This study assessed the effect of patch scarification and mounding on the physical properties of the root layer and the success of tree planting in various types of forests.This study was conducted on 12 forest sites ...This study assessed the effect of patch scarification and mounding on the physical properties of the root layer and the success of tree planting in various types of forests.This study was conducted on 12 forest sites in taiga forests of the European part of Russia.A total of 54 plots were set up to assess seedling survival;root collar diameter,height,and heigh increment were measured for 240 seedlings to assess growth.In the rooting layer,240 soil samples were taken to determine physical properties.The study showed that soil treatment methods had no effect on bulk density and total porosity in Cladina sites.However,reduced soil moisture was noted,particularly in mounds,resulting in increased aeration.In Myrtillus sites,there were increased bulk density,reduced soil moisture,and total porosity in the mounds.Mounding treatment in Polytrichum sites resulted in reduced soil moisture and increased aeration porosity.In the Myrtillus and Polytrichum sites,patch scarification had no effects on physical properties.In Polytrichum sites,survival rates,heights,and heigh increments of bareroot Norway spruce seedlings in mounds were higher than in patches;however,the same did not apply to diameter.In Cladina and Myrtillus sites,there was no difference in growth for bareroot and containerised seedlings with different soil treatments.Growing conditions and soil types should be considered when applying different soil treatment methods to ensure high survival rates and successful seedling growth.展开更多
We recently read the study by Kayano et al on intracorporeal anastomosis(IA)for colon cancer,which assessed bacterial contamination and medium-term onco-logical outcomes and affirmed that IA is analogous to extracorpo...We recently read the study by Kayano et al on intracorporeal anastomosis(IA)for colon cancer,which assessed bacterial contamination and medium-term onco-logical outcomes and affirmed that IA is analogous to extracorporeal anastomosis in reducing intraperitoneal bacterial risk and achieving similar oncological results.Our commentary addresses gaps,particularly concerning bowel preparation and surgical site infections(SSIs),and highlights the need for comprehensive details on the bowel preparation methods that are currently employed,including mecha-nical bowel preparation,oral antibiotics(OA),their combination,and specific OA types.We emphasize the necessity for further analyses that investigate these me-thods and their correlation with SSI rates,to enhance clinical protocol guidance and optimize surgical outcomes.Such meticulous analyses are essential for refi-ning strategies to effectively mitigate SSI risk in colorectal surgeries.展开更多
In this article,the characteristic of the field plastic mulch, the craft for mechanization removal and land preparation of plastic mulch and the mechanism frequently used in the removal and land preparation of plasti...In this article,the characteristic of the field plastic mulch, the craft for mechanization removal and land preparation of plastic mulch and the mechanism frequently used in the removal and land preparation of plastic mulch were introduced, which offered references for the design of removal mechanism and land preparation of plastic mulch and structural optimization combination of working components.展开更多
A new preparation method of the N-ethyl 7,17-seco C_(19)-diterpenoid alkaloids(5)and(6)by pyrolysis of the N-oxides(3)and(4),respectively, in anhydrous diglyme is described.A probable reaction mechanism for the pyroly...A new preparation method of the N-ethyl 7,17-seco C_(19)-diterpenoid alkaloids(5)and(6)by pyrolysis of the N-oxides(3)and(4),respectively, in anhydrous diglyme is described.A probable reaction mechanism for the pyroly- sis is presented and studied preliminarily.展开更多
The preparation methods of hollow polymer microspheres both at home and abroad are summarized, and their preparation mechanisms and developmental states are presented. These methods include the liquid droplet method, ...The preparation methods of hollow polymer microspheres both at home and abroad are summarized, and their preparation mechanisms and developmental states are presented. These methods include the liquid droplet method, dried-gel droplet method, self-assembly method, microencapsulation method, emulsion polymerization method and the template method. Hollow polystyrene microspheres are the most extensively studied in the research of hollow polymer microspheres. Through comparison of the advantages and disadvantages of different preparation methods, it is concluded that microencapsulation method is most suitable for preparing polystyrene hollow microspheres.展开更多
Rapidly solidified 2024 aluminium alloy powders were mechanically milled, then consolidated to bulk form. The microstructural changes of the powders in mechanical milling (MM) and consolidation process were characteri...Rapidly solidified 2024 aluminium alloy powders were mechanically milled, then consolidated to bulk form. The microstructural changes of the powders in mechanical milling (MM) and consolidation process were characterized by X-ray diffraction analyses and transmission electron microscopy observations. The results showed that mechanical milling reduced the grain size to nanometer, dissolved the Al2Cu intermetallic compound into the aluminium matrix and produced an aluminium supersaturated solid solution. During consolidation process. the grain size increased to submicrometer, and the Al2Cu and Al2(Cu, Mg, Si, Fe, Mn) compounds precipitated owing to heating. Increasing consolidation temperature and time results in obvious grain growth and coarsening of second phase particles. The tensile yield strength of the consolidated alloy with submicrometer size grains increases with decreasing grain size, and it follows the famous HallPetch relation展开更多
The structure and magnetic properties of SmyFe100-1.5yC0.5y(y=8~20) alloys prepared by mechanical alloying (MA) from Sm, Fe and graphite have been investigated systematically. In order to improve hard magnetic proper...The structure and magnetic properties of SmyFe100-1.5yC0.5y(y=8~20) alloys prepared by mechanical alloying (MA) from Sm, Fe and graphite have been investigated systematically. In order to improve hard magnetic properties of the alloys prepared by mechanical alloying, a new method consisting of re-milling and re-annealing was developed. After being re-milled and re-annealed, the Curie temperature TC of the Sm-Fe-C alloys changes. The TC of 2:17 phase increases, whereas the TC of 2:14:1 phase decreases. After being re-annealed at low temperatures, the grain sizes of hard phases are smaller than those in the alloys annealed at high temperatures. The effects of Co or Ti substitution for Fe are studied.展开更多
The pattern evolution and dynamic mechanism of the dynamic changes of regional gravity fields occurring before and after the Wenchuan Ms8.0 earthquake are analyzed, based on five epochs of 1998 -2007 mobile gravity da...The pattern evolution and dynamic mechanism of the dynamic changes of regional gravity fields occurring before and after the Wenchuan Ms8.0 earthquake are analyzed, based on five epochs of 1998 -2007 mobile gravity data from the middle-south section of the north-south seismic belt, and two epochs of field research data collected after the 2008 Wenchuan earthquake in combination with GPS data, leveling observations, and geotectonic environment data. The regional dynamic gravity changes demonstrate the effects of the eastward flow of solid matter in the Qinghai-Tibetan plateau and the preparation of the 2008 Wenchuan earthquake (2- 10 yr). The two most meaningful gravity indicators of the Wcnchuan earthquake preparation are the positive (increasing) gravity changes occurring over many years in the southwest epicenter and the largescale gradient zone of gravity variation, with the cumulative difference between the two sides of the gradient zone of gravity exceeding 200 μGal. The positive gravity changes may facilitate a constant energy accumulation and the gradient belt may support seismic shear breakage. Overall, the gravity changes associated with the earthquake preparation indicate a pattern of accelerating increase-decelerating increase-earthquake occurrence. The Songpan-Ganzi block generally displays a negative gravity change, providing evidence for a local upwarp- ing of the deep crust-mantle and an interior expansion of the deep crust attributable to high temperatures. The viewpoint is consistent with the dilatant mechanism for earthquake preparation.展开更多
Copper antimony selenium(CuSbSe_(2))has advantages of adjustable band gaps from 1.09 eV to 1.2 eV,high light absorption coefficient(>105 cm-1),and low grain generation temperature(300—400℃),which is suitable for ...Copper antimony selenium(CuSbSe_(2))has advantages of adjustable band gaps from 1.09 eV to 1.2 eV,high light absorption coefficient(>105 cm-1),and low grain generation temperature(300—400℃),which is suitable for the preparation of solar cells.However,the stable range of CuSbSe_(2)(CASe)phase is narrow,which is inevitable to form Sb_(2)Se_(3)and Cu_(3)SbSe_(4)second phase during the preparation process.In this work,selenization annealing of Sb/Cu metal layer to prepare CASe thin films with pulse electrodeposition process was studied,and the growth mechanism of CASe film was analyzed.Cu and Sb reacted with Se to form Cu_(2)Se and Sb_(2)Se_(3),respectively.Then Cu_(2)Se and Sb_(2)Se_(3)further reacted to generate CASe.Since the formation temperature of Cu_(3)SbSe_(4)was lower than that of CASe,the preferential formation of Cu_(3)SbSe_(4)led to layer separation.When the annealing temperature was too high,CASe decomposed to form Cu_(3)SbSe_(3)and Sb_(2)Se_(3).Additionally,by increasing the heating rate,the separation of CASe thin films was effectively improved,and the CASe thin films with relatively high crystallinity were obtained at 360℃with heating rate of 30℃/min and selenization time of 20 min.展开更多
Intermetallic compounds have the characteristics of long-range ordered structure and combination of metallic and covalent bonds,showing intrinsic brittleness and outstanding performance stability.The synthesis mechani...Intermetallic compounds have the characteristics of long-range ordered structure and combination of metallic and covalent bonds,showing intrinsic brittleness and outstanding performance stability.The synthesis mechanism,pore structure characterization and material properties of powder metallurgy porous intermetallics are reviewed in this paper.Compared with traditional porous materials,porous intermetallics have good thermal impact resistance,machinability,thermal and electrical conductivity similar to metals,as well as good chemical corrosion resistance,rigidity and high-temperature property similar to ceramics.The mechanisms of preparation and pore formation of porous intermetallics mainly include four aspects:(1)the physical process based on the interstitial space between the initial particles and its evolution in the subsequent procedures;(2)the chemical combustion process based on the violent reaction between the initial powder components;(3)the reaction kinetics process based on the difference between the diffusion rates of elements;(4)the phase transition process based on the difference between the phase densities.The characterization parameters to the pore structure description for porous intermetallics include mainly overall porosity,open porosity,permeability,maximum pore size,pore size distribution and tortuosity factor.In terms of microstructure characterization of porous intermetallics,three-dimensional pore morphology scanning technology has the potential to reveal the internal characteristics of pore structures.The research on material properties of porous intermetallics mainly focuses on electrochemical catalytic activity,generalized oxidation resistivity at high temperature,resistance against chemical corrosion and mechanical properties,which have obvious advantages over traditional porous materials.In the field of the development of porous intermetallics,it is expected to expand their applications by further reducing the pore size to the nanoscale level to improve the filtration accuracy or increase the specific surface area,as well as introducing the high entropy design on the composition to improve the brittleness and enhance their material performance.展开更多
TiO2 nanomaterial is promising with its high potential and outstanding performance in photocatalytic environmental applications, such as CO2 conversion, water treatment, and air quality control. For many of these appl...TiO2 nanomaterial is promising with its high potential and outstanding performance in photocatalytic environmental applications, such as CO2 conversion, water treatment, and air quality control. For many of these applications, the particle size, crystal structure and phase, porosity, and surface area influence the activity of TiO2 dramatically. TiO2 nanomaterials with special structures and morphologies, such as nanospheres, nanowires, nanotubes, nanorods, and nanoflowers are thus synthesized due to their desired characteristics. With an emphasis on the different morphologies of TiO2 and the influence factors in the synthesis, this review summarizes fourteen TiO2 preparation methods, such as the sol-gel method, solvothermal method, and reverse micelle method. The TiO2 formation mechanisms, the advantages and disadvantages of the preparation methods, and the photocatalytic environmental application examples are proposed as well.展开更多
A non-precious metal catalyst CoMe]C for the oxygen reduction reaction is prepared by heat-treating a mechanical mixture of carbon black, melamine and cobalt chloride at 600 under nitrogen atmosphere for 2 h. The cata...A non-precious metal catalyst CoMe]C for the oxygen reduction reaction is prepared by heat-treating a mechanical mixture of carbon black, melamine and cobalt chloride at 600 under nitrogen atmosphere for 2 h. The catalytic activity of CoMe/C is characterized by the electrochemical linear sweep voltammetry technique. The onset reduction potential of the catalyst is 0.55 V (vs. SCE) at a scanning rate of 5 mV/s in 0.5 mol/L H2SO4 solution. The formation of the ORR activity sites of CoMe/C is facilitated by metallic β- cobalt.展开更多
基金based on studies conducted under a governmental request to“Northern Research Institute of Forestry”for performance of applied research within the remit of the Federal Forestry Agency.Project registration No.122020100319-9。
文摘This study assessed the effect of patch scarification and mounding on the physical properties of the root layer and the success of tree planting in various types of forests.This study was conducted on 12 forest sites in taiga forests of the European part of Russia.A total of 54 plots were set up to assess seedling survival;root collar diameter,height,and heigh increment were measured for 240 seedlings to assess growth.In the rooting layer,240 soil samples were taken to determine physical properties.The study showed that soil treatment methods had no effect on bulk density and total porosity in Cladina sites.However,reduced soil moisture was noted,particularly in mounds,resulting in increased aeration.In Myrtillus sites,there were increased bulk density,reduced soil moisture,and total porosity in the mounds.Mounding treatment in Polytrichum sites resulted in reduced soil moisture and increased aeration porosity.In the Myrtillus and Polytrichum sites,patch scarification had no effects on physical properties.In Polytrichum sites,survival rates,heights,and heigh increments of bareroot Norway spruce seedlings in mounds were higher than in patches;however,the same did not apply to diameter.In Cladina and Myrtillus sites,there was no difference in growth for bareroot and containerised seedlings with different soil treatments.Growing conditions and soil types should be considered when applying different soil treatment methods to ensure high survival rates and successful seedling growth.
文摘We recently read the study by Kayano et al on intracorporeal anastomosis(IA)for colon cancer,which assessed bacterial contamination and medium-term onco-logical outcomes and affirmed that IA is analogous to extracorporeal anastomosis in reducing intraperitoneal bacterial risk and achieving similar oncological results.Our commentary addresses gaps,particularly concerning bowel preparation and surgical site infections(SSIs),and highlights the need for comprehensive details on the bowel preparation methods that are currently employed,including mecha-nical bowel preparation,oral antibiotics(OA),their combination,and specific OA types.We emphasize the necessity for further analyses that investigate these me-thods and their correlation with SSI rates,to enhance clinical protocol guidance and optimize surgical outcomes.Such meticulous analyses are essential for refi-ning strategies to effectively mitigate SSI risk in colorectal surgeries.
基金Supported by Heilongjiang Province "Tenth Five-Year Plan"the Key Tackling Item (GC01B708)
文摘In this article,the characteristic of the field plastic mulch, the craft for mechanization removal and land preparation of plastic mulch and the mechanism frequently used in the removal and land preparation of plastic mulch were introduced, which offered references for the design of removal mechanism and land preparation of plastic mulch and structural optimization combination of working components.
文摘A new preparation method of the N-ethyl 7,17-seco C_(19)-diterpenoid alkaloids(5)and(6)by pyrolysis of the N-oxides(3)and(4),respectively, in anhydrous diglyme is described.A probable reaction mechanism for the pyroly- sis is presented and studied preliminarily.
文摘The preparation methods of hollow polymer microspheres both at home and abroad are summarized, and their preparation mechanisms and developmental states are presented. These methods include the liquid droplet method, dried-gel droplet method, self-assembly method, microencapsulation method, emulsion polymerization method and the template method. Hollow polystyrene microspheres are the most extensively studied in the research of hollow polymer microspheres. Through comparison of the advantages and disadvantages of different preparation methods, it is concluded that microencapsulation method is most suitable for preparing polystyrene hollow microspheres.
文摘Rapidly solidified 2024 aluminium alloy powders were mechanically milled, then consolidated to bulk form. The microstructural changes of the powders in mechanical milling (MM) and consolidation process were characterized by X-ray diffraction analyses and transmission electron microscopy observations. The results showed that mechanical milling reduced the grain size to nanometer, dissolved the Al2Cu intermetallic compound into the aluminium matrix and produced an aluminium supersaturated solid solution. During consolidation process. the grain size increased to submicrometer, and the Al2Cu and Al2(Cu, Mg, Si, Fe, Mn) compounds precipitated owing to heating. Increasing consolidation temperature and time results in obvious grain growth and coarsening of second phase particles. The tensile yield strength of the consolidated alloy with submicrometer size grains increases with decreasing grain size, and it follows the famous HallPetch relation
基金National Natural Science FOundation of China! 59725103National Natural Science FOundation of China! 59831010Sciences and
文摘The structure and magnetic properties of SmyFe100-1.5yC0.5y(y=8~20) alloys prepared by mechanical alloying (MA) from Sm, Fe and graphite have been investigated systematically. In order to improve hard magnetic properties of the alloys prepared by mechanical alloying, a new method consisting of re-milling and re-annealing was developed. After being re-milled and re-annealed, the Curie temperature TC of the Sm-Fe-C alloys changes. The TC of 2:17 phase increases, whereas the TC of 2:14:1 phase decreases. After being re-annealed at low temperatures, the grain sizes of hard phases are smaller than those in the alloys annealed at high temperatures. The effects of Co or Ti substitution for Fe are studied.
基金financially supported by the National Natural Science Foundation of China (40574012,40374031)Key Project of the National Science & Technology Pillar Program in the Eleventh Five-year Plan(2006BAC01B02-02)Monitoring Project of China Earthquake Administration (201210)
文摘The pattern evolution and dynamic mechanism of the dynamic changes of regional gravity fields occurring before and after the Wenchuan Ms8.0 earthquake are analyzed, based on five epochs of 1998 -2007 mobile gravity data from the middle-south section of the north-south seismic belt, and two epochs of field research data collected after the 2008 Wenchuan earthquake in combination with GPS data, leveling observations, and geotectonic environment data. The regional dynamic gravity changes demonstrate the effects of the eastward flow of solid matter in the Qinghai-Tibetan plateau and the preparation of the 2008 Wenchuan earthquake (2- 10 yr). The two most meaningful gravity indicators of the Wcnchuan earthquake preparation are the positive (increasing) gravity changes occurring over many years in the southwest epicenter and the largescale gradient zone of gravity variation, with the cumulative difference between the two sides of the gradient zone of gravity exceeding 200 μGal. The positive gravity changes may facilitate a constant energy accumulation and the gradient belt may support seismic shear breakage. Overall, the gravity changes associated with the earthquake preparation indicate a pattern of accelerating increase-decelerating increase-earthquake occurrence. The Songpan-Ganzi block generally displays a negative gravity change, providing evidence for a local upwarp- ing of the deep crust-mantle and an interior expansion of the deep crust attributable to high temperatures. The viewpoint is consistent with the dilatant mechanism for earthquake preparation.
基金the National Natural Science Foundation of China(Nos.61804108 and 62074084)。
文摘Copper antimony selenium(CuSbSe_(2))has advantages of adjustable band gaps from 1.09 eV to 1.2 eV,high light absorption coefficient(>105 cm-1),and low grain generation temperature(300—400℃),which is suitable for the preparation of solar cells.However,the stable range of CuSbSe_(2)(CASe)phase is narrow,which is inevitable to form Sb_(2)Se_(3)and Cu_(3)SbSe_(4)second phase during the preparation process.In this work,selenization annealing of Sb/Cu metal layer to prepare CASe thin films with pulse electrodeposition process was studied,and the growth mechanism of CASe film was analyzed.Cu and Sb reacted with Se to form Cu_(2)Se and Sb_(2)Se_(3),respectively.Then Cu_(2)Se and Sb_(2)Se_(3)further reacted to generate CASe.Since the formation temperature of Cu_(3)SbSe_(4)was lower than that of CASe,the preferential formation of Cu_(3)SbSe_(4)led to layer separation.When the annealing temperature was too high,CASe decomposed to form Cu_(3)SbSe_(3)and Sb_(2)Se_(3).Additionally,by increasing the heating rate,the separation of CASe thin films was effectively improved,and the CASe thin films with relatively high crystallinity were obtained at 360℃with heating rate of 30℃/min and selenization time of 20 min.
基金the National Natural Science Foundation of China (No. 51971251, 51774336)。
文摘Intermetallic compounds have the characteristics of long-range ordered structure and combination of metallic and covalent bonds,showing intrinsic brittleness and outstanding performance stability.The synthesis mechanism,pore structure characterization and material properties of powder metallurgy porous intermetallics are reviewed in this paper.Compared with traditional porous materials,porous intermetallics have good thermal impact resistance,machinability,thermal and electrical conductivity similar to metals,as well as good chemical corrosion resistance,rigidity and high-temperature property similar to ceramics.The mechanisms of preparation and pore formation of porous intermetallics mainly include four aspects:(1)the physical process based on the interstitial space between the initial particles and its evolution in the subsequent procedures;(2)the chemical combustion process based on the violent reaction between the initial powder components;(3)the reaction kinetics process based on the difference between the diffusion rates of elements;(4)the phase transition process based on the difference between the phase densities.The characterization parameters to the pore structure description for porous intermetallics include mainly overall porosity,open porosity,permeability,maximum pore size,pore size distribution and tortuosity factor.In terms of microstructure characterization of porous intermetallics,three-dimensional pore morphology scanning technology has the potential to reveal the internal characteristics of pore structures.The research on material properties of porous intermetallics mainly focuses on electrochemical catalytic activity,generalized oxidation resistivity at high temperature,resistance against chemical corrosion and mechanical properties,which have obvious advantages over traditional porous materials.In the field of the development of porous intermetallics,it is expected to expand their applications by further reducing the pore size to the nanoscale level to improve the filtration accuracy or increase the specific surface area,as well as introducing the high entropy design on the composition to improve the brittleness and enhance their material performance.
基金the supports from the Clean Coal ProgramSchool of Energy Resources in Wyoming
文摘TiO2 nanomaterial is promising with its high potential and outstanding performance in photocatalytic environmental applications, such as CO2 conversion, water treatment, and air quality control. For many of these applications, the particle size, crystal structure and phase, porosity, and surface area influence the activity of TiO2 dramatically. TiO2 nanomaterials with special structures and morphologies, such as nanospheres, nanowires, nanotubes, nanorods, and nanoflowers are thus synthesized due to their desired characteristics. With an emphasis on the different morphologies of TiO2 and the influence factors in the synthesis, this review summarizes fourteen TiO2 preparation methods, such as the sol-gel method, solvothermal method, and reverse micelle method. The TiO2 formation mechanisms, the advantages and disadvantages of the preparation methods, and the photocatalytic environmental application examples are proposed as well.
基金supported by the Fundamental Research Funds for the Central Universities (No. CDJXS12220002)the Specialized Research Fund for the Doctoral Program of Sichuan University of Science and Engineering (No. 2012RC16)+2 种基金the Opening Project of Key Laboratory of Green Catalysis of Sichuan Institutes of High Education (No. LYJ1206)the National Undergraduate Innovation Training Project (No. 1110611046)Discipline Construction Project of Sichuan University of Science and Engineering
文摘A non-precious metal catalyst CoMe]C for the oxygen reduction reaction is prepared by heat-treating a mechanical mixture of carbon black, melamine and cobalt chloride at 600 under nitrogen atmosphere for 2 h. The catalytic activity of CoMe/C is characterized by the electrochemical linear sweep voltammetry technique. The onset reduction potential of the catalyst is 0.55 V (vs. SCE) at a scanning rate of 5 mV/s in 0.5 mol/L H2SO4 solution. The formation of the ORR activity sites of CoMe/C is facilitated by metallic β- cobalt.