The deep lateral growth process of the plateau is a hot topic in earth science.As the growth boundary zone of the northeastern Tibetan Plateau,southern Ningxia geomorphic zone is controlled by four major arcuate fault...The deep lateral growth process of the plateau is a hot topic in earth science.As the growth boundary zone of the northeastern Tibetan Plateau,southern Ningxia geomorphic zone is controlled by four major arcuate fault zones(Fig.1),namely Haiyuan fault(HYF),XiangshanTianjingshan fault(XTSF),Yantongshan fault(YTSF).展开更多
A novel bat-like ZnO nanostructure was synthesized on the silicon substrate by simple ther- mal evaporation of zinc powders without any catalyst. Each bat-like nanorod ("nanobat") is composed of a hexagonal head, ...A novel bat-like ZnO nanostructure was synthesized on the silicon substrate by simple ther- mal evaporation of zinc powders without any catalyst. Each bat-like nanorod ("nanobat") is composed of a hexagonal head, a continuous neck and a thin handle. High-resolution transmission electron microscopy and selected area electron diffraction results reveal the single-crystalline feature and the growing direction along [0001] of the nanobat. The vapor- solid mechanism was found suitable to explain the growth process of the nanobat and a schematic model was proposed in detail based on the experimental results.展开更多
A Mg-6Zn-3Gd(mass fraction,%) alloy,noted as ZG63,was coated by different micro-arc oxidation(MAO) processes,and the coating structure and corrosion resistance of the alloy were studied using scanning electron microsc...A Mg-6Zn-3Gd(mass fraction,%) alloy,noted as ZG63,was coated by different micro-arc oxidation(MAO) processes,and the coating structure and corrosion resistance of the alloy were studied using scanning electron microscopy(SEM),glancing angle X-ray diffractometry(GAXRD) and various electrochemical methods.The micro-arc oxidation process consists of three stages and corresponds with different coating structures.In the initial stage,the coating thickness is linearly increased and is controlled by electrochemical polarization.In the second stage,the coating grows mainly inward and accords with parabolic regularity.In the third stage,the loose coating forms and is controlled by local arc light.The looser coating is mainly composed of MgSiO3 and the compact coating is mainly composed of MgO.From micro-arc oxidation stage to local arc light stage,the corrosion resistance of the coated alloy firstly increases and then decreases.The satisfied corrosion resistance corresponds to the coating time ranging from 6 to10 min.展开更多
Fault attributes generally display a consistent power–law-scaling relationship.Based on new 3 D seismic data,however,we found some exceptional fault attribute relationships of lengths(L)–throw(T)(vertical component ...Fault attributes generally display a consistent power–law-scaling relationship.Based on new 3 D seismic data,however,we found some exceptional fault attribute relationships of lengths(L)–throw(T)(vertical component of displacement),overlap zone length(Lo)–width(Wo)from a strike-slip fault system of the Ordovician carbonates in the Tarim Basin.The L–T relationship shows two linear segments with breakup at^40 km in fault length.This presents an exceptional throw increase in the second stage,which is attributed to a localization of vertical displacement and deformation in overlapping zones other than the different fault scales in a mature fault zone.The Lo–Wo relationship in the overlapping zones shows multiply stepped-shape patterns,suggesting multiple fault differential growth and periodic increase in fault size.Therefore,we propose a new alternative growth model of fault attributes in strike-slip fault zones,in which the overlapping zones accumulated localized displacement and deformation in the intracratonic strike-slip fault zone.展开更多
A crop growth model of WOFOST was calibrated and validated through rice field experiments from 2001 to 2004 in Jinhua and Hangzhou, Zhejiang Province. For late rice variety Xiushui 11 and hybrid Xieyou 46, the model w...A crop growth model of WOFOST was calibrated and validated through rice field experiments from 2001 to 2004 in Jinhua and Hangzhou, Zhejiang Province. For late rice variety Xiushui 11 and hybrid Xieyou 46, the model was calibrated to obtain parameter values using the experimental data of years 2001 and 2002, then the parameters were validated by the data obtained during 2003. For single hybrid rice Liangyoupeijiu, the data recorded in 2004 and 2003 were used for calibration and validation, respectively. The main focus of the study was as follows: the WOFOST model is good in simulating rice potential growth in Zhejiang and can be used to analyze the process of rice growth and yield potential. The potential yield obtained from the WOFOST model was about 8100 kg/ha for late rice and 9300 kg/ha for single rice. The current average yield in Jinhua is only about 78% (late rice) and 70% (single rice) of their potential yield. The results of the simulation also showed that the currant practice of management at the middle and late growth stages of rice should be reexamined and improved to reach optimal rice growth.展开更多
Growth process of the NaY zeolite membranes was investigated by fluoride-containing precursor synthesis gel.Compared with the fluoride-free precursor synthesis gel,the irregular NaY zeolite crystals were dissolved int...Growth process of the NaY zeolite membranes was investigated by fluoride-containing precursor synthesis gel.Compared with the fluoride-free precursor synthesis gel,the irregular NaY zeolite crystals were dissolved into amorphous by the fluoride-containing precursor synthesis gel initially,the amorphous contained the Y-type zeolite characteristic bands by the IR characterization.The fine square NaY zeolite crystals arose from the amorphous,which were accumulated and gradually grew into a dense NaY zeolite layer on the support surface after 6.5 h.Because the excessive NaY zeolites were dissolved by the strong alkaline and fluoride-containing precursor synthesis gel,there was plenty of amorphous on NaY zeolites layer for prolonging the crystallization time.The assynthesized NaY zeolite membranes had a good separation performance and repeatability for separation of 10 wt%methanol(MeOH)/methyl methacrylate(MMA) mixture by pervaporation,the flux and separation factor were(1.27 ± 0.07) kg·M^(-2)·h^(-1) and(4900 ± 1500) at 323 K,respectively.Besides,the NaY zeolite membranes were applied to separate the other short chain alcohol from the various alcohol/organic ester and alcohol/organic ether mixtures,the NaY zeolite membranes showed high short chain alcohol perm-selectivity.展开更多
The growth process, palaeoecological features and the function of organisms in reef-building of the Jukoupu bioherm in Hunan are discussed in detail. The bioherm is divided into 10 microfacies. Organisms are very abun...The growth process, palaeoecological features and the function of organisms in reef-building of the Jukoupu bioherm in Hunan are discussed in detail. The bioherm is divided into 10 microfacies. Organisms are very abundant in the reef. Thirty-two genera Belonging to 7 phyla have been recognized. They make up 5 communities composed mainly of stromatopoids, Corals and algae, each of which has its own salient ecological features. An analysis of all communities shows that the organic functions are very complex. The same organisms may possess diverse functions simultaneously as the reef growth enters the late stage. The growth process of the reef may involve five stages' (l)biostrome stage, (2) stabilization stage, (3) frame-type reef-building stage, (4) binding and covering-type reef-building stage, and (5) baffle- type reef -building stage.展开更多
Three kinds of tetrapod-like ZnO nanostructures have been synthesized simultaneously via pure Zn chemical vapor deposition on silicon wafers with (111) orientation (Si (111)) at 920 ℃. X-ray diffraction indicat...Three kinds of tetrapod-like ZnO nanostructures have been synthesized simultaneously via pure Zn chemical vapor deposition on silicon wafers with (111) orientation (Si (111)) at 920 ℃. X-ray diffraction indicates that the nanotetrapods are of wurtzite structure. The morphology and the microstructure of the nanotetrapods are investigated by the scanning electron microscopy. Selected area electron diffraction shows the growth direction, and energy dispersive X-ray spectroscopy reveals the atomic composition ratio of Zn/O. The growth process is briefly discussed. The optical property of the products was also recorded by means of photoluminescence spectroscopy.展开更多
China’s foreign trade from January to August According to Customs figures,China’s total import and export in August reached 2.04 trillion yuan,down 9.7%year on year(the same below).Export was 1.2 trillion yuan,down ...China’s foreign trade from January to August According to Customs figures,China’s total import and export in August reached 2.04 trillion yuan,down 9.7%year on year(the same below).Export was 1.2 trillion yuan,down 6.1%,and import 0.84 trillion yuan,down 14.3%.Trade surplus was 368 billion yuan,an increase of 20.1%.In terms of the U.S.dollar,the total import and export in August reached US$333.5 billion,展开更多
Elucidating the effect of growth periods on the quality of calcium sulfate whiskers(CSWs)prepared from calcium sulfate dihydrate(DH)is imperative.Herein,crystal seeds and whiskers were prepared from DH in a water–gly...Elucidating the effect of growth periods on the quality of calcium sulfate whiskers(CSWs)prepared from calcium sulfate dihydrate(DH)is imperative.Herein,crystal seeds and whiskers were prepared from DH in a water–glycerol system.Longer whiskers were obtained from crystal seeds prepared via hydration of DH for 30 s than via ball milling for 5 min followed by hydration for 20 s.The attachment of cetyltrimethyl ammonium bromide and glycerol additives to the whisker tops promoted whisker growth.The whisker sponges exhibited good thermal barrier properties and compression cycle stability.展开更多
A method to promote aluminum hydroxide crystal growth through pickling Al(OH)_(3)as seed in the ammonia system was proposed to overcome these defects.The experimental results show that,under the conditions of pickling...A method to promote aluminum hydroxide crystal growth through pickling Al(OH)_(3)as seed in the ammonia system was proposed to overcome these defects.The experimental results show that,under the conditions of pickling time of 15 min,the acid concentration of 10%,the addition of 70 g/L pickling-Al(OH)_(3)seed,and the coarse granular Al(OH)_(3)products(d0.5=85.667)can be obtained.The characterization results show that the phase of the product is gibbsite,consistent with the seed.Moreover,the steps and ledges can be formed on pickling Al(OH)_(3)seed surface under the ammonia system,effectively promoting crystal growth.During crystal growth,the roughness of the crystal surface was first increased and then decreased,and the lamellar structure was deposited on the crystal seed surface.The final particles are approximately round,the surface is compact and dense.The growth of the product is surface reaction controlled.In addition,the content of the AlO_(6)unit is increased and contributed to Al(OH)_(3)crystal growth.展开更多
A modified seeded growth process of silica particles with a continuous addition of tetraethyl orthosilicate (TEOS) was presented to control the diameter of silica particles. The diameter of particles was monitored b...A modified seeded growth process of silica particles with a continuous addition of tetraethyl orthosilicate (TEOS) was presented to control the diameter of silica particles. The diameter of particles was monitored by dynamic light scattering to control the addition of TEOS. The increase in the diameter of the silica particles with time and the addition of TEOS was investigated. The diameter of silica seeds increased from 193 nm to 446 nm in 4 h. The final diameter of silica particles was tailored within the range of ±5 nm to the target diameter. Silica particles with diameter of 446 nm were synthesized and assembled into photonic crystals with a pseudo band gap centered at just 1000 nm. The feasibility and practicability of this modified seeded growth process was verified.展开更多
We studied the formation of heartwood in Ery- throphleumfordii Oliv., an endangered rosewood species, by cross-section analysis on 52 stumps aged 28-57 years and arbitrarily sampled from natural forests in South China...We studied the formation of heartwood in Ery- throphleumfordii Oliv., an endangered rosewood species, by cross-section analysis on 52 stumps aged 28-57 years and arbitrarily sampled from natural forests in South China. Width and area of heartwood were positively correlated with age and xylem width (XW), and were independent of annual radial growth. The proportions of heartwood and sapwood areas were equal at about 40 years. The heartwood formation pro- cess was simulated by linear regression of age and XW.展开更多
Several growth models were selected to fit data of dahurian larch plantations using nonlinear regression analysis. The best models were used to construct the site index table' the 2-way volume table and the growth...Several growth models were selected to fit data of dahurian larch plantations using nonlinear regression analysis. The best models were used to construct the site index table' the 2-way volume table and the growth process table. The Chapman-Richards equation is the best model used as the guide curve to form the site index table for dahurian larch plantations.展开更多
The relationship between the solid/liquid interface and the crystal orientation for pure magnesium,which grows in fashion of cellular crystal in unidirectional solidification,was investigated.The results show that the...The relationship between the solid/liquid interface and the crystal orientation for pure magnesium,which grows in fashion of cellular crystal in unidirectional solidification,was investigated.The results show that the energy of the solid/liquid interface is the lowest during cellular crystal growth of pure magnesium;and the solid/liquid interface is covered by the basal face{0001}and by the crystal face made up of three atoms located at the orientation{0001}0100and two atoms located at the inner of magnesium crystal cell.The strongest bond is formed in the direction of 61.9°viating from the growth direction,and the second strong bond is formed in the directions of 8.5°d 47.7°espectively,deviating from the growth direction.The angle between the basal face{0001} and the growth direction is 61.9°he theoretical analysis results are basically consistent with the experimental results from SUSUMU et al.展开更多
Different C_(60) crystals were synthesized by precipitation from a mixture of the good solvent m-xylene and the poor solvent isopropyl alcohol.The samples were characterized by scanning electron microscopy(SEM),Raman ...Different C_(60) crystals were synthesized by precipitation from a mixture of the good solvent m-xylene and the poor solvent isopropyl alcohol.The samples were characterized by scanning electron microscopy(SEM),Raman spectroscopy,thermogravimetric analysis,and high resolution transmission electron microscope(HRTEM).We found that the morphologies and sizes of the samples could be controlled by adjusting the volume ratio between the good and poor solvents.Especially,an unexpected short flower column-like crystal was synthesized at low ratios(from 1:6 to 1:12).Room temperature photoluminescence(PL)and HRTEM studies of the C_(60) crystal samples reveal that the PL efficiency of the crystals decreases with increasing crystalline order and that the disordered C_(60) crystals synthesized at the ratio of 1:2 show 10 times higher PL efficiency than that of pristine C_(60).The mechanism of the growth process of these C_(60) crystals was also studied by replacing the good solvents m-xylene with toluene and mesitylene.展开更多
Business growth and development are similar to a selforganization evolution system. This paper intends to explore the context, drive and process within enterprise self-organization evolution from a conceptual perspect...Business growth and development are similar to a selforganization evolution system. This paper intends to explore the context, drive and process within enterprise self-organization evolution from a conceptual perspective. And an enterprise evolution model can be applied on the basis of ecological logistic equations to approach the elementary process and the growth stage of organization. Moreover,the influence of diverse variable on the evolution of enterprise growth is discussed. At last, the study concludes that new structures and functions can emerge within organizations and enterprises,which contribute to transformation and upgrade during their self-organization evolution.展开更多
Here, a new idea was proposed for template-free synthesis of hierarchical m-ZrO2 nanorods and "their" possible formation mechanism based on a series of chemical reactions by simple hydrothermal method. The tradition...Here, a new idea was proposed for template-free synthesis of hierarchical m-ZrO2 nanorods and "their" possible formation mechanism based on a series of chemical reactions by simple hydrothermal method. The traditional preparation methods of hierarchical ZrO2 nanorods involved inexpensive equipment, complicated process, and high production cost. The as-synthesized products composed of many nanorods with 180-200 nm in diameter and 5-7 μm in length. The fi nal product after annealing involved hierarchical monoclinic ZrO2(m-ZrO2) nanorods, namely, the big nanorod was made up of many small nanorods with 40-50 nm in diameter and 500-600 nm in length. The experimental results were useful in understanding the chemical properties of ZrB2 and ZrO2 and the design of the derivatives for m-ZrO2 nanomaterials.展开更多
Designing new materials and architectures to maintain activity and stability requires a better understanding on the anticorrosion dynamics of nanoparticles.Under-coordinated atoms on the surface of nanoparticles can b...Designing new materials and architectures to maintain activity and stability requires a better understanding on the anticorrosion dynamics of nanoparticles.Under-coordinated atoms on the surface of nanoparticles can be protected by deposited shells.Real-time observation on how protective shells grow and play a role is challenging but worthwhile.Here,protective effects of AuCl_(3) shells on Au nanobipyramids(NBPs)are studied in HAuCl_(4) aqueous solutions by in-situ liquid cell transmission electron microscopy(LCTEM).This study is the first to observe the formation of Au-AuCl_(3) core-shell nanostructure and the corresponding anticorrosion behaviors of AuCl_(3) deposited shell.The presence of CTAB can substantially influence the growth mode and structure of AuCl_(3) shell,by a direct or indirect way,intervene the dissolution of Au NBP.These growth or dissolution kinetics here revealed at the nanoscale provide insights towards engineering of the surface anticorrosion to pursue Au nanoparticles with improved stability in acidic environment.展开更多
In the northern South China Sea, the accumulation of enormous quantities of terrigenous sediment during Cenozoic rendered well-developed polymetallic nodules very rare. In this study, we analyzed a polymetallic nodule...In the northern South China Sea, the accumulation of enormous quantities of terrigenous sediment during Cenozoic rendered well-developed polymetallic nodules very rare. In this study, we analyzed a polymetallic nodule from the northwestern conti- nental margin of the South China Sea using microscopic mineralogical observation, electron probes, X-ray diffraction (XRD), ICP-MS, and Be isotope dating. We found the nodule's shell layers rich in different types of microstructures, including co- lumnar, laminar, stack-like, petal-like, and porphyritic structures. The major mineral components of the nodule are MnO2. Unlike nodules from the eastern Pacific basin, this nodule has high contents in Fe, Si, A1, and REEs but low contents in Mn, Cu, Co, and Ni. The Mn/Fe ratio is also low and the average REEs content is 1370.4 ppm. There is a strong positive anomaly of Ce; and the Be (beryllium) isotope dating shows the initial time of growth of the nodule to be about 3.29 Ma. The inner compact layer formed from 3.29 Ma to about 1.83 Ma. The laminar and stack-like structures and the low contents of the terri- genous elements such as Fe, Si, REE, and A1 indicate the paleoceanographical environment with weak undersea currents and favorable oxidizing conditions. From 1.83 Ma to 0.73 Ma, the growth rate of the nodule increased by about 3%; the micro- structures formed during this period are stack-like and columnar. The contents of Si and A1 are increased by nearly 10%, indi- cating an increase of terrigenous sediment input in the northern South China Sea. The content of Ce is decreased by about 16% indicating a significant weakening of the oxidizing conditions at the seabed. From 0.73 Ma to 0.69 Ma, the growth rate of the nodule rapidly rose up to 8.27 times that of the nodule's average growth rate, and the contents of Fe, A1, and REEs in the layer also increased, forming a loose layer characterized by oolitic, granular, porphyritic, and petal-like structures, indicating the paleoceanographical environment with a high sedimemtation rate and abundant supply of terrigenous sediment in the northern South China Sea. From 0.69 Ma to 0.22 Ma, the growth rate of the nodule suddenly slowed and the outer compact layer formed. Contents of Fe, Si, REE, A1, Mn, Cu, Co, and Ni in this layer were significantly lower than in other layers. The main structures of the layer are laminar and fissure filling structures. These reflect the paleoceanographical environment with stable undersea currents, poor oxidizing conditions, and other conditions not conducive to nodule growth. The growth process of nodule S04-1DG-1 was found to respond sensitively to the changes of the paleoceanographical environment of the northern South China Sea during the late Cenozoic.展开更多
基金supported by the Geological Survey Project of China Geological Survey(Grant No.DD20190018)
文摘The deep lateral growth process of the plateau is a hot topic in earth science.As the growth boundary zone of the northeastern Tibetan Plateau,southern Ningxia geomorphic zone is controlled by four major arcuate fault zones(Fig.1),namely Haiyuan fault(HYF),XiangshanTianjingshan fault(XTSF),Yantongshan fault(YTSF).
文摘A novel bat-like ZnO nanostructure was synthesized on the silicon substrate by simple ther- mal evaporation of zinc powders without any catalyst. Each bat-like nanorod ("nanobat") is composed of a hexagonal head, a continuous neck and a thin handle. High-resolution transmission electron microscopy and selected area electron diffraction results reveal the single-crystalline feature and the growing direction along [0001] of the nanobat. The vapor- solid mechanism was found suitable to explain the growth process of the nanobat and a schematic model was proposed in detail based on the experimental results.
文摘A Mg-6Zn-3Gd(mass fraction,%) alloy,noted as ZG63,was coated by different micro-arc oxidation(MAO) processes,and the coating structure and corrosion resistance of the alloy were studied using scanning electron microscopy(SEM),glancing angle X-ray diffractometry(GAXRD) and various electrochemical methods.The micro-arc oxidation process consists of three stages and corresponds with different coating structures.In the initial stage,the coating thickness is linearly increased and is controlled by electrochemical polarization.In the second stage,the coating grows mainly inward and accords with parabolic regularity.In the third stage,the loose coating forms and is controlled by local arc light.The looser coating is mainly composed of MgSiO3 and the compact coating is mainly composed of MgO.From micro-arc oxidation stage to local arc light stage,the corrosion resistance of the coated alloy firstly increases and then decreases.The satisfied corrosion resistance corresponds to the coating time ranging from 6 to10 min.
基金partly supported by the National Natural Science Foundation of China(Grant No.91955204)Science and Technology Cooperation Project of the CNPC-SWPU Innovation Alliance(Grant No.2020CX010300)。
文摘Fault attributes generally display a consistent power–law-scaling relationship.Based on new 3 D seismic data,however,we found some exceptional fault attribute relationships of lengths(L)–throw(T)(vertical component of displacement),overlap zone length(Lo)–width(Wo)from a strike-slip fault system of the Ordovician carbonates in the Tarim Basin.The L–T relationship shows two linear segments with breakup at^40 km in fault length.This presents an exceptional throw increase in the second stage,which is attributed to a localization of vertical displacement and deformation in overlapping zones other than the different fault scales in a mature fault zone.The Lo–Wo relationship in the overlapping zones shows multiply stepped-shape patterns,suggesting multiple fault differential growth and periodic increase in fault size.Therefore,we propose a new alternative growth model of fault attributes in strike-slip fault zones,in which the overlapping zones accumulated localized displacement and deformation in the intracratonic strike-slip fault zone.
文摘A crop growth model of WOFOST was calibrated and validated through rice field experiments from 2001 to 2004 in Jinhua and Hangzhou, Zhejiang Province. For late rice variety Xiushui 11 and hybrid Xieyou 46, the model was calibrated to obtain parameter values using the experimental data of years 2001 and 2002, then the parameters were validated by the data obtained during 2003. For single hybrid rice Liangyoupeijiu, the data recorded in 2004 and 2003 were used for calibration and validation, respectively. The main focus of the study was as follows: the WOFOST model is good in simulating rice potential growth in Zhejiang and can be used to analyze the process of rice growth and yield potential. The potential yield obtained from the WOFOST model was about 8100 kg/ha for late rice and 9300 kg/ha for single rice. The current average yield in Jinhua is only about 78% (late rice) and 70% (single rice) of their potential yield. The results of the simulation also showed that the currant practice of management at the middle and late growth stages of rice should be reexamined and improved to reach optimal rice growth.
基金supported by the National Natural Science Foundation of China (Grant No. 21868012 and 21968009)Jiangxi Provincial Department of Science and Technology (20171BCB24005, 20181ACH80003, 20192ACB80003 and 20192BBH80024)。
文摘Growth process of the NaY zeolite membranes was investigated by fluoride-containing precursor synthesis gel.Compared with the fluoride-free precursor synthesis gel,the irregular NaY zeolite crystals were dissolved into amorphous by the fluoride-containing precursor synthesis gel initially,the amorphous contained the Y-type zeolite characteristic bands by the IR characterization.The fine square NaY zeolite crystals arose from the amorphous,which were accumulated and gradually grew into a dense NaY zeolite layer on the support surface after 6.5 h.Because the excessive NaY zeolites were dissolved by the strong alkaline and fluoride-containing precursor synthesis gel,there was plenty of amorphous on NaY zeolites layer for prolonging the crystallization time.The assynthesized NaY zeolite membranes had a good separation performance and repeatability for separation of 10 wt%methanol(MeOH)/methyl methacrylate(MMA) mixture by pervaporation,the flux and separation factor were(1.27 ± 0.07) kg·M^(-2)·h^(-1) and(4900 ± 1500) at 323 K,respectively.Besides,the NaY zeolite membranes were applied to separate the other short chain alcohol from the various alcohol/organic ester and alcohol/organic ether mixtures,the NaY zeolite membranes showed high short chain alcohol perm-selectivity.
文摘The growth process, palaeoecological features and the function of organisms in reef-building of the Jukoupu bioherm in Hunan are discussed in detail. The bioherm is divided into 10 microfacies. Organisms are very abundant in the reef. Thirty-two genera Belonging to 7 phyla have been recognized. They make up 5 communities composed mainly of stromatopoids, Corals and algae, each of which has its own salient ecological features. An analysis of all communities shows that the organic functions are very complex. The same organisms may possess diverse functions simultaneously as the reef growth enters the late stage. The growth process of the reef may involve five stages' (l)biostrome stage, (2) stabilization stage, (3) frame-type reef-building stage, (4) binding and covering-type reef-building stage, and (5) baffle- type reef -building stage.
文摘Three kinds of tetrapod-like ZnO nanostructures have been synthesized simultaneously via pure Zn chemical vapor deposition on silicon wafers with (111) orientation (Si (111)) at 920 ℃. X-ray diffraction indicates that the nanotetrapods are of wurtzite structure. The morphology and the microstructure of the nanotetrapods are investigated by the scanning electron microscopy. Selected area electron diffraction shows the growth direction, and energy dispersive X-ray spectroscopy reveals the atomic composition ratio of Zn/O. The growth process is briefly discussed. The optical property of the products was also recorded by means of photoluminescence spectroscopy.
文摘China’s foreign trade from January to August According to Customs figures,China’s total import and export in August reached 2.04 trillion yuan,down 9.7%year on year(the same below).Export was 1.2 trillion yuan,down 6.1%,and import 0.84 trillion yuan,down 14.3%.Trade surplus was 368 billion yuan,an increase of 20.1%.In terms of the U.S.dollar,the total import and export in August reached US$333.5 billion,
基金supported by the Degradable Plastics Engineering Research Center of Yunnan Provincial Education Department(KKPU202205001).
文摘Elucidating the effect of growth periods on the quality of calcium sulfate whiskers(CSWs)prepared from calcium sulfate dihydrate(DH)is imperative.Herein,crystal seeds and whiskers were prepared from DH in a water–glycerol system.Longer whiskers were obtained from crystal seeds prepared via hydration of DH for 30 s than via ball milling for 5 min followed by hydration for 20 s.The attachment of cetyltrimethyl ammonium bromide and glycerol additives to the whisker tops promoted whisker growth.The whisker sponges exhibited good thermal barrier properties and compression cycle stability.
基金Funded by the National Natural Science Foundation of China(No.51974188)the Liaoning Revitalization Talents Program(No.XLYC2008014)。
文摘A method to promote aluminum hydroxide crystal growth through pickling Al(OH)_(3)as seed in the ammonia system was proposed to overcome these defects.The experimental results show that,under the conditions of pickling time of 15 min,the acid concentration of 10%,the addition of 70 g/L pickling-Al(OH)_(3)seed,and the coarse granular Al(OH)_(3)products(d0.5=85.667)can be obtained.The characterization results show that the phase of the product is gibbsite,consistent with the seed.Moreover,the steps and ledges can be formed on pickling Al(OH)_(3)seed surface under the ammonia system,effectively promoting crystal growth.During crystal growth,the roughness of the crystal surface was first increased and then decreased,and the lamellar structure was deposited on the crystal seed surface.The final particles are approximately round,the surface is compact and dense.The growth of the product is surface reaction controlled.In addition,the content of the AlO_(6)unit is increased and contributed to Al(OH)_(3)crystal growth.
文摘A modified seeded growth process of silica particles with a continuous addition of tetraethyl orthosilicate (TEOS) was presented to control the diameter of silica particles. The diameter of particles was monitored by dynamic light scattering to control the addition of TEOS. The increase in the diameter of the silica particles with time and the addition of TEOS was investigated. The diameter of silica seeds increased from 193 nm to 446 nm in 4 h. The final diameter of silica particles was tailored within the range of ±5 nm to the target diameter. Silica particles with diameter of 446 nm were synthesized and assembled into photonic crystals with a pseudo band gap centered at just 1000 nm. The feasibility and practicability of this modified seeded growth process was verified.
基金financially supported by the Special Research Program for Public-welfare Forestry(No.201204301-2)National Nonprofit Institute Research Grant of RITF(No.RITFKYYW2010-05)
文摘We studied the formation of heartwood in Ery- throphleumfordii Oliv., an endangered rosewood species, by cross-section analysis on 52 stumps aged 28-57 years and arbitrarily sampled from natural forests in South China. Width and area of heartwood were positively correlated with age and xylem width (XW), and were independent of annual radial growth. The proportions of heartwood and sapwood areas were equal at about 40 years. The heartwood formation pro- cess was simulated by linear regression of age and XW.
文摘Several growth models were selected to fit data of dahurian larch plantations using nonlinear regression analysis. The best models were used to construct the site index table' the 2-way volume table and the growth process table. The Chapman-Richards equation is the best model used as the guide curve to form the site index table for dahurian larch plantations.
基金Project(2007T078)supported by the Outstanding Innovation Team in Colleges and Universities of Education Department of Liaoning Province,China
文摘The relationship between the solid/liquid interface and the crystal orientation for pure magnesium,which grows in fashion of cellular crystal in unidirectional solidification,was investigated.The results show that the energy of the solid/liquid interface is the lowest during cellular crystal growth of pure magnesium;and the solid/liquid interface is covered by the basal face{0001}and by the crystal face made up of three atoms located at the orientation{0001}0100and two atoms located at the inner of magnesium crystal cell.The strongest bond is formed in the direction of 61.9°viating from the growth direction,and the second strong bond is formed in the directions of 8.5°d 47.7°espectively,deviating from the growth direction.The angle between the basal face{0001} and the growth direction is 61.9°he theoretical analysis results are basically consistent with the experimental results from SUSUMU et al.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11504269 and 11504267)Tianjin Natural Science Foundation(Grant No.20JCQNJC00660)the Program for Innovative Research in University of Tianjin(Grant No.TD13-5077).
文摘Different C_(60) crystals were synthesized by precipitation from a mixture of the good solvent m-xylene and the poor solvent isopropyl alcohol.The samples were characterized by scanning electron microscopy(SEM),Raman spectroscopy,thermogravimetric analysis,and high resolution transmission electron microscope(HRTEM).We found that the morphologies and sizes of the samples could be controlled by adjusting the volume ratio between the good and poor solvents.Especially,an unexpected short flower column-like crystal was synthesized at low ratios(from 1:6 to 1:12).Room temperature photoluminescence(PL)and HRTEM studies of the C_(60) crystal samples reveal that the PL efficiency of the crystals decreases with increasing crystalline order and that the disordered C_(60) crystals synthesized at the ratio of 1:2 show 10 times higher PL efficiency than that of pristine C_(60).The mechanism of the growth process of these C_(60) crystals was also studied by replacing the good solvents m-xylene with toluene and mesitylene.
文摘Business growth and development are similar to a selforganization evolution system. This paper intends to explore the context, drive and process within enterprise self-organization evolution from a conceptual perspective. And an enterprise evolution model can be applied on the basis of ecological logistic equations to approach the elementary process and the growth stage of organization. Moreover,the influence of diverse variable on the evolution of enterprise growth is discussed. At last, the study concludes that new structures and functions can emerge within organizations and enterprises,which contribute to transformation and upgrade during their self-organization evolution.
基金Funded by the Ministry of Science and Technology of China(S2010GR0771)the National Natural Science Foundation of China(51161140399)
文摘Here, a new idea was proposed for template-free synthesis of hierarchical m-ZrO2 nanorods and "their" possible formation mechanism based on a series of chemical reactions by simple hydrothermal method. The traditional preparation methods of hierarchical ZrO2 nanorods involved inexpensive equipment, complicated process, and high production cost. The as-synthesized products composed of many nanorods with 180-200 nm in diameter and 5-7 μm in length. The fi nal product after annealing involved hierarchical monoclinic ZrO2(m-ZrO2) nanorods, namely, the big nanorod was made up of many small nanorods with 40-50 nm in diameter and 500-600 nm in length. The experimental results were useful in understanding the chemical properties of ZrB2 and ZrO2 and the design of the derivatives for m-ZrO2 nanomaterials.
基金support from the National Natural Science Foundation of China(51801024)Natural Science Foundation of the Jiangsu Higher Education Institutions of China(22KJD510006,22KJB110012)Jiangsu Open University“14th Five-Year”2023 Annual Scientific Research Planning Project(2023XK004).
文摘Designing new materials and architectures to maintain activity and stability requires a better understanding on the anticorrosion dynamics of nanoparticles.Under-coordinated atoms on the surface of nanoparticles can be protected by deposited shells.Real-time observation on how protective shells grow and play a role is challenging but worthwhile.Here,protective effects of AuCl_(3) shells on Au nanobipyramids(NBPs)are studied in HAuCl_(4) aqueous solutions by in-situ liquid cell transmission electron microscopy(LCTEM).This study is the first to observe the formation of Au-AuCl_(3) core-shell nanostructure and the corresponding anticorrosion behaviors of AuCl_(3) deposited shell.The presence of CTAB can substantially influence the growth mode and structure of AuCl_(3) shell,by a direct or indirect way,intervene the dissolution of Au NBP.These growth or dissolution kinetics here revealed at the nanoscale provide insights towards engineering of the surface anticorrosion to pursue Au nanoparticles with improved stability in acidic environment.
基金supported by National Natural Science Foundation of China(Grant Nos.40972079,41172015 and 41030853)National Basic Research Program of China(Grant No.2007CB411703)Education Department of Hebei Province(Grant Nos.2009443,2010248)
文摘In the northern South China Sea, the accumulation of enormous quantities of terrigenous sediment during Cenozoic rendered well-developed polymetallic nodules very rare. In this study, we analyzed a polymetallic nodule from the northwestern conti- nental margin of the South China Sea using microscopic mineralogical observation, electron probes, X-ray diffraction (XRD), ICP-MS, and Be isotope dating. We found the nodule's shell layers rich in different types of microstructures, including co- lumnar, laminar, stack-like, petal-like, and porphyritic structures. The major mineral components of the nodule are MnO2. Unlike nodules from the eastern Pacific basin, this nodule has high contents in Fe, Si, A1, and REEs but low contents in Mn, Cu, Co, and Ni. The Mn/Fe ratio is also low and the average REEs content is 1370.4 ppm. There is a strong positive anomaly of Ce; and the Be (beryllium) isotope dating shows the initial time of growth of the nodule to be about 3.29 Ma. The inner compact layer formed from 3.29 Ma to about 1.83 Ma. The laminar and stack-like structures and the low contents of the terri- genous elements such as Fe, Si, REE, and A1 indicate the paleoceanographical environment with weak undersea currents and favorable oxidizing conditions. From 1.83 Ma to 0.73 Ma, the growth rate of the nodule increased by about 3%; the micro- structures formed during this period are stack-like and columnar. The contents of Si and A1 are increased by nearly 10%, indi- cating an increase of terrigenous sediment input in the northern South China Sea. The content of Ce is decreased by about 16% indicating a significant weakening of the oxidizing conditions at the seabed. From 0.73 Ma to 0.69 Ma, the growth rate of the nodule rapidly rose up to 8.27 times that of the nodule's average growth rate, and the contents of Fe, A1, and REEs in the layer also increased, forming a loose layer characterized by oolitic, granular, porphyritic, and petal-like structures, indicating the paleoceanographical environment with a high sedimemtation rate and abundant supply of terrigenous sediment in the northern South China Sea. From 0.69 Ma to 0.22 Ma, the growth rate of the nodule suddenly slowed and the outer compact layer formed. Contents of Fe, Si, REE, A1, Mn, Cu, Co, and Ni in this layer were significantly lower than in other layers. The main structures of the layer are laminar and fissure filling structures. These reflect the paleoceanographical environment with stable undersea currents, poor oxidizing conditions, and other conditions not conducive to nodule growth. The growth process of nodule S04-1DG-1 was found to respond sensitively to the changes of the paleoceanographical environment of the northern South China Sea during the late Cenozoic.