[Objective] The paper aims to study the relationship between genetic polymorphisms of three gene loci and growth character of Haimen Goats to provide reference to promote Haimen Goat growth character and cultivate Hai...[Objective] The paper aims to study the relationship between genetic polymorphisms of three gene loci and growth character of Haimen Goats to provide reference to promote Haimen Goat growth character and cultivate Haimen Goat new strain of fast-growth.[Method] We processed analysis and related statistical analysis on three gene loci of Haimen Goats with PCR-RFLP and PCR-SSCP.[Result] The results suggested that there were two genotypes in MSTN gene IntronⅡ,GH gene exonⅠ and GH gene exonⅡ in Haimen Goats.Different genotypes of these gene loci had different effects on relative growth character of Haimen Goats.[Conclusion] This study had a significant meaning about promoting Haimen Goat avoirdupois by marker assistant option.展开更多
Anodization of AZ91D magnesium alloy in the electrolyte solution of 0.5 mol/L of sodium silicate and 1.0 mol/L of potassium fluoride was investigated. The anodic films were characterized using optical microscopy （OM...Anodization of AZ91D magnesium alloy in the electrolyte solution of 0.5 mol/L of sodium silicate and 1.0 mol/L of potassium fluoride was investigated. The anodic films were characterized using optical microscopy （OM）, scanning electron microscopy （SEM）, and X-ray diffraction （XRD）. The corrosion resistance of the various anodized alloys was evaluated by a fast corrosion test using the solution of hydrochloric acid and potassium dichromate. The results showed that the addition of KF resulted in the presence of NaF in the anodic film. The thickness of the anodic film formed under a constant current density of 20 mA/cm^2 for 16 rain at 60℃ exceeded 100 gm. The growth of the anodic film could be divided into three stages based on the anodizing time; the growth rate was much faster during stage Ⅱ than in stages I and Ⅲ. The anodic film exhibited the highest corrosion resistance for the AZ91 alloy, which is attributed to the fact that the anodization was maintained until the end of stage Ⅱ.展开更多
The growth character and microstructure of high-T_c supereonducting YBCO thin films deposited on vari- ous substrates have been studied by X-ray diffraction, TEM and SEM.The results show that when the substrate temper...The growth character and microstructure of high-T_c supereonducting YBCO thin films deposited on vari- ous substrates have been studied by X-ray diffraction, TEM and SEM.The results show that when the substrate temperaturc is around 700～800℃ the films have a highly oriented texture with c-axis pependicular to the substrate. The structure of the single crystalline YBCO films grown epitaxially at optimal substrate tem- perature of 800℃ has been established by X-ray diffraction using Seemann-Bohlin geometry (SB). Brentano-Bragg geometry(BB),transmission Laue method and TEM. The lattice matching required for epitaxial growth is achievcd by azimuthal adjustment of the film plane with respect to the substrate plane. The sperior growth is demonstrated by film properties such as critical current density(2.4×10~6 A /cm^2,3.4× 10~6 A/cm^2 and 4.7×l0~6 A/cm^2) for films deposited on YSZ[(Zr(Y)O_2],SrTiO_3 and LaAIO_3 respectively at 77 K and zero fie1d.展开更多
The nanosize grain growth characteristics of spherical single-crystal titanium oxide （TiO2） during the rapid gaseous detonation reaction are discussed. Based on the experimental conditions and the Chapman-Jouguet th...The nanosize grain growth characteristics of spherical single-crystal titanium oxide （TiO2） during the rapid gaseous detonation reaction are discussed. Based on the experimental conditions and the Chapman-Jouguet theory, the Kruis model was introduced to simulate the growth characteristics of spherical TiO2 nanoparticles obtained under high pressure, high temperature and by rapid reaction. The results show that the numerical analysis can satisfactorily predict the growth characteristics of spherical TiO2 nanoparticles with diameters of 15-300 nm at different affecting factors, such as concentration of particles, reaction temperature and time, which are in agreement with the obtained experimental results. We found that the increase of the gas-phase reaction temperature, time, and particle concentration affects the growth tendency of spherical nanocrystal TiO2, which provides effective theoretical support for the controllable synthesis of multi-scale nanoparticles.展开更多
We report on the single crystal growth and superconducting properties of PbTaSe2 with the non-centrosymmetric crystal structure. By using the chemicM vapor transport technique, centimeter-size single crystals are succ...We report on the single crystal growth and superconducting properties of PbTaSe2 with the non-centrosymmetric crystal structure. By using the chemicM vapor transport technique, centimeter-size single crystals are success- fully obtained. The measurement of temperature dependence of electricaJ resistivity p（T） in both normal and superconducting states indicates a quasi-two-dimensional electronic state in contrast to that of polycrystalline samples. Specific heat C（T） measurement reveals a bulk superconductivity with Tc ≈ 3.75K and a specific heat jump ratio of 1.42. All these results are in agreement with a moderately electron-phonon coupled, type-g Bardeen-Cooper-Schrieffer superconductor.展开更多
CaN nanorods are successfully fabricated by adjusting the flow rate ratio of hydrogen （H2）/nitrogen （N2） and growth temperature of the selective area growth （SAG） method with metal organic chemical vapor deposit...CaN nanorods are successfully fabricated by adjusting the flow rate ratio of hydrogen （H2）/nitrogen （N2） and growth temperature of the selective area growth （SAG） method with metal organic chemical vapor deposition （MOCVD）. The SAG template is obtained by nanospherical-lens photolithography. It is found that increasing the flow rate of 1-12 will change the CaN crystal shape from pyramid to vertical rod, while increasing the growth temperature will reduce the diameters of GaN rods to nanometer scale. Finally the CaN nanorods with smooth lateral surface and relatively good quality are obtained under the condition that the H2：N2 ratio is 1：1 and the growth temperature is 1030℃. The good crystal quality and orientation of GaN nanorods are confirmed by high resolution transmission electron microscopy. The cathodoluminescence spectrum suggests that the crystal and optical quality is also improved with increasing the temperature.展开更多
Aiming at searching for plant growth promoting rhizobacteria (PGPR), a bacterium strain coded as 7016 was isolated from soybean rhizosphere and was characterized in the present study. It was identiifed as Burkholderia...Aiming at searching for plant growth promoting rhizobacteria (PGPR), a bacterium strain coded as 7016 was isolated from soybean rhizosphere and was characterized in the present study. It was identiifed as Burkholderia sp. based on 16S rDNA sequence analysis, as wel as phenotypic and biochemical characterizations. This bacterium presented nitrogenase activity, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity and phosphate solubilizing ability;inhibited the growth of Sclerotinia sclerotiorum, Gibberel a zeae and Verticil ium dahliae;and produced smal quantities of indole acetic acid (IAA). In green house experiments, signiifcant increases in shoot height and weight, root length and weight, and stem diameter were observed on tomato plants in 30 d after inoculation with strain 7016. Result of 16S rDNA PCR-DGGE showed that 7016 survived in the rhizosphere of tomato seedlings. In the ifeld experiments, Burkholderia sp. 7016 enhanced the tomato yield and signiifcantly promoted activities of soil urease, phosphatase, sucrase, and catalase. Al these results demonstrated Burkholderia sp. 7016 as a valuable PGPR and a candidate of biofertilizer.展开更多
Large size AlN bulk crystal has been grown on SiC heterogeneous seed by physical vapor transport (PVT). The properties of AlN wafer were characterized by high resolution X-ray diffraction (HRXRD), Raman spectroscopy, ...Large size AlN bulk crystal has been grown on SiC heterogeneous seed by physical vapor transport (PVT). The properties of AlN wafer were characterized by high resolution X-ray diffraction (HRXRD), Raman spectroscopy, etched method and atomic force microscope (AFM). Growth mechanism of AlN crystal grown on heterogeneous SiC seeds was proposed. Crystallization quality of AlN samples were improved with the growth process, which is associated with the growth mechanism. AlN single wafer has excellent crystallization quality, which is indicated by HRXRD showing the (0002),(1012) XRD FWHM of 76.3,52.5 arcsec, respectively. The surface of the AlN wafer is measured by AFM with a roughnessof 0.15 nm, which is a promising seed for AlN homogeneous growth.展开更多
InAs1-xSbx with different compositions is grown by molecular beam epitaxy on （100）-oriented semi-insulating GaAs substrates. The increase of Sb content in the epilayer results in the deterioration of crystal quality...InAs1-xSbx with different compositions is grown by molecular beam epitaxy on （100）-oriented semi-insulating GaAs substrates. The increase of Sb content in the epilayer results in the deterioration of crystal quality and surface morphology. Hall measurements show that the carrier concentration increases with the composition of Sb. The electron mobility decreases initially, when Sb composition exceeds a certain value, and the mobility increases slightly. In this work, we emphasize the comparison of crystal quality, surface morphology and electrical properties of epilayers with different Sb compositions.展开更多
We report the growth of InSb layers directly on GaAs （001） substrates without any buffer layers by molecular beam epitaxy （MBE）. Influences of growth temperature and V/Ⅲ flux ratios on the crystal quality, the su...We report the growth of InSb layers directly on GaAs （001） substrates without any buffer layers by molecular beam epitaxy （MBE）. Influences of growth temperature and V/Ⅲ flux ratios on the crystal quality, the surface morphology and the electrical properties of InSb thin films are investigated. The InSb samples with room- temperature mobility of 44600cm2/Vs are grown under optimized growth conditions. The effect of defects in InSb epitaxial on the electrical properties is researched, and we infer that the formation of In vacancy （VIn） and Sb anti-site （SbIn） defects is the main reason for concentrations changing with growth temperature and Sb2/In flux ratios. The mobility of the InSb sample as a function of temperature ranging from 90 K to 360K is demonstrated and the dislocation scattering mechanism and phonon scattering mechanism are discussed.展开更多
By using Tb407 and MoO3 as starting materials, ferroelectric Tb2（MoO4）3 crystal was grown by the Czochralski method. The as-grown crystal was pale green color, transparent and crack-free. X-ray powder diffraction （...By using Tb407 and MoO3 as starting materials, ferroelectric Tb2（MoO4）3 crystal was grown by the Czochralski method. The as-grown crystal was pale green color, transparent and crack-free. X-ray powder diffraction （XRPD）, transmission spectrum, dielectric constant and polarization-electric field （P-E） hysteresis loop measurements were performed to characterize the crystal. The XRPD confirmed the as-grown crystal to be Tb2（MoO4）3. The transmission spectrum of the crystal showed that its transmittance in the entire visible and most near-infrared region was more than 70% except for an absorption peak around 486 nm. Obvious dielectric anomaly could be observed at low frequencies with increasing temperature through the dielectric constant measurement and the Curie temperature of Tb2（MoO4）3 crystal was determined to be 162.3℃ The unsaturated P-E hysteresis loops indicated that it was difficult for the ferroelectric domains in Tb2（MoO4）3 crystal to array regularly with repeated switching of the electric field.展开更多
A nonlinear optical crystal of gamma glycine was grown by slow evaporation solution growth technique using deionized water and sodium acetate. The functional groups and vibrational frequencies were identified using FT...A nonlinear optical crystal of gamma glycine was grown by slow evaporation solution growth technique using deionized water and sodium acetate. The functional groups and vibrational frequencies were identified using FTIR spectral analysis. The cell parameters were determined from single crystal X-ray diffraction analysis. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were used to study its thermal properties. The optical transmittance window and lower cutoff wavelength have been identified by UV-absorption spectrum analysis. Second harmonic generation (SHG) efficiency measurement was carried out by powder Kurtz method.展开更多
AlxIn1-xAs with 0.47&lex&le0.62 onto (100) oriented InP substrate was grown by molecular beam epitaxy (MBE) and characterized with X-ray double crystal diffraction, low temperature photoluminescence and an ele...AlxIn1-xAs with 0.47&lex&le0.62 onto (100) oriented InP substrate was grown by molecular beam epitaxy (MBE) and characterized with X-ray double crystal diffraction, low temperature photoluminescence and an electron probe. Results show their high qualities. Strain and residual stress were studied in detail.展开更多
Rhizobia are vital for nitrogen input, fertility of soil and legume plant growth. Knowledge on rhizobial diversity from arid and semiarid areas is important for dry land agriculture in the context of climatic change a...Rhizobia are vital for nitrogen input, fertility of soil and legume plant growth. Knowledge on rhizobial diversity from arid and semiarid areas is important for dry land agriculture in the context of climatic change and for economic utilization. This study provides morphological, biochemical, stress tolerance and plant growth promoting characteristics of fifteen rhizobial isolates from the nodules of same number of wild legumes and one isolate from cultivated Arachis hypogea from semi-arid region, Tirupati. The bacterial isolates were confirmed as rhizobia based on colony morphology and biochemical tests. Based on the colour change of YMA-BTB medium, eight isolates were identified as slow growers and six were fast growers. The isolates differed in growth pattern, colony morphology, antibiotic resistance at higher concentrations and uniformity in utilization of carbon and nitrogen sources. The isolates are tolerant to NaCl up to one percent, displayed normal growth at temperatures 28℃ - 30℃, at neutral pH and poor growth at pH 5and 9. The isolates varied in the production of EPS and IAA, positive for phosphate solubilization and siderophore formation. This functional diversity displayed by the isolates can be utilised for the legume crop production by cross inoculation.展开更多
Nonlinear optical single crystals of Ethylene Diamine Tetra Acetate (EDTA) doped lithium sulphate monohydrate are successfully grown by using slow evaporation technique at room temperature with double distilled water ...Nonlinear optical single crystals of Ethylene Diamine Tetra Acetate (EDTA) doped lithium sulphate monohydrate are successfully grown by using slow evaporation technique at room temperature with double distilled water as solvent. In order to know its suitability for device fabrication, different characterization analyses have been performed. The single crystal X-ray diffraction (XRD) and powder X-ray diffraction methods are used for identifying the structural parameters of grown crystals. It is found that the addition of dopant doesn’t change the crystal structure. The range and percentage of optical transmission as well as absorption are ascertained by recording UV-Vis-NIR spectrum. No absorption in the entire visible region implies that it is a potential candidate for optoelectronic applications. The modes of vibration of different groups present in the crystals are identified by FT-IR technique. To understand the thermal properties, thermo gravimetric and differential thermal analyses (TGA & DTA) were carried out. The melting point was confirmed by differential scanning calorimetric (DSC) analysis. The amount of dopant included into the crystals was estimated by colorimetric method. The second harmonic generation efficiency measured by Kurtz powder technique is 0.53 times that of potassium dihydrogen orthophosphate.展开更多
Bis L-alanine Triethanol amine (BLATEA) salt was synthesized by solution method and it was subjected to solubility studies. Using the solubility data, the saturated solution of the synthesized salt was prepared and si...Bis L-alanine Triethanol amine (BLATEA) salt was synthesized by solution method and it was subjected to solubility studies. Using the solubility data, the saturated solution of the synthesized salt was prepared and single crystals of Bis L-alanine Triethanol amine (BLATEA) were grown from aqueous solution by slow evaporation technique. X-ray diffraction (XRD) study was carried out to confirm the crystal structure. FTIR study reveals the functional groups of the sample. UV-Visible transmittance and absorption spectra were recorded for the sample to analyze the transparency of the grown crystal. Vickers micro hardness values were measured for the sample and from the microhardness study it is observed that BLATEA crystal is a soft material. SHG generation study was carried out to confirm the NLO activity of grown sample and also BLATEA crystal has been analyzed with dielectric展开更多
GaInP is an important material in fabrication of optoelectronic and microwave devices. Growth process of GaInP by MOCVD (metal-organic chemical vapor deposition) was investigated, and the effect of growth parameters o...GaInP is an important material in fabrication of optoelectronic and microwave devices. Growth process of GaInP by MOCVD (metal-organic chemical vapor deposition) was investigated, and the effect of growth parameters on the epilayer properties was discussed. It is found that the distribution coefficient of indium is close to unity, while the growth temperature of GaInP is 700°C. The background concentration at 300K is 5.34×1015cm-3 and Hall mobility is 2.27×103cm2·V-1·S-1.展开更多
A new organic charge transfer molecular complex salt of o-toluidinium picrate (OTP) was synthesised and the single crystals were grown by the slow solvent evaporation solution growth technique using methanol as a solv...A new organic charge transfer molecular complex salt of o-toluidinium picrate (OTP) was synthesised and the single crystals were grown by the slow solvent evaporation solution growth technique using methanol as a solvent at room temperature. Formation of the new crystal has been confirmed by single crystal X-ray diffraction (XRD) and NMR spectroscopic techniques. The crystal structure determined by single crystal X-ray diffraction indicates that both the cation and the anion are interlinked to each other by three types of intermolecular hydrogen bonds, namely N(4)-H(4A)···O(7), N(4)-H(4B)···O(5) and N(4)-H(4C)···O(7). The title compound (OTP) crystallizes in monoclinic crystal system with the centrosymmetric space group P21/c. Fourier transform infrared (FT IR) spectral analysis was used to confirm the presence of various functional groups in the grown crystal. The optical properties were analyzed by the UV-Vis-NIR and fluorescence emission studies.展开更多
基金Supported by Agricultural High-tech Project of Jiangsu Province(BG2006304)~~
文摘[Objective] The paper aims to study the relationship between genetic polymorphisms of three gene loci and growth character of Haimen Goats to provide reference to promote Haimen Goat growth character and cultivate Haimen Goat new strain of fast-growth.[Method] We processed analysis and related statistical analysis on three gene loci of Haimen Goats with PCR-RFLP and PCR-SSCP.[Result] The results suggested that there were two genotypes in MSTN gene IntronⅡ,GH gene exonⅠ and GH gene exonⅡ in Haimen Goats.Different genotypes of these gene loci had different effects on relative growth character of Haimen Goats.[Conclusion] This study had a significant meaning about promoting Haimen Goat avoirdupois by marker assistant option.
基金The work was financially supported by the National Natural Science Foundation of China (No.50541003) and the Aeronautic ScienceFoundation of China (No.04H51002).
文摘Anodization of AZ91D magnesium alloy in the electrolyte solution of 0.5 mol/L of sodium silicate and 1.0 mol/L of potassium fluoride was investigated. The anodic films were characterized using optical microscopy （OM）, scanning electron microscopy （SEM）, and X-ray diffraction （XRD）. The corrosion resistance of the various anodized alloys was evaluated by a fast corrosion test using the solution of hydrochloric acid and potassium dichromate. The results showed that the addition of KF resulted in the presence of NaF in the anodic film. The thickness of the anodic film formed under a constant current density of 20 mA/cm^2 for 16 rain at 60℃ exceeded 100 gm. The growth of the anodic film could be divided into three stages based on the anodizing time; the growth rate was much faster during stage Ⅱ than in stages I and Ⅲ. The anodic film exhibited the highest corrosion resistance for the AZ91 alloy, which is attributed to the fact that the anodization was maintained until the end of stage Ⅱ.
文摘The growth character and microstructure of high-T_c supereonducting YBCO thin films deposited on vari- ous substrates have been studied by X-ray diffraction, TEM and SEM.The results show that when the substrate temperaturc is around 700～800℃ the films have a highly oriented texture with c-axis pependicular to the substrate. The structure of the single crystalline YBCO films grown epitaxially at optimal substrate tem- perature of 800℃ has been established by X-ray diffraction using Seemann-Bohlin geometry (SB). Brentano-Bragg geometry(BB),transmission Laue method and TEM. The lattice matching required for epitaxial growth is achievcd by azimuthal adjustment of the film plane with respect to the substrate plane. The sperior growth is demonstrated by film properties such as critical current density(2.4×10~6 A /cm^2,3.4× 10~6 A/cm^2 and 4.7×l0~6 A/cm^2) for films deposited on YSZ[(Zr(Y)O_2],SrTiO_3 and LaAIO_3 respectively at 77 K and zero fie1d.
基金This research was financially supported by the Fundamental Research Funds for the Central Universities No. 2014QNA76, the Natural Science Foundation of Jiangsu Province No. BK20140178, the National Natural Science Foundation of China Nos. 11502282 and 41572263, the China Scholarship Council No.201506425040. Center of collaborative innovation in resource utilization and eco- logical restoration of the old industrial base. This is scientific research platform, temporarily with support number.
文摘The nanosize grain growth characteristics of spherical single-crystal titanium oxide （TiO2） during the rapid gaseous detonation reaction are discussed. Based on the experimental conditions and the Chapman-Jouguet theory, the Kruis model was introduced to simulate the growth characteristics of spherical TiO2 nanoparticles obtained under high pressure, high temperature and by rapid reaction. The results show that the numerical analysis can satisfactorily predict the growth characteristics of spherical TiO2 nanoparticles with diameters of 15-300 nm at different affecting factors, such as concentration of particles, reaction temperature and time, which are in agreement with the obtained experimental results. We found that the increase of the gas-phase reaction temperature, time, and particle concentration affects the growth tendency of spherical nanocrystal TiO2, which provides effective theoretical support for the controllable synthesis of multi-scale nanoparticles.
基金Supported by the National Basic Research Program of China under Grant Nos 2015CB921303,2011CBA00100 and 2012CB821404the Strategic Priority Research Program(B) of Chinese Academy of Sciences under Grant Nos XDB07020100and XDB07020200the National Natural Science Foundation of China under Grant No 11174350
文摘We report on the single crystal growth and superconducting properties of PbTaSe2 with the non-centrosymmetric crystal structure. By using the chemicM vapor transport technique, centimeter-size single crystals are success- fully obtained. The measurement of temperature dependence of electricaJ resistivity p（T） in both normal and superconducting states indicates a quasi-two-dimensional electronic state in contrast to that of polycrystalline samples. Specific heat C（T） measurement reveals a bulk superconductivity with Tc ≈ 3.75K and a specific heat jump ratio of 1.42. All these results are in agreement with a moderately electron-phonon coupled, type-g Bardeen-Cooper-Schrieffer superconductor.
基金Supported by the Key Program of the National Natural Science Foundation of China under Grant No 61334009the National High Technology Research and Development Program of China under Grant No 2014AA032604
文摘CaN nanorods are successfully fabricated by adjusting the flow rate ratio of hydrogen （H2）/nitrogen （N2） and growth temperature of the selective area growth （SAG） method with metal organic chemical vapor deposition （MOCVD）. The SAG template is obtained by nanospherical-lens photolithography. It is found that increasing the flow rate of 1-12 will change the CaN crystal shape from pyramid to vertical rod, while increasing the growth temperature will reduce the diameters of GaN rods to nanometer scale. Finally the CaN nanorods with smooth lateral surface and relatively good quality are obtained under the condition that the H2：N2 ratio is 1：1 and the growth temperature is 1030℃. The good crystal quality and orientation of GaN nanorods are confirmed by high resolution transmission electron microscopy. The cathodoluminescence spectrum suggests that the crystal and optical quality is also improved with increasing the temperature.
基金supported by the National Natural Science Foundation of China (31100364)the National Nonprofit Institute Research Grant of Chinese Academy of Agricultural Sciences (CAAS, IARRP-2014-20)
文摘Aiming at searching for plant growth promoting rhizobacteria (PGPR), a bacterium strain coded as 7016 was isolated from soybean rhizosphere and was characterized in the present study. It was identiifed as Burkholderia sp. based on 16S rDNA sequence analysis, as wel as phenotypic and biochemical characterizations. This bacterium presented nitrogenase activity, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity and phosphate solubilizing ability;inhibited the growth of Sclerotinia sclerotiorum, Gibberel a zeae and Verticil ium dahliae;and produced smal quantities of indole acetic acid (IAA). In green house experiments, signiifcant increases in shoot height and weight, root length and weight, and stem diameter were observed on tomato plants in 30 d after inoculation with strain 7016. Result of 16S rDNA PCR-DGGE showed that 7016 survived in the rhizosphere of tomato seedlings. In the ifeld experiments, Burkholderia sp. 7016 enhanced the tomato yield and signiifcantly promoted activities of soil urease, phosphatase, sucrase, and catalase. Al these results demonstrated Burkholderia sp. 7016 as a valuable PGPR and a candidate of biofertilizer.
基金supported by National Key Research and Development Plan of China (No. 2017YFB0404103)National Natural Science Foundation of China (No. 51702297)Tianjin Science and Technology Plan Project (No. 17YFZCGX00520)
文摘Large size AlN bulk crystal has been grown on SiC heterogeneous seed by physical vapor transport (PVT). The properties of AlN wafer were characterized by high resolution X-ray diffraction (HRXRD), Raman spectroscopy, etched method and atomic force microscope (AFM). Growth mechanism of AlN crystal grown on heterogeneous SiC seeds was proposed. Crystallization quality of AlN samples were improved with the growth process, which is associated with the growth mechanism. AlN single wafer has excellent crystallization quality, which is indicated by HRXRD showing the (0002),(1012) XRD FWHM of 76.3,52.5 arcsec, respectively. The surface of the AlN wafer is measured by AFM with a roughnessof 0.15 nm, which is a promising seed for AlN homogeneous growth.
基金Supported by the Aeronautical Science Foundation of China under Grant No 20132435the National High-Technology Research and Development Program of China under Grant No 2013AA031903+1 种基金the National Natural Science Foundation of China under Grant Nos 61106013 and 61275107the China Postdoctoral Science Foundation under Grant No 2014M560936
文摘InAs1-xSbx with different compositions is grown by molecular beam epitaxy on （100）-oriented semi-insulating GaAs substrates. The increase of Sb content in the epilayer results in the deterioration of crystal quality and surface morphology. Hall measurements show that the carrier concentration increases with the composition of Sb. The electron mobility decreases initially, when Sb composition exceeds a certain value, and the mobility increases slightly. In this work, we emphasize the comparison of crystal quality, surface morphology and electrical properties of epilayers with different Sb compositions.
基金Supported by the Youth Innovation Promotion Association of Chinese Academy of Sciences under Grant No 2015094the National Natural Science Foundation of China under Grant Nos 61204012,61274049 and 61376058+1 种基金the Beijing Natural Science Foundation under Grant Nos 4142053 and 4132070the Beijing Nova Program under Grant Nos 2010B056 and xxhz201503
文摘We report the growth of InSb layers directly on GaAs （001） substrates without any buffer layers by molecular beam epitaxy （MBE）. Influences of growth temperature and V/Ⅲ flux ratios on the crystal quality, the surface morphology and the electrical properties of InSb thin films are investigated. The InSb samples with room- temperature mobility of 44600cm2/Vs are grown under optimized growth conditions. The effect of defects in InSb epitaxial on the electrical properties is researched, and we infer that the formation of In vacancy （VIn） and Sb anti-site （SbIn） defects is the main reason for concentrations changing with growth temperature and Sb2/In flux ratios. The mobility of the InSb sample as a function of temperature ranging from 90 K to 360K is demonstrated and the dislocation scattering mechanism and phonon scattering mechanism are discussed.
基金supported by the National Natural Science Foundation of China (50590401)
文摘By using Tb407 and MoO3 as starting materials, ferroelectric Tb2（MoO4）3 crystal was grown by the Czochralski method. The as-grown crystal was pale green color, transparent and crack-free. X-ray powder diffraction （XRPD）, transmission spectrum, dielectric constant and polarization-electric field （P-E） hysteresis loop measurements were performed to characterize the crystal. The XRPD confirmed the as-grown crystal to be Tb2（MoO4）3. The transmission spectrum of the crystal showed that its transmittance in the entire visible and most near-infrared region was more than 70% except for an absorption peak around 486 nm. Obvious dielectric anomaly could be observed at low frequencies with increasing temperature through the dielectric constant measurement and the Curie temperature of Tb2（MoO4）3 crystal was determined to be 162.3℃ The unsaturated P-E hysteresis loops indicated that it was difficult for the ferroelectric domains in Tb2（MoO4）3 crystal to array regularly with repeated switching of the electric field.
文摘A nonlinear optical crystal of gamma glycine was grown by slow evaporation solution growth technique using deionized water and sodium acetate. The functional groups and vibrational frequencies were identified using FTIR spectral analysis. The cell parameters were determined from single crystal X-ray diffraction analysis. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were used to study its thermal properties. The optical transmittance window and lower cutoff wavelength have been identified by UV-absorption spectrum analysis. Second harmonic generation (SHG) efficiency measurement was carried out by powder Kurtz method.
文摘AlxIn1-xAs with 0.47&lex&le0.62 onto (100) oriented InP substrate was grown by molecular beam epitaxy (MBE) and characterized with X-ray double crystal diffraction, low temperature photoluminescence and an electron probe. Results show their high qualities. Strain and residual stress were studied in detail.
文摘Rhizobia are vital for nitrogen input, fertility of soil and legume plant growth. Knowledge on rhizobial diversity from arid and semiarid areas is important for dry land agriculture in the context of climatic change and for economic utilization. This study provides morphological, biochemical, stress tolerance and plant growth promoting characteristics of fifteen rhizobial isolates from the nodules of same number of wild legumes and one isolate from cultivated Arachis hypogea from semi-arid region, Tirupati. The bacterial isolates were confirmed as rhizobia based on colony morphology and biochemical tests. Based on the colour change of YMA-BTB medium, eight isolates were identified as slow growers and six were fast growers. The isolates differed in growth pattern, colony morphology, antibiotic resistance at higher concentrations and uniformity in utilization of carbon and nitrogen sources. The isolates are tolerant to NaCl up to one percent, displayed normal growth at temperatures 28℃ - 30℃, at neutral pH and poor growth at pH 5and 9. The isolates varied in the production of EPS and IAA, positive for phosphate solubilization and siderophore formation. This functional diversity displayed by the isolates can be utilised for the legume crop production by cross inoculation.
文摘Nonlinear optical single crystals of Ethylene Diamine Tetra Acetate (EDTA) doped lithium sulphate monohydrate are successfully grown by using slow evaporation technique at room temperature with double distilled water as solvent. In order to know its suitability for device fabrication, different characterization analyses have been performed. The single crystal X-ray diffraction (XRD) and powder X-ray diffraction methods are used for identifying the structural parameters of grown crystals. It is found that the addition of dopant doesn’t change the crystal structure. The range and percentage of optical transmission as well as absorption are ascertained by recording UV-Vis-NIR spectrum. No absorption in the entire visible region implies that it is a potential candidate for optoelectronic applications. The modes of vibration of different groups present in the crystals are identified by FT-IR technique. To understand the thermal properties, thermo gravimetric and differential thermal analyses (TGA & DTA) were carried out. The melting point was confirmed by differential scanning calorimetric (DSC) analysis. The amount of dopant included into the crystals was estimated by colorimetric method. The second harmonic generation efficiency measured by Kurtz powder technique is 0.53 times that of potassium dihydrogen orthophosphate.
文摘Bis L-alanine Triethanol amine (BLATEA) salt was synthesized by solution method and it was subjected to solubility studies. Using the solubility data, the saturated solution of the synthesized salt was prepared and single crystals of Bis L-alanine Triethanol amine (BLATEA) were grown from aqueous solution by slow evaporation technique. X-ray diffraction (XRD) study was carried out to confirm the crystal structure. FTIR study reveals the functional groups of the sample. UV-Visible transmittance and absorption spectra were recorded for the sample to analyze the transparency of the grown crystal. Vickers micro hardness values were measured for the sample and from the microhardness study it is observed that BLATEA crystal is a soft material. SHG generation study was carried out to confirm the NLO activity of grown sample and also BLATEA crystal has been analyzed with dielectric
文摘GaInP is an important material in fabrication of optoelectronic and microwave devices. Growth process of GaInP by MOCVD (metal-organic chemical vapor deposition) was investigated, and the effect of growth parameters on the epilayer properties was discussed. It is found that the distribution coefficient of indium is close to unity, while the growth temperature of GaInP is 700°C. The background concentration at 300K is 5.34×1015cm-3 and Hall mobility is 2.27×103cm2·V-1·S-1.
文摘A new organic charge transfer molecular complex salt of o-toluidinium picrate (OTP) was synthesised and the single crystals were grown by the slow solvent evaporation solution growth technique using methanol as a solvent at room temperature. Formation of the new crystal has been confirmed by single crystal X-ray diffraction (XRD) and NMR spectroscopic techniques. The crystal structure determined by single crystal X-ray diffraction indicates that both the cation and the anion are interlinked to each other by three types of intermolecular hydrogen bonds, namely N(4)-H(4A)···O(7), N(4)-H(4B)···O(5) and N(4)-H(4C)···O(7). The title compound (OTP) crystallizes in monoclinic crystal system with the centrosymmetric space group P21/c. Fourier transform infrared (FT IR) spectral analysis was used to confirm the presence of various functional groups in the grown crystal. The optical properties were analyzed by the UV-Vis-NIR and fluorescence emission studies.
