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151.
The effects of aging temperature and time on the hardness and impact toughness of a copper-bearing high-strength low-carbon steel were investigated. The hardness of the aged samples reached maxima after 1 h and 5 h of aging at 500 and 450℃, respectively; this increase in hardness was followed by a decrease in hardness until a temperature of 700℃, at which secondary hardening was observed. The impact toughness of the aged steel was found to be higher for 5 h of aging. Transmission electron microscopy confirmed the presence of carbide and copper precipitates; also, the secondary hardening could be the result of the transformation of austenite (formed in the aging treatment) to martensite. Differential scanning calorimetry of the steel was performed to better understand the precipitation behavior. The results revealed that the precipitation of the steel exhibited two significant stages of copper precipitate nucleation and coarsening of the precipitates, with corresponding activation energies of 49 and 238 kJ·mol-1, respectively.  相似文献   
152.
According to Vening Meinesz-Moritz (VMM) global inverse isostatic problem, either the Moho density contrast (crust-mantle density contrast) or the Moho geometry can be estimated by solv-ing a non-linea...  相似文献   
153.
ATM protein kinase: the linchpin of cellular defenses to stress   总被引:1,自引:1,他引:0  
ATM is the most significant molecule involved in monitoring the genomic integrity of the cell. Any damage done to DNA relentlessly challenges the cellular machinery involved in recognition, processing and repair of these insults. ATM kinase is activated early to detect and signal lesions in DNA, arrest the cell cycle, establish DNA repair signaling and faithfully restore the damaged chromatin. ATM activation plays an important role as a barrier to tumorigenesis, metabolic syndrome and neurodegeneration. Therefore, studies of ATM-dependent DNA damage signaling pathways hold promise for treatment of a variety of debilitating diseases through the development of new therapeutics capable of modulating cellular responses to stress. In this review, we have tried to untangle the complex web of ATM signaling pathways with the purpose of pinpointing multiple roles of ATM underlying the complex phenotypes observed in AT patients.  相似文献   
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This paper is a technical study of the systematic observations and computations made by Mu?yī al-Dīn al-Maghribī (d. 1283) at the Maragha observatory (north-western Iran, c. 1259–1320) in order to newly determine the parameters of the Ptolemaic lunar model, as explained in his Talkhī? al-majis?ī, “Compendium of the Almagest.” He used three lunar eclipses on March 7, 1262, April 7, 1270, and January 24, 1274, in order to measure the lunar epicycle radius and mean motions; an observation on April 20, 1264, to determine the lunar eccentricity; an observation on August 29, 1264, to test the model; and another on March 15, 1262, for measuring the lunar parallax. In the second period of activity at the Maragha observatory, Shams al-Dīn Mu?ammad al-Wābkanawī (c. 1254–1320) adopted all of al-Maghribī’s parameter values in his Zīj, but decreased his value for the mean longitude of the moon at epoch by 0;13,11 $^{\circ }$ . By comparing the times of the new moons and lunar eclipses in the period of 1270–1320 as computed from the astronomical tables of the Maragha tradition with the true modern ones, it is argued that this correction was very probably the result of actual observations.  相似文献   
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This paper aims to identify the best indicator in forecasting inflation in Malaysia. In methodology, the study constructs a simple forecasting model that incorporates the indicator/variable using the vector error correction (VECM) model of quasi‐tradable inflation index and selected indicators: commodity prices, financial indicators and economic activities. For each indicator, the forecasting horizon used is 24 months and the VECM model is applied for seven sample windows over sample periods starting with the first month of 1980 and ending with the 12th month of every 2 years from 1992 to 2004. The degree of independence of each indicator from inflation is tested by analyzing the variance decomposition of each indicator and Granger causality between each indicator and inflation. We propose that a simple model using an aggregation of indices improves the accuracy of inflation forecasts. The results support our hypothesis. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
156.
近年来智能网联汽车发展迅速,云端预先存储的道路参数信息对于提升网联汽车的悬架控制以及检测路面不规则度至关重要。目前关于道路参数估计的工作大多在单个车辆上完成,此类算法对于车辆模型不确定性以及测量误差较敏感。针对该问题,提出了一种新的协同式估计架构,该架构能够充分利用多个同质的网联汽车的测量信息以提高估计精度。首先,在云端利用前方行驶的全部车辆的数据对高斯过程模型进行训练以通过众包方式获取道路参数的估计结果。然后,该结果以未测量的方式发送到后方相邻车辆,后方单个车辆结合自车车载传感器(如加速度计、横摆角速度以及侧倾角速度)和由云端获取的基于众包高斯过程估计结果,使用卡尔曼滤波对该估计结果进一步优化。进而估计结果被发送到云端以更新高斯过程模型。大量的仿真实验结果表明,以该种方式使用云端估计的道路参数作为额外的未测量信息能够提高道路参数的估计精度,验证了该算法的有效性。  相似文献   
157.

The remodeling of the mitochondrial network is a critical process in maintaining cellular homeostasis and is intimately related to mitochondrial function. The interplay between the formation of new mitochondria (biogenesis) and the removal of damaged mitochondria (mitophagy) provide a means for the repopulation of the mitochondrial network. Additionally, mitochondrial fission and fusion serve as a bridge between biogenesis and mitophagy. In recent years, the importance of these processes has been characterised in multiple tissue- and cell-types, and under various conditions. In skeletal muscle, the robust remodeling of the mitochondrial network is observed, particularly after injury where large portions of the tissue/cell structures are damaged. The significance of mitochondrial remodeling in regulating skeletal muscle regeneration has been widely studied, with alterations in mitochondrial remodeling processes leading to incomplete regeneration and impaired skeletal muscle function. Needless to say, important questions related to mitochondrial remodeling and skeletal muscle regeneration still remain unanswered and require further investigation. Therefore, this review will discuss the known molecular mechanisms of mitochondrial network remodeling, as well as integrate these mechanisms and discuss their relevance in myogenesis and regenerating skeletal muscle.

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