3LPE防腐层国内及国际标准对比分析

为满足涉外工程需要,更好使用3LPE防腐层的国内外标准。采用对比的方式对3LPE防腐层的中国标准GB/T 23257-2009和国际标准ISO 21809-1∶2011在防腐层厚度、原材料性能指标、防腐层性能指标等方面逐一进行了分析。总体来说,GB/T 23257-2009对材料的性能要求更详细,对原材料供应商、涂敷厂的要求更严,利于涂层质量的控制,符合中国实情。对于涉外项目,要求执行ISO21809-1∶2011,但在中国进行生产的3LPE防腐层,需要特别注意ISO 21809-1∶2011与GB/T 23257-2009的差异性。     

3D modelling of coupled mass and heat transfer of a convection-oven roasting process

A 3D mathematical model of coupled heat and mass transfer describing oven roasting of meat has been developed from first principles. The proposed mechanism for the mass transfer of water is modified and based on a critical literature review of the effect of heat on meat. The model equations are based on a conservation of mass and energy, coupled through Darcy's equations of porous media — the water flow is mainly pressure-driven. The developed model together with theoretical and experimental assessments were used to explain the heat and water transport and the effect of the change in microstructure (permeability, water binding capacity and elastic modulus) that occur during the meat roasting process. The developed coupled partial differential equations were solved by using COMSOL Multiphysics®3.5 and state variables are predicted as functions of both position and time. The proposed mechanism was partially validated by experiments in a convection oven where temperatures were measured online.     

Van der Waals two-color infrared photodetector

With the increasing demand for multispectral information acquisition, infrared multispectral imaging technology that is inexpensive and can be miniaturized and ...     

Matting films prepared from waterborne acrylic/micro‐SiO2 blends

Acrylic resin/micro‐SiO₂/polymethyl urea (AC/SiO₂/PMU) composites were prepared by physical blends of acrylic resin latex (AC), polymethyl urea resin (PMU), and modified SiO₂. The effects of SiO₂ and PMU content in the hybrid composites morphology and physical properties were investigated in detail using transmission electron microscopy (TEM), UV‐Vis spectrometry (UV‐Vis), scanning electron microscope (SEM), thermogravimetric analysis (TGA), and contact angle measurement. The results showed that introduction of SiO₂ into AC composites could increase the viscosity which caused by gelation and agglomeration of SiO₂. The TEM, SEM images, and TGA results indicated that hybrid membranes have phase separation. During the film formation process, a high number of PMU and SiO₂ particles of an appropriate size were stranded on the surface of the film to form matting surface. These results highlight the sensitivity of the gloss to the polymer morphology and surface. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41707.     

天铁烧结技术改造及效益分析

天津铁厂烧结分厂近几年来通过强化管理和依靠技术进步，烧结矿产量连年大幅提高，促进了铁厂稳步发展。文章就几项技术改造做了介绍分析。     

Recovery of Salmonella, Listeria monocytogenes, and Mycobacterium bovis from cheese entering the United States through a noncommercial land port of entry

A joint multiagency project was initiated in response to a Salmonella outbreak in San Diego County, California, in 2004. Samples of cheese were collected during four 1-day operations at the San Ysidro port of entry, along the United States-Mexico border. Surveyed participants were persons crossing the border as pedestrians or in vehicles who had a minimum of 2.27 kg of cheese, which may suggest a potential diversion to illegal marketing. In addition, data were collected about the cheese to identify risk factors for cheese contamination. Two hundred four cheese samples were submitted to the California Animal Health and Food Safety Laboratory System-San Bernardino Branch and analyzed for potential food pathogens. Ninety-four percent (190 of 203) of the samples tested positive for alkaline phosphatase. Salmonella was detected from 13% (27 of 204) of the samples comprising 11 serogroups and 28 serotypes. Pulsed-field gel electrophoresis DNA fingerprinting analysis, performed following standardized methods, determined that an isolate obtained from this study had an indistinguishable pattern from a recent Salmonella enterica serovar Typhimurium var. Copenhagen epidemic in the San Diego County that was linked to 14 illnesses. Listeria spp. were detected from 4% (8 of 204) of the samples, and of these, half were identified as L. monocytogenes. Escherichia coli O157:H7 was not detected from any of the samples. Mycobacterium bovis was detected from one panela-style cheese sample. Nine additional samples yielded Mycobacterium spp.     

天然气处理厂接地材质选择探讨

合理选择接地材质是保障接地系统可靠性的关键因素,为了优化接地材质的选择,对比分析了钢、铜两种材质的接地性能以及对其它埋地金属管线的影响。在理论分析和实际案例的基础上,提出天然气处理厂内变电站接地系统采用铜接地、其它区域采用钢接地的优化措施。该方法能有效提高接地系统的可靠性,降低变电站接地电阻值,削弱接地材质对埋地金属管线的影响,具有良好的稳定性、经济性,可以广泛应用于天然气处理厂接地系统设计中。     

Preparation of novel reticulated prickly porous ceramics with mullite whiskers

Porous materials are widely used in heat exchangers, sewage treatment, electromagnetic shielding, thermal insulation, gas adsorption, photocatalytic due to their high specific surface area. The specific surface area of materials plays a pivotal role in them. It can be enhanced by increasing the porosity of the material, but the cost of this improvement is reducing the strength of the material. In order to improve performance, it is necessary to increase its surface area without reducing the strength of the material. In this work, mullite porous ceramics with mullite whisker on the inside and outside surfaces structures, which known as prickly porous ceramics(PPCs). They were fabricated using polyurethane foam coated with slurries as the pore-forming agents, sintered after secondary impregnation with silica sol and ammonium fluoroaluminate. The the sintering temperature as well as slurry composition of secondary impregnation were tuned to tailor the strength and surface structures of the PPCs. In addition, the potential of PPCs as high-temperature catalyst supports was demonstrated. Overall, the PPCs demonstrated large surface areas and high mechanical strength. This study paved the way for the fabrication of high-performance porous ceramics.     

低温等离子体协同铜铈催化剂脱除甲苯

以挥发性有机化合物（VOCs）中的代表物质甲苯作为脱除对象,采用柠檬酸水热法制得铜铈催化剂,考察了低温等离子体协同不同摩尔比铜铈催化剂脱除甲苯的性能。研究发现铜铈复合型金属催化剂可以大幅度提升低温等离子体对甲苯的脱除效率,降低初始浓度、气体流速和升高电压可以提高甲苯脱除效率。同时利用N₂吸附-脱附（BET）、X射线衍射（XRD）、X射线光电子能谱（XPS）、程序升温还原（H₂-TPR）、红外光谱（FTIR）等手段对催化剂进行表征,发现催化剂活性组分分布较均匀,铜铈复合型金属催化剂表面氧空位、吸附态氧含量高于单金属氧化物催化剂,这有利于催化剂活性氧的释放。铜铈之间存在着协同作用,铜铈之间的氧化还原循环有利于甲苯的氧化。     

水下目标声图像特征分析与二次处理

水声环境极其复杂,多途、混响等因素对水中传播的声信号造成的畸变,使得水下目标声成像的分辨率和清晰度受到很大影响。在总结水声目标声图像特征的基础上,深入开展了水声目标图像增强、图像处理的研究,主要内容包括:水声目标图像特征分析、目标图像的二次处理方法、图像处理仿真研究等内容。在图像增强处理的过程中,采用Sobel算子、Prewitt算子、LOG算子和Canny算子。仿真结果显示处理后的水声图像其轮廓比较清晰,图像质量得到了改善,为鱼雷通过图像识别目标要害部位并实施精确打击奠定了基础。