The influence of yttrium on the corrosion behavior of Mg–Y alloys has been investigated by electrochemical measurements,scanning electron microscope(SEM)observation,X-ray diffraction(XRD),and X-ray photoelectron spec...The influence of yttrium on the corrosion behavior of Mg–Y alloys has been investigated by electrochemical measurements,scanning electron microscope(SEM)observation,X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS)analysis in NaCl solution.The corrosion resistance decreased with increasing Y content due to increasing Y-rich zone.The solid-dissolved Y improved the chemical activity of the substrate which promoted the corrosion reaction by forming Y2O3.The corrosion resistance was improved by increasing the Y concentration of matrix and proper net Y-rich structure.The sample has the best corrosion resistance when all the Y element was dissolved into the matrix of Mg–5Y in 0.1 M NaCl.展开更多
The rare earth elements and yttrium(REY)of the K2 coal from the Moxinpo mine,Chongqing,were determined using inductively coupled plasma mass spectrometry(ICP-MS).The results show that REY are enriched in the K2 coal,w...The rare earth elements and yttrium(REY)of the K2 coal from the Moxinpo mine,Chongqing,were determined using inductively coupled plasma mass spectrometry(ICP-MS).The results show that REY are enriched in the K2 coal,with the average content up to 462 lg/g,much higher than average values of most coals in the world.The REY distribution patterns indicate that the light REY is enriched and show a well-pronounced Eu minimum.The fractionation of individual light-REY is higher than that of the heavy-REY.The REY distribution through the K2 coal seam shows that the top and bottom portion of the coal seam have a lower content of REY than the middle portion.Goyazite and rhabdophane were identified with a scanning electron microscope equipped with an energy-dispersed X-ray spectrometer(SEM-EDX).The REY distributions through the coal seam,SEM-EDX data and the correlation analysis between ash yields and the concentrations have revealed that the REY mainly occurs in the organic matter.The K2 coal is a potential rare-metal resource due to its high REY contents,and the coal ash could be regarded as a new and promising raw material for recovery of REY as a by-product.展开更多
Ferromanganese nodules and crusts contain relatively high concentration of rare earth elements（REE） and yttrium（REY）,with a growing interest in exploitation as an alternative to land-based REY resources.On the bas...Ferromanganese nodules and crusts contain relatively high concentration of rare earth elements（REE） and yttrium（REY）,with a growing interest in exploitation as an alternative to land-based REY resources.On the basis of comprehensive geochemical approach,the abundance and distribution of REY in the ferromanganese nodules from the South China Sea are analyzed.The results indicate that the REY contents in ferromanganese deposits show a clear geographic regularity.Total REY contents range from 69.1×10^-6 to 2 919.4×10^-6,with an average value of 1 459.5×10^-6.Especially,the enrichment rate of Ce content is high,accounting for almost 60% of the total REY.This REE enrichment is controlled mainly by the sorption of ferromanganese oxides and clay minerals in the nodules and crusts.Moreover,the total REY are higher in ferromanganese deposits of hydrogenous origin than of diagenetic origin.Finally,Light REE（LREE） and heavy REE（HREE） oxides of the ferromanganese deposits in the study area can be classified into four grades： non-enriched type,weakly enriched type,enriched type,and extremely enriched type.According to the classification criteria of rare earth resources,the Xisha and Zhongsha platform-central deep basin areas show a great potential for these rare earth metals.展开更多
This study examines the rare earth elements and yttrium(REY)concentrations of twenty-five samples from the reef outcrop exposed along the Lianglitage Mountain in the Ordovician,Tarim Basin in China.The concentration a...This study examines the rare earth elements and yttrium(REY)concentrations of twenty-five samples from the reef outcrop exposed along the Lianglitage Mountain in the Ordovician,Tarim Basin in China.The concentration analysis provides constraints on the paleoenvironment during reef deposition.Based on the detailed sedimentology and petrographic work,we divide the reef facies into four sub-facies:the base facies,reef-core facies,reef-flank facies,and sealing facies.The geochemical data(such as major and trace elements,carbon and oxygen isotopes,and REYs)are further used to study the coeval seawater characteristics as well as potential diagenesis overprints.The result indicated that the diagenesis has little effect on the REY patterns of the reefal limestones.The REY concentrations of the reefal limestones are overall low(ranging from 3.69 to 19.60 ppm,arithmetic mean=10.22 ppm,SD=5.4).The PAAS-normalized REY patterns are consistently flat compared to the typical well-oxidized,shallow marine water patterns.However,the light REE(LREE)depletions,positive La anomalies,negative Ce anomalies and positive Y anomalies,suggest that these reefal limestones are likely an indicative of contemporaneous seawater REY signals.The seawater-like Y/Ho ratios(average at 37.51)further support that REY signals in these limestones are likely a reflection of seawater with little diagenetic modifications.The low Y/Ho ratios presented only in the reef-flank facies and sealing facies are likely a suggestion of detrital contamination.Hence,this study confirms that REY patterns of the limestones at the base facies and reef-core facies can record ancient seawater information,and reefs can be used as a potential geochemical proxy for paleoenvironment studies throughout the Earth’s history.展开更多
Determination of trace rare earth elements(REEs)in 99. 999% purity yttrium oxide using the inductively coupled plasma mass spectrometric technique (ICPMS) has been developed. Instrumental parameters and factors affeci...Determination of trace rare earth elements(REEs)in 99. 999% purity yttrium oxide using the inductively coupled plasma mass spectrometric technique (ICPMS) has been developed. Instrumental parameters and factors affecitng analytical results have been studied and then optimized.Samples are analyzed directly following an acid digestion without separation or preconcentration and with limit of detection of 0. 003～0. 02 ng/ml, precision of ±5. 4%(cofficient of variation)and recovery of 90～115%. Correction for isobaric interferences from oxide ions and hydroxide ions is made mathematically. Special internal standard procedures are used to compensate drift in metal:metal oxide ratios and sensitivity. The analytical results of several samples are accurate as compared with inductively coupled plasma atomic emission spectrometry (ICPAES) and spark source mass spectrometry (SSMS).展开更多
Microstructures of Cu-based alloys (including CuO.8CrO.05La, CuO.8CrO.lLa, CuO.8CrO.4La, CuO.8CrO.05Y, CuO.8CrO.lY and CuO.8CrO.4Y) were studied by optical microscope, X-ray diffractometer, Scanning electron microscop...Microstructures of Cu-based alloys (including CuO.8CrO.05La, CuO.8CrO.lLa, CuO.8CrO.4La, CuO.8CrO.05Y, CuO.8CrO.lY and CuO.8CrO.4Y) were studied by optical microscope, X-ray diffractometer, Scanning electron microscope and Energy-dispersive X-ray spectroscopy. The results show that La and Y refine the grains and change the distribution of microstructures of Cu-Cr alloys. The sizes of Cr particles are smaller in CuCrRE alloys than in CuCr alloy. In CuCrLa and CuCrY alloys, La and Y usually respectively exist as compounds of CugLa and Cu5Y. These compounds distribute in the grains with sphere shape and on the grain-boundaries with slice shape.展开更多
Round Top Mountain in Hudspeth County, west Texas, USA is a surface-exposed rhyolite intrusion enriched in Y and heavy rare earth elements （HREEs）, as well as Nb, Ta, Be, Li, F, Sn, Rb, Th, and U. The massive tonnag...Round Top Mountain in Hudspeth County, west Texas, USA is a surface-exposed rhyolite intrusion enriched in Y and heavy rare earth elements （HREEs）, as well as Nb, Ta, Be, Li, F, Sn, Rb, Th, and U. The massive tonnage, estimated at well over 1 billion tons, of the deposit makes it a target for recovery of valuable yttrium and HREEs （YHREEs）, and possibly other scarce ele-ments. Because of the extremely fine grain size of the mineralized rhyolite matrix, it has not been clear which minerals host the YHREEs and in what proportions. REE-bearing minerals reported in the deposit included bastn？site-Ce, Y-bearing fluorite, xeno-time-Y, zircon, aeschynite-Ce, a Ca-Th-Pb fluoride, and possibly ancylite-La and cerianite-Ce. Extended X-ray absorption fine struc-ture （EXAFS） indicated that virtually all of the yttrium, a proxy for the HREEs, resided in a coordination in the fluorite-type crystal structure, rather than those in the structures of bastn？site-Ce and xenotime-Y. The YREE grade of the Round Top deposit was just over 0.05%, with 72%of this consisting of YHREEs. This grade was in the range of the South China ionic clay deposits that supply essentially all of the world’s YHREEs. Because the host Y-bearing fluorite is soluble in dilute sulfuric acid at room temperature, a heap leaching of the deposit appeared feasible, aided by the fact that 90%-95%of the rock consists of unreactive and insoluble feld-spars and quartz. The absence of overburden, remarkable consistency of mineralization grade throughout the massive rhyolite, prox-imity （a few km） to a US interstate highway, major rail systems and gas and electricity, temperate climate, and stable political location in the world’s largest economy all enhanced the potential economic appeal of Round Top.展开更多
Objective The aim of this study was to assess the effects of yttrium nitrate on neurobehaviora development in Sprague-Dawley rats. Methods Dams were orally exposed to 0, 5, 15, or 45 mg/kg daily of yttrium nitrate fro...Objective The aim of this study was to assess the effects of yttrium nitrate on neurobehaviora development in Sprague-Dawley rats. Methods Dams were orally exposed to 0, 5, 15, or 45 mg/kg daily of yttrium nitrate from gestation day （GD） 6 to postnatal day （PND） 21. Body weight and food consumption were monitored weekly. Neurobehavior was assessed by developmental landmarks and reflexes, motor activity, hot plate, Rota-rod and cognitive tests. Additionally, brain weights were measured on PND 21 and 70. Results No significant difference was noted among all groups for maternal body weight and food consumption. All yttrium-exposed offspring showed an increase in body weight on PND 21; however, no significant difference in body weight for exposed pups versus controls was observed 2 weeks or more after the yttrium solution was discontinued. The groups given 5 mg/kg daily decreased significantly in the duration of female forelime grip strength and ambulation on PND 13. There was no significant difference between yttrium-exposed offspring and controls with respect to other behavioral ontogeny parameters and postnatal behavioral test results. Conclusion Exposure of rats to yttrium nitrate in concentrations up to 45 mg/kg daily had no adverse effects on their neurobehavioral development.展开更多
Yttrium is a main kind of rare earth elements （REEs） with wide applications in modem industry and farming. Lead has been considered to be one of the most important heavy metal pollutants due to its environmental per...Yttrium is a main kind of rare earth elements （REEs） with wide applications in modem industry and farming. Lead has been considered to be one of the most important heavy metal pollutants due to its environmental persistence and tendency. In order to clarify the effects of REEs on cyanobacteria in case of suffering heavy metal pollutants, we investigated the effect of different concentrations of yttrium ion （y3＋） on the common blue-green microalgae Microcystis aeruginosa, grown under conditions of lead ion （Pb2＋） stress. Growth and physiological status were tested involving several important enzyme of antioxidant defense system （superoxide dismutase （SOD）, peroxidase （POD）, catalase （CAT）, malondiadehyde （MDA）, chlorophyll a （Chl-a）, soluble sugar and Microcystin-LR （MC-LR） in cultured experiments. Results indicated that growth ofM. aeruginosa was stimulated when treated less than 0.50 mg/L y3-and 0.20 mg/L is the optimum concentration. With the increasing content of Chl-a and activity of SOD, POD, CAT at the 12th day at relatively low concentration of y3＋ treatment （〈0.20 mg/L）, enhancement of photosynthesis and the improvement of eliminating active oxygen on M. aeruginosa were observed. On the contrast, soluble sugar content on algae reduced as the treatment of initial y3＋ concentration was in the range of 0.00-0.50 mg/L. Besides, there was a significant accumulation in both contents of MDA and MC-LR exposed from 1.00 to 5.00 mg/L y3＋, indicating that the ruin of antioxidant defense system and further aggravation to the existence of algal cell may be due to MC-LR releasing. M. aeruginosa might suffer a more positive physiological impact for exposure of relatively low y3＋ concentration against Pb2＋ stress harm, which provided a far-reaching significance on blue-green algae research.展开更多
There is no doubt that rare earth elements stand an important position among the essential elements of plant growth and it is long time since they are first used as plant growth promoters. Given their effects on micro...There is no doubt that rare earth elements stand an important position among the essential elements of plant growth and it is long time since they are first used as plant growth promoters. Given their effects on microstructure, most reports are focused on the toxicology rather than promotion. Using cucumis sativus L. (Jin Chun No.5) as experiment material, we try to find out the nutritional effects of low Y3+ concentrations on cucumber seedlings′ leaves. The present paper suggests that the rare earth elements act as micronutrients at low concentrations while they give rise to toxicity at high concentration. Benefits defeat toxicity with concentration ranging from 5 to 25 μmol·L-1. Through careful study, at the Y(NO3)3 concentration of 10 μmol·L-1 the content of chlorophyll as well as the activities of SOD, Cu-Zn SOD and the POD are the highest. It indicates 10 μmol·L-1 is the optimum concentration of yttrium for promoting the cucumber growth.展开更多
The effect of RE element Y on the microstructure and properties of Ti(C,N)-based cermet has been investigated. Yttrium can refine the particles of carbide phase because itcan purify the interface between binder phase ...The effect of RE element Y on the microstructure and properties of Ti(C,N)-based cermet has been investigated. Yttrium can refine the particles of carbide phase because itcan purify the interface between binder phase and carbide phase, and increase the thickness of rimphase slightly. The effect is in the most evidence when the mass fraction of Y is 0.8 percent andwhen the transverse rapture strength and the hardness of Ti(C, N)-based cermet are maximal.展开更多
目的近零折射率(index near zero,INZ)模式在光通信和物理诊疗等领域展现出巨大应用潜力,但其调制通常依赖复杂的实验手段,这限制了其更广泛的应用。因此,设计并验证灵活可调的INZ模式及其应用场景在当下尤为重要。方法本研究提出两种...目的近零折射率(index near zero,INZ)模式在光通信和物理诊疗等领域展现出巨大应用潜力,但其调制通常依赖复杂的实验手段,这限制了其更广泛的应用。因此,设计并验证灵活可调的INZ模式及其应用场景在当下尤为重要。方法本研究提出两种基于钇铁石榴石(yttrium iron garnet,YIG)的亚波长磁光单向波导,通过理论分析波导结构中表面模式的色散曲线与波导参数的关系,明确调控INZ模式的理论并通过有限元法等技术验证理论结果。结果研究发现了新颖的宽带可调谐INZ模式。这些模式的频率明确依赖于外部磁场,具有可预测且精确可调的特性。基于此,本团队通过简单调控外部磁场,设计了宽带可调谐全光相位调控器及一种慢波INZ装置,并创新性地提出了一种基于可调控INZ模式的微波热疗理论。结论本团队设计的单向波导中的INZ模式具有可调控性和宽带的特性,利用单向INZ模式实现的功能器件为小型化全光通信和计算提供了新的可能性,也可用于如非介入式可控微波热疗等医疗领域。展开更多
基金the National Basic Research Program of China(grant number:2013CB632205)National Natural Science Foundation of China(grant number:51501199).
文摘The influence of yttrium on the corrosion behavior of Mg–Y alloys has been investigated by electrochemical measurements,scanning electron microscope(SEM)observation,X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS)analysis in NaCl solution.The corrosion resistance decreased with increasing Y content due to increasing Y-rich zone.The solid-dissolved Y improved the chemical activity of the substrate which promoted the corrosion reaction by forming Y2O3.The corrosion resistance was improved by increasing the Y concentration of matrix and proper net Y-rich structure.The sample has the best corrosion resistance when all the Y element was dissolved into the matrix of Mg–5Y in 0.1 M NaCl.
基金This research was supported by the National Key Basic Research and Development Program(No.2014CB238902)National Natural Science Foundation of China(No.41302128).
文摘The rare earth elements and yttrium(REY)of the K2 coal from the Moxinpo mine,Chongqing,were determined using inductively coupled plasma mass spectrometry(ICP-MS).The results show that REY are enriched in the K2 coal,with the average content up to 462 lg/g,much higher than average values of most coals in the world.The REY distribution patterns indicate that the light REY is enriched and show a well-pronounced Eu minimum.The fractionation of individual light-REY is higher than that of the heavy-REY.The REY distribution through the K2 coal seam shows that the top and bottom portion of the coal seam have a lower content of REY than the middle portion.Goyazite and rhabdophane were identified with a scanning electron microscope equipped with an energy-dispersed X-ray spectrometer(SEM-EDX).The REY distributions through the coal seam,SEM-EDX data and the correlation analysis between ash yields and the concentrations have revealed that the REY mainly occurs in the organic matter.The K2 coal is a potential rare-metal resource due to its high REY contents,and the coal ash could be regarded as a new and promising raw material for recovery of REY as a by-product.
基金The National Natural Science Foundation of China under contract Nos 41376057,41306047,41676056the Spanish project SUBVENT under contract No.CGL2012-39524-C02
文摘Ferromanganese nodules and crusts contain relatively high concentration of rare earth elements（REE） and yttrium（REY）,with a growing interest in exploitation as an alternative to land-based REY resources.On the basis of comprehensive geochemical approach,the abundance and distribution of REY in the ferromanganese nodules from the South China Sea are analyzed.The results indicate that the REY contents in ferromanganese deposits show a clear geographic regularity.Total REY contents range from 69.1×10^-6 to 2 919.4×10^-6,with an average value of 1 459.5×10^-6.Especially,the enrichment rate of Ce content is high,accounting for almost 60% of the total REY.This REE enrichment is controlled mainly by the sorption of ferromanganese oxides and clay minerals in the nodules and crusts.Moreover,the total REY are higher in ferromanganese deposits of hydrogenous origin than of diagenetic origin.Finally,Light REE（LREE） and heavy REE（HREE） oxides of the ferromanganese deposits in the study area can be classified into four grades： non-enriched type,weakly enriched type,enriched type,and extremely enriched type.According to the classification criteria of rare earth resources,the Xisha and Zhongsha platform-central deep basin areas show a great potential for these rare earth metals.
基金supported by the National Natural Science Foundation of China(grant number 51574208)the National 973 Program of China(grant number 2012CB214802)+1 种基金the China Geological Survery Project(grant number DD20190217)the China Scholar Council(grant number 201606400023)for providing the financial support
文摘This study examines the rare earth elements and yttrium(REY)concentrations of twenty-five samples from the reef outcrop exposed along the Lianglitage Mountain in the Ordovician,Tarim Basin in China.The concentration analysis provides constraints on the paleoenvironment during reef deposition.Based on the detailed sedimentology and petrographic work,we divide the reef facies into four sub-facies:the base facies,reef-core facies,reef-flank facies,and sealing facies.The geochemical data(such as major and trace elements,carbon and oxygen isotopes,and REYs)are further used to study the coeval seawater characteristics as well as potential diagenesis overprints.The result indicated that the diagenesis has little effect on the REY patterns of the reefal limestones.The REY concentrations of the reefal limestones are overall low(ranging from 3.69 to 19.60 ppm,arithmetic mean=10.22 ppm,SD=5.4).The PAAS-normalized REY patterns are consistently flat compared to the typical well-oxidized,shallow marine water patterns.However,the light REE(LREE)depletions,positive La anomalies,negative Ce anomalies and positive Y anomalies,suggest that these reefal limestones are likely an indicative of contemporaneous seawater REY signals.The seawater-like Y/Ho ratios(average at 37.51)further support that REY signals in these limestones are likely a reflection of seawater with little diagenetic modifications.The low Y/Ho ratios presented only in the reef-flank facies and sealing facies are likely a suggestion of detrital contamination.Hence,this study confirms that REY patterns of the limestones at the base facies and reef-core facies can record ancient seawater information,and reefs can be used as a potential geochemical proxy for paleoenvironment studies throughout the Earth’s history.
文摘Determination of trace rare earth elements(REEs)in 99. 999% purity yttrium oxide using the inductively coupled plasma mass spectrometric technique (ICPMS) has been developed. Instrumental parameters and factors affecitng analytical results have been studied and then optimized.Samples are analyzed directly following an acid digestion without separation or preconcentration and with limit of detection of 0. 003～0. 02 ng/ml, precision of ±5. 4%(cofficient of variation)and recovery of 90～115%. Correction for isobaric interferences from oxide ions and hydroxide ions is made mathematically. Special internal standard procedures are used to compensate drift in metal:metal oxide ratios and sensitivity. The analytical results of several samples are accurate as compared with inductively coupled plasma atomic emission spectrometry (ICPAES) and spark source mass spectrometry (SSMS).
基金supported by the Foundation for University Key Teacher by the Ministry of Education of China under Contract No.GG 430-11902-1010the Natural Science Foundation of Jiangxi,China under Contract No.0050022.
文摘Microstructures of Cu-based alloys (including CuO.8CrO.05La, CuO.8CrO.lLa, CuO.8CrO.4La, CuO.8CrO.05Y, CuO.8CrO.lY and CuO.8CrO.4Y) were studied by optical microscope, X-ray diffractometer, Scanning electron microscope and Energy-dispersive X-ray spectroscopy. The results show that La and Y refine the grains and change the distribution of microstructures of Cu-Cr alloys. The sizes of Cr particles are smaller in CuCrRE alloys than in CuCr alloy. In CuCrLa and CuCrY alloys, La and Y usually respectively exist as compounds of CugLa and Cu5Y. These compounds distribute in the grains with sphere shape and on the grain-boundaries with slice shape.
基金Project supported by Research Contracts 26-8211-12 and 26-8211-16 between Texas Rare Earth Resources,Inc.and the University of Texas at El Paso
文摘Round Top Mountain in Hudspeth County, west Texas, USA is a surface-exposed rhyolite intrusion enriched in Y and heavy rare earth elements （HREEs）, as well as Nb, Ta, Be, Li, F, Sn, Rb, Th, and U. The massive tonnage, estimated at well over 1 billion tons, of the deposit makes it a target for recovery of valuable yttrium and HREEs （YHREEs）, and possibly other scarce ele-ments. Because of the extremely fine grain size of the mineralized rhyolite matrix, it has not been clear which minerals host the YHREEs and in what proportions. REE-bearing minerals reported in the deposit included bastn？site-Ce, Y-bearing fluorite, xeno-time-Y, zircon, aeschynite-Ce, a Ca-Th-Pb fluoride, and possibly ancylite-La and cerianite-Ce. Extended X-ray absorption fine struc-ture （EXAFS） indicated that virtually all of the yttrium, a proxy for the HREEs, resided in a coordination in the fluorite-type crystal structure, rather than those in the structures of bastn？site-Ce and xenotime-Y. The YREE grade of the Round Top deposit was just over 0.05%, with 72%of this consisting of YHREEs. This grade was in the range of the South China ionic clay deposits that supply essentially all of the world’s YHREEs. Because the host Y-bearing fluorite is soluble in dilute sulfuric acid at room temperature, a heap leaching of the deposit appeared feasible, aided by the fact that 90%-95%of the rock consists of unreactive and insoluble feld-spars and quartz. The absence of overburden, remarkable consistency of mineralization grade throughout the massive rhyolite, prox-imity （a few km） to a US interstate highway, major rail systems and gas and electricity, temperate climate, and stable political location in the world’s largest economy all enhanced the potential economic appeal of Round Top.
基金financially supported by the National Science and Technology Support Program(2012BAK01B00)
文摘Objective The aim of this study was to assess the effects of yttrium nitrate on neurobehaviora development in Sprague-Dawley rats. Methods Dams were orally exposed to 0, 5, 15, or 45 mg/kg daily of yttrium nitrate from gestation day （GD） 6 to postnatal day （PND） 21. Body weight and food consumption were monitored weekly. Neurobehavior was assessed by developmental landmarks and reflexes, motor activity, hot plate, Rota-rod and cognitive tests. Additionally, brain weights were measured on PND 21 and 70. Results No significant difference was noted among all groups for maternal body weight and food consumption. All yttrium-exposed offspring showed an increase in body weight on PND 21; however, no significant difference in body weight for exposed pups versus controls was observed 2 weeks or more after the yttrium solution was discontinued. The groups given 5 mg/kg daily decreased significantly in the duration of female forelime grip strength and ambulation on PND 13. There was no significant difference between yttrium-exposed offspring and controls with respect to other behavioral ontogeny parameters and postnatal behavioral test results. Conclusion Exposure of rats to yttrium nitrate in concentrations up to 45 mg/kg daily had no adverse effects on their neurobehavioral development.
文摘Yttrium is a main kind of rare earth elements （REEs） with wide applications in modem industry and farming. Lead has been considered to be one of the most important heavy metal pollutants due to its environmental persistence and tendency. In order to clarify the effects of REEs on cyanobacteria in case of suffering heavy metal pollutants, we investigated the effect of different concentrations of yttrium ion （y3＋） on the common blue-green microalgae Microcystis aeruginosa, grown under conditions of lead ion （Pb2＋） stress. Growth and physiological status were tested involving several important enzyme of antioxidant defense system （superoxide dismutase （SOD）, peroxidase （POD）, catalase （CAT）, malondiadehyde （MDA）, chlorophyll a （Chl-a）, soluble sugar and Microcystin-LR （MC-LR） in cultured experiments. Results indicated that growth ofM. aeruginosa was stimulated when treated less than 0.50 mg/L y3-and 0.20 mg/L is the optimum concentration. With the increasing content of Chl-a and activity of SOD, POD, CAT at the 12th day at relatively low concentration of y3＋ treatment （〈0.20 mg/L）, enhancement of photosynthesis and the improvement of eliminating active oxygen on M. aeruginosa were observed. On the contrast, soluble sugar content on algae reduced as the treatment of initial y3＋ concentration was in the range of 0.00-0.50 mg/L. Besides, there was a significant accumulation in both contents of MDA and MC-LR exposed from 1.00 to 5.00 mg/L y3＋, indicating that the ruin of antioxidant defense system and further aggravation to the existence of algal cell may be due to MC-LR releasing. M. aeruginosa might suffer a more positive physiological impact for exposure of relatively low y3＋ concentration against Pb2＋ stress harm, which provided a far-reaching significance on blue-green algae research.
基金Project supported by Scientific Grant of TianJin Normal University (1CHS02B)Special Grant of the President of TianJin Normal University
文摘There is no doubt that rare earth elements stand an important position among the essential elements of plant growth and it is long time since they are first used as plant growth promoters. Given their effects on microstructure, most reports are focused on the toxicology rather than promotion. Using cucumis sativus L. (Jin Chun No.5) as experiment material, we try to find out the nutritional effects of low Y3+ concentrations on cucumber seedlings′ leaves. The present paper suggests that the rare earth elements act as micronutrients at low concentrations while they give rise to toxicity at high concentration. Benefits defeat toxicity with concentration ranging from 5 to 25 μmol·L-1. Through careful study, at the Y(NO3)3 concentration of 10 μmol·L-1 the content of chlorophyll as well as the activities of SOD, Cu-Zn SOD and the POD are the highest. It indicates 10 μmol·L-1 is the optimum concentration of yttrium for promoting the cucumber growth.
文摘The effect of RE element Y on the microstructure and properties of Ti(C,N)-based cermet has been investigated. Yttrium can refine the particles of carbide phase because itcan purify the interface between binder phase and carbide phase, and increase the thickness of rimphase slightly. The effect is in the most evidence when the mass fraction of Y is 0.8 percent andwhen the transverse rapture strength and the hardness of Ti(C, N)-based cermet are maximal.
文摘目的近零折射率(index near zero,INZ)模式在光通信和物理诊疗等领域展现出巨大应用潜力,但其调制通常依赖复杂的实验手段,这限制了其更广泛的应用。因此,设计并验证灵活可调的INZ模式及其应用场景在当下尤为重要。方法本研究提出两种基于钇铁石榴石(yttrium iron garnet,YIG)的亚波长磁光单向波导,通过理论分析波导结构中表面模式的色散曲线与波导参数的关系,明确调控INZ模式的理论并通过有限元法等技术验证理论结果。结果研究发现了新颖的宽带可调谐INZ模式。这些模式的频率明确依赖于外部磁场,具有可预测且精确可调的特性。基于此,本团队通过简单调控外部磁场,设计了宽带可调谐全光相位调控器及一种慢波INZ装置,并创新性地提出了一种基于可调控INZ模式的微波热疗理论。结论本团队设计的单向波导中的INZ模式具有可调控性和宽带的特性,利用单向INZ模式实现的功能器件为小型化全光通信和计算提供了新的可能性,也可用于如非介入式可控微波热疗等医疗领域。
