Dipyrido [3, 2-a:2,3-c] phenazine moiety has been introduced as neutral ligand in europium complex. Therefore, a new europium complex with saturated emission, strong fluorescent intensity and good solubility was desi...Dipyrido [3, 2-a:2,3-c] phenazine moiety has been introduced as neutral ligand in europium complex. Therefore, a new europium complex with saturated emission, strong fluorescent intensity and good solubility was designed and synthesized for the first time. Its photoluminescence and UV properties were examined. The experimental results showed that this new Eu-complex could be used as red electroluminescent materials.展开更多
A novel binuclear europium P-diketone complex with squaric acid ligand was synthesized for the first time. Its structure was elucidated by IR, UV, and Elemental Analysis. Red light emitting diode (LED) was fabricated ...A novel binuclear europium P-diketone complex with squaric acid ligand was synthesized for the first time. Its structure was elucidated by IR, UV, and Elemental Analysis. Red light emitting diode (LED) was fabricated by using the novel europium complex as an emitting layer, tris(8-quinolinolate) aluminum (III) (Alq(3)) as an electron-transporting layer, N, N'-diphenyl-N, N'-(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD) as a hole-transporting layer. A cell structure of indium-tin-oxide/TPD/Eu-complex/Alq(3)/Mg: Ag was employed. Red electroluminescence was observed at room temperature with dc bias voltage of 2 V in this cell. 2 Red emission peaks at about 613 nm with maximum luminance of over 106 cd/m(2). Compared with the EL luminance from those europium complexes reported before, one from the Eu-complex is best in the same cells.展开更多
Two new binuclear (europium and lanthanum) beta-diketone complexes Eu0.9La0.1(TTA)(3)Phen and Eu0.5La0.5(TTA)(3)Phen in which Phen is 1,10-phenanthroline, TTA is an anion of thenoyltrifluoroacetone (HTTA) were synthes...Two new binuclear (europium and lanthanum) beta-diketone complexes Eu0.9La0.1(TTA)(3)Phen and Eu0.5La0.5(TTA)(3)Phen in which Phen is 1,10-phenanthroline, TTA is an anion of thenoyltrifluoroacetone (HTTA) were synthesized for the first time. They showed intense photoluminescence (PL) and mechanoluminescence (ML), and had their maximum PL and ML spectra peaked at 613.5 nm with half bandwidth of 10 nm respectively. Their PL and ML intensity were obviously stronger than these from Eu(TTA)(3)Phen. It is considered that binuclear (europium and lanthanum) beta-diketones complexes are promising ML and PL materials.展开更多
This paper uses survey data regarding native Sichuan entrepreneurs who have developed businesses outside of Sichuan Province and then returned,along with their organizations,to Sichuan.Our goal was to identify and exa...This paper uses survey data regarding native Sichuan entrepreneurs who have developed businesses outside of Sichuan Province and then returned,along with their organizations,to Sichuan.Our goal was to identify and examine the factors influencing their entrepreneurial performance by using SEM-PLS.The results show that policy support,social relations and entrepreneurial self-efficacy have significant roles in entrepreneurial performance.No direct influence from the cultural or market environments was detected.Therefore,this study indicates that for entrepreneurs returning to their hometown the government should provide social and financial support for small and micro sized entrepreneurial ventures while the entrepreneurs should constantly strengthen their entrepreneurial selfefficacy by obtaining information through cultivated social relationships and market opportunities that will allow them to enhance their entrepreneurial performance.展开更多
针对传统极限学习机预测滚动轴承故障时,存在信号模式混叠、人为参数选取造成预测精度低下的问题,提出了正态分布-经验小波变换变换结合偏最小二乘法的极限学习机(partial least squares-extreme learning machines,简称PLS-ELM)的故障...针对传统极限学习机预测滚动轴承故障时,存在信号模式混叠、人为参数选取造成预测精度低下的问题,提出了正态分布-经验小波变换变换结合偏最小二乘法的极限学习机(partial least squares-extreme learning machines,简称PLS-ELM)的故障预测方法。首先,提出正态分布经验小波变换信号降噪方法,通过正态分布划分频率带界限,在各频率带上构建带通滤波器进行降噪;其次,提出PLS-ELM的故障预测方法,应用偏最小二乘法(partial least squares,简称PLS)中主成分数和加载权重分别改进极限学习机(extreme learning machines,简称ELM)隐含层节点数和网络权值,激活函数选取Softmax以提高数据的拟合精度;最后,应用无量纲指标峭度来反映故障程度,实现故障趋势预测。试验结果表明,该方法能够准确划分频谱和克服模式混叠等问题,并实现滚动轴承性能衰退趋势预测。展开更多
Radiation damage produced in 4H-SiC by electrons of different doses is presented by using multiple characterization techniques. Raman spectra results indicate that SiC crystal structures are essentially impervious to ...Radiation damage produced in 4H-SiC by electrons of different doses is presented by using multiple characterization techniques. Raman spectra results indicate that SiC crystal structures are essentially impervious to 10 Me V electron irradiation with doses up to 3000 kGy. However, irradiation indeed leads to the generation of various defects, which are evaluated through photoluminescence(PL) and deep level transient spectroscopy(DLTS). The PL spectra feature a prominent broad band centered at 500 nm, accompanied by several smaller peaks ranging from 660 to 808 nm. The intensity of each PL peak demonstrates a linear correlation with the irradiation dose, indicating a proportional increase in defect concentration during irradiation. The DLTS spectra reveal several thermally unstable and stable defects that exhibit similarities at low irradiation doses.Notably, after irradiating at the higher dose of 1000 kGy, a new stable defect labeled as R_(2)(Ec-0.51 eV) appeared after annealing at 800 K. Furthermore, the impact of irradiation-induced defects on SiC junction barrier Schottky diodes is discussed. It is observed that high-dose electron irradiation converts SiC n-epilayers to semi-insulating layers. However, subjecting the samples to a temperature of only 800 K results in a significant reduction in resistance due to the annealing out of unstable defects.展开更多
The effects of ion damage on Ga NAs/Ga As and Ga In NAs/Ga As quantum wells ( QWs) grown by plas- ma- assisted molecular beam epitaxy have been investigated. Itis found thation damage is a key factor affecting the q...The effects of ion damage on Ga NAs/Ga As and Ga In NAs/Ga As quantum wells ( QWs) grown by plas- ma- assisted molecular beam epitaxy have been investigated. Itis found thation damage is a key factor affecting the quality of Ga NAs and Ga In NAs QWs. Obvious appearance of pendello¨ sung fringes in X- ray diffraction pattern and remarkable im provement in the optical properties of the samples grown with ion removal magnets are observed.By removing nitrogen ions,the PL intensity of the Ga In NAs QW is improved so as to be comparable with that of Ga In As QW. The stronger is the magnetic field,the m ore obvious the PL intensity im provement would be.展开更多
基金This work was supported by the National Natural Science Foundation of China (No29992530-6) and Provincial Natural Science Foundation of Hunan (00JJY2043).
文摘Dipyrido [3, 2-a:2,3-c] phenazine moiety has been introduced as neutral ligand in europium complex. Therefore, a new europium complex with saturated emission, strong fluorescent intensity and good solubility was designed and synthesized for the first time. Its photoluminescence and UV properties were examined. The experimental results showed that this new Eu-complex could be used as red electroluminescent materials.
基金This work was supported by National Natural Science Foundation of China (29972032) and Provincial Natural Science Foundation of Hunan (00JJY2043).
文摘A novel binuclear europium P-diketone complex with squaric acid ligand was synthesized for the first time. Its structure was elucidated by IR, UV, and Elemental Analysis. Red light emitting diode (LED) was fabricated by using the novel europium complex as an emitting layer, tris(8-quinolinolate) aluminum (III) (Alq(3)) as an electron-transporting layer, N, N'-diphenyl-N, N'-(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD) as a hole-transporting layer. A cell structure of indium-tin-oxide/TPD/Eu-complex/Alq(3)/Mg: Ag was employed. Red electroluminescence was observed at room temperature with dc bias voltage of 2 V in this cell. 2 Red emission peaks at about 613 nm with maximum luminance of over 106 cd/m(2). Compared with the EL luminance from those europium complexes reported before, one from the Eu-complex is best in the same cells.
文摘Two new binuclear (europium and lanthanum) beta-diketone complexes Eu0.9La0.1(TTA)(3)Phen and Eu0.5La0.5(TTA)(3)Phen in which Phen is 1,10-phenanthroline, TTA is an anion of thenoyltrifluoroacetone (HTTA) were synthesized for the first time. They showed intense photoluminescence (PL) and mechanoluminescence (ML), and had their maximum PL and ML spectra peaked at 613.5 nm with half bandwidth of 10 nm respectively. Their PL and ML intensity were obviously stronger than these from Eu(TTA)(3)Phen. It is considered that binuclear (europium and lanthanum) beta-diketones complexes are promising ML and PL materials.
文摘This paper uses survey data regarding native Sichuan entrepreneurs who have developed businesses outside of Sichuan Province and then returned,along with their organizations,to Sichuan.Our goal was to identify and examine the factors influencing their entrepreneurial performance by using SEM-PLS.The results show that policy support,social relations and entrepreneurial self-efficacy have significant roles in entrepreneurial performance.No direct influence from the cultural or market environments was detected.Therefore,this study indicates that for entrepreneurs returning to their hometown the government should provide social and financial support for small and micro sized entrepreneurial ventures while the entrepreneurs should constantly strengthen their entrepreneurial selfefficacy by obtaining information through cultivated social relationships and market opportunities that will allow them to enhance their entrepreneurial performance.
文摘针对传统极限学习机预测滚动轴承故障时,存在信号模式混叠、人为参数选取造成预测精度低下的问题,提出了正态分布-经验小波变换变换结合偏最小二乘法的极限学习机(partial least squares-extreme learning machines,简称PLS-ELM)的故障预测方法。首先,提出正态分布经验小波变换信号降噪方法,通过正态分布划分频率带界限,在各频率带上构建带通滤波器进行降噪;其次,提出PLS-ELM的故障预测方法,应用偏最小二乘法(partial least squares,简称PLS)中主成分数和加载权重分别改进极限学习机(extreme learning machines,简称ELM)隐含层节点数和网络权值,激活函数选取Softmax以提高数据的拟合精度;最后,应用无量纲指标峭度来反映故障程度,实现故障趋势预测。试验结果表明,该方法能够准确划分频谱和克服模式混叠等问题,并实现滚动轴承性能衰退趋势预测。
基金supported by the Open Fund(2022E10015)of the Key Laboratory of Power Semiconductor Materials and Devices of Zhejiang Province&Institute of Advanced Semiconductors,ZJU-Hangzhou Global Scientific and Technological Innovation Center。
文摘Radiation damage produced in 4H-SiC by electrons of different doses is presented by using multiple characterization techniques. Raman spectra results indicate that SiC crystal structures are essentially impervious to 10 Me V electron irradiation with doses up to 3000 kGy. However, irradiation indeed leads to the generation of various defects, which are evaluated through photoluminescence(PL) and deep level transient spectroscopy(DLTS). The PL spectra feature a prominent broad band centered at 500 nm, accompanied by several smaller peaks ranging from 660 to 808 nm. The intensity of each PL peak demonstrates a linear correlation with the irradiation dose, indicating a proportional increase in defect concentration during irradiation. The DLTS spectra reveal several thermally unstable and stable defects that exhibit similarities at low irradiation doses.Notably, after irradiating at the higher dose of 1000 kGy, a new stable defect labeled as R_(2)(Ec-0.51 eV) appeared after annealing at 800 K. Furthermore, the impact of irradiation-induced defects on SiC junction barrier Schottky diodes is discussed. It is observed that high-dose electron irradiation converts SiC n-epilayers to semi-insulating layers. However, subjecting the samples to a temperature of only 800 K results in a significant reduction in resistance due to the annealing out of unstable defects.
文摘The effects of ion damage on Ga NAs/Ga As and Ga In NAs/Ga As quantum wells ( QWs) grown by plas- ma- assisted molecular beam epitaxy have been investigated. Itis found thation damage is a key factor affecting the quality of Ga NAs and Ga In NAs QWs. Obvious appearance of pendello¨ sung fringes in X- ray diffraction pattern and remarkable im provement in the optical properties of the samples grown with ion removal magnets are observed.By removing nitrogen ions,the PL intensity of the Ga In NAs QW is improved so as to be comparable with that of Ga In As QW. The stronger is the magnetic field,the m ore obvious the PL intensity im provement would be.
