叠层芯片应用的封装挑战与解决方法

叠层管芯封装的不断发展导致该技术能有效地在同一基底内增大电子器件的功能和容量,作为单个芯片。蜂窝电话及其它消费类产品中叠层芯片封装的应用增长促使能够在给定封装尺寸中封装多层芯片。介绍了叠层芯片封装技术中最主要是满足总封装高度的要求。用于叠层芯片封装的技术实现方法包括基片减薄、薄裸芯片贴装、小形貌引线键合、与无支撑的边缘键合以及小偏倒成形等。集中介绍了叠层管芯互连要求。介绍了倒装芯片应用中的正向球形键合、反向球形键合和焊凸凸焊技术,讨论了优点和不足。说明球形键合机的发展能够满足叠层芯片封装的挑战,即超低环形状、长引线跨距和悬空键合等。     

500nA电源监控器延长便携式应用电池寿命

通过实际应用电路展示,介绍了采用LTC2934和LTC2935超低功率监控器提供准确电压监视和微处理器控制,从而实现便携应用电池寿命的延长。     

正确选择电源管理方案，提升系统性能并延长电池寿命

有了无线技术,用户就真正实现了"网络随行".然而无线设备无法长时间连接固定电源,因此如果仅靠电池供电的话,很快就能把电池电量消耗完.无论采用何种化学技术,电池都只能存储有限的电量,当电量耗尽时均需要替换或充电.加强对电源管理问题的重视可有助于延长电池的寿命.基站等一些不用依靠电池的无线系统必须在兼顾能源效率的前提下,才能实现高性能指标.     

针对微控制器应用的MIPS32 M4K内核影子寄存器

RISC架构为微控制器领域带来了许多优势,例如与CISC架构相比,它对程序编译器更加友好,而且在硅面积方面也非常经济。     

Trust and community: Exploring the meanings,contexts and dynamics of community renewable energy

Community renewable energy projects have recently been promoted and supported in the UK by government policy. A community approach, it is argued in the rhetoric of both government and grassroots activists will change the experience and outcomes of the energy sustainable technology implementation. In this paper, we consider how interpersonal and social trust is implicated in the different meanings given to community in RE programmes and projects, and in the qualities and outcomes that are implied or assumed by taking a community approach. We examine how these meanings play out in examples of projects on the ground, focusing on two contrasting cases in which the relationships between those involved locally have exhibited different patterns of cohesiveness and fracture. We argue that trust does have a necessary part to play in the contingencies and dynamics of community RE projects and in the outcomes they can achieve. Trust between local people and groups that take projects forward is part of the package of conditions which can help projects work. Whilst trust may therefore be functional for the development of community RE and potentially can be enhanced by the adoption of a community approach, this cannot be either assured or assumed under the wide diversity of contexts, conditions and arrangements under which community RE is being pursued and practiced.     

Bioaccumulation, biotransformation, and biochemical effects of brominated diphenyl ethers in juvenile lake trout (Salvelinus namaycush)

Juvenile lake trout (Salvelinus namaycush) were exposed to three dietary concentrations (0, approximately 2.5, and approximately 25 ng/g per BDE congener) of 13 BDE congeners (3-10 Br atoms) in the laboratory for 56 days, followed by 112 days of clean food, to examine bioaccumulation parameters and potential biochemical effects. The bioaccumulation of BDEs by the trout was highly influenced by biotransformation, via debromination, which resulted in bioaccumulation parameters that were much different than would be expected based on studies of chlorinated organic compounds (e.g., PCBs). Half-lives (t1/2's) for some BDE congeners (e.g., BDE-85 and -190) were much lower than expected based on their Kow, which was likely due to biotransformation, whereas t1/2's of other BDE congeners (e.g., BDE-66, -77, -153, and -154) were much longer than anticipated based on Kow. This was likely because the metabolites of BDE formed via debromination had the same chemical structure of these BDE congeners, which supplemented measured concentrations. The detection of three BDE congeners (an unknown penta, BDE-140, and an unknown hexa) in the fish that were not present in the food or in the control fish provide further evidence forthe debromination of BDEs. Half-lives of BDEs ranged from 38 +/- 9 to 346 +/- 173 days and biomagnification factors ranged from 1.6 (BDE-190) to 45.9 (BDE-100), but these bioaccumulation parameters need to be viewed with caution because they were highly influenced by debromination and relative abundance of individual BDEs that the fish were exposed to. CYP1A enzyme activity, measured as EROD, and free tri-iodothyronine (T3) concentrations in the plasma of lake trout varied significantly throughout the experiment but were not related to BDE exposure. In contrast, plasma levels of thyroxine levels (T4) were lower in both groups of PBDE-exposed fish compared with control fish after 56 days of exposure, and after 168 days in the high dose, suggesting that PBDEs may influence thyroid homeostasis at levels that are higher than what is normally found in the environment.     

Aniline in vegetable and fruit samples from the Canadian total diet study

An isotope dilution method based on solvent extraction followed by GC–MS analysis was developed and used to determine aniline in vegetable and fruit samples collected from the Canadian total diet study. Aniline was not detected in any of the 23 vegetable samples from the 2005 total diet study at a method detection limit of 0.01 mg kg^–1. Among the 16 fruit samples, it was detected only in apple samples, with an average concentration of 0.278 mg kg^–1. Aniline was not detected in apple samples collected in the 2002, 2003, 2006 or 2007 total diet studies, but it was detected in the apple samples collected from the 2001 and 2004 studies, at concentrations of 0.085 and 0.468 mg kg^–1, respectively. The average aniline concentration for the 2001, 2004 and 2005 apple samples was 0.277 mg kg^–1. Good repeatability of the method was observed with replicate analysis of apple samples, with relative standard deviations (RSD) ranging 3.8–21% and an average of 11%.     

主轴技术进步促进提高生产率、可靠性、性能和设计寿命

更高速和更可靠的主轴是机床工业的主要发展趋势。机床需要完成多种工作任务并要频繁更换刀具。在这种情况下，主轴必须更快和更频繁地加速度和减速度，使主轴／轴承系统承受热载荷。此外，现在主轴要暴露在最为恶劣和不利环境下。