Detection of subsurface defects of fused silica optics by confocal scattering microscopy

<正>A non-destructive technique for subsurface measurements is proposed by combining light scattering method with laser confocal scanning tomography.The depth and distribution of subsurface defect layers are represented in term of scattered light intensity pattern,and three types of fused silica specimens are fabricated by different grinding and polishing processes to verify the validity and effectiveness.By using the direct measurement method with such technique,micron-scale cracks and scratches can be easily distinguished,and the instructional subsurface defect depths of 55,15,and 4μm are given in real time allowing for an in-process observation and detection.     

一种改进的SUSAN角点提取方法

针对基本SUSAN算法存在漏检测、处理速度慢以及容易产生伪角点等问题,提出了一种改进的SUSAN角点提取算法。首先对图像的像素点按边缘点、内部点和背景点进行分类,在此基础上只对边缘点进行SUSAN算法处理,然后检查已经提取到的所有角点,剔除同一区域范围内的伪角点,从而实现对大部分角点的快速、准确提取。实验结果表明,该算法的运算速度比改进前提高约一倍,能够较准确地检测到目标角点。     

Circulation times of hepatocellular carcinoma cells by in vivo flow cytometry

Hepatocellular carcinoma （HCC） may metastasize to many organs. The survival rate is almost zero for metastatic HCC patients. Molecular mechanisms of HCC metastasis need to be understood better and new therapies must be developed. We have developed the ＂in vivo microscopy＂ to study the mechanisms that govern liver tumor cells spreading through the microenvironment in vivo. A recently developed ＂in vivo flow cytometer＂ combined with real-time confocal fluorescence imaging is used to assess spreading and the circulation kinetics of liver tumor cells. We measure the depletion kinetics of two related human HCC cell lines, high-metastatic HCCLM3 cells and low-metastatic HepG2 cells, which are from the same origin and obtained by repetitive screenings in mice. More than 60% of the HCCLM3 cells are depleted within the first hour. Interestingly, the low-metastatic HepG2 cells possess noticeably slower depletion kinetics. In comparison, less than 40% of the HepG2 cells are depleted within the first hour. The differences in depletion kinetics might provide insights into early metastasis processes.     

Design and fabrication of automated sedimentation-based separation and siphon-based extraction for detection of allergic reaction on a centrifugal microfluidic disc

We report the design and fabrication of a novel and fully integrated polymer-based centrifugal microfluidic disc for rapid automatic allergens detection. All essential steps for a single test including flow valving, sequencing, mixing, separation, extraction, and sedimentation for final detection are automatically conducted within 30 min on a centrifugal microfluidic disc. Our design features a siphon-based valving and analyte extraction structure where the released analyte is separated and subsequently extracted by a siphon valve into the detection chamber. Incorporating the siphon valve and a series of capillary valves, we realize automated detection of allergic reaction on a centrifugal microfluidic disc.     

2-羟基-1-萘醛缩2-氨基-4-硝基苯酚亚胺的合成及其阴离子识别性能

以2-羟基-1-萘醛和2-氨基-4-硝基苯酚为原料,通过缩合反应合成了阴离子识别受体2-羟基-1-萘醛缩2-氨基-4-硝基苯酚亚胺（R）,其结构经¹H NMR, ¹³C NMR和IR表征。采用UV-Vis和¹H NMR等研究了受体R对阴离子的识别性能。结果表明：受体R在乙腈中对F^-、 H₂PO₄^-和AcO^-表现出良好的UV0Vis识别能力,且对上述阴离子表现出裸眼识别性能。通过核磁滴定、紫外滴定、络合常数及Job曲线等对受体R的识别机理进行了研究。结果表明：受体R与阴离子通过分子间氢键结合形成主客体配合物,对F^-具有更好的结合能力（络合常数为2.503 × 10⁴ L/mol）,与阴离子以比例1/1相互结合。     

Excitation and propagation of axisymmetric longitudinal guided waves in pipes immersed in infinite liquid media

The transient elastodynamic responses of the vacuum-filled and liquid-filled pipes surrounded by infinite liquid to external axisymmetric forces are simulated by employing the acoustic-structural coupled finite element method. The time-frequency distributions of the transients waveforms are obtained by the short-time Fourier transform （STFT）. Then the influence of the distribution of the external forces on the excitation of the guided waves is analyzed. The study shows that the L（O, 2） mode in the vacuum-filled pipe surrounded by the liquid is suitable for the pipe inspection because it is the fastest mode in a weakly dispersive and at- tenuative region of frequency. And it can be excited with high efficiency in the above region of frequency if the axisymmetric external force is applied on the inner or outer surface of the pipe axially. Analogously, the L（0,3） and L（0,4） modes in the liquid-filled pipe surrounded by the liquid are suitable for the pipe inspection.     

Employing a Cerenkov detector for the thickness measurement of X-rays in a scattering background

The variation in environmental scattering background is a major source of systematic errors in X- ray inspection and measurement systems. As the energy of these photons consisting of environmental scattering background is much lower generally, the Cerenkov detectors having the detection threshold are likely insensitive to them and able to exclude their influence. A thickness measurement experiment is designed to verify the idea by employing a Cerenkov detector and an ionizing chamber for comparison. Furthermore, it is also found that the application of the Cerenkov detectors is helpful to exclude another systematic error from the variation of low energy components in the spectrum incident on the detector volume.     

Rb与H_2的反应碰撞:Rb(6~2D)+H_2→RbH+H

在样品池条件下,应用脉冲激光的泵浦-检测技术,研究了Rb(6~2D)激发态原子与H_2反应碰撞生成的RbH分子的振转能级的布居数密度分布及平均转动能、振动能、平动能的相对比值.发现RbH(X~1∑~+)只有v=0,1上有布居.转动带分布轮廓与池温下的统计分布接近,得到RbH的Boltzmann转动温度稍低于池温,而振动温度高.v=1和v=0上的布居数之比约为0.69,从而得到RbH(X~1∑~+)上平均转动能和平均振动能,由反应的有效能得到平均平动能,这三种能量的相对比值f_R:f_V:     

用近红外无损肌氧及运动心率检测技术评定100m极量强度运动对心脏冲击影响

利用连续双波长近红外光技术测量肌肉中血红蛋白含氧量的变化情况,同时应用运动心率无线实时采集设备,设计了检测实时肌肉组织血氧含量和瞬时心率实验方案,对6名健康男性进行了100 m跑同步实测实验。实验表明,肌肉组织氧合血红蛋白浓度在100 m跑结束后继续降低,达到最低值的时刻滞后于运动结束时刻的时间为(6.65±1.10)s;心率则在运动结束后继续上升,达到最高值的时刻滞后于运动结束时刻的时间为(8.00±1.57)s。这些结果显示了双波长近红外光组织氧测试技术和运动心率无线实时采集系统能够正确检测极量强度运动时的血氧参数和心率,揭示了极量强度运动过程中肌肉中氧运输与消耗的过程及其与心率之间的动力学特征。     

试纸检测食物有害残留 几分钟出结果

可视化快速检测试纸的问世突破了制约食品安全监管能力的技术瓶颈,降低了检测成本,使监管从事后处理变为现场反应。