Electrospun fiber membranes from blends of poly(vinylidene fluoride) with fouling‐resistant zwitterionic copolymers

Nonwoven super‐hydrophobic fiber membranes have potential applications in oil–water separation and membrane distillation, but fouling negatively impacts both applications. Membranes were prepared from blends comprising poly(vinylidene fluoride) (PVDF) and random zwitterionic copolymers of poly(methyl methacrylate) (PMMA) with sulfobetaine methacrylate (SBMA) or with sulfobetaine‐2‐vinylpyridine (SB2VP). PVDF imparts mechanical strength to the membrane, while the copolymers enhance fouling resistance. Blend composition was varied by controlling the PVDF‐to‐copolymer ratio. Nonwoven fiber membranes were obtained by electrospinning solutions of PVDF and the copolymers in a mixed solvent of N,N‐dimethylacetamide and acetone. The PVDF crystal phases and crystallinities of the blends were studied using wide‐angle X‐ray diffraction and differential scanning calorimetry (DSC). PVDF crystallized preferentially into its polar β‐phase, though its degree of crystallinity was reduced with increased addition of the random copolymers. Thermogravimetry (TG) showed that the degradation temperatures varied systematically with blend composition. PVDF blends with either copolymer showed significant increase of fouling resistance. Membranes prepared from blends containing 10% P(MMA‐ran‐SB2VP) had the highest fouling resistance, with a fivefold decrease in protein adsorption on the surface, compared to homopolymer PVDF. They also exhibited higher pure water flux, and better oil removal in oil–water separation experiments. © 2018 Society of Chemical Industry     

High-efficiency Silicon Solar Cells: A Review

Over the past few decades, crystalline silicon solar cells have been extensively studied due to their high efficiency, high reliability, and low cost. In addition, these types of cells lead the industry and account for more than half of the market. For the foreseeable future, Si will still be a critical material for photovoltaic devices in the solar cell industry. In this paper, we discuss key issues, cell concepts, and the status of recent high-efficiency crystalline silicon solar cells.     

Development of a safety critical software requirements verification method with combined CPN and PVS: a nuclear power plant protection system application

Safety-critical software systems such as certain nuclear instrumentation and control (NI&C) systems should be developed with thorough verification. This study presents a method of software requirement verification with a case study for a nuclear power plant (NPP) protection system. The verification introduces colored petri net (CPN) for system modeling and prototype verification system (PVS) for mathematical verification. In order to aid flow-through from modeling by CPN to mathematical proof by PVS, an information extractor from CPN models has been developed in this paper. In order to convert the extracted information to the PVS specification language, a translator has also been developed. This combined method has been applied to the functional requirements of the Wolsong NPP Shut Down System #2 (SDS2); logical properties of the requirements were verified. Through this research, guidelines and a tool support for the use of formal methods have been developed for application to NI&C software verification.     

Purification and characterization of a human bradykinin binding protein from inflammatory cells

Bradykinin (BK) is a potent mediator with a broad spectrum of pharmacological and inflammatory actions which are exerted through cell surface receptors. We report here the affinity chromatographic purification of a novel 14 kDa BK binding protein from human blood neutrophils and also peripheral blood mononuclear cells (PBMC), 80% of which are lymphocytes. Radioreceptor crosslinking experiments using bifunctional crosslinkers and radiolabelled BK identified a 14 kDa protein in these cell types both on the cell surface, in glycerol purified plasma membranes and in detergent solubilized cell extracts. Purification by BK affinity chromatography from a variety of BK responsive human cell types i.e. CCD-16Lu lung fibroblasts, HL60 promyelocytes, U937 myelomonocytes and Jurkat T lymphocytes also demonstrated a 14 kDa protein. Purified material obtained from three different BK affinity columns all demonstrated three major proteins at 190, 50 and 14 kDa when eluted with either excess BK or mild acid. Neutrophil fractions from detergent solubilized cell extracts contained an additional 150 kDa protein when eluted with mild acid. Neutrophil and PBMC crude plasma membrane BK affinity column purifications yielded only a single 14 kDa protein. Radioreceptor dot assays of the purified neutrophil eluates containing the 14 kDa protein revealed specific binding to [125I]-BK with a 160 fold excess signal ratio over the original membrane extract. Our data indicates that we have successfully isolated a 14 kDa novel human BK specific binding protein expressed on the surface of inflammatory cells.     

Acute aortic outflow obstruction by diminution of bulboventricular foramen size after volume unloading in univentricular physiology

A young child with [S, L, L] segmental anatomy, double-inlet left ventricle, transposition of the great arteries, rudimentary right ventricle, and mildly restrictive bulboventricular foramen is reported, in whom intraoperative temporary snaring of the modified Blalock-Taussig shunt resulted in instantaneous and dramatic volume contraction of the left ventricle, decrease in bulboventricular foramen size, and increase of the gradient across the latter from 10 mm Hg preoperatively to 50 mm Hg. A modified Damus-Stansel-Kaye procedure using autogenous aortic tissue resulted in unobstructed aortic outflow; in addition, a bidirectional cavopulmonary shunt was performed. The importance of early relief of actual or potential aortic outflow obstruction in hearts with restrictive bulboventricular foramen is emphasized.     

A novel dynamic survivable routing in WDM optical networks with/without sparse wavelength conversion

In this paper, we study the dynamic survivable routing problem, both in optical networks without wavelength conversion and in optical networks with sparse wavelength conversion, and propose a novel hybrid algorithm for it based on the combination of mobile agents technique and genetic algorithms (GA). By keeping a suitable number of mobile agents in the network to cooperatively explore the network states and continuously report cycles (that are formed by two disjoint-link routes) into the routing tables, our new hybrid algorithm can promptly determine the first population of cycles for a new request based on the routing table of its source node, without the time consuming process associated with current GA-based lightpath protection schemes. We further improve the performance of our algorithm by introducing a more advanced fitness function that is suitable for both the above networks. Extensive simulation studies on the ns-2 network simulator show that our hybrid algorithm achieves a significantly lower blocking probability than the conventional survivable routing algorithms for all the cases we studied.     

高频超声波在氧化皮中传播性能标定

对高频超声小在12Cr2MoWVTiB(G102钢）和12Cr1MoV钢钢管运行所产生氧化皮中的传播速度进行了定量标定，并对标定误差进行了统计计算，结果表明，12Cr1MoV钢氧化皮测厚标定点最大偶然误差值为0．050mm,G102钢为0．030mm，并指明了误差来源。     

海洋石油平台水下夹桩器本体结构分析

水下夹桩器是一种广泛应用于海洋石油平台建设的液压夹具。水下夹桩器本体焊接在导管架上，支撑夹桩器液压缸。在水下夹桩器本体设计中，采用有限元法完成了对本体强度和刚度的结构分析；建立了有限元分析模型，用ANSYS软件进行结构分析，得到了分析结果，并将该结果与理论计算结果进行了比较，验证了有限元分析技术的有效性。设计结果满足工程要求，为改进和优化结构提供了理论依据，节省了分析计算时间。     

Satellite SAR Remote Sensing of Great Lakes Ice Cover,Part 2. Ice Classification and Mapping

During the 1997 winter season, shipborne polarimetric backscatter measurements of Great Lakes (freshwater) ice types using the Jet Propulsion Laboratory C-band scatterometer, together with surface-based ice physical characterization measurements and environmental parameters, were acquired concurrently with Earth Resource Satellite 2 (ERS-2) and RADARSAT Synthetic Aperture Radar (SAR) data. This polarimetric data set, composed of over 20 variations of different ice types measured at incident angles from 0° to 60° for all polarizations, was processed to radar cross-section to establish a library of signatures (look-up table) for different ice types. The library is used in the computer classification of calibrated satellite SAR data. Computer analysis of ERS-2 and RADARSAT ScanSAR images of Great Lakes ice cover using a supervised classification technique indicates that different ice types in the ice cover can be identified and mapped, and that wind speed and direction can have an influence on the classification of water as ice based on single frequency, single polarization data. Once satellite SAR data are classified into ice types, the ice map provides important and necessary input for environmental protection and management, ice control and ice breaking operations, and ice forecasting and modeling efforts.