摘要 :
A novel triphenol, 4-(3,3-dihydro-7-hydroxy-2,4,4-trimethyl-2H-l-benzopyran-2-yl)-l,3- benzenediol, was described with high product yield of 99.2% and high purity of 94.35% analyzed by HPLC. The melting point temperature (Tm) of t...
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A novel triphenol, 4-(3,3-dihydro-7-hydroxy-2,4,4-trimethyl-2H-l-benzopyran-2-yl)-l,3- benzenediol, was described with high product yield of 99.2% and high purity of 94.35% analyzed by HPLC. The melting point temperature (Tm) of this tri-phenol was 223.4℃ with melting range from 197.4℃ to 228.9℃ and decomposition temperature was 239.4℃ by scanning calorimeter (DSC) and thermal gravimetric analysis (TGA). Trifunctional epoxy resin (TF-EPOXY) was further synthesized by the epoxidation reaction of tri-phenol and epichlorohydrin. The theoretical epoxy equivalent weight of synthesized TF-EPOXY is 156. The structure of tri-phenol and trifunctional epoxy were characterized by infra-red and ESI-MS. The hardener Diaminodiphenyl-sulfone (DDS) and diaminodiphenyl-methane (DDM) were used to cure TF-EPOXY, respectively. The curing activation energies were investigated by DSC to be 66.2kJ/mol and 55.4kJ/mol respectively. The glass transition temperature of cured TF-EPOXY and cured diglycidyl ether of bisphenol A type epoxy CYD 128 were compared by the experimental data of dynamic mechanical thermal analysis (DMTA). The results showed that Tg of TF-EPOXY/DDS system was 290.1 ℃, 73.9℃ higher than CYD-128/DDS system; Tg of TF-EPOXY/DDM system was 240.2℃, 60.1℃ higher than CYD-128/DDM system. TF-EPOXY resin was compatible with CYD128, and the mixture of TF-EPOXY and CYD 128 was cured by DDS and DDM. The Tgs of cured products gradually increased with increasing the ratio of TF-EPOXY and leveled off a certain value.
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摘要 :
A novel triphenol, 4-(3,3-dihydro-7-hydroxy-2,4,4-trimethyl-2H-l-benzopyran-2-yl)-l,3- benzenediol, was described with high product yield of 99.2% and high purity of 94.35% analyzed by HPLC. The melting point temperature (Tm) of t...
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A novel triphenol, 4-(3,3-dihydro-7-hydroxy-2,4,4-trimethyl-2H-l-benzopyran-2-yl)-l,3- benzenediol, was described with high product yield of 99.2% and high purity of 94.35% analyzed by HPLC. The melting point temperature (Tm) of this tri-phenol was 223.4℃ with melting range from 197.4℃ to 228.9℃ and decomposition temperature was 239.4℃ by scanning calorimeter (DSC) and thermal gravimetric analysis (TGA). Trifunctional epoxy resin (TF-EPOXY) was further synthesized by the epoxidation reaction of tri-phenol and epichlorohydrin. The theoretical epoxy equivalent weight of synthesized TF-EPOXY is 156. The structure of tri-phenol and trifunctional epoxy were characterized by infra-red and ESI-MS. The hardener Diaminodiphenyl-sulfone (DDS) and diaminodiphenyl-methane (DDM) were used to cure TF-EPOXY, respectively. The curing activation energies were investigated by DSC to be 66.2kJ/mol and 55.4kJ/mol respectively. The glass transition temperature of cured TF-EPOXY and cured diglycidyl ether of bisphenol A type epoxy CYD 128 were compared by the experimental data of dynamic mechanical thermal analysis (DMTA). The results showed that Tg of TF-EPOXY/DDS system was 290.1 ℃, 73.9℃ higher than CYD-128/DDS system; Tg of TF-EPOXY/DDM system was 240.2℃, 60.1℃ higher than CYD-128/DDM system. TF-EPOXY resin was compatible with CYD128, and the mixture of TF-EPOXY and CYD 128 was cured by DDS and DDM. The Tgs of cured products gradually increased with increasing the ratio of TF-EPOXY and leveled off a certain value.
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To understand the mechanics of materials, it is important to faithfully model the physics due to interactions at the microstructural scales. While brute-force modeling of all the details of the microstructure is too costly, curren...
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To understand the mechanics of materials, it is important to faithfully model the physics due to interactions at the microstructural scales. While brute-force modeling of all the details of the microstructure is too costly, current homogenized continuum models suffer from their inability to sufficiently capture the correct physics - especially where localization and failure are concerned. To overcome this limitation, a multi-scale continuum theory is proposed so that kinematic variables representing the deformation at various scales are incorporated. The method of virtual power is then used to derive a system of coupled governing equations, each equation representing a particular scale and its interactions with the macro-scale. A constitutive relation is then introduced to preserve the underlying physics associated with each scale. The inelastic behavior is represented by multiple yield functions, each representing a particular scale of microstructure, but collectively coupled through the same set of internal variables. We present some applications of the theory in high strength steels, whose microstructure consists of two populations of inclusions at distinct scales, in an alloy matrix. We then give an overview of undergoing research including the modeling of cortical bone, and thermal-mechanical-chemical-electrical materials
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1. Fly ash in flue gas increased on account of gangue added in fuel, which in favor of the transformation of Hg~o to Hg~p; 2. FF has better ability to capture fly ash especially the submicron particles, resulted in most of mercury...
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1. Fly ash in flue gas increased on account of gangue added in fuel, which in favor of the transformation of Hg~o to Hg~p; 2. FF has better ability to capture fly ash especially the submicron particles, resulted in most of mercury (96.71%) input was captured by FF;
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The sufficient condition that guarantees perfect segmentation for an image with PCNNs when the intensity ranges of adjacent regions overlap is one of the main results presented in reference[1]. However, with deep understanding of ...
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The sufficient condition that guarantees perfect segmentation for an image with PCNNs when the intensity ranges of adjacent regions overlap is one of the main results presented in reference[1]. However, with deep understanding of the derivation process used in [1], it is shown in this paper that it is not a sufficient condition. The conditions for perfect image segmentation when there is an overlap in intensity ranges of adjacent regions are still remained unsolved.
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摘要 :
The sufficient condition that guarantees perfect segmentation for an image with PCNNs when the intensity ranges of adjacent regions overlap is one of the main results presented in reference[1]. However, with deep understanding of ...
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The sufficient condition that guarantees perfect segmentation for an image with PCNNs when the intensity ranges of adjacent regions overlap is one of the main results presented in reference[1]. However, with deep understanding of the derivation process used in [1]. it is shown in this paper that it is not a sufficient condition. The conditions for perfect image segmentation when there is an overlap in intensity ranges of adjacent regions are still remained unsolved.
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In this paper,through the research of reclamation practice and effect of tailings bank for many years in arid area,the results showed that the main limiting factors which affect the tailings reclamation of the arid area is includi...
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In this paper,through the research of reclamation practice and effect of tailings bank for many years in arid area,the results showed that the main limiting factors which affect the tailings reclamation of the arid area is including drought,poor soil,heavy metal toxicity,etc..Proposed the reclamation mode of tailings bank which is composed of leveling,desert gravel soil covering,organic fertilizer and water retention agent fertilizing,reasonable proportion of grass and shrub distributing,and native plant species sowing.Reclamation plant species should select those which have the properties of drought tolerance,poor resistance and heavy metal resistance,such as tamarisk,calligonum,salsola.The practice showed that the reclamation of tailings bank in arid area not only can realize reclamation and improvement,but also can prevent windstorms,fasten sand,restore local landscape.At the same time,it has the character of less investment,significant effect,etc..The results of this research can be used as technical reference for the same type of land reclamation of drought mine.
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摘要 :
In this paper,through the research of reclamation practice and effect of tailings bank for many years in arid area,the results showed that the main limiting factors which affect the tailings reclamation of the arid area is includi...
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In this paper,through the research of reclamation practice and effect of tailings bank for many years in arid area,the results showed that the main limiting factors which affect the tailings reclamation of the arid area is including drought,poor soil,heavy metal toxicity,etc..Proposed the reclamation mode of tailings bank which is composed of leveling,desert gravel soil covering,organic fertilizer and water retention agent fertilizing,reasonable proportion of grass and shrub distributing,and native plant species sowing.Reclamation plant species should select those which have the properties of drought tolerance,poor resistance and heavy metal resistance,such as tamarisk,calligonum,salsola.The practice showed that the reclamation of tailings bank in arid area not only can realize reclamation and improvement,but also can prevent windstorms,fasten sand,restore local landscape.At the same time,it has the character of less investment,significant effect,etc..The results of this research can be used as technical reference for the same type of land reclamation of drought mine.
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Based on the garment brands randomly selected in Shanghai, Zhejiang, Guangdong, Fujian, Henan, Jiangsu, and Hubei, this paper learns about the basic information of the garment brand channel manager through the manager himself, sto...
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Based on the garment brands randomly selected in Shanghai, Zhejiang, Guangdong, Fujian, Henan, Jiangsu, and Hubei, this paper learns about the basic information of the garment brand channel manager through the manager himself, store manager, and the company's other staff. Making use of telephone, Email, interviews, networking online contact and other data collection methods, understanding the survey questionnaires about the channel manager's gender, age, education, occupation, marital status, working years, salary, and treatment, sorting out the role information of the channel manager in the current domestic leisure garment market, and representing the data in charts, this paper is aimed to provide some referential information for clothing brand enterprises while they choose their channel manager.
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A novel Polymethoxylsiloxane (PMOS) with dense pendant methoxy groups was synthesized from cyclosiloxane monomers by ring-opening polymerization and dehydrocoupling reaction. Synthesis reactions were followed by IR spectroscopy an...
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A novel Polymethoxylsiloxane (PMOS) with dense pendant methoxy groups was synthesized from cyclosiloxane monomers by ring-opening polymerization and dehydrocoupling reaction. Synthesis reactions were followed by IR spectroscopy and 29Si NMR tests. PMOS was incorporated with polydimethylsiloxane (PDMS) via hydrolyzation and condensation to prepare crosslinked polysiloxane, and the apparent activation energy for curing reaction was 3.92 KJ/mol.High-croslinked PMOS phases were in-situ formed and the average crosslink density increased with increasing of the loading of PMOS. It was detected that these PMOS phases improved thermal and mechanical properties of polysiloxane significantly.TG analysis results showed that the temperature at 10 % mass loss for the neat crosslinked PMOS was as high as 760 ℃.Thermal decomposition process of polysiloxane cured with PMOS divided into two stages, and the residual mass at 500 ℃ was 66 wt %. The pyrolysis reaction order was 0.974 and the activation energy for degradation was 78.0 kJ/mol. The crosslink density, tensile stress and elastic module went up as the loading of PMOS increased. Tensile stress and elastic module increase twice and three times, respectively, when the PMOS loading increases from 15.1 wt% to 41.6 wt%. This novel PMOS material is promising for applications in heat resisting resins, adhesives and sealants.
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