基于自适应控制休眠周期的LTE DRX机制研究

针对LTE系统的动态不连续接收机制,系统分析了动态控制LTE DRX周期算法的引入背景,提出了一种基于自适应控制休眠周期的LTEDRX机制,并通过仿真平台对其性能进行了仿真验证。仿真结果表明该算法在能耗和时延2方面均具有良好的性能,可以实现两者之间的有效折衷与权衡。     

Deformation map for hot working of AA2024 composites reinforced with SiC particle

The dynamic deformation behavior of Al 2024 composites reinforced with 1 and 8 μm SiCp (15 vol.%) has been investigated in the temperature range of 370 to 500°C and strain rate range of 0.1 to 3.0/sec by torsion testing. Processing maps showing the variation of the efficiency of power dissipation expressed by [2m/(m+l)], where m is the strain rate sensitivity, with temperature and strain rate have been described for the composites. Also, the domain of dynamic recrystallization (DRX) and peak efficiency of the composites were analyzed to suggest an optimum hot working condition for DRX. The SiCp/A12024 composite with 8 (μm SiCp showed 40% efficiency at the DRX domain (370~460°C, 0.1~0.5/sec). The optimum temperature and strain rate condition for the DRX of the composites is 430~450°C and 0.5/sec. The characteristics of these results were discussed with the help of microstructural observation during hot deformation. This article based on a presentation made in the symposium “The 1^st Korea—Japan Structural Dynamic Symposium”, held at Sunchon National University, Sunchon, Korea, August 5–8, 1999 under the auspices of The Korean Insitute of Metals and Materials and Research and Development Center for Automobile Parts and Materials.     

移动互联网终端节能的研究

本文首先介绍了新兴应用的流量特征,然后分析了影响终端能耗的因素和传统的节电方案非连续接收(DRX)机制,最后综述了目前最新研究的两种优化的DRX节能机制。     

Mechanical properties of Mg-Gd-Zr alloy by Nd addition combined with hot extrusion

The effect of Nd addition on the microstructure and mechanical properties of as-extruded Mg-9Gd-0.5Zr (wt.%) alloy was investigated. The Mg-9Gd-0.5Zr and Mg-9Gd-2Nd-0.5Zr alloys were extruded at 673 K. The elongated non-dynamic recrystallized (un-DRXed) grains disappear after adding Nd, and uniformly distributed dynamic recrystallized grains with a grain size of 1.68 μm were obtained in the alloy. In addition, numerous nano-Mg₅(Gd,Nd) particles were found to precipitate dynamically in the Mg-9Gd-2Nd-0.5Zr alloy, which gave rise to the dynamic recrystallization process via providing nucleation energy through hindering the release of deformation energy and promoting an increase in the strength through the Orowan strengthening mechanism. Moreover, the dynamically recrystallized (DRXed) grains have a weak texture, which plays a significant role in improving the ductility. Therefore, the Nd addition favors the improvement of strength and elongation for the as-extruded Mg-9Gd-0.5Zr alloy, simultaneously.     

AZ31镁合金热轧变形的动态再结晶机制

在轧制温度603~703 K、轧制压下量20%~40%、应变速率4~16 s-1下对AZ31镁合金进行轧制变形,研究轧制压下量、应变速率和变形温度对AZ31镁合金变形组织的影响,分析了镁合金的动态再结晶机制。结果表明：应变速率和变形温度不仅影响动态再结晶进行的程度,而且能够改变再结晶的方式或形核机制。当轧制应变速率= 13.9 s-1,变形温度T=603 K时,再结晶方式为孪生动态再结晶;变形温度升高到703 K时,沿晶界有链状新晶粒出现。当变形温度T= 673 K,应变速率= 11.35 s-1时,再结晶方式以孪生动态再结晶为主;应变速率降低到= 4 s-1时,再结晶方式以旋转动态再结晶为主。     

铸态Ti-46Al-6(Cr, Nb, Si, B)合金的高温流变行为及其组织演变

以3次真空自耗熔炼的Ti-46Al-6(Cr,Nb,Si,B)(at%)(以下简称G4合金)合金为对象,采用恒温等应变速率热模拟压缩试验研究G4合金在1050～1250℃及0.001～1s-1应变速率下的高温流变行为和组织演变。结果表明,在高温变形过程中,G4合金呈现先硬化后软化的流变行为特征,组织由粗大的铸态γ+γ/α2近片层组织演变为细小的近等轴γ+α2组织;造成G4合金流变软化和组织演变的主要原因是动态再结晶(DRX)。变形温度和应变速率是影响G4合金高温流变和组织演变的2个主要因素。铸态G4合金在高温下的变形机制以γ/α2层片晶团的扭折、弯曲、球化和DRX以及γ晶粒的拉长、破碎和DRX为主,孪生变形也起到了一定的辅助作用。其最佳高温塑性变形温度为1150℃,应变速率应不大于0.1s-1。     

TD-LTE系统下的DRX过程的改进与实现

随着移动终端业务的丰富以及智能手机的普及,移动终端电池的续航能力在成为业界关注热点的同时也遇到了严峻的挑战.在LTE系统无线高层协议中,为进一步支持多种业务和大量数据的传输,DRX(非连续接收)机制作为降低终端功耗的重要方法被引入.本文不仅详细描述了DRX在空闲状态和连接状态下的不同原理和机制,而且给出了相应的实现流程与算法,并在此基础上优化了连接态下的DRX算法,从而避免了因无效配置造成的信令开销增大等问题.最后根据不同业务的特性,给出了DRX机制在不同移动业务中的实现,从而更好地改善了终端能耗和信令开销等性能.     

Hot Working of High Nitrogen Austenitic Stainless Steel

With hot rolling in laboratory and Gleeble thermal simulator,the hot working of a high nitrogen austenitic stainless steel(HNASS)was researched.The results showed that dynamic recovery(DRV)and dynamic recrystallization(DRX)in HNASS occurred during hot working,and both of them had well-defined stress peaks in flow curves under different conditions.During hot rolling experiment at temperature from 950 to 1050 ℃,recrystallization phenomenon does not take place in test material until the deformation ratio is up to 40%.Recrystallization influences remarkably the strength and ductility of material,and the test HNASS possesses better combination of strength with ductility.According to the curve of θ-σ(strain hardening rate-steady state stress),the DRX critical strain of test material was determined.Also,the activation energy of hot working was calculated to be 746.5 kJ/mol and the equation of hot working was obtained.     

Dynamic Power Saving Mechanism for 3G UMTS System

This paper investigates the power saving mechanism of Universal Mobile Telecommunications System (UMTS). UMTS discontinuous reception (DRX) is exercised between the network and a mobile station (MS) to save the power of the MS. The DRX mechanism is controlled by two parameters: the inactivity timer threshold t _I and the DRX cycle t _D . Analytic analysis and simulation model are proposed to study the optimal t _I and t _D selections that maximize the MS power saving under the given mean packet waiting time constraint. We also devise an adaptive algorithm called dynamic DRX (DDRX). This algorithm dynamically adjusts the t _I and t _D values to enhance the performance of UMTS DRX. Our study quantitatively shows how to select the best inactivity timer and DRX cycle values for various traffic patterns. We also show that DDRX nicely captures the user traffic patterns, and always adjusts the t _I and t _D close to the optimal values.