The carbon dissolution in solvent plays a key role in the process of solution growth route for SiC single crystal,which could determine the growth rate and quality of the products.However,the carbon dissolving ability...The carbon dissolution in solvent plays a key role in the process of solution growth route for SiC single crystal,which could determine the growth rate and quality of the products.However,the carbon dissolving ability of binary alloy solvent still needs to be improved.Here,we demonstrate the improved carbon dissolution and enlarged carbon supersaturation in Cr-Ce-Si ternary solvent,showing great potential for SiC solution growth.The phase relations of Cr-Ce-Si-C system were determined by using CALPHAD method based on thermodynamic parameters of CeCr_(2)Si_(2)C.It is indicated that the Cr-Ce-Si ternary solvent shows much larger carbon solubility in temperature range from 1700 to 2000℃compared to Cr-Si binary one,Furthermore,the carbon supersaturation in solvent is also significantly increased in low temperature range after the addition of Ce,leading to a rapid growth rate.Our work not only demonstrates the feasibility of adding Ce in the alloy solvent for rapid growth of SiC crystal,but also provides an example for investigating the C solubility in ternary solvent.展开更多
Spontaneous nucleation of SiC particles and giant macroscopic steps result in the surface roughness of the grown crystal for the top-seeded solution growth of SiC crystal.To suppress the surface roughness,the temperat...Spontaneous nucleation of SiC particles and giant macroscopic steps result in the surface roughness of the grown crystal for the top-seeded solution growth of SiC crystal.To suppress the surface roughness,the temperature gradient was carefully adjusted by changing the relative position of the crucible and induction coils.The numerical simulation and experimental results show that the surface morphology of the grown crystal becomes smoother and there are fewer spontaneous nucleation particles attached to the growth surface with the decrease in the relative crucible position,due to the increase of temperature at the entire solution surface and the reducing of temperature gradient near the growth surface.Accordingly,a lower temperature gradient,a larger solution velocity,a higher carbon concentration,and a smaller carbon supersaturation near the growth surface can be obtained when the relative position between the crucible and the induction coil is 70 mm,which is demonstrated to be the most favorable for the elimination of spontaneous nucleation of small SiC particles and suppressing surface roughening with the full width at half maximum(FWHM)of 37.5 arcsec of 4Hsingle bondSiC crystals.展开更多
One-dimensional （1D） ZnO nanostructures have been studied intensively and extensively over the last decade not only for their remarkable chemical and physical properties, but also for their diverse current and futur...One-dimensional （1D） ZnO nanostructures have been studied intensively and extensively over the last decade not only for their remarkable chemical and physical properties, but also for their diverse current and future technological applications. This article gives a comprehensive overview of the progress that has been made within the context of 1D ZnO nanostructures synthesized via wet chemical methods. We will cover the synthetic methodologies and the corresponding growth mechanisms, various nanostructures grown, their doping and alloying, and position-controlled growth on substrates. Finally, we will review their functional properties in catalysis, hydrophobic surface modification, sensing, and electronic, optical, optoelectronic, and energy harvesting devices.展开更多
The growth of polycrystalline silicon layers on glass from tin solutions at low temperatures is presented.This approach is based on the steady-state solution growth of Si crystallites on nanocrystalline seed layers, w...The growth of polycrystalline silicon layers on glass from tin solutions at low temperatures is presented.This approach is based on the steady-state solution growth of Si crystallites on nanocrystalline seed layers, which are prepared in a preceding process step. Scanning electron microscopy and atomic force microscopy investigations reveal details about the seed layer surfaces, which consist of small hillocks, as well as about Sn inclusions and gaps along the glass substrate after solution growth. The successful growth of continuous microcrystalline Si layers with grain sizes up to several ten micrometers shows the feasibility of the process and makes it interesting for photovoltaics.展开更多
The stability of the shapes of crystal growth face and dissolution face in a two-dimensional mathematical model of crystal growth from solution under microgravity is studied. It is proved that the stable shapes of cry...The stability of the shapes of crystal growth face and dissolution face in a two-dimensional mathematical model of crystal growth from solution under microgravity is studied. It is proved that the stable shapes of crystal growth face and dissolution face do exist, which are suitably shaped curves with their upper parts inclined backward properly.The stable shapes of crystal growth faces and dissolution faces are calculated for various values of parameters, Ra, Pr and Sc. It is shown that the stronger the convection relative to the diffusion in solution is, the more backward the upperparts of the stable crystal growth face and dissolution face are inclined. The orientation and the shape of dissolution face hardly affect the stable shape of crystal growth face and vice versa.展开更多
In this paper we give a priori estimates for the maximum modulus of generalizedsolulions of the quasilinear elliplic equations irith anisotropic growth condition.
The 1.55μm laser technology is widely applied in military,information communication,biomedicine and other fields.With the deepening development of these application areas,the demand for novel 1.55μm laser gain media...The 1.55μm laser technology is widely applied in military,information communication,biomedicine and other fields.With the deepening development of these application areas,the demand for novel 1.55μm laser gain media is becoming increasingly urgent.This study reports a novel Yb^(3+),Er^(3+)co-doped KBa_(0.94)Ca_(0.06)Y(MoO_(4))_(3) (KBCYM)crystal.In this crystal,Yb^(3+)serves as a sensitizer,significantly enhancing the emission intensity of Er^(3+)in both visible and near-infrared bands.Notably,when the concentration of Yb^(3+)reaches 6 mol%,the emission intensity peaks at 1.55μm.Optical cross-section calculations reveal that the crystal exhibits a low laser pumping threshold at this concentration,demonstrating its potential as a laser gain medium.However,the crystal inevitably generates thermal effects during operation,which may adversely affect its performance.Therefore,real-time monitoring of the operating temperature is crucial.The thermal stability of the crystal was evaluated by measuring the temperature dependence of its luminescence intensity in the near-infrared band.Remarkably,even when the temperature rises to 553 K,the emission intensity at 1.55μm only decreases by 10.9%.Additionally,the temperature sensing performance was evaluated using fluorescence intensity ratio techniques,yielding absolute and relative sensitivities of 0.00981 K^(-1)at 453 K and 1.32%/K at 303 K,respectively,highlighting its potential for optical temperature sensing.Finally,through leveraging the unique properties of Yb^(3+),Er^(3+):KBCYM crystals,we successfully developed 1.55μm luminescent optical devices with practical applications.These devices not only exhibit efficient luminescent performance,but also possess a self-temperature measu rement functio n,opening up new avenues for the further development of laser technology.展开更多
KTb（WO4）2（KTW） single crystal with dimensions up to 30 mm×30 mm 10 mm was grown by the top-seeded solution growth （TSSG） method for the first time. The crystal structure was refined at room temperature by u...KTb（WO4）2（KTW） single crystal with dimensions up to 30 mm×30 mm 10 mm was grown by the top-seeded solution growth （TSSG） method for the first time. The crystal structure was refined at room temperature by using single crystal X-ray diffiaction data. Ab- sorption and fluorescence spectra were measured at room temperature. The fluorescence lifetime of KTb（WO4）2 was 114 μs. The specific heat of the KTh（WO4）2 crystal was also measured at room temperature.展开更多
In this work, flowerlike ZnO micro/nanostructures assembled from nanorods are obtained through a facile hydrothermal route. The experimental results indicated that the as-synthesized ZnO microflowers have an average d...In this work, flowerlike ZnO micro/nanostructures assembled from nanorods are obtained through a facile hydrothermal route. The experimental results indicated that the as-synthesized ZnO microflowers have an average diameter of 2 μm, composed of nanorods of an average diameter of 200 nm and a tapered morphology.ZnO with other morphologies were also obtained by varying the reaction conditions. Systematical conditiondependent experiments were conducted to reveal the growth mechansim of the microflowers. It is suggested that the zinc source types, solution p H value, and reaction temperature, as well as reaction time are responsible for the variations of ZnO morphology. Luminescence properties of ZnO microflowers were investigated through monitoring different parts of nanorods, showing good optical quality.展开更多
A facile one-step method was developed for the fabrication of hierarchical ZnO film on substrate. Neither seed nor catalyst layer is necessary for the growth of hierarchical ZnO film. Three kinds of nucleation process...A facile one-step method was developed for the fabrication of hierarchical ZnO film on substrate. Neither seed nor catalyst layer is necessary for the growth of hierarchical ZnO film. Three kinds of nucleation process were found, and the influences of growth time, growth electrolyte, growth temperature on the morphology of ZnO film were evaluated. Hierarchical ZnO film can absorb more than 97% of incident photons with wavelength shorter than 380 nm. Such hierarchical ZnO film would be a promising scaffold for photoelectrochemical application.展开更多
The phase diagram, growth and optical property of LaBWO6 crystal are reported. LaBWO6 crystal melts congruently at 1078 ℃. Based on the pseudo-ternary phase diagram of LaBWO6-（Li2WO4/LiF） -B203, the LaBWO6 crystals...The phase diagram, growth and optical property of LaBWO6 crystal are reported. LaBWO6 crystal melts congruently at 1078 ℃. Based on the pseudo-ternary phase diagram of LaBWO6-（Li2WO4/LiF） -B203, the LaBWO6 crystals have been firstly grown by the flux method. LaBWO6 crystal crystallizes in the orthorhombic system, space group P222 with a = 4.1, b = 10.31 and c = 21.71 A. LaBWO6 Crystal exhibits high transparency in a range from 327 to 1100 nm. The absorption edge of the crystal in the UV range is at 293 nm. The SHG efficient of LaBWO6 crystal is 0.3 times as large as that of the KDP crystal.展开更多
For a continuous, increasing function ω ： R^＋ →R^＋／{0} of finite exponential type, this paper introduces the set Z（A, ω） of all x in a Banach space X for which the second order abstract differential equation ...For a continuous, increasing function ω ： R^＋ →R^＋／{0} of finite exponential type, this paper introduces the set Z（A, ω） of all x in a Banach space X for which the second order abstract differential equation （2） has a mild solution such that [ω（t）]^-1u（t,x） is uniformly continues on R^＋, and show that Z（A, ω） is a maximal Banach subspace continuously embedded in X, where A ∈ B（X） is closed. Moreover, A[z（A,ω） generates an O（ω（t）） strongly continuous cosine operator function family.展开更多
The method that we can choose is only the more complicated flux growth techniqUe.A broad range of fluxes which contain B_(2)O_(3),PbO_(2),PbF_(2)and alkali halides etc.have been therefore attemped in our lab、in order...The method that we can choose is only the more complicated flux growth techniqUe.A broad range of fluxes which contain B_(2)O_(3),PbO_(2),PbF_(2)and alkali halides etc.have been therefore attemped in our lab、in order to grow large high quality LBO crystals.Most of them seems infavorable to the growth of LBO crystals,and PbO and PbF_(2)also have to be excluded from our considerations although these additives can reduce the viscosity of the growth solution and enhance growth rate,since Pb^(2+)ion can easily enter into the crystal lat-tice and may cause the shatter of crystal thereby.展开更多
Cubic silicon carbide(3C-SiC)has superior mobility and thermal conduction over that of widely applied hexagonal 4H-SiC.Moreover,much lower concentration of interfacial traps between insulating oxide gate and 3C-SiC he...Cubic silicon carbide(3C-SiC)has superior mobility and thermal conduction over that of widely applied hexagonal 4H-SiC.Moreover,much lower concentration of interfacial traps between insulating oxide gate and 3C-SiC helps fabricate reliable and long-life devices like metal-oxidesemiconductor field effect transistors.However,the growth of high-quality and wafer-scale 3C-SiC crystals has remained a big challenge up to now despite decades-long efforts by researchers because of its easy transformation into other polytypes during growth,limiting the development of 3C-SiC-based devices.Herein,we report that 3C-SiC can be made thermodynamically favored from nucleation to growth on a 4H-SiC substrate by top-seeded solution growth technique,beyond what is expected by classical nucleation theory.This enables the steady growth of high-quality and large-size 3C-SiC crystals(2-4-inch in diameter and 4.0-10.0 mm in thickness)sustainable.The as-grown 3C-SiC crystals are free of other polytypes and have high-crystalline quality.Our findings broaden the mechanism of hetero-seed crystal growth and provide a feasible route to mass production of 3C-SiC crystals,offering new opportunities to develop power electronic devices potentially with better performances than those based on 4H-SiC.展开更多
Sodium acid phthalate C<sub>8</sub>H<sub>5</sub>NaO<sub>4</sub> is one of the suitable semiorganic single crystals hired in second harmonic generation conversion applications. In th...Sodium acid phthalate C<sub>8</sub>H<sub>5</sub>NaO<sub>4</sub> is one of the suitable semiorganic single crystals hired in second harmonic generation conversion applications. In the present work, optically transparent Benzophenone doped with sodium acid phthalate (SAPB) single crystals were grown successfully by slow evaporation solution technique. Single crystal XRD analyses exposed that the crystal lattice of SAPB crystal is a monoclinic crystal system with unit cell parameters <em>a</em> = 6.77 <span style="white-space:nowrap;"><span style="white-space:nowrap;"><span class="color-dim" style="box-sizing:border-box;color:#636363;font-family:Montserrat, system-ui, -apple-system, BlinkMacSystemFont, "font-size:40px;text-align:center;white-space:normal;background-color:#FFFFFF;"><span style="white-space:nowrap;">Å</span></span><span class="color-dim" style="box-sizing:border-box;color:#636363;font-family:Montserrat, system-ui, -apple-system, BlinkMacSystemFont, "font-size:40px;text-align:center;white-space:normal;background-color:#FFFFFF;"></span></span></span>, <em>b </em>= 9.31 <span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">Å</span></span></span>, <em>c</em> = 13.58 <span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">Å</span></span></span>, and space group B2cb. The crystalline nature of SAPB material was confirmed by powder XRD pattern. The functional groups present in the grown crystals were identified by the FTIR analysis ranging between 4000 and 500 cm<sup><span style="white-space:nowrap;"><span class="color-dim" style="box-sizing:border-box;color:#636363;font-family:Montserrat, system-ui, -apple-system, BlinkMacSystemFont, " font-size:40px;text-align:center;white-space:normal;background-color:#ffffff;"=""><span style="white-space:nowrap;">−</span></span><span class="color-dim" style="box-sizing:border-box;color:#636363;font-family:Montserrat, system-ui, -apple-system, BlinkMacSystemFont, " font-size:40px;text-align:center;white-space:normal;background-color:#ffffff;"=""></span></span>1</sup>. The optical transparency and band gap of grown crystals were measured from UV-Visible spectroscopy. The fluorescence emission spectrum of the SAPB crystal having a strong Yellow emission peak at 574 nm and the red emission at 631 nm are identified. The Vickers microhardness number (<em>H<sub>v</sub></em>) increases with increasing load. Meyer’s index number (<em>n</em>) calculated from <em>H<sub>v</sub> </em>shows that the material belongs to the soft material category. Preliminary measurement using Kurtz powder technique with Nd-YAG laser light of wavelength 1064 nm indicates that their second harmonic generation (SHG) efficiencies of the grown crystals were presented 2 times in comparison with Potassium Dihydrogen Phosphate (KDP) was confirmed.展开更多
In order to control the grain size during hot forming,grain growth behavior of a pre-extruded Mg-6Zn magnesium alloy and its correlation with solute and second phase distribution were investigated.Isothermal annealing...In order to control the grain size during hot forming,grain growth behavior of a pre-extruded Mg-6Zn magnesium alloy and its correlation with solute and second phase distribution were investigated.Isothermal annealing was conducted on a Gleeble-1500 thermo-mechanical simulator.The mean grain size Dg of each annealed specimen was measured by the quantitative metallography technique.The grain growth kinetics of the Mg-6Zn alloy annealed at 473-623 K was obtained as Dg^4- Dg0^4=2.25 ×10^11 exp（-95450）by the least square linear regression method.The deviation of grain growth exponent n = 4 from the theoretical value of 2 may be attributed to the presence of solute zinc and second phases which will retard the boundary migration.Microscopic observations show that the non-uniform distribution of grain size for samples pre-extruded or annealed at low temperatures is closely related to the non-uniform distribution of fine and dispersed second phases but not to the non-uniform distribution of solute zinc.This indicates that second phase pinning effect plays an important role in microstructure refinement.展开更多
Materials with large non-linear optical properties are good candidates for applications in the fields of telecommunications, solar energy conversion, laser treatment and so on. In the present study, a crystal of Ammon...Materials with large non-linear optical properties are good candidates for applications in the fields of telecommunications, solar energy conversion, laser treatment and so on. In the present study, a crystal of Ammonium Dihydrogen Orthophosphate doped with Acridine Orange, possessing excellent nonlinear optical properties were grown by the slow solvent evaporation technique at 25°C using a constant temperature bath. Ammonium dihydrogen orthophosphate doped with Acridine Orange were synthesized in a large quantity via solution growth method using aqueous mixtures of Ammonium Dihydrogen Orthophosphate and Acridine Orange. The morphological characteristics were studied by field emission scanning electron microscopy which revealed that the synthesized product possesses needle shaped microstructures. The mechanical properties are studied by Vicker’s micro hardness test.展开更多
This paper presents an approach to synthesis of gold nanoparticles with different morphologies and investigation of the relationship between morphologies and their optical properties.Spherical gold nanoparticles with ...This paper presents an approach to synthesis of gold nanoparticles with different morphologies and investigation of the relationship between morphologies and their optical properties.Spherical gold nanoparticles with different sizes are synthesized via reduction method.Using seed-mediated solution growth method,gold nanoparticles with shuttle,star and stick shapes can be obtained.The sizes and morphologies of the gold nanoparticles are characterized by transmission electron microscopy （TEM）.The characterization results illustrate the growth process of the gold nanoparticles with different morphologies.Absorption spectroscopy and Raman spectroscopy measurements are performed to demonstrate the relationship between the morphologies and optical properties.The results of Raman characterization show that the gold nanoparticles with different morphologies can be used to probe molecules with different concentrations.展开更多
基金supported by the Beijing Municipal Science and Technology Commission Project(Z211100004821004)the National Natural Science Foundation of China(51872028)。
文摘The carbon dissolution in solvent plays a key role in the process of solution growth route for SiC single crystal,which could determine the growth rate and quality of the products.However,the carbon dissolving ability of binary alloy solvent still needs to be improved.Here,we demonstrate the improved carbon dissolution and enlarged carbon supersaturation in Cr-Ce-Si ternary solvent,showing great potential for SiC solution growth.The phase relations of Cr-Ce-Si-C system were determined by using CALPHAD method based on thermodynamic parameters of CeCr_(2)Si_(2)C.It is indicated that the Cr-Ce-Si ternary solvent shows much larger carbon solubility in temperature range from 1700 to 2000℃compared to Cr-Si binary one,Furthermore,the carbon supersaturation in solvent is also significantly increased in low temperature range after the addition of Ce,leading to a rapid growth rate.Our work not only demonstrates the feasibility of adding Ce in the alloy solvent for rapid growth of SiC crystal,but also provides an example for investigating the C solubility in ternary solvent.
基金supported by the National Natural Science Foundation of China(Grant No.52302007,52327801,51906086)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20210762).
文摘Spontaneous nucleation of SiC particles and giant macroscopic steps result in the surface roughness of the grown crystal for the top-seeded solution growth of SiC crystal.To suppress the surface roughness,the temperature gradient was carefully adjusted by changing the relative position of the crucible and induction coils.The numerical simulation and experimental results show that the surface morphology of the grown crystal becomes smoother and there are fewer spontaneous nucleation particles attached to the growth surface with the decrease in the relative crucible position,due to the increase of temperature at the entire solution surface and the reducing of temperature gradient near the growth surface.Accordingly,a lower temperature gradient,a larger solution velocity,a higher carbon concentration,and a smaller carbon supersaturation near the growth surface can be obtained when the relative position between the crucible and the induction coil is 70 mm,which is demonstrated to be the most favorable for the elimination of spontaneous nucleation of small SiC particles and suppressing surface roughening with the full width at half maximum(FWHM)of 37.5 arcsec of 4Hsingle bondSiC crystals.
文摘One-dimensional （1D） ZnO nanostructures have been studied intensively and extensively over the last decade not only for their remarkable chemical and physical properties, but also for their diverse current and future technological applications. This article gives a comprehensive overview of the progress that has been made within the context of 1D ZnO nanostructures synthesized via wet chemical methods. We will cover the synthetic methodologies and the corresponding growth mechanisms, various nanostructures grown, their doping and alloying, and position-controlled growth on substrates. Finally, we will review their functional properties in catalysis, hydrophobic surface modification, sensing, and electronic, optical, optoelectronic, and energy harvesting devices.
基金Project supported by the German Research Foundation(DFG)(No.BO 1129/5-1)
文摘The growth of polycrystalline silicon layers on glass from tin solutions at low temperatures is presented.This approach is based on the steady-state solution growth of Si crystallites on nanocrystalline seed layers, which are prepared in a preceding process step. Scanning electron microscopy and atomic force microscopy investigations reveal details about the seed layer surfaces, which consist of small hillocks, as well as about Sn inclusions and gaps along the glass substrate after solution growth. The successful growth of continuous microcrystalline Si layers with grain sizes up to several ten micrometers shows the feasibility of the process and makes it interesting for photovoltaics.
文摘The stability of the shapes of crystal growth face and dissolution face in a two-dimensional mathematical model of crystal growth from solution under microgravity is studied. It is proved that the stable shapes of crystal growth face and dissolution face do exist, which are suitably shaped curves with their upper parts inclined backward properly.The stable shapes of crystal growth faces and dissolution faces are calculated for various values of parameters, Ra, Pr and Sc. It is shown that the stronger the convection relative to the diffusion in solution is, the more backward the upperparts of the stable crystal growth face and dissolution face are inclined. The orientation and the shape of dissolution face hardly affect the stable shape of crystal growth face and vice versa.
文摘In this paper we give a priori estimates for the maximum modulus of generalizedsolulions of the quasilinear elliplic equations irith anisotropic growth condition.
基金This work is supported by the Youth Foundation, NSFC.
文摘In this paper, we get the existence result of the nontrivial weak solution (λ, u) of the following eigenvalue problem with natural growth conditions.
基金Project supported by Jilin Provincial Department of Education(JJKH20230821KJ,JJKH20230822KJ,JJKH20230823KJ,JJKH20240930KJ,20240101107JC)。
文摘The 1.55μm laser technology is widely applied in military,information communication,biomedicine and other fields.With the deepening development of these application areas,the demand for novel 1.55μm laser gain media is becoming increasingly urgent.This study reports a novel Yb^(3+),Er^(3+)co-doped KBa_(0.94)Ca_(0.06)Y(MoO_(4))_(3) (KBCYM)crystal.In this crystal,Yb^(3+)serves as a sensitizer,significantly enhancing the emission intensity of Er^(3+)in both visible and near-infrared bands.Notably,when the concentration of Yb^(3+)reaches 6 mol%,the emission intensity peaks at 1.55μm.Optical cross-section calculations reveal that the crystal exhibits a low laser pumping threshold at this concentration,demonstrating its potential as a laser gain medium.However,the crystal inevitably generates thermal effects during operation,which may adversely affect its performance.Therefore,real-time monitoring of the operating temperature is crucial.The thermal stability of the crystal was evaluated by measuring the temperature dependence of its luminescence intensity in the near-infrared band.Remarkably,even when the temperature rises to 553 K,the emission intensity at 1.55μm only decreases by 10.9%.Additionally,the temperature sensing performance was evaluated using fluorescence intensity ratio techniques,yielding absolute and relative sensitivities of 0.00981 K^(-1)at 453 K and 1.32%/K at 303 K,respectively,highlighting its potential for optical temperature sensing.Finally,through leveraging the unique properties of Yb^(3+),Er^(3+):KBCYM crystals,we successfully developed 1.55μm luminescent optical devices with practical applications.These devices not only exhibit efficient luminescent performance,but also possess a self-temperature measu rement functio n,opening up new avenues for the further development of laser technology.
基金Project supported by Natural Science Foundation of Shandong Province (ZR2011EMM010)the Innovation Foundation of Shandong University
文摘KTb（WO4）2（KTW） single crystal with dimensions up to 30 mm×30 mm 10 mm was grown by the top-seeded solution growth （TSSG） method for the first time. The crystal structure was refined at room temperature by using single crystal X-ray diffiaction data. Ab- sorption and fluorescence spectra were measured at room temperature. The fluorescence lifetime of KTb（WO4）2 was 114 μs. The specific heat of the KTh（WO4）2 crystal was also measured at room temperature.
基金supported by the Foundation for Key Project of Ministry of Education, China (No. 211046)Open Fund of State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Dong Hua University (No. K1012)+1 种基金Open Fund State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University (No. 201222)Program for New Century Excellent Talents in Heilongjiang Provincial University
文摘In this work, flowerlike ZnO micro/nanostructures assembled from nanorods are obtained through a facile hydrothermal route. The experimental results indicated that the as-synthesized ZnO microflowers have an average diameter of 2 μm, composed of nanorods of an average diameter of 200 nm and a tapered morphology.ZnO with other morphologies were also obtained by varying the reaction conditions. Systematical conditiondependent experiments were conducted to reveal the growth mechansim of the microflowers. It is suggested that the zinc source types, solution p H value, and reaction temperature, as well as reaction time are responsible for the variations of ZnO morphology. Luminescence properties of ZnO microflowers were investigated through monitoring different parts of nanorods, showing good optical quality.
文摘A facile one-step method was developed for the fabrication of hierarchical ZnO film on substrate. Neither seed nor catalyst layer is necessary for the growth of hierarchical ZnO film. Three kinds of nucleation process were found, and the influences of growth time, growth electrolyte, growth temperature on the morphology of ZnO film were evaluated. Hierarchical ZnO film can absorb more than 97% of incident photons with wavelength shorter than 380 nm. Such hierarchical ZnO film would be a promising scaffold for photoelectrochemical application.
基金Supported by the NNSFC (No.61275177)the NSF of Fujian Province (No.2012I0011)
文摘The phase diagram, growth and optical property of LaBWO6 crystal are reported. LaBWO6 crystal melts congruently at 1078 ℃. Based on the pseudo-ternary phase diagram of LaBWO6-（Li2WO4/LiF） -B203, the LaBWO6 crystals have been firstly grown by the flux method. LaBWO6 crystal crystallizes in the orthorhombic system, space group P222 with a = 4.1, b = 10.31 and c = 21.71 A. LaBWO6 Crystal exhibits high transparency in a range from 327 to 1100 nm. The absorption edge of the crystal in the UV range is at 293 nm. The SHG efficient of LaBWO6 crystal is 0.3 times as large as that of the KDP crystal.
文摘For a continuous, increasing function ω ： R^＋ →R^＋／{0} of finite exponential type, this paper introduces the set Z（A, ω） of all x in a Banach space X for which the second order abstract differential equation （2） has a mild solution such that [ω（t）]^-1u（t,x） is uniformly continues on R^＋, and show that Z（A, ω） is a maximal Banach subspace continuously embedded in X, where A ∈ B（X） is closed. Moreover, A[z（A,ω） generates an O（ω（t）） strongly continuous cosine operator function family.
文摘The method that we can choose is only the more complicated flux growth techniqUe.A broad range of fluxes which contain B_(2)O_(3),PbO_(2),PbF_(2)and alkali halides etc.have been therefore attemped in our lab、in order to grow large high quality LBO crystals.Most of them seems infavorable to the growth of LBO crystals,and PbO and PbF_(2)also have to be excluded from our considerations although these additives can reduce the viscosity of the growth solution and enhance growth rate,since Pb^(2+)ion can easily enter into the crystal lat-tice and may cause the shatter of crystal thereby.
基金supported by the Beijing Municipal Science and Technology Project(Grant No.Z211100004821004)the Special Project on Transfer and Conversion of Scientific and Technological Achievements of the Chinese Academy of Sciences(Grant No.KFJ-HGZX-042)
文摘Cubic silicon carbide(3C-SiC)has superior mobility and thermal conduction over that of widely applied hexagonal 4H-SiC.Moreover,much lower concentration of interfacial traps between insulating oxide gate and 3C-SiC helps fabricate reliable and long-life devices like metal-oxidesemiconductor field effect transistors.However,the growth of high-quality and wafer-scale 3C-SiC crystals has remained a big challenge up to now despite decades-long efforts by researchers because of its easy transformation into other polytypes during growth,limiting the development of 3C-SiC-based devices.Herein,we report that 3C-SiC can be made thermodynamically favored from nucleation to growth on a 4H-SiC substrate by top-seeded solution growth technique,beyond what is expected by classical nucleation theory.This enables the steady growth of high-quality and large-size 3C-SiC crystals(2-4-inch in diameter and 4.0-10.0 mm in thickness)sustainable.The as-grown 3C-SiC crystals are free of other polytypes and have high-crystalline quality.Our findings broaden the mechanism of hetero-seed crystal growth and provide a feasible route to mass production of 3C-SiC crystals,offering new opportunities to develop power electronic devices potentially with better performances than those based on 4H-SiC.
文摘Sodium acid phthalate C<sub>8</sub>H<sub>5</sub>NaO<sub>4</sub> is one of the suitable semiorganic single crystals hired in second harmonic generation conversion applications. In the present work, optically transparent Benzophenone doped with sodium acid phthalate (SAPB) single crystals were grown successfully by slow evaporation solution technique. Single crystal XRD analyses exposed that the crystal lattice of SAPB crystal is a monoclinic crystal system with unit cell parameters <em>a</em> = 6.77 <span style="white-space:nowrap;"><span style="white-space:nowrap;"><span class="color-dim" style="box-sizing:border-box;color:#636363;font-family:Montserrat, system-ui, -apple-system, BlinkMacSystemFont, "font-size:40px;text-align:center;white-space:normal;background-color:#FFFFFF;"><span style="white-space:nowrap;">Å</span></span><span class="color-dim" style="box-sizing:border-box;color:#636363;font-family:Montserrat, system-ui, -apple-system, BlinkMacSystemFont, "font-size:40px;text-align:center;white-space:normal;background-color:#FFFFFF;"></span></span></span>, <em>b </em>= 9.31 <span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">Å</span></span></span>, <em>c</em> = 13.58 <span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">Å</span></span></span>, and space group B2cb. The crystalline nature of SAPB material was confirmed by powder XRD pattern. The functional groups present in the grown crystals were identified by the FTIR analysis ranging between 4000 and 500 cm<sup><span style="white-space:nowrap;"><span class="color-dim" style="box-sizing:border-box;color:#636363;font-family:Montserrat, system-ui, -apple-system, BlinkMacSystemFont, " font-size:40px;text-align:center;white-space:normal;background-color:#ffffff;"=""><span style="white-space:nowrap;">−</span></span><span class="color-dim" style="box-sizing:border-box;color:#636363;font-family:Montserrat, system-ui, -apple-system, BlinkMacSystemFont, " font-size:40px;text-align:center;white-space:normal;background-color:#ffffff;"=""></span></span>1</sup>. The optical transparency and band gap of grown crystals were measured from UV-Visible spectroscopy. The fluorescence emission spectrum of the SAPB crystal having a strong Yellow emission peak at 574 nm and the red emission at 631 nm are identified. The Vickers microhardness number (<em>H<sub>v</sub></em>) increases with increasing load. Meyer’s index number (<em>n</em>) calculated from <em>H<sub>v</sub> </em>shows that the material belongs to the soft material category. Preliminary measurement using Kurtz powder technique with Nd-YAG laser light of wavelength 1064 nm indicates that their second harmonic generation (SHG) efficiencies of the grown crystals were presented 2 times in comparison with Potassium Dihydrogen Phosphate (KDP) was confirmed.
基金the financial support from the National Natural Science Foundation of China(Grant No.51105328)the Natural Science Foundation of Jiangsu Province of China(No.BK20130447)the Colleges and Universities in Jiangsu Province Natural Science Foundation of China(Grant No.13KJB430026)
文摘In order to control the grain size during hot forming,grain growth behavior of a pre-extruded Mg-6Zn magnesium alloy and its correlation with solute and second phase distribution were investigated.Isothermal annealing was conducted on a Gleeble-1500 thermo-mechanical simulator.The mean grain size Dg of each annealed specimen was measured by the quantitative metallography technique.The grain growth kinetics of the Mg-6Zn alloy annealed at 473-623 K was obtained as Dg^4- Dg0^4=2.25 ×10^11 exp（-95450）by the least square linear regression method.The deviation of grain growth exponent n = 4 from the theoretical value of 2 may be attributed to the presence of solute zinc and second phases which will retard the boundary migration.Microscopic observations show that the non-uniform distribution of grain size for samples pre-extruded or annealed at low temperatures is closely related to the non-uniform distribution of fine and dispersed second phases but not to the non-uniform distribution of solute zinc.This indicates that second phase pinning effect plays an important role in microstructure refinement.
文摘Materials with large non-linear optical properties are good candidates for applications in the fields of telecommunications, solar energy conversion, laser treatment and so on. In the present study, a crystal of Ammonium Dihydrogen Orthophosphate doped with Acridine Orange, possessing excellent nonlinear optical properties were grown by the slow solvent evaporation technique at 25°C using a constant temperature bath. Ammonium dihydrogen orthophosphate doped with Acridine Orange were synthesized in a large quantity via solution growth method using aqueous mixtures of Ammonium Dihydrogen Orthophosphate and Acridine Orange. The morphological characteristics were studied by field emission scanning electron microscopy which revealed that the synthesized product possesses needle shaped microstructures. The mechanical properties are studied by Vicker’s micro hardness test.
基金Merit-funded Science and Technology Project for Returned Oversea Scholars from Ministry of Human and Social Security of Shanxi provinceNatural Science Foundation for Young Scientists of Shanxi province(No.2011011020-2)Shanxi Province Foundation for Returness(No.2008062)
文摘This paper presents an approach to synthesis of gold nanoparticles with different morphologies and investigation of the relationship between morphologies and their optical properties.Spherical gold nanoparticles with different sizes are synthesized via reduction method.Using seed-mediated solution growth method,gold nanoparticles with shuttle,star and stick shapes can be obtained.The sizes and morphologies of the gold nanoparticles are characterized by transmission electron microscopy （TEM）.The characterization results illustrate the growth process of the gold nanoparticles with different morphologies.Absorption spectroscopy and Raman spectroscopy measurements are performed to demonstrate the relationship between the morphologies and optical properties.The results of Raman characterization show that the gold nanoparticles with different morphologies can be used to probe molecules with different concentrations.
