[Objective]This study aimed at exploring the physiological properties of the known Cd hyperaccumulator Viola baoshanensis and the control plant Viola inconspicua to cadmium stress.[Method]After a hydroponic experiment...[Objective]This study aimed at exploring the physiological properties of the known Cd hyperaccumulator Viola baoshanensis and the control plant Viola inconspicua to cadmium stress.[Method]After a hydroponic experiment carried in a greenhouse,plant Cd accumulations,root elongation rates,MDA contents,and antioxidant enzyme activities were determinined.[Result]Both Viola baoshanensis and Viola inconspicua showed high levels of Cd uptake growing in Cd-supplemented solution of 300 μmol/L for 12 d with Cd accumulations of 2 595 and 3 330 mg/kg in the shoots,respectively.In the cultural solution supplemented with 300 μmol/L of Cd,the root elongation rates were not affected and the MDA contents decreased significantly in Viola baoshanensis,while the root elongation rates were significantly inhibited and the MDA contents increased remarkably in Viola inconspicua,which indicated that Viola baoshanensis had the higher Cd tolerance.The superoxide dismutase（SOD）,peroxidase（POD）and catalase（CAT）activities of two Viola species were not linearly related to the middle and low Cd-supplemented concentrations（5,50 μmol/L）and had attained the tiptop in cultural solution supplemented with 100 or 300 μmol/L of Cd but declined in cultural solution supplemented with 500 μmol/L of Cd,suggesting that the contribution of antioxidative enzymes was limited to the Cd tolerance of Viola plants.The Viola inconspicua showed a strong adaptability to the middle and low concentrations of Cd.[Conclusion]Viola species could be used as potential plant resources for the phytoremediation of agriculture areas polluted with low and even middle levels of Cd.展开更多
Guizhou Province is part of the glutinous rice cultivation sphere in our country.Its rice production and germplasm resources play an important role.The southeast region is the centre of the Guizhou glutinous rice cult...Guizhou Province is part of the glutinous rice cultivation sphere in our country.Its rice production and germplasm resources play an important role.The southeast region is the centre of the Guizhou glutinous rice cultivation and characterized by waxy wo,which is treasure of the original farming culture of southeast Guizhou region and an important symbol for ethnic cultural identity of the region.展开更多
Baoji City develops much faster recently, and much progress has made on urbanization. On the other hand, urbanization has been closely linked to use of land resources, for city expansion relies on lands. According to ...Baoji City develops much faster recently, and much progress has made on urbanization. On the other hand, urbanization has been closely linked to use of land resources, for city expansion relies on lands. According to the 6th demographic census of Baoji and land survey in 2009, the research analyzed problems in urbanization of Baoji and concluded that urbanization proceeds well, as well as land intensified use. Still, the problems can never be ignored, such as poor land quality,decreasing farmland, low land use ratio and intensive use degree, slow optimization process of land use structure, more limiting factors of land development and use,heavier eco-environment protection tasks. Additionally, the research proposed specific countermeasures based on status quo of land use.展开更多
Gallium oxide （Ga203） films were deposited on singlecrystalline sapphire （0001） substrate by radio frequency （RF） magnetron sputtering technique in the temperature range of 300--500 ℃. The microstructure of the...Gallium oxide （Ga203） films were deposited on singlecrystalline sapphire （0001） substrate by radio frequency （RF） magnetron sputtering technique in the temperature range of 300--500 ℃. The microstructure of the fl-Ga203 films were investigated in detail using X-ray diffractometer （XRD） and scanning electron microscope （SEM）. The results show that the film prepared at 500℃ exhibits the best crystallinity with a monoclinic structure （fl-Ga203）. Structure analysis reveals a clear out-of-plane orientation offl-Ga203 （201） II A1203 （0001）. The average transmittance of these films in the visible wavelength range exceeds 90%, and the optical band gap of the films varies from 4.68 eV to 4.94 eV which were measured by an ultraviolet-visible-near infrared （UV-vis-NIR） spectrophotometer. Therefore, it is hopeful that the fl-Ga203 film can be used in the UV optoelectronic devices.展开更多
A scalable approach to obtaining high-density, large-area single-walled carbon nanotube （SWNT） arrays is essential for realizing the full potential of SWNTs in practical electronic devices; this is still a great cha...A scalable approach to obtaining high-density, large-area single-walled carbon nanotube （SWNT） arrays is essential for realizing the full potential of SWNTs in practical electronic devices; this is still a great challenge. Here, we report an improved synthetic method for large-area growth of ultra-high-density SWNT arrays on sapphire surfaces by combining Trojan catalysts （released from the substrate, to assure ultra-high density） with Mo nanoparticles （loaded on the surface, to stabilize the released Trojan catalysts） as cooperating catalysts. Dense and perfectly aligned SWNTs covered the entire substrate and the local density was as high as 160 tubes/pro. Field-effect transistors （FETs） built on such arrays gave an output current density of -488 μA/μm at the drain-source voltage （Vds） = the gate-source voltage （Vgs） = -2 V, corresponding to an on-conductance per width of 244 μS/μm. These results confirm the wide range of potential applications of Trojan-Mo catalysts in the structure-controlled growth of SWNTs.展开更多
One judiciously designed strategy of utilizing an ultrathin but conductive Ga_(2)O_(3):Si nanolayer to prepare(AlGa)_(2)O_(3)crystalline film is demonstrated.Benefiting from the existence of Ga_(2)O_(3):Si nanolayer,a...One judiciously designed strategy of utilizing an ultrathin but conductive Ga_(2)O_(3):Si nanolayer to prepare(AlGa)_(2)O_(3)crystalline film is demonstrated.Benefiting from the existence of Ga_(2)O_(3):Si nanolayer,a high-quality(Al_(0.68)Ga_(0.32))_(2)O_(3)sesquioxide film with 68 at.%aluminum was epitaxially grown on sapphire substrates,which was characterized by high-resolution transmission electron microscopy,X-ray photoelectron spectroscopy and X-ray diffraction.Its bandgap was broadened to 6.14 eV,and a vacuum ultraviolet(VUV)(AlGa)_(2)O_(3)/Ga_(2)O_(3):Si photodetector was subsequently fabricated.The detector exhibits a pretty high on-off ratio of about 10^(3),an open-circuit voltage of 1.0 V and a responsivity of 8.1 mA W^(-1) at 0 V bias voltage.The performances imply that the proposed strategy is valuable for improving the quality and also adjusting the bandgap of(AlGa)_(2)O_(3)sesquioxides,which is expected to facilitate their application in VUV photodetection.展开更多
Compared to traditional optical domes, domes of sapphire coated with films can effectively reduce emissivity and increase transmittance. The purpose of this work is to investigate the thermal radiation effect on sapph...Compared to traditional optical domes, domes of sapphire coated with films can effectively reduce emissivity and increase transmittance. The purpose of this work is to investigate the thermal radiation effect on sapphire optical dome coated with yttrium oxide by a radio frequency mag- netron sputtering method. The emissivity of sapphire coated with Y203 films is studied by both numerical and experi- mental methods. The results indicate that the emissivity of sapphire substrate is reduced effectively with increasing the thickness of the Y203 film. In addition, a finite element model is developed to simulate the radiation intensity of the optical dome. The thermal responses indicate that the max- imum temperature is reduced apparently compared with the uncoated sapphire as Y203 film thicknesses increase. The average irradiance distribution at different film thicknesses with time shows that the self-thermal radiation disturbance of sapphire optical dome delays 0.93 s when the thickness of Y203 film is 200μm, which can guarantee the dome works properly and effectively even in a harsh environment.展开更多
The Baoshan Block is tectonically located in the middle segment of the Sibumasu plate. Granitic magmatism within the Baoshan Block has been considered weakly active due mainly to very limited exposures during the Hima...The Baoshan Block is tectonically located in the middle segment of the Sibumasu plate. Granitic magmatism within the Baoshan Block has been considered weakly active due mainly to very limited exposures during the Himalaya orogenic episode. The geochronological study on the buried Shuangmaidi granite has confirmed the existence of the Cenozoic granitoids in the Baoshan Block. The present study indicates that： （1） It is medium- to coarse-grained two mica phyric granite, characterized by high SiO2 （73.55%-77.16%） and low CaO （0.34%-1.38%） contents, with a total alkalis （K2O＋Na2O） of 5.22%-8.03%, K2O/Na2O ratios of 0.24-1.79, and total rare earth elements （ZREE） of the granite between 85 and 125 ppb. All samples are enriched in light REE and exhibit medium negative Eu anomalies; and they show pronounced negative anomalies in Ba, Sr, Ti, and Nb but significant positive anomalies in K, Rb, U, Th, and Pb on mantle-normalized trace element patterns, indicating typi-cally peraluminous to strongly peraluminous S-type granite. （2） The zircon SHRIMP U-Pb ages of the granite are 36.27±0.48 Ma for the samples from ZK7-1 and 35.78±0.49 Ma for those from ZK0-1, respectively. The similar zircon ages from these two drill cores may suggest that the granite samples come from the same buried pluton. （3） 206pb/204pb values of the granite vary from 20.115 to 25.359, 207pb/204pb from 15.776 to 16.160, and 208pb/204pb from 39.236 to 41.285, showing the characteristics of radio- active lead anomaly of the upper crust. The （87Sr/86Sr）i values calculated on the average age of the two-mica orthoclase granite （36 Ma） range from 0.72524 to 0.77503 and eNd（t） values vary from -10.9 to -11.7. These data, along with the depleted-mantle Nd modal ages of 1.73-1.80 Ga, imply that the granites might have formed from partial melting of the Precambrian crystal basements. （4） On the Hf-Rb-Ta diagram, almost all the samples fall within the field of post-collision tectonic setting. The CaO/Na2O and A1203/TiO2 ratios suggest that the granitic magma may have formed from partial melting of clay-rich crustal materials with a pos- sible melting temperature of about 900℃ and a possible crystallization temperature of 775-795~C. （5） During the post-collision of the Himalaya orogen, with the southeastward extrusion of the Indochina continent resulting from the continuous northward indentation of the India continent into the Asia, the Gaoligong Fault, as the western boundary of the Indochina continent, moved in the dextral strike-slip on a large scale to trigger partial melting of the thickened crust, and the peraluminous granitic magma from which the Shuangmaidi two-mica orthoclase granite derived was formed.展开更多
Nonpolar a-plane （1120） GaN films have been grown on r-plane （1102） sapphire by metal-organic chemical vapor deposition （MOCVD） under different growth pressures. The as-grown films are investigated by optical mi...Nonpolar a-plane （1120） GaN films have been grown on r-plane （1102） sapphire by metal-organic chemical vapor deposition （MOCVD） under different growth pressures. The as-grown films are investigated by optical microscopy, high-resolution X-ray diffraction （HRXRD） and Raman scattering. As growth pressure rises from 100 mbar to 400 mbar, the surface gets rougher, and the in-plane XRD full width at half maximum （FWHM） along the c-axis [0001] increases while that along the m-axis [1100] decreases. Meanwhile, residential stresses are reduced along both the c-axis and the m-axis. The structural anisotropy feature under 400 mbar is inverted with respect to 100 mbar, and the weakened anisotropy is achieved under a moderate pressure of 200 mbar, probably due to the suppressed Ga atomic migration along the c-axis under a larger pressure. We propose that pressure can affect a-plane growth through the V/III ratio.展开更多
基金Supported by National Natural Science Foundation of China(30400053,30900158)the Open Project of State Key Laboratory of Biocontrol of Sun Yat-sen University(SKLBC2010K04)~~
文摘[Objective]This study aimed at exploring the physiological properties of the known Cd hyperaccumulator Viola baoshanensis and the control plant Viola inconspicua to cadmium stress.[Method]After a hydroponic experiment carried in a greenhouse,plant Cd accumulations,root elongation rates,MDA contents,and antioxidant enzyme activities were determinined.[Result]Both Viola baoshanensis and Viola inconspicua showed high levels of Cd uptake growing in Cd-supplemented solution of 300 μmol/L for 12 d with Cd accumulations of 2 595 and 3 330 mg/kg in the shoots,respectively.In the cultural solution supplemented with 300 μmol/L of Cd,the root elongation rates were not affected and the MDA contents decreased significantly in Viola baoshanensis,while the root elongation rates were significantly inhibited and the MDA contents increased remarkably in Viola inconspicua,which indicated that Viola baoshanensis had the higher Cd tolerance.The superoxide dismutase（SOD）,peroxidase（POD）and catalase（CAT）activities of two Viola species were not linearly related to the middle and low Cd-supplemented concentrations（5,50 μmol/L）and had attained the tiptop in cultural solution supplemented with 100 or 300 μmol/L of Cd but declined in cultural solution supplemented with 500 μmol/L of Cd,suggesting that the contribution of antioxidative enzymes was limited to the Cd tolerance of Viola plants.The Viola inconspicua showed a strong adaptability to the middle and low concentrations of Cd.[Conclusion]Viola species could be used as potential plant resources for the phytoremediation of agriculture areas polluted with low and even middle levels of Cd.
基金Supported by General Humanity and Social Science Research Fundfrom Ministry of Education in 2009(09XJC770001)~~
文摘Guizhou Province is part of the glutinous rice cultivation sphere in our country.Its rice production and germplasm resources play an important role.The southeast region is the centre of the Guizhou glutinous rice cultivation and characterized by waxy wo,which is treasure of the original farming culture of southeast Guizhou region and an important symbol for ethnic cultural identity of the region.
基金Supported by National Social Science Fund Project(07XZZ006)Shaanxi Key laboratory project of the Education Department(11JS011)+5 种基金The 12th Planning Topic of Education Science in Shaanxi Province(SGH140676)Baoji Science and Technology Planning Program(14SFGG-2)Key Program of Baoji University of Arts and Sciences(ZK12050)Key Subject Funds of Shaanxi Province of Physical Geography of Baoji University of Arts and SciencesNational Undergraduate Training Program for Innovation and Entrepreneurship(201410721029)Shaanxi Undergraduate Training Program for Innovation and Entrepreneurship(2014S1716)~~
文摘Baoji City develops much faster recently, and much progress has made on urbanization. On the other hand, urbanization has been closely linked to use of land resources, for city expansion relies on lands. According to the 6th demographic census of Baoji and land survey in 2009, the research analyzed problems in urbanization of Baoji and concluded that urbanization proceeds well, as well as land intensified use. Still, the problems can never be ignored, such as poor land quality,decreasing farmland, low land use ratio and intensive use degree, slow optimization process of land use structure, more limiting factors of land development and use,heavier eco-environment protection tasks. Additionally, the research proposed specific countermeasures based on status quo of land use.
基金supported by the National Natural Science Foundation of China(Nos.61274113,61404091,61505144,51502203 and 51502204)the Opening Fund of Key Laboratory of Silicon Device Technology in Chinese Academy of Sciencesthe Tianjin Natural Science Foundation(Nos.14JCZDJC31500 and 14JCQNJC00800)
文摘Gallium oxide （Ga203） films were deposited on singlecrystalline sapphire （0001） substrate by radio frequency （RF） magnetron sputtering technique in the temperature range of 300--500 ℃. The microstructure of the fl-Ga203 films were investigated in detail using X-ray diffractometer （XRD） and scanning electron microscope （SEM）. The results show that the film prepared at 500℃ exhibits the best crystallinity with a monoclinic structure （fl-Ga203）. Structure analysis reveals a clear out-of-plane orientation offl-Ga203 （201） II A1203 （0001）. The average transmittance of these films in the visible wavelength range exceeds 90%, and the optical band gap of the films varies from 4.68 eV to 4.94 eV which were measured by an ultraviolet-visible-near infrared （UV-vis-NIR） spectrophotometer. Therefore, it is hopeful that the fl-Ga203 film can be used in the UV optoelectronic devices.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China （Nos. 21233001, 21129001, 51272006, 51432002, and 51121091）, the National Basic Research Program of China （No. 2011CB932601） and Beijing Municipal Science and Technology Commission （No. D141100000614001）.
文摘A scalable approach to obtaining high-density, large-area single-walled carbon nanotube （SWNT） arrays is essential for realizing the full potential of SWNTs in practical electronic devices; this is still a great challenge. Here, we report an improved synthetic method for large-area growth of ultra-high-density SWNT arrays on sapphire surfaces by combining Trojan catalysts （released from the substrate, to assure ultra-high density） with Mo nanoparticles （loaded on the surface, to stabilize the released Trojan catalysts） as cooperating catalysts. Dense and perfectly aligned SWNTs covered the entire substrate and the local density was as high as 160 tubes/pro. Field-effect transistors （FETs） built on such arrays gave an output current density of -488 μA/μm at the drain-source voltage （Vds） = the gate-source voltage （Vgs） = -2 V, corresponding to an on-conductance per width of 244 μS/μm. These results confirm the wide range of potential applications of Trojan-Mo catalysts in the structure-controlled growth of SWNTs.
基金supported by the National Natural Science Foundation of China(91833301 and 61427901)Guangdong Natural Science Funds for Distinguished Young Scholars(2021B1515020105)Guangdong Basic and Applied Basic Research Foundation(2019A1515110916)。
文摘One judiciously designed strategy of utilizing an ultrathin but conductive Ga_(2)O_(3):Si nanolayer to prepare(AlGa)_(2)O_(3)crystalline film is demonstrated.Benefiting from the existence of Ga_(2)O_(3):Si nanolayer,a high-quality(Al_(0.68)Ga_(0.32))_(2)O_(3)sesquioxide film with 68 at.%aluminum was epitaxially grown on sapphire substrates,which was characterized by high-resolution transmission electron microscopy,X-ray photoelectron spectroscopy and X-ray diffraction.Its bandgap was broadened to 6.14 eV,and a vacuum ultraviolet(VUV)(AlGa)_(2)O_(3)/Ga_(2)O_(3):Si photodetector was subsequently fabricated.The detector exhibits a pretty high on-off ratio of about 10^(3),an open-circuit voltage of 1.0 V and a responsivity of 8.1 mA W^(-1) at 0 V bias voltage.The performances imply that the proposed strategy is valuable for improving the quality and also adjusting the bandgap of(AlGa)_(2)O_(3)sesquioxides,which is expected to facilitate their application in VUV photodetection.
文摘Compared to traditional optical domes, domes of sapphire coated with films can effectively reduce emissivity and increase transmittance. The purpose of this work is to investigate the thermal radiation effect on sapphire optical dome coated with yttrium oxide by a radio frequency mag- netron sputtering method. The emissivity of sapphire coated with Y203 films is studied by both numerical and experi- mental methods. The results indicate that the emissivity of sapphire substrate is reduced effectively with increasing the thickness of the Y203 film. In addition, a finite element model is developed to simulate the radiation intensity of the optical dome. The thermal responses indicate that the max- imum temperature is reduced apparently compared with the uncoated sapphire as Y203 film thicknesses increase. The average irradiance distribution at different film thicknesses with time shows that the self-thermal radiation disturbance of sapphire optical dome delays 0.93 s when the thickness of Y203 film is 200μm, which can guarantee the dome works properly and effectively even in a harsh environment.
基金supported by National Natural Science Foundation of China (GrantNos. 40772197,40972232)National High-Tech Research & Development (Grant No. 2006BAB01A03)National Support Program of Science & Technology (Grant Nos. 2006BAB01A01,2006BAB01A03)
文摘The Baoshan Block is tectonically located in the middle segment of the Sibumasu plate. Granitic magmatism within the Baoshan Block has been considered weakly active due mainly to very limited exposures during the Himalaya orogenic episode. The geochronological study on the buried Shuangmaidi granite has confirmed the existence of the Cenozoic granitoids in the Baoshan Block. The present study indicates that： （1） It is medium- to coarse-grained two mica phyric granite, characterized by high SiO2 （73.55%-77.16%） and low CaO （0.34%-1.38%） contents, with a total alkalis （K2O＋Na2O） of 5.22%-8.03%, K2O/Na2O ratios of 0.24-1.79, and total rare earth elements （ZREE） of the granite between 85 and 125 ppb. All samples are enriched in light REE and exhibit medium negative Eu anomalies; and they show pronounced negative anomalies in Ba, Sr, Ti, and Nb but significant positive anomalies in K, Rb, U, Th, and Pb on mantle-normalized trace element patterns, indicating typi-cally peraluminous to strongly peraluminous S-type granite. （2） The zircon SHRIMP U-Pb ages of the granite are 36.27±0.48 Ma for the samples from ZK7-1 and 35.78±0.49 Ma for those from ZK0-1, respectively. The similar zircon ages from these two drill cores may suggest that the granite samples come from the same buried pluton. （3） 206pb/204pb values of the granite vary from 20.115 to 25.359, 207pb/204pb from 15.776 to 16.160, and 208pb/204pb from 39.236 to 41.285, showing the characteristics of radio- active lead anomaly of the upper crust. The （87Sr/86Sr）i values calculated on the average age of the two-mica orthoclase granite （36 Ma） range from 0.72524 to 0.77503 and eNd（t） values vary from -10.9 to -11.7. These data, along with the depleted-mantle Nd modal ages of 1.73-1.80 Ga, imply that the granites might have formed from partial melting of the Precambrian crystal basements. （4） On the Hf-Rb-Ta diagram, almost all the samples fall within the field of post-collision tectonic setting. The CaO/Na2O and A1203/TiO2 ratios suggest that the granitic magma may have formed from partial melting of clay-rich crustal materials with a pos- sible melting temperature of about 900℃ and a possible crystallization temperature of 775-795~C. （5） During the post-collision of the Himalaya orogen, with the southeastward extrusion of the Indochina continent resulting from the continuous northward indentation of the India continent into the Asia, the Gaoligong Fault, as the western boundary of the Indochina continent, moved in the dextral strike-slip on a large scale to trigger partial melting of the thickened crust, and the peraluminous granitic magma from which the Shuangmaidi two-mica orthoclase granite derived was formed.
基金supported by the National Natural Science Foundation of China (Grant Nos. 60890192 and 50872146)
文摘Nonpolar a-plane （1120） GaN films have been grown on r-plane （1102） sapphire by metal-organic chemical vapor deposition （MOCVD） under different growth pressures. The as-grown films are investigated by optical microscopy, high-resolution X-ray diffraction （HRXRD） and Raman scattering. As growth pressure rises from 100 mbar to 400 mbar, the surface gets rougher, and the in-plane XRD full width at half maximum （FWHM） along the c-axis [0001] increases while that along the m-axis [1100] decreases. Meanwhile, residential stresses are reduced along both the c-axis and the m-axis. The structural anisotropy feature under 400 mbar is inverted with respect to 100 mbar, and the weakened anisotropy is achieved under a moderate pressure of 200 mbar, probably due to the suppressed Ga atomic migration along the c-axis under a larger pressure. We propose that pressure can affect a-plane growth through the V/III ratio.
