Phase transition and near-zero thermal expansion of Zr_(0.5)Hf_(0.5)VPO_7

The Zr_(0.5)Hf_(0.5)VPO_7 is successfully synthesized by the solid-state method with near-zero thermal expansion. Powder x-ray diffraction(XRD), Raman spectroscopy, thermal dilatometry, and scanning electron microscopy(SEM) are used to investigate the structure, the phase transition, and the coefficient of thermal expansion(CTE) of Zr_(0.5)Hf_(0.5)VPO_7. The investigation results show that the samples are of the single cubic type with a space group of Pa3ˉ at room temperature(RT).It can be inferred that the superstructure is transformed from the 3 × 3 × 3 superstructure to the 1 × 1 × 1 ideal crystal in a temperature range between 310 K and 323 K. The CTE is measured by a dilatometer to be 0.59 × 10~(-6) K~(-1)(310 K–673 K). The values of intrinsic(XRD) and extrinsic(dilatometric) thermal expansion are both near zero. The results show that Zr_(0.5)Hf_(0.5)VPO_7 has near-zero thermal expansion behavior over a wide temperature range.     

Determination of 12 additives in beverages by evaporation-assisted dispersive liquid-liquid microextraction based on the solidification of floating organic droplets combined with liquid chromatographyEI北大核心CSCD

An analytical method for the simultaneous determination of 12 additives in beverages was developed using evaporation-assisted dispersive liquid-liquid microextraction based on the solidification of floating organic droplets EVA-DLLME-SFOcombined with high performance liquid chromatography HPLC. The samples were extracted twice with 70%V/Vmethanol aqueous solution and extracted by EVA-DLLME-SFO method after the combination of the extractsand finally determined by HPLC. Extraction parameterssuch as types and amounts of extractantevaporant and heating agentthe concentration of saltand the extraction time were optimized. Under the optimized conditionsthere were good relationships in the ange of 0.25-50 μµg/mL with the limits of detection of 1.5 to 13.6 mg/kg and limits of quantification of 5.2 to 45.3 mg/kg. The recoveries at three spiked levels1025 and 50 mg/kgwere 76.8% to 101.2% with the relative standard deviations of 0.11% to 4.7%. The method can be used for rapid detection of 12 additives in beverages. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

基于芬顿反应和硫磺素T构建免标记荧光传感器用于葡萄糖的检测

基于芬顿反应和硫磺素T(ThT)构建新奇的免标记荧光传感器用于葡萄糖的检测。当无葡萄糖存在时,ThT诱导富G-DNA探针形成G-四链体/ThT复合物,ThT的荧光强度显著增强;当葡萄糖存在时,葡萄糖氧化酶催化葡萄糖产生H2 O2,在Fe^2+催化的芬顿反应作用下,H2 O2转化为羟基自由基(·OH),·OH引发DNA的氧化损伤导致富G-DNA探针裂解为短寡核苷酸片段而丧失形成G-四链体/ThT的能力,ThT的荧光强度显著降低,从而实现对葡萄糖的检测。在优化的检测条件下,G-四链体/ThT荧光强度变化和葡萄糖浓度在0.5~45μmol/L的范围内呈现较好的线性关系(R^2=0.99268),检出限为0.1μmol/L。利用本法对葡萄糖加标的血液样品进行分析,葡萄糖的回收率为90.7%~118.3%,相对标准偏差为1.7%~5.8%,方法可用于血糖检测。     

膜载体酶标记dip-stick快速检测西维因的痕量残留

利用直接竞争酶联免疫吸附分析技术研发了一种快速、灵敏的膜载体酶标记dip-stick农残西维因检测方法。该方法以带正电尼龙膜(Millipore)为固相载体,将西维因抗体包被于膜上,包被有抗体的膜插入含有西维因和西维因酶标抗原的混合液中竞争反应10 min后直接目视判断分析结果。该方法的整个检测过程只需15 min,对西维因的检出限可达到10μg.L-1,且稳定性较好。通过与高效液相色谱法(HPLC)比较,验证了该检测方法的有效性,可作为品质控制和快速定性检测的一种有效工具。     

激光快速烧结合成HfW_2O_8及其特性的研究

采用激光烧结的方法快速合成HfW2O8陶瓷,X射线衍射(XRD)和拉曼光谱分析表明,合成物的主要成分是立方相的HfW2O8含有极少量的正交相,这是由于样品在凝固的过程中温度从熔池到周围环境迅速降低会产生较大的压应力,压应力约在0.6GPa左右。扫描电镜(SEM)观察表明,晶粒沿激光扫描的方向取向生长,形貌为柱状晶,排列错落有致,均匀致密,晶粒内少有气孔,尺寸在几10μm左右。     

Open critical area model and extraction algorithm based on the net flow-axis

In the integrated circuit manufacturing process, the critical area extraction is a bottleneck to the layout optimization and the integrated circuit yield estimation. In this paper, we study the problem that the missing material defects may result in the open circuit fault. Combining the mathematical morphology theory, we present a new computation model and a novel extraction algorithm for the open critical area based on the net flow-axis. Firstly, we find the net flow-axis for different nets. Then, the net flow-edges based on the net flow-axis are obtained. Finally, we can extract the open critical area by the mathematical morphology. Compared with the existing methods, the nets need not to divide into the horizontal nets and the vertical nets, and the experimental results show that our model and algorithm can accurately extract the size of the open critical area and obtain the location information of the open circuit critical area.     

图空间上自适应形态学算子

为了解决现有图空间上形态学应用中固定选取结构元素的问题,在图空间上提出了相似权的概念,定义了自适应结构图,对结构图的性质进行了证明.在此基础上提出一种图空间上自适应形态学算子,并从理论上验证了该算子的完备性.新算子不仅考虑了图像像素点的局部特征,同时考虑了连续像素的全局特征.实验结果表明,新算子不仅在保存彩色信息的完整及关联性方面优于现有的彩色形态学,而且可以根据图像的特征自适应的选取阈值和结构元素,在更精细的图像处理方面具有良好的应用前景.     

转型背景下地方高校光电类专业实践教学体系构建

在应用技术型人才培养中, 实践教学体系直接决定了应用型人才培养的质量和水平, 在地方高校的转 型背景下, 分析了光电信息科学与工程专业实践教学体系的构建原则, 构建了“ 五大体系、 三大层次、 七大模块、 三大 平台”的层次化、 模块化光电信息科学与工程专业实践教学体系, 明确了实践教学体系的中各环节的目标与内容, 进一步实现专业建设与行业标准的融合, 学历教育与岗位技能的对接     

激光快速烧结合成A(WO4)2(A=Zr2+,Hf2+)的特性研究

利用二氧化碳激光快速凝固技术合成了负热膨胀材料ZrW2O8和HfW2 O8,Raman光谱和X射线衍射分析表明激光烧结合成的ZrW2 O8为正交相,压应力的大小估计在0.4～0.5 GPa之间,激光烧结合成的HfW2 O8,主要为立方晶系,含有极少量的正交系,压应力的大小估计在0.6 GPa左右,这是由于样品在快速凝固的过程中受到了压应力造成的.由于压应力的影响,二氧化碳激光快速凝固技术更适合HfW2O8的制备和合成.     

基于线性规划的关键面积最小化方法

随着集成电路(IC)技术的不断发展,尤其在90nm和65 nm技术节点,集成电路制造业的投资剧增而随机成品率却在下降.为了提升随机成品率,需要在布线或后布线阶段减小关键面积.文中提出一种基于线性规划降低关键面积的方法,使关键面积在一组条件约束下,通过版图中一些特征量的变化,建立起一个线性规划模型,然后求其最优解,进而得出关键面积的最小值.该方法的优点是把一个版图优化问题转化为数学问题,使问题更精确化,从而为成品率的优化提供了一条新途径.