摘要：This paper presents a design method of ByPassing Unit(BPU) in 32-bit Digital Signal Processor(DSP)-MD32. MD32 is realized in 0,18μm technology, 1.8V and 200 MHz working clock. It focuses on the Reduced Instruction Set Computer(RISC) architecture and DSP computation capability thoroughly, extends DSP with various addressing modes in a customized DSP pipeline stage architecture. The paper also discusses the architecture and circuit design of bypassing logic to fit MD32 architecture. The parallel execution of BPU with instruction decode in architecture level is applied to reduce time delay. The optimization of circuit that serial select with priority is analyzed in detail, and the result shows that about half of time delay is reduced after this optimization. Examples show that BPU is useful for improving the DSP's *** forwarding logic in MD32 realizes 8 data channels feedback and meets the working clock limit.

摘要：In the preprocessing phase, the global terrain model is partitioned into blocks with their feature points being picked out to generate TIN model for each terrain block, then the multi-resolution models of terrain organized in the form of quad-tree is created bottom-up. Cracks between terrain blocks are avoided by inserting vertices to form common boundaries. At run-time, a view-dependent LOD algorithm is used to control the loading and unloading of the proper blocks by an additional synchronous thread. To eliminate the artifacts created by LOD transitions, geomorphing is used in real-time. These rendering strategies increase the throughput of GPU and avoid imbalance of load among CPU, GPU and Disk I/O. Experimental results show that the system can perform visually smooth rendering of large-scale terrain scenes with fine quality at an average rate of 80 fps.

摘要：应用定量化的分析工具,对加工中心立柱结构进行了可适应动态设计过程分析。提出产品可适应性的综合评价指标,建立了产品可适应性综合评价模型。应用多级模糊综合评价方法在对产品功能适应性等多种评价指标进行初级评价的基础上,进行了二级综合评价,得到了VMC850加工中心立柱产品可适应性综合评价等级,从而为进一步改进产品设计提供了指导和修改依据。在方案设计阶段,通过给出各方案的可适应性度量数值以及对修改设计的难易程度做出定量评价,可有效地指导机床结构设计过程。

摘要：采用有限元分析方法,分析了压电双晶片悬臂梁的位移形变特征。研究了金属弹性层、压电陶瓷片的材料属性及几何尺寸对双晶片偏转位移的影响;计算了双晶片的弹性模量、厚度以及加载电压与位移形变产生弯应力的关系;通过位移测试、弯应力测试等相关实验对有限元分析进行了验证。当加载电压为60V(120Vp-p)时,双晶片的偏转位移和弯应力分别为166μm和34.7m.N,实验结果证明本文所建的有限元模型是合理有效的。此外,测试了压电双晶片的振动特性,测得其谐振频率为310Hz,在该频率下加载20Vp-p电压,其端部位移输出即可达1.7mm。有限元分析结果及实验验证为压电双晶片结构的优化设计提供了依据。

摘要：Drug delivery systems(DDSs) have been getting more and more attention in the field of cancer therapy with the development of nanotechnology. But remote and noninvasive controlled drug release for improving treatment efficacy and reducing side effects faces great challenge. We report a kind of 'smart' nanocomposites(NCs) that is sensitive to the surrounding temperature by grafting a layer of thermosensitive polymer, poly(N-isopropylacrylamide)(pNIPAm),on the surface of single Cu_7S_4 nanoparticle(NP) via atomtransfer radical polymerization(ATRP). These NCs demonstrate a photothermal conversion efficiency of 25.4% under808-nmnear infrared(NIR) light irradiation and a drug loading content of 19.4%(drug/total NCs, w/w) with a lower critical solution temperature(LCST) of ~38°C. At normal physiological temperature(37°C), only 10.8% of the loaded doxorubicin(DOX) was released at physiological pH value(pH7.4) within 10 h. In the presence of 808-nm irradiation, due to the temperature increment as a result of photothermal effects,DOX was rapidly released.

摘要：Repetitious simulation after modifying parameters of multi-domain physical system based on Modelica often appears in model experiment and optimization design. At present, the solvers based on Modelica need calculate all the coupled blocks during every simulation run after updating parameters. Based on discussing scale decomposition methods of simulation model, subdivision solving strategy and minimum solving strategy are put forward to improve the efficiency of repetitious simulation, by which the numerical solution of the simulation model can be achieved by only calculating the solving sequence influenced by altered parameters. A simplified model of aircraft is used to demonstrate the efficiency of the strategies presented.

摘要：Based on a theoretical motion equation of encapsulated microbubbles within an ultrasound field, the subharmonic characterizations of microbubbles are optimally designed and analyzed by a computer aided design system. The effects of size, shell elasticity and acoustic pressure on subharmonic response of microbubbles are calculated theoretically to obtain the optimal parameters for nondestructive subharmonic imaging. In addition, microbubbles with different shell elasticity are prepared, and their subharmonic responses are measured in vitro. The results of theoretical calculation and acoustic measurement show that good subharmonic enhancement can be obtained by using the encapsulated microbubbles with the mean size of 3 μm, which were prepared from the surfactant solution with the proper ratio of shell material. It is also shown that the best operating acoustic pressure is 200 to 400 kPa for nondestructive subharmonic imaging based on such kind of microbubbles.

摘要：针对软土地层中盾构地中对接冻结加固施工边界条件复杂、形成冻结壁体积小且形状不规则的特点,以上海地区某盾构对接冻结加固工程为原型,按照相似理论设计进行了冻结加固模型试验,分析了冻结过程中地层温度场的分布规律,获得以下结论:在盾构壳体内表面保温的条件下,冻结管内部冻土的平均发展速度是冻结管外部的1.5倍左右;冻结28 h后,冻结管内部冻结壁的温度分布基本稳定,盾构壳体与土体交接面的温度均处于-20℃左右,内部冻结壁的平均温度约为外部的1.9倍。在同圈冻结管的叠加作用下,冻结过程中冻结壁主面和界面的温度变化规律基本一致,仅在冻结初期有少许差别。在外圈冻结管的低温屏蔽作用下,内圈冻结管对外部土体基本不发挥冻结作用,在不同冻结管排间距及多根冻结管交叉冻结的情况下,冻结管外部的冻土扩展规律基本相同,仅两排冻结管之间的土体温度分布存在差别。研究结果表明,盾构地中对接冻结加固形成的冻结壁形状与外圈冻结管的布置形式相似,形成的冻结壁厚度及平均温度在冻结28 h后基本稳定。

摘要：针对铁电材料BST的电容在直流偏场下电性能随温度变化,设计了一种用来检测微小差分电容的电路。采用性能、形状较为一致的BST铁电陶瓷单元电容器配对结构,以电脉冲的方式读取不同温度下材料的充放电电荷数,从而探测辐射到铁电材料上的红外信息。实验结果与理论分析较为吻合,中心频率10Hz、带宽2Hz、放大倍数9000倍。这种BST红外探测器阵列像元信号检测电路具有抗寄生电容干扰强、灵敏度高、容易实现、成本低等优点。改进该探测电路,有望开发出结构简单、性能优良的新一代红外探测器。

摘要：A CAD-based inspection planning strategy for video measuring instrument is proposed to improve manufacturing effec- tiveness. The system consists of a video probe that enables itself to inspect a work piece based on a CAD model. The measurement software includes CAIP module and MDP module. The CAIP module is developed based on a CAD development platform whose kernel is the Open CASCADE. The entire system was tested, and relevant examples show that the system can accomplish automatic inspection planning task for common parts efficiently.