外腔半导体激光器的场功率谱和线宽

本文采用低频近似的方法,用半经典理论,给出了外腔半导体激光器的场功率谱和线宽公式,理论分析与实验结果是吻合的。     

外加酶法酿制低糖啤酒糖化工艺的研究

以普鲁兰酶Ｐｒｏｍｏｚｙｍｅ１２０Ｌ为重点，综合分析了外加酶糖化过程中影响麦汁总还原糖量和糖组成的各种因素，如各酶制剂的用量、糖化温度、料水比、物料比及各因素之间的相互作用等，确定了一套最优的糖化工艺方案。所得麦芽汁浸出率高、色度浅、粘度低、还原糖含量高；经过高效液相色谱分析（ＨＰＬＣ）表明，其糖组成合理；经过十天的发酵，发酵度达８２．２％，酒精分为６．４５５％（Ｗ／Ｗ）。     

Quality evaluation of pickling cucumbers using hyperspectral reflectance and transmittance imaging: Part I. Development of a prototype

This article reports on the development of a hyperspectral imaging prototype for online evaluation of external and internal quality of pickling cucumbers. The prototype consisted of a two-lane round belt conveyor, two illumination sources (one for reflectance and one for transmittance), and a hyperspectral imaging unit. It had a novel feature of simultaneous imaging under reflectance mode in the visible region (400–675 nm) and transmittance mode for the red and near-infrared region (Red-NIR) (675–1000 nm). Reflectance information from the visible region was intended for evaluating the external characteristics of cucumbers such as skin color, whereas transmittance information from Red-NIR was used for internal defect detection (i.e., hollow center). Additional features of the prototype included simultaneous acquisition of reflectance and transmittance from calibration references that were installed in the system, to provide real-time, continuous corrections of individual hyperspectral images from each sample. Methods and algorithms were developed of estimating cucumber fruit size and correcting the effect of fruit size on transmittance measurements. The system was calibrated and evaluated for detecting the color, size, and internal defect of pickling cucumbers.     

烟用香精中薄荷醇的气相色谱/质谱分析

采用保留时间比对法和选择离子(81amu)气相色谱/质谱法定性定量分析了烟用香精中的薄荷醇.方法的检测限为0.0028mg/mL,平均回收率为98.52%,RSD为2.41%.     

陶瓷样品外束质子荧光定量分析中样品定位精度的研究

通过改变与陶瓷有相似成份的GBW07306水系沉积物标准样品的前后位置和角度,研究了陶瓷样品外束质子荧光(External beam proton induced X-ray emission,外束PIXE)分析中样品位置对测量结果的影响.并以此为依据分析了陶瓷样品外束PIXE定量分析对样品定位精度的要求.结果表明:在质子能量为2.5MeV、样品距离质子引出窗口12mm和质子束入射方向夹角为30°、Si(Li)探测器在80°且距离样品20mm的实验条件下,沿束流方向位置变化引起的相对误差控制在5%以内时,样品定位精确度应高于±0.14mm;样品与质子束夹角变化引起的相对误差控制在5%以内时,样品角度定位需精确到±1.2°.     

Wind effects on flame projection probability from a compartment with opposing openings

This paper investigates flame projection probability from a compartment with opposing openings under assisting wind environment. The effect of external wind on the flow conditions at the door, hot gas velocity at the window and flame projection probability was investigated. Results showed that when the external wind is absent or at low wind velocities, bidirectional flow can be seen at the door. With the increment of the wind velocity, the bidirectional flow will become unidirectional at low fuel supply rate. At high wind velocities, the unidirectional flow can be seen at the door regardless of the fuel supply rate. Correlations for hot gas velocity at the window are formulated based on the mass conservation of the flow in the compartment. The calculated results have a good agreement with the experimental data. Due to fluctuations of the gases ejected from the window, flames eject from the compartment intermittently. The intermittent characteristic of flame ejecting from the compartment is influenced by the temperature and velocity of the hot gas velocity at the window. The model to predict flame projection probability is modified based on previous study without external wind.     

PIXE analysis and fission track dating of obsidian from South American prehispanic cultures (Colombia, Ecuador)

In the present work we have coupled PIXE with fission track dating to characterise obsidian artefacts from about 40 archaeological sites of Colombia and Ecuador. PIXE analysis, carried out with the external beam line of the AGLAE tandem accelerator, yields the content in about 15 elements with Z > 8, whereas fission track dating is applied to ages in excess of about 10 000 years. About 120 artefacts were investigated by PIXE, of which 50 were dated by fission tracks. Ages and compositions were compared to those of obsidians from all known geological sources of the region. We show that this double characterisation allows us to determine the number of obsidian sources exploited in an ancient past and to give some insight into obsidian circulation.     

浅析油田外部市场廉洁风险的有效防控

以规范权力运行和监督为主线,对油田外部市场廉洁风险防控情况进行研究,有针对性地制定和实施预警预防、制度规范、监督制约等防控措施,可以规范油田外部市场,廉洁从业环境,促进企业健康有效对外发展。     

浅谈小高层外墙渗水及封堵

在剪筒结构中,模板加固大量使用对拉螺杆,优点是加快了工期,节约了成本,但外墙的螺杆洞和外窗四周渗漏一直是质量通病。经查阅资料,结合现场施工,对外墙螺杆洞和窗四周的封堵防水提出了有效地修补方法。     

外腐蚀管道剩余寿命的有限元分析

预测油气管道的剩余寿命, 对避免管道泄漏事故的发生和节省维修费用具有重要意义。针对国内某成品油管道开挖点处的两个腐蚀缺陷, 基于有限元分析方法, 建立了管道椭球形缺陷的三维有限元结构模型。以管道实测缺陷尺寸为依据, 在已知腐蚀速率的情况下, 采用非线性分析技术对腐蚀管道进行了应力分析, 依据塑性极 限状态失效准则预测了管道的剩余寿命。结果表明, 两个腐蚀缺陷的剩余寿命分别为8a和1 3a, 预测结果可为管道的维护维修提供理论依据。