The measures of steam curing and early-strengthening agents to promote the precast components to reach the target strength quickly can bring different degrees of damage to the concrete.Based on this,the new nanomateri...The measures of steam curing and early-strengthening agents to promote the precast components to reach the target strength quickly can bring different degrees of damage to the concrete.Based on this,the new nanomaterial CSH-the hydration product of cement effectively solves these measures’disadvantages,such as excessive energy consumption,thermal stress damage,and the introduction of external ions.In this paper,the effect of CSH on the early strength of precast fly ash concrete components was investigated in terms of setting time,workability,and mechanical properties and analyzed at the microscopic level using hydration temperature,XRD,and SEM.The results showed that under the same workability,CSH could significantly reduce the amount of admixture,shorten the final setting time,almost not affect the initial setting time,and accelerate the hydration of cement.At the optimum dose of 5%,the mechanical properties of the specimens were improved by more than 98%within 12 h of hydration,resulting in an earlier release time of 12 h and no risk of strength inversion later.The results of this paper give theoretical support to the behavior of precast components under steam-free curing.展开更多
This study aimed to learn the recurrence rate in the retreatment TB patients with sputum smear and/or culture positive (ss+ and/or c+) two years after they were declared cured, and to explore causes of recurrence ...This study aimed to learn the recurrence rate in the retreatment TB patients with sputum smear and/or culture positive (ss+ and/or c+) two years after they were declared cured, and to explore causes of recurrence in order to improve long-time treatment outcome. 5 cities were selected as research locations. Recurrence of TB was judged by chest X-ray examination together with sputum smear and culture examination.展开更多
The aim of this work was to explore the physicochemical and structural properties,lipid oxidation and antioxidant capacity of the peptides extracted from Cantonese cured meat and as well as to investigate the effect o...The aim of this work was to explore the physicochemical and structural properties,lipid oxidation and antioxidant capacity of the peptides extracted from Cantonese cured meat and as well as to investigate the effect of drying time on the sarcoplasmic and myofibrillar proteins of Cantonese cured meat.The results suggested that salting out,protein oxidation and heat treatment were closely related to surface hydrophobicity and the secondary structure of peptides was changed by processing.And the peroxide value and the value of tributyltin compounds were different in evaluating the degree of lipid oxidation.Glu and His were the major amino acid.The approximate molecular weights of the sarcoplasmic proteins and myofibrillar proteins ranged from 31 kDa to 50 kDa and 66 kDa,respectively.The results indicated that reducing the levels of protein oxidation and improvement of the antioxidant properties should be of great interest to preserve the nutritional quality of meat products and prolong preservation period.展开更多
The main agronomic traits,economic traits,appearance quality,main chemical components,gas composition and physical parameters of 10 flue cured tobacco varieties were investigated in the experiment.And the field natura...The main agronomic traits,economic traits,appearance quality,main chemical components,gas composition and physical parameters of 10 flue cured tobacco varieties were investigated in the experiment.And the field natural incidence of the main diseases was investigated.The results showed that main agronomic characters of the 10 varieties were in line with the breeding objectives,among which 5 varieties have good economic characters;5 varieties have good appearance quality;6 varieties have coordinated chemical composition and high potassium content;9 varieties have good smoke components and physical indicators.展开更多
Foreword ISO(the International Organization for Standardization)is a worldwide federation of national standards bodies(ISO member bodies).The work of preparing International Standards is normally carried out through I...Foreword ISO(the International Organization for Standardization)is a worldwide federation of national standards bodies(ISO member bodies).The work of preparing International Standards is normally carried out through ISO technical committees.Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee.展开更多
Objective To analyse infection rate of ventricular hemorrhage after lateral ventricle drainage and evaluate the method and measure of precaution. Methods Patients were divided into first and second groups according to...Objective To analyse infection rate of ventricular hemorrhage after lateral ventricle drainage and evaluate the method and measure of precaution. Methods Patients were divided into first and second groups according to the remaining time of drainage tube and into A and B groups according to drainage in one or two sides. After operation the infection condition of insert tube was observed and blood was cultivated regularly. Results The infection rate in the first group was significantly shorter than that in the second one (P 【 0. 01), while it was no significantly difference between groups A and B (P 】 0. 05). Conclusion To remain drainage tube for one to two weeks is safer than for more than two weeks. The infection rate is higher in group with drainage in two sides than in one. In addition, it is obviously related to the patient’s body condition and immunity. 6 refs,2 tabs.展开更多
A new method concerning with the simultaneous reinforcing and toughening of polypropylene (PP) was reported. Dynamical cure of the epoxy resin was successfully applied in the PP/maleic anhydride-grafted styrene-ethy...A new method concerning with the simultaneous reinforcing and toughening of polypropylene (PP) was reported. Dynamical cure of the epoxy resin was successfully applied in the PP/maleic anhydride-grafted styrene-ethylene-butylene-styrene (SEBS) triblock copolymer, and the obtained blends named as dynamically cured PP/MAH-g-SEBS/epoxy blends. The stiffness and toughness of the blends are in a good balance, and MAH-g-SEBS was acted as not only an impact modifier but also a compatibilizer. The structure of the dynamically cured PP/MAH-g-SEBS/epoxy blends is the embedding of the epoxy particles by the MAH-g- SEBS.C2009 Xue Liang Jiang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
The mechanism of carotenoid degradation and the changes in the activities of related enzymes in flue-cured tobacco at the leaf-drying stage during the bulk-curing process were studied in order to provide theoretical b...The mechanism of carotenoid degradation and the changes in the activities of related enzymes in flue-cured tobacco at the leaf-drying stage during the bulk-curing process were studied in order to provide theoretical basis for optimization of curing technology. The effect of different rising speeds of temperature on the carotenoid degradation and the related enzymes activities at the color-fixing stage during the bulk curing process was studied by using the electric-heated fluecuring barn designed by Henan Agricultural University, China, based on curing technology with yellowing at low temperature and moderate humidity and leaf drying at moderate humidity. The results showed that the carotenoid degradation components (β-carotene, lutein, neoxanthin, and violaxthin) decreased gradually at the color-fixing stage during the bulk curing process. The carotenoid degradation components viz.,β-carotene, lutein, neoxanthin, and violaxthin at the slow heating curing (T1) were relatively higher than the rapid heating curing (T2) accounting for 10, 2, 32 and 32% respectively, but there were no differences among treatments (P〉 0.05). The effect of different conditions of curing on the activities of enzymes related to carotenoids degradation were significant. The lipoxygenase, phenylalanine ammonialyase, peroxidase, and polyphenol oxidase enzymes had a bidirectional effect on the quality of tobacco leaves and it was beneficial to form more premise matter of aroma based on the higher enzyme activities at the early leaf-drying stage. The slow heating could regulate the change in various enzymes' activities reasonably, making cell redox reaction to reach the dynamic balance and make the degradation of carotenoids adequately. Meanwhile, it could avoid the occurrence of browning reaction and provide foundation for improving the quality of tobacco and optimization of technology for bulk curing and further enhancing aroma.展开更多
The possibility of applying steel slag as mineraladmixture in steam-cured concrete was investigated. Thecompressive strength, chloride permeability, carbonationdepth and drying shrinkage of concrete and the microstruc...The possibility of applying steel slag as mineraladmixture in steam-cured concrete was investigated. Thecompressive strength, chloride permeability, carbonationdepth and drying shrinkage of concrete and the microstructurecharacteristics of hardened paste were studied. Results showthat the steam-cured concrete containing steel slag at a highwater-to-binder ratio has low compressive strength, coarsepore structure, moderate permeability, large carbonation depthand great drying shrinkage. The negative effects of steel slagon the mechanical and durability performance of steam-curedconcrete become smaller at a low water-to-binder ratio or byadding ultrafine ground granulated blast furnace slag(UGGBS). The later-age hydration of cement is significantlypromoted by adding steel slag. The pozzolanic reaction andmicro-filler effect of UGGBS result in dense structure, whichmakes great contribution to the strength development anddurability performance of steam-cured concrete. These effectsof steel slag and UGGBS are significant at a low water tobinder ratio. The steam-cured concrete containing steel slag-UGGBS blended mineral admixture at a low water-to-binderratio has the best performance with high compressive strength,fine pore structure and good durability.展开更多
Ultra-violet(UV)curing is an efficient method for composite molding.Firstly,thermophysical properties of UV cured glass-fiber reinforced plastics are conducted.Material properties are studied for various kinds of post...Ultra-violet(UV)curing is an efficient method for composite molding.Firstly,thermophysical properties of UV cured glass-fiber reinforced plastics are conducted.Material properties are studied for various kinds of postcuring modes.Then the UV curing method is suggested in manufacturing V-crimp folded core for sandwich panels.Two kinds of processing schemes for V-crimp folded core manufacturing using UV curing are presented.Finally,the effect of post-curing on the mechanical properties of folded core sandwiches is experimentally studied,and optimum modes of post-curing are determined.The experimental results show that the ultimate compressive strength of the folded sandwiches is increased by 60% after post-curing with the optimum post-curing mode.展开更多
[ Objective] This study aimed to investigate the curing performance of polyurethane curing barn and reduce the cost of tobacco leaf flue-curing. [ Meth- odl The temperature control effect, curing effect and curing cos...[ Objective] This study aimed to investigate the curing performance of polyurethane curing barn and reduce the cost of tobacco leaf flue-curing. [ Meth- odl The temperature control effect, curing effect and curing cost of polyurethane curing barn and traditional bulk curing barn were analyzed and compared. [ Re- suit] The results showed that there were no significant differences in curing performance between two types of curing barns. Horizontal temperature differences in- creased slightly as the temperature rose. Specifically, horizontal temperature differences between each layer ranged from 0.2 ~C to 0.5 ~. Both two types of curing barns exhibited uniform air distribution. Polyurethane curing barn exhibited stable vertical temperature differences. Both two types of curing barns presented good curing effects with slight differences. Polyurethane curing barn exhibited higher economic benefits, lower coal cost, lower electricity cost, lower labor cost and lon- ger service life than traditional bulk curing barn, but its construction cost was higher. [ Conclusion] Polyurethane curing barn exhibits better curing performance with ~ood application prospects.展开更多
Electron beam (EB) curing of composites has many advantages. Heat-resistant EB-curing composites could substitute polyimide composites used in aeronautical engines. In this paper, the effects of catalyst and dose on t...Electron beam (EB) curing of composites has many advantages. Heat-resistant EB-curing composites could substitute polyimide composites used in aeronautical engines. In this paper, the effects of catalyst and dose on the cured resin were investigated. The heat-resistance of the resin cured by EB was evaluated by dynamic mechanical analysis (DMA). The experimental results show that the mechanical properties of the composites cured by EB could meet the specifications of aeronautical engines at 250 degreesC.展开更多
The radiative curable dendritic acrylated aromatic/aliphatic polyesters based on pentaerythritol, 1,2,4 benzenetricaboxylic anhydride and epoxy propane modified with acryloyl chloride were synthesized via a diver...The radiative curable dendritic acrylated aromatic/aliphatic polyesters based on pentaerythritol, 1,2,4 benzenetricaboxylic anhydride and epoxy propane modified with acryloyl chloride were synthesized via a divergent procedure, and their photopolymerization kinetics was studied by photo differential scanning calorimetry. The mechanical properties and the morphology of the fracture surface of the cured dendritic polyester films were investigated by means of dynamic mechanical thermal analysis and scanning electron microscopy, respectively.展开更多
The miscibility of the blend,composed of a bisphenol A epoxy resins (Diglycidyl ether of bisphenol A) (DGEBA) and poly(ethylene oxide) (PEG) and crosslinked by phthalic anhydride (PA) was studied using dynamic mechani...The miscibility of the blend,composed of a bisphenol A epoxy resins (Diglycidyl ether of bisphenol A) (DGEBA) and poly(ethylene oxide) (PEG) and crosslinked by phthalic anhydride (PA) was studied using dynamic mechanical method. Single glass transition temperatures intermediate between the two pure components were observed for all blend levels. The secondary relaxation mechanism should relate to not only diester linkage, but also hydroxyether structural unit in the system. Fourier transform infrared spectroscopy (FTIR) is applied to study the curing reaction and intermolecular specific interaction of the system. The results indicate the PEO participates the crosslinking reaction, accelerates the curing reaction and make the reaction more perfect. The shifts of the hydroxyl band and carbonyl band demonstrate the presence of the intermolecular interaction in the cured blend. Moreover, the molecular interaction between the side hydroxyl in the hydroxyether units and the ether bond in PEO macromolecules is stronger.展开更多
A kind of aziridine crosslinkers was synthesized and used to crosslink acrylate copolymers. The crosslinking properties and curing kinetics of the resin were studied. It was found that with the increase of the content...A kind of aziridine crosslinkers was synthesized and used to crosslink acrylate copolymers. The crosslinking properties and curing kinetics of the resin were studied. It was found that with the increase of the content of crosslinker in the emulsion, the mechanical properties and solvent resistance of the resin will be apparently improved, but its glass transition temperature (T.) is very low. The lowest amount of crosslinker used in the acrylic resin emulsion is 0.25%. Curing kinetics studied by DSC show that this curing reaction occurs readily because the apparent activation energy of the reaction is low (65.1 kJ/mol). These results demonstrate that the aziridine crosslinker is indeed a low temperature crosslinking agent and can be used at room temperature.展开更多
This study aims to determine the most convenient calcination temperature and calcination duration of wastestabilized Adobe(AB)to produce a new alkali-activated binder.Waste-stabilized Adobe mainly consists of soil,CaC...This study aims to determine the most convenient calcination temperature and calcination duration of wastestabilized Adobe(AB)to produce a new alkali-activated binder.Waste-stabilized Adobe mainly consists of soil,CaCO3 as a stabilizer,and straw(for strengthening).The availability of raw materials for making Adobe presents the waste-stabilized Adobe as a potential product for a new alkali-activated binder.Waste-stabilized Adobe collected from an abandoned damaged building in the village of Inonu in Northern Cyprus,ground and calcined at the following temperatures:450,550,650,750,850,and 950℃.The calcination at each temperature was held for different durations 1,3,5,and 7 h.Raw and calcined waste stabilized Adobe structures were investigated using XRF,TGA-DTA,XRD,FTIR,and SEM.Considering technical and environmental views related to energy consumption,waste stabilized Adobe calcined at 750℃ for 1 h presented the most promising results regarding the production of a new precursor for alkali-activated binder.This study also presents the effect of ground granulated blast furnace slag(GGBFS)usage on the fresh and hardened properties of optimum calcined AB-based alkali-activated pastes cured at room temperature.GGBFS was used to partially replace AB to form a binary composite raw material system and seven experimental groups were designed according to replacement levels of 0%,5%,10%,15%,20%,25%and 30%(by mass).Alkali-activated high volume waste-stabilized Adobe-slag pastes prepared using Na2SiO3-to-NaOH ratio of 2 and 12 M concentration of Sodium Hydroxide.The fresh property as flowability and the hardened property as the compressive strength of the alkali-activated pastes with different GGBFS contents were investigated.The results indicated that the incorporation of GGBFS increased the flowability of fresh alkali-activated pastes.A 28-day compressive strength of 43.75 MPa can be obtained by a 30%replacement level of GGBFS.展开更多
[Objectives]To explore the growth characteristics,nitrogen metabolism and curing characteristics of the new variety NC71 in strongly aromatic tobacco leaves production area.[Methods]With Yunyan 87 as the control and N...[Objectives]To explore the growth characteristics,nitrogen metabolism and curing characteristics of the new variety NC71 in strongly aromatic tobacco leaves production area.[Methods]With Yunyan 87 as the control and NC71 as the experimental material,the experiment was carried out in Nanyang tobacco area for two consecutive years to study the growth characteristics of tobacco plants,the activity of key enzymes in nitrogen metabolism,the content of secondary metabolites,and the differences of tobacco-related water content,PPO enzyme activity and total phenol content.[Results]NC71 plants had lower height,better appearance quality and lower nicotine,total sugar and chlorine content.NC71 high nitrogen treatment and Yunyan 87 medium nitrogen treatment had similar key enzyme activity of nitrogen metabolism,content of secondary metabolites;Yunyan 87 and NC71 were easy to cure and resistant to curing.[Conclusions]This study provides a reference for measuring the appropriate nitrogen application rate and optimizing the curing process from the activities of the key enzymes NR and GS in nitrogen metabolism at the mature stage of the variety.展开更多
Parkinson’s Disease (PD) is a chronic progressive degeneration disease of the central nervous system of extrapyramidal system. The main pathological changes are the degeneration of the substantia nigra striatum, lack...Parkinson’s Disease (PD) is a chronic progressive degeneration disease of the central nervous system of extrapyramidal system. The main pathological changes are the degeneration of the substantia nigra striatum, lack of dopamine in the brain, causing clinical performance: static tremor, muscle rigidity, slow movement and abnormal posture. It is one of the worldwide medical problems;at present, modern medicine thinks that PD is an incurable and permanent disease. However, in my long-term clinical work, I have cured many cases of PD patients by using Xifengzhizhan pills and Xifenzhizhan capsules, and I have found and proved that Chinese Medicine can cure PD.展开更多
An experimental investigation is conducted to evaluate the potential degradation in the mechanical properties of an epoxy resin and unidirectional glass fiber-reinforced epoxy (GFRE) as a result of exposure to fluctua...An experimental investigation is conducted to evaluate the potential degradation in the mechanical properties of an epoxy resin and unidirectional glass fiber-reinforced epoxy (GFRE) as a result of exposure to fluctuating temperature. A commonly used room-cured epoxy resin and the GFRE are subjected to various numbers of thermal cycles (up to 1000 heating/cooling cycles). Mechanical tests are conducted to examine the influence of thermal cycles on the stiffness, ultimate strength and strain of the resin and its GFRE. The Fourier transform-Raman spectroscopy (FT-Raman) is conducted to investigate the influence of the thermal cycles on the resulting chemical changes and curing degree of the resin. In addition, the Differential Scanning Calorimetry (DSC) analysis is conducted to investigate the variation in the glass transition temperature (Tg) of the resin as a function of the applied thermal cycles.展开更多
文摘The measures of steam curing and early-strengthening agents to promote the precast components to reach the target strength quickly can bring different degrees of damage to the concrete.Based on this,the new nanomaterial CSH-the hydration product of cement effectively solves these measures’disadvantages,such as excessive energy consumption,thermal stress damage,and the introduction of external ions.In this paper,the effect of CSH on the early strength of precast fly ash concrete components was investigated in terms of setting time,workability,and mechanical properties and analyzed at the microscopic level using hydration temperature,XRD,and SEM.The results showed that under the same workability,CSH could significantly reduce the amount of admixture,shorten the final setting time,almost not affect the initial setting time,and accelerate the hydration of cement.At the optimum dose of 5%,the mechanical properties of the specimens were improved by more than 98%within 12 h of hydration,resulting in an earlier release time of 12 h and no risk of strength inversion later.The results of this paper give theoretical support to the behavior of precast components under steam-free curing.
基金supported by ‘Follow-up Study of Retreatment TB Patients with Sputum Smear Positive Two Years after Declared Cured’(TB10-002)
文摘This study aimed to learn the recurrence rate in the retreatment TB patients with sputum smear and/or culture positive (ss+ and/or c+) two years after they were declared cured, and to explore causes of recurrence in order to improve long-time treatment outcome. 5 cities were selected as research locations. Recurrence of TB was judged by chest X-ray examination together with sputum smear and culture examination.
基金supported by Henan Province’s key R&D and promotion projects(scientific and technological research)projects(222102310587)Key Scientific Research Project Plan of Henan Province(22A310011)+4 种基金Grants from the Henan University(Yellow River Scholar Fund for Shanqing Zheng)the National Natural Science Foundation of China(81872584)Key R&D and Natural Science Foundation of Shenzhen(JCYJ20210324093211030)Medical Scientific Research Foundation of Guangdong Province(A2020490)the Interdisciplinary Research for First-class Discipline Construction Project of Henan University(2019YLXKJC04)。
文摘The aim of this work was to explore the physicochemical and structural properties,lipid oxidation and antioxidant capacity of the peptides extracted from Cantonese cured meat and as well as to investigate the effect of drying time on the sarcoplasmic and myofibrillar proteins of Cantonese cured meat.The results suggested that salting out,protein oxidation and heat treatment were closely related to surface hydrophobicity and the secondary structure of peptides was changed by processing.And the peroxide value and the value of tributyltin compounds were different in evaluating the degree of lipid oxidation.Glu and His were the major amino acid.The approximate molecular weights of the sarcoplasmic proteins and myofibrillar proteins ranged from 31 kDa to 50 kDa and 66 kDa,respectively.The results indicated that reducing the levels of protein oxidation and improvement of the antioxidant properties should be of great interest to preserve the nutritional quality of meat products and prolong preservation period.
文摘The main agronomic traits,economic traits,appearance quality,main chemical components,gas composition and physical parameters of 10 flue cured tobacco varieties were investigated in the experiment.And the field natural incidence of the main diseases was investigated.The results showed that main agronomic characters of the 10 varieties were in line with the breeding objectives,among which 5 varieties have good economic characters;5 varieties have good appearance quality;6 varieties have coordinated chemical composition and high potassium content;9 varieties have good smoke components and physical indicators.
文摘Foreword ISO(the International Organization for Standardization)is a worldwide federation of national standards bodies(ISO member bodies).The work of preparing International Standards is normally carried out through ISO technical committees.Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee.
文摘Objective To analyse infection rate of ventricular hemorrhage after lateral ventricle drainage and evaluate the method and measure of precaution. Methods Patients were divided into first and second groups according to the remaining time of drainage tube and into A and B groups according to drainage in one or two sides. After operation the infection condition of insert tube was observed and blood was cultivated regularly. Results The infection rate in the first group was significantly shorter than that in the second one (P 【 0. 01), while it was no significantly difference between groups A and B (P 】 0. 05). Conclusion To remain drainage tube for one to two weeks is safer than for more than two weeks. The infection rate is higher in group with drainage in two sides than in one. In addition, it is obviously related to the patient’s body condition and immunity. 6 refs,2 tabs.
文摘A new method concerning with the simultaneous reinforcing and toughening of polypropylene (PP) was reported. Dynamical cure of the epoxy resin was successfully applied in the PP/maleic anhydride-grafted styrene-ethylene-butylene-styrene (SEBS) triblock copolymer, and the obtained blends named as dynamically cured PP/MAH-g-SEBS/epoxy blends. The stiffness and toughness of the blends are in a good balance, and MAH-g-SEBS was acted as not only an impact modifier but also a compatibilizer. The structure of the dynamically cured PP/MAH-g-SEBS/epoxy blends is the embedding of the epoxy particles by the MAH-g- SEBS.C2009 Xue Liang Jiang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金supported by the Key Project of State Tobacco Monoply Administration of China(3300806156)
文摘The mechanism of carotenoid degradation and the changes in the activities of related enzymes in flue-cured tobacco at the leaf-drying stage during the bulk-curing process were studied in order to provide theoretical basis for optimization of curing technology. The effect of different rising speeds of temperature on the carotenoid degradation and the related enzymes activities at the color-fixing stage during the bulk curing process was studied by using the electric-heated fluecuring barn designed by Henan Agricultural University, China, based on curing technology with yellowing at low temperature and moderate humidity and leaf drying at moderate humidity. The results showed that the carotenoid degradation components (β-carotene, lutein, neoxanthin, and violaxthin) decreased gradually at the color-fixing stage during the bulk curing process. The carotenoid degradation components viz.,β-carotene, lutein, neoxanthin, and violaxthin at the slow heating curing (T1) were relatively higher than the rapid heating curing (T2) accounting for 10, 2, 32 and 32% respectively, but there were no differences among treatments (P〉 0.05). The effect of different conditions of curing on the activities of enzymes related to carotenoids degradation were significant. The lipoxygenase, phenylalanine ammonialyase, peroxidase, and polyphenol oxidase enzymes had a bidirectional effect on the quality of tobacco leaves and it was beneficial to form more premise matter of aroma based on the higher enzyme activities at the early leaf-drying stage. The slow heating could regulate the change in various enzymes' activities reasonably, making cell redox reaction to reach the dynamic balance and make the degradation of carotenoids adequately. Meanwhile, it could avoid the occurrence of browning reaction and provide foundation for improving the quality of tobacco and optimization of technology for bulk curing and further enhancing aroma.
基金Postdoctoral Science Foundation of China(No.2015M580992,2016T90036)the Open Fund of State Key Laboratory of High Performance Civil Engineering Materials(No.2015CEM010)
文摘The possibility of applying steel slag as mineraladmixture in steam-cured concrete was investigated. Thecompressive strength, chloride permeability, carbonationdepth and drying shrinkage of concrete and the microstructurecharacteristics of hardened paste were studied. Results showthat the steam-cured concrete containing steel slag at a highwater-to-binder ratio has low compressive strength, coarsepore structure, moderate permeability, large carbonation depthand great drying shrinkage. The negative effects of steel slagon the mechanical and durability performance of steam-curedconcrete become smaller at a low water-to-binder ratio or byadding ultrafine ground granulated blast furnace slag(UGGBS). The later-age hydration of cement is significantlypromoted by adding steel slag. The pozzolanic reaction andmicro-filler effect of UGGBS result in dense structure, whichmakes great contribution to the strength development anddurability performance of steam-cured concrete. These effectsof steel slag and UGGBS are significant at a low water tobinder ratio. The steam-cured concrete containing steel slag-UGGBS blended mineral admixture at a low water-to-binderratio has the best performance with high compressive strength,fine pore structure and good durability.
基金supported by the Ministry of Education and Science of Russian Federation (No.RFMEFI57414X0078)
文摘Ultra-violet(UV)curing is an efficient method for composite molding.Firstly,thermophysical properties of UV cured glass-fiber reinforced plastics are conducted.Material properties are studied for various kinds of postcuring modes.Then the UV curing method is suggested in manufacturing V-crimp folded core for sandwich panels.Two kinds of processing schemes for V-crimp folded core manufacturing using UV curing are presented.Finally,the effect of post-curing on the mechanical properties of folded core sandwiches is experimentally studied,and optimum modes of post-curing are determined.The experimental results show that the ultimate compressive strength of the folded sandwiches is increased by 60% after post-curing with the optimum post-curing mode.
基金Supported by Project of Zunyi Tobacco Company[ZYJ(2014)No.201407]
文摘[ Objective] This study aimed to investigate the curing performance of polyurethane curing barn and reduce the cost of tobacco leaf flue-curing. [ Meth- odl The temperature control effect, curing effect and curing cost of polyurethane curing barn and traditional bulk curing barn were analyzed and compared. [ Re- suit] The results showed that there were no significant differences in curing performance between two types of curing barns. Horizontal temperature differences in- creased slightly as the temperature rose. Specifically, horizontal temperature differences between each layer ranged from 0.2 ~C to 0.5 ~. Both two types of curing barns exhibited uniform air distribution. Polyurethane curing barn exhibited stable vertical temperature differences. Both two types of curing barns presented good curing effects with slight differences. Polyurethane curing barn exhibited higher economic benefits, lower coal cost, lower electricity cost, lower labor cost and lon- ger service life than traditional bulk curing barn, but its construction cost was higher. [ Conclusion] Polyurethane curing barn exhibits better curing performance with ~ood application prospects.
文摘Electron beam (EB) curing of composites has many advantages. Heat-resistant EB-curing composites could substitute polyimide composites used in aeronautical engines. In this paper, the effects of catalyst and dose on the cured resin were investigated. The heat-resistance of the resin cured by EB was evaluated by dynamic mechanical analysis (DMA). The experimental results show that the mechanical properties of the composites cured by EB could meet the specifications of aeronautical engines at 250 degreesC.
基金Supported by the National Natural Science Foundation of China(No. 2 0 0 74 0 34)
文摘The radiative curable dendritic acrylated aromatic/aliphatic polyesters based on pentaerythritol, 1,2,4 benzenetricaboxylic anhydride and epoxy propane modified with acryloyl chloride were synthesized via a divergent procedure, and their photopolymerization kinetics was studied by photo differential scanning calorimetry. The mechanical properties and the morphology of the fracture surface of the cured dendritic polyester films were investigated by means of dynamic mechanical thermal analysis and scanning electron microscopy, respectively.
基金This study is partially supported by the National Natural Science Foundation of China.
文摘The miscibility of the blend,composed of a bisphenol A epoxy resins (Diglycidyl ether of bisphenol A) (DGEBA) and poly(ethylene oxide) (PEG) and crosslinked by phthalic anhydride (PA) was studied using dynamic mechanical method. Single glass transition temperatures intermediate between the two pure components were observed for all blend levels. The secondary relaxation mechanism should relate to not only diester linkage, but also hydroxyether structural unit in the system. Fourier transform infrared spectroscopy (FTIR) is applied to study the curing reaction and intermolecular specific interaction of the system. The results indicate the PEO participates the crosslinking reaction, accelerates the curing reaction and make the reaction more perfect. The shifts of the hydroxyl band and carbonyl band demonstrate the presence of the intermolecular interaction in the cured blend. Moreover, the molecular interaction between the side hydroxyl in the hydroxyether units and the ether bond in PEO macromolecules is stronger.
文摘A kind of aziridine crosslinkers was synthesized and used to crosslink acrylate copolymers. The crosslinking properties and curing kinetics of the resin were studied. It was found that with the increase of the content of crosslinker in the emulsion, the mechanical properties and solvent resistance of the resin will be apparently improved, but its glass transition temperature (T.) is very low. The lowest amount of crosslinker used in the acrylic resin emulsion is 0.25%. Curing kinetics studied by DSC show that this curing reaction occurs readily because the apparent activation energy of the reaction is low (65.1 kJ/mol). These results demonstrate that the aziridine crosslinker is indeed a low temperature crosslinking agent and can be used at room temperature.
文摘This study aims to determine the most convenient calcination temperature and calcination duration of wastestabilized Adobe(AB)to produce a new alkali-activated binder.Waste-stabilized Adobe mainly consists of soil,CaCO3 as a stabilizer,and straw(for strengthening).The availability of raw materials for making Adobe presents the waste-stabilized Adobe as a potential product for a new alkali-activated binder.Waste-stabilized Adobe collected from an abandoned damaged building in the village of Inonu in Northern Cyprus,ground and calcined at the following temperatures:450,550,650,750,850,and 950℃.The calcination at each temperature was held for different durations 1,3,5,and 7 h.Raw and calcined waste stabilized Adobe structures were investigated using XRF,TGA-DTA,XRD,FTIR,and SEM.Considering technical and environmental views related to energy consumption,waste stabilized Adobe calcined at 750℃ for 1 h presented the most promising results regarding the production of a new precursor for alkali-activated binder.This study also presents the effect of ground granulated blast furnace slag(GGBFS)usage on the fresh and hardened properties of optimum calcined AB-based alkali-activated pastes cured at room temperature.GGBFS was used to partially replace AB to form a binary composite raw material system and seven experimental groups were designed according to replacement levels of 0%,5%,10%,15%,20%,25%and 30%(by mass).Alkali-activated high volume waste-stabilized Adobe-slag pastes prepared using Na2SiO3-to-NaOH ratio of 2 and 12 M concentration of Sodium Hydroxide.The fresh property as flowability and the hardened property as the compressive strength of the alkali-activated pastes with different GGBFS contents were investigated.The results indicated that the incorporation of GGBFS increased the flowability of fresh alkali-activated pastes.A 28-day compressive strength of 43.75 MPa can be obtained by a 30%replacement level of GGBFS.
基金Supported by Key Project of Nanping Tobacco Company of Fujian Province(NYK2021-09-03)Key Project of Tongren Tobacco Company of Guizhou Province(202101).
文摘[Objectives]To explore the growth characteristics,nitrogen metabolism and curing characteristics of the new variety NC71 in strongly aromatic tobacco leaves production area.[Methods]With Yunyan 87 as the control and NC71 as the experimental material,the experiment was carried out in Nanyang tobacco area for two consecutive years to study the growth characteristics of tobacco plants,the activity of key enzymes in nitrogen metabolism,the content of secondary metabolites,and the differences of tobacco-related water content,PPO enzyme activity and total phenol content.[Results]NC71 plants had lower height,better appearance quality and lower nicotine,total sugar and chlorine content.NC71 high nitrogen treatment and Yunyan 87 medium nitrogen treatment had similar key enzyme activity of nitrogen metabolism,content of secondary metabolites;Yunyan 87 and NC71 were easy to cure and resistant to curing.[Conclusions]This study provides a reference for measuring the appropriate nitrogen application rate and optimizing the curing process from the activities of the key enzymes NR and GS in nitrogen metabolism at the mature stage of the variety.
文摘Parkinson’s Disease (PD) is a chronic progressive degeneration disease of the central nervous system of extrapyramidal system. The main pathological changes are the degeneration of the substantia nigra striatum, lack of dopamine in the brain, causing clinical performance: static tremor, muscle rigidity, slow movement and abnormal posture. It is one of the worldwide medical problems;at present, modern medicine thinks that PD is an incurable and permanent disease. However, in my long-term clinical work, I have cured many cases of PD patients by using Xifengzhizhan pills and Xifenzhizhan capsules, and I have found and proved that Chinese Medicine can cure PD.
文摘An experimental investigation is conducted to evaluate the potential degradation in the mechanical properties of an epoxy resin and unidirectional glass fiber-reinforced epoxy (GFRE) as a result of exposure to fluctuating temperature. A commonly used room-cured epoxy resin and the GFRE are subjected to various numbers of thermal cycles (up to 1000 heating/cooling cycles). Mechanical tests are conducted to examine the influence of thermal cycles on the stiffness, ultimate strength and strain of the resin and its GFRE. The Fourier transform-Raman spectroscopy (FT-Raman) is conducted to investigate the influence of the thermal cycles on the resulting chemical changes and curing degree of the resin. In addition, the Differential Scanning Calorimetry (DSC) analysis is conducted to investigate the variation in the glass transition temperature (Tg) of the resin as a function of the applied thermal cycles.