To elaborate soil moisture and grain size characteristics of 3 typical micro-areas in Minqin oasis-desert ecotone,samples were collected in runoff generation area and accumulated area using soil profile and multi-poin...To elaborate soil moisture and grain size characteristics of 3 typical micro-areas in Minqin oasis-desert ecotone,samples were collected in runoff generation area and accumulated area using soil profile and multi-point sampling method,for soil moisture and physicochemical property analysis. Research results that( i) water accumulation trace of accumulated area is significant and the vegetation coverage is larger than the runoff generation area. The crust development in clay sand barrier + Haloxylon ammodendron forest accumulated is better than runoff generation area,while the situation is contrary in Nitraria tangutorum sand dune lowland and clay flat land.( ii) Moisture of accumulated area in fixed Nitraria tangutorum sand inter-dune lowland is better than the runoff generation area; the moisture of accumulated area in clay flat land topsoil is significantly better than the runoff generation area,while the topsoil moisture of clay sand barrier + Haloxylon ammodendron forest is better in the runoff generation area than in the accumulated area.( iii) Soil moisture of accumulated area in 3 types of micro-areas is in the range of 20- 40 cm; the fixed Nitraria tangutorum sand inter-dune lowland is better than clay flat land and clay sand barrier + Haloxylon ammodendron forest,while the lowest moisture of corresponding runoff generation area is basically consistent with the depth.( iv) The topsoil clay and powder content in accumulated area of fixed Nitraria tangutorum sand inter-dune lowland is lower than the runoff generation area,while the fine sand content in deep layer of runoff generation area is greater than the accumulated area; soil in two areas of clay flat land mainly consists of coarse and fine sand,and clay particles are better in runoff generation area than in accumulated area. Soil in the clay sand barrier + Haloxylon ammodendron forest is mainly coarse sand and the structure is single. In sum,through adjusting allocation of rainfall,micro-areas influence soil moisture and grain size distribution,and further influence spatial- temporal distribution of vegetation in sand micro-areas.展开更多
Antimicrobial material is highly desired because of the increasing demand in biomedical application to prevent from the formation of biofilm.A common strategy for enhancing the antibacterial property of a metal materi...Antimicrobial material is highly desired because of the increasing demand in biomedical application to prevent from the formation of biofilm.A common strategy for enhancing the antibacterial property of a metal material is to incorporate toxic metal such as Cu and Ag.However,the reported Cu^(2+)or Ag~+released concentration from antibacterial alloys was much less than the reported minimum inhibitory ion concentrations(MIC),revealing the existence of an unknown alternative antimicrobial mechanism not relying on the toxicity of the metal ions.Herein,we proposed a new antibacterial mechanism that the antibacterial effectiveness of the different alloys is proportional to the micro-area potential differences(MAPDs)on the surface of the alloys.We designed three kinds of Ti-M(M=Zr,Ta and Au)alloys to eliminate the potential antibacterial contribution from Cu and Ag ion.We demonstrated that high MAPDs are associated with great production of reactive oxygen species(ROS),resulting in the killing effect to the biofilm known to be associated with implant infections(Staphlococcus aureus and Escherichia coli).These results provide new insights for the design of antibacterial alloys.展开更多
This in vitrostudy aims to evaluate the crystal and surface microstructure of dental enamel after cold-light bleaching treatment. Twelve sound human premolars were cross-split into four specimens, namely, mesio-buccal...This in vitrostudy aims to evaluate the crystal and surface microstructure of dental enamel after cold-light bleaching treatment. Twelve sound human premolars were cross-split into four specimens, namely, mesio-buccal （Group LP）, disto-buccal （Group P）, mesio-lingual （Group NP） and disto-lingual （Group L） specimens. These four groups were treated using the standard cold-light bleaching procedure, a bleaching agent, a peroxide-free bleaching agent and cold-light, respectively. Before and after treatment, all specimens were analyzed by high-resolution, micro-area X-ray diffraction and scanning electron microscopy. Using a spectrometer, tooth color of all specimens was measured before and after treatment. The phase of the enamel crystals was identified as hydroxyapatite and carbonated hydroxyapatite. After treatment, specimens in Groups LP and P showed significantly weaker X-ray diffraction peaks, significant reduction in crystal size and crystallinity, significant increase in L~ but decrease in a＊ and b＊, and obvious alterations in the surface morphology. However, specimens in Groups NP and L did not show any significant changes. The cold-light bleaching treatment leads to demineralization in the enamel surface. The acidic peroxide-containing bleaching agent was the major cause of demineralization, whereas cold-light did not exhibit significant increase or decrease effect on this demineralization.展开更多
Rapid analysis of metal ions and organic compounds in strong acidic solutions is of sustainable interest in multiple disciplines.However,complicated and time-consuming pretreatments are always required for MS analysis...Rapid analysis of metal ions and organic compounds in strong acidic solutions is of sustainable interest in multiple disciplines.However,complicated and time-consuming pretreatments are always required for MS analysis of the compounds in strong acidic solutions.Otherwise,it will result in a weak signal and cause serious damage to the mass spectrometer.Herein,a simple method inherited from nano-ESI MS was developed for rapid analysis of strong acidic solutions.Nanoliter(nL)strong acidic solution was first loaded in the nano-ESI emitter,followed by evaporation to remove the H+and leave the analytes on the wall of the nano-ESI emitter.The evaporation process can be completed within 1 min because of the extremely tiny volume(≤1 nL)of the loaded solution.Then,the dried analytes on the wall of the nano-ESI emitter were redissolved by loading a new solvent,followed by nano-ESI MS analysis.By using this method,metal ions and organic compounds in the strong acidic solution can be detected with low sample consumption(1 nL),high speed(<2 min/sample),high sensitivity(limit of detection=0.2µg/L),and high accuracy(>90%).Proof-of-concept applications of the present method have been successfully achieved for the analysis of gastric juice(pH of the sample=1),monitoring reaction catalyzed by strong acid(pH of the system=0),and micro-area analysis of ores(pH of the extraction solvent=0),showing great application potential in multiple fields.展开更多
With the help of high-energy mechanical milling and a-SiO2 as the initial material, we investigated the synthesis of coesite at a high temperature and high pressure under the condition of adding a certain amount of ha...With the help of high-energy mechanical milling and a-SiO2 as the initial material, we investigated the synthesis of coesite at a high temperature and high pressure under the condition of adding a certain amount of hard Fe filling. The synthetic samples were measured by XRD and Raman spectroscopy. The results show that a small amount of small-sized coesite can be obtained under 2.5 GPa and 973 K.展开更多
The Epiphyton occurred in the carbonate rock of lower Paleozoic in North China was analyzed by using the optical and some micro-area methods such as Micro-FT-IR and TOF-SIMS. The result shows that tbe Epiphyton belong...The Epiphyton occurred in the carbonate rock of lower Paleozoic in North China was analyzed by using the optical and some micro-area methods such as Micro-FT-IR and TOF-SIMS. The result shows that tbe Epiphyton belonging to the calcic algae has a certain hydrocarbon-generating potential and the hydrocarbou-generating action may continue to the high mature stage.展开更多
The basic granulite, which is considered to be the MORB based on geochemistry and isotopic characteristics[1], has been discovered recently as the enclaves in the Yingjiang island-arc magmatic suite on the border of B...The basic granulite, which is considered to be the MORB based on geochemistry and isotopic characteristics[1], has been discovered recently as the enclaves in the Yingjiang island-arc magmatic suite on the border of Burma and west Yunnan, east of Myitkyina suture in the eastern Burma. The laser micro-area 40Ar-39Ar technique is used to date the age of garnet展开更多
基金Supported by Project of National Natural Science Foundation(41161006)State Key Development Program of Basic Research of China(2012CB723203)+1 种基金National Key Technology Research and Development Program of the Ministry of Science and Technology of China(2012BAD16B0203)Project for Scientific and Technological Innovation Team of Protection and Use of Psammophytes in Gansu Province(1207TTCA002)
文摘To elaborate soil moisture and grain size characteristics of 3 typical micro-areas in Minqin oasis-desert ecotone,samples were collected in runoff generation area and accumulated area using soil profile and multi-point sampling method,for soil moisture and physicochemical property analysis. Research results that( i) water accumulation trace of accumulated area is significant and the vegetation coverage is larger than the runoff generation area. The crust development in clay sand barrier + Haloxylon ammodendron forest accumulated is better than runoff generation area,while the situation is contrary in Nitraria tangutorum sand dune lowland and clay flat land.( ii) Moisture of accumulated area in fixed Nitraria tangutorum sand inter-dune lowland is better than the runoff generation area; the moisture of accumulated area in clay flat land topsoil is significantly better than the runoff generation area,while the topsoil moisture of clay sand barrier + Haloxylon ammodendron forest is better in the runoff generation area than in the accumulated area.( iii) Soil moisture of accumulated area in 3 types of micro-areas is in the range of 20- 40 cm; the fixed Nitraria tangutorum sand inter-dune lowland is better than clay flat land and clay sand barrier + Haloxylon ammodendron forest,while the lowest moisture of corresponding runoff generation area is basically consistent with the depth.( iv) The topsoil clay and powder content in accumulated area of fixed Nitraria tangutorum sand inter-dune lowland is lower than the runoff generation area,while the fine sand content in deep layer of runoff generation area is greater than the accumulated area; soil in two areas of clay flat land mainly consists of coarse and fine sand,and clay particles are better in runoff generation area than in accumulated area. Soil in the clay sand barrier + Haloxylon ammodendron forest is mainly coarse sand and the structure is single. In sum,through adjusting allocation of rainfall,micro-areas influence soil moisture and grain size distribution,and further influence spatial- temporal distribution of vegetation in sand micro-areas.
基金the financial support from National Natural Science Foundation of China(Nos.81071262/H1820 and 31971253/C1002)the instrumental analysis from Analytical and Testing Center,Northeastern University。
文摘Antimicrobial material is highly desired because of the increasing demand in biomedical application to prevent from the formation of biofilm.A common strategy for enhancing the antibacterial property of a metal material is to incorporate toxic metal such as Cu and Ag.However,the reported Cu^(2+)or Ag~+released concentration from antibacterial alloys was much less than the reported minimum inhibitory ion concentrations(MIC),revealing the existence of an unknown alternative antimicrobial mechanism not relying on the toxicity of the metal ions.Herein,we proposed a new antibacterial mechanism that the antibacterial effectiveness of the different alloys is proportional to the micro-area potential differences(MAPDs)on the surface of the alloys.We designed three kinds of Ti-M(M=Zr,Ta and Au)alloys to eliminate the potential antibacterial contribution from Cu and Ag ion.We demonstrated that high MAPDs are associated with great production of reactive oxygen species(ROS),resulting in the killing effect to the biofilm known to be associated with implant infections(Staphlococcus aureus and Escherichia coli).These results provide new insights for the design of antibacterial alloys.
文摘This in vitrostudy aims to evaluate the crystal and surface microstructure of dental enamel after cold-light bleaching treatment. Twelve sound human premolars were cross-split into four specimens, namely, mesio-buccal （Group LP）, disto-buccal （Group P）, mesio-lingual （Group NP） and disto-lingual （Group L） specimens. These four groups were treated using the standard cold-light bleaching procedure, a bleaching agent, a peroxide-free bleaching agent and cold-light, respectively. Before and after treatment, all specimens were analyzed by high-resolution, micro-area X-ray diffraction and scanning electron microscopy. Using a spectrometer, tooth color of all specimens was measured before and after treatment. The phase of the enamel crystals was identified as hydroxyapatite and carbonated hydroxyapatite. After treatment, specimens in Groups LP and P showed significantly weaker X-ray diffraction peaks, significant reduction in crystal size and crystallinity, significant increase in L~ but decrease in a＊ and b＊, and obvious alterations in the surface morphology. However, specimens in Groups NP and L did not show any significant changes. The cold-light bleaching treatment leads to demineralization in the enamel surface. The acidic peroxide-containing bleaching agent was the major cause of demineralization, whereas cold-light did not exhibit significant increase or decrease effect on this demineralization.
基金supported by the National Natural Science Foundation of China(Nos.21864001,21727812 and 21765001)the Ph.D.Start-up Foundation of East China University of Technology(No.DHBK2020001).
文摘Rapid analysis of metal ions and organic compounds in strong acidic solutions is of sustainable interest in multiple disciplines.However,complicated and time-consuming pretreatments are always required for MS analysis of the compounds in strong acidic solutions.Otherwise,it will result in a weak signal and cause serious damage to the mass spectrometer.Herein,a simple method inherited from nano-ESI MS was developed for rapid analysis of strong acidic solutions.Nanoliter(nL)strong acidic solution was first loaded in the nano-ESI emitter,followed by evaporation to remove the H+and leave the analytes on the wall of the nano-ESI emitter.The evaporation process can be completed within 1 min because of the extremely tiny volume(≤1 nL)of the loaded solution.Then,the dried analytes on the wall of the nano-ESI emitter were redissolved by loading a new solvent,followed by nano-ESI MS analysis.By using this method,metal ions and organic compounds in the strong acidic solution can be detected with low sample consumption(1 nL),high speed(<2 min/sample),high sensitivity(limit of detection=0.2µg/L),and high accuracy(>90%).Proof-of-concept applications of the present method have been successfully achieved for the analysis of gastric juice(pH of the sample=1),monitoring reaction catalyzed by strong acid(pH of the system=0),and micro-area analysis of ores(pH of the extraction solvent=0),showing great application potential in multiple fields.
基金Supported by the National Natural Science Foundation of China(Nos.50872041 and 10674034)the National Foundation for Fostering Talent in Basic Science of China(No.J0730311)the Foundation of State Key Laboratory of Superhand Mate-rials(No.200908)
文摘With the help of high-energy mechanical milling and a-SiO2 as the initial material, we investigated the synthesis of coesite at a high temperature and high pressure under the condition of adding a certain amount of hard Fe filling. The synthetic samples were measured by XRD and Raman spectroscopy. The results show that a small amount of small-sized coesite can be obtained under 2.5 GPa and 973 K.
文摘The Epiphyton occurred in the carbonate rock of lower Paleozoic in North China was analyzed by using the optical and some micro-area methods such as Micro-FT-IR and TOF-SIMS. The result shows that tbe Epiphyton belonging to the calcic algae has a certain hydrocarbon-generating potential and the hydrocarbou-generating action may continue to the high mature stage.
文摘The basic granulite, which is considered to be the MORB based on geochemistry and isotopic characteristics[1], has been discovered recently as the enclaves in the Yingjiang island-arc magmatic suite on the border of Burma and west Yunnan, east of Myitkyina suture in the eastern Burma. The laser micro-area 40Ar-39Ar technique is used to date the age of garnet
