The pressure drop during production in the near-wellbore zone of gas condensate reservoirs causes condensate formation in this area.Condensate blockage in this area causes an additional pressure drop that weakens the ...The pressure drop during production in the near-wellbore zone of gas condensate reservoirs causes condensate formation in this area.Condensate blockage in this area causes an additional pressure drop that weakens the effective parameters of production,such as permeability.Reservoir rock wettability alteration to gas-wet through chemical treatment is one of the solutions to produce these condensates and eliminate condensate blockage in the area.In this study,an anionic fluorinated surfactant was synthesized and used for chemical treatment and carbonate rock wettability alteration.The synthesized surfactant was characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis.Then,using surface tension tests,its critical micelle concentration(CMC)was determined.Contact angle experiments on chemically treated sections with surfactant solutions and spontaneous imbibition were performed to investigate the wettability alteration.Surfactant adsorption on porous media was calculated using flooding.Finally,the surfactant foamability was investigated using a Ross-Miles foam generator.According to the results,the synthesized surfactant has suitable thermal stability for use in gas condensate reservoirs.A CMC of 3500 ppm was obtained for the surfactant based on the surface tension experiments.Contact angle experiments show the ability of the surfactant to chemical treatment and wettability alteration of carbonate rocks to gas-wet so that at the constant concentration of CMC and at 373 K,the contact angles at treatment times of 30,60,120 and 240 min were obtained 87.94°,93.50°,99.79°and 106.03°,respectively.However,this ability varies at different surfactant concentrations and temperatures.The foamability test also shows the suitable stability of the foam generated by the surfactant,and a foam half-life time of 13 min was obtained for the surfactant at CMC.展开更多
It is very important to clarify the relationship of changes of molecular combinations in wood cell walls and the chemical rheological behavior during various chemical reagent treatments, for it would be helpful to dev...It is very important to clarify the relationship of changes of molecular combinations in wood cell walls and the chemical rheological behavior during various chemical reagent treatments, for it would be helpful to develop new wood modification technologies and to enrich the theory of chemical rheology of wood. Based on previous investigations on the chemorheological properties of wood by chemical treatments and the applied methods in chemical rheology of wool fibers, this paper proposes the study of various additional reagents to wood saturated in water for long periods of time in order to investigate the chemical rheology of wood, which can provide information about the character of combinations between wood molecules and the structural changes of molecules and further put forward the idea of modifying wood in a decrystallized state.展开更多
Effect of Ti(iso-C3H7O)4 treatment on the photoinduced charge carrier kinetics of nanocrystalline porous TiO2 films is studied by time-resolved microwave conductivity measurements. Analysis of the transient photocond...Effect of Ti(iso-C3H7O)4 treatment on the photoinduced charge carrier kinetics of nanocrystalline porous TiO2 films is studied by time-resolved microwave conductivity measurements. Analysis of the transient photoconductivity decays indicates that Ti(iso-C3H7O)4 treatment leads to an increased concentration of photogenerated charge carriers and a fast interfacial transfer rate of holes via the surface modification of the freshly growing TiO2 nanocrystallites.展开更多
AFM has been utilized to study the surface topography and the local conductivity of nanocrystalline TiO2 films. Improving the local conductivity by Ti(iso-C3H7O)4 treatment is characterized by quantitative analysis o...AFM has been utilized to study the surface topography and the local conductivity of nanocrystalline TiO2 films. Improving the local conductivity by Ti(iso-C3H7O)4 treatment is characterized by quantitative analysis of the simultaneous current image. The mechanism of Ti(iso C3H7O)4 treatment is discussed.展开更多
Multi-walled carbon nanombes with homogeneous diameters （40 - 60 nm）, produced by chemical vapor deposition of hydrocarbon gas, are purified by nitric acids. Infrared and Raman studies indicate that oxygen containin...Multi-walled carbon nanombes with homogeneous diameters （40 - 60 nm）, produced by chemical vapor deposition of hydrocarbon gas, are purified by nitric acids. Infrared and Raman studies indicate that oxygen containing surface groups, which are predominately carboxylic, phenolic and lactonic groups, are introduced into purified carbon nanotubes. Then three kinds of block-form porous tablets of carbon nanotubes are fabricated as electrodes in electrochemical double-layer capacitors. Using mounded mixture comprising carbon nanotubes and binder powders provides these tablets. Comparison of the effect of different processing on the structural performance of the capacitors is specifically investigated. Using chemically treated electrodes, electrochemical double-layer capacitors with a specific capacitance of about 33 F/g are obtained with 38 wt % H2SO4 as the electrolyte.展开更多
P. tritici-repentis, B. graminb and C. sativus are important diseases of spring wheat in Estonia. Field trials were carried out during 2006 and 2008 in JiSgeva PBI. Two kinds of treatments were used： Tl consisted of ...P. tritici-repentis, B. graminb and C. sativus are important diseases of spring wheat in Estonia. Field trials were carried out during 2006 and 2008 in JiSgeva PBI. Two kinds of treatments were used： Tl consisted of four different rates of basic fertilizer： NO = NOPOK0; N1 = N60P13K23, N2 = N 100P22K39; N3 = N140P31K54 kg ha^-1. T2 treatment consisted of same rates of basic fertilizers and in addition growth regulator, fungicides and leaf fertilizers. Seeds of the varieties ＂Monsun＂ and ＂Vinjett＂ were untreated. Results of the effects of fertilizers on the infections of fungal diseases on spring wheat monoculture revealed that test years had the biggest influence on infection intensity of B. graminis （REy = 50.7-59.2） in T1 and T2 and P. tritici-repentis in T2 （REy = 31.6）, whereas infection of C. sativus was more dependent on year in Tl （R2y = 37.3）. Yield correlated highly with a fertilizer rate and year. In the treatment T2, the yield depended more on weather conditions （REy = 40.7） and in T1, the yield was more dependent on fertilization rate （REF = 60.2）. We found TI to be more economic as the optimum N rate varied from N60 to N100 kg hat and the benefit in monetary terms raised from 297ε hal （＂Monsun＂ 2007） to 9056 hal （＂Vinjett＂ 2008）. In T2, N rate 60 kg ha^-1 raised the monetary benefit from 806 ha^-1 （＂Monsun＂ 2007） to 731ε ha^-1 （＂Vinjett＂ 2008）. The highest economic profit was gained by using low rates of fertilizer for ＂Monsun＂ and the highest rates of fertilizer for ＂Vinjett＂.展开更多
Background Silicon gel is unfavourable for cell attachment and growth. This study was to study if pretreating the surface of silicon gel with chemical agents affects the proliferation of epithelial cells Methods Si...Background Silicon gel is unfavourable for cell attachment and growth. This study was to study if pretreating the surface of silicon gel with chemical agents affects the proliferation of epithelial cells Methods Silicon gel was made and treated with either mixed acid solution (containing 232 g/dm 3 of H 2SO 4 and 8 g/dm 3 of K 2Cr 2O 7) or 300 cm 3/dm 3 peroxide for 5, 10, and 15 minutes or 10, 15, and 20 minutes, respectively The cultured corneal epithelial cells were seeded onto those silicon gels and kept for 13 days Immunohistochemical investigations were then carried out for integrin (alpha 6 or beta 4) and actin KH*2/5DResults Growth of the epithelial cells in silicon gels treated with mixed acid solution for 10 minutes and 15 minutes was much significant than that in the untreated gels After a 12-hour culture, a small number of corneal epithelial cells were proliferated on the surface of the silicon gels that had been treated with peroxide for 15 minutes After a 3-day culture, those cells were further proliferated and fused together The corneal epithelial cells did not grow well in the silicon gels treated with peroxide for 10 or 20 minutes Immunostaining revealed the expression of actin and integrin alpha 6 or beta 4 on the silicon gels that were treated with mixed acid solution for 10 minutes or peroxide for 15 minutes Conclusion Silicon gels treated either with mixed acid solution for 10 or 15 minutes or with peroxide for 15 minutes improves cell proliferation展开更多
With the progress of ULSI technology, materials with low dielectric constant are required to replace SiO2 film as the interlayer to scale down the interconnection delay. Fluorinated Si oxide thin films (SiOF) are a pr...With the progress of ULSI technology, materials with low dielectric constant are required to replace SiO2 film as the interlayer to scale down the interconnection delay. Fluorinated Si oxide thin films (SiOF) are a promising material for the low dielectric constant and the process compatibility in existing technology. However, SiOF films are liable to absorb moisture when exposed to air. By treating the SiOF films with O-2 plasma, it was found that the moisture resistibility of SiOF films was remarkably improved. The mechanism of the improvement in stability of dielectric constant was investigated. The results show that: 1) F atoms dissociated from the films and the bond angle of Si-O-Si decreased. 2) The plasma treatment enhanced the strength of Si-F bonds by removing unstable =SiF2 structures in the films. Resistibility of SiOF films in moisture was improved.展开更多
This paper is aimed to show the influence of initial chemical pretreatment prior to subsequent plasma activation of aluminum surfaces.The results of our study showed that the state of the topmost surface layer（i.e.th...This paper is aimed to show the influence of initial chemical pretreatment prior to subsequent plasma activation of aluminum surfaces.The results of our study showed that the state of the topmost surface layer（i.e.the surface morphology and chemical groups）of plasma modified aluminum significantly depends on the chemical precleaning.Commonly used chemicals（isopropanol,trichlorethane,solution of Na OH in deionized water）were used as precleaning agents.The plasma treatments were done using a radio frequency driven atmospheric pressure plasma pencil developed at Masaryk University,which operates in Ar,Ar/O_2 gas mixtures.The effectiveness of the plasma treatment was estimated by the wettability measurements,showing high wettability improvement already after 0.3 s treatment.The effects of surface cleaning（hydrocarbon removal）,surface oxidation and activation（generation of OH groups）were estimated using infrared spectroscopy.The changes in the surface morphology were measured using scanning electron microscopy.Optical emission spectroscopy measurements in the near-to-surface region with temperature calculations showed that plasma itself depends on the sample precleaning procedure.展开更多
Birdsfoot trefoil （Lotus corniculatus L.） is high in nutritional value and adapted to slightly acidic, droughty, infertile, or wet soils. However, the impermeable seed coat restricts water imbibition and results in ...Birdsfoot trefoil （Lotus corniculatus L.） is high in nutritional value and adapted to slightly acidic, droughty, infertile, or wet soils. However, the impermeable seed coat restricts water imbibition and results in poor seed germination and subse- quent stand establishment. The aim of this study was to identify the dormancy mechanism of Birdsfoot trefoil seeds, and investigate the suitable pretreatment to overcome the poor seed germination. Germination behavior was characterized by using the final germination percentage and the mean germination time. The results indicated that coat thickness of dormant seeds was significant larger. The average hard seed rate was up to 92.3%. It was found that mechanical scarification, chemi- cal scarification with concentrated sulfuric acid （98% H_2SO_4）, and gibberellic acid soaking following freezing below zero temperature were effective in reducing hard- seededness and lead to increases of seed germination.展开更多
Experiments were carried out to study the removal of heavy metals from municipal sewage sludge by proper method for land application. The sequential extractions for metal fractionation showed that the non digested slu...Experiments were carried out to study the removal of heavy metals from municipal sewage sludge by proper method for land application. The sequential extractions for metal fractionation showed that the non digested sludge from Guangzhou contained Cu and Zn principally bound to carbonate and oxides and the metal sulfides were low. Among H 2SO 4, EDTA and NH 4HCO 3 extractant agents, H 2SO 4 was the most efficient and economic in removing the heavy metals, especially with the addition of the concentrated acid. Plant experiment in pots with Chinese cabbage ( Brassica Chinensis ) showed that the acidified sludges neutralized with alkaline amendments such as phosphate rock could increase significantly the plant yield and decreased the soil and plant contamination by heavy metals originated from sewage sludge.展开更多
In order to clarify the relationship between the microstructural changes and the rheological behaviors of four chemically treated woods (delignified wood, hemicellulose-removed wood, DMSO swollen and decrystallization...In order to clarify the relationship between the microstructural changes and the rheological behaviors of four chemically treated woods (delignified wood, hemicellulose-removed wood, DMSO swollen and decrystallization treated wood), the stress relaxation of wood with three different moisture contents was determined during periodic temperature changes. The experi- mental results show that after wood relaxation for 4 h at 25 °C, the stress decays sharply when the temperature increases and 2 h later the stress recovers again when the temperature drops back to the original point. The additional stress relaxation, produced after tem- perature begins to increase, is mainly caused by the thermal swelling, molecular thermal movement and the break of a part of residual hydrogen bonds. The number of hydrogen bonds and the size and amount of cavities in various treated woods greatly affect the magnitude of the additional relaxed stress and the recovery stress.展开更多
In order to clarify the effect of drying on structural changes of DMSO swell treated and DEA-SO2-DMSO decrystallization treated Chinese fir （Cunninghamia lanceolate） wood, the stress relaxation of treated oven-dry s...In order to clarify the effect of drying on structural changes of DMSO swell treated and DEA-SO2-DMSO decrystallization treated Chinese fir （Cunninghamia lanceolate） wood, the stress relaxation of treated oven-dry specimens during the processes of temperature elevation and reduction and that of treated wet specimens at constant temperature were determined. A stress decrease process and a stress increase process were observed in all stress ratio curves of wood during the processes of decreasing temperature. Untreated wood, during the process of temperature reduction under higher initial temperature conditions and during the process of temperature elevation, has a larger stress decrease than treated woods. In a wet state this trend is reversed. It indicated that the drying set made treated woods have a smaller increase in fluidity of wood constituents with increasing temperature. Some bonding between decrystallization reagents and wood molecules may occur.展开更多
The objective of this work is to carry out the chemical treatment for the hemp fabrics in a closed vacuum system and to prepare bio-based composites using treated hemp fabrics.The change in surface tension of the trea...The objective of this work is to carry out the chemical treatment for the hemp fabrics in a closed vacuum system and to prepare bio-based composites using treated hemp fabrics.The change in surface tension of the treated fabrics was measured using contact angle measurement and the wetting behavior using a tensiometer.Bio-based composites were fabricated using bio-based epoxy resin and different chemically treated fabrics.The flexural strength and dynamic water absorption behavior of the composites were characterized.The acetylated fabrics showed very good wetting behavior,and the contact angle values were marginally low compared to other treatment techniques.The bio-based composites fabricated using maleic anhydride treated fabrics achieved the flexural strength of 148 MPa and the dynamic water absorption values were less than 6%.The acetylated and maleic anhydride treatment methods were effective chemical treatments for the hemp fabrics and they enhanced both the wettability and fiber-matrix interaction.The chemical treatment methods that are carried out in the sealed environment can be utilized for all other natural fabrics that help overcome the moisture absorption behavior.展开更多
Each year, ethanol production is increasing in Brazil, consequently, the generation of byproducts as well. Among these, the vinasse stands out. With polluting power a hundred times greater than domestic sewage and hig...Each year, ethanol production is increasing in Brazil, consequently, the generation of byproducts as well. Among these, the vinasse stands out. With polluting power a hundred times greater than domestic sewage and high concentration of minerals, vinasse is generated in large volumes. Because of these characteristics, it is widely used in fertirrigation. However, it is composed of about 97% water, inflating the cost of the transport from the plant to the field. For these reasons, removing water from the vinasse and the consequent concentration of solids is an alternative management and application of this by-product. This project aimed to analyze the efficiency of various physical and chemical processes in the removal of water from the vinasse.展开更多
The particle characterization from the influent and effluent of a chemical-biological flocculation （CBF） process was studied with a laser diffraction device. Water samples from a chemically enhanced primary treatme...The particle characterization from the influent and effluent of a chemical-biological flocculation （CBF） process was studied with a laser diffraction device. Water samples from a chemically enhanced primary treatment （CEPT） process and a primary sediment tank process were also analyzed for comparison. The results showed that CBF process was not only effective for both the big size particles and small size particles removal, but also the best particle removal process in the three processes. The results also indicated that CBF process was superior to CEPT process in the heavy metals removal. The high and non-selective removal for heavy metals might be closely related to its strong ability to eliminate small particles. Samples from different locations in CBF reactors showed that small particles were easier to aggregate into big ones and those disrupted flocs could properly flocculate again along CBF reactor because of the biological flocculation.展开更多
The influences of chromium-free chemical conversion treatment and anodizing treatment on bonding strength of AZ31 magnesium alloy were studied by lap-shear test, SEM and electrochemical methods. Both chemical conversi...The influences of chromium-free chemical conversion treatment and anodizing treatment on bonding strength of AZ31 magnesium alloy were studied by lap-shear test, SEM and electrochemical methods. Both chemical conversion treatment and anodizing can increase the bonding strength. The anodizing treatment gives higher bonding strength and better corrosion resistance than chemical conversion treatment. The increase of bonding strength by the treatmetlts may be attributed to the uneven surface structures with micro-pores, resulting in increased bonding areas and the embedding effect.展开更多
This paper studies a compound treatment. i. e. liquid S , N,C co-diffusing with rare earth (RE) and then oxidization , for hot-working die steels , and the effect of RE on thermal fatigue behavior of the diffused laye...This paper studies a compound treatment. i. e. liquid S , N,C co-diffusing with rare earth (RE) and then oxidization , for hot-working die steels , and the effect of RE on thermal fatigue behavior of the diffused layer. XRD and SEM energy spectrum prove that trace RE element actually penetrates into the surface layer of steels. The result shows that RE can reduce the gradient of change of hardness in diffused layer, improve the morphology and distribution of compounds , and reduce the degree of surface alligator crack for thermal fatigue. The behavior of thermal fatigue of hot-working die steels is raised by 70% or so after the application of RE. The effect of RE is analysed according to the theory.展开更多
The accumulation of generated chemical wastes posed a serious problem for the UP College of Pharmacy. The faculty from the Department of Pharmaceutical Chemistry devised a scheme for the identification and segregation...The accumulation of generated chemical wastes posed a serious problem for the UP College of Pharmacy. The faculty from the Department of Pharmaceutical Chemistry devised a scheme for the identification and segregation of the chemical wastes and created a system for proper disposal of future chemical wastes. There were a total of 1,142 of accumulated chemical waste bottles, 804 of which were subjected to identification and segregation procedures. The wastes were preliminarily tested for its solubility/miscibility in water and acidity or basicity. The identification was done by qualitative tests for cyanide, sulfide, halogenated, non-halogenated, oxidizing, nitro, and heavy metal compounds. The final segregation was based on the presence of the most hazardous component or on pH and water-miscibility. The Department then developed and implemented a scheme for the proper disposal of the chemical wastes generated in laboratory experiments done in the College. Laboratory experiments were also modified to use less toxic and less amounts of chemicals.展开更多
文摘The pressure drop during production in the near-wellbore zone of gas condensate reservoirs causes condensate formation in this area.Condensate blockage in this area causes an additional pressure drop that weakens the effective parameters of production,such as permeability.Reservoir rock wettability alteration to gas-wet through chemical treatment is one of the solutions to produce these condensates and eliminate condensate blockage in the area.In this study,an anionic fluorinated surfactant was synthesized and used for chemical treatment and carbonate rock wettability alteration.The synthesized surfactant was characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis.Then,using surface tension tests,its critical micelle concentration(CMC)was determined.Contact angle experiments on chemically treated sections with surfactant solutions and spontaneous imbibition were performed to investigate the wettability alteration.Surfactant adsorption on porous media was calculated using flooding.Finally,the surfactant foamability was investigated using a Ross-Miles foam generator.According to the results,the synthesized surfactant has suitable thermal stability for use in gas condensate reservoirs.A CMC of 3500 ppm was obtained for the surfactant based on the surface tension experiments.Contact angle experiments show the ability of the surfactant to chemical treatment and wettability alteration of carbonate rocks to gas-wet so that at the constant concentration of CMC and at 373 K,the contact angles at treatment times of 30,60,120 and 240 min were obtained 87.94°,93.50°,99.79°and 106.03°,respectively.However,this ability varies at different surfactant concentrations and temperatures.The foamability test also shows the suitable stability of the foam generated by the surfactant,and a foam half-life time of 13 min was obtained for the surfactant at CMC.
基金Supported by the National Natural Science Foundation of China (Grant No.30070606) and Graduate Cultivation Foundation of Beijing Forestry University (Grant No.304)
文摘It is very important to clarify the relationship of changes of molecular combinations in wood cell walls and the chemical rheological behavior during various chemical reagent treatments, for it would be helpful to develop new wood modification technologies and to enrich the theory of chemical rheology of wood. Based on previous investigations on the chemorheological properties of wood by chemical treatments and the applied methods in chemical rheology of wool fibers, this paper proposes the study of various additional reagents to wood saturated in water for long periods of time in order to investigate the chemical rheology of wood, which can provide information about the character of combinations between wood molecules and the structural changes of molecules and further put forward the idea of modifying wood in a decrystallized state.
基金This work was supported by National Research Fund for Fundamental Key Project(G2000028205)Innovative Foundation of Chinese Academy of Sciences(KGCX2-303-02)the Project of the National Natural Science Foundation of China(29873057).
文摘Effect of Ti(iso-C3H7O)4 treatment on the photoinduced charge carrier kinetics of nanocrystalline porous TiO2 films is studied by time-resolved microwave conductivity measurements. Analysis of the transient photoconductivity decays indicates that Ti(iso-C3H7O)4 treatment leads to an increased concentration of photogenerated charge carriers and a fast interfacial transfer rate of holes via the surface modification of the freshly growing TiO2 nanocrystallites.
基金This work was supported by National Research Fund for Fundamental Key Project (G2000028205) Innovative Foundation of Chinese Academy of Sciences and the Project of the National Natural Science Foundation of China (29873057). We thank Dr. D.S. Zhang for
文摘AFM has been utilized to study the surface topography and the local conductivity of nanocrystalline TiO2 films. Improving the local conductivity by Ti(iso-C3H7O)4 treatment is characterized by quantitative analysis of the simultaneous current image. The mechanism of Ti(iso C3H7O)4 treatment is discussed.
基金Project supported by National High-Technology Research and De-velopment Program(Grant No .863 -2002AA302302)
文摘Multi-walled carbon nanombes with homogeneous diameters （40 - 60 nm）, produced by chemical vapor deposition of hydrocarbon gas, are purified by nitric acids. Infrared and Raman studies indicate that oxygen containing surface groups, which are predominately carboxylic, phenolic and lactonic groups, are introduced into purified carbon nanotubes. Then three kinds of block-form porous tablets of carbon nanotubes are fabricated as electrodes in electrochemical double-layer capacitors. Using mounded mixture comprising carbon nanotubes and binder powders provides these tablets. Comparison of the effect of different processing on the structural performance of the capacitors is specifically investigated. Using chemically treated electrodes, electrochemical double-layer capacitors with a specific capacitance of about 33 F/g are obtained with 38 wt % H2SO4 as the electrolyte.
文摘P. tritici-repentis, B. graminb and C. sativus are important diseases of spring wheat in Estonia. Field trials were carried out during 2006 and 2008 in JiSgeva PBI. Two kinds of treatments were used： Tl consisted of four different rates of basic fertilizer： NO = NOPOK0; N1 = N60P13K23, N2 = N 100P22K39; N3 = N140P31K54 kg ha^-1. T2 treatment consisted of same rates of basic fertilizers and in addition growth regulator, fungicides and leaf fertilizers. Seeds of the varieties ＂Monsun＂ and ＂Vinjett＂ were untreated. Results of the effects of fertilizers on the infections of fungal diseases on spring wheat monoculture revealed that test years had the biggest influence on infection intensity of B. graminis （REy = 50.7-59.2） in T1 and T2 and P. tritici-repentis in T2 （REy = 31.6）, whereas infection of C. sativus was more dependent on year in Tl （R2y = 37.3）. Yield correlated highly with a fertilizer rate and year. In the treatment T2, the yield depended more on weather conditions （REy = 40.7） and in T1, the yield was more dependent on fertilization rate （REF = 60.2）. We found TI to be more economic as the optimum N rate varied from N60 to N100 kg hat and the benefit in monetary terms raised from 297ε hal （＂Monsun＂ 2007） to 9056 hal （＂Vinjett＂ 2008）. In T2, N rate 60 kg ha^-1 raised the monetary benefit from 806 ha^-1 （＂Monsun＂ 2007） to 731ε ha^-1 （＂Vinjett＂ 2008）. The highest economic profit was gained by using low rates of fertilizer for ＂Monsun＂ and the highest rates of fertilizer for ＂Vinjett＂.
文摘Background Silicon gel is unfavourable for cell attachment and growth. This study was to study if pretreating the surface of silicon gel with chemical agents affects the proliferation of epithelial cells Methods Silicon gel was made and treated with either mixed acid solution (containing 232 g/dm 3 of H 2SO 4 and 8 g/dm 3 of K 2Cr 2O 7) or 300 cm 3/dm 3 peroxide for 5, 10, and 15 minutes or 10, 15, and 20 minutes, respectively The cultured corneal epithelial cells were seeded onto those silicon gels and kept for 13 days Immunohistochemical investigations were then carried out for integrin (alpha 6 or beta 4) and actin KH*2/5DResults Growth of the epithelial cells in silicon gels treated with mixed acid solution for 10 minutes and 15 minutes was much significant than that in the untreated gels After a 12-hour culture, a small number of corneal epithelial cells were proliferated on the surface of the silicon gels that had been treated with peroxide for 15 minutes After a 3-day culture, those cells were further proliferated and fused together The corneal epithelial cells did not grow well in the silicon gels treated with peroxide for 10 or 20 minutes Immunostaining revealed the expression of actin and integrin alpha 6 or beta 4 on the silicon gels that were treated with mixed acid solution for 10 minutes or peroxide for 15 minutes Conclusion Silicon gels treated either with mixed acid solution for 10 or 15 minutes or with peroxide for 15 minutes improves cell proliferation
基金The work was supported by the National Natural Science Foundation of China(No.69776026)the Foundation for University Key Teacher by the Ministry of Education.
文摘With the progress of ULSI technology, materials with low dielectric constant are required to replace SiO2 film as the interlayer to scale down the interconnection delay. Fluorinated Si oxide thin films (SiOF) are a promising material for the low dielectric constant and the process compatibility in existing technology. However, SiOF films are liable to absorb moisture when exposed to air. By treating the SiOF films with O-2 plasma, it was found that the moisture resistibility of SiOF films was remarkably improved. The mechanism of the improvement in stability of dielectric constant was investigated. The results show that: 1) F atoms dissociated from the films and the bond angle of Si-O-Si decreased. 2) The plasma treatment enhanced the strength of Si-F bonds by removing unstable =SiF2 structures in the films. Resistibility of SiOF films in moisture was improved.
基金the Czech Science Foundation(Project No.104/08/02290)the Czech Ministry of Industry and Trade(Project CZ.1.03/5.1.00/12.00010)the Czech Ministry of Education(Project MSM0021622411)
文摘This paper is aimed to show the influence of initial chemical pretreatment prior to subsequent plasma activation of aluminum surfaces.The results of our study showed that the state of the topmost surface layer（i.e.the surface morphology and chemical groups）of plasma modified aluminum significantly depends on the chemical precleaning.Commonly used chemicals（isopropanol,trichlorethane,solution of Na OH in deionized water）were used as precleaning agents.The plasma treatments were done using a radio frequency driven atmospheric pressure plasma pencil developed at Masaryk University,which operates in Ar,Ar/O_2 gas mixtures.The effectiveness of the plasma treatment was estimated by the wettability measurements,showing high wettability improvement already after 0.3 s treatment.The effects of surface cleaning（hydrocarbon removal）,surface oxidation and activation（generation of OH groups）were estimated using infrared spectroscopy.The changes in the surface morphology were measured using scanning electron microscopy.Optical emission spectroscopy measurements in the near-to-surface region with temperature calculations showed that plasma itself depends on the sample precleaning procedure.
基金Supported by National Natural Science Foundation of China(No.31601997)~~
文摘Birdsfoot trefoil （Lotus corniculatus L.） is high in nutritional value and adapted to slightly acidic, droughty, infertile, or wet soils. However, the impermeable seed coat restricts water imbibition and results in poor seed germination and subse- quent stand establishment. The aim of this study was to identify the dormancy mechanism of Birdsfoot trefoil seeds, and investigate the suitable pretreatment to overcome the poor seed germination. Germination behavior was characterized by using the final germination percentage and the mean germination time. The results indicated that coat thickness of dormant seeds was significant larger. The average hard seed rate was up to 92.3%. It was found that mechanical scarification, chemi- cal scarification with concentrated sulfuric acid （98% H_2SO_4）, and gibberellic acid soaking following freezing below zero temperature were effective in reducing hard- seededness and lead to increases of seed germination.
文摘Experiments were carried out to study the removal of heavy metals from municipal sewage sludge by proper method for land application. The sequential extractions for metal fractionation showed that the non digested sludge from Guangzhou contained Cu and Zn principally bound to carbonate and oxides and the metal sulfides were low. Among H 2SO 4, EDTA and NH 4HCO 3 extractant agents, H 2SO 4 was the most efficient and economic in removing the heavy metals, especially with the addition of the concentrated acid. Plant experiment in pots with Chinese cabbage ( Brassica Chinensis ) showed that the acidified sludges neutralized with alkaline amendments such as phosphate rock could increase significantly the plant yield and decreased the soil and plant contamination by heavy metals originated from sewage sludge.
基金the National Natural Science Foundation of China (Grant No.30070606) and Graduate Cultivation Foundation of Beijing Forestry University(Grant No.304)
文摘In order to clarify the relationship between the microstructural changes and the rheological behaviors of four chemically treated woods (delignified wood, hemicellulose-removed wood, DMSO swollen and decrystallization treated wood), the stress relaxation of wood with three different moisture contents was determined during periodic temperature changes. The experi- mental results show that after wood relaxation for 4 h at 25 °C, the stress decays sharply when the temperature increases and 2 h later the stress recovers again when the temperature drops back to the original point. The additional stress relaxation, produced after tem- perature begins to increase, is mainly caused by the thermal swelling, molecular thermal movement and the break of a part of residual hydrogen bonds. The number of hydrogen bonds and the size and amount of cavities in various treated woods greatly affect the magnitude of the additional relaxed stress and the recovery stress.
基金Supported by the National Natural Science Foundation of China (Grant No. 30070606)Graduate Cultivation Foundation of Beijing Forestry University(Grant No. 304)
文摘In order to clarify the effect of drying on structural changes of DMSO swell treated and DEA-SO2-DMSO decrystallization treated Chinese fir （Cunninghamia lanceolate） wood, the stress relaxation of treated oven-dry specimens during the processes of temperature elevation and reduction and that of treated wet specimens at constant temperature were determined. A stress decrease process and a stress increase process were observed in all stress ratio curves of wood during the processes of decreasing temperature. Untreated wood, during the process of temperature reduction under higher initial temperature conditions and during the process of temperature elevation, has a larger stress decrease than treated woods. In a wet state this trend is reversed. It indicated that the drying set made treated woods have a smaller increase in fluidity of wood constituents with increasing temperature. Some bonding between decrystallization reagents and wood molecules may occur.
基金This research was supported by the Austrian Research Promotion Agency(FFG).
文摘The objective of this work is to carry out the chemical treatment for the hemp fabrics in a closed vacuum system and to prepare bio-based composites using treated hemp fabrics.The change in surface tension of the treated fabrics was measured using contact angle measurement and the wetting behavior using a tensiometer.Bio-based composites were fabricated using bio-based epoxy resin and different chemically treated fabrics.The flexural strength and dynamic water absorption behavior of the composites were characterized.The acetylated fabrics showed very good wetting behavior,and the contact angle values were marginally low compared to other treatment techniques.The bio-based composites fabricated using maleic anhydride treated fabrics achieved the flexural strength of 148 MPa and the dynamic water absorption values were less than 6%.The acetylated and maleic anhydride treatment methods were effective chemical treatments for the hemp fabrics and they enhanced both the wettability and fiber-matrix interaction.The chemical treatment methods that are carried out in the sealed environment can be utilized for all other natural fabrics that help overcome the moisture absorption behavior.
文摘Each year, ethanol production is increasing in Brazil, consequently, the generation of byproducts as well. Among these, the vinasse stands out. With polluting power a hundred times greater than domestic sewage and high concentration of minerals, vinasse is generated in large volumes. Because of these characteristics, it is widely used in fertirrigation. However, it is composed of about 97% water, inflating the cost of the transport from the plant to the field. For these reasons, removing water from the vinasse and the consequent concentration of solids is an alternative management and application of this by-product. This project aimed to analyze the efficiency of various physical and chemical processes in the removal of water from the vinasse.
基金Project supported by the Hi-Tech Research and Development Program (863) of China (No. 2002AA601320) the Shandong Environment Protection Bureau Program (No. 2006032, 2006043)the Ph.D Fund of Shandong Jianzhu University (No. 624006, 2006043).
文摘The particle characterization from the influent and effluent of a chemical-biological flocculation （CBF） process was studied with a laser diffraction device. Water samples from a chemically enhanced primary treatment （CEPT） process and a primary sediment tank process were also analyzed for comparison. The results showed that CBF process was not only effective for both the big size particles and small size particles removal, but also the best particle removal process in the three processes. The results also indicated that CBF process was superior to CEPT process in the heavy metals removal. The high and non-selective removal for heavy metals might be closely related to its strong ability to eliminate small particles. Samples from different locations in CBF reactors showed that small particles were easier to aggregate into big ones and those disrupted flocs could properly flocculate again along CBF reactor because of the biological flocculation.
基金Funded by the Key Project of Science and Technology of Ministry of Education of China(No.108129)
文摘The influences of chromium-free chemical conversion treatment and anodizing treatment on bonding strength of AZ31 magnesium alloy were studied by lap-shear test, SEM and electrochemical methods. Both chemical conversion treatment and anodizing can increase the bonding strength. The anodizing treatment gives higher bonding strength and better corrosion resistance than chemical conversion treatment. The increase of bonding strength by the treatmetlts may be attributed to the uneven surface structures with micro-pores, resulting in increased bonding areas and the embedding effect.
文摘This paper studies a compound treatment. i. e. liquid S , N,C co-diffusing with rare earth (RE) and then oxidization , for hot-working die steels , and the effect of RE on thermal fatigue behavior of the diffused layer. XRD and SEM energy spectrum prove that trace RE element actually penetrates into the surface layer of steels. The result shows that RE can reduce the gradient of change of hardness in diffused layer, improve the morphology and distribution of compounds , and reduce the degree of surface alligator crack for thermal fatigue. The behavior of thermal fatigue of hot-working die steels is raised by 70% or so after the application of RE. The effect of RE is analysed according to the theory.
文摘The accumulation of generated chemical wastes posed a serious problem for the UP College of Pharmacy. The faculty from the Department of Pharmaceutical Chemistry devised a scheme for the identification and segregation of the chemical wastes and created a system for proper disposal of future chemical wastes. There were a total of 1,142 of accumulated chemical waste bottles, 804 of which were subjected to identification and segregation procedures. The wastes were preliminarily tested for its solubility/miscibility in water and acidity or basicity. The identification was done by qualitative tests for cyanide, sulfide, halogenated, non-halogenated, oxidizing, nitro, and heavy metal compounds. The final segregation was based on the presence of the most hazardous component or on pH and water-miscibility. The Department then developed and implemented a scheme for the proper disposal of the chemical wastes generated in laboratory experiments done in the College. Laboratory experiments were also modified to use less toxic and less amounts of chemicals.
