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Morphology and properties of biodegradable and biosourced polylactide blends with poly(3-hydroxybutyrate-co-4-hydroxybutyrate)

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POLYMER COMPOSITES 2012年第6期33卷 850-859页

作者： Han, Lijing Han, Changyu Zhang, Huiliang Chen, Shan Dong, Lisong Chinese Acad Sci Changchun Inst Appl Chem Key Lab Polymer Ecomat Changchun 130022 Peoples R China Chinese Acad Sci Grad Sch Beijing 10080 Peoples R China NE Normal Univ Coll Life Sci Changchun 130024 Peoples R China

Biodegradable polymer blends based on biosourced polymers, namely polylactide (PLA) and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)), were prepared by melt compounding. The effects of P(3HB-co-4HB) on the miscibility, phase morphology, thermal behavior, mechanical properties, and biodegradability of PLA/P(3HB-co-4HB) blends were investigated. The blend was an immiscible system with the P(3HB-co-4HB) domains evenly dispersed in the PLA matrix. However, the Tg of P(3HB-co-4HB) component in the blends decreased compared with neat P(3HB-co-4HB), which might be attributed to that the presence of the phase interface between PLA and P(3HB-co-4HB) resulted in enhanced chain mobility near interface. The addition of P(3HB-co-4HB) enhanced the cold crystallization of PLA in the blends due to the nucleation enhancement of PLA caused by the enhanced chain mobility near the phase interface between PLA and P(3HB-co-4HB) in the immiscible blends. With the increase in P(3HB-co-4HB) content, the blends showed decreased tensile strength and modulus;however, the elongation at beak was increased significantly, indicating that the inherent brittlement of PLA was improved by adding P(3HB-co-4HB). The interesting aspect was that the biodegradability of PLA is significantly enhanced after blends preparation. POLYM. COMPOS., 2012. (C) 2012 Society of Plastics Engineers

关键词： programmable logic arrays Cold crystallization Polymer blends Beak Blends Polylactides biodegradability Phase interfaces

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THE USE OF CNN MODELS IN THE SUBCORTICAL VISUAL PATHWAY

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-FUNDAMENTAL THEORY AND APPLICATIONS 1993年第3期40卷 182-195页

作者： ROSKA, T HAMORI, J LABOS, E LOTZ, K ORZO, L TAKACS, J VENETIANER, PL VIDNYANSZKY, Z ZARANDY, A SEMMELWEIS SCH MED DEPT ANAT ISTH-1450 BUDAPESTHUNGARY

The CNN model is now a paradigm of cellular analog programmable multidimensional processor array with distributed local logic and memory. It has turned out that for biological sensory information processing this model is so natural that a lot of neuroanatomical structures can be directly translated into CNN models. In this paper first we show the equivalent notions of neuroanatomy and the CNN model, motivated by studying the visual system. Next, various, mainly subcortical phenomena are studied. Simple effects like directional sensitivity and length tuning are modeled. A more accurate retina model has been developed taking into account some effects of amacrine cells. It is shown that the standard errors occurring in simple models of retinal illusions can be eliminated by using our more accurate models including delays. LGN effects with and without cortical feedback are modeled as well. Their CNN models are simple. Furthermore, simple texture detection effects and motion illusions are explained by neuromorphic CNN models. Local connectivity within a finite neighborhood, equivalent templates of different receptive field organizations, delay-templates have proved to be key issues. The goal is to translate known effects into CNN models and to show a framework for further studies.

关键词： Cellular neural networks Biological system modeling programmable logic arrays Retina Delay Visual system Neuromorphics Multidimensional systems Turing machines Biosensors

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Preparation of biocompatible, biodegradable and sustainable polylactides catalyzed by aluminum complexes bearing unsymmetrical dinaphthalene-imine derivatives via ring-opening polymerization of lactides

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CATALYSIS SCIENCE & TECHNOLOGY 2015年第9期5卷 4644-4652页

作者： Gao, Bo Li, Dongni Li, Xiang Duan, Ranlong Pang, Xuan Cui, Yuan Duan, Qian Chen, Xuesi Chinese Acad Sci Changchun Inst Appl Chem Key Lab Polymer Ecomat Changchun 130022 Peoples R China Changchun Univ Sci & Technol Sch Mat Sci & Engn Changchun 130022 Peoples R China

A number of half-salen aluminum complexes bearing unsymmetrical [ONN]-type ligands were prepared from tridentate dinaphthalene-imine derivatives. These complexes were characterized by H-1 and C-13 NMR spectroscopy, elemental analysis and single crystal X-ray diffraction analysis. These complexes were employed for rac-lactide and L-lactide polymerization. Upon activation with isopropanol, complex (S)-B-6 (R-1 = R-2 = R-4 = H;R-3 = F) showed the highest activity (a monomer conversion of 94.6%) amid these aluminum complexes for the ring-opening polymerization of L-lactide;and complex (S)-B-2 (R-1 = R-2 = R-3 = H;R-4 = Bu-t) showed the highest stereoselectivity for the ring-opening polymerization of rac-lactide, obtaining a polylactide (PLA) with a Pm of 0.69. The polymerization kinetics utilizing (S)-B-6 as a catalyst were researched in detail. The data on the polymerization kinetics revealed that the rate of polymerization was first-order with respect to the monomer and the catalyst. There was a linear relationship between the L-lactide conversion and the number-average molecular weight of PLA.

关键词： programmable logic arrays Bearings Ring opening polymerization ALUMINIUM COMPLEXES Polylactides monomers Polymerization aluminium Polymerization kinetics non-symmetric

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Burned data time series for Tropical Africa (1981-2000) with the daily tile NOAA/NASA Pathfinder AVHRR 8-km Land dataset

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INTERNATIONAL JOURNAL OF REMOTE SENSING 2006年第5-6期27卷 1119-1134页

作者： Moreno-Ruiz, JA Barón-Martinez, J Sagrado-Martínez, J Univ Almeria Dept Lenguajes & Computac Almeria 04120 Spain

The NOAA/NASA Pathfinder AVHRR 8-km Land (PAL) dataset provides an invaluable source of data for researching global changes on the Earth's surface due to its long time and spatial scales. However, because of errors, the original Global Daily PAL data (1981-1994) have been reprocessed into a tiled time series file configuration. Reprocessing involved calculating the correct solar zenith angles and relative azimuth angles, and re-extracting radiances from the original Channel I and 2 reflectance values. The high dependence of the burned area algorithm (BAA) with respect to reflectance channel uncertainty led us, as a first goal, to compare the two dataset releases to determine the magnitude of their differences and how burned area estimations could be affected by them: the new burned data estimations from the Tile PAL release are around 30% higher than those from the original one. The second goal was to present and briefly analyse the monthly burned time series (13S) for Tropical Africa for the period 19812000: stational indexes show that the burned pixel peaks in the time series for northern Tropical Africa appear in winter (from December to February), while ill southern Tropical Africa they are in summer (from July to September). Chronograms show a significant interannual seasonal variation in both (being more apparent in the southern region) possibly as a consequence of the influence of the El Nino Southern Oscillation (ENSO) phenomenon-induced Sea Surface Temperature (SST) anomalies in the Pacific Ocean (annual average SST-3.4 and delayed one year and a half BS anomalies were found in the period considered).

关键词： Data sources LRIT1 gene SHCBP1 gene Burns Pacific Ocean Azimuthal angle programmable logic arrays El Nino Southern Oscillation time series data Tile Time series Earth surface Africa tropical Dataset

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Physical extruder foaming of poly(lactic acid)processing and foam properties

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POLYMER ENGINEERING AND SCIENCE 2013年第5期53卷 941-949页

作者： Larsen, Age Neldin, Christoffer SINTEF Mat & Chem NO-0314 Oslo Norway Borealis AB SE-44486 Stenungsund Sweden

The article describes extrusion foaming of poly(lactic acid) (PLA) using carbon dioxide in the supercritical state as foaming agent emphasizing the steps required to establish a stable extrusion process. Low melt strength of PLA plays a role in optimizing processing conditions. The tests included PLA grades of different viscosity in addition to a chain extender. Processing at low temperature is possible due to the plasticizing effect of the CO2 on the PLA melt and a sufficiently low melt temperature is also a prerequisite in production of stable foams due to improved melt strength. Foams were characterized by density, cell structure, crystallinity, and mechanical properties in compression. Low density, microcellular foams with density down to 2030 kg/m3 were obtained for three different PLA grades. Varying die temperature and pressure drop rate we can explain observed abrupt drops in density with increasing CO2 content by the interplay between cell nucleation and gas diffusivity at given temperatures. An effect on melt strength similar to using a chain extender is achieved by lowering the melt temperature at the die. Observed variations in sample crystallinity do not correlate with foam density. The PLA foams have good energy absorption capability. POLYM. ENG. SCI., 2013. (c) 2012 Society of Plastics Engineers

关键词： poly(lactic acid) energy absorption ability Mechanical properties MELT STRENGTH extrusion process melting point programmable logic arrays Carbon Dioxide Foaming

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THE EFFICIENT IMPLEMENTATION AND ANALYSIS OF A HYBRID NUMBER SYSTEM PROCESSOR

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-ANALOG AND DIGITAL SIGNAL PROCESSING 1993年第6期40卷 382-392页

作者： LAI, FS IBM Thomas J. Watson Research Center Yorktown Heights NY USA

A hybrid number system processor designed with the anti-logarithm PLA is described. In the hybrid number system, a linear interpolation is used in order to make accurate conversions between FLP and LNS numbers. Originally, a multiplier was used to do the interpolation. In this paper, the anti-logarithm PLA is shown to have smaller silicon area, comparable overall performance, and structured design. The basic arithmetic operations and processor architecture are explained for performing addition, subtraction, multiplication, division, and square root. The conversion errors are analyzed mathematically. The Taylor series approximation is used as the framework for analysis of the conversion errors of logarithm, anti-logarithm, multiplication/division, and addition/subtraction. The analyses indicate that the Taylor series truncation results in very small error when the ROM size is properly chosen for the desired precision. Consequently, the finite width truncation becomes the major source of conversion errors.

关键词： programmable logic arrays Interpolation Read only memory Silicon Arithmetic Error analysis Taylor series Digital signal processing logic design Process design

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A STATISTICAL-ANALYSIS OF PLA FOLDING

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IEEE TRANSACTIONS ON COMPUTER-AIDED DESIGN OF INTEGRATED CIRCUITS AND SYSTEMS 1986年第1期5卷 39-51页

作者： MAKARENKO, DD TARTAR, J Department of Computing Science University of Alberta Edmonton AB Canada

Current understanding of the PLA folding problem is limited to simple empirical evidence from studies of heuristic methods. This paper presents a theoretical approach through an analytical and statistical analysis. The problem is first mapped into a set theoretic model. Using a random selection heuristic as a basis, a probability density function (PDF) is derived for the expected number of folds under a set of simplifying assumptions. This PDF is derived in terms of the three fundamental properties of a PLA, r the number of rows, c the number of columns, and d the density. Empirical results obtained from folding thousands of randomly generated PLA's verify the accuracy of the derived probability density function. A technique is developed whereby the PDF can also be used to predict the size of optimal folding sets. A new folding heuristic is introduced which is shown to perform better than other heuristic algorithms in the literature, when applied to a set of randomly generated PLA's. This is the first folding heuristic to have an analytical basis for its expected results, as derived from the PDF function.

关键词： Statistical analysis programmable logic arrays Probability density function logic design Heuristic algorithms Very large scale integration logic circuits Process design Automatic control

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Thermal Pretreatment of Kudzu Biomass (Pueraria lobata) as Filler in Cost-Effective PLA Biocomposite Fabrication Process

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POLYMER ENGINEERING AND SCIENCE 2015年第2期55卷 340-348页

作者： Salak, Feridoun Uemura, Satoshi Sugimoto, Kiyotoshi Nara Prefectural Govt Nara Prefecture Inst Ind Dev Life Mat Grp Nara 6308031 Japan

This article aims on the fabrication of cost-effective polylactic acid (PLA) biocomposites using kudzu biomass derivatives as new filler. In this way, it has been realized that pretreatment of the filler was an essential requirement. We demonstrated thermal pyrolysis process that targeted to extraction and isolation of all extractable and unnecessary compounds such as intracellular water and bio-oil from the biomass. Also, to further improve the compatibility of the filler with PLA, noncatalytic thermal esterification reactions of kudzu after thermal pyrolysis (called char) were carried out as second pretreatment stage in the presence of phthalic anhydride. Kudzu derivatives obtained from either first or second pretreatment reactions were melt-blended with PLA in various rates. The blends were then compression molded into dumbbell specimens. Physicomechanical properties of the prepared biocomposites were evaluated using several analytical techniques. It was found that biocomposites containing treated biomass had higher values of physicomechanical properties than untreated ones. The final rate of filler to PLA with acceptable properties was set up to 50%. Obviously, the cost of PLA can be reduced using higher rates of low-cost filler on a finished-product basis. Extracted valuable compounds from biomass via thermal pyrolysis could be another benefit of the process. POLYM. ENG. SCI., 55:340-348, 2015. (c) 2014 Society of Plastics Engineers

关键词： programmable logic arrays Fillers Biomass Kudzu BIOCOMPOSITE pyrolysis

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CONCURRENT ERROR-DETECTION IN HIGHLY STRUCTURED logic-arrays

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IEEE JOURNAL OF SOLID-STATE CIRCUITS 1987年第4期22卷 583-594页

作者： FUCHS, WK CHEN, CYR ABRAHAM, JA Computer Systems Group Coordinated Science Laboratory University of Illinois Urbana IL USA

Two strategies for encoding the inputs and outputs of highly structured logic arrays (HSLAs) are introduced. The two schemes are particularly relevant for concurrent error detection of both permanent and nonpermanent errors in programmable logic arrays (PLAs) and read-only memories (ROMs). The first method of concurrent error detection (CED) is based on a comprehensive fault model and relies on detection of unidirection errors. The second approach relies on a detailed examined of decoder layouts resulting in fault avoidance through layout rules, which avoid failures causing unidirectional errors. Efficient parity techniques are shown to provide a low-overhead solution to concurrent error detection when coupled with appropriate fault-avoidance techniques.

关键词： logic arrays Fault detection Circuit faults programmable logic arrays logic devices Encoding Very large scale integration Testing Decoding Read only memory

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Physical Layer Authentication for Industrial Control Based on Convolutional Denoising Autoencoder

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IEEE INTERNET OF THINGS JOURNAL 2024年第9期11卷 15633-15641页

作者： Chen, Yanru He, Haoyu Liu, Shengjie Zhang, Yuanyuan Li, Yang Xing, Bin Guo, Bing Chen, Liangyin Sichuan Univ Coll Comp Sci Chengdu 610065 Peoples R China Sichuan Univ Inst Ind Internet Res Chengdu 610065 Peoples R China Inst Southwestern Commun Sci & Technol Secur Commun Lab Chengdu 610041 Peoples R China Ind Big Data Applicat Technol Natl Engn Lab Beijing 100040 Peoples R China

Industrial control systems rely on wireless devices and sensors, necessitating critical security. Physical layer authentication (PLA) is a promising mechanism for device authentication, utilizing its unique spatiotemporal characteristics and channel state randomness, which offers unforgeability and high informatics security with low computational overhead and efficiency in resource-constrained scenarios. However, existing PLA mechanisms face challenges in complex industrial wireless environments, including insufficient accuracy, computational complexity, inadequate noise consideration, and poor performance. To address these challenges, we propose a convolutional denoising autoencoder (CDAE) model that reduces feature dimensions, eliminates noise, and extracts key vectors. The weighted k -nearest neighbor algorithm classifies the extracted vectors for comprehensive authentication in control system networks. Accurate authentication enables efficient detection of malicious attacks. Simulation experiments show that using CDAE-extracted feature vectors achieves over 95% accuracy with only 1% training samples, surpassing channel state information-based authentication by 46.15%, validating the proposed mechanism's effectiveness.

关键词： programmable logic arrays Authentication Feature extraction Wireless communication Security Physical layer Industrial control Denoising autoencoder (DAE) industrial control system industrial wireless network physical layer authentication (PLA)

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