一种引入互斥关系的功能单元分配算法

为使条件分支数据通道中功能单元的分配结果得到进一步优化,在数据流图操作相容性分析中引入操作间互斥关系,并构建基于图论的分配模型.使用团划分算法在该模型上进行功能单元分配,同时提出一种针对功能单元分配问题的团划分启发式方法.不仅提高了团划分算法求解功能单元分配问题的计算结果一致性,而且使算法的收敛速度得以提高.根据实验结果,该算法得到的数据通道中所需功能单元平均减少了41%,同时执行速度加快了50%.     

Tunability of physical properties of (Cd:Zn)S thin film by Close Space Sublimation Process (CSSP)

The present paper reports on a systematic study of the influence of Zn alloying on the structural and optical properties of Cd1 xZnxS thin films. X-ray diffraction study for structural analysis reveals that the two binary compounds have been completely transformed into ternary compound with hexagonal (wurtzite) structure with preferred orientation along c-direction with (002) planes. The optical properties such as optical constants and band gap energy of the films were examined by using spectroscopic ellipsometer and Photospectrometery. It was found that the optical constants (n and k) decrease with the addition of Zn content in the alloy. It was also confirmed that the band gap increases with increasing Zn amount in the alloy and is attributed to quantum size effect in the grain size. Raman spectroscopy analysis shows one dominant phonon band at 326 cm 1, the so-called longitudinal optical (LO) mode for all the alloy composition (x). The appearance of a single phonon band in the Raman spectra established the formation of single phase hexagonal structured Cd1 xZnxS thin film. The LO band is asymmetrically broaden and high frequency shifted due to potential fluctuation caused by the dopant material. The AFM results showed that the surface roughness was decreased with increasing Zn content.     

Predicting multistage financial distress: Reflections on sampling,feature and model selection criteria

This research proposes a prediction model of multistage financial distress (MSFD) after considering contextual and methodological issues regarding sampling, feature and model selection criteria. Financial distress is defined as a three‐stage process showing different nature and intensity of financial problems. It is argued that applied definition of distress is independent of legal framework and its predictability would provide more practical solutions. The final sample is selected after industry adjustments and oversampling the data. A wrapper subset data mining approach is applied to extract the most relevant features from financial statement and stock market indicators. An ensemble approach using a combination of DTNB (decision table and naïve base hybrid model), LMT (logistic model tree) and A2DE (alternative N dependence estimator) Bayesian models is used to develop the final prediction model. The performance of all the models is evaluated using a 10‐fold cross‐validation method. Results showed that the proposed model predicted MSFD with 84.06% accuracy. This accuracy increased to 89.57% when a 33.33% cut‐off value was considered. Hence the proposed model is accurate and reliable to identify the true nature and intensity of financial problems regardless of the contextual legal framework.     

Enhanced ductility of Mg–3Al–1Zn alloy reinforced with short length multiwalled carbon nanotubes using a powder metallurgy method

Mg–3Al–1Zn–CNTs composites, with different weight fractions(0.25–1.0 wt%) of carbon nanotubes(CNTs) were successfully fabricated via a powder metallurgy method. The processing parameters were adopted in such a way to have uniform dispersion of short length CNTs without any damage, as well as re fi ned and dissolved β phases structures throughout the composite matrix. The composite exhibited impressive increase in microhardness(about+23%) and tensile failure strain value(about+98%) without signi fi cant compromise in tensile strength, compared to the un-reinforced Mg–3Al–1Zn alloy. The synthesized composites can be used in automotive and aerospace industries due to their low density and high speci fic strength.     

Strength of Concrete Filled Steel Tubular Columns

Introduction The steel tube in a concrete filled tubular column (CFT) acts as both longitudinal and lateral reinforcement, and is thus subjected to biaxial stresses of longitudinal compression and hoop tension. At the same time, con- crete is stressed tri…     

Epidemiological modeling of passive worm propagationon the P2P file-sharing network

The peer-to-peer(P2P) file-sharing network as a vehicle of disseminating files has become very popular.The appearance of dozens of kinds of passive worms on this network has,however,made it unsecured.This problem has been paid attention and a few of models for passive worm propagation has been presented.Unfortunately,the dynamic properties of this network are ignored in these models.Given the fact,the characteristics of both this network and the passive worm are identified,and on this basis a new mathematical model of passive worm propagation on the P2P network is presented in applying epidemiology in this paper.Note that the dynamic properties of this network are considered in the presented model.The model has been validated by large scale simulation experiments,which demonstrates that the presented model may be used for analyzing the behaviors of passive worms and predicting the trend of their propagation.     

Suitable energy platform significantly improves charge separation of g-C_3N_4 for CO_2 reduction and pollutant oxidation under visible-light

The photocatalytic activities of g-C_3N_4 can be significantly improved by increasing life time of the photogenerated charges. Here, in this work we introduced TiO_2 as proper energy platform to accept the photogenerated electrons from g-C_3N_4 during photocatalysis. The nanophotocatalysts formed from the combination of a suitable amount of TiO_2 nanoparticles and g-C_3N_4 nanosheets showed 8.75 and 4.22% enhancement in photocatalytic activities for CO_2 reduction and 2-chlorophenol(2-CP) degradation under visible light illumination as compared to bare g-C_3N_4. Based on the surface photovoltage spectra, photoluminescence spectra and examination of formed hydroxyl radicals, it was confirmed that these enhanced photoactivities were attributed to the much-improved charge separation via the electron transfer from g-C_3N_4 to TiO_2. From trapping experiments,it was found that hydroxyl radicals were the major species involved in the photocatalytic degradation of 2-CP.This study is helpful to synthesize efficient photocatalysts to cope with energy and environmental issues.     

新型多孔聚苯胺在超级电容器电极材料中的应用

通过一个简便的方法,将苯胺单体在含氯化钾(KCl)的盐酸溶液中聚合制备出多孔聚苯胺(polyaniline,PANI).以KC1作为形成多孔聚苯胺的赝模板,既有效地避免了有机溶剂和硬/软模板的使用,又减轻了对环境的污染.由于具有独特的多孔结构和相互交错的纳米棒结构,多孔聚苯胺的比表面积较大,显示出良好的电化学性能.电化...     

Investigation of functional, physical, mechanical and thermal properties of TiO2 embedded polyester hybrid composites: A design of experiment (DoE) study

This paper presents a study on the Design of Experiments(Do E) approach to optimize the fabrication parameters of titania(TiO_2) embedded glass fiber reinforced polyester hybrid composites(HCs). HCs of unsaturated polyester resin(UPR) were fabricated using methyl ethyl ketone peroxide(MEKP) as the curing agent by hand lay-up process(HLUP) and compression molding technique(CMT). The fabrication parameters were optimized by Taguchi Do E(an orthogonal array of L25) using 3 control factors(concentration of TiO_2, concentration of MEKP and curing temperature) having 5 levels each. Statistical tools were employed to identify significant factors affecting tensile strengths and its reproducibility during HLUP. It was found that the concentration of TiO_2 in HCs significantly influenced the tensile strength(TS) followed by MEKP concentration and curing temperature. The highest value of TS was obtained at 3 wt% TiO_2, 2 wt% MEKP and 80 °C. Nevertheless, the sensitivity of TiO_2 concentration was basis for fabrication of polyester titania glass fiber hybrids(PTGFHs), which were further investigated for density and void fractions, linear shrinkage, flexural strength, impact strength, hardness and thermal behaviors. Moreover, cross-linking and hydrogen-bonding between polymeric chains, styrene, silica content of glass fiber and TiO_2 particles in PTGFHs were confirmed by Fourier transform infrared spectroscopy.