可重构视频阵列处理器测试平台设计与实现

针对可重构视频阵列处理器的设计要求及传统测试方法测试视频编解码系统时速度慢、精度低和可观测性不强的问题。开发了基于Qt的用户界面,设计实现了以现场可编程门阵列(Field programmable gate-array,FPGA)为核心的软硬件协同测试平台。在PC端实现以软件仿真为基础的数据传输与图像重现,在FPGA端实现以可重构视频阵列处理器为基础的视频编解码算法并行映射。实验结果表明,在工作频率为100 MHz时,FPGA与PC之间可正确传输数据并满足算法测试时不同测试用例的更换需求,具有较好的可观测性。     

铅酸电池板栅的轻量化

铅酸电池板栅是铅酸电池的重要构件之一,对铅酸电池电化学性能和商业化应用均产生重要影响。板栅轻量化要求既能实现铅酸电池整体减重,又不能明显牺牲电池的充放电性能,甚至能同时增加电池的能量密度和寿命。非铅的轻质金属板栅、合金板栅及其相应的板栅结构设计等是实现铅酸电池板栅轻量化的几个重要方向。文章综述了这几个方向的研究现状,尤其是对板栅的选材、机械性能、耐腐蚀性能、电化学性能及板栅结构轻质化技术路线等方面的优势和不足进行了分析。最后,为促进新型轻量化板栅的研发,提出未来几个可能的研究方向。     

基于GPS载噪比下降的太阳射电暴检测方法

利用太阳射电暴影响全球定位系统(global positioning system, GPS)性能这一特征,提出一种基于GPS载噪比下降的太阳射电暴检测方法。首先计算观测地的太阳高度角,接着筛选出“降点”和“升点”用于确定单个观测地单颗卫星的波谷时间区间,最后综合多颗卫星和多个观测地得到太阳射电暴的检测结果。实验结果表明:太阳射电暴检出率随太阳入射角的增大而增大,在L2频段对600太阳流量单位(solar flux unit, SFU)以上的太阳射电暴检出率达到80%以上,在L2频段检出效果优于L1。该检测方法识别率高,成本低,不依赖于射电望远镜,能进行全天候实时的监测。     

Reliability Analysis of Supply Chain System with the Multi-Suppliers and Single Demander

The time-dependent solution of a kind of supply chain system with the multi-suppliers and single demander is investigated in this paper. By choosing state space and defining operator of system, we transfer model into an abstract Cauchy problem. We are devoted to studying the unique existence of the system solution and its exponential stability by using the theory of C_0-semigroup. We prove that the system operator generates C_0-semigroup by the theory of cofinal operator and resolvent positive operator. We derive that the system has a unique nonnegative dynamic solution exponentially converging to its steady-state one which is the eigenfunction corresponding eigenvalue 0 of the system operator.     

JDO的分析与研究

文章介绍了Java数据对象JDO的概念和优势,分析了JDO技术与串行化、XML和自定义文件格式的区别和联系,探讨了JDO和ODBMS、O/R映射的关系、JDO和带CMP的EJB之间的关系及JDO和JDBC的关系。     

外加轴向磁场对短路过渡的影响

为提高短路过渡频率、减少焊接飞溅,分别通过施加直流与交变轴向磁场,研究了轴向磁场对短路过渡的影响规律,分析了高速摄像、电流电压信号以及熔滴在磁场作用下的短路过渡受力情况.结果表明:当直流磁场励磁电流为4 A时,短路过渡频率达到最大值;当交流磁场励磁电流为9 A、磁场频率为100 Hz时,短路过渡频率达到最大值,这与电流...     

德士古渣油气化系统数学模拟

对德士古渣油气化系统进行了过程分析,建立了单元设备物料和热量衡算的数学模型,提出了计算气化炉微量组分的方法。运用序贯模块法对该系统进行了稳态模拟计算,结果同设计值和工厂值吻合较好。     

Maize HapMap2 identifies extant variation from a genome in flux

Whereas breeders have exploited diversity in maize for yield improvements, there has been limited progress in using beneficial alleles in undomesticated varieties. Characterizing standing variation in this complex genome has been challenging, with only a small fraction of it described to date. Using a population genetics scoring model, we identified 55 million SNPs in 103 lines across pre-domestication and domesticated Zea mays varieties, including a representative from the sister genus Tripsacum. We find that structural variations are pervasive in the Z. mays genome and are enriched at loci associated with important traits. By investigating the drivers of genome size variation, we find that the larger Tripsacum genome can be explained by transposable element abundance rather than an allopolyploid origin. In contrast, intraspecies genome size variation seems to be controlled by chromosomal knob content. There is tremendous overlap in key gene content in maize and Tripsacum, suggesting that adaptations from Tripsacum (for example, perennialism and frost and drought tolerance) can likely be integrated into maize.     

A genetic interaction network of five genes for human polycystic kidney and liver diseases defines polycystin-1 as the central determinant of cyst formation

Autosomal dominant polycystic liver disease results from mutations in PRKCSH or SEC63. The respective gene products, glucosidase IIβ and SEC63p, function in protein translocation and quality control pathways in the endoplasmic reticulum. Here we show that glucosidase IIβ and Sec63p are required in mice for adequate expression of a functional complex of the polycystic kidney disease gene products, polycystin-1 and polycystin-2. We find that polycystin-1 is the rate-limiting component of this complex and that there is a dose-response relationship between cystic dilation and levels of functional polycystin-1 following mutation of Prkcsh or Sec63. Reduced expression of polycystin-1 also serves to sensitize the kidney to cyst formation resulting from mutations in Pkhd1, the recessive polycystic kidney disease gene. Finally, we show that proteasome inhibition increases steady-state levels of polycystin-1 in cells lacking glucosidase IIβ and that treatment with a proteasome inhibitor reduces cystic disease in orthologous gene models of human autosomal dominant polycystic liver disease.     

IFT54 regulates IFT20 stability but is not essential for tubulin transport during ciliogenesis

Intraflagellar transport (IFT) is required for ciliogenesis by ferrying ciliary components using IFT complexes as cargo adaptors. IFT54 is a component of the IFT-B complex and is also associated with cytoplasmic microtubules (MTs). Loss of IFT54 impairs cilia assembly as well as cytoplasmic MT dynamics. The N-terminal calponin homology (CH) domain of IFT54 interacts with tubulins/MTs and has been proposed to transport tubulin during ciliogenesis, whereas the C-terminal coiled-coil (CC) domain binds IFT20. However, the precise function of these domains in vivo is not well understood. We showed that in Chlamydomonas, loss of IFT54 completely blocks ciliogenesis but does not affect spindle formation and proper cell cycle progression, even though IFT54 interacts with mitotic MTs. Interestingly, IFT54 lacking the CH domain allows proper flagellar assembly. The CH domain is required for the association of IFT54 with the axoneme but not with mitotic MTs, and also regulates the flagellar import of IFT54 but not IFT81 and IFT46. The C-terminal CC domain is essential for IFT54 to bind IFT20, and for its recruitment to the basal body and incorporation into IFT complexes. Complete loss of IFT54 or the CC domain destabilizes IFT20. ift54 mutant cells expressing the CC domain alone rescue the stability of IFT20 and form stunted flagella with accumulation of both IFT-A component IFT43 and IFT-B component IFT46, indicating that IFT54 also functions in IFT turn-around at the flagellar tip.