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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
982.
N Rizzo MC Pittalis G Pilu A Perolo C Banzi A Visentin L Bovicelli 《Canadian Metallurgical Quarterly》1996,16(2):159-163
The participation of sarcoplasmic reticulum Ca2+ release channels in the activation of Ca(2+)-sensitive K+ currents (IK(Ca)) by cyclic dibutyryl GMP was investigated in smooth muscle cells from the circular layer of guinea-pig gastric fundus. All experiments were performed in the presence of 3 microM nicardipine into the bath and low Ca2+ buffering capacity of the pipette-filling solution (pCa 7.4). Ruthenium red (10 microM) as well as its combination with 10 microM heparin abolished the cyclic GMP-induced activation of IK(Ca), while 10 microM heparin remained ineffective. Ryanodine (10 microM) and the subsequently added 1 microM thapsigargin induced a relatively small increase in IK(Ca) amplitudes. The addition of 10 microM ryanodine to 1 microM thapsigargin-containing bath solution caused a vast increase in IK(Ca). It is hypothesyzed that protein kinase G-induced vectorial Ca2+ flux from the cell bulk and sarcoplasmic reticulum Ca2+ stores toward the plasma membrane is realized by a spontaneous Ca(2+)-induced Ca2+ release from a superficially situated Ca2+ store. 相似文献
983.
Neusser S. Nijhuis J. Spaanenburg L. Hoefflinger B. Franke U. Fritz H. 《Micro, IEEE》1993,13(1):57-66
A solution to autonomous lateral vehicle guidance using a neurocontroller that can learn from measured human-driving data without knowledge of the physical car parameters is discussed. Simulations and practical tests confirm that a small-size feedforward autonomous neural network (21 neurons) can learn to steer a vehicle at high speeds only from looking at human-driving examples. In this way, the network learns the total closed-loop behavior, including the nonlinear dynamics of the vehicle and the driver's individual driving style. The main result of practical investigations is that the neutral controller trained on human-driving examples exhibits an aperiodic behavior that does not vanish at higher speeds (tests performed up to 130 km/h) and produces fewer lateral deviations than the linear state controller 相似文献
984.
Following two years operation of the 100 kW grid-connected installation N13 near Domat/Ems, Switzerland, considerable data are available. The yield of the installation was calculated on the basis of long-term meteorological data and of the Meteonorm model. The findings show a close correlation between the forecast and the measured yields. With 100% availability of the inverter in 1991, the performance of the installation rose from 59% in 1990 to 79% in 1991. With standardized analysis of the data, the performance of the grid-connected installation N13 can be compared with other grid-connected installations irrespective of size and location. 相似文献
985.
Dennis L. Nielson 《Geothermics》1996,25(4-5)
The exploration for a geothermal resource on Ascension Island utilized a strategy that initially employed geologic mapping. On the basis of this, subsurface faults were mapped using an aeromagnetic survey. The faults were then explored using electrical resistivity surveys to define areas of potential hydrothermal fluid up-welling. The results of all of these techniques were used to site temperature gradient holes. A deep geothermal exploration well was then drilled in the area with highest heat flow adjacent to a rhyolite-to-trachyte volcanic complex. 相似文献
986.
Experiments conducted at ground stations of the Quasar satellite communication network using both a null base as well as a
base of around 2000 km is described. In experiments with a null base, the time scale transmission error was 1 nsec. Comparison
of the results of collocation with data cbtained by the GLONASS system in the course of experiments using a 2100-km base demonstrated
a divergence of the results of from 5 to 25 nsec.
Translated from Izmeritel'naya Tekhnika, No. 4, pp. 35–38, April, 1996. 相似文献
987.
Gonzalez A. Valero-Garcia M. Diaz de Cerio L. 《Parallel and Distributed Systems, IEEE Transactions on》1995,6(8):803-814
Many parallel algorithms use hypercubes as the communication topology among their processes. When such algorithms are executed on hypercube multicomputers the communication cost is kept minimum since processes can be allocated to processors in such a way that only communication between neighbor processors is required. However, the scalability of hypercube multicomputers is constrained by the fact that the interconnection cost-per-node increases with the total number of nodes. From scalability point of view, meshes and toruses are more interesting classes of interconnection topologies. This paper focuses on the execution of algorithms with hypercube communication topology on multicomputers with mesh or torus interconnection topologies. The proposed approach is based on looking at different embeddings of hypercube graphs onto mesh or torus graphs. The paper concentrates on toruses since an already known embedding, which is called standard embedding, is optimal for meshes. In this paper, an embedding of hypercubes onto toruses of any given dimension is proposed. This novel embedding is called xor embedding. The paper presents a set of performance figures for both the standard and the xor embeddings and shows that the latter outperforms the former for any torus. In addition, it is proven that for a one-dimensional torus (a ring) the xor embedding is optimal in the sense that it minimizes the execution time of a class of parallel algorithms with hypercube topology. This class of algorithms is frequently found in real applications, such as FFT and some class of sorting algorithms 相似文献
988.
Single-assignment and functional languages have value semantics that do not permit side-effects. This lack of side-effects makes automatic detection of parallelism and optimization for data locality in programs much easier. However, the same property poses a challenge in implementing these languages efficiently. This paper describes an optimizing compiler system that solves the key problem of aggregate copy elimination. The methods developed rely exclusively on compile-time algorithms, including interprocedural analysis, that are applied to an intermediate data flow representation. By dividing the problem into update-in-place and build-in-place analysis, a small set of relatively simple techniques—edge substitution, graph pattern matching, substructure sharing and substructure targeting—was found to be very powerful. If combined properly and implemented carefully, the algorithms eliminate unnecessary copy operations to a very high degree. No run-time overhead is imposed on the compiled programs. 相似文献
989.
Myers Jerome L.; O'Brien Edward J.; Albrecht Jason E.; Mason Robert A. 《Canadian Metallurgical Quarterly》1994,20(4):876
Previous research demonstrated a contradiction effect: Although text currently being processed was locally coherent, readers were aware of inconsistencies between a protagonist's actions and characteristics of the protagonists that were described earlier in the text and subsequently backgrounded. In the present experiments, not only the critical characteristics but also the protagonist were backgrounded. When the protagonist was reintroduced into the narrative in the context of carrying out an inconsistent action, the contradiction effect again occurred. In Exps 1–3, we examined the effects of several variables on the onset of the effect. In Exp 4, we presented probes at various points in the passage with results that supported the conclusion that the critical characteristics had been backgrounded before the sentence that contradicted them. Results are discussed in terms of several recent models in which currently active representational elements serve as retrieval cues for other inactive, but highly related, elements. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
990.
Methods are described for forming coating specimens and testing them in pure bending. The proposed tester gives adequate accuracy in determining the elastic characteristics and strength for thin specimens (up to 0.1 mm) of brittle materials of powder-coating type.Translated from Problemy Prochnosti, No. 3, pp. 94–97, March, 1993. 相似文献