To gain insight into the inelastic behavior of piles, the response of a vertical pile embedded in dry sand and subjected to cyclic lateral loading was studied experimentally in centrifuge tests conducted in Laboratoir...To gain insight into the inelastic behavior of piles, the response of a vertical pile embedded in dry sand and subjected to cyclic lateral loading was studied experimentally in centrifuge tests conducted in Laboratoire Central des Ponts et Chaussees. Three types of cyclic loading were applied, two asymmetric and one symmetric with respect to the unloaded pile. An approximately square-root variation of soil stiffness with depth was obtained from indirect in-flight density measurements, laboratory tests on reconstituted samples, and well-established empirical correlations. The tests were simulated using a cyclic nonlinear Winkler spring model, which describes the full range of inelastic phenomena, including separation and re-attachment of the pile from and to the soil. The model consists of three mathematical expressions capable of reproducing a wide variety of monotonic and cyclic experimentalp-y curves. The physical meaning of key model parameters is graphically explained and related to soil behavior. Comparisons with the centrifuge test results demonstrate the general validity of the model and its ability to capture several features of pile-soil interaction, including： soil plastification at an early stage of loading, ＂pinching＂ behavior due to the formation of a relaxation zone around the upper part of the pile, and stiffness and strength changes due to cyclic loading. A comparison of the p-y curves derived from the test results and the proposed model, as well as those from the classical curves of Reese et al. （1974） for sand, is also presented.展开更多
Objective: To explore the pathophysiological mechanism of the changes in gap junctionalintercellular communication (GJIC) in the myocardial cells after burns. Methods: After the myocardial cellswere cultured and injur...Objective: To explore the pathophysiological mechanism of the changes in gap junctionalintercellular communication (GJIC) in the myocardial cells after burns. Methods: After the myocardial cellswere cultured and injured with hypoxia and burn serum, the GJIC in the cells was detected with scrapeloading and dye transfer. Meanwhile, the viability, cytosolic free Ca2+ concentration and Ca2+ influx of themyocardial cells were determined. Results: The cytosolic free Ca2+ concentration and the cellulartransmembrane Ca2+ influx were significantly increased but the viability of the cells markedly decreased afterthe injury. The LY fluorescence reached 4 rows of cells from the scrape line in the normal myocardial cells.The GJIC was blocked at the first hour after hypoxia or hypoxia and burn serum injury. The LY fluorescencewas limited to the primary loads cells at the sixth hour after hypoxia and the third hour after hypoxia andburn serum injury. Conclusion: The function of GJIC in the myocardial cells is to maintain high ordersynchronous contraction of the myocardium. After burns, the runaway calcium homeostasis and impairmentof GJIC function would be accused to be the pathological basis for myocardial heterogeneous behavior.展开更多
<div style="text-align:justify;"> A novel method for tri-band microstrip array antenna with improvement in the bandwidth by incorporating wide slots and additional resonators which is gap-coupled to th...<div style="text-align:justify;"> A novel method for tri-band microstrip array antenna with improvement in the bandwidth by incorporating wide slots and additional resonators which is gap-coupled to the non-radiating edges of a radiating element is presented. The experimental results show that two element slot-loaded gap-coupled microstrip array antenna gives a ?10 dB return loss band-width for three bands. The design specifications, radiation patterns and gain of the proposed antennas are presented and described. </div>展开更多
基金EU Fifth Framework Program: Environment, Energy and Sustainable Development Research and Technological Development Activity of Generic Nature: The Fight Against Natural and Technological Hazards, Research Project QUAKER Under Contract No. EVG1–CT–2002–00064
文摘To gain insight into the inelastic behavior of piles, the response of a vertical pile embedded in dry sand and subjected to cyclic lateral loading was studied experimentally in centrifuge tests conducted in Laboratoire Central des Ponts et Chaussees. Three types of cyclic loading were applied, two asymmetric and one symmetric with respect to the unloaded pile. An approximately square-root variation of soil stiffness with depth was obtained from indirect in-flight density measurements, laboratory tests on reconstituted samples, and well-established empirical correlations. The tests were simulated using a cyclic nonlinear Winkler spring model, which describes the full range of inelastic phenomena, including separation and re-attachment of the pile from and to the soil. The model consists of three mathematical expressions capable of reproducing a wide variety of monotonic and cyclic experimentalp-y curves. The physical meaning of key model parameters is graphically explained and related to soil behavior. Comparisons with the centrifuge test results demonstrate the general validity of the model and its ability to capture several features of pile-soil interaction, including： soil plastification at an early stage of loading, ＂pinching＂ behavior due to the formation of a relaxation zone around the upper part of the pile, and stiffness and strength changes due to cyclic loading. A comparison of the p-y curves derived from the test results and the proposed model, as well as those from the classical curves of Reese et al. （1974） for sand, is also presented.
文摘Objective: To explore the pathophysiological mechanism of the changes in gap junctionalintercellular communication (GJIC) in the myocardial cells after burns. Methods: After the myocardial cellswere cultured and injured with hypoxia and burn serum, the GJIC in the cells was detected with scrapeloading and dye transfer. Meanwhile, the viability, cytosolic free Ca2+ concentration and Ca2+ influx of themyocardial cells were determined. Results: The cytosolic free Ca2+ concentration and the cellulartransmembrane Ca2+ influx were significantly increased but the viability of the cells markedly decreased afterthe injury. The LY fluorescence reached 4 rows of cells from the scrape line in the normal myocardial cells.The GJIC was blocked at the first hour after hypoxia or hypoxia and burn serum injury. The LY fluorescencewas limited to the primary loads cells at the sixth hour after hypoxia and the third hour after hypoxia andburn serum injury. Conclusion: The function of GJIC in the myocardial cells is to maintain high ordersynchronous contraction of the myocardium. After burns, the runaway calcium homeostasis and impairmentof GJIC function would be accused to be the pathological basis for myocardial heterogeneous behavior.
文摘<div style="text-align:justify;"> A novel method for tri-band microstrip array antenna with improvement in the bandwidth by incorporating wide slots and additional resonators which is gap-coupled to the non-radiating edges of a radiating element is presented. The experimental results show that two element slot-loaded gap-coupled microstrip array antenna gives a ?10 dB return loss band-width for three bands. The design specifications, radiation patterns and gain of the proposed antennas are presented and described. </div>
