传感器可靠性筛选方法的研究

本文通过对力、压力、热、磁等多种传感器的研究及试验找到了一些比较可行的传感器可靠性筛选方法。     

Lipophilic organic contaminants in the Rhine river, Germany

Detailed gas chromatographic-mass spectrometric analyses applied to eight Rhine river water samples constituted a comprehensive characterization of the low molecular weight organic contamination. Within the group of predominant anthropogenic contaminants, only a few compounds were characterized as frequently detected or priority pollutants. Numerous compounds exhibiting physiological or ecotoxicological properties are only rarely reported or still unnoticed riverine contaminants. Information on environmental behaviour or ecotoxicological effects is still limited for most of these substances. In particular, several brominated compounds (mono- and dibrominated (methoxyphenyl)propionic acids and hydroxymethylacetophenones) were identified for the first time as environmental contaminants. Quantitative analyses differentiated five groups of pollutants with respect to their concentration profiles. The spatial distribution and the intensity of emission sources on the one hand and the environmental stability as well as the tendency to adsorb on the particulate matter on the other hand determined the quantitative occurrence of individual compounds.     

国内筛分设备的现状和展望

介绍了我国筛分设备的发展概况、筛分机械行业现状及存在的问题,并提出了发展方向。     

不同保鲜方式下鲜食玉米品质变化规律的研究

目的 探索不同贮藏方式下鲜食玉米各品质指标的变化规律。方法 针对不同类型鲜食玉米（甜玉米、糯玉米和甜糯玉米）,选取常温（25℃）、保鲜温度（4℃）2种温度下真空包装（蒸煮、非蒸熟）、普通保鲜袋、特制袋子、仪器等不同处理,通过试剂盒测定不同处理下氨基酸、淀粉、糖类的变化趋势和规律。结果 甜玉米蒸煮后氨基酸含量更高,而糯玉米和甜糯玉米蒸煮后氨基酸含量降低;甜玉米蒸煮后可溶性糖和葡萄糖含量变高,糯玉米蒸煮后蔗糖含量变高,甜糯玉米蒸煮后果糖、葡萄糖和蔗糖含量变高;短期保鲜时,可以采用4℃真空和4℃特制袋子+保鲜剂+吸水纸两种处理,中长期保鲜时,可采用4℃蒸煮后进行真空保存,该方法优于非蒸煮。结论 甜玉米、糯玉米和甜糯玉米在不同保鲜时间、不同处理间各指标的变化趋势不同,4℃真空+保鲜剂+吸水纸和4℃特制袋子+保鲜剂这2种处理相比而言则起不到最优的作用,说明短期保存中,4℃真空已不需要额外添加保鲜剂,而4℃特制袋子+保鲜剂处理中一定要添加吸水纸,否则保鲜效果将变差。     

Visual acuity and contrast sensitivity screening with a new iPad application

We present a new iPad application (app) for a fast assessment of Visual Acuity (VA) and Contrast Sensitivity (CS) whose reliability and agreement was evaluated versus a commercial screening device (Optec 6500). The measurement of VA was programmed in the app in accordance with the Amblyopia Treatment Study protocol. The CS was measured with sinusoidal gratings of four different spatial frequencies: 3, 6, 12 and 18 cpd at the same contrast values of the Functional Acuity Contrast Test (FACT) included in the Optec 6500. Forty-five healthy subjects with monocular corrected visual acuities better than 0.2 logMAR participated in the agreement study. Bland-Altman analyses were performed to assess the agreement and Deming regressions to calculate Mean Differences (MDs) and Limits of Agreement (LoAs). Coefficients of reliability were 0.15 logMAR for our method and 0.17 logMAR for the ETDRS testing protocol. For testing the CS, our test showed no statistically significant differences compared with the FACT at any spatial frequency (p > 0.05). The MDs were lower than 0.05 log units for all spatial frequencies.     

A shortcut method for the preliminary synthesis of process-technology pathways: An optimization approach and application for the conceptual design of integrated biorefineries

Synthesis and screening of technology alternatives is a key process-development activity in the process industries. Recently, this has become particularly important for the conceptual design of biorefineries. This work introduces a shortcut method for the synthesis and screening of integrated biorefineries. A structural representation (referred to as the chemical species/conversion operator) is introduced. It is used to track individual chemicals while allowing for the processing of multiple chemicals in processing technologies. The representation is used to embed potential configurations of interest. An optimization approach is developed to screen and determine optimum network configurations for various technology pathways using simple data. The solution to the optimization formulation provides a quick and effective method for screening and interconnecting the technological pathways and to distributing the flows over the network. Case studies are solved to illustrate the applicability of the proposed approach.     

Detectability of corrosion damage with circumferential guided waves in reflection and transmission

There is an increasing interest in high frequency short range guided waves to screen or monitor for corrosion. This contrasts with long range guided waves (LRGWs) which screen pipes for large patches of corrosion and have been successfully used in corrosion management for the past twenty years. The fundamental setup described in this paper uses circumferential guided waves, which are excited at a single location on a pipe and travel around the pipe wall and are detected at the same location. The study uses a finite element model assisted method to evaluate the detection capability of two short range circumferential guided wave setups which use both the reflected and transmitted signals. The setups themselves consist of either an axial array of transducers, for monitoring, or a single transducer which axially scans a pipe. Both setups have an array or scan pitch between either adjacent transducers or measurements. The detection capability of the fundamental Lamb wave modes (A0 and S0) in both reflection and transmission have been compared, as well as a hybrid shear horizontal wave setup, which uses the SH0 mode in reflection and the SH1 mode in transmission. A sensitivity analysis was conducted using two separate methods to determine the probability of detection (POD) for either the reflection or transmission signals. Both methods determine a POD for a specific defect, noise level, and array or scan pitch. Probability images are produced which map the POD for a range of defect sizes. For the parameters investigated in this study, it was found that in transmission large diameter defects have a higher detectability, whereas deep, narrow diameter defects are more detectable in reflection. A generalised overview of the sensitivity of short range guided waves is presented by combining both the reflection and transmission PODs. The data fused sensitivity of the S0 and SH hybrid modes are given as 0.6% and 0.75% cross sectional area (CSA) respectively, allowing for the comparison with LRGWs. The A0 mode was excluded from the POD analysis because it was much less sensitive than the other two modes.     

RetCam Ⅲ视网膜成像系统在早产儿视网膜病变筛查中的临床应用

目的通过视网膜筛查了解RetCamⅢ在早产儿视网膜病变筛查工作中的应用情况。方法应用RetCamⅢ视网膜广角成像系统对入选患儿进行视网膜筛查。结果在筛查的174例小儿中,发现早产儿视网膜病变31例以及先天性白内障2例,视网膜出血4例,视网膜渗出7例。结论 RetCamⅢ能够安全有效地应用于早产儿视网膜筛查及先天性眼疾的临床筛查,有利于小儿眼病的早发现、早诊断、早治疗。     

New model of screening kinetics

An understanding of screening requires a knowledge of screening kinetics. The new model of screening kinetics presented in this paper is theoretically described and experimentally proven. Samples of different raw materials, different in their density, bulk density, particle size distribution and particle shape, were used.The conducted experiments confirmed that the new model of screening kinetics successfully describes the process of screening of various raw materials even when they are exposed to a range of factors that most influence the screening process (dimensions of the screen, particle size distribution of raw materials, particle shape, and thickness of the bed on the screen).The advantage of this model of screening kinetics lies in its simplicity as it is characterized by the fact that it has only one parameter, i.e., (k) - the screening rate constant, which is experimentally measured. This constant can be measured on the basis of a single screening experiment. This fact is very significant for practical applications of the model to an industrial screen.     

用边际分析理论评价老区增产措施

为了正确评价和筛选老油气区的增产措施，除了优选地质和油藏条件外，还应从经济角度加以论证，根据边际分析理论，提出了两种计算增产措施边际成本的方法，分别适合于实际资料丰富和缺乏的情况，并根据边际成本等于边际效益的原则，确定出老区增产措施的边际价格以及在现行价格体系下各项措施的取舍条件。由此，对增产措施进行评价，优选出地质及工艺上可行的、经济效益好的项目。实践证明，本方法是可行的。