质量比改变压缩比的辛烷值测定机

辛烷值是汽油使用性能的一项重要指标,表示汽油的抗爆震性能。目前国际上公认的标准测试仪器是ASTM-CFR试验机,其工作原理是通过调节气缸高度,改变体积的变化来调节压缩比变化,从而使试样达到最大爆震进行测量。其工作原理是通过采取固定气缸高度,通过等容可变压缩压力系统来调节缸内压强的方式来测定辛烷值.因为质量法是通过控制进气量来改变缸内的压强,所以发动机缸内压强可以比传统的改变气缸高度达到更大的范围。并对辛烷值测定机的控制系统软件进行设计,通过控制相关参数,使其达到稳定状态,使最后的测试结果。     

面向蛇形机器人的三维步态控制的层次化联结中枢模式生成器模型

提高蛇形机器人的三维运动控制能力是提高蛇形机器人环境适应能力的关键之一. 虽然联结中枢模式生成器(Connectionist central pattern generator, CCPG)模型具有复杂度小、适合硬件实现等优点, 但是目前的CCPG模型难以生成相位协调的多自由度运动的控制信号,从而限制了它的三维步态控制能力. 本文根据生物CPG机制的分层结构和运动神经元的功能,提出一个有层次化结构的CCPG (Hierarchical CCPG, HCCPG)模型. HCCPG模型由基本节律信号生成层、模式形成层、运动信号调整层这三个部分组成. 运动信号调整层的运动神经元能够独立地对模式形成层的输出信号的幅值、相位等进行调整,从而较好地 解决了CCPG模型难以生成相位协调的多自由度运动控制信号的问题. HCCPG模型具有步态控制能力强、复杂度小、有良好的扩展性等优点,从而适合用于控制三维步态. 在HCCPG模型的基础上提出一个三维步态控制方法.仿真验证了这个控制方法的有效性.     

食品基质中不同金黄色葡萄球菌肠毒素基因型表达差异研究

目的 比较研究食品基质中不同金黄色葡萄球菌肠毒素(Staphylococcal enterotoxins ,SEs)基因型的蛋白表达差异,为预防金黄色葡萄球菌食物中毒提供参考依据。方法 采用特异聚合酶链反应方法(polymerase chain reaction,PCR)对食品中分离的金黄色葡萄球菌菌株进行肠毒素基因型检测;选择sea、seb、sec、sed等基因型阳性菌株,分别接种于胰酪大豆胨液体培养基(trypticase soy broth,TSB)、牛奶、鸡肉中,按照国家标准GB 4789.10—2016酶联免疫吸附试验法(enzyme linked immunosorbent assay,ELISA)定量检测TSB培养基、牛奶和鲜鸡肉中不同金黄色葡萄球菌肠毒素基因型的蛋白表达量。结果 30株金黄色葡萄球菌中检测到14株肠毒素基因型阳性菌株,所占比例为46.67%,其中sea基因携带率最高(16.67%),而seb、sec、sed、seh则各占6.67%。SEA 在TSB、牛奶、鸡肉3种基质中的平均表达量为7.37 ng/mL,高于SEB、SEC、SED;不同基质环境对肠毒素的表达具有一定影响,如SEA、SEB、SEC、SED在TSB中的表达水平最高,平均表达量为9.04 ng/mL,牛奶次之,鸡肉最低。结论 肠毒素基因型的表达与菌株自身的调控及环境作用密切相关,本研究对肠毒素的产生机制进行初步了解,有助于进一步降低食物中毒风险。     

Cell-free bioassay for measurement of dioxins based on fluorescence enhancement of fluorescein isothiocyanate-labeled DNA probe

This study aims to develop a rapid and sensitive cell-free bioassay of dioxins. It is known that dioxin ligand can bind heterodimeric aryl hydrocarbon receptor (AhR) and triggers the formation of the complex of dioxin-AhR, AhR nuclear translocator (ARNT), and dioxin-responsive element (DRE) region of the DNA. The hypothesis of the proposed method is that if FITC were labeled at the DRE sequence, its fluorescence intensity would be enhanced when the complex forms because the interaction interface of the binding components (AhR, ARNT, and DRE) creates a rather hydrophobic condition that is in favor of FITC emission. Effects of modification site of FITC on the DNA probes on binding efficiency between the complex components and fluorescence emission enhancement were evaluated by surface plasmon resonance and fluorescence analysis, respectively. Results showed that the labeling site at the second base at the 5' end apart from the core region (5'-TNGCGTG-3') of DRE did not obviously interfere with the binding between the DNA probe and dioxin-AhR/ARNT hybrid but presented significant fluorescence emission enhancement. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) was used as the typical toxin in this study. The method had a linear range of 1-100 pM, with detection limit of 0.1 pM (0.64 fg/assay) and coefficient of variation of 5.6% (n = 10, 50 pM TCDD in transformed cytosol). The whole detection cycle was approximately 4 h. The method was also used to estimate the toxic equivalents (TEQ) of 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PeCDD) and 1,2,3,4,7,8-hexachlorodibenzo-p-dioxin (HxCDD). Measurement of TEQs of the mixture of TCDD, PeCDD, and HxCDD were highly consistent with the predicted data. The average recovery using fly ash extract was approximately 93%.     

室外标准田径运动场项目工程管理

室外田径运动场属于较特殊的一类建设项目,在项目实施过程中,极易出现管理困难的局面,也容易产生工程质量问题。通过一室外标准田径运动场在建设施工过程中暴露出来的关键问题,从审核施工图设计、严把原材料关和加强施工现场关键环节控制三个方面对项目实施了有效的工程管理与质量、造价控制,达到了设计标准,确保了建设质量。     

小麦面粉蛋白质特性和面团流变学特性的关系

目的探究小麦面粉蛋白质理化特性与面团流变学特性之间的关系。方法以19份抗旱节水鉴定品种小麦籽粒为试验材料,测定了蛋白质、湿面筋、谷蛋白大聚体含量、沉降指数等面粉蛋白质理化特性,以及粉质参数和拉伸参数等面团流变学特性,采用通径分析研究了面粉蛋白质理化特性与面团流变学特性的关系。结果面粉蛋白质含量对面团吸水率直接增强效应较大,但对稳定时间、拉伸长度的抑制效应较大;谷蛋白大聚体含量对形成时间、最大拉伸阻力、拉伸面积的直接增强效应和综合增强效应均较大;沉降指数对稳定时间和最大拉伸阻力、拉伸面积的直接增强和综合增强效应较大;所测蛋白质理化特性中未发现对拉伸长度有增强效应的指标。结论面粉中谷蛋白大聚体含量和沉降指数是对面团形成时间、稳定时间、拉伸阻力影响较大的因素,影响为正效应,可为专用面粉生产质量控制提供参考。     

Pulsed field gel electrophoresis (PFGE) analysis for multidrug resistant Salmonella enterica serovar Schwarzengrund isolates collected in six years (2000-2005) from retail chicken meat in Taiwan

Salmonella Schwarzengrund is one of the causative agents of human salmonellosis and animal infections. High prevalence of multidrug resistant strains of S. Schwarzengrund from chicken meat has been recently reported in Taiwan. With an attempt to see if such prevalence in chicken meat was due to the recirculation of S. Schwarzengrund strains in traditional marketplaces, a total of 173 S. Schwarzengrund strains isolated between 2000 and 2005 from 417 retail chicken meat samples purchased from Taipei, Taiwan were analyzed using pulsed field gel electrophoresis (PFGE) method. For XbaI and AvrII digested DNA, a total of 23 and 16 PFGE patterns, respectively, were obtained. When these patterns were combined, a total of 47 subtypes were obtained and the major subtypes were X3A2, X1A2 and X2A1. Since it was found that these major subtypes were repeatedly found for multidrug resistant strains collected from 2000 to 2005, we then collected the chicken meat isolates from central and southern Taiwan in 2006. These strains did not show similar major subtypes as those found in Taipei. Such results might also suggest that the repeated appearance of some major subtypes for S. Schwarzengrund strains isolated each year in Taipei was due to the recirculation of these strains in retail marketplace during these years.     

Improved Electrical Performance and Reliability of Poly-Si TFTs Fabricated by Drive-In Nickel-Induced Crystallization with Chemical Oxide Layer

Ni-metal-induced crystallization (MIC) of amorphous Si (α-Si) has been employed to fabricate low-temperature polycrystalline silicon thin-film transistors (TFTs). However, the Ni residues degrade the device performance. In this study, a new method for manufacturing MIC–TFTs using drive-in Ni-induced crystallization with a chemical oxide layer (DICC) is proposed. Compared with that of MIC–TFTs, the on/off current ratio (I _on/I _off) of DICC–TFTs was increased by a factor of 9.7 from 9.21 × 10⁴ to 8.94 × 10⁵. The leakage current (I _off) of DICC–TFTs was 4.06 pA/μm, which was much lower than that of the MIC–TFTs (19.20 pA/μm). DICC–TFTs also possess high immunity against hot-carrier stress and thereby exhibit good reliability.     

轮手一体机器人能量次优重构规划方法

模块化机器人的重构规划中,由于各模块的目标分配与其轨迹规划之间的耦合关系导致组合爆炸问题.本文提出一种基于简化模型的能量次优规划方法,将重构规划问题转化为最优控制问题,实现目标分配与轨迹规划的解耦.通过求解由Hamilton-Jacobi-Bellman（HJB）方程描述的最优控制问题,得到简化模型的值函数和最优轨迹.各模块的运动目标由值函数的吸引域决定.通过在最优轨迹附近的次优区域内搜索得到实际运动轨迹,提高了搜索效率.仿真实验结果表明,该方法能够选择合适的模块组合,并能在障碍物环境中生成满足机器人动力学约束的运动轨迹.