In order to research the bond properties between corroded reinforcement bars and concrete,reinforcement bars with different diameters and different types and concrete with different strength levels were treated specia...In order to research the bond properties between corroded reinforcement bars and concrete,reinforcement bars with different diameters and different types and concrete with different strength levels were treated specially with all soaking and impressed current method,and the bond properties were measured with the pull-out test.The comparative analysis of the bond properties of corroded reinforcement bars was carried out.The results showed that the types of reinforcement bars and concrete had great influence on the bond strength.The corrosion and volume expansion of reinforcement bars made concrete in tensile condition,which tended to produce cracks in parallel reinforced direction.The typical bond failure of plain reinforcement bars was pull-out,while the typical bond failure of ribbed reinforcement bars was split.The bond strength between corroded reinforcement bars and concrete increased with the increase of concrete strength.The bond strength of plain and ribbed reinforcement bars showed a decreasing trend after the first increase with the increase of the extent of corrosion.Through the test,the coefficients of the bond strength of plain and ribbed reinforcement bars were given,respectively.展开更多
[Objective] This study aimed to investigate the effects of salt stress on seed germination and seedling growth in radish（Raphanus sativus L.）.[Method] First,effects of soaking seeds with clear water and different co...[Objective] This study aimed to investigate the effects of salt stress on seed germination and seedling growth in radish（Raphanus sativus L.）.[Method] First,effects of soaking seeds with clear water and different concentrations of saline solution were compared; then,different concentrations of salt solution （0.2％-1.0％） was used to treat radish during the whole germination period.[Result] soaking seeds with clear water can improve the germination indicators of radish seeds exposed to high salt stress; low salt concentration（0.2％,0.4％） had little effect on the growth indicators of radish seedlings,and 0.2％ salt concentration can even promote the growth of radish seedlings,however,the high salinity had a bad inhibition on seedling growth,the higher the salt concentration,the stronger the inhibition.[Conclusion] According to the comprehensive comparison,the order of the six varieties in salt-tolerance was as follows：Xinxiayuanbai＞W1029,Xiayuanbai ＞ Nanyangbailizhi,Chunyidianhong＞ Sijihong 3.展开更多
The inhibitory effect of phosphate on the crystal grain growth of nanosized titania during high temperature calcination was investigated. Nanosized titanium dioxide powders prepared by hydrolysis of titanium tetrachlo...The inhibitory effect of phosphate on the crystal grain growth of nanosized titania during high temperature calcination was investigated. Nanosized titanium dioxide powders prepared by hydrolysis of titanium tetrachloride were soaked in phosphate solutions with different concentrations. The obtained powders calcined at various temperatures were characterized by X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FTIR）, and X-ray photoelectronic spectroscopy （XPS）. The grain size of the samples without phosphate treatment increased quickly when calcined at high temperatures, while the grain size of the samples with phosphate modification increased slowly when calcined at the same temperature. This phenomenon implies that phosphate treatment plays an important role in inhibiting the crystal grain growth of titania. The possible mechanism of the inhibition effect of phosphate on titania is discussed.展开更多
Vegetative propagation by stem cutting is an important technique applied for agricultural production where rooting success is one of the major aspects. A study to assess the effects of mode of application of rooting h...Vegetative propagation by stem cutting is an important technique applied for agricultural production where rooting success is one of the major aspects. A study to assess the effects of mode of application of rooting hormones (IBA) on adventitious root formation of V. paradoxa stem cuttings was conducted. Accordingly, four application methods were investigated in a 4 × 3 factorial experiment using a Completely Randomized Design (CRD). The application methods were: 24-hour extended soak, foliar spraying, basal quick dip and delayed IBA application method. Thus, the parameters used to determine rooting success were mean root length and root number. The effect of these application methods on occurrence of bud break was also considered. On the whole, root length was observed to be a function of IBA concentration, whereby root length increased significantly (P ≤ 0.05) with an increment in IBA concentration. Stem cuttings subjected to 24-h extended soak at 100 ppm rooted best (59.5% ± 8.33%), where as foliar sprayed stem cuttings exhibited the worst rooting success (11.9 ± 3.06 - 23.8% ± 4.16%). Bud break appeared to decrease with increasing IBA concentration and delaying IBA application enhanced rooting percentage of the quick dip method by 7.1%, 9.5% and 11.9% at 2500 ppm, 3500 ppm and 4500 ppm, respectively. The extended soak method of IBA application at 80 ppm shows potential for large scale production of V. paradoxa through stem cuttings.展开更多
基金Supported by National Science and Technology Support Program(No.2012BAJ16B05)Program for Liaoning Excellent Talents in University(No.LJQ2011061)
文摘In order to research the bond properties between corroded reinforcement bars and concrete,reinforcement bars with different diameters and different types and concrete with different strength levels were treated specially with all soaking and impressed current method,and the bond properties were measured with the pull-out test.The comparative analysis of the bond properties of corroded reinforcement bars was carried out.The results showed that the types of reinforcement bars and concrete had great influence on the bond strength.The corrosion and volume expansion of reinforcement bars made concrete in tensile condition,which tended to produce cracks in parallel reinforced direction.The typical bond failure of plain reinforcement bars was pull-out,while the typical bond failure of ribbed reinforcement bars was split.The bond strength between corroded reinforcement bars and concrete increased with the increase of concrete strength.The bond strength of plain and ribbed reinforcement bars showed a decreasing trend after the first increase with the increase of the extent of corrosion.Through the test,the coefficients of the bond strength of plain and ribbed reinforcement bars were given,respectively.
文摘[Objective] This study aimed to investigate the effects of salt stress on seed germination and seedling growth in radish（Raphanus sativus L.）.[Method] First,effects of soaking seeds with clear water and different concentrations of saline solution were compared; then,different concentrations of salt solution （0.2％-1.0％） was used to treat radish during the whole germination period.[Result] soaking seeds with clear water can improve the germination indicators of radish seeds exposed to high salt stress; low salt concentration（0.2％,0.4％） had little effect on the growth indicators of radish seedlings,and 0.2％ salt concentration can even promote the growth of radish seedlings,however,the high salinity had a bad inhibition on seedling growth,the higher the salt concentration,the stronger the inhibition.[Conclusion] According to the comprehensive comparison,the order of the six varieties in salt-tolerance was as follows：Xinxiayuanbai＞W1029,Xiayuanbai ＞ Nanyangbailizhi,Chunyidianhong＞ Sijihong 3.
基金Support of the National Natural Science Foundation of China (No. 20671028)the Natural Science Foundation of Hebei Province (No. E2006000172)the Postdoctoral Science Foundation of China (No. 2005038511)
文摘The inhibitory effect of phosphate on the crystal grain growth of nanosized titania during high temperature calcination was investigated. Nanosized titanium dioxide powders prepared by hydrolysis of titanium tetrachloride were soaked in phosphate solutions with different concentrations. The obtained powders calcined at various temperatures were characterized by X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FTIR）, and X-ray photoelectronic spectroscopy （XPS）. The grain size of the samples without phosphate treatment increased quickly when calcined at high temperatures, while the grain size of the samples with phosphate modification increased slowly when calcined at the same temperature. This phenomenon implies that phosphate treatment plays an important role in inhibiting the crystal grain growth of titania. The possible mechanism of the inhibition effect of phosphate on titania is discussed.
文摘Vegetative propagation by stem cutting is an important technique applied for agricultural production where rooting success is one of the major aspects. A study to assess the effects of mode of application of rooting hormones (IBA) on adventitious root formation of V. paradoxa stem cuttings was conducted. Accordingly, four application methods were investigated in a 4 × 3 factorial experiment using a Completely Randomized Design (CRD). The application methods were: 24-hour extended soak, foliar spraying, basal quick dip and delayed IBA application method. Thus, the parameters used to determine rooting success were mean root length and root number. The effect of these application methods on occurrence of bud break was also considered. On the whole, root length was observed to be a function of IBA concentration, whereby root length increased significantly (P ≤ 0.05) with an increment in IBA concentration. Stem cuttings subjected to 24-h extended soak at 100 ppm rooted best (59.5% ± 8.33%), where as foliar sprayed stem cuttings exhibited the worst rooting success (11.9 ± 3.06 - 23.8% ± 4.16%). Bud break appeared to decrease with increasing IBA concentration and delaying IBA application enhanced rooting percentage of the quick dip method by 7.1%, 9.5% and 11.9% at 2500 ppm, 3500 ppm and 4500 ppm, respectively. The extended soak method of IBA application at 80 ppm shows potential for large scale production of V. paradoxa through stem cuttings.
