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汪小会 《实验室研究与探索》2012,(4):231-233
电子工程技术人员进行集成电路设计应用已很普遍,然而集成电路的功耗和散热是专用集成电路(ASIC)芯片发展的较突出问题。从理论上对集成电路由于寄生负载电容进行充放电、漏电流和亚阈值电流造成的功耗等产生进行探讨,从而找出降低集成电路功耗的多种解决的方法。 相似文献
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目前的薄型细间距球栅阵列（low-profile fine-pitch ball grid array,LFBGA）封装电热联合仿真方法较少考虑电路芯片本身材料的散热能力,因此存在准确性不足的问题。为了解决这个问题,该文提出了一种基于场路耦合的LFBGA封装电热联合仿真方法。该方法建立了LFBGA封装热阻模型,考虑了电流和电压的热能转换以及芯片材料本身的散热能力,并使用场路耦合计算了电热联合芯片散热关系式。此外,该方法还设置了功率取值范围,确保仿真的精确性。通过实验验证,该方法的准确性在电压和电流计算中均高于现有的两种方法。因此,基于场路耦合的LFBGA封装电热联合仿真分析方法能够提供更准确的仿真结果。 相似文献
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EDA仿真是射频集成电路课程教学的重要教学手段。文章以设计一种应用于交通专用短程通信的5.8GHz射频功率放大器为例,对EDA工具在射频集成电路课程教学中的应用进行了探讨;通过EDA仿真,形象地演示出了电路性能的变化,加深了学生对有源电感补偿的CMOS射频功放的理解和认识。 相似文献
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室内油浸式变压器温度场分布受到室内散热系统和运行过程中电磁干扰等因素影响,导致测温传感器测量数据可靠性下降,一定程度上不利于变压器状态评估等相关实验教学工作的开展。针对上述问题,基于有限元分析仿真建立变压器的磁-流体-温升模型,并进行相关热属性参数设置和耦合计算;考虑散热对油温的影响,仿真分析室内散热系统启停下的温升特性关系;最后,根据仿真计算结果,修正异常油温数据。与其他数据修正方法相比,此方法基于建模仿真的形式更有利于学生直观地学习和理解变压器温升机理,可为后续变压器状态评估等相关实验教学工作提供高质量数据支撑。 相似文献
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三维视景仿真在新型装备训练、虚拟实验等领域发挥着重要作用．详细介绍了三维视景仿真软件 Es-perient Creator ,给出了采用Esperient Creator开发三维视景仿真系统的技术路线,对建模、模型优化、交互控制、作品发布等关键技术进行了分析说明,实现了虚拟车间三维视景仿真系统;该系统具有场景漫游、机床操作、轴承拆装等功能．Esperient Creator是一种崭新的三维视景仿真平台,交互功能强大,可广泛应用于视景仿真各个领域,具有广阔应用前景． 相似文献
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以前用Matlab实现三维仿真时,需要用不同的开发平台混合编程才能实现。提出了只需使用Matlab就可实现三维仿真的方法。其方法是:在Matlab程序代码中,调用包含ac格式的三维模型,播放三维模型动画,其中ac文件可以是Matlab自带的,也可以自己制备,因而此方法可实现任何形状物体的三维仿真。 相似文献
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为了研究中冷器散热性能,采用Space Claim建立中冷器模型,运用mesh进行网格划分,通过Fluent软件进行仿真研究.分析了汽车中冷器内部流场分布情况,对不同进口温度、进口速度、翅片厚度以及翅片数量工况下散热性能进行了研究.结果表明:当中冷器的进口温度相同时,其进口速度越小,散热效果越好;当中冷器的进口速度相同时,其进口温度越小,散热效果越好.当中冷器的翅片厚度以及翅片数量越大时,散热效果也更好.计算结果为中冷器的设计提供了理论依据. 相似文献
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针对现有集成电路测试设备结构复杂,功能单一的缺点,本文利用FPGA核心板、D／A模块、A／D模块、电流转换电压电路等器件,采用SOPC技术,设计了一个中小规模通用数字集成电路测试系统,在逻辑功能测试的基础上。实现了74系列中小规模数字集成电路直流性能参数的测试。通过实验,将测试结果与标准的反相器参数进行比较,数据结果一致。表明参数测试仪符合设计要求,设计方案具有一定的参考价值。 相似文献
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Amanda W. Joyce Jessica H. Kraybill Nan Chen Kimberly Cuevas Kirby Deater-Deckard Martha Ann Bell 《Early education and development》2016,27(6):788-804
Research Findings: A total of 81 children participated in a longitudinal investigation of inhibitory control (IC) from 2 to 4 years of age. Child IC was measured via maternal report and laboratory measures under conditions of conflict and delay. Performance on delay IC tasks at 3 years was related to performance on these same tasks at 2 and 4 years, but performance on conflict IC tasks was not related over time. Delay IC task performance was concurrently related to conflict IC task performance in 3- and 4-year-olds but was not related in 2-year-olds. Measures of IC varied in their associations with measures of verbal ability and maternal-report IC. Such findings highlight important similarities and distinctions between conflict and delay IC abilities in their relation to one another and to temperament and language over time. Practice or Policy: Studies of IC and related concepts reveal that children who are regulated enjoy school more and have higher school competence, particularly in mathematics and reading achievement. Because conflict IC and delay IC show unique patterns of development over time, educators can expect classroom behaviors drawing on the state-like conflict IC to show more fluctuation over time than those drawing on the trait-like delay IC. 相似文献
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目前高职院校计算机基础教学的现实情况不容乐观,而且出现了一些新的问题。IC3认证为高职院校的计算机基础教学改革提供了一个良好的途径。但是在引入IC3认证的同时,高职院校要结合自己的实际情况,循序渐进地将这种方式融入到教学改革中来,在实践中不断地进行完善,以达到提高教学质量的目的。 相似文献
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信息共享空间体现的是以用户为主导的服务理念,作为校园学习空间的重要组成部分,信息共享空间物理环境的开发有其自身的特点。基于信息共享空间的服务类型和特征,建立了一个基于服务-社会-空间-技术四个维度的开发框架,利用该框架分析了一个具体的信息共享空间的案例。研究表明,该框架具有一定的通用性,可以适合信息共享空间物理环境开发的各个阶段。 相似文献
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以生物电子等排体原理设计合成了2-[[3-羟苯基]亚氨基]苯酚,测试了其清除DP-PH·的活性,并分别探讨了溶剂效应和作用时间这两个因素对其清除DPPH·的影响。结果表明,目标化合物的半清除率浓度IC50小于10mg／mL,说明化合物具有良好的自由基清除活性;溶剂效应对目标化合物清除DPPH·的活性具有重要影响,在DMF中清除DPPH·的活性最优,IC50为408．5μM,在丙酮中的清除活性较差,IC50为868．54μM;目标化合物随作用时间对DPPH·的清除程度有差异,其对DPPH·的清除作用是随时间变化而缓慢进行的。 相似文献
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Ji Young Choi Sherri Castle Amy C. Williamson Emisha Young Lauren Worley Melissa Long 《Early education and development》2016,27(6):751-769
Research Findings: The purpose of this study was to examine the potential contribution of teacher–child interactions to residualized Inhibitory Control (IC) gains over approximately a six-month period for preschoolers from predominantly low-income households. The study also explored whether the association between quality of teacher–child interactions and IC gains depends on children’s IC skills upon classroom entry and their household income-to-needs ratio. The study included 169 preschoolers from 51 classrooms in a Head Start program run by an agency in a large city in Oklahoma. Children’s IC skills were assessed in fall (time 1) and spring (time 2), and teacher–child interaction quality was observed at fall (i.e., September through November). Results from Hierarchical Linear Modeling (HLM) did not show significant effects of high-quality teacher–child interactions on residualized IC gains over six months. However, results showed that children who initially presented poor IC skills displayed higher gains in their IC skills at spring when they were in classrooms practicing high-quality teacher–child interactions, as defined by emotional support and classroom organization. Practice or Policy: Emotionally supportive and well-organized classrooms in Head Start programs may benefit early IC development, especially for children presenting poor IC skills at classroom entry. 相似文献
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在测试74LS系列IC的过程中,为解决插拔被测IC时测试插座带电的问题,设计了一种由两片单片机组成、上位机为下位机程控供电的新型数字IC测试仪,该测试仪实现了插拔被测IC时测试插座完全断电,并具有时钟和温度显示等辅助功能。 相似文献
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Seung-Hee Claire Son Ji Young Choi Kyong-Ah Kwon 《Early education and development》2019,30(4):456-477
Research Findings. The present study examined patterns of longitudinal associations between inhibitory control (IC) and early academic skills during the preschool and kindergarten years. Using data from the Head Start Family and Child Experiences Survey Cohort 2009 (FACES 2009) (N = 939), a national data set of predominantly low-income children attending Head Start, two models were compared: (1) a lagged path model predicting subsequent academic skills based on prior IC skills and (2) a cross-lagged path model predicting reciprocal associations between IC and academic skills. Our results showed a better model fit for the cross-lagged path model with bidirectional associations. Prior IC predicted subsequent early reading and math skills during the preschool and kindergarten years; simultaneously, prior early math skills, but not reading skills, predicted subsequent IC. The reciprocal associations between IC and early math were consistently identified for multiple groups of children, regardless of their gender or home-language use (i.e., monolingual versus dual language learners). Practice or Policy. This study showcases group-general patterns of reciprocal relationships between IC and early math. The findings suggest that stimulation of both skills could lead to stronger skill sets and successful school outcomes. Early education and intervention programs may provide integrated developmental opportunities of IC and academic skills for successful school readiness. 相似文献
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将利用分立器件设计的4通道神经信号再生电子系统成功地应用于大鼠和家兔的活体动物实验,再生了它们的神经信号．采用相同的原理,用CSMC0．6μm CMOS工艺设计实现了单通道神经信号再生集成电路．电路由增益可调的神经信号探测电路、缓冲器和神经功能电激励电路构成．电路采用±2．5V双电源电压供电．芯片尺寸为1．42mm×1．34mm．在片测试电路的静态功耗小于10mW,输出电阻为118mΩ,3dB带宽大于30kHz,增益在50～90dB可调．电路芯片与卡肤电极、针状双体电极一起,用于大鼠的神经信号再生的活体动物实验,成功地再生了大鼠的坐骨神经和脊髓神经信号． 相似文献