p-Type nano-ZnFe2O4 semiconductors were gained by high-prssure treatment.Surface photovoltaic spectrum（SPS） and transient photovoltaic technology（TPV） were used for studying the photogenerated charge of nano-ZnFe2...p-Type nano-ZnFe2O4 semiconductors were gained by high-prssure treatment.Surface photovoltaic spectrum（SPS） and transient photovoltaic technology（TPV） were used for studying the photogenerated charge of nano-ZnFe2O4.Results show that the photovoltaic behavior of nano-ZnFe2O4 changed as the processing pressure increased.When the processing pressure was higher than 2 GPa,both SPS response interval and peak changed significantly.XPS results show that the non-lattice oxygen entered into the lattice and the content of lattice oxygen increased with the increase of processing pressure.The material changed from oxygen vacancy type to oxygen excess type and the photoelectric properties changed from n-type to p-type when the processing pressure is higher than 2 GPa.展开更多
The mutant strains of aspergillus oryzae （HP300a） are screened under 300 MPa for 20min. Compared with the control strains, the screened mutant strains have unique properties such as genetic stability, rapid growth, ...The mutant strains of aspergillus oryzae （HP300a） are screened under 300 MPa for 20min. Compared with the control strains, the screened mutant strains have unique properties such as genetic stability, rapid growth, lots of spores, and high protease activity. Random amplified polymorphic DNA （RAPD） and inter simple sequence repeats （ISSR） are used to analyze the DNA fingerprinting of HP300a and the control strains. There are 67.9% and 51.3% polymorphic bands obtained by these two markers, respectively, indicating significant genetic variations between HP300a and the control strains. In addition, comparison of HP300a arid the control strains, the genetic distances of random sequence and simple sequence repeat of DNA are 0.51 and 0.34, respectively.展开更多
Diamond films were synthesized on Si substrate by electron-assisted chemical vapor deposition method using gas mixtures of methane(or acetone)and hydrogen.Various crystal structures of diamond films were obtained by s...Diamond films were synthesized on Si substrate by electron-assisted chemical vapor deposition method using gas mixtures of methane(or acetone)and hydrogen.Various crystal structures of diamond films were obtained by synthesis with various deposition conditions.The influences of various deposition conditions on thermal conductivity of diamond film were studied.The results show that large-grain(100)-oriented diamond films synthesized at lower concentration of methane and acetone have higher thermal conductivity,and thermal conductivity increases with the increasing in film thickness and the removal of the Sic layer on the back of the film,at last,annealing in ambience of hydrogen is advantageous to acquiring diamond film with high thermal conductivity.展开更多
We report a cubic boron nitride(c-BN)film with low stress.Infrared(IR)peak position of c-BN at 1006.3cm-1measured by IR spectroscopy shows that the c-BN film has very low internal stress which leads to an excellent ad...We report a cubic boron nitride(c-BN)film with low stress.Infrared(IR)peak position of c-BN at 1006.3cm-1measured by IR spectroscopy shows that the c-BN film has very low internal stress which leads to an excellent adhesion.Transmission electron microscope micrograph indicates the only BN phase on the surface of the film is c-BN phase.It is clearly seen from IR spectra that the intermediate layer between the substrate and the c-BN layer is of the molecular crystal explosion boron nitride,hexagonal boron nitride,and wurtzic boron nitride.展开更多
Ta/anodized Ta_(2)O_(5) /Al is used as metal-insulator-metal (MIM) element in experiments, The current- voltage (I- V) characteristic of the MIM element depends on the chamber pressure in heat-treating anodized Ta2O5 ...Ta/anodized Ta_(2)O_(5) /Al is used as metal-insulator-metal (MIM) element in experiments, The current- voltage (I- V) characteristic of the MIM element depends on the chamber pressure in heat-treating anodized Ta2O5 film. Good nonlinear I- V characteristic has been obtained in the pressure range from 10^(-2) to 10^(-4) to Torr. Meanwhile, the conductivity coefficient α of the Poole-frenkel (PF) equation which describes the I- V characteristic can be regulated by about two orders of magnitude in this pressure range, while the non-linearity coefficient β of the PF equation is not affected by the chamber pressure.展开更多
In this work,it is found that the compressive stress on the surface of cubic-BN(c-BN)film is all smaller than that inside c-BN film and after a longer period,the depositing matter mainly is of hexagonal-BN phase rathe...In this work,it is found that the compressive stress on the surface of cubic-BN(c-BN)film is all smaller than that inside c-BN film and after a longer period,the depositing matter mainly is of hexagonal-BN phase rather than c-BN phase,those just are the reason why a pure thicker c-BN film cannot,as yet,be obtained.Up to now the lowest IR peak position of 1004.7cm-1 detected from a broken and part delaminated c-BN film may be one close to the stressless c-BN.展开更多
Within a movable and orientable rigid rotor model,four interaction potentials of solid deuterium(hydrogen)system from combinations of two isotropic and two anistropic parts are tested by the path integral Monte Carlo ...Within a movable and orientable rigid rotor model,four interaction potentials of solid deuterium(hydrogen)system from combinations of two isotropic and two anistropic parts are tested by the path integral Monte Carlo method in a constant-pressure ensemble.With the best one of the potentials,the equation of state of deuterium is quantitatively in agreement with the experimental data.For understanding the quantum nature of the solid,the energies of the system at different temperatures are also calculated,the results show strong zero-point motions exist in the solid.As would be expected,the quantum corrections to both the rotational and the translational kinetic energies decrease with increasing temperature,and increase with pressure.展开更多
The Raman scattering in Zn_(0.74)Cd_(0.26)Se/ZnSe superlattices under hydrostatic pressures up to 4.53 GPa at room temperature has been studied.The pressure-dependences of the ZnSe-like LO-phonon(LO_(b))and the Zn_(0....The Raman scattering in Zn_(0.74)Cd_(0.26)Se/ZnSe superlattices under hydrostatic pressures up to 4.53 GPa at room temperature has been studied.The pressure-dependences of the ZnSe-like LO-phonon(LO_(b))and the Zn_(0.74)Cd_(0.26)Se-like LO-phonon(LO_(w))have been obtained.At 2.7GPa,the pressure-coefficients of both LO_(b) and LO_(w) phonon energies increase abruptly The 2LO_(w)-phonon resonance has been observed at 1.82GPa with 488.0nm excitation for the Zn_(0.75)Cd_(0.25)Se/ZnSe superlattices.展开更多
Diamond films of various thickness(1-300μm)were deposited on single-crystal Si active(300μm)by a microwave plasma chemical vapor deposition method using gaseous mixtures of methane and hydrogen.After thinning of the...Diamond films of various thickness(1-300μm)were deposited on single-crystal Si active(300μm)by a microwave plasma chemical vapor deposition method using gaseous mixtures of methane and hydrogen.After thinning of the Si layer by machine and ion-beam polishing a diamond-based silicon-on-insulator structure with final Si layer thickness of about 1μm is formed.Thermal conductivity of this structure material with various thicknesses of diamond and Si layer was measured.Compared with bulk silicon,the thermal conductivity of the siliconon-diamond structure with 300μm diamond and 1μm silicon increases by 850%.展开更多
Gallium nitride crystals in nano-scale have been fabricated by dc arc plasma method using gallium and N_(2)+NH_(3) as starting materials.Transmission electron microscope,selected area diffraction and x-ray diffraction...Gallium nitride crystals in nano-scale have been fabricated by dc arc plasma method using gallium and N_(2)+NH_(3) as starting materials.Transmission electron microscope,selected area diffraction and x-ray diffraction investigation of the as-grown GaN crystals show that the well faceted crystals are single crystalline GaN in wurtzite structure having lattice constants a_(0)=3.18Åand c_(0)=5.18Å.展开更多
High quality diamond epitaxial film has been obtained on high pressure synthesized cubic boron nitride crystal surface by dc glow discharge chemical vapor deposition. The growth characteristics of the epitaxial film h...High quality diamond epitaxial film has been obtained on high pressure synthesized cubic boron nitride crystal surface by dc glow discharge chemical vapor deposition. The growth characteristics of the epitaxial film have been investigated by scanning electron microscope. The quality of the film has been confirmed by Raman spectroscope to be close to that of natural diamond.展开更多
Raman spectra of layered ferroelectrics Ba_(2+x)Bi_(4-x)Ti_(5-x)Nb_(x)O_(18)(0≤x≤2)at room temperature in the range 20-1000cm^(-1) were investigated.Vibration modes were assigned with the use of internal mode approa...Raman spectra of layered ferroelectrics Ba_(2+x)Bi_(4-x)Ti_(5-x)Nb_(x)O_(18)(0≤x≤2)at room temperature in the range 20-1000cm^(-1) were investigated.Vibration modes were assigned with the use of internal mode approach.Two doping-induced structure phase transitions were observed at about x=0.50 and x=1.25,respectively.Raman spectra variations were analyzed according to the selection rules of BO_(6) octahedra in various symmetry.Polycrystalline samples were synthesized by solid state reaction method.展开更多
Raman spectra of layered ferroelectrics Sr_(2+x)Bi_(4-x)Ti_(5-x)Nb_(x)O_(18)(0≤x≤2)and Sr_(2)Bi_(4-x)La_(x)Ti_(5)O_(18)at room temperature in the range of 20-1000 cm^(-1)were investigated.Vibration modes were assign...Raman spectra of layered ferroelectrics Sr_(2+x)Bi_(4-x)Ti_(5-x)Nb_(x)O_(18)(0≤x≤2)and Sr_(2)Bi_(4-x)La_(x)Ti_(5)O_(18)at room temperature in the range of 20-1000 cm^(-1)were investigated.Vibration modes were assigned with the interna.1 mode approach.Two doping-induced structure phase transitions were observed at about x=0.5 and 1.25 for Sr_(2+x)Bi_(4-x)Ti_(5-x)Nb_(x)O_(18),separately.展开更多
基金Supported by the National Natural Science Foundation of China(No.20803031)the Specialized Research Fund for Basic Research and Operating Expenses of Jilin University,China(No.200903327)+1 种基金the National Fund for Fostering Talents of Basic Science,China(No.J1103202)the Open Topic of State Key Laboratory of Superhard Materials,China(No.200904)
文摘p-Type nano-ZnFe2O4 semiconductors were gained by high-prssure treatment.Surface photovoltaic spectrum（SPS） and transient photovoltaic technology（TPV） were used for studying the photogenerated charge of nano-ZnFe2O4.Results show that the photovoltaic behavior of nano-ZnFe2O4 changed as the processing pressure increased.When the processing pressure was higher than 2 GPa,both SPS response interval and peak changed significantly.XPS results show that the non-lattice oxygen entered into the lattice and the content of lattice oxygen increased with the increase of processing pressure.The material changed from oxygen vacancy type to oxygen excess type and the photoelectric properties changed from n-type to p-type when the processing pressure is higher than 2 GPa.
基金Supported by the National Natural Science Foundation of China under Grant Nos 20773043, 21073071 and 10979001, and the National Basic Research Program of China under Grant Nos 2005CB724400 and 2007CB808000.
文摘The mutant strains of aspergillus oryzae （HP300a） are screened under 300 MPa for 20min. Compared with the control strains, the screened mutant strains have unique properties such as genetic stability, rapid growth, lots of spores, and high protease activity. Random amplified polymorphic DNA （RAPD） and inter simple sequence repeats （ISSR） are used to analyze the DNA fingerprinting of HP300a and the control strains. There are 67.9% and 51.3% polymorphic bands obtained by these two markers, respectively, indicating significant genetic variations between HP300a and the control strains. In addition, comparison of HP300a arid the control strains, the genetic distances of random sequence and simple sequence repeat of DNA are 0.51 and 0.34, respectively.
文摘Diamond films were synthesized on Si substrate by electron-assisted chemical vapor deposition method using gas mixtures of methane(or acetone)and hydrogen.Various crystal structures of diamond films were obtained by synthesis with various deposition conditions.The influences of various deposition conditions on thermal conductivity of diamond film were studied.The results show that large-grain(100)-oriented diamond films synthesized at lower concentration of methane and acetone have higher thermal conductivity,and thermal conductivity increases with the increasing in film thickness and the removal of the Sic layer on the back of the film,at last,annealing in ambience of hydrogen is advantageous to acquiring diamond film with high thermal conductivity.
基金Supported by the National Natural Science Foundation of China under Grant Nos.59831040 and 19774025the Jilin Province Science and Technology Foundation.
文摘We report a cubic boron nitride(c-BN)film with low stress.Infrared(IR)peak position of c-BN at 1006.3cm-1measured by IR spectroscopy shows that the c-BN film has very low internal stress which leads to an excellent adhesion.Transmission electron microscope micrograph indicates the only BN phase on the surface of the film is c-BN phase.It is clearly seen from IR spectra that the intermediate layer between the substrate and the c-BN layer is of the molecular crystal explosion boron nitride,hexagonal boron nitride,and wurtzic boron nitride.
基金the National Natural Science Foundation of China under Grant Nos.69576012 and 59631060.
文摘Ta/anodized Ta_(2)O_(5) /Al is used as metal-insulator-metal (MIM) element in experiments, The current- voltage (I- V) characteristic of the MIM element depends on the chamber pressure in heat-treating anodized Ta2O5 film. Good nonlinear I- V characteristic has been obtained in the pressure range from 10^(-2) to 10^(-4) to Torr. Meanwhile, the conductivity coefficient α of the Poole-frenkel (PF) equation which describes the I- V characteristic can be regulated by about two orders of magnitude in this pressure range, while the non-linearity coefficient β of the PF equation is not affected by the chamber pressure.
基金Supported by the National Natural Science Foundation of China under Grant No.19774025Jilin Province Science and Technology Foundation.
文摘In this work,it is found that the compressive stress on the surface of cubic-BN(c-BN)film is all smaller than that inside c-BN film and after a longer period,the depositing matter mainly is of hexagonal-BN phase rather than c-BN phase,those just are the reason why a pure thicker c-BN film cannot,as yet,be obtained.Up to now the lowest IR peak position of 1004.7cm-1 detected from a broken and part delaminated c-BN film may be one close to the stressless c-BN.
基金Supported in part by the National Natural Science Foundation of China under Grant No.19484002.
文摘Within a movable and orientable rigid rotor model,four interaction potentials of solid deuterium(hydrogen)system from combinations of two isotropic and two anistropic parts are tested by the path integral Monte Carlo method in a constant-pressure ensemble.With the best one of the potentials,the equation of state of deuterium is quantitatively in agreement with the experimental data.For understanding the quantum nature of the solid,the energies of the system at different temperatures are also calculated,the results show strong zero-point motions exist in the solid.As would be expected,the quantum corrections to both the rotational and the translational kinetic energies decrease with increasing temperature,and increase with pressure.
文摘The Raman scattering in Zn_(0.74)Cd_(0.26)Se/ZnSe superlattices under hydrostatic pressures up to 4.53 GPa at room temperature has been studied.The pressure-dependences of the ZnSe-like LO-phonon(LO_(b))and the Zn_(0.74)Cd_(0.26)Se-like LO-phonon(LO_(w))have been obtained.At 2.7GPa,the pressure-coefficients of both LO_(b) and LO_(w) phonon energies increase abruptly The 2LO_(w)-phonon resonance has been observed at 1.82GPa with 488.0nm excitation for the Zn_(0.75)Cd_(0.25)Se/ZnSe superlattices.
文摘Diamond films of various thickness(1-300μm)were deposited on single-crystal Si active(300μm)by a microwave plasma chemical vapor deposition method using gaseous mixtures of methane and hydrogen.After thinning of the Si layer by machine and ion-beam polishing a diamond-based silicon-on-insulator structure with final Si layer thickness of about 1μm is formed.Thermal conductivity of this structure material with various thicknesses of diamond and Si layer was measured.Compared with bulk silicon,the thermal conductivity of the siliconon-diamond structure with 300μm diamond and 1μm silicon increases by 850%.
文摘Gallium nitride crystals in nano-scale have been fabricated by dc arc plasma method using gallium and N_(2)+NH_(3) as starting materials.Transmission electron microscope,selected area diffraction and x-ray diffraction investigation of the as-grown GaN crystals show that the well faceted crystals are single crystalline GaN in wurtzite structure having lattice constants a_(0)=3.18Åand c_(0)=5.18Å.
基金the National Natural Science Foundation of China under Grant No.59572036.
文摘High quality diamond epitaxial film has been obtained on high pressure synthesized cubic boron nitride crystal surface by dc glow discharge chemical vapor deposition. The growth characteristics of the epitaxial film have been investigated by scanning electron microscope. The quality of the film has been confirmed by Raman spectroscope to be close to that of natural diamond.
基金Supported by the National Doctoral Foundation of the China Education Commission under Grant No.96018307。
文摘Raman spectra of layered ferroelectrics Ba_(2+x)Bi_(4-x)Ti_(5-x)Nb_(x)O_(18)(0≤x≤2)at room temperature in the range 20-1000cm^(-1) were investigated.Vibration modes were assigned with the use of internal mode approach.Two doping-induced structure phase transitions were observed at about x=0.50 and x=1.25,respectively.Raman spectra variations were analyzed according to the selection rules of BO_(6) octahedra in various symmetry.Polycrystalline samples were synthesized by solid state reaction method.
文摘Raman spectra of layered ferroelectrics Sr_(2+x)Bi_(4-x)Ti_(5-x)Nb_(x)O_(18)(0≤x≤2)and Sr_(2)Bi_(4-x)La_(x)Ti_(5)O_(18)at room temperature in the range of 20-1000 cm^(-1)were investigated.Vibration modes were assigned with the interna.1 mode approach.Two doping-induced structure phase transitions were observed at about x=0.5 and 1.25 for Sr_(2+x)Bi_(4-x)Ti_(5-x)Nb_(x)O_(18),separately.
