This paper reported the diurnal variations of photochemical efficiency of PSII, thermaldissipation rate and other physiology process in the low content chlorophyll mutant rice andits wild type under field conditions, ...This paper reported the diurnal variations of photochemical efficiency of PSII, thermaldissipation rate and other physiology process in the low content chlorophyll mutant rice andits wild type under field conditions, and analyzed the difference of absorbed light distributionbetween the two rice varieties in a day. The results showed that the mutant had poor absorbedlight because of its little light absorption coefficient, but higher electron transportg ratecould partly reduce the disadvantageous effect of deficient absorbed light in mutant. Comparedwith wild-type rice, the mutant had less excess excitation energy and the fraction of absorbedlight allocated to photochemical process was more.展开更多
In this study,newly developed low content PCBN was used to evaluate the cutting performance in high speed turning of hardened steel.Using new PCBN and commercially available PCBN tipped inserts under the same cutting ...In this study,newly developed low content PCBN was used to evaluate the cutting performance in high speed turning of hardened steel.Using new PCBN and commercially available PCBN tipped inserts under the same cutting condition,cutting performance with variable cutting speed,feed rate and depth of cuts on tools were measured by observation of flank and crater wear.Its microstructures were analyzed through SEM microscope,measurement of surface roughness on workpiece was also performed. According to cutting performance results,it is shown that new PCBN shows much longer tool life in high speed continuous turning than our conventional PCBN tools,with improved wear and chipping resistance.This result on the machinability of new PCBN for hardened steel will provide effective guidelines to manufacturing engineers,also provide useful economic machining solution for high speed continuous turning for hardened steel.展开更多
Low cobalt(Co)WC hard materials were prepared using vacuum sintering.The influences of Co content on the sintering densification behavior,grain growth characteristics,microstructure and mechanical properties of WC har...Low cobalt(Co)WC hard materials were prepared using vacuum sintering.The influences of Co content on the sintering densification behavior,grain growth characteristics,microstructure and mechanical properties of WC hard material were studied.The experimental results show that the addition of a small amount of Co significantly promotes the densification and reduces the sintering temperature.Meantime,the abnormal growth of WC grains was observed.When the sintering temperature is 1300℃and the content of Co is less than 1.0wt%,densed WC/Co hard material with fine grains is obtained.When the content of Co is 1wt%,the relative density,Vickers hardness,and flexural strength of WC material are 98.76±0.17%,24.23±0.41 GPa,and 1376±67 MPa,respectively.When the Co content is 0.25wt%and 0.5wt%,the optimal sintering temperature of the sample is 1350℃.Among them,the relative density,hardness,and flexural strength of WC-0.5wt%Co are 98.79±0.15%,23.44±0.38 GPa,and 1233±85 MPa,respectively.展开更多
To improve the processability and mechanical properties of the selective laser melting(SLM)low Sc content Al−Mg−Sc−Zr alloy,Mn was used to partially replace Mg.The processability,microstructure,and mechanical properti...To improve the processability and mechanical properties of the selective laser melting(SLM)low Sc content Al−Mg−Sc−Zr alloy,Mn was used to partially replace Mg.The processability,microstructure,and mechanical properties of the SLM-fabricated Al−Mg−Mn−Sc−Zr alloy were systematically investigated by density measurement,microstructure characterization,and tensile testing.The results revealed that dense samples could be obtained by adjusting the SLM process parameters.The alloy exhibited a fine equiaxed-columnar bimodal grain microstructure.The presence of primary Al3Sc andα-Al(Mn,Fe)Si particles contributed to the grain refinement of the alloy with an average grain size of 4.63μm.Upon aging treatment at 350°C for 2 h,the strength and elongation of the alloy were simultaneously improved due to the precipitation of Al3Sc nanoparticles and the formation of the 9R phase.This study demonstrates that the strength−plasticity trade-off of the aluminum alloy can be overcome by utilizing SLM technology and subsequent post-heat treatment to induce the formation of the long-period stacked ordered phase.展开更多
Fe_(2)O_(3)/Al_(2)O_(3) and Fe_(2)O_(3)/Al_(2)O_(3) modified by low content of Ni(below 2%in weight)oxygen carriers were prepared by mechanical mixing and impregnation method.The synthesized oxygen carriers were chara...Fe_(2)O_(3)/Al_(2)O_(3) and Fe_(2)O_(3)/Al_(2)O_(3) modified by low content of Ni(below 2%in weight)oxygen carriers were prepared by mechanical mixing and impregnation method.The synthesized oxygen carriers were characterized by means of X-ray diffraction(XRD),X-ray fluorescence(XRF),scanning electron microscopy(SEM),BET-surface area and temperature programmed reduction(TPR).Besides,redox cyclic reactivity and the performance of chemical looping reforming of methane of the oxygen carriers were studied in a thermal gravimetrical analysis(TGA)and fixed bed at 850℃.It was observed that the redox reactivity of the oxygen carriers is improved by Ni addition because synergic effect may occur between NiO and Fe_(2)O_(3)/Al_(2)O_(3) to form NiFe_(2)O_(4) and NiAl_(2)O_(4) spinel phases.However,the improvement was not apparent as Ni addition reached 1 wt%or more because more nickel loaded resulted in methane decomposition into H2 and carbon leading to carbon deposition.The SEM and BET analysis showed that NiFe_(2)O_(4) and NiAl_(2)O_(4) particles dispersed into the pores of the Fe_(2)O_(3)/Al_(2)O_(3) particles in the course of preparation.In addition,the resistance to sintering of the modified samples increased with the Ni addition increasing.The results of successive redox cycles showed that the Ni modified Fe_(2)O_(3)/Al_(2)O_(3) oxygen carriers have good regenerability.With integration of reactivity and carbon deposition,the content 1.04 wt%of nickel doping was an optimal amount in the three modified samples.展开更多
Rice with low glutelin content is suitable as functional food for patients affected with diabetes and kidney failure. The fine mapping of the gene(s) responsible for low glutelin content will provide information regar...Rice with low glutelin content is suitable as functional food for patients affected with diabetes and kidney failure. The fine mapping of the gene(s) responsible for low glutelin content will provide information regarding the distribution of glutelin related genes in rice genome and will generate markers for the selection of low glutelin rice varieties. Following an SDS-PAGE screen of rice germplasm from Taihu Valley of China, Japonica selection W3660 is identified to be a novel mutant characterized with low glutelin content. For fine mapping the mutant gene for low glutelin content, F2 and F3 populations were derived from a cross between W3660 and Jingrennuo. SDS-PAGE analysis of the total endosperm protein showed that the low glutelin content trait was controlled by a single dominant nuclear gene. Genetic mapping, using SSRs, located this gene to chromosome 2, in the region between SSR2-001/SSR2-004 and RM1358. The dis- tances of the two markers to the target gene were 1.1 cM and 3.8 cM respectively. By semi-quantitative RT-PCR analysis, the transcripts of GluB4/GluB5 genes located within the region do not change. However, GluB5 gene located proximal to SSR2-001/SSR2-004 was specifically reduced. SSR profiles of seven Japonica varieties were compared with that of W3660 for loci in the relevant genetic region. The markers SSR2-004 and RM1358 were used for marker- assisted selection. The selection efficiencies of SSR2-004 and RM1358 were 96.8% and 92.7% respectively. This provides a standard starting point for the breeding of low glutelin content rice varieties in China.展开更多
Amylose content is a key determinant of eating quality of rice. With the characteristics offluffy texture, glossy appearance when cooked, remaining soft when cooled and excellentpuffing ability, the low-amylose rice w...Amylose content is a key determinant of eating quality of rice. With the characteristics offluffy texture, glossy appearance when cooked, remaining soft when cooled and excellentpuffing ability, the low-amylose rice with amylose content 5-15% could be served as not onlycooked rice directly, but also good material for convenience, mixed rice and puffing foods.Current status on characterization, inheritance, molecular mechanism and breeding of low-amylose content rice was reviewed in this paper, strategy of related researches in the era ofglymics was mainly discussed furthermore. The future research should focus on screening andenhancing the germplasm, further elucidating the molecular mechanism on mutation of lowamylose content, utilizing the genes independent of Wx on low-amylose content rice breedingprogram, and developing high quality functional rice cultivars for special usage throughpyramiding low amylose gene and other special quality genes.展开更多
A series of Al based alloys with low titanium contents (mass fraction) from 0.178% to 0.526% were directly produced in ordinary industrial electrolyzer. The electrolyzing results show that producing Al based alloys wi...A series of Al based alloys with low titanium contents (mass fraction) from 0.178% to 0.526% were directly produced in ordinary industrial electrolyzer. The electrolyzing results show that producing Al based alloys with titanium contents of less than 0.30% without great loss of electrolysis efficiency is possible. The quantitative analysis shows that this method has a great refining effect on transiting the coarse columnar grains in pure Al to equiaxed grains. The grain sizes decrease with the increase of titanium content and tend to a low limit at about 130 μm. During the solidification, the non equilibrium distribution of titanium leads to a great growth restricting effect and a constitutional under cooling zone in front of the growing liquid /solid interface.展开更多
In this work,several ceria-zirconia based catalysts with very lo w(and equimolar) metal contents were prepared,characterised and tested for the CO oxidatio n reaction(under lean and stoichiometric conditions),trying t...In this work,several ceria-zirconia based catalysts with very lo w(and equimolar) metal contents were prepared,characterised and tested for the CO oxidatio n reaction(under lean and stoichiometric conditions),trying to emulate those conditions found in a diesel oxidation catalyst(DOC) system from a diesel engine and those encountered under gasoline exhaust(λ=1).The metals chosen are Cu,Co,Ag and Pt(as a reliable benchmark).The results reveal enormous differences among reducibility and catalytic activity despite quite similar structural and textural properties of the catalysts,showing differences among dispersion(Ag-catalyst seems to present a low level of dispersion).This catalyst seems to be characterised,as well,by a strong electronic interaction between Ce and Ag centres which is suggested to yield an improved reducibility under H_(2)-TPR conditions.Nevertheless,the order in catalytic activity(Cu>Ag>Co≈Pt>>support) seems not to follow the order found in reducibility and the Cu-catalyst seems to be the most active independently on the reaction conditions,yielding nearly overlapped CO oxidation catalytic curves.Inte restingly,a stro ng correlation between the catalytic activity under the two conditions tested and the OSC values of the Ce_(0.8)Zr_(0.2)O_(2)-supported metal catalysts is found.Therefore,OSC parameter measured at 150℃ can be used as a relevant descriptor to evaluate the CO oxidation activity at low and medium conversions for the investigated catalysts,much better than the H_(2)-TPR measurements.展开更多
The oxidation of oxygen ions and the generation of an anode effect at a low oxygen content of 150 mg/kg were discussed in this paper.Cyclic voltammetry and square-wave voltammetry tests were conducted to explore the a...The oxidation of oxygen ions and the generation of an anode effect at a low oxygen content of 150 mg/kg were discussed in this paper.Cyclic voltammetry and square-wave voltammetry tests were conducted to explore the anodic processes of LiF-NdF_(3)melt after a lengthy period of pre-electrolysis purification at 1000℃(during which the oxygen content reduced from 413 to 150 mg/kg).The oxidation process of oxygen ions was found to have two stages:oxidation product adsorption and CO/CO_(2)gas evolution.The adsorption stage was controlled by diffusion,whereas the gas evolution was controlled by the electrochemical reaction.In comparison with oxygen content of 413 mg/kg,the decrease in the amplitude of the current at low oxygen content of 150 mg/kg was much gentler during the forward scanning process when the anode effect occurred.Fluorine-ion oxidation peaks that occurred at about 4.2 V vs.Li/Li+could be clearly observed in the reverse scanning processes,in which fluorine ions were oxidized and perfluorocarbons were produced,which resulted in an anode effect.展开更多
Rice with low glutelin content is suitable as functional food for patients affected by kidney failure. Low glutelincontent gene Lgc1 in rice has a 3.5-kb deletion between two highly similar glutelin genes GluB4 and Gl...Rice with low glutelin content is suitable as functional food for patients affected by kidney failure. Low glutelincontent gene Lgc1 in rice has a 3.5-kb deletion between two highly similar glutelin genes GluB4 and GluB5, which locates on the short arm of chromosome 2. To improve the selection efficiency in low glutelin-content rice breeding, two molecular markers designated as InDel-Lgc1-1 and InDel-Lgc1-2 were developed to detect the low glutelin-content gene Lgc1. A double PCR detection indicated that combined use of the two markers could easily distinguish the genotypes of Lgc1 from different rice varieties. Therefore, as a simple and low-cost technique, the molecular marker could be widely used to identify different varieties with Lgc1 gene and applied in marker-assisted selection of low glutelin-content rice.展开更多
Continuous cooling transformation behaviors of low carbon steels with two Si contents （0. 50% and 1. 35%） were investigated under undeformed and deformed conditions. Effects of Si contents, deformation, and cooling ...Continuous cooling transformation behaviors of low carbon steels with two Si contents （0. 50% and 1. 35%） were investigated under undeformed and deformed conditions. Effects of Si contents, deformation, and cooling rates on γ transformation start temperature （Ar3）, phase microstructures, and hardness were studied. The results show that, in the ease of the deformation with the true strain of 0. 4, the length of bainitic ferrite laths is significantly decreased in low Si steel, whereas, the M/A constituent becomes more uniform in high Si steel. An increase in cooling rates lowers the Ar3 greatly. The steel with higher level of Si exhibits higher Ar3, and higher hardness both under undeformed and deformed conditions compared with the steel with a lower Si content. Especially, the influence of Si on At3 is dependent on deformation. Such effects are more significant under the undeformed condition. The hardness of both steels increases with the increase of cooling rates, whereas, the deformation involved in both steels reduces the hardness.展开更多
There are some problems in steelmaking with hot metal containing low silicon content such as difficulty in slag formation, less slag for dephosphorization and slag adhesion on oxygen lance and hood. To overcome these ...There are some problems in steelmaking with hot metal containing low silicon content such as difficulty in slag formation, less slag for dephosphorization and slag adhesion on oxygen lance and hood. To overcome these problems, experiments wcrc conducted and some improvements were obtained, such as adding appropriate flux, increasing the lance position slightly during steelmaking and using effective multi-outlet nozzle. Moreover, to keep normal heating rate, the ore and scrap charge should be reduced due to less chemical heat input in steelmaking.展开更多
Fine unsaturated soils are used in many applications, particularly in road infrastructure and in construction. These materials undergo deformations according to the stresses to which they are subjected. The purpose of...Fine unsaturated soils are used in many applications, particularly in road infrastructure and in construction. These materials undergo deformations according to the stresses to which they are subjected. The purpose of this paper is to study the influence of hydromechanical stresses on the behavior of low swelling soils compacted at low water content in accordance with the French standard GTR 92 (Guide des Terrassements Routiers). Then, various experimental tests on an oedometer were carried out in the laboratory. Two types of low swelling soil sampled in Nasso on the outskirts of the town of Bobo Dioulasso (Burkina Faso) were used. After shuffling, each sample was moistened to its optimum water content and then compacted to 90% and 95% of its optimum density. Behavior tests show that these soils deform very little when subjected to hydromechanical stresses. However, these deformations are swelling in nature for low mechanical stresses and when the stresses are high, they tend to collapse. When these soils are subjected to a vertical stress of 420 kPa, the primary consolidation time is of the order of one minute for NH<sub>2</sub> (a silty soil) and about ten minutes for NH<sub>3 </sub>(a silty-clayed soil).展开更多
Here, we introduce a new type of molecular imprinted polymer (MIP) with immobilized assistant recognition polymer chains (ARPCs) to create effective recognition sites and with bacterial cloned protein as template for ...Here, we introduce a new type of molecular imprinted polymer (MIP) with immobilized assistant recognition polymer chains (ARPCs) to create effective recognition sites and with bacterial cloned protein as template for adsorbing the low content target protein from cell extract. In this work, cloned pig cyclophilin 18 (pCyP18), a peptidyl-prolyl cis/trans-isomerase, was used as template. The template protein was selectively assembled with ARPCs from their library, which consists of numerous limited length polymer chains with randomly distributed recognition sites of positively charged amino groups and immobilizing sites. These assemblies were adsorbed by porous microsphers and immobilized on them. After removing the template, binding sites complementary to the target protein in size, shape and the position of recognition groups were exposed, and their confirmation was preserved by the cross-linked structure. The synthesized MIP was used to adsorb the cellular pCyP18, and its proportional content was enriched more than hundred times. The extended experiment on imprinting bovine serum albumin (BSA) with ARPCs shows that this method is also suitable for large protein.展开更多
The large and dense rare earth (RE)-oxide inclusions in high-oxygen RE metal increase the risk of producing variable properties in RE steel. Consequently, a self-developed electrolysis cell was utilized for the produc...The large and dense rare earth (RE)-oxide inclusions in high-oxygen RE metal increase the risk of producing variable properties in RE steel. Consequently, a self-developed electrolysis cell was utilized for the production of low-oxygen La/Ce mischmetal. The electrolysis process and the origin of oxygen in mischmetal were comprehensively investigated. The results indicate that the reaction between La/Ce oxide and fluoride molten salt results in the formation of La/Ce oxy-fluoride. The deposition of oxy-fluoride at the bottom of the electrolysis cell is the primary factor contributing to the increased oxygen content in mischmetal. The comprehensive influence of oxide addition quantity, feeding interval, and electrolysis temperature on oxygen content, purity, and current efficiency using the response surface methodology model is revealed. The results for industrial experiment show that the purity of mishcmetal reaches higher than 99.78 wt.%, the oxygen content of mischmetal is only 0.0047 wt.% and the current efficiency of the electrolysis process achieves 80.79% under the optimized parameters of 225 kg/d, 30 s and 1069 ℃. The findings offer valuable insights into the application of molten salt electrolysis for the production of low-oxygen mischmetal.展开更多
A study was conducted to screen out the low-temperature tolerant Boro rice seedlings from November 2012 to January 2013 for facing the upcoming rice production challenge in Northwest Bangladesh. The experimental time ...A study was conducted to screen out the low-temperature tolerant Boro rice seedlings from November 2012 to January 2013 for facing the upcoming rice production challenge in Northwest Bangladesh. The experimental time was characterized by a prevailing low environmental temperature of below 15°C. Five rice cultivars (V1: BR-2;V2: BR-16;V3: Pariza;V4: Minicate;V5: BRRI dhan 50) were selected for the study. The leaf proline, chlorophyll content and total carotenoid content were investigated. The V2 (BR-16) seedling synthesized the higher leaf proline (1.228 g·g-1) at a low temperature than those of other tested cultivars. Again, the highest amount of chlorophyll-a (3.957 g·g-1), chlorophyll-b (2.118 g·g-1), chlorophyll-a/b ratio (3.6754 mg·g-1) and total chlorophyll (5.051 g·g-1) was measured in V2 (BR-16). The maximum total carotenoid (1.213 g·g-1) was also observed in V2. In this experiment, the V2 (BR-16) showed comparatively better potentiality to survive at low temperatures (below 15°C) than other varieties.展开更多
Alcohol-assisted low-temperature methanol synthesis was conducted over Cu/ZnO;catalysts while varying the copper content（X）. Unlike conventional methanol synthesis, ethanol acted as both solvent and reaction interme...Alcohol-assisted low-temperature methanol synthesis was conducted over Cu/ZnO;catalysts while varying the copper content（X）. Unlike conventional methanol synthesis, ethanol acted as both solvent and reaction intermediate in this reaction, creating a different reaction pathway. The formation of crystalline phases and characteristic morphology of the co-precipitated precursors during the co-precipitation step were important factors in obtaining an efficient Cu/ZnO catalyst with a high dispersion of metallic copper,which is one of the main active sites for methanol synthesis. The acidic properties of the Cu/ZnO catalyst were also revealed as important factors, since alcohol esterification is considered the rate-limiting step in alcohol-assisted low-temperature methanol synthesis. As a consequence, bifunctionality of the Cu/ZnO catalyst such as metallic copper and acidic properties was required for this reaction. In this respect, the copper content（X） strongly affected the catalytic activity of the Cu/ZnO;catalysts, and accordingly, the Cu/ZnO;.5 catalyst with a high copper dispersion and sufficient acid sites exhibited the best catalytic performance in this reaction.展开更多
To resolve the difficulty in slag formation during steelmaking with low silicon hot metal and to increase productivity, a new 5-hole lance was developed by increasing oxygen flow from 50 000 m^3/h to 60 000 m^3/h. Syn...To resolve the difficulty in slag formation during steelmaking with low silicon hot metal and to increase productivity, a new 5-hole lance was developed by increasing oxygen flow from 50 000 m^3/h to 60 000 m^3/h. Synthetic slag was added to adjust the slag composition. The problems such as difficulty in dephosphorization and slag adhesion to oxygen lance and hood were settled. Steel production and metal yield were increased and the nozzle life was prolonged through these techniques.展开更多
基金supported by the National Natural Science Foundation of China(30300217).
文摘This paper reported the diurnal variations of photochemical efficiency of PSII, thermaldissipation rate and other physiology process in the low content chlorophyll mutant rice andits wild type under field conditions, and analyzed the difference of absorbed light distributionbetween the two rice varieties in a day. The results showed that the mutant had poor absorbedlight because of its little light absorption coefficient, but higher electron transportg ratecould partly reduce the disadvantageous effect of deficient absorbed light in mutant. Comparedwith wild-type rice, the mutant had less excess excitation energy and the fraction of absorbedlight allocated to photochemical process was more.
基金Suported by Advanced Technolgy center prject(No.10020604)
文摘In this study,newly developed low content PCBN was used to evaluate the cutting performance in high speed turning of hardened steel.Using new PCBN and commercially available PCBN tipped inserts under the same cutting condition,cutting performance with variable cutting speed,feed rate and depth of cuts on tools were measured by observation of flank and crater wear.Its microstructures were analyzed through SEM microscope,measurement of surface roughness on workpiece was also performed. According to cutting performance results,it is shown that new PCBN shows much longer tool life in high speed continuous turning than our conventional PCBN tools,with improved wear and chipping resistance.This result on the machinability of new PCBN for hardened steel will provide effective guidelines to manufacturing engineers,also provide useful economic machining solution for high speed continuous turning for hardened steel.
基金Funded by the National Natural Science Foundation of China(No.52022072)the Key Research and Development Plan of Jiangxi Province(No.2020ZDYFB0017)。
文摘Low cobalt(Co)WC hard materials were prepared using vacuum sintering.The influences of Co content on the sintering densification behavior,grain growth characteristics,microstructure and mechanical properties of WC hard material were studied.The experimental results show that the addition of a small amount of Co significantly promotes the densification and reduces the sintering temperature.Meantime,the abnormal growth of WC grains was observed.When the sintering temperature is 1300℃and the content of Co is less than 1.0wt%,densed WC/Co hard material with fine grains is obtained.When the content of Co is 1wt%,the relative density,Vickers hardness,and flexural strength of WC material are 98.76±0.17%,24.23±0.41 GPa,and 1376±67 MPa,respectively.When the Co content is 0.25wt%and 0.5wt%,the optimal sintering temperature of the sample is 1350℃.Among them,the relative density,hardness,and flexural strength of WC-0.5wt%Co are 98.79±0.15%,23.44±0.38 GPa,and 1233±85 MPa,respectively.
基金supported by the National Natural Science Foundation of China(Nos.51801079,52001140)the National Funds Through FCT of Portugal–Fundacao para a Ciência e a Tecnologia,under a scientific contract of 2021.04115.CEECIND,and the Projects of UIDB/00285/2020,and LA/0112/2020。
文摘To improve the processability and mechanical properties of the selective laser melting(SLM)low Sc content Al−Mg−Sc−Zr alloy,Mn was used to partially replace Mg.The processability,microstructure,and mechanical properties of the SLM-fabricated Al−Mg−Mn−Sc−Zr alloy were systematically investigated by density measurement,microstructure characterization,and tensile testing.The results revealed that dense samples could be obtained by adjusting the SLM process parameters.The alloy exhibited a fine equiaxed-columnar bimodal grain microstructure.The presence of primary Al3Sc andα-Al(Mn,Fe)Si particles contributed to the grain refinement of the alloy with an average grain size of 4.63μm.Upon aging treatment at 350°C for 2 h,the strength and elongation of the alloy were simultaneously improved due to the precipitation of Al3Sc nanoparticles and the formation of the 9R phase.This study demonstrates that the strength−plasticity trade-off of the aluminum alloy can be overcome by utilizing SLM technology and subsequent post-heat treatment to induce the formation of the long-period stacked ordered phase.
基金The financial support of the National Natural Science Foundation of China(No.51076154)is gratefully acknowledgedThis work was also supported by the National Key Technology R&D Program of 12^(th) Five-Year Plan of China(No.2011BAD15B05)the Science&Technology Research Project of Guangdong Province(No.2010B010900047).
文摘Fe_(2)O_(3)/Al_(2)O_(3) and Fe_(2)O_(3)/Al_(2)O_(3) modified by low content of Ni(below 2%in weight)oxygen carriers were prepared by mechanical mixing and impregnation method.The synthesized oxygen carriers were characterized by means of X-ray diffraction(XRD),X-ray fluorescence(XRF),scanning electron microscopy(SEM),BET-surface area and temperature programmed reduction(TPR).Besides,redox cyclic reactivity and the performance of chemical looping reforming of methane of the oxygen carriers were studied in a thermal gravimetrical analysis(TGA)and fixed bed at 850℃.It was observed that the redox reactivity of the oxygen carriers is improved by Ni addition because synergic effect may occur between NiO and Fe_(2)O_(3)/Al_(2)O_(3) to form NiFe_(2)O_(4) and NiAl_(2)O_(4) spinel phases.However,the improvement was not apparent as Ni addition reached 1 wt%or more because more nickel loaded resulted in methane decomposition into H2 and carbon leading to carbon deposition.The SEM and BET analysis showed that NiFe_(2)O_(4) and NiAl_(2)O_(4) particles dispersed into the pores of the Fe_(2)O_(3)/Al_(2)O_(3) particles in the course of preparation.In addition,the resistance to sintering of the modified samples increased with the Ni addition increasing.The results of successive redox cycles showed that the Ni modified Fe_(2)O_(3)/Al_(2)O_(3) oxygen carriers have good regenerability.With integration of reactivity and carbon deposition,the content 1.04 wt%of nickel doping was an optimal amount in the three modified samples.
基金supported by the grants from Hi-Tech Research and Development Program of China("863"Program,No.2003AA222131,2003AA207020)the National Natural Science Foundation of China(No.30170570)Special Program for gene-transfering(No.JY03-B-07,JY03-A-07-02)
文摘Rice with low glutelin content is suitable as functional food for patients affected with diabetes and kidney failure. The fine mapping of the gene(s) responsible for low glutelin content will provide information regarding the distribution of glutelin related genes in rice genome and will generate markers for the selection of low glutelin rice varieties. Following an SDS-PAGE screen of rice germplasm from Taihu Valley of China, Japonica selection W3660 is identified to be a novel mutant characterized with low glutelin content. For fine mapping the mutant gene for low glutelin content, F2 and F3 populations were derived from a cross between W3660 and Jingrennuo. SDS-PAGE analysis of the total endosperm protein showed that the low glutelin content trait was controlled by a single dominant nuclear gene. Genetic mapping, using SSRs, located this gene to chromosome 2, in the region between SSR2-001/SSR2-004 and RM1358. The dis- tances of the two markers to the target gene were 1.1 cM and 3.8 cM respectively. By semi-quantitative RT-PCR analysis, the transcripts of GluB4/GluB5 genes located within the region do not change. However, GluB5 gene located proximal to SSR2-001/SSR2-004 was specifically reduced. SSR profiles of seven Japonica varieties were compared with that of W3660 for loci in the relevant genetic region. The markers SSR2-004 and RM1358 were used for marker- assisted selection. The selection efficiencies of SSR2-004 and RM1358 were 96.8% and 92.7% respectively. This provides a standard starting point for the breeding of low glutelin content rice varieties in China.
基金supported by the National Natural Science Foundation of China(30270811).
文摘Amylose content is a key determinant of eating quality of rice. With the characteristics offluffy texture, glossy appearance when cooked, remaining soft when cooled and excellentpuffing ability, the low-amylose rice with amylose content 5-15% could be served as not onlycooked rice directly, but also good material for convenience, mixed rice and puffing foods.Current status on characterization, inheritance, molecular mechanism and breeding of low-amylose content rice was reviewed in this paper, strategy of related researches in the era ofglymics was mainly discussed furthermore. The future research should focus on screening andenhancing the germplasm, further elucidating the molecular mechanism on mutation of lowamylose content, utilizing the genes independent of Wx on low-amylose content rice breedingprogram, and developing high quality functional rice cultivars for special usage throughpyramiding low amylose gene and other special quality genes.
文摘A series of Al based alloys with low titanium contents (mass fraction) from 0.178% to 0.526% were directly produced in ordinary industrial electrolyzer. The electrolyzing results show that producing Al based alloys with titanium contents of less than 0.30% without great loss of electrolysis efficiency is possible. The quantitative analysis shows that this method has a great refining effect on transiting the coarse columnar grains in pure Al to equiaxed grains. The grain sizes decrease with the increase of titanium content and tend to a low limit at about 130 μm. During the solidification, the non equilibrium distribution of titanium leads to a great growth restricting effect and a constitutional under cooling zone in front of the growing liquid /solid interface.
基金Project supported by the Spanish Ministry of Science and Innovation/Research Spanish Agency (PID2019-105 542RB-100/AEI/10.13039/501100011033)the UE-FEDER funding and Generalitat Valenciana (CIPROM/2021/070)。
文摘In this work,several ceria-zirconia based catalysts with very lo w(and equimolar) metal contents were prepared,characterised and tested for the CO oxidatio n reaction(under lean and stoichiometric conditions),trying to emulate those conditions found in a diesel oxidation catalyst(DOC) system from a diesel engine and those encountered under gasoline exhaust(λ=1).The metals chosen are Cu,Co,Ag and Pt(as a reliable benchmark).The results reveal enormous differences among reducibility and catalytic activity despite quite similar structural and textural properties of the catalysts,showing differences among dispersion(Ag-catalyst seems to present a low level of dispersion).This catalyst seems to be characterised,as well,by a strong electronic interaction between Ce and Ag centres which is suggested to yield an improved reducibility under H_(2)-TPR conditions.Nevertheless,the order in catalytic activity(Cu>Ag>Co≈Pt>>support) seems not to follow the order found in reducibility and the Cu-catalyst seems to be the most active independently on the reaction conditions,yielding nearly overlapped CO oxidation catalytic curves.Inte restingly,a stro ng correlation between the catalytic activity under the two conditions tested and the OSC values of the Ce_(0.8)Zr_(0.2)O_(2)-supported metal catalysts is found.Therefore,OSC parameter measured at 150℃ can be used as a relevant descriptor to evaluate the CO oxidation activity at low and medium conversions for the investigated catalysts,much better than the H_(2)-TPR measurements.
基金the National Natural Science Foundation of China(No.51774145).The“Minjiang Scholar”Program of Department of Education,Fujian Province,China was also acknowledged.
文摘The oxidation of oxygen ions and the generation of an anode effect at a low oxygen content of 150 mg/kg were discussed in this paper.Cyclic voltammetry and square-wave voltammetry tests were conducted to explore the anodic processes of LiF-NdF_(3)melt after a lengthy period of pre-electrolysis purification at 1000℃(during which the oxygen content reduced from 413 to 150 mg/kg).The oxidation process of oxygen ions was found to have two stages:oxidation product adsorption and CO/CO_(2)gas evolution.The adsorption stage was controlled by diffusion,whereas the gas evolution was controlled by the electrochemical reaction.In comparison with oxygen content of 413 mg/kg,the decrease in the amplitude of the current at low oxygen content of 150 mg/kg was much gentler during the forward scanning process when the anode effect occurred.Fluorine-ion oxidation peaks that occurred at about 4.2 V vs.Li/Li+could be clearly observed in the reverse scanning processes,in which fluorine ions were oxidized and perfluorocarbons were produced,which resulted in an anode effect.
基金supported by the National Transgenic Crops Program, China (Grant No. 2008ZX08001-006)the Research Funds for Public Benefit in Ministry of Agriculture, China (Grant No. 200803056)+1 种基金the Key Support Program of Jiangsu Science and Technology, China (Grant No. BE2008354)the Self-directed Innovation Fund of Agricultural Science and Technology in Jiangsu Province, China (Grant No. CX [08]603)
文摘Rice with low glutelin content is suitable as functional food for patients affected by kidney failure. Low glutelincontent gene Lgc1 in rice has a 3.5-kb deletion between two highly similar glutelin genes GluB4 and GluB5, which locates on the short arm of chromosome 2. To improve the selection efficiency in low glutelin-content rice breeding, two molecular markers designated as InDel-Lgc1-1 and InDel-Lgc1-2 were developed to detect the low glutelin-content gene Lgc1. A double PCR detection indicated that combined use of the two markers could easily distinguish the genotypes of Lgc1 from different rice varieties. Therefore, as a simple and low-cost technique, the molecular marker could be widely used to identify different varieties with Lgc1 gene and applied in marker-assisted selection of low glutelin-content rice.
基金Item Sponsored by National Natural Science Foundation of China (50527402)
文摘Continuous cooling transformation behaviors of low carbon steels with two Si contents （0. 50% and 1. 35%） were investigated under undeformed and deformed conditions. Effects of Si contents, deformation, and cooling rates on γ transformation start temperature （Ar3）, phase microstructures, and hardness were studied. The results show that, in the ease of the deformation with the true strain of 0. 4, the length of bainitic ferrite laths is significantly decreased in low Si steel, whereas, the M/A constituent becomes more uniform in high Si steel. An increase in cooling rates lowers the Ar3 greatly. The steel with higher level of Si exhibits higher Ar3, and higher hardness both under undeformed and deformed conditions compared with the steel with a lower Si content. Especially, the influence of Si on At3 is dependent on deformation. Such effects are more significant under the undeformed condition. The hardness of both steels increases with the increase of cooling rates, whereas, the deformation involved in both steels reduces the hardness.
文摘There are some problems in steelmaking with hot metal containing low silicon content such as difficulty in slag formation, less slag for dephosphorization and slag adhesion on oxygen lance and hood. To overcome these problems, experiments wcrc conducted and some improvements were obtained, such as adding appropriate flux, increasing the lance position slightly during steelmaking and using effective multi-outlet nozzle. Moreover, to keep normal heating rate, the ore and scrap charge should be reduced due to less chemical heat input in steelmaking.
文摘Fine unsaturated soils are used in many applications, particularly in road infrastructure and in construction. These materials undergo deformations according to the stresses to which they are subjected. The purpose of this paper is to study the influence of hydromechanical stresses on the behavior of low swelling soils compacted at low water content in accordance with the French standard GTR 92 (Guide des Terrassements Routiers). Then, various experimental tests on an oedometer were carried out in the laboratory. Two types of low swelling soil sampled in Nasso on the outskirts of the town of Bobo Dioulasso (Burkina Faso) were used. After shuffling, each sample was moistened to its optimum water content and then compacted to 90% and 95% of its optimum density. Behavior tests show that these soils deform very little when subjected to hydromechanical stresses. However, these deformations are swelling in nature for low mechanical stresses and when the stresses are high, they tend to collapse. When these soils are subjected to a vertical stress of 420 kPa, the primary consolidation time is of the order of one minute for NH<sub>2</sub> (a silty soil) and about ten minutes for NH<sub>3 </sub>(a silty-clayed soil).
基金the National Natural Science Foundation of China (Grant No. 20674040)National Basic Research Program of China (Grant No. 2006CB705703)
文摘Here, we introduce a new type of molecular imprinted polymer (MIP) with immobilized assistant recognition polymer chains (ARPCs) to create effective recognition sites and with bacterial cloned protein as template for adsorbing the low content target protein from cell extract. In this work, cloned pig cyclophilin 18 (pCyP18), a peptidyl-prolyl cis/trans-isomerase, was used as template. The template protein was selectively assembled with ARPCs from their library, which consists of numerous limited length polymer chains with randomly distributed recognition sites of positively charged amino groups and immobilizing sites. These assemblies were adsorbed by porous microsphers and immobilized on them. After removing the template, binding sites complementary to the target protein in size, shape and the position of recognition groups were exposed, and their confirmation was preserved by the cross-linked structure. The synthesized MIP was used to adsorb the cellular pCyP18, and its proportional content was enriched more than hundred times. The extended experiment on imprinting bovine serum albumin (BSA) with ARPCs shows that this method is also suitable for large protein.
基金supported by the National Natural Science Foundation of China(No.52101165)the Inner Mongolia Science and Technology Major Project(No.2020ZD0010)the Key Research Program of the Chinese Academy of Sciences(No.ZDRW-CN-2021-3).
文摘The large and dense rare earth (RE)-oxide inclusions in high-oxygen RE metal increase the risk of producing variable properties in RE steel. Consequently, a self-developed electrolysis cell was utilized for the production of low-oxygen La/Ce mischmetal. The electrolysis process and the origin of oxygen in mischmetal were comprehensively investigated. The results indicate that the reaction between La/Ce oxide and fluoride molten salt results in the formation of La/Ce oxy-fluoride. The deposition of oxy-fluoride at the bottom of the electrolysis cell is the primary factor contributing to the increased oxygen content in mischmetal. The comprehensive influence of oxide addition quantity, feeding interval, and electrolysis temperature on oxygen content, purity, and current efficiency using the response surface methodology model is revealed. The results for industrial experiment show that the purity of mishcmetal reaches higher than 99.78 wt.%, the oxygen content of mischmetal is only 0.0047 wt.% and the current efficiency of the electrolysis process achieves 80.79% under the optimized parameters of 225 kg/d, 30 s and 1069 ℃. The findings offer valuable insights into the application of molten salt electrolysis for the production of low-oxygen mischmetal.
文摘A study was conducted to screen out the low-temperature tolerant Boro rice seedlings from November 2012 to January 2013 for facing the upcoming rice production challenge in Northwest Bangladesh. The experimental time was characterized by a prevailing low environmental temperature of below 15°C. Five rice cultivars (V1: BR-2;V2: BR-16;V3: Pariza;V4: Minicate;V5: BRRI dhan 50) were selected for the study. The leaf proline, chlorophyll content and total carotenoid content were investigated. The V2 (BR-16) seedling synthesized the higher leaf proline (1.228 g·g-1) at a low temperature than those of other tested cultivars. Again, the highest amount of chlorophyll-a (3.957 g·g-1), chlorophyll-b (2.118 g·g-1), chlorophyll-a/b ratio (3.6754 mg·g-1) and total chlorophyll (5.051 g·g-1) was measured in V2 (BR-16). The maximum total carotenoid (1.213 g·g-1) was also observed in V2. In this experiment, the V2 (BR-16) showed comparatively better potentiality to survive at low temperatures (below 15°C) than other varieties.
基金supported by C1 Gas Refinery Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science,ICT & Future Planning (2015M3D3A1A01064908)
文摘Alcohol-assisted low-temperature methanol synthesis was conducted over Cu/ZnO;catalysts while varying the copper content（X）. Unlike conventional methanol synthesis, ethanol acted as both solvent and reaction intermediate in this reaction, creating a different reaction pathway. The formation of crystalline phases and characteristic morphology of the co-precipitated precursors during the co-precipitation step were important factors in obtaining an efficient Cu/ZnO catalyst with a high dispersion of metallic copper,which is one of the main active sites for methanol synthesis. The acidic properties of the Cu/ZnO catalyst were also revealed as important factors, since alcohol esterification is considered the rate-limiting step in alcohol-assisted low-temperature methanol synthesis. As a consequence, bifunctionality of the Cu/ZnO catalyst such as metallic copper and acidic properties was required for this reaction. In this respect, the copper content（X） strongly affected the catalytic activity of the Cu/ZnO;catalysts, and accordingly, the Cu/ZnO;.5 catalyst with a high copper dispersion and sufficient acid sites exhibited the best catalytic performance in this reaction.
文摘To resolve the difficulty in slag formation during steelmaking with low silicon hot metal and to increase productivity, a new 5-hole lance was developed by increasing oxygen flow from 50 000 m^3/h to 60 000 m^3/h. Synthetic slag was added to adjust the slag composition. The problems such as difficulty in dephosphorization and slag adhesion to oxygen lance and hood were settled. Steel production and metal yield were increased and the nozzle life was prolonged through these techniques.
