Formamidinium lead bromide(FAPbBr_(3))nanocrystals(NCs)have been considered to be a good optoelectronic material due to their pure green emission,excellent stability and superior carrier transport characteristics.Howe...Formamidinium lead bromide(FAPbBr_(3))nanocrystals(NCs)have been considered to be a good optoelectronic material due to their pure green emission,excellent stability and superior carrier transport characteristics.However,two-photon pumped amplified spontaneous emission(ASE)and the corresponding nonlinear optical properties of FAPbBr_(3) NCs are scarcely revealed.Herein,we synthesized colloidal FAPbBr_(3) NCs with different sizes by changing the molar ratio of FABr/PbBr_(2) in the precursor solution,using ligand assisted precipitation(LARP)technology at room temperature.Photoluminescence(PL)and time resolved photoluminescence(TRPL)spectroscopy were measured to characterize their ASE properties.And their nonlinear optical properties were studied through the Zscan technique and the two-photon excited fluorescence method.The stimulated emission properties including oneand two-photon pumped ASE have been realized from FAPbBr_(3) NCs.With large two-photon absorption coefficient(0.27 cm/GW)and high non-linear absorption cross-section(7.52×10^(5) GM),ASE with threshold as low as 9.8μJ/cm^(2) and 487μJ/cm^(2) have been obtained from colloidal FAPbBr_(3) NCs using one-and two-photon excitations.These results indicate that as a new possible green-emitting frequency-upconversion material with low thresholds,FAPbBr_(3) NCs hold great potential in the development of high-performance two-photon pump lasers.展开更多
Carbon nanotubes (CNTs) are synthesized from methane and hydrogen gas mixture directly on stainless steel plates by microwave plasma chemical vapor deposition (MWPCVD).By varying pretreatment conditions of the substra...Carbon nanotubes (CNTs) are synthesized from methane and hydrogen gas mixture directly on stainless steel plates by microwave plasma chemical vapor deposition (MWPCVD).By varying pretreatment conditions of the substrates such as mechanically polishing and acid washing,it is found the polishing and acid washing can lower the turn-on field and improve the emission current density.The current density of the un-pretreated sample attains 1.2mA/cm 2,but the polished sample and polished acidly washed sample attain 3.2 and 2.75mA/cm 2,respectively,at the electric field of 6.25V/μm.展开更多
Aim The several species of the genus Paris called ＂Chonglou＂ are famous traditional Chinese herbal medicines. We established the quantitative analysis method of the steroidal saponins in some species of the genus Pa...Aim The several species of the genus Paris called ＂Chonglou＂ are famous traditional Chinese herbal medicines. We established the quantitative analysis method of the steroidal saponins in some species of the genus Paris and discussed their relations. Methods We detected the contents of 11 steroidal saponins in Paris samples with a Kromasel C18 （ 150 mm× 4.6 mm ID, 5μm） column which was subjected to gradient elution with acetonitrile-water （30：70- 60：40, V/V） at a flow rate of 1 mL· min^-1 by HPLC-ELSD and established chemical cluster tree using SPSS 11 software. Results All the samples could be separated and calibration curves of 11 saponins were prepared. We successfully detected the contents of 11 steroidal saponins in 14 Paris spp. in 30 min. The recovery for the assay of saponins was between 95 % and 97 %. The RSD of precision of 11 saponins and stability of samples were below 3 %. Chemical phylogenetic tree based on saponin contents indicated that 17 samples of Paris spp. clustered separately. Conclusion The established method is accurate and convenient, and suitable for the quantitative analysis of these 11 steroidal saponins in Paris spp.. The chemical phylogenetic tree is in accordance with Takhtajian classical taxonomy.展开更多
In order to build method for measuring of elements in honey, the contents of Ba, Cu, Pb, Cd, As, Hg, Cr, Mn, Se had been determined by microwave diges- tion （MWD） and actively coupled plasma atomic emission spectrom...In order to build method for measuring of elements in honey, the contents of Ba, Cu, Pb, Cd, As, Hg, Cr, Mn, Se had been determined by microwave diges- tion （MWD） and actively coupled plasma atomic emission spectrometry （ICP-AES）. The results show that, the range of heavy metal elements were in the range of 0- 10.0 mg/L, with good linear relationship. In addition, all correlation coefficients kept higher than 0.999, and the recovery rate of ample added with standard solution was in 94.1%-110%. By comparison with the result of chemical experiment, the method was quickly accessible and convenient, widely used in the measurement of elements in honey, with satisfactory results.展开更多
A novel fabrication process related to a smoothly wet chemical etching profile o f InP-based epitaxial layers in the crystal direction of [01for an InP-based monol ithic vertically integrated transmitter with an M...A novel fabrication process related to a smoothly wet chemical etching profile o f InP-based epitaxial layers in the crystal direction of [01for an InP-based monol ithic vertically integrated transmitter with an MQW laser diode and a heterojunction bipolar tran sistors driver circuit is described.A clear eye output diagram via an O/E converter is demonstrat ed und er a 1.25Gb/s non-return-zero pseudorandom code with a pattern length of 2 the integrated transmitter has a power dissipation of about 120mW with an optical output of 2dBm.展开更多
The vertical cavity surface emitting laser (VCSEL) arrays and VCSEL-based optical transmission modules are investigated.It includes the VCSEL's spectral characteristic,modulation characteristic,high frequency char...The vertical cavity surface emitting laser (VCSEL) arrays and VCSEL-based optical transmission modules are investigated.It includes the VCSEL's spectral characteristic,modulation characteristic,high frequency characteristic,and compatibility with microelectronic circuit.The module consists of 1×16 VCSEL array and 16-channel lasers driver with 0.35μm CMOS circuit by hybrid integration.During the test process,the module operates well at more than 2GHz in -3dB frequency bandwidth.展开更多
A reverse bias silicon p-n junction based on light emitting diode is designed in standard 0.6μm industrial CMOS technology.The mechanism of the light emitting of this device is discussed.The device is simulated by th...A reverse bias silicon p-n junction based on light emitting diode is designed in standard 0.6μm industrial CMOS technology.The mechanism of the light emitting of this device is discussed.The device is simulated by the commercial software.I-V characteristic under forward or reverse bias is simulated utilizing the commercial software.The results between simulation and experiment data are compared.The results show that it is a promising device and may find applications in light linking.展开更多
A new process method is proposed to improve the light output power of GaAs vertical cavity surface-emitting lasers （VCSELs）. The VCSELs with open-annulus-distributed holes have a light output power 1.34 times higher...A new process method is proposed to improve the light output power of GaAs vertical cavity surface-emitting lasers （VCSELs）. The VCSELs with open-annulus-distributed holes have a light output power 1.34 times higher than those with ring trenches. The 14μm-aperture devices have a light output power higher than 10mW and have a maximum of 12.48mW at 29.6mA. In addition,open-annulus-distributed holes offer bridges for current injection,so the connecting Ti-Au metal between the ohmic contact and bonding pad does not have to cross the ring trench, and it therefore would not cause the connecting metal to be broken. These VCSELs also show high-temperature operation capabilities,and they have a maximum output power of 8mW even at an operation temperature of up to 60℃.展开更多
In order to develop a method for measuring of elements in Sipunculus nudus, the contents of Cu, Pb, Cd, Cr, Mn, As, Hg and Ba were determined by actively coupled plasma atomic emission spectrometry （MWD） and microwa...In order to develop a method for measuring of elements in Sipunculus nudus, the contents of Cu, Pb, Cd, Cr, Mn, As, Hg and Ba were determined by actively coupled plasma atomic emission spectrometry （MWD） and microwave digestion （ICP-AES）. The results showed that correlation coefficients al kept higher than 0.999 and the recovery rates of sample added standard solutions were in 98%-114%. The results indicated that the contents of Cu, Pb, Cd, Cr, Mn, As, Hg and Ba were 17.119, 3.781, 0.695, 7.351, 1997.982, 0.620, 0.144, 4.249 mg/kg respectively. The contents of Mn exceeded national limit by hundredfold, Cd sevenfold, Pd fourfold, Cd three-and-a-half-fold, and As onefold. Sipunculs nudus became seriously pol uted. Therefore, it is necessary to formulate robust policies to fol ow closely and pay close attention to coastal areas pol ution around Dongfang City.展开更多
Top-emitting oxide-confined intra-cavity contact structure 980nm VCSEL is fabricated by low-pressure metal organic chemical-vapor deposition (LP-MOCVD).Self-aligning etching process and selective oxidation are applied...Top-emitting oxide-confined intra-cavity contact structure 980nm VCSEL is fabricated by low-pressure metal organic chemical-vapor deposition (LP-MOCVD).Self-aligning etching process and selective oxidation are applied for current confinement.Output light power of 10.1mW and slope efficiency of 0.462mW/mA are obtained under room temperature,pulse operation,and injection current of 28mA.The maximum light power is 13.1mW under pulse operation.Output light power of 7.1mW,lasing wavelength of 974nm,and FWHM of 0.6nm are obtained under CW condition.The study of oxide-aperture influence on threshold current and differential resistance shows that lower threshold current can be obtained with a smaller oxide-aperture diameter.展开更多
A simple, rapid and sensitive flow injection chemiluminescence （FI-CL） method has been developed for the determination of meloxicam. The method is based on the CL-emitting reaction between meloxicam and potassium pe...A simple, rapid and sensitive flow injection chemiluminescence （FI-CL） method has been developed for the determination of meloxicam. The method is based on the CL-emitting reaction between meloxicam and potassium permanganate in a hydrochloric acid medium, enhanced by formaldehyde （HCHO）. Under optimum conditions, calibration curve over the range of 1.0-20.0μg/mL was obtained. The proposed method was successfully applied to the determination of meloxicam in capsules with no evi- dence of interference from common excipients. The detection limit of this method was 25.6 ng/mL. The relative standard deviation was 2.1% for 10.0 μg/mL meloxicam. The sample throughput was found to be 120 samples/h.展开更多
A novel bifunctional blue-light material, 9-（pyren-l-yl）-9H-carbazole （CzPy）, has been synthesized and its structure is identified by electron ionization mass spectrometry, 1H NMR, and element analysis. The absorp...A novel bifunctional blue-light material, 9-（pyren-l-yl）-9H-carbazole （CzPy）, has been synthesized and its structure is identified by electron ionization mass spectrometry, 1H NMR, and element analysis. The absorption, photoluminescence spectra and thermal properties were studied, results showedthat CzPy was stable under ambient conditions with a blue-light emission （461 nm）. Additionally, its electroluminescence properties were characterized with four different devices. Results indicated a maximum luminous efficiency reached 1.56 cd/A and maximum luminance up to 3526 cd/m2 at 10 V with commission international De L＇ Eclairage coordinates of （0.20, 0.24） when it was used as emitter. Furthermore, CzPy also indicated hole-transporting ability.展开更多
Lateral oxidation in vertical cavity surface emitting lasers （VCSELs） is described,and its characteristics are investigated.A linear growth law is found for stripe mesas. However, oxide growth （above 435℃ ） follo...Lateral oxidation in vertical cavity surface emitting lasers （VCSELs） is described,and its characteristics are investigated.A linear growth law is found for stripe mesas. However, oxide growth （above 435℃ ） follows a nonlinear law for the two geometry mesa structures which we employ in VCSEL. Theoretical analysis indicates that mesa structure geometry influences oxide growth rate at higher temperatures.展开更多
文摘Formamidinium lead bromide(FAPbBr_(3))nanocrystals(NCs)have been considered to be a good optoelectronic material due to their pure green emission,excellent stability and superior carrier transport characteristics.However,two-photon pumped amplified spontaneous emission(ASE)and the corresponding nonlinear optical properties of FAPbBr_(3) NCs are scarcely revealed.Herein,we synthesized colloidal FAPbBr_(3) NCs with different sizes by changing the molar ratio of FABr/PbBr_(2) in the precursor solution,using ligand assisted precipitation(LARP)technology at room temperature.Photoluminescence(PL)and time resolved photoluminescence(TRPL)spectroscopy were measured to characterize their ASE properties.And their nonlinear optical properties were studied through the Zscan technique and the two-photon excited fluorescence method.The stimulated emission properties including oneand two-photon pumped ASE have been realized from FAPbBr_(3) NCs.With large two-photon absorption coefficient(0.27 cm/GW)and high non-linear absorption cross-section(7.52×10^(5) GM),ASE with threshold as low as 9.8μJ/cm^(2) and 487μJ/cm^(2) have been obtained from colloidal FAPbBr_(3) NCs using one-and two-photon excitations.These results indicate that as a new possible green-emitting frequency-upconversion material with low thresholds,FAPbBr_(3) NCs hold great potential in the development of high-performance two-photon pump lasers.
文摘Carbon nanotubes (CNTs) are synthesized from methane and hydrogen gas mixture directly on stainless steel plates by microwave plasma chemical vapor deposition (MWPCVD).By varying pretreatment conditions of the substrates such as mechanically polishing and acid washing,it is found the polishing and acid washing can lower the turn-on field and improve the emission current density.The current density of the un-pretreated sample attains 1.2mA/cm 2,but the polished sample and polished acidly washed sample attain 3.2 and 2.75mA/cm 2,respectively,at the electric field of 6.25V/μm.
文摘Aim The several species of the genus Paris called ＂Chonglou＂ are famous traditional Chinese herbal medicines. We established the quantitative analysis method of the steroidal saponins in some species of the genus Paris and discussed their relations. Methods We detected the contents of 11 steroidal saponins in Paris samples with a Kromasel C18 （ 150 mm× 4.6 mm ID, 5μm） column which was subjected to gradient elution with acetonitrile-water （30：70- 60：40, V/V） at a flow rate of 1 mL· min^-1 by HPLC-ELSD and established chemical cluster tree using SPSS 11 software. Results All the samples could be separated and calibration curves of 11 saponins were prepared. We successfully detected the contents of 11 steroidal saponins in 14 Paris spp. in 30 min. The recovery for the assay of saponins was between 95 % and 97 %. The RSD of precision of 11 saponins and stability of samples were below 3 %. Chemical phylogenetic tree based on saponin contents indicated that 17 samples of Paris spp. clustered separately. Conclusion The established method is accurate and convenient, and suitable for the quantitative analysis of these 11 steroidal saponins in Paris spp.. The chemical phylogenetic tree is in accordance with Takhtajian classical taxonomy.
文摘In order to build method for measuring of elements in honey, the contents of Ba, Cu, Pb, Cd, As, Hg, Cr, Mn, Se had been determined by microwave diges- tion （MWD） and actively coupled plasma atomic emission spectrometry （ICP-AES）. The results show that, the range of heavy metal elements were in the range of 0- 10.0 mg/L, with good linear relationship. In addition, all correlation coefficients kept higher than 0.999, and the recovery rate of ample added with standard solution was in 94.1%-110%. By comparison with the result of chemical experiment, the method was quickly accessible and convenient, widely used in the measurement of elements in honey, with satisfactory results.
文摘A novel fabrication process related to a smoothly wet chemical etching profile o f InP-based epitaxial layers in the crystal direction of [01for an InP-based monol ithic vertically integrated transmitter with an MQW laser diode and a heterojunction bipolar tran sistors driver circuit is described.A clear eye output diagram via an O/E converter is demonstrat ed und er a 1.25Gb/s non-return-zero pseudorandom code with a pattern length of 2 the integrated transmitter has a power dissipation of about 120mW with an optical output of 2dBm.
文摘The vertical cavity surface emitting laser (VCSEL) arrays and VCSEL-based optical transmission modules are investigated.It includes the VCSEL's spectral characteristic,modulation characteristic,high frequency characteristic,and compatibility with microelectronic circuit.The module consists of 1×16 VCSEL array and 16-channel lasers driver with 0.35μm CMOS circuit by hybrid integration.During the test process,the module operates well at more than 2GHz in -3dB frequency bandwidth.
文摘A reverse bias silicon p-n junction based on light emitting diode is designed in standard 0.6μm industrial CMOS technology.The mechanism of the light emitting of this device is discussed.The device is simulated by the commercial software.I-V characteristic under forward or reverse bias is simulated utilizing the commercial software.The results between simulation and experiment data are compared.The results show that it is a promising device and may find applications in light linking.
文摘A new process method is proposed to improve the light output power of GaAs vertical cavity surface-emitting lasers （VCSELs）. The VCSELs with open-annulus-distributed holes have a light output power 1.34 times higher than those with ring trenches. The 14μm-aperture devices have a light output power higher than 10mW and have a maximum of 12.48mW at 29.6mA. In addition,open-annulus-distributed holes offer bridges for current injection,so the connecting Ti-Au metal between the ohmic contact and bonding pad does not have to cross the ring trench, and it therefore would not cause the connecting metal to be broken. These VCSELs also show high-temperature operation capabilities,and they have a maximum output power of 8mW even at an operation temperature of up to 60℃.
文摘In order to develop a method for measuring of elements in Sipunculus nudus, the contents of Cu, Pb, Cd, Cr, Mn, As, Hg and Ba were determined by actively coupled plasma atomic emission spectrometry （MWD） and microwave digestion （ICP-AES）. The results showed that correlation coefficients al kept higher than 0.999 and the recovery rates of sample added standard solutions were in 98%-114%. The results indicated that the contents of Cu, Pb, Cd, Cr, Mn, As, Hg and Ba were 17.119, 3.781, 0.695, 7.351, 1997.982, 0.620, 0.144, 4.249 mg/kg respectively. The contents of Mn exceeded national limit by hundredfold, Cd sevenfold, Pd fourfold, Cd three-and-a-half-fold, and As onefold. Sipunculs nudus became seriously pol uted. Therefore, it is necessary to formulate robust policies to fol ow closely and pay close attention to coastal areas pol ution around Dongfang City.
文摘Top-emitting oxide-confined intra-cavity contact structure 980nm VCSEL is fabricated by low-pressure metal organic chemical-vapor deposition (LP-MOCVD).Self-aligning etching process and selective oxidation are applied for current confinement.Output light power of 10.1mW and slope efficiency of 0.462mW/mA are obtained under room temperature,pulse operation,and injection current of 28mA.The maximum light power is 13.1mW under pulse operation.Output light power of 7.1mW,lasing wavelength of 974nm,and FWHM of 0.6nm are obtained under CW condition.The study of oxide-aperture influence on threshold current and differential resistance shows that lower threshold current can be obtained with a smaller oxide-aperture diameter.
文摘A simple, rapid and sensitive flow injection chemiluminescence （FI-CL） method has been developed for the determination of meloxicam. The method is based on the CL-emitting reaction between meloxicam and potassium permanganate in a hydrochloric acid medium, enhanced by formaldehyde （HCHO）. Under optimum conditions, calibration curve over the range of 1.0-20.0μg/mL was obtained. The proposed method was successfully applied to the determination of meloxicam in capsules with no evi- dence of interference from common excipients. The detection limit of this method was 25.6 ng/mL. The relative standard deviation was 2.1% for 10.0 μg/mL meloxicam. The sample throughput was found to be 120 samples/h.
基金This work was supported by the National Natural Science Foundation of China （No.20671036）, the Natural Science Foundation of Guangdong Province （No.2007A010500008 and No.2008B010800030）, and the Scientific Research Foundation of Nanchang Hangkong University.
文摘A novel bifunctional blue-light material, 9-（pyren-l-yl）-9H-carbazole （CzPy）, has been synthesized and its structure is identified by electron ionization mass spectrometry, 1H NMR, and element analysis. The absorption, photoluminescence spectra and thermal properties were studied, results showedthat CzPy was stable under ambient conditions with a blue-light emission （461 nm）. Additionally, its electroluminescence properties were characterized with four different devices. Results indicated a maximum luminous efficiency reached 1.56 cd/A and maximum luminance up to 3526 cd/m2 at 10 V with commission international De L＇ Eclairage coordinates of （0.20, 0.24） when it was used as emitter. Furthermore, CzPy also indicated hole-transporting ability.
文摘Lateral oxidation in vertical cavity surface emitting lasers （VCSELs） is described,and its characteristics are investigated.A linear growth law is found for stripe mesas. However, oxide growth （above 435℃ ） follows a nonlinear law for the two geometry mesa structures which we employ in VCSEL. Theoretical analysis indicates that mesa structure geometry influences oxide growth rate at higher temperatures.
