排序方式: 共有80条查询结果,搜索用时 171 毫秒
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2205双相不锈钢焊接收缩变形与残余应力研究 总被引:3,自引:2,他引:1
采用钨极氩弧焊对2205双相不锈钢进行了焊接试验,用回归分析的方法研究了焊接电流、电弧电压、焊接速度和板厚对焊接收缩变形的影响;采用切条法测试了2 mm厚焊接试件的残余应力,找到了纵向残余应力沿焊缝截面的分布规律,并用正交试验方法对焊接工艺参数进行了优化。 相似文献
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Simple closed-loop method to compensate interference asymmetry in time-division duplex MIMO-OFDM systems 总被引:1,自引:0,他引:1
In wireless communications systems with time-division duplex (TDD) deployment, channel reciprocity and symmetric interference between transmitter and receiver sides are two widely-adopted assumptions for the design of optimal adaptation transmission mode. However, in practice, there is an undesirable but non-negligible effect, namely the asymmetric interference, that makes the assumptions no longer valid. In this paper, a simple closed-loop feedback method of compensating interference asymmetry in TDD multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system is proposed. The system makes the estimated interference at transmit-side be able to track the instantaneous receive-side interference dynamically. The proposed method maintains constant frame error rate (FER) by adopting adaptive modulation coding (AMC) and power loading. The final simulations have verified the effectiveness of the new method. 相似文献
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基于大量的室内外试验和理论分析,有关半刚性基层收缩裂缝的影响因素、级配组成和防治措施的深入研究表明,在级配组成方面采用骨架密实结构作为沥青路面基层可以大大减少路面裂缝.同时为减少半刚性基层收缩裂缝采取一定的防治措施非常必要. 相似文献
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电动车加速工况出现的轴向抖动问题,严重影响驾乘人员的主观感受。本文基于台架试验的方法,消除整车的干扰,研究电驱系统本体的轴向抖动问题。综合采用时频分析,对比分析等方法,首先确定了电驱系统轴向抖动的原因,然后对其影响因素进行了深入探讨,并根据研究结果提出改善该问题的设计建议。研究表明,加速工况轴向抖动是由于半轴的阶次激励激发了电驱系统的刚体模态而引起;半轴的阶次振动幅值随半轴安装角度的增大而有所增大,但GI节型半轴对安装角度更敏感;AAR节型半轴的阶次振动幅值远小于GI节型半轴的阶次振动;电驱系统布置设计时,应尽量减小半轴安装角度并使用AAR节型半轴。 相似文献
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《铁道学报》载文被引分析与研究 总被引:1,自引:0,他引:1
依据中国科学引文数据库CSCD,对《铁道学报》载文的被引总况、单篇论文被引频数及其分布、期刊分布和年代分布等运用文献计量学的方法做了被引分析,尤其对载文被引的年代分布进行了较为详尽和深入的研究,建立了相应的数学模型,并据此较精确地确定了半衰期等定量指标。还计算了反映论文被利用情况的普赖斯指数。最后,对该刊的影响力和载文被利用情况以及老化等问题进行了讨论。 相似文献
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In the presence of biofilms, stainless steels(SS) exhibits an increase in corrosion potential, called ennoblement. In the present study, the corrosion potential(Ecorr) behavior of the duplex SS UNS S32760 was recorded simultaneously with the in situ marine biofilm formation in two areas at Arraial do Cabo,Southeastern Brazil. The biofilm at Forno Harbor(an anthropogenically disturbed area) was characterized by higher relative abundances of Bacteria at day 2, followed by diatoms(especially Navicula sp.) on day 10 and dinoflagellates on day 18,whereas no clear trend was recorded at Cabo Frio Island(an undisturbed area). The ennoblement of Ecorr values was site-dependent. In a complementary laboratory assay, biofilms were removed and the Ecorr values registered in sterile conditions for the subsequent 10 days and corroborated in situ results. Understanding biofilms and SS interactions has important implications for materials science and engineering decisions as well as helping to fill in important gaps in this knowledge. 相似文献