signal
increase, demonstrated early rise of signal intensity on dynamic T1-weighted contrast enhanced images. During the first year
after therapy, the diagnostic accuracy could not be improved by additional use of c.-e. MRI. Differentiation between posttherapeutic
changes and recurrent carcinoma was frequently not possible because of strong and sometimes early and ill-circumscribed enhancement.
Later than 12 months after therapy enhancement decreased significantly, thus the false positive calls could be reduced from
49 (conventional imaging) to 12 (conventional imaging plus MRI). A total of 12 of 26 recurrences and multifocality in 4/5
cases were diagnosed by MR imaging alone at this time interval.
Conclusion In the first year after therapy, c.-e. MRI is only indicated in selected cases. The results later than 12 months emphasize
that c.-e. MRI may contribute significant additional information. It allows better distinction of posttherapeutic fibrosis
from recurrent carcinoma and proved to be able to detect recurrent disease more sensitive and at an earlier stage. 相似文献
75.
Norbert Wilke 《Magma (New York, N.Y.)》1998,6(2-3):147-147
76.
在电子文件加密系统的控制下,经过加密控制处理的电子文件通过一定的技术处理,向文件接收方发送,使接收者能够有效地阅读加密文件。本文通过对加密文件"外发"的形式,阐述加密文件"外发"的原理和方式。 相似文献
77.
We describe an implementation of a parallel document clustering scheme based on latent semantic indexing, which uses singular value decomposition. Given a set of documents, the clustering algorithm is dynamic in the sense that it automatically infers the number of clusters to be output. The parallel version has been implemented on a LAN and on a dual‐core system. Experimental evaluation of the algorithm shows an average speed‐up of 6.22 for the LAN implementation and an average speed‐up of 3.71 for the dual‐core implementation, while still maintaining a precision and recall in the range [0.85, 1]. To put these implementations in the context of information retrieval, we use the parallel clustering algorithm and develop a document similarity search system. The similarity search system shows good performance in terms of precision and recall. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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